The present disclosure relates to the field of manufacturing aerospace components, more specifically to the chemical milling of sheet metal. The present invention relates most specifically to the masking process used to pattern and protect the sheet metal substrate prior to chemical milling and further chemical processing. The present disclosure provides compositions and processes for masking substrates for chemical processing using temperature and/or pressure and, optionally, without a solvent carrier or polymerization reaction.
Aerospace parts need to be light and strong. Improved power-to-weight ratio for finished aircraft results in maneuverability, acceleration, and fuel efficiency. Over the years, high strength to weight materials such as aluminum, titanium, and various alloys have gained favor within the aerospace industry. Design of these parts is limited by the imagination of the design engineer and the production technology available to the process engineer. Chemical milling emerged as an enabling technology (Harris, W. T., “Chemical Milling, The Technology of Cutting Materials by Etching,” Oxford University Press, 1976) during the 1950s for production of missile casings and experimental aircraft parts. Evolution of the design of aircraft and spacecraft necessitated application of these weight saving designs to large parts with curvature and complex tapers which were sometimes impossible to process using traditional machining methods. Current commercial aircraft construction makes substantial use of chemical milling to produce fuselage, leading edge, bulkhead, and various other components.
The typical process for chemical milling and chemical processing of aerospace components consists of cleaning the sheet metal, applying a suitable maskant to the sheet metal, forming the sheet metal into a masked part, scribing the masked part, line scaling the masked part, removing select pieces of the maskant while the majority of the maskant remain intact with the part, chemical milling the masked part, cleaning the chemical milled metal surface of the masked part, and further surface treatment steps depending on the final use of the part. Depending on the final use of the part, after further surface treatment, the part can be drilled and/or routed before being “de-masked.” The present disclosure specifically relates to applying the maskant to sheet metal prior to forming or scribing.
Alloys used in the manufacture of aerospace components are selected not only for their strength to weight ratios, but also for their resistance to corrosion. This feature necessitates aggressive chemical milling solutions in order to dissolve away material. The compositions of these chemical milling solutions are known within the industry. The aggressive nature of these chemical milling solutions requires a maskant to be chemically resistant to degradation during this process. A number of suitable maskant compositions are commercially available, typically consisting of a chemically resistant polymer blend dissolved in an organic solvent of appropriate polarity. The compositions of these maskants are typically industry secrets but can be approximated by the composition presented in prior art (U.S. Pat. No. 4,155,801). As organic solvents wane in popularity due to health and environmental concerns, several alternative technologies have presented themselves, each with their own drawbacks, such as two component (100% solids) maskants, water-based maskants (low or zero VOC), and radiation-curable maskants (100% solids, near zero VOC).
Maskant films are generally applied to a workpiece by the following methods: spray application, flow-coating, dip-coating, or brush. Each method has both benefits and downsides in regard to the application efficiency, the uniformity of the applied coating, the presence of defects, and the equipment expenditure required for the process. The alternative maskant technologies such as two-component, water-based, and radiation curable maskants all have application process limitations which prevent widespread adoption as a replacement to solvent based maskants. Briefly, two-component maskants can only be applied via specialized airless spray equipment and suffer from uneven film builds. Water based maskants require long dry times due to the low volatility of water. Radiation-curable maskants require a separate curing stage with the use of high intensity and hazardous ultraviolet light.
There is a need in the art for a masking technology that is 100% solids, zero VOC, and that completely removes solvent from the masking process. The present disclosure solves this unmet need.
In one aspect, the present disclosure provides a polymer film comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C., wherein the polymer film does not adhere to a substrate at standard temperature and standard pressure. In an embodiment, upon contacting the polymer film with a metal substrate under elevated temperature and/or mechanical pressure, the polymer film adheres to the metal substrate. In an embodiment, the film is chemically resistant to acids and bases. In an embodiment, the butadiene copolymer is selected from styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), and combinations thereof. In an embodiment, the butadiene copolymer is styrene-butadiene-styrene (SBS) or a blend of styrene-ethylene-butylene-styrene (SEBS) and styrene-ethylene-propylene-styrene (SEPS). In an embodiment, the blend of SEBS and SEPS has a w/w ratio of about 7:1 to about 10:1. In an embodiment, SBS has a first glass transition temperature of about −115° C. to about −100° C. and a second glass transition temperature of about 85° C. to about 105° C. and the blend of SEBS and SEPS has a first glass transition temperature of about −50° C. to about −20° C. and a second glass transition temperature of about 85° C. to about 115° C. In an embodiment, the butylene polymer is polyisobutylene. In an embodiment, the polymer film comprises about 75% to about 95% by weight of the butadiene copolymer and about 5.0% to about 25.0% by weight of the butylene polymer. In an embodiment, the polymer film further comprises a resin, an inorganic filler, and/or an antioxidant. In an embodiment, the resin is selected from an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, a copolymer of an aromatic hydrocarbon resin and an aliphatic hydrocarbon resin, a hydrogenated resin or a dicyclopentadiene (DCPD) resin, optionally wherein the resin is selected from a C9 aromatic hydrocarbon resin, a C5 aliphatic hydrocarbon resin, and a C5/C9 copolymer resin; and/or the antioxidant is selected from a phenolic compound, a phosphite, a thioester, or dilauryl thiodipropionate, optionally wherein the antioxidant comprises a sterically hindered phenolic compound. In an embodiment, the resin comprises a C9 resin having a softening point between about 100° C. and about 160° C. and/or the inorganic filler is selected from a silicate, talc, a feldspar, a chlorate, alumina, titania, carbon black, nanostructured carbon, and combinations thereof. In an embodiment, the polymer film comprises about 30% by weight to about 50% by weight of the butadiene polymer, about 0.5% by weight to about 15% by weight of the butylene polymer, and about 40% by weight to about 70% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant. In an embodiment, the polymer film comprises an inorganic mineral oxide. In an embodiment, the polymer film comprises about 0.5% by weight to about 4% by weight of the inorganic mineral oxide. In an embodiment, the polymer film is free-standing. In an embodiment, the polymer film is substantially solvent-free. In an embodiment, the tensile strength of the polymer film is about 500 psi to about 750 psi. In an embodiment, the metal substrate is sheet metal. In an embodiment, the polymer film adheres to the metal substrate with a peel adhesion of about 2 oz/in to about 35 oz/in. In an embodiment, the metal substrate is an aluminum substrate. In an embodiment, the metal substrate is polished clad aluminum.
In another aspect, the present disclosure provides a method of making a polymer film, the method comprising: (i) depositing a solution comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. onto a metal substrate; and (ii) evaporating the solvent to form a first polymer film described herein. In an embodiment, the method further comprises: (iii) depositing a solution comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. directly on top of the first polymer film; and (iv) evaporating the solvent to form a second polymer film described herein on top of the first polymer film. In an embodiment, the solution comprises about 60% by weight to about 98% by weight solvent, about 1% by weight to about 15% by weight of the butadiene copolymer, and about 0.01% by weight to about 10% by weight of the butylene polymer. In an embodiment, the solution further comprises a resin, an inorganic filler, an antioxidant, or a combination thereof. In an embodiment, the solution comprises about 65% by weight to about 85% by weight solvent, about 5% by weight to about 15% by weight of the butadiene polymer, about 0.01% by weight to about 5% by weight of the butylene polymer, and about 5% by weight to about 25% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant. In an embodiment, the resin is selected from an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, a copolymer of an aromatic hydrocarbon resin and an aliphatic hydrocarbon resin, a hydrogenated resin, or a dicyclopentadiene (DCPD) resin, optionally wherein the resin is selected from a C9 aromatic hydrocarbon resin, a C5 aliphatic hydrocarbon resin, and a C5/C9 copolymer resin; the antioxidant is selected from a phenolic compound, a phosphite, a thioester, or dilauryl thiodipropionate, optionally wherein the antioxidant comprises a sterically hindered phenolic compound; and/or the inorganic filler is selected from a silicate, talc, a feldspar, a chlorate, alumina, titania, carbon black, nanostructured carbon, and combinations thereof. In an embodiment, the solution comprises an inorganic mineral oxide. In an embodiment, the solution comprises about 0.01% by weight to about 4% by weight of the inorganic mineral oxide.
In yet another aspect, the present disclosure provides a method of making a polymer film, the method comprising: (i) loading a solvent-free composition comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. into compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment; and (ii) extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a first polymer film described herein. In an embodiment, extruding comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment onto a metal substrate to form the first polymer film directly on the metal substrate or extruding comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a free-standing first polymer film. In an embodiment, the method further comprises: (iii) loading a solvent-free composition comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. into compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment; and (iv) extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a second polymer film described herein. In an embodiment, the extruding of (iv) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment onto the first polymer film to form the second polymer film directly on top of the first polymer film, resulting in a multi-layer polymer film; or extruding of (iv) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a free-standing second polymer film which is placed directly on top of the free-standing first polymer film, resulting in a multi-layer polymer film. In an embodiment, the solvent-free composition comprises: about 75% by weight to about 95% by weight of the butadiene polymer and about 5% by weight to about 20% by weight of the butylene polymer; or about 30% by weight to about 50% by weight of the butadiene polymer and about 0.5% by weight to about 15% by weight of the butylene polymer. In an embodiment, the solvent-free composition further comprises a resin, an inorganic filler, an antioxidant, or a combination thereof. In an embodiment, the solvent-free composition comprises about 30% by weight to about 50% by weight of the butadiene polymer, about 0.5% by weight to about 15% by weight of the butylene polymer, and about 40% by weight to about 70% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant. In an embodiment, the resin is selected from an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, a copolymer of an aromatic hydrocarbon resin and an aliphatic hydrocarbon resin, a hydrogenated resin, or a dicyclopentadiene (DCPD) resin, optionally wherein the resin is selected from a C9 aromatic hydrocarbon resin, a C5 aliphatic hydrocarbon resin, and a C5/C9 copolymer resin; the antioxidant is selected from a phenolic compound, a phosphite, a thioester, or dilauryl thiodipropionate, optionally wherein the antioxidant comprises a sterically hindered phenolic compound; and/or the inorganic filler is selected from a silicate, talc, a feldspar, a chlorate, alumina, titania, carbon black, nanostructured carbon, and combinations thereof. In an embodiment, the solvent-free composition comprises an inorganic mineral oxide. In an embodiment, the solvent-free composition comprises about 0.1% by weight to about 8% by weight of the inorganic mineral oxide.
In yet another aspect, the present disclosure provides a method of masking a metal substrate, the method comprising: covering a top surface of the metal substrate with a first polymer film described herein such that the first polymer film is in contact with the top surface of the metal substrate; and heating and/or applying mechanical pressure to the first polymer film, resulting in adhesion of the first polymer film to the top surface of the metal substrate. In an embodiment, the step of covering the top surface of the metal substrate with the first polymer film comprises extruding the first polymer film directly from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment onto the top surface of the metal substrate or extruding the first polymer film from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment and placing the first polymer film onto the top surface of the metal substrate. In an embodiment, extruding the first polymer film from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment comprises: loading a solvent-free composition comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. into the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment; and extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form the first polymer film. In an embodiment, the step of covering the top surface of the metal substrate with the first polymer film comprises depositing a solution comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. onto the top surface of the metal substrate and evaporating the solvent, forming the first polymer film. In an embodiment, the first polymer film comprises two polymer films wherein one film is extruded or deposited directly on top of the other film resulting in a multi-layer first polymer film or wherein one film is placed directly on top of the other film resulting in a multi-layer first polymer film. In an embodiment, the method further comprises: covering a bottom surface of the metal substrate with a second polymer film comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. such that the second polymer film is in contact with the bottom surface of the metal substrate; and heating and/or applying mechanical pressure to the second polymer film, resulting in adhesion of the second polymer film to the bottom surface of the metal substrate. In an embodiment, the step of covering the bottom surface of the metal substrate with the second polymer film comprises extruding the second polymer film directly from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment onto the bottom surface of the metal substrate or extruding the second polymer film from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment and placing the second polymer film onto the bottom surface of the metal substrate. In an embodiment, extruding the second polymer film from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment comprises: loading a solvent-free composition comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. into the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment; and extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form the second polymer film. In an embodiment, the step of covering the bottom surface of the metal substrate with the second polymer film comprises depositing a solution comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C. onto the bottom surface of the metal substrate and evaporating the solvent, forming the second polymer film. In an embodiment, the second polymer film comprises two polymer films wherein one film is extruded or deposited directly on top of the other film resulting in a multi-layer second polymer film or wherein one film is placed directly on top of the other film resulting in a multi-layer second polymer film. In an embodiment, the method is preceded by the step of cleaning and/or chemically treating a top surface and a bottom surface of the metal substrate.
In yet another aspect, the present disclosure provides a method of chemically processing a metal substrate, comprising: chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a metal substrate masked with the polymer film described herein; chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a metal substrate masked with a polymer film made by the method described herein; or chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a masked metal substrate made by the method described herein.
In yet another aspect, the present disclosure provides a method of electrochemically processing a metal substrate, comprising: anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a metal substrate masked with the polymer film described herein; anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a metal substrate masked with a polymer film made by the method described herein; or anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a masked metal substrate made by the method described herein.
In yet another aspect, the present disclosure provides a metal substrate comprising an adhered maskant, wherein: the maskant comprises the polymer film described herein; or the maskant comprises the polymer film made by the method described herein.
In yet another aspect, the present disclosure provides a masked metal substrate made by the method described herein.
While embodiments encompassing the general inventive concepts may take diverse forms, various embodiments will be described herein, with the understanding that the present disclosure is to be considered merely exemplary, and the general inventive concepts are not intended to be limited to the disclosed embodiments.
Unless otherwise noted, terms are to be understood according to conventional usage by those of ordinary skill in the relevant art.
The abbreviations used herein have their conventional meaning within the chemical and biological arts. The chemical structures and formulae set forth herein are constructed according to the standard rules of chemical valency known in the chemical arts.
The term “about” used in the context of a numeric value indicates a range of +/−10% of the numeric value, unless expressly indicated otherwise.
Embodiments of the disclosure set forth herein include polymer films with low glass transition temperatures such that the polymer films can adhere to a metal substrate upon applying heat and mechanical pressure. Other embodiments include methods of using the disclosed polymer films as maskants for metal substrates. Still other embodiments of the disclosure include solutions for making the polymer films. Additional embodiments of the disclosure are also discussed herein.
In one aspect, the present disclosure provides a polymer film comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C., wherein the butadiene copolymer and butylene polymer are oriented such that the polymer film has a first microstructure. In an embodiment, the microstructure of the polymer film is determined by the method used to form the film. Although not wishing to be limited by theory, it is believed that the blocks of the butadiene copolymer segregate amongst each other to form a preferred orientation, wherein the preferred orientation leads to the development of the first microstructure. In an embodiment, the polymer film having a first microstructure does not substantially adhere to the surface of a substrate. In an embodiment, if the substrate having a polymer film with a first microstructure on top is picked up, the polymer film would fall off of the substrate. In an embodiment, the substrate is a metal substrate.
In another aspect, the present disclosure provides a polymer film comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C., wherein the polymer film does not adhere to the surface of a substrate. In an embodiment, the polymer film does not substantially adhere to the surface of a substrate. In an embodiment, if the substrate having a polymer film on top is picked up, the polymer film would fall off of the substrate. In an embodiment, if the substrate having a polymer film on top undergoes mechanical and/or chemical processing, the polymer film would fall off of the substrate. In an embodiment, the substrate is a metal substrate.
In an embodiment, the low glass transition temperature of the butadiene polymer and the butylene polymer leads to a polymer film that has high mobility at elevated temperatures. In an embodiment, the polymer film does not comprise solvent. In an embodiment, the polymer film is substantially or completely free of volatile organic compounds (VOCs).
In an embodiment, the butadiene copolymer is a block copolymer. In an embodiment, the butadiene copolymer is selected from styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), and combinations thereof.
In an embodiment, the butadiene copolymer is SBS. In an embodiment, the SBS has a first glass transition temperature of about −115° C. to about −100° C. and a second glass transition temperature of about 85° C. to about 105° C. In an embodiment, the SBS has a first glass transition temperature of about −107° C. and a second glass transition temperature of about 100° C.
In another embodiment, the butadiene copolymer is a blend of SEBS and SEPS. In an embodiment, the w/w ratio of SEBS to SEPS is about 20:1, 18:1, 16:1, 14:1, 12:1, 10:1, 9:1, 8:1, 6:1, 2:1, 1:1, 1:2, 1:4, 1:6, 1:8, 1:9, 1:10, 1:12, 1:14, 1:16, 1:18, or 20:1. In an embodiment, the w/w ratio of SEBS to SEPS is about 11:1, 10:1, 9:1, 8:1 or 7:1. In an embodiment, the w/w ratio of SEBS to SEPS is about 9:1. In an embodiment, the glass transition temperature of the blend of SEBS and SEPS blend is about −50° C. to about 107° C. In an embodiment, the blend of SEBS and SEPS has a first glass transition temperature of about −50° C. to about −20° C. and a second glass transition temperature of about 80° C. to about 120° C. or about 95° C. to about 107° C. In an embodiment, the first glass transition temperature is for the butadiene/propylene blocks of the copolymer and the second glass transition temperature is for the ethylene/styrene blocks of the copolymer.
In an embodiment, the blend of SEBS and SEPS is a “high melt-flow” material. In an embodiment, a high melt-flow material is a material that behaves similarly to a fluid under increased temperature and/or pressure. In an embodiment, the SBS, SEBS, and/or SEPS provides a polymer film with a high melt-flow. Although not wishing to be limited by theory, it is believed that the molecular weight of the SBS, SEBS, and/or SEPS used in the polymer film influences the melt-flow of the resulting polymer film. In an embodiment, the use of a low molecular weight SBS, SEBS, and/or SEPS in the polymer film provides a film with high melt-flow. In an embodiment, the molecular weight of SBS, SEBS, and/or SEPS is less than about 50 kDa, less than about 45 kDa, less than about 40 kDa, less than about 35 kDa, less than about 30 kDa, less than about 25 kDa, less than about 20 kDa, less than about 15 kDa, less than about 10 kDa, or less than about 5 kDa. In an embodiment, the molecular weight of SBS, SEBS, and/or SEPS is between about 5 kDa and about 25 kDa, about 5 kDa and about 20 kDa, about 5 kDa and about 15 kDa, about 8 kDa and about 15 kDa, about 8 kDa and about 12 kDa, or about 8 kDa and about 10 kDa. In an embodiment, the length of the blocks of repeating monomers in the butadiene copolymer affects the melt-flow of the resulting polymer film. In an embodiment, the branching of the butadiene copolymer affects the melt-flow of the resulting polymer film.
Although not wishing to be limited by theory, it is believed that the butylene polymer behaves like a plasticizer in the polymer film. Therefore, in some embodiments, the butylene polymer softens the resulting polymer film. In some embodiments, the softening of the polymer film helps the polymer film to flow under high temperature and/or high pressure. In an embodiment, a polymer film with a higher percentage (e.g., % by weight) of the butylene polymer will have lower tensile strength than a comparable polymer film with a lower percentage (e.g., % by weight) of the butylene polymer.
In an embodiment, the butylene polymer is polyisobutylene. In an embodiment, the polyisobutylene has a glass transition temperature of about −78° C. to about −60° C. In an embodiment, the polyisobutylene is BASF Oppanol polyisobutylene (PIB). In an embodiment, the polyisobutylene is medium molecular weight BASF Oppanol PIB. In an embodiment, the polyisobutylene is a SeaLand Chemical TPC Group polyisobutylene. In an embodiment, the polyisobutylene is a Lubrizol Solplus polyisobutylene. In an embodiment, the polymer film comprises about 75% to about 95% by weight of the butadiene copolymer and about 5.0% to about 25.0% by weight of the butylene polymer. In an embodiment, the polymer film comprises about 87% by weight of the butadiene copolymer and about 13% by weight of the butylene polymer. In an embodiment, the polymer film comprising the butadiene copolymer and the butylene polymer is a high melt-flow material. Although not wishing to be limited by theory, it is believed that the molecular weight of the butylene polymer used in the polymer film influences the melt-flow of the resulting polymer film. In an embodiment, the use of a low molecular weight butylene polymer in the polymer film provides a film with high melt-flow. In an embodiment, the molecular weight of butylene polymer is less than about 50 kDa, less than about 45 kDa, less than about 40 kDa, less than about 35 kDa, less than about 30 kDa, less than about 25 kDa, less than about 20 kDa, less than about 15 kDa, less than about 10 kDa, or less than about 5 kDa. In an embodiment, the molecular weight of the butylene polymer is between about 5 kDa and about 25 kDa, about 5 kDa and about 20 kDa, about 5 kDa and about 15 kDa, about 8 kDa and about 15 kDa, about 8 kDa and about 12 kDa, or about 8 kDa and about 10 kDa. In an embodiment, the branching of the butylene polymer affects the melt-flow of the resulting polymer film.
In an embodiment, the polymer film is chemically resistant to acids and bases.
In an embodiment, the tensile strength of the polymer film is about 650 psi to about 750 psi. In an embodiment, the tensile strength of the polymer film is about 300 psi to about 750 psi, about 350 psi to about 750 psi, about 350 psi to about 700 psi, about 400 psi to about 700 psi, about 400 psi to about 650 psi, about 450 psi to about 650 psi, about 500 psi to about 650 psi, about 450 psi to about 600 psi, or about 550 psi to about 625 psi.
In an embodiment, the polymer film is a free-standing polymer film. In an embodiment, the free-standing polymer film can be stored and/or handled unsupported. In an embodiment, a polymer film formed on a substrate is still referred to as a free-standing polymer film because, if removed from the substrate, the film can be stored and/or handled unsupported. In another embodiment, the polymer film comprises a release sheet on the top and/or bottom of the polymer film. In an embodiment, the release sheet is used for ease of storing, rolling, and/or handling the polymer film.
In some embodiments, the polymer film further comprises a resin, an inorganic filler, an antioxidant, a mineral oxide, or a combination thereof. In an embodiment, the resin is an aromatic hydrocarbon resin. In an embodiment, the aromatic hydrocarbon resin is a C9 resin. In an embodiment, the resin is an aliphatic hydrocarbon resin. In an embodiment, the resin is a C5 aliphatic hydrocarbon resin. In an embodiment, the resin is a copolymer of an aromatic hydrocarbon resin and an aliphatic hydrocarbon resin. In an embodiment, the resin is a C5/C9 copolymer resin. In an embodiment, the resin is a hydrogenated resin. In an embodiment, the resin is a dicyclopentadiene resins (DCPD) resin. In an embodiment, the resin has a softening point between about 70° C. and about 200° C., about 85° C. and about 180° C., or about 100° C. and about 160° C. In an embodiment, the hydrocarbon resin is a C9 resin with a softening point of between about 70° C. and about 200° C., about 85° C. and about 180° C., or about 100° C. and about 160° C.
In an embodiment, the antioxidant comprises a phenolic antioxidant. In an embodiment, the antioxidant is dilauryl thiodipropionate. In an embodiment, the phenolic antioxidant functions as a primary antioxidant. In an embodiment, the phenolic antioxidant is a hindered phenolic antioxidant. In an embodiment, the antioxidant comprises a phosphite or thioester antioxidant. In an embodiment, the phosphite or thioester antioxidant functions as a secondary antioxidant. In an embodiment, the antioxidant comprises a radical scavenger or metal deactivator. In an embodiment, the radical scavenger or metal deactivator functions as a tertiary antioxidant. In an embodiment, the radical scavenger or metal deactivator is a sterically hindered phenolic antioxidant. In an embodiment, the radical scavengers or metal deactivator is a sterically-hindered phenol with bound sulfur or copper chelation.
In an embodiment, the polymer film comprises an inorganic filler. In an embodiment, the inorganic filler comprises a silicate, talc, a feldspar, a chlorate, alumina, or titania, each of which can be optionally functionalized with one or more organic groups. In another embodiment, the inorganic filler comprises inorganic carbon. In an embodiment, the inorganic carbon comprises graphite, carbon black, and/or nanostructured carbon. In an embodiment, the polymer film comprises about 20% by weight to about 85% by weight, about 25% by weight to about 80% by weight, about 30% by weight to about 75% by weight, about 35% by weight to about 70% by weight, about 40% by weight to about 65% by weight, about 45% by weight to about 60% by weight, about 45% by weight to about 55% by weight, or about 30% by weight to about 50% by weight of the inorganic filler.
In an embodiment, the polymer film has a tensile strength of between about 50 psi to about 1500 psi, about 50 psi to about 1400 psi, about 100 psi to about 1400 psi, about 100 psi to about 1300 psi, about 150 psi to about 1300 psi, about 150 psi to about 1200 psi, about 200 psi to about 1200 psi, about 200 psi to about 1100 psi, about 250 psi to about 1100 psi, about 250 psi to about 1000 psi, about 300 psi to about 1000 psi, about 300 psi to about 900 psi, about 350 psi to about 850 psi, about 400 psi to about 800 psi, about 450 psi to about 750 psi, about 500 psi to about 700 psi, about 550 psi to about 700 psi, or about 600 psi to about 700 psi. In an embodiment, a polymer film comprising between about 35% by weight to about 45% by weight of inorganic filler has a tensile strength of at least 600 psi. In an embodiment, a polymer film comprising between about 35% by weight to about 45% by weight of inorganic filler has a tensile strength of between about 600 psi and 700 psi. In an embodiment, an increase in the % by weight of filler in the polymer film increases the tensile strength of the polymer film.
In an embodiment, the polymer film has a % elongation of between about 0.5% to about 15%, about 0.5% to about 14%, about 0.5% to about 13%, about 0.5% to about 12%, about 0.5% to about 11%, about 0.5% to about 10%, about 1% to about 10%, about 1% to about 9%, about 1% to about 8%, about 1% to about 7%, about 2% to about 7%, about 2% to about 6%, about 3% to about 6%, or about 3% to about 5%. In an embodiment, a polymer film comprising between about 35% by weight to about 45% by weight of inorganic filler has a % elongation of at least 3%. In an embodiment, a polymer film comprising between about 35% by weight to about 45% by weight of inorganic filler has a % elongation of between about 3% and 5%. In an embodiment, an increase in the % by weight of filler in the polymer film increases the % elongation of the polymer film.
In an embodiment, the polymer film comprises a mineral oxide. In an embodiment, the mineral oxide is an inorganic mineral oxide. In an embodiment, the polymer film comprises about 0.01% by weight to about 10% by weight, about 0.05% by weight to about 8% by weight, about 0.1% by weight to about 6% by weight, about 0.5% by weight to about 4% by weight, or about 1.0% by weight to about 2% by weight of the inorganic mineral oxide. In an embodiment, the inorganic mineral oxide is magnesium oxide or zinc oxide. In one embodiment, the inorganic mineral oxide does not function as a filler. In an embodiment, the inorganic mineral oxide increases the stiffness (clastic modulus) of the polymer film, increases the tensile strength of the polymer film, and/or increases the chemical resistance of the polymer film. In an embodiment, the increase in elastic modulus, tensile strength, and/or chemical resistance is an increase when compared to a similar polymer film that does not comprise the inorganic mineral oxide. In an embodiment, the inorganic mineral oxide promotes the crosslinking of the polymer film.
In an embodiment, a solvent is applied to one side of the polymer film as a tackifier which aids in adhering the polymer film to the substrate. In an embodiment, the solvent comprises an organic solvent.
In some embodiments, the polymer film has a high melt-flow such that it has the ability to “flow” and/or reorient under the application of high temperature and/or high pressure. In an embodiment, the polymer film with a high melt-flow has a first microstructure such that the first microstructure does not permit the polymer film to substantially adhere to the surface of a substrate. In an embodiment, the polymer film has a high melt-flow such that it has the ability to “flow” and therefore adopts a second microstructure when in contact with a substrate under high temperature and/or high pressure. In an embodiment, the second microstructure has increased adhesion to the substrate. In an embodiment, the polymer film has a high melt-flow such that, when it is placed in contact with a substrate under high temperature and/or high pressure, the polymer film adheres to the substrate. In an embodiment, the application of high temperature and/or high pressure is performed using an autoclave. In an embodiment, the polymer film remains adhered to the substrate after the application of high temperature and/or high pressure is stopped. In an embodiment, the polymer film adheres to the substrate with sufficient strength that it does not fall off of the substrate if the substrate is picked up and manipulated. In an embodiment, the polymer film adheres to the substrate with sufficient strength that it does not fall off during chemical and/or mechanical processing of the substrate. In an embodiment, the substrate is a metal substrate. In an embodiment, the metal substrate is sheet metal.
In an embodiment, the melt-flow of the polymer film is determined by measuring the melt-flow index of the polymer film. In an embodiment, the melt-flow index of the polymer film is greater than about 5 grams/10 minutes, about 10 grams/10 minutes, about 15 grams/10 minutes, about 20 grams/10 minutes, about 25 grams/10 minutes, about 30 grams/10 minutes, about 35 grams/10 minutes, about 40 grams/10 minutes, about 45 grams/10 minutes, about 50 grams/10 minutes, about 55 grams/10 minutes, about 60 grams/10 minutes, about 65 grams/10 minutes, about 70 grams/10 minutes, or about 75 grams/10 minutes for a polymer film sample having a weight of about 1 kg when measured at a temperature of about 190° C. In an embodiment, the melt-flow index of the polymer film is at least about 30 grams/10 minutes for a polymer film sample having a weight of about 1 kg when measured at a temperature of about 190° C. Typical maskant polymers have considerably lower melt-flow indexes than the polymer films of the present disclosure, on the order of about 6 grams/10 minutes for a 5 kg sample when measured at a temperature of about 230° C.
In an embodiment, following the application of high temperature and/or high pressure, the polymer remains adhered to the substrate with a peel adhesion of about 2 oz/in to about 35 oz/in, about 4 oz/in to about 30 oz/in, about 5 oz/in to about 25 oz/in, about 10 oz/in to about 25 oz/in, about 2 oz/in to about 25 oz/in, about 5 oz/in to about 25 oz/in, or about 10 oz/in to about 20 oz/in. In an embodiment, the peel adhesion of the polymer film adhered to the substrate changes with chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 2 oz/in to about 12 oz/in before chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 7 oz/in before chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 10 oz/in to about 20 oz/in after chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 15 oz/in after chemical processing. In another embodiment, the peel adhesion of the polymer film adhered to the substrate does not significantly change with chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 2 oz/in to about 25 oz/in before chemical processing and retains a peel adhesion of about 2 oz/in to about 25 oz/in after chemical processing. In an embodiment, the polymer film is adhered to the substrate with a peel adhesion of about 10 oz/in to about 15 oz/in before chemical processing and retains a peel adhesion of about 10 oz/in to about 15 oz/in after chemical processing. In an embodiment, the polymer film comprises a blend of SEBS with SEPS and a butylene polymer wherein the polymer film is adhered to the substrate with a peel adhesion of about 10 oz/in to about 15 oz/in before chemical processing and retains a peel adhesion of about 10 oz/in to about 15 oz/in after chemical processing. In an embodiment, the peel adhesion is measured on a metal substrate. In an embodiment, the peel adhesion is measured on a sheet metal substrate. In an embodiment, the peel adhesion is measured on an aluminum substrate. In embodiment, the peel adhesion is measured on a polished clad aluminum substrate.
In an embodiment, the substrate is a metal substrate. In an embodiment, the metal substrate is an aluminum substrate. In an embodiment, the metal substrate is polished clad aluminum. In an embodiment, the metal substrate is heat-treated aluminum. In an embodiment, the metal substrate is an aerospace component. In an embodiment, the polymer film functions as a maskant to protect the metal substrate during chemical and/or mechanical processing. In an embodiment, the maskant protects the metal substrate during forming and/or scribing. Therefore, in an embodiment, the maskant is applied to the metal substrate before forming and/or scribing. In an embodiment, the polymer film functions as a maskant to protect the metal substrate during forming and/or scribing, chemical processing, and optional further treatment steps. In an embodiment, the optional further treatment steps comprise drilling and/or routing. In an embodiment, the maskant protects an aerospace component during the forming, scribing, chemical processing, and optional further treatment steps necessary to fabricate aerospace components. Therefore, in an embodiment, the maskant remains adhered to the metal substrate during the mechanical processing, chemical processing, forming, scribing, and/or optional further treatment of the metal substrate. In an embodiment, the metal substrate is demasked following the forming, scribing, chemical processing, and optional further treatment steps.
In an embodiment, the polymer film maskant is removed from the metal substrate by hand. Although not wishing to be limited by theory, it is believed that a polymer film maskant having an adhesion of about 4 oz/in to about 30 oz/in, preferably about 6 oz/in to about 20 oz/in, and more preferably about 10 oz/in to about 14 oz/in can be removed by hand. In an embodiment, the polymer film maskant is removed from the metal substrate by stripping the maskant from the surface of the metal substrate using a solvent. In an embodiment, the polymer film maskant is removed from the metal substrate by burning the maskant off of the surface of the metal substrate.
In another aspect, the present disclosure provides a solution from which the polymer film described elsewhere herein is made.
In an embodiment, the solution comprises an organic solvent. In an embodiment, the solvent comprises a halogenated organic solvent. In an embodiment, the halogenated organic solvent comprises a halogenated alkene. In an embodiment, the halogenated organic solvent comprises a chlorinated alkene. In an embodiment, the halogenated organic solvent comprises perchloroethylene. In another embodiment, the organic solvent comprises an aromatic solvent. In an embodiment, the aromatic solvent comprises toluene, xylene, cumene, and/or pseudocumene. In an embodiment, the aromatic solvent comprises toluene or xylene. In another embodiment, the aromatic solvent comprises solvent naphtha. In an embodiment, the aromatic solvent comprises Aromatic 100. In another embodiment, the aromatic solvent comprises a halogenated aromatic solvent. In an embodiment, the halogenated aromatic solvent comprises parachlorobenzotrifluoride. In an embodiment, the solution comprises about 50% by weight to about 90% by weight, about 55% by weight to about 85% by weight, about 60% by weight to about 80% by weight, about 65% by weight to about 80% by weight, or about 70% by weight to about 80% by weight organic solvent. In an embodiment, the solution comprises about 76% by weight organic solvent. In another embodiment, the solution comprises about 75% by weight to about 98% by weight, about 80% by weight to about 98% by weight, about 85% by weight to about 98% by weight, about 90% by weight to about 98% by weight, or about 90% by weight to about 95% by weight organic solvent. In an embodiment, the solution comprises about 92.5% by weight organic solvent.
In an embodiment, the solution comprises an aqueous solvent. In an embodiment, the aqueous solvent is water. In an embodiment, the solution comprises less than about 10% by weight, about 9% by weight, about 8% by weight, about 7% by weight, about 6% by weight, about 5% by weight, about 4% by weight, about 3% by weight about 2% by weight, about 1% by weight, about 0.5% by weight, about 0.25% by weight, or about 0.1% by weight water.
In an embodiment, the solution comprises a butadiene copolymer described elsewhere herein. In an embodiment, the butadiene copolymer is SBS. In an embodiment, the butadiene copolymer is a blend of SEBS and SEPS. In an embodiment, solution comprises about 1% by weight to about 25% by weight, about 1% by weight to about 20% by weight, about 1% by weight to about 15% by weight, about 4% by weight to about 15% by weight, about 6% by weight to about 12% by weight, about 1% by weight to about 10% by weight, or about 4% by weight to about 8% by weight of the butadiene copolymer. In an embodiment, the solution comprises about 6.5% by weight of the butadiene copolymer. In another embodiment, the solution comprises about 9% by weight or about 9.5% by weight of the butadiene copolymer.
In an embodiment, the solution comprises a butylene polymer described elsewhere herein. In an embodiment, the butylene polymer is polyisobutylene. In an embodiment, the solution comprises about 0.001% by weight to about 18% by weight, about 0.001% by weight to about 16% by weight, about 0.001% by weight to about 14% by weight, about 0.001% by weight to about 12% by weight, about 0.001% by weight to about 10% by weight, about 0.001% by weight to about 8% by weight, about 0.001% by weight to about 6% by weight, about 0.001% by weight to about 4% by weight, about 0.001% by weight to about 2% by weight, about 0.01% by weight to about 2% by weight, or about 0.1% by weight to about 2% by weight polyisobutylene. In an embodiment, the solution comprises about 1% by weight polyisobutylene.
In an embodiment, the solution comprises a resin, an inorganic filler, and/or an antioxidant described elsewhere herein. In an embodiment, the solution comprises about 0.1% by weight to about 90% by weight, about 0.1% by weight to about 80% by weight, about 0.1% by weight to about 70% by weight, about 0.1% by weight to about 60% by weight, about 0.1% by weight to about 50% by weight, about 0.1% by weight to about 40% by weight, about 0.1% by weight to about 30% by weight, about 0.1% by weight to about 20% by weight, about 1% by weight to about 20% by weight, or about 5% by weight to about 15% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant.
In an embodiment, the solution comprises between about 0.01% by weight to about 15% by weight, about 0.05% by weight to about 12% by weight, about 0.05% by weight to about 10% by weight, about 0.1% by weight to about 8% by weight, about 0.1% by weight to about 6% by weight, about 0.1% by weight to about 4% by weight, or about 0.5% by weight to about 2% by weight of the resin. In an embodiment, the solution comprises about 1% by weight of the resin. In an embodiment, the solution comprises between about 1% by weight to about 40% by weight, about 1% by weight to about 35% by weight, about 1% by weight to about 30% by weight, about 1% by weight to about 25% by weight, about 1% by weight to about 20% by weight, about 5% by weight to about 20% by weight, or about 5% by weight to about 15% by weight of the inorganic filler. In an embodiment, the solution comprises about 12% by weight of the inorganic filler. In an embodiment, the solution comprises between about 0.001% by weight to about 10% by weight, about 0.001% by weight to about 8% by weight, about 0.001% by weight to about 6% by weight, about 0.001% by weight to about 4% by weight, about 0.001% by weight to about 4% by weight, about 0.001% by weight to about 2% by weight, about 0.005% by weight to about 1% by weight, about 0.01% by weight to about 1% by weight, or about 0.05% by weight to about 1% by weight of the antioxidant. In an embodiment, the solution comprises about 0.1% by weight of the antioxidant.
In an embodiment, the solution comprises a metal oxide described elsewhere herein. In an embodiment, the solution comprises about 0.01% by weight to about 20% by weight, about 0.01% by weight to about 15% by weight, about 0.01% by weight to about 10% by weight, about 0.01% by weight to about 5% by weight, about 0.01% by weight to about 2.5% by weight, about 0.01% by weight to about 1% by weight, about 0.1% by weight to about 1% by weight, or about 0.1% by weight to about 0.5% by weight of the metal oxide. In an embodiment, the solution comprises about 0.35% by weight of the mineral oxide.
In an embodiment, the solution described above is deposited onto a substrate and the solvent is allowed to evaporate, forming a polymer film. In an embodiment, the substrate is a metal substrate. In an embodiment, after solution deposition and solvent evaporation, the polymer film is substantially free or completely free of solvent. In an embodiment, “substantially free of solvent” as used herein means a polymer film (maskant) comprising less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or less than 0.5% solvent. In an embodiment, the polymer film can be peeled from the substrate to provide a free-standing polymer film.
In yet another aspect, the present disclosure provides a solvent-free composition from which the polymer film described elsewhere herein is made. In an embodiment, the polymer film is a free-standing polymer film. In an embodiment, the polymer film is produced via plastic compounding.
In an embodiment, the solvent-free composition comprises a butadiene copolymer described elsewhere herein. In an embodiment, the butadiene copolymer is SBS. In an embodiment, the butadiene copolymer is a blend of SEBS and SEPS. In an embodiment, the composition comprises about 5% by weight to about 90% by weight, about 10% by weight to about 85% by weight, about 15% by weight to about 80% by weight, about 20% by weight to about 75% by weight, about 25% by weight to about 70% by weight, about 30% by weight to about 65% by weight, about 30% by weight to about 60% by weight, about 30% by weight to about 50% by weight, or about 30% by weight to about 45% by weight of the butadiene copolymer. In an embodiment, the composition comprises about 41% by weight of the butadiene copolymer. In an embodiment, the composition comprises about 36% by weight of the butadiene copolymer.
In an embodiment, the solvent-free composition comprises a butylene polymer described elsewhere herein. In an embodiment, the butylene polymer is polyisobutylene. In an embodiment, the composition comprises about 0.001% by weight to about 18% by weight, about 0.001% by weight to about 16% by weight, about 0.001% by weight to about 14% by weight, about 0.01% by weight to about 14% by weight, about 0.01% by weight to about 12% by weight, about 0.1% by weight to about 12% by weight, about 0.1% by weight to about 10% by weight, about 0.1% by weight to about 8% by weight, about 1% by weight to about 8% by weight, about 1% by weight to about 6% by weight, or about 2% by weight to about 6% by weight polyisobutylene. In an embodiment, the composition comprises about 4% by weight polyisobutylene.
In an embodiment, the solvent-free composition comprises a resin, an inorganic filler, and/or an antioxidant described elsewhere herein. In an embodiment, the composition comprises between about 1% by weight to about 90% by weight, about 5% by weight to about 85% by weight, about 10% by weight to about 80% by weight, about 15% by weight to about 75% by weight, about 20% by weight to about 70% by weight, about 25% by weight to about 65% by weight, about 35% by weight to about 65% by weight, about 45% by weight to about 65% by weight, or about 50% by weight to about 60% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant.
In an embodiment, the solvent-free composition comprises between about 20% by weight to about 85% by weight, about 25% by weight to about 80% by weight, about 30% by weight to about 75% by weight, about 35% by weight to about 70% by weight, about 40% by weight to about 65% by weight, about 45% by weight to about 60% by weight, or about 45% by weight to about 55% by weight of the inorganic filler. In an embodiment, the solvent-free composition comprises about 50% by weight of the inorganic filler. In an embodiment, the solvent-free composition comprises between about 0.1% by weight to about 15% by weight, about 0.5% by weight to about 12% by weight, about 1% by weight to about 10% by weight, about 1.5% by weight to about 8% by weight, about 2% by weight to about 6% by weight, or about 2% by weight to about 4% by weight of a resin. In an embodiment, the solvent-free composition comprises about 3% by weight or about 3.5% by weight of a resin. In an embodiment, the solvent-free composition comprises between about 0.01% by weight to about 15% by weight, about 0.01% by weight to about 10% by weight, about 0.01% by weight to about 6% by weight, about 0.05% by weight to about 4% by weight, about 0.05% by weight to about 2% by weight, about 0.1% by weight to about 2% by weight, or about 0.1% by weight to about 1% by weight of the antioxidant. In an embodiment, the solvent-free composition comprises about 0.5% by weight or about 0.6% by weight of the antioxidant.
In an embodiment, the solvent-free composition comprises a mineral oxide described elsewhere herein. In an embodiment, the solvent-free composition comprises between about 0.01% by weight to about 10% by weight, about 0.05% by weight to about 8% by weight, about 0.1% by weight to about 6% by weight, about 0.5% by weight to about 4% by weight, or about 1.0% by weight to about 2% by weight of the mineral oxide. In an embodiment, the solvent-free composition comprises about 1.5% by weight of the mineral oxide. In an embodiment, the mineral oxide functions as a crosslink promoter.
In an embodiment, the solvent-free composition comprises a minimal amount of an aqueous solvent. In an embodiment, the aqueous solvent is water. In an embodiment, the solution comprises less than about 10% by weight, about 9% by weight, about 8% by weight, about 7% by weight, about 6% by weight, about 5% by weight, about 4% by weight, about 3% by weight about 2% by weight, about 1% by weight, about 0.5% by weight, about 0.25% by weight, or about 0.1% by weight water. Although not wishing to be limited by theory, it is believed that a minimal amount of an aqueous solvent may prevent the polymer film formed from the solvent-free composition from cracking when it is manipulated.
In an embodiment, the previously described solvent-free composition is loaded into compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment and is extruded to form the polymer film described elsewhere herein. In an embodiment, after extrusion from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment, the polymer film is substantially or completely free of solvent.
Methods of Making a Polymer Film from the Solution
In yet another aspect, the present disclosure provides a method of making a polymer film, the method comprising:
In an embodiment, the butadiene copolymer and butylene polymer are oriented in the first polymer film such that the first polymer film has a first microstructure. In an embodiment, the first polymer film having the first microstructure is not adhered to the substrate. In another embodiment, the first polymer film formed from the butadiene copolymer and butylene polymer is not adhered to the substrate. In an embodiment, the first polymer film does not adhere to the substrate sufficiently for the substrate to be chemically and/or mechanically processed without the polymer film detaching and/or falling off of the substrate. In an embodiment, when high temperature and/or high pressure is applied to the first polymer film, it adheres to the surface of the substrate. In an embodiment, when high temperature and/or high pressure is applied to the first polymer film, it adopts a second microstructure with increased adhesion to the surface of the substrate and thus the first polymer film adheres to the substrate. In an embodiment, the first polymer film formed from (i) and (ii) is a single layer polymer film.
In an embodiment, depositing of (i) comprises spraying the solution onto the substrate or dipping the substrate into the solution.
In an embodiment, the method further comprises:
In an embodiment, the butadiene copolymer and butylene polymer are oriented in the second polymer film such that the second polymer film has a first microstructure. In an embodiment, the deposition of the second polymer film formed on top of the first polymer film results in a multi-layer polymer film.
In an embodiment, depositing of (iii) comprises spraying the solution onto the first polymer film or dipping the substrate comprising the first polymer film into the solution.
In an embodiment, the substrate of (i) and/or (iii) comprises a metal substrate. The metal substrate is described elsewhere herein.
In an embodiment, the first polymer film and/or the second polymer film is substantially free of solvent.
In an embodiment, the butadiene copolymer in the solution of (i) and/or (iii) is described elsewhere herein. In an embodiment, the butylene polymer in the solution of (i) and/or (iii) is described elsewhere herein. In an embodiment, the solvent in the solution of (i) and/or (iii) is described elsewhere herein. In an embodiment, the solution of (i) and/or (iii) further comprises a resin, an inorganic filler, an antioxidant, or a combination thereof. In an embodiment, the resin, the inorganic filler, and the antioxidant are described elsewhere herein. In an embodiment, the solution of (i) and/or (iii) further comprises a metal oxide. In an embodiment, the metal oxide is described elsewhere herein.
In an embodiment, the solution of (i) and/or (iii) comprises about 80% by weight to about 98% by weight solvent, about 1% by weight to about 15% by weight of the butadiene copolymer, and about 0.01% by weight to about 10% by weight of the butylene polymer. In another embodiment, the solution of (i) and/or (iii) further comprises a resin, an inorganic filler, an antioxidant, a mineral oxide, or a combination thereof and the solution of (i) or (iii) comprises about 65% by weight to about 85% by weight solvent, about 5% by weight to about 15% by weight of the butadiene polymer, about 0.01% by weight to about 5% by weight of the butylene polymer, about 0.01% by weight to about 1% by weight of the mineral oxide, and about 5% by weight to about 25% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant.
Methods of Making a Polymer Film from the Solvent-Free Composition
In yet another aspect, the present disclosure provides a method of making a polymer film, the method comprising:
In an embodiment, the extruder is a twin-screw extruder. In an embodiment, the extruder is a blown film extrusion machine. In an embodiment, the mixer is a high intensity mixer. In an embodiment, the milling equipment is a two-roll mill. In an embodiment, the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment known for use in plastic compounding.
In an embodiment, the butadiene copolymer and butylene polymer are oriented in the first polymer film such that the first polymer film has a first microstructure. In an embodiment, the first polymer film formed from (i) and (ii) is a single layer polymer film.
In an embodiment, extruding of (ii) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment onto a substrate to form the first polymer film directly on the substrate. In another embodiment, extruding of (ii) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a free-standing first polymer film. In an embodiment, the free-standing first polymer film is placed on top of a substrate. In an embodiment, the first polymer film having the first microstructure does not adhere to the substrate. In another embodiment, the first polymer film formed from the butadiene copolymer and butylene polymer does not adhere to the substrate. In an embodiment, the first polymer film does not adhere to the substrate sufficiently for the substrate to be chemically and/or mechanically processed without the polymer film detaching and/or falling off of the substrate. In an embodiment, when high temperature and/or high pressure is applied to the first polymer film, it adheres to the surface of the substrate. In an embodiment, when high temperature and/or high pressure is applied to the first polymer film, it adopts a second microstructure with increased adhesion to the surface of the substrate and thus the first polymer film adheres to the substrate. In an embodiment, a solvent is applied to one side of the polymer film as a tackifier which aids in adhering the polymer film to the substrate. In an embodiment, the solvent comprises an organic solvent. In an embodiment, the substrate is a metal substrate. The metal substrate is described elsewhere herein.
In an embodiment, the method further comprises:
In an embodiment, the extruder is a twin-screw extruder. In an embodiment, the extruder is a blown film extrusion machine. In an embodiment, the mixer is a high intensity mixer. In an embodiment, the milling equipment is a two-roll mill. In an embodiment, the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment known for use in plastic compounding.
In an embodiment, the butadiene copolymer and butylene polymer are oriented in the second polymer film such that the second polymer film has a first microstructure.
In an embodiment, extruding of (iv) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment onto the first polymer film to form the second polymer film directly on top of the first polymer film, resulting in a multi-layer polymer film. In an embodiment, the multi-layer polymer film is placed on top of a substrate. In another embodiment, extruding of (iv) comprises extruding the composition from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment to form a free-standing second polymer film. In an embodiment, the free-standing second polymer film is placed directly on top of the free-standing first polymer film, resulting in a multi-layer polymer film.
In an embodiment, the first polymer film and the second polymer film of the multi-layer polymer film interact under elevated temperatures and/or increased pressure such that they adhere or stick to each other. Although not wishing to be limited by theory, the “interaction” or “bonding” between the two polymer films of the multi-layer polymer film can be approximated by a combination of polar and non-polar interactions, generally grouped under the term “surface energy.” Therefore, in an embodiment, the first polymer film and the second polymer film of a multi-layer polymer film are designed to have similar surface energies.
In an embodiment, the multi-layer polymer film is placed on top of a substrate. In an embodiment, a solvent is applied to one side of the multi-layer polymer film as a tackifier which aids in adhering the multi-layer polymer film to the substrate. In an embodiment, the solvent comprises an organic solvent. In an embodiment, the substrate is a metal substrate. The metal substrate is described elsewhere herein.
In an embodiment, the butadiene copolymer in the composition of (i) and/or (iii) is described elsewhere herein. In an embodiment, the butylene polymer in the composition of (i) and/or (iii) is described elsewhere herein. In an embodiment, the composition of (i) and/or (iii) further comprises a resin, an inorganic filler, an antioxidant, or a combination thereof. In an embodiment, the resin, the inorganic filler, and the antioxidant are described elsewhere herein. In an embodiment, the composition of (i) and/or (iii) further comprises a mineral oxide. In an embodiment, the mineral oxide is described elsewhere herein. In an embodiment, the composition of (i) and/or (iii) comprises about 30% by weight to about 50% by weight of the butadiene copolymer, about 0.5% by weight to about 15% by weight of the butylene polymer, about 0.5% by weight to about 5% by weight of the mineral oxide, and about 40% by weight to about 70% by weight of the combination of the resin, the inorganic filler, and/or the antioxidant.
In yet another aspect, the present disclosure provides a method of masking a substrate, the method comprising: covering a top surface of the substrate with a first polymer film comprising two or more chemically resistant polymers such that the first polymer film is in contact with the top surface of the substrate; and heating and/or applying mechanical pressure to the first polymer film, resulting in adhesion of the first polymer film to the top surface of the substrate.
In an embodiment, the substrate is a metal substrate.
In an embodiment, the step of covering the top surface of the substrate with the first polymer film comprises extruding the first polymer film directly from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment onto the top surface of the substrate. In an embodiment, the solvent-free composition described above is loaded into the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment and the first polymer is extruded from the compounding machinery directly onto the top surface of the substrate.
In another embodiment, the step of covering the top surface of the substrate with the first polymer film comprises placing the first polymer film formed from the solution described above directly onto the top surface of the substrate.
In another embodiment, the step of covering the top surface of the substrate with the first polymer film comprises placing the first polymer film formed from the solvent-free composition described above directly onto the top surface of the substrate. In an embodiment, the step of covering the top surface of the substrate with the first polymer film comprises loading the solvent-free composition described above into compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment; extruding the first polymer film from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment; and placing the first polymer film directly onto the top surface of the substrate.
In yet another embodiment, the step of covering the top surface of the substrate with the first polymer film comprises depositing a solution comprising two or more chemically resistant polymers onto the top surface of the substrate and evaporating the solvent, forming the first polymer film. In an embodiment, the solution is described above.
In an embodiment, heating and/or applying mechanical pressure to the first polymer film in contact with the metal substrate provides increased adhesion of the first polymer film to the substrate. In an embodiment, the first polymer film adheres to the substrate and remains adhered during chemical and/or mechanical processing of the substrate. In an embodiment, the first polymer film has a first microstructure and, upon heating and/or applying mechanical pressure to the first polymer film in contact with the substrate, the first polymer film adopts a second microstructure. In an embodiment, the second microstructure has increased adhesion to the substrate.
In an embodiment, the first polymer film comprises two polymer films with one film extruded from compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment directly on top of the other film. In another embodiment, the first polymer film comprises two polymer films with one film laid directly on top of the other film. In another embodiment, the first polymer film comprises two polymer films wherein one film is formed by depositing a solution comprising two or more chemically resistant polymers directly on top of the other film and then evaporating the solvent to form one polymer film laid directly on top of the other film. In an embodiment, the first polymer film and the second polymer film of the multi-layer polymer film interact under elevated temperatures and/or increased pressure such that they adhere or stick to each other. Although not wishing to be limited by theory, the “interaction” or “bonding” between the two polymer films of the multi-layer polymer film can be approximated by a combination of polar and non-polar interactions, generally grouped under the term “surface energy.” Therefore, in an embodiment, the first polymer film and the second polymer film of a multi-layer polymer film are designed to have similar surface energies.
In an embodiment, the method further comprises: covering a bottom surface of the substrate with a second polymer film comprising two or more chemically resistant polymers such that the second polymer film is in contact with the bottom surface of the substrate; and heating and/or applying mechanical pressure to the second polymer film, resulting in adhesion of the second polymer film to the bottom surface of the substrate.
In an embodiment, the step of covering the bottom surface of the substrate with the second polymer film comprises extruding the second polymer film directly from compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment onto the bottom surface of the substrate. In an embodiment, the solvent-free composition described above is loaded into the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment and the second polymer is extruded from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment directly onto the bottom surface of the substrate.
In another embodiment, the step of covering the bottom surface of the substrate with the second polymer film comprises placing the second polymer film formed from the solution described above directly onto the bottom surface of the substrate.
In another embodiment, the step of covering the bottom surface of the substrate with the second polymer film comprises placing the second polymer film formed from the solvent-free composition described above directly onto the bottom surface of the substrate. In an embodiment, the step of covering the bottom surface of the substrate with the second polymer film comprises loading the solvent-free composition described above into compounding machinery, an extruder, a mixer, calendaring equipment, or milling equipment; extruding the second polymer film from the compounding machinery, the extruder, the mixer, the calendaring equipment, or the milling equipment; and placing the second polymer film directly onto the bottom surface of the substrate.
In yet another embodiment, the step of covering the bottom surface of the substrate with the second polymer film comprises depositing a solution comprising two or more chemically resistant polymers onto the bottom surface of the substrate and evaporating the solvent, forming the second polymer film. In an embodiment, the solution is described above.
In an embodiment, heating and/or applying mechanical pressure to the second polymer film in contact with the metal substrate provides increased adhesion of the second polymer film to the substrate. In an embodiment, the second polymer film adheres to the substrate and remains adhered during chemical and/or mechanical processing of the substrate. In an embodiment, the second polymer film has a first microstructure and, upon heating and/or applying mechanical pressure to the second polymer film in contact with the substrate, the second polymer film adopts a second microstructure. In an embodiment, the second microstructure has increased adhesion to the substrate.
In an embodiment, the method is preceded by the step of cleaning and/or chemically treating a top surface and/or a bottom surface of the substrate.
The first and second polymer films are described in the polymer film section elsewhere herein. The substrate is described elsewhere herein.
In an embodiment, the method further comprises the one or more of forming, scribing, mechanical, or chemical processing the masked substrate. In an embodiment, following forming scribing, mechanical and/or chemical processing, the masked substrate undergoes further treatment steps. In an embodiment, the further treatment comprises drilling and/or routing. In an embodiment, the substrate is demasked following the forming, scribing, mechanical processing, chemical processing, and/or further treatment steps.
In an embodiment, the first polymer film, the second polymer film, or both the first and second polymer films each independently have a high melt-flow such that, when it is placed in contact with a substrate under high temperature and/or high pressure, the polymer film adheres to the substrate. In an embodiment, the polymer film remains adhered to the substrate after the application of high temperature and/or high pressure is stopped. In an embodiment, the polymer film adheres to the substrate with sufficient strength that it does not fall off of the substrate if the substrate is picked up and manipulated. In an embodiment, the polymer film adheres to the substrate with sufficient strength that it does not fall off during chemical and/or mechanical processing of the substrate. In an embodiment, the substrate is a metal substrate. In an embodiment, the metal substrate is sheet metal.
In an embodiment, the first polymer film, the second polymer film, or both the first and second polymer films each independently have a first microstructure which is determined by the method used to form the film. In an embodiment, the first microstructure is not optimized to produce adhesion to the substrate. Therefore, in an embodiment, a polymer film having a first microstructure will likely fall off of the substrate when simply positioned in contact with the substrate. In an embodiment, the first polymer film, the second polymer film, or both the first and second polymer films each independently comprise low glass transition temperature polymers that have a high mobility at elevated temperatures. Therefore, in an embodiment, the step of heating and/or applying mechanical pressure to the first and/or second polymer films leads the first and/or second polymer film to form a second microstructure. In an embodiment, the (co)polymers which were used to form the first and/or second polymer film reorient under the application of heat and/or pressure, thus leading the polymer film to form a second microstructure. In an embodiment, contact with the substrate while heat and/or pressure are applied encourages mechanical and chemical interaction between the first and/or second polymer films and the substrate, thus leading the polymer film to form a second microstructure. In an embodiment, the second microstructure has increased adhesion to the substrate when compared to the first microstructure. In an embodiment, the increased adhesion of the first and/or second polymer films comprising the second microstructure is such that the polymer film(s) stay adhered to the surface of the substrate during forming, scribing, mechanical processing, and/or chemical processing. In an embodiment, the first and/or second polymer film(s) having the second microstructure act as maskant. In an embodiment, the maskant can be cut such that one or more pieces of the maskant can be removed while the majority of the maskant remains adhered to the substrate. In an embodiment, the maskant is removed after the substrate is formed, scribed, mechanically, and/or chemically processed. In an embodiment, the maskant can be removed by hand. In an embodiment, the maskant can be removed by stripping it off the surface of the substrate with a solvent. In an embodiment, the maskant can be removed by burning it off the surface of the substrate. In an embodiment, the substrate is a metal substrate.
In an embodiment wherein the first and/or second polymer film comprises two polymer films, the polymer film comprising two polymer films has a different peel adhesion than the peel adhesion of a polymer film that comprises one polymer film. In an embodiment, the peel adhesion of the first and/or second film comprising two polymer films is about 10 oz/in to about 20 oz/in before chemical processing. In an embodiment, the peel adhesion of the first and/or second film comprising two polymer films is about 15 oz/in before chemical processing. In an embodiment, the peel adhesion of the first and/or second film comprising two polymer films is about 15 oz/in to about 25 oz/in after chemical processing. In an embodiment, the peel adhesion of the first and/or second film comprising two polymer films is about 15 oz/in after chemical processing. In an embodiment, the peel adhesion of the first and/or second polymer film comprising two polymer films is measured after the first and/or second polymer film has formed the second microstructure. In an embodiment, the peel adhesion of the first and/or second polymer film comprising two polymer films is measured after the first and/or second polymer film has been subjected to high temperatures and/or high pressure to increase the adhesion of the first and/or second polymer film. In an embodiment, the peel adhesion is measured on a metal substrate. In an embodiment, the peel adhesion is measured on an aluminum substrate. In embodiment, the peel adhesion is measured on a polished clad aluminum substrate.
In an embodiment, the polymer film acts as a maskant, and when adhered to the substrate, has mechanical properties such that if a shape is delineated with tape, the maskant will tear along the tape line without significant error or rough edges. In an embodiment, the tape comprises aluminum tape. In an embodiment, the substrate is a metal substrate.
In yet another aspect, the present disclosure provides a method of chemically processing a substrate, comprising chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a substrate masked with the polymer film described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a method of chemically processing a substrate, comprising chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a substrate masked with a polymer film made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a method of chemically processing a substrate, comprising chemical milling, electroless plating, chemical surface treatment, chemical vapor deposition, or evaporative coating a masked substrate made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In yet another aspect, the present disclosure provides a method of electrochemically processing a substrate, comprising anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a substrate masked with the polymer film described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a method of electrochemically processing a substrate, comprising anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a substrate masked with a polymer film made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a method of electrochemically processing a substrate, comprising anodizing, electrochemical polishing, plating, electrostatic coating, or electrofinishing a masked substrate made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In yet another aspect, the present disclosure provides a substrate comprising an adhered maskant wherein the maskant comprises the polymer film described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a substrate comprising an adhered maskant wherein the maskant comprises a polymer film made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
In another aspect, the present disclosure provides a masked metal substrate made by the method described elsewhere herein. In an embodiment, the substrate is a metal substrate. Exemplary metal substrates are described elsewhere herein.
The following clauses describe certain embodiments of the disclosure.
Clause 1. A polymer film comprising a butadiene copolymer having a glass transition temperature of about −150° C. to about 150° C. and a butylene polymer having a glass transition temperature of about −90° C. to −40° C., wherein the butadiene copolymer and butylene polymer are oriented such that the polymer film has a first microstructure.
Clause 2. The polymer film of clause 1, wherein upon contacting the polymer film with a metal substrate under elevated temperature and/or mechanical pressure, the polymer film adopts a second microstructure.
Clause 3. The polymer film of clause 2, wherein the second microstructure has increased adhesion to the metal substrate.
Clause 4. The polymer film of any one of clauses 1-3, wherein the film is chemically resistant to acids and bases.
Clause 5. The polymer film of any one of clauses 1-4, wherein the butadiene copolymer is selected from styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), and combinations thereof.
Clause 6. The polymer film of any one of clauses 1-5, wherein the butadiene copolymer is styrene-butadiene-styrene (SBS).
Clause 7. The polymer film of clause 6, wherein SBS has a first glass transition temperature of about −115° C. to about −100° C. and a second glass transition temperature of about 95° C. to about 105° C.
Clause 8. The polymer film of any one of clauses 1-5, wherein the butadiene copolymer is a blend of styrene-ethylene-butylene-styrene (SEBS) and styrene-ethylene-propylene-styrene (SEPS).
Clause 9. The polymer film of clause 8, wherein the blend of SEBS and SEPS has a w/w ratio of about 7:1 to about 10:1.
Clause 10. The polymer film of clause 8 or 9, wherein the blend of SEBS and SEPS has a first glass transition temperature of about −50° C. to about −20° C. and a second glass transition temperature of about 90° C. to about 115° C.
Clause 11. The polymer film of any one of clauses 1-10, wherein the butylene polymer is polyisobutylene.
Clause 12. The polymer film of any one of clauses 1-11, wherein the polymer film comprises about 75% to about 95% by weight of the butadiene copolymer and about 5.0% to about 25.0% by weight of the butylene polymer.
Clause 13. The polymer film of any one of clauses 1-12, wherein the polymer film comprises about 87% by weight of the butadiene copolymer and about 13% by weight of the butylene polymer.
Clause 14. The polymer film of any one of clauses 1-13, further comprising an aromatic hydrocarbon resin, an inorganic filler, an antioxidant, or a combination thereof.
Clause 15. The polymer film of clause 14, wherein the aromatic hydrocarbon resin is a C9 resin.
Clause 16. The polymer film of clause 15, wherein the C9 resin has a softening point between about 100° C. and about 160° C.
Clause 17. The polymer film of clause 14, wherein the filler is an inorganic mineral oxide or an inorganic carbon.
Clause 18. The polymer film of clause 17, wherein the filler is selected from a silicate, talc, a feldspar, a chlorate, alumina, titania, carbon black, nanostructured carbon, and combinations thereof.
Clause 19. The polymer film of any one of clauses 14-18, wherein the polymer film comprises about 30% by weight to about 50% by weight of the butadiene polymer, about 0.5% by weight to about 15% by weight of the butylene polymer, and about 40% by weight to about 70% by weight of the combination of the aromatic hydrocarbon resin, the inorganic filler, and/or the antioxidant.
Clause 20. The polymer film of any one of clauses 1-19, wherein the polymer film is free-standing.
Clause 21. The polymer film of any one of clauses 1-20, wherein the polymer film is substantially solvent-free.
Clause 22. The polymer film of any one of clauses 1-21, wherein the tensile strength of the polymer film is about 650 psi to about 750 psi.
Clause 23. The polymer film of any one of clauses 2-22, wherein the metal substrate is sheet metal.
Clause 24. The polymer film of any one of clauses 3-23, wherein the polymer film having the second microstructure has a peel adhesion to the metal substrate of about 2 oz/in to about 35 oz/in.
Clause 25. The polymer film of clause 24, wherein the metal substrate is an aluminum substrate.
Clause 26. The polymer film of clause 25, wherein the metal substrate is polished clad aluminum.
Clause 27. A method of making a first polymer film, the method comprising:
The present disclosure relates to the use of polymeric materials with specific properties. Maskants for chemical processing must be chemically and mechanically robust, with the ability to withstand corrosive chemicals at elevated temperatures, all while protecting the substrate and remaining peelable after processing. The polymers typically used for this application are mostly non-polar and very insoluble in aqueous media. They are also mechanically tough to allow facile removal from a workpiece after chemical processing.
Typical application of a maskant to a workpiece is achieved by solution processing where the highly mobile maskant components can self-assemble onto the workpiece surface as the solubility limit is reached during evaporation (solvent-based and water-based maskants) or as the polymerization and cross-linking reaction creates an elastomeric matrix (2-component). Although not wishing to be limited by theory, structure property reasoning suggests that, if given sufficient thermal energy for rotation and translation (or mobility due to the solvation of an organic solvent) polymer chains will orient themselves to an optimized geometry/morphology with respect to a substrate's surface. This process is dependent on the chemical makeup of the polymers with glass transition temperature and melt-flow being key parameters. Supposing that the maskant has time to self-assemble during the cure/evaporation process, this is the conformation that one would expect. The creation of this adhesion is important to achieving nominal performance for maskants in chemical milling and chemical processing.
In attempting to produce maskant films on a workpiece without the use of solvated polymers or in situ polymerization reaction, the problem of material-surface self-assembly is encountered. A free-standing polymer film possesses an established microscopic structure that has been determined by the method of film formation. This microstructure is not necessarily optimized to produce adhesion to a workpiece and a randomly oriented maskant film will likely fall off of a workpiece when simply positioned in contact. The present disclosure overcomes the limitation of a preferred orientation for maskant-surface interactions by utilizing polymeric materials that can re-orient themselves to best interact with a workpiece surface. Specifically, low glass-transition temperature polymers are understood to have a high mobility at elevated temperatures. The application of elevated temperature in combination with increased pressure to encourage mechanical and chemical interaction between a maskant and a workpiece surface allows the maskant polymers to adopt the preferred orientation that will result in the maximum film adhesion, thus allowing chemical processing. This technology has the potential to significantly reduce waste, allow extremely precise coating thicknesses, and minimize the presence of air-entrapment defects.
Briefly, the present disclosure provides a masked workpiece structure formed without the use of any liquid solvents in the masking process and a method for masking a workpiece by application of a freestanding film of cured maskant. Generally, this method involves pressing the freestanding film onto the workpiece at elevated temperature and pressure for a period of time. This process results in adhesion of the maskant to the workpiece sufficient to perform the subsequent forming, scribing, and chemical processing steps required in the manufacture of aerospace parts. The structure produced includes an infinitely variable arrangement and stacking of freestanding maskant films “above” and “below” the workpiece, including maskant films of wide-ranging composition.
The present disclosure provides a method for the masking of a workpiece using the physical instruments of temperature and pressure as opposed to the chemical methods of reaction, cure, or evaporation. The present disclosure further provides a method for masking a workpiece that can be used in an industrial scale production line. The present disclosure further permits the user to mask both sides of a workpiece with at least one maskant composition. Therefore, the present disclosure allows the user to mask either side of a workpiece with multiple films of varying composition as well as with dissimilar films on either side of the workpiece.
Table 1 provides an overview of the physical property requirements of a cured maskant of the disclosure.
Table 2 provides the adhesion of a single layer polymer film to a metal substrate as the polymer film comprises increasing amounts of an inorganic filler. The amount of the inorganic filler in Table 2 refers to the concentration in a solvent based maskant that is used to solvent cast a film that can be transferred to the metal substrate once “dry.” The compositions of TM-68A to TM-68D are identical except for the variation of the ratio of the inorganic filler to the amount of SEBS and SEPS.
Table 3 provides the composition of a film that results from evaporating the solvent from the composition in Table 4 or Table 5.
Table 4 provides the ingredients for a solution that was used to make a polymer film (sample TM-68D).
Table 5 provides the ingredients for a solution that can be used to make a polymer film.
Table 6 provides chemical milling adhesion data of sample TM-68D.
Table 7 describes the mechanical properties of several maskants of the disclosure that have been cast from solvent onto aluminum substrates and then tested as freestanding films. The TM samples are softer than AC-850 HS Tan (a multi-use maskant with desired properties), but the properties can be further modified as necessary with additives. TM-68-D-1 has the same composition as TM-68D (see Table 4 and Table 5) except that it contains half the amount of polyisobutylene.
The formulations are compounded by several methods. They can be mixed in a high intensity mixer such as a Banbury mixer, for example one provided by HF Mixing Group. These mixers are frequently used to compound rubber tires prior to them being formed and vulcanized. When using the Banbury mixer, the components of the solvent-free composition described herein are all weighed and loaded into the mixing section of the Banbury mixer. The mixing section is then sealed via, typically, a hydraulic ram. The mixer is motor is engaged, turning two rotating sigma blades at high speed. A typical mix cycle is from 30 second to 3 min. At the end of the mix cycle, the fully mixed solvent-free composition is then moved from the Banbury mixer to a two-roll mill where it is calendared to a specific thickness and cooled. The cooled composition may then be cut into strips, chopped into pellets, or fed directly into a system that would act to further refine the film thickness and width.
Alternatively, the ingredients of the solvent-free composition can be fed into the hopper of a single screw or twin-screw extruder. The screw action of the extruder then feeds ingredients into a barrel section where the feed streams are mixed under heat and pressure. This has the advantage that this is a continuous process. At the end of the extruder, the mixture is typically forced through a heated die which forms a film, a rod, or even a cross section which can then be further processed for pellets, fed into a film forming apparatus, etc. The ingredients may need multiple passes through a twin-screw extruder to achieve the degree of mixing required to achieve a homogeneous mixture. A target temperature for the extruder is based on the melt-flow of the butadiene copolymer and the butylene polymer and is within the range of 160-200° C., for example 170-190° C.
Combinations of the above two methods can be used to compound the solvent-free composition. For example, a preliminary rough mixing of the components can be performed in a high intensity mixer before feeding into a twin-screw extruder that completes the mixing portion and outputs to a set of calendar rolls or a blown film apparatus.
Once the solvent-free composition is compounded, one of the following occurs: 1) a film is formed which is rolled and stored until ready to be adhered to the metal substrate, or 2) a film is formed which is then directly adhered to the metal substrate.
With respect to option 1) above, there are many methods of forming a film from a compounded thermoplastic mixture. In one method, the compounded mixture is calendared via a series of temperature controlled rolled until the desired thickness and width are obtained. The film is then typically cooled to the point it is no longer tacky and rolled up on itself. Alternatively, it can be mated with a release liner and the two rolled up together.
In another method, film blowing equipment (such as that manufactured by Kuhne Group) is used to form a film from the compounded thermoplastic mixture. This equipment has the advantage of being able to produce multi layered films of different compounds or polymers with different physical and mechanical properties. They are also known for very precise film thickness and large width. When film blowing equipment is used, the twin screw extruder is fed directly into this equipment.
With respect to option 2) above, a purpose-built piece of equipment is likely required to form the film and directly adhere it to the metal. This equipment uses a set of heated rollers to form the film from the compounded thermoplastic mixture to a thickness and film width suitable for adhering to the metal parts required. One of the last steps of this process is to place the film in contact with the metal as it progresses through the machine while controlling both the temperature of the film and the pressure used as it is placed in contact with the metal. Alternatively, the metal itself is preheated to a temperature prior to the film coming in contact with the metal.
An example demonstrating how the solvent-free composition is compounded, formed into a polymer film, and directly adhered to the metal substrate can be seen in
It is noted that terms like “preferably,” “commonly,” and “typically” are not used herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention.
The various methods and techniques described above provide a number of ways to carry out the invention. Of course, it is to be understood that not necessarily all objectives or advantages described can be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that the methods can be performed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as taught or suggested herein. A variety of alternatives are mentioned herein. It is to be understood that some preferred embodiments specifically include one, another, or several features, while others specifically exclude one, another, or several features, while still others mitigate a particular feature by inclusion of one, another, or several advantageous features.
Furthermore, the skilled artisan will recognize the applicability of various features from different embodiments. Similarly, the various elements, features and steps discussed above, as well as other known equivalents for each such element, feature or step, can be employed in various combinations by one of ordinary skill in this art to perform methods in accordance with the principles described herein. Among the various elements, features, and steps some will be specifically included, and others specifically excluded in diverse embodiments.
Although the application has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the embodiments of the invention extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and modifications and equivalents thereof.
In some embodiments, the numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used to describe and claim certain embodiments of the application are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
In some embodiments, the terms “a” and “an” and “the” and similar references used in the context of describing a particular embodiment of the application (especially in the context of certain of the following claims) can be construed to cover both the singular and the plural. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (for example, “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the application and does not pose a limitation on the scope of the application otherwise claimed. As used in the disclosure or claims, “another” means at least a second or more, unless otherwise specified. As used in the disclosure, the phrases “such as,” “for example,” and “e.g.” mean “for example, but not limited to” in that the list following the term (“such as,” “for example,” or “e.g.”) provides some examples but the list is not necessarily a fully inclusive list. The word “comprising” means that the items following the word “comprising” may include additional unrecited elements or steps; that is, “comprising” does not exclude additional unrecited steps or elements. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the application.
Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter. As used herein, the term “about,” when referring to a value or to an amount of mass, weight, time, volume, concentration or percentage is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed method.
Preferred embodiments of this application are described herein. Variations on those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. It is contemplated that skilled artisans can employ such variations as appropriate, and the application can be practiced otherwise than specifically described herein. Accordingly, many embodiments of this application include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the application unless otherwise indicated herein or otherwise clearly contradicted by context.
All patents, patent applications, publications of patent applications, and other material, such as articles, books, specifications, publications, documents, things, and/or the like, referenced herein are hereby incorporated herein by this reference in their entirety for all purposes, excepting any prosecution file history associated with same, any of same that is inconsistent with or in conflict with the present document, or any of same that may have a limiting affect as to the broadest scope of the claims now or later associated with the present document. By way of example, should there be any inconsistency or conflict between the description, definition, and/or the use of a term associated with any of the incorporated material and that associated with the present document, the description, definition, and/or the use of the term in the present document shall prevail.
In closing, it is to be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of the invention. Other modifications that can be employed can be within the scope of the application. Thus, by way of example, but not of limitation, alternative configurations of the embodiments of the application can be utilized in accordance with the teachings herein. Accordingly, embodiments of the present application are not limited to that precisely as shown and described.
The present application claims priority to U.S. patent application Ser. No. 18/493,335, filed Oct. 24, 2023, which claims priority to U.S. Provisional Application No. 63/380,618, filed Oct. 24, 2022, each of which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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63380618 | Oct 2022 | US |
Number | Date | Country | |
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Parent | 18493335 | Oct 2023 | US |
Child | 18643644 | US |