The present disclosure relates to technologies using plasma and thermal spray processes for the deposition of thin films and coatings in addition to related types of manufacturing processes. In particular, the present disclosure relates to improvement of High Velocity Oxy Fuel (HVOF) tapes used with industrial manufacturing methods including, but not limited to, plasma and thermal spray processes for alloys, ceramics, and related types of materials generally functioning to surmount the issues of excessive wear and high stress on surfaces.
Tapes for HVOF thermal processes, for example, characterized by temperatures which can exceed 600 degrees Fahrenheit and greater than 21,000 miles per hour for fuel velocity, are a longstanding need yet to be adequately addressed in aircraft, automobiles, and metal finishing industry terms.
Common among known high temperature tapes are breakdowns or related mechanical integrity challenges such as unravelings, separation from their own backings, and the like unacceptable failure modes. No known tapes including those made with high temperature carriers are effective to withstand the above noted conditions. Further, metal deposition in unwanted areas, and related contaminations are not industrially accepted and require increased cost, time, and reworking efforts.
A finished HVOF tape used, for example, during known HVOF processing imparts high temperature silicone pressure sensitive adhesives that provide enhanced adhesion strength to provide a firm adhesion to its own backing and unexpectedly leave no residue upon removal from metals. The novel enhanced HVOF tapes are made up of coated or uncoated, woven or non-woven glass cloth and ceramic based fabric laminated to at least one side of a metal foil using a silicone based laminating adhesive, which is then laminated with another layer of a pre-selected combination of the same materials and coated with a high temperature silicone pressure sensitive adhesive and wound to itself to make a self wound HVOF tape or covered adhesive assembly with a release liner to make a laminated sheet for die cut samples, among other things. Applications including military and commercial aircraft, automobiles, and metal finishing usages leverage off of the unique and inherent benefits of the novel enhanced HVOF tapes of the instant teachings.
According to features of the present disclosure, there is provided a multilayered laminated HVOF tape comprising, in combination a plurality of layers including having at least: a first layer; a third layer, further comprising any one of the group consisting of: aluminum foil, steel foil, copper foil, wool paper, polyamide paper, and polyamide woven fabric; a first adhesive layer; a glass cloth layer, wherein the glass cloth layer is a glass or ceramic fiber that is either woven or felt; a second adhesive layer; wherein the resulting HVOF tape which provides for high strength and non-flammable resistance to high temperature, high velocity, and high pressure when used during an HVOF process.
According to features of the present disclosure, there is provided a multilayered laminated HVOF tape comprising, in combination: a plurality of layers including having at least: a glass cloth layer; a first layer; a third layer, further comprising any one of the group consisting of: aluminum foil, steel foil, copper foil, wool paper, polyamide paper, and polyamide woven fabric; a second adhesive layer; wherein the resulting HVOF tape which provides for high strength and non-flammable resistance to high temperature, high velocity, and high pressure when used during an HVOF process.
According to features of the present disclosure, there is provided a multilayered laminated HVOF tape comprising, in combination: a first release liner; a first high temperature silicone pressure sensitive adhesive; one of a first high temperature fabric and a high temperature silicone foam; a first laminating adhesive; one of a metal foil and a silicone foam; a second laminating adhesive; a second high temperature fabric; a second high temperature silicone pressure sensitive adhesive; and a second release liner.
The above-mentioned features and objects of the present disclosure will become more apparent with reference to the following description taken in conjunction with the accompanying drawings wherein like reference numerals denote like elements and in which:
The present inventor has discovered that laminated materials preventing the types of failures detailed above can be simply and elegantly generated to address the longstanding needs existing among the prior art. The laminates of the instant teachings include more than one layer of coated or uncoated glass cloth laminated with a metal foil with high temperature inorganic silicone based adhesives—both pigmented and unpigmented.
What is unexpectedly better than dictated by empirical data are the excellent conformability and sealing properties, including the self-attachment achieved with the instant laminates. An ability to withstand extreme high temperatures and high fuel velocity up to a magnitude of at least about 21,000 miles per hour is likewise believed to differentiate the instant teachings from known art in novelty terms, as discussed herein, illustrated by the schematic and exemplary versions of the embodiments presented as figures and defined by the claimed appended. According to embodiments of the teachings of the present disclosure, there is disclosed a silicone pressure sensitive adhesive which, used according to the instant processes retained physical properties like adhesion to surfaces and to its own backing after being exposed to extreme conditions in testing.
The composition of silicone pressure sensitive adhesives (PSA) is similar to many common organic PSAs. However, silicone PSAs are appropriate in high temperature applications in which organic PSAs fail. The characteristics that dictate the performance of silicone PSAs are high molecular weight linear siloxane polymers and a highly condensed silicate tackifying resin, such as MQ resin. An example of a typical silicone polymer used in the present disclosure is:
Typical commercially available silicone PSAs are polydimethylsiloxane (PDMS) polymer, polydiphenylsiloxane (PDPS) polymer, and polydimethyldiphenylsiloxane (PDMDPS) polymer, which have silanol or vinyl functional groups at the polymer chain ends.
MQ is a silicate resin commercially available as a solid suspended in a hydrocarbon solvent and is disclosed in U.S. Pat. No. 5,330,747, which is hereby expressly incorporated by reference as if fully set forth herein. It comprises a core of SiO4/2 “Q” units, which are surrounded by a shell of Me3SiO “M” units. MQ units undergo a condensation reaction with a siloxane polymer due to silanol functional groups in the shell, forming a covalent bond between the MQ resin and the siloxane polymer. The ratio of resin to polymer must optimized for each application, but can done without undue experiments by a person of ordinary skill in the art.
Adhesion of PSAs in a pressure sensitive manner occurs by removing solvents. To increase and reinforce the adhesion network, the PSAs may be cured. PSA curing systems are commercially available. One system is a peroxide-catalyzed free-radical cure system. It uses either benzoyl peroxide or 2,4-dichlorobenzoyl peroxide. The details of these systems are well known in the art. Another common system contemplated by the present disclosure for curing PSAs is a platinum-based system, which is also commercially available and well-known in the art. The advantage of platinum-based systems are the lack byproducts and the ability to cure while evaporating the solvent at low temperature.
The present disclosure is a process for making a multilayered laminated HVOF tape which comprises, attaching a plurality of layers of glass cloth laminated with metal foils, aramid paper, or ceramic papers with high temperature inorganic silicone based adhesives, and finishing a resulting HVOF tape which provides for high strength and non-flammable resistance to high temperature, high velocity, and high pressure when used during an HVOF process. Using this process, it is further understood that in certain instances of the process above, the attaching step further includes a first silicone rubber coating, followed by a woven or non-woven high temperature fabric, a laminating adhesive, a metal foil, another layer of laminating adhesive, and a woven or non-woven high temperature fabric, a silicone pressure sensitive adhesive and an optional release liner. Similarly, the product, produced by the process of described above works whereby the plurality of layers in the attaching step further includes a first silicone rubber coating, followed by a laminating adhesive, a metal foil, another layer of laminating adhesive, a woven or non-woven high temperature fabric, a silicone pressure sensitive adhesive, and an optional release liner.
The present disclosure likewise contemplates that in a product, produced by the above process, the plurality of layers in the attaching step further includes a first silicone rubber coating, followed by a woven or non-woven high temperature fabric; a laminating adhesive; a metal foil, ceramic paper, polyamide paper; a silicone pressure sensitive adhesive; and an optional release liner.
In another and alternative construction, a laminated assembly is disclosed wherein there is a laminated HVOF tape comprised of at least coated and uncoated glass cloth and ceramic based fabric laminated to one or both sides of at least one foil selected from the group consisting of copper, steel, aluminum, and other metal foils with a silicone laminating adhesive, which is then again laminated with another layer of woven or nonwoven glass cloth or ceramic based fabric which is coated with a high temperature silicone pressure sensitive adhesive and wound to itself to make a self wound HVOF tape.
Yet still another embodiment according to the present disclosure is shown, wherein the laminated HVOF tape product is comprised of at least one of coated and uncoated glass cloth and ceramic based fabric laminated to one or both sides of at least one foil selected from the group consisting of copper, steel, aluminum, and other metal foils with a silicone laminating adhesive which is then again laminated with another layer of woven or non woven glass cloth or ceramic based fabric which is coated with a high temperature silicone pressure sensitive adhesive and wound to itself to make a laminated sheet, or to make an assembly from which die cut samples may be made.
First layer 102 is a pressure sensitive layer made from a polydimethylsiloxane (PDMS) polymer, polydiphenylsiloxane (PDPS) polymer, or a polydimethyldiphenylsiloxane (PDMDPS) polymer. In an embodiment, MQ resin may optionally be added as a tackifying agent. Moreover, a release liner (not shown) is optional in the configuration where first layer 102 is a pressure sensitive adhesive.
Optionally, first layer 102 may be a pressure insensitive (pressure insensitive defined to be not pressure sensitive) silastic coating, which is a non-tacky silicone rubber or elastomer coating. Additionally, first layer 102 may be a PDMS, PDPS, or PDMDPS polymer having a nonorganic fire resistant filler. Nonorganic fire resistant fillers may be ceramic powder, metal, glass, metal oxides, or combinations of ceramic powder, metal, glass, or metal oxide fillers. Examples of fire resistant fillers contemplated by the present disclosure are ferro oxide, titanium oxide, boron nitride, zirconium oxide, sodium silicate, and magnesium silicate, although others are suitable as well.
First layer 102 may also be a nonthermally conductive material, in embodiments. An example of a nonthermally conductive material is zirconium woven cloth or felt. Zirconium is defined to be a material comprising 50% to 100% ZrO2. A more effective embodiment comprises 70% to 100% ZrO2.
In another embodiment, the nonthermally conductive material is a siloxane-based foam that is either pressure sensitive or pressure insensitive, comprising the siloxane-based foam with a density of about 0.01 to about 1.00 g/cm3. The foam may optionally include at least one non-flammable filler, which may be ceramic powder, metal, glass, metal oxides, or combinations of ceramic powder, metal, glass, or metal oxide fillers. Examples of fire resistant fillers contemplated by the present disclosure are ferro oxide, titanium oxide, boron nitride, zirconium oxide, sodium silicate, and magnesium silicate, although others are suitable as well.
Second layer 104 is an optional laminating layer depending on how well first layer 102 adheres to third layer 106. However, when included, second layer comprises an adhesive bonding first layer to third layer, such as a PDMS, PDPS, PDMDPS-based pressure sensitive adhesive or a PDMS, PDPS, PDMDPS-based adhesive that is pressure insensitive at room temperature.
Third layer 106 is also an optional layer comprising a metal film or foil. The present disclosure contemplates using an aluminum foil, steel foil, copper foil, or other types of metal foil. In other embodiments, metal foil is substituted with wool paper, polyamide paper, carbon paper, ceramic paper, or polyamide felt. The layer should be about 0.1 mm to about 5.00 mm thick. In a particularly effective embodiment, copper foil of thickness of about 0.025 mm to about 0.13 mm is used.
First adhesive 108 is a PDMS, PDPS, or PDMDPS polymer based adhesive. It must be able to adhere to whatever components form first layer 102, second layer 104, or third layer 106 and glass cloth 110. First adhesive 108 works well as both a pressure sensitive adhesive or a pressure insensitive adhesive. The adhesive may optionally include at least one non-flammable additive, which may be ceramic powder, metal, glass, metal oxides, or combinations of ceramic powder, metal, glass, or metal oxide additives. Examples of fire resistant additives contemplated by the present disclosure are ferro oxide, titanium oxide, boron nitride, zirconium oxide, sodium silicate, and magnesium silicate, although others are suitable as well.
Glass cloth 110 is a woven or felt cloth made of glass fiber, silicate fiber, ceramic fiber, aramid fiber, polyamide fiber, or carbon fiber.
Like first adhesive 108, second adhesive 112 is a PDMS, PDPS, or PDMDPS polymer based adhesive. It may either be a pressure sensitive adhesive or a pressure insensitive adhesive. A particularly effective embodiment is a pressure sensitive adhesive uses a PDPS polymer based adhesive. The adhesive may optionally include at least one non-flammable additive, which may be ceramic powder, metal, glass, metal oxides, or combinations of ceramic powder, metal, glass, or metal oxide additives. Examples of fire resistant additives contemplated by the present disclosure are ferro oxide, titanium oxide, boron nitride, zirconium oxide, sodium silicate, and magnesium silicate, although others are suitable as well.
Finally, release liner 114 may take a number of forms in embodiments. For example, it may be a thin layer web that covers second adhesive 112. Alternately, it may be corrugated or embossed film, such as polyolefin or PVC. It may also be a smooth plastic film or paper coated with a flourosilicone coated release layer that does not bond to second adhesive 112. Release liner 114 should be able to be easily and manually removed from second adhesive 112 without changing the physical or functional properties of second adhesive 112. Other release liners having similar properties are similarly contemplated as would be known to those skilled in the art.
Because glass layer is the topmost layer, first layer 102 is modified to be a pressure sensitive adhesive layer made from PDMS polymer, PDPS polymer, or PDMDPS polymer serving as an adhesive binding glass cloth 110 to the other layers. In an embodiment, MQ resin may optionally be added to first layer 102 as a tackifying agent. Optionally, first layer may be a PDMS, PDPS, or PDMDPS polymer having a nonorganic fire resistant additive. Nonorganic fire resistant additives may be ceramic powder, metal, glass, metal oxides, or combinations of ceramic powder, metal, glass, or metal oxide additives. Examples of fire resistant additives contemplated by the present disclosure are ferro oxide, titanium oxide, boron nitride, zirconium oxide, sodium silicate, and magnesium silicate, although others are suitable as well. First layer 102 may also be a pressure insensitive silastic coating, which is a non-tacky silicone rubber or elastomer coating.
A fourth embodiment exemplified by
The present inventor has disclosed that the material characteristics necessary to transform conventional tapes into HVOF tape, which provides interesting and useful results when optimized. Unexpectedly improved products have consequently been developed using the results set forth in the following tables in the process of optimizing the instant teachings.
Table 1 shows exemplary embodiments and their respective strengths with respect to key parameters of the instant disclosure. Table 2 demonstrates variations in the formulation of silicone adhesive and silastic silicone rubber layers reviewed in completion of the teachings of the instant disclosure. Units of the layers are in parts per total weight (e.g. the total weight of HVOF tape example 1043 is 105 parts, wherein 100 parts are PDMP Silicone PSA and 5 parts benzoyl peroxide).
While the apparatus and method have been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the disclosure need not be limited to the disclosed embodiments. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures. The present disclosure includes any and all embodiments of the following claims.
This application is related to and claims the priority of U.S. Provisional Application No. 60/652,693 filed on Feb. 14, 2005, which is hereby expressly incorporated by reference in its entirety.
Number | Date | Country | |
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60652693 | Feb 2005 | US |