Patent Application
20050279029
In general, coated abrasive articles have abrasive particles secured to a backing. More typically, coated abrasive articles comprise a backing having two major opposed surfaces and an abrasive layer secured to one of the major surfaces. The abrasive layer is typically comprised of abrasive particles and a binder, wherein the binder serves to secure the abrasive particles to the backing.
One common type of coated abrasive article has an abrasive layer which comprises a make layer, a size layer, and abrasive particles. In making such a coated abrasive article, a make layer comprising a first binder precursor is applied to a major surface of the backing. Abrasive particles are then at least partially embedded into the make layer (e.g., by electrostatic coating), and the first binder precursor is cured (i.e., crosslinked) to secure the particles to the make layer. A size layer comprising a second binder precursor is then applied over the make layer and abrasive particles, followed by curing of the binder precursors.
Another common type of coated abrasive article comprises an abrasive layer secured to a major surface of a backing, wherein the abrasive layer is provided by applying a slurry comprised of binder precursor and abrasive particles onto a major surface of a backing, and then curing the binder precursor.
In another aspect, coated abrasive articles may further comprise a supersize layer covering the abrasive layer. The supersize layer typically includes grinding aids and/or anti-loading materials.
Optionally, backings used in coated abrasive articles may be treated with one or more applied coatings. Examples of typical backing treatments are a backsize layer (i.e., a coating on the major surface of the backing opposite the abrasive layer), a presize layer or a tie layer (i.e., a coating on the backing disposed between the abrasive layer and the backing), and/or a saturant that saturates the backing. A subsize is similar to a saturant, except that it is applied to a previously treated backing.
However, depending on the particular choice of abrasive layer and backing (treated or untreated), the abrasive layer may partially separate from the backing during abrading resulting in the release of abrasive particles. This phenomenon is known in the abrasive art as “shelling”. In most cases, shelling is undesirable because it results in a loss of performance.
In one approach, a tie layer disposed between the backing and the abrasive layer has been used to address the problem of shelling in some coated abrasive articles.
Yet, despite such advances, there remains a continuing need for new materials and methods that can reduce the problem of shelling in coated abrasive articles.
In one aspect, the present invention provides a method of making a coated abrasive article comprising:
In another aspect, the present invention provides a method of making a coated abrasive article comprising:
In yet another aspect, the present invention provides a coated abrasive article comprising:
Coated abrasive articles according to the present invention are typically useful for abrading a workpiece, and may exhibit low levels of controlling shelling during abrading processes.
As used herein, the term “(meth)acryl” includes both “acryl” and “methacryl”.
Coated abrasive articles according to present invention comprise a backing having a major surface, a composite tie layer secured to at least a portion of the major surface, and an abrasive layer secured to at least a portion of the composite tie layer.
Suitable backings include those known in the art for making coated abrasive articles. Typically, the backing has two opposed major surfaces. The thickness of the backing generally ranges from about 0.02 to about 5 millimeters, desirably from about 0.05 to about 2.5 millimeters, and more desirably from about 0.1 to about 0.4 millimeter, although thicknesses outside of these ranges may also be useful.
The backing may be flexible or rigid, and may be made of any number of various materials including those conventionally used as backings in the manufacture of coated abrasives. Examples include paper, cloth, film, polymeric foam, vulcanized fiber, woven and nonwoven materials, combinations of two or more of these materials. The backing may also be a laminate of two materials (e.g., paper/film, cloth/paper, film/cloth).
Exemplary flexible backings include polymeric film (including primed films) such as polyolefin film (e.g., polypropylene including biaxially oriented polypropylene, polyester film, polyamide film, cellulose ester film), metal foil, mesh, scrim, foam (e.g., natural sponge material or polyurethane foam), cloth (e.g., cloth made from fibers or yarns comprising polyester, nylon, silk, cotton, and/or rayon), paper, vulcanized paper, vulcanized fiber, nonwoven materials, and combinations thereof. Cloth backings may be woven or stitch bonded.
The backing may be a fibrous reinforced thermoplastic such as described, for example, as described, for example, in U.S. Pat. No. 5,417,726 (Stout et al.), or an endless spliceless belt, for example, as described, for example, in U.S. Pat. No. 5,573,619 (Benedict et al.), the disclosures of which are incorporated herein by reference. Likewise, the backing may be a polymeric substrate having hooking stems projecting therefrom such as that described, for example, in U.S. Pat. No. 5,505,747 (Chesley et al.), the disclosure of which is incorporated herein by reference. Similarly, the backing may be a loop fabric such as that described, for example, in U.S. Pat. No. 5,565,011 (Follett et al.), the disclosure of which is incorporated herein by reference.
Exemplary rigid backings include metal plates, and ceramic plates. Another example of a suitable rigid backing is described, for example, in U.S. Pat. No. 5,417,726 (Stout et al.), the disclosure of which is incorporated herein by reference.
The backing may be a treated backing having one or more treatments applied thereto such as, for example, a presize, a backsize, a subsize, and/or a saturant. Additional details regarding backing treatments can be found in, for example, U.S. Pat. No. 5,108,463 (Buchanan et al.); U.S. Pat. No. 5,137,542 (Buchanan et al.); U.S. Pat. No. 5,328,716 (Buchanan); and U.S. Pat. No. 5,560,753 (Buchanan et al.), the disclosures of which are incorporated herein by reference.
The composite tie layer is typically prepared by at least partially polymerizing a composite tie layer precursor. The composite tie layer precursor is typically prepared according to a two-step process.
In a first step, a first polymerizable composition is applied to at least a portion a backing. The first polymerizable composition is isotropic and comprises at least one polyfunctional aziridine. The first polymerizable composition may further comprise surfactant (e.g., cationic, anionic and/or nonionic surfactant) to aid in wetting the backing Typically, the first polymerizable composition includes water and/or organic solvent (e.g., methyl ethyl ketone, glyme, propanol) to reduce the viscosity and/or solids content of the first polymerizable composition to a level that is suitable for the chosen method of application (e.g., knife coating, roll coating, gravure coating, or spray coating), although this is not a requirement. If present, the water or other solvent is then typically at least partially removed (e.g., by evaporation) prior to the second step, although this is not a requirement. Optionally, a period of at least 10, 20, or 30 seconds or even longer, may elapse prior to commencing the second step.
The first polymerizable composition is typically coated on the backing so as to achieve a dried add on weight in a range of from about 0.1 grams/meter2 (gsm) up to 10 gsm, although higher and lower dry add on weights may also be used.
In a second step, a second polymerizable composition is applied to at least a portion of the coated (and optionally dried) first polymerizable composition. The second polymerizable composition comprises at least one acidic free-radically polymerizable monomer and at least one oligomer having at least two pendant free-radically polymerizable groups, wherein homopolymerization of the oligomer results in a polymer having a glass transition temperature of less than 50 degrees Celsius. The second polymerizable composition may include water or other solvent and/or at least one reactive diluent to reduced the viscosity and/or solids content of the first polymerizable composition to a level that is suitable for the chosen method of application (e.g., knife coating, roll coating, gravure coating, or spray coating), although this is not a requirement. The second polymerizable composition may, optionally, further comprise a curative that is capable of inducing free-radical polymerization. If present, the water or other solvent is then typically at least partially removed (e.g., by evaporation) prior to the second step to form a composite tie layer precursor, although this is not a requirement. After an optional period of at least about 30 seconds, the composite tie layer precursor is at least partially polymerized.
The second polymerizable composition is typically coated on the at least partially dried coated first polymerizable composition so as to achieve a dried add on weight in a range of from about 0.1 grams/meter2 (gsm) up to 400 gsm, more typically about 110 gsm, although higher and lower dry add on weights may also be used.
Some intermixing of the polyfunctional aziridine, acidic free-radically polymerizable monomer, and oligomer having at least two pendant free-radically polymerizable groups may occur during the two-step process leading to a two layer composite tie layer, or a one-layer composite tie layer having a concentration gradient (e.g. of polyfunctional aziridine) across its thickness, but the process is typically not be carried out such that the polyfunctional aziridine, acidic free-radically polymerizable monomer and oligomer having at least two pendant free-radically polymerizable groups intermix to form an isotropic tie layer precursor. Thus, the term “composite tie-layer” is intended to draw attention to the two-step nature of the composite tie layer manufacture rather than to imply that the composite tie layer includes two discreet layers.
Typically, composite tie layer weight is in a range of from about 0.1 gsm up to about 400 gsm, more typically, typically about 110 gsm, although higher and lower weights may also be used.
As used herein, the term “polyfunctional aziridine” refers to a species having a plurality of aziridinyl groups. Suitable polyfunctional aziridines include, for example, those disclosed in U.S. Pat. No. 3,225,013 (Fram); U.S. Pat. No. 4,769,617 (Canty); and U.S. Pat. No. 5,534,391 (Wang), the disclosures of which are incorporated herein by reference. Specific examples include trimethylolpropane tris[3-aziridinyl propionate]; trimethylolpropane tris[3-(2-methylaziridinyl)propionate]; trimethylolpropane tris[2-aziridinylbutyrate]; tris(1-aziridinyl)phosphine oxide; tris(2-methyl-1-aziridinyl)phosphine oxide; pentaerythritol tris[3-(1-aziridinyl)propionate]; and pentaerythritol tetrakis[3-(1-aziridinyl)propionate]. Combinations of more than one polyfunctional aziridine may also be used.
Commercially available polyfunctional aziridines include those available under the trade designations “XAMA-2” (believed to be trimethylolpropane tris[3-(2-methylaziridinyl)propanoate]) and “XAMA-7” (believed to be pentaerythritol tris(beta-(N-aziridinyl)propionate)) from EIT, Inc. Corporation, Lake Wylie, S.C.; “HYDROFLEX XR2990” (believed to be trimethylolpropane tris[3-(2-methylaziridinyl)propanoate]) from H.B. Fuller Co., Vadnais Heights, Minn.; and “NEOCRYL CX-100” (believed to be trimethylolpropane tris[3-(2-methylaziridinyl)-propanoate]) from Zeneca Resins, Wilmington, Mass.
The amount of polyfunctional aziridine incorporated into the composite tie layer precursor is generally in a range of from at least 0.1, 0.5, 1, or 2 percent by weight up to and including 4, 6, 8, or even 10 percent by weight, or more, based on the total weight of polyfunctional aziridine, acidic free-radically polymerizable monomer, and oligomer having at least two pendant free-radically polymerizable groups.
The acidic free-radically polymerizable monomer has both an acidic group and a group (e.g., a (meth)acryl group) that is free-radically polymerizable. The acidic group may be, for example, carbon-, sulfur-, or phosphorus-based, and may be the free acid or in a partially or fully neutralized state. The acidic free-radically polymerizable monomer may have more than one acidic groups and/or free-radically polymerizable groups.
Useful carbon-based acidic free-radically polymerizable monomers include, for example, (meth)acrylic acid, maleic acid, monoalkyl esters of maleic acid, fumaric acid, monoalkyl esters of fumaric acid, itaconic acid, isocrotonic acid, crotonic acid, citraconic acid, and beta-carboxyethyl acrylate.
Useful sulfur-based acidic free-radically polymerizable monomers include, for example, 2-sulfoethyl methacrylate, styrene sulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid.
Useful phosphorus-based acidic free-radically polymerizable monomers include, for example, vinyl phosphonic acid.
Acidic, free-radically polymerizable monomers are commercially available, for example, under the trade designations “PHOTOMER 4173” from Cognis Corp., Cincinnati, Ohio, and “CN118”, “CD9050”, “CD9051” and “CD9052” all from Sartomer Co., Exton Pa.
The amount of acidic free-radically polymerizable monomer incorporated into the composite tie layer precursor is generally in a range of from at least 1, or 2 percent by weight up to and including 5, 10, 20, 30, or even 45 percent by weight, or more, based on the total weight of polyfunctional aziridine, acidic free-radically polymerizable monomer, and oligomer having at least two pendant free-radically polymerizable groups.
The oligomer having at least two pendant free-radically polymerizable groups is selected such that free-radical homopolymerization of the oligomer (e.g., by photo- or thermal initiation) results in a polymer having a glass transition temperature at or below 50 degrees Celsius (° C.). As used herein, the term “oligomer” refers to molecule composed of a small number of linked monomer units. Oligomers generally have less than one hundred monomer units and more typically less than thirty.
Useful oligomers having at least two pendant free-radically polymerizable groups include, for example, aliphatic and aromatic urethane (meth)acrylate oligomers, polybutadiene (meth)acrylate oligomer, acrylic (meth)acrylate oligomers, polyether (meth)acrylate oligomers, aliphatic and aromatic polyester (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, and combinations thereof.
Methods for making such oligomers are well known in the art, and many useful free-radically polymerizable oligomers are commercially available. Examples include aliphatic and aromatic urethane (meth)acrylate oligomers such as those available from UCB Chemicals Corp., Smyrna, Ga., under the trade designations “EBECRYL 270”, “EBECRYL 8804”, “EBECRYL 8807”, “EBECRYL 4827”, “EBECRYL 6700”, “EBECRYL 5129”, or “EBECRYL 8402” and those available from Sartomer Co., Exton, Pa., under the trade designations “CN 1963”, “CN 934”, “CN 953B70”, “CN 984”, “CN 962”, “CN 964”, “CN 965”, “CN 972”, “CN 978”; polyester (meth)acrylate oligomers such as those available from UCB Chemicals Corp. under the trade designations “EBECRYL 80”, “EBECRYL 81”, “EBECRYL 657”, “EBECRYL 810”, “EBECRYL 450”, “EBECRYL 870”, or “EBECRYL 2870” and that available from Sartomer Co. under the trade designation “CN 292”; polyether (meth)acrylate oligomers such as those available from Sartomer Co. under the trade designations “CN 501”, “CN 502”, “CN 550”, “CN 551”; acrylic oligomers such as those available from Sartomer Co. under the trade designations “CN 816”, “CN 817”, “CN 818”; epoxy (meth)acrylate oligomers such as that available from Sartomer Co. under the trade designation “CN119”, and “CN121”; and polybutadiene (meth)acrylate oligomers such as that available from Sartomer Co. under the trade designation “CN 301”.
The amount of oligomer incorporated into the composite tie layer precursor is generally in a range of from at least 30, 35, 40, or 45 percent by weight up to and including 50, 60, 70, 80, 90, or even 95 percent by weight, or more, based on the total weight of polyfunctional aziridine, acidic free-radically polymerizable monomer, and oligomer having at least two pendant free-radically polymerizable groups. The composite tie layer precursor may, optionally, further comprise one or more curatives that are capable of at least partially polymerizing the composite tie layer precursor. Useful curatives include free-radical initiators such as, for example, photoinitiators and/or thermal initiators for free-radical polymerization. Blends of photo-and/or thermal initiators may be used.
Useful photoinitiators include those known as useful for photocuring free-radically polyfunctional acrylates. Exemplary photoinitiators include benzoin and its derivatives such as alpha-methylbenzoin; alpha-phenylbenzoin; alpha-allylbenzoin; alpha-benzylbenzoin; benzoin ethers such as benzil dimethyl ketal (e.g., as commercially available under the trade designation “IRGACURE 651” from Ciba Specialty Chemicals, Tarrytown, N.Y.), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its derivatives such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (e.g., as commercially available under the trade designation “DAROCUR 1173” from Ciba Specialty Chemicals) and 1-hydroxycyclohexyl phenyl ketone (e.g., as commercially available under the trade designation “IRGACURE 184” from Ciba Specialty Chemicals); 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (e.g., as commercially available under the trade designation “IRGACURE 907” from Ciba Specialty Chemicals); 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (e.g., as commercially available under the trade designation “IRGACURE 369” from Ciba Specialty Chemicals).
Other useful photoinitiators include, for example, pivaloin ethyl ether, anisoin ethyl ether, anthraquinones (e.g., anthraquinone, 2-ethylanthraquinone, 1-chloroanthraquinone, 1,4-dimethylanthraquinone, 1-methoxyanthraquinone, or benzanthraquinone), halomethyltriazines, benzophenone and its derivatives, iodonium salts and sulfonium salts, titanium complexes such as bis(eta5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium (e.g., as commercially available under the trade designation “CGI 784DC” from Ciba Specialty Chemicals); halomethyl-nitrobenzenes (e.g., 4-bromomethylnitrobenzene), mono- and bis-acylphosphines (e.g., as commercially available from Ciba Specialty Chemicals under the trade designations “IRGACURE 1700”, “IRGACURE 1800”, “IRGACURE 1850”, and “DAROCUR 4265”).
One or more spectral sensitizers (e.g., dyes) may be added to the composite tie layer precursor in combination with the optional photoinitiator, for example, in order to increase sensitivity of the photoinitiator to a specific source of actinic radiation.
Examples of suitable thermal free-radical polymerization initiators include peroxides such as benzoyl peroxide, dibenzoyl peroxide, dilauryl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide; hydroperoxides such as tert-butyl hydroperoxide and cumene hydroperoxide; dicyclohexyl peroxydicarbonate; 2,2′-azobis(isobutyronitrile); and t-butyl perbenzoate. Examples of commercially available thermal free-radical polymerization initiators include initiators available from E.I. du Pont de Nemours and Co., Wilmington, Del., under the trade designation “VAZO” (e.g., “VAZO 64” and “VAZO 52”) and from Elf Atochem North America, Philadelphia, Pa., under the trade designation “LUCIDOL 70”.
If present, the curative is typically used in an amount effective to facilitate polymerization, for example, in an amount in a range of from about 0.01 percent by weight up to about 10 percent by weight, based on the total amount of tie layer precursor, although amounts outside of these ranges may also be useful.
In addition to other components, the composite tie layer precursor of the present invention may contain optional additives, for example, to modify performance and/or appearance. Exemplary additives include, fillers, solvents, plasticizers, wetting agents, surfactants, pigments, coupling agents, fragrances, fibers, lubricants, thixotropic materials, antistatic agents, suspending agents, pigments, and dyes.
Reactive diluents may also be added to the composite tie layer precursor, for example, to adjust viscosity and/or physical properties of the cured composition. Examples of suitable reactive diluents include diluents mono and polyfunctional (meth)acrylate monomers (e.g., ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tripropylene glycol di(meth)acrylate), vinyl ethers (e.g., butyl vinyl ether), vinyl esters (e.g., vinyl acetate), and styrenic monomers (e.g., styrene).
The application of the tie layer precursor to the backing can be performed in a variety of ways including, for example, such techniques as brushing, spraying, roll coating, curtain coating, gravure coating, and knife coating. Organic solvent may be added to the isotropic polymerizable composition to facilitate the specific coating technique used. The coated backing may then be processed for a time at a temperature sufficient to dry (if organic solvent is present) and at least partially polymerize the coating thereby securing it to the backing.
After an optional period of at least about 30 seconds, the tie layer precursor is typically at least partially polymerized, for example, by any of a number of well-known techniques such as, for example, by exposure electron beam radiation, actinic radiation (i.e., ultraviolet and/or visible electromagnetic radiation), and thermal energy. If actinic radiation is used, at least one photoinitiator is typically present in the tie layer precursor. If thermal energy is used, at least one thermal initiator is typically present in the tie layer precursor. The polymerization may be carried out in air or in an inert atmosphere such as, for example, nitrogen or argon.
In one exemplary embodiment, abrasive layer comprises a make layer comprising a first binder resin, abrasive particles embedded in the make layer, and a size layer comprising a second binder resin secured to the make layer and abrasive particles.
Referring to
The make and size layers may comprise any binder resin that is suitable for use in abrading applications. Typically, the make layer is prepared by coating at least a portion of the backing (treated or untreated) with a make layer precursor. Abrasive particles are then at least partially embedded (e.g., by electrostatic coating) in the make layer precursor comprising a first binder precursor, and the make layer precursor is at least partially polymerized. Next, the size layer is prepared by coating at least a portion of the make layer and abrasive particles with a size layer precursor comprising a second binder precursor (which may be the same as, or different from, the first binder precursor), and at least partially curing the size layer precursor. In one embodiment, the make layer precursor may be partially polymerized prior to coating with abrasive particles and further polymerized at a later point in the manufacturing process.
In one embodiment, a supersize may be applied to at least a portion of the size layer. Useful first and second binder precursors are well known in the abrasive art and include, for example, free-radically polymerizable monomer and/or oligomer, epoxy resins, phenolic resins, melamine-formaldehyde resins, aminoplast resins, cyanate resins, or combinations thereof.
Useful abrasive particles are well known in the abrasive art and include for example, fused aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, tungsten carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina zirconia, sol gel abrasive particles, silica, iron oxide, chromia, ceria, zirconia, titania, silicates, metal carbonates (such as calcium carbonate (e.g., chalk, calcite, marl, travertine, marble and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (e.g., quartz, glass beads, glass bubbles and glass fibers) silicates (e.g., talc, clays, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate) metal sulfates (e.g., calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate), gypsum, aluminum trihydrate, graphite, metal oxides (e.g., tin oxide, calcium oxide), aluminum oxide, titanium dioxide) and metal sulfites (e.g., calcium sulfite), metal particles (e.g., tin, lead, copper), plastic abrasive particles formed from a thermoplastic material (e.g., polycarbonate, polyetherimide, polyester, polyethylene, polysulfone, polystyrene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polymers, polyvinyl chloride, polyurethanes, nylon), plastic abrasive particles formed from crosslinked polymers (e.g., phenolic resins, aminoplast resins, urethane resins, epoxy resins, melamine-formaldehyde, acrylate resins, acrylated isocyanurate resins, urea-formaldehyde resins, isocyanurate resins, acrylated urethane resins, acrylated epoxy resins), and combinations thereof.
In another exemplary embodiment of a coated abrasive article according to the present invention, the abrasive layer may comprise abrasive particles dispersed in a binder. Referring now to
In making such a coated abrasive article, a slurry comprising a binder precursor and abrasive particles is typically applied to a major surface of the backing, and the binder precursor is then at least partially cured. Suitable binder precursors and abrasive particles include, for example, those listed hereinabove.
In another exemplary embodiment, a coated abrasive article according to the present invention may comprise a structured abrasive article. Referring now to
In making such a coated abrasive article, a slurry comprising a binder precursor and abrasive particles may be applied to a tool having a plurality of precisely-shaped cavities therein. The slurry is then at least partially polymerized and adhered to the composite tie layer, for example, by adhesive or addition polymerization of the slurry. Suitable binder precursors and abrasive particles include, for example, those listed hereinabove.
The abrasive composites may have a variety of shapes including, for example, those shapes selected from the group consisting of cubic, block-like, cylindrical, prismatic, pyramidal, truncated pyramidal, conical, truncated conical, cross-shaped, and hemispherical.
Optionally, coated abrasive articles may further comprise, for example, a backsize (i.e., a coating on the major surface of the backing opposite the major surface having the abrasive coat), a presize and/or subsize (i.e., a coating between the composite tie layer and the major surface to which the composite tie layer is secured), and/or a saturant which coats both major surfaces of the backing. Coated abrasive articles may further comprise a supersize covering at least a portion of the abrasive coat. If present, the supersize typically includes grinding aids and/or anti-loading materials.
Coated abrasive articles according to the present invention may be converted, for example, into belts, rolls, discs (including perforated discs), and/or sheets. For belt applications, two free ends of the abrasive sheet may be joined together using known methods to form a spliced belt.
Further description of techniques and materials for making coated abrasive articles may be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,518,397 (Leitheiser et al.); U.S. Pat. No. 4,588,419 (Caul et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,652,275 (Bloecher et al.); U.S. Pat. No. 4,734,104 (Broberg); U.S. Pat. No. 4,737,163 (Larkey); U.S. Pat. No. 4,744,802 (Schwabel); U.S. Pat. No. 4,751,138 (Tumey et al.); U.S. Pat. No. 4,770,671 (Monroe et al.); U.S. Pat. No. 4,799,939 (Bloecher et al.); U.S. Pat. No. 4,881,951 (Wood et al.); U.S. Pat. No. 4,927,431 (Buchanan et al.); U.S. Pat. No. 5,498,269 (Larmie); U.S. Pat. No. 5,011,508 (Wald et al.); U.S. Pat. No. 5,078,753 (Broberg et al.); U.S. Pat. No. 5,090,968 (Pellow); U.S. Pat. No. 5,108,463 (Buchanan et al.); U.S. Pat. No. 5,137,542 (Buchanan et al.); U.S. Pat. No. 5,139,978 (Wood); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,201,916 (Berg et al.); U.S. Pat. No. 5,203,884 (Buchanan et al.); U.S. Pat. No. 5,227,104 (Bauer); U.S. Pat. No. 5,304,223 (Pieper et al.); U.S. Pat. No. 5,328,716 (Buchanan); U.S. Pat. No. 5,366,523 (Rowenhorst et al.); U.S. Pat. No. 5,378,251 (Culler et al.); U.S. Pat. No. 5,417,726 (Stout et al.); U.S. Pat. No. 5,429,647 (Larmie); U.S. Pat. No. 5,436,063 (Follett et al.); U.S. Pat. No. 5,490,878 (Peterson et al.); U.S. Pat. No. 5,492,550 (Krishnan et al.); U.S. Pat. No. 5,496,386 (Broberg et al.); U.S. Pat. No. 5,520,711 (Helmin); U.S. Pat. No. 5,549,962 (Holmes et al.); U.S. Pat. No. 5,551,963 (Larmie); U.S. Pat. No. 5,556,437 (Lee et al.); U.S. Pat. No. 5,560,753 (Buchanan et al.); U.S. Pat. No. 5,573,619 (Benedict et al.); U.S. Pat. No. 5,609,706 (Benedict et al.); U.S. Pat. No. 5,672,186 (Chesley et al.); U.S. Pat. No. 5,700,302 (Stoetzel et al.); U.S. Pat. No. 5,851,247 (Stoetzel et al.); U.S. Pat. No. 5,913,716 (Mucci et al.); U.S. Pat. No. 5,942,015 (Culler et al.); U.S. Pat. No. 5,954,844 (Law et al.); U.S. Pat. No. 5,961,674 (Gagliardi et al.); U.S. Pat. No. 5,975,988 (Christianson); U.S. Pat. No. 6,059,850 (Lise et al.); and U.S. Pat. No. 6,261,682 (Law), the disclosures of which are incorporated herein by reference.
Abrasive articles according to the present invention are useful for abrading a workpiece in a process wherein at least a portion of the abrasive layer of a coated abrasive article is frictionally contacted with the abrasive layer with at least a portion of a surface of the workpiece, and then at least one of the coated abrasive article or the workpiece is moved relative to the other to abrade at least a portion of the surface. The abrading process may be carried out, for example, by hand or by machine. Optionally, liquid (e.g., water, oil) and/or surfactant (e.g., soap, nonionic surfactant) may be applied to the workpiece, for example, to facilitate the abrading process.
Objects and advantages of this invention are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and, details, should not be construed to unduly limit this invention.
Unless otherwise noted, all parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, and all reagents used in the examples were obtained, or are available, from general chemical suppliers such as, for example, Sigma-Aldrich Co., Saint Louis, Mo., or may be synthesized by conventional methods.
The following abbreviations are used throughout the Examples.
90° Peel Adhesion Test
A coated abrasive article to be tested is converted into an about 8 cm wide by 25 cm long piece. One-half the length of a wooden board (17.8 cm by 7.6 cm by 0.6 cm) is coated with Laminating Adhesive 1 (LA1) applied with a hot melt glue gun (commercially available under the trade designation “POLYGUN II HOT MELT APPLICATOR” from 3M Company). The entire width of, but only the first 15 cm of the length of, the coated abrasive article is coated with laminating adhesive on the side bearing the abrasive particles. The side of the coated abrasive article bearing the abrasive particles is attached to the side of the board containing the laminating adhesive coating in such a manner that the 10 cm of the coated abrasive article not bearing the laminating adhesive overhangs from the board. Pressure is applied such that the board and the coated abrasive article become intimately bonded. Operating at 25° C., the abrasive article to be tested is cut along a straight line on both sides of the article such that the width of the coated abrasive article is reduced to 5.1 cm. The resulting abrasive article/board composite is mounted horizontally in a fixture attached to the upper jaw of a tensile testing machine, commercially available under the trade designation “SINTECH 6W” from MTS Systems Corp., Eden Prairie, Minn. Approximately 1 cm of the overhanging portion of the coated abrasive article was mounted into the lower jaw of the machine such that the distance between the jaws was 12.7 cm. The machine separated the jaws at a rate of 0.05 centimeter/second (cm/sec), with the coated abrasive article being pulled at an angle of 90° away from the wooden board so that a portion of the coated abrasive article separated from the board. The force required for such separation (i.e., stripback force) is reported in kilograms/centimeter (kg/cm).
General Method for Preparation of Backing with Composite Tie Layer
The backing is coated with a solution of 98 g of water, 2 g of AZ1, 1 drop of nonionic surfactant (commercially available under the trade designation “Triton X-100” commercially available from Dow Chemical Co., Midland, Mich.). The solution was coated on the backing at using a handheld knife coater set at zero gap, and drawn across the backing at a rate of about 1 foot per second (0.3 m/sec). The coated backing is allowed to air dry.
Next, a second coating of a 100 percent solids mixture of free-radically polymerizable acidic monomer and oligomer is applied onto the AZ1-coated surface of the backing using a 4-inch (1.6-cm) wide hand-held coating knife, available from the Paul N. Gardner Company, Pompano Beach, Fla. The knife gap is set at 225 micrometers. The resultant tie layer precursor-coated backing is then passed once through a UV processor having the trade designation “UV PROCESSOR”, obtained from Fusion UV Systems, Gaithersburg, Md., using a “FUSION D” bulb at 761 Watts/inch2 (118 W/cm2) and 16.4 feet/minute (5 m/min), then heated at 120° C. for 10 to 20 minutes to give a backing having a tie layer secured thereto. The nominal coating weight of the resultant tie layer is 110 grams/m2.
Preparation of Slurry Resin 1 (SR1)
A one-gallon (4-L) plastic container was charged with 1917 g of ACR1, 19 g of PI1, 1738 g of F2, 2235 of MN2, 74 g of A1 and 17 g of A2. The resin was mechanically stirred at 25° C. for 1 hour.
General Method for Bonding an Abrasive layer to a Tie Layer
Slurry 1 is coated onto the tie layer using a handheld coating knife at a coating thickness of 2-3 mils (101 micrometers) onto a tool having precisely-shaped cavities therein as described in Example 1 of U.S. patent application Ser. No. 10/668,736 (Collins et al.), the disclosure of which is incorporated herein by reference, and then transferred to tie layer. The slurry is passed once through two UV processors obtained under the trade designation “UV PROCESSOR”, obtained from Fusion UV Systems, Gaithersburg, Md., using a “FUSION D” bulb at 761 Watts/inch2 (118 W/cm2) and 50 feet/minute (15 m/min), and then heated at 120° C. for 24 hours.
As indicated in Table 1, backings having composite tie layers were prepared according to the General Method for Preparation of Backing with Composite Tie Layer. An Abrasive Layer was then applied to the composite tie layer. The resultant coated abrasive articles were subjected to the 90° Peel Adhesion Test. In Table 1, the coated abrasives failed within the coated abrasive.
Various modifications and alterations of this invention may be made by those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.
