MX2011005166A - Acrylate color-stabilized phenolic bound abrasive products and methods for making same. - Google Patents

Abstract

Described is a color-stable abrasive article that includes a phenolic resin binder; a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one acrylate. The color-stable abrasive article is formed by a method including the steps of blending a resole and a color stabilizer to form a resole composition; contacting a plurality of abrasive particles with the resole composition; and curing the resole composition to produce the color-stable abrasive article. Thus provided are color stabilized phenolic bound abrasives and a method for making such abrasives that resist color change over time and upon exposure to high temperature and maintain the mechanical strength of a phenolic resin. Described is a color-stable abrasive article that includes a phenolic resin binder; a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one carboxylic acid ester. The color-stable abrasive article is formed by a method including the steps of blending a resole and a color stabilizer to form a resole composition; contacting a plurality of abrasive particles with the resole composition; and curing the resole composition to produce the color-stable abrasive article, Thus provided are color stabilized phenolic bound abrasives and a method for making such abrasives that resist color change over time and upon exposure to high temperature and maintain the mechanical strength of a phenolic resin. Described is a color-stable abrasive article that includes a phenolic resin binder; a color stabilizer, a colorant, and abrasive grains. The color stabilizer includes at least one acrylate. The color-stable abrasive article is formed by a method including the steps of blending a resole and a color stabilizer to form a resole composition; contacting a plurality of abrasive particles with the resole composition; and curing the resole composition to produce the color-stable abrasive article. Thus provided are color stabilized phenolic bound abrasives and a method for making such abrasives that resist color change over time and upon exposure to high temperature and maintain the mechanical strength of a phenolic resin.

Description

COLOR PHENOLIC ACCESSORY ABRASIVE PRODUCTS STABILIZED WITH ACRYLATE AND METHODS TO PREPARE THEM BACKGROUND OF THE INVENTION The term "phenolic resin" describes a wide variety of resins that are obtained from the reaction product between phenols and aldehydes. Phenols react with formaldehydes under both acidic and basic conditions. If a catalyst-based mixture of a phenol and a formaldehyde contains one or more moles of formaldehyde per mole of phenol, it will produce a thermosetting (one step) or "resol" resin. Common basic compounds that are used as catalysts for resole type resins include alkali metal hydroxides, such as sodium, potassium or lithium. Although phenolic resins obtained by catalysis with alkali metal hydroxides are commercially useful, they have an undesired tendency to darken when matured, heated or cured. There is evidence that the degree of darkening depends on the curing or the temperature of use of the resin and the time of exposure to temperature.

Phenolic resins obtained by catalysis with alkali metal hydroxides are commonly used as a component of the adhesion system of abrasive products, such as thin, coated abrasive products, REF: 220185 adhered and three-dimensional. The problem of the darkening of the resin is particularly pronounced in low-density, coated, abrasive and three-dimensional abrasive products, due to the more visible presence of the adhesion system. In addition, because the darkening increases with the temperature and time of exposure, any variation in the temperature profile of the product will cause a variation in the color of the product itself. The variation in color is particularly noticeable in light colored products, which causes products to be unacceptable for aesthetic reasons or for other reasons.

In addition, the abrasive adhesion systems may comprise dyes to identify the manufacturer, type of product, application, etc. The darkening of the resin may interfere with the desired coloration, which causes the final product to have a different color from the added colorant. For example, a resin that normally turns yellow after curing will provide a green product when combined with a blue dye or pigment. On the other hand, if the same yellow resin is combined with a dye or green pigment, normally it will be obtained simply a resin with another greenish tone.

A known method for imparting color stability of phenolic resins includes adding melanin resin and formaldehyde to the formulation. Although this provides color stability, it also confers brittleness, curing takes longer and causes mechanical weakness and, therefore, a reduced grinding performance in the finished product.

Another proposed method includes the addition to the phenolic resole of an ammonia-based salt. However, this method is not efficient enough to stabilize the color of phenolic resins that contain certain colorants, such as dyes or orange and light blue pigments.

A color stabilizer of the effective phenolic resins is needed which reduces the aforementioned problems without conferring undesired properties on the finished product.

SUMMARY OF THE INVENTION In one aspect, the present invention relates to a stable color abrasive article that includes a phenolic resin binder, a color stabilizer, a colorant and abrasive grains. The color stabilizer includes at least one acrylate.

In another aspect, the present invention relates to a method for preparing a stable color abrasive article, including the steps of mixing a resol and a color stabilizer to form a resol composition; contacting a plurality of abrasive particles with the resol composition; and curing the resol composition to produce the stable color abrasive article. The color stabilizer comprises at least one acrylate.

In yet another aspect, the present invention relates to a method for eroding a work surface, which includes applying the stable color abrasive article to a work surface with an eroding movement to remove a portion of the work surface. The abrasive product includes a binder containing a phenolic resin, a color stabilizer that includes at least one acrylate, and abrasive grains.

Therefore, stabilized color phenolic adhesion abrasives are provided and a method for preparing the abrasives that resists color change over time and after exposure to elevated temperatures and maintains the mechanical strength of a phenolic resin.

BRIEF DESCRIPTION OF THE FIGURES The following will be apparent from the following more specific description of some examples of embodiments of the invention, as illustrated in the accompanying figures, in which reference is made to the same parts in different perspectives as a reference. The figures are not necessarily to scale, instead emphasis is placed on illustrating the embodiments of the present invention.

FIG. l is a schematic representation of a cross-sectional view of one embodiment of coated abrasive tools of the invention.

FIG. 2 is a schematic representation of a cross-sectional view of another embodiment of coated abrasive tools of the invention.

DETAILED DESCRIPTION OF THE INVENTION The principles of all patents, published applications and references cited herein are incorporated by reference in their entirety. In particular, the US document. UU No. 61 / 199,472, entitled "Carboxylic Acid Ester Color-stabilized Phenolic Bound Abrasive Products and Methods for Making Same", by Everts et al., The application of which is presented simultaneously with this, is hereby incorporated herein by reference. In its whole .

The present invention relates to abrasive articles that include a phenolic resin binder whose color is stabilized with acrylates. The stabilized color abrasive article further includes a colorant and abrasive grains. As used herein, a resin or abrasive article is considered to be "stable color" if it has essentially the same color after curing it for about 8 hours at about 455 ° C (235 ° F) that after curing it for about 2 hours at approximately 455 ° C (235 ° F).

The term "phenolic resin" refers to any resinous reaction product of a phenol, such as phenol, resorcinol, alkyl substituted phenol such as cresol, xyleneol, p-ert-butylphenol and p-phenylphenol, and the like, with an aldehyde , such as formaldehyde, acetaldehyde, furfuraldehyde and the like. The term "stabilized color phenolic resin obtained by catalysis with alkali metal hydroxides" refers to a cured phenolic resin obtained by catalysis with alkali metal hydroxides whose color has been stabilized with a color stabilizing agent.

The abrasive products are characterized in that they have a phenolic resin binder, one or more acrylate color stabilizers, one or more optional colorants, abrasive grains, a supporting or protective member, and may further include curing agents, non-thermoplastic resins reactive, fillers, agents to facilitate grinding and other additives.

Structure of the abrasive article and methods to prepare it In one embodiment, the stable color abrasive article includes a phenolic resin binder, a color stabilizer and an abrasive material. The stable color abrasive article can be an adhesion, structured or coated abrasive.

The coated abrasive tools of the invention may include a substrate, an abrasive material and at least one phenolic resin binder to keep the abrasive material bonded to the substrate. As used in this, the term "coated abrasive tool" includes a non-woven abrasive tool. The abrasive material, such as abrasive grains, particles or conglomerates thereof, may be present in one layer (for example, the resin-abrasive layer) or in two layers (for example, in the first layer and in the intermediate layer). ) of coated abrasive tools. In FIG. 1 and 2 some examples of the coated abrasive tools that can be produced by the methods of the invention are shown. With reference to FIG. 1, in the coated abrasive tool 10, the substrate 12 is treated with an optional front layer 16 and an optional base layer 18. Superposed to the optional base layer 18 is the first layer 20, in which the abrasive material 14 is applied, such as grains or abrasive particles. Optionally, the intermediate layer 22 is applied to the first layer 20 and the abrasive material 14. Oving the intermediate layer 22 is the optional top layer 24. Depending on its specific applications, the coated abrasive tool 10 may or may not include the front layer 16 and / or the base layer 18. Similarly, depending on its specific applications, the coated abrasive tool 10 may or may not include the intermediate layer. 22 and / or the upper layer 24.

In FIG. 2 shows an example of coated abrasive tools that can be produced by the methods of the invention, wherein the coated abrasive tool 30 includes a single layer of binder / abrasive material 32 of an abrasive and adhesive material (s) and an anterior layer 16 optional. Optionally, base layer 18, intermediate layer 22 and upper layer 24, as shown in FIG. 1, in the coated abrasive tool 30. The coated abrasive article may include a stable color phenolic resin binder in at least one of the layers selected from the group consisting of a layer of binder-abrasive material, a previous layer, a layer of base, a first layer, an intermediate layer and an upper layer.

In embodiments including intermediate layers and top layers, such as the one shown in FIG. 1, the abrasive materials can be applied separately by gravity, electrostatic deposition, air stream or as a suspension together with the polyurethane adhesive compositions. The first layer 20 adheres the abrasive material to the surface of the substrate and can be formed by impregnating the support substrate with the phenolic resin binder without abrasive grains.

In the embodiment of FIG. 2, the support substrate can be impregnated with a resin / abrasive material suspension including an abrasive material and a resin composition including a phenolic resin binder and a color stabilizer, to form a layer of binder / abrasive material 32.

In one embodiment, a method for preparing a stable color abrasive article includes: mixing a resol and a color stabilizer comprising at least one acrylate to form a resol composition; contacting a plurality of abrasive particles with the resol composition; and curing the resol composition to produce the stable color abrasive product. In addition to the coated abrasives described above, stable color abrasive articles formed by this method include, for example, structured abrasives and adhesion abrasives.

Regarding the structured abrasives, the article is produced by any of the techniques known in the art in which the abrasive structures are formed before curing. Techniques include, for example, die cutting techniques. In one embodiment, for example, a mixture of phenolic resin binder, acrylate color stabilizer, optional colorants and abrasive grains can be contacted with a shield and a production tool, where the mixture is adhered to a surface of the protective. In this way, abrasive structures are formed which have the shape of an internal surface of the production tool.

An abrasive adhesion article can be formed by preparing a conglomerate that includes the phenolic resin binder, the acrylate color stabilizer, optional colorants and abrasive grains. The conglomerate is then shaped using any of the techniques known in the art to prepare an adhesion abrasive. Suitable techniques for preparing adhesion abrasives are described further in, for example, U.S. Pat. UU No. 5,738,696 to Wu; 5,738,697 to Wu et al .; and 6,679,758 to Bright et al .; and the US patent publication. UU No. 2003/0192258 To Simon, the complete contents of each of these are incorporated herein by way of reference.

A work surface is eroded by applying the stable color abrasive article to the work surface with an eroding motion to remove a portion of the work surface.

Phenolic resin binder The usual phenolic resins used in the present invention are the resoles, which are obtained from the reaction between phenol and formaldehyde catalyzed by an alkali metal hydroxide, with a molar ratio of phenol: formaldehyde of from about 1: 1 to about 1: 3 mol and a molar ratio of phenol: alkali metal hydroxide from about 1: 1 to about 100: 1. The color of the resole, or phenolic resin obtained by base catalysis, is stabilized by the addition of one or more acrylates. Durez Varcum resin No. 94908, manufactured by Durez Corporation, is an example of a single phase, water-based liquid phenolic resin that can be used as a binder. Other examples are provided in Table 1 below.

Table 1; Phenolic resin binders Stabilizer of color The color stabilizers employed in the present invention include the acrylates. Examples of acrylates include ethyl acrylate, epoxy acrylate, pentacrylate and trimethylolpropane triacrylate (TMPTA). Depending on the presence of other components in the formulation, the optimum amount of acrylate present in the binder formulation may vary. In certain embodiments, the percentage of the acrylate resin may be between about 2% and about 60% by weight of the phenolic resin, between about 5% and about 60% by weight of the phenolic resin, between about 10% and about 60% by weight of the phenolic resin or between about 7% and about 15% by weight of the phenolic resin.

For example, in embodiments in which the phenolic resin formulation includes peroxide or an ultraviolet photoinitiator, as further described below, the acrylate is preferably present in a greater percentage, such as between about 10% and about 60% in weigh. In embodiments in which the acrylate resin can react with the phenolic resin, the percentage of acrylate can be between about 5% and about 60% by weight.

In one embodiment, the color stabilizer consists of one or more acrylate resins with a high functionality of acrylic groups, such as pentacrylate and trimethylolpropane triacrylate (TMPTA). Other suitable resins include methyl lactate, ethyl lactate, n-propyl lactate, butyl lactate, epoxy acrylate and 2-ethylhexyl lactate.

In another embodiment, the acrylate resins are water-soluble resins, such as ethoxylated TMPTA. As described herein, the term "water-soluble" means completely miscible in water. In yet another embodiment, the acrylate resins are not water-soluble. The insoluble acrylate resin may be present in an amount ranging from about 2% to about 15% by weight. In some embodiments, the composition further includes a cosolvent, such as glycol. Optionally, an amount of vitamins E and C ranging from 1% to 20% by weight of the resin can be added.

There is evidence that acrylates confer stability to the color of phenolic resins because they react with phenoxy radicals that would otherwise oxidize and form dark colored quinine structures. Reactions 1 and 2 represent an example of the mechanism that is believed to take place when there is no acrylate in the phenolic resin, while reaction 3 represents an alternative to reaction 2 that occurs when there is an acrylate.

In reaction 1, the phenol is ionized in basic medium and forms a phenolate ion and the resonant structure of the corresponding phenoxy radical.

In reaction 2, the phenoxy radical rapidly undergoes oxidation in basic medium to form a dark colored quinone structure.

In reaction 3, the trimethylolpropane triacrylate reacts with the phenoxy radical and prevents the formation of the dark colored quinine residue, which provides a stable colored resin. It has also been shown that the incorporation of the acrylate repeating unit in the phenolic resin network confers hardness to the polymer.

Colorant The abrasive product may include a colorant, for example, dyes or pigments. Generally, a portion of the dye may be visible through the cured resin. In some embodiments, a portion of the dye is included in the cured resin, in an optional support substrate and / or in a coating between the optional support substrate and the cured resin. In particular embodiments, the colorant may include polycyclic organic dyes, monoazo organic dyes, diazo organic dyes, organometallic complexes, inorganic pigments such as oxides or metal complexes. The dyes can be perinone, anthraquinone, azo complex dyes and thioindigoids.

A fluorescent dye is a dye or pigment that contains a fluorescent organic molecule. For a detailed description of fluorescent dyes, refer to "Color Chemistry: Synthesis, Properties, and Applications of Organic Dyes and Pigments" by H. Zollinger, 2nd edition, VCH, New York, 1991, whose principles are incorporated in its whole to the present by way of reference. As used herein, a fluorescent dye may be, for example, a xanthene, thioxanthene, fluorene (eg, fluoresceins, rhodamines, eosins, phloxins, urans, succineins, sacareins, rosamines, and rholes), naphthylamine, naphthylimide, naphtolactam , azalactone, methino, oxazine, thiazine, benzopyran, coumarin, amino ketone, anthraquinone, isoviolantrone, anthrapyridone, pyranine, pyrazolone, benzothiazene, perylene or thioindigoide. More preferably, a fluorescent dye is selected from the group consisting of xanthenes, thioxanthenes, benzopyrans, coumarins, amino ketones, anthraquinones, isoviolantrones, anthrapyridones, pyranines, pyrazolones, benzothiacenes, thioindigoids and fluorenes. Even more preferably, the fluorescent dye is a thioxanthene or thioxanthene.

A person skilled in the art will understand that, in the case of many dyes that can be purchased from commercial suppliers, it may be that the specific chemical structure of the individual derivatives within a class, for example, thioxanthene derivatives, is not found. publicly available. Therefore, specific fluorescent dyes are usually referred to by their color index (IC) name, as defined in "Color Index International," 4th Edition, American Association of Textile and Color Chemicals, Research Triangle Park , NC, 2002. The color index is also available online at www.colour-index.org. All principles of the color index are incorporated herein by way of reference.

Examples of preferred fluorescent dyes include I.C. Orange solvent 63 (Hostasol red GG, Hoechst AG, Frankfurt, Germany), the I.C. Yellow solvent 98 (Hostasol yellow 3G, Hoechst AG, Frankfurt, Germany) and the I.C. Orange Solvent 118 (Orange FL SFR, Keystone Aniline Corporation, Chicago, Illinois).

The amount of colorant to be used depends on the particular characteristics of the intended use, the characteristics of the colorant, the other components of the composition and the like. The person skilled in the art will know how to assess these factors to determine the amount of colorant for a particular use. Typically, the amount of colorant will be a fraction of the weight of the total composition of between about 0.01 and about 2%, more preferably between about 0.05 and about 0.5% and even more preferably about 0.2%.

In specific embodiments, the colorant is a red, orange, yellow, green, blue, indigo or violet dye. In specific embodiments, the dye is fluorescent, for example, a fluorescent red, fluorescent orange (jblaze orange), fluorescent yellow, fluorescent green or the like.

The colorant can be used to identify the abrasive product, for example, to indicate the trademark, to use indications such as wet, dry, wood, metal or the like, to identify the grain size, or the like.

Abrasive grains The abrasive grains may include any type of grains or a combination thereof, including, but not limited to, silica, alumina (fused or sintered), zirconia, zirconia / alumina oxides, silicon carbide, garnet, diamond, boron nitride. cubic (CBN), silicon nitride, cerium oxide, titanium dioxide, titanium diboride, boron carbide, tin oxide, tungsten carbide, titanium carbide, iron oxide, chromium oxide, flint and emery. For example, the abrasive grains may be selected from a group consisting of silica, alumina, zirconia, silicon carbide, silicon nitride, boron nitride, garnet, diamond, alumina and zirconia fused together, cerium oxide, titanium diboride , boron carbide, flint, emery, alumina nitride and a mixture of these. In some cases, dense abrasive grains comprising mainly alpha alumina and / or gamma alumina may be used.

Abrasive grains may also include grains of abrasive conglomerates, which are also known as conglomerate abrasive grains. The grains of abrasive conglomerates include abrasive particles adhered to each other with a particle binder material. The abrasive particles present in the grains of abrasive conglomerates may include one or more of the abrasives known for use in abrasive tools such as, for example, silica, alumina (fused or sintered), zirconia, zirconia / alumina oxides, carbide silicon, garnet, diamond, cubic boron nitride (CBN), silicon nitride, cerium oxide, titanium dioxide, titanium diboride, boron carbide, tin oxide, tungsten carbide, titanium carbide, iron oxide, chromium oxide, flint, emery and combinations of these. The abrasive particles can have any size or shape. The grains of abrasive conglomerates can be adhered to each other with a particle binder material such as, for example, a metallic, organic or glassy material, or a combination of the materials. Abrasive conglomerate grains suitable for use in the present invention are further described in U.S. Pat. UU No. 6,797,023 to Knapp et al., The contents of which are hereby incorporated by reference in their entirety.

The abrasive grains may have one or more particular shapes. Examples of particular shapes include bars, triangles, pyramids, cones, solid spheres, hollow spheres and the like. Alternatively, the abrasive grains can be randomly shaped.

The abrasive grains usually have an average grain size of less than 2000 microns, such as, for example, less than about 1500 microns. In another example, the abrasive grain size is less than about 750 microns, such as less than about 350 microns. In some embodiments, the abrasive grain size may be at least 0.1 microns, such as from about 0.1 microns to about 1500 microns and, more usually, from about 0.1 microns to about 200 microns or from about 1 micron to about 100 microns. The grain size of the abrasive grains is usually specified as the largest dimension of the abrasive grain. Generally, there is a range of distribution of grain sizes. In some cases, the grain size distribution is strictly controlled.

Supporting member / protector The abrasive articles may include a support or protector member. The protector can be flexible or rigid. The protector can be made of any number of different materials, including those conventionally used as protectors in the manufacture of coated abrasives. Suitable protectants can include polymeric films (eg, a prepared film), such as polyolefin films (e.g., polypropylene including biaxially oriented polypropylene), polyester films (e.g., polyethylene terephthalate), polyamide films or cellulose ester films; metal sheets; tights; foams (e.g., polyurethane foam or natural sponge material); fabrics (eg, woven, non-woven, woolen, sewn or quilted, or fabrics made of fibers or yarns comprising polyester, nylon, silk, cotton, polycotton or rayon); paper; vulcanized paper; vulcanized rubber; vulcanized fiber; non-woven materials; a protector treated of these; or any combination of these.

The protector can have at least one of the following layers: a saturating layer, a base layer or a previous layer. The purpose of these layers is usually to seal the protector or protect the threads or fibers of the protector. If the protector is a cloth material, at least one of these layers is usually used. The addition of the base layer or the above layer can additionally generate a "smoother" surface either on the front or back of the protector. Other optional layers known in the art may be used (eg, a binder layer; see U.S. Patent No. 5,700,302 to Stoetzel et al., The contents of which are incorporated herein by reference in their entirety). reference mode).

In some embodiments, the abrasive articles are designed to be used as quality grinding materials and, therefore, a very smooth surface is preferred. Examples of smooth surface protectors include finely calendered paper, plastic films or fabrics with smooth surface coatings.

The protector can have antistatic properties. The addition of an antistatic material can reduce the tendency of the abrasive article to accumulate static electricity when sanding wood or wood-like materials. For more details on antistatic protectors and treatments, see, for example, US Pat. UU Nos. 5,108,463 to Buchanan, et al .; 5,137,542 to Buchanan, et al .; 5,328,716 to Buchanan; and 5,560,753 to Buchanan, et al., the contents of which are hereby incorporated by reference in their entirety.

The protector may include a fibrous reinforced thermoplastic as described, for example, in U.S. Pat. UU No. 5,417,726 to Stout et al., Or a tape without splices or ends as described, for example, in U.S. Pat. UU No. 5,573,619 to Benedict et al., The contents of which are hereby incorporated by reference in their entirety. Also, the shield can include a polymeric substrate with anchoring rods projecting therefrom, such as those described, for example in U.S. Pat. UU No. 5,505,747 to Chesley et al., The contents of which are hereby incorporated by reference in their entirety. Similarly, the protector may include a loop fabric, such as that described, for example, in U.S. Pat. UU No. 5,565,011 to Follett et al., The contents of which are hereby incorporated by reference in their entirety.

Other components The abrasive articles of the present invention can also include other different components, such as curing additives, non-reactive thermoplastic resins, fillers, milling facilitating agents and other additives.

In some embodiments, the abrasive article includes a curing additive, such as a photoinitiator, which generates free radicals when exposed to radiation, for example, UV radiation. The free radical generators can include organic peroxides, azo compounds, quinones, benzophenones, nitroso compounds, acryl halides, hydrozones, mercapto-type compounds, pyrilium-type compounds, triacrylimidazoles, bisimidazoles, chloroalkyltriazines, benzoin ethers, ketals of benzyl, thioxanthones and acetophenones, including derivatives of the compounds. Among these, the most commonly used photoinitiators are benzyl ketals such as 2,2-dimethoxy-2-phenylacetophenone (marketed by Ciba Specialty Chemicals under the trademark IRGACURE * 651) and acetophenone derivatives such as 2,2 -dietoxyacetophenone ("DEAP", marketed by First Chemical Corporation), 2-hydroxy-2-methyl-1-phenyl-propan-1-one ("HMPP", marketed by Ciba Specialty Chemicals under the trademark DAROCUR® 1173), 2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone, (marketed by Ciba Specialty Chemicals under the trademark IRGACURE * 369); and 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, (marketed by Ciba Specialty Chemicals under the trademark IRGACURE * 907).

The abrasive articles may include a non-reactive thermoplastic resin such as, for example, polypropylene glycol, polyethylene glycol, and polyoxypropylene-polyoxyethene block copolymer.

Fillers include organic fillers, inorganic fillers and nanofillers. Examples of suitable fillers include, without limitation, metal carbonates such as calcium carbonate and sodium carbonate, - silicas such as quartz, glass microspheres, glass bubbles; silicates such as talc, clays, calcium metasilicate; metal sulfates such as barium sulfate, calcium sulfate, aluminum sulfate; metal oxides such as calcium oxide, aluminum oxide; aluminum trihydrate, and combinations of these.

The abrasive articles may include an agent to facilitate grinding that increases milling efficiency and cutting speed. Some useful agents for facilitating grinding may be inorganic, such as halide-type salts, for example, sodium cryolite and potassium tetrafluoroborate; or of organic base, such as chlorinated waxes, for example, polyvinyl chloride. In another particular embodiment, the abrasive article includes cryolite and potassium tetrafluoroborate with a particle size ranging from about 1 micron to about 80 micron, more usually between about 5 micron and about 30 micron. Generally, the concentration of the agent to facilitate grinding in the first layer is less than about 50% by weight, for example, the concentration of the agent for facilitating grinding is usually from about 0.1 wt% to 50 wt%, and more usually it is from about 10% by weight to 30% by weight (all% by weight are based on the weight of the first layer including the abrasive grains).

Examples of additional additives include coupling agents such as "silane-type coupling agents, for example, A-174 and A-1100 marketed by Osi Specialties, Inc., titanate and zircoaluminates; antistatic agents such as graphite, carbon black and the like; suspending agents such as fumed silica, for example, Cab-O-Sil M5, Aerosil 200; anti-caking agents such as zinc stearate and calcium stearate; lubricants such as wax, PTFE powder, polyethylene glycol, polypropylene glycol and polysiloxanes; wetting agents; pigments; dispersants; and defoamers.

EXAMPLES In the following, the invention will be described specifically and in more detail by the following examples, which are not intended to be limiting.

Example 1; Four phenolic resin compositions were formulated. Each of the compositions contained the compounds shown in Table 2.

Table 2 In addition, each of the formulations 2-4 contained the same amount of a different acrylate. Table 3 below indicates the amount of acrylate present in each of the formulations.

Table 3 No. of Acrylate Type Quantity Color after test added to that of curing resin acrylate formulation for 10 hr to phenolic present 250 ° F (121.1 ° C) 1 none 0% black 2 Epoxyacrylate (Ebecryl 10% red 3700) 3 Pentacrylate 10% light brown- yellow 4 TMPTA 10% light brown- yellow The table shows that the compositions containing the acrylates were resistant to darkening upon exposure to heating during curing. In particular, it was shown that pentacrylate and TMPTA were the most effective for color stabilization of the phenolic resin.

Equivalents Although this invention has been particularly demonstrated and described with references to the examples of the embodiments thereof, it will be understood by those skilled in the art that various changes may be made in the form and details of the present without departing from the scope of the invention. which is encompassed in the nded claims.

It is noted that, in relation to this date, the best method known to the icant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (15)

CLAIMS Having. described the invention as above, claimed as property contained in the following claims:

1. A stable color abrasive article, characterized in that it comprises: a) a binder comprising a phenolic resin; b) a color stabilizer that includes at least one acrylate; Y c) abrasive grains.

2. The stable color abrasive article according to claim 1, characterized in that the phenolic resin is a resole.

3. The stable color abrasive article according to claim 1, characterized in that the color stabilizer is present in an amount of between about 2% and about 60% by weight.

4. The "stable" color abrasive article according to claim 1, characterized in that the color stabilizer is present in an amount of between about 7% and about 15% by weight.

5. The stable color abrasive article according to claim 1, characterized in that the color stabilizer is an acrylate selected from the group consisting of ethyl acrylate, epoxy acrylate, pentacrylate and trimethylolpropane triacrylate (TMPTA).

6. The stable color abrasive article according to claim 1, characterized in that the color stabilizer includes the ethoxylated trimethylolpropane triacrylate acrylate.

7. The stable color abrasive article according to claim 6, characterized in that it also comprises a glycolic cosolvent.

8. The stable color abrasive article according to claim 1, characterized in that the color stabilizer includes a water-insoluble acrylate resin present in an amount of between about 2% and about 15% by weight.

9. The stable color abrasive article according to claim 5, characterized in that the acrylate is present in an amount of between about 5% and about 60% by weight.

10. The stable color abrasive article according to claim 5, characterized in that the acrylate is present in an amount of between about 10% and about 60% by weight.

11. The stable color abrasive article according to claim 5, characterized in that the acrylate resin is capable of reacting with the phenolic resin.

12. The stable color abrasive article according to claim 1, characterized in that it does not show any visually perceptible color change after about 8 hours of curing at about 455 ° C (235 ° F) in relation to the same article after about 2 hours of curing at about 455 ° C (235 ° F).

13. The stable color abrasive article according to claim 1, characterized in that the phenolic resin binder and the color stabilizer are present in at least one layer selected from the group consisting of a layer of binder-abrasive material, an anterior layer, a base layer, a first layer, an intermediate layer and an upper layer.

14. A method for preparing a stable color abrasive article, characterized in that it comprises the steps of: a) mixing a resol and a color stabilizer comprising at least one acrylate to form a resol composition; b) contacting a plurality of abrasive particles with the resol composition; Y c) curing the resol composition to produce the stable color abrasive article.

15. A method for eroding a work surface, characterized in that it comprises applying the stable color abrasive article to a work surface with an eroding movement to remove a portion of the work surface, where the abrasive product includes: a) a binder comprising a phenolic resin; b) a color stabilizer that includes at least one acrylate; Y c) abrasive grains.