MXPA97002404A - Abrasive articles with lubricant encapsul - Google Patents

Abstract

Abrasive articles having an encapsulated lubricant are described. In one aspect, the articles are characterized by a base substrate comprising a plurality of polymeric fibers adhered to each other at mutual points of contact, the substrate having a basis weight within the range of 20 to 10,000 g / m2, beads of adhesive adhered to the substrate and a plurality of lubricant capsules adhered to the substrate, the capsules comprise a continuous cover with the lubricant therein, and the shell comprises a cured thermosetting resin. In another aspect, a composite abrasive article is characterized by at least two layers of the aforementioned abrasive article, compressed together and adhered by a binder, the composite article has a flexural modulus of not more than 100 Kgf / c.

Description

ABRASIVE ARTICLES WITH ENCAPSULATED LUBRICANT DESCRIPTION OF THE INVENTION l? present invention relates to acrylic articles. In particular, the present invention relates to with abrasive articles containing a lubricant encapsulated therein. Surface treatment in surface finishing operations, for example, can be done using: any of a variety of items for l? surface treatment to achieve the desired treatment. 1. The use of non-woven articles in such applications is known. When non-woven articles are used in the treatment (for example, finishing) of metal surfaces, a liquid lubricant or i is applied; solid to the non-woven article to improve the abrasion power of the article and to avoid "abrasive burning" or discoloration of the treated surface caused by the heat generated during the surface treatment operation. The application of lubricant to the article does not 2 tissue or to the surface, it can be done in various ways. For example, a lubricant may be applied directly to the non-woven article or to the surface to be treated at various intervals during the finishing operation. Such application of the lubricant, however, is .3 unsatisfactory because the lubricant may splash during operation, especially under the operation of REF: 24307 high speed surface treatment equipment. In addition, the lubricant must be applied frequently to maintain the desired level of lubrication. It is desirable, therefore, to provide an article, 3 which can be used in the surface treatment of metal surfaces and the like, wherein the article can be used without separate application of the lubricant. Preferably, it is desirable to provide an articulation for the surface treatment comprising i ') a non-woven substrate having a lubricant source incorporated within the substrate, so that the lubricant will automatically be available during the use of the article in the operations of surface treatment. The literature describes a variety of articles 1. 3 for surface treatment, which include encapsulated lubricants and the like. Japanese Patent Laid-open Publication No. Sho 62-152679, discloses abrasive materials, which include a lubricant encapsulated in a wrapper:? Cast of inorganic substances. The envelope: Ü described is porous, with pore sizes of several tenths to several hundredths of angstrom, so that a liquid lubricant may not be completely sealed in the capsule ("Recent Microincapsulation Technology" p.131, edited by the Integrated Technology Center).

Japanese Utility Model Open Publication Nos. Sho 63-32761 and 63-32762, discloses non-abrasive materials that include a lubricant encapsulated in an acrylic resin wrap. The acrylic resin has a low vitreous transition temperitura, so it requires e. use of a crosslinker and shows poor resistance to solvent and heat, due to its low crosslink density. Consequently, the acrylic resin shell can be easily dissolved by an organic solvent or melted by the heat normally used in the manufacture of nonwoven abrasive materials. Japanese Utility Model Open Publication No. Sho 63-32763 discloses non-woven abrasive materials with a lubricant encapsulated in glass capsules. Glass capsules are produced by melting by heat a glass at a temperature higher than its melting point, potentially causing the lubricant to decompose during the preparation of the capsules. In addition, the use of glass presents a potential risk to safety. US Pat. No. 3,502,453 (Baratto) discloses a resin-bonded disk comprising tern resin capsules containing a lubricant to reduce friction by polishing. The disc, however, it is not suitable for precision abrasion operations, due to its relative inflexibility. In addition, the lubricant containing capsules may not break in a uniform manner, thus decreasing lubricant efficiency in several applications. In accordance with this, it is desirable to provide a deformable article for surface treatment, having an encapsulated lubricant, which provides lubrication. satisfactory during the surface treatment operations without the need for lubricants and without exhibiting the aforementioned problems inherent in the various articles of the prior art. Preferably, such a deformable article for surface treatment, comprises a nonwoven substrate with the aforementioned encapsulated lubricant attached ":" to the same, wherein the lubricant is effective in preventing burning by abrasion during use and wherein the article eet an excellent abrasion power.The present invention provides an abrasive article with an encapsulated lubricant. articles of the The invention exhibits excellent abrasion power, while avoiding abrasive burning during surface tightening operations. In one aspect, the invention provides an abrasive article, characterized by: ur base substrate comprising a plurality of polymeric fibers adhered to each other at iruccant concave points, the substrate having a basis weight in the range of 20 to 10,000 g / m2; 3 abrasive grains adhered to the substrate; and a plurality of lubricant capsules comprising a cover adhered to the substrate and containing the lubricant therein, the cover comprising a cured thermosetting resin. l? The fibers of the substrate are preferably fibers classified according to their length, having a preferred length of about 10 to 50 mm and a denier dentco of the range of 5 to 30. The fibers may comprise any of a variety of elastic materials , ': • conformable .; and durable. Preferred fibers comprise nylon 6,6. The substrate is preferably a non-woven substrate or a void volume in the range of about 40 to 99%. As mentioned, the articles include ur encapsulated lubricant, where the lubricant : •) is contained within the cover comprising a cured thermosetting resin. The preferred resin is highly resistant to heat and solvent degradation and suitable resins can be selected from epoxy resins, urea resins, melamine resins, phenol resins and polyamide resins. Preferably, the resin is a ream of urea or melamine. The capsules may also comprise an additional layer of a film surrounding the thermosetting resin to further increase the solvent and / or heat resistance. The The film comprises a metal or an oxide thereof, wherein the metal may be copper, nickel, zinc, silver, lead or tin. As used herein, certain terms and phrases will be understood to have the meaning set forth herein. "Gap Volume" means the volume of the open space within an article (expressed as a percentage, and is determined according to the following equation: Volume of Gaps (%) = [1 - (density of article not ) te] left / density of the underlying fibers)] x 100"Thermosetting resin" means a polymeric resin capable of crosslinking. "Fibers" refers to strand-like structures comprising the materials / •) as set forth herein. "Fibers classified according to their length" means fibers of discrete lengths as further described herein. "Lubricant capsules", refers to an encapsulated lubricant comprising a continuous coating of one or more polymeric materials as described herein and containing a volume of lubricant therein. "Vitre transition point" or "Tg", means the temperature at which the material changes from the vitreous state to the plastic state, as measured in a differential scanning calorimeter "DSC 4", available from Perkin-Elmer Corporation. "Nominal Density" of a non-woven article, means the basic weight of a non-woven article by its thickness, according to the formula Nominal density (g / cm3) = [basic weight g / cm2) xlO'V thickness (c)] In another aspect, the invention provides a composite abrasive article, comprising at least two layers of a non-woven abrasive article, as described above, compressed together and adhered by a binder, the composite article having a flexural modulus of no more than 100 kgf / cm2. Additional details of the invention will be more fully appreciated by those skilled in the art with consideration of the rest of the description.,. The articles of the invention include a base substrate in which additional components of the article are adhered. The preferred base substrate is a nonwoven fabric comprising a plurality of polymer fibers. The preferred substrate is one, which is easily conformable to the surface of a desired part and wherein the abrasive grains adhere easily to its fibrous surface. Preferably, such a substrate is not expensive and light in weight. Although continuous filaments can be used in? manufacturing of the substrate, the preferred substrate comprises a plurality of fibers classified according to their length having a length within the range of 10 to 50 mm and a linear density within the range of 5 to 30 denier. The fibers of the substrate may comprise any of a variety of materials suitable for the manufacture of fibers. Exemplary materials are polymeric materials such as polyamide, polyester, polypropylene, polyethylene, polysulfone, acrylic and polyvinyl chloride and the like. The fibers of the substrate can be a mixture of fibers comprising any of one or more of the above materials. In addition, roofing substrates with fibers comprising copolymers of the above materials, can be incorporated into the substrate, and the denier blends of fibers and lengths of _; fibers, are also contemplated within the scope of this invention. those skilled in the art will appreciate that the preferred materials for the substrate can vary depending on the desired properties. The fibers of > Polyester, for example, are preferred because of their excellent mechanical strength, as well as their resistance to heat and wear. Polyamide fibers (eg, nylon 6,6) are more preferred, due to their heat resistance, elasticity and formability. In addition, resins 3 conventional used in the manufacture of non-woven abrasives, especially phenolic resins, adhere well to nylon 6,6 fibers. The non-woven base substrate, preferably has a void volume in the range of 40% to 99%. o At void volumes of less than 40%, it becomes difficult to achieve effective penetration of the abrasive grain and binder into the substrate during the manufacture of the article. At a void volume greater than 99%, the mechanical strength and wear resistance of the resulting abrasive materials may be unacceptable for certain applications. The void volume of the non-woven substrate is expressed as a percentage according to the following equation: i Gap volume (%) = [1 - (density of article no tissue / density of the underlying fibers)] x 100 Preferably, the thickness of the non-woven fabric is within the range of 1 to 50 mm. If he If the thickness of the substrate is less than 1 mm, the mechanical strength of the resulting article may be poor. If the thickness is greater than 50 mm, it becomes increasingly difficult to apply the abrasive grains and the ream binders within the non-woven substrate. Due to the ease of preparation and the resulting uniformity of the finished articles, a non-woven substrate having a thickness of 2 to 10 mm is more preferred. S? it employs a binder to adhere the fibers of the base substrate not woven to each other at their mutual points of contact and to adhere the abrasive grain and the encapsulated lubricant, discussed below, to the fibers of the substrate. Any of a variety of binders can be used in the manufacture of the articles according to the invention. Epoxy resins are useful in the manufacture of the articles of the invention, due to their high reactivity and mechanical strength. Commercially available epoxy resins include those available under the trade designations "DER-331" and "DER-332" from Dow Chemical Co. Urethane resins, due to their high reactivity and binding strength, are also suitable for use in the articles of the invention. Suitable commercial urethanes include those available under the trade designations "UP-310" and "UP-340", available from Asahi Denka K.K of Japan. In addition, water-soluble urethane resins, and water-soluble ecbxic resins can be used, such as those described by Krishnan et al. in U.S. Patent No. 5,306,319. More preferably, the finished articles of the invention will have a flexural modulus of not more than 100 kgf / crtr, and the preferred binders are those capable of providing such articles. In this regard, phenolic resins are most preferred. Additionally, phenolic resins exhibit excellent heat resistance, abrasion resistance and mechanical strength. Commercially available phenolic resins suitable for use in the invention include those available under the trade designations "Shonol BRL-105" and "Shonol BRL-107" available from Showa Kobunshi K.K. from Japan. The abrasive grains can be used in the articles of the invention. The grains used herein may be selected from any of a variety of grains available to those in the art. If the item is to be used in more aggressive abrasive applications, grains comprised of a hard material can be used, such as grains of sharpening stones, including silicon carbide, aluminum oxide, chromium oxide, emery and flint, either alone or in combination with one another. Of the above materials, those having a JIS No. of 36 to 10000 (an average grain size of 500-0.6 μm) are particularly preferred for precision abrasion applications. Of course, the invention is not limited to the use of -? The above grains, and those skilled in the art, will appreciate that other materials may be used in the articles described herein, including those comprised of softer materials for less aggressive polishing. In addition, the articles of the • > invention can be made without abrasive grain for applications where the substrate coated with binder can have the required hardness, such as in polishing applications, for example. LIS abrasive grains can be employed in an amount in the range of 10 to 1000 parts by weight, and preferably, 30 to 500 parts by weight, based on 100 parts by weight of the base substrate. Although the weight of the grains used may also be outside of the above ranges, the use of grain in an amount less than 10 - > parts by weight, will typically decrease the abrasion power of the article below acceptable limits for some applications. Similarly, if the amount of grain in the article is greater than 1000 parts by weight, the abrasive grains may not properly bind to the fibers of the substrate, resulting in the loss of a significant portion of the grains during use. The articles of the invention include a lubricant capsule attached to the fibers of the substrate by the 3 aforementioned binder. The lubricant capsule comprises a shell in the form of a continuous shell and a core substance comprising a lubricant contained within the shell. The preferred lubricant capsule for use in the invention is •) prepared to have resistance to the solvent, as well as resistance to heat. The wrapping of the capsules of - lubricant of the present invention, preferably will have a vitreous transition point (Tg) high enough to avoid softening during manufacturing .3 of the non-woven abrasive materials, while allowing a softening of the capsule during an abrasive application of the finished article in order to release the encapsulated lubricant during use. In general, u ::? glass transition point of at least 160 ° C M is preferred, due to the temperatures employed in the drying step used in the preparation of a non-woven abrasive. Materials that have a vitreous transition point of more than 180 ° C are preferred for abrasive materials to be used at high speed.

In a preferred manner, the lubricant capsule comprises a crosslinked polymer due to the ability of such materials to meet the aforementioned solvent resistance requirements. Examples of suitable polyether polymers include: epoxy resins, urea resins (eg, urea-formaldehyde resin, urea-acetaldehyde resin, urea-propionaldehyde resin, and urea-butylaldehyde resin), melamine resin (eg. example, melamine-formaldehyde resin, melamine-acetaldehyde resin, melamine-propionaldehyde resin and melamine-butylaldehyde resin), phenol resin (eg, phenol-formaldehyde resin, phenol-acetaldehyde resin, phenol-3-alkyldehyde resin, phenol-butylaldehyde resin, xyleneol-formaldehyde resin, xyleneol-acetaldehyde resin, xyleneol-propionaldehyde resin and xyleneol-butylaldehyde resin), and polyamide resin. Preferred materials for the manufacture of the continuous cover of the lubricant capsule, comprise a polymeric component and a suitable crosslinking material. Preferably, the molar ratio between the polymer component such as urea, melamine and phenol and the like, and the crosslinking component (eg, formaldehyde), is within the range from 1: 1.2 to 1: 1.7. The relationships within this range will provide satisfactory reactivity and a low amount of unreacted, residual crosslinking material. Among the resins exemplified above is a urea resin and a melamine resin, they are particularly preferred, due to their excellent solvent resistance. The most preferred resin for making the capsules is the urea resin. Suitable lubricants for inclusion in lubricant capsules include petroleum derived lubricants (eg, paraffin wax), synthetic resin lubricants (eg, silicone oil, polymerized olefin oil, diester oil, polyoxyalkylene glycol) , And hydrogenated hydrocarbon oil, etc.), and fatty acids (for example, stearic acid and myristic acid, etc.). Lubricating capsules can be included in the non-woven articles of the invention in an amount of 1 to 100 parts by weight, based on 100 parts by weight of non-woven fabric. If the quantity of lubricant capsules is less than 1 part by weight, satisfactory lubrication may not be provided. If the number of lubricant capsules exceeds 100 parts by weight, the amount of abrasive grain, which is capable of adhering to the base substrate, may decrease with a corresponding decrease in the abrasion power of the finished article. In order to balance the abrasion power and the lubrication, the quantity of lubricant capsules in the finished article is preferably within the range of 5 to 50 parts by weight and, more preferably, within the range of 10 to 30. parts. The lubricant capsules employed in the present invention can be prepared by the following procedure: A suitable lubricant is fed into an acid solution of a resin. The temperature and the agitation speed of the mixture is controlled in a known manner, so that the lubricant can form drops of a suitable size. Then, the resin cross-linking reaction is initiated to provide lubricant-containing capsules therein. In a preferred lubricant capsule, formalin, urea and a pH adjuster are placed in a suitable reaction vessel, and the temperature of the mixture is controlled within the range of from 25 to 90 ° C. The mixture is stirred for 1 to 24 hours to give a water-soluble urea-formaldehyde resin. The temperature of the resin solution is then adjusted to exceed the melting point of the lubricant rail (eg, 60 to 90 ° C), and the lubricant is added with stirring and melting. An acid having a pH of 3 to 6 (eg, citric acid) is added to catalyze the polymerization reaction, followed by a constant agitation of 1 to 10 hours at a stirring speed of 300 to 5000 rpm, to thereby form lubricant capsules suitable for use in the articles of the present invention. A preferred curing catalyst for use in the above reaction process is a weak acid, preferably those which have a pH within the range of 3 to 6. In the above pH range, the condensation reaction will proceed faster than the addition reaction of formalin to urea, so that the crosslinking reaction is carried out more efficiently. As a result, the envelope of the capsules will have a higher density of reticulation and improved solvent and heat resistance. In addition, a weak acid can be handled more safely than a strong acid, and any weak acid left in the lubricant capsule will present less damage to the: >I think it could be a strong acid. Citric acid, boric acid, malic acid, phosphoric acid and the like are suitable for use as curing catalysts. In another aspect of the invention, the outer surfaces of the lubricant capsules are optionally coated with a thin metal or metal oxide film to further improve the solvent resistance and abrasion power of the finished abrasive articles. The metal covers useful in the present invention comprise thin coatings of metals or metal oxides of nickel, copper, zinc, silver, lead or tin. The coatings can be applied to the lubricant capsules in a manner known per se by conventional vacuum evaporation, electronic deposition or chemical deposition, for example. Lubricant capsules of a size smaller than the space between the fibers of the base substrate can be used. In metal finishing applications, the linear density of the fibers used in the nonwoven base substrate will preferably be in the range of 5 to 30 denier. In these articles, the preferred grain size for the lubricant capsules is 5 to 300 μm.

When the grain size of the capsules is less than 5 μm, the capsules will be more difficult to break during an abrasive application. When the grain size of the lubricant capsules is greater than 300 μm, the capsules can interfere with the ability of the abrasive grains and the binder to effectively enter the interior areas of the nonwoven base substrate. In order to allow homogenous dispersion of the lubricant capsules within the non-woven fabric, a grain size of 20 to 150 μm is preferred, and in order to allow uniform destruction of the lubricant capsules during an application of For the finished articles, a grain size within the range of 10 to 20 μ is more preferred.

The continuous cover or envelope of the lubricant capsules, preferably has a thickness in the range from 0.5 to 20 μm. At a thickness less than 0.5 μ, the resistance to heat and solvent may be poor. If the thickness is beyond 20 μm, the capsules can be very hard to break during an abrasive application. To allow for uniform destruction of the capsules during use, a thickness in the range of 1 to 10 μ is preferred, and a thickness in the range of 2 to 7 μm is more preferred. The abrasive articles of the invention can be prepared in the following procedure. A pre-bonded non-woven base substrate, comprising polyamide fibers and the like, is treated with a mixture containing abrasive grain, binder (e.g., phenolic resin), solvents (e.g., ethylene alicyclic ponoethyl ether acetate) and capsules of lubricant. The above mixture can be applied in a known manner, using an immersion method, a two-roll coater or by spraying. Since the mixture will contain an oganic solvent, lubricant capsules, which are resistant to solvent, are preferred. Alternatively, commercially available nonwoven abrasive materials may be used, and a mixture of lubricant capsules in a suitable binder may be applied to the non-woven article. Commercially available abrasive materials, suitable, include those made of conventional nonwoven materials, comprising polyamide fibers or polyester fibers with abrasive grains adhered to the fibers with a suitable binder. Preferred are those articles having abrasive particles of a JIS No. 36 to 10000, such as silicon carbide, aluminum oxide, chromium oxide, emery and flint. The exemplary material of this type of non-woven abrasive material is that available under the commercial designation "Scotch-Brite" from Minnesota Mining and Manufacturing Company of St. Paul, Minn., USA. After applying the lubricant capsule and the binder, the article is heated in an oven at about 160 ° C for about 15 minutes to dry the organic solvent and to solidify a binder. The eminent non-woven abrasive article thus obtained, opened, will preferably have a basic weight in the range of 20 to 10,000 g / m2, with sufficient flexibility to conform to the contours along the surface of the piece. Preferably, the basic weight of the article will be in the range of 40 to 6000 g / m2, and more preferably, 100 to 5000 g / m2. The article of the invention will have a nominal density within the range of about 0.01 to 1.00 g / cm3, preferably 0.02 to 0.60 g / cm3, and more preferably, 0.05 to 0.50 g / cm. In another aspect of the invention, the items described above, may be further processed into disks attached in a known manner. Rolled disks, for example, can be provided by taking a single continuous sheet of the non-woven article described above and giving it the shape of a roll or a disc by rolling the article over a core. Alternately, the unit discs can be provided by cutting the nonwoven abrasive articles provided above into a plurality of individual pieces (e.g., frames). The individual pieces are stacked one on top of the other, compressed and laminated together by means of the application of pressure and heat. In the compression of the sheets of non-woven articles, the nonwoven abrasive materials are preferably compiled at a density of 1 to 20 times the density of the materials in their uncompressed state and subjected to heat molding for 4 hours at a time. elevated temperature, usually at 135 ° C. The laminates thus treated can then be cooled and cut to provide a joined disc. Additionally, the non-woven abrasive articles of the invention can be used in the manufacture of shaving brushes.

Alternatively, the above-mentioned bonded disk or brush can be prepared using a mixture containing lubricant capsules, binders and organic solvents, instead of the binders alone in the above-described process. In this procedure, the lubricant capsules must be made of a material that has resistance to the solvent, as well as resistance to heat. The present nonwoven abrasive materials, made according to the aforementioned process, generally have a flexural modulus of not more than 1,000 kgf / cm 2, preferably 1 to 500 kgf / cm 2, more preferably 10 to 500 kgf / cm2. The abrasive material having such basic weight range shows flexibility, so that it is easily deformed together with the working surface of the piece to be sanded or scraped. In this way, the articles of the invention allow the precise and uniform abrasive treatment of complex surfaces.

PREPARATION PROCEDURES PREPARED FABRIC PREPARATION A coarse nonwoven fabric, having a basis weight of 100 g / irr, was prepared using a 15 denier nylon, having a fiber length of 38 mm in a cloth forming machine followed by the fixation of the fiber by the use of a phenolic resin ("Shonol BRL-107" from Showa cubunshi KK of Japan). The fabric was then heated for 15 minutes at 140 ° C and cooled to a non-tacky condition, to provide a pre-bonded substrate having a basis weight of 150 g / m2.

Preparation of Lubricant Capsules 32 parts of formalin and 12 parts of urea were heated in a reaction vessel at 70 ° C for 2.5 hours. 50 parts of distilled water were added to provide a water soluble urea resin. 4290 ml of the thus obtained aqueous resin, 1420 ml of distilled water and 571 g of sodium sulfate were mixed together and heated to 90 ° C with stirring. When the temperature of the mixture reached 90 ° C, 1800 g of stearic acid were added, under constant stirring and the pH was adjusted to about 5.0. After stirring for 5 hours, the mixture was neutralized with aqueous sodium hydroxide, and the resulting lubricant capsules were separated by filtration, rinsed with distilled water and filtered a second time. The average size of the resulting capsules was 130 μm.

Preparation of metallized capsules A portion of the capsules prepared according to the preparative process described above was further coated with an aluminum, using aluminum sheet and a machine for evaporating metal (model "JEE-4X" manufactured by Nippon Denshi K.K., Japan). The aluminum was applied to the capsules to have a thickness of about 100 to 1000 angstroms. In the evaporation process, the aluminum foil was heated to a temperature of 100 ° C, under a pressure of 1-2 x 105 Torr, and the resulting aluminum vapor was deposited on a surface of the capsules in a time of 10 minutes. to 30 seconds.

Preparation of non-woven abrasive materials 100 parts of ethylene glycol monoethyl ether acetate, 150 parts of silica carbide abrasive grains of No. JIS 2000, and 80 parts of the stearic acid capsules prepared above, each based on 100 parts of resin of phenol. The resulting mixture was covered by spraying to a previously bound fabric prepared as in the previous preparative process. The substrate thus treated was cured in an oven at 160 ° C for 15 minutes, to obtain eminent, open non-woven abrasive materials, having a basic weight of 500 g / m, a thickness of 5 mm and a density of 0.12 g / cm3.

Preparation of the Unitary Disk The nonwoven abrasive materials made in accordance with the above preparative process were cut into disc shape and the discs were laminated together using a polyether urethane resin and compressed '.) under a pressure of 1 kgf / cm2 and a density of 12 sheets per inch (2"54 cm). The article was then cured in a batch oven at a temperature of 135 ° C for 4 hours to provide an abrasive article in the form of a bonded disc. The flexure modulus of the resulting disk was '- •' 200 kgf / cm :.

EXAMPLES The invention is further illustrated in the following non-limiting Examples, wherein all the parts. they are in weigh, unless specified otherwise.

EXAMPLE 1 The lubricant capsules were prepared according to the previous preparation procedure. The resulting capsules were evaluated for their solvent resistance and heat resistance, as reported later.

EXAMPLE 2 The metallized capsules were prepared according to the previous preparative procedure. The capsules were evaluated to determine their resistance to solvent and resistance to heat, as reported later.

COMPARATIVE EXAMPLE A Acrylic resin capsules from Matsumoto-Yasui Co were purchased. Ltd. From Japan, to be used as a Comparative Example. The capsules were evaluated to determine their resistance, solvent and heat resistance, as reported later.

Examples 1 and 2 and Comparative Example A The solvent resistance of the capsules of Examples 1 and 2 and Comparative Example A was tested by dipping a portion of the capsules in ethylene glycol monoethyl ether acetate). The acrylic capsules dissolved immediately, showing no resistance to the solvent. After a period of six months in the solvent, the capsules of Examples 1 and 2 were removed and examined under a microscope. Inspection of the inventive capsules indicated excellent solvent resistance. In general, these capsules did not appear to be eroded significantly by long exposure to solvent. The metallized capsules of Example 2 were evaluated as having a slightly better resistance to solvent than the capsules of Example 1. To test the heat resistance of the capsules of Examples 1 and 2, another portion of the capsules was heated to 160 °. C for 24 hours and examined at the end of the 24-hour period. Examination of these capsules revealed no damage from exposure to high temperature. Additionally, a portion of the capsules of Comparative Example A were heated to 130 ° C. These acrylic capsules melted immediately, showing no resistance to heat.

EXAMPLE 3 A disc bound according to the above preparative procedure was prepared. The disc of Example 3 was examined under the microscope to inspect the condition of the lubricant capsules contained within the disc. No change was observed in the lubricant capsules in the final product, indicating that the lubricant capsules are capable of withstanding the exposure to solvents and heat associated with the manufacture of a bonded disc.

COMPARATIVE EXAMPLE B A commercially available MG 5S-2010 disk, available from Sumitomo 3M of Japan, was selected as a control in the abrasion test described below. The disc MG 5S-2010 comprises a non-woven abrasive prepared by impregnating a non-woven fabric made of a 15 denier nylon fiber, having a length of 38 mm with a suspension comprised of abrasive grains and a phenol resin, and pressing a pile made of several sheets of the resulting fabric, having a thickness of 5 mm under a pressure of 1 kgf / cm2, by using a polyether urethane resin. Comparative Example B does not include lubricant capsules.

COMPARATIVE EXAMPLE C A disc MG 5S-2010, commercially available, was obtained as in Comparative Example B. The polishing surface of the disc was covered with a lubricating grease and the disc thus covered was used in the comparative test discussed above.

Example 3 and Comparative Examples B and C Evaluation of the abrasive ability U: 1a continuous abrasion test, was conducted for the articles of Example 3 and Comparative Examples B and C, using an abrasion machine without center (for Nisshinbo Industries, Inc., Japan) under the conditions given below. A determination of the abrasion power given. Time dependent, was made for the tested items. The cutoff amount (mg) was determined from the weight difference between pre- and post-abrasion of the steel rod used in the test, which difference is determined in the time intervals indicated in Table 1. s The conditions of the abrasion test were: VarilJja steel1 lOmm day x 150mm length Feed speed 2m / min Load 3 amp / 25 mm / 200 V Brazing time 45 sec s4 5C carbon steel (0.43 to 0.48% carbon weight) TABLE 1 Cut (mg) Time ttim 5 min 10 min 30 min 60 min 120 min 180 min Ex T 13.7 150.1 158.3 149.9 147.8 160.9 Ex. C.B 12.1 14.6 8.3 14.6 10.4 Ex .CC 5.6 18.7 12.5 10.4 As noted in the data, the disc of Example 3 was able to provide an improved initial lubricating effect, compared to the discs of the Comparative Examples and was also able to maintain its improved abrasion power as over the duration of the test procedure, without the need for additional lubricant. The discs of the Comparative Examples did not perform as well as the disc of Inventive Example 3 at any of the time intervals. The disc of Comparative B, showed a decrease in the abrasion power after the initial measurement with the leveling of the cut, being quite constant after this. The disc of Comparative Example C exhibited good initial cut, which soon decreased. (o) Evaluation of abrasion burning Using the same equipment as in the previous evaluation of the abrasive ability of the discs, the abrasion resistance of the disks of Example 3 and Comparative Ejector B was evaluated under the following conditions: Steel rod1 lOmm day x 150mm length Feed speed 0 Load 5 amp / 25 mm / 200 V Abrasion time 30 sec 1. S43C carbon steel carbon (0.43 to 0.48% coal weight) After the previous period of time, the Rod was visually inspected for abrasion burning. The steel rod used in the Comparative B test showed significant burning, while no abrasion was observed on the surface of the polished steel rod with the disc of Example 3, indicating that sufficient lubricating effect was provided by the present invention. As the results of the above test demonstrate, the lubricating capsules of the present invention clearly provide sufficient resistance to solvent and heat to resist the solvent and heat employed in the process of preparing nonwoven abrasive articles. When the. Articles of the invention are employed in abrasive applications, such as in metal finishing applications, for example, the uniform destruction of the capsules during use, provides continuous release of the lubricant and continuous lubrication without the need for additional lubricant from other sources. In addition, the abrasive articles of the invention exhibit excellent abrasion power over the length of time during which the article is used. Although a preferred embodiment of the invention has been described, it will be appreciated that changes and modifications to the embodiment described may be made by those skilled in the art, without departing from the spirit and scope of the invention, as defined in the claims. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (19)

1. An abrasive article, characterized by: a base substrate, comprising a plurality of polymeric fibers adhered to each other at contact points, the substrate having a basis weight within the range of 20 to 10,000 g / m2; abrasive grains adhered to the substrate; and a plurality of capsules comprising a continuous cover adhered to the substrate and containing lubricant therein, the cover comprises a cured thermosetting resin.

2. The abrasive article according to claim 1, characterized in that the fibers are fibers classified according to their length, having a length within the range of about 10 to 50 mm and a denier within the range of about 5 to 30.

3. The abrasive article according to claim 2, characterized in that the fibers comprise materials selected from the group consisting of polyamide, polyester, polypropylene, polyethylene, polysulfone, acrylic, polyvinyl chloride and combinations of any of the above materials.

4. The abrasive article according to claim 3, characterized in that the polyamide is nylon 6, 6.

5. The abrasive article according to claim 1, characterized in that the substrate has a void volume in the range from about 40 to 99%.

¡ß The abrasive article according to claim 1, characterized in that the abrasive grains comprise materials selected from the group consisting of silicon carbide, aluminum oxide, chromium oxide, emery and flint.

7. The abrasive article according to claim 6, characterized in that the abrasive grains have an average grain size in the range from about 0.6 to 500-0.6 μm. ?

8. The abrasive article according to claim 1, characterized in that the abrasive grains are present within the articles in an amount within the range of about 10 to 1000 parts.

5 weight per 100 parts by weight of the substrate.

9. The abrasive article according to claim 1, characterized in that the capsules comprise a thermosetting resin selected from the group consisting of epoxy resin, urea resin, melamine resin, phenol resin and polyamide resin.

10. The abrasive article according to claim 9, characterized in that the urea resin is selected from the group consisting of urea-formaldehyde resin, urea-acetaldehyde resin, urea-propionaldehyde resin and urea-butylaldehyde resin.

11. The abrasive article according to claim 9, characterized in that the melamine resin is selected from the group consisting of melamine-formaldehyde resin, melamine-acetaldehyde resin, melamine-propionaldehyde resin and melamine-butylaldehyde resin.

12. The abrasive article according to claim 9, characterized in that the phenol resin is selected from the group consisting of phenol-formaldehyde resin, phenol-acetaldehyde resin, phenol-propionaldehyde resin, phenol-butylaldehyde resin, xyleneol resin -formaldehyde, xyleneol-acetaldehyde resin, xyleneol-propionaldehyde resin and xyleneol-butylaldehyde resin.

13. The abrasive article according to claim 1, characterized in that the resin is a crosslinked urea resin comprising the reaction product of urea and a crosslinking agent in a ratio

5 molar of uiea to crosslinking agent within a range of 1: 1.2 to 1: 1.7.

14. The abrasive article according to claim 1, characterized in that the resin has a glass transition temperature id of at least about 160 ° C.

15. The abrasive article according to claim 1, characterized in that the lubricant is

5 selected from the group consisting of paraffin wax, silicone oil, polymerized olefin oil, diester oil, polyoxyalkylene glycol and halogenated hydrocarbon oil and fatty acids.

'•) I'). The abrasive article according to claim 1, characterized in that it further comprises a film surrounding the resin, the film consists of a metal or a metal oxide of nickel, copper, zinc, silver, lead or tin.

17. The abrasive article according to claim 1, characterized in that the capsules are of a size within the range of about 5 to 300 μm.

18. The abrasive article according to claim 1, characterized in that the cover has a thickness in the range from about 0.5 to 20 μm.

19. A composite abrasive article, comprising at least two layers of the non-woven abrasive article according to claim 1, characterized in that it is compressed together and adhered by a binder, the composite article has a flexural modulus of not more than 100 kgf / cm2.