WO2005082576A1

WO2005082576A1 - Non-woven fabric abrasive and manufacturing process thereof

Info

Publication number: WO2005082576A1
Application number: PCT/US2005/002296
Authority: WO
Inventors: Michihiro Yamahara
Original assignee: 3M Innovative Properties Company
Priority date: 2004-02-17
Filing date: 2005-01-25
Publication date: 2005-09-09
Also published as: JP2005230930A; JP4592300B2

Abstract

To provide a non-woven fabric abrasive manufactured with an aqueous adhesive agent precursor exerting a grinding power equal to that in a case where a solvent-type adhesive agent is used. [Means to Achieve Object] A non-woven fabric abrasive having: non-woven fabric made of fibers arranged at random; an adhesive agent adhered onto surfaces of fibers of the non-woven fabric; and abrasive grains adhered to the non-woven fabric with the adhesive agent, wherein the adhesive agent is derived from a theremosetting aqueous adhesive agent precursor containing: 100 parts by weight of an isocyanate-terminated polymer having an anionic group; 1 to 600 parts by weight of a thermosetting acrylic polymer having an hydroxyl group; and 0.01 to 100 parts by weight of a melamine-based crosslinking agent, all being dispersed uniformly in water.

Description

NON-WOVEN FABRIC ABRASIVE AND MANUFACTURING PROCESS THEREOF Field

[0001] The present disclosure relates to a non-woven fabric abrasive, and in particular a non-woven fabric abrasive for grinding materials such as metal, plastic and wood. [Background Art] [0002] Those skilled in the art have known of a non-woven fabric abrasive having: a base material such as non- woven fabric; an adhesive agent provided on a surface of the base material; and abrasive grains provided on the surface of the base material, being at least partly buried in the adhesive agent. [0003] Conventionally, in a non-woven fabric abrasive in which abrasive grains are fixed onto a non-woven fabric with an adhesive agent, a solvent-type adhesive agent precursor obtained by dissolving a binder resin into a solvent has been used mainly as an adhesive agent. This is because an aqueous adhesive agent precursor obtained by dispersing a binder resin in water is insufficient in grinding power according to an application of a non-woven abrasive. Since in a case where a solvent-type adhesive agent precursor is employed, the solvent is evaporated, however, a problem arises of giving an adverse influence on an environment and human bodies, and what's worse, another problem arises of a cost burden for recovery and reuse of the volatile solvent. [0004] In the course of manufacturing a non- woven fabric abrasive, therefore, it is desirable to use an aqueous adhesive agent precursor not causing such a problem, which has created a request for increasing a grinding power of a non- woven fabric abrasive obtained with an aqueous adliesive agent precursor to a level equal to or higher than that in a case where a solvent-type adhesive agent is used. [0005] The present disclosure is to solve the conventional problem and it is an object of the present disclosure to provide a non-woven fabric abrasive manufactured with an aqueous adhesive agent precursor exerting a grinding power equal to that in a case where a solvent-type adhesive agent is used [0006] The present disclosure provides a non-woven fabric abrasive having: non-woven fabric made of fibers arranged at random; an adhesive agent adhered onto surfaces of fibers of the non- woven fabric; and abrasive grains adhered to the non- woven fabric with the adhesive agent, wherein the adhesive agent is derived from a thermosetting aqueous adhesive agent precursor containing: 100 parts by weight of an isocyanate terminated polymer having an anionic group; 1 to 50 parts by weight of a thermosetting acrylic polymer having an hydroxyl group; and 0.01 to 20 parts by weight of a melamine-based crosslinking agent, all being dispersed uniformly in water, with which the object can be achieved. [0007] A grinding power of a non- woven fabric abrasive manufactured with an aqueous adhesive agent precursor increases to a level equal to or higher than that in a case where a solvent-type adhesive agent is used. [0008] A non- woven fabric employed in the present disclosure is a bulky sheet material made of fibers arranged at random. The non- woven fabric has only to be a material well known to those skilled in the art as a base material in a non-woven fabric abrasive. Typical non- woven fabrics are described, for example, in a passage from column 10, line 10 to column 11, line 25 of Japanese Patent Publication No. H3(1991)-55270. [0009] Examples of preferable non-woven fabrics include: those made of thermoplastic organic fibers with thermoplastics such as polyamide (for example, Nylon 6 and Nylon 6, 6 made of polycaprolactam and polyhexamethyladipamide, respectively), polyolefin (for example, polyprolylene and polyethylene), polyester (for example, polyethylene terephthalate) and polycarbonate. Generally, non- woven fabrics made of fibers of Nylon or polyester have been used. Thickness values of fibers are generally on the order in the range of from 19 to 250 μm. A thickness of a non- woven fabric is generally on the order in the range of from 2 to 50 mm. [0010] An adhesive agent is a material coupling a non- woven fabric and abrasive grains together. An adhesive agent has only to be a material having a strength enough to sustain bonds between a non-woven fabric and abrasive grains during grinding. An adliesive agent generally includes a binder resin and an additive material, if necessary, as components. A binder resin is an organic resin exerting a function to couple materials together by alteration from an adhesive liquid to a stiff solid. An adhesive agent precursor is used for referring especially to a coatable fluid composition including an uncured binder resin, an additive material and a solvent, if necessary. [0011] An aqueous adhesive agent precursor is employed in the present disclosure. An aqueous adhesive agent precursor is an adhesive agent precursor including water mainly as a solvent. An aqueous adhesive agent precursor generally takes a state where a binder resin is uniformly dispersed in water, which is referred to as an emulsion or a suspension. A resin capable of being uniformly dispersed in water is referred to as a water-dispersible resin. [0012] An uncured binder resin is preferably required to be water-dispersible and thermosettable. This is because that it is easy to obtain a non-woven fabric abrasive by shaping. It is preferable that a binder resin has a curing temperature in the range of from 100 to 300°C and especially in the range of from 100 to 200°C. If a curing temperature of a binder resin is lower than 100°C, curing may become insufficient, abrasive grains become easy to drop, and grinding ratio becomes poor. On the other hand, if a curing temperature thereof exceeds 300°C, the binder resin may be decomposed, abrasive grains become easy to drop, and grinding ratio becomes poor. It is preferable that a binder resin after curing has a tensile strength in the range of from 3000 to 11000 psi; an elongation of 180% or more and especially in the range of from 180 to 800%; and a Shore D hardness of 40 or higher and especially in the range of from 40 to 80. If a tensile strength of a binder resin after curing is less than 3000 psi, a strength and a stiffness of an adhesive agent after the curing is too low to suit a non- woven fabric abrasive, while if exceeding 11000 psi, a strength and a stiffness of an adhesive agent after the curing is too high to suit the non-woven fabric abrasive. If an elongation of a binder resin after curing is less than 180%, a flexibility of an adhesive agent after the curing is too low to suit a non- woven fabric abrasive, while if exceeding 800%, a flexibility of an adhesive agent after the curing is too high to suit a non-woven fabric abrasive. If a Shore D hardness of a binder resin after curing is lower than 40, abrasive grains are easy to fall off from a non- woven fabric abrasive during grinding, while if exceeding 80, a self-renewal of a non- woven fabric becomes insufficient. [0013] An uncured binder resin preferably shows no tackiness even if being touched with a finger or the like in an environment at room temperature. This is because it is easy to handle an abrasive intermediate obtained by coating an adhesive agent precursor on an non-woven fabric to then dry the adhesive agent thereon. [0014] A preferable binder resin is a thermosetting resin, including an isocyanate-terminated polymer having an anionic group, a thermosetting acrylic polymer having a hydroxyl group and a melamine-based crosslinking agent, and showing water-dispersibility. A combination of an isocyanate polymer, which is a soft segment, and an acrylic polymer, which is a hard segment, can adjust characteristics of a binder resin optimally in order to adhere abrasive grains to a non-woven fabric. [0015] As a result, an aqueous adhesive agent precursor employed in the present disclosure has a strength for holding abrasive grains equal to or higher than that of a solvent-type adhesive agent precursor to thereby prevent the abrasive grains to fall off from a non-woven fabric and enable the non- woven fabric to be provided with a proper self-renewal function so as to enable grinding with a fresh grinding surface to be effected at all times. [0016] An isocyanate-terminated polymer having an anionic group, a thermosetting acrylic polymer having a hydroxyl group and a melamine-based crosslinking agent may be each mixed together in a state of an emulsion or a water-dispersion. [0017] Employed is an isocyanate-terminated polymer having an anionic group in a molecule thereof alone or a mixture of an isocyanate-terminated polymer having no anionic group and an isocyanate-terminated polymer having an anionic group in a molecule thereof, and it is preferable to use a resin component (a mixture of an isocyanate-terminated polymer having an anionic group in a molecule thereof and an isocyanate-terminated having no anionic group in a molecule thereof) having an anionic group in the range of from 0.001 to 0.5 equivalent relative to 100 g of the total amount the resin, which the resin component is good in water-dispersibility to thereby enable a water-dispersion thereof to be obtained without using an emulsifier or a dispersing agent. Exemplified as the anionic group are a carboxyl group, a sulfone group and a combination thereof, among which a carboxylic group is preferable. [0018] The isocyanate-terminated polymer having an anionic group in a molecule thereof can be obtained by means of a conventionally known method and in a case of introduction of carboxyl group as an example, the polymer can be obtained through a reaction of^" a polyisocyanate with a polyetherpolyol and/or a polyester polyol, as a polyol component, having a diol unit including a carboxyl group such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutric acid, 2,2-dimethylolvaleric acid or the like. [0019] A polyol component of polyetherpolyol and/or polyesterpolyol used in obtaining an isocyanate-terminated polymer having an anionic group in a molecule thereof and an isocyanate-terminated polymer having no anionic group in a molecule thereof is desirably of an average molecular weight in the range of from 500 to 4000, wherein a polyisocyanate component is not specifically limited and examples thereof include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate and the like; alicyclic polycyanates such as 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexyl diisocyanate and the like; and aromatic polyisocyantes such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and the like, among which an aliphatic or alicyclic polyisocyanate is preferable. [0020] An isocyanate-terminated polymer described above may also be an isocyante-terminated polymer chain-extended with dialkyl amine, dialkyl hydrazide or the like, any of which can be optionally selected according to an application in the range as far as a water-dispersion can be obtain. Water-dispersions of an isocyanate-terminated polymer having an anionic group in a molecule thereof are sold on the market, examples of which include the polymers of "BONTIGHTER" type, manufactured by Asahi Denka Co., Ltd., product Nos. HUX-232, HUX-240, HUX-260, HUX-320, HUX-350, HUX-380, HUX-381, HUX-380A, HUX-386, HUX-401, HUX-670, HUX-290H, HUX-290N, HUX-394, HUX-680 and the like. [0021] A thermosetting acrylic polymer having a hydroxyl group is preferably an acrylic polymer emulsion obtained by uniformly dispersing in water. The acrylic polymer has a hydroxyl value in the range of from 40 to 100. If the hydroxyl group is less than 40, the number of reaction sites is small to thereby cause a reaction insufficiently, disabling the object of the present disclosure to be achieved. On the other hand, if the hydroxyl value exceeds 100, water-proofness of an adhesive agent after curing is reduced. The acrylic polymer has an acid value in the range of from 1 to 30. If the acid value is less than 1, a stable emulsion is hard to be obtained, while if exceeding 30, a hydrophilicity of a polymer is enhanced; therefore, an emulsion becomes of a high viscosity and a water-proofhess of an adhesive agent is reduced. The acrylic polymer has a glass transition temperature in the range of from -40 to 10°C. If the glass transition temperature is lower than -40°C, an adhesive agent has faults in physical strength and durability, while if higher than 10°C, a hardness of an adhesive agent increases and a flexibility thereof in low temperature is reduced. [0022] An acrylic polymer emulsion is prepared from unsaturated monomers as described below: 1. Examples of acrylic-based monomers each having a hydroxyl group include ethylenic unsaturated monomers each having a hydroxyl group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, lactone-modified 2-hydroxyethyl acrylate, and lactone-modified 2-hydroxyethyl methacrylate. 2. Examples of alkyl esters of acrylic acid or methacrylic acid include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate and the like. 3. Examples of α,β-ethylenic unsaturated carboxyl acids include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, fumalic acid and the like. 4. Examples of vinyl aromatic compounds include styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine and the like. 5. Examples of other vinyl compounds include ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, divinylbenzene, trimethylolpropane triacrylate and the like. [0023] The unsaturated monomers can be used in mixtures of an acrylic monomer including a hydroxyl group and an ,β-ethylenic unsaturated carboxyl acid monomer as indispensable components; and if necessary, an alkyl ester of acrylic acid or methacrylic acid and other vinyl compounds; and the like, wherein kinds and a mixing ratio of each can be properly selected according to a desired physical property of a resin. [0024] Preferable examples of chain transfer agents for adjusting a molecular weight include methyl mercaptan, ethyl mercaptan, isopropyl mercaptan, butyl mercaptan, pentyl mercaptan, hexyl mercaptan, octyl mercaptan, decyl mercaptan, undecyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan and the like. [0025] Production of a copolymer included in an acrylic polymer emulsion of the present disclosure is performed according to a known method and can be realized with, for example, a solution polymerization method, an emulsion polymerization method or a suspension polymerization method, among which the emulsion polymerization method is preferable. The polymerization generally goes this way, in which monomers are three-dimensionally crosslinked in the presence of a dispersion stabilizer such as a surfactant and a polymerization initiator, for example a radical initiator for a radical polymerization such as ammonium persulfate or the like, at a reaction temperature, preferably, in the range of from 60 to 95°C for a time, preferably in the range of from 4 to 8 hr, and then, the reaction mixture is neutralized with an amine, thereby enabling a target acrylic polymer emulsion to be obtained. Diameters of fine particles in the obtained acrylic polymer emulsion are preferably in the range of from 50 to 200 nm. Such a microemulsion is on the market and examples thereof include "Hitaloid type" manufactured by Hitachi Chemical Co., Ltd., product No. AE8200 and like. [0026] Melamine-based crosslinking agents have only to be known melamine-based crosslinking agents as a crosslinking agent for synthetic resin. The agents can be dispersed in water either with an emulsifying agent or a dispersing agent, if necessary, or without them. A melamine-based crosslinking agent is not specifically limited and exemplified are "Melan 5100" manufactured by Hitachi Chemical Co., Ltd. and the like. [0027] Mixing proportions of components of a thermosetting aqueous adhesive agent precursor are generally 100 parts by weight of an isocyanate-terminated polymer having an anionic group; 1 to 600 parts by weight of a thermosetting acrylic polymer having an hydroxyl group; and 0.01 to 100 parts by weight of a melamine-based crosslinking agent. If an amount of a thermosetting acrylic polymer having a hydroxyl group is less than 1 part by weight, a flexibility of an adhesive agent after curing is excessively high by the action of a characteristic of an isocyanate-terminated polymer having an anionic group so as not to suit a non- woven fabric abrasive, while if exceeding 600 parts by weight, a flexibility of an adhesive agent after curing is excessively low so as not suit a non- woven fabric abrasive. If an amount of a melamine-based crosslinking agent is less than 0.01 part by weight, a flexibility of an adhesive agent after curing is excessively high so as not to suit a non-woven fabric abrasive, while exceeding 100 parts by weight, a flexibility after curing is excessively small so as not to suit a non- woven fabric abrasive. When a brush form of abrasive is manufactured, a tackifying agent such as a terpene-resin maybe included, thereby interlayer strength of the brush is increased to improve durability of the brush. As the fine particles of the acrylic polymer emulsion, those having a particle size of 0.01 to 200 mm maybe employed. [0028] Abrasive grains employed in the present disclosure are types commonly used in this business world. Typically, it is only required that abrasive grains are particles having an average diameter in the range of from 4 to 2000 μm and preferably in the range of from 20 to 1000 μm; and a Mohs hardness in the range of from 4 to 10 Mohs and preferably in the range of from 6 to 9 Mohs. To be concrete, examples of particles used include particles made of pumice, topaz, garnet, alumina, corundum, silicon carbide, zirconia, diamond and the like. The particles may be either a mixture of different sizes or a mixture of different kinds of materials. [0029] A non- woven fabric abrasive of the present disclosure can be manufactured in conformity with a method known to those skilled in the art. For example, a process goes this way: a binder resin is dispersed in water or each component of a binder resin dispersed in water is mixed together to prepare an aqueous adhesive agent precursor. The adhesive agent precursor is coated on surfaces of fibers in a non- woven fabric. Abrasive grains are scattered on and attached to the coated adhesive agent precursor. Thereafter, water is evaporated from the adhesive agent precursor to dry it. In a case where a thermosetting resin is used as a binder resin, the adhesive agent precursor is heated for a predetermined time to be cured. Generally, the adhesive agent precursor is mentioned at 100 to 300°C for 10 to 30 min to thereby be cured. [0030] Abrasive grains are added into an adhesive agent precursor in advance when the precursor is prepared, and the adhesive agent precursor and the abrasive grains in thus prepared mixture may also be simultaneously applied to a non-woven fabric. Furthermore, drying of the adhesive agent precursor and curing of the thennosetting resin may be effected either in the same heating step or in different heating steps. Even in a case where the drying of the adhesive agent precursor and the curing of the thermosetting resin are implemented in different steps, the thermosetting resin can be partly cured in the drying step without causing any trouble. [0031] As described above, a non-woven fabric used as a base material is a bulky fibrous material and excellent in elasticity; therefore, easy deformation and restoration can be secured. Therefore, a laminate including plural non-woven fabric layers is easy in deformation and can be shaped with a relative freedom under a pressure. In a preferred embodiment of the present disclosure, a non- woven fabric abrasive of a three-dimensional shape is manufactured with the help of a easy shapability of the non- woven fabric. A typical example of a non- woven fabric abrasive of a three-dimensional shape is a cylindrical grinding brush having a center hole. Figs. 1(a) to 1(c) are perspective views showing typical structure types of cylindrical grinding brushes each having a center hole. Fig. 1(a) shows a view of a laminate type, Fig. 1(b) a flap type and Fig. 1(c) a spiral type. [0032] Fig. 2 is a model representation showing a process of manufacturing an abrasive intermediate used in manufacturing a non- woven fabric abrasive of a three-dimensional shape. At first, a non-woven fabric 10 is sent out from a roll 100 of a non- woven fabric. Then, the non- woven fabric 10 is impregnated with a mixture of an adhesive agent precursor and abrasive grains. The impregnated non- woven fabric is heated to fix a thermosetting resin and the abrasive grains on surfaces of fibers of the non- woven fabric. The adhesive agent precursor is spray-coated on the surface thereof. [0033] Then, water is evaporated from the adhesive agent precursor to dry it in a drying furnace. The drying is conducted at a temperature for a time in the combination of which the thermosetting resin is not perfectly cured so that the adhesive agent precursor is of non-tackiness at room temperature. This is because if the adhesive agent precursor still sustains a tackiness at room temperature after the drying step, it becomes difficult to handle and work the obtained abrasive intermediate and because if the thermosetting resin is perfectly cured after the drying step, it becomes difficult to shape the abrasive intermediate thereafter. In a preferable embodiment of the present disclosure, the drying step is conducted at a temperature in the range of from 100 to 120°C for a time in the range of from 1 to 10 min. After the drying step, the obtained abrasive intermediate 20 loses a tackiness and thereby can be handled. Therefore, the abrasive intermediate 20 can be taken up and stored as a roll 200. [0034] Fig. 3 is a model representation showing a process of manufacturing a non- woven fabric abrasive of a three-dimensional shape using an abrasive intermediate. At first, the abrasive intermediate 20 is sent out from the roll 200 of the abrasive intermediate. Then, the abrasive intermediate 20 is punched therethrough into proper shapes to obtain intermediate members 25. Jigs 6, 7 and 8 are used to superimpose plural intermediate members 25 one on another and the superimposed intermediate members 25 are compressed to a high density. Thereafter, the intermediate members 25 are heated in a compressed state to completely cure the adhesive agent precursor and to thereby fix a shape thereof. In the preferred embodiment, the heat curing step is conducted at a temperature in the range of from 100 to 200°C for a time in the range of from 10 to 60 min. In such a heat curing step, a cylindrical grinding brush having a center hole can be obtained (see Fig. 1(a)). [0035] In a manufacturing process of a non- woven fabric abrasive of the present disclosure, an aqueous adhesive agent precursor is employed, so an evaporating material is water, neither which exerts an adverse influence on an environment and human bodies nor which requires recovery of a volatile material. Furthermore, water has a boiling point lower than a solvent generally employed in a solvent-type adhesive agent, making energy for drying smaller. [0036] While detailed description will be given of the present disclosure showing the following examples, the present disclosure is not limited thereto. Unless otherwise explicitly specified in the examples, "part or parts" are an amount by weight. [0037] Table 1

In the table, mixing proportions are relative to the weight of a solid resin. [0038] Each component was mixed in mixing proportions shown in Table 1 to prepare adhesive agent precursors. The adhesive agent precursors were coated on both surfaces of each of non- woven fabrics as shown in Table 2. A dry coating amount of the adhesive agent precursor thereon was 400 g/m². [0039] Table 2 Material and size of the non- woven fabric

[0040] Silicon carbide abrasive grains of 500 μm in average diameter (manufactured by 3M Co.) were uniformly scattered and attached onto the coated adhesive agent precursor using a scattering method. A coating amount of the abrasive grains was 2300 g/m². Thereafter, the non-woven fabrics with the adhesive agent precursor and abrasive grains thereon were placed into an oven and heated at 110°C for 10 min to dry the adhesive agent precursor. By having done so, obtained were abrasive intermediate sheets without a tackiness and therefore, capable of being handled. [0041] Each of the abrasive intermediate sheets were punched therethrough to prepare 2 pieces of abrasive intermediate disks of 10 cm in diameter. The abrasive intermediate disks were superimposed one another to form a laminate and the laminate was compressed to a thickness of 10 mm. The compressed laminates were placed in an oven and heated at a temperature of 150°C for 30 min to completely cure the adhesive agent precursor. [0042] The obtained non- woven fabric abrasives are grinding wheels each of 10 cm in diameter and 10 mm in thickness. Grinding was conducted by pressing a non- woven fabric abrasive with a load of 2kg against a side surface of an iron plate (SPCC-SB) as a grinding work piece while being rotated. Grinding conditions were a griding speed of 10000 rpm and grinding times of 30 min, 60 min and 90 min. [0043] Each of measurements in grinding was conducted on a change in weight of a non- woven fabric abrasive (g) and a change in weight of a grinding work piece (g) before and after grinding to calculate a grinding ratio (a change in weight of a grinding work piece/a change in weight of a non-woven fabric abrasive). The results are shown in Table 3. [0044] Table 3

[0045] A change in weight of a non- woven fabric abrasive shows an amount of abrasive grains falling off from the non- woven fabric abrasive. A non- woven fabric abrasive of the present disclosure employing an aqueous adhesive agent precursor was small in amount of falling-off particles and shows a grinding ratio equal to or higher than a non-woven fabric abrasive using a solvent type adhesive agent precursor. [0046] Such an improvement on a non-woven fabric abrasive in characteristic has been recognized in not only a grinding disk of a laminate type described above but also grinding brushes of a spiral type and a flap type and others. Brief Description of the Drawing

[0047] Figs. 1(a) to 1(c) are perspective views showing cylindrical grinding brushes of typical structure types each having a central hole. Fig.2 is a model representation showing a process of obtaining an abrasive intennediate used in manufacturing a non- woven fabric abrasive of a three-dimensional shape. Fig. 3 is a model representation showing a process of manufacturing a non- woven fabric abrasive of a three-dimensional shape using an abrasive intermediate.

Claims

CLAIMS: [Claim 1] A non- woven fabric abrasive having: a non- woven fabric made of fibers arranged at random; an adhesive agent adhered onto surfaces of fibers of the non- woven fabric; and abrasive grains adhered to the non-woven fabric with the adhesive agent, wherein the adhesive agent is derived from a thermosetting aqueous adhesive agent precursor containing: 100 parts by weight of an isocyanate terminated polymer having an anionic group; 1 to 600 parts by weight of a thermosetting acrylic polymer having an hydroxyl group; and 0.01 to 100 parts by weight of a melamine-based crosslinking agent, all being dispersed uniformly in water. [Claim 2] A non- woven fabric abrasive according to claim 1, wherein the aqueous adhesive agent precursor further includes from 0.01 to 2.0 parts by weight of a terpene resin. [Claim 3] A non- woven fabric abrasive according to claim 1 or 2, wherein the thermosetting acrylic polymer having an hydroxyl group has a hydroxyl value in the range of from 40 to 100, an acid value of from 1 to 30, a glass transition temperature in the range of from -40 to 10°C, and particle diameters in the range of from 70 to 80 nm. [Claim 4] A non-woven fabric abrasive according to claim 1 or 2, wherein the adhesive agent precursor has a curing temperature in the range of from 100 to 300°C, a tensile strength after curing in the range of from 3000 to 11000 psi, an elongation in the range of from 180 to 800% and a Shore D hardness in the range of from 40 to 80. [Claim 5] A manufacturing process of a non-woven fabric abrasive comprising the steps of: coating a theremosetting aqueous adhesive agent precursor containing: 100 parts by weight of an isocyanate terminated polymer having an anionic group; 1 to 50 parts by weight of a thermosetting acrylic polymer having an hydroxyl group; and from 0.01 to 20 parts by weight of a melamine-based crosslinking agent, all being dispersed uniformly in water; and abrasive grains on surfaces of fibers of a non- woven fabric made of fibers arranged at random; drying the adhesive agent precursor to obtain an abrasive intermediate of a non-tackiness; shaping the abrasive intermediate; and heating the shaped abrasive intermediate to cure the thermosetting resin.