MXPA02006160A - Abrasive material having abrasive layer of threedimensional structure. - Google Patents

Abstract

To provide an abrasive material which is excellent in loading resistance and durability, allows no attachments to attach to an abraded surface even when the end surface of the optical fiber is abraded, and is particularly suited for use in abrading a hard material such as an end surface of an optical fiber connector effectively and smoothly into a predetermined shape. The present invention provides an abrasive material for abrading an end surface of an optical fiber connector into a predetermined shape, the abrasive material having a base material (101) and an abrasive layer (102) disposed on the base material, the abrasive layer having a top layer (105) comprising an abrasive composite containing abrasive grains and a binder and a foot portion (106) comprising a binder in the absence of abrasive particles, the abrasive layer having a threedimensional structure constructed with a plurality of regularly arranged threedimensional elements (104) having a predetermined shape. Further, the present invention provides a method for producing an abrasive material having an abrasive layer of a threedimensional structure, the method comprising the steps of: (1) filling a mold sheet having a plurality of regularly arranged recesses, with an abrasive material coating solution containing abrasive grains, a binder, a solvent, to a predetermined depth; (2) removing the solvent from the abrasive material coating solution in the recesses by evaporation; (3) filling the recesses further with a binder; (4) laminating a base material on the mold sheet to bond the binder to the base material; and (5) hardening the binder.

Description

ABRASIVE MATERIAL WHICH HAS AN ABRASIVE LAYER OF THREE-DIMENSIONAL STRUCTURE FIELD OF THE INVENTION The present invention relates to an abrasive material having an abrasive layer of a three-dimensional structure, and more particularly to an abrasive material having an abrasive layer of a three-dimensional structure and which is suitable for abrading an end surface of an optical fiber on the which assembles a splice sleeve, ie, an end surface of a fiber optic connector, in order to give it a predetermined shape.

BACKGROUND OF THE INVENTION Conventionally an optical fiber connector that can be easily removed, it is widely used for the connection of optical fibers in a fiber optic communications network. In the connection in the fiber optic connector, the end surfaces of the fiber optic splice sleeves, made of an optical fiber, and a splice portion (splice sleeve) to cover the optical fiber, are allowed to directly connect between REF .: 139563 yes. Therefore, the optical characteristics at the moment of making the connection, particularly the loss of connection, depend on the processing properties and the precision of the extreme surfaces of the optical fibers. The end surface of the fiber optic splice sleeve is processed through a number of abrasion steps. The quality of the end surface is influenced by the processing properties and the precision in the final finishing abrasion stage. In other words, the main factors for the loss of connection of the optical fiber are the degree of roughness of finish, of the extreme surface, and its inclination. With respect to the roughness of the finish, of an end surface of a fiber optic splice sleeve, the correlation with the particle size of an abrasive material used for the fiber is reported. abrasion. For example, in the case of a fiber of the index type in step, the connection loss is approximately 0.5 dB if the particle size of the abrasive grains is approximately 1um, while the loss of connection is greater than approximately 1.0. dB if the particle size of the abrasive grains is approximately 15. um. By observing this correlation it will be understood that abrasive grains having a particle size of 10 to 15 μP should be used? in order to satisfy a standard that requires a loss of fiber optic connection less than 1 dB, and fine grade abrasive grains having a particle size less than 1 μp? they must be used in order to satisfy a standard that requires a loss of fiber optic connection of less than 0.5 dB. Japanese Patent Laid-Open Publication No. 09-248771 / 1997 discloses an abrasive belt for an end surface of a fiber optic connector, in which the abrasive belt has a base material and an abrasive layer placed on the base material, the layer abrasive is composed of silica particles having an average particle size of 5 to 30 μp \ and has a binder to connect these particles of abrasive material, and the average roughness of the center line Ra of the surface of the abrasive layer is 0.005 to 0.2 μp ?. Fine grade abrasive materials, such as an abrasive belt for an end surface of a fiber optic connector, have the problem of loading. The term "loading" means that the space between the abrasive grains is filled with abrasion powders, which protrude to inhibit the abrasive property. For example, in the case where an end surface of an optical fiber connector is subjected to abrasion, the particles of the abrasion powders remain in the space between the abrasive grains, and therefore the cutting capacity of the abrasive particles. the abrasive grains decreases. In addition, the liquid that is used as a refrigerant and a lubricant, does not act sufficiently between the abrasive material and the end surface of the fiber optic connector, whereby a part of the abrasive layer adheres to the surface of the fiber optic connector after abrasion, and its removal is problematic. In addition, if fine particles are used as abrasive grains, the time required for abrasion will be long. On the other hand, if the particle size of the abrasive grains increases, the finished end surface of the fiber optic connector will be rough, failing then to satisfy the standard of loss of fiber optic connection. If both methods are used in combination, the number of abrasion stages will be increased. WO92 / 13680 and W096 / 27189 describe an abrasive material having an abrasive layer of a three-dimensional structure. This abrasive material has a base material and an abrasive material placed on the base material, the abrasive layer is made of an abrasive composite material containing abrasive particles and a binder, and the abrasive layer has a three-dimensional structure constructed with a plurality of three-dimensional elements arranged on a regular basis, they have a default form. As the shape of the three-dimensional elements, the tetrahedral shape, the pyramidal shape and others are described. This abrasive material is load resistant and of excellent durability. However, since the abrasive grains are uniformly dispersed throughout the abrasive layer, and the abrasive grains are located on the bottom of the abrasive layer, they do not effectively act as the production cost is high. In addition, an abrasive material having that abrasive layer of a three-dimensional structure is produced by applying a liquid abrasive paste containing abrasive particles and a binder in a molding sheet having a structure, overlaying a base material on the molding sheet to join the binder to the base material, harden the binder by ultraviolet radiation, and remove the molding sheet. In this case, the abrasive liquid paste must have sufficient fluidity to be introduced into the structure within the molding sheet. Furthermore, since ultraviolet radiation is applied after covering the liquid abrasive paste with the base material, the liquid abrasive paste must not contain a volatile component. Therefore, the content of the abrasive grains in the abrasive liquid paste can not exceed the critical volumetric concentration of pigment. Accordingly, the conventional abrasive material having an abrasive layer of a three-dimensional structure, has the problem that the content of abrasive grains in the abrasive layer can not rise sufficiently. By making a comparison under abrasive conditions in which the particle size of the abrasive grains, the abrasive medium, and others are the same, the abrasive property of the abrasive material will decrease as the content of the abrasive grains is reduced. Particularly, in fine grade abrasive materials, the abrasive efficiency will be poor to increase the period of time required for abrasion, if the content of abrasive grains is insufficient. Accordingly, since the content of the abrasive grains is insufficient, the conventional abrasive material, which has an abrasive layer of a three-dimensional structure, has a poor abrasive property and is therefore not suitable for abrading a hard material such as a surface end of a fiber optic connector, efficiently and uniformly, to produce a predetermined shape. The present invention has been made to solve the aforementioned problems existing in the prior art, and an object thereof is providing an abrasive material having excellent load resistance and durability, which does not allow joints to a worn surface, even when the end surface of the optical fiber is worn, and which is particularly suitable for use in abrading a hard material such as an end surface of an optical fiber connector, effectively and uniformly, to produce a predetermined shape.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides an abrasive material for abrading an end surface of an optical fiber connector and producing a predetermined shape, the abrasive material having a base material and an abrasive layer placed on the base material, the three-dimensional elements having (1) a layer top comprising an abrasive composite material containing abrasive grains dispersed in a binder and (2) a base portion comprising a binder in the absence of abrasive particles, the abrasive layer having a three-dimensional structure constructed with a plurality of three-dimensional elements arranged in regular form, having a predetermined shape, to thereby achieve the object of the present invention mentioned above.

In addition, the present invention provides a method for producing an abrasive material having an abrasive layer of a three-dimensional structure, the method comprising the steps of: (1) filling a sheet mold having a plurality of cavities disposed in a regular manner, with a coating solution of abrasive material, containing abrasive grains, a binder, and a solvent, to a predetermined depth; (2) remove the solvent from the coating solution of abrasive material, in the cavities, by evaporation; (3) filling the cavities additionally with a binder, in the absence of abrasive particles; (4) laminating a base material on the sheet mold, to join the binder to the base material; and (5) hardening the binder. The abrasive material having an abrasive layer of a three-dimensional structure is preferably produced by the aforementioned production method.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and features, as well as additional objects and features of the invention, will be more fully apparent, from the following detailed description, together with the drawings annexes, in which, Figure 1 is a sectional view illustrating an abrasive material having an abrasive layer of a three-dimensional structure in accordance with an embodiment of the present invention; Figure 2 is a plan view illustrating an abrasive material having an abrasive layer of a three-dimensional structure in accordance with an embodiment of the present invention; Figure 3 is a plan view illustrating an abrasive material having an abrasive layer of a three-dimensional structure in accordance with an embodiment of the present invention; Figure 4 is a sectional view, in perspective, illustrating an abrasive material having an abrasive layer of a three-dimensional structure in accordance with an embodiment of the present invention; Figure 5 is a plan view illustrating a material having an abrasive layer of a three-dimensional structure in accordance with an embodiment of the present invention; Figures 6 (a) to 6 (e) are model views illustrating steps for producing an abrasive material having an abrasive layer of a three-dimensional structure; Figure 7 is a graph showing the change with respect to time, of a weathered quantity, when an end surface of a fiber optic connector is subjected to abrasion with various abrasive materials; Figure 8 is a microscope photograph of an end surface of a fiber optic connector after being subjected to abrasion with the abrasive material of the present invention; Figure 9 is a microscope photograph of an end surface of an optical fiber connector after being subjected to abrasion with the abrasive material of the present invention; Figure 10 is a microscope photograph of an end surface of a fiber optic connector after being subjected to abrasion with the abrasive material of the prior art; Figure 11 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the prior art; Figure 12 is a microscope photograph of an end surface of a fiber optic connector after being subjected to abrasion with the abrasive material of the prior art; Figure 13 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 14 is a microscope photograph of an end surface of a fiber optic connector after being subjected to abrasion with the abrasive material of the present invention; Figure 15 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the prior art; Figure 16 is a graph showing the change with respect to time, of a weathered quantity when a circular zirconia rod is subjected to abrasion with various abrasive materials; Figure 17 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 18 is a microscope photograph of an end surface of an optical fiber connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 19 is a microscope photograph of an end surface of a fiber optic connector after being subjected to abrasion with the abrasive material of the present invention; Figure 20 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 21 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the prior art; Figure 22 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the prior art; Figure 23 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 24 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; Figure 25 is a microscope photograph of an end surface of a fiber optic connector, after being subjected to abrasion with the abrasive material of the present invention; DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a sectional view illustrating an abrasive material having an abrasive layer of a three-dimensional structure, as an embodiment of the present invention. An abrasive material 100 has a base material 101 and an abrasive layer 102 placed on a surface of the base material 101. Preferred examples of the base material for the present invention include polymeric film, paper, cloth, metal film, vulcanized fiber, nonwoven base material , a combination thereof, and a processed product thereof. In the case of subjecting the end surface of the fiber optic connector to spherical abrasion, the base material is preferably flexible, whereby the formation of a spherical shape is facilitated. The base material is preferably transparent with respect to ultraviolet radiation, since it is convenient in the production process. The base material can be, for example, a polymer film such as polyester film. The polymeric film may have a lower coating of a material such as polyethylene acrylic acid, in order to promote the bonding of the base material of the abrasive compound. The abrasive layer 102 has an abrasive compound containing a matrix of a binder and abrasive grains 103 dispersed therein, as building components. The abrasive compound is formed from a liquid paste containing a plurality of abrasive grains dispersed in the binder which is in an uncured or uncoagulated state. Upon hardening or coagulation, the abrasive compound solidifies, ie is fixed to have a predetermined shape and a predetermined structure. The size of the abrasive grains can vary depending on the type of the abrasive grains or the intended use of the abrasive material. For example, the dimension is from 0.01 to 1 μm, preferably from 0.01 to 0.5 μm, more preferably from 0.01 to 0.1 μm for the final finishing abrasion, and is from 0.5 to 20 μp, preferably from 0.5 to 10 μp? for rough abrasion in the formation of a curved surface. Preferred examples of the abrasive grains for the present invention include diamond, cubic boron nitride, cerium oxide, fused aluminum oxide, heat-treated aluminum oxide, sol-gel aluminum oxide, silicon carbide, chromium oxide, silica , zirconia, alumina zirconia, iron oxide, garnet, and a mixture of them. Especially preferred are diamond, cubic boron nitride, aluminum oxide and silicon carbide, for rough abrasion, and silica and aluminum oxide for finishing abrasion. The binder hardens or coagulates to form an abrasive layer. Preferred examples of the binder include phenolic resin, phenolic resole resin, aminoplast resin, urethane resin, epoxy resin, acrylate resin, polyester resin, vinyl resin, melamine resin, acrylated isocyanurate resin, urea-formaldehyde resin, resin of isocyanurate, acrylated urethane resin, acrylated epoxy resin, and a mixture thereof. The binder can be a thermoplastic resin. Particularly preferred examples of the binder include the phenolic resin, the phenolic resole resin, the epoxy resin, and the urethane resin. The binder can be cured by radiation. The binder that is cured by radiation is a binder that at least partially hardens or that is at least partially polymerized by radiation energy. Depending on the binder that is used, an energy source such as heat, infrared radiation, electron beam radiation, ultraviolet radiation, or a visible light radiation. Typically these binders are polymerized through a free radical mechanism. Preferably these binders are selected from the group consisting of acrylated urethane, acrylated epoxy, an aminoplast derivative having an unsaturated carbonyl group, β, an ethylenic unsaturated compound, an isocyanurate derivative having at least one acrylate group, an isocyanate having at least one acrylate group, and a mixture thereof . If the binder is hardened by ultraviolet radiation, a photoinitiator is required to initiate free radical polymerization. Preferred examples of the photoinitiator, to be used for this purpose, include organic peroxides, azo compounds, quinones, benzophenones, nitroso compounds, halides, acrylics, hydrazones, mercapto compounds, pyrylium compounds, triacrylimidazole, bisimidazole, chloroalkyltriazine, bezoin ether, benzyl ketal, thioxanthone, and acetophenone derivatives. A preferred photoinitiator is 2, 2-dimethoxy-1,2-diphenyl-1-ethanone. If the binder is hardened by visible light radiation, it is necessary for a photoinitiator to initiate a free radical polymerization. Preferred examples of the photoinitiator for this purpose are described in United States Patent No. 4,735,632, column 3, line 25 to column 4, line 10, column 5, lines 1 to 7, and column 6 lines 1 to 35, which is incorporated herein by reference . The weight ratio of the abrasive grains to the binder is typically within a range of about 1.5 to 10 parts of abrasive grains with respect to a portion of the binder, preferably from about 2 to 7 parts by weight of abrasive grains. with respect to a part of the binder. This proportion can vary depending on the size of the abrasive grains, depending on the type of binder used and the intended purpose for the abrasive material. In the uniform and fine abrasion, a hard material such as an end surface of a fiber optic connector, the concentration of the abrasive grains, contained in the abrasive compound, is preferably within a range of 43 to 90% by weight, if the abrasive grains are composed of silicon carbide; from 70 to 90% by weight if the abrasive grains are composed of spherical abrasive particles of alumina, silica or the like; from 37 to 90% by weight if the abrasive grains are composed of alumina; and from 39 to 90% by weight if the abrasive grains are composed of diamond. The abrasive compound may contain a material different from abrasive grains and binder. For example, the abrasive material may contain ordinary additives such as a coupling agent, a lubricant, a dye, a pigment, a plasticizer, a filler, a scrubbing agent, an abrasive aid, and a mixture thereof. The abrasive compound may contain a coupling agent. The addition of the coupling agent can considerably reduce the coverage viscosity of a liquid paste that is used for the formation of the abrasive compound. Preferred examples of the coupling agent for the present invention include, organic xylan, zircoaluminate, and titanate. The amount of the coupling agent is typically less than 5% by weight, preferably less than 1% by weight, of the binder. The abrasive layer 102 has a three-dimensional structure constructed with a plurality of three-dimensional elements 104 arranged in a regular manner, having a predetermined shape. The three-dimensional elements 104 each have a tetrahedral shape in which the edges are connected at a point on the upper part. In this case, the angle α formed between two edges is typically 30 to 150 °, preferably 45 to 104 °. The three-dimensional elements 104 may have a pyramidal shape. In this case, the angle formed between two edges is typically 30 to 150 °, preferably 45 to 140 °. The dots on top of the three-dimensional elements 104 are located on a plane parallel to the surface of the base material, substantially above a complete region of the abrasive material. In Figure 1 the symbol h represents the height of the three-dimensional elements 104 of the surface of the base material. The height h is typically from 2 to 300 μp, preferably from 5 to 150 μ ??. The variation of the height of the points on the upper part is preferably less than 20%, more preferably less than 10%, of the height of the three-dimensional elements. The three-dimensional elements 104 are arranged in a predetermined configuration. In Figure 1, the three-dimensional elements 104 are packaged in the most solid form. Typically the three-dimensional elements are repeated with a predetermined period. This repetitive form is unidirectional or preferably bidirectional. The abrasive grains do not protrude beyond the surface of the shape of the three-dimensional elements. In other words, the three-dimensional elements 104 are constructed with smooth planes. For example, the surfaces constituting the three-dimensional elements 104 have a surface roughness Ra less than 2 μp ?, preferably less than 1 and m. In the three-dimensional element 104, its upper portion 105 performs an abrasive function. While the abrasive material is subjected to abrasion, the three-dimensional elements decompose starting from the upper portion, thereby allowing unused abrasive grains to appear. Therefore, in order to increase the abrasive property of the abrasive material, the concentration of the abrasive grains, in the abrasive compound located in the upper portion of the three-dimensional element, is preferably increased to be as high as possible, such as that the abrasive material may have a superior abrasive property so that it is suitable for abrading a hard material. The concentration of the abrasive grains, in the abrasive compound located in the upper portion of the three-dimensional element, more preferably exceeds the critical volumetric concentration of the pigment. Generally the critical volumetric concentration of the pigment is considered as the volumetric concentration of the pigment where there is barely enough binder to coat the pigment surface and provide a continuous phase throughout the film. The critical volumetric concentration of the pigment as it is used herein, means a volumetric concentration of abrasive grains when the free spaces between the grains are just filled with a binder. In the case where the binder is liquid, the mixture has fluidity if the concentration is lower than the critical volumetric concentration of the pigment, while the mixture loses its fluidity if the concentration exceeds the critical volumetric concentration of the pigment. If the concentration of the abrasive grains in the abrasive compound located in the upper part of the three-dimensional element is less than or equal to the critical volumetric concentration of the pigment, the abrasive property of the abrasive material will be insufficient, so that the abrasive material will not be suitable for abrasion of a hard material such as an end surface of a fiber optic connector. The base portion 106 of the three-dimensional element, especially the lower portion of the abrasive layer adhering to the base material, usually does not perform an abrasion function. This is because if the abrasive layer wears away in the lower portion, the abrasive material is usually discarded. The base portion 106 of the three-dimensional element that does not perform the abrasion function need not contain abrasive grains, such that the base portion 106 can be made solely from the binder.

By allowing the three-dimensional element 104 to have that two-layer structure, a saving in the amount of abrasive grains which are comparatively expensive can be achieved, whereby the abrasive material can be provided at a lower cost. Further, since the binder in the base portion 106 can be designed considering only the adhesive power of the binder to the base material, poor adhesion to the base material hardly occurs. In Figure 1, the symbol s represents the height of the upper portion 105 of the three-dimensional element. The height s is, for example, from 5 to 95%, preferably from 10 to 90%, of the height h of the three-dimensional element. Figure 2 is a plan view of this abrasive material. Figure 2, the symbol or represents the length of the lower side of the three-dimensional element. The symbol p represents the distance between the upper parts of the adjacent three-dimensional elements. The length or is, for example, from 5 to 1000 μp ?, preferably from 10 to 500 μ ??. The distance p is, for example, from 5 to 1000] and preferably from 10 to 500 μp ?. In another embodiment, the three-dimensional element may have a tetrahedral or pyramidal shape, whose upper part is truncated to a predetermined height. In this case, the upper part of the three-dimensional element is preferably formed of a triangular or quadrangular plane, parallel to the surface of the base material, and substantially all of these planes are preferably located on a plane parallel to the surface of the base material. The height of the three-dimensional element is from 5 to 95%, preferably from 10 to 90%, of the height h of the three-dimensional element before the truncation of the upper part. Figure 3 is a plan view of the abrasive material according to that embodiment. Figure 3, the symbol or represents the length of the lower side of the three-dimensional element. The symbol u represents a distance between both sides of the adjacent three-dimensional elements. The symbol y represents the length of one side of the top plane. The length or is, for example, from 5 to 2000 μp ?, preferably from 10 to 1000 μm, the distance u is, for example, from 0 to 1000 μp ?, preferably from 2 to 500 μp The length y is, for example , from 0.5 to 1800 μp ?, preferably from 1 to 900 μp ?. Figure 4 is a sectional view, in perspective, of an abrasive material having an abrasive layer of a three-dimensional structure in accordance with another embodiment of the present invention. An abrasive material 400 is an abrasive material having a material base 401 and an abrasive layer 402 placed on the surface of the base material. The abrasive layer 402 has an abrasive compound containing a matrix of a binder and abrasive grains 403 dispersed therein as building components. The abrasive layer 402 has a three-dimensional structure constructed with a plurality of three-dimensional elements arranged in a regular manner, having a predetermined shape. The three-dimensional elements 404 have a prismatic shape formed of a laterally placed triangular prism. The angle β of the three-dimensional element 404 is typically 30 to 150 °, preferably 45 to 140 °. The edges on top of the three-dimensional elements 404 are located on a plane parallel to the surface of the base material, substantially above a complete region of the abrasive material. In Figure 4, the symbol h represents the height of the three-dimensional element, from the surface of the base material. The height h is typically from 2 to 600 μ ??, preferably from 4 to 300 μ ??. The variation of the height of the upper lines is preferably less than 20%, more preferably less than 10%, of the height of the three-dimensional element 404.

Like the three-dimensional element 104, the three-dimensional element 404 preferably has a two-layer structure including an upper portion 405 made of an abrasive compound and a base portion 406 made of a binder. In Figure 4, the symbol s represents the height of the upper portion of the three-dimensional element. The height s is, for example, from 5 to 95%, preferably from 10 to 90%, of the height h of the three-dimensional element. Typically, the three-dimensional elements 404 are arranged in a pattern of stripes. In Figure 4, the symbol w represents the length of the short bottom side of the three-dimensional element (the width of the three-dimensional element). The symbol p represents the distance between the upper parts of the adjacent three-dimensional elements. The symbol represents the distance between the long bottom sides of the adjacent three-dimensional elements. The length w is, for example, from 2 to 2000 μp ?, preferably from 4 to 1000 μp ?. The distance p is, for example, from 2 to 4000 um, preferably from 4 to 2000 μp ?. The distance is, for example, from 0 to 2000 μp ?, preferably from 0 to 1000 μ? T ?. The length of the three-dimensional element can extend substantially above a complete region of the abrasive material. Alternatively, the length of the three-dimensional element can be cut to an appropriate length. The ends of the three-dimensional elements may be aligned or not aligned. The ends of the three-dimensional prismatic elements can be cut at an acute angle from their bottom, to form a house shape having four inclined surfaces. Figure 5 is a plan view of the abrasive material according to this embodiment. In Figure 5 the symbol 1 represents the length of a long lower side of the three-dimensional element. The symbol b represents the distance of a portion of the three-dimensional element cut with an acute angle. The symbol x represents the distance between the short bottom sides of adjacent three-dimensional elements. The symbols w, p and u have the same meanings as in Figure 4. The length 1 is, for example, from 5 to 10000 μm, preferably from 10 to 5000 μp ?. The distance b is, for example, from 0 to 2000 μm, preferably from 1 to 1000 xm. The distance x is, for example, from 0 to 2000 μt, preferably from 0 to 1000 μp ?. The length is, for example, from 2 to 2000 μp, preferably from 4 to 1000 μm. The distance p is, for example, from 2 to 4000 μ ??, preferably from 4 to 2000 μp ?. The distance u is, for example, from 0 to 2000 μ? T ?, preferably from 0 to 1000 μp ?. The abrasive material that has a layer abrasive of a three-dimensional structure of the present invention, exemplified in Figures 1 to 5, is particularly for use in abrading an end surface of a fiber optic connector, and can provide an end surface of an optical fiber connector, with an extremely small connection loss. For example, the abrasive material having an abrasive layer of a three-dimensional structure in accordance with the present invention, provides an end surface of an optical fiber connector, with a connection loss less than 1.0 dB, or less than 0.5 dB. The abrasive material of the present invention is preferably produced by the method described below. First, an abrasive liquid paste containing abrasive grains, a binder, and a solvent is prepared. The liquid abrasive paste to be used herein is a composition containing the binder, the abrasive grains, and optional additives such as a photoinitiator, in amounts sufficient to constitute an abrasive compound and additionally contains a volatile solvent in a sufficient amount to impart fluidity to the mixture. Even if the content of abrasive grains in the abrasive compound exceeds the critical volumetric concentration of the pigment, fluidity can be maintained allowing the liquid abrasive paste to contain a volatile solvent. A preferred volatile solvent is an organic solvent that dissolves the binder and exhibits volatility at room temperature up to 170 ° C. Specific examples of the organic solvent include methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, tetrahydrofuran, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate. Another preferred solvent is water. Subsequently, a molding sheet is prepared having a plurality of cavities arranged in a regular shape and tapering towards the bottom. The shape of the cavities can be the inverse of the three-dimensional elements that are to be formed. The molding sheet can be made of a metal such as nickel or of plastics such polypropylene. For example, a thermoplastic resin such as polypropylene is preferred because it can be embossed at its melting point on a metal tool, to form cavities in a predetermined manner. Furthermore, if the binder is a resin of the type that is cured by radiation, it is preferable to use a material that transmits ultraviolet and visible light. Figures 6 (a) through 6 (e) are views of models that show the steps for producing an abrasive material having an abrasive layer of a three-dimensional structure. With reference to Figure 6 (a), the obtained molding sheet 601 is filled with an abrasive liquid paste 602. The amount of the liquid abrasive paste to be taped in the filling of the molding sheet is such that it can forming an upper portion 105, 405, after the solvent evaporates and the binder hardens. Typically, the amount of liquid abrasive paste can be such that its depth from the bottom is a dimension s shown in Figures 1 and 4 after evaporation of the solvent. The molding sheet can be filled with a liquid abrasive paste by applying the liquid abrasive paste to the molding sheet by a coating apparatus such as a roller coater. The viscosity of the abrasive liquid paste for the application is preferably adjusted to be 10 to 106 cps, particularly 100 to 105 cps. Referring to Figure 6 (b), the solvent is evaporated and removed from the abrasive liquid paste. When this is done, the molding sheet filled with the abrasive liquid paste is heated from 50 to 150 ° C for a time of 0.2 to 10 minutes. If the binder is a thermoplastic resin, the molding sheet can be heated to its curing temperature to simultaneously carry out a hardening step. If the solvent volatility is high, the molding sheet may be allowed to stand at room temperature for several minutes to several hours. Referring to Figure 6 (c), the molding sheet is further filled with a binder 603 for lamination to fill the cavities with the binder. The rolling binder can be the same or different from that used in the preparation of the liquid abrasive paste. A binder having good adhesion to the base material is preferable as the laminating binder. Preferred examples of the laminating binder are the acrylate resin, the epoxy resin, and the urethane resin. The molding sheet can be filled with the laminating binder in the same manner as the liquid abrasive paste. Referring to Figure 6 (d), a base material 604 is superimposed on the molding sheet 601 to allow the binder to adhere to the base material. The adhesion is carried out by exerting pressure with a roller for lamination. The binder hardens. The term "hardening", as used herein, means that the binder polymerizes to a solid state. After curing, the specific shape of the abrasive layer does not change. The hardening of the binder in the liquid abrasive paste and the hardening of the laminating binder introduced individually in the last step, they can be carried out either separately or simultaneously. The binder is hardened by heat, infrared radiation or by electron beam radiation, ultraviolet radiation, or by other radiant energy such as visible light radiation. The amount of radiant energy to be applied may vary depending on the type of binder and the radiant energy source. Usually, those skilled in the art can appropriately determine the amount of radiant energy to be applied. The period of time required in the hardening may vary depending on the thickness, density, temperature of the binder, properties of the composition, and other factors. For example, the binder can be hardened by radiant ultraviolet (UV) rays from above the transparent base material. Referring to Figure 6 (e), the molding sheet is removed to produce an abrasive material 606 composed of the base material 604 and the abrasive layer 605 having a three-dimensional structure. He Binder can harden after the molding sheet is removed.

Examples The present invention will be described in greater detail by the following examples. However, the present invention is not limited by these examples.

Example 1 A coating solution of the abrasive material was prepared by mixing the components shown in Table 1.

Table 1 Table 1 (Continued) Proportion of abrasive grains / binder Proportion of abrasive grains / (binders + additives) A lamination binder was prepared by mixing the components shown in Table 2.

Table 2 A molding sheet made from polypropylene was prepared and having cavities with a shape of inverted three-dimensional elements shown in Figure 4. An abrasive liquid paste was applied on the molding sheet by a roller coater and dried at 50 ° C. C for 5 minutes. A laminating binder was applied thereon and additionally a film of transparent polyester that had a thickness of 75 μp? it was overlapped and pressed by rolling for rolling. Ultraviolet rays were irradiated from the side of the polyester film to harden the laminating binder. Subsequently, the binder of the abrasive liquid paste was cured by heating at 70 ° C for 24 hours. The molding sheet was removed and the resulting product was cooled to room temperature to produce an abrasive material. In the abrasive material the abrasive layer had a three-dimensional structure having a prismatic shape disposed in a pattern of stripes shown in Figure 4. The dimensions thereof are presented in Table 3.

Table 3 This abrasive material was punched for produce a circular shape that had a diameter of 110 mm to make an abrasive disk. An end surface of a splice sleeve for optical connector was worn with the use of the obtained abrasive disk. The abrasion conditions are presented in Table 4.

Table 4 The change over time of the weathered amount is shown in Figure 7. After abrasion, the end surface of the splice sleeve of the optical connector was observed by electron microscopy, with which a smooth surface was confirmed. The obtained microscope photograph is presented in the Figure Example 2 An abrasive liquid paste was prepared by mixing the components shown in Table 5.

Table 5 Proportion of abrasive grains / binder = 2. 86 Proportion of abrasive grains (binder + additives) An abrasive disk was manufactured in the same manner as in Example 1, except that this liquid abrasive paste was used, and an end surface of a splice sleeve of the optical connector was worn. The change over time of the worn amount is presented in Figure 7. After the abrasion, the end surface of the splice sleeve of the optical connector was observed, by means of an electron microscope, whereby a smooth surface was confirmed. The microscope photograph, obtained, is shown in Figure 9.

Comparative Example 1 An abrasive material "Imperial Sign Diamond, 3 Mil Millimeters and 3 Microns, Type H", manufactured by Minnesota Mining and Manufacturing Co., Ltd was die cut to produce a circular shape with a diameter of 110 mm, to make a disc abrasive. An end surface of a splice sleeve of the optical connector was subjected to abrasion in the same manner as in Example 1, except that this abrasive disk was used. The change over time of the weathered quantity is shown in Figure 7. After the abrasion, the end surface of the splice sleeve of the optical connector was observed through a microscope electronic, for which a rough surface was confirmed. The obtained microscope photograph is shown in Figure 10.

Comparative Example 2 The abrasive liquid paste prepared in Example 1 was applied on a polyester film having a thickness of 75 μp ?, by a knife coater and the solvent was removed by evaporation to form an abrasive layer having a thickness of 11 μ? . The abrasive layer was heated at 70 ° C for 24 hours to harden the binder. The abrasive material was die cut to produce a circular shape having a diameter of 110 mm in order to manufacture an abrasive disk. An end surface of a splice sleeve of the optical connector was subjected to abrasion in the same manner as in Example 1, except that this abrasive disk was used. The change over time of the weathered quantity is shown in Figure 7. After abrasion, the end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a rough surface was confirmed. The obtained microscope photograph is shown in Figure 11.

Comparative Example 3 The abrasive liquid paste prepared in Example 2 was applied on a polyester film having a thickness of 75 and m, by a knife coater and the solvent was removed by evaporation to form an abrasive layer having a thickness of 11 μp ?. The abrasive layer was heated at 70 ° C for 24 hours to harden the binder. The obtained abrasive material was punched out to produce a circular shape having a diameter of 110 mm in order to manufacture an abrasive disk. An end surface of a splice sleeve of the optical connector was subjected to abrasion in the same manner as in Example 1, except that this abrasive disk was used. The change over time of the abraded amount is presented in Figure 7. After abrasion, the end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a rough surface was confirmed. The obtained microscope photograph is presented in Figure 12. Comparing Figures 8 and 9 with Figure 10, it will be understood that the abrasive materials of Examples 1 and 2 provide a smoother worn surface than the abrasive material of Comparative Example 1 on Which is a common product. Also, comparing Figure 8 with Figure 11 it will be understood that the abrasive material of Example 1 provides a smoother surface than the abrasive material of Comparative Example 2 which is an abrasive material made from the same liquid paste but having an abrasive layer without a three-dimensional structure. Comparing Figure 9 with Figure 12, it will be understood that the abrasive material of Example 2 provides a smoother surface than the abrasive material of Comparative Example 3, which is an abrasive material made from the same liquid paste but having an abrasive layer without a three-dimensional structure. From the graph shown in Figure 7, it will be understood that the abrasive disc of Example 2 exhibits a superior abrasive property than the abrasive discs of Comparative Examples 1 to 3.

Example 3 An abrasive liquid paste was prepared by mixing the components shown in Table 6.

Table 6 Abrasive grains / binder ratio = 2.00 Abrasive grains ratio / (binder + additives) = 1. 96 The same molding sheet made of polypropylene was prepared, such as that used in Example 1. A liquid abrasive paste was applied on the molding sheet, by a roller coater, and dried at 60 ° C for 5 minutes. A lamination binder, prepared in Example 1, was applied thereon, and in addition, a transparent polyester film, having a thickness of 75 μm, was superimposed and pressed by a roll for rolling. Ultraviolet rays were irradiated from the side of the polyester film to harden the binder. The molding sheet was removed and the resulting product was cooled to room temperature to produce an abrasive material. This abrasive material was punched to produce a circular shape having a diameter of 110 mm to make an abrasive disk. At the same time an optical connector splice sleeve was prepared and an end surface thereof was abraded, under the same abrasion conditions as in Table 7, with the use of an abrasive material "Imperial Diamond Signal Film of 3 Thousand Inches and 0.5 Microns Type H" manufactured by Minnesota Mining and Manufacturing Co., Ltd. An extreme surface of this optical connector splice sleeve was subjected to further abrasion with the use of the manufactured abrasive disk. The abrasion conditions are presented in Table 7.

Table 7 After the abrasion, the end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a smooth surface was confirmed. The obtained microscope photograph is shown in Figure 13. The shape of the end surface of the splice sleeve of the optical connector, after abrasion, was measured by a "ZX-1 ini PMS approach" interferometer manufactured by Direct Optical Research Company (DORC) and the amount of reflected damping was measured by a "RM300A Black Reflection Measure" manufactured by JDS FITEL. The results are presented in Table 9.

Example 4 An abrasive liquid paste was prepared mixing the components shown in Table 8 Table 8 Abrasive grains / binder ratio Abrasive grains / proportion (binder + additives) = 1.96.

An abrasive disk was manufactured in the same manner as in Example 3, except that this abrasive liquid paste was used, and an end surface of a splice sleeve of the optical connector was subjected to abrasion. A microscope photograph of the end surface, after abrasion, is presented in Figure 14. The shape of the end surface and the amount of reflected damping are presented in Table 9.

Comparative Example 4 An abrasive material "Imperial Sign Diamond, 3-mil and 0.05 Micron AO Type P", manufactured by Minnesota Mining and Manufacturing Co., Ltd, was die-cut to produce a circular shape having a diameter of 110 mm, in order to to make an abrasive disk. An end surface of an optical connector splice sleeve was subjected to abrasion in the same manner as in Example 3, except that this abrasive disk was used. A microscope photograph of the end surface, after abrasion, is presented in Figure 15. The shape of the end surface and the amount of reflected damping are presented in Table 9.

Comparative Example 5 The liquid abrasive paste prepared in Example 3 was applied on a pster film having a thickness of 75 μp ?, by means of a knife coater, and the solvent was removed by evaporation, to form an abrasive layer having a thickness of 4 μm. . A pster film that had a thickness of 31 μp? it was laminated on this abrasive layer, and the binder was hardened by irradiation of ultraviolet rays. The obtained abrasive material was punched out to produce a circular shape having a diameter of 110 mm in order to manufacture an abrasive disk. An end surface of an optical connector splice sleeve was subjected to abrasion in the same manner as in Example 3, except that this abrasive disk was used. However, the adhesions accumulated on the extreme surface during the abrasion made it impossible to carry out an effective abrasion.

Comparative Example 6 The abrasive liquid paste prepared in Example 4 was applied on a pster film having a thickness of 75 μp ?, by a knife coater, and the solvent was removed by evaporation to form a layer abrasive that had a thickness of 4 μp ?. A pster film that had a thickness of 31 μ ?? it was laminated on this abrasive layer, and the binder was hardened by irradiation of ultraviolet rays. The obtained abrasive material was punched out to produce a circular shape having a diameter of 110 mm in order to manufacture an abrasive disk. An end surface of an optical connector splice sleeve was subjected to abrasion in the same manner as in Example 3, except that this abrasive disk was used. However, the adhesions accumulated on the extreme surface during the abrasion made it impossible to carry out an effective abrasion.

Table 9 Table 9 (Continued) Samples of Example 3 Example 4 Example 4 Ex Comp materials 4 abrasives Height of 28.0 7. 7 9.4 8. 4 -60.3 34 .9 -31 .5 3. 9 fiber 6 (spherical adjustment: nm) Height of fiber 163 20 .7 132.9 38 .9 52.9 10 .1 106 .1 8. 7 (flat setting: 0 nm) Diameter (m) 126. 0. 3 126.7 0. 3 126.6 0. 3 127 .3 0. 4 9 Quantity 46.1 0. 2 44.7 1 1 47.3 2 2 41. 7 0. 5 Damping reflected (dB) As shown in Figures 13 and 14, when the abrasive materials of Examples 3 and 4 were used, the abrasion striae created by abrasion with the "Imperial Diamond Sign Diamond 3-mil. Type H "manufactured by Minnesota Mining and Manufacturing Co., Ltd (Figure 10) disappeared by abrasion of 60 seconds. This end surface of the splice sleeve of the optical connector had been subjected to extremely smooth and fine abrasion, as shown in Table 9, and the amount of reflected damping was extremely small compared to Comparative Example 4. The abrasive material of Example 4 showed an extremely good result when the abrasion was performed with the use of 2-propanol as the cooling liquid.

Example 5 An abrasive liquid paste was prepared by mixing the components shown in Table 10.

Table 10 Table 10 (Continued) Abrasive grains / binder ratio = 2.72 Abrasive grains ratio / (binder + additives) = 2. 69 The same molding sheet made of polypropylene as the one used in Example 1 was prepared. applied an abrasive liquid paste on the molding sheet, by means of a roller coater, and dried at 70 ° C for 5 minutes. A laminating binder prepared in Example 1 was applied thereon and additionally, a transparent polyester film, having a thickness of 75 μm, was superimposed and pressed by a roller for lamination. Ultraviolet rays were irradiated from the side of the polyester film, to harden the laminating binder. Subsequently, the binder in the abrasive liquid paste was cured by heating at 70 ° C for 24 hours. The resulting product was cooled to room temperature and the molding sheet was removed to produce an abrasive material. This abrasive material was punched out to produce a circular shape having a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod (diameter: 3 mm) was subjected to abrasion with the use of the manufactured abrasive disc. The abrasion conditions are presented in Table 11.

Table 11 The change with respect to the time of the worn amount is presented in Figure 16. Subsequently, the abrasive disk was replaced with a new one, and the end surface of the splice sleeve of the optical connector was subjected to abrasion. The abrasion condition is presented in Table 12.

Table 12 After the abrasion, the end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in Figure 17.

Example 6 An abrasive material was made in the same manner as in Example 5, except that a molding sheet made of polypropylene was used and that it had cavities with a shape of inverted three-dimensional elements, shown in Figure 5. In this abrasive material, the The abrasive layer had a three-dimensional house-shaped structure, arranged in a stripe pattern as shown in Figure 5. The dimensions are presented in Table 13.

Table 13 Table 13 (Continued) The symbols h, s, and ß represent the height of the three-dimensional element, the height of the upper portion of the three-dimensional element, and the angle shown in Figure 4, respectively. The obtained abrasive material was punched to produce a circular disk having a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod and an end surface of an optical connector splicing sleeve, was subjected to abrasion with the use of this abrasive disk, in the same manner as in Example 5. The change with respect to time, of the amount Worn from the circular zirconia rod, is presented in Figure 16. The end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a smooth surface was confirmed.

A photograph of the microscope is presented in Figure 18.

Example 7 An abrasive material was manufactured in the same manner as in Example 5, except that a molding sheet made of polypropylene was used and had cavities with a shof inverted three-dimensional elements shown in Figures 1 and 2. In this abrasive material, the abrasive layer had a three-dimensional structure of a tetrahedral sh most solidly packaged, as shown in Figures 1 and 2. The dimensions are presented in Table 14.

Table 14 The obtained abrasive material was punched to produce a circular disc having a diameter of 110 mm to make an abrasive disk. A circular zirconia rod and an end surface of an optical connector splice sleeve were subjected to abrasion with the use of this abrasive disk, in the same manner as in Example 5. The change with respect to time, the Worn amount of the circular zirconia rod is presented in Figure 16. The end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in Figure 19.

Example 8 An abrasive material was manufactured in the same manner as in Example 5, except that a molding sheet made of polypropylene was used and had cavities with a shof inverted three-dimensional elements shown in Figure 4, and of a different type than that it was used in Example 5. In this abrasive material, the abrasive layer had a three-dimensional structure of a prismatic sharranged in a pattern of stripes as shown in Figure 4. The dimensions are presented in Table 15.

Table 15 The obtained abrasive material was punched to produce a circular disk having a diameter of 110 mm in order to manufacture an abrasive disk. A circular zirconia rod and an end surface of an optical connector splice sleeve were subjected to abrasion with the use of the abrasive disk, in the same manner as in Example 5. The change with respect to time, of the amount weathered of the circular zirconia rod is presented in Figure 16. The end surface of the junction sleeve of the optical connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in Figure 20.

Comparative Example 7 An abrasive material "Imperial Sign Diamond with 3 mils and 9 Microns, Type H" manufactured by Minnesota Mining and Manufacturing Co., Ltd, was die cut to produce a circular shhaving a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod and an end surface of an optical connector splice sleeve were subjected to abrasion in the same manner as in Example 5, except that this abrasive disk was used. The change with respect to time, of the worn amount of the circular zirconia rod, is presented in Figure 16. The end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a rough surface was confirmed . A photograph of the microscope is presented in Figure 21.

Comparative Example 8 The abrasive liquid paste prepared in Example 5 was applied on a polyester film having a thickness of 75 μp ?, by means of a knife coater and the solvent was removed by evaporation, to form an abrasive layer having a thickness of 14 μp? . The abrasive layer is heated at 70 ° C for 24 hours and further heated at 100 ° C for 24 hours to harden the binder. The abrasive material obtained by cooling to room temperature was die cut to produce a circular shhaving a diameter of 110 mm in order to manufacture an abrasive disk. A circular zirconia rod and an end surface of an optical connector splice sleeve, were subjected to abrasion in the same manner as in Example 6, except that this abrasive disk was used. The change with respect to time, of the worn amount of the circular zirconia rod, is presented in Figure 16. The end surface of the splice sleeve of the optical connector was observed by an electron microscope, whereby a rough surface was confirmed . A photograph of the microscope is presented in Figure 22.

Example 9 An abrasive liquid paste was prepared by mixing the components presented in Table 16.

Table 16 Proportion of abrasive grains / binder = 2.86 Proportion of abrasive grains / (binder + additives) A laminating binder was prepared by mixing the components presented in Table 17.

Table 17 The same molding sheet made of polypropylene was prepared as used in Example 1. A liquid abrasive paste was applied on the molding sheet by a knife coater, and dried at 70 ° C for 5 minutes. The laminating binder was applied thereon and in addition, a transparent polyester film, having a thickness of 75 μp ?, was superimposed and pressed by a roller for lamination. Ultraviolet rays were irradiated from the side of the polyester film to harden the laminating binder. Subsequently, the binder in the liquid paste abrasive was hardened by heating at 70 ° C for 24 hours. The resulting product was cooled to room temperature and the molding sheet was removed. The binder in the abrasive layer was hardened by further heating to 100 ° C for 24 hours. This abrasive material was punched to produce a circular shape having a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod, and an end surface of a fiber optic splice sleeve, were subjected to abrasion in the same manner as in Example 5, except that this abrasive disk was used. The change with respect to time, of the worn amount of the rods of zirconia, circular, is presented in Figure 16. The end surface of the fiber optic connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in Figure 23.

Example 10 An abrasive material was manufactured in the same manner as in Example 9 except that the same molding sheet made of polypropylene was used, as was used in Example 6. This abrasive material was punched out to produce a circular shape having a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod, and an end surface of a fiber optic connector, were subjected to abrasion in the same manner as in Example 5, except that this abrasive disk was used. The change with respect to time, of the worn amount of the circular zirconia rod, is presented in Figure 16. The end surface of the fiber optic connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in. Figure 24.

Example 11 An abrasive material was made in the same manner as in Example 9, except that a molding sheet made of polypropylene was used and that it had cavities with a shape of inverted three-dimensional elements shown in Figure 3. In this abrasive material, the layer abrasive had a three-dimensional structure of a pyramidal shape shown in Figure 3, in which the upper part is truncated at a predetermined height. The dimensions are presented in Table 18.

Table 18 The symbols h, s and a represent the height of the three-dimensional element, the height of the upper portion of the three-dimensional element, and the angle formed between two edges of the three-dimensional element before the upper part is truncated, respectively. The obtained abrasive material was punched out to produce a circular shape having a diameter of 110 mm, in order to manufacture an abrasive disk. A circular zirconia rod, and an end surface of a fiber optic connector, were subjected to abrasion in the same manner as in Example 5, except that this abrasive disk was used. The change with respect to time, of the worn out amount of the circular zirconia rod, is presented in Figure 16.

The extreme surface of the fiber optic connector was observed by an electron microscope, whereby a smooth surface was confirmed. A photograph of the microscope is presented in Figure 25. From the graph shown in the Figure 16, it will be understood that the abrasive discs of examples 5 to 11 exhibit a superior abrasive property and a longer product life, as compared to the abrasive discs of Comparative Examples 7 and 8. Also, comparing Figures 17 to 20 and from 23 to 25, with Figures 21 and 22, it will be understood that the abrasive discs of Examples 5 to 11 provide a smoother worn surface, than the abrasive disc of Comparative Example 7 which is a common product and that the abrasive disk of Comparative Example 8 having an abrasive layer without a three-dimensional structure. Since this invention can be incorporated in various forms, without departing from the spirit of the essential features thereof, the present embodiment is then illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description that precedes them, and all changes that fall within the boundaries and boundaries of the claims, or equivalence of those limits or borders, then intend to be covered by the claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (21)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A method for producing an abrasive material having an abrasive layer of a three-dimensional structure, the method is characterized in that it comprises the steps of: (1) filling a molding sheet having a plurality of cavities disposed in a regular manner, with a coating solution of abrasive material containing abrasive grains, a binder, and a solvent, to a predetermined depth; (2) removing the solvent from the coating solution of abrasive material, which is found in the cavities, by evaporation; (3) filling the cavities additionally with a binder in the absence of abrasive particles; (4) laminating a base material on the molding sheet, to bond the binder to the base material; and, (5) hardening the binder. 2. The method according to claim 1, characterized in that the binder is hardened by ultraviolet radiation. 3. The method according to claim 1, characterized in that the binder contained in the coating solution of abrasive material used in step (1) is selected from the group consisting of phenolic resin, aminoplast resin, urethane resin, epoxy resin, resin of acrylate, acrylated isocyanurate resin, urea-forinaldehyde resin, isocyanurate resin. Acrylated urethane resin, acrylated epoxy resin, phenolic resole resin, polyester resin, vinyl resin, melamine resin and a mixture thereof. 4. The method according to claim 1, characterized in that the binder used in step (3). it is selected from the group consisting of phenolic resin, aminoplast resin, urethane resin, epoxy resin, acrylate resin, acrylated isocyanurate resin, urea-formaldehyde resin, isocyanurate resin, acrylated urethane resin, acrylated epoxy resin, resole resin -phenolic, polyester resin, vinyl resin, melamine resin and a mixture thereof. 5. An abrasive material for abrading an end surface of a fiber optic connector to produce a predetermined shape, the abrasive material having a base material and an abrasive layer placed on the base material, the abrasive layer having a structure three-dimensional constructed with a plurality of three-dimensional elements arranged in a regular manner, having a predetermined shape. the three-dimensional elements have (1) an upper layer comprising an abrasive composite containing abrasive grains dispersed with a binder, and (2) a base portion comprising. a binder in the absence of abrasive particles, 6. The abrasive material according to claim 5, characterized in that the upper parts of the three-dimensional elements are -constructed with points. or lines parallel to a surface of the base material, and substantially all of those points or lines are located on a plane parallel to the surface of the base material. The abrasive material according to claim 5, characterized in that the concentration of the abrasive grains in the upper layer of the abrasive layer "exceeds a critical volumetric concentration of pigment 8. The abrasive material according to claim 5, characterized in that the shape of the three-dimensional elements is a tetrahedral or pyramidal shape, having edges connected in an upper part. 9. The abrasive material according to claim 5, characterized in that the three-dimensional elements have a height between approximately 2 microns and approximately 300 microns. 10. The abrasive material according to claim 9, characterized in that the height of the three-dimensional elements varies less than 20%. 11. The abrasive material according to claim 5, characterized in that the shape of the three-dimensional elements is a prismatic shape having parallel edges to a surface of the base material in an upper part. 12. The abrasive material according to claim 5, characterized in that the size of the abrasive grains is between approximately 0.01 and approximately 1 micrometer. 13. The abrasive material according to claim 5, characterized in that the size of the abrasive grains is between about 0.5 and about 20 microns. The abrasive material according to claim 5, characterized in that the nominal size of the abrasive grains is between / about 2 and about 4 microns. 15. The abrasive material in accordance with claim 5, characterized in that the nominal size of the abrasive grains is between about 7 and about 10 microns. 16. The abrasive material according to claim 5, characterized in that the maximum size of the abrasive grains is approximately 16 micrometers. 17. The abrasive material according to claim 5, characterized in that the average size of the abrasive grains is between about 7.5 and about 9.5 microns. 18. The abrasive material according to claim 5, characterized in that the binder is selected from the group consisting of phenolic resin, aminoplast resin, urethane resin, epoxy resin, acrylate resin, acrylated isocyanurate resin, urea-formaldehyde resin , isocyanurate resin, acrylated urethane resin, acrylated epoxy resin, phenol-resole resin, polyester resin, vinyl resin, melamine resin, and mixtures thereof. The abrasive material according to claim 5, characterized in that "the abrasive grains are selected from the group consisting of fused aluminum oxide, heat-treated aluminum oxide, silicon carbide, alumina zirconia, garnet, diamond, nitride cubic boron, silica, cerium oxide, aluminum oxide sol-gel, chromium oxide, zirconia, iron oxide and mixtures thereof. The abrasive material according to claim 5, characterized in that the base material is flexible so that it is particularly suitable for spherically wearing an end surface of a fiber optic connector. 21. The abrasive material according to claim 20, characterized in that it is capable of providing an end surface of an optical fiber connector, having a connection loss not greater than 1.0 dB.