JP2001113467A - Polishing sheet and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing sheet and a manufacturing method therefor capable of performing a polishing process with efficiency corresponding to mechanical polishing, capable of developing the polishing sheet of not damaging an end surface of an optical fiber by grinding chips and not reducing an optical characteristic by sticking to the end surface and capable of working the optical fiber capable of improving the optical characteristic from a zirconia ferrule so as to become a slightly projecting shape. SOLUTION: In a polishing sheet having a polishing layer 5 on a recess/ projection surface 2 of a base material sheet 1 having a recess/projection shape on a base material sheet surface, the polishing sheet 10 is constituted so that the average particle size of an abrasive grain 4 contained in the polishing layer becomes 10 to 200 mμ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet which is polished without supplying a liquid abrasive containing abrasive grains in a polishing step of an end face of a connector of an optical fiber. By using this, there is no step between the optical fiber and the ferrule, and there is no damage to the end of the optical fiber due to the attachment of abrasive powder (grinding debris). In addition, the present invention belongs to a polishing sheet applicable to an end face of an optical fiber connector capable of realizing an improvement in optical characteristics and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the transmission path of optical communication, in order to suppress optical loss and achieve efficient information transmission, it is a major problem to improve an optical fiber connector which accounts for a large proportion of the loss. The performance of the optical fiber connector depends on the accuracy of the polishing step for final finishing the end face. Therefore, precision parts, such as optical fibers and semiconductor wafers, are processed by a multi-stage polishing process. However, the quality depends on the accuracy of the polishing process for performing the final mirror finish. Conventionally, in order to polish without a step between an optical fiber surface and a ferrule and without damaging an end surface of the optical fiber, mechanical polishing using a polishing liquid containing abrasive grains and a polishing cloth has been performed. In addition, since the above-described method using a polishing liquid complicates the polishing step, an alternative method uses a polishing sheet provided with various polishing layers. This polishing sheet is mainly made of plastics. Abrasive grains are bonded to a smooth base sheet for a polishing sheet, and the abrasive grains are fixed to the base sheet. Synthetic / natural resins, plasticizers, lubricants And an antistatic agent.)
Is dispersed and applied. In other words, a coating liquid in which abrasive grains are dispersed in a resin varnish (a solution in which a binder is dissolved in a solvent suitable for a coating process) is coated and dried, and if necessary, a reaction such as curing is accelerated and completed to polish. It forms a layer.

In mechanical polishing, it is necessary to completely clean a jig after polishing is completed. If the cleaning is insufficient, there is a problem that fine abrasive grains adhered and remaining on the polishing jig become aggregated grains and damage the end face of the optical fiber during the polishing process. In addition, when the amount of grinding dust increases, the end surface of the optical fiber is damaged by the grinding dust or adheres to the end surface, causing a deterioration in optical characteristics. The use of a polishing sheet has a problem that the grinding performance is inferior and the polishing efficiency is poor as compared with the mechanical polishing described above. Then, in order to improve the optical characteristics, it is preferable that the optical fiber be processed so as to be slightly convex than the zirconia ferrule. However, there is a problem that it is difficult to process the abrasive sheet processed into the above-mentioned smooth base sheet so as to be slightly convex.

[0004]

With the efficiency equivalent to mechanical polishing, not only does the end face of the optical fiber not be damaged by grinding chips during the polishing process, nor does the optical property deteriorate by adhering to the end face. An object of the present invention is to provide a polishing sheet that can be processed to be slightly convex from a zirconia ferrule, and a method for manufacturing the same.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a polishing sheet having a polishing layer on an uneven surface of a substrate sheet having an uneven surface, the polishing sheet being included in the polishing layer. This is a polishing sheet having a particle diameter of 100 to 800 mμ. Further, the average center line roughness R of the polishing layer surface
a is 0.1 to 0.5, and is a polishing sheet having a turtle-shaped concave surface. The abrasive sheet forming the polishing layer is a silica particle, and the binder is a polishing sheet containing polyorganosiloxane or a silane coupling agent having a vinyl group or an epoxy group. Also,
The above-mentioned sheet having an uneven surface forming the polishing layer is a polishing sheet made of a polyester film. And, in a polishing sheet having a polishing layer on an uneven surface of a base sheet having an uneven shape on the surface, wherein the particle size of abrasive grains contained in the polishing layer is 100 to 800 mμ, the base sheet Providing a primer on the uneven surface as desired,
Further, the average particle diameter of the abrasive grains is 10 to 200 mμ, and the binder is a polyorganosiloxane, or a coating liquid composed of a resin varnish containing a silane coupling agent having a vinyl group or an epoxy group, the above-mentioned coating liquid is applied. This is a method for producing a polishing sheet for forming a polishing layer of the above.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a polishing sheet 10 according to the present invention is a polishing sheet 10 having a polishing layer 5 on an uneven surface 2 of a base sheet 1 having an uneven surface. The average grain size of the abrasive grains 4 contained in the layer 5 is 100 to 800 mμ
Is a polishing sheet. The center line average roughness Ra of the polishing layer surface 5 is 0.1 to 0.5 μm, and FIG.
Is a polishing sheet 10 having a turtle-shaped concave surface 6 shown in FIG.
The polishing sheet 10 is made of a resin varnish containing silica particles as the particles of the abrasive grains 4 forming the polishing layer 5 and the binder 3 containing a polyorganosiloxane or a silane coupling agent having a vinyl group or an epoxy group. is there. The sheet having the uneven surface 2 for forming the polishing layer 5 is a polishing sheet 1 made of a polyester film.
0.

In a polishing sheet 10 having a polishing layer 5 on an uneven surface 2 of a substrate sheet 1 having an uneven surface, the abrasive grains 4 contained in the polishing layer 5 have an average particle diameter of 100 to 100.
The base sheet 1 is a polishing sheet of 800 μm.
A primer 11 is provided on the uneven surface 2 as desired, and the average grain size of the abrasive grains 4 contained in the polishing layer 5 is 10 to
A polishing sheet for forming the above-mentioned polishing layer 5 by applying a coating liquid comprising a resin varnish containing a polyorganosiloxane or a silane coupling agent having a vinyl group or an epoxy group, the binder 3 of which is 200 mμ. 10
It is a manufacturing method of.

The base sheet used in the polishing sheet of the present invention has excellent moldability capable of forming an irregular shape on the surface, and has sufficient strength to be subjected to polishing work, and has sufficient strength for coating and polishing.
The film can be appropriately selected from a film having strength, heat resistance, and small dimensional change that can withstand drying. For example, high density polyethylene,
Polyolefins such as polypropylene, polystyrene,
Polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, polyacrylonitrile, polyamide, acrylic resin containing acrylate or methacrylate as a main component, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. A stretched or unstretched sheet made of a cellulose derivative such as polyester, polyacetal, di- or tri-cellulose acetate, or polycarbonate.

It is preferable to add an antistatic agent to the base sheet in order to prevent dust from adhering in the working process. As the antistatic agent, ordinary nonionic surfactants, anionic surfactants, cationic surfactants and the like, and polyamide derivatives and acrylic acid derivatives can be appropriately selected and added.

The base sheet is preferably made of polyethylene terephthalate, a biaxially stretched nylon 6 film or a polyimide film having a thickness of 25 to 200 μm, which is excellent in coating suitability of a polishing layer, suitability for post-processing and handling in a polishing machine. To be elected. Then, it is preferable to apply an easy adhesion treatment such as a corona discharge treatment or an ozone gas treatment to the side on which the primer layer or the polishing layer is applied. The base sheet that can be particularly preferably used is a polyester that has many types of constituent materials and is easily modified to obtain desired physical properties. Among them, a biaxially stretched film of polyethylene terephthalate having heat resistance and rigidity and other polyesters Is a film having a thickness of 20 to 200 μm provided as a primer layer.

The uneven shape to be formed on the substrate sheet can be formed by a sand blasting method which is usually performed on one side of the substrate sheet. In addition, the uneven shape can be formed by shaping the uneven shape in the heating embossing step, or, in some cases, curing the coated surface by applying a non-adhesive reactive resin at room temperature and also hardening after embossing, also serving as a primer. It can be shaped.

The abrasive particles forming the polishing layer have an average particle diameter of 10
Silica particles of up to 200 μm, preferably 10 to 100 μm are used. Then, the particle size is selected from those having a particle size of 5,000 to 10,000 mμ which does not include the commonly used coarse particles. By not including such coarse particles, a mirror surface required for the final finish of the end face of the optical fiber, the optical lens, the surface of the semiconductor wafer, etc. is formed, and no polishing scratches or spots are generated. A polishing sheet having no step can be produced.

The preferred abrasive used in the coating liquid of the polishing layer of the present invention is an organosilica sol comprising fine particles having an average particle diameter of 10 to 200 μm. And
100-800m even when fine particles aggregate in the polishing layer
It has a particle size of μ.

Generally, primary particles of 10 to 700 mμ are used as abrasive grains used in a polishing sheet suitable for precision parts. The smaller the particle size of the abrasive, the larger the amount that can be blended into the coating liquid, and the larger the particle size, the smaller the blending amount. And when it is smaller than 10mμ,
If the grinding effect cannot be improved, and if it is more than 800 μm, the material to be polished may be scratched. Therefore, particles of 10 to 800 mμ have been preferably used. Attempts have also been made to use fine particles of 1-2 μm in a polishing sheet for precision parts that require a finer surface finish. Usually, when such ultrafine particles are used, there is a drawback that the grindability is not sufficient and satisfactory polishing properties cannot be obtained. The present invention solves this drawback by providing a polishing layer on an uneven surface of a substrate sheet having an uneven shape.

The binder of the abrasive grains used to form the polishing layer is a polyorganosiloxane resin or a resin varnish containing a silane coupling agent containing an epoxy group or a vinyl group. The adhesion of the binder to the substrate sheet is also strong and can be preferably used.

The binder of the present invention uses an organic / inorganic composite resin, or a prepolymer, oligomer, or polymer having a siloxane bond [siloxane bond: (—Si—O—) n] in its structure. Can be. Then, it is used as a polysiloxane, a derivative or modified product thereof, or a blend thereof.

Specifically, a monomer, prepolymer or oligomer or polymer constituting polysiloxane, and a copolymer mainly containing acrylic resin, polyethylene, vinyl chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, for example. , Rubber-like polymers, polyesters, polyamides, phenolic resins, aminoplasts, epoxy resins, polyurethanes, cellulose derivatives, and other monomers, prepolymers or oligomers or polymers, mixed or reacted, and their blends or reaction products Can be used.

In particular, in the present invention, a vinyl chloride / vinyl acetate copolymer, polyethylene, polyvinyl chloride,
A prepolymer or oligomer or polymer such as polyvinyl acetate, acrylic resin, polyurethane, or polyester is used as a main chain, and a polysiloxane prepolymer, oligomer, or polymer is reacted with a side chain of the main chain by, for example, graft polymerization, and the main chain is converted to an organic compound. It is preferable to use a polymer composed of an acidic compound and having a siloxane bond in the side chain, or a prepolymer or oligomer thereof. By using the above silicone polymer as a binder for the polishing layer, the abrasive grains can be uniformly applied without partial aggregation in the coating liquid or polishing layer, and suitable for ultra-fine polishing for precision parts Polishing sheet.

In order to cure the binder of the polishing layer, an organic metal compound such as a carboxylate such as zinc, cobalt, manganese, zirconium, lanthanum or tin, or an alkyl titanate such as tetrapropyl titanate or tetrabutyl titanate is added. It is preferable to prepare a coating liquid by using the above method. The amount of the curing agent is 0.0001 to 3.5 parts by weight, based on 100 parts by weight of the reactive resin contained in the binder. Is 0.1 to 0.5 parts by weight.

The weight ratio of the abrasive to the binder in the coating liquid is from 10:90 to 90:10, preferably from 25:75 to
75:25. When the ratio of the particles exceeds 90% by weight, the particles easily fall off. When the ratio is less than 10% by weight,
The grinding effect cannot be exhibited.

Abrasive grains having an average grain size of 100 to 300 μm
To disperse evenly with viscous varnish, for example,
Abrasive grains such as silica are isopropyl alcohol (IPA)
Wet in a solvent such as, or mixed with a non-ionic surfactant or an anionic surfactant added to adjust the coating solution, the above abrasive grains in the coating solution It can be dispersed uniformly. A preferred method is to thoroughly disperse the solvent by adding the solvent little by little to the abrasive grains which are wet and sufficiently dispersed in the solvent, further add the binder (varnish) dissolved in the solvent little by little, and stir until uniform. The purpose is to adjust a coating liquid having a good dispersion state by using sound waves.

The polishing layer formed by applying the coating liquid prepared as described above on the uneven surface provided on the base sheet has an uneven shape corresponding to the sheet. Therefore, the ferrule portion made of zirconia, which is harder than quartz, can be preferentially polished without greatly penetrating the optical fiber portion such as quartz in the polishing step. As a result, conventional polishing and polishing
The optical fiber portion which is ground to form a recess can also be processed into a flat or slightly convex shape.

The above-mentioned polishing layer contains 15 to 85% by weight, preferably 25 to 7% by weight of a nonvolatile component of the above-mentioned coating liquid for a polishing layer.
It is adjusted to 5% by weight, and the base sheet is uniformly coated by the gravure reverse coating method or the kiss reverse coating method up to the concave portion of the base sheet, and after the solvent is evaporated, the binder is dried and reacted. is there.

The polishing sheet can directly form a polishing layer on a base sheet made of a plastic film such as polyester having a thickness of 50 to 100 μm. If necessary, the adhesion between the polishing layer and the base sheet can be made strong and stable. For the purpose,
It is preferable to form the polishing layer after providing the primer on the substrate sheet.

The primer applied to the polishing sheet of the present invention varies depending on the type of the base sheet. However, acrylic primers such as vinyl chloride / vinyl acetate copolymers, polyvinyl acetal, polyalkyl acrylate and polyalkyl methacrylate can be used. Unstretched sheet containing a varnish containing a base resin or a copolymer thereof, an ethylene-based copolymer, a rubber-based derivative, a polyester, a polyamide, a phenol-based resin, an epoxy-based resin, an aminoplast, a polyurethane, and a cellulose derivative as a main component. Or after applying to a uniaxially stretched sheet, further applying a biaxial stretching process to strengthen the adhesive strength between the base material sheet and the primer, or simply applying to the stretched sheet to form it can.

The primer is applied to an unstretched sheet or a uniaxially stretched sheet and then stretched, whereby the primer is heat-welded to the sheet, and the adhesion between the base sheet and the primer can be strengthened. The primer can be formed not only by coating but also by stretching a co-extruded film. For example, polyethylene terephthalate and linear polyester (for example, when the secondary transition point Tg is 40 to 130)
Polyester) or polypropylene and ethylene-vinyl acetate copolymer, which have a different (lower) crystallization temperature than the resin used as the base sheet, are co-extruded with a resin used as a primer and then stretched. By doing so, a base sheet having good thickness accuracy and stable adhesion to the polishing layer can be formed.

The primer provided on the base sheet to firmly stabilize the adhesion between the polishing layer and the base sheet is not only a varnish made of the same kind of material as the binder but also has a slight tackiness as a primer. Even if it does, blocking can be prevented by applying in the same step as the polishing layer. Therefore, select a material that has an affinity for the base sheet and has a low glass transition point with a strong adhesive force. After coating the polishing layer, the primer and the polishing layer are simultaneously cured by heating or the like to reduce the blocking property of the primer. It can also be prevented. Depending on the type of these varnishes, the adhesion can be strengthened by adding a curing agent such as isocyanate.

As shown in FIG. 1, the coating liquid for a polishing sheet has a thickness of, for example, 10 to 200 μm, preferably 50 to 200 μm.
A primer 11 mainly composed of an epoxy resin, an acrylic resin, or polyester is provided on the base sheet 1 as required on the uneven surface 2 formed by the uneven shape of the polyethylene terephthalate sheet (base sheet 1) of about 100 μm.

Next, by a gravure reverse method using a gravure plate capable of uniformly and stably controlling the coating amount by a doctor action, 0.5 to 10 g / m ² (in the present specification, the coating amount is a solid content: g / m ² )), preferably 3.
A polishing layer having a turtle-shaped concave surface is formed by coating, drying and solidifying a polishing layer having a thickness of 10 to 10 g / m ² . In the binder of the present invention containing a siloxane bond, the curing reaction is accelerated by temperature and humidity. Therefore, the atmosphere at the time of coating is preferably as high as possible and high in humidity. However, when high temperature and high humidity become extreme, the coating liquid hardens on the gravure plate surface,
There are problems in that the curing reaction of the applied polishing layer becomes non-uniform, and that the coating liquid before coating undergoes a condensation reaction to generate a gel. Therefore, it is preferable that the relative humidity is 15 to 40 ° C. and the relative humidity at the same temperature is 30 to 60%.

The center line average roughness Ra of the polishing layer of the polishing sheet thus prepared is in the range of 0.1 to 0.5 μm, and has a turtle-shaped concave surface 6 shown in FIG. Therefore, it is suitable as a polishing layer for precision parts. In addition, a polishing sheet for precision parts can be formed which has no grinding flaws in the workpiece and has the ability to retain grinding dust and has improved durability in polishing the polishing sheet.

Although not shown, the polishing sheet of the present invention is mounted on a support made of a rotating metal plate via an elastic elastomer. In the polishing operation, for example, the end face of the optical connector ferrule excluding the optical fiber coating portion is polished on the polishing sheet at a revolution number of about 60 rpm for about 30 to 60 seconds. The polishing sheet of the present invention having a coated surface of abrasive grains such as silica and a concave portion of the polishing layer can be polished efficiently without causing a grinding flaw on the surface to be polished. Then, the worn polishing powder generated as the polishing layer is worn in the polishing process is sucked into the concave portion existing in the polishing layer, and the polishing layer is maintained in a state where the polishing powder is not present on the surface of the polishing layer. This prevents the occurrence of polishing unevenness in the above.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1) Tetron SM having a thickness of 75 μm
(Substrate sheet 1 A polyester film manufactured by Nippon Synthetic Rubber Co., Ltd.) on the uneven surface 2 of the uneven shape of the polyester film Teijin Ltd. After the application, a polishing layer having the following composition (coating solution 1) was applied at 5 g / m ² by a gravure reverse method and dried to obtain a polishing layer of Example 1 of the present invention.
A polishing sheet 10 was prepared. (Composition of coating liquid 1) ・ Glaska HPC7502 (polyorganosiloxane resin) 25 parts by weight (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) ・ IPA-ST (isopropanol silica sol) 75 parts by weight (average particle diameter of 10 to 20 μm) Nissan Chemical Industry Co., Ltd. product name)

(Example 2) Except that the base sheet 1 used in Example 1 was changed to a 75 μm-thick Tetron HPE (a polyester film made by Teijin Limited having irregularities formed by heating and embossing). The polishing sheet 5 of Example 2 of the present invention was provided with the polishing layer 5 in the same manner as in Example 1.
0 was created.

Example 3 A polishing layer was prepared in the same manner as in Example 1 except that the substrate layer 1 (Tetron SM) used in Example 1 was used and the polishing layer was changed to (Coating liquid 2). 5 was provided to prepare a polishing sheet 10 of Example 3 of the present invention. (Composition of coating liquid 2) ・ Glaska HPC7502 (polyorganosiloxane resin) 40 parts by weight (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) ・ Organosilica sol (isopropanol silica gel) 60 parts by weight (average particle size 70-100 μm Nissan) (Product name of Chemical Industry Co., Ltd.)

(Example 4) A polishing layer 5 was provided in the same manner as in Example 3 except that the base sheet 1 (Tetron HPE) of Example 2 was used to prepare the polishing sheet 10 of Example 4 of the present invention. Created.

Example 5 A polishing layer 5 was prepared in the same manner as in Example 1 except that the polishing layer was changed to (Coating liquid 3) using the base sheet 1 (Tetron SM) of Example 1. The polishing sheet 10 of Example 5 of the present invention was prepared. (Composition of coating liquid 3) ・ Glaska HPC7502 (polyorganosiloxane resin) 30 parts by weight (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) ・ Spherical silica Silica powder (average particle diameter 100 mμ) 70 parts by weight

Example 6 A polishing layer 5 was prepared in the same manner as in Example 5 except that the polishing layer was changed to (Coating liquid 4) using the base sheet 1 (Tetron HPE) of Example 2. The polishing sheet 10 of Example 6 of the present invention was prepared. (Composition of coating liquid 4) ・ Glaska HPC7502 (polyorganosiloxane resin) 30 parts by weight (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) ・ Aerosil OX50 silica powder 70 parts by weight (average particle size: 40 μm, manufactured by Degussa Co., Ltd.) Product name)

Example 7 Tetron S used in Example 1
No primer is provided on the uneven surface 2 of M (base sheet 1), the polishing layer is changed to (coating liquid 4), and 5 g / m ^{2 is} directly coated on the sheet by gravure reverse method and dried. Example 7 A polishing sheet 10 of Example 7 of the invention was made. (Composition of coating liquid 4) ・ Vironal MD-1245 (water-dispersed polyester resin) 30 parts by weight (trade name, manufactured by Toyobo Co., Ltd.) ・ Spherical silica (average particle diameter 100 mμ) 70 parts by weight ・ KBM1003 5 parts by weight (Silane coupling agent containing vinylmethoxysilane) (Shin-Etsu Chemical Co., Ltd. product name)

(Example 8) Using the base sheet 1 (Tetron HPE) used in Example 2, a primer layer was not provided on the uneven surface 2, and a polishing layer having the following composition was applied to (Coating liquid 5). Instead, directly apply 5 g / m ^{2 on the} sheet by the gravure reverse method.
Coating and drying were performed to prepare a polishing sheet 10 of Example 8 of the present invention. (Composition of coating liquid 5) ・ Vylonal MD-1245 (water-dispersed polyester resin) 30 parts by weight (trade name, manufactured by Toyobo Co., Ltd.) ・ Aerosil OX50 silica fine powder 70 parts by weight (average particle size 40 mμ Degussa Co., Ltd.) 5) parts by weight of KBM1003

(Example 9) In the same manner as in Example 7, a polishing layer having the following composition was changed to (Coating liquid 6), and 5 g / m ² was applied by a gravure reverse method and dried. Nine polishing sheets 10 were prepared. (Composition of coating liquid 6) ・ Vironal MD-1245 (water-dispersed polyester resin) 30 parts by weight (trade name, manufactured by Toyobo Co., Ltd.) ・ Snowtex 30 aqueous silica sol 70 parts by weight (average particle size: 10-20 μm Shin-Etsu (Product name of Chemical Industry Co., Ltd.)

Example 10 Using the same base sheet 1 as in Example 8, a coating liquid for a polishing layer having the following composition was applied (coating liquid 7).
A polishing sheet 10 of Example 10 of the present invention was made in the same manner as Example 9 except for changing the composition. (Composition of coating liquid 7) ・ Vironal MD-1245 (water-dispersed polyester resin) 30 parts by weight (trade name, manufactured by Toyobo Co., Ltd.) ・ Snowtex 30 aqueous silica sol 70 parts by weight (average particle diameter 10-20 μm Shin-Etsu (Product name of Chemical Industry Co., Ltd.)

Example 11 A polishing layer was formed by applying 5 g / m ² by a gravure reverse method and drying in the same manner as in Example 7 except that the polishing layer was changed to (Coating liquid 8). An abrasive sheet 11 of Example 11 of the present invention was produced. (Composition of coating liquid 8) ・ Vylonal MD-1245 (water-dispersed polyester resin) 30 parts by weight (trade name, manufactured by Toyobo Co., Ltd.) ・ Alumina sol 520 70 parts by weight aqueous silica sol (Average particle diameter: 10 to 20 μm) NISSAN CHEMICAL Industrial (product name)

Example 12 A polishing sheet 10 of Example 12 of the present invention was produced in the same manner as in Example 11 except that Tetron HPE was used as the base sheet 1 as in Example 8.

Example 13 Example 1 was repeated using Tetron SM except that the polishing layer having the following composition was changed to (Coating liquid 9).
In the same manner as in Example 1, 5 g / m ² (solid content) was applied by a gravure reverse method and dried to prepare a polishing sheet 10 of Example 13 of the present invention. (Composition of the coating liquid 9) 30 parts by weight of Vironal MD-1245 (water-dispersed polyester resin) (trade name, manufactured by Toyobo Co., Ltd.) 70 parts by weight of alumina powder (average particle size of 10 to 20 mμ Fujimi abrasive ( Co., Ltd.)

Example 14 Example 13 was the same as Example 12 except that the same base sheet 1 (Tetron HPE) was used.
In the same manner as in the above, a polishing sheet 10 of Example 14 of the present invention was prepared.

Comparative Example 1 Comparative Example 1 was performed in the same manner as in Example 1 except that (Tetron S) was used for the base sheet 1.
A polishing sheet was prepared.

Comparative Example 2 A polishing sheet of Comparative Example 2 was prepared in the same manner as in Example 7, except that (Tetron S) was used as the base sheet 1.

The center line average roughness Ra of each of the polishing sheets of the examples and the comparative examples was evaluated, and the end faces of the optical connector ferrules except for the coated portions of the optical fibers were used together with the respective polishing sheets. The polishing was performed for 60 seconds at the number of revolutions of, and the specularity, polishing scratches, presence or absence of polishing unevenness, work efficiency, the state of the step between the fiber ferrules, and the degree of damage (durability) of the polishing sheet were evaluated. The center line average roughness Ra of each of the examples and the comparative examples is 0.5 μm or less, and the evaluations of the comparative examples and others are as follows.

(Examples 1 and 2) Mirror finishing was performed with almost no deposits and no scratches or uneven spots. Improvement of work efficiency was recognized. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 3 and 4) There were almost no deposits, almost no polishing scratches and no polishing spots, and mirror finishing was possible. Improvement of work efficiency was recognized. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 5 and 6) Polishing scratches and polishing spots were extremely small, and mirror finishing with almost no deposits could be performed. Improvement of work efficiency was recognized. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 7, 8) Polishing scratches and polishing spots were very small, and mirror finishing with almost no deposits could be performed. A remarkable improvement in work efficiency was observed. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 9, 10) Polishing scratches and polishing spots were extremely small, and mirror finishing with almost no deposits was performed. A slight improvement in work efficiency was observed. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 11 and 12) Polishing scratches and spots were extremely small, and mirror finishing with almost no deposits could be performed. A slight improvement in working efficiency was observed. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Examples 13 and 14) Polishing scratches and spots were extremely small, and mirror finishing with almost no deposits could be performed. A slight improvement in working efficiency was observed. The step between the fiber ferrules could be processed to be smooth or slightly convex. (Comparative Examples 1 and 2) Polishing scratches and polishing spots were observed, and adhering substances and falling off of the polishing layer were observed, albeit slightly. No improvement in work efficiency could be recognized. The step between the fiber ferrules could not be processed into a convex shape.

[0050]

According to the present invention, the base sheet has an uneven shape, and
Since the polishing layer has a tortoise-shaped concave surface, the holding power of the abrasive grains at the convex portion is maintained during polishing, and the grinding effect is improved. Because there is space on the surface of the polishing layer to capture large grinding debris,
The end surface of the optical fiber, the optical lens, and the mirror finish, which is the final finish of the surface of the semiconductor wafer, are reduced in generation of scratches and deposits due to grinding dust, and improvement in grinding efficiency is recognized. Also, the abrasive grains dispersed in the polishing layer are formed from those having a size of 10 to 200 mμ, and have a uniform size, 100 to 800 m.
μ, and no coarse particles of 5 to 10 μm are present. Therefore, the end face of the optical fiber,
Optical lens, mirror finish which is the final finish of semiconductor wafer surface, etc.
Further, there is an effect of polishing that can be performed without a step between the fiber ferrules. And since the base material sheet is processed into irregularities, the surface of the polishing layer does not bite into the optical fiber made of quartz, and the ferrule made of zirconia harder than quartz can be ground. As a result, there is an effect that the fiber portion which is largely ground and dented can be processed into a flat shape or a slightly convex shape. In addition, since the polishing layer formed by providing the primer has firm and stable adhesion, the abrasive grains do not fall off during the polishing step. Therefore, not only can a mirror surface be formed by high-speed rotation polishing, but also an effect that a polishing sheet excellent in durability can be provided can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a polishing sheet of the present invention.

FIG. 2 is a schematic plan view of a polishing sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base sheet 2 Uneven surface of base sheet 3 Binder 4 Abrasive grain 5 Polishing layer 6 Concave face of turtle shape 10 Polishing sheet 11 Primer

Claims (5)

[Claims] 1. A polishing sheet having a polishing layer on an uneven surface of a base sheet having an uneven shape on the surface, wherein an average particle diameter of abrasive grains contained in the polishing layer is 100 to 800 mμ. Polishing sheet. 2. The surface of the polishing layer according to claim 1,
A polishing sheet characterized by having a center line average roughness Ra of 0.1 to 0.5 μm and having a turtle-shaped concave surface. 3. The abrasive grains forming the polishing layer are silica particles, and the binder is a polyorganosiloxane;
The polishing sheet according to claim 1, wherein the polishing sheet is a resin varnish containing a silane coupling agent having a vinyl group or an epoxy group. 4. The polishing sheet according to claim 1, wherein the substrate sheet having an uneven surface forming the polishing layer is a polyester film. 5. A polishing sheet having a polishing layer on an uneven surface of a substrate sheet having an uneven surface, wherein the abrasive particles contained in the polishing layer have a particle diameter of 100 to 800 μm. A primer is provided on the uneven surface of the material sheet,
Further, the average particle diameter of the abrasive grains is 10 to 200 mμ silica particles, and the coating liquid is a resin varnish containing a polyorganosiloxane binder, or a silane coupling agent having a vinyl group or an epoxy group. 5. The method for producing a polishing sheet according to claim 1, wherein the polishing layer is formed.