JPH10277957A - Polishing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing film which requires no polishing agent, and can manufacture an optical fiber connector part excellent in optical, characteristics. SOLUTION: A first polishing layer 2 is formed over a supporting body 1 such as a plastic film and the like, in which a polishing agent composed of silica perticulates is dispersed over water insoluble resin, and a second polishing layer 3 is formed over the second polishing layer, in which a polishing agent composed of silica perticulates that are smaller in grain size than the polishing agent used by the first polishing layer, is dispersed over water soluble resin. This polishing film 10 is suitably used as a final finishing film for polishing an optical connector part, enables both ferrules and quartz fibers to be simultaneously polished, and thereby to be formed into a mirror surface, can prevent the occurrence of the difference in level between each ferrule and each quartz fiber, and also prevents a work deterioration layer different in index of refraction from being formed up over the surface of quartz fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing film for polishing an optical fiber connector, and more particularly to a polishing film which does not require a polishing liquid containing an abrasive.

[0002]

2. Description of the Related Art Optical fiber connectors are used for connecting and disconnecting optical fibers. Usually, a glass fiber is fixed to the center of a ferrule made of zirconia or the like, and the end surface thereof is polished to a mirror surface. I have. Since the glass fiber is connected to another glass fiber at this end face, it must be precisely polished so as to minimize communication loss at the connection end face. In particular, it is important that there is no step between the ferrule and the glass fiber, and that the end face of the glass fiber has no damaged layer due to polishing.

Conventionally, as a method of polishing an optical fiber connector portion, after a primary polishing is performed with a hard abrasive such as diamond, a polishing liquid containing an abrasive is applied to the film while the connector portion is pressed against the film and the connector portion. There is known a method in which an optical fiber is rotated while being supplied between the substrates and polished (JP-A-62-173159, JP-A-3-817).
08).

As a final finish, a method of mirror-finishing only a quartz fiber using a polishing film provided with a polishing layer containing a polishing agent such as cerium oxide, alumina, zirconia, and chromium oxide is generally performed. . As such a polishing film, there has been proposed a film provided with a layer in which an abrasive is contained in a resin on a base material (Japanese Patent Laid-Open No. 8-33).
No. 6758).

[0005]

However, in the conventional polishing method using the above-mentioned polishing liquid in which the polishing liquid is dispersed, the concentration of the polishing liquid in the polishing liquid changes during polishing.
In addition, there is a problem that it is difficult to always supply an abrasive with a uniform concentration between the connector portion and the film,
Further, in a low temperature environment (below the freezing point) such as a cold region, there is a problem that the abrasive particles in the solvent are crystallized and cannot exhibit their original performance.

As a polishing sheet for a magnetic disk or the like, a polishing sheet having a polishing layer made of polishing particles and a water-soluble binder adhesive provided on a non-woven fabric has been proposed (JP-A-7-1007).
No. 69), in the polishing step using this polishing sheet, a polishing liquid containing an abrasive is not required, and it is possible to facilitate automated mass polishing. However, such a polishing sheet cannot perform high-precision polishing required for a final polishing step of an optical fiber.

[0007] Further, there is no conventional polishing film capable of simultaneously polishing a ferrule and a quartz fiber to produce a mirror surface. Therefore, in the final finish using the conventional polishing film, only the quartz fiber is polished. ,
A concave portion is formed between the ferrule and the quartz fiber, and an air layer is formed at the connection portion, thereby causing a communication loss. Further, when the final polishing is performed with a conventional polishing film, although a mirror surface is obtained, a damaged layer is formed on the surface of the quartz fiber, and there is a problem that the refractive index of the quartz fiber changes in the damaged layer. Generally, as the optical characteristics of the optical fiber connector, the return loss is required to be 50 dB or more in the case of right-angle spherical polishing (PC polishing) and 60 dB or more in the case of oblique spherical polishing (APC polishing).
In the case of a quartz fiber with a deteriorated layer, the return loss is 40
It was about dB.

Accordingly, an object of the present invention is to provide a polishing film that can eliminate the need for a polishing liquid in which a polishing agent is dispersed and that can perform high-precision polishing for final polishing of an optical fiber. I do. Another object of the present invention is to provide a polishing film for polishing an optical fiber connector portion, which can obtain an optical fiber connector having no difference in level with a ferrule and having an extremely small return loss and excellent optical characteristics.

[0009]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies on the combination of an abrasive and a binder resin. When a water-soluble resin is used as the resin, the upper layer abrasive is released by supplying purified water, and uniform polishing can be performed without using a polishing liquid, and the lower layer abrasive is used as the upper layer abrasive. The present inventors have found that it is possible to perform polishing with extremely high precision by using an abrasive having a smaller particle size than the present invention, and have reached the present invention.

That is, the polishing film of the present invention is formed on a support, and includes a first polishing layer containing a water-insoluble resin and an abrasive dispersed in the water-insoluble resin, and a first polishing layer formed on the first polishing layer. And a second polishing layer containing a water-soluble resin and an abrasive dispersed in the water-soluble resin, and preferably the average particle diameter of the abrasive contained in the second polishing layer is: First
Is smaller than the average particle size of the abrasive contained in the polishing layer.

As the polishing agent for the first polishing layer and the polishing agent for the second polishing layer, the same type, particularly silica fine particles, is preferably used. Since the silica fine particles have a slight polishing power not only for quartz but also for zirconia ceramics, it is possible to polish the ferrule and the quartz fiber at the same time by using this, and furthermore, the refractive index of the surface after polishing is reduced to quartz. Since the refractive index is almost the same as that of the fiber, the return loss at the end face can be reduced, and the noise of the optical signal and the adverse effect on the semiconductor light source can be minimized.

The water-soluble resin used for the second polishing layer is polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose resin, water-soluble polyester resin, polyvinyl acetal, acrylic acid-acrylamide copolymer, melamine resin, polyether polyol. 1 selected from, gelatin, casein, starch, chitin, chitosan
Species or two or more are preferred.

The abrasive for the second polishing layer is contained in a weight ratio of 1: 5 to 5: 1 with respect to the water-soluble resin.

[0014]

FIG. 1 is a view showing one embodiment of a polishing film of the present invention. The polishing film comprises a support 1, a first polishing layer 2 formed thereon, and And the second polishing layer 3 formed on the substrate.

The second polishing layer is a layer in which the end face of the optical fiber, which is the material to be polished, is brought into direct contact, and is composed of a water-soluble resin and an abrasive. When the polishing layer is polished by supplying water (purified water) between the polishing layer and the end face of the optical fiber, the polishing agent can be released from the water-soluble resin and polished.

The water-soluble resin is preferably of a low viscosity so that the abrasive can be released immediately during polishing. Examples of such a water-soluble resin include polyvinyl alcohol, polyvinyl pyrrolidone, a water-soluble cellulose resin, a water-soluble polyester resin, polyvinyl acetal, an acrylic acid-acrylamide copolymer, a melamine resin, a synthetic resin such as a polyether polyol, gelatin, and casein. , Starch, chitin, chitosan and the like. These resins can be used alone or in combination of two or more.

As the polishing agent, known polishing agents such as silica, alumina, cerium oxide, and aluminum oxide can be used. When the optical fiber to be polished is a quartz fiber, silica is preferable. Particularly, crystalline or non-crystalline silica having a silanol group on the surface is preferable. In general, when the end face of an optical fiber is polished with an abrasive, a damaged layer is formed on the surface, and the difference in refractive index between the damaged layer and the optical fiber core causes an increase in return loss and causes communication loss. However, when silica is used as the polishing agent, the formation of a damaged layer on the quartz surface is suppressed, and the change in the refractive index at the end face can be extremely reduced.

When the polishing film of the present invention is not used for the purpose of final polishing or when a plastic fiber is used as an optical fiber, the abrasive is not limited to silica.

It is necessary that the average particle size of the abrasive is smaller than the average particle size of the abrasive in the lower polishing layer 2. It is considered that good polishing performance can be obtained by providing a layer of fine abrasive on a layer of abrasive having a relatively large particle size. As described above, the average particle size of the abrasive in the polishing layer 3 is determined by the relationship with the average particle size of the abrasive in the polishing layer 2,
The polishing film of the present invention varies depending on the stage of polishing, but in the case of a polishing film for final polishing, the thickness is preferably in the range of 1 nm to 1 μm, more preferably 1 to 100 nm. In order to perform uniform polishing, it is preferable to use a material having a narrow particle size distribution as much as possible.

The content ratio of the water-soluble resin and the abrasive is 5: 1.
１ ： 1: 5 is preferred, and 3: 1 to 1: 3 is more preferred. If the ratio of the abrasive is less than 5: 1, a sufficient polishing effect cannot be obtained. If the ratio of the abrasive is more than 1: 5, it cannot be held in the resin, and it becomes difficult to form a layer.

The first polishing layer 2 is made of the second polishing layer 3 described above.
The lower layer is composed of a water-insoluble resin and an abrasive. Water-insoluble resins include acrylic resins, ethylene-vinyl acetate copolymers, polyvinyl butyral resins, silicone resins, thermoplastic polyester resins, polystyrene resins, vinyl chloride-vinyl acetate copolymers, cellulose derivative resins, and crosslinkable polyester polyols And a crosslinkable acrylic polyol, and the like, and a polyester polyol and an acrylic polyol crosslinked with isocyanate are particularly preferable. These crosslinkable resins have excellent hardness and flexibility as a polishing layer, and also have good adhesion to a support. The crosslinkable resin can be used alone or in combination with another water-insoluble resin.

As the polishing agent for the first polishing layer 2, the same polishing agent as that used for the second polishing layer 3 can be used, particularly when the optical fiber to be polished is a quartz fiber. Is preferably silica. The average particle size is
Of the polishing layer 3 having a larger average particle size than the polishing agent. When the polishing film of the present invention is used for final polishing, specifically, 1 μm to 10 μm is suitable. When the average particle size is smaller than 1 μm, the polishing ability is reduced. On the other hand, if it is larger than 10 μm, it may cause scratches on the surface to be polished.

The content ratio of the water-insoluble resin to the abrasive is 5:
1-1 to 1: 5 is preferred. If the ratio of the abrasive is less than 5: 1, a sufficient polishing effect cannot be obtained.
If the ratio of the abrasive is more than 1: 5, it cannot be held in the resin, and it becomes difficult to form a layer.

As the support 1, synthetic paper or plastic film having mechanical strength and dimensional stability capable of withstanding the pressure during polishing can be used. In particular, polyethylene terephthalate, polyethylene, polyvinyl chloride, polyvinylidene chloride, Plastic films such as polycarbonate, polystyrene, polyacrylonitrile, ABS, nylon, and polypropylene are preferably used. An anchor layer may be provided on the support 1 in order to increase the adhesion of the first polishing layer 2.

The polishing film of the present invention is applied with a coating solution containing a water-insoluble resin and an abrasive which constitute the first polishing layer 2 on the support 1 described above, and then dried to obtain a first polishing film. After the polishing layer 2 is formed, a coating liquid containing a water-insoluble resin and an abrasive, which constitute the second polishing layer 3, is applied thereon, followed by drying. In addition to the above-mentioned materials, a leveling agent, a dispersant, an oxidizing agent, an antistatic agent, a fungicide, and the like can be added to the first and second polishing layers as needed.

The thickness of the first polishing layer 2 is 1 to 20 μm,
Preferably, it is 3 to 10 μm. The thickness of the polishing layer 2 is 1 μm
If the amount is smaller, a sufficient polishing effect cannot be obtained. The thickness of the second polishing layer 3 is 1 to 30 μm, preferably 3 to 20 μm.
μm. If the thickness of the polishing layer 3 is less than 1 μm, good polishing characteristics cannot be obtained as final polishing. On the other hand, if the thickness is more than 30 μm, it is not preferable because warpage of the polishing film, that is, curling property occurs.

The polishing film of the present invention is used for polishing after the second polishing of the optical fiber connector portion which has been subjected to the first polishing using a polishing agent such as diamond or the like, and is preferably used for final finishing. Used as For example, as shown in FIG. 2, the polishing film 10 is fixed on a polishing pad 20 of a polishing machine, and purified water is sprayed on the surface of the second polishing layer 3, and an optical fiber connector is mounted on a polishing holder (not shown). After the part 30 is fixed, the connector part 30 is brought into contact with the polishing film 10 at a constant pressure, so that the polishing pad 2
The connector portion 30 is polished by rotating the polishing holder 0 or the polishing holder. As a result, the abrasive (silica fine particles) dispersed in the second polishing layer 3 is released, and the quartz fiber of the optical fiber connector 30 is mirror-polished. At this time, the zirconia of the ferrule is also polished to prevent a concave portion from being formed in the quartz fiber portion.

In general, in the optical fiber connector portion, when the curvature of the tip of the ferrule is in the range of 10 to 25 mm, the dent amount ± 0.05 μm is regarded as an allowable limit for obtaining good optical characteristics. However, the polishing film of the present invention is used. By doing
The dent amount can be within an allowable value. When the optical fiber connector is polished by using the polishing film of the present invention, the return loss at the connection surface can be set to 50 dB or more.

[0029]

Examples of the present invention will be described below. Example 1 A coating liquid for a polishing layer having the following formulation was applied to one surface of a polyester film having a thickness of 75 μm and dried to form a polishing layer (first polishing layer) having a thickness of 6 μm. The surface roughness Ra of this polishing layer was 0.7 μm.

First polishing layer coating liquid Acrylic polyol 44 parts by weight (Acrylic A804, solid content 50%: Dainippon Ink and Chemicals, Inc.) Nitrocellulose 17 parts by weight (L1 / 2: solid content 70%) Silica 25 Parts by weight (Sylysia 730, particle size 3.0 μm: Fuji Silysia Chemical Ltd.) Isocyanate curing agent 14 parts by weight (Takenate D110N, solid content 60%: Takeda Pharmaceutical Co., Ltd.) Methyl ethyl ketone 200 parts by weight Toluene 200 parts by weight

Next, a second polishing layer coating solution having the following formulation was applied on the first polishing layer and dried to form a second polishing layer having a dry thickness of 10 μm, thereby producing a polishing film. 5 parts by weight of polyvinyl alcohol (Co-Senol GL-03: Nippon Gohsei) 5 parts by weight of silica (Aerosil 200, particle size 12 nm: Aerosil Nippon) 40 parts by weight of water

The polishing film (φ12
7 mm), an optical connector ferrule of quartz fiber was finally polished by an optical connector polishing machine (SFP-120A: manufactured by Seiko Giken Co., Ltd.). Polishing is performed using the optical connector ferrule 12 described above.
The book was mounted on a polishing holder of a polishing machine, and 3-5 cc of purified water was supplied onto the polishing film, and the final polishing time was 30 seconds. With respect to the polished connector portion, the concave amount of the quartz fiber was evaluated from the specularity, return loss, curvature and ferrule. The specularity was observed with an optical microscope (magnification: 200). The return loss was evaluated with a light meter (JISFITEL: RM3750B). The curvature and the dent amount were evaluated by an automatic connect check interference system (Axis: NTTAT).

As a result of observation with an optical microscope, this polished film simultaneously polished the zirconia ferrule and the quartz fiber to create a mirror surface, so that no dent as in the prior art was seen, and the measurement result of the automatic connect check interference system was used. However, the dent amount was -0.01 µm on average for the curvature of 11 mm to 16 mm. The return loss is also 56d on average
B.

[0034]

As is clear from the above examples, the polishing film of the present invention comprises a water-soluble resin and an abrasive having a finer particle size than the abrasive of the first abrasive layer, on the first abrasive layer. Since the ferrule and the glass fiber can be polished at the same time since the second polishing layer including the second polishing layer is included, excellent polishing performance can be achieved without generating a step between the ferrule and the glass bar fiber. Have. In particular, by using silica as an abrasive, the formation of a deteriorated layer can be suppressed, the return loss can be greatly improved, and an optical fiber connector having excellent optical characteristics can be manufactured. In addition, the polishing film of the present invention can be used in a low-temperature environment by eliminating the need for a polishing solution containing a polishing agent by forming the second polishing layer, which is the uppermost layer, with a water-soluble resin and a polishing agent. Polishing characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a polishing film of the present invention.

FIG. 2 is a diagram illustrating a method of using the polishing film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support 2 ... 1st polishing layer 3 ... 2nd polishing layer

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kiyoshi Kurumada 286 Matsushitadai, Matsudo-shi, Chiba 23 Seiko Giken Co., Ltd.

Claims (5)

[Claims] A first polishing layer formed on a support and containing a water-insoluble resin and an abrasive dispersed in the water-insoluble resin; and a water-soluble resin formed on the first polishing layer. And a second polishing layer containing an abrasive dispersed in the water-soluble resin. 2. The method according to claim 1, wherein the average particle size of the abrasive contained in the second polishing layer is smaller than the average particle size of the abrasive contained in the first polishing layer. Polishing film. 3. An abrasive for said first polishing layer and said second polishing agent.
2. The polishing film according to claim 1, wherein the polishing agent of said polishing layer comprises silica fine particles. 4. The water-soluble resin is polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose resin, water-soluble polyester resin, polyvinyl acetal, acrylic acid-acrylamide copolymer, melamine resin, polyether polyol, gelatin, casein, starch. 2. The polishing film according to claim 1, wherein the polishing film is at least one member selected from the group consisting of chitin, chitin, and chitosan. 5. The polishing film according to claim 1, wherein the abrasive of said second polishing layer is contained in a weight ratio of 1: 5 to 5: 1 with respect to said water-soluble resin. .