JP2010274348A - Polishing film and polishing method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing film capable of suppressing generation of scratches and performing finish polishing with high smoothness, and also to provide a polishing method using the same. <P>SOLUTION: The polishing film includes a base material film 11 to be the base material of the polishing film 10a and a polishing layer 15a formed on the base material film 11. The polishing layer 15a contains polishing particles 12 and a binder resin 14 for sticking the polishing particles 12. The binder resin 14 is a water-soluble binder resin 14. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a polishing film and a polishing method using the same, and more specifically to a polishing film suitable for finish polishing of an end face of an optical fiber connection portion of a fiber optic connector, a semiconductor substrate and the like, and a polishing method using the polishing film. Is.

  An optical fiber connector is a member that connects an optical fiber and an optical fiber. The periphery of the connection portion of the optical fiber is covered with zirconia called a ferrule, and the end surface of the connection portion (hereinafter referred to as “connection portion end surface”) is mirror-finished. The connection part end faces are butted together and connected.

  The mirror processing of the end face of the connection portion of the optical fiber connector is performed by a plurality of stages of polishing from rough polishing to final finish polishing in which the particle size of the abrasive is sequentially reduced.

  Optical fibers pass through the core located at the center of the optical fiber, so when connecting optical fibers, it is necessary to improve the processing accuracy of the end face of the connection. Especially, the processing accuracy of the final finish polishing directly affects the optical characteristics. Effect.

  Therefore, the end surface of the connection portion of the optical fiber needs to be subjected to surface finish polishing so that the end portion of the optical fiber does not protrude from the end surface of the connection portion by 100 nm or more or is recessed by 50 nm or more in the final finish polishing. Further, depending on the application, there is also a demand for the end of the optical fiber to be ± 50 nm or less with respect to the end face of the connection part.

  If the end of the optical fiber is scratched, a dent is formed at the boundary between the optical fiber and the ferrule, or if the end of the optical fiber is excessively polished and deformed, light scattering occurs at the end of the optical fiber. However, the transmission characteristics of the entire communication system are not as designed. Therefore, high smoothness and processing accuracy are required for the end face of the connection portion of the optical fiber.

  Conventionally, the end face of the connecting portion of the optical fiber has been polished into a convex spherical surface in order to reduce loss and reflected return light on the connecting surface. As this polishing technique, a method of polishing with a fixed abrasive polishing sheet or a plastic sheet There has been proposed a method in which a free abrasive liquid is supplied and polished.

  For example, a certain tension is applied to a cellulosic resin film that does not contain an abrasive, and the surface of the resin film is slid while pressing the tip of the ferrule of the optical connector, while the silica-based polishing is applied to the contact portion. A method of polishing by supplying a polishing liquid having a material has been proposed (see Patent Documents 1 and 2).

  However, in the polishing method as described above, due to the difference in polishing characteristics due to the difference in material between the ferrule of ceramic material (zirconia) and the optical fiber of glass material, in order to polish the end surface of the connecting portion to a convex spherical surface However, the management of maintaining polishing conditions such as uniform supply of loose abrasive grains becomes complicated, and there is a difficult surface for polishing to form a convex spherical surface. Further, since the supplied abrasive particles escape without being fixed on the resin film surface, there is a problem that the polishing force is not exhibited.

  As another finish polishing technique, a polishing method using a polishing medium (fixed abrasive sheet) having a polishing layer containing abrasive particles such as alumina and silica without using a polishing liquid has been proposed (patent) References 3 and 4). By polishing the end face of the connecting portion by this polishing method, the problems caused by the use of the polishing liquid are eliminated.

  However, in the above method, during the polishing of the end face of the connecting portion of the optical fiber, the optical fiber or ferrule polishing scraps generated by the polishing and the falling particles of the polishing layer are interposed, so that the end face of the optical fiber or ferrule is scratched (scratch). ) Occurs, which adversely affects the optical characteristics of the connection end face after polishing.

  In order to cope with the above problem, in the polishing medium (fixed particle polishing sheet), a strong binder material is used so that the abrasive grains do not fall off from the binder. Separation of the binder resin occurs, resulting in a problem that scratches increase and the optical fiber portion is also recessed from the connection end surface.

JP-A-3-81708 Japanese Patent Laid-Open No. 4-100008 JP-A-8-336758 JP 2002-192472 A

  The present invention provides a polishing film capable of suppressing the occurrence of scratches on the polishing surface and capable of highly smooth polishing in finish polishing of an object to be polished such as an end surface of an optical fiber connection portion of an optical fiber connector, and a polishing method using the same. With the goal.

  In order to solve the above problems, the present invention provides a substrate film that is a substrate of an abrasive film, and an abrasive layer formed on the substrate film, the abrasive layer comprising abrasive particles and And a binder resin for fixing the abrasive particles, wherein the binder resin is a water-soluble binder resin.

  As described above, since the binder resin for fixing the abrasive particles is a water-soluble binder resin, if the polishing layer is dropped and polished with an aqueous solution containing a certain amount of water or a lubricant, the polishing layer is polished during polishing. A part of the binder resin on the surface is dissolved, and the abrasive particles of the dissolved part act as free abrasive grains. In particular, in the portion where the object to be polished and the polishing layer are pressed during polishing, the binder resin is gradually dissolved by the pressing pressure, so that free abrasive grains are always supplied during polishing, and fixed abrasive grains and In addition, it can contribute to polishing.

  When the polishing film is used in polishing the end face of the optical fiber connection portion, the abrasive particles are fluidly present on the end face of the optical fiber. Smooth finish polishing in which the portion is within an allowable step (for example, ± 50 nm or less) becomes possible.

  As the water-soluble binder resin, a water-soluble polymer material and a water-soluble cellulose resin are used. In particular, the water-soluble binder resin preferably includes a partially saponified polyvinyl alcohol having a saponification degree in the range of 85 mol% to 97 mol%. Further, the water-soluble binder resin is preferably composed of a partially saponified polyvinyl alcohol having a saponification degree of 85 mol% to 97 mol% or a main component.

  In the case of partially saponified polyvinyl alcohol having a saponification degree in the above range, the binder on the surface of the polishing layer was gradually dissolved during polishing, and the abrasive particles released by this dissolution were fixed to the polishing layer. The polishing surface can be uniformly polished with the abrasive particles.

  The polishing layer preferably further comprises a glycol compound. By adding a glycol-based compound to the polishing layer, the lubricating action is increased, which is effective in reducing fine scratches.

  The abrasive particles are preferably colloidal silica particles having an average particle diameter in the range of 10 nm to 30 nm, and the amount thereof is preferably in the range of 80 wt% to 98 wt% with respect to the polishing layer.

  The abrasive particles are colloidal silica particles having an average particle size in the range of 10 nm to 30 nm, and the polishing layer further includes spherical auxiliary particles in the range of an average particle size of 70 nm to 150 nm, and the colloidal The weight ratio between the silica particles and the spherical auxiliary particles is preferably in the range of 90:10 to 70:30, and the total amount of the colloidal silica particles and the spherical auxiliary particles is in the polishing layer. It is preferably in the range of 80% by weight to 98% by weight.

  The present invention further provides a polishing method using the above-described polishing film, wherein the surface of the object to be polished is pressed against the polishing layer of the polishing film fixed on the polishing disk of the polishing apparatus. The first step, the polishing disk to which the polishing film is fixed, and the surface of the object to be polished pressed by the polishing layer are moved relative to each other while maintaining the pressed state for polishing. And a second step, wherein in the second step, a predetermined amount of water or an aqueous solution containing a lubricant is dropped on the surface of the polishing layer in advance.

  As described above, after a predetermined amount of water or an aqueous solution containing a lubricant is dropped on the surface of the polishing layer in advance, the surface of the object pressed against the polishing layer is relatively maintained while maintaining the pressed state. Since the abrasive particles released from the polishing layer are always present on the polishing surface due to dissolution of the water-soluble binder resin, the occurrence of slats on the polishing surface can be suppressed and smooth polishing can be achieved.

  In the second step, the polishing disc may be a rotational motion that includes a rotational motion and a revolving motion.

  Further, the surface of the object to be polished can be an end face of an optical fiber connection part in an optical fiber connector. The polishing method is suitable for polishing the end face of the optical fiber connection portion that requires smooth finish polishing while suppressing the occurrence of scratches.

  ADVANTAGE OF THE INVENTION According to this invention, finish polishing with high smoothness which suppressed generation | occurrence | production of the scratch in the grinding | polishing surface of a grinding | polishing body is attained.

  In particular, it is possible to suppress the generation of scratches in the finish polishing of the connection portion end face of the optical fiber connector, and to make the connection portion end face a step within an allowable range.

Fig.1 (a) is a cross-sectional schematic diagram of 1st Embodiment of the abrasive film which concerns on this invention, FIG.1 (b) is a cross-sectional schematic diagram of 2nd Embodiment of the abrasive film which concerns on this invention. FIG. 2 is a schematic view of an optical fiber connection portion polished by the polishing method of the present invention, FIG. 2 (a) is a schematic sectional view of the optical fiber connection portion, and FIG. 2 (b) is an optical fiber connection portion end face. It is a front schematic diagram, and is an AA arrow line view of Fig.2 (a). FIG. 3 is a schematic sectional view of a polishing apparatus used in the polishing method of the present invention. FIG. 4 is a schematic view showing an embodiment of a method for polishing an end face of an optical fiber connection part of an optical fiber connector using the polishing film according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
<Polished film>
As shown in FIG. 1A, the polishing film 10a according to the first embodiment of the present invention includes a base film 11 serving as a base and a polishing layer 15a formed on the base film. . The abrasive layer 15 a is formed of abrasive particles 12 and a water-soluble binder resin 14 that fixes the abrasive particles 12 to the abrasive layer 15 and is soluble in water. Further, cracks 16 having a triangular cross section having a pitch of 10 μm to 200 μm are formed on the surface of the polishing layer 15 a like a mesh. The cracks 16 are provided for taking up polishing scraps.

  As shown in FIG. 1B, the polishing film 10 b according to the second embodiment of the present invention has spherical auxiliary particles 13 in which the polishing layer 15 b has a larger particle diameter than the polishing particles 12 in addition to the polishing particles 12. It becomes the composition which added. The polishing film 10b is different from the polishing film 10a in that the spherical auxiliary particles 13 are added.

  The abrasive particles 12 directly contribute to the polishing of the polishing surface of the object to be polished. On the other hand, the spherical auxiliary particles 13 have a particle diameter larger than that of the polishing particles 12 and reduce the frictional resistance to the polishing surface. The spherical auxiliary particles 13 also have a role as a spacer for maintaining the space between the object to be polished and the polishing film 10b. . It is necessary to make the amount smaller than that of the abrasive particles 12 so that these roles can function and the function of the abrasive particles 12 is not impaired.

  Further, it is understood that by interposing an appropriate amount of spherical auxiliary particles 13 having a large particle diameter, the adhesive strength between the abrasive particles 12 and spherical auxiliary particles 13 and the binder resin 14 is improved, and the durability of the polishing layer 15b is improved. The The spherical auxiliary particles 13 are preferably spherical in shape in order to prevent the occurrence of scratches on the polished surface of the object to be polished.

  As described above, the difference between the polishing film 10a of the first embodiment and the polishing film 10b of the second embodiment is only the presence or absence of the spherical auxiliary particles 13, and while appropriately adding explanation of the difference, Common items are described below.

  The base film 11 of the polishing films 10a and 10b is a plastic film made of synthetic resin having flexibility. As a plastic film made of synthetic resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefin resin such as polyethylene and polypropylene, polystyrene, polyvinyl chloride, polyvinyl alcohol or methacryl alcohol are the main components. Examples thereof include a film made of acrylic resin, polycarbonate, and the like.

  Among these, practically, it is preferable to use polyethylene terephthalate as the base film 11 because the film for manufacturing the abrasive film is easy to handle.

  In addition, by using the base film 11 that has been previously primed on the surface, peeling between the base film 11 and the polishing layers 15a and 15b can be prevented, and the durability of the polishing layers 15a and 15b is also improved. improves.

  The thickness of the base film 11 is not particularly limited, but is in the range of 5 μm to 100 μm, and preferably in the range of 10 μm to 75 μm.

  As the abrasive particles 12 of the abrasive films 10a and 10b, fine particles such as silica, alumina and diamond are used. In particular, it is preferable to use spherical silica particles (colloidal silica) as the abrasive particles 12 for polishing the end face of the connection portion of the optical fiber. In particular, colloidal silica particles having an average particle diameter of 10 nm to 30 nm are used. When the average particle diameter is less than 10 nm, not only the polishing power is reduced, but also the binder resin and the adhered particles of the abrasive particles remain on the polished surface such as the end surface of the connection portion of the optical fiber. Because. Further, when the average particle diameter is 30 nm or more, scratches generated on the polished surface increase.

  As long as the average particle diameter is in the range of 10 nm to 30 nm, the abrasive particles 12 may be one type or may be a mixture of two types in an appropriate ratio.

  In addition to the abrasive particles 12, spherical auxiliary particles 13 having an average particle diameter of 70 nm to 150 nm are fixed to the abrasive layer 15b of the abrasive film 10b of the second embodiment. When the spherical auxiliary particle 13 is less than 70 nm, it acts as an abrasive particle, and the scratch on the polished surface tends to increase, and when it exceeds 150 nm, the deep scratch on the polished surface tends to increase.

  The weight ratio between the abrasive particles 12 and the spherical auxiliary particles 13 is preferably in the range of 90:10 to 70:30. When the weight ratio of the abrasive particles 12 to the spherical auxiliary particles 13 is less than 90:10, the frictional resistance against the polished surface increases, the amount of deposits on the polished surface increases after polishing, and the durability of the polishing layer also deteriorates. . On the other hand, when the weight ratio exceeds 70:30, scratches on the polishing surface increase, and when the object to be polished is the end face of the optical fiber connection, the recess of the end of the optical fiber on the end face of the connection becomes large.

  The spherical auxiliary particles 13 may be spherical resin particles made of acrylic, polyester, or urethane, instead of colloidal silica.

  As the abrasive particles 12 and the spherical auxiliary particles 13, particles dispersed in a dispersion such as alcohols or methyl ethyl ketone are used. As the dispersion, for example, a dispersion obtained by dispersing 20 to 40% by weight of the abrasive particles 12 and the spherical auxiliary particles 13 in isopropyl alcohol (IPA) in advance is used.

  Examples of the binder resin for the polishing layers 15a and 15b include water-soluble polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, polyethylene oxide, and hyaluronic acid.

  Among the above binder resins, those that satisfy the condition that the object to be polished and the polishing layer are gradually dissolved from the surface in contact with the pressing pressure, rather than being dissolved at once by water after being cured, are preferable. As a binder resin that satisfies this condition, polyvinyl alcohol is preferred.

  The water-soluble polyvinyl alcohol is obtained by polymerizing vinyl acetate and saponifying the polyvinyl acetate. The saponification step is a reaction in which the acetate group of polyvinyl acetate is substituted with a hydroxyl group in a methanol solvent using an alkali catalyst to form polyvinyl alcohol. In this step, the saponification degree is determined by adjusting the amount of hydroxyl groups. The degree of saponification is the ratio (mol%) of the quantity of hydroxyl groups to the degree of polymerization, which is the total quantity of hydroxyl groups and acetate groups. The solubility of polyvinyl alcohol in water is mainly determined by the degree of saponification and the degree of polymerization.

  The saponification degree of polyvinyl alcohol used as the binder resin 14 is preferably in the range of 85 to 97 mol%. The estimated degree of polymerization is in the range of 1700-2550. When the degree of saponification is less than 85 mol%, the polishing layer becomes soft, and in polishing of the end face of the connection portion of the optical fiber, the surface of the polishing layer bites into the end portion of the optical fiber, and the end of the fiber at the end face of the connection portion becomes depressed. In addition, the durability of the polishing layer also decreases. On the other hand, when the degree of saponification exceeds 97 mol%, the solubility of the binder becomes poor and scratches on the polished surface increase.

  In addition, as water-soluble binder resin soluble in water, it can replace with said polyvinyl alcohol and can use a cellulose resin. Cellulosic resins have many hydroxyl groups (—OH), which are hydrophilic groups, but are not soluble in water as they are. The reason is that water cannot enter between celluloses because the hydroxyl group has a strong hydrogen crystal structure between molecules.

Therefore, by replacing a part of the hydrogen atom of the hydroxyl group of cellulose with a methyl group (—CH ₃ ), a hydroxypropyl group (—CH ₂ CHOHCH ₃ ), a hydroxyethyl group (—CH ₂ CH ₂ OH), or the like, What became water-soluble by eliminating the hydrogen bond can be used as the binder resin 14 of the polishing layers 15a and 15b. As such cellulose, carboxymethyl cellulose (CMC) can be used (for example, CMC Daicel, 1350, manufactured by Daicel Chemical Industries).

  Furthermore, in addition to the water-soluble binder resin described above, glycols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol can be added to the polishing layers 15a and 15b as a lubricant. The glycol compound acts as a lubricant on the fine abrasive particles 12 and the spherical auxiliary particles 13 during polishing, thereby reducing the frictional resistance and acting to suppress the generation of scratches and work-affected layers.

  The polishing film 10a according to the first embodiment shown in FIG. 1A is manufactured by polishing particles dispersed in a water-soluble binder resin such as polyvinyl alcohol having a saponification degree of 85 to 97 mol% and an organic solvent (isopropyl alcohol). 12 and mixed well to prepare a coating solution. Further, a glycol compound is added to the coating solution to make the abrasive particles 12 have dispersibility and lubricity. Further, a surfactant may be added.

  As the abrasive particles 12, colloidal silica particles having an average particle diameter of 10 nm to 30 nm are used. The amount of the abrasive particles 12 is preferably in the range of 80 wt% to 98 wt% with respect to the polishing layer 15 a including the abrasive particles 12 and the binder resin 14.

  The viscosity of the coating solution is adjusted so that the polishing layer 10a is uniform. The viscosity of the coating solution is preferably in the range of 5 cps to 200 cps.

  Next, this coating solution is applied to the surface of the base film 11, the coating solution is dried and cured, and further processed into a predetermined shape, whereby the polishing film 10 a of the first embodiment illustrated in FIG. Is obtained.

  A blade coater, a die coater, a gravure coater, a knife coater, a reverse roll coater, a cast coater, a spray coater, a coater coater, or the like can be used to apply the coating solution in which the abrasive particles 12 are dispersed to the surface of the base film 11. .

  In the production of the abrasive film 10b of the second embodiment shown in FIG. 1B, in addition to the abrasive particles 12, spherical auxiliary particles 13 having an average particle diameter of 70 nm to 150 nm are added. The material of the spherical auxiliary particles can be acrylic, polyester, or urethane in addition to colloidal silica. The weight ratio between the abrasive particles 12 and the spherical auxiliary particles 13 is in the range of 90:10 to 70:30. Furthermore, the total amount of the abrasive particles 12 and the spherical auxiliary particles 13 is preferably in the range of 80% by weight to 98% by weight with respect to the polishing layer 15a.

The coating solution to which the spherical auxiliary particles 13 are added is manufactured in the same manner as the manufacturing method of the polishing film 10a of the first embodiment, applied to the base film 11, the coating solution is dried and cured, and further, a predetermined shape is formed. To obtain the polishing film 10b of the second embodiment shown in FIG. 1 (b).
<Polishing method>
Hereinafter, a polishing method using the polishing film according to the present invention will be described.

  FIG. 2 is a schematic cross-sectional view of an optical fiber connection portion of an optical fiber connector, which is an object to be polished, polished by the polishing method of the present invention described below. FIG. 2A is a schematic front view of FIG. 2A, and FIG.

  As shown in FIGS. 2A and 2B, the optical fiber connector 20 in the optical fiber connector includes an optical fiber 21 made of quartz glass and a ferrule 22 in which the periphery of the optical fiber 21 is coated with zirconia. 21 is located along the center of the ferrule 22 and is fixed to the ferrule 22 with an adhesive resin 23.

  As shown in FIG. 2A, the polished end face 24 of the optical fiber has a substantially curved shape such that the central portion where the optical fiber 21 is located is convex, and a step between the optical fiber 21 and the ferrule. Is polished so as to be within an allowable range (within ± 50 nm). In this way, by polishing the end face of the connection portion of the optical fiber, it is possible to suppress the occurrence of light scattering and the like and to further reduce the loss of light amount transmission at the joint portion between the optical fibers.

  The above-described polishing can be achieved by the polishing method according to the present invention described below.

  FIG. 3 shows a schematic sectional view of a polishing apparatus used in the polishing method according to the present invention. The polishing apparatus whose outline is shown in FIG. 3 has a known structure (see JP-A-6-179161).

  As shown in FIG. 3, the polishing apparatus 30 mainly includes a polishing disk 33, a rotating disk 32 that integrally supports the polishing disk 33, and a disk drive mechanism (not shown) that rotationally drives the rotating disk 32. A polishing apparatus base 35 having a zipper) inside.

  The polishing apparatus base 35 is provided with a polishing holder support member 36, and an optical fiber fixing plate 37 is positioned with respect to the polishing holder support member by positioning pins 38 on the upper surface thereof. The polishing holder support member 36 can move up and down, and can adjust the height position of the end face of the optical fiber connection portion, which is a polishing surface.

  The polishing film 34 (select one of the polishing films 10a and 10b of the present invention) is held on a polishing board 33 made of an elastic body (rubber plate) installed on the rotating disk 32. By the disk drive mechanism, the rotating disk 32 is set so as to perform a rotation motion about the center X as a center of rotation and a revolving motion around a position Y that is eccentric from the center of rotation by a required amount (E). Has been. The use of the polishing film 34 is not unevenly distributed in a part thereof.

  The optical fiber connector (20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h, 20i, 20j, 20k, 20l) of the optical fiber connector that is the object to be polished is a set of 12 pieces of the circular optical fiber fixing plate 37. It is attached to the optical fiber fixing plate 37 by the fixing nut 40 in the holes equally divided in the outer peripheral portion (in FIG. 3, only the optical fiber connecting portions 20a and 20b are shown. Hereinafter, the “optical fiber connecting portion 20” is generically shown. Called).

  In the polishing apparatus 30, a metal weight 39 is placed at the center of the optical fiber fixing plate 37 so that a load is uniformly applied to the entire twelve of the optical fiber connection portions 20, and is supported so as to be slidable in the vertical direction perpendicular to the polishing sheet. In addition, a support member (not shown) that presses the optical fiber connection portion 20 against the polishing film 34 at a predetermined pressure during polishing is provided.

  FIG. 4 shows a schematic diagram during polishing of the end face of the optical fiber connecting portion by the polishing method of the present invention (FIG. 4 shows the optical fiber connecting portion 20a). As shown in FIG. 4, the polishing film 10b (FIG. 1 (b)) of the present invention is disposed on a polishing board 33 made of an elastic body (rubber plate), and the optical fiber connection portion 20a is disposed on the surface of the polishing film 10b. In a state where the end face 24 of the connecting portion is pressed, the polishing board 33 (see FIG. 3) rotates and revolves around the rotation radius at a position eccentric from the rotation center by a required amount (E). The end face 24 is polished.

  In the present embodiment, a predetermined amount of water is sprayed on the polishing film 10b as a lubricating liquid before polishing. The first polishing is performed with this predetermined amount of water, and no additional spraying is performed. After the completion, in the next second polishing, the first polishing liquid is wiped off, and the same amount of water is sprayed as in the first polishing.

  In the polishing film 10 b, a part of the binder on the surface of the polishing layer 15 b is dissolved during polishing, and the dissolved particles 12 and spherical auxiliary particles 13 of the dissolved portion act as free abrasive grains 18. Polyvinyl alcohol, which is a water-soluble polymer material, is used as the binder resin 14, and the polyvinyl alcohol is not dissolved at a time, but by the connection portion end face 24 of the optical fiber connection portion 20 and the pressing pressure. It gradually dissolves from the surface of the contacted polishing layer 15b.

  Thus, the abrasive particles 12 and the spherical auxiliary particles 13 released during polishing can be uniformly supplied to the connection portion end face 24 of the optical fiber. Therefore, since the abrasive particles are present in the end face 24 of the optical fiber in a fluid manner compared to the conventional abrasive film that is polished only by the fixed abrasive particles, the generation of scratches is suppressed, and the smoothness is within the allowable step (within ± 50 nm). A finished polished surface is obtained. In addition, uniform polishing is possible for other optical fiber connection portions that are polished simultaneously.

  The polishing method using the polishing film 10b including the abrasive particles 12 and the spherical auxiliary particles 13 has been described. However, even when the polishing film 10a not including the spherical auxiliary particles 13 is used, the binder resin 14 is highly soluble in water. Since the molecular material polyvinyl alcohol is used, the abrasive particles 14 are fluidly present on the end face 24 of the optical fiber, and the occurrence of scratches is suppressed, and convex smooth finish polishing within an allowable step (within ± 50 nm). A surface is obtained.

In the polishing method using the polishing film according to the present invention, the surface to be polished and the polishing layer are polished by pressing and moving relative to each other via an aqueous solution containing water or a lubricant. A part of the binder resin is dissolved, and along with this, a part of the abrasive particles (or a part of each of the abrasive particles and the spherical auxiliary particles) acts as free abrasive particles. Therefore, in the polishing method of the present invention, polishing proceeds by the action of both abrasive particles fixed to the abrasive film and free abrasive particles (or abrasive particles and spherical auxiliary particles). As a result, the finish surface is made of a different material, such as the end face of an optical fiber connection made of a different material. it can.
<Example>
Below, the Example and comparative example of this invention are examined, and the evaluation result of the characteristic is shown.
<Examples 1 and 2 and Comparative Examples 1 and 2>
In Examples 1 and 2 and Comparative Examples 1 and 2, the relationship of the average particle diameter of the abrasive particles contained in the polishing layer is compared.
Example 1
In Example 1, polyvinyl alcohol powder (trade name: EG-25, manufactured by Nippon Synthetic Chemical Co., Ltd .: saponification degree: 86.5 to 89.0 mol%, estimated polymerization degree: 1700 to 1850) (solid content: 6% by weight) is a binder resin. Was dissolved in pure water to prepare a binder solution.

In this binder liquid, a liquid in which colloidal silica having an average particle diameter of 10 to 15 nm serving as abrasive particles is uniformly dispersed in isopropyl alcohol (trade name IPA-ST, manufactured by Nissan Chemical Co., Ltd .: 30 wt% dispersion) has a solid content. Was added to 94% by weight, and propylene stirring and ultrasonic vibration were added, followed by thorough stirring. Then, 9 g of an alkylene glycol solution (trade name MFDG, manufactured by Sato Special Oil Co., Ltd.) was added, and the mixture was further stirred to obtain a coating solution. Was made.
(Example 2)
Example 2 used an alcohol solution (trade name IPA-ST-MS, manufactured by Nissan Chemical Industries, Ltd .: 30 wt% dispersion) in which colloidal silica having an average particle size of 17 to 23 nm serving as abrasive particles was dispersed.

  The polyvinyl alcohol used in Example 1 and Example 2 is a polyvinyl resin obtained by polymerizing vinyl acetate and saponifying it, and having a saponification degree of 85 mol% to 97 mol%.

  Next, each of the prepared coating solutions of Examples 1 and 2 was uniformly applied to the surface of a 75 μm thick polyethylene terephthalate (PET) film by a reverse coater type coater (thickness, about 80 μm). And then heated at 110 ° C. for 1 minute in a dryer (evaporation of the solvent in the binder resin). Furthermore, a polishing layer (thickness 5 μm) was formed by heat treatment in an atmosphere of 100 ° C. for 60 minutes.

Next, this polishing sheet was processed into a predetermined disk, and the polishing sheets of Example 1 and Example 2 for testing were obtained. And the polishing sheet of Example 1 and Example 2 was used for the finish grinding | polishing of the optical fiber connection part end surface, respectively. Here, as the PET film, a film obtained by extruding PET and a polyester resin together and then stretched, that is, a primer-treated film was used.
(Comparative Examples 1 and 2)
In Comparative Example 1, the average particle size of colloidal silica as abrasive particles was 40 to 50 nm (trade name IPA-ST-L, manufactured by Nissan Chemical Co., Ltd .: 30 wt% dispersion). In Comparative Example 2, colloidal was used as abrasive particles. The average particle diameter of silica was set to 70 to 100 nm (trade name IPA-ST-ZL, manufactured by Nissan Chemical Co., Ltd .: 30 wt% dispersion).

  Comparative Examples 1 and 2 were the same as Example 1 except for the abrasive particles.

  The polishing films of Examples 1 and 2 and Comparative Examples 1 and 2 were each subjected to finish polishing of the connection end face of the optical fiber according to a normal polishing process, and tested for scratches, processing steps, deposits, and durability of the polishing film.

  The optical fiber connection used in the polishing test was a multi-stage polished and polished with # 8000 (average particle diameter 1 μm) diamond particles.

  As the polishing test apparatus, a polishing apparatus (SFP-120A) manufactured by Seiko Giken Co., Ltd. was used. The polishing files manufactured as Examples 1 and 2 and Comparative Examples 1 and 2 were each processed into a disk shape having a diameter of 127 mm, and attached to a rotating plate of a rubber pad (hardness: 80 duro) having a thickness of 5 mm.

  On the other hand, a jig in which 12 optical fiber connection portions having an outer diameter of 2.5 mm were set was prepared. And just before polishing, 1 cc of ion-exchanged water is dropped on the surface of the polishing film, and an optical fiber connection is performed while applying a load of 4.8 kg to the entire twelve optical fiber connection portions and rotating the rotating plate at 70 rpm. The part was subjected to planetary motion with rotation and revolution on the polishing file, and the end face of the connection part was polished for a certain time (60 seconds). After polishing, washing with water was performed to clean the connection portion end face, and then the polished connection portion end face was evaluated.

  Since scratches affect the reflection loss of light, it is desirable that scratches are not present in the fiber portion. In addition, since there is a possibility that the ferrule part has scratches also in the fiber part, the same evaluation was made. Optical fiber connectors with scratches are subject to re-polishing.

  If the processing step is within ± 50 nm, there is no problem, but a slightly plus value (convex) in the protruding state is preferable to a minus value (concave) in a state where the end of the optical fiber is recessed from the end surface of the connection portion. .

  There is no problem with the deposits that can be removed by ordinary pure water cleaning, but when it is necessary to wipe off with a non-woven fabric or the like, there is a problem because the cleaning process increases.

  The scratches (scratches) on the end face of the optical fiber connection after polishing were determined by observing the polished end face with a microscope having a magnification of 400 times and the number of fibers having scratches in the 12 polished optical fiber connections. When there were 0 scratches, it was evaluated as symbol ０, when it was 1-2, symbol ○, when it was 3-4, symbol Δ, and when it was 5 or more, it was evaluated as symbol x.

  A step difference between the end of the optical fiber and the end of the ferrule at the end face of the optical fiber connection was measured (measuring instrument: Direct Optical Research, ZX-1, ARRAY was used). In the evaluation, the difference in height between the center position of the virtual curve on the ferrule end face and the center position of the optical fiber end face is a step. When the level difference is a positive value, the end face of the optical fiber protrudes from the end face of the ferrule, the negative value is a depression, and the optimal value is when the level difference is near ± 0 nm, and the allowable value is ± 50 nm.

  The durability was indicated by the number of times of polishing (life of the polishing film) that can be satisfactorily polished with one polishing film placed in the polishing apparatus.

  Table 1 shows the evaluation results 1 of Example 1 and Example 2, and Comparative Example 1 and Comparative Example 2.

  As shown in Table 1, in Examples 1 and 2, a polishing layer formed of polyvinyl alcohol soluble in water as a binder resin and colloidal silica particles having an average particle diameter of 10 to 15 nm and 17 to 23 nm. As a result of the final polishing, the polishing within the allowable step range was achieved without causing scratches on the end face of the optical fiber connection portion by shavings. However, the durability is still not enough.

On the other hand, Comparative Example 1 and Comparative Example 2 use water-soluble polyvinyl alcohol as the binder resin as in Example 1 and Example 2, but the average particle diameter of the abrasive particles is 40 to 50 nm and Since it is as large as 70 to 100 nm, scratches are generated on the fiber end face, and the step of the dent is large.
(Examples 3 to 8 and Comparative Examples 3 to 6)
Next, an example and a comparative example regarding the relationship between the combination of abrasive particles and auxiliary particles and the weight ratio thereof will be compared below.

  As the abrasive particles, colloidal silica having a particle size of 10 to 15 nm, 17 to 23 nm, and 40 to 50 nm is used. As spherical auxiliary particles, colloidal silica particles having a particle size of 40 to 50 nm and 70 to 100 nm and spherical particles having an average particle size of 100 nm are used. Acrylic particles (product name, Technopolymer XX-02GQ, manufactured by Sekisui Plastics Co., Ltd.) were used, and isopropyl alcohol dispersions in which abrasive particles and spherical auxiliary particles were mixed were used. Other additives and production methods were the same as in Example 1. Table 2 shows the blending conditions of the abrasive particles and the spherical auxiliary particles.

(Example 3)
In Example 3, colloidal silica particles having a particle diameter of 10 to 15 nm were used as abrasive particles, colloidal silica particles having a particle diameter of 70 to 100 nm were used as auxiliary particles, and the weight ratio was mixed to 80:20. The content of abrasive particles and auxiliary particles in the polishing layer was adjusted to 94% by weight and the binder resin to 6% by weight. Others were the same as in Example 1.
Example 4
In Example 4, the weight ratio of the abrasive particles to the auxiliary particles in Example 3 was changed to 90:10, and the others were the same as in Example 3.
(Example 5)
In Example 5, the weight ratio of the abrasive particles to the auxiliary particles in Example 3 was changed to 70:30, and the others were the same as in Example 3.
(Example 6)
In Example 6, the abrasive particles of Example 3 were replaced with colloidal silica particles having a particle diameter of 17 to 23 nm, and the others were the same as Example 3.
(Example 7)
In Example 7, the auxiliary particles in Example 3 were replaced with spherical acrylic particles having an average particle diameter of 100 nm, and the others were the same as in Example 3.
(Comparative Example 3)
In Comparative Example 3, the weight ratio between the abrasive particles and the auxiliary particles in Example 3 was changed to 60:40, and the others were the same as in Example 3.
(Comparative Example 4)
In Comparative Example 4, the auxiliary particles in Example 3 were replaced with colloidal silica particles having an average particle diameter of 40 to 50 nm, and the others were the same as in Example 3.
(Comparative Example 5)
In Comparative Example 5, the abrasive particles of Example 3 were replaced with colloidal silica particles having an average particle diameter of 40 to 50 nm, and the others were the same as Example 3.

  Using the polishing films of Examples 3 to 7 and Comparative Examples 3 to 5, the same polishing test as in Evaluation 1 was performed, and the evaluation results 2 of evaluating the polishing characteristics are shown in Table 3.

  As shown in Table 2, in Examples 3 to 7, colloidal silica abrasive particles having an average particle size of 10 to 15 nm and 17 to 23 nm, and spherical auxiliary particles having an average particle size in the range of 70 to 100, Each was mixed in a range of 70:30 to 90:10 as a content ratio, and polished using a polishing film fixed with a binder resin of polyvinyl alcohol. As shown in Evaluation result 2 in Table 3, in Examples 3 to 7, finish polishing with few scratches and processing steps was achieved. Furthermore, it was able to be polished as a polishing film having excellent durability 5 times or more.

  In particular, in Example 7, the spherical auxiliary particles were not colloidal silica particles but spherical acrylic particles having an average particle diameter of 100 nm, but good polishing was possible. Further, in Example 4, deposits were detected, but they could be easily removed by washing and were not particularly problematic.

  On the other hand, in Comparative Examples 3 to 5, the content ratio of the abrasive particles to the auxiliary particles is 60:40 (Comparative Example 3), the average particle diameter of the auxiliary particles is 40 to 50 nm (Comparative Example 4), and the spherical auxiliary The average particle size of the particles is set to 40 to 50 nm (Comparative Example 5) and is not set in the range of Examples 3 to 7, respectively, but any value of scratch, processing step and deposit is rejected. It has become.

  Next, the polishing characteristics obtained by polishing the end face of the optical fiber connection portion using each of the polishing films produced by changing the saponification degree of polyvinyl alcohol used as the binder resin will be described.

In Examples 8 and 9, and Comparative Examples 6 and 7, those having different saponification degrees of polyvinyl alcohol as binder resins were used as follows. Otherwise, the production of the abrasive film was the same as in Example 3.
(Example 8)
In Example 8, polyvinyl alcohol (GH-17, Nippon Synthetic Chemical Industry) having a saponification degree of 86.5 to 89.0 mol% was used as a binder resin.
Example 9
In Example 9, polyvinyl alcohol (AH-17, Nippon Synthetic Chemical Industry) having a saponification degree of 97.0 to 98.5 mol% was used as the binder resin.
(Comparative Example 6)
In Comparative Example 6, polyvinyl alcohol (N-300, Nippon Synthetic Chemical Industry) having a saponification degree of 98.0 to 99.0 mol% was used as the binder resin.
(Comparative Example 7)
In Comparative Example 7, polyvinyl alcohol (KH-17, Nippon Synthetic Chemical Industry) having a saponification degree of 78.5 to 81.5 mol% was used as the binder resin.

  Using the polishing films of Examples 8 and 9 and Comparative Examples 6 and 7, the same polishing test as in Evaluation 1 was performed. It shows in Table 4 as the evaluation result 3 which evaluated the grinding | polishing characteristic.

  As shown in Table 4, in Examples 8 and 9, by using polyvinyl alcohol with a saponification degree of 86.5 to 89.0 mol% and 97.0 to 98.5 mol%, scratches, processing steps, Good results were obtained for both deposits and durability was 15 times or more. In Example 9, since the processing step was −40 nm and was close to the limit of the allowable range (within ± 50 nm), the saponification degree of polyvinyl alcohol used as the binder resin was 85 to 85 in consideration of the above result. 97 mol% is a preferable numerical range.

  On the other hand, in Comparative Example 6, the degree of saponification is as large as 98.0 to 99.0 mol%, and the polyvinyl alcohol is hardly dissolved in water. The fiber part was excessively polished, forming a recess that became a recess exceeding the allowable range of processing steps (within ± 50 nm), and scratches were also generated.

  In Comparative Example 7, since the degree of saponification is as low as 78.5 to 81.5 mol%, the polyvinyl alcohol itself is soft and sticky, and an adhering matter is formed on the entire end face of the optical fiber connection portion, and the adhering matter is fixed. High-precision polishing was not possible. Moreover, since the polishing layer was soft, the entire polishing layer was worn out by one polishing.

  As described above, according to the present invention, even in finish polishing in which the surface to be polished is made of two different materials, such as the end face of the optical fiber connector in the optical fiber connector, the step is kept within an allowable range and smooth without scratches. Polishing is possible.

  The polishing film according to the present invention and the polishing method using the same are not limited to the polishing of the end face of the connection portion of the optical fiber connector, but the air bearing surface polishing of the thin film head for magnetic hard disk, the polishing of the semiconductor device element surface and the lens, crystal This is effective for finish polishing of materials and the like.

DESCRIPTION OF SYMBOLS 10a, 10b Polishing film 11 Base film 12 Polishing particle 13 Spherical auxiliary particle 14 Binder resin 15a, 15b Polishing layer 20, 20a, 20b Optical fiber connection part 21 Optical fiber 22 Ferrule 24 Optical fiber connection part end surface

Claims (10)

A substrate film that is a substrate of the polishing film, and a polishing layer formed on the substrate film,
The polishing film comprises abrasive particles and a binder resin that fixes the abrasive particles, and the binder resin is a water-soluble binder resin.   The abrasive film according to claim 1, wherein the binder resin comprises partially saponified polyvinyl alcohol having a saponification degree in the range of 85 mol% to 97 mol%.   The polishing film according to claim 1, wherein the polishing layer further comprises a glycol-based compound.   The abrasive film according to any one of claims 1 to 3, wherein the abrasive particles are colloidal silica particles having an average particle diameter in the range of 10 nm to 30 nm.   The polishing film according to claim 4, wherein the colloidal silica particles are 80 wt% to 98 wt% with respect to the polishing layer.   The abrasive particles are colloidal silica particles having an average particle diameter of 10 nm to 30 nm, and the polishing layer further includes spherical auxiliary particles having an average particle diameter of 70 nm to 150 nm, and the colloidal silica The abrasive film according to any one of claims 1 to 3, wherein the weight ratio of the particles to the spherical auxiliary particles is in the range of 90:10 to 70:30.   The polishing film according to claim 6, wherein the total amount of the colloidal silica particles and the spherical auxiliary particles is in the range of 80 wt% to 98 wt% with respect to the polishing layer. A polishing method using the polishing film according to any one of claims 1 to 7,
A first step of pressing the surface of the object to be polished against the polishing layer of the polishing film fixed on the polishing disk of the polishing apparatus;
A second step of polishing the polishing disk to which the polishing film is fixed and the surface of the object to be polished pressed by the polishing layer by relatively moving while maintaining the pressed state; Comprising
In the second step, a polishing method is characterized in that a predetermined amount of water or an aqueous solution containing a lubricant is dropped in advance on the surface of the polishing layer.   9. The polishing method according to claim 8, wherein in the second step, the polishing disk performs a rotational motion including a rotational motion and a revolving motion. The polishing method according to claim 8 or 9, wherein the surface of the object to be polished is an end face of an optical fiber connecting portion in an optical fiber connector.

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