JP2019108472A - Abrasive holding material for abrasive pads, resin composition, and production method of abrasive holding material for abrasive pads - Google Patents

Abstract

To provide an abrasive holding material for abrasive pads having pores having precisely controlled size distribution on a surface of unsaturated polyester.SOLUTION: An abrasive holding material for abrasive pads characterized by cured product of a resin composition including (A) an unsaturated polyester resin, (B) an ethylenically unsaturated compound, (C) an inorganic filler, and (D) a hollow body.SELECTED DRAWING: None

Description

  The present invention relates to a polishing agent holding material for a polishing pad, a resin composition, and a method for producing a polishing agent holding material for a polishing pad.

  A polishing sheet, which is one type of polishing agent holding material for polishing pads, uses a non-woven fabric or a woven fabric made of synthetic fibers and synthetic rubbers, or a polyester film as a base material, and a polyurethane solution is coated on the upper surface thereof A porous layer having continuous pores is formed by a wet coagulation method, and if necessary, the skin layer is ground and removed (hereinafter referred to as a polishing sheet whose surface is ground is referred to as suede). Such a polishing sheet is already widely used in polishing pads used from rough polishing to finish polishing for surface precision polishing of electronic parts such as liquid crystal glass, glass disk, photomask silicon wafer, CCD, and cover glass. There is. In recent years, coupled with the development of measurement equipment for precision polishing surfaces, quality requirements from users have become high, and polishing pads capable of precision polishing with higher precision have been required.

  Conventionally, a chemical mechanical polishing (CMP) method has been adopted for flattening processing of precision parts such as magnetic disk substrates, optical lenses, and semiconductor wafers. In the CMP method, usually, a slurry (polishing liquid) in which abrasive grains (abrasive particles) are dispersed in an alkali solution or an acid solution is supplied between the processing surface of the object to be polished and the polishing pad. During polishing, the workpiece is planarized by the mechanical polishing action by the abrasive grains in the slurry and the chemical polishing action by the alkaline solution or the acid solution.

  In such a CMP method, as a polishing pad used particularly for finish polishing, one using a porous flexible polyurethane foam excellent in abrasion resistance for a polishing layer is known. However, in this type of polishing pad, the polishing layer has high flexibility and is easily deformed by compression, so the polishing layer follows the shape of the end portion of the object to be polished during polishing, and the end portion of the object to be polished is An over-polishing phenomenon occurs, which is "end sag" which is largely polished. In addition, the fine holes present on the surface of the polishing layer are partially blocked by friction in the process of polishing, generating polishing flaws on the surface to be polished, and the polishing rate is lowered with time.

  Increasing the hardness of the polishing layer of the polishing pad has been studied as a technique for preventing edge sag. For example, in patent document 1, making a nonwoven fabric into a high modulus is examined by forming an entangled point by mixing a heat-fusion yarn with polyester fiber. In patent document 2, it is examined by suppressing the hardness of a grinding layer in a fixed range, and suppressing generation | occurrence | production of a grinding | polishing damage, and preventing end part dripping by making the structure of the bubble in foaming polyurethane into a specific thing. There is.

Unexamined-Japanese-Patent No. 2006-35322 JP 2012-714 A

It has been found that the size and distribution of pores in the polishing sheet greatly affect the polishing accuracy, and the development of techniques for controlling these is important.
However, Patent Document 1 does not focus on the control of pore size and distribution, and the polishing system is low.

  Moreover, control of the cell structure by foaming of the polyurethane resin in patent document 2 is limited, It could not be said that it is a practical technique.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an abrasive holding material for a polishing pad having pores of a precisely controlled size distribution on the surface of unsaturated polyester.

  The inventors of the present invention have conducted intensive studies to solve the above problems, and use the resin composition containing an unsaturated polyester resin, an ethylenically unsaturated compound, an inorganic filler, and a hollow body to perform polishing. The inventors have found that it is possible to precisely control the opening diameter of the surface of the pad abrasive holding material, and the present invention is conceived.

  That is, the present invention has the following aspects.

[1] A cured product of a resin composition comprising (A) unsaturated polyester resin, (B) an ethylenically unsaturated compound, (C) an inorganic filler, and (D) a hollow body. Abrasive holding material for polishing pads.
[2] The polishing agent holding material for a polishing pad according to [1], wherein the resin composition does not contain inorganic fibers.
[3] The resin composition comprises the (D) hollow body with respect to a total of 100 parts by mass of the (A) unsaturated polyester resin, (B) an ethylenically unsaturated compound, and (C) an inorganic filler. The abrasive holding material for a polishing pad according to [1] or [2], which contains 10 to 50 parts by mass.
[4] The resin composition comprises 80 to 100 parts by mass of the (B) ethylenically unsaturated compound with respect to 100 parts by mass of the (A) unsaturated polyester resin. The abrasives holding material for polishing pads in any one of 3].
[5] The abrasive holding material for a polishing pad according to any one of [1] to [4], wherein the weight average molecular weight of the (A) unsaturated polyester resin is 6,000 to 35,000. .
[6] The hollow body (D) is at least one selected from a glass balloon, a silica balloon, an alumina balloon, a ceramic balloon, and a shirasu balloon, according to any one of [1] to [5]. The abrasives holding material for polishing pads as described above.
[7] The abrasive holding material for a polishing pad according to [6], wherein the hollow body (D) is a glass balloon.
[8] The inorganic filler (C) is at least one selected from aluminum hydroxide, barium sulfate, talc, kaolin, calcium sulfate, calcium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, calcium hydroxide and calcium oxide An abrasives holding material for a polishing pad according to any one of [1] to [7], which is characterized in that
[9] (A) unsaturated polyester resin, (B) ethylenically unsaturated compound, (C) inorganic filler, and (D) hollow body, containing no inorganic fiber, and (A) non-containing The resin composition which contains 10-50 mass parts of said (D) hollow bodies with respect to a total of 100 mass parts of saturated polyester resin, (B) ethylenic unsaturated compound, and (C) inorganic filler.
[10] Forming and curing a resin composition containing (A) unsaturated polyester resin, (B) ethylenic unsaturated compound, (C) inorganic filler, and (D) hollow body, A method for producing an abrasives holding material for a polishing pad, comprising scraping the surface of a cured resin composition to make the surface exposed.

  According to the present invention, it is possible to provide an abrasive holding material for a polishing pad having pores of precisely controlled size distribution on the surface of unsaturated polyester.

  Hereinafter, the manufacturing method of the abrasives holding material for polishing pads of the present invention, the resin composition, and the abrasives holding material for polishing pads is explained in detail. The present invention is not limited to only the embodiments shown below.

(Resin composition)
One embodiment of the present invention is a resin composition comprising (A) unsaturated polyester resin, (B) ethylenically unsaturated compound, (C) inorganic filler, and (D) hollow body.

[(A) unsaturated polyester resin]
The unsaturated polyester resin (A) is obtained by polycondensation of a polyhydric alcohol with an unsaturated polybasic acid and an optional saturated polybasic acid, and the type thereof is not particularly limited. An unsaturated polybasic acid is a polybasic acid having an ethylenically unsaturated group, and a saturated polybasic acid is a polybasic acid having no ethylenically unsaturated group. The unsaturated polyester resin (A) may be only one kind or two or more kinds. The unsaturated polyester resin (A) can be synthesized by a known synthesis method.

  (A) Examples of polyhydric alcohols used as raw materials for unsaturated polyester resins include ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neopentanediol, hydrogen And bisphenol A, bisphenol A, glycerin and the like. Among them, preferred are propylene glycol and hydrogenated bisphenol A. The polyhydric alcohols may be used alone or in combination of two or more.

  As an unsaturated polybasic acid used as a raw material of (A) unsaturated polyester resin, maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid etc. are mentioned, for example. The unsaturated polybasic acids may be used alone or in combination of two or more. Among these, maleic anhydride and fumaric acid are preferable.

  As a saturated polybasic acid, for example, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, hetic acid, succinic acid, adipic acid, sebacic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, endo methylene tetrahydrophthalic anhydride An acid etc. are mentioned. Among them, phthalic acid is preferred. The saturated polybasic acids may be used alone or in combination of two or more.

  The weight average molecular weight of the unsaturated polyester resin (A) is preferably 6,000 to 35,000, more preferably 6,000 to 20,000, and still more preferably 8,000 to 15,000. When the weight average molecular weight is 6,000 to 35,000, the moldability is further improved. The weight average molecular weight is a value measured using gel permeation chromatography (GPC). The measurement method is shown in the examples.

The degree of unsaturation of the unsaturated polyester resin (A) is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, and still more preferably 70 to 100 mol%. When the degree of unsaturation is in the above range, the formability is better. The degree of unsaturation of the unsaturated polyester resin can be calculated by the following equation using the number of moles of the unsaturated polybasic acid and the saturated polybasic acid used as the raw materials.
Degree of unsaturation (mol%) = {(mol of unsaturated polybasic acid) / (mol of unsaturated polybasic acid + mol of saturated polybasic acid)} × 100

  The blending amount of the unsaturated polyester resin (A) is preferably 10.0 to 20.0% by mass, more preferably 10.0 to 18.0% by mass, and still more preferably 10. It is 0 to 17.0 mass%. (A) If the compounding quantity of unsaturated polyester resin is 10.0 mass% or more, mechanical strength will be more favorable, and if it is 20.0 mass% or less, it will become a viscosity suitable for handling.

[(B) Ethylenically unsaturated compound]
(B) Ethylenically unsaturated compound is a compound having an ethylenically unsaturated group. As the ethylenically unsaturated compound (B), any compound having a double bond copolymerizable with the (A) unsaturated polyester resin can be used without particular limitation.

  (B) Ethylenically unsaturated compounds include, for example, aromatic monomers such as styrene, vinyl toluene, vinyl benzene, 2-hydroxyethyl methacrylate, diacrylate derivative of polyalkylene oxide, triethylene glycol di (meth) acrylate, Acrylic monomers such as tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and methyl methacrylate, and oligomers in which a plurality of the above monomers are bonded, and the like. Among them, styrene and methyl methacrylate are preferable from the viewpoint of the reactivity with the (A) unsaturated polyester resin, and styrene is particularly preferable. The ethylenically unsaturated compounds (B) may be used alone or in combination of two or more.

  The content of the ethylenically unsaturated compound (B) is preferably 80 to 100 parts by mass, more preferably 83 to 98 parts by mass, and still more preferably 100 parts by mass of the unsaturated polyester resin (A). Is 85 to 95 parts by mass. When the content of (B) the ethylenically unsaturated compound is 80 parts by mass or more with respect to 100 parts by mass of (A) unsaturated polyester resin, the viscosity is suitable for handling. In addition, when the content of (B) the ethylenically unsaturated compound is 100 parts by mass or less with respect to 100 parts by mass of (A) unsaturated polyester resin, the cured product of the resin composition having much better mechanical strength Is obtained.

  The deflection temperature under load of the cured product of the mixture of (A) unsaturated polyester resin and (B) ethylenic unsaturated compound is preferably 100 ° C to 140 ° C. When the deflection temperature under load is 100 ° C. or more, the temperature is not easily affected by wear due to frictional heat at the time of polishing, and generation of polishing scratches can be further suppressed. The deflection temperature under load of the cured product of the mixture of unsaturated polyester resin and (B) ethylenically unsaturated compound may exceed 140 ° C. Deflection temperature under load is measured in accordance with JIS K6911. 5.35.

[(C) inorganic filler]
(C) The inorganic filler has, for example, a function of adjusting the viscosity of the resin composition to a viscosity suitable for handling and a function of improving the moldability of the resin composition.

  (C) As the inorganic filler, inorganic fillers known in the art can be used. For example, aluminum hydroxide, barium sulfate, talc, kaolin, calcium sulfate, calcium carbonate, magnesium oxide, magnesium hydroxide, Calcium hydroxide, calcium oxide and the like can be mentioned. Among these, calcium carbonate, aluminum hydroxide and talc, which have a cost merit, are preferable, and calcium carbonate or aluminum hydroxide is more preferable. The (C) inorganic filler may be used alone or in combination of two or more. In addition, when the below-mentioned (D) hollow body is an inorganic substance, it is not classified into (D) hollow bodies but not (C) inorganic filler.

  The average particle diameter of the inorganic filler (C) is preferably 1 to 100 μm, more preferably 1 to 60 μm, from the viewpoint of the viscosity of the resin composition when forming a cured product of the resin composition. And 1 to 50 μm. (C) If the average particle diameter of the inorganic filler is 1 μm or more, the aggregation of the inorganic filler can be further suppressed, and if the average particle diameter of the inorganic filler is 100 μm or less, the moldability is better.

  (C) The average particle size of the inorganic filler can be determined by measuring the particle size of the inorganic filler at N = 100 using an electron microscope or an optical microscope and calculating the average.

  The shape of the inorganic filler (C) may be spherical or flat, and preferably spherical. (C) When the inorganic filler is spherical particles, the specific surface area is small, so the viscosity of the resin composition at the time of forming a cured product of the resin composition can be effectively reduced, and unfilled portions are produced. Can be effectively prevented.

  The content of the inorganic filler (C) is 250 to 450 parts by mass, more preferably 270 to 400 parts by mass, and still more preferably 300 to 350 parts by mass with respect to 100 parts by mass of the unsaturated polyester resin (A). It is a department. When the content of the inorganic filler (C) is 250 parts by mass or more with respect to 100 parts by mass of the unsaturated polyester resin (A), the viscosity is suitable for handling, and the formability becomes better. On the other hand, when the content of the (C) inorganic filler is 450 parts by mass or less with respect to 100 parts by mass of the (A) unsaturated polyester resin, the mechanical strength of the cured product becomes better.

[(D) hollow body]
Pores derived from the hollow body (D) present on the surface of the polishing layer play a role of holding an abrasive that is an abrasive (abrasive particles). By appropriately selecting the hollow body (D), the size distribution and the number per unit area of the pores derived from the hollow body (D) present on the surface of the polishing layer can be precisely and easily controlled. An abrasive holding material for a polishing pad having a desired size distribution and a number of pores per unit area according to the object to be polished can provide better precision polishing. For example, by using (D) hollow bodies having a small size distribution, it is possible to obtain an abrasive holding material having more uniform pores on the surface of the polishing layer. Such a polishing agent-retaining material can provide a more precise polishing surface because the load on the surface of the workpiece can be made uniform.

  The material of the hollow body (D) is not particularly limited, and those known in the art can be used. For example, a glass balloon, a silica balloon, an alumina balloon, a ceramic balloon, a shirasu balloon etc. are mentioned, Among these, a glass balloon is preferable.

  It is preferable to control the size of the hollow body (D) from the viewpoint of enhancing the adhesion with the resin component ((A) unsaturated polyester resin). Since the hollow body is generally a spherical surface having a smooth surface, when the particle diameter is too large, the contact area between the resin component and the hollow body decreases and the adhesion between the resin component and the hollow body decreases. There is. The decrease in adhesion may result in a decrease in properties such as mechanical strength of a molded article obtained from the resin composition. Therefore, the content ratio of the hollow body (D) having a particle diameter of 110 to 130 μm is preferably 80% by volume or more, more preferably 84% by volume or more, further preferably to the whole hollow body (D). Is 90% by volume or more. Further, by controlling the content ratio of the hollow body (D) as described above, it is possible to cause macropores that may cause problems such as causing variations in the load on the surface of the polishing object by the abrasives holding material. It may be substantially free and have uniform pores with an average pore diameter of 110 to 130 μm on the surface of the polishing layer. It does not specifically limit as a method of controlling the ratio of (D) hollow bodies which have a particle diameter of 110-130 micrometers, For example, what is necessary is just to blend a commercially available hollow body so that the said ratio may be obtained. The “proportion of (D) hollow body having particle diameter of 110 to 130 μm” in the present specification can be calculated from the volume-based particle size distribution determined by the laser diffraction / scattering method. If the proportion of the (D) hollow body having a particle diameter of 110 to 130 μm is 80% by volume or more, better precision abradability can be obtained. In addition, there is no restriction | limiting in particular in the upper limit of the ratio of (D) hollow body which has a particle diameter of 110-130 micrometers, All of (D) hollow bodies may have a particle diameter of 110-130 micrometers.

  From the viewpoint of giving more uniform pores, the standard deviation of the particle diameter of the (D) hollow body is preferably 3.0 to 10.0 μm, more preferably 3.0 to 8.0 μm, and 3.0 to 6.0 μm. More preferable.

  The pressure resistance of the hollow body (D) is not particularly limited, but is preferably 18 MPa or more. If the pressure resistance is 18 MPa or more, the mechanical strength of the (D) hollow body is more excellent, so that breakage of the (D) hollow body at the time of production and molding of the unsaturated polyester resin composition can be reduced. Furthermore, in resin foams such as polyurethane foams, the pores existing on the surface of the polishing layer are clogged by friction during polishing, and the polishing rate decreases with time, while the pressure resistance is 18 MPa or more (D In the case of an abrasives holding material including a hollow body, clogging of pores present on the surface of the polishing layer during polishing can be further suppressed, and the decrease in polishing rate with time can be further reduced. In addition, since the abrasive holding material containing a hollow body having a pressure resistance of 18 MPa or more (D) is excellent in compressive strength as compared with a resin foam such as polyurethane foam, deformation due to a force applied at the time of polishing is small. It is possible to suppress the dripping. In the present specification, “pressure resistance of (D) hollow body” means that 90% by volume of (D) hollow body is broken when pressure is applied to (D) hollow body according to ASTM D-3102. It means the pressure which remains without.

  The compounding amount of the hollow body (D) is preferably 10 to 50 parts by mass with respect to a total of 100 parts by mass of (A) unsaturated polyester resin, (B) ethylenic unsaturated compound, and (C) inorganic filler It is more preferable that it is 20-40 mass parts. (D) If the blending amount of the hollow body is 10 parts by mass or more, a sufficient amount of the polishing agent can be held at the time of polishing, so that a good polishing rate can be given. On the other hand, when the compounding amount of the (D) hollow body is 50 parts by mass or less, the mechanical strength of the abrasives holding material is good.

[Additive]
In addition to the components (A), (B), (C) and (D), the resin composition contains a curing agent, a low-shrinkage agent, a mold release agent, a thickener, a coloring agent, a polymerization inhibitor, etc. The following additives may be contained as required. These additives can be contained in the range which does not bar an effect of the present invention according to each object.

  As a curing agent, for example, t-butyl peroxy octoate, benzoyl peroxide, 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl Peroxides such as peroxybenzoate, dicumyl peroxide, di-t-butyl peroxide and the like can be mentioned. These curing agents may be used alone or in combination of two or more. The curing agent is preferably added in the range of 0.5 to 2.0 parts by mass with respect to a total of 100 parts by mass of (A) unsaturated polyester resin and (B) ethylenic unsaturated compound. 6 mass parts-1.5 mass parts are more preferred.

  As the low shrinkage agent, known thermoplastic resins can be used, and examples thereof include polystyrene, polyethylene, polymethyl methacrylate, polyvinyl acetate, saturated polyester, polycaprolactone and the like. The low-shrinkage agents may be used alone or in combination of two or more. The low-shrinkage agent is preferably added in the range of 10 to 20 parts by mass with respect to 100 parts by mass in total of (A) unsaturated polyester resin and (B) ethylenic unsaturated compound.

  Examples of the mold release agent include stearic acid, oleic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, stearic acid amide, oleic acid amide, silicone oil, synthetic wax and the like. The release agent may be used alone or in combination of two or more. The release agent is preferably added in the range of 3.0 to 8.0 parts by mass with respect to a total of 100 parts by mass of (A) unsaturated polyester resin and (B) ethylenic unsaturated compound, 0.5 to 7.0 parts by mass is more preferable.

  As a thickener, it is a compound which shows the thickening effect other than the (C) inorganic filler, and an isocyanate compound is illustrated. The thickeners may be used alone or in combination of two or more.

  A coloring agent is used when it is necessary to color a molded article, etc., and various inorganic pigments and organic pigments can be used. The amount of the coloring agent can be appropriately adjusted according to the degree of coloring of the desired molded article.

  As polymerization inhibitors, conventionally known ones such as hydroquinone, trimethylhydroquinone, p-benzoquinone, naphthoquinone, t-butylhydroquinone, catechol, p-tert-butylcatechol, 2,6-di-tert-butyl-4-methylphenol Can be used.

[Inorganic fiber]
The resin composition preferably does not contain inorganic fibers. As an inorganic fiber, glass fiber, carbon fiber, a metal fiber etc. are mentioned, for example. When inorganic fibers are contained in the resin composition, when the cured product of the resin composition is used as an abrasive holding material for a polishing pad, there is a possibility that the polishing object may be damaged by polishing.

  In the present specification and claims, “does not contain inorganic fibers” means that the content of inorganic fibers in the resin composition or its cured product is 0.1% by mass or less, and impurities It does not exclude what is mixed with other components such as.

(Method for producing resin composition)
The resin composition can be produced, for example, by a method of kneading each of the components (A), (B), (C) and (D) and an additive contained as required. There is no restriction | limiting in particular as a kneading | mixing method, For example, a double arm type kneader, a pressure type kneader, a planetary mixer etc. can be used. The kneading temperature is preferably 20 ° C to 50 ° C, more preferably 30 to 50 ° C. If the kneading temperature is 20 ° C. or more, the kneadability is further improved. If the kneading temperature is 50 ° C. or less, the polymerization reaction of the resin composition can be further suppressed. The kneading time can be appropriately selected according to each component and the ratio thereof.

  There is no restriction | limiting in particular about the order which knead | mixes each component at the time of manufacturing a resin composition. For example, it is preferable to mix a part or all of the (A) unsaturated polyester resin and (B) the ethylenically unsaturated compound and then mix other components, since a uniformly mixed resin composition is easily obtained.

(Manufacturing method of abrasives holding material for polishing pad)
The polishing agent holding material for a polishing pad is a cured product of a resin composition. The polishing agent holding material for polishing pads can be formed by shaping and curing the resin composition, and scraping the surface to make it come out. By shaving the surface of the cured product of the resin composition containing (D) hollow bodies, pores derived from (D) hollow bodies are formed on the surface.

  The method for molding and curing the resin composition is not particularly limited, but it is preferable to use a method of charging the resin composition in a mold and performing press molding. Although there is no restriction | limiting in particular as conditions in the case of press-forming, For example, they are conditions of temperature 130-160 degreeC, pressure 4-20 Mpa, and pressurization time 1-8 minutes.

  As a method of surfacing, a method using a plane polisher can be mentioned.

  Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited to the following examples.

<Method of measuring weight average molecular weight of unsaturated polyester resin>
The weight average molecular weight of the unsaturated polyester resin is measured using gel permeation chromatography (Shodex (registered trademark) GPC-101 manufactured by Showa Denko KK) under the following conditions, and determined using a standard polystyrene calibration curve.
Column: Showa Denko LF-804
Column temperature: 40 ° C
Sample: 0.2 wt% tetrahydrofuran solution of unsaturated polyester resin Flow rate: 1 mL / min Eluent: tetrahydrofuran Detector: RI-71S

<Preparation of Unsaturated Polyester Resin A1>
In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 100 mol of fumaric acid (manufactured by Kawasaki Kasei Kogyo Co., Ltd.) and 100 mol of propylene glycol (manufactured by Asahi Glass Co., Ltd.) were charged. Then, the temperature was raised to 200 ° C. while heating and stirring under a nitrogen gas flow to carry out an esterification reaction to obtain unsaturated polyester resin A1.

  The resulting unsaturated polyester resin A1 had a degree of unsaturation of 100 mol% and a weight average molecular weight of 12,000.

<Preparation of Unsaturated Polyester Resin A2>
In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 100 moles of fumaric acid (made by Kawasaki Kasei Kogyo Co., Ltd.) and 80 moles of propylene glycol (made by Asahi Glass Co., Ltd.), hydrogenated bisphenol A20 moles (manufactured by Maruzen Petrochemical Co., Ltd.) were charged. Then, the temperature was raised to 210 ° C. while performing heating and stirring under a nitrogen gas flow to carry out an esterification reaction to obtain unsaturated polyester resin A2.

  The obtained unsaturated polyester resin A2 had a degree of unsaturation of 100 mol% and a weight average molecular weight of 10,000.

<Examples 1 to 6>
0.015 parts by mass of hydroquinone, which is a polymerization inhibitor, is added to the above-mentioned unsaturated polyester resins A1 and A2, respectively, and the resultant is dissolved in styrene (B), which is an ethylenically unsaturated compound, to obtain unsaturated polyester resins A1 and A2. A mixture containing the above A1 or A2 and styrene, each having a solid content of 60% by mass, was prepared.

  Thereafter, a mixture containing the above A1 or A2 and styrene and the components (C), (D) and additives shown in Table 1 so that the composition (ratio) shown in Table 1 is obtained using a double-arm kneader The mixture was kneaded under a temperature condition of 30.degree. C. to obtain resin compositions of Examples 1 to 6.

As the (B) ethylenic unsaturated compound, (C) inorganic filler, (D) hollow body, low shrinkage agent, curing agent, and release agent shown in Table 1, the following were used.
(B) Ethylenically unsaturated compound: Styrene (manufactured by Asahi Kasei Chemicals)
(C) Inorganic filler: Aluminum hydroxide (manufactured by Showa Denko, average particle diameter 7 μm)
(D) Hollow body: Aluminosilicate balloon (Extendospheres (trademark) SG, made by Potters Barrotini, average particle diameter 120 μm, standard deviation of particle diameter 4.3 μm, pressure resistance 18.6 MPa)
Low-shrink agent: Polystyrene (Styron (trademark) 679, manufactured by PS Japan Co., Ltd.)
Hardening agent: t-butylperoxybenzoate (manufactured by NOF Corporation)
Mold release agent: Calcium stearate (manufactured by Tannan Chemical Co., Ltd.)

  With respect to the cured products of the resin compositions of Examples 1 to 6, the molding shrinkage, the coefficient of linear expansion, the specific gravity, and the precision abradability were evaluated by the methods described below. The evaluation results are shown in Table 1.

(1) Molding shrinkage ratio Shrinkage specified in JIS K6911 5.7 by performing compression molding (a compression molding machine made by Techno Marsichi Co., Ltd.) under the conditions of molding temperature 150 ° C., injection pressure 30 MPa, molding time 3 minutes A disc is produced, and the molding shrinkage is calculated according to JIS K6911 5.7.

(2) Linear expansion coefficient Using the obtained resin composition, a molded article is produced with a mold temperature of 150 ° C., a curing time of 180 seconds, a press pressure of 7 MPa and a mold size (80 mm × 10 mm × thickness 4 mm) Cut out a test piece of 20 mm × 4 mm × thickness 4 mm. Using the TMA 8310 (manufactured by Rigaku Corporation), the obtained test piece was heated at a temperature elevation rate of 3 ° C./min. The temperature is raised to 160 ° C. under the following conditions, and the linear expansion coefficient is measured.

(3) Specific gravity By performing compression molding (compression molding machine manufactured by Technomarsichi Co., Ltd.) under conditions of molding temperature 150 ° C., injection pressure 7 MPa and molding time 3 minutes, a contraction disk defined in JIS K6911 5.7 is obtained. After production, a test piece is cut out and the specific gravity is measured in accordance with JIS K6911 5.28.

(4) Precision abrasiveness (appearance evaluation)
Transfer molding (transfer molding machine made by Technomarsity Co., Ltd.) under the conditions of molding temperature 150 ° C., injection pressure 5 MPa, molding time 1 minute, transfer molded product (disk shape, diameter 117 mm, thickness 3 mm (uniform) ) Was produced. The surface of the molded product is roughened by cutting a thickness of about 50 μm from the surface with a flat polisher (manufactured by Malteau Co., Ltd.), and a pocket for holding the abrasive is exposed to the surface.
The surface is observed in a state in which a diamond slurry (made by Nanofactor Co., Ltd., average particle diameter 45 μm) is allowed to conform, and it is observed whether diamond particles are uniformly present in each pocket (holding portion). The number of pocket holes present in 1 mm square is measured with a microscope (VH-7000 type manufactured by Keyence Corporation). Furthermore, the hole diameter of the pocket is observed (N = 30) with a microscope (VH-7000 type manufactured by Keyence Corporation), and the average and standard deviation of the hole diameter of the pocket are calculated.

  As shown in Table 1, it has been confirmed that the cured products of the resin compositions of Examples 1 to 6 have good molding shrinkage and linear expansion coefficient of the resin composition. Moreover, the hardened | cured material of the resin composition of Examples 1-6 had the uniform size distribution of the diameter of the hole of a pocket. The hardened | cured material of the resin composition of Examples 1-6 had the uniform size distribution of the diameter of the hole of a pocket, and the diamond particle was accommodated uniformly. Therefore, the hardened | cured material of the resin composition of Examples 1-6 can be grind | polished precisely.

  In particular, the embodiment in which the content of the hollow body (D) is 20 to 40 parts by mass with respect to 100 parts by mass in total of (A) unsaturated polyester resin, (B) ethylenic unsaturated compound, and (C) inorganic filler The cured products of the resin compositions 1 to 4 have a good balance of molding shrinkage, linear expansion coefficient, and the number of holes in the pocket, and are suitable for precision polishing.

Claims (10)

  A polishing pad characterized by being a cured product of a resin composition comprising (A) unsaturated polyester resin, (B) an ethylenically unsaturated compound, (C) an inorganic filler, and (D) a hollow body. Abrasive holding material.   The said resin composition does not contain an inorganic fiber, The abrasive | polishing agent holding material for polishing pads of Claim 1 characterized by the above-mentioned.   The resin composition comprises 10 to 50 parts of the hollow body (D) per 100 parts by mass of the (A) unsaturated polyester resin, (B) ethylenic unsaturated compound, and (C) inorganic filler. The abrasive holding material for a polishing pad according to claim 1 or 2, comprising a mass part.   The said resin composition contains 80-100 mass parts of said (B) ethylenic unsaturated compounds with respect to 100 mass parts of said (A) unsaturated polyester resin, It is characterized by the above-mentioned. An abrasive holding material for a polishing pad according to one aspect.   The abrasives holding material for polishing pads as described in any one of Claims 1-4 whose weight average molecular weights of said (A) unsaturated polyester resin are 6,000-35,000.   The polishing according to any one of claims 1 to 5, wherein the hollow body (D) is at least one selected from a glass balloon, a silica balloon, an alumina balloon, a ceramic balloon, and a shirasu balloon. Abrasive holding material for pads.   The polishing agent holding material for a polishing pad according to claim 6, wherein the hollow body (D) is a glass balloon.   The (C) inorganic filler is at least one selected from aluminum hydroxide, barium sulfate, talc, kaolin, calcium sulfate, calcium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, calcium hydroxide and calcium oxide The abrasives holding material for polishing pads as described in any one of the Claims 1-7 characterized by the above-mentioned.   (A) unsaturated polyester resin, (B) ethylenic unsaturated compound, (C) inorganic filler, and (D) hollow body, containing no inorganic fiber, (A) unsaturated polyester resin The resin composition which contains 10-50 mass parts of said (D) hollow bodies with respect to a total of 100 mass parts of (B) ethylenically unsaturated compound and (C) inorganic filler.   Molding and curing a resin composition containing (A) unsaturated polyester resin, (B) ethylenically unsaturated compound, (C) inorganic filler, and (D) hollow body, and a cured resin A method for producing an abrasives holding material for a polishing pad, comprising scraping the surface of the composition to make it come out.