Polishing pad adhesive, double-sided adhesive sheet for polishing pad, multi-layer polishing pad and single-layer polishing pad

Abstract

To provide a double-sided adhesive sheet which can develop high adhesive strength in a short time after application even when applied near room temperature (for example, 23°C) and can maintain a high level of adhesive strength even when immersed in an acidic aqueous solution or an alkaline aqueous solution.SOLUTION: There is provided a polishing pad adhesive containing an acrylic copolymer (A), a synthetic rubber (B) and a curing agent (C). The polishing pad adhesive preferably contains 0.05 to 20 pts.mass of the synthetic rubber (B) based on 100 pts.mass of the acrylic copolymer (A).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a double-sided adhesive sheet for a polishing pad used when polishing objects to be polished such as silicon wafers, glass (for liquid crystals, tempered), and hard disks. The present invention also relates to an adhesive for a polishing pad for forming the double-sided adhesive sheet for a polishing pad.

Background Art

[0002] Conventionally, glass for liquid crystal displays, substrates for hard disks, optical lenses, silicon wafers, integrated circuits, etc. have been polished using polishing pads and the like. Polishing pads include multi-layer types and single-layer types. The multi-layer type polishing pad is one in which a top pad and a cushion layer are bonded together by a double-sided adhesive sheet or a double-sided adhesive tape for forming a polishing pad. The multi-layer type polishing pad or the single-layer type polishing pad, that is, the top pad, is fixed to the surface plate by a double-sided adhesive sheet or a double-sided adhesive tape for fixing the polishing pad. For the double-sided adhesive sheet or the double-sided adhesive tape for forming the multi-layer type polishing pad, it is required that the top pad does not peel off from the cushion layer during polishing. For the double-sided adhesive sheet or the double-sided adhesive tape for fixing the polishing pad to fix the polishing pad to the surface plate, it is required that the polishing pad does not peel off from the surface plate during polishing. Further, since an acidic or alkaline slurry is used in the polishing process, acid resistance and alkali resistance are required for any adhesive sheet or adhesive tape.

[0003] Patent Document 1 describes a double-sided adhesive tape for fixing a polishing member, which has a heat adhesive layer on one surface of a base material and an adhesive layer on the other surface, and the heat adhesive layer is preferably composed of a type (heat-melting type adhesive) that adheres after heating and melting and then cooling and solidifying. Specifically, it is described that a heat adhesive layer for a polishing member formed using a heat-melting type adhesive was thermocompression-bonded to an adherend at 50°C, and after leaving it in an environment of 23°C for 30 minutes, the adhesive strength was measured. In addition, Patent Document 2 describes the use of an adhesive containing an acrylic copolymer (A), a liquid xylene-based resin (B), and an isocyanate curing agent (C) as an adhesive sheet for bonding an adhesive sheet to a polishing pad without heat lamination or hot pressing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The hot-melt adhesive as described in Patent Document 1 is preferable in that it melts when heated, and after the adherends are overlapped, it solidifies promptly when the heat source is removed and the adhesion is completed in a short time, and it is likely to exhibit a relatively large adhesive force (i.e., peel force). However, when attaching a double-sided adhesive sheet to a polishing pad as the adherend, warping or undulating occurs in the polishing pad when attaching at a high temperature, and as a result, there is a problem that the polishing accuracy decreases. Attaching at a high temperature also causes an increase in environmental load and cost. Therefore, at the time of the invention described in Patent Document 1, adhesion at 50°C was aimed for. However, in recent years, adhesion at a lower temperature has been desired.

[0006] The adhesive sheet described in Patent Document 2 is excellent in that it can exhibit a large adhesive force even when the adhesive sheet is bonded to a polishing pad without heat lamination or hot pressing, and can maintain the adhesive force at a high level even when immersed in an acidic aqueous solution or an alkaline aqueous solution. However, in order to stably exhibit a large adhesive force, it took about 24 hours after adhesion. In order to quickly proceed with quality inspection and shipping judgment after adhesion, an adhesive for a polishing pad that stably exhibits an adhesive force as soon as possible after bonding is required.

[0007] The present invention has been made in view of such problems, and its object is to exhibit a high adhesive force in a short time after sticking even when stuck at around room temperature (for example, 23°C), and to maintain the adhesive force at a high level even when immersed in an acidic aqueous solution or an alkaline aqueous solution. To provide a double-sided adhesive sheet.

Means for Solving the Problems

[0008] [1] The present invention relates to an adhesive for a polishing pad containing an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C). It is preferable to contain 0.05 to 20 parts by mass of the synthetic rubber (B) with respect to 100 parts by mass of the acrylic copolymer (A). The present invention preferably further contains a tackifier resin.

[0009] [2] The present invention relates to a double-sided adhesive sheet for a polishing pad including a base material sheet, a first adhesive layer located on one surface of the base material sheet, and a second adhesive layer located on the other surface of the base material sheet, The first adhesive layer is an adhesive layer formed from the adhesive for a polishing pad described in [1], It is a double-sided adhesive sheet for a polishing pad of the following (1) or (2), (1) A double-sided adhesive sheet for a polishing pad for fixing a top pad to a cushion layer (2) A double-sided adhesive sheet for a polishing pad for fixing a top pad to a surface plate In the case of (1) above, the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the cushion layer, In the case of (2) above, the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the surface plate, Relates to a double-sided adhesive sheet for a polishing pad.

[0010] [3] In the present invention, on one surface of the top pad, the first adhesive layer of the double-sided adhesive sheet for a polishing pad is in contact, The present invention relates to a multi-layer polishing pad in which the second adhesive layer of a double-sided adhesive sheet for a polishing pad is in contact with one surface of a cushion layer. The double-sided adhesive sheet for a polishing pad includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The first adhesive layer is an adhesive layer formed from the adhesive for a polishing pad described in [1]. The present invention relates to a multi-layer polishing pad.

[0011] [4] The present invention relates to a single-layer polishing pad in which the first adhesive layer of a double-sided adhesive sheet for a polishing pad is in contact with one surface of a top pad. The double-sided adhesive sheet for a polishing pad includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The first adhesive layer is an adhesive layer formed from the adhesive for a polishing pad described in [1]. The present invention relates to a single-layer polishing pad. [Advantages of the Invention]

[0012] According to the present invention, even when adhered at around room temperature (for example, 23 ° C), a high adhesive force can be exhibited with respect to the top pad in a short time after adhesion, and the adhesive force can be maintained at a high level even when immersed in an acidic aqueous solution or an alkaline aqueous solution. Thus, a double-sided adhesive sheet can be provided. [Modes for Carrying Out the Invention]

[0013] [Acrylic copolymer (A)] In the present invention, the acrylic copolymer (A) is a (meth)acrylic polymer that can be synthesized using acrylic monomers. Examples of acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, (meth)acrylamide, vinyl acetate, acrylonitrile, etc., but are not limited thereto. They may be used alone or in combination of two or more. When synthesizing, polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization, or polymerization by ultraviolet irradiation can be employed. In the present invention, it is preferable to use solution polymerization, which is easy for reaction control and physical property control.

[0014] As the acrylic copolymer (A), it is preferable to contain a monomer having a carboxy group (hereinafter referred to as a carboxy group-containing monomer). It is preferable to use 0.1 to 10 parts by weight of the carboxyl group-containing monomer. When it is 0.1 part by weight or more, the crosslinking density with the curing agent is improved, resulting in increased cohesive force, making it difficult for lateral displacement to occur between the polishing pad and the adhesive surface in the polishing process, and also improving acid resistance. On the other hand, when it is 10 parts by weight or less, the crosslinking density with the curing agent does not become excessive, so the anchoring property to the top pad increases, making it difficult for peeling to occur between the top pad and the adhesive layer in the polishing process, and also improving alkali resistance and acid resistance. From the above viewpoints, 0.5 to 8 parts by weight is more preferable.

[0015] The carboxy group-containing monomer may be any monomer having a carboxy group. Examples include (meth)acrylic acid, itaconic acid, maleic acid, etc., and (meth)acrylic acid is preferable. These monomers may be used alone or in combination of two or more.

[0016] Moreover, as the acrylic copolymer (A), it is preferable to contain a monomer having a hydroxyl group (hereinafter referred to as a hydroxyl group-containing monomer). It is preferable to use 0.01 to 1.5 parts by weight of the hydroxyl group-containing monomer. When it is 0.01 part by weight or more, the crosslinking density with the curing agent increases, and lateral displacement between the polishing pad and the adhesive surface is less likely to occur in the polishing process. When it is 1.5 parts by weight or less, the crosslinking density with the curing agent does not become excessive, so the anchoring property to the top pad increases, peeling between the top pad and the adhesive layer is less likely to occur in the polishing process, and the alkali resistance and acid resistance are improved. From the above viewpoints, 0.05 to 1 part by weight is more preferable.

[0017] Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, N-methylolacrylamide, hydroxypropyl (meth)acrylate, etc. Among these, from the viewpoint of appropriate crosslinkability with the curing agent, a hydroxyl group-containing monomer having an alkylene group with 1 to 3 carbon atoms is preferable because it can further improve the cohesive force, heat resistance, and adhesion. And 2-hydroxyethyl (meth)acrylate is more preferable. These monomers may be used alone or in combination of two or more.

[0018] In the present invention, for copolymerization, conventionally known polymerization initiators such as peroxide-based polymerization initiators and azobis-based polymerization initiators can be used. Examples of the peroxide-based polymerization initiator for organic peroxides include benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxybenzoate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, etc. Examples of the azo-based polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethylenebisobutylamidine), etc. These polymerization initiators may be used alone or in combination of two or more.

[0019] In the present invention, the polymerization average molecular weight of the acrylic copolymer (A) is preferably 300,000 to 2,000,000, more preferably 600,000 to 1,500,000. When the polymerization average molecular weight is 300,000 or more, the cohesive force increases and the heat resistance improves, or it becomes difficult for lateral displacement to occur between the polishing pad and the adhesive surface during the polishing process. On the other hand, when it is 2,000,000 or less, the cohesive force does not increase too much, so the anchoring property to the top pad increases, and it becomes difficult for peeling to occur between the top pad and the adhesive layer during the polishing process. In the present invention, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene determined by GPC measurement, and the GPC measurement conditions are as follows. Apparatus: SHIMADZU Prominence (manufactured by Shimadzu Corporation) Column: TOSOH TSK-GEL GMPWXL (manufactured by Tosoh Corporation) is used. Solvent: Tetrahydrofuran, Flow rate: 0.5 mL / min, Temperature: 40 °C, Sample concentration: 0.1 wt%, Sample injection volume: 100 μL.

[0020] <Synthetic rubber (B)> In the present invention, the synthetic rubber (B) undertakes the function of an adhesion-imparting resin. Examples of the synthetic rubber (B) include liquid rubber (B1) and styrene-based elastomer (B2). The liquid rubber (B1) is not particularly limited, but diene-based liquid rubber is preferred, and the number average molecular weight is preferably from 100 to 60,000. In the present invention, the "liquid" state of the liquid rubber (B1) means that when a sample is placed in a cylindrical container with a bottom area of 10 cm 2 and a height of 80 cm up to a height of 20 cm, and the container is tilted horizontally at room temperature (23°C), the physical property that the sample reaches one end of the upper surface of the container within 10 minutes. Examples of such liquid rubbers (B1) include, for example, polyisoprene manufactured by Kuraray Co., Ltd., LIR-30 (number average molecular weight: 28,000, viscosity at 38°C (the same applies hereinafter): 70 Pa·s), LIR-50 (number average molecular weight: 54,000, viscosity: 500 Pa·s), LIR-390 (number average molecular weight: 48,000, viscosity: 400 Pa·s), LIR-403 (number average molecular weight: 34,000, viscosity: 200 Pa·s), LIR-410 (number average molecular weight: 30,000, viscosity: 430 Pa·s); and polybutadiene manufactured by Kuraray Co., Ltd., LBR-302 (number average molecular weight: 5,500, viscosity: 0.6 Pa·s), LBR-307 (number average molecular weight: 8,000, viscosity: 1.5 Pa·s), LBR-305 (number average molecular weight: 26,000, viscosity: 40 Pa·s), LBR-352 (number average molecular weight: 9,000, viscosity: 6 Pa·s), LBR-361 (number average molecular weight: 5,500, viscosity: 5.5 Pa·s); and polybutadiene manufactured by Nippon Soda Co., Ltd., NISSO PB B-3000 (number average molecular weight: 3200, viscosity at 45°C (the same applies hereinafter): 21 Pa·s), NISSO PB B-1000 (number average molecular weight: 1200, viscosity: 1 Pa·s); and hydroxyl-terminated polybutadiene Poly bd R-45HT (number average molecular weight: 2800, viscosity at 30°C (the same applies hereinafter): 5 Pa·s) manufactured by Idemitsu Kosan Co., Ltd.; and hydrogenated isoprene polyol Epole (number average molecular weight: 2500, viscosity: 75 Pa·s) manufactured by Idemitsu Kosan Co., Ltd.; and hydroxyl-terminated polyisoprene Poly ip (number average molecular weight: 2500, viscosity: 7.5 Pa·s) manufactured by Idemitsu Kosan Co., Ltd., etc. The liquid rubber (B1) may be used alone or in combination of two or more. Incidentally, for the value of the viscosity, after measuring an appropriate amount of the sample and setting it at each temperature, the rotor and the rotation speed are appropriately selected according to the viscosity measured using a TVB-10M viscometer manufactured by Toki Sangyo Co., Ltd., and the value is the one after 1 minute from the start of the measurement.

[0021] As the styrenic elastomer (B2), a known styrenic copolymer can be preferably used, and there is no particular limitation. Specifically, styrene-butadiene-styrene copolymer (hereinafter, also simply referred to as SBS), styrene-butadiene-styrene-butadiene copolymer (hereinafter, also simply referred to as SBSB), styrene-butadiene / butylene-styrene copolymer (hereinafter, also simply referred to as SBBS), styrene-ethylene / butylene-styrene copolymer (hereinafter, also simply referred to as SEBS), styrene-ethylene / propylene-styrene copolymer (hereinafter, also simply referred to as SEPS), styrene-ethylene-ethylene / propylene-styrene copolymer (hereinafter, also simply referred to as SEEPS), styrene-isoprene-styrene block copolymer (hereinafter, also simply referred to as SIS), etc. can be mentioned. Also, the weight average molecular weight of the styrenic elastomer (B2) is preferably 20,000 to 120,000. The lower limit of the weight average molecular weight is more preferably 30,000 or more, further preferably 45,000 or more, and particularly preferably 60,000 or more. When the weight average molecular weight is 25,000 or more, the holding power of the entire adhesive layer is improved. On the other hand, the condition of the weight average molecular weight is more preferably 90,000 or less, further preferably 75,000 or less, and particularly preferably 65,000 or less. When the weight average molecular weight is 120,000 or less, deterioration of compatibility with the acrylic copolymer (A) can be avoided.

[0022] The synthetic rubber (B) is preferably 0.05 to 20 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). When it is 0.05 parts by weight or more, even when sticking at a low temperature, a high adhesive force can be exhibited with respect to the top pad in a short time after sticking, and peeling of the adhesive surface between the top pad and the cushion layer and between the top pad and the surface plate in the polishing process can be effectively prevented. When it is 20 parts by weight or less, it becomes easier to be compatible with the acrylic copolymer (A), and it becomes easier to improve the holding force. From the above viewpoints, 0.1 to 15 parts by weight is more preferable.

[0023] <Other tackifying resins> In the present invention, in addition to the above synthetic rubber (B), those generally known as tackifying resins can be used as needed within a range that does not impair the required performance. Examples of general tackifying resins include rosin-based resins such as petroleum resins, rosin esters, polymerized rosins, hydrogenated rosins, disproportionated rosins, maleic acid-modified rosins, fumaric acid-modified rosins, and rosin phenol resins; terpene-based resins such as α-pinene resins, β-pinene resins, dipentene resins, aromatic-modified terpene resins, hydrogenated terpene resins, terpene phenol resins, acid-modified terpene resins, and styrenated terpene resins. Furthermore, coumarone-indene resins, styrene-based resins, alkylphenol resins, etc. can be mentioned, but it is not limited to these, and such tackifying resins may be used in combination of two or more, and it is preferable to use a petroleum resin or its copolymer.

[0024] Examples of the petroleum resin include, but are not limited to, FTR-6100 (softening point: 100°C), FTR-6110 (softening point: 110°C), and FTR-6125 (softening point: 125°C) manufactured by Mitsui Chemicals, Petro Tack 70 (softening point: 70°C), Petro Tack 90 (softening point: 95°C), Petro Cole 120V (softening point: 120°C), Petro Cole 100T (softening point: 100°C), Petro Cole 120 (softening point: 120°C), Petro Cole 130 (softening point: 125°C), Petro Cole LX (softening point: 95°C) manufactured by Tosoh Corporation, Tohorezine 120S (softening point: 120°C) manufactured by Toho Chemical Industry Co., Ltd., Sylvares SA-85 (softening point: 85°C), Sylvares SA-100 (softening point: 100°C), Sylvares SA-120 (softening point: 120°C), Sylvares SA-140 (softening point: 140°C) manufactured by Arizona Chemical Company, and Neopolymer S (softening point: 92°C) manufactured by ENEOS Corporation. Petroleum resins with a softening point of 80°C to 150°C are preferred, and two or more of them may be used in combination.

[0025] When the petroleum resin is used in combination with the synthetic rubber (B), the anchoring property to the top pad is enhanced, peeling between the top pad and the adhesive layer is less likely to occur during the polishing process, and the alkali resistance and acid resistance are also improved. In addition, the cohesive force is improved, and lateral displacement of the adhesive surface between the top pad and the adhesive layer is less likely to occur during the polishing process.

[0026] Regarding other tackifying resins, it is preferable to use 5 to 80 parts by weight based on 100 parts by weight of the acrylic copolymer (A). When it is 5 parts by weight or more, the anchoring property to the top pad is enhanced, peeling between the top pad and the adhesive layer is less likely to occur during the polishing process, and the acid resistance and alkali resistance are improved. When it is 80 parts by weight or less, since a decrease in adhesion or cohesive force due to the tackifying resin does not occur, lateral displacement or peeling between the top pad and the adhesive layer is less likely to occur during the polishing process. From the above viewpoints, 10 to 40 parts by weight is more preferable, and 10 to 30 parts by weight is even more preferable.

[0027] <Curing agent (C)> The curing agent (C) of the present invention has a function as a crosslinking agent, and examples thereof include isocyanate-based curing agents, epoxy-based curing agents, aziridine-based curing agents, metal chelate curing agents, and the like. Examples of the isocyanate-based curing agent include, but are not particularly limited to, adducts of isocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, and hexamethylene diisocyanate with polyols such as trimethylolpropane. As the adduct, tolylene diisocyanate is preferable as the isocyanate compound, and trimethylolpropane is preferable as the polyol. Examples of the epoxy-based compound include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, and glycerin diglycidyl ether. Examples of the metal chelate compound include compounds in which polyvalent metals such as aluminum, zinc, iron, tin, titanium, antimony, magnesium, and vanadium are coordinated with acetylacetone or ethyl acetoacetate. Examples of the aziridine-based compound include, for example, N,N'-toluene-2,4-bis(1-aziridine carboxylate), N,N'-diphenylmethane-4,4'-bis(1-aziridine carboxylate), triethylenemelamine, bisisopropartoyl-1-(2-methylaziridine), or tri-1-aziridinylphosphine oxide. The above crosslinking agents may be used in combination of two or more.

[0028] The total amount of the crosslinking agent is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 8 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). When it is 0.1 part by weight or more, the crosslinking density is improved and the cohesive force is increased, and lateral displacement is less likely to occur between the top pad and the adhesive layer in the polishing process. On the other hand, when it is 10 parts by weight or less, the crosslinking density does not become excessive, so the anchoring property to the top pad is increased, and peeling between the top pad and the adhesive layer is less likely to occur in the polishing process.

[0029] <Other Additives> The pressure-sensitive adhesive of the present invention may contain various additives such as fillers, pigments, dyes, diluents, anti-aging agents, polymerization inhibitors, ultraviolet absorbers, ultraviolet stabilizers, coupling agents, etc., which are blended into known pressure-sensitive adhesive compositions as necessary, and two or more types may also be used. Further, the addition amount of the additives may be an amount that can obtain the required physical properties and is not particularly limited.

[0030] <Regarding the configuration of the adhesive sheet> The adhesive sheet of the present invention is a double-sided adhesive sheet for a polishing pad, comprising a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet, The first adhesive layer is an adhesive layer formed from the above-mentioned adhesive for a polishing pad containing an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C). It is a double-sided adhesive sheet for a polishing pad of the following (1) or (2), (1) A double-sided adhesive sheet for a polishing pad for fixing a top pad to a cushion layer (2) A double-sided adhesive sheet for a polishing pad for fixing a top pad to a surface plate In the case of (1) above, the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the cushion layer. In the case of (2) above, the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the surface plate. It is a double-sided adhesive sheet for a polishing pad. The second adhesive layer in contact with the cushion layer or the surface plate can also be formed from an adhesive containing an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C) in the same manner as the first adhesive layer, or can be formed from an acrylic adhesive, a rubber adhesive, or the like.

[0031] Examples of the base sheet in the present invention include plastic films such as polyethylene, polypropylene, polyester, polystyrene, polyethylene terephthalate (hereinafter also referred to as PET), polyvinyl chloride, polycarbonate, and cellophane, papers such as high-quality paper, kraft paper, crepe paper, and glassine paper, cloths such as woven fabrics and non-woven fabrics, foams such as urethane foam and EPDM foam, etc. Although not particularly limited thereto, a plastic film corona-treated on both sides is preferable. The thickness of the base material is preferably 5 to 300 μm, more preferably 10 to 200 μm.

[0032] The top pad, also called a polishing cloth, is a member that directly contacts the object to be polished during polishing for polishing, and examples include a hard polyurethane sheet, synthetic leather, suede, and velour. The top pad may be used as a single layer fixed to the surface plate as in the case of (2) above, or may be bonded to a cushion layer to form the outermost surface of a multi-layer type polishing pad. Examples of the cushion layer include foams and non-woven fabrics. Examples of the foam include urethane-based foams, polyethylene-based foams, and polypropylene-based foams. Examples of the non-woven fabric include those made from polyester and those made from natural products such as wool.

[0033] The double-sided adhesive sheet for a polishing pad of the present invention can be manufactured, for example, by the following methods (1) and (2). (1) A system adhesive for forming a first adhesive layer and a system adhesive for forming a second adhesive layer are respectively coated on a release liner to form a first adhesive layer and a second adhesive layer, and then the first adhesive layer and the second adhesive layer are respectively bonded to each surface of the base sheet. (2) Apply either the system adhesive for forming the first adhesive layer or the system adhesive for forming the second adhesive layer on one surface of the base sheet to form the first adhesive layer or the second adhesive layer. Separately, apply the other adhesive of either the system adhesive for forming the first adhesive layer or the system adhesive for forming the second adhesive layer on a release liner to form the other adhesive layer, and attach the other adhesive layer formed on the release liner to the surface of the base sheet on the side where the adhesive layer is not formed. Note that each adhesive layer is usually protected by a release liner until immediately before using the adhesive sheet.

[0034] The release liner has a release layer formed by applying a release agent to a base material such as paper, plastic film, synthetic paper, etc. Examples of the release agent include silicone, alkyd resin, melamine resin, fluororesin, acrylic resin, etc. The re-peelable adhesive of the present invention can obtain an effect that the peel force is less dependent on the type of the release agent. Note that the thickness of the release liner is not particularly limited, but is about 10 to 200 μm.

[0035] For applying the adhesive, known methods such as the roll coater method, comma coater method, lip coater method, die coater method, reverse coater method, silk screen method, gravure coater method, etc. can be used. After coating, it can be dried with a hot air oven, infrared heater, etc., but is not particularly limited thereto. The thickness of the adhesive layer is preferably 25 to 200 μm, more preferably 50 to 150 μm.

[0036] <Multi-layered polishing pad> The multi-layered polishing pad of the present invention is a multi-layered polishing pad in which the first adhesive layer of the double-sided adhesive sheet for polishing pad is laminated on one surface of the top pad, The double-sided adhesive sheet for polishing pad includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet, and is a double-sided adhesive sheet for polishing pad. The first adhesive layer is an adhesive layer formed from the above-mentioned adhesive for polishing pad containing an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C). The second adhesive layer is in contact with the cushion layer.

[0037] The multi-layer polishing pad of the present invention can be manufactured, for example, as follows. Peel off the release liner that had covered the first adhesive layer, and overlay the top pad on the first adhesive layer. When overlaying, special heating is not necessary, but heating is also possible. After overlaying, leave it at around room temperature for about 3 hours to develop stable peel strength. Next, peel off the release liner that had covered the second adhesive layer, and overlay the cushion layer on the second adhesive layer. When a conventional adhesive is used for forming the second adhesive layer, it is preferable to leave it at around room temperature for about 24 hours after overlaying the cushion layer on the second adhesive layer. Alternatively, first peel off the release liner that had covered the second adhesive layer, and overlay the cushion layer on the second adhesive layer. When a conventional adhesive is used for forming the second adhesive layer, it is preferable to leave it at around room temperature for about 24 hours after overlaying the cushion layer on the second adhesive layer. Next, peel off the release liner that had covered the first adhesive layer, and overlay the top pad on the first adhesive layer. When overlaying, special heating is not necessary, but heating is also possible. After overlaying, leave it at around room temperature for about 3 hours to develop stable peel strength. In addition, for forming the second adhesive layer as well, if an adhesive containing an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C) is used in the same manner as in the case of the first adhesive layer, the standing time at around room temperature after overlaying the cushion layer on the second adhesive layer can be made about 3 hours.

[0038] The other surface of the cushion layer of the multi-layer polishing pad can be attached to a surface plate, and the multi-layer polishing pad can be fixed to the surface plate. When attaching the cushion layer of the multi-layer polishing pad to the surface plate, various double-sided adhesive sheets can be used.

[0039] <Single-layer polishing pad> The double-sided adhesive sheet for a polishing pad of the present invention can also be used for forming a single-layer polishing pad. That is, the release liner covering the first adhesive layer is peeled off, and the top pad is superposed on the first adhesive layer. When superposing, special heating is not necessary, but heating can also be performed. After superposing, it is left at around room temperature for about 3 hours to form a single-layer polishing pad with stable peel strength. The second adhesive layer of the single-layer polishing pad can be pasted on the surface plate to fix the single-layer polishing pad on the surface plate. When pasting the single-layer polishing pad on the surface plate, various double-sided adhesive sheets can be used.

Example

[0040] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. In the examples, "parts" and "%" indicate parts by weight and % by weight, respectively.

[0041] (Measurement of weight average molecular weight) Measured in the same manner as the method described in the specification. (Method for measuring viscosity) Measured in the same manner as the method described in the specification. (Method for measuring softening point) The value measured in accordance with JIS K2207.

[0042] <Production Example 1> Using a reaction apparatus equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping tube, 50 parts by weight of the total amount of each monomer in Table 1, 0.03 part of perbutyl O as an initiator, and 50 parts of ethyl acetate as a solvent were charged into the reaction vessel. The total amount of the remaining monomers, 35 parts of ethyl acetate, and 0.07 part of perbutyl O were added and mixed, and the resulting solution was charged into the dropping tube. After heating the reaction vessel and confirming reflux, the monomer mixture was dropped from the dropping tube over about 1 hour, and then the reaction was continued at about 80 °C. After completion of the reaction, it was cooled and diluted with ethyl acetate to obtain a solution of acrylic copolymer A1. The non-volatile content of the solution of acrylic copolymer A1 was 47%, and the weight average molecular weight of acrylic copolymer A1 was 600,000.

[0043] <Production Examples 2 to 7> In the same manner as in Production Example 1, solutions of acrylic copolymers A2 to A7 were obtained according to the monomer formulations shown in Table 1.

[0044]

Table 1

[0045] The abbreviations in Table 1 are as follows. 2EHA: 2-ethylhexyl acrylate BA: butyl acrylate EA: ethyl acrylate VAC: vinyl acetate AA: acrylic acid 2HEA: 2-hydroxyethyl acrylate

[0046] <Example 1> As shown in Table 2, with respect to the solution containing 100 parts by weight of the acrylic copolymer A1 obtained in Production Example 1, 1.4 parts of LIR-410 (polyisoprene manufactured by Kuraray Co., Ltd., number average molecular weight 30,000, viscosity 430 Pa·s) as the liquid rubber (B1-1), 19.4 parts of Haritack PCJ (polymerized rosin ester manufactured by Harima Kasei Group Co., Ltd., softening point 123°C) as the other tackifier resin, 7.5 parts of Neopolymer S (aromatic hydrocarbon resin manufactured by ENEOS Co., Ltd., softening point 92°C), 0.5 part by weight in terms of solid content of Mytec GP-1 (ethyl acetate solution of a tolylene diisocyanate trimethylolpropane adduct with a non-volatile content of 37.5% manufactured by Mitsubishi Chemical Corporation), 0.4 part of an antioxidant, and an appropriate amount of ethyl acetate were blended to obtain an adhesive with a non-volatile content of 47%. The numerical values in Table 2 represent parts.

[0047] Next, the obtained adhesive was applied onto a commercially available release liner using a comma coater so that the thickness of the dried adhesive layer became 80 μm, dried in a drying oven at 100 °C for 2 minutes to remove the solvent, and then laminated onto one surface of a 25-μm PET film. Separately, in the same manner using a comma coater, it was applied onto a commercially available release liner so that the thickness of the dried adhesive layer became 80 μm, dried in a drying oven at 100 °C for 2 minutes to remove the solvent, and then laminated onto the other surface of a 25-μm PET film to obtain a double-sided adhesive sheet with a total thickness of 185 μm, and the performance of the double-sided adhesive sheet was evaluated according to the method described below.

[0048] <Examples 2 to 13> As shown in Table 2, adhesives and double-sided adhesive sheets were obtained in the same manner as in Example 1 except that the type of synthetic rubber (B) was changed, and the performance of the double-sided adhesive sheets was evaluated.

[0049] <Examples 14 to 19> As shown in Table 3, adhesives and double-sided adhesive sheets were obtained in the same manner as in Example 1 except that the type of acrylic copolymer was changed, and the performance of the double-sided adhesive sheets was evaluated.

[0050] <Examples 20 to 23> As shown in Table 3, adhesives and double-sided adhesive sheets were obtained in the same manner as in Example 1 except that the amount of liquid rubber (B1-1) was changed, and the performance of the double-sided adhesive sheets was evaluated.

[0051] <Example 24> As shown in Table 3, adhesives and double-sided adhesive sheets were obtained in the same manner as in Example 1 except that no antioxidant was used, and the performance of the double-sided adhesive sheets was evaluated.

[0052] <Examples 25 to 31> As shown in Table 4, adhesives and double-sided adhesive sheets were obtained in the same manner as in Example 1 except that the type and amount of other tackifying resins were changed, and the performance of the double-sided adhesive sheets was evaluated.

[0053] <Examples 32 to 36> As shown in Table 4, an adhesive and a double-sided adhesive sheet were obtained in the same manner as in Example 1 except that the type and amount of the curing agent (C) were changed, and the performance of the double-sided adhesive sheet was evaluated.

[0054] <Comparative Examples 1-2> As shown in Table 4, an adhesive and a double-sided adhesive sheet were obtained in the same manner as in Example 1 except that synthetic rubber (B) was not used in Comparative Example 1 and the curing agent (C) was not used in Comparative Example 2, and the performance of the double-sided adhesive sheet was evaluated.

[0055] The abbreviations in Tables 2 to 4 are as follows. Synthetic rubber (B) B1-1: Polyisoprene manufactured by Kuraray Co., Ltd. LIR-410, number average molecular weight: 30,000, viscosity: 430 Pa·s B1-2: Polyisoprene manufactured by Kuraray Co., Ltd. LIR-390, number average molecular weight: 48,000, viscosity: 400 Pa·s B1-3: Polyisoprene manufactured by Kuraray Co., Ltd. LIR-30, number average molecular weight: 28,000, viscosity: 70 Pa·s B1-4: Polyisoprene manufactured by Kuraray Co., Ltd. LIR-403, number average molecular weight: 34,000, viscosity: 200 Pa·s B1-5: Polybutadiene manufactured by Kuraray Co., Ltd. LBR-305, number average molecular weight: 26,000, viscosity: 40 Pa·s B1-6: Polybutadiene manufactured by Kuraray Co., Ltd. LBR-352, number average molecular weight: 9,000, viscosity: 6 Pa·s B1-7: Polybutadiene manufactured by Kuraray Co., Ltd. LBR-361, number average molecular weight: 5,500, viscosity: 5.5 Pa·s B1-8: Polybutadiene manufactured by Nippon Soda Co., Ltd. NISSO PB B-3000, number average molecular weight 3200, viscosity 21 Pa·s B1-9: Polybutadiene manufactured by Nippon Soda Co., Ltd. NISSO PB B-1000, number average molecular weight 1200, viscosity 1 Pa·s B1-10: Hydroxyl-terminated polybutadiene manufactured by Idemitsu Kosan Co., Ltd. Poly bd R-45HT, number average molecular weight 2800, viscosity 5 Pa·s B1-11: Hydrogenated isoprene polyol manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight 2500, viscosity 75 Pa·s B1-12: Hydroxyl-terminated polyisoprene manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight 2500, viscosity 7.5 Pa·s B2: G-1650 (styrene-ethylene / butylene-styrene block copolymer manufactured by Clayton, weight average molecular weight 96,000) Note that for B1-1 to B1-12, when the sample is placed in a cylindrical container with a bottom area of 10 cm 2 and a height of 80 cm up to a height of 20 cm, and the container is tilted horizontally at room temperature (23°C), the sample reaches one end of the upper surface of the container within 10 minutes.

[0056] Hardener (C) C1: Ethyl acetate solution with a non-volatile content of 37.5% of a tolylene diisocyanate trimethylolpropane adduct manufactured by Mitsubishi Chemical Corporation, Mytec GP-105A C2: Toluene / IPA mixed solution with a non-volatile content of 5% of a polyfunctional epoxy resin of Mitsubishi Gas Chemical Company, Tetrad X C3: Toluene / IPA mixed solution with a non-volatile content of 5% of a polyfunctional aziridine resin manufactured by Nippon Shokubai Co., Ltd., Chemitec PZ33

[0057] (Other tackifying resins D) D1: Polymerized rosin ester manufactured by Harima Kasei Group, Haritack PCJ (softening point 123°C) D2: Aromatic hydrocarbon resin manufactured by ENEOS Corporation, Neopolymer S (softening point 92°C) D3: Hydrogenated petroleum resin manufactured by Arakawa Chemical Industries, Ltd., Alcon P100 (softening point 100°C) D4: Special rosin ester manufactured by Arakawa Chemical Industries, Ltd., Super Ester A125 (softening point 125°C) D5: Hydrogenated alicyclic resin manufactured by ExxonMobil Corporation, ECR5380 (softening point 86°C)

[0058] [Evaluation method] [Preparation of test pieces] Samples measuring 10 mm in length and 25 mm in width were cut out from the double-sided adhesive sheets obtained in each example and each comparative example, and the release liners were peeled off at three different ambient temperatures (23 °C, 50 °C, 100 °C). A top pad (commercially available rigid urethane pad) was placed on the exposed adhesive layer and pressed once back and forth with a 2 kg roll. In the case of 23 °C, the sample was left in an environment of 23 °C for 3 hours or 24 hours to prepare a test piece for measurement. In the cases of 50 °C and 100 °C, immediately after pressing, the sample was transferred to an ambient temperature of 23 °C and left in an environment of 23 °C - 50% for 3 hours to prepare a test piece for measurement.

[0059] <<Initial>> For the test pieces left in an environment of 23 °C - 50% for a predetermined time, a tensile test was immediately used in the same environment, and in accordance with the measurement method of JIS Z1528, the peel strength at a peel rate of 300 / min. and a peel angle of 180 degrees was measured.

[0060] <<After alkali immersion>> The test pieces left in an environment of 23 °C - 50% for 3 hours were immersed in an aqueous solution at 40 °C adjusted to pH 11.5 using sodium hydroxide for 24 hours. Then, the samples were taken out from the aqueous solution, washed with water, and the peel strength at a peel angle of 180 degrees was measured in the same manner as in the initial case.

[0061] <<After acid immersion>> The test pieces left in an environment of 23 °C - 50% for a predetermined 3 hours were immersed in an aqueous solution at 40 °C adjusted to pH 1.5 using sulfuric acid for 24 hours. Then, the samples were taken out from the aqueous solution, washed with water, and the peel strength at a peel angle of 180 degrees was measured in the same manner as in the initial case.

[0062]

Table 2

[0063]

Table 3

[0064]

Table 4

Claims

1. An adhesive for a polishing pad, comprising an acrylic copolymer (A), a synthetic rubber (B), and a curing agent (C).

2. The adhesive for a polishing pad according to claim 1, comprising 0.05 to 20 parts by mass of a synthetic rubber (B) with respect to 100 parts by mass of the acrylic copolymer (A).

3. The adhesive for a polishing pad according to claim 1 or 2, further comprising an adhesion - promoting resin.

4. A double - sided adhesive sheet for a polishing pad, comprising a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet, wherein the first adhesive layer is an adhesive layer formed from the adhesive for a polishing pad according to claim 1 or 2, and is a double - sided adhesive sheet for a polishing pad of the following (1) or (2), (1) A double - sided adhesive sheet for a polishing pad for fixing a top pad to a cushion layer (2) A double - sided adhesive sheet for a polishing pad for fixing a top pad to a surface plate In the case of (1), the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the cushion layer, In the case of (2), the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the surface plate, A double - sided adhesive sheet for a polishing pad.

5. A double - sided adhesive sheet for a polishing pad, comprising a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet, wherein the first adhesive layer is an adhesive layer formed from the adhesive for a polishing pad according to claim 3, and is a double - sided adhesive sheet for a polishing pad of the following (1) or (2), (1) A double - sided adhesive sheet for a polishing pad for fixing a top pad to a cushion layer (2) A double - sided adhesive sheet for a polishing pad for fixing a top pad to a surface plate In the case of (1), the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the cushion layer, In the case of (2), the first adhesive layer is in contact with the top pad, and the second adhesive layer is in contact with the surface plate, A double - sided adhesive sheet for a polishing pad.

6. A multi - layer polishing pad in which a first adhesive layer of a double - sided adhesive sheet for a polishing pad is in contact with one surface of a top pad, and a second adhesive layer of the double - sided adhesive sheet for a polishing pad is in contact with one surface of a cushion layer, wherein the double - sided adhesive sheet for a polishing pad is a double - sided adhesive sheet for a polishing pad comprising a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The multi-layer polishing pad, wherein the first adhesive layer is an adhesive layer formed from the polishing pad adhesive according to claim 1 or 2.

7. A multi-layer polishing pad, wherein one surface of the top pad is in contact with the first adhesive layer of the double-sided adhesive sheet for polishing pads, and one surface of the cushion layer is in contact with the second adhesive layer of the double-sided adhesive sheet for polishing pads. The double-sided adhesive sheet for polishing pads includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The multi-layer polishing pad, wherein the first adhesive layer is an adhesive layer formed from the polishing pad adhesive according to claim 3.

8. A single-layer polishing pad, wherein one surface of the top pad is in contact with the first adhesive layer of the double-sided adhesive sheet for polishing pads. The double-sided adhesive sheet for polishing pads includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The single-layer polishing pad, wherein the first adhesive layer is an adhesive layer formed from the polishing pad adhesive according to claim 1 or 2.

9. A single-layer polishing pad, wherein one surface of the top pad is in contact with the first adhesive layer of the double-sided adhesive sheet for polishing pads. The double-sided adhesive sheet for polishing pads includes a base sheet, a first adhesive layer located on one surface of the base sheet, and a second adhesive layer located on the other surface of the base sheet. The single-layer polishing pad, wherein the first adhesive layer is an adhesive layer formed from the polishing pad adhesive according to claim 3. ​

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