JP2009241224A - Laminate sheet for fabrication of polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate sheet for fabrication of a polishing pad, the sheet being able to be cut easily with no use of any cutting tool. <P>SOLUTION: The laminate sheet 8 for fabrication of a polishing pad is structured so that a polishing layer 1 is provided on one surface of a base material layer 2, and on the other surface, a sticky sheet 7 consisting of a sticky substance layer 5 and a releasing sheet 6 is provided, wherein the polishing layer consists of a foam body of thermo-setting polyurethane having continuous bubbles approximately in a spherical shape and not containing abrasive grains. The polishing layer is in self-adhesion to the base material layer, and the laminate sheet is furnished with a cutoff line 4, at least penetrating the base material layer. The tearing force of the laminate consisting of the polishing layer and the base material layer in the position of the cutoff line is 1-4 N, and in the polishing layer, the product of the tensile strength and the thickness in the position of the cutoff line is 2-10 MPamm, and the base material layer has a greater tensile strength than the polishing layer, in which the product of the tensile strength and the thickness is 10-40 MPamm, while the sticky sheet is free of cutoff line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is for producing a polishing pad (for rough polishing or finish polishing) used for polishing surfaces of optical materials such as lenses and reflection mirrors, silicon wafers, glass substrates for hard disks, and aluminum substrates. The present invention relates to a laminated sheet. The polishing pad of the present invention is suitably used as a polishing pad for finishing.

  In general, mirror polishing of semiconductor wafers such as silicon wafers, lenses, and glass substrates mainly involves rough polishing for the purpose of adjusting flatness and in-plane uniformity, improvement of surface roughness, and removal of scratches. There is intended finish polishing.

  The finish polishing is usually performed by attaching a suede-like artificial leather made of soft urethane foam on a rotatable surface plate and supplying an abrasive containing colloidal silica to an alkali-based aqueous solution. (Patent Document 1).

  In addition to the above, the following have been proposed as polishing pads used for finish polishing.

  A suede-like finish polishing pad consisting of a nap layer in which polyurethane foam is formed with a number of elongated fine holes (nap) formed in the thickness direction using a foaming agent and a base fabric that reinforces the nap layer has been proposed. (Patent Document 2).

  Moreover, it is laminated | stacked on the back surface side of the surface layer whose thickness is 0.2-2.0 mm, and an elastic compressibility is 50-4%, and this surface layer is 0.2-2 mm, It is laminated | stacked on the back surface side of the intermediate | middle support layer whose elastic compressibility is 2-0.1%, and this intermediate | middle support layer, thickness is 0.15-2.0 mm, and elastic compressibility is 50-4%. A polishing cloth having a back surface layer is proposed (Patent Document 3).

  Further, a polishing cloth for finish polishing that is suede-like and has a surface roughness of 5 μm or less in arithmetic mean roughness (Ra) has been proposed (Patent Document 4).

  Also, a polishing cloth for finishing polishing comprising a base material part and a surface layer (nap layer) formed on the base material part, wherein the surface layer contains a polyvinyl halide or a vinyl halide copolymer. Has been proposed (Patent Document 5).

  Conventional polishing pads have been manufactured by a so-called wet curing method. The wet curing method is a method in which a urethane resin solution in which a urethane resin is dissolved in a water-soluble organic solvent such as dimethylformamide is applied onto a substrate, which is treated in water and wet solidified to form a porous silver surface layer. The surface layer (nap layer) is formed by grinding the surface of the silver surface layer after washing and drying. For example, in Patent Document 6, a finishing polishing cloth having a substantially spherical hole having an average diameter of 1 to 30 μm is manufactured by a wet curing method.

  However, the conventional polishing pad has a problem that the durability is low and the planarization characteristics are gradually deteriorated because the bubbles have an elongated structure or the mechanical strength of the surface layer material itself is low.

  On the other hand, such a polishing pad is used after being cut out from a cloth-like sheet into an appropriate size using a blade. However, there has been a problem that metal is mixed into the polishing pad in the cutting process or that the cutting process is complicated. Therefore, development of a simple cutting method has been desired.

  Patent Document 7 proposes a method of providing a cutting line for cutting a polishing sheet into a predetermined shape.

  Further, Patent Document 8 proposes a method of forming a cut line in the polishing layer in order to easily peel the polishing pad attached to the polishing table of the CMP apparatus.

JP 2003-37089 A JP 2003-1000068 A1 JP 2002-307293 A JP 2004-291155 A JP 2004-335713 A JP 2006-75914 A Utility Model Registration No. 3051625 Specification Japanese Patent Laid-Open No. 2006-100347

  An object of this invention is to provide the lamination sheet for polishing pad preparation which can be cut | disconnected easily, without using a cutter.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following laminated sheet for producing a polishing pad, and have completed the present invention.

That is, the present invention provides a polishing pad-prepared laminated sheet in which a polishing layer is provided on one side of a base material layer, and an adhesive sheet comprising an adhesive layer and a release sheet is provided on the other side.
The polishing layer has a substantially spherical open cell, and consists of a thermosetting polyurethane foam containing no abrasive grains,
The polishing layer is self-adhering to the base material layer,
The laminated sheet is provided with a tear line penetrating at least the base material layer,
The tearing force of the laminate composed of the polishing layer and the base material layer at the cut line position is 1 to 4 N,
The polishing layer has a product of tensile strength and thickness at the cut line position of 2 to 10 MPa · mm,
The base material layer has a tensile strength larger than that of the polishing layer, and the product of the tensile strength and the thickness is 10 to 40 MPa · mm,
The adhesive sheet is not provided with a cut line,
The present invention relates to a laminated sheet for producing a polishing pad.

  A laminated sheet for polishing pad preparation (hereinafter referred to as a laminated sheet) is provided with a tear line penetrating at least the base material layer, and the tearing force of the laminate composed of the polishing layer and the base material layer at the tear line position is adjusted to 1 to 4N. The product of the tensile strength and thickness of the polishing layer at the cut line position is adjusted to 2 to 10 MPa · mm, and the tensile strength is larger than the tensile strength of the polishing layer and the product of tensile strength and thickness is 10 to 40 MPa. -By using the base material layer which is mm, the laminated sheet can be easily cut by hand to separate the polishing pad due to the edge effect of the base material layer.

  When the tearing force of the laminate composed of the polishing layer and the base material layer at the cut line position is less than 1N, it becomes difficult to bond the pressure sensitive adhesive sheet to the other surface of the base material layer with high accuracy, and when it exceeds 4N. Makes it difficult to cut the laminated sheet by hand.

  When the product of the tensile strength and thickness of the polishing layer at the cut line position is less than 2 MPa · mm, the polishing layer is easily broken and the lamination process becomes difficult. It becomes difficult to cut.

  When the product of tensile strength and thickness of the base material layer is less than 10 MPa · mm, it is difficult to accurately cut the laminated sheet along the cut line by hand because the edge effect of the base material layer cannot be obtained sufficiently. become. On the other hand, if it exceeds 40 MPa · mm, the repulsive force becomes large when the laminated sheet is rolled up, and a large winding force is required to wind up densely. An increase in the winding force is not preferable because a change in thickness is likely to occur in the polishing layer.

  It is necessary that the adhesive sheet of the laminated sheet is not provided with a cut line. Thereby, when the laminated sheet is rolled up, it is possible to prevent the unevenness from being transferred to the surface of the polishing layer due to the cut. Moreover, since the adhesive sheet can relieve the tension load on the polishing layer, deformation of the polishing layer can be prevented.

  Further, the polishing layer needs to be self-adhering to the base material layer. Thereby, it can prevent that a grinding | polishing layer and a base material layer peel during grinding | polishing.

  The tear line may be provided up to the inside of the polishing layer in order to adjust the tearing force of the laminate to the above range.

  The cut line may be provided continuously or intermittently (discontinuously).

  In addition, the conventional polishing pad for finishing has a long and slender structure, or the mechanical strength of the material of the polishing layer itself is low. It is thought that it becomes poor. On the other hand, the durability of the polishing layer can be improved by forming the polishing layer with a thermosetting polyurethane foam having substantially spherical open cells as in the present invention. Therefore, when the polishing pad of the present invention is used, the planarization characteristics can be maintained high for a long time. Here, the substantially spherical shape means a spherical shape and an elliptical shape. Oval and spherical bubbles are those having a major axis L to minor axis S ratio (L / S) of 5 or less, preferably 3 or less, more preferably 1.5 or less.

  The thermosetting polyurethane foam of the present invention needs to contain no abrasive grains. When the thermosetting polyurethane foam contains abrasive grains, the interface between the polyurethane and the abrasive grains becomes a crack starting point at the time of cutting, so that the laminated sheet can be accurately cut along the cut line. However, it is preferable not to use abrasive grains in the polishing layer because they cause scratches. In the present invention, a thermosetting polyurethane foam having open cells is used as a material for forming the polishing layer. Since the micropores of the open cells serve as crack initiation points, the laminated sheet is accurately cut along the cut line. be able to.

  The laminated sheet for producing a polishing pad of the present invention comprises a polishing layer, a base material layer, and an adhesive sheet. The polishing layer is made of a thermosetting polyurethane foam having substantially spherical open cells and containing no abrasive grains.

  Polyurethane resin is excellent in abrasion resistance, and it is possible to easily obtain polymers having desired physical properties by changing the raw material composition. Also, it is easy to form almost spherical fine bubbles by mechanical foaming (including mechanical flossing). Since it can be formed, it is a preferable material for forming the polishing layer.

  The polyurethane resin is composed of an isocyanate component and an active hydrogen group-containing compound (high molecular weight polyol, low molecular weight polyol, low molecular weight polyamine, alcohol amine, etc.).

  As the isocyanate component, a known compound in the field of polyurethane can be used without particular limitation. For example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, polymeric MDI, carbodiimide-modified MDI (for example, commercial products) Name Millionate MTL, manufactured by Nippon Polyurethane Industry), 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, and other aromatic diisocyanates, ethylene diisocyanate, 2,2 1,4-trimethylhexamethylene diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, 1,4-cyclohexane San diisocyanate, cyclohexane diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, isophorone diisocyanate, and cycloaliphatic diisocyanates such as norbornane diisocyanate. These may be used alone or in combination of two or more.

  As the isocyanate component, a trifunctional or higher polyfunctional polyisocyanate compound can be used in addition to the diisocyanate compound. As a polyfunctional isocyanate compound, a series of diisocyanate adduct compounds are commercially available as Desmodur-N (manufactured by Bayer) or trade name Duranate (manufactured by Asahi Kasei Kogyo Co., Ltd.).

  Of the above isocyanate components, carbodiimide-modified MDI is preferably used.

  Examples of the high molecular weight polyol include those usually used in the technical field of polyurethane. Examples include polyether polyols typified by polytetramethylene ether glycol, polyethylene glycol, etc., polyester polyols typified by polybutylene adipate, polycaprolactone polyols, reactants of polyester glycols such as polycaprolactone and alkylene carbonate, etc. Polyester polycarbonate polyol obtained by reacting ethylene carbonate with polyhydric alcohol and then reacting the obtained reaction mixture with organic dicarboxylic acid, polycarbonate polyol obtained by transesterification of polyhydroxyl compound and aryl carbonate And polymer polyol which is a polyether polyol in which polymer particles are dispersed.These may be used alone or in combination of two or more.

  Among the high molecular weight polyols, it is preferable to use a high molecular weight polyol having a hydroxyl value of 100 to 250 mgKOH / g. The hydroxyl value is more preferably 100 to 150 mgKOH / g. When the hydroxyl value is less than 100 mgKOH / g, the amount of polyurethane hard segments tends to decrease and the durability tends to decrease. When the hydroxyl value exceeds 250 mgKOH / g, the degree of crosslinking of the polyurethane foam becomes too high. Tend to be brittle.

  The high molecular weight polyol is preferably contained in the active hydrogen group-containing compound in an amount of 70 to 95% by weight, more preferably 80 to 95% by weight. By using a specific amount of the high molecular weight polyol, the cell membrane is easily broken, and an open cell structure is easily formed.

  The number average molecular weight of the high molecular weight polyol is not particularly limited, but is preferably 500 to 3500 from the viewpoint of the elastic properties of the resulting polyurethane. If the number average molecular weight is less than 500, a polyurethane using the number average molecular weight does not have sufficient elastic properties and tends to be a brittle polymer. Therefore, the polishing layer made of this polyurethane foam becomes too hard, and scratches are likely to occur on the surface of the object to be polished. On the other hand, when the number average molecular weight exceeds 3500, polyurethane using the same becomes too soft. Therefore, the durability of the polishing layer made of this polyurethane foam tends to deteriorate.

  Along with high molecular weight polyol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, tri Methylolpropane, glycerin, 1,2,6-hexanetriol, pentaerythritol, tetramethylolcyclohexane, methyl glucoside, sorbitol, mannitol, dulcitol, sucrose, 2,2,6,6-tetrakis (hydroxymethyl) cyclo Low molecular weight polyols such as xanol, diethanolamine, N-methyldiethanolamine, and triethanolamine; low molecular weight polyamines such as ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine; monoethanolamine, 2- (2-aminoethylamino) ethanol , And low molecular weight components such as alcohol amines such as monopropanolamine may be used in combination. These low molecular weight components may be used alone or in combination of two or more.

  Among these, it is preferable to use a low molecular weight component having a hydroxyl value or an amine value of 1000 to 2000 mgKOH / g. The hydroxyl value or amine value is more preferably 1000 to 1500 mgKOH / g. When the hydroxyl value or the amine value is less than 1000 mgKOH / g, the effect of improving the formation of open cells tends to be insufficient. On the other hand, when the hydroxyl value or amine value exceeds 2000 mgKOH / g, scratches tend to occur on the wafer surface. In particular, it is preferable to use diethylene glycol, 1,2-propylene glycol, 1,3-butanediol, or 1,4-butanediol.

  Further, it is preferable to use a low molecular weight component having 3 functional groups having a hydroxyl group and / or an amino group. Examples of the low molecular weight component include trimethylolpropane, glycerin, diethanolamine, triethanolamine, and 1,2,6-hexanetriol.

  In order to make the polyurethane foam into an open cell structure, the low molecular weight component is preferably contained in the active hydrogen group-containing compound in a total amount of 2 to 15% by weight, more preferably 2 to 10% by weight. By using a specific amount of the low molecular weight polyol or the like, not only the bubble film is easily broken and it becomes easy to form open cells, but also the mechanical properties of the polyurethane foam are improved.

  When the polyurethane resin is produced by the prepolymer method, a chain extender is used for curing the isocyanate-terminated prepolymer. The chain extender is an organic compound having at least two active hydrogen groups, and examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH). Specifically, 4,4′-methylenebis (o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 4,4′-methylenebis (2,3-dichloroaniline), 3,5 -Bis (methylthio) -2,4-toluenediamine, 3,5-bis (methylthio) -2,6-toluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2 , 6-diamine, trimethylene glycol-di-p-aminobenzoate, 1,2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyl Diphenylmethane, N, N′-di-sec-butyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-4,4′-diaminodiphenylmethane, m-xyl Polyamines exemplified by N-diamine, N, N′-di-sec-butyl-p-phenylenediamine, m-phenylenediamine, and p-xylylenediamine, or the low molecular weight polyols and low molecular weight polyamines mentioned above. Can be mentioned. These may be used alone or in combination of two or more.

  The ratio of the isocyanate component, the polyol component, and the chain extender can be variously changed depending on the molecular weight of each, the desired physical properties of the polyurethane foam, and the like. In order to obtain a foam having desired characteristics, the number of isocyanate groups of the isocyanate component relative to the total number of active hydrogen groups (hydroxyl group + amino group) of the polyol component and the chain extender is 0.80 to 1.20. Preferably, it is 0.99 to 1.15. When the number of isocyanate groups is outside the above range, curing failure occurs and the required specific gravity, hardness, compression ratio, etc. tend not to be obtained.

  The polyurethane resin can be produced by applying a known urethanization technique such as a melting method or a solution method, but it is preferably produced by a melting method in consideration of cost, working environment, and the like.

  The polyurethane resin can be produced by either the prepolymer method or the one-shot method.

  In the case of the prepolymer method, an isocyanate-terminated prepolymer having a molecular weight of about 800 to 5000 is preferable because it has excellent processability and physical characteristics.

  In the production of the polyurethane resin, a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound are mixed and cured. In the prepolymer method, the isocyanate-terminated prepolymer becomes an isocyanate group-containing compound, and the chain extender becomes an active hydrogen group-containing compound. In the one-shot method, the isocyanate component becomes an isocyanate group-containing compound, and the high molecular weight polyol, the low molecular weight component, and the like become active hydrogen group-containing compounds.

  The polyurethane foam, which is a material for forming the polishing layer of the present invention, can be produced by a mechanical foaming method (including a mechanical floss method) using a silicon surfactant.

  In particular, a mechanical foaming method using a silicon surfactant which is a polyalkylsiloxane or a copolymer of an alkylsiloxane and a polyetheralkylsiloxane is preferable. Examples of suitable silicon surfactants include SH-192 and L-5340 (manufactured by Toray Dow Corning Silicone), B-8443 (manufactured by Goldschmidt), and the like.

  The silicon-based surfactant is preferably added to the polyurethane foam in an amount of 0.1 to 15% by weight, more preferably 2 to 10% by weight.

  An example of a method for producing a polyurethane foam constituting the polishing layer will be described below. The manufacturing method of this polyurethane foam has the following processes.

  (1) The first component obtained by adding a silicon surfactant to an isocyanate-terminated prepolymer obtained by reacting an isocyanate component and a high molecular weight polyol is mechanically stirred in the presence of a non-reactive gas, and the non-reactive gas is removed. Disperse as fine bubbles to obtain a cell dispersion. Then, a second component containing a chain extender is added to the cell dispersion and mixed to prepare a cell-dispersed urethane composition. A catalyst may be appropriately added to the second component.

  (2) A silicon-based surfactant was added to at least one of the first component containing the isocyanate component (or isocyanate-terminated prepolymer) and the second component containing the active hydrogen group-containing compound, and the silicon-based surfactant was added. The components are mechanically stirred in the presence of a non-reactive gas, and the non-reactive gas is dispersed as fine bubbles to obtain a bubble dispersion. Then, the remaining components are added to the cell dispersion and mixed to prepare a cell-dispersed urethane composition.

  (3) A silicon-based surfactant is added to at least one of the first component containing the isocyanate component (or isocyanate-terminated prepolymer) and the second component containing the active hydrogen group-containing compound, and the first component and the second component are added. Is mechanically stirred in the presence of a non-reactive gas, and the non-reactive gas is dispersed as fine bubbles to prepare a cell-dispersed urethane composition.

  The cell dispersed urethane composition may be prepared by a mechanical floss method. The mechanical floss method is a method in which raw material components are put into a mixing chamber of a mixing head and a non-reactive gas is mixed and mixed and stirred by a mixer such as an Oaks mixer to make the non-reactive gas into a fine bubble state in the raw material mixture. It is a method of dispersing in. The mechanical floss method is a preferable method because the density of the polyurethane foam can be easily adjusted by adjusting the amount of the non-reactive gas mixed therein. Moreover, since the polyurethane foam which has a substantially spherical fine cell can be continuously shape | molded, manufacturing efficiency is good.

  As the non-reactive gas used to form the fine bubbles, non-flammable gases are preferable, and specific examples include nitrogen, oxygen, carbon dioxide, rare gases such as helium and argon, and mixed gases thereof. In view of cost, it is most preferable to use air that has been dried to remove moisture.

  As the stirring device for dispersing the non-reactive gas in the form of fine bubbles, a known stirring device can be used without any particular limitation. Specifically, a homogenizer, a dissolver, a two-axis planetary mixer (planetary mixer), a mechanical A floss foaming machine etc. are illustrated. The shape of the stirring blade of the stirring device is not particularly limited, but it is preferable to use a whipper type stirring blade because fine bubbles can be obtained. In order to obtain the target polyurethane foam, the rotational speed of the stirring blade is preferably 500 to 2000 rpm, more preferably 800 to 1500 rpm. The stirring time is appropriately adjusted according to the target density.

  In addition, it is also a preferable aspect that the stirring for preparing the cell dispersion in the foaming step and the stirring for mixing the first component and the second component use different stirring devices. The agitation in the mixing step may not be agitation that forms bubbles, and it is preferable to use an agitation device that does not involve large bubbles. As such an agitator, a planetary mixer is suitable. There is no problem even if the same stirring device is used as the stirring device for the foaming step for preparing the bubble dispersion and the mixing step for mixing each component, and the stirring conditions such as adjusting the rotation speed of the stirring blades are adjusted as necessary. It is also suitable to use after adjustment.

  Thereafter, the cell-dispersed urethane composition prepared by the above method is applied onto the base material layer, and the cell-dispersed urethane composition is cured to form a polyurethane foam (polishing layer) directly on the base material layer.

  A base material layer having a higher tensile strength than the polishing layer is used. Examples of such a base material layer include non-foamed plastic films such as polypropylene, polyethylene, polyester, polyamide, and polyvinyl chloride, polymer resin foams such as polyurethane foam, polyethylene foam, and polyester foam, butadiene rubber, and isoprene. Examples thereof include rubber resins such as rubber and photosensitive resins. Of these, non-foamed plastic films such as polypropylene, polyethylene, polyester, polyamide, and polyvinyl chloride, and polymer resin foams such as polyurethane foam, polyethylene foam, and polyester foam are preferably used.

  The tensile strength of the base material layer is preferably 50 to 500 MPa, and more preferably 150 to 300 MPa.

  The thickness of the base material layer is preferably 0.05 to 0.25 mm, more preferably 0.075 to 0.2 mm.

  The base material layer needs to have a product of tensile strength and thickness of 10 to 40 MPa · mm, and preferably 15 to 35 MPa · mm.

  As a method for applying the cell-dispersed urethane composition onto the base material layer, for example, a roll coater such as gravure, kiss, or comma, a die coater such as slot or phanten, a squeeze coater, or a curtain coater is adopted. Any method may be used as long as a uniform coating film can be formed on the base material layer.

  Heating and post-curing the polyurethane foam that has reacted until the cell-dispersed urethane composition is applied to the base material layer and no longer flows is effective in improving the physical properties of the polyurethane foam and is extremely suitable. is there. Post-cure is preferably performed at 30 to 80 ° C. for 10 minutes to 6 hours, and it is preferable to perform at normal pressure because the bubble shape becomes stable.

  In the production of a polyurethane foam, a known catalyst for promoting a polyurethane reaction such as a tertiary amine may be used. The type and addition amount of the catalyst are selected in consideration of the flow time for coating on the substrate layer after the mixing step of each component.

  The polyurethane foam may be produced by a batch method in which each component is weighed and put into a container and mechanically stirred, and each component and a non-reactive gas are continuously supplied to a stirring device and mechanically stirred. Further, a continuous production method in which a cell-dispersed urethane composition is sent out to produce a molded product may be used.

  Moreover, after forming a polyurethane foam on a base material layer, or forming a polyurethane foam simultaneously, it is preferable to adjust the thickness of a polyurethane foam uniformly. The method for uniformly adjusting the thickness of the polyurethane foam is not particularly limited, and examples thereof include a method of buffing with an abrasive, a method of pressing with a press plate, and a method of slicing with a slicer. When pressing, it is preferable to make the thickness of the cell-dispersed urethane composition as close as possible to the thickness of the intended polishing layer. Specifically, the thickness of the cell-dispersed urethane composition is adjusted to 80 to 100% of the thickness of the intended polishing layer. By keeping the thickness of the cell-dispersed urethane composition as thin as possible, internal heat generation during curing can be suppressed, and thereby variation in cell diameter can be suppressed.

  Moreover, the cell-dispersed urethane composition prepared by the above method is applied on the base material layer, and a release sheet is laminated on the cell-dispersed urethane composition. Thereafter, the polyurethane foam may be formed by curing the cell-dispersed urethane composition while making the thickness uniform by a pressing means.

  On the other hand, the cell-dispersed urethane composition prepared by the above method is applied onto a release sheet, and a base material layer is laminated on the cell-dispersed urethane composition. Thereafter, the polyurethane foam may be formed by curing the cell-dispersed urethane composition while making the thickness uniform by a pressing means.

  The material for forming the release sheet is not particularly limited, and examples thereof include general resin and paper. The release sheet preferably has a small dimensional change due to heat. The surface of the release sheet may be subjected to a release treatment.

  The pressing means for making the thickness of the sandwich sheet composed of the base material layer, the cell-dispersed urethane composition (cell-dispersed urethane layer), and the release sheet is not particularly limited. For example, the thickness may be constant by a coater roll, a nip roll, or the like. The method of compressing is mentioned. In consideration of the fact that the bubbles in the foam increase by about 1.1 to 1.5 times after compression, (compressor or nip clearance) − (thickness of substrate layer and release sheet) = ( The thickness of the polyurethane foam after curing is preferably 80 to 90%.

  Then, after the thickness of the sandwich sheet is made uniform, the reacted polyurethane foam is heated until it does not flow and post-cured to form a polishing layer. Post cure conditions are the same as described above.

  Thereafter, the release sheet on the upper surface side or lower surface side of the polyurethane foam is peeled off to obtain a laminate composed of the polyurethane foam (polishing layer) and the base material layer. In this case, since the skin layer is formed on the polyurethane foam, the skin layer is removed by buffing or the like. Further, when the polyurethane foam is formed by the mechanical foaming method as described above, the variation in bubbles is smaller on the lower surface side than on the upper surface side of the polyurethane foam. Therefore, when the release sheet on the lower surface side is peeled off and the lower surface side of the polyurethane foam is used as the polishing surface, the polishing surface has a small variation in bubbles, and the stability of the polishing rate is further improved.

  The shape of the laminate is not particularly limited, and may be a long shape with a width of about 50 to 200 cm and a length of about 10 to 50 m, or a rectangular shape with a width of about 50 to 200 cm and a length of about 0.5 to 3 m. Good.

  The average cell diameter of the polyurethane foam is preferably 40 to 100 μm, more preferably 60 to 80 μm.

  The average pore diameter of the open cells is preferably 5 to 30 μm, more preferably 20 to 30 μm.

  The specific gravity of the polyurethane foam is preferably 0.2 to 0.6, more preferably 0.3 to 0.5. When the specific gravity is less than 0.2, the durability of the polishing layer tends to decrease. On the other hand, if it is larger than 0.6, the material needs to have a low crosslinking density in order to obtain a certain elastic modulus. In that case, the permanent set increases and the durability tends to deteriorate.

  The hardness of the polyurethane foam is preferably 10 to 95 degrees, more preferably 40 to 90 degrees, as measured by an Asker C hardness meter. When the Asker C hardness is less than 10 degrees, the durability of the polishing layer tends to decrease, or the surface smoothness of the polished material after polishing tends to deteriorate. On the other hand, when it exceeds 95 degrees, scratches are likely to occur on the surface of the material to be polished.

  The surface of the polishing layer may have a concavo-convex structure for holding and renewing the slurry. The polishing layer made of foam has many openings on the polishing surface and has the function of holding and updating the slurry. By forming a concavo-convex structure on the polishing surface, the slurry can be held and updated more efficiently. It can be performed well, and destruction of the polishing object due to adsorption with the polishing object can be prevented. The concavo-convex structure is not particularly limited as long as it is a shape that holds and renews the slurry. For example, an XY lattice groove, a concentric circular groove, a through hole, a non-penetrating hole, a polygonal column, a cylinder, a spiral groove, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. In addition, these uneven structures are generally regular, but in order to make the slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible.

  The method for producing the concavo-convex structure is not particularly limited. For example, a method of machine cutting using a jig such as a tool of a predetermined size, pouring a resin into a mold having a predetermined surface shape, and curing. Using a press plate having a predetermined surface shape, a method of producing a resin by pressing, a method of producing using photolithography, a method of producing using a printing technique, a carbon dioxide laser, etc. Examples include a manufacturing method using laser light.

  The tensile strength of the polishing layer is preferably 1 to 20 MPa, more preferably 2.5 to 10 MPa.

  The thickness of the polishing layer is preferably 0.2 to 2.5 mm, more preferably 0.5 to 2.0 mm.

  The polishing layer needs to have a product of tensile strength and thickness at the cut line position of 2 to 10 MPa · mm, and preferably 3 to 7 MPa · mm. It should be noted that a cut line may be provided not only in the base material layer but also in the polishing layer at the cut line position.

  Hereinafter, the manufacturing method of the lamination sheet for polishing pad preparation of this invention is demonstrated, referring FIGS.

  1 and 2 are schematic cross-sectional views in the length direction of a laminate 3 composed of a polishing layer 1 and a base material layer 2. In the present invention, as shown in FIG. 1, the cut line 4 needs to penetrate at least the base material layer 1. Further, as shown in FIG. 2, the cut line 4 may be formed up to the inside of the polishing layer 1.

  The cut line 4 is provided for cutting a long or rectangular laminated sheet for manufacturing a polishing pad into an appropriate size or cutting into a polishing pad shape. The tear line 4 in the base material layer may be provided continuously or intermittently (discontinuously). The cut line 4 in the polishing layer 1 is provided continuously or intermittently. However, when the cut line 4 penetrates the polishing layer 1, it is necessary to provide the cut line 4 intermittently so that the polishing layer is not completely separated.

  The cut line 4 needs to be formed so that the tearing force of the laminate 3 at the cut line position is 1 to 4N, and preferably 1.5 to 4N. The tearing force of the laminate 3 at the cut line position can be adjusted by the material of the polishing layer, the depth of the cut line 4 in the polishing layer, the length of the cut line 4 in the polishing layer, and the like.

  Examples of the method for forming the cut line 4 include a method of cutting with a ceramic blade, a processing method using a water cutter or a laser, and a pressing method using a Thomson blade.

  FIG. 3 is a schematic view showing the surface state of the back surface side of the base material layer 2. When a circular polishing pad is cut from the laminated sheet for producing a polishing pad, it is preferable to provide an auxiliary cut line 4b connected to the circular cut line 4a. If the circular cut line 4a is connected to the end portion of the base material layer 2, the end portion of the polishing pad may be damaged. By providing the circular cut line 4a inside the base material layer 2 and providing the auxiliary cut line 4b connected to the circular cut line 4a, the polishing pad can be prevented from being damaged, and the polishing pad can be easily cut.

  The laminated sheet for producing a polishing pad of the present invention can be produced by bonding an adhesive sheet 7 comprising an adhesive layer 5 and a release sheet 6 to the laminate 3. FIG. 4 is a schematic cross-sectional view in the length direction of the laminated sheet 8 for producing a polishing pad.

  The material for forming the pressure-sensitive adhesive layer 5 is not particularly limited, and examples thereof include acrylic, rubber-based, and silicon-based pressure-sensitive adhesives. The pressure-sensitive adhesive layer 5 is provided for attaching the polishing pad to the polishing surface plate.

  The material for forming the release sheet 6 is not particularly limited, and examples thereof include general resin and paper. The release sheet 6 preferably has a small dimensional change due to heat. Further, the surface of the release sheet 6 may be subjected to a release treatment. Moreover, you may attach the mark for grasping | ascertaining the position of the cut line 4 provided in the base material layer 4 on the surface of the peeling sheet 6. FIG.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[Measurement and evaluation methods]
(Measurement of average pore diameter and average bubble diameter)
A sample obtained by cutting the produced polyurethane foam in parallel with a razor blade as thin as possible to a thickness of 1 mm or less was used as a sample. The sample was fixed on a glass slide and observed at 100 times using SEM (S-3500N, Hitachi Science Systems, Ltd.). Using the image analysis software (WinRoof, Mitani Shoji Co., Ltd.), measure the pore diameter (diameter) and bubble diameter (diameter) of all open cells in an arbitrary range, and calculate the average pore diameter and average bubble diameter. did. However, in the case of an elliptical hole or bubble, the area was converted to a circle area, and the equivalent circle diameter was defined as the hole diameter or bubble diameter.

(Measurement of specific gravity)
This was performed according to JIS Z8807-1976. The produced polyurethane foam was cut into a 4 cm × 8.5 cm strip (thickness: arbitrary) as a sample and allowed to stand for 16 hours in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5%. The specific gravity was measured using a hydrometer (manufactured by Sartorius).

(Measurement of hardness)
This was performed according to JIS K-7312. The produced polyurethane foam was cut into a size of 5 cm × 5 cm (thickness: arbitrary) as a sample and allowed to stand for 16 hours in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5%. At the time of measurement, the samples were overlapped to have a thickness of 10 mm or more. Using a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., Asker C type hardness meter, pressure surface height: 3 mm), the hardness 60 seconds after contacting the pressure surface was measured.

(Measurement of tearing force of the laminate at the cut line position)
It measured based on the trouser tear method of JIS K-7128-1. The produced laminate was cut into a size of 15 cm long × 5 cm wide. However, the cut line is cut out so as to be formed in the center in the width direction and 7.5 cm from one end in the length direction. And the slit was put into the center of the cut-out laminated body in the width direction from the other end of the length direction to 7.5 cm, and the sample was produced. The sample was allowed to stand for 24 hours in an environment of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%. In the measurement, the tearing speed was 200 mm / min, 20 mm after the start of tearing and 5 mm before the end of tearing were excluded, and the average value of the tearing force of the remaining 50 mm was taken as the tearing force (N).

(Measurement of tensile strength of polishing layer at cut line position)
The measurement was performed in accordance with the tensile property test method of JIS K-7312-1996. The prepared polishing layer was punched into the shape of dumbbell No. 1 to obtain a sample. However, when a cut line is provided in the polishing layer, the polishing layer is punched out so that the cut line is formed at the center of the dumbbell 1 and perpendicular to the tensile direction. The sample was allowed to stand for 24 hours in an environment of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%. The measurement was performed using an Instron universal testing machine (Instron, Model 4300), measuring the breaking strength (MPa) at a test speed of 50 mm / min, and setting it as the tensile strength.

(Measurement of tensile strength of base material layer)
It measured based on the test method of the tensile property of JIS K-7127-1999. The used base material layer was punched into the shape of test piece type 5 to obtain a sample. The sample was allowed to stand for 24 hours in an environment of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%. The measurement was performed using an Instron universal testing machine (Instron, Model 4300), measuring the breaking strength (MPa) at a test speed of 50 mm / min, and setting it as the tensile strength.

(Appearance evaluation)
When a laminated sheet is produced by laminating an adhesive sheet on the surface of the base material layer, when a wrinkle, a crack from a tear line, or a deviation of the lamination occurs, or the produced laminated sheet is used as a scroll, and this temperature is 23. X is when the surface of the polishing layer is left to stand for 24 hours in an environment of ℃ ± 2 ℃ and humidity is 50% ± 5%. The case where these did not occur was marked as ◯.

(Evaluation of cut part)
When the tear shape of the sample after measuring the tear force was torn almost linearly on the slit extension line, the tear shape was meandering, or peeling was observed between the polishing layer and the base material layer. The case was marked with x.

Example 1
In a container, polytetramethylene ether glycol having a number average molecular weight of 650 (manufactured by Mitsubishi Chemical Corporation, PTMG650, hydroxyl value: 173 mg KOH / g, functional group number: 2) 38 parts by weight, polycaprolactone diol (manufactured by Daicel Chemical Industries, Plaxel 205, Hydroxyl value: 208 mg KOH / g, functional group number: 2) 25 parts by weight, polycaprolactone triol (manufactured by Daicel Chemical Industries, Plaxel 305, hydroxyl value: 305 mg KOH / g, functional group number: 3), 35 parts by weight, trimethylolpropane (hydroxyl group) Value: 2 parts by weight of 1128 mg KOH / g), 10 parts by weight of a silicon surfactant (manufactured by Goldschmidt, B8443), and 0.1 part by weight of a catalyst (manufactured by Kao Corporation, KAOLIZER No. 25) are mixed and mixed. A second component (25 ° C.) was prepared. And it stirred vigorously for about 4 minutes so that a bubble might be taken in in a reaction system with the rotation speed of 900 rpm using the stirring blade. Thereafter, 72.21 parts by weight of carbodiimide-modified MDI (manufactured by Nippon Polyurethane Industry, Millionate MTL, NCO wt%: 29 wt%, 25 ° C.) as the first component was added to the second component (NCO / OH = 1.1). ) And stirring for about 1 minute to prepare a cell-dispersed urethane composition.

  The prepared cell-dispersed urethane composition was applied onto a release-treated release sheet (manufactured by Toyobo Co., Ltd., polyethylene terephthalate, width: 100 cm, length: 2500 cm, thickness: 0.1 mm). Formed. A base material layer B (polyethylene terephthalate, width: 100 cm, length: 2500 cm, thickness: 0.188 mm) was placed on the cell-dispersed urethane layer. The cell-dispersed urethane layer was 2.7 mm thick with a nip roll, and then cured at 70 ° C. for 3 hours to form a polyurethane foam (open cell structure, average cell diameter: 68.5 μm, average pore size: 24 μm, specific gravity: 0.00). 47, C hardness: 50 degrees). Thereafter, the release sheet under the polyurethane foam was peeled off. Next, the surface of the polyurethane foam was buffed using a buffing machine (Amitech) to form a polishing layer A having a thickness of 1 mm to produce a laminate. The polyurethane foam had substantially spherical open cells. Then, only the base material layer B was cut | disconnected in the width direction using the ceramic blade as shown in FIG. 1, and the cut line was provided in the laminated body. Then, using a laminator (roll interval is 0.1 mm narrower than the total thickness of the laminate and the pressure-sensitive adhesive sheet) on the surface of the base material layer B, the pressure-sensitive adhesive sheet (manufactured by Sekisui Chemical Co., Ltd., double tack tape) has a speed of 1 m. A laminated sheet for producing a polishing pad was produced by laminating at / min.

Example 2
Lamination for making polishing pad in the same manner as in Example 1 except that base material layer C (polyethylene terephthalate, width: 100 cm, length: 2500 cm, thickness: 0.1 mm) was used instead of base material layer B A sheet was produced.

Example 3
Implemented except using base material layer E (manufactured by Toyobo Co., Ltd., foamed polyethylene terephthalate, specific gravity: 1.1, width: 100 cm, length: 2500 cm, thickness: 0.1 mm) instead of base material layer B A laminated sheet for producing a polishing pad was produced in the same manner as in Example 1.

Example 4
As shown in FIG. 2, the polishing layer B was prepared by cutting in the width direction from the surface of the base material layer B to the thickness of the polishing layer A of 0.5 mm, and the cut line was provided in the laminate. A laminated sheet for producing a polishing pad was produced in the same manner.

Example 5
Only the base material layer B is cut in the width direction to provide a cut line X, and further along the cut line X, a cut line Y (length: 2.5 mm, interval: 2.5 mm) penetrating the polishing layer A is provided. A polishing sheet D was produced, and a laminated sheet for producing a polishing pad was produced in the same manner as in Example 1 except that a cut line was provided on the laminate.

Example 6
A laminated sheet for preparing a polishing pad was prepared in the same manner as in Example 1 except that the surface of the polyurethane foam was buffed to form a polishing layer E having a thickness of 1.5 mm.

Comparative Example 1
Implemented except that instead of the base material layer B, the base material layer A (manufactured by Toyobo Co., Ltd., foamed polyethylene terephthalate, specific gravity: 1.1, width: 100 cm, length: 2500 cm, thickness: 0.25 mm) was used. A laminated sheet for producing a polishing pad was produced in the same manner as in Example 1.

Comparative Example 2
In the same manner as in Example 1 except that instead of the base material layer B, a base material layer D (manufactured by Toyobo Co., Ltd., polyethylene terephthalate, width: 100 cm, length: 2500 cm, thickness: 0.025 mm) was used. A laminated sheet for producing a polishing pad was produced.

Comparative Example 3
Implemented except that the base material layer F (made by Toray Industries Inc., Toray Pef, width: 100 cm, length: 2500 cm, specific gravity: 0.18, thickness: 1 mm) was used instead of the base material layer B A laminated sheet for producing a polishing pad was produced in the same manner as in Example 1.

Comparative Example 4
As shown in FIG. 2, the polishing layer C was prepared by cutting in the width direction from the surface of the base material layer B to the thickness of the polishing layer A of 0.8 mm, and a cut line was provided in the laminate. A laminated sheet for producing a polishing pad was produced in the same manner.

Comparative Example 5
A laminated sheet for producing a polishing pad was produced in the same manner as in Example 1 except that the surface of the polyurethane foam was buffed to form a polishing layer F having a thickness of 2.5 mm.

Comparative Example 6
A laminated sheet for producing a polishing pad was produced in the same manner as in Example 1 except that the cut line was not provided on the laminated body.

Comparative Example 7
For the production of a polishing pad in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was bonded to the laminate, and then cut from the pressure-sensitive adhesive sheet surface to the thickness 0.5 mm of the polishing layer A in the width direction to provide a tear line A laminated sheet was produced.

Schematic cross-sectional view in the length direction of the laminate Schematic cross-sectional view in the length direction of the laminate Schematic showing the surface state of the back side of the base material layer Schematic cross-sectional view in length direction of laminated sheet for polishing pad preparation

Explanation of symbols

1: Polishing layer 2: Base material layer 3: Laminate 4: Cut line 4a: Circular cut line 4b: Auxiliary cut line 5: Adhesive layer 6: Release sheet 7: Adhesive sheet 8: Laminated sheet for polishing pad preparation

Claims (3)

In the laminated sheet for producing a polishing pad, a polishing layer is provided on one side of the base material layer, and an adhesive sheet composed of an adhesive layer and a release sheet is provided on the other side.
The polishing layer has a substantially spherical open cell, and consists of a thermosetting polyurethane foam containing no abrasive grains,
The polishing layer is self-adhering to the base material layer,
The laminated sheet is provided with a tear line penetrating at least the base material layer,
The tearing force of the laminate composed of the polishing layer and the base material layer at the cut line position is 1 to 4 N,
The polishing layer has a product of tensile strength and thickness at the cut line position of 2 to 10 MPa · mm,
The base material layer has a tensile strength larger than that of the polishing layer, and the product of the tensile strength and the thickness is 10 to 40 MPa · mm,
The adhesive sheet is not provided with a cut line,
A laminated sheet for producing a polishing pad characterized by the above. The laminated sheet for producing a polishing pad according to claim 1, wherein the cut line is provided up to the inside of the polishing layer. The laminated sheet for producing a polishing pad according to claim 1, wherein the cut line is provided continuously or intermittently.

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