JP6248606B2 - Urethane resin composition and perforated sheet using the same - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention can be used as a material for a polishing pad and the like, a urethane resin composition capable of obtaining a foamed state suitable for a polishing pad and the like and a porous sheet in which carbon black aggregation is suppressed, and a porous body using the same Regarding the sheet.

  A porous sheet obtained by wet-forming a urethane resin composition containing a urethane resin as a main component and using N, N-dimethylformamide (hereinafter abbreviated as “DMF”) as a solvent includes a hard disk substrate and a silicon wafer. It is used as a polishing pad used in a manufacturing process of a semiconductor device or the like, or a support pad used in a manufacturing process of a glass substrate, a photomask or the like used in a liquid crystal display device.

  In addition to chemical resistance to the polishing liquid, durability against compression and friction, the above polishing pads, etc. are required to have a homogeneous material. To achieve this, carbon black is blended into the urethane resin composition. (For example, refer to Patent Document 1). This carbon black is used for the purpose of improving strength and adjusting viscoelasticity in addition to coloring.

  In addition, attempts have been made to adjust the foamed state of the urethane resin composition by blending various surfactants into a polishing pad, in particular, to enlarge the void due to foaming (see, for example, Patent Document 2).

  However, in order to adjust the foaming state while maintaining chemical resistance to the polishing liquid, durability against compression and friction, etc., when carbon black and a surfactant are added to the urethane resin composition, Aggregates of carbon black are generated and remain after the polishing pad is formed, which causes a problem of scratching the material to be polished.

  Accordingly, there has been a demand for a urethane resin composition that suppresses agglomeration of carbon black that causes scratches on the material to be polished and that provides a foamed polishing pad suitable for the polishing pad.

Japanese Patent Publication No. 5-20268 Japanese Patent Publication No. 60-28304

  The problem to be solved by the present invention is a urethane resin composition that can be used as a material for a polishing pad or the like, can obtain a foamed state suitable for a polishing pad or the like, and can obtain a porous sheet with suppressed carbon black aggregation And a porous sheet using the same.

  As a result of earnest research to solve the above problems, the present inventors have used an anionic surfactant having a neutralized salt of an acid group having an acid dissociation constant in a specific range in the urethane resin composition. The inventors have found that a foamed state suitable for a porous sheet can be obtained and that aggregation of carbon black can be suppressed, and the present invention has been completed.

  That is, the present invention includes urethane resin (A), carbon black (B), anionic surfactant (C) having a neutralized salt of an acid group having an acid dissociation constant (pKa) in the range of 0 to 6, and The present invention relates to a urethane resin composition containing N, N-dimethylformamide (D) and a porous sheet using the same.

  The urethane resin composition of the present invention can be used as a material for a porous sheet such as a polishing pad, a foamed state suitable for a polishing pad or the like can be obtained, and aggregation of carbon black can be suppressed. Therefore, the porous sheet obtained by using the urethane resin composition of the present invention is a hard disk substrate, a silicon wafer, a semiconductor device, a glass substrate used for a liquid crystal display, a polishing pad used for surface polishing of a photomask, or a liquid crystal It can be suitably used as a support pad used in a polishing process of a glass substrate, a photomask or the like used in a display device.

FIG. 1 is a photograph in which the inner surface of the foamed portion near the surface of the porous sheet (1) obtained in Example 1 is magnified 10,000 times with a scanning electron microscope. FIG. 2 is a photograph in which the inner surface of the foamed portion near the surface of the porous sheet (R1) obtained in Comparative Example 1 is magnified 10,000 times with a scanning electron microscope. FIG. 3 is a photograph of the cross section of the porous sheet (1) obtained in Example 1 magnified 100 times with a scanning electron microscope. FIG. 4 is a photograph of the cross section of the porous sheet (R4) obtained in Comparative Example 4 magnified 100 times with a scanning electron microscope.

  The urethane resin composition of the present invention comprises an anionic surfactant (C) having a urethane resin (A), carbon black (B), and an acid group neutralization salt having an acid dissociation constant (pKa) in the range of 0 to 6. ), And N, N-dimethylformamide (D).

  Examples of the urethane resin (A) include those obtained by reacting a high molecular weight polyol (a1), a low molecular weight polyol (a2), and a polyisocyanate (a3). Specific examples include polyester urethane resins, polyether urethane resins, polyester ether urethane resins, and polycarbonate urethane resins. These urethane resins can be used alone or in combination of two or more.

  Examples of the high molecular weight polyol (a1) include polyester polyol, polyether polyol, polycarbonate polyol, and mixtures and copolymers thereof.

  The polyester polyol is obtained by esterifying a polyol and a polycarboxylic acid. Examples of the polyol used as a raw material for the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl. -1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedi Examples include methanol, hydrogenated bisphenol A and its alkylene oxide adduct, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol and the like. These polyols can be used alone or in combination of two or more.

  Examples of the polycarboxylic acid used as a raw material for the polyester polyol include succinic acid, adipic acid, azelaic acid, sebacic acid, todecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1, Examples include 4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and anhydrides or ester-forming derivatives of these polycarboxylic acids. These polycarboxylic acids can be used alone or in combination of two or more.

  Moreover, as the polyester polyol, a polyester obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone can also be used. These polyester polyols can be used alone or in combination of two or more.

  Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator. Examples of the compound having two or more active hydrogen atoms include propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, diester, and the like. Examples include glycerin, trimethylolethane, trimethylolpropane, water, hexanetriol and the like. Examples of the alkylene oxide include propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran. These polyether polyols can be used alone or in combination of two or more.

  The polycarbonate polyol is obtained by esterifying carbonic acid or a carbonic acid ester with a polyhydric alcohol. Examples of the polyhydric alcohol include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These polycarbonate polyols can be used alone or in combination of two or more.

  Further, the high molecular weight polyol (a1) preferably has a number average molecular weight in the range of 500 to 5,000, more preferably a number average molecular weight in the range of 1,000 to 3,500.

  Examples of the low molecular weight polyol (a2) include a polyol having a molecular weight of about 40 to 200. Specific examples of the low molecular weight polyol (a2) include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, and 3-methyl-1. , 5-pentanediol, 1,6-hexanediol, 3,3′-dimethylol heptane, 1,4-cyclohexanedimethanol, neopentyl glycol, 3,3-bis (hydroxymethyl) heptane, diethylene glycol, dipropylene Polyhydric alcohols such as glycol, glycerin, trimethylolpropane, sorbitol, hydroquinone diethylol ether; amine compounds, amino acids, alkanolamines, silicone-modified compounds, and the like. These low molecular weight polyols can be used alone or in combination of two or more.

  Examples of the polyisocyanate (a3) include 1,3- and 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, and 1-methyl-2. , 5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4 -Diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'- Diisocyanate, biphenyl-2,4′-diisocyanate, biphenyl-4,4′-diisocyanate, 3-3′-dimethylbiphenyl-4,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,2 ′ -Diisocyanate, di Phenylmethane-2,4-diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4- Cyclohexylene diisocyanate, 1,3-di (isocyanatemethyl) cyclohexane, 1,4-di (isocyanatemethyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 2,4′-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane Diisocyanate etc. are mentioned. Also, trimers of these diisocyanates can be used. These polyisocyanates can be used alone or in combination of two or more.

  Among the above polyisocyanates (a3), diphenylmethane-4,4'-diisocyanate is preferable because a porous sheet having a good foamed shape can be obtained by wet film formation.

  The urethane resin (A) is prepared by, for example, mixing and reacting the high molecular weight polyol (a1), the low molecular weight polyol (a2) and the polyisocyanate (a3) in the absence of a solvent or in the presence of an organic solvent. Can be manufactured.

  Examples of the organic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone, methyl n-propyl ketone, acetone, methyl isobutyl ketone, methyl formate, and ethyl formate. Propyl formate, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, t-butyl acetate and the like.

  The ratio of the high molecular weight polyol (a1) and the low molecular weight polyol (a2) used in the production of the urethane resin (A) is 1 / 0.0 in molar ratio [(a1) / (a2)]. A range of 5 to 1/20 is preferable, and a range of 1/1 to 1/10 is more preferable. The polyisocyanate (a3) is an equivalent ratio [isocyanate group / hydroxyl group] of the hydroxyl group of the high molecular weight polyol (a1) and the low molecular weight polyol (a2) and the isocyanate group of the polyisocyanate (a3). In the range of 0.8 to 1.2, the range of 0.9 to 1.1 is more preferable.

  As the carbon black (B), various commercially available products can be used for paint, printing ink, plastic coloring, toner, and the like. Carbon black is classified into channel black, roller black, gas furnace black, oil furnace black, thermal black, acetylene black, and the like depending on the production method, and any of them can be used.

  The carbon black (B) is preferably dispersed using a three-roll mill, a ball mill, a bead mill or the like, so that the carbon black (B) is uniformly dispersed in the urethane resin composition. For example, the urethane resin composition of the present invention can be prepared by dispersing all components of the urethane resin composition. Further, a part or all of the urethane resin (A), all of the carbon black (B), and part or all of the N, N-dimethylformamide (D) are dispersed to prepare a carbon black dispersion in advance. Can be mixed with the remainder of the urethane resin (A), the anionic surfactant (C), and the remainder of the N, N-dimethylformamide (D) to obtain the urethane resin composition of the present invention.

  In preparing the urethane resin composition or the carbon black dispersion, a dispersant that is an anionic compound, a cationic compound, a nonionic compound, or a polymer compound may be used.

  The anionic surfactant (C) has an acid group neutralized salt having an acid dissociation constant (pKa) in the range of 0 to 6. Here, the acid dissociation constant (pKa) represents the first-stage pKa for those dissociating in multiple stages. In addition, the acid dissociation constant (pKa) is determined by using an automatic potentiometric titrator (for example, Kyoto Electronics Industry Co., Ltd.) for a compound having an acid group such as a carboxyl group before neutralization with a base to make an anionic surfactant (C). It is a value measured using “AT-510” manufactured by company.

  In the present invention, the acid dissociation constant (pKa) is in the range of 0 to 6, but when the pKa is less than 0 (negative value), a porous sheet that suppresses aggregation of the carbon black (B) is obtained. If the pKa exceeds 6, there is a problem that a suitable foamed state cannot be obtained for the porous sheet. Moreover, since the suppression of aggregation of the carbon black (B) and a suitable foaming state can be realized at a higher level, the acid dissociation constant (pKa) is preferably in the range of 1 to 5, A range is more preferred.

  The acid dissociation constant (pKa) is in the range of 0 to 6, the base used when the acid group is used as a neutralized salt, the alkali metal anionic surfactant (C) is, for example, an amino acid surfactant Is mentioned. Examples of the amino acid surfactant include alkali metal salts, amine salts, and ammonium salts of N-fatty acid acylamino acids obtained by reacting amino acids with fatty acids. The anionic surfactant (C) can be used alone or in combination of two or more.

  Examples of the fatty acid used as a raw material for the N-fatty acid acylamino acid include coconut oil fatty acid, beef tallow fatty acid, palm oil fatty acid, palm kernel oil fatty acid, lauric acid, myristic acid, palmitic acid, stearic acid and the like.

  Examples of the amino acid that is a raw material for the N-fatty acid acylamino acid include glycine, alanine, β-alanine, sarcosine, valine, leucine, isoleucine, aspartic acid, and glutamic acid. Regarding optical isomers, any of D-form, L-form, and mixtures thereof can be used.

  Examples of the alkali metal used when the N-fatty acid acylamino acid is used as an alkali metal salt include sodium, potassium, lithium and the like. Examples of amine compounds used when N-fatty acid acylamino acids are used as amine salts include triethanolamine, triethylamine, diethanolamine, methyldiethanolamine, dibutylamine, and monoethanolamine. Furthermore, ammonia water is used when the N-fatty acid acylamino acid is converted to an ammonium salt.

  Specific examples of the amino acid surfactant (C) include N-coconut oil fatty acid acyl glutamic acid triethanolamine, N-coconut oil fatty acid acylglycine triethanolamine, N-coconut oil fatty acid acylalanine triethanolamine, N- Palm oil fatty acid acyl sarcosine triethanolamine, N-coconut oil fatty acid sodium acylglutamate, N-coconut oil fatty acid acylglycine sodium, N-coconut oil fatty acid acylalanine sodium, N-coconut oil fatty acid acyl sarcosine sodium, N-coconut oil fatty acid Amino acid surfactants derived from coconut oil fatty acids such as potassium acylglutamate, N-coconut oil fatty acid acylglycine potassium, N-coconut oil fatty acid acylalanine potassium, N-coconut oil fatty acid acyl sarcosine potassium; Triethanolamine tamate, N-tallow fatty acid acylglycine triethanolamine, N-tallow fatty acid acylalanine triethanolamine, N-tallow fatty acid acyl sarcosine triethanolamine, N-tallow fatty acid sodium acylglutamate, N-tallow fatty acid acylglycine Sodium, N-beef tallow fatty acid acylalanine sodium, N-beef tallow fatty acid acyl sarcosine sodium, N-tallow tallow fatty acid acyl potassium glutamate, N-tallow tallow fatty acid acyl glycine potassium, N-tallow tallow fatty acid acyl alanine potassium, N-tallow tallow fatty acid acyl sarcosine potassium, etc. Amino acid surfactants derived from beef tallow fatty acids; N-palm oil fatty acid acyl glutamic acid triethanolamine, N-palm oil fatty acid acylglycine triethanolamine, N-pa Mu-fatty acid acylalanine triethanolamine, N-palm oil fatty acid acyl sarcosine triethanolamine, N-palm oil fatty acid acyl sodium glutamate, N-palm oil fatty acid acyl glycine sodium, N-palm oil fatty acid acyl alanine sodium, N-palm Oil fatty acid acyl sarcosine sodium, N-palm oil fatty acid potassium acyl glutamate, N-palm oil fatty acid acyl glycine potassium, N-palm oil fatty acid acyl alanine potassium, N-palm oil fatty acid acyl sarcosine potassium, etc. Surfactant; N-palm kernel oil fatty acid acyl glutamate triethanolamine, N-palm kernel oil fatty acid acylglycine triethanolamine, N-palm kernel oil fatty acid acylalanine triethanol Amine, N-palm kernel oil fatty acid acyl sarcosine triethanolamine, N-palm kernel oil fatty acid sodium acyl glutamate, N-palm kernel oil fatty acid acyl glycine sodium, N-palm kernel oil fatty acid acyl alanine sodium, N-palm kernel oil fatty acid Derived from palm kernel oil fatty acid such as sodium acyl sarcosine, potassium N-palm kernel oil fatty acid acyl glutamate, N-palm kernel oil fatty acid acyl glycine potassium, N-palm kernel oil fatty acid acyl alanine potassium, N-palm kernel oil fatty acid acyl sarcosine potassium N-lauroyl acylglutamate triethanolamine, N-lauroyl acylglycine triethanolamine, N-lauroyl acylalanine triethanolamine, N-lauroyl acylsal Sintriethanolamine, sodium N-lauroyl acylglutamate, sodium N-lauroyl acylglycine, sodium N-lauroyl acylalanine, sodium N-lauroyl acyl sarcosine, potassium N-lauroyl acyl glutamate, potassium N-lauroyl acylglycine, N- Amino acid surfactants derived from lauric acid such as potassium lauroyl acylalanine and potassium N-lauroyl acyl sarcosine; N-myristoyl acyl glutamic acid triethanolamine, N-myristoyl acylglycine triethanolamine, N-myristoyl acylalanine triethanolamine, N-myristoyl acyl sarcosine triethanolamine, N-myristoyl acyl sodium glutamate, N-myris Myristic acid such as sodium ylacylglycine, sodium N-myristoyl acylalanine, sodium N-myristoyl acyl sarcosine, potassium N-myristoyl acyl glutamate, potassium N-myristoyl acyl glycine, potassium N-myristoyl acylalanine, potassium N-myristoyl acyl sarcosine Derived amino acid surfactants: N-palmitoyl acyl glutamate triethanolamine, N-palmitoyl acylglycine triethanolamine, N-palmitoyl acylalanine triethanolamine, N-palmitoyl acyl sarcosine triethanolamine, N-palmitoyl acyl glutamate sodium N-palmitoyl acylglycine sodium, N-palmitoyl acylalanine sodium N-palmitoyl acyl sarcosine sodium, N-palmitoyl acyl potassium glutamate, N-palmitoyl acyl glycine potassium, N-palmitoyl acyl alanine potassium, N-palmitoyl acyl sarcosine potassium, and other amino acid surfactants derived from palmitic acid; N-stearoyl Acylglutamate triethanolamine, N-stearoyl acylglycine triethanolamine, N-stearoyl acylalanine triethanolamine, N-stearoyl acyl sarcosine triethanolamine, N-stearoyl acyl sodium glutamate, N-stearoyl acyl glycine sodium, N-stearoyl Acylalanine sodium, N-stearoyl acyl sarcosine sodium, N-stearoyl acyl group Potassium glutamic acid, N- stearoyl-acyl glycine potassium, N- stearoyl-acyl alanine potassium, such as an amino acid-based surfactants derived from stearic acid, such as N- stearoyl-acyl sarcosine potassium and the like.

  Among the above-mentioned amino acid surfactants, triethanolamine salts are preferred because they can further suppress the aggregation of carbon black (B). N-coconut oil fatty acid acyl sarcosine triethanolamine, N-coconut oil fatty acid acylalanine Triethanolamine and N-lauroyl acylalanine triethanolamine are more preferable.

  The compounding amount of the carbon black (B) in the urethane resin composition of the present invention is such that durability against compression and friction can be made more suitable as a polishing pad. Therefore, with respect to 100 parts by mass of the urethane resin (A), The range of 1-20 mass parts is preferable, and the range of 3-15 mass parts is more preferable. Moreover, since the foaming state can be made more suitable as a polishing pad, the mixing ratio of the anionic surfactant (C) is in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the urethane resin (A). The range of 3 to 15 parts by mass is more preferable. Furthermore, the compounding amount of DMF (D) is preferably in a range where the solid content concentration of the urethane resin composition is 5 to 60% by mass.

  In the urethane resin composition of the present invention, in order to form a uniform and fine continuous foamed cell structure in order to adjust the film formation rate at the time of polishing pad preparation, good planar smoothness, and uniform film formation, a wet film formation aid is necessary. An agent may be blended. Examples of the wet film forming aid include castor oil, glycerin / tripalmitate, and silicone oil. These wet film-forming aids can be used alone or in combination of two or more.

  The porous sheet of the present invention can be produced by a known wet film forming method. After applying the urethane resin composition of the present invention to the substrate, the solvent and water in the urethane resin composition are replaced by immersing in water, and a solid matter in the urethane resin composition is deposited to form a film. . Then, the porous sheet using the urethane resin composition of the present invention can be produced by thoroughly washing away residual DMF with water, squeezing with mangle roll, and drying.

  Examples of the base material of the porous sheet of the present invention include films and nonwoven fabrics. Examples of the raw material for the nonwoven fabric include polyester, polyamide, and polyvinyl alcohol. In order to maintain the flatness of the porous sheet of the present invention, the substrate is preferably a film or a high-density nonwoven fabric.

  The porous sheet of the present invention obtained by the manufacturing method as described above is a surface polishing of a hard disk substrate, a silicon wafer, a semiconductor device, a glass substrate used for a liquid crystal display device, a photomask, etc., if necessary, by removing the surface layer. It can be suitably used as a support pad used in a polishing step of a polishing pad used in a polishing process, a glass substrate used in a liquid crystal display device, a photomask or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

(Production Example 1: Production of urethane resin (A-1))
155.4 parts by weight of polyester diol (number average molecular weight 2,000) obtained by reacting ethylene glycol and adipic acid in a reaction apparatus equipped with a stirrer, a condenser reflux and a thermometer, 24.9 ethylene glycol Of urethane resin (A-1) by charging 6 parts by weight, 700 parts by weight of N, N-dimethylformamide, and 119.7 parts by weight of 4,4′-diphenylmethane diisocyanate and reacting at 60 ° C. for 6 hours with stirring. A 30 mass% DMF solution was obtained. The viscosity at 25 ° C. of the 30% by mass DMF solution of the obtained urethane resin (A-1) was 55 Pa · s.

(Preparation Example 1: Preparation of carbon black dispersion)
In a stainless steel container with a lid, 10 parts by mass of carbon black ("MA-100" manufactured by Mitsubishi Chemical Corporation), 333.3 parts by mass of a 30% by mass DMF solution of the urethane resin (A-1) obtained in Production Example 1 (100 parts by mass as urethane resin (A-1)) and 156.7 parts by mass of DMF were added and mixed for 30 minutes with a dispersion stirrer. Subsequently, a carbon black dispersion was obtained by a dispersion treatment using a three-roll mill. The obtained carbon black dispersion had a particle size of 10 μm observed according to JIS K-5101 and K5600 using a grind gauge with a maximum depth of 25 μm.

Example 1
500 parts by mass of the carbon black dispersion obtained in Preparation Example 1, 33.3 parts by mass of N-coconut oil fatty acid sarcosine triethanolamine aqueous solution (non-volatile content 30% by mass) (10 parts by mass as N-coconut oil fatty acid sarcosine triethanolamine) Part), 70 parts by mass of DMF, and 3.3 parts by mass of a wet film-forming auxiliary (“Crisbon Assister SD-7” manufactured by DIC Corporation) were uniformly mixed to obtain a urethane resin composition (1).

(Example 2)
Instead of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 33.3 parts by mass of the N-coconut oil fatty acid alanine triethanolamine aqueous solution (non-volatile content 30% by mass) (N-coconut oil fatty acid alanine tri Except having used 10 mass parts) as ethanolamine, it carried out similarly to Example 1 and obtained the urethane resin composition (2).

(Example 3)
In place of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 33.3 parts by mass of N-lauroylalanine triethanolamine aqueous solution (non-volatile content 30% by mass) (10 as N-lauroylalanine triethanolamine) Except having used (mass part), it carried out similarly to Example 1 and obtained the urethane resin composition (3).

Example 4
In place of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 33.3 parts by mass of N-lauroyl sarcosine sodium aqueous solution (non-volatile content 30% by mass) (10 parts by mass as N-lauroyl sarcosine sodium) Except having used, it carried out similarly to Example 1 and obtained the urethane resin composition (4).

(Comparative Example 1)
Instead of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 14.3 parts by mass of a sodium dioctylsulfosuccinate aqueous solution (non-volatile content 70% by mass) (10 parts by mass as sodium dioctylsulfosuccinate) was used. Except for this, the same procedure as in Example 1 was carried out to obtain a urethane resin composition (R1).

(Comparative Example 2)
Instead of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 25 parts by mass of a lauryl sulfate triethanolamine aqueous solution (non-volatile content 40% by mass) (10 parts by mass as lauryl sulfate triethanolamine) was used. Except for this, the same procedure as in Example 1 was carried out to obtain a urethane resin composition (R2).

(Comparative Example 3)
Instead of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1, 16.7 parts by mass of polyoxyethylene alkyl ether aqueous solution (nonvolatile content 60% by mass) having an HLB of 18.5 (polyoxyethylene alkyl ether) As in Example 1, except that 10 parts by mass) was used, a urethane resin composition (R3) was obtained.

(Comparative Example 4)
A urethane resin composition (R4) was obtained in the same manner as in Example 1 except that 23.3 parts by mass of water was used instead of the N-coconut oil fatty acid sarcosine triethanolamine aqueous solution used in Example 1. .

  Using the urethane resin compositions (1) to (4) and (R1) to (R4) obtained in Examples 1 to 4 and Comparative Examples 1 to 4, a porous sheet was prepared as follows. Then, confirmation of the aggregation state of carbon black and evaluation of the foamed shape of the porous sheet were performed.

[Measurement of acid dissociation constant (pKa)]
An acid group such as a carboxyl group before neutralization with a base serving as a raw material for an anionic surfactant such as N-coconut oil fatty acid sarcosine triethanolamine used in Examples 1 to 4 and Comparative Examples 1 to 4 above. About the compound which has, it measured using the potentiometric automatic titrator ("AT-510" by Kyoto Electronics Industry Co., Ltd.), and calculated | required the value of the acid dissociation constant (pKa).

[Preparation of perforated sheet]
A urethane resin composition is applied to the surface of a polyethylene terephthalate film having a thickness of 0.1 mm so that the applied film thickness becomes 1.2 mm, and then the applied material is immersed in water adjusted to 25 ° C. for 10 minutes. Components insoluble in water contained in the liquid were solidified. Next, it was immersed in warm water adjusted to 50 ° C. to extract and remove water-soluble components contained in the solidified product, and then dried for 20 minutes with a hot air dryer adjusted to 100 ° C. to obtain a porous sheet.

[Confirmation of carbon black aggregation]
The inner surface of the foamed portion in the vicinity of the surface of the porous sheet obtained above (the surface in contact with water in the production process) was magnified 10,000 times with a scanning electron microscope ("JSM-6390LA" manufactured by JEOL Ltd.). The presence or absence of carbon black aggregation was observed, and from the results, the aggregation state of carbon black was evaluated according to the following criteria. In the photograph shown in FIG. 2, the particles appearing whitish are aggregates of carbon black.
○: There is no aggregate of carbon black.
Δ: Slightly aggregated carbon black.
X: There is an aggregate of carbon black.

[Evaluation of foaming state of porous sheet]
The porous sheet obtained above was cut into 5 cm square, and the polyethylene terephthalate film was peeled off. The density was calculated by measuring the thickness at the four corners and the center at five locations and taking the average value as the thickness of the porous sheet, measuring the mass and dividing by the area and thickness of the porous sheet. From the obtained density value, the foamed state of the porous sheet was evaluated according to the following criteria. In addition, the cross section of the porous sheet was observed with a scanning electron microscope (“JSM-6390LA” manufactured by JEOL Ltd.) at a magnification of 100 times.
○: The density is less than 0.20 g / cm ³ .
Δ: Density is 0.20 g / cm ³ or more and less than 0.25 g / cm ³ .
X: Density is 0.25 g / cm ³ or more.

  Table 1 shows the compositions and evaluation results of the urethane resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 4. In the composition shown in Table 1, the urethane resin, the surfactant, and the wet film-forming auxiliary are described in terms of nonvolatile content.

From the evaluation results shown in Table 1, those of Examples 1 to 4 which are the urethane resin compositions of the present invention have no carbon black aggregate in the porous sheet, and the density of the porous sheet is 0.20 g / cm. It was confirmed that the foamed state was good at less than ³ .

On the other hand, Comparative Examples 1 and 2 are examples of urethane resin compositions using an anionic surfactant obtained by neutralizing a compound having an acid group whose acid dissociation constant (pKa) is outside the range of 0 to 6 with a base. However, the porous sheet produced by using this urethane resin composition has a problem that although the density is less than 0.20 g / cm ³ and the foamed state is good, there is an aggregate of carbon black in the porous sheet. .

Comparative Example 3 is an example of a urethane resin composition using a nonionic surfactant. A porous sheet produced using this urethane resin composition has no carbon black aggregate but has a density of 0.00. There was a problem that it was as high as 24 g / cm ³ and the foamed state was poor.

Comparative Example 4 is an example of a urethane resin composition that does not use a surfactant. The porous sheet produced using this urethane resin composition has no carbon black aggregate, but has a density of 0.26 g / There was a problem that it was as high as cm ³ and the foamed state was poor.

Claims (3)

Urethane resin (A), carbon black (B), anionic amino acid surfactant (C) having a neutralized salt of an acid group having an acid dissociation constant (pKa) in the range of 0 to 6, and N, N- A urethane resin composition comprising dimethylformamide (D). The urethane resin composition according to claim 1, wherein the anionic amino acid surfactant (C) is an alkali metal salt, amine salt or ammonium salt of N-fatty acid acylamino acid. With claim 1 or 2 urethane resin composition according, perforated sheet, characterized in that obtained by wet coating method using water as a non-solvent.