JP2012102182A - Urethane resin composition for wet film formation, porous body and polishing pad obtained using the resin composition, and methods of manufacturing them - Google Patents

Abstract

The problem to be solved by the present invention is that it has excellent flexibility, a characteristic that a hole can be restored to its original shape and size when released from pressure, and is left in a humid heat environment for a certain period of time. Even in such a case, it is to provide a urethane resin composition that can form a porous body having a level of durability that can maintain the above characteristics, and that is suitable for processing by a wet film forming method.
The present invention relates to a urethane resin (A) obtained by reacting a polyol (a1) containing an aliphatic polyester polyol and a polyisocyanate (a2) containing an aromatic polyisocyanate, a carbodiimide compound (B), and It is the urethane resin composition for wet film-forming containing an organic solvent (C), Comprising: The said carbodiimide compound (B) is 0.1 mass part-5 mass parts with respect to 100 mass parts of said urethane resins (A). It is related with the urethane resin composition for wet film-forming characterized by being contained in the range, a porous body, a polishing pad, and its manufacturing method.
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Description

  The present invention relates to a urethane resin composition that can be used in various fields including, for example, leather-like sheets such as synthetic leather and artificial leather, moisture-permeable waterproof materials, and polishing pads, and is suitable exclusively for processing by a wet film forming method. .

  Since the polyurethane resin composition can form a film having good flexibility and strength, it has been conventionally used in various applications such as an adhesive, a coating agent, and a molding material. Among these, polyurethane resin compositions make use of their good flexible texture, for example, for the production of porous bodies used for clothing, moisture-permeable waterproof materials, polishing pads, etc., including leather-like sheet interlayers and skin layers. It is preferably used.

  Conventionally, a dry method and a wet method are known as a method for producing a porous body using the polyurethane resin composition.

  As a method for forming a porous body by the dry method, for example, an organic medium having a boiling point of 120 ° C. or less and water solubility at 25 ° C. of 1 to 50 g, a polyurethane polymer having a predetermined amount of polyoxyethylene groups, and water There is known a method of forming a microporous sheet by contacting a base material coated with a water-in-oil mixed dispersion composed of, for example, with a specific coagulant for a short time (for example, Patent Document 1). reference.).

  However, the dry method is usually not a preferable method from the viewpoint of reducing the environmental load recently because it is difficult to recover the organic solvent used for the production of the porous body. In addition, the porous body obtained by the dry method is not sufficient in terms of flexibility because it is difficult to form relatively large pores and it is difficult to reduce the density of the porous body.

  On the other hand, as a method for forming a porous body by a wet method, for example, a resin compounded liquid containing a urethane resin for moisture-permeable waterproofing, dimethylformamide, a crosslinking agent, and the like is applied on a base material, and in a 10% aqueous solution of dimethylformamide There is known a method of manufacturing a wet waterproof fabric that is immersed in and solidified (see, for example, Patent Document 2). The wet method is a suitable method for producing a porous body because the organic solvent recovery means used for the production of the porous body is established to some extent and can prevent the occurrence of pinholes and skinning on the surface of the obtained porous body. It is implemented for various purposes.

However, even when the ether-based urethane resin specifically described in Patent Document 2 is used, a porous body having large pores and good flexibility may not be formed. In addition, when the pressure is applied to the porous body, the porous body is left in a compressed state for a certain period, and then released from the pressure, the pores do not recover to the original shape and size, and the porous body There was a problem in that the thickness decreased with time.
On the other hand, when the porous body is produced, a crosslinking agent may be used in combination with the ether-based urethane resin, and various crosslinking agents such as an isocyanate-based crosslinking agent are known.
However, when an isocyanate-based crosslinking agent is used as the crosslinking agent, a porous body cannot be formed, or even if it can be formed, it is very hard and does not have the excellent flexibility and the like that are the problems of the present invention.

  In particular, the polishing pad is required to have a level of flexibility corresponding to the surface shape of the object to be polished, and characteristics that allow the holes to recover to their original shape and size when released from pressure. Further, the polishing pad may be deteriorated due to frictional heat and moisture during polishing, temperature or humidity during inventory, specifically, when the porous body is released from pressure. There is a need for a level of durability that does not cause degradation of the properties that allow the holes to recover to their original shape and size.

  However, the compositions described in Documents 1 and 2 may not provide a level of flexibility and durability that can be used for the polishing pad application, for example. Therefore, development of the urethane resin composition which can form the porous body which can make them compatible is calculated | required.

Japanese Patent Laid-Open No. 51-41063 JP 2007-169486 A

  The problems to be solved by the present invention are excellent flexibility, characteristics that the hole can recover to its original shape and size when released from pressure, and when left in a humid heat environment for a certain period of time. Even if it exists, it is providing the urethane resin composition suitable for the process by the wet film-forming method which can form the porous body provided with the durability of the level which can maintain the said characteristic.

  As a result of studying to solve the above problems, the present inventors processed a urethane resin composition containing a urethane resin having a specific ester structure, a specific crosslinking agent, and an organic solvent by a wet film forming method. It has excellent flexibility, characteristics that allow the pores to recover to their original shape and size when released from pressure, and the above characteristics even when left in a humid heat environment for a certain period of time. It has been found that a porous body or the like having a sustainable level of durability can be produced.

  That is, the present invention relates to a urethane resin (A), a carbodiimide compound (B), and an organic solvent obtained by reacting a polyol (a1) containing an aliphatic polyester polyol with a polyisocyanate (a2) containing an aromatic polyisocyanate. It is the urethane resin composition for wet film-forming containing (C), Comprising: The said carbodiimide compound (B) is 0.1 mass part-5 mass parts with respect to 100 mass parts of said urethane resins (A). The present invention relates to a urethane resin composition for wet film formation, a porous body, a polishing pad, and a method for producing the same.

  The “porous” of the porous body obtained in the present invention has a large number of pores that are naturally obtained by solidifying the urethane resin composition by a wet method and flexibility due to the pores. It means that.

  If it is the urethane resin composition of the present invention, by processing it by a wet film forming method, it has excellent flexibility and characteristics that allow the holes to recover to their original shape and size when released from pressure. A compatible porous body can be formed. The porous body is, for example, a skin layer or an intermediate layer of a leather-like sheet such as synthetic leather or artificial leather used for clothing, vehicle seats, furniture sheets, shoes, bags, etc., a polishing pad, a polishing back pad, a surgical garment, Medical hygiene materials such as bed sheets, building material sheets such as windproof and waterproof sheets and anti-condensation sheets, packaging materials such as desiccants, dehumidifiers and fragrances, agricultural sheets, various separators, packing, etc. It can be used for various applications such as skin layers.

  In the present invention, a urethane resin (A), a carbodiimide compound (B), an organic solvent (C) obtained by reacting a polyol (a1) containing an aliphatic polyester polyol with a polyisocyanate (a2) containing an aromatic polyisocyanate. ), And other additives as necessary, wherein the carbodiimide compound (B) is 0.1 to 5 parts by mass with respect to 100 parts by mass of the urethane resin (A). Of the urethane resin composition contained in the range of parts, it can be suitably used exclusively for processing by a wet film-forming method.

  Here, in the wet film forming method, the urethane resin composition for wet film forming is applied or impregnated on the surface of a base material, and then the urethane or the like is brought into contact with the application surface or the impregnated surface. This is a method for producing a porous body by solidifying the resin (A).

  The urethane film composition for wet film formation of the present invention can be suitably used exclusively when producing a porous body by the wet film formation method. In particular, excellent flexibility, characteristics that allow holes to recover to their original shape and size when released from pressure, and the above characteristics can be maintained even when left in a humid heat environment for a certain period of time. When a porous body having a certain level of durability is produced by the wet film-forming method, it can be suitably used.

  As the urethane resin (A), it is essential to use a urethane resin obtained by reacting a polyol (a1) containing an aliphatic polyester polyol and a polyisocyanate (a2) containing an aromatic polyisocyanate.

  Here, instead of the urethane resin (A), for example, a urethane resin composition obtained by using a urethane resin obtained by reacting a polyether polyol such as polyoxytetramethylene glycol and an aromatic polyisocyanate. Then, there are cases where a porous body having excellent flexibility cannot be formed.

  Further, in place of the urethane resin (A), a urethane resin composition obtained by using a urethane resin obtained by reacting a polyol (a1) containing an aliphatic polyester polyol and an aliphatic polyisocyanate is flexible. In some cases, a porous body having excellent properties cannot be formed.

  As said urethane resin (A), it is preferable to use what has a weight average molecular weight of 5000-500000, It is more preferable to use what has a weight average molecular weight of 50000-300000, The weight average of 100,000-250,000 Use of a material having a molecular weight is more preferable in terms of improving the durability of the porous body and improving the ease of processing of wet film formation.

  As the polyol (a1) that can be used for the production of the urethane resin (A), an aliphatic polyester polyol can be used as an essential component, and other polyols can be used in combination as required.

  As the aliphatic polyester polyol, those obtained by esterifying an aliphatic polyol and an aliphatic polycarboxylic acid can be used.

  Examples of the aliphatic 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-cyclohexanedimethanol, polyethylene glycol (Range of number average molecular weight 300-6000), polypropylene glycol (range of number average molecular weight 300-6000), ethylene oxide-propylene oxide copolymer (range of number average molecular weight 300-6000) ); Hydrogenated bisphenol A and alkylene oxide adducts thereof; trimethylolpropane, may be used trimethylolethane, pentaerythritol, sorbitol and the like.

  Examples of the polycarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, todecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like. An anhydride or ester-forming derivative of polycarboxylic acid can be used.

  As the aliphatic polyester polyol, one or more aliphatic polyols selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and 1,4-butanediol are used for forming a flexible porous body by a wet film forming method. And an aliphatic polycarboxylic acid containing adipic acid are preferably used.

  As said aliphatic polyester polyol, when forming a flexible porous body by a wet film-forming method, it is preferable to use what has a number average molecular weight of 500-5000, and what uses 1000-3500 is used. More preferred.

  Moreover, as said aliphatic polyester polyol, the polyester obtained by ring-opening polymerization reaction of cyclic ester compounds, such as (epsilon) -caprolactone, these copolyesters, etc. can also be used.

  The aliphatic polyester polyol may be used in the range of 40% by mass to 85% by mass with respect to the total mass of the polyol (a1) and the polyisocyanate (a2) used in the production of the urethane resin (A). It is preferable when forming a flexible porous body by a wet film-forming method.

  Moreover, as said polyol (a1), in addition to the said aliphatic polyester polyol, another polyol can be further used as needed.

  As the other polyols, aromatic polyester polyols, polyether polyols, polycarbonate polyols, and the like can be used. From the viewpoint of forming a flexible porous body by a wet film forming method, the amount used is the above polyol. It is preferable that it is 30 mass% or less with respect to the whole quantity of (a1).

  Examples of the aromatic polyester polyol include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis (phenoxy) ethane. -A product obtained by esterifying an aromatic polycarboxylic acid such as p, p'-dicarboxylic acid and an aromatic polyol such as bisphenol A, and those aliphatic polyols and aliphatic polycarboxylic acids. Those obtained by a combined esterification reaction can be used.

  Examples of the polyether polyol that can be used for the other 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 initiator include propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, diglycerin, trimethylolethane, and trimethylol. Propane, water, hexanetriol and the like can be used.

  Examples of the alkylene oxide include propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

  Examples of the polycarbonate polyol obtained by esterifying carbonic acid with an aliphatic polyhydric alcohol include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and polyethylene. Reaction products of diols such as glycol, polypropylene glycol or polytetramethylene glycol (PTMG) and cyclic carbonates such as dimethyl carbonate and ethylene carbonate Is mentioned.

  In addition, as other polyols that can be used for the polyol (a1), a polyol having a relatively low molecular weight of about 40 to 200 that has been conventionally used for a chain extender can be used. For example, ethylene glycol 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 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 glycol, glycerin, trimethylol propane, sorbitol, hydroquinone diethylol ether, etc. Polyhydric alcohol, amine compound, amino acid Alkanolamines, it can be used silicone-modified compounds, it is preferred to use ethylene glycol or 1,4-butanediol.

  The relatively low molecular weight polyol is preferably used in the range of 3% by mass to 30% by mass with respect to the total amount of the polyol (a1) when forming a flexible porous body by a wet film forming method.

  Moreover, as polyisocyanate (a2) used for manufacture of the said urethane resin (A), aromatic polyisocyanate can be made into an essential component, and another polyisocyanate can be combined and used as needed.

  Examples of the aromatic polyisocyanate include 1,3- and 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate (2,4-TDI), and 1-methyl-2,6-phenylene diisocyanate. (2,6-TDI), 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 (4,4-MDI , Diphenylmethane-2,2'-diisocyanate (2,2-MDI), may be used diphenylmethane-2,4-diisocyanate (2,4-MDI) and the like.

  Among them, the use of diphenylmethane-4,4′-diisocyanate (4,4-MDI) is a flexible material having excellent characteristics that the pores can be restored to their original shape and size when released from pressure. It is preferable when forming a porous body.

  Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di (isocyanate methyl) cyclohexane, 1,4-di (isocyanate methyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (4 4H-MDI), 2,4′-dicyclohexylmethane diisocyanate (2,4-H-MDI), 2,2′-dicyclohexylmethane diisocyanate Isocyanate (2,2-H-MDI), 3,3'- dimethyl-4,4'-dicyclohexylmethane diisocyanate and these trimers and the like can be used.

  The urethane resin (A) can be produced, for example, by mixing and reacting the polyol (a1) and the polyisocyanate (a2) in the absence of a solvent or in the presence of an organic solvent (C) described later. .

  When the relatively low molecular weight polyol is used as a chain extender when the urethane resin (A) is produced, the chain extender is used when mixing the polyol (a1) and the polyisocyanate (a2). The polyol (a1) and the polyisocyanate (a2) are reacted to produce a urethane prepolymer having an isocyanate group at the molecular end, and then the urethane prepolymer and the chain extender are mixed. And may be reacted.

  In the reaction of the polyol (a1) and the polyisocyanate (a2), the equivalent ratio [isocyanate group / hydroxyl group] of the hydroxyl group of the polyol (a1) and the isocyanate group of the polyisocyanate (a2) is 0.8. It is preferable that it is the range of -1.2, and it is more preferable that it is 0.9-1.1.

  The urethane resin (A) obtained by the above method is preferably dissolved or dispersed in the organic solvent (C), and part or all of the urethane resin (A) is dissolved in the organic solvent (C). It is preferable.

Next, the carbodiimide compound (B) used in the present invention will be described.
The carbodiimide compound (B) is an essential component for imparting good flexibility to the resulting porous body and characteristics that allow the pores to recover to their original shape and size when released from pressure. It is important to use within a range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the urethane resin (A).

  Here, if the amount used is less than 0.1 parts by mass, the effect of using the carbodiimide compound (B) cannot be obtained, and if the amount used exceeds 5 parts by mass, it is formed by a wet film forming method. In some cases, the cell holes of the porous body are easily crushed during the processing, and the hole shape cannot be maintained.

  Therefore, it is essential to use the carbodiimide compound (B) within the above range, and it is particularly preferable to use the carbodiimide compound (B) in the range of 0.3 to 3 parts by mass.

  The carbodiimide compound (B) used in the present invention is preferably obtained by a polyisocyanate and a condensation reaction involving decarbonization.

  Examples of the polyisocyanate used for the production of the carbodiimide compound (B) include tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di (isocyanate methyl) cyclohexane, 1,4-di (isocyanate methyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate (IPDI), 4,4 '-Dicyclohexylmethane diisocyanate (4,4H-MDI), 2,4'-dicyclohexylmethane diisocyanate (2,4-H-MDI) 2,2′-dicyclohexylmethane diisocyanate (2,2-H-MDI), 3,3′-dimethyl-4,4′-dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 1,3- and 1 , 4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate (2,4-TDI), 1-methyl-2,6-phenylene diisocyanate (2,6-TDI), 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-fur Nylene 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 (4,4-MDI), diphenylmethane-2,2′- Diisocyanate (2,2-MDI), diphenylmethane-2,4-diisocyanate (2,4-MDI) and the like can be used.

  The condensation reaction involving decarbonization of the polyisocyanate is a reaction between two isocyanate groups, and is a reaction for forming a bond (—N═C═N—). At that time, carbon dioxide is generated.

  The reaction can be performed, for example, by stirring the polyisocyanate while heating at 100 to 200 ° C. in the presence of an organophosphorus catalyst, and removing carbon dioxide together with a nitrogen stream to the outside of the reaction system.

As the carbodiimide compound (B), it is possible to use xylylene diisocyanate or tetramethyl xylylene diisocyanate as the polyisocyanate, and to use a decarbonized condensate thereof as a width in the plane direction of the porous body (thickness direction). It is preferable at the point from which the porous body which formed the hole developed long was obtained. A porous body formed with a hole that has developed long in the width (thickness direction) in the surface direction of the porous body has an appropriate elasticity together with excellent flexibility, and when the hole is released from the pressure, Since it has a property that can be restored to its size, it can be suitably used for applications such as a polishing pad.
As the carbodiimide compound (B), specifically, poly [phenylenebis (dimethylmethylene) carbodiimide], poly (methyl-1,3-phenylenecarbodiimide), or the like can be used. As the carbodiimide compound (B), for example, Carbodilite V-07 or V-09 manufactured by Nisshinbo Chemical Co., Ltd. can be used.

  In addition, as the carbodiimide compound (B), in order to obtain a flexible porous body having a low density by wet film formation, a compound having a number average molecular weight of about 1000 to 5000 and generally called an oligomer or polymer may be used. preferable.

Next, the organic solvent (C) used in the present invention will be described.
In the present invention, N, N-dimethylformamide, N, N-dimethylacetamide, N, is used as the organic solvent (C) used when producing the porous body by the wet film formation method using the urethane resin (A) or the like. -Ketone solvents such as methyl-2-pyrrolidone, methyl ethyl ketone, methyl-n-propyl ketone, acetone, methyl isobutyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, An ester solvent such as isobutyl acetate and sec-butyl acetate can be used.

  Especially, it is preferable to use N, N-dimethylformamide because the solubility of the urethane resin and the solubility in water are high, and it is easy to remove by drying with hot air. As the organic solvent (C), it is particularly preferable to use one containing 70% by mass or more of N, N-dimethylformamide based on the total amount of the organic solvent (C).

  The organic solvent (C) can also be used as a reaction solvent when the urethane resin (A) is produced.

  The organic solvent (C) is preferably used in a range of 200% by mass to 900% by mass with respect to the total amount of the urethane resin (A) and the carbodiimide compound (B) used in the present invention, 300 More preferably, it is in the range of mass% to 700 mass%.

  The urethane resin composition for wet film formation used in the present invention is produced, for example, by mixing the urethane resin (A) produced in the absence of a solvent, the carbodiimide compound (B), and the organic solvent (C). can do. In the case where a mixture of the urethane resin (A) and the organic solvent (B) is produced by reacting the polyol (a1) with the polyisocyanate (a2) in the presence of the organic solvent (C). A mixture of the mixture and the carbodiimide compound (B) can be used.

  The wet film-forming urethane resin composition may contain other additives as necessary in addition to the above-described ones.

  The additive may be colored with, for example, an organic pigment or an inorganic pigment, and further contains a brominated flame retardant, a chlorinated flame retardant, a plasticizer, a softening agent, a stabilizer, a wax, an extinguishing agent, if necessary. Usual foaming agents, dispersants, penetrants, surfactants, various fillers, antifungal agents, antibacterial agents, ultraviolet absorbers, antioxidants, weathering stabilizers, fluorescent brighteners, anti-aging agents, thickeners, etc. The additive to be used can be used in the range which does not inhibit the effect of this invention.

  Examples of a method for producing a porous body by a wet film-forming method using the wet-formed film-forming urethane resin composition obtained by the above method include, for example, applying or impregnating the wet film-forming urethane resin composition to a substrate surface Next, by bringing water or water vapor into contact with the coated surface, the urethane resin (A) contained in the urethane resin composition is solidified by a wet method to form a porous body, and then porous as necessary. The method of manufacturing by wash | cleaning and drying the body surface using water or warm water is mentioned.

  As a substrate on which the wet film-forming urethane resin composition is applied, a non-woven fabric, a woven fabric, a knitted substrate, a resin film, or the like can be used. As the material constituting the base material, for example, polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, polylactic acid fiber, cotton, hemp, silk, wool, blended fiber thereof or the like is used. can do.

  The surface of the base material may be subjected to antistatic processing, mold release processing, water repellent processing, water absorption processing, antibacterial and deodorizing processing, antibacterial processing, ultraviolet blocking processing, and the like as necessary.

  Examples of a method for applying or impregnating the wet film-forming urethane resin composition on the surface of the substrate include a gravure coater method, a knife coater method, a pipe coater method, and a comma coater method. At that time, from the viewpoint of adjusting the viscosity of the urethane resin composition and improving the coating workability and the like, the amount of the organic solvent (C) used may be adjusted as necessary.

  The film thickness of the coating film made of the urethane resin composition for wet film formation applied or impregnated by the above method is preferably about 0.5 mm to 5.0 mm, more preferably about 0.5 mm to 3 mm. preferable.

  As a method of bringing water or water vapor into contact with the coated surface formed by applying or impregnating the urethane film composition for wet film formation, for example, a substrate provided with a coating layer or an impregnation layer made of the urethane resin composition is used as a water bath. Examples thereof include a method of immersing in water and a method of spraying water on the coated surface using a spray or the like. The immersion is preferably performed in a water bath at about 5 to 60 ° C. for about 2 to 20 minutes.

  If necessary, the porous body formed by the above method is preferably washed at room temperature with water or hot water to extract and remove the organic solvent (C), and then dried. The washing is preferably performed with water at about 5 to 60 ° C. for about 20 to 120 minutes, and the water used for washing is preferably replaced at least once or continuously with running water. The drying is preferably performed for about 10 to 60 minutes using a dryer or the like adjusted to about 80 to 120 ° C.

  The porous body obtained by the above method has a spindle-shaped or teardrop-shaped porous structure that is long in the thickness direction of the surface. The size of the hole can be appropriately adjusted according to the use, but from the viewpoint of achieving both excellent flexibility and durability, the hole has a diameter of 1 μm to 10 μm at the largest width (thickness direction). It is preferable. Since the porous body obtained in the present invention has pores that are long in the thickness direction and uniform in diameter in the surface direction, it is flexible and has an appropriate elasticity against compression in the thickness direction. It can be suitably used as a pad. The thickness of the porous body is preferably a relatively thick film of about 0.45 mm to 1.0 mm, which is suitable for use in applications such as a polishing pad, and is 0.45 mm to 0.7 mm. Is more preferable.

  As described above, the porous body obtained by using the urethane resin composition for wet film formation according to the present invention can achieve both excellent flexibility and durability such as hydrolysis resistance and alkali resistance. Leather-like sheets such as synthetic leather and artificial leather used for clothing, vehicle seats, furniture sheets, shoes, bags, etc., polishing pads, medical hygiene materials such as surgical clothes and bed sheets, windproof / waterproof sheets, anti-condensation sheets, etc. Sheets for building materials, packaging materials such as desiccants, dehumidifiers and fragrances, intermediate layers constituting agricultural sheets, various separators, packings, etc. can be used for various applications such as skin layers.

  Among them, the porous body of the present invention is used as a polishing pad used for polishing and fixing an object in flattening applications such as glass and metal for hard disk platters, glass for flat panel displays, and silicon wafers. It can be preferably used.

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

[Example 1]
102.7 parts by mass of polyester diol (number average molecular weight 2000) obtained by reacting ethylene glycol and adipic acid in a reaction apparatus having a stirrer, a condenser reflux, and a thermometer, 1,4-butanediol and adipic acid 102.7 parts by mass of a polyester diol (number average molecular weight 3000) obtained by reacting with benzene, 14.4 parts by mass of ethylene glycol, 699.0 parts by mass of N, N-dimethylformamide and 4,4′-diphenylmethane 80.2 parts by mass of diisocyanate was added and allowed to react at 60 ° C. for 6 hours with stirring. Subsequently, 1.0 part by mass of isopropyl alcohol was added and further stirred at 60 ° C. for 1 hour. I).
The urethane resin (i) solution (I) has a non-volatile content of 30% by mass and a viscosity of 55 Pa · s. The weight average molecular weight of the urethane resin (i) by gel permeation chromatography using polystyrene as a standard sample was 151,000. It was.

  333 parts by mass of urethane resin (i) solution (I), 2 parts by mass of N, N-dimethylformamide solution (non-volatile content 50% by mass) of poly [phenylenebis (dimethylmethylene) carbodiimide], N, N-dimethylformamide 222 parts by mass, 33 parts by weight of Dirac L-5442 (manufactured by DIC Corporation) as an inorganic pigment, 9 parts by mass of Crisbon Assistor SD-7 (manufactured by DIC Corporation) as a surfactant, and Crisbon Assistor SD- 11 (DIC Corporation) was mixed with 6 parts by mass to obtain a urethane resin composition for wet film formation (1).

(Preparation of porous material)
On the surface of a polyethylene terephthalate film having a thickness of 0.25 mm, the urethane resin composition for wet film formation (1) is applied using a film applicator so that the coating film thickness is about 1.2 mm, and then the coating is performed. The urethane resin (i) contained in the wet film-forming urethane resin composition (1) was wet-coagulated by immersing the product in water adjusted to 25 ° C. for 10 minutes.

  Next, the surface of the coated product is washed by immersing it in warm water adjusted to 50 ° C. for 120 minutes, and then dried for 20 minutes using a hot air dryer adjusted to 100 ° C., so that it is applied onto a polyethylene terephthalate film. The formed porous body (1) was obtained.

(Preparation of polishing pad)
A polishing pad (1) was obtained by applying a double-sided tape (DaiTac 8800HC (manufactured by DIC Corporation)) to the back surface of the polyethylene terephthalate film constituting the porous body (1) obtained above.

[Example 2]
95.9 parts by mass of polyester diol (number average molecular weight 2000) obtained by reacting 1,6-hexanediol and adipic acid in a reaction apparatus having a stirrer, a condenser reflux, and a thermometer, 1,6-hexane 95.9 parts by mass of polyester diol (number average molecular weight 3000) obtained by reacting diol with adipic acid, 28.0 parts by mass of 1,6-hexanediol, and 699.0 parts by mass of N, N-dimethylformamide 80.1 parts by mass of 4,4′-diphenylmethane diisocyanate were mixed and reacted at 60 ° C. for 6 hours with stirring. Then, 1.0 part by mass of isopropyl alcohol was added and further stirred at 60 ° C. for 1 hour. A solution (II) of urethane resin (ii) was obtained.
The urethane resin (ii) solution (II) had a nonvolatile content of 30% by mass, a viscosity of 45 Pa · s, and a weight average molecular weight of 145,000 using polystyrene as a standard sample by gel permeation chromatography. Moreover, the urethane resin composition for wet film-forming (in the same way as Example 1 except using a urethane resin (ii) solution (II) instead of the said urethane resin (i) solution (I) ( 2) A porous body (2) and a polishing pad (2) were obtained.

[Example 3]
333 parts by mass of urethane resin (i) solution (I), 8 parts by mass of N, N-dimethylformamide solution (non-volatile content 50% by mass) of poly [phenylenebis (dimethylmethylene) carbodiimide], N, N-dimethylformamide 222 parts by mass, 33 parts by weight of Dirac L-5442 (manufactured by DIC Corporation) as an inorganic pigment, 9 parts by mass of Crisbon Assistor SD-7 (manufactured by DIC Corporation) as a surfactant, and Crisbon Assistor SD- A urethane resin composition for wet film formation (3) was obtained by mixing 6 parts by mass of 11 (manufactured by DIC Corporation). Further, the porous body (3) was prepared in the same manner as in Example 1 except that the wet film-forming urethane resin composition (3) was used instead of the wet film-forming urethane resin composition (1). And the polishing pad (3) was obtained.

[Example 4]
333 parts by mass of the urethane resin (i) solution (I), 2 parts by mass of a toluene solution (non-volatile content: 50% by mass) of poly (methyl-1,3-phenylenecarbodiimide), and 222 parts by mass of N, N-dimethylformamide 33 parts by weight of Dirac L-5442 (manufactured by DIC Corporation) as an inorganic pigment, 9 parts by weight of Crisbon Assister SD-7 (manufactured by DIC Corporation) as a surfactant, and Crisbon Assister SD-11 (DIC stock) A urethane resin composition (4) for wet film formation was obtained by mixing 6 parts by mass of (manufactured by company). Further, the porous body (4) was prepared in the same manner as in Example 1 except that the wet-form urethane resin composition (4) was used instead of the wet-form urethane resin composition (1). And the polishing pad (4) was obtained.

[Comparative Example 1]
333 parts by mass of urethane resin solution (I), 222 parts by mass of N, N-dimethylformamide, 33 parts by weight of Dirac L-5442 (manufactured by DIC Corporation) as an inorganic pigment, and Crisbon Assister SD- as a surfactant 9 parts by mass (made by DIC Corporation) and 6 parts by mass of Crisbon Assister SD-11 (made by DIC Corporation) were mixed to obtain a urethane resin composition for wet film formation (1 ′). Further, in place of the wet film forming urethane resin composition (1), the porous body (1) was prepared in the same manner as in Example 1 except that the wet film forming urethane resin composition (1 ′) was used. ') And a polishing pad (1') were obtained.

[Comparative Example 2]
333 parts by mass of the urethane resin solution (I), 1.3 parts by mass of an ethyl acetate solution (non-volatile content 75% by mass) of an adduct of methyl-1,3-phenylene diisocyanate, and 222 parts by mass of N, N-dimethylformamide 33 parts by weight of Dirac L-5442 (manufactured by DIC Corporation) as an inorganic pigment, 9 parts by weight of Crisbon Assister SD-7 (manufactured by DIC Corporation) as a surfactant, and Crisbon Assister SD-11 (DIC stock) 6 parts by mass of (made by company) was mixed to obtain a urethane resin composition for wet film formation (2 ′). Further, a porous body (2) was prepared in the same manner as in Example 1 except that the wet-form urethane resin composition (2 ′) was used in place of the wet-form urethane resin composition (1). ') And a polishing pad (2') were obtained. Since the porous body (2 ′) and the polishing pad (2 ′) have a fine pore structure, a thick porous body may not be formed. The porous body obtained in Example 1 or the like ( It was a thin film compared with 1) etc.

[Comparative Example 3]
In a reaction apparatus having a stirrer, a condenser reflux, and a thermometer, 102.7 parts by mass of polytetramethylene glycol (number average molecular weight 2000), 102.7 parts by mass of polytetramethylene glycol (number average molecular weight 3000), ethylene glycol 14.4 parts by mass, N, N-dimethylformamide 699.0 parts by mass, 4,4′-diphenylmethane diisocyanate 80.2 parts by mass, reacted at 60 ° C. for 6 hours with stirring, and then isopropyl alcohol was added. 1.0 part by mass was added and further stirred at 60 ° C. for 1 hour to obtain a solution (III) of urethane resin (iii).
The urethane resin (iii) solution (III) had a nonvolatile content of 30% by mass, a viscosity of 40 Pa · s, and a weight average molecular weight of 145,000 using polystyrene by gel permeation chromatography as a standard sample. Moreover, the urethane resin composition for wet film-forming (in the same way as Example 1 except using a urethane resin (iii) solution (III) instead of the said urethane resin (i) solution (I) ( 3 ′), a porous body (3 ′) and a polishing pad (3 ′) were obtained. Since the porous body (3 ′) and the like have a fine pore structure, a thick porous body may not be formed. Compared with the porous body (1) obtained in Example 1 or the like. It was a thin film.

[Comparative Example 4]
To a reactor having a stirrer, a condenser reflux, and a thermometer, 102.7 parts by mass of 1,6-hexanediol polycarbonate diol (number average molecular weight 2000) and 1,6-hexanediol polycarbonate diol (number average molecular weight 3000) 102.7 parts by mass, 14.4 parts by mass of ethylene glycol, 699.0 parts by mass of N, N-dimethylformamide, and 80.2 parts by mass of 4,4′-diphenylmethane diisocyanate, and 60 ° C. with stirring. Then, 1.0 part by mass of isopropyl alcohol was added and stirred at 60 ° C. for 1 hour to obtain a solution (IV) of urethane resin (iv). Urethane resin (iv) solution (IV) Is 30% by mass of non-volatile content, viscosity of 60 Pa · s, polystyrene standard gel permeation chromatography The weight average molecular weight was 145000. Moreover, the urethane resin composition for wet film-forming (in the same way as Example 1 except using a urethane resin (iv) solution (IV) instead of the said urethane resin (i) solution (I) ( 4 ′), porous body (4 ′) and polishing pad (4 ′) were obtained. Since the porous body (4 ′) and the like have a fine pore structure, a thick porous body may not be formed. Compared with the porous body (1) obtained in Example 1 or the like. It was a thin film.

[Comparative Example 5]
112.6 parts by mass of polyester diol (number average molecular weight 2000) obtained by reacting ethylene glycol and adipic acid in a reaction apparatus having a stirrer, a condenser reflux, and a thermometer, 1,4-butanediol and adipic acid 112.6 parts by mass of a polyester diol (number average molecular weight 3000) obtained by reacting with 1,15.8 parts by mass of ethylene glycol, 699.0 parts by mass of N, N-dimethylformamide, 1,6-hexamethylene 59.1 parts by mass of diisocyanate was added, reacted for 9 hours at 60 ° C. with stirring, then 1.0 part by mass of isopropyl alcohol was added, and further stirred for 1 hour at 60 ° C. to obtain a solution of urethane resin (i ′). (I ') was obtained. The solution (I ′) of the urethane resin (i ′) had a nonvolatile content of 30% by mass, a viscosity of 38 Pa · s, and a weight average molecular weight of 136000 using polystyrene by gel permeation chromatography as a standard sample.
Moreover, the urethane resin composition for wet film-forming is the same method as Example 1 except using a urethane resin (i ') solution (I') instead of the said urethane resin (i) solution (I). A product (5 ′), a porous body (5 ′) and a polishing pad (5 ′) were obtained. Since the porous body (5 ′) and the like have a fine pore structure, a thick porous body may not be formed. Compared with the porous body (1) obtained in Example 1 or the like. It was a thin film.

The evaluation of the flexibility of the polishing pad and the characteristics that the hole can recover to its original shape and size when released from the pressure, the characteristics are substantially formed, the urethane resin composition is solidified The porous body obtained by using the urethane resin composition for wet film formation in which the polyethylene terephthalate film and the double-sided tape were removed from the polishing pad obtained above because of the property of the porous layer formed. Used.
[Flexibility evaluation method]
The thickness of the porous body obtained above was measured using a thickness measuring device CR-10A (manufactured by Daiei Kagaku Seiki Seisakusho). The thickness was measured after being left for 1 minute in a state where a load of 1.96 kPa was applied to the porous body (thickness 1). Therefore, the thickness of the porous body obtained by the measurement shows a thickness in a state where a load of 1.96 kPa is applied.
Next, the thickness of the porous body after being allowed to stand for 1 minute in a state where a load of 23.5 kPa was applied was measured using a thickness measuring device similar to the above (thickness 2).
When the value of (Thickness 2) was 60% or less with respect to the value of (Thickness 1), it was evaluated as “◯”, and when it was 55% or less, it was evaluated as “「 ”. On the other hand, when the value of (thickness 2) exceeded 60% of the value of (thickness 1), it was evaluated as “Δ”, and particularly when it exceeded 70%, it was evaluated as “x”.

[Evaluation method for characteristics that allow holes to recover to their original shape and size when released from pressure (characteristic 1)]
The thickness of the porous body obtained above was measured using a thickness measuring device CR-10A (manufactured by Daiei Kagaku Seiki Seisakusho). The thickness was measured after being left for 1 minute in a state where a load of 1.96 kPa was applied to the porous body (thickness 1). Therefore, the thickness of the porous body obtained by the measurement shows a thickness in a state where a load of 1.96 kPa is applied.
Next, the thickness of the porous body after being left for 1 minute in a state where a load of 23.5 kPa was applied was measured using a thickness measuring device similar to the above (thickness 2).
Next, the load was returned to the initial 1.96 kPa, and the thickness of the porous body after being left for 1 minute was measured using the same thickness measuring instrument as described above (thickness 3).
When the value of (Thickness 3) is 95% or more with respect to the value of (Thickness 1), it is evaluated as “◎”, and when it is 90% or more and less than 95%, it is evaluated as “◯”. did. On the other hand, when the value of the (thickness 3) is 80% or more and less than 90% with respect to the value of the (thickness 1), it is evaluated as “Δ”, and particularly when the value is less than 80%, “x”. evaluated.

[Evaluation method for characteristics that allow pores to recover to their original shape and size when a porous body left in a humid heat environment is released from pressure (characteristic 2)]
The porous body obtained above was stored in a wet heat tester adjusted to 40 ° C. and 95% Rh for 7 days, and then dried for 4 hours using a hot air dryer adjusted to 40 ° C.
Subsequently, the thickness of the porous body which was allowed to stand for 20 hours in a room temperature environment at 25 ° C. was measured using a thickness measuring device CR-10A (manufactured by Daiei Scientific Instruments Co., Ltd.). The thickness was measured after being left for 1 minute in a state where a load of 1.96 kPa was applied to the porous body (thickness 4). Therefore, the thickness of the porous body obtained by the measurement shows a thickness in a state where a load of 1.96 kPa is applied.
Next, the thickness of the porous body after being left for 1 minute in a state where a load of 23.5 kPa was applied was measured using a thickness measuring device similar to the above (thickness 5).
Next, the load was returned to the initial 1.96 kPa, and the thickness of the porous body after being left for 1 minute was measured using a thickness measuring device similar to the above (thickness 6).
When the value of (Thickness 6) was 95% or more with respect to the value of (Thickness 3), it was evaluated as “◎”, and when it was 90% or more and less than 95%, it was evaluated as “◯”. did. On the other hand, when the value of (thickness 6) is 80% or more and less than 90% of the value of (thickness 3), it is evaluated as “Δ”, and particularly less than 80% is evaluated as “x”. evaluated.

Claims (8)

Contains urethane resin (A), carbodiimide compound (B) and organic solvent (C) obtained by reacting polyol (a1) containing aliphatic polyester polyol and polyisocyanate (a2) containing aromatic polyisocyanate. A wet film forming urethane resin composition, wherein the carbodiimide compound (B) is contained in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of the urethane resin (A). A urethane resin composition for wet film formation. The aliphatic polyester polyol is obtained by reacting an aliphatic polyol containing one or more selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and 1,4-butanediol with an aliphatic polycarboxylic acid containing adipic acid. The urethane resin composition for wet film formation according to claim 1, which is obtained by The urethane resin composition for wet film-forming according to claim 1, wherein the carbodiimide compound (B) contains a decarbonized condensate of xylylene diisocyanate or tetramethyl xylylene diisocyanate. The urethane resin composition for wet film-forming according to claim 1, wherein the organic solvent (C) contains 70% by mass or more of N, N-dimethylformamide with respect to the whole organic solvent (C). The porous body obtained by processing by the wet film-forming method using the urethane resin composition for wet film-forming of any one of Claims 1-4. A polishing pad obtained by processing the urethane resin composition for wet film formation according to any one of claims 1 to 4 by a wet film formation method. The urethane resin composition for wet film formation according to any one of claims 1 to 4 is applied or impregnated on a substrate surface, and then water or water vapor is brought into contact with the coated surface or the impregnated surface. A method for producing a porous body. The urethane resin composition for wet film formation according to any one of claims 1 to 4 is applied or impregnated on a substrate surface, and then water or water vapor is brought into contact with the coated surface or the impregnated surface. A method for producing a polishing pad.