Urethane resin composition and method for producing porous body

Abstract

The problem to be solved by the present invention is to provide a method for manufacturing a porous body with excellent wet film-forming properties and low compressibility. The present invention provides a carbamate resin composition, comprising a carbamate resin (A), a solvent (B) and a film-forming aid (C), wherein the film-forming aid (C) contains a hydrocarbon (c1) with a carbon number ranging from 8 to 18. In addition, the present invention provides a method for manufacturing a porous body, wherein the carbamate resin composition is subjected to wet film-forming. The content of the hydrocarbon (c1) is preferably in the range of 0.1 to 30 parts by mass relative to 100 parts by mass of the carbamate resin (A). The hydrocarbon (c1) is preferably an isoparaffin.

Description

Technical Field

[0001] The present invention relates to a urethane resin composition and a method for producing a porous body by a wet film-forming method. Background Art

[0002] Polishing pads using urethane resin compositions are widely used in fields requiring high surface flatness such as liquid crystal glass, hard disk glass, silicon wafers, and semiconductors. In the final finishing polishing, a soft porous body is used, which is processed by a wet film forming method in which a urethane resin diluted with a solvent such as dimethylformamide (DMF) is solidified in water (for example, see Patent Document 1).

[0003] The properties required of the polishing pad based on the porous body include, for example, a high bulk elastic modulus (= low compressibility) for maintaining the flatness of the surface of the processed body, the softness of the material for suppressing surface scratches, and the fineness and uniformity (wet film-forming properties) of the porous units for retaining the slurry (polishing liquid) and performing stable polishing.

[0004] However, the low compressibility, flexibility, and wet film-forming properties are contradictory physical properties. For example, when the compressibility of the polishing pad is reduced in order to emphasize flatness, the urethane resin becomes hard and scratches are aggravated. In addition, when the hardness of the urethane resin is reduced in order to emphasize scratch resistance, the solidification in water cannot proceed quickly, thereby losing the uniformity of the porous unit and causing instability in polishing. In this way, it is difficult to take all physical properties into consideration with a high balance.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] Japanese Patent Publication No. 2004-256738 Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] The problem to be solved by the present invention is to provide a method for producing a porous body having excellent wet film-forming properties and low compressibility.

[0010] [Technical means to solve the problem]

[0011] The present invention provides a urethane resin composition, comprising a urethane resin (A), a solvent (B) and a film-forming aid (C), wherein the film-forming aid (C) contains a hydrocarbon (c1) having a carbon number of 8 to 18.

[0012] In addition, the present invention provides a method for producing a porous body, comprising wet-forming the urethane resin composition.

[0013] [Effects of the Invention]

[0014] According to the present invention, by using a specific film-forming aid, a porous body with low compressibility and fine uniformity can be produced by a wet film-forming method. Therefore, the present invention is particularly suitable for the production of polishing pads, artificial leather, and synthetic leather.

[0015] In the present invention, the "porous body" refers to a porous structure having a large number of pores that can be naturally obtained when the urethane resin composition is solidified by a wet film-forming method, for example, a spindle-shaped or teardrop-shaped porous structure formed in the thickness direction of the surface. DETAILED DESCRIPTION

[0016] The present invention is a method for producing a porous body by wet-forming a urethane resin composition containing a urethane resin (A), a solvent (B) and a specific film-forming aid (C).

[0017] In the present invention, as a film-forming aid (C), a hydrocarbon (c1) having a carbon number of 8 to 18 must be contained. The hydrocarbon having a specific carbon number has moderately high hydrophobicity, so by adjusting the coagulation rate of the urethane resin in water, the substitution of DMF and water is eased, and the surface coagulation is suppressed, so that the porous unit can be miniaturized and uniform by wet film formation, and a porous body with low compressibility can be obtained. As the hydrocarbon, when a hydrocarbon having a carbon number of less than 8 is used, it is ineffective to suppress the surface coagulation rate, and a porous body with excellent low compressibility cannot be obtained. In addition, when a hydrocarbon having a carbon number of more than 18 is used, the hydrophobicity is too strong and the uniformity of the porous unit is poor. Furthermore, when a highly hydrophilic film-forming aid is used instead of the hydrocarbon (c1), the porous unit is enlarged, the wet film-forming property is deteriorated, and the compressibility increases. As for the carbon number of the hydrocarbon (c1), it is preferably in the range of 9 to 16, and more preferably in the range of 10 to 14, in order to achieve a higher level of both wet film-forming property and low compressibility.

[0018] The hydrocarbon (c1) has a carbon number within the specific range and contains only carbon atoms and hydrogen atoms, and examples thereof include normal paraffins, isoparaffins, aromatic compounds, cyclopentane acid compounds, etc. These compounds may be used alone or in combination of two or more. Among these, isoparaffins are preferred in terms of being able to achieve both wet film-forming properties and low compressibility at a higher level.

[0019] The density of the hydrocarbon (c1) at 15° C. is preferably 0.7 g / cm 3~0.83g / cm 3 The range is more preferably 0.7 g / cm 3 ~0.8g / cm 3 range.

[0020] In the film-forming aid (C), other film-forming aids may be used in combination with the hydrocarbon (c1). The content of the hydrocarbon (c1) in the film-forming aid (C) is preferably 30% by mass or more, and more preferably 70% by mass or more, in order to achieve both wet film-forming properties and low compressibility at a higher level.

[0021] The content of the hydrocarbon (c1) is preferably in the range of 0.1 to 30 parts by mass, more preferably in the range of 1 to 25 parts by mass, based on 100 parts by mass of the urethane resin (A).

[0022] As the urethane resin (A) used in the present invention, for example, a reaction product of a polyol (a1) and a polyisocyanate (a2) can be used.

[0023] As the polyol (a1), for example, polyester polyol, polyether polyol, polycarbonate polyol, etc. These polyols may be used alone or in combination of two or more.

[0024] The number average molecular weight of the polyol (a1) is preferably in the range of 500 to 10,000, and more preferably in the range of 700 to 8,000, from the viewpoint of mechanical properties and flexibility of the porous body. The number average molecular weight of the polyol (a1) refers to a value measured by gel permeation chromatography (GPC).

[0025] The polyol (a1) may be used in combination with a chain extender (a1-1) having a number average molecular weight of less than 500, if necessary. Examples of the chain extender (a1-1) include a chain extender having a hydroxyl group and a chain extender having an amino group. These chain extenders (a1-1) may be used alone or in combination of two or more.

[0026] As the chain extender having a hydroxyl group, for example, aliphatic polyol compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, hexamethylene glycol, sucrose, methylene glycol, glycerol, and sorbitol; aromatic polyol compounds such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; water, etc. These chain extenders can be used alone or in combination of two or more.

[0027] As the chain extender having an amino group, for example, ethylenediamine, 1,2-propylenediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 4,4'-diphenylmethanediamine, 3,3'-dichloro-4,4'-diphenylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, hydrazine, diethylenetriamine, triethylenetetramine, etc. These chain extenders may be used alone or in combination of two or more.

[0028] As the polyisocyanate (a2), for example, aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, xylene diisocyanate, and tetramethylxylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; alicyclic polyisocyanates such as cyclohexane diisocyanate, hydrogenated xylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate, etc. can be used. These polyisocyanates can be used alone or in combination of two or more.

[0029] As a method for producing the urethane resin (A), for example, there can be mentioned a method of producing by adding the polyol (a1), the polyisocyanate (a2) and, if necessary, the chain extender (a1-1) and reacting them. These reactions are preferably carried out at a temperature of 50° C. to 100° C. for about 3 hours to 10 hours. In addition, the reaction can also be carried out in a solvent (B) described later.

[0030] The molar ratio of the total of the hydroxyl group of the polyol (a1) and the hydroxyl group and amino group of the chain extender (a1-1) to the isocyanate group of the polyisocyanate (a2) [(hydroxyl group and amino group) / (isocyanate group)] is preferably in the range of 0.8 to 1.2, and more preferably in the range of 0.9 to 1.1.

[0031] The weight average molecular weight of the urethane resin (A) obtained by the above method is preferably in the range of 5,000 to 1,000,000, and more preferably in the range of 10,000 to 500,000, from the viewpoint of mechanical strength and flexibility of the porous body. The weight average molecular weight of the urethane resin (A) refers to a value measured in the same manner as the number average molecular weight of the polyol (a1).

[0032] As content of the said urethane resin (A), the range of 10 mass parts - 90 mass parts in a urethane resin composition is mentioned, for example.

[0033] As the solvent (B), for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N,N,2-trimethylpropionamide, N,N-dimethylacrylamide, N,N-dimethylpropionamide, N,N-diethylacetamide, N,N-diethylacrylamide, N-ethylpyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, etc. can be used. These organic solvents can be used alone or in combination of two or more. In addition, as needed, organic solvents such as ethyl acetate, methyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol can also be used in combination.

[0034] As content of the said solvent (B), the range of 10 mass % - 90 mass % in a urethane resin composition is mentioned, for example.

[0035] The urethane resin composition contains the urethane resin (A), the solvent (B), and the film-forming aid (C) as essential components, but may contain other additives as necessary.

[0036] As the other additives, for example, pigments, flame retardants, plasticizers, softeners, stabilizers, waxes, defoamers, dispersants, penetrants, surfactants, fillers, mildew inhibitors, antibacterial agents, ultraviolet absorbers, antioxidants, weathering stabilizers, fluorescent whitening agents, anti-aging agents, tackifiers, etc. can be used. These additives can be used alone or in combination of two or more.

[0037] Next, a method for producing a porous body by a wet film-forming method using the urethane resin composition will be described.

[0038] The wet film-forming method is a method of coating or impregnating a substrate surface with the urethane resin composition, and then bringing water or water vapor into contact with the coated or impregnated surface to solidify the urethane resin (A) to produce a porous body.

[0039] As the substrate to which the urethane resin composition is applied, for example, a substrate including nonwoven fabric, woven fabric, knitted fabric, resin film, etc. As the material constituting the substrate, for example, chemical fibers such as polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, polylactic acid fiber, etc., cotton, linen, silk, wool, and blended fibers thereof, etc. can be used.

[0040] The surface of the substrate may be subjected to treatments such as electroplating, mold release treatment, water repellency, water absorption, antibacterial and deodorizing, antibacterial, and ultraviolet shielding, as required.

[0041] As a method for coating or impregnating the surface of the substrate with the urethane resin composition, for example, gravure coating, knife coating, tube coating, and notch wheel coating can be cited. In this case, in order to adjust the viscosity of the urethane resin composition to improve coating workability, the amount of the organic solvent (B) used can be adjusted as needed.

[0042] The thickness of the coating film composed of the urethane resin composition applied or impregnated by the above method is preferably in the range of 0.5 mm to 5 mm, and more preferably in the range of 0.5 mm to 3 mm.

[0043] Examples of methods for bringing water or water vapor into contact with the coated surface formed by coating or impregnating the urethane resin composition include: immersing a substrate provided with a coating layer or an impregnation layer containing the urethane resin composition in a water bath; spraying water on the coated surface using a spray, etc. The immersion may be performed in a water bath at 5° C. to 60° C. for 2 to 20 minutes, for example.

[0044] The porous body obtained by the method is preferably washed with water at room temperature or warm water, the solvent (B) is extracted and removed, and then dried. The washing may be carried out, for example, with water at 5°C to 60°C for 20 minutes to 120 minutes, and the water used for washing is preferably replaced once or more, or continuously replaced with running water. The drying is preferably carried out, for example, with a dryer adjusted to 80°C to 120°C for 10 minutes to 60 minutes.

[0045] As described above, according to the present invention, by using a specific film-forming aid, a porous body with low compressibility and fine uniformity can be produced by a wet film-forming method. Therefore, the present invention is particularly suitable for the production of polishing pads, artificial leather, and synthetic leather.

[0046] [Example]

[0047] Hereinafter, the present invention will be described in more detail using examples.

[0048] [Synthesis Example 1] Synthesis of urethane resin (A-1)

[0049] In a reaction apparatus equipped with a stirrer, a reflux device, and a thermometer, 100 parts by mass of a polyester polyol (a reaction product of 1,4-butanediol and adipic acid, number average molecular weight: 2,000), 12 parts by mass of ethylene glycol, 519 parts by mass of N,N-dimethylformamide (hereinafter referred to as "DMF"), and 61 parts by mass of 4,4'-diphenylmethane diisocyanate were added, and the mixture was reacted at 60°C for 6 hours under stirring. Subsequently, 1 part by mass of isopropanol was added, and the mixture was stirred at 60°C for another hour to obtain a urethane resin (A-1) composition.

[0050] The obtained urethane resin (A-1) composition had a solid content of 25% by mass, a viscosity of 600 dPa, and a weight average molecular weight of the urethane resin of 188,100.

[0051] [Synthesis Example 2] Synthesis of urethane resin (A-2)

[0052] In a reaction apparatus equipped with a stirrer, a reflux device, and a thermometer, 65 parts by mass of polyester polyol (reaction product of ethylene glycol and adipic acid, number average molecular weight: 2,000), 35 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000), 20 parts by mass of 1,4-butanediol, 564 parts by mass of DMF, and 68 parts by mass of 4,4'-diphenylmethane diisocyanate were added, and the mixture was reacted at 60°C for 6 hours under stirring. Subsequently, 1 part by mass of isopropanol was added, and the mixture was further stirred at 60°C for 1 hour to obtain a urethane resin (A-2) composition.

[0053] The obtained urethane resin (A-2) composition had a solid content of 25% by mass, a viscosity of 550 dPa, and a weight average molecular weight of the urethane resin of 168,100.

[0054] [Method for measuring number average molecular weight and weight average molecular weight]

[0055] The number average molecular weight of the raw material polyol and the weight average molecular weight of the urethane resin (A) used in the synthesis examples represent values ​​measured by gel permeation chromatography (GPC) under the following conditions.

[0056] Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)

[0057] Column: The following columns manufactured by Tosoh Corporation were connected in series and used.

[0058] "TSKgel G5000" (7.8mm I.D. × 30cm) × 1 piece

[0059] "TSKgel G4000" (7.8mm I.D. × 30cm) × 1 piece

[0060] "TSKgel G3000" (7.8mm I.D. × 30cm) × 1 piece

[0061] "TSKgel G2000" (7.8mm I.D. × 30cm) × 1 piece

[0062] Detector: RI (differential refractometer)

[0063] Column temperature: 40℃

[0064] Eluent: Tetrahydrofuran (THF)

[0065] Flow rate: 1.0mL / min

[0066] Injection volume: 100 μL (sample concentration is 0.4 mass% tetrahydrofuran solution)

[0067] Standard sample: A calibration curve was prepared using the following standard polystyrene.

[0068] (Standard Polystyrene)

[0069] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

[0070] "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation

[0071] "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation

[0072] "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation

[0073] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0074] "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation

[0075] "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation

[0076] "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation

[0077] "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation

[0078] "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation

[0079] "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation

[0080] "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation

[0081] "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation

[0082] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0083] [Example 1]

[0084] To 100 parts by mass of the urethane resin (A-1) composition obtained in Synthesis Example 1, 40 parts by mass of DMF and an isoparaffin having 12 carbon atoms ("MERVEILLE 30" manufactured by East Asia Petroleum Co., Ltd., density: 0.77 g / cm) as a film-forming aid were added. 3 , hereinafter referred to as "c1-1") 1 part by mass is used to prepare a preparation liquid, which is applied to a polyethylene terephthalate (PET) film in a manner that the thickness (Wet) becomes 1 mm. Next, the coated substrate is immersed in a coagulation bath (water at 25°C) for 10 minutes to coagulate the urethane resin. Thereafter, the substrate is immersed in water at 50°C for 60 minutes to wash off the solvent. After washing, the substrate is dried with hot air at 100°C for 30 minutes to obtain a porous body.

[0085] [Example 2]

[0086] In Example 1, the type of film-forming aid was replaced by an isoparaffin having 12 carbon atoms (IP Solvent 1620 manufactured by Idemitsu Kosan Co., Ltd., density: 0.76 g / cm 3 , hereinafter referred to as "c1-2"), except that a porous body was obtained in the same manner as in Example 1.

[0087] [Example 3]

[0088] In Example 1, the type of film-forming aid was replaced by an isoparaffin having 12 carbon atoms (IP Clean LX manufactured by Idemitsu Kosan Co., Ltd., density: 0.74 g / cm 3 , hereinafter referred to as "c1-3"), except for this, a porous body was obtained in the same manner as in Example 1.

[0089] [Example 4]

[0090] In Example 1, the type of film-forming aid was replaced by an isoparaffin having 16 carbon atoms (IP Solvent 2028 manufactured by Idemitsu Kosan Co., Ltd., density: 0.79 g / cm 3 , hereinafter referred to as c1-4"), except that a porous body was obtained in the same manner as in Example 1.

[0091] [Example 5]

[0092] In Example 1, a porous body was obtained in the same manner as in Example 1 except that the urethane resin (A-2) composition was used instead of the urethane resin (A-1) composition.

[0093] [Comparative Example 1]

[0094] In Example 1, a porous body was obtained in the same manner as in Example 1 except that the type of the film-forming aid was changed to hexane (hereinafter referred to as "cR1-2").

[0095] [Comparative Example 2]

[0096] In Example 1, the type of film-forming aid was replaced by an isoparaffin having 20 carbon atoms (IP solvent 2835 manufactured by Idemitsu Kosan Co., Ltd., density: 0.82 g / cm 3 , hereinafter referred to as cR1-1"), except for this, a porous body was obtained in the same manner as in Example 1.

[0097] [Evaluation method of wet film-forming property]

[0098] The cross-sectional state of the porous body obtained in the example was observed using a scanning electron microscope "JSM-IT500" (magnification: 100 times) manufactured by JEOL Ltd. to confirm the unit shape (fineness, uniformity). If the units with a maximum lateral width of less than 70 μm accounted for 60% of the total, it was evaluated as "○", and the rest was evaluated as "×".

[0099] [Compression rate evaluation method]

[0100] The porous body obtained in the example was evaluated for compression rate according to Japanese Industrial Standards (JIS) L-1021-6. Specifically, the "thickness under standard pressure: t0" was measured after an initial load of 2 kPa was applied for 30 seconds, and then the "thickness under constant pressure: t1" was measured after a final load of 98 kPa was applied for 30 seconds, and the compression rate was calculated by applying the following formula.

[0101] Compression ratio (%) = 100 × (t0-t1) / t0

[0102] If the compression rate thus obtained was 20% or less, it was evaluated as "○", and other cases were evaluated as "×".

[0103] [Table 1]

[0104]

[0105] It is found that the porous body obtained using the urethane resin composition of the present invention has fine and uniform cells and is also excellent in low compressibility.

[0106] On the other hand, in Comparative Example 1, a hydrocarbon having a carbon number lower than that specified in the present invention was used as a film-forming aid, and porous cell formation was poor, and low compressibility was also poor.

[0107] Comparative Example 2 is a form in which a hydrocarbon having a carbon number exceeding that specified in the present invention is used as a film-forming aid, and porous cell formation is poor, and low compressibility is also poor.

Claims

1. A urethane resin composition comprising a urethane resin (A), a solvent (B) and a film-forming aid (C), characterized in that: The film-forming aid (C) contains a hydrocarbon (c1) having a carbon number of 8 to 18, In the urethane resin composition, the content of the solvent (B) is in the range of 10% by mass to 90% by mass, and the solvent (B) is an organic solvent. The urethane resin composition is used for wet film formation to produce a porous body.

2. The urethane resin composition according to claim 1, wherein The content of the hydrocarbon (c1) is in the range of 0.1 to 30 parts by mass relative to 100 parts by mass of the urethane resin (A).

3. The urethane resin composition according to claim 1 or 2, wherein The hydrocarbon (c1) is an isoparaffin.

4. A method for producing a porous body, characterized in that: The urethane resin composition according to any one of claims 1 to 3 is subjected to wet film formation.

Images