Aqueous urethane resin composition, and method for producing an aqueous urethane resin composition

Abstract

The present invention provides an aqueous urethane resin composition having excellent emulsifying and hot-melting properties, and a method for producing the aqueous urethane resin composition. [Solution] An aqueous urethane resin composition containing a urethane resin (A), an aqueous medium (B), and a surfactant (C) is used, characterized in that the urethane resin (A) is made from essential raw materials a polyol compound (a1) containing a diol (a1-1) having a polyoxyethylene group in its side chain and a monool (a1-2) having a polyoxyethylene group, and a polyisocyanate compound (a2) containing diphenylmethane diisocyanate.

Description

Technical Field

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[0001] The present invention relates to an aqueous urethane resin composition and a method for producing the aqueous urethane resin composition.

Background Art

[0002] Urethane resin compositions mainly include solvent-based urethane resin compositions and are used, for example, in applications such as artificial leather, synthetic leather, coating agents, glove coatings and glove films, and adhesives. Dimethylformamide (DMF) is often used in this solvent-based urethane resin composition. Since DMF is a concern for its adverse effects on living organisms and the environment and legal regulations are becoming stricter year by year, environmental countermeasures for products such as weak solvation, water systemization, and solvent-freeization are required (for example, see Patent Document 1).

[0003] Therefore, since the volatile organic substances can be reduced compared to the conventional solvent-based urethane resin composition, the development of an aqueous urethane resin composition (hereinafter sometimes referred to as "PUD") in which a urethane resin is dispersed in water for the above various applications has been studied.

[0004] When producing PUD, for the purpose of easily mixing, emulsifying and dispersing a urethane prepolymer having an NCO group with reaction activity, it is diluted and made low-viscosity with a solvent such as acetone or MEK, and after emulsifying and dispersing, it is distilled so that the solvent used in the production is substantially absent. However, there are problems in the production process such as (1) the cost due to the production time and energy required for the distillation process, and (2) the waste liquid treatment of the solvent used in the production process. Furthermore, there are problems in terms of performance that the polymer of the obtained PUD has a lower molecular weight than the conventional solvent-based urethane resin composition and is inferior in physical properties such as hot melt properties.

[0005] Therefore, materials having excellent emulsifying properties and hot melt properties have been demanded.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-119749 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide an aqueous urethane resin composition having excellent emulsifying and hot-melting properties, and a method for producing the aqueous urethane resin composition. [Means for solving the problem]

[0008] The inventors of the present invention conducted diligent research to solve the above problems and found that the above problems can be solved by using an aqueous urethane resin composition containing a specific urethane resin and an aqueous medium, thereby completing the present invention.

[0009] In other words, the present invention relates to an aqueous urethane resin composition containing a urethane resin (A), an aqueous medium (B), and a surfactant (C), wherein the urethane resin (A) is characterized in that it uses a polyol compound (a1) containing a diol (a1-1) having a polyoxyethylene group in its side chain and a monool (a1-2) having a polyoxyethylene group, and a polyisocyanate compound (a2) containing diphenylmethane diisocyanate as essential raw materials, and to a method for producing the aqueous urethane resin composition.

[0010] The present invention provides the following embodiments. [1] An aqueous urethane resin composition comprising a urethane resin (A), an aqueous medium (B), and a surfactant (C), wherein the urethane resin (A) is characterized in that it is made from essential raw materials a polyol compound (a1) comprising a diol (a1-1) having a polyoxyethylene group in its side chain and a monool (a1-2) having a polyoxyethylene group, and a polyisocyanate compound (a2) containing diphenylmethane diisocyanate. [2] The aqueous urethane resin composition according to [1], wherein the total amount of the diol (a1-1) used is in the range of 5 to 15% by mass in the raw materials of the urethane resin (A). [3] The aqueous urethane resin composition according to [1] or [2], wherein the total amount of the diols (a1-2) used is in the range of 0.5 to 4% by mass in the raw materials of the urethane resin (A). [4] The aqueous resin composition according to any one of [1] to [3], wherein the mass ratio of the diol (a1-1) to the diol (a1-2) [(a1-1) / (a1-2)] is in the range of 50 / 50 to 95 / 5. [5] The aqueous urethane resin composition according to any one of [1] to [4], wherein the amount of diphenylmethane diisocyanate used is in the range of 20 to 35% by mass in the raw materials of the urethane resin (A). [6] The aqueous urethane resin composition according to any one of [1] to [5], wherein the flow initiation temperature of the urethane resin (A) is in the range of 70 to 140°C. [7] A method for producing an aqueous urethane resin composition according to any one of [1] to [6], wherein the urethane resin (A) is obtained by reacting raw materials containing the polyol compound (a1) and the polyisocyanate compound (a2) under solvent-free conditions. [8] A method for producing an aqueous urethane resin composition according to any one of [1] to [6] above, wherein the urethane resin (A), the aqueous medium (B), and the surfactant (C) are emulsified and mixed without solvent under high temperature (in the range of 80 to 170°C) and high pressure (in the range of 0.1 to 0.4 MPa) conditions. [Effects of the Invention]

[0011] The aqueous urethane resin composition of the present invention has excellent emulsifying and hot-melting properties, and can therefore be used as a coating agent or adhesive, and is particularly suitable for use in the adhesive layer and surface layer of synthetic leather. [Modes for carrying out the invention]

[0012] The aqueous urethane resin composition of the present invention is characterized by containing a urethane resin (A), an aqueous medium (B), and a surfactant (C).

[0013] The aforementioned urethane resin (A) is made up of a polyol compound (a1) and a polyisocyanate compound (a2) as essential raw materials.

[0014] The polyol compound (a1) must be a diol (a1-1) having a polyoxyethylene group in its side chain, or a monool (a1-2) having a polyoxyethylene group.

[0015] Examples of the diol (a1-1) having a polyoxyethylene group in the side chain include compounds represented by the following general formula (1).

[0016] [ka]

[0017] [In general formula (1), n ​​represents an integer between 10 and 40.]

[0018] Furthermore, examples of diols (a1-1) having a polyoxyethylene group in the side chain include glycols having a methoxypolyethylene glycol chain (hereinafter sometimes referred to as a "methoxyPEG chain") in the side chain. Commercially available examples include "Ymer N90," "Ymer N120," and "Ymer N180" from Perstorp, and "TEGOMER D3403" from Evonik. These diols (a1-1) can be used alone or in combination of two or more. Among these, diols with a molecular weight in the range of 600 to 1200 are preferred because they yield an aqueous urethane resin composition with excellent emulsifying and hot-melting properties.

[0019] As the usage amount of the diol (a1-1), since an aqueous urethane resin composition having excellent emulsifying property and hot melt property can be obtained, the range of 5 to 15% by mass in the raw materials of the urethane resin (A) is preferable, and the range of 7 to 12% by mass is more preferable.

[0020] Examples of the monool (a1-2) having a polyoxyethylene group include polyoxyethylene-monomethyl ether, etc. Commercially available products include "Unionox M" manufactured by NOF Corporation, "Methoxy-PEG" manufactured by Toho Chemical Industry Co., Ltd., "Carbowax MPEG" manufactured by DOW, etc. These diols (a1-2) can be used alone or in combination of two or more. Among these, since an aqueous urethane resin composition having excellent emulsifying property and hot melt property can be obtained, those having a molecular weight in the range of 500 to 2000 are preferable.

[0021] As the usage amount of the diol (a1-2), since an aqueous urethane resin composition having excellent emulsifying property and hot melt property can be obtained, the total thereof is preferably in the range of 0.5 to 4% by mass in the raw materials of the urethane resin (A), and more preferably in the range of 1 to 3% by mass.

[0022] The mass ratio [(a1-1) / (a1-2)] of the diol (a1-1) and the diol (a1-2) is preferably in the range of 50 / 50 to 95 / 5, and more preferably in the range of 70 / 30 to 90 / 10, since an aqueous urethane resin composition having excellent emulsifying property and hot melt property can be obtained.

[0023] In addition, as the polyol compound (a1), if necessary, polyols other than the diol (a1-1) and the diol (a1-2) (hereinafter abbreviated as "other polyol compounds") can be used together.

[0024] Examples of the other polyol compounds mentioned above include polyether polyols, polyester polyols, polyacrylic polyols, polycarbonate polyols, and polybutadiene polyols. These other polyol compounds can be used individually or in combination of two or more. Among these, polyether polyols, polyester polyols, and polycarbonate polyols are preferred because they yield aqueous urethane resin compositions with excellent emulsifying and hot-melting properties.

[0025] Diphenylmethane diisocyanate is used as the polyisocyanate compound (a2).

[0026] The amount of diphenylmethane diisocyanate used is preferably in the range of 20 to 35% by mass, and more preferably in the range of 25 to 30% by mass, in the raw materials of the urethane resin (A), since an aqueous urethane resin composition with excellent emulsifying and hot-melting properties can be obtained.

[0027] Furthermore, as the polyisocyanate compound (a2), other polyisocyanate compounds (hereinafter abbreviated as "other polyisocyanate compounds") may be used in combination as needed.

[0028] Examples of the other polyisocyanate compounds include aromatic polyisocyanate compounds such as phenylene diisocyanate, toluene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide diphenylmethane polyisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dimer acid diisocyanate, and norbornene diisocyanate; and alicyclic diisocyanates such as norbornane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. These other polyisocyanate compounds can be used individually or in combination of two or more.

[0029] The weight-average molecular weight of the urethane resin (A) is preferably in the range of 30,000 to 200,000, and more preferably in the range of 40,000 to 100,000, in order to obtain an aqueous urethane resin composition having excellent emulsifying and hot-melting properties. In this invention, the weight-average molecular weight (Mw) is the value measured by gel permeation chromatography (GPC).

[0030] The flow initiation temperature (hereinafter sometimes referred to as "FP") of the urethane resin (A) is preferably in the range of 60 to 140°C, and more preferably in the range of 80 to 120°C, in order to obtain an aqueous urethane resin composition with excellent emulsifying and hot-melting properties.

[0031] As for the urethane resin (A), in addition to the polyol compound (a1) and the polyisocyanate compound (a2), a chain extender without an amino group may be used as needed. In particular, it is preferable to use a chain extender having a hydroxyl group, as this yields an aqueous urethane resin composition with excellent emulsifying and hot-melting properties.

[0032] Examples of the hydroxyl-containing chain extenders include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, sorbitol, bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, and trimethylolpropane. These chain extenders can be used alone or in combination of two or more. Among these, it is preferable to use an aliphatic polyol compound because it yields an aqueous urethane resin composition with excellent emulsifying and hot-melting properties.

[0033] The method for producing the urethane resin (A) is not particularly limited and can be any method. For example, it may be produced by a method in which all of the reaction materials containing the polyol compound (a1) and the polyisocyanate compound (a2) are reacted at once (one-shot method), or by a method in which the reaction materials are reacted sequentially. These reactions are preferably carried out at a temperature of 50 to 100°C for 3 to 10 hours.

[0034] The molar ratio [(isocyanate groups) / (hydroxyl groups)] between the total number of moles of hydroxyl groups in the polyol (a1) and the chain extender and the number of moles of isocyanate groups in the aromatic polyisocyanate (a2) is preferably in the range of 0.90 to 1.00, and more preferably in the range of 0.94 to 0.98.

[0035] Furthermore, while organic solvents can be used when producing the urethane resin (A), a method of reacting raw materials containing the polyol compound (a1) and the polyisocyanate compound (a2) under solvent-free conditions is preferred.

[0036] Examples of the organic solvents that can be used include ketone compounds such as acetone and methyl ethyl ketone; ether compounds such as tetrahydrofuran and dioxane; acetic acid ester compounds such as ethyl acetate and butyl acetate; nitrile compounds such as acetonitrile; and amide compounds such as dimethylformamide and N-methylpyrrolidone. These organic solvents may be used individually or in combination of two or more. It is preferable that the organic solvents be removed by distillation or the like when obtaining the aqueous urethane resin composition.

[0037] Examples of the aqueous medium (B) include ion-exchanged water and distilled water. These aqueous mediums can be used individually or in combination of two or more.

[0038] Examples of the surfactant (C) include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrylphenyl ether, polyoxyethylene sorbitol tetraoleate, and polyethylene-polypropylene copolymer; anionic emulsifiers such as fatty acid salts such as sodium oleate, alkyl sulfate salts, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, sodium alkanesulfonate salts, and sodium alkyldiphenyl ethersulfonate salts; and cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts. These emulsifiers can be used alone or in combination of two or more. Among these, anionic emulsifiers are preferred because they yield aqueous urethane resin compositions with excellent emulsifying and hot-melting properties.

[0039] The amount of surfactant (C) used is preferably in the range of 0.5 to 8 parts by mass, more preferably in the range of 0.5 to 5 parts by mass, and particularly preferably in the range of 1 to 4 parts by mass, per 100 parts by mass of urethane resin (A), in order to obtain an aqueous urethane resin composition having excellent emulsifying and hot-melting properties.

[0040] The method for producing the aqueous urethane resin composition of the present invention is not particularly limited and may be any method. For example, one method is to mix the urethane resin (A), the aqueous medium (B), and the surfactant (C).

[0041] Methods for mixing the urethane resin (A), the aqueous medium (B), and the surfactant (C) include, for example, a reaction vessel equipped with stirring blades; a kneader such as a kneader, continuous kneader, tapered roll, single-screw extruder, twin-screw extruder, tri-screw extruder, universal mixer, Plastmill, Bodeta type kneader; a rotary dispersion mixer such as a homomixer, static mixer, Filmix, Ebara Milder, Creamix, Ultra Turlux, Cavitron, Biomix; an ultrasonic dispersion device; and an in-line mixer or other device that has no moving parts and can mix by the flow of the fluid itself.

[0042] The mixing and kneading of the urethane resin (A), the aqueous medium (B), and the surfactant (C) is preferably carried out in multiple steps, as this yields an aqueous urethane resin composition with excellent emulsifying and hot-melting properties. Specifically, in the first step, it is preferable to knead the urethane resin (A), a portion of the aqueous medium (B), and the surfactant (C) to exceed the emulsification phase inversion point (i.e., from a W / O (Water in Oil) type to an O / W (Oil in Water) type), and in the next step, it is preferable to dilute and knead using the remaining aqueous medium (B). The mass ratio of the urethane resin (A) to the aqueous medium (B) [(B) / (A)] in the first step is preferably in the range of 0.1 to 0.7, and more preferably in the range of 0.2 to 0.5.

[0043] The mixing temperature of the urethane resin (A), the aqueous medium (B), and the surfactant (C) is preferably 80 to 170°C, as this yields an aqueous urethane resin composition with excellent emulsifying and hot-melting properties. In particular, the mixing temperature in the first stage (the stage where the emulsification phase inversion point is exceeded) is preferably 10 to 30°C higher than the FP of the urethane resin (A). At temperatures lower than FP + 10°C, the viscosity of the urethane resin (A) is high and mixing is difficult. On the other hand, at temperatures higher than FP + 30°C, the viscosity of the urethane resin (A) is low and unsuitable for mixing. In addition, emulsification becomes difficult, which is undesirable.

[0044] The viscosity of the urethane resin (A) during mixing and kneading is preferably in the range of 500 to 50,000 Pa·s, and more preferably in the range of 1,000 to 20,000 Pa·s, in order to obtain an aqueous urethane resin composition with excellent emulsifying and hot-melting properties.

[0045] The mixing of the urethane resin (A), the aqueous medium (B), and the surfactant (C) is preferably carried out by emulsification under high temperature and high pressure conditions without the use of solvents. In this invention, "high temperature" refers to a range of 80 to 170°C, and "high pressure" refers to a range of 0.1 to 0.4 MPa.

[0046] The aqueous urethane resin composition of the present invention may also contain other additives as needed.

[0047] Examples of the aforementioned other additives include thickeners, urethane catalysts, fillers, pigments, dyes, flame retardants, leveling agents, and anti-blocking agents. These additives can be used individually or in combination of two or more. When manufacturing the urethane resin (A), it is preferable that it is substantially free of organic solvents, but organic solvents may be added as additives.

[0048] Examples of the aforementioned thickening agents include association-type and acid-based thickening agents.

[0049] Examples of the urethane catalyst include organotin-based and bismuth-based catalysts.

[0050] Examples of the filler include calcium carbonate and silica.

[0051] Examples of the aforementioned pigments include carbon black.

[0052] Examples of the aforementioned dyes include azo dyes.

[0053] Examples of the aforementioned flame retardants include phosphorus-based flame retardants.

[0054] Examples of the leveling agent include silicon-based leveling agents.

[0055] Examples of the aforementioned blocking inhibitors include acrylics, cellulose esters, and the like.

[0056] The aqueous urethane resin composition of the present invention has excellent emulsifying and hot-melting properties, making it suitable for use in adhesive layers and surface layers of synthetic leather.

[0057] The synthetic leather in question comprises at least a base fabric (i), an adhesive layer (ii), and a surface layer (iii), wherein either or both of the adhesive layer (ii) and the surface layer (iii) are formed from the aqueous urethane resin composition of the present invention.

[0058] Examples of the synthetic leather of the present invention include the following configurations (1) to (4).

[0059] Synthetic leather (1): base fabric (i), adhesive layer (ii), skin layer (iii) Synthetic leather (2): base fabric (i), adhesive layer (ii), intermediate layer, skin layer (iii) Synthetic leather (3): base fabric (i), porous layer, adhesive layer (ii), skin layer (iii) Synthetic leather (4): base fabric (i), porous layer, adhesive layer (ii), intermediate layer, skin layer (iii)

[0060] Examples of the base fabric (i) include nonwoven fabrics, woven fabrics, knitted fabrics, etc., made from polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, linen, silk, wool, fiberglass, carbon fibers, and blends thereof.

[0061] The adhesive layer (ii) may be formed from the aqueous urethane resin composition of the present invention, or from a known material for forming the adhesive layer (ii) (hereinafter sometimes referred to as "resin for forming adhesive layer").

[0062] Examples of the adhesive layer-forming resin include known aqueous urethane resins, solvent-based urethane resins, solvent-free urethane resins, aqueous acrylic resins, silicone resins, polypropylene resins, polyester resins, and the like. These materials can be used individually or in combination of two or more.

[0063] The thickness of the adhesive layer (ii) can be, for example, in the range of 30 to 60 μm.

[0064] The aforementioned surface layer (iii) may be formed from the aqueous urethane resin composition of the present invention, or a known material for forming the aforementioned surface layer (iii) (hereinafter sometimes referred to as "surface layer forming resin") may include, for example, known aqueous urethane resins, solvent-based urethane resins, solvent-free urethane resins, aqueous acrylic resins, silicone resins, polypropylene resins, polyester resins, vinyl chloride resins, and the like. Furthermore, the aqueous urethane resin composition of the present invention can also be post-crosslinked with an isocyanate crosslinking agent. These materials can be used individually or in combination of two or more.

[0065] As the porous layer, one can use a solvent-based urethane resin composition formed by a known wet film-forming method; a water-based urethane resin composition that has been porousd by a known method; or a solvent-free urethane resin composition that has been foamed by a known method.

[0066] Examples of materials that form the intermediate layer include known water-based urethane resins, solvent-based urethane resins, solvent-free urethane resins, water-based acrylic resins, silicone resins, polypropylene resins, polyester resins, and vinyl chloride resins. These materials can be used individually or in combination of two or more.

[0067] The method for manufacturing the synthetic leather is not particularly limited, and it may be manufactured by any method. For example, one method (1) involves applying a resin for forming a surface layer to a release-treated substrate, drying it, and then applying the aqueous urethane resin composition of the present invention onto this surface layer (iii), drying it, and forming an adhesive layer (ii), which is then bonded to a base fabric (i). Another method (2) involves applying a resin for forming a surface layer to a release-treated substrate, drying it, and then applying the aqueous urethane resin composition of the present invention onto this surface layer (iii), bonding it to a base fabric (i), and then drying it to form an adhesive layer (ii).

[0068] Methods for applying the surface layer forming resin and the aqueous urethane resin composition include, for example, methods using an applicator, roll coater, spray coater, T-die coater, knife coater, comma coater, etc.

[0069] After manufacturing the synthetic leather, it can be aged for 1 to 10 days at, for example, 30 to 100 degrees Celsius, if necessary. [Examples]

[0070] The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples listed below.

[0071] (Synthesis Example 1: Synthesis of Urethane Resin (1)) A polyol compound was prepared by mixing 969 parts by mass of a polyester polyol (number average molecular weight: 1,000) consisting of 1,4-butanediol and adipic acid, 75 parts by mass of a diol having polyoxyethylene groups in its side chains (Perstorp's "YmerN120", number average molecular weight: 1,000), 15 parts by mass of a monool having polyoxyethylene groups (NOF Corporation's "Uniox M550", number average molecular weight: 550), 15 parts by mass of a monool having polyoxyethylene groups (NOF Corporation's "Uniox M2000", number average molecular weight: 2,000), and 381 parts by mass of the short-chain glycol 1,4-butanediol in a 2L disposable cup, and then temperature-controlled to 80°C. Meanwhile, 381 parts by mass of 4,4'-diphenylmethane diisocyanate, a diisocyanate warmed to 70°C, was added to a polyol compound in a 2L disposable cup and stirred to initiate the urethane reaction (one-shot bulk polymerization) ([NCO] / [OH] ratio = 0.98). After thorough stirring, the two-component mixture (polyol compound + diisocyanate) was poured into a mold release agent-treated vat. Furthermore, to complete the urethane reaction, a heat curing treatment (120°C × 16 hours) was performed to obtain urethane resin (1). Note that the polyol and monool raw materials used in this synthesis example were pre-dehydrated, and raw materials with a moisture content of 200 ppm or less were used.

[0072] (Synthesis Examples 2-25: Preparation of Urethane Resins (2)-(25)) According to Tables 1 and 2 below, urethane resins (2) to (25) were obtained in the same manner as in Synthesis Example 1. Note that the tables show the blending amounts per 100 parts by mass in total, and the actual blending amount was 15 times the values ​​shown in the tables.

[0073] [Table 1]

[0074] [Table 2]

[0075] In Tables 1 and 2, "1,4BG / AA #2000" refers to a polyester polyol (number average molecular weight: 2000) composed of 1,4-butanediol and adipic acid.

[0076] In Tables 1 and 2, "1,4BG / AA #1000" refers to a polyester polyol (number average molecular weight: 1000) composed of 1,4-butanediol and adipic acid.

[0077] In Tables 1 and 2, "1,4BG / AA #600" refers to a polyester polyol (number average molecular weight: 600) composed of 1,4-butanediol and adipic acid.

[0078] In Tables 1 and 2, "1,6HG_PCD #2000" refers to a polycarbonate polyol (number-average molecular weight: 2000) composed of 1,6-hexanediol and alkyl carbonate.

[0079] In Tables 1 and 2, "1,6HG_PCD #1000" refers to a polycarbonate polyol (number-average molecular weight: 1000) composed of 1,6-hexanediol and alkyl carbonate.

[0080] In Tables 1 and 2, "PEG #1000" refers to polyethylene glycol (number-average molecular weight: 1000).

[0081] In Tables 1 and 2, "YmerN120" refers to a diol with a methoxyPEG chain in its side chain (number-average molecular weight: 1000, manufactured by Perstorp).

[0082] In Tables 1 and 2, "D3403" refers to a diol with a methoxyPEG chain in its side chain (number-average molecular weight: 1200, manufactured by Evonik).

[0083] In Tables 1 and 2, "M550" refers to a monool containing a polyoxyethylene group (number average molecular weight: 550, manufactured by NOF Corporation).

[0084] In Tables 1 and 2, "M1000" refers to a monool containing a polyoxyethylene group (number average molecular weight: 1000, manufactured by NOF Corporation).

[0085] In Tables 1 and 2, "M2000" refers to a monool containing a polyoxyethylene group (number average molecular weight: 2000, manufactured by NOF Corporation).

[0086] In Tables 1 and 2, "1,4BG" refers to 1,4-butanediol.

[0087] In Tables 1 and 2, "MDI" refers to 4,4'-diphenylmethane diisocyanate.

[0088] (Example 1: Preparation of aqueous urethane resin composition (1)) The urethane resin (1) obtained in Synthesis Example 1 was pulverized to form flakes. 30 parts by mass of the flakes, 3.4 parts by mass of a 35% by mass aqueous solution of alkylnaphthalene sulfonate sodium (Perex NBL, manufactured by Kao Corporation) as a surfactant, and 9.8 parts by mass of water were placed in a metal pressure vessel (Portable Reactor TPR1-VS2-120, manufactured by Pressure Glass Industry Co., Ltd.) equipped with a pressure gauge, stirring mechanism, and temperature control mechanism, and the lid was closed. The target temperature was set to 130°C, and heating was started. Stirring (800 rpm) was started at 100°C, 30°C before the target temperature, and the temperature was held at 130°C for 15 minutes. After that, the container was immediately air-cooled to below 40°C. Stirring was continued until the temperature was below 40°C. The target temperature was set between the urethane resin's flow initiation temperature + 10 to 30°C.

[0089] Next, the emulsion was removed from the pressure container, and water was added to it in a mortar to obtain an aqueous urethane resin composition (1) with a urethane resin content of 25% by mass.

[0090] (Examples 2-15: Preparation of aqueous urethane resin compositions (2)-(15)) Aqueous urethane resin compositions (2) to (15) were obtained in the same manner as in Example 1, except that the urethane resin (1) and emulsifier used in Example 1 were changed to those shown in Tables 3 and 4.

[0091] (Comparative Examples 1-14: Preparation of aqueous urethane resin compositions (R1)-(R14)) Aqueous urethane resin compositions (R1) to (R14) were obtained in the same manner as in Example 1, except that the urethane resin (1) and emulsifier used in Example 1 were changed to those shown in Tables 5 and 6.

[0092] The aqueous urethane resin compositions (1) to (15) and (R1) to (R14) obtained in the above examples and comparative examples were evaluated as follows.

[0093] [Method for evaluating emulsification properties] The aqueous urethane resin compositions obtained in the above examples and comparative examples were transferred to glass bottles and evaluated visually according to the following criteria.

[0094] ◎: Milky white homogeneous liquid, no sediment. ○: Milky white homogeneous liquid with some sediment present (disperses with shaking). △: Water / solid urethane separated state + some milky white liquid ×: Mostly water / urethane separated state ××: Completely unable to emulsify

[0095] [Method for evaluating hot melt properties] In this invention, the hot-melt properties were evaluated based on the flow initiation temperature and molecular weight of the urethane resin according to the following criteria.

[0096] ○: The flow initiation temperature (FP) was in the range of 70-120°C, and the molecular weight (Mw) was 40,000 or more. △: The FP was in the range of 70-120°C and the molecular weight (Mw) was less than 40,000, or the FP was outside the range of 70-120°C and the molecular weight (Mw) was 40,000 or more. ×: The fission product (FP) was outside the 70-120°C range, and the molecular weight (Mw) was less than 40,000.

[0097] In this invention, the flow initiation temperature (FP) and molecular weight (Mw) were measured by the following measurement method.

[0098] <Flow start temperature> Sixty parts by mass of the aqueous urethane resin compositions obtained in the examples and comparative examples were taken into 500 ml disposable cups and heated (4 hours in a 40°C oven + 4 hours in a 60°C reduced-pressure oven) to evaporate the water and obtain solid urethane resin. The flow initiation temperature of the obtained solid urethane resin was measured using a constant test force extrusion type capillary rheometer "flow tester". Measurement conditions; Die: 1mmφ × 1mmL; Load: 98N; Measurement temperature: 40℃, hold for 10 minutes, then start; 3℃ / min

[0099] <Molecular weight (Mw)> Sixty parts by mass of the aqueous urethane resin compositions obtained in the examples and comparative examples were taken into 500 ml disposable cups and heated (4 hours in a 40°C oven + 4 hours in a 60°C reduced-pressure oven) to evaporate the water and obtain solid urethane resin. Next, the obtained solid urethane resin was dissolved in DMF and the molecular weight (Mw) was measured by gel permeation chromatography (GPC). Measurement conditions; Solvent: 10mM LiBr DMF Soln; Flow rate: 0.6 mL / min; Column: TSKgel-SuperAWM-H*2; Sample concentration: 4 mg / mL; Injection volume: 30 μL; Detector: RI

[0100] The evaluation results for the aqueous urethane resin compositions (1) to (15) and (R1) to (R14) obtained in the above examples and comparative examples are shown in Tables 2 and 3.

[0101] [Table 3]

[0102] [Table 4]

[0103] [Table 5]

[0104] [Table 6]

[0105] In Tables 3-6, "NV(%)" indicates the value of the non-volatile content (dry weight / pre-dry weight) containing the active ingredient of the surfactant.

[0106] In Tables 3-6, "TOP pressure" indicates the measured value (maximum value) from a pressure gauge equipped with a metal pressure vessel.

[0107] In Tables 3-6, "NBL" refers to an aqueous solution of sodium alkylnaphthalene sulfonate (active ingredient: 35%, "Perex NBL" manufactured by Kao Corporation).

[0108] In Table 4, "S-20F" refers to an aqueous solution of linear alkylbenzene sulfonate sodium (active ingredient: 20%, "Neogen S-20F" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0109] In Table 4, "L-64" refers to polyoxyethylene-polyoxypropylene condensate (100% active ingredient), manufactured by ADEKA Corporation as "Pluronic® L-64".

[0110] In Tables 5 and 6, "-" indicates that measurement was not possible because sufficient emulsification was not achieved and an aqueous urethane resin composition could not be obtained.

Claims

1. An aqueous urethane resin composition containing a urethane resin (A), an aqueous medium (B), and a surfactant (C), The aqueous urethane resin composition is characterized in that the urethane resin (A) is made from a polyol compound (a1) containing a diol (a1-1) having a polyoxyethylene group in its side chain and a monool (a1-2) having a polyoxyethylene group, and a polyisocyanate compound (a2) containing diphenylmethane diisocyanate as essential raw materials.

2. The aqueous urethane resin composition according to claim 1, wherein the total amount of the diol (a1-1) used is in the range of 5 to 15% by mass in the raw materials of the urethane resin (A).

3. The aqueous urethane resin composition according to claim 1, wherein the total amount of the diols (a1-2) used is in the range of 0.5 to 4% by mass in the raw materials of the urethane resin (A).

4. The aqueous resin composition according to claim 1, wherein the mass ratio [(a1-1) / (a1-2)] of the diol (a1-1) to the diol (a1-2) is in the range of 50 / 50 to 95 / 5.

5. The aqueous urethane resin composition according to claim 1, wherein the amount of diphenylmethane diisocyanate used is in the range of 20 to 35% by mass in the raw materials of the urethane resin (A).

6. The aqueous urethane resin composition according to claim 1, wherein the flow initiation temperature of the urethane resin (A) is in the range of 70 to 140°C.

7. A method for producing an aqueous urethane resin composition according to any one of claims 1 to 6, wherein the urethane resin (A) is obtained by reacting raw materials containing the polyol compound (a1) and the polyisocyanate compound (a2) under solvent-free conditions.

8. A method for producing an aqueous urethane resin composition according to any one of claims 1 to 6, wherein the urethane resin (A), the aqueous medium (B), and the surfactant (C) are emulsified and mixed under solvent-free conditions at high temperature (in the range of 80 to 170°C) and high pressure (in the range of 0.1 to 0.4 MPa).

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