Aqueous resin composition, and aqueous surface treatment agent and article using said aqueous resin composition

Abstract

To provide an aqueous resin composition which can enhance efficiency of coating by allowing evaluation of coating quality to be efficiently performed and can improve coating quality.SOLUTION: The aqueous resin composition contains an aqueous polyurethane (A), a matting agent (B), and an additive (C). The aqueous resin composition has a shear viscosity at a temperature of 30°C and a shear rate of 1,000 s-1 in the range of 0.3 Pa s or more and 3.0 Pa s or less. The aqueous resin composition has a Trouton's ratio (=elongational viscosity / shear viscosity) in the range of 3.0 or more and 8.0 or less, which is a ratio of the elongational viscosity at a temperature of 30°C and an elongation rate of 3,000 s-1 to the shear viscosity at a temperature of 30°C and a shear rate of 3,000 s-1.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous resin composition, and an aqueous surface treatment agent and article using the aqueous resin composition. [Background technology]

[0002] Synthetic leathers, such as polyurethane leather, PVC leather, and TPO (thermoplastic olefin) leather, are used in a variety of fields, including clothing, bags, shoes, and industrial materials, as substitutes for natural leather or as leather materials with better durability than natural leather. Synthetic leathers used in industrial materials, such as vehicle interiors and interior materials, are particularly required to be durable and abrasion-resistant. Various efforts are being made to meet these requirements.

[0003] For example, there are methods in which the surface layer is formed from a silicone-modified polycarbonate polyurethane resin, and methods in which a finishing agent containing an aqueous polyurethane resin, a crosslinking agent, a silicone compound, and a filler is applied to the surface of the leather. These methods are said to be able to improve abrasion resistance by reducing the coefficient of friction of the polyurethane resin layer that forms the surface of the synthetic leather.

[0004] In recent years, from the perspective of environmental issues, there has been a desire to replace conventional solvent-based coating agents with water-based coating agents for industrial products. However, water-based materials tend to have inferior coating quality compared to solvent-based materials due to the influence of wettability and viscosity. In particular, in gravure coating, a significant difference was observed in surface smoothness when comparing water-based and solvent-based materials.

[0005] As a conventional aqueous material, for example, a water-based matte coating agent has been disclosed in which 50 to 300 parts by weight of fine particles of at least one crosslinked, spherical organic resin selected from acrylic resin, urethane resin, urea resin, silicone resin, epoxy resin, melamine resin, polypropylene resin, polyethylene resin, nylon resin, and fluororesin, with an average particle size of 0.1 to 3.0 μm, are blended with 100 parts by weight of the solid content of the water-based polyurethane resin (Patent Document 1).

[0006] Another conventional aqueous material proposed is an aqueous resin composition containing an aqueous polyurethane (A) obtained by reacting a polyol (a1) with a polyisocyanate (a2), an acid-modified non-chlorinated polyolefin (B), a matting agent (C), and a crosslinking agent (D), wherein the mass ratio of the aqueous polyurethane (A) to the acid-modified non-chlorinated polyolefin (B) [(A) / (B)] is in the range of 55 / 45 to 98 / 2 (Patent Document 2).

[0007] Furthermore, in order to improve wettability, which affects coating quality, an example has been proposed in which a nonionic surfactant is used as a component of an aqueous surface treatment agent for synthetic leather (Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-262248 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-084400 [Patent Document 3] Patent No. 6207304 Summary of the Invention [Problem to be solved by the invention]

[0009] However, none of the above Patent Documents 1 to 3 discloses any adjustment of the viscosity of the aqueous resin composition, and there is a limit to how much the coating quality of the aqueous resin composition can be improved. Obtaining the appropriate viscosity for an aqueous resin composition requires adjusting the type and amount of viscosity modifier (thickener) while checking the surface condition after coating using an actual gravure coater, which reduces the efficiency of optimizing coatability. Specifically, coating tests must be conducted repeatedly using samples of the aqueous resin composition designed to a viscosity close to that of a paint with confirmed coatability (measured using a Brookfield viscometer or Zahn cup viscometer), and the viscosity must be adjusted based on the results to achieve good coating quality. For this reason, the aqueous resin composition must be provided to the coating manufacturer, who must then conduct prototypes using the actual machine and provide feedback on the results, requiring the customer's cooperation. Furthermore, adjusting the viscosity during prototype testing on the actual machine is extremely cumbersome and requires long testing times, resulting in inefficiency. Furthermore, similar testing is required every time the formulation is changed or the coating equipment is changed, resulting in time-consuming improvements.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aqueous resin composition that enables efficient evaluation of coating quality to increase the efficiency of coating optimization and improve coating quality, as well as an aqueous surface treatment agent and article that use the aqueous resin composition. [Means for solving the problem]

[0011]

[0003] As a result of extensive research, the present inventors have found that by adjusting the shear viscosity and Trouton ratio of the aqueous resin composition as a blend to fall within a predetermined range, viscosity adjustment during coating trials, as is required for blends designed according to conventional viscosity standards, is unnecessary or almost unnecessary, reducing the number of trials, enabling efficient evaluation of coating quality, and speeding up product development by improving the efficiency of coatability optimization. Furthermore, while conventional blends require viscosity adjustment during coating, which can result in fluctuations in quality due to viscosity adjusters, water, etc., the present invention has found that, because viscosity adjustment during coating is unnecessary, good coating quality can be stably obtained.

[0012] That is, the present invention provides the following configurations. [1] An aqueous resin composition containing an aqueous polyurethane (A), a matting agent (B), and an additive (C), Temperature: 30°C, shear rate: 1000 s -1 the shear viscosity of the aqueous resin composition is in the range of 0.3 Pa s or more and 3.0 Pa s or less, Temperature 30℃, shear rate 3000 s -1 Shear viscosity and elongation rate at 3000 s -1 The aqueous resin composition has a Trouton ratio (=extensional viscosity / shear viscosity) of 3.0 or more and 8.0 or less, which is the ratio of the extensional viscosity in the aqueous resin composition to the extensional viscosity in the aqueous resin composition.

[0013] [2] The aqueous resin composition according to [1] above, wherein the shear viscosity is 0.3 Pa·s or more and 1.0 Pa·s or less.

[0014] [3] The aqueous resin composition according to [1] above, wherein the extensional viscosity is 1.0 Pa·s or more and 10.0 Pa·s or less.

[0015] [4] The aqueous resin composition according to any one of [1] to [3] above, wherein the content of the aqueous polyurethane (A) is 3.0% by mass or more and 50.0% by mass or less when the total amount of the aqueous resin composition is 100% by mass.

[0016] [5] The aqueous resin composition according to any one of the above [1] to [4], wherein the additive (C) includes a viscosity adjuster of a nonionic surfactant.

[0017] [6] An aqueous surface treatment agent containing the aqueous resin composition according to any one of [1] to [5] above.

[0018] [7] An article having a coating film of the aqueous resin composition according to any one of [1] to [5] above. [Effects of the Invention]

[0019] According to the present invention, it is possible to efficiently evaluate coating quality, thereby increasing the efficiency of coating optimization and improving coating quality. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail.

[0021] [Aqueous resin composition] The aqueous resin composition of the present invention is an aqueous resin composition containing an aqueous polyurethane (A), a matting agent (B) and an additive (C), and is sintered at a temperature of 30°C and a shear rate of 1000 s -1 The shear viscosity of the aqueous resin composition at a shear rate of 3000 s (1 / sec) is 0.3 Pa s or more and 3.0 Pa s or less, and the shear viscosity is 0.3 Pa s or more and 3.0 Pa s or less at a temperature of 30°C and a shear rate of 3000 s -1 Shear viscosity and elongation rate at 3000 s -1 The Trouton ratio (= extensional viscosity / shear viscosity) of the aqueous resin composition, which is the ratio of the extensional viscosity in the aqueous resin composition to the extensional viscosity in the aqueous resin composition, is in the range of 3.0 or more and 8.0 or less.

[0022] [Shear viscosity of aqueous resin composition] In this embodiment, the temperature is 30°C and the shear rate is 1000 s -1 The shear viscosity of the aqueous resin composition is 0.3 Pa·s or more and 3.0 Pa·s or less, preferably 0.3 Pa·s or more and 1.0 Pa·s or less, and more preferably 0.3 Pa·s or more and 0.5 Pa·s or less. When the shear viscosity of the aqueous resin composition is within the range of 0.3 Pa·s or more and 3.0 Pa·s or less, the viscosity of the aqueous resin composition tends to be appropriate when a predetermined shear force is applied, making it easier to obtain good coating quality without adjusting the viscosity with a viscosity modifier or the like during coating, and improving coating efficiency. In addition, low viscosity can be achieved during coating at high shear rates, such as with roll or gravure machines, improving coating quality.

[0023] [Trouton ratio of aqueous resin composition] In this embodiment, the "Trouton ratio" refers to the ratio at a temperature of 30°C and a shear rate of 3000 s -1 Shear viscosity at a temperature of 30°C and an elongation rate of 3000 s -1 is the ratio of the extensional viscosity to the shear viscosity (extensional viscosity / shear viscosity). In this embodiment, the Trouton ratio of the aqueous resin composition under the above conditions is 3.0 or more and 8.0 or less, preferably 3.5 or more and 7.5 or less, and more preferably 3.5 or more and 5.5 or less. When the Trouton ratio of the aqueous resin composition is within the range of 3.0 or more and 8.0 or less, the fluidity of the aqueous resin composition can be maintained, the spreadability of the aqueous resin composition can be improved, and the coating efficiency can be improved. In particular, when the aqueous resin composition is applied, it can exhibit viscosity that makes it easy to apply using a roll coater or gravure roll coater.

[0024] The Trouton ratio of the aqueous resin composition can be controlled by adjusting the ratio of the low-viscosity material to the high-viscosity material contained in the aqueous resin composition to adjust the extensional viscosity and / or shear viscosity. For example, the Trouton ratio of the aqueous resin composition can be controlled by adjusting the blending ratio of the aqueous polyurethane in the aqueous resin composition to adjust the extensional viscosity and / or shear viscosity. Alternatively, the Trouton ratio can be controlled by adjusting the ratio of the low-viscosity material to the high-viscosity material contained in the materials used in the aqueous polyurethane (A) (such as the polyol (a1) and the polyisocyanate (a2)) to adjust the extensional viscosity and / or shear viscosity.

[0025] Those skilled in the art can grasp the viscosity of the aqueous polyurethane (A) used in the aqueous resin composition. Furthermore, by appropriately adjusting the compounding ratio of the aqueous polyurethane (A) in the aqueous resin composition, those skilled in the art can obtain an aqueous resin composition having a shear viscosity and Trouton ratio within the desired ranges based on known techniques within the scope of ordinary experimentation. Similarly, those skilled in the art can obtain the shear viscosity and Trouton ratio of the aqueous polyurethane (A), which is the reaction product of the polyol (a1) and the polyisocyanate (a2), by adjusting the types and compounding ratios of the polyol (a1) and the polyisocyanate (a2).

[0026] (Water-based polyurethane (A)) The aqueous polyurethane (A) is a compound obtained by reacting a polyol (a1) with a polyisocyanate (a2). The aqueous polyurethane (A) is preferably a compound obtained by reacting a compound (a-1) having an active hydrogen group, a compound (a-2) having at least one active hydrogen group and a hydrophilic group, and a compound (a-3) having an isocyanate group.

[0027] When the total amount of the aqueous resin composition is taken as 100% by mass, the content of the aqueous polyurethane (A) is preferably 3.0% by mass or more and 50.0% by mass or less, more preferably 4.0% by mass or more and 30.0% by mass or less, and even more preferably 5.0% by mass or more and 20.0% by mass or less. The content of the aqueous polyurethane (A) is expressed as a value calculated as a solid content relative to the total amount of the aqueous resin composition. When the content of the aqueous polyurethane (A) is 3.0% by mass or more and 50.0% by mass or less, an aqueous resin composition suitable as an aqueous coating agent used in gravure coating, etc., can be obtained.

[0028] The aqueous polyurethane (A) is preferably one obtained by reacting a compound (a-1) having an active hydrogen group, a compound (a-2) having at least one active hydrogen group and a hydrophilic group, and a compound (a-3) having an isocyanate group.

[0029] Examples of the active hydrogen group contained in the compound (a-1) include a hydroxyl group, a phenolic hydroxyl group, an amino group, and a mercapto group. Among these, a hydroxyl group, a carboxyl group, and an amino group are preferred. Furthermore, the compound (a-1) preferably has two or more of these active hydrogen groups per molecule.

[0030] Examples of the compound (a-1) include relatively low molecular weight polyols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone and alkylene oxide adducts thereof, glycerin, trimethylolethane, trimethylolpropane, sorbitol, and pentaerythritol.

[0031] Further, examples of the compound (a-1) other than those mentioned above include polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, polyesteramide polyols, polythioether polyols, polyolefin polyols, polyamines, etc. These compounds (a-1) can be used alone or in combination of two or more.

[0032] The polyester polyol can be obtained by a dehydration condensation reaction of a diol compound, a dicarboxylic acid compound, a hydroxycarboxylic acid compound, or the like, a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, or copolymerization of the polyester obtained by these reactions. Examples of diol compounds used as raw materials for the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone, and alkylene oxide adducts thereof.

[0033] Examples of dicarboxylic acid compounds that can be used as raw materials for the polyester polyol include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid.

[0034] Furthermore, examples of the hydroxycarboxylic acid compound that serves as a raw material for the polyester polyol include p-hydroxybenzoic acid and p-(2-hydroxyethoxy)benzoic acid.

[0035] Examples of the polyether polyol include those obtained by addition polymerization of a compound having two or more active hydrogen groups, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, sorbitol, sucrose, aconite sugar, femimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, or 1,2,3-propanetrithiol, with a cyclic ether compound, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, or cyclophenexylene; and those obtained by ring-opening polymerization of the cyclic ether compound using a cationic catalyst, a protonic acid, a Lewis acid, or the like as a catalyst.

[0036] The polycarbonate polyol can be obtained by reacting a diol compound such as 1,4-butanediol, 1,6-hexanediol, or diethylene glycol with diphenyl carbonate and phosgene.

[0037] Examples of the polyamine include ethylenediamine, 1,6-hexamethylenediamine, piperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, 1,2-propanediamine, diethylenetriamine, triethylenetetramine, and hydrazine.

[0038] The compound (a-2) is a compound having at least one active hydrogen group and a hydrophilic group, and examples of the compound (a-2) having at least one of the active hydrogen groups and the hydrophilic group include compounds having a carboxyl group, a sulfonic acid group and its salt, and a nonionic hydrophilic group having an alkylene oxide repeating unit. These compounds (a-2) can be used alone or in combination of two or more.

[0039] Examples of the compound having a carboxyl group as the hydrophilic group include compounds having a carboxyl group and a hydroxyl group or an amino group, or dicarboxylic acid compounds, such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dioxymaleic acid, 2,6-dioxybenzoic acid, 3,4-diaminobenzoic acid, succinic acid, adipic acid, maleic acid, phthalic acid, alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, and histidine.

[0040] Examples of the compound having a sulfonic acid group as the hydrophilic group include compounds having a sulfonic acid group and a hydroxyl group, a carboxyl group, or an amino group, or disulfonic acid compounds, such as 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfoisophthalic acid, sulfanilic acid, 1,3-phenylenediamine-4,6-disulfonic acid, and 2,4-diaminotoluene-5-sulfonic acid.

[0041] Furthermore, examples of compounds having a nonionic hydrophilic group as the hydrophilic group include polyethylene glycol, polypropylene glycol, copolymers of ethylene oxide and propylene oxide, copolymers of ethylene oxide and polybutylene oxide, and copolymers of ethylene oxide and other alkylene oxides.

[0042] Examples of the compound (a-3) having an isocyanate group include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2-diphenylmethane diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, 3,3-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, and 1,5-tetrahydronaphthalene diisocyanate. Examples of polyisocyanates include hexane diisocyanate, tetramethylene diisocyanate, 1,6-hexanemethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclophenethylene diisocyanate, 1,4-cyclophenethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and 3,3-dimethyl-4,4-dicyclohexylmethane diisocyanate. These compounds containing an isocyanate group can be used alone or in combination of two or more.

[0043] Among the compounds (a-3) having an isocyanate group, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate are preferred because they can reduce raw material costs, and 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and 4,4-dicyclohexylmethane diisocyanate are preferred because they can improve light resistance and heat resistance.

[0044] Examples of a method for producing the aqueous polyurethane (A) by reacting the polyol (a1) with the polyisocyanate (a2) include a method in which, in the absence of a solvent or in the presence of an organic solvent, a compound (a-1) having an active hydrogen group, a compound (a-2) having at least one active hydrogen group and a hydrophilic group, and a compound (a-3) having an isocyanate group are added and mixed in an appropriate order, and reacted at a reaction temperature in the range of about 25°C to 150°C.

[0045] The reaction between the polyol (a1) and the polyisocyanate (a2) is preferably carried out in such a manner that the equivalent ratio of the isocyanate groups of the polyisocyanate (a2) to the hydroxyl groups of the polyol (a1) is in the range of 0.8 to 2.5, and more preferably in the range of 0.9 to 1.5.

[0046] In the aqueous polyurethane (A), when the compound (a-2) having at least one active hydrogen group and a hydrophilic group has an acid group such as a carboxy group or a sulfonic acid group as the hydrophilic group, it is preferable that the acid group be neutralized. Neutralization can be carried out by adding a basic compound to the reaction mixture after the reaction of the polyol (a1) with the polyisocyanate (a2). Representative examples of the neutralizing basic compound include tertiary amines such as trimethylamine, triethylamine, and tri-n-butylamine; and inorganic basic substances such as lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium chloride, and potassium chloride.

[0047] When producing the aqueous polyurethane (A), a chain extender can be used as needed. Examples of the chain extender include polyamines, hydrazine compounds, and other compounds having active hydrogen atoms. These chain extenders can be used alone or in combination of two or more. Among these, the aqueous polyurethane (A) obtained by hydrazine elongation using a hydrazine compound is particularly preferred because it has improved adhesion to plastic substrates.

[0048] Examples of the polyamine include diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine, diethylenetriamine, dipropylenetriamine, and triethylenetetramine. Among these, ethylenediamine is preferred.

[0049] Examples of the hydrazine compound include hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine, succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, β-semicarbazidopropionic acid hydrazide, 3-semicarbazido-propyl-carbazic acid ester, semicarbazido-3-semicarbazidomethyl-3,5,5-trimethylcyclohexane, etc. Among these, hydrazine is preferred.

[0050] Examples of the other compounds having active hydrogen include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, and sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; and water.

[0051] When a polyamine is used as the chain extender, the equivalent ratio of the amino group to the isocyanate group in the polyamine [amino group / isocyanate group] is preferably 1.2 or less, and more preferably in the range of 0.3 to 1.

[0052] Examples of organic solvents that can be used when producing the aqueous polyurethane (A) include ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as tetrahydrofuran and dioxane, acetate solvents such as ethyl acetate and butyl acetate, nitrile solvents such as acetonitrile, and amide solvents such as dimethylformamide and N-methylpyrrolidone. These organic solvents can be used alone or in combination of two or more.

[0053] In order to ensure safety and reduce the burden on the environment, the organic solvent may be partially or completely removed during or after the production of the aqueous polyurethane (A), for example, by distillation under reduced pressure.

[0054] The aqueous polyurethane (A) obtained by the above method preferably has a mass average molecular weight in the range of 5,000 to 500,000, more preferably in the range of 5,000 to 200,000, and even more preferably in the range of 20,000 to 100,000, because it can exhibit durability. In the present invention, the measurement of the mass average molecular weight (in terms of polystyrene) by GPC (gel permeation chromatography) was carried out using an HLC8220 system manufactured by Tosoh Corporation under the following conditions. Separation column: Four TSKgel GMHHR-N columns manufactured by Tosoh Corporation Column temperature: 40℃ Mobile phase: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0ml / min Sample concentration: 0.4% by mass Sample injection volume: 100 microliters Detector: differential refractometer

[0055] When the weight average molecular weight is 5,000 or more, not only is durability improved but problems due to insufficient drying tend to be less likely to occur, and when the molecular weight is 500,000 or less, problems such as reduced coatability are less likely to occur, which is preferable.

[0056] (Matting agent (B)) Examples of the matting agent (B) include silica particles, organic beads, calcium carbonate, magnesium carbonate, barium carbonate, talc, aluminum hydroxide, calcium sulfate, kaolin, mica, asbestos, mica, calcium silicate, and alumina silicate.

[0057] Examples of the silica particles include dry silica and wet silica. From the viewpoint of light resistance and abrasion resistance, wet silica such as gel silica can be used. From the viewpoint of a high scattering effect and a wide range of gloss adjustment, dry silica may be used. Furthermore, from the viewpoint of easy dispersion in the composition, dry silica whose surface is modified with an organic compound may be used. The average particle size of these silica particles is preferably in the range of 2 μm to 14 μm, more preferably in the range of 3 μm to 12 μm.

[0058] Examples of the organic beads include acrylic beads, urethane beads, silicon beads, and olefin beads.

[0059] The matting agent (B) may contain one or more of the above materials, for example, the matting agent (B) may contain wet silica and organic beads.

[0060] (Additive (C)) The aqueous resin composition of the present invention may contain an additive (C) in addition to the above-mentioned components. The additive (C) may be contained in the aqueous polyurethane (A) or the aqueous resin composition.

[0061] Examples of additive (C) include leveling agents, inorganic fine particles such as colloidal silica and alumina sol, polymethyl methacrylate-based organic fine particles, defoamers (foam breakers), anti-sagging agents, wetting and dispersing agents, viscosity modifiers, ultraviolet absorbers, metal deactivators, peroxide decomposers, flame retardants, reinforcing agents, plasticizers, lubricants, rust inhibitors, fluorescent brighteners, inorganic heat absorbers, flame retardants, antistatic agents, and dehydrating agents. Additive (C) may contain one or more of the above components. Furthermore, each of the above components constituting additive (C) may be composed of one or more materials.

[0062] When additive (C) contains a viscosity modifier, the content of the viscosity modifier is preferably in the range of 0.3% by mass to 3.5% by mass, more preferably in the range of 0.5% by mass to 2.0% by mass, and even more preferably in the range of 1.0% by mass to 1.8% by mass, when the total amount of the aqueous resin composition is taken as 100% by mass. The above content of the viscosity modifier is expressed as a value converted into solid content with respect to the total amount of the aqueous resin composition. If the content of the viscosity modifier is 0.3% by mass or less, it is difficult to obtain the desired viscoelastic properties. Furthermore, if it is 3.5% by mass or more, the coating film properties such as water resistance and light resistance of the coating composition will be reduced.

[0063] The viscosity adjuster is not particularly limited, but is preferably a nonionic surfactant such as a polymer-type special nonionic surfactant. The viscosity adjuster may contain one or more nonionic surfactants.

[0064] (Crosslinking agent (D)) The aqueous resin composition of the present invention may contain a crosslinking agent (D). The crosslinking agent (D) may be contained in the aqueous polyurethane (A) or the aqueous resin composition.

[0065] Examples of the crosslinking agent (D) include oxazoline, carbodiimide, polyisocyanate, blocked isocyanate, epoxy, polysiloxane, aziridine, urea resin-based crosslinking agents such as alkylated melamine, and hydrazide-based crosslinking agents. Of these, carbodiimide can be used from the standpoint of crosslinking performance and safety. The crosslinking agent (D) may contain one or more of the above components.

[0066] When the total amount of the aqueous resin composition is taken as 100% by mass, the content of the crosslinking agent (D) is preferably in the range of 0.2% by mass to 12.0% by mass, and more preferably in the range of 0.4% by mass to 8.0% by mass, from the viewpoint of coating film strength. The content of the crosslinking agent (D) is expressed as a value converted into solid content with respect to the total amount of the aqueous resin composition.

[0067] (Wax (E)) The aqueous resin composition of this embodiment may contain a wax (E) as needed.

[0068] The wax (E) is not particularly limited, but examples thereof include polyolefin waxes. Among polyolefin waxes, those having a melting range of 140 to 180°C are preferred, more preferably 145 to 175°C, and even more preferably 150 to 170°C, because they are less likely to leave traces (solvent traces) when solvents such as alcohol come into contact with the coating film, improving solvent resistance. Examples of such polyolefin waxes include polyethylene wax and polypropylene wax. The polyolefin wax may contain one or more of the above materials. When two or more polyolefin waxes are used in combination, the melting range of the mixture is the melting range of the mixture. The melting range is measured in accordance with JIS test method K0064-1992.

[0069] Among the above polyolefin waxes, those containing polypropylene wax as the main component are preferred because they can reduce solvent marks. Furthermore, the content of the polyolefin wax, when the total amount of the aqueous resin composition is taken as 100% by mass, is preferably in the range of 0.5% by mass to 10% by mass, more preferably in the range of 1.0% by mass to 8.0% by mass, from the viewpoint of reducing solvent marks and enhancing coating strength. The above content of the polyolefin wax is expressed as a value converted into solid content with respect to the entire aqueous resin composition.

[0070] (pigment) The aqueous resin composition of the present embodiment may contain a pigment in combination as needed. The pigment may be an additive contained in the aqueous polyurethane (A) or the aqueous resin composition.

[0071] The pigment is not particularly limited, and various types can be used, including, for example, organic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments, inorganic pigments, and plastic pigments, as listed in the 1970 edition of the Paint Raw Materials Handbook (compiled by the Japan Paint Manufacturers Association).

[0072] Examples of organic pigments include various insoluble azo pigments such as Benzidine Yellow, Hansa Yellow, and Lake 4R; soluble azo pigments such as Lake C, Carmine 6B, and Bordeaux 10; various (copper) phthalocyanine pigments such as Phthalocyanine Blue and Phthalocyanine Green; various chlorine dye lakes such as Rhodamine Lake and Methyl Violet Lake; various mordant dye pigments such as Quinoline Lake and Fast Sky Blue; various vat dye pigments such as Anthraquinone pigments, Thioindigo pigments, and Perinone pigments; various quinacridone pigments such as Synchasia Red B; various dioxazine pigments such as Dioxazine Violet; various condensed azo pigments such as Chromophtal; and aniline black.

[0073] Examples of inorganic pigments include various chromates such as yellow lead, zinc chromate, and molybdate orange; various ferrocyanide compounds such as iron blue; various metal oxides such as titanium oxide, zinc white, mapico yellow, iron oxide, red iron oxide, chrome oxide green, and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red, and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various silicates such as calcium silicate and ultramarine; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese purple; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, and brass powder; flake pigments of these metals, mica flake pigments; metallic pigments and pearl pigments such as mica flake pigments coated with metal oxides and micaceous iron oxide pigments; graphite, carbon black, and the like.

[0074] Examples of extender pigments include precipitated barium sulfate, powdered barium sulfate, precipitated calcium carbonate, calcium bicarbonate, kansui stone, alumina white, silica, hydrous fine powdered silica (white carbon), ultrafine powdered anhydrous silica (aerosil), silica sand, talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and yellow ochre. Examples of plastic pigments include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

[0075] As the pigment, it is more preferable to use inorganic oxides such as titanium oxide and zinc oxide as white pigments, and carbon black as black pigments, because they are excellent in durability, weather resistance, and designability.

[0076] The aqueous surface treatment agent according to this embodiment contains the above-mentioned aqueous resin composition. The aqueous surface treatment agent is typically used on the surface of an article, which will be described later.

[0077] The article according to this embodiment has a coating film of the aqueous resin composition of the present invention. Examples of such articles include housings for home appliances (refrigerators, washing machines, air conditioners, televisions, etc.), housings for electronic devices (personal computers, mobile phones, smartphones, etc.), materials for musical instruments (pianos, electones, electronic musical instruments, etc.), plastic molded articles such as interior materials for automobiles or railroad cars (instrument panels, door trim, headlinings, tonneau covers, etc.), building materials or furniture materials (wallpaper, decorative sheets for plywood, decorative sheets for steel plates, leather upholstery, etc.), and packaging materials (wrapping films, etc.), wood materials (plywood, laminated lumber, single-layer laminated materials, etc.), ceramic materials (interior tiles, bricks, etc.), materials for sports equipment (skiing, archery, golf, tennis, etc.), footwear materials (shoe uppers, soles, cores, heels, top lifts, insoles, etc.), and metal materials (iron, copper, zinc, aluminum, etc.). Among these articles, the aqueous resin composition of the present invention can be suitably used for plastic molded articles, and among the plastic molded articles, it is preferable to use it for TPO leather and TPO sheets. [Example]

[0078] The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the following examples. In the following examples, "parts" and "%" are by mass unless otherwise specified.

[0079] (Production Example 1) A four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube was charged with 500 parts by mass of 1,6-hexanediol-based polycarbonate diol (weight average molecular weight: 1,000), 34 parts by mass of 2,2-dimethylolpropionic acid, and 355 parts by mass of methyl ethyl ketone under a nitrogen stream and mixed uniformly. Next, 295 parts by mass of 4,4-dicyclohexylmethane diisocyanate was added, followed by 0.1 parts by mass of dibutyltin dilaurate. The mixture was reacted at 70°C for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer (NCO% in terms of solids: 3.8% by mass) having isocyanate groups at the molecular terminals. 25 parts by mass of triethylamine was added to the methyl ethyl ketone solution of the urethane prepolymer obtained above to neutralize the carboxyl groups in the urethane prepolymer, and then 1,555 parts by mass of ion-exchanged water was added. 23 parts by mass of ethylenediamine was then added and the reaction was allowed to proceed. After the reaction was completed, the methyl ethyl ketone was distilled off under reduced pressure to obtain aqueous polyurethane PUD-1 (non-volatile content: 35% by mass).

[0080] Example 1 Aqueous polyurethane PUD-1, propylene glycol, polysiloxane leveling agent (BYK, BYK-342), gel silica (Tosoh, NIPGEL AZ-200), cross-linked urethane beads (Negami Chemical Industrial Co., Ltd., Art Pearl C-800T), polymeric special nonionic surfactant (ADEKA, ADEKA NOL UH-420, active ingredient 30%), foam opener (SAN NOPCO, SN DEFOAMER 777), and water were blended in the proportions shown in Table 1 and mixed uniformly to obtain an aqueous resin composition.

[0081] Example 2 An aqueous resin composition was obtained in the same manner as in Example 1, except that the amount of the polymer-type special nonionic surfactant added was increased.

[0082] Example 3 An aqueous resin composition was obtained in the same manner as in Example 1, except that propylene glycol, a water-soluble solvent, was not used.

[0083] Example 4 An aqueous resin composition was obtained in the same manner as in Example 1, except that a different polymer-type special nonionic surfactant (ADEKA Corporation, ADEKA Nol UH-450VF, active ingredient 30%) was used and its amount was reduced.

[0084] Example 5 An aqueous resin composition was obtained in the same manner as in Example 4, except that a urethane-modified polyether viscosity modifier (San Nopco, Sn Thickener-612NC, active ingredient 45%) was used instead of the polymer-type special nonionic surfactant.

[0085] (Comparative example 1) An aqueous resin composition was obtained in the same manner as in Example 1, except that the amount of polymer-type special nonionic surfactant was reduced and the viscosity was reduced by heating at 50°C for 30 days.

[0086] (Comparative Example 2) An aqueous resin composition was obtained in the same manner as in Example 1, except that the amount of the polymer-type special nonionic surfactant was reduced.

[0087] (Comparative Example 3) An aqueous resin composition was obtained in the same manner as in Example 1, except that layered hectorite (LAPONITE (registered trademark) RD, manufactured by BYK, water content less than 10%) was used instead of the polymer-type special nonionic surfactant and the amount of layered hectorite added was reduced.

[0088] Comparative Example 4 An aqueous resin composition was obtained in the same manner as in Comparative Example 3, except that the amount of layered hectorite added was further reduced.

[0089] (Comparative Example 5) An aqueous resin composition was obtained in the same manner as in Comparative Example 4, except that an alkali-soluble thickener (Boncoat VE, manufactured by DIC Corporation, active ingredient content 29%) was used instead of layered hectorite.

[0090] The aqueous polyurethane and aqueous resin compositions used in Examples 1 to 5 and Comparative Examples 1 to 5 were measured and evaluated by the following methods.

[0091] (Measurement of shear viscosity and calculation of Trouton ratio) For Examples 1 to 5 and Comparative Examples 1 to 5, the following methods were used to measure the viscosity of the mixture at 30°C and a shear rate of 1000 s -1 Shear viscosity of water-based polyurethane at 30°C and elongation rate of 3000 s -1 The extensional viscosity of the aqueous polyurethane at 100°C and 150°C was measured, and the ratio (extensional viscosity / shear viscosity) was calculated as the Trouton ratio.

[0092] The extensional viscosity was measured in accordance with the capillary rheometer evaluation method described in JIS-7199 (ISO 11443, ASTM D 3835). Specifically, a twin capillary type apparatus (RHEOGRAPH20 manufactured by Gottfert) was used. Two capillary dies, one with a length of 10 mm and a diameter of 0.5 mm and the other with a length of 0.25 mm and a diameter of 0.5 mm, were used, and measurements of polyurethane dispersions (aqueous polyurethane) were carried out at a measurement temperature of 30°C.

[0093] and shear rate 300-300,000 s -1 The true shear viscosity of the polyurethane dispersion (waterborne polyurethane) was obtained by removing the pressure loss using the Burgley correction from the apparent shear viscosity (pressure) measured at . The extensional viscosity corresponding to the extensional rate was calculated using the Cogswell equation from the obtained true shear viscosity and pressure loss. -1 True shear viscosity and elongational velocity at 3000 s -1 The Trouton ratio (= extensional viscosity / shear rate) was calculated from the extensional viscosity. Temperature: 30°C, shear rate: 1000 s -1 Shear viscosity at 30°C and 3000 s -1 The values ​​of extensional viscosity and Trouton ratio at 1000 kJ / g are shown in Table 1.

[0094] For reference, the viscosities of the aqueous resin compositions of Examples 1 to 5 and Comparative Examples 1 to 5 were measured using a B-type viscometer (Toki Sangyo Co., Ltd., VISCOMETER TVB-22) at a rotation speed of 30 rpm with a No. 2 rotor at a temperature of 25°C. The values ​​are shown in Tables 1 and 2.

[0095] (Coatability) The aqueous resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were applied onto a TPO sheet (thickness 0.4 mm) using a gravure roll coater (#100 gravure plate, coating speed 10 m / min), and then dried at 120°C for 1 minute to obtain evaluation samples. In terms of coating appearance quality, a coating film with no or minimal irregularities was rated as good (◯); a coating film with oblique lines or orange peel texture visible depending on the viewing angle was rated as slightly poor (△); and a coating film with clearly visible oblique lines or orange peel texture was rated as poor (×).

[0096] The results of measurement and evaluation by the above methods are shown in Tables 1 and 2.

[0097] [Table 1]

[0098] [Table 2]

[0099] From the results in Table 1, in Example 1, the temperature was 30°C and the shear rate was 1000 s -1 It was found that when the shear viscosity of the polyurethane dispersant was 0.37 Pa·s and the Trouton ratio was 3.5, good coatability was obtained.

[0100] In Example 2, when the blending amount of polymer-type special nonionic surfactant was increased compared to Example 1, the temperature was 30°C and the shear rate was 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.46 Pa·s and the Trouton ratio was 5.3, indicating good coatability.

[0101] In Example 3, when propylene glycol was not used as a water-soluble solvent, the temperature was 30°C and the shear rate was 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.35 Pa·s and the Trouton ratio was 5.5, indicating good coatability.

[0102] In Example 4, when a polymer-type special nonionic surfactant different from that in Example 1 was used and its amount was reduced, the temperature was 30°C and the shear rate was 1000 s -1The shear viscosity of the polyurethane dispersant was 0.37 Pa·s and the Trouton ratio was 7.3, indicating good coatability.

[0103] In Example 5, when a urethane-modified polyether viscosity modifier was used instead of a polymer-type special nonionic surfactant, the viscosity was -1 The shear viscosity of the polyurethane dispersant was 0.35 Pa·s and the Trouton ratio was 4.1, indicating good coatability.

[0104] On the other hand, from the results of Table 2, in Comparative Example 1, when the amount of polymer-type special nonionic surfactant was reduced and the viscosity was reduced by heating at 50°C for 30 days, the viscosity was reduced by 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.24 Pa·s, indicating poor coatability.

[0105] In Comparative Example 2, when the amount of polymer-type special nonionic surfactant was reduced, the temperature was 30°C and the shear rate was 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.26 Pa·s, indicating that the coatability was somewhat poor.

[0106] In Comparative Example 3, when layered hectorite was used instead of the polymer-type special nonionic surfactant and the amount of the layered hectorite was reduced, the temperature was 30°C and the shear rate was 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.05 Pa·s, indicating poor coatability. In addition, the elongational viscosity and Trouton ratio could not be measured because the elongational hardening rate at which elongational hardening began was low and the dispersant hardened under elongation.

[0107] In Comparative Example 4, when the amount of layered hectorite was further reduced, the temperature was 30°C and the shear rate was 1000 s -1The shear viscosity of the polyurethane dispersant was 0.08 Pa·s, indicating poor coatability. In addition, the elongational viscosity and Trouton ratio could not be measured because the elongational hardening rate at which elongational hardening began was low and the dispersant hardened under elongation.

[0108] In Comparative Example 5, when an alkali-soluble thickener was used instead of layered hectorite, the viscosity was 1000 s at a temperature of 30°C and a shear rate of 1000 s -1 The shear viscosity of the polyurethane dispersant was 0.17 Pa·s and the Trouton ratio was 8.1, indicating poor coatability.

Claims

1. An aqueous resin composition containing an aqueous polyurethane (A), a matting agent (B), and an additive (C), and not containing a fluororesin, the matting agent (B) is one or more selected from the group consisting of silica particles, organic beads, calcium carbonate, magnesium carbonate, barium carbonate, talc, aluminum hydroxide, calcium sulfate, kaolin, mica, asbestos, mica, calcium silicate, and alumina silicate; the organic beads are one or more types selected from the group consisting of acrylic beads, urethane beads, silicon beads, and olefin beads; the additive (C) comprises a polysiloxane leveling agent and a viscosity modifier; The viscosity modifier is a nonionic surfactant, the content of the viscosity modifier is in the range of 1.149% by mass or more and 3.5% by mass or less, when the total amount of the aqueous resin composition is taken as 100% by mass, Temperature: 30°C, shear rate: 1000 s －１ the shear viscosity of the aqueous resin composition is in the range of 0.3 Pa s or more and 3.0 Pa s or less, Temperature 30°C, shear rate 3000 s －１ Shear viscosity and elongation rate at 3000 s －１ The aqueous resin composition has a Trouton ratio (=extensional viscosity / shear viscosity) of 3.0 or more and 8.0 or less, which is a ratio of extensional viscosities in the aqueous resin composition.

2. 2. The aqueous resin composition according to claim 1, wherein the shear viscosity is 0.3 Pa·s or more and 1.0 Pa·s or less.

3. 2. The aqueous resin composition according to claim 1, wherein the extensional viscosity is 1.0 Pa·s or more and 10.0 Pa·s or less.

4. 4. The aqueous resin composition according to claim 1, wherein the content of the aqueous polyurethane (A) is 3.0% by mass or more and 50.0% by mass or less, when the total amount of the aqueous resin composition is 100% by mass.

5. The aqueous resin composition according to any one of claims 1 to 3, further comprising propylene glycol.

6. An aqueous surface treatment agent comprising the aqueous resin composition according to any one of claims 1 to 5.

7. An article having a coating film of the aqueous resin composition according to any one of claims 1 to 5.

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