Aqueous urethane resin dispersion, coating material composition, and coating film thereof.

Abstract

The present invention provides an aqueous urethane resin dispersion composition that can form a coating film at low temperatures of 20 to 100°C and that has adhesion, hardness, and flexibility. [Solution] The aqueous polyurethane resin dispersion composition of the present invention is an aqueous polyurethane resin dispersion composition comprising a polyurethane resin and an aqueous medium, wherein the polyurethane resin has constituent units derived from polyester polyol (A) having polyol (Aa) and dicarboxylic acid (Ab) as constituent components, constituent units derived from polyether polyol (G) and constituent units derived from polyisocyanate (B), and has aromatic rings in the polyurethane resin, the content of aromatic rings in the polyurethane resin is 4% to 18% by mass, and the content of ether bonds is 0.5% to 10% by mass. The aqueous polyurethane resin dispersion of the present invention can contribute to the SDGs (Sustainable Development Goals).

Description

Technical Field

[0001] The present invention relates to an aqueous urethane resin dispersion.

Background Art

[0002] An aqueous polyurethane resin dispersion composition can obtain a coating film having adhesiveness, abrasion resistance, and rubbery properties, and can reduce volatile organic compounds compared with conventional solvent-based polyurethanes. Therefore, it is a material that is being increasingly replaced from solvent-based polyurethanes as an environmentally friendly material. An aqueous polyurethane resin dispersion composition is used, for example, as a fracture-resistant material used for an intermediate coat in the exterior of an automobile. When the aqueous polyurethane resin dispersion composition is used as a film, a paint or a coating material, or a fracture-resistant material, it is applied to a substrate or the like using a coating device such as a bar coater, a roll coater, an air spray, etc. A coating film is formed on the substrate by heating and drying the applied aqueous polyurethane resin dispersion composition.

[0003] It is known that a coating film obtained by applying an aqueous urethane resin dispersion using polycarbonate polyol as a raw material is excellent in light resistance, heat resistance, hydrolysis resistance, and oil resistance (see Patent Document 1).

[0004] On the other hand, a coating film obtained from an aqueous urethane resin dispersion using polyester polyol is known to be excellent in adhesion to various substrates (Patent Documents 2 to 4). Patent Document 2 describes that, as a polyol component, a mixture of two polyol components, for example, polyester polyol and polyether polyol, is used, and further a compound having at least one acid group and at least one group capable of reacting with an isocyanate group and an acid anhydride are used to obtain a hydroxy-functional polyester-polyurethane dispersion capable of obtaining a coating film with adjustable hardness, elasticity, and resistance.

[0005] Patent Document 3 describes an aqueous coating composition for pre-coating steel plates that includes a water-dispersible polyurethane resin using a polyester polyol having an aromatic ring structure with an aromatic ring structure content within a specific range, which forms a coating film with good solvent resistance, conformability, vegetation resistance, hardness, and substrate opacity. Patent Document 4 describes a urethane resin composition using an aromatic polyester polyol with an aromatic ring concentration within a specific range. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-120757 [Patent Document 2] Special Publication No. 2010-526921 [Patent Document 3] Japanese Patent Publication No. 2011-140561 [Patent Document 4] International Publication No. 2019 / 004349 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Although the polyurethane resin compositions using polyester polyols described in Patent Documents 2 to 4 have been shown to have high adhesion to various resins, sufficient adhesion could not be obtained in coating films dried at low temperatures (e.g., 80°C) for a short time (e.g., 10 minutes). Furthermore, in applications requiring fracture-resistant materials, conventional aqueous polyurethane resin dispersion compositions require a drying process at 140°C or higher because they contain a melamine crosslinking agent.

[0008] From the perspective of reducing greenhouse gas emissions, lowering the drying temperature from the conventional 140°C or higher to 20-100°C to create the coating film is expected to reduce energy costs and environmental impact. Furthermore, for applications requiring fracture resistance, the created coating film needs to have sufficient adhesion and hardness.

[0009] Therefore, the object of the present invention is to provide an aqueous urethane resin dispersion that can form a coating film by low-temperature drying at 20 to 100°C. Furthermore, it is also to provide an aqueous urethane resin dispersion that can be used in compositions that form a coating film having sufficient adhesion, hardness, and flexibility. [Means for solving the problem]

[0010] The inventors have discovered that by using a special polyester polyol, an aqueous urethane resin dispersion can be obtained that provides a highly hard coating film through low-temperature, short-time drying. In a preferred embodiment, they have also found that an aqueous urethane resin dispersion can be provided that provides a coating film with high elastic modulus, excellent adhesion to the substrate, and high fracture energy through low-temperature, short-time drying. By enabling low-temperature, short-time processing, it is possible to contribute to achieving SDGs (Sustainable Development Goals) Goal 7, etc.

[0011] The present invention is specifically as follows: [1] An aqueous polyurethane resin dispersion composition comprising a polyurethane resin and an aqueous medium, The polyurethane resin has constituent units derived from polyester polyol (A) composed of polyol (Aa) and dicarboxylic acid (Ab), constituent units derived from polyether polyol (G), and constituent units derived from polyisocyanate (B), and also has an aromatic ring in the polyurethane resin. An aqueous polyurethane resin dispersion composition having an aromatic ring content of 4% to 18% by mass and an ether bond content of 0.5% to 10% by mass in the polyurethane resin. [2] An aqueous polyurethane resin dispersion composition comprising two or more polyurethane resins and an aqueous medium, At least one polyurethane resin has constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), and constituent units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin. At least one polyurethane resin has constituent units derived from polyether polyol (G) and constituent units derived from polyisocyanate (B), An aqueous polyurethane resin dispersion composition in which the total polyurethane resin contains 4% to 18% by mass of aromatic rings and 0.5% to 10% by mass of ether bonds. [3] The aqueous polyurethane resin dispersion composition according to [1] or [2], wherein the polyurethane resin further comprises a constituent unit derived from an acidic group-containing polyol (C) and a constituent unit derived from a chain extender (E). [4] The aqueous polyurethane resin dispersion composition according to [1] or [2], wherein the dicarboxylic acid (Ab) comprises an aromatic dicarboxylic acid. [5] The aqueous polyurethane resin dispersion composition according to [1] or [2], having constituent units derived from a polyol (F) other than the polyester polyol (A), an acidic group-containing polyol, and a polyether polyol (G). [6] The aqueous polyurethane resin dispersion composition according to [4], wherein the two carboxyl groups in the aromatic dicarboxylic acid are in a para position on the benzene ring. [7] The aqueous polyurethane resin dispersion composition according to [5], wherein the polyol (F) is a polycarbonate polyol. [8] The aqueous polyurethane resin dispersion composition according to [4], wherein the polyether polyol (G) and the polyol (F) have 2 hydroxyl groups. [9] The aqueous polyurethane resin dispersion composition according to [3], wherein the chain extender (E) is a polyamine.

[10] The aqueous polyurethane resin dispersion composition according to [1], wherein the mass ratio of the polyester polyol (A) to the polyether polyol (G) is 50:50 to 90:10.

[11] The aqueous polyurethane resin dispersion composition according to [1] or [2], comprising 50 to 100% by mass of an alicyclic polyisocyanate in the total amount of the polyisocyanate (B).

[12] The aqueous polyurethane resin dispersion composition according to [1] or [2], wherein the weight-average molecular weight of the polyurethane resin is 100,000 or more.

[13] The aqueous polyurethane resin dispersion composition according to [1] or [2], wherein the hydroxyl value of the dicarboxylic acid (Ab) is 55 to 140 mg KOH / g. A coating material composition comprising the aqueous polyurethane resin dispersion composition described in

[14] [1] or [2]. A coating film obtained by applying and drying the coating material composition described in

[15]

[14] .

[16] The coating film according to

[15] , wherein when a grid-pattern peel test of the coating film obtained by drying the coating material composition at 80°C for 45 minutes is performed on the electrodeposited surface, no peeling is observed. A method for manufacturing a coating film, comprising the step of drying the coating material composition described in

[17]

[14] at 20°C to 100°C.

[18] The coating material composition according to

[14] for use as a primer or base coat for metal exteriors.

[19] The coating material composition according to

[14] for fracture-resistant materials. The coating material composition according to

[15] for floor coatings, plastic or rubber coatings, of the coating film according to

[20] and

[15] . A steel plate treatment agent containing the coating material composition described in

[21]

[14] .

[22] A polyurethane resin having constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), constituent units derived from a polyether polyol (G), and constituent units derived from a polyisocyanate (B), and having aromatic rings in the polyurethane resin, wherein the content of aromatic rings in the polyurethane resin is 4% to 18% by mass, and the content of ether bonds is 0.5% to 10% by mass. A coating film containing the polyurethane resin described in

[23] and

[22] .

[24] A polyurethane resin composition comprising two or more polyurethane resins, At least one polyurethane resin has structural units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab) and structural units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin. At least one polyurethane resin has structural units derived from a polyether polyol (G) and structural units derived from a polyisocyanate (B). A polyurethane resin composition in which the content of the aromatic ring is 4% to 18% by mass and the content of the ether bond is 0.5% to 10% by mass in all the polyurethane resins. A coating film containing the polyurethane resin composition according to

[25]

[24] .

Effect of the Invention

[0012] The composition containing the aqueous urethane resin dispersion of the present invention can form a coating film in low-temperature drying at 20 to 100°C. Further, the composition containing the aqueous urethane resin dispersion of the present invention forms a coating film having sufficient adhesion, hardness, and flexibility.

Mode for Carrying Out the Invention

[0013] [First Aspect of the Present Invention] The present invention is an aqueous polyurethane resin dispersion composition containing a polyurethane resin and an aqueous medium, where the polyurethane resin has structural units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), structural units derived from a polyether polyol (G), and structural units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin, An aqueous polyurethane resin dispersion composition in which the content of the aromatic ring in the polyurethane resin is 4% to 18% by mass and the content of the ether bond is 0.5% to 10% by mass.

[0014] Preferably, the polyurethane resin further comprises structural units derived from an acidic group-containing polyol (C), structural units derived from a chain extender (E), and structural units derived from a polyol (F) other than components (A), (G), and (C). Furthermore, it is preferable that the aqueous polyurethane resin dispersion is neutralized by the neutralizing agent (D).

[0015] In other words, in polyurethane resins, polyols (X) that react with polyisocyanate (B) to constitute the polyurethane resin include polyester polyols (A), polyether polyols (G), optionally acidic group-containing polyols (C), and optionally polyols (F). On the other hand, polyols (Aa) that react with dicarboxylic acid (Ab) to constitute polyester polyol (A) include optionally branched polyols (Aa1) and optionally linear polyols (Aa2). Furthermore, dicarboxylic acid (Ab) includes optionally aromatic dicarboxylic acid (Ab1) and optionally aliphatic dicarboxylic acid (Ab2).

[0016] In this specification, "substantially 100% by mass" means that it does not contain other components to such an extent that they alter the properties of the aqueous polyurethane resin dispersion composition or the functions and properties of the coating film obtained from the aqueous polyurethane resin dispersion composition, but it does not exclude the inclusion of other components to an extent that does not impair the functions or properties.

[0017] <Polyester polyol (A)> Polyester polyol (A) is a polyol obtained by reacting polyol (Aa) with dicarboxylic acid (Ab). Polyester polyol (A) can be obtained by a method similar to that of known polyester production methods, which involve dehydrating and condensing polyol (Aa) and dicarboxylic acid (Ab).

[0018] From the viewpoint of obtaining a coating film with high hardness through low-temperature, short-time drying, the polyester polyol (A) is preferably present in an amount of 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 80% by mass or more, of the total polyol (X) constituting the polyurethane resin. Within this range, a coating film with high elastic modulus can also be obtained through low-temperature, short-time drying. Furthermore, from the viewpoint of obtaining a coating film with high adhesion through low-temperature, short-time drying, the polyester polyol (A) is preferably present in an amount of 90% by mass or less, and more preferably 80% by mass or less, of the total polyol (X) constituting the polyurethane resin.

[0019] The polyester polyol (A) preferably has two hydroxyl groups. In other words, it is preferably a polyester diol. This is because the aqueous polyurethane resin dispersion composition can form a coating film with excellent hardness and adhesion without crosslinking, and therefore crosslinking is not necessarily required.

[0020] The acid value of polyester polyol (A) is preferably 0.01 to 5.0 mgKOH / g. Within this range, a polyurethane resin with particularly good physical properties can be obtained using it as a raw material. The acid value is more preferably 0.01 to 1.0 mgKOH / g, and even more preferably 0.01 to 0.5 mgKOH / g. By setting it within this range, the hardness of the coating film obtained by drying the aqueous urethane resin dispersion and the adhesion to the electrodeposited surface can be improved. In this specification, the acid value shall be the value measured in accordance with the indicator titration method of JIS K 1557.

[0021] The hydroxyl value of polyester polyol (A) is preferably 22.5 to 280 mg KOH / g, more preferably 35 to 225 mg KOH / g, even more preferably 55 to 140 mg KOH / g, and particularly preferably 55 to 125 mg KOH / g. Within this range, the hardness of the coating film obtained by drying the aqueous urethane resin dispersion and its adhesion to the electrodeposited surface can be improved. In this specification, the hydroxyl value shall be the value measured in accordance with Method B of JIS K 1557.

[0022] The number-average molecular weight Mn of polyester polyol (A) is preferably 400 to 5000. Within this range, fluidity (e.g., viscosity of 500 to 10000 cP) can be easily obtained under heating (e.g., 75°C), and it is easy to handle. The number-average molecular weight Mn is more preferably 500 to 3000, even more preferably 800 to 2000, and particularly preferably 900 to 2000. In this specification, the number-average molecular weight Mn is the number-average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K 1577. Specifically, the hydroxyl value is measured and calculated using the terminal group determination method, with the formula being (56.1 × 1000 × valency) / hydroxyl value (in this formula, the unit of hydroxyl value is [mgKOH / g]). In the above formula, the valency is the number of hydroxyl groups in one molecule.

[0023] The weight-average molecular weight Mw of the polyester polyol (A) is preferably 500 to 30000, and more preferably 1000 to 13000. In this specification, the weight-average molecular weight Mw is the value measured by GPC.

[0024] The dispersion degree Mw / Mn of the polyester polyol (A) is preferably 1.0 to 3.0, and more preferably 1.6 to 2.5.

[0025] <Polyol (Aa)> The polyol (Aa) used in this invention reacts with the dicarboxylic acid (Ab), described later, to form a polyester polyol (A).

[0026] Polyol (Aa) may consist solely of branched polyols (Aa1), or it may consist of branched polyols (Aa1) and straight polyols (Aa2).

[0027] The branched polyol (Aa1) refers to a polyol having a tertiary or quaternary carbon atom in one molecule. Examples include 1,2-propylene glycol, 1-methyl-1,3-butylene glycol, 2-methyl-1,3-butylene glycol, neopentyl glycol, 1-methyl-1,4-pentanediol, 2-methyl-1,4-pentanediol, 3-methyl-1,4-pentanediol, 1-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-dimethylbutylene glycol, 1,3-dimethylbutylene glycol, 2,3-dimethylbutylene glycol, and 1,4-dimethylbutylene glycol. However, from the viewpoint of improving the elastic modulus and adhesion of the resulting coating film, among these, a diol having a quaternary carbon atom is preferred, and neopentyl glycol is more preferred. Furthermore, the branched polyol preferably has 4 to 8 carbon atoms, and the branched chain represents a hydrocarbon group, preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an alkyl group having 1 to 2 carbon atoms. These branched polyols (Aa1) can be used alone or in combination of two or more types.

[0028] The content of branched-chain polyol (Aa1) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass, and particularly preferably substantially 100% by mass, based on the total amount of polyol (Aa).

[0029] As the linear polyol (Aa2), short-chain aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol can be used, with 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol being preferred. The content of the linear polyol (Aa2) is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably substantially 0% by mass, based on the total amount of polyol (Aa). These linear polyols (Aa2) can be used individually or in combination of two or more.

[0030] <Dicarboxylic acid (Ab)> The polyol (Aa) used in this invention reacts with a dicarboxylic acid (Ab) to form a polyester polyol (A).

[0031] The dicarboxylic acid (Ab) preferably contains an aromatic dicarboxylic acid (Ab1), and its content is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass, and particularly preferably substantially 100% by mass, based on the total amount of dicarboxylic acid (Ab).

[0032] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid, etc., or reactive derivatives such as acid anhydrides, alkyl esters, and acid halides thereof. Phthalic acid, isophthalic acid, and terephthalic acid are preferred, and these aromatic dicarboxylic acids may have a C1-C4 alkyl group and / or a C1-C4 alkoxy group on their aromatic ring. These aromatic dicarboxylic acids can be used alone or in combination of two or more. Among these, from the viewpoint of increasing the elastic modulus and hardness of the resulting coating film, it is preferable that the two carboxyl groups in the aromatic dicarboxylic acid are in a para relationship on the benzene ring, and terephthalic acid is more preferred.

[0033] The dicarboxylic acid (Ab) may include an aliphatic dicarboxylic acid (Ab2) in addition to the aromatic dicarboxylic acid (Ab1). The aliphatic dicarboxylic acid is not particularly limited, but examples include malonic acid, succinic acid, tartaric acid, oxalic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, alkylsuccinic acid, linolenic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, etc., or reactive derivatives such as acid anhydrides, alkyl esters, and acid halides thereof. These aliphatic dicarboxylic acids can be used alone or in combination of two or more. The content of the aliphatic dicarboxylic acid is 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably substantially 0% by mass, based on the total amount of dicarboxylic acid (Ab).

[0034] <Polyether polyol (G)> The polyether polyol (G) is preferably present in an amount of less than 70% by mass of the total polyol (X) constituting the polyurethane resin, more preferably in an amount of less than 60% by mass, even more preferably in an amount of 10 to 50% by mass, and particularly preferably in an amount of 10 to 40% by mass. This range is preferable because it allows for the acquisition of a highly hard coating film with low-temperature, short-time drying. Furthermore, the concentration of ether bonds in the polyurethane resin can be appropriately adjusted to the aforementioned concentrations.

[0035] The polyether polyol (G) preferably has two hydroxyl groups; in other words, it is preferably a diol. This is because the aqueous polyurethane resin dispersion composition can form a coating film with excellent hardness and adhesion without crosslinking, and therefore crosslinking is not necessarily required.

[0036] The number-average molecular weight of the polyether polyol (G) is preferably 500 to 10000, more preferably 650 to 5000, and even more preferably 900 to 3000.

[0037] The hydroxyl value of the polyether polyol (G) is preferably 11 to 225, more preferably 22 to 173, and even more preferably 37 to 125.

[0038] Examples of polyether polyols (G) include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, random copolymers and block copolymers of ethylene oxide and propylene oxide, and ethylene oxide and butylene oxide. Polyether polyol (G) may be used alone or in combination of multiple types.

[0039] The mass ratio of polyester polyol (A) to polyether polyol (G) is preferably 50:50 to 90:10, more preferably 55:45 to 80:20, and even more preferably 60:40 to 70:30. When the mass ratio is within the above range, the coating film is preferable in that it exhibits high elastic modulus while also providing good adhesion to the substrate.

[0040] <(A) component, (G) component and (C) component other than polyol (F)> Polyurethane resin may contain polyol (F) in addition to polyester polyol (A), polyether polyol (G), and acidic group-containing polyol (C) described later, as polyol (X) which can be reacted with polyisocyanate (B) described later to form a polyurethane resin. Such polyols (F) are preferably present in amounts of less than 50% by mass, more preferably less than 40% by mass, even more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass, of the total polyols (X) constituting the polyurethane resin. The type and amount of polyols (F) can be appropriately adjusted by those skilled in the art, as long as the effects of the present invention are not impaired. Other polyols (F) may not be present in the polyols.

[0041] Known polyols can be used as polyol(F). Examples include high molecular weight polyols such as polycarbonate polyols; short-chain aliphatic diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 3-methyl-1,5-pentanediol, and 2-butyl-2-ethyl-1,3-propanediol; alicyclic diols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and hydrogenated bisphenol A; and diols such as bisphenol A, hydroquinone, bishydroxyethoxybenzene, and their alkylene oxide adducts. Polyol(F) can be used alone or in combination of two or more types. Among these, high molecular weight polyols are preferred from the viewpoint of substrate adhesion and fracture energy, and polycarbonate polyols are more preferred. The polyol (F) described above may be a commercially available product or one that has been prepared individually.

[0042] The polyol (F) preferably has two hydroxyl groups; that is, it is preferably a diol. Since the aqueous polyurethane resin dispersion composition can form a coating film with excellent hardness and adhesion without crosslinking, crosslinking is not necessarily required. From the viewpoint of adhesion, it is preferable not to have crosslinking.

[0043] The number-average molecular weight of the high molecular weight polyol is preferably 500 to 10000, more preferably 650 to 5000, and even more preferably 900 to 3000.

[0044] The hydroxyl value of the high molecular weight polyol is preferably 10 to 225, more preferably 22 to 175, and even more preferably 37 to 125.

[0045] Polycarbonate polyols used as polyol (F) are obtained by reacting one or more polyol components with a carbonate ester or phosgene. From the standpoint of safety and ease of handling of reagents, and because there is no by-production of terminal chlorinated products, polycarbonate polyols obtained by reacting one or more polyol monomers with a carbonate ester are preferred.

[0046] Known polyol components can be used for polycarbonate polyols. Examples include aliphatic polyols such as linear aliphatic diols like 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, and branched aliphatic diols like 2-methyl-1,3-propanediol and 2-methyl-1,5-pentanediol; diols having an alicyclic structure in the main chain, such as 1,4-cyclohexanedimethanol; and polyester polyols and polyether polyols. The polyol component of polycarbonate polyols may be used alone or in combination of multiple types.

[0047] Polycarbonate polyols may contain fewer ether or ester bonds in their molecules than the average number of carbonate bonds in one molecule, provided that the properties of the polycarbonate polyol are not impaired.

[0048] <Polyisocyanate (B)> Known polyisocyanates (B) can be used. For example, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, 2,4-tolylenediisocyanate (TDI), 2,6-tolylenediisocyanate, 4,4'-diphenylmethanediisocyanate (MDI), 2,4-diphenylmethanediisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanate Aromatic polyisocyanates such as anatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, and p-isocyanatophenylsulfonyl isocyanate; ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), and hexamethylene diisocyanate (HDI). Aliphatic polyisocyanates such as dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate; isophorone Examples include alicyclic polyisocyanates such as diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-diclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate. Polyisocyanate (B) may have part or all of its structure derivatized by isocyanuration, carbodiimide, or biuretization. Polyisocyanate (B) may be used alone or in combination of multiple types.

[0049] Among the polyisocyanates (B) described above, alicyclic polyisocyanates are preferred from the viewpoint of substrate adhesion, isophorone diisocyanate (IPDI) and / or 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI) are more preferred from the viewpoint of hardness and fracture energy, and 4,4'-dicyclohexylmethane diisocyanate is even more preferred. In polyisocyanate (B), the alicyclic polyisocyanate is preferably in an amount of 50 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass.

[0050] Polyisocyanate (B) may be used alone or in combination of multiple types. It is preferable that polyisocyanate (B) does not contain blocked isocyanates. This is because, when the aqueous polyurethane resin dispersion composition is used as a coating film, it hardens at low temperatures, and therefore blocked isocyanates, which require high temperatures to release the block and activate the isocyanate, are unsuitable.

[0051] The amount of polyisocyanate (B) used is preferably such that the ratio of isocyanate groups of polyisocyanate (Ab) to hydroxyl groups of the total polyol (the sum of polyester polyol (A), polyether polyol (G), any polyol (F), and any acidic group-containing polyol (C)) is 1.5 to 2.5, and particularly preferably 1.6 to 2.1.

[0052] <Acidic group-containing polyol (C)> An acidic group-containing polyol (C) is one that contains two or more hydroxyl groups and one or more acidic groups in a single molecule. An acidic group-containing polyol (C) may be used alone or in combination of multiple types.

[0053] As the acidic group-containing polyol (C), known polyols can be used. For example, dimethylolalkanoates such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid; N,N-bishydroxyethylglycine, N,N-bishydroxyethylalanine, 3,4-dihydroxybutanesulfonic acid, and 3,6-dihydroxy-2-toluenesulfonic acid are examples. Among these, dimethylolalkanoates with 4 to 12 carbon atoms containing two methylol groups are preferred from the viewpoint of ease of availability, and among dimethylolalkanoates, 2,2-dimethylolpropionic acid is more preferred.

[0054] From the viewpoint of resin dispersibility, the acidic group-containing polyol (C) is preferably present in an amount of 4 to 20% by mass, more preferably in an amount of 8 to 18% by mass, even more preferably in an amount of 10 to 16% by mass, and particularly preferably in an amount of 12 to 15% by mass, of the total polyol (X) constituting the polyurethane resin.

[0055] In an aqueous polyurethane resin dispersion composition, the total hydroxyl group equivalent number of polyester polyol (A), polyether polyol (G), acidic group-containing polyol (C), and polyol (F) is preferably 50 to 4000. If the hydroxyl group equivalent number is within this range, the aqueous polyurethane resin dispersion composition containing the obtained polyurethane resin is easily manufactured. From the viewpoint of the rupture energy of the coating film obtained from the resulting aqueous polyurethane resin dispersion composition, the hydroxyl group equivalent number is preferably 100 to 2500, more preferably 120 to 1500, and particularly preferably 150 to 1000.

[0056] The hydroxyl group equivalents can be calculated using the following formulas (1) and (2). Number of hydroxyl groups equivalent to each polyol component = Molecular weight of each polyol component / Number of hydroxyl groups in each polyol component ... (1) Total hydroxyl group equivalents of polyol components = M / Total number of moles of polyol components ... (2) In equation (2), M represents [number of hydroxyl group equivalents of polyester polyol (A) × number of moles of polyester polyol (A)] + [number of hydroxyl group equivalents of polyether polyol (G) × number of moles of polyether polyol (G)] + [number of hydroxyl group equivalents of acidic group-containing polyol (C) × number of moles of acidic group-containing polyol (C)] + [number of hydroxyl group equivalents of polyol (F) × number of moles of polyol (F)].

[0057] <Neutralizing agent (D)> The neutralizing agent (D) may be used alone or in combination of multiple types.

[0058] As the neutralizing agent (D), known substances can be used. For example, non-volatile bases such as sodium hydroxide and potassium hydroxide; tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine; secondary amines such as dimethylamine, diethylamine, and dibutylamine; primary amines such as ethylenediamine, methylamine, ethylamine, and butylamine; and ammonia can be used.

[0059] The neutralizing agent (D) described above preferably has a boiling point of 200°C or lower, and more preferably in the range of -50 to 180°C, since it volatilizes at the temperature during drying of the aqueous medium in the coating material composition (usually 50 to 180°C) and disappears from the polyurethane film, thereby obtaining even higher hardness. When obtaining a dried coating film in a short time of a few seconds to 1 hour at a low temperature of 100°C or lower, its boiling point preferably has a boiling point of 130°C or lower, and more preferably has a boiling point of 110°C or lower.

[0060] When using the neutralizing agent (D) described above, the amount used is preferably in the range of 0.8 to 1.2 times the number of moles of acidic groups in the acidic group-containing polyol (C) contained in the aqueous polyurethane resin dispersion composition. If the amount of the neutralizing agent (D) used is 0.8 times or more the number of moles of acidic groups contained in the aqueous polyurethane resin dispersion composition, the stability of the resulting dispersion is high, and if it is 1.2 times or less, a coating film with high hardness, substrate adhesion, and fracture energy can be obtained in a short time of a few seconds to 10 minutes under low-temperature drying conditions of 100°C or below.

[0061] <Chain extender (E)> The chain extender (E) is a compound that reacts with the isocyanate group of the polyurethane prepolymer. The chain extender (E) may be used alone or in combination of multiple types. In this specification, polyols that also function as chain extenders are not included in chain extender (E) but are included in polyol (X).

[0062] Known substances can be used as the chain extender (E). Examples include amines such as ethylenediamine, 1,4-tetramethylenediamine, 2-methyl-1,5-pentanediamine, 1,4-butanediamine, 1,6-hexamethylenediamine, 1,4-hexamethylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3-bis(aminomethyl)cyclohexane, xylylenediamine, piperazine, 2,5-dimethylpiperazine, and aminoethylethanolamine; and water, with amines being preferred.

[0063] Among the above chain extenders (E), diamines with a number-average molecular weight (Mn) of 300 or less are preferred. Having a Mn of 300 or less is necessary to increase the cohesive strength of the polyurethane resin, and the use of diamines is preferable not only for increasing the Mn of the polyurethane resin and improving its durability, but also from the viewpoint of rupture energy.

[0064] The amount of the chain extender (E) added is preferably less than or equal to the equivalent amount of isocyanate groups that serve as chain extension starting points in the resulting urethane polymer. If the amount of chain extender (E) added exceeds the equivalent amount of isocyanate groups, the molecular weight of the chain-extended urethane polymer may decrease, reducing its cohesive force and potentially lowering its breaking energy.

[0065] In addition to the examples above, the chain extender (E) may also be a compound having three or more functional groups that are reactive with isocyanate groups. By using such a compound, it becomes easier to control the content of N(C=O)NH groups. As a result, it becomes easier to control the drying rate when forming a coating film. Examples of such compounds include polyamines having a total of three or more amino groups and / or imino groups in one molecule, and compounds such as diethylenetriamine can be used.

[0066] <<Polyurethane resin>> <Aromatic ring> The polyurethane resin has aromatic rings, and the aromatic ring content in the polyurethane resin is 4% to 18% by mass, preferably 5% to 16% by mass, and more preferably 7% to 14% by mass. By setting the range within this range, the elastic modulus of the polyurethane resin coating can be increased. The proportion of aromatic rings in a polyurethane resin indicates the content of aromatic rings relative to the total amount of constituent components of the polyurethane resin. For example, if a polyurethane resin contains constituent components derived from polyester polyol (A), polyisocyanate (B), acidic group-containing polyol (C), chain extender (E), polyol (F), and polyether polyol (G), the proportion of aromatic rings in the raw materials is indicated relative to the total mass of these raw materials used in the manufacture. The molecular weight of the aromatic ring shall be the molecular weight of the benzene ring or naphthalene ring excluding the organic group. For example, the proportion of aromatic rings in a polyurethane resin made from raw materials containing a benzene ring structure without an organic group can be determined from the following formula (1). Equation (1): Aromatic ring structure content (mass%) = 100 × (atomic weight of carbon × 6 + atomic weight of hydrogen × 4) × {(moles of polyester polyol (A)) × (number of aromatic rings contained in polyester polyol (A)) + (moles of polyisocyanate (B)) × (number of aromatic rings contained in polyisocyanate (B)) + (moles of acidic group-containing polyol (C)) × (number of aromatic rings contained in acidic group-containing polyol (C)) + (moles of chain extender (E)) × (number of aromatic rings contained in chain extender (E)) + (moles of polyol (F)) × (number of aromatic rings contained in polyol (F)) + (moles of polyether polyol (G)) × (number of aromatic rings contained in polyether polyol (G))} / (mass of polyurethane resin [g]) At least one component selected from the group consisting of a component derived from polyester polyol (A), a component derived from polyether polyol (G), and a component derived from polyisocyanate (B) has an aromatic ring. Furthermore, a component derived from any acidic group-containing polyol (C), a component derived from any chain extender (E), and a component derived from any polyol (F) may also have an aromatic ring.

[0067] <Ether bond> The polyurethane resin has ether bonds, and the content of ether bonds in the polyurethane resin is 0.5% to 10% by mass, preferably 0.8% to 8% by mass, more preferably 1.5% to 6% by mass, and even more preferably 2% to 5% by mass. By defining this range, the adhesion of the polyurethane resin coating can be improved. The proportion of ether groups in polyurethane resin indicates the content of ether groups relative to the total amount of constituent components of the polyurethane resin. For example, if the polyurethane resin contains constituent components derived from polyester polyol (A), polyisocyanate (B), acidic group-containing polyol (C), chain extender (E), polyol (F), and polyether polyol (G), the proportion of ether groups in the raw materials is indicated relative to the total mass of these raw materials used in the manufacture. The proportion of ether bonds in polyurethane resin can be determined from the following formula (2). The content of ether bonds (mass%) can be calculated using the formula (2): ether bond content (mass%) = 100 × (atomic weight of oxygen × 1) × {(moles of polyester polyol (A)) × (number of ether bonds contained in polyester polyol (A)) + (moles of polyisocyanate (B)) × (number of ether bonds contained in polyisocyanate (B)) + (moles of acidic group-containing polyol (C)) × (number of ether bonds contained in acidic group-containing polyol (C)) + (moles of chain extender (E)) × (number of ether bonds contained in chain extender (E)) + (moles of polyol (F)) × (number of ether bonds contained in polyol (F)) + (moles of polyether polyol (G)) × (number of ether bonds contained in polyether polyol (G))} / (mass of polyurethane resin [g]). The constituent units derived from polyether polyol (G) have ether bonds. In addition, constituent units derived from polyester polyol (A), polyisocyanate (B), any acidic group-containing polyol (C), any chain extender (E), and any polyol (F) may also have ether bonds.

[0068] The polyurethane resin in the aqueous polyurethane resin dispersion composition of the present invention preferably has the following characteristics. The number-average molecular weight (Mn) of the polyurethane resin is preferably 50,000 or more, and more preferably 100,000 or more, from the viewpoint of the rupture energy of the low-temperature dried coating film. By setting the number-average molecular weight to 50,000 or more, the coating film obtained by drying the composition at a temperature of 100°C or below exhibits a superior rupture energy. There is no particular upper limit as long as it can be synthesized and has a viscosity that allows it to be handled as an aqueous dispersion. The upper limit of the number-average molecular weight is usually 2,000,000 or less, and preferably 1,000,000 or less.

[0069] The weight-average molecular weight (Mw) of the polyurethane resin is preferably 100,000 or more, and more preferably 400,000 or more. A weight-average molecular weight within the above range is preferable from the viewpoint of the rupture energy of the coating film.

[0070] The acid value of the polyurethane resin is not particularly limited, but is preferably 18-40 mgKOH / g on a solid content basis, and more preferably 20-35 mgKOH / g. When the acid value of the polyurethane resin is greater than 40 mgKOH / g on a solid content basis, the dispersibility in aqueous media tends to deteriorate. When the acid value is less than 18 mgKOH / g on a solid content basis, the adhesion to the substrate tends to decrease. The acid value can be measured in accordance with the indicator titration method of JIS K 1557. In the measurement, the neutralizing agent used to neutralize the acidic group should be removed before measurement. For example, when organic amines are used as neutralizing agents, the aqueous polyurethane resin dispersion composition can be applied to a glass plate, dried at 60°C under reduced pressure of 20 mmHg for 24 hours, and the resulting coating film can be dissolved in N-methylpyrrolidone (NMP) and the acid value can be measured in accordance with the indicator titration method of JIS K 1557.

[0071] <Aqueous polyurethane resin dispersion composition> The aqueous polyurethane resin dispersion composition comprises the polyurethane resin and an aqueous medium, wherein the polyurethane resin is dispersed in the aqueous medium. Examples of aqueous media include tap water, deionized water, distilled water, ultrapure water, and mixed media of water and hydrophilic organic solvents. Examples of hydrophilic organic solvents include ketones such as acetone and ethyl methyl ketone; pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone; ethers such as diethyl ether and dipropylene glycol dimethyl ether; alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, and diethylene glycol; amides such as β-alkoxypropionamide, typified by KJ Chemical's "KJCMPA(R)-100"; and hydroxyl-containing tertiary amines such as 2-(dimethylamino)-2-methyl-1-propanol (DMAP).

[0072] The amount of hydrophilic organic solvent in the aqueous medium is preferably 0 to 20% by mass, more preferably 0 to 15% by mass, and even more preferably 0 to 10% by mass.

[0073] The pH of the aqueous polyurethane resin dispersion composition is preferably 5.0 to 10.0, more preferably 6.0 to 9.5, and even more preferably 6.5 to 9.0.

[0074] The proportion of polyurethane resin in the aqueous dispersion is preferably 5 to 60% by mass, more preferably 20 to 50% by mass.

[0075] <Method for producing aqueous polyurethane resin dispersion composition> Aqueous polyurethane resin dispersion compositions can be produced by known methods described in International Publication No. 2016 / 039396, etc. For example, the following production methods can be used. The first manufacturing method involves mixing all the raw materials, reacting them, and dispersing them in an aqueous medium to obtain an aqueous polyurethane resin dispersion composition. The second manufacturing method involves reacting the entire polyol component with a polyisocyanate to produce a prepolymer, neutralizing the acidic groups of the prepolymer, dispersing it in an aqueous medium, and reacting it with a chain extender to obtain an aqueous polyurethane resin dispersion composition. As a method for producing the aqueous polyurethane resin dispersion composition, the second method described above is preferred because it allows for easy control of the molecular weight.

[0076] In particular, in the present invention, an aqueous polyurethane resin dispersion composition can be produced by a method comprising the following (I) to (IV) and optionally (V). (I) A step of reacting a polyester polyol (A), a polyether polyol (G), a polyisocyanate (B), an arbitrary acidic group-containing polyol (C), and an arbitrary polyol (F) in the presence or absence of an organic solvent to obtain a polyurethane prepolymer. (II) A step of neutralizing the acidic groups of the polyurethane prepolymer with a neutralizing agent (D), (III) A step of dispersing the polyurethane prepolymer in an aqueous medium, (IV) A step of increasing the molecular weight of the polyurethane prepolymer with a chain extender (E), and optionally, (V) Step to remove organic solvents.

[0077] [Second aspect of the present invention] A second aspect of the present invention is an aqueous polyurethane resin dispersion composition comprising two or more polyurethane resins and an aqueous medium, At least one polyurethane resin (I) has constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), and constituent units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin. At least one polyurethane resin (II) has constituent units derived from polyether polyol (G) and constituent units derived from polyisocyanate (B), This aqueous polyurethane resin dispersion composition contains 4% to 18% by mass of aromatic rings and 0.5% to 10% by mass of ether bonds in the total polyurethane resin.

[0078] Preferably, both polyurethane resins (I) and (II) further contain constituent units derived from an acidic group-containing polyol (C), constituent units derived from a chain extender (E), and constituent units derived from a polyol (F) other than components (A), (G), and (C).

[0079] Examples of the polyol (Aa) and dicarboxylic acid (Ab) components of the polyester polyol (A) in the polyurethane resin (I) are the same as those in the first embodiment of the present invention. Examples of the polyester polyol (A) in the polyurethane resin (I) include those similar to those in the first embodiment of the present invention. The polyester polyol (A) content in the polyurethane resin (I) is adjusted as appropriate so that the aromatic ring content in the total polyurethane resin is 4% to 18% by mass, and the ether bond content is 0.5% to 10% by mass.

[0080] Examples of the polyisocyanate (B) in the polyurethane resin (I) include those similar to those in the first embodiment of the present invention. In polyurethane resin (I), the amount of polyisocyanate (B) used is preferably such that the ratio of isocyanate groups of polyisocyanate (Ab) to hydroxyl groups of total polyol (Y) (isocyanate groups / hydroxyl groups (molar ratio)) is 1.7 to 2.5, and particularly preferably 1.75 to 2.3. Total polyol (Y) refers to the total polyols constituting polyurethane resin (I).

[0081] Examples of the acidic group-containing polyol (C), neutralizing agent (D), chain extender (E), and polyol (F) in the polyurethane resin (I) are the same as those in the first embodiment of the present invention. In the polyurethane resin (I), the acidic group-containing polyol (C) is preferably 4 to 20% by mass, more preferably 8 to 18% by mass, even more preferably 10 to 16% by mass, and particularly preferably 12 to 15% by mass, of the total polyol (Y) constituting the polyurethane resin (I). Within this range, a stable aqueous dispersion can be obtained.

[0082] The polyol (F) in the polyurethane resin (I) is appropriately adjusted so that the aromatic ring content in the total polyurethane resin is 4% to 18% by mass, and the ether bond content is 0.5% to 10% by mass. Furthermore, the content relative to the total amount of two or more polyurethane resins is also adjusted to be within the same range as in the first embodiment.

[0083] Polyurethane resin (I) has aromatic rings. In polyurethane resin (I), at least one selected from the group consisting of constituent units derived from polyester polyol (A) and constituent units derived from polyisocyanate (B) has an aromatic ring. Furthermore, constituent units derived from any acidic group-containing polyol (C), any chain extender (E), and any polyol (F) may have aromatic rings. It is preferable that polyurethane resin (I) does not have ether bonds.

[0084] Examples of the polyether polyol (G) in the polyurethane resin (II) include those similar to those in the first embodiment of the present invention. The polyether polyol (G) content in the polyurethane resin (I) is adjusted as appropriate so that the aromatic ring content in the total polyurethane resin is 4% to 18% by mass, and the ether bond content is 0.5% to 10% by mass.

[0085] Examples of polyisocyanate (B) in polyurethane resin (II) include those similar to those in the first embodiment of the present invention. In polyurethane resin (II), the amount of polyisocyanate (B) used is preferably such that the ratio of isocyanate groups of polyisocyanate (Ab) to hydroxyl groups of the total polyol (Z) (isocyanate groups / hydroxyl groups (molar ratio)) is 1.7 to 2.5, and particularly preferably 1.75 to 2.3.

[0086] Examples of the acidic group-containing polyol (C), neutralizing agent (D), chain extender (E), and polyol (F) in the polyurethane resin (II) are the same as those in the first embodiment of the present invention. In the polyurethane resin (II), the acidic group-containing polyol (C) is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 2 to 8% by mass, of the total polyol (Z) constituting the polyurethane resin (II). Within this range, a coating film with high drying properties can be obtained.

[0087] In polyurethane resin (II), the polyol (F) is appropriately adjusted so that the aromatic ring content in the polyurethane resin is 4% to 18% by mass, and the ether bond content is 0.5% to 10% by mass.

[0088] Polyurethane resin (II) has ether bonds. Constituent units derived from polyether polyol (G) have ether bonds. Constituent units derived from polyisocyanate (B), constituent units derived from any acidic group-containing polyol (C), constituent units derived from any chain extender (E), and constituent units derived from any polyol (F) may have ether bonds. It is preferable that polyurethane resin (II) does not have aromatic rings.

[0089] The aqueous polyurethane resin dispersion composition, comprising two or more polyurethane resins including polyurethane resin (I) and polyurethane resin (II) and an aqueous medium, has an aromatic ring content of 4% to 18% by mass, preferably 5% to 16% by mass, and more preferably 7% to 14% by mass, in the total polyurethane resin. By setting the content within this range, the elastic modulus of the polyurethane resin coating can be increased.

[0090] The aqueous polyurethane resin dispersion composition, comprising two or more polyurethane resins including polyurethane resin (I) and polyurethane resin (II) and an aqueous medium, has an ether bond content of 0.5% to 10% by mass, preferably 0.8% to 8% by mass, more preferably 1.5% to 6% by mass, and even more preferably 2% to 5% by mass in the total polyurethane resin. By setting the content within this range, the adhesion of the polyurethane resin coating can be improved. The aqueous medium, polyurethane resin content, and pH of the aqueous polyurethane resin dispersion composition are the same as in the first embodiment of the present invention.

[0091] A method for producing aqueous polyurethane resin dispersion compositions can be used to produce aqueous polyurethane resin dispersions by known methods described in International Publication No. 2016 / 039396, etc. For example, the following production methods can be used. The first manufacturing method involves mixing all the raw materials with polyurethane resin (I) and polyurethane resin (II), reacting them, and dispersing the mixture in an aqueous medium to obtain an aqueous polyurethane resin dispersion. The second manufacturing method involves reacting polyurethane resin (I) and polyurethane resin (II) with the total polyol component and polyisocyanate to produce a prepolymer, neutralizing the acidic groups of the prepolymer, dispersing it in an aqueous medium, and reacting it with a chain extender to obtain an aqueous polyurethane resin dispersion. As a method for producing an aqueous polyurethane resin dispersion, the second method described above is preferred because it allows for easy control of the molecular weight. Specifically, the aqueous polyurethane resin dispersion composition of the present invention can also be obtained by mixing an aqueous polyurethane resin dispersion containing polyurethane resin (I) as the polyurethane resin with an aqueous polyurethane resin dispersion containing polyurethane resin (II) as the polyurethane resin. In this case, the mixing ratio is adjusted so that the content of aromatic rings and ether groups contained in the total polyurethane resin falls within the aforementioned range. When mixing three or more aqueous polyurethane resin dispersions, the aromatic rings and ether groups are also adjusted to fall within the aforementioned range.

[0092] <Manufacturing of coating material compositions> The aqueous polyurethane resin dispersion composition is used in coating material compositions. In this specification, a coating material composition refers to a material that forms a coating film when applied to an electrodeposited surface, steel plate, wood, or plastic substrate using a spray, brush, applicator, bar coater, or the like.

[0093] The coating material composition contains the aqueous polyurethane resin dispersion composition as an essential component, but may also contain other resins and / or other additives as needed. Hereinafter, when the term "coating material composition" is used in this specification, it includes not only compositions containing other resins, additives, etc., but also compositions consisting solely of the aqueous polyurethane resin dispersion composition.

[0094] Examples of the aforementioned other resins include acrylic resins, olefin resins, polyester resins, vinyl chloride resins, and nylon resins in emulsion form. Among these, acrylic emulsions, polyolefin emulsions, and polyester emulsions are preferred, and a coating material composition obtained by mixing at least one of these as an optional component is preferred.

[0095] Other additives that can be used include, for example, film-forming aids, curing agents, crosslinking agents, surface modifiers, emulsifiers, thickeners, urethane catalysts, fillers, foaming agents, pigments, dyes, oil repellents, hollow foams, flame retardants, defoamers, leveling agents, and anti-blocking agents. These additives may be used individually or in combination of two or more.

[0096] As a surface modifier, any substance that can eliminate defects in the coating film caused by changes in viscosity, surface tension, and foam formation associated with high molecular weight can be used without particular limitations. Examples include various surface modifiers, leveling agents, wetting agents, and defoaming agents such as acrylic, vinyl, silicone, fluorine, cellulose, natural wax, and water-soluble organic solvents, as well as surfactants, with wetting agents being particularly preferred.

[0097] Glycol ethers are an example of film-forming aids.

[0098] The method for producing the coating material composition is not particularly limited, but known production methods can be used. For example, it can be produced by stirring and mixing the aqueous polyurethane resin dispersion composition, as an optional component, other resins and various additives as described above.

[0099] In the coating material composition, the mixing ratio of the aqueous polyurethane resin dispersion composition to other resins is preferably 100 / 0 to 10 / 90 (solids mass ratio), more preferably 100 / 0 to 15 / 85, even more preferably 90 / 10 to 20 / 80, and particularly preferably 80 / 20 to 30 / 70, from the viewpoint of substrate adhesion and fracture energy.

[0100] <Curing method> The coating material composition can be cured by heating it to a temperature of 20°C or higher, preferably 100°C or lower, and more preferably 80°C or lower. Specifically, the coating material composition can be applied to various plastic substrates such as electrodeposited surfaces, steel plates, wood, polycarbonate resin, acrylic resin, polyethylene terephthalate (PET) resin, and acrylonitrile butadiene styrene (ABS) resin using a spray, brush, applicator, bar coater, etc., and cured by holding it in an oven or heating bath at 100°C or lower, preferably 80°C, for 1 to 120 minutes, preferably 1 to 60 minutes, more preferably 1 to 45 minutes, and even more preferably 1 to 20 minutes. The dry film thickness of the coating film is preferably adjusted to 0.5 to 200 μm, more preferably 1 to 100 μm, even more preferably 5 to 50 μm, and particularly preferably 10 to 40 μm. When used as a primer, base coat, etc. in a multi-layer coating, after applying it to the various substrates mentioned above, for example, it can be held at room temperature to 80°C for 1 to 30 minutes, preferably 1 to 10 minutes, more preferably 2 to 6 minutes, and then another base coat can be applied as an optional component. After drying at the same drying temperature and time, a top coat (referred to as a clear coat depending on the application) can be applied and then heat-cured at 100°C or below, preferably 80°C or below, for 10 to 120 minutes, preferably 20 to 90 minutes, more preferably 30 to 60 minutes. One aspect of the present invention is a coating film obtained by applying a coating material composition and then drying it at 20°C to 100°C.

[0101] <Physical properties of the coating film> The coating material composition can be dried after application to obtain a coating film. The breaking energy of the coating film obtained from the coating material composition, as measured by the method described in the examples, is preferably 100 MPa or higher, more preferably 110 MPa or higher, and even more preferably 120 MPa or higher. The above values ​​can be achieved, for example, in an embodiment in which polyol (F) is used and polyester polyol (A) and polyol (F) are within a specific range.

[0102] The adhesion of the coating film obtained from the coating material composition to the electrodeposited surface, as measured by the method described in the Examples, is preferably 80 / 100 or higher, and more preferably 100 / 100. Here, in the present invention, the evaluation of the adhesion of the coating film is expressed as "n / 100". n means the number of squares remaining when at least one square peeled off under the test conditions described below. The conditions for the adhesion test are described in detail in the Examples section. The above values ​​can be achieved, for example, in an embodiment in which polyol (F) is used and polyester polyol (A) and polyol (F) are within a specific range.

[0103] The measured König hardness of a 13-15 μm coating film obtained by drying a coating film from a coating material composition at 80°C for 10 minutes using the method described in the examples is preferably greater than 120, and more preferably 123 or higher.

[0104] The elastic modulus of the coating film obtained from the coating material composition of the present invention, as measured by the method described in the examples, is preferably 1400 MPa or higher, more preferably 1500 MPa or higher, and even more preferably 2000 MPa or higher.

[0105] <Application> The coating material composition can be suitably used as a primer material, a base coat material, and a fracture-resistant material. In this specification, a fracture-resistant material refers to a material used as a protective agent for a substrate and which itself has properties that make it difficult to break against physical impacts such as collisions, flying stones, and drops. The coating material composition containing the aqueous polyurethane resin dispersion composition of the present invention can be suitably used as a fracture-resistant material.

[0106] The primer materials, base coat materials, and fracture-resistant materials are useful for a wide range of applications, including floor coatings, coatings for various plastic substrates such as polycarbonate resin, acrylic resin, polyethylene terephthalate (PET) resin, and acrylonitrile butadiene styrene (ABS) resin, as well as coatings for rubber, steel plate treatment agents, and primers or base coats for metal exteriors such as automobiles, trucks, and trains. They are particularly useful for use as primers or base coats for metal exteriors.

[0107] [Third aspect of the present invention] A third aspect of the present invention has a constituent unit derived from a polyester polyol (A) comprising a polyol (Aa) and a dicarboxylic acid (Ab), a constituent unit derived from a polyether polyol (G), and a constituent unit derived from a polyisocyanate (B), At least one selected from the group consisting of the constituent units derived from the polyester polyol (A), the constituent units derived from the polyether polyol (G), and the constituent units derived from the polyisocyanate (B) has an aromatic ring, This polyurethane resin contains 4% to 18% by mass of aromatic rings and 0.5% to 10% by mass of ether groups. The polyurethane resin, its constituent units, and manufacturing method are the same as those of the polyurethane resin in the aqueous polyurethane resin dispersion composition of the first aspect of the present invention. This polyurethane resin forms a coating film. The physical properties and applications of this coating film are the same as those of the coating film of the coating material composition described above.

[0108] [Fourth aspect of the present invention] A polyurethane resin composition comprising two or more types of polyurethane resins, At least one polyurethane resin has constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), and constituent units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin. At least one polyurethane resin has constituent units derived from polyether polyol (G) and constituent units derived from polyisocyanate (B), A polyurethane resin composition in which the total polyurethane resin contains 4% to 18% by mass of aromatic rings and 0.5% to 10% by mass of ether bonds. The constituent units of the polyurethane resin in this polyurethane resin composition and the method of production are the same as those of the polyurethane resin in the aqueous polyurethane resin dispersion composition of the second aspect of the present invention. This polyurethane resin forms a coating film. The physical properties and applications of this coating film are the same as those of the coating film of the coating material composition described above. [Examples]

[0109] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto. The following physical property measurements were performed.

[0110] (1) The weight-average molecular weight of the polyurethane resin in the aqueous polyurethane resin dispersion composition was measured by gel permeation chromatography (GPC), and the converted value obtained from a pre-prepared calibration curve of standard polystyrene is indicated. (2) The acid value was measured in accordance with the indicator titration method of JIS K 1557.

[0111] (3) The König hardness of the coating film was evaluated as follows: Dipropylene glycol n-butyl ether (Dawanol® DPnB, manufactured by Ando Parachemy) was added to each aqueous polyurethane resin dispersion composition as a film-forming aid at a concentration of 2% by mass, and a silicone-based surfactant (BYK-345, manufactured by Bic Chemie) was added at a concentration of 0.5% by mass. The resulting coating material composition was then uniformly applied to an automotive cationic electrodeposition coating board manufactured by Nippon Test Panel using a bar coater #20. The coating was then dried at 80°C for 10 minutes. The thickness of the resulting coating film was 13-15 μm. In the laminate of the electrodeposition coating board and the polyurethane resin coating obtained above, the König hardness of the polyurethane resin coating was measured in accordance with ISO 1522.

[0112] (4) The adhesion of the coating film to the electrodeposited layer surface was evaluated as follows: A coating material composition was prepared by adding 2% by mass of Dawanol® DPnB as a film-forming aid and 0.5% by mass of a silicone-based surfactant (BYK-345, manufactured by BYChemie Inc.) to an aqueous polyurethane resin dispersion composition and mixing the mixture. This composition was applied to an automotive steel sheet cation electrodeposited plate (manufactured by Nippon Test Panel Co., Ltd.) using a bar coater #18, heated and dried at 80°C for 45 minutes, and a grid peel test was performed using the obtained coating film. Cuts were made in the coating film at 1 mm intervals vertically and horizontally over an area of ​​10 mm × 10 mm, and after applying adhesive tape and peeling it off, the number of squares remaining on the electrodeposited layer surface was visually counted and evaluated. For example, if 15 out of 100 squares remained in the peel test, it was recorded as 15 / 100.

[0113] (5) The tensile properties of the coating film were evaluated as follows. A coating material composition was prepared by adding 4.7% by mass of Dawanol® DPnB as a film-forming aid and 0.5% by mass of a silicone-based surfactant (BYK-345, manufactured by BYK Chemie) to an aqueous polyurethane resin dispersion composition and mixing the mixture. This composition was then applied to a PET film to a dry film thickness of 70 μm. The film was then left at room temperature for 15 hours, dried at 60°C for 2 hours, and then at 120°C for another 2 hours to create the coating film. The elastic modulus of the polyurethane resin film was measured according to the method in accordance with JIS K 7311. The rupture energy of the coating film was determined by integrating the stress from zero elongation to the rupture point elongation on the elongation-stress curve. The measurement conditions were a measurement temperature of 23°C, humidity of 50%, and a tensile speed of 100 mm / min.

[0114] (6) The proportion of aromatic rings and ether bonds in the polyurethane resin was determined from the amount charged using the following formula. Aromatic ring structure content (mass%) = 100 × (atomic weight of carbon × 6 + atomic weight of hydrogen × 4) × {(moles of polyester polyol (A)) × (number of aromatic rings contained in polyester polyol (A)) + (moles of polyisocyanate (B)) × (number of aromatic rings contained in polyisocyanate (B)) + (moles of acidic group-containing polyol (C)) × (number of aromatic rings contained in acidic group-containing polyol (C)) + (moles of chain extender (E)) × (number of aromatic rings contained in chain extender (E)) + (moles of polyol (F)) × (number of aromatic rings contained in polyol (F)) + (moles of polyether polyol (G)) × (number of aromatic rings contained in polyether polyol (G))} / (mass of polyurethane resin [g]) Ether bond content (mass%) = 100 × (atomic weight of oxygen × 1) × {(moles of polyester polyol (A)) × (number of ether bonds in polyester polyol (A)) + (moles of polyisocyanate (B)) × (number of ether bonds in polyisocyanate (B)) + (moles of acidic group-containing polyol (C)) × (number of ether bonds in acidic group-containing polyol (C)) + (moles of chain extender (E)) × (number of ether bonds in chain extender (E)) + (moles of polyol (F)) × (number of ether bonds in polyol (F)) + (moles of polyether polyol (G)) × (number of ether bonds in polyether polyol (G))} / (mass of polyurethane resin [g]) (7) The number-average molecular weight and hydroxyl value of the raw materials are catalog values.

[0115] [Manufacturing Example 1] <Production of aqueous polyurethane resin dispersion composition (1)> Polyester polyol HS (registered trademark) 2F-136P (manufactured by Toyokuni Oil Co., Ltd.; LOT. GL7832; number average molecular weight 1079; hydroxyl value 104.0 mg KOH / g; acid value 0.81; polyester polyol obtained by dehydration condensation of neopentyl glycol and terephthalic acid, 152 g), polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical Corporation; number average molecular weight 1955; hydroxyl value 57.4 mg KOH / g, 38.0 g), 2,2-dimethylolpropionic acid (28.0 g), and 4,4'-dicyclohexylmethane diisocyanate (181.6 g) were heated in dipropylene glycol dimethyl ether (DMM, 102.2 g) in the presence of dibutyltin dilaurine (0.0606 g) under a nitrogen atmosphere at 80-85°C for 4 hours. The reaction mixture was cooled to 80°C, and 362.7g of the mixture, to which triethylamine (21.1g) was added and mixed, was added to water (569.6g) under vigorous stirring. Then, 35% by mass of an aqueous solution of 2-methyl-1,5-pentanediamine (60.6g) and 35% by mass of 2-(2-aminoethylamino)ethanol (8.0g) were added to obtain aqueous polyurethane resin dispersion composition (1) (weight-average molecular weight of polyurethane resin: 460,000, acid value: 27.0).

[0116] [Manufacturing Example 2] <Production of aqueous polyurethane resin dispersion composition (2)> Polyester polyol HS (registered trademark) 2F-136P (manufactured by Toyokuni Oil Co., Ltd.; LOT. GL7832; number average molecular weight 1079; hydroxyl value 104.0 mg KOH / g; acid value 0.81; polyester polyol obtained by dehydration condensation of neopentyl glycol and terephthalic acid, 117.0 g), polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical Corporation; number average molecular weight 1955; hydroxyl value 57.4 mg KOH / g, 78.2 g), 2,2-dimethylolpropionic acid (27.8 g), and 4,4'-dicyclohexylmethane diisocyanate (175.3 g) were heated in dipropylene glycol dimethyl ether (DMM, 101.1 g) in the presence of dibutyltin dilaurine (0.0817 g) under a nitrogen atmosphere at 80-85°C for 5 hours. The reaction mixture was cooled to 80°C, and 364.5g of the mixture, to which triethylamine (20.6g) was added and mixed, was added to water (572.5g) under vigorous stirring. Then, 35% by mass of an aqueous solution of 2-methyl-1,5-pentanediamine (56.0g) and 35% by mass of 2-(2-aminoethylamino)ethanol (8.0g) were added to obtain aqueous polyurethane resin dispersion composition (2) (weight-average molecular weight of polyurethane resin: 790,000, acid value: 27.0).

[0117] [Manufacturing Example 3] <Production of aqueous polyurethane resin dispersion composition (3)> Polyester polyol HS (registered trademark) 2F-136P (manufactured by Toyokuni Oil Co., Ltd.; LOT. GL0734; number average molecular weight 1090; hydroxyl value 103.0 mg KOH / g; acid value 0.74; polyester polyol obtained by dehydration condensation of neopentyl glycol and terephthalic acid, 96.1 g), polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical Corporation; number average molecular weight 1955; hydroxyl value 57.4 mg KOH / g, 64.1 g), 2,2-dimethylolpropionic acid (36.9 g), and 4,4'-dicyclohexylmethane diisocyanate (195.2 g) were heated in dipropylene glycol dimethyl ether (DMM, 100.0 g) in the presence of dibutyltin dilaurine (0.1536 g) under a nitrogen atmosphere at 80-85°C for 5 hours. The reaction mixture was cooled to 80°C, and 365.5g of the mixture, to which triethylamine (27.3g) was added and mixed, was added to water (562.5g) under vigorous stirring. Then, 35% by mass of 2-methyl-1,5-pentanediamine aqueous solution (57.2g) and 35% by mass of 2-(2-aminoethylamino)ethanol (15.9g) were added to obtain aqueous polyurethane resin dispersion composition (3) (weight-average molecular weight of polyurethane resin 870,000, acid value 36.0).

[0118] [Manufacturing Example 4] <Production of aqueous polyurethane resin dispersion composition (4)> Polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical; number average molecular weight 1968; hydroxyl value 57.0 mgKOH / g, 50.5 kg), 2,2-dimethylolpropionic acid (1.9 kg), and isophorone diisocyanate (12.6 kg) were heated in dipropylene glycol dimethyl ether (DMM, 18.5 kg) under a nitrogen atmosphere at 80-90°C for 7.5 hours. The reaction mixture was cooled to 80°C, and triethylamine (1.5 kg) was added and mixed. 79.7 kg of this mixture was then added to water (126.1 kg) under vigorous stirring. Next, piperazine (1.2 kg) was added to form aqueous polyurethane resin dispersion composition (4) (weight average molecular weight of polyurethane resin 880000, acid value 12.2).

[0119] [Manufacturing Example 5] <Production of aqueous polyurethane resin dispersion composition (5)> Polyester polyol HS (registered trademark) 2F-136P (manufactured by Toyokuni Oil Co., Ltd.; LOT. GL7832; number average molecular weight 1079; hydroxyl value 104.0 mg KOH / g; acid value 0.81; polyester polyol obtained by dehydration condensation of neopentyl glycol and terephthalic acid, 180.2 g), 2,2-dimethylolpropionic acid (27.5 g), and 4,4'-dicyclohexylmethane diisocyanate (184.7 g) were heated in dipropylene glycol dimethyl ether (DMM, 142.3 g) in the presence of dibutyltin dilaurine (0.1512 g) under a nitrogen atmosphere at 80-85°C for 4.5 hours. The reaction mixture was cooled to 80°C, and triethylamine (20.4g) was added and mixed. Of this mixture, 392.4g was added to water (541.5g) under vigorous stirring. Then, 35% by mass of 2-methyl-1,5-pentanediamine aqueous solution (59.7g) and 35% by mass of 2-(2-aminoethylamino)ethanol (8.0g) were added to obtain aqueous polyurethane resin dispersion composition (5) (weight-average molecular weight of polyurethane resin: 690,000, acid value: 27.2).

[0120] [Manufacturing Example 6] <Production of aqueous polyurethane resin dispersion composition (6)> A polyester polyol (number average molecular weight 1000; hydroxyl value 112.2 mg KOH / g; acid value 0.04, 180.1 g) obtained by dehydration condensation of hexanediol and isophthalic acid, along with 2,2-dimethylolpropionic acid (28.7 g) and 4,4'-dicyclohexylmethane diisocyanate (192.4 g), was heated in dipropylene glycol dimethyl ether (DMM, 145.0 g) in the presence of dibutyltin dilaurine (0.1348 g) under a nitrogen atmosphere at 80-85°C for 4.5 hours. The reaction mixture was cooled to 80°C, and triethylamine (21.4 g) was added and mixed. Of this mixture, 392.5 g was added to water (539.9 g) under vigorous stirring. Next, a 35% by mass aqueous solution of 2-methyl-1,5-pentanediamine (62.7 g) and a 35% by mass 2-(2-aminoethylamino)ethanol (8.0 g) were added to create an aqueous polyurethane resin dispersion composition (6) (weight-average molecular weight of polyurethane resin: 660,000, acid value: 27.5).

[0121] [Manufacturing Example 7] <Production of aqueous polyurethane resin dispersion composition (7)> ETERNACOLL® UM90(3 / 1) (manufactured by Ube Industries; number average molecular weight 903; hydroxyl value 124.3 mg KOH / g; a polycarbonate diol obtained by reacting 1,4-cyclohexanedimethanol and 1,6-hexanediol (molar ratio 3:1) with a carbonate ester, 152.1 g), polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical; number average molecular weight 1955; hydroxyl value 57.4 mg KOH / g, 37.9 g), 2,2-dimethylolpropionic acid (29.7 g), and 4,4'-dicyclohexylmethane diisocyanate (202.8 g) were heated in dipropylene glycol dimethyl ether (DMM, 107.0 g) in the presence of dibutyltin dilaurate (0.1837 g) under a nitrogen atmosphere at 80-85°C for 5 hours. The reaction mixture was cooled to 80°C, and triethylamine (22.2g) was added and mixed. Of this mixture, 365.3g was added to water (569.6g) under vigorous stirring. Then, 35% by mass of 2-methyl-1,5-pentanediamine aqueous solution (62.2g) and 35% by mass of 2-(2-aminoethylamino)ethanol (8.0g) were added to obtain aqueous polyurethane resin dispersion composition (7) (weight-average molecular weight of polyurethane resin: 710,000, acid value: 27.0).

[0122] [Manufacturing Example 8] <Production of aqueous polyurethane resin dispersion composition (8)> ETERNACOLL® UM90(3 / 1) (manufactured by Ube Industries; number average molecular weight 903; hydroxyl value 124.3 mg KOH / g; polycarbonate diol obtained by reacting 1,4-cyclohexanedimethanol, 1,6-hexanediol (molar ratio 3:1) with a carbonate ester, 113.7 g), polytetramethylene ether glycol (PTMG, manufactured by Mitsubishi Chemical; number average molecular weight 1955; hydroxyl value 57.4 mg KOH / g, 76.0 g), 2,2-dimethylolpropionic acid (28.4 g), and 4,4'-dicyclohexylmethane diisocyanate (185.2 g) were heated in dipropylene glycol dimethyl ether (DMM, 102.0 g) in the presence of dibutyltin dilaurate (0.1323 g) under a nitrogen atmosphere at 80-85°C for 4.5 hours. The reaction mixture was cooled to 80°C, and triethylamine (21.2g) was added and mixed. Of this mixture, 365.7g was added to water (570.7g) under vigorous stirring. Then, a 35% by mass aqueous solution of 2-methyl-1,5-pentanediamine (59.7g) and a 35% by mass 2-(2-aminoethylamino)ethanol (8.0g) were added to obtain an aqueous polyurethane resin dispersion composition (8) (weight-average molecular weight of polyurethane resin: 740,000, acid value: 27.2).

[0123] [Manufacturing Example 9] <Manufacturing of aqueous polyurethane resin dispersion composition blend (9)> 0.29 g of aqueous polyurethane resin dispersion composition (4) and 4.71 g of aqueous polyurethane resin dispersion composition (5) were stirred and mixed to obtain aqueous polyurethane resin dispersion composition (9).

[0124] [Manufacturing Example 10] <Manufacturing of aqueous polyurethane resin dispersion composition blend (10)> 0.29 g of aqueous polyurethane resin dispersion composition (4) and 4.71 g of aqueous polyurethane resin dispersion composition (6) were stirred and mixed to obtain aqueous polyurethane resin dispersion composition (10).

[0125] [Examples 1-5, Comparative Examples 1-4] Using the aforementioned aqueous polyurethane resin dispersion composition or the composition thereof, coating films were prepared by the method described above, and the König hardness, adhesion to the electrodeposited layer surface, and tensile properties were measured. The results are shown in Table 1.

[0126] [Table 1]

[0127] As shown in Examples 1-5 of Table 1, the coating obtained by applying and heat-treating the aqueous urethane resin dispersion of the present invention exhibits high König hardness with low-temperature, short-time drying at 80°C for 10 minutes. By keeping the aromatic ring concentration and ether group concentration within a certain range, it is possible to improve adhesion to the electrodeposited surface and elastic modulus while maintaining high König hardness with low-temperature, short-time drying at 80°C for 10 minutes (see Examples 1-5). On the other hand, when the polyurethane resin contains no ether groups at all, the adhesion is poor (see Comparative Examples 1 and 2). Furthermore, if the polyurethane resin contains no aromatic rings at all, the elastic modulus and hardness will be lower (see Comparative Examples 3 and 4). [Industrial applicability]

[0128] The composition containing the aqueous urethane resin dispersion of the present invention can be dried at low temperatures of 100°C or less in a short time. The coating film obtained from the composition containing the aqueous urethane resin dispersion has high adhesion, flexibility, and hardness. Therefore, it is expected to contribute to reducing greenhouse gas emissions by enabling low-temperature drying of floor coatings, coatings for plastic substrates or rubber, steel plate treatment agents, and vehicle primer layers.

Claims

1. An aqueous polyurethane resin dispersion composition comprising a polyurethane resin and an aqueous medium, The polyurethane resin has constituent units derived from polyester polyol (A) composed of polyol (Aa) and dicarboxylic acid (Ab), constituent units derived from polyether polyol (G), and constituent units derived from polyisocyanate (B), and has aromatic rings in the polyurethane resin. An aqueous polyurethane resin dispersion composition having an aromatic ring content of 4% to 18% by mass and an ether bond content of 0.5% to 10% by mass in the polyurethane resin.

2. An aqueous polyurethane resin dispersion composition comprising two or more polyurethane resins and an aqueous medium, wherein at least one polyurethane resin has constituent units derived from polyester polyol (A) having polyol (Aa) and dicarboxylic acid (Ab) as constituent components and constituent units derived from polyisocyanate (B), and has aromatic rings in the polyurethane resin, and at least one polyurethane resin has constituent units derived from polyether polyol (G) and constituent units derived from polyisocyanate (B), and the content of aromatic rings in the total polyurethane resin is 4% to 18% by mass, and the content of ether bonds is 0.5% to 10% by mass.

3. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, wherein the polyurethane resin further comprises a constituent unit derived from an acidic group-containing polyol (C) and a constituent unit derived from a chain extender (E).

4. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, wherein the dicarboxylic acid (Ab) comprises an aromatic dicarboxylic acid.

5. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, having constituent units derived from polyols (F) other than the polyester polyol (A), acidic group-containing polyol, and polyether polyol (G).

6. The aqueous polyurethane resin dispersion composition according to claim 4, wherein the two carboxyl groups in the aromatic dicarboxylic acid are in a para position on the benzene ring.

7. The aqueous polyurethane resin dispersion composition according to claim 5, wherein the polyol (F) is a polycarbonate polyol.

8. The aqueous polyurethane resin dispersion composition according to claim 4, wherein the polyether polyol (G) and the polyol (F) have 2 hydroxyl groups.

9. The aqueous polyurethane resin dispersion composition according to claim 3, wherein the chain extender (E) is a polyamine.

10. The aqueous polyurethane resin dispersion composition according to claim 1, wherein the mass ratio of the polyester polyol (A) to the polyether polyol (G) is 50:50 to 90:

10.

11. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, wherein the total amount of the polyisocyanate (B) contains 50 to 100% by mass of an alicyclic polyisocyanate.

12. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, wherein the weight-average molecular weight of the polyurethane resin is 100,000 or more.

13. The aqueous polyurethane resin dispersion composition according to claim 1 or 2, wherein the hydroxyl value of the dicarboxylic acid (Ab) is 55 to 140 mg KOH / g.

14. A coating material composition comprising the aqueous polyurethane resin dispersion composition according to claim 1 or 2.

15. A coating film obtained by applying and drying the coating material composition according to claim 14.

16. The coating film according to claim 15, wherein when a cross-section peel test of the coating film obtained by drying the coating material composition at 80°C for 45 minutes is performed on the electrodeposited surface, no peeling is observed.

17. A method for producing a coating film, comprising the step of drying the coating material composition according to claim 14 at 20°C to 100°C.

18. A coating material composition according to claim 14, for use as a primer or base coat for metal exteriors.

19. A coating material composition according to claim 14 for use with fracture-resistant materials.

20. The coating material composition according to claim 15, for use as a floor coat, plastic or rubber coating, for a coating film according to claim 15.

21. A steel plate treatment agent containing the coating material composition described in claim 14.

22. A polyurethane resin having constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), constituent units derived from a polyether polyol (G), and constituent units derived from a polyisocyanate (B), and having aromatic rings in the polyurethane resin, wherein the content of aromatic rings in the polyurethane resin is 4% to 18% by mass, and the content of ether bonds is 0.5% to 10% by mass.

23. A coating film containing the polyurethane resin described in claim 22.

24. A polyurethane resin composition comprising two or more polyurethane resins, wherein at least one polyurethane resin has constituent units derived from a polyester polyol (A) composed of a polyol (Aa) and a dicarboxylic acid (Ab), and constituent units derived from a polyisocyanate (B), and has an aromatic ring in the polyurethane resin, and at least one polyurethane resin has constituent units derived from a polyether polyol (G) and constituent units derived from a polyisocyanate (B), A polyurethane resin composition in which the total polyurethane resin contains 4% to 18% by mass of aromatic rings and 0.5% to 10% by mass of ether bonds.

25. A coating film containing the polyurethane resin composition described in claim 24.

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