CN110770270B - Aqueous polyurethane dispersion, process for producing aqueous polyurethane dispersion, aqueous coating composition, and coating film - Google Patents

Abstract

An aqueous polyurethane dispersion comprising: water; and OH group-containing polyurethane which is a neutralized product of OH group-containing polyurethane having an OH group at a molecular chain end and a tertiary amine. In the above polyurethane aqueous dispersion, the OH group-containing polyurethane comprises: a structural unit (A1) derived from a predetermined polyol; a structural unit (B1) derived from a prescribed first diol; a structural unit (C1) derived from a polyvalent alcohol having a number of prescribed functional groups per molecule of more than 2 and 4 or less; and a structural unit (D1) derived from a second diol having a carboxyl group. The weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less.

Description

Aqueous polyurethane dispersion, process for producing aqueous polyurethane dispersion, aqueous coating composition, and coating film

Technical Field

The present invention relates to an aqueous polyurethane dispersion, a method for producing an aqueous polyurethane dispersion, an aqueous coating composition, and a coating film. This application is based on and claims the benefit of priority No. 2017-122609 filed in japan at 22.6.2017, the entire contents of which are incorporated herein by reference.

Background

In order to protect the interior materials of vehicles and the surfaces of audio equipment, personal computers, cellular phones, and the like, a coating film is formed by applying a paint on the surface. A method of using a solvent-based urethane resin composition or a urethane-modified acrylic resin composition as such a coating material has been proposed (for example, patent documents 1 and 2).

In addition, the surface of such a coating film may be eroded by an ultraviolet absorber contained in cosmetics, sunscreen agents, or the like. As a countermeasure against this, a method of using a polyurethane composition as the coating material is proposed (for example, patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2012-121984

Patent document 2: japanese laid-open patent publication No. 2012-97127

Patent document 3: japanese patent laid-open publication No. 2016-16906.

Disclosure of Invention

Problems to be solved by the invention

In the urethane composition for protecting the surface of the substrate as described above, the appearance is impaired by the damage generated on the surface. Therefore, it is expected to have self-repairing properties, i.e., to naturally repair the damage generated. In addition, the coating film on the surface of the substrate is also expected to have resistance to ultraviolet absorbers (ultraviolet absorber resistance). In recent years, from the viewpoint of environmental protection, an aqueous dispersion containing no organic solvent as a main component is required as the coating composition.

Accordingly, an object of the present invention is to provide an environmentally friendly aqueous polyurethane dispersion that can form a coating film having self-repairability and ultraviolet absorber resistance, a method for producing the aqueous polyurethane dispersion, an aqueous coating composition, and a coating film using the aqueous coating composition.

Means for solving the problems

The aqueous polyurethane dispersions of the present application contain: water; and a neutralized product of polyurethane containing OH groups and tertiary amine dispersed in water, the polyurethane containing OH groups having OH groups at the molecular chain terminals. The OH group-containing polyurethane contains a structural unit (a1) derived from the polyol (a), a structural unit (B1) derived from the first diol (B), a structural unit (C1) derived from the polyvalent alcohol (C), a structural unit (D1) derived from the second diol (D), and a structural unit (E1) derived from the diisocyanate component (E) in the molecular chain. The polyol (A) is at least one of a polycarbonate polyol and a polyester polyol, and has a number average molecular weight of more than 500 and not more than 5000. The first diol (B) is a diol having a number average molecular weight of 500 or less and having no carboxyl group. The polyvalent alcohol (C) is a polyvalent alcohol having a number average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less. The second diol (D) is a diol having a carboxyl group. The diisocyanate component (E) comprises xylylene diisocyanate (Ea). Further, the structural unit (E1) includes the structural unit (E1a) derived from xylylene diisocyanate (Ea). The weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less.

ADVANTAGEOUS EFFECTS OF INVENTION

The aqueous polyurethane dispersion according to the present invention can provide an environmentally friendly aqueous polyurethane dispersion that can form a coating film having self-repairability and ultraviolet absorber resistance, a method for producing the aqueous polyurethane dispersion, an aqueous coating composition, and a coating film using the aqueous polyurethane dispersion.

Drawings

Fig. 1 is a flow chart showing a typical process of a method for producing an aqueous polyurethane dispersion according to an embodiment of the present invention.

Detailed Description

[ description of embodiments of the invention of the present application ]

First, embodiments of the invention of the present application will be exemplified. The aqueous polyurethane dispersion according to the invention comprises: water; and a neutralized product of polyurethane containing OH groups and tertiary amine dispersed in water, the polyurethane containing OH groups having OH groups at the molecular chain terminals. The OH group-containing polyurethane contains a structural unit (a1) derived from the polyol (a), a structural unit (B1) derived from the first diol (B), a structural unit (C1) derived from the polyvalent alcohol (C), a structural unit (D1) derived from the second diol (D), and a structural unit (E1) derived from the diisocyanate component (E) in the molecular chain. The polyol (a) is at least one of a polycarbonate polyol and a polyester polyol, and has a number average molecular weight of more than 500 and not more than 5000. The first diol (B) is a diol having a number average molecular weight of 500 or less and having no carboxyl group. The polyvalent alcohol (C) is a polyvalent alcohol having a number average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less. The second diol (D) is a diol having a carboxyl group. The diisocyanate component (E) comprises xylylene diisocyanate (Ea). Further, the structural unit (E1) includes the structural unit (E1a) derived from xylylene diisocyanate (Ea). The weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less. By using the polyurethane aqueous dispersion, a coating film having self-repairability and ultraviolet absorber resistance can be formed. In addition, by using water as a solvent, an environmentally friendly aqueous polyurethane dispersion can be provided.

In the aqueous polyurethane dispersion, the proportion of the structural unit (a1) derived from the polyol (a) in the molecular chain of the OH group-containing polyurethane may be 10% by mass or more and 60% by mass or less in terms of mass. By this feature, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

Assuming that all OH groups contained in all polyols which are sources of the structural unit (A1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) are reacted with all NCO groups contained in diisocyanate which is a source of the structural unit (E1), and the total number of OH groups contained in a pseudo OH group-containing polyurethane molecule formed by the reaction is f, the f is an average value of f per 1000 calculated molecular weights of the pseudo OH group-containing polyurethane₁₀₀₀The value may be 2.1 or more and 2.9 or moreThe following steps. By this feature, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The acid value of the OH group-containing polyurethane may be 14 or more and 55 or less. By this feature, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The structural unit (E1) may further include a structural unit (E1b), and the structural unit (E1b) is derived from at least one diisocyanate selected from the group consisting of an aromatic diisocyanate compound other than xylylene diisocyanate (Ea), an alicyclic diisocyanate compound, and an aliphatic diisocyanate compound. This feature enables more reliable formation of a coating film having self-repairability and ultraviolet absorber resistance.

The polyol (a) may be a polycarbonate polyol mainly composed of at least one of 1, 6-hexanediol and 1, 4-cyclohexanedimethanol. The polyol (a) may be a polyester polyol mainly composed of a lactone. By this feature, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed. In the present specification, "mainly" means that the ratio is 50% by mass or more, preferably 75% by mass or more. For example, the component X mainly contains A, and 50 mass% or more of the substances constituting the component X are A. That is, 50% by mass or more of the polycarbonate polyol may be at least one of 1, 6-hexanediol and 1, 4-cyclohexanedimethanol. In addition, at least 50% by mass of the polyester polyol may be a lactone.

The structural unit derived from a polyvalent alcohol (C1) may be mainly composed of a structural unit composed of trimethylolpropane. By forming such a polyurethane aqueous dispersion, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The structural unit (B1) derived from the first diol may be mainly composed of a structural unit composed of 1, 4-cyclohexanedimethanol. By forming such a polyurethane aqueous dispersion, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The invention of the present application also relates to a process for producing the aqueous polyurethane dispersion. The production method of the present invention is a method for producing an aqueous polyurethane dispersion, comprising: a polyurethane synthesis step (1) for synthesizing an OH group-containing polyurethane having a weight-average molecular weight of 16000 or more and 140000 or less by reacting a polyol (A), a first diol (B), a polyvalent alcohol (C), a second diol (D), and a diisocyanate component (E); a neutralization step (2) for neutralizing the synthesized OH group-containing polyurethane with a neutralizing agent comprising a tertiary amine; and a production step (3) for dispersing the neutralized product formed in the neutralization step in water to produce an aqueous polyurethane dispersion in which the neutralized product is dispersed in water. By this method, an aqueous polyurethane dispersion capable of forming a coating film having self-repairability and ultraviolet absorber resistance can be provided.

In the polyurethane synthesis step (1), the proportion of the structural unit (a1) derived from the polyol (a) in the entire OH group-containing polyurethane synthesized in the polyurethane synthesis step (1) may be 10 mass% or more and 60 mass% or less in terms of mass ratio. As described above, by adjusting the proportion of the structural unit (a1), a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

In the polyurethane synthesis step (1), when it is assumed that all OH groups contained in all polyols that are the sources of the structural unit (a1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) react with all NCO groups contained in diisocyanate that is the source of the structural unit (E1), and the total number of OH groups contained in a pseudo OH group-containing polyurethane molecule formed by the reaction is defined as a f value, the f value that is the average value of the f values per 1000 calculated molecular weights of the pseudo OH group-containing polyurethane is f₁₀₀₀The value may be 2.1 or more and 2.9 or less. By making adjustments so that f is above₁₀₀₀When the value is within the above range, the reaction proceeds, and a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

In the polyurethane synthesis step (1), the reaction may be carried out so that the acid value of the OH group-containing polyurethane is 14 or more and 55 or less. By adjusting the acid value in this manner, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The diisocyanate component (E) may further contain, in addition to the xylylene diisocyanate (Ea), at least one diisocyanate (Eb) selected from the group consisting of aromatic diisocyanate compounds other than the xylylene diisocyanate (Ea), alicyclic diisocyanate compounds and aliphatic diisocyanate compounds. By further containing diisocyanate (Eb), an aqueous polyurethane dispersion capable of more reliably forming a coating film having self-repairability and ultraviolet absorber resistance can be provided more reliably.

The invention of the present application further relates to a water-based coating composition comprising the above aqueous polyurethane dispersion as a first dispersion; and at least one dispersion of a carbodiimide crosslinking agent aqueous dispersion and a polyisocyanate crosslinking agent dispersion as a second dispersion, the carbodiimide crosslinking agent aqueous dispersion containing a carbodiimide group of 150 equivalents or more and 600 equivalents or less as a nonvolatile component; the polyisocyanate crosslinking agent dispersion contains 5 to 25 mass% of isocyanate groups as nonvolatile components in terms of mass. By using such an aqueous coating composition, a coating film having self-repairability and ultraviolet absorber resistance can be formed.

The water-based coating composition may be a multi-liquid coating composition comprising a first liquid containing an aqueous polyurethane dispersion and a second liquid containing at least one dispersion of an aqueous dispersion of a carbodiimide crosslinking agent and a dispersion of a polyisocyanate crosslinking agent. By using such a multi-liquid type coating composition, coating can be performed more easily and reliably.

In the above-mentioned water-based coating composition, the equivalent ratio N ═ C ═ N/COOH of the carbodiimide group (N ═ C ═ N group) in the carbodiimide crosslinking agent contained in the aqueous dispersion of the carbodiimide crosslinking agent and the carboxyl group (COOH group) in the OH group-containing polyurethane contained in the aqueous dispersion of polyurethane may be 0.30 or more and 1.7 or less. By using such an aqueous coating composition, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

In the above-mentioned water-based coating composition, the equivalent ratio NCO/OH ratio of the isocyanate group (NCO) in the polyisocyanate crosslinking agent contained in the polyisocyanate crosslinking agent dispersion to the OH group in the OH group-containing polyurethane contained in the polyurethane water dispersion may be 0.30 or more and 2.5 or less. By using such an aqueous coating composition, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The present invention also relates to a coating film formed by applying the aqueous polyurethane dispersion or the aqueous coating composition to a substrate. The coating film has self-repairability and ultraviolet absorber resistance.

[ details of the embodiments of the invention of the present application ]

The following describes the embodiments of the present invention in detail. An aqueous polyurethane dispersion according to an embodiment of the present invention contains: water; and a neutralized product of polyurethane containing OH groups and tertiary amine dispersed in water, the polyurethane containing OH groups having OH groups at the molecular chain terminals. The OH group-containing polyurethane contains a structural unit (a1) derived from the polyol (a), a structural unit (B1) derived from the first diol (B), a structural unit (C1) derived from the polyvalent alcohol (C), a structural unit (D1) derived from the second diol (D), and a structural unit (E1) derived from the diisocyanate component (E) in the molecular chain. The polyol (A) is at least one of a polycarbonate polyol and a polyester polyol, and has a number average molecular weight of more than 500 and not more than 5000. The first diol (B) is a diol having a number average molecular weight of 500 or less and having no carboxyl group. The polyvalent alcohol (C) is a polyvalent alcohol having a number average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less. The second diol (D) is a diol having a carboxyl group. The diisocyanate component (E) comprises xylylene diisocyanate (Ea). Further, the structural unit (E1) includes the structural unit (E1a) derived from xylylene diisocyanate (Ea). The weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less.

The aqueous polyurethane dispersion is a dispersion or emulsion obtained by dispersing a neutralized product obtained by neutralizing the above-mentioned polyurethane containing OH groups in water. By adopting such a configuration, the surface protective agent having self-repairability and ultraviolet absorber resistance and serving as a substrate and a case can be sufficiently exhibited.

The aqueous polyurethane dispersion according to an embodiment of the present invention is a so-called aqueous polyurethane dispersion. Therefore, the environmental load can be reduced as compared with an organic solvent-based polyurethane dispersion.

Next, the structure of the OH group-containing polyurethane will be described. The OH group-containing polyurethane is a neutralized product of OH group-containing polyurethane and tertiary amine. The OH group-containing polyurethane contains in the molecular chain: a structural unit (A1) derived from a polyol which is at least one of a polycarbonate polyol and a polyester polyol and has a number average molecular weight of more than 500 and not more than 5000; a structural unit (B1) derived from a first diol having a number average molecular weight of 500 or less and having no carboxyl group; a structural unit (C1) derived from a polyvalent alcohol having a number average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less; a structural unit (D1) from a second diol having a carboxyl group; and a structural unit derived from a diisocyanate (E1).

[ structural Unit (A1) ]

The OH group-containing polyurethane contains a structural unit (A1) derived from the polyol (A) in the molecular chain. The polyol (a) is at least one of a polycarbonate polyol and a polyester polyol, and has a number average molecular weight of more than 500 and not more than 5000.

The structural unit (a1) is formed from a polyol (a) which is at least one of a polycarbonate polyol and a polyester polyol and has a number average molecular weight of more than 500 and not more than 5000. The structural unit derived from the polycarbonate polyol and the structural unit derived from the polyester polyol are formed by using the polycarbonate polyol having the number average molecular weight and the polyester polyol having the number average molecular weight as raw materials, respectively.

The polycarbonate polyol is obtained by subjecting a polyol compound and a carbonate compound to, for example, dealcoholization or dephenolization.

The polyol compound that can be used for the synthesis of the polycarbonate polyol is not particularly limited, and examples thereof include: ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 8-octanediol, 1, 9-nonanediol, diethylene glycol, dipropylene glycol, 1, 4-cyclohexanedimethanol, an ethylene oxide adduct of bisphenol a, a propylene oxide adduct of bisphenol a, a diol such as sorbitol cyclo-diol, and a polyvalent alcohol such as trimethylolpropane, glycerol, and pentaerythritol. One kind of the polyhydric alcohol compound may be used alone, or two or more kinds may be used in combination. Among these, a polycarbonate polyol mainly composed of at least one of 1, 6-hexanediol and 1, 4-cyclohexanedimethanol is preferably used. By using one or both of 1, 4-cyclohexanedimethanol and 1, 6-hexanediol alone, an aqueous polyurethane dispersion which can form a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

Examples of the carbonate-based compound used for the synthesis of the polycarbonate polyol include: ethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and the like. The carbonate-based compound may be used alone or in combination of two or more.

The polyester polyol is obtained by copolymerization or polycondensation reaction of a carboxylic acid component with a diol and/or a polyvalent alcohol used for synthesis of the polycarbonate polyol. The polyester polyol may be mainly composed of lactone. In particular, by using a polyester polyol mainly containing lactone, a polyurethane aqueous dispersion capable of forming a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed.

The structural unit (a1) can be formed by copolymerization of, for example, a polyester polyol. The polyester polyol can be obtained by copolymerization of: for example, at least one of the diols and polyvalent alcohols described above as substances that can be used for the synthesis of the polycarbonate polyol; dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, isophthalic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, citric acid, itaconic acid, glutamic acid, and 1, 4-cyclohexanedicarboxylic acid; or oils and fats such as castor oil.

The structural unit (a1) can also be formed by, for example, a polycondensation reaction of a lactone polyol. For example, the constituent unit (A1) can also be obtained by polycondensation reaction of a diol used for synthesis of a polycarbonate polyol and a lactone such as e-caprolactone, delta-valerolactone or 3-methyl-delta-valerolactone. Among them, epsilon-caprolactone is particularly preferably used.

The structural unit (A1) constituting the OH group-containing polyurethane is a unit constituting a molecular chain and is derived from a polyol (A) which is at least one of a polycarbonate polyol and a polyester polyol and has a number average molecular weight of more than 500 and not more than 5000. By setting the number average molecular weight as described above, a coating film having more excellent self-repairability and ultraviolet absorber resistance can be formed more reliably.

[ structural Unit (B1) ]

The OH group-containing polyurethane contains a structural unit (B1) derived from the first diol (B) in the molecular chain. The first diol (B) is a diol having a number average molecular weight of 500 or less and having no carboxyl group. That is, the structural unit (B1) is a structural unit that does not overlap with the structural unit (a 1).

Examples of the structural unit (B1) derived from the first diol include structural units derived from a diol (B) which has no carboxyl group and is described above as a compound of a polyol which can be used for the synthesis of a polycarbonate polyol. Among them, the diol (B) includes, in particular: 1, 4-butanediol, 1, 6-hexanediol, 1, 4-cyclohexanedimethanol, and the like. Among these, the structural unit derived from the first diol (B1) preferably mainly comprises a structural unit composed of 1, 4-cyclohexanedimethanol.

The diol (B) has a number average molecular weight of 500 or less. Thus, a coating film having excellent self-repairability and ultraviolet absorber resistance can be formed. In addition, sufficient hardness can be imparted to the coating film.

[ structural Unit (C1)

The OH group-containing polyurethane contains a structural unit (C1) derived from a polyvalent alcohol (C) in the molecular chain. The polyvalent alcohol (C) is a polyvalent alcohol having a number average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less. That is, the structural unit (C1) is a structural unit that does not overlap with the structural unit (a1) and the structural unit (B1).

The polyvalent alcohol (C) is not particularly limited, and examples thereof include: trivalent alcohols such as glycerin and trimethylolpropane, tetravalent alcohols such as tetramethylolmethane (pentaerythritol) and diglycerin, PO and/or EO adducts of the trivalent alcohols and the tetravalent alcohols, castor oil, and the like. Among these, the structural unit derived from a polyvalent alcohol (C1) is preferably mainly composed of a structural unit composed of trimethylolpropane.

The number average molecular weight of the polyvalent alcohol compound (C) is 500 or less, and the number of functional groups per molecule exceeds 2 and is 4 or less. With this structure, a coating film having an improved crosslinking density and further excellent self-repairability and ultraviolet absorber resistance can be formed. In addition, the aqueous polyurethane dispersion can provide high transparency by improving the solubility.

[ structural Unit (D1) ]

The OH group-containing polyurethane contains a structural unit (D1) derived from a second diol (D) having a carboxyl group in the molecular chain. That is, the structural unit (D1) is a structural unit that does not overlap with the structural unit (B1) and the structural unit (C1).

The second diol (D) having a carboxyl group, which is a source of the structural unit (D1), is not particularly limited, and examples thereof include: dimethylolalkanoic acids such as 2, 2-dimethylolpropionic acid and 2, 2-dimethylolbutyric acid, N-dihydroxyethylglycine, N-dihydroxyethylalanine, 3, 4-dihydroxybutanesulfonic acid, 3, 6-dihydroxy-2-toluenesulfonic acid, polyether polyols containing acidic groups, polyester polyols containing acidic groups, and the like. Of the above, dimethylol alkanoic acids are preferred, and 2, 2-dimethylol propionic acid and 2, 2-dimethylol butyric acid are more preferred. These may be used alone or in combination of two or more.

[ structural Unit (E1) ]

The OH group-containing polyurethane contains a structural unit (E1) derived from a diisocyanate component (E) in the molecular chain. The diisocyanate component (E) comprises xylylene diisocyanate (Ea). Further, the structural unit (E1) includes the structural unit (E1a) derived from xylylene diisocyanate (Ea).

The structural unit (E1a) derived from xylylene diisocyanate (Ea) is formed by using xylylene diisocyanate (Ea) as a raw material. Xylylene diisocyanate (Ea) is one of aromatic diisocyanates. In the present invention, by having a structural unit (E1a) derived from xylylene diisocyanate (Ea), it is possible to provide an aqueous polyurethane dispersion which can form a coating film having further improved ultraviolet absorber resistance.

The structural unit (E1) derived from the diisocyanate may further include a structural unit (E1b) derived from a diisocyanate (Eb) which is at least one selected from the group consisting of an aromatic diisocyanate compound other than xylylene diisocyanate (Ea), an alicyclic diisocyanate compound and an aliphatic diisocyanate compound. The structural unit (E1b) is formed by using, as a raw material, at least one diisocyanate (Eb) selected from the group consisting of an aromatic diisocyanate compound other than xylylene diisocyanate (Ea), an alicyclic diisocyanate compound, and an aliphatic diisocyanate compound.

The aromatic cyclic diisocyanate is not particularly limited, and examples thereof include: diphenylmethane diisocyanate (MDI), 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, xylene-1, 4-diisocyanate, xylene-1, 3-diisocyanate, tetramethylxylylene diisocyanate, m-phenylene diisocyanate, o-phenylene diisocyanate, and the like.

The alicyclic diisocyanate is not particularly limited, and examples thereof include: isophorone diisocyanate, 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, cyclohexyl diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, dicyclohexylmethane diisocyanate, bis (4-isocyanatocyclohexyl) methane, 1, 3-diisocyanatomethylcyclohexane, 1, 4-diisocyanatomethylcyclohexane, norbornane diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetramethyl xylene diisocyanate and the like.

The aliphatic diisocyanate is not particularly limited, and examples thereof include: hexamethylene diisocyanate, tetramethylene diisocyanate, 1, 5-pentamethylene diisocyanate, trimethylhexamethylene diisocyanate, 2-methyl-pentane-1, 5-diisocyanate, 3-methyl-pentane-1, 5-diisocyanate, dicyclohexylmethane-4, 4' -diisocyanate, lysine isocyanate, ethylene oxide diisocyanate, norbornene diisocyanate, and the like.

[ Tertiary amines ]

The aqueous polyurethane dispersion of the present embodiment contains a neutralized product of polyurethane containing an OH group and a tertiary amine dispersed in water. The tertiary amines can act as neutralizing agents for polyurethanes containing OH groups.

The above-mentioned tertiary amine compound used for neutralizing the OH group-containing polyurethane is not particularly limited, and there may be mentioned: trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, dimethylethanolamine, diethylethanolamine, N-methylmorpholine, pyridine, and the like. Among them, dimethylethanolamine and triethylamine are preferable. These may be used alone or in combination of two or more.

[ aqueous polyurethane Dispersion ]

The aqueous polyurethane dispersion of the present embodiment contains: water; and a neutralized product of polyurethane containing OH groups and tertiary amine dispersed in water. The OH group-containing polyurethane has OH groups at the molecular chain terminals. The amount of the neutralized product, the amount of water as a dispersion medium and the ratio thereof are not particularly limited, and the amount and the ratio required for sufficiently dispersing the OH group-containing polyurethane may be appropriately selected.

[ OH group-containing polyurethane ]

As described above, the OH group-containing polyurethane contained in the aqueous polyurethane dispersion of the present embodiment includes the structural unit (a1), the structural unit (B1), the structural unit (C1), the structural unit (D1), and the structural unit (E1).

In the OH group-containing polyurethane, the proportion of the structural unit (a1) derived from the polyol in the molecular chain of the OH group-containing polyurethane is preferably 10 mass% or more and 60 mass% or less in terms of mass. Such a ratio can be achieved by setting the mass ratio of the polyol (a) of at least either one of the polycarbonate polyol and the polyester polyol, which is the source of the structural unit (a1), to 10 mass% or more and 60 mass% or less in the entire OH group-containing polyurethane. By setting the above ratio to 10% by mass or more and 60% by mass or less, it is possible to more reliably provide an aqueous polyurethane dispersion which can form a coating film exhibiting self-repairability and ultraviolet absorber resistance.

When it is assumed that all OH groups contained in all polyols from which the structural unit (a1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) are derived react with all NCO groups contained in diisocyanate from which the structural unit (E1) is derived, and the total number of OH groups contained in a pseudo OH group-containing polyurethane molecule formed by the reaction is represented by f, it is preferable that f is an average value of f values per 1000 calculated molecular weights of the pseudo OH group-containing polyurethane₁₀₀₀The value is 2.1 or more and 2.9 or less.

The above f will be shown below₁₀₀₀An example of the method for solving the value of (c) is described (the method for solving (c) is not limited to this method).

First, the calculated molecular weight was calculated.

The total x coefficient n of the molecular weight ═ [ (molecular weight of each raw material) × (mol number of each raw material) ] was calculated

The coefficient n is obtained as follows. For example, it is assumed that an OH raw material reacts with an NCO raw material to form OH-terminated polyurethane. When the raw material has a valence of 2 or more, a polyol of [ (xmol) +1mol ] is inevitably synthesized with respect to the polyisocyanate (xmol). The coefficient n is thus determined.

The coefficient n is 1/{ (total of mol numbers of polyols) - (total of mol numbers of polyisocyanates) }

Subsequently, the f value is obtained. The value f represents the total number of OH groups contained in a virtual OH group-containing polyurethane molecule formed by the reaction of all OH groups contained in all polyols that are the sources of the structural unit (a1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) with all NCO groups contained in diisocyanate that is the source of the structural unit (E1). The f-number is calculated as the average of the calculated molecular weights per unit.

The above f value is given by

Formula Mn (calculated molecular weight) 56.11/hydroxyl value x f x 1000

The value of f is derived as (Mn. times. hydroxyl value)/(56.11. times.1,000)

(56.11 is the molecular weight of potassium hydroxide).

Next, the average value f per 1000 calculated molecular weights was calculated₁₀₀₀。

f₁₀₀₀{ (f-2) × (1000/calculated molecular weight) } +2

That is, assuming that both terminals of the OH group-containing polyurethane molecule are OH groups, a part other than the OH groups at both terminals is cut out from the OH group-containing polyurethane, the cut-out part is linked to the OH groups at both terminals to prepare a molecular model having a calculated molecular weight of 1000, f₁₀₀₀The value is a standard for the average of the total number of OH groups of the OH-containing polyurethane in this case.

The average value f is shown below₁₀₀₀An example of the calculation method of (3).

When etrnacoll UC100 (polycarbonate diol) (manufactured by yunnan corporation) 0.46(mol) × 1,000(Mn) ═ 460 as component (a), 1,4-CHD (1, 4-cyclohexanedimethanol) (manufactured by eastman chemical company) 2.3(mol) × 144(Mn) × 331.2 as component (B), TMP (trimethylolpropane) (manufactured by aifeny japan) 0.4(mol) × 134(Mn) ═ 53.6 as component (C), DMPA (dimethylolpropionic acid) (manufactured by permtop corporation) 1.0(mol) × 134 as component (D), Takenate500 (xylylene diisocyanate) (manufactured by mitsui chemical corporation) 2.0(mol) × 376.4 as component (188.0 (mol) × 376.4) and HDI (hexamethylene diisocyanate) (manufactured by eastern chemical company) 2.168 (egia) × 2.38) (eesoga) (336.4),

the total of [ (molecular weight of each raw material) × (mol number of each raw material) ] is 1691.6

The coefficient n is 1/{ (a) (mol) + (B) (mol) + (C) (mol) + (D) (mol) - (Ea) (mol) - (Eb) (mol) } 1/0.16 is 6.25

Calculated molecular weight 1691.6 × 6.25-10572.5

Hydroxyl value 56.11X 0.72X 1000/1691.6 23.88

f value is 4.50

Average f value of f values per 1,000 calculated molecular weights₁₀₀₀＝2.24。

In the present embodiment, it is preferable that the acid value of the OH group-containing polyurethane is 14 or more and 55 or less. By adjusting the acid value to the above range, the OH group-containing polyurethane can be more reliably synthesized.

The weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less. By adopting the above-specified range, excellent adhesion can be obtained by improving the glossiness and the wettability to the base material such as plastic. By forming a coating film using a polyurethane aqueous dispersion composed of the OH group-containing polyurethane composition and an aqueous composition containing the polyurethane aqueous dispersion, a coating film having excellent self-repairability and durability against an ultraviolet absorber contained in cosmetics, sunscreen agents, and the like can be obtained.

As such a polyurethane aqueous dispersion, a polyurethane aqueous dispersion which can reduce environmental load and can form a coating film having self-repairability and ultraviolet absorber resistance can be obtained. Further, according to the aqueous polyurethane dispersion of the present embodiment, a coating film excellent in appearance and adhesion to a substrate can be formed.

[ Water-based coating composition ]

Next, the structure of the aqueous coating composition according to one embodiment of the present invention will be described. The aqueous coating composition of the present embodiment comprises the above-mentioned polyurethane aqueous dispersion as a first dispersion, and at least one dispersion of a carbodiimide cross-linking agent aqueous dispersion and a polyisocyanate cross-linking agent aqueous dispersion as a second dispersion, the carbodiimide cross-linking agent aqueous dispersion containing a carbodiimide group of 150 equivalents or more and 600 equivalents or less as a nonvolatile component; the polyisocyanate crosslinking agent dispersion contains 5 to 25 mass% of isocyanate groups as nonvolatile components in terms of mass. By using such an aqueous coating composition, a multi-liquid coating composition capable of forming a coating film having self-repairability and ultraviolet absorber resistance can be provided.

The aqueous coating composition of the present embodiment can also be a multi-liquid coating composition containing a first liquid containing the aqueous polyurethane dispersion and a second liquid containing at least one dispersion of an aqueous dispersion of a carbodiimide crosslinking agent and a dispersion of a polyisocyanate crosslinking agent. By making such a multi-liquid type coating composition, coating can be performed more easily and reliably.

The second liquid may contain a liquid containing a carbodiimide dispersion, and the equivalent ratio N ═ C ═ N/COOH of the content of carbodiimide groups (N ═ C ═ N groups) in the carbodiimide dispersion to the carboxyl groups (COOH groups) in the aqueous polyurethane dispersion may be 0.30 or more and 1.7 or less. The water-based coating composition can form a coating film having more excellent self-repairability and ultraviolet absorber resistance.

The second liquid may contain a liquid containing a polyisocyanate dispersion, and the equivalent ratio NCO/OH ratio of the content of isocyanate groups (NCO) in the liquid containing a polyisocyanate dispersion to OH groups (OH groups) in the aqueous polyurethane dispersion may be 0.30 or more and 2.5 or less. The water-based coating composition can form a coating film having more excellent self-repairability and ultraviolet absorber resistance.

[ Process for producing aqueous polyurethane Dispersion ]

Next, a method for producing an aqueous polyurethane dispersion according to an embodiment of the present invention will be described. The method for producing the aqueous polyurethane dispersion of the present embodiment includes a polyurethane synthesis step (1), a neutralization step (2), and a production step (3). Fig. 1 is a flow chart showing a typical process of a method for producing an aqueous polyurethane dispersion according to an embodiment of the present invention.

Referring to fig. 1, first, as a preparation step, the first glycol and the like described above are prepared (S11). That is, a polyol (a) which is at least one of a polycarbonate polyol and a polyester polyol and has a number average molecular weight of more than 500 and not more than 5000, a first diol (B), a polyvalent alcohol (C), a second diol (D), and a diisocyanate component (E) are prepared; the first diol (B) has a number average molecular weight of 500 or less and has no carboxyl group; the number average molecular weight of the polyvalent alcohol (C) is 500 or less and the number of functional groups per molecule exceeds 2 and is 4 or less; the second diol (D) has a carboxyl group; the diisocyanate component (E) comprises xylylene diisocyanate (Ea).

Next, a polyurethane synthesis step (1) of synthesizing OH group-containing polyurethane is performed (S12). In the polyurethane synthesis step (1), the polyol (a), the first diol (B), the polyvalent alcohol (C), the second diol (D), and the diisocyanate component (E) are reacted to synthesize OH group-containing polyurethane having OH groups at the molecular chain terminals. In the polyurethane synthesis step (1), an OH group-containing polyurethane having a weight average molecular weight of 16000 or more and 140000 or less is synthesized. The above reaction may be carried out so that the proportion of the structural unit (a1) derived from the polyol (a) in the entire OH group-containing polyurethane synthesized is 10 mass% or more and 60 mass% or less in terms of mass ratio, or so that the acid value of the OH group-containing polyurethane becomes 14 or more and 55 or less. In this step, the diisocyanate component (E) and the other polyol components (a) to (D) are reacted separately. The order of the reaction is not particularly limited, and for example, the reaction can be carried out in stages, that is, first, the component (A) and the component (E) are reacted, and then, the component (B), the component (C) and the component (D) are added to carry out chain extension, thereby synthesizing the desired OH group-containing polyurethane.

The above-mentioned OH group-containing polyurethane can be synthesized in a solvent. The solvent is not particularly limited as long as it is a hydrophilic solvent that does not substantially react with an isocyanate group. For example, there may be mentioned: ketones such as acetone and ethyl methyl ketone, esters, ethers such as tetrahydrofuran and N-methylmorpholine, and amides such as 3-methoxy-N, N-dimethylpropane amide, dimethylformamide, N-methylpyrrolidone and N-ethylpyrrolidone. These may be used alone or in combination of two or more.

The amount of the solvent to be added is not particularly limited, but is preferably 10 to 150% by mass based on 100 parts by mass of the solid content of the OH group-containing polyurethane.

In addition, the reaction can be carried out in the presence of a catalyst. The kind of the catalyst is not particularly limited, and for example, there may be mentioned: tin-based catalysts (e.g., trimethyltin laurate and dibutyltin dilaurate), Li-based catalysts, metal catalysts such as Bi-based catalysts, amine-based catalysts (e.g., triethylamine, N-ethylmorpholine, and triethyldiamine), and diazabicycloundecene-based catalysts. Among them, from the viewpoint of reactivity and reduction of environmental load, it is preferable to use a Li-based/Bi-based metal catalyst in combination.

Subsequently, a neutralization step (2) of neutralizing the synthesized OH group-containing polyurethane with a neutralizing agent composed of a tertiary amine is performed to form a neutralized product (S13). The OH group-containing polyurethane synthesized in the polyurethane synthesis step (1) is neutralized with a tertiary amine, more specifically, COOH groups (carboxyl groups) contained in the OH group-containing polyurethane are neutralized. The amount of the tertiary amine to be added is appropriately determined in consideration of the amount of COOH groups contained in the OH group-containing polyurethane before neutralization.

Next, an aqueous polyurethane dispersion in which the neutralized product neutralized in the neutralization step (2) is dispersed in water is prepared (S14). The method for producing such an aqueous polyurethane dispersion is not particularly limited, and for example, an aqueous polyurethane dispersion can be produced by charging a container with water, and dispersing the neutralized product obtained in steps S11 to S13 in water using a stirrer, a homogenizer, or the like. Further, the dispersion is not limited to the case of obtaining a neutralized product and then dispersing it in water, and it is also possible to disperse the OH group-containing polyurethane while neutralizing it. Therefore, the steps S13 and S14 may not be completely separated, but at least a part of the steps may be shared. For example, it is also possible to prepare an aqueous polyurethane dispersion by phase inversion emulsification or forced emulsification of an OH group-containing polyurethane using water to which a tertiary amine is added.

In the OH group-containing polyurethane synthesized in the polyurethane synthesis step (1), assuming that all OH groups contained in all polyols from which the structural unit (a1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) are derived are reacted with all NCO groups contained in diisocyanate from which the structural unit (E1) is derived, and the total number of OH groups contained in the pseudo OH group-containing polyurethane molecule formed by the reaction is set to f, the pseudo OH group-containing polyurethane molecule is assumed to have a value of fF is the average value of the f values per 1000 calculated molecular weights of OH-based polyurethanes₁₀₀₀The value may be 2.1 or more and 2.9 or less.

According to the method for producing a polyurethane aqueous dispersion, a polyurethane aqueous dispersion which can reduce environmental load and can form a coating film having self-repairability and ultraviolet absorber resistance can be easily produced. Further, the coating film obtained from the aqueous polyurethane dispersion formed by the method for producing an aqueous polyurethane dispersion according to the present embodiment is also excellent in appearance and adhesion to a substrate.

[ coating film ]

A coating film can be formed from the aqueous polyurethane dispersion or the aqueous coating composition. A coating film is formed by applying an aqueous polyurethane dispersion or an aqueous coating composition to a predetermined substrate, and drying and curing the composition as necessary. The coating film has self-repairability and ultraviolet absorber resistance.

[ use ]

The aqueous polyurethane dispersion or the water-based coating composition can be used as a surface protective material for various substrates. For example, the aqueous polyurethane dispersion or the aqueous coating composition is applied to a substrate to form a coating film for protecting the surface of interior materials of vehicles, audio equipment, personal computers, cellular phones, and the like, and thus can be used as a surface protective material having self-repairability and ultraviolet absorber resistance.

Examples

The present invention will be described in detail with reference to examples. It should be noted that the scope of the present invention is not to be interpreted restrictively by the description of these examples.

In examples 1 to 40 and comparative examples 1 to 7, aqueous polyurethane dispersions were prepared based on the mixing ratios shown in tables 1 to 16 below. Hereinafter, "parts" herein means parts by mass. The unit of the blending ratio shown in tables 1 to 16 is mass% unless otherwise specified. In tables 1 to 16, the description of example 1 and the like is repeated a plurality of times from the viewpoint of easy understanding.

The weight average molecular weight of the OH group-containing polyurethane obtained in the polyurethane synthesis step (1) was measured as follows.

Measurement apparatus GPC Shodex GPC-101 column LF804, styrene conversion

Sample concentration 0.2 vol%, THF dilution

(example 1)

In a reactor, 0.5 parts of JPP100 (tetraphenyl dipropylene glycol diphosphite) (manufactured by Nbei chemical Co., Ltd.) as a phosphite antioxidant and 135.56 parts of ETERNACOLL UC100 (polycarbonate diol) (manufactured by UK.K.) as a component (A) were dissolved in KJCMPA-100 (3-methoxy-NN-dimethylpropane amide) (manufactured by KJ Chemicals) as a solvent, 0.004 parts of Borchi Kat 0243 (metal catalyst) (manufactured by Borchers) as a catalyst were charged, the mixture was dissolved with stirring, 110.92 parts of Takenate500 (xylylene diisocyanate) (manufactured by Mitsui chemical Co., Ltd.) as a component (Ea) was added, 99.14 parts of HDI (hexamethylene diisocyanate) (manufactured by Tosoh corporation) as the component (Eb) were reacted at 85 ℃ for 2 hours. Subsequently, after cooling to 60 ℃, 39.49 parts of DMPA (dimethylolpropionic acid) (Perstrop corporation) as the component (D), 97.6 parts of 1,4-CHD (1,4 cyclohexanedimethanol) (Istman chemical Co., Ltd.) as the component (B), 15.8 parts of TMP (trimethylolpropane) (Ainfei Japan Co., Ltd.) and 213.68 parts of MEK (methyl ethyl ketone) (Kyoho Co., Ltd.) as the component (C) were added, and they were sufficiently stirred and dissolved, and BorchiKat 02430.032 parts as a catalyst were added and reacted at 80 ℃ for 5 hours. Herein, the reaction is carried out until the isocyanate value (the mass content of the remaining isocyanate group relative to the solid content) becomes 0.01% or less, thereby obtaining polyurethane having an OH group at the terminal. To this polyurethane were added 0.5 parts of TINUVIN 234 (phenyl, 2- (2H-benzotriazol-2-yl) -4, 6-bis (1-methyl-1-phenylethyl)) (manufactured by BASF), 0.5 parts of TINUVIN 770 (bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate) (manufactured by BASF) and 230.77 parts of MEK, and the mixture was thoroughly stirred and dissolved and cooled to 50 ℃. Then, 26.27 parts of DMEA (N, N-dimethylethanolamine) (manufactured by japan emulsifier co., ltd.) was added to neutralize the mixture, and 973.73 parts of water was added to perform phase inversion emulsification. The obtained emulsion was desolventized to obtain an aqueous polyurethane dispersion of example 1, which contained polyurethane having a terminal OH group and a nonvolatile content of 30%, an acid value of 33.17, a hydroxyl value of 23.88, and a pH of 8.6.

Next, an aqueous coating composition was prepared using the obtained aqueous polyurethane dispersion. The mating is as follows. To 100 parts of a polyurethane aqueous dispersion (referred to as "EM resin" in the table) having 30% of nonvolatile components, 0.1 part of TEGO FOAMEX 800 (polyoxyethylene stearyl ether, referred to as "TEG 800" in the table) (manufactured by EVONIK corporation) as an antifoaming agent, 0.15 part of BYK-3455 (polyether-modified polydimethylsiloxane) (manufactured by bike chemical corporation) as a leveling agent, and Carbodilite V02 (carbodiimide, nonvolatile component 40%, carbodiimide equivalent 590) (manufactured by japanese koku corporation) as a crosslinking agent were added in the amounts specified in table 1, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 (urethane series) (manufactured by ADEKA corporation) as a thickening agent and defoamed to prepare an aqueous coating composition of example 1.

(example 2)

The aqueous polyurethane dispersion of example 2 was obtained by the same procedure as in example 1 except that HDI as the (Eb) component was not contained and Takenate500 as the (Ea) component was contained in the formulation shown in table 1. In addition, the water-based coating composition of example 2 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 1 in the same manner as in example 1.

(example 3)

The aqueous polyurethane dispersion of example 3 was obtained by using Lupranate MI (2,4 '/4, 4' -diphenylmethane diisocyanate) (manufactured by BASF) as the component (Eb) in place of HDI, and adding Takenate500 as the component (Ea) as shown in table 1, and performing the same procedure as in example 1. In addition, the water-based coating composition of example 3 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 1 in the same manner as in example 1.

(example 4)

An aqueous polyurethane dispersion of example 4 was obtained by using Desmodur I (isophorone diisocyanate) (manufactured by Bayer corporation) as the component (Eb) in place of HDI, and incorporating Takenate500 or the like as the component (Ea) as shown in table 1 through the same procedure as in example 1. In addition, the water-based coating composition of example 4 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 1 in the same manner as in example 1.

Comparative example 1

Aqueous polyurethane dispersions of comparative example 1 were obtained by the same procedure as in example 1 except that Takenate500 as component (Ea) was not included and Lupranate MI and the like were contained as component (Eb) in the formulation shown in Table 2. In addition, the water-based coating composition of comparative example 1 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 2 in the same manner as in example 1.

Comparative example 2

Takenate500 as the (Ea) component was not included, and Desmodur I and the like were contained as the (Eb) component in the formulation shown in Table 2, and the aqueous polyurethane dispersion of comparative example 2 was obtained by the same procedure as in example 1. In addition, the water-based coating composition of comparative example 2 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 2 in the same manner as in example 1.

Comparative example 3

Takenate500 as the (Ea) component was not included, and Desmodur W (4, 4' -dicyclohexylmethane diisocyanate) (manufactured by Bayer) and the like were contained as the (Eb) component in the formulation shown in Table 2, and the same steps as in example 1 were performed. However, in the polyurethane synthesis step (1), NCO does not disappear, and a stable aqueous polyurethane dispersion cannot be obtained.

(example 5)

The aqueous polyurethane dispersion of example 5 was obtained by the same procedure as in example 1, except that eteernaoll UM (3/1) (manufactured by yu kenco ltd.) was used in place of eteernaoll UC100 as the component (a) and that eteernaoll UM (3/1) was contained in the formulation shown in table 3. In addition, the water-based coating composition of example 5 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 3 in the same manner as in example 1. ETERNACOLLUM (3/1) is a polycarbonate diol having UC 1001, 4-CHD/1,6-HD 3/1mol ratio (1, 6-HD: 1, 6-hexanediol (manufactured by Utsu Kyoho Co., Ltd)) to 1,4-CHD polycarbonate diol ETERNACOLL.

(example 6)

The aqueous polyurethane dispersion of example 6 was obtained according to the same formulation as in example 5. The water-based coating compositions of example 6 were prepared in the same manner as in example 1 and with the formulation shown in table 3, using Carbodilite V10 (carbodiimide, nonvolatile content 40%, carbodiimide equivalent 410) (manufactured by nippon chemical) instead of Carbodilite V02.

(example 7)

In contrast to example 1, an aqueous polyurethane dispersion of example 7 was obtained by the same procedure as in example 1, except that etaernacollum (1/1) (manufactured by yutonghe corporation) was used in place of etaernacollum 100 corresponding to component (a), and etaernacollum (1/1) was contained in the formulation shown in table 4. In addition, the water-based coating composition of example 7 was prepared from the obtained polyurethane aqueous dispersion by using Carbodilite V10 in place of Carbodilite V02 in the same manner as in example 1 according to the compounding shown in table 4. It is noted that eteernaoll UM (1/1) is a polycarbonate diol having a1, 4-CHD/1,6-HD 1/1 mole ratio relative to 1,4-CHD polycarbonate diol eteernaoll UC 100.

(example 8)

An aqueous polyurethane dispersion of example 8 was obtained in the same manner as in example 7. The water-based coating composition of example 8 was prepared in the same manner as in example 1 and with the formulation shown in table 4, using Carbodilite SW12G (carbodiimide, nonvolatile content 40%, carbodiimide equivalent 467) (manufactured by nippon chemical corporation) instead of Carbodilite V10.

(example 9)

An aqueous polyurethane dispersion of example 9 was obtained by using etenac ol UH100 (manufactured by yushu co., ltd.) in place of etenac ol UC100 as the component (a) and containing etenac ol UH100 in accordance with the compounding shown in table 5, and by the same procedure as in example 1. The aqueous coating composition of example 9 was prepared from the resulting aqueous polyurethane dispersion by using Carbodilite V10 in place of Carbodilite V02 in the same manner as in example 1 and with the compounding shown in table 5. Note that ETERNACOLL UH100 is a1, 6-HD polycarbonate diol.

(example 10)

An aqueous polyurethane dispersion of example 10 was obtained in the same manner as in example 9. The water-based coating compositions of example 10 were prepared in the same manner as in example 1 and with the formulation shown in table 5, using Carbodilite SW12G (carbodiimide, nonvolatile content 40%, carbodiimide equivalent 467) (manufactured by nippon chemical corporation) instead of Carbodilite V10.

(example 11)

An aqueous polyurethane dispersion of example 11 was obtained in the same manner as in example 9. The water-based coating compositions of example 11 were prepared in the same manner as in example 1, except that Carbodilite E05 (carbodiimide, nonvolatile content 40%, carbodiimide equivalent 304) (manufactured by Nisshinbo chemical Co., Ltd.) was used in place of Carbodilite V10, in accordance with the formulation shown in Table 5.

(example 12)

The aqueous polyurethane dispersion of example 12 was obtained by the same procedure as in example 1, except that the aqueous polyurethane dispersion of example 12 was prepared by using Polylite ODX-2155 (manufactured by Daiiol Co., Ltd.) in place of ETERNACOLL UC100 as component (A) and compounding Polylite ODX-2155 as shown in Table 6. In addition, the water-based coating composition of example 12 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 6 in the same manner as in example 1. It is noted that Polylite ODX-2155 is a diol of polycaprolactone.

(example 13)

An aqueous polyurethane dispersion of example 13 was obtained in the same manner as in example 12. The water-based coating compositions of example 13 were prepared in the same manner as in example 1 and with the formulation shown in table 6, using Carbodilite V10 (carbodiimide, nonvolatile content 40%, carbodiimide equivalent 410) (manufactured by nippon chemical) instead of Carbodilite V02.

(example 14)

The aqueous polyurethane dispersion of example 14 was obtained by reducing the amount of etaernaoll UC100 as component (a) relative to example 1, adding the components in the blend amounts shown in table 7, and performing the same steps as in example 1. In addition, the water-based coating composition of example 14 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 7 in the same manner as in example 1.

(example 15)

The aqueous polyurethane dispersion of example 15 was obtained by adding ETERNACOLL UC100 as component (A) to example 2, adding the components in the amounts shown in Table 7, and carrying out the same procedure as in example 1. In addition, the water-based coating composition of example 15 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 7 in the same manner as in example 1.

(example 16)

The aqueous polyurethane dispersion of example 16 was obtained by the same procedure as in example 2 except that the amount of etaernaoll UC100 as component (a) was made larger than that in example 15 and the components were contained in the amounts shown in table 8. In addition, the water-based coating composition of example 16 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 8 in the same manner as in example 1.

(example 17)

The aqueous polyurethane dispersion of example 17 was obtained by the same procedure as in example 2, except that the amount of ETERNACOLL UC100 as component (A) was made larger than that in example 16, and the components were contained in the amounts shown in Table 8. In addition, the water-based coating composition of example 17 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 8 in the same manner as in example 1.

(example 18)

Aqueous polyurethane dispersions of example 18 were obtained by the same procedure as in example 1, containing the components in the proportions shown in Table 9. In addition, the water-based coating composition of example 18 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 9 in the same manner as in example 1.

(example 19)

Aqueous polyurethane dispersions of example 19 were obtained by the same procedure as in example 1, containing the components in the proportions shown in Table 9. In addition, the water-based coating composition of example 19 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 9 in the same manner as in example 1.

(example 20)

Aqueous polyurethane dispersions of example 20 were obtained by the same procedure as in example 1, containing the components in the proportions shown in Table 9. In addition, the water-based coating composition of example 20 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 9 in the same manner as in example 1.

Comparative example 4

The same procedure as in example 1 was carried out with the components contained in the blend shown in Table 10, but gelation was observed in the polyurethane synthesis step (1). Therefore, an aqueous coating composition cannot be prepared.

(example 21)

The content of TMP as component (C) was reduced compared to example 1, and the aqueous polyurethane dispersions of example 21 were obtained by the same procedure as in example 1, except that the components were contained in the blend shown in table 10. In addition, the water-based coating composition of example 21 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 10 in the same manner as in example 1.

Comparative example 5

In comparison with example 14, TMP as component (C) was added to example 21 in an amount larger than that of example 14, and the same procedure as in example 1 was carried out by containing each component in the blend shown in table 10. However, gelation was observed in the polyurethane synthesis step (1). Therefore, an aqueous polyurethane dispersion cannot be prepared.

(example 22)

The amount of DMPA as component (D) was reduced compared to that of example 1, and each component was contained in the blend shown in Table 11 in comparison with example 1, to obtain an aqueous polyurethane dispersion of example 22 by the same procedure as in example 1. In addition, the water-based coating composition of example 22 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 11 in the same manner as in example 1.

Example 23 (corresponding to example 20)

The aqueous polyurethane dispersions of example 23 were obtained by the same procedure as in example 1 except that the amount of DMPA as component (D) in example 1 was changed to larger than that in example 1 and the components were contained in the amounts shown in Table 11. In addition, the water-based coating composition of example 23 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 11 in the same manner as in example 1.

(example 24)

The amount of DMPA as component (D) was increased from that of example 1 to that of example 23, and the components were contained in the blend shown in Table 11, to obtain an aqueous polyurethane dispersion of example 24 by the same procedure as in example 1. In addition, the water-based coating composition of example 24 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 11 in the same manner as in example 1.

(example 25)

Aqueous polyurethane dispersions of example 25 were obtained by the same procedure as in example 1, except that TEA (triethylamine) (manufactured by Mitsubishi gas chemical Co., Ltd.) was contained in place of DMEA as a neutralizer, and the components were contained in the proportions shown in Table 12. In addition, the water-based coating composition of example 25 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 12 in the same manner as in example 1.

(example 26)

In contrast to example 1, aqueous polyurethane dispersions of example 26 were obtained by the same procedure as in example 1, except that DMBA (dimethylolbutanoic acid) (manufactured by western sky blue industries, ltd.) was contained in place of DMPA as the component (D) and the components were contained in the formulation shown in table 12. In addition, the water-based coating composition of example 26 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 12 in the same manner as in example 1.

(example 27)

In contrast to example 2, 1,6-HD (1, 6-hexanediol) (manufactured by Udo Kyoho Co., Ltd.) was used in place of 1,4-CHD as the component (B), and 1,6-HD was contained in the formulation shown in Table 13, and the aqueous polyurethane dispersion of example 27 was obtained by the same procedure as in example 1. In addition, the water-based coating composition of example 27 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 13 in the same manner as in example 1.

(example 28)

In example 2, 1,6-HD was used in addition to 1,4-CHD as the component (B), and 1,4-CHD and 1,6-HD were contained in the formulation shown in Table 14, and the aqueous polyurethane dispersion of example 28 was obtained by the same procedure as in example 1. In addition, the water-based coating composition of example 28 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 14 in the same manner as in example 1.

(example 29)

In example 1,4-BG (1, 4-butanediol) (manufactured by mitsubishi chemical corporation) was used in addition to 1,4-CHD as the component (B), 1,4-CHD and 1,4-BG were contained in the formulation shown in table 14, and the aqueous polyurethane dispersion of example 29 was obtained through the same steps as in example 1. In addition, the water-based coating composition of example 29 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 14 in the same manner as in example 1.

(example 30)

In example 1,6-HD was used in addition to 1,4-CHD as the component (B), and 1,4-CHD and 1,6-HD were contained in the formulation shown in Table 14, and the aqueous polyurethane dispersion of example 30 was obtained by the same procedure as in example 1. In addition, the water-based coating composition of example 30 was prepared from the obtained polyurethane aqueous dispersion according to the formulation shown in table 14 in the same manner as in example 1.

(example 31)

The same formulation as in example 30 was repeated to obtain an aqueous polyurethane dispersion of example 31. An aqueous coating composition of example 31 was prepared in the same manner as in example 1 using Carbodilite V10 instead of Carbodilite V02, with the formulation shown in table 14.

[ investigation on crosslinking Agents in Water-based coating compositions (comparative examples 6 and 7 and examples 32 to 40) ]

Next, using the aqueous polyurethane dispersion of example 29, a crosslinking agent in an aqueous coating composition was examined as shown in comparative examples 6 and 7 and examples 32 to 40 below. The results are shown in tables 15 and 16.

Comparative example 6

As shown in table 15, the aqueous coating composition of comparative example 6 was prepared by adding TEGO FOAMEX 8000.1 parts as an antifoaming agent and BYK-34550.15 parts as a leveling agent to 100 parts of the aqueous polyurethane dispersion having a nonvolatile content of 30% using the aqueous polyurethane dispersion of example 29, thickening the mixture to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 parts as a thickening agent, and defoaming the mixture. In comparative example 6, no crosslinking agent was added.

Comparative example 7

As shown in table 15, the aqueous polyurethane dispersion of example 29 was used, and to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V026.80 parts as a crosslinking agent were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener, and defoamed to prepare an aqueous coating composition of comparative example 7.

(example 32)

As shown in table 15, the aqueous polyurethane dispersion of example 29 was used, and to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V0213.54 parts as a crosslinking agent were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener, and defoamed to prepare an aqueous coating composition of example 32.

(example 33)

As shown in table 15, the aqueous polyurethane dispersion of example 29 was used, and to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V0220.30 parts as a crosslinking agent were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener, and defoamed to prepare an aqueous coating composition of example 33.

Example 34 (corresponding to example 29)

Example 34 corresponds to example 29, and the water-based coating composition of example 34 was prepared in the same manner as in example 29. As shown in Table 15, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V0225.72 parts as a crosslinking agent were added to 100 parts of the polyurethane aqueous dispersion having a nonvolatile content of 30% using the polyurethane aqueous dispersion of example 29.

(example 35)

As shown in table 15, the aqueous coating composition of example 35 was prepared by adding TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V0227.10 parts as a crosslinking agent to 100 parts of the aqueous polyurethane dispersion having a nonvolatile content of 30% using the aqueous polyurethane dispersion of example 29, thickening the mixture to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 parts as a thickening agent, and defoaming the mixture.

(example 36)

As shown in table 16, the aqueous polyurethane dispersion of example 29 was used, and to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Carbodilite V0232.49 parts as a crosslinking agent were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener, and defoamed to prepare an aqueous coating composition of example 36.

(example 37)

As shown in table 16, the aqueous polyurethane dispersion of example 29 was used, and to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, YK-34550.15 parts as a leveling agent, and Carbodilite V0240.60 parts as a crosslinking agent were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener, and defoamed to prepare an aqueous coating composition of example 37.

(example 38)

As shown in table 16, using the aqueous polyurethane dispersion of example 29, 4.04 parts of TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Aquanate210 (AQ210, HDI isocyanate, NCO% 16.5%) as a crosslinking agent (manufactured by tokyo co) were added to 100 parts of the aqueous polyurethane dispersion having a nonvolatile content of 30% (to 100 parts), and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener and defoamed to prepare an aqueous coating composition of example 38.

(example 39)

As shown in table 16, the aqueous coating composition of example 39 was prepared by adding TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, and Aquanate 2106.06 parts as a crosslinking agent to 100 parts of the aqueous polyurethane dispersion having a nonvolatile content of 30% using the aqueous polyurethane dispersion of example 29, thickening the mixture to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 parts as a thickening agent, and defoaming the mixture.

(example 40)

As shown in table 16, using the aqueous polyurethane dispersion of example 29, to 100 parts of an aqueous polyurethane dispersion having a nonvolatile content of 30%, TEGO FOAMEX 8000.1 parts as an antifoaming agent, BYK-34550.15 parts as a leveling agent, Carbodilite V0225.72 parts as a crosslinking agent, and Aquanate 2101.68 parts were added, and the mixture was thickened to a viscosity of about 1000(mPa · s/° c) with Adekanol UH450 as a thickener and defoamed to prepare a coating formulation of example 40.

[ preparation of coating film sample ]

Coating film samples were formed from each of the water-based coating compositions of the examples and comparative examples and evaluated. In order to prepare a coating film sample, a test substrate (2 mm. times.70 mm. times.150 mm) (manufactured by Taiyou products) made of ABS was prepared as a test substrate. Then, a test substrate was coated with a film having a thickness of 30 to 35 μm by a bar coater. Then, the resultant was cured for 30 minutes in a hot air dryer at 85 ℃ and then cured for 4 hours at 50 ℃ to prepare a coating sample.

[ evaluation of coating film sample

The coating film was evaluated as follows. First, as appearance evaluation, the appearance of the coating film was evaluated visually. The case of transparency was evaluated as "excellent", the case of substantial transparency was evaluated as "good", the case of turbidity but being usable was evaluated as "ok", and the case of turbidity, white turbidity and being unusable was evaluated as "not usable".

The pencil hardness test was carried out by a hand-scraping method in accordance with the pencil scratch test defined in the original JISK 5400. First, the tip of a pencil used for the test was placed against 400 grit sandpaper on a hard flat surface at a right angle, and the pencil was ground so that the tip was flat and the angle gradually became sharp. The ground lead was pressed against the test surface at 45 degrees, and the coated surface was pressed as hard as possible, but the lead was not broken, and the ground lead was pushed at a uniform speed by about 1cm in the direction of the test person to scrape the coated surface. The extrusion speed was about 1 cm/s. The tip of the lead of the pencil was ground every scraping, and the test was repeated 5 times using pencils with the same hardness marks. The hardness mark of the next pencil hardness at which the coating film was cracked or scratched was recorded 2 or more times in 5 tests. As evaluation criteria, evaluation was made in the order of-2H, F, HB, B, 2B, 3B, 4B, 5B to soft.

A cross cut test was performed as a test for the adhesion of the coating film. The cross cut test was carried out in accordance with the cross cut adhesion test specified in the original JISK 5400. Using a cutter, 11 scratches reaching the base were made on the test surface at 1mm intervals to make 100 squares. Then, the transparent adhesive tape was firmly pressed to the portions of the squares, and peeled off from the end of the tape at once at an angle of 45 °, and the states of the squares were compared and evaluated as a standard chart. The case of "100/100" was evaluated as "excellent", the case of "90/100" or more was evaluated as "good", the case of "70/100" or more was evaluated as "ok", and the case of "69/100" or less was evaluated as "not ok".

The self-repair test was performed as follows. The film is vertically abutted by a brass wire brush, and the surface of the film is rubbed about 5 to 10 times to form about 40 scratches on the surface of the film. The number of scratches was recorded, and the test piece was left at 20 ℃ and counted by visual observation for 24 hours while counting time. As an evaluation criterion, the self-repair ratio (number of steel wire trace remaining tracks/initial track) × 100 was evaluated in percentage. The case where the self-repair rate was 100% within 24 hours was evaluated as "excellent", the case where the self-repair rate was 70% or more was evaluated as "good", the case where the self-repair rate was 10% or more was evaluated as "ok", and the case where the self-repair rate was less than 10% was evaluated as "not ok". Note that when the self-repair rate is 100% within 24 hours, the self-repair time is also described.

The UV absorber resistance test was carried out as follows. Coating the coating film with 40g/m²Commercially available Lodeqing (R)100+ (manufactured by Neutrogena, USA under the formal name Ultra sheet (R) Dry-Touch Sunscreen Broad Spectrum SPF 100+) and left at 50 ℃ for 4 hours. Returning to normal temperature, cleaning with cleaning agent to obtain distillate (R)100+, washing, and wiping water. Next, the pencil hardness test was performed in the same manner as described above, and the state of deterioration was evaluated. The case where no change in hardness was observed was evaluated as "excellent", the case where the hardness was reduced only by 1 rank was evaluated as "good", and the case where the hardness was reduced by 2 ranks or more or damage was caused on the coating film was evaluated as "impossible".

In the above evaluation, the "good" evaluation and the "good" evaluation are considered to have full utility, and the "ok" evaluation is considered to have utility as needed. However, the evaluation of "impossible" is not practical. The evaluation results are shown in tables 1 to 16 below. In tables 1 to 16, example 1 and the like are repeated from the viewpoint of easy understanding. In addition, in the table, "f₁₀₀₀"represents" the average value of the molecular weight of the OH group-containing polyurethane per 1000, which is the total number of OH groups contained in all the polyols constituting the structural unit (A1), the structural unit (B1), the structural unit (C1) and the structural unit (D1), i.e., the f value ". In the table, "EM resin" represents each of the aqueous polyurethane dispersions.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

[ Table 6]

[ Table 7]

[ Table 8]

[ Table 9]

[ Table 10]

[ Table 11]

[ Table 12]

[ Table 13]

[ Table 14]

[ Table 15]

[ Table 16]

First, referring to tables 1 and 2 in which polyisocyanate components were compared, example 2 containing xylylene diisocyanate as a component (Ea) was excellent in appearance evaluation and ultraviolet absorber resistance, and was found to have practical levels of adhesion and self-repairability. Example 1 containing xylylene diisocyanate as the component (Ea) and HDI as the component (Eb) was excellent in the appearance evaluation, the adhesion, the self-repairing property and the ultraviolet absorber resistance. Example 3, which contains xylylene diisocyanate as component (Ea) and Lupranate MI as component (Eb), is excellent in appearance evaluation and ultraviolet absorber resistance, and has practical levels of adhesion and self-repairing properties. Further, example 4 containing xylylene diisocyanate as the component (Ea) and Desmodur I as the component (Eb) was excellent in the appearance evaluation, the adhesion property and the self-healing property, and the ultraviolet absorber resistance was good.

On the other hand, comparative examples 1 and 2, which contained poly (di) isocyanate as the (Eb) component but did not contain xylylene diisocyanate as the (Ea) component, had poor self-repairability and poor ultraviolet absorber resistance, although they were excellent in appearance evaluation. In comparative example 3, which contained poly (di) isocyanate as the (Eb) component but did not contain xylylene diisocyanate as the (Ea) component, NCO did not disappear and evaluation could not be made.

Next, referring to tables 3 to 6 for comparing the component (a), in example 5 using polycarbonate diol eternaoll UM (3/1) in a1, 4-CHD/1,6-HD 3/1mol ratio in place of polycarbonate diol eternaoll UC100 as the component (a), the appearance evaluation, the adhesion, the self-healing property, and the ultraviolet absorber resistance of example 5 were all excellent, similarly to example 1. In addition, example 6, in which Carbodilite V10 was used instead of Carbodilite V02 in example 5, was excellent in appearance evaluation, adhesion, and ultraviolet absorber resistance, and was good in self-repairing property.

In example 7 in which polycarbonate diol ETERNACOLLUM (1/1) having a1, 4-CHD/1,6-HD of 1/1mol ratio was used as the component (A) in place of 1,4-CHD polycarbonate diol ETERNACOLL UC100, the appearance evaluation, the adhesion, the self-healing property and the ultraviolet absorber resistance of example 7 were also excellent, similarly to example 1. In addition, in example 8 in which Carbodilite SW12G was used instead of Carbodilite V10 in example 7, the appearance evaluation, the adhesion and the ultraviolet absorber resistance were excellent, and the self-repairing property was good.

In example 9 in which 1,6-HD polycarbonate diol ETERNACOLL UH100 was used instead of 1,4-CHD polycarbonate diol ETERNACOLL UC100 as component (A), the appearance evaluation, the adhesion, the self-healing property and the ultraviolet absorber resistance of example 9 were also excellent in the same manner as in example 1. Also, in example 10 in which Carbodilite SW12G was used instead of Carbodilite V10 in example 9, the appearance evaluation, the adhesion, the self-healing property and the ultraviolet absorber resistance of example 10 were all excellent, similarly to example 9. In addition, in example 11 in which Carbodilite E05 was used instead of Carbodilite V10 in example 9, the appearance evaluation, the adhesion and the ultraviolet absorber resistance were excellent, and the self-repairing property was good.

Example 12, in which 1,4-CHD was replaced with 1,4-CHD polycarbonate diol ETERNACOLL UC100, which was prepared using polycaprolactone diol Polylite ODX-2155 as component (A), was excellent in appearance evaluation, adhesion, self-repairability, and ultraviolet absorber resistance. In addition, in example 13 in which Carbodilite V10 was used instead of Carbodilite V02 in example 12, the appearance evaluation, the adhesion and the ultraviolet absorber resistance were excellent, and the self-repairing property was good.

Then, referring to tables 7 and 8 in which the contents of the component (A) were compared, the appearance evaluation, the self-repairability and the ultraviolet absorber resistance were excellent for example 14 containing 1,4-CHD polycarbonate diol ETERNACOLL UC 10016.54 mass% as the component (A). The clinging property reaches the practical level. It is to be noted that this content corresponds to 0.25 mol%. The polycarbonate diol ETERNACOLL UC10032.38 mass% containing 1,4-CHD as component (A) in example 15 was excellent in the appearance evaluation and the ultraviolet absorber resistance. The self-repairing property and the adhesion property were good levels, respectively. It is to be noted that this content corresponds to 0.6 mol%. Also in example 16 containing 1,4-CHD polycarbonate diol ETERNACOLL UC10044.11 mass% as component (A), the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of example 16 were excellent in the same manner as in example 1. It is to be noted that this content corresponds to 0.95 mol%. Also in example 17 containing 1,4-CHD polycarbonate diol ETERNACOLL UC 10046.83 mass% as component (A), the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of example 17 were excellent in the same manner as in example 1. It is to be noted that this content corresponds to 1.05 mol%.

Referring to tables 9 and 10 in which the weight average molecular weights were compared, example 18, which was a blend ratio shown in table 9 and in which the OH group-containing polyurethane had a weight average molecular weight of 26658, was excellent in self-repairability and ultraviolet absorber resistance. In addition, the appearance evaluation and the adhesion were also good. Also in example 19, which was a blend ratio shown in Table 9 and in which the weight average molecular weight of the OH group-containing polyurethane was 87980, the appearance evaluation, self-repairability, adhesion, and ultraviolet absorber resistance of example 19 were excellent in the same manner as in example 1. Also in example 20 in which the compounding ratio shown in Table 9 and the weight average molecular weight of the OH group-containing polyurethane was 111072, the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of example 20 were excellent in the same manner as in example 1.

Referring to table 10 in which the contents of component (C) were compared, comparative example 4, which was a compounding ratio shown in table 10 and had an OH group-containing polyurethane with a weight average molecular weight of 145116, was not evaluated because gelation occurred during synthesis. Also in example 21 containing 1.99 mass% of TMP as the component (C), the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of example 21 were excellent in the same manner as in example 1. Comparative example 5, which contained 10.35 mass% of TMP as component (C) at the compounding ratio shown in table 10, was not evaluated because gelation occurred during synthesis.

Next, referring to table 11 in which the contents of the component (D) were compared, example 22 containing 5.54 mass% of DMPA as the component (D) at the blending ratio shown in table 11 was evaluated to have a good appearance, but was excellent in self-repairability, adhesion, and ultraviolet absorber resistance. Example 23, which contained 9.55 mass% of DMPA as component (D), was excellent in all of appearance evaluation, self-repairability, adhesion, and ultraviolet absorber resistance. It is to be noted that this content corresponds to 1.2 mol%. Example 24 containing 11.12 mass% of DMPA as component (D) was excellent in the appearance evaluation and self-repairing property, and was excellent in the adhesion and ultraviolet absorber resistance. It is to be noted that this content corresponds to 1.4 mol%.

Next, referring to table 12 in which the neutralizing agent and the component (D) were compared, example 25 in which TEA (triethylamine) was used instead of DMEA as the neutralizing agent was excellent in self-repairability and ultraviolet absorber resistance, and good in appearance evaluation and adhesion. In example 26 in which DMBA (dimethylolbutanoic acid) was used instead of DMPA as the component (D), the evaluation of the appearance, the adhesion and the self-repairing property were excellent, and the ultraviolet absorber resistance was good.

Next, referring to tables 13 and 14 in which the component (B) was compared, the appearance evaluation and the adhesion were at practical levels for example 27 in which 1,6-HD was used instead of 1,4-CHD as the component (B). In addition, the self-repairability is excellent, and the ultraviolet absorber resistance is good. In example 28 containing 1,6-HD as component (B) in addition to 1,4-CHD, the appearance evaluation, self-repairability and ultraviolet absorber resistance are excellent, and the adhesion is good level. In example 29 in which 1,4-BG was used as the component (B) in addition to 1,4-CHD, the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of example 29 were all excellent, similarly to example 1. In examples 30 and 31, which contained 1,6-HD as the component (B) in addition to 1,4-CHD as in example 28 but contained 1,4-CHD at a higher content than in example 28, the appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance of examples 30 and 31 were all excellent as in example 1.

[ results of investigation on crosslinking agent in Water-based coating composition ]

Referring to tables 15 and 16 in which the crosslinking agents were compared, in comparative example 6 in which no crosslinking agent was added and comparative example 7 in which Carbodilite V026.80 parts was added as a crosslinking agent, the coatings of comparative example 6 and comparative example 7 were damaged in the evaluation of the ultraviolet absorber resistance.

On the other hand, in example 32 in which 0213.54 parts of Carbodilite V was added as a crosslinking agent, the coating composition was excellent in appearance evaluation, adhesion and self-healing properties, and also excellent in UV absorber resistance. Examples 33, 34 and 35, in which Carbodilite V0220.30 parts was added as a crosslinking agent, 25.72 parts were added, and 27.10 parts were added, all of which were excellent in appearance evaluation, self-repairability, adhesion and ultraviolet absorber resistance. In example 36 in which 0232.49 parts of Carbodilite V was added as a crosslinking agent, the coating composition was excellent in appearance evaluation, self-repairability and ultraviolet absorber resistance, and also good in adhesion. Example 37, in which Carbodilite V0240.60 parts was added as a crosslinking agent, was excellent in appearance evaluation, self-repairability and ultraviolet absorber resistance, and was found to have practical adhesion

Referring to Table 16, in example 38 in which 4.04 parts of Aquanate210 (AQ 210: isocyanate crosslinking agent) was used instead of 02 parts of Carbodilite V as a crosslinking agent, the appearance evaluation, self-repairability and ultraviolet absorber resistance were good, and the adhesion was excellent. In example 39 using 2106.06 parts of Aquanate as a crosslinking agent, the appearance evaluation and self-repairability were at practical levels, and the adhesion and ultraviolet absorber resistance were excellent. In example 40 in which Carbodilite V02 and Aquanate210 were used in combination as a crosslinking agent, the composition was excellent in all of appearance evaluation, self-healing properties, adhesion properties and ultraviolet absorber resistance.

As described above, the aqueous polyurethane dispersion according to the present invention can provide an aqueous polyurethane dispersion that can form a coating film having self-repairability and ultraviolet absorber resistance.

All aspects of the embodiments and examples disclosed herein are examples, and it should be understood that the present disclosure is not limited thereto in any way. The scope of the present invention is defined not by the above description but by the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

Industrial applicability

The aqueous polyurethane dispersion, the method for producing the aqueous polyurethane dispersion, the aqueous coating composition, and the coating film according to the present invention can reduce environmental load, and can be used particularly effectively when an aqueous polyurethane dispersion and a coating film capable of forming a coating film excellent in self-repairability and ultraviolet absorber resistance are required.

Claims (16)

1. An aqueous polyurethane dispersion comprising:

water; and

a neutralized product of an OH group-containing polyurethane having an OH group at a molecular chain terminal and a tertiary amine dispersed in the water;

the OH group-containing polyurethane contains in the molecular chain:

a structural unit (a1) derived from a polyol (a) which is at least one of a polycarbonate polyol and a polyester polyol and has a number average molecular weight of more than 500 and not more than 5000;

a structural unit (B1) derived from a first diol (B) having a number average molecular weight of 500 or less and having no carboxyl group;

a structural unit (C1) derived from a polyvalent alcohol (C) having a number-average molecular weight of 500 or less and a number of functional groups per molecule of more than 2 and 4 or less;

a structural unit (D1) from a second diol (D) having a carboxyl group; and

a structural unit (E1) derived from a diisocyanate component (E) comprising xylylene diisocyanate (Ea), and a structural unit (E1) comprising a structural unit (E1a) derived from xylylene diisocyanate (Ea),

the weight average molecular weight of the OH group-containing polyurethane is 16000 or more and 140000 or less.

2. The aqueous polyurethane dispersion according to claim 1,

the proportion of the structural unit (A1) derived from the polyol (A) in the molecular chain of the OH group-containing polyurethane is 10 to 60 mass% in terms of mass.

3. The aqueous polyurethane dispersion according to claim 1 or claim 2,

when all OH groups contained in all polyols that are sources of the structural unit (A1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) are reacted with all NCO groups contained in diisocyanate that is a source of the structural unit (E1), and the total number of OH groups contained in OH-group-containing polyurethane formed by the reaction is defined as f, the average value of the f-number per 1000 calculated molecular weight of the OH-group-containing polyurethane, that is, f₁₀₀₀The value is 2.1 or more and 2.And 9 or less.

4. The aqueous polyurethane dispersion according to claim 1 or claim 2,

the OH group-containing polyurethane has an acid value of 14 to 55 inclusive.

5. The aqueous polyurethane dispersion according to claim 1 or claim 2,

the structural unit (E1) further includes a structural unit (E1b), and the structural unit (E1b) is derived from at least one diisocyanate selected from the group consisting of an aromatic diisocyanate compound other than xylylene diisocyanate (Ea), an alicyclic diisocyanate compound, and an aliphatic diisocyanate compound.

6. The aqueous polyurethane dispersion according to claim 1 or claim 2,

the polyol compound which can be used for the synthesis of the polycarbonate polyol is mainly composed of at least one of 1, 6-hexanediol and 1, 4-cyclohexanedimethanol,

the polyester polyol is mainly composed of lactone.

7. The aqueous polyurethane dispersion according to claim 1 or claim 2,

the structural unit (C1) derived from a polyvalent alcohol is mainly composed of a structural unit composed of trimethylolpropane.

8. The aqueous polyurethane dispersion according to claim 1 or claim 2,

the structural unit (B1) derived from the first diol is mainly composed of a structural unit composed of 1, 4-cyclohexanedimethanol.

9. A method for producing the aqueous polyurethane dispersion according to claim 1, comprising:

a polyurethane synthesis step (1) of reacting the polyol (a), the first diol (B), the polyvalent alcohol (C), the second diol (D), and the diisocyanate component (E) to synthesize the OH group-containing polyurethane having a weight average molecular weight of 16000 or more and 140000 or less;

a neutralization step (2) for neutralizing the OH group-containing polyurethane synthesized by the neutralization step with a neutralizing agent comprising the tertiary amine; and

and a production step (3) of dispersing the neutralized product formed in the neutralization step in water to produce an aqueous polyurethane dispersion in which the neutralized product is dispersed in water.

10. The method for producing an aqueous polyurethane dispersion according to claim 9,

the proportion of the structural unit (a1) derived from the polyol (a) in the entire OH group-containing polyurethane synthesized in the polyurethane synthesis step (1) is 10 mass% or more and 60 mass% or less in terms of mass ratio.

11. The method for producing an aqueous polyurethane dispersion according to claim 9 or claim 10,

when all OH groups contained in all polyols from which the structural unit (a1), the structural unit (B1), the structural unit (C1) and the structural unit (D1) are derived in the OH group-containing polyurethane synthesized in the polyurethane synthesis step (1) are reacted with all NCO groups contained in diisocyanate from which the structural unit (E1) is derived, and the total number of OH groups contained in the OH group-containing polyurethane formed by the reaction is defined as a value f, the OH group-containing polyurethane having an average value of the value f, that is, the value f, per 1000 calculated molecular weight of the OH group-containing polyurethane is synthesized₁₀₀₀The value is 2.1 or more and 2.9 or less.

12. The method for producing an aqueous polyurethane dispersion according to claim 9 or claim 10,

in the polyurethane synthesis step (1), the reaction is carried out so that the OH group-containing polyurethane has an acid value of 14 to 55 inclusive.

13. The method for producing an aqueous polyurethane dispersion according to claim 9 or claim 10,

the diisocyanate component (E) contains xylylene diisocyanate (Ea) and at least one diisocyanate (Eb) selected from the group consisting of aromatic diisocyanate compounds other than xylylene diisocyanate (Ea), alicyclic diisocyanate compounds and aliphatic diisocyanate compounds.

14. A water-based coating composition comprising:

an aqueous polyurethane dispersion according to claim 1 as a first dispersion;

at least one dispersion of a carbodiimide crosslinking agent aqueous dispersion and a dispersion of a polyisocyanate crosslinking agent as a second dispersion, the dispersion of the carbodiimide crosslinking agent aqueous dispersion containing carbodiimide groups of 150 molar equivalents or more and 600 molar equivalents or less as nonvolatile components; the polyisocyanate crosslinking agent dispersion contains 5 to 25 mass% of isocyanate groups as nonvolatile components in terms of mass,

a molar equivalent ratio N (C) N/COOH of a carbodiimide group in the carbodiimide crosslinking agent contained in the aqueous dispersion of the carbodiimide crosslinking agent to a carboxyl group in the OH group-containing polyurethane contained in the aqueous dispersion of the polyurethane is 0.30 or more and 1.7 or less,

the molar equivalent ratio NCO/OH of the isocyanate groups in the polyisocyanate crosslinking agent contained in the polyisocyanate crosslinking agent dispersion and the OH groups in the OH group-containing polyurethane contained in the polyurethane aqueous dispersion is 0.30 or more and 2.5 or less.

15. The water-based coating composition according to claim 14, comprising:

a first liquid containing said aqueous polyurethane dispersion,

a second liquid comprising at least one dispersion of the aqueous dispersion of carbodiimide crosslinker and the dispersion of polyisocyanate crosslinker.

16. A coating film formed by applying the water-based coating composition according to claim 14 or claim 15 to a substrate.

Images