JPWO2015033939A1 - Aqueous polyurethane resin dispersion and use thereof - Google Patents

Abstract

The aqueous polyurethane resin dispersion of the present invention comprises (a) a polyisocyanate compound (b) a polyester polycarbonate polyol [PEsC], a mixture of a polyester polyol [PEs] and a polycarbonate polyol [PC], or the same [PEsC]. PEs] and / or a mixture thereof with [PC] (c) Acid group-containing polyol compound (d) (A) polyurethane prepolymer which is a reaction product of an NCO group blocking agent that dissociates at 80 to 180 ° C .; B) The polyurethane resin obtained from the chain extender is dispersed in an aqueous medium, and the resin has Mw = 20,000 to 100,000 and the following content ratio (solid content basis). Total of urethane bond + urea bond; 8 to 15% by weight carbonate bond; 4 to 23% by weight ester bond; 2 to 16% by weight alicyclic structure; 7 to 30% by weight NCO group (NCO group to which the blocking agent is bound) Conversion); 0.2-2.0 wt%

Description

  The present invention relates to an aqueous polyurethane resin dispersion in which a polyurethane resin is dispersed in an aqueous medium. The present invention also relates to a coating composition containing the aqueous polyurethane resin dispersion and a polyurethane resin film obtained by heating and drying the composition containing the polyurethane resin dispersion.

The water-based polyurethane resin dispersion is an environmentally friendly material that can provide a coating film having adhesiveness, abrasion resistance, rubber-like properties, etc., and can reduce volatile organic substances compared to conventional solvent-based polyurethane. It is a material that is being replaced by solvent-based polyurethane.
Polycarbonate polyol is a useful compound that can be used as a raw material for polyurethane resins. By reacting with isocyanate compounds, it produces durable polyurethane resins used for rigid foams, flexible foams, paints, adhesives, synthetic leather, ink binders, etc. can do. The characteristics of the polyurethane resin using polycarbonate polyol are expressed by the high cohesive strength of the carbonate group, and are described as being excellent in water resistance, heat resistance, oil resistance, elastic recovery, wear resistance, weather resistance, and the like ( For example, refer nonpatent literature 1). In addition, coating films obtained by applying an aqueous urethane resin dispersion using polycarbonate polyol as a raw material are also known to be excellent in light resistance, heat resistance, hydrolysis resistance, oil resistance, etc. (for example, patents) Reference 1).

  As described above, an aqueous polyurethane resin dispersion using a polycarbonate polyol exhibits good characteristics, but is not sufficient as compared with a solvent-based polyurethane. In particular, the solvent resistance and water resistance of the coating film are insufficient. In order to improve such characteristics, a crosslinked structure is introduced into a polyurethane resin, or a composition in which a crosslinking material such as an epoxy resin or a polyfunctional isocyanate is introduced is crosslinked at the time of curing. Among them, the aqueous polyurethane resin dispersion having a blocked isocyanato group is stable at room temperature, and thus has a high utility value as a one-part crosslinking reactive dispersion having high storage stability (for example, Patent Document 2 and Patent Reference 3). It is also known that an aqueous polyurethane resin dispersion using polycarbonate polyol as a raw material has a feature of high adhesion to an electrodeposited substrate (see, for example, Patent Document 4).

  Furthermore, the present inventors have controlled the film-forming speed after coating by an aqueous polyurethane resin dispersion having a specific amount of a blocked isocyanate group having a urethane bond, a urea bond, and a carbonate bond. The film can be redispersed in water, and the coating film obtained by applying and heat-treating it has excellent water resistance and solvent resistance, and adhesion to the electrodeposited substrate. In addition, it has been found that since the breaking energy in tension is high, the impact resistance is also excellent (see, for example, Patent Document 5).

  On the other hand, additives such as various pigments may be added to the aqueous polyurethane resin dispersion. When adding a pigment that is difficult to disperse in an aqueous medium, a water-insoluble organic solvent as a dispersant is added to the aqueous resin dispersion together with the pigment (see Patent Document 6).

  The present inventors added a water-insoluble organic solvent to the aqueous polyurethane resin dispersion by creating a crosslinked structure using a polyamine compound having a total of 3 or more amino groups and / or imino groups in one molecule. However, it has been found that the viscosity hardly increases (see Patent Document 7).

JP-A-10-120757 Japanese Patent Laid-Open No. 2002-128551 JP 2000-104015 A JP 2005-220255 A International Publication No. 2010/098316 JP 2003-327895 A International Publication No. 2012/1665569

“Latest Polyurethane Materials and Applied Technologies”, CMC Publishing Co., Ltd. Chapter 2 Page 43

When the aqueous polyurethane resin dispersion is used as a film, paint, or coating material, it is applied to a substrate or the like using an application device such as a bar coater, roll coater, or air spray. A coating film is formed on the substrate by heating and drying the applied aqueous polyurethane resin dispersion. However, in the conventional aqueous polyurethane resin dispersion, a coating film having excellent adhesion to the electrodeposited substrate and high breaking energy in tension could not be obtained. Furthermore, in the method of adding a water-insoluble organic solvent to the aqueous polyurethane resin dispersion as described in Patent Document 6, since the viscosity is remarkably increased, the handling property is poor, and the discharge when spraying is performed. There was a problem that the storage stability as a paint or a coating material composition was poor. Further, it has been found that there is room for improvement with respect to the breaking energy of the obtained coating film, compared to the method of introducing a crosslinked structure using a polyamine compound as described in Patent Document 7.
An object of the present invention is to provide a water-based polyurethane having a small increase in viscosity when added with a water-insoluble organic solvent, excellent adhesion to an electrodeposited substrate, and providing a coating film with high breaking energy in tension. It is to provide a resin dispersion.

The present invention has been made to solve the above problems, and specifically has the following configuration.
[1] At least (a) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500 and a number average molecular weight of 800 to A mixture with a polycarbonate polyol of 3,500, a polyester polycarbonate polyol with a number average molecular weight of 800 to 3,500, a polyester polyol with a number average molecular weight of 800 to 3,500 and / or a number average molecular weight of 800 (A) polyurethane prepolymer obtained by reacting a mixture with a polycarbonate polyol of ~ 3,500, (c) an acidic group-containing polyol compound, and (d) a blocking agent for an isocyanato group dissociating at 80 to 180 ° C And the poly The polyurethane resin obtained by reacting the chain extender (B) having reactivity with the isocyanate prepolymer of the retan prepolymer is dispersed in an aqueous medium, and the urethane bond content ratio and the urea bond content ratio are The total is 8 to 15% by weight based on solid content, the content of carbonate bonds is 4 to 23% by weight based on solids, and the content of ester bonds is 2 to 16% by weight based on solids, The content of the alicyclic structure is 7 to 30% by weight based on the solid content, and the content of the isocyanate group to which the blocking agent is bound is 0.2 to 2.0% by weight based on the solid content and in terms of the isocyanate group. An aqueous polyurethane resin dispersion having a weight average molecular weight of 20,000 to 100,000.
[2] The aqueous polyurethane resin dispersion according to [1], wherein the acid value is 10 to 32 mg KOH / g. [3] The aqueous polyurethane resin dispersion according to [1] or [2], wherein (a) the polyisocyanate compound is an alicyclic diisocyanate.
[4] (d) The aqueous polyurethane resin dispersion according to any one of [1] to [3], wherein the blocking agent is at least one selected from oxime compounds, pyrazole compounds and malonic ester compounds body.
[5] A coating material composition comprising the aqueous polyurethane resin dispersion according to any one of [1] to [4].
[6] A polyurethane resin film produced by heating and drying a composition containing the aqueous polyurethane resin dispersion according to any one of [1] to [4].

  According to the present invention, when adding a water-insoluble organic solvent, the increase in viscosity is small, the adhesiveness to the electrodeposited substrate is excellent, and a coating film with high breaking energy in tension is given. The body is provided.

  In this specification, the numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.

  The aqueous polyurethane resin dispersion of the present invention comprises at least (a) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, and a polyester polyol having a number average molecular weight of 800 to 3,500. And a polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500, and / Or obtained by reacting a mixture with a polycarbonate polyol having a number average molecular weight of 800 to 3,500, (c) an acidic group-containing polyol compound, and (d) a blocking agent for an isocyanato group dissociating at 80 to 180 ° C. (A) Poly A polyurethane resin obtained by reacting a retin prepolymer with a chain extender (B) having reactivity with the isocyanate group of the polyurethane prepolymer is dispersed in an aqueous medium, and the urethane bond content is The total content of urea bonds is 8 to 15% by weight on a solids basis, the content of carbonate bonds is 4 to 23% by weight on a solids basis, and the content of ester bonds is 2 to 2 on a solids basis. It is 16% by weight, the alicyclic structure content is 7 to 30% by weight on a solid basis, and the content of the isocyanate group to which the blocking agent is bound is 0.2 to 2 on a solid basis and in terms of isocyanato group. 0.0% by weight and a weight average molecular weight of 20,000 to 100,000.

Some conventional water-based polyurethane resin dispersions can be applied to a substrate, etc., and then the paint layer or paint film can be washed or removed to remove the paint layer or paint film and reapply. There is also a thing. However, there has been a problem that, along with facilitating recoating, the breaking energy in tension becomes low and the coating film is easily broken. Furthermore, when stored as a paint or a coating material composition, there is a problem that the viscosity is remarkably increased by mixing with a water-insoluble organic solvent.
According to the present invention, it is possible to give a coating film having a high breaking energy in tension, a high swelling ratio in an aqueous cleaning liquid (for example, an aqueous solution containing alcohol, amine, amino alcohol, cellosolve, etc.) and repainting. In addition, it is possible to obtain an aqueous polyurethane resin dispersion in which the viscosity does not increase remarkably by mixing with a water-insoluble organic solvent. Furthermore, when the polyester polycarbonate polyol is used as (b), high tensile strength and high breaking energy can be maintained even when the aqueous polyurethane resin dispersion is stored under basic conditions. The coating film formed from the aqueous polyurethane resin dispersion of the present invention is useful as a protective coating for an electrodeposition coating film on steel sheets for building materials, electrical equipment, vehicles, industrial equipment, office machines and the like.

Moreover, when obtaining the laminated coating film in which the coating film of multiple layers was provided, an aqueous coating material may be further apply | coated on the coating film of an aqueous polyurethane resin dispersion. When an aqueous coating material is applied on the coating film of the aqueous polyurethane resin dispersion, the surface smoothness of the laminated coating film may be lowered when the water resistance of the coating film is low.
According to the present invention, it is possible to obtain an aqueous polyurethane resin dispersion that has a high breaking energy in tension, a low swelling ratio in water, and a coating film having high water resistance. Moreover, since the coating film obtained using an aqueous polyurethane resin dispersion has high adhesiveness to an electrodeposition coating film, it can be utilized as a protective coating for steel sheets. Furthermore, the polyurethane resin film can be used as a decorative film.

[(A) polyisocyanate compound]
(A) The polyisocyanate compound (hereinafter also simply referred to as “(a)”) is not particularly limited as long as it is a compound having two or more isocyanate groups, and is an aromatic polyisocyanate compound, linear or branched. Any of an aliphatic polyisocyanate compound and an alicyclic polyisocyanate compound may be used. Specific examples of the polyisocyanate compound include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, and 4,4′-diphenylenemethane. Diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4 ′ -Aromatic polyisocyanate compounds such as diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate; ethylene diisocyanate, tetramethylene diisocyanate, Samethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis (2- Aliphatic polyisocyanate compounds such as isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate; isophorone diisocyanate (IPDI), 4,4 ′ -Dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis (2-isocyanatoethyl) -4-dichlorohexene 1,2-dicarboxylate, 2,5-norbornane diisocyanate, and alicyclic polyisocyanate compounds such as 2,6-norbornane diisocyanate Natick sulfonates and the like. These polyisocyanate compounds may be used individually by 1 type, and may use multiple types together.

  (A) Among the polyisocyanate compounds, alicyclic polyisocyanate compounds are preferable, and alicyclic diisocyanate compounds are more preferable. By using an alicyclic polyisocyanate compound, it is possible to obtain a coating film that is more difficult to yellow, and the hardness of the obtained coating film tends to be higher. Among the alicyclic polyisocyanate compounds, 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI) is particularly preferable from the viewpoints of controlling the reactivity and high elasticity of the resulting coating film and low water swelling ratio.

[(B) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a mixture of a polyester polyol having a number average molecular weight of 800 to 3,500 and a polycarbonate polyol having a number average molecular weight of 800 to 3,500, Or a mixture of a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and a polyester polyol having a number average molecular weight of 800 to 3,500 and / or a polycarbonate polyol having a number average molecular weight of 800 to 3,500]
(B) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 (hereinafter, also simply referred to as “polyester polycarbonate polyol”) and a polyester polyol having a number average molecular weight of 800 to 3,500 (hereinafter simply referred to as “polyester”). And a polycarbonate polyol having a number average molecular weight of 800 to 3,500 (hereinafter also simply referred to as “polycarbonate polyol”), or a polyester polycarbonate polyol and a polyester polyol and / or a polycarbonate polyol. The following (b1) to (b5) may be mentioned as a mixture of these (hereinafter, these are collectively referred to simply as “(b)”).
(B1) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500; (b2) a polyester polyol having a number average molecular weight of 800 to 3,500 and a polycarbonate polyol having a number average molecular weight of 800 to 3,500. (B3) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500, and a polycarbonate polyol having a number average molecular weight of 800 to 3,500 (B4) a mixture of a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and a polyester polyol having a number average molecular weight of 800 to 3,500; or (b5) a number average molecular weight of 800. ~ 3 A mixture of polycarbonate polyol 00 number average molecular weight and polyester polycarbonate polyol is is 800～3,500.

  As (b), when polyester polycarbonate polyol is used, when the aqueous polyurethane resin dispersion is stored under basic conditions, the resulting coating film has a small strength at tension and a small reduction rate in breaking energy at tension. Is preferable. Therefore, as (b), the above (b1), (b3), (b4) and (b5) are preferable, and (b1) is more preferable.

  When the number average molecular weight of (b) is less than 800, the breaking energy in tension of the obtained coating film is low. When the number average molecular weight of (b) exceeds 3,500, the film forming property of the resulting aqueous polyurethane resin dispersion is inferior. The number average molecular weight is more preferably 1,500 to 3,200, still more preferably 1,900 to 3,000, and 2,000 to 3,000, from the viewpoints of breaking energy and film-forming properties in coating tension. Is particularly preferred. When two or more kinds of polyester polycarbonate polyols having different molecular weights, polyester polyols and polycarbonate polyols are used in combination, the number average molecular weight when mixed is preferably within this range. When two or more kinds of polyurethane resin dispersions are used in combination, the number average molecular weight when all of the polyester polycarbonate polyol, polyester polyol and polycarbonate polyol used as raw materials are mixed is preferably within this range.

The number average molecular weight (Mn) of (b) is obtained from the hydroxyl value by the following formula.
Mn = (56100 × valence) / hydroxyl value In the above formula, the valence is the number of hydroxyl groups in one molecule, and the hydroxyl value is measured in accordance with B method of JIS K1557. For example, when (b) is polyester polycarbonate diol, a mixture of polyester diol and polycarbonate diol, or a mixture of polyester polycarbonate diol and polyester diol and / or polycarbonate diol, the valence is 2.

Examples of the polyester polycarbonate polyol include a polyester polycarbonate polyol composed of a carbonyl component, a polycarboxylic acid component and a polyol component, a polyester polycarbonate polyol composed of a carbonyl component, a hydroxycarboxylic acid component and a polyol component, and a carbonyl component and a polycarboxylic acid component. Examples thereof include polyester polycarbonate polyol composed of a hydroxycarboxylic acid component and a polyol component. These may be used individually by 1 type and may use multiple types together.
Examples of the polyester polyol include a polyester polyol composed of a polycarboxylic acid component and a polyol component, a polyester polyol composed of a hydroxycarboxylic acid component and a polyol component, and a polyester polyol composed of a polycarboxylic acid component, a hydroxycarboxylic acid component and a polyol component. Etc. These may be used individually by 1 type and may use multiple types together.
Examples of the polycarbonate polyol include a polycarbonate polyol composed of a carbonyl component and a polyol component. These may be used individually by 1 type and may use multiple types together.

  As a raw material which forms a carbonyl component, carbonate ester and phosgene are mentioned, for example. Carbonic acid ester is preferable as a raw material for forming the carbonyl component from the viewpoint that it does not contain chlorine atoms or chloride compounds and is difficult to be colored. Examples of carbonate esters include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; alkylene carbonates such as ethylene carbonate and propylene carbonate; diaryl carbonates such as diphenyl carbonate; alkyl aryl carbonates such as methyl phenyl carbonate and ethyl phenyl carbonate; Examples thereof include cyclic carbonates such as ethylene and propylene carbonate. These may be used individually by 1 type and may use multiple types together.

  As raw materials for forming the polycarboxylic acid component, oxalic acid, succinic acid, malonic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, saturated aliphatic polycarboxylic acid such as dodecanedicarboxylic acid; maleic acid, fumaric acid, Unsaturated aliphatic polycarboxylic acids such as itaconic acid; phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalene Aromatic polycarboxylic acids such as dicarboxylic acids, and acid anhydrides and acid halogenoids thereof may be mentioned. These may be used individually by 1 type and may use multiple types together.

  As raw materials for forming the hydroxycarboxylic acid component, glycolic acid, lactic acid, tartronic acid, glyceric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, malic acid, tartaric acid, 6-hydroxycaproic acid and other hydroxycarboxylic acids; α- Examples thereof include cyclic esters such as acetolactone, β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone. These may be used individually by 1 type and may use multiple types together. The raw material for forming the hydroxycarboxylic acid component is preferably an aliphatic lactone having 2 to 10 carbon atoms, more preferably an aliphatic lactone having 4 to 6 carbon atoms in terms of breaking energy, and more preferably ε-caprolactone.

As raw materials for forming the polyol component, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-pentanediol, 1,8 -Linear aliphatic diols such as octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,3-butanediol, 3-methylpentane-1,5- Branched aliphatic diols such as diol, 2-ethylhexane-1,6-diol, 2-methyl-1,3-pentanediol, neopentyl glycol, 2-methyl-1,8-octanediol; -Cyclohexanediol, 1,4-cyclohexanediol, 2,2'-bis (4-hydroxycyclohexyl) propane, 1,3 -Cycloaliphatic diols such as cyclohexanedimethanol and 1,4-cyclohexanedimethanol; aromatic diols such as 1,4-benzenedimethanol and bisphenol A; polyfunctional polyols such as trimethylolpropane and pentaerythritol Can do. Only one type of polyol can be used, or two or more types can be used in combination.
These polyols preferably have 2 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, and still more preferably 3 to 8 carbon atoms.

As the polyester polycarbonate polyol, polyester polyol and polycarbonate polyol in (b), the polyol component is composed of a linear aliphatic diol, a branched aliphatic diol, an alicyclic diol, an aromatic diol, and a polyfunctional polyol. Polyester polycarbonate polyols, polyester polyols, and polycarbonate polyols formed from one or more raw materials selected from the group consisting of these are preferable, and the polyol component is formed from a linear aliphatic diol and / or a branched aliphatic diol. Polyester polycarbonate polyols, polyester polyols, and polycarbonate polyols are more preferable, and polyester polycarbonate polyols in which the polyol component is formed from a linear aliphatic diol. Le, polyester polyol, even more preferably polycarbonate polyols.
The polycarbonate polyol is preferably a polycarbonate polyol containing an aliphatic diol or an alicyclic diol, more preferably a polycarbonate polyol containing an aliphatic diol, and particularly preferably a polycarbonate polyol containing 1,6-hexanediol.

Polyester polycarbonate polyol can be obtained by transesterifying one or more selected from the group consisting of polycarboxylic acid ester, hydroxycarboxylic acid ester, and cyclic ester with polycarbonate polyol, or by reacting each raw material. It can also be obtained by transesterifying a polyester polyol and a polycarbonate polyol. Here, examples of the ester of polycarboxylic acid include the ester of polycarboxylic acid. Moreover, as ester of hydroxycarboxylic acid, the ester of the said hydroxycarboxylic acid is mentioned.
Polyester polyol can be obtained by condensation polymerization of polycarboxylic acid and polyol, or can be obtained by transesterification of polycarboxylic acid ester and polyol, ring-opening polymerization of cyclic ester, hydroxy It can also be obtained by condensation polymerization of carboxylic acid or transesterification of hydroxycarboxylic acid ester.
The polycarbonate polyol can be obtained by a transesterification reaction between a polyol and a carbonate ester, or can be obtained by a method in which a polyol and phosgene are reacted.

[(C) Acid group-containing polyol compound]
(C) The acidic group-containing polyol compound (hereinafter also simply referred to as “(c)”) is not particularly limited as long as it is a compound having at least one acidic group and two or more hydroxy groups. Examples of the acidic group include a carboxy group and a sulfo group. The acidic group-containing polyol compound is preferably an acidic group-containing diol compound, and more preferably an acidic group-containing diol compound having 5 to 8 carbon atoms. Specific examples of the acidic group-containing polyol compound include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N, N-bishydroxyethylglycine, N, N-bishydroxyethylalanine, 3,4 -Dihydroxybutanesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid, etc. are mentioned. Although these can also use only 1 type, multiple types can also be used together. Among the acidic group-containing polyol compounds, 2,2-dimethylolpropionic acid is preferable from the viewpoint of availability.

[(D) Blocking agent]
(A) A part of the isocyanate group of the polyisocyanate compound is blocked by (d) a blocking agent for the isocyanate group dissociating at 80 to 180 ° C. (hereinafter also simply referred to as “(d)”). As the blocking agent for the isocyanato group, one that dissociates from the isocyanato group at 80 to 180 ° C. is used. Here, the blocking agent for the isocyanato group is a compound that can react with the isocyanato group to convert the isocyanato group to another functional group, and can be reversibly converted from another functional group to the isocyanato group by heat treatment. Means.
Examples of the blocking agent that dissociates from an isocyanato group at 80 to 180 ° C. include, for example, malonic acid diester compounds such as dimethyl malonate and diethyl malonate; pyrazole compounds such as 1,2-pyrazole and 3,5-dimethylpyrazole Oxime compounds such as 1,2,4-triazole and methyl ethyl ketoxime; diisopropylamine, caprolactam and the like. These can use only 1 type and can also use multiple types together.
Among the blocking agents, from the viewpoint of dissociation temperature, one or more selected from the group consisting of oxime compounds, pyrazole compounds and malonic acid diester compounds are preferred, from the viewpoint of high storage stability and low temperature thermal crosslinkability, Pyrazole compounds are more preferable, and 3,5-dimethylpyrazole is particularly preferable.

[(E) Other polyol compounds]
As a component to be reacted with (a) and (d), (e) other polyol compounds (hereinafter also simply referred to as “(e)”) other than these are mixed with (b) and (c). be able to.
(E) Other polyol compounds are not particularly limited. For example, polyether polyols, polyester polycarbonate polyols having a number average molecular weight other than 800 to 3,500, and polyester polyols having a number average molecular weight other than 800 to 3,500. And polycarbonate polyols, aliphatic diols, alicyclic diols, aromatic diols, polyfunctional polyols and the like having a number average molecular weight other than 800 to 3,500. Of these, aliphatic diols and alicyclic diols are preferred. Here, among (e) other polyol compounds, a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500, and a number average molecular weight of 800 to The polycarbonate polyol which is 3,500, and an acidic group containing polyol compound are not included.

The proportion of (b) in the total weight of (b) and (c) is preferably 60% by weight to 99% by weight, and 70% by weight from the viewpoint of breaking energy in the tension of the coating film to be formed. More preferably, it is -98 weight%, It is especially preferable that it is 80 weight%-95 weight%.
Further, the proportion of (b) in the total weight of (b) and (e) is preferably from 50% by weight to 100% by weight from the viewpoint of the breaking energy in the tension of the coating film to be formed. More preferably, it is more preferably from 100% by weight to 100% by weight, and particularly preferably from 85% to 100% by weight.

[(A) Polyurethane prepolymer]
(A) The polyurethane prepolymer is at least (a) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polyol having a number average molecular weight of 800 to 3,500. And a polyurethane obtained by reacting a mixture of a polycarbonate polyol having a number average molecular weight of 800 to 3,500, (c) an acidic group-containing polyol compound and (d) a blocking agent for an isocyanato group dissociating at 80 to 180 ° C. It is a prepolymer. As an optional component, (e) other polyol compounds can be reacted together.
(A) It does not restrict | limit especially as a manufacturing method of a polyurethane prepolymer, For example, the following methods are mentioned.
In the first method, (a) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a number average molecular weight of 800 in the presence or absence of a urethanization catalyst. A mixture of a polyester polyol having a molecular weight of ˜3,500 and a polycarbonate polyol having a number average molecular weight of 800 to 3,500, (c) an acidic group-containing polyol compound, and (e) another polyol compound as required. A urethanization reaction was performed, and then (d) a blocking agent was reacted in the presence or absence of a blocking catalyst to perform a blocking reaction, and a part of the terminal isocyanate group was blocked (A) This is a method of synthesizing a polyurethane prepolymer.
In the second method, (a) a polyisocyanate compound and (d) a blocking agent are reacted in the presence or absence of a blocking catalyst to perform a blocking reaction, thereby blocking a part of the isocyanate group. And (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a number average molecular weight of 800 to 3,500 in the presence or absence of a urethanization catalyst. Urethane by reacting a mixture of a certain polyester polyol and a polycarbonate polyol having a number average molecular weight of 800 to 3,500, (c) an acidic group-containing polyol compound, and (e) other polyol compound as required. This is a method of synthesizing (A) polyurethane prepolymer by carrying out a reaction.

The urethanization catalyst is not particularly limited, and examples thereof include salts of metals and organic and inorganic acids such as tin-based catalysts (such as trimethyltin laurylate and dibutyltin dilaurate) and lead-based catalysts (such as lead octylate), and organic Examples thereof include metal derivatives, amine catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, etc.), diazabicycloundecene catalysts, and the like. Among these, dibutyltin dilaurate is preferable from the viewpoint of reactivity.
The blocking catalyst is not particularly limited, and examples thereof include alkali catalysts such as dibutyltin dilaurate and sodium methoxide.
The conditions for the urethanation reaction and the reaction conditions for the blocking reaction are not particularly limited, and can be appropriately selected according to the reactivity of the components used. For example, the reaction conditions for the urethanization reaction can be 3 to 15 hours at a temperature of 50 to 100 ° C. The reaction conditions for the blocking reaction can be 1 to 5 hours at a temperature of 50 to 100 ° C.
The urethanization reaction and the blocking reaction may be performed independently or continuously.

[(B) Chain extender]
(B) The chain extender is not particularly limited as long as it is a compound having two or more functional groups (preferably amino groups, hydroxy groups, etc.) capable of reacting with an isocyanato group. Examples of the chain extender include ethylenediamine, 2-methyl-1,5-pentanediamine, 1,4-butanediamine (tetramethylenediamine), 1,6-hexanediamine, 1,4-hexanediamine, and 3-amino. Alkylene amines such as methyl-3,5,5-trimethylcyclohexylamine, 1,3-bis (aminomethyl) cyclohexane, xylylenediamine, polyamine compounds such as piperazine, 2,5-dimethylpiperazine, diethylenetriamine, triethylenetetramine, Examples thereof include polyol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol, polyalkylene glycols typified by polyethylene glycol, and water. These may be used alone or in combination of two or more. The other chain extender is preferably a primary diamine compound, more preferably an alkylene diamine having two primary amino groups (hereinafter also referred to as “primary alkylene diamine”), and still more preferably. C1-C12 primary alkylene diamine is mentioned, Especially preferably, C5-C9 primary alkylene diamine is mentioned.

  (B) The amount of the chain extender added is preferably equal to or less than the equivalent of the unblocked isocyanato group serving as the chain extension origin in the (A) urethane prepolymer, more preferably the unblocked isocyanato group. 0.7 to 0.99 equivalents. When a chain extender is added below the equivalent of unblocked isocyanato groups, the molecular weight of the chain-extended urethane polymer tends to be suppressed, and the obtained aqueous polyurethane resin dispersion is applied. There exists a tendency for the intensity | strength of the obtained coating film to improve more.

[Method for producing aqueous polyurethane resin dispersion]
The method for producing the aqueous polyurethane resin dispersion is not particularly limited, and for example, it can be produced by the following method.
(A) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polyol having a number average molecular weight of 800 to 3,500 and a number average molecular weight of 800 to 3,500. After the step of obtaining a polyurethane prepolymer by reacting a mixture of polycarbonate polyol, (c) an acidic group-containing polyol compound, (d) a blocking agent, and (e) other polyol compound as required. Through a step of neutralizing acidic groups in the polymer, a step of dispersing the polyurethane prepolymer in an aqueous medium, and a step of reacting the polyurethane prepolymer with a chain extender (B) to obtain an aqueous polyurethane resin dispersion Manufacturing aqueous polyurethane resin dispersions Kill.
In the said manufacturing method, the process of neutralizing an acidic group and the process of disperse | distributing a polyurethane prepolymer in an aqueous medium may be performed separately, and may be performed together.
In the above production method, the chain extender may be added after the polyurethane prepolymer is dispersed in the aqueous medium or during the dispersion.
Each of the above steps may be performed in an inert gas atmosphere or in the air.

[Characteristics of aqueous polyurethane resin dispersion]
In the aqueous polyurethane resin dispersion, the total content of urethane bonds and urea bonds in the aqueous polyurethane resin dispersion is 8 to 15% by weight and 8 to 14% by weight based on the solid content. Is more preferable, 9 to 13.5% by weight is more preferable, and 10 to 13.5% by weight is particularly preferable. Here, the content ratio of the urethane bond means the content ratio of the urethane bond unit (—NHC (═O) O—) in the solid content of the polyurethane resin, and the content ratio of the urea bond is in the solid content of the polyurethane resin. Means the content ratio of the urea bond unit (—NHC (═O) NH—).
When the total content of urethane bonds and urea bonds is less than 8% by weight, the coating film cannot be sufficiently formed, and the coating film surface becomes sticky even after drying. Also, if the total content of urethane bonds and urea bonds exceeds 15% by weight, when the aqueous polyurethane resin dispersion is applied to a substrate, the redispersibility of the paint or coating film in an aqueous solvent is poor. Removal may be difficult and may not be repainted.

The urethane bond content in the aqueous polyurethane resin dispersion is not particularly limited as long as the sum of the urea bond content and the urea bond content is 8 to 15% by weight based on the solid content. The content of urethane bonds in the aqueous polyurethane resin dispersion is preferably 5 to 12% by weight, more preferably 6 to 11% by weight, and 7 to 10% by weight based on the solid content. Particularly preferred.
The content of urea bonds in the aqueous polyurethane resin dispersion is not particularly limited as long as the sum of the content of urethane bonds and the content of urethane bonds is 8 to 15% by weight based on the solid content. The content of urea bonds in the aqueous polyurethane resin dispersion is preferably 2 to 6% by weight, more preferably 2.5 to 5% by weight, based on the solid content, and 2.8 to 4.5. More preferably, it is% by weight.
Here, the content ratio of the urethane bond and the content ratio of the urea bond in the aqueous polyurethane resin dispersion can be calculated from the charged amounts of the respective components when the aqueous polyurethane resin dispersion is prepared. It can also be calculated from the infrared absorption spectrum of the coating film.

In the aqueous polyurethane resin dispersion, the content of carbonate bonds in the aqueous polyurethane resin dispersion is 4 to 23% by weight, more preferably 6 to 20% by weight, more preferably 10 to 20% by weight based on the solid content. It is more preferable that it is 10 to 15% by weight. Here, the content rate of the carbonate bond means the content rate of the carbonate bond unit (—OC (═O) O—) in the solid content of the polyurethane resin. The content of carbonate bonds in the aqueous polyurethane resin dispersion can be calculated from the amount of each component charged when preparing the aqueous polyurethane resin dispersion. It can also be calculated from the infrared absorption spectrum of the coating film.
When the content ratio of the carbonate bond is less than 4% by weight, the breaking energy in tension of the obtained coating film is low. In addition, when the aqueous polyurethane resin dispersion is stored under basic conditions, the tensile strength and breaking energy of the resulting coating film are significantly reduced. Further, when the content ratio of the carbonate bond exceeds 23% by weight, when the water-insoluble organic solvent is mixed, the rate of increase in the viscosity of the aqueous polyurethane resin dispersion increases, so that it cannot be stored as a paint or a coating material composition. .

In the aqueous polyurethane resin dispersion, the content of the ester bond in the aqueous polyurethane resin dispersion is 2 to 16% by weight, more preferably 5 to 15% by weight, more preferably 6 to 12% by weight based on the solid content. It is particularly preferred that Here, the content rate of an ester bond means the content rate of the ester bond unit (-C (= O) O-) in solid content of a polyurethane resin. The ester bond content in the aqueous polyurethane resin dispersion can be calculated from the amount of each component charged when preparing the aqueous polyurethane resin dispersion. It can also be calculated from the infrared absorption spectrum of the coating film.
If the content of the ester bond is less than 2% by weight, when the water-insoluble organic solvent is mixed, the increase rate of the viscosity of the aqueous polyurethane resin dispersion increases, so that it cannot be stored as a paint or coating material composition, The breaking energy in tension of the obtained coating film is low. Moreover, when the content rate of an ester bond exceeds 16 weight%, the fracture | rupture energy in the tension | tensile_strength of the coating film obtained is low. In addition, when the aqueous polyurethane resin dispersion is stored under basic conditions, the resulting coating film has significantly low tensile strength and breaking energy.

In the aqueous polyurethane resin dispersion, the content ratio of the isocyanate group blocked with the blocking agent is 0.2 to 2.0% by weight in terms of solid content and isocyanato group, and 0.3 to 1.5%. More preferably, it is more preferably 0.3 to 1.2% by weight, particularly preferably 0.4 to 1.2% by weight. Here, the content ratio of the blocked isocyanate group means that the content ratio of the blocked isocyanate group in the solid content of the polyurethane resin is calculated as the content ratio of the isocyanate group (—NCO). . The content ratio of blocked isosinato groups in the aqueous polyurethane resin dispersion can be calculated from the charged amount of each component when the aqueous polyurethane resin dispersion is prepared.
When the content ratio of the blocked isocyanate group is less than 0.2% by weight, the adhesion of the obtained coating film to the electrodeposition coating plate surface is poor, and the breaking energy in tension of the resulting coating film is low. Low. On the other hand, when the content ratio of the blocked isocyanate group exceeds 2.0% by weight, the elongation at break of the obtained coating film is small, and only a coating film that is vulnerable to impact can be obtained.

The weight average molecular weight of the polyurethane resin is from 20,000 to 100,000, preferably from 30,000 to 85,000, more preferably from 35,000 to 85,000, Is more preferably from 5,000 to 85,000, particularly preferably from 40,000 to less than 70,000. When the weight average molecular weight of the polyurethane resin is less than 20,000, the elongation at break of the resulting coating film is small, and only a coating film that is vulnerable to impact can be obtained. Further, when the weight average molecular weight of the polyurethane resin exceeds 100,000, when the obtained polyurethane resin dispersion is applied to a substrate, it is difficult to remove because the redispersibility of the paint or coating film in an aqueous solvent is poor. In some cases, repainting cannot be performed.
In particular, when the weight average molecular weight of the polyurethane resin is 40,000 or more and less than 70,000, the swelling rate of the resulting coating film in an aqueous cleaning solution tends to be high, and there is a tendency to be more excellent in detergency. Since the swelling ratio to water is low, the water resistance tends to be excellent.
The weight average molecular weight is measured by gel permeation chromatography (GPC), and is a conversion value obtained from a standard polystyrene calibration curve prepared in advance.

The polyurethane resin contained in the aqueous polyurethane resin dispersion has an alicyclic structure of 7 to 30% by weight based on the solid content, and preferably has an alicyclic structure derived from a polyisocyanate compound.
The content of the alicyclic structure in the aqueous polyurethane resin dispersion is 7 to 30% by weight, more preferably 10 to 25% by weight, and more preferably 12 to 22% by weight based on the solid content. The content is preferably 13 to 20% by weight. When the content of the alicyclic structure in the aqueous polyurethane resin dispersion is less than 7% by weight, the tensile strength of the coating film is lowered and the breaking energy is lowered. In addition, when the content of the alicyclic structure in the aqueous polyurethane resin dispersion exceeds 30% by weight, when the obtained aqueous polyurethane resin dispersion is applied to a substrate, the paint or coating film is redispersed in an aqueous solvent. Since it is inferior in properties, removal may be difficult, and repainting may not be possible.
The content ratio of the alicyclic structure based on the solid content means a portion obtained by removing two hydrogen atoms from cycloalkane or the like. For example, when the alicyclic structure is a cyclohexane ring, the solid content in the aqueous polyurethane resin dispersion 2 shows how many portions (cyclohexane residues) are obtained by removing two hydrogen atoms from cyclohexane.

  The acid value of the aqueous polyurethane resin dispersion is not particularly limited, but is preferably 10 to 32 mgKOH / g, more preferably 13 to 30 mgKOH / g, and particularly preferably 14 to 28 mgKOH / g. . When the acid value of the polyurethane resin dispersion is in the range of 10 to 32 mgKOH / g, the dispersibility in an aqueous medium tends to be further improved, and in particular in the range of 14 to 28 mgKOH / g, the water-insoluble organic When the solvent is mixed, the increase rate of the viscosity of the aqueous polyurethane resin dispersion becomes smaller, and the breaking energy of the coating film can be increased.

  In addition, when two or more types of aqueous polyurethane resin dispersions are used in combination, the content ratio of urethane bonds, urea bonds in the aqueous polyurethane resin dispersion when two or more types of aqueous polyurethane resin dispersions are mixed. Content ratio, urethane bond content ratio and urea bond content ratio, carbonate bond content ratio, ester bond content ratio, isocyanato group content ratio blocked with blocking agent, alicyclic structure content Ratio: weight average molecular weight of polyurethane resin; and acid value of aqueous polyurethane resin dispersion.

〔Neutralizer〕
The aqueous polyurethane resin dispersion preferably contains a neutralizing agent that neutralizes at least some of the acidic groups of the polyurethane resin. The neutralizing agent is used, for example, to neutralize at least some of the acidic groups of the polyurethane prepolymer and disperse the polyurethane prepolymer in the aqueous medium. The aqueous polyurethane resin dispersion is preferably obtained by reacting a polyurethane prepolymer dispersed in an aqueous medium with a chain extender.
Examples of the neutralizing agent include trimethylamine, triethylamine, tri-n-propylamine, tributylamine, triethanolamine, aminomethylpropanol, aminomethylpropanediol, aminoethylpropanediol, trihydroxymethylaminomethane, monoethanolamine, Organic amines such as triisopropanolamine, for example, inorganic alkali salts such as potassium hydroxide and sodium hydroxide, ammonia and the like can be mentioned. These may be used alone or in combination of two or more.
Among the neutralizing agents, organic amines are preferable from the viewpoint of workability, and triethylamine is more preferable.
The addition amount of the neutralizing agent is, for example, 0.4 to 1.2 equivalents, preferably 0.6 to 1.0 equivalents per equivalent of acidic groups of the polyurethane prepolymer.

[Optional ingredients]
In the aqueous polyurethane resin dispersion, amino alcohol, monoalcohol and / or monoamine can be reacted with the polyurethane prepolymer as an optional component.
An amino alcohol can introduce | transduce a hydroxyl group into the molecular terminal of a polyurethane prepolymer, for example by making it react with a polyurethane prepolymer in the state to which the (A) polyurethane prepolymer was disperse | distributed to water. Thereby, further chain extension can be performed by reaction with the isocyanate group generated by deblocking when the coating film is dried by heating. Thus, the elasticity modulus of a coating film improves by raising the crosslinking degree of the polyurethane resin which forms a coating film. The amount of amino alcohol added is preferably 0% by weight or more and less than 2% by weight, more preferably 0% by weight or more and less than 1% by weight, based on the solid content of the aqueous polyurethane resin dispersion.
Specific examples of the amino alcohol include ethanolamine, butanolamine, hexanolamine, and the like, and ethanolamine is preferred from the viewpoint of good water dispersibility.

  Moreover, the molecular terminal of a polyurethane prepolymer can be made non-reactive by reacting monoalcohol or monoamine. Thereby, the crosslinking degree of the polyurethane resin which forms a coating film can be made low, As a result, the elasticity modulus of a coating film can be reduced. The addition amount of monoalcohol and monoamine is preferably 0% by weight or more and less than 2% by weight, more preferably 0% by weight or more and less than 1% by weight, based on the solid content of the aqueous polyurethane resin.

Examples of the monoalcohol include ethanol, n-propanol, isopropanol, n-butanol, hexanol, octanol, and the like, and n-butanol is more preferable from the viewpoint of easy production of the aqueous polyurethane resin dispersion.
Examples of the monoamine include ethylamine, n-propylamine, isopropylamine, n-butylamine, and n-hexylamine.

From the viewpoint of good reactivity, the monoalcohol is preferably added and reacted in the production of the (A) polyurethane prepolymer. Moreover, when making monoalcohol react, it is preferable to carry out in the state heated at 60 degreeC or more from the point with favorable reactivity.
The monoamine is preferably used after (A) the polyurethane prepolymer is dispersed in an aqueous medium, and is preferably added and reacted before the (B) chain extender is added. Moreover, when making monoamine react, it is preferable to carry out in the state controlled to 60 degrees C or less from the point which can suppress a side reaction.

[Aqueous medium]
The polyurethane resin is dispersed in an aqueous medium. Examples of the aqueous medium include water, a mixed medium of water and a hydrophilic organic solvent, and the like.
Examples of water include clean water, ion-exchanged water, distilled water, and ultrapure water. However, in view of availability and influence of salt, polyurethane resin particles are preferably unstable. Exchange water is mentioned.

Examples of hydrophilic organic solvents include lower monohydric alcohols such as methanol, ethanol, and propanol; polyhydric alcohols such as ethylene glycol and glycerin; N-methylmorpholine, dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone, and N-ethyl. Examples include aprotic hydrophilic organic solvents such as pyrrolidone, dipropylene glycol dimethyl ether (DMM), and β-alkoxypropionic acid amide.
The amount of the hydrophilic organic solvent in the aqueous medium is preferably 0 to 20% by weight, and more preferably 0 to 10% by weight.

The coating film obtained by applying the aqueous polyurethane resin dispersion is excellent in water resistance and solvent resistance, and is excellent in adhesion to the electrodeposition coating film.
There are two types of electrodeposition coatings, anionic and cationic. Generally, the cationic type uses a modified epoxy resin as a base resin and is crosslinked with isocyanate, whereas the anionic type is crosslinked by oxidative polymerization. In the cationic type, the secondary hydroxyl group generated by the ring opening of the epoxy group remains, and in the anionic type, the carboxyl group is introduced. Therefore, the blocking agent is dissociated in the heating and drying step of the aqueous polyurethane resin dispersion. It is thought that it causes a crosslinking reaction with the free isocyanato group formed by Such electrodeposition coatings are used in heavy machinery, industrial machinery such as agricultural machinery, vehicles such as automobiles and bicycles, building materials such as prefabricated steel frames, fire doors and sashes, electrical equipment such as switchboards, elevators, and microwave ovens. Yes.

The aqueous polyurethane resin dispersion can be applied, for example, on a base material on which an electrodeposition coating film is formed by using an application device or the like and baked at a temperature of 80 to 250 ° C. A drying step can also be provided before the baking step. Moreover, a preheating process can also be provided between a drying process and a baking process.
When the applied aqueous polyurethane resin dispersion is baked, the blocking agent of the blocked isocyanate group is dissociated to form a cross-linked structure with an acidic group or other isocyanate group. A coating film having high hardness can be formed.
A general method can be used for the baking process and the drying process.

[Coating material composition]
As the coating material composition, an aqueous polyurethane resin dispersion may be used as it is, or various additives may be added to prepare a coating material composition. One type of aqueous polyurethane resin dispersion may be used alone, or a plurality of types may be used in combination.
Additives include plasticizers, antifoaming agents, leveling agents, fungicides, rust inhibitors, matting agents, flame retardants, tackifiers, thixotropic agents, lubricants, antistatic agents, thinning agents, thickening agents Agents, diluents, pigments, dyes, ultraviolet absorbers, light stabilizers, antioxidants, fillers and the like.
The coating material composition can be applied to coating (film formation) on various substrates such as metal, ceramic, synthetic resin, nonwoven fabric, woven fabric, knitted fabric, and paper.

[Polyurethane resin film]
A polyurethane resin film (hereinafter also referred to as “polyurethane film”) is produced by heating and drying an aqueous polyurethane resin dispersion or a composition containing an aqueous polyurethane resin dispersion.
The composition containing the aqueous polyurethane resin dispersion can be prepared by adding various additives to the aqueous polyurethane resin dispersion. Examples of the additive include the components exemplified in the coating material composition.

  The method for producing the polyurethane resin film is not particularly limited. For example, the aqueous polyurethane resin dispersion is applied on a releasable substrate using various coating apparatuses, and then dried, and then the substrate with the polyurethane resin film is used. After obtaining, the method of peeling the said mold release base material and the said polyurethane resin film is mentioned.

Although it does not restrict | limit especially as a peelable base material, For example, the base material which carried out the release agent process on the surfaces, such as glass, plastics, such as a polyethylene terephthalate and polytetrafluoroethylene, and a metal.
The coating device is not particularly limited, and examples thereof include a bar coater, a roll coater, a gravure roll coater, and an air spray.

  The thickness of the polyurethane resin film is not particularly limited, but is preferably 0.01 mm to 0.5 mm.

Next, the present invention will be described in more detail with reference to examples and comparative examples.
The physical properties were measured as follows.
(1) Hydroxyl value: Measured according to JIS K 1557 method B.
(2) Free isocyanate group content: 0.5 g of the reaction mixture after completion of the urethanization reaction was sampled and added to a mixed solution of 0.1 mL / L (liter) of dibutylamine-tetrahydrofuran (THF) solution and 10 mL of THF. Then, unconsumed dibutylamine was titrated with 0.1 mol / L hydrochloric acid. From the difference between the titration value and the blank experiment, the molar concentration of the isocyanate group remaining in the reaction mixture was calculated. The molar concentration was converted to the weight fraction of isocyanato groups to obtain the free isocyanate group content. The indicator used for titration is bromophenol blue.
(3) Acid value: 100 g of the aqueous polyurethane resin dispersion was diluted 10 times with pure water, and 10 g of acetic acid was mixed and stirred at room temperature. The precipitated solid was filtered with a 120 mesh stainless steel wire mesh. 600 g of water was poured into the obtained solid, stirred for 30 minutes at room temperature and allowed to stand, and then the solid was filtered through a 120-mesh stainless wire mesh. The same operation was repeated 5 times. After the remaining solid was dried at 60 ° C. for 24 hours, the acid value was measured according to the indicator titration method of JIS K 1557. (4) Content based on solid content of urethane bond (urethane bond content), Content based on solid content of urea bond (urea bond content): Urethane bond and urea bond based on charge ratio of each raw material of aqueous polyurethane resin dispersion The molar concentration (mol / g) was calculated and expressed as a weight fraction. The weight fraction was based on the solid content of the aqueous polyurethane resin dispersion. An aqueous polyurethane resin dispersion (0.3 g) was applied to a glass substrate with a thickness of 0.2 mm, and the weight remaining after heating and drying at 140 ° C. for 4 hours was measured. The partial concentration was used. The weight fraction was calculated using the product of the total weight of the aqueous polyurethane resin dispersion and the solid content concentration as the solid content weight.
(5) Content based on solid content of carbonate bond (carbonate bond content): The carbonate bond molar concentration (mol / g) was calculated from the charge ratio of each raw material of the aqueous polyurethane resin dispersion and converted into a weight fraction. Was written. The weight fraction was calculated based on the solid content of the aqueous polyurethane resin dispersion by the same method as the content of the urethane bond based on the solid content.
(6) Content based on solid content of ester bond (ester bond content): The molar concentration (mol / g) of the ester bond was calculated from the charge ratio of each raw material of the aqueous polyurethane resin dispersion, and was converted into the weight fraction. The thing was written. The weight fraction was calculated based on the solid content of the aqueous polyurethane resin dispersion by the same method as the content of the urethane bond based on the solid content.
(7) Content based on solid content of alicyclic structure (alicyclic structure content): The weight fraction of the alicyclic structure calculated from the charged ratio of each raw material of the aqueous polyurethane resin dispersion was described. The weight fraction was calculated based on the solid content of the aqueous polyurethane resin dispersion by the same method as the content of the urethane bond based on the solid content.
(8) Weight average molecular weight of the polyurethane resin in the aqueous polyurethane resin dispersion: measured by gel permeation chromatography (GPC), and a conversion value obtained from a standard polystyrene calibration curve prepared in advance was described.
(9) Content of isocyanato group to which blocking agent based on solid content in aqueous polyurethane resin dispersion is bound (in terms of isocyanato group, blocked NCO content): the molar amount charged of blocking agent is converted to the weight of isocyanato group And the ratio divided by the solid content weight of the aqueous polyurethane resin dispersion. The solid content weight of the aqueous polyurethane resin dispersion was calculated by the same method as the content based on the solid content of the urethane bond.

(10) Swelling ratio of coating film to water: 0.3 mL of aqueous polyurethane resin dispersion was applied on a glass plate at a thickness of 72 μm (bar coater # 36) until the solid content concentration of the coating film reached 90%. Heat drying at 50 ° C. This coating film was immersed in ion exchange water at 28 ° C. for 6 hours, and the coating film weight before and after immersion was measured. The swelling ratio of the coating film into water was calculated by the following formula. The solid content concentration of the dried coating film was calculated by the same method as the content ratio of the urethane bond based on the solid content.
(Swelling ratio) = [(weight of coating film after water immersion) − (weight of coating film before water immersion)] / (weight of coating film before water immersion) × 100
(11) Swelling ratio of dry coating film to aqueous cleaning solution: Aqueous cleaning solutions containing 5%, 4%, 1% and 90% of butyl cellosolve, isopropanol, dimethylethanolamine and ion-exchanged water on a weight basis were prepared. . An aqueous polyurethane resin dispersion (0.3 mL) was coated on a glass plate at a thickness of 72 μm (bar coater # 36), and dried by heating at 50 ° C. until the solid content concentration of the coating film reached 90%. This coating film was immersed in an aqueous cleaning solution at 28 ° C. for 15 seconds, and the coating film weight before and after immersion was measured. The swelling ratio of the coating film into the aqueous cleaning solution was calculated by the following formula. The solid content concentration of the dried coating film was calculated by the same method as the content ratio of the urethane bond based on the solid content.
(Swelling ratio) = [(weight of coating film after immersion in aqueous cleaning liquid) − (weight of coating film before immersion in aqueous cleaning liquid)] / (weight of coating film before immersion in aqueous cleaning liquid) × 100
(12) Elastic modulus, tensile strength, elongation at break of polyurethane resin film: Measured by a method based on JIS K 7311. The measurement conditions were a measurement temperature of 23 ° C., a humidity of 50%, and a tensile speed of 100 mm / min.
(13) Breaking energy: It was determined by integrating the stress from the elongation zero of the elongation-stress curve to the elongation at break.
(14) Adhesiveness to the electrodeposited base material: An aqueous polyurethane resin dispersion was applied in a thickness of 0.2 mm on an automobile steel plate cationic electrodeposition coating plate (manufactured by Nippon Test Panel Co., Ltd.), and at 120 ° C. for 3 hours. The film was dried by heating at 140 ° C. for 30 minutes, and a cross-cut peel test was performed using the obtained coating film. The coating is cut at an interval of 1 mm vertically and horizontally in an area of 5 mm x 5 mm, and after sticking an adhesive tape, the number of cells remaining on the surface of the electrodeposited substrate when peeled off is visually evaluated. did. For example, the case where 15 of 25 remained was described as 15/25.
(15) Increase rate of viscosity when 2-ethylhexanol was added: 3 g of 2-ethylhexanol was added to 100 g of the aqueous polyurethane resin dispersion, and the mixture was stirred at 20 ° C. for 5 minutes. The viscosity was measured after standing at the same temperature for 10 minutes, and the increase rate (%) of the viscosity before and after the addition of 2-ethylhexanol was calculated.
(16) Storage stability under basic conditions: Triethylamine was added to the aqueous polyurethane resin dispersion to adjust the pH to 11, and stored at 60 ° C. for 7 days. Using this as a polyurethane resin film, the tensile strength was measured by the methods (12) and (13), and the breaking energy was calculated. The rate of change in tensile strength and breaking energy before and after storage was calculated.

[Example 1]
[Production of aqueous polyurethane resin dispersion (1)]
In a reaction vessel into which a stirrer, a reflux condenser and a thermometer were inserted, ETERNCOLLU UHC50-200 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries; number average molecular weight 1975; hydroxyl value 56.8 mgKOH / g; 1,6-hexanediol, 311 g of polyester polycarbonate diol obtained by reacting dimethyl carbonate and ε-caprolactone), 22.0 g of 2,2-dimethylolpropionic acid (DMPA) and 159 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream. 147 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.39 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 9.62 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.01% by weight. 603 g was extracted from the mixture obtained by adding and mixing 16.9 g of triethylamine to the reaction mixture, and added to 850 g of water under strong stirring. Next, 44.0 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (1).

[Production of polyurethane film (A)]
The aqueous polyurethane resin dispersion (1) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (A). The film thickness of the obtained polyurethane film (A) was 0.15 mm.

[Example 2]
[Production of aqueous polyurethane resin dispersion (2)]
In the same reaction vessel as in Example 1, ETERRNACOLL UHC50-200 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries, Ltd .; number average molecular weight 1989; hydroxyl value 56.4 mgKOH / g; 1,6-hexanediol, dimethyl carbonate and ε- 218 g of polyester polycarbonate diol obtained by reacting caprolactone), 25.7 g of 2,2-dimethylolpropionic acid (DMPA) and 125 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream. 135 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.31 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 9.14 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.52% by weight. 505 g was extracted from the mixture obtained by adding and mixing 23.3 g of triethylamine to the reaction mixture, and added to 690 g of water under strong stirring. Then, 45.7 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction to obtain an aqueous polyurethane resin dispersion (2).

[Production of polyurethane film (B)]
The aqueous polyurethane resin dispersion (2) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (B). The film thickness of the obtained polyurethane film (B) was 0.15 mm.

[Example 3]
[Production of aqueous polyurethane resin dispersion (3)]
In the same reaction vessel as in Example 1, ETERNACOLL UHC50-200 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries; number average molecular weight 1975; hydroxyl value 56.8 mgKOH / g; 1,6-hexanediol, dimethyl carbonate and ε- 250 g of polyester polycarbonate diol obtained by reacting caprolactone), 20.2 g of 2,2-dimethylolpropionic acid (DMPA) and 80.0 g of N-ethylpyrrolidone (NEP) were charged under a nitrogen stream. 125 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.33 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 5 hours. Thereafter, 8.18 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.28% by weight. 446 g was extracted from the mixture obtained by adding and mixing 18.1 g of triethylamine to the reaction mixture, and added to 730 g of water under strong stirring. Subsequently, 39.3 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (3).

[Production of polyurethane film (C)]
The aqueous polyurethane resin dispersion (3) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and at 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (C). The film thickness of the obtained polyurethane film (C) was 0.15 mm.
[Example 4]

[Production of aqueous polyurethane resin dispersion (4)]
In the same reaction vessel as in Example 1, ETERNACOLL UHC50-200 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries; number average molecular weight 2014; hydroxyl value 55.7 mgKOH / g; 1,6-hexanediol, dimethyl carbonate and ε- 252 g of polyester polycarbonate diol obtained by reacting caprolactone), 20.0 g of 2,2-dimethylolpropionic acid (DMPA) and 80.3 g of N-ethylpyrrolidone (NEP) were charged under a nitrogen stream. 123 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.33 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 8.15 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The content of free NCO groups at the end of the urethanization reaction was 2.24% by weight. 444 g was extracted from the mixture obtained by adding and mixing 18.1 g of triethylamine to the reaction mixture, and added to 740 g of water under strong stirring. Then, 6.41 g of 35 wt% ethanolamine (EA) aqueous solution and 32.5 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution were added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (4). .

[Production of polyurethane film (D)]
The aqueous polyurethane resin dispersion (4) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (D). The film thickness of the obtained polyurethane film (D) was 0.15 mm.

[Example 5]
[Production of aqueous polyurethane resin dispersion (5)]
In the same reaction vessel as in Example 1, ETERNACOLL UHC50-300 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries; number average molecular weight 2976; hydroxyl value 37.7 mgKOH / g; 1,6-hexanediol, dimethyl carbonate and ε- 250 g of polyester polycarbonate diol obtained by reacting caprolactone), 27.2 g of 2,2-dimethylolpropionic acid (DMPA) and 137 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream. 127 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.34 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 8.45 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.05% by weight. 526 g was extracted from the mixture obtained by adding and mixing 24.6 g of triethylamine to the reaction mixture, and added to 720 g of water under strong stirring. Subsequently, 38.6 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (5).

[Production of polyurethane film (E)]
The aqueous polyurethane resin dispersion (5) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (E). The film thickness of the obtained polyurethane film (E) was 0.15 mm.

[Comparative Example 1]
[Production of aqueous polyurethane resin dispersion (6)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2000; hydroxyl value 56.1 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 272 g, 2,2-dimethylolpropionic acid (DMPA) 18.5 g and N-methylpyrrolidone (NMP) 176 g were charged under a nitrogen stream. 125 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.33 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 10.4 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The content ratio of free isocyanate groups at the end of the urethanization reaction was 1.78% by weight. 564 g was extracted from the mixture obtained by adding and mixing 13.9 g of triethylamine to the reaction mixture, and added to 870 g of water under strong stirring. Subsequently, 36.5 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (6).

[Production of polyurethane film (F)]
The aqueous polyurethane resin dispersion (6) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (F). The film thickness of the obtained polyurethane film (F) was 0.15 mm.

[Comparative Example 2]
[Production of aqueous polyurethane resin dispersion (7)]
In the same reaction vessel as in Example 1, ETERNACOLL UHC50-200 (registered trademark; polyester polycarbonate diol manufactured by Ube Industries; number average molecular weight 2014; hydroxyl value 55.7 mgKOH / g; 1,6-hexanediol, dimethyl carbonate and ε- 205 g of polyester polycarbonate diol obtained by reacting caprolactone, 16.9 g of 2,2-dimethylolpropionic acid (DMPA) and 81.3 g of N-ethylpyrrolidone (NEP) were charged under a nitrogen stream. 109 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.30 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 5 hours to obtain a polyurethane prepolymer. . The free NCO group content at the end of the urethanization reaction was 2.88% by weight. 386 g was extracted from the mixture obtained by adding and mixing 18.1 g of triethylamine to the reaction mixture, and added to 620 g of water under strong stirring. Subsequently, 14.7 g of 35 wt% ethanolamine (EA) aqueous solution and 25.7 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution were added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (7). .

[Production of polyurethane film (G)]
The aqueous polyurethane resin dispersion (7) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (G). The film thickness of the obtained polyurethane film (G) was 0.15 mm.

[Comparative Example 3]
[Production of aqueous polyurethane resin dispersion (8)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2025; hydroxyl value 55.4 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 69.9 g, polypropylene glycol (number average molecular weight 2000; hydroxyl value 56.1 mg KOH / g) 69.1 g, 2,2-dimethylolpropionic acid (DMPA) 9.19 g and N-methylpyrrolidone (NMP) 69.4 g was charged under a nitrogen stream. 64.2 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.17 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 5 hours. Thereafter, 5.50 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The content ratio of free isocyanate groups at the end of the urethanization reaction was 1.97% by weight. 269 g was extracted from the mixture obtained by adding and mixing 7.08 g of triethylamine to the reaction mixture, and added to 360 g of water under strong stirring. Subsequently, 19.9 g of a 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction to obtain an aqueous polyurethane resin dispersion (8).

[Manufacture of polyurethane film (H)]
The aqueous polyurethane resin dispersion (8) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (H). The film thickness of the obtained polyurethane film (H) was 0.15 mm.

[Comparative Example 4]
[Production of aqueous polyurethane resin dispersion (9)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2000; hydroxyl value 56.1 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 261 g, 2,2-dimethylolpropionic acid (DMPA) 13.3 g and N-methylpyrrolidone (NMP) 124 g were charged under a nitrogen stream. Thereafter, the mixture was heated and stirred at 60 ° C. to confirm that DMPA was dissolved. 104 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.35 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours to obtain a polyurethane prepolymer. The free isocyanate group content at the end of the urethanization reaction was 2.44% by weight. The reaction mixture was cooled to 80 ° C., 475 g was extracted from the mixture obtained by adding and mixing 12.0 g of triethylamine, and added to 713 g of water under strong stirring. Subsequently, 25.1 g of 35% by weight diethylenetriamine (DETA) aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (9).

[Production of polyurethane film (I)]
The aqueous polyurethane resin dispersion (9) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (I). The film thickness of the obtained polyurethane film (I) was 0.15 mm.

[Example 6]
[Production of aqueous polyurethane resin dispersion (10)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1982; hydroxyl value 56.6 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. 91.3 g of the obtained polycarbonate diol), poly (1,6-hexanediol adipate) (number average molecular weight 1993; hydroxyl value 56.3 mg KOH / g; obtained by reacting 1,6-hexanediol and adipic acid Polyester diol) 113 g, 2,2-dimethylolpropionic acid (DMPA) 24.0 g and N-methylpyrrolidone (NMP) 118 g were charged under a nitrogen stream. 127 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.28 g of dibutyltin dilaurate (catalyst) were added and heated to 80 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 7.40 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.53% by weight. 443 g was extracted from the mixture obtained by adding and mixing 21.7 g of triethylamine to the reaction mixture, and added to 610 g of water under strong stirring. Then, 40.5 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (10).

[Production of polyurethane film (J)]
The aqueous polyurethane resin dispersion (10) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (J). The film thickness of the obtained polyurethane film (J) was 0.15 mm.

[Example 7]
[Production of aqueous polyurethane resin dispersion (11)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1968; hydroxyl value 57.0 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. 107 g of the obtained polycarbonate diol), poly (1,6-hexanediol adipate) (number average molecular weight 1993; hydroxyl value 56.3 mg KOH / g; polyester diol obtained by reacting 1,6-hexanediol and adipic acid ) 46.2 g, 2,2-dimethylolpropionic acid (DMPA) 18.4 g and N-methylpyrrolidone (NMP) 87.7 g were charged under a nitrogen stream. 94.5 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.21 g of dibutyltin dilaurate (catalyst) were added and heated to 80 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 5.36 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.38% by weight. 335 g was extracted from the mixture obtained by adding and mixing 13.6 g of triethylamine to the reaction mixture, and added to 460 g of water under strong stirring. Then, 28.6 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (11).

[Manufacture of polyurethane film (K)]
The aqueous polyurethane resin dispersion (11) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (K). The film thickness of the obtained polyurethane film (K) was 0.15 mm.

[Example 8]
[Production of aqueous polyurethane resin dispersion (12)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1968; hydroxyl value 57.0 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Obtained polycarbonate diol) 45.7 g, poly (1,6-hexanediol adipate) (number average molecular weight 1993; hydroxyl value 56.3 mg KOH / g; obtained by reacting 1,6-hexanediol and adipic acid Polyester diol) 106 g, 2,2-dimethylolpropionic acid (DMPA) 17.7 g, and N-methylpyrrolidone (NMP) 86.7 g were charged under a nitrogen stream. 93.0 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.22 g of dibutyltin dilaurate (catalyst) were added and heated to 80 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 5.27 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 1.5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.69% by weight. 333 g was extracted from the mixture obtained by adding and mixing 21.8 g of triethylamine to the reaction mixture, and added to 450 g of water under strong stirring. Subsequently, 32.6 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (12).

[Production of polyurethane film (L)]
The aqueous polyurethane resin dispersion (12) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (L). The film thickness of the obtained polyurethane film (L) was 0.15 mm.

[Example 9]
[Production of aqueous polyurethane resin dispersions (13) and (14)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2022; hydroxyl value 55.5 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. The obtained polycarbonate diol (152 g), 2,2-dimethylolpropionic acid (DMPA) (17.7 g) and N-methylpyrrolidone (NMP) (86.7 g) were charged under a nitrogen stream. 93.0 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.22 g of dibutyltin dilaurate (catalyst) were added and heated to 80 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 5.23 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.61% by weight. 331 g was extracted from the mixture obtained by adding and mixing 13.1 g of triethylamine to the reaction mixture, and added to 450 g of water under strong stirring. Subsequently, 31.2 g of 35% by weight 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (13). 33.3 g of the aqueous polyurethane resin dispersion (11) and 66.6 g of the aqueous polyurethane resin dispersion (13) were mixed to obtain an aqueous polyurethane resin dispersion (14).

[Production of polyurethane film (M)]
The aqueous polyurethane resin dispersion (14) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (M). The film thickness of the obtained polyurethane film (M) was 0.15 mm.

[Comparative Example 5]
[Production of aqueous polyurethane resin dispersion (15)]
It was obtained by reacting poly (1,6-hexanediol adipate) (number average molecular weight 1993; hydroxyl value 56.3 mgKOH / g; 1,6-hexanediol and adipic acid in the same reaction vessel as in Example 1. Polyester diol) 206 g, 2,2-dimethylolpropionic acid (DMPA) 24.3 g, and N-methylpyrrolidone (NMP) 119 g were charged under a nitrogen stream. 127 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.30 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 5 hours. Thereafter, 7.55 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 1.5 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 2.55% by weight. 480 g was extracted from the mixture obtained by adding and mixing 21.9 g of triethylamine to the reaction mixture, and added to 660 g of water under strong stirring. Then, 41.0 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (15).

[Production of polyurethane film (N)]
The aqueous polyurethane resin dispersion (15) was applied as a coating material composition on a glass plate and dried at 120 ° C. for 3 hours and 140 ° C. for 30 minutes to obtain a good coating layer. The obtained coating layer was peeled off to produce a polyurethane film (N). The film thickness of the obtained polyurethane film (N) was 0.15 mm.

  Urethane bond content of aqueous polyurethane resin dispersions obtained in Examples and Comparative Examples, urea bond content, carbonate bond content, ester bond content, weight average molecular weight, alicyclic structure content, Table 1 shows the acid value and the content ratio of the blocked isocyanate group (in terms of isocyanate group). Water swelling ratio of coating film of aqueous polyurethane resin dispersion obtained in Examples and Comparative Examples, swelling ratio in washing water, breaking energy of coating film, results of adhesion test on electrodeposition surface and 2-ethylhexanol Table 2 shows the rate of increase in viscosity at the time of addition. Table 2 shows the tensile properties of the polyurethane films obtained in the examples and comparative examples. In addition, about Example 9, it is a value about an aqueous polyurethane resin dispersion (14).

UHC50-200: ETERRNACOLL UHC50-200 (manufactured by Ube Industries)
UHC50-300: ETERRNACOLL UHC50-300 (manufactured by Ube Industries)
UH-200: ETERRNACOLL UH-200 (manufactured by Ube Industries)
HD-AA-2000: poly (1,6-hexanediol adipate)
PPG2000: Polypropylene glycol DMPZ: 3,5-dimethylpyrazole EA: Ethanolamine DETA: Diethylenetriamine

*: Measurement is not possible because no film remains.

In Examples 1 to 9, when 2-ethylhexanol was added to the aqueous polyurethane resin dispersion, the rate of increase in viscosity was small, the adhesion to the electrodeposited substrate was excellent, and the breaking energy in tension was A high coating film was obtained.
In Comparative Example 1, a polycarbonate polyol having a carbonate bond content exceeding 23% by weight and an ester bond content of 0% by weight is used. When 2-ethylhexanol was added to the aqueous polyurethane resin dispersion of Comparative Example 1, the rate of increase in viscosity was significantly increased.
In Comparative Example 2, a polyester polycarbonate polyol having a blocked isocyanate content of 0% by weight is used. In Comparative Example 2, a coating film having poor adhesion to an electrodeposited substrate and low rupture energy in tension was obtained.
In Comparative Example 3, a polycarbonate polyol having a carbonate bond content of 23% by weight or less and an ester bond content of 0% by weight is used. In Comparative Example 3, a coating film having a low breaking energy in tension was obtained.
In Comparative Example 4, a polycarbonate polyol having a carbonate bond content exceeding 23% by weight is used. Moreover, the crosslinked structure by a polyamine compound is introduce | transduced, and the weight average molecular weight of a polyurethane resin is over 100,000. In Comparative Example 4, when 2-ethylhexanol was added to the polyurethane resin dispersion, the rate of increase in viscosity was increased, and a coating film having low tensile breaking energy was obtained. Furthermore, in Comparative Example 4, a coating film having a low elongation at break in tension was obtained.
In Comparative Example 5, a polyester polyol having an ester bond content of more than 16% by weight and a carbonate bond content of 0% by weight is used. In Comparative Example 5, a coating film having a low breaking energy in tension was obtained. Moreover, when the aqueous polyurethane resin dispersion of Comparative Example 5 was stored under basic conditions, the rate of decrease in tensile strength and the rate of decrease in rupture energy in tension of the resulting coating film were remarkably large.

  The aqueous polyurethane resin dispersion of the present invention can be widely used as a raw material for paints and coating materials.

Claims (6)

  At least (a) a polyisocyanate compound, (b) a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500 and a number average molecular weight of 800 to 3,500. A polycarbonate polyol having a number average molecular weight of 800 to 3,500, a polyester polyol having a number average molecular weight of 800 to 3,500, and / or a number average molecular weight of 800 to 3, (A) a polyurethane prepolymer obtained by reacting a mixture with a polycarbonate polyol of 500, (c) an acidic group-containing polyol compound, and (d) a blocking agent for an isocyanato group dissociating at 80 to 180 ° C., Polyureta The polyurethane resin obtained by reacting the (B) chain extender having reactivity with the isocyanato group of the prepolymer is dispersed in an aqueous medium, and the total content of urethane bonds and urea bonds Is 8 to 15% by weight based on the solid content, the carbonate bond content is 4 to 23% by weight based on the solid content, the ester bond content is 2 to 16% by weight based on the solid content, The ring structure content ratio is 7 to 30% by weight based on the solid content, and the content ratio of the isocyanate group to which the blocking agent is bound is 0.2 to 2.0% by weight based on the solid content and in terms of the isocyanate group, An aqueous polyurethane resin dispersion having a weight average molecular weight of 20,000 to 100,000.   The aqueous polyurethane resin dispersion according to claim 1, wherein the acid value is 10 to 32 mg KOH / g.   The aqueous polyurethane resin dispersion according to claim 1 or 2, wherein the (a) polyisocyanate compound is an alicyclic diisocyanate.   (D) The aqueous polyurethane resin dispersion according to any one of claims 1 to 3, wherein the blocking agent is at least one selected from the group consisting of an oxime compound, a pyrazole compound, and a malonic ester compound. .   The coating material composition containing the water-based polyurethane resin dispersion as described in any one of Claims 1-4.   The polyurethane resin film manufactured by heat-drying the composition containing the water-based polyurethane resin dispersion as described in any one of Claims 1-4.