JPWO2015194671A1 - Aqueous polyurethane resin dispersion - Google Patents

Abstract

The present invention provides a polyurethane resin obtained by reacting a polyisocyanate, a polyol, an acidic group-containing polyol, a hydroxyalkanoic acid, and a blocking agent for an isocyanato group with a chain extender. An aqueous polyurethane resin dispersion dispersed in an aqueous medium, wherein the polyol includes a polycarbonate polyol and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500, and the polyurethane resin includes a urethane bond and a urea. The total bond is 6 to 20% by weight based on solid content, the carbonate bond is 10 to 40% by weight based on solid content, the blocked isocyanate group is 0.2 to 2.0% by weight based on solid content, and the weight average molecular weight is Aqueous polyureta that is 20,000-150,000 It relates to a resin dispersion.

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, and the like, and can reduce volatile organic substances compared to conventional organic solvent-based polyurethane. Therefore, it is a material that is being replaced by organic 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 ( Non-patent document 1). Also, it is known that a coating film obtained by applying an aqueous urethane resin dispersion using polycarbonate polyol as a raw material is excellent in light resistance, heat resistance, hydrolysis resistance, oil resistance, and the like (Patent Document 1). reference).

  As described above, an aqueous polyurethane resin dispersion using a polycarbonate polyol exhibits good characteristics, but is not sufficient as compared with an organic 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 (Patent Document 2 and Patent Document 3). reference). It is also known that an aqueous polyurethane resin dispersion using a polycarbonate polyol as a raw material has a feature of high adhesion to an electrodeposition coating film (see 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 re-dispersed in water, and the coating obtained by applying and heat treatment is excellent in water resistance and solvent resistance, and is excellent in adhesion to the electrodeposition coating film. It has been found that since the breaking energy in tension is high, the impact resistance is also excellent (see 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, sufficient adhesion to the substrate and large breaking energy in tension may not be obtained. Further, when the water-insoluble organic solvent is added, the viscosity is remarkably increased, so that there is a problem in the storage stability as a paint or a coating material composition. When a water-insoluble organic solvent is added to an aqueous polyurethane resin dispersion in order to mix an additive that is difficult to disperse in water by the method described in Patent Document 6, the viscosity of the aqueous polyurethane resin dispersion increases. There are problems such as poor handling and poor discharge when spraying. Even if a water-insoluble organic solvent is added by the method described in Patent Document 7, the thickening of the aqueous polyurethane resin dispersion can be suppressed, but since the rupture energy of the coating film is reduced, it is weak against impact. There was a problem.

  The subject of the present invention is that the viscosity does not increase remarkably even when a water-insoluble organic solvent is added, and when the film is formed on the substrate, a large breaking energy in tension and excellent adhesion to the substrate can be achieved. An aqueous polyurethane resin dispersion is provided. Furthermore, the subject of this invention is providing the water-based polyurethane resin dispersion which gives the coating film with the low water swelling rate and the high swelling rate to an aqueous cleaning liquid.

The present invention has been made to solve the above problems, and specifically has the following configuration.
[1] A blocking agent for (a) a polyisocyanate compound, (b) a polyol compound, (c) an acidic group-containing polyol compound, (d) a hydroxyalkanoic acid, and (e) an isocyanato group that dissociates at 80 to 180 ° C. The polyurethane resin obtained by reacting (A) the polyurethane prepolymer obtained by the reaction with the (B) chain extender having reactivity with the isocyanate group of the polyurethane prepolymer is dispersed in an aqueous medium. An aqueous polyurethane resin dispersion comprising:
The (b) polyol compound includes a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500,
The polyurethane resin has a total content of urethane bonds and urea bonds of 6 to 20% by weight based on solid content, and a content of carbonate bonds of 10 to 40% by weight based on solid content, An aqueous polyurethane resin dispersion in which the content of the isocyanate group to which the blocking agent is bonded is 0.2 to 2.0% by weight in terms of solid content and isocyanato group, and the weight average molecular weight is 20,000 to 150,000. body.
[2] The aqueous polyurethane resin dispersion according to [1], wherein the acid value is 10 to 40 mg KOH / g and the acid value derived from the molecular end is 3 to 30 mg KOH / g.
[3] The aqueous polyurethane resin dispersion according to [1] or [2], wherein (a) the polyisocyanate compound is an alicyclic diisocyanate.
[4] The aqueous polyurethane resin dispersion according to any one of [1] to [3], wherein (d) the hydroxyalkanoic acid has 2 to 30 carbon atoms.
[5] The aqueous polyurethane resin dispersion according to any one of [1] to [4], wherein the content of the alicyclic structure is 6 to 30% by weight.
[6] (e) The aqueous polyurethane resin according to any one of [1] to [5], wherein the blocking agent is at least one selected from the group consisting of an oxime compound, a pyrazole compound, and a malonate compound. Dispersion.
[7] The aqueous polyurethane resin dispersion according to any one of [1] to [6], wherein (B) the chain extender comprises a polyamine compound having a total of 3 or more amino groups and / or imino groups in one molecule body.
[8] (B) The chain extender is a combination of a diamine compound, a polyamine compound having two amino groups and one or more imino groups, and the molar ratio thereof is 1/4 to 4/1. The aqueous polyurethane resin dispersion according to any one of 1] to [7].
[9] A coating material composition comprising the aqueous polyurethane resin dispersion according to any one of [1] to [8].
[10] A polyurethane resin film produced by heating and drying a composition containing any one of the aqueous polyurethane resin dispersions of [1] to [8].

  According to the present invention, even when a water-insoluble organic solvent is added, there is no significant increase in viscosity, and when a film is formed on a substrate, it is possible to achieve a large breaking energy in tension and excellent adhesion to the substrate. An aqueous polyurethane resin dispersion can be provided. Furthermore, the present invention can provide an aqueous polyurethane resin dispersion that provides a coating film having a low water swelling ratio and a high swelling ratio in an aqueous cleaning solution.

  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.

[Aqueous polyurethane resin dispersion]
The aqueous polyurethane resin dispersion comprises (a) a polyisocyanate compound, (b) a polyol compound, (c) an acidic group-containing polyol compound, (d) a hydroxyalkanoic acid, and (e) an isocyanato group that dissociates at 80 to 180 ° C. A polyurethane resin obtained by reacting (A) a polyurethane prepolymer obtained by reacting a blocking agent with (B) a chain extender having reactivity with an isocyanato group of the polyurethane prepolymer is obtained in an aqueous medium. An aqueous polyurethane resin dispersion dispersed in
The (b) polyol compound includes a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500,
The polyurethane resin has a total content of urethane bonds and urea bonds of 6 to 20% by weight based on solid content, and a content of carbonate bonds of 10 to 40% by weight based on solid content, The content ratio of the isocyanate group to which the blocking agent is bonded is 0.2 to 2.0% by weight in terms of solid content and isocyanato group, and the weight average molecular weight is 20,000 to 150,000.

  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, the tensile energy at break is high, the swelling rate into an aqueous cleaning liquid (for example, an aqueous solution containing alcohol, amine, aminoalcohol, cellosolve, etc.) is high, and it can be repainted. An aqueous polyurethane resin dispersion in which the viscosity does not increase remarkably by mixing the solvent can be obtained. 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 providing a multiple layer coating film, an aqueous coating material may be further apply | coated on an aqueous coating film. However, when the aqueous coating material is applied on the aqueous coating material, 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 forms a coating film having high breaking energy in tension, low swelling rate in water, and high water resistance. Moreover, since the coating film obtained using the water-based polyurethane resin dispersion of this invention has high adhesiveness to an electrodeposition coating film, it can be utilized as a protective film of a steel plate. Furthermore, the polyurethane resin film of the present invention can also be used as a decorative film.

[(A) polyisocyanate compound]
(A) The polyisocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups, and is an aromatic polyisocyanate compound, a linear or branched aliphatic polyisocyanate compound, and an alicyclic polyisocyanate compound. Any of these may be used.

  Aromatic polyisocyanate compounds include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, metaxylylene diisocyanate (XDI), 4, 4'-diphenylenemethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'- Examples include dimethyl-4,4′-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, and p-isocyanatophenylsulfonyl isocyanate.

  Linear or branched aliphatic polyisocyanate compounds are ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethyl. Hexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanate And natohexanoate.

  The alicyclic polyisocyanate compound is not particularly limited as long as it is a compound having an alicyclic structure. Isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene. Diisocyanate (hydrogenated TDI), 1,3-isocyanatomethylcyclohexane (hydrogenated XDI), bis (2-isocyanatoethyl) -4-dichlorohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2, , 6-norbornane diisocyanate and the like.

  (A) A polyisocyanate compound may be used individually by 1 type, and may use multiple types together.

  (A) The polyisocyanate compound is preferably an alicyclic polyisocyanate compound, more preferably an alicyclic diisocyanate compound, and particularly preferably 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI) and isophorone diisocyanate (IPDI). (A) When the polyisocyanate compound is an alicyclic polyisocyanate compound, preferably an alicyclic diisocyanate compound, it is possible to obtain a coating film that is less susceptible to yellowing, and the resulting coating film tends to have higher hardness. There is. When the polyisocyanate compound (a) is 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and / or isophorone diisocyanate (IPDI), the reactivity can be controlled, and the elastic modulus of the resulting coating film Is high and the water swelling rate is low.

[(B) Polyol compound]
(B) The polyol compound is (b-1) one or more kinds of acidic compounds including a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500. It is a polyol compound containing no group. That is, (b) the polyol compound is a polyol other than a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and containing no acidic group. (Hereinafter, also referred to as “(b-2) other polyol compound”).

[(B-1) Polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500]
A polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 (hereinafter also referred to as “component (b-1)”) has a number average molecular weight. Is a polycarbonate polyol having no acid group and 800 to 3,500, or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 and no acid group.

  When the number average molecular weight of the polycarbonate polyol or the polyester polycarbonate polyol is less than 800, there are problems such as low breaking energy in tension of the obtained coating film. When the number average molecular weight of the polycarbonate polyol or polyester polycarbonate polyol is more than 3,500, there is a problem that the resulting aqueous polyurethane resin dispersion is inferior in film-forming properties. The number average molecular weight of the component (b-1) is more preferably 1,500 to 3,200, and even more preferably 2,000 to 3,000, from the viewpoints of breaking energy and film forming property in the tension of the coating film. When two or more kinds of polycarbonate polyols and / or polyester polycarbonate polyols having different molecular weights are used in combination, the average molecular weight when the polycarbonate polyol and / or polyester polycarbonate polyol used in combination is mixed is preferably within this range.

  (B) The proportion of the component (b-1) in the total weight of the polyol compound is preferably 50 to 100% by weight, and 70 to 100% by weight from the viewpoint of breaking energy in the tension of the formed coating film. It is more preferable that it is 85-100 weight%.

In this specification, the number average molecular weight (Mn) of polycarbonate polyol or polyester polycarbonate polyol is determined from the hydroxyl value according to the following formula.
Mn = (56,100 × valence) / hydroxyl value In the formula, the valence is the number of hydroxyl groups in one molecule, and the hydroxyl value is a value measured in accordance with the method B of JIS K1557. When the polycarbonate polyol is a polycarbonate diol, or when the polyester polycarbonate polyol is a polyester polycarbonate diol, the valence is 2.

  The polycarbonate polyol as the component (b-1) can be produced by a general production method such as a transesterification method or a phosgene method of a polyol and a carbonate ester. The polyester polycarbonate polyol as component (b-1) is, for example, a method of transesterifying a cyclic ester compound and / or a hydroxycarboxylic acid ester and a polycarbonate polyol, or a method of transesterifying a polyester polyol and a carbonate ester. The polyester polyol and the polycarbonate polyol can be produced by a transesterification reaction.

  Hereinafter, the polyol, carbonic acid ester, cyclic ester compound, hydroxycarboxylic acid ester, and polyester polyol, which are raw materials for the component (b-1), will be described.

  Examples of the polyol include a linear aliphatic diol, a branched aliphatic diol, an alicyclic diol, an aromatic diol, and a polyfunctional polyol. Linear aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-pentanediol, 1,8 -Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol and the like. The branched aliphatic diols include 1,3-butanediol, 3-methylpentane-1,5-diol, 2-ethylhexane-1,6-diol, 2-methyl-1,3-pentanediol, neo Examples include pentyl glycol and 2-methyl-1,8-octanediol. The alicyclic diol is a diol having an alicyclic structure, and is 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,2′-bis (4-hydroxycyclohexyl) propane, 1,3-cyclohexanedimethanol. 1,4-cyclohexanedimethanol and the like. Examples of the aromatic diol include 1,4-benzenedimethanol. Examples of the polyfunctional polyol include trimethylolpropane and pentaerythritol.

  Only one kind of polyol can be used as the polycarbonate polyol or the polyester polycarbonate polyol, or two or more kinds can be used in combination as the polycarbonate polyol or the polyester polycarbonate polyol.

  Examples of the carbonate ester 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; alkylaryl carbonates such as methyl phenyl carbonate and ethyl phenyl carbonate; It is done. These may be used individually by 1 type and may use multiple types together.

  Examples of the cyclic ester compound include aliphatic lactones such as α-acetolactone, β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone. Hydroxycarboxylic acid esters include methyl glycolate, ethyl glycolate, methyl lactate, ethyl lactate, methyl tartronate, ethyl tartronate, methyl glycerate, ethyl glycerate, methyl 2-hydroxybutyrate, ethyl 2-hydroxybutyrate, 3- Examples include methyl hydroxybutyrate, ethyl 3-hydroxybutyrate, methyl malate, ethyl malate, methyl tartrate, ethyl tartrate, methyl 6-hydroxycaproate, and ethyl 6-hydroxycaproate. The cyclic ester compound and / or hydroxycarboxylic acid ester is preferably a cyclic ester compound, more preferably an aliphatic lactone having 2 to 10 carbon atoms, and an aliphatic having 4 to 6 carbon atoms in view of the breaking energy of the resulting coating film. Lactone is more preferred, and ε-caprolactone is particularly preferred.

  Examples of the polyester polyol include a polyester polyol obtained by a transesterification reaction between a polyol and a polycarboxylic acid ester, and a polyester polyol obtained by condensation polymerization of a polycarboxylic acid or a derivative thereof and the polyol. Examples of polycarboxylic acids or derivatives thereof include oxalic acid, succinic acid, malonic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid and other saturated aliphatic polycarboxylic acids; maleic acid, fumaric acid, itaconic acid Unsaturated aliphatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid And aromatic polycarboxylic acids such as acid anhydrides and acid halogenoids thereof. These may be used individually by 1 type and may use multiple types together.

  The polyester polyol can also be obtained by a transesterification reaction between a cyclic ester and / or a hydroxycarboxylic acid and a polyol.

The component (b-1) is obtained by using one or more selected from the group consisting of a linear aliphatic diol, a branched aliphatic diol, an alicyclic diol, an aromatic diol, and a polyfunctional polyol. It is more preferable to use a linear aliphatic diol and / or a branched aliphatic diol, and it is even more preferable to use a linear aliphatic diol. In addition, the linear aliphatic diol and the branched aliphatic diol preferably have 2 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, and 3 to 8 carbon atoms. More preferably. Diols such as alicyclic diols and aromatic diols preferably have 2 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, and still more preferably 3 to 8 carbon atoms. .
(B-1) A commercial item can be used for a component.

[(B-2) Other polyol compounds]
(B-2) The other polyol compound is not particularly limited as long as it is a polyol compound other than the component (b-1) and does not contain an acidic group. (B-2) Other polyol compounds include, for example, polyester polyol, polyether polyol, polycarbonate polyol having a number average molecular weight other than 800 to 3,500, polyester polycarbonate polyol having a number average molecular weight other than 800 to 3,500, and fat. Aromatic diol, alicyclic diol, aromatic diol, polyfunctional polyol and the like. (B-2) The other polyol compound is preferably an aliphatic diol, an alicyclic diol, a polycarbonate polyol having a number average molecular weight other than 800 to 3,500, and a polyester polycarbonate polyol having a number average molecular weight other than 800 to 3,500. . (B-2) Other polyol compounds do not include the (c) acidic group-containing polyol compound described later.

[(C) Acid group-containing polyol compound]
(C) The acidic group-containing polyol compound 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, Examples include 4-dihydroxybutanesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid, and the like. (C) One type of acidic group-containing polyol compound may be used alone, or a plurality of types may be used in combination. (C) The acidic group-containing polyol compound is preferably a dimethylol alkanoic acid having 4 to 12 carbon atoms containing two methylol groups from the viewpoint of availability and reactivity, and 2,2-dimethylolpropionic acid and More preferred is 2,2-dimethylolbutanoic acid.

[(D) Hydroxyalkanoic acid]
(D) Hydroxyalkanoic acid is not particularly limited as long as it is a compound having one carboxyl group and one hydroxyl group. (D) The number of carbon atoms of the hydroxyalkanoic acid is preferably 2-30, more preferably 6-30, and particularly preferably 10-26. (D) When the hydroxyalkanoic acid has 2 to 30 carbon atoms, the storage stability of the aqueous polyurethane resin dispersion is high, the water swelling rate of the resulting polyurethane film tends to be low, and the water resistance tends to be high. (D) Hydroxyalkanoic acid is glycolic acid (2-hydroxyacetic acid), hydroxypivalic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 10-hydroxydecanoic acid, hydroxypivalic acid (2,2-dimethyl-3 -Hydroxypropionic acid), 12-hydroxydodecanoic acid, 16-hydroxyhexadecanoic acid, lactic acid, trichlorolactic acid, salicylic acid, hydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxypropionic acid, 2-hydroxyoctanoic acid, Examples include 3-hydroxyundecanoic acid, 12-hydroxystearic acid, and 12-hydroxyoleic acid, and glycolic acid, 4-hydroxybutyric acid, hydroxypivalic acid, and 12-hydroxystearic acid are preferable. 12-hydroxystearic acid is particularly preferable as the (d) hydroxyalkanoic acid from the viewpoint that the water swelling rate of the resulting polyurethane film becomes lower. (D) Hydroxyalkanoic acid may be used individually by 1 type, and may use multiple types together.

[(E) Blocking agent for isocyanato group dissociating at 80 to 180 ° C.]
(E) The blocking agent for the isocyanato group that dissociates at 80 to 180 ° C. is not particularly limited as long as it is a compound that dissociates from the isocyanato group at 80 to 180 ° C. Here, the “isocyanato group blocking agent” is a compound capable of reacting with an isocyanato group to convert the isocyanato group into another group, and capable of reversibly converting from another group to the isocyanato group by heat treatment. Means.
(E) A blocking agent for an isocyanato group that dissociates at 80 to 180 ° C. is a malonic acid ester compound, preferably a malonic acid diester compound such as dimethyl malonate or diethyl malonate; 1,2-pyrazole, 3,5 -Pyrazole compounds such as dimethylpyrazole; oxime compounds such as 1,2,4-triazole and methylethylketoxime; diisopropylamine, caprolactam and the like. (E) The isocyanato group blocking agent that dissociates at 80 to 180 ° C. is preferably at least one selected from the group consisting of oxime compounds, pyrazole compounds, and malonic ester compounds from the viewpoint of dissociation temperature. (E) The isocyanato group blocking agent that dissociates at 80 to 180 ° C. is more preferably a pyrazole compound, and particularly preferably 3,5-dimethylpyrazole, from the viewpoint of high storage stability and low-temperature thermal crosslinkability. (E) The blocking agent for the isocyanato group that dissociates at 80 to 180 ° C. may be used alone or in combination of two or more.

[(A) Polyurethane prepolymer]
(A) The polyurethane prepolymer includes (a) a polyisocyanate compound, (b) a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500. One or more polyol compounds (hereinafter also simply referred to as “polyol compounds”), (c) acidic group-containing polyol compounds, (d) hydroxyalkanoic acids, and (e) blocking agents for isocyanato groups that dissociate at 80 to 180 ° C. Hereinafter, it is a polyurethane prepolymer obtained by simply reacting with a “blocking agent”. The production method of the polyurethane prepolymer is not particularly limited, and examples thereof include the following methods.

The first method performs a urethanization reaction by reacting (a) a polyisocyanate compound, (b) a polyol compound, and (c) an acidic group-containing polyol compound in the presence or absence of a urethanization catalyst. Then, (d) the hydroxyalkanoic acid is reacted, and finally (e) the blocking agent is reacted in the presence or absence of the blocking catalyst to perform the blocking reaction, and a part of the terminal isocyanate group is blocked. (A) A method for synthesizing a polyurethane prepolymer.
In the second method, a blocking reaction is performed by reacting (a) a polyisocyanate compound and (e) a blocking agent in the presence or absence of a blocking catalyst to block a part of the isocyanato group. The polyisocyanate compound was synthesized and reacted with (b) a polyol compound and (c) an acidic group-containing polyol compound in the presence or absence of a urethanization catalyst. d) A method of synthesizing (A) a polyurethane prepolymer by reacting with a hydroxyalkanoic acid.

  Urethane catalyst is not particularly limited, and salts of metals and organic and inorganic acids such as tin-based catalysts (trimethyltin laurate, dibutyltin dilaurate, etc.), lead-based catalysts (lead octylate, etc.), organometallic derivatives, amines Examples thereof include system catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, etc.), diazabicycloundecene catalysts, and the like. The urethanization catalyst is preferably dibutyltin dilaurate 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 urethanization 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) A chain extension agent will not be restrict | limited especially if it is a compound which has the reactivity with the isocyanato group of a polyurethane prepolymer. (B) The chain extender is, for example, hydrazine, ethylenediamine, 1,4-tetramethylenediamine, 2-methyl-1,5-pentanediamine, 1,6-hexamethylenediamine, 1,4-hexamethylenediamine, 3 -Diamine compounds such as aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3-bis (aminomethyl) cyclohexane, xylylenediamine, piperazine, 2,5-dimethylpiperazine, adipodihydrazide; diethylenetriamine, bis ( Triamine compounds such as 2-aminopropyl) amine and bis (3-aminopropyl) amine; triethylenetetramine, tripropylenetetramine, N- (benzyl) triethylenetetramine, N, N ′ ″-(dibenzyl) triethylenetetramine , N- (benzyl) -N ′ ″- 2-ethylhexyl) tetramine compounds such as triethylenetetramine; pentamine compounds such as tetraethylenepentamine and tetrapropylenepentamine; hexamine compounds such as pentaethylenehexamine and pentapropylenehexamine; polyamine compounds such as polyethyleneimine and polypropyleneimine; Polyol compounds such as 4-butanediol and 1,6-hexanediol; water and the like. (B) A chain extension agent may be used individually by 1 type, and may use multiple types together.

  (B) The chain extender preferably contains a polyamine compound having a total of three or more amino groups and / or imino groups in one molecule. When the (B) chain extender contains a polyamine compound having a total of three or more amino groups and / or imino groups in one molecule, the resulting coating film has a higher breaking energy and a higher water swelling ratio. Tend to be lower. (B) The chain extender is more preferably a combination of a polyamine compound having a total of three or more amino groups and / or imino groups in one molecule and a diamine compound. (B) The ratio of the polyamine compound having three or more amino groups and / or imino groups in total in one molecule in the chain extender is preferably 10 to 100 mol%, and more preferably 30 to 100 mol%. Is more preferable, and it is especially preferable that it is 30-80 mol%.

  From the viewpoint of reactivity with the polyurethane prepolymer, a polyamine compound having a total of three or more amino groups and / or imino groups in one molecule is diethylenetriamine, triethylenetetramine, bis (2-aminopropyl) amine, bis ( 3-aminopropyl) amine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, pentapropylenehexamine, etc., polyamine compounds having two amino groups and one or more imino groups in one molecule Or a mixture thereof is preferable, a triamine compound such as diethylenetriamine, bis (2-aminopropyl) amine, or bis (3-aminopropyl) amine is more preferable, and diethylenetriamine is more preferable.

  (B) The chain extender is more preferably a combination of a diamine compound and a polyamine compound having two amino groups and one or more imino groups in one molecule. (B) When the chain extender is a combination of a diamine compound and a polyamine compound having two amino groups and one or more imino groups in one molecule, the water swelling rate of the resulting polyurethane resin is kept low, The swelling rate of the aqueous cleaning liquid can be increased. In this case, the molar ratio of the diamine compound to the polyamine compound having two amino groups and one or more imino groups (diamine compound / polyamine compound having two amino groups and one or more imino groups) is 1/4. Is preferably 4/1, more preferably 1/3 to 3/1, and particularly preferably 1/2 to 2/1. When the molar ratio of the diamine compound to the polyamine compound having two amino groups and one or more imino groups is 1/4 to 4/1, the breaking energy of the resulting coating film tends to be higher.

  (B) When the chain extender is a combination of a diamine compound and a polyamine compound having two amino groups and one or more imino groups in one molecule, the weight average molecular weight of the polyurethane resin is 20,000 to 150, 000, the content of blocked isocyanate groups in the polyurethane resin is 0.2 to 2.0% by weight, and the acid value at the end of the polyurethane resin is easily adjusted to 3 to 30 mgKOH / g. In this case, the molar ratio with the diamine compound (diamine compound / polyamine compound having two amino groups and one or more imino groups) is preferably 1/4 to 4/1, and 1/3 to 3 / 1 is more preferable, and 1/2 to 2/1 is particularly preferable.

  The amount of the (B) chain extender is preferably equal to or less than the equivalent of the unblocked isocyanato group that becomes the chain extension origin in the (A) polyurethane prepolymer, and more preferably the amount of the unblocked isocyanato group. 0.7 to 0.99 equivalents. (B) When the amount of the chain extender is equal to or less than the equivalent of the unblocked isocyanato group, preferably 0.99 equivalent or less, the molecular weight of the chain-extended polyurethane resin tends to be suppressed. The strength of the coating film obtained by applying the obtained aqueous polyurethane resin dispersion tends to be further improved.

[Method for producing aqueous polyurethane resin dispersion]
The manufacturing method in particular of an aqueous polyurethane resin dispersion is not restrict | limited, The following method is mentioned. An unrestricted method for producing an aqueous polyurethane resin dispersion comprises reacting (a) a polyisocyanate compound, (b) a polyol compound, (c) an acidic group-containing polyol compound, (d) a hydroxyalkanoic acid, and (e) a blocking agent. To obtain a polyurethane prepolymer, to neutralize acidic groups in the polyurethane prepolymer, to disperse the polyurethane prepolymer in an aqueous medium, and to react the polyurethane prepolymer with the (B) chain extender to form an aqueous polyurethane. A step of obtaining a resin dispersion.

  In the method for producing an aqueous polyurethane resin dispersion, the step of obtaining a polyurethane prepolymer is as described above in the method for producing a polyurethane prepolymer. In the method for producing an aqueous polyurethane resin dispersion, the step of neutralizing acidic groups and the step of dispersing the polyurethane prepolymer in an aqueous medium may be performed separately or together. In the method for producing an aqueous polyurethane resin dispersion, the step of reacting the polyurethane prepolymer with the (B) chain extender may be after the step of dispersing the polyurethane prepolymer in the aqueous medium, and the polyurethane prepolymer in the aqueous medium. You may carry out with the process to disperse | distribute. Each step in the method for producing an aqueous polyurethane resin dispersion may be performed in an inert gas atmosphere or in the air.

  In the aqueous polyurethane resin dispersion, the total content of urethane bonds and urea bonds in the aqueous polyurethane resin dispersion is 6 to 20% by weight and 7 to 15% by weight based on the solid content. Is preferably 7.5 to 13.5% by weight, more preferably 8 to 13% by weight. Here, the content ratio of the urethane bond means the content ratio of the urethane bond unit (-NHCOO-) in the solid content of the polyurethane resin, and the content ratio of the urea bond means the urea bond unit (in the solid content of the polyurethane resin ( -NHCONH-) means the content ratio. If the total content of urethane bonds and urea bonds is less than 6% by weight, the coating film cannot be sufficiently formed, and the coating film surface becomes sticky after drying. In addition, when the total content of urethane bonds and urea bonds exceeds 20% 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 may be reduced. Since it is inferior, removal becomes difficult and repainting may not be possible.

  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 6 to 20% by weight based on the solid content. The content of urethane bonds in the aqueous polyurethane resin dispersion is preferably 4 to 15% by weight, more preferably 5 to 12% by weight, and 6 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 6 to 20% by weight based on the solid content. The urea bond content in the aqueous polyurethane resin dispersion is preferably 1 to 6% by weight, more preferably 1.5 to 5% by weight, and 2 to 4.5% by weight based on the solid content. It is particularly preferred that 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 ratio of the isocyanate group to which the blocking agent is bonded (also referred to as blocked isocyanate group) needs to be 0.2 to 2.0% by weight in terms of solid content and in terms of isocyanate group. More preferably 0.3 to 1.5% by weight, still more preferably 0.3 to 1.2% by weight, particularly preferably 0.4 to 1.2% by weight. . Here, the content ratio of the isocyanate group to which the blocking agent is bonded is calculated by calculating the content ratio of the isocyanate group to which the blocking agent is bonded in the solid content of the polyurethane resin as the content ratio of the isocyanate group (-NCO). means. The content ratio of the isosinato group to which the blocking agent is bonded in the aqueous polyurethane resin dispersion can be calculated from the amount of each component charged when preparing the aqueous polyurethane resin dispersion. When the content ratio of the isocyanate group to which the blocking agent is bonded is less than 0.2% by weight, there is a problem that the adhesion of the obtained coating film to the surface of the electrodeposition coated plate is poor. Moreover, when the content ratio of the isocyanate group to which the blocking agent is bonded exceeds 2.0% by weight, there is a problem that the elongation at break of the obtained coating film is small and only a coating film that is vulnerable to impact can be obtained.

  In the aqueous polyurethane resin dispersion, the content of carbonate bonds in the aqueous polyurethane resin dispersion is 10 to 40% by weight, more preferably 15 to 40% by weight, more preferably 18 to 35% by weight based on the solid content. % Is more preferable, and 20 to 30% by weight is particularly preferable. Here, the content ratio of the carbonate bond means the content ratio of the carbonate bond unit (—OCOO—) 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. Moreover, it can calculate from the infrared absorption spectrum of a coating film. When the content of carbonate bonds is less than 10% by weight, there is a problem that the elongation at break of the resulting coating film is small and only a coating film that is vulnerable to impact can be obtained. On the other hand, if the carbonate bond content exceeds 40% by weight, the coating film cannot be formed sufficiently, and the coating film surface becomes sticky after drying.

  When a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500 is used as the component (b-1), or when a polyol compound having an ester bond such as a polyester polyol is used as the component (b-2) The resulting aqueous polyurethane resin dispersion will contain ester bonds. By introducing an ester bond, the elongation at break tends to increase, but when too much is introduced, the water swelling rate increases. When the aqueous polyurethane resin dispersion contains an ester bond, the content of the ester bond is preferably 3 to 16% by weight, more preferably 4 to 14% by weight, and particularly preferably 4 to 12% by weight based on the solid content.

  The weight average molecular weight of the polyurethane resin is 20,000 to 150,000, preferably 25,000 to 120,000, more preferably 30,000 to 110,000, and 35,000 to 100. Is particularly preferred. When the weight average molecular weight of the polyurethane resin is less than 20,000, the breaking energy of the obtained coating film becomes low, and a coating film resistant to impact cannot be obtained. When the weight average molecular weight of the polyurethane resin is more than 150,000, it is difficult to remove the resulting aqueous polyurethane resin dispersion when applied to a substrate due to poor redispersibility of the paint or coating film in an aqueous solvent. It becomes difficult to repaint. When the weight average molecular weight of the polyurethane resin is from 35,000 to 100,000, the swelling rate to the aqueous cleaning liquid tends to be high and tends to be more excellent in cleaning properties, and the swelling rate to water is low, so the water resistance tends to be excellent. There is. In this specification, the weight average molecular weight is measured by gel permeation chromatography (GPC), and is a conversion value obtained from a standard curve of standard polystyrene prepared in advance.

Although the acid value of a polyurethane resin is not specifically limited, It is preferable that it is 10-40 mgKOH / g, It is more preferable that it is 13-35 mgKOH / g, It is especially preferable that it is 14-30 mgKOH / g. There exists a tendency for the dispersibility in an aqueous medium to improve that the acid value of a polyurethane resin is the range of 10-40 mgKOH / g.
The acid value derived from the molecular terminal of the polyurethane resin is not particularly limited, but is preferably 3 to 30 mgKOH / g, more preferably 4 to 25 mgKOH / g, and 5 to 20 mgKOH / g. Particularly preferred. When the acid value derived from the molecular terminal of the polyurethane resin is in the range of 3 to 30 mgKOH / g, there is a tendency that the viscosity does not increase remarkably when the water-insoluble organic solvent is mixed.
Therefore, the acid value of the polyurethane resin is preferably 10 to 40 mgKOH / g, and the acid value derived from the molecular terminal of the polyurethane resin is preferably 3 to 30 mgKOH / g. In particular, when the acid value of the polyurethane resin is in the range of 14 to 30 mgKOH / g and the acid value derived from the molecular terminal of the polyurethane resin is in the range of 5 to 20 mgKOH / g, the breaking energy of the coating film is increased. be able to.
The acid value of the polyurethane resin is the sum of (c) the acid value derived from the acidic group-containing polyol and (d) the acid value derived from the hydroxyalkanoic acid. Moreover, the acid value derived from the molecular terminal of the polyurethane resin is the acid value derived from (d) hydroxyalkanoic acid.
The acid value of the polyurethane resin is a value measured according to the indicator titration method of JIS K1557. The acid value derived from the molecular terminal of the polyurethane resin is calculated by calculating the molar concentration (mol / g) of hydroxyalkanoic acid on the basis of the solid content from the charged amount of each component when preparing the aqueous polyurethane resin dispersion. It is the value converted into the weight fraction (mgKOH / g) of potassium hydroxide required for the sum.

In the molecular terminal portion of the polyurethane resin, the molar ratio between the carboxy group and the isocyanate group to which the blocking agent is bonded (hereinafter also referred to as “terminal carboxy group / blocked NCO group”) is 10/90 to 70/30. Is preferable, 20/80 to 60/40 is more preferable, 30/70 to 60/40 is further preferable, and 30/70 to 49/51 is particularly preferable. In the terminal carboxy group / blocked NCO group, by reducing the number of moles of the terminal carboxy group relative to the number of moles of the blocked NCO group, a coating film that does not break (provided high breaking energy) unless higher energy is applied. An aqueous polyurethane resin dispersion can be obtained.
On the other hand, in the terminal carboxy group / blocked NCO group, if the number of moles of the terminal carboxy group is larger than the number of moles of the blocked NCO group, the coating film can be made flexible (low elastic modulus), and the elongation at break of the coating film Can be high. In order to obtain a coating film that is flexible and has high elongation, the terminal carboxy group / blocked NCO group is preferably 51/49 to 75/25, more preferably 55/45 to 70/30.

  The content of the alicyclic structure in the aqueous polyurethane resin dispersion is not particularly limited, but is preferably 6 to 30% by weight, more preferably 7 to 25% by weight, and 7 to 22 based on the solid content. It is more preferable that it is weight%, and it is especially preferable that it is 8-20 weight%. When the content of the alicyclic structure in the aqueous polyurethane resin dispersion is 6% by weight or more, the tensile strength of the coating film is increased and the breaking energy is increased. In addition, when the content of the alicyclic structure in the aqueous polyurethane resin dispersion is 30% by weight or less, when the obtained aqueous polyurethane resin dispersion is applied to a substrate, the paint or coating film is reconstituted in an aqueous solvent. Since the dispersibility is high, removal is easy and repainting is easier. For example, when the alicyclic structure is a cyclohexane ring, the content ratio of the alicyclic structure based on the solid content is a portion obtained by removing two hydrogen atoms from cyclohexane (the cyclohexane residue) in the solid content in the aqueous polyurethane resin dispersion. It shows how many groups are present.

〔Neutralizer〕
The aqueous polyurethane resin dispersion preferably contains a neutralizing agent as an optional component. The neutralizing agent is used to neutralize at least some of the acidic groups of the polyurethane prepolymer and disperse the polyurethane prepolymer in the aqueous medium. Here, the aqueous polyurethane resin dispersion containing a neutralizing agent is preferably obtained by reacting a polyurethane prepolymer dispersed in an aqueous medium with a chain extender. Neutralizing agents are trimethylamine, triethylamine, tri-n-propylamine, tributylamine, triethanolamine, aminomethylpropanol, aminomethylpropanediol, aminoethylpropanediol, trihydroxymethylaminomethane, monoethanolamine, N, N -Organic amines such as dimethylethanolamine and triisopropanolamine; inorganic alkali salts such as potassium hydroxide and sodium hydroxide; ammonia and the like. A neutralizer may be used individually by 1 type and may use 2 or more types together.

  From the viewpoint of workability, the neutralizing agent is preferably an organic amine, and more preferably triethylamine. The amount of the neutralizing agent is, for example, 0.4 to 1.2 equivalents, and preferably 0.6 to 1.0 equivalents per equivalent of acidic group in the aqueous polyurethane resin dispersion.

[Optional ingredients]
The aqueous polyurethane resin dispersion may contain amino alcohol, monoalcohol and monoamine as further optional components. For example, a polyurethane prepolymer containing a hydroxyl group at the molecular end can be obtained by reacting the polyurethane prepolymer with amino alcohol in a state where the polyurethane prepolymer is dispersed in water. As a result, the chain can be extended by a reaction with the isocyanate group that is generated by deblocking when the coating film is dried by heating. Thus, when adjusting the degree of crosslinking and controlling the elastic modulus of the coating film, it is effective to use amino alcohol. Examples of amino alcohols include ethanolamine, butanolamine, hexanolamine and the like, and ethanolamine is preferred from the viewpoint of water dispersibility. The amount of amino alcohol is preferably less than 2% by weight, more preferably less than 1% by weight, based on the solid content of the aqueous polyurethane resin dispersion.

  For example, (A) a polyurethane prepolymer having a molecular terminal nonreactive can be obtained by reacting a polyurethane prepolymer with a monoalcohol or monoamine in a state where the polyurethane prepolymer is dispersed in water. Thereby, a crosslinking degree can be adjusted and it becomes possible to control the elasticity modulus of a coating film. Examples of the monoalcohol include ethanol, n-propanol, isopropanol, n-butanol, hexanol, octanol and the like, and n-butanol is preferable from the viewpoint of ease of production. Examples of the monoamine include ethylamine, n-propylamine, isopropylamine, n-butylamine, n-hexylamine and the like. The amount of monoalcohol and monoamine added is preferably less than 2% by weight, more preferably less than 1% by weight, based on the solid content of the aqueous polyurethane resin.

  From the viewpoint of reactivity, the monoalcohol is preferably used in the production of the (A) polyurethane prepolymer. The monoamine is preferably used after (A) the polyurethane prepolymer is dispersed in an aqueous medium, and is preferably used before (B) the chain extender is added. (A) In the case of adding a monoalcohol during the production of the polyurethane prepolymer, it is preferable to carry out the reaction in a state heated to 60 ° C. or higher from the viewpoint of improving the reaction rate. When adding the said monoamine, it is preferable to make it react in the state of 60 degrees C or less from the point which suppresses 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 the water include clean water, ion-exchanged water, distilled water, and ultrapure water. However, considering the availability of the polyurethane resin particles due to the influence of salt, ion-exchanged water is considered. Is preferred.

  The hydrophilic organic solvent is a lower monohydric alcohol such as methanol, ethanol or propanol; a polyhydric alcohol such as ethylene glycol or glycerin; N-methylmorpholine, dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone or N-ethylpyrrolidone. And aprotic hydrophilic organic solvents such as 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.

[Coating film obtained by applying aqueous polyurethane resin dispersion]
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. Since the secondary hydroxyl group produced by ring opening of the epoxy group remains in the cationic type and the carboxyl group is introduced in the anionic type, the blocking agent is used in the heat drying step of the aqueous polyurethane resin dispersion of the present invention. Is considered to cause a cross-linking reaction with a free isocyanato group formed by dissociation. Such electrodeposition coatings are used in industrial machinery such as heavy machinery and agricultural machinery, vehicles such as automobiles and bicycles, prefabricated steel frames, fire doors, building materials such as 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 the electrodeposition coating film is formed using an application device or the like and baked at a temperature of 80 to 250 ° C. A drying step can be provided before the baking step, or baking can be performed at a time after the aqueous polyurethane resin dispersion is applied and dried, and another coating material is applied and dried. 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 step and the drying step.

[Coating material composition]
The coating material composition includes an aqueous polyurethane resin dispersion and optionally an additive. When the coating material composition does not contain an additive, the coating material composition consists only of an aqueous polyurethane resin dispersion. Additives include plasticizers, antifoaming agents, leveling agents, fungicides, rust inhibitors, matting agents, flame retardants, tackifiers, thixotropic agents, lubricants, antistatic agents, thickeners, thickeners , 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 a composition containing an aqueous polyurethane resin dispersion. The composition comprising the aqueous polyurethane resin dispersion comprises an aqueous polyurethane resin dispersion and optionally an additive. When the composition containing the aqueous polyurethane resin dispersion does not contain an additive, the composition containing the aqueous polyurethane resin dispersion consists only of the aqueous polyurethane resin dispersion. The additive in the composition containing the aqueous polyurethane resin dispersion is as described above in the coating composition.

  The method for producing the polyurethane resin film is not particularly limited. For example, a step of applying a composition containing an aqueous polyurethane resin dispersion on a releasable substrate, and drying the composition containing the aqueous polyurethane resin dispersion. Examples thereof include a method including a step of forming a polyurethane resin film and a step of peeling the releasable substrate and the polyurethane resin film.

  The peelable substrate is not particularly limited, and examples thereof include a glass substrate; a plastic substrate such as polyethylene terephthalate or polytetrafluoroethylene; a metal substrate; The peelable substrate is obtained by treating the surface of each substrate with a release agent. The coating device for applying the composition containing the aqueous polyurethane resin dispersion 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) The content ratio (urethane bond content) based on solid content of urethane bonds and the content ratio (urea bond content) based on solid content of urea bonds are determined based on the proportions of the raw materials of the aqueous polyurethane resin dispersion, The molar concentration (mole / g) of the urea bond 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) For the ester bond solid content content (ester bond content), the molar concentration (mol / g) of the ester bond is calculated from the charge ratio of each raw material of the aqueous polyurethane resin dispersion, and converted to a weight fraction. I wrote what I did. 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) For the carbonate bond solid content basis content (carbonate bond content), the carbonate bond molar concentration (mol / g) is calculated from the charge ratio of each raw material of the aqueous polyurethane resin dispersion, and converted to the weight fraction. I wrote what I did. 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) For the acid value derived from the molecular end (terminal acid value), the molar concentration (mol / g) of hydroxyalkanoic acid is calculated based on the solid content based on the charge ratio of each raw material of the aqueous polyurethane resin dispersion. Is converted to the weight fraction of potassium hydroxide required for neutralization (mgKOH / g).
(8) The content ratio (alicyclic structure content) based on the solid content of the alicyclic structure represents the weight fraction of the alicyclic structure calculated from the charging ratio of each raw material of the aqueous polyurethane resin dispersion. 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.
(9) The weight average molecular weight of the polyurethane resin in the aqueous polyurethane resin dispersion was measured by gel permeation chromatography (GPC), and a conversion value obtained from a standard polystyrene calibration curve prepared in advance was described.
(10) The content ratio of the isocyanate group to which the blocking agent based on the solid content in the aqueous polyurethane resin dispersion is bonded (in terms of isocyanate group, blocked NCO content) is the weight of the isocyanate group charged in the charged molar amount of the blocking agent. The ratio divided by the solid content weight of the aqueous polyurethane resin dispersion was expressed. 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.

(11) Swelling ratio of coating film in water: 0.3 mL of aqueous polyurethane resin dispersion was applied to 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
(12) 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 3 minutes, 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
(13) The elastic modulus, tensile strength, and elongation at break of the polyurethane resin film were 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.
(14) The breaking energy was determined by integrating the stress from zero elongation to elongation at break of the elongation-stress curve.
(15) The adhesion with the electrodeposited surface was evaluated as follows. An aqueous polyurethane resin dispersion was applied to an automotive steel plate cationic electrodeposition coating plate (manufactured by Nippon Test Panel Co., Ltd.) with a thickness of 40 μm (bar coater # 20), dried by heating at 140 ° C. for 30 minutes, and the resulting coating film was used. A cross-cut peel test was conducted. The coating film was cut at an interval of 1 mm vertically and horizontally in an area of 10 mm × 10 mm, and after sticking an adhesive tape, the number of cells remaining on the surface of the electrodeposition layer when peeled off was visually evaluated. For example, the case where 60 out of 100 remained was described as 60/100.
(16) The viscosity increase rate when 2-ethylhexanol was added was evaluated as follows. To 100 g of the aqueous polyurethane resin dispersion, 3 g of 2-ethylhexanol was added and 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.

[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, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1,993; hydroxyl value 56.3 mgKOH / g; 1,6-hexane) 230 g of polycarbonate diol obtained by reacting diol and dimethyl carbonate), 10.6 g of 2,2-dimethylolpropionic acid (DMPA) and 115 g of N-ethylpyrrolidone (NEP) were charged under a nitrogen stream. 99.4 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.28 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was carried out over 2.5 hours. Thereafter, 11.8 g of 12-hydroxystearic acid was injected, and stirring was continued for 2.5 hours at the same temperature. Further, 6.83 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 1.81% by weight. 449 g was extracted from the mixture obtained by adding and mixing 12.3 g of triethylamine to the reaction mixture, and added to 640 g of water under strong stirring. Subsequently, 11.8 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 10.5 g of 35 wt% diethylenetriamine aqueous solution were 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 0.10 mm.

[Example 2]
[Production of aqueous polyurethane resin dispersion (2)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,029; hydroxyl value 55.3 mg KOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 235 g, 2,2-dimethylolpropionic acid (DMPA) 7.93 g and N-ethylpyrrolidone (NEP) 113 g were charged under a nitrogen stream. 95.8 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 2.5 hours. Thereafter, 17.9 g of 12-hydroxystearic acid was injected, and stirring was continued for 2.5 hours at the same temperature. Further, 7.07 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 of free NCO groups at the end of the urethanization reaction was 1.69% by weight. 452 g was extracted from the mixture obtained by adding and mixing 11.9 g of triethylamine to the reaction mixture, and added to 650 g of water under strong stirring. Next, 11.2 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 9.91 g of 35 wt% diethylenetriamine aqueous solution were added to carry out 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 0.10 mm.

[Example 3]
[Production of aqueous polyurethane resin dispersion (3)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,029; hydroxyl value 55.3 mg KOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 240 g, 2,2-dimethylolpropionic acid (DMPA) 5.33 g and N-ethylpyrrolidone (NEP) 110 g were charged under a nitrogen stream. 93.2 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 2.5 hours. Thereafter, 24.5 g of 12-hydroxystearic acid was injected, and stirring was continued for 2 hours at the same temperature. Further, 7.08 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 1.39% by weight. 457 g was extracted from the mixture obtained by adding and mixing 12.3 g of triethylamine to the reaction mixture, and added to 670 g of water under strong stirring. Subsequently, 9.35 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 8.30 g of 35 wt% diethylenetriamine aqueous solution were 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 0.10 mm.

[Example 4]
[Production of aqueous polyurethane resin dispersion (4)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,007; hydroxyl value 55.9 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 305 g, 2,2-dimethylolpropionic acid (DMPA) 14.1 g and N-ethylpyrrolidone (NEP) 137 g were charged under a nitrogen stream. 108 g of isophorone diisocyanate (IPDI) and 0.35 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 2 hours. Thereafter, 15.4 g of 12-hydroxystearic acid was injected, and stirring was continued for 4 hours at the same temperature. Further, 8.47 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 2 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 1.98% by weight. 577 g was extracted from the mixture obtained by adding and mixing 16.4 g of triethylamine to the reaction mixture, and added to 840 g of water under vigorous stirring. Subsequently, 15.5 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 13.8 g of 35 wt% diethylenetriamine 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 0.10 mm.

[Example 5]
[Production of aqueous polyurethane resin dispersion (5)]
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 2,040; hydroxyl value 55.0 mgKOH / g; 1,6-hexanediol, ε-caprolactone) And 239 g of a polyester polycarbonate diol obtained by reacting dimethyl carbonate), 10.8 g of 2,2-dimethylolpropionic acid (DMPA) and 108 g of N-ethylpyrrolidone (NEP) were charged in a nitrogen stream. 96.5 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 2.5 hours. Thereafter, 12.6 g of 12-hydroxystearic acid was injected, and stirring was continued for 2.5 hours at the same temperature. Further, 7.03 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued at the same temperature for 2 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 1.86% by weight. 462 g was extracted from the mixture obtained by adding and mixing 12.8 g of triethylamine to the reaction mixture, and added to 680 g of water under strong stirring. Subsequently, 12.7 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 11.2 g of 35 wt% diethylenetriamine aqueous solution were 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 0.10 mm.

[Example 6]
[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 2,007; hydroxyl value 55.9 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) obtained in this manner, 2,2-dimethylolpropionic acid (DMPA) 12.5 g, and N-ethylpyrrolidone (NEP) 129 g were charged under a nitrogen stream. 115 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 2.5 hours. Thereafter, 3.58 g of glycolic acid was injected, and stirring was continued for 2 hours at the same temperature. Further, 8.41 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 2 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 1.86% by weight. From the mixture obtained by adding and mixing 14.9 g of triethylamine to the reaction mixture, 532 g was extracted and added to 770 g of water under strong stirring. Subsequently, 14.5 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 12.8 g of 35 wt% diethylenetriamine aqueous solution were 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 0.10 mm.

[Example 7]
[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 2,014; hydroxyl value 55.7 mgKOH / g; 1,6-hexanediol, ε-caprolactone) And 251 g of a polyester polycarbonate diol obtained by reacting dimethyl carbonate), 17.4 g of 2,2-dimethylolpropionic acid (DMPA) and 129 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream. 113 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 4.5 hours. Thereafter, 7.76 g of hydroxypivalic acid was injected, and stirring was continued for 4 hours at the same temperature. Further, 7.62 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 content of free NCO groups at the end of the urethanization reaction was 1.46% by weight. 509 g was extracted from the mixture obtained by adding and mixing 23.6 g of triethylamine to the reaction mixture, and added to 710 g of water under strong stirring. Subsequently, 27.7 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 (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 0.10 mm.

[Example 8]
[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 2,004; hydroxyl value 56.0 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 145 g, polytetramethylene ether glycol (PTMG) 70.5 g having a number average molecular weight of 2,000, 10.1 g 2,2-dimethylolpropionic acid (DMPA) and N-ethylpyrrolidone (NEP) ) 108 g was charged under a nitrogen stream. 90.5 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.27 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 4 hours. Thereafter, 10.9 g of 12-hydroxystearic acid was injected, and stirring was continued at the same temperature for 1.5 hours. Further, 6.47 g of 3,5-dimethylpyrazole (DMPZ) was injected, and stirring was continued for 2 hours at the same temperature to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 1.80% by weight. 426 g was extracted from the mixture obtained by adding and mixing 11.0 g of triethylamine to the reaction mixture, and added to 600 g of water under strong stirring. Subsequently, 11.1 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 9.90 g of 35 wt% diethylenetriamine aqueous solution were added to carry out 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 0.10 mm.

[Example 9]
[Production of aqueous polyurethane resin dispersion (9)]
In the same reaction vessel as in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,036; hydroxyl value 55.1 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) obtained in this manner, 2,2-dimethylolpropionic acid (DMPA) 17.7 g, and N-ethylpyrrolidone (NEP) 196 g were charged under a nitrogen stream. 166 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.46 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was carried out over 2.5 hours. Thereafter, 25.6 g of 12-hydroxystearic acid was injected, and stirring was continued for 2.5 hours at the same temperature. Further, 12.2 g of methyl ethyl ketone oxime (MEKO) 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 1.78% by weight. 785 g was extracted from the mixture obtained by adding and mixing 21.4 g of triethylamine to the reaction mixture, and added to 1100 g of water under strong stirring. Subsequently, 20.5 g of 35 wt% 2-methyl-1,5-pentanediamine aqueous solution and 18.2 g of 35 wt% diethylenetriamine aqueous solution were 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 0.10 mm.

[Example 10]
[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 2,029; hydroxyl value 55.3 mg KOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 252 g, 2,2-dimethylolpropionic acid (DMPA) 8.00 g and N-ethylpyrrolidone (NEP) 111 g were charged under a nitrogen stream. 89.3 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.29 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 2.5 hours. Thereafter, 34.0 g of 12-hydroxystearic acid was injected, and stirring was continued for 3 hours at the same temperature. Further, 8.18 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 0.698% by weight. 488 g was extracted from the mixture obtained by adding and mixing 18.0 g of triethylamine to the reaction mixture, and added to 710 g of water under strong stirring. Subsequently, 7.35 g of 35% by weight diethylenetriamine 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 0.10 mm.

[Example 11]
[Production of aqueous polyurethane resin dispersion (11)]
In the same reaction vessel as in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1,968; hydroxyl value 57.0 mg KOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 243 g, 2,2-dimethylolpropionic acid (DMPA) 8.23 g and Idemitsu Kosan Ecamide M-100 122 g were charged under a nitrogen stream. 95.2 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.27 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 2.5 hours. Thereafter, 41.7 g of 12-hydroxystearic acid was injected, and stirring was continued at the same temperature for 3.5 hours. Further, 7.27 g of methyl ethyl ketone oxime (MEKO) 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 0.691% by weight. 500 g was extracted from the mixture obtained by adding and mixing 20.4 g of triethylamine to the reaction mixture, and added to 710 g of water under strong stirring. Subsequently, 7.47 g of 35% by weight diethylenetriamine 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 0.10 mm.

[Comparative Example 1]
[Production of aqueous polyurethane resin dispersion (12)]
In a reaction vessel similar to that in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1,990; hydroxyl value 56.4 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were added. Polycarbonate diol (301 g obtained by reaction), 2,2-dimethylolpropionic acid (DMPA) (20.4 g) and N-methylpyrrolidone (NMP) (153 g) were charged in a nitrogen stream. Thereafter, the mixture was heated and stirred at 60 ° C., and it was confirmed that DMPA was dissolved. 139 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.36 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. and subjected to urethanization reaction for 5 hours to obtain a polyurethane prepolymer. . The content of free isocyanate groups at the end of the urethanization reaction was 2.75% by weight. The reaction mixture was cooled to 80 ° C., 584 g was extracted from the mixture obtained by adding and mixing 15.4 g of triethylamine, and added to 838 g of water under strong stirring. Then, 58.3 g of 35% by weight 2-methyl-1,5-diaminopentane 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 0.10 mm.

[Comparative Example 2]
[Production of aqueous polyurethane resin dispersion (13)]
In a reaction vessel similar to that in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,000; hydroxyl value 56.1 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were added. (Polycarbonate diol obtained by reaction) 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. Then, 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 (13).

[Production of polyurethane film (M)]
The aqueous polyurethane resin dispersion (13) 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 0.10 mm.

[Comparative Example 3]
[Production of aqueous polyurethane resin dispersion (14)]
In a reaction vessel similar to that in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 2,000; hydroxyl value 56.1 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were added. (Polycarbonate diol obtained by reaction) 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., and it was confirmed 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., and a urethanization reaction was carried out 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 aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (14).

[Production of polyurethane film (N)]
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 (N). The film thickness of the obtained polyurethane film (N) was 0.10 mm.

[Comparative Example 4]
[Production of aqueous polyurethane resin dispersion (15)]
In the same reaction vessel as in Example 1, ETERRNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1,988; hydroxyl value 56.4 mgKOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 488 g, 2,2-dimethylolpropionic acid (DMPA) 15.9 g and N-methylpyrrolidone (NMP) 282 g were charged under a nitrogen stream. 176 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.55 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C. to carry out a urethanization reaction over 3 hours. Thereafter, 66.7 g of 12-hydroxystearic acid was injected, and stirring was continued at the same temperature for 5 hours to obtain a polyurethane prepolymer. The free NCO group content at the end of the urethanization reaction was 1.34% by weight. 910 g was extracted from the mixture obtained by adding and mixing 35.5 g of triethylamine to the reaction mixture, and added to 1190 g of water under strong stirring. Subsequently, 27.5 g of 35% by weight diethylenetriamine aqueous solution was added to carry out chain extension reaction to obtain an aqueous polyurethane resin dispersion (15).

[Manufacture of polyurethane film (O)]
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 (O). The film thickness of the obtained polyurethane film (O) was 0.10 mm.

[Comparative Example 5]
[Production of aqueous polyurethane resin dispersion (16)]
In the same reaction vessel as in Example 1, ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries; number average molecular weight 1,965; hydroxyl value 57.1 mg KOH / g; 1,6-hexanediol and dimethyl carbonate were reacted. Polycarbonate diol) 268 g, 2,2-dimethylolpropionic acid (DMPA) 8.85 g and N-ethylpyrrolidone (NEP) 130 g were charged under a nitrogen stream. 96.6 g of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) and 0.29 g of dibutyltin dilaurate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was performed over 2.5 hours. Thereafter, 36.9 g of 12-hydroxystearic acid was injected, and stirring was continued for 3 hours at the same temperature. Further, 8.62 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 content of free NCO groups at the end of the urethanization reaction was 0.743% by weight. 539 g was extracted from the mixture obtained by adding and mixing 19.6 g of triethylamine to the reaction mixture, and added to 759 g of water under strong stirring. Then, 14.3 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 (16).

[Production of polyurethane film (P)]
The aqueous polyurethane resin dispersion (16) 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 (P). The film thickness of the obtained polyurethane film (P) was 0.10 mm.

  Urethane bond content ratio, urea bond content ratio, ester bond content ratio, carbonate bond content ratio, alicyclic structure content ratio, and blocked isocyanate group content in the aqueous polyurethane resin dispersions (1) to (16) Ratio (isocyanato group conversion), acid value, terminal acid value, molar ratio of carboxy group derived from hydroxycarboxylic acid and isocyanate group to which blocking agent is bonded at the molecular end of polyurethane resin (terminal carboxy group / blocking) NCO groups) and weight average molecular weight are listed in Table 1. The water swelling ratio of the coating film of the aqueous polyurethane resin dispersions (1) to (16), the swelling ratio to the cleaning liquid, the results of the adhesion test with the electrodeposited surface, and the thickening ratio when 2-ethylhexanol is added are shown. 2. Table 2 shows the tensile properties of the polyurethane films (A) to (P).

  Abbreviations in the table represent the following. H12-MDI is 4,4'-dicyclohexylmethane diisocyanate, IPDI is isophorone diisocyanate, UH-200 is Ube Industries 'ETERNACOLL UH-200, UHC50-200 is Ube Industries' ETERNACOLL UHC50-200, PTMG is a number Polytetramethylene ether glycol having an average molecular weight of 2,000, HS is 12-hydroxystearic acid, GA is glycolic acid, HP is hydroxypivalic acid, DMPZ is 3,5-dimethylpyrazole, MEKO is methyl ethyl ketoxime , MPMD represents 2-methyl-1,5-pentanediamine, and DETA represents diethylenetriamine.

  As described in the examples, the aqueous polyurethane resin dispersion of the present invention has a high swelling ratio of the coating film to the cleaning liquid, a low water swelling ratio, a high breaking energy, and a high adhesion to the electrodeposited surface. The viscosity increase rate when adding a hydrophobic solvent is low. As described in Comparative Example 1, when the hydroxyalkanoic acid and the isocyanato group blocking agent are not contained, the swelling ratio to the cleaning liquid is lowered. As described in Comparative Example 2, if no hydroxyalkanoic acid is contained, the viscosity increase rate when a hydrophobic solvent is added increases. As described in Comparative Example 3, when a polyamine having three or more amino groups or imino groups is contained in the molecule and no hydroxyalkanoic acid is contained, the breaking energy is lowered. As described in Comparative Example 4, if the blocking agent for the isocyanato group is not included, the adhesion with the electrodeposited surface is lowered. As described in Comparative Example 5, when the weight average molecular weight of the polyurethane resin is less than 20,000, the water swelling rate is high and the breaking energy is remarkably reduced.

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

Claims (10)

(A) a polyisocyanate compound, (b) a polyol compound, (c) an acidic group-containing polyol compound, (d) a hydroxyalkanoic acid, and (e) a blocking agent for an isocyanato group that dissociates at 80 to 180 ° C. An aqueous polyurethane in which a polyurethane resin obtained by reacting the obtained (A) polyurethane prepolymer with the (B) chain extender having reactivity with the isocyanate group of the polyurethane prepolymer is dispersed in an aqueous medium A resin dispersion,
The (b) polyol compound includes a polycarbonate polyol having a number average molecular weight of 800 to 3,500 and / or a polyester polycarbonate polyol having a number average molecular weight of 800 to 3,500,
The polyurethane resin has a total content of urethane bonds and urea bonds of 6 to 20% by weight based on solid content, and a content of carbonate bonds of 10 to 40% by weight based on solid content, An aqueous polyurethane resin dispersion in which the content of the isocyanate group to which the blocking agent is bonded is 0.2 to 2.0% by weight in terms of solid content and isocyanato group, and the weight average molecular weight is 20,000 to 150,000. body.   The aqueous polyurethane resin dispersion according to claim 1, wherein the acid value is 10 to 40 mgKOH / g, and the acid value derived from the molecular terminal is 3 to 30 mgKOH / 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 hydroxyalkanoic acid has 2 to 30 carbon atoms.   The water-based polyurethane resin dispersion as described in any one of Claims 1-4 whose alicyclic structure content rate is 6-30 weight% on the solid content basis.   (E) The aqueous polyurethane resin dispersion according to any one of claims 1 to 5, 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. body.   (B) The water-based polyurethane resin dispersion as described in any one of Claims 1-6 in which a chain extender contains the polyamine compound which has a total of 3 or more of an amino group and / or imino group in 1 molecule.   (B) The chain extender is a combination of a diamine compound, a polyamine compound having two amino groups and one or more imino groups, and the molar ratio thereof is 1/4 to 4/1. The aqueous polyurethane resin dispersion according to any one of 7.   A coating material composition comprising the aqueous polyurethane resin dispersion according to any one of claims 1 to 8.   The polyurethane resin film manufactured by heat-drying the composition containing the aqueous polyurethane resin dispersion as described in any one of Claims 1-8.