JP2007031482A - Urethane emulsion and aqueous polyurethane composition given by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous polyurethane composition capable of forming a film in a relatively short time and capable of giving a cured product excellent in water resistance, and to provide a urethane emulsion used for the same. <P>SOLUTION: This urethane emulsion is obtained by reacting a urethane prepolymer which has a carboxy group and a functional group having an acidity higher than that of the carboxy group with a tertiary amine and/or ammonia in water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a urethane emulsion and an aqueous polyurethane composition using the same.

In production lines using solvent-based adhesives, solvent-free technology for adhesives has been developed from the viewpoint of improving the work environment and taking measures against VOCs in products. As this solvent-free technology, it is known to use an aqueous polyurethane emulsion (aqueous polyurethane resin).
However, when an aqueous polyurethane emulsion is used, the initial adhesiveness (setting property) on the line is inferior, and the line speed at the same level as that of the solvent-based urethane adhesive cannot be maintained, that is, the drying property is inferior. There was a problem.

  In order to solve such a problem, Patent Document 1 describes that “a hydrophilic group-containing isocyanate-terminated prepolymer is dispersed in water containing a phosphate and, if necessary, a neutralizing agent, and then reacted with a chain extender. Or a hydrophilic group-containing isocyanate-terminated prepolymer is mixed with a phosphate, a chain extender, and optionally water containing a neutralizing agent, and the chain extension reaction and dispersion in an aqueous medium are simultaneously performed. A method for producing a polyurethane resin aqueous dispersion characterized by the above is proposed. In Patent Document 2, “(1) Hydrophobic organic solvent solution of hydrophilic group-containing isocyanate-terminated prepolymer is neutralized as necessary. Water containing an agent is mixed under mechanical shearing force and dispersed in an aqueous medium, and then reacted with a chain extender, or a hydrophobic organic solution of a hydrophilic group-containing isocyanate-terminated prepolymer. The solution is mixed with water containing a chain extender and, if necessary, a neutralizing agent under mechanical shearing force, and the chain extension reaction and dispersion in an aqueous medium are performed simultaneously, and then (2) degassing under reduced pressure. "A method for producing an aqueous dispersion of a high solid content polyurethane resin characterized by performing a solvent" has been proposed.

  Patent Document 3 states that “an emulsion (A) comprising a urethane resin having a polyester skeleton and a polyether skeleton in a polymer skeleton, and further having an acid group, and an ethylene content of 5 to 40% by weight. And, with respect to 100 parts by weight of the main agent formed by blending an emulsion (B) made of an ethylene-vinyl acetate copolymer with an undissolved substance (toluene insolubles) of toluene in the dry film being 70% by weight or more, "Adhesive composition characterized in that 2 to 20 parts by weight of a compound having two or more functional groups capable of reacting with an acid group is blended as a curing agent."

  However, the polyurethane resin aqueous dispersion obtained by the production methods described in Patent Documents 1 and 2 and the adhesive composition described in Patent Document 3 were used in an environment with a relatively short drying time such as a high-speed production line. In this case, the film is not sufficiently formed. For this reason, there is a problem that moisture remains in the adhesive to cause poor adhesion.

  In order to solve the above-mentioned problems, a method has been proposed in which a crosslinking agent such as oxazoline or carbodiimide is added to an aqueous polyurethane resin and reacted with a carboxy group of the aqueous polyurethane resin to introduce a crosslinked structure into the film. (Patent Document 4).

JP-A-5-306317 JP-A-5-320361 JP-A-10-140126 JP-A-6-212081

  However, even when the method described in Patent Document 4 is used, when used in an environment where the drying time is short, the crosslinking reaction does not proceed sufficiently and satisfactory water resistance cannot be obtained.

  An object of this invention is to provide the water-based polyurethane composition which can form a membrane | film | coat in a comparatively short time, and can obtain the hardened | cured material excellent in water resistance, and the urethane emulsion used therefor.

As a result of intensive studies, the present inventor has obtained a urethane obtained by reacting a urethane prepolymer having a carboxy group and a functional group having a higher acidity than the carboxy group with a tertiary amine and / or ammonia in water. An aqueous polyurethane composition containing an emulsion and a compound having two or more compounds selected from the group consisting of an oxazoline group, a carbodiimide group, and an aziridine group can form a film in a relatively short time, and is water resistant. As a result of finding out that an excellent cured product can be obtained, the present invention has been completed.
In the present specification, “water resistance” means that it is difficult to dissolve in water.

That is, the present invention provides the following (1) to (7).
(1) A urethane emulsion obtained by reacting a urethane prepolymer having a carboxy group and a functional group having a higher acidity than the carboxy group with a tertiary amine and / or ammonia in water.
(2) The urethane prepolymer includes a polyisocyanate compound (A) having two or more isocyanate groups, a polyol compound (B) having two or more hydroxy groups, a group having reactivity with an isocyanate group, and a carboxy group. The urethane emulsion according to (1) above, obtained by copolymerizing the compound (D) having a reactivity with the compound (C) having an isocyanate group and a functional group having a higher acidity than the carboxy group .
(3) The urethane emulsion according to (1) or (2), wherein the functional group having a higher acidity than the carboxy group is a sulfo group.
(4) The urethane emulsion according to any one of (1) to (3), wherein the tertiary amine is triethylamine.
(5) The urethane emulsion according to any one of (1) to (4) above,
An aqueous polyurethane composition comprising a crosslinking agent having at least one selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group.
(6) The aqueous polyurethane composition according to (5), wherein the crosslinking agent is an aqueous resin and / or emulsion having at least two selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group. object.
(7) The molar ratio of the carboxy group of the urethane prepolymer and the total of the oxazoline group, carbodiimide group and aziridine group of the crosslinking agent is 1.0 / 0.5 to 1.0 / 2.0. The water-based polyurethane composition according to the above (5) or (6).

  ADVANTAGE OF THE INVENTION According to this invention, the water-based polyurethane composition which can form a membrane | film | coat in a comparatively short time, and can obtain the hardened | cured material excellent in water resistance, and the urethane emulsion used for it can be provided. This is very useful because it can improve the work environment in the production line and take measures against VOCs in products.

Hereinafter, the present invention will be described in more detail.
The urethane emulsion of the present invention is a urethane emulsion obtained by reacting a urethane prepolymer having a carboxy group and a functional group having a higher acidity than the carboxy group with a tertiary amine and / or ammonia in water. .

  The urethane prepolymer used in the urethane emulsion of the present invention is not particularly limited as long as it is a urethane prepolymer having a carboxy group and a functional group having a higher acidity than the carboxy group. Specifically, for example, a polyisocyanate compound (A) having two or more isocyanate groups, a polyol compound (B) having two or more hydroxy groups, a compound having reactivity with an isocyanate group, and a compound having a carboxy group Preferable examples include urethane prepolymers produced by copolymerizing compound (D) having (C) and a group having reactivity with an isocyanate group and a functional group having a higher acidity than a carboxy group.

As said polyisocyanate compound (A), the various thing used for manufacture of a normal polyurethane resin can be used. Specifically, for example, TDI such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; MDI such as diphenylmethane-4,4′-diisocyanate; tetramethylxylylene diisocyanate (TMXDI), trimethylhexamethylene Diisocyanate (TMHMDI), 1,5-naphthalene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), triphenylmethane triisocyanate, norbornane skeleton And modified products such as diisocyanates (NBDI) having these and isocyanurate forms thereof.
These may be used alone or in combination of two or more.

  Among these isocyanate group-containing compounds, TDI and MDI are preferable. Since these polyisocyanates are general-purpose, they are inexpensive and easily available.

  The polyol compound (B) is an alcohol obtained by replacing a plurality of hydrocarbon hydrogens with a hydroxy group. Examples thereof include a product obtained by addition polymerization of at least one alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran to an active hydrogen-containing compound having two or more active hydrogens in the molecule.

Examples of the active hydrogen-containing compound include polyhydric alcohols, amines, alkanolamines, polyhydric phenols, and the like.
Specific examples of the polyhydric alcohols include ethylene glycol, propylene glycol, butanediol, diethylene glycol, glycerin, hexanetriol, trimethylolpropane, pentaerythritol and the like.
Specific examples of amines include ethylenediamine and hexamethylenediamine.
Specific examples of alkanolamines include ethanolamine and propanolamine.
Specific examples of polyhydric phenols include resorcin and bisphenols.

Specific examples of the polyol compound (B) include polyether polyols such as polytetramethylene glycol, polyethylene glycol, polypropylene glycol, polyoxypropylene glycol and polyoxybutylene glycol; polybutadiene polyol, polyisoprene polyol and the like. Polyolefin polyols; adipate polyols; lactone polyols; polyester polyols such as castor oil.
These may be used alone or in combination of two or more.

  The polyol compound (B) preferably has a number average molecular weight of about 500 to 10000, more preferably about 2000 to 6000.

The compound (C) is a compound having a group reactive with an isocyanate group and a carboxy group.
Specific examples of the group having reactivity with an isocyanate group include a hydroxy group, an amino group (—NH ₂ ), an imino group (—NH—), a mercapto group, and the like. In the present invention, the group having reactivity with the isocyanate group in the compound (C) does not contain a carboxy group.

Specific examples of such a compound (C) include aliphatic monohydroxycarboxylic acids such as hydroxyacetic acid, hydroxypropionic acid, and hydroxybutyric acid; hydroxybenzoic acid, hydroxyethylbenzoic acid, hydroxycinnamic acid, and the like. Aromatic monohydroxycarboxylic acid; dihydroxycarboxylic acid such as dimethylolpropionic acid and dimethylolacetic acid; mercaptocarboxylic acid such as mercaptoacetic acid, mercaptopropionic acid and mercaptobenzoic acid; aminocarboxylic acid such as aminoadipic acid and aminobenzoic acid, etc. Can be mentioned.
These may be used alone or in combination of two or more.
Among these, dihydroxycarboxylic acid is preferable because the reactivity with isocyanate is equivalent to that of the polyol compound (B) and the reaction can be easily controlled.

The compound (D) is a compound having a group having reactivity with an isocyanate group and a functional group having a higher acidity than the carboxy group.
The group having an isocyanate group and a reactive group is the same as that of the compound (C) described above.

The functional group having a higher acidity than the carboxy group (hereinafter referred to as “functional group (d)”) means a functional group having a higher acidity (lower pH) than the carboxy group of the urethane prepolymer. To do. This functional group (d) participates as a catalyst in the reaction between the carboxy group of the urethane prepolymer and the reactive group (for example, oxazoline group) of the crosslinking agent described later. Therefore, the time required for the composition of the present invention to form a film can be shortened.
The functional group (d) has a higher reactivity with a tertiary amine than a carboxy group. Therefore, it reacts preferentially with a tertiary amine described later and ionizes to stabilize the emulsion. Since the functional group (d) does not act as a catalyst in an ionized state, the composition of the present invention is excellent in storage stability even when it is a one-component type. And when drying the composition of this invention, a tertiary amine volatilizes, and a functional group (d) reproduces in connection with it, and can act as a catalyst as mentioned above.

Although this functional group is not particularly limited, specific examples thereof include a sulfo group (—SO ₃ H) and a phosphate group (—H ₂ PO ₄ ). In particular, a sulfo group is preferred from the viewpoint of excellent dispersion stability of urethane emulsion particles in water.

  Specific examples of such a compound (D) include hydroxysulfonic acid such as hydroxybenzenesulfonic acid; mercaptosulfonic acid such as 3N-mercaptoethanesulfonic acid; aminosulfonic acid such as aminobenzenesulfonic acid, and the like. Can be mentioned. These may be used alone or in combination of two or more.

Although the manufacturing method of the said urethane prepolymer is not specifically limited, For example, a polyisocyanate compound (A), a polyol compound (B), a compound (C), and a compound (D) are polymerized by stirring (at the same time) etc. simultaneously. A method is mentioned.
In the production of the urethane prepolymer, the order of adding the polyol compound (B), the compound (C), and the compound (D) is not particularly limited, and may be added all at the same time. May be. For example, according to an ordinary urethane prepolymer production method, a polyisocyanate compound (A) and a polyol compound (B) are reacted to produce a urethane prepolymer, and then added by adding the compound (C) and the compound (D). It is also possible to use a method of

The copolymerization is preferably performed so that the isocyanate group content (NCO%) of the resulting urethane prepolymer is 0.3 to 3%.
Moreover, 1-50 mass% of polyisocyanate compounds (A) and a polyol compound (B) with respect to the total mass of a polyisocyanate compound (A), a polyol compound (B), a compound (C), and a compound (D). 30 to 90% by mass, 0.1 to 20% by mass of the compound (C) and 1.0 to 5.0% by mass of the compound (D) are contained under an inert gas atmosphere at 60 to 90 ° C. It is preferable to stir for about 2 to 8 hours. Here, NCO% represents mass% of NCO groups with respect to the total mass of the urethane prepolymer.

Moreover, the said copolymerization can be performed in presence of urethanization catalysts, such as an organotin compound, an organic bismuth, and an amine as needed, and it is preferable to carry out in presence of an organotin compound.
Specific examples of the organic tin compound include stannous acetate such as stannous acetate, stannous octoate, stannous laurate, and stannous oleate; dibutyltin acetate, dibutyltin dilaurate, and dibutyltin. Dialkyltin salts of carboxylic acids such as maleate, dibutyltin di-2-ethylhexoate, dilauryltin diacetate, dioctyltin diacetate; hydroxylations such as trimethyltin hydroxide, tributyltin hydroxide, trioctyltin hydroxide Trialkyltin: Dialkyltin oxides such as dibutyltin oxide, dioctyltin oxide and dilauryltin oxide; dialkyltin chlorides such as dibutyltin dichloride and dioctyltin dichloride, and the like. These may be used alone or in combination of two or more.
Of these, dibutyltin dilaurate, dibutyltin acetate, and dibutyltin maleate are preferred because they are relatively inexpensive and easy to handle.

  The weight average molecular weight of the urethane prepolymer obtained by such copolymerization is preferably 1500 to 30000, and more preferably 3000 to 20000.

  The urethane prepolymer is emulsified by reacting with a tertiary amine and / or ammonia in water to form a stabilized urethane emulsion.

The tertiary amine is triethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo (5,4,0) undecene-7, etc. Is mentioned. These may be used alone or in combination of two or more.
Among the tertiary amines and ammonia, triethylamine and ammonia are preferable because they easily volatilize when the emulsion is dried.

  In general, sodium hydroxide, which is a strong base, is used as an emulsifier for a compound having a functional group (d) (for example, a sulfo group). However, when sodium hydroxide is used, since sodium hydroxide does not volatilize, the sulfo group is not regenerated and the above-described catalytic action cannot be exhibited. On the other hand, since the urethane emulsion of the present invention uses a tertiary amine and / or ammonia as an emulsifier, the tertiary amine and the like are volatilized at the time of drying and the sulfo group is regenerated, and the above-described catalytic action can be exhibited.

  The urethane prepolymer can be dispersed in water by adding a viscosity modifier and a chain extender, if necessary, in addition to the tertiary amine and the like.

  Examples of the viscosity modifier include organic solvents that are compatible with water, and specific examples thereof include ethyl acetate, acetone, and methyl ethyl ketone.

  Specific examples of the chain extender include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and triethylenetetramine; alicyclic diamines such as isophorone diamine and piperazine; aromatic diamines such as diphenyldiamine; A triamine etc. are mentioned.

  The method for producing the urethane emulsion of the present invention is not particularly limited. For example, the urethane prepolymer, the tertiary amine, and if necessary, the viscosity modifier, the chain extender and the like are added to water, Examples thereof include a method of stirring and mixing.

Hereinafter, the water-based polyurethane composition of the present invention will be described.
The aqueous polyurethane composition of the present invention (hereinafter also referred to as “the composition of the present invention”) is at least one selected from the group consisting of the above-described urethane emulsion of the present invention and an oxazoline group, a carbodiimide group, and an aziridine group. And a crosslinking agent having two or more.

The cross-linking agent used in the composition of the present invention is not particularly limited as long as it is a compound having two or more selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group. Specifically, for example, an aqueous resin and / or emulsion having at least one selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group in the molecule is excellent in compatibility with the urethane emulsion. It is preferable from the point. These may be used alone or in combination of two or more.
Among these, a crosslinking agent having two or more oxazoline groups is preferable because it reacts with a carboxy group at a relatively low temperature.

The aqueous resin is an aqueous resin (water-soluble polymer) having at least two in the molecule selected from the group consisting of an oxazoline group, a carbodiimide group, and an aziridine group. The aqueous resin preferably has an acrylic main chain.
The aqueous resin can be used by dissolving in an appropriate solvent in advance. Specific examples of the solvent include water and water-soluble solvents such as 1-methoxy-2-propanol. At this time, that whose solid content is 5-30 mass% is preferable.

The aqueous resin may be produced by a known method, or a commercially available product may be used.
As commercial products, crosslinkers having an oxazoline group are, for example, Epocross WS-500, Epocross WS-700 (all manufactured by Nippon Shokubai Co., Ltd.), and crosslinkers having a carbodiimide group are, for example, Carbodilite V-02, Carbodilite V -02-L2, Carbodilite V-04 (all manufactured by Nisshinbo Industries, Inc.) and the like.

The emulsion is an emulsion having two or more in the molecule of at least one selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group. The resin component contained in the emulsion preferably has an acrylic main chain.
The emulsion preferably has a solid content of 10 to 60% by mass.

The emulsion may be produced by a known method, or a commercially available product may be used.
Commercially available cross-linking agents having an oxazoline group include, for example, Epocross K-1010E, Epocross K-1020E, Epocross K-1030E, Epocross K-2010E, Epocross K-2020E, Epocross K-2030E (all Nippon Shokubai Co., Ltd.) Manufactured) and the like.

In addition to the above-mentioned commercially available products, XAMA2, XAMA7 (all manufactured by EIT), PFAZ-322 (manufactured by Cyblon Chemicals), etc. as crosslinkers having an aziridin group, UCARLNK Croslinker XL as a crosslinker having a carbodiimide group -29SE (manufactured by Union Carbide), Carbodilite E-01, Carbodilite E-02 (all manufactured by Nisshinbo Co., Ltd.), etc.

  In the composition of the present invention, the molar ratio of the carboxy group of the urethane prepolymer and the total of the oxazoline group, carbodiimide group and aziridine group of the crosslinking agent is 1.0 / 0.5 to 1.0 / 2.0 is preferable, 1.0 / 0.5 to 1.0 / 1.5 is more preferable, and 1.0 / 0.8 to 1.0 / 1.2 is preferable. Further preferred. If the said molar ratio is this range, the hardness improvement effect of the film | membrane by bridge | crosslinking will be large, and the hardened | cured material excellent in water resistance will be obtained. Moreover, it is excellent in storage stability.

  The crosslinking agent reacts with a carboxy group contained in the urethane emulsion. At this time, since the functional group (d) contained in the urethane emulsion acts as a catalyst for this reaction, a film can be formed in a relatively short time.

  In addition to the components described above, the water-based polyurethane composition of the present invention may optionally include a filler, an antioxidant, an antioxidant, a pigment (dye), a plasticizer, a thixotropic agent, an ultraviolet absorber, a flame retardant, Various additives such as a surfactant (including a leveling agent), a dispersant, a dehydrating agent, an adhesion-imparting agent, and an antistatic agent can be contained.

  Examples of the filler include organic or inorganic fillers having various shapes. Specifically, for example, fumed silica, calcined silica, precipitated silica, ground silica, fused silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; calcium carbonate, magnesium carbonate, zinc carbonate; Waxite clay, kaolin clay, calcined clay; carbon black; these fatty acid treated products, resin acid treated products, urethane compound treated products, fatty acid ester treated products and the like.

Specific examples of the anti-aging agent include hindered phenol compounds.
Specific examples of the antioxidant include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).

  Specific examples of the pigment include inorganic pigments such as titanium oxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, etc .; azo pigment, phthalocyanine pigment, quinacridone Pigment, quinacridone quinone pigment, dioxazine pigment, anthrapyrimidine pigment, anthanthrone pigment, indanthrone pigment, flavanthrone pigment, perylene pigment, perinone pigment, diketopyrrolopyrrole pigment, quinonaphthalone pigment, anthraquinone pigment, thioindigo pigment, benzimidazolone Examples thereof include organic pigments such as pigments, isoindoline pigments, and carbon black.

  Specific examples of the plasticizer include diisononyl phthalate (DINP); dioctyl adipate, isodecyl succinate; diethylene glycol dibenzoate, pentaerythritol ester; butyl oleate, methyl acetylricinoleate; tricresyl phosphate, trioctyl phosphate An adipate propylene glycol polyester, an adipate butylene glycol polyester, and the like.

Specific examples of the thixotropic agent include aerosil (manufactured by Nippon Aerosil Co., Ltd.), disparon (manufactured by Enomoto Kasei Co., Ltd.), and the like.
Specific examples of the adhesion-imparting agent include terpene resins, phenol resins, terpene-phenol resins, rosin resins, xylene resins, and the like.

Specific examples of the flame retardant include chloroalkyl phosphate, dimethyl / methyl phosphonate, bromine / phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, brominated polyether, and the like.
Specific examples of the antistatic agent include quaternary ammonium salts; hydrophilic compounds such as polyglycols and ethylene oxide derivatives.

  The method for producing the aqueous polyurethane composition of the present invention is not particularly limited, but the above-described urethane emulsion of the present invention, a crosslinking agent, and various additives as necessary are sufficiently kneaded using a stirrer such as a mixing mixer. Can be used.

  The composition of the present invention can be used for both one-pack type and two-pack type, but when used as a one-pack type, there is no need to mix the main agent and curing agent (crosslinking agent) on site. Excellent in properties. In addition, the composition of the present invention uses a compound having a specific functional group such as an oxazoline group as a cross-linking agent, and the functional group (d) is reacted with a tertiary amine, so that it is storage stable. Excellent. Therefore, the composition of the present invention is preferably used as a one-component type.

  The curing conditions of the composition of the present invention are not particularly limited. For example, by drying at about 60 to 150 ° C. for 1 to 6 hours, a crosslinked film can be formed, and a cured product having excellent water resistance can be obtained. it can.

As described above, in the urethane prepolymer used in the composition of the present invention, the functional group (d) is mainly ionized by reaction with a tertiary amine and / or ammonia, and dispersed in water to form an emulsion. Become.
Since the functional group (d) does not act as a catalyst in an ionized state, the composition of the present invention is excellent in storage stability even when it is in a one-pack type.
In the composition of the present invention, the tertiary amine and the like are volatilized when dried, and the functional group (d) is regenerated.
The regenerated functional group (d) participates as a catalyst in the reaction between a carboxy group and a reactive group (for example, an oxazoline group) of a crosslinking agent described later. Therefore, the composition of the present invention can form a film in a relatively short time, does not cause re-entry of moisture, and can prevent problems such as poor adhesion. Therefore, the composition of this invention can obtain the hardened | cured material which is excellent in water resistance.

  The composition of the present invention is used for a wide range of applications by taking advantage of the above-described excellent characteristics. However, the sealing material for construction, the sealing material for civil engineering, the sealing material for automobiles, various sealing agents, elastic adhesives, various sealing agents. It is preferably used as a potting agent.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Preparation of urethane emulsion (Synthesis Examples 1-2)>
Polyisocyanate compound (A1), polyisocyanate compound (A2), polyol compound (B1), compound (C1) and compound (D1) in the amount (g) shown in Table 1 below (Synthesis Example 2 is not compound (D1)) Addition) The mixture was put into a stirrer and reacted at 70 ° C. for 8 hours under a nitrogen stream to synthesize a urethane prepolymer.
Next, each synthesized urethane prepolymer was dissolved in ethyl acetate (viscosity modifier) without isolation, and then in water with triethylamine and piperazine hexahydrate (chain extender) at 10 ° C. for 1 hour. A urethane emulsion was prepared by stirring and dispersing.
The amounts (g) of ethyl acetate, water, triethylamine and piperazine hexahydrate and the solid content (%) excluding ethyl acetate of each urethane emulsion obtained are shown in Table 1 below.

The components shown in Table 1 are as follows.
Polyisocyanate compound (A1): TDI (Cosmonate TDI100, manufactured by Mitsui Takeda Chemical Company)
Polyisocyanate compound (A2): triisocyanurate of isophorone diisocyanate (VESTANAT T1890, manufactured by Degussa)
Polyol compound (B1): 3-methylpentanediol / AA (Kuraray polyol P2010, number average molecular weight 2000, manufactured by Kuraray Co., Ltd.)
Compound (C1): dimethylol butanoic acid (manufactured by Nippon Kasei Co., Ltd.)
Compound (D1): 1,4-aminosulfonic acid (manufactured by Kanto Chemical Co., Inc.)
Triethylamine: manufactured by Kanto Chemical Co., Ltd. Piperazine hexahydrate (chain extender): manufactured by Nippon Emulsifier Co., Ltd. Ethyl acetate (viscosity modifier): manufactured by Kanto Chemical Co., Ltd.

<Preparation of water-based polyurethane composition (Examples 1 to 6 and Comparative Examples 1 to 8)>
To each of the obtained urethane emulsions, an amount (g) of an oxazoline group-containing emulsion (Epocross K2020E, manufactured by Nippon Shokubai Co., Ltd.) or a carbodiimide group-containing aqueous resin (Carbodilite V-02, manufactured by Nisshinbo Co., Ltd.) is added. And 20 minutes at 20 ° C. to obtain each aqueous polyurethane composition.
Using each composition obtained, water resistance and water resistance after storage were evaluated by the following methods.
The results are shown in Table 2.

(water resistant)
10 g of each composition immediately after being obtained was dried at 80 ° C. for 1 hour to form a sheet-like film having a length of 100 mm × width of 100 mm × thickness of about 0.4 mm to obtain a test piece.
After immersing this test piece in 20 degreeC or 80 degreeC water for 24 hours, the state of the test piece in water was observed visually, and water resistance was evaluated.
“○” indicates that there is no change in appearance compared to before immersion, “△” indicates that part of the film is dissolved and dispersed in water, and “Δ” indicates that the entire film is dissolved and dispersed in water. It was set as “x”.

(Water resistance after storage)
Each composition obtained was allowed to stand at 50 ° C. for 2 weeks, 10 g was dried at 80 ° C. for 1 hour to form a sheet-like film having a length of 100 mm × width of 100 mm × thickness of about 0.4 mm, Then, a test piece was cut into 25 mm × 25 mm × about 0.4 mm.
After immersing this test piece in 80 degreeC water for 24 hours, the state of the test piece in water was observed visually, and water resistance was evaluated.
“○” indicates that there is no change in appearance compared to before immersion, “△” indicates that part of the film is dissolved and dispersed in water, and “Δ” indicates that the entire film is dissolved and dispersed in water. It was set as “x”.

  As is apparent from the results shown in Table 2, Examples 1 to 6 were compared with aqueous polyurethane compositions (Comparative Examples 1 to 8) using a urethane emulsion containing no sulfo group (Synthesis Example 2). The water-based polyurethane composition is excellent in water resistance and can suppress the amount of the crosslinking agent used.

Claims (7)

  A urethane emulsion obtained by reacting a urethane prepolymer having a carboxy group and a functional group having a higher acidity than the carboxy group with a tertiary amine and / or ammonia in water.   The urethane prepolymer is a compound having a polyisocyanate compound (A) having two or more isocyanate groups, a polyol compound (B) having two or more hydroxy groups, a group having reactivity with an isocyanate group, and a carboxy group ( The urethane emulsion according to claim 1, which is obtained by copolymerizing a compound (D) having a group having reactivity with C) and an isocyanate group and a functional group having a higher acidity than a carboxy group.   The urethane emulsion according to claim 1 or 2, wherein the functional group having a higher acidity than the carboxy group is a sulfo group.   The urethane emulsion according to claim 1, wherein the tertiary amine is triethylamine. The urethane emulsion according to any one of claims 1 to 4,
An aqueous polyurethane composition comprising a crosslinking agent having at least one selected from the group consisting of an oxazoline group, a carbodiimide group and an aziridine group.   The water-based polyurethane composition according to claim 5, wherein the cross-linking agent is a water-based resin and / or an emulsion having two or more of at least one selected from the group consisting of an oxazoline group, a carbodiimide group, and an aziridine group.   The molar ratio between the carboxy group of the urethane prepolymer and the total of the oxazoline group, carbodiimide group and aziridine group of the crosslinking agent is 1.0 / 0.5 to 1.0 / 2.0. The water-based polyurethane composition according to 5 or 6.