JP3383980B2 - Aqueous paint composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel and useful aqueous coating composition. More specifically, it comprises an aqueous dispersion (A) of a chlorinated polyolefin graft copolymer as an essential component and an epoxy compound (B), or a chlorinated polyolefin graft as an essential component. It comprises an aqueous dispersion (A) of a copolymer, an epoxy compound (B) and an aqueous dispersion (C) of polyurethane, and can be used particularly as a paint, a printing ink and an adhesive. , Among others,
The present invention relates to an extremely highly practical aqueous coating composition capable of imparting excellent properties such as dispersion stability and durability.

[0002]

2. Description of the Related Art In coating a polyolefin-based substrate, a so-called chlorinated polyolefin-based material such as a blend or graft of chlorinated polyolefin and acrylic resin, carboxylic acid resin, petroleum resin, etc. has hitherto been used. A resin (composition) is used as a binder for a primer or a top coat.

However, the medium used as a binder for this type of polyolefin-based substrate is an organic solvent, which not only deteriorates the working environment and impairs safety for the human body, but also pollutes the atmosphere. In addition to the fact that it is a flammable solvent, there is always a danger of fire and explosion.

The organic solvent liquid of synthetic resin is generally
Since it has a high viscosity, it is difficult to apply it in the form of a high-concentration solution, and it is necessary to use a large amount of solvent in order to obtain an appropriate working viscosity.

As a method of avoiding the disadvantage of such an organic solvent solution of a chlorinated polyolefin resin, for example, a method of dispersing a chlorinated polyolefin resin in water to prepare a paint has been proposed.

Initially, however, the chlorinated polyolefin resin is made water-based by a method of mechanically dispersing the chlorinated polyolefin resin dissolved in a solvent in the presence of an emulsifier or a protective colloid. It was

The aqueous dispersion of the chlorinated polyolefin resin thus obtained has poor storage stability, and it is difficult to remove a large amount of organic solvent. Due to the influence of the emulsifiers and protective colloids used, the resulting coatings have poor adhesion, corrosion resistance or water resistance, so their use has been significantly limited.

[0008]

As described above, according to the prior art, an extremely highly practical aqueous coating composition capable of imparting excellent properties such as dispersion stability and durability. The reality was that it was impossible to obtain it.

[0009] Therefore, the problem to be solved by the present invention depends on the first point, and is excellent in dispersion stability as well as in adhesion and durability, which is a highly practical composition for water-based coatings. It is to provide things.

The inventors of the present invention have focused their attention on the problems to be solved by the invention described above, and have conducted extensive studies. As a result, an aqueous dispersion (A) containing a chlorinated polyolefin graft copolymer, That is, the chlorinated polyolefin graft copolymer aqueous dispersion (A) and polyethylene glycol
Recall diglycidyl ether, polypropylene glyco
Epoxy compound (B) such as diglycidyl ether
And a polyurethane aqueous dispersion (C), wherein the resin composition for water-based coating composition has excellent adhesiveness to a polyolefin-based substrate, solvent resistance, and dispersion stability, among others. Upon finding out, the present invention has been completed here.

[0011]

[Structure] That is, the present invention is a chlorinated polyolefin glass
Aqueous dispersions of shift copolymer 50 to 98 parts by weight of (A) and (solids), polyethylene glycol diglycidyl et
Ether, polypropylene glycol diglycidyl ether
Le, neopentyl glycol diglycidyl ether,
1,6 Hexane glycol diglycidyl ether, green
Serine polyglycidyl ether, trimethylolpropa
Polyglycidyl ether, sorbitol polyglycidyl
Containing 1 to 20 parts by weight of at least one epoxy compound (B) selected from the group consisting of polyethers and 1 to 60 parts by weight of an aqueous polyurethane dispersion (C), and
The total of these is 100 parts by weight,
It is intended to provide an aqueous coating composition having extremely high practicality.

Here, an aqueous dispersion containing the above-mentioned chlorinated polyolefin used in the present invention,
That is, the aqueous dispersion (A) of the chlorinated polyolefin graft copolymer can be produced, for example, by the following method.

That is, a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer (a-2) is copolymerized in the presence of a chlorinated polyolefin resin (a-1) using a radical polymerization initiator, It can be prepared by dispersing a resin composition obtained by neutralizing a part or all of the carboxyl groups with a basic compound in an aqueous medium.

Alternatively, as the chlorinated polyolefin graft copolymer aqueous solution (A), a vinylin monomer mixture containing a monomer having a hydroxyl group is used as a polymerization initiator in the presence of a chlorinated polyolefin resin (a-1). Copolymerization, followed by addition reaction of a carboxylic acid anhydride compound to a hydroxyl group, and then neutralizing a part or all of the carboxylic acid group thus formed with a basic compound. Can be done.

Here, the above-mentioned chlorinated polyolefin resin (a-1) refers to a polyolefin having a chlorination ratio of 50% by weight or less, preferably 10 to 40% by weight, and If only to exemplify a typical polyolefin,
Ethylene, propylene, 1-butene, 3-methyl-1-
Homopolymers or copolymers of various α-olefins such as butene or 3-methyl-1-heptene; or ethylene-vinyl acetate copolymers, ethylene-butadiene copolymers or ethylene-acrylic acid Various copolymers of α-olefins and other vinyl-based monomers such as ester copolymers, and therefore, only representative examples of such chlorinated polyolefins are given. If it just stops, it is chlorinated polyethylene, chlorinated polypropylene, a chlorinated ethylene-propylene copolymer, a chlorinated ethylene-vinyl acetate copolymer, etc.

The chlorinated polyolefin resin (a-
Regarding the chlorination rate of 1), this chlorination rate is 50% by weight.
If it exceeds, the adhesion to the polyolefin-based substrate will inevitably decrease, so the determination of the chlorination rate is based on the determination of various coating performances such as adhesion, flexibility and hardness. It should be done with consideration, preferably 10 to 50% by weight, and more preferably 15 to 40% by weight. A resin composition having

As the above-mentioned carboxyl group-containing vinyl monomers used in the present invention, only typical ones are exemplified, and acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid. Is.

The hydroxy group-containing vinyl monomers to be used in the present invention are not limited to the typical ones, but hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate or methacrylic acid may be used. Hydroxypropyl acid and the like.

Further, only representative examples of other polymerizable vinyl monomers which can be used as the vinyl monomer mixture are shown below. Styrene, vinyltoluene, 2-methylstyrene, tert-
Various styrenic monomers such as butyl styrene or chlorostyrene: methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n acrylate Various acrylates such as hexyl, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate or dodecyl acrylate:

Methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, decyl or methacrylic acid methacrylate. Various methacrylic acid esters such as dodecyl acid: N-methylol (meth) acrylamide or N-
Examples include various N-substituted (meth) acrylic monomers such as butoxymethyl (meth) acrylamide.

Further, only specific examples of the above-mentioned carboxylic acid anhydride compounds are maleic anhydride, phthalic anhydride, anhydrous (meth) acrylic acid, hexahydrophthalic anhydride and the like.

Further, only specific examples of the amino group-containing monomer will be exemplified.
N-dimethylaminoethyl (meth) acrylate, N,
Various tertiary amino group-containing monomers represented by N-diethylaminoethyl (meth) acrylate or N, N-dimethylaminopropyl (meth) acrylate.

As a typical preparation method of the chlorinated polyolefin graft copolymer aqueous liquid (A) used in the present invention, for example, the presence of the chlorinated polyolefin resin (a-1) as described above. In the following, a vinyl monomer mixture containing a carboxyl group-containing vinyl monomer (a-2) is copolymerized with a polymerization initiator to neutralize a part or all of the carboxyl groups with a basic compound. When the obtained resin composition is dispersed in an aqueous medium, the proportion of the carboxyl group-containing vinyl monomer (a-2) used in the vinyl monomer mixture is in the range of 5 to 40% by weight. The inside is appropriate.

When the proportion of the carboxyl group-containing vinyl monomer used is less than 5% by weight, the dispersion stability of the obtained resin composition in the aqueous medium tends to deteriorate, which is not preferable.

On the other hand, when the proportion of the carboxyl group-containing vinyl monomer used exceeds 40% by weight and is used in an excessively large amount, the water resistance of the coating film tends to decrease, which is not preferable.

The other polymerizable vinyl monomers are mainly
For the purpose of adjusting the glass transition temperature of the carboxyl group-containing polymer, that is, the copolymer portion of the carboxyl group-containing vinyl monomer (a-2), and balancing the hydrophilicity and hydrophobicity of the carboxyl group-containing polymer,
Is what is used.

The proportion of the chlorinated polyolefin resin (a-1) and the vinyl monomer mixture used is suitably in the range of 10:90 to 90:10 by weight.
Used in the copolymerization reaction of the vinyl monomer mixture, only typical examples of the polymerization initiator are exemplified, and a typical radical initiator such as azobisisobutyronitrile or benzoyl peroxide is used. Can be mentioned.

The proportion of these polymerization initiators used is as follows:
A suitable range is 0.2 to 20% by weight based on the vinyl monomer mixture. Further, as the chlorinated polyolefin graft copolymer aqueous liquid, for example, a vinyl monomer mixture containing a hydroxyl group-containing monomer (a-3) in the presence of a chlorinated polyolefin resin (a-1),
Copolymerization is performed using a polymerization initiator, and then the carboxylic acid anhydride compound (a-4) is subjected to an addition reaction with a hydroxyl group, and then a part or all of the carboxylic acid group thus produced is converted to a basic compound. In the case of following the method of neutralizing with, the proportion of the hydroxyl group-containing monomer (a-3) used in the vinyl monomer mixture is
The range of 5 to 60% by weight is suitable.

On the other hand, the ratio of the carboxylic acid anhydride compound (a-4) to be used is usually appropriate within the range of hydroxyl group / carboxylic acid anhydride group = 1/1 to 1 / 0.1 (molar ratio). .

As the organic solvent used in the copolymerization reaction, only typical ones are exemplified. Various alcohols such as methanol, ethanol, propanol or butanol; methyl cellosolve, ethyl cellosolve, propyl cellosolve. , Butyl cellosolve, various ether alcohols such as methyl carbitol or ethyl carbitol; various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl propyl ketone or ethyl butyl ketone; or various such as toluene or xylene And aromatic hydrocarbons.

The chlorinated polyolefin graft copolymer aqueous liquid (A) which is particularly useful in the present invention is suitable when the target resin composition obtained by various polymerization reactions as described above contains a carboxylic acid group. A resin is obtained by adding a base in an amount such that the pH of the dispersion is 7 or more, and when the target resin composition contains a basic amino group, an acid in an amount such that the pH of the dispersion is 6 or less. It is obtained by dispersing the composition in an aqueous medium.

As the above-mentioned base used here, it is desirable to use ammonia or volatile amines. However, the use of an inorganic base is not preferable because it tends to remain in the coating film and reduce the water resistance.

On the other hand, if only representative examples of the above-mentioned amines are given, various alkylamines such as trimethylamine, triethylamine or tributylamine; dimethylethanolamine, diethanolamine or aminomethylpropanol. , Various alcohol amines; or morpholine.

If desired, various polyvalent amines such as ethylenediamine or diethylenetriamine can also be used. The aqueous medium referred to in the present invention refers to water or a mixture of water and a hydrophilic organic solvent in which at least 10% by weight is water.

As the hydrophilic organic solvent, only typical ones will be exemplified. Methanol, ethanol,
Various alcohols such as n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol or isobutanol; methyl cellosolve, ethyl cellosolve, propyl cellosolve,
Various ether alcohols such as butyl cellosolve, methyl carbitol, and ethyl carbitol; or various ketones such as acetone or methyl ethyl ketone, as well as dioxane, dimethylformamide, or diacetone alcohol.

The chlorinated polyolefin graft copolymer aqueous dispersion (A) that is particularly useful in the present invention has very good dispersion stability, and it is necessary to reduce the amount of the organic solvent contained. When there is, if so-called low boiling point solvent such as acetone or methyl ethyl ketone, or a solvent such as butanol or toluene that is azeotropic with water as a reaction solvent or a dispersion aid, in the aqueous medium, After being dispersed, the desired chlorinated polyolefin graft copolymer aqueous dispersion (A) having a low organic solvent content can be easily obtained by distillation under normal pressure or reduced pressure. The chlorinated polyolefin graft copolymer aqueous dispersion (A) is appropriately used in an amount of 50 to 98 parts by weight.

Next, the polyurethane aqueous dispersion (C) which is particularly useful in the present invention can be produced by various methods. As a general method for preparing the polyurethane water dispersion (C), a compound having an ionic functional group (reactive polar group) is partially copolymerized during the urethanization reaction, So-called hydrophilic group-containing isocyanate-terminated prepolymers are known to be dispersed in water and then chain-extended with amines, but these reactions are conventionally batch reactions, and usually, It is common to synthesize a urethane prepolymer in a first container, then disperse in water and chain extend with amines in the same or a second container.

The above-mentioned hydrophilic group-containing isocyanate-terminated prepolymer to be used is such that it is produced from a conventionally known polyisocyanate compound and an active hydrogen-containing compound capable of reacting with an isocyanate group.

Of the compounds that can be used as the polyisocyanate compound, only particularly representative ones are exemplified by 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and m.
-Phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate,
2,2'-diphenylmethane diisocyanate, 3,
Starting with 3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate 3,3'-dichloro-4,4'-biphenylene diisocyanate or 1,5-naphthalene diisocyanate ,

Or 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate,
1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine Diisocyanate, isophorone diisocyanate or 4,4'-dicyclohexylmethane diisocyanate 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate and the like.

The compound containing active hydrogen capable of reacting with the above-mentioned isocyanate group used in the production of the isocyanate-terminated prepolymer has an average molecular weight of 3
00-10,000, preferably 500-5,000
Within the range of so-called high molecular weight compounds and molecular weight of 3
It is classified into a so-called low molecular weight compound of 00 or less.

Among them, polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, polyester amide polyols or polythioether polyols are particularly representative as the high molecular weight compound.

As the polyester polyol, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6 -Hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol,
Tetraethylene glycol, molecular weight 300-600
Within the range of 0, polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A or hydroquinone, or alkylene thereof. Various glycol components such as oxide adducts,

Succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4
-Cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid,
2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid or 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid, or anhydrides of various dicarboxylic acids thereof Or ester-forming derivatives;

P-Hydroxybenzoic acid or p- (2-
In addition to polyesters obtained by dehydration condensation reaction with various acid components such as (hydroxyethoxy) benzoic acid or ester-forming derivatives of various hydroxycarboxylic acids thereof, various cyclic compounds such as ε-caprolactone Polyesters obtained by a ring-opening polymerization reaction of an ester compound, or copolyesters thereof are particularly representative.

As the polyether, ethylene glycol, diethylene glycol, triethylene glycol,
Propylene glycol, trimethylene glycol, 1,
3-butanediol, 1,4-butanediol, 1,6
-Hexanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpereropan, sorbitol, sucrose, aconit sugar, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, 1 of various compounds having at least 2 active hydrogen atoms, such as hydroxyphthalic acid or 1,2,3-propanetrithiol
One or two or more kinds of various monomers, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran or cyclohexylene, as an initiator, by an ordinary method. The addition-polymerized form is particularly typical.

As the polycarbonate polyol,
Compounds obtained by reacting various glycols such as 1,4-butanediol, 1,6-hexanediol or diethylene glycol with diphenyl carbonate or phosgene are particularly representative.

On the other hand, a low molecular weight compound has a molecular weight of 30.
A compound having 0 or less and having at least 2 or more active hydrogens in a molecule is referred to, and only typical ones among them are used as a raw material of a polyester polyol. , Various glycol components; various polyhydroxy compounds such as glycerin, trimethylolethane, trimethylolpropane, sorbitol or pentaerythritol; or ethylenediamine, 1,6-hexamethylenediamine,
Piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine,
Various amine compounds such as 1,2-propanediamine, hydrazine, diethylenetriamine or triethylenetetramine.

As a method for introducing a hydrophilic group into the isocyanate group-containing prepolymer having a hydrophilic group, at least one or more active hydrogens are contained in the molecule, and a carboxyl group, a sulfonic acid group, a sulfonate group or ethylene is used. Examples thereof include a method of copolymerizing at least one kind of hydrophilic group-containing compound having an oxide repeating unit at the time of producing the prepolymer.

As typical examples of such hydrophilic group-containing compounds, only 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid,
Various sulfonic acid-containing compounds such as sulfosuccinic acid, 5-sulfoisophthalic acid, sulfanilic acid, 1,3-phenylenediamine-4,6-disulfonic acid and 2,4-diaminotoluene-5-sulfonic acid, or those Polyester polyols obtained by copolymerizing them, including various derivatives of

2,2-Dimethylolpropionic acid, 2,
2-dimethylol butyric acid, 2,2-dimethylol valeric acid,
Dioxymaleic acid, 2,6-dioxybenzoic acid, 3,
Various carboxylic acid-containing compounds such as 4-diaminobenzoic acid, or various derivatives thereof, and further polyester polyols obtained by copolymerizing them; or

A polyethylene-polyalkylene copolymer having a repeating unit of ethylene oxide of at least 30% by weight and having at least one active hydrogen in the polymer and having a molecular weight of 300 to 10,000. Representative examples are various nonionic group-containing compounds such as coalesce and polyester polyether polyols obtained by copolymerizing them, and these may be used alone or in combination of two or more,

In the present invention, particularly preferred hydrophilic group-containing compounds are carboxyl group-containing compounds; or their derivatives or polyester polyols obtained by copolymerizing them.

The content of the hydrophilic group in the isocyanate group-containing prepolymer having a hydrophilic group is such that in the case of a hydrophilic group such as a carboxyl group, a sulfonic acid group or a sulfonate group, the solid content of the finally obtained polyurethane resin is 100.
At least 0.01 equivalent or more per part, preferably,
The range of 0.01 to 0.2 equivalent is suitable, and
In the case of the nonionic group-containing compound, it is appropriate that the content of the non-ionic group-containing compound is at least 3% by weight, preferably 5 to 30% by weight, based on the solid content of the finally obtained polyurethane resin.

The hydrophilic group-containing isocyanate-terminated prepolymer is produced by a conventionally known method. For example, as described above, various polyisocyanate compounds and active hydrogen-containing compounds (including hydrophilic group-containing compounds) are prepared. The equivalent ratio of the isocyanate group and the active water group is 1.1: 1 to 3:
1, preferably at a ratio of 1.2: 1 to 2: 1 at 20 to 120 ° C., preferably 30 to 100 ° C.
It is carried out according to a method such as reacting with.

These reactions can be carried out in the absence of a solvent, but an organic solvent can be used for the purpose of controlling the reaction of the reaction system or reducing the viscosity. As such organic solvents, only representative ones are exemplified, such as toluene or xylene,
Various aromatic hydrocarbons; various ketones such as acetone or methyl ethyl ketone; various ethers such as tetrahydrofuran; various acetic acid esters such as ethyl acetate or butyl acetate; or dimethylformamide or N-methylpyrrolidone And various amides.

As the particularly preferred organic solvent in the present invention, a solvent having a boiling point of 100 ° C. or lower and a hydrophilic solvent is suitable. Of these, particularly representative ones are exemplified by acetone. And methyl ethyl ketone.

When the prepolymer is continuously mixed with the aqueous phase, a suitable viscosity of the prepolymer is 10
Within the range of up to 2,000 cps. Viscosity is 2,000
When it exceeds 0 cps, not only the pressure loss in the pipe becomes large, but also the viscosity difference from the water phase becomes too large, so that the effect of mixing by the mixer becomes insufficient, and as a result, a stable water dispersion is obtained. Can't get

On the other hand, when it is less than 10 cps, the amount of the organic solvent used for dilution is too large, which is not economical. Preferably 20-1,000c
It is in the ps range.

When the prepolymer is continuously mixed with the aqueous phase, the temperature of the prepolymer is appropriately in the range of 5 to 80 ° C, preferably 20 to 60 ° C. If the temperature is lower than 5 ° C., the side reaction with water is suppressed and the reaction with amines proceeds selectively, but the utility cost for cooling increases, which is not economical.

On the other hand, when the temperature exceeds 80 ° C., a side reaction with water is promoted, which tends to coarsen the particle size, which is not preferable. As the above-mentioned polyamine chain extenders used in the present invention, only typical ones are exemplified, ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5. -Dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,
4'-dicyclohexylmethanediamine or 1,4
Various diamines such as cyclohexanediamine;
Of course, various polyamines such as diethylenetriamine, dipropylenetriamine or triethylenetetramine; hydrazines; or acid hydrazides; or water, etc. may be used alone or in combination of two or more kinds.

The polyamine chain extender is used by dissolving it in water as a dispersion medium, which is necessary for obtaining the polyurethane water dispersion (C) of the present invention. The equivalent ratio to the isocyanate groups in the isocyanate-containing prepolymer is 0: 1 to 1
1: 1 range, preferably 0.6: 1 to 0.98:
A range of 1 is suitable.

The amount of water to be used may be a minimum amount that forms an O / W type water dispersion after mixing the prepolymer and the water phase, and is 1 with respect to the solid content of the polyurethane resin.
It is suitable to be in the range of from 0 to 1,000% by weight.

When the hydrophilic group of the isocyanate group-containing prepolymer having a hydrophilic group is a carboxyl group, various tertiary amines such as trimethylamine or triethylamine are used as a neutralizing agent necessary for neutralizing the carboxyl group. , To the carboxyl group in an equivalent ratio of 0.
Within the range of 5: 1 to 1.5: 1, preferably 1: 1 to
The range of 1.3: 1 is suitable, and it is necessary to incorporate such a ratio in the aqueous solution of the above polyamine chain extender.

Such a neutralizing agent may be added in advance to the hydrophilic group-containing isocyanate-terminated prepolymer, but since these tertiary amines are also strong catalysts for the urethanization reaction, a side reaction occurs. It is easy to cause
It is not preferable because the prepolymer tends to be colored.

When the aqueous phase is continuously mixed with the prepolymer, which is a general method, the temperature of the aqueous phase is 0 to 5
A range of 0 ° C., preferably 5 to 40 ° C. is suitable.

When the aqueous phase containing the polyamine chain extender is prepared, the organic solvent / water or the organic solvent / neutralizing agent / water lower layer component, which are distilled off in the subsequent distillation step, respectively, are mixed with water. It is possible to use it instead of a part of.

From the viewpoint of pollution control, the lower layer water has conventionally been treated by activated sludge or incineration, which requires a large amount of cost. However, the polyurethane water dispersion useful in the present invention It can be said that this is an economical process because it becomes possible to recover and reuse the physical properties of (C) without any damage.

In this recovery / reuse, the amount of water charged in the aqueous phase should be adjusted to a desired amount according to the composition of the lower layer water, that is, the content of water. At that time, according to the continuous distillation apparatus used in the present invention,
By fixing the distillation conditions, a distillate having a constant quality can be obtained, and therefore adjustment for recovery and reuse is also easy.

Further, since the lower layer water to be recovered and reused contains a part of the same organic solvent as the prepolymer, when the prepolymer is mixed with the amine-containing aqueous phase, It acts so as to further improve the affinity between the both, and thereby an even more stable water dispersion is obtained.

The polyurethane aqueous dispersion (C) of the present invention
Is usually transferred to the next solvent removal step before the chain extension reaction with amines is completed or after the chain extension reaction is completed.

When the reaction is completed, it is transferred to a tank or a reaction kettle and aged with stirring or in a standing state. Polyurethane aqueous dispersion (C) thus obtained
Has a solid content of about 15 to 60%, preferably 20 to 50.
%, Which is a substantially solvent-free water dispersion, but when an organic solvent having a boiling point of 100 ° C. or higher is used, it contains up to 20% of the organic solvent based on the weight of the water dispersion. Even if you do, there is no problem.

The polyurethane aqueous dispersion (C) is to be used when low temperature flexibility and impact resistance are required, such as for automobile polypropylene polypropylene bumpers. Is appropriately in the range of 1 to 60 parts by weight, preferably 1 to 50 parts by weight.

If it is used in an excessively large amount in excess of 60 parts by weight, the adhesion to the polyolefin material and the water resistance will inevitably decrease, which is not preferable. Then, the above-mentioned epoxy compound (B) is polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6 hexane glycol diglycidyl ether, glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether. ,
Selected from the group consisting of sorbitol polyglycidyl ether
At least one compound .

The amount used is appropriately in the range of 1 to 20 parts by weight, and when it is less than 1 part by weight, the solvent resistance and durability of the resulting coating film are inevitably impaired. On the other hand, when it is used in an excessively large amount exceeding 20 parts by weight, the adhesion to the polyolefin material and the water resistance are inevitably deteriorated.

The thus obtained aqueous coating composition of the present invention is mainly applied as a coating for metal coating such as an undercoating agent for automobile parts or a coating for plastics. Can be done. However, the composition of the present invention is not limited to these applications.

[0077]

EXAMPLES Next, the present invention will be described more specifically with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited thereto. In the following, all parts and% are based on weight unless otherwise specified.

Reference Example 1 [Preparation Example of Aqueous Dispersion Liquid (A) of Chlorinated Polyolefin Graft Copolymer] In a nitrogen-substituted four-necked flask, "Super Clone 8
32 L ”[chlorinated polypropylene resin manufactured by Sanyo Kokusaku Pulp Co., Ltd.] and 81.7 parts of toluene and 91.7 parts of toluene are charged and heated to 80 ° C. to completely dissolve.

While stirring the contents at the same temperature, 20 parts of methyl methacrylate and 45 parts of n-butyl acrylate were added.
Parts, 10 parts of β-hydroxyethyl acrylate and 3 parts of benzoyl peroxide were added to 2 parts of a mixture.
The solution was added dropwise over a period of time, and stirring was continued at the same temperature for 3 hours.

The reaction mixture thus obtained is then
After adding 12 parts of phthalic anhydride, the temperature was raised to 100 ° C., and the reaction was further continued for 2 hours. After cooling to 50 ° C., dilute ammonia water prepared by diluting 5 parts of 28% ammonia water with 280 parts of water in advance,
When the solution was added dropwise over 30 minutes, a dispersion liquid was obtained.

Thereafter, the organic solvent contained therein was distilled off from this dispersion by vacuum distillation to contain a chlorinated polyolefin having a solid content of 30.7% and a pH of 8.2. An aqueous dispersion was obtained.

The average particle size of this aqueous dispersion was 0.5 micron (μm) and had a sharp distribution, and even after standing for 1 month, there was still no sediment and it was good. It was confirmed that it had the following stability.

Reference Example 2 (Same as above) In a four-necked flask which had been purged with nitrogen, "Super Clone 8
100 parts of "32 L" and 80 parts of toluene are charged,
It was heated to 0 ° C. and completely dissolved.

At the same temperature, while stirring the contents, a mixture of 15 parts of methyl methacrylate, 48.3 parts of cyclohexyl methacrylate, 6.6 parts of methacrylic acid and 4 parts of benzoyl peroxide was added. The mixture was added dropwise over a period of time, and stirring was continued at the same temperature for 3 hours.

Next, after cooling to 50 ° C., diluted ammonia water prepared by diluting 5 parts of 28% ammonia water with 280 parts of water beforehand was added dropwise over 30 minutes. Was obtained.

Thereafter, the organic solvent contained therein was distilled off from this dispersion by vacuum distillation to contain a chlorinated polyolefin having a solid content of 28.0% and a pH of 8.2. An aqueous dispersion was obtained.

The aqueous dispersion had an average particle size of 0.5 μm and had a sharp distribution, and even after being allowed to stand for 1 month, there was still no sediment and good stability. Was confirmed to have.

Reference Example 3 [Preparation example of polyurethane aqueous dispersion (C)] Polyester (1,6-hexanediol / neopentyl glycol / adipic acid) having a molecular weight of 2,000.
3,120 parts of 1,165 parts of 1,4-butanediol,
A prepolymer having an NCO content of 2.8%, obtained from 215 parts of dimethylolpropionic acid, 1,313 parts of tolylene diisocyanate and 2,591 parts of methyl ethyl ketone, and 194 parts of anhydrous piperazine, of triethylamine An aqueous solution obtained by uniformly dissolving 356 parts and 8,168 parts of water was transferred from each tank to a mixer for mixing.

The aqueous dispersion thus obtained was subsequently subjected to continuous solvent removal under reduced pressure. The finally obtained polyurethane water dispersion had a solid content of 40.5% and a PH of 8.6.

The average particle size of this water dispersion is 0.2.
μm, which has a sharp distribution,
After standing for 1 month, there was still no precipitate,
It was confirmed to have good stability.

Examples 1 and 2 and Comparative Examples 1 and 2 Various paints were prepared with the formulations shown in Table 1.
With respect to each paint, various performances of the coating film were evaluated. The results are shown together in the same table.

[0092] *); Denacol EX-614 (sorbitol polyglycine
Zil ether)

<< Footnote in Table 1 >> Adhesion ………… Air sprayed on polypropylene plate,
After baking at 80 ° C. for 30 minutes, the mixture was allowed to stand at room temperature for 7 days, and then a cross-cut test was performed. Furthermore, it was immersed in 40 ° C. warm water for 240 hours, and the results of the cross-cut test were used.
The secondary adhesion was used.

Gasoline resistance: A coated plate was prepared in the same manner as the adhesion, and the appearance of the coating film was evaluated after dipping in gasoline for 30 minutes.

[0095]

EFFECT OF THE INVENTION The aqueous coating composition of the present invention is particularly excellent in dispersion stability and also excellent in adhesion to a polyolefin-based substrate, solvent resistance and durability. In particular, it was difficult to coat polypropylene or bumper for automobiles, which is a polypropylene substrate among polyolefin substrates, which was difficult in the past, when it was used as a primer for paints, or when a polypropylene film was used as a substrate for paper and other materials. When it is used as an adhesive for laminating the film of (1), it is possible to easily impart extremely excellent adhesion and durability that can be practically used.

The aqueous coating composition of the present invention not only facilitates coating and adhesion to a polyolefin substrate, but also as an impregnating treatment agent for a polyolefin substrate, or as a coating agent, adhesive agent, coating agent, It can be widely used as various base resins for water-based paints, water-based inks and sizing agents.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C09D 151/06 C09D 163/00 C09D 175/04

Claims (4)

(57) [Claims] 1. A 50 to 98 parts by weight of the aqueous dispersion of the chlorinated polyolefin graft copolymer (A) and (solids), Po
Polyethylene glycol diglycidyl ether, polypro
Pyrene glycol diglycidyl ether, neopentyl
Glycol diglycidyl ether, 1,6-hexane green
Cold diglycidyl ether, glycerin polyglycidy
Ruther, trimethylolpropane polyglycidyl ether
Ether, consisting of sorbitol polyglycidyl ether
At least one epoxy compound (B) selected from the group
1 to 20 parts by weight and 1 to 60 parts by weight of the aqueous polyurethane dispersion (C), and the total of these is 10
A water-based coating composition, characterized in that it is 0 part by weight. 2. A polyurethane aqueous dispersion (C) as described above.
Has an active hydrogen atom reactive with at least two isocyanate groups in one molecule and has a molecular weight of 300 to 20,0.
No. 00, an aqueous dispersion of a polyurethane resin prepared by subjecting an active hydrogen-containing compound, an organic polyisocyanate compound, and, optionally, a chain extender having an active hydrogen atom reactive with an isocyanate group to an isocyanate polyaddition reaction. The aqueous coating composition according to claim 1, which is a liquid, which is an aqueous dispersion of a polyurethane resin containing a salt-forming group in a polymer chain. 3. A vinyl monomer mixture containing a carboxyl-containing vinyl monomer is copolymerized in the presence of a chlorinated polyolefin in which the chlorinated polyolefin graft copolymer aqueous dispersion (A) has a chlorination rate of 50% by weight or less. And a resin composition obtained by neutralizing a part or all of the carboxyl groups with a basic compound,
The dispersion according to claim 1, which is dispersed in an aqueous medium.
The water-based coating composition described. 4. A vinyl monomer mixture containing a vinyl monomer having a hydroxyl group is added in the presence of a chlorinated polyolefin having a chlorination ratio of 50% by weight or less in the aqueous dispersion (A) of the chlorinated polyolefin graft copolymer. Polymerization, then, addition reaction of the carboxylic acid anhydride compound to the hydroxyl group, and then part or all of the generated carboxylic acid group is neutralized with a basic compound to obtain a resin composition, The aqueous coating composition according to any one of claims 1 to 3, which is dispersed in the composition.