JPH03124779A - Water-based coating composition for plastic base material and formation of coating film - Google Patents

Abstract

PURPOSE:To improve adhesion to a plastic base material and a top coat coating film by incorporating an aq. product of an olefin resin and a urethane resin as vehicle ingredients. CONSTITUTION:An olefin resin (a) with a number-average mol.wt. of 3,000-50,000 which is a polymer wherein an olefin monomer and/or a diene monomer are essential monomer ingredients and a urethane resin (b) with a number-average mol.wt. of 10,000-100,000 which is a urethane prepolymer obtd. by reacting an ingredient (i) contg. 2 or more active hydrogen atoms on average in the molecule with a polyisocyanate ingredient (ii) or a urethan polymer obtd. by reacting a prepolymer obtd. by reacting the ingredients (i) and (ii) with an ingredient for a chain extender (iii) are mixed. Then, a surfactant and/or a neutralizing agent (c) are added thereto and dispersed in water to obtain a vehicle ingredient with a mean particle diameter of 0.001-5mum which is an aq. product of the ingredients (a) and (b). The ingredient and, if necessary, a coloring pigment, an extender pigment, a coating surface modifier, an anti-blistering agent, a plasticizer, etc., are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an aqueous coating composition for plastic substrates and a method for forming a coating film.

BACKGROUND OF THE INVENTION Conventional techniques and their problems Conventionally, plastics, particularly polypropylene resin molded products, have been widely used as base materials for automobiles, home appliances, and general industry. A plastic coating composition is applied to the surface of the polypropylene resin molded product for the purpose of imparting color and durability.

However, the coating film formed from the coating composition generally does not have good adhesion to polypropylene resin, so in order to improve the adhesion, an undercoat coating composition is applied to the polypropylene resin.

As such an undercoat paint composition, a solution in which a modified polyolefin resin such as chlorinated polypropylene is dissolved in an organic solvent is usually used.

However, the modified polyolefin resin used in the coating composition has a high molecular weight to the extent that it does not cause coating film defects such as cracking and peeling even when the object is deformed by external force. In order to dilute this material to a coating viscosity, a large amount of organic solvent is required. For this reason, the coating composition contains a large amount of organic solvent compared to conventional organic solvent-based coating compositions, which reduces the safety and health of coating workers during coating, reduces environmental pollution after coating, and prevents coating and baking. However, there are still problems in terms of safety such as fire and explosion, and there also remains the problem that the coating film formed from the undercoat composition does not have sufficient adhesion to the topcoat film.

In addition, as an aqueous undercoating composition containing no organic solvent, an aqueous polyurethane resin containing polyoxytetramethylene glycol as a polyol component was disclosed in Japanese Patent Application Laid-Open No. 59-113015.
It is stated in the No.

However, there is a problem in that the coating film formed from this composition has poor adhesion to polypropylene resin.

Means for Solving the Problems The present inventor has developed an aqueous paint composition that can form a paint film with excellent adhesion to a plastic substrate and a topcoat film, and a paint film using the paint composition. We have been conducting extensive research in order to find a way to form it.

As a result, the inventors found that the above object can be achieved by a water-based coating composition containing a water-based product of an olefin resin and a urethane resin as a vehicle component, thereby completing the present invention.

That is, the present invention provides an aqueous coating composition for plastic substrates, characterized in that the vehicle component is an aqueous version of an olefin resin and a urethane resin, and a method for applying the coating composition to a plastic substrate and drying it. The present invention relates to a method for forming a coating film, which comprises applying a top coating composition and drying the coating composition.

The olefin resin used in the composition of the present invention is a polymer containing an olefin monomer and/or a diene monomer as an essential monomer component. Specifically, propylene-ethylene copolymer, chlorinated polypropylene, EPDM (ethylene-propylene-diene copolymer), polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc., and these and malein. Examples include acid group-containing polymers obtained by polymerizing acid, maleic anhydride, acrylic acid, methacrylic acid, and other acid group-containing polymerizable unsaturated monomers. Among them, chlorinated polypropylene and (
An acid group-containing polymer obtained by polymerizing maleic acid (anhydride) is particularly suitable for chlorinated polypropylene (preferably a chlorination rate of 20
~30% by weight) component shows excellent adhesion to the propylene base material, and the (anhydrous) maleic acid component shows excellent adhesion to the top coat and has excellent water resistance etc. It is desirable to use this material because it has the advantage of less deterioration due to adhesion. When the (anhydrous) maleic acid component is used, it is usually 0.5 to 10% by weight, preferably about 1 to 10% by weight based on the acid group-containing polymer.
It can be used in a range of 5% by weight.

The olefin resin has a number average molecular weight of about 3000 to
50,000, preferably in the range of about 10,000 to 30,000. If the molecular weight is less than about 3,000, the coating film will tend to stick, attracting foreign matter such as dust and dirt, and the appearance of the final topcoat film will deteriorate, and the plastic substrate after the water resistance test will deteriorate. This is not preferable because it has the disadvantage of deteriorating the adhesion to the surface. On the other hand, if the molecular weight is greater than about 50,000, it is not preferred because a coating film with excellent smoothness cannot be obtained.

The urethane resin, which is a vehicle component used in combination with the olefin resin, is obtained by reacting (1) a component containing an average of two or more active hydrogens per molecule and (2) a polyisocyanate component. It is a urethane polymer, or a urethane polymer obtained by reacting a prepolymer obtained by reacting components (1) and (2) with a chain extender component. Further, these urethane resins may contain acid groups.

Component (1) can be used without any limitation as long as it contains an average of two or more active hydrogens (preferably hydroxyl groups) in one molecule.

Specifically, the following can be mentioned.

(i) Diols: for example ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,
4-butylene glycol, 1,5-pentadiol, neopentyl glycol, 1,6-hexane glycol,
2,5-hexanediol, dipropylene glycol,
2゜2.4-trimethyl-1,3-pentadiol, tricyclodecane dimetatool, 1,4-cyclohexane dimetatool, etc.

(ii) Polyether diol: For example, the above (i)
Those obtained by ring-opening polymerization or ring-opening copolymerization (block or random) of alkylene oxide adducts of diols, alkylene oxides, cyclic ethers (such as tetrahydrofuran), such as polyethylene glycol,
Polypropylene glycol, polyethylene-propylene (block or random) glycol, dioxytetramethylene glycol, dioxyhexamethylene glycol, dioxyoctamethylene glycol, etc.

(iii) Polyester diols: (anhydrous) dicarboxylic acids (e.g. adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycols [e.g. ethylene glycol, propylene glycol, 1,4-butane Diol, 1.6-hexanediol, 1.8-octamethylenediol, neopentyl glycol, bishydroxymethylcyclohexane,
Bishydroxyethylbenzene, alkyl dialkanolamine, m-xylylene glycol, 1,4-bis(
2-hydroxyethoxy)benzene, 4,4'-bis(2-hydroxyethoxy)-diphenylpropane, etc.], such as polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyethylene /propylene adipate, bishydroxymethylcyclohexane and 04-C
Polyester diols consisting of a mixture of 8 linear dicarboxylic acids (e.g.
polylactone diol (for example, polycaprolactone diol and a mixture of two or more thereof), etc.

(iv) Polyether ester diol: ether group-containing diol (the above polyether diol, diethylene glycol, triethylene glycol, dipropylene glycol, etc.) or a mixture of these and other glycols with the above dicarboxylic acid or (anhydrous) dicarboxylic acid compound (phthalic anhydride, maleic anhydride, etc.) and those obtained by reaction with alkylene oxides, such as poly(polyoxytetramethylene) adipate.

(V) Polycarbonate diol formula % formula % (1) (wherein R is a residue of a saturated aliphatic diol of 01 to 12,
X indicates the number of repeating units in the molecule, and is usually an integer of 5 to 50). The compound is a saturated aliphatic diol (1.4-butanediol, 1,5-bentanediol, 1.6-hexanediol, polyethylene glycol such as diethylene glycol, polypropylene glycol, (oxyethylene oxypropylene copolymer diol, etc.) and substituted carbonates (diethyl carbonate, diphenyl carbonate, etc.)
It can be obtained by a transesterification method in which the saturated aliphatic diol is reacted with phosgene, a method in which the saturated aliphatic diol is reacted with phosgene, or a method in which a saturated aliphatic diol is further reacted if necessary.

The diols described in (i) to (V) above can be used alone or in combination of two or more.

Also, among the diols described in (1) to (V) above, those described in (i) to (iii) are preferable, and more preferably the number average molecular weight is about 5,000 or less, preferably about 10
Examples include those in the range of 00 to 3000.

In addition to the diols mentioned above, (Vi) a low molecular weight polyol containing three or more hydroxyl groups in one molecule (preferably number average molecular weight of 500 or less) can be blended.

When the low molecular weight polyol (Vi) is used, for example, the molecular skeleton of the urethane resin has branching properties to form a three-dimensional structure in the urethane resin, thereby improving the water dispersion stability of the polyurethane particles, It has the advantage of improving the water resistance and chemical resistance of the coating film.

Examples of the (1) low molecular weight polyol include trimethylolpropane, trimethylolethane, glycerin, tris-2-hydroxyethyl isocyanurate,
Pentaerythritol etc. can be used. The low molecular weight polyol (Vi) can be blended in an amount of about 0.1 mol or less per 1 mol of the diol component. The compounded metal is approximately 0.1
If the amount is more than mol, it is not preferable because the storage stability of the aqueous compound or the physical properties of the coating film may deteriorate.

As the polyisocyanate component (2) to be reacted with the component (1), a compound containing an average of two or more isocyanate groups in one molecule can be used. Specifically, as aliphatic diisocyanate compounds, aliphatic diisocyanates having 1 to 12 carbon atoms, such as hexamethylene diisocyanate, 2°2.4-1-limethylhexane diisocyanate, lysine diisocyanate, etc.; as alicyclic diisocyanate compounds, carbon atoms 4-18 cycloaliphatic diisocyanates, such as 1,4-cyclohexane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate), 4°4'-dicyclohexylmethane diisocyanate, methyl Cyclohexylene diisocyanate, isopropylidene dicyclohexyl-4,4
'-diisocyanate, etc.; aromatic isocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, meta-xylylene diisocyanate, etc.
Furthermore, modified products of these diisocyanates (carposiimide, uretdione, uretimine-containing modified products, etc.);
and mixtures of two or more thereof.

Any conventional method can be used to introduce acid groups into the urethane resin, but for example, replacing dimethylolalkanoic acid with part or all of the glycol components described in (ii) to (iV) above. By introducing a carboxyl group into polyether diol, polyester diol, polyether ester diol, etc. in advance, or by using a mixture of the diol component (i) or (V) and dimethylolalkanoic acid, acid A method of introducing a group is preferred. Examples of such dimethylolalkanoic acids include dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, and dimethylolvaleric acid.

Urethane resins with acid groups introduced can be dispersed in water without the use of surfactants or with a reduced amount of surfactants, which has the advantage of improving the water resistance of the coating film. be. The content of acid groups is about 25 to 150, preferably about 30 to 100, as the acid value of the urethane resin.
More preferably, the range is about 50 to 80. If the acid value is less than about 25, the water dispersibility will be poor, while if the acid value is more than about 150, the water resistance of the coating film may be poor, which is not preferred.

Urethane resin usually has a number average molecular weight of 10,000 to
100,000, preferably about 20,000 to 50,000,
More preferably, one having a molecular weight of 25,000 to 35,000 can be used. The reaction between component (1) and component (2) results in a urethane prepolymer (usually a number average molecular weight of 10
00 to 3000), the molecular weight may be adjusted to the above range by chain elongation. If the number average molecular weight of the urethane resin is less than about 10,000, water resistance, flexibility, etc. may deteriorate, while if it is greater than 100,000, this may cause sedimentation, aggregation, etc. during paint storage.
It may cause defects such as spots on the paint film, or
This is not preferred because the smoothness of the coating film may deteriorate.

The chain extension method of the urethane prepolymer may be carried out according to a known method. For example, water, water-soluble polyamines, glycols, etc. may be used as the chain extender component, and the urethane prepolymer and the chain extender component may be reacted (a reaction catalyst may be used if necessary). The water-soluble polyamine may contain a primary amino group and/or a secondary amino group.
Polyamine compounds having two or more polyamines in the molecule can be used, such as water-soluble polyamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, xylylenediamine, diethylenetriamine, and triethylenetetramine, and water-soluble alicyclic rings such as piperazine. Formula polyamines and mixtures thereof can be suitably used.

Examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, butanediol, hexanediol,
Trimethylolpropane and the like can be suitably used.

As reaction catalysts, trialkylamines such as trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine; N-alkylmorpholines, such as N-methylmorpholine, N-ethylmorpholine; N-dialkylalkanolamines, For example, N-dimethylethanolamine, N-
Examples include diethylethanolamine; N-alkylvinylpyrrolidone and mixtures of two or more thereof.

The method for making the olefin resin and urethane resin water-based may be any conventionally known method, but for example: After that, a surfactant and/or neutralizing agent is added and dispersed in water.

■ After mixing the urethane resin raw materials (1) and (2) with the olefin resin, <1) and (2)
) A method of reacting the components (so that they are substantially free of isocyanate groups), then adding a surfactant and/or a neutralizing agent, and dispersing them in water.

■ A surfactant and/or neutralizing agent is added to an olefin resin and dispersed in water, and a surfactant and/or neutralizing agent is added to a urethane resin (substantially containing no isocyanate groups). A method of adding and mixing with water and dispersing it.

■ NCO group-containing urethane prepolymer (usually NGO
10H (equivalent ratio in the range of 1.1 to 1.9) is mixed with an olefin resin, dispersed in water, and simultaneously subjected to a chain extension reaction. In this method, a chain extender outside the waterside may be added at the same time, and if necessary, a chain extension reaction catalyst, a surfactant, a neutralizing agent, etc. may also be added.

■ After mixing the (1) component and (2) component of the urethane resin raw material with the olefin resin, +11 component and (2)
) components to obtain a mixture of NCO group-containing urethane prepolymer (NGO10H equivalent ratio of about 1.1 to 1.9) and olefin resin, and then water dispersion and chain elongation in the same manner as in (1) above. A method in which the reactions are carried out at the same time, (1) a method in which the NCO group-containing urethane prepolymer is subjected to a chain extension reaction in the same manner as in (2) above, and simultaneously dispersed in water, and (2) a method in which the olefin resin described in (1) is dispersed in water. A mixing method etc. can be suitably applied.

The neutralizing agent is used when acid groups are present in the urethane resin, olefin resin, urethane prepolymer, etc., and the same neutralizing agent as the above-mentioned chain extension reaction catalyst can be used. Among these, preferred are trialkylamines,
N-alkylvinylpyrrolidone is particularly preferred, and triethylamine is particularly preferred. The amount of neutralization is about 0.5 to 2.0 equivalents, preferably 1 equivalent per equivalent of carboxyl group.
The amount may be approximately 1.5 equivalents.

Examples of surfactants include higher alcohols, alkylphenols, arylphenols, nonionic surfactants such as ethylene oxide adducts such as polyoxypropylene glycol, alkylphenols, sulfate salts of ethylene oxide adducts such as higher alcohols, and alkylbenzene sulfones. Anionic surfactants such as acid salts, and mixtures thereof are preferred. Further, from the viewpoint of water resistance of the coating film, the blending ratio of the surfactant is preferably about 10 parts by weight or less, preferably about 5 parts by weight or less, based on 100 parts by weight of the resin solid content.

Among the above, using those obtained by chain extension reaction can help water dispersion of polyolefin resin, stabilize the resin particles, and have water resistance and
It has the advantage of producing a coating film with excellent performance such as appearance. The polyurethane polymer obtained by carrying out the chain extension reaction is preferably one containing acid groups.

The blending ratio of the olefin resin and the urethane resin, which are the vehicle components of the coating composition of the present invention, is about 5 to 40% by weight, preferably about 10 to 30% by weight, and about 95 to 60% by weight of the latter, both calculated in terms of resin solid content. % by weight, preferably about 90-70
A weight percent range is desirable. Polyolefin resin is about 5
If the olefin resin is less than about 40% by weight or the urethane resin is more than about 95% by weight, the adhesion to the plastic substrate will decrease, while if the olefin resin is more than about 40% by weight or the urethane resin is about 60% by weight. If the amount is less, the adhesion to the top coat, water resistance, storage stability of the paint, etc. will deteriorate, which is not preferable.

In the composition obtained by making it water-based by the above-mentioned methods ① to ②, the urethane resin component is used as a component to assist in the water dispersion of the olefin resin and to stabilize the olefin resin particles. Further, an aqueous dispersion of a urethane resin can be mixed with the aqueous olefin resin as a component having a function of improving coating performance.

As the aqueous dispersion of urethane resin used to improve coating film performance, the same aqueous dispersion of urethane resin as described in the above-mentioned aqueous conversion method can be used.

The urethane resin (hereinafter referred to as urethane resin A) contained in the aqueous mixture of the urethane resin and olefin resin obtained in steps (1) to (3) above, and the urethane resin added to this aqueous mixture to improve coating film performance. A preferred combination of the urethane resin (hereinafter referred to as urethane resin B) in the water dispersion of is a monomer having good compatibility with the olefin resin, such as an aliphatic or alicyclic polyol as the component (1). , a urethane resin obtained by using an aliphatic or alicyclic diisocyanate compound as the component (2) is used as the urethane resin A, and a urethane that uses a large amount of monomers with excellent physical properties, such as aromatic diisocyanates as the component (2). system resin with a number average molecular weight of 20,000 or more, preferably 30,000 to 100
A combination of using a urethane resin of No. 000 as the urethane resin B is mentioned. In addition, the blending ratio of these is such that the ratio of olefin resin/urethane resin A/urethane resin B is approximately 5% based on the solid content of these resins.
~40wt%/15-60wt% 10-80wt%, preferably about 10-30wt%/20-50wt%/20
The content may be 70% by weight.

In addition, the aqueous compound used in the composition of the present invention has storage stability,
Approximately 0.001 to 5μ from the viewpoint of compatibility, coating surface smoothness, etc.
m1 preferably has an average particle size of about 0.05 to 2.0 μm.

In the composition of the present invention, coloring pigments, extender pigments, coating surface conditioners, anti-wrinkle agents, fluidity control agents, anti-cissing agents, plasticizers and the like can be added as necessary.

In order to form a coating film on a plastic substrate using the coating composition of the present invention, the composition of the present invention is applied to the plastic substrate, dried, and then an intermediate coating is applied as needed, and dried or Just apply the top coat while it is wet and let it dry.

It can be used as a plastic base material without any particular restrictions.
Specifically, polypropylene, ethylene-propylene copolymer, EPDM, polyamide, polyester, polyphenylene oxide, acrylonitrile-styrene-butadiene copolymer, polycarbonate, ethylene-vinyl acetate copolymer, unsaturated polyester, polyurethane, reinforced polyurethane. Plastics such as can be used.

These plastic base materials may be those that have been washed or chemically treated with an alkali, acid, organic solvent, etc., if necessary.

The coating composition of the present invention usually contains about 20 to 50% heavy metal solids,
It is used after adjusting the viscosity to about 500 to 2000 centipoise (B-type viscometer, rotation speed 6 RPM).

The means for coating the plastic substrate is not particularly limited, but specifically, spray coating, brush coating, dip coating, electrostatic coating, etc. can be used. Moreover, the coating film thickness is usually about 5 to 50 μm, preferably 10 to 20 μm, based on the dry film thickness. This coating film can then be dried at a temperature ranging from room temperature to 160°C, preferably from about 80 to 120°C.

As the intermediate coating, a known intermediate coating that has excellent adhesion, smoothness, sharpness, weather resistance, etc. can be used.

Specifically, thermosetting intermediate coatings whose vehicle main components are short oil or ultra-short oil alkyd resins having an oil length of 30% or less or oil-free polyester resins and amino resins are mentioned. These alkyd resins and polyester resins preferably have a hydroxyl value of 60 to 140 and an acid value of 5 to 200, and use unsaturated oil (or unsaturated fatty acid) as the modified oil. Etherified melamine resins, urea resins, and benzoguanamine resins (preferably those having 1 to 5 carbon atoms) are suitable. The blending ratio of these two resins should be 65 to 85%, especially 70 to 80%, for the alkyd resin and/or oil-free polyester resin, and 35 to 15%, especially 30 to 20% for the amino resin, based on the solid weight. is preferred. Furthermore, at least a portion of the above amino resin can be replaced with a polyisocyanate compound or a blocked polyisocyanate compound.

Further, the form of the intermediate coating can be conventionally known such as organic solvent type, non-aqueous dispersion type, high solid type, aqueous solution type, aqueous dispersion type, powder type, etc. using the above-mentioned vehicle components. . Furthermore, extender pigments, coloring pigments, other paint additives, and the like can be added to the intermediate paint as necessary.

These intermediate coating paints are paints that are applied to the coating surface formed from the coating composition of the present invention, and the coating can be performed by the same method as described above, and the coating film thickness is determined after curing. It is preferably in the range of 10 to 50 μm based on the coating film, and the curing temperature of the coating film varies depending on the vehicle component, and when curing by heating, it is 60 to 160°C, particularly 80 to 150°C.
It is preferable to heat at a temperature in the range of .

The top coating is a coating that is applied to a coating surface or an intermediate coating surface formed from the coating composition of the present invention, and is used to impart cosmetic properties to the object to be coated.

Specifically, finished appearance (sharpness, smoothness, gloss, etc.), weather resistance (gloss retention, color retention, chalking resistance, etc.)
, paints known per se that form coating films with excellent chemical resistance, water resistance, moisture resistance, hardening properties, etc. can be used, for example,
Examples include paints whose vehicle main components are amino-acrylic resins, amino-alkyd resins, amino-polyester resins, etc. Furthermore, some or all of these amino resins can be converted into polyisocyanate compounds or block polyisocyanate compounds. Alternative paints can also be applied. The form of these paints is not particularly limited, and any form such as organic solution type, non-aqueous dispersion type, water-soluble (dispersed) wave type, powder type, high solid type, etc. can be used. Drying or curing of the coating film is carried out by drying at room temperature, heating drying, irradiation with active energy rays, etc.

The top coat used in the present invention may be either an enamel paint containing a metallic pigment and/or a colored pigment in a paint whose main component is the vehicle described above, or a clear paint containing no or almost no pigments. It may be.

Examples of methods for forming a top coat film using these paints include the following methods: (a) A metallic paint prepared by blending a metallic pigment and, if necessary, a colored pigment, or a blending of a colored pigment. A method of applying solid color paint and curing it by heating (metallic or solid color finish using 1 coat 1 beta method)
.

(b) A method in which metallic paint or solid color paint is applied, heat cured, and then clear paint is applied and heat cured again (metallic or solid color finish using a two-coat, two-bake method).

(C) A method in which a metallic paint or solid color paint is applied, then a clear paint is applied, and then both coatings are cured simultaneously by heating (metallic or solid color finishing using a two-coat one-bake method).

These top coat paints are preferably applied by spray painting, electrostatic painting, or the like. Furthermore, based on the dry film thickness, the coating film thickness is in the range of 25 to 40 μm in (a) above, and in the range of 10 to 30 μm for metallic paints and solid color paints in (b) and (C) above, and in the range of 10 to 30 μm for clear paints. is preferably in the range of 25 to 50 μm. The heat curing conditions can be arbitrarily selected depending on the material of the object to be coated, vehicle components, etc., but generally 60 to 160°C, especially 100°C.
Preferably, heating is performed at ~150°C for 10-40 minutes.

Further, when the coating composition of the present invention contains conductive powder, an intermediate coat or top coat can be electrostatically applied to a plastic substrate coated with the coating composition.

Effects of the Invention The composition of the present invention is an aqueous paint composition using a combination of an olefin resin and a urethane resin as vehicle components, and has excellent paint storage stability and film performance (particularly for plastic substrates and top coats). It has excellent adhesion, bending resistance, water resistance, topcoat appearance, etc.).

EXAMPLES Next, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples. Note that both parts and percentages are based on weight.

Production example number average molecule f of urethane prepolymer (A-1)
225 parts of polybutylene adipate with f12000, polycaprolactone diol with number average molecular weight f12000 3
75 parts, 1,4-cyclohexane dimetatool 26.6
raw material (NGOl
oH-1,57) was charged into a polymerization container, the temperature was raised to 50°C in a nitrogen gas atmosphere with stirring, 0.05 part of dibutyltin oxide was added as a polymerization catalyst, and the mixture was then reacted at 70°C for 1 hour. Therefore, the terminal N with an NCO group content of 36%
A GO group urethane prepolymer (A-1) was obtained. The number average molecular weight was 2150.

Production side of urethane resin emulsion (a-1) 350 parts of the urethane prepolymer (A-1), 11 parts of acetone
After charging 5 parts of N-methylvinylpyrrolidone and 35 parts of N-methylvinylpyrrolidone into a reaction vessel and dissolving them uniformly at 50°C, 14.5 parts of triethylamine was added while stirring, and 550 parts of deionized water was added while maintaining the temperature at 50°C. After stirring for 2 hours, the water extension reaction was completed.

Further, vacuum distillation was performed at 80° C. or lower to remove acetone until the distillate amounted to 115 parts to obtain 950 parts of urethane resin emulsion (a-1) with a solid content of 37%. The number average molecular weight was 32,000, and the average particle diameter was 0.1 μm.

Production example of urethane resin (A-2) 256 parts of the polybutylene adipate, 427 parts of the polycaprolactone diol, 30 parts of 1,4-cyclohexane dimetatool, 68 parts of dimethylolpropionic acid,
and 219 parts of isophorone diisocyanate (NGO10H=0.975) were charged into a polymerization container,
Heat while stirring and filling nitrogen gas, and when the temperature reaches 50°C, add 0.05 part of dibutyltin oxide.
The reaction was carried out at 0°C for 4 hours. After that, the temperature was lowered to 60°C and 50 parts of methanol was added to inactivate the unreacted NGO groups. Then, 345 parts of acetone and 105 parts of N-methyl-vinylpyrrolidone were added and stirring was continued until uniformly dissolved. A 67% urethane resin (A-2) was obtained. The number average molecular weight was 25,000.

Production side of urethane resin emulsion (a-2) Charge 528.5 parts of the urethane resin (A-2) into a reaction container,
While stirring at 50°C, 14.5 parts of triethylamine was added, and while maintaining the temperature at 50°C, 620 parts of deionized water was gradually added, and stirring was continued for an additional hour. Then 70℃
Acetone and methanol were distilled off by vacuum distillation, and the vacuum distillation was stopped when the distillate reached 139 parts.
A urethane resin emulsion (a-2) of H was obtained. The average particle diameter was 0.05 μm.

Production side molecule m2 of urethane resin emulsion (a-3)
000 polytetraoxymethylene glycol 476 parts, molecular weight 435 -FLEX188 (KING
Industries Inc., Go, cyclohexane dimetatool-terminated glue-near polyester) 1
30 parts, 1,4-cyclohexane diisocyanate 26
63 parts dimethylolpropionic acid, 3 parts glycerin.
5 parts, 184 parts of tolylene diisocyanate (TDI),
and isophorone diisocyanate) (IPDI) 117
A raw material (OH/NGO-1,33) consisting of
A urethane prepolymer containing 3.1% O groups and terminal NGO groups was obtained. Next, except for using this prepolymer, the procedure was exactly the same as emulsion (a-1), with a solid content of 38%.
A urethane resin emulsion (a-3) was obtained. The molecular weight was 43,000, and the average particle diameter was 0.07 μm.

Production Examples of Olefin Resin Emulsion (b-1) Maleated chlorinated polypropylene with an average molecular weight of ff1lo000 (chlorination rate 25%, maleic anhydride content 2.
0%), 150 parts of n-hebutane, and 50 parts of N-methylvinylpyrrolidone were charged into a reaction vessel and stirred at 70°C under a nitrogen gas atmosphere to uniformly dissolve the olefin resin solution (B-1). Obtained. Thereafter, after cooling the inside of the system to 50°C, 10.6 parts of triethylamine and Neugen EA were added.
After adding 5 parts of -140 (polyethylene glycol noniphenyl ether, nonionic surfactant, HLB14, manufactured by Dai-Kogyo Yakuhin) and stirring for 1 hour, 200 parts of deionized water
0 part was gradually added, and stirring was continued for an additional hour. Next, the solvent was removed under reduced pressure at 70°C, and n-hebutane and water were distilled off until the distillate reached 600 parts, and the solid content was 23.
A 6% olefin resin emulsion (b-1) was obtained.

The average particle size was 1.87 parts m.

Production Example of Olefin Resin Emulsion (b-2) Olefin resin solution (B -2) was obtained. 5 within the system
After cooling to 0°C, 15 parts of Neugen EA-140 (polyethylene glycol noniphenyl ether, nonionic surfactant, HLB14, manufactured by Dai-Kogyo Yakuhin) were added (
The solid content was 25.5% using exactly the same procedure as in the production example of b-1).
An olefin emulsion (b-2) was obtained. The average particle size was 2.0 μm.

Production example of acrylic resin-modified chlorinated PP emulsion (b-3) In a reaction vessel, chlorinated polypropylene resin (number average molecular ff
l (Mn) 5800, chlorine content 26%) solid content 5
700 parts of 0% toluene solution and 350 parts of butyl cellosolve
A portion was charged and heated to 100°C.

Next, a mixture of 52 parts of acrylic acid, 130 parts of styrene, 468 parts of n-butyl acrylate, 69 parts of 75% benzoyl peroxide, and 50 parts of isopropanol was added dropwise to the chlorinated polypropylene resin solution over 3 hours. , ripened at the same temperature for 1 hour, and then a solution of 3.25 parts of azobisisovaleronitrile dissolved in 50 parts of butyl cellosolve was added dropwise over 1 hour to this product, maintained at the same temperature for 1 hour, and further heated. The temperature was raised to 110°C, and unreacted monomers, water, isopropanol, and toluene were removed under reduced pressure to obtain a resin solution with a resin acid value of 40.5.

Next, while stirring the resin solution, dimethylethanolamine was added to the resin solution in an amount of 1.0 neutralization equivalent to the carboxyl group in the resin solution, and 20
75 parts added, solids content 28.2%, olefin resin/
Emulsion with acrylic resin solid content ratio = 35/65 (
b-3) was obtained. The average particle diameter was 2.0 μm.

Production side of emulsion (c-1) 208 parts of the urethane resin emulsion (a-1) and 106 parts of the olefin resin emulsion (b-1) were mixed well in a stirring vessel at 25°C, and the solid content was 31.8% ( maleic chlorinated olefin/urethane resin = 25/75)
, organic solvent content 12, (a-1) of 5PIIH,
(b-1) A mixed emulsion (c-1) was obtained.

Example of producing emulsion (c-2) 120 parts of the urethane resin (A-2) and 35 parts of the olefin resin solution (B-1) were charged into a reaction vessel, and while stirring, the inside of the thread was kept at 50°C. 3.1
1 part and Neugen EA-1400, 25 parts, and continued stirring for 1 hour. After adding 127.4 parts of deionized water over 1 hour, the solvent was removed under reduced pressure at 70°C until the distillates (acetone, methanol) were removed. Repeat until the weight is 29.6g, and the non-volatile content is 3.
9.0% (maleated chlorinated polypropylene/polyurethane ratio = 25/75), organic solvent content 17.4PI
An IR emulsion (c-2) was obtained.

The average particle diameter was 0.8 μm.

Production example of emulsion (c-3) 214.2 parts of the urethane resin emulsion (a-2) and 105 parts of the olefin resin emulsion (b-1).
9 parts were mixed well at 25°C in a stirring vessel until the solid content was 32.
(a-
2) (b-1) A mixed emulsion (c-3) was obtained.

Production example of emulsion (c-4) 262.5 parts of the urethane prepolymer (A-1), the polyolefin resin solution (B-1)
122.5 parts, N-methyl vinyl, rubirolide 726.3
and 43.8 parts of methyl ethyl ketone were charged into a reaction vessel, stirred at 70°C under a nitrogen gas atmosphere to uniformly dissolve, cooled to 50°C, added 14.5 parts of triethylamine with stirring, and dissolved at 50°C. Deionized water while keeping
0 parts was added and the mixture was stirred for 2 hours to complete the water elongation reaction.

Further, vacuum distillation was carried out below 85°C to remove heptane and methyl ethyl ketone until the distillate became 70 parts, resulting in an emulsion (c
-4) was obtained. The average particle diameter was 0.5 μm.

Production example of emulsion (c-5) 175 parts of the urethane prepolymer (A-1), 245 parts of the olefin resin solution (B-1), 17.5 parts of N-methylvinylpyrrolidone, and 43 parts of methyl ethyl ketone.
．． 8 parts of trinylamine was charged into a reaction vessel, and 11.9 parts of trinylamine was added to the reaction vessel.
The water elongation reaction was carried out in the same manner as in emulsion (c-4) except that 6 parts and 75 parts of Neugen EA-1401 were used. Heptane and methyl ethyl ketone were removed by distillation under reduced pressure, and the nonvolatile content was 36.9% (maleated Chlorinated polypropylene resin/polyurethane resin ratio=50150) A solvent-containing ft1 OPHR emulsion (c-5) was obtained. The average particle diameter was 0.9 μm.

Production example of emulsion (c-6) Maleated polyethylene-polypropylene copolymer resin (B
-3) 70 parts, N-methyl-vinylpyrrolidone 70 parts,
and 70 parts of toluene were stirred in a reaction vessel at 100° C. for 1 hour to mix well until a homogeneous solution was obtained. The temperature inside the reaction vessel was lowered to 75°C and stirring was continued, and then 280 parts of the urethane prepolymer (A-1) and 70 parts of methyl ethyl ketone were added.
After neutralizing with 14.5 parts of triethylamine, 700 parts of deionized water was added while maintaining the temperature at 75°C, and the reaction was allowed to proceed for 2 hours to complete the water extension reaction. Furthermore, methyl ethyl ketone was distilled off under reduced pressure, and the solid content was 29.3
% (maleated ethylene-propylene copolymer/polyurethane resin = 20/80), solvent content 39. 5P
An emulsion of IIR was obtained. The average particle diameter of this emulsion was 0.7 μm. This emulsion 170
．． 6 parts and the urethane resin emulsion (a-3) 1
31.5 parts were mixed to obtain an emulsion (c-6).

Production example of emulsion (c-7) 117.6 parts of the above (b-2) and 1 of the above (a-1)
Mix 89.1 parts thoroughly at 25℃ in a stirring container until the solid content is 3.
3.6% (chlorinated polypropylene resin/urethane resin ratio = 30/70), organic solvent containing ffl 14 PHR
(a-1) (b-2) mixed emulsion (c-7
) was obtained.

Example 1 Using the emulsions obtained in the above production examples, paint compositions of the present invention (paints (E-1) to (E-8)) having the following compositions and comparative paint compositions (paint (E-9)) were prepared. ) ~ (E-11))
I got it.

0 paint (E-1) 404 parts of emulsion (C-1), 100 parts of titanium white,
and 0.3 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-1).

O paint (E-2) 256 parts of emulsion (c-2), 100 parts of titanium white,
and 0.3 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-2).

O paint (E-3) 320 parts of emulsion (c-3), 100 parts of titanium white,
and 0.3 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-3).

0 paint (E-4) 272 parts of emulsion (c-4), 100 parts of titanium white,
and carbon pigment 0. Three parts were thoroughly kneaded to obtain a gray paint (E-4).

0 paint (E-5) emulsion (c-5) 135. 5 parts, urethane resin emulsion (a-3) 131.5 parts, titanium white 1
00 parts and 0.3 parts of carbon pigment were thoroughly kneaded to obtain a gray paint (E-5).

0 paint (E-6) emulsion (c-6) 302.1 parts, titanium white 100
1 part and 0.3 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-6).

O paint (E-7) 298 parts of emulsion (c-7), 100 parts of titanium white,
and 0.3 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-7).

Q paint (E-8) 177.3 parts of emulsion (b-3), emulsion (
a-1) Mix well 135.1 parts, 100 parts of titanium white, and 0.3 parts of carbon pigment to make gray paint (E-8).
I got it.

0 paint (E-9) Polyolefin resin emulsion (b-1) 423.7
100 parts of titanium white, and 0.4 part of carbon pigment were thoroughly kneaded to obtain a gray paint (E-9).

O paint (E-10) Polyoxytetramethylene glycol with an OH value of 55 [
1020.0 parts of PTG-500 manufactured by Hodogaya Chemical Industry ■ was dehydrated under reduced pressure at 1 mniHg and 100°C.
The mixture was cooled to 85°C, and 178.6 parts of tolylene diisocyanate (tolylene diisocyanate) was added thereto, followed by a reaction at 85°C for 3 hours. Next, trimethylolpropane 134 was added to this polyurethane prepolymer.
．． Acid value 2 synthesized from 0 parts and 98.0 parts of maleic anhydride
33.8, add 49.9 parts of half ester compound,
The mixture was reacted at 85° C. for 3 hours under a nitrogen stream to obtain an isocyanate-terminated prepolymer containing carboxyl groups. This prepolymer was kept at 85°C and sodium hydroxide was
．． When the mixture was poured into 1534 parts of an aqueous solution containing 2 parts using a homomixer and emulsified, a milky white solid content of 4
A 4.9% polyurethane emulsion was obtained.

222.7 parts of this emulsion, 100 parts of titanium white, and 0.3 parts of carbon pigment were thoroughly kneaded and gray paint (E-
10) was obtained.

O paint (E-11) Soflex #2582 (manufactured by Kansai Paint Co., Ltd., modified polyolefin resin lacquer type undercoat paint, gray) was diluted with Ford Cup #4 so that the viscosity at 20°C was 13 to 14 seconds. .

For paints (E-1) to (E-10), the viscosity was 500 to 600 centiboise (B-type viscometer, 2
After adjusting the temperature to 0°C), it was used for painting.

The test results of paint performance and coating film performance for paints (E-1) to (E-11) are shown in Table 1 below.

The test method is as follows.

(*1>Storability: After the paint was placed in a polyethylene airtight container and left at 40°C for one month, the presence or absence of abnormalities such as pigment sedimentation and viscosity change was examined and evaluated using the following criteria.

◎No abnormalities such as viscosity change, separation of resin and water, pigment sedimentation, etc.

Δ: Some of the above abnormalities were observed.

V2 Viscosity change of 500 centivoise (20°C).

Something that becomes G-nigel.

Ss: Significant solvent separation.

S: Significant pigment sedimentation.

SR: Significant resin sedimentation.

(*2) Organic solvent volatilization amount: 15% based on the dry film thickness of the paint
The amount of organic solvent that evaporates out of the system during μm coating and drying process is calculated per 1 ba coated area.
g).

(Zero 8) Breaking elongation rate: The isolated coating film was spray-painted to a dry film thickness of 20 μm and dried at 80°C for 40 minutes. Graph S-D type) is used, and the sample length is 20 ma.
+, the tensile speed was measured at 20+nn+/min.

(*4) Adhesiveness: Spray paint and 80℃-30
The baked and dried test plate was left in an atmosphere of 30° C.-85% R11 for 1 hour, and then the adhesion of the coating film was evaluated by touch in the same atmosphere.

◎: No abnormalities.

Δ: Slightly poor quality.

×; Defective.

Example 2 A coating film was formed on a plastic substrate using paints (E-1) to (E-il). Coating film formation and coating film performance tests were conducted in the following manner.

(I) Object to be coated Object A: Polybrobylene (TX-933, Mitsubishi Yuka) Object B: R-RIM-PU (BF-110-50
℃MR, Bayer Urethane) Coated material C: Polyester (Bexloy, DuPont)
Coated object D: ABS (Japan Test Panel) Coated object E: Polyphenylene oxide (GTX910, engineering plastic ■) Coated object F: SMC (Hitachi Chemical ■) (II) Degreasing the above-mentioned coated objects A-C, E and For F, 1°1.1-
The coating was exposed for 1 minute in an atmosphere of trichloromethane and tan vapor, and the coating material was degreased by wiping with isopropanol, and coating was carried out in the following manner.

(■) Undercoat paint 1 based on the dry coating film of the above paints (E-1) to (E-11)
Spray paint with 4kg/c [IT air pressure so that it is 5-20μm, leave it at room temperature for 30 minutes,
It was dried for 40 minutes at 0°C.

(IV) Top coat (I
Soflex #200 (manufactured by Kansai Paint Co., Ltd., polyester-urethane resin two-component solvent-based paint, white) was spray-painted with an air pressure of 4 kg/cJ to a thickness of 30 to 40 μm based on the dry film, and then left at room temperature. So 3
After setting for 0 minutes, forced drying was performed at 80° C. for 40 minutes. Table 2 shows the performance evaluation of the obtained test plates.

Apply Soflex #1400 Silver (manufactured by Kansai Paint Co., Ltd., aminopolyester resin solvent-based paint) as a top coat (b) to the painted surface on which a film was formed in (■) so that the thickness becomes 15 to 20 μm based on the dry film. spray painted on,
Next, after leaving it at room temperature for 3 minutes, apply Soflex #16.
00 Clear (manufactured by Kansai Paint Co., Ltd., trade name, aminoacrylic resin solvent-based paint) was spray-painted to a dry film thickness of 30 to 35 μm, left at room temperature for 20 minutes, and then
It was dried at ℃ for 40 minutes and used for the test. The results are shown in Table 3.

Similarly, on the coated surface where a film was formed in (■), the water-based metallic paint shown below was applied as a top coat (c) to a thickness of 15 to 20 μm based on the dry film thickness, and then a wet-on-wet solvent-based clear was applied. The paint was applied to a dry film thickness of 35 to 40 μm, and then baked at 140° C. for 20 minutes.

Table 4 shows the performance of the coated plates.

The top coat (c) was manufactured as follows.

(c)-1 Water-soluble paint for metallic base coat (A) Methyl methacrylate/styrene/acrylic acid n-
Average obtained by emulsion polymerization of a monomer mixture consisting of butyl/acrylic acid/2-hydroxyethyl acrylate/2-ethylhexyl acrylate (OH group concentration 0.63 mmol/g, COOH group concentration 0.15 mmol/g) 175 parts of an acrylic resin emulsion with a particle diameter of 0.1 μm and a solid content of 20%, (B) Polybutylene adipate with a number average molecular weight of 12,000/polycaprolactone diol with a number average molecular weight of 12,000/dimethylolpropionic acid/1°4-butanediol/ 71.4 parts of a urethane resin emulsion with a solid content of 42.0% obtained by water extension reaction of a urethane prepolymer composed of isophorone diisocyanate, (C) Acrysol ASE-60 (manufactured by Rohm & Suha, Inc.) adhesive) 3 parts, (D) Cymel 325 (Mitsui Toatsu Chemical ■, water-soluble melamine resin) 31 parts, and (E) aluminum paste (total metal content 65%) 23
3000 centipoise (Type B viscometer) water-based paint for metallic base coats diluted with deionized water.

(c)-2 Clear paint An acrylic resin quijiro solution with an acid value of 12 and a hydroxyl value of 58 and a resin solid content of 60% obtained by copolymerizing methyl acrylate/ethyl acrylate/n-butyl acrylate/2-hydroxyethyl acrylate/acrylic acid. 125
and 41.7 parts of Kneepan 20SE (manufactured by Mitsui Toatsu Chemical ■, melamine resin) were mixed, diluted with Swasol 1500 (organic solvent, manufactured by Maruzen Petrochemical ■), and mixed with Ford Cup #
Clear paint adjusted to a viscosity of 25 seconds at 4 (20℃).

Test method (*5) Painted surface appearance: - Painted surface gloss...JIS K-540019796,
Measured according to 7. (reflectance 60 degrees)・Painted surface smoothness・
...The smoothness of the painted surface was visually evaluated, and the smoothness of the coated surface was evaluated as ◎ if it was good, × if it was bad, or Δ if it was between ◎ and ×.

・Painted surface abnormalities: Visually evaluate the defects such as bumps, dents, underarms, etc.
The presence or absence of sauce was checked, and those with no abnormality were marked ◎.

(*6) Adhesiveness: JIS K5400-19796.
A rough pattern was made on the coating film according to No. 15, an adhesive cellophane tape was attached to the surface, and the coated surface was evaluated after it was rapidly peeled off.

The evaluation was expressed as the number of gobbles that did not peel off against the total number of gobbles (100).

(*7) Water resistance: Immediately after being immersed in water at 40°C for 10 days, the coated surface was evaluated by the coated surface gloss according to (*5) and the adhesion test according to (*6).

(*8) Flexibility: Cut a test plate into a size of 20 x 150 mm and wrap it around a cylinder (made of steel) with a diameter of 25.4 mm in an atmosphere of 20°C or -20°C with the painted side facing outside. , and 180' bending, and evaluated on a scale of ◎ to × based on the degree of peeling, cracking, etc. of the coating film. ◎: No abnormality at all, ○: slight cracks are observed, Δ: cracks are observed, X: cracks and peeling are observed.

Claims (2)

[Claims] (1) A water-based coating composition for plastic substrates, characterized in that the vehicle component is an aqueous version of an olefin resin and a urethane resin. (2) A method for forming a coating film, which comprises applying the coating composition according to claim 1 to a plastic substrate, drying the coating composition, and then applying a top coating composition and drying the coating composition.