JP5378937B2 - Conductive water-based primer composition and primer coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive water-based primer composition with which a coating film capable of covering either of a substrate surface formed by using an ABS resin as a main component and a substrate surface formed by using a PPE resin as a main component with an excellent adhesion property is formed, and to provide a primer coating film. <P>SOLUTION: The conductive water-based primer composition includes: an aqueous styrene-(meth)acrylic copolymer (A); a modified polyolefin resin (B); and a conductive material (C), and the primer coating film is formed of the primer composition. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a conductive water-based primer composition and a primer coating, and more specifically, any of the surface of a substrate formed mainly of ABS resin and the surface of a substrate formed mainly of polyphenylene ether resin. TECHNICAL FIELD The present invention relates to a conductive aqueous primer composition capable of forming a coating film that can be coated with good adhesion on a substrate surface, and a primer coating film that can coat any of the substrate surfaces with good adhesion. .

  Plastic substrates are used in various fields because they are easy to process and handle. As a method of coloring such a plastic substrate, for example, a method of coloring by coloring a colorant such as a dye or a pigment into the plastic substrate itself is employed, but there is a limit to the degree of color development. In fields where high gloss and high design properties such as glitter are required, coloring by painting is mainly employed. Various resins are used as a binder of a paint to be applied to a plastic substrate depending on the type of the substrate.

  Until now, organic solvent-based paints have often been used. However, in recent years, environmental problems related to organic solvents have been highlighted, and water-based paints are strongly desired. Under such a background, a paint using an aqueous dispersion of various binder resins has been studied as a paint to be applied to a plastic substrate. Among these, several techniques relating to an aqueous coating composition for undercoating a plastic substrate are known (for example, Patent Documents 1 and 2).

  The problem of the invention disclosed in Patent Document 1 is “A melamine-curable aqueous solution that exhibits excellent adhesion to both the coating film and the low-polarity plastic substrate and is stable even after long-term storage. It is to provide a coating composition "(see paragraph No. 0013 of Patent Document 1).

  Means for achieving the object of the invention described in Patent Document 1 are based on a polyester resin (A) having a specific acid value, hydroxyl value and number average molecular weight, melamine resin (B), and resin solid content. And an aqueous coating composition for a plastic substrate containing an alkylbenzenesulfonic acid or alkylsulfuric acid (C) having a specific molecular structure and an aqueous medium in specific parts by weight (for details, refer to claim 1 of Patent Document 1). about).

  According to the description in paragraph No. 0037 of Patent Document 1, the base material that is the object to be coated with the melamine-curable aqueous coating composition according to the invention described in Patent Document 1 is an engineering plastic material, and the engineering plastic material "Nonyl GTX (trade name) (manufactured by GE Plastics, Inc.)", "Artly (trade name)" (manufactured by Sumitomo Chemical Co., Ltd.), "Zylon (trade name)" (manufactured by Asahi Kasei Corporation), “Remalloy (trade name)” (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) is exemplified by the trade name, and it is not always clear what kind of material the object is formed from.

  “Nonyl GTX” manufactured by Nippon GE Plastics Co., Ltd. does not seem to have such a product until now, but Japan GE Plastics Co., Ltd. sells “Noryl GTX”. “Noryl GTX” is NORYL GTX (trade name) and is considered to be a polymer alloy of polyamide resin and modified polyphenylene ether resin (PPE) (see paragraph No. 0004 of JP-A-2007-69622). “Artly (trade name)” is a high-performance engineering plastic alloy in which PPE (amorphous engineering plastic) and nylon (crystalline engineering plastic) are alloyed by Sumitomo Chemical Co., Ltd. using a unique alloying material (http : //www.sumitomo-chem.co.jp/polyolefin/03product/16artley.html). “Zylon (trade name)” is a polymer alloy of polyphenylene ether (PPE) and polystyrene (http://www.akchem.com/emt/contentsfiles/xyron/whats_xyron.pdf). “Remalloy (trade name)” is a polymer alloy having a sea-island structure in which polyphenylene ether resin (PPE) is used as an island and crystalline resins such as polyamide resin, polyester resin, and polypropylene resin are arranged in the sea (http: //www.m-ep.co.jp/mep-j/products/lemalloy/index.htm).

  The article to be coated on which the coating film is formed with the water-based paint composition for a plastic substrate described in Patent Document 1 is commonly a polymer alloy containing a polyphenylene ether resin (PPE).

The subject of the invention described in Patent Document 2 is, as described in paragraph 0007, “excellent adhesion to plastic substrates such as ABS and nylon, adhesion to top coat film, and water resistance. Another object of the present invention is to provide an aqueous primer composition that can form an electrically conductive primer coating.
As means for solving the above-mentioned problems of the invention described in Patent Document 2, claim 1 is “
(A) an aqueous dispersion of a modified polyolefin obtained by dispersing a polyolefin (a) modified with an unsaturated carboxylic acid or acid anhydride in an aqueous medium,
An aqueous primer composition containing (B) an acrylic resin and (C) a conductive pigment,
The acrylic resin (B) emulsifies a monomer mixture containing 55 to 90% by weight of methyl (meth) acrylate, 10 to 30% by weight of ethyl (meth) acrylate, and 1 to 30% by weight of other copolymerizable unsaturated monomers. An aqueous primer composition characterized in that it is an acrylic emulsion obtained by polymerization, and the solid content weight ratio of the component (A) / component (B) is in the range of 50/50 to 85/15 ". is there.

  In addition, as an invention described in Patent Document 2, the claim 4 is “a carboxylic acid base having a tertiary amino group, a quaternary ammonium base, a sulfonic acid group, a phosphoric acid group, and a quaternary ammonium salt as a counter ion. The aqueous primer composition according to claim 1, further comprising an acrylic resin (D) having at least one ionic functional group selected from:

  According to the description in paragraph No. 0009 of Patent Document 2, “According to the present invention, by blending an aqueous dispersion of a modified polyolefin and an acrylic emulsion having a specific monomer composition in a specific ratio, a plastic substrate such as ABS or nylon can be obtained. It is possible to form an electrically conductive primer coating that is excellent in adhesion, adhesion to the top coat, water resistance, etc. "

  According to the description in paragraph No. 0037 of Patent Document 2, “In the present invention, the weight ratio of the solid component (A) / component (B) is 50/50 from the viewpoint of adhesion of the formed coating film, water resistance, etc. -85/15, preferably in the range of 60/40 to 80/20, if it is out of this range, the adhesion of the resulting coating film to a plastic substrate such as ABS or nylon is not preferred. "

Referring to the example of Patent Document 2,
In Example 1, an aqueous polypropylene / ethylene copolymer (A-1) modified with a maleic acid addition amount of 8% by weight, an acrylic emulsion (B-1), and an ionic functional group-containing resin (D-2) An aqueous primer (1) comprising
In Example 2, an aqueous primer containing 50 parts by weight of an aqueous polypropylene / ethylene copolymer (A-1), an acrylic emulsion (B-2), and an ionic functional group-containing resin (D-2) solution. (2) was demonstrated,
Example 3 demonstrates an aqueous primer (3) containing an aqueous polypropylene / ethylene copolymer (A-1), an acrylic emulsion (B-1), an ionic functional group-containing resin (D-1),
In Example 4, an aqueous chlorinated polypropylene / ethylene copolymer (A-2) modified with a maleic anhydride addition amount of 2% by weight and a chlorine content of 20%, an acrylic emulsion (B-1), an ionic functional group An aqueous primer (4) containing the containing resin (D-2) was demonstrated,
In Example 5, an aqueous primer (5) containing an aqueous chlorinated polypropylene / ethylene copolymer (A-2), an acrylic emulsion (B-2), and an ionic functional group-containing resin (D-2) solution was demonstrated. And
Example 6 demonstrates an aqueous primer (6) containing an aqueous dispersion of modified polypropylene (A-3), an acrylic emulsion (B-2), and an ionic functional group-containing resin (D-2) solution. .

  In Patent Document 2, an aqueous dispersion (A) of a modified polyolefin, an acrylic resin (B), a conductive pigment (C), and an acrylic resin (D) having an ionic functional group as defined in claim 4 are provided. It has been shown that the water-based primer composition contained in a specific blending ratio is excellent in adhesion to plastic substrates such as ABS and nylon, adhesion to the top coat film, water resistance, etc. The aqueous primer composition containing the modified polyolefin aqueous dispersion (A), the acrylic resin (B), and the conductive pigment (C) in a specific blending ratio as defined in Item 1 The embodiment does not show that

  Nevertheless, the invention according to claim 1 shown in Patent Document 2 is an aqueous dispersion (A) of a modified polyolefin and an acrylic resin, which is a means by which technical effects cannot be confirmed by the examples. It is an aqueous primer composition containing (B) and a conductive pigment (C) at a specific blending ratio. Means in which the technical effect cannot be confirmed is merely a desire, and an invention having a means in which the technical effect cannot be confirmed is an incomplete invention.

  Therefore, the invention disclosed and completed in Patent Document 2 is the invention according to Claim 4, which is an aqueous dispersion (A) of modified polyolefin, an acrylic resin (B), and a conductive pigment (C). And an acrylic resin (D) having an ionic functional group at a specific blending ratio. In other words, the invention according to claim 1 disclosed in Patent Document 2 cannot be handled as the prior art.

  In addition, in Claim 1 described in patent document 2, the polyolefin (a) (component (A)) modified with unsaturated carboxylic acid or acid anhydride and (B) acrylic resin component ( The solid content weight ratio of A) / component (B) is in the range of 50/50 to 85/15.

  Even if the invention according to claim 1 described in Patent Document 2 is an completed invention, the problem of the invention according to claim 1 is not made until the content of (B) acrylic resin is less than half of (A) polyolefin. It has been resolved.

JP 2004-292577 A JP 2008-201882 A

  By the way, as a characteristic required for the primer composition, it is possible to form a coating film having great adhesion to the material of the substrate to which the primer composition is applied, and a coating film formed with the primer composition. In addition, there is a requirement that the adhesion with the coating film to be applied can be increased. The primer composition described in the said patent documents 1 and 2 is a composition which pursues the said requirements.

  However, the primer composition that tries to satisfy the requirements cannot satisfy the requirements for other specific substrates even if the requirements for the specific substrate are satisfied. It is. Therefore, for each material of the base material, the composition of the primer composition has to be studied so that a coating film can be formed on the base material surface with good adhesion.

  The problem to be solved by the present invention is that a base material made of an engineering plastic containing ABS resin as a main component and a base material made of an engineering plastic containing a PPE resin having a completely different molecular structure from the ABS resin. High adhesion to any base material composed of materials with different molecular structures and properties such as conductive water-based primer composition and ABS resin and PPE resin that can form a primer coating with good adhesion. It is in providing the primer coating film which adheres by.

As means for solving the problems,
(1) (A) containing an aqueous styrenated (meth) acrylic copolymer, (B) a modified polyolefin resin and (C) a conductive material ,
The (A) aqueous styrenated (meth) acrylic copolymer and the (B) modified polyolefin resin are in a mass ratio of 8: 2 to 5.5: 4.5,
The modified polyolefin resin is a conductive aqueous primer composition characterized by containing a non-chlorine maleic acid-modified polyolefin resin ,
(2) A primer coating film formed from the conductive aqueous primer composition according to (1) ,
(3) In the above (2) , the critical surface tension γc _substrate of the substrate surface and the surface tension γ _{film of the} primer coating film formed on the substrate surface satisfy the following relational expression: It is a primer coating film of description.
Critical surface tension of _substrate surface γc _substrate ≧ surface tension of primer coating γ _film

  According to the present invention, adhesion to both a base material made of an engineering plastic mainly composed of ABS resin and a base material made of an engineering plastic containing a PPE resin having a molecular structure completely different from the ABS resin. It is possible to provide a conductive water-based primer composition that can form a primer coating well, and a primer coating.

  The conductive aqueous primer composition according to the present invention contains (A) an aqueous styrenated (meth) acrylic copolymer, (B) a modified polyolefin resin, and (C) a conductive material.

  The (A) aqueous styrene (meth) acrylic copolymer emulsion-polymerizes a styrene monomer and one or more copolymerizable α, β-ethylenically unsaturated monomers in water. The aqueous dispersion and / or the styrenic monomer and the ethylenically unsaturated monomer having at least one carboxyl group in one molecule as essential components, and other copolymerizable one or two An aqueous dispersion obtained by copolymerizing one or more kinds of α, β-ethylenically unsaturated monomers, neutralizing with a neutralizing agent, and adding water. In the conductive aqueous primer composition according to the present invention, the (A) aqueous styrenated (meth) acrylic copolymer can be used in the form of an aqueous dispersion. The (A) aqueous styrenated (meth) acrylic copolymer usually has an acid value of preferably 5 to 100 mgKOH / g, and the aqueous styrenated (meth) acrylic copolymer preferably has a glass transition temperature of 8 to 100 ° C.

  Typical examples of the polymerization method include an ethylenically unsaturated monomer containing a styrene monomer in water in the presence of an emulsifier and a polymerization initiator, and if necessary, a chain transfer agent and an emulsion stabilizer. In general, emulsion polymerization is carried out under heating at 60 to 90 ° C., and in some cases, this step is repeated in a plurality of stages, and in the presence of a polymerization initiator in an organic solvent and, if necessary, a chain transfer agent. After copolymerizing a styrene monomer, an ethylenically unsaturated monomer having a carboxyl group and a copolymerizable ethylenically unsaturated monomer, usually under heating at 60 to 130 ° C., water and neutralization There is a method of adding an agent and optionally adding an emulsifier to carry out phase conversion.

  Examples of the emulsifier in the emulsion polymerization method and the phase conversion method include fatty acid salts such as sodium lauryl sulfate, alkylbenzene sulfonates such as higher alcohol sulfate esters and sodium dodecylbenzenesulfonate, polyoxyethylene alkyl ether sulfates, Polyoxynonyl phenyl ether ammonium sulfonate, polyoxyethylene-polyoxypropylene glycol ether sulfate, sulfonic acid group or sulfate group and polymerizable carbon-carbon unsaturated double bond in the molecule, so-called reactivity Anionic surfactants such as emulsifiers; polyoxyethylene alkyl ether, polyoxyethylene nonylphenyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene-polyoxy Nonionic surfactants such as propylene block copolymers or reactive nonionic surfactants having a skeleton and a polymerizable carbon-carbon unsaturated double bond in the molecule; alkylamine salts and quaternary ammonium salts Cationic surfactants such as: (modified) polyvinyl alcohol and the like.

  As the polymerization initiator, those conventionally used for radical polymerization can be used, but water-soluble ones are preferred, for example, persulfates such as potassium persulfate and ammonium persulfate. 2,2′-azobis (2-aminodipropane) hydrochloride, 4,4′-azobis-cyanovaleric acid, 2,2′-azobis (2-methylbutanamidooxime) dihydrochloride tetrahydrate And peroxides such as hydrogen peroxide and t-butyl hydroperoxide. Furthermore, a redox system in which a reducing agent such as L-ascorbic acid or sodium thiosulfate is combined with ferrous sulfate or the like can also be used.

  Examples of the chain transfer agent include alkyl mercaptans such as lauryl mercaptan, n-butyl mercaptan, t-butyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, thioglycolic acid-2-ethylhexyl, 2-methyl-t-butyl. Examples thereof include thiophenol, carbon tetrabromide, and α-methylstyrene dimer. By appropriately using these, the gloss, film formability, and non-adhesiveness of the coating film can be controlled.

  Examples of the emulsion stabilizer include polyvinyl alcohol, hydroxyethyl cellulose, and polyvinyl pyrrolidone.

  Further, the emulsion polymerization method includes a monomer batch charging method in which monomers are charged in a batch, a monomer dropping method in which monomers are continuously dropped, and a monomer is mixed and emulsified in advance with water and an emulsifier. In addition, a pre-emulsion method in which this is dropped, or a method in which these are combined is exemplified.

  Examples of the styrene monomer that is an essential component include styrene, methylstyrene, chlorostyrene, and methoxystyrene.

  In addition, as the α, β-ethylenically unsaturated monomer copolymerizable with the styrenic monomer, various ethylenically unsaturated monomers conventionally used in the production of acrylic resins are not particularly limited. Can be used.

  Specifically, for example, methyl (meth) acrylate, ether (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, α-chloroethyl (meth) acrylate, phenyl (meth) acrylate, (Meth) acrylate monomers such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate; 2-hydro Hydroxyl-containing monomers such as ciethyl (meth) acrylate, 2 (3) -hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, mono (meth) acrylic acid ester of allyl alcohol polyhydric alcohol; 2-aminoethyl Amino group-containing monomers such as (meth) acrylate, dimethylaminoethyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 2-butylaminoethyl (meth) acrylate, vinylpyridine; acrolein, diacetone (meta ) Acrylamide, formysterol, (meth) acryloxyalkylpropanal, diacetone (meth) acrylate, acetonyl (meth) acrylate, acetoacetoxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate And carbonyl group-containing ethylenically unsaturated monomers such as butanediol-1,4-acrylate-acetylacrylate, vinyl ethyl ketone and vinyl isobutyl ketone.

  Examples of the ethylenically unsaturated monomer containing a carboxyl group include (meth) acrylic acid, crotonic acid, itaconic acid, itaconic acid half ester, maleic acid, maleic acid half ester, and the like.

  In the present invention, the carboxyl group-containing ethylenically unsaturated monomer can be used without any particular limitation, but is preferably used in an acid value range of 5 mgKOH / g to 100 mgKOH / g. If it is less than 5 mg KOH / g, the mechanical stability of the aqueous dispersion and the stability during storage are lowered, and aggregation and precipitation may occur, which is not preferable. On the other hand, if it exceeds 100 mgKOH / g, the water resistance is not preferred.

  Furthermore, divinylbenzene, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, etc., which are monomers having two or more polymerizable unsaturated double bonds in the molecule. The method used; combining monomers having functional groups that react with each other at temperature during the polymerization reaction, for example, ethylenic polymers having a functional group such as a carboxyl group and a glycidyl group, or a hydroxyl group and an isocyanate group. A method using a monomer mixture containing a saturated monomer selectively; hydrolyzable silyl group such as (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropylmethyldimethoxysilane, etc., which undergoes a hydrolytic condensation reaction A monomer mixture containing the containing ethylenically unsaturated monomer can be used.

  In the present invention, the styrenic monomer and the copolymerizable monomer can be used without particular limitation, but the glass transition temperature (hereinafter referred to as Tg) of the aqueous styrenated (meth) acrylic copolymer is It is preferable to combine so that it may become 8 to 100 degreeC. If it is less than 8 degreeC, since the adhesiveness of the coating-film surface will express, it is unpreferable. On the other hand, if the temperature exceeds 100 ° C., it is not preferable because a large amount of film-forming auxiliary is required for following the substrate and forming the film.

  In the present invention, the Tg of the aqueous styrenated (meth) acrylic copolymer is calculated using the following FOX equation.

1 / Tg = W ₁ / Tg ₁ + W ₂ / Tg ₂ +... + W _i / Tg _i +... + W _n / Tg _n
[In the FOX formula, the glass transition temperature of the homopolymer of each monomer constituting the polymer composed of n types of monomers is Tg _i (K), and the mass fraction of each monomer is W _i , (W ₁ + W ₂ +... + W _i +... + W _n = 1)]

  Examples of the organic solvent used in the phase conversion method include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and benzyl alcohol; methyl ethyl ketone, acetone, methyl isobutyl ketone, methyl isoamyl ketone, diacetone alcohol, Ketones such as cyclohexane; ether alcohols such as 2-butoxyethanol, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethyl ether and butyl diglycol; esters of ethyl acetate; toluene, xylene, etc. And aromatic hydrocarbons.

  The aqueous styrenated (meth) acrylic copolymer thus obtained is preferably neutralized by adding a neutralizing agent. Typical examples of the neutralizing agent include triethylamine, triethanolamine, dimethylethanolamine, monoethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, morpholine, ammonia and the like. In addition, the amount of water added after neutralization by the phase change method, or the amount of water added together with the neutralizing agent is added in consideration of the coating workability of the paint, etc., but usually the aqueous styrene (meth) acrylic copolymer An amount such that the solid content ratio of the dispersion is 10 to 70% by mass is appropriate. In addition, since a large amount of volatile organic components are contained after phase conversion, the organic solvent may be removed under reduced pressure according to a conventional method.

  (B) The modified polyolefin resin can be used in the form of an emulsion containing the modified polyolefin resin.

  Examples of the modified polyolefin resin used in the present invention include chlorinated polypropylene resin, acrylic-modified chlorinated polypropylene resin, maleic anhydride-modified polypropylene resin, non-chlorinated maleic acid-modified polyolefin resin, and the like. May be used.

  Other polyolefin resins include various polyethylenes such as low density, ultra low density, high density, isotactic or syndiotactic polypropylene, propylene / ethylene block or random copolymer, polybutene-1, poly-3-methyl-1-butene , Poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, cycloolefins and the like.

  A suitable modified polyolefin resin is obtained by modifying the polyolefin resin with an unsaturated carboxylic acid or acid anhydride. Examples of the unsaturated carboxylic acid may include monovalent unsaturated fatty acids such as linoleic acid, linolenic acid, and oleic acid. Suitable unsaturated carboxylic acids include unsaturated dicarboxylic acids such as maleic acid and fumaric acid, Examples thereof include unsaturated tricarboxylic acids such as aconitic acid. Examples of the acid anhydride include acetic anhydride, propionic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, etc. Among these, maleic anhydride is preferable. In the polyolefin resin modified with maleic anhydride, the maleation degree is preferably 1 to 5%. In this case, the maleation degree can be measured by the acid value.

  A suitable emulsion of a polyolefin resin such as polypropylene modified with an acid anhydride has a solid content of 20 to 40% and a viscosity of 5 to 50 mPs / 25 ° C. The modified polyolefin resin contained in the emulsion usually has an average molecular weight of 50,000 to 70,000 and a melting point of usually 60 to 150 ° C., particularly preferably 60 to 70 ° C.

  The modified polyolefin resin in this invention may be a modified polyolefin containing chlorine, but it is preferable not to contain a chlorine-modified polyolefin resin so as not to lower the strength of the primer coating film. Furthermore, the (B) modified polyolefin resin emulsion is preferably an emulsion containing a non-chlorine modified polyolefin resin, and an emulsion containing a non-chlorine maleic acid modified polyolefin resin is particularly preferred. Examples of the non-chlorine maleic acid-modified polyolefin resin include polyolefin resins that do not contain chlorine in the molecule and are modified with maleic acid or maleic anhydride, particularly polypropylene resins.

  In this invention, the weight ratio of the solid content of (A) the aqueous styrenated (meth) acrylic copolymer and (B) the modified polyolefin resin is preferably 8: 2 to 5.5: 4.5, particularly 7.5: 2. .5-6: 4 are preferred. When the ratio is outside the above range, particularly when the ratio of (A) the aqueous styrenated acrylic copolymer is small, the primer composition formed of such a conductive aqueous primer composition is an engineering plastic mainly composed of ABS resin. The adhesiveness with respect to either the base material formed in (1), the base material formed from the engineering plastic containing PPE resin, or both shows the tendency to fall.

  The conductive material (C) in this invention is not particularly limited as long as it can impart conductivity to the coating film to be formed, and any of particles, flakes, and fibers (including whiskers) can be used. It may be a shape. Specific examples of the conductive agent (C) used include conductive carbon such as conductive carbon black, carbon nanotube, carbon nanofiber, and carbon microcoil, and metal powder such as silver, nickel, copper, graphite, and aluminum. Furthermore, tin oxide doped with antimony, tin oxide doped with phosphorus, acicular titanium oxide surface coated with tin oxide / antimony, conductive titanium oxide, antimony oxide, zinc antimonate, indium Tin oxide, carbon or graphite whisker surface coated with tin oxide, flaky mica surface tin oxide, antimony-doped tin oxide, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), phosphorus-doped oxidation Conductive metal oxides such as tin and nickel oxide Coated pigments, such as pigments having conductivity comprising tin oxide and phosphorus in the titanium dioxide particle surface and the like. In addition, a pearl luster pigment doped with metal or conductive barium sulfate can also be used as a conductive material. These can be used alone or in combination of two or more. Of these, conductive carbon is particularly preferred. (C) As content of electroconductive material, 4-10 mass parts is with respect to 100 mass parts of total resin solid content of (A) aqueous styrenated (meth) acrylic copolymer and (B) modified polyolefin resin. Preferably, 5-9 mass parts is more preferable. When the content is less than 4, the conductivity is lowered, which is not preferable. When the content exceeds 10 parts by mass, the adhesion with the substrate tends to be lowered.

  Examples of pigments that can be contained in the conductive water-based primer composition according to the present invention include titanium oxide, bengara, aluminum paste, azo-based, phthalocyanine-based colored pigments, talc, silica, calcium carbonate, barium sulfate, zinc white ( Extender pigments such as zinc oxide), which can be used alone or in combination of two or more.

  In addition, various additives usually used for water-based paints such as an antioxidant, an antifoaming agent, a wax, an antiseptic, a rheology control agent, and a surface conditioner can be blended as necessary.

The surface tension γ _film of the coating film of the conductive aqueous primer composition according to the present invention and the critical surface tension γc _{substrate of the} substrate surface are preferably represented by the following relational expression.

Critical surface tension of _substrate surface γc _substrate ≧ surface tension of primer coating γ _film
Here, the critical surface tension γc refers to the surface tension value of a liquid that can completely wet the substrate. The lower the γc, the lower the surface energy of the solid surface. The critical surface tension is described in WAZizman, J. Paint Technol., 44 (564), 41 (1972).

  When the surface tension of the primer coating film is larger than the critical surface tension of the substrate surface, the adhesion of the primer coating film to the substrate may be lowered.

  Examples of the base material to which the conductive aqueous primer composition is applied include a base material mainly composed of ABS resin and a base material mainly composed of PPE resin. However, the conductive aqueous primer composition according to the present invention can be applied to a substrate other than the substrate to form a primer coating film.

  The conductive water-based primer composition can be applied using, for example, air spray, airless spray, rotary atomization coating, dip coating, or brush.

  A primer coating film is formed by drying or curing the conductive aqueous primer composition coated on the surface of the substrate.

  As a method for drying or curing the conductive aqueous primer composition, for example, room temperature drying, baking drying, and the like can be used, and these methods include a specific composition of the conductive aqueous primer composition and It can select suitably according to the material etc. of a base material. The drying conditions are also appropriately selected according to the specific composition of the conductive aqueous primer composition, the type of the substrate, and the like. Moreover, the thickness of a primer coating film has a dry film thickness, for example, the range of 5-15 micrometers is preferable. If it is thinner than 5 μm, it may be a primer coating film having poor appearance and adhesion, and if it is thicker than 15 μm, it may be a primer coating film having poor water resistance and moisture resistance.

The primer coating film formed using the conductive aqueous primer composition according to the present invention can coat the specific substrate surface with good adhesion. The primer coating film has a critical surface tension γc _substrate on the surface of the _substrate and a surface tension γ _{film of the} primer coating film formed on the surface of the substrate.
Critical surface tension of _substrate surface γc _substrate ≧ surface tension of primer coating γ _film
When it is a case where it satisfy | fills, the primer coating film which exhibits the bigger adhesiveness with respect to a base material is formed.

  The primer coating film according to the present invention may have a coating film on its surface by applying a coating as necessary. The paint can be applied regardless of whether it is solvent-based, solvent-free, or water-based, and the color pigment blended may be organic or inorganic.

(Examples and Comparative Examples)
<Preparation of aqueous styrenated (meth) acrylic copolymer>
100 parts of ethylene glycol monobutyl ether was added to a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a dripping device, and heated to 100 ° C. while stirring. Next, a mixture of 50 parts of styrene, 25 parts of isobutyl methacrylate, 18.5 parts of butyl acrylate, 6.5 parts of acrylic acid, and 1 part of t-butylperoxy-2-ethylhexanoate (polymerization initiator) was added at 100 ° C. The mixture was continuously added dropwise over 3 hours, then heated to 105 ° C., maintained for 2 hours, and the reaction was terminated. Subsequently, 100 parts of ion-exchanged water and 8 parts of N, N-dimethylethanolamine were added, and then the solvent was removed under reduced pressure (1.3 × 10 ⁴ Pa (100 torr)). N-dimethylethanolamine was added to adjust the dilution so that the solid concentration was 40% by mass and pH 7.5, and (A) an aqueous styrenated (meth) acrylic copolymer having an acid value of 50 mg KOH / g and Tg of 46 ° C. Obtained.

<Preparation of conductive aqueous primer composition>
Aurolen AE-201 (solid content concentration of 30) containing 16% by mass of (A) aqueous styrenated (meth) acrylic copolymer obtained above and (B) 9.1% by mass of non-chlorinated maleic acid-modified polyolefin. The conductive water-based primer composition having the composition shown in Table 1 is blended so that the solid content ratio (A / B) shown in Table 1 is 7/3. (7/3) was prepared. The blending amount unit in Table 1 is part by mass.

  (A) solid content mass ratio of aqueous styrenated (meth) acrylic copolymer and (B) non-chlorine maleic acid modified polyolefin resin is 10/0, 8/2, 6/4, 4.5 / 5.5, A conductive aqueous primer composition having the same composition as that of the conductive aqueous primer composition (7/3) was obtained except that 3/7 and 0/10 were used. The obtained composition was made into conductive aqueous primer composition (10/0), conductive aqueous primer composition (8/2), conductive aqueous primer composition (6/4), conductive aqueous primer composition (4.5 /5.5), conductive aqueous primer composition (3/7), conductive aqueous primer composition (0/10).

<Creation of test paint plate>
A conductive water-based primer composition was applied to various substrate surfaces described later by air spray so that the dry coating film became about 10 μm, and forcedly dried at 70 ° C. for 3 minutes.

<Method of measuring surface tension of conductive water-based primer coating film and measurement results>
The conductive aqueous primer composition was coated on a polypropylene plate at 5 to 15 μm, baked and dried at 70 ° C. for 30 minutes, and the dried coating film was peeled off from the polypropylene plate to obtain a primer coating film. Liquid paraffin and glycerin were dropped onto the primer primer back surface (the surface that was in contact with the polypropylene plate), and the contact angle with the coating film was measured with a contact angle meter (DM500, manufactured by Kyowa Interface Science Co., Ltd.). The surface tension was calculated from the Owens equation and the Young equation.

γ _L (1 + cos θ _L ) = 2 (γ _S ^d × γ _L ^d ) ^1/2 +2 (γ _S ^p × γ _L ^p ) ^1/2
γ _film = γ _S ^d + γ _S ^p
However, γ _L is the surface tension of the liquid (liquid paraffin or glycerin)
γ _S ^d is a solid surface tension dispersion component,
γ _L ^d is a liquid surface tension dispersion component,
γ _S ^p is a solid surface tension polar component,
γ _L ^p is the surface tension polarity of the liquid,
γ _S is the surface tension.

In addition, γ _L , γ _L ^d and γ _L ^p of liquid paraffin are 38.1 mN / m, 38.1 mN / m and 0 mN / m, respectively, and γ _L , γ _L ^d and γ _L ^p of glycerin are 63.4 mN / m, 37.0 mN / m and 26.4 mN / m, respectively.

The primer coating film was peeled off from the substrate, and the surface tension γ _film on the substrate side surface of the primer coating _film was measured.

<Measurement method and measurement result of critical surface tension measurement of substrate>
As shown in Table 3, four types of ABS resin substrates A to D having different critical surface tensions and two types of PPE resin substrates having different critical surface tensions were used.

  The critical surface tension of these substrates was measured as follows.

The contact angle values for each substrate were measured using four types of liquids with known surface tension, liquid paraffin, formamide, glycerin and distilled water. The horizontal axis represents the surface tension value of each liquid, and the vertical axis represents the surface tension value. The surface tension value when cos θ = 1 was calculated as a Zisman plot with cos θ taken as the critical surface tension γc _{substrate of the substrate} .

ABS resin base material A to D: UMG ABS (trade name, manufactured by UMG ABS Co., Ltd.)
PPE resin base material A, B: Zylon (trade name, manufactured by Asahi Kasei Chemicals Corporation)
<Adhesion test method>
In the adhesion test (JIS-K5400 8.5.2 grid pattern tape method), 100 grids are formed on each test coating plate so that each side has a grid pattern of 2 mm, and on the grid pattern. This is a method of sticking an adhesive tape, then peeling the adhesive tape, and evaluating the adhesion based on the number of grids remaining attached. In the present invention, the following evaluation was made.
○: 95 to 100 pieces Δ: 50 to 94 pieces ×: 49 pieces or less Table 4 shows the adhesion test results.
<Adhesion test results>

Claims (3)

(A) an aqueous styrenated (meth) acrylic copolymer, (B) a modified polyolefin resin and (C) a conductive material ,
The (A) aqueous styrenated (meth) acrylic copolymer and the (B) modified polyolefin resin are in a mass ratio of 8: 2 to 5.5: 4.5,
The conductive water-based primer composition, wherein the modified polyolefin resin contains a non-chlorine maleic acid-modified polyolefin resin . A primer coating film formed from the conductive aqueous primer composition according to claim 1 . The primer according to claim 2 , wherein the critical surface tension γc _{substrate on} the surface of the base material and the surface tension γ _{film of the} primer coating film formed on the surface of the base material satisfy the following relational expression: Paint film.
Critical surface tension of _substrate surface γc _substrate ≧ surface tension of primer coating γ _film