JP2006037072A - Combined primer and base coating composition, method for producing decorated molded product and decorated molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combined primer and base coating composition, in which an adhesiveness between a polyolefin base material and a primer coating layer without formation of the primer coating layer is attained, having silver depositing property and smoothness of a silver plating layer, and capable of obtaining a decorated molded product superior in a coating appearance, and to provide a method for producing the decorated molded product using the composition and the decorated molded product. <P>SOLUTION: This coating forms a combined primer and base coating film, the silver plating layer and a top clear coating layer on the polyolefin base material, wherein the coating comprises a primary material (a) containing an acrylic polyol (a1), a chlorinated polyolefin modified acrylic resin (a2) and a chlorinated polyolefin resin (a3) as main materials, and a polyisocyanate hardener (b). Ratios of the solid content by mass% of (a1), (a2) and (a3) are; (a1): 40-80%, (a2): 5-45% and (a3): 1-35%, and the primary material (a) contains cyclohexane of 5-45 parts by mass based on the solid content of 100 parts by mass. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a primer / base coating composition, a method for producing a decorative molded product, and a decorative molded product.

Decorative molded products with a silver-plated layer on a plastic material have a metal-like appearance, so automobile interior parts such as meter clusters, center clusters, and center consoles, wheel caps, bumper moldings, foil garnishes, It can be used for exterior parts of automobiles such as grill radiators, back panels, door mirror covers, door handles, etc., applications other than automobile parts such as air conditioner housings, mobile phones, notebook computers and cosmetic containers.

As a method for producing these decorative molded products, for example, an undercoat layer is formed on a plastic substrate with a coating containing an alkoxytitanium ester, a silane coupling agent having an epoxy group, an epoxy resin, etc. A method of forming a plating layer and a topcoat layer is disclosed (see, for example, Patent Document 1).

However, the decorative molded product obtained by such a manufacturing method performs electroless plating in the formation of the silver plating layer, but the performance such as silver precipitation, base layer smoothness, adhesion, coating film appearance, etc. Was not enough.

As other methods for producing a decorative molded product, methods as described in Patent Documents 2 and 3 are also known. This method is a method for producing a decorative molded product by forming a base coat layer made of an organic resin on a substrate, forming a silver plating layer thereon, and then forming a top coat layer. However, the decorative molded product obtained by such a method of manufacturing a decorative molded product is not capable of sufficiently satisfying physical properties in terms of adhesion between the base layer and the silver plating layer, appearance, film performance, etc. There wasn't. In particular, since the polyolefin resin has almost no functional groups on its surface, it is difficult to obtain adhesion, and it is difficult to obtain adhesion between the polyolefin substrate and the base layer.

In order to solve such a problem, a method of forming a base coat layer after treating the substrate surface with a primer is also known. That is, a primer layer, a base coat layer, a silver plating layer, and a top coat layer are sequentially formed on a substrate. However, such a method has a problem of cost increase due to an increase in the number of painting steps for painting the primer layer. In addition, since the primer layer is made of a resin having a high affinity with the polyolefin substrate, the adhesion between the primer coat layer and the base coat layer and the adhesion of the coating film are sufficient. It was difficult.

Japanese Patent Laid-Open No. 10-309774 (2nd page) JP 2002-256454 A (2nd page) JP 2002-2564555 A (2nd page)

In view of the above-mentioned present situation, the present invention ensures sufficient adhesion between the polyolefin substrate and the coating layer without forming a primer coating layer, silver precipitation, smoothness of the silver plating layer, and coating appearance. A primer-based base paint for a decorative molded product that can provide a decorative molded product having excellent properties, a method for producing a decorative molded product using the same, and a decorative molded product It is intended.

The present invention manufactures a decorative molded article formed by forming a multilayer coating film including a silver plating layer in which a primer coating base coating layer, a silver plating layer, and a top clear coating layer are formed on a polyolefin substrate. A primer / base coating used in the method, wherein the primer / base coating is a main material (a) mainly composed of an acrylic polyol (a1), a chlorinated polyolefin-modified acrylic resin (a2), and a chlorinated polyolefin resin (a3). ) And a polyisocyanate curing agent (b), and the above (a1), (a2) and (a3) are (a1): 40 to 80% and (a2): 5 to 5% by mass solid content ratio, respectively. 45% and (a3): 1 to 35%, and the main material (a) contains 5 to 45 parts by mass of cyclohexane with respect to 100 parts by mass of the solid content. Is a Ma also serves as the base paint.

It is preferable that the polyisocyanate curing agent (b) is a polyisocyanate compound, and the primer / base coating for a decorative molded product is a two-component polyurethane coating.
Alternatively, the polyisocyanate curing agent (b) is a polyisocyanate compound blocked with a blocking agent, and is preferably a one-component polyurethane paint.

The present invention includes a step (1) of forming a primer combined base coating layer by coating the above-mentioned primer combined base coating for a decorative molded article on a polyolefin base material, and a primer combined formed by the above step (1). And a step (2) of forming a silver plating layer on the base coating film, and a step (3) of forming a top clear coating layer on the silver plating layer formed by the above step (2). It is also a method for producing a decorative molded product.
The present invention is also a decorative molded product manufactured by the above-described method for manufacturing a decorative molded product.
The present invention is described in detail below.

The primer / base coating of the present invention is a decoration obtained by forming a multilayer coating film including a silver plating layer on which a primer / base coating layer, a silver plating layer, and a top clear coating layer are formed on a polyolefin substrate. Since it is used in the manufacturing method of a molded article and also has a function as a primer, a base coating film can be formed without performing a treatment with a primer. The primer-based base paint of the present invention comprises an acrylic polyol (a1), a main material (a) mainly composed of a chlorinated polyolefin-modified acrylic resin (a2) and a chlorinated polyolefin resin (a3), and a polyisocyanate curing agent ( (a1), (a2) and (a3) are mass solid content% ratios, respectively (a1): 40-80%, (a2): 5-45% and (a3): 1- It is 35%, and the main material (a) is a base paint also serving as a primer for decorative molded products, characterized in that it contains 5-45 parts by mass of cyclohexane with respect to 100 parts by mass of the solid content.

The acrylic polyol (a1) provides adhesion to the silver plating layer and smoothness of the silver plating layer, and at the same time forms a tough coating film by causing a curing reaction with the polyisocyanate curing agent (b). It is a component. By using the chlorinated polyolefin resin (a3) in addition to the acrylic polyol (a1), it is possible to obtain adhesion and smoothness to the surface of the polyolefin material. Since the acrylic polyol (a1) and the chlorinated polyolefin resin (a3) are not compatible, the chlorinated polyolefin-modified acrylic resin (a2) is used in combination to obtain compatibility.

The acrylic polyol (a1) contained in the main material for the clear coating composition is not particularly limited as long as it is an acrylic resin containing a hydroxyl group, and may be modified.
The hydroxyl value of the acrylic polyol (a1) is preferably 40 to 120 mgKOH / g, more preferably 60 to 100 mgKOH / g. If it is less than 40 mgKOH / g, the crosslinking reaction point with the polyisocyanate curing agent may be insufficient, and the physical properties of the coating film may be insufficient. If it exceeds 120 mgKOH / g, there are too many crosslinking reaction points, In some cases, it becomes hard and brittle, and the moisture resistance and water resistance of the coating film are lowered due to excessive hydroxyl groups, which is not preferable.

The weight average molecular weight of the acrylic polyol (a1) is preferably 20000 to 150,000, more preferably 40000 to 110000. If it is less than 20000, the physical properties of the coating film tend to be lowered, and if it exceeds 150,000, the coating workability is lowered and the finished appearance tends to be lowered. In the present specification, the weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated by a polystyrene conversion method, for example.

The acrylic polyol (a1) can be obtained by polymerizing a monomer composition comprising a hydroxyl group-containing radical polymerizable monomer and other radical polymerizable monomers used as necessary by a conventional method.

The hydroxyl group-containing radical polymerizable monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate. Examples include ring-opened rings with ε-caprolactone (Placcel FA and FM series manufactured by Daicel Chemical Industries). These may be used alone or in combination of two or more.

The other radical polymerizable monomers are not particularly limited, and examples thereof include carboxylic acid group-containing monomers such as (meth) acrylic acid, maleic acid and itaconic acid, and epoxy group-containing monomers such as glycidyl (meth) acrylate, methyl (Meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene, vinyltoluene, vinyl acetate, α-methylstyrene and the like. it can. These may be used alone or in combination of two or more.

An acrylic polyol (a1) is obtained by polymerizing the monomer composition, and a conventionally known method for producing an acrylic resin can be used as a method for producing the acrylic polyol (a1). That is, although a polymerization method such as solution polymerization, non-aqueous dispersion polymerization, and bulk polymerization can be used, the solution polymerization method is suitable from the viewpoint of ease of polymerization, molecular weight adjustment, and ease of use when forming a paint. .

The chlorinated polyolefin-modified acrylic resin (a2) is prepared by heating a chlorinated polyolefin resin together with a solvent (for example, toluene, butyl acetate, a mixed solvent thereof, etc.) and dissolving the radical polymerizable acrylic monomer composition in a dissolved state. It can be obtained by charging and reacting with a radical initiator.

The chlorinated polyolefin resin used for the production of the chlorinated polyolefin-modified acrylic resin (a2) is a portion made of polyolefin substituted with chlorine atoms. Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polybutene, and water additives of copolymers such as styrene-butadiene-isoprene. You may use only a seed | species or 2 or more types together. Among them, it is preferable that the chlorinated polyolefin portion is a portion made of polypropylene substituted with a chlorine atom because it is easy to obtain and adhesion is enhanced.

The chlorine content and molecular weight of the chlorinated polyolefin portion in the chlorinated polyolefin-modified acrylic resin (a2) are not particularly limited, but the chlorine content is 18 to 30% by mass, and the molecular weight of the chlorinated polyolefin portion is 20,000 to When it is 150,000, the adhesiveness to the polyolefin material is further improved and the gasoline resistance is improved, which is preferable. The chlorine content is 20 to 25% by mass, and the molecular weight of the chlorinated polyolefin part is 50,000 to 120,000. And more preferred. When the chlorine content of the chlorinated polyolefin portion is less than 18% by mass, the compatibility with other resins is reduced, the crystallinity is high and it is difficult to melt, and the film-forming property is reduced. On the other hand, when the chlorine content exceeds 30% by mass, the adhesion to the polyolefin substrate is lowered. If the molecular weight of the chlorinated polyolefin portion is less than 20,000, the strength of the coating film obtained from the primer coating composition is low, and the water resistance and gasoline resistance are reduced. On the other hand, when the molecular weight exceeds 150,000, the wettability with respect to the polyolefin base material is reduced, the adhesiveness is lowered, and the compatibility with other resins is lowered. Turbidity may occur in the film.

The chlorinated polyolefin portion in the chlorinated polyolefin-modified acrylic resin (a2) may be a chlorinated polyolefin modified with a carboxylic acid and / or an acid anhydride to such an extent that the water resistance does not decrease. Examples of the carboxylic acid and / or acid anhydride used for modification include maleic acid, fumaric acid, maleic anhydride, citraconic acid, citraconic anhydride, itaconic acid, itaconic anhydride and the like. The amount of modification is determined in consideration of water resistance and the like, but is generally 7% or less, preferably 5% or less.

Examples of commercially available chlorinated polyolefins that can be used as the chlorinated polyolefin portion in the chlorinated polyolefin-modified acrylic resin (a2) include, for example, Hardren EH202, Hardlen 14ML, Hardlen M128P (all manufactured by Toyo Kasei Kogyo Co., Ltd.), Super Clon 822 (made by Nippon Paper Industries Co., Ltd.) can be mentioned.

The acrylic polymer chain portion in the chlorinated polyolefin-modified acrylic resin (a2) is a polymer chain grafted on the chlorinated polyolefin portion. The glass transition temperature of the acrylic polymer chain portion is not particularly limited as long as it is in the range of 0 to 60 ° C. When the glass transition temperature is less than 0 ° C., the adhesion with the polyolefin material is lowered. On the other hand, when the glass transition temperature exceeds 60 ° C., the compatibility between the acrylic polymer chain portion and the chlorinated polyolefin portion is poor, and the heat flow property is lowered. Furthermore, when the temperature exceeds 60 ° C., the coating film obtained from the primer coating composition is not smooth and is hard and poor in flexibility.

The acrylic polymer chain portion in the chlorinated polyolefin-modified acrylic resin (a2) has a structural unit derived from an acrylic monomer as an essential component, but further includes a structural unit derived from another monomer as appropriate. It may be a copolymer part. Examples of acrylic monomers include acrylic acid monomers and acrylic ester monomers such as (meth) acrylic monomers exemplified as monomers that can be used in the production of acrylic polyol (a1) described above. 1 type, or two or more types may be used in combination.

Examples of other monomers include styrene monomers such as styrene, vinyl toluene, and α-methyl styrene; hydroxyl group-containing vinyl monomers such as 4-hydroxybutyl vinyl ether and p-hydroxy styrene; allyl glycidyl ether. An epoxy group-containing monomer such as can be used, and only one type or two or more types may be used in combination.

In any case, the structural unit derived from the acrylic monomer or other monomer is selected so that the glass transition temperature of the acrylic polymer chain portion is 0 to 60 ° C. As described above, as the acrylic polymer chain portion satisfying the glass transition temperature condition, for example, a structural unit derived from butyl acrylate is a main component, and styrene, acrylic acid, methyl methacrylate, 2-hydroxyethyl is appropriately used. A structural unit derived from methacrylate or the like as a subcomponent, a structural unit derived from cyclohexyl methacrylate as a main component, or a structural unit derived from styrene, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, or the like as appropriate And the like as a subcomponent.

The method for producing the chlorinated polyolefin-modified acrylic resin (a2) is, for example, by dissolving chlorinated polyolefin in a solvent and grafting the acrylic monomer or other monomer in the presence of a peroxide. There are a polymerization method, a method of polymerizing a solution of a chlorinated polyolefin raw material monomer and the like together with the acrylic monomer and other monomers in a solvent, and the like.

The mass ratio of the chlorinated polyolefin portion (a2-1) and the acrylic polymer chain portion (a2-2) in the chlorinated polyolefin-modified acrylic resin (a2) is not particularly limited, but preferably (a2-1) / (A2-2) = 80/20 to 10/90, more preferably (a2-1) / (a2-2) = 70/30 to 30/70. When the mass ratio is less than 10/90, the mass ratio of the chlorinated polyolefin portion is lowered, and the adhesion to the polyolefin material may be lowered. On the other hand, if the mass ratio exceeds 80/20, the mass ratio of the acrylic polymer chain portion may be lowered, and water dispersibility may be lowered.

The chlorinated polyolefin resin (a3) is a resin composed of polyolefin substituted with chlorine atoms, and is the same as the chlorinated polyolefin resin (a3) used for the production of the chlorinated polyolefin-modified acrylic resin (a2) described above. Can be used. In the coating composition of the present invention, the chlorinated polyolefin resin (a3) may be the same as or different from that used in the production of the chlorinated polyolefin-modified acrylic resin (a2) used in combination.

In the main material (a), the acrylic polyol (a1) is 40 to 80% by mass with respect to 100% by mass solid content. When the content of the acrylic polyol (a1) is less than 40% by mass, the gloss of the resulting decorative molded product is lowered, and when it exceeds 80% by mass, the adhesion to the polyolefin substrate surface and the silver plating layer is lowered. To do. The lower limit is more preferably 45% by mass, and the upper limit is more preferably 76% by mass.

In the main material (a), the chlorinated polyolefin-modified acrylic resin (a2) is 5 to 45 mass% with respect to 100 mass mass. When the content of the chlorinated polyolefin-modified acrylic resin (a2) is less than 5% by mass, the stability of the coating main material is deteriorated, and the silver depositability at the time of forming the upper silver plating becomes uneven. When the gloss is lower than 45% by mass, the adhesion to the underlying plastic substrate or silver plating layer film is deteriorated. The lower limit is more preferably 10% by mass, and the upper limit is more preferably 40% by mass.

In the said main material (a), chlorinated polyolefin resin (a3) is 1-35 mass% with respect to 100% of mass solid content. When the content of the chlorinated polyolefin resin (a3) is less than 1% by mass, the adhesion to the plastic material is deteriorated, and when it exceeds 35% by mass, the gloss is deteriorated. The lower limit is more preferably 3% by mass, and the upper limit is more preferably 33% by mass.

In addition to the acrylic polyol (a1), the chlorinated polyolefin-modified acrylic resin (a2) and the chlorinated polyolefin resin (a3), the main material (a) is based on 100 parts by mass of the solid content in the main material (a). It contains 5 to 45 parts by mass of cyclohexane. If it is less than 5 parts by mass, the stability of the chlorinated polyolefin resin (a3) of the paint main material cannot be maintained, and as a result, the stability of the paint main material is lowered and the gloss of the decorative molded product is lowered. To do. When it exceeds 45 parts by mass, the solubility of the acrylic polyol (a1) becomes poor, and problems such as deterioration of the smoothness of the silver plating layer and the top clear layer, and reduction in gloss of the decorative molded product are caused. The lower limit is preferably 7 parts by mass, and the upper limit is preferably 40 parts by mass. In addition, the regulation of the content of cyclohexane described above is that the solid content of (a1) to (a3) in the coating is 100 mass when the primer / base coating for decorative molded products of the present invention is a one-component base coating. This represents the amount of cyclohexane relative to the part.

The primer / base coating composition of the present invention uses a polyisocyanate curing agent (b) in addition to the main material (a). The polyisocyanate curing agent (b) is used as a two-component polyurethane paint in which an unblocked polyisocyanate compound is put in a solution different from the main material (a) and mixed at the time of use. Alternatively, it may be a one-component polyurethane paint using a blocked polyisocyanate.

The polyisocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. For example, aromatic compounds such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate Examples include isocyanates; aliphatic isocyanates such as hexamethylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; monomers thereof and multimers such as burette type, nurate type, and adduct type. In view of good curability, the polyisocyanate is preferably a multimer.

Commercially available products of the above polyisocyanates include Sumidur N75, Sumidur N3600, Sumidur N3200-90CX (manufactured by Sumika Bayer Urethane Co., Ltd.); Coronate FH, Coronate 341 (manufactured by Nippon Polyurethane Company); Duranate THA-100, Examples include Duranate 24A-90CX, Duranate E-402-90T (manufactured by Asahi Kasei Co., Ltd.) and the like.

The blocking agent used when the polyisocyanate is blocked is not particularly limited, and examples thereof include phenols such as phenol, cresol, xylenol, chlorophenol and ethylphenol; ε-caprolactam, δ-valerolactam, γ-butyrolactam And active methylenes such as ethyl acetoacetate and acetylacetone; methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, t-butanol, amyl alcohol, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol mono 2-ethylhexyl ether, propylene glycol monomethyl ether, glycol Alcohols such as methyl acrylate, butyl glycolate, diacetone alcohol, methyl lactate and ethyl lactate, and furfuryl alcohol; oxime systems such as formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, and cyclohexane oxime Mercaptans such as butyl mercaptan, hexyl mercaptan, t-butyl mercaptan, thiophenol, methylthiophenol and ethylthiophenol; acid amides such as acetic acid amide and benzamide; imide systems such as succinimide and maleic acid imide; Examples thereof include imidazoles such as 2-ethylimidazole; secondary amines such as dimethylamine, diethylamine, and dibutylamine.

Examples of commercially available blocked isocyanates include desmotherm 2170, desmodule TPLS2759 (manufactured by Sumika Bayer Urethane Co., Ltd.); coronate C-2513, BI-120 (and above) Nippon Polyurethane Co., Ltd.); Duranate MF-K60X (Asahi Kasei Co., Ltd.) and the like. Examples of those reacted with methyl ketone oxime include Death Module BL3175, Death Module TPLS2135, Death Module S-2759-40X (or more) Sumika Bayer Urethane Co., Ltd.); Coronate C2557, Coronate 2529, Coronate C2507 (manufactured by Nippon Polyurethane Co., Ltd.) and the like.

In the primer / base coating composition of the present invention, the equivalent ratio (NCO / OH) of the NCO group in the polyisocyanate curing agent (b) to the OH group in the acrylic polyol (a1) is 1 / 1-2. / 1 is preferable. If it is less than 1/1, the adhesion between the base coating layer and the silver plating layer may be lowered, which is not preferable. If it exceeds 2/1, a rainbow may occur in the decorative molded product. The equivalent ratio (NCO / OH) is more preferably 1.1 / 1 to 1.95 / 1.

Other components such as other solvents, curing catalysts, surface conditioners, antisettling agents, antifoaming agents, and viscosity modifiers may be added to the primer / base coating composition of the present invention as necessary. Particularly preferred additives are high molecular weight surface conditioners such as organically modified polydimethylsiloxane for maintaining the deposition and smoothness of the silver plating film, and for maintaining adhesion and corrosion resistance by reacting with the silver film surface. And epoxy silane.

When the base coating composition is a two-component polyurethane coating composition comprising the main material (a) and an isocyanate compound, the base coating layer is formed by coating the two components immediately before use. can do. Formation of the base coating film layer by the application of the base coating composition can be performed by an ordinary method such as spray coating. After coating, it is preferable to perform heat curing at 60 to 100 ° C. to obtain a coating film with a cured film thickness of 20 to 30 μm.

When the base coating composition is a one-component polyurethane coating composition comprising the main material (a) and a blocked isocyanate compound, the coating can be performed by a usual method such as spray coating. After coating, it is preferable to carry out heat curing at 70 to 100 ° C. to obtain a coating film with a cured film thickness of 20 to 30 μm.

The formation method of the multilayer coating film of this invention forms a silver plating layer on the said base coating film layer. By forming a silver plating layer on the base coating layer, it is possible to form a silver plating layer with good silver precipitation and excellent appearance and adhesion.

The formation method of a silver plating layer is not specifically limited, It can carry out by the electroless plating method called a silver mirror reaction. As the most general method, an ammoniacal silver nitrate ([Ag (NH ₃ ) ₂ ] ⁺ OH ⁻ ) called a Trens reagent and a reducing agent solution are applied so as to be mixed on the surface of the base coating layer. A method can be mentioned. The reducing agent is not particularly limited, and examples thereof include sugars such as glucose; organic compounds having an aldehyde group such as glyoxal; sodium nitrite and sodium thiosulfate.

In the method for forming a multilayer coating film of the present invention, a clear coating film layer is provided on the silver plating layer. This prevents deterioration of the silver plating layer, improves the corrosion resistance, and further improves the appearance of the laminated molded product.

As the top clear paint for forming the top coat layer, those used as the top clear paint in the multilayer coating of the decorative molded product including the silver plating layer can be used. In particular, a top clear coating in consideration of interlayer adhesion between the top clear film and the silver plating film, corrosion resistance, weather resistance, etc. of the silver plating layer is preferable. From the viewpoint of weather resistance, a top clear paint containing an acrylic resin is preferable, and from the viewpoint of obtaining adhesion and anticorrosive properties of the silver plating film, an amino group-containing resin and a rust inhibitor may be contained. .

The acrylic resin is preferably a reactive hydroxyl group-containing acrylic polyol in order to obtain good film properties. As the reactive hydroxyl group-containing acrylic polyol, the same resin as the acrylic polyol (a1) can be used. Further, as other commercially available acrylic resins, Dianal LR-2586 (manufactured by Mitsubishi Rayon Co., Ltd.), Hitaroid 3371 (manufactured by Hitachi Chemical Co., Ltd.) and the like can be used. The reactive hydroxyl group-containing acrylic polyol may be a solution-type resin or a non-aqueous dispersion resin (NAD). Examples of commercially available non-aqueous dispersion resins include SETALAX 1850 ss-50 (manufactured by Akzo Nobel) and Hitaroid 6110 (manufactured by Hitachi Chemical Co., Ltd.).

Examples of the amino group-containing resins, acrylic resins are preferable containing an amino group, more preferably an acrylic resin having a dialkylamino group represented by -N-R ₂ in a side chain. The amino group-containing resin can be obtained by using a tertiary amino group-containing radical polymerizable monomer as a monomer by the same production method as the acrylic polyol (a1).

The clear coating composition preferably contains a curing agent. It does not specifically limit as a hardening | curing agent, For example, polyisocyanate etc. can be mentioned. The polyisocyanate may be a polyisocyanate that can be used in the above-described primer-coating base coating composition, and may be a blocked polyisocyanate compound. In view of excellent weather resistance, aliphatic polyisocyanates and / or alicyclic polyisocyanates are preferred.

Examples of the rust inhibitor include fatty acid-modified amide compounds. If necessary, the top clear coating composition may include other solvents such as butyl acetate, xylene and toluene; a curing catalyst; a light stabilizer such as Sanol LS-292 (manufactured by Sankyo); and an ultraviolet light such as tinuvin 384. An absorbent; a surface modifier; an antifoaming agent; a viscosity modifier; an anti-settling agent and the like may be blended.

The clear coating composition is a mixture prepared by mixing the above-mentioned components immediately before use. The formation of the clear coating layer by the application of the clear coating composition can be performed by a usual method such as spray coating. After coating, it is preferable to carry out heat curing at 60 to 100 ° C. to obtain a coating film having a cured film thickness of 20 to 40 μm. There exists a possibility that corrosion resistance and an external appearance may deteriorate that a dry film thickness is less than 20 micrometers. When the dry film thickness exceeds 40 μm, it is not preferable in terms of sagging and peeling. The dry film thickness of the clear coating layer is more preferably 25 to 35 μm.

The plastic material to which the method for forming a multilayer coating film of the present invention is applied is preferably a polyolefin material, and examples thereof include polypropylene (PP), olefinic thermoplastic elastomer (TPO), and mixtures thereof. These can use what was shape | molded by well-known shaping | molding methods, such as injection molding and extrusion molding.

The plastic material does not necessarily have to be treated on the surface of the plastic material before applying the primer / basecoat coating composition of the present invention. In order to improve the quality, it is preferable to perform a washing treatment and drying before the application of the primer / basecoat coating composition. The said drying process and drying may be performed by a normal method.

The formation method of the multilayer coating film of this invention forms a silver plating layer on the said base coating film layer. By forming a silver plating layer on the base coating layer, it is possible to form a silver plating layer with good silver precipitation and excellent appearance and adhesion. A decorative molded product obtained by such a method is also a part of the present invention.

The primer / base coating composition of the present invention ensures sufficient adhesion between the polyolefin substrate and the coating layer without forming a primer coating layer, and is capable of precipitating silver, smoothing the silver plating layer, and coating. A decorative molded product having excellent properties in film appearance can be obtained.

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “part” means “part by mass” unless otherwise specified, and “%” means “% by mass” unless otherwise specified.

Production Example 1 Preparation of acrylic polyol (a1) In a reaction vessel equipped with a stirrer, thermometer, reflux tube, dropping funnel, nitrogen introduction tube and thermostat-equipped heating device, 2 parts by mass of propylene glycol monomethyl ether (PGME), butyl acetate 8.57 parts by mass, 8.57 parts of toluene, and 5 parts by mass of an aromatic hydrocarbon solvent (“Sorvesso 100” manufactured by Exxon) were charged, and the internal temperature was raised to 110 ° C. while stirring.
Next, 37.35 parts by mass of methyl methacrylate, 2.07 parts by mass of methacrylic acid and 44.08 parts of n-butyl methacrylate, 16.5 parts by mass of hydroxypropyl acrylate, 1 part by mass of PGME, 4 parts by mass of butyl acetate, An initiator solution consisting of 4 parts by weight of toluene, 1 part by weight of “Sorbesso 100” and 2.2 parts by weight of a peroxide polymerization initiator (“Kaya Ester O” manufactured by Nippon Kayaku Co., Ltd.) is added to each of two dropping funnels. It put separately and was dripped over 3 hours, and superposition | polymerization was started. During this time, the internal temperature was maintained at 110 ° C., and after completion of the dropping, 1 part by mass of PGME, 1.5 parts by mass of butyl acetate, 1 part by mass of “Solvesso 100”, 1.5 parts by mass of toluene and “Kayaester O” A solution consisting of 0.3 parts by mass was added dropwise over 2 hours while maintaining the internal temperature at 110 ° C. to complete the polymerization, and after cooling the internal temperature to 80 ° C., 40.76 parts by mass of toluene was added to acetic acid. 17 parts by mass of butyl were charged in order to obtain an acrylic resin varnish A. The solid content of the acrylic resin varnish was 50% by mass.
Further, the weight average molecular weight was about 70,000 as measured by gel permeation chromatograph in terms of styrene.

The acrylic resin varnish was measured for solid content by collecting the acrylic resin varnish (Xg) in a non-volatile content measurement aluminum dish and drying it at 110 ° C. for 3 hours, and then measuring the residual solid content (Yg). Calculated by the formula.
Resin solid content (mass%) = [(Y) / (X)] × 100

Production Example 2 Preparation of chlorinated polyolefin resin varnish (polyolefin resin varnish a3)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux tube, a dropping funnel, a nitrogen introducing tube, and a thermostat-equipped heating device, 56 parts by mass of toluene, 24 parts by mass of butyl acetate and acid anhydride-modified chlorinated polypropylene resin (“Hardylene” M128P ”manufactured by Toyo Kasei Kogyo Co., Ltd .: chlorine content 21 mass%, weight average molecular weight 40,000) 20 parts by mass was charged and heated to 110 ° C. while stirring and heated for 1 hour to obtain polyolefin resin varnish B. The solid content was 20% by mass.

Production Example 3 Preparation of chlorinated polypropylene-modified acrylic resin (polyolefin resin varnish a2)
In a reaction vessel equipped with a stirrer, thermometer, reflux tube, dropping funnel, nitrogen introduction tube, and thermostat-equipped heating device, 7 parts by mass of propylene glycol monomethyl ether, 58 parts by mass of toluene, 23 parts by mass of butyl acetate and acid anhydride 20 parts by mass of modified chlorinated polypropylene resin (“Hardlen M128P” manufactured by Toyo Kasei Kogyo Co., Ltd.) was charged, and the internal temperature was raised to 110 ° C. while stirring. Next, 30 parts by mass of methyl methacrylate, 3 parts by mass of methacrylic acid, 40 parts by mass of n-butyl methacrylate, 7 parts by mass of 2hydroxyethyl methacrylate, 4 parts by mass of propylene glycol monomethyl ether, 12 parts by mass of toluene , 5 parts by mass of butyl acetate and a peroxide-based polymerization initiator (“Kaya Ester O” manufactured by Nippon Kayaku Co., Ltd.) 2.2 parts by mass of polymerization initiator solution were charged in separate dropping funnels, respectively. The solution was added dropwise over 3 hours while stirring at 110 ° C. Further, it was composed of 1 part by mass of propylene glycol monomethyl ether, 2 parts by mass of toluene, 1 part by mass of butyl acetate, and 0.3 parts by mass of “Kayaester O”. The polymerization initiator solution was added dropwise over 2 hours while maintaining and stirring the internal temperature at 110 ° C. to complete the reaction. The solid resin content was 47 wt%.

Production Example 4 Preparation of Primer / Base Paint (A) Coating Liquid For the two-part curable polyurethane paint, immediately before painting, and for the one-part polyurethane, first put the main material (a ) And stirring, dilute solvent (D) (acetic acid butyl ester / methyl isobutyl ketone / toluene / ipzol = 35/10/32/23: mass ratio) at a ratio of 1: 1 with respect to the main material, Subsequently, each isocyanate curing agent was charged and stirred for 15 minutes to prepare a primer / base coating (A) coating solution.
Two-component polyurethane coating composition: Sumijour N3500 (manufactured by Sumika Bayer, nonvolatile content = 75%) was used as an isocyanate curing agent.
One-component polyurethane coating composition: Desmodur LS2759-40X (manufactured by Sumika Bayer Urethane Co., Ltd., nonvolatile content = 38%), which is a block type isocyanate, was used as an isocyanate curing agent.
About the compounding quantity of the hardening | curing agent in each Example and a comparative example, it is as Table 1, Table 2, and Table 3.

Production Example 5 Preparation of Top Clear Paint Coating Liquid (c1) The top clear paint coating liquids (c1) for Examples 1 to 6 and Example 9 and Comparative Examples 1 to 7 were R241 Top Clear (manufactured by Nippon Bee Chemical Co., Ltd.). To 100 parts of the paint using a two-component curable polyurethane paint), 50 parts of the dilution solvent B was added and diluted to prepare a top clear paint coating liquid.

Production Example 6 Preparation of top clear paint coating liquid (c2)
The clear coating composition (c2) in Example 7 is composed of 167 parts of an acrylic polyol resin “Dyanal LR-2586” (manufactured by Mitsubishi Rayon Co., Ltd., 45% non-volatile content), a tertiary amino group-containing acrylic resin “Acridic GZ- 169 "(Dainippon Ink Chemical Co., Ltd., non-volatile content 48%) 52 parts, surface conditioning agent" SH-2000-100CS "(Toray Dow Corning Silicone) 2 parts, light stabilizer" Sanol LS-292 " (Sankyo Co., Ltd.) 1 part, UV absorber “Tinubin 384” (Ciba Specialty Chemicals Co., Ltd., 90% solids xylene solution) 3.6 parts, 16 parts acetic acid butyl ester are stirred in a container equipped with a stirrer. The main ingredients of the clear paint were adjusted in order while mixing. Prior to coating, the diluent (D) was charged and diluted at a mass ratio of 1: 1 with the main material while stirring the main material, and then the two-component curable polyisocyanate curing agent “Duranate 24A-90PX”. (Asahi Kasei Co., Ltd., non-volatile content 90%) was charged in 16 parts to prepare a clear coating liquid. The coating liquid was used for forming the clear film in Example 7.

Production Example 7 Preparation of top clear paint coating liquid (c3)
167 parts of “Dianar LR2586”, 50 parts of non-aqueous dispersion type acrylic resin “Cetalux 1850ss-50” (manufactured by Akzo Nobel, nonvolatile content 50%), 2 parts of “SH-2000-100CS”, “Sanol LS-” 292 "1.7 parts," Tinuvin 384 "4.6 parts, acetic acid butyl ester 38 parts in the same manner as in the above (c2) to prepare the clear coating material, and in the same procedure, the dilution solvent After diluting (D) with the main material at a 1: 1 ratio, 16 parts of “Duranate 24A-90PX” was added, and after stirring for 15 minutes, a clear coating liquid was obtained. The coating liquid was used for forming the top clear film of Example 8.

(Creation of specimen)
Pretreatment of base material made of polypropylene and formation of primer-coating base coating 70 × 100 × 3 mm polypropylene base material is washed with isopropanol and dried, and then the primer-coating base coating composition is spray-coated so as to have a dry film thickness of 18 μm. And dried at 80 ° C. for 10 minutes.

(Formation of silver plating layer)
On the test piece on which the base layer was formed, a 0.2% hydrochloric acid solution of 0.2% tin (II) chloride was applied to the surface of the coating film and then washed with water. By simultaneously applying a mixed aqueous solution of silver nitrate and excess ammonia and a glucose solution on the test piece after washing with water on the test piece, a uniform silver plating film of about 20 μm is formed, and the residue is removed by washing with water. A test piece having a silver plating layer formed on the base layer was obtained.

(Formation of clear layer)
On the test piece on which the silver plating layer was formed, the clear paint was spray-coated so as to have a cured film thickness of 30 μm and cured at 80 ° C. for 20 minutes to obtain a test piece on which a clear layer was formed.
The obtained test piece was evaluated by the following evaluation method. The results are shown in Tables 1 and 2.

(Evaluation methods)
Storage stability In each example and comparative example, the two-component curable primer / base coating is the main material (a), and the one-component curable coating is 200 g each in a 500 ml tin can and sealed. After storage at 40 ° C. for 10 days, the sample was stirred with a glass rod and judged based on the following criteria.
◯: There is no thickening of the composition.
X: Significant thickening or gelation is observed.

The formation state of the silver depositing silver plating film was visually observed and judged based on the following criteria.
A: The silver plating film is uniformly formed.
X: The silver plating film is formed unevenly.

The appearance of the test pieces of Examples and Comparative Examples was observed based on the following criteria by visual observation of the appearance of the coating film.
○: No appearance abnormality such as interference fringes, turbidity, glossy blur, and smoothness abnormality.
X: Appearance abnormalities such as interference fringes, turbidity, glossy blur, and smoothness abnormality are observed.

Adhesiveness: Secondary adhesion to hot water After immersion in hot water of 40 ° C. for 10 days, the surface water was wiped off and left at 25 ° C. for 1 hour. Thereafter, a cross cellophane tape peeling test was performed according to JIS K5400, and the determination was made based on the following criteria.
◯: There are no squares to peel off, and there is no chipping in the cut part.
X: There are squares to be peeled off or there are chipped cut portions.

From the results of Table 1, Table 2, and Table 3, the decorative molded product obtained using the primer / base coating composition of the present invention has a silver deposition property, coating adhesion, and coating appearance. It is clear that the decorative molded product of the comparative example is not suitable for use because it is superior in properties but is inferior in either property.

The clear coating composition of the present invention is excellent in adhesion between the base coating film, the polyolefin base material and the silver plating layer, and has excellent appearance characteristics. Therefore, automobiles such as meter clusters, center clusters, center consoles, etc. Interior parts, wheel caps, bumper moldings, foil garnishes, grill radiators, back panels, door mirror covers, door handles and other automotive exterior parts, air conditioner housings, mobile phones, laptop computers, cosmetic containers and other uses other than automotive parts Can be used for painting.

Claims (5)

Used in a method for producing a decorative molded product formed by forming a multilayer coating film including a silver plating layer in which a primer coating base coating layer, a silver plating layer, and a top clear coating layer are formed on a polyolefin substrate. It is a primer combined base paint,
The primer combined base paint is composed of an acrylic polyol (a1), a main material (a) mainly composed of a chlorinated polyolefin-modified acrylic resin (a2) and a chlorinated polyolefin resin (a3), and a polyisocyanate curing agent (b). Become
Said (a1), (a2) and (a3) are (a1): 40 to 80%, (a2): 5 to 45% and (a3): 1 to 35%, respectively, in mass solid content ratio.
The base material (a) contains 5 to 45 parts by mass of cyclohexane with respect to 100 parts by mass of a solid content. The polyisocyanate curing agent (b) is a polyisocyanate compound,
2. The primer / base coating for a decorative molded product according to claim 1, which is a two-component polyurethane coating. The polyisocyanate curing agent (b) is a polyisocyanate compound blocked with a blocking agent,
The base paint also used as a primer for decorative molded products according to claim 1, which is a one-component polyurethane paint. A step (1) of forming a primer / base coating layer by applying the primer / base coating for a decorative molded article according to claim 1, 2 or 3 on a polyolefin substrate;
A step (2) of forming a silver plating layer on the primer combined base coating film formed by the step (1);
A process for producing a decorative molded product comprising the step (3) of forming a top clear coating layer on the silver plating layer formed by the step (2). A decorative molded product manufactured by the method for manufacturing a decorative molded product according to claim 4.