JP2016000770A - Base paint composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base paint composition that also serves as a primer, eliminating the need for using a primer coating layer, in a multilayer coating for automobile interior components.SOLUTION: A base paint composition comprises an acrylic resin (A-1) with a hydroxyl value of 40-120 mgKOH/g, a chlorinated polyolefin resin (A-2), an acryl modified chlorinated polyolefin resin (A-3), and a polyisocyanate curing agent (A-4) that is a polyisocyanate compound blocked with a blocking agent. Based on the total weight of (A-1), (A-2), (A-3) and (A-4), the amount of the acrylic resin (A-1) is 40-65 wt.%, the amount of the chlorinated polyolefin resin (A-2) is 5-18 wt.%, and the amount of the acryl modified chlorinated polyolefin resin (A-3) is 20-30 wt.%.

Description

  The present invention relates to a base coating composition for automobile interior parts and a multilayer coating film obtained by using this composition.

  Many painted resin parts are used for automobile interior parts. Such a resin component usually has a structure in which a base coating layer and a clear coating layer are sequentially laminated on a resin base material. When the base coating layer is difficult to adhere on the resin base material, The primer coating layer is further provided on the resin substrate, and the base coating layer and the clear coating layer are sequentially laminated thereon.

  As a paint composition for automobile interior parts, for example, in Patent Document 1, as a resin component in a primer-use color base paint for automobile resin parts having a primer-use color base coating layer and a clear coating layer on a resin substrate, A coating composition for automotive resin parts, characterized by using a copolymer obtained by grafting a polymer having a solubility parameter close to that of the resin substrate and a polymer having a solubility parameter close to the clear coating layer Things are listed.

  Further, Patent Document 2 includes a polyester polyol containing a trifunctional or higher functional polyol and lactic acid as constituents in an amount of 80 mol% or more, a hydroxyl value of 140 to 240 mgKOH / g, and 70 mol% or more of hydroxyl groups being secondary hydroxyl groups ( A-1) formed with a base coating composition containing an acrylic resin (A-2) and a polyisocyanate (A-3) having a hydroxyl value of 30 to 80 mg KOH / g and a glass transition point of 40 to 80 ° C. A base coating layer, and a polyester polyol formed on the base coating layer and obtained by polymerization of a raw material composition comprising a tri- or higher functional polyol, sebacic acid and diol, and having a hydroxyl value of 140 to 240 mgKOH / g (B-1), an acrylic resin (B-2) having a hydroxyl value of 120 to 220 mgKOH / g, and Raven multilayer coating film and having a clear coating film layer formed by a clear coating composition containing the polyisocyanate (B-3) are described.

  In recent years, resin base materials used for automobile interior parts are diversified from the viewpoints of cost and moldability. As such a resin base material, ABS resin (acrylonitrile, butadiene and styrene copolymer resin), PC resin (polycarbonate resin) / ABS resin, and PP resin (polypropylene resin) are known. Conventionally, when an ABS resin substrate is used, a resin component in which a base coating layer and a clear coating layer are sequentially laminated on the ABS resin substrate has been used. On the other hand, when PP resin is used as the resin base material, it is difficult to adhere the PP resin base material and the base coating layer because the PP resin has almost no functional group on its surface. For this reason, when using PP resin as a resin base material, the method of processing a PP resin base material surface with a primer, forming a primer coating film layer, and forming a base coating film layer on it has been taken. However, this method has a problem of cost increase due to an increase in the number of painting steps for painting the primer coating layer. In addition, the primer coating layer is made of a resin having a high affinity with a polyolefin base material such as PP resin, but the adhesion between the primer coating layer and the base coating layer is sufficient. It was difficult to be.

JP-A-11-181332 JP2013-193225A

  As described above, in the conventional coating film for automobile interior parts, when PP resin is used as a base material, a primer coating layer has to be added below the base coating layer. Therefore, an object of the present invention is to provide a primer / base coating composition that does not require the use of a primer coating layer in a coating for automobile interior parts.

  As a result of various studies on means for solving the above problems, the present inventors have found that the base coating composition contains an acrylic resin, a chlorinated polyolefin resin, an acrylic-modified chlorinated polyolefin resin, and a polyisocyanate curing agent with a specific content. It has been found that a primer-coating base coating composition that does not require the use of a primer coating layer can be provided, and the present invention has been completed.

That is, the gist of the present invention is as follows.
(1) Acrylic resin (A-1) having a hydroxyl value of 40 to 120 mgKOH / g, chlorinated polyolefin resin (A-2), acrylic-modified chlorinated polyolefin resin (A-3), and poly blocked with a blocking agent A base coating composition containing a polyisocyanate curing agent (A-4) which is an isocyanate compound,
The amount of the acrylic resin (A-1) is 40 to 65% by weight based on the total weight of (A-1), (A-2), (A-3) and (A-4), and chlorinated. A base coating composition in which the amount of the polyolefin resin (A-2) is 5 to 18% by weight and the amount of the acrylic-modified chlorinated polyolefin resin (A-3) is 20 to 30% by weight.
(2) A multilayer coating film having a base coating layer formed from the base coating composition of (1) and a clear coating layer formed on the base coating layer, wherein the clear coating layer is Polyester polyol (B-1) obtained by polymerization of a raw material composition comprising a tri- or higher functional polyol, sebacic acid and diol, having a hydroxyl value of 140 to 240 mgKOH / g, a hydroxyl value of 120 to 220 mgKOH / g, A multilayer coating film formed from a clear coating composition containing an acrylic resin (B-2) having a glass transition point of 0 to 40 ° C., a polyisocyanate curing agent (B-3) and a condensing dye (B-4) .

  According to the present invention, it is possible to provide a primer / base coating composition that does not require the use of a primer coating layer in a coating for automobile interior parts.

Hereinafter, preferred embodiments of the present invention will be described in detail.
I. Base coating composition The base coating composition of the present invention comprises an acrylic resin (A-1), a chlorinated polyolefin resin (A-2), an acrylic-modified chlorinated polyolefin resin (A-3), and a polyisocyanate curing agent (A- 4). Since the base coating composition of the present invention is a primer-coating base coating composition that also functions as a primer, the base coating layer can be formed on the resin substrate without treating the resin substrate with the primer. .

  The base coating composition of the present invention preferably does not contain cyclohexane. By not containing cyclohexane, it becomes possible to use a highly polar acrylic resin (A-1) or polyisocyanate curing agent (A-4), and the range of selection is expanded.

1. Acrylic resin (A-1)
The base coating composition of the present invention is 40 to 65% by weight, preferably 30 to 50% by weight based on the total weight of (A-1), (A-2), (A-3) and (A-4). % Acrylic resin (A-1). When the content of the acrylic resin (A-1) in the base coating composition is within this range, the resulting base coating composition can disperse the pigment without being separated. Even if it is a case where it coats to any of a resin base material and an ABS resin base material, a coating film has the outstanding coating-film external appearance and adhesiveness with a resin base material.

  The acrylic resin (A-1) used in the base coating composition of the present invention is not particularly limited as long as it is an acrylic resin containing a hydroxyl group, and may be modified, but the hydroxyl value is 40 to 40. 120 mgKOH / g, preferably 60-100 mgKOH / g. When the hydroxyl value is within this range, the polyisocyanate curing agent is sufficiently cross-linked, so that sufficient film properties can be obtained, the film does not become hard and brittle, and the excess hydroxyl groups cause This is because the moisture resistance and water resistance are not lowered.

  The glass transition point of the acrylic resin (A-1) is preferably −10 to 60 ° C. When the glass transition point is within this range, an excellent effect can be obtained in terms of long-term stability such as weather resistance.

  The weight average molecular weight of acrylic resin (A-1) becomes like this. Preferably it is 5000-100000, More preferably, it is the range of 8000-50000. This is because when the weight average molecular weight of the acrylic resin is within this range, the physical properties, coating workability, and finished appearance of the coating film are good. 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 resin (A-1) 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. For example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate is ε -What was ring-opened with caprolactone (Daicel Chemical Industries Plaxel FA and FM series) etc. can be mentioned. These may be used alone or in combination of two or more.

  Other radical polymerizable monomers are not particularly limited. For example, in addition to 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 ( Examples include 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. . These may be used alone or in combination of two or more.

  An acrylic resin (A-1) can be obtained by polymerizing the monomer composition. As a method for producing the acrylic resin (A-1), a conventionally known method for producing an acrylic resin can be used. Polymerization methods such as water dispersion polymerization and bulk polymerization can be used, but the solution polymerization method is suitable from the viewpoint of ease of polymerization, molecular weight adjustment, and ease of use when forming a paint.

2. Chlorinated polyolefin resin (A-2)
The base coating composition of the present invention comprises 5-18% by weight of chlorinated polyolefin resin (A) based on the total weight of (A-1), (A-2), (A-3) and (A-4). -2). When the content of the chlorinated polyolefin resin (A-2) in the base coating composition is within this range, the coating composition is not separated, and the base coating composition is treated with a PP resin base and an ABS resin base. Even if it coats any of these, a coating film has the outstanding coating-film external appearance and the adhesiveness with a resin base material.

  The chlorinated polyolefin resin (A-2) used in the base coating composition of the present invention is a polyolefin resin substituted with chlorine atoms. Chlorination of the polyolefin resin can be carried out by conventional techniques. For example, it can be easily chlorinated by blowing a chlorine gas of polyolefin at a high temperature with a chlorine gas. 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 is chlorinated polypropylene because it is easy to obtain and the adhesion to the resin base material is increased.

  The chlorine content and molecular weight of the chlorinated polyolefin resin (A-2) are not particularly limited, but from the viewpoints of compatibility with other resins, film-forming properties, and water resistance of the resulting coating film, Is 18 to 30% by weight, the molecular weight is preferably 20,000 to 150,000, the chlorine content is 20 to 25% by weight, and the molecular weight of the chlorinated polyolefin is more preferably 50,000 to 120,000.

  The chlorinated polyolefin resin (A-2) 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 resin (A-2) include, for example, HARDREN EH202, HARDLEN 14ML, HARDLEN M128P (all manufactured by Toyo Kasei Kogyo Co., Ltd.), Super Clone 822 (Nippon Paper Industries Co., Ltd.) Manufactured).

3. Acrylic modified chlorinated polyolefin resin (A-3)
The base coating composition of the present invention comprises 20 to 30% by weight of acrylic-modified chlorinated polyolefin resin based on the total weight of (A-1), (A-2), (A-3) and (A-4) (A-3) is contained. When the content of the acrylic-modified chlorinated polyolefin resin (A-3) in the base coating composition is within this range, the base coating composition has good compatibility, and the base coating composition is made of a PP resin substrate. And even if it is a case where it coats to any of an ABS resin base material, a coating film has the outstanding coating-film external appearance and adhesiveness with a resin base material.

  The weight ratio of the chlorinated polyolefin resin (A-2) to the acrylic-modified chlorinated polyolefin resin (A-3) in the base coating composition of the present invention is preferably 1: 1.1 to 1: 7.5. From the viewpoint of good compatibility of the base coating composition and good adhesion of the base coating layer to the resin substrate, it is particularly preferably 1: 1.25 to 1: 1.35.

  The acrylic-modified chlorinated polyolefin resin (A-3) used in the base coating composition of the present invention is a state in which the chlorinated polyolefin resin is heated and dissolved together with a solvent (for example, toluene, butyl acetate, a mixed solvent thereof or the like). The radical polymerizable acrylic monomer composition can be obtained by charging and reacting with a radical initiator.

  As chlorinated polyolefin resin used for manufacture of acrylic modified chlorinated polyolefin resin (A-3), said chlorinated polyolefin resin (A-2) can be used.

  The acrylic polymer chain portion in the acrylic-modified chlorinated polyolefin resin (A-3) is a polymer chain grafted to the chlorinated polyolefin. 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.

  The acrylic polymer chain portion in the acrylic-modified chlorinated polyolefin resin (A-3) has a structural unit derived from an acrylic monomer as an essential component, but a co-polymer further including structural units derived from other monomers as appropriate. It may be a combined part. Examples of the acrylic monomer include acrylic acid monomers and acrylic acid ester monomers such as (meth) acrylic monomers exemplified as monomers that can be used in the production of the acrylic resin (A-1). You may use together 1 type, or 2 or more types.

  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; epoxy group-containing monomers such as allyl glycidyl ether. Etc., and only one kind or two or more kinds 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. Examples of the acrylic polymer chain portion that satisfies the glass transition temperature condition include, for example, a structural unit derived from butyl acrylate as a main component, and styrene, acrylic acid, methyl methacrylate, 2-hydroxyethyl methacrylate as appropriate. Including structural units derived from, for example, structural units derived from cyclohexyl methacrylate as a main component, and structural units derived from styrene, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, etc., as appropriate. What is contained as a subcomponent is mentioned.

  The method for producing the acrylic-modified chlorinated polyolefin resin (A-3) is, for example, a method in which chlorinated polyolefin is dissolved in a solvent, and the acrylic monomer or other monomer is graft-polymerized in the presence of a peroxide. Alternatively, there is a method of polymerizing a solution of a chlorinated polyolefin raw material monomer in a solvent together with the acrylic monomer and other monomers.

  The weight ratio of the chlorinated polyolefin portion (A3-1) and the acrylic polymer chain portion (A3-2) in the acrylic-modified chlorinated polyolefin resin (A-3) is not particularly limited, but preferably (A3-1) / (A3-2) = 80/20 to 10/90, and more preferably (A3-1) / (A3-2) = 70/30 to 30/70. This is because when the weight ratio is within this range, good adhesion and water dispersibility to a polyolefin substrate such as polypropylene can be obtained.

4). Polyisocyanate curing agent (A-4)
The base coating composition of the present invention is preferably 6.5 to 9.5% by weight based on the total weight of (A-1), (A-2), (A-3) and (A-4). Particularly preferably, the polyisocyanate curing agent (A-4) is contained in an amount of 7.5 to 8.5% by weight. When the content of the polyisocyanate curing agent (A-4) in the base coating composition is within this range, a coating film having sufficient adhesion can be obtained.

  The polyisocyanate curing agent (A-4) used in the base coating composition of the present invention is a polyisocyanate compound blocked with a blocking agent.

  The polyisocyanate compound is not particularly limited, and for example, a compound having two or more isocyanate groups can be used. For example, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, metaxylylene. Examples include aromatic isocyanates such as range 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. it can. In view of good curability, the polyisocyanate is preferably a multimer.

  The blocking agent for blocking the polyisocyanate is not particularly limited, and examples thereof include phenols such as phenol, cresol, xylenol, chlorophenol and ethylphenol; ε-caprolactam, δ-valerolactam, γ-butyrolactam and β-pro Lactams such as piolactam; 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 mono-2-ethylhexyl ether, propylene glycol monomethyl ether, methyl glycolate, butyl glycolate, diacetone alcohol Alcohol, methyl lactate and ethyl lactate, furfuryl alcohol, etc .; formaldoxime, acetoaldoxime, acetoxime, methylethylketoxime, diacetylmonooxime, cyclohexaneoxime, and other oxime systems; butyl mercaptan, hexyl mercaptan, t-butyl Mercaptans such as mercaptan, thiophenol, methylthiophenol and ethylthiophenol; acid amides such as acetic acid amide and benzamide; imides such as succinimide and maleic imide; imidazoles such as imidazole and 2-ethylimidazole; dimethyl Secondary amines such as amine, diethylamine and dibutylamine can be exemplified.

  Commercially available isocyanates blocked with the above blocking agent include, for example, desmotherm 2170, desmodule TPLS2759 (manufactured by Sumika Bayer Urethane Co., Ltd.); coronate C-2513, BI-120 (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. (Sumika Bayer Urethane Co., Ltd.); Coronate C2557, Coronate 2529, Coronate C2507 (manufactured by Nippon Polyurethane Co., Ltd.) and the like.

  In the base coating composition of the present invention, the equivalent ratio (NCO / OH) of the NCO group in the polyisocyanate curing agent (A-4) to the OH group in the acrylic resin (A-1) is obtained. From the viewpoint of film adhesion, it is preferably 1/1 to 2/1, and more preferably 1.1 / 1 to 1.95 / 1.

  The base coating composition of the present invention includes a pigment, an organic solvent, a curing catalyst, a surface conditioner, an anti-settling agent, an antifoaming agent, a viscosity modifier, a glittering material aligning agent, an ultraviolet absorber (UVA), etc. The component may be contained. Examples of pigments that can be used in the base coating composition of the present invention include metallic pigments, colored pigments, and extender pigments. Examples of metallic pigments include aluminum flakes, copper bronze flakes, mica-like iron oxides, mica flakes, mica-like iron oxides coated with metal oxides, mica flakes coated with metal oxides, and the like. Examples of the color pigment include inorganic pigments such as titanium dioxide, iron oxide, chromium oxide, lead chromate, and carbon black; azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, and perinones. And organic pigments such as pigments, perylene pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, benzimidazolone pigments, diketopyrrolopyrrole pigments, and metal complex pigments. Examples of extender pigments include talc, calcium carbonate, precipitated barium sulfate, and silica. These may be used alone or in combination of two or more.

II. Clear coating composition The clear coating composition of the present invention comprises a polyester polyol (B-1), an acrylic resin (B-2), a polyisocyanate curing agent (B-3), and a condensing dye (B-4).

1. Polyester polyol (B-1)
The polyester polyol (B-1) used in the clear coating composition of the present invention is obtained by polymerization of a raw material composition comprising a trifunctional or higher functional polyol, sebacic acid and a diol.

  Examples of the tri- or higher functional polyol include trimethylolpropane, pentaerythritol, glycerin, mannitol, xylitol and the like.

  The diol is not particularly limited, and 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol And diols such as bisphenol A alkylene oxide adduct, bisphenol S alkylene oxide adduct, and 1,2-propanediol.

  The polyester polyol (B-1) preferably has a sebacic acid content in the range of 20 to 70% by weight. The polyester polyol (B-1) preferably has a trifunctional or higher polyol content in the range of 20 to 80% by weight.

  The polyester polyol (B-1) preferably has a number average molecular weight of 1000 to 3500. By setting it as the thing within the said range, it becomes suitable crosslinking density, and it is preferable at the point that the coating film excellent in water resistance, moisture resistance, and chemical resistance can be formed.

  The polyester polyol (B-1) preferably has an acid value in the range of 0.5 to 1.5 mgKOH / g. It is preferable in the above range that water resistance and alkali resistance are improved.

  The polyester polyol (B-1) is obtained by polymerization of a monomer composition comprising the above components. In the said monomer composition, another monomer may be contained in the range which does not prevent the physical property required in this invention. The other monomer is preferably less than 70% by weight.

  The polyester polyol (B-1) has a hydroxyl value of 140 to 240 mgKOH / g. By having a hydroxyl value in the above range, the crosslinking density of the coating film becomes sufficient, and properties such as water resistance and moisture resistance become sufficient.

  The content of the polyester polyol (B-1) in the clear coating composition of the present invention is, for example, 30 to 90% by weight, preferably 45 to 80% by weight based on the total weight of (B-1) and (B-2). % By weight. When the content of the polyester polyol (B-1) in the clear coating composition of the present invention is within this range, sufficient scratch recovery is exhibited even at room temperature, the coating film properties are good, and adhesion after moisture resistance and chemical resistance Excellent in properties.

2. Acrylic resin (B-2)
The acrylic resin (B-2) used in the clear coating composition of the present invention is not particularly limited as long as it is an acrylic resin containing a hydroxyl group, but is an acrylic resin having a hydroxyl value of 120 to 220 mgKOH / g. By using such an acrylic resin, the coating film has an appropriate crosslinking density, which is preferable in terms of water resistance and weather resistance.

  The acrylic resin (B-2) has a glass transition point of 0 to 40 ° C. When the glass transition point is within this range, an excellent effect can be obtained in terms of long-term stability such as weather resistance.

  The acrylic resin (B-2) preferably has an acid value of 0.2 to 2.0 mgKOH / g. Use of such an acrylic resin is preferable in that the water resistance and alkali resistance of the coating film are good.

  The acrylic resin (B-2) preferably has a number average molecular weight of 2000 to 20000. By setting it as the thing within the said range, it is preferable at the point that a coating-film physical property and coating workability | operativity are favorable.

  The weight average molecular weight of the acrylic resin (B-2) is preferably in the range of 3000 to 45000, more preferably in the range of 3500 to 35000, from the viewpoint of the physical properties of the coating film and the coating workability.

  An acrylic resin (B-2) can be manufactured by the method similar to an acrylic resin (A-1) using the monomer illustrated in said acrylic resin (A-1).

3. Polyisocyanate curing agent (B-3)
As the polyisocyanate curing agent (B-3) used in the clear coating composition of the present invention, those exemplified for the polyisocyanate curing agent (A-4) can be used.

  In the clear coating composition of the present invention, the amount of the polyisocyanate curing agent (B-3) is such that the NCO group in the polyisocyanate curing agent (B-3), the OH group in the polyester polyol (B-1), and the acrylic resin. The total equivalent ratio (NCO / OH) with the OH group in (B-2) is 0.8 / 1 to 1.2 / 1 in consideration of the strength, weather resistance and hardness of the clear coating layer to be obtained. It is preferable to adjust so that. When content of the polyisocyanate hardening | curing agent (B-3) in the clear coating composition of this invention exceeds this range, coating-film intensity | strength and moisture resistance will fall.

4). Concentrating dye (B-4)
Examples of the condensing dye (B-4) used in the clear coating composition of the present invention include perylene pigments and derivatives thereof. The condensing dye is a kind of fluorescent dye, but the degree of fluorescence is strong because there is little overlap between the absorption wavelength region and the emission wavelength region, and the self-absorption of the dye hardly occurs. Moreover, it is positioned as a dye having very good weather resistance. Because of this performance, the dye is in a highly purified state.

  Examples of the condensing dye include Lumogen (registered trademark) F (manufactured by BASF) series YELLOW083, RED305, ORANGE24, VIOLET570, and the like. By using such a condensing dye, the resulting coating film has a high chroma color.

  The clear coating composition of the present invention contains components such as a pigment, an organic solvent, a curing catalyst, a surface adjusting agent, an anti-settling agent, an antifoaming agent, a viscosity adjusting agent, and a glittering material aligning agent as necessary. Also good. In addition, since the dye has low light resistance, it is preferable to blend an ultraviolet absorber or an antioxidant.

III. Multilayer coating film The multilayer coating film of the present invention has a base coating layer formed from the base coating composition and a clear coating layer formed on the base coating layer. The multilayer coating film of the present invention has good adhesion to a coated resin substrate and high chroma color.

  The multilayer coating film of the present invention comprises a step (1) of forming a base coating layer on a resin substrate with the base coating composition, and a dry-on on the base coating layer formed by the step (1). It is formed by the step (2) of forming a clear coating layer by the above-mentioned clear coating composition wet or wet on wet and the step (3) of curing the base coating layer and the clear coating layer. preferable.

  The coating method for forming the base coating layer and the clear coating layer is not particularly limited, and examples thereof include a spray coating method and an electrostatic coating method. Industrially, for example, an air electrostatic spray coating machine called “react gun” or a rotary atomizing electrostatic coating machine called “micro micro bell”, “micro bell”, “metallic bell” or the like is used. A method can be mentioned.

  In the said process (1), it is preferable to apply | coat so that the dry film thickness of a base coating film layer may be 5-40 micrometers. The dry film thickness is more preferably 10 to 25 μm in order to ensure a good appearance and workability of the coating film.

  After forming the base coating layer, a step (2) of forming a clear coating layer is performed. The dry film thickness of the clear coating layer is preferably 10 to 50 μm in order to ensure good appearance and workability of the coating.

  The multilayer coating film forming method of the present invention may be wet-on-wet coating or dry-on-wet coating method. That is, even if the clear coating layer is formed after heat-curing after forming the base coating layer by the step (1), the clear coating layer is formed without heating and curing. It may be cured at the same time.

  The baking temperature in the step (3) is preferably set to 110 to 130 ° C., for example, in consideration of quick curing and prevention of deformation of the resin base material coated with the multilayer coating film. Preferably, it is 120-130 degreeC. The baking time is usually 10 to 60 minutes, preferably 15 to 50 minutes, more preferably from the viewpoint of sufficient curing of the coating film, water resistance and solvent resistance of the resulting coating film, and energy cost of the coating process. 20 to 40 minutes. This baking time means the time during which the surface of the substrate actually keeps the target baking temperature. More specifically, the time until the target baking temperature is reached is not considered, and the target baking temperature is not considered. It means the time when the temperature has been maintained since reaching the temperature. Moreover, when forming a multilayer coating film by dry-on-wet, the baking conditions when hardening a base coating film layer may be the same conditions as the above.

  Examples of the heating device used for baking the uncured film of the paint include a drying furnace using a heating source such as hot air, electricity, gas, and infrared, and drying using two or more of these heating sources in combination. Use of an oven is preferable because the drying time is shortened.

  The resin base material to which the multilayer coating film forming method of the present invention can be applied is not particularly limited. For example, polyolefins such as polyethylene and polypropylene, polystyrene, ABS, vinyl chloride, polycarbonate, polyacetal, polyester, polyamide, Examples include polyurethane, PPO, polymethyl methacrylate, epoxy resin, phenol resin, and melamine resin. The base material may be subjected to a known pretreatment before coating, if necessary.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited to these examples.

(Preparation Example 1)
Preparation of acrylic resin (A-1) 2 parts by weight of propylene glycol monomethyl ether (PGME), butyl acetate 8 in a reaction vessel equipped with a stirrer, thermometer, reflux tube, dropping funnel, nitrogen introducing tube and thermostat-equipped heating device Then, 57 parts by weight, 8.57 parts by weight of toluene, and 5 parts by weight of an aromatic hydrocarbon solvent (“Sorvesso 100” manufactured by Exxon) were charged, and the internal temperature was raised to 110 ° C. while stirring.

  Subsequently, a mixed solution of 37.35 parts by weight of methyl methacrylate, 2.07 parts by weight of methacrylic acid, 44.08 parts by weight of n-butyl methacrylate, and 16.5 parts by weight of hydroxypropyl acrylate, 10 parts by weight of toluene and peroxide polymerization. An initiator solution consisting of 5 parts by weight of an initiator (“Kaya Ester O” manufactured by Nippon Kayaku Co., Ltd.) was separately added to each of two dropping funnels and dropped over 3 hours to initiate polymerization. During this time, the internal temperature was maintained at 110 ° C., and after completion of the dropwise addition, a solution consisting of 5 parts by weight of butyl acetate and 0.5 parts by weight of “Kayaester O” was continuously added while maintaining the internal temperature at 110 ° C. It dripped over time, superposition | polymerization was completed, and after cooling internal temperature to 80 degreeC, 40.76 weight part of toluene and 17 weight part of butyl acetate were prepared in order, and the acrylic resin (A-1) was obtained. The solid content of the acrylic resin was 50% by weight.

  Moreover, the weight average molecular weight was about 32,000 from the measurement by gel permeation chromatograph in terms of styrene. The hydroxyl value was 65 mgKOH / g, and the glass transition point was 5 ° C.

In addition, the solid content measuring method of the above-mentioned acrylic resin is to collect the acrylic resin (Xg) in an aluminum dish for non-volatile content measurement, and after drying at 110 ° C. for 3 hours, measure the residual solid content (Yg), Calculated:
Resin solid content (% by mass) = [(Y) / (X)] × 100.

(Measurement method of Tg)
As the Tg value, a differential scanning calorimeter (DSC) (thermal analyzer SSC5200 (manufactured by Seiko Denshi)) was used, and a value measured by the following steps was used. A step of raising the temperature from 20 ° C. to 150 ° C. at a rate of temperature increase of 10 ° C./min (step 1), a step of lowering the temperature from 150 ° C. to −50 ° C. at a rate of temperature drop of 10 ° C./min (step 2), This is a value obtained from the inflection point of the chart at the time of temperature increase in step 3 in the step of increasing the temperature from −50 ° C. to 150 ° C. at 10 ° C./min (step 3).

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

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

(Preparation Example 4)
Preparation of polyester polyol (B-1) In a 1 L separable flask equipped with a temperature controller, stirring blade, nitrogen inlet, Dean Stark trap, reflux tube, 135 g of trimethylolpropane, 114 g of 1,3-propanediol, sebacine 404 g of acid, 42 g of xylene and 1.2 g of p-toluenesulfonic acid were charged. The Dean Stark trap was filled with xylene up to the upper limit. Under a nitrogen stream, the temperature in the system is raised to 140 ° C. and held for 1 hour, further heated to 195 ° C., and the condensation reaction is continued for 5 hours, resulting in a resin acid value of 4 mg KOH / g (resin solid content). After confirming that it became, cooling was started. After cooling, butyl acetate was added to adjust the solid content to 70%. The hydroxyl value was 195 mgKOH / g.

(Preparation Example 5)
Preparation of acrylic resin (B-2) A 1 L separable flask equipped with a temperature controller, a stirring blade, a nitrogen inlet, and a reflux tube was charged with 300 g of butyl acetate and the temperature was adjusted to 120 ° C. There, 96.0 g of styrene, 61.3 g of 2-ethylhexyl acrylate, 130.0 g of 2-ethylhexyl methacrylate, 189.3 g of hydroxyethyl methacrylate, 3.4 g of methacrylic acid, 2,2′-azobis (2, A mixed solution of 36.0 g of 4-dimethylvaleronitrile) was added dropwise over 3 hours. After continuing the reaction for 1 hour, a mixed solution of 20.0 g of butyl acetate and 2.0 g of 2,2′-azobis (2,4-dimethylvaleronitrile) was dropped over 30 minutes, and then 1.5 hours. The temperature was kept at 120 ° C. When the molecular weight was measured by GPC, Mw = 6200 and Mn = 3200. The glass transition point was 20 ° C. and the hydroxyl value was 170 mgKOH / g. The solid content was 60%.

(Example 1)
1. Preparation of base coating composition Acrylic resin (A-1), chlorinated polyolefin resin (A-2), acrylic-modified chlorinated polyolefin resin (A-3) and polyisocyanate curing so that the total solid content is 23.4 g Dismodule TPLS2759 (manufactured by Sumitomo Bayer Urethane Co., Ltd.) was weighed as an agent (A-4), and while stirring with a disper, an aluminum paste, an anti-settling agent, a glittering material aligning agent, surface conditioning agents A, B and UVA were added thereto. They were weighed so as to have the solid contents shown in Table 1 and added in order, and finally weighed and added with a solvent in which toluene and butyl acetate were blended on a one-to-one basis so that the solvent contents were as shown in Table 1.

2. Preparation of Clear Coating Composition Polyester polyol (B-1) and acrylic resin (B-2) are weighed so that the total solid content is 100 g, and 38.8 g of methyl isobutyl ketone, 1.0 g of surface conditioner, 10 g of UV absorber, 2.0 g of antioxidant, 3.0 g of dibutyltin laurate (1.0% butyl acetate solution) and 19.4 g of butyl acetate were added and homogenized, and there was a curing agent H-2523 (Nippon Bee Chemical). To make clear paint. OH / NCO was adjusted to be 1/1. The paint before coating was prepared with a solvent mixed with 7 to 3 of butyl acetate and ethyl 3-ethoxypropionate so that the solvent content was 50% by weight.

3. Preparation of Multilayer Coating Film A base coating composition was spray-coated on a polypropylene (PP) substrate so that the dry film thickness was 16 μm and left at room temperature for 10 minutes. Next, the clear coating composition was spray-coated so that the dry film thickness was 25 μm, allowed to stand at room temperature for 10 minutes, and then baked at 80 ° C. for 45 minutes to obtain a multilayer coating film.

  The base coating composition was spray-coated on an acrylonitrile, butadiene and styrene copolymer synthetic resin (ABS) base material so that the dry film thickness was 16 μm, and left at room temperature for 10 minutes. Next, the clear coating composition was spray-coated so that the dry film thickness was 25 μm, left at room temperature for 10 minutes, and baked at 70 ° C. for 45 minutes to obtain a multilayer coating film.

(Examples 2 and 3 and Comparative Example 1-17)
A coating film was obtained in the same manner as in Example 1 except that the amount of each component of the base coating composition was changed as shown in Tables 1 and 2.

The coating films of Example 1-3 and Comparative Example 1-17 were evaluated based on the following criteria.
Paint condition The condition of the paint was visually observed:
○: No abnormality such as separation was observed in the paint. ×: The paint was separated.
Appearance of the coating film The appearance of the coating film was visually observed:
○: No abnormalities on the surface of the coating film such as blisters were observed X: Abnormality on the surface of the coating film such as blisters was observed.
Initial adhesion property It evaluated based on JIS-K-5600-5-6. Specifically, 100 bases having a size of 2 mm were formed on the coating film with a cutter knife, and a cellophane adhesive tape was completely adhered thereon, and one end of the tape was lifted and peeled upward. This peeling operation was carried out three times at the same location, and the number of square meshes in which the coating film was peeled off by 50% or more in the area of the first square was indicated by:
○: The number of square cells peeled off by 50% or more is 0 ×: The number of square cells peeled by 50% or more is 1 or more.
Water-resistant adhesion / water-resistant appearance The coating film is immersed in warm water at 40 ° C. for 240 hours, and then dried at room temperature for 1 hour. An eye tape peel test was performed:
Water-resistant adhesion ○: No peeling ×: Water-resistant appearance with slight peeling ○: No abnormality in appearance compared to before test ×: Abnormality in appearance compared to before testing It was.
The results are shown in Tables 1 and 2.

  From Table 1, the base coating film did not adhere to the PP substrate only with the acrylic resin (A-1) and the polyisocyanate curing agent (A-4) (Comparative Example 1). By adding the chlorinated polyolefin resin (A-2) to the acrylic resin (A-1) and the polyisocyanate curing agent (A-4), the base coating film becomes attached to the PP substrate. (A-2) has poor compatibility with other components, and the paint tends to separate. When the blending amount of the chlorinated polyolefin resin (A-2) is increased, the appearance of the coating film obtained is not good. (Comparative Example 3-5). By using the chlorinated polyolefin resin (A-2) and the acrylic-modified chlorinated polyolefin resin (A-3) in the ratio of Example 1, good adhesion to the PP base material of the base coating film is obtained, Compatibility with other components in the paint could also be ensured (Example 1, Comparative Example 5-7).

  From Table 1 and Table 2, the base coating composition of the formulation of Example 1-3 is in a better coating state than the base coating composition of Comparative Example 1-17, and Example 1-3 Compared with the coating film obtained from the base coating composition of Comparative Example 1-17, the coating film obtained using the base coating composition with the formulation of No. 1-17 was coated on a PP base material and an ABS base material. In any case, the coating film performance was excellent.

Example 4
As the base coating composition, the base coating composition (silver metallic dyeing) used in Example 1 was used.

  As the clear coating composition, one obtained by adding 1 part by weight of a red perylene pigment (LUMOGEN® F RED305) to the clear coating composition used in Example 1 was used.

  On the ABS base material pretreated with IPA wipe, the base paint was spray-coated so that the dry film thickness was 16 μm, and left at room temperature for 10 minutes. Next, the clear paint was spray-coated so that the dry film thickness was 25 μm, allowed to stand at room temperature for 10 minutes, and then baked at 70 ° C. for 45 minutes to obtain a multilayer coating film.

(Example 5)
Example 4 except that the base paint composition dyed red solid was used in place of the base paint composition aluminum paste instead of the colored CAB chip CB1 / 2 Red 3885 (AT) (manufactured by Taihei Chemicals). Similarly, a multilayer coating film was obtained.

(Example 6)
The base paint composition is replaced with CB1 / 2CR90 (ATHI) (produced by Taihei Chemical Products Co., Ltd.), the base paint composition dyed in white solid is used, and the red perylene pigment of the clear paint composition is replaced with yellow A multilayer coating film was obtained in the same manner as in Example 4 except that the perylene pigment (LUMOGEN (registered trademark) F YELLOW083) was used.

(Example 7)
The base coating composition used in Example 4 was spray-coated on a PP substrate pretreated with an IPA wipe so that the dry film thickness was 16 μm, and left at room temperature for 10 minutes. Next, the clear coating composition used in Example 4 was spray-coated so that the dry film thickness was 25 μm, left at room temperature for 10 minutes, and baked at 80 ° C. for 45 minutes to obtain a multilayer coating film.

(Example 8)
Using the base coating composition and the clear coating composition used in Example 5, coating was performed in the same manner as in Example 7 on a PP base material pretreated with an IPA wipe to obtain a multilayer coating film.

Example 9
Using the base coating composition and the clear coating composition used in Example 6, coating was performed in the same manner as in Example 7 on a PP substrate pretreated with an IPA wipe to obtain a multilayer coating film.

The coating film obtained in Example 4-9 was evaluated based on the criteria shown below. The results are shown in Table 3.
Total visual design The appearance of the coating film was visually observed.
Gloss 20 ° and 60 ° specular gloss was measured.
Initial adhesion The initial adhesion was measured as described above.
Moisture resistance test (appearance / adhesion)
The moisture resistance test was evaluated according to JIS-K-5600-7-12. Specifically, it is left for 240 hours in an atmosphere having a temperature of 50 ± 2 ° C. and a humidity of 98 ± 2%, and the surface of the coating film is observed and a substrate adhesion test is performed within 1 hour. In the substrate adhesion test, 100 substrate pieces of 2 mm are formed on the coating film with a cutter knife, and the cellophane adhesive tape is completely adhered thereon, and one end of the tape is lifted and peeled upward. This peeling operation is carried out three times at the same location, and is indicated by the number of square squares in which the coating film is peeled off by 50% or more in the area of the first square:
Appearance ○: No coating surface abnormality such as whitening or blistering was observed ×: Adhesion in which coating surface abnormality such as whitening or blistering was observed ○: 0 peeling sites ×: 1 or more peeling Was seen.

  From Table 3, the base coating composition of the present invention is a base coating composition dyed red solid and white solid in addition to the base coating composition dyed silver metallic using an aluminum paste (Examples 4 and 7). Examples 5, 6, 8, and 9) could also be used. In addition, even when a perylene pigment was blended in the clear coating composition, the coating appearance such as gloss of the resulting multilayer coating film and the coating performance such as initial adhesion and moisture resistance were good.

Claims (2)

Acrylic resin (A-1) having a hydroxyl value of 40 to 120 mgKOH / g, chlorinated polyolefin resin (A-2), acrylic-modified chlorinated polyolefin resin (A-3), and a polyisocyanate compound blocked with a blocking agent A base coating composition containing a polyisocyanate curing agent (A-4),
The amount of the acrylic resin (A-1) is 40 to 65% by weight based on the total weight of (A-1), (A-2), (A-3) and (A-4), and chlorinated. A base coating composition in which the amount of the polyolefin resin (A-2) is 5 to 18% by weight and the amount of the acrylic-modified chlorinated polyolefin resin (A-3) is 20 to 30% by weight. A multilayer coating film having a base coating layer formed from the base coating composition of claim 1 and a clear coating layer formed on the base coating layer,
A clear coating layer is obtained by polymerization of a raw material composition comprising a trifunctional or higher functional polyol, sebacic acid and diol, and has a hydroxyl value of 140 to 240 mgKOH / g, a polyester polyol (B-1), and a hydroxyl value of 120 to 120. Formed from a clear coating composition containing an acrylic resin (B-2) having a glass transition point of 0 to 40 ° C., a polyisocyanate curing agent (B-3), and a condensing dye (B-4) having a glass transition point of 220 mgKOH / g Multi-layer coating.