Active energy ray-curable undercoating composition for automobile-light reflection members to be metallic-mirror-surfaced, and method for producing coated article

Abstract

The purpose of the present invention is to provide: an active energy ray-curable undercoating composition for automobile-light reflection members to be metallic-mirror-surfaced, the undercoating composition being curable with a light source device which emits active energy rays derived from a light-emitting diode; and an automobile-light reflection member to be metallic-mirror-surfaced, the reflection member having been coated with the undercoating composition.　The active energy ray-curable undercoating composition for automobile-light reflection members to be metallic-mirror-surfaced is characterized by comprising given amounts of: a given alkyd resin; a given mixture of dipentaerythritol hexa- and penta(meth)acrylates; a bi- or trifunctional (meth)acrylate having a cyclic structure in the molecule; a given acrylic resin; a hydrogen abstraction type photopolymerization initiator; an α-aminoalkylphenone-based photopolymerization initiator; an amine synergist; and an organic solvent.

Description

Active energy ray curable undercoat paint composition for automobile lamp reflecting members with a metallic mirror finish and method for producing a coated article

[0001] The present invention relates to an active energy ray curable undercoat paint composition for automobile lamp reflecting members with a metallic mirror finish having curability by an active energy ray generation light source device derived from a diode that emits ultraviolet rays with a peak wavelength of 200 to 405 nm (hereinafter referred to as "UV-LED"), and a method for producing a coated article.

[0002] Reflecting members such as automobile lamp reflectors are often used with a mirror finish on the surface of fiber reinforced plastics (hereinafter referred to as "FRP") such as polyphenylene sulfide (PPS), polyphenylene ether (PPE), polybutylene terephthalate (PBT) / polyethylene terephthalate (PET) alloy resin, heat-resistant polycarbonate (heat-resistant PC), acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylic resin (PMMA), etc., which are reinforced with fillers such as glass fibers, from the viewpoints of being lightweight and having excellent corrosion resistance, heat resistance, and impact resistance. In recent years, in automobile lamps, light-emitting diodes (hereinafter referred to as "LED") bulbs with little heat generation have become widespread, and the number of heat-resistant plastics that do not contain reinforcing fibers with relaxed heat resistance has also increased. (Hereinafter referred to as "heat-resistant plastic").

[0003] As a method for forming a mirror finish on FRP and heat-resistant plastic, a method of vapor deposition or sputtering a metal such as aluminum is common. However, in FRP, it is difficult to obtain a smooth material surface due to fiber segregation, entrapped air bubbles, etc., and in heat-resistant plastic, it is similarly difficult to obtain a smooth material surface because of its low melt fluidity during molding processing. Therefore, a method of performing mirror finishing after coating and curing an undercoat paint is adopted.

[0004] The undercoat paint used for this application requires heat durability against heat-generating members such as bulbs, control boards for sensors, snow melting devices, engines, drive batteries, regenerative brakes, and sunlight, and also requires heat resistance against a heat source for melting a metal and molten metal that collides and adheres to the coating film at a high temperature in a vacuum vapor deposition or sputtering process. Conventionally, an active energy ray curable paint composition having excellent coating film hardness and the like has been used.

[0005] The lenses of automotive lights are made of transparent or colored transparent polycarbonate (red, yellow, etc.) which offers excellent transparency, impact resistance, heat resistance, dimensional stability, and self-extinguishing properties. For reflective components, the selection of polycarbonate-based materials is increasing from the perspective of material recovery and recycling. Polycarbonate-based materials include polycarbonate, heat-resistant polycarbonate, and polycarbonate-ABS alloy resins. Because polycarbonate-based materials have high melt viscosity and it is difficult to obtain a smooth surface, metallization such as aluminum vapor deposition has traditionally been performed after coating with an active energy ray-curable primer.

[0006] Polycarbonate materials are prone to outgassing due to their composition, manufacturing process, and water absorption properties. This can lead to problems such as air bubbles accumulating between the material and a poorly permeable mirrored metal film, resulting in loss of mirror-like surface and reduced reflective function. The active energy ray curable primer composition used for polycarbonate materials was designed to have sufficient film strength to suppress air bubbles by selecting raw materials that adhere well to polycarbonate materials and adapting the photopolymerization initiator to a mercury lamp. This is achieved by improving crosslinking properties through the combined emission of strong ultraviolet rays and infrared rays.

[0007] The above-mentioned active energy ray-curable primers are typically cured with industrial mercury lamps. However, mercury is subject to restrictions or prohibitions such as the RoHS Directive (Restriction of the use of certain hazardous substances in electrical and electronic equipment), and regulations concerning the use of mercury are being added and strengthened year by year.

[0008] In recent years, UV-LED elements that do not contain mercury and emit light in the ultraviolet wavelength range (wavelengths of 200-405 nm) have become commercially available, making it possible to reproduce the ultraviolet emission lines of mercury lamps using UV-LEDs.

[0009] UV-LEDs emit no light other than ultraviolet light, so they have no thermal effect on thermoplastic materials such as plastics that are irradiated, and they are easy to turn on and off, resulting in superior overall energy consumption. On the other hand, unlike mercury lamps, which emit light at high density throughout the entire tube and allow for dimming adjustments such as focus using a reflector, UV-LED lamps emit light from light-emitting elements scattered on a substrate, resulting in low light density and limited dimming adjustment range because the light emission direction is only in one direction on the substrate.

[0010] When printing on sheet-fed substrates such as films using UV inks and irradiating them with a UV-LED lamp, a sufficient dose of active energy can be obtained by bringing the UV-LED lamp close to the substrate wrapped around the roll. However, reflector components such as automotive lighting fixtures are three-dimensional structures with various shapes depending on the vehicle model, requiring irradiation with active energy rays from a distance from the lamp. Curing them using UV-LED lamps, where adjusting the focusing distance is difficult, has been extremely challenging. In addition, automotive lighting fixtures are safety components that are always installed on the front, rear, left, right, sides with indicator lights, and door mirrors, resulting in very high production volumes. Simply replacing mercury lamps with UV-LED lamps would not allow for maintaining the current level of productivity. Therefore, in order to maintain the current high productivity without using mercury lamps, just as the printing industry has developed and established UV inks specifically for UV-LED curing, there is a need to design active energy ray curable primer coating compositions for automotive lighting fixture reflective components specifically for UV-LED curing.

[0011] In addition, for polycarbonate-based materials used in automotive lighting reflectors, there is a need for UV-LED curable active energy ray curable primer coating compositions and methods for producing them that suppress outgassing bubbles.

[0012] Patent Document 1 does not assume the formation of a coating film by curing with UV-LEDs.

[0013] Patent documents 2 and 3 do not contain photopolymerization initiators and amine synergists optimized for curing with UV-LED lamps, resulting in slow curing speeds that are unsuitable for practical use.

[0014] Japanese Patent Publication No. WO1995 / 032250, Japanese Patent Publication No. 2022-104104, Japanese Patent Publication No. 2022-104109

[0015] The present invention aims to provide an active energy ray primer for automotive lighting reflective members that can be efficiently cured by active energy rays emitted from mercury-free UV-LED lamps to create a metallic mirror surface, by improving upon the primer compositions described in Patent Documents 1, 2, and 3, and to provide a highly productive method for manufacturing painted articles.

[0016] The present invention has been made to solve the above problems and provides the following embodiments. [Embodiment 1] Component (A): Alkyd resin component (B): Mixture component of dipentaerythritol hexa and penta(meth)acrylate (C): Two- to three-functional (meth)acrylate component having a cyclic structure in the molecule (D): Acrylic resin component (E): Hydrogen abstraction type photopolymerization initiator component (F): α-aminoalkylphenone-based photopolymerization initiator component (G): Amine synergist component (H): Contains an organic solvent as an essential component, Component (A) has an oil length of 35-45%, an acid value of 0.01-10 mgKOH / g, a hydroxyl value of 120-150 mgKOH / g, and a weight-average molecular weight of 80,000-150,000; Component (B) has a hydroxyl value of 50 mgKOH / g or less; Component (D) has a glass transition temperature of 10-70°C, an acid value of 2-10 mgKOH / g, a hydroxyl value of 40-120 mgKOH / g, and a weight-average molecular weight of 4,000-20,000; and the solid content of component (A) is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total solid content of components (A), (B), (C), and (D), and the solid content of component (B) is 30 parts by mass or more and 50 parts by mass or less. The active energy ray-curable primer paint composition for automotive lamp reflective members to be given a metallic mirror surface, characterized in that the solid content of component (C) is 10 parts by mass or more and 20 parts by mass or less, the solid content of component (D) is 20 parts by mass or more and 30 parts by mass or less, the content of component (E) is 1 part by mass or more and 10 parts by mass or less, the content of component (F) is 1 part by mass or more and 10 parts by mass or less, and the content of component (G) is 3 parts by mass or more and 15 parts by mass or less. [Aspect 2] The paint composition according to Aspect 1 further comprises component (I): amino resin, and the content of component (I) is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total solid content of components (A), components (B), components (C), and components (D), as described in Aspect 1.[Aspect 3] The active energy ray-curable primer composition for automotive lamp reflective members to be given a metallic mirror finish, according to aspect 1 or 2, wherein component (A) is modified with at least one selected from the group consisting of tall oil fatty acids, soybean oil, safflower oil, castor oil, and mixtures thereof, and has an iodine value of 80 to 160 when alone or when two or more fatty acids and oils are mixed. [Aspect 4] The active energy ray-curable primer composition for automotive lamp reflective members to be given a metallic mirror finish, according to aspect 1 or 2, wherein component (C) has a bisphenol A structure, a bisphenol F structure, a bisphenol AF structure, a 1,3-dioxane structure, a tricyclodecane structure, or a triazine ring. [Aspect 5] A method for manufacturing a painted article, characterized in that an active energy ray-curable primer paint composition for automotive lamp reflective members that provides a metallic mirror surface as described in Aspect 1 or 2 is applied to a workpiece which is an automotive lamp reflective member, an active energy ray is irradiated after solvent removal to form a cured coating film, the film thickness of which is 5 μm or more and 50 μm or less, and in subsequent steps, a metallic mirror surface is obtained on the surface of the workpiece by metal deposition, metal sputtering, silver mirror reaction and mirror surface forming coating.

[0017] The present invention provides an active energy ray curable primer coating composition that hardens with active energy rays emitted from a UV-LED lamp, and a method for manufacturing a coated article. The composition contains the following essential components: (A) an alkyd resin component, (B) a mixture of dipentaerythritol hexa and penta(meth)acrylate, (C) a 2-3 functional (meth)acrylate component having a cyclic structure in the molecule, (D) an acrylic resin component, (E) a hydrogen abstraction type photopolymerization initiator component, (F) an α-aminoalkylphenone-based photopolymerization initiator component, (G) an amine synergist component, and (H) an organic solvent. By including these as essential components, the composition hardens with a UV-LED light source and can obtain the necessary and sufficient properties for use as an automotive lighting reflective material, contributing to energy saving and environmental protection.

[0018] Component (A): Alkyd Resin Component (A) of the present invention is an alkyd resin modified with fatty acids or oils and fats, and is formulated to improve adhesion to materials and adhesion to metals used in mirror finishing. Fatty acids are monovalent carboxylic acids having a carboxyl group in the hydrocarbon chain, and oils and fats are ester compounds of fatty acids and glycerol. Component (A) can be obtained by using a fatty acid or oil as a modifying agent in addition to a polyhydric alcohol and a polybasic acid or its acid anhydride. Component (A) is composed of 15 to 25 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). Component (A) must have an oil length of 35 to 45%, an acid value of 0.01 to 10 mg KOH / g, a hydroxyl value of 120 to 150 mg KOH / g, and a weight-average molecular weight of 80,000 to 150,000.

[0019] The polyhydric alcohol used in component (A) is not particularly limited and includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,2-hexylene glycol, 1,6-hexanediol, heptanediol, cyclohexanediol, 2-butene-1,4-diol, 3-cyclohexene-1,1-dimethanol, 4-methyl-3-cyclohexene-1,1-dimethanol, 3-methylene-1,5-pentanediol, (2-hydroxyethoxy)-1-propanol, 4-(2-hydroxyethoxy)-1-butanol, 5-(2-hydroxyethoxy)-pentanol, 3-(2-hydroxypropoxy)-1-butanol, 4-(2-hydroxypropoxy)-1-butanol, 5-(2-hydroxypropoxy)-1-pentanol, 1-(2-hydroxyethoxy)-2-butanol, 1-(2-hydroxyethoxy)-2-pentanol, hydrogenated bisphenol A, glycerin, diglycerin, polycaprolactone, 1,2,6 -Hexantriol, trimethylolpropane, trimethylolethane, pentanetriol, trishydroxymethylaminomethane, 3-(2-hydroxyethoxy)-1,2-propanediol, 3-(2-hydroxypropoxy)-1,2-propanediol, 6-(2-hydroxyethoxy)-1,2-hexanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol hydroxypivalate, spiroglycol, 2,2-bis(4-hydroxyethoxyphenyl)propane, 2,Examples of polyols include 2-bis(4-hydroxypropyloxyphenyl)propane, pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolpropane, ditrimethylolpropane, tritrimethylolpropane, trishydroxyethyl isocyanurate, di(2-hydroxyethyl)-1-acetoxyethyl isocyanurate, di(2-hydroxyethyl)-2-acetoxyethyl isocyanurate, mannitol, glucose, and others. Furthermore, examples include alkylene oxide-modified or lactone-modified polyols obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, γ-caprolactone, etc., to these polyols, as well as polyester polyols and polyether polyols having terminal hydroxyl groups obtained by condensing these polyols with polybasic acids or their acid anhydrides. In the present invention, one or more of these can be used in combination.

[0020] The polybasic acid or its acid anhydride used in component (A) is not particularly limited, and examples include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, methylcyclohexentricarboxylic acid, adipic acid, sebacic acid, azelaic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hymic acid, succinic acid, dodecinyl succinic acid, methylglutaric acid, pimelic acid, malonic acid, maleic acid, fumaric acid, chloromaleic acid, dichloromaleic acid, citraconic acid, mesaconic acid, itaconic acid, tetrahydrophthalic acid, carbic acid, hetic acid, aconitic acid, glutaconic acid, and their acid anhydrides. In the present invention, one or more of these can be used in combination.

[0021] Component (A) is present in an amount of 15 to 25 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 15 parts by mass, material adhesion, heat resistance, thermal cycling properties, appearance of the vapor-deposited aluminum, and adhesion will decrease. If the amount exceeds 25 parts by mass, UV-LED curability, paint appearance, moisture resistance, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease.

[0022] The fatty acids and oils used in component (A) are not particularly limited and may be any of non-drying oils, semi-drying oils, or drying oils, but preferably have an iodine value of 80 to 160. Examples of such oils include those selected from the group consisting of tall oil fatty acids, soybean oil, safflower oil, castor oil, and mixtures of fatty acids and oils. The iodine value is the value obtained by converting the amount of halogen that binds when a halogen is reacted with 100 g of the sample into grams of iodine, and was measured in accordance with JIS K 0070. If the iodine value is less than 80, the compatibility with components (B), (C), and (D) decreases, and the curability, appearance, water resistance, heat resistance, and appearance of the vapor-deposited aluminum deteriorate. If the iodine value exceeds 160, the amount of drying oil components increases, and the storage stability of the paint composition decreases.

[0023] Component (A) used in the present invention must have an acid value in the range of 0.01 to 10 mg KOH / g. The acid value is the number of mg of potassium hydroxide required to neutralize the free fatty acids, resin acids, etc. contained in 1 g of the sample, and was measured in accordance with JIS K 0070. If the acid value is less than 0.01 mg KOH / g, the reaction will take a long time to reach almost the reaction endpoint, and productivity will decrease. If it is greater than 10 mg KOH / g, the storage stability of the paint composition will decrease. The acid value is preferably 1 to 7 mg KOH / g, more preferably 2 to 5 mg KOH / g.

[0024] Component (A) must have a weight-average molecular weight of 80,000 to 150,000. The weight-average molecular weight was measured by gel permeation chromatography. The weight-average molecular weights used herein are values ​​measured by gel permeation chromatography using an HLC-8200 manufactured by Tosoh Corporation. The measurement conditions were as follows: Column: TSgel Super Multipore HZ-M 3-column; Developing solvent: Tetrahydrofuran column inlet; Oven temperature: 40°C; Flow rate: 0.35 ml; Detector: RI standard polystyrene, PS oligomer kit manufactured by Tosoh Corporation

[0025] If the weight-average molecular weight is less than 80,000, the appearance of the coating film, storage stability, and the appearance of the vapor-deposited aluminum deteriorate. If it exceeds 150,000, it becomes difficult to obtain a smooth coating surface, and the appearance of the coating film, storage stability, and the appearance of the vapor-deposited aluminum deteriorate. The weight-average molecular weight is preferably 90,000 to 130,000, and more preferably 100,000 to 120,000.

[0026] The above component (A) must have a hydroxyl value of 120 to 150 mg KOH / g. The hydroxyl value is the number of mg of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl groups after acetylating 1 g of the sample, and was measured in accordance with JIS K 0070. If the hydroxyl value is less than 120 mg KOH / g, the adhesion to the material and storage stability will decrease, and if it is 150 mg KOH / g or more, the water resistance and moisture resistance will decrease.

[0027] The oil length of component (A) mentioned above must be 35-45%. "Oil length" refers to the value expressed based on the weight percentage of fatty acids and oils. If the oil length is less than 35%, the appearance of the paint, the appearance of the vapor-deposited aluminum, and adhesion will be reduced. If the oil length exceeds 45%, dripping is likely to occur after painting, and the appearance of the paint, the heat resistance, the appearance of the vapor-deposited aluminum, and the heat resistance will be reduced.

[0028] Component (B): A mixture of dipentaerythritol hexa and penta(meth)acrylate. Component (B) is obtained from the dehydration reaction of dipentaerythritol and acrylic acid, and is a polyfunctional (meth)acrylate having 5 to 6 (meth)acryloyl groups. It polymerizes and hardens upon ultraviolet irradiation and the action of a photopolymerization initiator to form a primer film.

[0029] Component (B) is composed of 30 to 50 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 30 parts by mass, UV-LED curability, water resistance, moisture resistance, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease. If it exceeds 50 parts by mass, material adhesion, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease. Therefore, the amount is limited to the above range.

[0030] The hydroxyl value of component (B) is between 10 mg KOH / g and 50 mg KOH / g. If the hydroxyl value is less than 10 mg KOH / g, the reaction will proceed almost to the endpoint, requiring a long time and the addition of a large amount of dehydration catalyst and polymerization inhibitor, which is economically disadvantageous. If the hydroxyl value is 50 mg KOH / g or higher, the amount of penta(meth)acrylate increases, resulting in a decrease in UV-LED curability, appearance, water resistance, moisture resistance, and heat resistance.

[0031] Component (C): Component (C) is a bifunctional (meth)acrylate having a cyclic structure within its molecule. It has the effect of improving compatibility with components (A), (B), and (D), improving storage stability in the paint solution, and suppressing intralayer fracture within the film during adhesion tests of the cured coating film. If the molecule does not have a cyclic structure, intralayer fracture occurs, reducing heat resistance, thermal cycling properties, and the heat resistance of the vapor-deposited aluminum.

[0032] Component (C) is composed of 10 to 20 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 10 parts by mass, intralayer fracture occurs within the film during adhesion tests, reducing the storage stability of the coating composition. If the amount exceeds 20 parts by mass, UV-LED curability, coating appearance, moisture resistance, heat resistance, thermal cycling properties, appearance of vapor-deposited aluminum, and heat resistance decrease.

[0033] Examples include ethylene oxide-modified bisphenol A di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and isocyanurate ethylene oxide-modified di(meth)acrylate.

[0034] Examples of commercially available products include Ebecryl 150, Ebecryl 130, IRR-214K (manufactured by Daicel Ornex Co., Ltd.), Aronix M-208, Aronix M-211B, Aronix M-215, Aronix M-315 (manufactured by Toagosei Co., Ltd.), NK Ester BPE-80N, NK Ester BPE-100, NK Ester BPE-200, and NK Ester DCP (manufactured by Shin Nakamura Chemical Co., Ltd.).

[0035] Component (D): Component (D) is an acrylic resin that improves adhesion to polycarbonate-based materials, suppresses bubbles from outgassing, and improves the heat-resistant appearance of vapor-deposited aluminum.

[0036] Component (D) is composed of 20 to 30 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 20 parts by mass, the adhesion to the material, water resistance, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease. If the amount exceeds 30 parts by mass, the UV-LED curability, moisture resistance, thermal cycling properties, appearance of the vapor-deposited aluminum, and heat resistance will decrease.

[0037] Component (D) has an acid value of 2 to 10 mg KOH / g, a glass transition temperature of 10 to 70°C, a hydroxyl value of 40 to 120 mg KOH / g, and a weight-average molecular weight of 4,000 to 20,000.

[0038] If the acid value of component (D) is less than 2 mg KOH / g, the adhesion of the vapor-deposited aluminum decreases, and if it is 10 mg KOH / g or more, the water resistance, moisture resistance, and storage stability decrease.

[0039] If the glass transition temperature of component (D) is below 10°C, the moisture resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease. If it is above 70°C, the appearance of the coating, thermal cycling properties, and appearance of the vapor-deposited aluminum will decrease.

[0040] If the hydroxyl value of component (D) is less than 40 mg KOH / g, material adhesion and water resistance will decrease, and if it is 120 mg KOH / g or more, water resistance and moisture resistance will decrease.

[0041] When the weight average molecular weight is less than 4,000, the heat resistance, thermal cycle resistance, appearance of vapor-deposited aluminum, and heat resistance decrease. When it is 20,000 or more, the coating appearance and appearance of vapor-deposited aluminum decrease.

[0042] Component (D) can be prepared by polymerization using one or more polymerizable monomers selected from polymerizable monomers having an acid group, polymerizable monomers having a hydroxyl group, and other polymerizable monomers.

[0043] Examples of the polymerizable monomer having an acid group include polymerizable monomers having a carboxyl group, a sulfonic acid group, etc. Examples of those having a carboxyl group include (meth)acrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, maleic anhydride, fumaric acid, etc. Examples of the polymerizable monomer having a sulfonic acid group include t-butylacrylamidosulfonic acid, etc. When using a polymerizable monomer having an acidic group, it is preferable that a part of the acidic group is a carboxyl group.

[0044] Examples of the polymerizable monomer having a hydroxyl group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxymethyl methacrylate, allyl alcohol, an adduct of hydroxyethyl (meth)methacrylate and ε-caprolactone, etc.

[0045] As other polymerizable monomers, for example, (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tridecyl methacrylate; addition reaction products of an oxirane compound containing an alkyl group having 3 or more carbon atoms and acrylic acid or methacrylic acid; styrene, α-methylstyrene, о-methylstyrene, m-methylstyrene, p-methylstyrene, p-t-butylstyrene, benzyl (meth)acrylate, itaconic acid esters (such as dimethyl itaconate), maleic acid esters (such as dimethyl maleate), fumaric acid esters (such as dimethyl fumarate), acrylonitrile, methacrylonitrile, methyl isopropenyl ketone, vinyl acetate, Veova monomer (manufactured by Shell Chemical Company, trade name), vinyl propionate, vinyl pivalate, ethylene, propylene, butadiene, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, acrylamide, vinyl pyridine, etc.; glycidyl group-containing unsaturated monomers such as glycidyl (meth)acrylate, and addition reaction products of these glycidyl group-containing unsaturated monomers and fatty acids; isocyanate group-containing unsaturated monomers such as m-isopropenyl-α,α-dimethylbenzyl isocyanate, isocyanatoethyl acrylate; and the like can be mentioned.

[0046] The method for preparing component (D) is not particularly limited, and for example, it can be carried out by solution polymerization such as ordinary radical polymerization. When preparing component (D) by radical polymerization, it is preferable to use a radical polymerization initiator.

[0047] Examples of radical polymerization initiators include azo-based initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis(2,4-dimethylvaleronitrile); and hydrogen peroxide derivative initiators such as benzoyl peroxide, lauryl peroxide, t-butyl peroctoate, and t-butyl peroxy-2-ethylhexanoate. The amount of these initiators used is preferably 0.2 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the total polymerizable monomer. The polymerization conditions in the radical polymerization reaction can be carried out by general polymerization conditions known to those skilled in the art.

[0048] Component (D) may optionally have an active energy ray-curable unsaturated group. Examples of active energy ray-curable unsaturated groups include vinyl groups, alkenes such as allyl groups, acryloyl groups, and methacryloyl groups. Having such an active energy ray-curable unsaturated group in component (D) improves the compatibility between component (B) and component (C), improves the stability of the coating composition, and results in better uniformity of the resulting coating film, among other advantages.

[0049] When component (D) has active energy ray-curable unsaturated groups, it is preferable that the number of active energy ray-curable unsaturated groups is an average of 1 to 3 per molecule of component (D). Having the number of active energy ray-curable unsaturated groups within this range is preferable because it allows for a good balance between the above advantages and the physical properties of the resulting coating, such as impact resistance.

[0050] Acrylic resins having active energy ray-curable unsaturated groups can be produced, for example, by copolymerizing a monomer mixture containing a glycidyl group-containing unsaturated monomer, and then adding a polymerizable monomer having an acidic group, such as (meth)acrylic acid, or by copolymerizing a monomer mixture containing a polymerizable monomer having an acidic group, and then adding a glycidyl group-containing unsaturated monomer, such as glycidyl (meth)acrylate.

[0051] Component (E): Hydrogen Abstraction Type Photopolymerization Initiator The active energy ray curable primer coating composition of the present invention is formulated with component (E) to impart active energy ray curability. Component (E) is a hydrogen abstraction type photopolymerization initiator that abstracts hydrogen from the resin components of materials such as FRP and heat-resistant plastics, and has the effect of improving adhesion between the coating film and the material through crosslinking. Furthermore, in combination with the α-aminoalkylphenone-based photopolymerization initiator of component (F) and the amine synergist of component (G), it has the effect of promoting the crosslinking reaction.

[0052] Component (E) is present in an amount of 1 to 10 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 1 part by mass, UV-LED curability, paint appearance, interlayer fracture adhesion, water resistance, moisture resistance, heat resistance, thermal cycling properties, appearance of vapor-deposited aluminum, and heat resistance will decrease. If the amount exceeds 10 parts by mass, no particular problems will occur, but it will be economically disadvantageous.

[0053] For example, benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 2-(1,1'-biphenyl-4-yl)carbonylbenzoate-2-ethylhexyl, 4-benzoyl-4'-methyldiphenyl sulfide, 2-benzoylmethylbenzoate, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one, polyethylene glycol bis(para-dimethylaminobenzoate) (Pollutant), methyl benzoyl formate, thioxanthone, 2,4-diethylthioxanthene-9-one, 2-isopropylthioxanthone, polyethylene glycol bis(9-oxo-9H-thioxanthenylooxy)acetate, 3-benzoyl-7-(N,N-diethylamino)coumarin, 7-methoxy-3-(4-tert-butylbenzoyl)coumarin, 3-(4-tert-butylbenzoyl)benzo[f]coumarin, 7-ethylthio-3-benzoylcoumarin, At least one selected from the group consisting of 3-(4-tert-butylbenzoyl)-5,7-dimethoxycoumarin and 7-(sec-butylthio)-3-benzoylcoumarin, particularly thioxanthone, 2,4-diethylthioxanthene-9-one, 2-isopropylthioxanthone, 3-benzoyl-7-(N,N-diethylamino)coumarin, 7-methoxy-3-(4-tert-butylbenzoyl)coumarin, and 3-(4-tert-butylbenzoyl) Benzo[f]coumarin, 7-ethylthio-3-benzoylcoumarin, 3-(4-tert-butylbenzoyl)-5,7-dimethoxycoumarin, and 7-(sec-butylthio)-3-benzoylcoumarin have absorption bands on the longer wavelength side of the ultraviolet region and are highly effective in effectively utilizing the active energy rays from UV-LEDs with peak wavelengths of 350-405 nm. They are particularly effective when the coating film thickness is thick or when the amount of active energy radiation from UV-LEDs is low on three-dimensional coated objects.

[0054] Examples of commercially available products include Omnirad BP FLAKE, Omnirad ITX, Omnirad DETX, Omnipol TX, EsaCure 3644 (manufactured by IGM Resins), and 2-EAQ (manufactured by Yamamoto Chemical Co., Ltd.). In the present invention, one or more of these can be used in combination.

[0055] Component (F): α-aminoalkylphenone-based photopolymerization initiator The active energy ray curable primer paint composition of the present invention is further formulated with component (F) to impart active energy ray curability. Component (F) is an α-aminoalkylphenone-based photopolymerization initiator, which has particularly good compatibility with the active energy rays of UV-LEDs having a peak wavelength of 350 to 420 nm, and in combination with components (E) and (G), has the effect of promoting the crosslinking reaction.

[0056] Component (F) is present in an amount of 1 to 10 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 1 part by mass, the UV-LED curability, paint appearance, water resistance, moisture resistance, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will decrease. If it exceeds 10 parts by mass, no particular problems will occur, but it will be economically disadvantageous.

[0057] Examples include 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)butan-1-one, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, and polyethylene glycol di(β-4-(2-dimethylamino-2-benzyl)butaonylphenyl)piperazine)propionate.

[0058] Examples of commercially available products include Omnirad 907, Omnirad 369, Omnirad 379, and Omnipol 910. In the present invention, one or more of these can be used in combination.

[0059] Component (G): Amine Synergist The active energy ray curable primer paint composition of the present invention is further enriched with component (G) to impart active energy ray curability. Component (G) serves as a hydrogen source for the hydrogen abstraction type photopolymerization initiator of component (E), and the radical polymerization reaction initiated from component (G) from which hydrogen has been abstracted effectively utilizes active energy rays from UV-LEDs, resulting in improved curability and adhesion.

[0060] Component (G) is composed of 3 to 15 parts by mass per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount is less than 3 parts by mass, UV-LED curability, paint appearance, water resistance, moisture resistance, heat resistance, thermal cycling properties, appearance of vapor-deposited aluminum, and heat resistance will decrease. If it exceeds 15 parts by mass, water resistance and moisture resistance will decrease, which is also economically disadvantageous.

[0061] Examples include 2-ethylhexyl-4-(dimethylamino)benzoate, ethyl-4-(dimethylamino)benzoate, poly(ethylene glycol)bis(para-dimethylaminobenzoate), N-methyldiethanolamine, N,N-dimethylaminoethanol, and N,N-dibutylaminoethanol.

[0062] Examples of commercially available products include Omnirad EHA, Omnirad EDB, Omnirad ASA, EsaCure A198 (manufactured by IGM Resins), Amino Alcohol MDA, Amino Alcohol 2Mabs, and Amino Alcohol 2B (manufactured by Nippon Emulsifier Co., Ltd.). In the present invention, one or more of these can be used in combination.

[0063] Component (H): The organic solvent component (H) is a solvent commonly used in paints and has the effect of diluting the primer paint composition of the present invention to make it easier to apply. Component (H) is not particularly limited, but examples include alcohol-based solvents, ketone-based solvents, ester-based solvents, petroleum-based solvents, aromatic solvents, etc., and one or more of these can be used in combination. The amount of the above solvent can be increased or decreased as needed.

[0064] Component (I): Amino resin. By adding component (I) to the active energy ray curable primer coating composition of the present invention, the thermal cycling properties can be improved.

[0065] Component (I) is present in an amount of 10 parts by mass or less per 100 parts by mass of the total solid content of components (A), (B), (C), and (D). If the amount exceeds 10 parts by mass, the paint appearance, heat resistance, thermal cycling properties, and heat resistance of the vapor-deposited aluminum will deteriorate.

[0066] Examples include methylated melamine, ethylated melamine, n-butylated melamine, isobutylated melamine, methylated benzoguanamine, melamine (meth)acrylate, ethylated benzoguanamine, n-butylated benzoguanamine, isobutylated benzoguanamine, and benzoguanamine (meth)acrylate.

[0067] Examples of commercially available products include Yuban 21R, Yuban 128, Yuban 228, Yuban 62, Yuban 169 (manufactured by Mitsui Chemicals), Nikarac MS-11, Nikarac MX-035 (manufactured by Nippon Carbide Industries), BMA-222, XMA-220, BMA-222, XMA-224 (manufactured by Bomber Specialties). In the present invention, one or more of these can be used in combination.

[0068] Other Components: In addition to the above components, the active energy ray curable primer paint composition of the present invention may optionally contain surface modifiers such as silicone-based additives, fluorine-based additives, acrylic-based additives, and cellulose-based additives. These additives have the effect of preventing repelling when applied to the substrate by lowering the surface tension and improving wettability. The cellulose-based additives have the effect of improving film formation during application, preventing repelling when applied to the substrate, and smoothing the surface.

[0069] The active energy ray curable primer paint composition of the present invention may further contain, if necessary, additives commonly used in paint compositions, such as viscosity modifiers, defoamers, ultraviolet absorbers, light stabilizers, antioxidants, storage stabilizers, adhesion promoters, organic or inorganic pigments, organic beads, inorganic beads, and mixtures thereof. These additives may be included in amounts commonly used by those skilled in the art.

[0070] The above additives are not particularly limited and include, for example, viscosity modifiers such as amide wax, electrostatic additives to improve paint adhesion, and rust inhibitors for vapor-deposited metals. UV absorbers are not particularly limited and include benzophenone-based, benzotriazole-based, and triazine-based UV absorbers. Light stabilizers are not particularly limited and include hindered amine-based light stabilizers. Antioxidants are not particularly limited and include hindered phenol-based antioxidants. Storage stabilizers include 4-methoxyphenol and dibutylhydroxytoluene. Adhesion enhancers are not particularly limited and include benzotriazole-based adhesion enhancers, silane coupling agents, titanium coupling agents, and zircon coupling agents. Organic or inorganic pigments are not particularly limited and include silica, alumina, carbon black, and aluminum paste. Organic beads, inorganic beads, and mixtures thereof are not particularly limited and include silica, alumina, acrylic resin beads, urethane resin beads, and organic beads containing organic or inorganic pigments.

[0071] The active energy ray-curable primer coating composition of the present invention may further contain a fluorescent whitening agent, which has the effect of reducing irradiation energy or shortening irradiation time by converting unused active energy rays into usable wavelengths. Examples of fluorescent whitening agents include 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, 7-diethylamino-4-methylcoumarin, and 7-(2H-naphtho[1,2-d]triazole-2-yl)-3-phenyl-2H-1-benzopyran-2-one. A commercially available example is Chinopearl OB CO (manufactured by BASF).

[0072] Method for forming a coating film: When manufacturing a reflective component for an automobile lamp using the active energy ray curable primer coating composition of the present invention, for example, the object to be coated is cleaned with a water-based cleaning agent, the primer coating composition of the present invention is applied to the surface of the molded product, solvent removal is performed, and then the primer layer is formed by irradiation with active energy rays. The above application can be carried out by general methods such as air spray painting, electrostatic painting, and dipping painting.

[0073] In the above coating process, the dry film thickness is set to 5 to 50 μm. Before UV-LED irradiation, preheating is performed at 60 to 130°C for 2 to 25 minutes to remove the solvent. If the solvent removal time is less than 2 minutes or the ambient temperature is below 60°C, solvent will remain in the coating film, reducing the appearance and moisture resistance of the coating. If the solvent removal time exceeds 25 minutes or the ambient temperature exceeds 130°C, sublimation of the photopolymerization initiator occurs, reducing UV-LED curability, water resistance, moisture resistance, and thermal cycling properties. The ambient temperature for solvent removal is preferably 65 to 120°C, more preferably 70 to 110°C, and the solvent removal time is preferably 2 to 10 minutes, more preferably 2 to 5 minutes.

[0074] The UV-LED used for active energy ray curing of the active energy ray curable primer coating composition of the present invention is composed of UV-LEDs having a peak wavelength of 200 to 405 nm, and has a structure in which one or more UV-LEDs with peak wavelengths are arranged on a substrate. Preferably, active energy rays from LEDs with a peak wavelength of 280 to 405 nm, more preferably from LEDs with a peak wavelength of 330 to 405 nm, are used for curing. LEDs with a peak wavelength of 405 nm or higher are in the visible light region and are used for illumination, etc., and are not suitable for curing active energy ray curable coatings, resulting in reduced curability, water resistance, and moisture resistance.

[0075] The integrated light intensity condition for the active energy rays used to cure the active energy ray-curable primer coating composition of the present invention is 0.1 J / cm². ２ Above, 2J / cm ２ The following is the result: The cumulative light intensity is 0.1 J / cm². ２If the value is less than 2 J / cm², the appearance, adhesion, water resistance, moisture resistance, heat resistance, thermal cycling properties, and the appearance and heat resistance of the vapor-deposited aluminum will deteriorate. UV-LEDs do not emit infrared rays and do not require consideration of thermal deformation of the coated object, so they can be exposed for longer periods than mercury lamps. Therefore, 2 J / cm² is appropriate. ２ Even if the exposure limit is exceeded, there is no effect on the curability or properties of the coating film due to the active energy rays. However, it becomes economically disadvantageous because it requires more lamps or longer irradiation times.

[0076] In this specification, the accumulated light intensity is the value measured using an EYE UV METER UVPF-A2 light meter manufactured by iGraphics Co., Ltd. For UV-LED lamps, a light receiving unit specifically for UV-LEDs (PD-3040A2) was attached, and for mercury lamps, a light receiving unit for UVA (PD-365A2) was attached for measurement.

[0077] When the active energy ray curable primer coating composition of the present invention is cured by irradiation with an LED lamp with a peak wavelength of 405 nm or higher, the coating appearance, adhesion, heat resistance, thermal cycling properties, and the appearance and heat resistance of the vapor-deposited aluminum are reduced because the formulation is not suitable.

[0078] When a mercury lamp, an iron-doped metal halide lamp, or a gallium-doped gallium lamp is used to cure the active energy ray-curable primer coating composition of the present invention, the coating appearance, thermal cycling properties, and appearance of the vapor-deposited aluminum deteriorate because the coating composition has a formulation suitable for UV-LED lamps.

[0079] The active energy ray-curable primer coating composition of the present invention is applied to concave automotive lamp reflective parts and irradiated with active energy rays to form a cured coating film, so its film thickness is 5 μm or more and 50 μm or less. If it is less than 5 μm, the appearance of the coating, heat resistance, thermal cycling properties, appearance of the vapor-deposited aluminum, and heat resistance will decrease. If it is 50 μm or more, UV-LED curability, water resistance, moisture resistance, heat resistance, thermal cycling properties, appearance of the vapor-deposited aluminum, and heat resistance will decrease, and the amount of paint used will increase, making it economically disadvantageous.

[0080] Various layers (e.g., metal layers) can be provided on the undercoat layer formed by the above method. Examples of metal vapor-deposited layers include aluminum vapor-deposited layers, indium vapor-deposited layers, and tin vapor-deposited layers. The metal vapor-deposited layer can be provided by known methods such as vacuum methods, sputtering methods (e.g., DC magnetron sputtering, RF sputtering, ion beam sputtering, etc.), electron beam vapor deposition, and ion plating. Furthermore, if the metal vapor-deposited layer is an aluminum vapor-deposited layer, it can also be formed by applying a paint composition containing vapor-deposited aluminum pigment.

[0081] A coating layer may be provided on the above-mentioned undercoat layer using, for example, a known paint composition containing a resin component such as acrylic resin or urethane resin. Alternatively, a coating layer may be provided on the above-mentioned metal vapor deposition layer as needed.

[0082] In this specification, parameters such as resins, UV monomers, and additives were determined in accordance with JIS K 0070 "Test Methods for Acid Value, Saponification Value, Ester Value, Iodine Value, Hydroxyl Value and Unsaponifiables of Chemical Products" for acid value, hydroxyl value, and iodine value. The acid value represents the number of mg of potassium hydroxide required to neutralize the free fatty acids, resin acids, etc. contained in 1 g of sample; the hydroxyl value represents the number of mg of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when 1 g of sample is acetylated; and the iodine value represents the amount of halogen bonded when 100 g of sample is reacted with a halogen, converted to the number of grams of iodine.

[0083] The weight-average molecular weight was measured by gel permeation chromatography using an HLC-8200 manufactured by Tosoh Corporation. The measurement conditions were as follows: Column: TSgel Super Multipore HZ-M (3 columns) Developing solvent: Tetrahydrofuran Column Inlet Oven: 40°C Flow rate: 0.35 ml Detector: RI Standard polystyrene Tosoh Corporation PS oligomer kit

[0084] The present invention will be further illustrated by the following examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[0085] Manufacturing example component (A): Synthesis of alkyd resin (The characteristic values ​​of components A-1 to A-12 are shown in Table 1.)

[0086] Manufacturing Example 1 Component A-1: ​​Tall Oil Fatty Acid Modified Alkyd Resin Solution 2565 g (8.88 mol) of tall oil fatty acid with an iodine value of 132 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 506 g (8.15 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 5070 g of xylene to obtain a tall oil fatty acid modified alkyd resin solution with a solid content of 55%.

[0087] Manufacturing Example 2 Component A-2: Soybean Oil Modified Alkyd Resin Solution 2603 g (2.96 mol) of soybean oil with an iodine value of 130 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4850 g of xylene to obtain a soybean oil modified alkyd resin solution with a solid content of 55%.

[0088] Manufacturing Example 3 Component A-3: Safflower Oil Modified Alkyd Resin Solution 2603 g (2.96 mol) of safflower oil with an iodine value of 148 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4850 g of xylene to obtain a safflower oil modified alkyd resin solution with a solid content of 55%.

[0089] Manufacturing Example 4 Component A-4: Castor Oil Modified Alkyd Resin Solution 2751 g (2.96 mol) of castor oil with an iodine value of 82 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4970 g of xylene to obtain a castor oil modified alkyd resin solution with a solid content of 55%.

[0090] Manufacturing Example 5 Component A-5: Palm oil modified alkyd resin solution 2553 g (2.96 mol) of palm oil with an iodine value of 53 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4820 g of xylene to obtain a palm oil modified alkyd resin solution with a solid content of 55%.

[0091] Manufacturing Example 6 Component A-6: Linseed Oil Modified Alkyd Resin Solution 2612 g (2.96 mol) of linseed oil with an iodine value of 190 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4870 g of xylene to obtain a linseed oil modified alkyd resin solution with a solid content of 55%.

[0092] Manufacturing Example 7 Component A-7: Tall Oil Fatty Acid Modified Alkyd Resin Solution 2565 g (8.88 mol) of tall oil fatty acid with an iodine value of 132 and 800 g (5.88 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 506 g (8.15 mol) of ethylene glycol were charged. While stirring, 2340 g (15.80 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4820 g of xylene to obtain a tall oil fatty acid modified alkyd resin solution with a solid content of 55%.

[0093] Production Example 8 Component A-8: Tall Oil Fatty Acid Modified Alkyd Resin Solution 2565 g (8.88 mol) of tall oil fatty acid with an iodine value of 132 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction medium. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 506 g (8.15 mol) of ethylene glycol were charged. While stirring, 2681 g (18.10 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 5150 g of xylene to obtain a tall oil fatty acid modified alkyd resin solution with a solid content of 55%.

[0094] Manufacturing Example 9 Component A-9: Tall Oil Fatty Acid Modified Alkyd Resin Solution 2565 g (8.88 mol) of tall oil fatty acid with an iodine value of 132 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction medium. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 250 g (1.84 mol) of pentaerythritol and 698 g (11.25 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4950 g of xylene to obtain a tall oil fatty acid modified alkyd resin solution with a solid content of 55%.

[0095] Manufacturing Example 10 Component A-10: Tall Oil Fatty Acid Modified Alkyd Resin Solution 2565 g (8.88 mol) of tall oil fatty acid with an iodine value of 132 and 1089 g (8.00 mol) of pentaerythritol were charged into a reaction medium. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 582 g (4.27 mol) of pentaerythritol and 506 g (8.15 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 5180 g of xylene to obtain a tall oil fatty acid modified alkyd resin solution with a solid content of 55%.

[0096] Manufacturing Example 11 Component A-11: Soybean Oil Modified Alkyd Resin Solution 2110 g (2.40 mol) of soybean oil with an iodine value of 130 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 520 g (3.82 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 4420 g of xylene to obtain a soybean oil modified alkyd resin solution with a solid content of 55%.

[0097] Manufacturing Example 12 Component A-12: Soybean Oil Modified Alkyd Resin Solution 3517 g (4.00 mol) of soybean oil with an iodine value of 130 and 963 g (7.07 mol) of pentaerythritol were charged into a reaction vessel. While stirring, the mixture was heated to 230°C over 2 hours and 30 minutes, removing the generated water from the system. After cooling to 150°C, 600 g (4.41 mol) of pentaerythritol and 206 g (3.32 mol) of ethylene glycol were charged. While stirring, 2535 g (17.12 mol) of phthalic anhydride and 148 g of xylene for circulation were added. The mixture was heated to 220°C over 3 hours, removing the generated water from the system, and the reaction was allowed to proceed until the desired acid value was reached. After the reaction was complete, the mixture was diluted with 5580 g of xylene to obtain a soybean oil modified alkyd resin solution with a solid content of 55%.

[0098]

[0099] Component (B): Mixture of dipentaerythulitol hexa and penta(meth)acrylate Examples Component B-1: Arronix M-400 (Hydroxyl value 38 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-2: NK ester A-DPH (Hydroxyl value 10 mg KOH / g) (Manufactured by Shin Nakamura Chemical Co., Ltd.) Component B-3: Arronix M-405 (Hydroxyl value 14 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-4: Arronix M-471 (Hydroxyl value 19 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-5: Arronix M-406 (Hydroxyl value 29 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-6: Arronix M-402 (Hydroxyl value 34 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-7: NK Ester A-9550 (Hydroxyl value 50 mg KOH / g) (Manufactured by Shin Nakamura Chemical Co., Ltd.) Comparative example Component B-8: Aronics M-403 (Hydroxyl value 53 mg KOH / g) (Manufactured by Toagosei Co., Ltd.) Component B-9: Neomer DA-600 (Hydroxyl value 72 mg KOH / g) (Manufactured by Sanyo Chemical Industries, Ltd.) The solid content of components B-1 to B-9 was 100%.

[0100] Component (C): Dia- or tria-functional (meth)acrylate having a cyclic structure within the molecule. Example Component C-1: M-208 (Bisphenol F ethylene oxide modified diacrylate manufactured by Toagosei Co., Ltd.) Component C-2: Ebecryl 130 (Tricyclodecanedimethanol diacrylate manufactured by Daicel Ornex Co., Ltd.) Component C-3: Aronics M-315 (Isocyanurate ethylene oxide modified triacrylate manufactured by Toagosei Co., Ltd.) Comparative Example: Dia- or tria-functional (meth)acrylate not having a cyclic structure within the molecule. Component C-4: Aronics M-220 (Tripropylene glycol diacrylate manufactured by Toagosei Co., Ltd.) The solid content of components C-1 to C-4 was 100%.

[0101] Component (D): Acrylic resin Example Production Example 13 Component D-1: Acrylic resin 2000 parts of butyl acetate were charged into a four-necked flask equipped with a heating device, stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping device, and the temperature was raised to 120°C while stirring and introducing nitrogen. Then, a mixed solution of 554.0 parts (5.53 mol) of methyl methacrylate, 249.4 parts (1.95 mol) of n-butyl acrylate, 185.6 parts (1.43 mol) of 2-hydroxyethyl methacrylate, 10.7 parts (0.12 mol) of methacrylic acid, and 2.3 parts of kaya ester-O, which is a polymerization initiator, was added dropwise from the dropping device over 3 hours. Then, stirring was continued for 120 minutes to complete the reaction. The obtained acrylic resin had a glass transition temperature of 40°C, an acid value of 7 mg KOH / g, a hydroxyl value of 100 mg KOH / g, a weight-average molecular weight of 8,100, and a solid content of 50%.

[0102] Production Example 13: Components D-2 to Production Example 34 D-22: An acrylic resin was obtained in the same manner as in Production Example 12, except that the components and amounts of the mixed solution used for acrylic resin polymerization were changed as shown in Tables 2 and 3. The glass transition temperature, hydroxyl value, acid value, and weight-average molecular weight of the obtained acrylic resin are shown together.

[0103]

[0104]

[0105] Component (E): Hydrogen abstraction type photopolymerization initiator Example Component E-1: Omnirad DETX (2,4-diethylthioxanthene-9-one manufactured by IGM Resins) Component E-2: 2-EAQ (2-ethylanthraquinone manufactured by Yamamoto Chemical Co., Ltd.) Component E-3: Omnipol TX (polyethylene glycol bis(9-oxo-9H-thioxanthenyloxy)acetate manufactured by IGM Resins) The solid content of components E-1 to E-3 was 100%.

[0106] Component (F): α-aminoalkylphenone-based photopolymerization initiator Example Component F-1: Omnirad 907 (2-methyl-4'-(methylthio)-2-morpholinopropiophenone manufactured by IGM Resins) Component F-2: Omnirad 379 (2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one manufactured by IGM Resins) Component F-3: Omnipol 910 (polyethylene glycol di(β-4-(2-dimethylamino-2-benzyl)butaonylphenyl)piperazine)propionate manufactured by IGM Resins) The solid content of components F-1 to F-3 was 100%.

[0107] Components (G): Amine Synergist Example Component G-1: Omnipol ASA (Polyethylene glycol bis(para-dimethylaminobenzoate) manufactured by IGM Resins) Component G-2: Omnirad EDB (Ethyl-4-(dimethylamino)benzoate manufactured by IGM Resins) Component G-3: Omnirad EHA (2-Ethylhexyl-4-(dimethylamino)benzoate manufactured by IGM Resins) The solid content of components G-1 to G-3 was 100%.

[0108] Ingredients (H): Organic solvent Component H: Xylene

[0109] The aforementioned component (I): Amino resin component I: Yuban 128 (Butylated melamine manufactured by Mitsui Chemicals, Inc.)

[0110] Other additives used included the silicon-based surface modifier BYK-306 (manufactured by Bic Chemie Co., Ltd.) and the cellulose-based surface modifier CAB551-0.2 (cellulose ester resin manufactured by Eastman Corporation).

[0111] The measurements were performed using UV-LED type ultraviolet irradiation devices equipped with peak wavelengths of 365, 375, 395, 405, and 420 nm, respectively. The integrated light intensity was measured using the EYE UV METER UVPF-A2 (photodetector PD-3040A2) manufactured by iGraphics Co., Ltd.

[0112] Ultraviolet irradiation was performed using EYE INOVERTOR GRANDAGE (4kW), a mercury lamp type ultraviolet irradiation device manufactured by I-Graphics Co., Ltd., equipped with high-pressure mercury lamps and metal halide lamps, respectively. The cumulative light intensity was measured using EYE UV METER UVPF-A2 (light receiving unit PD-365A2), also manufactured by I-Graphics Co., Ltd.

[0113] [Example 1] (1) Preparation of Active Energy Ray Curable Primer Composition 132 parts xylene was added to a stirring vessel. Subsequently, 36.4 parts of component A-1 (20 parts solids), 40 parts of component B-1, 15 parts of component C-1, 50 parts of component D-1 (25 parts solids), 5 parts each of component E-1, component F-1, and component G-1, and as surface modifiers, 0.1 part of BYK-306 manufactured by Bic Chemie and 0.5 parts of CAB-551-0.2 manufactured by Eastman were added and stirred until uniform to prepare an Active Energy Ray Curable Primer Composition with a solid content of 40%.

[0114] [Examples 2-69] Active energy ray curable coating compositions were prepared in the same manner as in Example 1, except that the types and amounts of each component were changed as shown in Tables 4-10. In Tables 4-10, the values ​​in parentheses for components (A) and (D) represent the solid content.

[0115] [Comparative Examples 1-49] Active energy ray curable coating compositions were prepared in the same manner as in Example 1, except that the types and amounts of each component were changed as shown in Tables 11-15. In Tables 11-15, the values ​​in parentheses for components (A) and (D) represent the solid content.

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[0128] (2) Preparation of evaluation boards treated with active energy ray curable coating compositions The active energy ray curable coating compositions of each example obtained in (1) were diluted with thinner (xylene) using a Ford cup #4 so that the viscosity at a liquid temperature of 20°C was 9 to 13 seconds. The resulting diluted coating was spray-coated onto a substrate (a 3 mm thick polycarbonate plate (Panlite L-1225: manufactured by Teijin)) so that the dried film thickness after curing was as shown in Tables 4 to 10. The formed uncured coating was desolvented by heating in a hot air drying oven at 80°C for 3 minutes. Next, the dried coating was irradiated with ultraviolet light of the integrated light amount shown in Tables 4 to 10 using a UV-LED lamp with a peak wavelength of 395 nm in air to form a cured coating and obtain an evaluation board.

[0129] In (2) above, a cured coating film was formed in the same manner as in Example 1, except that the active energy ray curable coating compositions of each comparative example obtained in (1) were used, and the solvent removal conditions, the dried film thickness after curing, the type of lamp, and the integrated light intensity were changed as shown in Tables 11 to 15, to obtain an evaluation plate.

[0130] (3) Preparation of an evaluation plate with aluminum vapor deposition treatment The material obtained in (2) was subjected to aluminum vapor deposition treatment by heating and evaporating aluminum under vacuum in a vacuum deposition apparatus to create an evaluation plate with a mirror-like vapor-deposited aluminum finish.

[0131] [Evaluation] The active energy ray-curable primer composition and its coated surface were evaluated according to the following evaluations, from Evaluation-1 to Evaluation-15. The evaluation results are shown in Tables 16 to 27.

[0132] The evaluation items and criteria for determining the evaluation results are shown below. Overall judgment ○: Pass (No issues in any evaluation item) ×: Fail (An issue exists in at least one evaluation item)

[0133] Evaluation - 1: Curability (Surface Tack) The coating film after irradiation was touched with a finger to check for tackiness (surface tack). ○: No surface tack △: Slight surface tack, but no fingerprints remain ×: Surface tack present, fingerprints remain ○ is a pass, △ and × are fail.

[0134] Evaluation-2: Paint Appearance (Surface Roughness) The arithmetic mean roughness Ra value of the paint evaluation board was measured in accordance with JIS B0601 using a surface roughness measuring instrument (Mitutoyo Corporation, SURFTESTS J-201P). Specifically, under the condition of a cutoff value of 2.5 mm (number of sections 5), the surface roughness was measured 7 times at different locations, and the average Ra value was calculated. The obtained Ra values ​​were evaluated according to the following criteria: ◎: Ra value is less than 0.2 μm 〇: Ra value is 0.2 μm or more and less than 0.4 μm △: Ra value is 0.4 μm or more and less than 0.8 μm ×: Ra value is 0.8 μm or more ◎ and 〇 are pass, △ and × are fail.

[0135] Evaluation - 3: Material Adhesion (Peeling of the coating from the material) In accordance with JIS K 5600 "General Test Methods for Paints" Cross-cut test, 25 squares were created on a paint evaluation board at 2 mm intervals using a cutter guide. Cellophane tape was applied and peeled off at a 60° angle, and the number of squares that peeled off from the material was checked and evaluated. ○: No peeling △: 1 to 5 squares peeled ×: 6 or more squares peeled ○ is a pass, △ and × are a fail.

[0136] Evaluation - 4: Intralayer fracture adhesion (fracture and peeling of the coating film within a layer) In accordance with JIS K 5600 "General Test Methods for Paints" cross-cut test, 25 squares were created on a paint evaluation board at 2 mm intervals using a cutter guide, cellophane tape was applied, and the tape was peeled off at a 60° angle to check and evaluate the number of squares in which fracture and peeling occurred within the layers of the coating film. ○: No peeling within the layer △: Peeling within the layer occurred in 1 to 5 squares ×: Peeling within the layer occurred in 6 or more squares ○ is a pass, and △ and × are a fail.

[0137] Evaluation - 5: Water Resistance Test (Appearance) The painted evaluation board was immersed in 40°C hot water for 240 hours. After that, it was removed from the water and dried at room temperature for 1 hour. The appearance of the paint film was visually observed and evaluated for abnormalities (wrinkles, cracks, blistering, loss of gloss, and discoloration) according to the following criteria. Levels where minor abnormalities were observed were re-evaluated after 24 hours. ◎: No abnormalities ○: Minor abnormalities, no abnormalities after 24 hours △: Minor abnormalities, abnormalities after 24 hours (no recovery) ×: Abnormalities ◎ and ○ are pass, △ and × are fail.

[0138] Evaluation - 6: Water Resistance Test (Adhesion) The painted evaluation board was immersed in 40°C hot water for 240 hours. After that, it was removed from the water and dried at room temperature for 1 hour. The adhesion test was performed in the same manner as in (3) Adhesion. ○: No peeling △: 1 to 5 squares peeled ×: 6 or more squares peeled ○ is a pass, △ and × are a fail.

[0139] Evaluation - 7: Humidity Resistance Test (Appearance) The painted evaluation board was left in a humidity resistance test chamber at a temperature of 55°C and a humidity of 95% or higher for 240 hours. After that, it was removed from the test chamber and dried at room temperature for 1 hour. The appearance of the paint film was visually observed and evaluated for abnormalities (wrinkles, cracks, blistering, loss of gloss, and discoloration) according to the following criteria. Levels where minor abnormalities were observed were re-evaluated after 24 hours. ◎: No abnormalities ○: Minor abnormalities present, no abnormalities after 24 hours △: Minor abnormalities present, abnormalities present after 24 hours (no recovery) ×: Abnormalities present ◎ and ○ are pass, △ and × are fail.

[0140] Evaluation-8: Heat Resistance Test (Appearance) The painted evaluation board was left in a heat resistance tester at 80°C for 240 hours. After that, it was removed from the tester and cooled to room temperature for 1 hour. The appearance of the coating was visually observed and evaluated for abnormalities (wrinkles, cracks, loss of gloss, and discoloration) according to the following criteria. ○: No abnormalities △: Minor abnormalities present ×: Abnormalities present ○ means passing, △ and × mean failing.

[0141] Evaluation-9: Thermal Cycling Test (Appearance) The painted evaluation board was subjected to a thermal cycling test machine, repeating the cycle 10 times between 80°C for 4 hours and -30°C for 4 hours. After removing it from the machine, the appearance of the coating was visually inspected after 1 hour, and any abnormalities (wrinkles, cracks, loss of gloss, and discoloration) were evaluated according to the following criteria. ○: No abnormalities △: Minor abnormalities present ×: Abnormalities present ○ indicates a pass, while △ and × indicate a fail.

[0142] Evaluation - 10: Storage stability of paint (separation, turbidity, discoloration, etc.) The paint composition was sealed in a paint can and left in a constant temperature chamber at 40°C for 240 hours. After being removed from the constant temperature chamber, it was left for 24 hours to reach room temperature, and the can lid was opened to check the condition of the paint composition. The paint composition was visually inspected to check for abnormalities such as separation, turbidity, and discoloration. ○: No abnormalities such as separation, turbidity, or discoloration △: Slight separation, slight discoloration, or slight turbidity ×: Separation, discoloration, or turbidity ○ indicates a pass, while △ and × indicate a fail.

[0143] Evaluation - 11: Storage Stability of Paint (Gelation) The paint composition was sealed in a paint can and left in a constant temperature chamber at 40°C for 240 hours. After being removed from the constant temperature chamber, it was left to stand for 24 hours until it reached room temperature. The can lid was opened, and the paint composition was stirred until uniform. It was then poured onto a glass plate. ○: No gelling or other substances derived from the paint composition were found on the glass plate. △: A small amount of gelling or other substances derived from the paint composition were found on the glass plate. ×: A large amount of gelling or other substances derived from the paint composition were found on the glass plate. It could not be poured onto glass. It had solidified. ○ indicates a pass, while △ and × indicate a fail.

[0144] Evaluation - 12: Productivity, Economy, and Safety (Cost, Time, Environment) The feasibility of achieving productivity, economy, and safety in the production of an active energy ray curable primer coating composition for automotive lighting reflective components and automotive lighting reflective components with a metal mirror surface coated with the said coating composition was evaluated. ○: No issues with productivity, economy, or safety. △: Issues with one or more of productivity, economy, or safety. ×: Issues with all of productivity, economy, and safety. ○ means passing, while △ and × mean failing.

[0145] Evaluation - 13: Appearance of the evaluation plate after aluminum vapor deposition treatment The evaluation plate that underwent aluminum vapor deposition treatment was visually inspected and evaluated according to the following criteria. ○: A mirror surface is formed. △: Slight clouding or iridescence occurs on the mirror surface, but the mirror condition is maintained. ×: Clouding, iridescence, etc. occur on the mirror surface, and it is not a mirror condition. ○ is a pass, and △ and × are fail.

[0146] Evaluation - 14: Adhesion of evaluation boards treated with aluminum vapor deposition An evaluation board treated with aluminum vapor deposition was cross-cut with a utility knife, and an adhesion test was performed using cellophane tape. ○: No peeling of the aluminum vapor deposition layer. △: The aluminum vapor deposition layer peeled slightly at the cross-cut area. ×: The aluminum vapor deposition layer peeled off where the cellophane tape was applied. ○ indicates a pass, while △ and × indicate a fail.

[0147] Evaluation - 15: Appearance of Aluminum-Deposited Coatings After Heat Resistance Test An evaluation plate treated with aluminum vapor deposition was placed in a heat resistance test machine at 120°C for 36 hours. After removing it from the machine, the appearance of the coating was visually inspected one hour later, and the mirror surface of the aluminum vapor deposition was evaluated for bubbles, wrinkles, and cracks according to the following criteria. ○: No bubbles, wrinkles, or cracks, and the mirror surface is maintained. △: Slight bubbles, wrinkles, or cracks occur, but the mirror surface is maintained. ×: Bubbles, wrinkles, or cracks occur, and the mirror surface is not maintained. ○ is a pass, and △ and × are a fail.

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[0160] As shown in Tables 16-27, the active energy ray curable primer paint composition obtained in the examples showed sufficient curability and performance even when using a UV-LED light source, and a method for curing the composition was obtained.

[0161] The present invention provides an active energy ray curable primer coating composition that hardens with active energy rays emitted from a UV-LED lamp, and a method for manufacturing a coated article. The composition contains the following essential components: (A) an alkyd resin component, (B) a mixture of dipentaerythritol hexa and penta(meth)acrylate, (C) a 2-3 functional (meth)acrylate component having a cyclic structure in the molecule, (D) an acrylic resin component, (E) a hydrogen abstraction type photopolymerization initiator component, (F) an α-aminoalkylphenone-based photopolymerization initiator component, (G) an amine synergist component, and (H) an organic solvent. By including these as essential components, the composition hardens with a UV-LED light source and can obtain the necessary and sufficient properties for use as an automotive lighting reflective material, contributing to energy saving and environmental protection.

Claims

Component (A): Alkyd resin Component (B): Mixture of dipentaerythritol hexa and penta(meth)acrylate Component (C): Dialytic or trifunctional (meth)acrylate having a cyclic structure within the molecule. Ingredient (D): Acrylic resin Component (E): Hydrogen abstraction type photopolymerization initiator Ingredient (F): α-aminoalkylphenone-based photopolymerization initiator Ingredient (G): Amine Synergist Ingredients (H): Organic solvent It contains as an essential component, The aforementioned component (A) has an oil length of 35-45%, an acid value of 0.01-10 mgKOH / g, a hydroxyl value of 120-150 mgKOH / g, and a weight-average molecular weight of 80,000-150,000. The aforementioned component (B) has a hydroxyl value of 50 mg KOH / g or less. The aforementioned component (D) has a glass transition temperature of 10 to 70°C, an acid value of 2 to 10 mg KOH / g, a hydroxyl value of 40 to 120 mg KOH / g, and a weight-average molecular weight of 4,000 to 20,000. With respect to 100 parts by mass of the total solid content of component (A), component (B), component (C), and component (D), The solid content of component (A) is 15 parts by mass or more and 25 parts by mass or less. The solid content of component (B) is 30 parts by mass or more and 50 parts by mass or less. The solid content of component (C) is 10 parts by mass or more and 20 parts by mass or less. The solid content of component (D) is 20 parts by mass or more and 30 parts by mass or less. The content of component (E) is 1 part by mass or more and 10 parts by mass or less. The content of the aforementioned component (F) is 1 part by mass or more and 10 parts by mass or less. An active energy ray curable primer paint composition for automotive lighting reflective members to which a metallic mirror surface is applied, characterized in that the content of component (G) is 3 parts by mass or more and 15 parts by mass or less. 　 The paint composition according to claim 1 further comprises component (I): an amino resin, wherein the content of component (I) is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total solid content of components (A), (B), (C), and (D), as described in claim 1. 　 The active energy ray curable primer paint composition for automotive lamp reflective members to which a metallic mirror surface is applied, according to claim 1 or 2, wherein the component (A) is modified with at least one selected from the group consisting of tall oil fatty acids, soybean oil, safflower oil, castor oil, and mixtures thereof, and has an iodine value of 80 to 160 when alone or when two or more fatty acids and oils are mixed. 　 The active energy ray curable primer paint composition for automotive lamp reflective members to which a metallic mirror surface is applied, according to claim 1 or 2, wherein the component (C) has a bisphenol A structure, a bisphenol F structure, a bisphenol AF structure, a 1,3-dioxane structure, a tricyclodecane structure, or a triazine ring. 　 A method for manufacturing a painted article, characterized in that an active energy ray-curable primer paint composition for automotive lamp reflective members that provides a metallic mirror surface as described in claim 1 or 2 is applied to a workpiece which is an automotive lamp reflective member, active energy rays are irradiated after solvent removal to form a cured coating film, the film thickness of which is 5 μm or more and 50 μm or less, and in subsequent steps, a metallic mirror surface is obtained on the surface of the workpiece by metal deposition, metal sputtering, silver mirror reaction and mirror surface forming coating.

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