JP5467302B1 - UV curable resin composition and design coating film - Google Patents

Abstract

An object of the present invention is to provide an ultraviolet curable resin composition and a design coating film capable of applying a beautiful design having a three-dimensional appearance without requiring a special operation regardless of the heat resistance of an object to be coated. Is to provide. The ultraviolet curable resin composition according to the present invention includes at least one selected from an acrylate monomer, an acrylate oligomer, and an acrylic acid oligomer, a benzophenone photopolymerization initiator as a photopolymerization initiator, and an aminobenzoate photopolymerization start. And at least one selected from α-hydroxyalkylphenone photopolymerization initiators. Moreover, the designable coating film according to the present invention is a designable coating film comprising a coating layer obtained by applying and curing the ultraviolet curable resin composition according to the present invention on the surface of the coating object, Has a mesh pattern.

Description

  The present invention relates to an ultraviolet curable resin composition and a designable coating film capable of giving a beautiful design.

  In recent years, home appliances such as mobile phones have been required to have high design properties. For example, three-dimensional and characteristic designs are applied by painting.

  There has been proposed a coating composition that uses a sulfonic acid neutralized with a large excess of a secondary amine as a curing catalyst, and forms a paint film having a wrinkle pattern using the curing catalytic action (for example, Patent Document 1). reference.). A hammer tone paint in which fine particles of a vinyl polymer antifoaming agent act on the surface of a coating film to form a hammer tone pattern has been proposed (see, for example, Patent Document 2). Also, without adding a surfactant, a paint to which a volatile flake such as aluminum powder or a pearl pigment is added is spray-coated as fine droplets, and then the same or the same quality paint as this paint is applied to this liquid. It has been proposed that a coating giving a three-dimensional effect can be formed by spray coating as droplets larger than droplets (see, for example, Patent Document 3).

JP-A-5-39443 JP-A-6-287482 JP-A-11-293156

  The paint composition described in Patent Document 1 is exemplified by plastics in addition to metals, wood, cement, and the like as the object to be coated, but the maximum material temperature during curing is 120 to 260 ° C. for 5 seconds. It is necessary to carry out treatment for ˜30 minutes, and in reality, it is limited to those having heat resistance. The paint described in Patent Document 2 has a problem that the solid content concentration must be within a predetermined range in order to form a pattern, and adjustment is troublesome. Moreover, the coating method described in Patent Document 3 requires special techniques such as adjustment of spray pressure. So far, a composition or a coating method has been proposed that can form a pattern having a highly designed and three-dimensional appearance without requiring special operations such as adjustment of solid content concentration and adjustment of spray pressure. Absent.

  An object of the present invention is to provide an ultraviolet curable resin composition and a design coating film capable of applying a beautiful design having a three-dimensional appearance without requiring a special operation regardless of the heat resistance of an object to be coated. Is to provide.

The present inventors can form a coating film having a network pattern by a general operation in ultraviolet curing by using a specific monomer or oligomer and a specific photopolymerization initiator in combination with the resin composition. As a result, the present invention has been completed. That is, the ultraviolet curable resin composition according to the present invention includes: (1) ethylene oxide modified bisphenol A diacrylate, (2) neopentyl glycol diacrylate, (3) dipentaerythritol hexaacrylate, ethylene oxide modified bisphenol F diacrylate. , any one of pentaerythritol triacrylate and trimethylolpropane triacrylate, the (1) (2) and three combinations of acrylate monomers chromatography (3), and a benzophenone-based photopolymerization initiator as a photopolymerization initiator And a coating layer having a mesh pattern formed by randomly extending concave, convex, or crack-like linear portions by photocuring .

The ultraviolet curable resin composition according to the present invention, the content of the photopolymerization initiator is preferably 0.5 to 40 parts by weight with respect to the acrylate monomer-1 00 parts by weight. A coating film having high adhesion and good curability and pattern formation can be formed.

The designable coating film according to the present invention is a designable coating film provided with a coating layer obtained by applying and curing the ultraviolet curable resin composition according to the present invention on the surface of an object to be coated, wherein the coating layer has a concave shape. Further, the present invention is characterized by having a mesh pattern formed by randomly extending convex or crack-like linear portions .

  In the designable coating film according to the present invention, the coating layer is divided into a 5 mm × 5 mm square lattice, and at least one of the divided 5 mm × 5 mm square regions has 2 to 200 small sections depending on the mesh pattern. It is preferable to be divided into two. It can be a more beautiful design.

  In the designable coating film according to the present invention, it is preferable that the coating layer is an undercoat layer, and a topcoat layer is further provided on the surface of the undercoat layer. Various designs can be given. The surface smoothness of the coating film can be increased. Moreover, durability can be improved.

  In the designable coating film according to the present invention, it is preferable that a metal layer is further provided between the undercoat layer and the topcoat layer. Furthermore, it can be set as a beautiful metallic design.

  The present invention provides an ultraviolet curable resin composition and a design coating film capable of applying a beautiful design having a three-dimensional appearance without requiring a special operation regardless of the heat resistance of an object to be coated. can do.

It is a picked-up image by the microscope which shows the 1st example of an application layer. It is a picked-up image by the microscope which shows the 2nd example of an application layer. The state which divided | segmented the coating layer of FIG. 1 into the grid | lattice form of 5 mm x 5 mm square is shown. It is an image which shows an example of the designable coating film which concerns on this embodiment. 2 is a SEM image showing a surface state and a cross-sectional state of a coating layer of the designable coating film of Example 1. FIG. 2 is an SEM image showing a surface state and a cross-sectional state of a top coat layer of the designable coating film of Example 1. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. Various modifications may be made as long as the effects of the present invention are achieved.

The ultraviolet curable resin composition according to this embodiment includes (1) ethylene oxide modified bisphenol A diacrylate, (2) neopentyl glycol diacrylate, (3) dipentaerythritol hexaacrylate, ethylene oxide modified bisphenol F diacrylate, any one of pentaerythritol triacrylate and trimethylolpropane triacrylate, the (1) (2) and three combinations of acrylate monomers chromatography (3), a benzophenone photopolymerization initiator as a photopolymerization initiator A coating layer having a mesh pattern formed by randomly extending concave, convex, or crack-like linear portions is formed by photocuring .

  An acrylate monomer is an ester of (meth) acrylic acid, and is a component that forms a network pattern by polymerization and curing upon irradiation with ultraviolet rays. Here, (meth) acrylic acid includes acrylic acid and methacrylic acid.

  The acrylate monomer is preferably an ester of (meth) acrylic acid and a polyol. A polyol is a compound having two or more hydroxyl groups in the molecule, and includes polyhydric alcohols and polyhydric phenols.

  The polyhydric alcohol is, for example, pentaerythritol, dipentaerythritol, trimethylolpropane, dipropylene glycol, 1,6-hexanediol, tripropylene glycol, polyethylene glycol, neopentyl glycol, tricyclodecane dimethanol, glycerin or ditrimethylol. Propane or a modified product thereof.

  The polyhydric phenol is, for example, bisphenol A, bisphenol F, or a modified product thereof. Here, the modified product is, for example, an ethylene oxide (EO) modified product or a propylene oxycide (PO) modified product.

  Esters of acrylic acid and polyol are, for example, bisphenol A di (meth) acrylate, modified bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate, modified bisphenol F di (meth) acrylate, pentaerythritol tri (meth) ) Acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate , Polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethano Rudi (meth) acrylate, neopentyl glycol hydroxypivalate ester di (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, glycerin propoxytri (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, ditrimethylolpropane tetra (Meth) acrylate and pentaerythritol tetra (meth) acrylate. These may be used alone or in combination of two or more.

  Esters of acrylic acid and polyol can be cured moderately and efficiently form a network pattern, so that modified bisphenol A diacrylate, modified bisphenol F diacrylate, pentaerythritol triacrylate (PETIA), diester It is preferably at least one of pentaerythritol hexaacrylate (DPHA) and trimethylolpropane triacrylate (TMPTA). Here, the modified bisphenol A diacrylate or the modified bisphenol F diacrylate is more preferably an EO-modified product.

  The acrylate oligomer is, for example, a urethane acrylate oligomer or a polyester acrylate oligomer. Among these, a polyester acrylate oligomer is more preferable. An acrylate oligomer may be used individually by 1 type, or may use 2 or more types together.

  Examples of the acrylic acid oligomer include acrylic acid dimer, ε-caprolactone-modified tris (acryloxyethyl) isocyanurate, and trisacryloyloxyethyl isocyanurate.

  A benzophenone photopolymerization initiator is a component that initiates a polymerization reaction of an acrylate monomer, an acrylate oligomer, or an acrylic acid oligomer by irradiation with ultraviolet rays. The benzophenone photopolymerization initiator is a compound having a benzophenone skeleton, and examples thereof include benzophenone, 4-methylbenzophenone, 4,4'-bis (dimethylamino) benzophenone, and 4,4'-bis (diethylamino) benzophenone.

  The aminobenzoate photopolymerization initiator is, for example, 2-ethylhexyl-4-dimethylaminobenzoate or ethyl-4-dimethylaminobenzoate.

  The α-hydroxyalkylphenone photopolymerization initiator is, for example, 1-hydroxy-cyclohexyl-phenyl-ketone.

  In the ultraviolet curable resin composition according to this embodiment, the content of the photopolymerization initiator is 0.5 to 40 parts by mass with respect to 100 parts by mass of the acrylate monomer, the acrylate oligomer, and the acrylic acid oligomer. Is preferred. More preferably, it is 0.5-30 mass parts, More preferably, it is 1-15 mass parts, Most preferably, it is 2-6 mass parts. If it is less than 0.5 mass part, it may be inferior to sclerosis | hardenability and adhesiveness with a to-be-coated object may not be obtained. Even if it exceeds 40 mass parts, the effect according to a compounding quantity is not acquired but it is uneconomical. Here, when two or more kinds of acrylate monomers, acrylate oligomers and acrylic acid oligomers are used in combination, the content of the photopolymerization initiator is the total mass of the acrylate monomers, acrylate oligomers and acrylic acid oligomers. The content is relative to 100 parts by mass.

  The ultraviolet curable resin composition preferably further contains an acrylic resin. The acrylic resin mainly has a role as an anti-repellent agent. The acrylic resin itself is a non-polymerizable resin having no polymerization reactivity, and is a polymer or copolymer of an acrylate ester or a methacrylate ester. In this embodiment, there is no restriction | limiting in particular in the kind of acrylic ester or methacrylic ester used as the raw material of acrylic resin.

  The ultraviolet curable resin composition may further contain various additives such as a leveling agent, a pigment, a dye, and a stabilizer. The leveling agent is, for example, a fluorine-based leveling agent or a silicon-based leveling agent. When a topcoat layer is formed on a coating film formed by coating an ultraviolet curable resin composition, a fluorine-based leveling agent is preferable because it does not affect the adhesion of the topcoat layer.

  The ultraviolet curable resin composition may further contain a light stabilizer. The light stabilizer has a role of relaxing the progress inside the coating film and making the pattern appear more stably when the peak intensity at the time of curing is too high. The light stabilizer is, for example, an ultraviolet absorber (UVA) such as a hindered amine light stabilizer (HALS), a benzotriazole (BTZ) ultraviolet absorber, or a triazine (HPT) ultraviolet absorber. More preferably, HALS and UVA are used in combination. The light stabilizer is preferably 3% by mass or less, more preferably 1% by mass or less, relative to the coating film component. When it exceeds 3 mass%, adhesiveness with a base material may fall.

  The ultraviolet curable resin composition preferably further contains a solvent. The solvent mainly has a role as a medium for proceeding the polymerization reaction, a role for uniformly dissolving or dispersing the coating film component, a role as a diluent for adjusting the viscosity suitable for the coating work, and a role for adjusting curability. Have. Examples of the solvent include acetone (AT) (boiling point 56.3 ° C.), ethyl acetate (EAC) (boiling point 77.1 ° C.), methyl ethyl ketone (MEK) (boiling point 79.5 ° C.) and the like having a boiling point of 100 ° C. or less. (Hereinafter referred to as low boiling point solvent), methyl isobutyl ketone (MIBK) (boiling point 116.7 ° C.), butyl acetate (BAC) (boiling point 126.3 ° C.), isobutyl alcohol (I-BOH) (boiling point 108 ° C.), Solvents with boiling points exceeding 100 ° C. and below 150 ° C. such as toluene (TO) (boiling point 110.6 ° C.) (hereinafter referred to as medium boiling solvents), diisobutyl ketone (DIBK) (boiling point 168.2 ° C.), isobutyl isobutyrate (IBIB) (151 ° C.), butyl cellosolve (buticero) (boiling point 171.2 ° C.), isophorone (boiling point 215.2 ° C.), etc. Later, is that the high-boiling point solvent.). A solvent may be used independently or may use 2 or more types together. Among these, it is more preferable to use a low-boiling solvent mixed with a medium-boiling solvent or a high-boiling solvent from the viewpoint that the photocurability of the acrylate monomer, acrylate oligomer or acrylic acid oligomer can be improved.

  The boiling point (1 atm) of the solvent is preferably 50 to 200 ° C. More preferably, it is 50-130 degreeC. If it is less than 50 degreeC, it may be inferior to coating workability | operativity. When it exceeds 200 ° C., curability may be inferior.

  In the ultraviolet curable resin composition which concerns on this embodiment, it is preferable that content of an acrylate-type monomer, an acrylate-type oligomer, and an acrylic acid-type oligomer is 40-100 mass parts with respect to 100 mass parts of coating film components. More preferably, it is 70-100 mass parts. When the content of the acrylate monomer, acrylate oligomer and acrylic acid oligomer is less than 40 parts by mass with respect to 100 parts by mass of the coating film component, the curability is inferior and an effective network pattern may not be formed. Here, the coating film component refers to a component remaining as a coating layer, in other words, a component excluding a component that volatilizes during the formation of the coating layer in the ultraviolet curable resin composition. The component that volatilizes when the coating layer is formed is, for example, a solvent.

  FIG. 1 is a photographed image by a microscope showing a first example of a coating layer. FIG. 2 is a photographed image by a microscope showing a second example of the coating layer. The designable coating film according to the present embodiment is a designable coating film including a coating layer obtained by applying and curing the ultraviolet curable resin composition according to the present embodiment on the surface of an object to be coated, and FIG. As shown in 2, the coating layer has a mesh pattern.

  The material of the object to be coated is not particularly limited. For example, acrylonitrile butadiene styrene copolymer (ABS), polypropylene (PP), polyamide (PA), polycarbonate (PC), polyphenylene ether (PPE), polyethylene terephthalate (PET). , Polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), and polyacetal (POM). The shape of the object to be coated is not particularly limited. For example, parts of home appliances such as a casing, buttons, panels, keyboards, etc., mobile phones or personal computers, handles, door knobs, buttons, dashboards, engine covers, wheel caps, etc. Car interior and exterior parts. The design coating film is formed on the outer surface, the inner surface, or the entire surface. In addition, you may surface-treat for the purpose of improving the adhesiveness with the designable coating film on the surface of a to-be-coated article.

  The surface of the object to be coated preferably has a property of not reflecting ultraviolet rays. When the surface of the coated material reflects ultraviolet rays, double curing in which the curing reaction proceeds not only with incident light but also with reflected light occurs, and the pattern may not be formed stably. Examples of the form in which the surface of the object to be coated has a property of not reflecting ultraviolet rays include a form in which the object to be coated transmits ultraviolet light or a form in which the object to be coated absorbs ultraviolet light.

  A coating layer consists of a photocured material of the ultraviolet curable resin composition which concerns on this embodiment, and has a mesh pattern as shown in FIG. 1 or FIG. The mesh pattern is a pattern formed by randomly extending concave, convex, or crack-like linear portions, and the portions where the linear portions intersect with other linear portions to form a mesh and other lines Including the part where the extension stops without crossing the shape part.

  FIG. 3 shows a state in which the coating layer of FIG. 1 is divided into a 5 mm × 5 mm square grid. In the designable coating film according to the present embodiment, as shown in FIG. 3, the coating layer is divided into a 5 mm × 5 mm square lattice, and a divided 5 mm × 5 mm square region (hereinafter referred to as a unit region). At least one is preferably divided into 2 to 200 small sections by a mesh pattern. More preferably, it is divided into 3 to 150 small sections. If it is less than 2, it is difficult to say that a beautiful mesh pattern is formed. When the number exceeds 200, it is difficult to visually recognize the mesh pattern, and it is difficult to say that the design is high. “A unit area is divided into small sections by a mesh pattern” means that a linear part intersects with another linear part in the unit area and is divided into small sections, and the linear part crosses the unit area. It is divided into small sections. More specifically, referring to FIG. 3, the unit area denoted by A1 is divided into two small sections by a mesh pattern. The unit area marked with A2 is divided into four small sections by a mesh pattern. Moreover, the unit area | region which attached | subjected B1 does not have a mesh pattern, and is not divided | segmented into a subdivision. The unit region marked with B2 has a linear portion, but is not divided into small sections. The ratio of the number of unit regions divided into small sections by a mesh pattern to the total number of unit regions on the coating layer (hereinafter referred to as pattern formation rate) is preferably 50% or more, more preferably 100%, That is, all unit areas are divided into small sections by a mesh pattern. In the coating film of FIG. 3, the number of unit areas on the coating layer is 108 and the number of unit areas divided into small sections by the mesh pattern is 78, so the pattern formation rate is 72%. The observation of the mesh pattern is preferably performed on the entire surface of the product, but if the entire product is difficult to observe, such as a large product, or if there is a specific area where the mesh pattern should be evaluated, the You may carry out about a part of surface. Further, the observation may be performed with a microscope, for example, with magnification of 10 times or 100 times, or may be visually observed.

Hatched when selecting an area of 1 cm ² to include network 1 or more in the coating layer, it is preferable that the average area within the region of the mesh is 0.005~0.5cm ^2. More preferably 0.0125~0.2cm ^2. If it is less than 0.005 cm ^2, it is difficult to visually recognize the mesh, and it is difficult to say that the design is high. If it exceeds 0.5 cm ² , it is difficult to say that a beautiful mesh pattern is formed. Here, the region of 1 cm ² is not limited to a 1 cm × 1 cm square, and the shape of the region is not limited as long as it has an area of 1 cm ² .

The mesh size of the mesh pattern can be adjusted by, for example, the type of monomer or oligomer to be selected and the boiling point of the solvent. The relationship between the size of the mesh and the type of monomer or oligomer is, for example, that EO-modified bisphenol A diacrylate and EO-modified bisphenol F diacrylate form a relatively small mesh pattern, and PETIA and DPHA are relatively large. A mesh pattern is formed. Then, TMPTA forms a mesh pattern having a size that is intermediate between a small mesh and a large mesh. Moreover, you may adjust the magnitude | size of the mesh of a mesh pattern by using together 2 or more types of monomers or oligomers. As an example, when EO-modified bisphenol A diacrylate and DPHA are used in combination, and the blending ratio of DPHA with respect to EO-modified bisphenol A diacrylate is increased, the mesh pattern is higher than when EO-modified bisphenol A diacrylate is used alone. The mesh can be enlarged. The relationship between the size of the mesh and the boiling point of the solvent has a relationship that the size of the mesh increases as the boiling point of the solvent increases. In particular, when the boiling point of the solvent is 170 ° C. or higher, a large mesh is formed. Here, the large mesh is, for example, a state in which the unit region is divided into 2 to 20 small sections by a mesh pattern, and an average area of the mesh in the 1 cm ² region is 0.05 to ⁵ cm ² . Small mesh, for example, a state in which the unit area is divided into 41 to 200 pieces of small section by a mesh pattern, the average area of the mesh of 1 cm ² area in the state of 0.005~0.025cm ^2. An intermediate mesh size is, for example, a state in which the unit area is divided into 21 to 39 small sections by a mesh pattern, and the average area of the mesh in the 1 cm ² area exceeds 0.025 cm ² and 0.05 cm The state is less than ² .

  The glossiness of the pattern varies depending on the boiling point of the solvent of the resin composition, the UV irradiation amount, and the type of monomer or oligomer to be blended. For example, when the solvent is a high-boiling solvent, when the UV irradiation amount is low and slightly uncured, or when the number of photoreactive functional groups is small and the amount of the low-reactivity monomer or oligomer is large, it is shown in FIG. As described above, the inside of the mesh is flat and glossiness is high, and the solvent is a low-boiling solvent or medium-boiling solvent, when the UV irradiation amount is high, or the number of photoreactive functional groups is large and the monomer or oligomer having high reactivity. When the blending amount is large, a striped pattern is formed inside the mesh as shown in FIG. 2, resulting in a matte wind with low gloss.

  The thickness of the coating layer is preferably 5 to 100 μm. More preferably, it is 15-60 micrometers. If it is less than 5 μm, the mesh pattern may not be formed effectively. If it exceeds 100 μm, it takes time to cure and the productivity is poor. Moreover, it may become uncured.

  FIG. 4 is an image showing an example of a designable coating film according to the present embodiment. In the design coating film according to the present embodiment, it is preferable that the coating layer is an undercoat layer and a topcoat layer is further provided on the surface of the undercoat layer. The top coat layer mainly has a role of imparting various design properties such as color and texture, a role of improving surface smoothness, and a role of protecting the coating layer. The topcoat layer contains, for example, a curable resin such as an acrylic resin, a urethane resin, an acrylic urethane resin, an acrylic silicon resin, an epoxy resin, a polyester resin, or a fluorine resin. The topcoat layer may contain a colorant such as a colored pigment or a dye, and a bright material such as a pearl pigment or a metallic pigment. The topcoat layer may further contain various additives such as a leveling agent and a stabilizer. Examples of the topcoat layer include clear (colorless and transparent), color clear (colored and transparent), and solid color (single color).

  The thickness of the top coat layer is preferably 5 to 50 μm. More preferably, it is 10-30 micrometers.

  In the designable coating film according to the present embodiment, it is preferable to further include a metal layer between the undercoat layer (coating layer) and the topcoat layer. The metal of the metal layer is, for example, aluminum, tin, indium, gold, silver, copper, or chromium.

  When the metal layer is provided, the topcoat layer is preferably clear or color clear. By providing an undercoat layer (coating layer), a metal layer, and a clear topcoat layer in this order on the surface of the object to be coated, a three-dimensional combination of the undercoat layer (coating layer) mesh pattern and the metallic feel of the metal layer. And, it becomes a coating film with a beautiful metallic design. In addition, by providing an undercoat layer (coating layer), a metal layer, and a color clear topcoat layer in this order on the surface of the object to be coated, the mesh pattern of the coating layer, the metallic feeling of the metal layer, and the color feeling of the topcoat layer By combining the two, a very beautiful coating film that is three-dimensional and metallic and has various color variations.

  The thickness of the metal layer is preferably 3 to 100 nm. More preferably, it is 10-70 nm.

  Up to this point, the design coating film has been described in the form of two or more layers in which the coating layer is an undercoat layer and the top coat layer is further provided on the surface of the undercoat layer. The film may have a single layer structure in which the coating layer is a top coat layer.

  Next, a method for forming a coating film according to this embodiment will be described. The formation method of the designable coating film which concerns on this embodiment has an application layer formation process. The coating layer forming step includes a first coating step of coating the ultraviolet curable resin composition on the surface of the object to be coated, and a first curing step of irradiating the coating surface with ultraviolet rays to cure.

  In the first application step, the method for applying the ultraviolet curable resin composition is not particularly limited, and is a known method such as a brush coating method, a roller coating method, a spraying method using a spray gun, a roll coater method, or a dipping method.

  The coating layer forming step preferably further includes a first preliminary drying step for drying the coated surface between the first coating step and the first curing step. By performing preliminary drying, an effect of volatilizing the solvent in the ultraviolet curable resin composition and preventing the inhibition of curing by the residual solvent can be obtained. The drying method is, for example, natural drying or heat drying, and heat drying is more preferable. The heating temperature is preferably 50 ° C. or higher and 90 ° C. or lower, and more preferably 60 ° C. or higher and 80 ° C. or lower. Below 50 ° C, the efficiency is poor. When it exceeds 90 degreeC, the smoothness of a coating film may be impaired. Further, depending on the material of the application object, deformation due to heat may occur. The drying time is preferably 1 minute or more and less than 20 minutes, and more preferably 2 minutes or more and 5 minutes or less. If it is less than 1 minute, the effect of preliminary drying may not be acquired. In 20 minutes or more, whitening may occur.

In the first curing step, the wavelength of the light source is preferably 200 to 450 nm. More preferably, it is 250-300 nm. The cumulative irradiation amount of ultraviolet rays is preferably 500 to 2000 mJ / cm ² . More preferably, it is 600-1200 mJ / cm < ² >. If it is less than 500 mJ / cm ² , curing may be insufficient. If it exceeds 2000 mJ / cm ² , a good mesh pattern may not be formed. In addition, whitening may occur due to overcuring, and the appearance may be inferior. The peak intensity is preferably 50 to 100 mW / cm ² . More preferably, it is 70-80 mW / cm < ² >. If it is less than 50 mW / cm ² , curing may be insufficient. When it exceeds 100 mW / cm ² , a good mesh pattern may not be formed. In addition, whitening may occur due to overcuring, and the appearance may be inferior. The irradiation time is not particularly limited because it is set according to the integrated dose and peak intensity, but as an example, it is 40 seconds when the integrated dose is 500 mJ / cm ² and the peak intensity is 50 mW / cm ^2. peak intensity in the irradiation amount 1000 mJ / cm ² is 70 seconds when 80 mW / cm ^2, integrated irradiation dose of 120 seconds when the peak intensity of 100 mW / cm ² at 2000 mJ / cm ^2.

  The size of the mesh of the mesh pattern can be adjusted by, for example, the integrated irradiation amount of ultraviolet rays or the peak intensity in addition to the type of monomer to be selected or the boiling point of the solvent. There is a tendency that the pattern becomes larger as the integrated irradiation amount of ultraviolet rays is smaller, and the pattern tends to be smaller as the integrated irradiation amount is larger. Further, the pattern tends to increase as the peak intensity decreases, and the pattern tends to decrease as the peak intensity increases. In the present embodiment, a network pattern having a desired size can be formed by adjusting the type of monomer to be selected, the boiling point of the solvent, the integrated dose of ultraviolet rays, and the peak intensity.

  In the formation method of the designable coating film which concerns on this embodiment, it is preferable to further have a metal layer formation process after an application layer formation process. Although the formation method in particular of a metal layer does not have a restriction | limiting, For example, it is a physical vapor deposition method (PVD method) or a plating method. The PVD method is, for example, ion plating, vacuum deposition, or sputtering. Examples of the plating method include an electrolytic plating method and an electroless plating method. In the present embodiment, the metal layer is more preferably formed by the PVD method in that the pattern can be made clearer.

  In the design method of the designable coating film according to this embodiment, it is preferable to further include a top coat layer forming step after the coating layer forming step or the metal layer forming step. The top coat layer forming step includes a second coating step of applying a resin composition for forming the top coat layer (hereinafter referred to as a resin composition for forming a top coat layer) to the surface of the coating layer or the metal layer, and a coating surface. A second curing step for curing.

  In the second coating step, the coating method of the topcoat layer forming resin composition is not particularly limited, and for example, the coating methods listed in the first coating step can be used.

  In the second curing step, the curing method is a matter selected depending on the material of the topcoat layer, and is, for example, ultraviolet curing or thermal curing. In the present embodiment, ultraviolet curing is more preferable. When the second curing step is performed by ultraviolet curing, various conditions such as the wavelength of the light source, the integrated irradiation amount of ultraviolet rays, the peak intensity, and the irradiation time shown in the first curing step may be employed.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this Example at all.

  Table 1 shows the types and names of the drugs used. Tables 2 to 4 show the compositions of the ultraviolet curable resin compositions of the examples and the layer structures of the design coating film. Tables 5 and 6 show the composition of the ultraviolet curable resin composition of the comparative example and the layer structure of the design coating film. In Tables 2 to 6, the names shown in Table 1 were used. Each layer was formed as follows.

(Coating layer forming process)
The coating layer was formed as follows. That is, after an ultraviolet curable resin composition is applied on an ABS plate (dimensions 10 mm × 15 mm, thickness 1 mm, model number Toughace, manufactured by Midorikawa Kasei Kogyo Co., Ltd.) by a spray coating method, the coated surface is preliminarily maintained at 60 ° C. for 3 minutes. Dried. Next, using an air-cooled mercury lamp (model number H045-L31, manufactured by Eye Graphics Co., Ltd.) as an ultraviolet light source, the ultraviolet light is irradiated for 70 seconds at an integrated irradiation amount of 1000 mJ / cm ² and a peak intensity of 80 mW / cm ² to be cured and dried. A coating layer was formed.

(Metal layer forming process)
The metal layer was formed as follows. That is, using a vacuum deposition apparatus (C-311 type vacuum deposition apparatus, Showa Vacuum Co., Ltd.) on the coating layer, tin was deposited as a metal to form a metal layer.

(Topcoat layer forming process)
The top coat layer was formed as follows. That is, a resin composition for forming a topcoat layer (VIOLET TOP T-390M-2, manufactured by Toho Kaken Kogyo Co., Ltd.) was applied on a metal layer by a spray coating method, and then the coated surface was pre-dried at 60 ° C. for 3 minutes. did. Next, using an air-cooled mercury lamp (model number H045-L31, manufactured by Eye Graphics Co., Ltd.) as an ultraviolet light source, ultraviolet rays are irradiated at an integrated irradiation amount of 1000 mJ / cm ² and a peak intensity of 80 mW / cm ² for about 1 minute to be cured and dried. A top coat layer was formed.

  The following evaluation was performed about the obtained designable coating film.

<Evaluation of mesh pattern>
Using a microscope, the surface of the design coating film is observed at a magnification of 10 times or 100 times depending on the size of the pattern, and the portion where the mesh pattern is formed is photographed. The mesh pattern was evaluated as follows. Table 7 shows the evaluation results. When the mesh pattern was not formed, no image was taken, and when the mesh pattern was not evaluated, “NA0” (practical unsuitable level) is described in Table 7.

(Mesh size)
The mesh size is obtained by dividing a captured image into a 5 mm × 5 mm square grid, and arbitrarily dividing a unit region divided into small sections by a mesh pattern from the divided 5 mm × 5 mm square region (unit region). The number of subdivisions was recorded, and the mesh size was evaluated as follows.
Extra large: The unit area is divided into 2 to 5 small sections by a mesh pattern (practical level).
Large: The unit area is divided into 6 to 20 small sections by a mesh pattern (practical level).
Medium: The unit area is divided into 21 to 40 small sections by a mesh pattern (practical level).
Small: The unit area is divided into 41 to 80 small sections by a mesh pattern (practical level).
Extremely small: The unit area is divided into 81 to 200 small sections by a mesh pattern (practical level).
NA1: There is no unit area divided into small sections by a mesh pattern (practical unsuitable level).
NA2: The unit area is divided into 201 or more subdivisions by a mesh pattern, and the visibility is inferior (practical inappropriate level).

(Average area of mesh)
For the average area of the mesh, an area of 1 cm ² was arbitrarily selected so as to include one or more meshes in the captured image, and the average area of the mesh in the area was obtained.

(Net formation rate)
As the mesh formation rate, the ratio of the number of unit areas divided into small sections by the mesh pattern to the total number of unit areas in the captured image was obtained.

(Glossy)
The glossiness was evaluated as follows.
High: A flat portion occupies more than half of the area inside the mesh (practical level).
Low: The portion where the striped pattern is formed inside the mesh occupies 3/4 or more of the area (practical level).
Middle: The portion where the striped pattern is formed in the mesh occupies more than half of the area and less than 3/4 (practical level).

<Observation of surface state and cross-sectional state>
(Coating layer)
In Example 1, the surface state of the portion where the mesh pattern after the coating layer was formed was observed obliquely from above at a magnification of 200 using a scanning electron microscope (model: JSM-5500LV, manufactured by JEOL Ltd.), and the magnification of 700 The cross-sectional state was observed from the side at double magnification. A photographed SEM image is shown in FIG. As shown in FIG. 5, fine irregularities were formed on the surface of the coating layer.

(Topcoat layer)
In Example 1, the surface state of the portion where the mesh pattern after the formation of the topcoat layer was formed was observed obliquely from above at a magnification of 800 times and the cross-sectional state from right side at a magnification of 500 times using a scanning electron microscope. . A photographed SEM image is shown in FIG. As shown in FIG. 6, the surface of the topcoat layer was smooth. By providing the top coat layer, it was confirmed that the appearance could be a highly smooth coating film having a three-dimensional mesh pattern.

<Evaluation of general performance of coating film>
About the designable coating film of Example 1 and Example 2, the general performance evaluation of the coating film was performed. The general performance evaluation of the coating film was performed as follows. The results are shown in Table 8.

(hardness)
The test was conducted according to JIS K-5600-5-4: 1999 “Scratch hardness: pencil method”. Mitsubishi UniH was used for the test. The evaluation criteria are as follows.
+: No scar was generated (practical level).
−: A scar was generated (unsuitable for practical use).

(Adhesion)
According to JIS K-5600-5-6: 1999 “Cross cut method”, 100 1 mm × 1 mm grid-like cuts were made, and a peel test was performed using an adhesive tape. Evaluation criteria were also evaluated according to the same standard.
+: 0 (practical level)
-: 1 to 5 (unsuitable for practical use)

(Abrasion resistance)
Using an RCA abrasion tester (model: 7-IBB, manufactured by NORMAN TOOL INC), contact the sand eraser with a load of 9.8 N on the surface of the coating and rub it 2000 times to visually observe the surface condition. did.
+: There is no exposure of the object to be painted (practical level)
-: The object to be coated is exposed (unsuitable for practical use)

(Cooling cycle)
After warming to 80 ° C, the temperature is decreased to -40 ° C within 5 minutes. This was defined as one cycle, and after repeating 10 cycles, the surface state of the coating film was visually confirmed.
+: No peeling or discoloration on the coating film (practical level).
-: Peeled on the coating film and has at least one of blistering or discoloration (unsuitable for practical use).

(Moisture resistance)
The member on which the coating film was formed was allowed to stand at an atmospheric temperature of 65 ° C. and an atmospheric humidity of 95% RH for 48 hours, and then the surface state of the coating film was visually confirmed.
+: No peeling or discoloration on the coating film (practical level).
-: Peeled on the coating film and has at least one of blistering or discoloration (unsuitable for practical use).

(water resistant)
The member on which the coating film was formed was immersed in warm water at 70 ° C. for 2 hours, and then the surface state of the coating film was visually confirmed.
+: No peeling or discoloration on the coating film (practical level).
-: Peeled on the coating film and has at least one of blistering or discoloration (unsuitable for practical use).

(Heat-resistant)
The member on which the coating film was formed was allowed to stand at an ambient temperature of 80 ° C. for 24 hours, and then the surface state of the coating film was visually confirmed.
+: No peeling or discoloration on the coating film (practical level).
-: Peeled on the coating film and has at least one of blistering or discoloration (unsuitable for practical use).

(Migration resistance)
The mirror mat is in close contact with the member on which the coating film is formed, and is left at an atmospheric temperature of 65 ° C. and an atmospheric humidity of 95% RH for 24 hours under a load of 4.9 N. confirmed.
+: The mirror mat is not transferred to the coating film or other appearance defects are not generated (practical level).
-: The coating film has migrated or has a defect in appearance (unsuitable for practical use).

(Weatherability)
Using a sunshine weather meter (model S80B, manufactured by Suga Test Instruments Co., Ltd.), the surface of the coating film was irradiated for 150 hours at 255 W / m ² using a carbon arc lamp as a light source, and 2.1 L / min using a shower. Water was applied continuously for 12 minutes per hour. Then, the change of the color of the coating film surface was measured using a color difference meter (model: CR-300, manufactured by Konica Minolta).
+: Color difference is 3 or less (practical level).
-: The color difference exceeds 3 (unsuitable for practical use).

  The ultraviolet curable resin compositions of Examples 1 to 20 were all photocured to form a mesh pattern. From Examples 1-7, it has confirmed that the magnitude | size of a mesh | network could be adjusted by changing the kind or compounding ratio of the acrylate-type monomer to be used. From Examples 8-17, it has confirmed that the magnitude | size of a mesh | network could be adjusted with the difference in the boiling point of the solvent to be used. Specifically, there was a tendency that the higher the boiling point of the solvent, the larger the mesh.

  Since all the ultraviolet curable resin compositions of Comparative Examples 1 to 9 used photopolymerization initiators other than benzophenone, no net pattern was formed even when photocured.

An ultraviolet curable resin composition was prepared using the acrylate monomers, acrylate oligomers, and acrylic acid oligomers shown in Tables 9 and 10. Specifically, the ultraviolet curable resin composition comprises 55 parts by mass of acrylate monomers, acrylate oligomers or acrylic acid oligomers shown in Table 9 and Table 10, 30 parts by mass of ethyl acetate, and 10 parts by mass of acetone. And 4.5 parts by mass of a benzophenone-based photopolymerization initiator and 0.5 parts by mass of a fluorine-based leveling agent (BYK340, manufactured by BYK) were prepared. The obtained ultraviolet curable resin composition was applied by spray coating on an ABS plate (dimensions 10 mm × 15 mm, thickness 1 mm, model number Taffece, manufactured by Midorikawa Kasei Kogyo Co., Ltd.), and then the coated surface was applied at 60 ° C. for 3 minutes. Pre-dried. Next, using an air-cooled mercury lamp (model number H045-L31, manufactured by Eye Graphics Co., Ltd.) as an ultraviolet light source, the ultraviolet light is irradiated for 70 seconds at an integrated irradiation amount of 1000 mJ / cm ² and a peak intensity of 80 mW / cm ² to be cured and dried. A coating layer having a thickness of 30 μm was formed. The presence or absence of the pattern and the size of the pattern were evaluated. The evaluation results are shown in Table 9 and Table 10. As shown in Table 9 and Table 10, all of the ultraviolet curable resin compositions of Reference Examples 21 to 40 were photocured to form a mesh pattern.

( Reference Example 41)
57.5 parts by mass of an acrylate oligomer (Aronix M-6500, manufactured by Toagosei Co., Ltd.), 30.8 parts by mass of ethyl acetate, 10 parts by mass of acetone, and an α-hydroxyalkylphenone photopolymerization initiator (1-hydroxy -Cyclohexyl-phenyl-ketone, Irgacure 184, manufactured by BASF) 1.2 parts by mass and a fluorine-based leveling agent (BYK340, manufactured by BYK) 0.5 parts by mass were prepared. The obtained ultraviolet curable resin composition was applied by spray coating on an ABS plate (dimensions 10 mm × 15 mm, thickness 1 mm, model number Taffece, manufactured by Midorikawa Kasei Kogyo Co., Ltd.), and then the coated surface was applied at 60 ° C. for 3 minutes. Pre-dried. Then, air-cooled mercury lamp (Model H045-L31, Eye manufactured by Graphics Inc.) as an ultraviolet light source with ultraviolet and integrated irradiation amount 1500 mJ / cm ^2, and cured and dried by irradiation for 70 seconds with a peak intensity 80 mW / cm ² A coating layer was formed. The pattern appeared and the size of the pattern was large.

( Reference Example 42)
A coating layer was formed in the same manner as in Reference Example 41 except that in Example 41, the cumulative amount of UV irradiation was changed to 2000 mJ / cm ² . The pattern appeared and the pattern size was small.

( Reference Example 43)
The coating layer was the same as in Example 1 except that the photopolymerization initiator in Example 1 was changed to a liquid aminobenzoate photopolymerization initiator (2-ethylhexyl-4-dimethylaminobenzoate, Darocur EHA, manufactured by BASF). Formed. The pattern appeared and the size of the pattern was large.

( Reference Example 44)
In Example 1, the coating layer was formed in the same manner as in Example 1 except that the photopolymerization initiator was changed to a liquid aminobenzoate-based photopolymerization initiator (ethyl-4-dimethylaminobenzoate, Darocur EDB, manufactured by BASF). did. The pattern appeared and the size of the pattern was large.

Claims (6)

(1) Ethylene oxide modified bisphenol A diacrylate, (2) Neopentyl glycol diacrylate, (3) One of dipentaerythritol hexaacrylate, ethylene oxide modified bisphenol F diacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate kind, of (1) (2) and three combinations of acrylate monomers chromatography (3),
Containing a benzophenone photopolymerization initiator as a photopolymerization initiator ,
An ultraviolet curable resin composition , wherein a coating layer having a mesh pattern formed by randomly extending concave, convex, or crack-like linear portions is formed by photocuring. The light amount of the polymerization initiator, an ultraviolet curable resin composition according to claim 1, wherein 0.5 to 40 parts by weight with respect to acrylate monomers -1 00 parts by mass. A designable coating film comprising a coating layer obtained by coating and curing the ultraviolet curable resin composition according to claim 1 or 2 on a surface of an object to be coated,
The design coating film, wherein the coating layer has a mesh pattern formed by randomly extending concave, convex, or cracked linear portions . The coating layer is divided into a 5 mm × 5 mm square grid, and at least one of the divided 5 mm × 5 mm square regions is divided into 2 to 200 small sections by the mesh pattern. The designable coating film according to claim 3 . The design coating film according to claim 3 or 4 , wherein the coating layer is an undercoat layer, and a topcoat layer is further provided on the surface of the undercoat layer. The design coating film according to any one of claims 3 to 5 , further comprising a metal layer between the undercoat layer and the topcoat layer.