Coating agent and resin member

Abstract

To provide a coating agent that enables formation of a coating film exhibiting excellent weather resistance through simple work, and a resin member having a coating film formed from the coating agent.SOLUTION: A coating agent includes a film-forming component including a component A composed of a specific silsesquioxane and a component B composed of a polymerizable compound including a specific partial structure (excluding the silsesquioxane), and a film-curing component configured to generate radicals when irradiated with ultraviolet light. The component B includes one or more compounds selected from the group consisting of a polymerizable compound (B1) having at least one cyclic structure selected from the group consisting of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle, and having a molecular weight of 300 or less, and a cyclizable polymerizable compound (B2) having a structure capable of forming a cyclic structure after polymerization and having a molecular weight of 300 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coating agent and a resin member. [Background technology]

[0002] Traditionally, inorganic materials such as steel, aluminum, and glass have been used for the components of automobiles, trains, and other vehicles. In recent years, with the aim of reducing the weight of vehicles, there has been a trend toward replacing inorganic components with organic components such as plastics. However, while organic materials are lighter than inorganic materials, they are softer and more susceptible to scratches.

[0003] Therefore, in order to improve the scratch resistance of parts made of organic materials, a technique for forming a hard coating on the surface of the part has been proposed. For example, Patent Document 1 describes a coated member having a resin substrate, a primer layer formed on the surface of the resin substrate, and a hard coat layer formed on the primer layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-240294 Summary of the Invention [Problem to be solved by the invention]

[0005] However, forming a coating consisting of a two-layer structure of a primer layer and a hard coat layer, as in the coated member of Patent Document 1, requires sequential steps of applying a primer to a resin substrate, drying the primer to form a primer layer, applying a coating agent to the primer layer, and curing the coating agent to form a hard coat layer, which makes the coating formation process complicated and increases the costs required for the coating formation process.

[0006] The present invention has been made in view of the above background, and aims to provide a coating agent that can form a coating film with excellent weather resistance through simple operations, and a resin member having a coating film formed from this coating agent. [Means for solving the problem]

[0007] One aspect of the present invention is a composition comprising a component A consisting of a silsesquioxane having a Ta structural unit represented by the following composition formula (1) and a Tc structural unit represented by the following composition formula (2); A film-forming component including a component B consisting of a polymerizable compound having a partial structure represented by the following structural formula (I) (excluding the silsesquioxane); a film-curing component configured to generate radicals when irradiated with ultraviolet light; The coating agent is characterized in that the component B comprises one or more polymerizable compounds selected from the group consisting of a polymerizable compound (B1) having at least one cyclic structure selected from the group consisting of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle, and having a molecular weight of 300 or less, and a cyclopolymerizable compound (B2) having a structure capable of forming the cyclic structure after polymerization, and having a molecular weight of 300 or less. (R 1 SiO 3 / 2 ) ···(1) (R 2 SiO 3 / 2 ) ···(2)

[0008] [ka]

[0009] However, R in the composition formula (1) 1 is an acryloyl group or a methacryloyl group, and R in the composition formula (2) 2 is a monovalent hydrocarbon group, and the symbol "*" in the structural formula (I) indicates a bond to another atom.

[0010] Another aspect of the present invention is a substrate made of a resin, a coating film formed on the substrate, The resin member has a coating film formed from a cured product of the coating agent of the above embodiment. [Effects of the Invention]

[0011] The film-forming components of the coating agent include component A, which is the specific silsesquioxane, and component B, which is a polymerizable compound. Component B also includes one or more polymerizable compounds selected from the group consisting of polymerizable compounds (B1) containing a cyclic structure and cyclopolymerizable compounds (B2) having a structure capable of forming the cyclic structure after polymerization. A coating film obtained by curing a coating agent containing these components can suppress peeling and cracking over a long period of time, even when exposed to sunlight. Therefore, the coating agent can form a coating film with excellent weather resistance.

[0012] Furthermore, the film-curing component in the coating agent is configured to generate radicals when irradiated with ultraviolet light. Furthermore, since both the A component and the B component contain the specific partial structure, the A component and the B component can be polymerized by radical polymerization by irradiating the coating agent with ultraviolet light to generate radicals from the film-curing component. Therefore, the coating agent can form a coating film by a simple method.

[0013] Therefore, according to the above-described aspect, it is possible to provide a coating agent that can form a coating film with excellent weather resistance through simple operations, and a resin member having a coating film formed from this coating agent. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an explanatory diagram showing the evaluation results of the weather resistance of test agents 1 to 6 in the examples. [Figure 2] FIG. 2 is an explanatory diagram showing the evaluation results of the weather resistance of test agents 9 to 12 in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0015] (coating agent) The coating agent contains a film-forming component that forms a coating film by curing, and a film-hardening component that hardens the film-forming component. The composition of each component contained in the coating agent will be described below.

[0016] [Film forming component] The film-forming components include a component A made of silsesquioxane and a component B made of a polymerizable compound having a specific partial structure.

[0017] Component A Component A in the film-forming components is composed of silsesquioxane. Component A forms an inorganic component derived from silsesquioxane in the coating film, and has the effect of improving the durability of the coating film against scratches. Component A may be composed of one type of silsesquioxane, or may be composed of two or more types of silsesquioxanes having different structures. The silsesquioxane constituting component A has a Ta structural unit represented by the following composition formula (1) and a Tc structural unit represented by the following composition formula (2). (R 1 SiO 3 / 2 ) ···(1) (R 2 SiO 3 / 2 ) ···(2)

[0018] However, R in the composition formula (1) 1 is an acryloyl group or a methacryloyl group, and R in the composition formula (2) 2 is a monovalent hydrocarbon group. 2More specifically, R may be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, etc. From the viewpoint of more reliably obtaining the above-mentioned effects, R in the composition formula (2) 2 is preferably a monovalent saturated hydrocarbon group, more preferably a saturated hydrocarbon group having 18 or less carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0019] The (meth)acryloyl group in the silsesquioxane can be polymerized together with the partial structure in the polymerizable compound constituting the component B by radicals generated from the film-curing component.

[0020] The molar ratio of the content of Ta structural units to the total content of Ta structural units and Tc structural units in the silsesquioxane may be, for example, more than 0 mol% and not more than 60 mol%. The weight-average molecular weight of the silsesquioxane may be 2,000 or more. In this case, a coating film having excellent adhesion to the substrate and excellent scratch resistance can be easily formed.

[0021] The content of Ta structural units in silsesquioxane is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, particularly preferably 20 mol% or more, and most preferably 25 mol% or more, based on the total content of Ta structural units and Tc structural units. In this case, the abrasion resistance of the coating film can be further improved.

[0022] When determining a preferred range of the content of the Ta structural unit in the silsesquioxane, the upper and lower limits of the content of the Ta structural unit described above can be combined arbitrarily. For example, the preferred range of the content of the Ta structural unit in the silsesquioxane may be 5 mol% to 60 mol%, 10 mol% to 60 mol%, 15 mol% to 60 mol%, 20 mol% to 60 mol%, or 25 mol% to 60 mol%, based on the total content of the Ta structural unit and the Tc structural unit.

[0023] The weight-average molecular weight of the silsesquioxane is preferably 2,500 or more, more preferably 3,000 or more, even more preferably 3,500 or more, and particularly preferably 4,000 or more. In this case, the adhesion between the coating film and the substrate and the durability against scratches can be improved.

[0024] On the other hand, if the weight-average molecular weight of the silsesquioxane is too large, the viscosity of the coating agent will increase excessively, which may lead to deterioration of workability in applying the coating agent. From the viewpoint of avoiding such problems, the weight-average molecular weight of the silsesquioxane is preferably 25,000 or less, more preferably 20,000 or less, even more preferably 15,000 or less, and particularly preferably 13,000 or less.

[0025] When constituting the preferred range of the weight-average molecular weight of the silsesquioxane, the upper limit and the lower limit of the weight-average molecular weight of the silsesquioxane described above can be arbitrarily combined.For example, the preferred range of the weight-average molecular weight of the silsesquioxane may be 2,000 or more and 25,000 or less, 2,000 or more and 20,000 or less, 2,500 or more and 15,000 or less, 3,000 or more and 15,000 or less, 4,000 or more and 15,000 or less, or 4,000 or more and 13,000 or less.

[0026] The silsesquioxane may further contain a Q structural unit represented by the following composition formula (4): In this case, the molar ratio of the content of the Q structural unit to the total content of the Ta structural unit, the Tc structural unit, and the Q structural unit in the silsesquioxane is preferably more than 0 mol% and not more than 25 mol%. (SiO 4 / 2 ) ···(4)

[0027] By introducing Q structural units into silsesquioxane, the abrasion resistance of the coating film can be further improved. From the viewpoint of improving the abrasion resistance of the coating film, the content of Q structural units in silsesquioxane is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 3 mol% or more, based on the total content of Ta structural units, Tc structural units, and Q structural units.

[0028] On the other hand, if the content of Q structural units in the silsesquioxane is excessively high, silsesquioxane aggregates are likely to form in the coating film, which may lead to a deterioration in the appearance of the coating film, a decrease in abrasion resistance, etc. These problems can be easily avoided by setting the content of Q structural units in the silsesquioxane to preferably 25 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less, particularly preferably 10 mol% or less, and most preferably 8 mol% or less, based on the total content of Ta structural units, Tc structural units, and Q structural units.

[0029] When determining a preferred range for the content of the Q structural unit in the silsesquioxane, the upper and lower limits of the content of the Q structural unit described above can be combined arbitrarily. For example, a preferred range for the content of the Q structural unit in the silsesquioxane may be 1 mol% to 20 mol% or less, 1 mol% to 15 mol%, 2 mol% to 10 mol%, 2 mol% to 8 mol%, or 3 mol% to 8 mol% of the total content of the Ta structural unit, the Tc structural unit, and the Q structural unit.

[0030] The content of Component A in the coating agent is preferably 20 to 150 parts by mass, more preferably 30 to 150 parts by mass, even more preferably 40 to 125 parts by mass, and particularly preferably 50 to 100 parts by mass, per 100 parts by mass of Component B. In this case, the scratch resistance of the coating film and the adhesion to the substrate can be improved in a better balance.

[0031] The silsesquioxane used in the coating agent can be obtained, for example, by condensing a plurality of alkoxysilanes including a (meth)acryloxyalkyltrialkoxysilane that forms a Ta structural unit and an alkyltrialkoxysilane that forms a Tc structural unit.

[0032] Examples of (meth)acryloxyalkyltrialkoxysilanes that can be used as Ta structural units include 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane. These (meth)acryloxyalkyltrialkoxysilanes may be used alone to synthesize silsesquioxanes. Alternatively, two or more (meth)acryloxyalkyltrialkoxysilanes may be used in combination to synthesize silsesquioxanes.

[0033] Examples of alkyltrialkoxysilanes that can be used as Tc structural units include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, isopropyltriethoxysilane, and n-butyltriethoxysilane. These alkyltrialkoxysilanes may be used alone to synthesize silsesquioxanes. Alternatively, two or more alkyltrialkoxysilanes may be used in combination to synthesize silsesquioxanes.

[0034] When introducing a Q structural unit into a silsesquioxane, the silsesquioxane can be synthesized using a tetraalkoxysilane in addition to the trialkoxysilane described above. As the tetraalkoxysilane that forms the Q structural unit, for example, tetramethoxysilane, tetraethoxysilane, etc. can be used. These tetraalkoxysilanes may be used alone to synthesize the silsesquioxane. Alternatively, two or more types of tetraalkoxysilanes can be used in combination to synthesize the silsesquioxane.

[0035] The reaction conditions for synthesizing silsesquioxane using alkoxysilane are not particularly limited, and the alkoxysilane may be condensed by a known method.

[0036] ·B component Component B in the film-forming components is composed of a polymerizable compound having a partial structure represented by the following structural formula (I). Note that the symbol "*" in the following structural formula (I) indicates a bond to another atom. Also, the silsesquioxane is excluded from component B.

[0037] [ka]

[0038] The partial structure in the polymerizable compound undergoes radical polymerization due to radicals generated from the film-curing component. This allows an organic component to be formed in the coating film. By forming an organic component in the coating film in this way, the adhesion between the coating film and the substrate can be improved. Furthermore, the partial structure in the polymerizable compound can react with a (meth)acryloyl group contained in component A to bond component B and component A.

[0039] Component B contains at least one or more polymerizable compounds selected from the group consisting of polymerizable compounds (B1) having a cyclic structure and a molecular weight of 300 or less, and cyclopolymerizable compounds (B2) having a structure capable of forming a cyclic structure after polymerization and a molecular weight of 300 or less. These polymerizable compounds (B1) and cyclopolymerizable compounds (B2) have the effect of improving the weather resistance of the coating film.

[0040] The partial structure contained in component B may be contained, for example, as a vinyl group in the molecular structure of the polymerizable compound, or may be contained as part of a functional group having a polymerizable unsaturated bond, such as a methacryloyl group or an acryloyl group.

[0041] The cyclic structure contained in the polymerizable compound (B1) may be any one of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle. In this specification, an alicyclic structure refers to a structure composed of cyclic hydrocarbons that do not have aromaticity. The alicyclic structure may be composed of saturated cyclic hydrocarbons or unsaturated cyclic hydrocarbons. Examples of the alicyclic structure include structures contained in cycloalkyl groups such as cyclopentyl groups, cyclohexyl groups, isobornyl groups, and dicyclopentanyl groups, and structures contained in cycloalkenyl groups such as dicyclopentenyl groups.

[0042] In this specification, the term "aromatic hydrocarbon ring" refers to a structure composed of cyclic hydrocarbons having aromaticity. Examples of aromatic hydrocarbon rings include structures contained in aromatic hydrocarbon groups such as benzyl groups and naphthyl groups. In this specification, the term "saturated heterocycle" refers to a structure composed of cyclic saturated hydrocarbons containing one or more heteroatoms. Examples of saturated heterocycles include cyclic ether structures contained in tetrahydrofurfuryl groups, dioxolane groups, etc., cyclic lactam structures contained in pyrrolidones, etc., and cyclic amine structures contained in morpholino groups, etc.

[0043] More specifically, examples of the polymerizable compound (B1) having an alicyclic structure include (meth)acrylic acid esters having a cycloalkyl group, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; and (meth)acrylic acid esters having a cycloalkenyl group, such as dicyclopentenyl (meth)acrylate and 2-(dicyclopentenyloxy)ethyl (meth)acrylate.

[0044] Examples of the polymerizable compound (B1) having an aromatic hydrocarbon ring include (meth)acrylic acid esters having an aromatic hydrocarbon group, such as phenoxyethyl (meth)acrylate. Examples of the polymerizable compound (B1) having a saturated heterocycle include (meth)acrylic acid esters having a cyclic ether group, such as tetrahydrofurfuryl (meth)acrylate and (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate; (meth)acrylic acid esters having a cyclic amine group, such as 4-acryloyl (meth)morpholine; and vinyl compounds having a cyclic lactam group, such as N-vinyl-2-pyrrolidone.

[0045] The cyclopolymerizable compound (B2) has a molecular structure that can form the above-mentioned cyclic structure after polymerization. As the cyclopolymerizable compound (B2), for example, a compound having two of the above partial structures in its molecular structure can be used. From the viewpoint of further increasing the cyclization rate, the cyclopolymerizable compound (B2) preferably has a 1,6-diene structure, that is, a structure in which, when the terminal carbon of the first partial structure of the two partial structures is the carbon at the 1st position, the second partial structure is composed of the carbons at the 6th and 7th positions.

[0046] The coating agent preferably contains a cyclopolymerizable compound (B2) as component B. A coating agent containing the cyclopolymerizable compound (B2) can easily form a coating film with high optical uniformity. Therefore, for example, when a coating film made of the coating is formed on a transparent substrate, distortion of the transmitted image can be reduced, and a resin glass with good optical properties can be easily obtained. Therefore, a coating agent containing the cyclopolymerizable compound (B2) can be suitably used to form a clear coat or a hard coat for resin glass.

[0047] In order to more reliably obtain the effect of improving the optical uniformity of the coating film, it is preferable that the cyclopolymerizable compound (B2) has an ether bond in its molecular structure. From the same viewpoint, it is preferable that the cyclopolymerizable compound (B2) has 2-(allyloxymethyl)methyl acrylate, that is, a molecular structure represented by the following structural formula (II):

[0048] [ka]

[0049] Furthermore, from the viewpoint of more reliably obtaining the above-mentioned effects, the content of the cyclopolymerizable compound (B2) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the B component.

[0050] On the other hand, the content of the cyclopolymerizable compound (B2) is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less, per 100 parts by mass of the B component.

[0051] The preferred range of the content of the cyclopolymerizable compound (B2) in component B can be determined by any combination of the above-mentioned upper and lower limits of the content of the cyclopolymerizable compound (B2). For example, the preferred range of the cyclopolymerizable compound (B2) per 100 parts by mass of component B may be 5 to 50 parts by mass, 7 to 50 parts by mass, 10 to 50 parts by mass, 15 to 50 parts by mass, 15 to 40 parts by mass, or 15 to 35 parts by mass.

[0052] In addition to the polymerizable compound (B1) and cyclopolymerizable compound (B2), component B may also contain a polymerizable compound (B3) having a structure different from these. Examples of the polymerizable compound (B3) include (meth)acrylic acid esters that do not have a cyclic structure and are not cyclopolymerizable. More specifically, examples of the polymerizable compound (B3) that can be used include (meth)acrylic acid monoesters such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, 1-methylethyl(meth)acrylate, butyl(meth)acrylate, 2-methylpropyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, and 2-hydroxypropyl(meth)acrylate; (meth)acrylic acid diesters such as 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and isocyanuric acid ethylene oxide-modified di(meth)acrylate; and (meth)acrylic acid esters having three or more (meth)acryloyl groups such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and isocyanuric acid ethylene oxide-modified tri(meth)acrylate. The (meth)acrylate may be a monomer of the above-mentioned compound, or may be an oligomer obtained by polymerizing a plurality of monomers in advance.

[0053] The polymerizable compound (B3) preferably has three or more (meth)acryloyl groups per molecule. In this case, the structural units derived from component B and the structural units derived from silsesquioxane can be polymerized in a network form via the polymerizable compound (B3). As a result, the surface hardness of the coating film can be further increased, and its durability against scratches can be further improved. From the viewpoint of further improving weather resistance, the polymerizable compound (B3) preferably has an isocyanuric ring.

[0054] From the viewpoint of more reliably obtaining the effect of improving the optical uniformity of the coating film, it is preferable that Component B contains a cyclopolymerizable compound (B2) and a polymerizable compound (B3). In this case, the content of cyclopolymerizable compound (B2) is preferably 5 to 50 parts by mass, more preferably 7 to 50 parts by mass, even more preferably 10 to 50 parts by mass, and particularly preferably 15 to 50 parts by mass, per 100 parts by mass of Component B.

[0055] ·C component The film-forming component may further contain component C, which is silica particles having a volumetric median diameter of 5 nm to 300 nm. By incorporating component C into the film-forming component, the surface hardness of the coating film can be further increased, and its durability against scratches can be further improved.

[0056] As component C, for example, colloidal silica or surface-modified colloidal silica obtained by chemically modifying the surface of colloidal silica can be used. The surface of the silica particles constituting component C is preferably modified with a polyorganosiloxane group. By modifying the surface of the silica particles with a polyorganosiloxane group, it is expected that the dispersion stability of the silica particles in the coating agent can be further improved. Furthermore, the improved dispersion stability of the silica particles makes it easier to form a coating film with desired properties.

[0057] The surfaces of the silica particles may be modified only with polyorganosiloxane groups, or may be modified with polyorganosiloxane groups and functional groups other than polyorganosiloxane groups.

[0058] The content of Component C is preferably 0.5 to 50 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 5 to 50 parts by mass, particularly preferably 10 to 50 parts by mass, and most preferably 15 to 50 parts by mass, per 100 parts by mass of Component B. In this case, the surface hardness of the coating film can be further increased.

[0059] [Film curing component] The coating agent contains a film-curing component for promoting the curing reaction of the film-forming component. The film-curing component is configured to generate radicals when irradiated with ultraviolet light. Therefore, by irradiating the coating agent with ultraviolet light, the (meth)acryloyl group in component A and the partial structure in component B are polymerized by radical polymerization, forming a coating film.

[0060] The film-curing component may be configured to generate both a base and a radical when irradiated with ultraviolet light. The base generated from the film-curing component can condense silsesquioxane through a sol-gel reaction. Therefore, in this case, by irradiating the coating agent with ultraviolet light, radical polymerization and a sol-gel reaction can proceed in parallel to form a coating film.

[0061] Furthermore, by allowing radical polymerization and sol-gel reaction to proceed in parallel during the curing process of the coating film, it is expected that adhesion to the substrate will be further improved.

[0062] The film-curing component may be, for example, a photoradical polymerization initiator configured to generate radicals when irradiated with ultraviolet light, or a photobase generator configured to generate both radicals and a base when irradiated with ultraviolet light. Furthermore, the film-curing component may contain, as needed, a photobase generator configured to generate both radicals and a base when irradiated with ultraviolet light.

[0063] Examples of the photoradical polymerization initiator that can be used include acetophenone compounds, benzophenone compounds, α-ketoester compounds, phosphine oxide compounds, benzoin compounds, titanocene compounds, acetophenone / benzophenone hybrid photoinitiators, oxime ester photoinitiators, and camphorquinone.

[0064] Examples of acetophenone compounds include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, diethoxyacetophenone, oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one.

[0065] Examples of benzophenone compounds include benzophenone, 4-phenylbenzophenone, 2,4,6-trimethylbenzophenone, and 4-benzoyl-4'-methyldiphenyl sulfide. Examples of α-ketoester compounds include methylbenzoyl formate, 2-(2-oxo-2-phenylacetoxyethoxy)ethyl ester of oxyphenylacetic acid, and 2-(2-hydroxyethoxy)ethyl ester of oxyphenylacetic acid.

[0066] Examples of phosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. Examples of acetophenone / benzophenone hybrid photoinitiators include 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfinyl)propan-1-one. Examples of oxime ester photopolymerization initiators include 2-(O-benzoyloxime)-1-[4-(phenylthio)]-1,2-octanedione.

[0067] The film-curing component may contain one type of photoradical polymerization initiator, or may contain two or more types of photoradical polymerization initiators.

[0068] As the photobase generator, a compound can be used that has an ultraviolet light absorbing moiety that contains an aromatic ring such as a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, an anthraquinone ring, a xanthene ring, or a thioxanthene ring in its molecular structure and absorbs ultraviolet light, and a base moiety that contains a structural unit that becomes a base when released from the ultraviolet light absorbing moiety, such as a primary to tertiary amino group, a quaternary ammonium cation, a carbamoyl group, a carbamate bond, an imino bond, or a nitrogen-containing heterocycle, and is bonded to the ultraviolet light absorbing moiety.

[0069] Examples of such compounds include 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate, (Z)-{[bis(dimethylamino)methylidene]amino}-N-cyclohexyl(cyclohexylamino)methaniminium tetrakis(3-fluorophenyl)borate, 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidinium 2-(3-benzoylphenyl)propionate, 9-anthrylmethyl N,N-diethylcarbamate, (E)-1-piperidino-3-(2-hydroxyphenyl)-2-propen-1-one, and imidazole-1-carboxylic acid 1-carboxylate. -(anthraquinone-2-yl)ethyl, 4-(methacryloyloxy)piperidine-1-carboxylate (2-nitrophenyl)methyl, 1,2-bis(4-methoxyphenyl)-2-oxoethyl cyclohexylcarbamate, 2-nitrobenzyl cyclohexylcarbamate, 2-(9-oxoxanthen-2-yl)propionic acid 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 2-(9-oxoxanthen-2-yl)propionic acid 1,5-diazabicyclo[4.3.0]non-5-ene, 2-(9-oxoxanthen-2-yl)propionic acid 1,8-diazabicyclo[5.4.0]undec-7-ene, acetophenone O-benzoyloxime, 2-(piperidine-1-carbonyl)benzaldehyde, nifedipine, and the like.

[0070] The film-curing component may contain one type of photobase generator, or may contain two or more types of photobase generators.

[0071] The content of the film-hardening component in the coating agent may be appropriately set depending on the composition of the film-hardening component, etc. For example, the content of the film-hardening component in the coating agent may be appropriately set within the range of 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the film-forming component.

[0072] [Other additives] In addition to the film-forming component and the film-curing component, the coating agent may contain additives known for use in coating agents, provided that the curing of the coating agent is not impaired. For example, the coating agent may contain additives for suppressing deterioration of the coating film, such as an ultraviolet absorber, a radical scavenger, or a hindered amine light stabilizer. The use of these additives can be expected to have the effect of improving the weather resistance of the coating film.

[0073] The coating agent may also contain additives such as surface conditioners, such as leveling agents and defoaming agents. The use of these additives can ensure a uniform thickness of the coating agent when applied to a substrate. As a result, the resin member provided with the coating film can be expected to have improved scratch resistance.

[0074] (Resin parts) The coating agent can be applied to a substrate made of resin and then cured to obtain a resin part. That is, the resin part has a substrate made of resin and a coating film made of the cured product of the coating agent that covers the surface of the substrate.

[0075] The resin constituting the substrate can be appropriately selected depending on the application of the resin member. For example, when the resin member is used as a transparent window member, polycarbonate can be used as the substrate. Polycarbonate has excellent properties required for transparent window members, such as weather resistance, strength, and transparency. Furthermore, the coating film obtained by curing the coating agent is transparent, so that scratch resistance can be improved without impairing the transparency of the polycarbonate. Furthermore, as described above, the coating film obtained by curing the coating agent has excellent weather resistance and can suppress peeling and cracking over a long period of time even when exposed to sunlight. Therefore, by forming the transparent coating film on a substrate made of polycarbonate, a resin member suitable for use as a transparent window member can be obtained.

[0076] The coating film preferably has a surface layer exposed on the surface of the resin member and an inner layer interposed between the surface layer and the substrate, and the average concentration of Si atoms in the surface layer is higher than the average concentration of Si atoms in the inner layer. The surface layer of the coating film is mainly composed of inorganic components derived from silsesquioxane. Therefore, by forming a surface layer composed of inorganic components, the surface hardness of the coating film can be further increased.

[0077] Furthermore, the inner layer of the coating film is mainly composed of organic components derived from polymerizable compounds. Therefore, by forming an inner layer composed of organic components between the surface layer and the substrate, the toughness of the coating film can be increased and the adhesion between the substrate and the coating film can be further improved. Therefore, by forming a coating film having a two-layer structure consisting of an inner layer and a surface layer on the substrate, it is possible to improve scratch resistance and weather resistance.

[0078] (Method of manufacturing resin member) In producing the resin member, a coating agent is first applied to the surface of a substrate. The method for applying the coating agent to the substrate is not particularly limited, and an appropriate method may be selected from known application methods depending on the desired film thickness, etc. For example, known application devices such as a spray coater, flow coater, spin coater, dip coater, bar coater, inkjet coater, and applicator can be used to apply the coating agent to the substrate.

[0079] After the coating agent is applied to the surface of the substrate, a step of heating and drying the coating agent may be carried out as necessary.

[0080] After applying the coating agent to the surface of the substrate, the coating agent is cured by irradiating it with ultraviolet light. As mentioned above, when the coating agent is irradiated with ultraviolet light, radicals are generated from the film-curing component. The radicals generated from the film-curing component then polymerize components A and B, forming a coating film on the substrate consisting of the cured product of the coating agent.

[0081] For the irradiation of ultraviolet light, an appropriate light source can be selected and used from known light sources capable of generating ultraviolet light, such as a mercury lamp, a metal halide lamp, a light-emitting diode, an excimer lamp, etc., depending on the absorption wavelength of the film curing component, the required light amount, etc. When irradiating with ultraviolet light, the ultraviolet light may be irradiated in an air atmosphere or a nitrogen atmosphere.

[0082] In the manufacturing method, if necessary, the resin member may be heated after forming the coating film on the substrate. The coating film cured by irradiation with ultraviolet light contains unreacted hydroxyl groups, alkoxy groups, and (meth)acryloyl groups. Therefore, by heating the resin member, the unreacted hydroxyl groups, alkoxy groups, and (meth)acryloyl groups react, further promoting the curing of the coating film and further improving the scratch resistance of the coating film. [Example]

[0083] An example of the coating agent will be described. The coating agent of this example includes a film-forming component including a component A consisting of a silsesquioxane having a Ta structural unit represented by the following composition formula (1) and a Tc structural unit represented by the following composition formula (2), a component B consisting of a polymerizable compound (excluding the silsesquioxane) having a partial structure represented by the following composition formula (I), and a film-curing component configured to generate radicals when irradiated with ultraviolet light. Component B includes one or more compounds selected from the group consisting of a polymerizable compound (B1) having at least one cyclic structure selected from the group consisting of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle, and having a molecular weight of 300 or less, and a cyclopolymerizable compound (B2) having a structure capable of forming a cyclic structure after polymerization, and having a molecular weight of 300 or less. (R 1 SiO 3 / 2 ) ···(1) (R 2 SiO 3 / 2 ) ···(2)

[0084] [ka]

[0085] However, R in the composition formula (1) 1 is an acryloyl group or a methacryloyl group, and R in the composition formula (2) 2 is a monovalent hydrocarbon group, and the symbol "*" in the structural formula (I) indicates a bond to another atom.

[0086] The components A and B used in the coating agent of this example are as follows:

[0087] (Component A) Silsesquioxane A1: condensation product of methacryloxypropyltrimethoxysilane, methyltriethoxysilane, and tetraethoxysilane, Ta structural unit content: 38 mol%, Tc structural unit content: 57 mol%, Q structural unit content: 5 mol%, weight average molecular weight: 10,000 Silsesquioxane A2: condensation product of methacryloxypropyltrimethoxysilane and methyltriethoxysilane, Ta structural unit content: 30 mol%, Tc structural unit content: 70 mol%, weight average molecular weight: 5,000 Silsesquioxane A3: condensation product of methacryloxypropyltriethoxysilane and methyltriethoxysilane, Ta structural unit content: 50 mol%, Tc structural unit content: 50 mol%, weight average molecular weight: 5,000

[0088] The condensation of the silane compounds was carried out by a known method. The weight average molecular weights of the silsesquioxanes A1 to A3 were calculated by gel permeation chromatography using polystyrene as a standard substance.

[0089] (B component) [Polymerizable compound (B1) having a cyclic structure] Polymerizable compound B1-1: tetrahydrofurfuryl acrylate Polymerizable compound B1-2: Isobornyl acrylate Polymerizable compound B1-3: Dicyclopentanyl acrylate Polymerizable compound B1-4: cyclohexyl acrylate Polymerizable compound B1-5: Dicyclopentenyl acrylate Polymerizable compound B1-6: Dicyclopentenyloxyethyl acrylate

[0090] [Cyclopolymerizable compound (B2)] Cyclopolymerizable compound B2-1: 2-(allyloxymethyl)methyl acrylate

[0091] [Polymerizable compound (B3)] Polymerizable compound B3-1: a mixture containing ethylene oxide isocyanurate-modified triacrylate ("M-315" manufactured by Toagosei Co., Ltd.)

[0092] The compounds described above were dissolved in a solvent containing an ether as the main component in the ratios shown in Tables 1 to 3, and a photoradical polymerization initiator (specifically, an acylphosphine oxide-based photoradical polymerization initiator and an intramolecular hydrogen abstraction-type photoradical polymerization initiator) and a photobase generator were dissolved in the solvent as film-curing components, to obtain test agents 1 to 5 shown in Table 1, test agents 7 and 9 to 11 shown in Table 2, and test agents 13 to 19 shown in Table 3. Test agent 6 shown in Table 1 is a test agent for comparison with test agents 1 to 5. Similarly, test agent 8 shown in Table 2 is a test agent for comparison with test agent 7, and test agent 12 is a test agent for comparison with test agents 9 to 11.

[0093] In this example, resin parts were prepared using the test agents shown in Tables 1 to 3, and the weather resistance and appearance of the obtained resin parts were evaluated. The method for preparing the resin parts, the method for evaluating the weather resistance, and the method for evaluating the appearance are as follows.

[0094] (Method for manufacturing resin components) A 5 mm thick substrate made of polycarbonate resin was prepared, and one of test agents 1 to 19 was applied to the surface of the substrate using a bar coater. After the test agent was applied to the substrate, the substrate was pre-baked by heating it for 3 minutes in a hot air drying oven set at a temperature of 100°C.

[0095] After pre-baking, the test agent was irradiated with ultraviolet light to form a coating film made of the cured product of the test agent on the surface of the substrate. In this example, the ultraviolet light irradiation was carried out in a nitrogen atmosphere. A high-pressure mercury lamp was used as the source of the ultraviolet light. The illuminance of the ultraviolet light was 250 mW / cm. 2 The exposure dose was 2500 mJ / cm 2 It was decided.

[0096] After irradiation with ultraviolet light, the coating film was post-baked by heating for 10 minutes in a hot air drying oven set at 130°C. This resulted in a resin part. The resulting resin part was colorless and transparent.

[0097] Furthermore, cross sections of the coating films obtained by curing Test Agents 1 to 5, 7, 9 to 11, and 13 to 19 were observed using a scanning secondary electron microscope equipped with an energy dispersive X-ray analyzer (i.e., SEM-EDX) to obtain mapping images of silicon atoms in the cross sections. These coating films had a two-layer structure consisting of a surface layer exposed on the surface of the resin member and an inner layer interposed between the surface layer and the substrate. Furthermore, the average concentration of Si atoms in the surface layer was higher than that in the inner layer.

[0098] (weather resistance) Accelerated weathering tests were conducted using an ultra-accelerated weathering tester ("Metal Weather (registered trademark)" manufactured by Daipla Wintes Co., Ltd.). In the accelerated weathering test, one cycle consisted of a step of irradiating the resin part with ultraviolet light generated from a metal halide lamp and a step of pausing irradiation and allowing the resin part to condense, and this cycle was repeated. Weathering resistance was evaluated based on the number of cycles until cracks appeared in the coating film and the number of cycles until the coating film peeled off from the substrate.

[0099] The presence or absence of peeling of the coating film was evaluated based on the results of an adhesion test in accordance with the provisions of JIS K5600-5-6:1999 (ISO 2409:1992). The presence or absence of cracks in the coating film was evaluated visually. The "Peeling" column in Tables 1 to 3 indicates the number of cycles required until the coating film peeled from the substrate, and the "Crack" column indicates the number of cycles required until cracks appeared in the coating film. When multiple tests were conducted on the same test agent, the arithmetic mean values ​​of the number of cycles obtained in these tests are shown in the "Peeling" and "Crack" columns. In these columns, values ​​preceded by the symbol ">" indicate that no peeling or cracking of the coating film occurred up to that cycle.

[0100] Furthermore, Figure 1 shows the evaluation results of the weather resistance of test agents 1 to 6, and Figure 2 shows the evaluation results of the weather resistance of test agents 9 to 12. The vertical axis of Figures 1 and 2 represents the number of cycles (unit: cycles) until peeling or cracking of the coating film occurs, and the horizontal axis represents the content (unit: parts by mass) of cyclopolymerizable compound (B2) per 100 parts by mass of component B.

[0101] 〔exterior〕 When an object was projected onto the coating film of the resin member, the reflected image was visually observed and evaluated for distortion. If the reflected image was not distorted, it was recorded as "Good" in the "Appearance" column of Tables 1 to 3, and if the reflected image was distorted, it was recorded as "Poor" in the same column.

[0102] [Table 1]

[0103] [Table 2]

[0104] [Table 3]

[0105] As shown in Table 1, the film-forming components of Test Agents 1 to 5 contain silsesquioxane A1 as Component A and cyclopolymerizable compound (B2) as Component B. Therefore, as shown in Table 1 and Figure 1, Test Agents 1 to 5 were able to achieve a greater number of cycles before peeling or cracking occurred in the coating film compared to Test Agent 6, which had the same composition as Test Agents 1 to 5 except that it did not contain Component B.

[0106] Similarly, when comparing test agents containing silsesquioxane A2, as shown in Table 2, test agent 7, which contains component B, was able to increase the number of cycles until peeling or cracking occurred in the coating film compared to test agent 8, which had the same composition as test agent 7 except that it did not contain component B. Furthermore, when comparing test agents containing silsesquioxane A3, as shown in Table 2 and Figure 2, test agents 9 to 11, which contain component B, were able to increase the number of cycles until peeling or cracking occurred in the coating film compared to test agent 12, which had the same composition as test agents 9 to 11 except that it did not contain component B.

[0107] Furthermore, as shown in Table 3, the number of cycles until peeling or cracking occurred in the coating film of test agents 14 to 19 containing polymerizable compound B1 having a cyclic structure was equal to or greater than that of test agent 13 containing cyclic polymerizable compound (B2).

[0108] Therefore, these results show that a coating film with excellent weather resistance can be formed by curing the coating agent, and that the coating film can be formed by the simple process of applying the coating agent to a substrate and then irradiating it with ultraviolet light.

[0109] Furthermore, from the comparison of test agents 13 to 19 shown in Table 3, it can be seen that the use of the cyclopolymerizable compound (B2) as component B improves the optical uniformity of the coating film and results in a resin part with less distortion of reflected and transmitted images.

[0110] Although the embodiments of the coating agent and resin member have been described above based on the examples, the specific embodiments of the coating agent and resin member according to the present invention are not limited to those of the examples, and the configurations can be appropriately changed within the scope of the present invention. For example, in the examples, an example of a coating agent consisting of component A, component B, a film-hardening component, and a solvent has been described, but the coating agent can also contain component C consisting of silica particles and other additives as needed.

[0111] The coating agent according to the present invention may take the following aspects [1] to

[13] .

[0112] [1] A component A consisting of a silsesquioxane having a Ta structural unit represented by the following composition formula (1) and a Tc structural unit represented by the following composition formula (2), A film-forming component including a component B consisting of a polymerizable compound having a partial structure represented by the following structural formula (I) (excluding the silsesquioxane); a film-curing component configured to generate radicals when irradiated with ultraviolet light; The coating agent, wherein the component B comprises one or more compounds selected from the group consisting of a polymerizable compound (B1) having at least one cyclic structure selected from the group consisting of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle, and having a molecular weight of 300 or less, and a cyclopolymerizable compound (B2) having a structure capable of forming a cyclic structure after polymerization, and having a molecular weight of 300 or less. (R 1 SiO 3 / 2 ) ···(1) (R 2 SiO 3 / 2 ) ···(2)

[0113] [ka]

[0114] (However, R in the composition formula (1) 1 is an acryloyl group or a methacryloyl group, and R in the composition formula (2) 2 is a monovalent hydrocarbon group, and the symbol "*" in the structural formula (I) indicates a bond to another atom.

[0115] [2] The coating agent according to [1], wherein the cyclopolymerizable compound (B2) has two of the partial structures in its molecular structure. [3] The coating agent according to [2], wherein the cyclopolymerizable compound (B2) has a 1,6-diene structure. [4] The coating agent according to any one of [1] to [3], wherein the cyclopolymerizable compound (B2) has an ether bond in its molecular structure.

[0116] [5] The coating agent according to [1], wherein the cyclopolymerizable compound (B2) is a compound represented by the following structural formula (II):

[0117] [ka]

[0118] [6] The coating agent according to any one of [1] to [6], wherein the component B comprises the cyclopolymerizable compound (B2). [7] The coating agent according to [6], wherein the content of the cyclopolymerizable compound (B2) is 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the component B. [8] The coating agent according to any one of [1] to [7], wherein the silsesquioxane further contains a Q structural unit represented by the following composition formula (4): (SiO 4 / 2 ) ···(4)

[0119] [9] The coating agent according to any one of [1] to [9], wherein the content of the component A is 20 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the component B.

[10] The coating agent according to any one of [1] to

[10] , wherein the film-forming component further contains a component C consisting of silica particles having a volume-based median diameter of 5 nm or more and 300 nm or less.

[11] The coating agent according to

[10] , wherein the surface of the silica particles is modified with a polyorganosiloxane group.

[12] The coating agent according to

[10] or

[11] , wherein the content of the C component is 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the B component.

[13] The coating agent according to any one of [1] to

[12] , wherein the film-curing component is configured to be capable of generating both radicals and bases when irradiated with ultraviolet light.

[0120] The resin member according to the present invention may take the following forms

[14] to

[16] .

[0121]

[14] A substrate made of resin; A resin member comprising a coating film made of a cured product of the coating agent according to any one of [1] to

[13] , and covering the surface of the substrate.

[15] The resin member according to

[14] , wherein the substrate is made of polycarbonate.

[16] The resin member according to

[14] or

[15] , wherein the coating film has a surface layer exposed on the surface of the resin member and an inner layer interposed between the surface layer and the substrate, and the average concentration of Si atoms in the surface layer is higher than the average concentration of Si atoms in the inner layer.

Claims

1. A component A is composed of a silsesquioxane having a Ta structural unit represented by the following composition formula (1) and a Tc structural unit represented by the following composition formula (2); a film-forming component including a component B consisting of a polymerizable compound having a partial structure represented by the following structural formula (I) (excluding the silsesquioxane); a film-curing component configured to generate radicals when irradiated with ultraviolet light; The coating agent according to claim 1, wherein the component B comprises one or more compounds selected from the group consisting of a polymerizable compound (B1) having at least one cyclic structure selected from the group consisting of an alicyclic structure, an aromatic hydrocarbon ring, and a saturated heterocycle, and having a molecular weight of 300 or less, and a cyclopolymerizable compound (B2) having a structure capable of forming a cyclic structure after polymerization, and having a molecular weight of 300 or less. (R 1 SiO 3 / 2 ) ・・・(1) (R 2 SiO 3 / 2 ) ・・・(2) 【Chemistry 1】 (However, R in the composition formula (1) 1 is an acryloyl group or a methacryloyl group, and R in the composition formula (2) 2 is a monovalent hydrocarbon group, and the symbol "*" in the structural formula (I) indicates a bond to another atom.

2. The coating agent according to claim 1 , wherein the cyclopolymerizable compound (B2) has two of the partial structures in its molecular structure.

3. 3. The coating agent according to claim 2, wherein the cyclopolymerizable compound (B2) has a 1,6-diene structure.

4. The coating agent according to claim 1 , wherein the cyclopolymerizable compound (B2) has an ether bond in its molecular structure.

5. The coating agent according to claim 1, wherein the cyclopolymerizable compound (B2) is a compound represented by the following structural formula (II): 【Chemistry 2】

6. The coating agent according to claim 1 , wherein the component B is the cyclopolymerizable compound (B2).

7. 7. The coating agent according to claim 6, wherein the content of the cyclopolymerizable compound (B2) is 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the component B.

8. The coating agent according to claim 1, wherein the silsesquioxane further comprises a Q structural unit represented by the following composition formula (4): (No) 4 / 2 ) ・・・(4)

9. 2. The coating agent according to claim 1, wherein the content of the component A is 20 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the component B.

10. 2. The coating agent according to claim 1, wherein the film-forming component further comprises a component C consisting of silica particles having a volume-based median diameter of 5 nm or more and 300 nm or less.

11. The coating agent according to claim 10, wherein the surfaces of the silica particles are modified with polyorganosiloxane groups.

12. 11. The coating agent according to claim 10, wherein the content of the component C is 0.5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the component B.

13. The coating agent according to claim 1 , wherein the film-hardening component is configured to be capable of generating both radicals and bases when irradiated with ultraviolet light.

14. a base material made of resin; A resin member comprising: a coating film made of a cured product of the coating agent according to any one of claims 1 to 13, the coating film covering the surface of the substrate.

15. The resin member according to claim 14 , wherein the substrate is made of polycarbonate.

16. 15. The resin member according to claim 14, wherein the coating film has a surface layer exposed on a surface of the resin member and an inner layer interposed between the surface layer and the base material, and an average concentration of Si atoms in the surface layer is higher than an average concentration of Si atoms in the inner layer.

Images