Curable resin composition

Abstract

To provide a curable resin composition which can be easily applied to a coated body, especially, an electronic material, and imparts flame retardancy to a coated body or can improve flame retardancy of a coated body.SOLUTION: A curable resin composition contains a curable resin, feldspar, nonferrous metal hydroxide, and phosphate, and accordingly can suppress viscosity at a low level, has excellent coating property, can be accurately and easily coated to a desired part of a coated body without impairing a function of the coated body, and provides a cured product of the curable resin composition having excellent flame retardancy.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition. [Background technology]

[0002] BACKGROUND ART In order to suppress the spread of fire in the event of a fire, flame retardancy has been promoted for automobile components, home appliances, electronic materials, sporting goods, building materials, containers for storing flammable liquids, and the like.

[0003] In recent years, the electronics field has made remarkable progress, particularly in the miniaturization, lightening, and increasing density of electronic devices, which has led to an increasing demand for thinner, multi-layered, and higher-definition electronic materials, including printed wiring boards and light-emitting diodes (LEDs).Flame retardancy is also required for these electronic materials.

[0004] Furthermore, containers for storing flammable liquids are also required to have improved flame retardancy in order to improve safety.

[0005] Patent Document 1 discloses a flame-retardant resin composition containing (A) a polymer compound, (B) ammonium polyphosphate, (C) aluminum hydroxide and / or magnesium hydroxide, (D) a polyhydric alcohol, (E) a compound having a melamine skeleton, and (F) hollow ceramic beads and / or expanded graphite. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-14513 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the flame-retardant resin composition of Patent Document 1 has a problem in that the flame retardancy of the film obtained from this flame-retardant resin composition is insufficient.Furthermore, the flame-retardant resin composition of Patent Document 1 has a problem in that it has a high viscosity, making it difficult to apply to electronic materials.

[0008] The present invention provides a curable resin composition that has excellent coatability, can be easily applied to substrates, particularly electronic materials, and can impart flame retardancy to the substrates or improve the flame retardancy of the substrates. [Means for solving the problem]

[0009] The curable resin composition of the present invention contains a curable resin, a feldspar, a non-ferrous metal hydroxide, and a phosphate ester.

[0010] [Curable resin] Curable resins include one-component curable resins and two-component curable resins. One-component curable resins include resins that are cured by introducing a crosslinked structure due to moisture, light irradiation, or heat. Two-component curable resins include resins that are cured by mixing a base resin with a curing agent and introducing a crosslinked structure.

[0011] [1-component curable resin] Examples of the one-component curable resin include a polymer having a hydrolyzable silyl group, a polymer having a hydrolyzable isocyanate group, and a photocrosslinkable polymer, and it is preferable that the one-component curable resin contains a polymer having a hydrolyzable silyl group.

[0012] In the presence of water, the hydrolyzable groups of the hydrolyzable silyl groups in the polymers are hydrolyzed to form silanol groups (≡SiOH). The silanol groups then undergo dehydration condensation to form crosslinked structures. In the presence of water, the hydrolyzable isocyanate groups in the polymers form urea bonds (-NHCONH-) while generating carbon dioxide, forming crosslinked structures.

[0013] The hydrolyzable silyl group is a group formed by bonding 1 to 3 hydrolyzable groups to a silicon atom. The hydrolyzable group of the hydrolyzable silyl group is not particularly limited, and examples thereof include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, an alkenyloxy group, and an oxime group.

[0014] Among these, the hydrolyzable silyl group is preferably an alkoxysilyl group because of its mild hydrolysis reaction. Examples of the alkoxysilyl group include trialkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, and triphenoxysilyl; dialkoxysilyl groups such as propyldimethoxysilyl, methyldimethoxysilyl, and methyldiethoxysilyl; and monoalkoxysilyl groups such as dimethylmethoxysilyl and dimethylethoxysilyl.

[0015] The hydrolyzable isocyanate group refers to an isocyanate group that can form a urea bond (-NHCONH-) by hydrolysis.

[0016] [Polymers containing hydrolyzable silyl groups] The polymer having a hydrolyzable silyl group is not particularly limited, and examples thereof include polyalkylene oxides having a hydrolyzable silyl group, acrylic polymers having a hydrolyzable silyl group, silicone resins having a hydrolyzable silyl group, urethane resins having a hydrolyzable silyl group, and polyolefin resins having a hydrolyzable silyl group. The polymer having a hydrolyzable silyl group preferably contains a polyalkylene oxide having a hydrolyzable silyl group. The polymer having a hydrolyzable silyl group may be used alone or in combination of two or more.

[0017] [Polyalkylene oxide having hydrolyzable silyl groups] In the polyalkylene oxide having a hydrolyzable silyl group, the hydrolyzable silyl group is preferably an alkoxysilyl group, more preferably a dialkoxysilyl group, more preferably a dimethoxysilyl group, and more preferably a propyldimethoxysilyl group.

[0018] The polyalkylene oxide having a hydrolyzable silyl group preferably has 1 to 4 hydrolyzable silyl groups on average per molecule. When the number of hydrolyzable silyl groups in the polyalkylene oxide having a hydrolyzable silyl group is within the above range, the flame retardancy of the cured product of the curable resin composition is improved. The polyalkylene oxide having a hydrolyzable silyl group preferably has a hydrolyzable silyl group at at least one of both ends of its main chain.

[0019] The average number of hydrolyzable silyl groups per molecule in the polyalkylene oxide having hydrolyzable silyl groups is 1 It can be calculated based on the concentration of hydrolyzable silyl groups in the polyalkylene oxide determined by H-NMR and the number average molecular weight of the polyalkylene oxide determined by GPC.

[0020] The polyalkylene oxide constituting the polyalkylene oxide having a hydrolyzable silyl group is a polyalkylene oxide having a main chain represented by the general formula: -(RO) m - (wherein R represents an alkylene group having 1 to 14 carbon atoms, and m represents the number of repeating units and is a positive integer.) The main chain skeleton of the polyalkylene oxide may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units.

[0021] In the present invention, an alkylene group is a divalent atomic group formed by removing two hydrogen atoms bonded to two different carbon atoms in an aliphatic saturated hydrocarbon, and includes both linear and branched atomic groups.

[0022] Examples of the alkylene group include an ethylene group, a propylene group [-CH(CH3)-CH2-], a trimethylene group [-CH2-CH2-CH2-], a butylene group, an amylene group [-(CH2)5-], and a hexylene group.

[0023] Examples of the main chain skeleton of the polyalkylene oxide include polyethylene oxide, polypropylene oxide, polybutylene oxide, polytetramethylene oxide, polyethylene oxide-polypropylene oxide copolymer, and polypropylene oxide-polybutylene oxide copolymer. Among these, polypropylene oxide is preferred. Polypropylene oxide reduces the viscosity of the curable resin composition, improving its coatability and allowing the curable resin composition to be coated accurately in a narrow coating area.

[0024] The number average molecular weight of the polyalkylene oxide having a hydrolyzable silyl group is preferably 3,000 or more, more preferably 10,000 or more. The number average molecular weight of the polyalkylene oxide having a hydrolyzable silyl group is preferably 50,000 or less, more preferably 40,000 or less, and more preferably 30,000 or less. When the number average molecular weight of the polyalkylene oxide is 3,000 or more, the polyalkylene oxide does not easily thermally decompose into low molecular weight compounds, and the cured product of the curable resin composition has excellent flame retardancy. When the number average molecular weight of the polyalkylene oxide is 50,000 or less, the coatability of the curable resin composition is improved, allowing it to be applied accurately to the desired location on the substrate.

[0025] In the present invention, the number average molecular weight of the polyalkylene oxide having a hydrolyzable silyl group means a value calculated in terms of polystyrene measured by GPC (gel permeation chromatography).

[0026] The number average molecular weight of the polyalkylene oxide having a hydrolyzable silyl group can be measured, for example, using the following measuring device and under the following measuring conditions. Measuring device: TOSOH Corporation, product name "HLC-8121GPC / HT" Measurement conditions Column: TSKgelGMHHR-H(20)HT x 3 TSKguardcolumn-HHR(30)HT x 1 Mobile phase: o-DCB 1.0mL / min Sample concentration: 1 mg / mL Detector: Bryce type refractometer Standard material: Polystyrene (TOSOH Corporation, molecular weight: 500-8420000) Elution conditions: 145℃ SEC temperature: 145℃

[0027] Commercially available polyalkylene oxides having a hydrolyzable silyl group can be used. For example, examples of polyalkylene oxides having a hydrolyzable silyl group include those manufactured by Kaneka Corporation under the trade names "MS Polymer S-203," "MS Polymer S-303," "MS Polymer S-303H," "Silyl Polymer SAT-200," "Silyl Polymer SAT-350," and "Silyl Polymer SAT-400." Examples of polyalkylene oxides having a hydrolyzable silyl group include those manufactured by Asahi Glass Company Limited under the trade names "Excestar ESS-3620," "Excestar ESS-2420," "Excestar ESS2410," and "Excestar ESS3430."

[0028] A polyalkylene oxide having a polypropylene oxide main chain and a (methoxymethyl)dimethoxysilyl group at the end of the polypropylene oxide is commercially available from Kaneka Corporation under the trade name "HS-2."

[0029] A polyalkylene oxide having a polypropylene oxide main chain and an isopropyldimethoxymethylsilyl group at the end of the polypropylene oxide is commercially available from Kaneka Corporation under the trade name "SAX720."

[0030] [Acrylic polymer having hydrolyzable silyl groups] As the hydrolyzable silyl group contained in the acrylic polymer having a hydrolyzable silyl group, an alkoxysilyl group is preferred, a trialkoxysilyl group is more preferred, and a trimethoxysilyl group is particularly preferred, because the hydrolysis reaction is mild.

[0031] In an acrylic polymer having a hydrolyzable silyl group, the average number of hydrolyzable silyl groups per molecule is preferably 1 or more, more preferably 2 or more. In an acrylic polymer having a hydrolyzable silyl group, the average number of hydrolyzable silyl groups per molecule is preferably 4 or less, more preferably 2.5 or less. When the number of hydrolyzable silyl groups is 1 or more, the flame retardancy of the cured product of the curable resin composition is improved. When the number of hydrolyzable silyl groups is 4 or less, the viscosity of the curable resin composition is reduced, improving coatability, allowing the curable resin composition to be applied accurately to a narrow application area. Furthermore, when the curable resin composition is applied to the application area, the curable resin composition flows smoothly at the application area, resulting in excellent leveling properties. The acrylic polymer having a hydrolyzable silyl group preferably has a hydrolyzable silyl group at at least one of both ends of its main chain.

[0032] An acrylic polymer having a hydrolyzable silyl group may be used in combination with an acrylic polymer not having a hydrolyzable silyl group. In this case, the total number of hydrolyzable silyl groups per molecule of both polymers is preferably 0.3 or more, more preferably 0.5 or more. When the number of hydrolyzable silyl groups is 0.3 or more, the curability of the curable resin composition is improved. On the other hand, the total number of hydrolyzable silyl groups per molecule of both polymers is preferably 2.0 or less, more preferably 1.8 or less. When the number of hydrolyzable silyl groups is 2.0 or less, the viscosity of the curable resin composition is reduced, improving coatability, allowing the curable resin composition to be applied accurately to a narrow application area. Furthermore, when the curable resin composition is applied to the application area, the curable resin composition flows smoothly at the application area, providing excellent leveling properties.

[0033] The method for introducing a hydrolyzable silyl group into an acrylic polymer is not particularly limited, and examples thereof include a method in which an unsaturated group is introduced into a copolymer of monomers constituting the main chain skeleton, and then a hydrosilane having a hydrolyzable silyl group is allowed to act on the copolymer to hydrosilylate the copolymer.

[0034] The average number of hydrolyzable silyl groups per molecule in the acrylic polymer having hydrolyzable silyl groups is 1 It is calculated based on the concentration of hydrolyzable silyl groups in the acrylic polymer having hydrolyzable silyl groups determined by H-NMR and the number average molecular weight of the acrylic polymer having hydrolyzable silyl groups determined by GPC.

[0035] The main chain skeleton of the acrylic polymer having a hydrolyzable silyl group is preferably a copolymer of a monomer containing methyl (meth)acrylate and butyl (meth)acrylate, more preferably a copolymer of a monomer containing methyl methacrylate and butyl acrylate, and even more preferably a copolymer of a monomer containing methyl methacrylate and n-butyl acrylate. The acrylic polymer having a hydrolyzable silyl group, whose main chain skeleton is the copolymer, improves the flame retardancy of the cured product of the curable resin composition. Note that (meth)acrylate means methacrylate and / or acrylate.

[0036] In the acrylic polymer having a hydrolyzable silyl group, the content of the methyl (meth)acrylate component is preferably 3% by mass or more, more preferably 5% by mass or more. In the acrylic polymer having a hydrolyzable silyl group, the content of the methyl (meth)acrylate component is preferably 70% by mass or less, more preferably 50% by mass or less. When the content of the methyl (meth)acrylate component is 3% by mass or more, the viscosity of the curable resin composition is reduced, improving coatability, allowing the curable resin composition to be applied accurately to a narrow coating area. In addition, when the curable resin composition is applied to the coating area, the curable resin composition flows smoothly at the coating area, providing excellent leveling properties. When the content of the methyl (meth)acrylate component is 70% by mass or less, the viscosity of the curable resin composition is reduced, improving coatability, allowing the curable resin composition to be applied accurately to a narrow coating area.

[0037] In the acrylic polymer having a hydrolyzable silyl group, the content of the butyl (meth)acrylate component is preferably 30 to 97 mass %, more preferably 50 to 95 mass %. When the content of the butyl (meth)acrylate component is 30 mass % or more, the viscosity of the curable resin composition is reduced, improving the coatability, and the curable resin composition can be applied to a narrow coating area with high precision.

[0038] In the acrylic polymer having a hydrolyzable silyl group, the monomers used in the polymer constituting the main chain skeleton may further include other monomers in addition to methyl acrylate, methyl methacrylate, butyl acrylate, and butyl methacrylate.Other monomers include, for example, styrene derivatives such as styrene, indene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, p-chloromethylstyrene, p-methoxystyrene, p-tert-butoxystyrene, and divinylbenzene; compounds having a vinyl ester group such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl benzoate, and vinyl cinnamate; maleic anhydride, N-vinylpyrrolidone, N-vinylmorpholine, methacrylonitrile, acrylonitrile, acrylamide, methacrylamide, N-cyclohexylmaleimide, N-phenylmaleimide, N-laurylmaleimide, N-benzylmaleimide, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, tert-amyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, 2-chloroethyl vinyl ether, ethylene glycol butyl vinyl ether, trimethylsilyl vinyl ether, methyl ... Examples of vinyloxy group-containing compounds include ethylene glycol methyl vinyl ether, (4-vinyloxy)butyl benzoate, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, butane-1,4-diol divinyl ether, hexane-1,6-diol divinyl ether, cyclohexane-1,4-dimethanol divinyl ether, di(4-vinyloxy)butyl isophthalate, di(4-vinyloxy)butyl glutarate, di(4-vinyloxy)butyl succinate, trimethylolpropane trivinyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, 6-hydroxyhexyl vinyl ether, cyclohexane-1,4-dimethanol monovinyl ether, diethylene glycol monovinyl ether, 3-aminopropyl vinyl ether, 2-(N,N-diethylamino)ethyl vinyl ether, urethane vinyl ether, and polyester vinyl ether. These monomers may be used alone or in combination.

[0039] The polymerization method for the acrylic polymer having a hydrolyzable silyl group is not particularly limited, and known methods can be used. Examples of such polymerization methods include free radical polymerization, anionic polymerization, cationic polymerization, UV radical polymerization, living anionic polymerization, living cationic polymerization, and living radical polymerization.

[0040] The weight-average molecular weight of the acrylic polymer having a hydrolyzable silyl group is preferably 1000 to 50000, more preferably 2000 to 30000, and particularly preferably 3000 to 15000. An acrylic polymer having a hydrolyzable silyl group with a weight-average molecular weight within the above range reduces the viscosity of the curable resin composition, improving coatability, allowing the curable resin composition to be coated accurately onto a narrow coating area, and when the curable resin composition is coated onto the coating area, the curable resin composition flows smoothly at the coating area, providing excellent leveling properties.

[0041] [Silicone resin with hydrolyzable silyl groups] Silicone resin refers to a polymer having a main chain formed by repeating siloxane bonds (-Si-O-). A silicone resin having a hydrolyzable silyl group has a plurality of hydrolyzable silyl groups in the main chain of the silicone resin. A silicone resin having a hydrolyzable silyl group preferably has hydrolyzable silyl groups at both ends of the main chain of the silicone resin. The hydrolyzable silyl group contained in the silicone resin having a hydrolyzable silyl group is preferably an oximesilyl group, and more preferably a ketoximesilyl group.

[0042] [Urethane resin with hydrolyzable silyl groups] A urethane resin is a polymer having a main chain formed by repeating urethane bonds (-NHCOO-). A urethane resin having a hydrolyzable silyl group has a plurality of hydrolyzable silyl groups in the main chain of the urethane resin. The urethane resin having a hydrolyzable silyl group preferably has the hydrolyzable silyl group at both ends of the main chain of the urethane resin.

[0043] [Polyolefin resin with hydrolyzable silyl groups] Examples of polyolefin resins include polyethylene resins and polypropylene resins. The polyolefin resin having hydrolyzable silyl groups has a plurality of hydrolyzable silyl groups in the main chain of the polyolefin resin. The polyolefin resin having hydrolyzable silyl groups preferably has hydrolyzable silyl groups at both ends of the main chain of the polyolefin resin.

[0044] [Polymer having hydrolyzable isocyanate groups] Examples of polymers having a hydrolyzable isocyanate group include urethane resins having a hydrolyzable isocyanate group. Urethane resins refer to polymers having a main chain formed by repeating urethane bonds (-NHCOO-). Urethane resins having a hydrolyzable isocyanate group have a plurality of hydrolyzable isocyanate groups in the main chain of the urethane resin. Urethane resins having a hydrolyzable isocyanate group preferably have hydrolyzable isocyanate groups at both ends of the main chain of the urethane resin. Urethane resins include polyether-based urethane resins made from polyether polyol as a raw material and polyester-based urethane resins made from polyester polyol as a raw material, but any of these may be used.

[0045] [Photocrosslinkable polymer] A photocrosslinkable polymer has photocrosslinkable groups in its molecules, and when irradiated with light such as ultraviolet light, chemical bonds are formed between the molecules, forming a crosslinked structure and curing.

[0046] The photocrosslinkable group may be any group capable of forming a chemical bond upon irradiation with light. The photocrosslinkable group is not particularly limited, and examples thereof include a thiol group, a glycidyl group, an oxetanyl group, a vinyl group, a (meth)acryloyl group, a benzophenone group, a benzoin group, and a thioxanthone group. Benzophenone group, benzoin group, and thioxanthone group are preferred, and a benzophenone group is more preferred. Note that (meth)acryloyl refers to methacryloyl or acryloyl.

[0047] The main chain structure of the photocrosslinkable polymer is not particularly limited, and examples thereof include polyolefin resins, acrylic resins, epoxy resins, cyanoacrylate resins, etc. Examples of a method for introducing a photocrosslinkable group into the main chain include a method of polymerizing a monomer composition containing a photocrosslinkable group-containing monomer.

[0048] The photocrosslinkable group-containing monomer is not particularly limited, and examples thereof include glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, 4-(meth)acryloyloxybenzophenone, 4-[2-((meth)acryloyloxy)ethoxy]benzophenone, 4-(meth)acryloyloxy-4'-methoxybenzophenone, 4-(meth)acryloyloxyethoxy-4'-methoxybenzophenone, 4-(meth)acryloyloxy-4'-bromobenzophenone, and 4-(meth)acryloyloxyethoxy-4'-bromobenzophenone, with 4-(meth)acryloyloxybenzophenone and 4-[2-((meth)acryloyloxy)ethoxy]benzophenone being preferred. The ultraviolet crosslinkable group-containing monomer (D) may be used alone or in combination of two or more. Note that (meth)acryloyloxy refers to methacryloyloxy or acryloyloxy.

[0049] [2-component curable resin] The two-component curable resin is not particularly limited, and examples thereof include isocyanate-based polymers and glycidyl-based polymers.

[0050] Isocyanate-based polymers are two-component curable resins consisting of a base resin containing polyisocyanate and a curing agent containing polyol. By mixing the base resin and the curing agent and reacting the polyisocyanate with the polyol, urethane bonds are formed, crosslinking occurs, and the polymer hardens.

[0051] Examples of polyisocyanates include araliphatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. Examples of araliphatic diisocyanates include diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, 1,4-bis(1-isocyanato-1-methylethyl)benzene, ω,ω'-diisocyanato-1,4-diethylbenzene, and urethane prepolymers having isocyanate groups at both ends.

[0052] Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, and trioxyethylene diisocyanate.

[0053] Examples of alicyclic diisocyanates include isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated tetramethylxylene diisocyanate.

[0054] Examples of polyols include polyurethane polyols, polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, and castor oil polyols.

[0055] The glycidyl polymer is a two-component curable resin consisting of a base resin containing an epoxy resin and a curing agent. The epoxy resin is not particularly limited, and examples thereof include bisphenol A epoxy resins obtained by reacting bisphenol A with epichlorohydrin, bisphenol F epoxy resins obtained by reacting bisphenol F with epichlorohydrin, and hydrogenated versions of these, glycidyl ester epoxy resins, novolac epoxy resins, urethane-modified epoxy resins, nitrogen-containing epoxy resins such as triglycidyl isocyanurate, and rubber-modified epoxy resins containing polybutadiene or NBR.

[0056] The curing agent is not particularly limited, and examples thereof include amine-based curing agents, acid anhydride-based curing agents, polyamide-based curing agents, imidazole-based curing agents, and polymercapran-based curing agents.

[0057] Examples of amine-based curing agents include aliphatic polyamines such as polyoxypropylenetriamine, diethylenetriamine, and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0058] Examples of acid anhydride curing agents include tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, HET anhydride, dodecenyl succinic anhydride, etc. Examples of polyamide curing agents include dimer acid, etc.

[0059] [Feldspars] The curable resin composition contains a feldspar. By containing a feldspar in the curable resin composition, a cured product of the curable resin composition has excellent flame retardancy. The feldspar contains feldspar and feldspar spheroid, and feldspar spheroid is preferred. The feldspars may be used alone or in combination of two or more.

[0060] Examples of feldspar include alkali feldspars such as orthoclase, sanidine, microcline, and anorthoclase; and plagioclases such as albite, oligoclase, andesine, albite, anorthite, and anorthite.

[0061] Examples of feldspars include nephelines such as kalsilite and cancrinite, nepheline syenite, leucite, sodalite, hauyne, lazurite, nosean, and melilite, with nepheline syenite being preferred. Note that nepheline syenite is sometimes referred to as syenite.

[0062] The average particle size of the feldspars is preferably 0.1 μm or more, more preferably 1 μm or more, more preferably 2 μm or more, and more preferably 3 μm or more. The average particle size of the feldspars is preferably 50 μm or less, more preferably 25 μm or less, and more preferably 15 μm or less. When the average particle size of the feldspars is 0.1 μm or more, the cohesive force of the curable resin composition before curing is improved, and the curable resin composition can be accurately coated on a narrow coating area. When the average particle size of the feldspars is 50 μm or less, the feldspars can be uniformly dispersed in the curable resin composition, imparting excellent mechanical strength to the cured product of the curable resin composition and imparting excellent flame retardancy to the coated object stably over a long period of time. The average particle size of the feldspars refers to a value measured by image analysis using a transmission electron microscope. Specifically, 100x magnification photographs of feldspars are taken using a transmission electron microscope, 50 randomly selected feldspars are measured for their diameters, and the arithmetic mean of the diameters of each feldspar is taken as the average particle size of the feldspars. The diameter of a feldspar refers to the diameter of the smallest circle that can surround the feldspar.

[0063] The content of the feldspar in the curable resin composition is preferably 1 part by mass or more, more preferably 30 parts by mass or more, more preferably 50 parts by mass or more, and more preferably 80 parts by mass or more, per 100 parts by mass of the curable resin. The content of the feldspar in the curable resin composition is preferably 800 parts by mass or less, more preferably 600 parts by mass or less, more preferably 450 parts by mass or less, more preferably 300 parts by mass or less, more preferably 200 parts by mass or less, more preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the feldspar is within the above range, the cured product of the curable resin composition has excellent flame retardancy, and the viscosity of the curable resin composition is reduced to improve coatability, allowing the curable resin composition to be coated accurately in a narrow coating area.

[0064] [Non-ferrous metal hydroxides] The curable resin composition contains a non-ferrous metal hydroxide. By containing the non-ferrous metal hydroxide in the curable resin composition, a cured product of the curable resin composition has excellent flame retardancy. The non-ferrous metal hydroxides may be used alone or in combination of two or more.

[0065] The non-ferrous metal hydroxide is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, dawsonite, calcium aluminate, dihydrated gypsum, calcium hydroxide, zinc hydroxide, nickel hydroxide, copper (II) hydroxide, and chromium (III) hydroxide. Aluminum hydroxide and magnesium hydroxide are preferred because the endothermic effect exerted by the non-ferrous metal hydroxide during thermal decomposition improves the flame retardancy of the cured product of the curable resin composition.

[0066] The average particle size of the non-ferrous metal hydroxide is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 0.8 μm or more. The average particle size of the non-ferrous metal hydroxide is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 2 μm or less. The average particle size of the non-ferrous metal hydroxide refers to the particle size D50 at which the cumulative frequency of particles from the smaller particle size side in the volume-based particle size distribution measured by laser diffraction is 50 mass%.

[0067] The content of the non-ferrous metal hydroxide in the curable resin composition is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and more preferably 30 parts by mass or more, per 100 parts by mass of the curable resin. The content of the non-ferrous metal hydroxide in the curable resin composition is preferably 250 parts by mass or less, more preferably 200 parts by mass or less, and more preferably 150 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the non-ferrous metal hydroxide is within the above range, the cured product of the curable resin composition has excellent flame retardancy, and the viscosity of the curable resin composition is reduced to improve coatability, allowing the curable resin composition to be coated accurately in a narrow coating area.

[0068] [Phosphate ester] The curable resin composition contains a phosphate ester. Due to the inclusion of the phosphate ester in the curable resin composition, a cured product of the curable resin composition has excellent flame retardancy. The phosphate ester may be used alone or in combination of two or more.

[0069] The phosphate ester is not particularly limited, and examples thereof include monophosphate ester and condensed phosphate ester.

[0070] Monophosphate esters are phosphate esters having one phosphorus atom in the molecule. Examples of monophosphate esters include, but are not limited to, trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, and tri(2-ethylhexyl)phosphate; halogen-containing phosphate esters such as tris(β-chloropropyl)phosphate; trialkoxy phosphates such as tributoxyethyl phosphate; aromatic ring-containing phosphate esters such as tricresyl phosphate, trixylenyl phosphate, tris(isopropylphenyl)phosphate, cresyl diphenyl phosphate, and diphenyl(2-ethylhexyl)phosphate; and acidic phosphate esters such as monoisodecyl phosphate and diisodecyl phosphate. Preferred monophosphate esters are aromatic ring-containing phosphate esters, with tricresyl phosphate being preferred.

[0071] The condensed phosphate ester is a phosphate ester having multiple phosphorus atoms in the molecule. The condensed phosphate ester is not particularly limited, and examples thereof include aromatic condensed phosphate esters such as trialkyl polyphosphate, resorcinol polyphenyl phosphate, bisphenol A polycresyl phosphate, and bisphenol A polyphenyl phosphate.

[0072] Phosphate esters have excellent compatibility with curable resins, reduce the viscosity of the curable resin composition to improve its coatability, and enable the curable resin composition to be applied accurately to narrow application locations. Therefore, trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, resorcinol polyphenyl phosphate, bisphenol A polycresyl phosphate, and bisphenol A bisdiphenyl phosphate [formula (V)] are preferred, and trigresyl phosphate, resorcinol polyphenyl phosphate [formula (II)], cresyl di-2,6-xylenyl phosphate [formula (III)], tris(chloropropyl) phosphate [formula (IV)], bisphenol A polycresyl phosphate, and bisphenol A bisdiphenyl phosphate [formula (V)] are more preferred.

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] The phosphate ester is preferably in a liquid state at 20° C. and 1 atmosphere (0.101 MPa). The term "liquid" refers to a state in which the phosphate ester does not have a fixed shape, is fluid, and has a substantially fixed volume.

[0078] When the phosphate ester is liquid, the viscosity of the phosphate ester is preferably 1 mPa·s or more, more preferably 50 mPa·s or more, and even more preferably 500 mPa·s or more. The viscosity of the phosphate ester is preferably 30,000 mPa·s or less, more preferably 10,000 mPa·s or less, and even more preferably 5,000 mPa·s or less. The viscosity of the phosphate ester is a value measured using a Brookfield type B viscometer specified in JIS K7117.

[0079] The content of the phosphate ester in the curable resin composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, more preferably 5 parts by mass or more, more preferably 15 parts by mass or more, more preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and more preferably 40 parts by mass or more, per 100 parts by mass of the curable resin. The content of the phosphate ester in the curable resin composition is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, more preferably 150 parts by mass or less, more preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the phosphate ester is 1 part by mass or more, the cured product of the curable resin composition has excellent flame retardancy, and the viscosity of the curable resin composition is reduced, improving coatability, allowing the curable resin composition to be applied accurately to narrow coating areas. When the content of the phosphate ester is 300 parts by mass or less, the curability of the curable resin composition is improved.

[0080] In the curable resin composition, the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate ester [(total content of feldspars and non-ferrous metal hydroxides) / (content of phosphate ester)] is preferably 2.0 or more, and more preferably 2.5 or more. In the curable resin composition, the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate ester [(total content of feldspars and non-ferrous metal hydroxides) / (content of phosphate ester)] is preferably 20 or less, more preferably 15 or less, more preferably 12 or less, more preferably 10 or less, more preferably 8 or less, more preferably 6 or less, more preferably 4 or less, and more preferably 3.5 or less. When the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate ester [(total content of feldspars and non-ferrous metal hydroxides) / (content of phosphate ester)] is 2.0 or more, the film strength of the cured product of the curable resin composition is improved. When the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate esters in the curable resin composition [(total content of feldspars and non-ferrous metal hydroxides) / (content of phosphate ester)] is 20 or less, the film strength of the cured product of the curable resin composition is improved.

[0081] [Glass frit] The curable resin composition preferably contains glass frit. The glass frit acts as a binder to bind the combustion residue of the curable resin and feldspars in the combustion residue of the cured product of the curable resin composition, and the combustion residue has excellent strength. Therefore, the combustion residue of the curable resin composition is stably present at the coated portion of the substrate, and can impart excellent flame retardancy to the substrate.

[0082] Examples of glasses constituting the glass frit include phosphate glass, borate glass, bismuth oxide glass, silicate glass, and sodium oxide glass, with phosphate glass and borate glass being preferred, and phosphate glass being more preferred. These glass frits can be obtained by adjusting B2O3, P2O5, ZnO, SiO2, Bi2O3, Al2O3, BaO, CaO, MgO, MnO2, ZrO2, TiO2, CeO2, SrO, VO5, SnO2, Li2O, Na2O, KO, CuO, Fe2O3, and the like in predetermined component ratios.

[0083] The content of glass frit in the curable resin composition is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and more preferably 40 parts by mass or more, per 100 parts by mass of curable resin. The content of glass frit in the curable resin composition is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of curable resin. When the content of glass frit is 5 parts by mass or more, the combustion residue of the cured product of the curable resin composition has excellent strength and is stably present in the coated area of ​​the substrate, thereby imparting excellent flame retardancy to the substrate. When the content of glass frit is 200 parts by mass or less, the viscosity of the curable resin composition is reduced, improving coatability, and the curable resin composition can be coated accurately into narrow coating areas.

[0084] [Silanol condensation catalyst] The curable resin composition may contain a silanol condensation catalyst, which is a catalyst for promoting a dehydration condensation reaction between silanol groups formed by hydrolysis of the hydrolyzable silyl groups contained in the curable resin when the curable resin has hydrolyzable silyl groups.

[0085] Examples of silanol condensation catalysts include dibutyltin diacetylacetonate, 1,1,3,3-tetrabutyl-1,3-dilauryloxycarbonyl-distannoxane, dibutyltin dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin phthalate, bis(dibutyltin laurate) oxide, dibutyltin bis(acetylacetonate), dibutyltin bis(monoester maleate), tin octoate, dibutyltin octoate, dioctyltin oxide, dibutyltin bis(triethoxysilicate), bis(dibutyltin bistriethoxysilicate) oxide, and dibutyltin oxybisethoxysilicate and other organic tin compounds; tetra-n-butoxy titanate, and tetraisopropoxy titanate and other organic titanium compounds, and organic tin compounds are preferred.These silanol condensation catalysts may be used alone or in combination of two or more.

[0086] The silanol condensation catalyst is preferably 1,1,3,3-tetrabutyl-1,3-dilauryloxycarbonyl-distannoxane, which makes it possible to easily adjust the curing rate of the curable resin composition.

[0087] The content of the silanol condensation catalyst in the curable resin composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and more preferably 0.3 parts by mass or more, per 100 parts by mass of the curable resin. The content of the silanol condensation catalyst in the curable resin composition is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, more preferably 6 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the silanol condensation catalyst in the curable resin composition is 0.1 parts by mass or more, the curing rate of the curable resin composition can be increased, and the time required for curing the curable resin composition can be shortened. When the content of the silanol condensation catalyst in the curable resin composition is 10 parts by mass or less, the curable resin composition has an appropriate curing rate, and the storage stability and handleability of the curable resin composition can be improved.

[0088] [Dehydrating agent] The curable resin composition preferably further contains a dehydrating agent, which can prevent the curable resin composition from being cured by moisture contained in the air or the like during storage.

[0089] Examples of dehydrating agents include silane compounds such as vinyltrimethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, phenyltrimethoxysilane, and diphenyldimethoxysilane; and ester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and ethyl orthoacetate. These dehydrating agents may be used alone or in combination. Among them, vinyltrimethoxysilane is preferred.

[0090] The content of the dehydrating agent in the curable resin composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, per 100 parts by mass of the curable resin. The content of the dehydrating agent in the curable resin composition is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the dehydrating agent in the curable resin composition is 0.5 parts by mass or more, the effects obtained by the dehydrating agent are sufficiently obtained. Furthermore, when the content of the dehydrating agent in the curable resin composition is 20 parts by mass or less, the curable resin composition has excellent curability.

[0091] [Other additives] The curable resin composition may contain other additives such as a thixotropic agent, an antioxidant, an ultraviolet absorber, a pigment, a dye, an anti-settling agent, an aminosilane coupling agent, a thixotropic agent, a plasticizer, and a solvent, within the range that does not impair the physical properties of the curable resin composition. Among these, the thixotropic agent, the ultraviolet absorber, and the antioxidant are preferred.

[0092] The curable resin composition preferably contains an aminosilane coupling agent. By using the aminosilane coupling agent, the rubber elasticity and adhesiveness of the cured product of the curable resin composition can be improved. The aminosilane coupling agent means a compound containing a silicon atom to which an alkoxy group is bonded and a functional group containing a nitrogen atom in one molecule.

[0093] Specific examples of aminosilane coupling agents include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N,N'-bis-[3-(trimethoxysilyl)propyl]ethylenediamine, N,N'-bis-[3-(triethoxysilyl)propyl]ethylenediamine, N,N'-bis-[3-(methyldimethoxysilyl)propyl]ethylenediamine, N,N'-bis-[3-(trimethoxysilyl)propyl]hexamethylenediamine, and N,N'-bis-[3-(triethoxysilyl)propyl]hexamethylenediamine. These aminosilane coupling agents may be used alone or in combination of two or more.

[0094] Among these, preferred examples of the aminosilane coupling agent include 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and more preferred example is N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0095] The content of the aminosilane coupling agent in the curable resin composition is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the curable resin. When the content of the aminosilane coupling agent is within the above range, the rubber elasticity and adhesiveness of the cured product of the curable resin composition can be improved.

[0096] The thixotropy-imparting agent may be any agent capable of imparting thixotropy to the curable resin composition. Preferred examples of the thixotropy-imparting agent include hydrogenated castor oil, fatty acid bisamide, and fumed silica.

[0097] The content of the thixotropy-imparting agent in the curable resin composition is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, per 100 parts by mass of the curable resin. The content of the thixotropy-imparting agent in the curable resin composition is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, per 100 parts by mass of the curable resin. When the content of the thixotropy-imparting agent in the curable resin composition is 0.1 parts by mass or more, thixotropy can be effectively imparted to the curable resin composition. Furthermore, when the content of the thixotropy-imparting agent in the curable resin composition is 200 parts by mass or less, the curable resin composition has an appropriate viscosity, and the handleability of the curable resin composition is improved.

[0098] Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers, with benzotriazole-based ultraviolet absorbers being preferred. The content of the ultraviolet absorber in the curable resin composition is preferably 0.1 parts by mass or more relative to 100 parts by mass of the curable resin. The content of the ultraviolet absorber in the curable resin composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, relative to 100 parts by mass of the curable resin.

[0099] Examples of antioxidants include hindered phenol antioxidants, monophenol antioxidants, bisphenol antioxidants, and polyphenol antioxidants, with hindered phenol antioxidants being preferred. The content of the antioxidant in the curable resin composition is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, per 100 parts by mass of the curable resin. The content of the antioxidant in the curable resin composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of the curable resin.

[0100] [Light stabilizer] The curable resin composition preferably contains a hindered amine light stabilizer, which can provide a curable resin composition that can maintain excellent rubber elasticity for a longer period of time after curing.

[0101] Examples of hindered amine light stabilizers include a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dibutylamine·1,3,5-triazine·N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine) and N-(2,2,6,6 poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], and a polycondensate of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol.

[0102] Preferred examples of the hindered amine light stabilizer include NOR-type hindered amine light stabilizers, which can provide a curable resin composition that is inhibited from decreasing in rubber elasticity over time after curing.

[0103] The NOR hindered amine light stabilizer has a NOR structure in which an alkyl group (R) is bonded to a nitrogen atom (N) contained in a piperidine ring skeleton via an oxygen atom (O). The number of carbon atoms in the alkyl group in the NOR structure is preferably 1 to 20, more preferably 1 to 18, and particularly preferably 18. Examples of the alkyl group include a linear alkyl group, a branched alkyl group, and a cyclic alkyl group (a saturated alicyclic hydrocarbon group).

[0104] Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl groups. Examples of branched alkyl groups include isopropyl, isobutyl, sec-butyl, and tert-butyl. Examples of cyclic alkyl groups (saturated alicyclic hydrocarbon groups) include cyclopentyl, cyclohexyl, and cyclooctyl groups. In addition, the hydrogen atoms constituting the alkyl group may be substituted with halogen atoms (e.g., fluorine, chlorine, and bromine atoms) or hydroxyl groups.

[0105] Examples of the NOR type hindered amine light stabilizer include hindered amine light stabilizers represented by the following formula (I).

[0106] [ka]

[0107] When a NOR-type hindered amine light stabilizer is used, it is preferable to use the NOR-type hindered amine light stabilizer in combination with a benzotriazole-based ultraviolet absorber or a triazine-based ultraviolet absorber, thereby providing a curable resin composition in which the decrease in rubber elasticity over time after curing is more significantly suppressed.

[0108] The content of the hindered amine light stabilizer in the curable resin composition is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the curable resin. The content of the hindered amine light stabilizer in the curable resin composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, relative to 100 parts by mass of the curable resin.

[0109] [Curable resin composition] The curable resin composition can be produced by mixing a curable resin, feldspar, a non-ferrous metal hydroxide, and a phosphate ester with additives added as needed. The curable resin composition may be in the form of a suspension or emulsion by being suspended or emulsified in an aqueous solvent. The curable resin composition may also be in the form of a solution by being dissolved in a solvent. Examples of aqueous solvents include water, alcohols such as ethyl alcohol, methyl alcohol, and isopropyl alcohol. Examples of solvents include xylene, toluene, and acetone.

[0110] The curable resin composition contains a feldspar, a non-ferrous metal hydroxide, and a phosphate ester, and the cured product of the curable resin composition has excellent flame retardancy. Furthermore, the curable resin composition has a low viscosity, which allows it to be applied to desired locations on a substrate with high precision. In particular, the curable resin composition can be applied to specified narrow locations on electronic materials, which are becoming increasingly miniaturized, with high precision.

[0111] Therefore, the curable resin composition can be applied to a predetermined location on a substrate with high precision without affecting the performance of the substrate, particularly electronic materials. The curable resin composition can impart or improve excellent flame retardancy to a substrate, particularly electronic materials and / or electronic devices containing electronic materials.

[0112] Furthermore, by setting the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate ester (total content of feldspars and non-ferrous metal hydroxides / content of phosphate ester) in a predetermined range, the cured product of the curable resin composition has excellent film strength (impact resistance). The curable resin composition is applied to a substrate that requires impact resistance, and a cured product of the curable resin composition with excellent impact resistance can be formed on the surface of the substrate. Even when an impact force is applied to the substrate, the cured product of the curable resin composition does not suffer damage such as cracks, and the excellent flame retardancy imparted to the substrate can be stably maintained.

[0113] The object to be coated is not particularly limited, and examples thereof include electronic devices, electronic materials, and storage containers (synthetic resin containers, metal containers, etc.).

[0114] Examples of electronic devices include, but are not limited to, car navigation systems, mobile phones, smartphones, game consoles, digital cameras, televisions, DVD players, electronic dictionaries, calculators, hard disk recorders, personal computers, video cameras, printers, liquid crystal displays, plasma displays, radios, and electronic musical instruments.

[0115] As electronic devices are becoming smaller and lighter, the electronic materials that make up the devices are also becoming smaller. Examples of such electronic materials include, but are not limited to, printed wiring boards, light-emitting diodes (LEDs), light-emitting diode-mounted boards, flexible copper-clad laminates, bonding sheets, touch panels, and sensor substrates.

[0116] The storage container is not particularly limited, but examples thereof include containers for storing flammable liquids (for example, organic solvents, organic compounds, gasoline, diesel, kerosene, etc.).

[0117] The method for applying the curable resin composition to a predetermined coating location on the substrate is not particularly limited, and examples thereof include a coating method using a brush and a coating method using a known coating tool.

[0118] The viscosity of the curable resin composition is preferably 500 mPa·s or more, more preferably 1000 mPa·s or more, and even more preferably 3000 mPa·s or more. The viscosity of the curable resin composition is preferably 200,000 mPa·s or less, more preferably 100,000 mPa·s or less, and even more preferably 50,000 mPa·s or less. The viscosity of the curable resin composition is a value measured using a BH-type viscometer under conditions of 23°C, 10 rpm, and rotor No. 5.

[0119] The curable resin composition applied to the substrate is cured to produce a cured product. The curing of the curable resin may be carried out in a known manner depending on the type of curable resin (for example, by supplying moisture, irradiating with light such as ultraviolet light, or by heating).

[0120] The cured product of the curable resin composition generates a strong combustion residue when burned by the heat of a fire, and this combustion residue remains stably disposed at the coated area even in the event of a fire, thereby exhibiting excellent flame retardancy. [Effects of the Invention]

[0121] The curable resin composition of the present invention has excellent coatability due to its low viscosity, and can be applied accurately and easily to desired locations on a substrate, particularly an electronic material, without impairing the function of the substrate.

[0122] Furthermore, the cured product produced by curing the curable resin composition has excellent flame retardancy, and can impart or improve excellent flame retardancy to the coated object, particularly electronic materials and / or electronic devices made of electronic materials. DETAILED DESCRIPTION OF THE INVENTION

[0123] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. [Example]

[0124] The following raw materials were used in producing the curable resin compositions of the Examples and Comparative Examples.

[0125] [Curable resin] Polyalkylene oxide with hydrolyzable silyl groups (polyalkylene oxide with a main chain skeleton consisting of polypropylene oxide and a dimethoxysilyl group at the end of the main chain, number average molecular weight: 38,000, manufactured by Kaneka Corporation, product name "Excestar S303H")

[0126] [Feldspars] Feldspar (Nepheline syenite, average particle size: 5 μm, manufactured by Shiraishi Calcium Co., Ltd., product name "Nespar")

[0127] [Non-ferrous metal hydroxides] Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., product name "BF013", average particle size: 1 μm) Magnesium hydroxide (manufactured by Konoshima Chemical Co., Ltd., product name "Magseeds S", average particle size: 1 μm)

[0128] [Phosphate ester] Tricresyl phosphate (monophosphate ester, manufactured by Daihachi Chemical Co., Ltd. under the trade name "TCP," viscosity: 58 mPa·s) Cresyl di-2,6-xylenyl phosphate (monophosphate ester, manufactured by Daihachi Chemical Co., Ltd. under the trade name "PX-110", viscosity: 1200 mPa s) Tris(chloropropyl)phosphate (monophosphate ester, manufactured by Daihachi Chemical Industry Co., Ltd., trade name "TMCPP", viscosity: 69 mPa·s) Resorcinol polyphenyl phosphate (condensed phosphate ester, Daihachi Chemical Industry Co., Ltd., product name "CR-733S", viscosity: 800 mPa·s) Bisphenol A bisdiphenyl phosphate (condensed phosphate ester, manufactured by Daihachi Chemical Industry Co., Ltd., trade name "CR-741", viscosity: 2300 mPa s)

[0129] [Glass frit] Glass frit (phosphate-based glass, "VY0144" manufactured by Nippon Frit Co., Ltd., main components: P2O5, AI2O3, and R2O, where R is an alkali metal atom, softening point: 404°C)

[0130] [Other additives] Polypropylene glycol (plasticizer, manufactured by AGC under the trade name "Exenol 3020") Silanol condensation catalyst (dibutyltin diacetylacetonate, manufactured by Nitto Kasei Co., Ltd., product name "U220H") Dehydrating agent (vinyltrimethoxysilane, product name "KBM1003" manufactured by Shin-Etsu Chemical Co., Ltd.) Aminosilane coupling agent (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM-603)

[0131] (Examples 1 to 11, Comparative Examples 1 to 3) The curable resin, feldspar, non-ferrous metal hydroxide, phosphate ester, glass frit, polypropylene glycol, silanol condensation catalyst, dehydrating agent, and aminosilane coupling agent were mixed in the amounts shown in Table 1 using a planetary mixer under vacuum for 60 minutes until uniform, thereby obtaining a curable resin composition.

[0132] The resulting curable resin compositions were measured for flame retardancy, post-combustion hardness, coatability, and viscosity in the following manner. The results are shown in Table 1.

[0133] The film strength of the obtained curable resin composition was measured in the following manner, and the results are shown in Table 1.

[0134] (Flame retardant) A test sheet with a thickness of 1.5 mm was prepared using the curable resin composition and aged for 7 days at 23° C. The test sheet was cut into a flat rectangular shape measuring 15 mm long x 130 mm wide x 1.5 mm thick to prepare five test pieces.

[0135] The test was conducted based on the UL94V-0 standard. Specifically, one horizontal end of the test specimen was held with a clamp and the test specimen was hung vertically. Next, a flame was applied to the other horizontal end (bottom end) of the vertically hung test specimen using a burner for 3 seconds, and after the burner was temporarily removed from the test specimen, the other horizontal end of the test specimen was again applied with a burner for 3 seconds to measure flame retardancy. Evaluation was based on the following criteria. A: For each test specimen, the afterflame time after two exposures was within 10 seconds, and the total afterflame time for the five test specimens was within 50 seconds. Furthermore, no test specimens remained red-hot (glowing) for more than 30 seconds after the second exposure. B: For each test specimen, the afterflame time after two exposures was within 10 seconds, and the total afterflame time for five test specimens exceeded 50 seconds. Furthermore, no test specimens remained red-hot (glowing) for more than 30 seconds after the second exposure. C: For each test specimen, the afterflame time after two exposures was within 10 seconds, and the total afterflame time for five specimens exceeded 50 seconds. Furthermore, some specimens continued to glow for more than 30 seconds after the second exposure. D: When all test pieces burned down to the clamp, it did not fall under any of A to C.

[0136] (Hardness after combustion) The curable resin composition was cured for one week in an atmosphere of 23°C and 50% relative humidity to produce a cured product. 100 g of the cured product of the curable composition was prepared as a test piece. The test piece was placed in a combustion furnace. The test piece was burned in the combustion furnace at 600°C for 30 minutes. Immediately after the end of combustion, the combustion residue obtained by burning the test piece was left in an atmosphere of 23°C for one hour. Next, the rubber elasticity of the combustion residue was measured using a type A durometer at a measurement temperature of 23°C in accordance with JIS K6253. Evaluation was based on the following criteria. A: The rubber hardness was 30 or higher. B: The rubber hardness was 20 or more and less than 30. C: The rubber hardness was 10 or more and less than 20. D: The rubber hardness was less than 10 or too brittle to be measured with a type A durometer.

[0137] (Coatability) The curable resin composition was filled into a volumetric syringe and attached to an air-operated dispenser (Performus X100, manufactured by Nordson Corporation), and the coating properties were measured. Substrates were prepared on which coating grooves with widths of 0.5 mm, 1.0 mm, and 2.0 mm were formed. The coating grooves with widths of 0.5 mm, 1.0 mm, and 2.0 mm were referred to as "Coating Grooves 1 to 3," respectively.

[0138] The curable resin composition was applied to each of the coating grooves having widths of 0.5 mm, 1.0 mm, and 2.0 mm by operating an air dispenser at 23°C and an air pressure of 0.6 MPa. Evaluation was performed based on the following criteria. A: All coating grooves 1 to 3 were coated cleanly. B: Coating grooves 2 and 3 were coated cleanly, but coating groove 1 was not coated cleanly. C: Coating groove 3 was coated cleanly, but coating grooves 1 and 2 were not coated cleanly. D: None of coating grooves 1 to 3 could be coated cleanly.

[0139] (viscosity) The viscosity of the curable resin composition was measured using a BH type viscometer under conditions of 23°C, 10 rpm, and rotor No. 5.

[0140] (film strength) The curable resin composition was applied to a thickness of 3 mm on the release-treated surface of the release-treated substrate, and then the curable composition was aged for 1 month in an environment of 23°C and a relative humidity of 50%. The cured product of the curable resin composition was peeled off from the substrate.

[0141] The cured product of the curable composition was cut into a No. 3 dumbbell shape according to JIS K6251 to prepare a test piece. A tensile test was carried out using the obtained test piece at a tensile speed of 200 mm / min. In the tensile test, the strength at the time when the test piece broke was measured, and this strength was taken as the coating strength.

[0142] [Table 1]

Claims

1. A curable resin composition comprising a curable resin, a feldspar, a non-ferrous metal hydroxide, and a phosphate ester.

2. 2. The curable resin composition according to claim 1, wherein the curable resin composition contains a polyalkylene oxide having a hydrolyzable silyl group.

3. 3. The curable resin composition according to claim 1, wherein the non-ferrous metal hydroxide contains aluminum hydroxide.

4. 3. The curable resin composition according to claim 1, wherein the mass ratio of the total content of feldspars and non-ferrous metal hydroxides to the content of phosphate ester (total content of feldspars and non-ferrous metal hydroxides / content of phosphate ester) is 2.0 or more.

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