JP2018172472A - Transparent flame-retardant sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent laminate sheet which is transparent, which has a preferable exterior appearance, and has nonflammable property.SOLUTION: There is provided a transparent laminate sheet characterized in that, to each of both surfaces of a sheet formed of a hardening resin and a glass cloth whose optical refraction factors are made match, a sheet having an optical refraction factors in a specific range is laminated. Since the refraction factor on a surface of the laminate sheet, there is less glare of a surrounding landscape, and even when there is a glare, the landscape looks mild, so that the transparent laminate sheet can be preferably used as an interior material for a building or a vehicle. Since the transparent laminate sheet is a composite body with the glass cloth, even when the transparent laminate sheet is exposed to hyperthermia due to fire disaster, the sheet itself does not penetrate due to burning or melting.

Description

  The present invention relates to a transparent flame retardant sheet comprising an epoxy resin composition containing a phosphazene compound and glass fibers. The sheet of the invention is less colored and has excellent heat resistance, transparency, and flame retardancy.

  A curable resin composition containing an epoxy resin is used as a resin having excellent heat resistance in the fields of architecture, civil engineering, automobiles, aircraft, and the like. In the field of semiconductor-related materials, epoxy resins used for electronic devices have been required to have very high characteristics, and in recent years, their use in optoelectronics-related fields has attracted attention.

Display devices such as a liquid crystal display, a plasma display, an EL display, and a portable device are widely used by general consumers, and demands for display on a curved surface and stereoscopic display are increasing as the size, weight, and thickness of the display device are increased. In order to satisfy various requirements such as transparency, hardness, chemical resistance, and gas barrier properties, glass plates are widely used for optical elements such as display elements and front panels of such apparatuses. However, there is a problem that the glass plate is easily broken and heavy, and in order to solve this problem, a plastic material such as an epoxy resin has been studied as an alternative to the glass plate, and various proposals have been made.

  For example, Patent Document 1 describes a transparent resin substrate for a liquid crystal display element using an epoxy resin, an acid anhydride curing agent, and alcohol. Patent Document 2 and Patent Document 3 describe a transparent substrate using a glass cloth and a thermosetting resin, and Patent Document 4 describes a resin sheet using a resin-cured layer containing a glass fiber cloth and inorganic particles. Has been.

  These and other glass substitute plastic materials are required to have high flame retardancy when used for interior members of buildings and transportation machines. In general, a technique of adding a flame retardant is used for the purpose of imparting flame retardancy to plastics, but there is a risk that heat resistance and transparency may be lowered due to phase separation due to plasticity, hydrolyzability, and poor solubility of the flame retardant. (Patent Document 5)

  On the other hand, when a phosphazene-based flame retardant having a reactive group is used as shown in Patent Document 6, a decrease in heat resistance and phase separation can be suppressed, but in order to obtain sufficient flame retardancy It is necessary to increase the amount of addition, often causing a decrease in transparency and coloring.

JP-A-6-337408 JP 2004-233851 A JP 2004-269727 A JP 2005-156840 A Japanese Patent Laying-Open No. 2015-081343 JP 2001-335676 A

  An object of the present invention is to obtain a fiber-reinforced sheet that is less colored and excellent in heat resistance, flame retardancy, and transparency.

  By adding a phosphazene-based flame retardant having an epoxy group introduced into a glass fiber reinforced epoxy resin, the present inventors exhibit flame retardancy with a small amount of addition, less coloration, high heat resistance, transparency, The inventors have found that a sheet having toughness can be obtained, and have reached the present invention.

That is, the present invention
(1) A cyclic and / or chain phosphazene compound (A) having a structure represented by the following formula (1), a compound (B) having two or more epoxy groups in one molecule, and a curing agent (C) A fiber reinforced sheet containing a carboxylic acid or a carboxylic anhydride as a resin composition (D) impregnated into a glass fiber and cured, the refractive index of the resin composition (D) after curing and the refraction of the glass fiber The transparent flame-retardant sheet | seat characterized by the difference with a rate being 0.01 or less.

（式中、ｎは３〜１０を表し、Ｒ_１、Ｒ_２はそれぞれ独立して、少なくとも１つはグリシジルオキシ基置換フェニル基であり、その他はフェニル基、ヒドロキシ基置換フェニル基、または炭素数１〜１１のアルキルエーテル基置換フェニル基を表す。）

(In the formula, n represents 3 to 10, R ₁ and R ₂ are each independently at least one is a glycidyloxy group-substituted phenyl group, and the others are a phenyl group, a hydroxy group-substituted phenyl group, or a carbon number. 1 to 11 alkyl ether group-substituted phenyl group.)

(2) The said transparent flame-retardant sheet | seat in which the said compound (B) contains the polyfunctional epoxy compound shown by following formula (2).

（式中、ｎは０〜１０を表す。）

(In the formula, n represents 0 to 10.)

(3) The transparent flame retardant sheet, wherein the curing agent (C) is a carboxylic acid or carboxylic anhydride having three or more carboxy groups in one molecule.

(4) The said transparent flame-retardant sheet | seat whose epoxy equivalent of the said phosphazene compound (A) is 180-400 g / equiv.

(5) The said transparent flame-retardant sheet | seat whose said phosphazene compound (A) is 1-20 mass% of the said resin composition (D).

(6) A prepreg in which a fiber impregnated with the resin composition (D) is shaped in a semi-cured state.
(7) An interior member including the transparent flame retardant sheet.
(8) A building member or a transport machine using the transparent flame retardant sheet.
(9) Use of the transparent flame retardant sheet in a building member or a transport machine.
About.

  The transparent flame retardant sheet of the present invention has little coloration and is excellent in transparency, flame retardancy, and heat resistance, and is suitable for building members and interior members of transport machinery.

  The phosphazene compound (A) used in the present invention is a cyclic and / or chain phosphazene compound having a structure represented by the following formula (3).

（式中、ｎは３〜１０を表し、Ｒ_１、Ｒ_２はそれぞれ独立して、少なくとも１つはグリシジルオキシ基置換フェニル基であり、その他はフェニル基、ヒドロキシ基置換フェニル基、または炭素数１〜１１のアルキルエーテル基置換フェニル基を表す。）

(In the formula, n represents 3 to 10, R ₁ and R ₂ are each independently at least one is a glycidyloxy group-substituted phenyl group, and the others are a phenyl group, a hydroxy group-substituted phenyl group, or a carbon number. 1 to 11 alkyl ether group-substituted phenyl group.)

  The epoxy equivalent of the phosphazene compound (A) is usually in the range of 180 to 400 g / equiv, preferably 180 to 300 g / equiv.

  The proportion of the phosphazene compound (A) contained in the resin composition (D) is usually 1 to 20% by mass, and preferably 1 to 10% by mass in consideration of reducing coloring.

  The phosphazene compound (A) can be produced according to a known method. For example, it can be produced by reacting a hydroxyphenyl group-substituted phosphazene compound with epihalohydrin in the presence of a basic substance.

  In the reaction of a hydroxyphenyl group-substituted phosphazene compound and an epihalohydrin in the presence of a basic substance, a halide salt formed by supplementing a hydrogen halide is produced as the reaction proceeds. After removing this salt by filtration, the filtrate is concentrated to obtain a crude product of the phosphazene compound (A) in a high yield. This is dissolved in a suitable solvent, washed with water, concentrated and dried under reduced pressure to obtain a highly pure phosphazene compound (A).

  As the hydroxyphenyl group-substituted phosphazene compound, known compounds can be used, such as hydroxyphenoxy-pentaphenoxycyclotriphosphazene, di (hydroxyphenoxy) -tetraphenoxycyclotriphosphazene, tri (hydroxyphenoxy) -triphenoxycyclotriphosphazene, Examples include tetra (hydroxyphenoxy) -diphenoxycyclotriphosphazene, penta (hydroxyphenoxy) -phenoxycyclotriphosphazene, etc., cyclotriphosphazenes and hexahydroxyphenoxycyclotriphosphazenes in which hydroxyphenoxy group and phenoxy group are mixed and substituted It is done. In addition, alkyloxy group-substituted phenoxy groups such as hydroxyphenoxy group, methoxyphenoxy group, ethoxyphenoxy group, propyloxyphenoxy group, isopropyloxyphenoxy group, butyloxyphenoxy group, sec-butyloxyphenoxy group, tert-butyloxyphenoxy group, etc. And cyclotriphosphazene obtained by mixing and substitution. Further, cyclotetraphosphazene, cyclopentaphosphazene, cyclohexaphosphazene, cyclophosphazene mixture (mixture of n in general formula (1) of 3 to 10) in which hydroxyphenoxy group and phenoxy group are mixed and substituted, and not cyclized above Examples thereof include a chain phosphazene mixture. Among these, in the present invention, cyclotriphosphazene in which a hydroxyphenoxy group and a phenoxy group are mixed and substituted is preferable in terms of good compatibility with the resin and heat resistance. Examples of commercially available phosphazene compounds containing this as a main component include SPH-100 manufactured by Otsuka Chemical Co., Ltd.

  The reaction of the hydroxyphenyl group-substituted phosphazene compound and epihalohydrin can be carried out without solvent or in a suitable solvent. When a solvent is used, it is not particularly limited as long as it does not adversely affect the reaction, but tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane-bis (2-methoxyethyl) ether, etc. Examples include ether solvents, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and aprotic polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

  As the epihalohydrin, known ones can be used, and examples thereof include epichlorohydrin, epibromohydrin, epiiodohydrin and the like. The amount used is usually in the range of 1 to 50 mol, preferably 3 to 15 mol, per mol of the hydroxyl group of the hydroxyphosphazene compound.

  In the reaction between the hydroxyphenyl group-substituted phosphazene compound and epihalohydrin, the reaction temperature is usually 20 to 130 ° C, preferably 30 to 100 ° C.

  The basic substance is used to supplement the hydrogen halide generated by the reaction. At this time, the type of basic substance to be used is not particularly limited, but alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable in that they can be obtained at low cost.

  The amount of the basic substance to be used is not particularly limited, but if it is used excessively, it will be mixed into the product or the purification load will increase, so the number of hydroxyl groups in the hydroxyphenyl group-substituted phosphazene compound is 1.0. In general, 1.0 to 2.0 mole times, preferably 1.0 to 1.5 mole times is used.

  The phosphazene compound (A) thus obtained can be further purified. As a purification method in that case, recrystallization, washing, activated carbon treatment, column chromatography and the like can be arbitrarily performed. These purification methods can be repeated or combined.

  The compound (B) having two or more epoxy groups in one molecule used in the present invention (hereinafter referred to as “compound (B)”) means at least two or more in one molecule except for the phosphazene compound (A). Any compound having an epoxy group may be used. A plurality of types of compounds (B) may be used in combination. An aromatic epoxy resin and an aliphatic epoxy resin will be described below as the compound (B) suitably used in the present invention.

  The proportion of the compound (B) contained in the resin composition (D) is usually 20 to 80% by mass, and preferably 30 to 70% by mass in consideration of imparting high heat resistance.

  Aromatic epoxy resins include cresol novolac epoxy resins, phenol novolac epoxy resins, biphenyl-phenol epoxy resins, naphthol epoxy resins and other novolac epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, Bisphenol type epoxy resins such as bisphenol S type epoxy resins, and their polyfunctional modified resins, trisphenolmethane type epoxy resins, glyoxal type epoxy resins, (4 (4 (1,1-bis (p-hydroxyphenyl) -ethyl ) Α, α-dimethylbenzyl) phenol) type epoxy resin and the like. Among these, in the present invention, in view of heat resistance, transparency and color resistance, bisphenol A type epoxy resin, polyfunctional bisphenol A type epoxy resin, (4 (4 (1,1-bis (p-hydroxy Phenyl) -ethyl) α, α-dimethylbenzyl) phenol) type epoxy resins are preferred.

  Examples of the aliphatic epoxy resin include an epoxy resin having an aliphatic cyclic structure and an epoxy resin having no aliphatic cyclic structure. The epoxy resin having an aliphatic side cyclic structure has at least one cyclic aliphatic structure in one molecule. For example, polycondensation of terpene diphenol and phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and aliphatic ring structure dienes (dicyclopentadiene, norbornadiene, hexahydroxyindene, etc.) And glycidyl etherified products derived from these products and modified products thereof, hydrogenated bisphenol (bisphenol A, bisphenol F) type epoxy resins, alicyclic epoxy resins, etc., epoxy resins having a cyclohexyl structure in the molecule, dicyclopentadiene structures And epoxy resin having a triglycidyl isocyanurate structure. Specifically, for example, 1,2-cyclohexanediol diglycidyl ether, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, 1,2-bis (hydroxyalkyl) -1-butanol Examples include epoxy-4- (2-oxiranyl) cyclohexane adducts.

  Examples of the compound (B) having no aliphatic cyclic structure include glycidyl ethers derived from linear or branched alcohols such as hexane diglycidyl ether.

  Among these, in the present invention, in order to adjust the refractive index of the cured product of the resin composition (D), a highly refractive aromatic epoxy resin is preferable as the compound (B), and a bisphenol A type epoxy resin and (4 A mixture of (4 (1,1-bis (p-hydroxyphenyl) -ethyl) α, α-dimethylbenzyl) phenol) type epoxy resin is more preferable. Moreover, in order to adjust the refractive index of the hardened | cured material of the resin composition (D), two or more types chosen from the compound (B) which does not have an aromatic epoxy resin, an aliphatic epoxy resin, and an aliphatic cyclic structure It is also preferable to use the compound (B) in combination.

  The curing agent (C) shown in the present invention is a carboxylic acid or carboxylic anhydride having two or more, preferably three or more, or one or more carboxylic anhydride groups in the molecule. There is no limitation in particular and a well-known general thing can be used.

  The carboxylic acid anhydride group reacts with a hydroxyl group contained in the epoxy resin or a hydroxyl group generated by the carboxylation of the epoxy group first to generate a carboxy group. For this reason, a carboxylic anhydride is counted as a bifunctional carboxy group.

  The proportion of the compound (C) contained in the resin composition (D) is usually 20 to 80% by mass, and preferably 30 to 70% by mass in consideration of imparting high heat resistance.

  Specific examples of the curing agent (C) include, for example, 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, cyclohexane-1,2-dicarboxylic acid anhydride, bicyclo [2] having two carboxy groups. , 2,1] heptane-2,3-dicarboxylic acid anhydride, acid anhydrides such as methylbicyclo [2,2,1] heptane-2,3-dicarboxylic acid anhydride, adipic acid, sebacic acid, cyclohexanedicarboxylic acid Examples thereof include aliphatic carboxylic acids such as acids. In addition, as one having three or more carboxy groups, 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride, 1,2,4,5-cyclohexanetetracarboxylic acid-1,2,4,5 -Acid anhydrides such as dianhydrides, butanetetracarboxylic acid anhydrides, other saturated acid anhydrides such as cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydrides, and fats such as cyclohexanetricarboxylic acid Group carboxylic acids.

  Specific examples of the other curing agent (C) include hydrocarbon diols such as butanediol, hexanediol, nonanediol and cyclohexanediol, hydrocarbon polyhydric alcohols such as glycerin, pentaerythritol and dipentaerythritol, polyethylene glycol , Polyalkylene glycols such as polypropylene glycol and polybutylene glycol, polyester diols such as polycaprolactone diol, inorganic diols such as silicone diol, and other diols and acid anhydrides exemplified in these. Examples include acid anhydrides obtained by reacting carboxylic acids or carboxylic acid halides such as cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride halide.

  Specific examples of the further curing agent (C) include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, and nadic anhydride. And acid anhydride compounds having an unsaturated ring structure.

  Among these, in the present invention, it is preferable to use saturated carboxylic acids having high transparency and acid anhydrides thereof as the curing agent (C) so that the transparency of the cured product of the resin composition (D) is increased. .

  In the present invention, the yellowness of the cured product of the resin composition (D) is preferably less than 2.

  There is no limitation in particular as the kind of glass which comprises the glass fiber used suitably in this invention, A well-known general glass can be used. For example, so-called E-glass, S-glass, T-glass, D-glass, UN-glass, NE-glass, Q-glass and the like can be mentioned.

  Among these, E-glass is most suitable for the use of the present invention because of its availability. Moreover, what processed the glass fiber for controlling adhesiveness with resin and surface tension with a silane coupling agent can be used suitably.

  The optical refractive index of the cured product of the resin composition (D) and the glass fiber is preferably substantially the same in the stage after resin curing, and the difference is 0.01 or less, more preferably 0.005 or less. Preferably there is. This is because the laminated glass sheet obtained can be made transparent by setting the optical refractive index to substantially the same value. When it exceeds this range, the transparency of the laminated glass sheet is lost.

  The glass fiber which consists of E-glass (about 1.55-1.57) which has a close relationship with the kind of glass which comprises glass fiber, and the structure of a resin composition (D), and has the most suitable characteristic is The refractive index is relatively high. For this reason, the refractive index cannot be achieved with the curable resin having only an aliphatic structure in the resin composition (D), and the curable resin having an aliphatic structure and an aromatic structure. Must be used in a balanced manner.

  Therefore, when E-glass is used, the resin composition (D) uses an aromatic epoxy resin as the compound (B) and a saturated carboxylic acid and acid anhydrides as the curing agent (C). It is preferable.

  The resin composition (D) may contain other components in addition to the above components. These other components include antioxidants, light stabilizers, ultraviolet absorbers and the like.

  In the resin composition (D), in order to promote the reaction by heat, a curing catalyst is generally added in order to accelerate the reaction in response to heat or to adjust the curing temperature. Any of these known materials can be used as long as they have the effect of promoting the curing reaction.

  The antioxidant that can be used in the resin composition (D) is not limited as long as it is a known general one such as a phenol-based, sulfur-based, or phosphorus-based antioxidant. However, in view of the characteristics of the present invention, it is preferable to select a material that is colorless and difficult to be colored even when it is used for a long period of time as a circuit board after sealing or heat after curing.

  Examples of the phenolic antioxidant include monophenols, bisphenols, and high-molecular phenols.

  Specific examples of the sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, and the like. .

  Examples of phosphorus antioxidants include phosphites and oxaphosphaphenanthrene oxides.

  These antioxidants can be used alone, but may be used in combination of two or more. The usage-amount of antioxidant is 0.008-1 mass part normally with respect to 100 mass parts of resin compositions of this invention, Preferably it is 0.01-0.5 mass part. In the present invention, a phosphorus-based antioxidant is preferable.

  As the light stabilizer that can be used in the resin composition (D), known general stabilizers can be used, and there is no particular limitation. However, in view of the characteristics of the present invention, it is preferable to select a material that is colorless and is difficult to be colored even when it is used for a long time or for heat during curing. Typical examples of these include hindered amines.

  As the ultraviolet absorber that can be used for the resin composition (D), known general ones can be used, and there is no particular limitation. Examples of ultraviolet absorbers include benzotriazoles and hydroxyphenyltriazines, and can be used in combination with the light stabilizer.

  In the present invention, it is preferable to use an ultraviolet absorber having a low colorability over time. For example, propanoic acid-2- [4- [4,6-bis ([1,1′-biphenyl] -4-yl) -1,3,5-triazin-2-yl] -3-hydroxyphenyl]- Isooctyl ester (for example, Tinuvin 479, manufactured by Ciba Japan Co., Ltd.) and the like can be mentioned.

  When improving the coloring resistance of the present invention, a hydroxyphenyltriazine ultraviolet absorber and a hindered amine light stabilizer are used together.

  The resin composition (D) includes a butyral resin, an acetal resin, an acrylic resin, an epoxy-nylon resin, an NBR-phenol resin, and an epoxy-NBR resin as long as the properties such as transparency and hardness are not impaired. Resin components such as polyamide resin, polyimide resin, and silicone resin can be added as necessary.

  A known general metal salt can be added to the resin composition (D). For example, carboxylic acid metal salts (zinc salts such as 2-ethylhexanoic acid, stearic acid, behenic acid, myristic acid, tin salts, zirconium salts) and phosphate ester metals (zinc salts such as octyl phosphoric acid, stearyl phosphoric acid), Examples thereof include metal compounds such as alkoxy metal salts (such as tributylaluminum and tetrapropylzirconium) and acetylacetone salts (such as acetylacetonezirconium chelate and acetylacetonetitanium chelate). These may be used alone or in combination of two or more. By adding a metal salt, the heat resistance and coloring resistance of the present invention can be improved.

  Examples of the curing catalyst include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl- 2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2′-methylimidazole (1 ′)) ) Ethyl-s-triazine, 2,4-diamino-6 (2′-undecylimidazole (1 ′)) ethyl-s-triazine, 2,4-diamino-6 (2′-ethyl-4-methylimidazole ( 1 ′)) Ethyl-s-triazine, 2,4-diamino-6 (2′-me Ruimidazole (1 ′)) ethyl-s-triazine isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2: 3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxyalkyl Various imidazoles such as imidazole, 2-phenyl-4-hydroxyalkyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxymethylimidazole, and imidazoles and phthalic acid, isophthalic acid, terephthalic acid Acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, maleic acid, salts with polyvalent carboxylic acids such as succinic acid, amides such as dicyandiamide, 1,8-diaza-bicyclo (5,4,0) undecene Diaza compounds such as 7 and their tetra Salts such as phenyl borate and phenol novolak, salts with the above polyvalent carboxylic acids or phosphinic acids, ammonium salts such as tetrabutylammonium bromide, cetyltrimethylammonium bromide, trioctylmethylammonium bromide, triphenylphosphine, tri (toluyl) phosphine Phosphines and phosphonium compounds such as tetraphenylphosphonium bromide, tetraphenylphosphonium tetraphenylborate, hexafluororostibin phosphonium salt, phenols such as 2,4,6-trisaminomethylphenol, tin octylate, cobalt octylate And organometallic compounds such as zinc octylate, zirconium octylate, nickel octylate and cobalt naphthenate. Furthermore, a microcapsule type curing catalyst in which a curing accelerator is used as a microcapsule can be used.

  Which of these curing catalysts is used should be appropriately selected depending on required properties. A curing catalyst is normally used in 0.001-15 mass parts with respect to 100 mass parts of all the resins in a resin composition (D).

  Further, fine particles having a primary particle size of 1 to 200 nm may be added to the resin composition (D). Examples of the fine particles include glass, silica, zirconium oxide, tin oxide, titanium oxide, zirconia, zinc oxide, indium tin oxide, antimony oxide, selenium oxide, yttrium oxide, aluminum oxide, and magnesium fluoride, and contain a dispersion solvent. It can be obtained from the market and used as a colloidal solution dispersed in a fine powder or solvent. Moreover, these can be used 1 type or in mixture of 2 or more types. Dispersion solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and dimethyldimethylacetamide, esters such as ethyl acetate and butyl acetate, nonpolar solvents such as toluene and xylene, etc., each of the thermosetting resin composition of the present invention. What dissolves the components may be selected and used.

  In addition, a silane coupling agent, a release agent, a leveling agent, a surfactant, a dye, a pigment, an inorganic or organic light diffusion filler, and the like can be added.

  In the present invention, addition of a metal salt is preferable for the purpose of improving heat resistance and light resistance. Specifically, carboxylic acid metal salts (zinc salts such as 2-ethylhexanoic acid, stearic acid, behenic acid, myristic acid, tin salts, zirconium salts) and phosphate metal (zinc such as octyl phosphoric acid, stearyl phosphoric acid) Salts), metal compounds such as alkoxy metal salts (such as tributylaluminum and tetrapropylzirconium), and acetylacetone salts (such as acetylacetonezirconium chelate and acetylacetonetitanium chelate). These may be used alone or in combination of two or more.

  A solvent can be used as a 1 type, or 2 or more types of mixed solvent in consideration of the viscosity at the time of using a resin composition (D), a drying rate, etc. Although the usage-amount of a solvent is based on workability | operativity at the time of use and a drying rate, it is 10-200 mass parts normally with respect to 100 mass parts of resin compositions (D), Preferably it is 15-100 mass parts.

  Also when obtaining the resin composition (D) diluted with a solvent, it can be prepared by mixing and dissolving each component according to a conventional method. For example, the varnish of the resin composition (D) can be obtained by charging each component in a round bottom flask equipped with a stirrer and a thermometer and stirring at 40 to 80 ° C. for 0.5 to 6 hours. In this case, a method in which an epoxy resin varnish and a curing agent (C) + a curing catalyst or additive varnish are separately prepared and mixed at the time of use is particularly preferable. As described above, when the fine particles are added, the treatment can be performed by a generally known dispersion method such as a high-speed stirrer such as a homomixer or a sand mill, a microfluidizer, or a three roll.

  In general, the transparent flame-retardant sheet of the present invention is a liquid resin composition (D) as it is, and in the case of a high-viscosity or solid resin composition (D), it is diluted with a solvent or the like to form a solution. It can be obtained by immersing glass fiber, for example, glass cloth, in a so-called resin varnish and evaporating and drying the solvent, and then via a prepreg, or by directly curing without taking out as a prepreg. .

  A prepreg obtained by impregnating a glass fiber sheet with the resin composition (D) in a semi-cured state is also included in the present invention.

  The prepreg of the present invention can be produced by a known general method, and is not particularly limited. For example, a method of impregnating glass fiber with a resin composition (D) dissolved in a solvent and then volatilizing the solvent, a method of impregnating glass fiber with a resin composition (D) that has been thermally melted, and then cooling, A method of applying pressure or the like to a non-cured resin composition (D) molded into a flat shape with a roll or the like, a glass fiber (B) in a mold, and a resin composition (D) heated there For example, using a transfer molding machine or the like.

  After producing the prepreg of the present invention, the cured product obtained by drying and curing is also the transparent flame retardant sheet of the present invention. As described above, the resin composition (D) is suitable for the production of the transparent flame retardant sheet of the present invention because there is no change in the refractive index due to volatilization of the curing agent during curing. The curing temperature and time of the resin composition (D) are 80 to 200 ° C. and 2 to 200 hours. As a curing method, it can be cured at a high temperature at a stretch, but it may be cured at a low temperature of 150 ° C. or lower for a long time. For example, initial curing may be performed at 80 to 150 ° C., and post-curing may be performed at 100 to 200 ° C., and the curing reaction may be promoted by increasing the temperature stepwise.

  In addition, although the drying temperature at the time of obtaining a prepreg using the varnish of a resin composition (D) is based also on the solvent and air volume to be used, 60-200 degreeC is preferable normally. When the glass fiber sheet-like substrate such as glass cloth is impregnated with the varnish and the solvent is dried, the resin composition (D) is brought into a semi-cured state to obtain a prepreg. The drying conditions at this time are not particularly limited, but the temperature is preferably 100 to 180 ° C. and the time is preferably 1 to 30 minutes.

  The prepreg of the present invention is used at least in a state where the curing reaction is not completed, that is, a completely uncured or semi-cured state. At this time, a preferable reaction rate (that is, a value represented by a reaction amount of the prepreg / a reaction amount when the curing reaction is completed) is 0 to 0.95, preferably 0.1 to 0.5. .

The transparent flame-retardant sheet of the present invention can be used as an interior material having both transparency and incombustibility in a building or a transport machine. Specifically, materials such as a smoke-proof wall material, a door member, a wall material, a partition plate, a lighting member, a window, a table, and a chair can be given.
The present invention also includes building members and transport machinery using the transparent flame retardant sheet of the present invention.

  Next, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited at all by the following examples. In the synthesis of the compound, the reaction was terminated when the disappearance of the raw alcohols was confirmed by gel permeation chromatography (hereinafter referred to as “GPC”). In the examples, ECH represents epichlorohydrin, and MEK represents methyl ethyl ketone.

Synthesis Examples 1-3: Glycidyl compound synthesis of phosphazene compound (A) While performing nitrogen purge on a flask equipped with a stirrer, a reflux condenser, and a stirrer, SPH-100 (manufactured by Otsuka Chemical Co., Ltd.) 30 g of hydroxyl group equivalent 240 g / equiv) and ECH described in the table were added, 18 g of 30% aqueous sodium hydroxide solution was added dropwise over 60 minutes, and the mixture was stirred at 90 to 105 ° C. for 3 hours. Subsequently, after the reaction solution was cooled to 20 ° C. and concentrated, the obtained concentrate was dissolved in ethyl acetate, washed with water three times, and dried over anhydrous magnesium sulfate. After anhydrous magnesium sulfate was removed by filtration, the filtrate was concentrated to obtain a product. The epoxy equivalent was measured by measuring the mass of a resin containing 1 equivalent of an epoxy group by the method A shown in JIS K7236: 2009.

Synthesis Example 4: Synthesis of polyfunctional acid anhydride Cyclohexane-1,3,4-tricarboxylic acid-3,4-anhydride halide while purging nitrogen in a flask equipped with a stirrer, a reflux condenser, and a stirring device To 78.6 g, THF was added to make a homogeneous solution. After cooling this solution to 5 ° C. while stirring, 33.6 g of pyridine was added to 28.5 g of pentaerythritol, and a solution made uniform by adding THF was gradually added dropwise while keeping the liquid temperature at 10 ° C. or lower. After completion of the dropwise addition, the mixture was stirred at room temperature for 1 hour, then heated to 50 ° C. and the reaction was continued for 8 hours. Subsequently, the reaction solution was cooled to 20 ° C., and pyridine hydrochloride as an insoluble component was removed by filtration, and then the filtrate was concentrated. The obtained concentrate was dissolved in ethyl acetate, washed 3 times with water, and dried over anhydrous magnesium sulfate. After anhydrous magnesium sulfate was removed by filtration, the filtrate was concentrated to obtain a product.

Examples 1-1 to 10 and Comparative Examples 1-1 to 4: Preparation of a resin composition (D) using a phosphazene compound The phosphazene compounds obtained in Synthesis Examples 1 to 3, SPH- not epoxidized as a comparative example 100 g of 5.6 g, epoxy resin (B) 30 g, carboxylic acid and carboxylic anhydride curing agent (C) 20 g, MEK 24 g as solvent, 0.1 g zinc octoate as other components Was mixed at 70 ° C. to obtain a diluted composition of the resin composition (D) having a solid content of 70% by mass.

Abbreviations in the table
NC-6300: 4 (4 (1,1-bis (p-hydroxyphenyl) -ethyl) α, α-dimethylbenzyl) phenol) type epoxy resin, manufactured by Nippon Kayaku Co., Ltd.
jER828: Liquid bisphenol A epoxy resin, manufactured by Mitsubishi Chemical Corporation
NER-1302: Multifunctional bisphenol A epoxy resin, manufactured by Nippon Kayaku Co., Ltd.
EHPE3150: 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol, manufactured by Daicel Corporation
H-TMAn: 1,2,4-cyclohexanetricarboxylic acid-1,2-anhydride, manufactured by Mitsubishi Gas Chemical Co., Ltd.
MH: 4-methylcyclohexane-1,2-dicarboxylic acid anhydride, manufactured by Shin Nippon Rika Co., Ltd.
TCD-DM / MH: Tricyclodecane dimethanol / 4-methylcyclohexane-1,2-dicarboxylic anhydride equivalent adduct
TMP / MH: Trimethylolpropane / 4-methylcyclohexane-1,2-dicarboxylic anhydride equivalent adduct
IPDA: Isophoronediamine

Examples 2-1 to 10 and Comparative Examples 2-1 to 4: Preparation of cured products (glass cloth-epoxy composite sheet)
MEK was added to the curable resin composition obtained in Example 1 and Comparative Example 1 to adjust the solid content to 50% by mass, and a commercially available glass cloth (E glass cloth: about 30 μm thick, plain weave) was placed and impregnated. I let you. After pulling up the glass cloth, it was dried at 120 ° C. for 7 minutes. The sheet after drying was a solid film. This was further processed for 10 minutes at 150 ° C. while being pressed between PET films that had been subjected to release treatment, and semi-cured to obtain a prepreg. Thereafter, it was cured for 3 hours in a 150 ° C. dryer to obtain a cured product of the present invention. The refractive index after curing of the curable resin (C) was measured at 589 nm by the method A shown in JIS K7142: 2014. Since the refractive index at 589 nm of the glass cloth used in this example is 1.555, Comparative Example 2-1 has a high refractive index and Comparative Example 2-5 has a low refractive index.
Each of the obtained cured products was evaluated for heat resistance, transparency, yellowness, and flame retardancy.

The evaluation method and evaluation criteria for the cured product were as follows.
(1) Transparency Evaluation was made visually.
(2) Yellowness
Evaluation was performed by yellowness YI measured by the method shown in JIS Z 8722.
YI <1.0: ◎
1.0 ≦ YI <1.5 ： ○
1.5 ≦ YI <2.0: △
2.0 ≦ YI ： ×
(3) Flame resistance
Flame retardance was evaluated based on the UL94 VTM test method, and those that reached VTM-0 were marked with ◯, and those that did not reach were marked with ×.

  As is clear from the above results, the transparent flame retardant sheet of the present invention is not colored and is excellent in heat resistance, transparency and flame retardancy. In particular, since the phosphazene compound used in the cured products of Examples 2-1 and 2 contained a large amount of glycidyl groups, the decrease in the crosslinking density was suppressed, and the phosphazene structure was uniformly incorporated into the epoxy resin. It is thought that high heat resistance, flame retardancy, and transparency were obtained. On the other hand, Comparative Examples 2-1 and 2-3 have low transparency because the refractive indexes of the glass cloth and the resin do not match. Moreover, in Comparative Example 2-2, although it has a phenolic hydroxyl group as a reactive group, the transparency considered to be caused by phase separation and a decrease in heat resistance were observed, and flame retardancy could not be imparted. In Comparative Example 2-4, coloring considered to be derived from the amine used as the curing agent was observed.

Claims (9)

A cyclic and / or chain phosphazene compound (A) having a structure represented by the following formula (1), a compound (B) having two or more epoxy groups in one molecule, and a carboxylic acid as a curing agent (C) Or a fiber reinforced sheet containing a carboxylic acid anhydride and cured by impregnating a glass fiber with a resin composition (D), wherein the refractive index of the resin composition (D) after curing and the refractive index of the glass fiber A transparent flame retardant sheet having a difference of 0.01 or less.

(In the formula, n represents 3 to 10, R ₁ and R ₂ are each independently at least one is a glycidyloxy group-substituted phenyl group, and the others are a phenyl group, a hydroxy group-substituted phenyl group, or a carbon number. 1 to 11 alkyl ether group-substituted phenyl group.) The transparent flame-retardant sheet according to claim 1, wherein the compound (B) having two or more epoxy groups in one molecule contains a polyfunctional epoxy compound represented by the following formula (2).

(In the formula, n represents 0 to 10.) The transparent flame-retardant sheet according to claim 1 or 2, wherein the curing agent (C) is a carboxylic acid or carboxylic anhydride having three or more carboxy groups in one molecule. The transparent flame-retardant sheet according to any one of claims 1 to 3, wherein the epoxy equivalent of the phosphazene compound (A) is 180 to 400 g / equiv. The transparent flame-retardant sheet according to any one of claims 1 to 4, wherein the phosphazene compound (A) is 1 to 20% by mass of the resin composition (D). A prepreg obtained by impregnating fibers with the resin composition (D) according to claim 1 and imparting a shape in a semi-cured state. The interior member containing the transparent flame-retardant sheet | seat as described in any one of Claims 1 thru | or 5. A building member or a transport machine using the transparent flame retardant sheet according to any one of claims 1 to 5. Use of the transparent flame retardant sheet according to any one of claims 1 to 5 in a building member or a transport machine.