JP7188529B2 - resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition, and more particularly to a resin composition capable of forming a cured product having high translucency and a cured product obtained from the resin composition.

Translucent resin materials are often used as part of materials constituting a light-emitting device having a light-emitting element such as an LED for the purpose of protecting the light-emitting element from the external environment (Patent Document 1). Examples of such translucent resin materials include various resins such as thermosetting resins such as silicone resins and epoxy resins, and thermoplastic resins such as polycarbonate resins and acrylic resins. On the other hand, light-emitting devices using LEDs and the like are used in various applications such as automobiles, ships, trains, aircraft, electronic boards, traffic signal lights, and various types of lighting. is required to maintain its translucency even under environmental load such as heat.

JP 2017-157723 A

Accordingly, an object of the present invention is to provide a curable resin composition capable of forming a cured product having high translucency and excellent maintenance of translucency against environmental loads such as heat, and a cured product thereof. .

In addition, a resin composition that can easily obtain a cured film in the form of a film having particularly high translucency and excellent maintenance of the translucency against environmental loads such as heat, and a cured film in the form of the resin composition are provided. to provide.

The present inventors have found that a cured product of a resin composition containing a bisphenol AF type epoxy resin, a phenoxy resin and a phosphonium salt has high translucency (particularly high transparency), and furthermore, when placed in a high temperature environment, The inventors have found that the decrease in translucency is extremely small, and have completed the present invention by conducting further research based on this finding.

That is, the present invention includes the following contents.
[1] A resin composition containing the following components (A) to (C).
(A) bisphenol AF type epoxy resin (B) thermoplastic resin containing phenoxy resin (C) curing accelerator containing phosphonium salt [2] The resin composition according to [1] above, wherein the phosphonium salt is an ionic liquid.
[3] The resin composition according to [1] or [2] above, wherein the phosphonium cation of the phosphonium salt is a tetraalkylphosphonium cation.
[4] The resin composition according to any one of [1] to [3] above, further comprising (D) an epoxy resin (excluding component (A)).
[5] The resin composition according to any one of [1] to [4] above, which is in the form of a film.
[6] A cured product of the resin composition according to any one of [1] to [5] above.
[7] The cured body according to [6] above, wherein the b* value in the L*a*b* color system is less than 1.0 both before and after storage at 110° C. for 100 hours. .
[8] The cured film having a thickness of 120 μm has a parallel light transmittance of 80% or more for both D65 light before and after storage at 110° C. for 100 hours, above [6]. Or the cured product according to [7].

According to the present invention, it is possible to obtain a curable resin composition that has high translucency and can form a cured product that is excellent in maintaining translucency against environmental loads such as heat. In particular, since the resin composition of the present invention is easy to form into a film, the use of the resin composition of the present invention has high translucency and excellent maintenance of translucency against environmental loads such as heat. A film-like cured product can be easily obtained.

In addition, "highly translucent" as used in the present invention means that a particularly high parallel light transmittance is obtained (that is, high transparency). Also, for example, in the JIS (Japanese Industrial Standards) [Packaging Terms] standard and the Japan Standard Industrial Classification (Ministry of Internal Affairs and Communications) [Plastic Film, Sheet, Flooring, Synthetic Leather Manufacturing Industry] definition, the thickness is 200 μm (250 μm). Based on this, those with a thickness of less than 200 μm (250 μm) are classified as “films”, and those with a thickness of 200 μm (250 μm) or more are classified as “sheets”. , Not only those with a thickness of less than 200 μm (250 μm), which is classified as the above “film”, but also those with a thickness of 200 μm (250 μm) or more, which is classified as the above “sheet” It means a "thin molding" including those having

The present invention will now be described in accordance with its preferred embodiments.
[Resin composition]
The resin composition of the present invention contains, as essential components, (A) a bisphenol AF type epoxy resin, (B) a thermoplastic resin containing a phenoxy resin, and (C) a curing accelerator containing a phosphonium salt.

<(A) Bisphenol AF type epoxy resin>
The bisphenol AF type epoxy resin (hereinafter also referred to as component (A)) used in the present invention is not particularly limited, and for example, an epoxy resin represented by the following formula (I) can be used.

(Wherein, R1 to R8 each independently represent a hydrogen atom, a fluorine atom, or an alkyl group, and n represents an integer of 0 or 1 or more.)

In formula (I), R1 to R8 may be different or the same.
When R1 to R8 are alkyl groups, alkyl groups having 1 to 4 carbon atoms are preferred.

Among epoxy resins represented by formula (I), 4,4′-[2,2,2-trifluoro-1-(trifluoromethyl ) ethylidene]bisphenol type epoxy resins are particularly preferred.

(A) A commercially available bisphenol AF type epoxy resin can be used. Commercially available bisphenol AF type epoxy resins include, for example, "YX7760" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 245 g/eq), "YX7763" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 420 g/eq), and the like.

In the resin composition of this invention, (A) component can use 1 type(s) or 2 or more types. In addition, the content of the component (A) in the resin composition is not particularly limited, but from the viewpoint of maintaining the translucency of the cured product, 10% by mass with respect to 100% by mass of the non-volatile content in the resin composition % or more is preferable, 15 mass % or more is more preferable, and 20 mass % or more is still more preferable. Further, from the viewpoint of handling properties when the resin composition is made into a film, it is preferably 95% by mass or less, more preferably 90% by mass or less, and 63% by mass or less with respect to 100% by mass of the nonvolatile content in the resin composition. Even more preferred.

As will be described later, the resin composition of the present invention may contain epoxy resins other than component (A), but does not contain component (A) and contains epoxy resins other than component (A). In the case of a resin composition, even if a highly transparent cured body can be obtained, it is not possible to obtain a cured body that is excellent in maintaining the translucency when placed in a high-temperature environment.

<(B) Thermoplastic resin containing phenoxy resin>
One of the characteristics of the resin composition of the present invention is that it contains a thermoplastic resin together with the component (A), and the thermoplastic resin contains a phenoxy resin. That is, the thermoplastic resin (hereinafter also referred to as component (B)) is mainly phenoxy resin, preferably 90 to 100% by mass of the total phenoxy resin, more preferably 95 to 100% by mass of the total Phenoxy resin.

Since the main component of the thermoplastic resin is a phenoxy resin, the resin composition of the present invention can be easily formed into a film, has high translucency, and maintains its high translucency even when placed in a high-temperature environment. A film-like cured product can be easily obtained. If the ratio of the phenoxy resin to the total thermoplastic resin is less than 90% by mass, it may not be possible to obtain a cured product with high translucency.

Suitable phenoxy resins include one or two selected from bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, cyclohexane skeleton and norbornene skeleton. Examples include those having more than one skeleton. Phenoxy resins having a biphenyl skeleton and/or a cyclohexane skeleton are particularly preferred. One or more phenoxy resins can be used.

Examples of commercially available phenoxy resins include YX7200B35 (manufactured by Mitsubishi Chemical Co., Ltd.: biphenyl skeleton and cyclohexane skeleton-containing phenoxy resin, nonvolatile content: 35% by mass, epoxy equivalent: 9,000 g/eq), 1256 (manufactured by Mitsubishi Chemical Corporation: bisphenol A skeleton-containing phenoxy resin, epoxy equivalent: 7,800 g/eq), YX6954BH35 (manufactured by Mitsubishi Chemical Corporation: bisphenolacetophenone skeleton-containing phenoxy resin, non-volatile content: 35% by mass, epoxy equivalent: 13,000 g/eq).

Examples of thermoplastic resins other than phenoxy resins in component (B) include polyvinyl acetal resins, polyimide resins, polyamideimide resins, polyethersulfone resins, polysulfone resins, polyester resins, (meth)acrylic polymers, and the like. can. These can use 1 type(s) or 2 or more types.

Handleability (e.g., coatability of resin composition varnish (prevention of repelling)) when forming a resin composition into a film (that is, when obtaining a film-like resin composition), imparting flexibility to a cured product, etc. From the above point, the weight average molecular weight of component (B) is preferably 10,000 or more, more preferably 20,000 or more. However, if the weight-average molecular weight is too large, the compatibility with component (A) is reduced, and it tends to be difficult to obtain a cured product having high translucency. Therefore, the weight average molecular weight is preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 50,000 or less.

The weight average molecular weight in the present invention is measured by a gel permeation chromatography (GPC) method (converted to polystyrene). The weight average molecular weight by the GPC method is measured using LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device, Shodex K-800P/K-804L/K-804L manufactured by Showa Denko Co., Ltd. as a column, and chloroform or the like as a mobile phase. can be measured at a column temperature of 40° C. and calculated using a standard polystyrene calibration curve.

In the resin composition of the present invention, the content of the component (B) in the resin composition is not particularly limited, but it is From the viewpoint of workability (prevention of repelling), imparting flexibility to the cured product, etc., it is preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 10% by mass or more, based on 100% by mass of the nonvolatile matter in the resin composition % or more by mass is more preferable. On the other hand, when the amount of component (B) is too large, the melt viscosity of the resin composition increases and the adhesiveness of the film-like resin composition tends to decrease. Therefore, the content of component (B) is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less with respect to 100% by mass of non-volatile matter in the resin composition. .

<(C) Curing Accelerator Containing Phosphonium Salt>
One of the characteristics of the resin composition of the present invention is that it contains a curing accelerator together with the components (A) and (B), and the curing accelerator contains a phosphonium salt. That is, by using at least a phosphonium salt as a curing accelerator (hereinafter also referred to as component (C)), it becomes easier to obtain a cured product with high translucency. Therefore, the component (C) is mainly composed of a phosphonium salt, preferably 90 to 100% by weight of the total curing accelerator is a phosphonium salt, more preferably 95 to 100% by weight of the total curing accelerator is a phosphonium salt. and particularly preferably the entire curing accelerator is a phosphonium salt.

Since the main component of the curing accelerator is a phosphonium salt, it is easy to obtain a cured product with high translucency (especially transparency). In particular, there is a possibility that a cured product with high transparency cannot be obtained.

Phosphonium salts include, for example, cations of the formula (II):

[Wherein, R11, R12, R13, and R14 are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms, and part of the hydrocarbon group is substituted with a hetero atom or a hydroxy group; good too. ]

is a phosphonium cation represented by
AlCl ₄ ⁻ ; Al ₂ Cl ₇ ⁻ ; BF ₄ ⁻ ; PF ₆ ^{− ;} ClO ₄ ^{− ;} NO ₃ ^{− ;} fluoride ion, chloride ion, bromide ion , Halide anions such as iodide ion; Alkyl sulfate anions such as methanesulfonate ion; Trifluoromethanesulfonate ion, hexafluorophosphonate ion, trifluorotris(pentafluoroethyl)phosphonate ion, bis(trifluoromethane Fluorinated compound anions such as sulfonyl)imide ions, trifluoroacetate ions, and tetrafluoroborate ions; phenolic anions such as phenol ions, 2-methoxyphenol ions, and 2,6-di-tert-butylphenol ions; , acidic amino acid ions such as glutamate ions; neutral amino acid ions such as glycine ions, alanine ions, phenylalanine ions; formula (III):

(Wherein, R is a straight or branched hydrocarbon group having 1 to 5 carbon atoms, or a substituted or unsubstituted phenyl group, and X represents a side chain of an amino acid.)

N-acyl amino acid ions represented by; Salts that are anions selected from the group consisting of carboxylate anions such as ions, benzoate ions, and the like can be mentioned.

Specific examples of the phosphonium cation represented by formula (II) include, for example, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium Tetraalkylphosphonium cations such as cations; Tetraarylphosphonium cations such as tetraphenylphosphonium cations; Allyltrialkylphosphonium cations such as allyltributylphosphonium cations; Tetrakis(hydroxyalkyl)phosphonium cations such as tetrakis(hydroxymethyl)phosphonium cations; be done.

Further, specific examples of the N-acylamino acid ion represented by formula (III), which is an anion, include N-benzoylalanine ion, N-acetylphenylalanine ion, aspartate ion, glycine ion, N-acetylglycine ion, and the like. to be

Specific examples of phosphonium salts include tetraethylphosphonium bromide, n-butyltriphenylphosphonium bromide, tetrabutylphosphonium bromide, triethylbenzylphosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium iodide, tributylmethyl Phosphonium iodide, tributyloctylphosphonium bromide, tributylhexadecylphosphonium bromide, allyltributylphosphonium bromide, benzyltributylphosphonium chloride, tetraphenylphosphonium bromide, tetrabutylphosphonium-o,o-diethylphosphorodithioate, trioctylethylphosphonium bromide, Tetrakis(hydroxymethyl)phosphonium sulfate, ethyltriphenylphosphonium bromide, tetrabutylphosphonium decanate, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, tetraphenylphosphonium thiocyanate, tetra Phenylphosphonium dicyanamide, n-butyltriphenylphosphonium dicyanamide, tetrabutylphosphonium-2-pyrrolidone-5-carboxylate, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium α - lipoate, tetrabutylphosphonium formate, tetrabutylphosphonium lactate, bis(tetrabutylphosphonium) tartrate salt, tetrabutylphosphonium hippurate salt, tetrabutylphosphonium N-methylhippurate salt, benzoyl-DL-alanine tetrabutylphosphonium salt, N-acetylphenylalanine tetrabutylphosphonium salt, 2,6-di-tert-butylphenol tetrabutylphosphonium salt, L-aspartic acid monotetrabutylphosphonium salt, glycine tetrabutylphosphonium salt, N-acetylglycine tetrabutylphosphonium salt and the like. be done.

In addition, from the viewpoint of preventing coloring of the cured product (higher transparency of the cured product), the phosphonium salt is an ionic liquid capable of curing the epoxy resin at a temperature of 140 ° C. or less (preferably 120 ° C. or less), that is, 140 C. or lower (preferably 120.degree. C. or lower) is preferred. Moreover, the phosphonium salt is preferably a phosphonium salt in which the phosphonium cation is a tetraalkylphosphonium cation. That is, the phosphonium salt is particularly preferably an ionic liquid of a phosphonium salt in which the phosphonium cation is a tetraalkylphosphonium cation.

Examples of ionic liquids of phosphonium salts in which the phosphonium cation is a tetraalkylphosphonium cation include tetrabutylphosphonium decanate, N-acetylglycine tetrabutylphosphonium salt, tetrabutylphosphonium-2-pyrrolidone-5-carboxylate, tetrabutylphosphonium acetate, Tetrabutylphosphonium decanoate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium α-lipoate, tetrabutylphosphonium formate, tetrabutylphosphonium lactate, bis(tetrabutylphosphonium) tartrate, tetrabutylphosphonium hippurate, N- Methylhippuric acid tetrabutylphosphonium salt, benzoyl-DL-alanine tetrabutylphosphonium salt, N-acetylphenylalanine tetrabutylphosphonium salt, 2,6-di-tert-butylphenoltetrabutylphosphonium salt, L-aspartic acid monotetrabutylphosphonium salt , glycine tetrabutylphosphonium salt, and the like.

In the present invention, one or more phosphonium salts can be used.

As the curing accelerator (that is, component (C)) in the present invention, a curing accelerator other than the phosphonium salt may be used together with the phosphonium salt as long as the effects of the present invention are not impaired. Examples of curing accelerators other than phosphonium salts include ionic liquids other than ionic liquids of phosphonium salts. , guanidinium ions and pyridinium ions, and/or ionic liquids in which the cations are sulfonium cations such as triethylsulfonium ions.

Examples of anions in these ionic liquids containing ammonium cations and ionic liquids containing sulfonium cations include the same anions as those exemplified in the ionic liquids of phosphonium salts described above.

Examples of curing accelerators other than phosphonium salts include imidazole compounds, tertiary amine compounds, amine adduct compounds, organic acid dihydrazide compounds, and the like.

In the resin composition of the present invention, the amount of component (C) is preferably 0.1 to 3% by mass, more preferably 0.2 to 2% by mass, based on 100% by mass of the nonvolatile content of the resin composition. 0.4 to 1.5 mass % is more preferred. If this amount is less than 0.1% by mass, sufficient curability may not be obtained, and if this amount is more than 3% by mass, the storage stability of the resin composition may be impaired.

<(D) epoxy resin (excluding component (A))>
In the resin composition of the present invention, an epoxy resin other than component (A) (hereinafter also referred to as component (D)) is added from the viewpoint of improving the adhesiveness of the resin composition and the mechanical strength of the cured product of the resin composition. can be contained.

Examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, biphenyl alkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resins, aromatic glycidylamine type epoxy resins (e.g., tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyltoluidine, diglycidylaniline, etc.), alicyclic epoxy resins, aliphatic linear epoxy resins, Phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, epoxy resin having a butadiene structure, diglycidyl etherate of bisphenol, diglycidyl etherate of naphthalenediol, glycidyl etherate of phenols, and alcohol and diglycidyl etherified products, alkyl-substituted products, halides and hydrogenated products of these epoxy resins. Among them, those having high translucency themselves are preferable, and suitable epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, diglycidyl etherate of bisphenol, and the like.
(D) Component can use 1 type(s) or 2 or more types.

The epoxy resin may be liquid or solid, and both liquid and solid epoxy resins may be used. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature (25°C).

In the resin composition of the present invention, the amount of component (D) is preferably 5% by mass or more with respect to 100% by mass of nonvolatile matter from the viewpoint of adhesiveness of the resin composition and mechanical strength of the cured product of the resin composition. , more preferably 10% by mass or more, and even more preferably 20% by mass or more. In addition, from the viewpoint of maintaining the translucency of the cured product, it is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less relative to 100% by mass of the non-volatile matter in the resin composition. .

In the present invention, "epoxy resin" means a thermosetting resin having two or more epoxy groups in one molecule and an epoxy equivalent of 7,000 or less. It means a thermoplastic resin having an epoxy equivalent of more than 7,000. A phenoxy resin may have an epoxy group like an epoxy resin, but in the present invention, they are distinguished by their epoxy equivalent weight. The epoxy equivalent of the epoxy resin is preferably 50 to 5,000 from the viewpoint of reactivity and the like.
, more preferably 50 to 3,000, still more preferably 80 to 2,000, still more preferably 100 to 1,000, still more preferably 120 to 1,000, and particularly preferably 140 to 500. The "epoxy equivalent" is the number of grams (g/eq) of a resin containing one gram equivalent of epoxy groups, and is measured according to the method specified in JIS K7236.

Further, in the present invention, the molecular weight of the epoxy resin (referring to the weight average molecular weight in the case of polymers) is preferably 100 to 5,000, more preferably 250 to 3,000.

The content of the epoxy resin in the resin composition of the present invention (the content of component (A) when component (i) does not contain component (D), and the content of component (A) when component (ii) contains component (D) The total content of component (D) is preferably 30% by mass or more, more preferably 40% by mass or more, relative to 100% by mass of non-volatile matter in the resin composition. Moreover, it is preferably 95% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, and particularly preferably 66% by mass or less, based on 100% by mass of the non-volatile matter of the resin composition. If the amount is less than 30% by mass, the adhesiveness of the resin composition and the mechanical strength of the cured product tend to decrease.

The resin composition of the present invention is prepared by mixing the above-described components with an organic solvent, if necessary, using a kneading roller, a rotating mixer, or the like.

<Application>
INDUSTRIAL APPLICABILITY The resin composition of the present invention is used as a translucent member for protecting a light-emitting element in a light-emitting device having a light-emitting element such as an LED or an EL element from the external environment. The form of the resin composition is not particularly limited, and may be liquid (varnish), solid (for example, film), or semi-solid, depending on the shape and size of the translucent member in the light-emitting device. selected. A film-like resin composition is preferable because a film-like cured body obtained by curing the composition can be used as a highly translucent panel member as it is, and a large-area transparent panel can be easily obtained. In general, the term "panel" is used for products with relatively high hardness (rigidity), and the terms "film" and "sheet" tend to be used for products with relatively low hardness (rigidity). "Panel member" and "panel" in "transparent panel" here also mean products with relatively high hardness (rigidity).

A film-like resin composition (hereinafter also referred to as a "resin composition film") is, for example, a varnish ( resin composition varnish) is applied onto a release-treated support, and the organic solvent is removed from the varnish applied onto the support by heating (hot air blowing, etc.) and/or vacuum treatment using a known device. By doing so, a film-like resin composition is formed.

Examples of the release-treated support include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; Plastic films (preferably PET films) such as polyester; polycarbonate; and polyimide, and metal foils such as aluminum foil, stainless steel foil and copper foil are used. Examples of the release treatment of the release-treated support include release treatment using a release agent such as a silicone resin release agent, an alkyd resin release agent, or a fluororesin release agent.

The solid content of the resin composition varnish is preferably 20-80% by mass, more preferably 30-70% by mass.

Although there are no particular restrictions on the heating conditions for removing the organic solvent from the resin composition varnish, heating at about 50 to 150° C. for about 3 to 10 minutes is usually preferred.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolves such as cellosolve; Examples include carbitols such as butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Any one of these organic solvents may be used alone, or two or more thereof may be used in combination.

The thickness of the film-like resin composition varies depending on the type of object to be protected and the application site, but generally ranges from 1 to 300 μm, preferably from 5 to 200 μm.

The film-shaped resin composition formed on the support is preferably protected with a protective film for protection until the resin composition is cured. A release-treated protective film can be laminated on the resin composition of (1) using a known device. Equipment used for laminating the protective film includes, for example, a roll laminator, a press machine, a vacuum pressure laminator, and the like.

Release-treated protective films include, for example, polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; cycloolefin polymers, polyethylene terephthalate (hereinafter sometimes abbreviated as "PET"), polyesters such as polyethylene naphthalate; polycarbonate; A support made of a plastic film such as polyimide (preferably a PET film) or a metal foil such as an aluminum foil, a stainless steel foil, or a copper foil and subjected to mold release treatment is used. The release treatment includes, for example, a release treatment using a release agent such as a silicone resin release agent, an alkyd resin release agent, or a fluororesin release agent.

<Hardened body>
The cured product of the present invention is obtained by thermally curing the resin composition of the present invention, and serves as a translucent member. When the film-shaped resin composition is cured, a film-shaped cured body is obtained, which becomes a film-shaped translucent member.

The curing temperature for thermosetting is preferably 100° C. or higher, more preferably 120° C. or higher, from the viewpoint of sufficiently advancing the curing reaction. In addition, from the viewpoint of preventing coloring of the cured product, the temperature is preferably 180° C. or lower, more preferably 165° C. or lower. Moreover, the heating time is preferably 10 minutes or longer, more preferably 20 minutes or longer. Moreover, 120 minutes or less is preferable, and 90 minutes or less is more preferable.

Heating means include, for example, a hot air circulation oven, an infrared heater, a heat gun, a high-frequency induction heating device, and heating by pressing a heat tool.

A transparent member having a desired shape can also be formed by pouring a resin composition varnish prepared from the resin composition of the present invention into a mold and heating to remove the organic solvent and perform a curing reaction.

The cured product of the present invention has high translucency and is excellent in maintaining translucency against heat load. For example, a cured film having a thickness of 120 μm exhibits a parallel light transmittance of 80% or more (preferably 84% or more) at 400 nm before and after storage at 110° C. for 100 hours. .

The parallel light transmittance at 400 nm of the cured film having a thickness of 120 μm was measured by forming a laminate in which the cured film was sandwiched between PET films, as described in Examples below. and air as a reference.

In addition, the cured product of the present invention exhibits a b* value of less than 1.0 in the L*a*b* color system both before and after storage when stored at 110 ° C. for 100 hours, and has a yellow tint. is extremely small, and a highly transparent cured product that does not turn yellow even under heat load is obtained. The b* value is preferably 0.98 or less, more preferably 0.95 or less.
Therefore, according to the cured product of the present invention, a translucent member having excellent heat resistance can be realized. In particular, the rate of change in the b* value after storage relative to the b* value before storage when stored at 110 ° C. for 100 hours (b* value after storage / b* value before storage) is less than 2.5 (preferably is 2.3 or less, more preferably 2.1 or less) and 0.5 or more (preferably 0.55 or more, more preferably 0.6 or more). For example, when the cured product of the present invention is used as a light-transmitting member constituting a light-emitting device, even if the light-transmitting member is heated due to the heat generated by the light-emitting operation of the light-emitting element, the light-transmitting member has high transparency. Since the light property is stably maintained, it is possible to realize a light-emitting device in which the amount of light emitted from the light-emitting element to the outside is highly stable over time.

It should be noted that the "b* value of the L*a*b* color system" referred to here is a film-shaped resin composition having a thickness of 120 µm, a cured body obtained by heat curing at 100 ° C. for 60 minutes and 150 ° C. for 30 minutes. It is a measured value for (sample) and is measured by the method described in the later-described initial transparency evaluation test and heat resistance evaluation test.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

Materials used in Examples and Comparative Examples are as follows.
<Epoxy resin>
"YX7760" (manufactured by Mitsubishi Chemical Corporation): bisphenol AF type epoxy resin, epoxy equivalent 245 g / eq
"YX7763" (manufactured by Mitsubishi Chemical Corporation): bisphenol AF type epoxy resin, epoxy equivalent 420 g / eq
"828EL" (manufactured by Mitsubishi Chemical Corporation): bisphenol A type epoxy resin, epoxy equivalent 185 g / eq
"N-695" (manufactured by DIC): cresol novolac type epoxy resin, epoxy equivalent 215 g/eq "YL7924" (manufactured by Mitsubishi Chemical Corporation): diglycidyl etherate of bisphenol, epoxy equivalent 390 g/eq
"EHPE3150" (manufactured by Daicel): alicyclic epoxy resin, epoxy equivalent 180 g / eq
"ZX-1059" (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.): a mixture of bisphenol A type epoxy resin (50% by mass) and bisphenol F type epoxy resin (50% by mass), epoxy equivalent 165 g / eq

<Thermoplastic resin>
"YX7200B35" (manufactured by Mitsubishi Chemical Corporation): phenoxy resin containing biphenyl skeleton and cyclohexane skeleton, non-volatile matter 35% by mass, weight average molecular weight 30,000, epoxy equivalent: 9,000 g/eq
"1256B40" (manufactured by Mitsubishi Chemical Corporation): bisphenol A skeleton-containing phenoxy resin, non-volatile matter 40% by mass, weight average molecular weight 45,000, epoxy equivalent: 7,800 g / eq "BX-5" (manufactured by Sekisui Chemical Co., Ltd.) : Polyvinyl acetal resin, weight average molecular weight 130
,000
"SG-P3" (manufactured by Nagase ChemteX Corporation): epoxy group-containing acrylic acid ester copolymer resin, non-volatile content 15% by mass, weight average molecular weight 850,000

<Curing accelerator>
"TBP-DA" (manufactured by Hokko Chemical Industry Co., Ltd.): Phosphonium salt 1 (tetrabutylphosphonium decanoate)
Phosphonium salt 2: N-acetylglycine tetrabutylphosphonium salt "EMI24" (manufactured by Mitsubishi Chemical Corporation): imidazole curing accelerator

Each composition of Examples and Comparative Examples was prepared according to the procedure shown below. In addition, in the following description, "part" of the amount used for each material means "mass part" unless otherwise specified. In addition, the amount used for materials containing solvents is the total amount including the solvent, and Table 1 below shows the amount of non-volatile matter only.

<Example 1: Preparation of resin composition 1>
8 parts of "YX7760" (bisphenol AF type epoxy resin), 30 parts of "YX7200B35" (phenoxy resin), and 8.35 parts of "YL7924" (diglycidyl etherate of bisphenol) were mixed with 5 parts of methyl ethyl ketone and 5 parts of cyclohexanone. It was heated and dissolved. 0.18 part of "TBP-DA" (phosphonium salt) was mixed therewith to prepare a resin composition 1.

<Example 2: Preparation of resin composition 2>
In Example 1, the amount of "YX7760" (bisphenol AF type epoxy resin) was 8
parts to 6.6 parts, the amount of "YX7200B35" (phenoxy resin) was changed from 30 parts to 34 parts, and "ZX-1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) was added to 2 parts. was added. A resin composition 2 was prepared in the same manner as in Example 1 except for the above matters.

<Example 3: Preparation of resin composition 3>
In Example 2, the amount of "YX7760" (bisphenol AF type epoxy resin) was changed from 6.6 parts to 10.3 parts, and the amount of "YX7200B35" (phenoxy resin) was changed from 34 parts to 23.4 parts. . A resin composition 3 was prepared in the same manner as in Example 2 except for the above matters.

<Example 4: Preparation of resin composition 4>
In Example 1, 2 parts of "ZX-1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) were added, and the amount of "TBP-DA" (phosphonium salt) was changed from 0.18 parts to 0.135 parts. A resin composition 4 was prepared in the same manner as in Example 1 except for the above items.

<Example 5: Preparation of resin composition 5>
In Example 4, the amount of "TBP-DA" (phosphonium salt) was changed from 0.135 parts to 0.36 parts. Resin composition 5 was prepared in the same manner as in Example 4 except for the above matters.

<Example 6: Preparation of resin composition 6>
In Example 1, "YX7760" (bisphenol AF type epoxy resin) was changed to "YX7763" (bisphenol AF type epoxy resin), and "ZX-1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin). Added 2 parts. A resin composition 6 was prepared in the same manner as in Example 1 except for the above matters.

<Example 7: Preparation of resin composition 7>
In Example 1, 30 parts of "YX7200B35" (phenoxy resin) was changed to 26.25 parts of "1256B40" (bisphenol A type phenoxy resin), and "ZX-1059" (bisphenol A type epoxy resin and bisphenol F type epoxy resin mixture) was added. Also, the amount of “TBP-DA” (phosphonium salt) was changed from 0.18 parts to 0.36 parts. Resin composition 7 was prepared in the same manner as in Example 1 except for the above matters.

<Example 8: Preparation of resin composition 8>
In Example 1, 2 parts of "ZX-1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) were added, and 0.18 parts of "TBP-DA" (phosphonium salt) was added to N-acetylglycine tetra Butylphosphonium salt (manufactured by the method described in JP-A-2016-186843) was changed to 0.18 parts. Resin composition 7 was prepared in the same manner as in Example 1 except for the above matters.

<Example 9: Preparation of resin composition 9>
In Example 1, the amount of "YX7760" (bisphenol AF type epoxy resin) was changed from 8 parts to 16.35 parts, and 8.35 parts of "YL7924" was changed to 0 parts. A resin composition 9 was prepared in the same manner as in Example 1 except for the above matters.

<Example 10: Preparation of resin composition 10>
In Example 1, 8.35 parts of "YL7924" (diglycidyl etherate of bisphenol, manufactured by Mitsubishi Chemical Corporation) was changed to 10.35 parts of "EHPE3150" (alicyclic epoxy resin), and "TBP-DA" (phosphonium salt) was changed from 0.18 parts to 0.36 parts. A resin composition 10 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 1: Preparation of Resin Composition 11>
In Example 1, "YX7760" (bisphenol AF type epoxy resin) was changed to "828EL" (bisphenol A type epoxy resin), and "ZX-1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin). Added 2 parts. A resin composition 11 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 2: Preparation of resin composition 12>
In Example 1, "YX7760" (bisphenol AF type epoxy resin) was changed to "N-695" (cresol novolac type epoxy resin), and "ZX-1059" (bisphenol A type epoxy resin and bisphenol F type epoxy resin mixture) was added. A resin composition 12 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 3: Preparation of Resin Composition 13>
In Example 1, 30 parts of "YX7200B35" (phenoxy resin) were changed to 10.5 parts of "BX-5" (polyvinyl acetal resin), 29.75 parts of methyl ethyl ketone, and 29.75 parts of cyclohexanone, and "ZX-1059" ( 2 parts of a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) were added. A resin composition 13 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 4: Preparation of Resin Composition 14>
In Example 1, 30 parts of "YX7200B35" (phenoxy resin) was changed to 70 parts of "SG-P3" (epoxy group-containing acrylic acid ester copolymer resin), and "ZX-1059" (bisphenol A type epoxy resin and bisphenol 2 parts of type F epoxy resin mixture) were added. A resin composition 14 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 5: Preparation of Resin Composition 15>
In Example 1, 2 parts of "ZX-1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) were added, and 0.18 parts of "TBP-DA" (phosphonium salt) was added to "EMI24" (imidazole hardening accelerator) was changed to 0.78 parts. A resin composition 15 was prepared in the same manner as in Example 1 except for the above matters.

<Preparation of sample for transparency evaluation>
For the resin compositions 1 to 15 prepared in Examples and Comparative Examples, a PET film (“Lumirror R80” manufactured by Toray Industries, Inc., thickness 38 μm) was released with an alkyd resin-based release agent (“AL-5” manufactured by Lintec). , softening point 130 ° C.), coated with a die coater so that the thickness of the resin composition layer after drying is 60 μm, dried at 65 ° C. to 120 ° C. for 7 minutes, and a resin composition sheet (resin A composition layer (thickness: 60 μm)/laminate of release-treated PET film) was obtained. This resin composition sheet is cut into 30 mm squares, and two sheets are laminated using a vacuum laminator (V-160, manufactured by Nikko Materials Co., Ltd.) to form a resin composition layer having a thickness of 120 μm. A product sheet (laminated body of release-treated PET film/resin composition layer (thickness: 120 μm, 30 mm square)/release-treated PET film). The release-treated PET film on both sides of the resin composition sheet was peeled off, and the exposed resin composition layer was treated with a silicone-based release agent on both sides of the PET film (“E7004” manufactured by Toyobo Co., Ltd., thickness 38 μm, 50 mm square. ) was laminated. This lamination was carried out by pressure bonding for 20 seconds at 80° C. and pressure of 0.1 MPa after reducing the pressure to 5 hPa or less for 20 seconds. Thus, a resin composition sheet having a release-treated PET film on both sides of a resin composition layer having a thickness of 120 μm was obtained.

The resin composition sheet having release-treated PET films on both sides is heated at 100° C. for 60 minutes and further at 150° C. for 30 minutes to thermally cure the resin composition layer, and the support is peeled off. A 120 μm film-like cured product was obtained.

<Initial transparency evaluation test>
The parallel light transmittance of the cured film was measured using a fiber spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., MCPD-7700) equipped with a φ60 mm integrating sphere, with the distance between the integrating sphere and the sample set to 30 mm. . Air was used as a reference, and the value at 400 nm was adopted as the transmittance. Further, color calculation was performed with a viewing angle of 2 degrees and a light source of D65, and the value of b* in the L*a*b* color system was obtained.

<Heat resistance evaluation test>
After evaluating the initial transparency, the film-like cured product was allowed to stand in an oven at 110° C. for 100 hours, and the transparency was evaluated in the same manner as described above.

Regarding the parallel light transmittance, a transmittance at 400 nm of 80% or more was evaluated as good (◯), and a transmittance of less than 80% was evaluated as poor (x). A b* value of less than 1.0 was evaluated as good (◯), and a value of 1.0 or more as poor (x). In addition, as the rate of change of b*, the value of b* after 100 hours at 110 ° C./initial b* (change rate of b* value before and after storage) is less than 2.5 is good (○), 2.5 or more was regarded as defective (x).

The test results are shown in Table 1 below. In Table 1, "(A) component content (%)", "epoxy resin ((A) component + (D) component) content (%)", and "hardening accelerator ((C) component) "Content ratio" is the ratio (% by mass) to the total non-volatile content of the resin composition.

Claims (8)

Components (A) to (C) below:
(A) a bisphenol AF type epoxy resin,
(B) a thermoplastic resin containing a phenoxy resin, and (C) a resin composition containing a curing accelerator containing a phosphonium salt,
When used to form a cured product with high translucency, and when the cured product is a film-like cured product with a thickness of 120 μm, the cured product has a parallel light transmittance of 80% or more at 400 nm . , resin composition. 2. The resin according to claim 1, wherein when the cured body is a film-shaped cured body with a thickness of 120 μm, the cured body has a parallel light transmittance of 80% or more at 400 nm after being stored at 110° C. for 100 hours. Composition. 3. The resin composition according to claim 1, wherein the phosphonium salt is an ionic liquid. The resin composition according to any one of claims 1 to 3, wherein the phosphonium cation of the phosphonium salt is a tetraalkylphosphonium cation. The resin composition according to any one of claims 1 to 4, further comprising (D) an epoxy resin (excluding component (A)). The resin composition according to any one of claims 1 to 5, which is in the form of a film. A cured product of the resin composition according to any one of claims 1 to 6. 8. The cured product according to claim 7, wherein the b* value in the L*a*b* color system is less than 1.0 both before and after storage at 110[deg.] C. for 100 hours.