JP2013076097A - Curable resin composition and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition which can form cured products having sufficiently high optical transparency, excellent light resistance, excellent heat resistance, and sufficiently low elastic modulus, and has a sufficiently small cured contraction coefficient.SOLUTION: This curable resin composition contains (A) a (meth)acrylic copolymer having (meth)acryloyl groups and siloxane structures in the ester portions, (B) a siloxane structure-containing (meth)acrylate, (C) a non-silicone-based (meth)acrylate, and (D) a radical polymerization initiator.

Description

  The present invention relates to a curable resin composition and an optical member using the same.

  The curable resin composition for optical members is solvent-free and liquid at room temperature, is easy to mold and cure, and has excellent transparency, light resistance, heat resistance and mechanical properties of the cured product, and Low stress is desired. Conventionally, epoxy resin has been widely used as a resin for optical members because a mounting process on an electronic substrate or the like and heat resistance and mechanical characteristics under high-temperature operation are required. However, in recent years, the use of high-intensity laser light, blue light, and near-ultraviolet light has been spreading in the field of optical and electronic devices, and a resin that is more excellent in transparency, heat resistance, and light resistance than ever is required.

  In general, epoxy resins have high transparency in the visible range, but sufficient transparency cannot be obtained in the ultraviolet to near ultraviolet range. Moreover, there exists a problem that an epoxy resin tends to be colored with a heat | fever or light and is inferior to an optical characteristic. As a method for improving the coloring problem of the epoxy resin, for example, Patent Documents 1 and 2 below disclose a method for reducing impurities that are one of the causes of coloring contained in alicyclic bisphenol A diglycidyl ether. ing.

  In addition, it is known that the colorability of the epoxy resin is greatly affected by the type of curing accelerator in addition to the chemical structure and impurities of the epoxy monomer. For example, the use of a phosphorus curing accelerator tends to be less colored than when an amine or imidazole curing accelerator is used.

JP 2003-171439 A JP 2004-75894 A

  However, even if the methods described in Patent Documents 1 and 2 are used, improvement in the colorability of the epoxy resin is not always sufficient, and further improvement in heat resistance colorability and ultraviolet color resistance is demanded. Further, even when a phosphorus-based curing accelerator is used as the curing accelerator, the improvement of the coloring property of the epoxy resin is not always sufficient, and further improvement of the coloring resistance is demanded.

  On the other hand, acrylic resins that are generally excellent in optical properties are also used as optical member resins. However, the acrylic resin has a drawback that the curing shrinkage is large. This is because, unlike the ring-opening polymerization reaction of epoxy, in acrylate, the van der Waals distance of the monomer is reduced to the covalent bond distance by radical polymerization. Due to the curing shrinkage, a stress is generated in the cured product of the acrylic resin, and there is a problem that the adhesion to the adherend is inferior.

  The present invention has been made in view of the above-described problems of the prior art, and can form a cured product having sufficiently high optical transparency, excellent light resistance and heat resistance, and sufficiently low elastic modulus. Another object is to provide a curable resin composition having a sufficiently low cure shrinkage. Another object of the present invention is to provide an optical member comprising the curable resin composition, having sufficiently high optical transparency, excellent light resistance and heat resistance, and sufficiently low elastic modulus. To do.

  In order to achieve the above object, the present invention provides (A) a (meth) acrylic copolymer containing a (meth) acryloyl group and a siloxane structure in an ester moiety, (B) a siloxane structure-containing (meth) acrylate, A curable resin composition containing (C) a non-silicone (meth) acrylate and (D) a radical polymerization initiator is provided.

  In general, a siloxane resin has excellent light resistance and heat resistance. The curable resin composition of the present invention contains (A) (meth) acrylic copolymer having (siloxane) structure and (B) acrylate, and (C) non-silicone (meth) acrylate. In addition, a cured product having a sufficiently high optical transparency and excellent in light resistance and heat resistance can be formed. Further, due to the presence of the (A) (meth) acrylic copolymer as a polymer, the curing shrinkage rate is sufficiently high. Can be reduced. In addition, since (A) (meth) acrylic copolymer and (B) acrylate have a siloxane structure, the obtained cured product has a low elastic modulus and can relieve stress. In addition, when the cured product is formed on the adherend with the curable resin composition, the stress between the cured product and the adherend is alleviated because the cure shrinkage rate and the elastic modulus of the cured product are sufficiently low. And excellent adhesiveness can be obtained.

  As described above, the curable resin composition of the present invention has a sufficiently high optical transparency, can form a cured product excellent in heat resistance and light resistance, and is capable of reducing curing shrinkage and reducing elasticity. By realizing it, the stress can be sufficiently reduced. From the above properties, the curable resin composition of the present invention is suitable as a curable resin composition for use in electronic materials such as a sealing resin for optical semiconductors. And the lifetime and reliability of an optical element can be improved by applying the curable resin composition of this invention excellent in heat resistance and light resistance to an optical member.

  In the curable resin composition of the present invention, the weight average molecular weight of the (A) (meth) acrylic copolymer is preferably 1,000 to 10,000. Thereby, while being able to reduce cure shrinkage more fully, the hardened | cured material with more excellent optical transparency, light resistance, heat resistance, and mechanical characteristics (low elastic modulus etc.) can be formed.

  In the curable resin composition of the present invention, the (A) (meth) acrylic copolymer may contain (3-methacryloxypropyl) tris (trimethylsiloxy) silane as a monomer unit and the (A) (meth). It is preferable to contain 10 to 80% by mass based on the total amount of monomer units constituting the acrylic copolymer. Thereby, the compatibility of (A) (meth) acrylic copolymer and (B) siloxane structure-containing (meth) acrylate can be further improved, and optical transparency, light resistance, heat resistance and mechanical properties are improved. A more excellent cured product can be formed.

  Further, the curable resin composition of the present invention has (3-methacryloxypropyl) tris (trimethylsiloxy) silane as the (B) siloxane structure-containing (meth) acrylate, and 10 based on the total amount of the curable resin composition. It is preferable to contain -80 mass%. Thereby, the compatibility of (A) (meth) acrylic copolymer and (B) siloxane structure-containing (meth) acrylate can be further improved, and optical transparency, light resistance, heat resistance and mechanical properties are improved. A more excellent cured product can be formed.

  Furthermore, the curable resin composition of the present invention preferably contains a polyfunctional (meth) acrylate having a siloxane skeleton and a molecular weight of 200 to 7,000 as the (B) siloxane structure-containing (meth) acrylate. Thereby, the crosslinking density of the hardened | cured material obtained can be raised more, and a mechanical characteristic can be improved more. In particular, as (B) siloxane structure-containing (meth) acrylate, by using the (3-methacryloxypropyl) tris (trimethylsiloxy) silane and the polyfunctional (meth) acrylate in combination, the polyfunctional (meth) acrylate Decrease in transparency of the cured product due to the addition of can be sufficiently suppressed, and a cured product having excellent optical transparency and excellent mechanical properties can be obtained.

  The present invention also provides an optical member comprising a cured product obtained by curing the curable resin composition of the present invention. Since such an optical member is formed using the curable resin composition of the present invention, sufficiently high optical transparency, excellent light resistance and heat resistance, and sufficiently low elastic modulus are obtained. Can do.

  According to the present invention, a curable resin composition having a sufficiently high optical transparency, excellent light resistance and heat resistance, and capable of forming a cured product having a sufficiently low elastic modulus and a sufficiently low curing shrinkage rate. Things can be provided. In addition, according to the present invention, it is possible to provide an optical member using the curable resin composition, which has sufficiently high optical transparency, excellent light resistance and heat resistance, and sufficiently low elastic modulus. it can.

It is a schematic end view which shows one Embodiment of the optical semiconductor element provided with the optical member of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. In the present specification, “(meth) acrylic acid” means “acrylic acid” and “methacrylic acid” corresponding thereto, and “(meth) acrylic copolymer” means “acrylic copolymer” and The corresponding “methacrylic copolymer” means “(meth) acrylate” means “acrylate” and the corresponding “methacrylate”, “(meth) acryloyl group” means “acryloyl group” and The corresponding “methacryloyl group” is meant.

  The curable resin composition of the present invention comprises (A) a (meth) acrylic copolymer having a (meth) acryloyl group and a siloxane structure in the ester portion (hereinafter, sometimes referred to as “component (A)”), and (B ) Siloxane structure-containing (meth) acrylate (hereinafter sometimes referred to as “component (B)”), (C) non-silicone (meth) acrylate (hereinafter sometimes referred to as “(C) component”), and (D ) Radical polymerization initiator (hereinafter sometimes referred to as “component (D)”). Such a curable resin composition of the present invention is preferably liquid at room temperature (25 ° C.), and is preferably cured by heating or light irradiation. The conventional acrylic resin has a problem that the curing shrinkage rate is large and a large stress is generated upon curing. However, the curable resin composition of the present invention is a low molecular weight polymer (A) (meta ) By containing an acrylic copolymer, the curing shrinkage can be sufficiently reduced, and the stress can be reduced.

  The (meth) acrylic copolymer as the component (A) preferably has a weight average molecular weight of 1,000 to 10,000, more preferably 2,000 to 8,000. When the weight average molecular weight is less than 1,000, the mechanical properties and optical properties of the resulting cured product tend to decrease. When the weight average molecular weight exceeds 10,000, the viscosity increases and compatibility with other polymerization components is increased. It tends to decrease.

  The (A) (meth) acrylic copolymer preferably contains (3-methacryloxypropyl) tris (trimethylsiloxy) silane as a monomer unit. By including this siloxane-containing methacrylate as a monomer unit, the compatibility between (A) (meth) acrylic copolymer and (B) siloxane structure-containing (meth) acrylate can be further improved.

  (A) (3-Methacryloxypropyl) tris (trimethylsiloxy) silane contained in the (meth) acrylic copolymer is 10 to 10 based on the total amount of monomer units constituting the (A) (meth) acrylic copolymer. It is preferable that it is 80 mass%, and it is more preferable that it is 20-70 mass%. When this amount exceeds 80% by mass, the number of (meth) acryloyl groups in the (A) (meth) acrylic copolymer tends to be small, and the crosslinking density of the cured product tends to be insufficient, and 10% by mass. If it is less than this, the compatibility between the component (A) and the component (B) tends to decrease.

  The (A) (meth) acrylic copolymer is, for example, an epoxy group-containing (meth) acrylate, (3-methacryloxypropyl) tris (trimethylsiloxy) silane, and one (meth) acryloyl group in one molecule. And a compound having an epoxy group-containing copolymer after copolymerization with a known method such as a solution polymerization method in the presence of a radical polymerization initiator, and further with an epoxy group in the copolymer ( It can be obtained by reacting with (meth) acrylic acid. Thus, the (A) (meth) acrylic copolymer is preferably obtained using an epoxy group-containing (meth) acrylate. And the (A) component which has a (meth) acryloyl group can be easily obtained by making this epoxy group and compounds, such as carboxylic acid containing a (meth) acryloyl group, react.

A more specific example of the synthesis method of (A) (meth) acrylic copolymer is as follows. First, a solvent is put in a reaction vessel and heated to about 140 ° C. with stirring under a pressure condition of about 0.15 MPa (1.5 kgf / cm ² ) in a nitrogen gas atmosphere. Next, epoxy group-containing (meth) acrylate, (3-methacryloxypropyl) tris (trimethylsiloxy) silane, a compound having one (meth) acryloyl group in one molecule, and radical polymerization initiation in a heated solvent A mixed solution composed of an agent is uniformly added dropwise, and after completion of the addition, the reaction is further continued to obtain an epoxy group-containing copolymer. And a (meth) acryl copolymer can be obtained by making the epoxy group and (meth) acrylic acid in the obtained epoxy group containing copolymer react.

  Here, the epoxy group-containing (meth) acrylate is not particularly limited. For example, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, 1,4-hydroxybutyl acrylate glycidyl. Examples include ether. Among these, glycidyl methacrylate is preferable.

  As the radical thermal polymerization initiator, any one that can be used for ordinary radical polymerization, such as an azo initiator and a peroxide initiator, can be used. Examples of the azo initiator include azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, and the like. Examples of the peroxide initiator include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-t- Examples include butylperoxy-3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, and di-t-hexyl peroxide.

  Furthermore, the compounding ratio of the epoxy group-containing copolymer and (meth) acrylic acid is such that the equivalent ratio of epoxy group to carbonyl group (epoxy group in copolymer / carbonyl group in (meth) acrylic acid) is 0. It is preferable to mix | blend so that it may become 95-1.1. If this blending ratio is less than 0.95, the mechanical properties of the resulting cured product tend to be lowered due to the effect of excessive (meth) acrylic acid, and if it exceeds 1.1, the resin composition obtained There is a general tendency for curability and storage stability to decrease. The reaction between the epoxy group-containing copolymer and (meth) acrylic acid is, for example, a basic catalyst such as N, N′-diethylcyclohexylamine, triethylamine, or triethanolamine, or a phosphorus catalyst such as triphenylphosphine. Can be carried out by reacting at about 105 ° C. for 8 to 10 hours.

  (A) The weight average molecular weight of the (meth) acrylic copolymer is preferably 1,000 to 10,000 as described above, but as a method for producing a copolymer having a weight average molecular weight in this range. Examples of the method include a method using a chain transfer agent, a method of adding a large amount of a radical polymerization initiator, and a method of performing a reaction under higher temperature conditions. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve. The measurement conditions are as follows, for example.

(GPC conditions)
Equipment used: Hitachi L-6000 (trade name, manufactured by Hitachi, Ltd.)
Column: Gel pack GL-R420 + Gel pack GL-R430 + Gel pack GL-R440 (3 in total) [all manufactured by Hitachi Chemical Co., Ltd., trade name]
Eluent: tetrahydrofuran,
Measurement temperature: 40 ° C.
Flow rate: 1.75 ml / min. ,
Detector: L-3300RI [Hitachi Ltd., brand name].

  In the present invention, the (A) (meth) acrylic copolymer is preferably obtained by further purifying the (meth) acrylic copolymer synthesized by the method described above. By performing the purification, it is possible to further improve the light resistance and heat-resistant colorability of the obtained cured product. As a purification method, a known purification method can be used. For example, it can be purified by a reprecipitation method. As a more specific example of the purification method, a solution of the low molecular weight acrylic copolymer obtained by the above-described synthesis method is stirred in a 10-fold amount of a poor solvent (methanol: water = 50: 50). After dropping, the supernatant is removed to obtain a precipitate. Next, the purified (A) (meth) acrylic copolymer can be obtained by dissolving the precipitate with a solvent, dehydrating with magnesium sulfate, filtering, and removing the filtrate from the solvent.

  The (B) component siloxane structure-containing (meth) acrylate preferably contains (3-methacryloxypropyl) tris (trimethylsiloxy) silane. The (B) siloxane structure-containing (meth) acrylate preferably contains a polyfunctional (meth) acrylate having a siloxane skeleton and a molecular weight of 200 to 7,000. (B) Since the siloxane structure-containing (meth) acrylate contains the (3-methacryloxypropyl) tris (trimethylsiloxy) silane, a highly transparent cured product can be obtained even when the polyfunctional (meth) acrylate is added. In addition, the inclusion of the polyfunctional (meth) acrylate increases the crosslink density, and a cured product having excellent mechanical properties can be obtained. In particular, in the curable resin composition of the present invention, (3-methacryloxypropyl) tris (as a component of the (A) (meth) acrylic copolymer and (B) siloxane structure-containing (meth) acrylate described above. By using (trimethylsiloxy) silane, it becomes possible to add a siloxane-containing polyfunctional (meth) acrylate as the component (B), and the above effect can be effectively obtained.

  In the curable resin composition of the present invention, the content of the (3-methacryloxypropyl) tris (trimethylsiloxy) silane as the component (B) is 10 to 80% by mass based on the total amount of the curable resin composition. It is preferable and it is more preferable that it is 20-70 mass%. When this content exceeds 80 mass%, it exists in the tendency which cannot fully utilize the effect of the cure shrinkage reduction by (A) component. On the other hand, when the content is less than 10% by mass, the effect of lowering the modulus of elasticity due to the component (B) is lowered and the optical characteristics tend to be lowered.

  The polyfunctional (meth) acrylate as the component (B) preferably has a molecular weight of 200 to 7,000, more preferably 500 to 5,000. If the molecular weight is less than 200, the elastic modulus tends not to be sufficiently lowered. If the molecular weight exceeds 7,000, the compatibility is lowered and the transparency of the cured product tends to be lowered.

  Although it does not specifically limit as siloxane containing polyfunctional (meth) acrylate, For example, the compound (dimethacrylate) etc. which have a structure represented by following General formula (1) are mentioned. These can be used individually by 1 type or in combination of 2 or more types.

［式中、ｎは０〜２００の整数を示し、Ｒは水素原子、炭素原子１〜９のアルキル基又はアリール基を示し、Ｒ’はアルキレン基を示す。なお、同一分子中の複数のＲ及びＲ’は同一でも異なっていてもよい。］

[Wherein n represents an integer of 0 to 200, R represents a hydrogen atom, an alkyl group having 1 to 9 carbon atoms or an aryl group, and R ′ represents an alkylene group. A plurality of R and R ′ in the same molecule may be the same or different. ]

  The curable resin composition of the present invention contains a non-silicone (meth) acrylate having no siloxane structure as the component (C). Examples of the (C) non-silicone (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and t-butyl (meth). Acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) Acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, stearyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, ethoxyethyl (meth) acrylate , Butoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-methoxyethoxy (meth) acrylate, 2-ethoxyethoxy (meth) ) Acrylate, pyrenoxide adduct (meth) acrylate, octafluoropentyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, cyclohexyl mono (meth) acrylate, tri Mono (meth) acrylate having cyclodecane, ethylene glycol di (meth) acrylate, methanediol di (meth) acrylate, 1,2-ethanediol di (meth) acrylate, 1,3-butanedi Di (meth) acrylate, 1,3-propanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di ( (Meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) Acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, neopentyl di (meth) acrylate, dimethylol tricyclode Candi (meth) acrylate, zinc di (meth) acrylate, 2- (meta And acryloyloxyethyl acid phosphate, caprolactone-modified tricyclodecane dimethanol di (meth) acrylate, and the like. Among these, glycidyl methacrylate is preferable. These can be used individually by 1 type or in combination of 2 or more types.

  As the radical polymerization initiator as component (D), any one that can be used for ordinary radical polymerization, such as an azo initiator or a peroxide initiator, can be used. Examples of the azo initiator include azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, and the like. Examples of the peroxide initiator include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-t- Examples include butyl peroxy-3,3,5-trimethylcyclohexane, t-butyl peroxyisopropyl carbonate, and the like.

  In addition, when radical polymerization is performed by photoradical polymerization, a photoradical polymerization initiator is used as a radical polymerization initiator in place of the above-described radical thermal polymerization initiator such as an azo-based initiator or a peroxide initiator. be able to. The radical photopolymerization initiator is not particularly limited as long as it efficiently absorbs and activates the ultraviolet rays of an industrial UV irradiation apparatus and does not yellow the cured resin. For example, 1-hydroxycyclohexyl phenyl ketone 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-methyl-1-phenyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- ( 1-methylvinyl) phenyl) propanone, a mixture of oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone and tripropylene glycol diacrylate, and oxy-phenyl-acetate Tic acid-2- (2-oxo-2-phenyl-acetoxy-ethoxy) -ethyl ester and oxy-phenol Le - acetone tic acid 2- (2-hydroxy - ethoxy) - mixture of ethyl esters.

  In the curable resin composition of the present invention, the content of the (A) (meth) acrylic copolymer is preferably 10 to 70% by mass based on the total amount of the curable resin composition, and is preferably 20 to 60% by mass. It is more preferable that If this content exceeds 70% by mass, the effect of lowering the elastic modulus and the optical properties tend to be lowered, and if it is less than 10% by mass, the curing shrinkage tends to be insufficiently reduced.

  Moreover, in the curable resin composition of this invention, it is preferable that content of (B) siloxane structure containing (meth) acrylate is 10-80 mass% on the basis of the curable resin composition whole quantity, and 20-70. More preferably, it is mass%. If this content exceeds 80% by mass, the curing shrinkage tends to increase, and if it is less than 10% by mass, the effect of lowering the elastic modulus and the optical properties tend to decrease.

  In the curable resin composition of the present invention, the content of (C) the non-silicone (meth) acrylate is preferably 5 to 50% by mass based on the total amount of the curable resin composition, and 10 to 40 More preferably, it is mass%. If this content exceeds 50% by mass, the effect of lowering the elastic modulus and the optical properties tend to be reduced, and if it is less than 5% by mass, the effect of the component (C) tends to be insufficient.

  Furthermore, in the curable resin composition of the present invention, the content of the (D) radical polymerization initiator is based on 100 parts by mass of the total amount of the acrylate components (component (A), component (B) and component (C)). It is preferable to set it as 0.01-5 mass parts, and it is especially preferable to set it as 0.1-1 mass part. If this content exceeds 5 parts by mass, the resulting cured product tends to be colored by heat or ultraviolet rays, and if it is less than 0.01 part by mass, the resin composition tends to be difficult to cure.

  In addition to the components (A) to (D), the curable resin composition of the present invention further includes a hindered amine light stabilizer, a phenolic or phosphorus antioxidant, an ultraviolet absorber, an inorganic filler, an organic filler. Fillers, coupling agents, polymerization inhibitors and the like can be added. Moreover, a mold release agent, a plasticizer, an antistatic agent, a flame retardant, etc. may be added from the viewpoint of moldability. These are preferably liquid from the viewpoint of ensuring the light transmittance of the obtained resin cured product, but in the case of a solid, it is desirable to have a particle size equal to or smaller than the wavelength used.

  Next, the optical member of the present invention will be described. The optical member of the present invention is composed of a cured product obtained by curing the above-described curable resin composition of the present invention.

  Since the optical member of the present invention is formed using the curable resin composition of the present invention described above, the optical transparency is sufficiently high, and the light resistance, heat resistance and mechanical properties are excellent. Examples of the optical member of the present invention include optical members for optical semiconductor elements such as transparent substrates, lenses, adhesives, optical waveguides, light emitting diodes (LEDs), phototransistors, photodiodes, and solid-state imaging devices.

  As a method for producing an optical member using the curable resin composition of the present invention, for example, a solution of the curable resin composition is poured into a desired portion, poured, potted, or poured into a mold and cured by heating or light irradiation. A method is mentioned. Further, it is desirable to reduce the oxygen concentration in the curable resin composition in advance by nitrogen bubbling in order to inhibit curing and prevent coloring.

  The curing conditions in the case of thermosetting are not particularly limited as long as it is a temperature and a time at which radical polymerization is finally completed, although it depends on the type, combination and addition amount of each component. It is about 3 to 6 hours at ° C. Moreover, in order to reduce the internal stress generated by the rapid curing reaction, it is desirable to raise the curing temperature stepwise. Furthermore, in order to easily obtain a cured product in a shorter time, it is possible to carry out photo radical polymerization by light irradiation.

  FIG. 1 is a schematic end view showing an embodiment of an optical semiconductor device provided with the optical member of the present invention. An optical semiconductor element 100 shown in FIG. 1 is a mounting type light emitting diode including a light emitting diode element 2 and a transparent optical member 1 provided so that the light emitting diode element 2 is sealed. The light emitting diode element 2 is arranged at the bottom of the cavity 10 formed in the case member 5. The light emitting diode element 2 is bonded to the case member 5 via an adhesive layer 20 and connected to the lead frame 7 via a wire 8.

  The optical member 1 covers the light emitting diode element 2 and fills the cavity 10. The optical member 1 is formed by, for example, a method in which the solution of the curable resin composition described above is poured into the cavity 10 and the curable resin composition in the cavity 10 is cured by the above-described heating or light irradiation. .

  The curable resin composition of the present invention described above is a resin composition having a sufficiently low cure shrinkage, sufficiently high optical transparency of the cured product, and excellent heat resistance, light resistance, and mechanical properties. The cured product is suitable as an optical member for use in an optical semiconductor device such as a transparent substrate, a lens, an adhesive, an optical waveguide, a light emitting diode (LED), a phototransistor, a photodiode, and a solid-state imaging device.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(Production Example 1)
101 parts by mass of toluene was put in a reaction vessel, and heated to 140 ° C. with stirring under a pressure condition of 0.15 MPa (1.5 kgf / cm ² ) in a nitrogen gas atmosphere. (A) 20.4 parts by mass of glycidyl methacrylate, (b) 3.6 parts by mass of methyl methacrylate, (c) (3-methacryloxypropyl) tris (trimethylsiloxy) silane 76.0 parts by mass in this 140 ° C. toluene. And 114 parts by mass of a component consisting of 14 parts by mass of perhexyl D (manufactured by NOF Corporation) as a radical polymerization initiator was added dropwise over 2 hours. After completion of dropping, the reaction was continued for another 4 hours to synthesize a copolymer. The molar ratio of each monomer component of the obtained copolymer was (a) / (b) / (c) = 40/10/50, and the weight average molecular weight was 2,000.

  Next, 10.7 parts by mass of acrylic acid, 1 part by mass of triphenylphosphine, and 0.3 parts by mass of hydroquinone monomethyl ether are added to 214 parts by mass of this copolymer, and at 100 ° C. while blowing air at atmospheric pressure. The mixture was heated and stirred for 10 hours to obtain a solution (solid content: 50% by mass) of a methacrylic copolymer (acid value: 1.5 mgKOH / g) having an acryloyl group and a siloxane structure in the ester portion.

  Further, this methacrylic copolymer solution was dropped into a 10-fold amount of a poor solvent (methanol: water = 50: 50) while stirring and allowed to stand for several hours, and then the supernatant was removed to obtain a precipitate. Obtained. The obtained precipitate was dissolved in tetrahydrofuran (THF), dehydrated with magnesium sulfate, and then filtered. The solution was desolvated with an evaporator until the toluene content became 1% by mass or less to obtain a purified methacrylic copolymer (A1).

(Production Example 2)
101 parts by mass of toluene was put in a reaction vessel, and heated to 140 ° C. with stirring under a pressure condition of 0.15 MPa (1.5 kgf / cm ² ) in a nitrogen gas atmosphere. In the toluene at 140 ° C., (a) 58.7 parts by mass of glycidyl methacrylate, (b) 41.3 parts by mass of methyl methacrylate, and (d) perhexyl D (manufactured by NOF Corporation) 14 as a radical polymerization initiator. 114 parts by mass of a component composed of a part by mass was uniformly dropped over 2 hours. After completion of the dropwise addition, the reaction was further continued for 4 hours to synthesize a copolymer. The molar ratio of each monomer component of the obtained copolymer was (a) / (b) = 50/50, and the weight average molecular weight was 2,000.

  Next, 30.7 parts by mass of acrylic acid, 1 part by mass of triphenylphosphine and 0.3 part by mass of hydroquinone monomethyl ether are added to 214 parts by mass of the copolymer, and the mixture is heated and stirred under the same conditions as in Production Example 1. Thus, a solution (solid content 50% by mass) of a methacrylic copolymer having an acryloyl group in the ester portion (acid value: 1.5 mgKOH / g) was obtained. Further, this methacrylic copolymer solution was purified by the same method as in Production Example 1 to obtain a methacrylic copolymer (A2).

Example 1
30 parts by weight of the methacrylic copolymer (A1) obtained in Production Example 1 as the component (A), (3-methacryloxypropyl) tris (trimethylsiloxy) silane (Silaplane TM-0701T, Chisso Corporation) as the component (B) 30 parts by mass), 20 parts by mass of siloxane structure-containing dimethacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.), 20 as glycidyl methacrylate (light ester G, manufactured by Kyoeisha Chemical Co., Ltd.) 20 0.5 parts by mass of lauroyl peroxide (Perroyl L, manufactured by NOF Corporation) and t-butylperoxy-2-ethylhexanoate (Perbutyl I, NOF Corporation) as component (D) (Manufactured) 0.5 parts by mass was mixed at room temperature (25 ° C.) to prepare a liquid curable resin composition solution.

  This curable resin composition solution was poured into a mold in which 3 mm thick and 1 mm thick silicone spacers were sandwiched between glass plates, and each was carried out in an oven at 80 ° C., 100 ° C., 120 ° C. and 140 ° C. for 1 hour ( It was heated under the conditions of 4 hours in total, and 3 mm thick and 1 mm thick resin cured products were obtained.

(Example 2)
20 parts by mass of the methacrylic copolymer (A1) obtained in Production Example 1, 30 parts by mass of (3-methacryloxypropyl) tris (trimethylsiloxy) silane (Silaplane TM-0701T, manufactured by Chisso Corporation), a siloxane-containing diester 30 parts by mass of methacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.), 20 parts by mass of glycidyl methacrylate (light ester G, manufactured by Kyoeisha Chemical Co., Ltd.), lauroyl peroxide (Perroyl L, manufactured by Nippon Oil & Fats Co., Ltd.) 0 .5 parts by mass and 0.5 parts by mass of t-butyl peroxy-2-ethylhexanoate (Perbutyl I, manufactured by NOF Corporation) at room temperature (25 ° C.) to form a liquid curable resin A composition solution was prepared. Using this curable resin composition solution, resin cured products having thicknesses of 3 mm and 1 mm were obtained in the same manner as in Example 1.

(Example 3)
30 parts by mass of the methacrylic copolymer (A1) obtained in Production Example 1, 30 parts by mass of (3-methacryloxypropyl) tris (trimethylsiloxy) silane (Silaplane TM-0701T, manufactured by Chisso Corporation), siloxane-containing diester 20 parts by mass of methacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.), 20 parts by mass of glycidyl methacrylate (Light Ester G, manufactured by Kyoeisha Chemical Co., Ltd.), and 1-hydroxycyclohexylphenyl which is a radical photopolymerization initiator One part by weight of ketone (IRGACURR 184, manufactured by Ciba Specialty Chemicals) was mixed at room temperature (25 ° C.) to prepare a liquid curable resin composition solution.

This curable resin composition solution was poured into a mold in which 3 mm thick and 1 mm thick silicone spacers were sandwiched between glass plates, and using an ultrahigh pressure mercury lamp, the illuminance was 11.6 mW / cm ² and the cumulative exposure amount was 3000 mJ. The resin was exposed to / cm ² and radically polymerized to obtain resin cured products having a thickness of 3 mm and 1 mm.

(Comparative Example 1)
20 parts by mass of glycidyl methacrylate (light ester G, manufactured by Kyoeisha Chemical Co., Ltd.), 40 parts by mass of (3-methacryloxypropyl) tris (trimethylsiloxy) silane (Silaplane TM-0701T, manufactured by Chisso Corporation), 40 parts by mass of methacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1 part by mass of 1-hydroxycyclohexyl phenyl ketone (IRGACURR 184, manufactured by Ciba Specialty Chemicals) at room temperature (25 ° C.) By mixing, a liquid curable resin composition solution was prepared. Using this curable resin composition solution, resin cured products having a thickness of 3 mm and 1 mm were obtained in the same manner as in Example 3.

(Comparative Example 2)
40 parts by mass of the methacrylic copolymer (A2) having no siloxane structure obtained in Production Example 2, (3-methacryloxypropyl) tris (trimethylsiloxy) silane (Silaplane TM-0701T, manufactured by Chisso Corporation) 40 Parts by mass, 20 parts by mass of siloxane-containing dimethacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.5 parts by mass of lauroyl peroxide (Perroyl L, manufactured by NOF Corporation), and t-butyl per 0.5 parts by mass of oxy-2-ethylhexanoate (Perbutyl I, manufactured by NOF Corporation) was mixed at room temperature (25 ° C.) to prepare a liquid curable resin composition solution. It was not a bad clear solution.

(Comparative Example 3)
10 parts by mass of the methacrylic copolymer (A1) obtained in Production Example 1, 90 parts by mass of siloxane-containing dimethacrylate (X-22-164A, manufactured by Shin-Etsu Chemical Co., Ltd.), lauroyl peroxide (Parroyl L, Nippon Oil & Fats Co., Ltd.) 0.5 parts by mass) and 0.5 parts by mass of t-butyl peroxy-2-ethylhexanoate (Perbutyl I, manufactured by NOF Corporation) at room temperature (25 ° C.) Although a curable resin composition solution was prepared, the compatibility was poor and the solution was not transparent.

(Comparative Example 4)
90 parts by mass of hydrogenated bisphenol A glycidyl ether (Denacol EX-252, manufactured by Nagase ChemteX Corporation), 10 parts by mass of CEL2021 (manufactured by Daicel Chemical Industries, Ltd.), methylhexahydrophthalic anhydride (HN-5500F, Hitachi Chemical) 90 parts by mass) and 1 part by mass of tetrabutylphosphonium diethylphosphodithionate (Hishicolin PX-4ET, manufactured by Nippon Chemical Industry Co., Ltd.) as an epoxy curing accelerator are mixed at room temperature (25 ° C.), and liquid A curable resin composition solution was prepared. Using this curable resin composition solution, in the same manner as in Example 1 except that heating in the oven was performed at 80 ° C., 100 ° C., 120 ° C. and 150 ° C. for 1 hour each (total 4 hours). Resin cured products with a thickness of 3 mm and 1 mm were obtained.

  The formulations of Examples 1 to 3 and Comparative Examples 1 to 3 are summarized in Table 1.

  The numbers in Table 1 indicate parts by mass, A1: methacrylic copolymer obtained in Production Example 1, A2: methacrylic copolymer obtained in Production Example 2, B1: (3-methacryloxypropyl) tris ( Trimethylsiloxy) silane, B2: siloxane structure-containing dimethacrylate, C: glycidyl methacrylate, D1: lauroyl peroxide, D2: t-butylperoxy-2-ethylhexanoate, D3: 1-hydroxycyclohexyl phenyl ketone .

(Characteristic evaluation of cured resin)
About the resin hardened | cured material obtained in the said Examples 1-3, the comparative examples 1 and 4, the cure shrinkage rate, the bending elastic modulus, the light transmittance, and the yellowing degree were measured by the method shown below.

The cure shrinkage ratio (ΔV) is calculated from the following formula based on the specific gravity (ρ _m ) of the curable resin composition solution and the specific gravity (ρ _p ) of the resin cured product:
ΔV (%) = {(ρ _m −ρ _p ) / ρ _p } × 100
It calculated using. Here, the specific gravity of the curable resin composition solution was measured by a pycnometer method. The specific gravity of the cured resin was measured by Archimedes method using an electronic hydrometer (SD-200L, manufactured by Mirage).

  The flexural modulus was cut from a 3 × 20 × 50 mm test piece from a 3 mm thick resin cured product, and JIS-K was used for this test piece using a three-point bending test apparatus (Instron, Model 5548). A bending test with a three-point support in accordance with -6911 was conducted, and the calculation was made from the following formula (I). The bending test was performed under the conditions that the distance between fulcrums was 24 mm, the crosshead moving speed was 0.5 mm / min, and the measurement temperature was room temperature (25 ° C.).

［式（Ｉ）中、Ｅｆ：曲げ弾性率（ＭＰａ）、Ｌｖ：支点間距離（ｍｍ）、Ｐ：加重（Ｎ）、Ｙ：変位量（ｍｍ）、Ｗ：試験片の幅（ｍｍ）、ｈ：試験片の厚さ（ｍｍ）である。］

[In formula (I), Ef: flexural modulus (MPa), Lv: distance between fulcrums (mm), P: weight (N), Y: displacement (mm), W: width of test piece (mm), h: Thickness (mm) of the test piece. ]

  The light transmittance and the yellowing degree were measured using a spectrophotometer (Hitachi spectrophotometer V-3310) as a 1 mm thick resin cured product. The light transmittance was measured after the light transmittance at a wavelength of 400 nm was left at high temperature for 72 hours at 150 ° C. after curing (initial stage) and evaluation of heat discoloration. Moreover, the yellowing degree (YI) which shows yellowishness calculated | required tristimulus value XYZ in the case of the standard light C using the measured transmission spectrum, and calculated | required from following formula (II).

The light resistance test and evaluation were performed as follows. That is, a 1 mm thick resin cured product is irradiated with near-ultraviolet light for 30 hours (irradiation wavelength 365 nm, illuminance 5000 mW / cm ² , spot UV irradiation apparatus SP-7, manufactured by Ushio Inc.), and light having a wavelength of 380 nm in the irradiated portion is irradiated. The transmittance was measured.

  In Comparative Examples 2 and 3, the compatibility of the curable resin composition solution was poor, and a transparent and uniform cured product could not be obtained. Therefore, the curing shrinkage rate, bending elastic modulus, light transmittance, yellowing degree, and light resistance were not evaluated.

  Curing shrinkage of the above Examples 1 to 3 and Comparative Examples 1 and 4, bending elastic modulus at room temperature (25 ° C.), optical properties, ie, light transmittance at a wavelength of 400 nm after curing (initial) and after standing at high temperature, and The degree of yellowing is shown in Table 2.

  As is apparent from the results shown in Table 2, in Examples 1 to 3, it was confirmed that the curing shrinkage was smaller than that in Comparative Example 1. Moreover, in Examples 1-3, the bending elastic modulus in room temperature (25 degreeC) was also sufficiently small as 10 Mpa or less, and it was confirmed that a stress can be remarkably reduced with hardening shrinkage reduction. Further, in Examples 1 to 3, it was confirmed that the light transmittance after being left at a high temperature was sufficiently high, the degree of yellowing was sufficiently small, and the heat discoloration was excellent as compared with Comparative Example 4. Further, in Examples 1 to 3, it was confirmed that the light transmittance after irradiation with near-ultraviolet light was higher than that of Comparative Example 4, and the light resistance was excellent. In Comparative Examples 2 and 3, the compatibility of the materials was poor, and a transparent cured product could not be obtained.

DESCRIPTION OF SYMBOLS 1 ... Optical member, 2 ... Light emitting diode element, 5 ... Case member, 7 ... Lead frame, 8 ... Wire, 10 ... Cavity, 100 ... Optical semiconductor element.

Claims (6)

(A) a (meth) acrylic copolymer having a (meth) acryloyl group and a siloxane structure in the ester moiety;
(B) a siloxane structure-containing (meth) acrylate,
(C) a non-silicone (meth) acrylate;
(D) a radical polymerization initiator;
A curable resin composition containing   The curable resin composition according to claim 1, wherein the (A) (meth) acrylic copolymer has a weight average molecular weight of 1,000 to 10,000.   The (A) (meth) acrylic copolymer has (3-methacryloxypropyl) tris (trimethylsiloxy) silane as a monomer unit, and is based on the total amount of monomer units constituting the (A) (meth) acrylic copolymer. The curable resin composition according to claim 1, comprising 10 to 80% by mass.   The (B) siloxane structure-containing (meth) acrylate contains (3-methacryloxypropyl) tris (trimethylsiloxy) silane in an amount of 10 to 80% by mass based on the total amount of the curable resin composition. The curable resin composition as described in any one of them.   Curability as described in any one of Claims 1-4 containing the polyfunctional (meth) acrylate of the molecular weight 200-7,000 which has a siloxane skeleton as said (B) siloxane structure containing (meth) acrylate. Resin composition. The optical member which consists of hardened | cured material which hardened | cured the curable resin composition as described in any one of Claims 1-5.

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