WO2012081393A1

WO2012081393A1 - Curable composition and cured resin

Info

Publication number: WO2012081393A1
Application number: PCT/JP2011/077503
Authority: WO
Inventors: 竹中啓起; 久保隆司
Original assignee: 株式会社ダイセル
Priority date: 2010-12-14
Filing date: 2011-11-29
Publication date: 2012-06-21
Also published as: TWI518132B; TW201231544A; JP2012140607A; JP5913944B2

Abstract

Provided is a curable composition which, before being cured, has a low viscosity and therefore exhibits excellent fluidity, and which can be speedily cured by heating to form a cured resin that is inhibited from causing blur of light (chromatic aberration) and that exhibits excellent transparency and heat resistance. This curable composition is characterized by comprising (A) an epoxy compound in which an aliphatic ring is bonded to an epoxy group by a single bond or with a connecting group therebetween and which has no ester bond and (B) an epoxy compound which has both an aliphatic ring and an ester bond at an (A)/(B) weight ratio of 5/95 to 50/50.

Description

Curable composition and cured resin

The present invention relates to a heat-resistant transparent resin composition having fast curability, a cured resin thereof, and an optical member made of the cured resin. More specifically, a resin composition that has low viscosity, excellent workability, and can be quickly cured by heating to form a cured resin having excellent heat resistance and transparency, and the resin composition is cured. And an optical member such as a lens made of the cured resin.

Epoxy resins are known as resins that excel in electrical properties, moisture resistance, heat resistance, etc., and plastic materials include mechanical component materials, electrical / electronic component materials, automotive component materials, civil engineering and building materials, molding materials, paints, and adhesives. In recent years, it has attracted attention as a material for optical members such as lenses.

In particular, a cured resin obtained by curing a bisphenol-type epoxy resin is widely used as an optical semiconductor sealing material because it is excellent in electrical characteristics, moisture resistance, heat resistance and transparency. However, when used as a material for an optical member such as a lens, it cannot be said that the heat resistance is sufficient, and the shape may change at a high temperature or the light transmittance may be significantly reduced. Therefore, for example, camera-equipped mobile phones and the like are manufactured through a reflow soldering process (mounting process), but cannot withstand the process temperature (about 260 ° C.), and thus are manufactured separately after the soldering process. A process for connecting the camera module with a connector is required, and solder reflow heat resistance is required.

As a method for improving the heat resistance, a method for improving the heat resistance by increasing the epoxy group density of the epoxy compound to increase the crosslinking density is known. As a method of increasing the epoxy group density of an epoxy compound, since most of bisphenol type epoxy compounds are bifunctional epoxy compounds, a part of the bisphenol type epoxy compound is replaced with a compound having a higher epoxy group density of three or more functions. There are known a method (Patent Documents 1 and 2) and a method of increasing the epoxy group density per unit amount by reducing the repeating unit of bisphenol (Patent Document 3). However, since it contains a bisphenol-type epoxy compound having an aromatic ring in the molecule, the crosslink density does not increase so much due to the rigid structure of the aromatic ring, and it has not been sufficient in terms of heat resistance. In addition, since the aromatic ring absorbs light having a short wavelength, there are problems such as a decrease in optical characteristics and a tendency to light degradation.

On the other hand, as an epoxy compound that does not contain an aromatic ring, an invention using a hydrogenated bisphenol-type epoxy compound obtained by hydrogenating using a bisphenol-type epoxy compound as a raw material and using a catalyst such as rhodium is known ( Patent Documents 4 and 5). In addition, in materials for optical members such as lenses, there is a problem of suppressing light bleeding (chromatic aberration) caused by light being dispersed through the lens or the like, and as a method for reducing light bleeding (chromatic aberration). A method using an alicyclic epoxy compound having an Abbe number of 45 or more such as a hydrogenated bisphenol type epoxy compound is known (Patent Document 6). However, it is difficult to completely eliminate the aromatic ring of the bisphenol-type epoxy compound by hydrogenation, and since the catalyst and by-products used in the reaction are mixed, the resin obtained by curing is transparent in terms of transparency. In addition, there is a problem, and even if a hydrogenated bisphenol type epoxy compound is used instead of the bisphenol type epoxy compound, the epoxy group density does not change, so that a problem remains in terms of heat resistance.

Furthermore, bisphenol-type epoxy compounds and hydrogenated bisphenol-type epoxy compounds are often semi-solid or solid at room temperature (25 ° C.) and have low fluidity, so it is difficult to inject them quickly and uniformly into a mold or the like. It was. In particular, it was difficult to use in a casting method that requires higher fluidity during casting. Therefore, it is often used by diluting with a solvent typified by toluene, xylene, methyl ethyl ketone, ethyl acetate, etc. to lower the viscosity of the curable composition, but there is a problem that the solvent foams, There have been many problems in using the diluted curable composition for applications such as mold molding.

Patent Documents 7 and 8 describe inventions using a 3,4,3 ', 4'-diepoxycyclohexyl compound as a curable compound. However, since the compound itself is colored, there is a problem that the transparency of the cured resin composed of the compound is lowered.

JP-A-5-32866 Japanese Patent Laid-Open No. 7-165884 JP-A-5-326756 JP 2003-277473 A JP 2005-120357 A JP 2008-133439 A JP 2008-189698 A JP 2008-189853 A

Therefore, the object of the present invention is to have low viscosity and excellent fluidity before curing, to cure quickly by heating, to suppress the occurrence of light bleeding (chromatic aberration), and to have excellent transparency and heat resistance. It is providing the curable composition which can form curable resin.

Another object of the present invention is a curing that has no optical blur (chromatic aberration), excellent transparency, and can maintain excellent optical properties and physical properties even when exposed to high temperature conditions such as soldering by a reflow method. An object is to provide a resin and an optical member made of the cured resin.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an epoxy compound having an alicyclic ring can impart heat resistance and transparency to a resin, and further exhibit light bleeding (chromatic aberration). Although known as a compound that can be suppressed, a specific epoxy compound having an ester bond in the molecule among the epoxy compounds having an alicyclic ring is excellent in fluidity, but protons generated from a cationic polymerization initiator The reaction rate with carbonyl oxygen constituting an ester bond forms a relatively stable oxonium ion, so that the curing rate is slow. On the other hand, a specific epoxy compound having no ester bond in the molecule has a fast curing speed but low fluidity. Therefore, by using these in combination within a specific range, the curability is excellent in fluidity, can be cured quickly, and can form a resin excellent in heat resistance and transparency without bleeding of light. It was found that a composition was obtained. The present invention has been completed based on these findings and further research.

That is, the present invention comprises the following component (A) and component (B) as a curable compound at a ratio of the former / the latter (weight ratio) of 5/95 to 50/50. A sex composition is provided.
Component (A): An epoxy compound in which an alicyclic ring and an epoxy group are bonded via a single bond or a linking group and having no ester bond Component (B): an alicyclic ring and an ester Epoxy compound having a bond

The curable compound preferably further contains the following component (C), and particularly contains 5 to 60 parts by weight of component (C) with respect to 100 parts by weight of the sum of components (A) and (B). Is preferred.
Component (C): has an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring (hereinafter sometimes referred to as “alicyclic epoxy group”) and has an ester bond. Not epoxy compounds

In addition, the curable composition of the present invention preferably has an aromatic compound content of less than 5% by weight of the entire curable composition.

The present invention also provides a curable resin obtained by curing the curable composition.

The present invention further provides an optical member made of the cured resin.

The curable composition of the present invention has a low viscosity and high fluidity before being cured, and can be easily poured into a mold or the like, and can form a cured resin quickly by cationic polymerization. Therefore, it is excellent in work efficiency. Moreover, it can be made to harden | cure with the outstanding cure rate exceeding 60% by 140 degreeC and a heat processing for 2 minutes. Therefore, when the cured resin after heat treatment is released and further subjected to heat treatment such as annealing treatment, the effect of curing shrinkage due to the heat treatment can be minimized, and the shape error from the design value is extremely small. Moreover, the occurrence of stress distortion and cracking due to curing shrinkage can be suppressed.

The resulting cured resin has a high Abbe number, so there is no blur of light (chromatic aberration), high optical properties (light transmittance, refractive index, Abbe number, etc.), physical properties (heat resistance, flexibility, water resistance) Etc.), and the optical characteristics and physical characteristics hardly change even under a high temperature condition of about 260 ° C., for example. Such a cured resin is particularly useful for use in an optical member such as a lens because it does not easily turn yellow even when subjected to a soldering process by a reflow method and does not easily change its shape. For example, when the lens made of the cured resin of the present invention is used as a lens for a camera-equipped mobile phone, the camera module can be mounted at the same time in the reflow soldering process (mounting process), which is performed after the soldering process. The connecting step of the camera module with the existing connector can be omitted.

[Curable composition]
The curable composition of this invention is characterized by including the following component (A) and a component (B) as a sclerosing | hardenable compound.
Component (A): An epoxy compound in which an alicyclic ring and an epoxy group are bonded via a single bond or a linking group and having no ester bond Component (B): an alicyclic ring and an ester Epoxy compound having a bond

(Ingredient (A))
Component (A) of the present invention is an epoxy compound in which an alicyclic ring and an epoxy group are bonded via a single bond or a linking group, and has no ester bond (included in the following component (C)) Except for compounds having an alicyclic epoxy group), and a compound that cures by forming a three-dimensional cross-linked structure with other curable compounds by cationic polymerization.

Examples of the alicyclic ring include monocyclic alicyclic rings such as cyclopentane ring, cyclohexane ring, cyclooctane ring, and cyclododecane ring (3 to 15-membered, preferably about 5 to 6-membered cycloalkane ring); decalin ring ( Perhydronaphthalene ring), perhydroindene ring (bicyclo [4.3.0] nonane ring), perhydroanthracene ring, perhydrofluorene ring, perhydrophenanthrene ring, perhydroacenaphthene ring, perhydrophenalene ring, Norbornane ring (bicyclo [2.2.1] heptane ring), isobornane ring, adamantane ring, bicyclo [3.3.0] octane ring, tricyclo [5.2.1.0 ^2,6 ] decane ring, tricyclo [ 6.2.1.0 ^2,7 ] Polycyclic (about 2 to 4 rings) alicyclic ring (bridged carbon ring) such as undecane ring.

Examples of the epoxy compound in which the alicyclic ring and the epoxy group are bonded by a single bond include a compound represented by the following formula (A1).

In the above formula (A1), R ¹ is a group obtained by removing q OH from a q-valent alcohol [R ^1- (OH) _q ], p is an integer of 1 to 30, and q is an integer of 1 to 10. . In the groups in q parentheses, p may be the same or different. As the q-valent alcohol [R ^1- (OH) _q ], monovalent alcohols such as methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol; ethylene glycol, 1,2-propanediol, 1,3 -Divalent alcohols such as propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polypropylene glycol; glycerin, diglycerin, Examples include trihydric or higher alcohols such as erythritol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol. The alcohol may be polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, or the like. [R ¹ — (OH) _q ] in the present invention has a melting point of 60 to 120 ° C., excellent compatibility with other compositions (especially other epoxy compounds), and low temperature (for example, From about -10 to 70 ° C., preferably about 10 to 60 ° C., and can prevent the start of cationic polymerization during the dissolution and kneading. Or higher aliphatic polyhydric alcohol (for example, trimethylolpropane)] is preferable.

Examples of the epoxy compound in which the alicyclic ring and the epoxy group are bonded via a linking group include a glycidyl ether type epoxy compound having an alicyclic ring and a glycidyl ether group. Examples of the glycidyl ether type epoxy compound having an alicyclic ring and a glycidyl ether group include glycidyl ethers of alicyclic alcohols (particularly, alicyclic polyhydric alcohols) represented by the following formulas (A2) to (A5). In the following formula, n1, n2, and n3 each represent an average degree of polymerization, and are, for example, about 0 or more and 10.0 or less.

As the component (A) in the present invention, the above formula is particularly preferable in that a cured resin having excellent optical properties (transparency, low refractive index, etc.) and excellent reactivity, compatibility, and heat resistance can be formed. The compound represented by (A1) is preferable, and in particular, 1,2-epoxy-4- (2-oxiranyl) of 2,2-bis (hydroxymethyl) -1-butanol represented by the following formula (A1-1) ) Cyclohexane adduct is preferred. In the following formulae, p ′, p ″ and p ′ ″ are the same or different and represent an integer of 1 to 30.

(Ingredient (B))
Component (B) of the present invention is an epoxy compound having an alicyclic ring and having an ester bond, and having at least one alicyclic ring in the molecule and having at least one ester bond. Good. Component (B) can form a three-dimensional crosslinked structure with other curable compounds by cationic polymerization to form a cured resin.

The component (B) in the present invention is a liquid having a low viscosity at the temperature at the time of dissolution and kneading with other components (for example, room temperature (25 ° C.), 500 mPa · s or less, more preferably 100 mPa · s or less, particularly preferably Is preferably an epoxy compound having a melting point of −30 ° C. or more and 100 ° C. or less and a molecular weight of 1000 or less (eg, 180 to 900, preferably about 230 to 500). It can be preferably used.

As the component (B) in the present invention, an epoxy compound having an alicyclic epoxy group is excellent in compatibility with other epoxy compounds, has excellent heat resistance and optical properties, and forms a cured resin having appropriate flexibility. In particular, an epoxy compound having two or more (particularly two) alicyclic epoxy groups is preferable.

Examples of the alicyclic ring include the same examples as the alicyclic ring in the component (A). Examples of the alicyclic epoxy group include an epoxycyclopentyl group, a 3,4-epoxycyclohexyl group, and 3,4- And epoxytricyclo [5.2.1.0 ^2,6 ] decane 8- (or 9) yl group (epoxidized dicyclopentadienyl group).

Typical compounds contained in component (B) are shown below. In the following formula (B6), n2 represents an average degree of polymerization, and is, for example, 5 or less (preferably 1 to 2).

In the curable composition according to the present invention, the component (A) and the component (B) are used as the curable compound in the former / the latter (weight ratio) of 5/95 to 50/50 (preferably 5/95 to 40/60). ).

Since the curable composition according to the present invention contains the component (A) and the component (B) as a curable compound in the above range, the composition is low in viscosity and high in fluidity before being cured. It is easy to pour, and can quickly form a cured resin by cationic polymerization. The temperature at which the curable composition starts to cure and the curable composition is heated for 2 minutes to achieve a curing rate of 90%. The difference (reaction temperature gap) from the temperature at which the cured resin can be formed can be reduced (for example, 85 ° C. or less, preferably 60 ° C. or less, particularly preferably 50 ° C. or less). Therefore, the curable composition injected into the mold can be cured and removed from the mold very quickly, and the throughput of the molding equipment (processing capacity per unit time) can be significantly improved. Can do. Moreover, the curable composition concerning this invention can be used suitably for shaping | molding by the casting method. On the other hand, when the component (A) is excessive, the viscosity becomes too high and the injection into a mold or the like tends to be difficult, and when the component (B) is excessive, the curing speed tends to decrease, and the optical There is a tendency for characteristics to deteriorate.

The proportion of the component (A) in the curable composition is, for example, 5 to 50% by weight, preferably 5% by weight or more and 35% by weight of the entire curable composition (or the total amount of the curable compound). %, More preferably 10% by weight or more and less than 35% by weight. When the ratio of a component (A) is less than the said range, since a cure rate will fall and a crosslinking density will fall, there exists a tendency for the heat resistance of the obtained cured resin to fall. On the other hand, when the proportion of the component (A) exceeds the above range, the viscosity tends to be too high and injection into a mold or the like tends to be difficult.

The proportion of the component (B) in the curable composition varies depending on the use of the curable resin, but is, for example, 30 to 95% by weight of the entire curable composition (or the total amount of the curable compound), preferably Is about 35 to 80% by weight, more preferably about 40 to 70% by weight, and most preferably about 56 to 70% by weight. When the ratio of a component (B) is less than the said range, fluidity | liquidity and heat resistance will fall and there exists a tendency for the optical characteristic of the obtained cured resin to fall easily. Moreover, when the ratio of a component (B) exceeds the said range, there exists a tendency for a cure rate to fall and it may be necessary to make hardening temperature higher. Moreover, there exists a tendency for an optical characteristic to fall.

Moreover, the curable compound which concerns on this invention is a point which can provide the more outstanding fluidity | liquidity and the more excellent sclerosis | hardenability, as a curable compound, the following component to the said component (A) and component (B). It is preferable to blend (C).

(Ingredient (C))
The component (C) of the present invention is an epoxy compound having an epoxy group (alicyclic epoxy group) composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring and having no ester bond. Any alicyclic epoxy compound having at least one alicyclic epoxy group and no ester bond may be used. Such a component (C) can form a three-dimensional crosslinked structure with other curable compounds by cationic polymerization to form a cured resin.

Examples of the alicyclic ring include the same examples as the alicyclic ring in the component (A), and examples of the alicyclic epoxy group include the same examples as the alicyclic epoxy group in the component (B). it can.

As the component (C) in the present invention, for example, a compound represented by the following formula (C1) (a compound in which two alicyclic epoxy groups are bonded by a single bond, or bonded through a divalent hydrocarbon group) : Bicycloepoxy compound).

In the above formula, Y ¹ represents a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group, a divalent alicyclic hydrocarbon group, and a group in which a plurality of these are bonded. Examples of the divalent aliphatic hydrocarbon group include linear or branched alkylene groups such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, trimethylene, and tetramethylene groups (for example, C _1-6 alkylene). Group). Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene, 1,3-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1, A divalent cycloalkylene group such as a 4-cyclohexylene group can be exemplified.

Representative compounds included in the compound represented by the formula (C1) are shown below.

Examples of the component (C) include compounds having one alicyclic epoxy group in the molecule in addition to the compound represented by the above formula (C1). The compound may have another epoxy group in addition to the alicyclic epoxy group. Representative compounds are shown below.

The component (C) in the present invention is preferably a bicycloepoxy compound represented by the above formula (C1) in that a cured resin having excellent heat resistance can be formed. In addition to curing the curable composition, it does not shrink during curing, but rather tends to expand in volume, so that the volume shrinkage rate when curing the curable composition can be suppressed and cured. The compound represented by the above formula (C1-1) is preferable in that the distortion and deformation due to the curing shrinkage when the obtained cured resin is annealed can be suppressed.

The proportion of the component (C) in the curable composition varies depending on the use of the curable resin, but is, for example, 65% by weight or less of the entire curable composition (or the total amount of the curable compound), preferably It is about 5 to 60% by weight, particularly preferably about 5 to 35% by weight.

The amount of component (C) added to 100 parts by weight of the sum of components (A) and (B) is, for example, about 5 to 60 parts by weight, preferably 5 to 45 parts by weight, particularly preferably 5 to 25 parts by weight. About a part.

Moreover, as a content rate of a component (A), a component (B), and a component (C), when the total amount of a sclerosing | hardenable compound is 100 weight part, a component (A) / component (B) / component (C) (weight) The ratio is preferably about 5 to 35/55 to 95/0 to 25 (in particular, 10 to 34/56 to 90/5 to 15).

When the component (C) is blended in the above range, excellent fluidity can be imparted to the curable composition while maintaining the transparency of the resulting cured resin. Furthermore, the curing rate is accelerated, and the difference between the temperature at which the curable composition starts to cure and the temperature at which the curable composition can be heated for 2 minutes to form a cured resin having a curing rate of 90% ( The reaction temperature gap) can be reduced to 50 ° C. or less, and the curable composition injected into the mold can be subjected to a curing treatment and taken out from the mold more quickly, which significantly improves the throughput of the molding apparatus. Can be improved.

(Other ingredients)
The curable composition of the present invention may contain other curable compounds (cationic polymerizable compound, radical polymerizable compound, etc.) other than the above components as long as the optical properties and physical properties of the cured resin are not impaired. .

As a blending ratio of the curable compound other than the above components with respect to the total amount of the curable compound in the curable composition of the present invention, the above components (components (A) and (B), preferably the component (A) are used. , (B), (C)) is preferably in a proportion such that it is, for example, 60% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more. Is preferably substantially free (that is, the content of the other curable compound is less than 10% by weight, preferably less than 5% by weight, based on the total amount of the curable compound). If the blending ratio of other curable compounds other than the above components exceeds the above range, it becomes difficult to achieve both fluidity and curing speed, and the optical properties and physical properties of the resulting cured resin tend to deteriorate.

Further, the curable composition of the present invention contains an aromatic compound (for example, bisphenol A type epoxy compound, bisphenol F type epoxy compound, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol type epoxy). Compound, bisphenol type epoxy compound such as 4,4′-biphenol type epoxy compound, bisphenol A novolac type epoxy compound, naphthalenediol type epoxy compound, etc.) content of less than 5% by weight of the whole curable composition (more preferably Less than 1% by weight). When the content of the aromatic compound exceeds the above range, the heat resistance and optical properties (particularly transparency) of the resulting cured resin tend to be reduced. In addition, the minimum of content of an aromatic compound is 0%.

The ratio of the total curable compound to the total amount of the curable composition of the present invention is, for example, 60% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.

The curable composition of the present invention contains various additives such as a cationic polymerization initiator, a curing agent, a curing accelerator, a radical polymerization initiator, and a photosensitizer depending on the type of the curable compound to be used. You may go out.

The cationic polymerization initiator is a compound (curing catalyst, acid generator) that releases a substance that initiates cationic polymerization by heat or light. In the present invention, it is preferable to use a thermal cationic polymerization initiator as the cationic polymerization initiator in that a cured resin having high heat resistance can be rapidly formed. The amount of the cationic polymerization initiator is, for example, 0.01 to 15% by weight, preferably 0.01 to 2% by weight, based on the entire curable composition. By mix | blending in this range, favorable cured resin, such as heat resistance and transparency, can be obtained.

Examples of the cationic polymerization initiator include aryldiazonium salts [for example, trade name “PP-33” (manufactured by Asahi Denka Kogyo Co., Ltd.)], aryliodonium salts, arylsulfonium salts [for example, trade name “FC- 509 ”(manufactured by 3M), trade name“ UVE1014 ”(manufactured by GE Corp.), trade names“ CP-66 ”,“ CP-77 ”(both manufactured by Asahi Denka Kogyo Co., Ltd.) , Trade names "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L", "Sun-Aid SI-110L" (both manufactured by Sanshin Chemical Industry Co., Ltd.), etc.], allene-ion complex [ For example, the trade name “CG-24-61” (manufactured by Ciba Specialty Chemicals) and the like]. Furthermore, a system of a chelate compound of a metal such as aluminum or titanium and an acetoacetate ester or a diketone and a silanol or a phenol is also used. Examples of the chelate compound include aluminum trisacetylacetonate, aluminum trisacetoacetate ethyl and the like. Examples of the silanol or phenols include triphenylsilanol and bisphenol S. In the present invention, among them, the arylsulfonium salt (particularly, trade name “Sun-Aid SI-60L”, trade name “Sun-Aid SI-100L”, etc.) has a temperature at which the curable composition starts to cure, for example, 80 The temperature is lowered to ˜120 ° C. (preferably 80 to 100 ° C.), and the temperature at which the curable composition starts to cure and the temperature at which the cured resin having a curing rate of 90% can be formed by heating for 2 minutes. This is preferable in that the difference (reaction temperature gap) can be reduced and high throughput can be imparted to the molding apparatus.

An acid anhydride can be used as a curing agent. As the acid anhydride, those generally used for curing epoxy compounds can be used, but those which are liquid at room temperature are preferred. Specific examples include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenyl. Mention may be made of succinic anhydride, methylendomethylenetetrahydrophthalic anhydride and the like. In addition, acid anhydrides that are solid at room temperature, for example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, as long as the fluidity of the curable composition of the present invention is not adversely affected. Etc. can be used. When an acid anhydride that is solid at room temperature is used, it is preferably dissolved in a liquid epoxy compound at room temperature and used as a liquid mixture at room temperature. The blending amount of the curing agent varies depending on the kind and amount of the cationic curable compound in the curable composition, but is, for example, less than about 40% by weight, preferably less than about 20% by weight of the entire curable composition. Preferably, it is less than about 10% by weight.

The curing accelerator is a compound having a function of accelerating the curing reaction when an acid anhydride is used as the curing agent. The curing accelerator is not particularly limited as long as it is generally used. For example, a diazabicycloundecene-based curing accelerator (1,8-diazabicyclo [5.4.0] undecene-7 (DBU) or Salt thereof), tertiary amines such as benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, etc. Examples thereof include organic phosphine compounds such as imidazoles and triphenylphosphine, tertiary amine salts, quaternary ammonium salts, phosphonium salts, metal salts such as tin octylate and zinc octylate. Among these, diazabicycloundecene curing accelerators are preferable. The blending amount of the curing accelerator is, for example, about 0 to 5% by weight, preferably about 0.05 to 3% by weight, based on the entire curable composition. If the blending amount is too small, the curing accelerating effect may be insufficient, and if it is too large, the hue of the cured resin may be deteriorated.

As the radical polymerization initiator (radical generator), those known and commonly used as light or thermal radical polymerization initiators can be used. Representative photoradical polymerization initiators include, for example, benzoin / benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino- Acetophenones such as 1- (4-morpholinophenyl) -butan-1-one; anthrax such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-isopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone Xanthones; 1,7-bis (9-acridinyl) heptane and the like.

Typical thermal radical polymerization initiators include, for example, organic peroxides such as diacyl peroxides, peroxydicarbonates, alkyl peresters, dialkyl peroxides, perketals, ketone peroxides, and alkyl hydroperoxides. Is mentioned. Specific examples of these thermal polymerization initiators include dibenzoyl peroxide, t-butyl perbenzoate, azobisisobutyronitrile, and the like.

The blending amount of the radical polymerization initiator varies depending on the kind and amount of the radical polymerizable compound in the curable composition, but is, for example, about 0.1 to 2% by weight of the entire curable composition.

The photosensitizer is preferably used in combination with a radical photopolymerization initiator. As the photosensitizer, known ones can be used. For example, N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethylamine, And tertiary amines such as ethanolamine. These photosensitizers can be used alone or in combination of two or more. The content of the photosensitizer is not particularly limited, but is, for example, about 0.1 to 5% by weight of the entire curable composition.

Other additives may be further added to the curable composition of the present invention. Other additives include, for example, organosiloxane compounds, metal oxide particles, rubber particles, silicone and fluorine antifoaming agents, silane coupling agents, fillers, plasticizers, leveling agents, antistatic agents, release agents. Molding agents, flame retardants, colorants, antioxidants (for example, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenol) propionate] etc. can be used), ultraviolet rays Examples thereof include an absorbent, an ion adsorbent, and a pigment. The amount of these various additives is, for example, 5% by weight or less based on the entire curable composition. The curable composition of the present invention may contain a solvent, but if it is too much, bubbles may occur in the cured resin. For example, it is 10% by weight or less (particularly 1% by weight) of the entire curable composition. Or less).

The curable composition of the present invention includes, for example, the above components (components (A) and (B), preferably components (A), (B) and (C)), a cationic polymerization initiator as necessary, and curing. It is prepared by mixing an agent, a curing accelerator, a radical polymerization initiator, a photosensitizer, various additives, and the like, and stirring and mixing while excluding bubbles under vacuum as necessary. The temperature at the time of stirring and mixing is, for example, about 10 to 60 ° C. For the stirring / mixing, a known apparatus such as a rotation / revolution mixer, a single-screw or multi-screw extruder, a planetary mixer, a kneader, or a dissolver can be used.

The curable composition of the present invention can form a curable resin by cationic polymerization. For example, the curable composition has a desired shape by pouring the curable composition into a mold of a molding apparatus and heating. Can be obtained. The heating temperature can be appropriately adjusted depending on the constitution of the curable composition, and is, for example, 80 to 260 ° C., preferably 90 to 210 ° C., particularly preferably 100 to 150 ° C. In addition, when the liquid temperature of the curable composition before heating is low (for example, room temperature), in order to rapidly increase the liquid temperature, it is previously set at 150 to 250 ° C., preferably 120 to 200 ° C. for 0.1 to 10 minutes. Preferably, after heating for 1 to 5 minutes to increase the liquid temperature of the curable composition, the curing treatment can be performed at the above heating temperature. These curing conditions are appropriately adjusted according to the shape and size of the molding apparatus, the mold, and the cured resin to be obtained.

Moreover, you may irradiate an active energy ray (for example, ultraviolet rays etc.) with heat processing. When ultraviolet rays are used as the active energy rays, the irradiation amount is, for example, about 1000 to 4000 mJ / cm ² .

Further, after the cured resin is taken out of the mold, it is preferable to anneal the cured resin for the purpose of reducing and relaxing the residual stress in the cured resin and for promoting the reaction of unreacted functional groups. . The annealing treatment can be performed by heating at a temperature of 100 to 300 ° C. for about 10 to 300 minutes. For example, a method of heating at a temperature of 130 to 180 ° C. for 10 to 120 minutes, or a temperature of 130 to 180 ° C. Examples thereof include a method of heating at a temperature of 5 to 60 minutes and further heating at a temperature of 230 to 280 ° C. for 1 to 30 seconds. The conditions for the annealing treatment are appropriately adjusted according to the shape and size of the apparatus and the cured resin, and the amount of treatment. By performing the annealing treatment, it is possible to alleviate the distortion of the cured resin to make various physical properties uniform, to prevent the occurrence of cracks, and to further suppress the shape error.

The curable composition of the present invention has a low viscosity [for example, a viscosity at 25 ° C. of 5000 mPa · s or less, preferably 4500 mPa · s or less (for example, 10 to 4500 mPa · s), more preferably 4100 mPa · s or less (for example, 50 to 4100 mPa · s), particularly preferably 4000 mPa · s or less (eg, 50 to 4000 mPa · s), more preferably 2500 mPa · s or less (eg, 150 to 2500 mPa · s), and most preferably 1000 mPa · s or less (eg, 150 to 1000 mPa · s)], it is excellent in fluidity and can be quickly and uniformly injected into a mold or the like without unevenness.

In the present invention, due to the constitution of the curable composition, even at a heating temperature of 140 ° C., 60% or more (preferably 75% or more, preferably by heat treatment for a short time (eg about 5 minutes, preferably 2 minutes or less) Particularly preferably, it can be cured at a curing rate of 90% or more. Therefore, the throughput performance of the molding apparatus can be remarkably improved. In addition, since a cured resin can be obtained with an excellent curing rate by heat treatment at 140 ° C. for 2 minutes, it is then removed from the mold and further subjected to heat treatment (eg, aryl treatment, post-cure, etc.). However, the occurrence of curing shrinkage due to the heat treatment can be suppressed, and the shape error from the design value caused by the curing shrinkage can be kept to a minimum.

In the present specification, the curing rate (%) is defined by the calorific value in the curing process of the curable composition. Specifically, when the curing rate (%) when cured at constant temperature is β, the curing rate is represented by the following formula.
dβ / dt = 1 / H _T (dQ / dt) _T
Here, H _T is the total amount of heat generated during constant temperature measurement, a heating value per unit time at (dQ / dt) _T is a constant temperature measurement. The curing rate is determined by measuring the calorific value of the curable composition by thermal analysis using a differential scanning calorimeter (DSC). The curing rate (%) is obtained by integrating the curing rate with time.

Since the curable resin of the present invention is obtained by curing the curable composition, it has excellent properties in both optical properties and physical properties.

The light transmittance (400 nm) of the cured resin of the present invention is, for example, 80% or more (preferably 86% or more), and the internal transmittance (400 nm) is, for example, 85% or more (preferably 90% or more, particularly preferably 94). %), The refractive index (589 nm) is, for example, 1.45 or more (preferably 1.50 or more), and the Abbe number is, for example, 45 or more (preferably 50 or more, particularly preferably 55 or more). Is preferred.

The glass transition temperature of the curable resin of the present invention is preferably, for example, 80 to 200 ° C. (preferably 120 to 145 ° C.). When the glass transition temperature is lower than 80 ° C., the reflow heat resistance is lowered, and deformation or the like tends to be caused by heating. On the other hand, when the glass transition temperature is higher than 200 ° C., the flexibility of the cured resin is lowered, the brittleness tends to occur, and cracks tend to occur.

Further, the cured resin of the present invention has an elastic modulus at 25 ° C. (measured by a method based on JIS K 7244-1 to 7), for example, about 0.1 to 5 GPa (preferably 0.5 to 3 GPa). The flexural modulus (measured by a method according to JIS K 6911) is, for example, about 0.5 to 10 GPa (preferably 1 to 5 GPa), and has an appropriate flexibility, so that it can be easily removed from a mold or the like. Generation of cracks can be prevented when removing.

Furthermore, the cured resin of the present invention does not substantially change the light transmittance, internal transmittance, refractive index, and Abbe number even when exposed to high temperature conditions (for example, about 260 ° C.) Since the volume shrinkage is 5% or less (preferably 3.5% or less, particularly preferably 3.0% or less), the shape can be maintained.

Furthermore, since the cured resin of the present invention has low hygroscopicity [water absorption is 5% or less (preferably 3% or less, particularly preferably 2% or less)], high-temperature and high-humidity conditions (for example, boiling water) Even when exposed to the extent of immersion, the light transmittance, internal transmittance, refractive index, and Abbe number are not substantially changed, and the shape can be maintained.

The cured resin of the present invention hardly changes in optical characteristics and physical characteristics even at high temperatures. Therefore, for example, even when the cured resin of the present invention is mounted on an optical device and subjected to reflow treatment, changes in various physical property values, particularly optical property values, can be kept to a minimum, and excellent optical properties can be maintained. it can.

The refractive index of the lens varies depending on the wavelength of light, and a phenomenon (chromatic aberration) that causes deviation (bleeding or blurring) in the image occurs. In order to reduce the influence of this chromatic aberration, a normal lens has a structure that corrects chromatic aberration by combining a lens resin having a high Abbe number and a lens resin having a low Abbe number. The glass of a lens used in a camera is classified into two types according to the Abbe number. Generally, those having an Abbe number of 50 or less are called flint glass, and those having 50 or more are called crown glass. The cured resin of the present invention can be suitably used as a high Abbe number lens resin.

The cured resin of the present invention can be suitably used for optical members (for example, optical material applications such as lenses, optical device applications, display device applications, electrical / electronic component material applications, etc.). Examples of the optical member include an imaging lens, a spectacle lens, a filter, a diffraction grating, a prism, a light guide, and a light beam collection for a camera (on-vehicle camera, digital camera, PC camera, mobile phone camera, surveillance camera, etc.). Optical lens, light diffusion lens, cover glass for display device, photo sensor, photo switch, LED, light emitting element, optical waveguide, optical splitter, optical fiber adhesive, display element substrate, color filter substrate, touch panel substrate, Examples thereof include a display protective film, a display backlight, a light guide plate, and an antireflection film.

In particular, when the lens made of the cured resin of the present invention is used as a lens for a camera-equipped mobile phone, the camera module can be mounted at the same time in the soldering process (mounting process) by the reflow method, which is performed after the soldering process. The connection process of the camera module by the existing connector can be omitted, and the workability is excellent.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

The materials used in the examples and comparative examples are as follows.
[Curable compound]
“EHPE3150”: 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol represented by the following formula (wherein p ′ and p ″) P ′ ″ are the same or different and each represents an integer of 1 to 30), trade name “EHPE3150” (manufactured by Daicel Chemical Industries), and a compound represented by the formula (A1).

“YX8000”: a non-ester hydrogenated bisphenol diglycidyl compound represented by the following formula. Product name “YX8000” (Japan Epoxy Resin)

“CEL2021P”: 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate represented by the following formula, trade name “Celoxide 2021P” (manufactured by Daicel Chemical Industries)

“C1-1”: 3,4,3 ′, 4′-diepoxybicyclohexyl represented by the following formula (the compound obtained in Preparation Example 1 below was used)

[Cationic polymerization initiator]
“SI-100L”: Arylsulfonium salt, trade name “Sun-Aid SI-100L” (manufactured by Sanshin Chemical Industry Co., Ltd.)
“SI-60L”: arylsulfonium salt, trade name “Sun-Aid SI-60L” (manufactured by Sanshin Chemical Industry Co., Ltd.)

[Antioxidant]
“IRG1010”: pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenol) propionate], trade name “IRG1010” (manufactured by Ciba Specialty Chemicals)

Preparation Example 1
A dehydration catalyst was prepared by stirring and mixing 70 g (0.68 mol) of 95 wt% sulfuric acid and 55 g (0.36 mol) of 1,8-diazabicyclo [5.4.0] undecene-7 (DBU).
Into a 3 liter flask equipped with a stirrer, a thermometer, and a dehydration pipe and equipped with a heated distillation pipe, 1000 g (5.05 mol) of hydrogenated biphenol (= 4,4′-dihydroxybicyclohexyl), the above 125 g of the dehydration catalyst (0.68 mol as sulfuric acid) and 1500 g of pseudocumene prepared in Step 1 were added, and the flask was heated. The generation of water was confirmed when the internal temperature exceeded 115 ° C. The temperature was further raised to raise the temperature to the boiling point of pseudocumene (internal temperature 162 to 170 ° C.), and dehydration reaction was carried out at normal pressure. By-product water was distilled off and discharged out of the system through a dehydration tube. The dehydration catalyst was liquid under the reaction conditions and was finely dispersed in the reaction solution. After about 3 hours, almost theoretical amount of water (180 g) was distilled, and the reaction was terminated. Pseudocumene was distilled off using a 10-stage Oldershaw type distillation column, and the reaction-terminated liquid was distilled at an internal pressure of 10 Torr (1.33 kPa) and an internal temperature of 137 to 140 ° C. to obtain 731 g of bicyclohexyl-3. , 3'-diene was obtained.

The obtained bicyclohexyl-3,3′-diene (243 g) and ethyl acetate (730 g) were charged into a reactor, and nitrogen was blown into the gas phase portion, and the temperature in the reaction system was controlled to 37.5 ° C. Then, 274 g of a 30 wt% peracetic acid ethyl acetate solution (water content 0.41 wt%) was added dropwise over about 3 hours. After the peracetic acid solution was dropped, the reaction was terminated by aging at 40 ° C. for 1 hour. Further, the crude liquid at the end of the reaction was washed with water at 30 ° C., and the low boiling point compound was removed at 70 ° C./20 mmHg to obtain 270 g of an alicyclic epoxy compound. The oxirane oxygen concentration of the obtained alicyclic epoxy compound was 15.0% by weight. In ¹ H-NMR measurement, a peak derived from an internal double bond in the vicinity of δ4.5 to 5 ppm disappeared, and a proton peak derived from an epoxy group was confirmed in the vicinity of δ3.1 ppm. , 3 ′, 4′-diepoxybicyclohexyl was confirmed.

Examples 1 to 5 and Comparative Examples 1 to 4
Each component described in Table 1 below was blended, and the mixture was stirred and mixed using a rotation and revolution mixer in a normal temperature (25 ° C.) atmosphere to obtain a curable composition.

The curable compositions obtained in Examples and Comparative Examples were evaluated by the following methods.

[viscosity]
The viscosity of the curable composition is an average value of viscosity (mPa · s) measured at 25 ° C. in a shear rate of 15 to 25 s ⁻¹ using a rheometer (trade name “PHYSICA UDS200”, manufactured by Paar Physica). It was used.

[Curing rate]
About the curable composition obtained by the Example and the comparative example, using a differential scanning calorimeter (DSC) (brand name "Q2000", the product made from a TA instrument company), in nitrogen atmosphere, the following A measurement curve was obtained by measuring the amount of heat generated by curing under temperature conditions. Necessary parameters were calculated from the obtained measurement curve, the reaction rate equation of the n-dimensional model was obtained, and the curing rate (%) when heated at 140 ° C. for 2 minutes by the device internal software was calculated.
Temperature conditions: hold at 50 ° C. for 3 minutes, then heat up at 20 ° C./minute, hold at 250 ° C. for 3 minutes, drop in temperature at −20 ° C./minute, hold at −50 ° C. for 3 minutes, then up to 250 ° C. Temperature rise at 20 ° C / min

[Reaction temperature gap]
The curing start temperature (T1) from the measurement curve of the curing calorific value obtained in the above curing rate measurement and the temperature at which a cured resin with a curing rate of 90% can be formed by heating for 2 minutes [curing Temperature (90%, 2 minutes): T2] was calculated, and the difference (T2−T1: ° C.) was taken as the reaction temperature gap.

The above results are summarized in the following table.

The curable compositions obtained in Examples and Comparative Examples were cast at room temperature (25 ° C.) into glass molds that had been surface-treated with a release agent in advance.
Next, the cast curable composition was heated as described below using an oven in an air atmosphere to obtain a cured resin (1).
The curable composition obtained in Example 1: The cast curable composition was heated at 100 ° C. for 60 minutes. The curable composition obtained in Examples 2, 4, 5 and Comparative Example: cast cured The curable composition was rapidly heated from room temperature (25 ° C.) to 140 ° C. at a heating rate of 50 ° C./min and heated at 140 ° C. for 2 minutes. The curable composition obtained in Example 3: Casting curability Heat the composition at 200 ° C. for 5 minutes

Thereafter, the obtained cured resin (1) was once cooled to room temperature (25 ° C.), and further annealed as described below using an oven in an air atmosphere to obtain a cured resin (2). .
Cured resin (1) comprising the curable composition obtained in Examples 1 and 3: Heating at 160 ° C. for 1 hour Cured resin comprising the curable composition obtained in Examples 2, 4, 5 and Comparative Example ( 1): Heated at 160 ° C. for 30 minutes, and further heated at 260 ° C. for 10 seconds using a tabletop reflow oven

The obtained cured resin (2) was evaluated for optical properties, physical properties and heat resistance by the following methods.

[Transmissivity]
With respect to the cured resin (2), the light transmittance (%) at a wavelength of 400 nm was measured by a method based on JIS B 7105 using a spectrophotometer (trade name “U-3900”, manufactured by Hitachi High-Technologies Corporation).

[Internal transmittance]
The internal transmittance of the cured resin (2) was calculated from the following formula.
Internal transmittance (400 nm) = light transmittance at 400 nm / (1-r) ²
r = {(n−1) / (n + 1)} ²
n is the refractive index at 400 nm, and the value of the refractive index at 400 nm measured by the following method was used. Moreover, the value measured by the said method was used for the light transmittance in 400 nm.

[Refractive index]
The refractive index of the cured resin (2) was measured by a method based on JIS K 7142, using a refractometer (trade name “Model 2010”, manufactured by Metricon), and a refractive index of 589 nm at 25 ° C. was measured.

[Abbe number]
The Abbe number of the cured resin (2) was calculated by the following formula.
Abbe number = (n _d −1) / (n _f −n _c )
In the formula, n _d represents a refractive index at 589.2 nm, n _f represents a refractive index at 486.1 nm, and n _c represents a refractive index at 656.3 nm. In addition, as a refractive index, the value measured by the said method was used.

[Glass-transition temperature]
The glass transition temperature of the curable resin (2) was measured using a TMA measuring device (trade name “TMA / SS100”, manufactured by SII NanoTechnology Co., Ltd.) in a nitrogen atmosphere at a rate of temperature increase of 5 ° C./min and a measurement temperature range. The coefficient of thermal expansion was measured at 30 ° C. to 250 ° C., a tangent line was drawn on the curve before and after the glass transition point, and the glass transition temperature (Tg) was obtained from the intersection of the tangent lines.

[Linear expansion coefficient]
The linear expansion coefficient of the cured resin (2) is increased by a method according to JIS K 7197 using a TMA measuring device (trade name “TMA / SS100”, manufactured by SII Nanotechnology), that is, in a nitrogen atmosphere. The coefficient of thermal expansion was measured at a temperature rate of 5 ° C./min and a measurement temperature range of 30 ° C. to 250 ° C., and the slope of the straight line on the low temperature side was expressed as the coefficient of linear expansion.

[Elastic modulus]
The elastic modulus (GPa) of the cured resin (2) is determined by a method according to JIS 7244-1 to 7 using a solid viscoelasticity measuring device (trade name “RSAIII”, manufactured by TA Instruments Inc.), The dynamic viscoelastic properties of a test piece (length 40 mm × width 25 mm × thickness 0.5 mm) were measured in a nitrogen atmosphere at a heating rate of 5 ° C./minute and a measurement temperature range of −30 ° C. to 270 ° C. The elastic modulus at ° C was read.

[Bending elastic modulus]
A test piece (length 25 mm × width 1.0 mm × thickness 1.0 mm) was prepared from the cured resin (2), and a tensile tester (trade name “Tensilon Universal Material Testing Machine RTF-1350”, And Day) was used, and the three-point bending elastic modulus was measured at a bending speed of 1 mm / min according to JIS K 6911.

[Volume shrinkage]
The volume shrinkage (%) of the curable resin (2) was determined by curing the specific gravity (G ₁ ) at 25 ° C. of the curable compositions obtained in Examples and Comparative Examples, and by curing the curable composition by the above method. The specific gravity (G ₂ ) of the obtained cured resin (2) was measured by the following method and calculated from the following formula.
Specific gravity of curable composition (at 25 ° C.): Specific gravity of cured resin (2) measured using a portable electron density meter (trade name “DA-130N”, manufactured by Kyoto Electronics Industry Co., Ltd.): Electronic specific gravity meter (Trade name “SD-200L”, manufactured by Shimadzu Corporation) was used for measurement.
Volume shrinkage (%) = {(G ₂ −G ₁ ) / G ₁ } × 100

[Water absorption rate]
The water absorption of the cured resin (2) was measured by a method based on JIS K7209. That is, after making a test piece (length 10 mm × width 10 mm × thickness 1.0 mm) from the cured resin (2) and pre-drying the obtained test piece with a vacuum dryer (about 50 ° C., 24 hours) The weight (W ₁ ) was measured.
Subsequently, it was immersed in ion-exchanged water, then immersed in boiling ultrapure water for 2 hours, taken out, wiped with Kimwipe, measured for weight (W ₂ ), and water absorption was calculated from the following formula.
Water absorption (%) = {(W ₂ −W ₁ ) / W ₁ } × 100

[Heat resistance test]
A heat resistance test in which the cured resin (2) was previously heated to 270 ° C. and held for 1 minute in an air atmosphere was continuously performed three times to obtain a cured resin (3). With respect to the obtained cured resin (3), the transmittance, internal transmittance, refractive index, and Abbe number are measured by the above method, and the change in transmittance, internal transmittance, refractive index, and Abbe number due to exposure to a high temperature environment. The presence or absence was measured.

The evaluation results are summarized in the following table.

Since the curable composition of the present invention has excellent fluidity, it can be cast easily and quickly, and can be cured very quickly to obtain a cured resin having excellent optical properties, physical properties, and heat resistance. I was able to. On the other hand, the cured resin (2) obtained by curing the curable compositions obtained in Comparative Examples 1 and 2 significantly deteriorated the optical properties when exposed to a high temperature environment, and was not suitable for applications such as lenses. . In addition, the curable composition obtained in Comparative Example 2 had a low viscosity, was easily deformed during casting and after curing had progressed to some extent, and was difficult to handle. On the other hand, since the viscosity of the curable composition obtained in Comparative Example 3 is too high, it is difficult to cast, it is difficult to remove bubbles, and evenly injected into the mold to obtain a cured resin with a smooth surface. I could not. Further, in Comparative Example 4, the curing reaction of the composition proceeded very rapidly, and bubbles were generated inside the cured resin, so that a uniform cured resin could not be obtained.
Therefore, all of the curable compositions of the comparative examples are inferior in moldability, particularly difficult to use for molding by the casting method, or even if the moldability is not bad, from the curable composition, A cured resin excellent in optical properties, physical properties, and heat resistance could not be obtained.

The curable composition of the present invention has high fluidity before being cured, can be easily poured into a mold or the like, is cured extremely rapidly by cationic polymerization, has no light blur, and has heat resistance. A resin having excellent transparency can be formed. In addition, it is possible to suppress the occurrence of stress distortion and cracking due to curing shrinkage. Therefore, the resin obtained by curing the curable composition of the present invention can be suitably used as an optical member that can be soldered by a reflow method.

Claims

A curable composition comprising the following component (A) and component (B) as a curable compound at a ratio of the former / the latter (weight ratio) of 5/95 to 50/50.
Component (A): An epoxy compound in which an alicyclic ring and an epoxy group are bonded via a single bond or a linking group and having no ester bond Component (B): an alicyclic ring and an ester Epoxy compound having a bond
The curable composition according to claim 1, further comprising the following component (C) as a curable compound.
Component (C): an epoxy compound having an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring and having no ester bond
The curable composition according to claim 2, comprising 5 to 60 parts by weight of the component (C) with respect to 100 parts by weight of the sum of the components (A) and (B).
The curable composition according to any one of claims 1 to 3, wherein the content of the aromatic compound is less than 5% by weight of the entire curable composition.
A cured resin obtained by curing the curable composition according to any one of claims 1 to 4.
An optical member made of the cured resin according to claim 5.