WO2011102286A1

WO2011102286A1 - Curable composition and cured material

Info

Publication number: WO2011102286A1
Application number: PCT/JP2011/052828
Authority: WO
Inventors: 久保隆司; 竹中啓起
Original assignee: ダイセル化学工業株式会社
Priority date: 2010-02-16
Filing date: 2011-02-10
Publication date: 2011-08-25
Also published as: JPWO2011102286A1; TW201238977A; CN102762660A; KR20130000390A

Abstract

Disclosed is a curable composition which produces a cured resin resistant to yellowing even under high temperature conditions such as reflow method soldering. The curable composition comprises a cationic polymer compound and at least one organic sulphur compound selected from the group of thiol compounds, dithiol compounds, sulphide compounds and disulphide compounds. It is preferable that the organic sulphur compound has a boiling point of 100°C or above. Additionally, it is preferable that the cationic polymer compound is composed of at least one of the group of epoxy compounds, oxetane compounds and vinyl ether compounds.

Description

Curable composition and cured product

The present invention relates to a curable composition, a cured product thereof, and an optical member. More specifically, a curable composition that can form a cured product that does not easily yellow even at high temperatures, a cured resin that is not easily yellowed by curing the curable composition, and an optical member such as a lens made of the cured resin. About.

¡Deterioration and yellowing of resin materials, especially deterioration due to oxidation, and yellowing are extremely serious problems. The resin material basically undergoes oxidative degradation in the presence of oxygen, and this oxidative degradation is often caused by energy such as ultraviolet rays and heat. In thermoplastic resins such as polyolefin and engineering plastics, various stabilizers are added to prevent deterioration during heating and long-term use of molded products, but as a method to suppress oxidative deterioration of resin materials The use of antioxidants is widely performed. Phenolic antioxidants are typically used, but at the same time, it is necessary to prevent weather resistance, especially UV degradation, and as a stabilizer by selecting additives and combining multiple additives in consideration of these characteristics It has been generally used (Non-Patent Document 1).

On the other hand, in resin compositions that require curing treatment by ultraviolet irradiation in combination with heating, radical polymerization and ionic polymerization (especially cationic polymerization) are carried out in parallel in the curing treatment, and many crosslinks are produced. In order to obtain a cured product having excellent optical properties, the above-mentioned stabilizer rather suppresses the curing reaction, and its addition is not desirable. In addition, the resin composition used for optical materials is often unfavorable in order to bring out the original characteristics obtained from the curable resin composition because the optical characteristics are often impaired by the addition of a stabilizer.

For this reason, attempts have been made to impart an antioxidant function to monomers and the like. Antioxidants include radical scavengers that trap and invalidate the generated radicals, and peroxide decomposers that decompose the generated peroxides into inactive substances and suppress the generation of new radicals. There are types. A hindered phenol compound and a hindered amine compound are used as the former radical scavenger, and a phosphorus compound is mainly used as the latter peroxide decomposer (Patent Document 1).

Since the long-term antioxidant effect is insufficient only with the phenolic antioxidant, the durability of the antioxidant effect is increased by using a phenolic antioxidant and a phosphorus antioxidant together. . However, antioxidants under high temperature conditions (for example, about 260 ° C.) such as soldering by reflow method are not sufficient depending on these antioxidants, and yellowing particularly when used as a material for optical members such as lenses. It was quite insufficient as a suppression. Therefore, for example, most camera-equipped mobile phones are manufactured through a process of connecting a separately manufactured camera module with a connector after a soldering process (mounting process) by a reflow method, and the manufacturing process becomes complicated. ing.

JP-T 2008-52497

An object of the present invention is to provide a curable composition capable of obtaining a curable resin that does not easily turn yellow even under high temperature conditions such as soldering by a reflow method.

Another object of the present invention is to provide a cured resin which is not easily yellowed even under high temperature conditions such as soldering by a reflow method, and an optical member made of the cured resin.

As a result of intensive studies to achieve the above object, the present inventors have found that a curable composition obtained by curing the curable composition according to a curable composition in which a specific organic sulfur compound is blended with a cationic polymerizable compound. For example, even under high temperature conditions of about 260 ° C., the degree of yellowing was found to be extremely small, and the present invention was completed.

That is, the present invention provides a curable composition comprising a cationically polymerizable compound and at least one organic sulfur compound selected from a thiol compound, a dithiol compound, a sulfide compound and a disulfide compound.

As the organic sulfur compound, a compound having a boiling point of 100 ° C. or higher is preferable, and a compound having a boiling point of 150 ° C. or higher is particularly preferable.

The cationic polymerizable compound is preferably at least one compound selected from an epoxy compound, an oxetane compound and a vinyl ether compound.

The curable composition may further contain a radical polymerizable compound. As the radical polymerizable compound, (meth) acrylic acid ester is preferable.

The curable composition may further contain a compound having a cationic polymerizable group and a radical polymerizable group in the molecule.

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.

According to the curable composition of the present invention, it is possible to obtain a cured resin excellent in yellowing resistance that is difficult to yellow even at a high temperature of about 260 ° C., for example. Such a cured resin is not easily yellowed even when it is subjected to a soldering process by a reflow method, and can be used particularly for an optical member such as a lens. For example, when a lens made of a cured resin obtained by curing the curable composition of the present invention is used as a lens for a camera-equipped mobile phone, the camera module can be simultaneously mounted in a soldering process (mounting process) by a reflow method. It becomes possible, and the connection process of the camera module by the connector performed after the soldering process can be omitted.

The curable composition of the present invention contains a cationically polymerizable compound as a curable compound and at least one organic sulfur compound selected from thiol, dithiol, sulfide and disulfide.

[Organic sulfur compounds]
In the present invention, at least one organic sulfur compound selected from thiol compounds, dithiol compounds, sulfide compounds and disulfide compounds is blended in the curable composition. By blending such an organic sulfur compound, yellowing of the cured resin obtained by curing the cured composition at a high temperature can be suppressed.

When a cured product of a curable composition containing a cationically polymerizable compound, particularly a cured product of an epoxy compound or an oxetane compound is placed at a high temperature, radicals are generated in the polymer molecules of the cured resin by the peroxide generated at a high temperature, It is considered that this radical pulls out a hydrogen atom of the polymer molecule to form a conjugated unsaturated bond, and yellowing occurs due to this conjugated unsaturated bond. When an organic sulfur compound such as the above thiol is added to the curable composition, the radical generated by the high radical chain transfer action is captured, and the conjugated unsaturated bond formed and the enethiol reaction are caused to form the unsaturated bond. In order to eliminate, it is estimated that the yellowing of the resin under high temperature can be effectively suppressed. For example, when a thiol compound is used, the thiol compound is converted to a disulfide by radical chain transfer, and this disulfide traps peroxides and singlet oxygen, and the diol compound itself causes an ene-thiol reaction with a conjugated unsaturated bond. It is thought that the unsaturated bond that causes the change disappears.

As an organic sulfur compound, volatilization and foaming do not occur when the monomer composition is crosslinked and cured, and it can be volatilized by heating in a reflow process, which is a short time high-temperature heat treatment while being contained in the cured resin. Those that are difficult to foam are good, for example, those having a boiling point of 100 ° C. or higher, more preferably a boiling point of 150 ° C. or higher, and most preferably those having a boiling point of 180 ° C. or higher. In addition, from the viewpoint of the optical properties and the like of the obtained cured resin, it is preferable to have a high compatibility with the curable compound and obtain a uniform curable composition. In the present specification, the term “boiling point” simply means the boiling point at normal pressure.

Examples of the thiol compound include 1-hexanethiol (boiling point 150 ° C.), 1-heptanethiol (boiling point 177 ° C.), 1-octanethiol (boiling point 200 ° C.), tert-octanethiol (boiling point 156 ° C.), 1-nonane. Thiol, 1-decanethiol (boiling point 241 ° C), 1-undecanethiol (boiling point 104 ° C / 3mmHg), 1-dodecanethiol (boiling point 143 ° C / 16mmHg), 1-tetradecanethiol (boiling point 310 ° C), 1-hexadecanethiol And linear or branched alkanethiol having about 6 to 30 carbon atoms (preferably about 6 to 20 carbon atoms) such as 1-octadecanethiol.

Examples of the dithiol compound include 1,4-butanedithiol (boiling point 195 ° C.), 2,3-butanedithiol (boiling point 87 ° C./50 mmHg), 1,5-pentanedithiol (108 ° C./15 mmHg) 1,6-hexane. Dithiol (boiling point 237 ° C), 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol (boiling point 297 ° C), 1,12-dodecanedithiol, 1,14 -Linear or branched alkanedithiol having about 4 to 30 carbon atoms (preferably about 4 to 20 carbon atoms) such as tetradecanedithiol, 1,16-hexadecanedithiol, 1,18-octadecanedithiol, etc. .

As sulfide compounds, dihexyl sulfide (boiling point 260 ° C.), diheptyl sulfide (boiling point 298 ° C.), dioctyl sulfide (boiling point 309 ° C.), didecyl sulfide (boiling point 217 ° C./8 mmHg), didodecyl sulfide, ditetradecyl sulfide, Linear or branched dialkyl sulfide (alkyl sulfide) having about 6 to 40 carbon atoms (preferably about 10 to 40 carbon atoms) such as dihexadecyl sulfide and dioctadecyl sulfide; diphenyl sulfide (boiling point 296 ° C.), Aromatic sulfides having about 12 to 30 carbon atoms such as phenyl-p-tolyl sulfide (boiling point 312 ° C.) and 4,4-thiobisbenzenethiol (boiling point 148 ° C./12 mmHg); 3,3′-thiodipropionic acid ( Boiling point 409 ° C), 4,4'-thio Such as thiodicarboxylic acids such as butanoic acid, and the like. Among these, dialkyl sulfide is preferable.

Examples of the disulfide compound include dipropyl disulfide (boiling point 193 ° C.), diisopropyl disulfide (boiling point 177 ° C.), dibutyl disulfide (boiling point 226 ° C.), diisobutyl disulfide (109 ° C./13 mmHg), di-tert-butyl disulfide (boiling point 142). ° C / 17 mmHg), dihexyl disulfide (boiling point 229 ° C), diheptyl disulfide, dioctyl disulfide, didecyl disulfide (boiling point 208 ° C / 2 mmHg), didodecyl disulfide, ditetradecyl disulfide, dihexadecyl disulfide, dioctadecyl disulfide, etc. Examples thereof include linear or branched dialkyl disulfides having about 4 to 40 carbon atoms (preferably about 6 to 40 carbon atoms).

Among these organic sulfur compounds, thiol compounds, dithiol compounds, and disulfide compounds are preferable from the viewpoint of yellowing suppression effect, and thiol compounds and disulfide compounds are particularly preferable.

The amount of the organic sulfur compound used can be used within a range that does not impair the curability of the curable compound, and varies depending on the type of the organic sulfur compound. For example, the total amount of the curable compound (or the total amount of the curable composition) On the other hand, it is 0.05 to 10% by weight, preferably 0.1 to 5% by weight, more preferably about 0.2 to 3% by weight. If the amount of the organic sulfur compound is too large, the curability of the curable compound may be impaired. When there is too little quantity of an organic sulfur compound, the yellowing suppression effect of cured resin will become small.

[Cationically polymerizable compound (cationic curable compound) (A)]
The curable composition of the present invention contains a cationically polymerizable compound (A). When a composition containing a cationically polymerizable compound is cured, a cured resin having low curing shrinkage and low hygroscopicity is generally obtained. The cationic polymerizable compound (A) is not particularly limited as long as it is a compound capable of cationic polymerization, but an epoxy compound, an oxetane compound, a vinyl ether compound and the like are preferable in terms of curability, physical properties of the cured resin, optical properties, and the like. . A cationically polymerizable compound (A) can be used individually or in combination of 2 or more types. As the cationically polymerizable compound (A), it is particularly preferable to use at least an epoxy compound and / or an oxetane compound, particularly at least an epoxy compound.

[Epoxy compound]
The epoxy compound includes an epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule, and an epoxy compound having an alicyclic ring (aliphatic carbocycle) and an epoxy group in the molecule (however, it does not have an aromatic ring) (A2 ) And an epoxy compound (A3) having no aromatic ring and alicyclic ring in the molecule. The epoxy compound may be a monofunctional epoxy compound having only one epoxy group in the molecule, or may be a polyfunctional epoxy compound having two or more epoxy groups in the molecule. It is preferable to use at least a polyfunctional epoxy compound as the epoxy compound. An epoxy compound can be used individually or in combination of 2 or more types.

In the epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule, examples of the aromatic ring include a benzene ring, a biphenyl ring, a naphthalene ring, a fluorene ring, an anthracene ring, a stilbene ring, a dibenzothiophene ring, and a carbazole ring. Can be mentioned. The aromatic ring is preferably one containing at least an aromatic carbocyclic ring.

As a typical example of the epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule, for example, an epi obtained by a condensation reaction of bisphenols such as bisphenol A, bisphenol F, bisphenol S, and fluorene bisphenol with an epihalohydrin. Bis type glycidyl ether type epoxy resin; high molecular weight epibis type glycidyl obtained by further adding these epibis type glycidyl ether type epoxy resins with bisphenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, etc. Ether type epoxy resins; phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, bisphenol S and the like Novolac alkyl type glycidyl ether type epoxy resin obtained by condensation reaction of polyhydric phenols obtained by condensation reaction of aldehydes such as mualdehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, salicylaldehyde, etc. with epihalohydrin; fluorene ring An epoxy compound in which two phenol skeletons are bonded to the 9-position of the glycidyl group and a glycidyl group is bonded to a hydroxyl group of the two phenol skeletons directly or via an alkyleneoxy group [an epoxy having a bisarylfluorene skeleton Compound] and the like.

Preferred examples of the epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule include compounds represented by the following formulas (A1-1), (A1-2), and (A1-3).

In the above formulas, R ¹ and R ² are the same or different and each represents an alkylene group, the ring Z ¹ and ring Z ² are the same or different and represent an aromatic carbocycle, and k1 and k2 are the same or different. 0 or an integer of 1 or more, and m1 and m2 are the same or different and represent an integer of 0 or 1 or more. However, m1 + m2 is 1 or more. In the formula (A1-3), the fluorene ring, ring Z ¹ , and ring Z ² may have a substituent.

Examples of the alkylene group in R ¹ and R ² include linear or branched alkylene groups having 1 to 10 carbon atoms such as methylene, ethylene, propylene, trimethylene, tetramethylene and hexamethylene groups. Preferred alkylene groups include alkylene groups having 2 to 6 carbon atoms (particularly alkylene groups having 2 to 3 carbon atoms) such as ethylene, propylene and trimethylene groups.

Examples of the aromatic carbocycle in the ring Z ¹ and the ring Z ² include about 1 to 4 aromatic carbocycles such as a benzene ring, a naphthalene ring, and an anthracene ring. Preferred aromatic carbocycles include benzene rings, naphthalene rings and the like.

K1 and k2 are each 0 or an integer of 1 or more, preferably 0 or an integer of 1 to 10, more preferably 0 or an integer of 1 to 4. m1 and m2 are each 0 or an integer of 1 or more, preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

In the formula (A1-3), examples of the substituent that the fluorene ring, ring Z ¹ , and ring Z ² may have include alkyl groups such as methyl, ethyl, propyl, and isopropyl groups (for example, C _{1- 6} alkyl groups, preferably methyl groups); cycloalkyl groups such as cyclopentyl and cyclohexyl groups (for example, C _5-8 cycloalkyl groups); aryl groups such as phenyl and naphthyl groups (for example, C _6-15 aryl groups); Aralkyl groups such as benzyl groups (eg C _7-16 aralkyl groups); Acyl groups such as acetyl, propionyl and benzoyl groups (eg C _1-10 acyl groups); methoxy, ethoxy, propyloxy, isopropyloxy groups, etc. Alkoxy groups (eg, C _1-6 alkoxy groups); alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups (eg, C _1-4 alkoxy groups) -Carbonyl group); cyano group; carboxyl group; nitro group; amino group; substituted amino group (eg, di-C _1-4 alkylamino group); halogen atom such as fluorine atom and chlorine atom.

As an epoxy compound having an alicyclic ring and an epoxy group in the molecule (but not having an aromatic ring) (A2), an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring ( An alicyclic epoxy compound having an alicyclic epoxy group); an epoxy compound in which an epoxy group is directly bonded to the alicyclic ring by a single bond; a glycidyl ether type epoxy compound having an alicyclic ring and a glycidyl ether group. 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); Hydronaphthalene 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 alicyclic epoxy group include an epoxycyclopentyl group, a 3,4-epoxycyclohexyl group, and a 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane 8- (or 9) yl. Group (epoxidized dicyclopentadienyl group) and the like.

As the alicyclic epoxy compound having the alicyclic epoxy group, a compound represented by the following formula (A2-1) (a compound in which two alicyclic epoxy groups are bonded by a single bond or via a linking group) Can be mentioned.

In the above formula, Y ¹ represents a single bond or a linking group. Examples of the linking group include a divalent hydrocarbon group, a carbonyl group (—CO—), an ether bond (—O—), an ester bond (—COO—), an amide bond (—CONH—), a carbonate bond (— OCOO-) and a group in which a plurality of these are bonded. Examples of the divalent hydrocarbon group include linear or branched alkylene groups such as methylene, ethylidene, isopropylidene, ethylene, propylene, trimethylene, and tetramethylene groups (for example, C _1-6 alkylene groups); Divalent groups such as 2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylidene groups And alicyclic hydrocarbon groups (particularly divalent cycloalkylene groups); groups in which a plurality of these are bonded.

Typical compounds included in the compound represented by the formula (A2-1) are shown below.

In the above formula, n is an integer from 1 to 30.

In addition, as the alicyclic epoxy compound, there are two adjacent carbon atoms and oxygen having an alicyclic ring and two or more epoxy groups in the molecule, and only one of the two or more epoxy groups forms the alicyclic ring. The compound which is an epoxy group (alicyclic epoxy group) comprised with an atom is mentioned. This representative compound (limonene diepoxide) is shown below.

Moreover, as an alicyclic epoxy compound, the alicyclic epoxy compound which has the following 3 or more alicyclic epoxy groups, and an alicyclic which has only one alicyclic epoxy group and does not have an epoxy group in others A formula epoxy compound can also be used.

In the above formula, a, b, c, d, e, and f are integers from 0 to 30.

Examples of the epoxy compound in which an epoxy group is directly bonded to the alicyclic ring with a single bond include a compound represented by the following formula (A2-2).

In the above formula, R ³ is a group obtained by removing q OH from a q-valent alcohol [R ³ — (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 ^3- (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, and sorbitol. The alcohol may be polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, or the like. The alcohol is preferably an aliphatic alcohol having 1 to 10 carbon atoms (particularly an aliphatic polyhydric alcohol such as trimethylolpropane).

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). This compound may be a compound in which the aromatic ring of the epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule is nuclear hydrogenated. Examples of the glycidyl ether type epoxy compound having an alicyclic ring and a glycidyl ether group include the following compounds.

Examples of the epoxy compound (A3) having no aromatic ring or alicyclic ring in the molecule include glycidyl ether of the above q-valent alcohol [R ³ — (OH) _q ]; acetic acid, propionic acid, butyric acid, stearic acid, Glycidyl esters of mono- or polyvalent carboxylic acids such as adipic acid, sebacic acid, maleic acid, itaconic acid; epoxidized oils and fats having double bonds such as epoxidized linseed oil, epoxidized soybean oil, epoxidized castor oil; epoxy And epoxidized products of polyolefins (including polyalkadienes) such as modified polybutadiene.

[Oxetane compounds]
The oxetane compound may be either a monofunctional oxetane compound or a polyfunctional oxetane compound, and a known oxetane compound can be used. Oxetane compounds can be used alone or in combination of two or more.

Examples of oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, di [1-ethyl -(3-Oxetanyl)] methyl ether, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl } Benzene, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, oxetanyl-silsesquioxane, phenol novolac oxetane and the like.

[Vinyl ether compounds]
The vinyl ether compound may be either a monofunctional vinyl ether compound or a polyfunctional vinyl ether compound, and a known vinyl ether compound can be used. A vinyl ether compound can be used individually or in combination of 2 or more types.

Examples of vinyl ether compounds include aryl vinyl ethers such as phenyl vinyl ether; alkyl vinyl ethers such as n-butyl vinyl ether and n-octyl vinyl ether; cycloalkyl vinyl ethers such as cyclohexyl vinyl ether; 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxybutyl Vinyl ether having a hydroxyl group such as vinyl ether; polyfunctionality such as hydroquinone divinyl ether, 1,4-butanediol divinyl ether, cyclohexane divinyl ether, cyclohexane dimethanol divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether Vinyl ether And the like.

As the cationic polymerizable compound (A), in addition to the above, a compound having a different cationic polymerizable group in the molecule can also be used. For example, as a compound having an epoxy group (for example, an alicyclic epoxy group) and a vinyl ether group in the molecule, a compound described in JP2009-242242A can be used. Further, as a compound having an oxetane group and a vinyl ether group in the molecule, compounds described in JP-A-2008-266308 can be used.

The proportion of the cationically polymerizable compound (A) in the curable composition of the present invention varies depending on the use of the cured resin, etc., but with respect to the entire curable composition (or the total amount of the curable compound), for example, It is about 5 to 100% by weight, preferably about 10 to 90% by weight, and more preferably about 15 to 80% by weight.

[Other curable compounds]
The curable composition of this invention may contain the radically polymerizable compound (radical curable compound) (B) with the said cationically polymerizable compound (A). A radically polymerizable compound (B) can be used individually or in combination of 2 or more types. In addition, a cation having a cationic polymerizable group and a radical polymerizable group and a radical polymerizable compound (C) may be included in the molecule. A cation and a radically polymerizable compound (C) can be used individually or in combination of 2 or more types.

The cured product obtained from the dual curable composition in which the cationic polymerizable compound (A) and the radical polymerizable compound (B) are combined has a molecular chain as compared with the cured product of only the cationic polymerizable compound (A). Since the network structure is formed, the strength of the cured product is high and the solvent resistance is also improved. Moreover, compared with the hardened | cured material only of a radically polymerizable compound (B), generally there exists an advantage that cure shrinkage is small and a hygroscopic property is also low. Further, a ternary system in which a cation having a cationic polymerizable group and a radical polymerizable group in the molecule and a radical polymerizable compound (C) are further added to the cationic polymerizable compound (A) and the radical polymerizable compound (B). In the curable composition, a compound having a cationically polymerizable group and a radically polymerizable group in the molecule acts as a crosslinking agent between the cationically cured resin and the radically cured resin, and has physical properties such as heat resistance and optical properties. Can greatly improve.

[Radically polymerizable compound (radical curable compound) (B)]
The radical polymerizable compound (B) is not particularly limited as long as it is a radical polymerizable compound. For example, a compound having a (meth) acryloyl group [(meth) acrylic acid ester, (meth) acrylic acid amide, etc.], Styrenic compounds, olefins, and the like can be used, but compounds having a (meth) acryloyl group, in particular (meth) acrylic acid esters, are preferred from the viewpoints of polymerizability and physical properties of the cured resin. By using a radically polymerizable compound, the heat resistance of the cured resin can be improved.

Of the (meth) acrylic acid esters, acrylic acid esters are more preferable. When the radical polymerization rates of the monomer having an acryloyloxy group and the monomer having a methacryloyloxy group are compared, the former is slower. On the other hand, when comparing the reaction rate of radical polymerization with the reaction rate of cationic polymerization, radical polymerization is generally faster. In a system in which radical polymerization and cationic polymerization proceed in parallel as in the present invention, it is preferable that radical polymerization and cationic polymerization proceed as evenly as possible from the viewpoint of physical properties of the cured resin. If radical polymerization proceeds first, the cure shrinkage of the resulting cured resin increases, and many unreacted cationic polymerizable groups remain even after completion of radical polymerization. Reaction and decomposition may occur, and physical properties of the cured resin may be impaired. For this reason, acrylic acid ester is more preferable among (meth) acrylic acid ester.

(Meth) acrylic acid ester has (meth) acrylic acid ester (B1) having an aromatic ring and (meth) acryloyloxy group in the molecule, and has an alicyclic ring and (meth) acryloyloxy group in the molecule (meth) There are acrylic acid esters (but not having an aromatic ring) (B2), and (meth) acrylic acid esters (B3) having no aromatic ring and alicyclic ring in the molecule. The (meth) acrylic acid ester may be a monofunctional (meth) acrylate having only one (meth) acryloyloxy group, or a polyfunctional (meth) acrylate having two or more (meth) acryloyloxy groups. Also good. As the (meth) acrylic acid ester, it is preferable to use at least a polyfunctional (meth) acrylate. These (meth) acrylic acid esters can be used alone or in combination of two or more.

In the (meth) acrylic acid ester (B1) having an aromatic ring and a (meth) acryloyloxy group in the molecule, examples of the aromatic ring include a benzene ring, a biphenyl ring, a naphthalene ring, a fluorene ring, an anthracene ring, a stilbene ring, Examples thereof include a dibenzothiophene ring and a carbazole ring. The aromatic ring is preferably one containing at least an aromatic carbocyclic ring. Further, as the (meth) acrylic acid ester (B1) having an aromatic ring and a (meth) acryloyloxy group in the molecule, a compound having a conjugated structure composed of 7 or more carbon atoms is preferable. According to such a compound, a cured resin having a high refractive index can be obtained by curing.

In the above (B1), the aromatic ring and the (meth) acryloyloxy group may be directly bonded or may be bonded via a linking group. Examples of the linking group include those similar to the linking group for Y ¹ in formula (A2-1).

Representative examples of (B1) include, for example, (meth) acrylic acid esters of bisphenols such as bisphenol A, bisphenol F, bisphenol S, and fluorene bisphenol; ethylene oxide and / or propylene oxide adducts of the bisphenols (Meth) acrylic acid ester; two phenol skeletons are bonded to the 9-position of the fluorene ring, and (meth) acryloyloxy groups are bonded to the hydroxyl groups of the two phenol skeletons directly or via an alkyleneoxy group, respectively. (Meth) acrylic acid ester [(meth) acrylic acid ester having a bisarylfluorene skeleton]; (meth) acryloyloxy group is bonded to two hydroxyl groups of biphenol either directly or through an alkyleneoxy group, respectively. Etc. and are (meth) acrylic acid esters.

Preferred examples of the (meth) acrylic acid ester (B1) having an aromatic ring and a (meth) acryloyloxy group in the molecule include compounds represented by the following formulas (B1-1) and (B1-2).

In the above formula, R ⁴ and R ⁵ are the same or different and represent a hydrogen atom or a methyl group, R ⁶ and R ⁷ are the same or different and represent an alkylene group, and ring Z ³ and ring Z ⁴ are It is the same or different and represents an aromatic carbocycle, r1 and r2 are the same or different and represent 0 or an integer of 1 or more, and s1 and s2 are the same or different and represent 0 or an integer of 1 or more. However, s1 + s2 is 1 or more. In the formula (B1-1), the fluorene ring, ring Z ³ , and ring Z ⁴ may have a substituent.

Examples of the alkylene group in R ⁶ and R ⁷ include linear or branched alkylene groups having 1 to 10 carbon atoms such as methylene, ethylene, propylene, trimethylene, tetramethylene and hexamethylene groups. Preferred alkylene groups include alkylene groups having 2 to 6 carbon atoms (particularly alkylene groups having 2 to 3 carbon atoms) such as ethylene, propylene and trimethylene groups.

Examples of the aromatic carbocycle in the ring Z ³ and the ring Z ⁴ include about 1 to 4 aromatic carbocycles such as a benzene ring, a naphthalene ring, and an anthracene ring. Preferred aromatic carbocycles include benzene rings, naphthalene rings and the like.

R1 and r2 are each 0 or an integer of 1 or more, preferably 0 or an integer of 1 to 10, more preferably 0 or an integer of 1 to 4. Each of s1 and s2 is 0 or an integer of 1 or more, preferably 1 to 4, more preferably 1 or 2, and particularly preferably 1.

In the formula (B1-1), examples of the substituent that the fluorene ring, ring Z ³ , and ring Z ⁴ may have include alkyl groups such as methyl, ethyl, propyl, and isopropyl groups (for example, C _{1- 6} alkyl groups, preferably methyl groups); cycloalkyl groups such as cyclopentyl and cyclohexyl groups (for example, C _5-8 cycloalkyl groups); aryl groups such as phenyl and naphthyl groups (for example, C _6-15 aryl groups); Aralkyl groups such as benzyl groups (eg C _7-16 aralkyl groups); Acyl groups such as acetyl, propionyl and benzoyl groups (eg C _1-10 acyl groups); methoxy, ethoxy, propyloxy, isopropyloxy groups, etc. Alkoxy groups (eg, C _1-6 alkoxy groups); alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups (eg, C _1-4 alkoxy groups) -Carbonyl group); cyano group; carboxyl group; nitro group; amino group; substituted amino group (eg, di-C _1-4 alkylamino group); halogen atom such as fluorine atom and chlorine atom.

As the (B1), in addition to the above, monofunctional (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate can also be used.

In the (meth) acrylic acid ester having an alicyclic ring and a (meth) acryloyloxy group in the molecule (but not having an aromatic ring) (B2), the alicyclic ring may be a cyclopentane ring, a cyclohexane ring or a cyclooctane ring. Monocyclic alicyclic rings such as cyclododecane ring; decalin ring (perhydronaphthalene ring), perhydroindene ring (bicyclo [4.3.0] nonane ring), perhydroanthracene ring, perhydrofluorene ring, perhydro Phenanthrene 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, polycyclo [6.2.1.0 ^2,7 ] undecane ring, and other polycyclic alicyclic rings (Bridged carbocycle). As the alicyclic ring, a polycyclic alicyclic ring (bridged carbocyclic ring) is preferable. When (meth) acrylic acid ester having a polycyclic alicyclic ring (bridged carbon ring) such as tricyclo [5.2.1.0 ^2,6 ] decane ring in the molecule is used, the heat resistance of the cured resin is improved. In addition, the moisture absorption rate, thermal elastic modulus, and linear expansion coefficient can be reduced. Moreover, melt viscosity and a dielectric constant can be reduced, and a softening point, mechanical strength, and adhesiveness can be improved.

As the (meth) acrylic acid ester (but not having an aromatic ring) (B2) having an alicyclic ring and a (meth) acryloyloxy group in the molecule, for example, a compound represented by the following formula (B2-1): Can be mentioned.

In the above formula, ring Z ⁵ represents an alicyclic ring, and Y ² and Y ³ are the same or different and represent a single bond or a linking group. Examples of the alicyclic ring in ring Z ⁵ include the alicyclic rings exemplified above. The ring Z ⁵ is preferably a polycyclic alicyclic ring such as a tricyclo [5.2.1.0 ^2,6 ] decane ring.

Examples of the linking group in Y ² and Y ³ include a divalent hydrocarbon group, a carbonyl group (—CO—), an ether bond (—O—), an ester bond (—COO—), an amide bond (—CONH—). ), A carbonate bond (—OCOO—), a group in which a plurality of these are bonded, and the like. Examples of the divalent hydrocarbon group include linear or branched alkylene groups such as methylene, ethylidene, isopropylidene, ethylene, propylene, trimethylene and tetramethylene groups (for example, C _1-10 alkylene groups, preferably C _1-6 alkylene group); 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene And a divalent alicyclic hydrocarbon group (particularly a divalent cycloalkylene group) such as a cyclohexylidene group; and a group in which a plurality of these are bonded. As the linking group for Y ² and Y ³ , in particular, a divalent hydrocarbon group (particularly an alkylene group), or one or two or more divalent hydrocarbon groups (particularly an alkylene group) and one or two or more A group to which an oxygen atom (—O—) is bonded is preferable.

Representative examples of the compound represented by the formula (B2-1) include 1,4-cyclohexanediol di (meth) acrylate, 1,4-cyclohexanedimethanol di (meth) acrylate, bicyclo [2.2.1 ] Heptane dimethanol di (meth) acrylate, 1,3-adamantanediol di (meth) acrylate, 1,3-adamantane dimethanol di (meth) acrylate, tricyclo [5.2.1.0 ^2,6 ] decandi Examples include methanol di (meth) acrylate.

(Meth) acrylic acid ester having an alicyclic ring and a (meth) acryloyloxy group in the molecule (but not having an aromatic ring) (B2) includes cyclohexyl (meth) acrylate, cyclohexanemethanol (meth) acrylate, 1- Adamantanol (meth) acrylate, 1-adamantane methanol (meth) acrylate, isobornyl (meth) acrylate, tricyclo [5.2.1.0 ^2,6 ] decane methanol (meth) acrylate [= dicyclopentanyl (meth) Acrylate] and monofunctional (meth) acrylates such as dicyclopentanyloxyethyl (meth) acrylate can also be used.

Examples of the (meth) acrylic acid ester (B3) having no aromatic ring or alicyclic ring in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) Monofunctional (meth) acrylates such as acrylate, nonyl (meth) acrylate, decyl (meth) acrylate; ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di ( (Meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, tri (meth) acrylate of glycerin ethylene oxide adduct, trimethylolpropane tri (meta) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polyfunctional (meth) acrylates such as dipentaerythritol poly (meth) acrylate.

The ratio of the radically polymerizable compound (B) in the curable composition of the present invention varies depending on the use of the curable resin, but is 0 for the entire curable composition (or the total amount of the curable compound), for example. It is about 90 to 90% by weight, preferably about 10 to 90% by weight, and more preferably about 15 to 80% by weight.

[Cation and radical polymerizable compound (C)]
The cation and radical polymerizable compound (C) are not particularly limited as long as the compound has a cation polymerizable group and a radical polymerizable group in the molecule, and various compounds can be used. These compounds can be used alone or in combination of two or more. When such a cation and radical polymerizable compound (C) are blended in a cured composition together with, for example, the cation polymerizable compound (A) and the radical polymerizable compound (B), the cation and radical polymerizable compound (C) However, it often acts as a cross-linking agent between a cationic curable resin and a radical curable resin, and physical properties such as heat resistance and optical properties are often greatly improved.

As the cation and radical polymerizable compound (C), in the molecule, at least one cation polymerizable group selected from an epoxy group, an oxetane group and a vinyl ether group (particularly an epoxy group, particularly an alicyclic epoxy group), and at least A compound having one (meth) acryloyl group [particularly, a (meth) acryloyloxy group] is preferable. Examples of the alicyclic epoxy group include an epoxycyclopentyl group, a 3,4-epoxycyclohexyl group, and 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] represented by the following formula (a). Examples include decane 8- (or 9) yl group.

As the cation and radical polymerizable compound (C), an alicyclic epoxy group [particularly, 3,4-epoxytricyclo [5.2.1.0] decane 8- ( Or 9) a compound having an yl group] can significantly improve the heat resistance of the cured resin and reduce the moisture absorption rate, the elastic modulus during heat, and the linear expansion coefficient. Moreover, melt viscosity and a dielectric constant can be reduced, and a softening point, mechanical strength, and adhesiveness can be improved.

Moreover, as a cation and a radically polymerizable compound (C), the reason similar to the case of the (meth) acrylic acid ester in the said radically polymerizable compound (radical curable compound) (B) (a radical polymerization and cationic polymerization can be performed as much as possible. And at least one cationically polymerizable group (especially an epoxy group) selected from an epoxy group, an oxetane group and a vinyl ether group, and at least one acryloyl group [especially acryloyloxy] Compounds having a group] are preferred.

As the cation and radical polymerizable compound (C), a compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule is particularly preferable, and an epoxy group and an acryloyloxy group are particularly preferable in the molecule. Compounds are preferred.

Examples of the compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule include (i) (meth) acrylic acid ester having an alicyclic epoxy group, and (ii) (meth) acrylic having a glycidyl group. Examples include acid esters. The alicyclic epoxy group is not particularly limited as long as it is an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring. Examples of the alicyclic ring include monocyclic alicyclic rings such as cyclopentane ring, cyclohexane ring, cyclooctane ring and cyclododecane ring (3 to 15 member, 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 alicyclic epoxy group include an epoxycyclopentyl group, a 3,4-epoxycyclohexyl group, and 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane represented by the above formula (a). An 8- (or 9) yl group and the like can be mentioned. The alicyclic epoxy group includes a bridged carbocyclic ring such as a 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decane 8- (or 9) yl group represented by the formula (a). And an alicyclic epoxy group composed of an epoxy group composed of two adjacent carbon atoms and an oxygen atom constituting the bridged carbon ring.

As typical examples of the compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule, compounds represented by the following formulas (C1-1) and (C1-2) may be mentioned.

In the above formula, R ¹⁰ represents a hydrogen atom or a methyl group, Y ⁴ represents a single bond, an alkylene group having 1 to 10 carbon atoms, or an alkylene group having 1 to 2 or more carbon atoms and 1 or 2 or more. And an oxygen atom (—O—) bonded to each other, and ring Z ⁶ represents an alicyclic epoxy group. Examples of the alkylene group having 1 to 10 carbon atoms include linear or branched alkylene groups such as methylene, ethylene, propylene, trimethylene, tetramethylene and hexamethylene groups.

As Y ⁴ , in particular, a single bond, an alkylene group having 1 to 6 carbon atoms, an alkyleneoxy group having 1 to 6 carbon atoms (the oxygen atom is at the right end), and a plurality of alkyleneoxy groups having 1 to 6 carbon atoms (for example, It is preferably a bonded polyalkyleneoxy group (terminal oxygen atom is at the right end).

The following compounds can be given as more specific examples of the compound represented by the formula (C1-1).

In the above formula, R ¹⁰ and Y ⁴ are the same as described above.

Specific examples of the compound represented by the formula (C1-2) include glycidyl (meth) acrylate.

The proportion of the cation and the radical polymerizable compound (C) in the curable composition of the present invention is, for example, 0 to 70% by weight, preferably with respect to the entire curable composition (or the total amount of the curable compound). Is about 5 to 50% by weight, more preferably about 8 to 40% by weight.

[Combination of Cationic Polymerizable Compound (A), Radical Polymerizable Compound, (B), and Cation and Radical Polymerizable Compound (C)]
In the curable composition of the present invention, the combination of the cationic polymerizable compound (A), the radical polymerizable compound, (B), the cation and the radical polymerizable compound (C) can be appropriately selected depending on the use of the cured resin.

When using cured resin for optical applications such as lenses, optical properties (light transmittance, refractive index, Abbe number, etc.) and physical properties [heat resistance (high glass transition point), moisture absorption, linear expansion coefficient, The following combinations (i) and (ii) are preferable from the viewpoint of improving curing shrinkage and the like].
(I) Epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule, (meth) acrylic acid ester (B1) having an aromatic ring and a (meth) acryloyloxy group in the molecule, and an epoxy group in the molecule And a compound (C1) having a (meth) acryloyloxy group (ii) An epoxy compound having an alicyclic ring and an epoxy group in the molecule (however, having no aromatic ring) (A2), A (meth) acrylic acid ester having a ring and a (meth) acryloyloxy group (but not having an aromatic ring) (B2), and a compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule; Combination

In the combination (i), the epoxy compound (A1) having an aromatic ring and an epoxy group in the molecule is preferably a polyfunctional epoxy compound, and in particular, the formula (A1-1), the formula (A1-2), A compound represented by the formula (A1-3) [in particular, a compound represented by the formula (A1-3)] is preferable. Further, the (meth) acrylic acid ester (B1) having an aromatic ring and a (meth) acryloyloxy group in the molecule is preferably a polyfunctional (meth) acrylate, and in particular, the formula (B1-1), the formula (B1 -2) [especially, a compound represented by formula (B1-1)] is preferred. Furthermore, as the compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule, the compound represented by the above formula (C1-1) or formula (C1-2) [especially, Compound represented by C1-1)] is preferred.

In the combination (i), the blending ratio of (A1), (B1), and (C1) is 10 to 70% by weight of (A1) with respect to the curable composition (or the total amount of the curable compound). (Particularly 30 to 50% by weight), (B1) is 10 to 70% by weight (particularly 30 to 50% by weight), and (C1) is 1 to 50% by weight (particularly 10 to 30% by weight). The ratio of the total amount of (A1), (B1) and (C1) to the total amount of the curable compound is, for example, 60% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.

According to the curable composition of the combination of (i) above, both optical properties and physical properties are excellent, and the light transmittance (400 nm) of the resulting cured resin is, for example, 80% or more (preferably 85% or more). The internal transmittance (400 nm) is, for example, 85% or more (preferably 90% or more), the refractive index (589 nm) is, for example, 1.55 or more (preferably 1.60 or more), and the Abbe number is, for example, 35 or less ( It is preferably 30 or less), and can be a cured resin excellent in optical properties having high transparency and resolution. The water absorption is, for example, 2% by weight or less (preferably about 1% by weight), the glass transition point is, for example, 100 ° C. or more (preferably 120 ° C. or more), and the linear expansion coefficient is, for example, 120 ppm / K or less (preferably , 100 ppm / K or less), and the cure shrinkage rate is, for example, 10% or less (preferably 8% or less), and can be an excellent effect resin from the viewpoint of moldability and moisture resistance. Further, even when the cured resin is subjected to high temperature conditions (for example, about 260 ° C.), the light transmittance, the refractive index, and the Abbe number hardly change and the shape does not change.

In the combination of (ii) above, the epoxy compound having an alicyclic ring and an epoxy group in the molecule (however, having no aromatic ring) (A2) is preferably a polyfunctional epoxy compound. ) And a compound represented by the formula (A2-2) [particularly a compound represented by the formula (A2-2)] are preferable. The (meth) acrylic acid ester (but not having an aromatic ring) (B2) having an alicyclic ring and a (meth) acryloyloxy group in the molecule is preferably a polyfunctional (meth) acrylate. The compound represented by (B2-1) is preferable. Furthermore, as the compound (C1) having an epoxy group and a (meth) acryloyloxy group in the molecule, the compound represented by the above formula (C1-1) or formula (C1-2) [especially, Compound represented by C1-1)] is preferred.

In the combination (ii), the blending ratio of (A2), (B2), and (C1) is 10 to 70% by weight of (A2) with respect to the curable composition (or the total amount of the curable compound). (Particularly 30 to 50% by weight), (B2) is 10 to 70% by weight (particularly 30 to 50% by weight), and (C1) is 1 to 50% by weight (particularly 10 to 30% by weight). The ratio of the total amount of (A2), (B2) and (C1) to the total amount of the curable compound is, for example, 60% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.

According to the curable composition of the combination (ii), both optical properties and physical properties are excellent, and the light transmittance (400 nm) of the resulting cured resin is, for example, 80% or more (preferably 85% or more). The internal transmittance (400 nm) is, for example, 85% or more (preferably 90% or more), 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, it is 50 or more), and can be a cured resin excellent in optical properties having high transparency and resolution. The water absorption is, for example, 2% by weight or less (preferably about 1% by weight), the glass transition point is, for example, 100 ° C. or more (preferably 120 ° C. or more), and the linear expansion coefficient is, for example, 120 ppm / K or less (preferably , 100 ppm / K or less), and the cure shrinkage rate is, for example, 10% or less (preferably 8% or less), and can be an excellent effect resin from the viewpoint of moldability and moisture resistance. Further, even when the cured resin is subjected to high temperature conditions (for example, about 260 ° C.), the light transmittance, the refractive index, and the Abbe number hardly change and the shape does not change.

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.

In the present invention, curing of the curable composition comprising the combination of (ii) and the lens (low Abbe number lens resin) comprising the cured product (cured resin) of the curable composition comprising the combination of (i) above. By using in combination with a lens (a high Abbe number lens resin) made of an object (cured resin), a high resolution lens (lens unit) with extremely small chromatic aberration can be obtained.

[Other ingredients]
The curable composition of the present invention contains a cationic polymerization initiator, a curing agent, a curing accelerator, a radical polymerization initiator, a photosensitizer, and various additives depending on the type of the curable compound to be used. Also good.

The cationic polymerization initiator is an initiator (curing catalyst; acid generator) that releases a substance that initiates cationic polymerization by heating or light. As the cationic polymerization initiator, a thermal cationic polymerization initiator is preferable. The amount of the cationic polymerization initiator is, for example, 0 to 15% by weight, preferably 0.01 to 10% by weight, based on the whole cationic curable composition. By mix | blending in this range, favorable hardened | cured materials, such as heat resistance, transparency, a weather resistance, can be obtained.

Examples of the cationic polymerization initiator include aryldiazonium salts [for example, PP-33, manufactured by Asahi Denka Kogyo Co., Ltd.], aryliodonium salts, arylsulfonium salts [for example, FC-509, manufactured by 3M Corporation], UVE1014 [G. E. CP-66, CP-77 [Asahi Denka Kogyo Co., Ltd.], SI-60L, SI-80L, SI-100L, SI-110L [Sanshin Chemical Industry Co., Ltd.], Allen -Ion complexes [for example, CG-24-61 manufactured by Ciba Geigy Co., Ltd.]. Further, a system of a chelate compound of a metal such as aluminum or titanium and an acetoacetate ester or diketone and a silanol or phenol is also used. Examples of the chelate compound include aluminum trisacetylacetonate and aluminum trisacetoacetate ethyl. Examples of silanols or phenols include triphenylsilanol and bisphenol S.

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, and specifically, for example, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride , Dodecenyl succinic anhydride, methylendomethylenetetrahydrophthalic anhydride, and the like. In addition, acid anhydrides that are solid at room temperature, such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic acid anhydride, as long as the impregnation property 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 acid anhydride at room temperature and used as a liquid mixture at room temperature. The compounding amount of the curing agent varies depending on the kind and amount of the cationic curable compound in the cationic curable composition, but is 0 to 60% by weight, preferably 5 to 40% by weight based on the whole cationic curable composition. It is about wt%.

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 whole cationic curable composition. If the blending amount is too small, the curing accelerating effect may be insufficient, and if it is too large, the hue in the cured product 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, and 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; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone Any anthraquinones; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-isopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; benzophenones such as benzophenone Xanthones; 1,7-bis (9-acridinyl) heptane and the like.

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

Commercially available radical polymerization initiators include, for example, Irgacure (registered trademark) 184 (1-hydroxycyclohexyl phenyl ketone) and Irgacure (registered trademark) 500 (1-hydroxycyclohexyl) available from Ciba as photo radical polymerization initiators. Phenylketone, benzophenone), and other photopolymerization initiators of the Irgacure® type; Darocur® 1173, 1116, 1398, 1174, and 1020 (available from Merck).

The blending amount of the radical polymerization initiator varies depending on the kind and amount of the radical polymerizable compound in the cationic curable composition, but is, for example, about 0.1 to 20% by weight with respect to the whole cationic curable composition. .

The photosensitizer is preferably used in combination with a photopolymerization initiator. As the photosensitizer, those known and commonly used as photosensitizers can be used. For example, N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylamino is used. Tertiary amines such as benzoate, triethylamine, triethanolamine and the like can be mentioned. 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 with respect to the whole cationic curable composition.

Examples of additives that may be added to the cationic curable composition of the present invention include organosiloxane compounds, metal oxide particles, rubber particles, silicone-based and fluorine-based antifoaming agents, silane coupling agents, and fillers. , Plasticizers, leveling agents, antistatic agents, mold release agents, flame retardants, colorants, antioxidants, ultraviolet absorbers, ion adsorbers, pigments and the like. The compounding quantity of these various additives is 5 weight% or less with respect to the whole cationic curable composition, for example. The cationic curable composition of the present invention may contain a solvent, but if it is too much, bubbles may be generated in the cured resin. Therefore, the cationic curable composition is preferably 10% by weight or less, particularly 1%. % By weight or less.

The cationic curable composition of the present invention includes, for example, a predetermined amount of a cationic polymerizable compound and the specific organic sulfur compound, and a radical polymerizable compound, a cationic polymerization initiator, a curing agent, and a curing accelerator that are added as necessary. , A radical polymerization initiator, a photosensitizer, various additives, and the like, and are prepared by 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 stirring and 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 cationic curable composition of the present invention provides a cured resin that is hard to be yellowed even at high temperatures by curing. Therefore, in particular, optical applications (optical material applications), optical device applications, display device applications, and electrical / electronic component material applications. Etc. can be suitably used.

The cured product of the present invention can be obtained by curing the cationic curable composition. As a curing method, an appropriate method can be selected from known curing methods according to the type of the curable compound in the curable composition. For example, the cationic curable composition can be placed in a mold that matches the shape of the cured product, cured by irradiation with active energy rays (for example, ultraviolet rays), and further heated to obtain the desired cured product. . Moreover, the target hardened | cured material can also be obtained only by heating. When ultraviolet rays are used as the active energy ray, the irradiation amount is, for example, about 1000 to 4000 mJ / cm ² . The heating temperature varies depending on the type of the curable compound, but is, for example, about 80 to 200 ° C., preferably about 110 to 160 ° C. In addition, after taking out hardened | cured material from a metal mold | die, you may post-cure (bake).

As described above, the cured product of the present invention is suitably used as an optical member because yellowing is remarkably suppressed even at a high temperature of about 260 ° C., for example. 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 include a display protective film, a display backlight, a light guide plate, and an antireflection film.

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

Example 1
Epoxy compound [1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol, which is included in the compound represented by the formula (A2-2); Daicel Chemical Industries, Ltd., trade name “EHPE3150” 30 parts by weight, (meth) acrylic acid ester [tricyclo [5.2.1.0 ^2,6 ] decanedimethanol diacrylate, the above formula (B2-1) 50 parts by weight of a product name “IRR214K” manufactured by Daicel Cytec Co., Ltd., and a (meth) acrylic ester having an epoxy group [epoxidized dicyclopentenyl acrylate (= 3,4-epoxy) tricyclo [5.2.1.0 ^2,6] decan-8-yl acrylate and 3,4-epoxytricyclo [5.2.1.0 ^2,6] decane-9-b Acrylate, contained in the compound represented by the above formula (C1-1); Daicel Chemical Industries, Ltd., trade name “E-DCPA”], 20 parts by weight, acid generator (arylsulfonium salt acid generator; 1 part by weight of a trade name “CPI-100P”), 1 part by weight of a radical generator (acetophenone radical generator; trade name “Irgacure 184”, manufactured by Ciba Geigy), and decanethiol (organic) 1 part by weight of a sulfur compound (C ₁₀ H ₂₁ SH) was added, and the mixture was stirred and mixed with a rotation / revolution mixer to obtain a uniform and transparent curable composition (optical material composition liquid). The obtained optical material composition liquid was cast into a glass mold having a thickness of 0.5 mm in which a release agent was previously applied and evaporated.
Next, the cast optical material composition is irradiated with ultraviolet rays (irradiation amount: 2,600 mJ / cm ² ) to produce a cured resin, and the produced cured product is heated at 160 ° C. for 1 hour in an air atmosphere. A plate-shaped transparent and uniform cured resin having a thickness of 0.5 mm was obtained. This cured resin could be easily released from the glass mold. The obtained cured resin was subjected to the evaluation described later.

Example 2
A cured resin was obtained in the same manner as in Example 1 except that 1,10-decanedithiol (HS—C ₁₀ H ₂₁ —SH) was used instead of decanethiol.

Example 3
A cured resin was obtained in the same manner as in Example 1 except that didecyl sulfide (n-decyl sulfide; C ₁₀ H ₂₁ —S—C ₁₀ H ₂₁ ) was used instead of decanethiol.

Example 4
A cured resin was obtained in the same manner as in Example 1 except that didecyl disulfide [(C ₁₀ H ₂₁ —S—) ₂ ] was used instead of decanethiol.

Comparative Example 1
A cured resin was obtained in the same manner as in Example 1 except that no organic sulfur compound was blended.

Comparative Example 2
Instead of blending organic sulfur compounds, 1 part by weight of hindered phenolic antioxidant (Ciba Specialty Chemicals, trade name “Irg1010”) and phosphorus antioxidant (product of Sanko Co., Ltd., product) The name “HCA”) was blended in an amount of 1 part by weight, and a cured resin was obtained in the same manner as in Example 1.

Viscosity measurement of curable compositions obtained in Examples and Comparative Examples, characteristics of cured resins obtained in Examples and Comparative Examples, and heat resistance test (evaluation of yellowing resistance under reflow conditions) are as follows. And conditions. The results are shown in Table 1. In Table 1, “-” in Comparative Example 2 indicates that it has not been evaluated.

(1) Viscosity Viscosity of the curable composition was measured using an R / S rheometer (trade name “PHYSICA UDS200 / Paar”, manufactured by Physica) at a rotational speed D = 20 / s at 25 ° C.

(2) Shape of resin surface The presence or absence of pulse separation on the resin surface of the cured resin was examined visually. The pulse separation means an optically inhomogeneous state, and indicates wrinkles and fluctuations observed on the surface of the cured resin.

(3) Internal transmittance The internal transmittance of the cured resin was calculated by the following equation.
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. The light transmittance at 400 nm was measured using a spectrophotometer (trade name “U-3900” manufactured by Hitachi High-Technologies Corporation), and the refractive index was the value of the refractive index at 400 nm measured by the following method (4). Was used.

(4) Refractive index The refractive index of the cured resin was measured by a method based on JIS K7142, using a refractometer (trade name “Model 2010” manufactured by Metricon Co., Ltd.) at 589 nm at 25 ° C.

(5) Linear expansion coefficient The linear expansion coefficient of the cured resin was measured using a TMA measuring device (trade name “TMA / SS100” manufactured by SII Nano Technology Co., Ltd.), a heating rate of 5 ° C./min, and a measurement temperature range of 30 ° C. The coefficient of thermal expansion was measured at ˜250 ° C., and the slope of the straight line on the low temperature side was expressed as the coefficient of linear expansion.

(6) Elastic Modulus The elastic modulus of the cured resin was measured using a solid viscoelasticity measuring device (trade name “RSAIII”, manufactured by TA Instruments Inc.) with a temperature rising rate of 5 ° C./min and a measurement temperature range of −30. The dynamic viscoelastic properties were measured at 270 ° C to 270 ° C, and the elastic modulus at 25 ° C was read.

(7) Glass transition temperature The glass transition temperature of the curable resin is determined by using a differential scanning calorimeter (trade name “Q2000”, manufactured by T.A. Instruments Co., Ltd.) and pretreatment (at a heating rate of 20 ° C./min). After heating from -50 ° C to 250 ° C and cooling rate of 20 ° C / min, cooling from 250 ° C to -50 ° C), measured at a temperature rise rate of 20 ° C / min and measurement temperature range of -50 ° C to 250 ° C did.

(8) Water absorption The water absorption of the cured resin was measured by a method based on JIS K7209.

(9) Heat resistance test (evaluation of yellowing resistance under reflow conditions)
After three consecutive heat resistance tests in which the cured resin was preheated to 270 ° C. for 1 minute in an air atmosphere, the transmittance at 400 nm and the refractive index at 400 nm of the cured resin subjected to the heat resistance measurement were measured. The internal transmittance was calculated.
Yellowing resistance under reflow conditions was evaluated using the rate of decrease in internal transmittance calculated from the following formula as the yellowing rate.
Those having a yellowing rate of 3% or less have high transparency even after the heat resistance test, and can be suitably used as an optical material such as a lens.
Decrease rate of internal transmittance (%) = (Internal transmittance before heat test-Internal transmittance after heat test) / (Internal transmittance before heat test) · 100

In comparison between Examples 1 to 4 and Comparative Example 1, a heat resistance test using an organic sulfur compound such as a thiol compound and a sulfide compound, specifically, a yellowing suppression effect under reflow conditions is observed. Moreover, it is recognized from the comparison with the comparative example 2 that organic sulfur compounds, such as a thiol compound and a sulfide compound, have a higher yellowing suppression effect under a heat resistance test than a conventional antioxidant. Therefore, a cured resin obtained from a curable resin composition containing an organic sulfur compound such as a thiol compound or a sulfide compound has high transparency even after a heat test, and is used for optical applications such as lens units and optical device applications. It can use suitably for various uses.

According to the curable composition of the present invention, it is possible to obtain a cured resin excellent in yellowing resistance that is hard to yellow even under high temperature by curing. In particular, the use of optical members such as lenses and the use of optical devices It is suitable for various uses such as.

Claims

A curable composition comprising a cationically polymerizable compound and at least one organic sulfur compound selected from a thiol compound, a dithiol compound, a sulfide compound and a disulfide compound.
The curable composition according to claim 1, wherein the organic sulfur compound has a boiling point of 100 ° C. or higher.
The curable composition according to claim 1 or 2, wherein the cationic polymerizable compound is at least one compound selected from an epoxy compound, an oxetane compound and a vinyl ether compound.
The curable composition according to any one of claims 1 to 3, further comprising a radical polymerizable compound.
The curable composition according to claim 4, wherein the radical polymerizable compound is a (meth) acrylic acid ester compound.
The curable composition according to any one of claims 1 to 5, further comprising a compound having a cationic polymerizable group and a radical polymerizable group in the molecule.
A cured resin obtained by curing the curable composition according to any one of claims 1 to 6.
An optical member made of the cured resin according to claim 7.