JP2012136571A - Cationic curing resin composition for optical lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cationic curing resin composition for an optical lens, which can obtain an optical lens in which hygroscopicity is low, excellent optical characteristics can be maintained in a severe use environment, and further mold transferability is also excellent.SOLUTION: The cationic curing resin composition for an optical lens includes: an epoxy compound; an oxetane compound; and a cationic curing catalyst as essential components, wherein at least ≥60 mass% in 100 mass% of the epoxy compound is a hydrogenation epoxy compound.

Description

The present invention relates to a cationic curable resin composition for optical lenses. More specifically, for example, the present invention relates to a cationic curable resin composition for an optical lens that is suitably used for an optical lens such as an LED lens, an imaging lens, or a pickup lens.

The cationic curable resin composition is a resin composition that contains a cationic curable compound and a cationic curing catalyst, generates cationic species from the catalyst by heat or light, and can be cured by a cationic curing reaction. Cationic curing (polymerization) has advantages in that curing inhibition by oxygen does not occur and shrinkage during curing is small compared to radical polymerization, and application to various fields is expected. Specifically, for example, various applications such as electrical / electronic members, optical members, molding materials, paints, adhesive materials, etc. have been studied, and the properties required for each application are excellent. Development of a cationic curable resin composition is desired.

Conventionally, what contains an epoxy compound is known as a cationic curable resin composition, for example. Patent Document 1 discloses a curable resin composition containing an epoxy compound and an oxetane compound as a cationic polymerizable compound and a specific cationic polymerization initiator, and can be used in a high temperature environment or a high temperature and high humidity environment. Further, it is described that adhesion of an optical device can be realized over a long period of time without causing problems such as formation of a salt with an alkali metal, corrosion of the metal, or peeling.
Patent Document 2 describes that a photocurable resist composition containing an epoxy resin, a specific photolatent polymerization initiator, and a sensitizer is excellent in tack freezing and deep curability of a coating film. Yes.

Since the cationic curable resin composition can also exhibit transparency, it is useful as a material for an optical lens in an imaging device or the like. In the optical field, for example, since a digital camera module is mounted on a mobile phone or the like, downsizing and cost reduction are required. Therefore, resin lenses are increasingly used as imaging lenses instead of conventional inorganic glass. In addition, the use of a cationic curable resin composition as a material for a resin lens has been studied. For example, an ultraviolet curable resin composition containing a polyfunctional cycloaliphatic epoxy resin, a polyfunctional oxetane compound, and a photopolymerization initiator in specific ratios is disclosed (for example, see Patent Document 3). Patent Document 3 describes that such a resin composition is suitable for an optical lens having an Abbe number of 50 or more and excellent in heat discoloration and transparency.
Further, for the purpose of obtaining an optical lens having excellent transparency and heat resistance reliability, a method for producing an optical lens comprising a step of ultraviolet curing a resin composition containing a polyfunctional epoxy resin, an oxetane compound and a photoacid generator Is disclosed (for example, see Patent Document 4).

JP 2008-308589 A JP 2002-256063 A JP 2010-150489 A JP 2009-288598 A

As described above, various cationic curable resin compositions have been studied. However, a cured product obtained by cationic curing of an epoxy compound has a problem that the hygroscopicity is increased. In particular, in optical lens applications, there is a problem that the transparency of the lens decreases with time under high humidity conditions. As described above, with the expansion of applications and demand for resin lenses in the optical field, there is a demand for optical lenses that can maintain excellent optical characteristics over a long period of time under various usage environments. Furthermore, there is an increasing demand for miniaturization and miniaturization of optical lenses, and the resin composition that is the material is also required to have high-precision molding processability. As described above, there is room for devising to obtain a cationic curable resin composition that is suitable for a material of an optical lens having superior durability and also excellent in moldability.

The present invention has been made in view of the above situation, and has an optical lens that has low hygroscopicity, can maintain excellent optical characteristics even in harsh usage environments, and has excellent mold transferability. It is an object of the present invention to provide a cationic curable resin composition for an optical lens that can be obtained.

The present inventor paid attention to a cationic curable resin composition containing an epoxy compound and an oxetane compound as a cationic curable compound in various studies on a cationic curable resin composition for obtaining an optical lens having low hygroscopicity. And when the specific ratio was made into the hydrogenated epoxy compound among the total amount of the said epoxy compound, it discovered that the hygroscopic property of the hardened | cured material obtained became low. Furthermore, it has also been found that by using a hydrogenated epoxy compound and an oxetane compound in combination, the hygroscopicity of the cured product can be further suppressed, and the resin composition is excellent in high-precision molding processability. The cured product as described above can exhibit stable optical characteristics even under harsh environments such as high temperature and high humidity, and can be processed into a fine shape with high precision and excellent mold transferability. Thus, the inventors have found that the present invention is extremely useful as an optical lens, and have conceived that the above-mentioned problems can be solved brilliantly, and have reached the present invention.

That is, the present invention is a cationic curable resin composition for an optical lens comprising an epoxy compound, an oxetane compound and a cationic curing catalyst as essential components, wherein 60% by mass or more of the total amount of the epoxy compound is 100% by mass. It is a cationic curable resin composition for optical lenses, which is a compound.
The present invention is described in detail below.

The cation curable resin composition for optical lenses of the present invention (hereinafter also referred to as a cation curable resin composition or simply a resin composition) includes an epoxy compound, an oxetane compound and a cation curing catalyst. As long as, other components may be included, and each component may be used alone or in combination of two or more.

The epoxy compound is a compound having one or more epoxy groups in the molecule. The epoxy group includes an oxirane ring which is a three-membered ether, and includes a glycidyl group (including a glycidyl ether group and a glycidyl ester group) in addition to an epoxy group in a narrow sense.
In the cationic curable resin composition for optical lenses, 60% by mass or more of the total amount of the epoxy compound is 100% by mass, which is a hydrogenated epoxy compound. As a result, the moisture absorption rate of the cured product can be suppressed to less than 1.00%, which is a preferable range, so that a decrease in transparency due to moisture absorption of the cured product can be suppressed, and further, coloring by heat or ultraviolet rays or short wavelength light can be suppressed. The effect that the fall of the transmittance | permeability of is suppressed is acquired. As a result, when the cured product is applied to an optical lens, the optical characteristics are stabilized.
On the other hand, if the content of the hydrogenated epoxy compound is less than 60% by mass, the hygroscopicity of a cured product obtained by curing the resin composition cannot be sufficiently lowered. The content of the hydrogenated epoxy compound with respect to 100% by mass of the total amount of the epoxy compound is preferably 70% by mass or more, more preferably 80% by mass or more, most preferably 100% by mass, that is, the total amount of the epoxy compound is hydrogenated. It is an epoxy compound.

The oxetane compound is a compound having one or more oxetane rings in the molecule. When the cation curable resin composition for optical lenses has an oxetane compound as an essential component together with the hydrogenated epoxy compound, the hygroscopic property of the resulting cured product can be further reduced, and the heat and moisture resistance can be sufficiently improved. Can do. Specifically, even when heated under high-humidity conditions, a decrease in visible light permeability of the cured product can be sufficiently suppressed.
In addition, since the oxetane compound having a relatively low molecular weight can be used, the resin composition can be reduced in viscosity even in a solventless system, and the processing characteristics can be improved. If the resin composition contains a solvent, there may be bubbles in the cured product due to the curing step, or the smoothness of the cured product surface may be impaired, but if it can be handled without a solvent as described above, Even when a complex-shaped cured product is produced by mold molding, a cured product having excellent transferability can be obtained.
Furthermore, since the resin composition has an oxetane compound as an essential component, it has excellent photocationic curability, so that it can be cured and molded at a lower temperature than thermosetting.

The oxetane compound is not particularly limited as long as it is a compound having one or more oxetane rings in the molecule as described above, but is a polyfunctional oxetane compound, that is, a molecule in that the strength of the cured product can be improved. A compound having two or more oxetane rings is preferable.

In the cation curable resin composition for an optical lens, the mass ratio of the oxetane compound to the total amount of the epoxy compound is preferably 1.0 or more. Thereby, the hygroscopic property of the hardened | cured material obtained using the said resin composition can be suppressed more fully. More preferably, it is 1.5 or more as said mass ratio, More preferably, it is 2.0 or more. The mass ratio is more preferably 10.0 or less, and still more preferably 4.0 or less.

In the cationic curable resin composition for optical lenses, the total amount of the epoxy compound and the oxetane compound is 40% by mass or more with respect to 100% by mass of the total amount of the cured product-forming components in the resin composition. Preferably there is. Thereby, the hygroscopic property of the hardened | cured material obtained using the said resin composition can be suppressed more fully. More preferably, it is 50 mass% or more as a total amount of the said epoxy compound and the said oxetane compound, More preferably, it is 60 mass% or more.
The total amount of the cured product-forming component refers to the total amount of the epoxy compound and the oxetane compound (in terms of non-volatile content), or in the form in which the metalloxane component is contained in the resin composition as described later, the epoxy compound, the oxetane compound, and This means the total amount of metalloxane components (nonvolatile content equivalent).
The total amount is preferably 100% by mass or less. However, as will be described later, when a metalloxane component is added for the purpose of suppressing sink of the cured product or increasing the hardness of the cured product, an addition amount capable of sufficiently exerting the effect of the addition of the component is necessary. Therefore, the total amount of the epoxy compound and the oxetane compound is more preferably 90% by mass or less. More preferably, it is 80 mass% or less.

The cation curing catalyst is not particularly limited as long as it is a compound capable of generating a cationic species that initiates polymerization by photoexcitation or heat, but is preferably a photo cation curing catalyst or a thermal cation curing catalyst. By using a photocationic curing catalyst, a compound containing a cationic species is excited by light, a photodecomposition reaction occurs, and photocuring proceeds. In addition, by using a thermal cation curing catalyst, a compound containing a cation species is excited by heating, a thermal decomposition reaction occurs, and thermal curing proceeds. Among these, it is more preferable to use a photocationic curing catalyst because it can be cured and molded at a relatively low temperature. Thereby, even if it is a case where the said resin composition contains a solvent, the disorder | damage | failure of the bubble in hardened | cured material and hardened | cured material surface can be suppressed.
Thus, the form in which the cation curing catalyst is a photocationic curing catalyst is one of the preferred forms of the present invention.

The cationic curable resin composition for optical lenses may contain a solvent as long as the effects of the present invention are not impaired. However, as described above, if the resin composition contains a solvent, bubbles may be generated in the cured product during the curing process or the smoothness of the surface of the cured product may be impaired. It is preferable that a small amount is contained or not contained. Specifically, the content of the solvent with respect to 100% by mass of the total amount of the resin composition is preferably 10% by mass or less. The content of the solvent is more preferably 5% by mass or less, most preferably 0% by mass, that is, the resin composition does not contain a solvent.

Below, the preferable form of the cation curable resin composition for optical lenses of this invention is demonstrated more concretely.

As the hydrogenated epoxy compound, it is preferable to use a hydrogenated epoxy compound having an average of two or more epoxy groups in one molecule, that is, a polyfunctional hydrogenated epoxy compound. Such a hydrogenated epoxy compound is preferably a polyfunctional glycidyl ether compound having an average of two or more glycidyl ether groups bonded directly or indirectly to a saturated aliphatic cyclic hydrocarbon skeleton. Such a hydrogenated epoxy compound is preferably a complete or partial hydrogenated product of an aromatic polyfunctional epoxy compound, and more preferably a hydrogenated product of an aromatic polyfunctional glycidyl ether compound.
The hydrogenated epoxy compound also preferably has a weight average molecular weight of 300 or more, and preferably less than 8000.
The weight average molecular weight in the present specification can be measured by gel permeation chromatography (column: TSKgel SuperMultipore HZ-N 4.6 ^* 150, eluent: tetrahydrofuran, standard sample: TSK polystyrene standard).

Specific examples of the hydrogenated epoxy compound include a hydrogenated bisphenol A type epoxy compound represented by the following general formula (1-1) and a hydrogenated bisphenol F type epoxy represented by the following general formula (1-2). Compounds are preferred.
In the general formulas (1-1) and (1-2), a part or all of hydrogen atoms of hydrocarbons such as a cyclohexyl ring and a methylene chain may be substituted. As the substituent, a halogen atom such as fluorine, chlorine and bromine, a hydrocarbon group which may have a substituent, and the like are preferable. Among the hydrocarbon groups, an alkyl group is preferable, and a methyl group and an ethyl group are more preferable.

式中、ｑは０以上の整数を表す。

In the formula, q represents an integer of 0 or more.

In the embodiment in which the hydrogenated epoxy compound is a hydrogenated bisphenol A type epoxy compound and / or a hydrogenated bisphenol F type epoxy compound, the hydrogenation rate of the hydrogenated epoxy compound is preferably greater than 95%. When the hydrogenation rate is greater than 95%, the aromatic cyclic structure contained in the hydrogenated epoxy compound is sufficiently reduced, so that coloring (yellowing) of the resulting cured product due to heat and light can be sufficiently suppressed. it can. More preferably, the hydrogenation rate is greater than 98%, and still more preferably, the hydrogenation rate is 100%.

Specific examples of the hydrogenated bisphenol A type epoxy compound include those obtained by hydrogenating a bisphenol A type epoxy compound, such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), YX-8040. (Manufactured by Mitsubishi Chemical Corporation), ST-4000D (manufactured by Nippon Steel Chemical Co., Ltd.) and the like.
As the hydrogenated bisphenol F-type epoxy compound, specifically, those obtained by hydrogenating a bisphenol F-type epoxy compound can be used.
In addition, in this specification, the compound etc. in which the manufacture or sales company name was shown shall represent a brand name.

The said epoxy compound may contain epoxy compounds other than a hydrogenated epoxy compound, as long as 70 mass% or more in the total amount of 100 mass% is a hydrogenated epoxy compound.
Examples of the epoxy compound other than the hydrogenated epoxy compound include an aromatic epoxy compound and an alicyclic epoxy compound. From the viewpoint of suppressing the hygroscopicity of the cured product, an aromatic epoxy compound is preferable. . Moreover, the refractive index of hardened | cured material can also be raised when an aromatic epoxy compound is used. On the other hand, when an alicyclic epoxy compound is used, the curability of the resin composition can be improved, and the obtained cured product can be excellent in heat resistance and light resistance.

The aromatic epoxy compound is a compound having an aromatic ring and an epoxy group in the molecule, for example, a glycidyl compound having an aromatic ring conjugated system such as a bisphenol skeleton, a fluorene skeleton, a biphenyl skeleton, a naphthalene ring, or an anthracene ring. It is preferable.

As the aromatic epoxy compound, for example, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a fluorene type epoxy compound, an aromatic epoxy compound having a bromo substituent, and the like are preferable. A fluorene epoxy compound is preferred. Specifically, bisphenol A type epoxy compound (Japan Epoxy Resin Co., Ltd., 828EL, 1003 or 1007), bisphenol F type epoxy compound, fluorene type epoxy compound (Osaka Gas Chemical Co., Ltd., ONCOAT EX-1020 or OGSOL EG-) 210), a fluorene-based epoxy compound (Osaka Gas Chemical Co., Ltd., ONCOAT EX-1010 or OGSOL PG) and the like are preferably used. More preferred are bisphenol A type epoxy compounds and fluorene type epoxy compounds (Ossol EG-210, manufactured by Osaka Gas Chemical Company).

As the aromatic epoxy compound, an aromatic glycidyl ether compound is also suitable, but as the aromatic glycidyl ether compound, for example, an epibis type glycidyl ether type epoxy resin, a high molecular weight epibis type glycidyl ether type epoxy resin, A novolak aralkyl type glycidyl ether type epoxy resin may be mentioned.
As said epibis type glycidyl ether type epoxy resin, what is obtained by condensation reaction of bisphenols, such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, and epihalohydrin, for example is suitable.
The high molecular weight epibis type glycidyl ether type epoxy resin can be obtained, for example, by subjecting the epibis type glycidyl ether type epoxy resin to an addition reaction with bisphenols such as bisphenol A, bisphenol F, bisphenol S, and fluorene bisphenol. Are preferred.

Examples of the novolak aralkyl type glycidyl ether type epoxy resin include phenols, cresol, xylenol, naphthol, resorcin, catechol, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, and other phenols, formaldehyde, acetoaldehyde, propion Polyhydric phenols obtained by condensation reaction of aldehyde, benzaldehyde, hydroxybenzaldehyde, salicylaldehyde, dicyclopentadiene, terpene, coumarin, paraxylylene glycol dimethyl ether, dichloroparaxylylene, bishydroxymethylbiphenyl, etc., and epihalohydrin What is obtained by performing a condensation reaction is suitable.

Examples of the aromatic epoxy compound further include, for example, an aromatic crystalline epoxy resin obtained by condensation reaction of tetramethylbiphenol, tetramethylbisphenol F, hydroquinone, naphthalene diol, and the like with epihalohydrin, and the bisphenols and tetramethyl. High molecular weight polymer of aromatic crystalline epoxy resin obtained by addition reaction of biphenol, tetramethylbisphenol F, hydroquinone, naphthalene diol, etc .; obtained by condensation reaction of tetrahydrophthalic acid, hexahydrophthalic acid, benzoic acid and epihalohydrin The glycidyl ester type epoxy resin etc. which can be used can also be used.

The alicyclic epoxy compound is a compound having an alicyclic epoxy group. Examples of the alicyclic epoxy group include an epoxycyclohexane group (epoxycyclohexane skeleton), an epoxy group added to a cyclic aliphatic hydrocarbon directly or via a hydrocarbon, and the like. Among these, a compound having an epoxycyclohexane group is preferable. Moreover, the polyfunctional alicyclic epoxy compound which has two or more alicyclic epoxy groups in a molecule | numerator is suitable at the point which can raise a hardening rate more. A compound having one alicyclic epoxy group in the molecule and an unsaturated double bond group such as a vinyl group is also preferably used.

Examples of the epoxy compound having an epoxycyclohexane group include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, epsilon-caprolactone modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxy. Cyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate and the like are suitable. Examples of the alicyclic epoxy compound other than the epoxy compound having the epoxycyclohexane group include 1,2-epoxy-4- (2-oxiranyl) cyclohexane of 2,2-bis (hydroxymethyl) -1-butanol. Examples include adducts and alicyclic epoxides such as epoxy resins containing heterocycles such as triglycidyl isocyanurate.

As content of the said epoxy compound (Epoxy compound other than a hydrogenated epoxy compound and a hydrogenated epoxy compound) in the said cationic curable resin composition for optical lenses, the total amount of the hardened | cured material formation component in the said resin composition is 100 mass. % Is preferably 10% by mass or more and 45% by mass or less. More preferably, they are 15 mass% or more and 40 mass% or less, More preferably, they are 15 mass% or more and 35 mass% or less.

The oxetane compound is not particularly limited as long as it has one or more oxetane rings in one molecule, and any of them is effective for improving the processing characteristics by reducing the viscosity of the resin composition and suppressing the hygroscopicity of the cured product. However, from the viewpoint of improving the refractive index, it is preferable to use an oxetane compound having an aromatic ring in the molecule. On the other hand, the use of an aliphatic oxetane compound from the viewpoint of improving the above-described processing characteristics and suppressing hygroscopicity without lowering the Abbe number of the cured product, and improving heat resistance and light resistance. preferable. Here, “aliphatic oxetane compound” means an oxetane compound having no aromatic ring in the molecule. On the other hand, as described above, from the viewpoint of improving the strength of the cured product, it is preferable to use a polyfunctional oxetane compound, that is, a compound having two or more oxetane rings in one molecule. Moreover, the hygroscopic property of hardened | cured material can further be suppressed by using what has little content rate of polar parts, such as ester group, in a structure.

Among the aliphatic oxetane compounds, examples of monofunctional oxetane compounds include 3-methyl-3-hydroxymethyl oxetane, 3-ethyl-3-hydroxymethyl oxetane, 3-ethyl-3- (2-ethylhexane). Siloxymethyl) oxetane, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, and the like are preferable.

Among the oxetane compounds having an aromatic ring, monofunctional oxetane compounds include, for example, 3-methyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, dicyclopentadiene (3- Ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether and the like are preferable.

Among the aliphatic oxetane compounds, examples of the polyfunctional oxetane compound include di [1-ethyl (3-oxetanyl)] methyl ether, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3- Oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3) -Oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) he Sun, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol Hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether and the like are preferable.

Among the oxetane compounds having an aromatic ring, examples of the polyfunctional oxetane compound include phenol novolac oxetane, dioxetane compound having a biphenyl skeleton (Ube Industries, ETERNACOLL (R) OXBP), and dioxetane compound having a phenyl skeleton ( Ube Industries, Ltd., ETERNACOLL (R) OXTP, ETERNCOLL (R) OXIPA), isophthalic acid-bis [(3-ethyloxetane-3-yl) methyl], a dioxetane compound having a fluorene skeleton, and the like are preferable.

The content of the oxetane compound in the cationic curable resin composition for optical lenses is 10% by mass or more and 95% by mass or less with respect to 100% by mass of the total amount of the cured product-forming components in the resin composition. It is preferable. If it exceeds 95% by mass, the resin composition may not be cured and a cured product may not be obtained. More preferably, they are 15 mass% or more and 50 mass% or less, More preferably, they are 15 mass% or more and 40 mass% or less.

The cationic curable resin composition for optical lenses preferably contains a metalloxane component (metalloxane compound). Thereby, the hardness of the hardened | cured material obtained can be improved. Further, since the shrinkage rate at the time of curing of the resin composition is lowered, the cured product sinks (the cured product is detached from the mold such as a mold due to the shrinkage in the curing step, and a step, a dent, or the like is generated on the surface of the cured product. Occurrence) is sufficiently suppressed, and the surface smoothness and the mold transferability are excellent.
The metalloxane compound is a compound having a metalloxane bond (MOM bond, where M represents a silicon atom or a metal atom). Examples of the metalloxane compound include a polymetalloxane compound and metal oxide particles.

The polymetalloxane compound is preferably a compound further having a condensable group in addition to the metalloxane bond. The group that can be condensed means a functional group that condenses by heating. Specific examples of the condensable group include, for example, a M-O-R group (R represents an alkyl group, an aryl group or an aralkyl group), a M-OH group, a M-X group (X is a halogen atom). Represents an atom), and MH groups are preferred. Among these condensable groups, an M—O—R group or an M—OH group is particularly preferable from the viewpoint of curing reactivity.

Although it does not specifically limit as said polymetalloxane compound, The atom represented by M is Si, Mg, Al, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Zr. Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, Ta, W, Ir, Tl, Pb, Bi, and Ra are preferably included in one or more. . More preferably, M includes one or more of Si, Al, Ti, Zn, Zr, Sn, Ba, and Ra, and more preferably Si, Ti, Zn, and Zr. Of these, one or more are included. Particularly preferably, from the viewpoint of stability of the compound and ease of production, it is preferable that M is Si and / or Ti, that is, that at least one of a polysiloxane compound, a polytitanoxane compound and a polytitanosiloxane compound is included. .
When the said polymetalloxane compound contains a polysiloxane compound, it is preferable that it is 30 mass% or more as content of a siloxane bond with respect to 100 mass% of total amounts of all the metalloxane bonds. More preferably, it is 50 mass% or more, More preferably, it is 80 mass% or more.

In the M-O-R group, R represents an alkyl group, an aryl group, or an aralkyl group, and may have two or more of these. Moreover, it is suitable that carbon number is 1-20. More preferably, it is 1-8, More preferably, it is 1-3.
Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl, and 2-ethyl. Chain alkyl group such as xyl group, n-octyl group, lauryl group, stearyl group; cycloalkyl group such as cyclopropyl group, cyclobutyl group, cyclohexyl group, bicyclohexyl group; one of hydrogen atoms of chain alkyl group A group in which part or all are substituted with a cycloalkyl group; a group in which some or all of the hydrogen atoms of a cycloalkyl group are substituted with a chain alkyl group, and the like.
Examples of the aryl group include a phenyl group, a naphthyl group, an anthranyl group and the like, and a group in which part or all of these hydrogen atoms are substituted with an alkyl group (for example, a methylphenyl group (toluyl group), Dimethylphenyl group (xylylene group), diethylphenyl group, etc.).
Examples of the aralkyl group include a benzyl group and the like, and a group in which some or all of these hydrogen atoms are substituted with an alkyl group (for example, a methylbenzyl group).

Among the R, an alkyl group (that is, a form in which the RO group is an alkoxy group) is preferable, and an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group is particularly preferable. is there. This makes it possible to further reduce shrinkage in the thermosetting process. A methyl group or an ethyl group is more preferable, and an ethyl group is most preferable because the reaction can be easily controlled.
R may have a substituent. Further, it may be a chain (linear or branched) structure or a cyclic structure.
The halogen atom represented by X is not particularly limited, but a fluorine atom is particularly preferred.

Although it does not specifically limit as a molecular structure of the said polymetalloxane compound, Usually, a chain structure (straight chain shape, branched shape), a ladder-like structure, a cyclic structure, a cage | basket shape, and a particulate form are illustrated. Among these, a chain shape, a ladder shape, and a cage shape are preferable because of high solubility in an epoxy compound, an oxetane compound, and the like. Further, a chain shape and a ladder shape are more preferable, and a ladder shape is particularly preferable in that a cured product having high solubility and higher optical transparency and mechanical properties can be obtained. In particular, when a ladder-shaped polymetalloxane compound is used, the release property, controllability of optical properties (transparency, Abbe number, refractive index, etc.), machine, etc. can be added with a small amount compared to the case of using other structures. The characteristic can be further improved. That is, (1) the cured product can be easily released from the molding die after curing (excellent mold release properties), (2) the transparency, Abbe number and refractive index of the resin composition are strictly Can be controlled (excellent controllability), (3) transparency, Abbe number and refractive index of the cured product can be strictly controlled (excellent controllability), (4) machine of cured product Additive effects such as excellent mechanical properties (elastic modulus and high breaking strength) can be exhibited.
The polymetalloxane compound may be liquid at room temperature or may be solid.

As a weight average molecular weight of the said polymetalloxane compound, 300 or more are preferable and it is preferable that it is 100,000 or less. If it is less than 300, the storage stability of the resin composition containing the polymetalloxane compound may not be sufficient, and the releasability, controllability of optical properties, and mechanical properties may not be further improved. There is. If it exceeds 100,000, there is a possibility that the compatibility with an epoxy compound, an oxetane compound or the like cannot be made more satisfactory. More preferably, it is 500 or more, More preferably, it is 1000 or more, More preferably, it is 50,000 or less, More preferably, it is 10,000 or less.

In the form in which the polymetalloxane compound contains a polysiloxane compound, examples of the polysiloxane compound include chain silicone compounds such as polydimethylsiloxane and polydiphenylsiloxane, and polysilsesquioxane (mainly containing silsesquioxane units). Polysiloxane). The shape of these molecules is not particularly limited, and examples thereof include a straight chain, a branched chain (including a network), a ring, and a bowl.

In the form in which the polysiloxane compound is polysilsesquioxane, a structural unit having a silicon atom bonded to three silicon atoms through a siloxane bond (Si—O—Si bond), that is, a silsesquioxane unit is particularly preferable. And a compound containing a condensable group in the molecule (this compound is referred to as “silsesquioxane having a condensable group”, simply “silsesquioxane”, or “polysilsesquioxane”). It is also called.) Such a polysiloxane compound is, for example, the following average composition formula (2):
R ¹ xYySiOz (2)
(R ¹ represents an alkyl group, an aryl group, or an aralkyl group. Y represents a condensed group or a condensed atom, and is bonded to Si to form the condensable group. X, y, and z are , Represents the average value of the bonding ratio of R ¹ , Y and O to Si, respectively, 0 <x <2, 0 <y <2, 1 <z <2, 0 <(x + y) <2, and x + y + 2z = 4) is particularly preferred. By using such silsesquioxane, the heat resistance and mechanical properties are improved and improved, and the increase in viscosity of the resin composition with time is suppressed. Therefore, the resin composition can be made into a one-pack type resin composition (one-part curable resin composition) that is superior in handling properties, and a cured product having excellent physical properties can be obtained more efficiently and simply. It becomes possible to obtain.

In the average composition formula (2), R ¹ represents an alkyl group, an aryl group, or an aralkyl group, and these carbon numbers are preferably 1-20. More preferably, it is 1-8, More preferably, it is 1-3. Of the alkyl group, aryl group, and aralkyl group, an alkyl group is preferable. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group are preferable. A chain alkyl group such as a group, pentyl group, hexyl group, 2-ethylhexyl group, n-octyl group, lauryl group, stearyl group; cyclopropyl group, cyclobutyl group, cyclohexyl group, bicyclohexyl group, etc. An alkyl group; a group in which some or all of the hydrogen atoms of the chain alkyl group are substituted with a cycloalkyl group; a group in which some or all of the hydrogen atoms of the cycloalkyl group are substituted with chain alkyl groups; Etc. Of these, alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable from the viewpoint of further increasing the surface hardness. More preferably, it is a methyl group. From the viewpoint of increasing the refractive index, an aryl group or an aralkyl group is preferable, and a phenyl group is particularly preferable.
R ¹ may have a substituent, but is particularly preferably a group having no substituent.
In the present specification, the “alkyl group” includes not only a linear or branched alkyl group but also a cyclic alkyl group (cycloalkyl group).

The polysiloxane compound may be replaced with one having a group that forms a bond with an organic resin component (such as an epoxy compound or an oxetane compound) in place of R ¹ . For example, in the average composition formula (2), a compound having a curable functional group may be used instead of R ¹ . However, it is preferable not to use such a compound from the viewpoint of the stability of the organic resin component.

Y represents a condensed group or a condensed atom, and is bonded to Si to form the condensable group. Therefore, Y is preferably at least one selected from the group consisting of an OR group (R represents an alkyl group, an aryl group or an aralkyl group), a hydroxyl group, a halogen atom (X) and a hydrogen atom. is there. Suitable forms of R and X are as described above.

X, y, and z in the average composition formula (2) satisfy 0 <x <2, 0 <y <2, 1 <z <2, 0 <(x + y) <2, and x + y + 2z = 4 It is.
The above y represents the average value of the bonding ratio of Y to Si, and is a number exceeding 0 and less than 2. However, if y is 2 or more, there is a possibility that bubbles are generated in the molded body due to the condensation of Y. . Preferably it is less than 1, more preferably less than 0.5, particularly preferably less than 0.3. Moreover, it is preferable that it is a value larger than 0.001. If it is less than 0.001, the effect of improving the hardness due to the condensation of the polymetalloxane compound in the curing step becomes small, and the compatibility with the epoxy compound or the like becomes small. More preferred is a value greater than 0.01, even more preferred is a value greater than 0.05, and particularly preferred is a value greater than 0.08.

The z may be a number greater than 1 and less than 2. Preferably it is greater than 1.2 and less than 1.8, more preferably greater than 1.35 and less than 1.65.
The x + y may be a number greater than 0 and less than 2. Preferably it is more than 0.4 and less than 1.6, more preferably more than 0.7 and less than 1.3.
The x is preferably set as appropriate so that y and x + y satisfy the above-described preferable ranges.

The polymetalloxane compound may also contain other metals and inorganic elements as components from the viewpoint of controlling optical properties. Examples of the metal element include alkaline earth metal elements such as Be, Mg, Ca, Sr, Ba, and Ra; lanthanoid metal elements such as La and Ce; actinoid metal elements such as Ac; IIIa such as Sc and Y Group metal elements; Group IVa metal elements such as Ti, Zr and Hf; Group Va metal elements such as V, Nb and Ta; Group VIa metal elements such as Cr, Mo and W; Group VIIa metals such as Mn, Tc and Re Element; Group VIII metal element such as Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt; Group Ib metal element such as Cu, Ag, Au; Group IIb metal element such as Zn, Cd, Hg; Group IIIb metal elements such as Al, Ga, In, and Tl; Group IVb metal elements such as Ge, Sn, and Pb; Group Vb metal elements such as Sb and Bi; Group VIb metal elements such as Se and Te One of these It may be present together of two or more. These can be appropriately selected depending on the electrical characteristics, optical characteristics, magnetic characteristics and the like of the composition. For example, Ti, Zr, In, Zn, La, Al, etc. are preferable when it is desired to obtain a resin composition having a high refractive index among optical properties.

The metal oxide particles are preferably oxides in which M is at least one of Si, Ti, Zr, Zn, La, Y, and In, and the element is the main metal element. Specifically, at least one of silica, alumina, titania, zirconium oxide, zinc oxide, lanthanum oxide, yttrium oxide, and indium oxide is preferable.
From the viewpoint of enhancing the transparency of the cured product, the metal oxide particles preferably have an average primary particle size of 70 nm or less. More preferably, it is 30 nm or less. The average primary particle diameter is E. T.A. The specific surface area diameter calculated from the specific surface area measured by the method is adopted. The metal oxide particles are preferably dispersed as primary particles in the resin composition. As the average dispersed particle size, a volume-based average particle size obtained by light scattering particle size distribution measurement is adopted.
Thus, when improving transparency of hardened | cured material, a silica is especially suitable among the above.
On the other hand, from the viewpoint of increasing the refractive index of the cured product, titania, zirconium oxide, zinc oxide, lanthanum oxide, yttrium oxide, and indium oxide are preferable, and titania, zirconium oxide, and zinc oxide are more preferable.

As described above, M, which is the metalloxane component, is most preferably Si, that is, silicon, regardless of whether the metalloxane component is a polymetalloxane compound or metal oxide particles. Such a metalloxane component is excellent in compatibility or dispersibility in the resin composition, and since the refractive index is close to the refractive index of the epoxy-oxetane cured product, it has a high concentration without impairing transparency. Can be blended. As a result, the obtained cured product has a high hardness, and further, sink marks are sufficiently suppressed and the surface smoothness is excellent. Moreover, the transparency fall by metalloxane component addition can be suppressed.
On the other hand, from the viewpoint of increasing the refractive index of the cured product, M, Ti, Zr, Zn, In, La, and Y are suitable.

In the cationic curable resin composition for an optical lens, the content of the metalloxane component (metalloxane compound) is 10% by mass or more with respect to 100% by mass of the total amount of the cured product-forming component in the resin composition. Is preferred. When a polysiloxane compound is used as the metalloxane component, the content is more preferably 40% by mass or more with respect to 100% by mass of the total amount of the cured product-forming component in the resin composition. Thereby, generation | occurrence | production of sink marks of hardened | cured material can be suppressed further.
The content of the metalloxane component is preferably 60% by mass or less.

As the cation curing catalyst, as described above, it is preferable to use a photo cation curing catalyst or a thermal cation curing catalyst.
The photocationic curing catalyst is also called a photocationic polymerization initiator, and exhibits a substantial function as a curing agent when irradiated with light.
Examples of the photocation curing catalyst include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, p- (phenylthio) phenyldiphenylsulfonium hexafluoroantimonate, p- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate, 4-chlorophenyldiphenylsulfonium hexafluorophosphate, 4-chlorophenyldiphenylsulfonium hexafluoroantimonate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl Sulfide bishexafluoroantimonate, (2,4-cyclopentadien-1-yl) [(1 Methylethyl) benzene] -Fe- hexafluorophosphate, diaryliodonium hexafluoroantimonate and the like.

Specific examples of the above-mentioned photocationic curing catalyst include UVI-6950, UVI-6970, UVI-6974, UVI-6990 (manufactured by Union Carbide); Adekaoptomer SP-150, SP-151, SP- 170, SP-172 (manufactured by ADEKA); Irgacure 250 (manufactured by Ciba Japan); CI-2481, CI-2624, CI-2623, CI-2064 (manufactured by Nippon Soda); CD-1010, CD-1011, CD-1012 (manufactured by Sartomer); DTS-102, DTS-103, NAT-103, NDS-103, TPS-103, MDS-103, MPI-103, BBI-103 (manufactured by Midori Chemical); PCI-061T , PCl-062T, PCl-020T, PCl-022T (manufactured by Nippon Kayaku Co., Ltd.) CPI-100P, CPI-101A, CPI-200K (manufactured by Sun Apro); Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L, Sun-Aid ST-110L, Sun-Aid SI-145, Sun-Aid SI-150, Sun-Aid SI- Diazonium salt type, iodonium salt type, and sulfonium salt type such as 160, Sun-Aid SI-180L (manufactured by Sanshin Chemical Industry Co., Ltd.); WPAG series (manufactured by Wako Pure Chemical Industries, Ltd.) are preferred.

The thermal cation curing catalyst is also called a thermal acid generator, a thermal curing agent, a thermal cation generator, or a cationic polymerization initiator, and exhibits a substantial function as a curing agent when the curing temperature is reached in the adhesive composition. Is.
Examples of the thermal cation curing catalyst include the following general formula (3):
_{^{(R 3 a R 4 b R}} 5 c R 6 d Z) s + (AXt) s- (3)
(Wherein, Z represents at least one element selected from the group consisting of S, Se, Te, P, As, Sb, Bi, O, N and halogen elements. R ³ , R ⁴ , R ⁵ and R ⁶ is the same or different and represents an organic group, a, b, c and d are 0 or a positive number, and the sum of a, b, c and d is equal to the valence of Z. Cation (R ³ _a R ⁴ _b R ⁵ _c R ⁶ _d Z) ^{s +} represents an onium salt, A represents a metal element or metalloid which is a central atom of a halide complex, and B, P, As, Sb, And at least one selected from the group consisting of Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, and Co. X represents a halogen element, and s is a net charge of a halide complex ion. T is a halogen element in a halide complex ion The compound represented by this is preferred.

Specific examples of the anion (AXt) ^s- of the general formula (3) include tetrafluoroborate (BF ⁴⁻ ), hexafluorophosphate (PF ⁶⁻ ), hexafluoroantimonate (SbF ⁶⁻ ), hexafluoro arsenates ^{(AsF 6-),} hexachloroantimonate (SbCl ^6-), and the like.
Further formula AXt (OH) ^- anions may be used which is represented by. Other anions include perchlorate ion (ClO ₄ ⁻ ), trifluoromethyl sulfite ion (CF ₃ SO ₃ ⁻ ), fluorosulfonate ion (FSO ₃ ⁻ ), toluenesulfonate ion, and trinitrobenzenesulfone. An acid ion etc. are mentioned.

As the thermal cation curing catalyst, those capable of exhibiting a function as a curing agent at a relatively low temperature are suitable. Specifically, those that can be cured at 140 ° C. or lower are preferred. Thereby, while being able to suppress the curvature and the crack of a to-be-adhered body resulting from the difference in shrinkage | contraction rate of hardened | cured material and a to-be-adhered body, a to-be-adhered body has low heat resistance compared with inorganic materials, such as glass. Even if it consists of a resin material, the influence on the adherend due to heating in the thermosetting step can be reduced. More preferably, it functions as a curing agent at 120 ° C. or lower.

Specific examples of the thermal cation curing catalyst include diazonium salt types such as AMERICURE series (American Can), ULTRASET series (Adeka), and WPAG series (Wako Pure Chemical Industries); UVE Iodonium salt types such as series (manufactured by General Electric), FC series (manufactured by 3M), UV9310C (manufactured by GE Toshiba Silicone), Photoinitiator 2074 (manufactured by Rhone-Poulenc), WPI series (manufactured by Wako Pure Chemical Industries, Ltd.) CYRACURE series (manufactured by Union Carbide), UVI series (manufactured by General Electric), FC series (manufactured by 3M), CD series (manufactured by Sartomer), optomer SP series / optomer CP series (manufactured by Adeka) Aid SI series (Sanshin Chemical Industry Co., Ltd.), CI series (manufactured by Nippon Soda Co., Ltd.), WPAG series (manufactured by Wako Pure Chemical Industries, Ltd.), CPI series (manufactured by San-Apro Ltd.) sulfonium salt type or the like, and the like. Among these, a sulfonium salt type is preferable in that it can be cured at a relatively low temperature.

In the cation curable resin composition for an optical lens, the content of the cation curing catalyst is a non-volatile equivalent amount as an effective component amount not including a solvent or the like, and the total amount of the epoxy compound and the oxetane compound is 100% by mass. On the other hand, it is preferable to set it as 0.01-10 mass%.
By setting the content of the cationic curing catalyst in such a range, the curing rate can be more sufficiently increased. The content of the cationic curing catalyst is more preferably 0.05 to 5% by mass. More preferably, it is 0.1-3 mass%.

In photocuring, it is preferable to use a photosensitizer in combination with the photocationic curing catalyst. Examples of the photosensitizer include triethanolamine, methyldiethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and benzoic acid (2-dimethyl). Amines such as amino) ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, 2-dimethylhexyl 4-dimethylaminobenzoate, and the like are preferable.

It is preferable that the compounding quantity of the said photosensitizer is 0.1-20 mass% with respect to 100 mass% of total amounts of the said epoxy compound and oxetane compound. If it is less than 0.1% by mass, the photopolymerization may not proceed more efficiently, and if it exceeds 20% by mass, the ultraviolet ray may be prevented from being transmitted to the inside, and the curing may not be sufficient. . More preferably, it is 0.5-10 mass%.

In the cation curable resin composition for optical lenses, it is preferable not to use a volatile component such as a solvent as described above, but it can also be used as necessary. As the case where the resin composition contains a solvent, specifically, when the raw material used for the preparation of the resin composition contains a solvent, or when it is added separately for the purpose of adjusting the viscosity of the resin composition, etc. Can be mentioned. Examples of the solvent contained in the raw material used for the preparation of the resin composition include a solvent in a cationic curing catalyst solution and a dispersion medium in a dispersion of a metalloxane component (particularly metal oxide particles).
The solvent is not particularly limited and can be used as long as it is an organic solvent. However, a solvent that dissolves at least the above-described epoxy compound and oxetane compound is preferable. Moreover, when the said resin composition contains a metalloxane component, it is preferable that the said solvent melt | dissolves an epoxy compound and an oxetane compound, and can dissolve or disperse | distribute a metalloxane component. Specifically, for example, glycol ethers such as propylene glycol monomethyl ether, diethylene glycol acetate, propylene glycol monomethyl ether acetate, and ethylene glycol ethyl ether acetate; glycol derivatives such as glycol ester and glycol ether ester; methanol, ethanol, isopropanol Alcohols such as 1-butanol and cyclohexanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; ethers such as diethyl ether; carboxylic acid esters such as methyl acetate, ethyl acetate, butyl acetate and ethyl propionate.

The cationic curable resin composition for optical lenses may also contain a release agent as necessary. As the mold release agent, a normal mold release agent can be suitably used, but an alcohol having 8 to 36 carbon atoms, a carboxylic acid having 8 to 36 carbon atoms, a carboxylic acid anhydride having 8 to 36 carbon atoms, and a carbon number. It is preferably at least one compound selected from the group consisting of 8-36 carboxylic acid esters and C8-36 carboxylates. By including such a mold release agent, the mold can be easily peeled off when cured using a mold, and the appearance is controlled without damaging the surface of the cured product, thereby expressing transparency. Therefore, a cured product having more excellent transparency, surface appearance, dimensional accuracy, mold transferability and the like can be obtained, and the cured product is further useful for an optical lens or the like.

Among these compounds, more preferred are alcohols, carboxylic acids, and carboxylic acid esters, and even more preferred are carboxylic acids (particularly higher fatty acids) because the release effect can be sufficiently exhibited without inhibiting the cationic curing reaction. ) And carboxylic acid esters. In addition, since amines may inhibit a cation hardening reaction, it is preferable not to use as a mold release agent.
The above-mentioned compound may have any structure such as linear, branched or cyclic, and is preferably branched.
The number of carbon atoms of the compound is preferably an integer of 8 to 36, and thereby, a cured product exhibiting excellent peelability without impairing functions such as transparency and workability of the resin composition; Become. More preferably, it is 8-20 as carbon number, More preferably, it is 10-18.

As content of the said mold release agent, it is preferable that they are 0.01 mass% or more and 10 mass% or less with respect to 100 mass% of hardened | cured material formation components in the said cation curable resin composition for optical lenses. If it is less than 0.01% by mass, the effect of adding a release agent may be insufficient, and if it exceeds 10% by mass, the resin composition may be difficult to cure. More preferably, it is 0.1 mass% or more. The content of the release agent is more preferably 5% by mass or less, and further preferably 2% by mass or less.

The cationic curable resin composition for optical lenses has inorganic fine particles, a reactive diluent, and an unsaturated bond in addition to the above-described essential components and suitable components, as long as the effects of the present invention are not impaired. No saturated compounds, pigments, dyes, radical scavengers, antioxidants, UV absorbers, light stabilizers, plasticizers, non-reactive compounds, chain transfer agents, thermal polymerization initiators, anaerobic polymerization initiators, polymerization inhibitors, Adhesion improvers such as inorganic and organic fillers, coupling agents, heat stabilizers, antibacterial / antifungal agents, flame retardants, matting agents, antifoaming agents, leveling agents, wetting / dispersing agents, anti-settling agents Contains thickeners, anti-sagging agents, anti-coloring agents, emulsifiers, anti-slip / scratch agents, anti-skinning agents, drying agents, antifouling agents, antistatic agents, conductive agents (electrostatic aids), etc. May be.

The cationic curable resin composition for an optical lens preferably has a viscosity of 10,000 Pa · s or less. Thereby, it becomes more excellent in processing characteristics, and a cured product that is further excellent in dimensional accuracy, mold transferability, and the like can be obtained. More preferably, it is 1000 Pa.s or less, More preferably, it is 200 Pa.s or less. Moreover, it is preferable that it is 0.01 Pa.s or more. More preferably, it is 0.1 Pa · s or more, and further preferably 1 Pa · s or more.
The above-mentioned viscosity is measured using an R / S rheometer (manufactured by Brookfield, USA) for a resin composition before adding a cationic curing catalyst (curing agent), at 25 ° C. and at a rotational speed D = 1 / s. It is possible to do below. An RC25-1 measuring jig can be used at a viscosity of 20 Pa · s or higher, and an RC50-1 jig can be used at a viscosity of less than 20 Pa · s. Moreover, about the thing whose viscosity at the rotational speed D = 1 / s cannot be measured, the value of rotational speed D = 5-100 / s can be extrapolated and it can evaluate as a viscosity of a resin composition.

The present invention is also a cured product obtained by curing the cationic curable resin composition for optical lenses.
Since the cured product is obtained from the above-described cationic curable resin composition for optical lenses, the hygroscopic property is low, and stable performance can be exhibited even in a severe use environment.
As the curing method of the resin composition, various methods such as thermal curing and photocuring (curing by irradiation with active energy rays) can be suitably used. However, as described above, photocuring is possible because curing can be performed at a lower temperature. Is preferably adopted. As thermosetting, it is preferable to cure in a temperature range of about 30 to 400 ° C., and for photocuring, it is preferable to cure in the range where the irradiation light quantity is 10 to 10,000 mJ / cm ² . Curing may be performed in one stage, or may be performed in two stages such as primary curing (preliminary curing) and secondary curing (main curing). For example, when molding such as a lens is required, a demolding operation is required. However, a primary curing is performed before the demolding operation and a secondary curing is performed after the demolding operation. -A molding method is preferably employed.
Hereinafter, the case of performing the two-stage curing is described in detail.

As the two-step curing method, as the first step corresponding to the primary curing, the resin composition is photocured or thermally cured at 80 to 200 ° C., and the cured product obtained in the first step It is preferable to employ a method including a second step corresponding to secondary curing in which the material is thermally cured at a temperature exceeding 200 ° C. and not exceeding 500 ° C.

In the first step, it is preferable to perform photocuring. In this case, any active energy ray may be used as long as it can generate a cationic active species. For example, ionizing radiation such as ultraviolet rays, visible rays, electron beams, α rays, β rays, and γ rays, microwaves, high frequencies, infrared rays, laser beams, etc. are suitable, taking into consideration the absorption wavelength of the compound that generates the cationic active species. And may be selected as appropriate. Among these, ultraviolet rays or visible rays having a wavelength of 180 to 500 nm are preferable because they can be easily handled. Among these wavelength ranges, light having wavelengths of 254 nm, 308 nm, 313 nm, and 365 nm is particularly effective for curing.
In addition, the hardening process by the said active energy ray irradiation can be performed in air and / or an inert gas under any atmosphere under reduced pressure or under pressure.

Examples of the light generation source of ultraviolet light or visible light having a wavelength of 180 to 500 nm include, for example, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a chemical lamp, a black light lamp, a mercury-xenon lamp, an excimer lamp, Short arc lamps, helium / cadmium lasers, argon lasers, excimer lasers, sunlight and the like are suitable.

What is necessary is just to set suitably the irradiation time of the said active energy ray irradiation, ie, the hardening time in the hardening process by an active energy ray, according to the kind, irradiation amount, etc. of an active energy ray. For example, the irradiation time of ultraviolet rays or visible rays having a wavelength of 180 to 500 nm is preferably 0.1 microseconds to 30 minutes, and more preferably 0.1 milliseconds to 10 minutes.

When thermosetting is performed in the first step, the curing temperature is preferably 80 to 200 ° C. More preferably, it is 100 degreeC or more, More preferably, it is 160 degreeC or less.
The curing time in the thermosetting step is preferably, for example, within 10 minutes, more preferably within 5 minutes, and even more preferably within 3 minutes. Further, it is preferably 10 seconds or longer, more preferably 30 seconds or longer.

The thermosetting step can also be performed in air and / or under an inert gas atmosphere such as nitrogen under reduced pressure or under pressure. Moreover, you may change a curing temperature in steps within the range of 80-200 degreeC of curing temperature. For example, from the viewpoint of improving productivity, etc., the resin composition is held in the mold at a predetermined temperature and time, and then taken out of the mold and left in an inert gas atmosphere such as air and / or nitrogen for heat treatment. It is also possible to do. Moreover, you may combine photocuring (curing by active energy ray irradiation).

The first step is also preferably a curing step using a mold made of metal, ceramic, glass, resin or the like (referred to as “mold”). The curing process using a mold may be a curing process normally performed by a mold molding method such as an injection molding method, a compression molding method, a casting molding method, or a sandwich molding method. If it is a hardening process using such a metal mold | die, it is excellent in various physical properties, such as abrasion resistance, low shrinkage, dimensional accuracy, and mold transfer property, and there is no coloring and a transparent molded object (cured material). Easy to manufacture.

When the first step is a curing step using a mold, it is preferable to perform the demolding step after the first step and before the second step. The mold including the demolding process, that is, the cured product obtained in the first process is taken out from the mold, and the taken cured product is used for the next second process, whereby the expensive mold is effectively rotated (recycled). ) And the life of the mold can be extended, and a molded product can be obtained at low cost.
In this case, the resin composition is a one-component composition containing a curing agent and other components as necessary, and the one-component composition is filled into a mold that matches the shape of the target molded article (injection / A method in which the cured product is taken out from the mold after coating and the like is suitably used.

In the curing method, in the second step, the cured product obtained in the first step (preferably, the cured product taken out from the mold by the demolding step) is heat-cured at a temperature exceeding 200 ° C. and not more than 500 ° C. preferable. More preferably, it is 250 degreeC or more, More preferably, it is 300 degreeC or more, Most preferably, it is 330 degreeC or more, Most preferably, it is 350 degreeC or more. Moreover, More preferably, it is 400 degrees C or less.
The curing time in the second step is not particularly limited as long as the curing rate of the obtained molded body is sufficient, but considering the production efficiency, for example, it is preferably set to 30 minutes to 30 hours. . More preferably, it is 1 to 10 hours.

The second step can also be performed in any atmosphere of air and / or an inert gas atmosphere such as nitrogen. In particular, the second step is preferably performed in an atmosphere having a low oxygen concentration. For example, it is preferable to carry out in an inert gas atmosphere having an oxygen concentration of 10% by volume or less. More preferably, it is 3 volume% or less, More preferably, it is 1 volume% or less, Especially preferably, it is 0.5 volume% or less, Most preferably, it is 0.3 volume% or less. Further, the curing temperature may be changed stepwise within a temperature range exceeding 200 ° C. and not more than 500 ° C.

The strength of the cured product obtained by the above-described curing method may be a strength that can be taken out from the mold and keep the shape. For example, the shape change ratio when extruded with a force of 1 kgf / cm ² or more is 10%. The following compressive strength is preferred. The ratio of the shape change is more preferably 1% or less, still more preferably 0.1% or less, and particularly preferably 0.01% or less.

The cured product obtained by curing the cationic curable resin composition for an optical lens of the present invention preferably has a refractive index of 1.40 to 1.60. When the refractive index is in such a range, the cured product can be suitably used for an optical lens or the like. The refractive index of the cured product is more preferably 1.45 to 1.55, and still more preferably 1.47 to 1.53.
The refractive index can be measured using a refractometer (Atago Co., Ltd., DR-M2).

The cured product preferably has an Abbe number of 45 or more. Thereby, the wavelength dispersion of light can be reduced, the resolution can be increased, and the optical characteristics can be improved. If it is less than 45, for example, bleeding may be observed, sufficient optical characteristics may not be exhibited, and a material suitable for an optical lens may not be obtained. The Abbe number is more preferably 50 or more, still more preferably 55 or more, and particularly preferably 58 or more.
The Abbe number can be measured using a refractometer (Atago Co., Ltd., DR-M2).

The cured product is also preferably one having low hygroscopicity. Specifically, the moisture absorption rate (water absorption rate) is preferably less than 1.00%. Thereby, even under high-humidity conditions, a decrease in transparency due to moisture absorption of the cured product can be suppressed, and further, an effect of suppressing coloration due to heat or ultraviolet light and a decrease in transmittance of short wavelength light can be obtained. . As a result, when the cured product is applied to an optical lens, the optical characteristics are stabilized. The moisture absorption is more preferably 0.90% or less, still more preferably 0.70% or less, and particularly preferably 0.60% or less.
The moisture absorption rate is determined based on the amount of cured material immediately after curing (immediately after the end of the second curing step in two-stage curing) and the amount of cured material after a moist heat test (85 ° C., 85% RH, 100 hours). It can obtain | require by calculating the increase rate of the amount of hardening substances before and behind a test.

A cured product obtained by curing the cationic curable resin composition for an optical lens of the present invention has low hygroscopicity and can maintain excellent optical characteristics even in a severe use environment. Further, due to the resin composition having excellent moldability, the cured product has excellent mold transferability, and can be processed into a fine shape with high accuracy. Such a cured product can be suitably used for an optical member, for example. Among them, an eyeglass lens, a (digital) camera, a mobile phone, an in-vehicle camera, a camera imaging lens such as a surveillance camera, a light beam condensing, among others. It is extremely useful for optical lens applications such as lenses (optical pickup lenses) and light diffusion lenses such as LED lenses. The optical lens is preferably a camera lens, a light beam condensing lens, and a light diffusion lens, and more preferably a camera lens. Among camera lenses, imaging lenses such as an imaging lens for a mobile phone and an imaging lens for a digital camera are preferable. Moreover, it is preferable that it is a micro optical lens.
Thus, an optical lens using a cured product obtained by curing the resin composition is also one aspect of the present invention.

Since the cationic curable resin composition for optical lenses of the present invention has the above-described configuration, it has low hygroscopicity and can maintain excellent optical characteristics even in harsh usage environments. It is possible to obtain an optical lens having excellent properties. And the hardened | cured material obtained by hardening | curing the cationic curable resin composition for optical lenses of this invention can be used suitably as various optical lenses.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.

<Preparation of cationic curable resin composition for optical lens>
Production Example 1 (resin composition (1))
YX-8000 (trade name, hydrogenated bisphenol A type epoxy resin, weight average molecular weight of about 350, manufactured by Mitsubishi Chemical Corporation) as an epoxy compound in a four-necked flask equipped with a gas inlet, a condenser, and a stirring rod, and , OXT-221 as a oxetane compound (trade name, polyfunctional oxetane resin, di [1-ethyl (3-oxetanyl)] methyl ether, manufactured by Toagosei Co., Ltd.), PMSQ-E as a metalloxane compound (trade name, 50 parts of polymethylsilsesquioxane (manufactured by Konishi Chemical Co., Ltd.) was added and stirred well at 80 ° C. to make it uniform. After the liquid was cooled to 40 ° C., 0.8 part of CPI-101A (trade name, manufactured by San Apro) was added as a photocationic curing catalyst and mixed uniformly to obtain a resin composition (1).

Production Examples 2 to 14 (resin compositions (2) to (14))
Resin compositions (2) to (2) are prepared in the same manner as in Production Example 1 except that the types and blending amounts of epoxy compound, oxetane compound, metalloxane compound (if necessary) and photocationic curing catalyst are changed as shown in Table 1. 14) was obtained.

The viscosity of the resin composition before adding the curing agent (cationic curing catalyst) was measured by the following method. The results are shown in Table 1.
<Viscosity>
The measurement was performed using an R / S rheometer (manufactured by Brookfield, USA) under the conditions of 25 ° C. and rotation speed D = 1 / s. An RC25-1 measuring jig was used at a viscosity of 20 Pa · s or more, and an RC50-1 jig was used at a viscosity of less than 20 Pa · s.
Moreover, about the thing whose viscosity at the rotational speed D = 1 / s cannot be measured, the value of rotational speed D = 5-100 / s was extrapolated and evaluated as the viscosity of a resin composition.

<Creation of molded product (cured product)>
Examples 1-10, Comparative Examples 1-4
The resin composition prepared in the above production example (hereinafter also referred to as “prepared solution”) was subjected to vacuum defoaming treatment by applying heat at 50 ° C. as necessary. The mold is a silicon rubber sheet (made by Togawa Rubber Co., Ltd., thickness 1 mm, outer shape 50 mm ×) using two standard test plates (glass, manufactured by Nippon Test Panel, thickness 2 mm, size 50 mm × 50 mm) as a substrate. 50 mm, inner diameter 35 mm × 35 mm) was used as a spacer. The prepared solution is filled by removing one mold substrate, filling 2.5 g of resin into the hole of the silicone rubber sheet, pressing the removed substrate, and fixing with a spring-loaded clip. I took.
As a radiation irradiation light source, an exposure apparatus (basic configuration unit “ML-251B / D”), irradiation optical unit “PM25C-135” equipped with a 250 W ultra-high pressure mercury lamp (trade name “USH-250BY”, manufactured by USHIO INC.), USHIO INC. Was used. Irradiation was performed so that the illuminance on the substrate surface on the irradiation side of the mold was 33 mW / cm ² at a wavelength of 365 nm and the integrated light amount was ² J / cm ² .
The completed photocured molded body was taken out from the mold and heated at 250 ° C. for 1 hour in a vacuum atmosphere (post cure) to obtain a plate-shaped molded body having a thickness of 1 mm.

About the molded object obtained as mentioned above, refractive index, Abbe number, moisture absorption, and sink marks upon curing were measured and evaluated by the following methods. The results are shown in Table 1.
<Evaluation of refractive index and Abbe number>
The refractive index and Abbe number were measured in accordance with JIS K7142, and the following methods were used.
The refractive index was measured on the cured product (1 mm-thick molded product) using a refractometer (Atago Co., Ltd., DR-M2) at a measurement wavelength of 486 nm, 589 nm, and 656 nm at 20 ° C. . Table 1 shows the measured values at 589 nm.
The Abbe number was measured on the cured product (1 mm-thick molded body) using a refractometer (DR-M2 manufactured by Atago Co., Ltd.) at 20 ° C. In addition, 1-bromonaphthalene was used as a contact liquid for measurement.

<Hygroscopicity>
The hygroscopicity was calculated based on the following formula from the mass ratio of the amount of the cured substance immediately after post-curing at 250 ° C. and the amount of the cured substance after the moist heat test (85 ° C., 85%, 100 hours).
Moisture absorption (%) = (amount of cured material after wet heat test−amount of cured material immediately after post-curing at 250 ° C.) / Amount of cured material immediately after post-curing at 250 ° C. × 100

<Appearance when cured>
The curability and the appearance of the cured product were evaluated as follows.
○: No abnormality in the appearance of the cured product visually observed Sinking: Scratch in the appearance of the cured product visually defective curing: Uncured by radiation irradiation

Abbreviations and the like in Table 1 are as follows.
YX-8000: Hydrogenated bisphenol A type epoxy resin, weight average molecular weight of about 350, Mitsubishi Chemical Corporation YX-8040: Hydrogenated bisphenol A type epoxy resin, weight average molecular weight 3831, Mitsubishi Chemical Corporation CEL-2021P: Alicyclic Epoxy resin, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, OXT-221 manufactured by Daicel Chemical Industries, Ltd .: polyfunctional oxetane resin, di [1-ethyl (3-oxetanyl)] methyl ether OXT-212 manufactured by Toagosei Co., Ltd .: monofunctional oxetane resin, 2-ethylhexyl oxetane, PMSQ-E manufactured by Toagosei Co., Ltd., polymethylsilsesquioxane, PMPSQ-E manufactured by Konishi Chemical Industries, Ltd .: polymethylphenylsilsesquioxane , Konishi Chemical Industry Co., Ltd. CPI-101A: Triary A sulfonium salt-based photo cationic curing catalyst, manufactured by San-Apro Ltd.

From the examples and comparative examples, the following was found.
In Examples 1 to 10 using the cationic curable resin composition for an optical lens of the present invention, it is possible to sufficiently suppress the moisture absorption rate of the resulting cured product (can be less than 1.00%). all right. On the other hand, in Comparative Example 1 using only the hydrogenated epoxy compound as the cured product forming component, the moisture absorption rate of the cured product is not sufficiently low, and in Comparative Example 2 using only the oxetane compound as the cured product forming component, radiation irradiation is performed. It was found that it cannot be cured. Moreover, in the form which uses together a hydrogenated epoxy compound and another epoxy compound as an epoxy compound, the hydrogenated epoxy compound content in an epoxy compound was set to 60 mass% or more, and Examples 9 and 10 (each 62 mass%) And 78% by mass) can sufficiently suppress the moisture absorption rate, whereas in Comparative Examples 3 and 4 (0% by mass and 50% by mass), respectively, in which the hydrogenated epoxy compound content is less than 60% by mass, the moisture absorption rate is reduced. It turned out that it cannot suppress enough.

Claims (8)

A cationic curable resin composition for an optical lens comprising an epoxy compound, an oxetane compound and a cationic curing catalyst as essential components,
A cationic curable resin composition for optical lenses, wherein 60% by mass or more of 100% by mass of the total amount of the epoxy compound is a hydrogenated epoxy compound. 2. The cationic curable resin composition for an optical lens according to claim 1, wherein a mass ratio of the oxetane compound to a total amount of the epoxy compound is 1.0 or more. The cationic curable resin composition for an optical lens according to claim 1, wherein the oxetane compound is a polyfunctional oxetane compound. The total amount of the oxetane compound and the epoxy compound is 40% by mass or more with respect to 100% by mass of the total amount of the cured product-forming components in the cationic curable resin composition for optical lenses. The cation curable resin composition for optical lenses in any one of 1-3. The cation curable resin composition for an optical lens according to claim 1, wherein the cation curing catalyst is a photo cation curing catalyst. The cationic curable resin for an optical lens according to any one of claims 1 to 5, wherein a content of the solvent is 10% by mass or less with respect to a total amount of 100% by mass of the cationic curable resin composition for an optical lens. Composition. A cured product obtained by curing the cationic curable resin composition for an optical lens according to claim 1. An optical lens comprising the cured product according to claim 7.