JP6597060B2 - Curable resin composition, cured product, optical member, lens and camera module - Google Patents

Description

  The present invention relates to a curable resin composition, a cured product, an optical member, a lens, and a camera module.

  In recent years, in order to achieve surface mounting of a camera module, a resin lens having reflow resistance has been studied. As one of high refractive index lens materials having reflow resistance, curable compositions containing fluorene-based di (meth) acrylates have been studied.

  For example, Patent Document 1 discloses that a photosensitive composition containing a fluorene-based di (meth) acrylate, a (meth) acrylate having a biphenyl skeleton, a thioether compound, and a photopolymerization initiator is useful as a lens material for an image sensor. It is disclosed that there is. According to Patent Document 1, a molded product obtained by photocuring the composition can maintain a high transmittance even after reflow treatment.

  Patent Document 2 includes a curable compound containing at least one fluorene-based di (meth) acrylate, a vinyl group and a (meth) acryloyloxy group, having no fluorene ring, a thiol compound, and a radical polymerization initiator. It is disclosed that the composition is suitable as a material for an optical member such as an imaging lens. According to Patent Document 2, a cured resin obtained by curing the curable composition is hardly yellowed even under high temperature conditions such as soldering by a reflow method.

JP 2013-241554 A International Publication No. 2012/020659

  However, since the materials described in Patent Documents 1 and 2 are insufficient in suppressing yellowing caused by the reflow treatment, further improvement is required.

  The present invention has been made in view of the above circumstances, and the obtained cured product has high transparency, high refractive index, and high glass transition point, and a curable resin composition with little yellowing due to reflow treatment and the cured product thereof. An object of the present invention is to provide an optical member such as a lens including the cured product, and a camera module including the lens.

  The present invention includes the following [1] to [6].

  [1] A (meth) acrylate (A) having a fluorene skeleton represented by the following formula (1), a (meth) acrylic polymerizable monomer (B) other than the (meth) acrylate (A), at 23 ° C. A curable resin composition comprising a liquid organic sulfur compound (C), a phosphite compound (D) liquid at 23 ° C., and a polymerization initiator (E).

(In the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group, m represents an integer of 0 to 5, and n represents an integer of 0 to 5. .)

  [2] The total amount of the (meth) acrylate (A) and the (meth) acrylic polymerizable monomer (B) is 100% by mass, the (meth) acrylate (A) is 55 to 95% by mass, Curable resin composition as described in [1] whose said (meth) acrylic-type polymerizable monomer (B) is 5-45 mass%.

  [3] A cured product of the curable resin composition according to [1] or [2].

  [4] An optical member comprising the cured product according to [3].

  [5] A lens including the cured product according to [3].

  [6] A camera module including the lens according to [5].

  According to the present invention, the obtained cured product has high transparency, a high refractive index, and a high glass transition point, and a curable resin composition with little yellowing by reflow treatment, the cured product, and a lens including the cured product. Etc., and a camera module including the lens can be provided.

It is sectional drawing which shows one Embodiment of the camera module which concerns on this invention.

Hereinafter, the present invention will be described in detail. In the present invention, “(meth) acryl” is a general term for acrylic and methacrylic. “(Meth) acrylate” is a general term for acrylate and methacrylate. The “(meth) acryloyl group” is a general term for an acryloyl group and a methacryloyl group, and is represented by CH ₂ ═C (R) —C (═O) — (R represents a hydrogen atom or a methyl group).

[Curable resin composition]
The curable resin composition according to the present invention includes a (meth) acrylate (A) having a fluorene skeleton represented by the following formula (1) (hereinafter also referred to as component (A)), the (meth) acrylate (A). (Meth) acrylic polymerizable monomer (B) (hereinafter also referred to as (B) component), organic sulfur compound (C) which is liquid at 23 ° C. (hereinafter also referred to as (C) component), It contains a phosphite compound (D) that is liquid at 23 ° C. (hereinafter also referred to as component (D)), and a polymerization initiator (E) (hereinafter also referred to as component (E)).

In the formula (1), R ^1, the R ^2, R ³ and R ⁴ are each independently hydrogen atom or a methyl group, m represents an integer of 0 to 5, n is an integer of 0 to 5 .

  The curable resin composition according to the present invention may further contain other radical polymerizable monomer components.

((A) component)
The component (A) is a (meth) acrylate having a fluorene skeleton represented by the formula (1), and is a radical polymerizable monomer. (A) A component can raise the refractive index and glass transition point of hardened | cured material, and can reduce yellowing by a reflow process.

In the formula (1), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group. From the viewpoint of increasing the heat resistance stability of the cured product, R ¹ and R ⁴ are preferably hydrogen atoms. From the viewpoint of further increasing the refractive index of the cured product, R ² and R ³ are preferably hydrogen atoms. That is, R ¹ to R ⁴ are preferably all hydrogen atoms.

  In said Formula (1), m shows the integer of 0-5 and n shows the integer of 0-5. When m and n are integers of 5 or less, the refractive index and glass transition point of the cured product are increased. Since the viscosity of the curable resin composition is a value suitable for molding and the moldability is improved, m and n are each preferably an integer of 0 to 4, more preferably an integer of 1 to 3, and each of 1 to 2 The integer of is more preferable.

A commercial item can be used as (A) component. For example, R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms, and m and n are both 1 compounds, Ogsol EA-0200 (trade name, manufactured by Osaka Gas Chemical Co., Ltd.), And NK ester A-BPEF (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These may use 1 type and may use 2 or more types together.

  The content of component (A) is preferably 55 to 95% by mass, more preferably 60 to 90% by mass, with respect to 100% by mass of the total amount of component (A) and component (B). More preferably, it is 65-85 mass%, and it is especially preferable that it is 65-80 mass%. When content of (A) component is 55 mass% or more, the refractive index and glass transition point of hardened | cured material can be made high. Further, yellowing due to the reflow process can be reduced. Moreover, the viscosity of a curable resin composition can be made low because content of (A) component is 95 mass% or less.

((B) component)
The component (B) is a (meth) acrylic polymerizable monomer other than the component (A), and is a radical polymerizable monomer. The component (B) can have a viscosity suitable for molding the curable resin composition.

  Examples of the component (B) include monofunctional (meth) acrylic monomers and polyfunctional (meth) acrylic monomers other than the component (A).

  Specific examples of monofunctional (meth) acrylic monomers include (meth) acrylic acid, 2- (meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxyethyl maleate, 2- (meth) acryloyl phthalate (Meth) acrylic monomers containing carboxyl groups such as oxyethyl and hexahydrophthalic acid 2- (meth) acryloyloxyethyl; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl ( (Meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl ( Meta) Acrelay , N-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate and other alkyl (meth) acrylates; cyclohexyl (meth) Alicyclic structures such as acrylate, dicyclopentenyl (meth) acrylate, 2-dicyclopentenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, etc. Containing (meth) acrylic monomer: phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxy Liethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, phenoxypolypropylene glycol (meth) acrylate, phenylphenyl (meth) acrylate, phenylphenoxyethyl (meth) acrylate, phenoxybenzyl (meth) acrylate, phenylbenzyl (meth) ) Acrylate, naphthyl (meth) acrylate, (1-naphthyl) methyl (meth) acrylate and other (meth) acrylic monomers containing an aromatic ring structure; methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl ( Alkoxy (meth) acrylates such as meth) acrylate; Tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, etc. (Meth) acrylic monomer containing a ring structure; 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 2- (meth) acryloyloxyethyl acid phosphate, trifluoro Examples include ethyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and (meth) acryloylmorpholine. These monofunctional (meth) acrylic monomers may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the polyfunctional (meth) acrylic monomer include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di ( (Meth) acrylate, polybutylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedi Methanol di (meth) acrylate, polycarbonate diol di (meth) acrylate, polyester diol di (meth) acrylate, bisphenol A ethylene oxide adduct di (meth) acrylate, Sphenol A propylene oxide adduct di (meth) acrylate, bifunctional (meth) acrylate such as polyurethane di (meth) acrylate; trimethylolpropane tri (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, ε- Trifunctional (meth) acrylates such as caprolactone-modified tris ((meth) acryloxyethyl) isocyanurate; tetrafunctional (meth) acrylates such as ditrimethylolpropane tetra (meth) acrylate; dipentaerythritol penta (meth) acrylate And pentafunctional (meth) acrylates such as dipentaerythritol hexa (meth) acrylate. These polyfunctional (meth) acrylic monomers may be used individually by 1 type, and may use 2 or more types together.

  Among these, since the viscosity of the curable resin composition is a value suitable for molding and the moldability is improved, a monofunctional (meth) acrylic monomer is preferable. Moreover, the monofunctional (meth) acryl monomer containing an aromatic ring structure is more preferable from the point which can raise the refractive index of hardened | cured material. Furthermore, phenyl (meth) acrylate, benzyl (meth) acrylate, phenylphenyl (meth) acrylate, phenylphenoxyethyl (meth) acrylate, phenoxybenzyl (meth) acrylate, phenylbenzyl (meth) because of its high glass transition point More preferred are acrylates.

  The content of the component (B) is preferably 5 to 45% by mass, more preferably 10 to 40% by mass, with respect to 100% by mass of the total amount of the components (A) and (B). The content is more preferably 15 to 35% by mass, and particularly preferably 20 to 35% by mass. Since content of (B) component is 5 mass% or more, since content of (A) component decreases, the viscosity of curable resin composition can be made low. Moreover, since content of (A) component can be increased because content of (B) component is 45 mass% or less, the refractive index and glass transition point of hardened | cured material can be made high.

((C) component)
Component (C) is an organic sulfur compound that is liquid at 23 ° C. The component (C) can reduce yellowing due to the reflow treatment of the cured product. Moreover, since (C) component is a liquid at 23 degreeC, compatibility with (A) component and (B) component becomes favorable, and it can improve transparency of hardened | cured material. In addition, when an organic sulfur compound is 23 degreeC, it has fluidity | liquidity and an external appearance is transparent, it is judged that it is a liquid.

  Examples of the component (C) include dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dipentyl sulfide, dihexyl sulfide, ditridecyl thiodipropionate, bis [3- (dodecylthio) propanoic acid] thiobis [2- (1 , 1-dimethylethyl) -5-methyl-4,1-phenylene]; disulfide compounds such as dimethyl disulfide, diethyl disulfide, dipropyl disulfide, dibutyl disulfide, dipentyl disulfide, dihexyl disulfide; 1-butanethiol; 1-pentanethiol, 1-hexanethiol, 1-heptanethiol, 1-octanethiol, 1-nonanethiol, 1-decanethiol, 1-undecanethiol, 1-dodeca Monofunctional thiol compounds having one thiol group in the molecule such as thiol; 1,4-bis (3-mercaptopropionyloxy) butane, 1,4-bis (3-mercaptobutyryloxy) butane, tetraethylene glycol bis (3-mercaptopropionate), tetraethylene glycol bis (3-mercaptobutyrate), trimethylolethane tris (3-mercaptopropionate), trimethylolethane tris (3-mercaptobutyrate), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptobutyrate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, tris-[(3-mercaptobutyryloxy)- Ethyl] -iso Anurate, pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), dipentaerythritol hexakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptobutyrate) ) And the like, and polyfunctional thiol compounds having a plurality of thiol groups in the molecule. These (C) components may be used alone or in combination of two or more.

  Among these, a sulfide compound or a polyfunctional thiol compound is preferable because the glass transition point of the cured product can be increased. Moreover, since the transparency of hardened | cured material can be improved, a sulfide compound is more preferable. Further, dihexyl sulfide or ditridecyl thiodipropionate is more preferable because yellowing due to reflow treatment of the cured product can be particularly reduced.

  The content of the component (C) is preferably 0.05 to 5 parts by mass, and 0.1 to 3 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). Is more preferably 0.2 to 2 parts by mass, and particularly preferably 0.5 to 1.5 parts by mass. When content of (C) component is 0.05 mass part or more, yellowing by the reflow process of hardened | cured material can be decreased. Moreover, the refractive index and glass transition point of hardened | cured material can be made high because content of (C) component is 5 mass parts or less.

((D) component)
Component (D) is a phosphite compound that is liquid at 23 ° C. (D) component can reduce yellowing by the reflow process of hardened | cured material. Moreover, since (D) component is a liquid at 23 degreeC, compatibility with (A) component and (B) component becomes favorable, and it can improve the transparency of hardened | cured material. In addition, when a phosphite compound has fluidity | liquidity at 23 degreeC and an external appearance is transparent, it judges that it is a liquid.

  Examples of the component (D) include triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl hydrogen phosphite, tetraphenyl diphenyl Phosphite compounds having an aromatic ring structure such as propylene glycol diphosphite, tetra (C12-15 alkyl) -4,4′-isopropylidenediphenyl diphosphite; triethyl phosphite, tris (2-ethylhexyl) phosphite, tri Decyl phosphite, trilauryl phosphite, tris (tridecyl) phosphite, trioleyl phosphite, diethyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phospha DOO, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, bis (decyl) phosphite compound having no aromatic ring structure, such as pentaerythritol phosphite. These (D) components may be used individually by 1 type, and may use 2 or more types together.

  Among these, a phosphite compound having no aromatic ring structure is preferable because yellowing due to reflow treatment of the cured product can be particularly reduced. Moreover, since transparency of hardened | cured material can be improved, the phosphite compound which has the alkyl group which does not have an aromatic ring structure whose total carbon number of an alkyl group is 15-45 is more preferable. Furthermore, since the glass transition point of hardened | cured material can be made high, a tridecyl phosphite is still more preferable.

  The content of the component (D) is preferably 0.05 to 5 parts by mass, and 0.1 to 3 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). Is more preferably 0.2 to 2 parts by mass, and particularly preferably 0.5 to 1.5 parts by mass. When content of (D) component is 0.05 mass part or more, yellowing by the reflow process of hardened | cured material can be decreased. Moreover, the refractive index and glass transition point of hardened | cured material can be made high because content of (D) component is 5 mass parts or less.

((E) component)
Examples of the component (E) include radical polymerization initiators, such as photopolymerization initiators, thermal polymerization initiators, and peroxides used for redox polymerization. (E) The kind of component can be suitably selected according to the polymerization method.

  The photopolymerization initiator is a radical polymerization initiator used for photopolymerization. Specific examples of the photopolymerization initiator include benzophenone-type compounds such as benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, methylorthobenzoylbenzoate, 4-phenylbenzophenone; t-butylanthraquinone, 2-ethyl Anthraquinone type compounds such as anthraquinone; 2-hydroxy-2-methyl-1-phenylpropan-1-one, oligo {2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone}, Benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoin methyl ether, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-hydroxy-1- {4- [4- (2 -Hydroxy-2-methylpropi Nyl) benzyl] phenyl} -2-methylpropan-1-one, etc .; alkylphenone type compounds; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, diethylthioxanthone, isopropylthioxanthone, etc. 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl)- Examples include acylphosphine oxide type compounds such as phenylphosphine oxide; phenylglyoxylate type compounds such as phenylglyoxylic acid methyl ester. Among these, an alkylphenone type compound is preferable in that coloring of the cured product can be suppressed, and 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone are more preferable. Moreover, an acyl phosphine oxide type compound is preferable in that it can be sufficiently cured to the inside of the cured product, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide is more preferable in that coloring of the cured product can be suppressed. These photopolymerization initiators may be used alone or in combination of two or more.

  The thermal polymerization initiator is a radical polymerization initiator used for thermal polymerization. Examples of the thermal polymerization initiator include organic peroxides and azo compounds.

  Specific examples of the organic peroxide include ketone peroxides such as methyl ethyl ketone peroxide; 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t-hexyl) Peroxy) cyclohexane, 1,1-di (t-butylperoxy) cyclohexane and the like; 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide Hydroperoxides such as dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide; diacyl peroxides such as dilauroyl peroxide and dibenzoyl peroxide; di (4-t-butylcyclohexyl) peroxy Dicarbonate, di ( -Ethylhexyl) peroxydicarbonate such as peroxydicarbonate; t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxybenzoate, 1,1,3,3 -Peroxyesters such as tetramethylbutylperoxy-2-ethylhexanoate.

  Specific examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile). 1,1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, 4,4′-azobis-4-cyanovaleric acid, 2,2′-azobis- (2 -Amidinopropane) dihydrochloride and the like.

  These thermal polymerization initiators may be used alone or in combination of two or more.

  As the thermal polymerization initiator, an organic peroxide is preferable in that air bubbles hardly occur in the cured product. Considering the balance between curing time and pot life of the curable resin composition, the 10-hour half-life temperature of the organic peroxide is preferably 35 to 80 ° C, more preferably 40 to 75 ° C, and still more preferably 45. ~ 70 ° C. When the 10-hour half-life temperature is 35 ° C. or higher, the curable resin composition is hardly gelled at room temperature, and the pot life is improved. On the other hand, if the 10-hour half-life temperature is 80 ° C. or less, the curing time of the curable resin composition can be shortened. Examples of such organic peroxides include 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, di (4-t -Butylcyclohexyl) peroxydicarbonate and the like. As a commercially available product of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, for example, Perocta O (trade name, manufactured by NOF Corporation, 10 hour half-life temperature: 65.3 ° C.) Etc. Examples of commercially available products of t-butyl peroxy-2-ethylhexanoate include perbutyl O (trade name, manufactured by NOF Corporation, 10 hour half-life temperature: 72.1 ° C.). Examples of commercially available di (4-t-butylcyclohexyl) peroxydicarbonate include perroyl TCP (trade name, manufactured by NOF Corporation, 10 hour half-life temperature: 40.8 ° C.).

  Examples of the peroxide used for redox polymerization include dibenzoyl peroxide and hydroperoxide. These peroxides may be used alone or in combination of two or more.

In the redox polymerization, a redox polymerization initiator is usually used. The redox polymerization initiator is a polymerization initiator in which a peroxide and a reducing agent are used in combination. In the case where the above-described peroxide is used as a redox polymerization initiator, an example of a combination with a reducing agent is as follows.
(1) Dibenzoyl peroxide (peroxide) and aromatics such as N, N-dimethylaniline, N, N-dimethyl-p-toluidine, N, N-bis (2-hydroxypropyl) -p-toluidine Combination with tertiary amines (reducing agents).
(2) A combination of hydroperoxide (peroxide) and metal soap (reducing agent).
(3) A combination of hydroperoxide (peroxide) and thioureas (reducing agent).

  The content of the component (E) is preferably 0.01 to 10 parts by mass, and 0.05 to 5 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). Is more preferably 0.1 to 4 parts by mass, and particularly preferably 0.2 to 3 parts by mass. When content of (E) component is 0.01 mass part or more, sclerosis | hardenability of curable resin composition improves and it is easy to obtain hardened | cured material with a high glass transition point. Moreover, yellowing by the reflow process of hardened | cured material can be decreased because content of (E) component is 10 mass parts or less.

(Other radical polymerizable monomer components)
The other radical polymerizable monomer component is a radical polymerizable monomer other than the component (A) and the component (B). When the curable resin composition contains other radical polymerizable monomer components, the viscosity can be adjusted more easily. In addition, the glass transition point of the cured product is easily improved.

  Examples of other radical polymerizable monomer components include vinyl group-containing monomers other than (meth) acrylic monomers (hereinafter referred to as other vinyl group-containing monomers), silsesquioxane compounds having radical polymerizable groups, and the like. Is mentioned.

  Specific examples of the other vinyl group-containing monomers include aromatic vinyl monomers such as styrene and α-methylstyrene; vinyl cyanide monomers such as acrylonitrile; vinyl ester monomers such as vinyl acetate. These other vinyl group-containing monomers may be used alone or in combination of two or more.

  A silsesquioxane compound having a radically polymerizable group can be obtained, for example, by subjecting an alkoxysilane compound containing a trialkoxysilane compound having one radically polymerizable group in the molecule to a condensation reaction. Examples of trialkoxysilane compounds having one radical polymerizable group include 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, Vinyltriethoxysilane, vinyltriisopropoxysilane and the like can be mentioned. The (meth) acryloyl group is preferred as the radical polymerizable group from the viewpoint of excellent compatibility with the component (B) and copolymerizability. As the trialkoxysilane compound having one radical polymerizable group in the molecule, 3- (meth) acryloyloxypropyltrimethoxysilane and 3- (meth) acryloyloxypropyltriethoxysilane are preferable.

  Examples of commercially available silsesquioxane compounds having a radical polymerizable group include AC-SQTA-100, AC-SQSI-20, MAC-SQTM-100, and MAC-SQSI-20 (trade names, Toagosei Co., Ltd.) Company-made).

  These silsesquioxane compounds having a radical polymerizable group may be used alone or in combination of two or more.

  The content of the other radical polymerizable monomer component is preferably 15% by mass or less and more preferably 10% by mass or less in the total amount of 100% by mass of the radical polymerizable monomer component contained in the curable resin composition. 5 mass% or less is more preferable. As described above, the curable resin composition contains other radical polymerizable monomer components, which makes it easy to adjust the viscosity and the glass transition point of the cured product. As the content of increases, the refractive index of the cured product tends to decrease. If the content of the other radical polymerizable monomer component is 15% by mass or less in the total amount of 100% by mass of the radical polymerizable monomer component, the glass transition point is maintained while maintaining the refractive index of the cured product. It is easy to increase or adjust the viscosity of the curable resin composition to a value suitable for molding.

(Other ingredients)
The curable resin composition contains components other than the components (A) to (E) and the other radical polymerizable monomer components as long as the effects of the present invention are not impaired. Also good. Examples of other components include acrylic polymers, rubbers, phenolic antioxidants, silica particles, zirconia, plasticizers, ultraviolet absorbers, antifoaming agents, thixotropic agents, polymerization inhibitors, mold release agents, and fillers. , Phosphors, pigments and the like. These other components may be used individually by 1 type, and may use 2 or more types together.

(Method for producing curable resin composition)
As a method for producing the curable resin composition, for example, the components (A) to (E) and, if necessary, the other radical polymerizable monomer component and the other component are stirred and mixed at room temperature. And a method of heating and mixing them.

  When a thermal polymerization initiator is used as the component (E), from the viewpoint of the stability of the curable resin composition, the components (A) to (D) and, if necessary, the other radical polymerizable compounds. A method in which the monomer component and the other components are heated and mixed and then cooled, and the component (E) is added and stirred and mixed at room temperature to obtain a curable resin composition.

  In the case of producing a curable resin composition by heat mixing, it is preferable to mix under heating at 40 to 100 ° C. from the viewpoint of good compatibility and more uniform mixing. From the same viewpoint, the mixing stirring time is preferably 0.1 to 5 hours.

(Viscosity of curable resin composition)
The viscosity of the curable resin composition is preferably 100 to 50,000 mPa · s, more preferably 200 to 40,000 mPa · s, and still more preferably 500 to 30,000 mPa · s. If the viscosity of the curable resin composition is within the above range, good moldability can be obtained. In particular, when the viscosity of the curable resin composition is 100 mPa · s or more, resin leakage from a dispenser or a mold can be suppressed. Moreover, if this viscosity is 50,000 mPa * s or less, the penetration property to a metal mold | die and the workability | operativity at the time of liquid transfer will become favorable. The viscosity is a measured value obtained using a B-type viscometer at 23 ° C.

(Function and effect)
The curable resin composition according to the present invention described above includes the components (A) to (E). Therefore, the curable resin composition according to the present invention has a viscosity suitable for moldability. Moreover, by using the curable resin composition according to the present invention, a cured product having high transparency, refractive index, and glass transition point and less yellowing due to reflow treatment can be obtained.

[Cured product]
The cured product according to the present invention is a cured product of the curable resin composition according to the present invention described above.

  Examples of a method for obtaining a cured product include a method in which the curable resin composition according to the present invention is set in a predetermined shape and cured to obtain a cured product having a predetermined shape. As a method for obtaining a cured product having a predetermined shape in this way, for example, a coating method for applying a curable resin composition, a potting molding method, a casting molding method, a printing molding method, a liquid resin injection molding method (LIM). Method), transfer molding method and the like.

  In addition, as a method for curing the curable resin composition, any of photopolymerization, thermal polymerization, and redox polymerization can be employed depending on the type of the component (E) contained in the curable resin composition.

  In the case of obtaining a cured product by curing the curable resin composition by photopolymerization, the wavelength of light applied to the curable resin composition is not particularly limited, but it is preferable to irradiate ultraviolet rays having a wavelength of 200 to 400 nm. Specific examples of the ultraviolet light source include an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a high power metal halide lamp, and a UV-LED lamp.

  After photopolymerization of the curable resin composition, after-curing is preferably further performed. Thereby, the quantity of the unreacted (meth) acryloyl group which remains in hardened | cured material can be decreased, and the intensity | strength of hardened | cured material can be raised more. As conditions for the after cure, 0.1 to 24 hours are preferable at 70 to 150 ° C, and 0.2 to 10 hours are more preferable at 80 to 130 ° C.

  When the curable resin composition is cured by thermal polymerization to obtain a cured product, the curing conditions are not particularly limited, but the curing temperature is preferably 40 to 200 ° C. from the viewpoint of easily obtaining a cured product in which coloring is suppressed. 60 to 150 ° C. is more preferable.

  The curing time (heating time) in the case of molding by injecting the curable resin composition into a preheated mold as in the LIM method or the transfer molding method varies depending on the curing temperature. In the case of ° C., 1 to 180 seconds are preferable, 1 to 120 seconds are more preferable, and 1 to 60 seconds are more preferable. On the other hand, the curing time in the case of heating after injecting the curable resin composition into a normal temperature mold as in the casting molding method varies depending on the curing temperature, for example, 5 minutes to 5 hours when the curing temperature is 70 ° C. Is preferable, and 10 minutes to 3 hours is more preferable.

  After the curable resin composition is thermally polymerized, it is preferable to further perform after-curing. The after-curing conditions are preferably 0.1 to 10 hours at 50 to 150 ° C., and more preferably 0.2 to 5 hours at 70 to 130 ° C.

  When a curable resin composition is cured by redox polymerization to obtain a cured product, it can be cured at room temperature of 5 to 40 ° C. by using a redox polymerization initiator. The curing temperature is preferably 15 to 40 ° C. from the viewpoint that the amount of unreacted (meth) acryloyl groups remaining in the resulting cured product can be reduced and the strength of the cured product can be further increased.

  In addition, since the curable resin composition is difficult to gel and can be stably handled, there is a method in which a reducing agent is dissolved in the curable resin composition in advance and curing is performed by adding a peroxide thereto. preferable.

(Transparency of cured product)
Regarding the transparency of the cured product, when the thickness of the cured product is 1 mm, the total light transmittance is preferably 80% or more and the haze is 2% or less, the total light transmittance is 85% or more, and the haze is 1. More preferably, the total light transmittance is 90% or more and the haze is 1% or less. The total light transmittance and haze are values measured by the method described later.

(Refractive index of cured product)
About the refractive index of hardened | cured material, it is preferable that the measured value in the sodium D line | wire (589 nm) in 25 degreeC is 1.600 or more, It is more preferable that it is 1.605 or more, It is 1.610 or more Is more preferable. When the refractive index of the cured product is 1.600 or more, various optical designs are possible when applied to an optical member, and it can be applied to various uses. In addition, a refractive index is a value measured by the method mentioned later.

(Glass transition point of cured product)
The glass transition point of the cured product is preferably 90 ° C. or higher, more preferably 95 ° C. or higher, and further preferably 100 ° C. or higher. If the glass transition point of the cured product is 90 ° C. or higher, the shape of the cured product is stable even in a standard high-temperature and high-humidity test environment of 85 ° C. and 85% RH (that is, it is difficult to be deformed). When applied to the above, the reliability as an optical member is improved. In the present invention, the “glass transition point of the cured product” means the temperature at which the loss tangent (tan δ) shows the maximum value when the dynamic viscoelasticity and loss tangent of the cured product are measured with a dynamic viscoelasticity measuring device. It is. Specifically, the glass transition point of the cured product is a value measured by the method described later.

[Optical member]
The optical member according to the present invention includes a cured product of the curable resin composition according to the present invention. For example, the optical member is produced by molding the cured product. The molding may be performed after the curable resin composition is cured, or may be performed simultaneously with the curing. Examples of the molding method include a coating method, a potting molding method, a casting molding method, a printing molding method, a LIM method, and a transfer molding method. As a curing method at the time of molding, photopolymerization and thermal polymerization are preferable in that the transparency of the optical member becomes good.

  As an optical member, for example, a light emitting diode module, a mobile phone, a smartphone, a tablet terminal, a personal computer, a camera, an organic electroluminescence (organic EL) device, a flat panel display, a touch panel, electronic paper, a photodiode, a phototransistor, a solar cell, Examples thereof include films, sheets, lenses, optical waveguides, sealing materials, fillers, adhesives, reflective materials, pressure-sensitive adhesives, and wavelength conversion materials used for projectors and the like. Since the optical member according to the present invention has high transparency, high refractive index, and high glass transition point, it is particularly useful as a lens such as a camera lens. Further, since yellowing due to the reflow process is small, it is also useful as an optical member such as a lens that passes through the reflow process.

[lens]
The lens according to the present invention includes a cured product of the curable resin composition according to the present invention. The lens is used in, for example, a camera module provided in an electronic device such as a mobile phone, a smartphone, a tablet terminal, a personal computer, and a digital camera, a back camera of a car, a drive recorder, a driving support system, and the like.

  The lens according to the present invention may be a molded article made of the cured product according to the present invention, but is formed on a transparent substrate such as flat glass, curved glass or glass wafer, and on one or both surfaces of the transparent substrate. A hybrid lens comprising the cured product according to the present invention may be used.

  Examples of the method for molding the lens include a casting method in which the lens is obtained by curing the resin by heating or light irradiation after the curable resin composition is sandwiched between the upper and lower molds. Examples of the casting method include a method of molding lens pieces one by one, a wafer level method of cutting out lens pieces after molding a wafer to which a plurality of lens shapes are transferred.

[The camera module]
The camera module according to the present invention includes the lens according to the present invention.

  FIG. 1 shows a cross-sectional view of an example of a camera module according to the present invention. A camera module 100 shown in FIG. 1 includes a lens holder 2 including camera lenses 1a and 1b and an infrared cut filter 5 which are lenses according to the present invention, and a substrate 3 including a sensor chip 4 and bonding wires 6a and 6b. To do. A lens holder 2 is laminated on the substrate 3. Although the camera module 100 shown in FIG. 1 includes two camera lenses, the camera module may include one camera lens or three or more camera lenses. When there are a plurality of lenses, glass camera lenses may be mixed.

  Another example of the camera module is a camera module formed on a wafer by a wafer level method of dicing an adhesive laminate of a lens and an image sensor wafer.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these examples. In the examples and comparative examples, “part” means “part by mass”. Moreover, the total light transmittance, haze, refractive index, glass transition point, and heat-resistant yellowing in Examples and Comparative Examples were measured by the following methods.

<Measurement of total light transmittance and haze>
The total light transmittance and haze of a cured product having a diameter of about 50 mm and a thickness of about 1 mm were measured using a haze meter (trade name: HM-150, manufactured by Murakami Color Research Laboratory).

<Measurement of refractive index>
The refractive index (sodium D line (589 nm), 25 ° C.) of a cured product having a thickness of about 100 μm was measured with a multiwavelength Abbe refractometer (trade name: DR-M2, manufactured by Atago Co., Ltd.). Note that methylene sulfur iodide (manufactured by Atago Co., Ltd.) was used as the measurement intermediate solution.

<Measurement of glass transition point>
The dynamic viscoelasticity and loss tangent of the cured product of about 4 mm × 35 mm × thickness 1 mm were measured, and the temperature at which the loss tangent (tan δ) showed the maximum value was taken as the glass transition point of the cured product. For the measurement, a dynamic viscoelasticity measuring device (trade name: RSA-II, manufactured by TA Instruments Japan Co., Ltd.) was used. The measurement condition was a tensile mode. The measurement frequency was 10 Hz.

<Evaluation of heat-resistant yellowing>
After conducting a heat resistance test in which a cured product having a diameter of about 50 mm and a thickness of about 1 mm was stored at 260 ° C., the maximum temperature of reflow treatment, for 30 minutes, a spectrocolorimeter (trade name: CM-5, manufactured by Konica Minolta, Inc. ) To measure the b value of the cured product. As the measurement type, transmission measurement was selected. The heat yellowing was evaluated by the b value.

[ Reference Example 1]
<Preparation of curable resin composition>
In a reaction vessel equipped with a cooler, as the component (A), NK ester A-BPEF (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd., in the above formula (1), R ¹ , R ² , R ³ and R ⁴ 70 parts of a compound in which all are hydrogen atoms and n and m are both 1), 15 parts of benzyl methacrylate (trade name: Acryester BZ, manufactured by Mitsubishi Rayon) as component (B), and orthophenylphenoxyethyl acrylate (Trade name: MIRAMER M1142, manufactured by MIWON) 15 parts, (C) component as tritridecyl thiodipropionate (trade name: Adeka Stab AO-503, manufactured by ADEKA, liquid at 23 ° C.), and (D) component 1 part of tridecyl phosphite (trade name: Adeka Stub 3010, manufactured by ADEKA, liquid at 23 ° C.) and 1-H as component (E) B alkoxy phenyl ketone (trade name: of Irgacure 184, manufactured by BASF) was added and 2 parts. This was stirred at 70 ° C. for 2 hours to obtain a curable resin composition.

<Production of cured product>
The obtained curable resin composition was sandwiched between two glass plates using a 1 mm thick silicone sheet as a gasket, irradiated with ultraviolet light with an integrated light quantity of 3000 mJ / cm ² with a high-pressure mercury lamp, and then heated at 100 ° C. for 30 minutes. did. After cooling, the plate glass was removed to obtain a cured product having a diameter of about 50 mm and a thickness of about 1 mm used for measurement of total light transmittance and haze, and evaluation of heat-resistant yellowing. By using the same method, a 1 mm thick silicone sheet obtained by cutting out a rectangular shape of about 4 mm × 35 mm was used as a gasket to obtain a cured product of about 4 mm × 35 mm × 1 mm thickness used for measuring the glass transition point. Further, by using a polyester tape having a thickness of about 100 μm by the same method, a cured product having a thickness of about 100 μm used for measuring the refractive index was obtained.

  Using the obtained cured product, the total light transmittance, haze, refractive index, glass transition point and heat yellowing resistance were evaluated by the above-described methods. The results are shown in Table 1. The unit of each component in Table 1 is “part”.

[ Reference Examples 2-7 , 11-15 , Examples 8-10 , Comparative Examples 1-4]
A curable resin composition was prepared in the same manner as in Reference Example 1 except that the formulation shown in Table 1 was changed, and a cured product was prepared and evaluated. The results are shown in Table 1.

A-BPEF: a compound in which R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms and m and n are all 1 in the formula (1) (trade name: NK ester A-BPEF Manufactured by Shin-Nakamura Chemical Co., Ltd.)
・ BZMA: benzyl methacrylate (trade name: Acryester BZ, manufactured by Mitsubishi Rayon Co., Ltd.)
MIRAMER M1142: Orthophenylphenoxyethyl acrylate (trade name: MIRAMER M1142, manufactured by MIWON)
Adeka Stub AO-503: Ditridecyl thiodipropionate (trade name: Adeka Stub AO-503, manufactured by ADEKA, liquid at 23 ° C.)
1-decanethiol (trade name: 1-decanethiol, manufactured by Tokyo Chemical Industry Co., Ltd., liquid at 23 ° C.)
SFI-6R: Dihexyl sulfide (trade name: SFI-6R, manufactured by Daihachi Chemical Industry Co., Ltd., liquid at 23 ° C.)
Karenz MT PE1: pentaerythritol tetrakis (3-mercaptobutyrate) (trade name: Karenz MT PE1, manufactured by Showa Denko KK, liquid at 23 ° C.)
Adeka Stub 3010: Tridecyl Phosphite (trade name: Adeka Stub 3010, manufactured by ADEKA, liquid at 23 ° C.)
JP-308E: Tris (2-ethylhexyl) phosphite (trade name: JP-308E, manufactured by Johoku Chemical Industry Co., Ltd., liquid at 23 ° C.)
JP-318-O: trioleyl phosphite (trade name: JP-318-O, manufactured by Johoku Chemical Industry Co., Ltd., liquid at 23 ° C.)
Adeka Stub C: Diphenyl mono (2-ethylhexyl) phosphite (trade name: Adeka Stub C, manufactured by ADEKA, liquid at 23 ° C.)
JP-218-OR: Dioleyl hydrogen phosphite (trade name: JP-218-OR, manufactured by Johoku Chemical Industry Co., Ltd., liquid at 23 ° C.)
IRGACURE 184: 1-hydroxycyclohexyl phenyl ketone (trade name: IRGACURE 184, manufactured by BASF)
LUCIRIN TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name: LUCIRIN TPO, manufactured by BASF)
・ SUMILIZER GP: 6- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propoxy] butyldibenzo [d, f] [1,3,2] dioxaphosphine (trade name: SUMILIZER GP, manufactured by Sumitomo Chemical Co., Ltd., solid at 23 ° C.).

  From Table 1, the cured product produced using the curable resin composition obtained in each example has high transparency, refractive index and glass transition point, and yellowing in the heat resistance test is sufficiently small. It was. On the other hand, in Comparative Examples 1 to 3 that did not contain the component (C) or the component (D), they were greatly colored in the heat resistance test. Moreover, in Comparative Examples 3 and 4 containing a phosphite compound that was solid at 23 ° C., the transparency of the cured product was insufficient.

100 Camera module 1a, 1b Camera lens 2 Lens holder 3 Substrate 4 Sensor chip 5 Infrared cut filter 6a, 6b Bonding wire

Claims (6)

(Meth) acrylate (A) having a fluorene skeleton represented by the following formula (1), (meth) acrylic polymerizable monomer (B) other than the (meth) acrylate (A), monofunctional thiol, polyfunctional At least one organic sulfur compound (C) liquid at 23 ° C. selected from thiol, dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dipentyl sulfide and dihexyl sulfide , phosphite compound (D) liquid at 23 ° C., And a curable resin composition containing a polymerization initiator (E).

(In the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or a methyl group, m represents an integer of 0 to 5, and n represents an integer of 0 to 5. .)   The total amount of the (meth) acrylate (A) and the (meth) acrylic polymerizable monomer (B) is 100% by mass, and the (meth) acrylate (A) is 55 to 95% by mass. The curable resin composition according to claim 1, wherein the acrylic polymerizable monomer (B) is 5 to 45% by mass.   A cured product of the curable resin composition according to claim 1.   An optical member comprising the cured product according to claim 3.   A lens comprising the cured product according to claim 3.   A camera module including the lens according to claim 5.

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