Curable resin composition, adhesive, cured product, and camera module

Abstract

This invention provides a curable resin composition capable of forming a curable material with reduced surface gloss, and an encapsulation material comprising the curable resin composition. Furthermore, this invention provides a cured material obtained by curing the aforementioned curable resin composition or encapsulation material. Moreover, this invention further provides a camera module comprising the aforementioned cured material.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition, an adhesive comprising the curable resin composition, a cured product obtained by curing the curable resin composition, and a camera module comprising the cured product. [Previous Technology]

[0002] Adhesives that are temporarily cured by ultraviolet (UV) irradiation and formally cured by heating (hereinafter referred to as "UV-thermosetting adhesives") have been used in many fields, especially in semiconductor devices, particularly for camera module applications (see, for example, Patent Documents 1 and 2). Since the assembly of camera modules requires high-precision positioning of each component, the use of UV-thermosetting adhesives that can be temporarily fixed by temporary curing can improve manufacturing efficiency.

[0003] Regarding UV-curable adhesives, adhesives containing polyfunctional acrylate compounds and polyfunctional thiols are known. Such adhesives are cured by ene-thiol reaction (radical addition of a thiol group to the double bond in (meth)acryloxy), homopolymerization (radical polymerization of (meth)acryloxy), and Michael addition reaction (nucleophilic addition of a thiol group to the double bond in (meth)acryloxy).

[0004] Furthermore, suppressing glare is crucial for improving camera performance. Glare refers to the unintended reflection of incident light from the camera on the lens surface, lens body, or other parts within the camera, resulting in the inclusion of light that was not originally present in the captured image or video. [Prior Art Documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. WO2016 / 143815 [Patent Document 2] International Publication No. WO2016 / 143777 [Patent Document 3] Japanese Patent Application Publication No. 10-275964 [Summary of the Invention]

[0006] [Problem to be Solved by the Invention] As mentioned above, although adhesives are used in camera module manufacturing, the reflection of light from the hardened material formed by the adhesive curing process has historically been a negligible issue. However, in recent years, with the increasing size of CMOS image sensors, there is a tendency to place sensors closer to the hardened material. Furthermore, the demand for higher image quality photos and videos is gradually increasing. As a result, the reflection of light from the surface of the hardened material formed by the adhesive is becoming a problem. This problem is particularly pronounced in camera modules used in devices such as smartphones, tablets, and laptops.

[0007] While conventional UV-curable adhesives form a glossy cured surface, this is not currently a major issue. However, as mentioned above, the need to prevent glare and other problems in camera modules is gradually increasing, and there is a desire to improve the properties of UV-curable adhesives in order to reduce the gloss of the cured surface.

[0008] Patent Document 3 describes a flexible printed circuit board having an anti-reflective layer or film to prevent glare or ghosting caused by light leakage from the flexible printed circuit board used in signal transmission means within a camera; and a camera that uses a flexible printed circuit board with an anti-reflective layer or film to prevent reflection. However, from a manufacturing efficiency point of view, the method of attaching an anti-reflective film or the method of providing an anti-reflective layer are not desirable. Furthermore, Patent Document 3 describes an anti-reflective layer and film, but does not describe a liquid adhesive.

[0009] This invention was made in view of the problems described above. An object of this invention is to provide a curable resin composition that utilizes a novel mechanism to form a curable material with reduced surface gloss, and an encapsulation material comprising the curable resin composition. Another object of this invention is to provide a cured material obtained by curing the aforementioned curable resin composition or encapsulation material. Yet another object of this invention is to provide a camera module comprising the aforementioned cured material. [Means for Solving the Problems]

[0010] Under such circumstances, the inventors conducted in-depth research in order to develop a curable resin composition that forms a cured product with reduced surface gloss. Unexpectedly, they discovered that by using a curable resin composition containing only a specific amount of a thermosetting resin, such as epoxy resin, that reacts with a polyfunctional thiol compound and a compound having a (meth)acrylate group that reacts with the polyfunctional thiol compound, the surface gloss of the formed cured product can be significantly reduced. Based on the above novel insights, the present invention was finally completed.

[0011] That is, the present invention is not limited to the following, but includes the following inventions.

[0012] [1] A curable resin composition comprising the following (A) to (D): (A) a polyfunctional thiol compound; (B) a compound having a (meth)acrylate group; (C) a thermosetting resin having a functional group that can react with the aforementioned polyfunctional thiol compound (A) and not having a (meth)acrylate group; and (D) a photoradical initiator; wherein, [(C) mass of thermosetting resin] / ([(B) mass of compound having a (meth)acrylate group] + [(C) mass of thermosetting resin]) = 0.20 to 0.65. [2] The curable resin composition as described in paragraph 1 above, wherein, [(C) mass of thermosetting resin] / ([(B) mass of compound having a (meth)acrylate group] + [(C) mass of thermosetting resin]) = 0.30 to 0.60. [3] The curable resin composition as described in paragraph 1 or 2 above, wherein ([the total number of (meth)acrylate groups contained in the (B) compound having (meth)acrylate groups] + [the total number of functional groups in the (C) thermosetting resin that can react with (A) polyfunctional thiol compounds]) / [the total number of thiol groups contained in (A) polyfunctional thiol compounds] = 0.5 to 1.5. [4] The curable resin composition as described in any one of paragraphs 1 to 3 above, wherein (B) the compound having (meth)acrylate groups comprises a polyfunctional acrylate compound. [5] The curable resin composition as described in any one of paragraphs 1 to 4 above, wherein (C) the thermosetting resin comprises an epoxy resin. [6] The curable resin composition as described in any one of paragraphs 1 to 5 above, further comprising (E) a curing catalyst. [7] The curable resin composition as described in any one of paragraphs 1 to 6 above, further comprising (F) a pigment. [8] The curable resin composition as described in item 7 above, wherein (F) the pigment comprises a black pigment. [9] The curable resin composition as described in any one of items 1 to 8 above further comprises (G) a filler.

[10] The curable resin composition as described in any one of items 1 to 9 above forms a cured product whose specular gloss, measured at an incident angle of 60° according to JIS Z 8741, is 15% or less.

[11] The curable resin composition as described in any one of items 1 to 10 above is used in a camera module for attaching a support to a substrate, for attaching a lens barrel to a support, or for attaching an optical filter to a support.

[12] An adhesive comprising the curable resin composition as described in any one of items 1 to 11 above.

[13] A cured product is a cured product of the curable resin composition as described in any one of items 1 to 11 above or the adhesive as described in item 12 above.

[14] A camera module comprising the hardened material described in paragraph 13 above. [Effects of the Invention]

[0013] The curable resin composition of the present invention contains, in addition to a polyfunctional thiol compound and a compound having a (meth)acrylate group that reacts with the polyfunctional thiol compound, a specific amount of a thermosetting resin, such as an epoxy resin, that reacts with the former compound, other than the latter compound. Therefore, the curable resin composition of the present invention can form a cured product with reduced surface gloss. Such a curable resin composition is extremely useful in various semiconductor devices, particularly in the manufacture of camera modules, where there is a problem of light reflection on the surface of the formed cured product.

Implementation Method

[0015] The present invention will now be described in detail.

[0016] As described above, the curable resin composition of the present invention comprises the following as essential components: (A) a polyfunctional thiol compound; (B) a compound having a (meth)acrylate group; (C) a thermosetting resin having a functional group that can react with the aforementioned polyfunctional thiol compound (A) and not having a (meth)acrylate group; and (D) a photoradical initiator. These (A) to (D) are explained below.

[0017] Furthermore, in this specification, the term "resin" refers not only to polymers (especially synthetic polymers) but also to the molecules used to manufacture polymers before curing. For example, "epoxy resin" refers to materials containing monomers with epoxy groups before curing.

[0018] Furthermore, in this specification, the terms "acrylic acid" (or its derivatives) and "methacrylic acid" (or its derivatives) are used collectively, and sometimes the names "(meth)acrylic acid," "(meth)acrylate," "(meth)acrylic group," "(meth)acrylyl," etc., are used. These terms may be used as independent terms or as part of other terms. For example, the term "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid," and the term "(meth)acryloxy" means "acryloxy and / or methacryloxy."

[0019] In this specification, the term "camera" refers to an optical system equipped with lenses for connecting to a display and a device for optical imaging, the imaging wavelength range of which includes the visible light region, the infrared region, and the ultraviolet region. Therefore, "camera" includes not only cameras used in devices such as smartphones, tablets, or laptops that primarily capture images in the visible light region, but also cameras used in thermal imaging cameras or Time-of-Flight (ToF) devices for measuring distances to objects that detect wavelengths in the (near) infrared region. The application of a camera is not particularly limited; it can be used not only in devices such as smartphones, but also in vehicles, even for quantity / quality inspection in factories, or for surveillance inside and outside buildings. Furthermore, in this specification, the term "camera module" refers to a device that modularizes the main components of the aforementioned camera.

[0020] (A) Polyfunctional Thiol Compounds The curable resin composition of the present invention comprises at least one polyfunctional thiol compound. The polyfunctional thiol compound used in the present invention is only required to be a compound having two or more thiol groups, and is not particularly limited. Preferably, the polyfunctional thiol compound comprises a thiol compound having three or more thiol groups, more preferably a thiol compound having three thiol groups (trifunctional thiol compound) and / or a thiol compound having four thiol groups (tetrafunctional thiol compound). In one embodiment of the present invention, the polyfunctional thiol compound comprises a thiol compound having three thiol groups. In another embodiment of the present invention, the polyfunctional thiol compound comprises a thiol compound having four thiol groups. The thiol equivalent of the polyfunctional thiol compound is preferably 90 to 150 g / eq, and more preferably 90 to 140 g / eq.

[0021] In a certain embodiment of the present invention, from the viewpoint of improving the moisture resistance of the cured material, the aforementioned polyfunctional thiol compound is preferably a non-hydrolyzable polyfunctional thiol compound comprising a portion of the structure that does not have hydrolytic properties such as ester bonding. The non-hydrolyzable polyfunctional thiol compound will not undergo hydrolysis even under high temperature and high humidity conditions.

[0022] Examples of hydrolyzable polyfunctional thiols include trimethylolpropane 3-hydrothiopropylpropionate (manufactured by SC Organic Chemical Co., Ltd.: TMMP), 3-[(3-hydrothiopropylpropoxy)-ethyl]-triisocyanate (manufactured by SC Organic Chemical Co., Ltd.: TEMPIC), neopentyl tert-(3-hydrothiopropylpropionate) (manufactured by SC Organic Chemical Co., Ltd.: PEMP), tetraethylene glycol bis(3-hydrothiopropylpropionate) (manufactured by SC Organic Chemical Co., Ltd.: EGMP-4), dinepentyl tert-(3-hydrothiopropylpropionate) (manufactured by SC Organic Chemical Co., Ltd.: DPMP), neopentyl tert-(3-hydrothiobutyric acid) (manufactured by Showa Denko Co., Ltd.: KARENZ MT (registered trademark) PE1), 1,3,5-3-(3-hydrothiobutyric acid)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (manufactured by Showa Denko Co., Ltd.: KARENZ). MT (registered trademark) NR1, etc.

[0023] A preferred non-hydrolyzable polyfunctional thiol compound that can be used in this invention is a compound represented by the following formula (1): (wherein, R1 and R2 are independently selected from the group consisting of hydrogen atoms, alkyl groups having 1 to 12 carbon atoms, or phenyl groups, and R3, R4, R5, and R6 are independently selected from the group consisting of thiomethyl, thioethyl, and thiopropyl groups). In an example of a compound represented by formula (1), it comprises 1,3,4,6-tetra(2-thioethyl)ethynurea (trade name: TS-G, manufactured by Shikoku Chemical Industry Co., Ltd.), (1,3,4,6-tetra(3-thiopropyl)ethynurea (trade name: C3... TS-G (manufactured by Shikoku Chemical Industry Co., Ltd.), 1,3,4,6-tetra(hydrothiomethyl)acetylenurea, 1,3,4,6-tetra(hydrothiomethyl)-3a-methylacetylenurea, 1,3,4,6-tetra(2-hydrothioethyl)-3a-methylacetylenurea, 1,3,4,6-tetra(3-hydrothiopropyl)-3a-methylacetylenurea, 1,3,4,6-tetra(hydrothiomethyl)-3a,6a-dimethylacetylenurea, 1,3,4,6-tetra(2-hydrothioethyl ... (3-Hydrothiopropyl)-3a,6a-dimethylacetylurea, 1,3,4,6-tetra(hydrothiomethyl)-3a,6a-diphenylacetylurea, 1,3,4,6-tetra(2-hydrothioethyl)-3a,6a-diphenylacetylurea, 1,3,4,6-tetra(3-hydrothiopropyl)-3a,6a-diphenylacetylurea, etc. These can be used individually or in combination of two or more. Among these, 1,3,4,6-tetra(2-hydrothioethyl)acetylurea and 1,3,4,6-tetra(3-hydrothiopropyl)acetylurea are particularly preferred.

[0024] Another preferred non-hydrolyzable polyfunctional thiol compound that can be used in this invention is the compound shown in the following formula (2): (R8)mA-(R7-SH)n (2) (where A is a residue of a polyol having n+m hydroxyl groups and containing n+m oxygen atoms derived from the aforementioned hydroxyl groups, each R7 is independently an alkyl group having 1 to 10 carbon atoms, each R8 is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, m is an integer of 0 or more, n is an integer of 3 or more, and the aforementioned R7 and R8 are bonded to the aforementioned A by a separation of one of the aforementioned oxygen atoms) Two or more compounds shown in formula (2) can be used in combination. Examples of compounds shown in formula (2) include neopentyltetrol tripropanethiol (trade name: Multhiol Y-3, manufactured by SC Organic Chemical Co., Ltd.), neopentyltetrol tetrapropanethiol, etc. Among these, neopentyltetrol tripropanethiol is particularly preferred.

[0025] As a non-hydrolyzable polyfunctional thiol compound, it can also be used in polythiol compounds with more than two thioether bonds in the molecule that are trifunctional or more. Examples of such thiols include: 1,2,3-tris(hydrothiomethylthio)propane, 1,2,3-tris(2-hydrothioethylthio)propane, 1,2,3-tris(3-hydrothiopropylthio)propane, 4-hydrothiomethyl-1,8-dihydrothio-3,6-dithiaoctane, 5,7-dihydrothiomethyl-1,11-dihydrothio-3,6,9-trithiaundecane, 4,7-dihydrothiomethyl-1,11-dihydrothio-3,6,9-trithiaundecane, 4,8-dihydrothiomethyl-1,11-dihydrothio-3,6,9-trithiaundecane, tetra(hydrothiomethylthiomethyl)methane, tetra(2-hydrothioethylthiomethyl)methane, tetra(3-hydrothiomethylthiomethyl)methane, and tetra(3-hydrothiomethylthiomethyl)methane. (Thiopropylthiomethyl)methane, 1,1,3,3-Tetra(hydrothiomethylthio)propane, 1,1,2,2-Tetra(hydrothiomethylthio)ethane, 1,1,5,5-Tetra(hydrothiomethylthio)-3-thiapentane, 1,1,6,6-Tetra(hydrothiomethylthio)-3,4-dithiahexane, 2,2-bis(hydrothiomethylthio)ethanethiol, 3-hydrothiomethylthio-1,7-dihydrothio-2,6-dithiaheptane, 3,6-bis(hydrothiomethylthio)-1,9-dihydrothio-2,5,8-trithianonane, 3-hydrothiomethylthio-1,6-dihydrothio-2,5-dithiahexane, 1,1,9,9-Tetra(hydrothiomethylthio)-5-(3,3) -bis(hydrothiomethylthio)-1-thiapropyl)3,7-dithiononane, tris(2,2-bis(hydrothiomethylthio)ethyl)methane, tris(4,4-bis(hydrothiomethylthio)-2-thiabutyl)methane, tetra(2,2-bis(hydrothiomethylthio)ethyl)methane, tetra(4,4-bis(hydrothiomethylthio)-2-thiabutyl)methane, 3,5,9,11-tetra(hydrothiomethylthio)-1,13-dihydrothio-2,6,8,12-tetrathiatridecane, 3,5,9,11,15,17-tert-(hydrothiomethylthio)-1,19-dihydrothio-2,6,8,12,14,18-hexathianonadecane, 9-(2,2-bis(hydrothiomethylthio)ethyl)methane, tris(2,2-bis(hydrothiomethylthio)ethyl)methane, tris(4,4-bis(hydrothiomethylthio)-2-thiabutyl)methane, 3,5,9,11-tetra(hydrothiomethylthio)-1,19-dihydrothio-2,6,8,12,14,18-hexathianonadecane, 9-(2,2-bis(hydrothiomethylthio)ethyl)methane, tris ... Methylthio(ethyl)-3,5,13,15-tetra(hydrothiomethylthio)-1,17-dihydrothio-2,6,8,10,12,16-hexathiaheptadecane, 3,4,8,9-tetra(hydrothiomethylthio)-1,11-dihydrothio-2,5,7,10-tetrathiaheptadecane, 3,4,8,9,13,14-thio(hydrothiomethylthio)-1,16-dihydrothio-2,5,7,10,12,15-hexathiahexadecane, 8-[bis(hydrothiomethylthio)methyl]-3,4,12,13-tetra(hydrothiomethylthio)-1,15-dihydrothio-2,5,7,9,11,14-hexathiapentadecane, 4,6-bis[3,5-bis(hydrothiomethylthio)-7-hydrothio-2,6-dithiaheptylthio]-1,3-thiacyclohexane, 4-[3,5-bis(hydrothiomethylthio)-7-hydrothio-2,6-dithiaheptylthio]-6-hydrothiomethylthio-1,3-dithiacyclohexane, 1,1-bis[4-(6-hydrothiomethylthio)-1,3-dithiacyclohexylthio]-1,3-bis(hydrothiomethylthio)propane, 1-[4-(6-hydrothiomethylthio)-1,3-thiacyclohexylthio]-3-[2,2-bis(hydrothiomethylthio)ethyl]-7,9-bis(hydrothiomethylthio)-2,4,6,10-tetrathiaundecane, 3-[2-(1,3-dithiacyclobutane)]methyl-7, 9-Bis(dithiomethylthio)-1,11-dihydrothio-2,4,6,10-tetrathiaundecane (3-[2-(1,3-dithietanyl)]methyl-7,9-bis(mercaptomethylthio)-1,11-dimercapto-2,4,6,10-tetrathiaundecane), 9-[2-(1,3-dithietanyl)]methyl-3,5,13,15-tetra(dithiomethylthio)-1,17-dihydrothio-2,6,8,10,12,16-hexathieptagane, 3-[2-(1,3-dithietanyl)]methyl-7,9,13,15 -Aliphatic polythiols such as tetra(hydrothiomethylthio)-1,17-dihydrothio-2,4,6,10,12,16-hexathiaheptadecane; 4,6-bis[4-(6-hydrothiomethylthio)-1,3-thiacyclohexylthio]-6-[4-(6-hydrothiomethylthio)-1,3-thiacyclohexylthio]-1,3-thiacyclohexane, 4-[3,4,8,9-tetra(hydrothiomethylthio)-11-hydrothio-2,5,7,10-tetrathiaundecyl]-5-hydrothiomethylthio-1,3-dithiopentane, 4,5-bis[3,4-bis(hydrothiomethylthio)-6-hydrothio-2,5-dithiacyclohexylthio]-1,3-dithiopentane, 4-[3,4-bis(hydrothiomethylthio)-6-hydrothio-2,5-dithiacyclohexylthio]-1,3-dithiopentane, 4-[3,4-bis(hydrothiomethylthio)-6-hydrothio-2,5-dithiacyclohexylthio]-1,3-dithiopentane, 4-[3,4-bis(hydrothiomethylthio)-1,17-dihydrothio-2,4,6,10,12,16-hexathiaheptadecane ... [[3-bis(hydrothiomethylthio)methyl-5,6-bis(hydrothiomethylthio)-8-hydrothio-2,4,7-trithiaoctyl]-5-hydrothiomethylthio-1,3-dithiopentane, 2-{bis[3,4 ...6-hydrothio-2,5-dithio-2,4,7-trithiaoctyl]-5-hydrothiomethylthio-1,3-dithiopentane, 2-{bis[3,4-bis(hydrothiomethylthio)methyl-6-hydrothio-2,5-dithio-2,4,7-trithiaoctyl]-5-hydrothiomethylthio-1,3-dithiopentane, 2-{bis[3,4-bis(hydrothiomethylthio)methyl-6-hydrothio-2,5-dithio-2,4,7-dithio-2,4,7-dithiaoctyl]-5-hydrothiomethylthio-1,3-dithiopentane, 2-{bis[3,4-bis(hydrothiomethylthio)methyl-6-hydrothio-2,5-dithio-2,5-dithio-2,4,7-dithiaoctyl]-5-hydrothiomethylthio-1,3-dithiopentane, 2-{bis[3,4-bis(hydrothiomethylthio)methyl-6-hydrothio]-6-hydrothio-2,5-dithio-2,5-dithio-2,5-dithio-2,5-dithio-2,5-dithio-2,5-di [3,4-bis(hydrothiomethylthio)-6-hydrothio-2,5-dithiohexylthio]methyl-1,3-dithiohexacyclobutane, 2-[3,4,8,9-tetra(hydrothiomethylthio)-11-hydrothio-2,5,7,Polythiols with cyclic structures, such as [10-tetrathiaundecylthio]hydrothiomethylthiomethyl-1,3-dithiecyclobutane, 2-[3-bis(hydrothiomethylthio)methyl-5,6-bis(hydrothiomethylthio)-8-hydrothio-2,4,7-trithiaoctyl]hydrothiomethylthiomethyl-1,3-dithiecyclobutane, and 4-{1-[2-(1,3-dithiecyclobutyl)]-3-hydrothio-2-thiapropylthio}-5-[1,2-bis(hydrothiomethylthio)-4-hydrothio-3-thiabutylthio]-1,3-dithiopentane, etc., can be used alone or in combination of two or more.

[0026] (B) Compounds with (meth)acrylate groups The curable resin composition of the present invention comprises at least one compound with (meth)acrylate groups, that is, a compound having one or more hydroxyl groups esterified by one or more (meth)acrylate groups (which may have unesterified hydroxyl groups). However, the compounds with (meth)acrylate groups do not contain silane coupling agents with (meth)acrylate groups. Preferably, the compounds with (meth)acrylate groups do not contain silicon atoms. The compounds with (meth)acrylate groups used in the present invention may contain compounds having only one (meth)acrylate group, that is, monofunctional (meth)acrylate compounds, but preferably contain compounds having two or more (meth)acrylate groups, that is, polyfunctional (meth)acrylate compounds. In one embodiment of the present invention, the compounds with (meth)acrylate groups comprise polyfunctional (meth)acrylate compounds. Multifunctional (meth)acrylate compounds are preferably 2 to 4 functional, with 2-functional being more preferred. If the number of (meth)acrylate groups in a molecule becomes too large, the crosslinking density will be too high during temporary curing under UV irradiation, making the temporarily cured material difficult to deform during subsequent heat curing and potentially failing to adequately suppress glare. From the viewpoint of reducing the viscosity of the curable resin composition, the molecular weight of compounds containing (meth)acrylate groups is preferably 100 to 5000, with 200 to 3000 being more preferred. Compounds containing (meth)acrylate groups may also contain (meth)acrylic groups in a form other than (meth)acryloxy, provided that the above structural requirements are met.

[0027] Examples of compounds having a (meth)acrylate group include: di(meth)acrylate of bisphenol A (or its PEGylated form); di(meth)acrylate of dimethyloltricyclodecane; di(meth)acrylate of triisocyanate (2-hydroxyethyl); tri(meth)acrylate of triisocyanate (2-hydroxyethyl); tri(meth)acrylate of trimethylolpropane or its oligomers; poly(meth)acrylate of di(trimethylolpropane); tri(meth)acrylate of neopentyl tertrol or its oligomers; poly(meth)acrylate of dipentyl tertrol-polyester acrylate (multifunctional), etc.

[0028] Furthermore, other examples include: - poly(meth)acrylate of triisocyanate (acryloyloxyethyl)triisocyanate; - poly(meth)acrylate of caprolactone-modified triisocyanate (acryloyloxyethyl)triisocyanate; - poly(meth)acrylate of caprolactone-modified triisocyanate (methacryloyloxyethyl)triisocyanate; - poly(meth)acrylate of alkyl-modified dinepentylenetetrol; - poly(meth)acrylate of caprolactone-modified dinepentylenetetrol, etc. Examples of commercially available compounds having (meth)acrylate groups include polyester acrylate (trade name: ARONIX M-7100) manufactured by Toa Synthetic Co., Ltd., dimethyloltricyclodecane diacrylate (trade name: LIGHT ACRYLATE DCP-A) manufactured by Kyoei Chemical Co., Ltd., and polyester acrylate (trade name: EBECRYL 810) manufactured by Daicel Allnex Co., Ltd., etc. These compounds having (meth)acrylate groups can be used alone or in combination of two or more.

[0029] (C) Thermosetting Resin The thermosetting resin composition of the present invention comprises a thermosetting resin having functional groups that can react with the aforementioned polyfunctional thiol compounds (more precisely, the thiol groups therein), and not having (meth)acrylate groups. Hereinafter, functional groups that can react with thiol groups (but not (meth)acrylate groups) are sometimes referred to as "reactive functional groups". In addition to epoxy groups, reactive functional groups also include functional groups having double bonds such as maleimide groups, but in the present invention, epoxy groups are preferred as reactive functional groups. In one embodiment of the present invention, the thermosetting resin comprises an epoxy resin or a maleimide resin, preferably an epoxy resin.

[0030] Hereinafter, epoxy resins that can be used in the present invention will be described. Epoxy resins are generally classified into monofunctional epoxy resins and polyfunctional epoxy resins. In the present invention, it is preferred that the epoxy resin includes a polyfunctional epoxy resin. In a certain embodiment of the present invention, the epoxy resin includes both polyfunctional epoxy resins and monofunctional epoxy resins.

[0031] Monofunctional epoxy resins are epoxy resins containing one epoxy group. Examples of monofunctional epoxy resins include n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresol glycidyl ether, p-di-butylphenyl glycidyl ether, styrene oxide, α-pinene oxide, 4-tert-butylphenyl glycidyl ether, neodecanoic acid glycidyl ester, 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoic acid glycidyl ester, etc., but are not limited to these. These can be used alone or in combination of two or more.

[0032] Multifunctional epoxy resins are epoxy resins containing two or more epoxy groups. Multifunctional epoxy resins are broadly classified into aliphatic multifunctional epoxy resins and aromatic multifunctional epoxy resins. Aliphatic multifunctional epoxy resins are multifunctional epoxy resins with a structure that does not contain an aromatic ring. Examples of aliphatic multifunctional epoxy resins include: - Diepoxy resins made from (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, polytetramethylene ether glycol diglycidyl ether, glycerol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,2-epoxy-4-(2-methylepoxyethylene)-1-methylcyclohexane, cyclohexane-type diglycidyl ether, and dicyclopentadiene-type diglycidyl ether; - Triepoxy resins made from trimethylolpropane triglycidyl ether and glycerol triglycidyl ether. - Alicyclic epoxy resins such as vinyl(3,4-cyclohexene)dioxide and 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane; - Glycidylamine epoxy resins such as tetraglycidylbis(aminomethyl)cyclohexane; - Caprolactone epoxy resins such as 1,3-diglycidyl-5-methyl-5-ethylcaprolactone; and - epoxy resins with a polysiloxane backbone such as 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, etc., but not limited to these. These can be used alone or in combination of two or more.

[0033] Aromatic multifunctional epoxy resins are multifunctional epoxy resins that contain aromatic rings. This type is more commonly used in epoxy resins such as bisphenol A type epoxy resins. Examples of aromatic multifunctional epoxy resins include: - Bisphenol A type epoxy resins; - Branched multifunctional bisphenol A type epoxy resins such as p-glycidoxyphenyl dimethyl bisphenol A diglycidyl ether; - Bisphenol F type epoxy resins; - Phenolic varnish type epoxy resins; - Tetrabromobisphenol A type epoxy resins; - Fuchsia type epoxy resins; - Biphenyl aralkyl epoxy resins; - Diepoxy resins such as 1,4-phenyldiethanol diglycidyl ether; - Biphenyl type epoxy resins such as 3,3',5,5'-tetramethyl-4,4'-diglycidoxybiphenyl; - Glycidylamine type epoxy resins such as diglycidylaniline, diglycidyltoluidine, triglycidyl-p-aminophenol, tetraglycidyl-m-xylyldiamine; and - Epoxy resins containing naphthalene rings, etc., but not limited to these. These can be used alone or in combination of two or more. The epoxy equivalent of the epoxy resin is preferably 90 to 500 g / eq, more preferably 100 to 450 g / eq, and even more preferably 100 to 300 g / eq. Furthermore, the thermosetting resin does not contain silane coupling agents with reactive functional groups such as epoxy groups. Preferably, the thermosetting resin does not contain silicon atoms.

[0034] (D) Photoradical Initiator The curable resin composition of the present invention includes a photoradical initiator. By using a photoradical initiator, the curable resin composition of the present invention can be temporarily cured by UV irradiation. There are no particular limitations on the photoradical initiator that can be used in the present invention, and known ones may be used. Examples of photoradical initiators include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, diethoxyacetylbenzene, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, and benzyl... Benzophenone, benzoylbenzoic acid, methyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthones, 2-chlorothioxanthones, 2-methylthioxanthones, 2,4-dimethylthioxanthones, isopropylthioxanthones, 2,4-dichlorothioxanthones, 2,4-diethylthioxanthones, 2,4-diisopropylthioxanthones, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, methyl phenyl glyoxylate, phenylethylene glycol, camphorone, etc. These can be used alone or in combination of two or more. The amount of photoradical initiator is preferably 0.01 to 10% by mass of the curing resin composition, more preferably 0.05 to 5% by mass, and even more preferably 0.1 to 3% by mass.

[0035] In the curable resin composition of the present invention, the masses of the aforementioned (B) compound having (meth)acrylate groups and the aforementioned (C) thermosetting resin satisfy a predetermined relationship. Specifically, these masses satisfy the relationship shown in the following formula: [mass of (C) thermosetting resin] / ([mass of (B) compound having (meth)acrylate groups] + [mass of (C) thermosetting resin]) = 0.20 to 0.65. If the above ratio exceeds 0.65, the bonding strength after temporary curing by UV irradiation is insufficient. Furthermore, if the above ratio is less than 0.20, the surface gloss of the obtained cured product is not reduced. Moreover, when it is judged by visual inspection that the cured product has no surface gloss, a gloss meter is sometimes used to detect the gloss, and it is desirable that the specular gloss measured by the gloss meter is low. In this invention, from the viewpoint of simultaneously improving adhesion strength after temporary curing by UV irradiation and reducing the specular gloss of the resulting cured product, it is preferable that these masses satisfy the relationship shown in the following formula: [(C) mass of thermosetting resin] / ([(B) mass of compound having (meth)acrylate group] + [(C) mass of thermosetting resin]) = 0.30 to 0.60. The above ratio is more preferably 0.40 to 0.60.

[0036] In the curable resin composition of the present invention, it is preferable that the total number of thiol groups contained in the aforementioned (A) polyfunctional thiol compound, the total number of (meth)acrylate groups contained in the aforementioned (B) compound having (meth)acrylate groups, and the total number of functional groups (reactive functional groups) contained in the aforementioned (C) thermosetting resin that can react with (A) polyfunctional thiol compound satisfy a predetermined relationship. Specifically, it is preferable that ([the total number of (meth)acrylate groups contained in the aforementioned (B) compound having (meth)acrylate groups] + [the total number of functional groups contained in the aforementioned (C) thermosetting resin that can react with (A) polyfunctional thiol compound]) / [the total number of thiol groups contained in the aforementioned (A) polyfunctional thiol compound] = 0.5 to 1.5. This ratio is more preferably 0.6 to 1.4, and even more preferably 0.8 to 1.2. This relationship indicates that there are fewer unreacted (meth)acrylate groups, reactive functional groups, and thiol groups remaining directly in the cured product after the curing reaction. When there are fewer unreacted groups remaining in the cured product, it is difficult to form new crosslinks even when used in high-temperature environments, thus the physical properties of the cured product are stable.

[0037] (A) The total number of thiol groups contained in a polyfunctional thiol compound is the quotient obtained by dividing the mass (g) of the polyfunctional thiol compound contained in (A) by the thiol equivalent of that polyfunctional thiol compound. When multiple polyfunctional thiol compounds are contained, the total number of thiol groups is the sum of such quotients for each polyfunctional thiol compound. The thiol equivalent can be determined by iodine titration. This method is well known, for example, as disclosed in paragraph 0079 of Japanese Patent Application Publication No. 2012-153794. If the thiol equivalent cannot be determined by this method, the quotient can be calculated by dividing the molecular weight of the thiol compound by the number of thiol groups in one molecule of the thiol compound.

[0038] (B) The total number of (meth)acrylate groups in a compound having a (meth)acrylate group is the quotient obtained by dividing the mass (g) of the compound having a (meth)acrylate group in (B) by the (meth)acrylate equivalent of that compound. When a plurality of compounds having a (meth)acrylate group are contained, the total number of (meth)acrylate groups is the sum of the quotients for each of these compounds. The (meth)acrylate equivalent is calculated by dividing the molecular weight of the compound having a (meth)acrylate group by the number of (meth)acrylate groups in one molecule of that compound.

[0039] (C) The total number of reactive functional groups contained in the thermosetting resin is the quotient obtained by dividing the mass (g) of the thermosetting resin contained in (C) by the equivalent amount of reactive functional groups of the thermosetting resin (when there are multiple types of reactive functional groups, it is the sum of the quotients of each of the relevant reactive functional groups). When there are multiple types of thermosetting resins, the total number of reactive functional groups is the sum of the quotients of each of the relevant thermosetting resins.

[0040] When the reactive functional group is an epoxy group, the epoxy equivalent can be obtained according to the method described in JIS K7236. If the epoxy equivalent cannot be obtained by this method, the quotient can be calculated by dividing the molecular weight of the thermosetting resin by the number of epoxy groups in one molecule of the thermosetting resin. When the reactive functional group is a group other than an epoxy group, the total number of reactive functional groups can be easily determined by those skilled in the art.

[0041] The curable composition of the present invention may, if desired, contain any component other than (A) to (D) above, such as those described below.

[0042] ・Curing Catalyst The curable resin composition of the present invention may, if desired, contain a curing catalyst. The curing catalyst is used to cure the aforementioned thermosetting resin (C). By using a curing catalyst, the curable resin composition of the present invention can be cured at low temperatures for a short time. When the curable resin composition of the present invention contains a curing catalyst, the curing catalyst is not particularly limited as long as it can cure the aforementioned thermosetting resin (C), and known catalysts may be used.

[0043] For example, when (C) the thermosetting resin contains epoxy resin, a suitable curing catalyst selected from known epoxy resin curing catalysts can be used. Latent curing catalysts are preferred for epoxy resins. A latent curing catalyst is a compound that is inactive at room temperature but is activated by heating and functions as a curing catalyst. Examples of latent curing catalysts for epoxy resins include: imidazole compounds that are solid at room temperature; solid-dispersed amine adduct latent curing catalysts such as products of the reaction between amine compounds and epoxy compounds (amine-epoxy adduct systems); and products of the reaction between amine compounds and isocyanate compounds or urea compounds (urea-type adduct systems).

[0044] Representative examples of commercially available latent curing catalysts for epoxy resins include amine-epoxy adduct systems (amine adduct systems), such as "AMICURE PN-23" (Ajinomoto Fine-Techno Co., Ltd.), "AMICURE PN-40" (Ajinomoto Fine-Techno Co., Ltd.), "AMICURE PN-50" (Ajinomoto Fine-Techno Co., Ltd.), "NOVACURE HX-3742" (Asahi Kasei Co., Ltd.), "NOVACURE HX-3721" (Asahi Kasei Co., Ltd.), "NOVACURE HXA9322HP" (Asahi Kasei Co., Ltd.), "NOVACURE HXA3922HP" (Asahi Kasei Co., Ltd.), "NOVACURE HXA3932HP" (Asahi Kasei Co., Ltd.), "NOVACURE HXA5945HP" (Asahi Kasei Co., Ltd.), and "NOVACURE HXA9322HP" (Asahi Kasei Co., Ltd.). HXA9382HP (trade name of Asahi Kasei Corporation), FUJICURE FXR1121 (trade name of T&K TOKA Corporation), etc., and urea-type adduct systems such as FUJICURE FXE-1000 (trade name of T&K TOKA Corporation) and FUJICURE FXR-1030 (trade name of T&K TOKA Corporation), etc., but are not limited to these. The curing catalyst can be used alone or in combination of two or more. From the viewpoint of usable time and curing properties, solid-dispersed amine adduct latent curing catalysts are preferred.

[0045] Furthermore, in epoxy resin curing catalysts, there are those in the form of a dispersion of a multifunctional epoxy resin. When using such a curing catalyst, care should be taken to ensure that the amount of multifunctional epoxy resin in which the curing catalyst is dispersed is also included in the amount of epoxy resin, which is the aforementioned thermosetting resin in the curing resin composition of the present invention.

[0046] ・Pigment The curable resin composition of the present invention may include pigments if desired. By including pigments, the chromaticity of the curable resin composition of the present invention can be adjusted. By including pigments, the curable resin composition of the present invention can further reduce the unintended effects of light on the image sensor (camera element) within the camera module. There are no particular limitations on the pigment, but for example, black organic pigments, mixed organic pigments, carbon black, titanium black, and other inorganic pigments can be used. Examples of black organic pigments include perylene black and aniline black; examples of mixed organic pigments include those that are a mixture of at least two types of pigments selected from red, blue, green, purple, yellow, magenta, cyan, etc., to achieve a pseudo-black color; examples of inorganic pigments include graphite, and microparticles of metals and their oxides (including complex oxides), sulfides, nitrides, etc. Examples of metals include titanium, copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, silver, etc. In the curable resin composition of the present invention, pigments can be used alone or in combination of two or more. Furthermore, the pigment can be used in combination with other coloring agents such as dyes. In this invention, the pigment is preferably a black pigment, and more preferably a titanium black pigment. From the viewpoint of combining UV penetration and shielding properties, the average particle size of the primary particles of the pigment is preferably 20 to 200 nm, and more preferably 50 to 150 nm. In this specification, unless otherwise specified, the average particle size of the primary particles of the pigment refers to the median particle size (d50) of the volume standard determined by laser diffraction according to ISO-13320 (2009). When it is difficult to perform the measurement by laser diffraction (for example, when the object of measurement contains fine particles that are difficult to be measured by laser diffraction), the average particle size of the primary particles of the object of measurement can be determined by other measurement methods. Examples of other measurement methods include measurements performed by observation with a scanning electron microscope (SEM), dynamic light scattering, and calculation based on specific surface area. In this invention, it is preferable to calculate the average particle size of the primary particles of the test object from measurements performed by SEM observation.

[0047] • Filler The curable resin composition of the present invention may, if desired, contain a filler. When using the curable resin composition of the present invention as a single-component adhesive, the moisture resistance and thermal cycling resistance of the bonded site, especially the thermal cycling resistance, are improved by adding a filler. The thermal cycling resistance is improved by adding a filler because the coefficient of linear expansion of the cured material is reduced, that is, the expansion / contraction of the cured material caused by thermal cycling is suppressed.

[0048] The filler is not particularly limited as long as it has the effect of reducing the coefficient of linear expansion, and various fillers can be used. Specific examples of fillers include inorganic fillers such as silica fillers, alumina fillers, talc fillers, and calcium carbonate fillers, and organic fillers such as polytetrafluoroethylene (PTFE) fillers or acrylic polymer fillers. Among these, inorganic fillers, especially silica fillers, calcium carbonate fillers, or alumina fillers, are preferred, with silica fillers or calcium carbonate fillers being more preferred. Furthermore, the filler can be surface-treated with a surface treatment agent, such as a silane coupling agent (which may have substituents such as phenyl, vinyl, acrylonitrile, methacrylonitrile, etc.). In this invention, it is preferable that at least a portion of the filler is surface-treated.

[0049] The particle size distribution and average particle size of the filler are not particularly limited, but it is preferable to use a filler with an average particle size of 5.0 μm or less. An average particle size of 4.0 μm or less is preferred, and 3.0 μm or less is even more preferred. If the average particle size exceeds 5.0 μm, the depth of temporary curing by UV irradiation will decrease, making temporary curing difficult. There is no particular limitation on the lower limit of the average particle size. However, if the average particle size is less than 0.1 μm, the viscosity is prone to increase; therefore, 0.1 μm or more is preferred, and 0.2 μm or more is even more preferred. In a certain sample, the average particle size of the filler used in this invention is 0.1 μm or more and 5.0 μm or less, preferably 0.2 μm or more and 3.0 μm or less. In this specification, unless otherwise specified, the average particle size of the filler refers to the median particle size (d50) of the volume reference determined by laser diffraction according to ISO-13320 (2009). From the viewpoint of dispensing machine dispensing performance, the filler used in this invention is preferably spherical.

[0050] When the curable resin composition of the present invention contains a filler, the amount of filler relative to the curable resin composition as a whole is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 10 to 30% by mass.

[0051] ・Stabilizer The curable resin composition of the present invention may, if desired, contain a stabilizer. To improve its storage stability and extend its shelf life, a stabilizer may be added to the curable resin composition of the present invention. Various known stabilizers may be used as stabilizers for single-component adhesives, but from the perspective of improving storage stability, at least one is preferably selected from the group consisting of liquid borate ester compounds, aluminum chelates, and organic acids.

[0052] Examples of liquid borate ester compounds include 2,2'-oxobis(5,5'-dimethyl-1,3,2-oxaborcyclohexane), trimethylborate, triethylborate, tri-n-propylborate, triisopropylborate, tri-n-butylborate, tripentylborate, triallylborate, trihexylborate, tricyclohexylborate, trioctylborate, trinonylborate, tridecylborate, tri(dodecyl)borate, tri(hexadecyl)borate, tri(octadecyl)borate, tris(2-ethylhexoxy)borane, bis(1,4,7,10-tetraoxaundecyl)(1,4,7,10,13-pentaoxatetradecyl)(1,4,7-trioxaundecyl)borane, triphenylmethylborate, triphenylborate, tri-o-tolylborate, tri-m-tolylborate, triethanolamine borate, etc. Liquid borate ester compounds are preferred because they are liquid at room temperature (25°C), which can suppress the viscosity of the formulation to a lower level. Aluminum chelates, for example, Alumichelate A (manufactured by Kawakami Fine Chemical Co., Ltd.). Organic acids, for example, barbituric acid.

[0053] When the curable resin composition of the present invention contains a stabilizer, the amount of stabilizer is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the total mass of components (A) to (D), more preferably 0.05 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass.

[0054] ・Coupling Agent The curable resin composition of the present invention may, if desired, include a coupling agent. From the viewpoint of improving adhesion strength, it is preferable to add a coupling agent, especially a silane coupling agent. A silane coupling agent is an organosilicone compound having two or more different functional groups in its molecule, including a functional group that can chemically bond with inorganic materials and a functional group that can chemically bond with organic materials. Generally, the functional group that can chemically bond with inorganic materials is a hydrolyzable silica group, and silica groups containing alkoxy groups, especially methoxy and / or ethoxy groups, are used as such functional groups. The functional groups that can chemically bond with organic materials are vinyl, epoxy, (meth)acrylate, styrene, unsubstituted or substituted amine, hydrogen sulfide, urea, isocyanate, etc. Various silane coupling agents having the aforementioned functional groups can be used as coupling agents. Specific examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-hydrothiopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate propyltriethoxysilane, etc. These silane coupling agents can be used alone or in combination of two or more. In this invention, even if the silane coupling agent (including those used in the surface treatment of the above-mentioned fillers) has reactive functional groups such as (meth)acrylic or epoxy groups, it is not included in components (A) to (D).

[0055] In the curable resin composition of the present invention, from the viewpoint of improving adhesion strength, the amount of coupling agent is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the total mass of components (A) to (D), and more preferably 0.1 to 5 parts by mass.

[0056] ・Rhythmic Agent The curable resin composition of the present invention may, if desired, include a rhythmic agent. There are no particular limitations on the rhythmic agents that can be used in the present invention, and those known may be used. Examples of rhythmic agents used in the present invention include silica, bentonite, calcium carbonate, etc., but are not limited to these. In the present invention, it is preferred that the rhythmic agent includes silica. Silica may be natural silica (silica, quartz, etc.) or synthetic silica. Synthetic silica can be synthesized by any method including dry and wet methods. Furthermore, the rhythmic agent may be surface-treated with a surface treatment agent (e.g., polydimethylsiloxane). In the present invention, it is preferred that at least a portion of the rhythmic agent is surface-treated. The average particle size of the primary particles of the rhythmic agent is preferably 5 to 50 nm.

[0057] Relative to the total weight of the curing resin composition, the curing resin composition of the present invention preferably contains 0.1 to 30% by weight of a hygroscopic agent, more preferably 1 to 20% by weight, and particularly preferably 1 to 10% by weight.

[0058] ・Other Additives If desired, the curable resin composition of the present invention may contain other additives, such as ion traps, leveling agents, antioxidants, defoamers, flame retardants, solvents, etc., without prejudice to the intent of the invention. The types and amounts of each additive are as commonly used.

[0059] The method for manufacturing the curable resin composition of the present invention is not particularly limited. For example, components (A) to (D) and other desired additives are simultaneously or separately introduced into a suitable mixer, and mixed by heating while melting and stirring as needed to form a homogeneous composition, thereby obtaining the curable resin composition of the present invention. The mixer is not particularly limited, but a pounder, Henschel mixer, three-roll mill, ball mill, planetary mixer, bead mill, etc., equipped with a stirring device and a heating device can be used. Furthermore, these devices can be used in appropriate combinations.

[0060] As described above, the curable resin composition obtained in this manner can be converted into a final cured product by applying a two-stage curing process including the following treatments: • temporary curing treatment by ultraviolet (UV) irradiation and • formal curing treatment by heating.

[0061] The temporary curing treatment can be carried out at room temperature by irradiating the curable resin composition of the present invention with a sufficient cumulative amount of ultraviolet light. The irradiation intensity is preferably 100 to 10000 mW / cm², more preferably 1000 to 9000 mW / cm². The wavelength of the ultraviolet light is preferably 315 to 450 nm, more preferably 340 to 430 nm, and particularly preferably 350 to 380 nm. The light source for the ultraviolet light is not particularly limited, and high-pressure mercury lamps, metal halide lamps, gallium nitride-based UV-LEDs, etc., can be used. The cumulative amount of ultraviolet light irradiated by the curable resin composition of the present invention is preferably 200 mJ / cm² or more, more preferably 500 mJ / cm² or more, even more preferably 1000 mJ / cm² or more, and particularly preferably 2000 mJ / cm² or more. There is no particular upper limit to the cumulative amount of light, and it can be freely set within the scope of not impairing the intent of the present invention. The cumulative light intensity of ultraviolet light can be measured using measuring instruments commonly used in this field, such as ultraviolet cumulative light intensity meters and light receivers. For example, the cumulative light intensity in the wavelength region (310 to 390 nm) of ultraviolet light with a center wavelength of 365 nm can be measured using an ultraviolet cumulative light intensity meter (USHIO Electric Co., Ltd., UIT-250) and a light receiver (USHIO Electric Co., Ltd., UVD-S365).

[0062] On the other hand, the formal curing process can be carried out by heating the temporarily cured resin composition of the present invention under appropriate conditions. This heating is preferably carried out at 60 to 120°C, more preferably at 60 to 100°C, and particularly preferably at 70 to 90°C. Furthermore, this heating is preferably carried out for 5 to 180 minutes, more preferably for 10 to 120 minutes, and particularly preferably for 20 to 70 minutes.

[0063] When the curable resin composition of the present invention is subjected to the above-described temporary curing and formal curing treatments, a cured product with reduced surface gloss can be formed. The reduction in gloss is due to the presence of a structure with fine bumps on the surface of the cured product, which causes the reflection to become mainly diffuse reflection when irradiated by light, thus reducing specular reflection. An example of such a fine bump structure is shown in FIG. 4. It is inferred that the mechanism for generating this fine bump structure is that when the curable resin composition of the present invention is subjected to a temporary curing treatment, a portion of the (C) thermosetting resin that has not participated in the curing reaction is formed as a fine discontinuous phase (corresponding to the white area in FIG. 4 after curing) dispersed in the continuous phase (corresponding to the black area in FIG. 4 after curing), and appears on the surface of the resin composition. Then, during the formal curing treatment, this portion (discontinuous phase) hardens to form a surface with fine bumps. Therefore, assemblies using the curable resin composition of the present invention to join its components solve the problem caused by specular reflection of light. For example, camera modules manufactured using the curable resin composition of the present invention can significantly suppress glare during shooting.

[0064] In this invention, the gloss of the object surface can be evaluated according to JIS Z 8741 by measuring the specular gloss at an incident angle of 60°. The specular gloss of the cured product of the curable resin composition of this invention is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less.

[0065] The curable resin composition of the present invention can be used as an adhesive or encapsulating material. Specifically, the resin composition of the present invention can be used for bonding and encapsulating components for camera modules. For example, in the manufacture of a camera module, as shown in FIG1, the curable resin composition of the present invention can be used for bonding the support 70 and the substrate 20. Furthermore, the curable resin composition of the present invention can be used for bonding the lens barrel 60 and the support 70. Also, the curable resin composition of the present invention can be used for bonding the optical filter 50 and the support 70. A pneumatic dispensing machine or the like can be used when supplying the resin composition to the bonding surfaces.

[0066] Furthermore, in this invention, a curable resin composition of the present invention is also provided for attaching a support 70 to a substrate 20, for attaching a lens barrel 60 to a support 70, or for attaching an optical filter 50 to a support 70.

[0067] The curable resin composition of the present invention can be used, for example, as an adhesive or raw material for bonding semiconductor devices containing various electronic components (especially those where suppressing light reflection is important) or components constituting electronic components to each other.

[0068] In this invention, an adhesive comprising the curable resin composition of the present invention is also provided. The adhesive of the present invention is, for example, suitable for fixing components constituting a camera module. In one embodiment of the present invention, the curable resin composition or adhesive of the present invention is used to suppress glare during shooting. In another embodiment of the present invention, a curable resin composition or adhesive of the present invention is also provided for forming a cured material having a fine protrusion structure on its surface. Furthermore, in this invention, a cured material obtained by curing the curable resin composition or adhesive of the present invention is also provided. In this invention, a camera module comprising the cured material of the present invention is also provided. [Examples]

[0069] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto. Furthermore, in the following examples, parts and % refer to parts by mass and percentage by mass unless otherwise specified.

[0070] Examples 1 to 13 and Comparative Examples 1 to 3: Curable resin compositions were prepared by mixing predetermined amounts of the components using a three-roll mill according to the formulations shown in Table 1. In Table 1, the amount of each component is expressed in parts by mass (unit: g).

[0071] (A) Polyfunctional thiols In the examples and comparative examples, the compounds used as (A) polyfunctional thiols are as follows: (A-1): Neopentyl tetrakis(3-hydrothiopropionate) (trade name: PEMP, manufactured by SC Organic Chemicals Co., Ltd., thiol equivalent: 122) (A-2): Neopentyl tetrakis tripropanethiol (trade name: Multhiol Y-3, manufactured by SC Organic Chemicals Co., Ltd., thiol equivalent: 140)

[0072] (B) Compounds having (meth)acrylate groups In the examples and comparative examples, the compounds used as (B) compounds having (meth)acrylate groups are as follows: (B-1): Polyfunctional acrylate compound 1 (trade name: ARONIX M-7100, manufactured by Toa Synthetic Co., Ltd., (meth)acrylate equivalent: 188) (B-2): Polyfunctional acrylate compound 2 (trade name: LIGHT ACRYLATE DCP-A, manufactured by Kyoei Chemical Co., Ltd., (meth)acrylate equivalent: 152)

[0073] (C) Thermosetting Resin In the examples and comparative examples, the compounds used as (C) thermosetting resins are as follows: (C-1): Bisphenol F type epoxy resin / bisphenol A type epoxy resin mixture (trade name: EXA-835LV, manufactured by DIC Corporation, epoxy equivalent: 165) (C-2): Bisphenol A type epoxy resin (trade name: jER834, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 250)

[0074] (D) Photoradical Initiator In the examples and comparative examples, the compounds used as (D) photoradical initiators are as follows: (D-1)2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one (trade names: Omnirad 907, manufactured by IGM Resins BV)

[0075] (E) Curing Catalyst In the examples and comparative examples, the compounds used as (E) curing catalysts are as follows: (E-1) Amine-epoxy adduct latent curing catalyst (trade name: NOVACURE HXA9322HP, manufactured by Asahi Kasei Corporation) (E-2) Imidazole latent curing catalyst (trade name: FUJICURE FXR1121, manufactured by T&K TOKA Corporation)

[0076] The aforementioned latent curing catalyst (E-1) is used in the form of a dispersion (latent curing catalyst / mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin (epoxy equivalent: 170)) formed by dispersing the latent curing catalyst in microparticle form in epoxy resin (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin = 1 / 2 (mass ratio)). The epoxy resin constituting this dispersion is considered to be a part of the thermosetting resin (C). Therefore, in Table 1, the amount of the latent curing catalyst in (E-1) is expressed separately in the column of (E) curing catalyst, and the amount of epoxy resin in (E-1) is expressed in the column of (C) thermosetting resin.

[0077] (F) In the examples and comparative examples, the compounds used as pigments (F) are as follows: (F-1) Titanium black (trade name: 13M, manufactured by Mitsubishi MATERIAL Electronics Chemical Co., Ltd.) (F-2) Carbon black (trade name: BLACK 4, manufactured by ORION ENGINEERED CARBONS Co., Ltd.)

[0078] (G) Filler In the examples and comparative examples, the compounds used as filler (G) are as follows: (G-1) Spherical silicon dioxide (trade name: SE5200SEE, manufactured by ADMATECHS Co., Ltd., average particle size: 2 μm) (G-2) Calcium carbonate (trade name: CS4NA, manufactured by Ube MATERIALS Co., Ltd., average particle size: <0.5 μm)

[0079] (Evaluation of the glossiness of the hardened surface) The curable resin composition was printed into a 15mm × 50mm (0.3mm thick) rectangle using a stencil on a 25mm × 75mm × 1.5mm glass plate. Using an EXCELITAS TECHNOLOGIES AC475 UV LED irradiation device, with a cumulative light dose of 2000mJ / cm² (measured using a USHIO Electric Co., Ltd. UIT-250 (connected to a UVD-365 receiver), the printed curable resin composition was temporarily cured by UV irradiation. Then, the temporarily cured curable resin composition was formally cured at 80°C in a blower dryer for 60 minutes. The resulting cured material on the glass plate was used as a test piece. The test piece, placed 1m below two 32W fluorescent lamps at an angle of approximately 30° to the glass plate surface, was visually observed to evaluate the glossiness of the test piece surface. The results are shown in Table 1.

[0080] (Evaluation of the specular gloss of the hardened surface) Using a GLOSS CHECKER IG-331 (light source: LED (wavelength 890nm)) manufactured by Horiba Manufacturing Co., Ltd., the specular gloss (%) of the test piece surface, which was the same as that used in the above-mentioned "Evaluation of the presence or absence of gloss on the hardened surface", was measured under the conditions of 60° incident angle and 60° received angle, in accordance with JIS Z 8741. The results are shown in Table 1.

[0081] (Evaluation of Adhesion Strength Due to Temporary Hardening by UV Irradiation) A curable resin composition was printed into a 2mm φ circle on a 3cm × 4cm × 0.3mm stainless steel (SUS304) plate using a stencil. The printed composition was 2mm φ and 0.13mm thick. Alumina wafers of 1.5mm × 3mm × 0.5mm were placed on the printed curable resin composition. Using an EXCELITAS TECHNOLOGIES AC475 UV LED irradiation device with a cumulative light dose of 2000mJ / cm2 (measured using a USHIO Electric Co., Ltd. UIT-250 (connected to a UVD-365 receiver)), the printed curable resin composition was temporarily hardened by UV irradiation, allowing the alumina wafers to adhere to the stainless steel plate. The shear strength (in N) of each bonded area was measured using a benchtop universal testing machine (AIKOH ENGINEERING Co., Ltd. 1605HTP). The shear strength of each component is the average of multiple (n=10) measurements. The results are shown in Table 1. The adhesion strength produced by temporary curing by UV irradiation is preferably 2.5 N or higher, and even better if it is 5 N or higher.

[0082] [Table 1-1]

[0083] [Table 1-2]

[0084] (Observation of the surface of the hardened material) A photograph showing the appearance of hardened material A, obtained using the curing resin composition of Example 4 as the curing resin composition and in accordance with the method described in "Evaluation of the glossiness of the surface of the hardened material" above, is shown in Figure 2. Furthermore, a photograph showing the appearance of hardened material B, obtained in the same manner as described above except using the curing resin composition of Comparative Example 1, is shown in Figure 3. Additionally, an optical microscope photograph of the surface of hardened material A is shown in Figure 4, and an optical microscope photograph of the surface of hardened material B is shown in Figure 5. Both Figures 4 and 5 were taken at 20x magnification using an objective lens, and their width (horizontal length) is approximately 0.7 mm.

[0085] The curable resin composition of the present invention can form a cured product with sufficient adhesive strength after temporary curing and reduced surface gloss. In contrast, curable resin compositions outside the scope of the present invention form cured products with insufficient adhesive strength or insufficient reduction in surface gloss after temporary curing. Furthermore, when the surfaces of cured product A of the embodiment and cured product B of the comparative example are observed under a microscope, their surfaces are not completely flat. However, compared to the latter, the former has an intentionally and significantly raised structure. Therefore, it is considered that the cured product of the embodiment intentionally reduces specular gloss, while the cured product of the comparative example does not sufficiently reduce specular gloss. [Industrial Applicability]

[0086] The curable resin composition of the present invention, in addition to a polyfunctional thiol compound and a compound having a (meth)acrylate group that reacts with the polyfunctional thiol compound, also contains only a specific amount of a thermosetting resin, such as an epoxy resin, that reacts with the former compound, other than the latter compound. Therefore, the curable resin composition of the present invention can form a cured object with reduced surface gloss. Such a curable resin composition is extremely useful in the manufacture of various semiconductor devices, especially camera modules, where there is a problem of light reflection on the surface of the formed cured object. [Simplified Explanation of the Diagram]

[0014] Figure 1 is an example of a cross-sectional view of a camera module. Figure 2 is a photograph showing the appearance of cured product A obtained by curing the curable resin composition of Example 4. Figure 3 is a photograph showing the appearance of cured product B obtained by curing the curable resin composition of Comparative Example 1. Figure 4 is an optical microscope photograph (objective lens magnification: 20x) of the surface of cured product A obtained by curing the curable resin composition of Example 4. Figure 5 is an optical microscope photograph (objective lens magnification: 20x) of the surface of cured product B obtained by curing the curable resin composition of Comparative Example 1.

Claims

1. A curable resin composition comprising (A) to (D) and (F): (A) a polyfunctional thiol compound; (B) a compound having a (meth)acrylate group; (C) a thermosetting resin having a functional group capable of reacting with the aforementioned polyfunctional thiol compound (A) and not having a (meth)acrylate group; (D) a photoradical initiator; and (F) a pigment; wherein, [(C) mass of thermosetting resin] / ([(B) mass of compounds having (meth)acrylate groups] + [(C) mass of thermosetting resin]) = 0.20 to 0.65, ([(B) total number of (meth)acrylate groups in compounds having (meth)acrylate groups] + [(C) total number of functional groups in thermosetting resin that can react with (A) polyfunctional thiol compounds]) / [(A) total number of thiol groups in polyfunctional thiol compounds] = 0.5 to 1.

5.

2. The curable resin composition as described in claim 1, wherein, [(C) Mass of thermosetting resin] / ([(B) Mass of compound having (meth)acrylate group] + [(C) Mass of thermosetting resin]) = 0.30 to 0.

60.

3. The curable resin composition as described in claim 1 or 2, wherein, (B) Compounds having (meth)acrylate groups include polyfunctional acrylate compounds.

4. The curable resin composition as described in claim 1 or 2, wherein, (C) Thermosetting resins include epoxy resins.

5. The curing resin composition as described in claim 1 or 2 further comprises (E) a curing catalyst.

6. The curable resin composition as described in claim 1, wherein, (F) The pigment contains black pigment.

7. The curable resin composition as described in claim 1 or 2 forms a cured product whose specular gloss is 15% or less when measured at an incident angle of 60° in accordance with JIS Z 8741.

8. The curable resin composition as described in claim 1 or 2 is used in a camera module for attaching a support to a substrate, attaching a lens barrel to a support, or attaching an optical filter to a support.

9. An adhesive comprising a curable resin composition as described in any one of claims 1 to 8.

10. A cured compound, which is a cured compound of the curable resin composition described in any one of claims 1 to 8 or the adhesive described in claim 9.

11. A camera module comprising the hardened material described in claim 10.

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