Curable composition

Abstract

The object of the present invention is to provide a curable composition having both excellent photocurability and excellent thermal curability, low viscosity, and small curing shrinkage. The solution of the present invention is a curable composition comprising the following components (1) to (4): (1) a compound having a (meth)acryloyl group, (2) a polythiol compound having two or more mercapto groups in one molecule, (3) a photoradical generator, and (4) a latent curing agent, wherein the above-mentioned component (1) comprises component (1-1): (1-1) a compound having a poly(oxyalkylene) chain and a (meth)acryloyl equivalent of 300 or more.

Description

Technical Field

[0001] The present invention relates to curable compositions. Background Art

[0002] In recent years, as the functionality of portable devices such as smartphones has increased, the pixel count of camera modules installed in smartphones and other portable devices has continued to increase. In addition, as camera modules become smaller and more functional, the positional accuracy of lenses and image sensors, for example, has become very important.

[0003] On the other hand, in order to avoid thermal damage caused by high-temperature treatment of image sensors, etc., the adhesive used for the assembly of camera modules is required to have low-temperature curing properties. In addition, from the perspective of improving production efficiency, it is also required to have the performance of curing at low temperatures and in a short time (low-temperature-short-time curing properties). From this point of view, as low-temperature-short-time curing adhesives, most of them use ultraviolet curing adhesives and thermosetting epoxy resin adhesives (such as patent documents 1 and 2). However, on the other hand, the ultraviolet curing adhesive can cure quickly, but the curing shrinkage is large, and the position of the parts is offset (misalignment) after curing. On the other hand, as for thermosetting epoxy resin adhesives, although they are low-temperature-short-time curing adhesives, in order to maintain the bonding posture during bonding, the bonded parts must be fixed with a clamp or device. In addition, due to the increase in temperature caused by heating, the viscosity decreases, and there is a possibility of positional offset of the parts, which may not be satisfactory.

[0004] Therefore, in order to solve the above-mentioned problems, several adhesives have been proposed. The adhesives are a type of adhesive that is used to temporarily fix the components that constitute the camera module by curing (pre-curing) caused by irradiation with light (ultraviolet light, visible light) and to bond (formally fix) by curing (formal curing) caused by heat (for example, Patent Documents 3 and 4).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-140497

[0008] Patent Document 2: Japanese Patent Application Publication No. 2013-88525

[0009] Patent Document 3: Japanese Patent Application Publication No. 2009-51954

[0010] Patent Document 4: Japanese Patent Application Publication No. 2009-79216. Summary of the invention

[0011] Problems to be solved by the invention

[0012] Even when using a light- and heat-curable adhesive as described in Patent Documents 3 and 4, if the curing shrinkage of the adhesive is still large, there is a problem of component position shifting due to shrinkage. In addition, when the viscosity of the adhesive is high, the operability of the adhesive (ease of coating, etc.) is reduced.

[0013] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a curable composition having both excellent photocurability and excellent thermal curability (thermosetting) and having a low viscosity and a small curing shrinkage.

[0014] Solutions to Solve Problems

[0015] The present invention which can achieve the above-mentioned object is as follows;

[0016] [1] A curable composition comprising the following components (1) to (4),

[0017] (1) Compounds having a (meth)acryloyl group,

[0018] (2) a polythiol compound having two or more mercapto groups in one molecule,

[0019] (3) Photoradical generators, and

[0020] (4) Latent curing agent,

[0021] The component (1) comprises the following component (1-1):

[0022] (1-1) a compound having a poly(oxyalkylene) chain and a (meth)acryloyl group and having a (meth)acryloyl group equivalent of 300 or more;

[0023] [2] The curable composition according to [1] above, wherein the poly(oxyalkylene) chain comprises at least one selected from the group consisting of an oxyethylene unit, an oxypropylene unit, and an oxybutylene unit;

[0024] [3] The curable composition according to [1] or [2] above, wherein the amount of the component (1-1) is 15 to 100 parts by weight per 100 parts by weight of the component (1);

[0025] [4] The curable composition according to any one of [1] to [3] above, wherein the component (2) comprises a polythiol compound having 2 to 6 mercapto groups in one molecule;

[0026] [5] The curable composition according to any one of [1] to [4] above, wherein the molar ratio of the total of the acryloyl groups and methacryloyl groups in the component (1) to the mercapto groups in the component (2) (the total of the acryloyl groups and methacryloyl groups in the component (1) / the mercapto groups in the component (2)) is 0.5 to 2.0;

[0027] [6] The curable composition according to any one of [1] to [5] above, wherein the component (4) comprises an amine-epoxy adduct compound and / or an amine-isocyanate adduct compound;

[0028] [7] An adhesive comprising the curable composition according to any one of [1] to [6] above;

[0029] [8] The adhesive according to [7], which is used for bonding components of a camera module;

[0030] [9] A sealant comprising the curable composition according to any one of [1] to [6] above;

[0031]

[10] A coating agent comprising the curable composition according to any one of [1] to [6] above;

[0032]

[11] A method for manufacturing a camera module, comprising the following steps (I) to (III):

[0033] (I) a step of positioning a first adhesive member coated with the curable composition described in any one of [1] to [6] above and a second adhesive member;

[0034] (II) a step of curing the curable composition by light irradiation to temporarily fix the first adhesive member and the second adhesive member; and

[0035] (III) A step of curing the curable composition by heating to formally fix the first adhesive member and the second adhesive member.

[0036] Effects of the Invention

[0037] According to the present invention, it is possible to obtain a curable composition which has both excellent photocurability and excellent heat curability, and has a low viscosity and a small curing shrinkage. DETAILED DESCRIPTION

[0038] <Curable composition>

[0039] The curable composition of the present invention comprises the following components (1) to (4):

[0040] (1) Compounds having a (meth)acryloyl group,

[0041] (2) a polythiol compound having two or more mercapto groups in one molecule (hereinafter sometimes referred to as a "polythiol compound"),

[0042] (3) Photoradical generators, and

[0043] (4) Latent curing agent.

[0044] One of the characteristics of the present invention is that the component (1) comprises the following component (1-1):

[0045] (1-1) A compound having a poly(oxyalkylene) chain and a (meth)acryloyl group, and having a (meth)acryloyl equivalent of 300 or more. By using the component (1-1), a curable composition having both excellent photocurability and excellent thermocurability and having a small cure shrinkage can be obtained.

[0046] The curable composition of the present invention has a characteristic of low viscosity. From the viewpoint of operability, the viscosity of the curable composition of the present invention is preferably less than 10 Pa·s, and more preferably less than 8 Pa·s. The lower limit of the viscosity of the curable composition of the present invention is not particularly limited, and the viscosity is preferably greater than 0.05 Pa·s, and more preferably greater than 0.1 Pa·s. It should be noted that the viscosity of the curable composition is a value measured using an E-type viscometer under the conditions of temperature: 25°C, rotation speed: 20 rpm and rotor: 3°×R9.7.

[0047] Components (1) to (4) and component (1-1) may be used alone or in combination of two or more. When the curable composition of the present invention contains components other than components (1) to (4) and component (1-1), the components may be used alone or in combination of two or more. Each component will be described below in order.

[0048] <(1) Compounds having a (meth)acryloyl group>

[0049] In the present invention, the compound having a (meth)acryloyl group used as component (1) mainly plays a role in improving the adhesive strength. In the present invention, "(meth)acryloyl group" means one or both of an acryloyl group and a methacryloyl group.

[0050] Component (1) includes a compound having a poly(oxyalkylene) chain and a (meth)acryloyl equivalent of 300 or more (hereinafter sometimes referred to as component (1-1) of a "POA-(meth)acryloyl compound"). In the present invention, "poly(oxyalkylene) chain" refers to a compound of the formula: -(OR) n-(wherein, R represents an alkylene group and n represents a number greater than 2.) The alkylene group in the poly(oxyalkylene) chain may be linear or branched. In addition, the number of oxyalkylene units represented by the formula: -(OR)-, i.e., n, may be a decimal. It should be noted that compounds having only oxyalkylene units in which n is 1 but not having a poly(oxyalkylene) chain (e.g., ethylene glycol di(meth)acrylate) are not included in the POA-(meth)acryloyl compound.

[0051] The (meth)acryloyl equivalent of a POA-(meth)acryloyl compound refers to a value obtained by dividing the weight average molecular weight of the compound by the number of (meth)acryloyl groups in one molecule of the compound ((meth)acryloyl equivalent=weight average molecular weight / number of (meth)acryloyl groups in one molecule).

[0052] Regarding POA-(meth)acryloyl compounds, since they are compounds having a poly(oxyalkylene) chain composed of oxyalkylene units, the weight average molecular weight is used as the molecular weight for calculating the (meth)acryloyl equivalent thereof. The weight average molecular weight can be measured by gel permeation chromatography (GPC). Specifically, the weight average molecular weight can be calculated as follows: using LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, using ShodexK-800P / K-804L / K-804L manufactured by Showa Denko K.K. as a column, using chloroform or the like as a mobile phase, measuring at a column temperature of 40°C, and calculating using a standard curve of standard polystyrene.

[0053] From the viewpoint of curability, viscosity and cure shrinkage of the curable composition, the weight average molecular weight of the POA-(meth)acryloyl compound is preferably 500 or more, more preferably 600 or more, further preferably 700 or more, and preferably 4000 or less, more preferably 3000 or less, further preferably 2000 or less.

[0054] When the POA-(meth)acryloyl compound is a mixture, the number of (meth)acryloyl groups in one molecule of the compound represents an average value per one molecule. In addition, when both acryloyl groups and methacryloyl groups are present in one molecule of the compound, the number refers to the total number of acryloyl groups and methacryloyl groups in one molecule.

[0055] The number of (meth)acryloyl groups in one molecule of the POA-(meth)acryloyl compound can be calculated from, for example, the weight average molecular weight and the iodine value measured by the method specified in JIS K0070.

[0056] The number of (meth)acryloyl groups in one molecule of the POA-(meth)acryloyl compound is preferably 1-6, more preferably 2-5, further preferably 2-4, from the viewpoint of the curability, viscosity and cure shrinkage of the curable composition.

[0057] The (meth)acryloyl equivalent of the POA-(meth)acryloyl compound needs to be 300 or more. From the viewpoint of the curability, viscosity and cure shrinkage of the curable composition, the (meth)acryloyl equivalent is preferably 320 or more, more preferably 350 or more. On the other hand, from the viewpoint of curability and viscosity, the (meth)acryloyl equivalent is preferably 1000 or less, more preferably 800 or less.

[0058] The poly(oxyalkylene) chain of the POA-(meth)acryloyl compound preferably comprises at least one selected from oxyethylene units, oxypropylene units and oxybutylene units, and more preferably is composed of at least one selected from oxyethylene units, oxypropylene units and oxybutylene units. Here, the oxypropylene unit can be a straight chain (i.e., -O-(CH2)3-) or a branched chain (e.g., -O-CH2-CH(CH3)-). In addition, the oxybutylene unit can be a straight chain (i.e., -O-(CH2)4-) or a branched chain (e.g., -O-CH2-CH(CH2CH3)-).

[0059] Examples of the POA-(meth)acryloyl compound include the following compounds. In addition, the following compounds may be used alone or in combination of two or more.

[0060] (POA-(meth)acryloyl compound having one acryloyl group or methacryloyl group in one molecule)

[0061] Methoxypolyethylene glycol (meth)acrylate

[0062] Methoxypolypropylene glycol (meth)acrylate

[0063] Methoxy polytetramethylene glycol (meth)acrylate

[0064] Phenoxy polyethylene glycol (meth)acrylate

[0065] Nonylphenoxy polyethylene glycol (meth)acrylate

[0066] In addition, in this invention, "(meth)acrylate" means one or both of acrylate and methacrylate.

[0067] (POA-(meth)acryloyl compound having two (meth)acryloyl groups in one molecule)

[0068] Polyethylene glycol di(meth)acrylate

[0069] Polypropylene glycol di(meth)acrylate

[0070] Polytetramethylene glycol di(meth)acrylate

[0071] EO modified bisphenol A di(meth)acrylate

[0072] PO modified bisphenol A di(meth)acrylate

[0073] EO modified bisphenol F di(meth)acrylate

[0074] PO modified bisphenol F di(meth)acrylate

[0075] In the present invention, "EO modification" means modification by addition of ethylene oxide (EO), and "PO modification" means modification by addition of propylene oxide (PO).

[0076] (Compound having 3 or more (meth)acryloyl groups in one molecule)

[0077] Ethoxylated pentaerythritol tetra(meth)acrylate

[0078] Here, ethoxylated pentaerythritol tetra(meth)acrylate refers to a compound having a structure in which "pentaerythritol having a poly(oxyethylene) chain" and "four (meth)acrylates" are bonded via ester bonds.

[0079] Component (1-1) preferably comprises at least one selected from polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate and ethoxylated pentaerythritol tetra(meth)acrylate, more preferably at least one selected from polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate and ethoxylated pentaerythritol tetra(meth)acrylate.

[0080] From the viewpoint of curability, viscosity and cure shrinkage of the curable composition, the amount of component (1-1) is preferably 15 to 100 parts by weight, more preferably 19.5 to 100 parts by weight, and further preferably 19.5 to 99.5 parts by weight per 100 parts by weight of component (1).

[0081] Next, compounds having (meth)acryloyl groups other than POA-(meth)acryloyl compounds (hereinafter sometimes referred to as "(meth)acryloyl compounds") are described. The number of (meth)acryloyl groups in one molecule of the (meth)acryloyl compound only needs to be 1 or more. When the (meth)acryloyl compound is a mixture, the number represents the average value per one molecule. In addition, when both acryloyl groups and methacryloyl groups are present in one molecule, the number refers to the total number of acryloyl groups and methacryloyl groups in one molecule. The number of (meth)acryloyl groups in one molecule of the (meth)acryloyl compound (excluding the phosphoric acid-modified (meth)acrylate described later) is preferably 1 to 6, more preferably 2 to 6, and even more preferably 2 to 4.

[0082] The molecular weight of the (meth)acryloyl compound (excluding the phosphoric acid-modified (meth)acrylate described later) is preferably 50 to 5000, more preferably 70 to 4000, and further preferably 100 to 2000. When the molecular weight is less than 50, the volatility is high, which is not good in terms of odor and handling. When the molecular weight exceeds 5000, the viscosity of the composition becomes high, resulting in a tendency for the coating property of the composition to decrease. It should be noted that a molecular weight of more than 1000 refers to a weight average molecular weight, which can be measured by gel permeation chromatography (GPC). A molecular weight of less than 1000 can be measured using a gravimetric analyzer (e.g., ESI-MS).

[0083] Examples of the (meth)acryloyl compound include the following compounds. In addition, the following compounds may be used alone or in combination of two or more.

[0084] ((Meth)acryloyl compound having one acryloyl group or methacryloyl group in one molecule)

[0085] β-Carboxyethyl (meth)acrylate

[0086] Isobornyl (meth)acrylate

[0087] Octyl / Decyl (Meth)acrylate

[0088] Ethoxylated phenyl (meth)acrylate

[0089] N-(Meth)acryloyloxyethyl hexahydrophthalimide

[0090] ω-Carboxy-polycaprolactone mono(meth)acrylate

[0091] Phthalic acid monohydroxyethyl (meth)acrylate

[0092] 2-Hydroxy-3-phenoxypropyl (meth)acrylate.

[0093] ((Meth)acryloyl compound having two (meth)acryloyl groups in one molecule)

[0094] 1,6-Hexanediol di(meth)acrylate

[0095] Ethylene glycol di(meth)acrylate

[0096] Propylene glycol di(meth)acrylate

[0097] Tetramethylene glycol di(meth)acrylate

[0098] Tricyclodecane dimethanol di(meth)acrylate

[0099] Neopentyl glycol hydroxypivalate di(meth)acrylate

[0100] Polyurethane having two (meth)acryloyl groups in one molecule

[0101] Polyester having two (meth)acryloyl groups in one molecule

[0102] Bisphenol A epoxy (meth)acrylate

[0103] Caprolactone modified epoxy (meth) acrylate

[0104] Here, the caprolactone-modified epoxy (meth)acrylate having two (meth)acryloyl groups in one molecule (sometimes referred to simply as "caprolactone-modified epoxy (meth)acrylate" in this specification) refers to a compound that can be produced by reacting (meth)acrylic acid with ε-caprolactone to produce a carboxylic acid compound, and then reacting the carboxylic acid compound with a difunctional epoxy compound.

[0105] ((Meth)acryloyl compound having three or more (meth)acryloyl groups in one molecule)

[0106] Trimethylolpropane tri(meth)acrylate

[0107] Pentaerythritol (tri / tetra) (meth)acrylate

[0108] Glycerol propoxy tri(meth)acrylate

[0109] Di(trimethylolpropane)tetra(meth)acrylate

[0110] Dipentaerythritol (penta / hexa) (meth)acrylate

[0111] Dipentaerythritol hexa(meth)acrylate

[0112] Polyurethane having 3 or more (meth)acryloyl groups in one molecule

[0113] A polyester having three or more (meth)acryloyl groups in one molecule.

[0114] Pentaerythritol (tri / tetra) (meth)acrylate is a mixture of pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate, and the mixing ratio (pentaerythritol tri(meth)acrylate / pentaerythritol tetra(meth)acrylate) is preferably 5 / 95 to 95 / 5, more preferably 30 / 70 to 70 / 30 by weight.

[0115] Dipentaerythritol (penta / hexa) (meth) acrylate is a mixture of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate. The mixing ratio (dipentaerythritol penta (meth) acrylate / dipentaerythritol hexa (meth) acrylate) is preferably 5 / 95 to 95 / 5, more preferably 30 / 70 to 70 / 30 by weight.

[0116] Among the above (meth)acryloyl compounds, tricyclodecane dimethanol di(meth)acrylate, bisphenol A epoxy (meth)acrylate, caprolactone-modified epoxy (meth)acrylate and dipentaerythritol hexa(meth)acrylate are preferred, and bisphenol A epoxy (meth)acrylate is more preferred.

[0117] From the viewpoint of storage stability, component (1) preferably contains phosphoric acid-modified (meth)acrylate. Here, "phosphoric acid-modified" means modified by an ester bond with phosphoric acid. Only one phosphoric acid-modified (meth)acrylate may be used, or two or more phosphoric acid-modified (meth)acrylates may be used in combination. The phosphoric acid-modified (meth)acrylate is preferably phosphoric acid-modified methacrylate.

[0118] The phosphoric acid-modified (meth)acrylate can be produced by, for example, the following method (i), but the present invention is not limited to these methods;

[0119] (i) A method of reacting a compound having a (meth)acryloyl group and a hydroxyl group with phosphoric acid.

[0120] The compound having a (meth)acryloyl group and a hydroxyl group in one molecule that can be used in the above-mentioned method (i) can be produced, for example, by the following method (ii) or (iii), but the present invention is not limited to these methods;

[0121] (ii) a method of reacting (meth)acrylic acid or (meth)acrylic acid ester with a polyol (e.g., alkylene glycol, glycerol, etc.) in such a ratio that the hydroxyl group of the polyol remains;

[0122] (iii) A method of adding an alkylene oxide (eg, ethylene oxide, propylene oxide, etc.) to (meth)acrylic acid.

[0123] As the phosphoric acid-modified (meth)acrylate, commercial products can be used. Examples of such commercial products include "EBECRYL 168" manufactured by ALLNEX Co., Ltd., "KAYAMER PM-2" and "KAYAMER PM-21" manufactured by Nippon Kayaku Co., Ltd., "LIGHT ESTER P-1M", "LIGHT ESTER P-2M", and "LIGHT ACRYLATE P-1A (N)" manufactured by Kyoeisha Chemical Co., Ltd., and "JPA-514" manufactured by Johoku Chemical Industry Co., Ltd.

[0124] The number of (meth)acryloyl groups in one molecule of the phosphoric acid-modified (meth)acrylate is preferably from 0.5 to 3, more preferably from 1 to 2, further preferably from 1 to 1.5. When the phosphoric acid-modified (meth)acrylate is a mixture, the number represents an average value per molecule.

[0125] The molecular weight of the phosphoric acid-modified (meth)acrylate is preferably from 100 to 1,000, more preferably from 150 to 800, further preferably from 200 to 600.

[0126] When a phosphoric acid-modified (meth)acrylate is used, the amount thereof is preferably from 0.001 to 5 parts by weight, more preferably from 0.01 to 3 parts by weight, further preferably from 0.05 to 2 parts by weight, per 100 parts by weight of the component (1), from the viewpoint of storage stability.

[0127] From the viewpoint of the curability of the curable composition, component (1) is preferably a compound having two or more (meth)acryloyl groups in one molecule. As a compound having two or more (meth)acryloyl groups in one molecule, it can be the above-mentioned POA-(meth)acryloyl compound, or it can be a compound other than it (i.e., the above-mentioned (meth)acryloyl compound). When a compound having two or more (meth)acryloyl groups in one molecule is used, from the viewpoint of the curability of the curable composition, its amount is preferably 10 to 100 parts by weight, more preferably 20 to 100 parts by weight, and further preferably 30 to 99.5 parts by weight per 100 parts by weight of component (1).

[0128] In one embodiment of the present invention, component (1) preferably comprises component (1-1) and a phosphoric acid-modified (meth)acrylate, and more preferably is a mixture of component (1-1) and a phosphoric acid-modified (meth)acrylate. In this embodiment, component (1-1) preferably comprises at least one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate, and more preferably is at least one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate.

[0129] In another embodiment of the present invention, component (1) preferably comprises at least one selected from tricyclodecane dimethanol di(meth)acrylate, bisphenol A type epoxy (meth)acrylate, caprolactone-modified epoxy (meth)acrylate and dipentaerythritol hexa(meth)acrylate, component (1-1), and phosphoric acid-modified (meth)acrylate, and more preferably is a mixture of at least one selected from tricyclodecane dimethanol di(meth)acrylate, bisphenol A type epoxy (meth)acrylate, caprolactone-modified epoxy (meth)acrylate and dipentaerythritol hexa(meth)acrylate, component (1-1), and phosphoric acid-modified (meth)acrylate. In this embodiment, component (1-1) preferably comprises at least one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate and ethoxylated pentaerythritol tetra(meth)acrylate, and more preferably at least one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate and ethoxylated pentaerythritol tetra(meth)acrylate.

[0130] In another embodiment of the present invention, component (1) preferably comprises component (1-1), bisphenol A epoxy (meth)acrylate, and phosphoric acid-modified (meth)acrylate, and more preferably is a mixture of component (1-1), bisphenol A epoxy (meth)acrylate, and phosphoric acid-modified (meth)acrylate. In this embodiment, component (1-1) preferably comprises at least one selected from polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate, and more preferably is at least one selected from polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate.

[0131] From the viewpoint of the curability, viscosity and cure shrinkage of the curable composition, the amount of component (1) is preferably at least 10 wt %, more preferably at least 15 wt %, further preferably at least 20 wt %, and is preferably at most 80 wt %, more preferably at most 75 wt %, further preferably at most 70 wt %, relative to the total amount of the curable composition.

[0132] <(2) Polythiol compounds>

[0133] In the present invention, the "polythiol compound having two or more mercapto groups in one molecule" used as component (2) mainly functions as a curing agent that reacts with component (1) by irradiation with light such as ultraviolet light to cure the composition. The number of mercapto groups in one molecule of the polythiol compound is preferably 2 to 6, more preferably 3 to 6, further preferably 3 to 5, and particularly preferably 3 or 4.

[0134] As the polythiol compound, a commercially available product may be used, or a compound produced by a known method (for example, the method described in JP-A-2012-153794 or WO-2001 / 00698) may be used.

[0135] Examples of polythiol compounds include partial esters of polyols and mercapto organic acids, and full esters of polyols and mercapto organic acids. Here, partial esters refer to esters of polyols and carboxylic acids, and are esters in which a part of the hydroxyl groups of the polyols form ester bonds; full esters refer to esters in which all the hydroxyl groups of the polyols form ester bonds.

[0136] Examples of the polyol include ethylene glycol, trimethylolethane, trimethylolpropane, pentaerythritol, and dipentaerythritol.

[0137] Examples of the mercapto organic acid include mercaptoaliphatic monocarboxylic acids such as mercaptoacetic acid, mercaptopropionic acid (e.g., 3-mercaptopropionic acid), and mercaptobutyric acid (e.g., 3-mercaptobutyric acid, 4-mercaptobutyric acid); esters containing a mercapto group and a carboxyl group obtained by an esterification reaction between a hydroxy acid and a mercapto organic acid; mercaptoaliphatic dicarboxylic acids such as mercaptosuccinic acid and dimercaptosuccinic acid (e.g., 2,3-dimercaptosuccinic acid); mercaptoaromatic monocarboxylic acids such as mercaptobenzoic acid (e.g., 4-mercaptobenzoic acid); and the like. The number of carbon atoms of the mercaptoaliphatic monocarboxylic acid is preferably 2 to 8, more preferably 2 to 6, further preferably 2 to 4, and particularly preferably 3. Among the mercapto organic acids, mercaptoaliphatic monocarboxylic acids having 2 to 8 carbon atoms are preferred, mercaptoacetic acid, 3-mercaptopropionic acid, 3-mercaptobutyric acid, and 4-mercaptobutyric acid are more preferred, and 3-mercaptopropionic acid is further preferred.

[0138] Specific examples of partial esters of polyols and mercapto organic acids include trimethylolethane bis(thioglycolate), trimethylolethane bis(3-mercaptopropionate), trimethylolethane bis(3-mercaptobutyrate), trimethylolethane bis(4-mercaptobutyrate), trimethylolpropane bis(thioglycolate), trimethylolpropane bis(3-mercaptopropionate), trimethylolpropane bis(3-mercaptobutyrate). , trimethylolpropane bis(4-mercaptobutyrate), pentaerythritol tris(thioglycolate), pentaerythritol tris(3-mercaptopropionate), pentaerythritol tris(3-mercaptobutyrate), pentaerythritol tris(4-mercaptobutyrate), dipentaerythritol tetra(thioglycolate), dipentaerythritol tetra(3-mercaptopropionate), dipentaerythritol tetra(3-mercaptobutyrate), dipentaerythritol tetra(4-mercaptobutyrate), etc.

[0139] Specific examples of the full esters of polyols and mercapto organic acids include ethylene glycol bis(thioglycolate), ethylene glycol bis(3-mercaptopropionate), ethylene glycol bis(3-mercaptobutyrate), ethylene glycol bis(4-mercaptobutyrate), trimethylolethane tris(thioglycolate), trimethylolethane tris(3-mercaptopropionate), trimethylolethane tris(3-mercaptobutyrate), trimethylolethane tris(4-mercaptobutyrate), trimethylolpropane tris(thioglycolate), and trimethylolpropane tris(thioglycolate). tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), trimethylolpropane tris(4-mercaptobutyrate), pentaerythritol tetrakis(mercaptoacetic acid), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(4-mercaptobutyrate), dipentaerythritol hexa(mercaptoacetic acid), dipentaerythritol hexa(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptobutyrate), dipentaerythritol hexa(4-mercaptobutyrate), and the like.

[0140] From the viewpoint of storage stability, the partial ester and full ester preferably contain a very small amount of basic impurities, and more preferably do not require the use of a basic substance in production.

[0141] In addition, as component (2), polythiol compounds produced using a basic substance as a reaction catalyst in the production process such as alkane polythiol compounds such as 1,4-butanedithiol, 1,6-hexanedithiol, and 1,10-decanedithiol; polyethers containing terminal mercapto groups; polythioethers containing terminal mercapto groups; polythiol compounds obtained by the reaction of an epoxy compound with hydrogen sulfide; and polythiol compounds having terminal mercapto groups obtained by the reaction of a polythiol compound with an epoxy compound can also be used. The polythiol compound produced using a basic substance is preferably used after dealkalization treatment to reduce the basic metal (alkali metal) ion concentration to 50 ppm by weight or less.

[0142] As the dealkalization treatment of the polythiol compound produced using an alkaline substance, for example, there can be cited a method of dissolving the polythiol compound in an organic solvent such as acetone and methanol, adding an acid such as dilute hydrochloric acid and dilute sulfuric acid to neutralize it, and then desalting it by extraction / washing; a method of adsorption using an ion exchange resin; a method of purification by distillation, etc., but it is not limited to these methods.

[0143] In addition, as component (2), for example, tris[(3-mercaptopropionyloxy)ethyl]isocyanurate, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, tris(3-mercaptopropyl)isocyanurate, bis(3-mercaptopropyl)isocyanurate, 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, and 4,4'-isopropylidene diphenylbis(3-mercaptopropyl)ether can be used.

[0144] The component (2) preferably contains a polythiol compound having 2 to 6, more preferably 3 to 6, further preferably 3 to 5, particularly preferably 3 or 4 mercapto groups in one molecule.

[0145] In one embodiment of the present invention, component (2) preferably comprises at least one selected from pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate) and tris(3-mercaptopropyl)isocyanurate, and more preferably comprises at least one selected from pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate) and tris(3-mercaptopropyl)isocyanurate.

[0146] In another embodiment of the present invention, component (2) preferably comprises pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate) or tris(3-mercaptopropyl)isocyanurate, more preferably pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate) or tris(3-mercaptopropyl)isocyanurate, and even more preferably pentaerythritol tetrakis(3-mercaptopropionate).

[0147] From the viewpoint of curability, the molar ratio of the total amount of acryloyl groups and methacryloyl groups in the component (1) to the mercapto groups in the component (2) (the total amount of acryloyl groups and methacryloyl groups in the component (1) / the mercapto groups in the component (2)) is preferably from 0.5 to 2.0, more preferably from 0.6 to 1.6, further preferably from 0.7 to 1.5, particularly preferably from 0.8 to 1.3.

[0148] From the viewpoint of the curability, viscosity and cure shrinkage of the curable composition, the amount of component (2) is preferably at least 10 wt %, more preferably at least 15 wt %, further preferably at least 20 wt %, and is preferably at most 50 wt %, more preferably at most 45 wt %, further preferably at most 40 wt %, relative to the total amount of the curable composition.

[0149] <(3) Photoradical generator>

[0150] In the present invention, the photoradical generator used as component (3) is not particularly limited. Examples of the photoradical generator include alkylphenone photoradical generators, acylphosphine oxide photoradical generators, oxime ester photoradical generators, α-hydroxyketone photoradical generators, etc. The photoradical generator is preferably an alkylphenone photoradical generator.

[0151] Examples of the phenyl alkyl ketone-based photoradical generator include 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-[4-(4-morpholino)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, benzophenone, methyl benzophenone, o-benzoylbenzoic acid, benzoylethyl ether, 2,2-diethoxybenzoic acid, Acetophenone, 2,4-diethylthioxanthone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, 4,4'-bis(diethylamino)benzophenone, 1-hydroxycyclohexylphenylketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, oligomers of 2-hydroxy-1-(4-isopropenylphenyl)-2-methylpropane-1-one, and the like.

[0152] Examples of the acylphosphine oxide-based photoradical generator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0153] Examples of the oxime ester photoradical generator include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxime) and 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone O-acetyloxime.

[0154] Examples of the α-hydroxyketone-based photoradical generator include benzoin, benzoin methyl ether, benzoin butyl ether, 1-hydroxycyclohexyl phenyl ketone, 1-phenyl-2-hydroxy-2-methylpropane-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexyl phenyl ketone.

[0155] Examples of commercially available photoradical generators include “Irgacure 1173” (2-hydroxy-2-methyl-1-phenylpropane-1-one) manufactured by BASF, “Irgacure OXE01” (1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime)), and “Irgacure OXE02” (1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone O-acetoxime) manufactured by IGM Resins BV, “Esacure KTO 46” (a mixture of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane], and a methylbenzophenone derivative), and “Esacure KIP 47” (a mixture of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane], and a methylbenzophenone derivative manufactured by IGM Resins BV. 150" (oligomer of 2-hydroxy-1-(4-isopropenylphenyl)-2-methylpropane-1-one), etc.

[0156] From the viewpoint of obtaining a curable composition that can be effectively photocured when irradiated with light, the amount of component (3) is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, and further preferably 0.1% by weight or more relative to the entire curable composition. On the other hand, from the viewpoint of suppressing outgassing caused by the photoradical generator or its decomposition product remaining in the cured product, the amount of component (3) is preferably 10% by weight or less, more preferably 5% by weight or less, and further preferably 2% by weight or less relative to the entire curable composition.

[0157] <(4) Latent curing agent>

[0158] In the present invention, the latent curing agent used as component (4) is an additive known in the field of epoxy resins, etc., which does not cure epoxy resins, etc. at room temperature (25° C.), but can cure epoxy resins, etc. by heating. In the present invention, the latent curing agent plays a role in promoting the reaction of component (1) (compound having a (meth)acryloyl group) and component (2) (polythiol compound having two or more mercapto groups in one molecule).

[0159] Examples of the latent curing agent include imidazole compounds that are solid at room temperature, amine-epoxy adduct compounds (reaction products of amine compounds and epoxy compounds), and amine-isocyanate adduct compounds (reaction products of amine compounds and isocyanate compounds).

[0160] Examples of the imidazole compound that is solid at room temperature include 2-heptadecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine, 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine / isocyanuric acid adduct, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, and N-(2-methylimidazolyl-1-ethyl)urea.

[0161] Examples of epoxy compounds used as raw materials for amine-epoxy adduct compounds include: polyglycidyl ethers obtained by reacting polyphenols such as bisphenol A, bisphenol F, catechol, and resorcinol, or polyols such as glycerol or polyethylene glycol with epichlorohydrin; glycidyl ether esters obtained by reacting hydroxy acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid with epichlorohydrin; polyglycidyl esters obtained by reacting polycarboxylic acids such as phthalic acid and terephthalic acid with epichlorohydrin; glycidyl amine compounds obtained by reacting 4,4'-diaminodiphenylmethane or m-aminophenol with epichlorohydrin; and polyfunctional epoxy compounds such as epoxidized phenol novolac resins, epoxidized cresol novolac resins, and epoxidized polyolefins; or monofunctional epoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate; and the like.

[0162] The amine compound used as a raw material of the amine-epoxy addition compound or the amine-isocyanate addition compound may be any compound having one or more active hydrogen atoms capable of undergoing addition reaction with an epoxy group or an isocyanate group (also known as an isocyanato group) in one molecule and one or more amino groups (at least one of a primary amino group, a secondary amino group, and a tertiary amino group) in one molecule. Examples of such amine compounds include aliphatic amine compounds such as diethylenetriamine, triethylenetetramine, propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diaminodicyclohexylmethane; aromatic amine compounds such as 4,4'-diaminodiphenylmethane and 2-methylaniline; heterocyclic compounds containing nitrogen atoms such as 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, and piperazine; and the like.

[0163] In addition, if a compound having a tertiary amino group is used, an excellent latent curing agent can be produced. Examples of the compound having a tertiary amino group include amines having a tertiary amino group such as dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, N-methylpiperazine, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole; 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1-butoxymethyl-2-dimethylaminoethanol, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2- alcohols, phenols, thiols, carboxylic acids and hydrazides having a tertiary amino group, such as 1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, N-β-hydroxyethylmorpholine, 2-dimethylaminoethanethiol, 2-mercaptopyridine, 2-benzimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 4-mercaptopyridine, N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, picolinic acid, N,N-dimethylglycine hydrazide, N,N-dimethylpropanoic acid hydrazide, nicotinic acid hydrazide, isonicotinic acid hydrazide (isoniazid), etc.

[0164] When an amine-epoxy adduct is produced by addition reaction of an epoxy compound with an amine compound, an active hydrogen compound having two or more active hydrogen atoms in one molecule may be further added. Examples of such active hydrogen compounds include polyphenols such as bisphenol A, bisphenol F, bisphenol S, hydroquinone, catechol, resorcinol, pyrogallol, and phenol novolac resins, polyols such as trimethylolpropane, polycarboxylic acids such as adipic acid and phthalic acid, 1,2-dimercaptoethane, 2-mercaptoethanol, 1-mercapto-3-phenoxy-2-propanol, thioglycolic acid, anthranilic acid, and lactic acid.

[0165] Examples of the isocyanate compound used as a raw material for the amine-isocyanate addition compound include monofunctional isocyanate compounds such as butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, and benzyl isocyanate; polyfunctional isocyanate compounds such as hexamethylene diisocyanate, toluene diisocyanate (e.g., 2,4-toluene diisocyanate, 2,6-toluene diisocyanate), 1,5-naphthalene diisocyanate, diphenylmethane-4,4′-diisocyanate, isophorone diisocyanate, xylylene diisocyanate, p-phenylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate; and terminal isocyanate group-containing compounds obtained by reacting these polyfunctional isocyanate compounds with an active hydrogen compound; and the like. Examples of such a terminal isocyanate group-containing compound include an addition compound having a terminal isocyanate group obtained by a reaction between tolylene diisocyanate and trimethylolpropane, and an addition compound having a terminal isocyanate group obtained by a reaction between tolylene diisocyanate and pentaerythritol.

[0166] The latent curing agent can be easily obtained, for example, by appropriately mixing the above-mentioned raw materials, reacting them at a temperature of 20°C to 200°C, cooling and solidifying them, and then crushing them; or reacting the above-mentioned raw materials in a solvent such as methyl ethyl ketone, dioxane, tetrahydrofuran, etc., removing the solvent, and then crushing the solid component.

[0167] Commercially available products can be used as latent curing agents. Examples of commercially available products of amine-epoxy adduct compounds include "Ajicure PN-23", "Ajicure PN-40", "Ajicure PN-50", and "Ajicure PN-H" manufactured by Ajinomoto Fine-Techno Co., Inc., "Hardener X-3661S" and "Hardener X-3670S" manufactured by ACR, and "NOVACURE HX-3742" and "NOVACURE HX-3721" manufactured by Asahi Kasei Corporation. Examples of commercially available products of the amine-isocyanate adduct-based compound include "Fujicure FXR-1000", "Fujicure FXR-1030", "Fujicure FXR-1020", "Fujicure FXR-1030", "Fujicure FXR-1081" and "Fujicure FXR-1121" manufactured by T&K TOKA CORPORATION.

[0168] Component (4) preferably comprises an amine-epoxy addition compound and / or an amine-isocyanate addition compound, more preferably an amine-epoxy addition compound and / or an amine-isocyanate addition compound, further preferably an amine-epoxy addition compound or an amine-isocyanate addition compound, and particularly preferably an amine-epoxy addition compound.

[0169] From the viewpoint of curability, the amount of component (4) is preferably more than 1% by weight, more preferably more than 3% by weight, and further more preferably more than 5% by weight relative to the entire curable composition. In addition, from the viewpoint of storage stability, the amount of component (4) is preferably less than 20% by weight, more preferably less than 15% by weight, and further more preferably less than 10% by weight relative to the entire curable composition.

[0170] <(5) Epoxy resin>

[0171] The curable composition of the present invention may contain an epoxy resin as a component (5). Examples of the epoxy resin include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, aromatic glycidylamine type epoxy resin (e.g., tetraglycidyl diaminodiphenylmethane, triglycidyl p-aminophenol, diglycidyl toluidine, diglycidyl Aniline, etc.), alicyclic epoxy resins, aliphatic chain epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, epoxy resins with a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalene diols, diglycidyl ethers of phenols, and diglycidyl ethers of alcohols, as well as alkyl substituted products, halides and hydrogenated products (hydrides) of these epoxy resins. Only one epoxy resin may be used, or two or more epoxy resins may be used in combination. The epoxy resin may be a substance that is liquid at 25°C, or a substance that is solid at 25°C. The epoxy resin may be a monomer (i.e., a monomeric epoxy resin).

[0172] From the viewpoint of temporary fixation and the adhesion of liquid crystal polymers (LCP) and other components that are difficult to bond, the epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule and being solid at 25°C. The epoxy resin may also be contained in a liquid epoxy resin that is liquid at 25°C, but from the viewpoint of the above-mentioned effect, the epoxy resin is preferably not contained in a liquid epoxy resin, or is contained in an amount of 20 parts by weight or less per 100 parts by weight of the epoxy resin. The amount of the liquid epoxy resin is preferably less than 10 parts by weight, and further preferably less than 5 parts by weight per 100 parts by weight of the epoxy resin. The epoxy resin is particularly preferably not contained in a liquid epoxy resin.

[0173] From the viewpoint of reactivity, the epoxy equivalent of the epoxy resin is preferably 50 to 5000, more preferably 100 to 3000, and further preferably 150 to 1000. Here, the epoxy equivalent refers to the number of grams of a compound containing 1 gram equivalent of epoxy groups (unit: g / eq). In other words, the epoxy equivalent refers to the value obtained by dividing the molecular weight of a compound containing an epoxy group by the number of epoxy groups possessed by the compound, i.e., the molecular weight per one epoxy group. The epoxy equivalent can be measured according to the method specified in JIS K 7236.

[0174] In one embodiment of the present invention, component (5) preferably comprises at least one selected from bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, and biphenyl epoxy resin, and more preferably at least one selected from bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, and biphenyl epoxy resin. In this embodiment, bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, and biphenyl epoxy resin each have two or more epoxy groups in one molecule and are solid at 25°C.

[0175] In another embodiment of the present invention, component (5) preferably comprises bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, or biphenyl epoxy resin, and more preferably bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, or biphenyl epoxy resin. In this embodiment, bisphenol A epoxy resin, bisphenol F epoxy resin, dicyclopentadiene epoxy resin, and biphenyl epoxy resin all have two or more epoxy groups in one molecule and are solid at 25°C.

[0176] In another embodiment of the present invention, component (5) preferably comprises a bisphenol A type epoxy resin having two or more epoxy groups in one molecule and being solid at 25°C, more preferably a bisphenol A type epoxy resin having two or more epoxy groups in one molecule and being solid at 25°C.

[0177] When an epoxy resin is used as component (5), from the viewpoint of curability, the amount thereof is preferably at least 1 wt %, more preferably at least 3 wt %, further preferably at least 5 wt %, and is preferably at most 70 wt %, more preferably at most 60 wt %, further preferably at most 55 wt % relative to the total amount of the curable composition.

[0178] <Other ingredients>

[0179] In the range that does not impair the effect of the present invention, the curable composition of the present invention may contain other components different from the above components. As other components, for example: polymerization inhibitors (such as butylated hydroxytoluene, barbituric acid); antioxidants; inorganic fillers (such as calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, aluminum oxide (alumina), zinc oxide, silicon dioxide, potassium titanate, kaolin, talc, quartz powder, etc.); organic fillers such as copolymers obtained by copolymerizing "polymethyl methacrylate and / or polystyrene" with "monomers copolymerizable with these monomers"; thixotropic agents; defoamers; leveling agents; coupling agents; flame retardants; pigments; dyes; fluorescent agents, etc. Other components can be used only one, or two or more can be used in combination.

[0180] <Production and curing of curable composition>

[0181] The curable composition of the present invention can be prepared as a one-component curable composition by uniformly mixing the components using, for example, a kneader, a stirring mixer, a three-roll mill, etc. The temperature of the curable composition during mixing is usually 10 to 50°C, preferably 20 to 40°C.

[0182] The light irradiated when the curable composition of the present invention is photocured is preferably ultraviolet light. The peak wavelength of the irradiated light is preferably from 300 to 500 nm. The illuminance of the irradiated light is preferably from 100 to 5000 mW / cm 2 , preferably 300 to 4000 mW / cm 2 The exposure amount is preferably 500 to 3000 mJ / cm 2 , preferably 1000 to 3000 mJ / cm 2 .

[0183] Examples of light irradiation equipment include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, excimer lasers, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, fluorescent lamps, LED-based SPOT-type UV irradiators, xenon lamps, and DEEP UV lamps.

[0184] The heating temperature when heat-curing the curable composition of the present invention is not particularly limited, and is, for example, 50 to 150° C., preferably 60 to 100° C. The heating time when heat-curing the curable composition of the present invention is not particularly limited, and is, for example, 10 to 120 minutes, preferably 30 to 60 minutes.

[0185] <Application of curable composition>

[0186] The curable composition of the present invention has both excellent photocurability and excellent thermal curability, and can form a cured product with high bonding strength, so it can be used for adhesives, sealants, coating agents, etc. Therefore, the present invention also provides an adhesive, a sealant, and a coating agent containing the aforementioned curable composition. As an adhesive, it is preferably used for bonding between components of a camera module.

[0187] <Camera module manufacturing method>

[0188] The present invention provides a method for manufacturing a camera module, which comprises the following steps (I) to (III):

[0189] (I) a step of positioning a first adhesive member coated with the curable composition of the present invention and a second adhesive member;

[0190] (II) a step of curing the curable composition by light irradiation to temporarily fix the first adhesive member and the second adhesive member; and

[0191] (III) A step of curing the curable composition by heating to formally fix the first adhesive member and the second adhesive member. Here, the first adhesive member refers to a member coated with the curable composition of the present invention, and the second adhesive member refers to another member bonded to the first adhesive member. The second adhesive member may be coated with the curable composition of the present invention or may not be coated with the curable composition of the present invention.

[0192] According to the manufacturing method of the present invention, each member can be positioned with high accuracy, and the first adhesive member and the second adhesive member can be bonded to each other with high bonding strength, resulting in efficient manufacturing of a high-quality camera module.

[0193] In step (II), due to the arrangement positions of the first adhesive member and the second adhesive member, unirradiated portions may remain on the applied curable composition where light is not irradiated. However, since the curable composition of the present invention has good thermal curing properties, the unirradiated portions are also fully cured by the thermal curing in step (III) to achieve full curing, and a cured product having high bonding strength can be formed from the entire applied curable composition.

[0194] The light irradiation conditions in the step (II) and the heating conditions in the step (III) in the method for manufacturing a camera module of the present invention are as described above. Example

[0195] The present invention will be described in more detail below with reference to the following embodiments. However, the present invention is not limited to the following embodiments and may be implemented with appropriate modifications within the scope of the above / below purposes, all of which are included in the technical scope of the present invention.

[0196] 1. Raw materials

[0197] <Component (1): Compound having a (meth)acryloyl group>

[0198] (I) Component (1-1): a compound having a poly(oxyalkylene) chain and a (meth)acryloyl group, and having a (meth)acryloyl equivalent of 300 or more

[0199] (1A) APG-700: manufactured by Shin-Nakamura Chemical Industry Co., Ltd., polypropylene glycol #700 diacrylate, weight average molecular weight: 808, number of acryloyl groups in one molecule: 2, (meth)acryloyl equivalent: 404

[0200] (1B) A-PTMG-65: manufactured by Shin-Nakamura Chemical Industry Co., Ltd., polytetramethylene glycol #650 diacrylate, weight average molecular weight: 758, number of acryloyl groups in one molecule: 2, (meth)acryloyl equivalent: 379

[0201] (1C) ATM-35E: manufactured by Shin-Nakamura Chemical Industry Co., Ltd., ethoxylated pentaerythritol tetraacrylate, weight average molecular weight: 1892, number of acryloyl groups in one molecule: 4, (meth)acryloyl equivalent: 473

[0202] (1D) A-1000: manufactured by Shin-Nakamura Chemical Industry Co., Ltd., polyethylene glycol #1000 diacrylate, weight average molecular weight: 1108, number of acryloyl groups in one molecule: 2, (meth)acryloyl equivalent: 554.

[0203] (II) Component (1-1'): a compound having an oxyalkylene unit and a (meth)acryloyl group, and having a (meth)acryloyl equivalent of less than 300

[0204] (1E) "M-313": manufactured by Toagosei Co., Ltd., a mixture of EO-modified isocyanuric acid diacrylate and EO-modified isocyanuric acid triacrylate (content of diacrylate compound: 35% by weight, content of triacrylate compound: 65% by weight), weight average molecular weight: 404, number of acryloyl groups in one molecule: 2.65, (meth)acryloyl equivalent: 158.

[0205] (III) Compounds having a (meth)acryloyl group other than the component (1-1) and the component (1-1′)

[0206] (1F) EBECRYL600: manufactured by DAICEL-ALLNEX, bisphenol A epoxy acrylate, molecular weight: 500, number of acryloyl groups in one molecule: 2

[0207] (1G) IRR-214K: manufactured by DAICEL-ALLNEX, tricyclodecane dimethanol diacrylate, molecular weight: 300, number of acryloyl groups in one molecule: 2

[0208] (1H) DPHA: manufactured by DAICEL-ALLNEX, dipentaerythritol hexaacrylate, molecular weight: 524, number of acryloyl groups in one molecule: 6

[0209] (1I) EBECRYL3708: manufactured by DAICEL-ALLNEX, caprolactone-modified epoxy acrylate, molecular weight: 1500, number of acryloyl groups in one molecule: 2

[0210] (1J) EBECRYL 168: manufactured by DAICEL-ALLNEX, phosphoric acid-modified methacrylate, molecular weight: 270, number of methacryloyl groups in one molecule: 1.5.

[0211] <Ingredient (2): Polythiol compound>

[0212] (2A) PEMP: manufactured by SC Organic Chemicals, pentaerythritol tetrakis(3-mercaptopropionate), molecular weight: 489, number of mercapto groups in one molecule: 4

[0213] (2B) PE1: "Karenz MT" manufactured by Showa Denko K.K. Pentaerythritol tetrakis(3-mercaptobutyrate), molecular weight: 544, number of mercapto groups in one molecule: 4

[0214] (2C) TMPIC: tris(3-mercaptopropyl)isocyanurate, molecular weight: 351, number of mercapto groups in one molecule: 3.

[0215] <Ingredient (3): Photoradical generator>

[0216] (3A) Irgacure 1173: Made by BASF, 2-hydroxy-2-methyl-1-phenylpropane-1-one

[0217] (3B) Esacure KIP 150: manufactured by IGM Resins BV, an oligomer of 2-hydroxy-1-(4-isopropenylphenyl)-2-methylpropan-1-one.

[0218] <Ingredient (4): Latent curing agent>

[0219] (4A) PN-23: Aminomoto Fine Chemicals Co., Ltd., amine-epoxy adduct compound

[0220] (4B) FXR1081: manufactured by T&K TOKA Co., Ltd., an amine-isocyanate adduct compound.

[0221] <Ingredient (5): Epoxy resin>

[0222] (5A) jER1001: manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent (EPW): 475 g / eq, softening point: 64°C, number of epoxy groups in one molecule: 2

[0223] (5B) jER4005P: manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin, epoxy equivalent (EPW): 538 g / eq, softening point: 87°C, number of epoxy groups in one molecule: 2

[0224] (5C) HP-7200: manufactured by DIC Corporation, dicyclopentadiene type epoxy resin, epoxy equivalent (EPW): 258 g / eq, softening point: 56-66°C, number of epoxy groups in one molecule: 2-3

[0225] (5D) YX4000H: manufactured by Mitsubishi Chemical Corporation, biphenyl type epoxy resin, epoxy equivalent weight (EPW): 192 g / eq, melting point: 105° C., number of epoxy groups in one molecule: 2.

[0226] 2. Evaluation test

[0227] <Evaluation of viscosity>

[0228] The viscosity of the curable composition was measured using an E-type viscometer RE-80 manufactured by Toki Sangyo Co., Ltd. at a temperature of 25°C, a rotation speed of 20 rpm, and a rotor of 3°×R9.7, and evaluated using the following criteria;

[0229] (Evaluation Criteria)

[0230] ○: Viscosity less than 10 Pa・s

[0231] ×: The viscosity is 10 Pa·s or more.

[0232] <Evaluation of curability>

[0233] (1) Evaluation of photocurability

[0234] On a glass epoxy resin laminate (FR-4.0 manufactured by Lichang Industry) with a width of 2.5 mm × a length of 8.0 mm × a thickness of 0.8 mm, a curable composition was spread to a thickness of about 50 μm using a spacer (spacer) and a glass rod with a thickness of about 50 μm to form a coating film of the curable composition, and photocuring was performed under the following conditions. The appearance of the coating film after finger contact (appearance of the coating film caused by finger contact) was observed, and the photocurability was evaluated using the following criteria;

[0235] (Curing conditions)

[0236] The coating film was irradiated with a UV-LED irradiation device UniField NF150 manufactured by USHIO Electric Co., Ltd. at an illuminance of 10 mW / cm 2 UV rays (peak wavelength: 365nm) for 100 seconds (exposure 1000mJ / cm 2 );

[0237] (Evaluation Criteria)

[0238] ○: No uncured part on the coating film

[0239] ×: Uncured portions exist on the coating film.

[0240] (2) Evaluation of light and heat curing properties

[0241] The coating film of the curable composition formed on the glass epoxy resin laminate in the same manner as above was subjected to light and heat curing under the following conditions, and the appearance of the coating film after being touched by a finger was observed, and the light and heat curing properties were evaluated using the following criteria;

[0242] (Curing conditions)

[0243] The coating film was irradiated with a UV-LED irradiation device UniField NF150 manufactured by USHIO Electric Co., Ltd. at an illuminance of 10 mW / cm 2 UV rays (peak wavelength: 365nm) for 100 seconds (exposure 1000mJ / cm 2 ), and then, the light-irradiated coating film was heated at 100° C. for 30 minutes in a hot air circulation oven;

[0244] (Evaluation Criteria)

[0245] ○: No uncured part on the coating film

[0246] ×: Uncured portions exist on the coating film.

[0247] (3) Evaluation of thermal curing properties

[0248] For the coating film of the curable composition formed on the glass epoxy resin laminate in the same manner as above, heat curing was carried out under the following conditions, and the appearance of the coating film after being touched by a finger was observed, and the heat curing property was evaluated using the following criteria;

[0249] (Curing conditions)

[0250] The coating film was heated at 100°C for 30 minutes using a hot air circulation oven;

[0251] (Evaluation Criteria)

[0252] ○: No uncured part on the coating film

[0253] ×: Uncured portions exist on the coating film.

[0254] <Evaluation of curing shrinkage>

[0255] The specific gravity of the curable composition before curing and its cured product were measured using a dry automatic density meter (AccuPyc II1340) manufactured by Shimadzu Corporation, and the curing shrinkage was calculated using the following formula and evaluated based on the following criteria:

[0256] Curing shrinkage (%) = {(specific gravity of cured product - specific gravity of curable composition before curing) / specific gravity of cured product} × 100

[0257] (Evaluation Criteria)

[0258] ○: Curing shrinkage is less than 5%

[0259] ×: The curing shrinkage is 5% or more.

[0260] It should be noted that the cured product was prepared by applying the curable composition on the demoulding surface of a demoulding polyethylene terephthalate (PET) film (NS-80A), spreading it to a thickness of about 50 μm using a glass rod, and irradiating it with a UV-LED irradiation device UniField NF150 manufactured by USHIO Electric Co., Ltd. at an illuminance of 10 mW / cm 2 UV rays (peak wavelength: 365nm) for 100 seconds (exposure 1000mJ / cm 2 ), and then, the light-irradiated curable composition was heated at 100° C. for 30 minutes in a hot air circulation oven.

[0261] 3. Examples and Comparative Examples

[0262] The curable compositions of Examples 1 to 15 and Comparative Examples 1 to 4 were prepared by mixing the components in the amounts shown in the upper column of the following table. It should be noted that the "parts" described in the table represent "parts by weight". In addition, in the following table, the "(meth)acryloyl group / mercapto group" column describes the "molar ratio of the total amount of acryloyl groups and methacryloyl groups in component (1) to the mercapto groups in component (2)".

[0263] In Examples 1 to 11 and Comparative Examples 1, 2 and 4, components (1) and (4) were fully mixed, and then components (2) and (3) were added thereto, mixed, and then left to stand for degassing to prepare a curable composition. In Comparative Example 3, components (1) and (4) were fully mixed, and then component (3) was added thereto, mixed, and then left to stand for degassing to prepare a curable composition. In Examples 12 to 15, components (1) and (5) were mixed and dissolved at 100° C., and then fully cooled to room temperature (20 to 25° C.), component (4) was added thereto, mixed, and then components (2) and (3) were added thereto, mixed, and then left to stand for degassing to prepare a curable composition. It should be noted that the preparation operations in Examples 1 to 15 and Comparative Examples 1 to 4 were performed at room temperature, except for the mixing and dissolving of components (1) and (5) in Examples 12 to 15.

[0264] The results of the evaluation tests of the curable compositions of Examples 1 to 15 and Comparative Examples 1 to 4 are shown in the following table.

[0265] [Table 1]

[0266] .

[0267] [Table 2]

[0268] .

[0269] [Table 3]

[0270] .

[0271] [Table 4]

[0272] .

[0273] From the results of Examples 1 to 15, it can be seen that the curable composition of the present invention has low viscosity and excellent workability. In addition, it can be seen that the curable composition of the present invention has a small curing shrinkage, which can suppress the positional deviation caused by curing shrinkage. In contrast, the curing shrinkage of the curable compositions of Comparative Examples 1 to 4 is high. Furthermore, the viscosity of the curable compositions of Comparative Examples 2 to 4 is high, and the thermosetting property of the curable composition of Comparative Example 3 is insufficient.

[0274] Industrial Applicability

[0275] The curable composition of the present invention can be used for adhesives, sealants, coating agents (particularly adhesives for manufacturing camera modules), and the like.

Claims

1. A curable composition comprising the following components (1) to (4), (1) Compounds having a (meth)acryloyl group, (2) a polythiol compound having two or more mercapto groups in one molecule, (3) Photoradical generators, and (4) Latent curing agent, in, The component (1) comprises the following components (1-1): (1-1) a (meth)acryloyl equivalent of 300 or more, and at least one selected from polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and ethoxylated pentaerythritol tetra(meth)acrylate, The amount of component (1) is 20% by weight or more and 80% by weight or less based on the total weight of the curable composition. The amount of component (2) is 10% by weight or more and 50% by weight or less based on the total weight of the curable composition. The amount of the component (1-1) is 15 to 100 parts by weight per 100 parts by weight of the component (1).

2. The curable composition according to claim 1, wherein The (meth)acryloyl equivalent of the component (1-1) is 1,000 or less.

3. The curable composition according to claim 1 or 2, wherein Component (2) contains a polythiol compound having 2 to 6 mercapto groups in one molecule.

4. The curable composition according to claim 1 or 2, wherein The molar ratio of the total of acryloyl and methacryloyl groups in component (1) to the mercapto groups in component (2), that is, the total of acryloyl and methacryloyl groups in component (1) / mercapto groups in component (2) is 0.5 to 2.

0.

5. The curable composition according to claim 1 or 2, wherein The molar ratio of the total of acryloyl and methacryloyl groups in component (1) to the mercapto groups in component (2), that is, the total of acryloyl and methacryloyl groups in component (1) / mercapto groups in component (2) is 0.7 to 1.

5.

6. The curable composition according to claim 1 or 2, wherein Component (4) contains an amine-epoxy adduct compound and / or an amine-isocyanate adduct compound. 7 . An adhesive comprising the curable composition according to claim 1 . 8 . The adhesive according to claim 7 , which is used for bonding components of a camera module. 9 . A sealant comprising the curable composition according to claim 1 . 10 . A coating agent comprising the curable composition according to claim 1 .

11. A method for manufacturing a camera module, comprising the following steps (I) to (III): (I) a step of positioning a first adhesive member and a second adhesive member coated with the curable composition according to any one of claims 1 to 6; (II) a step of curing the curable composition by light irradiation to temporarily fix the first adhesive member and the second adhesive member; as well as (III) A step of curing the curable composition by heating to formally fix the first adhesive member and the second adhesive member.