Light-curing resin composition

Abstract

The purpose of the present invention is to provide a photocurable resin composition suitable for the production of electronic components, said resin composition curing rapidly by anionic polymerization even when irradiated with ultraviolet rays of the UV-A or UV-B region from an ultraviolet light-emitting diode.　This photocurable resin composition contains (a) a 2-methylene-1,3-dicarbonyl compound, (b) an ionic photobase generator, and (c) a photosensitizer. The 2-methylene-1,3-dicarbonyl compound contains at least one specific structural unit. The ionic photobase generator is a salt containing a specific anion (i) and cation (ii).

Description

[Technical field]

[0001] The present invention relates to a photocurable resin composition that is rapidly cured by anionic polymerization even when irradiated with ultraviolet light in the UV-A or UV-B region from an ultraviolet light-emitting diode. [Background technology]

[0002] In recent years, the use of curable resin compositions containing 2-methylene-1,3-dicarbonyl compounds such as methylene malonate as adhesives, etc., has been considered in the manufacture of electronic components. Such curable resin compositions cure in a short time even at low temperatures such as room temperature, and are therefore useful in avoiding adverse effects of heat for curing and improving manufacturing efficiency.

[0003] 2-methylene-1,3-dicarbonyl compounds such as methylene malonate are typically polymerized by Michael addition in the presence of a basic substance as an initiator. This polymerization is a type of anionic polymerization. A photocurable resin composition is being developed that is obtained by combining this 2-methylene-1,3-dicarbonyl compound with a photobase generator and is cured by the action of a basic substance generated from the photobase generator upon irradiation with electromagnetic waves, such as ultraviolet light. In general, resin compositions that are cured by radicals or cations generated by light are extremely useful because the region and timing of the curing can be easily controlled, and are used in various industrial fields for adhesion, coating, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Application Publication No. WO2019 / 116931 [Patent Document 2] Patent Publication No. 2015-512460 [Patent Document 3] International Application Publication No. WO2019 / 014528 [Patent Document 4] Patent Publication No. 2017-036361 [Non-patent literature]

[0005] [Non-Patent Document 1] Plastics Age, October 2018, Page 69 [Non-Patent Document 2] Wako Pure Chemical News July 2017 Vol.85 No.3 Pages 16-17 Summary of the Invention [Problem to be solved by the invention]

[0006] Ultraviolet light is usually used as the electromagnetic wave for generating a base substance from a photobase generator. Conventionally, mercury lamps were generally used as a source of ultraviolet light, but recently ultraviolet light-emitting diodes (UV-LEDs) are becoming more and more popular because they do not contain toxic mercury and have great industrial advantages such as energy saving, space saving, and long life.

[0007] Conventional photocurable resin compositions are usually premised on the use of deep ultraviolet light with a wavelength of about 254 nm emitted by a mercury lamp. For example, Patent Document 1 illustrates anionic polymerization of a resin composition containing a highly reactive anion-polymerizable compound and a photobase generator by irradiation with ultraviolet light with a wavelength of 254 nm. However, UV-LEDs currently in wide use have a peak wavelength of 280 nm or more, and in particular, gallium nitride-based ones are, in principle, limited to ultraviolet light with a peak wavelength of about 365 nm or more (see Non-Patent Document 1). For this reason, it is not possible to efficiently generate a basic substance from a conventional photobase generator as described in Patent Document 1 by irradiation with ultraviolet light from these UV-LEDs, particularly ultraviolet light in the UV-A or UV-B region.

[0008] There are known polymerization initiators that can be used for general purposes and can efficiently generate radicals by irradiation with ultraviolet rays from a UV-LED (Patent Document 2, Non-Patent Document 1). However, the curing of a curable resin composition by radical polymerization has a problem in that curing is insufficient in areas exposed to air due to oxygen inhibition.

[0009] As another method for curing a curable resin composition by irradiation with electromagnetic waves, photocationic polymerization using a photoacid generator is known. However, the acidic substances generated by irradiation with light are often strong acids, and there is a risk of metal corrosion due to the acidic substances, so photocationic polymerization is not suitable for the manufacture of electronic parts that include many metal parts.

[0010] On the other hand, photoanionic polymerization using a photobase generator does not cause problems such as oxygen inhibition or corrosion due to acidic substances. Non-Patent Document 2 discloses a photobase generator that can be used with UV-LED and a curing reaction using the same. However, this reaction is a reaction in which a mixture of an epoxy resin and a thiol or carboxylic acid is cured in the presence of a basic substance as a curing accelerator, and is not a polymerization reaction of an olefin. In addition, this reaction requires heating (80 to 120°C or 150°C) after exposure. Therefore, this reaction is not suitable for applications where adverse effects due to heat for curing are a concern.

[0011] In order to solve the above-mentioned problems of the conventional art, the present invention aims to provide a photocurable resin composition which is rapidly cured by anionic polymerization even when irradiated with ultraviolet light from an ultraviolet light-emitting diode, particularly ultraviolet light in the UV-A or UV-B region, and is suitable for producing electronic components. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention.

[0013] That is, the present invention includes, but is not limited to, the following inventions.

[0014] 1. A photocurable resin composition that can be cured by irradiation with ultraviolet light in the UV-A or UV-B region, comprising the following components (a) to (c): (a) 2-Methylene-1,3-dicarbonyl compounds (b) Ionic Photobase Generator (c) Photosensitizer Including, The 2-methylene-1,3-dicarbonyl compound is represented by the following formula (I): [ka] A compound containing at least one structural unit represented by The ionic photobase generator comprises the following anion (i) and cation (ii): (i) Formula (BAr 4-n X n ) - wherein each Ar is independently an unsubstituted or substituted C-C 10 each X is independently an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group; n is an integer of 0 to 2; when n=0, at least one Ar is a substituted C6-C 10 An anion represented by the aromatic hydrocarbon group (ii) a cation having an amidine structure, a guanidine structure or a biguanide structure A photocurable resin composition comprising a salt comprising:

[0015] 2. The photocurable resin composition according to item 1 above, wherein at least one Ar in the anion (i) is a substituted phenyl group.

[0016] 3. The photocurable resin composition according to item 2 above, wherein the substituted phenyl group has a substituent containing fluorine.

[0017] 4. The photocurable resin composition according to item 3 above, wherein the fluorine-containing substituent is bonded to a carbon atom that is at the meta position relative to the carbon atom directly bonded to the boron atom of the substituted phenyl group.

[0018] 5. The photocurable resin composition according to item 3 or 4 above, wherein the fluorine-containing substituent is a fluorine atom.

[0019] 6. The photocurable resin composition according to item 5 above, wherein each Ar in the anion (i) is a 3-fluorophenyl group.

[0020] 7. The photocurable resin composition according to item 1 above, wherein n in the anion (i) is 0 or 1.

[0021] 8. The photocurable resin composition according to item 7 above, wherein n is 0.

[0022] 9. The photocurable resin composition according to any one of items 1 to 8 above, wherein the ratio of the number of moles of component (c) to the number of moles of component (b) is 0.1 to 6. Effect of the Invention

[0023] The photocurable resin composition of the present invention contains a photobase generator having a specific structure together with a photosensitizer that can be excited by absorption of ultraviolet light in the UV-A or UV-B region. As a result, the photocurable resin composition of the present invention is quickly cured by anionic polymerization even when irradiated with ultraviolet light in the UV-A or UV-B region from an ultraviolet light-emitting diode, making it suitable for the manufacture of electronic parts. Furthermore, the resin composition of the present invention has excellent storage stability. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a cross-sectional view of a camera module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described in detail.

[0026] The photocurable resin composition of the present invention can be cured by irradiation with ultraviolet light in the UV-A or UV-B region, and contains the following components (a) to (c): (a) 2-Methylene-1,3-dicarbonyl compounds (b) Ionic Photobase Generator (c) Photosensitizer Here, the 2-methylene-1,3-dicarbonyl compound of component (a) is represented by the following formula (I): [ka] It is a compound containing at least one structural unit represented by the following formula: The ionic photobase generator of component (b) is a compound having the following anion (i) and cation (ii): (i) Formula (BAr 4-n X n ) - wherein each Ar is independently an unsubstituted or substituted C-C 10 each X is independently an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group; n is an integer of 0 to 2; when n=0, at least one Ar is a substituted C6-C 10 An anion represented by the aromatic hydrocarbon group (ii) a cation having an amidine structure, a guanidine structure or a biguanide structure It is a salt comprising: The components (a) to (c) will be described below.

[0027] [2-Methylene-1,3-dicarbonyl compound (component (a))] The 2-methylene-1,3-dicarbonyl compound (component (a)) used in the present invention is represented by the following formula (I): [ka] The component (a) contains one or more structural units of the formula (I). In one embodiment, the component (a) contains two to six, preferably two, structural units of the formula (I).

[0028] Since the 2-methylene-1,3-dicarbonyl compound contains the structural unit of formula (I), polymerization between the structural units occurs in the presence of an initiator, typically a basic substance (for example, a basic substance generated from an ionic photobase generator (component (b)) described below), and therefore it can be used as component (a) in the present invention. When the 2-methylene-1,3-dicarbonyl compound contains one having two or more structural units of formula (I) (a multifunctional component), crosslinking occurs during curing, and improvements in physical properties, such as improved mechanical properties at high temperatures of the cured product, can be expected.

[0029] Component (a) contains one or more 2-methylene-1,3-dicarbonyl compounds. The 2-methylene-1,3-dicarbonyl compounds contained in component (a) preferably have a molecular weight of 180 to 10,000, more preferably 180 to 5,000, even more preferably 180 to 2,000, even more preferably 220 to 2,000, even more preferably 200 to 1,500, even more preferably 240 to 1,500, even more preferably 250 to 1,500, particularly preferably 250 to 1,000, and most preferably 260 to 1,000. The molecular weight of the 2-methylene-1,3-dicarbonyl compound contained in component (a) and the weight content of the 2-methylene-1,3-dicarbonyl compound when the entire photocurable resin composition (or the entire 2-methylene-1,3-dicarbonyl compound in the photocurable resin composition) is taken as 1 can be determined, for example, by a reversed-phase high performance liquid chromatography (reverse-phase HPLC) method using an ODS column as a column and a mass spectrometer (MS) and PDA (detection wavelength: 190 to 800 nm) or ELSD as a detector. If the molecular weight of component (a) is less than 180, the vapor pressure at 25°C is too high, and various problems due to volatile substances may occur. In particular, if the volatile substances adhere to peripheral members, they are cured by the base on the surface, leading to contamination of the peripheral members. On the other hand, if the molecular weight of component (a) exceeds 10,000, the viscosity of the photocurable resin composition increases, workability decreases, and the amount of filler added is limited.

[0030] Component (a) may contain a polyfunctional component. Polyfunctionality refers to the fact that the 2-methylene-1,3-dicarbonyl compound contains two or more structural units of the formula (I). The number of structural units of the formula (I) contained in the 2-methylene-1,3-dicarbonyl compound is called the "functionality" of the 2-methylene-1,3-dicarbonyl compound. Among 2-methylene-1,3-dicarbonyl compounds, those with one functional group are called "monofunctional", those with two functional groups are called "bifunctional", and those with three functional groups are called "trifunctional". The cured product obtained by using component (a) containing a polyfunctional component is crosslinked, so that the physical properties of the cured product, such as heat resistance and mechanical properties at high temperatures, are improved. When a polyfunctional component is used, it is preferable that the weight ratio of the polyfunctional component is 0.01 or more when the entire photocurable resin composition of the present invention is taken as 1. In one embodiment, when the entire photocurable resin composition of the present invention is taken as 1, the weight ratio of component (a) containing two or more structural units represented by formula (I) is preferably 0.01 to 1.00, more preferably 0.05 to 0.95, even more preferably 0.05 to 0.90, particularly preferably 0.10 to 0.90, and most preferably 0.20 to 0.80.

[0031] When component (a) contains a polyfunctional component, the cured product forms a network-like crosslinked structure, and therefore does not flow even at high temperatures, particularly at temperatures above the glass transition temperature, and maintains a constant storage modulus. The storage modulus of the cured product at high temperatures can be evaluated, for example, by dynamic mechanical analysis (DMA). When a cured product that has formed a crosslinked structure is evaluated by DMA, a region in which the temperature change in the storage modulus is relatively small, called a plateau, is generally observed over a wide range above the glass transition temperature. The storage modulus in this plateau region is evaluated as a quantity related to the crosslink density, i.e., the content of the polyfunctional component in component (a).

[0032] In one embodiment, when the entire photocurable resin composition of the present invention is taken as 1, the weight proportion of component (a) is preferably 0.10 to 0.999, more preferably 0.20 to 0.995, and particularly preferably 0.50 to 0.99.

[0033] In one embodiment, the 2-methylene-1,3-dicarbonyl compound has the following formula (II): [ka] (In the formula, X 1 and X 2 each independently represents a single bond, O, or NR 3 (In the formula, R 3 represents hydrogen or a monovalent hydrocarbon group, R 1 and R 2 each independently represents a hydrogen atom, a monovalent hydrocarbon group, or a group represented by the following formula (III): [ka] (In the formula, X 3 and X 4 each independently represents a single bond, O, or NR 5 (In the formula, R 5 represents hydrogen or a monovalent hydrocarbon group, W represents a spacer; R 4 represents hydrogen or a monovalent hydrocarbon group. It is expressed as:

[0034] In one embodiment, the 2-methylene-1,3-dicarbonyl compound has the following formula (IV): [ka] (In the formula, R 1 and R 2 each independently represents a hydrogen atom, a monovalent hydrocarbon group, or a group represented by the following formula (V): [ka] (In the formula, W represents a spacer; R 4 represents hydrogen or a monovalent hydrocarbon group. It is expressed as:

[0035] In another embodiment, the 2-methylene-1,3-dicarbonyl compound has the following formula (VI): [ka] (In the formula, R 11 is represented by the following formula (VII): [ka] represents a 1,1-dicarbonylethylene unit represented by the formula: Each R 12 each independently represents a spacer, R 13 and R 14 each independently represents hydrogen or a monovalent hydrocarbon group, X 11 And each X 12 and X 13 each independently represents a single bond, O, or NR 15 (In the formula, R 15 represents hydrogen or a monovalent hydrocarbon group, Each m independently represents 0 or 1; n represents an integer between 1 and 20. It is a dicarbonylethylene derivative represented by the formula:

[0036] In this specification, the monovalent hydrocarbon group refers to a group generated by removing one hydrogen atom from a carbon atom of a hydrocarbon. Examples of the monovalent hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkyl-substituted cycloalkyl group, an aryl group, an aralkyl group, and an alkaryl group, some of which may contain heteroatoms such as N, O, S, P, and Si.

[0037] The monovalent hydrocarbon groups may each be substituted with alkyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, allyl, alkoxy, alkylthio, hydroxyl, nitro, amido, azido, cyano, acyloxy, carboxy, sulfoxy, acryloxy, siloxy, epoxy, or ester. The monovalent hydrocarbon group is preferably an alkyl group, a cycloalkyl group, an aryl group, or an alkyl group substituted with a cycloalkyl group, and more preferably an alkyl group, a cycloalkyl group, or an alkyl group substituted with a cycloalkyl group.

[0038] The number of carbon atoms of the alkyl group, alkenyl group, and alkynyl group (hereinafter collectively referred to as "alkyl group, etc.") is not particularly limited. The number of carbon atoms of the alkyl group is usually 1 to 18, preferably 1 to 16, more preferably 2 to 12, more preferably 3 to 10, and particularly preferably 4 to 8. The number of carbon atoms of the alkenyl group and alkynyl group is usually 2 to 12, preferably 2 to 10, more preferably 3 to 8, more preferably 3 to 7, and particularly preferably 3 to 6. When the alkyl group, etc. has a cyclic structure, the number of carbon atoms of the alkyl group, etc. is usually 5 to 16, preferably 5 to 14, more preferably 6 to 12, and more preferably 6 to 10. The number of carbon atoms of the alkyl group, etc. can be specified, for example, by the reversed-phase HPLC or nuclear magnetic resonance method (NMR method).

[0039] The structure of the alkyl group, etc. is not particularly limited. The alkyl group, etc. may be linear or may have a side chain. The alkyl group, etc. may have a chain structure or a cyclic structure (cycloalkyl group, cycloalkenyl group, and cycloalkynyl group). The alkyl group, etc. may have one or more other substituents. For example, the alkyl group, etc. may have a substituent containing an atom other than carbon atom and hydrogen atom as a substituent. In addition, the alkyl group, etc. may contain one or more atoms other than carbon atom and hydrogen atom in the chain structure or cyclic structure. Examples of the atom other than carbon atom and hydrogen atom include one or more of oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, and silicon atom.

[0040] Specific examples of the alkyl group include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, and 2-ethylhexyl. Specific examples of the cycloalkyl group include cyclopentyl, cyclohexyl, cycloheptyl, and 2-methylcyclohexyl. Specific examples of the alkenyl group include vinyl, allyl, and isopropenyl. Specific examples of the cycloalkenyl group include cyclohexenyl.

[0041] The 2-methylene-1,3-dicarbonyl compound is represented by the formula (II) or (IV), 1 and R 2 are both monovalent hydrocarbon groups, R 1 and R 2 is particularly preferably an alkyl group, a cycloalkyl group, an alkyl-substituted cycloalkyl group, an aryl group, an aralkyl group or an alkaryl group each having 2 to 8 carbon atoms.

[0042] In the present specification, the spacer refers to a divalent hydrocarbon group, and more specifically, a cyclic, linear or branched, substituted or unsubstituted alkylene group. The number of carbon atoms in the alkylene group is not particularly limited. The number of carbon atoms in the alkylene group is usually 1 to 12, preferably 2 to 10, more preferably 3 to 8, and further preferably 4 to 8. Here, the alkylene group may contain a group containing a heteroatom selected from N, O, S, P, and Si, as desired. In addition, the alkylene group may have an unsaturated bond. In one embodiment, the spacer is an unsubstituted alkylene group having 4 to 8 carbon atoms. Preferably, the spacer is a linear substituted or unsubstituted alkylene group, more preferably a group represented by the formula -(CH2) nIt is an alkylene group having a structure represented by the formula: - (wherein n is an integer of 2 to 10, preferably 4 to 8), and the carbon atoms at both ends thereof are bonded to the remaining portion of the 2-methylene-1,3-dicarbonyl compound. Specific examples of the divalent hydrocarbon group as the spacer include, but are not limited to, a 1,4-n-butylene group and a 1,4-cyclohexylenedimethylene group.

[0043] When the 2-methylene-1,3-dicarbonyl compound has a spacer, the number of carbon atoms in the terminal monovalent hydrocarbon group is preferably 6 or less. That is, when the 2-methylene-1,3-dicarbonyl compound is represented by the formula (II) or (IV), R 4 is preferably an alkyl group having 1 to 6 carbon atoms, provided that R 1 and R 2 When one of the formulas is represented by formula (III) or (V), R 1 and R 2 The other is preferably an alkyl group having 1 to 6 carbon atoms. In this case, in the formula (II) or (IV), R 1 and R 2 may be represented by the above formula (III) or formula (V), but preferably, R 1 and R 2 Only one of the above is represented by the formula (III) or the formula (V). Preferably, the 2-methylene-1,3-dicarbonyl compound is represented by the above formula (IV).

[0044] Particularly preferred compounds having a spacer include those represented by the formula (IV) 1 or R 2 one of which is an ethyl group, an n-hexyl group, or a cyclohexyl group, and the other is represented by the above formula (V), W is a 1,4-n-butylene group or a 1,4-cyclohexylenedimethylene group, and R 4 is an ethyl group, an n-hexyl group, or a cyclohexyl group. 1 and R 2is represented by the above formula (V), W is either a 1,4-n-butylene group or a 1,4-cyclohexylenedimethylene group, and R 4 is an ethyl group, an n-hexyl group, or a cyclohexyl group.

[0045] Various 2-methylene-1,3-dicarbonyl compounds are available from SIRRUS Inc., Ohio, USA, and their synthesis methods are disclosed in published patent publications such as WO2012 / 054616, WO2012 / 054633, and WO2016 / 040261. When both ends of the structural unit represented by the formula (I) contained in the 2-methylene-1,3-dicarbonyl compound are bonded to oxygen atoms, a known method such as ester exchange with a diol or polyol disclosed in JP-A-2015-518503 can be used to produce a 2-methylene-1,3-dicarbonyl compound having a larger molecular weight in which a plurality of structural units represented by the formula (I) are bonded via ester bonds and the spacer. The 2-methylene-1,3-dicarbonyl compound thus produced is a compound represented by the formula (II) or the formula (IV) R 1 and R 2 R in the formula (III) or (V) 4 and R in formula (VI) 14 and R 13 However, it may contain a hydroxy group. By appropriately mixing these 2-methylene-1,3-dicarbonyl compounds, it is possible to obtain the component (a) containing the 2-methylene-1,3-dicarbonyl compound.

[0046] Specific examples of 2-methylene-1,3-dicarbonyl compounds preferred as component (a) include dibutyl methylene malonate, dipentyl methylene malonate, dihexyl methylene malonate, dicyclohexyl methylene malonate, ethyl octyl methylene malonate, propyl hexyl methylene malonate, 2-ethylhexyl-ethyl methylene malonate, ethyl phenyl-ethyl methylene malonate, etc. These are preferred because they have low volatility and high reactivity. From the viewpoint of handling, dihexyl methylene malonate and dicyclohexyl methylene malonate are particularly preferred.

[0047] [Ionic photobase generator (component (b))] The photocurable resin composition of the present invention contains an ionic photobase generator (component (b)). A photobase generator is a compound capable of generating a basic substance by a chemical reaction in which light energy directly or indirectly participates. Component (b) in the present invention undergoes a chemical reaction by energy transmitted from a photosensitizer (component (c) described below) excited by absorbing ultraviolet light in the UV-A or UV-B region, thereby generating a basic substance. Photobase generators are broadly divided into ionic and non-ionic types, and an ionic photobase generator is used in the present invention. Component (b) is a type of latent initiator. That is, the basic substance generated from component (b) is expected to contribute as an initiator to the polymerization initiation reaction when component (a) in the photocurable resin composition is cured by Michael addition reaction. The compound used as component (b) in the present invention may be used alone or in combination of two or more kinds.

[0048] Component (b) is a compound having the following anion (i) and cation (ii): (i) Formula (BAr 4-n X n ) - wherein each Ar is independently an unsubstituted or substituted C-C 10each X is independently an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group; n is an integer of 0 to 2; when n=0, at least one Ar is a substituted C6-C 10 An anion represented by the aromatic hydrocarbon group (ii) a cation having an amidine structure, a guanidine structure or a biguanide structure It is a salt comprising:

[0049] Examples of Ar in the anion (i) include an unsubstituted or substituted phenyl group, an unsubstituted or substituted naphthyl group, an unsubstituted or substituted azulene group, and the like. Examples of X in the anion (i) include an unsubstituted or substituted C1-C6 alkyl group, an unsubstituted or substituted C3-C6 cycloalkyl group, an unsubstituted or substituted C2-C6 alkenyl group, and an unsubstituted or substituted C2-C6 alkynyl group.

[0050] In one embodiment, at least one Ar in the anion (i) is a substituted phenyl group. Preferably, the substituted phenyl group has a fluorine-containing substituent. Preferably, the fluorine-containing substituent is bonded to a carbon atom that is meta-positioned with respect to a carbon atom directly bonded to a boron atom of the substituted phenyl group. In this way, when the fluorine-containing substituent is present at the meta-position, the photocurable resin composition has excellent storage stability at room temperature. In one embodiment, the fluorine-containing substituent is a fluorine atom.

[0051] Preferably, each Ar in the anion (i) is a 3-fluorophenyl group. In the anion (i), n is preferably 0 or 1, and more preferably 0. As described above, when n=0, at least one of the four Ar in the anion (i) must have a substituent. In one embodiment, the anion (i) is a tetrakis(monohalophenyl)borate anion, such as a tetrakis(3-fluorophenyl)borate anion. In another embodiment, the anion (i) is a monoalkyltriphenylborate anion, such as n-butyltriphenylborate anion.

[0052] On the other hand, cation (ii) has an amidine structure, a guanidine structure, or a biguanide structure as described above. In this specification, "amidine structure", "guanidine structure", or "biguanide structure" refers to a cation structure formed by, for example, protonation, alkylation, or the like, of one or more nitrogen atoms in each neutral structure. That is, cation (ii) includes a cation derived from an amidine compound, a cation derived from a guanidine compound, or a cation derived from a biguanide compound. The amidine compound preferably has the following formula: [ka] (In the formula, R a , R b , R c and R d each independently represents a hydrogen atom, an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group, or an unsubstituted or substituted C6-C 10 is an aromatic hydrocarbon group, R a is R b , R c or R d may together with the carbon atom and nitrogen atom to which they are attached form a ring, R b is R c or R d may be taken together with the nitrogen atom to which they are attached and the carbon atom to which said nitrogen atom is attached to form a ring, R c is R d may form a ring together with the nitrogen atom to which they are attached). The compound is represented by R a , R b , R c and Rd Each of R is preferably an unsubstituted linear C1-C6 aliphatic hydrocarbon group, more preferably an unsubstituted linear C1-C4 aliphatic hydrocarbon group, and particularly preferably an unsubstituted linear C1-C3 aliphatic hydrocarbon group. a and R c , and R b and R d and each together form a ring, which is more preferable from the viewpoint of hydrolysis resistance. From the viewpoint of quick curing property, the molecular weight of the amidine compound is preferably 100 to 600, and more preferably 100 to 200.

[0053] The guanidine compound preferably has the following formula: [ka] (In the formula, R b , R c , R d , R e and R f each independently represents a hydrogen atom, an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group, or an unsubstituted or substituted linear, branched or cyclic C6-C 10 is an aromatic hydrocarbon group, R b is R c , R d , R e or R f may be taken together with the nitrogen atom to which they are attached and the carbon atom to which said nitrogen atom is attached to form a ring, R e and R f are each independently R c or R d may be taken together with the nitrogen atom to which they are attached and the carbon atom to which said nitrogen atom is attached to form a ring, R c is R d may together with the nitrogen atom to which they are attached form a ring, R e is Rf may form a ring together with the nitrogen atom to which they are attached). The compound is represented by R b , R c , R d , R e and R f Each of R is preferably an unsubstituted linear C1-C6 aliphatic hydrocarbon group, more preferably an unsubstituted linear C1-C4 aliphatic hydrocarbon group, and particularly preferably an unsubstituted linear C1-C3 aliphatic hydrocarbon group. b , R c , R d , R e and R f If two or more of the groups form a ring, R c and R e , and R b and R d and preferably combine together to form a ring. From the viewpoint of quick curing properties, the molecular weight of the guanidine compound is preferably 100-600, and more preferably 100-300.

[0054] The biguanide compound preferably has the formula: [ka] (In the formula, R b , R c , R d , R g , R h , R i and R j each independently represents a hydrogen atom, an unsubstituted or substituted linear, branched or cyclic C1-C6 aliphatic hydrocarbon group, or an unsubstituted or substituted linear, branched or cyclic C6-C 10 (aromatic hydrocarbon group) The compound is represented by R b , R c , R d , R g , R h , R i and R jare each preferably an unsubstituted linear or cyclic C1-C6 aliphatic hydrocarbon group. From the viewpoint of quick curing property, the molecular weight of the biguanide compound is preferably 100 to 500, more preferably 110 to 400, and particularly preferably 150 to 350. For the same reason, R in the biguanide compound b , R c , R d , R g , R h , R i and R j Among these, the number of those having 6 or more carbon atoms is preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less.

[0055] The amidine compounds, guanidine compounds and biguanide compounds are all uncharged neutral molecules and therefore are not the structures of cations (ii) themselves. However, these neutral molecules can undergo structural modifications obvious to those skilled in the art, such as protonation and alkylation, to form cations. In this specification, "cations having an amidine structure", "cations having a guanidine structure" and "cations having a biguanide structure" respectively refer to cations generated by such structural modifications of the amidine compounds, guanidine compounds and biguanide compounds.

[0056] In one embodiment, the cation (ii) is a cation having an amidine structure, such as a cation derived from 1,8-diazabicyclo[5.4.0]undecene (DBU) or 1,5-diazabicyclo[4.3.0]nonene (DBN). In another embodiment, cation (ii) is a cation having a guanidine structure, such as 1,1,3,3-tetramethylguanidine (TMG) or a cation derived from 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). In another embodiment, cation (ii) is a cation having a biguanide structure (particularly R c is a hydrogen atom, and R b , R d , R g , R h , Ri and R j are alkyl groups), such as 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanide, or a cation derived from (Z)-{[bis(dimethylamino)methylidene]amino}-N-cyclohexyl(cyclohexylamino)methanimine. In some embodiments, such cation (ii) has a pK a Since it generates a strong base with a molecular weight of 12 or more, it is advantageous from the viewpoint of quick curing.

[0057] The component (b) used in the present invention is a salt containing the above anion (i) and cation (ii).

[0058] Specific examples of component (b) include, but are not limited to, a salt containing protonated DBU and tetrakis(3-fluorophenyl)borate anion, a salt containing benzylated DBU and tetrakis(3-fluorophenyl)borate anion, WPBG-300 (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), WPBG-345 (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), tetramethylguanidinium tetrakis(3-fluorophenyl)borate, and tetramethylguanidinium tetrakis(4-fluorophenyl)borate.

[0059] In the present invention, the content of component (b) is preferably 0.01 mol% to 30 mol%, more preferably 0.01 mol% to 10 mol%, based on the total amount (100 mol%) of the 2-methylene-1,3-dicarbonyl compound (component (a)) in the photocurable resin composition. If the content of component (b) is less than 0.01 mol%, the curing becomes unstable. Conversely, if the content of component (b) is more than 30 mol%, a large amount of basic substances (generated from component (b)) that do not form chemical bonds with the resin matrix remain in the cured product, and the mechanical strength of the cured product may decrease.

[0060] [Photosensitizer (ingredient (c))] The photocurable resin composition of the present invention contains a photosensitizer (component (c)). In general, a photosensitizer refers to a compound that is excited by the absorption of light and can transfer the excitation energy to another substance to cause a chemical reaction in the substance without causing a chemical reaction itself. In the present invention, a photosensitizer is used that can be excited by the absorption of ultraviolet light in the UV-A or UV-B region to cause the above reaction. In this specification, the terms "UV-A" and "UV-B" are used according to the definitions of the International Commission on Illumination. That is, "UV-A" refers to ultraviolet light having a wavelength of 315 to 400 nm. "UV-B" refers to ultraviolet light having a wavelength of 280 to 315 nm. In addition, in this specification, "UV-A" and "UV-B" may be referred to as ultraviolet light in the UV-A region and ultraviolet light in the UV-B region, respectively, according to convention. In some embodiments, the photosensitizer is excited by ultraviolet light with a wavelength of 365 nm. In the present invention, component (c) is different from component (b). In addition, the photosensitizer of component (c) is not covalently bonded to the ionic photobase generator of component (b). This increases the freedom of formulation design, and allows the amount of component (c) to be appropriately selected. The photosensitizer may be used alone or in combination of two or more kinds.

[0061] Component (c) is not particularly limited as long as it is a photosensitizer that can be excited by absorbing ultraviolet light in the UV-A or UV-B region and can induce component (b) to generate a basic substance by transferring a part or all of the excitation energy to component (b). Component (c) is preferably a photosensitizer that can be excited by absorbing ultraviolet light in the UV-A region and can induce the above reaction. Examples of component (c) include anthraquinone, naphthoquinone, quinone, thioxanthone, acridone, benzoyldiphenylphosphine oxide, 1,2-diketone, phenothiazine, ketocoumarin, fluorene, naphthiazoline, biacetyl, benzyl and derivatives thereof, perylene, and substituted anthracene. More specific examples of component (c) include 2-ethylanthraquinone, 2-isopropylthioxanthone, 4-benzoyl-4'-methyldiphenyl sulfide, and the like. The component (c) is preferably anthraquinone, naphthoquinone, quinone, thioxanthone, or a derivative thereof, and from the viewpoint of immediate curing properties, more preferably anthraquinone or a derivative thereof.

[0062] The photocurable resin composition of the present invention contains preferably 0.01 to 10 wt %, more preferably 0.05 to 5 wt %, and even more preferably 0.1 to 3 wt % of component (c) based on the total weight of the photocurable resin composition. Also preferably, the ratio of the number of moles of component (c) to the number of moles of component (b) is 0.1 to 6. If the amount of component (c) is too small, curing may not occur sufficiently. On the other hand, if the amount of component (c) is too large, the irradiated ultraviolet light may be mostly absorbed by the surface of the photocurable resin composition, and curing may not occur sufficiently inside the photocurable resin composition. The ratio of the number of moles of component (c) to the number of moles of component (b) is more preferably 0.1 to 4, even more preferably 0.1 to 2, particularly preferably 0.1 to 1, and most preferably 0.1 to 0.99. In the present invention, unlike the photobase generator disclosed in, for example, Patent Document 4, the desired curing speed and physical properties of the cured product can be obtained by appropriately adjusting the blending ratio of components (b) and (c) in the photocurable resin composition. In particular, in one embodiment of the present invention, the photocurable resin composition exhibits sufficient instantaneous curing properties even when the ratio of the number of moles of component (c) to the number of moles of component (b) is greater than 1.

[0063] The photocurable resin composition of the present invention can be cured in a short time at room temperature by being exposed to a sufficient cumulative amount of ultraviolet light in the UV-A or UV-B region. In one embodiment of the present invention, the irradiation intensity is 100 to 10,000 mW / cm. 2 is preferably 1000 to 9000 mW / cm 2 In one embodiment of the present invention, the photocurable resin composition can be cured at room temperature by receiving ultraviolet light having a wavelength of 315 to 400 nm (UV-A), preferably 340 to 400 nm, and more preferably 350 to 380 nm. In another embodiment of the present invention, the photocurable resin composition can be cured at room temperature by receiving ultraviolet light from a gallium nitride UV-LED. In one embodiment of the present invention, the integrated light amount of ultraviolet light received by the photocurable resin composition is preferably 200 mJ / cm. 2 More preferably, 1000 mJ / cm 2 More preferably, it is 2000 mJ / cm 2 More preferably, it is 3000 mJ / cm 2 That is all. There is no particular limit to the upper limit of the cumulative light amount, and it can be freely set within a range that does not impair the gist of the present invention. The cumulative light amount of ultraviolet light in the UV-A or UV-B region can be measured using measuring instruments commonly used in the relevant field, such as an ultraviolet integrating light meter and a light receiver. For example, the cumulative light amount in the ultraviolet wavelength region (310 to 390 nm) with a central wavelength of 365 nm can be measured using an ultraviolet integrating light meter (UIT-250, manufactured by Ushio Inc.) and a light receiver (UVD-S365, manufactured by Ushio Inc.).

[0064] In one embodiment of the present invention, the photocurable resin composition has excellent storage stability. The photocurable resin composition of the present invention is stable in storage for preferably 24 hours or more, more preferably one week or more, and even more preferably one month or more. Here, the "storage state" refers to an environment at room temperature, with a humidity of 50%±10%, and where ultraviolet rays are cut off. In addition, "stable" refers to a state in which curing has progressed and the composition has practically lost fluidity.

[0065] In one embodiment of the present invention, the photocurable resin composition cures rapidly and reliably not only when component (a) is highly reactive (e.g., diethyl methylene malonate) but also when it is difficult to react due to steric hindrance or the like (e.g., a monomer having a large molecular weight such as dihexyl methylene malonate).

[0066] In addition to the components (a) to (c), the photocurable resin composition of the present invention may contain, as necessary, a stabilizer, an insulating or conductive filler, an interface treatment agent such as a coupling agent, a pigment, a plasticizer, a flame retardant, an ion trapping agent, an antifoaming agent, a leveling agent, a foam breaker, and the like.

[0067] The photocurable resin composition of the present invention contains the above-mentioned components (a) to (c), and, if necessary, the above-mentioned stabilizer and other components. The photocurable resin composition of the present invention can be prepared by mixing these components. A known device can be used for mixing. For example, mixing can be performed using a known device such as a Henschel mixer or a roll mill. These components may be mixed simultaneously, or some of them may be mixed first and the rest may be mixed later.

[0068] The photocurable resin composition of the present invention can be used as a one-liquid adhesive, particularly as a one-liquid adhesive for electronic components. Specifically, the photocurable resin composition of the present invention is suitable for bonding and sealing electronic components, or for structurally reinforcing electronic components by filling gaps between electronic components. More specifically, the photocurable resin composition of the present invention can be used for bonding and sealing or reinforcing camera module components, and is particularly suitable for bonding image sensor modules. In the present invention, electronic components bonded using the photocurable resin composition of the present invention are also provided. In addition, electronic components sealed using the photocurable resin composition of the present invention are also provided. Furthermore, electronic components reinforced using the photocurable resin composition of the present invention are also provided. The photocurable resin composition of the present invention can also be used as an insulating composition or a conductive composition. The photocurable resin composition of the present invention may be used for permanent bonding and sealing or reinforcement, or may be used for temporary bonding and sealing or reinforcement.

[0069] For example, as shown in FIG. 1, the photocurable resin composition of the present invention can be used to bond an IR cut filter 20 to a printed wiring board 24. The photocurable resin composition of the present invention can be used to bond an imaging element 22 to a printed wiring board 24. The photocurable resin composition of the present invention can be used to bond a support 18 to a printed wiring board 24. A jet dispenser, an air dispenser, or the like can be used to supply the photocurable resin composition to the surface to be bonded. The photocurable resin composition of the present invention can be cured by irradiating it with UV-A or UV-B at room temperature. The irradiation time is, for example, 0.01 seconds to 1 minute.

[0070] The photocurable resin composition of the present invention can also be used in image sensor modules other than camera modules. For example, it can be used for bonding, sealing, or reinforcing parts of image sensor modules that may be incorporated in fingerprint authentication devices, face authentication devices, scanners, medical devices, etc.

[0071] The photocurable resin composition of the present invention can also be used as a constituent material of a film. In particular, the photocurable resin composition of the present invention is suitable as a constituent material of a coverlay film for protecting a wiring pattern or an interlayer adhesive film for a multilayer wiring board. This is because the photocurable resin composition of the present invention is cured by anionic polymerization, and is therefore less susceptible to oxygen inhibition. In addition, a film containing the photocurable resin composition of the present invention can be preferably used for electronic parts. The film containing the photocurable resin composition of the present invention can be obtained from the photocurable resin composition of the present invention by a known method. For example, the photocurable resin composition of the present invention can be applied to at least one surface of a support to provide a film attached to the support or a film peeled off from the support. EXAMPLES

[0072] Examples and comparative examples of the present invention will be described below. The present invention is not limited to the following examples and comparative examples. In the following examples and comparative examples, the proportions of components contained in the photocurable resin composition are shown in parts by weight.

[0073] [Preparation of photocurable resin composition] The raw materials of the photocurable resin compositions used in the following Examples and Comparative Examples are as follows. 2-Methylene-1,3-dicarbonyl compounds (component (a)): (a-1) DHMM (SIRRUS, Chemilian TM L3000 XP) (a-2) DCHMM (SIRRUS, Chemilian TM H4000 XP) The specific structure of the above 2-methylene-1,3-dicarbonyl compound is as shown in the chemical formula in Table 1 below. [Table 1]

[0074] Photobase generator (component (b)): (b-1) (Z)-{[bis(dimethylamino)methylidene]amino}-N-cyclohexyl(cyclohexylamino)methaniminium tetrakis(3-fluorophenyl)borate (WPBG-345, Fujifilm Wako Pure Chemical Industries, Ltd.) (b-2) 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenylborate (WPBG-300, Fujifilm Wako Pure Chemical Industries, Ltd.)

[0075] (b-3) Benzyl-1,8-diazabicyclo[5.4.0]-7-undecenium tetrakis(3-fluorophenyl)borate The following precursor-1 (282 mg, 0.681 mmol) was dissolved in pure water, and the following precursor-2 (200 mg, 0.619 mmol) was added dropwise to the resulting aqueous solution at room temperature while stirring, and the mixture was stirred for 2 hours. The resulting reaction mixture was separated into a chloroform layer and an aqueous layer, the aqueous layer was extracted with chloroform, and the resulting extract was combined with the chloroform layer. The resulting chloroform solution was washed three times with saturated saline, dried over sodium sulfate, filtered, and concentrated under reduced pressure to obtain 360 mg of the target product as a light brown oily substance. 1 H-NMR (CDCl3): δ7.40-7.33 (m, 3H), 7.16-7.09 (m, 4H), δ7.07-6.92 (m, 10H), 6.65-6.56 (m, 4H), 4.30 (s, 2H), 3.19-3.13 (m, 2H), 3.07-3.00 (m, 4H), 2.60-2.52 (m, 2H), 1.79-1.33 (m, 8H)

[0076] (b-4) 1,8-Diazabicyclo[5.4.0]-7-undecenium tetrakis(3-fluorophenyl)borate DBU (San-Apro, 83.6 mg, 0.549 mmol) was dissolved in acetone (2 mL), and the resulting solution was neutralized with 0.5 N hydrochloric acid (1.10 mL, 0.549 mmol). An aqueous solution of the following Precursor-1 (250 mg, 0.604 mmol) was added dropwise to the resulting mixture at room temperature while stirring. An oily substance formed in the resulting mixture was separated and dissolved in chloroform, and the resulting solution was stirred at room temperature for 2 hours. The resulting reaction mixture was diluted with chloroform. The resulting chloroform solution was washed with water, then washed three times with saturated saline, dried over sodium sulfate, filtered, and concentrated under reduced pressure to obtain 221 mg of the target product as a white solid. 1 H-NMR (CDCl3): δ7.20-7.14 (m, 4H), 7.10-6.98 (m, 8H), 6.67-6.58 (m, 4H), 4.95 (s, 1H), 3.19-3.13 (m, 2H), 3.07-3.00 (m, 2H), 2.60-2.52 (m, 2H), 1.89-1.83 (m, 2H), 1.64-1.37 (m, 8H)

[0077] (b-5) Tetramethylguanidinium tetrakis(3-fluorophenyl)borate Tetramethylguanidine (75.8 mg, 0.658 mmol) was dissolved in acetone, and the resulting solution was neutralized with 0.5N hydrochloric acid (1.32 mL, 0.658 mmol). An aqueous solution of the following Precursor-1 (300 mg, 0.724 mmol) was added dropwise to the resulting mixture. An oily substance formed in the resulting mixture was separated and dissolved in chloroform, and the resulting solution was stirred at room temperature for 4 hours. The resulting reaction mixture was diluted with chloroform. The resulting chloroform solution was washed with water, then washed three times with saturated saline, dried over sodium sulfate, filtered, and concentrated under reduced pressure to obtain 274.8 mg of the target product as a white solid. 1 H-NMR (DMSO-d6): δ7.76 (s, 2H), 7.10-6.88 (m, 8H), 6.86-6.58 (m, 8H), 2.87 (s, 12H)

[0078] (b-6) Tetramethylguanidinium tetrakis(4-fluorophenyl)borate Tetramethylguanidine (79.5 mg, 0.690 mmol) was dissolved in acetone, and the resulting solution was neutralized with 0.5N hydrochloric acid (1.38 mL, 0.690 mmol). An aqueous solution of tetrakis(4-fluorophenyl)borate sodium salt dihydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (300 mg, 0.724 mmol) was added dropwise to the resulting mixture. An oily substance formed in the resulting mixture was separated and dissolved in chloroform, and the resulting solution was stirred at room temperature for 4 hours. The resulting reaction mixture was diluted with chloroform. The resulting chloroform solution was washed with water, then washed three times with saturated saline, dried over sodium sulfate, filtered, and concentrated under reduced pressure to obtain 283.7 mg of the target product as a white solid. 1 H-NMR (DMSO-d6): δ7.75 (s, 2H), 7.11-7.00 (m, 8H), 6.80-6.68 (m, 8H), 2.87 (s, 12H)

[0079] Photobase generator (component (b')): (b-1') 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidinium 2-(3-benzoylphenyl)propionate (WPBG-266, Fujifilm Wako Pure Chemical Industries, Ltd.) (b-2') 8-(9-oxo-9H-thioxanthen-2-yl)methyl-1,8-diazabicyclo[5.4.0]-7-undecenium tetraphenylborate It was synthesized according to the method described in JP 2017-36361 A.

[0080] (b-3') 8-(9-oxo-9H-thioxanthen-2-yl)methyl-1,8-diazabicyclo[5.4.0]-7-undecenium tetrakis(3-fluorophenyl)borate The following precursor-1 (190 mg, 0.459 mmol) was dissolved in pure water, and the following precursor-3 (200 mg, 0.437 mmol) was added dropwise to the resulting aqueous solution at room temperature while stirring, and the mixture was stirred overnight. The resulting reaction mixture was separated into a chloroform layer and an aqueous layer, the aqueous layer was extracted with chloroform, and the resulting extract was combined with the chloroform layer. The resulting chloroform solution was washed three times with saturated saline, dried over sodium sulfate, filtered, and concentrated under reduced pressure to obtain 270 mg of the target product as a pale yellow solid. 1 H-NMR(CDCl3): δ8.58 (d, 8.4 Hz, 1H), 8.15 (s, 1H), 7.70-7.48 (m, 4H), 7.20-6.94 (m, 13H), 6.66-6.56 (m, 4H), 4.30 (s, 2H), 3.36-3.26 (m, 2H), 3.21-3.03 (m, 4H), 2.48-2.37 (m, 2H), 1.91-1.79 (m, 2H), 1.72-1.39 (m, 6H)

[0081] (b-4') 8-benzyl-1,8-diazabicyclo[5.4.0]-7-undecenium tetraphenylborate (U-CAT 5002, San-Apro Co., Ltd.)

[0082] (b-5') Dibenzoylferrocene (Fujifilm Wako Pure Chemical Industries, Ltd.) (b-6') Tributylammonium tetraphenylborate Tributylamine (487 mg, 2.63 mmol) was dissolved in acetone (6 mL), and the resulting solution was neutralized with 0.5 N hydrochloric acid (5.26 mL, 2.63 mmol). An aqueous solution of sodium tetraphenylborate (1.00 g, 2.92 mmol) was added dropwise to the resulting mixture. The resulting mixture was stirred at room temperature for 1 hour, and the crystals formed in the resulting reaction mixture were filtered, washed with pure water, and dried to obtain 1.18 g of the target product as white crystals. 1H-NMR (DMSO-d6): δ8.85 (s, 1H), 7.23-7.13 (m, 8H), 6.98-6.88 (m, 8H), 6.83-6.74 (m, 4H), 3.09-2.95 (m, 6H), 1.63-1.50 (m, 6H), 1.38-1.24 (m, 6H), 0.91 (t 7.2Hz, 9H)

[0083] (b-7') 2-(Piperidine-1-carbonyl)benzaldehyde (ENAMINE Ltd. Catalog No. EN300-6736678) Incidentally, 2-(piperidine-1-carbonyl)benzaldehyde is the same compound as PBG1 in Production Example 1 of Patent Document 1, that is, "2-(1-piperidinylcarbonyl)benzaldehyde."

[0084] (b-8') Tetramethylguanidinium tetraphenylborate Tetramethylguanidine (160 mg, 1.39 mmol) was dissolved in acetone, and the resulting solution was neutralized with 0.5N hydrochloric acid (2.78 mL, 1.39 mmol). An aqueous solution of sodium tetraphenylborate (500 mg, 1.46 mmol) was added dropwise to the resulting mixture. The resulting mixture was stirred at room temperature for 4 hours, and the crystals formed in the resulting reaction mixture were filtered, washed with pure water, and dried to obtain 544 mg of the target product as white crystals. 1 H-NMR (DMSO-d6): δ7.75 (s, 2H), 7.22-7.13 (m, 8H), 6.96-6.87 (m, 8H), 6.83-6.74 (m, 4H), 2.87 (s, 12H)

[0085] Photoradical generator (component (b")): (b-1") 2-Methyl-4'-(methylthio)-2-morpholinopropiophenone (Omnirad 907, Fujifilm Wako Pure Chemical Industries, Ltd.) (b-2") 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO, manufactured by IGM Resins BV)

[0086] Precursor-1, Precursor-2 and Precursor-3 were each synthesized by the following method. Precursor-1 (Sodium tetrakis(3-fluorophenyl)borate) It was synthesized according to the method described in the following document. Journal of the American Chemical Society, (2010), 132(38), 13168-13169

[0087] Precursor-2 (benzyl-1,8-diazabicyclo[5.4.0]-7-undecenium bromide) It was synthesized according to the method described in JP 2014-97930 A.

[0088] Precursor-3 (8-(9-oxo-9H-thioxanthen-2-yl)methyl-1,8-diazabicyclo[5.4.0]-7-undecenium bromide) It was synthesized according to the method described in JP 2017-36361 A.

[0089] Photosensitizer (ingredient (c)): (c-1) 2-Ethylanthraquinone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (c-2) 2-Isopropylthioxanthone (Tokyo Chemical Industry Co., Ltd.) (c-3) 4-Benzoyl-4'-methyldiphenyl sulfide (Tokyo Chemical Industry Co., Ltd.)

[0090] [Examples 1 to 9 and Comparative Examples 1 to 12] The photocurable resin composition was prepared in a room with a temperature of 22° C. and a humidity of 50%±10%, where light with a wavelength of 500 nm or less (including ultraviolet light) was blocked. In a screw cap bottle (light-shielding brown bottle) made of borosilicate glass, components (b), (b') or (b") and component (c) were added to 2 g of component (a) so that the weight ratios to component (a) were values ​​shown in Tables 2 to 4, and a mixture was obtained while performing ultrasonic dispersion for a maximum of 3 hours. When it was judged by visual inspection that a homogeneous solution had been obtained by the above operations, the obtained solution was used as a photocurable resin composition. When it was judged by visual inspection that a homogeneous solution was not obtained by the above operations, a centrifugation operation was carried out, and the supernatant was used as a photocurable resin composition.

[0091] In the examples and comparative examples, the properties of the photocurable resin compositions were measured as follows.

[0092] (Storage Stability of Photocurable Resin Composition) The photocurable resin composition thus produced was placed in a screw cap bottle (light-shielding brown bottle) made of borosilicate glass, and the time until it substantially lost fluidity (storage stability (hours)) was measured in a room at a temperature of 22°C±5°C and a humidity of 50%±10%, where light with a wavelength of 500 nm or less (including ultraviolet light) was blocked. The results are shown in Tables 2 to 4. The storage stability is preferably 24 hours or more, more preferably one week or more, and even more preferably one month or more. In this specification, "effectively loses fluidity" refers to a state in which the photocurable resin composition, filled to approximately half its volume in the borosilicate glass screw-top bottle (light-resistant brown bottle), undergoes no apparent change in shape for 10 seconds under gravity when the borosilicate glass screw-top bottle (light-resistant brown bottle) is instantly tilted from an upright position to horizontal.

[0093] (Instant curing of photocurable resin composition) In a room with a temperature of 22°C ± 5°C and humidity of 50% ± 10%, where light with a wavelength of 500 nm or less (including ultraviolet light) was cut off, a drop (approximately 0.02 g) of the photocurable resin composition was placed on a slide glass, and the composition was exposed to ultraviolet light with a wavelength of 365 nm using a single-wavelength UV LED light source (OmniCure® AC475, manufactured by Excelitas Technologies) with an accumulated light intensity of 4000 mJ / cm. 2(Measured with an ultraviolet integrating light meter UIT-250 and a receiver UVD-S365 (manufactured by Ushio Inc.)) the light source was continuously irradiated at a height of 4 cm from the top surface of the slide glass to the light source and at a light source moving speed of 9 mm / s, and the time (delay time) from the completion of irradiation to the curing of the photocurable resin composition was measured. The results (delay time) are shown in Tables 2 to 4. In this test, the photocurable resin composition was considered to be cured when no obvious change was observed in the shape of the photocurable resin composition on the slide glass when the slide glass was held vertically and subjected to gravity for 10 seconds. When the photocurable resin composition was judged to have cured by the above observation immediately after completion of irradiation, the delay time was recorded as "none." When the photocurable resin composition cured within 2 hours after the completion of irradiation, the time required from the completion of irradiation to curing was recorded. If the photocurable resin composition did not cure within 2 hours after the completion of irradiation, it was appropriately observed intermittently thereafter for up to 48 hours, and the time required from the completion of irradiation until it was confirmed that the photocurable resin composition had cured was recorded. If the photocurable resin composition did not cure within 48 hours after completion of irradiation, the delay time was recorded as "not cured." The delay time is preferably within 1 hour, more preferably within 30 minutes, even more preferably within 10 minutes, and most preferably within a few seconds.

[0094] [Table 2] [Table 3] [Table 4]

[0095] (Discussion of results) From Examples 1 to 12, it can be seen that the photocurable resin composition containing the above components (b) and (c) can achieve instantaneous curing with low-energy ultraviolet light having a wavelength of 365 nm even when the above component (a) is a 2-methylene-1,3-dicarbonyl compound (or a combination of two or more types) that is relatively difficult to cure, such as DHMM. This is partly because the basic substance generated from the above component (b) has a pK a This is because the photocurable resin composition containing the above components (b) and (c) is a strong base having a molecular weight of 12 or more. In addition, the photocurable resin composition containing the above components (b) and (c) exhibits excellent stability. This indicates that the curing of the photocurable resin composition of the present invention does not substantially proceed in the dark. From Example 2, the anion (i) of component (b) is represented by the formula (BAr 4-n X n ) - It can be seen that even if n is not 0, the photocurable resin composition can have sufficient instantaneous curing properties and stability.

[0096] On the other hand, Comparative Examples 1 to 12 show that when a photobase generator (component (b')) or a photoradical generator (component (b")) that does not correspond to the above-mentioned component (b) is used, the photocurable resin composition does not have immediate curability or stability. [Industrial Applicability]

[0097] The photocurable resin composition of the present invention is suitable for the production of electronic components because it is rapidly cured by anionic polymerization even when irradiated with ultraviolet light from a UV-LED, particularly UV-A or UV-B. Furthermore, the resin composition of the present invention has excellent storage stability. [Explanation of symbols]

[0098] 10 Camera Module 12 Lenses 14 Voice coil motor 16 Lens unit 18 Support 20 Cut Filter 22 Image sensor 24 Printed wiring board 30, 32, 34 Adhesive

[0099] The disclosure of Japanese Patent Application No. 2020-048080 (filing date: March 18, 2020) is incorporated herein by reference in its entirety. All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A photocurable resin composition that can be cured by irradiation with ultraviolet light in the UV-A or UV-B region, comprising the following components (a) to (c): (a) 2-methylene-1,3-dicarbonyl compounds (b) Ionic Photobase Generator (c) photosensitizer Including, The 2-methylene-1,3-dicarbonyl compound is represented by the following formula (I): 【Chemistry 13】 A compound containing at least one structural unit represented by The ionic photobase generator comprises the following anion (i) and cation (ii): (i) Formula (BAr ４－ｎ X ｎ ) － wherein each Ar is independently unsubstituted or substituted C ６ -C １０ Each X is independently an unsubstituted or substituted linear, branched or cyclic C １ -C ６ an aliphatic hydrocarbon group, n is an integer of 0 to 2, and when n=0, at least one Ar is a substituted C ６ -C １０ An anion represented by the formula (I) (ii) a cation having an amidine structure, a guanidine structure or a biguanide structure A salt comprising The photocurable resin composition, wherein the photosensitizer is different from the ionic photobase generator.

2. The photocurable resin composition according to claim 1, wherein at least one Ar in the anion (i) is a substituted phenyl group.

3. The photocurable resin composition according to claim 2, wherein the substituted phenyl group has a substituent containing fluorine.

4. 4. The photocurable resin composition according to claim 3, wherein the fluorine-containing substituent is bonded to a carbon atom that is meta to a carbon atom directly bonded to the boron atom of the substituted phenyl group.

5. 5. The photocurable resin composition according to claim 3, wherein the fluorine-containing substituent is a fluorine atom.

6. The photocurable resin composition according to claim 5, wherein each Ar in the anion (i) is a 3-fluorophenyl group.

7. 2. The photocurable resin composition according to claim 1, wherein n in the anion (i) is 0 or 1.

8. The photocurable resin composition according to claim 7, wherein n is 0.

9. 9. The photocurable resin composition according to claim 1, wherein the ratio of the number of moles of component (c) to the number of moles of component (b) is 0.1 to 6.

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