Curable silicone composition and its cured product

Abstract

The present invention provides a curable silicone composition. The curable silicone composition comprises (A) an organopolysiloxane containing an average of two or more alkenyl groups, (B) a crosslinking agent having an average of three or more mercapto groups, (C) an epoxy-functional silicone resin having monovalent aromatic hydrocarbon groups, (D) an epoxy-functional silicone, (E) an iodonium salt type cationic photoinitiator, and (F) a cationic photoinitiator other than component (E). According to this disclosure, a silicone-epoxy hybrid material can be provided that has the advantages of both silicone and organic epoxy and has excellent reliability and adhesion suitable for applications in the electronic display market.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority and all interests of U.S. Provisional Patent Application No. 63 / 524,263, filed on 30 June 2023, the contents of which are incorporated herein by reference.

[0002] (Field of invention) This invention relates to a curable silicone composition and its cured product. [Background technology]

[0003] Silicone-based materials are known to exhibit high flexibility, processability, and thermal reliability, but have low surface hardness and adhesive properties. Organic epoxy materials are known to have the opposite properties.

[0004] The preparation of silicone-epoxy hybrid materials has been demonstrated in efforts to combine the advantages of both. For example, International Publication WO2022 / 072271(A1) describes the preparation and formulation of a UV radiation-curable silicone-epoxy hybrid resin that provides preferred excellent adhesion and performance reliability in the display market. However, International Publication WO2022 / 072271(A1) did not address the applicability of silicone-epoxy in B-stage applications, which require initial UV curing to bring about a B-stage that enables good processability, followed by a final thermal curing. International Publication WO2022 / 072271(A1) addresses this problem by combining orthogonal curing chemistry, i.e., thiol-ene UV curing, with silicone-epoxy thermal curing (by using HAG instead of PAG) to achieve stepwise B-stage and C-stage curing. [Prior art documents] [Patent Documents]

[0005] Patent Document 1: International Publication No. WO2022 / 072271(A1) [Overview of the project] [Problems that the invention aims to solve]

[0006] Silicone-epoxy hybrid materials can be cured by both UV irradiation and heat by using different types of acid generators, namely photoacid generators (PAGs) and heatacid generators (HAGs). The object of the present invention is to provide a silicone-epoxy hybrid material that possesses the advantages of both silicone and organic epoxy, and has excellent reliability and adhesion suitable for applications in the electronic display market. [Means for solving the problem]

[0007] The curable silicone composition of the present invention, (A) An organopolysiloxane containing an average of two or more alkenyl groups represented by the following general formula,

[0008] [ka] In the formula, R 1 and R 8 However, each independently represents a C2-30 alkenyl group, R 2 ~R 7 However, each independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, and "n" is an integer from 0 to 100, and is an organopolysiloxane. (B) A crosslinking agent having an average of 3 or more mercapto groups represented by the following general formula,

[0009] [ka] In the formula, R 9 However, each independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, R10 each independently represents a C1-30 divalent aliphatic hydrocarbon group or a C6-30 divalent aromatic hydrocarbon group, and R 11 each independently represents a mercapto group or a C1-6 alkyl group, provided that at least three of R 11 are mercapto groups, a crosslinking agent, and (C) an epoxy-functional silicone resin represented by the following average unit formula: (R 12 3SiO 1 / 2 ) a (R 12 2SiO 2 / 2 ) b (R12SiO3 / 2 ) c (SiO 4 / 2 ) d In the formula, R 12 each independently represents a C1-6 monovalent aliphatic hydrocarbon group, a C6-10 monovalent aromatic hydrocarbon group, or a monovalent epoxy-substituted organic group, provided that at least about 15 mol% of all R 12 are C6-10 monovalent aromatic hydrocarbon groups, and "a", "b", "c", and "d" are numbers satisfying the conditions of 0 ≦ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≦ d < 0.4, 0.1 ≦ b / c ≦ 0.6, and a + b + c + d = 1, and about 2 to about 30 mol% of all siloxane units have a monovalent epoxy-substituted organic group, an epoxy-functional silicone resin, and (D) an epoxy-functional silicone represented by the following general formula: X 1 -R 13 2SiO(SiR 13 2O) m SiR 13 2-X 1 In the formula, R 13 each independently represents a C1-6 monovalent aliphatic hydrocarbon group or a C6-10 monovalent aromatic hydrocarbon group, and X 1 each independently represents a monovalent epoxy-substituted organic group or an epoxy-functional siloxy group represented by the following general formula: X 2 -R 14 2SiO(SiR14 20) x SiR 14 2-R 15 - In the formula, R 14 However, each independently represents a C1-6 monovalent aliphatic hydrocarbon group, R 15 However, this represents a C2-6 alkylene group, X 2 However, the term represents a monovalent epoxy-substituted organic group, where "x" represents a number from 0 to 5 and "m" represents a number from 0 to 100, and is used for epoxy-functionalized silicones. (E) Iodonium salt type cationic photoinitiator, (F) A cationic photoinitiator other than component (E) is included.

[0010] In various embodiments, in component (A), R 1 and R 8 Each of these independently represents a vinyl group, and R 2 , R 3 , R 6 , and R 7 Each of these independently represents a C1-6 alkyl group, and R 4 and R 5 Each of these independently represents a C6-12 aryl group, and "n" is an integer from 0 to 40.

[0011] In various embodiments, in component (B), R 9 Each of these independently represents a C1-6 alkyl group, and R 10 Each of these independently represents a C1-6 alkylene group, and R 11 Each of these independently represents a mercapto group.

[0012] In various embodiments, the monovalent epoxy-substituted organic group in component (C) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

[0013] In various embodiments, the monovalent epoxy-substituted organic group in component (D) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

[0014] In various embodiments, component (E) is an iodonium salt type cationic photoinitiator having a structure represented by the following general formula: R 16 2I + X - In the formula, R 16 Each of these independently represents a C1-6 alkyl group, a C6-24 aryl group, or a substituted C6-24 aryl group, X - This represents a non-nucleophilic, non-basic anion.

[0015] In various embodiments, the curable silicone composition further comprises (G) an adhesion promoter, in an amount of about 0.01 to about 5% by mass of the total mass of components (A) to (F).

[0016] The cured product of the present invention is obtained by curing the above-mentioned curable silicone composition. [Effects of the Invention]

[0017] UV-curable silicone-epoxy hybrid materials offer the advantages of both silicone and organic epoxy, making them suitable for the electronic display market. However, preliminary studies have revealed that silicone-epoxy alone is not suitable for applications requiring UV and thermal B-stage dual curing properties. Low-viscosity B-stage materials can offer opportunities in applications requiring multi-stage processability, such as spin-coating die-attach processes in the semiconductor industry. [Brief explanation of the drawing]

[0018] [Figure 1] This graph shows the change over time in the storage modulus of the compositions of Example 1 and Comparative Example 1 after UV irradiation. [Modes for carrying out the invention]

[0019] The terms “comprising” or “comprise” are used herein in their broadest sense, encompassing the ideas of “including,” “include,” “consisting essentially of,” and “consisting of.” The use of “for example,” “eg,” “such as,” and “including” to enumerate examples is not limited to the examples enumerated. Thus, “for example” or “such as” means “for example, but not limited to these” or “such as, but not limited to these,” encompassing other similar or equivalent examples. The term “about” as used herein is useful in reasonably encompassing or describing small variations in numerical values ​​measured by instrumental analysis or as a result of handling a sample. Such small variations may be around ±0 to 25, ±0 to 10, ±0 to 5, or ±0 to 2.5% of the numerical value. Furthermore, the term “about” applies to both numerical values ​​when relating to a range of values. Furthermore, the term “approximately” may apply to numbers even if not explicitly stated. In general, as used herein, ">" means “greater than” or “greater than,” ≥ means “at least” or “greater than or equal to,” < means “below” or “less than,” and ≤ means “at most” or “less than or equal to.”

[0020] As used herein, the terms “epoxy functional” or “epoxy substitution” refer to a functional group in which an epoxy substituent oxygen atom is directly bonded to two adjacent carbon atoms in a carbon chain or ring system. Examples of epoxy-substituted functional groups include, but are not limited to, glycidoxyalkyl groups such as 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl; (3,4-epoxycycloalkyl)alkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl; and epoxyalkyl groups such as 2,3-epoxypropyl, 3,4-epoxybutyl, and 4,5-epoxypentyl.

[0021] <Curing silicone composition> Component (A) is an organopolysiloxane containing an average of two or more alkenyl groups represented by the following general formula:

[0022] [ka]

[0023] In the formula, R 1 and R 8 Each of these independently represents a C2-30 alkenyl group, and R 2 ~R 7 Each of these independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, and "n" is an integer from 0 to 100.

[0024] Examples of C1-30 monovalent aliphatic hydrocarbon groups in component (A) include C1-30 alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl groups, C2-30 alkenyl groups (vinyl, allyl, and hexenyl groups, etc.), and C1-30 halogenated alkyl groups (3-chloropropyl and 3,3,3-trifluoropropyl groups, etc.). Among these, the methyl group is generally preferred.

[0025] Examples of C6-30 monovalent aromatic hydrocarbon groups in component (A) include phenyl, tolyl, xylyl, and naphthyl groups. Among these, the phenyl group is generally preferred.

[0026] In one embodiment of the present invention, R 1 and R 8 Each of these independently represents a vinyl group, and R 2 , R 3 , R 6 , and R 7 Each of these independently represents a C1-6 alkyl group, and R 4 and R 5 Each of these independently represents a C6-12 aryl group, and "n" is an integer from 0 to 40.

[0027] Component (B) is a crosslinking agent having an average of 3 or more mercapto groups represented by the following general formula:

[0028] [ka]

[0029] In the formula, R 9 Each of these independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, R 10 Each of these independently represents a C1-30 divalent aliphatic hydrocarbon group or a C6-30 divalent aromatic hydrocarbon group, R 11 Each of these independently represents a mercapto group or a C1-6 alkyl group, however, R 11 At least three of them must be mercapto groups.

[0030] Examples of C1-30 monovalent aliphatic hydrocarbon groups in component (B) include C1-30 alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl groups, C2-30 alkenyl groups (vinyl, allyl, and hexenyl groups, etc.), and C1-30 halogenated alkyl groups (3-chloropropyl and 3,3,3-trifluoropropyl groups, etc.). Among these, the methyl group is generally preferred.

[0031] Examples of C6-30 monovalent aromatic hydrocarbon groups in component (B) include phenyl, tolyl, xylyl, and naphthyl groups. Among these, the phenyl group is generally preferred.

[0032] Examples of C1-30 divalent aliphatic hydrocarbon groups in component (B) include C1-30 alkylene groups such as methylene, ethylene, propylene, butylene, and hexylene groups, C2-30 alkenylene groups (such as vinylene, propenylene, and hexenylene groups), and C1-30 halogenated alkyl groups (such as 3-chloropropylene and 3,3,3-trifluoropropylene groups). Among these, methylene groups are generally preferred.

[0033] Examples of C6-30 divalent aromatic hydrocarbon groups in component (B) include phenylene, torylene, xylylene, and naphthylene groups. Among these, the phenylene group is generally preferred.

[0034] In one embodiment of the present invention, R 9 Each of these independently represents a C1-6 alkyl group, and R 10 Each of these independently represents a C1-6 alkylene group, and R 11 Each of these independently represents a mercapto group.

[0035] Component (C) is an epoxy-functionalized silicone resin represented by the following average unit formula: (R 12 3SiO 1 / 2 ) a(R 12 2SiO 2 / 2 ) b (R 12 SiO 3 / 2 ) c (SiO 4 / 2 ) d .

[0036] In the formula, R 12 each independently represents a C1-6 monovalent aliphatic hydrocarbon group, a C6-10 monovalent aromatic hydrocarbon group, or a monovalent epoxy-substituted organic group, provided that at least about 15 mol% of all R 12 is a C6-10 monovalent aromatic hydrocarbon group, and "a", "b", "c", and "d" are numbers satisfying the conditions of 0 ≦ a < 0.4, 0 < b < 0.5, 0 < c < d < 0.4, 0.1 ≦ b / c ≦ and a + b + c + d = 1, and about 2 to about 30 mol% of all siloxane units have a monovalent epoxy-substituted organic group.

[0037] Examples of the C1-6 monovalent aliphatic hydrocarbon group in component (C) include C1-6 alkyl groups such as methyl group, ethyl group, propyl group, butyl group, and hexyl group, C2-6 alkenyl groups (such as vinyl group, allyl group, and hexenyl group), and C1-6 halogenated alkyl groups (such as 3-chloropropyl group and 3,3,3-trifluoropropyl group). Among them, the methyl group is generally preferred. A

[0038] Examples of the C6-10 monovalent aromatic hydrocarbon group in component (C) include phenyl group, tolyl group, xylyl group, and naphthyl group. Among them, the phenyl group is generally preferred.

[0039] Examples of the monovalent epoxy-substituted organic group in component (C) include glycidoxyalkyl groups (such as 3-glycidoxypropyl group, 4-glycidoxybutyl group, and 5-glycidoxypentyl group), 3,4-epoxycycloalkylalkyl groups (such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl), and epoxyalkyl groups (such as 2,3-epoxypropyl group, 3,4-epoxybutyl group, and 4,5-epoxypentyl group). Among them, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0040] In component (C), at least about 15 mol%, optionally at least about 20 mol%, or optionally at least about 25 mol% of all R 12 is a C6-10 monovalent aromatic hydrocarbon group. If the content of the monovalent aromatic hydrocarbon group is at or above the above lower limit, the light transmittance of the cured product can be improved, and similarly its mechanical properties can also be improved.

[0041] In the formula, "a", "b", "c", and "d" are mole fractions and numbers that satisfy the conditions of 0 ≦ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≦ d < 0.4, 0.1 ≦ b / c ≦ 0.6, and a + b + c + d = 1, optionally a = 0, 0 < b < 0.5, 0 < c < 1, 0 ≦ d < 0.2, 0.1 < b / c ≦ 0.6, and b + c + d = 1, or optionally a = 0, 0 < b < 0.5, 0 < c < 1, d = 0, 0.1 < b / c ≦ 0.6, and b + c = 1. "a" is 0 ≦ a < 0.4, optionally 0 ≦ a < 0.2, or optionally a = 0, which is because if the (R 12 3SiO 1 / 2 ) siloxane unit is too much, the molecular weight of the epoxy-containing organopolysiloxane resin (C) will decrease, and also (SiO 4 / 2)This is because when siloxane units are introduced, the hardness of the cured product of the epoxy-functional silicone resin (C) may increase significantly, and the cured product may become brittle. For this reason, "d" is 0 ≦ d < 0.4, optionally 0 ≦ d < 0.2, or optionally d = 0. In addition, (R 12 2SiO 2 / 2 ) units and (R 12 SiO 3 / 2 ) units, the molar ratio "b / c" can be about 0.1 or more and about 0.6 or less. In some examples, in the production of the epoxy-functional silicone resin (C), deviating from the above range may result in insoluble by-products, the product becoming more prone to cracking due to a decrease in toughness, or the strength and elasticity of the product being low, making the product more prone to scratching. In some examples, the range of the molar ratio "b / c" is greater than about 0.1 and about 0.6 or less. The epoxy-functional silicone resin (C) contains (R 12 2SiO 2 / 2 ) siloxane units and (R 12 SiO 3 / 2 ) siloxane units, and its molecular structure is, in most cases, a network structure or a three-dimensional structure because the molar ratio of "b / c" is greater than about 0.1 and about 0.6 or less. Therefore, in the epoxy-functional silicone resin (C), (R 12 2SiO 2 / 2 ) siloxane units and (R 12 SiO 3 / 2 ) siloxane units are present, but (R 12 3SiO 1 / 2 ) siloxane units and (SiO 4 / 2 ) siloxane units are optional structural units. That is, an epoxy-functional silicone resin containing the following average unit formula may exist: (R 12 2SiO 2 / 2 ) b (R 12 SiO 3 / 2 ) c (R 12 3SiO 1 / 2 ) a (R 12 2SiO 2 / 2 )b (R 12 SiO 3 / 2 ) c (R 12 2SiO 2 / 2 ) b (R 12 SiO 3 / 2 ) c (SiO 4 / 2 ) d (R 12 3SiO 1 / 2 ) a (R 12 2SiO 2 / 2 ) b (R 12 SiO 3 / 2 ) c (SiO 4 / 2 ) d .

[0042] In component (C), approximately 2 to approximately 30 mol%, optionally approximately 10 mol% to approximately 30 mol%, or optionally approximately 15 mol% to approximately 30 mol% of the total siloxane units in the molecule have epoxy-substituted organic groups. If such siloxane units are present in amounts greater than or equal to the lower limit of the above range, the crosslinking density during curing may be improved. On the other hand, if this amount is below the upper limit of the above range, it may be preferable as it may lead to improved light transmittance and heat resistance of the cured product. In epoxy-functional monovalent hydrocarbon groups, the epoxy groups can be bonded to silicon atoms via alkylene groups, thereby preventing direct bonding of the epoxy groups to the silicon atoms. Epoxy-functional silicone resin (C) can be produced by well-known conventional manufacturing methods.

[0043] There are no particular restrictions on the weight-average molecular weight of the epoxy-functionalized silicone resin (C), but considering the toughness of the cured product and its solubility in organic solvents, in some embodiments the molecular weight is about 10 3 More than and approximately 10 6The following applies: In one embodiment, the epoxy-functionalized silicone resin (C) comprises a combination of two or more such epoxy-functionalized silicone resins having different amounts and types of epoxy-containing organic groups and monovalent hydrocarbon groups, or having different molecular weights.

[0044] Component (D) is an epoxy-functionalized silicone represented by the following general formula: X 1 -R 13 2SiO(SiR 13 20) m SiR 13 2-X 1 .

[0045] In the formula, R 13 Each of these independently represents a C1-6 monovalent aliphatic hydrocarbon group or a C6-10 monovalent aromatic hydrocarbon group. 1 Each of these independently represents a monovalent epoxy-substituted organic group or an epoxy-functionalized siloxy group represented by the following general formula: X 2 -R 14 2SiO(SiR 14 20) x SiR 14 2-R 15 -.

[0046] Examples of C1-6 monovalent aliphatic hydrocarbon groups in component (D) include C1-6 alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl groups, C2-6 alkenyl groups (vinyl, allyl, and hexenyl groups, etc.), and C1-6 halogenated alkyl groups (3-chloropropyl and 3,3,3-trifluoropropyl groups, etc.). Among these, the methyl group is generally preferred.

[0047] Examples of C6-10 monovalent aromatic hydrocarbon groups in component (D) include phenyl, tolyl, xylyl, and naphthyl groups. Among these, the phenyl group is generally preferred.

[0048] X 1Examples of monovalent epoxy-substituted organic groups include glycidoxyalkyl groups (such as 3-glycidoxypropyl group, 4-glycidoxybutyl group, and 5-glycidoxypentyl group), 3,4-epoxycycloalkylalkyl groups (such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl), and epoxyalkyl groups (such as 2,3-epoxypropyl group, 3,4-epoxybutyl group, and 4,5-epoxypentyl group). Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0049] In the general formula above, each R 14 These are the same or different C1-6 monovalent aliphatic hydrocarbon groups. 14 Examples of C1-6 monovalent aliphatic hydrocarbon groups include C1-6 alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl groups, C2-6 alkenyl groups (vinyl, allyl, and hexenyl groups, etc.), and C1-6 halogenated alkyl groups (3-chloropropyl and 3,3,3-trifluoropropyl groups, etc.). Among these, the methyl group is generally preferred.

[0050] In the general formula above, R 15 This is a C2-6 alkylene group. 15 Examples of C2-6 alkylene groups include ethylene, methylethylene, propylene, butylene, and hexylene. Among these, the ethylene group is generally preferred.

[0051] In the above general formula, X 2 X is a monovalent epoxy-substituted organic group. 2Examples of monovalent epoxy-substituted organic groups include glycidoxyalkyl groups (such as 3-glycidoxypropyl group, 4-glycidoxybutyl group, and 5-glycidoxypentyl group), 3,4-epoxycycloalkylalkyl groups (such as 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl, and 3-(2,3-epoxycyclopentyl)propyl), and epoxyalkyl groups (such as 2,3-epoxypropyl group, 3,4-epoxybutyl group, and 4,5-epoxypentyl group). Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0052] In the general formula above, "x" is a number that is approximately 0 to approximately 5, arbitrarily approximately 0 to approximately 2, or arbitrarily selected to be approximately 0.

[0053] In the general formula above, "m" is a number between approximately 0 and 100, optionally between approximately 0 and 20, or optionally between approximately 0 and 10. When "m" is below the upper limit of the above range, the mechanical strength of the cured product can be improved.

[0054] The state of component (D) at 25°C is not limited, but is generally liquid. The viscosity of component (D) at 25°C is not limited, but is generally in the range of approximately 5 to approximately 100 mPa·s. In this specification, viscosity is the value measured at 23±2°C using a B-type viscometer in accordance with ASTM D1084.

[0055] Component (E) is a cationic photoinitiator used as a photoinitiator for epoxy-functionalized silicones, and is an iodonium salt type cationic photoinitiator.

[0056] Iodonium salt-type cationic photoinitiators are not particularly limited, but one example may be a compound having a structure represented by the following general formula: R 16 2I + X - .

[0057] In the formula, R 16 Each of these independently represents a C1-6 alkyl group, a C6-24 aryl group, or a substituted C6-24 aryl group, X - This represents a non-nucleophilic, non-basic anion.

[0058] In the formula, R 16 X can be a methyl group, ethyl group, propyl group, butyl group, and other C1-6 alkyl groups; phenyl, naphthyl, biphenyl, tolyl, propylphenyl, decylphenyl, dodecylphenyl, and other C6-24 aryl groups; or an alkyl group, aryl group, alkoxy group, mercapto atom, oxygen atom, or other heteroatom-substituted aryl group, where X - SbF6 - AsF6 - PF6 - BF4 - , B(C6F5)4 - HSO4 - ClO4 - CF3SO3 - It can represent nonafluorobutanesulfonate, tris(pentafluoroethyl)trifluorophosphate, tris(heptafluoropropyl)trifluorophosphate, tris(nonafluoroisobutyl)trifluorophosphate, bis(nonafluorobutylisobutyl)tetrafluorophosphate, and other non-nucleophilic nonbasic anions.

[0059] In the formula, each R 16 Preferably, the cation is a C6-24 aryl group, an alkyl group, or an alkoxy-substituted aryl group. Specific examples of the cation moiety of diaryliodonium salts include diphenyliodonium, 4-isopropyl-4'-methyldiphenyliodonium, 4-methyl-4'-methyl-propyldiphenyliodonium, bis(4-tert-butylphenyl)iodonium, and 4-methoxyphenylphenyliodonium.

[0060] Specific examples of iodonium salt-type cationic photoinitiators include compounds represented by the following formula:

[0061] [ka]

[0062] In the above formula, "Me", "i-Pr", and "t-Bu" represent a methyl group, an isopropyl group, and a tert-butyl group, respectively. - The same applies as above.

[0063] Specific trade names for iodonium salt-type cationic photoinitiators include TR-PAG-30101, 30201, 30408, 30401s, and 31102 (manufactured by TRONYL).

[0064] Component (F) is a cationic photoinitiator other than component (E) described above, which is a photoinitiator for UV thiol-ene curing. This component enables the composition of the present invention to enter the B-stage of UV by curing the composition, i.e., the thiol-ene in components (A) and (B).

[0065] In formulations containing both a photoacid generator (PAG) and a heat-activated generator (HAG) to achieve UV B-stage and thermal double curing, it was observed that UV irradiation did not result in a B-stage where the elastic modulus did not change over time until exposed to thermal curing conditions. Varying the UV irradiation time did not affect the stabilization of the storage modulus.

[0066] The composition of the present invention is required to be UV and thermosetting, have a stable elastic modulus over time after UV curing (B-stage possible), and exhibit an increased elastic modulus in the C-stage (thermosetting) when the B-stage material is exposed to heat. It has been found that combining a curing system orthogonal to silicone epoxy yields B-stage properties that cannot be obtained with Si-Ep alone.

[0067] Examples of component (F) include alpha-hydroxyketone and derivatives thereof (1-hydroxycyclohexylphenyl-ketone; 2-hydrochlor-2-methyl-1-phenyl-1-propanone; 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone); phenylglyoxylate and derivatives thereof (methylbenzoylformate; oxyphenyl-acetate 2-[2-oxo-2-oxyphenyl-acetate 2-[2-oxo-2-phenylacetoxy-ethoxy]-ethyl ester and oxyphenyl-acetate 2-[2-hydroxyethoxy]-ethyl ester); benzyldimethyl ketal and derivatives thereof (alpha,alpha-dimethoxy-alpha-phenylacetophenone). Alpha-amino ketones and derivatives thereof (2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone; 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone / IRGACURE 369 (30% by weight) + IRGACURE 651 (70% by weight); monoacylphosphine (MAPO) and derivatives thereof (diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide.MAPO / alpha-hydroxy ketones and derivatives thereof (DAROCUR TPO (50% by weight) + DAROCUR 1173 (50% by weight)); bisacylphosphine (BAPO) and derivatives thereof (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide); BAPO dispersion (IRGACURE dispersed in water) Examples include 819 (45% activity); BAPO / alpha-hydroxyketone (IRGACURE 819 (20% by weight) + DAROCUR 1173 (80% by weight); titanium (bis(ethanol-5-2,4-cyclopentadiene-1-yl), bis[2,6-difluoro-3-(1H-pyrrole-1-yl),phenyl]titanium)).

[0068] In one embodiment of the present invention, 2-hydroxy-2-methyl-1-phenyl-1-propanone may be used as component (F).

[0069] This composition contains the above components (A) to (F), but may also contain (G) an adhesion promoter and / or a photosensitizer and / or an alcohol to impart better mechanical strength to the cured product of this composition.

[0070] Component (G) is an adhesion promoter. Examples of adhesion promoters include epoxy-functional alkoxysilanes (e.g., 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldiethoxysilane, and combinations thereof); unsaturated alkoxysilanes (e.g., vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxy Examples include propyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, and combinations thereof); epoxy-functionalized siloxanes having silicon-bonded alkoxy groups (e.g., reaction products of hydroxy-terminated polyorganosiloxanes and epoxy-functionalized alkoxysilanes (e.g., one of the above), or physical blends of hydroxy-terminated polyorganosiloxanes and epoxy-functionalized alkoxysilanes). Adhesion promoters may include combinations of epoxy-functionalized alkoxysilanes and epoxy-functionalized siloxanes. For example, adhesion promoters are exemplified by a mixture of 3-glycidoxypropyltrimethoxysilane and a reaction product of hydroxy-terminated methylvinylsiloxane and 3-glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane and hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane and hydroxy-terminated methylvinyl / dimethylsiloxane copolymer.

[0071] The content of component (G) is not limited, but is generally about 0.01 to 5% by mass of the total mass of components (A) to (F), or optionally about 0.1 to 2% by mass. If the content of component (G) is above the lower limit of the above range, the adhesion of the cured product may be improved. On the other hand, if it is below the upper limit of the above range, the mechanical properties of the cured product may be improved.

[0072] Examples of photosensitizers include isopropyl-9H-thioxanthene-9-one, anthrone, 1-hydroxycyclohexyl-phenyl ketone, 2,4-diethyl-9H-thioxanthene-9-one, 2-isopropylthioxanthene, 2-hydroxy-2-methylphenylpropane-1-one, 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT), and pentaerythritol tetrakis[3-(3,5-di-tert-br]. [3,5-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[{3,5-bis(1,1-di-tert-butyl-4-hydroxyphenyl)methyl}phosphonate, 3 Examples include 3',3'',5,5',5''-hexane-tert-butyl-4-a,a',a''-(mesitylene-2,4,6-tolyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], and hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0073] Examples of alcohols include monohydric alcohols (e.g., ethyl alcohol, isopropyl alcohol, isobutyl alcohol, 1-decanol, 1-dodecanol, 1-octanol, oleyl alcohol, 1-hexadecanol, and stearyl alcohol); and polyhydric alcohols (e.g., ethylene glycol, diethylene glycol, propylene glycol, 1,10-decanediol, glycerol, and pentaerythritol).

[0074] This composition can be cured by irradiation with UV light (i.e., ultraviolet ("UV") light). For example, low-pressure, high-pressure, or ultra-high-pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, or electrodeless lamps are useful as UV lamps. The irradiation dose is approximately 5 to 6,000 mJ / cm². 2 Within this range, or optionally, approximately 10 to approximately 4,000 mJ / cm² 2 It is within the range.

[0075] <Cured product> This composition forms a cured product when cured by irradiation with UV light. The cured product according to the present invention has a hardness in the range of at least 20 to 95, typically at least 30 to 80, and more typically at least 30 to 70, when measured using the Shore D hardness scale as defined in ASTM D2240. The reason for this is as follows: if the hardness of the cured product is below the lower limit of the range described, the strength of the cured product may be insufficient, while if it exceeds the upper limit of the range described, the flexibility of the cured product tends to be insufficient.

[0076] To exhibit satisfactory flexibility, the cured product may have an elongation of at least 10%, as specified in ASTM D412. This is because below this range, the flexibility of the cured product becomes insufficient.

[0077] The cured product of the present invention demonstrates highly reliable B-stage characteristics and enables adjustment of adhesiveness, thus being useful as a member or component for semiconductor packaging. The uncured product of the present invention must demonstrate B-stage characteristics during an initial photocuring process, such as visible light, infrared rays, ultraviolet rays, far ultraviolet rays, X-rays, lasers, etc., in order to facilitate the die preparation process and achieve a bond line thickness of less than 5 micrometers. Therefore, it is useful as a member or component of a liquid-type adhesive that can be spin-coated onto a silicon wafer. The B-stage cured product of the present invention is useful as a member or component that must demonstrate adhesive characteristics enabling a die lamination process.

Examples

[0078] Here, the curable silicone composition and cured product of the present invention will be described in detail using examples and comparative examples. It should be noted that in the formula, "Me", "Pr", "Vi", "Ph", "Gly", and "Ep" represent a methyl group, a propyl group, a vinyl group, a phenyl group, a 3-glycidoxypropyl group, and a 2-(3,4-epoxycyclohexyl)ethyl group, respectively. The structure of the silicone resin used in the examples was determined by performing 1 H NMR and 29 Si NMR measurements. The weight average molecular weight of the silicone resin was calculated using GPC based on comparison with a polystyrene standard. The specifications for UV curing, high-temperature curing, hardness, viscosity, elastic modulus, and B-stage characteristics are as follows.

[0079] <UV Curing> All samples were cured by an LED UV (Firejet FJ800) device at a UVA dose of 365 nm and an energy of 5,000 mJ / cm 2 .

[0080] <High-Temperature Curing Property> After UV irradiation, all samples were immediately cured in an oven set at 150°C for 60 minutes.

[0081] <Hardness> Hardness was measured using a durometer (Shore D). The cured samples were prepared with a thickness exceeding 6 mm, and the surface of the cured samples was made as flat as possible to reduce variations. The hardness at at least three points on the flat surface was measured, and the average hardness value was used.

[0082] <Viscosity> The viscosity of all samples was measured using a Brookfield cone plate viscometer (HADV-IIIU) equipped with a cone spindle CP-52. The measurement temperature was 25 ± 0.2 °C, and the samples were measured at a speed where the torque was 50 - 70%.

[0083] <Elastic modulus> The elastic modulus of all samples was measured using an Anton Parr Modular Compact Rheometer (MCR 502) with a torsion rectangular setting. The measurement vibration was 0.01% at 1 Hz with a vertical force of 0.5 N. The temperature range was -60 to 250 °C, and the heating rate was 10 °C / min. The elastic modulus was measured in the presence of UV irradiation and after stopping the UV irradiation.

[0084] <B-stage characteristics> The measurement of B-stage characteristics was achieved by applying a liquid sample onto an Anton Parr Modular Compact Rheometer (MCR 502) with a 7 mm spindle equipped with a UV irradiation accessory. The measurement vibration was 0.1% at 1 Hz with a vertical force of 0.5 N. The UV irradiation accessory (OmniCure Series 2000) was used to irradiate the sample during the elastic modulus measurement to monitor the change in elastic modulus during UV curing. The measurement of the B-stage holding characteristics was performed by preparing a UV-cured torsion rectangular sample (5,000 mJ, 365 nm UV LED, 2 mm thickness, 10 × 45 mm) and measuring the change in elastic modulus over time.

[0085] <Example 1> An organopolysiloxane composition capable of UV and thermal B-staging was prepared by blending 22.50 parts by mass of siloxane resin (C), 50.00 parts by mass of epoxy-functionalized crosslinking agent (D), 20.00 parts by mass of siloxane polymer (A), 1.50 parts by mass of SH crosslinking agent (B), 1.00 part by mass of photoinitiator (F), and 5.00 parts by mass of HAG (E). The mixture was mixed under vacuum at 1,500 rpm for 2 minutes. The well-mixed sample was packed into a 30 mL syringe and sealed under vacuum. Intrinsic properties (viscosity, modulus of elasticity, etc.) were measured, and then the sample was stored at a negative temperature (-5°C).

[0086] <Examples 2-5> Samples were prepared in the same manner as in Example 1, except that the formulation amounts were varied as shown in Table 3 below. Examples 2 to 5 illustrate the capability of this technique to control the desired modulus of elasticity in the B-stage by varying the SH / Vi and thiolene / Si-Ep ratios.

[0087] <Comparative Example 1> A UV and thermosetting organopolysiloxane composition was prepared by blending 20.00 parts by mass of siloxane resin (C), 70.00 parts by mass of epoxy-functionalized crosslinking agent (D), 5.00 parts by mass of PAG, and 5.00 parts by mass of HAG solution (HAG:epoxy-functionalized crosslinking agent (C) = 1:9) (E). The mixture was mixed under vacuum at 1,500 rpm for 2 minutes. The well-mixed sample was packed into a 30 mL syringe and sealed under vacuum. Intrinsic properties (viscosity, modulus of elasticity, etc.) were measured, and the sample was then stored at a negative temperature (-5°C).

[0088] Curable silicone compositions for the examples and comparative examples were prepared using the components listed in Table 1.

[0089] [Table 1]

[0090] [Table 2]

[0091] [Table 3]

[0092] [Table 4]

[0093] [Table 5]

[0094] The B-stageable silicone compositions of Examples 1-5 yielded low viscosity materials in the range of 154-185 cP. After discontinuing UV irradiation, the change in elastic modulus over time in Example 1 was stable, as shown in Figure 1, illustrating the B-stage properties that enable processability. The increase in elastic modulus after reaching the saturation modulus, as shown in Figure 1, being less than 10% demonstrated the B-stage properties. Hardness measurements showed the flexibility of the B-stage material (Shore 0.0, 62-91), which hardened significantly after thermal curing (Shore D, 70-77). The measured elastic modulus also correlated with hardness, with the B-stage elastic modulus (1.16-17.3 MPa) increasing after thermal curing (189-443 MPa). Such large differences in hardness and elastic modulus between the B-stage and final cured stages also meet the success criteria for B-stageable materials.

[0095] In contrast, Comparative Example 1 aimed to obtain a B-stageable Si-Ep material by adding PAG and HAG to initiate UV curing, followed by a stepwise thermal curing process. However, upon UV irradiation, the elastic modulus increased continuously over time, as shown in Figure 1. This demonstrates that Si-Ep alone cannot achieve B-stage properties due to uncontrollable epoxy curing. Measurements of hardness and elastic modulus after UV irradiation and thermal curing showed only slight differences, further illustrating the failure of B-stage capability. [Industrial applicability]

[0096] The curable silicone composition of the present invention can be cured by irradiation with UV light. Therefore, this composition is useful as a various adhesive, encapsulant, coating agent, etc. for electrical / electronic components.

Claims

1. A curable silicone composition, (A) An organopolysiloxane containing an average of two or more alkenyl groups represented by the following general formula, 【Chemistry 1】 In the formula, R １ and R ８ However, each independently represents a C2-30 alkenyl group, R ２ ~R ７ However, each independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, and "n" is an integer from 0 to 100, and is an organopolysiloxane. (B) A crosslinking agent having an average of three or more mercapto groups represented by the following general formula, 【Chemistry 2】 In the formula, R ９ However, each independently represents a C1-30 monovalent aliphatic hydrocarbon group or a C6-30 monovalent aromatic hydrocarbon group, R １０ However, each independently represents a C1-30 divalent aliphatic hydrocarbon group or a C6-30 divalent aromatic hydrocarbon group, R １１ However, each independently represents a mercapto group or a C1-6 alkyl group, provided that the R １１ A crosslinking agent, provided that at least three of them are mercapto groups, (C) An epoxy-functional silicone resin represented by the following average unit formula, (R １２ ３ SiO １／２ ) ａ (R １２ ２ SiO ２／２ ) ｂ (R １２ SiO ３／２ ) ｃ (SiO ４／２ ) ｄ In the formula, R １２ However, each independently represents a C1-6 monovalent aliphatic hydrocarbon group, a C6-10 monovalent aromatic hydrocarbon group, or a monovalent epoxy-substituted organic group, provided that all R １２ The epoxy-functionalized silicone resin is characterized in that at least about 15 mol% of it is a C6-10 monovalent aromatic hydrocarbon group, and "a", "b", "c", and "d" are numbers that satisfy the conditions 0 ≤ a < 0.4, 0 < b < 0.5, 0 < c < 1, 0 ≤ d < 0.4, 0.1 ≤ b / c ≤ 0.6, and a + b + c + d = 1, and about 2 to about 30 mol% of the total siloxane units are the monovalent epoxy-substituted organic groups. (D) An epoxy-functionalized silicone represented by the following general formula, X １ -R １３ ２ SiO(SiR １３ ２ O) ｍ SiR １３ ２ -X １ In the formula, R １３ However, each independently represents a C1-6 monovalent aliphatic hydrocarbon group or a C6-10 monovalent aromatic hydrocarbon group, X １ However, each independently represents a monovalent epoxy-substituted organic group or an epoxy-functionalized siloxy group represented by the following general formula: X ２ -R １４ ２ SiO(SiR １４ ２ O) ｘ SiR １４ ２ -R １５ - In the formula, R １４ However, each independently represents a C1-6 monovalent aliphatic hydrocarbon group, R １５ However, this represents a C2-6 alkylene group, X ２ However, the term represents a monovalent epoxy-substituted organic group, where "x" represents a number from 0 to 5, and "m" represents a number from 0 to 100, and is used for epoxy-functionalized silicones. (E) Iodonium salt type cationic photoinitiator, A curable silicone composition comprising (F) a cationic photoinitiator other than component (E).

2. In component (A), R １ and R ８ However, each independently represents a vinyl group, R ２ , R ３ , R ６ , and R ７ However, each independently represents a C1-6 alkyl group, R ４ and R ５ The curable silicone composition according to claim 1, wherein each independently represents a C6-C12 aryl group, and "n" is an integer from 0 to 40.

3. In component (B), R ９ However, each independently represents a C1-6 alkyl group, R １０ However, each independently represents a C1-6 alkylene group, R １１ The curable silicone composition according to claim 1, wherein each independently represents a mercapto group.

4. The curable silicone composition according to claim 1, wherein the monovalent epoxy-substituted organic group in component (C) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

5. The curable silicone composition according to claim 1, wherein the monovalent epoxy-substituted organic group in component (D) is a group selected from glycidoxyalkyl groups, 3,4-epoxycyclohexylalkyl groups, and epoxyalkyl groups.

6. Component (E) is given by the following general formula: R １６ ２ I ＋ X － It is an iodonium salt type cationic photoinitiator having a structure represented by, In the formula, R １６ However, each independently represents a C1-6 alkyl group, a C6-24 aryl group, or a substituted C6-24 aryl group, X － The curable silicone composition according to claim 1, wherein the anion is a non-nucleophilic non-basic anion.

7. (G) The curable silicone composition according to any one of claims 1 to 6, further comprising an adhesion promoter in an amount of about 0.01 to about 5% by mass of the total mass of components (A) to (F).

8. A cured product obtained by curing the curable silicone composition according to any one of claims 1 to 8.

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