Curable silicone composition and cured product thereof

Abstract

A curable silicone composition is provided. The composition comprises (A) an epoxy-functional silicone resin having a monovalent aromatic hydrocarbon group, (B) an epoxy-functional silicone having a monovalent aromatic hydrocarbon group, and (C) a cationic photoinitiator. Optionally, the composition further comprises (D) an epoxy-functional silicone not having a monovalent aromatic hydrocarbon group. The composition exhibits excellent curability upon exposure to UV radiation and further heating, generally forming a cured product with excellent transparency and mechanical properties.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the priority and all advantages of U.S. Provisional Patent Application No. 62 / 950,081, filed on December 18, 2019, the content of which is incorporated herein by reference.

[0002] (Field of the Invention) The present invention relates to curable silicone compositions and cured products thereof.

Background Art

[0003] Epoxy - functional silicone is used in curable silicone compositions that can be cured by irradiating ultraviolet light (“UV”). For example, Patent Document 1 discloses a curable silicone composition, which is an epoxy - functional silicone resin represented by the average unit formula (R3SiO iv , iii , ii , v , i , 6~10 , 1~6 , 4 / 2 , 3 / 2 , 2 / 2 , 1 / 2 , 1~8 , 6~10 ) i (R2SiO 2 / 2 ) ii (RSiO 3 / 2 ) iii (SiO 4 / 2 ) iv wherein each R is an organic group independently selected from a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, and a monovalent epoxy - substituted organic group, 0 ≦ i < 0.4, 0 < ii < 0.5, 0 < iii < 1, 0 ≦ iv < 0.4, 0.1 ≦ ii / iii ≦ 0.3, i + ii + iii + iv = 1, this resin has a number - average molecular weight of at least about 2,000, and at least about 15 mol% of the organic groups are monovalent aromatic hydrocarbon groups, and about 2 to about 50 mol% of the siloxane units have epoxy - substituted organic groups, an epoxy - functional silicone resin; and an epoxy - functional silicone oligomer represented by the general formula R’’R’2SiO(R’2SiO) v SiR’2R’’, wherein each R’ is C 1~8 ​​​​​​wherein R is an alkyl group, each R″ is an epoxy-substituted organic group, and “v” is 0 or a positive integer; and a cationic photoinitiator, wherein the composition can be cured by exposure to UV light.

[0004] However, such curable silicone compositions have problems in that the compositions do not cure sufficiently, or the transparency and mechanical properties of the cured product are insufficient.

[0005] Therefore, it is desirable to develop a curable silicone composition that has excellent curability upon UV irradiation and further heating to form a cured product with good transparency and mechanical properties. [Prior art documents] [Patent documents]

[0006] Patent Document 1: U.S. Patent Application Publication No. 2014 / 154626(A1) Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a curable silicone composition that has excellent curing properties upon UV irradiation and further heating to form a cured product with good transparency and mechanical properties. Another object of the present invention is to provide a cured product with excellent adhesion / bonding strength, transparency, and mechanical properties. [Means for solving the problem]

[0008] The curable silicone composition of the present invention comprises: (A) an epoxy-functional silicone resin represented by the average unit formula: (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO3 / 2 ) c (SiO 4 / 2 ) d In the formula, each R 1 is an organic group, the same or different, selected from a monovalent aliphatic hydrocarbon group, a monovalent aromatic hydrocarbon group, and a monovalent epoxy-substituted organic group, provided that at least about 15 mol% of all R 1~6 is a monovalent aromatic hydrocarbon group, and "a", "b", "c", and "d" 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, and about 2 to about 30 mol% of all siloxane units have a monovalent epoxy-substituted organic group, an epoxy-functional silicone resin, and 6~10 (B) An epoxy-functional silicone represented by the following general formula: X 1 -R 2 2SiO(SiR 2 2O) m SiR 2 2-X 1 In the formula, each R 2 is an organic group, the same or different, selected from a monovalent aliphatic hydrocarbon group and a monovalent aromatic hydrocarbon group, provided that at least about 10 mol% of all R 1~6 is a monovalent aromatic hydrocarbon group, and each X 6~10 is a group, the same or different, selected from a monovalent epoxy-substituted organic group and an epoxy-functional siloxy group represented by the following general formula: X 2 -R 3 2SiO(SiR 3 2O) x SiR 3 2-R 4 - In the formula, each R 3 is the same or different C 1~6 monovalent aliphatic hydrocarbon group, R 4 is a C 2~6 alkylene group, X​​​​​​​​​​​2 is a monovalent epoxy-substituted organic group, and "x" is a number from about 0 to about 5; "m" is a number from about 5 to about 100, and an epoxy-functional silicone in an amount of about 5% to about 40% by weight of the total weight of components (A), (B), and (C); (C) a cationic photoinitiator in an amount of about 0.2% to about 2% by weight of the total weight of components (A), (B), and (C).

[0009] In various embodiments, the monovalent epoxy-substituted organic group in component (A) is a group selected from a glycidoxyalkyl group, a 3,4-epoxycyclohexylalkyl group, and an epoxyalkyl group.

[0010] In various embodiments, the monovalent epoxy-substituted organic group in component (B) is a group selected from a glycidoxyalkyl group, a 3,4-epoxycyclohexylalkyl group, and an epoxyalkyl group.

[0011] In various embodiments, the curable silicone composition comprises (D) an epoxy-functional silicone having the general formula: X 1 -R 3 2SiO(SiR 3 2O) n SiR 3 2-X 1 In the formula, each R 3 are the same or different C 1~6 is a monovalent aliphatic hydrocarbon group, and each X 1 are the same or different groups selected from monovalent epoxy-substituted organic groups and epoxy-functional siloxy groups represented by the general formula: X 2 -R 3 2SiO(SiR 3 2O) x SiR 3 2-R 4 - In the formula, each R 3 are the same or different C 1~6 is a monovalent aliphatic hydrocarbon group, R4 is C 2~6 is an alkylene group, and X 2 is a monovalent epoxy-substituted organic group, and "x" is a number from about 0 to about 5; "n" is a number from about 0 to about 10, and further comprises an epoxy-functional silicone in an amount of from about 0.1% to about 10% by weight of the total weight of components (A), (B), (C), and (D).

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

[0013] In various embodiments, the curable silicone composition further comprises (E) an adhesion promoter in an amount of about 0.01 to about 5 weight percent of the total weight of components (A), (B), (C), and (E).

[0014] In various embodiments, the curable silicone composition further comprises (F) a photosensitizer in an amount of about 0.001 to about 0.1 weight percent of the total weight of components (A), (B), (C), and (F).

[0015] In various embodiments, the curable silicone composition further comprises (G) an alcohol in an amount of about 0.01 to about 10 weight percent of the total weight of components (A), (B), (C), and (G).

[0016] In various embodiments, the curable silicone composition further comprises (H) an inorganic filler in an amount of about 1 to about 95 weight percent of the total weight of components (A), (B), (C), and (H).

[0017] The cured product of the present invention can be obtained by curing the above-described curable silicone composition. Effect of the invention

[0018] The curable silicone composition of the present invention exhibits excellent curability upon UV irradiation and subsequent heating, forming a cured product with excellent transparency and mechanical properties. At the same time, the cured product of the present invention also exhibits excellent adhesiveness / adhesion strength, transparency, and mechanical properties. DETAILED DESCRIPTION OF THE INVENTION

[0019] The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the ideas of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "e.g.," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and encompasses other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or account for slight variations in a numerical value as determined by instrumental analysis or as a result of sample handling. Such slight variations may be on the order of ±0-25%, ±0-10%, ±0-5%, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may apply to numerical values ​​even if not expressly stated.

[0020] Generally, as used herein, a hyphen "-" or a wavy line "~" in a range of values ​​means "to" or "through," ">" means "above" 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." Each of the foregoing patent applications, patents, and / or patent publications is expressly incorporated herein by reference in its entirety on an individual basis in one or more non-limiting embodiments.

[0021] It should be understood that the scope of the appended claims is not limited to the language set forth in the detailed description and to the specific compounds, compositions, or methods, which may vary among specific embodiments within the scope of the appended claims. With respect to any Markush group relied upon herein to describe particular features or aspects of various embodiments, it should be understood that different, extraordinary, and / or unexpected results may be obtained from each element of the respective Markush group independently of all other Markush elements. Each element of a Markush group may be relied upon individually and / or in combination to provide appropriate support for specific embodiments within the scope of the appended claims.

[0022] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and to be understood to describe and contemplate all ranges, including integer and / or fractional values ​​therein, even if such values ​​are not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further delineated into related halves, thirds, fourths, fifths, etc. As merely an example, a range of "0.1 to 0.9" may be further delineated into a lower third, i.e., 0.1 to 0.3, a middle third, i.e., 0.4 to 0.6, and an upper third, i.e., 0.7 to 0.9, which are individually and inclusively within the scope of the appended claims and may be relied upon and provide sufficient support for specific embodiments within the scope of the appended claims, individually and / or inclusively. Furthermore, with respect to terms defining or modifying a range, such as "at least," "greater than," "less than," "less than or equal to," etc., such terms should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" inherently includes subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., and each subrange may be relied upon and fully supported, individually and / or inclusively, for specific embodiments within the appended claims. Finally, individual numbers within the disclosed ranges may be relied upon and fully supported for specific embodiments within the appended claims. For example, the range "1 to 9" includes various individual integers, such as 3, as well as individual numbers including decimal points (or fractions), such as 4.1, which may be relied upon and fully supported for specific embodiments within the appended claims.

[0023] As used herein, the term "epoxy-functional" or "epoxy-substituted" refers to a functional group in which the oxygen atoms of the epoxy substituent are 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.

[0024] Curable silicone composition Component (A) is an epoxy-functional silicone resin represented by the following average siloxane unit formula: (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d .

[0025] In the formula, each R 1 is C 1~6 Monovalent aliphatic hydrocarbon radical, C 6~10 They are the same or different organic groups selected from monovalent aromatic hydrocarbon groups and monovalent epoxy-substituted organic groups.

[0026] C in component (A) 1~6 Examples of monovalent aliphatic hydrocarbon groups include C 11 groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0027] C in component (A) 6~10 Examples of monovalent aromatic hydrocarbon groups include phenyl, tolyl, xylyl, and naphthyl groups, with phenyl being generally preferred.

[0028] Examples of the monovalent epoxy-substituted organic group in component (A) include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 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, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0029] In component (A), all R 1 at least about 15 mol %, optionally at least about 20 mol %, or optionally at least about 25 mol % of 6~10 When the content of the monovalent aromatic hydrocarbon group is equal to or greater than the above lower limit, the light transmittance of the cured product can be improved, and the mechanical properties thereof can also be improved.

[0030] 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, or 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, but it is because when there are too many (R 1 3SiO 1 / 2 ) siloxane units, the molecular weight of the epoxy-containing organopolysiloxane resin (A) decreases, and also when (SiO 4 / 2 ) siloxane units are introduced, the hardness of the cured product of the epoxy-functional silicone resin (A) increases 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, the molar ratio "b / c" of the (R 1 2SiO 2 / 2 ) unit and the (R 1 SiO 3 / 2 ) unit 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 (A), if it is out of this range, insoluble by-products may occur, the toughness decreases and the product is likely to crack, or the strength and elasticity of the product may be low and it is likely to be scratched. In some examples, the range of the molar ratio "b / c" is greater than about 0.1 and less than or equal to about 0.6. The epoxy-functional silicone resin (A) contains (R 1 2SiO 2 / 2 ) siloxane units and (R 1 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 less than or equal to about 0.6. Therefore, in the epoxy-functional silicone resin (A), (R 1 2SiO 2 / 2 ) siloxane units and (R 1 SiO 3 / 2) siloxane units are present, but (R 1 3SiO 1 / 2 ) siloxane units and (SiO 4 / 2 The siloxane unit is an optional constituent unit. That is, there may be an epoxy-functional silicone resin comprising the average unit formula: (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d

[0031] In component (A), about 2 to about 30 mol%, optionally about 10 mol% to about 30 mol%, or optionally about 15 mol% to about 30 mol% of the siloxane units in the molecule contain epoxy-substituted organic groups. The presence of such siloxane units at or above the lower limit of the above range can improve crosslink density during curing. On the other hand, an amount below the upper limit of the above range can be advantageous because it can improve the light transmittance and heat resistance of the cured product. In the epoxy-functional monovalent hydrocarbon group, the epoxy group can be bonded to the silicon atom via an alkylene group, thereby avoiding direct bonding to the silicon atom. The epoxy-functional silicone resin (A) can be produced by well-known conventional manufacturing methods.

[0032] There is no particular limitation on the weight average molecular weight of the epoxy-functional silicone resin (A). However, in consideration of the toughness of the cured product and its solubility in organic solvents, in some embodiments, the molecular weight is about 10 3 More than or equal to approximately 10 6 In one embodiment, the epoxy-functional silicone resin (A) comprises a combination of two or more such epoxy-functional silicone resins having different amounts and types of epoxy-containing organic groups and monovalent hydrocarbon groups, or having different molecular weights.

[0033] Component (B) is an epoxy-functional silicone having the following general formula: X 1 -R 2 2SiO(SiR 2 2O) m SiR 2 2-X 1 .

[0034] In the formula, each R 2 is C 1~6 Monovalent aliphatic hydrocarbon groups and C 6~10 are the same or different organic groups selected from monovalent aromatic hydrocarbon groups.

[0035] C in component (B) 1~6Examples of monovalent aliphatic hydrocarbon groups include C 11 groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0036] C in component (B) 6~10 Examples of monovalent aromatic hydrocarbon groups include phenyl, tolyl, xylyl, and naphthyl groups, with phenyl being generally preferred.

[0037] In component (B), all R 2 at least about 10 mol %, optionally at least about 20 mol %, optionally at least about 30 mol %, or optionally at least about 40 mol % of 6~10 When the content of the monovalent aromatic hydrocarbon group is equal to or greater than the above lower limit, the light transmittance of the cured product can be improved, and the mechanical properties of the cured product can also be improved.

[0038] In the formula, each 1 are the same or different groups selected from monovalent epoxy-substituted organic groups and epoxy-functional siloxy groups represented by the general formula: X 2 -R 3 2SiO(SiR 3 2O) x SiR 3 2-R 4 -.

[0039] X 1Examples of the monovalent epoxy-substituted organic group include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 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, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0040] In the above general formula, each R 3 are the same or different C 1~6 R is a monovalent aliphatic hydrocarbon group. 3 C 1~6 Examples of monovalent aliphatic hydrocarbon groups include C 11 groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0041] In the above general formula, R 4 is C 2~6 is an alkylene group. 4 C 2~6 Examples of alkylene groups include ethylene, methylethylene, propylene, butylene, and hexylene groups, with the ethylene group being generally preferred.

[0042] In the above general formula, X 2 is a monovalent epoxy-substituted organic group. 2Examples of the monovalent epoxy-substituted organic group include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 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, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0043] In the above general formula, "x" is a number from about 0 to about 5, optionally from about 0 to about 2, or optionally about 0.

[0044] In the above general formula, "m" is a number of about 5 to about 100, optionally about 5 to about 50, or optionally about 10 to about 50. When "m" is equal to or greater than the lower limit of the above range, the impact strength of the cured product can be improved, and the reliability properties of the cured product can also be improved.

[0045] The state of component (B) at 25°C is not limited, but it is generally a liquid. The viscosity of component (B) at 25°C is not limited, but it is generally within the range of about 100 to about 1,000,000 mPa·s. In this specification, viscosity is a value measured at 23±2°C using a Brookfield viscometer in accordance with ASTM D 1084.

[0046] The content of component (B) is about 5% to about 40% by mass, optionally about 10% to about 40% by mass, optionally about 10% to about 35% by mass, or optionally about 10% to about 30% by mass of the total mass of components (A), (B), and (C). If the content of component (B) is at or above the lower limit of the above range, the flexibility and impact strength of the cured product can be improved. On the other hand, if the content is at or below the upper limit of the above range, the toughness and tensile strength of the cured product can be improved.

[0047] Component (C) is a cationic photoinitiator used as a photoinitiator for epoxy-functional silicones. Any cationic photoinitiator known to those skilled in the art can be used, such as sulfonium salts, iodonium salts, selenonium salts, phosphonium salts, diazonium salts, paratoluenesulfonates, trichloromethyl-substituted triazines, and trichloromethyl-substituted benzenes. Examples of sulfonium salts include those represented by the formula R c 3S + X - In the formula, R c are methyl, ethyl, propyl, butyl, and other C 1~6 Alkyl groups: phenyl, naphthyl, biphenyl, tolyl, propylphenyl, decylphenyl, dodecylphenyl, and other C 1~24 may represent an aryl group or a substituted aryl group, - is SbF6 - , AsF6 - , PF6 - , BF4 - , B(C6F5)4 - , HSO4 - , ClO4 - , CF3SO3 - and other non-nucleophilic non-basic anions. Examples of iodonium salts include those of formula R c 2I + X - Examples of selenonium salts include salts represented by the formula R c 3Se + X - Examples of phosphonium salts include salts represented by the formula R c 4P + X - Examples of diazonium salts include salts represented by the formula R c N2 + X - In the formula, R c and X - is R c 3S + X -Examples of paratoluenesulfonates include those of the formula CH3C6H4SO3R c1 In the formula, R c1 represents an organic group containing an electron-withdrawing group such as a benzoylphenylmethyl group, a phthalimide group, and the like. Examples of trichloromethyl-substituted triazines include [CC13]2C3N3R c2 In the formula, R c2 represents phenyl, substituted or unsubstituted phenylethyl, substituted or unsubstituted furanylethynyl, and other electron-withdrawing groups. Examples of trichloromethyl-substituted benzenes include CCl3C6H3R c R c3 In the formula, R c is R c 3S + X - is the same as described herein for R c3 represents halogen groups, halogen-substituted alkyl groups, and other halogen-containing groups.

[0048] Examples of photoinitiators include, for example, triphenylsulfonium tetrafluoroborate, di(p-tert-butylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium hexafluoroantimonate, 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate salt, and p-chlorophenyldiazonium tetrafluoroborate.

[0049] The content of component (C) is about 0.2% to about 2% by mass, optionally about 0.2% to about 1% by mass, or optionally about 0.2% to about 0.8% by mass, of the total mass of components (A), (B), and (C). If the content of component (C) is at or above the lower limit of the above range, the curable silicone composition will be sufficiently cured. On the other hand, if the content is at or below the upper limit of the above range, the optical performance of the cured product will be improved.

[0050] The present composition contains the above-described components (A) to (C). In order to impart better mechanical strength to the cured product of the present composition, it may also contain (D) an epoxy-functional silicone other than component (B), and / or (E) an adhesion promoter, and / or (F) a photosensitizer, and / or (G) an alcohol, and / or (H) an inorganic filler.

[0051] Component (D) is an epoxy-functional silicone having the following general formula: X 1 -R 3 2SiO(SiR 3 2O) n SiR 3 2-X 1 .

[0052] In the formula, each R 3 are the same or different C 1~6 R is a monovalent aliphatic hydrocarbon group. 3 C 1~6 Examples of monovalent aliphatic hydrocarbon groups include C 11 groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0053] In the formula, each 1 are the same or different groups selected from monovalent epoxy-substituted organic groups and epoxy-functional siloxy groups represented by the general formula: X 2 -R 3 2SiO(SiR 3 2O) x SiR 3 2-R 4 -.

[0054] X 1Examples of the monovalent epoxy-substituted organic group include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 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, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0055] In the above general formula, each R 3 are the same or different C 1~6 R is a monovalent aliphatic hydrocarbon group. 3 C 1~6 Examples of monovalent aliphatic hydrocarbon groups include C 11 groups such as methyl, ethyl, propyl, butyl, and hexyl groups. 1~6 Alkyl groups; C such as vinyl, allyl, and hexenyl groups 2~6 alkenyl groups; and C groups such as 3-chloropropyl and 3,3,3-trifluoropropyl groups 1~6 Among these, methyl groups are generally preferred.

[0056] In the above general formula, R 4 is C 2~6 is an alkylene group. 4 C 2~6 Examples of alkylene groups include ethylene, methylethylene, propylene, butylene, and hexylene groups, with the ethylene group being generally preferred.

[0057] In the above general formula, X 2 is a monovalent epoxy-substituted organic group. 2Examples of the monovalent epoxy-substituted organic group include glycidoxyalkyl groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, and 5-glycidoxypentyl; 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, 3,4-epoxybutyl, and 4,5-epoxypentyl. Among these, 3,4-epoxycycloalkylalkyl groups are generally preferred.

[0058] In the above general formula, "x" is a number from about 0 to about 5, optionally from about 0 to about 2, or optionally about 0.

[0059] In the above general formula, "n" is a number from about 0 to about 10, optionally from about 0 to about 20, or optionally from about 0 to about 10. When "n" is equal to or greater than the lower limit of the above range, the elasticity and impact strength of the cured product can be improved. On the other hand, when "n" is equal to or less than the upper limit of the above range, the optical performance of the cured product can be improved.

[0060] The state of component (D) at 25°C is not limited, but it is generally a liquid. The viscosity of component (D) at 25°C is not limited, but it is generally within the range of about 5 to about 100 mPa·s. In this specification, viscosity is a value measured at 23±2°C using a Brookfield viscometer in accordance with ASTM D 1084.

[0061] The content of component (D) is not limited, but is generally about 0.1% to about 10% by mass, or optionally about 0.1% to about 5% by mass, of the total mass of components (A), (B), (C), and (D). If the content of component (D) is equal to or greater than the lower limit of the above range, the elastic modulus of the cured product can be improved. On the other hand, if the content is equal to or less than the upper limit of the above range, the elasticity and impact strength of the cured product can be improved.

[0062] Component (E) is an adhesion promoter. Examples of adhesion promoters include epoxy-functional alkoxysilanes, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyldiethoxysilane, and combinations thereof; unsaturated alkoxysilanes, such as vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxysilane, methyltrieth ... Examples of suitable adhesion promoters include hydroxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, and combinations thereof; and epoxy-functional siloxanes having silicon-bonded alkoxy groups, such as the reaction product of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane (e.g., any of those described above), or a physical blend of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane. The adhesion promoter may include a combination of an epoxy-functional alkoxysilane and an epoxy-functional siloxane. For example, the adhesion promoter is exemplified by a mixture of 3-glycidoxypropyltrimethoxysilane with the reaction product of a hydroxy-terminated methylvinylsiloxane and 3-glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinyl / dimethylsiloxane copolymer.

[0063] The content of component (E) is not limited, but is generally about 0.01 to about 5 mass% of the total mass of components (A), (B), (C), and (E), or optionally about 0.1 to about 2 mass%. If the content of component (E) is equal to or greater than the lower limit of the above range, the adhesiveness of the cured product can be improved. On the other hand, if the content is equal to or less than the upper limit of the above range, the mechanical properties of the cured product can be improved.

[0064] Component (F) is a photosensitizer. Examples of the photosensitizer of component (F) include isopropyl-9H-thioxanthen-9-one, anthrone, 1-hydroxycyclohexyl-phenyl ketone, 2,4-diethyl-9H-thioxanthen-9-one, 2-isopropylthioxanthene, 2-hydroxy-2-methyl-l-phenylpropan-l-one, 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT), pentaerythritol tetrakis[3-(3,5-di-te tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[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, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], and hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0065] The content of component (F) is not limited, but is generally within the range of about 0.001 to about 1 mass %, optionally within the range of about 0.005 to about 0.5 mass %, or optionally within the range of about 0.005 to about 0.1 mass %, of the total mass of components (A), (B), (C), and (F). When the content of component (F) is equal to or greater than the lower limit of the above range, the curability of the cured product can be improved. On the other hand, when the content is equal to or less than the upper limit of the above range, the optical clearance of the cured product can be improved.

[0066] Component (G) is an alcohol. Examples of the alcohol include monohydric alcohols such as ethyl alcohol, isopropyl alcohol, isobutyl alcohol, 1-decanol, 1-dodecanol, 1-octanol, oleyl alcohol, 1-hexadecanol, and stearyl alcohol; and polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,10-decanediol, glycerol, and pentaerythritol.

[0067] The content of component (G) is not limited, but is generally about 0.01 to about 10% by mass, or optionally about 0.1 to about 10% by mass, of the total mass of components (A), (B), (C), and (G). If the content of component (G) is at or above the lower limit of the above range, the curability of the curable silicone composition can be improved. On the other hand, if the content is at or below the upper limit of the above range, the mechanical properties of the cured product can be improved.

[0068] Component (H) is an inorganic filler for increasing the mechanical strength of the cured product. Examples of fillers for component (H) include one or more of finely divided treated or untreated precipitated silica or fumed silica, precipitated or ground calcium carbonate, zinc carbonate, clays such as finely divided kaolin, quartz powder, aluminum hydroxide, zirconium silicate, diatomaceous earth, wollastonite, pyrophyllate, and metal oxides such as fumed or precipitated titanium dioxide, cerium oxide, magnesium oxide powder, zinc oxide, and iron oxide.

[0069] The content of component (H) is not limited, but is generally within the range of about 1 to about 95 mass% of the total mass of components (A), (B), (C), and (H), optionally within the range of about 5 to about 95 mass%, or optionally within the range of about 5 to about 90 mass%. If the content of component (H) is at or above the lower limit of the above range, the electrical conductivity or thermal conductivity of the cured product can be improved. On the other hand, if the content is below the upper limit of the above range, the handleability of the curable silicone composition can be improved.

[0070] The present compositions can be cured by irradiation with UV light (i.e., ultraviolet ("UV") light). For example, low-pressure, high-pressure, or extra-high-pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, or electrodeless lamps are useful as UV lamps. The exposure dose is generally about 5 to about 6,000 mJ / cm. 2 or optionally within the range of about 10 to about 4,000 mJ / cm 2 is within the range. cured product

[0071] When the composition is cured by exposure to UV light, it forms a cured product. The cured product of the present invention has a hardness, as measured using the Shore D hardness scale specified in ASTM D2240, of at least 20 to 95, typically at least 30 to 80, and more typically at least 30 to 70. The reason for this is as follows: if the hardness of the cured product is below the lower limit of the specified range, the strength of the cured product may be insufficient. On the other hand, if the hardness exceeds the upper limit of the specified range, the flexibility of the target cured product tends to be insufficient.

[0072] To exhibit satisfactory flexibility, the cured product may have an elongation of at least 10%, as specified in ASTM D412, because below the specified range the cured product will have insufficient flexibility.

[0073] Because the cured products of the present invention are flexible and highly transparent, they are useful as optical members or parts that are transparent to light, such as visible light, infrared light, ultraviolet light, far ultraviolet light, X-rays, and lasers. The cured products of the present invention are also useful as optical members or parts that must be flexible, for example, for use in a bent or curved state, and as optical members or parts for devices involving high-energy, high-output light. Additionally, by forming the cured silicone material of the present invention into a single article or body together with any of a variety of substrates to produce a composite material, it is possible to produce an article or part having a flexible, highly transparent cured layer, and the cured layer can be expected to provide impact and stress relief functions. [Example]

[0074] The curable silicone composition and cured product of the present invention will now be described in detail using examples and comparative examples. It should be noted that in the formulas, "Me," "Pr," "Vi," "Ph," "Gly," and "Ep" represent methyl, propyl, vinyl, and phenyl groups, respectively; 3-glycidoxypropyl, and 2-(3,4-epoxycyclohexyl)ethyl groups. The structure of the epoxy-functional silicone resin used in the examples is: 13 C NMR and 29 The molecular weights of the epoxy-functional silicone resins were determined by Si NMR measurements. The weight average molecular weights of the epoxy-functional silicone resins were calculated using GPC based on comparison with polystyrene standards. The viscosities of the epoxy-functional silicones and silicone resins were measured as follows. <Viscosity>

[0075] The viscosity at 23±2° C. was measured according to ASTM D 1084 “Standard Test Methods for Viscosity of Adhesives” using a Brookfield HA or HB Type rotational viscometer (using spindle #52, 5 rpm). <Examples 1 to 7 and Comparative Examples 1 to 6>

[0076] The curable silicone compositions (% by weight) shown in Table 1 were prepared using the following components.

[0077] The following epoxy-functional silicone resin was used as component (A): (a1): An epoxy-functional silicone resin having a weight-average molecular weight of 2,000 to 6,000 and represented by the following average unit formula: (MePhSiO 2 / 2 ) 0.34 (PrSiO 3 / 2 ) 0.50 (EpSiO 3 / 2 ) 0.16

[0078] The following epoxy-functional silicone resins were used as comparisons for component (A): (a2): an epoxy-functional silicone resin having a weight-average molecular weight of 2,000 to 6,000 and represented by the following average unit formula: (MePhSiO 2 / 2 ) 0.34 (PrSiO 3 / 2 ) 0.34 (EpSiO 3 / 2 ) 0.32

[0079] The following epoxy-functional silicones were used as component (B): (b1): Epoxy-functional silicone having a viscosity of 4,000 mPa·s, a weight-average molecular weight of 12,000, and represented by the following average formula: Ep-SiMe2OSiMe2-C2H4-SiMe2O(SiMePhO) 23 SiMe2-C2H4-SiMe2OSiMe2-Ep

[0080] The following epoxy-functional silicones were used as comparisons for component (B): (b2): Epoxy-functional silicone having a viscosity of 130 mPa·s and a weight average molecular weight of 4,500, and represented by the following formula: Ep-SiMeO(SiMeO) 14 SiMe2-Ep

[0081] The following cationic photoinitiators were used as component (C): (c1): 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate salt (TR-PAG-3048 manufactured by Changzhou Tronly New Electronic Materials Co., Ltd.) (c2): Triarylsulfonium borate salt (CPI-310B manufactured by San-Apro Ltd.)

[0082] The following epoxy-functional silicones were used as component (D): (d1) An epoxy-functional silicone having a viscosity of 40 mPa·s, a weight average molecular weight of 382, ​​and represented by the following formula: Ep-SiMe2OSiMe2-Ep

[0083] The following components were used as component (E): (e1): A silicone resin having a viscosity of 4800 mPa·s, a weight average molecular weight of 2,200, and represented by the following average unit formula: (ViSiO 3 / 2 ) 0.21 (PhSiO 3 / 2 ) 0.31 (MeGlySiO 2 / 2 ) 0.48 (e2): 3-glycidoxypropyltrimethoxysilane

[0084] The following components were used as component (F): (f1): 2,4-diethyl-9H-thioxanthen-9-one (f2): 2-isopropylthioxanthene

[0085] The following component was used as component (G): (g1): 1-decanol

[0086] The curable silicone compositions were evaluated as follows. The properties of the curable silicone compositions and their cured products are shown in Table 1. <Curability of Curable Silicone Composition>

[0087] Approximately 0.1 to 3 g of the curable silicone composition was placed on a glass slide. After leveling the surface with a bar coater, the composition was applied at 5000 mW / cm 2 The curable silicone composition was passed through a metal halide UV lamp using an H bulb at a light intensity of 1000 kJ / cm. The curability of the curable silicone composition was evaluated as follows. ○○: Rapidly cured (can be cured with lower light intensity) ○: Hardened ×: Not cured <Adhesive strength>

[0088] The adhesive strength of this material is determined by measuring the amount of pull required to separate the lap shear laminate (lap shear strength). Results are reported in kgf / square centimeter. The amount of adhesive or cohesive failure is estimated. This procedure is similar to ASTM D-816, ASTM D-1002, MIL-S-8802, and ASTM C-961. <Hardness>

[0089] The indentation hardness of this material is measured using either the Shore "A" or Shore "D" durometer scale. The procedure is based on ASTM D 2240. <Stretch>

[0090] This method is applied to determine the tensile strength, elongation, set point, and modulus of elasticity of this material. The sample is pulled at a constant rate until it breaks, and the appropriate values ​​are calculated. The procedure is based on ASTM D 412. It is also similar to JIS test method K-6301, with the main difference being the calculation mode. <Appearance of the cured product>

[0091] After UV irradiation, the cured product was visually inspected. [Table 1] [Table 2] <Examples 8 and 9>

[0092] The curable silicone compositions (% by weight) shown in Table 2 were prepared using the above components and the following components:

[0093] The following component was used as component (H): (h1): Spherical aluminum oxide powder with an average particle size of 5 μm (h2): Spherical silver-coated copper powder with an average particle size of 7.5 to 9.0 μm

[0094] The curable silicone compositions were evaluated as follows. The properties of the curable silicone compositions and their cured products are shown in Table 1.

[0095] Cured samples were prepared and thermal conductivity was measured according to the steady state method of ASTM D5470.

[0096] Cured samples were prepared and electrical conductivity was calculated from the volume resistivity measured according to ASTM D257, IEC 62631-3-1. [Table 3] Industrial Applicability

[0097] The curable silicone composition of the present invention can be cured by exposure to UV light, and is therefore useful as a variety of adhesives, encapsulants, coatings, and the like for electrical and electronic components.

Claims

1. 1. A curable silicone composition comprising: (A) an epoxy-functional silicone resin represented by the average unit formula: (R13SiO1 / 2) a (R12SiO2 / 2) b (R1SiO3 / 2) c (SiO4 / 2) d an epoxy-functional silicone resin, wherein each R1 is the same or different organic group selected from a C1-6 monovalent aliphatic hydrocarbon group, a C6-10 monovalent aromatic hydrocarbon group, and a monovalent epoxy-substituted organic group, with the proviso that at least 15 mol% of all of said R1's are said C6-10 monovalent aromatic hydrocarbon groups, "a", "b", "c", and "d" are 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, and 2-30 mol% of all siloxane units have said monovalent epoxy-substituted organic group; (B) an epoxy-functional silicone represented by the general formula: X1-R22SiO (SiR22O)mSiR22-X1 In the formula, each R2 is the same or different organic group selected from a C1-6 monovalent aliphatic hydrocarbon group and a C6-10 monovalent aromatic hydrocarbon group, with the proviso that at least 10 mol% of all R2 are the C6-10 monovalent aromatic hydrocarbon group, and each X1 is the same or different group selected from a monovalent epoxy-substituted organic group and an epoxy-functional siloxy group represented by the following general formula: X2-R32SiO(SiR32O)xSiR32-R4- wherein each R3 is the same or different C1-6 monovalent aliphatic hydrocarbon group, R4 is a C2-6 alkylene group, X2 is a monovalent epoxy-substituted organic group, and "x" is a number from 0 to 5; "m" is a number from 5 to 100, and an epoxy-functional silicone in an amount of 5% to 40% by weight of the total weight of components (A), (B), and (C); (C) a cationic photoinitiator in an amount of 0.2% to 2% by weight of the total weight of components (A), (B), and (C).

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

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

4. (D) an epoxy-functional silicone represented by the general formula: X1-R32SiO(SiR32O)nSiR32-X1 In the formula, each R3 is the same or different C1-6 monovalent aliphatic hydrocarbon group, and each X1 is the same or different group selected from monovalent epoxy-substituted organic groups and epoxy-functional siloxy groups represented by the following general formula: X2-R32SiO(SiR32O)xSiR32-R4- wherein each R3 is the same or different C1-6 monovalent aliphatic hydrocarbon group, R4 is a C2-6 alkylene group, X2 is a monovalent epoxy-substituted organic group, and "x" is a number from 0 to 5; 4. The curable silicone composition of claim 1, further comprising an epoxy-functional silicone in an amount of 0.1% to 10% by weight of the total weight of components (A), (B), (C), and (D), wherein "n" is a number from 0 to 10.

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

6. 6. The curable silicone composition of claim 1 or any one of claims 2 to 5, further comprising: (E) an adhesion promoter, the adhesion promoter being in an amount of 0.01 to 5 weight percent, based on the total weight of components (A), (B), (C), and (E).

7. 7. The curable silicone composition of claim 1 or any one of claims 2 to 6, further comprising (F) a photosensitizer, the photosensitizer being in an amount of 0.001 to 0.1% by weight, based on the total weight of components (A), (B), (C), and (F).

8. 8. The curable silicone composition of claim 1 or any one of claims 2 to 7, further comprising: (G) an alcohol in an amount of 0.01 to 10 weight percent of the total weight of components (A), (B), (C), and (G).

9. 9. The curable silicone composition of claim 1 or any one of claims 2 to 8, further comprising (H) an inorganic filler in an amount of 1 to 95 weight % of the total weight of components (A), (B), (C), and (H).

10. A cured product obtained by curing the curable silicone composition according to any one of claims 1 to 9.

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