Curable hot melt silicone composition, encapsulant, hot melt adhesive, and optical semiconductor device

Abstract

The present invention relates to a hot melt curable silicone composition comprising (A) an MQ resin-like alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (B) a linear alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule and having a viscosity of 300 mPa.s or more at 25 DEG C; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (D) an MQ resin-like organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms per molecule; and (E) a curing catalyst, wherein: (i) the content of the MQ resin-like organohydrogenpolysiloxane (D) is 45 mass% or more with respect to the total mass of organopolysiloxane having silicon atom-bonded hydrogen atoms; (ii) the amount of aryl groups in the total silicon atom-bonded organic groups in the total organopolysiloxane component is 10 mol% or less; and (iii) the ratio of the mass of component (A) to the total mass of component (A) and component (B) is 0.6 or more.

Description

Technical Field

[0001] This invention relates to a heat-curable silicone composition, and more particularly to a heat-curable silicone composition suitable as a sealing material for optical semiconductors. The invention also relates to an optical semiconductor device sealed with a sealing material composed of a cured product of such a heat-curable silicone composition. This application claims priority based on Japanese Patent Application No. 2023-191573, filed on November 9, 2023, the contents of which are incorporated herein by reference. Background Technology

[0002] Upon curing, the curable silicone composition forms a cured product with excellent heat resistance, cold resistance, electrical insulation properties, weather resistance, water resistance, and transparency, and is therefore used in a wide range of industrial applications. In particular, compared with other organic materials, these cured products are less prone to discoloration, and their physical properties, such as durability, deteriorate less, and therefore they are used in optical materials, and are particularly widely used as silicone sealing materials in optical semiconductor devices such as light-emitting diodes (LEDs).

[0003] In addition, hot melt silicones are curable, non-fluid at room temperature, can be formed into sheets or films, and melt into fluids when heated. They have been used as sealing materials for semiconductor devices or as hot melt adhesives.

[0004] For example, Patent Document 1 describes a hot-melt silicone that is non-fluid at 25°C and has a pressure of 5,000 Pa at 100°C. The hot-melt silicone, with a melt viscosity of S or lower, is obtained by: (A) an alkenyl-containing organopolysiloxane in which 10 mol% or more of the total silicon atoms bonded to the organic groups are phenyl, and (B) an organopolysiloxane having at least two silicon atoms bonded to hydrogen atoms in one molecule (in an amount sufficient to provide 0.2 to 0.7 mol of silicon atoms bonded to hydrogen atoms per mol of alkenyl group in component (A)) undergoing a hydrosilylation reaction in the presence of (C) a hydrosilylation catalyst (in an amount sufficient to promote the hydrosilylation reaction between component (A) and component (B).

[0005] Patent document 2 also describes a curable silicone composition formed from: at least 100 parts by mass of (A) an organopolysiloxane represented by the following average unit formula: (R 1 3SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 3 SiO 3 / 2 )c (SiO 4 / 2 ) d (R 4 O 1 / 2 ) e (In this formula, R) 1 R 2 and R 3 It is phenyl, C1-6 alkyl, or C2-6 alkenyl, and they can be the same or different, provided that R 1 40 mol% or less, R 2 30 mol% or more and R 3 10 mol% or less is alkenyl, R 1 R 2 and R 3 30 to 60 mol% of the total amount is phenyl, R 4 It is a hydrogen atom or a C1-6 alkyl group, where a is a number from 0 to 0.2, b is a number from 0.2 to 0.5, c is a number from 0.3 to 0.8, d is a number from 0 to 0.5, e is a number from 0 to 0.1, c + d is a number from 0.3 to 0.8, and a + b + c + d = 1); 0 to 150 parts by mass of (B) an organopolysiloxane represented by the following average unit formula: (R 5 3SiO 1 / 2 ) f (R 5 2SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (R 6 O 1 / 2 ) j (In this formula, R) 5 It is phenyl, C1-6 alkyl, or C2-6 alkenyl, which can be the same or different, provided that all R... 5 10 to 70 mol% are phenyl and all R 5 At least one of them is an alkenyl group, R 6 (a) is a hydrogen atom or a C1-6 alkyl group, f is a number from 0.01 to 0.3, g is a number from 0.4 to 0.99, h is a number from 0 to 0.2, i is a number from 0 to 0.2, j is a number from 0 to 0.1, h + i is a number from 0 to 0.2, and f + g + h + i = 1); (C) an organohydrogen polysiloxane represented by the following average structural formula: R 7 k H l SiO (4-k-l) / 2 (In this formula, R) 7It is phenyl or C1-6 alkyl, provided that all R 7 10 to 70 mol% of which are phenyl, k is a number from 1.0 to 2.5, l is a number from 0.01 to 0.9, and k + l is a number from 1.5 to 3.0 (the amount is the total alkenyl group per mole of component (A) and component (B), in which the hydrogen atoms bonded to silicon atoms in this component are 0.5 to 2.0 moles); and (D) a hydrosilylation catalyst.

[0006] Patent document 3 also describes a solvent-free, hot-melt curable silicone composition comprising (A) an alkenyl-containing organopolysiloxane having at least two alkenyl groups in one molecule; (B) a resinous organohydrogen polysiloxane having at least two silicon atoms bonded in one molecule, comprising 0.1 to 5% by mass relative to the total mass of the composition; and (C) an additive represented by the following average unit formula (C-1): (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (In this formula, R) 1 It is an alkyl, aryl, alkenyl, aralkyl, or epoxy-containing organic group, or an alkoxy group, which may be the same or different, provided that at least one R is present. 1 It is alkenyl and has at least one R 1 (a) is an organic group containing an epoxy group, where a, b, and c are 0 ≤ a ≤ 1.0, 0 ≤ b ≤ 1.0, 0 ≤ c < 0.9 respectively, and are numbers that satisfy a + b + c = 1); (D) a hydrosilylation catalyst; and (E) silicon dioxide.

[0007] However, the problem with conventional hot-melt curable silicone compositions containing high levels of aryl groups is that they discolor when heated, resulting in reduced transparency. Existing technical documents Patent documents

[0008] [Patent Document 1] WO 2015 / 194158 [Patent Document 2] WO 2016 / 035285 [Patent Document 3] Japanese Unexamined Patent Publication No. 2021-21058 Summary of the Invention The problem to be solved by the present invention

[0009] The purpose of this invention is to provide a hot-melt curable silicone composition having a low aryl content and being able to form a cured product with excellent transparency and mechanical strength.

[0010] Another object of the present invention is to provide a sealing material or hot melt adhesive containing the hot melt curable silicone composition of the present invention. Yet another object of the present invention is to provide an optical semiconductor device sealed with the sealing material of the present invention. Problem-solving methods

[0011] As a result of extensive research to solve the above problems, the inventors completed the present invention when they discovered that a curable organopolysiloxane composition containing at least components (A) to (E) according to the present invention and satisfying the following conditions (i) to (iii) exhibits hot-melt properties and is able to form a cured product with excellent transparency and mechanical strength.

[0012] Therefore, the present invention relates to a hot-melt curable silicone composition comprising: (A) MQ resin containing alkenyl groups, each molecule having at least two alkenyl groups; (B) A straight-chain alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher; (C) Cyclic alkenyl-containing organopolysiloxanes having at least two alkenyl groups per molecule; (D) MQ resin-based organohydrogen polysiloxanes with at least two silicon atoms bonded to hydrogen atoms per molecule; and (E) Curing catalyst, in (i) The content of MQ resin-based organohydrogen polysiloxane (D) is 45% by mass or more relative to the total mass of organohydrogen atoms bonded to silicon atoms; (ii) The amount of aryl groups in the total silicon-bonded organic groups of the total organic polysiloxane component is 10 mol% or less; and (iii) The mass of component (A) accounts for 0.6 or more of the total mass of components (A) and (B).

[0013] The composition preferably further comprises at least one maleate ester.

[0014] The linear alkenyl-containing organopolysiloxane of component (B) preferably further contains 50 or more siloxane units.

[0015] The mass ratio of component (B) to the total mass of the total alkenyl-containing organopolysiloxane is preferably 0.5 or less.

[0016] The mass ratio of component (C) to the total mass of components (A) to (C) is preferably 0.001 or greater.

[0017] The composition preferably further contains (F) a cerium-containing organopolysiloxane.

[0018] The molar ratio (H / Alk) of hydrogen atoms bonded to silicon atoms to alkenyl groups bonded to silicon atoms in the total organic polysiloxane component is less than 1.2.

[0019] Based on the total mass of the composition, the content of linear organohydrogen polysiloxane having 20 or more siloxane units is 2.5% by mass or less.

[0020] The present invention also relates to a sealing material or hot melt adhesive comprising a hot melt curable silicone composition according to the present invention.

[0021] The present invention also relates to an optical semiconductor device sealed with a sealing material according to the present invention. Invention Effects

[0022] The present invention provides a hot-melt curable silicone composition having a low aryl content and being able to form a cured product with excellent transparency and mechanical strength. Detailed Implementation

[0023] [Hot-Melt Curable Silicone Composition] The hot-melt curable silicone composition according to the present invention relates to a hot-melt curable silicone composition comprising at least: (A) MQ resin containing alkenyl groups, each molecule having at least two alkenyl groups; (B) A straight-chain alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher; (C) Cyclic alkenyl-containing organopolysiloxanes having at least two alkenyl groups per molecule; (D) MQ resin-based organohydrogen polysiloxanes with at least two silicon atoms bonded to hydrogen atoms per molecule; and (E) Curing catalyst, in (i) The content of MQ resin-based organohydrogen polysiloxane (D) is 45% by mass or more relative to the total mass of organohydrogen atoms bonded to silicon atoms; (ii) The amount of aryl groups in the total silicon-bonded organic groups of the total organic polysiloxane component is 10 mol% or less; and (iii) Component (A) accounts for 60% or more of the total mass of components (A) and (B).

[0024] The components of the hot-melt curable silicone composition of the present invention are described in detail below.

[0025] (A) MQ resin containing alkenyl groups, each molecule having at least two alkenyl groups; Component (A) is an alkenyl-containing organopolysiloxane containing at least two alkenyl groups in a molecule. The hot-melt curable silicone composition according to the invention may contain one type of alkenyl-containing MQ resin (A), or may contain two or more types of alkenyl-containing MQ resin (A). In this specification, "MQ resin" means composed solely of R3-SiO2. 1 / 2 The siloxane unit (M unit) and SiO2 are represented. 4 / 2 The term refers to organopolysiloxanes composed of siloxane units (Q units). In this specification, R in the siloxane unit refers to an organic group bonded to a silicon atom, such as a monovalent hydrocarbon group.

[0026] Examples of alkenyl groups contained in component (A) include C2-12 alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, wherein vinyl is preferred.

[0027] Examples of silicon-bonded groups (other than alkenyl groups) in component (A) include halogen-substituted or unsubstituted monovalent hydrocarbon groups (other than alkenyl groups), such as C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 arylalkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine, chlorine, and bromine atoms. The silicon atoms in component (A) may have small amounts of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the purpose of the invention is not impaired. The silicon-bonded groups (other than alkenyl groups) in component (A) are preferably selected from C1-6 alkyl groups, and particularly from methyl groups. In one embodiment, component (A) does not contain epoxy-containing organic groups.

[0028] In a preferred embodiment of the present invention, the MQ resin-based organohydrogen polysiloxane of component (A) can preferably be represented by the following average unit formula (I): Average unit form (I): (R) 1 3SiO1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u (In this formula, R) 1 Indicates whether a monovalent hydrocarbon group is halogenated or unsubstituted, and these groups may be the same or different, provided that there are at least two R groups in a molecule. 1 It is an alkenyl group, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t + u = 1. The symbol u represents the number of (XO) groups when the total number of silicon atoms is 1 (the ratio of the number of (XO) groups to the total number of silicon atoms). In this application, "monotype" indicates that it includes (SiO) groups. x / 2 The chemical formula of a siloxane unit is represented by (x is an integer from 1 to 4), and the term "structural formula" indicates a chemical formula that does not include any such siloxane unit.

[0029] In the above equation (I), R 1 Examples of halogen-substituted or unsubstituted monovalent hydrocarbon groups include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 arylalkyl groups such as benzyl, phenethyl, and phenylpropyl; C2-12 alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and any of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, chlorine, and bromine atoms. 1 Preferably selected from C1-6 alkyl groups, and particularly methyl or C2-6 alkenyl groups, wherein vinyl groups are preferred.

[0030] In formula (I) above, X is a hydrogen atom or an alkyl group. Preferred examples of alkyl groups represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl.

[0031] In equation (I), s is preferably in the range of 0.2 ≤ s ≤ 0.8, more preferably in the range of 0.3 ≤ s ≤ 0.7, and even more preferably in the range of 0.35 ≤ s ≤ 0.65. In equation (I), t is preferably in the range of 0.2 ≤ t ≤ 0.8, more preferably in the range of 0.3 ≤ t ≤ 0.7, and particularly in the range of 0.35 ≤ t ≤ 0.65. In equation (I), u is preferably in the range of 0 ≤ u ≤ 0.3, more preferably in the range of 0 ≤ u ≤ 0.2, and particularly in the range of 0 ≤ u ≤ 0.1.

[0032] The content of alkenyl groups in the total silicon-bonded organic groups of the MQ resin-based alkenyl organopolysiloxane of component (A) is not particularly limited, but may be, for example, 1 mol% or more, preferably 2 mol% or more, and more preferably 3 mol% or more, of the total silicon-bonded organic groups, and may be 30 mol% or less, preferably 20 mol%, and more preferably 10 mol% or less, of the total silicon-bonded organic groups. The content of alkenyl groups may be determined by means of analysis such as Fourier transform infrared spectrophotometry (FT-IR) or nuclear magnetic resonance (NMR), or by means of titration methods described below. In this specification, numerical ranges may be established using any combination of upper and lower limits of numerical ranges.

[0033] A method for quantifying alkenyl groups in a component using titration will be described. The alkenyl content in an organopolysiloxane component can be accurately quantified using a titration method commonly known as the Wijs method. The principle is described below. First, the alkenyl group in the organopolysiloxane starting material is subjected to an addition reaction with iodine monochloride as shown in formula (1). Next, excess iodine monochloride is reacted with potassium iodide according to the reaction shown in formula (2), thereby releasing iodine. The released iodine is then titrated with a sodium thiosulfate solution. Equation (1): CH2 = CH- + 2ICl → CH2I-CHCl- + ICl (excess) Equation (2): ICl + KI → I2 + KCl The amount of alkenyl groups in the component can be quantified by the difference between the amount of sodium thiosulfate required for titration and the titration amount of a blank solution prepared separately.

[0034] According to one embodiment of the invention, the MQ resin-based organohydrogen polysiloxane of component (A) is characterized by a low aryl content. The aryl content in component (A) (mol% of aryl groups in total silicon-bonded organic groups) can be, for example, 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and particularly 1 mol% or less. In a preferred embodiment, component (A) does not contain aryl groups. In this specification, the aryl content can be determined, for example, by analysis such as Fourier transform infrared spectrophotometry (FT-IR) or nuclear magnetic resonance (NMR).

[0035] The weight-average molecular weight of the MQ resin-based organohydrogen polysiloxane in component (A) is not particularly limited, but is in the range of 1,000 to 100,000. In this specification, the weight-average molecular weight can be determined by GPC.

[0036] The content of component (A) is not particularly limited, but is generally 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more, based on the total mass of the hot-melt curable silicone composition of the present invention. The content of component (A) is also 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, based on the total mass of the hot-melt curable silicone composition.

[0037] (B) A linear-chain alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher. Component (B) is a linear alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher. The hot-melt curable silicone composition according to the invention may contain one type of linear alkenyl-containing organopolysiloxane (B), or may contain two or more types of linear alkenyl-containing organopolysiloxanes (B).

[0038] The alkenyl and silicon atom bonded groups (other than alkenyl groups) contained in component (B) may be the same as those described above for component (A), and therefore the same details as those already described for component (A) may be applied.

[0039] The linear alkenyl-containing organopolysiloxane of component (B) has a viscosity of 300 mPa·s or higher at 25°C. More preferably, the linear alkenyl-containing organopolysiloxane of component (B) has a viscosity of 500 mPa·s or higher at 25°C, and even more preferably 800 mPa·s or higher. The upper limit of the viscosity of the linear alkenyl-containing organopolysiloxane of component (B) at 25°C is not particularly limited, but is typically 100,000 mPa·s or lower, and preferably 70,000 mPa·s or lower. In this specification, the viscosity of the organopolysiloxane component can be determined at 25°C using a rotational viscometer according to JIS K7117-1.

[0040] In an ideal embodiment, the linear alkenyl-containing organopolysiloxane of component (B) contains 50 or more siloxane units. In a preferred embodiment, the linear alkenyl-containing organopolysiloxane of component (B) contains 75 to 1,000 siloxane units, more preferably 125 to 900 siloxane units, and even more preferably 150 to 800 siloxane units.

[0041] In a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (B) can preferably be represented by the following average structural formula (II-a). Average structural formula (II-a): R 1 3SiO(R 1 SiO 2 / 2 ) n SiR 1 3 (In equation (II-a), R) 1 It is a halogen-substituted or unsubstituted monovalent hydrocarbon group, which can be the same or different, and at least two R groups in one molecule. 1 It is an alkenyl group, and n is a number that results in a viscosity of 300 mPa·s or higher at 25°C; for example, 50 to 1,000.

[0042] In equation (II-a) above, R 1 The halogenated or unsubstituted monovalent hydrocarbon group represented can be the same as those in formula (I) above.

[0043] In the above formula (II-a), n is preferably 75 to 900, more preferably 125 to 800, and even more preferably 150 to 700.

[0044] In a preferred embodiment of the present invention, the linear organopolysiloxane containing alkenyl groups in component (B) can be a linear organopolysiloxane with alkenyl groups at both ends of the molecular chain, containing alkenyl groups at both molecular ends. The linear organopolysiloxane of component (B) has alkenyl groups at the molecular side chains (i.e., composed of R2-SiO2). 2 / 2 The siloxane unit (D unit) may or may not have an alkenyl group, but preferably does not have an alkenyl group.

[0045] Therefore, in a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (B) can preferably be represented by the following average structural formula (II-b). Average structural formula (II-b): R 1 3SiO(R 2 2SiO 2 / 2 ) n SiR 1 3 (In equation (II-b), R) 1 It is a halogenated or unsubstituted monovalent hydrocarbon group, which can be the same or different, provided that there are at least two R groups in a molecule. 1 It is an alkenyl group, R 2 It is an alkyl group, and n is a number that results in a viscosity of 300 mPa·s or higher at 25°C; for example, 50 to 1,000.

[0046] In equation (II-b) above, R 1 Examples of alkenyl groups include C2-12 alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, or dodecenyl, with vinyl being preferred.

[0047] In equation (II-b) above, R 2 Examples of alkyl groups are not particularly limited, but include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl, wherein methyl is preferred.

[0048] In the above formula (II-b), n is preferably 75 to 900, more preferably 125 to 800, and even more preferably 150 to 700.

[0049] The content of alkenyl groups in the linear organopolysiloxane of component (B) (mol% of alkenyl groups in total silicon-bonded organic groups) can be designed as needed, but is typically 0.1 mol% or more and 1 mol% or less.

[0050] According to one embodiment of the invention, the linear alkenyl-containing organopolysiloxane of component (B) is characterized by a low aryl content. The aryl content in component (B) (mol% of aryl groups in total silicon-bonded organic groups) can be, for example, 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and particularly 1 mol% or less. In a preferred embodiment, component (B) does not contain aryl groups.

[0051] The content of the linear alkenyl-containing organopolysiloxane of component (B) is not particularly limited, but is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, of the total mass of the thermomeltable curable silicone composition based on the present invention. The content of component (B) is also preferably 40% by mass or less, and more preferably 35% by mass or less, of the total mass of the thermomeltable curable silicone composition based on the present invention.

[0052] In this invention, (iii) component (A) accounts for 60% or more of the total mass of components (A) and (B). Component (A) typically accounts for less than 100% of the total mass of components (A) and (B), preferably less than 90% of the total mass, more preferably 80% of the total mass or less, and even more preferably 70% of the total mass or less.

[0053] In another embodiment of the invention, component (B) accounts for 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more of the total alkenyl-containing organopolysiloxanes contained in the hot-melt silicone composition of the invention. The proportion of component (B) relative to the total alkenyl-containing organopolysiloxanes contained in the hot-melt silicone composition of the invention is typically 50% by mass or less, and preferably 40% by mass or less.

[0054] (C) Cyclic alkenyl-containing organopolysiloxanes having at least two alkenyl groups per molecule Component (C) is a cyclic alkenyl-containing organopolysiloxane having at least two alkenyl groups in a molecule. The hot-melt curable silicone composition according to the invention may contain one type of cyclic alkenyl-containing organopolysiloxane (C), or may contain two or more types of cyclic alkenyl-containing organopolysiloxanes (C).

[0055] The alkenyl and silicon atom bonded groups (other than alkenyl groups) contained in component (C) may be the same as those in component (A) above.

[0056] The cyclic alkenyl-containing organopolysiloxane of component (C) can preferably be represented by the following: Average structural formula (III): (R) 1 2SiO) n (In equation (III), R) 1 It is a halogenated or unsubstituted monovalent hydrocarbon group, which can be the same or different, provided that there are at least two R groups in a molecule. 1 It is an alkenyl group, and n is 4 to 20.

[0057] In equation (III) above, R 1 The halogenated or unsubstituted monovalent hydrocarbon group can be related to R in formula (I) above. 1 Those are the same.

[0058] In equation (III) above, n is, for example, 4 to 15, preferably 4 to 10, and more preferably 4 to 6.

[0059] The content of alkenyl groups in the total silicon atoms bonded to the organic groups of the cyclic alkenyl-containing organopolysiloxane of component (C) can be designed as needed, but is typically 20 mol% or more, preferably 30 mol% or more, and more preferably 40 mol% or more, and can be 80 mol% or less, preferably 70 mol% or less, and more preferably 60 mol% or less.

[0060] According to one embodiment of the invention, the cyclic alkenyl-containing organopolysiloxane of component (C) is characterized by a low aryl content. The aryl content in component (C) (mol% of aryl groups in total silicon-bonded functional groups) can be, for example, 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and particularly 1 mol% or less. In a preferred embodiment, component (C) does not contain aryl groups.

[0061] The content of the cyclic alkenyl-containing organopolysiloxane in component (C) is not particularly limited, but the total mass of the hot-melt silicone composition of the present invention is, for example, 0.05% by mass or more, more preferably 0.1% by mass or more, and typically 10% by mass or less, preferably 5% by mass or less, and more preferably 3% by mass or less.

[0062] In a preferred embodiment of the invention, the mass of component (C) as a percentage of the total mass of components (A) to (C) is 0.001 or greater, more preferably 0.002 or greater, and even more preferably 0.004 or greater. The mass of component (C) as a percentage of the total mass of components (A) to (C) is typically less than 0.1, preferably 0.05 or less, and even more preferably 0.03 or less.

[0063] In another embodiment of the invention, the mass ratio of component (C) to the total mass ratio of alkenyl-containing organopolysiloxanes contained in the hot-melt silicone composition of the invention is 0.001 or greater, more preferably 0.002 or greater, and even more preferably 0.004 or greater. The mass ratio of component (C) to the total mass ratio of alkenyl-containing organopolysiloxanes contained in the hot-melt silicone composition of the invention is typically less than 0.1, preferably 0.05 or less, and even more preferably 0.03 or less.

[0064] (D) MQ resin-based organohydrogen polysiloxanes with at least two silicon atoms bonded to hydrogen atoms per molecule. Component (D) is a MQ resin-based organohydrogen polysiloxane having at least two silicon atoms bonded to hydrogen atoms in a molecule. The hot-melt curable silicone composition according to the invention may contain one type of MQ resin-based organohydrogen polysiloxane (D), or may contain two or more types of MQ resin-based organohydrogen polysiloxane (D).

[0065] Examples of silicon-bonded groups (other than the hydrogen atoms bonded to silicon atoms) in component (D) include halogen-substituted or unsubstituted monovalent hydrocarbon groups (other than alkenyl groups), such as C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine, chlorine, and bromine atoms. The silicon atoms in component (D) may have small amounts of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the purpose of the invention is not impaired therefrom. The silicon-bonded groups in component (D) (other than the hydrogen atoms bonded to silicon atoms) are preferably selected from C1-6 alkyl groups, and particularly from methyl groups.

[0066] In a preferred embodiment of the invention, the MQ resin-based organohydropolysiloxane of component (D) can preferably be represented by the following average unit formula (IV): Average unit form (IV): (R) 4 3SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In this formula, R 4 It is a halogen-substituted or unsubstituted monovalent hydrocarbon group (except for alkenyl groups), which can be the same or different, provided that there are at least two R groups in a molecule. 4 It is a hydrogen atom, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t + u = 1. The symbol u represents the number of (XO) groups when the total number of silicon atoms is 1 (the proportion of (XO) groups to the total number of silicon atoms).

[0067] In equation (IV) above, R 4 Examples of halogen-substituted or unsubstituted monovalent hydrocarbon groups (other than alkenyl groups) include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, chlorine, and bromine atoms. R 4 It may be in small amounts of hydroxyl or alkoxy groups, such as methoxy and ethoxy, provided that the purpose of the invention is not impaired. 4 Preferably, it is a C1-6 alkyl group, and especially a methyl group.

[0068] In formula (IV) above, X is a hydrogen atom or an alkyl group. Preferred examples of alkyl groups represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl.

[0069] In equation (IV) above, s is preferably in the range of 0.3 ≤ s ≤ 0.8, more preferably in the range of 0.4 ≤ s ≤ 0.7, and even more preferably in the range of 0.5 ≤ s ≤ 0.65. In equation (IV) above, t is preferably in the range of 0.2 ≤ t ≤ 0.7, more preferably in the range of 0.3 ≤ t ≤ 0.6, and particularly in the range of 0.35 ≤ t ≤ 0.5. In equation (IV) above, u is preferably in the range of 0 ≤ u ≤ 0.3, more preferably in the range of 0 ≤ u ≤ 0.2, and particularly in the range of 0 ≤ u ≤ 0.1.

[0070] The weight-average molecular weight of the MQ resin-based organohydrogen polysiloxane in component (D) is not particularly limited, but is, for example, in the range of 1,000 to 100,000.

[0071] According to one embodiment of the invention, the MQ resin-based organohydrogen polysiloxane of component (D) is characterized by a low aryl content. The aryl content in component (D) (mol% of aryl groups in total silicon-bonded organic groups) is, for example, 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, and particularly 1 mol% or less. In a preferred embodiment, component (D) does not contain aryl groups.

[0072] The content of component (D) is not particularly limited, but is preferably 1% by mass or more based on the total mass of the hot-melt curable silicone composition of the present invention, more preferably 2% by mass or more, and even more preferably 3% by mass or more. The content of component (D) is also preferably 30% by mass or less based on the total mass of the hot-melt curable silicone composition, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0073] The content of MQ resin-based organohydrogen polysiloxane in component (D) is 45% by mass or more, and preferably 50% by mass or more, based on the total organohydrogen polysiloxane contained in the hot melt curable silicone composition.

[0074] In an ideal embodiment of the invention, the molar ratio (H / Alk) of silicon-bonded hydrogen atoms to silicon-bonded alkenyl groups in the total organopolysiloxane component of the thermomeltable curable silicone composition is such that the amount of silicon-bonded hydrogen atoms is less than 1.2 mol / mol silicon-bonded alkenyl groups. The molar ratio (H / Alk) of silicon-bonded hydrogen atoms to silicon-bonded alkenyl groups in the organopolysiloxane component is less than 1.2, and is typically 0.5 or greater, more preferably 0.7 or greater, and even more preferably 0.8 or greater.

[0075] (Other organopolysiloxane components) (G) An organohydrogen polysiloxane with at least two silicon atoms bonded to hydrogen atoms per molecule, which differs from component (D). The hot-melt curable silicone composition of the present invention may contain (G) an organohydrogen polysiloxane having at least two silicon atoms bonded to hydrogen atoms per molecule as another organohydrogen polysiloxane component, which is different from component (D). The hot-melt curable silicone composition according to the present invention may contain one type of organohydrogen polysiloxane (G), or may contain two or more types of organohydrogen polysiloxane (G).

[0076] Examples of molecular structures for component (G) include straight-chain, partially branched straight-chain, branched, resinous, cyclic, and three-dimensional network structures. Component (G) may be one type of organohydrogen polysiloxane having such a molecular structure, or it may be a mixture of two or more organohydrogen polysiloxanes having such a molecular structure. The hot-melt curable silicone composition of the present invention preferably contains a straight-chain organohydrogen polysiloxane as component (G). Component (G) is not MQ resinous. In this specification, the term "resinous" means having a branched or three-dimensional network structure in its molecular structure. In one embodiment, "resinous" refers to an organopolysiloxane wherein R-SiO 3 / 2 The siloxane unit (T unit) and the siloxane unit represented by SiO2 are shown. 4 / 2 The indicated siloxane unit (Q unit) represents 10% or more of the total siloxane units in a molecule. Partially branched straight-chain structures are not considered resinous.

[0077] The same description above of silicon-bonded groups (other than silicon-bonded hydrogen atoms) in component (D) can be applied to silicon-bonded groups (other than silicon-bonded hydrogen atoms) in component (G).

[0078] According to one embodiment of the present invention, when component (G) contains a linear organohydrogen polysiloxane, the linear organohydrogen polysiloxane of component (G) can preferably be represented by the following average structural formula (V): Average structural formula (V): R 4 3SiO(R 4 2SiO 2 / 2 ) n SiR 4 3 In equation (V), R 4 It is a hydrogen atom, or a halogen-substituted or unsubstituted monovalent hydrocarbon group (except for alkenyl groups), which can be the same or different, provided that there are at least two R groups in a molecule. 4 It is a hydrogen atom, and n is 1 to 100.

[0079] In the above equation (V), R 4 The halogenated or unsubstituted monovalent hydrocarbon group can be related to R in formula (IV) above. 4 Those are the same.

[0080] In the above formula (V), n is preferably 1 to 20, more preferably 1 to 15, even more preferably 1 to 10, and particularly preferably 1 to 5.

[0081] In a specific embodiment of the invention, the hot-melt curable silicone composition of the present invention is characterized by a low content of long-chain linear organohydrogen polysiloxanes. In this embodiment, for example, based on the total mass of the composition, the content of linear organohydrogen polysiloxanes represented by formula (IV) (where n is 20 or greater, or it has 20 or more siloxane units) may be 10% by mass or less, more preferably 5% by mass or less, even more preferably 2.5% by mass or less, and particularly preferably 1% by mass or less. In another specific embodiment, the hot-melt curable silicone composition of the present invention does not contain any linear organohydrogen polysiloxanes represented by formula (IV), where n is 20 or greater, or it has 20 or more siloxane units.

[0082] In a preferred embodiment of the invention, the linear organohydrogen polysiloxane of component (G) contains hydrogen atoms bonded to silicon atoms at both ends of the molecular chain. The linear organohydrogen polysiloxane of component (G) has hydrogen atoms bonded to silicon atoms in the M unit, and may or may not contain hydrogen atoms bonded to silicon atoms in the D unit, but preferably does not contain hydrogen atoms bonded to silicon atoms.

[0083] The linear organohydrogen polysiloxane of component (G) preferably has aryl groups bonded to silicon atoms in its molecular side chains. The linear organohydrogen polysiloxane of component (G) may or may not contain aryl groups at the molecular ends, but preferably does not. In a preferred embodiment, the organohydrogen polysiloxane of component (G) contains Ar₂SiO₂. 2 / 2 The structural unit (where Ar represents aryl) is represented by two aryl groups that are substituted on a single silicon atom.

[0084] In one embodiment of the invention, when the linear organohydrogen polysiloxane of component (G) contains aryl groups, the content of aryl groups in the total silicon atom-bonded organic groups is not particularly limited, but may be, for example, 10 mol% or more of the total amount of silicon atom-bonded organic groups, preferably 15 mol% or more, and more preferably 20 mol% or more, and may be 50 mol% or less of the total amount of silicon atom-bonded organic groups, preferably 40 mol% or less, and more preferably 30 mol% or less.

[0085] The content of component (G) is not particularly limited, but it may be included in an amount preferably 1% or more by mass, more preferably 2% or more by mass, and preferably 15% or less by mass, more preferably 10% or less by mass, and even more preferably 5% or less by mass, based on the total mass of the hot melt curable silicone composition of the present invention.

[0086] (H) Epoxy-containing organopolysiloxanes The hot-melt curable silicone composition according to the invention may contain other organopolysiloxanes, such as epoxy-containing organopolysiloxanes, as additives. The epoxy-containing organopolysiloxane (H) may preferably be a tackifier. The epoxy-containing organopolysiloxane differs from components (A) to (D) and (G) in that it contains an epoxy-containing organic group as an organic group bonded to at least one silicon atom.

[0087] Examples of molecular structures containing epoxy groups are linear, partially branched linear, branched, resinous, cyclic, and three-dimensional network structures, with resinous epoxy-containing organopolysiloxanes being preferred. The curable silicone composition according to the invention may contain one type of epoxy-containing organopolysiloxane, or may contain a combination of two or more types of epoxy-containing organopolysiloxanes.

[0088] The epoxy-containing organopolysiloxane may preferably contain an alkenyl group, examples of which include C2-12 alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, wherein vinyl is preferred, and may also contain an epoxy-containing organic group, examples of which include glycidoxyalkyl groups such as 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl; epoxycycloalkylalkyl groups such as 2-(3,4-epoxycyclohexyl)-ethyl and 3-(3,4-epoxycyclohexyl)-propyl; and epoxyalkyl groups such as 3,4-epoxybutyl and 7,8-epoxyoctyl, wherein glycidoxyalkyl is preferred, and 3-glycidoxypropyl is particularly preferred.

[0089] Examples of silicon-bonded groups (other than alkenyl and epoxy-containing organic groups) in epoxy-containing organopolysiloxanes include halogen-substituted or unsubstituted monovalent hydrocarbon groups (other than alkenyl and epoxy-containing organic groups), such as C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine, chlorine, and bromine atoms, wherein C1-12 alkyl groups and, in particular, methyl groups are preferred.

[0090] Resinous, epoxy-containing organopolysiloxanes are preferably represented by the following average unit formula (VI): (R 5 3SiO 1 / 2 ) f (R 5 2SiO2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (XO 1 / 2 ) j (In equation (VI), R) 5 Each is independently a halogenated or unsubstituted monovalent hydrocarbon group, provided that at least one R 5 It is alkenyl, and at least one R 5 X is an organic group containing an epoxy group, where X is a hydrogen atom or an alkyl group, 0 ≤ f < 1, 0 ≤ g < 1, 0 ≤ h < 0.9, 0 ≤ i < 0.5, and 0 ≤ j < 0.4, f + g + h + i + j = 1.0, and h + i > 0).

[0091] In equation (VI) above, R 5 Examples of halogen-substituted or unsubstituted monovalent hydrocarbon groups include the alkenyl groups described above, epoxy-containing organic groups, and other monovalent hydrocarbon groups. In formula (VI) above, X is a hydrogen atom or an alkyl group. Preferred examples of alkyl groups represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl.

[0092] In equation (VI) above, f is preferably in the range of 0 ≤ f ≤ 0.3, more preferably in the range of 0 ≤ f ≤ 0.2, and even more preferably in the range of 0 ≤ f ≤ 0.1. In equation (VI) above, g is preferably in the range of 0.3 ≤ g ≤ 0.9, more preferably in the range of 0.4 ≤ g ≤ 0.8, and particularly in the range of 0.5 ≤ g ≤ 0.7. In equation (VI) above, h is preferably in the range of 0.1 ≤ h ≤ 0.6, more preferably in the range of 0.2 ≤ h ≤ 0.5, and particularly in the range of 0.3 ≤ h ≤ 0.4. In equation (VI) above, i is preferably in the range of 0 ≤ i ≤ 0.3, more preferably in the range of 0 ≤ i ≤ 0.2, and particularly in the range of 0 ≤ i ≤ 0.1. In the above formula (VI), j is preferably in the range of 0 ≤ j ≤ 0.3, more preferably in the range of 0 ≤ j ≤ 0.2, and particularly in the range of 0 ≤ j ≤ 0.1.

[0093] In a preferred embodiment of the present invention, the resinous epoxy-containing organopolysiloxane (H) has g and h greater than 0 in formula (VI), that is, it contains R2-SiO 2 / 2 The siloxane unit (D unit) and the R-SiO2 unit are represented. 3 / 2 The term refers to the siloxane unit (T unit). Resinous, epoxy-containing organopolysiloxanes may or may not contain R3-SiO2. 1 / 2 The term refers to the siloxane unit (M unit). Resinous, epoxy-containing organopolysiloxanes may or may not contain, but preferably do not contain, components derived from SiO₂. 4 / 2 The siloxane unit (Q unit) is represented. In a preferred embodiment, the resinous epoxy-containing organopolysiloxane (H) consists only of D units and T units.

[0094] In a preferred embodiment of the invention, the epoxy-containing organopolysiloxane has an epoxy-containing organic group as a side group on the molecular side chain. The epoxy-containing organopolysiloxane is preferably formed from R-SiO₂. 3 / 2 The siloxane unit (T unit) represents an organic group containing an epoxy group.

[0095] The amount of epoxy-containing organic groups in the total silicon atoms bonded to the organic groups in the epoxy-containing organopolysiloxane is not particularly limited, but is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, and for example 40 mol% or less, and preferably 30 mol% or less. The amount of epoxy-containing organic groups can be determined by analysis such as Fourier transform infrared spectrophotometry (FT-IR) or nuclear magnetic resonance (NMR).

[0096] In one embodiment of the invention, the amount of alkenyl groups in the total silicon atoms bonded to the organic groups in the epoxy-containing organopolysiloxane is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, and for example 40 mol% or less, and preferably 30 mol% or less.

[0097] The weight-average molecular weight (Mw) of epoxy-containing organopolysiloxanes (H) is not particularly limited, but is in the range of 500 to 5,000.

[0098] The content of the epoxy-containing organopolysiloxane (H) is not particularly limited, but the total mass of the hot-melt silicone composition of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, and the total mass of the hot-melt silicone composition of the present invention can be 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0099] In another embodiment, the hot-melt curable silicone composition of the present invention is characterized by a low content of resinous organopolysiloxanes (excluding MQ resinous organohydrosiloxanes) in component (D). Therefore, in the hot-melt curable silicone composition, the content of resinous organohydrosiloxanes (excluding MQ resinous organohydrosiloxanes) relative to the total mass of the total organopolysiloxane component is 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less. In another embodiment, the content of resinous organohydrosiloxanes (excluding MQ resinous organohydrosiloxanes) in component (D) is 30% by mass or less, preferably 15% by mass or less, and more preferably 5% by mass or less, based on the mass of the total organohydrosiloxanes contained in the hot-melt curable silicone composition. In another ideal embodiment, the hot-melt curable silicone composition of the present invention does not contain resinous organohydrosiloxanes (excluding MQ resinous organohydrosiloxanes).

[0100] In another embodiment, the hot-melt curable silicone composition of the present invention is characterized by a low content of resinous organopolysiloxanes (excluding MQ resinous organohydrosiloxanes) in component (D). Therefore, in the hot-melt curable silicone composition, the content of resinous organohydrosiloxanes (excluding MQ resinous organohydrosiloxanes) relative to the total mass of the total organopolysiloxane component is 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less. In another ideal embodiment, the hot-melt curable silicone composition of the present invention does not contain resinous organohydrosiloxanes (excluding MQ resinous organohydrosiloxanes).

[0101] The hot-melt curable silicone composition of the present invention is characterized by a low content of aryl groups in the organopolysiloxane. Therefore, in the hot-melt curable silicone composition, the amount of aryl groups in the total silicon atoms bonded to the organic groups in the total organopolysiloxane component is 10 mol% or less, and preferably 5 mol% or less.

[0102] The hot-melt curable silicone composition of the present invention may also contain an alkenyl-containing organopolysiloxane having a branched, resinous, and / or three-dimensional network structure (other than MQ resinous material), provided that the effects of the present invention are not thereby impaired.

[0103] (E) Curing catalyst The curing catalyst of component (E) is a hydrosilylation reaction curing catalyst, which is used to promote the curing of the curable silicone composition of the present invention. Examples of component (E) include platinum-based catalysts, such as chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum-olefin complexes, platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complexes, and platinum-supported powders; palladium-based catalysts, such as tetra(triphenylphosphine)palladium, palladium black, and mixtures thereof; and rhodium-based catalysts; but platinum-based catalysts are particularly preferred.

[0104] The amount of the blended component (E) is a catalytic amount, and more specifically, when a platinum-based catalyst is used as component (E), the amount of platinum atoms relative to the total mass of the curable silicone composition of the present invention is preferably 0.01 ppm or more, more preferably 0.1 ppm or more, and even more preferably 1 ppm or more, and the amount of platinum atoms relative to the total mass of the curable silicone composition of the present invention is preferably 20 ppm or less, more preferably 15 ppm or less, even more preferably 10 ppm or less, and particularly preferably 7 ppm or less.

[0105] (F) Cerium-containing organopolysiloxanes The curable silicone composition of the present invention may contain a cerium-containing polysiloxane as a component (F). The cerium-containing organopolysiloxane (F) can be prepared, for example, by a reaction between a cerium salt of cerium chloride or a carboxylic acid and an alkali metal salt of an organopolysiloxane containing silanol groups. Therefore, as used herein, the term "cerium-containing organopolysiloxane" may refer to a substance obtained by reacting an organopolysiloxane containing silanol groups with a cerium salt, wherein the silanol groups of the organopolysiloxane are chemically bonded to cerium atoms.

[0106] Examples of cerium salts of the aforementioned carboxylic acids include cerium 2-ethylhexanoate, cerium naphthenate, cerium oleate, cerium laurate, and cerium stearate. An example of cerium chloride is cerium trichloride.

[0107] Examples of alkali metal salts of organopolysiloxanes containing silanol groups include potassium salts of organopolysiloxanes with silanol groups at both ends of the molecular chain, sodium salts of organopolysiloxanes with silanol groups at both ends of the molecular chain, potassium salts of organopolysiloxanes with silanol groups at one end of the molecular chain and triorganosiloxy groups at the other end of the molecular chain, and sodium salts of organopolysiloxanes with silanol groups at one end of the molecular chain and triorganosiloxy groups at the other end of the molecular chain. Furthermore, examples of silicon-bonded groups in these organopolysiloxanes include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are replaced by halogen atoms such as fluorine, chlorine, or bromine.

[0108] The above reaction is carried out at room temperature or under heating in the presence of: alcohols such as methanol, ethanol, isopropanol, or butanol; aromatic hydrocarbons such as toluene or xylene; aliphatic hydrocarbons such as hexane or heptane; or organic solvents such as solvent oil, light petroleum, or petroleum ether. The resulting reaction product is preferably treated by distilling off the organic solvent or low-boiling components, or by filtering off the precipitate as needed. Dialkylformamide, hexaalkylphosphamide, etc., may also be added to promote the reaction. The cerium-containing organopolysiloxane thus prepared preferably has a cerium atom content in the range of 0.1 to 15% by mass.

[0109] The content of component (F) is not particularly limited, but preferably is such that the mass fraction of cerium atoms in the total mass of the composition of the present invention is in the range of 0.5 to 100 ppm and more preferably 1 to 50 ppm.

[0110] The content of component (F) is not particularly limited, but is preferably 0.1% by mass or more based on the total mass of the composition of the present invention, and preferably 0.5% by mass or more, and can generally be 3% by mass or less, and preferably 1.5% by mass or less.

[0111] (Other components) Optional components may be blended into the curable silicone compositions of the present invention, provided that the purpose of the invention is not thereby impaired. Examples of optional components include acetylene compounds, organophosphorus compounds, vinyl-containing siloxane compounds; inorganic fillers, such as pulverized quartz, silica, magnesium carbonate, diatomaceous earth, and inorganic fillers obtained by subjecting the surface of such inorganic fillers to a hydrophobic treatment with an organosilicon compound; surface treatment agents, inhibitors of hydrosilylation reactions, tackifiers, agents imparting heat resistance, agents imparting cold resistance, agents imparting flame retardancy, agents imparting thixotropic properties, phosphors, and solvents. Such optional components are typically added in amounts from 0.001 to 20% by mass of the total composition of the present invention.

[0112] Hydrogen silanization reaction inhibitors are components used to inhibit the hydrogen silanization reaction of curable silicone compositions. Examples of such curing reaction inhibitors include alkynols, such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethyn-1-cyclohexanol, and 1-ethynyl-2-cyclohexanol; enynyne compounds, such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; alkenyl-containing low molecular weight siloxanes, such as tetramethyl-tetravinylcyclotetrasiloxane and tetramethyl-tetrahexenylcyclotetrasiloxane; alkynyloxysilanes, such as methyl-tris(1,1-dimethylpropynyloxy)silane, vinyl-tris(1,1-dimethylpropynyloxy)silane, and methyl-tris-(3-methyl-1-butyn-3-oxy)silane; and maleic esters, such as diallyl maleate and bis(2-ethylhexyl) maleate. The inhibitor for the hydrosilylation reaction is preferably selected from alkynols and maleate esters, and particularly preferably includes alkynols and maleate esters. The inhibitor is typically added in an amount of 0.001 to 5% by mass of the total composition of the invention.

[0113] In one embodiment of the invention, the heat-melt curable silicone composition contains at least one type of maleic ester. In one embodiment of the invention, the heat-melt curable silicone composition contains maleic ester in an amount of 0.005% by mass or more, more preferably in an amount of 0.01% by mass or more, and generally in an amount of 1% by mass or less, and preferably 0.5% by mass or less, of maleic ester.

[0114] The hot-melt curable silicone composition according to the invention can be cured to form a cured product with good transparency. For example, the cured product of the curable silicone composition of the invention can exhibit a transmittance of greater than 95% at a wavelength of 450 nm. The transmittance of the cured product of the curable silicone composition can be determined, for example, by measuring the cured product with an optical path length of 1 mm using a spectrophotometer.

[0115] The hot-melt curable silicone composition according to the invention can be cured to form a cured product with high hardness. The cured product obtained by curing the hot-melt curable silicone composition of the invention preferably has a hardness of D20 or greater, as determined by a D-type hardness tester at 25°C. The D-type hardness is determined by means of a D-type hardness tester according to JIS K 6253-1997 “Hardness test method for vulcanized rubber and thermoplastic rubber”.

[0116] The hot-melt curable silicone composition according to the invention can be cured to form a cured product with excellent strength. The cured product obtained by curing the hot-melt curable silicone composition of the invention preferably exhibits a tensile strength at break of 5 MPa or greater and an elongation at break of 50% or greater, as measured at room temperature and a tensile speed of 500 mm / min. Tensile strength (MPa) and elongation at break (%) can be measured using an automatic recorder according to JIS K 6251-1993, “Tensile testing methods for vulcanized rubber”.

[0117] The refractive index of the hot-melt curable silicone composition according to the invention is not particularly limited, but as measured by an Abbe refractometer, the refractive index of the hot-melt curable silicone composition of the invention at 25°C and 589 nm is preferably 1.35 or greater, or 1.45 or less, and even more preferably 1.42 or less.

[0118] The B-stage film of the hot-melt curable silicone composition according to the present invention exhibits good flowability upon heating. The B-stage film of the curable silicone composition of the present invention can have a storage modulus (G') of 5,000 Pa or less when heated at an appropriate temperature. The storage modulus of the B-stage film of the curable silicone composition can be determined, for example, using a rheometer capable of measuring viscoelastic properties.

[0119] The B-stage film of the hot-melt curable silicone composition according to the present invention has a sufficient storage modulus at the operating temperature. For example, the B-stage film of the curable silicone composition of the present invention has a storage modulus (G') of 100,000 Pa or greater at 25°C. The storage modulus of the B-stage film of the curable silicone composition can be determined, for example, using a rheometer capable of measuring viscoelastic properties.

[0120] The curable silicone compositions of the present invention can be prepared by mixing each component. The method for mixing the components can be conventionally known, but is not particularly limited; for example, the compositions can be prepared using a mixing apparatus. Examples of such mixing apparatuses include, but are not particularly limited to, single-screw and twin-screw continuous mixers, twin-roll mixers, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneading mixers, and Henschel mixers.

[0121] [Sealing materials and hot melt adhesives] The present invention also relates to a semiconductor sealing material or hot-melt adhesive using the hot-melt curable silicone composition of the present invention. The shape of the sealing material or hot-melt adhesive of the present invention is not particularly limited, but it is preferably in the form of a film or sheet, and can be provided in the form of a film or laminate for sealing semiconductors. Examples of semiconductors that can be sealed with the sealing material of the present invention include, but are not particularly limited to, semiconductors made of SiC or GaN, particularly power semiconductors or optical semiconductors such as light-emitting diodes.

[0122] [Optical Semiconductor Components] The present invention also relates to an optical semiconductor element provided with the sealing material of the present invention. Examples of optical semiconductor elements include light-emitting diodes (LEDs), semiconductor lasers, photodiodes, phototransistors, solid-state imaging devices, and light emitters and light receivers for optocouplers, wherein light-emitting diodes (LEDs) are particularly preferred.

[0123] Since light is emitted from the top, bottom, left, and right sides of the optical semiconductor element in a light-emitting diode (LED), the components constituting an LED should not be light-absorbing and should be materials with high transmittance or high reflectance. Therefore, the substrate on which the optical semiconductor element is mounted is also a material with high transmittance or high reflectance. Examples of substrates on which the optical semiconductor element is mounted include conductive metals such as silver, gold, and copper; non-conductive metals such as aluminum and nickel; thermoplastic resins mixed with white pigments, such as PPA and LCP; thermosetting resins containing white pigments, such as epoxy resins, BT resins, polyimide resins, and silicone resins; and ceramics such as alumina and aluminum nitride.

[0124] The following presents specific embodiments of the present invention. Example 1: A hot-melt curable silicone composition comprising: (A) an MQ resin containing an alkenyl group of an organopolysiloxane having at least two alkenyl groups per molecule; (B) A straight-chain alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher; (C) Cyclic alkenyl-containing organopolysiloxanes having at least two alkenyl groups per molecule; (D) MQ resin-based organohydrogen polysiloxanes with at least two silicon atoms bonded to hydrogen atoms per molecule; and (E) Curing catalyst, in (i) The content of MQ resin-based organohydrogen polysiloxane (D) is 45% by mass or more relative to the total mass of organohydrogen atoms bonded to silicon atoms; (ii) The amount of aryl groups in the total silicon-bonded organic groups of the total organic polysiloxane component is 10 mol% or less; and (iii) Component (A) accounts for 60% or more of the total mass of components (A) and (B). Example 2: The hot-melt curable silicone composition according to Example 1 further comprises at least one type of maleate. Example 3: A hot-melt curable silicone composition according to Example 1 or 2, wherein the linear alkenyl-containing organopolysiloxane of component (B) comprises 50 or more siloxane units. Example 4: A hot-melt curable silicone composition according to any one of Examples 1 to 3, wherein the mass ratio of component (B) to the total mass of alkenyl-containing organopolysiloxane is preferably 0.5 or less. Example 5: A hot-melt curable silicone composition according to any one of Examples 1 to 4, wherein the mass of component (C) is preferably 0.001 or greater than the total mass of components (A) to (C). Example 6: A hot-melt curable silicone composition according to any one of Examples 1 to 5, further comprising a cerium-containing organopolysiloxane (F). Example 7: A thermosetting curable silicone composition according to any one of Examples 1 to 6, wherein the molar ratio (H / Alk) of hydrogen atoms bonded to silicon atoms to alkenyl groups bonded to silicon atoms in the total organopolysiloxane component is less than 1.2. Example 8: A hot-melt curable silicone composition according to any one of Examples 1 to 7, wherein, based on the total mass of the composition, the content of a linear organohydrogen polysiloxane having 15 or more siloxane units is 2.5% by mass or less. Example 9: A sealing material or hot melt adhesive comprising a hot melt curable silicone composition according to any one of Examples 1 to 8. Example 10: An optical semiconductor device sealed with the sealing material according to Example 9. Example

[0125] The hot-melt curable silicone compositions of the present invention are described in more detail with the aid of the following examples and comparative examples.

[0126] The heat-curable silicone composition is prepared by mixing the respective components in the proportions (parts by weight) shown in the table. Note that in the following text, Me represents methyl, Vi represents vinyl, Ph represents phenyl, and Ep represents 3-glycidoxypropyl. The structures of the organopolysiloxane components are also shown in a simplified manner in the table, and the organic groups in the M, D, T, or Q units (except Me) are shown in parentheses. H / Vi indicates the molar ratio of hydrogen atoms (H) bonded to silicon atoms to vinyl groups (Vi) in the organopolysiloxane component. “Total aryl content” indicates the amount (mol%) of aryl groups in the total organic groups bonded to silicon atoms in the total organopolysiloxane component. (A) / ((A) + (B)) indicates the proportion of the mass of component (A) to the total mass of components (A) and (B).

[0127] Component a-1: Alkenyl-containing MQ resin, composed of an average unit formula (Me3SiO) 1 / 2 ) 37.9 (Me2ViSiO 1 / 2 ) 6.2 (SiO 4 / 2 ) 48.6 (SiO 4 / 2 (OH) 7.2 express Component a-2: Alkenyl-containing MQ resin, composed of an average unit formula (Me3SiO2). 1 / 2 ) 40.9 (Me2ViSiO 1 / 2 ) 6.6 (SiO 4 / 2 (OH) 4.5 (SiO 4 / 2 ) 47.6 express Component a-3: Alkene-containing MQ resin, composed of an average unit formula (Me3SiO) 1 / 2 ) 45 (Me2ViSiO 1 / 2 ) 15 (SiO 4 / 2 ) 40 express Component b-1: A linear alkenyl-containing organopolysiloxane (viscosity at 25°C: 1,000 mPa·s), with the average structural formula Me2ViSiO (Me2SiO). 235 SiMe2Vi indicates Component b-2: A linear alkenyl-containing organopolysiloxane (viscosity at 25°C: 10,000 mPa·s), with the average structural formula Me2ViSiO (Me2SiO). 718 SiMe2Vi indicates Component b-3: A linear alkenyl-containing organopolysiloxane (viscosity at 25°C: 500 mPa·s), with the average structural formula Me2ViSiO (Me2SiO). 195 SiMe2Vi indicates Component b-4: A linear alkenyl-containing organopolysiloxane (viscosity at 25°C: 70 mPa·s), with the average structural formula Me2ViSiO (Me2SiO). 43 SiMe2Vi indicates Component c: Cyclic alkenyl-containing organopolysiloxane, represented by the average structural formula (ViMeSiO)4. Component d: MQ resin, composed of the average unit formula (Me3SiO) 1 / 2 ) 0.2 (HMe2SiO 1 / 2 ) 60 (SiO 4 / 2 ) 39.8 express Component e: A complex of platinum and divinyltetramethyldisiloxane, having a platinum concentration of 3.0% by mass. Component f: Cerium-containing dimethyl polysiloxane (degree of polymerization of the siloxane: approximately 20), having a cerium content of 1.4% by mass. Component g-1: A linear organohydrogen polysiloxane, represented by the average structural formula HMe2SiO(Ph2SiO)SiHMe2. Component g-2: Linear organohydrogen polysiloxane, with the average structural formula HMe2SiO(Me2SiO). 20 SiHMe2 indicates Component g-3: A linear organohydrogen polysiloxane with the average structural formula Me3SiO(HMeSiO). 50 SiMe3 indicates Component g-4: Resinous organohydrogen polysiloxane, composed of an average unit formula (HMe2SiO) 1 / 2 ) 60 (PhSiO 3 / 2 ) 40 express Component h: The condensation product of a methylvinylsiloxane oligomer with silanol-terminated ends and 3-glycidoxypropyltrimethoxysilane (weight average molecular weight (Mw): 1,280; viscosity: 22.5 mm). 2 / s) Component i: bis(2-ethylhexyl) maleate Component j: 1-ethynyl-1-cyclohexanol

[0128] [Evaluate] (Light transmittance) The resulting hot-melt silicone composition was placed between two transparent glass plates and cured by heating at 150°C for 1 hour to prepare a test piece with an optical path length of 1 mm. The transmittance of this test piece at a wavelength of 450 nm was measured at 25°C. OK indicates a transmittance greater than 95%, and NG indicates a transmittance of 95% or less.

[0129] (Hot melt properties) The obtained hot-melt silicone composition was coated onto a release film at a thickness of 0.3 mm and semi-cured in an oven at an appropriate curing temperature and time (5-60 minutes at 100°C-150°C) to obtain a stage B film. OK indicates that the B-stage membrane has a G' of 100,000 Pa or greater and a minimum G' of 5,000 Pa or less.

[0130] (Hardness of the cured product) The obtained hot-melt curable silicone composition was cured at 150°C for 1 hour to prepare 10 mm thick test specimens, and the hardness at 25°C was determined using a D hardness tester. No measurements were taken for comparative examples 1 to 7 because the obtained curable silicone compositions did not exhibit hot-melt properties.

[0131] (Strength and elongation at break of the cured product) The resulting hot-melt silicone composition was applied as a sheet and heated at 150°C for 2 hours to prepare a 1 mm thick cured product in sheet form. As specified in JIS K 6251-1993 “Tensile testing methods for vulcanized rubber,” it was stamped into a No. 3 dumbbell shape, and the tensile strength (MPa) and elongation at break (%) were measured using an automatic recorder manufactured by Shimadzu Corporation at a tensile speed of 500 mm / min. No measurements were performed for Comparative Examples 1 to 7 because the resulting curable silicone compositions did not exhibit hot-melt properties.

[0132] (Refractive index) The refractive index of each obtained thermosetting curable silicone composition at 25°C and 589 nm was determined using an Abbe refractometer. The refractive index of the compositions in all examples and comparative examples was 1.4.

[0133] [Table 1]

[0134] [Table 2]

[0135] [Table 3]

[0136] The following tests were also conducted on the hot melt curable silicone compositions of Examples 1 and 2 above.

[0137] [Evaluate] (Presence of post-heat treatment cracking) Each of the resulting hot-melt curable silicone compositions was cured at 150°C for 1 hour, 10 mm thick test pieces were prepared and kept at 225°C or 270°C for 1,000 hours, and then the cracking of the cured product was visually inspected.

[0138] (Light transmittance after heat treatment) The resulting hot-melt silicone composition was placed between two transparent glass plates and cured by heating at 150°C for 1 hour to prepare a test piece with an optical path length of 1 mm. The test piece was held at 225°C or 270°C for 1,000 hours, and the transmittance at a wavelength of 450 nm was measured at 25°C. OK indicates a transmittance greater than 95%.

[0139] [Table 4]

[0140] As can be seen from the above results, the curable silicone compositions with low aryl content of the present invention exhibit hot-melt properties and can form cured products with excellent transparency and mechanical strength.

[0141] Preferred embodiments of the invention have been described above, but the invention is not limited to these embodiments. Within the scope of the invention, additions, omissions, substitutions, and other modifications can be made to the components. The invention is not limited by the foregoing description, but only by the appended claims.

Claims

1. A hot-melt curable silicone composition comprising: (A) an MQ resin containing an alkenyl group of an organopolysiloxane having at least two alkenyl groups per molecule; (B) A straight-chain alkenyl-containing organopolysiloxane having at least two aryl groups per molecule, wherein the viscosity at 25°C is 300 mPa·s or higher; (C) Cyclic alkenyl-containing organopolysiloxanes having at least two alkenyl groups per molecule; (D) MQ resin-based organohydrogen polysiloxanes with at least two silicon atoms bonded to hydrogen atoms per molecule; and (E) Curing catalyst, in (i) The content of the MQ resin-based organohydrogen polysiloxane (D) is 45% by mass or more relative to the total mass of the organohydrogen polysiloxane having silicon atom bonds; (ii) The amount of aryl groups in the total silicon-bonded organic groups of the total organic polysiloxane component is 10 mol% or less; and (iii) Component (A) accounts for 60% or more of the total mass of components (A) and (B).

2. The hot-melt curable silicone composition of claim 1, further comprising at least one type of maleate ester.

3. The hot-melt curable silicone composition as described in claim 1, wherein, The linear alkenyl-containing organopolysiloxane of component (B) contains 50 or more siloxane units.

4. The hot-melt curable silicone composition as described in claim 1, wherein, The mass ratio of component (B) to the total mass of alkenyl-containing organopolysiloxanes is preferably 0.5 or less.

5. The hot-melt curable silicone composition as described in claim 1, wherein, The mass ratio of component (C) to the total mass of components (A) to (C) is preferably 0.001 or greater.

6. The hot-melt curable silicone composition of claim 1, further comprising a cerium-containing organopolysiloxane (F).

7. The hot-melt curable silicone composition of claim 1, wherein, The molar ratio (H / Alk) of hydrogen atoms bonded to silicon atoms to alkenyl groups bonded to silicon atoms in the total organic polysiloxane component is less than 1.

2.

8. The hot-melt curable silicone composition of claim 1, wherein, Based on the total mass of the composition, the content of linear organohydrogen polysiloxane having 20 or more siloxane units is 2.5% by mass or less.

9. A sealing material or hot melt adhesive comprising a hot melt curable silicone composition as described in any one of claims 1 to 8.

10. An optical semiconductor device sealed with the sealing material as claimed in claim 9.

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