Hot-melt curable silicone composition, sealing material, hot-melt adhesive, and optical semiconductor device

Abstract

To provide a hot-melt curable silicone composition enabling formation of a cured product having superior transparency and mechanical strength with a low aryl group content.SOLUTION: A hot-melt curable silicone composition comprises (A) an MQ resin-like alkenyl group-containing organopolysiloxane containing at least two alkenyl groups in each molecule; (B) a linear alkenyl group-containing organopolysiloxane containing at least two alkenyl groups in each molecule and having a viscosity of 300 mPa s or more at 25°C; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups in each molecule; (D) an MQ resin-like organohydrogenpolysiloxane having at least two silicon atom-bound hydrogen atoms in each molecule; and (E) a curing catalyst.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a hot-melt curable silicone composition, more specifically to a hot-melt curable silicone composition suitable for use as an encapsulant for optical semiconductors. The present invention also relates to an optical semiconductor device encapsulated with an encapsulant made of a cured product of such a hot-melt curable silicone composition. [Background technology]

[0002] Curable silicone compositions are used in a wide range of industrial fields because they cure to form cured products that have excellent heat resistance, cold resistance, electrical insulation, weather resistance, water resistance, and transparency. In particular, the cured products are less likely to discolor than other organic materials, and the deterioration of physical properties such as durability is small, so they are widely used as silicone encapsulants for optical materials, especially for optical semiconductor devices such as light-emitting diodes (LEDs).

[0003] Hot-melt silicones, which are curable, non-fluid at room temperature, can be molded into sheets or films, and become fluid when melted by heating, are used as sealants and hot-melt adhesives for semiconductor devices.

[0004] For example, Patent Document 1 describes a hot-melt silicone which is non-flowable at 25°C and has a melt viscosity of 5,000 Pa s or less at 100°C, and which is obtained by subjecting (A) an alkenyl-containing organopolysiloxane in which 10 mol % or more of all silicon-bonded organic groups are phenyl groups and (B) an organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule {an amount such that the number of silicon-bonded hydrogen atoms in this component is 0.2 to 0.7 moles per mole of alkenyl groups in component (A)} in the presence of (C) a hydrosilylation catalyst {an amount sufficient to promote the hydrosilylation reaction between components (A) and (B)}.

[0005] In addition, Patent Document 2 describes (A) an average unit formula: (R 13 SiO 1 / 2 ) a (R 2 2 SiO 2 / 2 ) b (R 3 SiO 3 / 2 ) c (SiO 4 / 2 ) d (R 4 O 1 / 2 ) e (In the formula, R 1 , R 2 , R 3 are the same or different, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, provided that R 1 40 mol % or less of R 2 30 mol % or more of R 3 are alkenyl groups; R 1 , R 2 , R 3 R is 30 to 60 mol % in total is a phenyl group, 4 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, 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, and c+d is a number from 0.3 to 0.8, and a+b+c+d is 1; (B) 100 parts by mass of an organopolysiloxane represented by the average unit formula: (R 5 3 SiO 1 / 2 ) f (R 5 2 SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (R 6 O 1 / 2 ) j (In the formula, R 5 are the same or different, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, provided that all R 5 10 to 70 mol % of the R5 At least one of R is an alkenyl group; 6 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, 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, and h+i is a number from 0 to 0.2, and f+g+h+i is 1; (C) 0 to 150 parts by mass of an organopolysiloxane represented by the average composition formula: R 7 k H l SiO (4-k-l) / 2 (In the formula, R 7 is a phenyl group or an alkyl group having 1 to 6 carbon atoms, provided that all R 7 wherein 10 to 70 mol % are phenyl groups, 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) {in an amount such that the number of silicon-bonded hydrogen atoms in this component is 0.5 to 2.0 moles per mole of alkenyl groups in components (A) and (B) combined}, and (D) a hydrosilylation reaction catalyst.

[0006] Patent Document 3 also describes (A) an alkenyl-containing organopolysiloxane having at least two alkenyl groups in one molecule, (B) a resin-like organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, in an amount of 0.1 to 5 mass % relative to the total mass of the composition, and (C) a silicone rubber composition having an average unit formula (C-1):(R 1 3 SiO 1 / 2 ) a (R 1 2 SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (In the formula, R 1 are the same or different, an alkyl group, an aryl group, an alkenyl group, an aralkyl group, or an epoxy group-containing organic group, or an alkoxy group, provided that at least one R 1is an alkenyl group, and at least one R 1 is an epoxy group-containing organic group, and a, b, and c are numbers that respectively satisfy 0≦a≦1.0, 0≦b≦1.0, 0≦c<0.9, and a+b+c=1.), (D) a hydrosilylation reaction catalyst, and (E) silica.

[0007] However, conventional hot-melt curable silicone compositions containing a high content of aryl groups have the problem of discoloration and loss of transparency when heated. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] WO2015 / 194158 [Patent Document 2] WO2016 / 035285 [Patent Document 3] Patent Publication No. 2021-21058 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a hot-melt curable silicone composition that has a low aryl group content and is capable of forming a cured product that has excellent transparency and mechanical strength.

[0010] Another object of the present invention is to provide an encapsulant or hot melt adhesive comprising the hot melt curable silicone composition of the present invention. Still another object of the present invention is to provide an optical semiconductor device encapsulated with the encapsulant of the present invention. [Means for solving the problem]

[0011] Means for Solving the Problems The present inventors conducted intensive research to find a solution to the above problems, and as a result, discovered that a curable organopolysiloxane composition comprising at least components (A) to (E) of the present invention and satisfying the following conditions (i) to (iii) is capable of forming a cured product that exhibits hot melt properties and has excellent transparency and mechanical strength, thereby completing the present invention.

[0012] Thus, the present invention provides (A) an MQ resinous alkenyl-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 at 25°C of 300 mPa·s or more; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (D) an MQ resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and (E) Curing catalyst A hot melt curable silicone composition comprising: (i) (D) the content of the MQ resin-like organohydrogenpolysiloxane is 45 mass% or more based on the total mass of the organopolysiloxane having silicon-bonded hydrogen atoms, (ii) the amount of aryl groups in all silicon-bonded organic groups in the entire organopolysiloxane component is 10 mol % or less; (iii) The ratio of the mass of component (A) to the combined mass of components (A) and (B) is 0.6 or greater.

[0013] It is preferred that it further comprises at least one maleic acid ester.

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

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

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

[0017] It is preferred that the composition further contains (F) a cerium-containing organopolysiloxane.

[0018] The molar ratio (H / Ak) of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms contained in the entire organopolysiloxane component is preferably less than 1.2.

[0019] The content of the linear organohydrogenpolysiloxane having 20 or more siloxane units is preferably 2.5 mass % or less based on the total mass of the composition.

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

[0021] The present invention also relates to an optical semiconductor device encapsulated with the encapsulant according to the present invention. Effect of the Invention

[0022] The present invention is capable of providing a hot-melt curable silicone composition that has a low aryl group content and is capable of forming a cured product that has excellent transparency and mechanical strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] [Hot-melt curable silicone composition] The hot-melt curable silicone composition according to the present invention comprises: (A) an MQ resinous alkenyl-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 at 25°C of 300 mPa·s or more; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (D) an MQ resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and (E) Curing catalyst At least (i) (D) the content of the MQ resin-like organohydrogenpolysiloxane is 45 mass% or more based on the total mass of the organopolysiloxane having silicon-bonded hydrogen atoms, (ii) the amount of aryl groups in all silicon-bonded organic groups in the entire organopolysiloxane component is 10 mol % or less; (iii) The hot-melt curable silicone composition relates to a composition in which the proportion of component (A) relative to the combined mass of components (A) and (B) is 60 mass % or greater.

[0024] Each component of the hot-melt curable silicone composition of the present invention will now be described in detail.

[0025] (A) an MQ resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups per molecule; Component (A) is an MQ resin-like alkenyl-containing organopolysiloxane having at least two alkenyl groups in one molecule. The hot-melt curable silicone composition according to the present invention may contain one type of (A) alkenyl-containing MQ resin, or may contain two or more types of (A) alkenyl-containing MQ resins. In this specification, MQ resin-like refers to 3 -SiO 1 / 2 Siloxane units (M units) represented by the formula: and SiO 4 / 2It means an organopolysiloxane consisting only of siloxane units (Q units) represented by the following formula: In this specification, R in the siloxane unit represents a silicon-bonded organic group, for example, a monovalent hydrocarbon group.

[0026] Examples of the alkenyl group contained in component (A) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, and dodecenyl groups, with vinyl groups being preferred.

[0027] Examples of groups bonded to silicon atoms other than alkenyl groups contained in component (A) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, such as alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. The silicon atoms in component (A) may contain small amounts of hydroxyl groups or alkoxy groups, such as methoxy and ethoxy groups, as long as the object of the present invention is not impaired. Groups bonded to silicon atoms in component (A) other than alkenyl groups are preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups. In one embodiment, component (A) does not contain an epoxy group-containing organic group.

[0028] In a preferred embodiment of the present invention, the MQ resinous organohydrogenpolysiloxane of component (A) can be preferably represented by the following average unit formula (I): Average unit formula (I):(R 1 3 SiO 1 / 2 ) s (SiO4 / 2 ) t (XO 1 / 2 ) u In the formula, R 1 is the same or different halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that in one molecule, at least two R 1 is an alkenyl group, 0 < s < 1, 0 < t < 1, 0 ≦ u < 0.4 and s + t + u = 1. u represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1). Also, in the present specification, a chemical formula containing a siloxane unit represented by (SiO x / 2 )(where x is an integer from 1 to 4) is referred to as a "unit formula", and the "structural formula" refers to a chemical formula that does not contain such a siloxane unit.

[0029] As the halogen-substituted or unsubstituted monovalent hydrocarbon group of R 1 in the above formula (I), there are alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group, phenylpropyl group; alkenyl groups having 2 to 12 carbon atoms such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom. R 1 is preferably selected from an alkyl group having 1 to 6 carbon atoms, particularly a methyl group, and an alkenyl group having 2 to 6 carbon atoms, particularly a vinyl group.

[0030] X in the above formula (I) is a hydrogen atom or an alkyl group. As the alkyl group of X, an alkyl group having 1 to 3 carbon atoms is preferable, and specifically, methyl group, ethyl group, and propyl group are exemplified.

[0031] In formula (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 formula (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 formula (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 alkenyl group content of the silicon-bonded organic groups in the MQ resin-like organohydrogenpolysiloxane of component (A) is not particularly limited, but may be, for example, 1 mol% or more, preferably 2 mol% or more, more preferably 3 mol% or more of the total silicon-bonded organic groups, and 30 mol% or less, preferably 20 mol%, more preferably 10 mol% or less of the total silicon-bonded organic groups. The alkenyl group content can be determined, for example, by an analytical method such as a Fourier transform infrared spectrophotometer (FT-IR) or nuclear magnetic resonance (NMR), or by the titration method described below. In this specification, the upper and lower limits of the numerical ranges can be arbitrarily combined to set the numerical range.

[0033] This section explains how to quantify the amount of alkenyl groups in each component by titration. The alkenyl group content in organopolysiloxane components can be accurately quantified by a titration method commonly known as the Wyss method. The principle is as follows. First, alkenyl groups in the organopolysiloxane raw material are subjected to an addition reaction with iodine monochloride as shown in formula (1). Next, excess iodine monochloride is reacted with potassium iodide and liberated as iodine by the reaction shown in formula (2). The liberated iodine is then titrated with a sodium thiosulfate solution. Formula (1)CH 2 =CH- + 2ICl → CH 2 I-CHCl- + ICl (excess) Equation (2) ICl + KI → I 2+ KCl The amount of alkenyl groups in the component can be quantified from the difference between the amount of sodium thiosulfate required for titration and the amount of a separately prepared blank solution.

[0034] In one embodiment of the present invention, the MQ resin-like organohydrogenpolysiloxane of component (A) is characterized by a low content of aryl groups. For example, the content of aryl groups in component (A) (mol % of aryl groups in all silicon-bonded organic groups) may be 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 content of aryl groups can be determined by analysis such as Fourier transform infrared spectrophotometer (FT-IR) and nuclear magnetic resonance (NMR).

[0035] The mass average molecular weight of the MQ resin-like organohydrogenpolysiloxane of the component (A) is not particularly limited, but is, for example, within the range of 1,000 to 100,000. In this specification, the mass average molecular weight can be measured by GPC.

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

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

[0038] The alkenyl groups and non-alkenyl groups bonded to silicon atoms that are contained in component (B) are the same as those described above for component (A), and the same description as for component (A) can be applied.

[0039] The linear alkenyl group-containing organopolysiloxane of component (B) has a viscosity of 300 mPa·s or more at 25°C. More preferably, the linear alkenyl group-containing organopolysiloxane of component (B) has a viscosity of 500 mPa·s or more at 25°C, and even more preferably 800 mPa·s or more. There is no particular upper limit to the viscosity of the linear alkenyl group-containing organopolysiloxane of component (B) at 25°C, but it is usually 100,000 mPa·s or less, and preferably 70,000 mPa·s or less. In this specification, the viscosity of the organopolysiloxane component can be measured at 25°C using a rotational viscometer in accordance with JIS K7117-1.

[0040] In a preferred embodiment, the linear alkenyl group-containing organopolysiloxane of component (B) contains 50 or more siloxane units. In a preferred embodiment, the linear alkenyl group-containing organopolysiloxane of component (B) contains 75 to 1000 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 be preferably represented by the following average structural formula (II-a). Average structural formula (II-a):R1 3 SiO(R 1 SiO 2 / 2 ) n SiR 1 3 (In formula (II-a), R 1 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 1 is an alkenyl group, and n is a number such that the viscosity at 25° C. is 300 mPa·s or more, for example, 50 to 1000.

[0042] In the above formula (II-a), R 1 The alkenyl group and the halogen-substituted or unsubstituted monovalent hydrocarbon group may be the same as those in formula (I) above.

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

[0044] In a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (B) may be a linear organopolysiloxane capped with alkenyl groups at both molecular chain terminals, that is, containing alkenyl groups at both molecular chain terminals. The linear organopolysiloxane of component (B) has a molecular chain side chain (i.e., R 2 -SiO 2 / 2 The siloxane units (D units) represented by the following formula (I) may or may not contain an alkenyl group, but preferably do not contain an alkenyl group.

[0045] Therefore, in a preferred embodiment of the present invention, the linear alkenyl group-containing organopolysiloxane of component (B) can preferably be represented by the following average structural formula (II-b). Average structural formula (II-b):R 1 3 SiO(R 2 2 SiO 2 / 2 ) n SiR 1 3 (In formula (II-b), R 1 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 1 is an alkenyl group, R 2 is an alkyl group, and n is a number such that the viscosity at 25° C. is 300 mPa·s or more, for example, 50 to 1000.

[0046] In the above formula (II-b), R 1 Examples of the alkenyl group include alkenyl groups having 2 to 12 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, and a dodecenyl group, and preferably a vinyl group.

[0047] In the above formula (II-b), R 2 The alkyl group is not particularly limited, and examples thereof include alkyl groups having 1 to 12 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group, and is preferably a methyl group.

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

[0049] The content of alkenyl groups in the linear organopolysiloxane of component (B) (the mole % of alkenyl groups relative to all silicon-bonded organic groups) can be designed as desired, but is usually from 0.1 mol % to 1 mol %.

[0050] In one embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (B) is characterized by a low content of aryl groups.For example, the content of aryl groups in component (B) (mol % of aryl groups in the total silicon-bonded organic groups) can be 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, based on the total mass of the hot-melt curable silicone composition of the present invention. Also, the content of component (B) is preferably 40% by mass or less, more preferably 35% by mass or less, based on the total mass of the hot-melt curable silicone composition of the present invention.

[0052] In the present invention, (iii) the ratio of component (A) to the total mass of components (A) and (B) is 60 mass% or more. Also, the ratio of component (A) to the total mass of components (A) and (B) is usually less than 100 mass%, preferably less than 90 mass%, more preferably 80 mass% or less, and even more preferably 70 mass% or less.

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

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

[0055] As the alkenyl group and the non-alkenyl group bonded to a silicon atom that are contained in component (C), the same groups as those for component (A) can be used.

[0056] The cyclic alkenyl group-containing organopolysiloxane of component (C) is preferably Average structural formula (III):(R 1 2 SiO) n (In formula (III), R 1 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 1 is an alkenyl group, and n is 4 to 20.

[0057] In the above formula (III), R 1 The halogen-substituted or unsubstituted monovalent hydrocarbon group is R 1 The same can be applied.

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

[0059] The content of alkenyl groups in all of the silicon-bonded organic groups in the cyclic alkenyl-group-containing organopolysiloxane of component (C) can be designed as desired, but is usually at least 20 mol %, preferably at least 30 mol %, and more preferably at least 40 mol %, and can be no more than 80 mol %, preferably no more than 70 mol %, and more preferably no more than 60 mol %.

[0060] In one embodiment of the present invention, the cyclic alkenyl group-containing organopolysiloxane of component (C) is characterized by a low content of aryl groups.For example, the content of aryl groups in component (C) (mol % of aryl groups in all silicon-bonded functional groups) may be 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] There are no particular limitations on the content of the cyclic alkenyl group-containing organopolysiloxane of component (C), but it is, for example, based on the total mass of the hot-melt silicone composition of the present invention, at least 0.05 mass%, more preferably at least 0.1 mass%, and typically no more than 10 mass%, preferably no more than 5 mass%, and more preferably no more than 3 mass%.

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

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

[0064] (D) MQ resin-like organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule. Component (D) is an MQ resin-like organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in each molecule. The hot-melt curable silicone composition according to the present invention may contain one type of MQ resin-like organohydrogenpolysiloxane as component (D), or may contain two or more types of MQ resin-like organohydrogenpolysiloxane as component (D).

[0065] (D) component, as the group bonded to the silicon atom other than the silicon atom-bonded hydrogen atom, includes halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups. For example, alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group, phenylpropyl group; groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom are exemplified. Note that the silicon atoms in the (D) component may have a small amount of hydroxyl groups, alkoxy groups such as methoxy group and ethoxy group within the range not impairing the object of the present invention. The group bonded to the silicon atom other than the silicon atom-bonded hydrogen atom in the (D) component is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl group.

[0066] In a preferred embodiment of the present invention, the MQ resin-like organohydrogenpolysiloxane of the (D) component can preferably be represented by the following average unit formula (IV). Average unit formula (IV): (R 4 3 SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 4 is a hydrogen atom or a halogen-substituted or unsubstituted monovalent hydrocarbon group other than the same or different alkenyl groups. However, in one molecule, at least two R 4 are hydrogen atoms, and 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4 and s + t + u = 1. u represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1).

[0067] In the above formula (IV), R4 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group other than the alkenyl group of R include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. 4 R may contain a small amount of hydroxyl groups or alkoxy groups such as methoxy groups and ethoxy groups, as long as the object of the present invention is not impaired. 4 is preferably an alkyl group having 1 to 6 carbon atoms, in particular a methyl group.

[0068] In the above formula (IV), X is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0069] In formula (IV), 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 formula (IV), 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 formula (IV), 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] There are no particular limitations on the mass average molecular weight of the MQ resin-like organohydrogenpolysiloxane of component (D), but it is, for example, within the range of 1,000 to 100,000.

[0071] In one embodiment of the present invention, the MQ resin-like organohydrogenpolysiloxane of component (D) is characterized by a low content of aryl groups. For example, the content of aryl groups in component (D) (mol % of aryl groups in all silicon-bonded organic groups) is 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 mass% or more, more preferably 2 mass% or more, and even more preferably 3 mass% or more, based on the total mass of the hot-melt curable silicone composition of the present invention. Also, the content of component (D) is preferably 30 mass% or less, more preferably 20 mass% or less, and even more preferably 10 mass% or less, based on the total mass of the hot-melt curable silicone composition.

[0073] The content of the MQ resin-like organohydrogenpolysiloxane of component (D) is at least 45 mass % based on the total mass of all organohydrogenpolysiloxanes contained in the hot-melt curable silicone composition, and preferably at least 50 mass %.

[0074] In a preferred embodiment of the present invention, the ratio (H / Ak) of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms contained in the entire organopolysiloxane component of the hot-melt curable silicone composition is an amount such that there are less than 1.2 moles of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups. In other words, the molar ratio (H / Ak) of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms contained in the organopolysiloxane component is less than 1.2, and is usually 0.5 or more, preferably 0.7 or more, and more preferably 0.8 or more.

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

[0076] Examples of the molecular structure of component (G) include linear, partially branched linear, branched, resinous, cyclic, and three-dimensional network structures. Component (G) may be one organohydrogenpolysiloxane having these molecular structures, or a mixture of two or more organohydrogenpolysiloxanes having these molecular structures. Preferably, the hot-melt curable silicone composition of the present invention contains a linear organohydrogenpolysiloxane as component (G). Component (G) is not MQ resinous. In this specification, resinous means having a branched or three-dimensional network structure in the molecular structure. In one embodiment, resinous means that the ratio of R-SiO to all siloxane units in one molecule is 1. 3 / 2 Siloxane units (T units) represented by the formula: and SiO 4 / 2 This refers to organopolysiloxanes in which the proportion of siloxane units (Q units) represented by the following formula is 10% or more. Linear structures that are partially branched are not included in the resin-like structure.

[0077] The groups bonded to silicon atoms other than silicon-bonded hydrogen atoms contained in component (G) can be explained in the same manner as the groups bonded to silicon atoms other than silicon-bonded hydrogen atoms in component (D) described above.

[0078] In one embodiment of the present invention, component (G) includes a linear organohydrogenpolysiloxane, and preferably, the linear organohydrogenpolysiloxane of component (G) can be represented by the following average structural formula (V): Average unit formula(V):R 4 3 SiO(R 4 2 SiO 2 / 2 ) n SiR 4 3 In formula (V), R 4 are hydrogen atoms or the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, provided that at least two R 4 is a hydrogen atom, and n is 1 to 100.

[0079] R in the above formula (V) 4 As the monovalent hydrocarbon group other than the halogen-substituted or unsubstituted alkenyl group and X, R 4 and the same applies as for X.

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

[0081] In a specific embodiment of the present invention, the hot-melt curable silicone composition of the present invention is characterized by a low content of long-chain linear organohydrogenpolysiloxane.In this embodiment, for example, the content of linear organohydrogenpolysiloxane having n of 20 or more in formula (IV) or having 20 or more siloxane units can be 10% by mass or less, more preferably 5% by mass or less, even more preferably 2.5% by mass or less, particularly 1% by mass or less, based on the total mass of the composition.In addition, in another specific embodiment, the hot-melt curable silicone composition of the present invention does not contain linear organohydrogenpolysiloxane having n of 20 or more in formula (IV) or having 20 or more siloxane units.

[0082] In a preferred embodiment of the present invention, the linear organohydrogenpolysiloxane of component (G) contains silicon-bonded hydrogen atoms at both molecular chain terminals. The linear organohydrogenpolysiloxane of component (G) has silicon-bonded hydrogen atoms in the M units, and the D units may or may not contain silicon-bonded hydrogen atoms, but preferably do not.

[0083] The linear organohydrogenpolysiloxane of component (G) preferably contains silicon-bonded aryl groups in the molecular chain side chains. The linear organopolysiloxane of component (G) may or may not contain aryl groups at the molecular chain terminals, but preferably does not. In a preferred embodiment, the linear organohydrogenpolysiloxane of component (G) contains Ar 2 SiO 2 / 2 (wherein Ar represents an aryl group), in which one silicon atom is substituted with two aryl groups.

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

[0085] There are no particular limitations on the amount of component (G), but it is preferably contained in an amount of at least 1 mass %, more preferably at least 2 mass %, and preferably no more than 15 mass %, more preferably no more than 10 mass %, and even more preferably no more than 5 mass %, based on the total mass of the hot-melt curable silicone composition of the present invention.

[0086] (H) Epoxy group-containing organopolysiloxane The hot-melt curable silicone composition according to the present invention may contain an epoxy group-containing organopolysiloxane as an additive, as another organopolysiloxane. (H) The epoxy group-containing organopolysiloxane may preferably be a tackifier. The epoxy group-containing organopolysiloxane differs from components (A) to (D) and (G) in that at least the silicon-bonded organic groups contain an epoxy group-containing organic group.

[0087] The molecular structure of the epoxy group-containing organopolysiloxane may be, for example, a linear structure, a linear structure having some branches, a branched structure, a resin-like structure, a cyclic structure, or a three-dimensional network structure, and preferably a resin-like epoxy group-containing organopolysiloxane. The curable silicone composition according to the present invention may contain one type of epoxy group-containing organopolysiloxane, or may contain a combination of two or more types of epoxy group-containing organopolysiloxanes.

[0088] The epoxy group-containing organopolysiloxane preferably contains, as the alkenyl group, an alkenyl group having 2 to 12 carbon atoms, such as a vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, or dodecenyl group, preferably a vinyl group, and, as the epoxy group-containing organic group, for example, a glycidoxyalkyl group such as a 2-glycidoxyethyl group, a 3-glycidoxypropyl group, or a 4-glycidoxybutyl group; an epoxycycloalkylalkyl group such as a 2-(3,4-epoxycyclohexyl)-ethyl group or a 3-(3,4-epoxycyclohexyl)-propyl group; or an epoxyalkyl group such as a 3,4-epoxybutyl group or a 7,8-epoxyoctyl group, preferably a glycidoxyalkyl group, and particularly preferably a 3-glycidoxypropyl group.

[0089] Examples of groups bonded to silicon atoms other than alkenyl groups and epoxy group-containing organic groups of the epoxy group-containing organopolysiloxane include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups and epoxy group-containing organic groups. Examples include alkyl groups having 1 to 12 carbon atoms, such as methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, neopentyl groups, hexyl groups, cyclohexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, undecyl groups, and dodecyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups, tolyl groups, xylyl groups, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl groups, phenethyl groups, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. Preferred are alkyl groups having 1 to 12 carbon atoms, and in particular methyl groups.

[0090] The resinous epoxy group-containing organopolysiloxane preferably has the following average unit formula (VI): (R 5 3 SiO 1 / 2 ) f (R 5 2 SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (XO 1 / 2 ) j {In formula (VI), R 5 are each independently a halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that at least one R 5 is an alkenyl group, and at least one R 5 is an epoxy group-containing organic group, 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, and f+g+h+i+j=1.0, h+i>0}.

[0091] In the above formula (VI), R 5The halogen-substituted or unsubstituted monovalent hydrocarbon group includes the above-mentioned alkenyl group, epoxy group-containing organic group, and other monovalent hydrocarbon groups. X in the formula (VI) is a hydrogen atom or an alkyl group. The alkyl group of X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0092] In the above formula (VI), 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 the above formula (VI), 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 the above formula (VI), 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 the above formula (VI), 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 resin-like epoxy group-containing organopolysiloxane (H) is represented by the above formula (VI), in which g and h are greater than 0, i.e., R 2 -SiO 2 / 2 Siloxane units (D units) represented by the formula: 3 / 2 The epoxy group-containing resin-like organopolysiloxane contains siloxane units (T units) represented by the formula: 3 -SiO 1 / 2 The epoxy group-containing resin-like organopolysiloxane may or may not contain a siloxane unit (M unit) represented by the following formula: 4 / 2It may or may not contain siloxane units (Q units) represented by the following formula: In a preferred embodiment, the resin-like epoxy group-containing organopolysiloxane (H) is composed of only D units and T units.

[0094] In a preferred embodiment of the present invention, the epoxy group-containing organopolysiloxane has an epoxy group-containing organic group as a pendant group on a molecular side chain. The epoxy group-containing organopolysiloxane is preferably R-SiO 3 / 2 The siloxane unit (T unit) represented by the following formula has an epoxy group-containing organic group.

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

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

[0097] There are no particular limitations on the mass average molecular weight (Mw) of the epoxy group-containing organopolysiloxane of component (H), but it is within the range of 500 to 5,000, for example.

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

[0099] In another embodiment, the hot melt curable silicone composition of the present invention is characterized by a low content of resin-like organohydrogenpolysiloxanes other than the MQ resin-like organohydrogenpolysiloxane of component (D). Therefore, the hot melt curable silicone composition has a content of resin-like organohydrogenpolysiloxanes other than the MQ resin-like organohydrogenpolysiloxanes relative to the total mass of all organopolysiloxane components of 5 mass% or less, preferably 3 mass% or less, more preferably 1 mass% or less. In another embodiment, the content of resin-like organohydrogenpolysiloxanes other than the MQ resin-like organohydrogenpolysiloxane of component (D) is 30 mass% or less, preferably 15 mass% or less, more preferably 5 mass% or less based on the total mass of all organohydrogenpolysiloxanes contained in the hot melt curable silicone composition. In another preferred embodiment, the hot-melt curable silicone composition of the present invention does not contain any resinous organohydrogenpolysiloxane other than the MQ resinous organohydrogenpolysiloxane.

[0100] In another embodiment, the hot melt curable silicone composition of the present invention is characterized by a low content of resinous organohydrogenpolysiloxanes other than the MQ resinous organohydrogenpolysiloxane of component (D). Therefore, the hot melt curable silicone composition has a content of resinous organohydrogenpolysiloxanes other than the MQ resinous organohydrogenpolysiloxanes relative to the total mass of all organopolysiloxane components of 5 mass% or less, preferably 3 mass% or less, and more preferably 1 mass% or less. In another preferred embodiment, the hot melt curable silicone composition of the present invention does not contain resinous organohydrogenpolysiloxanes other than the MQ resinous organohydrogenpolysiloxane.

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

[0102] Furthermore, the hot-melt curable silicone composition of the present invention can contain alkenyl-containing organopolysiloxanes having a branched, resinous, and / or three-dimensional network structure other than MQ resinous, as long as the effects of the present invention are not impaired.

[0103] (E)Curing catalyst The curing catalyst of component (E) is a curing catalyst for hydrosilylation reaction, and is a catalyst for promoting the curing of the curable silicone composition of the present invention. Examples of such component (E) include platinum-based catalysts such as chloroplatinic acid, alcohol solution of chloroplatinic acid, complex of platinum and olefin, complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and powder carrying platinum; palladium-based catalysts such as tetrakis(triphenylphosphine)palladium, palladium black, and mixture with triphenylphosphine; and rhodium-based catalysts, and particularly, platinum-based catalysts are preferred.

[0104] The amount of component (E) is a catalytic amount; 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 at least 0.01 ppm, more preferably at least 0.1 ppm, and even more preferably at least 1 ppm; and the amount of platinum atoms, relative to the total mass of the curable silicone composition of the present invention, is preferably no more than 20 ppm, more preferably no more than 15 ppm, even more preferably no more than 10 ppm, and particularly preferably no more than 7 ppm.

[0105] (F) Cerium-containing organopolysiloxane The curable silicone composition according to the present invention may contain a cerium-containing organopolysiloxane as component (F). The cerium-containing organopolysiloxane (F) can be prepared, for example, by reacting cerium chloride or a cerium salt of a carboxylic acid with an alkali metal salt of a silanol group-containing organopolysiloxane. Therefore, in this specification, the term "cerium-containing organopolysiloxane" can mean a compound obtained by reacting a silanol group-containing organopolysiloxane with a cerium salt, in which the silanol group of the organopolysiloxane is chemically bonded to a cerium atom.

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

[0107] Examples of the alkali metal salt of the silanol group-containing organopolysiloxane include potassium salts of diorganopolysiloxanes having both molecular chain ends blocked with silanol groups, sodium salts of diorganopolysiloxanes having both molecular chain ends blocked with silanol groups, potassium salts of diorganopolysiloxanes having one molecular chain end blocked with a silanol group and the other molecular chain end blocked with a triorganosiloxy group, and sodium salts of diorganopolysiloxanes having one molecular chain end blocked with a silanol group and the other molecular chain end blocked with a triorganosiloxy group. Examples of groups bonded to silicon atoms in this organopolysiloxane include alkyl groups having 1 to 12 carbon atoms, such as methyl groups, ethyl groups, propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, neopentyl groups, hexyl groups, cyclohexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, undecyl groups, and dodecyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups, tolyl groups, xylyl groups, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl groups, phenethyl groups, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine atoms, chlorine atoms, and bromine atoms.

[0108] The above reaction is carried out at room temperature or by heating in an organic solvent such as alcohols such as methanol, ethanol, isopropanol, and butanol; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane and heptane; mineral split, ligroin, and petroleum ether. It is also preferable to distill off the organic solvent or low boiling point components from the resulting reaction product, or to filter the precipitate, as necessary. In order to promote this reaction, dialkylformamide, hexaalkylphosphoamide, and the like may be added. The content of cerium atoms in the cerium-containing organopolysiloxane thus prepared is preferably within the range of 0.1 to 15% by mass.

[0109] The content of component (F) is not particularly limited, but is preferably an amount such that the cerium atoms are within a range of 0.5 to 100 ppm by mass, and more preferably an amount within a range of 1 to 50 ppm, of the total mass of the composition.

[0110] In addition, the content of the (F) component is not particularly limited, but is preferably 0.1 mass% or more, preferably 0.5 mass% or more, and usually 3 mass% or less, preferably 1.5 mass% or less, based on the total mass of the composition.

[0111] (Other ingredients) The curable silicone composition of the present invention can be blended with optional components within a range that does not impair the object of the present invention. Examples of the optional components include acetylene compounds, organic phosphorus compounds, vinyl group-containing siloxane compounds, inorganic fillers, such as inorganic fillers such as crushed quartz, silica, magnesium carbonate, diatomaceous earth, inorganic fillers obtained by hydrophobizing the surface of such inorganic fillers with organic silicon compounds, surface treatment agents, hydrosilylation reaction inhibitors, tackifiers, heat resistance agents, cold resistance agents, flame retardants, thixotropy agents, phosphors, solvents, etc. The amount of such optional components added is usually 0.001 to 20 mass% of the entire composition.

[0112] The hydrosilylation reaction inhibitor is a component that inhibits the hydrosilylation reaction of the curable silicone composition. Examples of such curing reaction inhibitors include alkyne alcohols such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, and 1-ethynyl-2-cyclohexanol; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; alkenyl group-containing low molecular weight siloxanes such as tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane; 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 acid esters such as diallyl maleate and bis(2-ethylhexyl) maleate. The hydrosilylation reaction inhibitor is preferably selected from an alkyne alcohol and a maleic acid ester, and more preferably contains an alkyne alcohol and a maleic acid ester. The amount of the reaction inhibitor added is usually 0.001 to 5% by mass of the entire composition.

[0113] In one embodiment of the present invention, the hot-melt curable silicone composition comprises at least one maleic acid ester. Also, in one embodiment of the present invention, the hot-melt curable silicone composition comprises at least 0.005% by weight of maleic acid ester, more preferably at least 0.01% by weight of maleic acid ester, and typically at most 1% by weight, preferably at most 0.5% by weight of maleic acid ester, based on the total weight of the composition.

[0114] The hot-melt curable silicone composition of the present invention can be cured to form a cured product with good transparency. For example, the cured product of the curable silicone composition of the present invention can show a light transmittance of more than 95% for light with a wavelength of 450 nm. The light 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 using a spectrophotometer.

[0115] The hot-melt curable silicone composition of the present 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 present invention preferably has a type D durometer hardness of D20 or more at 25°C. The type D durometer hardness is determined using a type D durometer in accordance with JIS K 6253-1997 "Testing method for hardness of vulcanized rubber and thermoplastic rubber".

[0116] The hot-melt curable silicone composition of the present invention can be cured to form a cured product with excellent strength. Preferably, the cured product obtained by curing the hot-melt curable silicone composition of the present invention exhibits a tensile strength at break of 5 MPa or more and a tensile elongation at break of 50% or more, measured at room temperature and at a tensile speed of 500 mm / min. The tensile strength (MPa) and elongation (%) at break can be measured using an autograph in accordance with JIS K 6251-1993 "Tensile test method for vulcanized rubber".

[0117] There are no particular limitations on the refractive index of the hot-melt curable silicone composition of the present invention, but for example, the refractive index of the curable silicone composition of the present invention at 25°C and 589 nm, as measured with an Abbe refractometer, is preferably 1.35 or more and 1.45 or less, and more preferably 1.42 or less.

[0118] The B-stage film of the hot-melt curable silicone composition of the present invention can exhibit good fluidity when heated. For example, 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, by a rheometer device having a viscoelasticity measuring function.

[0119] The B-stage film of the hot-melt curable silicone composition according to the present invention has a sufficient storage modulus at working temperature. For example, the B-stage film of the curable silicone composition according to the present invention has a storage modulus (G') of 100,000 Pa or more at 25°C. The storage modulus of the B-stage film of the curable silicone composition can be determined, for example, by a rheometer device having a viscoelasticity measuring function.

[0120] The curable silicone composition of the present invention can be prepared by mixing each component. The method of mixing each component can be a conventionally known method and is not particularly limited, but for example, it can be prepared by mixing using a mixing device. There is no particular limit to such a mixing device, and examples of such a mixing device include a single-screw or double-screw continuous mixer, a double roll, a Ross mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0121] [Sealing materials, hot melt adhesives] The present invention also relates to a semiconductor encapsulant or hot melt adhesive using the hot melt curable silicone composition of the present invention.The shape of the encapsulant or hot melt adhesive of the present invention is not particularly limited, but is preferably in the form of a film or sheet, and can be provided as an encapsulant film or laminate film for semiconductor encapsulation.The semiconductor encapsulated by the encapsulant of the present invention is not particularly limited, and examples thereof include semiconductors such as SiC and GaN, particularly power semiconductors or optical semiconductors such as light-emitting diodes.

[0122] [Optical semiconductor element] The present invention also relates to an optical semiconductor element comprising the encapsulant of the present invention. Examples of the optical semiconductor element include a light emitting diode (LED), a semiconductor laser, a photodiode, a phototransistor, a solid-state image sensor, and a light emitter and a light receiver for a photocoupler, and a light emitting diode (LED) is particularly preferred.

[0123] Since light emitting diodes (LEDs) emit light from the top, bottom, left and right of the optical semiconductor element, it is preferable that the components constituting the light emitting diode (LED) are not light absorbing, and are preferably made of materials with high light transmittance or high reflectance. Therefore, it is preferable that the substrate on which the optical semiconductor element is mounted is also made of materials with high light transmittance or high reflectance. Examples of substrates on which such optical semiconductor elements are 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 alumina nitride.

[0124] Specific embodiments of the present invention will be described below. Aspect 1: (A) an MQ resinous alkenyl-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 at 25°C of 300 mPa·s or more; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (D) an MQ resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and (E) Curing catalyst A hot melt curable silicone composition comprising: (i) (D) the content of the MQ resin-like organohydrogenpolysiloxane is 45 mass% or more based on the total mass of the organopolysiloxane having silicon-bonded hydrogen atoms, (ii) the amount of aryl groups in all silicon-bonded organic groups in the entire organopolysiloxane component is 10 mol % or less; (iii) A hot-melt curable silicone composition, in which the proportion of component (A) relative to the combined mass of components (A) and (B) is 60 mass % or greater. Embodiment 2: The hot-melt curable silicone composition of embodiment 1, further comprising at least one maleic acid ester. Aspect 3: The hot-melt curable silicone composition according to Aspect 1 or 2, wherein the linear alkenyl-containing organopolysiloxane of component (B) contains 50 or more siloxane units. Aspect 4: The hot-melt curable silicone composition according to any one of Aspects 1 to 3, wherein the ratio of the mass of component (B) to the total mass of all alkenyl group-containing organopolysiloxanes is 0.5 or less. Aspect 5: The hot-melt curable silicone composition according to any one of Aspects 1 to 4, wherein the ratio of the mass of component (C) to the total mass of components (A) to (C) is 0.001 or greater. Aspect 6: The hot-melt curable silicone composition according to any one of Aspects 1 to 5, further comprising (F) a cerium-containing organopolysiloxane. Aspect 7: The hot-melt curable silicone composition according to any one of Aspects 1 to 6, wherein the molar ratio (H / Ak) of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms contained in the entire organopolysiloxane component is less than 1.2. Aspect 8: The hot-melt curable silicone composition of any one of Aspects 1 to 7, wherein the content of the linear organohydrogenpolysiloxane having 15 or more siloxane units is 2.5 mass% or less, based on the total mass of the composition. Aspect 9: A sealant or hot melt adhesive comprising the hot melt curable silicone composition according to any one of Aspects 1 to 8. Embodiment 10: An optical semiconductor device encapsulated with the encapsulant of embodiment 9. EXAMPLES

[0125] The hot-melt curable silicone composition of the present invention will be described in more detail below with reference to the following examples and comparative examples.

[0126] The components were mixed in the composition (parts by mass) shown in the table to prepare a hot melt curable silicone composition. In the following, Me represents a methyl group, Vi represents a vinyl group, Ph represents a phenyl group, and Ep represents a 3-glycidoxypropyl group. In addition, the structure of the organopolysiloxane component is shown in a simplified form in the table, and the organic group other than Me in the M, D, T, or Q unit is shown in parentheses. In addition, the H / Vi ratio indicates the molar ratio of silicon-bonded hydrogen atoms (H) to vinyl groups (Vi) in the organopolysiloxane component. In addition, the "total aryl group content" indicates the amount (mol%) of aryl groups in the total silicon-bonded organic groups in the entire organopolysiloxane component. In addition, (A) / ((A)+(B)) indicates the ratio of the mass of the (A) component to the total mass of the (A) component and the (B) component.

[0127] Component a-1: Average unit formula (Me 3 SiO 1 / 2 ) 37.9 (Me 2 ViSiO 1 / 2 ) 6.2 (SiO 4 / 2 ) 48.6 (SiO 4 / 2 )(OH) 7.2 Alkenyl group-containing MQ resin represented by the formula: Component a-2: Average unit formula (Me 3 SiO 1 / 2 ) 40.9 (Me 2 ViSiO 1 / 2 ) 6.6 (SiO 4 / 2 )(OH) 4.5 (SiO 4 / 2 ) 47.6 Alkenyl group-containing MQ resin represented by the formula: Component a-3: Average unit formula (Me 3 SiO 1 / 2 ) 45 (Me 2 ViSiO 1 / 2 ) 15 (SiO4 / 2 ) 40 Alkenyl group-containing MQ resin represented by the formula: Component b-1: Average structural formula Me 2 ViSiO(Me 2 SiO) 235 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi (viscosity at 25°C: 1,000 mPa s) Component b-2: Average structural formula Me 2 ViSiO(Me 2 SiO) 718 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi (viscosity at 25°C: 10,000 mPa s) Component b-3: Average structural formula Me 2 ViSiO(Me 2 SiO) 195 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi (viscosity at 25°C: 500 mPa s) Component b-4: Average structural formula Me 2 ViSiO(Me 2 SiO) 43 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi (viscosity at 25°C: 70 mPa s) Component c: Average structural formula (ViMeSiO) 4 The cyclic alkenyl group-containing organopolysiloxane represented by the formula: Component d: Average unit formula (Me 3 SiO 1 / 2 ) 0.2 (HMe 2 SiO 1 / 2 ) 60 (SiO 4 / 2 ) 39.8 MQ resin, represented by Component e: A complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 3.0 mass% Component f: Cerium-containing dimethylpolysiloxane with a cerium content of 1.4% by mass (siloxane polymerization degree: about 20) Component g-1: Average structural formula HMe2 SiO(Ph 2 SiO)SiHMe 2 A linear organohydrogenpolysiloxane represented by the formula: Component g-2: Average structural formula HMe 2 SiO(Me 2 SiO) 20 SiHMe 2 A linear organohydrogenpolysiloxane represented by the formula: Component g-3: Average structural formula Me 3 SiO(HMeSiO) 50 Sim 3 A linear organohydrogenpolysiloxane represented by the formula: Component g-4: Average unit formula (HMe 2 SiO 1 / 2 ) 60 (PhSiO 3 / 2 ) 40 Resin-like organohydrogenpolysiloxane represented by the formula: Component h: A condensation reaction product of a methylvinylsiloxane oligomer in which both ends of the molecule are blocked with silanol groups and 3-glycidoxypropyltrimethoxysilane (mass average molecular weight (Mw): 1280, viscosity: 22.5 mm 2 / s) Component i: Bis(2-ethylhexyl) maleate Component j: 1-ethynyl-1-cyclohexanol

[0128] [evaluation] (light transmittance) The resulting hot-melt silicone composition was placed between two transparent glass plates and cured by heating at 150°C for one hour to produce a test specimen with an optical path length of 1 mm. The light transmittance of this test specimen for light with a wavelength of 450 nm was measured at 25°C. Test specimens with a light transmittance of over 95% were rated as OK, and those with a light transmittance of 95% or less were rated as NG.

[0129] (Hot melt properties) The obtained hot-melt silicone composition is coated onto a release film to a thickness of 0.3 mm, and then semi-cured in an oven at an appropriate curing temperature and time (100-150°C for 5-60 minutes) to obtain a B-stage film. Films with a G' (Pa) of 100,000 or more at B stage and a minimum G' value (Pa) of 5,000 or less were rated as OK.

[0130] (Hardness of the cured product) The resulting hot-melt curable silicone composition was cured at 150° C. for 1 hour, and a 10 mm thick test specimen was prepared and the hardness at 25° C. was measured using a Durometer D hardness tester. Note that for Comparative Examples 1 to 7, the resulting curable silicone composition did not exhibit hot-melt properties, so no measurement was performed.

[0131] (Breaking strength and elongation of the cured product) The obtained hot-melt curable silicone composition was applied to a sheet and heated at 150°C for 2 hours to produce a 1 mm thick sheet cured product. This was punched out into a dumbbell shape No. 3 as specified in JIS K 6251-1993 "Tensile test method for vulcanized rubber", and the tensile strength (MPa) and elongation (%) at break were measured at a pulling speed of 500 mm / min using an autograph manufactured by Shimadzu Corporation. Note that for Comparative Examples 1 to 7, the obtained curable silicone composition did not exhibit hot-melt properties, so measurements were not made.

[0132] (Refractive Index) The refractive index of the resulting hot-melt curable silicone compositions was measured at 25° C. and 589 nm using an Abbe refractometer. The refractive index of all of the compositions in the Examples and Comparative Examples was 1.4.

[0133] [Table 1]

[0134] [Table 2]

[0135] [Table 3]

[0136] The hot-melt curable silicone compositions of Examples 1 and 2 above were further subjected to the following tests.

[0137] [evaluation] (Presence or absence of cracks after heat treatment) The resulting hot-melt curable silicone composition was cured at 150°C for 1 hour, and 10 mm thick test specimens were prepared. These were then held at 225°C or 270°C for 1000 hours, after which the cured product was visually inspected for the presence or absence of cracks.

[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 specimen with an optical path length of 1 mm. This test specimen was held at 225°C or 270°C for 1000 hours, after which the light transmittance for light with a wavelength of 450 nm was measured at 25°C. Test specimens with a light transmittance of over 95% were rated as OK.

[0139] [Table 4]

[0140] As can be seen from the above results, the curable silicone compositions with a low aryl group content according to the present invention exhibited hot melt properties and were able to form cured products with excellent transparency and mechanical strength.

Claims

1. (A) an MQ resinous alkenyl-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 at 25°C of 300 mPa·s or more; (C) a cyclic alkenyl group-containing organopolysiloxane containing at least two alkenyl groups per molecule; (D) an MQ resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and (E) Curing catalyst A hot melt curable silicone composition comprising: (i) the content of the (D) MQ resin-like organohydrogenpolysiloxane is 45 mass% or more, based on the total mass of the organopolysiloxane having silicon-bonded hydrogen atoms; (ii) the amount of aryl groups in all silicon-bonded organic groups in the entire organopolysiloxane component is 10 mol % or less; (iii) A hot-melt curable silicone composition, in which the proportion of component (A) relative to the combined mass of components (A) and (B) is 60 mass% or more.

2. 10. The hot-melt curable silicone composition of claim 1, further comprising at least one maleic acid ester.

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

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

5. 2. The hot-melt curable silicone composition according to claim 1, wherein the ratio of the mass of component (C) to the total mass of components (A) to (C) is 0.001 or more.

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

7. 2. The hot-melt curable silicone composition according to claim 1, wherein the molar ratio of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms (H / Ak) contained in the entire organopolysiloxane component is less than 1.

2.

8. 2. The hot-melt curable silicone composition according to claim 1, wherein the content of the linear organohydrogenpolysiloxane having 20 or more siloxane units is 2.5 mass % or less, based on the total mass of the composition.

9. A sealant or hot melt adhesive comprising the hot melt curable silicone composition according to any one of claims 1 to 8.

10. An optical semiconductor device encapsulated with the encapsulant according to claim 9 .

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