JP7531472B2 - Modified silicone composition and optical semiconductor device - Google Patents

Description

The present invention relates to a modified silicone composition and an optical semiconductor device.

Organopolysiloxanes (hereinafter sometimes referred to as polysiloxanes) have excellent heat resistance, cold resistance, electrical insulation, light resistance, weather resistance, light transparency, gas permeability, and chemical stability, and are used as excellent materials in a wide variety of fields, from the electrical and electronic fields to transportation equipment, office supplies, cosmetics, and the medical field. In particular, addition-curable silicone compositions (hereinafter sometimes referred to as silicone compositions), which have excellent transparency, are used as materials for optical semiconductors such as LEDs.

A high refractive index and gas barrier properties are essential for surface protection of substrates and LED sealing applications. Using phenyl silicone is effective for achieving a high refractive index and gas barrier properties, but it has problems with heat resistance. In addition, when phenyl silicone is used, its rigidity causes low adhesion to the substrate, and the resin easily peels off with slight bending or load. Therefore, coupling agents and isocyanurate derivatives have been used to improve heat resistance and adhesion (Patent Document 1, Patent Document 2). However, when an isocyanurate derivative is added alone, although heat resistance is improved, a bias in crosslink density occurs, so sufficient improvement in adhesion is not observed, and it is necessary to add a coupling agent to impart adhesion, but coupling agents are not preferable because they generate volatile components during thermal curing and cause voids.

In Patent Document 3, in which an organohydrogenpolysiloxane having a SiH bond at the side chain or terminal portion is used in addition to an isocyanurate derivative to increase adhesion, and Patent Document 4, in which an isocyanuric acid skeleton is introduced into the siloxane skeleton, the crosslink density of the cured product is still insufficient, and sufficient adhesion to the substrate is not obtained. In addition, from the standpoint of compatibility, it is difficult to obtain a colorless, transparent, high-refractive index composition with the isocyanuric acid-modified organopolysiloxane of Patent Document 4.

Furthermore, when an organopolysiloxane in which an isocyanuric acid skeleton is introduced into the siloxane skeleton and terminal portions is used (Patent Document 5), the adhesiveness is improved, but since the number of units of the isocyanuric acid skeleton relative to the polymer units is large, the adhesiveness to flexible organic substrates (such as PET) that are easily deformed is insufficient, and the substrate easily peels off when an external force is applied, although sufficient adhesiveness is shown to rigid resins such as PPA resins, and there is a problem that the adhesiveness is not sufficient, and the substrate easily peels off when an external force is applied. Also, with regard to the isocyanuric acid-modified organopolysiloxane of Patent Document 5, it is difficult to obtain a colorless, transparent, high refractive index composition from the standpoint of compatibility.

JP 2012-007126 A JP 2015-183012 A JP 2015-113348 A JP 2011-116745 A JP 2011-099008 A

The present invention was made in consideration of the above problems, and aims to provide a silicone composition that maintains heat resistance, has excellent adhesion to flexible substrates, has sufficient tensile strength and hardness, and gives a transparent cured product.

In order to solve the above problems, the present invention provides a modified silicone composition, comprising:
(A) an isocyanuric acid-modified linear organopolysiloxane having in each molecule one or more isocyanuric acid skeletons and two or more alkenyl groups having 2 to 10 carbon atoms, and having aromatic monovalent hydrocarbon groups bonded to silicon atoms in an amount of 10% or more based on the total number of substituents bonded to silicon atoms;
(B) a branched-chain organopolysiloxane containing either SiO _4/2 units or R ⁵ SiO _3/2 units, or both, and having two or more alkenyl groups bonded to silicon atoms in one molecule (wherein R ⁵ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms);
The present invention provides a modified silicone composition comprising (C) an organohydrogenpolysiloxane having two or more SiH groups in each molecule, and (D) a platinum group metal catalyst.

Such modified silicone compositions maintain heat resistance, have excellent adhesion to flexible substrates, have sufficient tensile strength and hardness, and give transparent cured products.

In addition, in the present invention, it is preferable that the type D hardness of the cured product of the modified silicone composition, measured by the method described in JIS K 6249:2003, is in the range of 45 to 80.

With this level of hardness, the strength is sufficient, the resin does not become rigid, and peeling from the substrate does not occur.

In the present invention, it is also preferable that the refractive index of the cured product of the modified silicone composition at a wavelength of 589 nm, measured by the method described in JIS K 0062, is in the range of 1.45 to 1.60.

With such a refractive index, the anti-reflection effect is excellent, and the optical semiconductor device has excellent functions such as light transmittance.

The present invention also provides an optical semiconductor device that includes a cured product of the modified silicone composition described above.

Such an optical semiconductor device will be highly reliable.

The modified silicone composition of the present invention has excellent heat resistance, excellent adhesion to flexible substrates, and can give a transparent cured product with sufficient tensile strength and hardness.

As mentioned above, there was a need to develop a silicone composition that maintains heat resistance, has excellent adhesion to flexible substrates, has sufficient tensile strength and hardness, and gives a transparent cured product.

As a result of extensive research into the above-mentioned problems, the inventors discovered that the above-mentioned problems could be solved by introducing an isocyanuric acid skeleton into the side chain or terminal portion of an aryl group-containing organopolysiloxane, and thus completed the present invention.

That is, the present invention provides a modified silicone composition,
(A) an isocyanuric acid-modified linear organopolysiloxane having in each molecule one or more isocyanuric acid skeletons and two or more alkenyl groups having 2 to 10 carbon atoms, and having aromatic monovalent hydrocarbon groups bonded to silicon atoms in an amount of 10% or more based on the total number of substituents bonded to silicon atoms;
(B) a branched-chain organopolysiloxane containing either SiO _4/2 units or R ⁵ SiO _3/2 units, or both, and having two or more alkenyl groups bonded to silicon atoms in one molecule (wherein R ⁵ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms);
The modified silicone composition comprises (C) an organohydrogenpolysiloxane having two or more SiH groups in each molecule, and (D) a platinum group metal catalyst.

The present invention is described in detail below, but is not limited to these.

[Modified Silicone Composition]
The modified silicone composition of the present invention contains the following components (A) to (D). In addition to these components, the composition may contain other additives. Each component will be described below.

[(A) Isocyanuric Acid-Modified Linear Organopolysiloxane]
Component (A) in the present invention is an isocyanuric acid-modified linear organopolysiloxane which has one or more isocyanuric acid skeletons and two or more alkenyl groups having 2 to 10 carbon atoms per molecule, and which has 10% or more aromatic monovalent hydrocarbon groups bonded to silicon atoms, based on the total number of substituents bonded to silicon atoms.

（式中、Ｒ^１は独立して炭素数２～１０の置換または非置換のアルキル基、炭素数６～１０のアリール基、または炭素数２～１０のアルケニル基である。Ｒ^２は独立して炭素数２～１０の置換又は非置換のアルキル基、炭素数２～１０のアルケニル基、または式（２）で示される基であり、少なくとも１つは式（２）で示される基である。Ｒ^１、Ｒ^２のうち２個以上は炭素数２～１０のアルケニル基である。ｘ、ｙはそれぞれ０以上の整数であり、かつｘ＋ｙ≧１を満たす数である。）

（式中、ｎは１～１０の整数、Ｒ^３はヒドロシリル化反応可能な不飽和結合を含んでいてもよい炭素数１～１２の炭化水素基、エポキシ基、及び（メタ）アクリル基から選ばれる基である。） The isocyanuric acid-modified linear organopolysiloxane (A) used in the present invention can be represented by the following formula (1).

(In the formula, R ¹ is independently a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms. R ² is independently a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a group represented by formula (2), and at least one of R ^{1 and R 2 is a group represented by formula (2). Two or more of R 1} and R ² are alkenyl groups having 2 to 10 carbon atoms. x and y are each an integer of 0 or more and are numbers that satisfy x+y≧1.)

(In the formula, n is an integer of 1 to 10, and ^R3 is a group selected from a hydrocarbon group having 1 to 12 carbon atoms which may contain an unsaturated bond capable of hydrosilylation, an epoxy group, and a (meth)acrylic group.)

In formula (1), R ¹ is independently a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms. R ² is independently a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a group represented by formula (2), at least one of which is a group represented by formula (2), preferably two or more. Two or more of R ¹ and R ² are alkenyl groups having 2 to 10 carbon atoms, preferably two. x and y are each an integer of 0 or more, and are numbers satisfying x+y≧1, preferably x≧1.

In formula (2), n is an integer of 1 to 10, and preferably an integer of 1 to 5, and ^R3 is a group selected from a hydrocarbon group having 1 to 12 carbon atoms which may contain a hydrosilylation reactive unsaturated bond, an epoxy group, and a (meth)acrylic group, and is preferably an acrylic group.

Examples of the alkenyl group having 2 to 10 carbon atoms contained in component (A) include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups, with vinyl being particularly preferred.

In addition to the above-mentioned alkenyl groups, the groups bonded to the silicon atom of component (A) include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine atoms or cyano groups, such as halogen-substituted alkyl groups such as chloromethyl, chloropropyl, bromoethyl, and trifluoropropyl groups, and epoxy groups such as cyanoethyl and allylglycidyl groups. Of these, the methyl group is preferred.

The amount of aromatic monovalent hydrocarbon groups bonded to silicon atoms is 10% or more, preferably 10% to 80%, more preferably 15% to 70%, and even more preferably 20% to 60% of the total number of substituents bonded to silicon atoms. If the amount of aromatic monovalent hydrocarbon groups is less than the above lower limit, the isocyanuric acid-modified organopolysiloxane may not be compatible. If the amount of aromatic monovalent hydrocarbon groups is equal to or less than the above upper limit, the isocyanuric acid-modified linear organopolysiloxane remains liquid and is easy to handle.

The isocyanuric acid-modified linear organopolysiloxane, component (A) of the present invention, preferably has a weight average molecular weight (Mw) of 300 to 300,000, more preferably 500 to 200,000. If the weight average molecular weight is 300 or more, the composition will cure sufficiently, and if the weight average molecular weight is 300,000 or less, the composition will not become unnecessarily viscous and unable to flow.

In the present invention, the weight average molecular weight (Mw) refers to a weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions using polystyrene as a standard substance.
[Measurement conditions]
Developing solvent: tetrahydrofuran (THF)
Flow rate: 0.6mL/min
Detector: Refractive index detector (RI)
Column: TSK Guard column Super H-L
TSKgel SuperH4000 (6.0mm I.D. x 15cm x 1)
TSKgel SuperH3000 (6.0mm I.D. x 15cm x 1)
TSKgel SuperH2000 (6.0mm I.D. x 15cm x 2)
(Both manufactured by Tosoh Corporation)
Column temperature: 40°C
Sample injection volume: 20 μL (THF solution with a concentration of 0.5% by weight)

The amount of component (A) is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and even more preferably 20 to 70% by mass, based on the total amount of components (A) and (B).

[(B) Branched Organopolysiloxane]
The component (B) in the present invention is a branched organopolysiloxane that contains either SiO4 _/2 units or ^R5SiO3 _/2 units, or both, and has two or more alkenyl groups bonded to silicon atoms per molecule ( ^R5 is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms).

Component (B) has two or more alkenyl groups bonded to silicon atoms per molecule, and the amount of alkenyl groups contained in component (B) is preferably 0.01 to 0.5 mol/100 g, more preferably 0.05 to 0.3 mol/100 g, and even more preferably 0.10 to 0.25 mol/100 g.
If the amount of alkenyl groups bonded to silicon atoms is 0.01 mol/100 g or more, there will be many crosslinks and the composition will harden, whereas if it is 0.5 mol/100 g or less, the crosslink density will not increase too much and there will be no risk of losing toughness.

Furthermore, the amount of hydroxyl groups bonded to silicon atoms in component (B) is preferably 0.001 to 1.0 mol/100 g, more preferably 0.005 to 0.8 mol/100 g, and even more preferably 0.008 to 0.6 mol/100 g.

Furthermore, in component (B), the amount of alkoxy groups bonded to silicon atoms having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, is preferably 1.0 mol/100 g or less, more preferably 0.8 mol/100 g or less, and even more preferably 0.5 mol/100 g or less.
When the amount of alkoxy groups is 1.0 mol/100 g or less, no alcohol gas is generated as a by-product during curing, and no voids remain in the cured product.
In the present invention, the amount of hydroxyl groups and the amount of alkoxy groups bonded to silicon atoms refer to values measured by ¹ H-NMR and ²⁹ Si-NMR.

Furthermore, component (B) is preferably an organopolysiloxane having a resin structure consisting of 0 to 60 mol%, preferably 0 to 50 mol%, SiO _4/2 units (Q units), 0 to 90 mol%, preferably 30 to 80 mol%, R ⁵ SiO _3/2 units (T units), and 0 to 50 mol%, preferably 0 to 30 mol%, (R ⁵ ) ₃ SiO _1/2 units (M units), and the sum of SiO _4/2 units and R ⁵ SiO _3/2 units is preferably 50 mol% or more. In the above formula, ^R5 is independently a substituted or unsubstituted alkyl group having 1 to 10, and preferably 2 to 5, carbon atoms, an aryl group having 6 to 10, and preferably 6 to 8, carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and it is preferable that the substituent ^R5 bonded to the silicon atom of component (B) has at least one phenyl group and at least one of the substituents ^R5 is an alkenyl group having 2 to 10 carbon atoms.

^R5 in the M unit and the T unit is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and specific examples thereof include lower alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl, tolyl, and xylyl groups; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with cyano groups, for example, chloromethyl, cyanoethyl, and 3,3,3-trifluoropropyl groups. Among these, methyl, phenyl, and vinyl groups are preferred.

Examples of materials for obtaining SiO _4/2 units (Q units) include, but are not limited to, sodium silicate, tetraalkoxysilane, and condensation products thereof.

（上記式中、Ｍｅはメチル基を示す。） Examples of materials for obtaining R ⁵ SiO _3/2 units (T units) include, but are not limited to, organosilicon compounds such as organotrichlorosilane and organotrialkoxysilane represented by the following structural formulas, and condensation products thereof.

(In the above formula, Me represents a methyl group.)

（上記式中、Ｍｅはメチル基を示す。） Examples of materials for obtaining the (R ⁵ ) ₃ SiO _1/2 units (M units) include organosilicon compounds such as triorganochlorosilanes, triorganoalkoxysilanes, and hexaorganodisiloxanes represented by the following structural formulas, but are not limited to these.

(In the above formula, Me represents a methyl group.)

[(C) Organohydrogenpolysiloxane]
Component (C) of the present invention is an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, i.e., an organohydrogenpolysiloxane having two or more SiH groups in one molecule, and reacts with components (A) and (B) to act as a crosslinking agent.
The component (C) can be represented by the following average composition formula (3).
R ⁴ _h H _i SiO _(4-h-i)/2 ...(3)

In the average composition formula (3), R ⁴ is the same or different, unsubstituted or substituted, monovalent hydrocarbon group having 1 to 10 carbon atoms, and h and i are positive numbers satisfying 0.7≦h≦2.1, 0.001≦i≦1.0, and 0.8≦h+i≦3.0, and preferably 1.0≦h≦2.0, 0.01≦i≦1.0, and 1.5≦h+i≦2.5.

Examples of ^R4 include saturated aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, and pentyl groups, saturated cyclic hydrocarbon groups such as cyclopentyl and cyclohexyl groups, aryl groups such as phenyl, tolyl, and xylyl groups, and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups, as well as aromatic hydrocarbon groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, halogenated hydrocarbon groups such as trifluoropropyl and chloropropyl groups, and epoxy groups such as allylglycidyl groups. Of these, saturated aliphatic hydrocarbon groups having 1 to 5 carbon atoms such as methyl, ethyl, and propyl groups, and phenyl groups are preferred.

^R4 has at least one aryl group bonded to a silicon atom in each molecule, and preferably 1 to 100. The organohydrogenpolysiloxane of component (C) contains at least two hydrogen atoms (hydrosilyl groups) bonded to silicon atoms, preferably 2 to 200, and more preferably 3 to 100.

The molecular structure of component (C) is not particularly limited, and any molecular structure, such as linear, cyclic, branched, or three-dimensional network (resin-like), can be used as component (C). When component (C) has a linear structure, the hydrosilyl group may be bonded to silicon atoms only at either the molecular chain terminal or the molecular chain side chain, or may be bonded to silicon atoms at both. In addition, organohydrogenpolysiloxanes that have the number of silicon atoms (or degree of polymerization) in one molecule of typically 2 to 200, and preferably 3 to 100, and that are liquid or solid at room temperature (25°C) can be used.

Specific examples of organohydrogenpolysiloxanes represented by the above average composition formula (3) include tris(hydrogendimethylsiloxy)phenylsilane, a methylhydrogensiloxane-diphenylsiloxane copolymer capped at both ends with trimethylsiloxy groups, a methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer capped at both ends with trimethylsiloxy groups, a methylhydrogensiloxane-methylphenylsiloxane-dimethylsiloxane copolymer capped at both ends with trimethylsiloxy groups, a methylhydrogensiloxane-dimethylsiloxane-diphenylsiloxane copolymer capped at both ends with dimethylhydrogensiloxy groups, a methylhydrogensiloxane-dimethylsiloxane-methylphenylsiloxane copolymer capped at both ends with dimethylhydrogensiloxy groups, and a copolymer of ( _CH3 ) _{2HSiO1 /2} units, SiO4 _/2 units, and _{( C6H5} ) _3SiO and copolymers consisting of _1/2 units.

（式中、ｐ、ｒ、ｓはそれぞれ０以上の整数であり、ｑは１以上の整数である。） In addition, organohydrogenpolysiloxanes represented by the following structures can also be used, but are not limited to these.

(In the formula, p, r, and s are each an integer of 0 or more, and q is an integer of 1 or more.)

The amount of component (C) to be added is preferably an amount such that the hydrosilyl groups of component (C) are 0.1 to 4.0 moles per mole of alkenyl groups bonded to silicon atoms in components (A) and (B), more preferably 0.5 to 3.0 moles, and even more preferably 0.8 to 2.0 moles.

If the amount of hydrosilyl groups in component (C) is 0.1 moles or more, the curing reaction of the composition of the present invention proceeds, and a cured product can be obtained, and the crosslink density and mechanical strength of the resulting cured product will be sufficient, and the heat resistance will also be improved. On the other hand, if the amount of hydrosilyl groups in the blend is 4.0 moles or less, a large amount of unreacted hydrosilyl groups will not remain in the cured product, so there will be no change in physical properties over time or a decrease in the heat resistance of the cured product, and furthermore, no foaming due to a dehydrogenation reaction will occur in the cured product.

[(D) Platinum group metal catalyst]
The component (D) in the present invention is a platinum group metal catalyst, and any of the conventionally known catalysts that promote the hydrosilylation reaction of the components (A) and (B) with the component (C) can be used. It is possible. Considering the cost, platinum, platinum black, platinum-based materials such as chloroplatinic acid, for example, H ₂ PtCl ₆ ·pH ₂ O, K ₂ PtCl ₆ , KHPtCl ₆ ·pH ₂ O, K ₂ PtCl ₄ , _{K2PtCl4.pH2O , PtO2.pH2O , PtCl4.pH2O} , _{PtCl2 , H2PtCl4.pH2O} (where p _{is a} positive integer ₎ , etc. Examples of the catalyst include a complex with a hydrocarbon such as an olefin, an alcohol or a vinyl group-containing organopolysiloxane, and a complex having photoactivity such as trimethyl(methylcyclopentadienyl)platinum. However, a combination of two or more types can also be used. The amount of these catalysts to be added may be an amount effective for curing, and is usually 0.1 to 100 parts by weight of platinum group metal based on the total amount of components (A), (B) and (C). A concentration of 500 ppm is preferred, and a concentration in the range of 0.5 to 100 ppm is particularly preferred.

[Other additives]
Other additives include, for example, reinforcing inorganic fillers such as silica, glass fiber, and fumed silica; inorganic white pigments such as titanium dioxide, zinc oxide, zirconium oxide, calcium carbonate, magnesium oxide, aluminum hydroxide, barium carbonate, magnesium silicate, zinc sulfate, and barium sulfate; non-reinforcing inorganic fillers such as calcium silicate, carbon black, cerium fatty acid salts, barium fatty acid salts, cerium alkoxides, and barium alkoxides; silver (Ag), aluminum (Al), aluminum nitride (AlN), boron nitride (BN), silicon dioxide (silica: SiO ₂ ), aluminum oxide (alumina: Al ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), triiron tetroxide (Fe ₃ O ₄ ), lead oxide (PbO ₂ ), tin oxide (SnO ₂ ), cerium oxide (Ce ₂ O _{3 ,} CeO ₂ ), calcium oxide (CaO), and trimanganese tetroxide (Mn ₃ O _{4 )} . ), barium oxide (BaO), and the like. These can be appropriately blended in an amount of preferably 600 parts by mass or less, and more preferably 10 to 400 parts by mass, per 100 parts by mass of the total of the above components (A) to (D).

The modified silicone composition of the present invention can be applied to a substrate of a given application and then cured. As for the curing conditions, the composition can be sufficiently cured at room temperature (25°C), but can also be cured by heating if necessary. When heating, the composition can be cured at a temperature of, for example, 60 to 200°C.

The hardness of the cured product of the composition of the present invention, measured using a durometer type D hardness tester in accordance with JIS K 6249:2003, i.e., the type D hardness of the cured product of the modified silicone composition measured by the method described in JIS K 6249:2003, is preferably in the range of 45 to 80, more preferably 50 to 75, and even more preferably 55 to 70. If the hardness is 45 or more, the strength is sufficient, and if it is 80 or less, the strength is excellent, the resin does not become rigid, and peeling from the substrate does not occur.

The refractive index at a wavelength of 589 nm of the cured product of the modified silicone composition of the present invention, measured by the method described in JIS K 0062, is preferably in the range of 1.45 to 1.60, more preferably 1.47 to 1.60, and even more preferably 1.50 to 1.60. If the refractive index is 1.45 or more, there is an anti-reflection effect, and if it is 1.60 or less, there is an excellent anti-reflection effect and excellent functions as an optical semiconductor device, such as light transmittance.

The modified silicone composition of the present invention can be used for a variety of applications, including, but not limited to, sealing materials, adhesives, electrical insulating materials, laminates, coatings, inks, paints, sealants, resists, composite materials, films, underfill materials, anti-reflective materials, light diffusing materials, and light reflecting materials.

The present invention also provides an optical semiconductor device in which a semiconductor element is encapsulated with the cured product of the modified silicone composition of the present invention described above, i.e., an optical semiconductor device comprising a cured product of the modified silicone composition of the present invention. In such an optical semiconductor device, the cured product of the composition of the present invention has excellent heat resistance, adhesion to flexible substrates, tensile strength, hardness, and transparency, making it a highly reliable and high-quality product.

The present invention will be specifically explained below with examples and comparative examples, but the present invention is not limited to these. Note that parts indicate parts by mass, and the viscosity of each component indicates the absolute viscosity at 25°C measured with a rotational viscometer as described in JIS K 7117-1:1999.

[Synthesis Example 1]
24.6 g of 1,3,5-triallyl isocyanurate (TAIC) and 52.4 g of a terminal SiH compound represented by the following formula (4) were mixed, and 5 ppm of a divinylsiloxane complex of chloroplatinic acid was added in terms of platinum amount to prepare an isocyanuric acid-modified organopolysiloxane (A-1) represented by the following formula (5).

[Synthesis Example 2]
24.6 g of 1,3,5-triallyl isocyanurate (TAIC) and 510 g of a terminal and side chain SiH compound represented by the following formula (6) were mixed, and 5 ppm of a divinylsiloxane complex of chloroplatinic acid was added in terms of platinum amount to prepare an isocyanuric acid-modified organopolysiloxane (A-2) represented by the following formula (7).

[Example 1]
As component (A), 50 parts of the prepared isocyanuric acid-modified organopolysiloxane (A-1),
As component (B), 50 parts of a branched-chain phenylmethylpolysiloxane (Mw=1,500, amount of hydroxyl groups bonded to silicon atoms: 0.1 mol/100 g) consisting of 80 mol % PhSiO _3/2 units and 20 mol % ViMe ₂ SiO _1/2 units,
As component (C), an organohydrogenpolysiloxane (C-1) represented by the following formula (8) is contained in an amount such that the ratio of the total number of hydrogen atoms bonded to silicon atoms in component (C) to the total number of vinyl groups in components (A) and (B) (hereinafter sometimes referred to as the SiH/SiVi ratio) is 1.0.
and 0.1 parts of an octyl alcohol-modified solution of chloroplatinic acid (platinum element content: 1% by mass) as component (D),
The components were added and thoroughly stirred to prepare a modified silicone composition. This composition was molded by heating at 150° C. for 4 hours to form a cured product (120 mm×110 mm×1 mm), and the following physical properties were measured. The results are shown in Table 1.

（式中、ｐ＝１である。）

(Wherein, p=1.)

[Example 2]
As component (A), 50 parts of the prepared isocyanuric acid-modified organopolysiloxane (A-1),
As component (B), 50 parts of a branched-chain phenylmethylpolysiloxane (Mw=1,500, amount of hydroxyl groups bonded to silicon atoms: 0.1 mol/100 g) consisting of 80 mol % PhSiO _3/2 units and 20 mol % ViMe ₂ SiO _1/2 units,
As component (C), an organohydrogenpolysiloxane (C-2) represented by the following formula (9) is contained in an amount such that the ratio of the total number of hydrogen atoms bonded to silicon atoms in component (C) to the total number of vinyl groups in components (A) and (B) (hereinafter sometimes referred to as the SiH/SiVi ratio) is 1.0.
and 0.1 parts of an octyl alcohol-modified solution of chloroplatinic acid (platinum element content: 1% by mass) as component (D),
The components were added and thoroughly stirred to prepare a modified silicone composition. This composition was molded by heating at 150° C. for 4 hours to form a cured product (120 mm×110 mm×1 mm), and the following physical properties were measured. The results are shown in Table 1.

[Example 3]
A modified silicone composition was obtained by preparing a composition in the same manner as in Example 1, except that 50 parts of isocyanuric acid-modified organopolysiloxane (A-2) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 1. This composition was molded by heating at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 1.

[Example 4]
A modified silicone composition was obtained by preparing a composition in the same manner as in Example 2, except that 50 parts of isocyanuric acid-modified organopolysiloxane (A-2) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 2. This composition was molded by heating at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 1.

[Comparative Example 1]
A silicone composition was obtained by preparing a composition in the same manner as in Example 1, except that 50 parts of the linear organopolysiloxane (A-3) represented by the following formula (10) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 1. This composition was heat-molded at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 2]
A silicone composition was obtained by preparing a composition in the same manner as in Example 2, except that 50 parts of the linear organopolysiloxane (A-3) represented by the above formula (10) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 2. This composition was molded by heating at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 3]
A silicone composition was obtained by preparing a composition in the same manner as in Example 2, except that component (B) used in Example 2 was not added. This composition was heat molded at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 4]
As the component (A), 30 parts of the linear organopolysiloxane (A-3) represented by the above formula (10),
As component (B), 50 parts of a branched-chain phenylmethylpolysiloxane (Mw=1,500, amount of hydroxyl groups bonded to silicon atoms: 0.1 mol/100 g) consisting of 80 mol % PhSiO _3/2 units and 20 mol % ViMe ₂ SiO _1/2 units,
as component (C), an organohydrogenpolysiloxane (C-1) represented by the above formula (8) in an amount such that the ratio of the total number of hydrogen atoms bonded to silicon atoms in component (C) to the total number of vinyl groups in components (A), (B), and triallyl isocyanurate (hereinafter sometimes referred to as the SiH/SiVi ratio) is 1.0;
0.1 parts of an octyl alcohol modified solution of chloroplatinic acid (platinum element content: 1 mass%) as component (D) and 20 parts of triallyl isocyanurate were added and thoroughly stirred to prepare a silicone composition. This composition was heated and molded at 150°C for 4 hours to form a cured product (120mm x 110mm x 1mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 5]
As the component (A), 30 parts of the linear organopolysiloxane (A-3) represented by the above formula (10),
As component (B), 50 parts of a branched-chain phenylmethylpolysiloxane (Mw=1,500, amount of hydroxyl groups bonded to silicon atoms: 0.1 mol/100 g) consisting of 80 mol % PhSiO _3/2 units and 20 mol % ViMe ₂ SiO _1/2 units,
as component (C), an organohydrogenpolysiloxane (C-1) represented by the above formula (8) in an amount such that the ratio of the total number of hydrogen atoms bonded to silicon atoms in component (C) to the total number of vinyl groups in components (A), (B), and triallyl isocyanurate (hereinafter sometimes referred to as the SiH/SiVi ratio) is 1.0;
(D) 0.1 parts of an octyl alcohol denatured solution of chloroplatinic acid (platinum element content: 1% by mass),
A silicone composition was prepared by adding 20 parts of triallyl isocyanurate and 5 parts of a coupling agent obtained by mixing 2 parts of γ-methacryloxypropyltrimethoxysilane and 8 parts of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and thoroughly stirring the mixture. This composition was molded by heating at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 6]
As the component (A), 30 parts of the linear organopolysiloxane (A-3) represented by the above formula (10),
As component (B), 50 parts of a branched-chain phenylmethylpolysiloxane (Mw=1,500, amount of hydroxyl groups bonded to silicon atoms: 0.1 mol/100 g) consisting of 80 mol % PhSiO _3/2 units and 20 mol % ViMe ₂ SiO _1/2 units,
As component (C), an organohydrogenpolysiloxane (C-1) represented by the above formula (8), SiH/SiVi=0.5, and an organohydrogenpolysiloxane (C-3) represented by the following formula (11), SiH/SiVi=0.5, are included in an amount such that the ratio of the total number of hydrogen atoms bonded to silicon atoms in component (C) to the total number of vinyl groups in components (A), (B), and triallyl isocyanurate (hereinafter sometimes referred to as SiH/SiVi ratio) is 1.0:
0.1 parts of an octyl alcohol modified solution of chloroplatinic acid (platinum element content: 1 mass%) as component (D) and 20 parts of triallyl isocyanurate were added and thoroughly stirred to prepare a silicone composition. This composition was heated and molded at 150°C for 4 hours to form a cured product (120mm x 110mm x 1mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 7]
A silicone composition was obtained by preparing a composition in the same manner as in Example 1, except that 50 parts of the isocyanuric acid-modified organopolysiloxane (A-4) represented by the following formula (12) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 1. This composition was heat-molded at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

[Comparative Example 8]
A silicone composition was obtained by preparing a composition in the same manner as in Example 1, except that 50 parts of an isocyanuric acid-modified organopolysiloxane (A-5) represented by the following formula (13) was used as component (A) instead of the isocyanuric acid-modified organopolysiloxane (A-1) used in Example 1. This composition was heat-molded at 150°C for 4 hours to form a cured product (120 mm x 110 mm x 1 mm), and the following physical properties were measured. The results are shown in Table 2.

The physical properties of the compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 8, and their cured products, were measured using the methods described below. The results are shown in Tables 1 and 2.

(1) Appearance Each composition was cured at 150° C. for 4 hours, and the color, transparency, and the presence or absence of voids of the resulting cured product (1 mm) were visually inspected.

(2) Properties The fluidity of each composition before curing was confirmed. 50 g of the composition was added to a 100 ml glass bottle, and the glass bottle was turned on its side and left to stand at 25° C. for 10 minutes. If the composition flowed during that time, it was determined to be in a liquid state.

(3) Viscosity The viscosity of each composition before curing at 25° C. was measured by the method described in JIS K 7117-1:1999.

(4) Refractive Index The refractive index of the cured product obtained by curing each composition at 150° C. for 4 hours was measured using an ATAGO digital refractometer RX-9000α at 25° C. by the method described in JIS K 0062 for measuring the refractive index of light with a wavelength of 589 nm.

(5) Hardness (Type D)
Each composition was cured at 150° C. for 4 hours, and the hardness of the cured product was measured using a durometer type D hardness tester in accordance with JIS K 6249:2003.

(6) Elongation at Break and Tensile Strength Each composition was cured at 150° C. for 4 hours, and the elongation at break and tensile strength of the cured product were measured in accordance with JIS K 6249:2003.

(7) Adhesion 0.25 g of each composition was molded onto a copper plate with an area of ¹⁸⁰ mm2 so that the bottom area was 45 ^mm2 , and cured at 150°C for 4 hours to prepare an adhesion test piece. The shear adhesive strength of the test piece was measured at 25°C using a bond tester DAGE-SERIES-4000PXY (manufactured by DAGE Corporation). After the adhesion test, the ratio of the area of cohesive failure to the area of peeling was calculated to evaluate the adhesiveness.
(Judgment criteria)
○: Good adhesion (cohesive failure rate 80% or more)
×: poor adhesion (cohesive failure rate less than 80%)

(8) Thermal Shock Resistance The test pieces used in the above adhesion test were subjected to a thermal shock test of 1,000 cycles at −40° C. to 120° C. using a liquid bath thermal shock tester (manufactured by Espec Corp.). After the test, an adhesion test was performed under the same conditions as above, and the ratio of the area of cohesive failure to the area of peeling was calculated after the adhesion test to evaluate the adhesion.
(Judgment criteria)
○: Good adhesion (cohesive failure rate 80% or more)
×: poor adhesion (cohesive failure rate less than 80%)

(9) Heat Resistance Test The modified silicone composition was cured at 150° C. for 4 hours and then left to stand at 150° C. for 100 hours, after which any change in color was visually confirmed.
(Judgment criteria)
○: No yellowing observed ×: Yellowing observed

(10) Adhesion to Flexible Substrates Each modified silicone composition was applied to the surface of a PET flexible substrate (width 25 mm, thickness 50 μm, length 70 mm) to a thickness of 0.5 mm and cured to form a coating. Force was applied to the substrate to temporarily deform it, and adhesion was evaluated.
(Judgment criteria)
○: No peeling is observed ×: Peeling is observed

As shown in Table 1, the modified silicone compositions of Examples 1 to 4, which used an isocyanuric acid-modified organopolysiloxane containing an aryl group as component (A), gave cured products with sufficient viscosity, appearance, refractive index, hardness, elongation at break, tensile strength, adhesion, fracture mode heat resistance, adhesion to flexible substrates, and transparency. In contrast, Comparative Examples 1 and 2, which used a linear organopolysiloxane that was not modified with isocyanuric acid, had low adhesion and the fracture mode of adhesion was peeling, and after the thermal shock test, the substrate peeled off due to a slight impact during the test. In addition, heat resistance and substrate adhesion were poor. Comparative Example 3, which did not contain the branched organopolysiloxane (component (B)), did not obtain sufficient tensile strength or hardness, and there were problems with strength. In Comparative Example 4, which added triallyl isocyanurate, heat resistance was improved, but adhesion was insufficient and the fracture mode was interfacial peeling. In Comparative Example 5, in which a coupling agent was added, adhesion improved, but voids were observed in the cured product due to the volatile components generated, and the product peeled off easily from the flexible substrate. In Comparative Example 6, in which a terminal organohydrogenpolysiloxane and a side-chain organohydrogenpolysiloxane were used in combination, no sufficient improvement in adhesion was observed. In Comparative Examples 7 and 8, in which an isocyanuric acid-modified organopolysiloxane that does not contain aryl groups was used, the cured product became opaque, and it was not possible to obtain a sufficient refractive index or adhesion to flexible substrates.

As described above, the modified silicone composition of the present invention can give a cured product that has sufficient tensile strength, high hardness, and excellent appearance (transparency), heat resistance, adhesion, and adhesion to flexible substrates.

The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

Claims (4)

A modified silicone composition comprising:
(A) an isocyanuric acid-modified linear organopolysiloxane having in each molecule one or more isocyanuric acid skeletons and two or more alkenyl groups having 2 to 10 carbon atoms, and having aromatic monovalent hydrocarbon groups bonded to silicon atoms in an amount of 10% or more based on the total number of substituents bonded to silicon atoms;
(B) a branched-chain organopolysiloxane containing either SiO _4/2 units or R ⁵ SiO _3/2 units, or both, and having two or more alkenyl groups bonded to silicon atoms in one molecule (wherein R ⁵ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms);
A modified silicone composition comprising: (C) an organohydrogenpolysiloxane having two or more SiH groups in each molecule; and (D) a platinum group metal catalyst. The modified silicone composition according to claim 1, characterized in that the cured product of the modified silicone composition has a type D hardness in the range of 45 to 80, as measured by the method described in JIS K 6249:2003. The modified silicone composition according to claim 1 or 2, characterized in that the refractive index of the cured product of the modified silicone composition at a wavelength of 589 nm, measured by the method described in JIS K 0062, is in the range of 1.45 to 1.60. An optical semiconductor device comprising a cured product of the modified silicone composition according to any one of claims 1 to 3.