Addition-curable silicone composition, cured product thereof, lens, and optical semiconductor device

Abstract

The present invention is an addition-curable silicone composition characterized by containing (A) a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both molecular chain ends, (B) an organopolysiloxane resin having alkenyl groups bonded to silicon atoms, (C) a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, (D) a platinum group metal catalyst, and (E) silica, wherein the refractive index is less than 1.42, the ratio of viscosity at a shear rate of 1 s-1 to viscosity at a shear rate of 10 s-1 is 3.0 or more, and the light transmittance of a cured product obtained by curing the composition is 50% or more. Through this feature, the present invention provides: an addition-curable silicone composition which has thixotropy and is capable of providing a cured product with excellent transparency and heat discoloration resistance when cured; a cured product thereof; a lens made of the cured product; and an optical semiconductor device.

Description

Addition-curing silicone composition, cured product thereof, lens, and optoelectronic device.

[0001] The present invention relates to an addition-curing silicone composition, a cured product thereof, a lens, and an optoelectronic device.

[0002] Dome-shaped encapsulating materials, which offer excellent light diffusion, are widely used as encapsulating materials for light-emitting diode (LED) elements, and these require high heat resistance and transparency.

[0003] A common method for forming a dome-shaped sealing material involves applying a thixotropic curable resin composition onto an LED element using a dispenser, and then curing it while maintaining its shape due to the thixotropic properties of the composition.

[0004] Addition-curing methyl silicone resin is an example of a resin with excellent heat resistance. It has particularly good heat discoloration resistance and adhesive strength, and has the advantage of not degrading in terms of light transmittance and hardness even at high temperatures.

[0005] Furthermore, one method for imparting thixotropy and strength to addition-curing silicone resin compositions is to add nano-sized silica particles to the composition (Patent Documents 1 and 2). However, there is a problem in that the transparency decreases when nano-silica is added to methyl silicone resin. This decrease in transparency is due to the difference in refractive index between the resin and silica. The refractive index of silica is around 1.45, while that of methyl silicone is less than 1.42, causing light scattering and clouding of the cured product.

[0006] In contrast, introducing aryl groups into the silicone skeleton increases the refractive index to 1.42-1.45, improving transparency when mixed with nanosilica. However, this presents a problem: discoloration occurs at high temperatures due to oxidation of the aryl groups.

[0007] Japanese Patent Publication No. 2019-089913 Japanese Patent Publication No. 2020-132739

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide an addition-curable silicone composition capable of giving a cured product having thixotropic properties and excellent transparency and heat discoloration resistance when cured, a cured product thereof, a lens made of the cured product, and an optical semiconductor device.

[0009] In order to solve the above problems, in the present invention, there is provided an addition-curable silicone composition containing: (A) a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain; (B) an organopolysiloxane resin having alkenyl groups bonded to silicon atoms; (C) a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms; (D) a platinum group metal-based catalyst; and (E) silica, having a refractive index of less than 1.42 for the sodium D line at 25°C, and a ratio of the viscosity at a shear rate of 1 s to the viscosity at a shear rate of 10 s at 23°C of 3.0 or more, and an addition-curable silicone composition in which the light transmittance at a wavelength of 400 nm at a thickness of 2 mm of the cured product obtained by curing the addition-curable silicone composition is 50% or more. －１ to the viscosity at a shear rate of －１ 1 s at 23°C is 3.0 or more, and the light transmittance at a wavelength of 400 nm at a thickness of 2 mm of the cured product obtained by curing the addition-curable silicone composition is 50% or more.

[0010] The addition-curable silicone composition of the present invention can provide a cured product that is highly transparent and excellent in heat discoloration resistance after curing, even though it is an addition-curable silicone composition having a refractive index of less than 1.42 and containing silica and having thixotropic properties.

[0011] Further, in the present invention, the component (A) is preferably a linear organopolysiloxane composed of (R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) units (where R １ is independently an alkyl group or an alkenyl group, and R ２ is an alkenyl group), and the amount of alkenyl groups is 0.020 mol / 100 g or more.

[0012] An addition-curing silicone composition containing such component (A) can provide a cured product with particularly excellent transparency and heat discoloration resistance.

[0013] Furthermore, in the present invention, it is preferable that the above-mentioned component (B) is represented by the following general formula (1). (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of the following is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, and g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, and g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.2.

[0014] An addition-curing silicone composition containing such component (B) can provide a cured product with particularly excellent strength and heat resistance to discoloration.

[0015] Furthermore, in the present invention, it is preferable that the amount of alkenyl groups in component (B) is 0.04 mol / 100 g or more.

[0016] An addition-curing silicone composition containing such component (B) will have superior transparency after curing.

[0017] Furthermore, in the present invention, component (C) is (R ５ HSiO ２／２ ) Unit (R ５ It is preferable that the linear alkylhydrogenpolysiloxane has an alkyl group and does not have an aryl group.

[0018] An addition-curing silicone composition containing such a (C) component can yield a cured product with particularly excellent strength and heat resistance / discoloration resistance.

[0019] Furthermore, in the present invention, the above-mentioned component (E) has a BET specific surface area of ​​100 m². ２ It is preferable that the fumed silica is of a concentration of 1 / g or higher.

[0020] With such a (E) component, the addition-curing silicone composition can have appropriate thixotropy and produce a cured product with excellent transparency.

[0021] Furthermore, in the present invention, it is preferable that component (E) is surface-treated with dichlorodimethylsilane or trimethyldisilazane.

[0022] With such a (E) component, it becomes possible to suppress the thickening of the addition-curing silicone composition during storage, resulting in an addition-curing silicone composition with excellent moldability.

[0023] Furthermore, in the present invention, it is preferable that the amount of component (E) is 5 to 20 parts by mass relative to 100 parts by mass of the total of components (A) and (B).

[0024] If the amount of component (E) is within this range, an addition-curing silicone composition with appropriate viscosity and thixotropy will be obtained, and the cured product will have good transparency.

[0025] Furthermore, the present invention relates to an addition-curing silicone composition, wherein (A')(R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １Each of these is independently an alkyl group or an alkenyl group, R ２ (R) is an alkenyl group. (B') A linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, and an organopolysiloxane resin represented by the following general formula (1), and (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of these is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.2. ) (C')(R ５ HSiO ２／２ ) Unit (R ５ (D') a linear alkylhydrogenpolysiloxane having an alkyl group and no aryl group, (E') a platinum group metal catalyst, and (E') a BET specific surface area of ​​100 m ２ The present invention provides an addition-curing silicone composition containing silica of 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B').

[0026] Such an addition-curing silicone composition can provide a cured product that is thixotropic, highly transparent after curing, and has excellent heat resistance and discoloration properties, even if it contains silica.

[0027] In this case, it is preferable that the alkyl group in component (A'), component (B'), and component (C') is a methyl group, and the alkenyl group in component (A') and component (B') is a vinyl group.

[0028] Such addition-curing silicone compositions offer superior strength and heat resistance to discoloration of the cured product.

[0029] Furthermore, the present invention provides a cured product which is a cured product obtained by curing the addition-curing type silicone composition described above.

[0030] Because such cured materials exhibit excellent transparency, they are useful for applications such as encapsulation materials and lens materials for semiconductor devices, especially those used in optical applications.

[0031] In this case, it is preferable that the durometer type A hardness is 70 to 95.

[0032] Such a hardened material offers superior strength.

[0033] Furthermore, the present invention provides a lens made of the cured material described above.

[0034] The cured product of the present invention exhibits excellent transparency and heat resistance to discoloration. Therefore, lenses made from such cured products are highly reliable.

[0035] Furthermore, the present invention provides an optoelectronic device in which an optical element is sealed with the cured material described above.

[0036] The cured product of the present invention exhibits excellent transparency and heat resistance to discoloration. Therefore, an optoelectronic device in which optical elements are sealed with such a cured product is highly reliable.

[0037] As described above, the addition-curing silicone composition of the present invention is an addition-curing silicone composition having a refractive index of less than 1.42. Even when it contains silica as a thixotropic agent, it can provide a cured product that is highly transparent and excellent in heat discoloration resistance after curing, and is useful as an electric and electronic component, particularly as a lens material or an LED encapsulation material.

[0038] As described above, there has been a demand for the development of an addition-curing silicone composition that is an addition-curing silicone composition having a refractive index of less than 1.42 (that is, not containing an aryl group or having a low content of an aryl group in the silicone skeleton), and that can provide a cured product that is highly transparent and excellent in heat discoloration resistance even when it contains silica as a thixotropic agent.

[0039] As a result of intensive studies on the above problems, the present inventor has found that an addition-curing silicone composition containing the components (A) to (E) or the components (A') to (E') described below can solve the above problems, and has completed the present invention.

[0040] That is, the present invention is an addition-curing silicone composition comprising: (A) a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain; (B) an organopolysiloxane resin having alkenyl groups bonded to silicon atoms; (C) a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms; (D) a platinum group metal-based catalyst; and (E) silica, having a refractive index of less than 1.42 for the sodium D line at 25°C, and a ratio of the viscosity at a shear rate of 1 s －１ to the viscosity at a shear rate of 10 s －１ at 23°C of 3.0 or more, and having a light transmittance of 50% or more at a wavelength of 400 nm at a thickness of 2 mm of the cured product obtained by curing the addition-curing silicone composition.

[0041] Further, the present invention is an addition-curing silicone composition comprising: (A') (R １ ２ R ２ SiO １／２ ), units and (R １ ２ SiO２／２ )(R unit １ is, independently of one another, an alkyl group or an alkenyl group, and R ２ is an alkenyl group.) and a linear organopolysiloxane having an alkenyl group content of 0.020 mol / 100 g or more, (B') an organopolysiloxane resin represented by the following general formula (1), (R ３ ３ SiO １／２ )(R ａ (R ４ R ３ ２ SiO １／２ )(R ｂ (R ４ R ３ SiO ２／２ )(R ｃ (R ３ ２ SiO ２／２ )(R ｄ (R ４ SiO ３／２ )(R ｅ (R ３ SiO ３／２ )(SiO ｆ (SiO ４／２ (XO １／２ )(1) (In the formula, R ３ are each independently an alkyl group, R ４ are each independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, g are each such that a≥0, b≥0, c≥0, d≥0, e≥0, f≥0, g≥0, provided that b + c + e>0, e + f + g>0, and a + b + c + d + e + f + g = 1, and h is a number from 0 to 0.2.) (C') a linear alkylhydrogenpolysiloxane having a unit (R ５ HSiO ２／２ )(R ５ is an alkyl group.) and having no aryl group, (D') a platinum group metal-based catalyst, and (E') silica having a BET specific surface area of 100 m ２ / g or more: 5 to 20 parts by mass with respect to a total of 100 parts by mass of the (A') component and the (B') component, and is an addition-curable silicone composition containing the same. ​​​​

[0042] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0043] [Addition-curing silicone composition] A first aspect of the addition-curing silicone composition of the present invention comprises components (A) to (E) described later, wherein the refractive index of the sodium D line at 25°C is less than 1.42, and the shear rate at 23°C is 10 s. －１ Shear rate 1s for viscosity －１ The viscosity ratio is 3.0 or higher, and the light transmittance at a wavelength of 400 nm at a thickness of 2 mm of the cured product obtained by curing the addition-curing silicone composition is 50% or higher. Each component will be described in detail below.

[0044] <Component (A)> Component (A) is a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain, and is a component that undergoes a hydrosilylation reaction with component (C), which will be described later.

[0045] The alkenyl group bonded to the silicon atom is not particularly limited, but an alkenyl group having 2 to 10 carbon atoms is preferred, and an alkenyl group having 2 to 8 carbon atoms is more preferred.

[0046] Specific examples include vinyl groups, allyl groups, 3-butenyl groups, 5-hexenyl groups, and 7-octenyl groups. Among these, vinyl groups are preferred due to their ease of synthesis and cost-effectiveness.

[0047] Alkenyl groups may be present not only at both ends of the organopolysiloxane molecular chain, but also in the middle of the molecular chain; however, for flexibility reasons, it is preferable that they be present only at both ends.

[0048] Organic groups other than alkenyl groups bonded to silicon atoms include alkyl groups, and examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, etc. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance to discoloration of the cured product.

[0049] Therefore, component (A) above is (R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２ A linear organopolysiloxane consisting of (where is an alkenyl group) is preferred.

[0050] R １ Examples of alkyl groups in this context include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0051] R １ and R ２ Examples of alkenyl groups in this compound include vinyl groups, allyl groups, 3-butenyl groups, 5-hexenyl groups, and 7-octenyl groups, with a preference for alkenyl groups having 2 to 8 carbon atoms, and a preference for vinyl groups.

[0052] The amount of alkenyl groups in component (A) above is preferably 0.020 moles or more per 100g, more preferably 0.020 to 0.500 moles, and even more preferably 0.025 to 0.200 moles. When the amount is 0.020 moles / 100g or more, the transparency of the cured product is improved. This is presumed to be because the refractive index is increased by the Si-alkylene structure derived from the alkenyl groups generated after the hydrosilylation reaction, and the refractive index difference with silica is reduced. Furthermore, when the amount of alkenyl groups is 0.500 moles / 100g or less, the occurrence of cracks in the cured product can be suppressed.

[0053] That is, the above (A) component is (R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２ It is preferable that the compound consists of an alkenyl group and has a linear organopolysiloxane with an alkenyl group content of 0.020 mol / 100g or more.

[0054] The viscosity of component (A) at 25°C, as measured by a rotational viscometer, is preferably 5 to 3,000 mPa·s, and more preferably 10 to 2,000 mPa·s. Within this range, the resulting composition tends to have good workability and handling properties, and is less prone to the entrapment of bubbles and air during molding and curing.

[0055] Specific examples of component (A) above include, for example, dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends, dimethylsiloxane / methylvinylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends, dimethylpolysiloxane / methylvinylsiloxane copolymer with methyldivinylsiloxy groups sealed at both ends, dimethylpolysiloxane / methylvinylsiloxane copolymer with trivinylsiloxy groups sealed at both ends, and dimethylsiloxane / methylvinylsiloxane copolymer with trivinylsiloxy groups sealed at both ends.

[0056] The above component (A) may be used alone or in combination of two or more types.

[0057] <Component (B)> Component (B) is an organopolysiloxane resin having an alkenyl group bonded to a silicon atom. Examples of the alkenyl group bonded to the silicon atom, and organic groups other than the alkenyl group bonded to the silicon atom, are the same as those for component (A) above.

[0058] It is preferable that the aforementioned component (B) is represented by the following general formula (1). In general formula (1), the ratio of each constituent unit is expressed as a molar ratio. (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of the following is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, and g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, and g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.2.

[0059] R ３ Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0060] R ４ Examples of alkenyl groups include vinyl groups, allyl groups, butenyl groups, hexenyl groups, and octenyl groups, preferably alkenyl groups having 2 to 6 carbon atoms, and more preferably vinyl groups.

[0061] It is preferable that a is a number between 0 and 0.6, b is 0.05 and 0.4, c is 0 and 0.6, d is 0 and 0.5, e is 0 and 0.5, f is 0 and 0.8, and g is a number between 0 and 0.8. b + c + e is preferably 0.01 or more, more preferably 0.05 to 0.6. e + f + g is preferably 0.2 or more, more preferably 0.3 to 0.9. h is preferably a number between 0 and 0.1, and more preferably 0.

[0062] The amount of alkenyl groups in component (B) is preferably 0.040 moles or more per 100g, and more preferably 0.060 to 0.200 moles, from the viewpoint of the transparency and strength of the resulting cured product. That is, it is preferable that the amount of alkenyl groups in component (B) is 0.04 moles / 100g or more.

[0063] The above component (B) is preferably waxy or solid at 25°C. "Waxy" means a gum-like substance with almost no self-flowing properties, particularly with a Pa·s of 10,000 Pa·s or more, especially 100,000 Pa·s or more, at 25°C. Such a component (B) yields a cured product with excellent strength.

[0064] The amount of component (B) is preferably 30 to 80 parts by mass, and more preferably 40 to 70 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the amount is 30 parts by mass or more, the strength of the cured product is excellent, and if it is 80 parts by mass or less, the viscosity of the composition does not become too high and it is easy to handle.

[0065] Specific examples of the above (B) component include, but are not limited to, those having a constituent unit ratio represented by the following formula. [(CH ３ ) ３ SiO １／２ ] ０．４０ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．０６ (SiO ４／２ ) ０．５４ [(CH ２ =CH)(CH ３ ) SiO ２／２ ] ０．４０ [(CH ３ ) ２ SiO ２／２ ] ０．１５ (CH ３ SiO ３／２ ) ０．４５ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．２０[(CH ３ ) ２ SiO ２／２ ] ０．２５ (CH ３ SiO ３／２ ) ０．５５

[0066] The above component (B) may be used alone or in combination of two or more types.

[0067] <Component (C)> Component (C) is a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, and acts as a crosslinking agent that crosslinks with alkenyl groups bonded to silicon atoms contained in Component (A) and Component (B) through a hydrosilylation reaction.

[0068] The aforementioned (C) component is (R ５ HSiO ２／２ ) Unit (R ５ It is preferable that the linear alkylhydrogenpolysiloxane has an alkyl group and does not have an aryl group.

[0069] R ５ Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0070] The above component (C) is more preferably represented by the following general formula (2). ５ ３ SiO １／２ (R ５ HSiO ２／２ ) ｊ (R ５ ２ SiO ２／２ ) ｋ O １／２ SiR ５ ３ (2) (wherein, R ５The above is the same, and j and k are integers satisfying j≧1, k≧0, and 1≦j+k≦100, and the order of the siloxane units can be arbitrary.

[0071] j and k are such that j ≥ 1 and k ≥ 0, and j + k is preferably in the range of 1 ≤ j + k ≤ 100, and more preferably in the range of 5 ≤ j + k ≤ 50, from the viewpoint of compatibility with component (A) and component (B) above and workability.

[0072] Specific examples of the above (C) component include, but are not limited to, those represented by the following formula: [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ８ [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ３８ [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] １６ [(CH ３ ) ２ SiO ２／２ ] ２８ [H(CH ３ ) ２ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ２１ [(CH ３ ) ２ SiO ２／２ ] ７

[0073] The amount of component (C) is preferably such that there are 0.5 to 5.0 hydrogen atoms (SiH groups) bonded to silicon atoms in component (C) for each addition-reactive carbon-carbon double bond in the composition, and more preferably 0.7 to 3.0 hydrogen atoms. When this range is satisfied, crosslinking proceeds sufficiently, and a cured product with excellent hardness can be obtained.

[0074] The above component (C) may be used alone or in combination of two or more types.

[0075] <Component (D)> Component (D) is a platinum group metal catalyst and is not particularly limited as long as it is a component that promotes the hydrosilylation reaction between the alkenyl group bonded to the silicon atom in component (A) and component (B) and the hydrogen atom bonded to the silicon atom in component (C). Specific examples include platinum group metals such as platinum, palladium, and rhodium; platinum-based compounds such as chloroplatinic acid, alcohol-modified chloroplatinic acid, and coordination compounds of chloroplatinic acid with olefins, vinylsiloxanes, or acetylene compounds; and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium and chlorotris(triphenylphosphine)rhodium. However, platinum-based compounds are preferred, and coordination compounds of chloroplatinic acid and vinylsiloxanes are particularly preferred.

[0076] The above component (D) may be used alone or in combination of two or more types.

[0077] The amount of component (D) described above may be an effective amount as a catalyst, but it is preferably in the range of 1 to 500 ppm, and more preferably in the range of 1 to 100 ppm, in terms of the mass of platinum group metal elements relative to the total amount of components (A), (B), and (C). When this range is satisfied, the reaction rate of the addition reaction becomes appropriate, and a cured product with high strength can be obtained.

[0078] <Component (E)> Component (E) is silica, which is a component for imparting thixotropy to the addition-curing silicone composition of the present invention, and can also impart appropriate mechanical properties to the resulting cured product.

[0079] The BET specific surface area of ​​component (E) above is 100 m². ２Preferably 1 / g or more, and 200-400m ２ A value of / g is more preferable. With such a value, the composition can be given appropriate thixotropy, and a cured product with excellent transparency can be obtained. The BET specific surface area is measured in accordance with JIS Z 8830:2013 using a Macsorb® HM Model-1201 manufactured by Mountec Co., Ltd.

[0080] Examples of the above-mentioned silica include fumed silica (dried silica), precipitated silica (wet silica), and colloidal silica, but among these, fumed silica is particularly preferred.

[0081] That is, the above (E) component has a BET specific surface area of ​​100 m ２ It is preferable that the fumed silica is of a concentration of 1 / g or higher.

[0082] It is preferable that component (E) is surface-treated with dichlorodimethylsilane or trimethyldisilazane. Surface treatment makes it possible to suppress the increase in viscosity when storing the composition, resulting in excellent storage stability. Specific examples of such component (E) include Rheoroseal® DM30S manufactured by Tokuyama Corporation and Musil 120A manufactured by Shin-Etsu Chemical Co., Ltd.

[0083] The above component (E) may be used alone or in combination of two or more types.

[0084] The amount of component (E) is preferably 5 to 20 parts by mass, and more preferably 6 to 10 parts by mass, relative to 100 parts by mass of the total of components (A) and (B). Within this range, a composition with appropriate viscosity and thixotropy is obtained, and the transparency of the cured product is good.

[0085] <Component (F)> In order to improve the curability of the composition and the mechanical properties of the cured product, the addition-curing silicone composition of the present invention may be supplemented with a cyclic methylvinylsiloxane such as 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane or 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinylcyclopentasiloxane as component (F).

[0086] The above-mentioned component (F) may be used alone or in combination of two or more types.

[0087] The amount of component (F) is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the total of components (A) and (B). Within this range, the curability of the composition and the mechanical properties of the cured product can be improved.

[0088] <Component (G)> The addition-curing silicone composition of the present invention may contain an adhesive aid as component (G) in order to impart adhesion of the composition to various substrates.

[0089] The adhesive aid is an organic compound containing at least one or more functional groups from the group consisting of one or more (meth)acrylic groups, epoxy groups, alkoxysilyl groups, amide groups, and carboxylic acid anhydride groups per molecule. The adhesive aid may also contain an alkenyl group or hydrogen atom bonded to a silicon atom. In this case, a strong bond can be formed in the cured product through a hydrosilylation reaction between the alkenyl group bonded to the silicon atom in component (A) and component (B), or the hydrogen atom bonded to the silicon atom in component (C).

[0090] Adhesion aids containing Si-O bonds can be used, and specific examples include vinyltrimethoxysilane (trade name: KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.), γ-(glycidyloxypropyl)trimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), and γ-(methacryloxypropyl)trimethoxysilane (trade name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0091] Furthermore, siloxane compounds represented by the following structural formulas can also be suitably used as adhesive aids.

[0092] Furthermore, adhesive aids that do not contain silicon atoms can also be used. Specific examples include allyl glycidyl ether, vinylcyclohexene monooxide, diethyl 2-allylmalonate, allyl benzoate, diallyl phthalate, tetraallyl pyromellitic acid (trade name: TRIAM805, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and triallyl isocyanurate.

[0093] The above component (G) may be used alone or in combination of two or more.

[0094] The amount of component (G) is preferably 0.05 to 20 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the total of components (A) and (B).

[0095] <Component (H)> The addition-curing silicone composition of the present invention may contain a reaction control agent as component (H) in order to prevent thickening or gelation before the composition hardens.

[0096] Specific examples of reaction control agents include 3-methyl-1-butyne-3-ol, 3-methyl-1-pentin-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 1-ethynylcyclohexanol, ethinylmethyldecylcarbinol, 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butinoxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, etc. These may be used individually or in combination of two or more.

[0097] Among these, 1-ethynylcyclohexanol, ethinylmethyldecylcarbinol, and 3-methyl-3-trimethylsiloxy-1-butyne are preferred.

[0098] The amount of component (H) is preferably 0.01 to 2.0 parts by mass, and more preferably 0.05 to 0.5 parts by mass, relative to 100 parts by mass of the total of components (A) and (B). Within this range, the effect of reaction control is sufficiently exhibited.

[0099] Furthermore, the addition-curing silicone composition of the present invention may contain components other than those listed above (A) to (E) and components (F) to (H), depending on the purpose of the present invention. Specific examples of other components include antioxidants and flame retardants.

[0100] The addition-curing silicone composition of the present invention can be prepared by mixing components (A) to (E) above, and optionally components (F) to (H) above, and other components above.

[0101] The refractive index of the sodium D line of the addition-curing silicone composition of the present invention at 25°C is less than 1.42. If the refractive index is 1.42 or higher, i.e., if the content of aryl groups in the siloxane skeleton is high, the heat discoloration resistance of the cured product will be poor. The lower limit of the refractive index of the composition is preferably 1.41 or higher, taking into account the refractive index difference with silica.

[0102] In this invention, the refractive index is a value measured using a digital refractometer (RX-9000i, manufactured by Atago Co., Ltd.).

[0103] The shear rate of the addition-curing silicone composition of the present invention at 23°C is 10 s. －１ Shear rate 1s for viscosity －１ The viscosity ratio (thixotropy ratio) is 3.0 or higher, preferably 4.0 to 6.0. If the thixotropy ratio is less than 3.0, the fluidity is too high, making it difficult to maintain its shape, and it may be difficult to mold dome-shaped sealing materials, etc.

[0104] In this invention, the shear rate is 10s. －１ Viscosity and shear rate at 1s －１ The viscosity was measured using a rheometer (HAAKE MARS, manufactured by Thermo Fisher Scientific).

[0105] Furthermore, a second embodiment of the addition-curing silicone composition of the present invention includes components (A') to (E') described later. Each component will be described in detail below.

[0106] <Component (A')> Component (A') is (R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２ This is an alkenyl group. It consists of a linear organopolysiloxane with an alkenyl group content of 0.020 mol / 100g or more, and is a component that undergoes a hydrosilylation reaction with component (C') described later.

[0107] R １ Examples of alkyl groups in this context include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0108] R １ and R ２ Examples of alkenyl groups in this compound include vinyl groups, allyl groups, 3-butenyl groups, 5-hexenyl groups, and 7-octenyl groups, with a preference for alkenyl groups having 2 to 8 carbon atoms, and a preference for vinyl groups.

[0109] The amount of alkenyl groups in component (A') above is 0.020 moles or more per 100g, preferably 0.020 to 0.500 moles, and more preferably 0.025 to 0.200 moles. If the amount is 0.020 moles / 100g or more, the cured product will have excellent transparency. Furthermore, if the amount of alkenyl groups is 0.500 moles / 100g or less, the occurrence of cracks in the cured product can be suppressed.

[0110] The viscosity of component (A') at 25°C, as measured by a rotational viscometer, is preferably 5 to 3,000 mPa·s, and more preferably 10 to 2,000 mPa·s. Within this range, the resulting composition tends to have good workability and handling properties, and is less prone to the entrapment of bubbles and air during molding and curing.

[0111] Specific examples of component (A') above include, for example, dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends, dimethylsiloxane / methylvinylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends, dimethylpolysiloxane / methylvinylsiloxane copolymer with methyldivinylsiloxy groups sealed at both ends, dimethylpolysiloxane with trivinylsiloxy groups sealed at both ends, and dimethylsiloxane / methylvinylsiloxane copolymer with trivinylsiloxy groups sealed at both ends.

[0112] The above component (A') may be used alone or in combination of two or more types.

[0113] <Component (B')> Component (B') is an organopolysiloxane resin represented by the following general formula (1). In general formula (1), the ratio of each constituent unit is expressed as a molar ratio. (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３Each of them is independently an alkyl group, and R ４ Each of the following is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, and g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, and g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.2.

[0114] R ３ Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0115] R ４ Examples of alkenyl groups include vinyl groups, allyl groups, butenyl groups, hexenyl groups, and octenyl groups, preferably alkenyl groups having 2 to 6 carbon atoms, and more preferably vinyl groups.

[0116] It is preferable that a is a number between 0 and 0.6, b is 0.05 and 0.4, c is 0 and 0.6, d is 0 and 0.5, e is 0 and 0.5, f is 0 and 0.8, and g is a number between 0 and 0.8. b + c + e is preferably 0.01 or more, more preferably 0.05 to 0.6. e + f + g is preferably 0.2 or more, more preferably 0.3 to 0.9. h is preferably a number between 0 and 0.1, and more preferably 0.

[0117] The amount of alkenyl groups in component (B') above is preferably 0.040 moles or more per 100 g, and more preferably 0.060 to 0.200 moles, from the viewpoint of the transparency and strength of the resulting cured product.

[0118] The above component (B') is preferably waxy or solid at 25°C. "Waxy" means a gum-like substance with almost no self-flowing properties, particularly with a Pa·s of 10,000 Pa·s or more, especially 100,000 Pa·s or more, at 25°C. Such a (B') component yields a cured product with excellent strength.

[0119] The amount of component (B') is preferably 30 to 80 parts by mass, and more preferably 40 to 70 parts by mass, per 100 parts by mass of the total of components (A') and (B'). If the amount is 30 parts by mass or more, the strength of the cured product is excellent, and if it is 80 parts by mass or less, the viscosity of the composition does not become too high, resulting in excellent handling properties.

[0120] Specific examples of the above (B') component include, but are not limited to, those having the constituent unit ratio expressed by the following formula. [(CH ３ ) ３ SiO １／２ ] ０．４０ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．０６ (SiO ４／２ ) ０．５４ [(CH ２ =CH)(CH ３ ) SiO ２／２ ] ０．４０ [(CH ３ ) ２ SiO ２／２ ] ０．１５ (CH ３ SiO ３／２ ) ０．４５ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ０．２０ [(CH ３ ) ２ SiO ２／２ ] ０．２５ (CH ３ SiO ３／２ ) ０．５５

[0121] The above component (B') may be used alone or in combination of two or more types.

[0122] <(C') component> The (C') component is (R ５ HSiO ２／２ ) Unit (R ５It is a linear alkylhydrogenpolysiloxane having an alkyl group and no aryl group, and acts as a crosslinking agent that crosslinks with alkenyl groups bonded to silicon atoms contained in the above components (A') and (B') through a hydrosilylation reaction.

[0123] R ５ Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group. Among these, alkyl groups having 1 to 8 carbon atoms are preferred, and methyl groups are more preferred from the viewpoint of the strength and heat resistance of the cured product.

[0124] The above (C') component is more preferably represented by the following general formula (2). ５ ３ SiO １／２ (R ５ HSiO ２／２ ) ｊ (R ５ ２ SiO ２／２ ) ｋ O １／２ SiR ５ ３ (2) (wherein, R ５ The above is the same, and j and k are integers satisfying j≧1, k≧0, and 1≦j+k≦100, and the order of the siloxane units can be arbitrary.

[0125] j and k are such that j ≥ 1 and k ≥ 0, and j + k is preferably in the range of 1 ≤ j + k ≤ 100, and more preferably in the range of 5 ≤ j + k ≤ 50, from the viewpoint of compatibility with the above (A') and (B') components and workability.

[0126] Specific examples of the above (C') component include, but are not limited to, those represented by the following formula: [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ８ [(CH ３ )３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ３８ [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] １６ [(CH ３ ) ２ SiO ２／２ ] ２８ [H(CH ３ ) ２ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ２１ [(CH ３ ) ２ SiO ２／２ ] ７

[0127] The amount of component (C') is preferably such that there are 0.5 to 5.0 hydrogen atoms (SiH groups) bonded to silicon atoms in component (C') for each addition-reactive carbon-carbon double bond in the composition, and more preferably 0.7 to 3.0 hydrogen atoms. When this range is satisfied, crosslinking proceeds sufficiently, and a cured product with excellent hardness can be obtained.

[0128] The above (C') component may be used alone or in combination of two or more types.

[0129] <Component (D')> Component (D') is a platinum group metal catalyst and is not particularly limited as long as it is a component that promotes the hydrosilylation reaction between the alkenyl group bonded to the silicon atom in component (A') and component (B') and the hydrogen atom bonded to the silicon atom in component (C'). Specific examples include platinum group metals such as platinum, palladium, and rhodium; platinum-based compounds such as chloroplatinic acid, alcohol-modified chloroplatinic acid, and coordination compounds of chloroplatinic acid with olefins, vinylsiloxanes, or acetylene compounds; and platinum group metal compounds such as tetrakis(triphenylphosphine)palladium and chlorotris(triphenylphosphine)rhodium. However, platinum-based compounds are preferred, and coordination compounds of chloroplatinic acid and vinylsiloxanes are particularly preferred.

[0130] The above component (D') may be used alone or in combination of two or more types.

[0131] The amount of component (D') described above may be an effective amount as a catalyst, but it is preferably in the range of 1 to 500 ppm, and more preferably in the range of 1 to 100 ppm, when calculated by mass of platinum group metal elements relative to the total amount of components (A'), (B'), and (C'). When this range is satisfied, the reaction rate of the addition reaction becomes appropriate, and a cured product with high strength can be obtained.

[0132] <(E') component> The (E') component has a BET specific surface area of ​​100 m². ２ This component contains silica of a concentration of 1 / g or more, and is a component for imparting thixotropy to the addition-curing silicone composition of the present invention, and can also impart appropriate mechanical properties to the resulting cured product.

[0133] The BET specific surface area of ​​the above (E') component is 100 m². ２ It is 1 / g or more, and 200-400m ２ / g is preferred. BET specific surface area is 100 m². ２ A concentration of 1 / g or higher imparts appropriate thixotropy to the composition, resulting in excellent transparency of the cured product. The BET specific surface area is measured using a Macsorb® HM Model-1201 manufactured by Mountec Co., Ltd., in accordance with JIS Z 8830:2013.

[0134] Examples of the above-mentioned silica include fumed silica (dried silica), precipitated silica (wet silica), and colloidal silica, but among these, fumed silica is particularly preferred.

[0135] It is preferable that the (E') component is surface-treated with dichlorodimethylsilane or trimethyldisilazane. Surface treatment makes it possible to suppress the increase in viscosity during storage of the composition, resulting in excellent storage stability.

[0136] The above (E') component may be used alone or in combination of two or more types.

[0137] The amount of component (E') is 5 to 20 parts by mass, preferably 6 to 10 parts by mass, relative to 100 parts by mass of the total of components (A') and (B'). If it is outside this range, a composition with appropriate viscosity and thixotropy cannot be obtained, and the transparency of the cured product will also be poor.

[0138] Furthermore, the addition-curing silicone composition of the present invention may contain, in addition to the above components (A') to (E'), the above components (F) to (H) and the above other components. The amount of the above components (F) to (H) is the same as above, except that the total amount of the above components (A') and (B') is 100 parts by mass instead of the total amount of the above components (A) and (B).

[0139] Furthermore, it is preferable that the alkyl group in component (A'), component (B'), and component (C') is a methyl group, and that the alkenyl group in component (A') and component (B') is a vinyl group.

[0140] The addition-curing silicone composition of the present invention can be prepared by mixing the above components (A') to (E'), and optionally the above components (F) to (H), and the other components.

[0141] [Cured product] Furthermore, the present invention provides a cured product (silicone cured product) which is obtained by curing the addition-curing type silicone composition described above.

[0142] The cured product of the present invention has a light transmittance of 50% or more at a wavelength of 400 nm (at 25°C) at a thickness of 2 mm and excellent heat discoloration resistance, making it useful as an electrical and electronic component, particularly as a lens material and an LED encapsulation material. A light transmittance of less than 50% is undesirable because it results in poor transparency. There is no particular upper limit to the light transmittance, but for example, it can be 90% or less.

[0143] In this invention, the light transmittance is a value measured using a spectrophotometer U-3900 (manufactured by Hitachi High-Tech Science Corporation).

[0144] The curing of the addition-curing silicone composition of the present invention can be carried out under known conditions, for example, by curing at 120 to 200°C for 30 minutes to 2 hours. In particular, from the viewpoint of protecting electronic devices such as LED elements, the hardness of the cured product obtained by curing the composition is preferably 70 or higher on the durometer type A hardness at 25°C according to JIS K 6253-3:2023, and particularly preferably 70 to 95. The curing conditions for achieving a durometer type A hardness of 70 or higher can usually be obtained by heating and curing the addition-curing silicone composition of the present invention at 150 to 180°C for 30 minutes to 2 hours.

[0145] [Lens] The present invention also provides a lens made of the cured material described above.

[0146] [Optical Semiconductor Device] The present invention also provides an optical semiconductor device in which an optical element is sealed with the cured product described above.

[0147] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0148] [Examples 1-4, Comparative Examples 1-5] Addition-curing silicone compositions were prepared by mixing the following components in the amounts shown in Table 1. The values ​​for each component in Table 1 represent parts by mass. The [Si-H] / [Si-Vi] ratio represents the ratio of the number of hydrogen atoms bonded to silicon atoms to one alkenyl group bonded to silicon atoms in the composition. The viscosity of each component at 25°C was measured using a rotational viscometer.

[0149] Furthermore, the meanings of the abbreviations for each siloxane unit are as follows: M: (CH ３ ) ３ SiO １／２ M Ｖｉ : (CH ２ =CH)(CH ３ ) ２ SiO １／２ D Ｈ : H(CH ３ ) SiO ２／２ Q: SiO ４／２

[0150] (A) Components: (A-1) Dimethylpolysiloxane with 0.027 mol / 100g vinyl group content and viscosity of 1,500 mPa·s at 25°C, with trivinylsiloxy groups sealed at both ends. (A-2) Dimethylsiloxane / methylvinylsiloxane copolymer with 0.068 mol / 100g vinyl group content and viscosity of 200 mPa·s at 25°C, with dimethylvinylsiloxy groups sealed at both ends. (A-3) Dimethylpolysiloxane with 0.18 mol / 100g vinyl group content and viscosity of 10 mPa·s at 25°C, with dimethylvinylsiloxy groups sealed at both ends. (A-4) Dimethylpolysiloxane with 0.006 mol / 100g vinyl group content and viscosity of 5,000 mPa·s at 25°C, with dimethylvinylsiloxy groups sealed at both ends. (A-5) Dimethylpolysiloxane with vinyl group content of 0.0075 mol / 100g and viscosity of 100,000 mPa·s at 25°C, with trivinylsiloxy groups sealed at both ends. (A-6) Dimethylsiloxane / diphenylsiloxane copolymer with vinyl group content of 0.020 mol / 100g and viscosity of 450 mPa·s at 25°C (percentage of phenyl groups relative to the total number of methyl and phenyl groups: 5 mol%).

[0151] (B) Component: M Unit: M ＶｉUnit: A solid organopolysiloxane resin at 25°C, expressed in a molar ratio of Q units of 0.402:0.058:0.540 (vinyl group content: 0.082 mol / 100g).

[0152] (C) Component: M ２ D Ｈ ８ Linear methylhydrogenpolysiloxane represented by (SiH content: 0.0124 mol / g)

[0153] (D) Component: A solution obtained by diluting the reaction product of hexachloroplatinic acid and 1,3-divinyltetramethyldisiloxane with dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends, with a viscosity of 600 mPa·s (platinum concentration 1.0% by mass).

[0154] (E) Component: (E-1) BET specific surface area is 230 m² ２ The material is fumed silica (Rheoroseal® DM30S, manufactured by Tokuyama Corporation) with a surface treatment of dichlorodimethylsilane (E-2) BET specific surface area of ​​200 m². ２ The material is fumed silica (Musil 120A, manufactured by Shin-Etsu Chemical Co., Ltd.) with a surface treatment of trimethyldisilazane (E-3) and a BET specific surface area of ​​3.6 m². ２ Crystalline silica (FB-3SDC, manufactured by Denka Co., Ltd.) / g

[0155] (F) Component: 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane

[0156] (G) Components: (G-1) Triallyl isocyanurate (G-2) Organopolysiloxane represented by the following structural formula (4) (SiH content: 0.0085 mol / g)

[0157] (H) Ingredient: Ethinylcyclohexanol

[0158]

[0159] <Measurement Method> The physical properties of the addition-curing silicone compositions and their cured products obtained in Examples 1-4 and Comparative Examples 1-5 were measured according to the following measurement method. The results are shown in Table 2.

[0160] [Refractive Index] The refractive index of the composition was measured using a digital refractometer (ATAGO Corporation, RX-9000i) with sodium D line as the light source at 25°C.

[0161] [Viscosity] Using a rheometer (Thermo Fisher Scientific, HAAKE MARS), the shear rate of the composition at 23°C was measured at 1 s. －１ and 10s －１ The shear viscosity was measured after 60 seconds.

[0162] [Thixotropic ratio] Shear rate at 23°C: 10s －１ Shear rate 1s for viscosity －１ The ratio of viscosity was calculated and defined as the thixotropic ratio. Thixotropic ratio = viscosity (1 s) －１ ) / viscosity (10s －１ )

[0163] [Hardness of the cured material] The composition was poured into a mold to a thickness of 2 mm and cured by heating at 150°C for 1 hour. Three of the resulting 2 mm thick cured materials were stacked (total thickness 6 mm), and the durometer type A hardness at 25°C was measured using an automatic rubber hardness tester (P2-A, manufactured by Polymer Instruments Co., Ltd.) in accordance with JIS K 6253-3:2023.

[0164] [Light transmittance] The composition was poured into a mold to a thickness of 2 mm and cured by heating at 150°C for 1 hour. The light transmittance of the resulting cured material at a wavelength of 400 nm at 25°C (optical path length 2 mm) was measured using a spectrophotometer U-3900 (manufactured by Hitachi High-Tech Science Corporation).

[0165] [Heat Resistance and Discoloration] The composition was poured into a mold to a thickness of 2 mm, heated at 150°C for 4 hours, and the resulting cured product was exposed to a 200°C environment for 100 hours. The presence or absence of discoloration of the cured product was then checked and evaluated as follows: Good: No discoloration. Poor: Discoloration present.

[0166]

[0167] As shown in Table 2 above, the addition-curing silicone compositions of Examples 1 to 4 had a high thixotropy of 4.5 or higher and a refractive index of less than 1.42, yet the resulting cured products exhibited excellent light transmittance, and furthermore, there was no discoloration of the cured products after the heat resistance test.

[0168] On the other hand, in Comparative Examples 1 and 2, where component (A) was changed to one with a lower vinyl group content, the light transmittance of the cured product was inferior. In this case, although the light transmittance of the cured product increased by reducing the amount of component (E), the thixotropic ratio was low at 1.9, resulting in a composition with poor shape retention (Comparative Example 3). Furthermore, in Comparative Example 4, where component (A) was changed to one with a phenyl group and the refractive index was increased, the light transmittance of the cured product was good, but the heat discoloration resistance was poor. Comparative Example 5 used silica with a large particle size, but the thixotropic ratio of the composition was low, resulting in poor transparency of the cured product.

[0169] This specification encompasses the following aspects: [1]: Addition-curing silicone composition comprising: (A) a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain; (B) an organopolysiloxane resin having alkenyl groups bonded to silicon atoms; (C) a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms; (D) a platinum group metal catalyst; and (E) silica, wherein the refractive index of the sodium D line at 25°C is less than 1.42, and the shear rate at 23°C is 10 s. －１ Shear rate 1s for viscosity －１ An addition-curing silicone composition characterized in that the viscosity ratio at is 3.0 or higher, and the light transmittance at a wavelength of 400 nm at a thickness of 2 mm obtained by curing the addition-curing silicone composition is 50% or higher. [2]: The (A) component is (R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２The addition-curing silicone composition according to [1] above, characterized in that it consists of an alkenyl group and is a linear organopolysiloxane with an alkenyl group content of 0.020 mol / 100 g or more. [3]: The addition-curing silicone composition according to [1] or [2] above, characterized in that the (B) component is represented by the following general formula (1). (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of the following is an alkenyl group, X is a hydrogen atom or an alkyl group, a, b, c, d, e, f, g are numbers such that a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number from 0 to 0.2.) [4]: ​​The addition-curing silicone composition according to any one of the above [1] to [3], characterized in that the amount of alkenyl groups in component (B) is 0.04 mol / 100g or more. [5]: The component (C) is (R ５ HSiO ２／２ ) Unit (R ５The addition-curing silicone composition according to any one of the above [1] to [4], characterized in that it has an alkyl group and is a linear alkylhydrogenpolysiloxane that does not have an aryl group. [6]: The component (E) has a BET specific surface area of ​​100 m ２ An addition-curing silicone composition according to any one of [1] to [5] above, characterized in that it is fumed silica of 1 / g or more. [7]: An addition-curing silicone composition according to any one of [1] to [6] above, characterized in that the (E) component is surface-treated with dichlorodimethylsilane or trimethyldisilazane. [8]: An addition-curing silicone composition according to any one of [1] to [7] above, characterized in that the amount of the (E) component is 5 to 20 parts by mass per 100 parts by mass of the total of the (A) component and the (B) component. [9]: An addition-curing silicone composition, wherein (A')(R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２ (R) is an alkenyl group. (B') A linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, and an organopolysiloxane resin represented by the following general formula (1), and (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ )ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of these is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.2. ) (C')(R ５ HSiO ２／２ ) Unit (R ５ (D') a linear alkylhydrogenpolysiloxane having an alkyl group and no aryl group, (E') a platinum group metal catalyst, and (E') a BET specific surface area of ​​100 m ２

[10] : Addition-curing silicone composition characterized by containing: silica of 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B').

[11] : Addition-curing silicone composition according to [9], characterized in that the alkyl group in component (A'), component (B'), and component (C') is a methyl group, and the alkenyl group in component (A') and component (B') is a vinyl group.

[12] : Cured product characterized in that any one of the addition-curing silicone compositions from [1] to

[10] has been cured.

[13] : Cured product according to

[11] , characterized in that it has a durometer type A hardness of 70 to 95.

[14] : Lens characterized by being made of the cured product of

[11] or

[12] .

[15] : Optoelectronic device characterized in that an optical element is sealed with the cured product of

[11] or

[12] .

[0170] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. An addition-curing silicone composition comprising: (A) a linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain; (B) an organopolysiloxane resin having alkenyl groups bonded to silicon atoms; (C) a linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms; (D) a platinum group metal catalyst; and (E) silica, wherein the refractive index of the sodium D line at 25°C is less than 1.42, and the shear rate at 23°C is 10 s. －１ Shear rate 1s for viscosity －１ An addition-curing silicone composition characterized by having a viscosity ratio of 3.0 or higher, and a light transmittance of 400 nm at a wavelength of 50% or higher at a thickness of 2 mm of the cured product obtained by curing the addition-curing silicone composition.

2. The component (A) is (R １ ２ R ２ SiO １／２ ), and (R １ ２ SiO ２／２ ), where (R １ is independently an alkyl group or an alkenyl group, and R ２ is an alkenyl group), and is a linear organopolysiloxane having an alkenyl group content of 0.020 mol / 100 g or more. The addition-curing silicone composition according to claim 1, characterized in that.

3. The addition-curing silicone composition according to claim 1, characterized in that the component (B) is represented by the following general formula (1). (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of the following is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, and g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, and g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.

2.

4. The addition-curing silicone composition according to claim 1, characterized in that the amount of alkenyl groups in component (B) is 0.04 mol / 100 g or more.

5. The above (C) component is (R ５ HSiO ２／２ ) Unit (R ５ The addition-curing silicone composition according to claim 1, characterized in that it is a linear alkylhydrogenpolysiloxane having an alkyl group and not having an aryl group.

6. The above-mentioned component (E) has a BET specific surface area of ​​100 m². ２ The addition-curing silicone composition according to claim 1, characterized in that it is fumed silica of 1g or more.

7. The addition-curing silicone composition according to claim 1, characterized in that the component (E) is surface-treated with dichlorodimethylsilane or trimethyldisilazane.

8. The addition-curing silicone composition according to claim 1, characterized in that the amount of component (E) is 5 to 20 parts by mass with respect to 100 parts by mass of the total of components (A) and (B).

9. Addition-curing silicone composition, (A')(R １ ２ R ２ SiO １／２ ) units and (R １ ２ SiO ２／２ ) Unit (R １ Each of these is independently an alkyl group or an alkenyl group, R ２ (R) is an alkenyl group. (B') A linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, and an organopolysiloxane resin represented by the following general formula (1), and (R ３ ３ SiO １／２ ) ａ (R ４ R ３ ２ SiO １／２ ) ｂ (R ４ R ３ SiO ２／２ ) ｃ (R ３ ２ SiO ２／２ ) ｄ (R ４ SiO ３／２ ) ｅ (R ３ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (XO １／２ ) ｈ (1) (wherein, R ３ Each of them is independently an alkyl group, and R ４ Each of these is independently an alkenyl group, X is a hydrogen atom or an alkyl group, and a, b, c, d, e, f, g are numbers satisfying a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, where b+c+e>0, e+f+g>0, and a+b+c+d+e+f+g=1, and h is a number between 0 and 0.

2. ) (C')(R ５ HSiO ２／２ ) Unit (R ５ (D') a linear alkylhydrogenpolysiloxane having an alkyl group and no aryl group, (E') a platinum group metal catalyst, and (E') a BET specific surface area of ​​100 m ２ An addition-curing silicone composition characterized by containing: silica of 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B') / g or more.

10. The addition-curing silicone composition according to claim 9, characterized in that the alkyl group in component (A'), component (B'), and component (C') is a methyl group, and the alkenyl group in component (A') and component (B') is a vinyl group.

11. A cured product characterized in that it is a cured product obtained by curing an addition-curing silicone composition according to any one of claims 1 to 10.

12. The cured product according to claim 11, characterized in that its durometer type A hardness is 70 to 95.

13. A lens characterized by being made of the cured product described in claim 11.

14. An optoelectronic device characterized in that an optical element is sealed with the cured product described in claim 11.

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