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

Abstract

The present invention provides an addition-curing silicone composition that has thixotropy and yields a cured product with excellent transparency and heat discoloration resistance upon curing, a cured product thereof, a lens made from the cured product, and an optoelectronic device. [Solution] 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 is less than 1.42 and the shear rate is 10s. -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 a cured product obtained by curing the composition of 50% or higher.

Description

[Technical Field]

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

[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. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-089913 [Patent Document 2] Japanese Patent Publication No. 2020-132739 [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention has been made in view of the above circumstances, and aims to provide an addition-curing type silicone composition that has thixotropy and can provide a cured product that exhibits excellent transparency and heat discoloration resistance upon curing, a cured product thereof, a lens made from the cured product, and an optoelectronic device. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides an addition-curing silicone composition, (A) A linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain, (B) Organopolysiloxane resin having alkenyl groups bonded to silicon atoms, (C) A linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, (D) Platinum group metal catalysts, (E) Silica and, It contains a sodium D-line with a refractive index of less than 1.42 at 25°C and a shear rate of 10s at 23°C. -1 Shear rate 1s for viscosity -1 The present invention provides an addition-curing silicone composition 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.

[0010] The addition-curable silicone composition of the present invention, despite being an addition-curable silicone composition having a refractive index of less than 1.42, can provide a cured product that exhibits high transparency after curing and excellent heat discoloration resistance even when it contains silica and has thixotropy.

[0011] Further, in the present invention, the component (A) is (R 1 2R 2 SiO 1 / 2 ) unit and (R 1 2SiO 2 / 2 ) unit (R 1 each independently represents an alkyl group or an alkenyl group, and R 2 represents an alkenyl group.) It is preferably a linear organopolysiloxane composed of the above and having an alkenyl group content of 0.020 mol / 100 g or more.

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

[0013] Further, in the present invention, the component (B) is preferably one represented by the following general formula (1). (R 3 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 ) g (XO 1 / 2 ) h (1) (In the formula, R 3 each independently represents an alkyl group, and R 4Each 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 moles / 100g or more.

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

[0017] Furthermore, in the present invention, the above (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.

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

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

[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 per 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, in the present invention, the addition-curing type silicone composition is (A')(R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and R 2 (is an alkenyl group.) consists of a linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, (B') An organopolysiloxane resin represented by the following general formula (1), (R 3 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 )g (XO 1 / 2 ) h (1) (In the formula, R 3 Each of them is 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. (C')(R 5 HSiO 2 / 2 ) Unit (R 5 (is an alkyl group.) and a linear alkylhydrogenpolysiloxane that does not have an aryl group, (D') Platinum group metal catalyst, (E')BET specific surface area is 100m 2 Silica of / g or more: 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B'), The present invention provides an addition-curing silicone composition containing the following:

[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 encapsulating 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 between 70 and 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. [Effects of the Invention]

[0037] As described above, the addition-curing silicone composition of the present invention, despite being an addition-curing silicone composition with a refractive index of less than 1.42, can provide a cured product that is highly transparent and has excellent heat discoloration resistance after curing, even when silica is included as a thixotropic agent. It is useful for electrical and electronic components, particularly as lens materials and LED encapsulation materials. [Modes for carrying out the invention]

[0038] As described above, there has been a need to develop an addition-curing silicone composition that has a refractive index of less than 1.42 (i.e., does not contain aryl groups in the silicone skeleton or has a low aryl group content), yet provides a cured product that is highly transparent and has excellent heat discoloration resistance after curing, even when silica is included as a thixotropic agent.

[0039] As a result of diligent research into the above problems, the inventors of the present invention have found that an addition-curing silicone composition containing components (A) to (E) or (A') to (E'), as described below, can solve the above problems, and have completed the present invention.

[0040] In other words, the present invention is an addition-curing silicone composition, (A) A linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain, (B) Organopolysiloxane resin having alkenyl groups bonded to silicon atoms, (C) A linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, (D) Platinum group metal catalysts, (E) Silica and, It contains a sodium D-line with a refractive index of less than 1.42 at 25°C and a shear rate of 10s at 23°C. -1 Shear rate 1s for viscosity -1 The addition-curing silicone composition has a viscosity ratio of 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.

[0041] Furthermore, the present invention relates to an addition-curing silicone composition, (A')(R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and R 2is an alkenyl group.) a linear organopolysiloxane having an alkenyl group content of 0.020 mol / 100g or more, (B') an organopolysiloxane resin represented by the following general formula (1), (R 3 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 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 are each independently an alkyl group, R 4 are each independently an alkenyl group, X is a hydrogen atom or an alkyl group, a, b, c, d, e, f, g each satisfy a≧0, b≧0, c≧0, d≧0, e≧0, f≧0, g≧0, with the proviso 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 alkylhydrogen polysiloxane having (R 5 HSiO 2 / 2 ) units (wherein R 5 is an alkyl group) and having no aryl group, (D') a platinum group metal catalyst, (E') silica having a BET specific surface area of 100 m 2 / g or more: 5 to 20 parts by mass relative to 100 parts by mass of the total of component (A') and component (B'), An addition-curable silicone composition comprising the above components.

[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 10s. -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 obtained by curing the addition-curing silicone composition is 50% or higher. Each component will be described in detail below.

[0044] <(A) component> 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] Besides alkenyl groups bonded to silicon atoms, alkyl groups are preferred as organic groups. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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.

[0049] Therefore, component (A) above is (R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and 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, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and 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, dimethylsiloxane-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.

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

[0057] <(B) component> 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 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 ) g (XO 1 / 2 ) h (1) (In the formula, R 3 Each of them is 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 3Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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, with a preference for alkenyl groups having 2 to 6 carbon atoms, and a preference for vinyl groups.

[0061] It is preferable that a is a number between 0 and 0.6, b is a number between 0.05 and 0.4, c is a number between 0 and 0.6, d is a number between 0 and 0.5, e is a number between 0 and 0.5, f is a number between 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) above 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) above 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, exhibiting a pressure of 10,000 Pa·s or more, particularly 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, resulting in excellent handling properties.

[0065] Specific examples of component (B) above include, but are not limited to, those having a constituent unit ratio represented by the following formula. [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.06 (SiO 4 / 2 ) 0.54 [(CH2=CH)(CH3)SiO 2 / 2 ] 0.40 [(CH3)2SiO 2 / 2 ] 0.15 (CH3SiO 3 / 2 ) 0.45 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.20 [(CH3)2SiO 2 / 2 ] 0.25 (CH3SiO 3 / 2 ) 0.55

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

[0067] <(C) component> 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 in components (A) and (B) through a hydrosilylation reaction.

[0068] The aforementioned (C) component is (R 5 HSiO 2 / 2 ) Unit (R 5It 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, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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). R 5 3SiO 1 / 2 (R 5 HSiO 2 / 2 ) j (R 5 2SiO 2 / 2 ) k O 1 / 2 SiR 5 3(2) (In the formula, 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.

[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 the above components (A) and (B).

[0072] Specific examples of the above (C) component include, but are not limited to, those represented by the following formula. [(CH3)3SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ]8 [(CH3)3SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ] 38 [(CH3)3SiO1 / 2 ]2[(CH3)HSiO 2 / 2 ] 16 [(CH3)2SiO 2 / 2 ] 28 [H(CH3)2SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ] 21 [(CH3)2SiO 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 met, 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] <(D) component> 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 components.

[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, 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.

[0078] <(E) component> 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 100m². 2 Preferably 200-400m / g or more 2 / g is more preferable. With this, 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 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 1 / g or more.

[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, per 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] <(F) component> The addition-curing silicone composition of the present invention may contain, as component (F), 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 to improve the curability of the composition and the mechanical properties of the cured product.

[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, per 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] <(G) component> 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. [ka]

[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 types.

[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] <(H) component> 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-butynate-3-ol, 3-methyl-1-pentin-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, ethinylmethyldecylcarbinol, 3-methyl-3-trimethylsiloxy-1-butynate, 3-methyl-3-trimethylsiloxy-1-pentynate, 3,5-dimethyl-3-trimethylsiloxy-1-hexyn, 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 the above components (A) to (E), and optionally the above components (F) to (H), and the other components.

[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 (ATAGO Corporation, RX-9000i).

[0103] The shear rate of the addition-curing silicone composition of the present invention at 23°C is 10s. -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 (Thermo Fisher Scientific, HAAKE MARS).

[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] <(A') component> (A') component is (R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and 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 the (C') component described later.

[0107] R 1 Examples of alkyl groups in this context include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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 between 0.020 and 0.500 moles, and more preferably between 0.025 and 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 the above (A') component 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, dimethylsiloxane-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] <(B') component> 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 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 ) g (XO 1 / 2 ) h (1) (In the formula, R 3 Each of them is 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, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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, with a preference for alkenyl groups having 2 to 6 carbon atoms, and a preference for vinyl groups.

[0116] It is preferable that a is a number between 0 and 0.6, b is a number between 0.05 and 0.4, c is a number between 0 and 0.6, d is a number between 0 and 0.5, e is a number between 0 and 0.5, f is a number between 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 100g, 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, exhibiting a pressure of 10,000 Pa·s or more, particularly 100,000 Pa·s or more, at 25°C. Such a component (B') 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 a constituent unit ratio represented by the following formula. [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.06 (SiO 4 / 2 ) 0.54 [(CH2=CH)(CH3)SiO 2 / 2 ] 0.40 [(CH3)2SiO 2 / 2 ] 0.15 (CH3SiO 3 / 2 ) 0.45 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.20 [(CH3)2SiO 2 / 2 ] 0.25 (CH3SiO 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 5(I is an alkyl group.) It is a linear alkylhydrogenpolysiloxane that has an alkyl group and does not have an 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, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, and n-decyl groups. 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). R 5 3SiO 1 / 2 (R 5 HSiO 2 / 2 ) j (R 5 2SiO 2 / 2 ) k O 1 / 2 SiR 5 3(2) (In the formula, 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 components (A') and (B') and workability.

[0126] Specific examples of the above (C') component include, but are not limited to, those represented by the following formula. [(CH3)3SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ]8 [(CH3)3SiO 1 / 2]2[(CH3)HSiO 2 / 2 ] 38 [(CH3)3SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ] 16 [(CH3)2SiO 2 / 2 ] 28 [H(CH3)2SiO 1 / 2 ]2[(CH3)HSiO 2 / 2 ] 21 [(CH3)2SiO 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 met, 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] <(D') component> 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 (D') component may be used alone or in combination of two or more types.

[0131] The blending amount of the component (D') may be an effective amount as a catalyst, and is preferably in the range of 1 to 500 ppm, more preferably 1 to 100 ppm, in terms of mass of platinum group metal element, based on the total amount of the component (A'), the component (B') and the component (C'). When this range is satisfied, the reaction rate of the addition reaction becomes appropriate, and a cured product having high strength can be obtained.

[0132] <(E’) component> The component (E') is silica having a BET specific surface area of 100 m 2 / g or more, which is a component for imparting thixotropy to the addition-curable silicone composition of the present invention, and is capable of imparting appropriate mechanical properties to the resulting cured product.

[0133] The BET specific surface area of the component (E') is 100 m 2 / g or more, and preferably 200 to 400 m 2 / g. When the BET specific surface area is 100 m 2 / g or more, appropriate thixotropy can be imparted to the composition, and the cured product will have excellent transparency. The BET specific surface area is a value measured in accordance with JIS Z 8830:2013 using Macsorb (registered trademark) HM Model-1201 manufactured by Mountec Co., Ltd.

[0134] Examples of the silica include fumed silica (dry silica), precipitated silica (wet silica), colloidal silica, etc. Among these, fumed silica is particularly preferred.

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

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

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

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

[0139] Further, it is preferable that the alkyl groups in the component (A'), the component (B'), and the component (C') are methyl groups, and the alkenyl groups in the component (A') and the component (B') are vinyl groups.

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

[0141] [Cured Product] Furthermore, the present invention provides a cured product (silicone cured product) which is a cured product obtained by curing the addition-curable 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 (25°C) for a thickness of 2 mm, and is excellent in heat discoloration resistance, so it is useful as an electrical and electronic component, particularly as a lens material or an LED sealing material. When the light transmittance is less than 50%, the transparency becomes poor, which is not preferable.

[0143] In the present 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, 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, from the viewpoint of protecting electronic devices such as LED elements. 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] Furthermore, the present invention provides a lens made of the cured material described above.

[0146] [Optical Semiconductor Equipment] Furthermore, the present invention provides an optoelectronic device in which an optical element is sealed with the cured material described above. [Examples]

[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 a silicon atom to one alkenyl group bonded to a silicon atom 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:(CH3)3SiO 1 / 2 M Vi :(CH2=CH)(CH3)2SiO 1 / 2 D H :H(CH3)SiO 2 / 2 Q:SiO 4 / 2

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

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

[0152] (C) Ingredients: M2D H Linear methylhydrogenpolysiloxane represented by 8 (SiH content: 0.0124 mol / g)

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

[0154] Component (E): (E-1) Fumed silica having a BET specific surface area of 230 m 2 / g and surface-treated with dichlorodimethylsilane (Reolosil (registered trademark) DM30S, manufactured by Tokuyama Corporation) (E-2) Fumed silica having a BET specific surface area of 200 m 2 / g and surface-treated with trimethyldisilazane (Musil 120A, manufactured by Shin-Etsu Chemical Co., Ltd.) (E-3) Crystalline silica having a BET specific surface area of 3.6 m 2 / g (FB-3SDC, manufactured by Denka Company Limited)

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

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

Chemical Formula

[0157] Component (H): ethynylcyclohexanol

[0158]

Table 1

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

[0160] [Refractive index] A digital refractometer (ATAGO Corporation, RX-9000i) was used to measure the refractive index of the composition at 25°C using sodium D lines as the light source.

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

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

[0163] [Hardness of hardened 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-resistant and colorfast] 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. After that, the presence or absence of discoloration of the cured product was checked and evaluated as follows. Good: No discoloration Defect: Discoloration present

[0166] [Table 2]

[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, a refractive index of less than 1.42, yet exhibited excellent light transmittance of the resulting cured product, and showed no discoloration of the cured product after heat resistance testing.

[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 includes the following embodiments: [1]: Addition-curing silicone composition, (A) A linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain, (B) Organopolysiloxane resin having alkenyl groups bonded to silicon atoms, (C) A linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, (D) Platinum group metal catalysts, (E) Silica and, It contains a sodium D-line with a refractive index of less than 1.42 at 25°C and a shear rate of 10s at 23°C. -1 Shear rate 1s for viscosity -1An addition-curing silicone composition characterized by having a viscosity ratio of 3.0 or higher, and a light transmittance of 400 nm at a thickness of 2 mm obtained by curing the addition-curing silicone composition being 50% or higher. [2]: The above (A) component is (R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and R 2 The addition-curing silicone composition according to [1] above, characterized in that it consists of (wherein is an alkenyl group) and the amount of alkenyl groups is 0.020 mol / 100g or more, and is a linear organopolysiloxane. [3]: The addition-curing silicone composition according to [1] or [2] above, characterized in that the component (B) is represented by the following general formula (1). (R 3 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 ) g (XO 1 / 2 ) h (1) (In the formula, R 3 Each of them is an alkyl group, and R 4Each 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]: An addition-curing silicone composition according to any one of [1] to [3] above, characterized in that the amount of alkenyl groups in component (B) is 0.04 mol / 100g or more. [5]: The above (C) component is (R 5 HSiO 2 / 2 ) Unit (R 5 The addition-curing silicone composition according to any one of the above [1] to [4] is characterized by having an alkyl group and being a linear alkylhydrogenpolysiloxane without an aryl group. [6]: The above (E) component has a BET specific surface area of ​​100 m 2 An addition-curing silicone composition characterized by being fumed silica of 1 / g or more, as described in any one of the above [1] to [5]. [7]: An addition-curing silicone composition according to any one of the above [1] to [6], 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 component (E) is 5 to 20 parts by mass per 100 parts by mass of the total of components (A) and (B). [9]: Addition-curing silicone composition, (A')(R 1 2R 2 SiO 1 / 2 ) Units and (R 1 2SiO 2 / 2 ) Unit (R 1 Each of these is independently an alkyl group or an alkenyl group, and R 2 (is an alkenyl group.) consists of a linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, (B') An organopolysiloxane resin represented by the following general formula (1), (R 3 3SiO 1 / 2 ) a (R 4 R 3 2SiO 1 / 2 ) b (R 4 R 3 SiO 2 / 2 ) c (R 3 2SiO 2 / 2 ) d (R 4 SiO 3 / 2 ) e (R 3 SiO 3 / 2 ) f (SiO 4 / 2 ) g (XO 1 / 2 ) h (1) (In the formula, R 3 Each of them is 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. (C')(R 5 HSiO 2 / 2 ) Unit (R 5 (is an alkyl group.) and a linear alkylhydrogenpolysiloxane that does not have an aryl group, (D') Platinum group metal catalyst, (E')BET specific surface area is 100m 2 Silica of / g or more: 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B'), An addition-curing silicone composition characterized by containing the following:

[10] : The 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.

[11] : A cured product characterized in that it is obtained by curing any one of the addition-curing silicone compositions from [1] to

[10] above.

[12] : The cured product of

[11] above, characterized in that the durometer type A hardness is 70 to 95.

[13] : A lens characterized by being made of the cured product of

[11] or

[12] above.

[14] : An optoelectronic device characterized in that an optical element is sealed with the cured product of

[11] or

[12] above.

[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. Addition-curing silicone composition, (A) A linear organopolysiloxane having alkenyl groups bonded to silicon atoms at both ends of the molecular chain, (B) An organopolysiloxane resin having an alkenyl group bonded to a silicon atom, (C) A linear organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, (D) Platinum group metal catalysts, (E) Silica and, It contains a sodium D-ray with a refractive index of less than 1.42 at 25°C and a shear rate of 10s at 23°C. －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 a (R １ ２ R ２ SiO １／２ ) unit and (R １ ２ SiO ２／２ ) unit (R １ each independently represents an alkyl group or an alkenyl group, and R ２ represents an alkenyl group.), which is a linear organopolysiloxane having an alkenyl group content of 0.020 mol / 100g or more. The addition-curable silicone composition according to claim 1, characterized in that:

3. The addition-curing silicone composition according to claim 1, 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) (In the formula, 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 aforementioned (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 (E) component 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 (is an alkenyl group.) consists of a linear organopolysiloxane having an alkenyl group amount of 0.020 mol / 100g or more, (B') An organopolysiloxane resin 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) (In the formula, 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. (C') (R ５ HSiO ２／２ ) Unit (R ５ (is an alkyl group.) and a linear alkylhydrogenpolysiloxane that does not have an aryl group, (D') Platinum group metal catalysts, (E') BET specific surface area is 100 m ２ Silica of 1g or more: 5 to 20 parts by mass per 100 parts by mass of the total of component (A') and component (B'), An addition-curing silicone composition characterized by containing the following:

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 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 material described in claim 11.

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