Addition curing type silicone composition, method for producing the composition, silicone cured material for light reflection material, light reflection material and optical semiconductor device

Abstract

To provide an addition curing type silicone composition having shape retainability and small viscosity change over time.SOLUTION: There is provided an addition curing type silicone composition which comprises (A) a straight-chain organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and no trialkoxysilyl groups and having a viscosity at 23°C of 500 to 100000 mPa s, (B) a specific organopolysiloxane resin, (C) an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule and no addition-reactive carbon-carbon double bonds, (D) a hydrosilylation catalyst containing a platinum group metal, (E) fumed silica and (F) (i) titanium oxide the surface of which is surface-treated with (ii) an organosilicon compound having a trialkoxysilyl group and having no hydrogen atoms bonded to silicon atoms.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an addition-curable silicone composition, a method for producing the composition, a silicone cured product for a light reflecting material, a light reflecting material, and an optical semiconductor device.

Background Art

[0002] As a method for manufacturing a light-emitting diode (hereinafter referred to as "LED"), a method called COB (Chip on Board) is generally used, in which a frame (dam material) made of a light-reflective silicone rubber and an LED chip are installed on a substrate, and after potting a sealing material, the dam material and the sealing material are cured by heating.

[0003] As the dam material, a one-component addition-curable liquid silicone rubber composition obtained by mixing fumed silica or the like into an addition-curable silicone rubber to increase the viscosity and thixotropy, and further adding titanium oxide to impart light reflectivity is widely used (Patent Document 1).

[0004] The dam material is required to have both shape retention that does not flow and maintains its shape until curing and dischargeability during dispensing, in addition to adhesiveness to the substrate.

[0005] On the other hand, in an addition-curable silicone composition containing titanium oxide, an increase in viscosity due to plasticization return derived from the titanium oxide formulation has been a problem. When the viscosity increases during storage of the composition, the dispensing workability is lost, and the performance as a dam material used for COB is impaired. For example, it is impossible to discharge from a syringe, productivity deteriorates due to a decrease in discharge speed, and the shape of the dam is defective.

[0006] Conventional dam materials have a problem in storage at room temperature where thickening becomes more prominent due to the movement to reduce energy consumption during transportation and storage, and thickening cannot be avoided even when sealed in a syringe or cartridge and stored refrigerated.

Prior Art Documents

Patent Document

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of the above circumstances, and provides an addition-curing type silicone composition having shape retention and a small change in viscosity over time, and giving a cured product excellent in light reflection performance.

Means for Solving the Problems

[0009] In order to solve the above problems, in the present invention, (A) A linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and no trialkoxysilyl group, having a viscosity at 23°C of 500 to 100,000 mPa·s: 40 to 90 parts by mass, (B) An organopolysiloxane resin represented by the following average composition formula (1): 10 to 60 parts by mass (however, the total of component (A) and component (B) is 100 parts by mass). (R 1 3SiO 1 / 2 ) a (R 1 2R 2 SiO 1 / 2 ) b (R 1 2SiO) c (R 1 R 2 SiO) d (R 1 SiO 3 / 2 ) e (R 2 SiO 3 / 2 ) f (SiO 4 / 2 ) g (1) (In the formula, R 1is an unsubstituted or halogen-substituted monovalent hydrocarbon group that does not independently contain an addition-reactive carbon-carbon double bond, and R 2 is independently an alkenyl group. a, b, c, d, e, f, and g are numbers that satisfy b + d + f > 0 and e + f + g > 0, and a + b + c + d + e + f + g = 1. ) (C) An organohydrogenpolysiloxane having hydrogen atoms bonded to at least two silicon atoms in one molecule and not having an addition-reactive carbon-carbon double bond: an amount such that the hydrogen atoms bonded to silicon atoms are 1.0 to 3.0 moles per mole of the alkenyl group in components (A) and (B), (D) A hydrosilylation catalyst containing a platinum group metal: 0.0001 to 0.1 part by mass in terms of the mass of the platinum group metal, (E) Fumed silica: 5 to 30 parts by mass, and (F) Particles whose surface of (i) titanium oxide is surface-treated with an organosilicon compound having (ii) a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom: 5 to 50 parts by mass as the mass of (i), provided is an addition-curing type silicone composition containing the same.

[0010] The addition-curing type silicone composition of the present invention has shape retention and a small change in viscosity over time, and further provides a cured product having excellent light reflection performance.

[0011] Moreover, it is preferable that the component (C) contains an organohydrogenpolysiloxane represented by the following formula (3). [Chemical formula] (In the formula, R 3 is independently a hydrogen atom, a 2-(trimethoxysilyl)ethyl group, or a 3-(trimethoxysilyl)propyl group, provided that one or more of R 3 are a 2-(trimethoxysilyl)ethyl group or a 3-(trimethoxysilyl)propyl group, and R 3Two or more of them are hydrogen atoms. p is an integer from 0 to 50, q is an integer from 1 to 50, and the arrangement of the siloxane units in parentheses is arbitrary.)

[0012] Such an addition-curing silicone composition has better shape retention and adhesion.

[0013] Furthermore, it is preferable that the organosilicon compound in the component (F) is an organopolysiloxane represented by the following formula (4). [Chemical formula] (In the formula, R 4 is independently a methyl group or a methoxy group, n is an integer from 0 to 10, m is an integer from 1 to 50, and the arrangement of the siloxane units in parentheses is arbitrary.)

[0014] Such an addition-curing silicone composition can further suppress the volatilization of the organosilicon compound.

[0015] The present invention provides a method for producing the above addition-curing silicone composition, which includes a step of heat-treating a composition containing (i) titanium oxide and (ii) an organosilicon compound having a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom at 100 to 180 °C.

[0016] The composition obtained by such a production method has shape retention and a small change in viscosity over time, and further provides a cured product with excellent light reflection performance.

[0017] The present invention also provides a silicone cured product for a light reflector, which is a cured product of the above addition-curing silicone composition.

[0018] The silicone cured product for a light reflector preferably has a reflectance of 95% or more for light with a wavelength of 450 nm at a thickness of 2 mm.

[0019] Such a silicone cured product for a light reflecting material has excellent light reflection performance.

[0020] The present invention provides a light reflecting material comprising the above silicone cured product for a light reflecting material.

[0021] Such a light reflecting material can be suitably used, for example, for a light semiconductor device such as an LED, particularly as a dam material.

[0022] Furthermore, the present invention provides a light semiconductor device including the above light reflecting material.

[0023] Such a light semiconductor device has high light extraction efficiency.

Effects of the Invention

[0024] The addition-curing type silicone composition of the present invention is an addition-curing type silicone composition having shape retention and a small change in viscosity over time, and is particularly useful as a dam material for a light semiconductor device in the COB method because it gives a cured product having excellent light reflection performance.

Embodiments for Carrying Out the Invention

[0025] As described above, there has been a demand for the development of an addition-curing type silicone composition having shape retention, a small change in viscosity over time, excellent storage stability, and giving a cured product having excellent light reflection performance.

[0026] As a result of intensive studies on the above problems, the present inventor has found that an addition-curing type silicone composition containing the following components (A) to (F) can solve the above problems and is suitable as a dam material for a light semiconductor device, and has completed the present invention.

[0027] That is, the present invention is (A) A linear organopolysiloxane having at least 2 alkenyl groups bonded to silicon atoms in one molecule and no trialkoxysilyl group, with a viscosity at 23°C of 500 to 100,000 mPa·s: 40 to 90 parts by mass, (B) An organopolysiloxane resin represented by the following average composition formula (1): 10 to 60 parts by mass (however, the total of component (A) and component (B) is 100 parts by mass.), (R 1 3SiO 1 / 2 ) a (R 1 2R 2 SiO 1 / 2 ) b (R 1 2SiO) c (R 1 R 2 SiO) d (R 1 SiO 3 / 2 ) e (R 2 SiO 3 / 2 ) f (SiO 4 / 2 ) g (1) (In the formula, R 1 is independently an unsubstituted or halogen-substituted monovalent hydrocarbon group that does not contain an addition-reactive carbon-carbon double bond, and R 2 is independently an alkenyl group. a, b, c, d, e, f, and g are numbers that satisfy b + d + f > 0 and e + f + g > 0, and a + b + c + d + e + f + g = 1.) (C) An organohydrogenpolysiloxane having at least 2 hydrogen atoms bonded to silicon atoms in one molecule and no addition-reactive carbon-carbon double bond: an amount such that the hydrogen atoms bonded to silicon atoms are 1.0 to 3.0 moles per mole of the alkenyl groups in component (A) and component (B), (D) A hydrosilylation catalyst containing a platinum group metal: 0.0001 to 0.1 part by mass in terms of the mass of the platinum group metal, (E) Fumed silica: 5 to 30 parts by mass, and (F)(i) Particles whose surface of titanium oxide is surface-treated with an organosilicon compound having (ii) a trialkoxysilyl group and no hydrogen atom bonded to a silicon atom: 5 to 50 parts by mass as the mass of (i), which is an addition-curing silicone composition containing the same.

[0028] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. In this specification, the viscosity is the value at 23°C measured at a rotational speed of 4 rpm using a BH-type rotational viscometer.

[0029] [Addition-curing silicone composition] Hereinafter, each component will be described in detail. [Component (A)] Component (A) is a linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and no trialkoxysilyl group, and having a viscosity at 23°C of 500 to 100,000 mPa·s.

[0030] The number of alkenyl groups bonded to silicon atoms contained in one molecule is at least two, preferably 2 to 20, more preferably 2 to 5. If it is less than two, the hardness of the cured product becomes insufficient.

[0031] The bonding position of the alkenyl group in the linear organopolysiloxane of component (A) may be at the molecular chain end, at the non-terminal of the molecular chain, or both, but it is preferable that the alkenyl group is bonded to the silicon atoms at both ends of the molecular chain.

[0032] The viscosity of component (A) at 23°C is in the range of 500 to 100,000 mPa·s from the viewpoint that the physical properties of the resulting silicone rubber are good and the discharge stability of the composition. If it exceeds 100,000 mPa·s, the composition becomes highly viscous and the dischargeability decreases. If it is less than 500 mPa·s, the rubber physical properties after curing are impaired and the reliability decreases.

[0033] (A) component is preferably represented by the following formula (2). (R 1 2R 2 SiO 1 / 2 )2(R 1 2SiO) h (2)

[0034] In the above formula (2), R 1 is independently an unsubstituted or halogen-substituted monovalent hydrocarbon group that does not contain an addition-reactive carbon-carbon double bond. For example, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc. Usually, unsubstituted or halogen-substituted monovalent hydrocarbon groups having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, can be mentioned. Preferably, it is a methyl group or a phenyl group, and particularly preferably a methyl group.

[0035] In the above formula (2), R 2 is independently an alkenyl group. For example, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, etc., usually having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms. From the perspective of raw material supply, it is particularly preferably a vinyl group.

[0036] In the above formula (2), h may be an integer such that the viscosity of the (A) component is 500 to 100,000 mPa·s, but 100 to 500 is preferred, and 200 to 400 is more preferred. Also, the (A) component may be used alone or in combination of two or more. When the (A) component is used as a mixture of two or more, the mixing ratio may be adjusted so that the viscosity after mixing is within the above range.

[0037] [(B) component] (B) component is an organopolysiloxane resin represented by the following average composition formula (1), has a branched structure, and functions as a reinforcing component of silicone rubber. (R1 3SiO 1 / 2 ) a (R 1 2R 2 SiO 1 / 2 ) b (R 1 2SiO) c (R 1 R 2 SiO) d (R 1 SiO 3 / 2 ) e (R 2 SiO 3 / 2 ) f (SiO 4 / 2 ) g (1) (wherein, R 1 is independently an unsubstituted or halogen-substituted monovalent hydrocarbon group that does not contain an addition-reactive carbon-carbon double bond, and R 2 is independently an alkenyl group. a, b, c, d, e, f, and g are numbers satisfying b + d + f > 0 and e + f + g > 0, and a + b + c + d + e + f + g = 1.)

[0038] In the above formula (1), examples of the monovalent hydrocarbon group of R 1 include the same groups as those exemplified in the above formula (2), preferably a methyl group and a phenyl group, and particularly preferably a methyl group.)

[0039] In the above formula (1), examples of the alkenyl group of R 2 include the same groups as those exemplified in the above formula (2), preferably a vinyl group.)

[0040] In the above formula (1), a is preferably a number from 0 to 0.65, b is preferably a number from 0 to 0.65, c is preferably a number from 0 to 0.5, d is preferably a number from 0 to 0.5, e is preferably a number from 0 to 0.8, f is preferably a number from 0 to 0.8, and g is preferably a number from 0 to 0.6. Also, b + d + f is preferably a number from 0.01 to 0.30, particularly preferably a number from 0.05 to 0.10, and e + f + g is preferably a number from 0.1 to 0.8, particularly preferably a number from 0.2 to 0.6.)

[0041] Specific examples of the component (B) include, for example, the following, but are not limited thereto.) [(CH3)3SiO 1 / 2 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 0.06 [SiO 4 / 2 0.54 、 [(CH3)3SiO 1 / 2 0.48 [(CH2=CH)(CH3)SiO 2 / 2 0.08 [SiO 4 / 2 0.44 [(CH3)3SiO 1 / 2 0.40 [(CH2=CH)(CH3)SiO 2 / 2 0.10 [CH3SiO 3 / 2 0.50 [(CH3)3SiO 1 / 2 0.20 [(CH2=CH)(CH3)2SiO 1 / 2 0.20 [CH3SiO 3 / 2 0.30 [SiO 4 / 2 0.30

[0042] (Component (B) may be used alone or in combination of two or more.)

[0043] (The compounding amount of component (B) is 10 to 60 parts by mass, preferably 15 to 30 parts by mass, based on 100 parts by mass in total of component (A) and component (B). When the compounding amount of component (B) is less than 10 parts by mass based on 100 parts by mass in total of component (A) and component (B), it is difficult to obtain a sufficient reinforcing effect. Further, when the compounding amount exceeds 60 parts by mass, the dischargeability deteriorates due to an increase in the viscosity of the composition.)

[0044] [(Component (C))] ​​​​​​​​​​​​​The (C) component is an organohydropolysiloxane having hydrogen atoms bonded to at least two silicon atoms in one molecule (i.e., Si-H groups) and having no addition-reactive carbon-carbon double bonds, and undergoes a hydrosilylation reaction with the alkenyl groups of the (A) and (B) components to act as a crosslinking agent.

[0045] The molecular structure of the organohydropolysiloxane of the (C) component is not particularly limited, and examples include linear, cyclic, branched-chain, three-dimensional network structure (resin-like), etc., and linear or cyclic is preferred.

[0046] The bonding position of the silicon atom-bonded hydrogen atom in the organohydropolysiloxane molecule of the (C) component may be at the molecular chain end, at a non-terminal position of the molecular chain, or both.

[0047] The organohydropolysiloxane of the (C) component has at least 2, preferably 3 to 40 Si-H groups in one molecule.

[0048] In the (C) component, the content of the silicon atom-bonded hydrogen atom is preferably 0.001 to 1 mol, particularly preferably 0.005 to 0.5 mol, per 100 g of the (C) component.

[0049] In the organohydropolysiloxane molecule of the (C) component, the silicon atom-bonded hydrocarbon groups other than the above silicon atom-bonded hydrogen atoms are not particularly limited, and examples include unsubstituted or substituted monovalent hydrocarbon groups not containing addition-reactive carbon-carbon double bonds, such as alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, and substituted alkyl groups such as 3-glycidoxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group, etc. Preferred are a methyl group and a phenyl group, and particularly preferred is a methyl group.

[0050] (C) component may have an alkoxy group bonded to one or more silicon atoms in one molecule. In this case, it is possible to improve the shape retention and adhesiveness of the addition-curing silicone composition of the present invention. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc., and a methoxy group is preferable. Further, the alkoxysilyl group may be bonded to a silicon atom via an alkylene group. Specific examples of such a group include a 2-(trimethoxysilyl)ethyl group, a 3-(trimethoxysilyl)propyl group, etc.

[0051] (C) component preferably contains an organohydrogenpolysiloxane represented by the following formula (3). [Chemical formula] (In the formula, R 3 is independently a hydrogen atom, a 2-(trimethoxysilyl)ethyl group or a 3-(trimethoxysilyl)propyl group, provided that one or more of R 3 are a 2-(trimethoxysilyl)ethyl group or a 3-(trimethoxysilyl)propyl group, and two or more of R 3 are hydrogen atoms. p is an integer from 0 to 50, q is an integer from 1 to 50, and the arrangement of the siloxane units in parentheses is arbitrary.)

[0052] In the above formula (3), if p is 0 or more and 50 or less, it is preferable for improving the curability of the composition and the rubber physical properties of the cured product. If q is 1 or more and 50 or less, it is preferable for improving the shape retention and adhesiveness of the composition.

[0053] In the organohydrogenpolysiloxane represented by the above formula (3), the 2-(trimethoxysilyl)ethyl group or 3-(trimethoxysilyl)propyl group bonded to the silicon atom may be bonded to either the terminal or the side chain of the molecular chain, but it is preferable that the alkoxy group is bonded only to the terminal of the molecular chain.

[0054] In the above formula (3), p is preferably from 0 to 20, more preferably from 1 to 10, q is preferably from 1 to 30, and more preferably from 2 to 10.

[0055] The organohydrogenpolysiloxane represented by the above formula (3) can be obtained, for example, by subjecting a dimethylsiloxane·hydrogenmethylsiloxane copolymer blocked with dimethylsiloxy groups at both ends of the molecular chain and vinyltrimethoxysilane or allyltrimethoxysilane to a hydrosilylation reaction in the presence of a platinum group metal catalyst.

[0056] Specific examples of the component (C) include, but are not limited to, organohydrogenpolysiloxanes represented by the following formula.

Chemical formula

[0057] The organohydrogenpolysiloxane of the component (C) may be used alone or in combination of two or more.

[0058] The viscosity of the component (C) at 25°C preferably satisfies the range of 0.1 to 5,000 mPa·s, more preferably 0.5 to 1,000 mPa·s, and particularly preferably 2 to 200 mPa·s, and is preferably in the range of being liquid at 23°C, because the workability of the composition and the optical and mechanical properties of the cured product are more excellent. When such a viscosity is satisfied, the number of silicon atoms (or degree of polymerization) in one molecule of the organohydrogenpolysiloxane is usually from 2 to 1,000, preferably from 3 to 200, and more preferably from 4 to 50.

[0059] The blending amount of component (C) is an amount such that the hydrogen atoms bonded to silicon atoms are 1.0 to 3.0 moles, preferably 1.5 to 2.5 moles, per mole of alkenyl groups in components (A) and (B). If it is less than 1.0 mole, the adhesive strength of the cured product may decrease. If it exceeds 3.0 moles, the hardness of the cured product may decrease and the rubber strength may be inferior.

[0060] [Component (D)] The platinum group metal-based hydrosilylation catalyst of component (D) is not particularly limited as long as it promotes the hydrosilylation reaction between the alkenyl groups in components (A) and (B) and the Si-H groups in component (C). Specific examples thereof 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. Among them, platinum-based compounds are preferred, and coordination compounds of chloroplatinic acid with vinylsiloxanes are particularly preferred.

[0061] Also, as component (D), a substance that is inert under light-shielding conditions and changes into an active platinum catalyst by radicals generated by light irradiation or decomposition of an organic peroxide described later may be used. Specific examples of such component (D) include, but are not limited to, cyclopentadienyltrimethylplatinum and derivatives thereof in which the cyclopentadienyl group is modified, and bis(acetylacetonato)platinum and derivatives thereof in which the acetylacetonato group is modified.

[0062] Component (D) may be used alone or in combination of two or more.

[0063] (D) component's blending amount only needs to be an effective amount as a hydrosilylation catalyst, but it is 0.0001 to 0.1 parts by mass in terms of the mass conversion of the platinum group metal with respect to 100 parts by mass in total of (A) component and (B) component, preferably 0.0003 to 0.01 parts by mass. When such a range is satisfied, the reaction rate of the addition reaction becomes appropriate, and a cured product having high strength can be obtained.

[0064] [(E) component] (E) component is fumed silica, which is a component that imparts appropriate dischargeability and shape retention to the addition-curing type silicone composition of the present invention and improves the strength of the cured product. From the viewpoint of shape retention, the fumed silica of the present invention preferably has a specific surface area of 150 to 350 m 2 / g by the BET method.

[0065] In addition, since the dispersibility with respect to the addition-curing type silicone composition of the present invention is improved, it is preferable that the (E) component is surface-treated. For example, it is preferable to treat the surface hydroxyl groups with a silicon compound such as dimethyldichlorosilane or hexamethyldisilazane. Particularly preferably, fumed silica surface-treated with hexamethyldisilazane is preferred.

[0066] Examples of fumed silica include Musil120A (manufactured by Shin-Etsu Chemical Co., Ltd., treated with hexamethyldisilazane, BET 200 m 2 / g), Musil130A (manufactured by Shin-Etsu Chemical Co., Ltd., treated with hexamethyldisilazane, BET 300 m 2 / g), NSX-200 (manufactured by Nippon Aerosil Co., Ltd., treated with hexamethyldisilazane, BET 200 m 2 / g), and Rheoseal DM30S (manufactured by Tokuyama Corporation, treated with dimethyldichlorosilane), etc.

[0067] The content of component (E) is 5 to 30 parts by mass, preferably in the range of 10 to 20 parts by mass, based on 100 parts by mass in total of components (A) and (B). If it is less than 5 parts by mass, the shape retention after discharging the addition-curing type silicone composition of the present invention is poor, and the height of the dam material may be insufficient. If it exceeds 30 parts by mass, the dischargeability of the composition may deteriorate.

[0068] [Component (F)] Component (F) is particles obtained by surface-treating titanium oxide with an organosilicon compound having (i) a surface of titanium oxide and (ii) a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom, and is a component that imparts light reflection performance to the addition-curing type silicone composition of the present invention.

[0069] When the surface treatment of titanium oxide with the organosilicon compound is not performed, the viscosity of the addition-curing type silicone composition of the present invention changes greatly over time, and problems such as a decrease in productivity due to a decrease in the dischargeability of the composition and poor formation of the dam material may occur.

[0070] The particle size of the (i) titanium oxide is not particularly limited, but from the viewpoints of dispersibility and reflectance, it preferably has an average particle size of 0.1 to 0.5 μm in the measurement of particle size distribution by the laser light diffraction method.

[0071] The crystal form of titanium oxide is classified into anatase, rutile, and brookite, but it is preferable to use the rutile type in which the thermal transition is most stable. Also, surface treatment may be performed with a surface treatment agent other than the organosilicon compound and metals such as silicon, aluminum, and zirconium and their oxides.

[0072] As such titanium oxide, commercially available products may be used. Specific examples include R-820 (rutile type, average particle size 0.26 μm, Al / Si / Zn surface treatment), CR-60 (rutile type, average particle size 0.21 μm, Al surface treatment), PF-691 (rutile type, average particle size 0.21 μm, polyol surface treatment), etc. manufactured by Ishihara Sangyo Co., Ltd.

[0073] (i) The blending amount of titanium oxide is 5 to 50 parts by mass, preferably in the range of 10 to 30 parts by mass, based on 100 parts by mass in total of components (A) and (B). If it is less than 5 parts by mass, the light reflectivity of the cured product may be insufficient. If it exceeds 50 parts by mass, the dischargeability and storage stability of the composition may decrease.

[0074] The above-mentioned (ii) organosilicon compound having a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom is distinguished from components (A) and (B) in that it has a trialkoxysilyl group, and is distinguished from component (C) in that it does not have a hydrogen atom bonded to a silicon atom.

[0075] Examples of the trialkoxysilyl group include a trimethoxysilyl group, a triethoxysilyl group, and a tripropoxysilyl group, and a trimethoxysilyl group is particularly preferred.

[0076] The group bonded to the silicon atom other than the alkoxy group is not particularly limited, and examples thereof include an unsubstituted or substituted monovalent hydrocarbon group, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, and a heptyl group; an alkenyl group such as a vinyl group, an allyl group, and a 3-butenyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; an aralkyl group such as a benzyl group and a phenethyl group; a halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group, and a 3,3,3-trifluoropropyl group, and a substituted alkyl group such as a 3-glycidoxypropyl group and a 2-(3,4-epoxycyclohexyl)ethyl group. A methyl group, a vinyl group, and a 3-glycidoxypropyl group are preferred.

[0077] In the addition-curing type silicone composition of the present invention, the organosilicon compound in component (F) is preferably an organopolysiloxane represented by the following formula (4). [Chemical formula] (In the formula, R 4is independently a methyl group or a methoxy group, n is an integer from 0 to 10, m is an integer from 1 to 50, and the arrangement of the bracketed siloxane units is arbitrary.)

[0078] In the addition-curing silicone composition of the present invention, if the organosilicon compound component in the (F) component is the organopolysiloxane represented by the above formula (4), the volatilization of the organosilicon compound can be further suppressed.

[0079] Specific examples of such an organosilicon compound having a (ii) trialkoxysilyl group and no hydrogen atom bonded to a silicon atom include, but are not limited to, those represented by the following formula.

Chemical formula

[0080] The amount of the organosilicon compound having a (ii) trialkoxysilyl group and no hydrogen atom bonded to a silicon atom used is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, based on the mass of (i) titanium oxide, from the viewpoint of suppressing the dispersibility of the (F) component and the increase in viscosity over time of the composition.

[0081] The (F) component can be obtained, for example, by heat-treating a composition containing the above (i) titanium oxide and the above (ii) organosilicon compound having a trialkoxysilyl group and no hydrogen atom bonded to a silicon atom at 100 to 180°C. When the heat-treatment temperature is in the range of 100 to 180°C, it is preferable because the hydrolysis and condensation reaction of the trialkoxysilyl group on the surface of titanium oxide proceeds efficiently.

[0082] The temperature during the heat treatment is preferably 120 to 160 °C, the heat treatment time is preferably 30 minutes to 5 hours, and more preferably 1 to 3 hours. Further, in order to efficiently remove the alcohol and water by-produced by the hydrolysis and condensation reaction of the alkoxy group on the titanium oxide surface and promote the reaction, it is preferable to perform the heat treatment under reduced pressure conditions.

[0083] (F) component may be used alone or in combination of two or more.

[0084] <Other components> To the addition-curing type silicone composition of the present invention, components such as a reaction inhibitor, an organic peroxide, and an adhesion improver may be added according to the purpose.

[0085] Examples of the reaction inhibitor include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; sulfur-containing compounds; acetylene compounds; hydroperoxy compounds; maleic acid derivatives; and acetylene alcohol-based reaction control agents such as 1-ethynyl-1-cyclohexanol, 3-methyl-1-tridecyn-3-ol, and 3,5-dimethyl-1-hexyn-3-ol. Among them, acetylene alcohol-based reaction control agents are preferred.

[0086] Since the degree of the curing inhibition effect by the reaction inhibitor varies greatly depending on the chemical structure of the reaction inhibitor, it is preferable to adjust the blending amount of the reaction inhibitor to an optimal amount for each reaction inhibitor used. Usually, 0.001 to 5 parts by mass is preferable with respect to 100 parts by mass in total of the (A) component and the (B) component. If the blending amount is 0.001 part by mass or more, sufficient long-term storage stability of the composition at room temperature can be obtained. If the blending amount is 5 parts by mass or less, there is no risk of inhibiting the curing of the composition.

[0087] Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, o-methylbenzoyl peroxide, p-methylbenzoyl peroxide, dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,3-trimethylcyclohexane, 1,6-bis(t-butylperoxycarbonyloxy)hexane, and di(4-methylbenzoylperoxy)hexamethylene biscarbonate.

[0088] The addition amount of the organic peroxide is preferably 0.01 to 5 parts by mass, particularly preferably 0.05 to 3 parts by mass, based on 100 parts by mass in total of the components (A) and (B). Within such a range, further improvement in resin strength can be achieved. These can be used alone or in combination of two or more.

[0089] As the adhesion improver, from the viewpoint of imparting self-adhesion to the addition reaction curable composition of the present invention, organosilicon compounds such as silanes and siloxanes containing a functional group for imparting adhesion, and non-silicone organic compounds are used.

[0090] Specific examples of the functional group for imparting adhesion include alkenyl groups such as vinyl group and allyl group, or a hydrogen atom; an epoxy group bonded through a carbon atom (for example, 3-glycidoxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group, etc.), an acryloxy group (for example, 3-acryloxypropyl group, etc.), or a methacryloxy group (for example, 3-methacryloxypropyl group, etc.).

[0091] Examples of the non-silicone organic compound include allyl esters of organic acids, epoxy ring-opening catalysts, organic titanium compounds, organic zirconium compounds, and organic aluminum compounds.

[0092] [Method for Producing Addition-Curing Type Silicone Composition] The addition-curing silicone composition of the present invention may be produced by mixing components (A) to (E), component (F) which consists of (i) titanium oxide and (ii) an organosilicon compound having a trialkoxysilyl group and no hydrogen atom bonded to a silicon atom, and other components according to the purpose, and then heat-treating at 100 to 180°C. Alternatively, after producing component (F) in advance, it may be produced by mixing this with components (A) to (E) and other components added according to the purpose. In the latter case, component (F) is produced by heat-treating (i) titanium oxide and (ii) an organosilicon compound having a trialkoxysilyl group and no hydrogen atom bonded to a silicon atom at 100 to 180°C in advance, and the produced component (F) is mixed with components (A) to (E) and other components added according to the purpose to produce the addition-curing silicone composition of the present invention.

[0093] [Silicone cured product for light reflector] By curing the addition-curing silicone composition of the present invention, a white silicone cured product for a light reflector can be obtained. Since the addition-curing silicone composition of the present invention has good dischargeability, a light reflector can be formed by discharging it with a dispensing device and then curing it. The curing conditions of the addition-curing silicone composition of the present invention are not particularly limited, but usually, it is preferably 80 to 200°C, more preferably 100 to 150°C for 30 minutes to 4 hours, and even more preferably 30 minutes to 1 hour.

[0094] The hardness (durometer type A hardness) of a sheet cured under the conditions of 150°C for 1 hour of the addition-curing silicone composition of the present invention is preferably in the range of 50 to 70. If the type A hardness is 50 or more, it has sufficient rubber strength as a dam material, and if it is 70 or less, it has flexibility, so defects such as cracks can be suppressed under actual use conditions.

[0095] Regarding the light reflection performance of the silicone cured product for the light reflecting material of the present invention, the relative light reflectance (light reflectance) at a wavelength of 450 nm when an aluminum oxide plate is used as a blank (100%) is measured and evaluated. Specifically, the silicone composition for the light reflecting material of the present invention is cured under the conditions of 150 °C for 1 hour to produce a silicone cured product for the light reflecting material of the present invention with a thickness of 2 mm, and the relative light reflectance (light reflectance) at a wavelength of 450 nm of this cured product with a thickness of 2 mm is measured. A cured product with a light reflectance of 95% or more is evaluated as a preferable cured product.

[0096] [Light reflecting material] The light reflecting material composed of the silicone cured product for the light reflecting material of the present invention can be suitably used, for example, for light semiconductor devices such as LEDs, particularly as a dam material.

[0097] [Light semiconductor device] Furthermore, the present invention provides a light semiconductor device having the above light reflecting material.

[0098] As described above, the addition-curing type silicone composition of the present invention provides a silicone cured product for a light reflecting material with excellent light reflection performance. Therefore, a light semiconductor device such as a white LED using the light reflecting material of the present invention can maintain a high light extraction efficiency over a long period.

[0099] As a method of using the addition-curing type silicone composition of the present invention, although it is not particularly limited, for example, the addition-curing type silicone composition of the present invention is discharged by a dispensing device around an LED element disposed on a substrate such as an FRP resin (fiber reinforced plastic) using an epoxy resin, and a frame is formed in a shape such as a square as a dam material. The discharged composition is cured by a heating furnace, and a resin (epoxy resin, silicone resin, etc.) for sealing the LED element inside the dam material is potted and cured for sealing.

[0100] At this time, if the viscosity of the dam material increases, defects such as wire drawing may occur during discharge, resulting in a decrease in productivity. In addition, the dam material cannot be formed properly, which has an adverse effect on optical properties such as light reflectivity. The addition-curing type silicone composition of the present invention can suppress the increase in viscosity during storage, so that productivity can be improved.

Examples

[0101] Hereinafter, the present invention will be specifically described using examples and comparative examples, but the present invention is not limited thereto.

[0102] In the following, the viscosity at 23 ° C is the measured value by a rotational viscometer BH type at 4 rpm. The meanings of the abbreviations of each siloxane unit are as follows. M: (CH3)3SiO 1 / 2 M Vi : (CH2=CH)(CH3)2SiO 1 / 2 M H : H(CH3)2SiO 1 / 2 M Si :

Chemical formula

[0103] [Examples 1 to 6, Comparative Examples 1 to 4] The following components were mixed in the blending amounts shown in Tables 1 and 2 to prepare an addition-curing type silicone composition. The numerical values of each component in Table 1 represent parts by mass.

[0104] That is, first, using a 5-liter gate mixer (manufactured by Inoue Seisakusho Co., Ltd., trade name: 5-liter planetary mixer), components (A), (B), (F-i), and (F-ii) were mixed at 25°C for 1 hour, and then heat-treated at 150°C under a reduced pressure of 0.1 MPa for 2 hours. Next, component (E) was added at 25°C and mixed for 30 minutes. Subsequently, components (D) and (G) (in Examples 5 and 6 and Comparative Example 4, component (H) was further added) were added and mixed at 25°C for 30 minutes. Finally, component (C) was added and mixed at 25°C under a reduced pressure (30 mmHg) environment for 30 minutes to obtain an addition-curable silicone composition.

[0105] (A) component: (A-1) M Vi 2D 216 represented by, a linear organopolysiloxane with a vinyl group content of 0.012 mol / 100 g and a viscosity of 1,000 mPa·s at 23°C (A-2) M Vi 2D 388 represented by, a linear organopolysiloxane with a vinyl group content of 0.007 mol / 100 g and a viscosity of 5,000 mPa·s at 23°C

[0106] (B) component: (B-1) with an average structural unit ratio of M 0.4 M Vi 0.06 Q 0.54 represented by, an organopolysiloxane resin that is solid at 23°C with a vinyl group content of 0.085 mol / 100 g (B-2) with an average structural unit ratio of M 0.48 D Vi 0.08 Q 0.44 represented by, an organopolysiloxane resin that is solid at 23°C with a vinyl group content of 0.11 mol / 100 g

[0107] (C) component: (C-1) M2D H represented by 8, an organohydropolysiloxane with an SiH content of 0.012 mol / g (C-2) M H M Si D2DH The organohydrogenpolysiloxane represented by 7 (C-3) M2D H 38 The organohydrogenpolysiloxane represented by (C-4) The organohydrogenpolysiloxane represented by the following structural formula [Chemical formula]

[0108] (D) Component: (D-1) A hydrosilylation catalyst obtained by diluting the reaction product of chloroplatinic acid and 1,3-divinyltetramethyldisiloxane with dimethylpolysiloxane having a viscosity of 600 mPa·s so that the platinum content is 1% by mass (D-2) A hydrosilylation catalyst obtained by diluting trimethyl(methylcyclopentadienyl)platinum complex with dimethylpolysiloxane having a viscosity of 600 mPa·s so that the platinum content is 0.5% by mass

[0109] (E) Component: (E-1) Surface-hydrophobized fumed silica with a BET specific surface area of 200 m 2 / g (Musil120A manufactured by Shin-Etsu Chemical Co., Ltd.)

[0110] (F-i) Component: (F-i-1) Rutile-type titanium oxide with an average particle diameter of 0.21 μm and an Al-treated surface (CR-60 manufactured by Ishihara Sangyo Co., Ltd.) (F-i-2) Rutile-type titanium oxide with an average particle diameter of 0.21 μm and a polyol-treated surface (PF-691 manufactured by Ishihara Sangyo Co., Ltd.)

[0111] (F-ii) Component: (F-ii-1) The organopolysiloxane represented by the following formula (viscosity 31 mPa·s) [Chemical formula] (F-ii-2) The organopolysiloxane represented by the following formula (viscosity 18 mPa·s) [Chemical formula] (In the formula, the order of arrangement of the siloxane units with parentheses is indefinite.) (F-ii-3) 3-Glycidoxypropyltrimethoxysilane

[0112] (Component (G): Reaction controller) (G-1) 1-Ethynyl-1-cyclohexanol

[0113] (Component (H): Peroxide) (H-1) 1,6-Bis(t-butylperoxycarbonyloxy)hexane (containing 30% aliphatic plasticizer) (Kaylene 6-70 manufactured by Chemical Nuon Co., Ltd.)

[0114]

Table 1

[0115]

Table 2

[0116] The following evaluations were performed on the addition-curing type silicone compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 4, and the results are shown in Table 3.

[0117] [Viscosity and viscosity increase rate] For each addition-curing type silicone composition immediately after production, the viscosity was measured at a rotational speed of 4 rpm using rotor No. 7 of a BH type viscometer (manufactured by Toki Sangyo Co., Ltd.). Then, after each composition was allowed to stand at 40 °C for 7 days, the viscosity was measured again, and the viscosity increase rate was calculated according to the following formula. Viscosity increase rate (%) = (Viscosity after 7 days - Viscosity immediately after production) / Viscosity immediately after production × 100 A smaller viscosity increase rate indicates better storage stability. If the viscosity increase rate is less than 25%, it can be evaluated that the one-component addition-curing type silicone composition has sufficient storage stability.

[0118] [Slump] Based on JIS A 1439:2022, each addition-curing silicone composition was filled into the groove of a stainless-steel grooved container (width 20 mm × depth 10 mm × length 200 mm) to prepare test specimens. After preparation, the test specimens were immediately suspended vertically and left standing at 23°C for 30 minutes. The distance from the lower end of the groove portion of the grooved container to the tip where the sample of each test specimen hung down was measured. If it was less than 5 mm, it was marked as ○, and if it was 5 mm or more, it was marked as ×, and the shape retention of the addition-curing silicone composition of the present invention was evaluated.

[0119] [Hardness] Each addition-curing silicone composition was cured under the conditions of 150°C for 1 hour, and the measurement was carried out based on JIS K 6249:2003. If the hardness (durometer type A hardness) was between 50 and 70, it was evaluated as having good rubber physical properties.

[0120] [Light reflectance] Each composition was cured under the conditions of 150°C for 1 hour, and a cured product of the addition-curing silicone composition of the present invention with a thickness of 2 mm was prepared. Using a spectrophotometer U-3310 manufactured by Hitachi, Ltd. and an attachment with a Φ60 integrating sphere, the relative light reflectance at a wavelength of 450 nm was measured for the obtained cured product with an aluminum oxide plate as a blank (100%).

[0121]

Table 3

[0122] As shown in Table 3, the addition-curing silicone compositions of Examples 1 to 6 had a small slump value, were excellent in shape retention as a dam material, and the viscosity increase rate after storage at 40°C for 7 days was in the range of less than 25%, showing excellent storage stability. Also, the hardness and light reflectance of the obtained cured products were good.

[0123] On the other hand, in Comparative Example 3 that did not use the (F-i) and (F-ii) components constituting the (F) component of the present invention, since it did not contain titanium oxide, the light reflectivity was insufficient. Further, in Comparative Examples 1, 2, and 4 that did not use the (F-ii) component corresponding to an organosilicon compound having a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom, since the surface of titanium oxide was not surface-treated with the (F-ii) component, the viscosity increased remarkably after storage at 40 °C for 7 days.

[0124] As described above, according to the present invention, it was found that an addition-curable silicone composition having shape retention, in which the change in viscosity over time is small, the storage stability is excellent, and a cured product having excellent light reflection performance can be provided. Further, thus, since the cured product of the addition-curable silicone composition of the present invention has a small change in viscosity over time, excellent storage stability, and excellent light reflection performance, it was found that it can provide a light reflection material and is suitably used as a dam material for light semiconductor devices such as LEDs.

[0125] This specification includes the following aspects. [1]: (A) A linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and not having a trialkoxysilyl group, having a viscosity at 23 °C of 500 to 100,000 mPa·s: 40 to 90 parts by mass, (B) An organopolysiloxane resin represented by the following average composition formula (1): 10 to 60 parts by mass (however, the total of the (A) component and the (B) component is 100 parts by mass).), (R 1 3SiO 1 / 2 ) a (R 1 2R 2 SiO 1 / 2 ) b (R 1 2SiO) c (R 1 R 2 SiO) d (R 1 SiO 3 / 2 ) e (R 2 SiO3 / 2 ) f (SiO 4 / 2 ) g (1) (wherein R 1 is independently an unsubstituted or halogen-substituted monovalent hydrocarbon group that does not contain an addition-reactive carbon-carbon double bond, and R 2 is independently an alkenyl group. a, b, c, d, e, f, and g are numbers that satisfy b + d + f > 0 and e + f + g > 0, and a + b + c + d + e + f + g = 1.) (C) An organohydrogenpolysiloxane having hydrogen atoms bonded to at least two silicon atoms in one molecule and no addition-reactive carbon-carbon double bond: an amount such that the hydrogen atoms bonded to silicon atoms are 1.0 to 3.0 moles per mole of the alkenyl groups in components (A) and (B), (D) A hydrosilylation catalyst containing a platinum group metal: 0.0001 to 0.1 part by mass in terms of the mass of the platinum group metal, (E) Fumed silica: 5 to 30 parts by mass, and (F) Particles whose surface of titanium oxide is surface-treated with an organosilicon compound having (i) a trialkoxysilyl group and (ii) no hydrogen atom bonded to a silicon atom: 5 to 50 parts by mass as the mass of (i), characterized by containing [2]: The addition-curing type silicone composition according to [1] above, wherein the component (C) contains an organohydrogenpolysiloxane represented by the following formula (3).

Chemical formula

[0126] Note that the present invention is not limited to the above embodiments. The above embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Claims

1. A linear organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and not having a trialkoxysilyl group, with a viscosity at 23°C of 500 to 100,000 mPa·s: 40 to 90 parts by mass, An organopolysiloxane resin represented by the following average composition formula (1): 10 to 60 parts by mass (however, the total of component (A) and component (B) is 100 parts by mass.), (R １ ３ SiO １／２ ) ａ (R １ ２ R ２ SiO １／２ ) ｂ (R １ ２ SiO) ｃ (R １ R ２ SiO) ｄ (R １ SiO ３／２ ) ｅ (R ２ SiO ３／２ ) ｆ (SiO ４／２ ) ｇ (1) (In the formula, R １ is an unsubstituted or halogen-substituted monovalent hydrocarbon group that independently does not contain an addition-reactive carbon-carbon double bond, and R ２ is independently an alkenyl group. a, b, c, d, e, f, and g are numbers that satisfy b + d + f > 0 and e + f + g > 0, and a + b + c + d + e + f + g = 1.) An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule and not having an addition-reactive carbon-carbon double bond: an amount such that the hydrogen atoms bonded to silicon atoms are 1.0 to 3.0 moles per mole of the alkenyl groups in component (A) and component (B), A hydrosilylation catalyst containing a platinum group metal: 0.0001 to 0.1 parts by mass in terms of the mass of the platinum group metal, Fumed silica: 5 to 30 parts by mass, and Particles whose surface of titanium oxide is surface-treated with an organosilicon compound having (i) a trialkoxysilyl group and (ii) not having a hydrogen atom bonded to a silicon atom: 5 to 50 parts by mass as the mass of (i), An addition-curing type silicone composition characterized by containing the above.

2. The addition-curing type silicone composition according to claim 1, wherein the component (C) contains an organohydrogenpolysiloxane represented by the following formula (3). 【Chemical 1】 (In the formula, R ３ is independently a hydrogen atom, a 2-(trimethoxysilyl)ethyl group or a 3-(trimethoxysilyl)propyl group, provided that one or more of R ３ are a 2-(trimethoxysilyl)ethyl group or a 3-(trimethoxysilyl)propyl group, and two or more of R ３ are hydrogen atoms. p is an integer from 0 to 50, q is an integer from 1 to 50, and the arrangement of the bracketed siloxane units is arbitrary.)

3. The addition-curing type silicone composition according to claim 1, wherein the organosilicon compound in the component (F) is an organopolysiloxane represented by the following formula (4). [Chemical Formula 2] (wherein R ４ is independently a methyl group or a methoxy group, n is an integer of 0 to 10, m is an integer of 1 to 50, and the arrangement of the siloxane units in parentheses is optional.)

4. A method for producing the addition-curing type silicone composition according to any one of claims 1 to 3, characterized by including a step of heat-treating a composition containing (i) titanium oxide and (ii) an organosilicon compound having a trialkoxysilyl group and not having a hydrogen atom bonded to a silicon atom at 100 to 180°C.

5. A silicone cured product for a light reflecting material, which is a cured product of the addition-curing type silicone composition according to any one of claims 1 to 3.

6. The silicone cured product for a light reflecting material according to claim 5, wherein the reflectance of light with a wavelength of 450 nm at a thickness of 2 mm is 95% or more.

7. A light reflecting material characterized by being composed of the silicone cured product for a light reflecting material according to claim 5.

8. An optical semiconductor device comprising the light reflecting material according to claim 7.

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