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

Abstract

The addition-curable silicone composition comprises (A) a specific linear organopolysiloxane, (B) an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms per molecule and having no alkenyl groups, (C) at least one filler selected from titanium oxide, silica, and alumina, and 10-1,000 mass parts per 100 mass parts of compound (A) of (D) an organopolysiloxane represented by formula (1) and (E) a platinum group metal catalyst. The total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5-3.0 times the total number of alkenyl groups bonded to silicon atoms in component (A) and component (D). As a result, there is provided an addition-curable silicone composition having good fluidity even when a polyorganosiloxane containing a fluoroalkyl group is highly filled with a filler.

Description

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

[0001] The present invention relates to an addition-curable silicone composition, a cured silicone product, and an optical semiconductor device.

[0002] In recent years, optical semiconductor elements such as light-emitting diodes (hereinafter referred to as "LEDs") have been widely used as indicators and light sources due to their high light emission efficiency and excellent driving and lighting cycle characteristics. In particular, white LEDs are widely used as backlights for display devices and camera flashes, and are also used for lighting purposes. These light-emitting devices are equipped with a material that reflects the emitted light in order to increase the light extraction efficiency in the direction of irradiation.

[0003] Lead frames used in LEDs often have the function of transmitting current and reflecting light. Specifically, silver plating, which has good light reflectivity, is preferred. However, silver plating has the problem of easily decreasing reflectivity due to oxidation and sulfurization when exposed to external gases. Gold plating or aluminum is sometimes used to prevent corrosion due to external gases, but both have the problem of low visible light reflectivity. In addition, light-reflecting resins or ceramics are used as insulating materials, and these parts are also required to have the function of reflecting light, but they do not necessarily have high light reflectivity.

[0004] To solve these problems, a method of thinly coating a highly light-reflecting resin on a lead frame or insulating material has been used. One such material is a silicone resin highly loaded with a light-reflective filler, which is considered to have good heat resistance and light resistance. However, high loading can cause the composition to exhibit thixotropy, reducing the fluidity (self-leveling) during coating and preventing the production of LEDs. Furthermore, reducing the amount of filler is undesirable because it reduces the light reflectivity during thin-film coating. Therefore, Patent Document 1 proposes a highly fluid, light-reflective material obtained by highly loading a silicone resin with titanium oxide powder whose surface has been treated with siloxane. However, in order to further increase the brightness of LEDs, there is a problem in that sufficient fluidity cannot be achieved when a low-refractive-index silicone resin containing a fluoroalkyl group is highly loaded with a filler that has been surface-treated using a conventional treatment agent.

[0005] Japanese Patent Application Laid-Open No. 2020-132824

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an addition-curable silicone composition that has good fluidity even when a fluoroalkyl group-containing polyorganosiloxane is highly filled with a filler.

[0007] In order to solve the above problems, the present invention provides a polymerizable compound having: (A) two or more silicon-bonded alkenyl groups and one or more silicon-bonded CF groups in one molecule; ３ -(CF ２ ) ａ - (CH ２ ) ｂ (B) an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule and having no alkenyl groups; (C) 10 to 1,000 parts by mass of one or more fillers selected from titanium oxide, silica, and alumina per 100 parts by mass of component (A); (D) an organopolysiloxane represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses appended with c and the siloxane units in the parentheses appended with d may be arranged randomly, in blocks, or alternately.), and (E) a platinum group metal catalyst, in which the total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 3.0 times the total number of alkenyl groups bonded to silicon atoms in components (A) and (D).

[0008] The addition-curable silicone composition has good fluidity, and upon curing, it gives a cured silicone product.

[0009] In this case, the component (C) is preferably rutile-type titanium oxide having a volume median diameter of 0.1 to 0.5 μm.

[0010] Such component (C) provides the composition with excellent flowability and the cured product with excellent light reflectivity.

[0011] Furthermore, as the component (D), R １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3.

[0012] Such a component (D) has excellent compatibility with components (A) and (B).

[0013] The addition-curable silicone composition preferably has a thixotropic ratio (viscosity at 1 rpm / viscosity at 10 rpm) of 2.0 or less at 23° C. as measured with an E-type rotational viscometer.

[0014] If the addition-curable silicone composition exhibits a thixotropic ratio of 2.0 or less, the addition-curable silicone composition will have superior fluidity.

[0015] The present invention also provides a cured silicone product, which is a cured product of the addition-curable silicone composition described above.

[0016] The silicone cured product of the present invention is useful as a coating material.

[0017] The present invention also provides an optical semiconductor device comprising the above-described silicone cured product.

[0018] Such optical semiconductor devices have excellent optical properties because they use the above-mentioned silicone cured product.

[0019] The present invention further provides an organopolysiloxane represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses to which c is attached and the siloxane units in the parentheses to which d is attached may be arranged randomly, in blocks, or alternately.

[0020] Adding such an organopolysiloxane to a silicone composition can impart fluidity to the composition even when a high concentration of filler is blended into the composition.

[0021] In this case, R in the formula (1) １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3.

[0022] Such an organopolysiloxane has excellent compatibility between the linear organopolysiloxane and the organosilicon compound.

[0023] As described above, the addition-curable silicone composition of the present invention has good fluidity even when the fluoroalkyl-containing silicone resin is highly loaded with filler. Therefore, the silicone cured product obtained from the addition-curable silicone composition of the present invention is useful as a coating material for optical semiconductors, etc., particularly as a light-reflecting coating material, and is also useful for optical semiconductor devices that use the silicone cured product.

[0024] As described above, there has been a need for the development of an addition-curable silicone composition that exhibits good fluidity even when a high amount of filler is added to a silicone resin containing a fluoroalkyl group.

[0025] As a result of extensive research into the above-mentioned problems, the present inventors discovered that the above-mentioned problems could be solved by using an addition-curable silicone composition containing a specific organopolysiloxane, and thus completed the present invention.

[0026] That is, the present invention provides an addition-curable silicone composition, comprising: (A) a silicone compound having two or more silicon-bonded alkenyl groups and one or more silicon-bonded CF groups in one molecule; ３ -(CF ２ ) ａ - (CH ２ ) ｂ (B) an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule and having no alkenyl groups; (C) 10 to 1,000 parts by mass of one or more fillers selected from titanium oxide, silica, and alumina per 100 parts by mass of component (A); (D) an organopolysiloxane represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses appended with c and the siloxane units in the parentheses appended with d may be arranged randomly, in blocks, or alternately.), and (E) a platinum group metal catalyst, wherein the total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 3.0 times the total number of alkenyl groups bonded to silicon atoms in components (A) and (D).

[0027] The present invention will be described in detail below, but the present invention is not limited thereto.

[0028] [Addition-Curable Silicone Composition] The addition-curable silicone composition of the present invention contains components (A) to (E) described below. Each component will be described in detail below.

[0029] <Component (A)> Component (A) is a compound having two or more silicon-bonded alkenyl groups and one or more silicon-bonded CF groups in one molecule. ３ -(CF ２ ) ａ - (CH ２ ) ｂ - groups (where a is an integer of 0 or greater and b is an integer of 1 or greater), and is a linear organopolysiloxane that does not have an alkoxy group bonded to a silicon atom or a hydroxyl group bonded to a silicon atom.

[0030] Examples of alkenyl groups bonded to silicon atoms include vinyl, allyl, butenyl, pentenyl, and hexenyl groups. Alkenyl groups having 2 to 10 carbon atoms, particularly 2 to 6 carbon atoms, are preferred, with vinyl groups being more preferred.

[0031] The number of alkenyl groups bonded to silicon atoms is two or more per molecule, and from the viewpoints of curability and the hardness of the resulting cured product, the number is preferably 2 to 10, and even more preferably 2. The alkenyl groups bonded to silicon atoms may be located either at the molecular chain terminals or non-terminal portions, or at both, but are preferably located at the molecular chain terminals only.

[0032] CF bonded to silicon atoms ３ -(CF ２ ) ａ - (CH ２ ) ｂ In the - group, a is an integer of 0 or more, and from the viewpoints of refractive index and availability of raw materials, a is preferably an integer of 0 to 9, more preferably 0. From the viewpoints of availability of raw materials and production, b is an integer of 1 or more, preferably an integer of 1 to 5, more preferably 2. Therefore, CF ３ -(CF ２ ) ａ - (CH ２ ) ｂThe - group is preferably a 3,3,3-trifluoropropyl group.

[0033] CF bonded to silicon atoms ３ -(CF ２ ) ａ - (CH ２ ) ｂ There may be one or more - groups per molecule, but from the perspective of refractive index, they preferably account for 20% or more of the total number of substituents bonded to silicon atoms in component (A). ３ -(CF ２ ) ａ - (CH ２ ) ｂ The upper limit of the number of - groups in one molecule is not particularly limited, but it can be set to, for example, 50%.

[0034] The substituents other than alkenyl groups and fluoroalkyl groups bonded to silicon atoms in component (A) are not particularly limited as long as they are not alkoxy groups or hydroxyl groups, but are preferably substituted or unsubstituted monovalent hydrocarbon groups having 1 to 8 carbon atoms. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, and butyl; cycloalkyl groups such as cyclohexyl and cyclopentyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl and phenylethyl; and chloroalkyl groups such as chloromethyl, chloropropyl, and chlorocyclohexyl. Alkyl groups are preferred, and methyl groups are more preferred.

[0035] The viscosity of component (A) at 23°C is preferably 1 to 100,000 mPa·s, and more preferably 10 to 10,000 mPa·s. A viscosity within this range provides better workability and results in a cured product with higher hardness. Unless otherwise specified below, viscosity is measured at 23°C using a Brookfield type rotational viscometer.

[0036] Specific examples of the component (A) include the following: [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ]２ [(CF ３ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ３０ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２ [(CF ３ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ５０ [(CH ３ ) ２ SiO ２／２ ] ２０ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２ [(CF ３ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ３０ [(C ４ F ９ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ２ (In the above formula, the siloxane units may be arranged in any order.)

[0037] The component (A) may be used alone or in combination of two or more types.

[0038] <Component (B)> Component (B) is an organosilicon compound that contains two or more silicon-bonded hydrogen atoms (i.e., SiH groups) per molecule and does not contain any alkenyl groups. Component (B) acts as a crosslinking agent that undergoes a hydrosilylation reaction with the alkenyl groups in components (A) and (D).

[0039] Component (B) is not particularly limited as long as it is an organosilicon compound that has two or more hydrogen atoms bonded to silicon atoms in one molecule and does not have an alkenyl group or an alkoxy group, and examples thereof include organohydrogensilanes and organohydrogenpolysiloxanes, with organohydrogenpolysiloxanes being preferred. There are no particular limitations on the molecular structure of the organohydrogenpolysiloxane, and for example, linear, cyclic, or branched ones can be used.

[0040] The silicon-bonded organic group in component (B) does not contain an alkenyl group, and examples thereof include unsubstituted monovalent hydrocarbon groups, or monovalent hydrocarbon groups substituted with a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom) or an epoxy-containing group (e.g., epoxy group, glycidyl group, glycidoxy group), etc. Examples of such substituted or unsubstituted monovalent hydrocarbon groups include alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 10 carbon atoms, and more preferably methyl or ethyl groups, as well as groups in which these groups are substituted with the substituents exemplified above. Furthermore, when the monovalent hydrocarbon group contains an epoxy-containing group as a substituent, adhesiveness can be imparted to the cured product of the silicone composition of the present invention.

[0041] From the viewpoint of further reducing the refractive index and improving compatibility with component (A), the silicon-bonded organic group in component (B) is preferably CF ３ -(CF ２ ) ａ - (CH ２ ) ｂ - group (wherein a and b have the same meanings as above).

[0042] Component (B) has at least two silicon-bonded hydrogen atoms (SiH groups) per molecule, preferably 2 to 200, and more preferably 3 to 100. When the organosilicon compound of component (B) has a linear or branched structure, these SiH groups may be located either at the molecular chain terminals or non-terminal portions, or may be located at both molecular chain terminals.

[0043] The number of silicon atoms per molecule of the organosilicon compound of component (B) (degree of polymerization) is preferably 2 to 1,000, more preferably 3 to 200, and even more preferably 4 to 100. Furthermore, the organosilicon compound of component (B) is preferably liquid at 23°C, and its viscosity at 23°C, measured with a rotational viscometer, is preferably 1 to 1,000 mPa·s, and more preferably 10 to 100 mPa·s.

[0044] The organosilicon compound of component (B) may be, for example, an organohydrogenpolysiloxane represented by the following formula (2). (In the formula, R ５ are the same or different, and each represents a substituted or unsubstituted monovalent hydrocarbon group that does not contain an alkenyl group, and h and i are numbers that satisfy the conditions 0.7≦h≦2.1, 0.001≦i≦1.0, and 0.8≦h+i≦3.0, preferably 1.0≦h≦2.0, 0.01≦i≦1.0, and 1.5≦h+i≦2.5.

[0045] (2) In the formula, R ５ Examples of the substituted or unsubstituted monovalent hydrocarbon group not containing an alkenyl group include unsubstituted monovalent hydrocarbon groups such as alkyl groups having 1 to 6 carbon atoms and aryl groups having 6 to 10 carbon atoms, more preferably methyl or ethyl groups, and examples of the substituted monovalent hydrocarbon group include monovalent hydrocarbon groups substituted with a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom) or an epoxy group-containing group (e.g., epoxy group, glycidyl group, glycidoxy group). Furthermore, when the monovalent hydrocarbon group has an epoxy group-containing group as a substituent, adhesiveness can be imparted to the cured product of the silicone composition of the present invention. Furthermore, from the viewpoint of further lowering the refractive index and improving compatibility with component (A), R ５ As a result, CF ３ -(CF ２ ) ａ - (CH ２ ) ｂ - group (wherein a and b have the same meanings as above).

[0046] Examples of organohydrogenpolysiloxanes represented by the above average composition formula (2) include those having a ratio of constituent units represented by the following formula:

[0047] [(CH ３ ) HSiO ２／２ ] ４ [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ８ [(CH ３ ) ３ SiO １／２ ] ２ [(CH ３ ) HSiO ２／２ ] ４ [(CF ３ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ６ [H(CH ３ ) ２ SiO １／２ ] ２ [(CF ３ -CH ２ -CH ２ ) (CH ３ ) SiO ２／２ ] ５ [(CH ３ ) ２ SiO ２／２ ] ２

[0048] The organohydrogenpolysiloxane represented by the average composition formula (2) is represented by the formula: H ３ SiO １／２ siloxane units represented by the formula: R ５ Siloxane units represented by HSiO and / or the formula: R ５ ２ HSiO １／２ The organohydrogenpolysiloxane may contain a siloxane unit represented by the formula: wherein the organohydrogenpolysiloxane contains a triorganosiloxane unit (M unit) that does not contain a SiH group, a diorganosiloxane unit (D unit), a monoorganosiloxane unit (T unit), and / or SiO４／２ In the above formula, R may contain a unit (Q unit). ５ is as shown in the above equation (2).

[0049] The component (B) may be used alone or in combination of two or more types.

[0050] The amount of component (B) to be added is such that the total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 3.0 times the total number of alkenyl groups bonded to silicon atoms in components (A) and (D), and from the viewpoint of crosslinking balance, the amount is preferably 0.7 to 2.0 times. If the amount is less than 0.5 times or more than 3.0 times, crosslinking may proceed insufficiently or excessively, and a cured product with excellent hardness may not be obtained.

[0051] <Component (C)> Component (C) is one or more fillers selected from titanium oxide, silica, and alumina, and is a component that imparts light reflectivity to the resulting cured product and improves its strength.

[0052] Titanium oxide is particularly preferred because it can efficiently reflect LED light, and is suitable as a coating material with high fluidity and high reflectivity for light from around 450 nm to 900 nm. From the viewpoint of durability, rutile type titanium oxide is preferred, and the surface may be treated with a surface treatment agent such as alumina, silica, or polyol.

[0053] The volume median diameter of component (C) is preferably 10 μm or less, more preferably 0.1 μm to 5 μm, and even more preferably 0.1 μm to 0.5 μm. Within this range, the balance between the fluidity of the composition and the light reflectivity and strength of the cured product is excellent. In the present invention, the volume median diameter refers to the median diameter (D) in the volume-based particle size distribution determined by the laser diffraction scattering method. ５０ ) refers to

[0054] The component (C) may use either a single compound or a combination of two or more compounds.

[0055] The amount of component (C) blended is 10 to 1,000 parts by mass, and preferably 50 to 500 parts by mass, per 100 parts by mass of component (A). If it is less than 10 parts by mass, the effects of imparting light reflectivity to the cured product or improving strength may not be obtained. On the other hand, if it exceeds 1,000 parts by mass, the fluidity of the composition may decrease.

[0056] <Component (D)> Component (D) is a polymer represented by the following formula (1), which has an alkoxy group bonded to a silicon atom at one end of the molecular chain and a CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ This component provides fluidity to the composition of the present invention even when a high concentration of filler is blended in. (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses to which c is attached and the siloxane units in the parentheses to which d is attached may be arranged randomly, in blocks, or alternately.

[0057] In the above formula (1), R １ In the formula, f is an integer of 0 or more, and from the viewpoints of refractive index and availability of raw materials, it is preferably an integer of 0 to 9, more preferably 0. From the viewpoints of availability of raw materials and production, g is an integer of 1 or more, preferably an integer of 1 to 5, more preferably 2. Therefore, R １ is preferably a 3,3,3-trifluoropropyl group.

[0058] In the above formula (1), R ２ Examples of the monovalent hydrocarbon group not having an addition-reactive carbon-carbon double bond include alkyl groups such as methyl, ethyl, propyl, and butyl, cycloalkyl groups such as cyclohexyl and cyclopentyl, aryl groups such as phenyl, tolyl, and xylyl, and aralkyl groups such as benzyl and phenylethyl. Preferred are alkyl groups, and more preferred are methyl groups.

[0059] In the above formula (1), R ３ Examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, and butyl, cycloalkyl groups such as cyclohexyl and cyclopentyl, aryl groups such as phenyl, tolyl, and xylyl, aralkyl groups such as benzyl and phenylethyl, and alkenyl groups such as vinyl, allyl, butenyl, hexenyl, and octenyl. Alkyl or alkenyl groups are preferred, and methyl or vinyl groups are more preferred.

[0060] In the above formula (1), R ４ Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, with a methyl group and an ethyl group being preferred, and a methyl group being more preferred.

[0061] In the above formula (1), c is an integer of 1 or more, preferably an integer of 1 to 50, and more preferably an integer of 10 to 30. If c is 0, the effects of reducing the viscosity and thixotropy of the composition cannot be obtained.

[0062] In the formula (1), d is an integer of 0 or greater, and is preferably an integer that satisfies d / (c+d)≦0.5, and more preferably an integer that satisfies d / (c+d)≦0.2. Within such a range, compatibility with components (A) and (B) is excellent, and the composition is excellent in terms of the effects of reducing viscosity and thixotropy.

[0063] In the above formula (1), e is an integer of 1 to 3, preferably 2 or 3.

[0064] In particular, the component (D) is R １is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3.

[0065] The viscosity of component (D) at 23° C. as measured with a rotational viscometer is preferably 0.1 to 5 Pa·s. Within this range, the composition is excellently effective in reducing viscosity and thixotropy.

[0066] The refractive index (25°C) of component (D) at a wavelength of 589 nm is preferably 1.35 to 1.39. If the refractive index is within this range, the light reflectance of the resulting cured product can be further improved.

[0067] Specific examples of the component (D) include organopolysiloxanes represented by the following formulas (3) to (6), but are not limited to these.

[0068] The component (D) may be used alone or in combination of two or more types.

[0069] The blend amount of component (D) is preferably in the range of 0.1 to 10 parts by mass per 100 parts by mass of component (A), as this range provides excellent effects of reducing the viscosity and thixotropy of the composition.

[0070] <Component (E)> The platinum group metal catalyst of component (E) is a component that promotes and accelerates the hydrosilylation reaction between the alkenyl groups in components (A) and (D) and the silicon-bonded hydrogen atoms of component (B).

[0071] The platinum group metal catalyst is not particularly limited, and examples thereof include platinum group metals such as platinum, palladium, and rhodium; platinum 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, silicone-modified chloroplatinic acid is preferred because it has good compatibility with components (A) and (B) and contains almost no chlorine impurities.

[0072] The component (E) may use either a single compound or a combination of two or more compounds.

[0073] The amount of component (E) to be added may be any amount that is effective as a catalyst, but is preferably 1 to 500 ppm, preferably 3 to 100 ppm, and more preferably 5 to 30 ppm, calculated as the mass of platinum group metal element relative to component (A). By adding component (E) in an appropriate amount, the hydrosilylation reaction can be promoted more effectively.

[0074] <Other Components> In addition to the components (A) to (E) described above, the addition-curable silicone composition of the present invention may also contain other components, such as those exemplified below.

[0075] (Silicone Resin) The addition-curable silicone composition of the present invention may contain, as needed, SiO ３／２ Units or SiO ２ The silicone resin may contain a silicone resin having a unit. From the viewpoint of compatibility, the silicone resin is preferably one having a fluoroalkyl group bonded to a silicon atom and an alkenyl group bonded to a silicon atom, and is preferably one having a weight average molecular weight in the range of 500 to 100,000 in terms of standard polystyrene measured by gel permeation chromatography (GPC). Specific examples of silicone resins include those having an average constitutional unit ratio represented by the following formula: [(CH ３ ) ３ SiO １／２ ] １．８ [(CH ２ =CH)(CH ３ ) ２SiO １／２ ] ３．２ [SiO ４／２ ] ４．３ [(CF ３ -CH ２ -CH ２ )SiO ３／２ ] １０．０ [(CH ３ ) ３ SiO １／２ ] １．３ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２．３ [SiO ４／２ ] ３．９ [(CF ３ -CH ２ -CH ２ )SiO ３／２ ] ５．９ [(CH ２ =CH)(CH ３ )SiO ２／２ ] ２．１ [(CF ３ -CH ２ -CH ２ )SiO ３／２ ] １０．１ [(CH ３ ) ２ SiO ２／２ ] ０．７ [(CH ２ =CH)(CH ３ )SiO ２／２ ] ２．１ [(CF ３ -CH ２ -CH ２ )SiO ３／２ ] １０．１ [(CF ３ -(CF ２ ) ３ -CH ２ -CH ２ )(CH ３ )SiO ２／２ ] ０．７

[0076] When a silicone resin is used, the blending amount is preferably 0.05 to 100 parts by mass, more preferably 0.1 to 50 parts by mass, per 100 parts by mass of component (A). Within this range, it is preferable in terms of the hardness and adhesiveness of the resulting cured product.

[0077] (Reaction Inhibitor) A reaction inhibitor may be added to the addition-curable silicone composition of the present invention in order to adjust the curing rate.

[0078] Examples of reaction inhibitors 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; 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, and ethynylmethyldecylcarbinol.

[0079] Since the degree of curing inhibition effect of the reaction inhibitor varies depending on the chemical structure of the reaction inhibitor, it is desirable to adjust the amount of the reaction inhibitor to an optimal amount for each reaction inhibitor used. Preferably, it is 0.001 to 5 parts by mass per 100 parts by mass of the above component (A). If the amount is 0.001 part by mass or more, the long-term storage stability of the composition at room temperature can be sufficiently obtained. If the amount is 5 parts by mass or less, there is no risk of inhibiting the curing of the composition.

[0080] (Adhesion Improver) The addition-curable silicone composition of the present invention may contain an adhesion improver to improve its adhesion. This adhesion improver may be an organosilicon compound such as a silane or siloxane containing a functional group that imparts adhesion, or a non-silicon organic compound.

[0081] Specific examples of functional groups that impart adhesiveness include alkenyl groups such as vinyl groups and allyl groups bonded to silicon atoms; epoxy groups (e.g., 3-glycidoxypropyl group, 2-(3,4-epoxycyclohexyl)ethyl group, etc.), acryloxy groups (e.g., 3-acryloxypropyl group, etc.), methacryloxy groups (e.g., 3-methacryloxypropyl group, etc.) bonded to silicon atoms via carbon atoms; and alkoxysilyl groups (e.g., trimethoxysilyl group, triethoxysilyl group, methyldimethoxysilyl group, etc. alkoxysilyl groups bonded to silicon atoms via alkylene groups which may contain 1 to 2 ester structures, urethane structures, or ether structures).

[0082] Examples of non-silicon organic compounds include unsaturated carboxylic acid allyl esters such as acrylic acid, methacrylic acid, and vinylacetic acid; aromatic carboxylic acid allyl esters such as benzoic acid allyl ester, phthalic acid diallyl ester, and pyromellitic acid tetraallyl ester; saturated fatty acid allyl esters such as acetate allyl ester, propionate allyl ester, butyrate allyl ester, valerate allyl ester, and laurate allyl ester; and triallyl isocyanurate.

[0083] When an adhesion improver is used, the blending amount is preferably 0.1 to 20 parts by mass, and more preferably 0.3 to 10 parts by mass, per 100 parts by mass of component (A). With such a blending amount, the addition-curable silicone composition and its cured product effectively improve the adhesion to substrates and are less likely to become discolored.

[0084] The thixotropic ratio (viscosity at 1 rpm / viscosity at 10 rpm) of the addition-curable silicone composition of the present invention at 23°C, as measured with an E-type rotational viscometer, is 2.0 or less, and preferably 1.0 to 1.5. If the ratio is within this range, the addition-curable silicone composition will have high fluidity.

[0085] [Method for Producing Addition-Curable Silicone Composition] The addition-curable silicone composition of the present invention can be produced by mixing components (A) to (E) and, depending on the purpose, other components. It is also preferable to mix components (A), (C), and (D) and then perform a heat treatment. The heat treatment bonds component (D) to the filler surface of component (C) through a hydrolysis and condensation reaction, thereby improving the fluidity of the composition. The heat treatment temperature is preferably 80 to 160°C, and the heat treatment time is preferably 30 minutes to 5 hours, more preferably 1 to 3 hours. It is also preferable to perform the heat treatment under reduced pressure conditions in order to efficiently remove the alcohol and water by-products generated by the hydrolysis and condensation reaction of the alkoxy groups on the filler surface and promote the reaction.

[0086] [Cured Product] The present invention also provides a cured product (cured silicone product) of the addition-curable silicone composition.

[0087] The addition-curable silicone composition of the present invention can be cured preferably at a temperature of 100 to 150° C. The curing time is usually about 30 minutes to 4 hours, preferably 30 minutes to 1 hour.

[0088] The addition-curable silicone composition of the present invention is cured at 120°C for 1 hour to produce a sheet having a hardness (Durometer Type A hardness) of preferably 20 to 90.

[0089] Within this range, sufficient rubber strength is obtained, and defects such as cracks can be prevented.

[0090] [Optical Semiconductor Device] The present invention further provides an optical semiconductor device comprising the above-described silicone cured product.

[0091] The addition-curable silicone composition of the present invention has excellent fluidity and can be dispensed using a dispenser around an LED element placed on a substrate made of, for example, an FRP (fiber reinforced plastic) resin using an epoxy resin, and then cured to form a uniform coating film on the substrate.As a result, optical semiconductor devices using the addition-curable silicone composition of the present invention have excellent optical properties.

[0092] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these. The viscosity at 23°C is a measurement value using an E-type rotational viscometer at 1 rpm and 10 rpm, and the refractive index is the refractive index (nD25) of light with a wavelength of 589 nm at 25°C measured using a refractometer (RX-5000, manufactured by Atago Co., Ltd.). The abbreviations for each siloxane unit have the following meanings. M: (CH ３ ) ３ SiO １／２ M Ｖｉ : (CH ２ =CH)(CH ３ ) ２ SiO １／２ D Ｆ :(CF ３ CH ２ CH ２ ) (CH ３ ) SiO ２／２ D Ｈ : H(CH ３ ) SiO ２／２

[0093] Synthesis Example 1: 293.9 g of 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane and 12.2 g of trimethylsilanol were placed in a 500 mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer, and the mixture was stirred to form a homogeneous solution. 0.72 g of a compound represented by the following formula (7) was added as a catalyst, and the mixture was stirred at 50°C for 24 hours. Next, 0.05 g of acetic acid was added, and the mixture was stirred at 100°C for 1 hour to carry out a neutralization reaction. 55 g of a compound represented by the following formula (8) was added as an end-blocking agent, and the mixture was stirred at 60°C for 3 hours. After introducing trimethoxysilyl groups, an additional 55 g of methanol was added and the mixture was stirred at 60°C for 2 hours. The resulting solution was concentrated under reduced pressure at 150°C for 1 hour and filtered to obtain a colorless, transparent liquid (viscosity 1.0 Pa s, refractive index 1.380). NMR measurement and GPC (gel permeation chromatography) confirmed that an organopolysiloxane represented by the following formula (9) was obtained.

[0094] Synthesis Example 2: 100 g of an organopolysiloxane represented by the following formula (10) was placed in a 500 mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer. 8.4 g of the compound represented by the above formula (8) was added dropwise thereto, and the mixture was stirred at 60°C for 3 hours. 6.8 g of dimethylvinylchlorosilane and 10.5 g of 1,3-divinyl-1,1,3,3-tetramethyldisilazane were then added, and the mixture was allowed to react at 110°C for 2 hours. The resulting solution was concentrated under reduced pressure at 100°C for 2 hours and filtered to obtain a colorless, transparent liquid (viscosity 0.35 Pa s, refractive index 1.381). NMR measurement and GPC confirmed that an organopolysiloxane represented by the following formula (11) had been obtained.

[0095] Synthesis Example 3: 100 g of the organopolysiloxane represented by the above formula (10) was placed in a 500 mL four-neck flask equipped with a stirrer, a condenser, a dropping funnel, and a thermometer. 25 g of the compound represented by the above formula (8) was added dropwise thereto, and the mixture was stirred at 60°C for 3 hours. 26 g of methanol was then added and the mixture was stirred at 60°C for 2 hours. The resulting solution was concentrated under reduced pressure at 100°C for 1 hour and filtered to obtain a colorless, transparent liquid (viscosity 0.42 Pa s, refractive index 1.379). NMR measurement and GPC confirmed that the compound represented by the following formula (12) was obtained.

[0096] Examples 1 to 3, Comparative Examples 1 to 5 The following components were mixed in the amounts (parts by mass) shown in Table 1 to prepare addition-curable silicone compositions.

[0097] That is, first, components (A), (C), and (D) were mixed for 1 hour at 25°C using a 5-liter gate mixer (manufactured by Inoue Seisakusho Co., Ltd., product name: 5-liter planetary mixer), and then heat-treated for 2 hours at 100°C and a reduced pressure of 0.1 kPa. Next, component (B) and components (E) to (G) were added at 25°C and mixed for 30 minutes to obtain an addition-curable silicone composition.

[0098] (A) Component: (A-1)M Ｖｉ ２ D Ｆ ３０(A-2)M (viscosity at 23°C: 2,000 mPa·s, vinyl group content: 0.037 mol / 100 g) Ｖｉ ２ D Ｆ ３３０ (viscosity at 23°C: 100,000 mPa·s, vinyl group content: 0.0046 mol / 100 g)

[0099] (B) Component: M ２ D Ｆ ６ D Ｈ ４ (viscosity at 23°C: 25 mPa·s, hydrogen gas generation rate: 75 ml / g)

[0100] Component (C): Titanium oxide (PF-691 manufactured by Ishihara Sangyo Kaisha, Ltd., volume median diameter 0.21 μm, polyol surface treatment)

[0101] Component (D): (D-1) Organopolysiloxane obtained in Synthesis Example 1 (D-2) Organopolysiloxane obtained in Synthesis Example 2 (D-3) 3-glycidyloxypropyltrimethoxysilane (comparative component) (D-4) 3,3,3-trifluoropropyltrimethoxysilane (comparative component) (D-5) Organopolysiloxane represented by the following formula (13) (comparative component) (D-6) Organopolysiloxane obtained in Synthesis Example 3 (comparative component)

[0102] Component (E): A toluene solution of the reaction product of hexachloroplatinic acid and 1,3-divinyltetramethyldisiloxane (platinum concentration: 0.5 wt%)

[0103] Component (F): Reaction inhibitor: Ethynylcyclohexanol

[0104] Component (G): Adhesion improver 3-methacryloxypropyltrimethoxysilane

[0105] The addition-curable silicone resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were evaluated as follows, and the results are shown in Table 2.

[0106] [Viscosity and Thixotropic Ratio] The viscosity of the addition-curable silicone composition at 23°C was measured at 1 rpm and 10 rpm using an E-type viscometer (TVE25H, manufactured by Toki Sangyo Co., Ltd.). The thixotropic ratio (viscosity at 1 rpm / viscosity at 10 rpm) was also calculated to evaluate fluidity. The smaller the value, the lower the thixotropy and the better the fluidity of the composition.

[0107] [Hardness] The addition-curable silicone composition was cured at 150°C for 1 hour to obtain a cured silicone product, and the durometer type A hardness of the cured silicone product at 25°C was measured in accordance with JIS-K6249:2003.

[0108] [Light Reflectance] The addition-curable silicone composition was cured at 150°C for 1 hour to produce a 0.3 mm thick silicone cured product. The relative light reflectance of the resulting cured product at a wavelength of 450 nm was measured using a spectrophotometer U-3310 manufactured by Hitachi, Ltd. with a Φ60 integrating sphere attachment, using a barium sulfate plate as the blank (100%).

[0109]

[0110]

[0111] As shown in Table 2, the addition-curable silicone compositions of Examples 1 to 3 had low viscosities at low speeds (1 rpm) and low thixotropic ratios of 1.1 or less, resulting in excellent flowability (fluidity) during application. On the other hand, Comparative Example 1, which did not contain an organopolysiloxane as component (D), and Comparative Examples 2 and 3, in which component (D) was replaced with trimethoxysilane, exhibited thixotropy due to the titanium oxide, resulting in poor fluidity. Furthermore, Comparative Example 4, in which component (D) was replaced with a dimethylpolysiloxane terminated at one end with a trimethoxysilyl group and not containing a fluoroalkyl group, resulted in low compatibility with components (A) and (B), resulting in a high thixotropic ratio and poor fluidity. Furthermore, Comparative Example 5, in which component (D) was replaced with an organopolysiloxane terminated at both molecular chain ends with a fluoroalkyl group, also had a high thixotropic ratio and poor fluidity.

[0112] As described above, the addition-curable silicone composition of the present invention exhibits good fluidity even when the silicone resin containing a fluoroalkyl group is highly filled with a filler, and the addition-curable silicone composition of the present invention is useful for silicone cured products and optical semiconductor devices.

[0113] The present specification includes the following aspects: [1] An addition-curable silicone composition, comprising: (A) a compound having, in one molecule, two or more silicon-bonded alkenyl groups and one or more silicon-bonded CF ３ -(CF ２ ) ａ - (CH ２ ) ｂ (B) an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule and having no alkenyl groups; (C) 10 to 1,000 parts by mass of one or more fillers selected from titanium oxide, silica, and alumina per 100 parts by mass of component (A); (D) an organopolysiloxane represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses appended with c and the siloxane units in the parentheses appended with d may be arranged randomly, in blocks, or alternately with respect to each other.) and (E) a platinum group metal catalyst, wherein the total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 3.0 times the total number of alkenyl groups bonded to silicon atoms in components (A) and (D). [2] The addition-curable silicone composition according to [1], wherein component (C) is rutile-type titanium dioxide having a volume median diameter of 0.1 to 0.5 μm. [3] The addition-curable silicone composition according to [1], wherein component (D) is a rutile-type titanium dioxide having a volume median diameter of 0.1 to 0.5 μm, １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3. [4] The addition-curable silicone composition according to any one of [1] to [3], characterized in that it has a thixotropic ratio (viscosity at 1 rpm / viscosity at 10 rpm) of 2.0 or less at 23°C as measured with an E-type rotational viscometer. [5] A silicone cured product, characterized in that it is a cured product of the addition-curable silicone composition according to any one of [1] to [4]. [6] An optical semiconductor device, characterized in that it comprises the silicone cured product according to [5]. [7] An organopolysiloxane, characterized in that it is represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or more, d is an integer of 0 or more, and e is an integer of 1 to 3. The siloxane units in the parentheses to which c is attached and the siloxane units in the parentheses to which d is attached may be arranged randomly, in blocks, or alternately.) [8] R in the formula (1) １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3.

[0114] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. An addition-curable silicone composition comprising: (A) two or more silicon-bonded alkenyl groups and one or more silicon-bonded CF groups in one molecule; ３ -(CF ２ ) ａ - (CH ２ ) ｂ (B) an organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule and having no alkenyl groups; (C) 10 to 1,000 parts by mass of one or more fillers selected from titanium oxide, silica, and alumina per 100 parts by mass of component (A); (D) an organopolysiloxane represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses appended with c and the siloxane units in the parentheses appended with d may be arranged randomly, in blocks, or alternately with respect to each other.) and (E) a platinum group metal catalyst, wherein the total number of hydrogen atoms bonded to silicon atoms in component (B) is 0.5 to 3.0 times the total number of alkenyl groups bonded to silicon atoms in components (A) and (D).

2. The addition-curable silicone composition according to claim 1, wherein component (C) is rutile-type titanium dioxide having a volume median diameter of 0.1 to 0.5 μm.

3. As the component (D), R in the formula (1) １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ is a methyl group, c is an integer of 1 to 30, d is 0, and e is 2 or 3.

4. The addition-curable silicone composition according to claim 1, characterized in that the thixotropic ratio (viscosity at 1 rpm / viscosity at 10 rpm) at 23°C measured with an E-type rotational viscometer is 2.0 or less.

5. A cured silicone product, which is a cured product of the addition-curable silicone composition according to any one of claims 1 to 4.

6. An optical semiconductor device comprising the silicone cured product according to claim 5.

7. An organopolysiloxane characterized by being represented by the following formula (1): (In the formula, R １ are each independently, CF ３ -(CF ２ ) ｆ - (CH ２ ) ｇ - (wherein f is an integer of 0 or more, and g is an integer of 1 or more), and R ２ are each independently a monovalent hydrocarbon group having no addition-reactive carbon-carbon double bond, and R ３ are each independently a monovalent hydrocarbon group, and R ４ are each independently a hydrogen atom or an alkyl group, c is an integer of 1 or greater, d is an integer of 0 or greater, and e is an integer of 1 to 3. The siloxane units in the parentheses to which c is attached and the siloxane units in the parentheses to which d is attached may be arranged randomly, in blocks, or alternately.

8. R in the formula (1) １ is a trifluoropropyl group, and R ２ is a methyl group, and R ３ is a methyl group or a vinyl group, and R ４ 8. The organopolysiloxane according to claim 7, wherein: is a methyl group; c is an integer of 1 to 30; d is 0; and e is 2 or 3.

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