JP7108432B2 - Addition type silicone resin composition and optical semiconductor device using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an addition-type silicone resin composition having heat resistance and little initial coloring, and an optical semiconductor device using the same.

Conventionally, addition-type silicone resin compositions have been used as sealing agents for optical semiconductors (hereinafter referred to as LEDs) due to their excellent heat resistance. Since the temperature of recent LEDs increases with the increase in output, there is a demand for a heat-resistant LED encapsulant that exhibits little change in physical properties even at such high temperatures. Patent Document 1 proposes a silicone gel composition having excellent heat resistance.

However, in the silicone gel composition, the reaction product blended to impart heat resistance may have a strong yellowish tint from the beginning, so the composition tends to be colored and lack transparency, and the LED encapsulant There is a problem that the brightness of the LED tends to decrease when used as

JP 2008-291148 A

The problem to be solved by the present invention is to provide an addition-type silicone resin composition which has heat resistance and little initial coloration, and an optical semiconductor device using the same.

In order to solve the above problems, the invention according to claim 1 provides a linear dimethylvinylpolysiloxane (A1) having at least two silicon-bonded alkenyl groups that react with SiH groups in one molecule, and SiH in one molecule. A branched dimethylvinylpolysiloxane (A2) having at least two silicon-bonded alkenyl groups reactive with groups, an organohydrogenpolysiloxane (B) having at least two SiH groups in one molecule, and an addition-type silicone resin composition comprising a curing catalyst (C) and a heat resistance imparting agent (D),
The heat resistance imparting agent (D) is
a silazane compound (D1) represented by the following general formula (1);
^{R1R2R3SiNH ( R4R5SiNH ) nSiR6R7R8 ( 1 )} _{_}
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different monovalent hydrocarbon groups, and n is 0 or an integer of 1 or more. )
cerium carboxylate (D2) represented by the following general formula (2),
( ^R9COO ) _mCe (2)
(In the formula, R ⁹ is a monovalent hydrocarbon group of the same or different type, and m is 3 or 4). (M1),
Ce( ^R12 )(R13) ^{( R14} ) ⁽ R15)n (3)
(wherein R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are —OSiR ¹⁶ R ¹⁷ R ¹⁸ , R ¹⁶ , R ¹⁷ and R ¹⁸ are the same or different monovalent hydrocarbon groups, n is 0 or 1)
Provided is an addition-type silicone resin composition comprising:

A second aspect of the invention provides an optical semiconductor device, wherein a semiconductor element is encapsulated with a cured product of the addition-type silicone resin composition of the first aspect.

ADVANTAGE OF THE INVENTION The addition type silicone resin composition of this invention has the effect that it is highly transparent with low yellowness, and there is no deterioration of physical properties even if it is left at high temperature for a long time, and yellowness hardly changes. Therefore, when it is used as an LED encapsulant, there is an effect that the brightness of the LED does not decrease.

The addition-type silicone resin composition according to the present invention will be specifically described below.

<Linear organovinylpolysiloxane (A1)>
Linear organovinylpolysiloxane (A1) has at least two silicon-bonded alkenyl groups that react with SiH groups in one molecule, and the alkenyl groups are vinyl groups, allyl groups, propenyl groups, isopropenyl groups, and butenyl groups. a carbon-carbon double bond such as a group, an isobutenyl group, a hexenyl group, and the like. The straight-chain organovinylpolysiloxane (A1) is exemplified by, for example, a main chain composed of repeating diorganosiloxanes composed of D units (SiO _2/2 ) and a triorganosiloxane structure at the terminal. Examples of organo groups bonded to silicon at terminals and repeating units include methyl group, ethyl group, and phenyl group. A specific example is dimethylvinylpolysiloxane having vinyl groups at both ends.

<Branched Organovinylpolysiloxane (A2)>
Branched organovinylpolysiloxane (A2), having at least two silicon-bonded alkenyl groups that react with SiH groups in one molecule, wherein said alkenyl groups are vinyl, allyl, propenyl, isopropenyl and butenyl groups , an isobutenyl group, a hexenyl group, and the like. The branched organovinylpolysiloxane (A2) is, for example, a diorganopolysiloxane containing D units (SiO _2/2 ) and at least T units (SiO _3/2 ) or Q units (SiO _4/2 ) in the main chain. Examples include those consisting of repeated siloxanes and terminated with a triorganosiloxane structure. Examples of organo groups bonded to silicon at terminals and repeating units include methyl group, ethyl group, and phenyl group. A specific example is dimethylvinylpolysiloxane having terminal vinyl groups.

<Organohydrogenpolysiloxane (B)>
Organohydrogenpolysiloxane (B) has at least two SiH groups in one molecule and contains two or more SiH groups at least at terminals or in repeating structures. The content of hydrogen atoms bonded to silicon atoms is preferably 1.0 mmol/g to 20.0 mmol/g, and when it is 1.0 mmol/g or more, the curability is improved and hardness is easily obtained. . If the hydrogen atom content exceeds 20.0 mmol/g, the surface of the cured product tends to be tacky. In order to obtain good hardness, the hydrogen atom content ratio is more preferably 1.5 mmol/g or more. The hydrogen atom content is more preferably less than 10.0 mmol/g in order to prevent tackiness. Examples of organo groups bonded to silicon atoms include methyl, ethyl, and phenyl groups. The organohydrogenpolysiloxane may be, for example, linear or branched, and a specific example is dimethylhydrogenpolysiloxane.

<Curing catalyst (C) required for addition reaction>
The curing catalyst (C) necessary for the addition reaction is added to promote the hydrosilylation reaction of the components (A1), (A2) and (B), and is a known metal having catalytic activity for the hydrosilylation reaction. , metal compounds, metal complexes, and the like can be used. It is particularly preferable to use platinum, platinum compounds, and complexes thereof. These catalysts may be used alone or in combination of two or more. Moreover, you may use a co-catalyst together. The content of the curing catalyst (C) is preferably 0.1 ppm to 1000 ppm, more preferably 0.5 to 200 ppm, and even more preferably 1 to 50 ppm, based on the total composition.

<Heat resistance imparting agent (D)>
The addition-type silicone resin composition according to the present invention contains, in addition to the components (A1), (A2), (B), and (C), a heat resistance imparting agent (D )including. The heat resistance-imparting agent (D) is
a silazane compound (D1) represented by the following general formula (1);
^{R1R2R3SiNH ( R4R5SiNH ) nSiR6R7R8 ( 1 )} _{_}
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different monovalent hydrocarbon groups, and n is 0 or an integer of 1 or more. )
cerium carboxylate (D2) represented by the following general formula (2),
( ^R9COO ) _mCe (2)
(wherein R9 is the same or different monovalent hydrocarbon group and m is ³ or 4)
A cerium compound (M1) represented by the following general formula (3) obtained by heat treating at 80 ° C. or higher,
Ce( ^R12 )(R13) ^{( R14} ) ⁽ R15)n (3)
(wherein R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are —OSiR ¹⁶ R ¹⁷ R ¹⁸ , R ¹⁶ , R ¹⁷ and R ¹⁸ are the same or different monovalent hydrocarbon groups, n is 0 or 1).

The cerium compound (M1) is preferably stored as an organic solvent dispersion or a silicone dispersion, and examples of the organic solvent include aromatic solvents such as toluene and xylene. The heat resistance-imparting agent (D) referred to in the present invention is a composition containing the cerium compound (M1), specifically in other words, an organic solvent dispersion of the cerium compound ( M1) or a silicone dispersion.

The silicone may be any conventionally known organopolysiloxane having a viscosity of 10 to 10,000 mPa·s at 25° C., which is composed essentially of repeating diorganopolysiloxane units (straight-chain structure). It is linear or branched to retain liquid. An organic group bonded to a silicon atom (that is, an unsubstituted or substituted monovalent hydrocarbon group) is specifically an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group; a methoxy group, an ethoxy group, Alkoxy and hydroxy groups such as propoxy and butoxy; alkenyl groups such as vinyl; aryl groups such as phenyl, tolyl and naphthyl; cycloalkyl groups such as cyclohexyl; It is selected from groups in which some or all of the atoms are substituted with halogen atoms, cyano groups, etc., such as chloromethyl groups, fluoropropyl groups, cyanomethyl groups, and the like. The organopolysiloxane has a trialkylsiloxy group such as a trimethylsiloxy group, an alkenyldialkylsiloxy group such as a vinyldimethylsiloxy group, a dialkenylalkylsiloxy group such as a divinylmethylsiloxy group, a trivinylsiloxy group, and the like. and those blocked with a triorganosiloxy group such as a trialkenylsiloxy group of , a hydroxyl group, an alkoxy group, or the like. A mixture of these various organopolysiloxanes may also be used. Specific examples include polymethylsiloxane, polymethylvinylsiloxane, polymethylhydrogensiloxane, polymethylphenylsiloxane, polymethylphenylvinylsiloxane, and polymethylphenylhydrogensiloxane.

The silazane compound (D1) is a compound having a silicon-nitrogen bond in the molecule as shown in formula (1), and can be exemplified by hexamethyldisilazane.

Examples of the carboxylic acid of the cerium carboxylate (D2) include 2-ethylhexanoic acid, naphthenic acid, oleic acid, lauric acid, and stearic acid. The cerium carboxylate is preferably used as a carboxylic acid solution or an organic solvent solution. Examples of the organic solvent include standard solvents, mineral spirits, ligroin, petroleum solvents such as petroleum ether, toluene, xylene and the like. Aromatic solvents are exemplified.

Component (D2) is added in an amount of 5 to 50 parts by weight, preferably 10 to 25 parts by weight, per 100 parts by weight of component (D1). If the amount added is less than 5 parts by weight, the cerium compound (M1) is difficult to obtain the expected heat resistance. .

The heat resistance imparting agent (D) component is a product obtained by mixing components (D1) and (D2) in an organic solvent and then heat-treating the mixture at a temperature of 80°C or higher and 150°C or lower. is a cerium compound (M1) obtained by removing the by-product of by heating and depressurization, nitrogen purge, or the like.

The obtained cerium compound (M1) is preferably dispersed in the above organopolysiloxane in order to obtain compatibility with silicone and storage stability. An organopolysiloxane such as dimethylpolysiloxane is added dropwise to the cerium compound (M1) while stirring, and heated and stirred at 80° C. or higher under a reduced pressure of 100 mmHg or lower to convert the organic solvent dispersion into an organopolysiloxane dispersion. Substitution is possible.

The heat resistance imparting agent (D) component is added in an amount of 0.1 ppm to 300 ppm, preferably 0.1 ppm to 300 ppm, in terms of cerium metal, based on a total of 100 parts by weight of component (A1) and components (A2), (B), and (D). The amount is 0.5 ppm to 200 ppm. When the amount of cerium metal in component (D) is less than 0.1 ppm with respect to a total of 100 parts by weight of components (A1), (A2), (B), and (D), the effect of improving heat resistance at high temperatures is obtained. On the contrary, when it exceeds 200 ppm, the transparency of the composition is lowered.

The addition-type silicone composition of the present invention is cured by mixing the above components (A1), (A2), (B), (C) and (D). At that time, it is possible to separate and mix the main agent part consisting of components (A1), (A2), (C) and (D), and the curing agent part consisting of component (B).

<Other optional ingredients>

The present composition may contain, as other optional ingredients, alkyne alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, ethynylcyclohexanol; Enyne compounds such as 3-pentene-1-yne and 3,5-dimethyl-3-hexene-1-yne; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane , 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, compounds having aliphatic unsaturated bonds such as 1,3-divinyltetramethyldisiloxane, reactions of benzotriazole, etc. It may contain an inhibitor. The content of this reaction inhibitor is 0.0001 per 100 parts by weight in total of the components (A1), (A2), (B), (C), and (D) as a content that does not suppress the curability. It is preferably in the range of to 1 part by weight.

In addition, the present composition may contain an adhesion-imparting agent in order to improve its adhesiveness. As this adhesion imparting agent, an epoxy group- or alkoxy group-containing organosilicon compound, or a condensate thereof may be used. The alkoxy group is exemplified by methoxy, ethoxy, propoxy, butoxy and methoxyethoxy, with methoxy being particularly preferred. In addition, as the group other than the alkoxy group bonded to the silicon atom of the organosilicon compound, a substituted or unsubstituted monovalent hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group, an aralkyl group, and a halogen-substituted alkyl group; -glycidoxyalkyl groups such as glycidoxypropyl group and 4-glycidoxybutyl group; epoxy groups such as 2-(3,4-epoxycyclohexyl)ethyl group and 3-(3,4-epoxycyclohexyl)propyl group; Cyclohexylalkyl group; epoxy group-containing monovalent organic group such as oxiranylalkyl group such as 4-oxiranylbutyl group and 8-oxiranyloctyl group; acrylic group-containing monovalent organic group such as 3-methacryloxypropyl group group; hydrogen atom is exemplified. For example, tris(3-trimethoxysilylpropyl)isocyanurate is preferably used to improve adhesiveness while maintaining heat resistance. The organosilicon compound preferably has a group capable of reacting with component (A1), component (A2) or component (B). Specifically, it has a silicon-bonded alkenyl group or a silicon-bonded hydrogen atom. is preferred. Further, the organosilicon compound preferably has at least one epoxy group-containing monovalent organic group in one molecule because it can impart good adhesiveness to various substrates.

In addition, the present composition may contain an antioxidant in order to further improve heat resistance. As this antioxidant, one commonly used can be used. Examples include hindered phenol antioxidants, phosphorus antioxidants, hindered amine antioxidants, and thioether antioxidants. The content of this antioxidant is in the range of 0.0001 to 1 part by weight per 100 parts by weight in total of components (A1), (A2), (B), (C), and (D). preferable.

In addition, calcium carbonate, silica sand, talc, carbon black, titanium oxide, zinc oxide, kaolin, silicon dioxide, and melamine are added to the present composition as optional ingredients to adjust viscosity and hardness to the extent that they do not impair the object of the invention. It may contain inorganic fillers such as organic fillers, reinforcing materials such as glass fibers for reinforcing the cured resin, and hollow bodies such as shirasu balloons and glass balloons for weight reduction and viscosity adjustment. can. In addition, antioxidants, organic pigments, fluorescent pigments, corrosion inhibitors and the like can be used as appropriate.

The optical semiconductor device according to claim 3 of the present invention is an optical semiconductor device in which an optical semiconductor element such as an optical semiconductor (LED) is encapsulated with the cured product of the addition-type silicone resin composition according to claim 1 or 2. It is an optical semiconductor device with

Next, the addition-type silicone resin composition of the present invention will be described in detail with reference to examples and comparative examples.

<Preparation of heat resistance imparting agent (D) and heat resistance imparting agent (d1)>
8.0 g of hexamethyldisilazane (D1) and 2.4 g of 2-ethylhexanoic acid cerium salt (III (trivalent)) (cerium content: 12% by weight, manufactured by Aldrich) (D2) were added to 100 g of xylene to increase the reaction rate. 1.5 g of ion-exchanged water was mixed to accelerate the reaction, heated to 140° C., nitrogen was injected at 1 L/min, and the generated by-products were removed while stirring for 1 hour. A dispersion was obtained. The cerium compound (M1) was identified by H (proton)-NMR analysis to be Ce(OSiMe ₃ ) ₃ and to be the cerium compound (M1) represented by the general formula (3). After that, 100 g of dimethylpolysiloxane having a viscosity of 100 mPa·s/23° C. was added with stirring, and xylene was volatilized and removed at 80° C. while reducing the pressure to 100 mmHg or less to replace the solvent. D), 102 g of a silicone dispersion of cerium compound (M1) (0.29% cerium content) was obtained.

As a heat resistance imparting agent (d1) as a comparative example, 10 g of a turpentine solution of a rare earth element salt of 2-ethylhexanoic acid containing cerium as a main component (rare earth element content: 6% by weight) and titanium tetra-normal butoxide (titanium content: 14% by weight) was mixed to form a mixed solution, and 100 g of dimethylpolysiloxane (viscosity: 100 mPa s/23°C) was added to the mixed solution while stirring, and heated to 200°C to obtain volatile matter (turpentine). removed. Next, the mixture was heated at 300° C. for 1 hour with stirring to obtain 100 g of heat resistance imparting agent (d1) (cerium content: 0.30%) as a brown transparent product.

<Examples and Comparative Examples>
As the ^{organovinylpolysiloxane} (A1), linear dimethylvinylpolysiloxane having both ends of the molecular chain blocked with MVi units, having a weight-average molecular weight of 114,000 and a silicon-bonded vinyl group content of 0.019 mmol/g. , as an ^{organovinylpolysiloxane} (A2), branched-chain dimethylvinylpolysiloxane having a weight-average molecular weight of 2,000 and a silicon-bonded vinyl group content of 1.7 mmol/g endblocked with terminal MVi units and containing Q units The siloxane, as organohydrogenpolysiloxane (B), is branched chain dimethyl with a weight average molecular weight of 1,500 and a silicon-bonded hydrogen group content of 7.0 mmol/g, which is capped with terminal ^MH units and contains Q units. Hydrogen polysiloxane, platinum-vinyl dimer complex (platinum content 12% by weight) is used as the curing catalyst (C) necessary for the addition reaction, and the above cerium compound (M1) is used as the heat resistance imparting agent in the examples. The heat resistance imparting agent (D) was used as the heat resistance imparting agent of Comparative Example 1, and the heat resistance imparting agent (d1) was used as the heat resistance imparting agent of Comparative Example 2. The heat resistance imparting agent (d2): cerium oxide dispersion Needral B-10 (trade name, average primary particle size of cerium oxide: 8 nm, solvent: organic acid, manufactured by Taki Kagaku Co., Ltd.) was used as a heat resistance imparting agent in Comparative Example 3. Heat resistance imparting agent (d3): 2-ethyl Addition-type silicone resin compositions of Examples and Comparative Examples were obtained using cerium hexanoate (cerium content: 12% by weight, manufactured by Aldrich) with the formulations shown in Table 1.

^MVi unit: ( _CH3 ) ₂ ( _CH2 =CH) _SiO1/2
M ^H unit: ( _CH3 ) _{2HSiO1/ 2}
Q unit: SiO _4/2

<Evaluation items and evaluation methods>

<Durometer hardness>
The addition-type silicone resin compositions of Examples and Comparative Examples were poured into a mold of 40 mm×60 mm×4 mm (thickness) and cured at 150° C. for 4 hours to prepare specimens with a thickness of 4 mm. The initial durometer hardness was measured at 23° C. using a type A durometer in accordance with JIS K6253-3 (vulcanized rubber and thermoplastic rubber-determination of hardness-part 3: durometer hardness). After that, it was allowed to stand at a high temperature of 250° C. for 100 hours and 200 hours, and after slowly cooling to 23° C., the durometer hardness was similarly measured. 65 or less was evaluated as good.

<Weight change rate>
The addition-type silicone resin compositions of Examples and Comparative Examples were poured into a mold of 40 mm x 60 mm x 4 mm (thickness) and cured at 150°C for 4 hours to prepare a test specimen with a thickness of 4 mm, which was slowly cooled to 23°C. and measure the initial weight. After that, it is left at a high temperature of 250° C. for 100 hours and 200 hours, slowly cooled to 23° C., and after heating, the weight is measured. The value obtained by dividing the weight after heating by the initial weight and multiplying by 100 was calculated as the weight change rate (%). A weight change rate of 90% or more was evaluated as good.

<Yellowness>
The addition-type silicone resin compositions of Examples and Comparative Examples were poured into a mold of 40 mm × 60 mm × 4 mm (thickness), cured at 150°C for 4 hours to prepare a test specimen with a thickness of 4 mm, and slowly cooled at 23°C. Then, the b value was measured as a degree of yellowing with an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu Corporation). After that, it was allowed to stand at 250° C. for 100 hours and 200 hours, then slowly cooled to 23° C., and the b value after heating was similarly measured. A yellowing index of 1.5 or less was judged to be good.

<Transmittance>
The addition-type silicone resin compositions of Examples and Comparative Examples were poured into a mold of 40 mm × 60 mm × 4 mm (thickness), cured at 150°C for 4 hours to prepare a test specimen with a thickness of 4 mm, and slowly cooled at 23°C. Then, the transmittance (wavelength: 450 nm) was measured with an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-2450). After that, the film was allowed to stand at 250° C. for 100 hours and 200 hours, then slowly cooled to 23° C., and the transmittance after heating was similarly measured. A transmittance of 90% or more was judged to be good.

<crack>
The addition-type silicone resin compositions of Examples and Comparative Examples were poured into a mold of 40 mm x 60 mm x 4 mm (thickness) and cured at 150°C for 4 hours to prepare a test specimen with a thickness of 4 mm, which was slowly cooled to 23°C. Visually observe the presence or absence of cracks. After that, it was left at a high temperature of 250° C. for 100 hours and 200 hours, and after slowly cooling to 23° C., the presence or absence of cracks was visually observed in the same manner. No cracks were judged to be good.

<Evaluation results>
Table 2 shows the evaluation results.

Claims (2)

a linear dimethylvinylpolysiloxane (A1) having at least two silicon-bonded alkenyl groups that react with SiH groups in one molecule;
a branched-chain dimethylvinylpolysiloxane (A2) having at least two silicon-bonded alkenyl groups that react with SiH groups in one molecule;
an organohydrogenpolysiloxane (B) having at least two SiH groups in one molecule;
a curing catalyst (C) necessary for the addition reaction;
An addition-type silicone resin composition comprising a heat resistance-imparting agent (D),
The heat resistance imparting agent (D) is
a silazane compound (D1) represented by the following general formula (1);
^{R1R2R3SiNH ( R4R5SiNH ) nSiR6R7R8 ( 1 )} _{_}
(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different monovalent hydrocarbon groups, and n is 0 or an integer of 1 or more. )
cerium carboxylate (D2) represented by the following general formula (2),
( ^R9COO ) _mCe (2)
(In the formula, R ⁹ is a monovalent hydrocarbon group of the same or different type, and m is 3 or 4). (M1),
Ce( ^R12 )(R13) ^{( R14} ) ⁽ R15)n (3)
(wherein R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are —OSiR ¹⁶ R ¹⁷ R ¹⁸ , R ¹⁶ , R ¹⁷ and R ¹⁸ are the same or different monovalent hydrocarbon groups, n is 0 or 1)
An addition-type silicone resin composition comprising: An optical semiconductor device comprising a semiconductor element sealed with a cured product of the addition-type silicone resin composition according to claim 1 .