JP2019052198A - Heat-resistant condensation-curable silicone resin composition and optical semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have heat resistance and prevent deterioration and cracks even when placed in a high temperature for a long time, and as a result, when used as an LED encapsulant, condensation having heat resistance with little decrease in LED brightness. A curable silicone resin composition and an optical semiconductor device using the same are provided. SOLUTION: An organopolysiloxane (A) having at least two hydrolyzable groups bonded to a silanol group or a silicon atom, and a silane compound having two or more alkoxy groups bonded to a silicon atom in one molecule ( A heat-resistant condensation-curable silicone resin composition comprising B), a silanol condensation catalyst (C), and a rare earth-containing organopolysiloxane compound as a heat resistance-imparting agent (D). This is the optical semiconductor device used. [Selection diagram] None

Description

  TECHNICAL FIELD The present invention relates to a condensation-curable silicone resin composition having heat resistance, which does not deteriorate even when placed at a high temperature for a long period of time and does not generate cracks, and an optical semiconductor device using the same.

  Conventionally, a silanol condensation catalyst, a heat-curable silicone resin composition for encapsulating a photo-semiconductor, and a photo-semiconductor encapsulant using the same, which have excellent heat-resistant coloring stability and thin film curability and can suppress heat loss, have been proposed. (Patent Document 1). The silicone resin composition has (A) 100 parts by mass of polysiloxane having two or more silanol groups in one molecule, and (B) two or more alkoxy groups bonded to silicon atoms in one molecule. It is a thermosetting silicone resin composition for encapsulating an optical semiconductor containing 0.1 to 2000 parts by mass of a silane compound and (C) a zirconium metal salt represented by the formula (I) in Patent Document 1.

  However, when the silicone resin composition is left at a high temperature of about 250 ° C. for a long time, the cured product may be cracked and used as a sealant for an optical semiconductor element (hereinafter referred to as LED). Then, there exists a subject that the brightness | luminance of this LED may fall.

JP 2010-163602 A

  The problem to be solved by the present invention is that it has heat resistance and is not deteriorated even when placed under high temperature for a long time, so that cracks do not occur. An object of the present invention is to provide a condensation-curable silicone resin composition having low heat resistance and an optical semiconductor device using the same.

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that polydimethylsiloxane (A) whose molecular chain ends are blocked with a hydroxyl group and two or more alkoxy groups bonded to a silicon atom in one molecule. As a silane compound (B), a silanol condensation catalyst (C), and a heat resistance imparting agent (D),
An organopolysiloxane (D1) having a viscosity at 25 ° C. of 10 to 10,000 mPa · s;
Cerium carboxylate represented by the general formula (R ₁ COO) _n M (R ₁ is the same or different monovalent hydrocarbon group, M is a rare earth element mixture mainly composed of cerium, n = 3 or 4) D2)
A titanium compound (D3) represented by the general formula (R ₂ O) ₄ Ti (R ₂ is the same or different monovalent hydrocarbon group);
A rare earth-containing organopolysiloxane compound obtained by heat treatment at a temperature of 250 ° C. or higher;
A condensation-curable silicone resin composition having heat resistance is provided.

  According to a second aspect of the present invention, there is provided an optical semiconductor device, wherein the optical semiconductor element is sealed with the cured product of the first aspect.

  The heat-resistant condensation-curable silicone resin composition of the present invention has the effect that there is no decrease in physical properties and no occurrence of cracks even when placed at a high temperature for a long time, resulting in a decrease in LED brightness. There is no effect. The optical semiconductor device according to claim 2 has an effect that there is no decrease in luminance as a result.

  Hereinafter, the heat-resistant condensation-curable silicone resin composition according to the present invention will be specifically described.

<Polydimethylsiloxane (A) whose molecular chain ends are blocked with hydroxyl groups>
The organopolysiloxane (A) having at least two hydrolyzable groups bonded to silanol groups or silicon atoms used in the present invention gives an appropriate fluidity to the present composition before curing, and the rubber after curing. It is blended in order to give excellent mechanical properties to the elastic body, and the viscosity at 25 ° C. is desirably 0.01 to 1000 Pa · s. When the viscosity is less than 0.01 Pa · s, the mechanical properties of the rubber-like elastic body after curing are insufficient, and when it exceeds 1000 Pa · s, it is difficult to obtain a uniform composition and the fluidity is deteriorated. More preferably, the viscosity at 25 ° C. is 0.1 to 100 Pa · s. If it is less than 0.1 Pa · s, there is a tendency that the mechanical properties of the rubber-like elastic body after curing tend to be inadequate, and uniform above 100 Pa · s. Tend to be difficult to obtain, and fluidity tends to be poor. Examples of the hydrolyzable group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group.

  As an organic group directly bonded to a silicon atom, a methyl group is preferable because of easy synthesis, but other alkyl groups such as methyl, ethyl, propyl, butyl and hexyl, alkenyl groups such as vinyl and allyl, and chloromethyl Group, a monovalent substituted hydrocarbon group such as β-cyanoethyl group, 3,3,3-trifluoropropyl group, or the like may be bonded thereto.

  In particular, the methyl group is not only easily obtained as a raw material intermediate, but also has a low viscosity even when the degree of polymerization of the siloxane is high, and the balance between the fluidity of the composition before curing and the physical properties of the rubber-like elastic body after curing. Is good. Even when the other organic groups are bonded, 85% or more of the total organic groups are preferably methyl groups.

<Silane compound (B) having two or more alkoxy groups bonded to silicon atoms in one molecule>
The silane compound (B) having two or more alkoxy groups bonded to silicon atoms in one molecule used in the present invention has one silicon atom in one molecule, and two alkoxy groups in the silicon atom. An organopolysiloxane compound having two or more silicon atoms in one molecule, a skeleton of a polysiloxane skeleton, and two or more alkoxy groups bonded to silicon atoms, Either may be used, but the former silane compound (B) is preferable.

  Examples of the silane compound having one silicon atom in one molecule and two or more alkoxy groups bonded to the silicon atom include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, Dialkoxysilanes such as diphenyldimethoxysilane, diphenyldiethoxysilane; trialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane Tetraalkoxysilane such as tetramethoxysilane, tetraethoxysilane, tetraisopropyloxysilane; trialkoxysilane, hydrolyzate of tetraalkoxysilane; γ- (meth) acrylo Shi trimethoxysilane, .gamma. (meth) acryloxy propyl, such as triethoxy silane (meth) acryloxy sialic quilt trialkoxysilane can be cited.

<Silanol condensation catalyst (C)>
The silanol condensation catalyst (C) used in the present invention includes tin octylate, tin neodecanoate, tin naphthenate, tin stearate, dibutyltin dioctoate, dibutyltin dilaurate, dioctyltin diversate, dibutyltin bistriethoxysilicate, dibutyltin Rail malate, dibutyltin diacetate, 1,1,3,3-tetrabutyl-1,3-dilauryloxycarbonyl-distannoxane, dibutyltin oxybisethoxysilicate, dibutyltin oxide, dioctyltin salt and orthoethyl silicate Reaction products, reaction products of dibutyltin salt and orthoethyl silicate, reaction products of dibutyltin oxide and phthalate, reaction products of dibutyltin oxide and maleic diester, dibutyltin diacetylacetonate, etc. Organotin compounds And the like. By using such a silanol condensation catalyst (C), the internal curability of the composition is improved.

  The amount of (C) in the silanol condensation catalyst is 0.1 to 1.0 part by weight per 100 parts by weight of component (A), and if it is less than 0.1 part by weight, the curing rate may be slow. If it exceeds 0.0 parts by weight, the pot life may be shortened. As a commercially available tin stearate, there is Neostan U-50 (manufactured by Nitto Kasei Co., Ltd., trade name).

<Heat resistance imparting agent (D)>
The heat resistance imparting agent (D) used in the present invention is composed of an organopolysiloxane (D1) having a viscosity at 25 ° C. of 10 to 10,000 mPa · s and a general formula (R ₁ COO) _n M (R ₁ is the same or different. A monovalent hydrocarbon group, M is a rare earth element mixture mainly composed of cerium, cerium carboxylate (D2) represented by n = 3 or 4), and a general formula (R ₂ O) ₄ Ti (R ₂ is It is a rare earth-containing organopolysiloxane compound obtained by heat-treating a titanium compound (D3) represented by the same or different monovalent hydrocarbon group) at a temperature of 250 ° C. or higher.

  The organopolysiloxane (D1) may be any conventionally known organopolysiloxane having a viscosity of 10 to 10,000 mPa · s at 25 ° C., which is substantially composed of repeating diorganopolysiloxane units (linear structure). It is a straight-chain or branched one that keeps liquid at room temperature. The organic group bonded to the 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, or a butyl group; a vinyl group, an allyl group An alkenyl group such as a phenyl group or a tolyl group; a cycloalkyl group such as a cyclohexyl group; or a group in which part or all of the hydrogen atoms bonded to these carbon atoms are substituted with a halogen atom, a cyano group, or the like; For example, it is selected from chloromethyl group, fluoropropyl group, cyanomethyl group and the like. As the organopolysiloxane (D1), the molecular chain terminal is 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 trivinyl Examples thereof include those blocked with a triorganosiloxy group such as a trialkenylsiloxy group such as a siloxy group, a hydroxyl group or an alkoxy group. Moreover, the mixture of these various organopolysiloxane may be sufficient. The viscosity of the organopolysiloxane (D1) component is 10 to 10000 mPa · s, preferably 50 to 1000 mPa · s at 25 ° C. When the viscosity is 10 mPa · s or less, the amount of siloxane evaporation at a high temperature tends to increase and the weight change increases, so the heat resistance tends to decrease. On the other hand, when it exceeds 10,000 mPa · s, mixing with a cerium compound, which will be described later, is not performed smoothly, so that the heat resistance is likely to be lowered.

The carboxylic acid salt of cerium as the component (D2) has the general formula:
(R ₁ COO) _n M
Where R ₁ is the same or different monovalent hydrocarbon group, M is a rare earth element mixture mainly composed of cerium, 2-ethylhexanoic acid, naphthenic acid, oleic acid, lauric acid, stearin Illustrative are cerium salts such as acids. The cerium carboxylate is preferably used as an organic solvent solution from the viewpoint of ease of handling and compatibility with titanium of the following component (D3). Examples of the organic solvent include standard solvent, Examples thereof include petroleum solvents such as mineral spirit, ligroin and petroleum ether, and aromatic solvents such as toluene and xylene.

  The amount of component (D2) added is polydimethyl, the cerium content of which constitutes the condensation curable silicone resin composition in which the heat resistance imparting agent of the present invention is blended, and whose molecular chain ends are blocked with hydroxyl groups. The amount of 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of siloxane (A). When the amount of cerium is less than 0.05 parts by weight, the expected heat resistance cannot be obtained. On the other hand, when the amount is more than 5 parts by weight, the cerium compound becomes non-uniform in the polydimethylsiloxane (A) component, and the predetermined heat resistance cannot be obtained.

The titanium compound as the component (D3) has the general formula:
(R ₂ O) ₄ Ti
Indicated by Here, each R ₂ is independently a monovalent hydrocarbon group, preferably an alkyl having 1 to 30 carbon atoms such as an isopropyl group, n-butyl group, stearyl group, octyl group, etc., preferably 1 to 20 carbon atoms. And Ti is titanium. Such a compound is exemplified by tetraalkoxytitanium, but may be a partially hydrolyzed condensate thereof.

  The heat resistance imparting agent (D) according to the present invention is obtained by heat treatment at a temperature of 250 ° C. or higher after mixing the components (D1) to (D3), and the heating temperature is less than 250 ° C. Then, it is difficult to obtain a uniform composition, and if it exceeds 310 ° C., the thermal decomposition rate of the component (D1) increases, so it is preferable to treat at 250 to 310 ° C.

  The heat resistance-imparting agent of the present invention is 0.2 to about 100 parts by weight of polydimethylsiloxane (A) whose molecular chain terminal is blocked with a hydroxyl group as a component constituting the condensation curable silicone resin composition. It is preferable to add 5 parts by weight, and more preferably 0.5 to 4 parts by weight. When the addition amount of the heat resistance imparting agent according to the present invention is less than 0.2 parts by weight, the effect of improving the heat resistance at high temperature is not seen. It becomes difficult to obtain the effect.

  The structure of the rare earth-containing organopolysiloxane compound is such that the cerium carboxylate (D2) before the heat treatment is a carboxylate of a mixture of rare earth elements mainly composed of cerium, and the rare earth-containing organopolysiloxane obtained by the heat treatment. Since the siloxane compound is not a simple substance, it is difficult to isolate and identify each trace component, and it is impossible to identify it by its structure. Moreover, it is difficult to separate the rare earth-containing organoorganopolysiloxane as a mixture, and the rare earth-containing organopolysiloxane compound obtained by heat treatment cannot be directly specified by its characteristics. Therefore, the rare earth-containing organopolysiloxane compound has a situation where it is impossible or almost impractical to “directly identify the product by its structure or characteristics at the time of filing”.

<Silicone oil>
A silicone oil can be mix | blended with this invention as needed. Silicone oil is blended for the purpose of improving workability when using the present composition, improving foam removal properties, etc., and adjusting the hardness and elongation of the rubber-like elastic body after curing. Silicone oil is a non-reactive silicone oil that does not have a reactive group such as an alkoxy group or silanol group in the molecule, and the end of the molecular chain is blocked with a triorganosiloxy group such as a trimethylsiloxy group. Most preferably used is polydimethylsiloxane blocked at both ends with trimethylsiloxy groups.

  The viscosity of the silicone oil is preferably 5 to 50,000 mPa · s at 25 ° C., and if it is less than 5 mcSt, the mechanical properties of the rubber-like elastic body after curing of the composition may be insufficient. If it exceeds 000 mPa · s, the fluidity of the composition may deteriorate. More preferably, it is 50 to 5,000 mP · s, and if it is less than 50 mP · s, the mechanical properties of the rubber-like elastic body after curing of the composition tend to be insufficient, and if it exceeds 5,000 mPa · s, There exists a tendency for the extrusion workability | operativity of a composition to worsen.

  The compounding quantity of silicone oil is 0.1-100 weight part per 100 weight part of said (A) component, Preferably it is 0.2-80 weight part. If it is less than 0.1 part by weight, the fluidity of the composition is insufficient, and if it exceeds 100 parts by weight, the mechanical strength of the cured product is lowered. If it is less than 0.2 parts by weight, the extrusion workability of the composition tends to be insufficient, and if it exceeds 80 parts by weight, the mechanical strength of the cured product tends to decrease.

  According to a second aspect of the present invention, an optical semiconductor device such as an optical semiconductor (LED) is sealed with a cured product of the heat-resistant condensation-curable silicone resin composition according to the first aspect. It is an optical semiconductor device.

  Hereinafter, it demonstrates concretely in an Example and a comparative example.

<Preparation of heat resistance imparting agent (D)>
As an organopolysiloxane (D1) having a viscosity of 10 to 10,000 mPa · s at 25 ° C., a linear dimethylpolysiloxane having both ends sealed with trimethylsiloxy groups and having a viscosity of 100 mP · s / 25 ° C. As cerium carboxylate (D2), 2-ethylhexanoic acid rare earth terpene solution rare earth OCTOATE 6% (rare earth element content 6% by weight, manufactured by DIC), titanium compound (D3) as titanium tetra Using normal butoxide (titanium content 14% by weight), the components (D2) and (D3) were mixed in the formulation shown in Table 1, and the mixture was added to the component (D1) with stirring. Thereafter, the terpene was volatilized by heating while circulating nitrogen gas. Then, it heated at 300 degreeC for 1 hour, stirring, and prepared the brown and transparent heat resistance imparting agent (D).

<Examples and Comparative Examples>
In the formulation shown in Table 2, polydimethylsiloxane in which both molecular chain ends with a viscosity of 3 Pa · s / 25 ° C. are blocked with hydroxyl groups is used as the component (A), and tetraethoxysilane is used as the silane compound (B). Polydimethylsiloxane having both ends of a viscosity of 0.1 Pa · s / 25 ° C. blocked with a trimethylsiloxy group is used as a silicone oil, and Neostan U-50 (manufactured by Nitto Kasei Co., Ltd., trade name) as a silanol condensation catalyst (C). ), And using the heat resistance imparting agent (D) prepared as described above as the heat resistance imparting agent (D), all the materials are uniformly mixed, and the condensation curable type of Example or Comparative Example A silicone resin composition was obtained.

<Evaluation items and evaluation methods>

<Durometer hardness>
The condensation curable silicone resin compositions of Examples and Comparative Examples are poured into a container having a diameter of 3 cm, and left in an atmosphere of 23 ° C. and 50% RH for 7 days to produce a cured product having a thickness of 10 mm. This hardness was measured with a type A durometer as defined in JIS K 6253, and used as the initial durometer hardness. Thereafter, the cured product was allowed to stand in an oven at 250 ° C. for 100 hours and 200 hours, gradually cooled to 23 ° C. after each time, and the durometer hardness was measured in the same manner.

<Weight change rate>
The condensation curable silicone resin compositions of Examples and Comparative Examples are poured into a container having a diameter of 3 cm, and left in an atmosphere of 23 ° C. and 50% RH for 7 days to produce a cured product having a thickness of 10 mm. This weight is measured and used as the initial weight. Thereafter, the cured product is left in an oven at 250 ° C. for 100 hours and 200 hours, gradually cooled to 23 ° C. after the passage of each time, and the weight is measured to obtain the weight after heating. A value obtained by dividing a value obtained by subtracting the initial weight from the weight after heating by the initial weight was calculated as a weight change rate (%).

<Crack>
The condensation curable silicone resin compositions of Examples and Comparative Examples are poured into a container having a diameter of 3 cm, and left in an atmosphere of 23 ° C. and 50% RH for 7 days to produce a cured product having a thickness of 10 mm. Thereafter, the cured product was allowed to stand in an oven at 250 ° C. for 100 hours and 200 hours, and it was visually confirmed whether or not cracks had occurred in the cured product after each time.

<Evaluation results>
The evaluation results are shown in Table 3.

Claims (2)

An organopolysiloxane (A) having at least two hydrolyzable groups bonded to silanol groups or silicon atoms, and a silane compound (B) having two or more alkoxy groups bonded to silicon atoms in one molecule; As a silanol condensation catalyst (C) and a heat resistance imparting agent (D),
An organopolysiloxane (D1) having a viscosity at 25 ° C. of 10 to 10,000 mPa · s;
Cerium carboxylate represented by the general formula (R ₁ COO) _n M (R ₁ is the same or different monovalent hydrocarbon group, M is a rare earth element mixture mainly composed of cerium, n = 3 or 4) D2)
A titanium compound (D3) represented by the general formula (R ₂ O) ₄ Ti (R ₂ is the same or different monovalent hydrocarbon group);
A rare earth-containing organopolysiloxane compound obtained by heat treatment at a temperature of 250 ° C. or higher;
A condensation-curable silicone resin composition having heat resistance, comprising: An optical semiconductor device, wherein an optical semiconductor element is sealed with the cured product according to claim 1.