JP2011032392A - Silicone resin composition for optical semiconductor devices - Google Patents

Abstract

Provided is a silicone resin composition for an optical semiconductor device that provides a cured product excellent in strength, whiteness, heat resistance and light resistance after curing.
(A) 100 parts by mass of an organopolysiloxane of the following average composition formula (1) (CH ₃ ) _a Si (OR ¹ ) _b (OH) _c O _{(4-abc) / 2} (1) (R ¹ Is a monovalent hydrocarbon group having 1 to 4 carbon atoms, 0.8 ≦ a ≦ 1.5, 0 ≦ b ≦ 0.3, 0.001 ≦ c ≦ 0.5, and 0.801 ≦ a + b + c <2. (B) 3 to 200 parts by weight of white pigment other than the following (C) (C) 60 to 80% by weight of spherical silica having an average particle size of 0.2 to 40 μm and crushed silica 20 to 20 μm having an average particle size of 5 to 10 μm 400 to 1000 parts by weight of an inorganic filler having an average particle diameter of 10 to 40 μm comprising 40% by weight (D) 0.01 to 10 parts by weight of a condensation catalyst (E)-[— (R ₂ ) Si (R ₃ ) —O -]-A composition containing 2 to 50 parts by mass of an organopolysiloxane having a linear diorganopolysiloxane residue represented by .
[Selection figure] None

Description

  The present invention relates to a silicone resin composition for an optical semiconductor device, and more specifically includes an organopolysiloxane having a silanol group and an organopolysiloxane having a linear diorganopolysiloxane residue of a predetermined length. The present invention relates to a silicone resin composition that is excellent in moldability and discoloration due to photodegradation of a cured product and excellent in the strength of the molded product.

  Optical semiconductor elements such as LEDs (Light Emitting Diodes) are used as various indicators and light sources. 2. Description of the Related Art In recent years, there has been a problem that optical output is reduced due to, for example, a resin material used in the periphery of an optical semiconductor element being light-degraded and yellowing due to progress of higher output and shorter wavelength of an optical semiconductor device.

  As a resin composition for encapsulating an optical semiconductor, an epoxy resin composition for encapsulating a B-stage optical semiconductor having an epoxy resin, a curing agent and a curing accelerator as constituent components is known (Patent Document 1). Patent Document 1 discloses that bisphenol A type epoxy resin or bisphenol F type epoxy resin is mainly used as an epoxy resin, and triglycidyl isocyanate or the like can be used. However, the composition has a problem of yellowing due to photodegradation, and this problem occurs particularly when the semiconductor element is lit at a high temperature or lit for a long time.

  As a sealing material epoxy resin composition for a light-emitting element excellent in heat resistance and light resistance, one containing an isocyanuric acid derivative epoxy resin (Patent Document 2) is known. However, the composition is not sufficient in terms of light resistance.

A resin composition for sealing an LED element is known that contains an organopolysiloxane having a weight average molecular weight of 5 × 10 ² or more and excellent condensation resistance and a condensation catalyst (Patent Document 3). However, the composition is not a use using a white pigment such as a reflector, but a resin composition for a use requiring higher transparency.

  Moreover, when a white pigment or silica is used for each of the silicone resin compositions, the strength after molding becomes low, and the occurrence of cracks becomes a problem in the subsequent steps. The above silicone resin compositions are not satisfactory in this respect.

Japanese Patent Laid-Open No. 02-189958 JP 2005-306952 A JP 2006-77234 A

  Accordingly, an object of the present invention is to provide a silicone resin composition for an optical semiconductor device that provides a cured product that is excellent in strength after curing and that has excellent whiteness, heat resistance, and light resistance.

（Ｒ^２及びＲ^３は、互いに独立に、炭素数１〜３のアルキル基、シクロヘキシル基、ビニル基、フェニル基及びアリル基から選ばれる基であり、ｍは５〜５０の整数である） The present invention is a silicone resin composition comprising:
(A) 100 parts by mass of an organopolysiloxane represented by the following average composition formula (1) and having a weight average molecular weight (in terms of polystyrene) of 500 to 20000

(CH ₃ ) _a Si (OR ¹ ) _b (OH) _c O _{(4-abc) / 2} (1)

(In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a, b and c are 0.8 ≦ a ≦ 1.5, 0 ≦ b ≦ 0.3, 0.001 ≦ (c ≦ 0.5 and 0.801 ≦ a + b + c <2)
(B) White pigment other than the following (C) 3 to 200 parts by mass (C) Inorganic filler other than the white pigment, 60 to 80% by weight of spherical silica having an average particle size of 0.2 to 40 μm and an average particle size Inorganic filler consisting of 20 to 40% by weight of crushed silica of 5 to 10 μm and having an average particle diameter of 10 to 40 μm 400 to 1000 parts by weight (D) Condensation catalyst 0.01 to 10 parts by weight (E) The following formula (2) 2-50 parts by mass of an organopolysiloxane having a linear diorganopolysiloxane residue represented by

(R ² and R ³ are each independently a group selected from an alkyl group having 1 to 3 carbon atoms, a cyclohexyl group, a vinyl group, a phenyl group, and an allyl group, and m is an integer of 5 to 50)

The composition of the present invention is cured without distorting the apparatus by a combination of an organopolysiloxane (E) having a linear diorganopolysiloxane residue of a predetermined length and a branched organopolysiloxane (A). Further, by containing an inorganic filler having a predetermined average particle diameter, a cured product having strength can be provided.

FIG. 1 is a cross-sectional view showing an example of an optical semiconductor device using the silicone resin composition of the present invention.

(A) Organopolysiloxane (A) Organopolysiloxane has silanol groups and (D) forms a crosslinked structure in the presence of a condensation catalyst. In the average composition formula (1), R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms. a, b and c are 0.8 ≦ a ≦ 1.5, 0 ≦ b ≦ 0.3, 0.001 ≦ c ≦ 0.5, 0.801 ≦ a + b + c <2, preferably 0.8. 911 ≦ a + b + c ≦ 1.8, more preferably 1.0 ≦ a + b + c ≦ 1.5.

  In the formula (1), a is 0.8 ≦ a ≦ 1.5, preferably 0.9 ≦ a ≦ 1.2, and more preferably 0.9 ≦ a ≦ 1.1. If a is less than the above lower limit, the cured product of the resin composition is too hard and may cause cracks and the like, and is not preferred if the upper limit is exceeded, since the resin composition does not solidify.

In formula (1), b is 0 ≦ b ≦ 0.3, preferably 0.001 ≦ b ≦ 0.2, and more preferably 0.01 ≦ b ≦ 0.1. If b exceeds the above upper limit, the molecular weight may be small and the crack prevention performance may be insufficient. The OR ¹ group in the compound can be quantified by an infrared absorption spectrum (IR), an alcohol quantification method by alkali cracking, or the like.

  In formula (1), c is 0.001 ≦ c ≦ 0.5, preferably 0.01 ≦ c ≦ 0.3, and more preferably 0.05 ≦ c ≦ 0.2. If c exceeds the above upper limit value, the condensation reaction at the time of heat curing and / or the condensation reaction with the component (E) will give a hardened product with high hardness and poor crack resistance. If c is less than the above lower limit value, the melting point tends to be high, and there may be a problem in workability. Furthermore, when there is no bond formation with the component (E), the hardness of the cured product is lowered and the solvent resistance is reduced. Since it tends to be worse, it is not preferable. In order to control c within the above range, it is preferable that the complete condensation rate of the alkoxy group of the raw material is 86 to 96%. If it is less than the above lower limit, the melting point becomes low, and if it exceeds the above upper limit, the melting point becomes too high, which is not preferable.

In the above formula (1), R ¹ is the same or different monovalent hydrocarbon group having 1 to 4 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, an isopropyl group, an n-butyl group, or a vinyl group. And an alkenyl group such as an allyl group. Of these, a methyl group and an isopropoxy group are preferred because the raw materials are easily available.

  (A) Organopolysiloxane has a weight average molecular weight of 500 to 20000, preferably 1000 to 10000, more preferably 2000 to 8000, in terms of polystyrene standard measured by GPC. If the molecular weight is less than the lower limit, the resin composition is difficult to solidify, and if the molecular weight exceeds the upper limit, the viscosity of the resin composition increases and the fluidity decreases.

The component (A) can be generally expressed by a combination of Q unit (SiO ₂ ), T unit (CH ₃ SiO _1.5 ), and D unit ((CH ₃ ) ₂ SiO). In the formula, the ratio of the number of moles of T units to the total number of moles of all siloxane units is 70 mol% or more, preferably 75 mol% or more, particularly preferably 80 mol% or more. If the T unit is less than the above lower limit value, the overall balance of hardness, adhesion, and appearance may be lost. The D and Q units are preferably 30 mol% or less based on the total number of moles of all siloxane units. As the proportion of D and Q units increases, the melting point of the resin composition tends to increase.

The component (A) can be obtained as a hydrolytic condensate of organosilane represented by the following general formula (3).
[Chemical formula 3]
(CH ₃ ) _n SiX _4-n (3)
(Wherein X is a halogen atom or an alkoxy group having 1 to 4 carbon atoms, n is 1, 2 or 0, and X is preferably a halogen atom, particularly a chlorine atom.)

  Examples of the silane compound represented by the above formula (3) include methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, tetrachlorosilane, tetramethoxylane, Examples include tetraethoxylane.

  Hydrolysis condensation of the above organosilane can be performed by a known method, and is performed in the presence of an acid catalyst such as acetic acid, hydrochloric acid or sulfuric acid, or an alkali catalyst such as sodium hydroxide, potassium hydroxide or tetramethylammonium hydroxide. It is preferable. When a silane containing a chlorine group is used as a hydrolyzable group, a desired hydrolysis condensate having an appropriate molecular weight can be obtained using hydrochloric acid generated by water addition as a catalyst.

  The amount of water added in the hydrolysis condensation is usually 0.9 to 1.6 mol, preferably 1.0 to 1.3 per mol of the total amount of hydrolyzable groups in the organosilane. Is a mole. Within the above range, an organopolysiloxane excellent in workability can be obtained, and the toughness of the cured product is excellent.

  In general, the hydrolysis-condensation is preferably performed in combination with an organic solvent such as alcohols, ketones, esters, cellosolves, and aromatic compounds. As the organic solvent, alcohols such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, n-butanol, and 2-butanol are preferable, and toluene and xylene are preferable as the aromatic compound. Among them, use of isopropyl alcohol and toluene is excellent in curability. An organopolysiloxane is provided, and the toughness of the cured product is excellent, which is preferable.

  The reaction temperature for the hydrolysis condensation is preferably 10 to 120 ° C, more preferably 20 to 100 ° C. As long as the reaction temperature falls within the range, a solid organopolysiloxane having excellent workability can be obtained without gelation.

As the hydrolysis condensation, for example, when performing hydrolysis condensation using methyltrichlorosilane, water and isopropyl alcohol are added to methyltrichlorosilane dissolved in toluene, and partial hydrolysis (reaction temperature -5 ° C to 100 ° C) is performed. Then, a solid silicone polymer having a melting point of 76 ° C. represented by the following formula (4) is obtained by adding and reacting with an amount of water in which the total amount of the remaining chlorine groups is hydrolyzed.
[Chemical formula 4]
(CH ₃ ) _a Si (OC ₃ H ₇ ) _b (OH) _c O _{(4-abc) / 2} (4)
(Wherein a, b and c are as described above.)

Examples of the average composition formula (4) include the following formulas (5) and (6).
[Chemical formula 5]
(CH ₃ ) _1.0 Si (OC ₃ H ₇ ) _0.07 (OH) _0.13 O _1.4 (5)

(CH ₃ ) _1.1 Si (OC ₃ H ₇ ) _0.06 (OH) _0.12 O _1.3 (6)

(B) White pigment (B) The white pigment is blended to make the cured product white for uses such as a reflector (reflector) of an optical semiconductor device. As the white pigment (white colorant), titanium dioxide, alumina, zircon oxide, zinc sulfide, zinc oxide, magnesium oxide and the like can be used alone or in combination with titanium dioxide. Of these, titanium dioxide, magnesium oxide, and alumina are preferable, and titanium dioxide is more preferable. The crystal form of titanium dioxide may be any of the rutile type, anatase type, and brookite type, but the rutile type is preferably used.

The white pigment preferably has an average particle size of 0.05 to 10 μm, more preferably 0.1 to 10 μm. Further, the white pigment may be surface-treated in advance with a hydroxide such as Al or Si in order to improve the mixing property and dispersibility with the resin components (A) and (E) or the inorganic filler (C). . The average particle size can be determined as a mass average value D ₅₀ in the particle size distribution measurement by laser diffraction method (or median diameter).

  The compounding amount of the white pigment is 3 to 200 parts by mass, preferably 5 to 170 parts by mass, and particularly preferably 10 to 140 parts by mass with respect to 100 parts by mass of the component (A). If it is less than the lower limit, sufficient whiteness may not be obtained, and the reflectivity of the cured product is 70% or more as the initial reflectivity, and the reflectivity after the deterioration test after heating for 24 hours at 180 ° C. is 70%. The above physical properties are difficult to obtain. Moreover, if it exceeds the upper limit, the proportion of the inorganic filler (C) added for the purpose of improving the mechanical strength decreases, which is not preferable. The amount of the white pigment may be 1 to 50% by mass, preferably 5 to 30% by mass, and more preferably 10 to 30% by mass with respect to the entire silicone resin composition.

(C) Inorganic filler (C) The inorganic filler is a filler other than the white pigment. As this filler, what is normally mix | blended with an epoxy resin composition can be used. Examples thereof include silicas such as fused silica and crystalline silica, silicon nitride, aluminum nitride, boron nitride, and antimony trioxide. In particular, fused silica and fused spherical silica are preferable, and it is preferable that the average particle size is 10 μm or more and 40 μm or less, and particles containing 90 μm or more are not contained. The average particle size can be determined as a mass average value D ₅₀ (or median diameter) in particle size distribution measurement by laser diffraction method. In order to maintain the strength of the molded product, it is preferable to contain crushed silica.

  The inorganic filler of the present invention is composed of 60 to 80% by weight of spherical silica having an average particle diameter of 0.2 to 40 μm and 20 to 40% by weight of crushed silica having an average particle diameter of 5 to 10 μm. An inorganic filler is desirable. Among these, spherical silica 60 comprising 0 to 15% by weight of spherical silica having an average particle size of 3 μm or less, 10 to 30% by weight of spherical silica having an average particle size of 4 to 8 μm, and 60 to 90% by weight of spherical silica having an average particle size of 10 to 40 μm. Those composed of ˜80 wt% and 20-40 wt% of crushed silica having an average particle diameter of 5-10 μm are preferred. When crushed silica is contained in this proportion, the strength of the cured product is improved. If it is less than the above lower limit value, the effect of improving the strength of the cured product is not obtained, and if it exceeds the above upper limit value, the fluidity is lowered.

(C) The inorganic filler has a rosin-Rammler n value of 0.7 to 0.9 measured by combining the components (B) and (C), and the correlation coefficient of the regression line is 0.99. In the following, it is preferable that the particle size distribution is 0.96 or more and 0.99 or less. The method for measuring the n-value and the correlation coefficient of the rosin-ramler equation is to put the data of the average particle diameters of the component (B) and the component (C) into the rosin-ramler equation represented by the following equation, and the rosin-ramler line. The graph is converted into a diagram, a regression line from the maximum particle size to the particle size of 1 μm is drawn, and the slope of the straight line (n value) and the correlation coefficient of the regression line are calculated.
R (Dp) = 100 · exp (−b · Dpn)
(Where Dp is the particle size, R (Dp) is the cumulative weight% from the maximum particle size to Dp, and n and b are constants.)

The average particle size of the inorganic filler is 10 to 40 μm, preferably 14 to 25 μm. Inorganic fillers having an average particle size of less than 10 μm, or inorganic fillers having a correlation coefficient of a rosin-Rammler regression line of more than 0.99 are not preferable because the fluidity of the resin composition is lowered. In order to highly fill the inorganic filler, it is necessary to use an inorganic filler having a particle size distribution in which the n value of the rosin-Rammler type is 0.7 or more and 0.9 or less, preferably 0.85 or more and 0.9 or less. At this time, high fluidity in the resin composition can be obtained. If the n value is less than the above lower limit value or exceeds the above upper limit value, sufficient fluidity cannot be obtained and the object of the present invention cannot be achieved.

  In order to increase the bonding strength between the resin and the inorganic filler, the inorganic filler may be blended with a surface treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent.

  Examples of such a coupling agent include epoxy functions such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Functional alkoxysilanes such as N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-mercapto It is preferable to use a mercapto functional alkoxysilane such as propyltrimethoxysilane. The amount of coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

  (C) As for the compounding quantity of an inorganic filler, 400-1000 mass parts with respect to 100 mass parts of (A) component, Especially 600-950 mass parts are preferable. If the amount is less than the above lower limit, sufficient strength may not be obtained, and if it exceeds 1000 parts by mass, unfilled mold failure due to thickening and flexibility will be lost, resulting in defects such as peeling in the element. There is a case. In addition, it is preferable that the total amount of (B) white pigment and (C) inorganic filler is 70 to 93% by mass, particularly 75 to 91% by mass of the entire silicone resin composition.

(D) Condensation catalyst (D) The condensation catalyst is a condensation catalyst for curing the component (A), and is selected in consideration of the storage stability of the component (A), the intended hardness, and the like. As the condensation catalyst, basic compounds such as trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, n-hexylamine, tributylamine, diazabicycloundecene (DBU), dicyandiamide; tetraisopropyl titanate, tetrabutyl titanate, Titanium acetylacetonate, aluminum triisobutoxide, aluminum triisopropoxide, zirconium tetra (acetylacetonate), zirconium tetrabutyrate, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin octet Rate, dibutyltin laurate, zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate, zinc laurate Metal-containing compounds such as zinc stearate, aluminum phosphate, aluminum triisopropoxide, aluminum trisacetylacetonate, aluminum bisethylacetoacetate / monoacetylacetonate, diisopropoxybis (ethylacetoacetate) titanium, diiso And organic titanium chelate compounds such as propoxybis (ethylacetoacetate) titanium. Of these, zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminum phosphate, and aluminum triisopropoxide are particularly preferable. Of these, zinc benzoate and organic titanium chelate compounds are preferably used.

  The compounding quantity of a curing catalyst is 0.01-10 mass parts with respect to 100 mass parts (A), Preferably it is 0.1-6 mass parts. Within this range, curability is good and the storage stability of the composition is also good.

ここで、Ｒ^２及びＲ^３は、互いに独立に、炭素数１〜３のアルキル基、シクロヘキシル基、ビニル基、フェニル基及びアリル基から選ばれる基であり、好ましくはメチル基及びフェニル基である。ｍは５〜５０、好ましくは８〜３０、より好ましくは１０〜２０の整数である。ｍが前記下限値未満では、硬化物の可撓性（耐クラック性）に乏しく、装置の反りを起こし得る。一方、前記上限値を超えては、機械的強度が不足する傾向がある。 (E) The organopolysiloxane (E) component has a linear diorganopolysiloxane residue represented by the following formula (2).

Here, R ² and R ³ are each independently a group selected from an alkyl group having 1 to 3 carbon atoms, a cyclohexyl group, a vinyl group, a phenyl group and an allyl group, preferably a methyl group and a phenyl group. . m is an integer of 5-50, preferably 8-30, more preferably 10-20. When m is less than the lower limit, the cured product is poor in flexibility (crack resistance) and may cause warping of the apparatus. On the other hand, when the upper limit is exceeded, the mechanical strength tends to be insufficient.

In addition to the R ² R ³ SiO ₁ unit, the component (E) includes D units (R ₂ SiO ₁ ), M units (R ₃ SiO _0.5 ), T units (RSiO _1.5 ) where m is outside the range of 5-50. ), And Q units (SiO ₂ ). (Here, R is an organic group.) The molar ratios of these are 90-24: 75-0: 50-1, especially 70-28: 70-20: 10-2 (however, 100 in total). It is preferable from a cured | curing material characteristic.

  (E) It is preferable that the polystyrene conversion weight average molecular weights by the gel permeation chromatography (GPC) of a component are 3,000-1,000,000, More preferably, it is 10,000-100,000. Within this range, the polymer is solid or semi-solid and is suitable from the viewpoint of workability and curability.

  The component (E) can be synthesized by combining the compounds used as raw materials for the above units in the polymer so that the required molar ratio is obtained, for example, by hydrolysis in the presence of an acid for condensation. .

Here, as raw materials for RSiO _1.5 units, MeSiCl ₃ , EtSiCl ₃ , PhSiCl ₃ , chlorosilanes such as propyltrichlorosilane, cyclohexyltrichlorosilane, and alkoxysilanes such as methoxysilane corresponding to these chlorosilanes, etc. It can be illustrated. Here, Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group, and Vi represents a vinyl group.

As a raw material for R ² R ³ SiO units of formula (2) are as follows.

（ここで、ｍ＝５〜５０の整数（平均値）、ｎ＝０〜５０の整数（平均値）、かつｍ＋nが５〜５０（平均値）である。）

(Here, an integer (average value) of m = 5 to 50, an integer (average value) of n = 0 to 50, and m + n is 5 to 50 (average value).)

Further, as raw materials for M units, T units, etc., chlorosilanes such as Me ₂ PhSiCl, Me ₂ ViSiCl, MePhSiCl ₂ , MeViSiCl ₂ , Ph ₂ MeSiCl, Ph ₂ ViSiCl, PhViSiCl ₂ , and these chlorosilanes correspond to each. Examples include alkoxysilanes such as methoxysilanes. Here, Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group, and Vi represents a vinyl group.

  These raw materials can be combined in a predetermined molar ratio and obtained, for example, by the following reaction. 100 parts by mass of phenylmethyldichlorosilane, 2100 parts by mass of phenyltrichlorosilane, 2400 parts by mass of chlordimethylsilicone oil having 21 Si atoms, and 3000 parts by mass of toluene are added and mixed, and the mixed silane is dropped into 11000 parts by mass of water. Cohydrolyze at 30-50 ° C. for 1 hour. Thereafter, after aging at 50 ° C. for 1 hour, water is added for washing, followed by azeotropic dehydration, filtration, and vacuum stripping.

In addition, when manufacturing by the said cohydrolysis and condensation, the siloxane unit which has a silanol group may be contained. The (E) component organopolysiloxane usually contains about 0.5 to 10 mol%, preferably about 1 to 5 mol% of such silanol group-containing siloxane units with respect to the total siloxane units. Examples of the silanol group-containing siloxane units include R (HO) SiO units, R (HO) ₂ SiO _0.5 units, and R ₂ (HO) SiO _0.5 units (R is not a hydroxyl group). Since the organopolysiloxane of component (F) contains a silanol group, it reacts with the curable polyorganosiloxane of component (A).

(E) The compounding quantity of a component becomes like this. Preferably it is 2-50 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 3-30 mass parts. If the amount added is small, the effect of improving the continuous formability is small, and low warpage cannot be achieved. When the addition amount is large, the viscosity of the composition increases, which may hinder molding.

(F) Other additives The silicone resin composition of the present invention may further contain various additives as necessary. For example, for the purpose of improving the properties of the resin, mercapto-functional alkoxysilanes such as γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane and other coupling materials, whiskers, silicone powders, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers and other additives, fatty acid esters, glycerate esters, zinc stearate, steers An internal mold release agent such as calcium phosphate, a phenol-based, phosphorus-based, or sulfur-based antioxidant can be added and blended within a range that does not impair the effects of the present invention. However, the composition of the present invention has less discoloration due to light as compared with the conventional thermosetting silicone resin composition, even without containing an antioxidant.

  As a method for producing the composition of the present invention, a silicone resin, a white pigment, an inorganic filler, a curing catalyst, and other additives are blended in a predetermined composition ratio, which is mixed sufficiently uniformly by a mixer or the like, and then heated. Then, a melt mixing process using a kneader, an extruder or the like is performed, followed by cooling and solidification, and pulverization to an appropriate size to obtain a molding material for the epoxy resin composition.

  The obtained silicone resin composition is particularly useful as a sealing material for optical semiconductor devices, particularly for LED cases and photocouplers. FIG. 1 shows a cross-sectional view of an LED reflector that is an example of an optical semiconductor device. In FIG. 1, an optical semiconductor element 1 such as an LED is die-bonded to a lead frame 2 and further bonded to another lead frame (not shown) by a bonding wire 3. A light receiving semiconductor element (not shown) is die-bonded on a lead frame (not shown), and further wire-bonded to another lead frame (not shown) by a bonding wire (not shown). A space between these semiconductor elements is filled with a transparent sealing resin 4. In the example shown in FIG. 1, the cured product of the silicone resin composition of the present invention is used for the white reflector 5. Reference numeral 6 denotes a lens.

  The light reflectivity of the obtained reflector at a wavelength of 450 nm is 70% or more, particularly 80% or more, particularly 85% or more as an initial value, and the reflectance after a 24 hour deterioration test at 180 ° C. is also 70% or more, particularly 80%. % Or more, especially 85% or more can be achieved. When the reflectance is less than 70%, for example, the service life as an LED semiconductor element reflector is shortened.

The most common molding method for the reflector includes a transfer molding method and a compression molding method. The transfer molding method is preferably performed using a transfer molding machine at a molding pressure of 5 to 20 N / mm ² and 120 to 190 ° C. for 30 to 500 seconds, particularly 150 to 185 ° C. for 30 to 180 seconds. In the compression molding method, a compression molding machine is used, and the molding temperature is preferably 120 to 190 ° C. for 30 to 600 seconds, particularly 130 to 160 ° C. for 120 to 300 seconds. Further, in any molding method, post-curing may be performed at 150 to 185 ° C. for 2 to 20 hours.

The epoxy resin composition of the present invention thus obtained is excellent in moldability, heat resistance and light resistance, particularly UV resistance, and therefore suitable for white and blue, and further for premold packages for UV LEDs. Not only is it suitable as a packaging material for solar cells.

  Furthermore, a pre-molded package that collectively seals using this material on a matrix array type metal substrate or organic substrate on which leads and pad portions are formed, leaving only the LED element mounting portion within the scope of the present invention. enter. It can also be used for sealing a normal semiconductor sealing material and various on-vehicle modules.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

The raw materials used in Examples and Comparative Examples are shown below.
[Synthesis Example 1]
(A) Synthesis of organopolysiloxane 100 g of methyltrichlorosilane and 200 g of toluene were placed in a 1 L flask, and a mixed solution of 8 g of water and 60 g of isopropyl alcohol was dropped into the solution under ice cooling. The internal temperature was dropped at −5 to 0 ° C. over 5 to 20 hours, and then heated and stirred at the reflux temperature for 20 minutes. Then, the mixture was cooled to room temperature, and 12 parts by mass of water was added dropwise at 30 ° C. or lower for 30 minutes, followed by stirring for 20 minutes. Further, 25 parts by mass of water was added dropwise, followed by stirring at 40 to 45 ° C. for 60 minutes. Thereafter, 200 parts of water was added to separate the organic layer. The organic layer was washed until neutral, and then subjected to azeotropic dehydration, filtration, and stripping under reduced pressure. A curable organopolysiloxane (A) was obtained.
[Chemical Formula 10]
(CH ₃ ) _1.0 Si (OC ₃ H ₇ ) _0.07 (OH) _0.10 O _1.4 (7)

(B) White pigment White pigment: Titanium dioxide (rutile type), average particle size 0.29 μm (manufactured by Sakai Chemical Industry Co., Ltd.)

(C) Inorganic filler Spherical silica: Average particle size 30 μm (manufactured by Tatsumori)
Spherical silica: average particle size 4μm (manufactured by Tatsumori)
Spherical silica: Average particle size 0.5 μm (manufactured by Admatech)
Crushed silica: average particle size 8μm (Fukushima Ceramics Co., Ltd.)

(D) Curing catalyst Zinc benzoate Wako Pure Chemical Industries, Ltd.

[Synthesis Example 2]
(E) Synthesis of organopolysiloxane 100 g of phenylmethyldichlorosilane, 2100 g of phenyltrichlorosilane, 2400 g of chlorodimethylsilicone oil having both ends of 21 Si, and 3000 g of toluene are mixed, and the above silane mixed in 11000 parts by mass of water is added dropwise. And co-hydrolyzed at 30-50 ° C. for 1 hour. Then, after aging at 50 ° C. for 1 hour, water is added for washing, followed by azeotropic dehydration, filtration, and stripping under reduced pressure, so that the melt viscosity at 150 ° C. is 5 Pa.s, colorless and transparent organopolysiloxane (E) Got.

Additive <br/> Silane coupling agent: KBM803 (manufactured by Shin-Etsu Chemical Co., Ltd.)
Mold release agent; calcium stearate (Wako Pure Chemical Industries, Ltd.)

[Examples 1-3, Comparative Examples 1-3]
In the composition shown in Table 1, (A) an organopolysiloxane, (B) a white pigment, (C) an inorganic filler, (D) a curing catalyst, and (E) an organopolysiloxane are blended and manufactured by roll mixing. Cooling and pulverization gave a white silicone resin composition.

  The following properties were measured for these compositions. The results are shown in Table 1. All moldings were performed at 175 ° C. for 120 seconds using a transfer molding machine.

Spiral flow value was measured under the conditions of 175 ° C., 6.9 N / mm ² , and molding time of 120 seconds using a mold conforming to the EMMI standard.

Using a melt viscosity increasing flow tester, the viscosity was measured at a temperature of 175 ° C. using a nozzle having a diameter of 1 mm under a pressure of 25 kgf.

Bending strength at room temperature Using a mold conforming to the JIS-K6911 standard, a test piece molded under the conditions of 175 ° C., 6.9 N / mm ² and molding time of 120 seconds was bent at room temperature (25 ° C.). The strength was measured.

A disk (cured material) having a diameter of 50 mm and a thickness of 3 mm was molded under the conditions of a light reflectance of 175 ° C., 6.9 N / mm ² and a molding time of 90 seconds, immediately after molding, left at 180 ° C. for 24 hours, and then irradiated with UV ( The light reflectivity at a wavelength of 450 nm after 24 hours of a high-pressure mercury lamp having a peak wavelength of 365 nm (60 mW / cm) was measured using an X-lite 8200 manufactured by SDG Co., Ltd.

Average particle diameter of spherical silica The average particle diameter of the spherical silica was measured using a laser diffraction type particle size distribution analyzer (Cirrus, HR850).

表中、括弧内の数値は各無機充填剤の重量％を示す。

In the table, the numerical values in parentheses indicate the weight percent of each inorganic filler.

  As shown in Table 1, in Comparative Example 1 in which crushed silica was too scrubbed and in Comparative Example 3 in which no crushed silica was contained, the bending strength of the molded product was low. On the other hand, Comparative Example 2 containing a large amount of component (B) was poor in fluidity and could not be molded. In contrast, the examples of the present application had high light reflectivity and high bending strength at room temperature.

The resin composition of the present invention is excellent in strength after curing, can provide a cured product excellent in whiteness, heat resistance and light resistance, and is suitable for optical semiconductor elements, particularly for reflectors.

DESCRIPTION OF SYMBOLS 1 Semiconductor element 2 Lead frame 3 Bonding wire 4 Transparent sealing resin 5 White reflector (hardened | cured material of a silicone resin composition)
6 Lens

Claims (3)

100 parts by mass of an organopolysiloxane represented by the following average composition formula (1) and having a weight average molecular weight (in terms of polystyrene) of 500 to 20000

(CH ₃ ) _a Si (OR ¹ ) _b (OH) _c O _{(4-abc) / 2} (1)

(In the formula, R ¹ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a, b and c are 0.8 ≦ a ≦ 1.5, 0 ≦ b ≦ 0.3, 0.001 ≦ (c ≦ 0.5 and 0.801 ≦ a + b + c <2)
(B) White pigment other than the following (C) 3 to 200 parts by mass (C) Inorganic filler other than the white pigment, 60 to 80% by weight of spherical silica having an average particle size of 0.2 to 40 μm and an average particle size Inorganic filler having an average particle size of 10 to 40 μm, comprising 20 to 40% by weight of 5 to 10 μm of crushed silica
400 to 1000 parts by weight (D) Condensation catalyst 0.01 to 10 parts by weight (E) 2 to 50 parts by weight of an organopolysiloxane having a linear diorganopolysiloxane residue represented by the following formula (2)

(R ² and R ³ are each independently a group selected from an alkyl group having 1 to 3 carbon atoms, a cyclohexyl group, a vinyl group, a phenyl group, and an allyl group, and m is an integer of 5 to 50)   (B) The white pigment is at least one selected from the group consisting of titanium dioxide, magnesium oxide and alumina having an average particle size of 0.05 to 10.0 μm, and 1 to 50 masses relative to the mass of the silicone resin composition. 2. The silicone resin composition according to claim 1, wherein the total mass% of the white pigment and the inorganic filler (C) is 70 to 93 mass% with respect to the amount of the silicone resin composition substance. .   An optical semiconductor device provided with the hardened | cured material of the silicone resin composition of any one of Claims 1-2.

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