JP2012041428A - Silicone resin composition and optical semiconductor case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone resin composition for an optical semiconductor case which gives a cured product which excels in adhesion with a transparency sealing resin, and in which heat resistance and ultraviolet resistance are good.SOLUTION: The silicone resin composition includes: (A) 100 pts.mass of a thermosetting organopolysiloxane; (B) RSiOunit, RSiO unit, and RRSiOunit (wherein Ris a hydroxy group or a monovalent 1-10C hydrocarbon group excluding an alkenyl group, Ris a 2-8C alkenyl group, Ris Ror R, a is 0, 1 or 2, b is 1 or 2, and a+b is 2 or 3); 3-300 pts.mass of an organopolysiloxane including a unit expressed by formula (1) (wherein 0≤m≤100, 0≤n≤100, and 5≤m+n≤100); and (E) 0.01-10 pts.mass of a curing catalyst.

Description

  The present invention relates to a silicone resin composition for forming an optical semiconductor case and an optical semiconductor case comprising a cured product of the composition. In detail, it is related with the silicone resin composition which has favorable adhesiveness with transparent sealing resin, and gives the hardened | cured material excellent in moldability, heat resistance, and light resistance.

  Polyphthalamide resin (PPA) is now widely used as one of the cases of optical semiconductor devices using optical semiconductor elements such as LEDs. However, due to the dramatic progress of today's optical semiconductor technology, the optical semiconductor device has a remarkable increase in output and wavelength, so that an optical semiconductor element encapsulant using a conventional PPA resin as a non-colored and white material in particular. Alternatively, the optical semiconductor case material is remarkably deteriorated by long-term use, and color unevenness, peeling, mechanical strength reduction, etc. are likely to occur. Therefore, it is desired to effectively solve such a problem.

  Patent Document 1 describes an epoxy resin composition for sealing a B-stage optical semiconductor containing an epoxy resin, a curing agent, and a curing accelerator as constituent components. The epoxy resin composition for sealing a B-stage optical semiconductor has a problem that it yellows when left for a long time at a high temperature. As an epoxy resin composition for sealing a light emitting device having excellent heat resistance and light resistance, one containing an isocyanuric acid derivative epoxy resin is known (Patent Document 2), but it is not sufficient in terms of light resistance.

  Patent Document 5 discloses a thermosetting resin composition containing an epoxy resin, a curing agent, a curing catalyst, an inorganic filler, a white pigment, and a coupling agent, and has a light reflectance of 80% or more at a wavelength of 800 nm to 350 nm. Although a thermosetting resin composition for light reflection providing a cured product is described, when the composition is left for a long time at a high temperature, the LED is UV-LED, white LED, blue LED, etc. In the case of a high luminance type, a problem of yellowing occurs.

  Further, the heat released from the LED deteriorates the transparent sealing resin and the reflector, and causes a decrease in light luminance of the optical semiconductor device. Therefore, development of a material having high reflectivity and heat resistance is awaited. Addition-curing and condensation-curing silicone resin compositions are known as resin compositions for sealing light-emitting elements that have high transparency, long-term durability, high-temperature stability, and excellent light resistance (Patent Documents 3 and 4). . As LED reflector materials, thermosetting transfer molding materials in which various fillers are blended based on a silicone resin have been developed (Patent Documents 6 to 9). The reflector material has excellent heat resistance, cold resistance, and weather resistance, and excellent mold releasability. Further, Patent Document 10 describes a silicone resin composition for an LED case that reduces the warpage of a semiconductor device due to curing and gives a cured product excellent in whiteness, heat resistance, and weather resistance.

Japanese Patent Laid-Open No. 02-189958 JP 2005-306952 A JP 2008-280534 A JP 2009-275214 A JP 2006-140207 A JP 2009-155415 A JP 2009-221393 A JP 2010-018786 A JP 2010-021533 A JP 2010-106243 A

  However, the cured product of the silicone resin composition has a problem that the adhesiveness with the transparent sealing resin is insufficient. For optical semiconductor cases for LEDs, etc., LED chips are mounted on lead frames and wire bonded, and then the top is sealed with epoxy resin or silicone resin, and the reflector material prevents light from the LEDs from leaking. It is common to seal with (reflecting material), and the adhesiveness between the resin composition to be sealed and the reflector material is required. Conventional reflector materials have poor adhesion to the sealing resin, and in the solder reflow process exposed to high temperatures (215 to 260 ° C.), there is a problem that peeling occurs at the interface between the reflector material and the resin, and reliability cannot be guaranteed. ing.

  Accordingly, the present invention provides a silicone resin composition for forming an optical semiconductor case that provides a cured product excellent in adhesiveness with a transparent sealing resin and having good heat resistance and ultraviolet resistance, and light comprising the cured product of the composition. An object is to provide a semiconductor case.

  As a result of intensive studies to solve the above problems, the present inventors have found that a silicone resin composition comprising a thermosetting organopolysiloxane and an organopolysiloxane having a linear diorganopolysiloxane unit having a predetermined length is moldable. The present invention has been found to be excellent in heat resistance and ultraviolet resistance, and further to provide a case having excellent adhesion to a transparent sealing resin by incorporating an alkenyl group into the cured product of the silicone resin composition. It came to.

（式（１）中、Ｒ^２、Ｒ^３及びＲ^４は上述の通りであり、ｍは０≦ｍ≦１００の整数、ｎは０≦ｎ≦１００の整数、但し、５≦ｍ＋ｎ≦１００である）
（Ｅ）硬化触媒 ０．０１〜１０質量部
を含有するシリコーン樹脂組成物及び、該シリコーン樹脂組成物の硬化物よりなる光半導体ケースを提供する。 That is, the present invention
(A) Thermosetting organopolysiloxane 100 parts by mass (B) R ² SiO _3/2 units, R ² ₂ SiO units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where , R ² are each independently a hydroxyl group or a monovalent hydrocarbon group having 1 to 10 carbon atoms excluding an alkenyl group, R ⁴ is independently an alkenyl group having 2 to 8 carbon atoms, and R ³ is independently And R is a group represented by R ² or R ⁴ , a is 0, 1 or 2, b is 1 or 2, and a + b is 2 or 3.
^{3 to} 300 parts by mass of an organopolysiloxane in which at least a part of the R ² ₂ SiO unit and / or the R ³ R ⁴ SiO unit is repeated to form a unit represented by the following formula (1)

(In the formula (1), R ² , R ³ and R ⁴ are as described above, m is an integer of 0 ≦ m ≦ 100, n is an integer of 0 ≦ n ≦ 100, provided that 5 ≦ m + n ≦ 100. is there)
(E) Curing catalyst Provided is an optical semiconductor case comprising a silicone resin composition containing 0.01 to 10 parts by mass and a cured product of the silicone resin composition.

The composition of the present invention is a silicone resin composition comprising a thermosetting organopolysiloxane and an organopolysiloxane having a linear diorganopolysiloxane unit of a predetermined length, wherein the latter organopolysiloxane is an alkenyl. It is characterized by containing a group. The cured product obtained by curing the silicone resin composition has good adhesion to the transparent sealing resin and excellent heat resistance and UV resistance, and is reliable by suppressing discoloration, especially yellowing due to heat. An optical semiconductor case excellent in performance can be provided.

It is the schematic which shows an example of the optical semiconductor case (LED reflector) using the silicone resin composition of this invention.

(A) The thermosetting organopolysiloxane (A) component is a thermosetting organopolysiloxane that can be cured by heating to form a crosslinked structure. Such a thermosetting organopolysiloxane is not particularly limited, and is an organopolysiloxane having one or more hydroxyl groups bonded to silicon atoms in one molecule represented by the following average composition formula (2). Is preferred.
[Chemical 2]
(CH ₃ ) _a Si (OR ¹ ) _b (OH) _c O _{(4-abc) / 2} (2)

In the above formula (2), R ¹ independently of each other is a 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, or an n-butyl group, or a vinyl group. And an alkenyl group such as an allyl group, and a methyl group and an isopropyl group are preferable in that the raw material is easily available.

In the above formula (2), a is a number 0.8 ≦ a ≦ 1.5, preferably 0.9 ≦ a ≦ 1.2, more preferably 0.9 ≦ a ≦ 1.1, and b Is a number 0 ≦ b ≦ 0.3, preferably 0.001 ≦ b ≦ 0.2, more preferably 0.01 ≦ b ≦ 0.1, and c is 0.001 ≦ c ≦ 0.5, The number is preferably 0.01 ≦ c ≦ 0.3, more preferably 0.05 ≦ c ≦ 0.2, provided that 0.801 ≦ a + b + c <2, preferably 0.911 ≦ a + b + c ≦ 1.8. More preferably, the number satisfies 1.0 ≦ a + b + c ≦ 1.5. If a is less than the above lower limit value, the cured product is too hard and may cause cracks and the like. If b exceeds the upper limit, crack prevention performance may not be sufficient. The content of OR ¹ can be quantified by an infrared absorption spectrum (IR), an alcohol quantification method by alkali cracking, or the like. If c exceeds the above upper limit value, the hardness of the cured product is too high, which is not preferable because the cured product has poor crack resistance. If c is less than the above lower limit, the melting point tends to be high, which may cause problems in workability. 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 86%, the melting point becomes low, and if it exceeds 96%, the melting point tends to be too high.

  The thermosetting organopolysiloxane has a polystyrene-reduced weight average molecular weight measured by GPC of 500 to 20000, preferably 1000 to 10000, more preferably 2000 to 8000. If the molecular weight is less than the lower limit, solidification is difficult, and if the molecular weight exceeds the upper limit, the viscosity increases and the fluidity may decrease.

The thermosetting organopolysiloxane can be expressed by a combination of Q units (SiO _4/2 ), T units (CH ₃ SiO _3/2 ), and D units (CH ₃ SiO _2/2 ). The ratio of the number of moles of the T unit to the total number of moles of siloxane units is 70 mol% or more, desirably 75 mol% or more, and particularly preferably 80 mol% or more. If the T unit is less than 70 mol%, the overall balance of hardness, adhesion, and appearance may be lost. The balance is D units and Q units, which are preferably 30 mol% or less based on the total number of moles of all siloxane units. Too many D units and Q units is not preferable because the melting point of the organopolysiloxane increases.

The thermosetting organopolysiloxane can be obtained, for example, as a hydrolytic condensate of organosilane represented by the following general formula.
[Chemical 3]

(CH ₃ ) _n SiX _4-n

In the formula, X is a halogen atom such as chlorine or a group represented by the above OR ¹ , and n is 1, 2 or 0. Among these, in order to obtain a solid organopolysiloxane, X is preferably a halogen atom, particularly a chlorine atom.

  Examples of the organosilane include methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, tetrachlorosilane, tetramethoxylane, and tetraethoxylane.

  The organosilane may be hydrolyzed and condensed by a usual method. For example, 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 is present. It is preferable to carry out below. For example, when a silane containing a chloro group as a hydrolyzable group is used, a desired hydrolysis condensate having an appropriate molecular weight can be obtained using hydrochloric acid generated by addition of water as a catalyst.

  The amount of water added at the time of hydrolysis and condensation is usually 0.9 to 1.6 mol per 1 mol of the total amount of hydrolyzable groups (for example, chloro group) in the organosilane. , Preferably 1.0 to 1.3 mol. By setting the amount of water within the above range, a cured product having excellent workability and toughness can be provided.

  The organosilane is usually preferably used after being hydrolyzed in an organic solvent such as alcohols, ketones, esters, cellosolves, and aromatic compounds. Specifically, for example, alcohols such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, n-butanol, and 2-butanol, and toluene and xylene are preferable as aromatic compounds, and the curability of the composition and the toughness of the cured product are excellent. Since it becomes excellent, the combined use of isopropyl alcohol and toluene is more preferable. The reaction temperature for hydrolysis and condensation is preferably 10 to 120 ° C, more preferably 20 to 100 ° C. When the reaction temperature satisfies this range, a solid hydrolysis condensate that can be used in the next step is obtained without gelation.

For example, an example using methyltrichlorosilane as a raw material is shown below. Water and isopropyl alcohol are added to methyltrichlorosilane dissolved in toluene to cause partial hydrolysis (reaction temperature of -5 ° C to 100 ° C), and then water is added in such an amount that the total amount of the remaining chloro groups is hydrolyzed. By reacting, an organopolysiloxane represented by the following average composition formula is obtained.
[Chemical 4]

(CH ₃ ) _a Si (OC ₃ H ₇ ) _b (OH) _c O _{(4-abc) / 2}

(Wherein a, b and c are as described above.)

Specific examples of the thermosetting organopolysiloxane represented by the above average composition formula include compounds represented by the following formula.
[Chemical 5]
(CH ₃ ) _1.0 Si (OC ₃ H ₇ ) _0.07 (OH) _0.13 O _1.4

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

（ｍは０≦ｍ≦１００の整数、ｎは０≦ｎ≦１００の整数、但し５≦ｍ＋ｎ≦１００） (B) The organopolysiloxane (B) component is composed of R ² SiO _3/2 units, R ² ₂ SiO units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where R ² Are each independently a hydroxyl group or a monovalent hydrocarbon group having 1 to 10 carbon atoms excluding an alkenyl group, R ⁴ is independently an alkenyl group having 2 to 8 carbon atoms, and R ³ is independently R ² Or a group represented by R ⁴ , a is 0, 1 or 2, b is 1 or 2, and a + b is 2 or 3, of which R ² ₂ SiO units and / or It is an organopolysiloxane in which at least a part of the R ³ R ⁴ SiO unit repeats to form a unit represented by the following formula (1).

(M is an integer of 0 ≦ m ≦ 100, n is an integer of 0 ≦ n ≦ 100, where 5 ≦ m + n ≦ 100)

  This invention improves the outstanding adhesiveness with respect to transparent sealing resin by taking in an alkenyl-group containing organopolysiloxane in the hardened | cured material of a silicone resin composition. In particular, when the addition-curable silicone resin composition is used as a sealing resin, particularly excellent adhesiveness is exhibited by a reaction between a hydrosilyl group in the sealing resin and an alkenyl group in the cured product. Further, (B) the organopolysiloxane has a linear diorganopolysiloxane unit of a predetermined length, so that a cured product having heat resistance and light resistance can be obtained without distorting the apparatus during curing. be able to.

R ² is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms excluding an alkenyl group, and such R ² is preferably an alkyl group having 1 to 6 carbon atoms or a cyclohexane having 4 to 10 carbon atoms. Examples thereof include an alkyl group and an aryl group having 6 to 10 carbon atoms, and more preferable examples include an alkyl group having 1 to 3 carbon atoms, a cycloalkyl group having 4 to 6 carbon atoms, and an aryl group having 6 to 8 carbon atoms. . Of these, a methyl group or a phenyl group is preferable. R ⁴ is an alkenyl group having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms. m is an integer of 0 ≦ m ≦ 100, n is an integer of 0 ≦ n ≦ 100, provided that m + n is an integer of 5 to 100, preferably 8 to 50, more preferably 10 to 40. When m + n is less than the lower limit, flexibility (crack resistance) of the cured product is poor, and when it exceeds the upper limit, the viscosity increases, so the component (B) tends not to melt in the composition.

In addition to the linear organopolysiloxane unit represented by the above formula (1), the component (B) is a D unit (R ₂ SiO) other than the linear organopolysiloxane unit, an M unit (R ₃ SiO _{1 / 2} ), T units (RSiO _3/2 ) (wherein R independently represents R ² or R ⁴ ). These molar ratios are 90 to 24:75 to 9:50 to 1, particularly 70 to 28:70 to 20:10 to 2 (provided that the total is 100). It is preferable in terms of characteristics. The component (B) may further contain a Q unit (SiO ₂ ). The total number of moles of the linear organopolysiloxane unit and the other D units (R ₂ SiO ₁ ) is preferably 30 mol% or more, more preferably 50 to 100 mol%, particularly 80 to 100 mol% is preferably the above-mentioned linear organopolysiloxane unit.

The component (B) contains 0.5 to 5 mol% of alkenyl groups with respect to the total number of moles of organic groups bonded to silicon atoms (meaning the above R ² , R ³ and R ⁴ ). Preferably it is 1-3 mol%. If it exceeds the upper limit, the mechanical strength or heat resistance of the cured product of the silicone resin composition of the present invention is lowered, and if it is less than the lower limit, the adhesiveness to the transparent sealing resin is inferior.

  The component (B) can be synthesized by combining the compounds used as raw materials for the above units in a required molar ratio, for example, hydrolysis and condensation in the presence of an acid.

Examples of the raw material for the linear organopolysiloxane unit represented by the above formula (1) include the following.

（式中、ｍ＝０〜１００の整数、ｎ＝０〜１００の整数であり、但しｍ＋ｎは５〜１００である。）

(In the formula, m is an integer of 0 to 100, and n is an integer of 0 to 100, where m + n is 5 to 100.)

The raw material for the T unit (RSiO _3/2 unit) is MeSiCl ₃ , EtSiCl ₃ , PhSiCl ₃ , chlorosilanes such as propyltrichlorosilane and cyclohexyltrichlorosilane, and alkoxysilanes such as methoxysilane corresponding to these chlorosilanes. Examples can be given. Here, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

The raw materials for the D unit (R ₂ SiO) and M unit (R ₃ SiO _1/2 ) include Me ₂ PhSiCl, Me ₂ ViSiCl, MePhSiCl ₂ , MeViSiCl ₂ , Ph ₂ MeSiCl, Ph ₂ ViSiCl, PhViSiCl _{2 and the} like. Chlorosilanes, and alkoxysilanes such as methoxysilanes corresponding to each of these chlorosilanes. Here, Me represents a methyl group, Et represents an ethyl group, Ph represents a phenyl group, and Vi represents a vinyl group.

  (B) The organopolysiloxane can be obtained by combining the raw material compounds described above at a predetermined molar ratio, for example, by the following reaction. Methyl vinyl dichlorosilane, trichlorophenyl silane, dichloro linear dimethylpolysiloxane at both ends and toluene are mixed, the mixed silane is dropped into water and co-hydrolyzed at 30 to 50 ° C. for 1 hour. Then, after aging at 50 ° C. for 1 hour, water is added for washing, azeotropic dehydration, filtration, and stripping under reduced pressure.

  The weight average molecular weight of the organopolysiloxane in terms of polystyrene by GPC is 3,000 to 1,000,000, preferably 5,000 to 90,000. Within the above range, the organopolysiloxane is preferably in a solid or semi-solid state and excellent in workability and curability.

The component (B) may have a hydrogen atom (silanol group) bonded to a silicon atom in the molecule. Since the component (B) has a silanol group, it undergoes a condensation reaction with the thermosetting organopolysiloxane (A), so the hardness of the resulting cured product is increased and the cured product is excellent in solvent resistance. In the organopolysiloxane of the present invention, the ratio of the number of moles of silanol group-containing siloxane units to the total number of moles of all siloxane units is 0.01 to 10 mol%, preferably 0.05 to 5 mol%. Is preferred. Examples of the silanol group-containing siloxane units include R (HO) SiO units, R (HO) ₂ SiO _1/2 units, and R ₂ (HO) SiO _1/2 units (wherein R is not a hydroxyl group) ² , R ³ , R ⁴ ).

(B) The compounding quantity of a component is 3-300 mass parts with respect to 100 mass parts of (A) component, Preferably it is 5-200 mass parts. If it is less than the lower limit, sufficient adhesion to the transparent sealing resin cannot be obtained. If the value exceeds the upper limit, a curing failure may occur and the molding may be hindered.

(C) Pigment The (C) pigment is added to color the cured product, improve the strength, and reduce the linear expansion coefficient. When the silicone resin composition of the present invention is used as a reflector application, a white pigment (white colorant) is preferable for the purpose of reflection. As the white pigment, 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, barium sulfate and alumina are preferable, and titanium dioxide is particularly 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 pigment has an average particle size of 0.05 to 10.0 μm, preferably 0.05 to 4.0 μm, and more preferably 0.05 to 2.0 μm. In addition, in order to improve the mixing and dispersibility with the (A) component, the (B) component, and the (D) inorganic filler, the white pigment is pretreated with a hydroxide such as Al or Si or an organic compound in advance. May be. 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 pigment is 3 to 400 parts by mass, preferably 5 to 200 parts by mass, and particularly 10 to 150 parts by mass with respect to 100 parts by mass of the component (A). If it is less than the said lower limit, sufficient whiteness may not be obtained. In particular, it is difficult to obtain a cured product having a reflectance of 70% or more as an initial value and a reflectance after heating at 180 ° C. for 24 hours of 70% or more. Further, if the value exceeds the upper limit, the mechanical strength is inferior, which is not preferable. The amount of the pigment is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and most preferably 10 to 30% by mass with respect to the entire silicone resin composition.

(D) Inorganic filler (D) Inorganic filler is a filler other than the above-mentioned (C) pigment. As this filler, what is normally mix | blended with a silicone resin composition can be used. Examples thereof include silicas such as fused silica, fused spherical silica and crystalline silica, silicon nitride, aluminum nitride, boron nitride, antimony trioxide and the like. The average particle size and shape of these inorganic fillers are not particularly limited, but the average particle size is 5 to 40 μm, preferably 7 to 35 μm. 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.

  Among them, fused silica and fused spherical silica are preferable, and in order to obtain a high fluidity of the resin composition, a combination of fine regions of 3 μm or less, 4 to 8 μm medium particle size region, and 10 to 40 μm coarse region are combined. It is desirable to use it. In particular, when a pre-mold package having a narrow portion is molded or used as an underfill material, it is preferable to use an inorganic filler having an average particle size of 1/2 with respect to the thickness of the narrow portion.

  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.

  The blending amount of the inorganic filler is preferably 400 to 1500 parts by mass, particularly 600 to 1000 parts by mass with respect to 100 parts by mass of the component (A). If it is less than the above lower limit value, the target linear expansion coefficient may not be obtained, and if it exceeds the above upper limit value, unfilled mold failure or flexibility due to thickening will be lost, resulting in defects such as peeling in the element. There is a case. In particular, it is desirable that the total amount of the inorganic filler and the above-described (C) pigment is 70 to 93% by mass, particularly 75 to 91% by mass of the entire silicone resin composition.

(E) Curing catalyst The (E) curing catalyst is blended to accelerate the curing reaction of the component (A) or the curing reaction of the components (A) and (B). The curing catalyst may be any one that is normally used as a curing catalyst for thermosetting silicone resins, and may be appropriately selected in consideration of the storage stability of the silicone composition, the desired hardness, and the like. 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.

  Examples of the curing catalyst include trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, n-hexylamine, tributylamine, diazabicycloundecene (DBU), dicyandiamide and the like; tetraisopropyl titanate, tetrabutyl titanate , Titanium acetylacetonate, aluminum triisobutoxide, aluminum triisopropoxide, zirconium tetra (acetylacetonate), zirconium tetrabutyrate, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin Octylate, dibutyltin laurate, zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate, lauric acid sub- Metal-containing compounds such as zinc stearate, aluminum phosphate, aluminum triisopropoxide, aluminum trisacetylacetonate, aluminum bisethylacetoacetate / monoacetylacetonate, diisopropoxybis (ethylacetoacetate) titanium, di And organic titanium chelate compounds such as isopropoxybis (ethylacetoacetate) titanium. Among them, organometallic catalysts such as zinc octylate, zinc benzoate, zinc p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminum phosphate, aluminum triisopropoxide are preferable, and in particular, zinc benzoate, Organic titanium chelate compounds are preferred.

Other Additives The silicone resin composition of the present invention can further contain various additives as necessary in addition to the above components. 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, epoxy resins, whiskers, silicone powders, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers and other additives, fatty acid esters, glycerate esters, stearic acid An internal mold release agent such as zinc / calcium stearate, a phenol-based, phosphorus-based, or sulfur-based antioxidant can be added and blended within a range not impairing 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.

  The silicone resin composition of the present invention is prepared by blending the components (A) to (E) and other additives as required at a predetermined composition ratio and mixing them sufficiently uniformly with a mixer or the like, It can be prepared by performing a melt mixing process using a kneader, an extruder or the like, then cooling and solidifying, and pulverizing to an appropriate size.

  The cured product of the silicone resin composition of the present invention can be effectively used as a case for a semiconductor / electronic device, particularly an LED. FIG. 1 shows an example of an optical semiconductor case (LED reflector) using the silicone resin composition of the present invention. In the optical semiconductor case, the contact surface with the transparent resin encapsulating the optical semiconductor becomes a reflective surface (reflector), and light such as an LED sealed with a transparent resin, for example, a silicone resin, an epoxy resin, or the like inside. A semiconductor element is held and accommodated. In FIG. 1, the cured product of the silicone resin composition of the present invention is a reflector 5.

  The cured product obtained by curing the silicone resin composition of the present invention has a light reflectance at a wavelength of 450 nm of 70% or more, particularly 80% or more, particularly 85% or more at an initial value, and at 180 ° C. for 24 hours. The light reflectance after the deterioration test can be achieved at 70% or more, particularly 80% or more, especially 85% or more. Since the light reflectance of hardened | cured material is 70% or more, the lifetime as a reflector becomes long.

As a method for forming the optical semiconductor case, a transfer molding method or a compression molding method can be used. In the transfer molding method, it is preferable to mold 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, post-curing may be performed at 150 to 185 ° C. for 2 to 20 hours.

A cured product obtained by curing the silicone resin composition of the present invention is excellent in adhesiveness with a transparent sealing resin such as a silicone resin. Further, the cured product of the silicone resin composition of the present invention is excellent in heat resistance, light resistance, and ultraviolet resistance, and provides an optical semiconductor case excellent in reliability by suppressing discoloration due to heat, particularly yellowing. be able to. Furthermore, the silicone resin composition of the present invention can be suitably used as a sealing material for photocouplers. Moreover, the silicone resin composition of the present invention is not only suitable for white and blue, and also for ultraviolet LED packages, but is also optimal as a package material for solar cells.

In addition, the silicone resin composition of the present invention is a pre-mold package that encapsulates a resin on a matrix array type metal substrate or organic substrate on which lead portions and pad portions are formed, with only the LED element mounting portion being open. It can also be used as a sealing material. The silicone resin composition of the present invention can also be used for sealing semiconductor sealing materials 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.

[Synthesis Example 1]
(A) Synthesis of thermosetting organopolysiloxane 100 parts by mass of methyltrichlorosilane and 200 parts by mass of toluene were placed in a 1 L flask, and a mixed solution of 8 parts by mass of water and 60 parts by mass of isopropyl alcohol was dropped into the liquid under ice cooling. did. 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 less over 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 vacuum stripping, whereby a colorless and transparent solid represented by the following formula (3) (melting point: 76 ° C.) 36.0 parts by mass of heat A curable organopolysiloxane (A) was obtained (polystyrene equivalent weight average molecular weight measured by GPC is 3000).
[Chemical Formula 10]
(CH ₃ ) _1.0 Si (OC ₃ H ₇ ) _0.07 (OH) _0.10 O _1.4 (3)

[Synthesis Example 2]
(B) Synthesis of organopolysiloxane 129 parts by mass of dimethyldichlorosilane and 1483 parts by mass of octamethylcyclic siloxane were mixed, and 26 parts by mass of fuming nitric acid was added dropwise, followed by stirring at 30 to 35 ° C for 2 hours. The mixture was stirred at 45 to 55 ° C. for 16 hours and cooled to obtain 1548 parts by mass of both-ends dichloro linear polydimethylsiloxane represented by the following formula (4).
[Chemical 11]
ClMe ₂ SiO (Me ₂ SiO) ₁₉ SiMe ₂ Cl (4)

(Chlorine content is 0.13 mol / 100 g, kinematic viscosity at 25 ° C. is 25 cs)

Next, 350 parts by weight of water was put into a 5 L flask, and 34.7 parts by mass of both ends dichloro linear polydimethylsiloxane represented by the above formula (4), 58.9 parts by mass of trichlorophenylsilane, methylvinyldichlorosilane 6 A mixture of 4 parts by weight and 65.7 parts by weight of toluene was added dropwise. The liquid temperature in the flask was dropped from 25 ° C. to 40 ° C. over 3 to 5 hours, and the resulting reaction solution was stirred at 25 ° C. to 40 ° C. for 60 minutes. An organic layer was collected from the mixed solution and washed until the organic layer became neutral, followed by azeotropic dehydration to adjust the nonvolatile content to 50%. To this was added 0.3 part by weight of 28% aqueous ammonia, and the mixture was stirred at 25 ° C. to 40 ° C. for 30 minutes, followed by azeotropic dehydration. Thereafter, 0.06 part by weight of glacial acetic acid was added to make the solution acidic, and azeotropic dehydration was performed again. The obtained solution was filtered and subjected to a reduced pressure strip to obtain 67.5 parts by mass of a colorless and transparent solid represented by the following formula (5) (vinyl group relative to the total number of moles of organic groups bonded to silicon atoms). The melt viscosity at 150 ° C. measured using a BL-type rotational viscometer (rotor No. 3) was 3,500 mPa · s, and the polystyrene equivalent weight average molecular weight measured by GPC was 30 mol%. , 000).

(C) Pigment White pigment: Titanium dioxide (rutile type), average particle size 0.29 [mu] m, R-45M (manufactured by Sakai Chemical Industry Co., Ltd.)

(D) Inorganic filler Fused spherical silica: Average particle size 25 μm, MSR-2500 (manufactured by Tatsumori)

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

(F) Additives Silane coupling agent: KBM803 (manufactured by Shin-Etsu Chemical Co., Ltd.)
Mold release agent: Calcium stearate (Wako Pure Chemical Industries, Ltd.)

[Examples 1-6, Comparative Examples 1-4]
Each component was mixed by roll mixing with the composition and formulation shown in Table 1, cooled and pulverized to prepare a white silicone resin composition.

[Synthesis Example 3]
Synthesis of organopolysiloxane for comparative test 100 parts by weight of phenylmethyldichlorosilane, 2100 parts by weight of phenyltrichlorosilane, 2400 parts by weight of chlorodimethylsilicone oil having 21 Si atoms, 3000 parts by weight of toluene, and 11,000 parts by weight of water The silane mixed therein is dropped and cohydrolyzed at 30 to 50 ° C. for 1 hour. Then, after aging at 50 ° C. for 1 hour, water was added for washing, followed by azeotropic dehydration, filtration, and vacuum stripping to obtain a colorless and transparent organopolysiloxane having a melt viscosity of 5 Pa.s at 150 ° C. .

[Comparative Examples 5 and 6]
Using the organopolysiloxane for comparative test (linear organopolysiloxane containing no alkenyl group) obtained in Synthesis Example 3 in place of the component (B), each component was blended with the composition shown in Table 1, and a roll A white silicone resin composition was obtained by mixing, cooling and grinding.

  These compositions were used in the following tests. The results are shown in Table 1.

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.

Adhesion test On the cured product obtained by curing the resin compositions of Examples and Comparative Examples at 175 [deg.] C. for 120 seconds, the transparent sealing resin I or II was 17.5 mm < ² > and the thickness was 0. A 5 mm ² Si chip was placed thereon and cured under conditions of 150 ° C. for 4 hours to prepare five test pieces. The adhesive strength of each test piece was measured by a shear bond strength test using a 4000 bond tester manufactured by Dage, and an average value of five test pieces was obtained.

Transparent sealing resin I: methyl silicone (addition-curable resin composition containing vinyl group-containing dimethylsiloxane and methylhydrogensiloxane in an amount such that SiH group / SiVi group = 1.1)
Transparent encapsulating resin II: phenyl silicone (addition-curable resin composition containing vinyl group-containing dimethyldiphenylsiloxane and methylhydrogensiloxane in an amount of SiH group / SiVi group = 1.1)

A disk (cured product) having a diameter of 50 mm × thickness of 3 mm was molded under conditions of a light reflectance of 175 ° C., a molding pressure of 6.9 N / mm ² , and a molding time of 120 seconds, and immediately after molding, left at 180 ° C. for 24 hours, and The light reflectance at a wavelength of 350 to 400 nm after 24 hours with UV irradiation (a high pressure mercury lamp with a peak wavelength of 365 nm of 60 mW / cm) was measured using an X-lite 8200 manufactured by SDG Co., Ltd., and the initial reflectance was measured. Table 1 shows the reflectance after the heat resistance test and the reflectance after the weather resistance test.

In Table 1, the cured products of Comparative Examples 1 and 3 that do not contain an alkenyl group-containing organopolysiloxane and Comparative Example 2 in which the blending amount of the alkenyl group-containing organopolysiloxane is too small have low adhesion to the transparent sealing resin. The silicone resin composition of Comparative Example 4 containing no thermosetting organopolysiloxane is not cured and cannot be molded. The cured products of the resin compositions of Comparative Examples 5 and 6 composed of thermosetting organopolysiloxane and organopolysiloxane containing no alkenyl group have low adhesion to the transparent sealing resin. On the other hand, the hardened | cured material which consists of a silicone resin composition of this invention has strong adhesiveness with respect to transparent sealing resin, and is excellent in heat resistance and ultraviolet-ray resistance.

The cured product obtained by curing the silicone resin composition of the present invention is excellent in adhesiveness with the transparent sealing resin. Moreover, since the cured product of the silicone resin composition of the present invention is excellent in heat resistance, light resistance, and ultraviolet resistance, it provides an optical semiconductor case with excellent reliability by suppressing discoloration due to heat, particularly yellowing. can do. Therefore, it is not only suitable for white, blue, and even ultraviolet LED packages, but is also optimal as a package material for solar cells.

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

Claims (11)

(A) Thermosetting organopolysiloxane 100 parts by mass (B) R ² SiO _3/2 units, R ² ₂ SiO units, and R ³ _a R ⁴ _b SiO _{(4-ab) / 2} units (where , R ² are each independently a hydroxyl group or a monovalent hydrocarbon group having 1 to 10 carbon atoms excluding an alkenyl group, R ⁴ is independently an alkenyl group having 2 to 8 carbon atoms, and R ³ is independently And R is a group represented by R ² or R ⁴ , a is 0, 1 or 2, b is 1 or 2, and a + b is 2 or 3.
^{3 to} 300 parts by mass of an organopolysiloxane in which at least a part of the R ² ₂ SiO unit and / or the R ³ R ⁴ SiO unit is repeated to form a unit represented by the following formula (1)

(In the formula (1), R ² , R ³ and R ⁴ are as described above, m is an integer of 0 ≦ m ≦ 100, n is an integer of 0 ≦ n ≦ 100, provided that 5 ≦ m + n ≦ 100. is there)
(E) Curing catalyst A silicone resin composition containing 0.01 to 10 parts by mass. (A) A component is represented by the following average composition formula (2), The silicone resin composition of Claim 1 characterized by the above-mentioned.
[Chemical 2]
(CH ₃ ) _a Si (OR ¹ ) _b (OH) _c O _{(4-abc) / 2} (2)

(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)   The silicone resin composition according to claim 1 or 2, wherein in component (B), the total number of moles of alkenyl groups relative to the total number of moles of organic groups bonded to silicon atoms is 0.5 to 5.0 mol%. object.   Furthermore, the silicone resin composition of any one of Claims 1-3 which contains (C) pigment in 3-400 mass parts with respect to 100 mass parts of (A) component.   The silicone resin composition according to claim 4, wherein the component (C) has an average particle size of 0.05 to 10.0 μm.   6. The silicone resin composition according to claim 4, wherein the component (C) is at least one selected from the group consisting of titanium dioxide, magnesium oxide, barium sulfate and alumina.   Furthermore, the silicone resin composition of any one of Claims 1-6 which contains (D) inorganic filler by 400-1500 mass parts with respect to 100 mass parts of (A) component.   The silicone resin composition according to claim 7, wherein the component (D) has an average particle size of 5 to 40 μm.   The silicone resin composition according to claim 7 or 8, wherein the component (D) is at least one selected from fused silica and fused spherical silica.   (E) The silicone resin composition of any one of Claims 1-9 whose component is an organometallic catalyst.   The optical semiconductor case which consists of hardened | cured material of the silicone resin composition of any one of Claims 1-10.

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