JP6873654B2 - A semiconductor light emitting device including a curable polysiloxane composition, a sealing material for a semiconductor light emitting device containing the curable polysiloxane composition, and a cured product of the sealing material. - Google Patents

Description

The present invention relates to a novel curable polysiloxane composition, a sealing material for a semiconductor light emitting device using the same, and a semiconductor light emitting device provided with a cured product of the sealing material. More specifically, the present invention relates to a dehydrogenation condensation type curable polysiloxane composition having excellent heat resistance, light resistance, water heat resistance, UV resistance, particularly crack resistance, and low foaming property.

In semiconductor light emitting devices, particularly light emitting diodes (hereinafter, appropriately abbreviated as "LED") and semiconductor light emitting devices such as semiconductor lasers, the semiconductor light emitting element is a member such as a transparent resin (member for semiconductor light emitting device). It is generally sealed with a diode.
For example, an epoxy resin is used as the member for the semiconductor light emitting device. Further, there are known ones that convert the emission wavelength from a semiconductor light emitting element by containing a pigment such as a phosphor in the epoxy resin or the like.

However, since epoxy resin has high hygroscopicity, there is a problem that cracks occur due to heat from the semiconductor light emitting element generated when the semiconductor light emitting device is used for a long time, and the phosphor and the light emitting element deteriorate due to the infiltration of moisture. was there.
Further, in recent years, since the epoxy resin deteriorates and is colored as the emission wavelength of the LED is shortened, there is also a problem that the brightness of the semiconductor light emitting device is remarkably lowered in long-time lighting and use at high output. ..

In response to these problems, silicone resins having excellent heat resistance and ultraviolet light resistance have come to be used as alternatives to epoxy resins. That is, as a material having excellent heat resistance and ultraviolet light resistance, a semiconductor light emitting device using a silicone resin (polysiloxane composition) has been proposed. The silicone resin can be classified according to the curing mechanism, and examples thereof include polyorganosiloxanes such as addition polymerization curing type, polycondensation curing type, ultraviolet curing type, and peroxide sulfide type, and members for semiconductor light emitting devices, particularly LED elements. For sealing, an addition curing type in which an alkenyl group-containing polyorganosiloxane and a polyorganohydrogensiloxane are cured by a hydrosilylation reaction in the presence of a platinum-based catalyst, and a condensation between the silanol groups of the silanol group-containing polyorganosiloxane. A dehydration condensation curing type that cures by reaction is well known.

On the other hand, a dehydrogenation condensation type polyorganosiloxane in which a silanol group-containing polyorganosiloxane and a polyorganohydrogensiloxane are cured with a catalyst that promotes a dehydrogenation reaction is a polyorganosiloxane foaming material, for example, Patent Document 1. It is disclosed in. The dehydrogenation condensation type polyorganosiloxane is excellent in heat resistance and light resistance because an alkylene chain is not introduced at the time of cross-linking, and is also excellent in adhesiveness due to the residual silanol group. was difficult.

The polysiloxane composition of Patent Document 2 is a gel-like substance that can be used as a resin composition for sealing an LED element, but the gel-like substance is not stable in its properties when the LED is lit, and has the purpose of protecting the light emitting element. It cannot be said that it is suitable in view of the fact that the curable resin composition for sealing should bear the burden. Further, since the system is internally cured by a dehydrogenation type reaction, there is a decisive problem that foaming occurs due to the influence of hydrogen gas produced as a by-product.

Further, in Patent Document 3, a silicone rubber composition to which a rare earth salt of 2-ethylhexanoic acid is added is used, and a silicone rubber composition using an addition type silicone resin composition utilizing the reaction of an alkenyl group and a hydrosilyl group is used. The invention is described.

JP-A-2002-18809 Patent No. 32777949 Patent No. 5422755

In recent years, the usage environment of semiconductor light emitting devices has expanded, and the required performance has been increasing. As for the sealing material, the required characteristics such as heat resistance, hardness, and changes in characteristics with time are becoming smaller, and crack resistance is becoming higher, and more excellent ones are required. An object of the present invention is to provide a curable polysiloxane composition that can be used as a sealing material that can withstand such high demands.

Therefore, as a result of diligent studies, the present inventors have used a platinum group metal catalyst and one or more compounds selected from the group consisting of an organic carboxylic acid metal salt and a cerium compound in combination with a dehydrogenation condensation type silicone resin. By doing so, it has been found that the crack resistance and the like can be greatly improved while suppressing the problem of foaming, and the present invention has been reached.

That is, the gist of the present invention is as follows.
(1) (A) a siloxane compound containing two or more silanol groups in one molecule, (B) a siloxane compound containing two or more hydrosilyl groups in one molecule, (C) a platinum group metal catalyst, and ( D) It contains an organic carboxylic acid metal salt and one or more compounds selected from the group consisting of a cerium compound, and has the total number of hydrosilyl groups of the compound of (B) and the compound of (A). The total molar ratio of silanol groups to SiH / SiOH is 1 to 20, and the metal content in the compound (D) is 1 ppm or more with respect to the total weight of the compound (A) and the compound (B). A curable polysiloxane composition.

More preferably
(2) The curable polysiloxane composition according to (1), which further contains (E) a reaction inhibitor;
(3) The curable polysiloxane composition according to (1) or (2), wherein the compound (D) contains a metal salt of 2-ethylhexanoic acid or octyl acid;
(4) The curable polysiloxane composition according to any one of (1) to (3), wherein the compound (D) contains cerium 2-ethylhexanoate;
(5) The curable polysiloxane composition according to any one of (1) to (4), wherein the refractive index at a temperature of 20 ° C. is 1.46 or less;
(6) Any of (1) to (5), wherein the compound (D) contains an organic carboxylic acid metal salt, and the organic carboxylic acid metal salt and the organic carboxylic acid coexist in the composition. The curable polysiloxane composition described in the above;
(7) A sealing material for a semiconductor light emitting device, which comprises the curable polysiloxane composition according to any one of (1) to (6);
(8) A semiconductor light emitting device provided with a cured product of the sealing material according to (7).

According to the present invention, it is possible to obtain a dehydrogenation condensation type curable polysiloxane composition which is excellent in heat resistance, light resistance, water heat resistance, UV resistance, particularly crack resistance, and further suppresses foaming.
Further, the cured product of the curable polysiloxane composition of the present invention has high light transmittance (transparency), light resistance, heat resistance, crack resistance, etc., and foaming is suppressed, so that it can be used for various optical members. It can be preferably used.

It is the schematic sectional drawing which shows one Embodiment of the semiconductor light emitting device.

Hereinafter, the present invention will be described in detail according to an embodiment. However, the present invention is not limited to the embodiments described expressly or implicitly herein.

<1. (A) A siloxane compound containing two or more silanol groups in one molecule>
In the present embodiment, as the component (A), a siloxane compound containing two or more silanol groups in one molecule is used.
A siloxane compound containing two or more silanol groups in one molecule acts as a main agent for curing the composition by a dehydrogenation condensation reaction with a siloxane compound containing two or more hydrosilyl groups in one molecule. It is a linear, branched, three-dimensional net-like organopolysiloxane having at least two or more silanol groups in one molecule.

The three-dimensional net-shaped organopolysiloxane also includes an MQ resin composed of M unit silicon and Q unit silicon, a DT resin composed of D unit silicon and T unit silicon, and the like. As the substituent of this siloxane compound, the same substituents as those of the organohydrogenpolysiloxane described later can be used, but those having no aliphatic unsaturated bond are preferable. Among them, the compound represented by the general formula (1) can be preferably used.

In the general formula (1), R is selected from the group consisting of unsubstituted or substituted monovalent hydrocarbon groups and hydroxyl groups, which may be the same or different from each other. Monovalent hydrocarbons include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, cyclohexyl, octyl, nonyl, decyl, alkenyl groups such as vinyl and allyl, and aryls such as phenyl. Groups, aralkyl groups such as 2-phenylethyl and the like can be mentioned. Furthermore, some of the hydrogen atoms in these hydrocarbon groups are substituted with other atoms or substituents, namely alkyl halides such as chloromethyl, aryl halides such as chlorophenyl, 3-. Examples thereof include a substituted hydrocarbon group such as an alkoxyalkyl group such as methoxypropyl and a cyanoalkyl group such as 3-cyanopropyl. Among these, preferred ones include a phenyl group, a methyl group and the like. 6 of R in the above formula
About 5% or more is preferably a methyl group, and more preferably 80% or more of R in the above formula is a methyl group. In particular, when UV resistance is required, it is more preferable that 99% or more of all organic groups excluding hydroxyl groups are methyl groups.

Specific examples thereof include hydroxy-terminal polydimethylsiloxane, and commercially available siloxane compounds containing two or more of these silanol groups in one molecule can be used. For example, hydroxy-terminal polydimethylsiloxane C96-723, XF3905, YF3057, YF3800, YF3802, YF3807, YF3897, etc. manufactured by Momentive Performance Materials Co., Ltd. can be mentioned.

The polystyrene-equivalent weight average molecular weight of the siloxane compound containing two or more silanol groups in one molecule is usually 500 or more, preferably 1000 or more, more preferably 5000 or more, and usually 150,000 or less, preferably 100,000 or less. More preferably, it is 80,000 or less. Below this range, the cured product may become hard and brittle. Further, if it exceeds this range, the composition may be difficult to cure.

As the siloxane compound containing two or more silanol groups in one molecule, one type may be used alone, or two or more types may be used in any combination and ratio.
The upper limit of the weight ratio of the component (A) to the total weight of the component (A) and the component (B) is usually 99%, preferably 97%, more preferably 95%, and the lower limit is usually 20%, preferably. It is 40%, more preferably 60%. If the weight ratio of the component (A) to the total weight of the component (A) and the component (B) is too large, the curing of the composition may be slowed down, or the hardness of the cured product may be low and the mechanical strength may be reduced. If the weight ratio of the component (A) to the total weight of the component (A) and the component (B) is too small, the cured product tends to be brittle.

<2. (B) A siloxane compound containing two or more hydrosilyl groups in one molecule>
The siloxane compound containing two or more hydrosilyl groups used as the component (B) in the present embodiment is an organohydrogen having at least two, preferably three or more SiH bonds in one molecule. Silane or linear, branched, three-dimensional net-like organohydrogenpolysiloxane. Of these, organohydrogenpolysiloxane is preferable because it does not easily volatilize during curing. As the substituent of this organohydrogenpolysiloxane, a group described later can be used, but one having no aliphatic unsaturated bond is preferable.

In the organohydrogenpolysiloxane, examples of the substituted or unsubstituted monovalent hydrocarbon group bonded to the silicon atom usually include those having 1 to 12 carbon atoms, preferably about 1 to 8 carbon atoms, and specifically, those having about 1 to 8 carbon atoms can be mentioned. Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group and other alkyl groups and phenyl groups. , Aryl group such as tolyl group, xsilyl group, naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl Alkenyl groups such as groups and octenyl groups, and those in which some or all of the hydrogen atoms of these groups are replaced with halogen atoms such as fluorine, bromine and chlorine, cyano groups and the like, for example, chloromethyl group, chloropropyl group and bromoethyl. Examples thereof include a halogen-substituted alkyl group such as a group and a trifluoropropyl group and a cyanoethyl group. Further, an alkoxy group having 1 to 3 carbon atoms within 3 wt% may be contained.

Examples of the organohydrogensilane and organohydrogenpolysiloxane include (CH ₃ ) SiH ₃ , (CH ₃ ) ₂ SiH ₂ , (C ₆ H ₅ ) SiH ₃ , 1,1,3,3-tetramethyldisiloxane. , 1,3,5,7-Tetramethylcyclotetrasiloxane, both-terminal trimethylsiloxy group-blocked methylhydrogenpolysiloxane, both-terminal trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both-terminal dimethylhydrogensiloxy Base-blocking dimethylpolysiloxane, both-terminal dimethylhydrogensiloxy group-blocking dimethylsiloxane / methylhydrogensiloxane copolymer, both-terminal trimethylsiloxy group-blocking methylhydrogensiloxane / diphenylsiloxane copolymer, both-terminal trimethylsiloxy group-blocking methylhydro Gensiloxane / diphenylsiloxane / dimethylsiloxane copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _{4/2 Examples} thereof include a copolymer composed of a unit and (C ₆ H ₅ ) SiO 3/2 unit.
Above all, the compound represented by the general formula (2) can be preferably used.

In the general formula (2), R ^{1 to} R ³ and R ^{5 to} R ⁸ each independently have a group selected from a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, and R ¹⁰ R ¹¹ R ^{12 Si.} Shown. R ⁴ and R ^{9 to} R ¹² each independently represent a group selected from a hydrogen atom, an alkyl group, an alkenyl group, and an aryl group. l represents an integer of 2 or more. m represents an integer of 0 or more.
Of R ^{1 to} R ¹² , at least 80 mol% or more, preferably 95 mol% or more, still more preferably 99 mol% or more is a methyl group.

The polystyrene-equivalent weight average molecular weight of the siloxane compound containing two or more hydrosilyl groups in one molecule is usually 300 or more, preferably 500 or more, more preferably 1000 or more, and usually 50,000 or less, preferably 20,000 or less. More preferably, it is 10,000 or less. Below this range, the cured product of the composition may become hard and brittle. On the other hand, if it exceeds this range, it may be difficult to uniformly cure the entire composition.
The upper limit of the hydrosilyl group content in the siloxane compound containing two or more hydrosilyl groups in one molecule is usually 20 mmol / g, preferably 15 mmol / g, more preferably 10 mmol / g, and the lower limit is usually 0.1 mmol / g. g, preferably 1 mmol / g, more preferably 3 mmol / g.

The upper limit of the weight ratio of the component (B) to the total weight of the component (A) and the component (B) is usually 70%, preferably 50%, more preferably 30%, and the lower limit is usually 0.5%. It is preferably 1%, more preferably 3%. If it is too large, the cured product tends to be brittle, and if it is too small, the curing of the composition may be slowed down, or the curing may be insufficient and the mechanical strength of the cured product may be reduced.
The total molar ratio of the total hydrosilyl group of the compound of the component (B) and the silanol group of the compound of the component (A) is 1 to 20. The lower limit of the molar ratio is preferably 1.5, more preferably 2, the upper limit is preferably 15, more preferably 10, and even more preferably 5. Even if the molar ratio is smaller than 1 or larger than 20, the composition tends to be insufficiently cured, and the remaining silanol groups and hydrosilyl groups increase, so that the cured product has heat resistance, light resistance, and crack resistance. Sex may be reduced.

<3. (C) Dehydrogenation condensation reaction catalyst (also called curing catalyst)>
The curable polysiloxane composition of the present embodiment contains (C) a platinum group metal catalyst as a dehydrogenation condensation reaction catalyst. Examples of the platinum group metal catalyst include platinum black, second platinum chloride, platinum chloride acid, a reaction product of platinum chloride acid and a monovalent alcohol, a complex of platinum chloride acid and olefins, and a platinum-based catalyst such as platinum bisacetoacetate. , Platinum-based catalyst, rhodium-based catalyst and the like. As a specific example, for example, a platinum-divinyltetramethyldisiloxane complex, a platinum-2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane complex and the like can be preferably used. it can.

The blending amount of the (C) platinum group metal catalyst can be the amount of the catalyst, but usually 0.5 ppm or more with respect to the total weight of the components (A) and (B) as the platinum group metal. It is preferably 1 ppm or more, usually 100 ppm or less, preferably 50 ppm or less, and more preferably 20 ppm or less. As a result, the catalytic activity can be increased.

One type of the platinum group metal catalyst may be used alone, or two or more types may be used in any combination and ratio. Further, it may be used in combination with any reaction promoter or reaction inhibitor.
Further, a siloxane compound dehydrogenation condensation reaction catalyst different from the platinum group metal catalyst may be used in combination, and examples thereof include metal complexes other than platinum group metals such as tin, titanium and aluminum, and aminoxy compounds containing hydroxylamine. Be done.
The content of the curing catalyst can be measured by ICP analysis.

<4. (D) Organic Carboxylic Acid Metal Salt or Cerium Compound>
The component (D) of the present embodiment is one or more compounds selected from the group consisting of an organic carboxylic acid metal salt and a cerium compound.
The metal of the organic carboxylic acid metal salt used as the component (D) is not particularly limited, and examples thereof include zinc, zirconium, iron, indium, nickel, manganese, lanthanum, samarium, praseodymium, neodymium, and cerium. Preferred metals are rare earth metals such as lanthanum, samarium, praseodymium, neodymium and cerium, and zirconium, indium and zinc, with cerium being particularly preferred.

The organic carboxylic acid of the organic carboxylic acid metal salt is not particularly limited, and examples thereof include a linear, branched or cyclic carboxylic acid having 4-10 carbon atoms, preferably 2-ethylhexanoic acid or octyl acid. is there. It is preferable that 2 to 4 of these are bonded to the above-mentioned metal, and more preferably the number of bonds to the metal is 3, that is, a trivalent metal. And the most preferable organic carboxylic acid metal salt is cerium 2-ethylhexanoate.

In the present embodiment, it is preferable that the organic carboxylic acid metal salt and the organic carboxylic acid coexist in the composition for the purpose of increasing the compatibility with silicone. The organic carboxylic acid coexisting in the composition may be an organic carboxylic acid of the same type as the organic carboxylic acid metal salt or a different type of organic carboxylic acid, but 2-ethylhexanoic acid or octyl acid is polysiloxane. It is preferable from the viewpoint of compatibility with. The amount of the organic carboxylic acid added is approximately 10 to 1000, where the amount of the organic carboxylic acid salt added is 100 (in terms of weight).

The metal of the organic carboxylic acid metal salt has a lower limit of 1 ppm, more preferably 10 ppm, based on the total weight of the components (A) and (B) of the present embodiment. If it is less than 1 ppm, a sufficient effect may not be exhibited. Further, the upper limit value is preferably 100 ppm, and when it is 100 ppm or less, high transparency can be maintained, which is preferable.

The cerium compound used as the component (D) of the present embodiment is not particularly limited as long as it can be added to the siloxane composition, but for example, an oxide such as cerium oxide, trivalent or tetravalent cerium. Inorganic salts such as carbonates, sulfates and phosphates, organic acid salts such as carboxylates, sulfonates and phosphonates, trivalent or tetravalent cerium ions as central metals, and alcohols and diketones. Examples thereof include a cerium complex as a ligand. Among them, an organic carboxylate and a diketone complex are preferable, and specific examples thereof include tris (acetylacetonato) cerium, cerium octylate, and cerium 2-ethylhexanoate. In addition, a compound overlapping with the above-mentioned organic carboxylic acid metal salt is also exemplified.

When the cerium compound is not soluble in silicone, it is preferable that the average particle size of the cerium compound is small because a high effect can be easily obtained. From the viewpoint of maintaining the transparency of the curable polysiloxane composition, the primary particle size of the cerium compound is preferably 100 nm or less, and the cerium compound is added to the polysiloxane composition in the form of a sol dispersed in a dispersion medium. May be good. The optimum range of the amount of cerium compound added depends on the solubility of the cerium compound in silicone and the particle size of the cerium compound in the case of insolubility. Therefore, the type and shape of the cerium compound, the particle size, and the case of sol May be appropriately selected according to the dispersed state and the like.

The amount of cerium in the cerium compound is 1 ppm, more preferably 10 ppm, as a lower limit value with respect to the total weight of the components (A) and (B) of the present embodiment. The upper limit is usually 10,000 ppm, and if it is larger than that, the transparency of the cured polysiloxane product may be significantly reduced.

In the present embodiment, the component (D) has the effect of significantly improving heat resistance, light resistance, crack resistance, etc. without significantly impairing the transparency of the cured polysiloxane product, and the (C) platinum group metal. When used in combination with a catalyst, it moderates the action of the platinum group metal catalyst, has the effect of controlling foaming due to hydrogen gas produced as a by-product in the curing reaction, and acts as a catalyst for the dehydration condensation reaction, promoting condensation between residual silanol groups. The effect can be expected.

<5. (E) Reaction inhibitor>
In the present embodiment, the curable polysiloxane composition is extended in usable time at room temperature, the reaction temperature of the dehydrogenation reaction is controlled to be higher, the generation temperature and rate of hydrogen gas are controlled, and the cured product is contained. It is preferable to add a reaction inhibitor for the purpose of suppressing the residual bubbles.
Examples of the reaction inhibitor used as the component (E) in the present embodiment include compounds containing an aliphatic unsaturated bond, and examples of the compound containing an aliphatic unsaturated bond include 3-hydroxy-3-3. Propagil alcohols such as methyl-1-butyne, 3,5-dimethyl-1-hexin-3-ol, 3-hydroxy-3-phenyl-1-butyne, 1-ethynyl-1-cyclohexanol, en-in Examples include compounds, maleic acid esters such as dimethylmalate, and the like. Among the compounds containing an aliphatic unsaturated bond, a compound having a triple bond is preferable.

The addition amount of the reaction inhibitor can be selected at various levels, the preferred amount of the lower limit is 10 ^-1 moles with respect to (C) a curing catalyst 1mol used, more preferably 1 mol, the upper limit of the preferable amount is 10 ³ moles, more preferably 10 ² moles. Further, these reaction inhibitors may be used alone or in combination of two or more.

<6. Other ingredients>
As other components, metal oxides as heat resistance improvers, flame retardant aids, conductivity imparting agents, antistatic agents, processing aids and the like can be used.
Further, an alkoxysilane-based compound containing an alkoxysilyl group, a silane coupling agent, a siloxane compound dehydration condensation catalyst such as titanium-based or zirconium-based, and the like can be blended as a cross-linking aid.
When the curable polysiloxane composition of the present embodiment is used as a sealing material for a semiconductor light emitting device, a phosphor or inorganic particles may be contained.

<7. Combined use of inorganic particles (filler)>
When an optical member characterized by containing at least a cured product of the curable polysiloxane composition of the present embodiment is used in a semiconductor light emitting device, in order to improve optical characteristics and workability, and below. Inorganic particles may be further contained for the purpose of obtaining the effect of any one of <1> to <5>.
<1> Inorganic particles are mixed as a light scattering substance in the cured product of the curable polysiloxane composition to scatter the light of the semiconductor light emitting device, thereby increasing the amount of light of the semiconductor light emitting element that hits the phosphor and improving the wavelength conversion efficiency. While improving it, the directivity angle of the light emitted from the semiconductor light emitting device to the outside is widened.
<2> By blending inorganic particles as a binder into the cured product of the curable polysiloxane composition, the occurrence of cracks is prevented.
<3> The viscosity of the composition liquid is increased by adding inorganic particles as a viscosity modifier to the curable polysiloxane composition.
<4> By blending inorganic particles with the cured product of the curable polysiloxane composition, its shrinkage is reduced.
<5> By blending inorganic particles into the cured product of the curable polysiloxane composition, the refractive index thereof is adjusted to improve the light extraction efficiency.
In this case, the curable polysiloxane composition may be mixed with an appropriate amount of inorganic particles according to the purpose, as in the case of the fluorescent powder.

Examples of the inorganic particles include silica fine particles, molten spherical silica, crushed silica, amorphous silica, quartz beads, glass beads, silicone particles, and the like. Among them, silica fine particles can be suitably used as a viscosity modifier, and the specific surface area by the BET method is usually 50 m ² / g or more, preferably 80 m ² / g or more, more preferably 80 m 2 / g or more, although it is not particularly limited. Is 100 m ² / g or more. Further, it is usually 300 m ² / g or less, preferably 200 m ² / g or less. If the specific surface area is too small, the effect of adding silica fine particles is not recognized, and if it is too large, the dispersion treatment in the resin tends to be difficult. As the silica fine particles, for example, those having a hydrophobic surface by reacting a silanol group existing on the surface of the hydrophilic silica fine particles with a surface modifier may be used.

Examples of the surface modifier include compounds of alkylsilanes, and specific examples thereof include dimethyldichlorosilane, hexamethyldisilazane, octylsilane, and dimethylsilicone oil.

Examples of the silica fine particles include fumed silica. Fused silica is produced by oxidizing and hydrolyzing _{SiCl 4} gas with a flame at 1100 to 1400 ° C. in which a mixed gas of _{H 2} and O _{2 is burned. The primary particles of fumed silica are spherical ultrafine particles mainly composed of amorphous silicon dioxide (SiO 2} ) having an average particle size of about 5 to 50 nm, and the primary particles are each aggregated to have a particle size. It forms secondary particles that are several hundred nm.

Since fumed silica is ultrafine particles and is produced by quenching, the surface structure is in a chemically active state.
Specifically, for example, "Aerosil" (registered trademark) manufactured by Nippon Aerosil Co., Ltd. is mentioned, and examples of hydrophilic Aerosil (registered trademark) are "90", "130", "150", "200", Examples of "300" and hydrophobic Aerosil (registered trademark) are "R8200", "R972", "R972V", "R972CF", "R974", "R202", "R".
805 ”,“ R812 ”,“ R812S ”,“ RY200 ”,“ RY200S ”,“ RX200 ”.
The content of the inorganic particles in the cured polysiloxane of the present embodiment is arbitrary as long as the effects of the present invention are not significantly impaired, but can be freely selected depending on the application form thereof. For example, when inorganic particles are used as a light scattering agent, the content thereof is preferably 0.01 to 10% by weight of the entire composition. Further, for example, when inorganic particles are used as an aggregate, the content thereof is preferably 1 to 80% by weight. Further, for example, when inorganic particles are used as a thickener (thixotropy), the content thereof is preferably 0.1 to 20% by weight. Further, for example, when inorganic particles are used as a refractive index adjusting agent, the content thereof is preferably 10 to 80% by weight. If the amount of the inorganic particles is too small, the desired effect may not be obtained, and if it is too large, various properties such as adhesion, transparency and hardness of the cured product may be adversely affected.

<8. Method for Producing Curable Polysiloxane Composition>
The curable polysiloxane composition of the present embodiment can be obtained by uniformly mixing the above-mentioned components. The mixing method is not particularly limited.
For this mixing, a mixer used for general silicone rubber preparation can be used, for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a Shinagawa mixer, a pressure kneader, a three-roll, two. This roll can be used.

<9. Refractive index of curable polysiloxane composition>
The refractive index of the curable polysiloxane composition of the present embodiment is such that the refractive index of light having a wavelength of 589 nm at a temperature of 20 ° C. of the curable polysiloxane composition is usually 1.56 or less, preferably 1.45 or less. More preferably, it is 1.42 or less, usually 1.35 or more, and preferably 1.40 or more. When applied to an optical member, a general light emitting device has a refractive index of about 2.5 or less, but it is preferable to select one having a relatively low refractive index from the viewpoint of the light stability of the resin.

The curable polysiloxane composition of the present embodiment has 80 mol% or more, preferably 95 mol% or more, more preferably 95 mol% or more of the substituents excluding the hydride group and the silanol group among all the substituents bonded to the silicon atom of the contained siloxane compound. Is preferably 99 mol% or more of an alkyl group. Further, the alkyl group is preferably a methyl group.
The refractive index of the curable polysiloxane composition of the present embodiment can usually be measured with a refractometer. Specifically, an Abbe refractometer (using a sodium D line (589 nm)) can be used.

<10. Characteristics of curable polysiloxane composition>
The viscosity of the curable polysiloxane composition of the present embodiment is not limited, but at a liquid temperature of 25 ° C., it is usually 20 mPa · s or more, preferably 100 mPa · s or more, more preferably 200 mPa · s or more, and usually 20000 mPa · s. It is s or less, preferably 10000 mPa · s or less, and more preferably 5000 mPa · s or less. The viscosity can be measured with an RV type viscometer (for example, an RV type viscometer "RVDV-II + Pro" manufactured by Brookfield Co., Ltd.).

<11. Combination with other members>
The curable polysiloxane composition of the present embodiment may be used alone, but may be mixed with another liquid medium for the purpose of adjusting properties such as viscosity, curing rate, hardness of the cured product, and ease of application. You may. As the liquid medium used, an inorganic material and / or an organic material can be used.
Examples of the inorganic material include a solution obtained by hydrolyzing and polymerizing a solution containing a metal alkoxide, a ceramic precursor polymer or a metal alkoxide by a sol-gel method, or an inorganic material obtained by solidifying a combination thereof (for example, siloxane bond). (Inorganic material having) and the like.
Examples of the organic material include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Specifically, for example, a methacrylic resin such as methyl polymethacrylate; a styrene resin such as polystyrene and a styrene-acrylonitrile copolymer; a polycarbonate resin; a polyester resin; a phenoxy resin; a butyral resin; a polyvinyl alcohol; ethyl cellulose and a cellulose acetate. , Cellulose-based resin such as cellulose acetate butyrate; epoxy resin; phenol resin; silicone resin and the like. In particular, when a high-power light emitting device such as lighting is required, it is preferable to use a silicon-containing compound for the purpose of heat resistance, light resistance, and the like.

A silicon-containing compound is a compound having a silicon atom in its molecule, and is a silicone-based material such as polyorganosiloxane, an inorganic material such as silicon oxide, silicon nitride, or silicon oxynitride, and borosilicate, phosphosilicate, and alkali silicate. Examples include glass materials such as silicate. Of these, silicone-based materials are preferable from the viewpoint of ease of handling and the like.
The silicone-based material usually refers to a polymer having a siloxane bond as a main chain, and examples thereof include a compound represented by the general composition formula (3) and / or a mixture thereof.
(R ²¹ R ²² R ²³ SiO _1/2 ) _M (R ²⁴ R ²⁵ SiO _2/2 ) _D (R ²⁶ SiO _3/2 ) _T (SiO _4/2 ) _Q ... Equation (3)
Here, R ²¹ to R ²⁶ may be the same or different, and are selected from the group consisting of an organic functional group, a silyl group, a hydroxyl group, and a hydrogen atom. Further, M, D, T and Q are 0 to less than 1, and are numbers satisfying M + D + T + Q = 1.

<12. Curing conditions>
The method for producing the cured polysiloxane composition of the present embodiment is not limited as long as it has a step of curing the curable polysiloxane composition of the present embodiment. When the polycondensate contains a solvent, the solvent may be distilled off in advance before drying.
The cured polysiloxane product of the present embodiment is usually cured in air at 150 ° C. within 6 hours, but preferable curing conditions are described in detail below. When the curing treatment is carried out at normal pressure, it is usually in the range of 15 ° C. or higher, preferably 50 ° C. or higher, more preferably 100 ° C. or higher, and usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 180 ° C. or lower. Do it at. It is also possible to carry out at a higher temperature by maintaining the liquid phase under pressure.
The curing time varies depending on the reaction temperature, but is usually 0.1 hours or more, preferably 0.5 hours or more, more preferably 0.8 hours or more, and usually 100 hours or less, preferably 20 hours or less, still more preferably 15. It will be carried out within the time range.

Under the above curing conditions, if the time is short or the temperature is too low, the polymerization may be insufficient and the strength of the cured product may be insufficient. On the other hand, if the time is too long or the temperature is too high, the molecular weight of the curable polysiloxane composition becomes high, the curing is too fast, the structure of the cured product becomes non-uniform, and cracks are likely to occur.
Further, when the curing temperature is set to a step-up temperature, foaming can be suppressed. The density of the cured polysiloxane at 25 ° C. of the present embodiment in which the residual air bubbles in the cured product is suppressed as much as possible is approximately 0.95 g / cm ³ or more.

<13. Embodiment of semiconductor light emitting device>
As an example of the optical member including at least the cured product of the polysiloxane of the present embodiment, a semiconductor light emitting device will be taken as an example, and the description will be made using the embodiment. In each of the following embodiments, the semiconductor light emitting device of this embodiment may be abbreviated as "light emitting device" as appropriate.
Further, the optical member used in the semiconductor light emitting device of the present embodiment will be referred to as a semiconductor light emitting device member. These embodiments are used for convenience of explanation only.
The example of the semiconductor light emitting device including at least the optical member of the present embodiment is not limited to these embodiments.

[Basic concept]
As the semiconductor light emitting device using the semiconductor light emitting device member according to the present embodiment, for example, there are application examples of the following A) and B). In any of the application examples, the member for a semiconductor light emitting device according to the present embodiment exhibits excellent light durability and thermal durability as compared with the optical member for a conventional semiconductor light emitting device, and cracks and peeling occur. It is difficult and there is little decrease in brightness. Therefore, the member for the semiconductor light emitting device according to the present embodiment is a member with high reliability for a long period of time.
A) A semiconductor light emitting device that uses the light emitting color of the light emitting element as it is.
B) A semiconductor in which a phosphor portion is arranged in the vicinity of the light emitting element, the phosphor and the phosphor component in the phosphor portion are excited by the light from the light emitting element, and light of a desired wavelength is emitted using fluorescence. Light emitting device.

In the application example of A), the high durability, transparency, and sealing material performance of the semiconductor light emitting device member according to the present embodiment are utilized, and the high durability sealing material, light extraction film, and various functionalities are used alone. It can be used as a component retaining material. In particular, when the semiconductor light emitting device member is used as a functional component holding material for holding the inorganic particles and the like and the semiconductor light emitting device member holds a transparent high refractive component, the semiconductor light emitting device member is used as a light emitting device. By using the light emitting element in close contact with the light emitting surface and setting the refractive index close to that of the light emitting element, it is possible to reduce the reflection of the light emitting element on the light emitting surface and obtain higher light extraction efficiency.

Further, also in the application example of B), the member for the semiconductor light emitting device according to the present embodiment can exhibit the same excellent performance as the application example of A) above, and also has a phosphor and a phosphor component. By holding the above, it is possible to form a phosphor portion having high durability and high light extraction efficiency. Further, when the member for the semiconductor light emitting device holds the transparent high refractive index component in addition to the phosphor and the phosphor component, the refractive index of the member for the semiconductor light emitting device is set to be close to the refractive index of the light emitting element or the phosphor. As a result, interfacial reflection can be reduced and higher light extraction efficiency can be obtained.

[A. Embodiments that do not use fluorescence]
[Embodiment A]
In the light emitting device 1A of the present embodiment, as shown in FIG. 1, the light emitting element 2 is surface-mounted on the insulating substrate 16 on which the printed wiring board 17 is provided. In the light emitting element 2, the p-type semiconductor layer (not shown) and the n-type semiconductor layer (not shown) of the light emitting layer portion 21 are electrically connected to the printed wirings 17 and 17 via the conductive wires 15 and 15, respectively. Has been done. The conductive wires 15 and 15 have a small cross-sectional area so as not to interfere with the light emitted from the light emitting element 2.
Here, as the light emitting element 2, an element that emits light of any wavelength from the ultraviolet to the infrared region may be used, but here, it is assumed that a gallium nitride based LED chip is used. Further, in this light emitting element 2, an n-type semiconductor layer (not shown) is formed on the lower surface side in FIG. 1 and a p-type semiconductor layer (not shown) is formed on the upper surface side, and light is output from the p-type semiconductor layer side. Will be described with the upper part of FIG. 1 as the front.

Further, a frame-shaped frame member 18 surrounding the light emitting element 2 is fixed on the insulating substrate 16, and a sealing portion 19 for sealing and protecting the light emitting element 2 is provided inside the frame material 18. The sealing portion 19 is formed of the transparent member 3A, which is a member for a semiconductor light emitting device of the present invention, and can be formed by potting with the above-mentioned curable polysiloxane composition.
Since the light emitting device 1A of the present embodiment includes the light emitting element 2 and the transparent member 3A, the light resistance and heat resistance of the light emitting device 1A can be improved. Further, since cracks and peeling are unlikely to occur in the sealing portion 3A, the transparency of the sealing portion 3A can be improved.

Further, it is possible to reduce the light color unevenness and the light color variation as compared with the conventional case, and it is possible to improve the efficiency of extracting light to the outside. That is, since the sealing portion 3A can be made highly transparent without fogging or turbidity, the uniformity of the light color is excellent, there is almost no variation in the light color between the light emitting devices 1A, and the light of the light emitting element 2 It is possible to improve the efficiency of taking out the light to the outside as compared with the conventional case. In addition, the weather resistance of the luminescent substance can be enhanced, and the life of the luminescent device 1A can be extended as compared with the conventional case.

[B. Embodiment using fluorescence]
[Embodiment B]
The configuration B of the embodiment can be the same as that of the embodiment A, except that a phosphor is appropriately added to the sealing portion 3A to form the phosphor portion. The type and amount of the phosphor added to the sealing portion 3A are appropriately selected according to the spectrum of the emitted light required for the semiconductor light emitting device. The phosphor portion may be arranged so as to be laminated on the upper part of the light emitting device 1A.

Hereinafter, the present invention will be described in more detail with reference to examples, but they are for the purpose of explaining the present invention and are not intended to limit the present invention to these aspects.
[Example 1]
(A) 100 parts by weight of polydimethylsiloxane (Si-OH: 0.13 mmol / g) with both ends sealed with silanol groups, (B) methylhydrosiloxane-dimethylsiloxane co-weight with both ends sealed with trimethylsilyl groups Combined (viscosity 20 mm ^{2 / s,} Si—H: 7.5 mmol / g) 7.23 parts by weight, (C) Momentive XC86-250 0.23 parts by weight as a platinum complex catalyst, (D-1) 2-ethyl 49% by weight of cerium hexanoate in 2-ethylhexanoic acid, 0.003 parts by weight of Ce (Wako Pure Chemical Industries, Ltd.) and 0.006 parts by weight of (E) 1-ethynyl-1-cyclohexanol were weighed and mixed. , A curable polysiloxane composition was obtained.
2.2 g of the curable polysiloxane composition was placed in a polytetrafluoroethylene petri dish having a diameter of 5 cm, degassed in a vacuum desiccator for several minutes, and then in an incubator at 100 ° C. for 1 hour and at 150 ° C. for 5 hours. It was held and an elastomeric cured product having a thickness of about 1 mm was obtained.

[Examples 2 to 6, Reference Example 1 , Comparative Examples 1 to 4]
A curable polysiloxane composition having the composition shown in Table 1 and an elastomeric cured product having a thickness of about 1 mm were obtained in the same manner as in Example 1 except that the following compound was used as the D component.
(D-1) Cerium 2-ethylhexanoate 49% in 2-ethylhexanoic acid, Ce 12% (Wako Pure Chemical Industries, Ltd.)
(D-2) 8% indium octylate (Shinshin Kagaku Kogyo Co., Ltd.)
(D-3) Zirconyl 2-ethylhexanoate in minor spirits (~ 6% Zr) (STREM CHEMICALS)
(D-4) Zinc Mineral Spirit Solution 2-Ethylhexanoate (Zn: 15%) (Wako Pure Chemical Industries, Ltd.)
(D-5) NanoTek Powder CeO ₂ (CI Kasei Co., Ltd.)
(D-6) UEP Zirconium Oxide ZrO ₂ (Daiichi Rare Element Chemical Industry Co., Ltd.)

Each test method shown in Table 1 is as follows.
[Shore A hardness]
The Shore A hardness was measured by stacking six pieces of an elastomeric cured product having a thickness of about 1 mm, which were radially divided into six equal parts from the center. The measured pieces were arranged in a circle on a Teflon (registered trademark) plate and held in an incubator at 230 ° C. for 500 hours, and then six pieces were stacked and the Shore A hardness was measured.
[Weight change]
After holding the elastomeric cured product having a thickness of about 1 mm in an incubator at 230 ° C. for 500 hours, the weight was measured and compared with the initial value.
[Crack test]
A 1/6 piece of an elastomeric cured product with a thickness of about 1 mm divided into 6 equal parts radially from the center is placed on an aluminum plate, held in an electric furnace at 260 ° C. for 24 hours, cooled to room temperature, and then cracked. Was visually observed.

In the comparative example, both the hardness change and the weight change after the lapse of 500 hours at 230 ° C. were large, and the crack test was generally NG. In Comparative Example 4 in which the amount of zirconium oxide added was large, there was no problem in the crack test, but the cured product was opaque.
In the composition to which an effective amount of Ce was added, the weight change after the lapse of 500 hours at 230 ° C. was remarkably small.

Claims (8)

(A) A siloxane compound containing two or more silanol groups in one molecule, (B) a siloxane compound containing two or more hydrosilyl groups in one molecule, (C) a platinum group metal catalyst, and (D) an organic Contains a carboxylic acid metal salt ,
The molar ratio SiH / SiOH of the total hydrosilyl groups of the compound (B) and the total silanol groups of the compound (A) is 1 to 20, and the metal in the compound (D). A curable polysiloxane composition having a content of 1 ppm or more based on the total weight of the compound (A) and the compound (B). The curable polysiloxane composition according to claim 1, further comprising (E) a reaction inhibitor. The curable polysiloxane composition according to claim 1 or 2, wherein the compound (D) contains a metal salt of 2-ethylhexanoic acid or octyl acid. The curable polysiloxane composition according to any one of claims 1 to 3, wherein the compound (D) contains cerium 2-ethylhexanoate. The curable polysiloxane composition according to any one of claims 1 to 4, wherein the refractive index at a temperature of 20 ° C. is 1.46 or less. The invention according to any one of claims 1 to 5, wherein the compound (D) contains an organic carboxylic acid metal salt, and the organic carboxylic acid metal salt and the organic carboxylic acid coexist in the composition. Curable polysiloxane composition. A sealing material for a semiconductor light emitting device, which comprises the curable polysiloxane composition according to any one of claims 1 to 6. A semiconductor light emitting device comprising the cured product of the sealing material according to claim 7.

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