JP6006554B2 - Addition-curable silicone composition, optical element sealing material comprising the composition, optical element sealed with the optical element sealing material, and method for producing addition-curable silicone composition - Google Patents

Description

  The present invention relates to an addition-curable silicone composition, an optical element sealing material comprising the composition, and an optical element sealed with the optical element sealing material.

  The addition-curable silicone composition contains a polyorganosiloxane containing a silicon-bonded hydrogen atom and an aliphatic unsaturated group such as an alkenyl group, and is crosslinked by a hydrosilylation reaction to give a cured product. The cured product thus obtained is excellent in heat resistance, cold resistance, and electrical insulation, and thus is used in various optical applications.

  Silicone compositions used for optical applications must adhere to optical elements and members used around optical elements such as silver and polyphthalamide, and are required to have high transparency and high heat discoloration.

  Furthermore, since the light-emitting element is repeatedly used for light emission and quenching, temperature changes frequently occur, and peripheral members are distorted. In particular, compositions that have been proposed so far as high-hardness materials cannot withstand expansion and contraction, and are liable to cause peeling and cracking from peripheral members (Patent Document 1).

  In order to prevent peeling, it is possible to use a primer composition (Patent Documents 2 and 3), but there are many cases where a solvent is used, and there is a problem that the number of processes increases, so it is better not to use it. preferable.

In order to prevent cracking, it is effective to use a high molecular weight silicone composition, but it is difficult to make the silicone composition have a low viscosity (Patent Document 4).
Further, a silicone resin composition for a light-emitting diode element that gives a cured product having high hardness and transparency and excellent light transmission at a low wavelength has been proposed (Patent Document 5). Since there is a distribution in the degree, further improvement in crack resistance has been desired.

JP 2009-215420 A JP 2004-339450 A JP 2008-179694 A JP 2011-246581 A JP 2004-221308 A

  The present invention has been made to solve the above problems, and is an addition-curable silicone composition that provides a cured product having high transparency, heat discoloration, high hardness, and excellent adhesion and crack resistance. It is an object of the present invention to provide an optical element sealing material comprising the composition, the composition, and an optical element sealed with the optical element sealing material.

（式中、Ｍｅはメチル基であり、ｉは２〜１０の整数である。式（１）で表わされる構造を有する化合物は実質的に分子量分布を有さない単一の化合物である。）
（Ｂ）下記平均組成式（２）で表され、２３℃で蝋状又は固体の三次元網状オルガノポリシロキサン樹脂を、上記（Ａ）成分中の全ケイ素原子結合水素原子に対して、（Ｂ）成分中のケイ素原子に結合したアルケニル基が、０．５〜５．０倍モルとなる量、
（Ｒ^２ _３ＳｉＯ_１／２）_ｋ（Ｒ^１Ｒ^２ _２ＳｉＯ_１／２）_ｍ（Ｒ^１ _２Ｒ^２ＳｉＯ_１／２）_ｎ（Ｒ^１ _３ＳｉＯ_１／２）_ｐ（Ｒ^１Ｒ^２ＳｉＯ）_ｑ（Ｒ^２ _２ＳｉＯ）_ｒ（Ｒ^１ＳｉＯ_３／２）_ｓ（Ｒ^２ＳｉＯ_３／２）_ｔ（ＳｉＯ_２）_ｕ…（２）
（式中、Ｒ^１は独立にアルケニル基を表し、Ｒ^２は独立に脂肪族不飽和結合を含まない有機基を表し、全Ｒ^２の少なくとも８０モル％はメチル基であり、１＞ｋ≧０、１＞ｍ≧０、１＞ｎ≧０、１＞ｐ≧０、１＞ｑ≧０、１＞ｒ≧０、１＞ｓ≧０、１＞ｔ≧０及び１＞ｕ≧０、並びにｍ＋ｎ＋ｐ＋ｑ＋ｓ＞０、ｓ＋ｔ＋ｕ＞０であり、かつｋ＋ｍ＋ｎ＋ｐ＋ｑ＋ｒ＋ｓ＋ｔ＋ｕ＝１を満たす数である。）
（Ｃ）白金族金属を含むヒドロシリル化触媒、
を含むことを特徴とする付加硬化型シリコーン組成物を提供する。 In order to achieve the above object, the present invention provides (A) a compound having a structure represented by the following formula (1),

(In the formula, Me is a methyl group, and i is an integer of 2 to 10. The compound having the structure represented by the formula (1) is a single compound having substantially no molecular weight distribution.)
(B) A three-dimensional network organopolysiloxane resin represented by the following average composition formula (2) and having a waxy or solid state at 23 ° C. is expressed as (B) with respect to all silicon-bonded hydrogen atoms in the component (A): ) The amount of the alkenyl group bonded to the silicon atom in the component is 0.5 to 5.0 times mol,
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ¹ ₂ R ² SiO _1/2 ) _n (R ¹ ₃ SiO _1/2 ) _p (R ¹ R ² SiO _Q (R ² ₂ SiO) _r (R ¹ SiO _3/2 ) _s (R ² SiO _3/2 ) _t (SiO ₂ ) _u (2)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an organic group not containing an aliphatic unsaturated bond, at least 80 mol% of all R ² is a methyl group, and 1> k ≧ 0, 1> m ≧ 0, 1> n ≧ 0, 1> p ≧ 0, 1> q ≧ 0, 1> r ≧ 0, 1> s ≧ 0, 1> t ≧ 0 and 1> u ≧ 0, And m + n + p + q + s> 0, s + t + u> 0, and k + m + n + p + q + r + s + t + u = 1.)
(C) a hydrosilylation catalyst containing a platinum group metal,
An addition-curable silicone composition is provided.

  A cured product obtained by crosslinking such an addition-curable silicone composition has high transparency and heat discoloration, and has high hardness and excellent adhesion and crack resistance. Therefore, LED, semiconductor laser, photo It can be suitably used as a sealing material for optical elements such as diodes, phototransistors, solar cells, and CCDs.

  The component (A) in the addition-curable silicone composition is preferably obtained by reacting a single molecular weight cyclic dimethylsiloxane, dimethylchlorosilane, and water.

  If it reacts in this way, (A) component with high purity can be obtained and crack resistance can be improved more.

  In this case, in the component (B) in the addition-curable silicone composition, 90 mol% or more of all organic groups bonded to silicon atoms other than alkenyl groups are preferably methyl groups.

  If 90 mol% or more is a methyl group, light resistance and weather resistance will become more excellent, and the hardened | cured material obtained will become more difficult to discolor.

  Moreover, it is preferable that the light transmittance in the wavelength of 400-800 nm of the hardened | cured material obtained by bridge | crosslinking the said addition curable silicone composition is 80% or more in thickness 1mm.

  Any cured product having the above light transmittance can be more suitably used as a sealing material for an optical element.

  An optical element sealing material comprising the above addition-curable silicone composition is provided.

  An optical element sealing material made of such an addition-curable silicone composition has high transparency and heat discoloration, and is excellent in adhesion and crack resistance while having high hardness. Can do.

  An optical element is provided which is sealed with a cured product of the optical element sealing material.

  Sealed with a cured product of such an optical element sealing material, it has high transparency and heat discoloration, and it is sealed with a sealing material that has high hardness and excellent adhesion and crack resistance. It becomes the optical element made.

  The cured product obtained by crosslinking the composition of the present invention is excellent in heat resistance, cold resistance and electrical insulation, has high transparency and heat discoloration, and has high hardness and adhesion and crack resistance. Since it is excellent, it can be suitably used as a sealing material for optical elements such as LEDs, semiconductor lasers, photodiodes, phototransistors, solar cells, and CCDs.

It is sectional drawing which shows typically an example of the light emitting semiconductor device with which the addition-curable silicone composition of this invention is used suitably.

Hereinafter, the present invention will be described in more detail.
As described above, conventionally used silicone compositions for optical applications have a problem that they cannot withstand expansion and contraction, and are liable to be peeled off or cracked from peripheral members.

  As a result of intensive studies, the inventor of the present invention uses a substantially single molecular weight oligodimethylsiloxane having silicon-bonded hydrogen atoms at both ends and crosslinks an unsaturated group-containing three-dimensional network polyorganosiloxane. The present inventors have found that an addition-curable silicone composition can be obtained that provides a cured product having high transparency, heat discoloration, and high hardness but excellent adhesion and crack resistance.

（式中、Ｍｅはメチル基であり、ｉは２〜１０の整数である。式（１）で表わされる構造を有する化合物は実質的に分子量分布を有さない単一の化合物である。）
（Ｂ）下記平均組成式（２）で表され、２３℃で蝋状又は固体の三次元網状オルガノポリシロキサン樹脂を、上記（Ａ）成分中の全ケイ素原子結合水素原子に対して、（Ｂ）成分中のケイ素原子に結合したアルケニル基が、０．５〜５．０倍モルとなる量、
（Ｒ^２ _３ＳｉＯ_１／２）_ｋ（Ｒ^１Ｒ^２ _２ＳｉＯ_１／２）_ｍ（Ｒ^１ _２Ｒ^２ＳｉＯ_１／２）_ｎ（Ｒ^１ _３ＳｉＯ_１／２）_ｐ（Ｒ^１Ｒ^２ＳｉＯ）_ｑ（Ｒ^２ _２ＳｉＯ）_ｒ（Ｒ^１ＳｉＯ_３／２）_ｓ（Ｒ^２ＳｉＯ_３／２）_ｔ（ＳｉＯ_２）_ｕ…（２）
（式中、Ｒ^１は独立にアルケニル基を表し、Ｒ^２は独立に脂肪族不飽和結合を含まない有機基を表し、全Ｒ^２の少なくとも８０モル％はメチル基であり、１＞ｋ≧０、１＞ｍ≧０、１＞ｎ≧０、１＞ｐ≧０、１＞ｑ≧０、１＞ｒ≧０、１＞ｓ≧０、１＞ｔ≧０及び１＞ｕ≧０、並びにｍ＋ｎ＋ｐ＋ｑ＋ｓ＞０、ｓ＋ｔ＋ｕ＞０であり、かつｋ＋ｍ＋ｎ＋ｐ＋ｑ＋ｒ＋ｓ＋ｔ＋ｕ＝１を満たす数である。）
（Ｃ）白金族金属を含むヒドロシリル化触媒、
を含むことを特徴とする付加硬化型シリコーン組成物である。 That is, the addition-curable silicone composition of the present invention is
(A) a compound having a structure represented by the following formula (1),

(In the formula, Me is a methyl group, and i is an integer of 2 to 10. The compound having the structure represented by the formula (1) is a single compound having substantially no molecular weight distribution.)
(B) A three-dimensional network organopolysiloxane resin represented by the following average composition formula (2) and having a waxy or solid state at 23 ° C. is expressed as (B) with respect to all silicon-bonded hydrogen atoms in the component (A): ) The amount of the alkenyl group bonded to the silicon atom in the component is 0.5 to 5.0 times mol,
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ¹ ₂ R ² SiO _1/2 ) _n (R ¹ ₃ SiO _1/2 ) _p (R ¹ R ² SiO _Q (R ² ₂ SiO) _r (R ¹ SiO _3/2 ) _s (R ² SiO _3/2 ) _t (SiO ₂ ) _u (2)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an organic group not containing an aliphatic unsaturated bond, at least 80 mol% of all R ² is a methyl group, and 1> k ≧ 0, 1> m ≧ 0, 1> n ≧ 0, 1> p ≧ 0, 1> q ≧ 0, 1> r ≧ 0, 1> s ≧ 0, 1> t ≧ 0 and 1> u ≧ 0, And m + n + p + q + s> 0, s + t + u> 0, and k + m + n + p + q + r + s + t + u = 1.)
(C) a hydrosilylation catalyst containing a platinum group metal,
It is an addition-curable silicone composition characterized by including.

Hereinafter, each component will be described in detail. In the present specification, Me represents a methyl group, and Vi represents a vinyl group.
The composition of the present invention contains the following components (A) to (C).

（式中、Ｍｅはメチル基であり、ｉは２〜１０の整数である。式（１）は実質的に分子量分布を有さない単一の化合物である。） [(A) component]
The component (A) is a component that lowers the viscosity of the resulting addition-curable silicone composition and causes stress relaxation after the addition-curable silicone composition is cured. The component (A) is a compound represented by the following formula (1).

(In the formula, Me is a methyl group, and i is an integer of 2 to 10. Formula (1) is a single compound having substantially no molecular weight distribution.)

In this case, i is preferably from 3 to 10, more preferably from 4 to 8. When i is less than 2, volatilization is likely to occur, and the storage stability of the composition may decrease. When it exceeds 10, it is industrially difficult to obtain a single compound having substantially no molecular weight distribution. In addition, the hardness of the cured product of the composition may be lowered.
In the present invention, the single compound having substantially no molecular weight distribution means that the purity of the single compound (A) is 90% by mass or more, preferably 95% by mass or more in gas chromatography analysis. Particularly preferred is 97% by mass or more.
When the purity of the component (A) is less than 90% by mass, the crack resistance may be lowered.

  Conventionally, a compound having a structure such as formula (1) is made from a cyclic siloxane such as octamethylcyclotetrasiloxane and an end-capping agent such as 1,3-dihydrogentetramethyldisiloxane in the presence of an acid. An equilibrium reaction was obtained. In this method, a mixture of components having different degrees of polymerization is obtained, a molecular weight distribution is obtained, and a material having a low degree of polymerization also contains a cyclic product, resulting in a mixture having a wide distribution, which is difficult to separate even by distillation. One compound was not contained in 90 mass% or more.

  However, in the above composition, when a silicone composition obtained by the above conventional synthesis method is used, the low molecular component volatilizes during preparation and heat curing, and the crack resistance and the like are not sufficiently satisfied.

On the other hand, when an oligosiloxane having both molecular ends substantially free of molecular weight distribution and blocked with SiH groups is used as in the present invention, there is no high molecular weight body or low molecular weight body. Etc. are excellent.
Examples of the method for synthesizing the component (A) include a method in which a single molecular weight cyclic dimethylsiloxane purified by distillation or the like is reacted with water, preferably dimethylchlorosilane in the presence of an inorganic solid compound such as silica gel. The product obtained may be distilled if necessary.

As a specific example of the component (A),
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₂ ,
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₄ ,
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₆ ,
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₈ ,
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₉ ,
(HMe ₂ SiO _1/2 ) ₂ (Me ₂ SiO) ₁₀
Etc.

[Component (B)]
The component (B) is a component for increasing the hardness while maintaining the transparency of the cured product.
The component (B) is represented by the following average composition formula (2), and in the molecule of waxy or solid at 23 ° C., an alkenyl group and a trifunctional siloxane unit and / or SiO _4/2 unit are essential. Is a three-dimensional network-like organopolysiloxane resin.
In addition, “wax” means a gum (raw rubber) that shows no self-fluidity at 23 ° C. of 10,000,000 mPa · s or more, particularly 100,000,000 mPa · s or more. means.

(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ¹ ₂ R ² SiO _1/2 ) _n (R ¹ ₃ SiO _1/2 ) _p (R ¹ R ² SiO ) _Q (R ² ₂ SiO) _r (R ¹ SiO _3/2 ) _s (R ² SiO _3/2 ) _t (SiO ₂ ) _u (2)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an organic group not containing an aliphatic unsaturated bond, at least 80 mol% of all R ² is a methyl group, and 1> k ≧ 0, 1> m ≧ 0, 1> n ≧ 0, 1> p ≧ 0, 1> q ≧ 0, 1> r ≧ 0, 1> s ≧ 0, 1> t ≧ 0 and 1> u ≧ 0, And m + n + p + q + s> 0, s + t + u> 0, and k + m + n + p + q + r + s + t + u = 1.)

The alkenyl group bonded to the silicon atom (R ¹ in the above formula (2)) has 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is preferable.

In the organopolysiloxane resin of component (B), the organic group bonded to the silicon atom other than the aliphatic unsaturated bond (R ² in the above formula (2)) does not have an aliphatic unsaturated bond. There is no particular limitation as long as it is, for example, unsubstituted or substituted, the number of carbon atoms is 1 to 12, preferably 1 to 10 hydrocarbons. Examples of the unsubstituted or substituted hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group; a cycloalkyl group such as a cyclohexyl group; a phenyl group, Aryl groups such as tolyl, xylyl and naphthyl groups; aralkyl groups such as benzyl and phenethyl groups; some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as chlorine, fluorine and bromine In addition, halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group and the like can be mentioned, preferably an alkyl group, more preferably a methyl group.

In the component (B), if 80 mol% or more of all organic groups bonded to the silicon atom other than the organic group represented by R ² that does not contain an aliphatic unsaturated bond, that is, an alkenyl group, is a methyl group, light resistance Properties and weather resistance are not deteriorated, and the cured product is less likely to discolor.
In this case, 90 mol% or more of all organic groups bonded to the silicon atom other than the alkenyl group is more preferably a methyl group, and more preferably 98 to 100 mol% is a methyl group.

k is 0 to 0.65, m is 0 to 0.65, n is 0 to 0.65, p is 0 to 0.65, q is 0 to 0.5, r is 0 to 0.5, s is 0 to 0.8, t is preferably 0 to 0.8, and u is preferably a number from 0 to 0.6. Further, m + n + q is preferably a number of 0.01 to 0.50, particularly 0.05 to 0.20, and m + n + p + q + s is a number of 0.01 to 0.50, particularly 0.05 to 0.20. It is preferable that s + t + u is a number of 0.1 to 0.8, particularly 0.2 to 0.6.
The weight average molecular weight in terms of polystyrene in GPC (gel permeation chromatograph) measured using tetrahydrofuran as the developing solvent for the organopolysiloxane resin of component (B) is preferably 400 to 100,000, particularly 500 to Preferably it is 50,000.

  In the component (B), the content of the alkenyl group bonded to the silicon atom is preferably in the range of 0.01 to 1 mol, and in the range of 0.05 to 0.5 mol, per 100 g of the component (B). Is more preferable. When the content of the alkenyl group satisfies the range of 0.01 to 1 mol, the crosslinking reaction proceeds sufficiently, and a cured product with high hardness can be obtained.

As the organopolysiloxane resin as the component (B), for example, those represented below are preferable.
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (SiO ₂ ) _u
(R ¹ R ² ₂ SiO _1/2 ) _m (SiO ₂ ) _u
(R ¹ R ² SiO) _q (R ² ₂ SiO) _r (R ² SiO _3/2 ) _t
(R ¹ R ² ₂ SiO _1/2 ) _m (R ² ₂ SiO) _r (R ¹ SiO _3/2 ) _s
(R ¹ R ² ₂ SiO _1/2 ) _m (R ² ₂ SiO) _r (R ² SiO _3/2 ) _t
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ² ₂ SiO) _r (R ² SiO _3/2 ) _t
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ¹ R ² SiO) _q (R ² ₂ SiO) _r (R ² SiO _3/2 ) _t
(In the formula, R ¹ , R ² , k, m, n, p, q, r, s, t, and u are as defined in the average composition formula (2).)

As a specific example of the component (B),
(Me ₃ SiO _1/2 ) _k (ViMe ₂ SiO _1/2 ) _m (SiO ₂ ) _u,
(ViMeSiO) _q (Me ₂ SiO) _r (MeSiO _3/2 ) _t ,
(ViMe ₂ SiO _1/2 ) _m (Me ₂ SiO) _r (MeSiO _3/2 ) _t
Etc.
(B) A component may be used individually by 1 type, or may use 2 or more types together.

  The blending ratio of the component (B) to the component (A) is preferably 0.5 to 5 for alkenyl groups bonded to silicon atoms in the component (B) with respect to all silicon atom-bonded hydrogen atoms in the component (A). It is the amount which becomes 0.0 times mole. The amount is more preferably 0.6 to 3.0 times mol, and particularly preferably 0.8 to 2.0 times mol. The mass ratio of the component (A) to the component (B) is preferably 1:99 to 50:50, more preferably 5:95 to 40:60, and particularly preferably 10:90 to 30:70.

[Component (C)]
The platinum group metal catalyst which is the component (C) is a component for proceeding and promoting the hydrosilylation reaction of the components (A) and (B). The platinum group metal catalyst is not particularly limited. For example, platinum group metals such as platinum, palladium, rhodium; chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid and olefins, vinyl siloxane, or acetylene compounds And platinum group metal compounds such as platinum compounds such as coordination compounds, tetrakis (triphenylphosphine) palladium, chlorotris (triphenylphosphine) rhodium, etc., but are compatible with the components (A) and (B). Since it is good and contains almost no chloro impurities, a chloroplatinic acid modified with silicone is preferred. Furthermore, it is preferable to dissolve in silicone oil in advance and mix with the components (A) and (B).
(C) A component may be used individually by 1 type, or may use 2 or more types together.

  The compounding amount of the component (C) may be a catalytic amount, but is usually 0.1 to 1000 ppm in terms of the mass of the platinum group metal element with respect to the sum of the components (A) and (B), preferably 1 to 1 ppm. 500 ppm, more preferably 3 to 100 ppm.

[Other ingredients]
The addition-curable silicone composition of the present invention can contain other components exemplified below in addition to the components (A) to (C).

  Other components include, for example, a light scattering agent or reinforcing material such as silica and titanium oxide; a phosphor; a reactive solvent such as a petroleum solvent, a silicone oil having an alkenyl group such as a vinyl group; and a reactive functional group. Viscosity modifier such as non-reactive silicone oil; carbon functional silane, epoxy group, alkoxy group, hydrogen atom bonded to silicon atom (ie, SiH group) and alkenyl group such as vinyl group bonded to silicon atom Adhesion improvers such as silicone compounds other than the components (A) and (B) having at least one of the above; reaction inhibitors such as ethynylcyclohexanol and tetramethyltetravinyltetracyclosiloxane; In this case, the adhesion improver is preferably 0.1 to 20 parts by mass, particularly 0.2 to 10 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B). It is preferable that a control agent is 0.001-5 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, especially 0.1-2 mass parts. These other components may be used alone or in combination of two or more.

[Addition-curing type silicone composition]
In the components (A) and (B) in the addition-curable silicone composition of the present invention, 80 mol% or more (80 to 100 mol%) of all monovalent hydrocarbon groups bonded to silicon atoms other than aliphatic unsaturated bonds ) In particular, 90 mol% or more (90 to 100 mol%) is a methyl group, which is excellent in heat resistance and light resistance (ultraviolet light resistance), and for deterioration including discoloration due to thermal and ultraviolet stress. It is preferable because of its excellent resistance.

[Preparation method]
The addition-curable silicone composition of the present invention can be prepared by mixing the above-mentioned other components with the components (A) to (C) or the components (A) to (C). In this case, for example, in order to ensure sufficient storage stability, the part containing the component (A) and the part containing the component (C) are prepared separately, and these two parts are mixed and used at the time of use. You can also

[Curing conditions]
Curing of the addition-curable silicone composition of the present invention may be performed under known conditions and may be performed at room temperature, but is preferably heated to increase the curing rate, for example, at 60 to 180 ° C. for 1 minute to 5 hours. It is preferable to heat to a certain extent.
Further, the Shore D hardness of the cured product obtained by curing the addition curable silicone composition is more preferably 20 or more, more preferably 25 to 90, and particularly preferably 30 to 70 from the strength aspect.

  The light transmittance at a wavelength of 400 to 800 nm of a cured product obtained by crosslinking the addition-curable silicone composition is preferably 80% or more, particularly 90% or more at a thickness of 1 mm.

[Usage]
In the present invention, the above addition-curable silicone composition can be used as an optical element sealing material.

  The addition-curable silicone composition of the present invention is useful as a sealing material for optical elements, particularly LED elements, and the optical element sealing material comprising the addition-curable silicone resin composition of the present invention is effective for optical elements. Can be sealed.

  An optical element sealed with a cured product of the optical element sealing material has high transparency and heat discoloration, and has excellent adhesion and crack resistance while having high hardness.

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

  In the following examples, the viscosity is a value measured at 25 ° C. using a rotational viscometer.

  In the following examples, the hardness is a value measured at 25 ° C. using a Shore D hardness meter.

  In the following example, the light transmittance is a value obtained by measuring the transmittance at a wavelength of 400 nm at 25 ° C. using a spectrophotometer.

In the following examples, symbols indicating the composition of silicone oil or silicone resin are shown below. The number of moles of each silicone oil or each silicone resin indicates the number of moles of vinyl groups or silicon atom-bonded hydrogen atoms contained in each component.
M: (CH ₃ ) ₃ SiO _1/2
^MH : (CH ₃ ) ₂ HSiO _1/2
M ^Vi : (CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2
D: (CH ₃ ) ₂ SiO _{2/2
^{D H: (CH 3) HSiO}} 2/2
Q: SiO _4/2

In the following examples, (B) component is composed of a M units and ^{M Vi} units and Q ^units, a 6.0 molar ratio of M units to ^{M Vi} units, and M units and ^{M Vi} to Q units A silicone resin (resin A) having a total molar ratio of 1.0 and a vinyl group content of 0.10 mol / 100 g was used. Since Resin A is a solid at room temperature, it was mixed with a xylene solution to make it uniform with other silicones.

[Preparation Example 1] Preparation of platinum catalyst The platinum catalyst used in this example is a reaction product of hexachloroplatinic acid and sym-tetramethyldivinyldisiloxane, and the platinum content is 0.05. It is diluted with liquid dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of 60 mPa · s so as to be mass% (catalyst a).

[Preparation Example 2] Synthesis was carried out as follows with reference to a synthesis document of ^MH ₂ D ₆ (Chemistry Letters 1990, 11, 1233-2136).
In a 1 L flask, 200 g of dodecamethylcyclohexasiloxane, 200 g of hexane, 146 g of water and 10 g of silica gel (Kieselgel 60 manufactured by Merck Co., Ltd.) were added and stirred, and 255 g of dimethylchlorosilane was added dropwise under ice cooling. After completion of the dropwise addition, stirring was continued for 1 hour at room temperature. The silica gel was filtered and excess dimethylchlorosilane was distilled off, followed by washing with 200 g of water twice. Then, 1,15-dihydrogenhexadecamethyloctasiloxane ( ^MH ₂ D ₆ ), which is a single compound, was obtained by distillation under reduced pressure. As a result of gas chromatography analysis, the purity of ^MH ₂ D ₆ was 98.5% by mass.

[Preparation Example 3] Synthesis of ^MH ₂ D ₈ 1,19-dihydrogeneico which is a single compound by reacting hexadecamethylcyclooctasiloxane and dimethylchlorosilane as raw materials in the same manner as in Preparation Example 2 above. Samethyl decasiloxane was obtained. As a result of gas chromatography analysis, the purity of ^MH ₂ D ₈ was 98.3 mass%.

[Comparative Preparation Example 1] Synthesis of Average Composition M ^H ₂ D _{8 For} comparison, a compound having the same average composition as the compound obtained in Preparation Example 3 was synthesized by a conventional method. That is, 442 g of octamethylcyclotetrasiloxane and 100 g of 1,3-dihydrogentetramethyldisiloxane were placed in a 1 L flask and stirred, and 0.2 g of trifluoromethanesulfonic acid was added dropwise. After stirring for 8 hours at room temperature, 1.0 g of a neutralizing agent (KYOWARD 500 manufactured by Kyowa Chemical Industry Co., Ltd.) was mixed and neutralized for 2 hours. The neutralizing agent was removed by filtration, and an average composition ^MH ₂ D ₈ was obtained. As a result of gas chromatography analysis, this was a mixture having a wide distribution, and the content of ^MH ₂ D ₈ itself was 12.7% by mass.

  Silicones represented by other average compositions were similarly prepared by equilibration with acid or alkali.

[Example 1]
22.5 g of a silicone oil having the structure of ^MH ₂ D ₆ obtained in Preparation 2 (77.7 mmol of hydrogen atoms bonded to silicon atoms) and 77.5 g of resin A (77.5 vinyl groups bonded to silicon atoms) The xylene was removed under a reduced pressure of 100 mm and 8 mmHg. The resulting liquid was mixed with 0.05 g of ethynylcyclohexanol, 1 g of γ-glycidoxypropyltrimethoxysilane, and 1 g of catalyst a to obtain a silicone composition. Table 1 shows the viscosity of the silicone composition, the hardness when heated at 150 ° C. for 4 hours, and the light transmittance of 1 mm thickness.

[Example 2]
26.7 g of a silicone oil having the structure of ^MH ₂ D ₈ obtained in Preparation 3 (73.4 mmol of hydrogen atoms bonded to silicon atoms) and 73.3 g of resin A (vinyl group 73.3 bonded to silicon atoms) The xylene was removed under a reduced pressure of 100 mm and 8 mmHg. The resulting liquid was mixed with 0.05 g of ethynylcyclohexanol, 1 g of γ-glycidoxypropyltrimethoxysilane, and 1 g of catalyst a to obtain a silicone composition. Table 1 shows the viscosity of this composition, the hardness when heated at 150 ° C. for 4 hours, the light transmittance of 1 mm thickness, and the temperature cycle test results.

[Comparative Example 1]
Instead of the silicone oil obtained in Preparation Example 3, 26.7 g of a silicone oil having a structure of average composition ^MH ₂ D ₈ obtained in Comparative Adjustment Example 1 (73.4 mmol of hydrogen atoms bonded to silicon atoms) A silicone composition was obtained in the same manner as in Example 2 except that. Table 1 shows the viscosity of this composition, the hardness when heated at 150 ° C. for 4 hours, the light transmittance of 1 mm thickness, and the temperature cycle test results.

[Comparative Example 2]
Silicone oil 42.4 g (57.7 mmol of hydrogen atoms bonded to silicon atoms) having a structure of an average composition ^MH ₂ D ₁₈ having a molecular weight distribution synthesized in the same manner as in Comparative Preparation Example 1 and 57.6 g of Resin A (silicon A 50 wt% xylene solution of 57.6 mmol of vinyl groups bonded to the atoms was mixed, and xylene was removed at 100 ° C. under a reduced pressure of 8 mmHg. The resulting liquid was mixed with 0.05 g of ethynylcyclohexanol, 1 g of γ-glycidoxypropyltrimethoxysilane, and 1 g of catalyst a to obtain a silicone composition. Table 1 shows the viscosity of this composition, the hardness when heated at 150 ° C. for 4 hours, the light transmittance of 1 mm thickness, and the temperature cycle test results.

[Comparative Example 3]
A silicone composition was obtained in the same manner as in Example 1, except that 56.9 g of silicone oil having a structure of average composition M ^Vi ₂ D ₄₀ (77.5 mmol of vinyl group bonded to silicon atom) was used instead of Resin A. It was. Table 1 shows the viscosity of this composition, the hardness when heated at 150 ° C. for 4 hours, the light transmittance of 1 mm thickness, and the temperature cycle test results.

[Comparative Example 4]
A mixture of 7.4 g (92.0 mmol) of silicone oil having a structure of average composition M ₂ ^DH ₈ and 50 wt% xylene solution of 92.6 g (92.6 mmol) of Resin A was mixed at 100 ° C. under a reduced pressure of 8 mmHg. Xylene was removed. However, after distilling off xylene, it became solid and it was impossible to obtain an addition-curable silicone composition.

[Comparative Example 5]
A mixture of 26.7 g (332.0 mmol) of silicone oil having a structure of average composition M ₂ ^DH ₈ and 50 wt% xylene solution of 73.3 g (73.3 mmol) of Resin A was mixed at 100 ° C. under a reduced pressure of 8 mmHg. Xylene was removed. The resulting liquid was mixed with 0.05 g of ethynylcyclohexanol, 1 g of γ-glycidoxypropyltrimethoxysilane, and 1 g of catalyst a to obtain a silicone composition. Table 1 shows the viscosity of the composition, the hardness when heated at 150 ° C. for 4 hours, and the light transmittance of 1 mm.

The evaluation method of the silicone composition prepared in the above Examples and Comparative Examples was performed as follows.
[Evaluation method]
Light-Emitting Semiconductor Package As a light-emitting element, a light-emitting semiconductor device as shown in FIG. 1 having a light-emitting layer made of InGaN and having an LED chip with a main light emission peak of 470 nm was used. The light emitting element 2 was fixed to the housing 1 having a pair of lead electrodes 3 and 4 using a die bond material 5. After the light emitting element 2 and the lead electrodes 3 and 4 were connected by the gold wire 6, the sealing material (sealing resin) 7 was potted and cured. The curing condition of the sealing material (sealing resin) 7 is 150 ° C. and 4 hours.

[Test method for temperature cycle resistance]
Ten manufactured light-emitting semiconductor devices were passed through an infrared reflow device (260 ° C.) three times, and thereafter a temperature cycle of −40 ° C. to 100 ° C. for 30 minutes was performed 100 times. Changes in the appearance were observed, and those in which cracking of the sealing material (sealing resin) and peeling from the LED package were confirmed were counted as NG (see Table 1).

As shown in Table 1, it can be seen that by satisfying the conditions of the present invention, a composition having a high hardness and a high resistance to a temperature cycle test can be obtained. In contrast, in Comparative Example 1 in which the component (A) was changed to one having a molecular weight distribution synthesized by acid equilibrium (equilibrium reaction) , the NG number of the temperature cycle test was 2. In Comparative Examples 2 and 3, the hardness was extremely reduced. In Comparative Example 4, it was impossible to prepare the obtained composition. Moreover, when the composition containing the component which has three or more silicon atom bond hydrogen atoms used conventionally like the comparative example 5 was used, it was confirmed that temperature cycle tolerance deteriorates.

  From the above results, the addition-curable silicone resin composition of the present invention is excellent in heat resistance, cold resistance, and electrical insulation, and has high transparency and high hardness despite its high hardness. Since the cured product having excellent crack resistance against thermal shock can be provided, the optical element sealing material comprising the addition-curable silicone resin composition of the present invention is subjected to severe temperature cycles that repeat light emission and quenching. It is useful as a sealing material for the optical element provided, and an optical element sealed with a cured product of such an optical sealing material has excellent heat resistance, high hardness and excellent crack resistance. It was proved that.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  DESCRIPTION OF SYMBOLS 1 ... Housing | casing 2 ... Light emitting element 3, 4, ... Lead electrode, 5 ... Die-bonding material, 6 ... Gold wire, 7 ... Sealing material (sealing resin).

Claims (6)

(A) a compound having a structure represented by the following formula (1),

(In the formula, Me is a methyl group and i is an integer of 2 to 10. The compound having the structure represented by the formula (1) is a single compound having substantially no molecular weight distribution, ( A) The purity of a single compound as a component is 90% by mass or more in gas chromatography analysis.)
(B) A three-dimensional network organopolysiloxane resin represented by the following average composition formula (2) and having a waxy or solid state at 23 ° C. is expressed as (B) with respect to all silicon-bonded hydrogen atoms in the component (A): ) The amount of the alkenyl group bonded to the silicon atom in the component is 0.5 to 5.0 times mol,
(R ² ₃ SiO _1/2 ) _k (R ¹ R ² ₂ SiO _1/2 ) _m (R ¹ ₂ R ² SiO _1/2 ) _n (R ¹ ₃ SiO _1/2 ) _p (R ¹ R ² SiO _Q (R ² ₂ SiO) _r (R ¹ SiO _3/2 ) _s (R ² SiO _3/2 ) _t (SiO ₂ ) _u (2)
(Wherein R ¹ independently represents an alkenyl group, R ² independently represents an organic group not containing an aliphatic unsaturated bond, at least 80 mol% of all R ² is a methyl group, and 1> k ≧ 0, 1> m ≧ 0, 1> n ≧ 0, 1> p ≧ 0, 1> q ≧ 0, 1> r ≧ 0, 1> s ≧ 0, 1> t ≧ 0 and 1> u ≧ 0, And m + n + p + q + s> 0, s + t + u> 0, and k + m + n + p + q + r + s + t + u = 1.)
(C) a hydrosilylation catalyst containing a platinum group metal,
An addition curable silicone composition comprising: a siloxane having SiH groups contained in the composition, wherein the proportion of the single compound is 90% by mass or more. . A method for producing an addition-curable silicone composition according to claim 1,
The component (A) of the addition-curable silicone composition, a step of synthesizing by reacting a cyclic dimethylsiloxane and dimethylchlorosilane with water of a single molecular weight,
Mixing the synthesized component (A), the component (B), and the component (C) to produce an addition-curable silicone composition;
A method for producing an addition-curable silicone composition, comprising: In component (B) of the addition-curable silicone composition, at least 90 mol% of all organic groups bonded to silicon atoms other than the alkenyl groups, the addition according to claim 1, characterized in that a methyl group A curable silicone composition. Addition curing according to claim 1 or 3 wherein the light transmittance in 400~800nm wavelength of the addition-curable silicone composition a cured product obtained by cross-linking, characterized in that at least 80% at a thickness of 1mm Type silicone composition. An optical element sealing material comprising the addition-curable silicone composition according to any one of claims 1 to 3 .   An optical element sealed with a cured product of the optical element sealing material according to claim 5.

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