JP4876732B2 - Epoxy resin composition, cured product thereof, and optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition that gives a cured product less likely to be discolored and excellent in crack resistance and transparency, to provide a cured product of the epoxy resin composition and to provide a photosemiconductor device. <P>SOLUTION: The epoxy resin composition comprises an epoxy resin, a polyvalent carboxylic acid anhydride and a dendritic polymer. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an epoxy resin composition, a cured product thereof, and an optical semiconductor device. More specifically, the present invention relates to an epoxy resin composition that gives a cured product with little coloring and excellent crack resistance and transparency, the cured product, and an optical semiconductor device.

  Generally, epoxy resin cured products obtained from acid anhydrides and epoxy resins are inexpensive and have excellent transparency, electrical insulation, chemical resistance, moisture resistance, adhesiveness, etc., electrical insulation materials, semiconductor materials, adhesives It is used in various applications such as materials and paint materials. As a typical use example, a sealing material for protecting a light-emitting element of a light-emitting diode (hereinafter abbreviated as an LED) can be given. As white LEDs that combine a light source that emits light and a phosphor have become widespread, degradation of sealing materials has become a problem.

  That is, in the case of a white LED, since a higher energy light source is used, there is a problem that the sealing material is degraded and easily colored as compared with a conventional red or green LED, and the life of the LED is shortened. . In addition, as the size of the light emitting element is improved and the current is increased, the heat generated when the LED is lit for a long time is increased, which also causes deterioration of the sealing material.

  Suppressing such deterioration due to light and heat is an important issue in the further spread of epoxy resins. As a method for solving this problem, there has been proposed an epoxy resin composition using an alicyclic epoxy resin in place of an aromatic epoxy resin that is easily deteriorated by light or heat (see, for example, Patent Documents 1, 2, and 3). ).

  On the other hand, an epoxy resin composition using such an alicyclic epoxy resin has a drawback that the obtained cured product has poor toughness and is liable to crack due to changes in conditions such as temperature. In order to solve this, as a method for toughening a cured product obtained from an epoxy resin composition, a technique using a modifier composed of various polymers is known. For example, a polyester resin is added to an epoxy resin composition. There has been proposed a method for improving toughness without impairing the transparency of a cured product by addition (see, for example, Patent Document 4).

However, since a polyester resin generally tends to be colored at the time of condensation, in the invention described in Patent Document 4, the cured product is markedly colored from yellow to brown as shown in the examples. For this reason, there has been a practical problem in applications that are required to be colorless and transparent, such as the LED sealing material.
JP 2000-196151 A JP 2003-012896 A JP 2003-221490 A JP 2004-131553 A

  The present invention has been made in view of the above problems, and provides an epoxy resin composition that gives a cured product that is less colored and has excellent crack resistance and transparency, a cured product thereof, and an optical semiconductor device. .

  As a result of intensive studies to solve the above-mentioned problems, the inventors have added and mixed a dendritic polymer as a modifier to the epoxy resin and the polyvalent carboxylic acid anhydride, thereby reducing coloring and resistance. It has been found that an epoxy resin composition giving a cured product having excellent cracking properties and transparency can be easily obtained, and the present invention has been completed.

The present invention relates to the following.
(1) An epoxy resin composition comprising an epoxy resin, a polyvalent carboxylic acid anhydride and a dendritic polymer.
(2) The epoxy resin composition according to item (1), wherein the polyvalent carboxylic acid anhydride is a compound represented by the following general formula (1).

（式中、Ｒ_１〜Ｒ_４は、それぞれ独立に、水素原子又は直鎖若しくは分岐状の炭素数１〜４のアルキル基を表し、Ｒ_１〜Ｒ_４から選ばれる二つが結合して環を形成してもよい。）

(Wherein R _{1 to} R ₄ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and two selected from R _{1 to} R ₄ are bonded to form a ring. It may be formed.)

(3) The epoxy resin composition according to item (1) or item (2), wherein the dendritic polymer is polyester.
(4) The epoxy resin composition according to any one of items (1) to (3), wherein the dendritic polymer is contained in an amount of 1 to 60 parts by weight with respect to 100 parts by weight of the epoxy resin.
(5) A cured product obtained by curing the epoxy resin composition according to any one of items (1) to (4).
(6) An optical semiconductor device in which an optical semiconductor element is sealed with a cured product according to item (5).

  ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition which gives the hardened | cured material which has little coloring, and is excellent in crack resistance and transparency, its hardened | cured material, and an optical semiconductor device can be obtained easily.

Hereinafter, the present invention will be described in detail.
The polycarboxylic acid anhydride used in the present invention is not particularly limited. For example, succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, itaconic anhydride Examples include acid, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, and the like. Two or more of these may be used in combination.

  In order for the cured product obtained by the present invention to exhibit the effects of less coloring and excellent crack resistance and transparency, the polyvalent carboxylic acid anhydride is represented by the general formula (1). A compound is preferred.

  Examples of such compounds include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylendomethylenehexahydrophthalic anhydride, and the like. Two or more of these may be used in combination.

  The amount of polyvalent carboxylic acid anhydride used is preferably such that the acid anhydride group is 0.8-1 equivalent to 1 equivalent of epoxy group in the epoxy resin, and is 0.9-1 equivalent. It is more preferable to blend so that. If the acid anhydride group is less than 0.8 equivalent, curing may be insufficient, and the mechanical properties of the cured product may be significantly reduced. Also, when the acid anhydride group exceeds 1 equivalent, the mechanical properties of the cured product may be similarly reduced.

  The dendritic polymer used in the present invention is not particularly limited, but in order to exhibit the effects of the cured product obtained by the present invention, which is less colored and excellent in crack resistance and transparency, more remarkably. Is preferably polyester. Further, it is more preferable that the polyester has 1 to 50 generations, preferably 1 to 10 generations of at least one dihydroxymonocarboxylic acid added to a nucleus having at least one reactive epoxide group or hydroxyl group.

  Preferred nuclei include alcohols such as neopentyl glycol, trimethylolpropane, pentaerythritol, 2-butyl-2-ethyl-1,3-propanediol, epoxides such as glycidyl esters of monocarboxylic acids, glycidyl ethers of monoalcohols, etc. And the like.

  Examples of the dihydroxy monocarboxylic acid include 2,2-bis (hydroxymethyl) propionic acid and 2,2-bis (hydroxymethyl) butanoic acid. There is no restriction | limiting in particular in the manufacturing method of the dendritic polymer used for this invention, A well-known method is applicable.

  In this invention, it is preferable that 1-60 weight part is contained with respect to 100 weight part of epoxy resins, and it is more preferable that dendritic polymer is contained 30-50 weight part. When the content of the dendritic polymer is less than 1 part by weight, the toughness of the obtained cured product is not sufficient, and the crack resistance may be lowered. On the other hand, if the content of the dendritic polymer exceeds 60 parts by weight, the glass transition temperature of the resulting cured product may be remarkably lowered, which is not preferable for practical use.

  Although there is no restriction | limiting in particular in the epoxy resin used for this invention, An alicyclic epoxy resin is preferable from the surface of light resistance and heat resistance. The alicyclic epoxy resin has an alicyclic skeleton and two or more epoxy groups in one molecule. For example, 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis ( 3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene dioxide, hydrogenated bisphenol A diglycidyl ether, and the like. Two or more of these may be used in combination.

  Further, an epoxy resin other than the alicyclic epoxy resin can also be used depending on the purpose. Examples of such epoxy resins include bisphenol type epoxy resins obtained by reaction of bisphenols such as bisphenol A and bisphenol S with epichlorohydrin, and phenol novolak types obtained by reaction of phenol novolac and epichlorohydrin. Examples thereof include an epoxy resin, a glycidyl ester type epoxy resin obtained by a reaction between a polyvalent carboxylic acid and epichlorohydrin. Two or more of these may be used in combination.

  The amount of the epoxy resin other than these alicyclic epoxy resins is preferably 0 to 80 parts by weight, more preferably 0 to 20 parts by weight with respect to 100 parts by weight of the alicyclic epoxy resin. When the usage-amount of epoxy resins other than an alicyclic epoxy resin exceeds 80 weight part, there exists a possibility that the light resistance and heat resistance of hardened | cured material may fall.

  In the present invention, the target epoxy resin composition can be obtained by mixing an epoxy resin, a polyvalent carboxylic acid anhydride and a dendritic polymer, but the production method is not particularly limited, and is publicly known. The method can be applied.

  In the epoxy resin composition of the present invention, a curing accelerator can be appropriately added depending on the purpose. Examples of the curing accelerator include imidazoles such as 2-ethyl-4-methylimidazole and 1-methylimidazole, tertiary amines such as benzyldimethylamine and N, N-dimethylaniline, tetramethylammonium chloride, and benzyltriethylammonium chloride. Quaternary ammonium salts such as tetra-n-butylphosphonium o, o-diethyl phosphorodithionate, phosphonium salts such as tetrabutylphosphonium benzotriazolate, metal salts such as zinc octylate and zinc stearate, zinc acetylacetone, Examples thereof include metal complexes such as benzoylacetone zinc.

  The blending amount of the curing accelerator in the epoxy resin composition is preferably 0.01 to 8% by weight, and more preferably 0.1 to 5% by weight. If the blending amount of the curing accelerator is less than 0.01% by weight, a sufficient effect may not be obtained. Moreover, when the compounding quantity of a hardening accelerator exceeds 8 weight%, there exists a possibility that the hardened | cured material obtained may be colored or heat resistance may fall.

  Various additives can be further added to the epoxy resin composition according to the present invention depending on the purpose within a range that does not impair the properties of the resulting cured product. Examples of the additive include a flexibilizer, a heat stabilizer, an ultraviolet absorber, a flame retardant, an antistatic agent, an antifoaming agent, a thixotropic agent, and a release agent. Furthermore, for example, an antioxidant for further improving the light resistance and heat resistance of the cured product, a chain transfer agent for controlling the polymerization reaction during curing, and improving the mechanical properties, adhesiveness, and handleability of the cured product. Fillers, plasticizers, stress reducing agents, coupling agents, dyes, light scattering agents and the like.

  By curing the epoxy resin composition in the present invention with heat, a cured product with little coloration and excellent crack resistance and transparency can be obtained. There is no restriction | limiting in particular in the manufacturing method of hardened | cured material, A well-known method is applicable. Although the temperature and time of heat-curing are not specifically limited, 90-180 degreeC and 1-12 hours are preferable. The LED light-emitting element or the like can be sealed by providing the epoxy resin composition on the surface of the LED light-emitting element or the like by a method such as coating, potting, or impregnation, followed by heat curing.

  The optical semiconductor device of the present invention is an optical semiconductor element such as an LED light emitting element or a photodiode element sealed with the above cured product, has little coloring, is excellent in crack resistance and transparency, and further has light resistance and It also has excellent heat resistance.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by these examples.
Example 1
3 'as an epoxy resin with respect to 40 parts by weight of a dendritic polymer (BOLTORN P-500: manufactured by Perstorp) obtained by adding 2,2-bis (hydroxymethyl) propionic acid with trimethylolpropane as a core , 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celoxide 2021P: manufactured by Daicel Chemical Industries, Ltd./epoxy equivalent 138 (g / eq)), tetra-n-butylphosphonium as a curing accelerator 1 part by weight of o, o-diethyl phosphorodithionate (Hishicolin PX-4ET: manufactured by Nippon Chemical Industry Co., Ltd.), 9,10-dihydro-9-phospha-10-oxaphenanthrene-9-oxide (as a stabilizer) HCA: manufactured by Sanko Chemical Co., Ltd.) The mixture was heated and stirred to dissolve uniformly.

  Furthermore, 116 parts by weight of 4-methylhexahydrophthalic anhydride (HN-7000: manufactured by Hitachi Chemical Co., Ltd./acid anhydride equivalent 168 (g / eq)) as polyvalent carboxylic acid anhydride was heated to 80 ° C. The resultant was added with stirring and dissolved until uniform to obtain an epoxy resin composition (I).

  Next, after sufficiently degassing the epoxy resin composition (I) under reduced pressure, the metal clip was gently poured into a metal petri dish placed at the center, heated at 120 ° C. for 1 hour, and then further 150 Heated at 4 ° C. for 4 hours to obtain a cured product (I).

(Comparative Example 1)
100 parts by weight of 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celoxide 2021P: manufactured by Daicel Chemical Industries, Ltd./epoxy equivalent 138 (g / eq)), tetra-n- as a curing accelerator 1 part by weight of butylphosphonium o, o-diethyl phosphorodithionate (Hishicolin PX-4ET: manufactured by Nippon Chemical Industry Co., Ltd.), 9,10-dihydro-9-phospha-10-oxaphenanthrene-9- as a stabilizer 1 part by weight of oxide (HCA: manufactured by Sanko Chemical Co., Ltd.) was added, heated to 80 ° C., stirred and dissolved uniformly.

Furthermore, 116 parts by weight of 4-methylhexahydrophthalic anhydride (HN-7000: manufactured by Hitachi Chemical Co., Ltd./acid anhydride equivalent 168 (g / eq)) was heated to 80 ° C. and added with stirring. It was made to melt | dissolve until it became epoxy resin composition (II).
Thereafter, a cured product (II) was obtained in the same manner as in Example 1.

The appearance and cracks of the cured products (I) and (II) obtained in Example 1 and Comparative Example 1 were evaluated, and the results are shown in Table 1. The characteristic evaluation method in Table 1 is as follows.
Appearance: Judged by visual inspection.
Crack: The cured product was allowed to stand at −30 ° C. for 20 hours and then allowed to stand at room temperature (25 ° C.) for 10 hours, and the presence or absence of cracks was visually confirmed.
○: No crack
×: Crack present

（配合単位は、重量部）

(The blending unit is parts by weight)

As shown in Table 1, it was found that the cured product obtained in Example 1 was colorless and transparent without cracks. In contrast, the cured product of Comparative Example 1 was cracked and colored yellow. According to the present invention, it was possible to obtain an epoxy resin composition and a cured product thereof that give a cured product with little coloration and excellent crack resistance and transparency.

Claims (5)

An epoxy resin, a polyvalent carboxylic acid anhydride represented by the following general formula (1), and a polyester in which at least one dihydroxymonocarboxylic acid is added to a nucleus having at least one reactive epoxide group or hydroxyl group An epoxy resin composition comprising a dendritic polymer.

(Wherein R _{1 to} R ₄ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and two selected from R _{1 to} R ₄ are bonded to form a ring. It may be formed.) At least one dihydroxy monocarboxylic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) according to claim 1 Symbol placement of the epoxy resin is one or more compounds selected from butanoic acid Composition. The epoxy resin composition according to claim 1 or 2 , wherein the dendritic polymer is contained in an amount of 1 to 60 parts by weight based on 100 parts by weight of the epoxy resin. Hardened | cured material formed by hardening | curing the epoxy resin composition in any one of Claims 1-3 . An optical semiconductor device comprising an optical semiconductor element sealed with the cured product according to claim 4 .