JP2712876B2 - Transparent epoxy resin composition for transfer mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition capable of obtaining a molded article having excellent transparency and heat resistance, for example, a transparent epoxy resin composition for a transfer mold useful for encapsulating a light emitting element, a light receiving element and the like. It is about things.

[0002]

2. Description of the Related Art Conventionally, epoxy resins are known as resins having excellent electrical properties, moisture resistance, heat resistance, and the like. Those using an amine-based curing agent and an acid anhydride-based curing agent as curing agents have been widely used. I have. Among these, in applications where good light transmittance is required in addition to the above characteristics, for example, as a sealing material for a light emitting element, a light receiving element, etc., a composition using an acid anhydride curing agent is used. .

The following are well known as sealing materials using this kind of curing agent. A liquid epoxy resin composition for casting, comprising a liquid epoxy resin at room temperature, an acid anhydride curing agent and a curing catalyst as main components. A solid transparent epoxy resin composition for transfer molding, containing a solid epoxy resin, an acid anhydride curing agent and a curing catalyst at room temperature as main components.

[0004]

However, since a relatively low molecular weight epoxy resin is used as a sealing material, a molded article having a high crosslink density can be obtained, but the impact resistance,
Due to poor adhesion to the element and cast molding, there were problems in workability and mass productivity. On the other hand, as the sealing material, it is necessary to select a relatively high molecular weight epoxy resin in order to enable transfer molding, and there is a problem in heat resistance of the molded product. Further, transfer molded articles are generally molded at a high temperature of 150 ° C. or higher, and thus have a problem that they are inferior in transparency, heat discoloration resistance, and optical uniformity as compared with cast molded articles.

[0005] Further, when a solid-state imaging device or the like is resin-sealed using the transfer molding resin composition in a state where foreign matters having a size of, for example, 5 μm or more are mixed in the resin composition,
The foreign matter appears as black spots in the obtained image. From the material side, the main cause of the contamination is considered to be the base epoxy resin and hardener.However, the conventional epoxy resin composition for transfer molding uses solid epoxy resin and hardener at room temperature. Therefore, it is impossible to remove the above-mentioned foreign substances such as dusts since they are kneaded at a temperature not higher than the melting point of.

An object of the present invention is to provide excellent heat resistance and transparency,
Another object of the present invention is to provide a transparent epoxy resin composition for transfer molding in which foreign matter such as dust is not mixed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the present invention provides a bisphenol-type epoxy resin, an alicyclic epoxy resin and an iodine value of 0.5 or less which are solid at room temperature. A transfer mold, characterized in that a composition obtained by heating and dissolving a resin composition containing an alicyclic acid anhydride curing agent and uniformly mixing the same contains an organic phosphorus compound represented by the following general formula [1]: The present invention provides a transparent epoxy resin composition for use.

Embedded image That is, since the epoxy resin and the acid anhydride, which are the main components of the reaction, are mixed in a liquefied state, the dispersion at the molecular level becomes possible. Further, since the viscosity of the mixed solution of the epoxy resin and the acid anhydride is several poise to several tens poise, foreign substances such as dust which cannot be removed conventionally can be easily removed by filtering this mixed solution. It is possible to

The bisphenol type epoxy resin has a melting point of 60 to 130 ° C., and preferably has a colorless or pale yellow transparent color when liquefied. If the melting point is lower than 60 ° C., burrs are likely to occur during molding, while if it exceeds 130 ° C., unfilling tends to occur during molding. Examples of such a resin include a bisphenol A epoxy resin, a bisphenol F epoxy resin, and a hydrogenated bisphenol A epoxy resin.

The alicyclic epoxy resin has a gelation time at 150 ° C. (measured with a JSR type curameter manufactured by Imanaka Kikai Kogyo Co., Ltd.) when an acid anhydride curing agent is used.
It is preferably 0 seconds or more. When an alicyclic epoxy resin having a gelling time of less than 60 seconds is used, the mixture is heated and dissolved at a temperature equal to or higher than the melting point of the epoxy resin and the curing agent together with the bisphenol-type epoxy resin and the acid anhydride curing agent, and uniformly mixed. This is because a microgel is easily generated at that time. Examples of such alicyclic epoxy resins include E
RL-4206 (liquid), ERL-4221 (liquid),
ERL-4234 (liquid), ERL-4299 (liquid)
(Manufactured by Union Carbide Co., Ltd.), CY-175 (liquid), CY-177 (liquid), CY-179 (liquid),
CY-184 (liquid), CY-192 (liquid) (all manufactured by Ciba-Geigy), EHPE-3150 (solid), celloxide 2021 (liquid), Eporide GT-300
(Liquid), Eporide GT-400 (Liquid) (all manufactured by Daicel Chemical Co., Ltd.), DCDE-200 (Solid) (Sanyo Kokusaku Pulp), and the like.

The mixing ratio of the bisphenol type epoxy resin to the alicyclic epoxy resin is 90:10 to 50:50.
(% By weight), and when the amount of bisphenol-type epoxy resin is large, the impact resistance and adhesion are improved,
Heat resistance and transparency are greatly reduced. When the amount of the alicyclic epoxy resin is large, heat resistance, transparency, and optical uniformity are improved, but the mechanical strength of the molded product is significantly reduced.

An acid anhydride as an epoxy resin curing agent is
An alicyclic acid anhydride having an iodine value of 0.5 or less is used. This is because when an alicyclic acid anhydride having an iodine value exceeding 0.5 is used, although the transparency at the time of initial curing is excellent, the color is significantly changed in an after-cure or long-term reliability test. In the present invention, hexahydrophthalic anhydride and / or methylhexadrophthalic anhydride having an iodine value of 0.5 or less are used. These acid anhydrides exhibit excellent weather resistance and discoloration stability.

The equivalent ratio of the epoxy resin to the acid anhydride curing agent is preferably from 0.85 to 1.1. If the equivalent ratio is less than 0.85, the heat resistance and the transparency are lowered. On the other hand, when the equivalent ratio exceeds 1.1, the water absorption increases and the moisture resistance decreases.

Further, the epoxy resin composition of the present invention preferably contains a curing accelerator for the purpose of accelerating the curing reaction between the epoxy resin and the acid anhydride. The curing accelerator is
It is not particularly limited and may be a known one, such as imidazoles and D
BU and its salts, tertiary amines, ammonium salts, phosphonium salts and the like are exemplified, and the amount of addition may be 0.1 to 5% by weight based on the total amount of the epoxy resin and the curing agent.

In the present invention, it is essential that the epoxy resin composition contains an organic phosphorus compound represented by the following general formula [1].

Embedded image (However, in the general formula [1], R _{1 to} R ₈ are a hydrogen atom, a halogen atom, or a monovalent aliphatic group or aromatic group having 1 to 10 carbon atoms, and R _{1 to} R ₈ are the same or different. May be.)

Specific examples include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The amount of the organic phosphorus compound to be added is 0.1 to the total amount of the epoxy resin, the curing agent and the curing accelerator.
It is preferable that the content be 1 to 10% by weight. When the amount of the organic phosphorus compound is less than 0.1% by weight, the effect of preventing coloration does not appear. Conversely, when the amount exceeds 10% by weight, heat resistance,
Impact resistance decreases.

The resin composition of the present invention is characterized in that a bisphenol type epoxy resin, an alicyclic epoxy resin and an alicyclic acid anhydride curing agent are mixed by heating and melting,
Other curing accelerators and organic phosphorus compounds do not necessarily need to be dissolved and mixed, and may be separately mixed after dissolving and mixing the epoxy resin and the curing agent. In the transfer molding epoxy resin composition of the present invention, a coloring agent, a release agent, an antioxidant, an ultraviolet absorber, if necessary, in addition to the above components,
Conventionally known additives such as a visible light absorber and a filler are used. Examples of the antioxidant include conventionally known compounds such as a phenol compound, a phosphite compound, and an organic sulfur compound.

[0017]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the physical property in an example showed the measured value by the following method. (1) Light transmittance Using a spectrophotometer (Hitachi U-2000 type), thickness 2
The light transmittance at 400 nm was measured for a mm sample. (2) Glass transition temperature TMA (PTC-10A, manufactured by Rigaku Corp.) was used for a sample having a diameter of 4 mm and a length of 20 mm.

Example 1 Bisphenol A type epoxy resin (Epomic R366, manufactured by Mitsui Petrochemical Co., Ltd., epoxy equivalent: 1020, melting point: 115 ° C.) 75 parts by weight alicyclic epoxy resin (Eporide GT-manufactured by Daicel Chemical Industries, Ltd.) 33, 25 parts by weight Hexahydrophthalic anhydride (Rikashid HH-A manufactured by Shin Nippon Rika Co., Ltd., acid anhydride equivalent 154, iodine value 0.2, melting point 34 ° C.) 33 parts by weight The mixture was heated and melted at ℃, uniformly mixed, and cooled to room temperature to obtain a primary resin composition. The following compound was blended with this resin composition, and using an extruder, a barrel temperature of 70 ° C.
Kneading was performed under the conditions of a screw rotation speed of 200 rpm. A secondary resin composition was obtained. Organophosphorus compound (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) 3 parts by weight 2-ethyl-4-methylimidazole 1 part by weight The secondary resin composition was molded at a molding temperature of 150 parts by weight. Transfer molding was performed at 4 ° C. (molding time: 4 minutes), followed by curing at 150 ° C. for 3 hours to obtain a cured resin.

Examples 2 to 5 Resin compositions were prepared in the same manner as in Example 1 according to the composition shown in Table 1, and then cured resin products were obtained.

Comparative Examples 1 to 5 Resin compositions were prepared in the same manner as in Example 1 according to the composition shown in Table 1, and then cured resin products were obtained. In addition, Examples 1 to
Table 1 also shows the measurement results of the physical properties of Comparative Example 1 and Comparative Examples 1 to 5. The glass transition temperature indicates a measured value after curing at 150 ° C. for 3 hours, and the light transmittance indicates a measured value after curing at 150 ° C. for 3 hours and a measured value after a heat deterioration test (150 ° C., 50 hours). Was.

[0021]

[Table 1]

In Table 1, AER667: bisphenol A type epoxy resin manufactured by Asahi Kasei Corporation, epoxy equivalent 2000, melting point 129 ° C. Suntote ST-510
0: hydrogenated bisphenol A type epoxy resin manufactured by Toto Kasei Co., Ltd., epoxy equivalent 950, melting point 100 ° C CY-17
5: Alicyclic epoxy resin manufactured by Ciba-Geigy Co., Ltd., epoxy equivalent 160ERL-4221: Alicyclic epoxy resin manufactured by Union Carbide, epoxy equivalent 137

[0023]

As is clear from the results shown in Table 1, according to the present invention, a transparent epoxy resin composition for transfer molding having excellent heat resistance and light transmittance can be obtained.

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H01L 23/31 (56) References JP-A-2-170820 (JP, A) JP-A-63- 83701 (JP, A) JP-A-60-14088 (JP, A)

Claims (3)

(57) [Claims] 1. A bisphenol-type epoxy resin which is solid at ordinary temperature, an alicyclic epoxy resin having a gel time at 150 ° C. of 60 seconds or more and an alicyclic acid anhydride curing agent having an iodine value of 0.5 or less are heated and dissolved. A transparent epoxy resin composition for transfer molding, characterized in that an organic phosphorus compound represented by the following general formula [1] is blended into a composition obtained by mixing uniformly. Embedded image (However, in the general formula [1], R1 to R8 are a hydrogen atom, a halogen atom, or a monovalent aliphatic or aromatic group having 1 to 10 carbon atoms, and R1 to R8 may be the same or different. ) 2. A bisphenol type epoxy resin having a melting point of 6
The transparent epoxy resin composition for transfer molding according to claim 1, which is an epoxy resin at 0 to 130C. 3. The mixing ratio (weight ratio) of the bisphenol type epoxy resin to the alicyclic epoxy resin is 90:10 to 5:
The transparent epoxy resin composition for transfer molding according to claim 1 or 2, wherein the ratio of the acid anhydride curing agent to the epoxy resin is from 0.85 to 1.1, and the equivalent ratio of the acid anhydride curing agent to the epoxy resin is from 0.85 to 1.1.