JPS59174618A - Epoxy resin composition for photo-semiconductor sealant having excellent moisture resistance - Google Patents

Abstract

PURPOSE:To provide the titled epoxy resin composition having excellent moisture resistance and transparency, by using a bisphenol A novolak resin and optionally an acid anhydride as the hardener. CONSTITUTION:The objective composition contains (A) an epoxy resin and (B) a bisphenol A novolak resin as a hardener at a ratio of preferably 1:(0.8-1.2) in terms of the epoxy group to the phenolic hydroxyl group, or contains (A') an epoxy resin and (B') the above novlak resin and an acid anhydride (e.g. phthalic anhydride) at a ratio of 1:(0.5-2) in terms of the epoxy group to the sum of the phenolic hydroxyl group and the acid anhydride group in the hardener. The amount of the acid anhydride is preferably <=30pts.wt. per 100pts.wt. of the novolak resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel and useful epoxy resin composition for encapsulating optical semiconductors, and more particularly, to a moisture-resistant epoxy resin composition containing a specific resin as a curing agent for the epoxy resin. excellent,
Furthermore, the composition of the present invention relates to a resin composition that is highly transparent and useful for encapsulating light emitting diodes, that is, light emitting elements or related components thereof, and light receiving elements or electronic components. It has the characteristics of being able to fully withstand severe moisture resistance tests, and at the same time, not discoloring or reducing transparency in any way.

Conventionally, this type of epoxy resin composition for encapsulating light emitting diodes has been composed of a bisphenol A-based epoxy resin as a main ingredient, an acid anhydride as a curing agent, and a curing accelerator. However, the reason why such a composition is used is mainly due to the required property of transparency required of a material for sealing a light emitting diode.

As is well known, the reason why a curing accelerator is used in the above-mentioned resin composition is that when an acid anhydride curing agent is used, the curing rate generally decreases.

Incidentally, although epoxy resin-acid anhydride-based products generally have excellent transparency of the cured product, they have problems with moisture resistance of the cured product, and are difficult to perform in the pressure Kutzker test (p.
In a test in which the cured product was left in water vapor at 121° C. and 2 atm pressure, the cured product became cloudy and had a large water absorption rate.

On the other hand, curing agents for epoxy resins include amine compounds and phenolic novolak resins, but the reason why these curing agents have not been used in this type of resin composition for encapsulating light emitting diodes to date is because This is probably due to the disadvantage that epoxy resin compositions using these curing agents undergo significant discoloration during curing or during use after curing, especially when left at high temperatures.

However, as a result of intensive studies by the present inventors in order to obtain an epoxy resin composition for encapsulating optical semiconductors that eliminates all the various drawbacks of the conventional techniques as described above, the present inventors found that as a curing agent,
It was discovered that a system using a specific phenolic novolac resin called bisphenol-based novolac resin has excellent moisture resistance based on the pressure Kutzker test, and in addition, it does not discolor at all even when left under high temperatures. As a result, we have completed the present invention.・In other words, the present invention uses an epoxy resin and bisphenol A.
An epoxy resin for encapsulating optical semiconductors having particularly excellent moisture resistance and comprising a curing agent such as a novolac resin as an essential component, or an epoxy resin and a curing agent comprising the novolac resin and an acid anhydride as essential components. A composition is provided. .

Here, the epoxy resin may be any type of known and commonly used epoxy resin, but among them, bisphenol A-based epoxy resins, novolac-based epoxy resins, alicyclic epoxy resins, etc. are representative. These may be used alone, or two or more types may be used in combination. Among these, polyphenols, especially polyglycidyl ether type polyphenols of bisphenol A-based or novolac-based polyphenols, are the most suitable because they have excellent curability, adhesive properties, and physical properties of hard L materials. .

In addition, when the composition of the present invention is provided as a liquid, it is also possible to use a known and commonly used reactive diluent such as a relatively low viscosity monoepoxide compound or polyepoxide compound. If the material is provided as a flame retardant type, it may also be possible to use a halogenated polyepoxide.

Among the curing agents, bisphenol A-based novolak resin refers to a resin obtained by reacting bisphenol A and a formaldehyde supplying substance such as formaldehyde in the presence of an acidic catalyst, and some of them are It may be modified with various phenolic compounds such as phenol, cresol or xylenol, and as a cap for use of this novolac resin, the phenol hydroxide group in the novolac resin is added to each epoxy group in the epoxy resin. An appropriate ratio is 0.5 to 2.0, preferably 08 to 1.2.

On the other hand, among the above-mentioned curing agents, all acid anhydrides that are generally used as curing agents for epoxy resins can be used, but representative ones include phthalic anhydride, hexahydrocarbon phthalic anhydride,
Examples include methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, maleic anhydride, or trimellitic anhydride, and these may be used alone or in combination of two or more. Of course it's a good thing.

The amount of acid anhydride used is 50 parts by weight per 100 parts by weight of the bisphenol A novolac resin.
Suitably up to 30 parts by weight, preferably up to 30 parts by weight.

The composition of the present invention contains the above-mentioned epoxy resin and bisphenol A-based novolac resin, or epoxy resin, bisphenol A-based novolak resin, and acid anhydride as essential components, but additionally contains as necessary components. Depending on the situation, a curing accelerator may also be used in combination, and suitable curing accelerators include 6th class amines or imidazole compounds, among which representative examples include benzyl 2-dimethylamine and triethanolamine. ,2,4,
6-tris(dimethylaminomethyl)phenol or diazabicycloalkanes such as triethylenediamine, or 6-class amines such as diazabicycloalkenes such as 1,8-diazabicyclo(5,4,0)undecene-7; , 2-methylimidazole, 2-ethyl-4
- An imidazole compound such as methylimidazole or 1-benzyl-2-methylimidazole.

Of course, either one of these tertiary amines and imidazole compounds may be used, or both may be used in combination.

The appropriate amount of the curing accelerator used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the curing agent.

Furthermore, if necessary, the composition of the present invention may be blended with a discoloration inhibitor such as hindered phenols or organic sulfides, or may be blended with a carboxylic acid metal salt as part of a curing accelerator. Good too.

Furthermore, the composition of the present invention may contain a coloring agent such as a dye or a pigment, but in this case, the composition must have good dispersibility in the epoxy resin and be resistant to discoloration according to the heat resistance deterioration test. It is necessary that there be.

In addition, various additives such as conventionally known fillers, plasticizers, and light scattering agents such as calcium carbonate may be used, provided they do not adversely affect or reduce the effects of the present invention. There is no problem in using .

The epoxy resin composition of the present invention thus obtained can be used as a resin for sealing various semiconductors including light emitting diodes by a known sealing method, such as a potting method, dipping method or transfer method.

Thus, in the present invention, it is essential to use the above-mentioned bisphenol A-based novolac resin as a curing agent for the epoxy resin, but it is also possible to use conventionally known acid anhydrides as such a curing agent. The combination of an acid anhydride enhances the transparency of the composition of the present invention, making it even more advantageous, and the epoxy resin, which is the main component in the composition of the present invention, has excellent mechanical and electrical properties. In addition, it has good physical properties such as adhesiveness,
As mentioned above, it is extremely revolutionary that the composition of the present invention can be used to further improve transparency and prevent deterioration of moisture resistance, and the composition of the present invention can be used in a wider range of applications. Become something.

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, where all parts and percentages are based on weight unless otherwise specified.

Example 1 [Prior Fair KH-8870J [: Bisphenol A-based novolac m fat manufactured by Inu Nippon Ink Chemical Industry ■]
p = 105°C, hydroxyl equivalent = 120],
"Epicron 520J (epoxy diluent manufactured by the same company:
Epoxy equivalent = 220) was mixed with 30 parts of epoxy equivalent at 50° C. to obtain a melt. Hereinafter, this will be abbreviated as "dissolved material S-1."

Next, [Epicron 840J (bisphenol A type epoxy resin manufactured by the same company; epoxy equivalent = 180)
100 parts of molten material S-1, 80 parts of dissolved material S-1 and [2-ethyl-4
-Methylimidazole] were uniformly mixed to obtain an epoxy resin composition.

After that, this resin composition was poured into a predetermined mold, and 12
The mixture was left in a dryer at 0° C. for 15 hours to heat cure and obtain a colorless and transparent cast product.

Separately, the above epoxy resin composition was heated at 140°C.
When the film was heated and cured by being left in a dryer for 2 hours, there was no discoloration and the transparency was not impaired at all.

Example 2. 7”5io-7xy KH-888oJ [::iE
Bisphenol A-based novolak resin manufactured by Kagaku Kogyo ■: mp = 120°C, hydroxyl equivalent = 110°C)
Part oo and 60 parts of "Epicron 520" were mixed while heated to 50°C to obtain a melt (S-2).

Next, [Epicron 850J (liquid bisphenol A type epoxy resin manufactured by the same company; epoxy equivalent = 19
0), 60 copies of S-1, “Ebiku CI:/B
-10 parts of -650J (hexahydrophthalic anhydride manufactured by the same company: acid anhydride equivalent = 168), 1-U-CAT-8A
-102J (1,8-diazabicyclo(5,4,0) undecene-7 manufactured by Su7-7 Botto■ (hereinafter referred to as "
It is abbreviated as DBUJ. ) of 2-ethylhexanoate] and 1-U-CAT-8A-,5o
An epoxy resin composition was obtained by uniformly mixing 0.4 part of 6J (para-toluene sulfonate of DBU manufactured by Fiyl Kamisha).

Thereafter, a cast product was obtained in the same manner as in Example 1 except that this composition was used, and the heat discoloration resistance was also observed, and a colorless and transparent cast product was obtained.

Comparative Example 1 100 cities of "Epicron 840", 1 Ebicuron B-
A control epoxy resin composition was obtained by uniformly mixing 85 parts of ``650'' and 15 parts of [Curesol 2E4MZJ. When heated and cured under the conditions of 140'C x 2 hours, it was confirmed that there was a slight yellowing.

Example 6 [Epicron ID50J (solid bisphenol A type epoxy resin manufactured by the same company) was heated using a 90°C heated roll.
Epoxy equivalent = 450) 100 parts, 20 parts of Pryophen KH-887DJ, 1.0 part of octylate of triethylenediamine and 0.4 parts of calcium stearate.
A uniform solid epoxy resin composition was obtained by mixing the parts.

This composition was then placed in a mold at 180'C and heated from 6 to
After molding under pressure for 5 minutes, a colorless and transparent molded product was obtained.

Furthermore, this molded product was heated to 150'C for 6 hours,
It was confirmed that there was almost no discoloration.

Example 4 Using a 90°C heat roll, "Evicron 2050J (
Solid bisphenol A type epoxy resin manufactured by the same company: 100 parts of epoxy f-600), 15 parts of 1-Priorophen KH-888, DJ, 4.5 parts of tetrahydrophthalic anhydride, 1-U-CAT -8A-603J
(same product; DBU formate) and [
1.0 part of Curesol 2 MZJ (2-methyl-imidazole manufactured by the same company) was kneaded to obtain a uniform solid epoxy resin composition.

Next, a colorless and transparent molded product was obtained in the same manner as in Example 1, except for using this composition, and then heated and the degree of discoloration was observed, and it was found that there was almost no discoloration. was confirmed.

Comparative Example 2 [Same as Example 6 except that 100 parts of Evicron 105DJ, 40 parts of tetrahydrophthalic anhydride, 1.0 part of triethylenediamine octylate and 0.4 part of calcium stearate were used. A uniform solid control epoxy resin composition was obtained, and a colorless and transparent molded product was obtained in the same manner as in Example 3, except that this composition was used thereafter, and then the degree of discoloration due to heating was determined. When observed, it was confirmed that there was considerable yellowing.

Various tests as shown below were conducted on each of the molded products obtained in the following Examples and Comparative Examples.

1. Discoloration Each molded product was left at 130°C for 1000 hours and the degree of discoloration was observed.

The results showed that all of the molded products obtained from the compositions of the present invention showed almost no discoloration, but the control molded products obtained in Comparative Examples 1 and 2 all turned yellow. It was confirmed that it has changed.

2. Heat Resistance 2-1 Each molded product was placed in boiling water and left for 200 hours, then pulled out and observed for transparency.

The results showed that none of the molded products obtained from the composition of the present invention showed any cloudiness and no decrease in transparency, but the molded products obtained from the compositions of the present invention showed no decrease in transparency. It was confirmed that all of the products had significant white turbidity and a considerable decrease in transparency.

2-2 Perform a pressure Kutzker test on each molded product to measure its moisture absorption rate and evaluate its moisture resistance.

The results showed that the molded products obtained from the composition of the present invention all showed lower moisture resistance values than the control molded products obtained in Comparative Examples 1 and 2. It was also confirmed that the characteristics were excellent.

The moisture absorption data for each molded product is summarized in Table 1, and each value in the table represents the weight loss (% by weight) when left in water vapor under the conditions described above for 48 hours. It is expressed.

Table 1 Procedural amendment (voluntary) November 21, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Indication of the case 1982 Patent Order No. 48839 2. Name of the invention Optical semiconductor encapsulation with excellent moisture resistance Epoxy resin composition 3 for
Relationship with the case of the person making the amendment Patent applicant 3-35-58 Sakashita, Itabashi-ku, Tokyo 174 (28
8) Dainippon Ink & Chemicals Co., Ltd. Representative Yo Mura
Kuni Shigeru 4, Agent: Dainippon Ink & Chemicals Co., Ltd., 3-7-20 Nihonbashi, Chuo-ku, Tokyo 103 Phone number: Tokyo (03) 272-4511 (main representative) 6
, the content of the amendment is corrected to 1 "Reactive diluent".

(2) Description on page 17, line 10 "2. Heat resistance" r2. Corrected to "moisture resistance".

(3) Description on page 18, line 12 "Reduction" ``I'll correct it further.

that's all

Claims (1)

[Scope of Claims] ・t Contains an epoxy resin and a curing agent such as a bisphenol A 3°-based novolac resin as essential components, or comprises an epoxy resin, the above-mentioned novolak resin, and a curing agent such as an acid anhydride. An epoxy resin composition for encapsulating optical semiconductors having particularly excellent moisture resistance. λ The amount of the curing agent that is the bisphenol A-based novolac resin used is such that the ratio of the epoxy groups in the epoxy resin to the phenolic hydroxyl groups in the curing agent is 1:0.5 to 2.
2. The composition according to claim 1, wherein the composition is in a range of 0. 5. The amount of the bisphenol A-based novolak resin and acid anhydride curing agent used is such that the ratio of the epoxy group in the epoxy resin to the total of the phenolic hydroxyl group and acid anhydride group in the curing agent is 1:0. 5. The composition according to claim 1, wherein the molecular weight is in the range of 5 to 2.0.