JPH05194716A - Liquid epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which is rapidly curable at low temperature, transparent, noncorrosive to metal, and excellent in resistance to PCT. CONSTITUTION:The title composition contains a curing agent comprising an acid anhydride and a cure accelerator comprising tetrabutylammonium octoate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin which is used in the optical field such as an optical lens, a prism and a sealing material for an optical semiconductor element and which has excellent colorless and transparent properties.

[0002]

2. Description of the Related Art Epoxy resin compositions conventionally used for optical applications, especially optical semiconductor elements (hereinafter abbreviated as LEDs)
, An epoxy resin composition using an acid anhydride curing agent is known, and a tertiary amine, an imidazole compound, an organic metal salt, or the like is used as a curing accelerator. However, when these curing accelerators are used, yellowing occurs due to a rapid reaction at 120 ° C. or higher. Therefore, a color preventive agent is added to prevent this, but when the addition amount is 3% or more,
The PCT resistance (121 ° C) causes a drastic change.

Further, as described in Japanese Patent Application Laid-Open No. 2-169619, when an onium salt is used as a curing accelerator, it has excellent transparency and can reduce stress. But,
Generally known onium salts have high hygroscopicity,
It is difficult to handle and causes curing failure. Moreover, because of the presence of water, hydrochloric acid and bromic acid are generated, the metal is attacked,
Especially, there is a drawback that the lead frame of the LED is contaminated.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a liquid epoxy resin composition useful for optical applications, which has a low-temperature fast-curing property, is transparent, has no metal corrosion, and is excellent in PCT resistance. It's about to get.

[0005]

The present invention is a liquid epoxy resin composition containing an acid anhydride as a curing agent and tetrabutylammonium octate as a curing accelerator.

Examples of the epoxy resin used in the present invention include a bisphenol type epoxy resin, an alicyclic epoxy resin, a novolac type epoxy resin, a saturated aliphatic or unsaturated aliphatic epoxy resin and the like, and they may be used alone or in a mixture. It doesn't matter. Although it may be a liquid or a solid, it may be a liquid when mixed with a curing agent. Since it is used for LED, it is preferable that it is less colored, and further, as a hue, Gardner 1
The following are desirable:

The acid anhydride curing agent used in the present invention includes phthalic anhydride, hexahydrophthalic anhydride,
Acid anhydrides such as tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, maleic anhydride, succinic anhydride, dodecynylsuccinic anhydride, dichlorosuccinic anhydride, methylnadic acid anhydride, pyromellitic anhydride, chlorendic acid anhydride, and benzophenonetetracarboxylic acid anhydride Things can be mentioned.

The curing accelerator used in the present invention is
It is a special onium salt in liquid form, which is a unique one different from the ones used conventionally in the industry.

Generally, such substances that have been industrially flown in the past include, for example, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium chromide, benzyltriteethylammonium chromide, tetra There are onium salts such as butylammonium iodide, tetrabutylphosphonium bromide and tetraphenylphosphonium bromide.

Most of the conventionally used onium salts are onium halides and are solid, so that they are not easily dissolved when they are made into a liquid composition, and further, they have high hygroscopicity and are in air. When exposed to water, it became an aqueous solution and had the drawback that it dissociates as an ionic substance and oxidizes and corrodes the metal. In addition, if a substance that has absorbed moisture is used as the curing agent, curing failure will occur. On the other hand, when using an onium halide dissolved in a curing agent, there is a drawback that when exposed to air, it is ionically dissociated under the influence of moisture in the air and oxidizes and corrodes the metal. It was

When the curing accelerator of the present invention is used, the above-mentioned metal corrosion does not occur and it is liquid, so that it is easy to prepare a liquid composition. Even if the curing accelerator of the present invention dissociates as an ionic substance in the presence of water, the pH of the aqueous solution shows 7 or more because of the strong basicity of onium, and thus does not cause oxidative corrosion of metals. is there. Furthermore, since it is liquefied, its hygroscopicity is reduced and its solubility in an acid anhydride is facilitated, which is preferable. Furthermore, the compound is stable.

The addition amount of the curing accelerator of the present invention is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin. If the amount added exceeds 10 parts by weight, the effect of preventing foaming and coloration of the cured product is lost, and if it is less than 0.1 part by weight, a sufficient effect of promoting curing cannot be obtained.

The raw material components used in the liquid epoxy resin composition of the present invention include dyes, if necessary.
Additives such as modifiers, anti-coloring agents, anti-aging agents, release agents, and reactive or non-reactive diluents can be added.

[0014]

The present invention will be described below with reference to Examples and Comparative Examples.

(Example 1) 75 parts of bisphenol A type epoxy resin (epoxy equivalent of about 190) (parts by weight, the same applies hereinafter), alicyclic epoxy resin (ERC4221 manufactured by UCC) 2
A liquid epoxy resin composition was obtained by mixing 5 parts, 98 parts of methylhexahydrophthalic anhydride, 2 parts of tetrabutylammonium octate, and 2 parts of other additives such as an anti-coloring agent and an antifoaming agent. The characteristics of this product are shown in Table 1. Table 2 shows the results of the metal corrosion test of the curing accelerator.

(Comparative Examples 1 to 6) In Example 1, the properties and the results of the metal corrosion test were conducted in the same manner as in Example 1 except that tetrabutylammonium octate as a curing accelerator was used instead of tetrabutylammonium octate. 2 shows. As shown in the table, the one using the curing accelerator of the present invention has an excellent appearance and PC resistance.
The T property was also excellent, and metal corrosion could be prevented.

[0017]

[Table 1]

As the curing accelerator, A: tetrabutylammonium octate B: tetrabutylammonium bromide C: tetrabutylphosphonium bromide D: tetrabutylammonium chloride E: benzyltriethylammonium chloride F: benzyltriphenylphosphonium chloride G : 2-ethyl-4-methylimidazole was used respectively. The PCT conditions were 121 ° C and 2.3 atm, and the appearance was markedly changed compared to the initial stage.
Those that hardly changed were marked with "○". Regarding the appearance after curing, the one colored in yellow was designated as "x".

[0019]

[Table 2]

As the curing accelerator, the same ones as in Table 1 were used for AF. G was insoluble in water and could not be measured. (Test 1) Each quaternary salt was dissolved in water to make a 5% aqueous solution, and a tin plate (5 mm x 30 mm) partially sanded (# 200) was used as a test piece for immersion in a 5% aqueous solution. Then, after 24 hours, observe whether corrosion occurs,
Those with corrosion were marked with "x", and those without corrosion were marked with "○". (Test 2) Each quaternary salt was dissolved in an acid anhydride (hexahydrophthalic anhydride) to make a 5% solution, which was immersed in a 5% solution using the same test piece, and 24 hours later. Whether corrosion occurred or not was observed and evaluated in the same manner. (Test 3) Each quaternary salt was dissolved in an acid anhydride (hexahydrophthalic anhydride) to make a 5% solution, and a 5% solution was dropped using the same test piece, and after 12 hours corrosion Was observed and evaluated in the same manner.

[0021]

According to the present invention, it is possible to obtain a liquid epoxy resin composition which is fast-curing at low temperature, has transparency, has no metal corrosiveness, and has excellent PCT resistance. INDUSTRIAL APPLICABILITY The resin composition of the present invention has excellent properties in the optical field, particularly for encapsulating optical semiconductors, and can be suitably used.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 19, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

Examples of the epoxy resin used in the present invention include a bisphenol type epoxy resin, an alicyclic epoxy resin, a novolac type epoxy resin, a saturated aliphatic or unsaturated aliphatic epoxy resin and the like, which may be used alone or in a mixture. It doesn't matter. Although it may be a liquid or a solid, it may be a liquid when mixed with a curing agent. Since it is used for LED, it is preferable that it is less colored, and further, as a hue, Gardner 1
The following are desirable: The epoxy resin has a halogen content of ionic impurities of 200 ppm or less, preferably 100 ppm or less, which is usually used for semiconductor encapsulation.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Most of the conventionally used onium salts are onium halides and are solid, so that it is not easy to dissolve them when they are made into a liquid composition, and furthermore, they have a high hygroscopic property and they are in the air. When exposed to water, it became an aqueous solution and had the drawback that it dissociates as an ionic substance and oxidizes and corrodes the metal. In addition, when a substance that has absorbed moisture is used as a curing agent, poor curing occurs. On the other hand, when using an onium halide dissolved in a curing agent, there is a drawback that when exposed to the air, it is ionically dissociated under the influence of moisture in the air and oxidizes and corrodes the metal. It was Conventionally used onium salts are difficult to remove ionic impurities, and usually contain 1000 ppm. The curing accelerator of the present invention has been made possible to eliminate the defects by performing a special treatment to reduce the halogen as an ionic impurity to 100 ppm or less. In addition, as for the amount of ionic impurities, when a large amount of halogen is contained, Ag of the lead frame is corroded during the temperature / humidity treatment, adhesion failure or corrosion of Al contained in the compound semiconductor is promoted, and luminance deterioration is large. Become. The content of halogen is 300 ppm as a whole, preferably 200 ppm or less.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

Example 1 Bisphenol A type epoxy resin (epoxy equivalent of about 190: chlorine content 100 ppm) 75 parts (parts by weight, the same applies hereinafter), alicyclic epoxy resin (UCL ERL4221) 25 parts, methyl hexa A liquid epoxy resin composition was obtained by mixing 98 parts of hydrophthalic anhydride, 2 parts of tetrabutylammonium octate (chlorine content 10 ppm), and 2 parts of other additives such as a coloring inhibitor and an antifoaming agent. The characteristics of this product are shown in Table 1. Table 2 shows the results of the metal corrosion test of the curing accelerator. In addition, the light emitting display element (Ga
The residual brightness rate when applied to AlAs) was 92%.
On the other hand, when tetrabutylammonium octate with a chlorine content of 500 ppm is used for comparison, the residual brightness ratio is
It was 76%.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

As the curing accelerator, A: tetrabutylammonium octate B: tetrabutylammonium bromide C: tetrabutylphosphonium bromide D: tetrabutylammonium chloride E: benzyltriethylammonium chloride F: benzyltriphenylphosphonium chloride G : 2-ethyl-4-methylimidazole was used respectively. The PCT conditions were 121 ° C and 2.3 atm, and the appearance was markedly changed compared to the initial stage.
Those that hardly changed were marked with "○". Regarding the appearance after curing, the one colored in yellow was designated as "x". The chlorine measurement method is as follows: heating in the presence of 0.1N KOH-methanol solution at 80 ° C. for 15 minutes, the amount of KCl produced is AgNO.
Potentiometric titration was performed at ₃ to determine the content of hydrolyzable Cl. Brightness residual rate is 20% after processing PCT (121 ° C, 2.3 atm)
After further dipping the solder at 260 ℃ for 10 seconds, 85 ℃, 85%
The luminance was measured after passing 450 hours under the condition of RH and passing a current of 15 mA.

Claims (1)

[Claims] 1. A liquid epoxy resin composition containing an acid anhydride as a curing agent and tetrabutylammonium octate as a curing accelerator.