JPS5830893B2 - Colorless transparent epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a colorless and transparent epoxy resin composition with excellent heat deterioration resistance.

More specifically, the present invention is a resin composition that has excellent colorless transparency and is suitable for optical applications such as optical lenses, prisms, and sealing of light emitting diodes. It has the characteristic that it does not cause any damage or decrease in transparency.

Conventionally, for such uses, tertiary amines or organic acid salts thereof are used to accelerate curing in thermosetting resin compositions mainly composed of mixtures of epoxy resins and organic polybasic acid curing agents. It is generally used as a tertiary amine, and it has been known that strongly basic and saturated alicyclic type amines such as diazabicycloalkenes are particularly effective as tertiary amines.

However, such compositions are desirably cured at 100° C. or lower; heating at 120° C. or higher tends to discolor them to yellow or yellowish brown, and they do not have sufficient heat deterioration resistance.

In order to improve this, discoloration inhibitors such as hindered phenols and organic phosphites are used in combination, or a very small amount of blue to purple coloring agents are added, resulting in so-called "blueing".
Although some improvements were made, it was not a fundamental improvement.

However, epoxy resin compositions have excellent mechanical and electrical properties as well as good adhesion and moisture resistance, so they have been widely used for sealing electronic components. If heat resistance deterioration can be improved, a revolutionary expansion of applications is expected, so the emergence of such a unique new material has been strongly requested by the electronics industry.

As a result of various studies on these points, the present inventors found that (:) curing acceleration is possible in a thermosetting resin composition mainly consisting of a mixture of an epoxy resin and an organic polybasic acid anhydride curing agent. By blending an alicyclic tertiary amine or its organic acid salt as an agent with a reducing, soluble organometallic compound, the synergistic effect of these agents dramatically accelerates curing with the use of a small amount of the organometallic compound. In addition, it has been found that discoloration at high temperatures of 150°C or higher can be significantly prevented.
11) Furthermore, if soluble hindered phenols and/or soluble organic phosphites are added as a discoloration prevention aid, in addition to the effects of the curing accelerator described above, the colorless transparency immediately after curing can be improved. The present inventors have discovered that a remarkable effect is observed in preventing discoloration when deteriorating at 120° C. for a long period of time, leading to the present invention.

The effects of hindered phenols and/or organic phosphites as discoloration prevention aids are as follows:
In conventional resin compositions, these properties may have been canceled out because they were insufficient and were considered to be only a secondary effect without being noticeable. Due to the mutually complementary effects of the different auxiliary agents, an epoch-making and excellent improvement in the heat resistance deterioration of colorless transparency was obtained to a degree that could never be predicted with conventional knowledge.

The present invention will be described in more detail below.

The epoxy resin used in the present invention may be of the known flat type, but may be one mainly composed of polyglycyl ether type of polyphenols (especially bisphenol A1 novola ivy), or one based on the physical properties of the cured product, adhesive properties, etc.
It is preferable because it has excellent curability, and alicyclic polyepoxide groups may also be used by appropriately blending them with these.

Furthermore, in the liquid resin composition, relatively low-viscosity monoepoxide compounds, polyepoxide compounds, etc. may be appropriately blended as reactive diluents.

Further, flame retardance may be achieved by appropriately using halogenated polyepoxide.

The above-mentioned epoxy resin can be suitably used in a liquid or solid form depending on the purpose, but even in the case of collapse, it is preferable to use a resin with as light a color as possible, preferably one with a color number of Gardner 1 or less.

A resin that is colored from the beginning is not desirable because the excellent effects of the present invention are greatly diminished.

As the organic polybasic acid anhydride used in the present invention, can any one that has good compatibility with the epoxy resin be used?
In particular, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, polyazelaic anhydride, dodecylsuccinic acid, etc. An aliphatic or alicyclic type is preferable.

Further, unsaturated aliphatic or aromatic compounds such as maleic anhydride, phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride can also be used as appropriate.

Further, halogen-containing materials such as chlorendic anhydride, hexachlorophthalic anhydride, hexabromo phthalic anhydride, etc. may be used as appropriate when flame retardancy is required.

As the above-mentioned organic polybasic acid anhydride, liquid or solid ones can be used as appropriate depending on the purpose, but even in the case of collapse, it is as light-colored as possible, preferably one with a color number of Gardner 1 or more. It is better to use

It is also possible to use a resin that has been partially esterified by adding a small amount of polyol, castor oil, etc. to improve its compatibility with the resin.

The alicyclic tertiary amines used in the present invention are at least one compound selected from the group of n''n'fudialkylpiperazines, diazabicycloalkanes, and diazabicycloalkenes; It may also be used as derived quaternary ammonium salts or as salts of organic or inorganic acids.

Diazabicycloalkanes especially have the general formula %, and any methylene group may be substituted with an alkyl group or an allyl group.

) is preferable.

Among these, triethylenediamine is particularly preferred.

As diazabischloroalkenes, in particular general (however, n
is 2-11. m is 2 to 6, and any methylene group may be substituted with an alkyl group or an allyl group.

) is preferable.

Among these, 1.8 diazabicyclo(5,4,O)wandecene-7 is particularly preferred.

Any inorganic or organic acid can be used to form a salt with the above various alicyclic tertiary amines, but in particular (
1) Aromatic, alicyclic or aliphatic carboxylic acids, oxycarboxylic acids, (:i) Aromatic and alicyclic are aliphatic sulfonic acids, G11) Aromatic alcohols, (iV) Carbonic acid, phosphoric acid, hydrochloric acid Inorganic acids such as are preferable.

The above-mentioned characteristics of the alicyclic tertiary amine are (i) strong basicity, so it is effective even when used in small amounts, (11) less likely to be oxidized and colored, and G11) stable with organometallic compounds. It is easy to form soluble complex salts.

The reducible soluble organometallic compound used in the present invention is at least one type of transition metal compound such as cobalt, manganese, vanadium, copper, tin, aluminum, and zirconium.

Although the above-mentioned organometallic compound may be of the common type, salts of organic acids, particularly C4-18 higher fatty acid metal salts and metal grates, particularly metal acetylacetonates are preferable.

Even in the case of collapse, it is necessary to have good compatibility with the epoxy resin.

Among these, divalent tin higher fatty acid salts or alkylated silver higher fatty acid salts (particularly dibutyltin dilaurate) are preferred.

When used alone, these organometallic compounds have a weak effect as a curing accelerator, and unless at least 10 parts are used per 100 parts of epoxy resin, complete curing cannot be achieved at temperatures below 100°C.

Moreover, it has the disadvantage of being significantly colored during long-term deterioration tests at high temperatures of 120° C. or higher, so conventionally it has not been used at all for products aimed at being colorless and transparent.

However, when these organometallic compounds are used in combination with the above-mentioned alicyclic tertiary amines, a curing accelerating effect can be obtained even with the addition of a very small amount, contrary to expectations, and the curing rate is significantly higher than when used alone. However, a cured product can be obtained that has little coloration and is resistant to discoloration in a deterioration test.

In other words, when alicyclic tertiary amine is used alone as a curing accelerator, it has the disadvantage of discoloration in a short period of time when exposed to high temperatures of 150°C or higher, but by using both together, discoloration can essentially be greatly reduced. It can be prevented.

However, if both are used together as curing accelerators, the initial colorless transparency of the cured product may be slightly inferior due to the color of the above-mentioned organometallic compound itself, and discoloration may occur when exposed to a slightly high temperature of about 130°C for a long period of time. It has the disadvantage that its properties are somewhat insufficient (see Table 1).

The organometallic compound of the present invention must have reducing properties and have a radical scavenging action.

The mechanism of curing acceleration is unknown, but non-reducing agents are undesirable because their curing accelerating effect is insufficient and, when used in combination with amines, their coloring prevention effect is poor.

The anti-discoloration agent used in the present invention is preferably one of hindered phenols having a radical scavenging effect and organic sulfides having a peroxide decomposition effect, or a mixture thereof.

The hindered phenols used in the present invention are preferably those having 1 to 10 phenol nuclei as shown in the following general formula.

(However, at least one of R2R' is t, butyl group,
A is a divalent or more aromatic, alicyclic, aliphatic hydrocarbon group, or divalent S.

) For example, 2,6 di-t-butylphenol, 3-methyl, 6
．． i Butylphenol, 2,6 dit, butyl, 4methylphenol, 2,2'methylenebis(4,methyl, 6t
・Butylphenol), 4゜4′butylidene bis(3・
methyl/6t-butylphenol), 2,2'thiobis(
4 methyl/6t-butylphenol), l, 3,5-trismethyl/2°4.6 tris(3,5-di-t-butyl/4-hydroxybenzyl)benzene, 1,3.5-tris(2
・Methyl, 4-hydroxy, 5t-butylphenol)butane, etc.

In particular, those having good compatibility with epoxy resins are preferred.

As the organic sulfides used in the present invention, thiobispropionic acid diesters are preferable, and in particular, C4-18
Diesters of higher aliphatic alcohols are preferred.

The amount of the alicyclic tertiary amine or its salt and the reducing soluble organometallic compound used in the present invention is 10
o, 02@4-20 parts (more preferably 0.05 parts to 0.5 parts) and 0.05 parts to 10 parts (
More preferably, the content is from 1 part to 10 parts.

If the amount added is less than this, a sufficient curing accelerating effect cannot be obtained, which is undesirable.If the amount added is larger than this, a sufficient curing accelerating effect can be obtained, but the coloration during curing, discoloration and collapse due to heat resistance deterioration may occur. It becomes noticeable and undesirable.

Both curing accelerators may be used after being mixed in a predetermined ratio in advance.

When the hindered phenols and organic phosphites used as discoloration inhibitors used in the present invention are used alone in tatami mats, they not only have the effect of accelerating hardening, but also have the effect of preventing discoloration during curing and preventing discoloration after heat-resistant deterioration. I can't get anything at all.

Further, even when the above-mentioned alicyclic amine or the above-mentioned organometallic compound is used in combination, the effect is insufficient (see Table 1).

However, by using alicyclic amines, organometallic compounds, and discoloration inhibitors in combination, their mutual effects produce superior effects that are far more unexpected than the results of using either alone or in combination. (See Table 1).

The discoloration inhibitor used in the present invention is desirably 0.05 parts to 30 parts (preferably 0.1 parts to 10 parts) per 100 parts of the epoxy resin.

If the amount is less than this, it will not be possible to sufficiently prevent discoloration during curing and discoloration after deterioration of heat resistance, which is undesirable.

On the other hand, if the amount is more than this, it is undesirable because it tends to be colored by the color of the anti-discoloration agent itself or to deteriorate the physical properties of the cured product.

In the present invention, it is generally desirable to use as few additives as possible in terms of transparency, resistance to heat deterioration, and electrical and mechanical properties.

In addition, in the case of using a heavy metal-based organometallic compound that is relatively easily colored in the present invention, an organic phosphite-based compound may be further used as an auxiliary discoloration inhibitor.

As such organic phosphite compounds, trialkyl, triaryl, and alkylaryl compounds can be used as long as they are compatible with the epoxy resin.

In addition, for the purpose of modifying the composition of the present invention, plasticizers such as saturated aliphatic linear polyesters, castor oil or its higher fatty acid esters, epoxidized soybean oil, DOP, and TCP are added to make the composition flexible. You may also add gender.

Further, the colorless transparency may be further improved by blending a small amount of a purple to blue coloring agent, so-called "blueing".

Further, if necessary, an appropriate coloring agent such as red or blue may be added.

In this case, the coloring agent may be either a dye or a pigment, but it is necessary that it has good dispersibility in the epoxy resin and that it is resistant to discoloration when tested for heat resistance deterioration.

When the composition of the present invention is used as a two-component composition consisting of a base agent and a curing agent, it is desirable to incorporate the curing accelerator on the curing agent side from the viewpoint of storage stability.

Other additives may be added to the side of the base resin and curing agent.

In addition, when used as a liquid type or solid molding material, the temperature should be kept at 15°C or less (preferably 5°C or less) for storage stability.
It is desirable to store it in

Examples will be explained below.

Example 1 80 parts of hexahydrophthalic anhydride molten at 50°C in 100 parts (weight, same below) of liquid epoxy resin (bisphenol A type, epoxy equivalent: 180) heated to 50°C
parts and 0.2 parts of 1-8 diazabicyclo(5,4,0) undecene-7, 1.0 parts of tin octylate (divalent), 4-
4'thiobis(3methyl/6tbutylphenol) 0.
Combine 2 parts and mix evenly.

This formulation gelled in 30 minutes at 120°C.

It should be noted that when either or both of the amine and the tin salt were missing from the above formulation, no gelation occurred at 120'C for 120 minutes.

The above-mentioned mixture was poured into a predetermined mold and heated under curing conditions of ioo°C-io dark time of 120°C for 3 hours or 150°C for 40 minutes to obtain a colorless and transparent cast product.

This cast product showed almost no discoloration even when heated at 150° C. for 4 hours.

Further, even in a deterioration test at 130° C. for 100 hours, only a slight yellowing occurred.

In addition, the above formulation lacking amine was heated at 150℃-
It turned slightly yellow when heated for 4 hours, and turned dark brown when heated at 130℃ for 1000 hours, and the one lacking tin salt was heated at 150℃
- It turns brown when heated for 4 hours, turns yellow significantly at 130°G - 1000 hours, and lacks hindered phenol.
0'C - Slight yellowing after heating for 4 hours at 130℃ - 1000
After heating for a long time, it yellowed significantly, and its collapse was insufficient compared to that of the three-weight compound.

In addition, cast products lacking amine discolor from the surface layer of the cast product, whereas cast products lacking tin salt discolor from the center of the cast product. It can be seen that the mechanism of preventing discoloration is fundamentally different.

Almost the same results were obtained by using 5 parts of dibutyltin diradiate instead of 1.0 part of tin (divalent) octylate.

Example 2 85 parts of methylhexahydrophthalic anhydride at 40°C and 1-8 diazabicyclo(5,3,0)decene were added to 100 parts of liquid epoxy resin (bisphenol A type, epoxy equivalent: 200) heated to 40°C. ~7 octylate salt 0.
5 parts, 0.5 parts of zirconium laurate, 0.1 part of aluminum acetylacetonate and 0.2 parts of dilauryl dithiopropionate, 0.2 parts of 2,6-di-t-butyl-4-methylphenol, and purple oil. A trace amount of soluble dye (concentration of about 1 ppm for blueing) is added and mixed uniformly.

The above mixture was poured into a predetermined shape and heated at 12°C for 3 hours to obtain a colorless and transparent cast product.

This cast product showed almost no discoloration even after heating at 1900 G for 1 hour.

Further, there was almost no discoloration even in a deterioration test at 125° C. for 2000 hours.

Example 3 Using a heated roll at 90°C, 100 parts of solid epoxy resin (bisphenol A type, epoxy equivalent: 400), 40 parts of tetrahydrophthalic anhydride, 1.0 part of triethylenediamine octylate, 0 parts of manganese stearate ．．
2 parts of calcium stearate, 1.0 part of dilauryl thiodipropionate, and 0 parts of didecylphenyl phosphite were kneaded to obtain a uniform solid molding material.

The above-mentioned molding material has a storage stability of 6 months or more when stored at 5° C. or lower.

Further, the above molding material was molded under pressure in a mold at 180° C. for 3 to 5 minutes to obtain a colorless and transparent molded product.

This molded article showed almost no discoloration even when heated at 190° C. for 1 hour.

Further, almost no discoloration was observed in a deterioration test at 130° C. for 500 hours.

Claims (1)

[Scope of Claims] 1. In a thermosetting resin composition mainly consisting of an epoxy resin and an organic polybasic acid anhydride curing agent, (1) alicyclic tertiary amines or their A colorless transparent epoxy resin composition with excellent heat deterioration resistance, characterized by containing a salt, a reducing soluble organometallic compound, and (11) a soluble hindered phenol and/or a soluble organic sulfide as a discoloration inhibitor. thing. 2. The epoxy resin composition according to claim 1, wherein the alicyclic tertiary amine is at least one type of diazabicycloalkenes. 3. The epoxy resin composition according to claim 1 or 2, wherein the reducible soluble organometallic compound is a divalent tin higher fatty acid salt. 4. The aliphatic tertiary amine or its salt and the reducible soluble organometallic compound are used in amounts of 0.05 parts to 0.5 parts and 0.0 parts, respectively, based on 10 parts (by weight, the same applies hereinafter) of the epoxy resin.
Claim 1 in which 1 part to 10 parts are added
The epoxy resin composition according to item 1, 2, or 3. 5 The discoloration inhibitor is 0.0 parts per 100 parts of epoxy resin.
The epoxy resin composition according to claim 1, 2, 3 or 4, wherein 5 parts to 2 parts are added.