JPH0395215A - Curing agent composition for epoxy rein and epoxy resin composition containing same - Google Patents

Abstract

PURPOSE:To prepare a storage-stable curing agent compsn. which gives a colorless, transparent and homogeneous cured product of an epoxy resin when the product is cured under specified curing conditions by mixing an acid anhydride, a specific zinc carboxylate, and specific glycidyl compds. and thermally modifying the resulting mixture. CONSTITUTION:An acid anhydride, a zinc carboxylate of formula I, and glycidyl compds. of formula II and/or III are mixed and the resulting mixture is thermally modified to give a curing agent compsn. for an epoxy resin. The compsn. is excellent in the solubility in an epoxy resin compsn. and storage stability, and can give a colorless, transparent cured product even under fast curing conditions at 120 deg.C or higher. In formula I, R1 and R2 are each (1-10C alkyl- substd.) phenyl, naphthenic acid residue, (hydroxylated) 1-12C alkyl, or alkenyl; in formula II, R3 is cyclohexyl, (1-20 alkyl-substd.) phenyl, or 5-20C alkyl; and in formula III, R5 is (1-20C alkyl-substd.) cyclohexyl, (1-20C alkyl-substd.) phenyl, 1-20C alkyl, or alkenyl.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an organic carbon@zinc curing accelerator having excellent solubility with acid anhydride curing agents and epoxy resins, and further relates to the curing accelerator. An acid anhydride curing agent for epoxy resin suitable for optical applications, such as optical materials such as optical lenses, prisms, and transparent flat plates, light emitting elements such as light emitting diode encapsulants, and optical disk substrates; The present invention relates to an epoxy resin composition.

(Prior art) Epoxy resin has excellent mechanical, electrical, thermal, and chemical properties, so it is used in many fields such as casting materials and sealing materials. The one-component type is superior in terms of workability, but the liquid type, which combines epoxy resin with a curing agent such as an acid anhydride and a curing accelerator, has a short shelf life, so it is generally made of epoxy resin, etc. Main agent (
1) and a curing agent (II) consisting of an acid anhydride, a curing accelerator, etc.
) are separated and (1) and (II) are mixed during curing, a two-part formulation is used.

In recent years, cured epoxy resins cured with acid anhydride curing agents have come to be used for optical applications such as optical lenses, prisms, light emitting diodes, and optical disk substrates.

Since cured epoxy resins for such optical applications are strongly required to be colorless and transparent, strict performance requirements are also imposed on the curing agents used for these applications.

Acid anhydride curing agents generally contain curing accelerators such as
■Tertiary amines or imidazoles, etc. and/or their organic carboxylates, ■Tertiary amines or imidazoles, etc. and/or combination systems of their organic carboxylates and organic carboxylic acid metal salts, etc. However, the cured product is transparent but colored due to tertiary amines, etc., and does not satisfactorily satisfy optical applications (Problem M to be solved by the present invention). It is already known that a cured epoxy resin using zinc organic carboxylate as an agent is colorless and transparent (27th National SAMPE Sym
posium, MAY. 4-6 1982). However, organic zinc carboxylates have a drawback of poor solubility in acid anhydrides and/or epoxy resins as curing agents. For this reason, the curing agent composition mixed with the acid anhydride does not become a homogeneous liquid, and phase separation of the organic zinc carboxylate and cloudiness due to the phase separation occur. Furthermore, in the case of epoxy resin compositions in which organic zinc carboxylate is blended with epoxy resin and ia anhydride, epoxy resin and/or organic zinc carboxylate are used.
Or, due to poor solubility in acid anhydrides, there were problems such as uneven curing and poor workability.

In preliminary studies conducted by the present researchers, cured epoxy resins using organic zinc carboxylates are colorless and transparent, especially at 12
Although it has been confirmed that it has excellent colorless transparency even under high temperature and rapid curing conditions at temperatures above 0°C, it may also have poor solubility in acid anhydrides or epoxy resins and uneven curing. I admit it. Therefore, it is practically difficult to use an acid anhydride curing agent containing only zinc organic carboxylate as a curing agent, and it is necessary to mix tertiary amines, imidazoles, etc. with the acid anhydride, or Organic carboxylic acid g. The reality is that a small amount of lead is used in combination, and the organic zinc carboxylate is used only in a small amount that can be dissolved in acid anhydrides, epoxy resins, etc.

In view of these problems, the inventors of the present invention
In order to develop a curing agent that gives a colorless and transparent uniform cured product even under fast curing conditions of preferably 130° C. or higher, and has excellent solubility in epoxy resin compositions and storage stability, we have conducted extensive studies, The present invention has been completed.

represents a branched Ct-C21 alkyl group or argenyl group) (Means for Solving the Problems) The present inventors added one or more acid anhydrides to one or more acid anhydrides represented by formula (A). Organic carboxylic acid zinc and general formula (B)
and/or an acid anhydride curing agent composition consisting of a modified acid anhydride obtained by mixing a predetermined amount of one or more glycidyl compounds represented by formula (C) and denaturing the mixture by heating. We have discovered that scales can be easily dissolved in epoxy resins without impairing their hardening function. (R., R, are the same or different, phenyl group, C l
"Ct. phenyl group having a straight chain or branched alkyl group, naphthenic acid residue, C0 to C21 straight chain or branched alkyl group or alkenyl group, straight chain having a hydroxyl group or (R, cyclohexyl group, phenyl group, C
1-C2. A phenyl group having a straight chain or branched alkyl group or C, to C2. (represents a straight chain or branched alkyl group) n (R8 is a cyclohexyl group, Cl to C2. A cyclohexyl group having a straight chain or branched alkyl group, a phenyl group, C, to C,. A straight chain or branched alkyl group phenyl group, C1 to C2, which represents a linear or branched alkyl group or alkenyl group> The ratio of the acid anhydride to the organic carboxylic acid zinc used for modifying the acid anhydride (hereinafter referred to as the acid anhydride zinc ratio) > is (D
), the range is 10 to 250, preferably 2
It is between 0 and 100. Acid anhydride zinc ratio=Z/X...(D
) (X is the number of moles of zinc organic carboxylate as in the case of the glycidyl zinc ratio shown in formula (E), Z is the Durham equivalent number of acid anhydride) If the ratio is 10 or less, the mechanical properties of the cured product If it is 250 or more, the curing reaction rate of the epoxy resin is slow and it is unsuitable. The ratio of the glycidyl compound represented by the formulas (B) and (C) and the zinc organic carboxylate used for modifying the acid anhydride (hereinafter referred to as the glycidyl zinc ratio) is represented by the formula (E), and the ratio is 2-9, preferably 3-7. If it is less than 2, the organic zinc carboxylate glycidyl zinc ratio = Y/X... (E) (X is the number of moles of the organic zinc carboxylate, Y is the number of moles of the glycidyl compound). If the solubility is 9 or higher, the solubility is good, but various properties other than transparency of the cured epoxy resin, such as glass transition temperature and moisture resistance, decrease, making it difficult to use in practice. It becomes difficult. As the organic zinc carboxylate used in the present invention, those exemplified by the following general formula (A) are effective.

? R t and R2 are the same or different, phenyl group, C
t~C,. A phenyl group having a straight chain or branched alkyl group, a naphthenic acid residue, a C1-cit straight-chain or branched alkyl group or alkenyl group, a straight-chain or branched C1-C2 alkyl group or alkenyl having a hydroxyl group. Specifically, zinc acetate, zinc hexanoate, zinc 2-ethylhexanoate, zinc laurate, zinc valmitate, zinc stearate, zinc ricinoleate, zinc benzoate, p
Examples include zinc monotert-butylbenzoate, and zinc naphthenate having a monocyclic, bicyclic, or tricyclic carbon number of 6 to 20. These can be used alone or in combination of two or more.

As the glycidyl compound used in the present invention, (B)
and/or one or more glycidyl compounds corresponding to formula (C) are used. Specifically, compounds corresponding to formula (B) include octanoic acid glycidyl ester, 2
-Ethylhexanoic acid glycidyl ester, Versat
ic 5 and Versatic 10 (Shell Chemical (
Examples include neoacid glycidyl ester, benzoic acid glycidyl ester, and p-tert-butylbenzoic acid glycidyl ester, which are glycidyl esters of carboxylic acids such as those manufactured by Co., Ltd.). Specific examples of compounds corresponding to formula (C) include methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, nonylphenyl glycidyl ether, etc. is exemplified. The acid anhydride used in the present invention is one or more polybasic acid carboxylic acid anhydrides, specifically phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
Methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, 3.6-endomethylenetetrahydrophthalic anhydride, l-isoprobyl-4-methyl-bicyclo[2.2.0]octane-5-ene-2.3 -Dicarboxylic acid anhydride and its hydride, 3,6-endomethylenetetrahydrophthalic anhydride, maleated allocimene and its hydride, maleated myrcene and its hydride, methylnadic anhydride and its hydride, pyromellit anhydride Acid, dodecenylsuccinic anhydride, poly(ethyl octadecanedioic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bis(anhydrotrimellitate), glycerol tristrimeritate anhydride, anhydrous Examples include het acid and tetrapromophthalic anhydride.

A method for producing a curing accelerator made of a modified zinc organic carboxylate is to add a predetermined amount of an acid anhydride and a glycidyl compound to a zinc organic carboxylate, preferably in the presence of an inert gas such as nitrogen gas, at a temperature of 60 to 200°C. is 70~150℃
and stir for 0.5 to 10 hours. Through such operations, a curing accelerator made of modified organic zinc carboxylate can be easily obtained. The modified organic carbon wi zinc obtained by the present invention has a good function as a curing accelerator, and in the storage stability test of the curing accelerator at 40°C, no phenomena such as phase separation occurred even after 3 months or more. Although the structure of the curing accelerator made of modified zinc organic carboxylate is not clear, and no deterioration in curing accelerating function is observed, it is easy to dissolve in acid anhydrides and epoxy resins, such as zinc octylate. , methyl hexahydrophthalic acid, and 2-ethylhexanoic acid glycidyl ester, the glycidyl zinc ratio shown in formula (E) was set to 3, and the acid anhydride zinc ratio shown in formula (D) was set to 3, and the mixture was dissolved in nitrogen gas. , when denatured by stirring at 100°C for 1 hour, its IR spectrum shows the appearance of absorption <1708 cm-'' based on free carboxyl groups and <1554 cm-'' based on zinc octylate compared to before modification. Judging from the reversal of the absorption intensity at 1632 cm and 1632 cm, it is presumed that the organic zinc carboxylate, acid anhydride, and/or glycidyl compound form something like a complex or oligomer. Next, an epoxy resin composition can be obtained by appropriately mixing the acid anhydride curing agent composition containing the modified organic zinc carboxylate prepared according to the present invention, an epoxy resin, and other additives. The epoxy resin composition thus obtained was
By heating and curing at a temperature of about 00 to 170°C, a cured product with good transparency and no curing unevenness can be obtained.

Furthermore, this cured product showed very little deterioration in transparency even when subjected to a long-term heating test at about 125°C. Any type of epoxy resin can be used in the present invention as long as it has the desired effects of the present invention.
Specifically, bisphenol type epoxy resin obtained from bisphenol A or bisphenol F and epihalohydrin, 3.4-epoxycyclohexylmethyl-3
", 4゛Alicyclic epoxy resins such as monoepoxycyclohexane carboxylate, novolac type epoxy resins,
Glycidyl ether type epoxy resins such as polypropylene glycol diglycidyl ether, butyl diglycidyl ether, phenyl diglycidyl ether, glycidyl ester type epoxy resins such as adivic acid diglycidyl ester, diglycidyl ester of hexahydrophthalic acid and tetrahydrophthalic acid, etc. Illustrated. These can be used alone or in combination of two or more. An epoxy resin, an acid anhydride curing agent composition containing the modified zinc organic carboxylate of the present invention, and, if necessary, a metal salt of an organic carboxylic acid other than zinc, a metal acetylacetonate, a tertiary amine, and an imidazole. curing accelerators such as
Flexibility agents, modifiers, dyes, pigments, bluing agents,
Inorganic and/or organic fillers such as light diffusing agents, antifoaming agents, coupling agents, coloring inhibitors such as antioxidants and reducing agents,
Additives such as flame retardants and mold release agents can be included. The curing accelerator for epoxy resin, epoxy resin curing agent, and epoxy resin compound obtained by the present invention can be used for optical purposes,
For example, optical equipment such as optical lenses, prisms, transparent flat plates, etc.
Light-emitting elements such as light-emitting diode encapsulants, optical disk substrates,
Adhesives for light modulators and optical fibers, encapsulants for light-receiving elements such as photodiodes and phototransistors, encapsulants for LSIs and ICs such as ultraviolet-erasable EP-ROMs, optical coating materials used for touch panels and solar cell surfaces, etc. It can be used for sealing light-emitting/light-receiving elements such as photocouplers.

Next, the present invention will be explained in detail with reference to Examples.

(Example) Example 1 Methylhexahydrophthalic anhydride {trade name: Rikashid Me-HHPA, Shin Nippon Rika Co., Ltd.} was placed in a 300 ml four-tube flask equipped with a stirring device, a cooling tube, a nitrogen gas inlet tube, and a thermometer. (hereinafter abbreviated as Me-HHPA) 16
8g (The acid anhydride zinc ratio shown in formula (D) is 33.,3
}, zinc 2-ethylhexanoate {trade name: octope zinc, manufactured by Hope Pharmaceutical Co., Ltd.) 10.5 g, neo acid glycidyl ester {trade name: Neotoh} D (epoxy equivalent: 24
0 to 265), manufactured by Totoka Co., Ltd.) 25. Og {(E)
The glycidyl zinc ratio shown in the formula is 3,3} and heated to 100℃.
After stirring for 1 hour under nitrogen gas flow, the mixture was cooled to room temperature to obtain a colorless, transparent and uniform curing agent composition. 100 parts by weight of the curing agent composition was easily dissolved in 1100 parts by weight of bisphenol A diglycidyl ether {trade name: Ebicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., hereinafter abbreviated as DGEBA. The composition was sealed in a glass bottle and heated at 40°C for 40
The solubility was observed after storage for several days, and it was a colorless, homogeneous, transparent liquid. The results are shown in Table 1. Examples 2 to 9 The same procedure as in Example 1 was conducted except that the type of organic zinc carboxylate, glycidyl compound or acid anhydride, glycidyl zinc ratio, acid anhydride zinc ratio, and stirring temperature were changed. However, in the case of Example 5 in which tetrahydrophthalic anhydride (hereinafter abbreviated as THPA) was used as the acid anhydride, the melting point was 102°C.
Therefore, the solubility test was evaluated at 105°C. The results are shown in Table 1. Examples 10 to 14 100 parts by weight of the curing agent composition obtained in Examples 1 to 9 and DGE
Part by weight of BAIOO was vigorously stirred for 1 minute, then defoamed under reduced pressure, and the solubility at that time was evaluated. Thereafter, it was cured at a predetermined temperature for 5 hours to prepare a cured product measuring 5 x 20 x 40 mm, and the curing unevenness in appearance and coloring properties were evaluated by measuring light transmittance at 400 nm and 800 nm. The cured product is 1
After heating at 25° C. for 300 hours, the light transmittance was measured again.

However, since the curing agent composition of Example 5 in which THPA was used as the acid anhydride was solid at room temperature, it was mixed with DGEBA at 105° C. for 1 minute and evaluated in the same manner.
The results are shown in Table 2.

Comparative Examples 1 to 4 A curing agent composition was produced in the same manner as in Example 1, except that zinc organic carboxylate was heated in the presence of an acid anhydride. However, only the solubility of comparative PA4 using THPA was evaluated at 105°C. The results are shown in Table 1. Comparative Example 5 A curing agent combination was produced in the same manner as in Example 1 except that the mixture was mixed at 25°C. The results are shown in Table 1. Comparative Examples 6 to 9 Using the same equipment as in Example 1, Me-HHPA168
g, 2-ethyl-4-imidazole (hereinafter referred to as 2E
Add 1.0 g of 4MZ) or 1.0 g of 1,8-diazabisic[5.4.0]undecene-7 (hereinafter abbreviated as DBU) and mix and dissolve at 80°C for 1 hour. 100 parts by weight of the obtained curing agent and 100 parts by weight of DGEBA were mixed at room temperature and cured in the same manner as shown in Examples 10 to 14 to evaluate transparency. The results are shown in Table 2. Comparative Example 10 Using the same apparatus as in Example 1, 52 g of THPAl was added to
DBUI. Example 1
It was cured in the same manner as described in sections 0 to 14, and the transparency was evaluated. The results are shown in Table 2.

Comparative Examples 11 to 14 100 parts by weight of the hard agaric preparations obtained in Comparative Examples 1 to 6 and DG
Parts by weight of EBAIOO were mixed at room temperature, a cured product was prepared in the same manner as described in Examples 10 to 14, and the solubility, uniformity, and transparency of the cured product were evaluated. However, THPA
was mixed at 105°C. The results are shown in Table 2.

(Effects of the invention) The modified organic carboxylic acid zinc curing accelerator obtained in the present invention easily dissolves in acid anhydrides and epoxy resins, does not cause deterioration such as phase separation even during long-term storage, and The acid anhydride curing agent combination containing the acid zinc curing accelerator does not cause deterioration such as phase separation even during long-term storage. The cured epoxy resin product is colorless and transparent with no uneven hardening.

Claims (2)

[Claims] (1) One or more acid anhydrides, one or more organic carboxylic acid zinc represented by general formula (A), and one or more glycidyl compounds represented by general formula (B) and/or (C). A curing agent composition for epoxy resins comprising a modified acid anhydride obtained by mixing and heating denaturation. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (R_1 and R_2 are the same or different, phenyl group, C
A phenyl group having a straight chain or branched alkyl group of _1 to C_1_0, a naphthenic acid residue, a straight chain or branched alkyl group or alkenyl group of C_1 to C_2_1, a straight chain or branched alkyl group of C_1 to C_2_1 having a hydroxyl group or alkenyl group) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(B) (R_3 is a cyclohexyl group, a phenyl group, C_1 to C
(Represents a phenyl group having a straight chain or branched alkyl group of _2_0 or a straight chain or branched alkyl group of C_5 to C_2_0) ▲There are numerical formulas, chemical formulas, tables, etc.▼...(C) (R_5 is a cyclohexyl group, C_1-C_2_0 A cyclohexyl group having a straight chain or branched alkyl group, phenyl group, C_1-C_2_0 A phenyl group having a straight chain or branched alkyl group, C_1-C_
2_0 indicates a straight chain or branched alkyl group or alkenyl group) (2) One or more acid anhydrides include organic zinc carboxylate represented by formula (A) of claim 1 and formula (B) and/or formula (C) of claim 1. An epoxy resin composition containing as an essential component a modified acid anhydride obtained by mixing one or more of the glycidyl compounds shown and heat-modifying the mixture.