JPH046207B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an epoxy resin composition that provides a cured product with an excellent balance of heat resistance and flexibility. [Technical background of the invention and its problems] Epoxy resins exhibit excellent properties such as adhesiveness, chemical resistance, and electrical properties, so they are used in a wide range of applications such as adhesives, paints, and electrical insulation materials. In recent years, usage conditions have become increasingly severe, and it has become increasingly difficult to use conventional epoxy resin compositions. One of the usage conditions that is becoming increasingly severe is heat resistance, and compositions such as adhesives, paints, and electrically insulating materials that have even higher heat resistance than existing ones are desired. On the other hand, there is generally a correlation between the heat resistance and flexibility of a cured epoxy resin, and as the heat resistance of the cured product increases, the cured product loses its flexibility and becomes brittle. [Object of the Invention] The present invention was made in view of the above circumstances, and its purpose is to provide an epoxy resin composition having excellent heat resistance and flexibility. [Summary of the Invention] Epoxy resins are generally cured using a combination of amines, acid anhydrides, and phenols, which are generally called curing agents, but in terms of chemical resistance, they are produced through a curing reaction. Bonds are strongly polar,
Cured products using phenols are chemically more stable and superior to products cured using amines and residual anhydrides, which provide a chemically active structure. Therefore, in order to improve the heat resistance of epoxy resin, the present inventors investigated the method of using phenols, which have excellent chemical resistance, as a curing agent. Compared to things,
The present invention was completed by discovering a composition with an excellent balance between heat resistance and flexibility. That is, the present invention comprises (A) Components: phenols and crotonaldehyde;
Condensation product (B) with an aldehyde selected from cinnamaldehyde Component: Polyepoxy compound (C) Component: Curing catalyst For 100 parts by weight of the condensation product of component (A) above, (B)
An epoxy resin composition in which the component polyepoxy compound is blended in a ratio of 10 to 250 parts by weight, and the curing catalyst as component (C) is blended in a ratio of 0.1 to 5 parts by weight to 100 parts by weight of component (B). . It provides: In the present invention, the condensation product of component (A) is
2 to 2 to 1 mole of aldehyde, phenol
Usually 50-180°C, preferably 50-130°C in the presence of an acidic catalyst in a proportion of 100 mol, preferably 10-30 mol.
It is obtained by reacting at a temperature of 1 to 6 hours. After the reaction is complete, the acid catalyst is removed from the system or neutralized with an alkali such as caustic soda, caustic potash, calcium hydroxide, soda carbonate, or potassium carbonate, and then water and excess phenol are removed from the reaction product. removed. General methods such as washing with a solvent and removal by distillation are used for dehydration and dephenolization, but in the case of distillation, the temperature of the condensate must be
It is preferable to carry out the reaction at a temperature of 200°C or lower. Examples of the phenols include phenol, orthocresol, metacresol, paracresol, orthobromophenol, metabromophenol, parabromophenol, catechol, resorcinol, hydroquinone, xylenol, alkylphenol, phenylphenol, bisphenol, and the like. . These can be used alone or in combination of two or more. Acid catalysts used in the reaction include mineral acids such as sulfuric acid, hydrochloric acid, and hydrogen bromide, sulfonic acids such as para-toluenesulfonic acid, benzenesulfonic acid, phenolsulfonic acid, and xylene sulfonic acid, oxalic acid, malonic acid, succinic acid, Conventional novolak-forming catalysts can be used, such as carboxylic acids such as acetic acid, monochloroacetic acid, dichloroacetic acid, and the like. The amount of catalyst used varies depending on the type of catalyst, reaction conditions, etc., but it is usually desirable to use 0.1 to 10% by weight based on 100 parts by weight of phenol. This condensation reaction does not require a particular solvent, but benzene, toluene, xylene, propyl ether, butyl ether, tetrahydrofuran,
There is no problem in using an inert solvent such as chloroform. The molecular weight of the condensate obtained is about 250 to 2000. Next, the polyepoxy compound of component (B) is a compound having two or more epoxy groups in the molecule,
For example (i) diglycidyl ether of bisphenol A;
Products include Epicoat 827, 828, 834, 864, 1001, and Epicoat 828, manufactured by Yuka Ciel Epoxy Co., Ltd.
1004, 1007, Ciba Araldite GY250,
6099, Union Carbide's ERL2774, Dow Chemical's DER332, DER331, DER661 (all product names), etc. (ii) Epoxyphenol novolac;
154, DOW Chemical's DEN438, DEN448, Ciba's Araldite EPN1138, DEN1139 (all product names), etc. (iii) Epoxy cresol novolac; products include Yuka Ciel Epoxy Co., Ltd.'s Epicote 181, Ciba's Araldite EPN1138, DEN448, etc. Araldite ECN1235, Araldite 1273, Araldite 1280
(both are trade names), etc., etc., as well as epoxy resins obtained from phthalic acid or hexahydrophthalic acid and epichlorohydrin, epoxy resins obtained from parahydroxybenzoic acid and epichlorohydrin, and epoxy resins obtained from aromatic amines such as toluidine or aniline and epichlorohydrin. Examples thereof include vinyl cyclohexene dioxide, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, epoxidized polyolefin epoxidized by a peroxidation method, and epoxidized polybutadiene. In addition, when using the above-mentioned component (B), there is no problem in using a monoepoxy compound as appropriate.
Examples of the monoepoxy compound include styrene oxide, cyclohexene oxide, propylene oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, octylene oxide, and dodecene oxide. Component (B) is not necessarily limited to only one type, and two or more types may be used. Examples of curing catalysts for component (C) include quaternary ammonium salts such as tetraethylammonium chloride, tetraethylammonium bromide, and cetyltrimethylammonium chloride; benzyldimethylamine, triethylamine, 2,4,
Tertiary amines such as 6-(trisdimethylaminomethyl)-phenol; 2-methyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-
Amine-based curing catalysts such as imidazoles such as methylimidazoleazine and imidazoleazine having 11 carbon atoms; Lithium salts such as lithium chloride, lithium bromide, and lithium iodide; Complex compounds consisting of triethylamine and boron trifluoride; Thiazole Examples include the following. These components (A) to (C) contain 10 to 250 parts by weight of component (B), preferably 100 parts by weight, per 100 parts by weight of component (A).
230 parts by weight, and 0.1 to 5 parts by weight, preferably 0.5 to 5 parts by weight of component (C) per 100 parts by weight of component (B).
It is used in a proportion of 3 parts by weight. The blending amount of component (B) is 10 parts by weight for 100 parts by weight of component (A).
If the amount is less than 1 part by weight, the resulting cured product will have insufficient strength, which is a practical problem. Moreover, if it exceeds 250 parts by weight, the heat resistance of the cured product will be significantly reduced. Furthermore, the amount of component (C) relative to 100 parts by weight of component (B) is
If the amount is less than 0.1 part by weight, the curing speed will be extremely slow, making it impractical. On the other hand, if it exceeds 5 parts by weight, a gelation reaction may occur during mixing, which is not preferable. In addition to these components (A) to (C), inorganic fillers, glass fibers, pigments, ultraviolet absorbers, solvents, phenol as a curing point depressant, and the like can be blended. To mix components (A) to (C), if component (B) is a liquid, it is sufficient to simply mix them together, but if both components (A) and (B) are solid at room temperature, use a roll, This is done by heating and mixing using a kneader or the like, or by dissolving it in a solvent. Curing is accomplished by heating the composition at 50-200°C for 0.5-10 hours. [Effects of the Invention] The epoxy resin composition of the present invention has excellent curability,
Moreover, the obtained cured product has excellent heat resistance, flexibility, and water resistance. Therefore, this epoxy resin composition can be advantageously used in various fields such as various moldings, adhesives, coatings, sealants, and laminations similar to those of conventional epoxy compositions. A more specific explanation will be given below with reference to Examples, but these Examples are merely illustrative and the present invention is not limited by the Examples. Example of Preparation of Condensate of Component (A) Preparation Example 1 1700 g (18.1 mol) of phenol was placed in a reactor equipped with a reflux condenser, a stirrer, a thermometer and a dropping funnel.
and 8.5 g of 47% hydrogen bromide solution, and while stirring the contents, 126 g (1.8 mol) of crotonaldehyde was added dropwise from the dropping funnel at 70°C over 30 minutes. At the end of the dropwise addition, the temperature rises to 90°C due to an exothermic reaction. Subsequently, the reaction was continued at this temperature for 3 hours. At this time, the conversion rate of crotonaldehyde reached 100%. Next, the reflux condenser of the reactor was replaced with a cooling separator and the temperature inside the system was gradually raised from 90°C to 150°C,
Subsequently, heat to 180°C under a reduced pressure of 5 mmHg,
Hydrogen bromide, water and unreacted phenol are distilled off,
557 g of a white-yellow product was obtained. When this product was analyzed by high performance liquid chromatography and mass spectrometry, it was found that 1,1,3-
A condensation product containing 59% by weight of tris(hydroxyphenyl)-butane and having a molecular weight of 170-900 was obtained, the curing point of which was 120°C. Production Example 2 1700 g of phenol, 8.5 g of 47% hydrogen bromide and 238 g of cinnamaldehyde were placed in the same apparatus as in Example 1, and the same reaction as in Example 1 was carried out to produce a white-yellow condensate (2).
I got 702g. This condensate (2) was found to be 1,1,3-
It was a condensate containing 64% by weight of tris(hydroxyphenyl)-3-phenylpropane and had a molecular weight of 180 to 800, and its curing point was 120°C. Production Example 3 1500g of orthocresol was placed in the same equipment as Example 1.
36% hydrogen chloride water 7.5g, crotonaldehyde 126g
was charged, and the same reaction as in Example 1 was carried out to obtain 620 g of a white-yellow condensate (3). As a result of high performance liquid chromatography analysis and mass spectrometry, this condensate (3) contains 60% by weight of 1,1,3-tris(3-methyl-4hydroxyphenyl)-butane and has a molecular weight of 180.
-800 condensate with a curing point of 109°C. Examples 1 to 8, Comparative Examples 1 to 2 Condensates (1) to (4) obtained in Examples 1 to 4, phenol novolac (manufactured by Gunei Chemical Co., Ltd., curing point 72°C), bisphenol A as a polyepoxy compound Diglycidyl ether (Epicote 828” (manufactured by Yuka Ciel Epoxy; epoxy equivalent: 190) and epoxy phenol novolak “Epicote 154” (manufactured by Yuka Ciel Epoxy: epoxy equivalent 174)) N,N-dimethylbenzylamine as a curing accelerator. were mixed in the ratio shown in Table 1, degassed for 5 minutes under a reduced pressure of 1.0 mmHg, poured into a casting sheet metal mold, and heated at 160°C for 2 minutes.
It was pre-cured for an hour and then heated at 180°C for 3 hours to completely cure it to obtain a cured product measuring 150 mm in length, 150 mm in width and 30 mm in thickness. Table 1 shows the physical properties of the obtained cured product. The measurements were conducted according to the following method. Heat distortion temperature: ASTM D-648 Bending strength: JIS K-6911 Manufacturing example 4 1,1,3-tris(3,5-dimethyl-4-
Hydroxyphenyl)butane 2,6-xylenol was added to the same equipment as in Production Example 1.
1500g 36% hydrogen chloride water 7.5g crotonaldehyde
126 g was charged and the same reaction as in Production Example 1 was carried out to obtain 730 g of yellow-red condensate (4). This condensate (4) was found to be 1,1,3-tri(3,5-dimethyl-4-
It is a condensate with a molecular weight of 350 to 450 containing 90% by weight of (hydroxyphenyl)butane and has a curing point of 190℃.
It was hot.

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Claims (1)

[Scope of Claims] 1 (A) Component: Condensation product of phenols and aldehydes selected from crotonaldehyde and cinnamaldehyde (B) Component: Polyepoxy compound (C) Component: Curing catalyst Above (A) (B) per 100 parts by weight of the condensation product of the components.
An epoxy resin composition in which the component polyepoxy compound is blended in a ratio of 10 to 250 parts by weight, and the curing catalyst as component (C) is blended in a ratio of 0.1 to 5 parts by weight to 100 parts by weight of component (B). .