JPH033692B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyglycidyl ether containing a spiroacetal ring, which provides a cured product with excellent solubility, an excellent balance between elongation and rigidity, and excellent heat resistance and impact resistance.
The polyglycidyl ether obtained by carrying out the present invention is useful as a matrix resin for CFRP, a sealant for electronic parts, a casting material, a laminated material, and a binder for paints. Epoxy resins have excellent heat resistance, electrical insulation, chemical resistance, and mechanical properties, and are therefore widely used in fields such as paint adhesives, sealants, and structural materials. In particular, in recent years, carbon fiber composite materials (CFRP) have mechanical strength and elastic modulus equal to or higher than metals, and can be made lighter. It is used as a base material for the transportation industry, such as golf shafts, fishing rods, skis, etc., and is expected to continue to develop greatly in the future. Polyepoxy compounds currently used as matrix resins for CFRP include diglycidyl ether of bisphenol A [Epicote 828,
Epicote 1004 etc.: Yuka Ciel Epoxy Co., Ltd. trade name], aminophenol polyepoxide [ELM
−120: Sumitomo Chemical Co., Ltd. trade name], methylene dianiline tetraepoxide [YH-434: Toto Kasei Co., Ltd. trade name], cresol novolac polyepoxide [Epicote 154: Yuka Ciel Epoxy Co., Ltd. trade name] ,
Examples include orthocresol novolac epoxide [EOCN104S: Nippon Kayaku Co., Ltd. trade name]. Although cured products obtained from these polyepoxy compounds have sufficient heat resistance, the reality is that as resins for reinforcing carbon fibers, improvements in flexibility and impact resistance are desired. Polyepoxy compounds having a spiroacetal ring are known as polyepoxy compounds that provide cured products with high flexibility. For example, USP 3,128,255 discloses a polyepoxy compound represented by the following formula, and the heat distortion temperature of the cured product obtained from this is 147 to 170°C.
Therefore, it lacks heat resistance as a CFRP resin. In addition, USP No. 3347871 and USP No. 3388098 include (A). A general formula produced by further reacting (B) epichlorohydrin with a divalent phenol obtained by reacting a monovalent phenol whose aldehyde group is in the para position with respect to the phenolic hydroxyl group and pentaerythritol, [In the formula, Y is H, Cl, _CH3 , and n is 0 to 2
is an integer of ] is disclosed. However, although this polyepoxy compound provides a cured product with excellent heat resistance and impact resistance, there is still room for improvement in flexibility, and general-purpose solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, It has poor solubility in tetrahydrofuran, etc., and is of little practical use as a polyepoxy compound for propregs or paints that are diluted with a solvent. In the technique of USP 3,347,871, the present inventor discovered that 4-oxy-3
- It has been found that polyglycidyl ether obtained by using methoxybenzaldehyde and 4-oxybenzaldehyde in combination has excellent solubility in the above-mentioned general-purpose solvents and provides a cured product with good heat resistance, flexibility, and elongation-rigidity balance. , arrived at the present invention. That is, the present invention provides a bisphenol having a spiroacetal ring obtained by reacting a mixture of 4-oxy-3-methoxybenzaldehyde and 4-oxybenzaldehyde in a molar ratio of 5/95 to 95/5 with pentaerythritol, Furthermore, it provides a method for producing polyglycidyl ether by reacting epihalohydrin or β-methyl epihalohydrin. In the practice of this invention, the bisphenol mixture having a spiroacetal ring is 4-oxy-3
- Pentaerythritol is added to a mixture of 5 to 95 mol %, preferably 20 to 80 mol % of methoxybenzaldehyde and 95 to 5 mol %, preferably 80 to 20 mol % of 4-oxybenzaldehyde in the presence of a catalyst.
It can be easily obtained by heating to 200°C, preferably 80 to 150°C to carry out dehydration condensation. As for the charging ratio of raw materials, a stoichiometric amount of aldehyde is required per mole of pentaerythritol, but an excess amount of aldehyde may be used. Moreover, it is preferable to continuously remove water produced from the reaction system by azeotropy using a solvent. As the solvent used, aromatic hydrocarbons such as benzene, toluene, and xylene are economical, but in addition to these, N, which is a better solvent for aldehydes, is used.
N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, tetrahydrofuran, dioxane, dimethylsulfoxide, etc. may be used in combination. The catalyst is preferably p-toluenesulfonic acid, and other commonly used dehydration condensation catalysts such as oxalic acid, zinc acetate, hydrochloric acid, and sulfuric acid may also be used. Generally, the use of a large amount of 4-oxy-3-methoxybenzaldehyde facilitates the dissolution of the polyglycidyl ether compound in the solvent and improves the elongation of the cured product of the polyglycidyl ether compound. Furthermore, 4-oxybenzaldehyde acts to improve the heat resistance and mechanical strength of the resulting cured polyglycidyl ether. This bisphenol mixture is difficult to separate. The components are believed to be a mixture of bisphenols represented by the following formulas () to (), estimated from the raw materials. [In the formula, R represents hydrogen and R' represents a methoxy group]. Next, the divalent bisphenol mixture obtained by this reaction is reacted with epihalohydrin or β-methyl epihalohydrin (hereinafter both will be referred to as "epihalohydrin") to produce polyglycidyl ether. ,
A known epoxidation method can be employed. For example the following
Methods (1) to (3) can be mentioned. (1) A bisphenol mixture and excess "epihalohydrin" are reacted in the presence of an alkali metal hydroxide, and the addition reaction of "epihalohydrin" to the bisphenol mixture and the ring-closing reaction to form an epoxy ring are performed simultaneously. A one-step method for producing polyglycidyl ethers. (2) The bisphenol mixture and excess "epihalohydrin" are subjected to an addition reaction in the presence of a catalyst such as a phosphonium salt or a quaternary ammonium salt, and then an alkali metal hydroxide is added to perform a ring-closing reaction to form polyglycidyl. A two-step process for producing ether. (3) A solvent method in which an aqueous alkali metal hydroxide solution is added at a low temperature of room temperature to 80°C, using a bisphenol mixture, excess “epihalohydrin” and a reaction accelerating solvent such as alcohol to carry out addition and ring-closing reactions simultaneously. . The molecular weight distribution of polyglycidyl ethers obtained by these methods tends to increase in the order of (1), (2), and (3), and it is possible to select one of these epoxidation methods depending on the purpose. It is. In the case of epoxidation method (1), the reaction is carried out at 60-150℃,
Preferably it is carried out at a temperature in the range of 80-120°C.
The amount of "epihalohydrin" added to the bisphenol mixture containing a spiroacetal ring is 2
The amount is 20 times to 20 times, preferably 8 times to 12 times. The alkali metal hydroxide is used in an amount of at least equimolar, preferably 1.05 to 1.5 times the hydroxyl group of the bisphenol mixture. In epoxidation method (2), the first stage addition reaction is 40~
The reaction is carried out at 150°C, preferably 70-140°C, and the subsequent ring-closing reaction is carried out at 20-150°C, preferably 40-80°C. The amount of catalyst is based on the bisphenol mixture.
0.1-5 mol %, the amounts of "epihalohydrin" and alkali metal hydroxide are the same as in the one-stage process. In addition, in the case of epoxidation method (3), the solvent used is 0.2 to 5.0 mol% based on "epihalohydrin",
Preferably 0.5 to 2.0 mol%, reaction temperature is room temperature to 80
Preferably, it is carried out at .degree. The latter stage ring-closing reaction in the one-stage method and the two-stage method may be carried out under normal pressure or reduced pressure (50 to 200 mmHg) while continuously removing the generated water from the system by azeotroping with "epihalohydrin". . After the completion of these reactions, the reaction solution is filtered through a filter aid (for example, celite, etc.) to remove by-product salts, and the unreacted "epihalohydrin" is recovered under reduced pressure to obtain the product or the reaction solution is removed. After recovering unreacted "epihalohydrin" by reducing the pressure of the liquid, it is dissolved in an organic solvent that is sparingly soluble in water, such as methyl isobutyl ketone, toluene, etc., and this solution is brought into contact with water or hot water to remove inorganic substances such as common salt. Purification is carried out by dissolving impurities in an aqueous phase and then distilling off the organic solvent. Examples of the raw material "epihalohydrin" include epichlorohydrin, epibromohydrin, β-methylepichlorohydrin, and β-
Examples include methyl epibromohydrin. Further, examples of the alkali metal hydroxide include potassium hydroxide and sodium hydroxide. Furthermore, examples of catalysts used in the first-stage addition reaction in the two-stage process include quaternary ammonium salts and phosphites. Examples of quaternary ammonium salts include tetramethylammonium chloride, tetraethylammonium bromide, triethylmethylammonium chloride,
Examples include tetraethylammonium iodide and cetyltriethylammonium bromide. Phosphites include triphenylphosphonium halides (eg iodide, bromide, chloride), triphenylethylphosphonium diethyl phosphate and phosphonates. A particularly preferred catalyst is tetramethylammonium chloride or tetraethylammonium bromide. The polyglycidyl ether thus obtained is generally a mixture of polyglycidyl ethers represented by the following formulas () to (). [In the formula, R is hydrogen, R' is methoxy group, EX is

[Formula] and R'' is H or a methyl group]. However, depending on the reaction and purification conditions, the following formula () ~
It may contain 40% by weight or less of high molecular weight substances such as those shown in parentheses. [In the formula, R is H, R' is a methoxy group, R'' is H or _CH3 , and m is an integer from 1 to 5.] The polyglycidyl ether obtained by carrying out the present invention has a relatively low softening property. This polyglycidyl ether is not only useful as a matrix resin for CFRD because it gives a cured product with an excellent balance between elongation and elastic modulus. Since it dissolves in ethyl acetate, methylene chloride, etc., it is useful as a raw material for paints and prepreg varnishes.In addition, this polyglycidyl ether can be used alone or in combination with other epoxy compounds as an epoxy resin. That is, if this bifunctional polyglycidyl ether mixture is used alone or in combination with one or more other epoxy compounds, a curing (crosslinking) reaction is performed with an appropriate curing agent. , it becomes a cured product with high heat resistance, flexibility, and impact resistance.There are no particular restrictions on other epoxy compounds used in combination, and various epoxy compounds are used in combination depending on the application. Examples of other epoxy compounds include polyglycidyl ethers such as bisphenol A or promobisphenol A, phthals, polyglycidyl esters such as cyclohexanedicarboxylic acid, polyglycidyl amines such as aniline or methylene dianiline, amino acids, etc. Examples include epoxidized phenols and glycidyl ethers such as phenol novolac and cresol novolac.As the curing agent for curing this polyglycidyl ether mixture, various curing agents similar to those used in known epoxy resins can be used. For example, aliphatic amines, aromatic amines, heterocyclic amines, Lewis acids such as boron trifluoride and their salts, organic acids, organic acid anhydrides, urea or their derivatives, and polyamides. Mercaptans, etc. Specific examples include aromatic amines such as diaminodiphenylmethane, diaminodiphenyl sulfone, 2,4-diamino-m-xylene; 2-methylimidazole, 2,4,5-
Triphenylimidazole, 1-cyanoethyl-
Imidazole or imidazole substitutes such as 2-methylimidazole, or salts of these with organic acids; organic carboxylic acids such as fumaric acid, trimellitic acid, hexahydrophthalic acid; phthalic anhydride, endomethylenetetrahydrophthalic anhydride, hexahydro anhydride Organic acid anhydrides such as phthalic acid; urea derivatives such as dicyandiamide, melamine, and guanamine;
Aliphatic polyamines such as triethylenetetramine, diethylenetriamine, xylylenediamine, and isophoronediamine, and adducts of these with epoxy compounds such as ethylene oxide and propylene oxide, or acrylic compounds such as acrylonitrile and acrylic acid, etc. can be used. In addition to curing agents, this polyglycidyl ether also contains plasticizers, organic solvents,
Various additives such as reactive diluents, extenders, fillers, reinforcing agents, pigments, flame retardants, thickeners and flexibility agents can be incorporated. The cured epoxy resin obtained from the polyglycidyl ether obtained by carrying out the present invention has a better elongation-modulus balance, better impact resistance, and better heat resistance than conventional bisphenol A-based epoxy resins. CFRP matrix resin,
It is useful as an electronic component encapsulant, casting agent, laminated material, and paint. 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. Production Examples 1 to 6 of Divalent Polyphenol Example 1 Into a four-necked flask equipped with a thermometer, nitrogen inlet tube, stirring device, and water separator, 4-oxy-3
-Methoxybenzaldehyde (vanillin) 76g
(0.5 mol), 4-oxybenzaldehyde 61g
(0.5 mol), 68 g of pentaerythritol, 30 g of para-toluenesulfonic acid, 500 ml of toluene and N,
150 ml of N-dimethylformamide was charged. Dehydration condensation was carried out by heating to 120°C while flowing nitrogen gas into the system. The produced water was continuously removed by azeotroping with toluene, and the reaction was terminated when the theoretical amount was reached (18 ml). After the reaction was completed, the solution of the obtained product was poured into water in Step 5, and the precipitated crystals were separated and dried to obtain 147.7 g (yield 79.0%) of pale red crystals of bisphenol containing a spiroacetal ring. Ta. The melting point of this crystal was 189°C to 204°C. In addition, as a result of analyzing this crystal by liquid chromatography, the following general formula () was found. It turned out to be a mixture consisting of 25% R=R'=H and 50% R=R'=OCH ₃ . Example 2 Light reddish brown crystals of bisphenol containing a spiroacetal ring were prepared in the same manner as in Example 1, except that the amounts used were changed: 38 g (0.25 mol) of vanillin, 91.5 g (0.75 mol) of p-hydroxybenzaldehyde.
133.4g (yield 74.3%) was obtained. The melting point of this crystal was 206°C to 221°C. In addition, as a result of liquid chromatography analysis, in formula (), 54.2% of R=R'=H;R=R'=
8.3% of OCH ₃ ; 37.5% of R=H, R′=OCH ₃ . Example 3 137.1 g of light brown crystals of bisphenol containing a spiroacetal ring were prepared in the same manner as in Example 1 except that the amounts used were changed to 114 g (0.75 mol) of vanillin and 30.5 g (0.25 mol) of p-hydroxybenzaldehyde.
(yield 70.5%) (melting point 182°C to 201°C). As a result of liquid chromatography analysis, in formula (), R
=R'=H was 8.0%; R=R'=OCH ₃ was 56.7%; R=H, R'=OCH ₃ was 35.3%. Example 4 3,9-bis(p-hydroxyphenyl) was prepared in the same manner as in Example 1 except that 122 g (1.0 mol) of p-hydroxybenzaldehyde was used instead of 76 g of vanillin and 61 g of p-hydroxybenzaldehyde.
-2,4,8,10-tetraoxaspiro [5.5]
A white powder of undecane was obtained (melting point 251-253°C). Example 5 3,9-bis(p-chlorohydroxyphenyl) was prepared in the same manner as in Example 1 except that 150 g (1 mol) of 3-chloro-4-hydroxybenzaldehyde was used instead of 122 g (1.0 mol) of p-hydroxybenzaldehyde. -2,4,8,10-tetraoxaspiro[5.5]undecane was obtained. Example 6 3,9-bis(p-2-methylhydroxyl) was prepared in the same manner as in Example 4, except that 133 g (1 mol) of 3-methyl-4-hydroxybenzaldehyde was used instead of 122 g (1 mol) of p-hydroxybenzaldehyde. Enyl)-2,4,8,10-tetraoxaspiro[5.5]undecane was obtained. Example 7 Example 4 except that 122 g (1 mol) of vanillin was used instead of 122 g of p-hydroxybenzaldehyde.
3,9-bis(4-oxy-3-
White crystals of (methoxyphenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (melting point
175°C) was obtained. Example 1 187 g (0.5 mol) of the spiroacetal ring-containing bisphenol obtained in Example 7 above, 462.5 g (5.0 mol) of epichlorohydrin, and 40 g of tetramethylammonium bromide were placed in a 1-tub system equipped with a thermometer, a cooler, and a stirring device. The mixture was charged into a three-necked flask, and the reaction was carried out under reflux (117°C) for 2 hours. Thereafter, the reaction solution was cooled to 60° C., a water separator was attached, 42 g (1.05 mol) of sodium hydroxide was added, and a ring-closing reaction was carried out under reduced pressure (150 to 100 mmHg). The produced water is continuously removed from the system by azeotroping with epichlorohydrin, and the produced water is reduced to 18ml.
The reaction was terminated when the temperature reached . 0.1 to 50 mmHg of epichlorohydrin in the final reaction,
After collection at 60 to 110°C, 1 methyl isobutyl ketone was added to make the product into a slurry, and the product was thoroughly washed with 500 ml of water to remove by-produced sodium chloride. Methyl isobutyl ketone was distilled off under reduced pressure from the product solution after washing with water using a rotary evaporator to obtain 228 g of a pale yellow solid. The epoxy equivalent of this product was 280, and the softening temperature was 72-78°C. Example 2 An epoxidation reaction was carried out in the same manner as in Example 1, except that 179.5 g of bisphenol having a spiroacetal ring obtained in Example 2 was used as the bisphenol, and 212 g of a pale yellow solid was obtained (epoxy equivalent:
260, softening point 75-85℃). Example 3 An epoxidation reaction was carried out in the same manner as in Example 1, except that 194.5 g of the spiroacetal ring-containing bisphenol obtained in Example 3 was used as the bisphenol, and 223 g of a pale yellow solid was obtained (epoxy equivalent:
292, softening point 61-70℃). Comparative Examples 1-4 Bisphenols obtained from Examples 4-7 above
A polyglycidyl ether having the physical properties shown in Table 1 was produced in the same manner as in Example 1, except that 0.5 mol was used as bisphenol. Solubility test in solvents Examples 1 to 3 and Comparative Examples 1 to 4 and general-purpose diglycidyl ether of bisphenol A “Epicote 828” [trade name, manufactured by Yuka Ciel Epoxy Co., Ltd.
5 parts by weight of epoxy equivalent (approximately 186) were mixed with 95 parts by weight of various solvents shown in Table 1, and the solubility of the polyglycidyl ether was investigated. The results are shown in the same table.

【table】

Claims (1)

[Claims] 1 5/95 to 95/5 of 4-oxy-3-methoxybenzaldehyde and 4-oxybenzaldehyde
In the molar ratio mixture, bisphenol having a spiroacetal ring obtained by reacting pentaerythritol with epihalohydrin or β-
A production method characterized by producing polyglycidyl ether by reacting methyl epihalohydrin. 2. The manufacturing method according to claim 1, wherein the bisphenol is a mixture of bisphenols represented by the following () to (). [In the formula, R represents hydrogen and R' represents a methoxy group].