JPH0160496B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention deals with the reaction of a polyphenol having a spiro ring such as 3,9-bis(p-hydroxyphenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane with epihalohydrin or β-methylepihalohydrin. The present invention relates to a method for isolating polyglycidyl ether produced in this manner. The polyglycidyl ether purified by carrying out the present invention provides a cured product with excellent heat resistance, so it is called carbon fiber reinforced resin (hereinafter referred to as "CFRP").
It is useful as a resin material for electrical parts, a casting material for electrical parts, or an encapsulating material. Traditionally, epoxy resin has been used for its excellent electrical insulation properties,
Due to its adhesive properties, mechanical strength, and heat resistance, it can be used as a sealing material for electrical and electronic components, as a matrix material for CFRP, as a paint,
Widely used in adhesives, etc. Such a polyepoxy compound has the general formula, Bifunctional polyepoxy compounds in which the epoxy group is located para to the spiroacetal ring are known (U.S. Pat. No. 3,347,871, US Pat. No. 3,347,871).
(Refer to each specification of No. 3388098). The method for producing a polyepoxy compound represented by the above formula disclosed in these specifications is to heat and dissolve a polyphenol having a spiroacetal ring and an excess amount of epichlorohydrin at 60°C using ethanol as a solvent, and then % sodium hydroxide aqueous solution and performs a dehydrohalogenation reaction to produce polyglycidyl ether. and,
The method for purifying the polyglycidyl ether is to distill off unreacted epichlorohydrin and ethanol after the reaction under reduced pressure, add methyl isobutyl ketone to reduce the viscosity of the product, and then wash it several times with water to remove salt, etc. This is a conventional method for purifying the organic layer by separating the organic layer and then removing methyl isobutyl ketone from the organic layer under reduced pressure. However, in this separation and purification method, the polyglycidyl ether having a spiroacetal ring does not have sufficient solubility in methyl isobutyl ketone, resulting in emulsion formation during washing with water, resulting in a decrease in yield. Furthermore, the obtained polyglycidyl ether contains 5 to 10% by weight of a polymer and has a high saponifiable chlorine content of 0.1 to 0.5% by weight. A high content of saponifiable chlorine impairs the curing speed of the polyglycidyl ether, lowers the electrical properties such as arc resistance of the cured product obtained from the glycidyl ether, and damages metals such as copper circuits that are encapsulated and laminated. It is undesirable because it causes corrosion. Moreover, the presence of a high molecular weight substance has the disadvantage of lowering the heat distortion temperature and mechanical strength of the resulting cured product. As a result of intensive studies to obtain high-purity polyglycidyl ether, the present inventors noticed that polyepoxy compounds containing spiroacetal rings exhibit significantly different dissolution behavior compared to conventional polyepoxy compounds. After the completion of the reaction, the reaction product solution is cooled, and the polyepoxy compound containing a spiroacetal ring is precipitated from the reaction product solution containing epihalohydrin or β-methylepihalohydrin, and is isolated by crystallization. It was discovered that a polyepoxy compound (polyglycidyl ether) of a single composition can be separated and purified, and the present invention was completed. That is, the present invention provides general formula () A polyphenol compound represented by and an excess amount of epihalohydrin or β-methyl epihalohydrin in the presence of a catalyst at a temperature of 40 to 130°C, and
The water by-produced by the reaction is removed from the reaction system by azeotroping with epihalohydrin or β-methylepihalohydrin, and the epihalohydrin or β-methylepihalohydrin from which the water has been separated is reacted while being returned to the reaction system to produce a compound represented by the following formula (). polyglycidyl ether The epihalohydrin or β-methyl epihalohydrin solution containing the polyglycidyl ether is then cooled to below 60°C to precipitate the product polyglycidyl ether, and the precipitated polyglycidyl ether is converted into epihalohydrin or β-methyl epihalohydrin. The present invention provides a method for isolating and purifying polyglycidyl ether, which is characterized by separating it from epihalohydrin. [Wherein, Y is hydrogen, an alkyl group having 1 to 18 carbon atoms,
an alkoxy group, an aralkyl group, or an aryl group, and n is an integer of 1 to 4]. In the practice of the present invention, the following two methods can be mentioned as methods for producing polyglycidyl ether before being subjected to purification. (1) A one-step method in which an addition reaction and a dehydrohalogenation reaction are carried out at once between a polyphenol having a spiroacetal ring represented by the general formula () and epihalohydrin or β-methylepihalohydrin using an alkali. (2) A method in which the polyphenol and epihalohydrin or β-methyl epihalohydrin are first subjected to an addition reaction using a catalyst such as a quaternary ammonium salt, and then a dehydrohalogenation reaction is performed using an alkali. Danpo. Of these two methods, the latter two-stage method is preferred in terms of yield and product quality. Next, each raw material will be described. As described in US Pat. No. 3,388,098, a polyphenol having a spiroacetal ring represented by the general formula () is prepared by mixing an acid in a ratio of 1 mole of pentaerythritol to 2 moles of an aldehyde or ketone having a hydroxyl group at the para position. It is obtained by reacting at 70-95°C and atmospheric pressure in the presence of a catalyst. The above aldehyde or ketone is 4
-Hydroxybenzaldehyde, vanillin, 3-
Chloro-4-hydroxybenzaldehyde, 3-
Methyl-4-hydroxybenzaldehyde, 4-
Examples include hydroxyacetophenone and 4-hydroxybenzophenone. Examples of epihalohydrin and β-methylepihalohydrin include epichlorohydrin, epipromohydrin, β-methylepichlorohydrin, and β-methylepipromohydrin. The amount of epihalohydrin or β-methyl epihalohydrin used is 3 to 30 mol, preferably 4 to 30 mol, per 1 mol of raw material polyphenol.
It is 10 moles. Epihalohydrin or β-methyl epihalohydrin used in excess is distilled, separated and recovered from water, and returned to the reaction system for reuse. Examples of the alkali used include sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, potassium carbonate, and sodium carbonate, with sodium hydroxide or potassium hydroxide being preferred. Furthermore, quaternary ammonium salts used in the two-step process include, for example, tetramethylammonium chloride, tetraethylammonium bromide,
Examples include triethylmethylammonium chloride, tetraethylammonium iodide, cetyltriethylammonium bromide, and the like. Particularly preferred is tetramethylammonium chloride or tetraethylammonium bromide. The amount of alkali to be used is at least equivalent, preferably 1.05 to 1.5 equivalents, per equivalent of phenolic hydroxyl group of the raw material polyphenol. The alkali is usually added to the reaction system in the form of solid particles or as an aqueous solution. Further, the amount of the quaternary ammonium salt, etc. used is usually about 0.1 to 3.0 parts by weight per 100 parts by weight of the raw material polyphenol compound. The reaction temperature varies depending on the type of reactants, but in the case of a one-step process, it is 60 to 150℃, preferably 80 to 120℃.
℃, and the reaction time is 1 to 4 hours. Also,
In the two-step process, the first addition reaction is 40° to 150°
The temperature is preferably 70° to 140°C, and the subsequent ring-closing reaction is carried out at 40° to 150°C, preferably 40° to 80°C.
Reaction time is 1 to 3 hours. The subsequent ring-closing reaction in the one-stage method and the two-stage method is carried out under normal pressure or reduced pressure (50 to 200 mmHg) by continuously removing the generated water from the system by azeotroping with epihalohydrin or β-methyl epihalohydrin, and then After the by-produced water is removed, unreacted epihalohydrin or β-methylepihalohydrin is returned to the reaction system while carrying out a ring-closing reaction. After the completion of the epoxidation reaction by the one-step method or the two-step method, the epichlorohydrin or β-methyl epihalohydrin solution containing the desired polyglycidyl ether is cooled to a temperature lower than the reaction temperature, and the desired polyglycidyl ether is crystallized. The polyglycidyl ether having a spiroacetal ring represented by the above formula (2) can be obtained by precipitating it, separating it from epihalohydrin or β-methyl epihalohydrin, and drying it. The cooling temperature varies depending on the target polyglycidyl ether, but in the general formula (), when Y is H and n is a polyglycidyl ether of 4,
60℃ or less, preferably -40℃ to +20℃, Y
When is a polyglycidyl ether in which is OCH ₃ and n is 1, the temperature is 30°C or less, preferably -40°C to +20°C. The separated and purified polyglycidyl ether is thoroughly washed with water using a mixer to remove the by-produced alkali halide salt, and then dried. Further, if necessary, recrystallization is performed using a solvent such as dioxane. The epihalohydrin or β-methyl epihalohydrin in the liquid from which the polyglycidyl ether is separated can be reused by purification. The polyglycidyl ether purified in this way contains almost no polymer, has an extremely low saponifiable halogen content, and provides a cured product with high mechanical strength. This purified spiroacetal ring-containing polyglycidyl ether is cured by itself or mixed with other epoxy compounds with a curing agent. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 3,9-bis-(4-hydroxyphenyl)
172.0 g (0.5 mol) of 2,4,8,10-tetraoxaspiro[5.5]udecane, 463 g (5.0 mol) of epichlorohydrin, and 1.7 g of tetramethylammonium chloride were placed in a 1-piece container equipped with a stirrer, a cooler, and a thermometer. The mixture was placed in a three-necked flask, and the addition reaction was carried out in an oil bath at a temperature of 117°C for 2 hours. Then, after cooling the internal temperature of the reaction system to 60°C,
A water separator was attached and 42 g (1.05 mol) of sodium hydroxide was added in solid form. The pressure inside the reaction system was reduced to 100 mmHg, and the produced water was removed by azeotropy with epichlorohydrin, and the separated epichlorohydrin was continuously returned to the reaction system, while the ring-closing reaction was carried out for 2 hours. After the reaction, the reaction product solution was left at room temperature for 2 hours to release the desired product, 3,9-bis[p-
(2,3-epoxypropoxy)phenyl]-2,
4,8,10-tetraoxaspiro[5.5]undecane was precipitated and crystallized. After separately collecting unreacted epichlorohydrin, the target product was washed with water using a mixer to completely remove by-product common salt. Recrystallization was performed using dioxane to obtain 201.1 g of the desired product as white crystals (yield: 88.2%). The melting point of this crystal was about 175-176°C, and its gel permeation chromatogram was as shown in FIG. Also, its epoxy equivalent is
228, which was identical to the epoxy equivalent value of 228 calculated by corresponding this product to the above compound. For 100 parts by weight of this polyglycidyl ether,
27.2 parts by weight of diaminodiphenylsulfone (hardening agent) were mixed at 180°C, defoamed for 10 minutes under a reduced pressure of 1.0 mmHg, poured into a casting sheet mold, and heated at 180°C.
Pre-cure for 4 hours at
A cured product having the physical properties shown in Table 1 was obtained. In addition, the test method for physical properties is as follows. Heat deformation temperature ASTM D-648 Bending strength JIS K-6911 Bending modulus 〃 Tensile strength 〃 Tensile modulus 〃 Izot impact strength 〃 (notched) Comparative example 1 The method described in Example 4 of U.S. Patent No. 3,388,098 Polyglycidyl ether was produced and purified. That is, 1110 g was placed in a 3-four-necked flask equipped with a thermometer, stirrer, cooling tube, and dropping funnel.
(12.0 mol) of epichlorohydrin, 344 g of ethanol and 688 g (2.0 mol) of 3,9-bis-
(4-hydroxyphenyl)-2,4,8,10-
Prepare tetraoxaspiro [5.5] undecane,
Heated to 60°C. To this, 184 g of 50% aqueous sodium hydroxide solution was added dropwise in the following order. First hour 18.4g Next 30 minutes 18.4g Next hour 128.8g Last hour 18.4g After stirring for 20 minutes, unreacted epichlorohydrin and ethanol were removed under reduced pressure and the remaining slurry was mixed with methyl isobutyl ketone. Add 900g and 500ml
Washed with water. After the pH became 8 or less, the solvent was removed under reduced pressure to obtain 608 g of the desired product (yield: 66
%). The melting point of this product is 158°C and the epoxy equivalent is 242
(Theoretical value 228). Moreover, the gel permeation chromatogram is as shown in FIG. 1, and it is understood that it contains some high molecular weight substances. Example 2 3,9-bis-(4-hydroxyphenyl)
3,9-bis(4-
Hydroxy-3-methoxyphenyl)-2,4,
8,10-tetraoxaspiro[5.5]undecane
Using 202 g (0.5 mol), and carrying out the ring-closing reaction at 50
℃ and 80 to 100 mmHg, the physical properties 3,9-bis-[4-(2,
3-Epoxypropoxy-3-methoxy)phenyl]-2,4,8,10-tetraoxaspiro[5.5]undecane was obtained (yield 78%). A gel permeation chromatogram of this product is shown in FIG. Incidentally, if this product is the above-mentioned polyglycidyl ether, the theoretical value of the epoxy equivalent is 258 (actual value 229). Comparative Example 2 In Comparative Example 1, instead of 172.0 g of 3,9-bis-(4-hydroxyphenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane,
Other than adding 84 g of 50% sodium hydroxide to 202 g of 3,9-bis-(4-hydroxy-3-methoxyphenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane in the following order: Similarly, Table 1
A polyglycidyl ether with the physical properties shown in (yield 79%) was obtained.First hour 8.4g Next 30 minutes 8.4g Next hour 58.8g Last hour 8.4g Gel permeation chromatography of this polyglycidyl ether The grams were as shown in Figure 2. Example 3 In Example 1, 463 g of epichlorohydrin
193.8 g (yield: 80.1%) of polyglycidyl ether having an epoxy equivalent of 242 and a melting point of 161° was obtained in the same manner, except that 532.5 g (5.0 mol) of β-methylepichlorohydrin was used instead of (5.0 mol).

【table】

[Table] - means not measured

[Brief explanation of drawings]

Figure 1 shows 3,9-bis-[p-(2,3-epoxypropoxy)phenyl]-2,4,8,10-tetraoxaspiro[5.5] separated and purified in Example 1 and Comparative Example 1. Figure 2 shows the gel permeation chromatogram of undecane, 3,9-bis-[4-(2,
3-Epoxypropoxy-3-methoxy)phenyl-2,4,8,10-tetraoxaspiro [5.5]
This is a gel permeation chromatogram of undecane.

Claims (1)

[Claims] 1. General formula [Wherein, Y is hydrogen, an alkyl group having 1 to 18 carbon atoms,
an alkoxy group, an aralkyl group, or an aryl group, and n is an integer of 1 to 4] and an excess amount of epihalohydrin or β-methylepihalohydrin at a temperature of 40 to 130°C in the presence of a catalyst. So, and
The water produced by the reaction is azeotroped with epihalohydrin or β-methyl epihalohydrin to remove it from the reaction system, and the epihalohydrin from which the water has been separated is returned to the reaction system while reacting to produce polyglycidyl ether. It is characterized by precipitating the product polyglycidyl ether by cooling an ether-containing epihalohydrin or β-methylepihalohydrin solution to 60°C or lower, and then separating the precipitated polyglycidyl ether from the epihalohydrin or β-methylepihalohydrin. A method for isolating and purifying polyglycidyl ether.