JPS6219766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thermosetting oil-modified phenol formaldehyde resin for impregnation, and the present invention relates to a method for producing a thermosetting oil-modified phenol formaldehyde-based impregnating resin. The purpose is to obtain an insulating laminate material with good electrical properties and punching workability by impregnating the molding material (hereinafter referred to as "material for molding") and then laminating the material for molding under heat and pressure. Generally, insulating laminate materials are required to have good punching properties at room temperature or relatively low temperatures near room temperature, but they can be obtained by pressurizing a molding material impregnated with phenol formaldehyde resin while heating. Insulating laminated materials have poor punching properties. In order to improve this drawback, oil-modified phenolic aldehyde resins modified with drying oils such as tung oil have come to be widely used as impregnating resins, thereby improving the punching workability of laminated materials. However, the most effective tung oil is a natural product, and its production is affected by climate and other natural factors, resulting in significant fluctuations in price and quality.The disadvantage is that the price and quality of the product, the laminated wood, also fluctuates. It was hot. Therefore, instead of being modified with tung oil, an attempt was made to use an oil-modified phenol formaldehyde resin modified with tall oil fatty acid polyhydric alcohol ester (A) as an impregnating resin. This tall oil fatty acid polyhydric alcohol ester (A) is easily obtained from tall oil fatty acids, which are by-products of the pulp and paper industry, so it is inexpensive and has little variation in quality, eliminating the disadvantages of using tung oil. However, tall oil fatty acid polyhydric alcohol ester (A) has a lower degree of unsaturation than tung oil, so it is difficult to react with phenol, and the addition rate of phenol is low, so tall oil fatty acid polyhydric alcohol ester (A) has a lower degree of unsaturation than tung oil. The impregnating resin obtained by reacting alcohol ester (A) with phenol and then reacting with formalin to form a resol has a small molecular weight, so it is impregnated into a molding material, and the molding material is heated. The laminated material obtained by pressure molding has the drawback of inferior punching workability and electrical properties compared to the laminated material obtained by using tung oil-modified phenol formaldehyde resin as the impregnating resin. The present inventor's proposal was developed as a result of various studies and studies aimed at solving the problems of oil-modified phenol formaldehyde impregnation resins modified with tung oil or tall oil fatty acid polyhydric alcohol ester (A) as described above. 200 tall oil fatty acid polyhydric alcohol ester (A), general formula R-
(NCO) _o (wherein R represents a phenylene group, a diphenylmethane core group, or an alkylene group substituted with one or more groups selected from the group consisting of a phenyl group, an alkyl group, and a hydrogen group, n
represents a positive integer from 2 to 4. ) One or more compounds selected from the group of compounds shown in
After producing a modified tall oil fatty acid polyhydric alcohol ester (B) by reacting 0.2 to 10 parts by weight, the modified tall oil fatty acid polyhydric alcohol ester (B) is reacted with phenol in the presence of a Friedel-Crafts catalyst. When this reaction product is reacted with formalin in the presence of an alkaline catalyst to form a resol, a molding material is impregnated with the impregnating resin, and this molding material is heated and pressurized, resulting in an insulating laminate. The present invention was completed based on the discovery that an insulating laminate material having excellent punching workability and electrical insulation properties can be obtained by using phenol formaldehyde resin modified with tung oil as the impregnating resin. That is, in the present invention, when modifying resol type phenol formaldehyde resin, instead of using tung oil or tall oil fatty acid polyhydric alcohol ester (A) as conventionally used, tall oil fatty acid polyhydric alcohol ester (A) is Formula R-(NCO) _o (wherein R is a phenylene group, diphenylmethane core group, or alkylene group substituted with one or more groups selected from the group consisting of phenyl group, alkyl group, and hydrogen group) , where n is a positive integer from 2 to 4) Modified tall oil fatty acid polyhydric alcohol ester ( It is characterized by the use of B). The tall oil fatty acid polyhydric alcohol esters used in the present invention are fatty acids obtained by refining crude tall oil obtained in the kraft pulp manufacturing process by rectification, ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. This refers to the ester produced by the reaction of ester, and also includes mixtures of these and cases in which unreacted fatty acids partially coexist during the esterification reaction. The reason why the hydroxyl value of the tall oil fatty acid polyhydric alcohol ester is set to 20 to 200 is that when the hydroxyl value is less than 20, the number of hydroxyl groups that react with isocyanates is small, so the molecular weight of the resulting impregnating resin does not increase, and therefore the product This is because the punching workability of the laminated material is not sufficient, and the reason why the hydroxyl value is limited to 200 or less is because if it is 200, it can react with a sufficient amount of isocyanate.
This is because it is meaningless to make the value larger than 200, and also requires a large amount of polyhydric alcohol, which is uneconomical. General formula R-(NCO ₎ used in the present invention
(However, in the formula, R represents a phenylene group, a diphenylmethane nuclear group, or an alkylene group substituted with one or more groups selected from the group consisting of a phenyl group, an alkyl group, and a hydrogen group, and n is 2 to Examples of the compound represented by (representing a positive integer of 4) include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and the like.
The amount of this isocyanate added should be adjusted to a hydroxyl value of 20 or more.
200 tall oil fatty acid polyhydric alcohol ester 100
The range of 0.2 to 10 parts by weight is 0.2 parts by weight.
This is because if the amount is less than 1 part by weight, the molecular weight of the resulting impregnating resin cannot be sufficiently increased, and as a result, the product laminate does not exhibit satisfactory punching workability. Also, the reason why it is limited to 10 parts by weight or less is that 10 parts by weight can sufficiently increase the molecular weight, but if it is used in a larger amount, the reaction system may gel, making it impossible to obtain a homogeneous substance. It's for a reason. Since the impregnating resin of the present invention has increased molecular weight by converting tall oil fatty acid polyhydric alcohol having hydroxyl groups into urethane, the product laminate obtained using this impregnating resin exhibits sufficient punching workability. It also has excellent electrical properties such as electrical insulation. In the present invention, when phenol is allowed to act on the reaction product of tall oil fatty acid polyhydric alcohol ester and isocyanates, there is no problem even if tung oil or other drying oil is used in combination. The present invention will be explained below with reference to Examples. Example 1 A tall oil fatty acid pentaerythritol ester with a hydroxyl value of 28 (an acid value of 8, an iodine value of
122, color number (Heliege) 6) was charged, the temperature was raised to 90°C while passing nitrogen gas, and 1.5 g of tolylene diisocyanate was added. After keeping it at 100℃ for 2 hours, the temperature was raised to 150℃, and 900g of phenol was mixed.
Add 15 g of boron trifluoride phenol complex (25%) and react at 150°C for 4 hours. 670 g of 35% formalin aqueous solution was added to the obtained reaction product, 30 g of 28% ammonia water was added as a catalyst, and the mixture was reacted under reflux for 1 hour. After the reaction, water was distilled off under reduced pressure, and the obtained resol resin was dissolved in methanol to obtain Varnish A. Example 2 Into the reaction vessel described in Example 1, tall oil fatty acid polyglycerin ester with a hydroxyl value of 54 (acid value of 6.5,
Charge 300 g of iodine number 130 and color number (Herlige 6), heat to 90°C while passing nitrogen gas, and add 6 g of hexamethylene diisocyanate. 100
After being maintained at °C for 2.5 hours, the obtained modified product was phenolated in the same reaction as in Example 1, and then varnish B was obtained after resolization. Tall oil fatty acid trimethylolpropane ester with a hydroxyl value of 132 (acid value 12, iodine value 112, color number (Herlige) 6) was placed in the reaction vessel described in Example 1.
Charge 300 g, heat to 90°C while passing nitrogen gas, and add 21 g of xylene diisocyanate. After being maintained at 100° C. for 3 hours, the resulting reaction product was phenolated in the same manner as in Example 1, and then resolized to obtain Varnish C. Comparative Example 1 Tung oil (acid value 3.5,
Prepare 300g of iodine value 163, color number (Hellige) 6), mix with 900g of phenol, heat to 150℃ while passing nitrogen gas, and add para-toluenesulfonic acid.
Add 0.2g and react at 150°C for 2 hours. The obtained reaction product was subjected to the same reaction as in Example 1 to form a resol, and varnish D was obtained. Comparative Example 2 The same tall oil fatty acid pentaerythritol ester as in Example 1 was placed in the reaction vessel described in Example 1.
Charge 300g, mix with 900g of phenol, add 15g of boron trifluoride phenol complex (25%), and keep at 150°C for 4 hours while bubbling with nitrogen. The obtained reaction product was converted into a resol in the same manner as in Example 1 to obtain Varnish E. Example 4 Varnishes A to E prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were impregnated into laminated board paper so that the weight ratio of resol resin to paper was 1:1, and methanol was added at room temperature. After volatilization, 180Kg/cm ² , 150℃
A laminate was obtained by hot pressing under the following conditions. The obtained laminate according to the present invention has excellent electrical insulation properties and punching workability as shown in Table 1. 【table】

Claims (1)

[Claims] 1 To 100 parts by weight of tall oil fatty acid polyhydric alcohol ester having a hydroxyl value of 20 to 200, a compound of the general formula R-
(NCO) _o (wherein R represents a phenylene group, a diphenylmethane core group, or an alkylene group substituted with one or more groups selected from the group consisting of a phenyl group, an alkyl group, and a hydrogen group, n
represents a positive integer from 2 to 4. ) One or more compounds selected from the group of compounds shown in
After producing a modified tall oil fatty acid polyhydric alcohol ester by reacting 0.2 to 10 parts by weight, the modified tall oil fatty acid polyhydric alcohol ester is reacted with phenol in the presence of a Friedel-Crafts catalyst, and then in the presence of an alkaline catalyst. A method for producing an impregnating resin, which is characterized by reacting formalin therewith to form a resol.