JPH05310893A - Production of phenol resin - Google Patents

Abstract

PURPOSE:To obtain a phenol resin having flexibility and decreased brittleness. CONSTITUTION:A phenol compd. and a substd. xylene of the formula: RCH2-Ar- CH2R (wherein R is halogen, hydroxyl, or alkoxy; and Ar is phenylene) are condensed in the presence of a Friedel-Crafts catalyst or an acid catalyst to give a novolac-type oligomer, which is condensed with formaldehyde in the presence of a catalyst comprising an ankali or alkaline earth metal hydroxide at a pH of 8 or higher. Thus is obtd. a resol phenol resin having decreased brittleness. When the resin is foamed, the resulting foam exhibits a decreased surface friability, producing a decreased amt. of powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel resole type phenol resin having improved flexibility.

[0002]

2. Description of the Related Art A cured product of a phenol resin generally has a hard and brittle property. Therefore, this property becomes a problem when trying to develop the application of the phenol resin. In order to improve this brittleness, various additives or modifiers have been used. For example, it is known to use a plasticizer such as polyvinyl alcohol or phosphoric acid ester as an additive. Also known is a technique for improving the brittleness and imparting flexibility to the resin by modifying the resin itself by partially blending a phenol with alkylphenol, styrene, tung oil, etc. as a modifying agent. Is.

On the other hand, for the production of novolac-type phenol resin using xylylene glycol or the like instead of formaldehyde and its application examples, Japanese Patent Publication No. 47-15.
111, JP-A-63-238129, JP-A-1-9.
It is known from Japanese Patent No. 3551. Most of these novolac type resins are used as a solid, and hexamethylenetetramine is usually used as a curing agent during heat curing.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel method for producing a thermosetting phenolic resin which has flexibility and is improved in brittleness.

[0005]

The present invention is represented by phenols and RCH ₂ --Ar--CH ₂ R (wherein R represents a halogen, a hydroxyl group or an alkoxy group, and Ar represents a phenylene group). Substituted xylenes are condensed using a Friedel-Crafts catalyst or an acid catalyst to obtain a novolak type oligomer, and the novolak type oligomer and formaldehyde are catalyzed by an alkali metal hydroxide or an alkaline earth metal hydroxide. The method for producing a resole-type phenolic resin is characterized in that it is used for condensation at pH 8 or higher.

The phenols used in the present invention include:
Phenol, cresol, xylenol, resorcinol
And one or a mixture of two or more thereof. Also,
As the substituted xylenes represented by RCH ₂ —Ar—CH ₂ R (wherein R represents a halogen, a hydroxyl group or an alkoxy group, and Ar represents a phenylene group), R such as para-xylylene glycol is a hydroxyl group. And a compound in which R is halogen such as paradichloromethylbenzene, and a compound in which R is an alkoxy group such as paradimethoxymethylbenzene. The ratio of the phenols to the substituted xylenes used is 0.1 to 0.6 mol of the substituted xylenes, preferably 0.1 to 0.
It is 4 mol. If the amount of the substituted xylenes is less than 0.1 mol, the flexibility of the resin becomes insufficient, and if the amount of the substituted xylenes exceeds 0.6 mol, unreacted substituted xylenes remain, or the molecular weight becomes unacceptable when completely reacted. Becomes too large or gels.

The Friedel-Crafts catalyst or acid catalyst used in the condensation reaction between the phenols and the substituted xylenes is a Friedel-Crafts catalyst such as stannic chloride, zinc chloride or ferric chloride, or paratoluene. Examples thereof include acid catalysts such as sulfonic acid and benzenesulfonic acid. These catalysts may be used in an amount of about 0.01 to 1 times by weight that of phenols. And this reaction is usually 50
It is carried out at a temperature of ~ 200 ° C, preferably 70-150 ° C. The reaction time is preferably about 2 to 10 hours, though it depends on the reaction temperature, and it is desirable to set the reaction conditions so that it does not become too long. It is desirable to carry out this reaction until no substituted xylenes are observed.

A novolak type oligomer is produced by the above condensation reaction. Next, this is condensed with formaldehyde to obtain the phenol resin of the present invention. The novolak type oligomer produced by the above condensation reaction may be separated from the reaction mixture, but may be directly used for the next condensation reaction without separation. An alkali metal hydroxide or an alkaline earth metal hydroxide is added to the produced novolac type oligomer or a reaction mixture containing the same until pH 8 or more, and a condensation reaction is performed with formaldehyde such as formalin.

The amount of formaldehyde used in this reaction is in the range of 1.1 to 3.0 mol, preferably 1.2 to 2.0 mol, based on 1 mol of the phenol used in the first condensation reaction. Is good. When the amount of formaldehyde used is less than 1.1 mol, it becomes difficult to obtain a practical phenol resin due to lack of crosslinking groups, and when it exceeds 3.0 mol, unreacted formaldehyde increases and odor becomes severe. The catalyst used in this reaction is a hydroxide of an alkali metal such as sodium or potassium, or a hydroxide of an alkaline earth metal such as calcium or barium, which may be used in the form of an aqueous solution. The amount used is preferably 0.1 to 10 times by weight based on the phenol.

This condensation reaction is usually carried out in the temperature range of 40 to 100 ° C., preferably 50 to 90 ° C. so that the reaction time does not become extremely long. After completion of the reaction, the reaction mixture containing the produced phenol type phenol resin can be used as it is, depending on the intended use, and if necessary, subjected to treatments such as neutralization, washing, dehydration, etc. It is also possible to obtain a phenol type resin. Resonator of the present invention
The phenolic phenol resin can be used in the same applications as ordinary phenolic resins, and is particularly preferably used as a foaming resin.

[0011]

The phenolic resin obtained by the production method of the present invention has a xylylene group in the central skeleton of the resin and a crosslinkable methylol group in the phenol nucleus at the end. It is considered that flexibility was imparted while maintaining curability.

[0012]

EXAMPLES Examples of the present invention will be shown below. In addition, part and% show a weight part and weight%. Example 1 A flask was charged with 940 parts of phenol, 138 parts of p-xylylene glucose and 0.5 part of p-toluenesulfonic acid, and reflux was started at about 120 ° C., and reflux was continued for 2 hours to carry out a condensation reaction. I went. Gas chromatographic analysis confirmed the disappearance of p-xylylene glucose. Then, the reaction mixture was cooled to 40 ° C. or lower, and a 37% formalin solution was added to
Add 73 parts and add 20% sodium hydroxide solution to pH.
It was added until it reached 9.0, and a condensation reaction was carried out at a reaction temperature of 80 ° C. for 2 hours. Next, this reaction mixture was cooled to 40 ° C. or lower, neutralized by adding 50% p-toluenesulfonic acid aqueous solution until pH 7.0, and then dehydrated under reduced pressure to give a viscosity of 2100 cp (25 ° C.). Resole type pheno
A resin was obtained.

Obtained resole type phenol resin 10
0 parts, 5 parts of surfactant and CFC 113 as a foaming agent
20 parts are mixed and premixed, then 50 parts as a curing agent
% P-toluenesulfonic acid aqueous solution was mixed in 15 parts, and the mixture was stirred uniformly. This mixture was filled in a mold and foamed to obtain a molding board having a density of 0.060 g / cm ³ . The physical properties of this molding board are shown in Table 1.

Example 2 A flask was charged with 940 parts of phenol, 552 parts of p-xylylene glucose and 0.5 part of p-toluenesulfonic acid, and the reflux was started at about 120 ° C. and the reflux was continued for 3 hours. The condensation reaction was carried out. Gas chromatographic analysis confirmed the disappearance of p-xylylene glucose. Next, the reaction mixture is cooled to 40 ° C. or lower, and a 37% formalin solution is added to
Add 216 parts and pour 20% aqueous sodium hydroxide solution.
H was added until it reached 9.0, and a condensation reaction was carried out at a reaction temperature of 80 ° C. for 2 hours. Then, the reaction mixture was cooled to 40 ° C. or lower, neutralized by adding 50% p-toluenesulfonic acid aqueous solution until pH 7.0, and then dehydrated under reduced pressure to give a viscosity of 6000 cp (25 ° C.). Resole type pheno
A resin was obtained. A density of 0.063 g / c was obtained in the same manner as in Example 1 except that the obtained resole-type phenol resin was used.
A molding board of m ³ was obtained. The physical properties of this molding board are shown in Table 1.
Shown in.

Comparative Example 1 A flask was charged with 940 parts of phenol and 1216 parts of 37% formalin solution, 20% aqueous sodium hydroxide solution was added until the pH reached 9.0, and the mixture was condensed at a reaction temperature of 80 ° C. for 4 hours. Reacted. The reaction mixture is then brought to 40 ° C.
After cooling to below and neutralizing by adding 50% p-toluenesulfonic acid aqueous solution until pH 7.0, dehydration is performed under reduced pressure to obtain a resole type phenol resin having a viscosity of 2300 cp (25 ° C.). Got A density of 0.057 g was obtained in the same manner as in Example 1 except that the obtained resole phenol resin was used.
A molding board of / cm ³ was obtained. The physical properties of this molding board are shown in Table 1.

[0016]

[Table 1]

(Measuring Method of Powdering Ratio) Four cubes each having a side of 2 cm were cut out from the molding board, placed in a cylindrical container, sealed, shaken for a certain period of time with a small shaker, and then powdered. Measure the amount and calculate the ratio.

[0018]

According to the manufacturing method of the present invention, it is possible to obtain a resole type phenolic resin having improved brittleness. When this is used as a resin for foams, the brittleness of the surface is improved and the amount of powdering can be reduced.

Claims (1)

[Claims] 1. A phenol and RCH ₂ —Ar—CH ₂ R
(Wherein R represents a halogen, a hydroxyl group or an alkoxy group and Ar represents a phenylene group) is condensed with a Friedel-Crafts catalyst or an acid catalyst to obtain a novolak type oligomer. Using a novolac type oligomer and formaldehyde as a catalyst with an alkali metal hydroxide or an alkaline earth metal hydroxide as a catalyst,
A method for producing a resole-type phenolic resin, which comprises condensing at 8 or more.