Preparation method of phenolic resin for producing epoxy resin

Abstract

The invention discloses a method for preparing a phenolic resin. The method for preparing a phenolic resin of the present invention comprises: 1. The mass percentage is 55% to 65% of the total amount of phenol, 20% to 30% formaldehyde, and 20% of the weight of phenol %~50% of aromatic hydrocarbons and 0.2%~0.5% of oxalic acid are put into the reactor according to the ratio, and heated slowly to make it rise to the reflux temperature of 85°C-100°C; maintain it for 1.5-2.0 hours; 2. Cool to 80°C Below, add 0.4% to 0.6% of the total amount of hydrochloric acid with a mass concentration of 37%, reheat to the reflux temperature of 85°C-100°C, and maintain for 2.0-4.0 hours; 3. Cool to below 70°C, add the total amount of feed 0.2%~0.6% of the alkali solution with a mass concentration of 30% is neutralized until pH = 6.7-7.0; 4. Heating and reflux for water separation until the temperature exceeds 110°C, and the water separation ends; 5. Removal of aromatic hydrocarbons and phenol under reduced pressure , to the temperature ≥ 150 ° C, vacuum ≤ -0.9MPa, you can get the desired phenolic resin.

Description

technical field [0001] The invention relates to a preparation method of phenolic resin, especially a preparation method suitable for synthesizing epoxy resin, having lower phenol-containing wastewater and less phenol-containing wastewater. Background technique [0002] Phenolic resin is a kind of resin produced by condensation polymerization of phenol and formaldehyde in a certain proportion under the action of acid or alkali catalysis. Different proportions and different catalysts can be used to obtain thermoplastic or thermosetting phenolic resins. Phenolic resin has a wide range of uses, and the manufacture of epoxy resin is a very important use. The production method of phenolic resin used to prepare epoxy resin is generally: the proportion of phenol and formaldehyde is greater than one, using acid as a catalyst, and synthesizing lower molecular weight novolac resin under certain reaction conditions. In the synthesis process, due to the control of the molecular weight ...

AI Technical Summary

Problems solved by technology

In the synthesis process, due to the control of the molecular weight and molecular structure, water with the same weight as phenol is generally added. After the reaction is completed, the added water and excess phenol are removed together to obtain phenolic resin suitable for epoxy resins. Resin, in this process, there will be a large amount of waste water with high phenol content, and the phenol content is generally 4% to more than 10%. Generally, these waste water must be effectively treated in order to make phenol recycling and waste water discharge Up to the standard, a large amount of high-phenolic wastewater increases the difficulty of treatment and increases the cost of production