Method for preparing low-molecular-weight hydroxyl silicone oil

Abstract

The invention relates to a method for preparing low-molecular-weight hydroxyl silicone oil, which comprises the following steps: adopting hexamethyl-cyclotrisiloxane as a raw material and perfluoro-sulfonate ion-exchange resin as a catalyst; reacting the materials at a temperature of between 50 and 70 DEG C for 1 to 2 hours in the presence of water and a solvent; filtering the mixture to remove the perfluoro-sulfonate ion-exchange resin; and vacuumizing the mixture at a temperature of between 20 and 80 DEG C and under a pressure of between 10 and 20 KPa and extracting out the solvent to obtain the low-molecular-weight hydroxyl silicone oil. The general formula of the hexamethyl-cyclotrisiloxane is (R2SiO)3, wherein R is Me; the dosage of the perfluoro-sulfonate ion-exchange resin is 1 to 10 percent of the weight of the hexamethyl-cyclotrisiloxane; the solvent is methanol, acetone or tetrahydrofuran; the molar ratio of the dosage of the water to the dosage of the hexamethyl-cyclotrisiloxane is 1.1-1.2:1; and the molar ratio of the dosage of the solvent to the dosage of the hexamethyl-cyclotrisiloxane is 1-5:1. The low-molecular-weight hydroxyl silicone oil is used as a silicon rubber structural control agent, an isolation paper coating, a mold releasing agent and room temperature silicon sulfide rubber; and the process is simple, the degree of polymerization is easy to control, and no environmental pollution exists.

Description

technical field [0001] The invention relates to a preparation method for synthesizing low-molecular-weight hydroxyl silicone oil with hexamethylcyclotrisiloxane as raw material, perfluorosulfonic acid ion exchange resin as catalyst, and under the action of equivalent water and solvent. Background technique [0002] The use of low molecular weight hydroxy silicone oil includes: as an intermediate to synthesize high molecular weight polymer; as an additive to prepare heat vulcanized silicone rubber, room temperature vulcanized silicone rubber and organic rubber, etc. Low molecular weight hydroxy silicone oil is widely used as a treatment agent in the silicone industry. For example, in the process of processing silicone rubber, the rubber compound mixed with silicone rubber raw rubber and high-reinforcement hydrophilic silica will gradually harden during storage, reduce plasticity, and gradually lose re-milling and molding processing and other process performance. The reason ...

AI Technical Summary

Problems solved by technology

This method has a high yield, but because the methanol solvent cannot be recycled, the hydrolysis solution generally needs to be discarded, which is easy to cause environmental pollution

In US3853932, hexamethylcyclotrisiloxane is introduc