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 introduced in the presence of acetone and water under the action of acidic montmorillonite catalyst to generate low molecular weight hydroxyl silicone oil with a polymerization degree of 3 to 10. The reaction of this method is extremely incomplete