The Solvent-free Technology Of Polyether-Modified Siloxane Leveling Agent

Polyether-modified siloxane levelling agent was synthesized by hydrogenation of polyhydrosiloxane and allyl-polyether.Because of relatively high molecular weight of raw materials,it is difficult to carry out the hydrogenation reaction completely.In order to achieve the reaction conversion ratio to more than 95%,the xylene or other solvents must be used in reaction system.This traditional technology using solvent has disadvantages of low productivity,high cost and high safety risk.So,in the present work,we seek to synthesize polyether-modified siloxane levelling agent in absence of solvent.In order to develop the solvent-free technology of polyether-modified siloxane leveling agent,we did following works and obtained some good results as follows:? Chloroplatinic acid was mixed with vinyl-trimethoxy silane,then this complex was loaded onto the MQ resin.We prepared the MQ-Pt catalyst and measured Pt content and thermal stability of this catalyst.? The compositions of the raw materials are as follows:the molecular weight of polyhydrosiloxane is 3000,the hydrogen content of polyhydrosiloxane is 0.2%,the molecular weight of allyl-polyethe is 2000.The effetcs of reaction conditions including on initial temperature,reaction temperature,catalyst dosage and reaction time for the hydrogenation of polyhydrosiloxane and allyl-polyether in absence of solvent were studied and discussed.Finally,the optimal reaction process conditions are obtained as follows:the initial reaction temperature is 70?,the amount of MQ-Pt catalyst is 6ppm,the reaction temperature is 100?,and the reaction time is 7 hours.Under this condition of reaction,the conversion rate of hydrosilylation was 96%.? The molecular weight range of allyl-polyether was expanded to 400-2000,the molecular weight of polyhydrosiloxane was expanded to 134-6000 and the hydrogen content was expanded to 0.1%-1.2%.Experimental results of crossover trials showed that using the above raw materials,all reaction conversion rates through the solvent-free technology could reach to 97%.?The conversion ratios of hydrosilylation reactions using either the MQ-Pt catalyst or the Karstedt catalyst in the solvent-free technology were compared.The results showed that only in the case of MQ-Pt catalyst,higher reaction conversion rate of the hydrosilylation reaction in the solvent-free technology is obtained.? The polyether-modified siloxane prepared by solvent-free technology were to compared with the polyether-modified siloxane by solvent technology,the results showed that the viscosity,refractive index and surface tension of polyether-modified siloxane obtained from two technology were the same.? The static surface tension,dynamic surface tension,long and short wave DOI,smooth of polyether-modified siloxanes obtained from the two differnt technology respectively were compared in the hydroxyl-acrylic lacquer.The results show that their leveling performances are the same.?The scale-up production of the polyether-modified siloxane prepared by solvent-free technology were conducted using polyhydrosiloxane of 3000 molecular weight and 0.2%hydrogen content,allyl-polyethe of 2000 molecular weight as raw materials in production,the quality and properties of the product obtained is the same as the in the test.Finally,the research objctive was sucessfully achived,that is the product by solvent-free technology is the same as product by solvent technology.The new production process is simple,safe and environment friendly,the utilization of raw materials is 100%and no "three wastes".