Study On Preparation Of Hydrogenated MQ Silicone Resin By Water Glass Organicization

Yuntianhua International Chemical Co., Ltd., Sanhuan branch Co. has a installation which produces30000tons cryolite from by-product fluosilicic acid of the phosphate fertilizer per year. Large amount of silica gel would be generated in the production process. The main component of the silica gel is silicon dioxide, and it is largely contained. It is a good raw material for silicon production. Currently, the technology of Comprehensive utilization of by-product silica gel is silicate preparation and white carbon black production. Further utilization of silica gel is limited, and the added value is not high. MQ silicone resin is a kind of high value-added organic silicon polysiloxane. It is composed of monofunctional siloxane chain (M) and tetrafunctional siloxane chain (Q). The property of MQ silicone resin is among inorganic polymer and organic polymer. It has good properties such as temperature resistance, cohesiveness, weathering resistance, chemical resistance, mechanical, film formation and so on. Therefore, MQ silicone resin has a great application value in industry. It is mainly used as organic silicon pressure sensitive adhesive filler and tackifier, silicone rubber reinforcing filler. Hydrogen-Containing MQ silicone resin as a kind of modified MQ silicone resin, the compatibility between MQ silicone resin and organic polymer or pigment was enhanced because of the Si-H was brought in. This thesis introduced the method of producing low modulus water glass at first, then preparing two-phase Hydrogen-Containing MQ silicone resin with the raw material of by-product fluosilicic acid of the phosphate fertilizer.Firstly, the preparation process of MQ silicone resin was studied. The synthetic process is as follows:(1) water glass was hydrolyzed under the acid environment with the presence of isopropanol. Then run the action of hydrolytic polycondensation with MM and isopropanol mix solution added in. several minutes later, extraction agent was added in. MQ silicone resin extraction solution was prepared by backflow condensation.(2)After washing, drying, filtration and vacuum distillation, the extracting solution of hydrogen MQ silicone resin turned into white powder product. The structure of the product was confirmed to be Hydrogen-Containing MQ silicone resin by IR. Using single factor experiment, orthogonal experiment and regression response surface analysis method for the influence factors of the preparation process of Hydrogen-Containing MQ silicone resin are studied, the result is it the follows:(1) Under the condition of the appropriate ratio M/Q=0.8, MQ silicone resin which had lower M/Q ratio, narrow molecular weight distribution and good heat resistance can be produced by this method;(2) The optimal conditions of MQ silicone resin production:59g of water glass with10.5%concentration, raw material ratio M/Q=0.8,13.6mL of HC1catalyze, the temperature of hydrolyticpolycondensation was46℃, the duration of hydrolyticpolycondensation was39min,20mL of isopropanol,25mL of toluene, the duration ofcountercurrent extraction with reflux was3-4h, the temperature of countercurrent extraction with reflux was70～80℃Under the optimal conditions, the highest yield rate of MQ silicone resin was43.88%. FTIR and NMR indicated that Synthetic product was MQ silicone resin; Though GPC, the number-average molecular weight was2220, the distribution coefficient was2.41;The M/Q ratio of product was0.72,the hydroxyl content was4.2%.Therefor,Synthetic MQ silicone resin could be applied to the silicone rubber and silicone pressure sensitive adhesive for reinforcing agent.Secondly,the preparation process of Hydrogen-Containing MQ silicone resin which is the target product of this project was studied.The synthesis process is in the following:(1) Run the reaction of hydrolytic polycondensation between MQ silicone resin and Tetramethyldisiloxane under acid environment to obtain toluene solution of hydrogen MQ silicone resin;(2) After washing, drying, filtration and vacuum distillation,the toluene solution of hydrogen MQ silicone resin turned into white powder product. The structure of the product was confirmed to be Hydrogen-Containing MQ silicone resin by IR.Using single factor experiment, orthogonal experiment and regression response surface analysis method for the influence factors of the preparation process of Hydrogen-Containing MQ silicone resin are studied, the optimum process conditions are as follows:8g of MQ silicone resin which contains4.2%hydroxyl,1.52g of sealing agent,20ml of toluene,0.25g of catalyst, the reaction temperature is62℃, the reaction durations9.87h.Under this optimum condition, the product with the content of0.1830%hydrogen was gained. It was confirmed as Hydrogen-Containing MQ silicone resin through IR and NMR; The M/Q ratioof the product is0.79, content of hydroxyl is1.3%. It was proven to be up to the mustard with reinforcing agent of silicone rubber and silicone pressure sensitive adhesive.