Preparation And Application Of Alkoxylated Silicone Phosphate

Alkoxylated silicone phosphate, a kind of novel anionic surfactant , is prepared by the phosphation of a pendant hydroxyl group which is present on a silicone polymer. It provides excellent antistatic and lubricant properties, but not volatile and toxic. It has also a high degree of oxidative stability, even at elevated temperatures. These combination of properties makes the compound ideally suited for being used as plastic/fiber antistats and lubricants. It is also widely used as emulsifiers in industrial and personal care applications. At present, large-scale commercialization has not yet been developed in domestic market. The products reported in literature are generally 40-80% aqueous solution and can't be used in organic systems. Moreover, the species are not diversified and the inorganic salt content in the product is high. There is no report yet concerning the comparison of application performance between alkoxylated silicone phosphate and fatty alcohol ether phosphate. In this article, we produced alkoxylated silicone phosphate of high concentration via hydrosilylation, phosphorylation, neutralization and evaporation. We tried to find methods to control the processses. In addition, further exploration of the composition and structure on performance were conducted. Finally, we evaluated the application level of alkoxylated silicone phosphate by comparison of application performance between alkoxylated silicone phosphate and fatty alcohol ether phosphate.In this study, the three-step synthesis process conditions of the said polymer were studied. Firstly, a series of polyhydrosiloxanes were obtained with methylhydrosiloxane and D4, using sulfuric acid as catalyst. Secondly, hydrosilation reaction with allyl polyether and polyhydrosiloxane was used to make the silicone intermediates. Finally, the silicone phosphates were prepared by reacting the hydroxyl onto silicone intermediate with a suitable phosphating agent phosphorus pentoxide. Then via hydrolization, neutralization and evaporation, the final products were made into being. At above syntheses, the optimum conditions were probed and appreciate intermediates and products were obtained by adjusting the main influence factors of each reaction. In telomerization, the optimum reaction conditions were as follows: The molar ratio of MM and 202 is 0.8:1, the dosage of sulfuric acid catalyst was 2% by weight of the total material, rection temperature was 60℃, reaction time was 4h. In hydrosilylation, the suitable conditions were as follows: the feeding way was dropping allyl polyether into polyhydrosiloxane, the molar ratio of Si-H and C = C was 1:(1.05-1.1), the amount of catalyst (Pt) was 30ppm by weight of polyhydrosiloxane, reaction temperature was 95-110℃, reaction time was 3-4h. In phosphorylation and hydrolization, P2O5 was preferably added into polyether modified siloxane in batches. Water was added after phosphorylation. The molar ratio of hydroxyl, P2O5 and water was (1.8 ~ 2.1):1:(1 ~ 1.5). Reaction temperature was 70~80℃, reaction time was 3-4h. Hydrolysis temperature was 70~80℃, hydrolysis time was 2~3h. The phosphate present in the acid phosphatase of this invention was less than 2% by weight. After hydrolysis, the resultant was neutralized to pH=8.0 by 50% NaOH solution. Then toluene was added into the flask to lower water by distillation. Finally alkoxylated silicone phosphate of which solid content was up to 97% was got under 85℃and 0.09-0 .1 MPa vacuum in wiped film evaporator .In hydrosilation, we used IR quantitative analysis to trace the change of Si-H concentration; In addition, comparing IR spectrum of the reactant and that of resultant, the reactional progress and the characteristic peak of every products were defined. Moreover, the molecular structure of alkoxylated silicone phosphate was measured by 31P-NMR, the result showed that it contained a pendant ionizable phosphate group, it was a mixtue of mono, di and pyrophosphate ester.According to the testing of physical and applied characters of the surface of the products, we studied the influences of the composition, the structure of allyl polyether and the amount of silicone/polyether. The results indicated that with increasing of the content of monoester and the proportion of polyether, antistatic propertie of the product was getting better. With decreasing of the molecular weight of polyether, increasing of the content of diester and the weight ratio of silicone to polyether, smoothness was improved. On smoothness, the influence of the weight ratio of monoester to diester was far greater than the molecular weight of polyether. Compared with fatty alcohol ether phosphate , alkoxylated silicone phosphate has excellent overall properties, such as low surface tension, superior lubricant property, low foam, high degree of oxidative and non-polar solvent stability. The ability regulate the type of alkylene oxide and amount present in the silicone polymer results in a series of products ranging in water/oil solubility. The technology used to produce the said compounds is very flexible and allows us to prepare performance tailored molecules for specific applications.