Production method of high purity terminal hydroxy phenyl ladder polysiloxane prepolymer and production method null of high purity terminal hydroxy phenyl ladder

摘要

PURPOSE:To obtain the subject polysiloxane having a specific structural formula and low content of sodium, etc., by mixing phenyltrichlorosilane with a com pound having a specific formula, dissolving the mixture in an organic solvent, adding extrapure water to hydrolyze the compound and finally washing with extrapure water. CONSTITUTION:The objective polysiloxane expressed by formula II (R1 and R2 are alkenyl, phenyl, etc.; n is 570-1,600; m and l satisfy the formulas 2n=m+n and l/m+l=0.02), containing =1ppm of Na, K, Fe, Cu, Pb and Cl and =1ppb of U and Th, formable to a thick film and giving a cured product having excellent crack resistance and heat-resistance can be produced by mixing phenyltrichlorosilane with =2mol% of a compound of formula I (X is H, methyl etc.; p is 0-10), dissolving the mixture in an organic solvent at a concentration of 0.05-0.45g/ml, dropping 3-30mol of extrapure water to 1mol of the above mixture, hydrolyzing the mixture and washing the product with extrapure water.