The invention provides a preparation method of methoxy hydroxyl-terminated
silicone oil, which is mainly applied to a
structure control agent in the field of
silicone rubber, and comprises the following steps: by taking
hydrolysate (a mixture of dimethyl cyclosiloxane and hydroxyl-terminated
polydimethylsiloxane linear body) as a
raw material, adding a basic catalyst under the protection of
inert gas, adding an end-capping
reagent a: a
methanol solution, and reacting at the temperature of 60-80 DEG C for 1-2 hours; the preparation method comprises the following steps: adding an end-capping
reagent b, namely water or alkoxy
silane, into a reaction kettle, carrying out
reflux reaction at 50-80 DEG C, adding an end-capping
reagent b, namely water or alkoxy
silane after the
viscosity of the material is stable, reacting for 0.5 hour, filtering to remove the catalyst, and removing the catalyst to obtain the hydroxyl methoxy-terminated
polydimethylsiloxane. The hydroxyl-methoxyl mixed end-capped
polydimethylsiloxane prepared by the method has the advantages of high
flash point, good safety performance and strong
tear resistance, the molecular weight of the hydroxyl-methoxyl mixed end-capped polydimethylsiloxane is several times larger than that of dimethyldimethoxysilane, but the content of active groups of the hydroxyl-methoxyl mixed end-capped polydimethylsiloxane is equivalent to that of hydroxyl
silicone oil. Therefore, redundant water molecules are not generated in the anti-structuring process, so that the
structural stability of the
sizing material is improved.