The invention discloses a fluorosiloxane
copolymer and a preparing method thereof. The method includes the following steps that 0.1-50 parts of methylphenyldichlorosilane or diphenyl cyclosiloxane, 45-99.8 parts of 1,3,5-
tris(3,3,3-trifluoropropyl)methylcyclotrisiloxane and 0.1-5 parts of polymethylphenylsiloxane are sequentially added into a reactor and dried under the heating condition of 60- 90 DEG C, and water and CO2 in a reactant are removed, wherein the total number of the methylphenyldichlorosilane or diphenyl cyclosiloxane, the 1,3,5-
tris(3,3,3-trifluoropropyl)methylcyclotrisiloxane and the polymethylphenylsiloxane are 100 parts; an initiator and an
accelerant are added, the use quantity of the initiator accounts for 0.001-1% the
mass of the reactant, the use quantity of the
accelerant accounts for 0.01-1% the
mass of the reactant, at the temperature of 90-200 EDG C, preferentially 130-150 DEG C, stirring reaction is carried out until a shaft is wrapped in a N2
atmosphere under a normal-pressure condition, balanced reaction continues being carried out for 2-3 h, and
raw rubber is manufactured; an acidoid
neutralization initiator is added into the
raw rubber manufactured in the step (2), extraction or high-vacuum
processing is carried out on the neutralized
raw rubber, and low-molecular matter is removed.
Heat resistance of the fluorosiloxane
copolymer is improved by about 80 DEG C compared with fluorosiloxane raw rubber with 100% of methyl trifluoropropyl.