Polysiloxane oils contg. cyclic di:organo-polysiloxane(s) - to improve heat stability, and used as heat transfer media, lubricants for (in)organic fibres and for prepn. of greases hydraulic oils, etc.

摘要

Silicone oils consists of (A) diorgano-polysiloxanes with triorgano-siloxy ends gps., and contain (B) 1-10(2-7) wt.% cyclic diorgano-polysiloxanes with =7 (pref. 8-9) diorgano-siloxane gps. per molecule. Pref. the diorgano-siloxane units in (B) are the same in type and amt. as those in (A). (B) is of formula (R2SbO)p, (in which R is an alkyl, alkenyl or aryl gp., pref. =50-(80)% being methyl and the remainder phenyl; p is =7, pref. 8-9). Splitting and reforming of siloxane bonds in (A) by heat, esp. in presence of residual traces of catalyst, is reduced by addn. of (B), giving oils with improved heat stability and resistance to viscosity changes.