Name: SiSiB® PC7970
Brand: Nanjing SiSiB Silicones Co., Ltd.

Technical Data

CAS No.	17865-07-5
EINECS No.:	241-816-9
Formula	C₉H₁₆O₆Si
Molecular Weight	248.31
Boiling Point	236°C [760mmHg]
Flash Point	81°C

Color and Appearance	Colorless or yellowish clear liquid
Density _25/25_°C	1.112
Refractive Index_[2₀_°C]	1.430
Active Content	98.0%

Application

SiSiB® PC7970 propyltriacetoxysilane, PTAS silane, is used as a raw material (crosslinker) for acetoxy crosslinking RTV-1 sealants.
Acetoxy silanes are more reactive than alkoxy silanes. Acetoxy silanes are frequently used as one-component mixtures to make RTV-1 silicone sealants. These mixtures have an excess of multi-functional acetoxy silane added to silanol-terminated PDMS, which results in a PDMS chain with acetoxy groups at the ends.

When this compound is exposed to moisture some acetoxy groups are hydrolyzed and self-condense or react with other acetoxy and rapid crosslinking takes place. Acetic acid formation is one of the driving forces of this reaction.