Process for preparing elastomers

US4013611A · kind A · utility

Assignee

• Wacker Chemie AG · DE

Inventors

• Wolfgang Hechtl · Burghausen, DE
• Ernst Wohlfarth
• Alois Strasser · Burghausen, DE

Key dates

• Filing date: Jun 23, 1975
• Grant date: Mar 22, 1977
• Expiry date: Jun 23, 1995

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G77/70
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

An improved process for preparing compositions capable of being converted into elastomers containing (A) triorganosiloxy-terminated diorganopolysiloxanes having at least one vinyl group in each terminal unit, (B) triorganosiloxy-terminated organopolysiloxanes containing organohydrogensiloxane units and diorganosiloxane units, (C) fillers which are hydrophobic or are capable of being rendered hydrophobic and having a surface area of at least 50 m.sup.2 /g and (D) catalysts which promote the addition of SiH groups to vinyl groups which comprises mixing organopolysiloxanes (B) containing organohydrogensiloxane (SiH) units with at least 75 percent by weight of the fillers (C) having a surface area of at least 50 m.sup.2 /g before mixing with the organopolysiloxanes (A) having triorganosiloxy-terminal units with at least one vinyl group in each terminal unit.