The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 03, 1998
Filed:
May. 28, 1997
Aref Ben Ahmed Jallouli, Midland, MI (US);
John Carlton Saam, Midland, MI (US);
Dow Corning Corporation, Midland, MI (US);
Abstract
Method of making polysiloxanes by ring opening polymerization of dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane (D.sub.3), and cyclosiloxanes such as 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl) cyclotrisiloxane (F.sub.3) or 1,3,5,7-tetramethyl-1,3,5,7-tetrakis(3',3',3'-trifluoropropyl) cyclotetras iloxane (F.sub.4) in an acid-free system using electrophillic initiators. The reaction mixture is formed under anhydrous conditions and contains (i) the cyclosiloxanes, (ii) a Lewis base such as 2,6-di-tert-butylpyridine which serves as a co-catalyst and an acid scavenger, and optionally (iii) a salt of a strong acid such as tetrabutylammonium trifluoromethane sulfonate. The anhydrous mixture is contacted with a silyl ester of a strong acid such as triflic acid. The anhydrous reaction mixture is agitated at room temperature until a polysiloxane is formed. Polymerization can be initiated practically immediately after introduction of the cyclosiloxanes, by first adding the Lewis base to the silyl ester, and allowing the Lewis base and the silyl ester to interact.