Silicone sealants having reduced color

• US 4,906,719 A
• Filed: 11/28/1988
• Issued: 03/06/1990
• Est. Priority Date: 11/28/1988
• Status: Expired due to Term

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: Dow, Inc.
• Inventors: Chu, Hsien-Kun, Klosowski, Jerome M., Lower, Loren D., Kamis, Russell P.
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US07/276,977
• Time in Patent Office: 463 Days
• Field of Search: 528/17, 528/23, 528/18
• US Class Current: 528/17
• CPC Class Codes: C08K 5/37 Thiols
• CPC Class Codes: C08K 5/5406 containing elements other than oxygen or nitrogen
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C08L 83/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C08L83/10 takes precedence
• CPC Class Codes: C09K 3/1018 Macromolecular compounds having one or more carbon-to-silicon linkages

Abstract

A chelated titanium catalyst can be improved by the addition of an additive selected from the group consisting of organomercaptan of the formula RSH, where R is a hydrocarbon radical containing from 3 to 12 carbon atoms, and mercapto containing silane of the formula HSR'"'"'SiX₃, where R'"'"' is a divalent hydrocarbon having from 1 to 8 carbon atoms and X is alkoxy radical having 1 to 6 carbon atoms. The improved composition has a reduced tendency to develop color upon storage. The improved composition is particularly useful in a silicone composition comprising a hydroxyl endblocked polydiorganosiloxane and an alkoxysilane or mixture of alkoxysilanes, or in a silicone composition comprising an alkoxy endblocked polydiorganosiloxane.

Claims

1. In an elastometric composition comprising (i) a hydroxyl endblocked polydiorganosiloxane and a silane or mixture of silanes having an average of from 2.01 to 4 inclusive alkoxy radicals, or an alkoxy endblocked polydiorganosiloxane, and (ii) a chelated titanium catalyst, wherein the improvement comprises the addition of an additive selected from the group consisting of organomercaptan of the formula RSH, where R is a hydrocarbon radical containing from 3 to 12 carbon atoms, and mercapto containing silane of the formula HSR'"'"'SiX₃, where R'"'"' is a divalent hydrocarbon having from 1 to 8 carbon atoms and X is alkoxy radical having 1 to 6 carbon atoms.

2. The composition of claim 1 in which the additive is an organomercaptan of the formula RSH where R is a hydrocarbon radical containing from 3 to 12 carbon atoms.

3. The composition of claim 2 in which the organomercaptan is dodecylmercaptan.

4. The composition of claim 1 in which the additive is a mercapto containing silane of the formula HSR'"'"'SiX₃, where R'"'"' is a divalent hydrocarbon having from 1 to 8 carbon atoms and X is alkoxy radical having 1 to 6 carbon atoms.

5. The composition of claim 4 in which the mercapto containing silane is mercaptopropyltrimethoxysilane.