Thermosetting organosiloxane composition

• US 5,017,654 A
• Filed: 06/28/1989
• Issued: 05/21/1991
• Est. Priority Date: 06/30/1988
• Status: Expired due to Term

• Current Assignee: Toray Silicone Co Ltd (Toray Industries Incorporated)
• Original Assignee: Toray Silicone Co Ltd (Toray Industries Incorporated)
• Inventors: Saruyama, Toshio, Togashi, Atsushi
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US07/372,579
• Time in Patent Office: 692 Days
• Field of Search: 528/15, 525/100, 525/106, 525/477, 525/478
• US Class Current: 525/100
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/16 to hydroxyl groups
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/24 halogen-containing groups
• CPC Class Codes: C08G 77/44 containing only polysiloxane sequences
• CPC Class Codes: C08G 77/70 Siloxanes defined by use of the MDTQ nomenclature
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: C08L 2666/52 Metal-containing compounds
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

The combination of a microencapsulated hydrosilylation catalyst selected from the group consisting of metals from the platinum group of the periodic table and compounds of these metals and a known inhibitor for this type of catalyst impart excellent storage stability to organosiloxane compositions that cure by a hydrosilation reaction while enabling these compositions to rapidly cure at temperatures above the softening temperature of the thermoplastic resin used to encapsulate the hydrosilylation catalyst. The curing rate of the composition is faster relative to compositions containing the microencapsulated catalyst without the catalyst inhibitor.

Claims

1. In a thermosetting organosiloxane composition comprising

(A) an organopolysiloxane having at least two silicon-bonded alkenyl groups in each molecule and represented by the average unit formula

View Dependent Claims (2, 3, 4)

2. A thermosetting organopolysiloxane composition according to claim 1 in which the thermoplastic resin is selected from the group consisting of polystyrene, polymethyl methacrylate, silicone resins and polysilanes, the hydrosilylation-reaction catalyst is a metal from the platinum group of the periodic table or a compound of said metal and is present at a concentration of from 0.000001 to 0.1 part by weight, based on platinum, per 100 parts by weight of said organopolysiloxane, the boiling point of said inhibiting compound is at least 80°

C., the concentration of said inhibiting compound is from 0.00001 to 5 parts by weight per 100 parts of said organopolysiloxane, and R represents at least one member selected from the group consisting of alkyl, alkenyl, aryl, and halogen-containing alkyl radicals,

3. Thermosetting organopolysiloxane composition of claim 2 wherein the hydrosilylation catalyst is a platinum/alkenylsiloxane complex, R is at least one member selected from the group consisting of methyl, phenyl and 3,3,3,-trifluoropropyl, said organopolysiloxane is a polydiorganosiloxane, and the concentration of said hydrosilylation reaction catalyst is equivalent to from 0.00005 to 0.01 part by weight of platinum per 100 parts by weight of said organopolysiloxane.

4. A thermosetting composition according to claim 1 where said disiloxanes and cyclotetrasiloxanes containing at least one bonding unit in which an alkenyl radical is bonded to each of two silicone atoms joined through an oxygen atom bridge are selected from the group consisting of 1,3-divinyltetramethyldisiloxane, 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane, and 1,3-divinyl-1,3-diphenyldimethyldisiloxane.