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US 11,028,230 B1Granted
Method for condensation polymerization of hydroxyl-terminated polydiorganosiloxanes
AssigneesDow Silicones Corporation, Dow Global Technologies LLC
InventorsMatthew Belowich, Mark Rickard, Vladimir Pushkarev, Shaungbing Han, Evelyn Auyeung, John Roberts, Thomas Peterson
Life of this patent
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Abstract
A method for making long chain hydroxyl terminated polydiorganosiloxanes with low cyclics content via condensation polymerization employs a trifluoromethane sulfonate compound catalyst. The trifluoromethane sulfonate may be complexed with a multidentate ligand.
Claims16
A method for polymerizing polydiorganosiloxanes comprising:
- 1) heating, at a temperature of 50° C. to 200° C., a reaction mixture prepared by mixing starting materials comprising
- A) a polydiorganosiloxane of unit formula [(HO)R2SiO1/2]2(R2SiO2/2)n, where subscript n is 0 to 2000, and each R is an independently selected monovalent hydrocarbon group of 1 to 18 carbon atoms;
- and
- B) 10 ppm to 500 ppm, based on weight of starting material A), of a trifluoromethane sulfonate compound selected from the group consisting of
- B-1) aluminum(III) trifluoromethanesulfonate,
- B-2) bismuth(III) trifluoromethane sulfonate,
- B-3) gallium(III) trifluoromethane sulfonate,
- B-5) indium(III) trifluoromethane sulfonate,
- B-6) scandium(III) trifluoromethane sulfonate, and
- B-7) dicyclohexylboron trifluoromethanesulfonate;
- 2) quenching the reaction mixture;
- and
- 3) recovering a product from the reaction mixture, where the product has unit formula [(HO)R2SiO1/2]2(R2SiO2/2)m, where m>n.
10 more elements
A method for polymerizing polydiorganosiloxanes comprising:
- 1) heating, at a temperature of 50° C. to 200° C., a reaction mixture prepared by mixing starting materials comprising:
- A) a polydiorganosiloxane of unit formula [(HO)R2SiO1/2]2(R2SiO2/2)n, where subscript n is 0 to 2000, and each R is an independently selected monovalent hydrocarbon group of 1 to 18 carbon atoms;
- and
- B) 10 ppm to 500 ppm, based on weight of starting material A), of iron(III) trifluoromethanesulfonate;
- 2) quenching the reaction mixture by adding an amine and cooling the reaction mixture to a temperature less than 50° C.;
- and
- 3) recovering a product from the reaction mixture, where the product has unit formula [(HO)R2SiO1/2]2(R2SiO2/2)m, where m>n.
4 more elements
Dependencies are inferred from the claim text.