# US 11,028,230 B1 · Method for condensation polymerization of hydroxyl-terminated polydiorganosiloxanes

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- Number: US 11,028,230 B1
- Document ID: US11028230B1
- Status: Granted
- Kind: B1
- Application number: 17/259,720
- Filed: 2019-07-03
- Published: 2021-06-03
- Granted: 2021-06-08
- Earliest claimed: 2018-08-24
- Assignees: Dow Silicones Corporation; Dow Global Technologies LLC
- Applicants: Dow Silicones Corporation; Dow Global Technologies LLC
- Inventors: Matthew Belowich; Mark Rickard; Vladimir Pushkarev; Shaungbing Han; Evelyn Auyeung; John Roberts; Thomas Peterson
- Web page: https://patentgrep.com/patent/US11028230B1

## CPC

- C08G 77/08: characterised by the catalysts used
- C08G 77/16: to hydroxy groups
- C08G 77/10: Equilibration processes
- C08L 83/04: Polysiloxanes
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

The method of claim 1, where each R is independently selected from the group consisting of alkyl, alkenyl, and aryl.

### Claim 3 (depends on 1)

The method of claim 1, where subscript n is 10 to 150.

### Claim 4 (depends on 1)

The method of claim 1, where the trifluoromethanesulfonate compound is present in an amount of 10 ppm to 50 ppm.

### Claim 5 (depends on 1)

The method of claim 1, where the trifluoromethanesulfonate compound is selected from the group consisting of B-2) bismuth(III) trifluoromethane sulfonate, B-3) gallium(III) trifluoromethane sulfonate, and B-4) iron(III) trifluoromethanesulfonate.

### Claim 6 (depends on 1)

The method of claim 1, where the trifluoromethanesulfonate compound is selected from the group consisting of B-1) aluminum (III) trifluoromethane sulfonate, B-5) indium(III) trifluoromethane sulfonate, and B-6) scandium(III) trifluoromethane sulfonate.

### Claim 7 (depends on 6)

The method of claim 6, further comprising: mixing B) the trifluoromethanesulfonate compound and C) a chelating ligand for the metal trifluoromethanesulfonate before step 1).

### Claim 8 (depends on 7)

The method of claim 7, where C) has the general formula:
where each R2 and each R1 are an independently selected alkyl groups of 1 to 8 carbon atoms.

### Claim 9 (depends on 1)

The method of claim 1, where starting material D), a solvent, is present.

### Claim 10 (depends on 9)

The method of claim 9, where the solvent is selected from the group consisting of aprotic solvents and trimethylsiloxy-terminated polydimethylsiloxanes.

### Claim 11 (depends on 10)

The method of claim 10, where the solvent is selected from the group consisting of tetrahydrofuran, toluene and dichloromethane.

### Claim 12 (depends on 1)

The method of claim 1, where step 1) is performed by heating at a temperature of 80° C. to 105° C. for 30 seconds to 2 hours.

### Claim 13 (depends on 1)

The method of claim 1, where the method further comprises removing water during and/or after step 1).

### Claim 14 (depends on 1)

The method of claim 1, where step 2) is performed by adding an amine and cooling the reaction mixture to a temperature less than 50° C.

### Claim 15 (depends on 1)

The method of claim 1, where step 3) is performed by a method comprising filtering, stripping and/or distilling the reaction mixture.

### Claim 16

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.