Devolatization of highly viscous silicone fluids in the short path evaporator

Patent metadata

Field	Value
Publication number	US-11384206-B2
Application number	US-201616321566-A
Country	US
Kind code	B2
Filing date	Aug 4, 2016
Priority date	Aug 4, 2016
Publication date	Jul 12, 2022
Grant date	Jul 12, 2022

Abstract

Volatile siloxanes, particularly those of a cyclic nature, are removed from high viscosity silicone polymers and high viscosity silicone compositions by evaporation in a short path evaporator.

First claim

The invention claimed is:

1. A method for removing volatile constituents from a high-viscosity silicone polymer having a viscosity of 1000 to 20,000 Pa*s or a silicone composition having a viscosity of 100 to 20,000 Pa*s, comprising:
introducing the high viscosity silicone polymer or the silicone composition into a short path evaporator which comprises a vertically disposed cylinder having a heating jacket which heats the inner wall of the cylinder; a rotor, and an internal condenser, wherein mounted on the rotor are wiper elements and conveying elements, which distribute the silicone polymers or silicone composition in the form of a thin layer on the heated inner wall and convey the silicone polymers or silicone composition toward an outlet, wherein the silicone polymers or silicone compositions are fed by a feed at the top of the cylinder onto the inner wall, and
evaporating volatile constituents and collecting a high viscosity silicone polymer or silicone composition containing less volatiles, wherein the viscosities are measured at 25° C. in accordance with DIN 54458.

2. The method of claim 1 , wherein the volatiles comprise D3 to D30 cyclic polysiloxanes and linear polysiloxanes having 2 to 30 silicon atoms.

3. The method of claim 1 , wherein the silicone polymer is a silicone polymer containing no functional groups, a silicone base polymer having condensable end groups, a silicone base polymer having unsaturated alkyl groups, or Si—H, Si-vinyl, phenyl-containing or fluorine-containing silicone base polymers.

4. The method of claim 1 , wherein the silicone composition comprises an RTV-1, RTV-2, or LSR composition.

5. The method of claim 1 , wherein the high-viscosity silicone composition contains at least 40 wt % of organopolysiloxane.

6. The method of claim 1 , wherein the high-viscosity silicone composition comprises fillers.

7. The method of claim 1 , wherein the absolute pressure in the short path evaporator is 0.01 Pa to 500 Pa.

8. The method of claim 1 , wherein the temperature of the high-viscosity silicone polymer or high viscosity silicone composition in the short path evaporator is 150° C. to 240° C.

9. The method of claim 1 , wherein the high-viscosity silicone polymer or high viscosity silicone compositions are heated before being fed into the short path evaporator.

10. The method of claim 1 , wherein the silicone polymers or high viscosity silicone compositions are degassed before entry into the short path evaporator.

11. The method of claim 9 , wherein heating is effected by exposing the high viscosity silicone polymer or high viscosity silicone composition to high shear.

12. The method of claim 1 , wherein volatiles are removed from a high viscosity silicon composition containing a filler selected from the group consisting of silica, carbon black, silicon-aluminum oxides, and mixtures thereof.

Assignees

• Wacker Chemie Ag

Inventors

• Becker Nils
• Becher Dominik
• Fuerst Josef
• Schuster Johann

Classifications

• C08G77/34 Primary

  Purification · CPC title

• B01D5/0045

  Vacuum condensation · CPC title

• B01D1/225 Primary

  with blades or scrapers · CPC title

• B01D1/0082

  Regulation; Control · CPC title