Method for producing rubber-modified bitumen using vulcanized rubber

Patent metadata

Field	Value
Publication number	US-10844190-B2
Application number	US-201615752375-A
Country	US
Kind code	B2
Filing date	Aug 17, 2016
Priority date	Aug 21, 2015
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

The present invention provides a novel process for producing rubber-modified bitumen using vulcanized rubber.

First claim

What is claimed is:

1. A process for producing rubber-modified bitumen using vulcanized rubber, the process comprising:
devulcanizing the vulcanized rubber by breaking the sulfide bridges thereof by contacting the vulcanized rubber with at least one dialkyl polysulfide of the general formula (1)
R 1 —S x —R 2   (1)

where R 1 and R 2 are the same or different and are a linear or branched C 1 -C 18 -alkyl radical and x represents the numbers from 3 to 12, at temperatures in a range of from 140° C. to 170° C. for a time of from 20 to 60 minutes, where the proportion of the dialkyl polysulfide is from 1.5% to 4% by weight, based on vulcanized rubber, and
mixing the devulcanized rubber into the bitumen.

2. The process as claimed in claim 1 , wherein the contacting further comprises contacting the vulcanized rubber with the dialkyl polysulfide with an oil.

3. The process as claimed in claim 1 , wherein the contacting of the vulcanized rubber to break the sulfide bridges and/or the mixing into the bitumen are effected under mechanical stress.

4. The process as claimed in claim 1 , wherein the dialkyl polysulfide is branched dioctyl pentasulfide or branched dioctyl tetrasulfide.

5. The process as claimed in claim 1 , wherein x represents the numbers from 3 to 8.

6. The process as claimed in claim 1 , wherein R 1 and R 2 are linear or branched C 5 - to C 15 -alkyl radicals.

7. The process as claimed in claim 1 , wherein x represents the numbers from 3 to 8, and R 1 and R 2 are linear or branched C 5 - to C 15 -alkyl radicals.

8. The process as claimed in claim 1 , wherein the dialkyl polysulfides are dialkyl tetrasulfides.

9. The process as claimed in claim 1 , wherein the contacting further comprises contacting the vulcanized rubber with the dialkyl polysulfide and up to 30 wt % mineral oil based on the rubber mixture to be devulcanized.

10. The process as claimed in claim 8 , wherein the proportion of the dialkyl polysulfide is 1.5% to 3% by weight, based on the vulcanized rubber, the temperatures in the process is 150-160° C., the contacting is for a period of time 35-45 min; and the contacting further comprises contacting the vulcanized rubber with the dialkyl polysulfide and 1 to 6 wt % mineral oil based on the rubber mixture to be devulcanized.

11. The process as claimed in claim 1 , wherein the devulcanization time is 30-50 min.

12. The process as claimed in claim 1 , wherein the devulcanization time is 35-45 min.

13. The process as claimed in claim 2 , wherein the oil is mineral oil.

14. The process as claimed in claim 1 , wherein the dialkyl polysulfides are dioctyl tetrasulfides.

Assignees

• Lanxess Deutschland Gmbh

Inventors

• Klein Thomas
• Ziser Torsten

Classifications

• C08L19/003 Primary

  Precrosslinked rubber; Scrap rubber; Used vulcanised rubber · CPC title

• C08K5/372

  Sulfides {, e.g. R-(S)x-R'} · CPC title

• C08L2555/80

  Macromolecular constituents · CPC title

• C08L2555/22

  Asphalt produced above 140°C, e.g. hot melt asphalt · CPC title

• C08L95/00

  Compositions of bituminous materials, e.g. asphalt, tar, pitch · CPC title