Process for regenerating sulfur-crosslinked rubber vulcanizates to give regenerates

Patent metadata

Field	Value
Publication number	US-9683088-B2
Application number	US-201514635634-A
Country	US
Kind code	B2
Filing date	Mar 2, 2015
Priority date	Aug 31, 2012
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A process for regenerating sulfur-crosslinked rubber vulcanizates to regenerates, wherein at least one regenerating agent is used in the regeneration. The regenerating agent is selected from the group consisting of dithiophosphoryl polysulfides and/or silanes having a polysulfane group. Regenerates which have been produced by means of the process lead to improved or equal rolling resistance indicators and a lower compression set in vulcanized rubber mixtures compared to regenerates known in the prior art.

First claim

What is claimed is:

1. A process for regenerating sulfur-crosslinked rubber vulcanizates to give regenerates comprising:
providing at least one regenerating agent for regenerating sulfur-crosslinked rubber vulcanizates,
wherein the regenerating agent is selected from the group consisting of dithiophosphoryl polysulfides and silanes having a polysulfane group, and
mixing a mixture of the at least one regenerating agent and sulfur-crosslinked rubber vulcanizates for a period of time of from 5 to 35 minutes.

2. The process as claimed in claim 1 , wherein the dithiophosphoryl polysulfide has the general formula I

where R 1 and R 2 are identical or different and are selected from among linear or branched C 3 -C 20 -alkyl radicals and x=1 to 6.

3. The process as claimed in claim 2 , wherein the dithiophosphoryl polysulfide is a bis(O,O-2-ethylhexyl)thiophosphoryl polysulfide.

4. The process as claimed in claim 1 , wherein the silane having a polysulfane group has the general formula II
(R 2 O) 3-y R 3 y —Si—R 1 —S x —R 1 —Si—(OR 2 ) 3-z R 3 z   (II)

where x=1 to 8 and the radicals R 1 in a molecule are identical or different and are selected from among linear or branched C 1 -C 18 -alkyl radicals, the radicals R 2 and R 3 in a molecule are identical or different and are selected from among linear or branched or cyclic saturated C 1 -C 30 -alkyl radicals and y and z are identical or different and are each from 0 to 3, wherein the radicals R 2 and/or R 3 optionally contain from 1 to 10 nitrogen atoms (N) and/or oxygen atoms (O) as heteroatoms in the carbon chain.

5. The process as claimed in claim 4 , wherein the silane having a polysulfane group is a bis(trialkoxysilyl)propyl polysulfane.

6. The process as claimed in claim 4 , wherein the radicals R 2 and/or R 3 additionally contain from 1 to 10 nitrogen atoms (N) and/or oxygen atoms (0) as heteroatoms in the carbon chain.

7. The process as claimed in claim 1 , wherein the silane having a polysulfane group has the general formula V
(R 2 O) 3-y R 3y —Si—R 1 —S x —R 1 —Si—(O 2 R 2 )R 3   (V)

where x=1 to 8 and the radicals R 1 in a molecule are identical or different and are selected from among linear or branched C 1 -C 18 -alkyl radicals, the radicals R 2 in a molecule are identical or different and are selected from among linear or branched or cyclic saturated C 1 -C 30 -alkyl radicals and y and z are identical or different and are each from 0 to 3 and the radicals R 3 in a molecule are identical or different and are selected from among linear or branched C 1 -C 10 -alkyl or alkoxy radicals.

8. The process as claimed in claim 1 , wherein the silane having a polysulfane group has the general formula VI
(R 2 O 2 )R 3 —Si—R 1 —S x —R 1 —Si—(O 2 R 2 )R 3   (VI)

where x=1 to 8 and the radicals R 1 in a molecule are identical or different and are selected from among linear or branched C 1 -C 18 -alkyl radicals, the radicals R 2 in a molecule are identical or different and are selected from among linear or branched or cyclic saturated C 1 -C 30 -alkyl radicals and the radicals R 3 in a molecule are identical or different and are selected from among linear or branched C 1 -C 10 -alkyl or alkoxy radicals.

9. A process for regenerating sulfur-crosslinked rubber vulcanizates to give regenerates, comprising:
placing the sulfur-crosslinked rubber vulcanizate to be regenerated in amounts of from 68 to 98% by weight in a mechanical mixer;
heating the sulfur-crosslinked rubber vulcanizate to be regenerated to a temperature of from 50 to 70° C.;
adding at least one dithiophosphoryl polysulfide and/or at least one silane having a polysulfane group in amounts of from 2 to 15% by weight to form a mixture; and,
mixing the mixture for a period of time of from 5 to 35 minutes at a temperature of from 80 to 150° C.

10. The process as claimed in claim 1 , wherein the sulfur-crosslinked rubber vulcanizates originate from used tires or conveyor belts or vulcanized waste obtained in the production of industrial rubber articles or pneumatic vehicle tires.

11. A regenerate produced as claimed in the process as claimed in claim 1 .

12. The regenerate as claimed in claim 11 for producing pneumatic vehicle tires.

13. A process of regenerating sulfur-crosslinked rubber vulcanizates comprising adding dithiophosphoryl polysulfides as regenerating agents, and
mixing the resulting mixture for a period of time of from 5 to 35 minutes.

14. A process for regenerating sulfur-crosslinked rubber vulcanizates comprising adding silanes having a polysulfane group as regenerating agents, and
mixing the resulting mixture for a period of time of from 5 to 35 minutes.

Assignees

• Continental Reifen Deutschland Gmbh

Inventors

• Recker Carla
• Mueller Lena
• Voelker Thomas

Classifications

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• B29B7/7495

  for mixing rubber · CPC title

• Y02W30/702

  Cross-Sectional Technologies · mapped topic

• C08J11/10 Primary

  by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation (depolymerisation to the original monomer C07) · CPC title

• C08K5/5398

  Phosphorus bound to sulfur · CPC title