Process for devulcanizing rubber

Patent metadata

Field	Value
Publication number	US-10077350-B2
Application number	US-201615392031-A
Country	US
Kind code	B2
Filing date	Dec 28, 2016
Priority date	Sep 28, 2012
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A process for devulcanizing EPDM rubber comprising the step of introducing sulfur-cured EPDM to an extruder, introducing from about 0.5 to about 20 wt % scavenging agent, based upon the total weight of the EPDM and scavenging agent, and mixing and masticating the EPDM at a temperature sufficient to at least partially devulcanize the sulfur-cured EPDM.

First claim

What is claimed is:

1. A process for devulcanizing EPDM rubber comprising the steps of:
introducing sulfur-cured EPDM to an extruder;
introducing an oxide or a carbonate of an alkali metal or alkaline earth metal to the extruder, wherein the oxide or a carbonate of an alkali metal or alkaline earth metal is introduced so as to protect against degradation of the extruder; and
mixing and masticating the EPDM within the extruder in the presence of the oxide or a carbonate of an alkali metal or alkaline earth metal at a temperature sufficient to at least partially devulcanize the sulfur-cured EPDM.

2. The process of claim 1 , further comprising the step of removing volatiles from the extruder.

3. The process of claim 2 , where the volatiles are removed from a vent.

4. The process of claim 1 , where said step of introducing includes introducing from about 0.5 to about 20 wt % of the oxide or a carbonate of an alkali metal or alkaline earth metal based upon the total weight of the EPDM and the oxide or a carbonate of an alkali metal or alkaline earth metal.

5. The process of claim 1 , where said step of introducing includes introducing from about 1.0 to about 10 wt % of the oxide or a carbonate of an alkali metal or alkaline earth metal based upon the total weight of the EPDM and the oxide or a carbonate of an alkali metal or alkaline earth metal.

6. The process of claim 1 , where said step of introducing includes introducing from about 1.5 to about 5 wt % of the oxide or a carbonate of an alkali metal or alkaline earth metal based upon the total weight of the EPDM and the oxide or a carbonate of an alkali metal or alkaline earth metal.

Assignees

• Firestone Building Prod Co Llc

Inventors

• Wang Hao
• Hubbard Michael J

Classifications

• B29L2007/005

  Tarpaulins · CPC title

• 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

• C08J11/12

  by dry-heat treatment only · CPC title

• B29K2023/16

  EPM, i.e. ethylene-propylene copolymers; EPDM, i.e. ethylene-propylene-diene copolymers; EPT, i.e. ethylene-propylene terpolymers · CPC title

• B29L2031/108

  Roofs · CPC title