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TAC Taicros

Epichlorohydrine rubber

Applications

TAC/TAICROS®

Environmentally friendly crosslinking of epichlorohydrine rubber (ECO) Substitution of lead/ETU crosslinking system


For health and environmental reasons the use of epichlorohydrine rubber (ECO) formulations with a lead/ETU containing crosslinker system is prohibited in automotive applications and also restricted in many other applications.
Our TAICROS® TMT is an environmentally friendly alternative crosslinker for ECO, which in combination with an acid scanvanger like MgO/CaCO3 can replace the lead/ETU crosslinking system.
Advantages
  • Excellent crosslinking properties
  • Nontoxic/no hazard classification
  • No migration, bound to the rubber matrix
Application
The main application for this system is fuel hoses.
Toxicity comparison
The following table shows a comparison of the toxicity data of TAICROS® TMT versus ETU. In vitro toxicity, carcenogenicity as well as teratogenicity of TAICROS® TMT were not tested, since the available data give no indication for concern.
 
TOX data and safety information
Property
TAICROS® TMT
ETU
Hazard classification
None
Toxic (T)
LD50 rat oral
9,500 mg/kg
710 mg/kg
Skin irritation
Not irritating
Slight irritation
Eye irritation
Not irritating 
Slight irritation
Gene toxicity in vitro
Not tested
Mutagenic
Carcinogenity
Not tested 
Carcinogenic
Teratogenity
Not tested
Teratogenic
Crosslinking mechanism
In the lead/ETU system lead functions as crosslinker as well as acid acceptor, by abstracting the polymer bound chlorine and supporting the formation of -CH2–O–CH2-bridges. Whereas ETU (ethylene thio urea) only functions as an accelerator and is not bound to the crosslinked polymer system.
In contrast to this TAICROS® TMT is the crosslinking reagent, which is incorporated into the polymer system according to the following postulated reaction mechanism, with the advantage that it cannot migrate from the final rubber part:
MgO and CaCO3 on the other side work as acid scavangers.