Rubber Accelerators 2

[Lejca]

Dear all,

I have a problem with unpleasant odor of accelerator using with SBR.
We’ve been using MBTS and TMTD and we were very satisfied. Unfortunately we're not allowed to use MBTS anymore and we have to find alternative.
But all combination of accelerators I've tried has unpleasant odor.
- ZBEC + ZADP
- ZBEC + PO
- ZBEC + TMTD
- ZBEC + TBzTD
- PO + TMTD
- ZADP + TMTD

CBS and DPG - I can't use them bacause they can't be used for white and light colors

Does any of you have any suggestion what kind of accelerator should I try?

Thank you,

Lea

 

[stancom]

Afraid I've been out of compounding too long to be familiar with more recent accelerators, but don't forget there are two other approaches to this type of problem. Ineffective though this may sound, heating or steaming the product or subjecting it to a blast of air can sometimes help, repeated if necessary. Naturally we would be thinking of fairly thin sections. The other rather more obvious method is to add a deodorant or reodorant to the mix provided an approved one can be found.

 

[GrahamBennett]

Why are you not allowed to use MBTS any more? It is does not produce nitrosamines as far as I'm aware. If this is the case, then what about using TBBS or DCBS in conjunction with TBzTD? In my opinion the problem probably lies with TMTD rather than MBTS but I'm willing to stand corrected on this.

 

[Lejca]

Thank you for your answers.
For now I solved the problem with Zeolite but I will try suggested combinations of accelerators too.
The real problem is with MBT which was found in our products (MBTS decomposes on MBT) and is not allowed. That's why I decided to change the accelerator as I don't know the mechanism of the reaction and I want to make sure that there won't be MBT anymore in our products.

 

[GrahamBennett]

OK, thanks for the explanation. All sulfenamides breakdown at faster or slower rates to give MBT, which is the active accelerator. Under German legislation CBS, TBBS and DCBS are deemed to be SAFE as far as nitrosamine generation is concerned. If you can get hold of a copy, The Encyclopedia of Polymer Science and Technology by Herman F. Mark has a full explanation on pp1065 onwards.

 

[tom1953]

Can you advise what product you're making? and what regulation doesn't allow the presence of MBT?
Thanks,
tom

 

[Lejca]

Thank you for advising me The Encyclopedia of Polyimer Science and Technology, I've read this non-nitrosamine part.
We're in footwear industry and the problem with MBT is in its skin sensitisation

http://ec.europa.eu/health/archive/ph_risk/committees/04_sccp/docs/sccp_o_00i.pdf

 

[tom1953]

Lejca, thanks for the link. It's a study of MBT (and two AOs) primarily in soothers and teats (pacifiers and baby nipples). Interestingly, the first conclusion of the study is:
The risk of sensitisation from exposure to MBT released from natural rubber soothers and teats is negligible.
tom

 

[Lejca]

Yes Tom, I know. But customer requirements are our priority.