Post-mix dwell time

[Elastomatt]

What is the preferred dwell time from mixing to processing? As a rule my current company leave material for 72hours before processing (NR, EPDM and NBR polymers). Is this excessive? I have previously worked in a company that kept to 48hrs.

What is the general opinion; pros and cons etc.

Thanks

 

[tom1953]

I always thought 24 hours/overnight was the norm.

 

[GrahamBennett]

Generally, I agree with Tom but work I carried out some years ago with NR/BR truck/bus tyre tread formulations showed that you can get away with about 3 hours and still get good extrusion performance.

 

[Elastomatt]

Thanks guys, when I worked in a compound development lab (many moons ago) we waited 24hours from mixing to moulding/extrusion (all moulding was compression). In production they used material after 48hours, once the material has completely cooled I couldn't think of a good reason for waiting longer....

Today we are injecting, compressing and extruding the compounds. I want to challenge this 72hour, but wanted to know what the general consensus was.

Thanks again...