polyurethane tackiness

[Beorges]

Team I had a molded very thin wall polyurethane rubber

After the molding the parts are so sticky that I put them into a chlorine bath

The problem is that after the wash the parts suffer from discoloration

There is any alternative lubricant/coating to decrease this tackiness and stiffness ?

Taking into account that this is a medical application.

Regards

 

[GrahamBennett]

Diluted silicone oil spray (like mould release)?

 

[GregLocock]

talc.

some oils might work. Might be worth talking to a chemist.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[btrueblood]

It sounds as if the urethane was not fully mixed, not mixed in the right ratio, or not subjected to a long enough cure at a high enough temperature...i.e. you have un-cured parts.

Did you perhaps not put in a full amount of "hardener" expecting to get a finished product with a lower durometer (lower stiffness)? That don't work. Get a compound that is formulated to cure at a lower durometer, and mix at the recommended ratios.