Any experience with inert gas purge or evacuated molds for rubber
Any experience with inert gas purge or evacuated molds for rubber
(OP)
Has anyone had any experience with the subject matter, and could you point me towards a reference that talks about this matter? We are having trouble with air inhibition of cure in molding and bonding (to primered bronze substrate) of a peroxide-cured EPDM. I have seen one referenced paper (abstract only) in a google search, apparently in German, that talks about using inert gas purging and mold cavity evacuation (vacuum pumping) in rubber injection molding. Wondering if this technique is useful or not before spending time and resources tracking down that lone paper, and then paying to have it translated.





RE: Any experience with inert gas purge or evacuated molds for rubber
RE: Any experience with inert gas purge or evacuated molds for rubber
Thanks anyway, tdd10.
RE: Any experience with inert gas purge or evacuated molds for rubber
All the presses at my previous employer used vacuum chambers surrounding the molds and the vacuum would be on full tilt during the molding process (compression, injection, and transfer), this prevented trapped air/gases in most molds.
Unbonded patches usually indicated that the rubber wiped away the bonding agent or indicated poor coverage in the first place. If wiped away, a mold design change would be needed.
Difficult to bond combinations of metal and rubber utilized a special bonding agent and/or a roughed up insert surface similar to sand blasting but in your case probably with a less aggressive media, thus creating a physical bond along with the chemical one.
If you are still having problems try roughening the inserts, then different different bonding agent.