Air entrapments in closed cell foam rubber
Air entrapments in closed cell foam rubber
(OP)
Hello everyone,
We manufacture closed cell foam products at our facility by compression molding. Currently we are experiencing severe air entrapment issues with our SBR/EPDM/Neoprene blend stocks. Could anyone give any ideas why this could be happening all of sudden? Where do entrapments normally occur, extrusion, molding, mixing? When the air traps are cut open there is a cured skin inside, no contamination. Any ideas or solutions will be greatly appreciated! Thanks
We manufacture closed cell foam products at our facility by compression molding. Currently we are experiencing severe air entrapment issues with our SBR/EPDM/Neoprene blend stocks. Could anyone give any ideas why this could be happening all of sudden? Where do entrapments normally occur, extrusion, molding, mixing? When the air traps are cut open there is a cured skin inside, no contamination. Any ideas or solutions will be greatly appreciated! Thanks





RE: Air entrapments in closed cell foam rubber
unfortunately you do not mention size of "hole" in relation to foam cell size. If it is not too big I would suspect some coarse pieces or undispersed aggregates of the blowing agentin the compound. Bigger holes should have "mechanical" reason.
HTH
Berti
RE: Air entrapments in closed cell foam rubber
RE: Air entrapments in closed cell foam rubber
RE: Air entrapments in closed cell foam rubber
Finally, have you noticed any problems during the summer months when the humidity levels are much higher than in winter? If this is the case, make sure your temperatures are all above due point (I would recommend using 50°C in any case for the mixer, higher on the mills and extrduer) to ensure no condensation occurs.