Solvent-based semi-permanent mold releases are often very sensitive to moisture. Leaving these products open or repeatedly exposing them to the atmosphere can cause polymerization in the can. This degradation may be invisible, but can compromise the performance.

One way to reduce risks when using moisture-sensitive mold releases is to dispense the release into heavy duty HDPE bottles with flip-top caps. Siphon-type bottles are not suitable, as they draw in air each time they are squeezed. Low density or other plastics should be avoided. Open cans, (paint) trays, buckets, etc. of release should definitely be avoided. Large containers of release can be conserved with a desiccant drum drier or by purging with nitrogen after dispensing.

Remember that these are general guidelines. Each molder should assess the materials they are working with and decide which combination of mold strippers, cleaners, sealers and release agents are most appropriate in their situation. Contact your supplier if you have any questions about your mold release programs. Your supplier should work with you to establish the right care and handling procedures.

Scott Waterman is director of global sales at AXEL Plastics. Email comments to

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