Release Layers for Dry Demolding – Clean and Economical
From release agent reduction to release agent freedom
Producing molded plastic components of reactive polymers or thermoplastics release agents guarantee easy demolding and lead finally to an efficient production process. The use of release agents is however problematic: Conventional release agent systems often contain organic solvents that are hazardous to health and the environment. After demolding, residues of the release agents remain on the mold and component and these must be removed in subsequent cleaning steps. This has negative consequences for the productivity and a further environmental impact due to the cleaning solvents.
The Fraunhofer IFAM has therefore developed coating systems which completely avoid or drastically reduce the use of classical release agents:
- Coating of molds using low pressure (LP) plasma technology – for example, ReleasePLAS coating
- Coating of molds using atmospheric pressure (AP) plasma technology – for example, the Plasma Plus coating – a joint development with Plasmatreat GmbH
- FlexPLAS® deep-drawable release film from Fraunhofer IFAM – which is particularly suitable for the manufacture of large structures.
- ReleasePLAS® coating technology from the Fraunhofer IFAM which is particularly suitable for the manufacture of fiber reinforced plastics.
Properties of plasma-polymer release layers
Plasma-polymer release layers are dry layer systems with high cohesive strength so designed that they adhere effectively to the base surface yet allow the release process. By avoiding a “liquid” release agent, the coated mold and the component are all in direct solid-solid contact. The process must thereofore be designed in such a way that a peeling demold should possibly be realised, so that the interface will be least weighed down and the demold forces can decrease.
Plasma-polymer release layers are thin, typically of thickness between 0,1 and 2 µm. The coating process is surface-replicating, namely it is ideal for coating surface structures (graining, kinegram etc.). In those fields release agent free manufacture opens new applications and products.
In recent years many processes developed at Fraunhofer IFAM have been transferred to industrial practice. Indeed, this has generated much R&D work aimed at making plasma-polymer functional release layers even better and more effective.
- Polyurethane/PUR processing – in-mold coating (IMC), injection molding, hard foam, etc.
- Polyvinyl chloride/PVC slush process
- Processing carbon fiber reinforced plastics (CFRPs) and glass fiber reinforced plastics (GFRPs) – resin transfer molding (RTM), prepreg technology
- Organo sheet forming
- Moulding of thermoplast
- Thermoplastic polyurethane (TPU) injection molding
- Powder molding/PE rotomolding
- Elastomer processing – NBR (nitrile-butadiene-rubber), fluorine rubber, etc.
- Process of cold and hot melt
- Shorter cycle times
- Less or no contamination of the mold structure
- Longer mold service life
- Reduced emission of VOCs (volatile organic compounds) from release agents and mold cleaning agents
- Easier and faster mold cleaning, if necessary
- No contamination of the production area
- Uniform and improved surface quality
- No release agent transfer
- No complicated component cleaning
- Reliable further processing