Mould Release agents are an integral part of the composite moulding process and are vital to the successful production of high quality FRP components.
Semi-permanent Mold release
When applied to release agents, the term ‘semi-permanent’ usually refers to those products which function by depositing a micro-thin film on the surface of the mould.
Semi-permanent release agents allow multiple releases from moulds, making them ideal for high volume production processes such as resin transfer moulding (RTM).
There is no build-up or transfer of release agent, so the need for cleaning of moulds and/or mouldings is reduced to a minimum. It is vital when using these unique release systems that the mould surface is perfectly clean to ensure good film formation and proper cure of the release coating.
Internal Release Agents
Internal release agents are used mainly in high volume, mechanized processes such as pultrusion, RTM and SMC / DMC hot press moulding. A suitable product is dissolved in the resin mix and during processing it migrates to the surface and forms a barrier between the resin and the mould.
How Release agent works
|Semi-Permanent Releases||Conventional Mold Release WAX, PVA, Polymeric|
|Strong chemical bond||Weak surface adhesion|
|Release film cross-links on exposure to atmosphere or temperature bonding to mold||Evaporation deposits a release film on the mold surface|
|Reactive resin solutions||Release sits on the mold surface|
|Cross link and cures on the mold||Forms a physical barrier|
|Forms a chemical barrier||Fills pores in the mold surface|
|Thin, strong coatings||Subject to transfer/buildup|