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External release agents have a limited life and when re-applying the release agent the mould is out of production. PAT internal mould release (IMR) is added directly to the gel coat and resin to greatly extend the number of de-mouldings between external release agent applications. This keeps the mould in production for longer, and the surface quality of the moulding is improved and more consistent.

– No effect on cure
– No effect on pigment
– Totally soluble and stable in the resin, no separation
– No negative influence on laminates properties
– Good surface finish, excellent release
– No pre release
– Easy and safe to use, store and transport
– Inhibits resin build up on mould
– No effect on painting or bonding


PAT-657/C 0.6 to 1% Polyester & DCPD
PAT-656/B3R 1.2% Epoxy
PAT-672 0.5 to 1% Polyester gel coat

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Add 0.5% by weight of PAT-672 to gel coat and mix well, it is better to add to a large quantity of gel/resin to get the best accuracy when adding small percentages. By having an IMR the external release applied will last longer and the surface will be improved.

The addition level can be adjusted; it can be increased up to the point where the surface feels greasy. Normal addition range is 0.5% to 1% based on gel/resin weight.

In the RTM process surfaces which are not gel coated suffer from abrasion of the release agent when the mould is closed caused by the glass fibre. This leads to rapid build up of polymerised styrene, partially cured resin and other contaminants.

Cleaning the build up usually involves solvents and aggressive scrubbing which will damage the surface.

By using 0.6% of PAT-657/C in the resin (PAT-656/B3R at 1.2% for epoxy resin), the build up is greatly reduced and cleaning is necessary much less frequently.

Addition level can be increased up to 1% as necessary, a greasy surface means too much is being added and should be reduced slightly.

Essentially PAT internal mould release agents are soluble in the liquid resin, as polymerisation and cross linking occurs during the cure process, our product drops out of solution and its forced to the surface.

PAT release agents do not affect resin/gel coat bond. All products have been rigorously tested to meet your performance expectations and are manufactured to ISO9001 standard and also ISO 14001 environmental control standard.

For further information or assistance regards our products or the RTM process please contact us, we are always happy to help.