WHY RELEASE AGENTS?
Whether release agents are incorporated into the resin matrix or applied externally to the mould surface, correct selection can optimise not only cycle time, but also consistency of surface finish maintaining detail, minimising post mould operation prior to painting or bonding, even helping with fibre wet out. To work well a release agent must fit within the scope of the overall process and be cost effective. Application must be simple with clearly defined steps, drying times should be short and cure time if any must not delay the process. The product must not contain any ingredients which will affect the final product properties or post mould treatments. Finally release must be smooth and clean with no pre-release prior to cure. Qualification costs are high and CRC ensure their products and chemical pre-cursors are available long term, anticipating changes in legislation and using safe ingredients whenever possible.
Internal Mould Release Agent (IMR)
A product dissolved in the resin mix, which is highly soluble in the carrier solvent i.e. styrene. During cure the product drops out of solution and migrates to the surface due to volumetric shrinkage, pressure and temperature.
The following criteria are desirable:
- Total solubility in the system
- Minimal effect on cure
- Minimal effect on colour
- No negative and preferably positive influence on physical properties
- No silicone, non-stearate and no natural waxes which would adversely affect painting or bonding adhesives
- A consistent clean release with no build-up or mould fouling caused by deposits
- Measurable reduction in cycle time Using an internal requires careful introduction.
Each release agent application is not an individual event, it is part of a long running sequence. Each moulding relies as much on previous moulding as it does on the IMR it deposits during its own cycle. (This is a continuous process in pultrusion).
IMR’s are more commonly associated with mechanised processes, but can assist in difficult highly detailed hand lay-up mouldings.
One major advantage is consistency and in high volume production, externally applied release systems rely solely on operator skill, not always meeting the requirements of the designer or formulating chemist. CRC are the market leader in this area and have many successful applications mainly in the RTM, cold press and spray up.
External Mould Release Agent
Externals are applied to the mould surface and as such rely on care and attention during application to ensure successful release.
The following criteria are desirable:
- Easy application with no complex instructions
- No harmful solvents
- Good wetting of all surfaces i.e. should not shrink back when applied
- Surface tension should be correct for gel coat application
- Quick drying
- Easy to polish
- Transfer to moulding should be easily removed, (preferably with water)
- Predictable multiple release
Wax release agents are used typically in low volume manufacturing where products are individual and cycle times are not critical, semi-permanents are used in high volume applications.
The Marbocote system is ideal for all contact mouldings, large or small, giving exceptional surface finish with low maintenance, but without critical application procedures.
In high production processes such as RTM, the use of Marbocote semi-permanent systems maximises cycle times because of their consistent release properties.
High Pressure Laminate & Melamine Faced Chipboard
All aspects covered. [Click to request more information]
- Release agents, wetting agents, anti-block additives, anti-dust additives, antifoams and cleaners
- Combined release and wetting agents very efficient with low foam generation
- Back face release for HPL in continuous belt and multidaylight presses
- Long running maintenance free
- Wetting agents and flow promoters which do not influence colour or surface porosity
- Anti-block and anti-tack additives for prevention of blocking in high humidity and temperature conditions
- Standard additive for many European companies as well as those in warmer climates, a useful insurance
- Anti-foam additives available separately or supplied pre-mixed with other grades
- Anti-dust additives for problem papers
- Cleaning papers now available
- Special products to keep press surfaces clean when changing size of pressed area
- All wetting agents now non NPE
- New ultra safe environmental grades
- Full technical service and back up, we are market leaders in supply and innovation.