When rubber, PU foam or potting compound sticks in the mould, the first fix is a fresh release film on a clean tool. Micron 1100 Silicon Mould Release Agent lists rubber component moulding, polyurethane and foam moulding, and electronics potting and encapsulation among its applications. For tyre moulds there is a purpose-made treatment (1150), and if the rubber part will be bonded or painted later, consider the non-silicone 1110 after a trial.
Why it happens
Rubber and foam are tacky during cure and grip any surface that is not protected. Common causes:
- No release film, or a worn-out one. The film wears off over repeated cycles and the compound starts to bond to the steel.
- Compound build-up on the mould. Residue from earlier cycles roughens the surface and gives new material something to hold onto.
- Mould temperature too high or too low for the compound. Cure that is too fast or too slow changes how the part releases.
On the floor you will see rubber tearing or leaving residue on demoulding, PU foam skin sticking to the tool, or potting and encapsulation moulds that are hard to release.
How to fix it
Pick by part type:
- General rubber moulding, PU foam, or electronics potting and encapsulation: Micron 1100 Silicon Mould Release Agent. Its page lists rubber component moulding, polyurethane and foam moulding, and electronics potting and encapsulation, and says one spray delivers multiple releases.
- Tyre moulds: Micron 1150 Tyre Mould Treatment Spray, a silicone treatment specially formulated for tyre moulds and rubber moulding.
- Rubber part will be bonded or painted after moulding: Micron 1110 Non Silicon Mould Release Agent lists rubber moulding and is non-silicone. Bonding or paint compatibility is not stated, so trial a part through your bonding or paint step first.
- Old release agent, grease or wax has built up on the mould: clean it with Micron 1220 Mould Cleaner, which its page says removes grease, silicones, waxes and mould-release agents. Then re-apply release.
The 1100 page has no step-by-step directions. Follow the instructions on the can and the TDS: a light, even coat on a clean mould, reapplied when parts start to grip.
What to avoid
- Avoid silicone release where the rubber part must later be bonded or painted. Silicone on the surface can stop adhesives and paint from sticking.
- Do not over-apply. Excess release can transfer to parts.
- 1220 Mould Cleaner is a solvent cleaner. Treat it as flammable until the SDS says otherwise: keep it away from sparks, flames and hot surfaces, and use it with ventilation. Let the mould cool before cleaning.
- Do not use release agent to hide compound or temperature problems.
When to ask an expert
Consult your compounder or process engineer if:
- sticking started with a new rubber grade or compound;
- the tool surface is damaged, pitted or worn;
- parts still stick with a fresh film on a clean mould.
Compound-specific sticking and tool damage are not problems a release agent can solve.
FAQ
Can I use the same release agent for rubber and plastic?
Micron 1100 lists both: PVC, ABS, polypropylene and nylon, plus rubber, PU foam and die-cast components. Whether it suits your compound is something to trial on a short run.
My rubber gasket tears on demoulding. Is it the release?
It can be a worn release film, but tearing also comes from undercuts, sharp corners in the cavity, or demoulding before the part has cured. Check the release first on a clean mould, then look at the tool and the cure.
Do I need a special release for PU foam?
The 1100 page lists polyurethane and foam moulding. Start there and test on your foam system.
Should I clean the mould before switching release agents?
Yes. Old release and grease on the tool can mix with the new film. 1220 Mould Cleaner is stated to remove silicones, waxes and mould-release agents.
See the product: Micron 1100 Silicon Mould Release Agent. Related: 1150 Tyre Mould Treatment Spray, 1110 Non Silicon Mould Release Agent, 1220 Mould Cleaner. More moulding fixes: moulding hub.