CHT KÖRAFORM A 60 – Beige Addition-Cure Silicone for Mould Making & Rubber Parts

Premium Beige Addition-Cure Silicone for Professional Mould Making and Rubber Parts Applications

KÖRAFORM A 60 is a pourable, addition-cure two-component silicone system from CHT that cures at room temperature to a beige rubber with a hardness of Shore A60. With a pot life of 30 minutes at 23 °C and a mix ratio of 10:1 (A:B) by weight, the material allows time for mixing, degassing and pouring. Demouldable after approx. 12 hours, fully cured after approx. 24 hours (at 23 °C). Heat can accelerate curing. KÖRAFORM A 60 is suitable for reproducing master models and producing rubber parts where low dimensional change during curing is important.

Key Benefits

• Shore A60 hardness: – For relatively firm silicone rubber parts and mould applications.
• Linear shrinkage <0.1%: – Limits dimensional change during curing.
• Pot life 30 minutes at 23 °C: – Provides a defined working window for mixing, degassing and pouring.
• Tensile strength 4.5 N/mm²: – Documented mechanical property for assessing rubber parts.
• Elongation at break 140%: – Describes the extensibility of the cured rubber.
• Tear strength 5 N/mm: – Allows the tear resistance to be compared with other mould rubbers.

Typical Applications

• Reproduction of stereolithography master models for mould and model making, after a compatibility test.
• Mould and model making with pourable silicone rubber.
• Production of silicone rubber damping elements.
• Manufacture of technical rubber parts.
• Production of silicone rubber printing rollers.

Processing Instructions:

1. Stir component A and component B thoroughly, each separately, so that any settled fillers are evenly redistributed.
2. Weigh the components in a ratio of 10:1 (A:B), for example 100 g A and 10 g B. For optimum performance, use components A and B with the same lot number. Choose a clean plastic or metal mixing cup with approximately three times the volume of the mixture.
3. Mix until the mixture has a uniform colour. Mixing at 15–25 °C is recommended to retain sufficient pot life. Keep tools and equipment free of contaminants that can interfere with curing.
4. Preferably degas with interrupted vacuum at 30–50 mbar for 5–10 minutes; prevent overflowing. With automatic dispensing through a static mixing head, both components must be degassed before processing.
5. Pour by gravity or process by pressure injection within the pot life of 30 minutes at 23 °C.
6. Allow to cure at room temperature. Demouldable after approx. 12 hours, fully cured after approx. 24 hours (at 23 °C). Check before demoulding that the workpiece has cured sufficiently. Heating can accelerate curing. For an accelerated heat-cure schedule, please contact us.

Storage and Shelf Life

The technical data sheet states a storage temperature of 5–30 °C and a shelf life of 12 months. Store dry and protect from moisture and water. Store component A in tightly closed packaging. Component B must not be hermetically sealed and must be stored in suitable packaging with a degassing valve, as hydrogen gas may form. Keep component B away from water, alcohols, acids, bases, oxidising agents, heat and sources of ignition. Storage temperatures are not service temperatures of the cured rubber.

Manufactured by CHT Germany GmbH, supplier of silicone systems for mould and model making.

Important Warning: Inhibition with Addition-Cure Silicones

Please note: This is an addition-cure silicone with a platinum catalyst in component A. Nitrogen, sulphur, phosphorus and arsenic compounds, organotin catalysts, certain PVC stabilisers and epoxy resin catalysts can inhibit curing. Contact with certain modelling clays, sulphur-vulcanised rubbers and condensation-cure silicones can also cause problems. Use clean, suitable tools and, if in doubt, carry out a small compatibility test, particularly with stereolithography master models. With automatic dispensing, prevent component A from coming into contact with residual hydride-containing rubber in the equipment.

Professional Support

Need help processing KÖRAFORM A 60, assessing a master model or choosing a suitable mould rubber? Contact us for technical data sheets, processing guides or product advice.