High strength mould making rubber developed for prototype design and production tooling, outstanding release properties, translucent appearance allows split lines to be cut accurately in block moulds, very low shrinkage and good dimensional stability, high hardness, but flexible and very tough, Cures at room temperature by addition reaction.
|Polycraft K4 ||Unit |
|Mix Ratio By Weight ||1A : 1B |
|Pot Life @ 20°C ||90 mins |
|Demould Time @ 20°C ||8 - 9 hrs |
|Shore A Hardness ||A40 |
|Viscosity (mPas) @ 25°C ||40000 |
|Tensile Strength MPa ||>6.0 |
|Elongation At Break % ||380 (Approx) |
|Resistance To Tear N/mm ||>25.0 |
|Cure Colour ||Translucent |
K4 is a two component material. Cures at room temperature by addition reaction. A range of materials can be cast into the cured silicone mould, polyurethane and other reactive resins are the materials typically used.
Note : If no vacuum de-airing equipment is available, air entrapment can be minimised by mixing a small quantity of base and curing agent, then using a brush & painting the original with a 1-2mm layer before continuing with pour.
Inhibition of Cure
Great care must be taken when handling and mixing all addition-cured silicone elastomer systems, that all the mixing tools (vessels and spatulas) are clean and constructed in materials which do not interfere with the curing mechanism, do not use wood and paper mixing utensils. The cure of the rubber can be inhibited by the presence of compounds of nitrogen, sulphur, phosphorus and arsenic; organotin catalysts and PVC stabilisers, epoxy resin catalysts and even contact with materials containing certain of these substances e.g.. moulding clays, sulphur vulcanised rubbers, condensation cure silicone rubbers, wood, paper, cardboard, onion and garlic.
Base and catalyst use universal containers for various kit sizes and are supplied by weight, while the supplied containers may not be full, they will contain the correct amount of both base and hardener according to the listing. At point of packaging and dispatch lids may be taped to prevent damage or spillage during transportation.