The abrasive property of kaolin is what gives rubber its strength and stiffness
Kaolin is an ideal additive to rubber due to its anisometric ‘booklet’ particle structure which adds strength and stiffness to the product through enhanced stress transfer. Kaolin clay is a low cost substitute for precipitated silica and carbon-black in certain compounds without sacrificing physical properties.
Kaolin clay is used to improve the tensile and modulus of ground calcium carbonate based rubber compounds. ‘Soft’ kaolin clays have larger grain sizes and are used where high loadings (for economy) and faster extrusion rates are more important than strength. ‘Hard’ kaolin clays with smaller particle sizes impart high modulus, high tensile strength, stiffness, and good abrasion resistance to rubber compounds. 80% of the clays used in rubber production are Air Float hard clays, which are air separated to remove impurities. Surface treated hard clays provide even better reinforcement than untreated clays and has the capability to substitute carbon-black in certain applications.
Special functionalities such as improved air-permeability can be imparted in hydrous kaolin clays through the process of delamination. Calcined kaolin or water washed clay, is used in certain applications such as wire and cable manufacturing as it provides good reinforcement, better colour and higher volume resistivity.
The hydrous Kaolin is used as reinforcing filler in rubber formulation, the inclusion of kaolin will improves the ease of extrusion, the tear strength, tensile strength, resistance to abrasion, the durability and rigidity of rubber. Regular grade Kaolin is used in footwear, conveyor belts, and rubber sealants and molds while high end kaolin is used in tire compounds. Processed clay such as KCG SD is most suitable in this application and is a benchmark with leading Indian footwear producers formulating with it.
KCG P- As a filler in special quality rubber components, plastics and cables
KCG SD – Reinforcing filler in rubber products
KCG SDR – Reinforcing filler in rubber products
Himacem – Ad mixture in Concrete; High Reactivity Metakaolin is now established as a value- added Concrete Ad-mixture.
Himarub – Molding and extrusion of automotive and non-automotive rubber components/products such as seals, hoses, conveyor belts, window profiles, pharmaceutical bottle stoppers and discs.