Coal Industry (patents) Limited

Geoffrey Vincent Blunt

Newton John Hodges

Robert James Pragnell

A cellular material may be made by vulcanizing a mixture containing between 15% and 50% of an ebonite-forming rubber and sufficient vulcanizing agents to form an ebonite with the rubber, between 5% and 87% of a coal digested in pitch, tar or tar oil, between 10% and 40% of a particulate filler and a chemical blowing agent, whereby an ebonite structure is formed, so that, during the vulcanization, the chemical blowing agent decomposes or reacts to produce a gas, the viscosity of the composition during the production of the gas increasing whereby cells are retained in the composition. The digested coal has a penetration, converted to a Ring and Ball softening point of 85.degree. C, of between 10 and about 45. Cellular plastics material produced by this process may contain at least 25% by volume of closed cells.

Cellular material

The invention comprises the production of a cellular material by vulcanizing a mixture containing between 10% and 90% of an ebonite-forming rubber and sufficient vulcanizing agents to form an ebonite with the rubber, not more than 10% of a solid filler preferably in the absence of such filler, and a chemical blowing agent, whereby an ebonite structure is formed, so that, during the vulcanization, the chemical blowing agent decomposes or reacts to produce a gas, the viscosity of the composition during the production of the gas increasing whereby cells are retained in the composition wherein the mixture further contains between 5% and 87% of a bituminous material.

Cellular materials based on epoxy resins are known but are difficult to manufacture because of high exotherm. The addition of coal pitch which may be coal tar pitch or coal digest mitigates this to an extent not related to the heat capacity of the coal pitch. Cellular materials having fine even cells can easily be made. Certain epoxy resins enable flexible cellular materials to be manufactured.

Growing community of inventors

Cheltenham, United Kingdom

Geoffrey Vincent Blunt