About Harboro Rubber Engineering in Rubber      Contents      Introduction      Uses of Rubber      Processing Rubber      Designing With Rubber      Selecting / Specifying Rubber      Quality In Rubber      Rubber Directory      Health & Safety      Measuring Properties      Glossary of Terms          A-B          C-D          E-G          H-O          P-S          T-Z      Request A Copy Contact Information

C-D   CALENDERING Producing rubber in continuous sheets by processing it through a series of rollers. Harboro does not specialise in this sector of the industry. CLAY Commonly used as an "extender" in rubber. Treated clays reinforce the rubber and are termed "hard" clays. Those which do not provide reinforcement are called "soft" clays. COMPOUND A general word used to describe a particular formulation or "recipe", or as a descriptive term for unvulcanised rubber in general. It is used in such applications as "Compounding ingredients", "Compound no. xyz", etc. COMPRESSION SET The degree to which a rubber does not recover fully to its original state after it has been compressed for a long period of time. (See also "Measurement of Rubber Properties"). CRYSTALLISATION Rubber materials tend to crystallise on standing, resulting in an increase in hardness. This increase is usually small, but can be more significant in the case of some Neoprenes (polychloroprenes). CURATIVES The chemicals involved in curing the rubber, e.g. accelerators, vulcanising agents, activators etc. CURING Also known as vulcanisation, this is the permanent change which the rubber undergoes during moulding. When mixed, rubber compounds are thermoplastic and will melt and deform easily. After curing, the rubber is heat stable.