Rubber Term Glossary

A guide to technical rubber manufacturing terms:


Abrasion: the surface loss of material due to frictional forces.

Abrasion Resistance: the resistance of a material to loss of surface particle due to frictional forces.

Blister: a cavity or sac that deforms the surface of a material.

Cell: a single small cavity surrounded partially or completely by walls.

Cellular Material: a generic term for materials containing many cells (either open, closed or both) dispersed throughout the mass.

Cellular Rubbers: a cellular material made of rubber. Cellular rubber products all contain cells or small hollow receptacles. The cells may either be open and interconnecting, or closed and not interconnecting.

Closed Cell: a cell totally enclosed by its walls and hence not interconnecting with other cells.

Collapse: inadvertent densification of a cellular material during its manufacture resulting from breakdown of its cellular structure.

Compound: an intimate mixture of a polymer with all the ingredients necessary for the finished article.

Compression Deflection: PSI to compress lab slab a specified percentage of overall height, normally 25%.

Compression Set: the residual deformation after removal of the force that has subjected the specimen to compression.

Crazing a surface effect on rubber articles characterized by many minute cracks.

Cure: the act of vulcanization. See vulcanization.

Durometer: an instrument for measuring the hardness of vulcanized rubber or plastic. Shore 00 scale is for sponge, Shore A for dense/solid.

Durometer Hardness: an arbitrary numbering scale that indicates the resistance to the indenter point of the durometer. High values indicate harder materials.

Expanded Rubber: Cellular Rubber having closed cells made from a solid rubber compound.

Open Cell: a cell not totally enclosed by its walls and hence interconnecting with other cells.

Ozone Cracking: the surface cracks, checks or crazing caused by exposure to an atmosphere containing ozone.

Post Cure: heat or radiation treatment to which a cured or partially cured rubber is subjected to enhance one or more properties.

Rebound: a measure of the resilience, usually as the percentage of vertical return of a body that has fallen and bounced.

Rubber: a material that is capable of recovering from large deformations quickly and forcibly, and can be, or already is, modified to a state in which it is essentially insoluble (but can swell) in boiling solvent, such as benzene, methyl ethyl, ketone and ethanol-toluene isotope. Set strain remaining after complete release of the load producing the deformation.

Shelf Aging: the time an unvulcanized rubber stock can be stored without losing any of its processing or curing properties.

Shore Hardness: see durometer hardness. Skin a relatively dense layer at the surface of a cellular material.

Sponge Rubber: cellular rubber consisting predominantly of open cells made from a solid rubber compound.

Substrate: a material upon the surface of which an adhesive is applied for any purpose such as bonding or coating.

Tear Strength: the maximum load required to tear apart a specified specimen, the load acting substantially parallel to the major axis of the test specimen.

Tensile Strength: the maximum tensile stress applied during stretching a specimen to rupture.

Vulcanizate: preferably used to denote the product of vulcanization, without reference to its shape or form.

Vulcanization: an irreversible process during which a rubber compound through a change in its chemical structure (for example: cross-linking) becomes less plastic and more resistant to swelling by organic liquids and elastic properties are conferred, improved or extended over a greater range of temperature.

Weathering: the surface deterioration of a rubber article during outdoor exposure, such as checking, cracking, crazing or chalking.

Rubber Term Glossary