Seals - Glossary

Benchmark Data - The results of an investigation to determine how competitors and/or best-in-class companies achieve their level of performance.

Backrinding - Defect in which the rubber adjacent to the mold parting line shrinks below the level of the molded product, often leaving the parting line ragged and torn.

Backringing - Distortion at the mold parting line usually in the form of wrinkles, folds, tears or indention's. In severe cases may cause over-all dimensional changes.

Baffle Rings - A ring used to slow the flow of fluids along a shaft.

Ball Valve Seats - A teflon ring shaped to fit against the ball in a flow control valve.

Batch - The product of the one mixing operation in an intermittent process.

Bearings - A machined or molded plastic ring used as a guide ring or wear ring in a hydraulic cylinder.

Bearing Seals - A seal ring made to snap-fit into a ball, roller or spherical bearing to exclude dust, dirt or trash.

Bellows - A corrogated rubber or plastic piece which can stretch with a shaft to keep the shaft clean.

Belts - A v-belt, flat belt or drive belt made from plastic or rubber.

Bias Angle - (1) Acute angle between the direction of the cut and the diameter of the wrap in the production of wrapping for hose; (2) Acute angle between the direction of the cut and the direction of the cords in the production of fabric plies.

Bill of Material - Total list of all components/materials required to manufacture the product.

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

Bloom - A liquid or solid material that has migrated to the surface of a rubber, thereby changing appearance. Sometimes confused with surface dust.

Bloom - The coating or efflorescence of sulfur, wax or oilier ingredients of vulcanized rubber, which may gradually appear on the surface of some rubber articles. Bloom depends on the solubility of the substance in the rubber.

Bond - The union of materials by use of adhesives, usually used in related parts vulcanized after attaching.

Bonded Seals - A flat steel washer with a rubber sealing ring molded into the center to fit over a bolt to provide a seal.

Bonding Agents - Substances or mixtures of substances that are used for attaching rubber to metal, fabrics or other substrates. Generally the rubber compound is vulcanized by heat in the process. Cyclized rubber or rubber isomers, halogenated rubber, rubber hydrochloride, reaction product of natural rubber and acrylonitrile, polymers containing diisocyanates, are all used.

Brittleness - Tendency to crack when subjected to deformation.

Bronze Piston Bearings - Guide rings or wear rings made from bronze to fit on a piston in a hydraulic cylinder.

Bumpers - A rubber or plastic part used to prevent metal-to-metal contact.

Buna N - A general term for the copolymers of butadiene and acrylonitrile. Typical commercial polymers are Hycar and Paracril.

Buna S - A general term for the copolymers of butadiene and styrene.

Bushing - A rubber or plastic spacer to provide a wear surface around a shaft.

Butadiene - CH2=CH-CH=CH2. A gaseous hydrocarbon of the diolefin series, boiling at 5~C. Also known as erythrene, divinyl, pyrollylene, Polymerizable to a synthetic rubber, polybutadiene. Butadiene is the chief raw material for making the synthetic rubbers today. Co polymerized with styrene it yields SBR or GR-S; with acrylonitrile the various Buna N or nitrile synthetic rubbers are obtained.

Butt Joint - Joining two ends of material whereby the junction is perpendicular to the ID of an O-ring.

Butyl - A synthetic rubber of the polybutene type exhibiting very low permeability to gases.

Butyl Rubber - A copolymer of isobutylene and isoprene, polymerized almost instantaneously in methyl chloride with aluminum chloride at about ñ140F. Butyl is resistant to ozone and the action of many other corrosive chemicals. Butyl rubber is resistant to permeation by gases.