Rubber & Sealing Glossary 

A

• Abrasion Resistance — The ability of rubber to resist surface wear caused by friction.
• Accelerator — A chemical added to rubber compounds to speed up vulcanization.
• Acid Resistance — The capability of a material to withstand acidic environments.
• Adhesion — The bonding strength between rubber and another material.
• Aflas® — A fluoroelastomer resistant to steam, chemicals, and amines.
• Aging — The deterioration of rubber properties over time.
• Air Leakage — The escape of air through or around a seal.
• Ambient Temperature — The surrounding environmental temperature.
• ANSI — American National Standards Institute.
• Anti-Extrusion Ring — A support ring used to prevent seal extrusion under pressure.
• ASTM — ASTM International standards organization.
• Axial Seal — A seal functioning parallel to the shaft axis.

B

• Backup Ring — A rigid ring used with O-rings to prevent extrusion.
• Barrel Face Seal — A curved sealing interface used in hydraulic systems.
• Base Polymer — The primary elastomer in a rubber compound.
• Batch Mixing — The process of blending rubber ingredients in batches.
• Bearing Isolator — A device preventing contamination from entering bearings.
• Brittleness — The tendency of rubber to crack or break.
• Buna-N (NBR) — Nitrile rubber known for oil resistance.
• Burst Pressure — Maximum pressure a seal can withstand before failure.

C

• Chemical Resistance — Ability to resist degradation from chemicals.
• Clamp Load — The compressive force applied to a gasket.
• Closed Cell Foam — Foam structure with sealed gas pockets.
• Coefficient of Friction — Measurement of surface friction.
• Cold Flexibility — Ability to remain flexible at low temperatures.
• Compression Set — Permanent deformation after compression.
• Conductive Rubber — Rubber capable of conducting electricity.
• Creep — Gradual deformation under stress.
• Cross-Section — The thickness profile of a seal or O-ring.
• Cure Time — Time required for vulcanization.
• Custom Molded Rubber — Rubber products made to specific designs.

D

• Deflection — Amount of deformation under load.
• Diaphragm Seal — Flexible membrane used for sealing pressure systems.
• DIN Standard — German industrial standard.
• Double Acting Seal — Seal effective in both pressure directions.
• Durometer — Measurement of rubber hardness.
• Dynamic Seal — Seal used between moving surfaces.

E

• Elasticity — Ability to return to original shape after deformation.
• Elastomer — Polymer with elastic properties.
• Elongation — Stretchability before breaking.
• EMI Shielding — Protection against electromagnetic interference.
• EPDM — Ethylene Propylene Diene Monomer rubber.
• Extrusion — Seal material forced into clearance gaps under pressure.

F

• Face Seal — Seal between flat mating surfaces.
• FDA Grade Rubber — Rubber approved for food contact.
• FKM — Fluoroelastomer with high chemical resistance.
• Flange Gasket — Gasket installed between pipe flanges.
• Flash — Excess material remaining after molding.
• Flat Gasket — Flat sealing component between surfaces.
• Fluid Compatibility — Suitability of rubber with certain fluids.
• Friction Wear — Material degradation due to rubbing.
• Fuel Resistance — Ability to resist fuel exposure.

G

• Gasket — Mechanical seal filling space between surfaces.
• Glass Transition Temperature — Temperature where rubber becomes brittle.
• Gland — Groove where a seal is installed.
• Grease Seal — Seal designed to retain lubricants.

H

• Hardness — Resistance to indentation.
• Heat Aging — Property changes after heat exposure.
• High Pressure Seal — Seal designed for elevated pressure systems.
• Hydraulic Seal — Seal used in hydraulic cylinders and systems.
• Hydrolysis Resistance — Ability to resist water-induced degradation.

I

• ID (Inside Diameter) — Inner diameter of an O-ring or seal.
• Inflatable Seal — Seal expanded by air pressure.
• Injection Molding — Rubber molding process using injected material.
• Interference Fit — Tight fit ensuring sealing performance.
• ISO Standard — International Organization for Standardization specification.

J

• Jacketing — Protective outer covering on seals or gaskets.
• Joint Sealant — Material used to seal joints.

K

• Kalrez® — Perfluoroelastomer with extreme chemical resistance.
• Knife Edge Seal — Seal using sharp edge contact for high integrity sealing.

L

• Leak Rate — Amount of fluid passing through a seal over time.
• Lip Seal — Seal with flexible sealing lip.
• Low Temperature Resistance — Ability to function in cold conditions.
• Lubrication — Application of lubricant to reduce friction.

M

• Mechanical Seal — Device preventing fluid leakage around rotating shafts.
• Membrane Seal — Flexible barrier seal.
• Metric O-Ring — O-ring sized according to metric standards.
• Mold Release — Agent preventing rubber sticking to molds.
• Molding Flash — Excess rubber from mold parting lines.

N

• Natural Rubber (NR) — Elastomer derived from latex.
• Neoprene (CR) — Chloroprene rubber resistant to weathering.
• Nitrile Rubber (NBR) — Oil-resistant synthetic rubber.
• Non-Asbestos Gasket — Gasket material without asbestos fibers.

O

• O-Ring — Circular elastomeric sealing ring.
• OD (Outside Diameter) — Outer diameter measurement.
• Oil Resistance — Ability to resist oils and lubricants.
• Outgassing — Release of trapped gases from materials.
• Overmolding — Molding rubber over another substrate.

P

• Packing Seal — Compressible sealing material around shafts.
• Perfluoroelastomer (FFKM) — High-performance chemical-resistant elastomer.
• Permeability — Rate at which gases/liquids pass through material.
• Piston Seal — Seal installed on pistons.
• Platen — Heated press surface in molding.
• Polyurethane (PU) — Durable elastomer with abrasion resistance.
• Pressure Rating — Maximum operating pressure limit.

Q

• Quality Assurance (QA) — Procedures ensuring product quality.
• Quick Connector Seal — Seal used in rapid connection systems.

R

• Radial Seal — Seal operating perpendicular to shaft axis.
• Rebound Resilience — Ability to recover after impact.
• Retaining Ring — Ring holding seals in position.
• Rubber Bonding — Joining rubber to metal or other materials.
• Rubber Compound — Formulated mixture of elastomers and additives.

S

• Shaft Seal — Seal preventing leakage around rotating shafts.
• Shore A Hardness — Common rubber hardness scale.
• Silicone Rubber (VMQ) — High-temperature resistant elastomer.
• Single Acting Seal — Seal effective in one pressure direction.
• Spring Energized Seal — Seal energized by an internal spring.
• Static Seal — Seal between non-moving surfaces.
• Swelling — Expansion caused by fluid absorption.

T

• Tear Resistance — Ability to resist tearing forces.
• Temperature Range — Operational temperature limits.
• Tensile Strength — Maximum pulling force before breaking.
• Thermal Expansion — Size increase due to heat.
• Thermoplastic Elastomer (TPE) — Recyclable elastic polymer.
• Tolerance — Permissible dimensional variation.

U

• U-Cup Seal — U-shaped hydraulic seal.
• Ultimate Elongation — Maximum elongation before rupture.
• Ultra-High Molecular Weight Polyethylene (UHMWPE) — Wear-resistant engineering plastic.

V

• Vacuum Seal — Seal preventing gas leakage under vacuum.
• Vibration Isolation — Reduction of vibration transmission.
• Viton® — Brand name for FKM fluoroelastomer.
• Volume Swell — Increase in rubber volume after fluid exposure.
• Vulcanization — Chemical curing process improving rubber properties.

W

• Wear Resistance — Ability to resist mechanical wear.
• Weather Resistance — Ability to withstand outdoor exposure.
• Wiper Seal — Seal removing contaminants from shafts.
• Working Pressure — Recommended operating pressure.

X

• X-Ring — Four-lobed sealing ring with improved sealing performance.

Y

• Yield Strength — Stress level before permanent deformation.

Z

• Zero Leakage — Ideal condition with no detectable leakage.
• Zinc Oxide — Activator used in rubber vulcanization.