Glossary of Terms (A-Z)

AASHTO

The American Association of State Highway and Transportation Officials is a non-government entity which sets standards and guidelines for highway construction and transportation protocols in the United States. Its purpose is to support states in efficiently and safely moving people and goods.

 

Abrasion Resistance

Withstanding surface loss of a material due to frictional forces.

 

Age Resistance

Ability of a material to resist deterioration caused by aging.

 

Aging

The change in physical and chemical characteristics of an elastomer that has been exposed to a particular environment over time.

 

AMS

SAE Aerospace Material Specifications are utilized worldwide in the design and production of aircraft components and systems. AMS documents are standardized procurement documents designed to speed the process of delivery, reduce cost, and to reduce the number of individual company and government specifications. The use of AMS is voluntary.

 

Antioxidant

Any organic compound that slows the process of oxidation

 

Antiozonant

Any substance that slows the severe oxidizing effect of ozone on elastomers. Exposure to ozone typically causes surface cracking in many rubbers

 

ASTM International

Formerly known as the American Society for Testing and Materials, ASTM International is a global standards organization that develops international standards for materials, products, systems, and services. The current Annual Book of ASTM Standards has 15 sections covering subjects ranging from steel, plastic, & rubber to electrical, water, nuclear and more.

 

Bloom

Liquid or solid material that has migrated to the surface of a rubber and generally changes the surface appearance.

 

Butyl Rubber

Butyl Rubber is a copolymer of isobutylene and a small percentage of isoprene. Butyl rubber is impermeable to air and is used in applications requiring airtight rubber. Butyl rubber is use in many applications such as tire inner tubes, adhesives, fuel additives, caulks, sealants, and more.

 

Cloth–Inserted

Fabric re-enforced sheet rubber enhances dimensional stability and is typically used in applications with high compression loads.

 

CNC Router

A computer numerical control router is a computer-controlled cutting machine related to the hand-held router used for cutting various hard materials, such as wood, composites, aluminum, steel, plastics, glass, rubber and foams.

 

Compression Molding

A molding process in which the uncured rubber compound is placed directly into the mold cavity, and compressed to its final shape by the closure of the mold

 

Compression Set

The permanent deformation experienced by a rubber material when compressed for a period of time. The term is commonly used in reference to a test conducted under specific conditions wherein the permanent deformation, expressed as a percentage, is measured after a prescribed period of time. A low compression set is desirable in molded rubber parts such as seals and gaskets, which must retain their dimensions to maintain an effective seal.

 

Co–Polymer

A polymer made of two different monomers. For example, SBR is a rubber co-polymer and is made up of the monomers Styrene and Butadiene.

 

Cure

An irreversible process during which a rubber compound through a change in its chemical structure (cross–linking, for example), 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. Cure and vulcanization are interchangeable terms as they share the same definition.

 

Die Cutting

Die cutting is the general process of using a die to shear webs of materials such as rubber, fiber, foil, cloth, paper, corrugated fiberboard, chipboard, paperboard, plastics, pressure-sensitive adhesive tapes, foam, and sheet metal.

 

Durometer

Instrument for measuring the indentation hardness of rubber.

 

Elasticity

A rubber’s ability to return to its original size and shape after removal of the stress causing deformation such as stretching, compression, or torsion. It is the opposite of plasticity. The term elasticity is often loosely employed to signify the “stretchiness” of rubber.

 

Elongation

General referred to in terms of tensile (pull apart) testing, elongation is the increase in length of a test specimen, expressed as a percentage of its original (unstretched) length… relative to a given load at the breaking point.

 

Extrusion

The process in which an uncured rubber compound is pushed through a die of a desired cross-sectional shape or profile. 

 

Gasket

A shaped piece of rubber that seals the junction between two surfaces. Often found in engines, pipes, tanks, valves and a multitude of other devices and applications, rubber gaskets may be molded, extruded, spliced, or die cut from sheet materials.

 

Hardness

A measurement of the resistance to penetration of a rubber sample by an indenter. High values indicate harder materials while low values indicate softer materials.

 

Injection Molding

A molding method in which a rubber or plastic material is heated and forced under pressure into the mold cavity.

 

Kiss cutting

During the kiss-cutting process, the perimeter of each part is cut by a sharp metal die or laser beam, but the cut does not penetrate the part’s backing material (liner).

 

Laser cutting

Laser cutting is a precise method of cutting a design from a given material using a CAD file to guide it.

 

Lathe cutting

A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.

 

Mooney Viscosity

A measure of the plasticity of a polymeric compound determined in a Mooney sheared disc viscometer.

 

Modulus

A measure of resistance of a material to deformation. It is measured by the force required to reach a predetermined compression or extension

 

Oil Resistant

Ability of vulcanized rubber to resist swelling and other detrimental effects of exposure to various oils.

 

Plasticize

To soften a material and make it plastic or moldable, either by means of a plasticizer or application of heat.

 

Plasticizer

A chemical agent added to the rubber compound batch mix to soften the elastomer for processing, as well as to improve physical properties of the compound product (i.e. increase elongation, reduce hardness, improve tack)

 

Polymer

Many monomer units chemically linked together in repeating structural units. Rubber polymers available at DRC include: Neoprene, Butyl, EPDM, Nitrile (Buna–N), Natural Rubber, SBR and Silicone.

 

Polymerization

Process of linking two or more molecules to form a new molecule having different properties.

 

Preco

Preco is the brand name of DRC’s automated die-cutting machine. This machine is able to die-cut large quantity with high pace.

 

PSA 

Pressure Sensitive Adhesive.

 

Resilience

The capability of returning to original size and shape after deformation

 

Roll Slitting

Roll slitting is a shearing operation that cuts a large roll of material into narrower rolls.

 

Rubber

A common name for both naturally occurring and synthetically made elastomers

 

Scorching

Premature curing of compounded rubber stock during processing or storage, with the potential for adversely affecting material flow and plasticity during subsequent shaping and curing processes.

 

Shore Hardness

A durometer or hardness test that measures the depth of an indentation in the material created by a given force on a standardization presser foot. The two most common scales are ASTM D2240 type A and type D scales. The A scale is for softer plastics, while the D scale is for harder ones.

 

Synthetic Rubber

An elastic substance produced from monomers such as butadiene, styrene and isoprene. Because of superior performance (tread wear, resistance to groove cracking, lower cost) synthetic rubbers have largely replaced natural rubber.

 

Tear Resistance

Resistance to the growth of a cut in the seal when tension is applied

 

Tensile Strength

The force required to rupture a sample of stated geometry

 

Thermoplastic

A material which when thermally processed undergoes a reversible phase change to become plastic and capable of being molded to a desired shape. Upon cooling, the material reverts to its original properties

 

Thermoplastic Elastomer (TPE)

A material which combines the processing characteristics of a plastic but displays rubber-like properties upon completion of processing

 

Thermoset

A material, either an elastomer or plastic, which when thermally processed undergoes an irreversible chemical reaction to achieve its final material state

 

Toughness

Property of resisting fracture or distortion. Usually measured by impact test, high impact values indicating high toughness

 

TPE

Thermoplastic Elastomer combines the rubber-like performance of elastomers with the processing advantages of plastic. Scrap material can be recycled without significant loss in physical properties, unlike thermoset materials.

 

Waterjet cutting machine

A waterjet cutter is an industrial tool capable of cutting a wide variety of materials using a very high-pressure jet of water, or a mixture of water and an abrasive substance to cut hard materials such as metal or granite.

 

Viscosity

The measurement of the resistance of a material to flow under stress

 

Vulcanization

An irreversible process during which a rubber compound through a change in its chemical structure (cross–linking, for example), 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. Cure and vulcanization are interchangeable terms as they share the same definition.