Glossary
Accelerated Aging:
Simulated aging designed to predict the performance of an adhesive after natural aging, typically by using heat, UV radiation and moisture alone or in combination.
Acrylic Adhesive:
Adhesive made from acrylic monomers that have been polymerized. They have good resistance to UV radiation, plasticizer and extreme temperatures.
Bloom:
A coating or efflorescence creating a discoloration or change in appearance of the surface of a rubber product caused by the migration of a liquid or solid to the surface. Examples: Sulfur Bloom, Wax Bloom. Not to be confused with dust on the surface from external sources.
Blowing Agent:
Mixed with a rubber compound, this material decomposes when heated to form the gases that create sponge rubber.
Cellular Rubbers:
Rubber products that contain cells or small hollow receptacles. The cells may either be open or interconnecting or closed and not interconnecting.
CI:
The abbreviation for cloth-inserted, indicating a sheet of rubber containing one or more plies of fabric covered with rubber.
Closed Cell:
A cell totally enclosed by its walls and hence not interconnecting with other cells.
Compound:
An uncured mixture of a rubber polymer and other ingredients (fillers, vulcanizing agent, etc.).
Compression Set:
The deformation which remains in rubber after it has been subjected to and released from a specific compressive stress for a definite period of time at a prescribed temperature. Compression set measurement is for the purpose of evaluating creep and stress relaxation properties of rubber.
Conformability:
The ability of an adhesive tape to mold itself to the shape of an object without wrinkling or creasing.
Creep Relaxation:
In a flange gasket, loss of stress accompanied by constantly decreasing compressed thickness. This type of relaxation is encountered in bolted flange joints.
Crosslinked:
The establishment of a chemical bond between the molecular chains of a given polymer, thereby enhancing physical properties.
Density:
The weight per unit volume of a material – usually expressed in PCF (pounds per cubic foot).
Double-coated:
Tape with adhesive on both sides.
Durometer:
An instrument for measuring the indentation hardness of rubber; also, sometimes used as a synonym for hardness.
Elastomer:
A macromolecular material which, in the vulcanized state, at room temperature can be stretched repeatedly to at least twice its original length and which, upon release of the stress, will immediately return to approximately its original length.
Elongation:
An increase in length expressed numerically as a fraction or percentage of the initial length.
Expanded Rubber:
Cellular rubber having closed cells made from a solid rubber compound.
Gasket (Mechanical):
A deformable material clamped between essentially stationary faces to prevent the passage of matter through an opening or joint.
Die-cutting material so that it stays in roll form. The finished pieces are easily peeled from the release liner.
Laminate:
Product made by bonding together two or more layers of like, or unlike materials.
Liner Side:
The adhesive side covered by the release liner.
Mils:
Thousandths of an inch.
Monomer:
A simple chemical compound that enters into the production of a polymer.
Open Cell:
A cell not totally enclosed by its walls and hence interconnecting with other cells.
Pattern Coating:
Adhesive applied in patterns in the machine direction causing alternating bands of adhesive and non-adhesive areas.
Plasticizer:
A material which, when incorporated in rubber or a polymer, will change its hardness, flexibility, process-ability and plasticity.
Polymer:
Material made from chains of identical molecules (monomers). The basis of most plastics and adhesives.
Pressure Sensitive:
Adhesive that can be applied to a substrate by using light pressures.
Release Liner:
Coated paper applied to the adhesive to protect it until ready for use.
Removable Adhesive:
Adhesive that can be removed from a surface without leaving a residue.
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 azeotrope. A rubber in its modified state, free of diluents, retracts within 1 minute to less than 1.5 times its original length after being stretched at room temperature (18 to 29oC) twice its length and held for 1 minute before release.
Rubber Based Adhesive:
Made from natural and synthetic rubber compounds. They have excellent initial tack but low temperature and aging resistance.
Silicone Adhesive:
Adhesives made from silicone polymers that have excellent high temperature resistance.
Sponge Rubber:
Cellular structure produced by adding gasifying substance to rubber compound, expanding and curing in heated mold. Cells may be open (interconnecting) or closed.
Surface Energy:
Characteristic of a substrate surface affecting bonding of an adhesive. The higher it is, the better an adhesive bonds. Can be increased by Corona treatment.
Tack:
The stickiness of a tape.
Tensile Strength:
The maximum tensile stress applied while stretching a specimen to rupture.
Thermoplastic Rubber:
Rubber that does not require chemical vulcanization and will repeatedly soften when heated and stiffen when cooled; and which will exhibit only slight loss of its original characteristics.
Thermosetting Rubber:
Chemically vulcanized rubber that cannot be remelted or remolded without destroying its original characteristics.
Transfer Tape:
An unsupported adhesive on a liner.
UL94:
Underwriters Laboratory's rating for flame spread.
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.
Water Absorption:
Measurement of water absorbed by flexible cellular materials during submersion in water under pressure.