| Abrasion Resistance - The
ability of a material to withstand the loss of
surface due to friction. |
| Accelerated Aging -
Simulated aging tests used to predict the
life-cycles of an adhesive undergoing natural aging.
Test normally use heat, UV radiation and moisture
alone or in combination. |
| Acid Resistant - Withstands
the corrosive action of acids. |
| Acrylic Adhesive - Plastic
glue. Offers good resistance to UV radiation and
extreme temperatures. |
|
AMS
- American Military Standards |
| Anti-Stick
Coatings -
Surface treatments that prevent gasket materials
from adhering to flanges. |
| Anti-Vibration Mounts -
Usually rubber pieces used as padding between a
motor and the frame (for example) preventing
vibration transfer. Dampeners. |
|
ASTM -
American Society for Testing and Materials. Visit
ASTM.org. |
|
Beater Additives - A water-based process
used to make gasket material where the elastomer is chemically deposited onto the fibers
and fillers. |
|
Binder - the elastomer (or rubber) used in gasket material. |
| Bloom - An efflorescent
coating creating a discoloration or visual change on
the surface of a material. Sometimes caused by the
migration of a substance to the surface of product,
it can also be normal in some organic materials.
Sulfur or wax bloom. |
| Blowing Agent - Mixed with a
compounded into many formulations, these ‘blowing
agents’ form gases to create a cellular structure,
such as sponge rubber. |
| Bumpers - A rubber or
plastic part used to cushion items on usually sudden
contact. As small as rubber 'bumps' on a display
case to dock bumpers and fenders for ships. |
|
Butyl - Isobutylene isoprene-IIR. Produced by copolymerizing isobutylene with
isoprene. These rubbers exhibit excellent
impermeability to gases, excellent dielectric
properties, good tear-resistance, good aging at
elevated temperatures, good chemical stability.
See
Butyl Sheet - |
| Cellular, Cellular Rubbers -
Rubber or other product evidencing a cellular
structure. Cells may have an open / interconnecting
structure or closed, not connecting features. |
|
Chemical Resistance - Material's degradation resistance to the fluid being sealed.
|
| CI, Cloth-Inserted -
Material, (typ. rubber) containing one or more plies
of fabric covered with rubber, synthetic or other
coverings. Cloth inside. See
CI
Neoprene Sheet - |
| Closed Cell - Cells
demonstrating a separate, not interconnecting
structure with other cells. Isolated chambers. As
opposed to ‘open-cell.’ See
Closed
Cell Sponge - |
| Compound - An raw mixture of
a ingredients – typically referring to polymers,
rubber and other synthetic fillers, vulcanizing
agents, etc. |
| Compression Set - The
deformation remaining in the material 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. |
| Coefficient of Expansion -
1) Linear: The ratio of the change in length per
degree to the length at 0°
Celsius. 2) Surface: Two (2) times the linear
coefficient. 3) Volume: The coefficient of volume
expansion (for solids) is three (3) times the linear
coefficient. The coefficient of volume expansion for
liquids is the ratio of the change in volume per
degree to the volume at 0°
Celsius. |
|
Compressibility -
The percent of loss of thickness when subjected to a given
load applied by a disc of a given diameter for a
specified short time and at a specified temperature.
Defined by
ASTM F-36 test procedures. |
| Conformability - The ability
of a material to conform, especially to a mold. |
| Creep Relaxation - The loss
of stress accompanied by constantly decreasing
compressed thickness. This type of relaxation is
typical in bolted flange joints. |
| Density - Weight per unit
volume of a material – usually expressed in PCF
(pounds per cubic foot). |
| Durometer - An instrument
that measures the hardness of rubber through
indentation.
Durometer Hardness - an arbitrary numerical value measuring the resistance to
indentation of the blunt point of a durometer. |
| Elastomer - A wide range of
materials exhibiting extraordinary properties of
elasticity and compressive performances. |
| Elongation - An increase in
length shown as a fraction (or percentage) of the
original length. |
|
EPDM - Ethylene Propylene Dienemethylene Terpolymer. A polymer resulting from
a sulfur cure system. Known for resistance to
weathering and high temperatures. EPDM rubbers are
use extensively in outdoor applications. They will
withstand all types of weather as we;; as sunlight,
ozone and oxidants. Excellent resistance to animal
and vegetable oils, water, steam, oxygenated
solvents. |
| Expanded Rubber - Closed
cell material produced from a solid rubber compound. |
| Gasket (Mechanical) -
Usually a deformable material clamped between
stationary faces to effectively seal the coupling.
Gaskets are used to guard against the passage of
liquids, gases, etc. |
| Hand - The subjective or
relative ‘feel’ of a material, indicating
pliability, texture and even desirability of a
material for tactile contact. |
| Kiss-Cut - Die-cutting
material so that it remains attached in sheet or
roll-form. Often provided on a release liner to
accommodate use. |
| Laminate - Product made by
bonding together two or more layers or sheets
together, often under high-pressure / temperature
combinations. |
| Mils - Measurements in
thousandths of an inch. |
| Modulus - The ratio of
stress to strain. In the physical testing of rubber,
the load necessary to produce stated percentage of
elongation, compression or shear. |
| Monomer - A chemical
compound used in the production of polymers. |
|
Natural Rubber - Natural Polyisoprene-NR. Excellent properties, outstanding
performance in many mechanical applications. High
resilience, high tensile and tear properties and
excellent resistance to cold flow. When exposed to
petroleum derivatives, ozone, sunlight and oxygen,
natural rubber and its heat aging properties are
inferior to many synthetics. See
Natural Gum Rubber Sheet - |
|
Neoprene - Chloroprene-CR. A polymer chloroprene rubber known resistance to oil,
gasoline, sunlight, ozone and oxidation. An
excellent general purpose polymer for most
applications. See
Neoprene Sheet - |
|
Nitrile - Butadiene Acrylonirile, Buna N.
A copolymer of Butadiene and Acrylonitrile. Most
nitrile compounds have a relatively high acrylo
content, making them exceptionally resistant to
petroleum-base oils and hydrocarbon fuels over a
temperature range of -40F to +250F. |
| Open Cell - A cell not
totally enclosed by its walls connecting with other
cells. Non-isolated chambers. As opposed to
‘closed-cell.’ |
| Pattern Coating - Adhesive
applied in alternating bands of adhesive and
non-adhesive. |
| Plasticizer - A material
incorporated in rubber or polymer formulations will
alter hardness, flexibility, plasticity and other
properties. |
| Polymer - Chains of
identical molecules – monomers – that form the basis
of most plastics and adhesives. |
| Pressure Sensitive -
Adhesive that can be applied to a substrate by using
(typ) light pressures. |
| Release Liner - Coated paper
applied to products, often adhesive coated, to
protect them until ready for use. |
| Removable Adhesive -
Residue-free adhesive, easily removed from a
surface. |
| Rubber - A bouncy little
material that recovers from large deformations
quickly and forcibly. It is essentially insoluble -
but can swell - in boiling solvent, such as benzene,
methyl ethyl ketone, etc. See Red
Rubber - |
| Rubber Based Adhesives -
Made from natural and/or synthetic compounds.
Excellent initial tack but low temperature and aging
resistance. |
|
SBR
(Rubber)
- Styrene Butadiene, Buna S, GRS). A synthetic
copolymer composed of styrene and butadiene. Used
more often than any other synthetics produced. SBR
has similar resistance to solvents and chemicals as
natural rubber. It can be bonded to a wide range of
materials. |
|
Silicone - Offers a wide range of operating temperatures from -80°F to
+400°F. Excellent dry heat resistance. Silicone compounds are
inert and comply to
ASTM, military, and FDA specifications. For food, medical,
electrical, and filter manufacturers. Do not use in
dynamic seals because of poor tensile, tear, and
abrasion resistance. |
| Silicone Adhesive - Silicone
polymer based adhesives with excellent high
temperature resistance and elasticity. |
| Sponge Rubber - Cellular
structure produced by adding gasifying substance
(blowing agent) to a compound, curing in heated
molds. |
| Tack - Stickiness. |
| Tensile Strength - The
maximum tensile stress applied while stretching a
material to failure. |
| Thermoplastic Rubber -
Rubber that does not require chemical vulcanization.
Repeatedly softens when heated, stiffens when
cooled. Normally exhibiting only slight degradation
of original characteristics. |
| Thermosetting Rubber -
Chemically vulcanized rubber that can not be
re-melted or re-molded without destroying original
characteristics. |
| UL94 - Underwriter’s
Laboratory’s flame spread rating. |
|
Vulcanization - An irreversible process
causing a (rubber) compound to alter its chemical
structure. Vulcanization typically decreases
plasticity and improves resistance to swelling by
organic liquids. Elastic performance may improve in
the overall and extended range of temperatures. |
| Water Absorption - Tests or
indicators of the amount of water absorbed by
materials during submersion in water, often under
pressure. |
| Young's Modulus - The ratio
of normal stress to corresponding stress or
compressive stresses below the proportional limit of
the material. |
