Rubbers
or Elastomers are mixed with various chemicals in order to
provide the reinforcement and curing ingredients required to produce the physical
properties necessary for the service conditions. A wide choice of basic polymers
(elastomers) is available, and some of these elastomers can be blended or compounded
to obtain different properties.
Sheet rubber applications involve packing, gasketing, and sealing of all types
of material including gases, liquids, and solids. In sealing or separating these
materials, wide range of service conditions, such as temperature and surface
type, may be encountered. It is essential that all of these factors be carefully
considered to assure selection of that grade and type of sheet rubber which
will deliver optimum performance as well as economy.
Rubber
Chart
It is not
the purpose of this table to discuss the compounding ingredients or the methods
of compounding. The comments on different elastomers are limited to the basic
properties.
| ASTM DESIGNATION D-1418-79 | COMMON NAME | GENERAL PROPERTIES |
| ABR | Acrylic | + Excellent resistance to high temperature, oil and air, ozone, and weathering. - Poor low temperature properties. Not recommended for water service. |
| AFMU | Teflon, Kel-F | + Excellent chemical resistance. Excellent high and low temperature properties. |
| AU | Urethane | + Good aging and excellent abrasion, tear, and solvent resistance. - Poor high temperature properties. |
| BR | Butadiene rubber | + Excellent abrasion resistance and low temperature properties. High resilience |
| CPE | Chlorinated- polyethylene | + Excellent ozone and weathering resistance; good heat resistance. Moderate resistance to petroleum-based fluids. |
| CR | Neoprene (Chloroprene) | + Good oil and petroleum based solvent resistance. Good weathering and ozone resistance. Neoprene may be blended with SBR rubber to achieve an economically priced sheet for moderately oil resistant applications. - Poor resistance to degreaser solvents. Content levels of neoprene can vary widely. Application problems may occur when using blended or commercial grades of neoprene sheet of unknown quality levels in contact with oil, solvents and fuels. Where high oil or fuel resistance is required, the fabricator and user need to specify one of the following.
|
| CSM | Hypalon® (a registered Trademark of DuPont) | + Good oil resistance, ozone resistance, heat resistance and weathering resistance. Resists corrosive chemicals. - Tear resistance is fair. Poor resistance to aldehydes, aromatic solvents, esters, and chlorinated solvents. Fair resistance to ketones and ethers. |
| ECO | Hydrin, Herchlor | + Good low temperature properties. Excellent oil and ozone resistance. Fair flame resistance. - Low permeability to gases. |
| EPDM | Ethylenepropylene - diene | + Good low temperature properties. Excellent oil and ozone resistance. Fair flame resistance. - Low permeability to gases. |
| FPM | VITON® fluoroelastomer, a registered trademark of DuPont | + Excellent resistance to heat and oil combinations hot greases found in engines and compressors. Excellent resistance to a wide range of concentrated acids. - High cost of fluoroelastomer may limit usage to extreme applications. Resilience is low and tear strength is limited unless certain compounding steps are taken to improve it. Impact resistance is fair. |
| IIR | Butyl (Isobutene-Isoprene) | + Excellent resistance to acid and alkali. Excellent weathering properties and heat resistance. Excellent electrical resistance. Low permeability to air. - Poor resistance to fuels, solvents, oil and hydrocarbons. Cold weather properties are fair. |
| IR | Isoprene (synthetic) | Similar to natural rubber |
| NBR | Nitrile (butadiene-acrylo-nitrile) based | + Excellent resistance to oils, solvents and fuels. Resistant to a broader range of aromatic hydrocarbons than neoprene. Nitrite may be blended with SBR rubber to achieve an economically priced sheet for moderately oil resistant applications. - Application problems
may occur when using Nitrite of unknown quality levels in extreme oil-resistance
applications or in contact with fuels and solvents. Content levels of
Nitrite can vary widely. Where oil or fuel resistance is required, the
fabricator and user need to specify one of the following:
|
| NR | Natural rubber | + Good gasket material due to excellent physical properties such as resilience, tear strength and wear resistance. Natural rubber is used effectively as sand and shot blast curtain material because of its high abrasion resistance and resilience. - Deteriorates when exposed to oils, fuels, solvents, and hydraulic fluids. Poor resistance to sunlight, ozone and oxygen. |
| Q | Silicone | + Excellent properties
for both hot and cold temperature extremes. Excellent weathering properties
and resists ozone and oxygen attack. Long service life can be expected
at 200° F. to 400° F. - Poor resistance to oils, fuels and hydrocarbons. Fair performance when exposed to acids, alkalis and solvents. Physical properties (tensile, abrasion, tear and cut growth) are fair. |
| SBR | Styrene-butadiene | + Good abrasion resistance and excellent impact and cut-and-gouge resistance. Can be compounded for use as skirtboard rubber, lining rubber, conveyor belt covers, tires and other extremely demanding applications. Used as gasket material and as an economical general-purpose sheet. - Not suited for use with oils, fuels, solvents, or hydraulic fluids. |
