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. |
