Page 17 - ALFAGOMMA English Katalog

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17
The chemical guide in this section is offered as a general indication of the compatibility of the various materials used in ALFAGOMMA hose with the chemicals
and fluids listed. The basis for the ratings in this guide include actual service experience, the advice of various polymer suppliers, and the considered opinion
of our rubber chemists. When in doubt, a sample of the compound should always be tested with the particular chemical it is to handle. Some of the variables
that come into play in the resistance of a compound to chemical attack are:
1. Temperature of the Material Transmitted:
Higher temperatures increase the effect of chemicals on rubber compounds. The increase varies with the polymer and the chemical. A compound
quite suitable at room temperature might fail very quickly at higher temperatures.
2. Service Conditions:
A rubber compound usually swells when exposed to a chemical. With a given percent of swell, a hose tube may function satisfactorily if the hose is in
a static condition, but fail quickly if the hose is subject to flexing.
3. The Grade or Blend of the Rubber Compound:
Basic rubber polymers are sometimes mixed or blended together to enhance a particular property for a specific service. The reaction to a particular
chemical blend of polymers may, therefore, be somewhat different from the reaction to the single ones. When in doubt, a sample of the compound
should always be tested with the particular chemical it is to handle.
COMMON NAME
ASTM
Designation
D1418-93
COMPOSITION
GENERAL PROPERTIES
Natural rubber
NR
Isoprene rubber
Excellent physical properties, including abrasion resistance. Not oil
resistant.
SBR
SBR
Styrene-butadiene rubber
Good physical properties, including abrasion resistance. Not oil
resistant.
Butyl rubber
IIR
Isobutene-isoprene rubber
Very good weathering resistance. Low permeability to air. Good
physical properties. Poor resistance to petroleum based fluids.
EPDM
EPDM
Ethylene-propylene-diene-
terpolymer
Good general purpose polymer. Excellent heat, ozone and
weathering resistance. Not oil resistant.
Cross linked polyethylene
XLPE
Cross linked polyethylene
Excellent resistance to most solvents, oils and chemicals. Do not
confuse with chemical properties of standard polyethylene.
Ultra high molecular weight
polyethylene
UHMWPE
Ultra high molecular weight
polyethylene
Excellent resistance to most solvents, chemicals and hydrocarbons.
Excellent abrasion and wear resistance. Inert and suitable for food
contact. Do not confuse with chemical properties of standard
polyethylene.
Teflon/Fluorocarbon resin
PTFE
Polytetra-fluoroethylene
Excellent chemical and solvent resistance. Inert to most materials.
Smooth anti-adhesive surface, easy to clean.
Nitrile rubber
NBR
Acrylonitrile-butadiene
rubber
Excellent oil resistance. Good physical properties.
Neoprene
CR
Chloroprene rubber
Excellent weathering resistance. Flame retardant. Good oil
resistance. Good physical properties.
Hypalon®
CSM
Chloro-sulfonated
polyethylene
Excellent ozone, weathering and acid resistance. Good abrasion and
heat resistance. Can be compounded for good oil resistance.
Polyurethane
AU
Polyester urethane
Excellent abrasion and wear resistance. Not resistant to hydrolysis.
Viton
FKM
Fluorocarbon rubber
Excellent high temperature resistance, particularly in air or oil. Very
good resistance to chemicals.
GENERAL CHEMICAL RESISTANCE OF ALFAGOMMA HOSE COMPOUNDS
Chemical guide