Page 246 - belden

TE CH N I C A L INF O RM A T I O N 246

Insulations and Jackets
Overview

E-CTFE Polypropylene (Solid and Foam) a specific application. Some formulations are
suitable for -55°C minimum, while others are
Thermoplastic fluoropolymer material with Similar in electrical properties to
suitable for 75°C maximum.
excellent chemical resistance, electrical polyethylene. This material is primarily
properties, thermal characteristics, and used as an insulation material. Typically,
Silicone
impact resistance. The temperature rating it is harder than polyethylene. This makes
is -70°C to 150°C. it suitable for thin wall insulations. UL This is a very soft insulation which has a
maximum temperature rating may be 60°C, temperature range from -80°C to 200°C.
Neoprene 80°C or 105°C. The dielectric constant is 2.25 It has excellent electrical properties plus
The temperature range of this material for solid and typically 1.55 for foam designs. ozone resistance, low moisture absorption,
weather resistance, and radiation resistance.
can vary from -55°C to 90°C. The actual
Polyurethane It typically has low mechanical strength and
range would depend on the formulation
poor scuff resistance.
used. Neoprene is both oil-resistant and This material is used primarily as a cable
sunlight-resistant, making it ideal for many jacket material. It has excellent oxidation,
FEP/TFE
outdoor applications. The most stable oil, and ozone resistance. Some formations
colors are black, dark brown, and gray. The also have good flame resistance. It is a hard This material has excellent electrical
electrical properties are not as good as other material with excellent abrasion resistance. properties, temperature range, and chemical
insulation materials. Because of this, thicker It has outstanding “memory” properties, resistance. It is not suitable where subjected
insulation should be used. Typical designs making it an ideal jacket material for to nuclear radiation and does not have
where this material is used are lead wire retractile cords. good high voltage characteristics. FEP is
insulation and cable jackets. extrudable in a manner similar to PVC and
PVC polyethylene. This means that long wire and
Polyethylene (Solid and Foamed) cable lengths are available. TFE is extrudable
Sometimes referred to as vinyl or
in a hydraulic ram type process. Lengths are
A very good insulation in terms of electrical polyvinylchloride. Extremely high or low
limited due to amount of material in the
properties. Low dielectric constant, a stable temperature properties cannot be found
ram, thickness of the insulation, and preform
dielectric constant over all frequencies, in one formulation. Certain formulations
size. TFE must be extruded over a silver- or
very high insulation resistance. In terms of may have -55°C to 105°C rating. Other
nickel-coated wire. The nickel- and silver-
flexibility, polyethylene can be rated stiff to common vinyls may have -20°C to 60°C.
coated designs are rated 260°C and 200°C
very hard, depending on molecular weight There are many formulations for the
maximum, respectively. The cost of FEP/TFE
and density — low density being the most variety of different applications. The many
is approximately 8 to 10 times more
flexible, with high-density, high-molecular varieties of PVC also differ in pliability and
per pound than PVC compounds.
weight formulation being very hard. electrical properties. The price range can
Moisture resistance is rated excellent. Black vary accordingly. Typical dielectric constant
ETFE
and specially formulated colored versions values can vary from 3.5 to 6.5.
have excellent weather resistance. The Fluorocopolymer thermoplastic material
dielectric constant is 2.3 for solid insulation Rubber having excellent electrical properties, heat
and typically 1.64 for foam designs. The description of rubber normally includes resistance, chemical resistance, toughness,
radiation resistance, and flame resistance.
Flame retardant formulations are available natural rubber and SBR compounds. Both of The temperature rating is -65°C to 150°C.
with dielectric constants ranging from about these materials can be used for insulations
1.7 for foam flame retardant to 2.58 for and jackets. There are many formulations of
solid flame retardant polyethylene. these basic materials. Each formulation is for

Fo r m o r e i n fo r m at i o n, c o n t a c t Be ld e n Te ch n i ca l S u ppo r t : 1- 8 0 0 - B E L D E N -1 • www. b e l d e n . c o m