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Basic Technical Data of Thermoplastic
Low-smoke Halogen-free Flame-retardant Sheath Materials
Notes:
The WDZ-H-1, WDZ-H-2 and WDZ-H-3 series refer to thermoplastic low-smoke halogen-free flame-retardant sheath materials for cables. They are produced from halogen-free high polymer as base material and auxiliary materials, such as halogen-free flame retardant, antioxygen and lubricant, after being mixed, plasticized and granulated. They are applicable for sheaths of cables, such as communication cable, control cable, signal cable and power cable. And the maximum temperature of conductor is 90°C.
With excellent flame retardant property, WDZ-H-3 can pass the Class A vertical bundles combustion test in coordination with cable structural design.
I. Basic Performances
Item |
Test Mode |
Unit |
Typical Value |
||
NHLS-1 |
NHLS-2 |
NHLS-3 |
|||
Melt Flow Index (150°C×10kg) |
GB/T3682 |
g/10min |
0.81 |
0.63 |
0.45 |
Density (23°C) |
GB1033 |
g/cm³ |
1.47 |
1.48 |
1.49 |
Tensile Strength |
GB/T1040 |
Mpa |
11.0 |
11.6 |
12.4 |
Elongation at Break |
GB/T1040 |
% |
230 |
212 |
221 |
110°C×168h Variable Rate of Tensile Strength in Thermal Aging |
GB/T2951.2 |
% |
+6 |
-3 |
+7 |
Variable Rate of Elongation at Break |
GB/T1040 |
% |
-17 |
-4 |
-11 |
Low-temperature Impact Embrittlement (-25°C) |
GB/T2951 |
°C |
Pass |
Pass |
Pass |
Low Temperature Tensile (-15°C) |
Pass |
Pass |
Pass |
||
Thermal Stress Crack Resistance |
Failure Rate |
0 |
0 |
0 |
|
Environmental Stress Crack Resistance |
Failure Rate |
0 |
0 |
0 |
|
Dielectric Strength |
GB/T3084 |
Mv/m |
27 |
29 |
26 |
Volume Resistivity (20°C) |
GB/T1040 |
Ω.cm |
3.1×1014 |
3.9×1014 |
1.7×1014 |
Oxygen Index |
GB/T2406 |
% |
35 |
38 |
40 |
Max Smoke Density Dm-with flame |
ASTM E662 |
Ds max |
50 |
53 |
55 |
Max Smoke Density Dm-Nonflame |
E662 |
Ds max |
135 |
147 |
155 |
HCL Emission Value |
mg/g |
0 |
0 |
0 |
|
pH value |
GB/T17650.2 |
5.7 |
5.3 |
5.9 |
|
Toxicity Index |
MES713 |
1.5 |
1.5 |
1.5 |
|
Conductivity |
GB/T17650.2 |
μs/mm |
2.6 |
2.7 |
2.7 |
II. Predrying
Materials may be dried at the temperature of 70°C for 4 hours in case of long term storage. The specific drying temperature and time shall be subjected to the situation that whether materials get damp or situation of moisture level.
III. Processing Technology
Above granular materials can be basically processed with single threaded screw (length-diameter ratio at 18:1 or 25:1). Screws that adopt low compression ratio (2:1 - 3:1) are preferred, and the extrusion equipment shall guarantee precise temperature control performance.
Proposed temperature distribution for extrusion is as follows:
Material sending area: 120-135°C
Central area: 135-140-145°C
Extrusion die / mould area: 150-155°C
Semi-tubing extrusion mould and extrusion mould are all available, and extrusion die may be not equipped with filter screen. Extrusion speed shall be in line with the pulling speed of wires and cables when extruding cable sheath. Sheath shall not be hyperextended in avoidance of influencing [121]its physical and mechanical properties. Relative high temperature shall be maintained in the cooling water tank.
Above processing technologies are just instructive suggestions rather than universal ones. Due to difference of various equipment and other reasons, users need to make appropriate adjustments accordingly to achieve stable extrusion process.
IV. Warehousing and Storage
The product is adopted with outer packing (paper-plastic composite bag) together with inner packing (PE internal lining or aluminum foil in accordance with customer’s demand), with net weight of 25±0.2kg per bag.
The product should be rain-roof, moisture-proof and well packed, not be directly exposed to the sun.
Notes:
Typical values stated in the Basic Performances Form shall not be regarded as the assessment criteria.
Technical indexes herein will be correspondingly adjusted according to relevant market demands without notice.
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