High Density Polyethylene is widely used in optical fiber cables as outer sheath material. It is preferred for outer sheath due to its superior high abrasion resistance properties compared to its peer group MDPE, LDPE and LLDPE. HDPE does not allow fungus growth and is known to have competitive resistance to many of the chemicals that may present in soils. Environmental stress cracking resistance of HDPE is also superior that makes it a preferred choice for not only optical fiber cable, but for telecom ducts, joint closures and many other products used in telecom networks.
As the name indicates, HDPE has higher specific gravity than MDPE, LDPE and LLDPE. Optical fiber cable makers need to send specifications to suppliers before buying HDPE. Hence it is necessary for you to understand the basic properties of HDPE, though you may be a non-technical person dealing exclusively for commercial matters. Here we outline some basic things that a typical raw material specification should contain. Let us focus on the properties of HDPE intended for sheathing optical fiber cables.
– The material shall contain uniformly dispersed carbon black of such a quantity that good weather resistance is reached.
– The carbon black shall be of Channel or Furnace type.
– The particle size (diameter) of carbon black shall be less than 20 nm on an average.
– The material shall not generate hydrogen in sufficient quantities to degrade the performance of optical fiber cable transmission.
Requirements:
| S # | Attribute | Value | Test Method |
| 1 | Melt Flow index, 190°C, 2.16 kg | ≤ 10 g/10 min | ASTM 1238 |
| 2 | Oxidation Induction Time, 180°C | ≥ 30 minutes | ASTM D 3895 |
| 3 | Carbon Black Content | 25 ± 0.25 % | ASTM D 1603 |
| 4 | Carbon Black Dispersion | Uniform | ASTM D 3349 |
| 5 | Tensile Strength | ≥ 20 MPa | ASTM D 638 |
| 6 | Elongation at Break | > 400 % | ASTM D 638 |
| 7 | Shore D Hardness | ≥ 60 | ISO R 868 |
Test Certificate: Each incoming delivery/ batch shall be accompanied by a test certificate.
Packing: The material shall be packaged in standard commercial containers or bags, so constructed as to ensure safe transportation.
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