XLPE Compound For Aerial Buched Cables PP 408-401-P-10040-B

This compound utilizes the system for cross linking of polyethylene developed by DOW Corning and known as Sioplas. It is a three component system comprising a silylated ethylene polymer known as the graft copolymer PP 408, a tin based cross-linking catalyst master batch PP 401 and also a master batch P-10040-B containing lubricant, UV ingredient and suitable grade of carbon black. These three material are normally used in the ratio of 90 parts graft, 5 parts catalyst master batch and 5 parts special black masterbatches. Stored separately, these materials are fairly stable but when mixed and exposed to moisture, cross linking takes place. This system allows the compound to be extruded as a normal thermoplastic which will then attain a high level of cross linking in the processed from. The finished product has all the properties associated with polyethylene cross linked by other methods.

Silane grafted black cross linkable polythylene for over head cables.

Special Characteristics :

A silane grafted crosslinkable polyethylene compound, curable by exposure to moisture, for over head cables and possessing excellent extrudability and stretchability. PP 408 is based on a high molecular weight polymer and has melt index in the range of 0.8 to 1.2. It has been specially developed for over head cables.

Technical Characteristics

Properties- Physical & Mechanical Typical value Unit Test Method
Density 0.93 gm/cm3 ASTM – D- 1505
MFI at 190°C/5 Kg. 1.1 G / 10Min. PPIL

Unaged mechanical properties :

Tensile Strength at Break 19 MPa IEC811
Elongation at Break 550 % IEC811

Mechanical Properties after ageing in Air oven, 168 hr. at 135° C :

Variation in tensile strength +10 % IEC811
Variation on elongation at break -10 % IEC811

Hot set test, 15 min. at 200°C, 0.2 N / mm2 :

Elongation under lord 100 % IEC811
Permanent Set. 5 % IEC811
Note : Tensile Properties are based on the mixture of 90% of PP 408, 5% of PP 401 and 5% of P-10040-B extruded and cured at the temperature of 90°C for a duration of 2.5 hr.
Electrical Properties : Typical value Unit Test Method
Power factor at 50 Hz at 23°C 0.0004 Nil IEC25
Dielectric constant 2.3 --------- IEC250
Volume Resistivity at 23°C 2.4*1015 Ohm.cm IEC502
Dielectric Strength 25 KV/mm IEC243

Recommended Extrusion Conditions :

Extruder :

Thermoplastic extruders will process PPIL Sioplas – type compound particularly if the screw is suitable for polyethylene extrusion. An extruder having L/D ratio of at least 20 and compression of 3 : 1 is recommended.

Extrusion temperature conditions : As a guide the following temperature profile is recommended :
Zones 1 2 3 4 5 6
Temperature 150°C 160°C 170°C 180°C 190°C 200°C
*This profile may vary depending on extruder type design and out put.

Screw water temperature :

60°C – 70°C
Screens :
30,80, 30 (mesh aperture per linear inch)
Head And Tool Design :
The head and tools should be so designed to allow streamline flow without the possibility of stagnation of material. To obtain optimum physical properties in the case of tubing tools, it is generally recommended that a draw down ration not greater than 3:1 should be used .

Crosslinking Or Cure :

Curing can be done in the following ways :
- By immersion in hot water 90-95°C
Following factors are important for cure :
• Total Volume of the material.
• Diameter and packing of roll.
• Catalyst percentage may be adjusted 3.5% depending on cure characteristics.
Master Batch :

It is recommended that the catalyst master batch and black master batch be thoroughly dried before usage at 70°C for 4 hrs. at a depth not greater than 5 cm. ( Base of try should have perforation ) or dehumidified dryer should be used.

Storage :
Store under cold and dry conditions for best results.
Packaging :
Moisture resistant high density carboy containing 25 kg

This information is to the best of our knowledge. The values of different parameters and operating conditions listed above are guidance only and should not be used for drawing specifications. The results & operating conditions may vary depending on methods of test and manufacturing / testing equipments.