XLPE
In 1973, AEI acquired a licence for a new method of chemically crosslinked polyethylene, which had been recently developed by Midland Silicones, now called Dow. This involved the process of forming links between polyethylene chains with the use of silane molecules and was known as the Sioplas process. The resulting material is commonly referred to as XLPE (crosslinked polyethylene) or PEX-b
In 1974 sufficient work had been undertaken to give the confidence to start manufacturing Sioplas in 1975. The focus at that time was utilising the excellent electrical and di-electric properties of XLPE to use it as insulation for low and medium voltage power cables. In 1980 we entered the hot water pipe market with PEX-b compounds and this has grown to be a major part of our business. Our products have, therefore, been in the field for over 30 years and have demonstrated the long life of these products.
XLPE has uses other than in wire and cable and is now one of the main products used in the manufacture of hot and cold water pipes. Other applications are for heatshrink tubing and for medical and dental applications.
The main effect of crosslinking polyethylene (PE) or other polymer types is to improve their high temperature properties. Cable insulation made from PE with a continuous operating temperature of 70°C can have this improved by up to 125°C when it is crosslinked. Typical power cable insulation designed to operate at 90°C will be made of crosslinked PE. Hot water pipes are made from PE-b and are designed to operate at 10 bar at 95°C.
Other properties that are improved by crosslinking are impact and tensile strength, especially at low temperatures, scratch resistance, and resistance to brittle fracture.
Our experience in this sector has continued to grow and we now offer a wide range of standard and flame retardant compounds based on this Sioplas technology. For a full listing of the halogen free flame retardant grades please click on the HFFR or Wire and Cable buttons. We are sure that there are other applications for this easy to use technology and we would be very interested to hear about these.
Grades Available
Please note that these silane crosslinkable grades are shown as a system with a graft and a catalyst. These are normally used in the ratio of 95:5. The most common catalyst masterbatch is shown in the table but there are others available which helps us to more accurately match your property requirements and processing conditions.
