Polyethylene is produced from the polymerisation of ethylene molecules which, in turn have been produced from thermoplastic fibrous raw materials. This material can reach a high degree of rigidity through being interlaced with itself. The melting and fusion points lie relatively low which result in good thermal welding properties. The other excellent properties are the low density – lower than water - with a high chemical resistance. Water and moisture are not absorbed and resistance to environmental effects, micro-organisms and insects is very good. The sun’s rays lead to degradation and thus to disintegration. Recycling is mostly done thermically.