Many industries and industrial sectors have profited from the advantages of radiation crosslinking over the years. The application fields are manifold, for example:
Plastics are becoming ever more important as raw materials for automotive and mechanical engineering, in order to meet the increasing requirements for weight reduction and lower fuel consumption. The materials must withstand high thermal, mechanical and chemical strains if they are used, for example, in the engine compartment or exhaust system. Normally, only expensive high performance plastics and those difficult to process meet this requirement profile.
In the electrical industry, plastics are used due to their good insulating properties and extremely flexible shaping possibilities. In addition, ongoing miniaturization and new production technologies are placing ever higher demands on heat resistance and non-flammability. The lead-free solders commonly used today generate peak temperatures over 250 °C, which normally only high-performance plastics are able to withstand such as LCP, PEEK, PES or PEI.
For years now, radiation crosslinking has ensured that plastics used for the insulation of cables, wires and ducts meet the strict heat and chemical resistance requirements. Well-tried and proven applications, for example, are cables with improved resistance to welding beads or cables and ducts in vehicles that have to comply with the heat resistance requirements of classes C and D (working temperatures of up to 125 °C and 150 °C respectively). Nowadays, energy cables are also successfully radiation crosslinked in order to meet specific safety-relevant requirements, for example, in transportation (rail and goods transport), tunnel construction or offshore industry.
To ensure their usage properties over a long period of time, pipes made from HDPE have been radiation crosslinked for decades now. Of particular importance is their improved creep behaviour at high temperatures and internal pressures. For more than 30 years, many million kilometres of radiation crosslinked pipes – known as PE-Xc pipes – installed around the world have demonstrated their reliability in day-to-day use under difficult conditions.
Heat shrink technology is an important area of application for radiation crosslinked polyolefins and TPE. For example, typical applications are the electrical industry and pipelines, where heat shrink products are used as tubes, foils and moulded parts for the insulation of joints. Through radiation crosslinking, semi-crystalline polymer materials are given a “shape memory” by the selective formation of crosslinking points that mainly arise in the amorphous areas.
Changes caused by energy rich rays such as crosslinking, branching (grafting) or molecular weight reduction can also be used in polymeric raw materials for the precise setting of properties. Examples are the controlled increase in the molecular weight of ethylene co-polymers or the insertion of long-chain branches for polypropylene in order to achieve higher processing viscosities or melt strengths.