Issue link: https://te.mouser.com/i/1349221
HEAT SHRINK TUBING FOR AUTOMOTIVE APPLICATIONS TE AUTOMOTIVE /// WHITE PAPER 4 Technology • Polymer formulation TE Connectivity's Raychem formulations are blends of polymers and additives that are carefully designed to meet the stringent customer demands and internal specification requirements. They meet international standards and OEM approvals in many electronics markets. The selection of polymers, flame-retardants, anti-oxidants, UV-stabilisers and other additives is of great importance for products to meet requirements of properties such as tensile strength, elongation at break, flame retardancy, continuous operating tem- perature, heat shock, heat ageing, flexibility, chemical and solvent resistance and shrink temperature. TE Connectivity's Raychem hot melt adhesives are specifically formulated to be compat- ible with individual heat-shrink tubing compounds. These adhesives include a balance of polymers and additives that allow the adhesive to melt, flow, seal and adhere to a range of substrates at the shrink temperature of the overall tubing. • Cross-linking Radiation cross-linking enhances the polymer properties and provides heat-shrinkability or shape memory. Polymeric tubing is extruded and in a separate process the chemical structure is mod- ified to provide improved properties such as reduced deformation under load (creep), improved chemical and solvent resistance, increased abrasion resistance, improved impact properties and shape memory charac- teristics. Due to the three dimensional cross-links which are formed during the cross-linking process, the tubing does not melt and obtains its perfect shape memory. • Manufacturing technology Based on many years of experience Raychem tubing by TE Connectivity is produced using optimised manufacturing pro- cesses by the following steps: compounding, extrusion, radiation cross-linking and expansion. Compounding processes are used to mix selected polymers and additives. The resulting compounds are then extruded using opti- mised screw and die designs to produce homogeneous and con- sistent tubing. The tubing is then cross-linked using electron beam radiation. In the expansion process the diameter of the tubing is increased by forces at high temperature. Immediately after the tubing reaches its required expanded size, it is cooled down and retains its expanded dimensions. Unmodified Polymer Cross-linked Polymer