General material information without obligation
Physical and Mechanical Properties
With 0,90-0,96 g/cm³ PE is a very light, partially crystalline thermoplastic material belonging to the class of polyolefins. VLD= Very Low Density ~0,90 g/cm³ and HD= High Density ~0,96 g/cm³ limit the range of density. PE in its normal condition is water repellent (hydrophobic) like the most Polyolefin’s. PE is very tough. The E-module, the tensile strength and the surface hardness have low values, growing up from VLD-PE to HD-PE. Good resistance to expansion cracks is principally given in the case of VLD-PE and LLD/MLD-PE. With increasing density, increasing melting index and increasing wall thickness PE becomes more sensitive to expansion cracks. If parts made of HD-PE (choice due to hardness and strength) are be exposed so wall thickness, melting index and density must bei optimal low.
Optical and Chemical Properties
In its natural colour PE is translucent. With reducing wall thickness of parts, PE moulded parts become increasingly transparent. Given correspondingly-designed injection moulding tools VLD/LLD-PE parts demonstrate a very shiny surface. Natural coloured PE parts are UV-sensitive and go yellow with time. - PE moulded parts have a non-polar surface and can therefore only be attacked by very few chemicals. PE is resistant to acids, lyes, alcohol, oil, and salt solutions. HD-PE is also resistant to benzin. VLD-PE and LD-PE swell in aliphatic and aromatic hydrocarbons. PE is not resistant to very strong oxidation media, e.g. nitric acid. The steam permeability level is small; gas permeability level is quite high in comparison to other plastics.
Resistance to Weather and Ageing
In the visible range PE is adequately resistant to radiation. UV rays produce oxidation of the PE parts surface and lead therefore to brittleness and to disintegration over time. A suitable colouration, e.g. soot, acts as a stabiliser, but reduces the resistance to ageing through heat. Addition of suitable UV stabilisers (HALS) prolongates outdoor usage of PE moulded parts in any colours up to some years.
Special Uses - Product Ranges
Fillers for more cheapening of material, various stabilisers, addition of PE-based thermoplastic elastomers (TPO) for softer and toughening setting - Transport containers, shims, pipe plugs, furniture fittings, one-way parts, substitution of soft PVC by VLD-PE for highly elastic parts.
The temperature range for permanent use of mechanical unloaded parts are, in the case of VLD-PE -50 to 80°C, in the case of LD-PE -50 to 95°C and in the case of HD-PE -50 to 105°C. PE lits at about 340°C. PE burns also outside the flame with a significant smell of wax weakly glowing and then drips down burning.
Physiological Behaviour and Joint
PE is physiological harmless as far as additives are used which are harmful to health. Some producers attest compatibility to foodstuff for their PE. Thanks to its good chemical consistency because of the non-polar parts surface only impact glues can be used. The surface of parts must be scuffed very accurately and based-coated first. Same effect has flaming and corona discharge. Better is to avoid gluing and varnishing PE moulded parts. PE can be jointed via heat element, friction-, vibration- or hot gas welding.