Plastics; product characteristics

Thermoplastics are widely used in internal transport technology. The thermoplastics used by NDW and their specific properties are listed below.

Chip-proof polyvinyl chloride (PVC)
Chip-proof hard PVC is characterized by extreme toughness and reasonably high stiffness. This makes it not only highly suitable for use in the building industry, but also for uses in internal transport components such as load roller tubes. Special additives ensure that the material retains its characteristics at low temperatures to. The maximum working temperature is around 65°C. When subjected to too high a compressing or stretching load, it will begin to "creep" after a while and will distort permanently. The material is resistant to many chemicals, but in particular not resistant to among other things esters, chlorinated and aromatic hydrocarbons, ketones and concentrated oxidizing acids.

Polypropylene copolymer (PPco)
Polypropylene is characterized by its low cost, exceptionally good chemical resistance, low density and good mechanical properties, as well as being environmentally sound. It is not surprisingly one of the most commonly used plastics. As well as being used in most other branches of industry, polypropylene is employed widely in the foodstuffs industry. The minimum and maximum continuous working temperatures for PPco are approx. -15°C and 80°C respectively.
Despite the excellent resistance to many chemicals and solvents, PPco only has a limited resistance to concentrated acids, toluene, trichloroethylene and hydrocarbons in general. As well as PPco, NDW also uses antistatic polypropylene (PPcond) and special rubber-modified polypropylene (PPK) for components.

Polyoxymethylene (POM)
Polyoxymethylene is characterized in particular by its great strength and high stiffness, elasticity and hardwearing properties. POM absorbs very little moisture, which means that it creeps and changes shape very little. Partly because of these properties, including the low coefficient of friction, the material is often used for sprocket heads, sprockets, slide bearings and castors. Its long-term resistance to temperatures is specified as a minimum temperature of -40°C and a maximum temperature of 90°C. Polyoxymethylene has an excellent resistance to many chemicals and can be used in the foodstuffs industry.

Polyamide 6 (PA 6)
Thanks to its excellent mechanical and tribological characteristics (also at higher temperatures, up to 110°C), polyamide 6 is the commonest plastic for technical uses. PA 6 does absorb relatively high amounts of moisture, leading to a very high impact resistance, but also to a reduction in the strength and stiffness and a greater tendency to lose shape. The chemical resistance is very good; nevertheless PA 6 is not resistant (or only has limited resistance) to acids, phenols, trichloroethylene and chlorinated hydrocarbons. PA 6 is reasonably resistant to UV light.

Polyamide 6.6 (PA 6.6)
Polyamide 6.6 is characterized by similar properties to those of PA 6. However, PA 6.6 absorbs less moisture, making it less chip-proof than PA 6 but stronger, stiffer and less likely to lose its shape. The maximum temperature that PA 6.6 can take for long periods is approx. 125°C. As well as PA 6.6, NDW uses a rubber-modified PA 6.6 (PA 6.6 HI) for certain components that need to be particularly impact resistant.

Polycarbonate (PC)
Polycarbonate is known in particular for its extreme impact resistance and high transparency, which have proved their worth in applications varying from CDs and light fittings through to riot shields. PC also resists both low and high temperatures well; the minimum and maximum working temperatures are -40°C and 125°C respectively. Moreover, PC does not scratch easily and has a high-gloss surface finish. The chemical resistance is limited, partly because of the susceptibility to brittleness in time due to environmental conditions such as contact with various chemicals.