Three types of polypropylene are currently available.
Homopolymers – A General Purpose Grade that can be used in a variety of different applications.
Block copolymers – incorporating 5-15% ethylene, have much improved impact resistance extending to temperatures below -20oC.
Random copolymers – incorporate co-monomer units arranged randomly along the polypropylene long chain molecule. Such polymers typically containing 1-7% ethylene are selected where a lower melting point, more flexibility and enhanced clarity are advantageous.
Different PP grades are available dependent on the application and chosen processing method.
Reusable and collapsible/stackable crates are a great application for PP, providing ease to transport (both full and empty) and allow simple, safe and efficient storage of products and are ideal for Just-in-Time (JIT) storage solutions. As a consequence, supermarkets are beginning to revert to use and similar products are finding application in the automotive supply chain.
Caps and Closures manufactured of PP have benefited from growth in the PET bottle market, particularly for mineral water containment and that of edible oil.
PP is blow moulded to produce bottles for the packaging of a range of products including condiments, detergent and toiletries markets, PP thin-walled containers (e.g. yoghurt pots) are also common. PP competes with PS in this field, offering a cheaper material option (processing costs can, however, offset this benefit). PP is semi-crystalline product and consequently has a narrower processing window than PS and tends to display higher shrinkage. Modern thermoforming machinery is capable (with two sets of tools) of processing either PP or PS, consequently the future infiltration of PP is very much dependent on price fluctuations.
In the automotive sector PP is utilised as a monomaterial solution for automotive interiors. The monomaterial dashboard is becoming increasingly achievable, PP film cushioning, film skins, and powder slush moulding and even blow moulded parts with integral PP textile covers are emerging. Bumpers, cladding, and exterior trim are also available manufactured from polypropylene. Polypropylene developed for such applications provides low coefficient of linear thermal expansion and specific gravity, high chemical resistance and good weatherability, processability and impact/stiffness balance. Improvements with colour-at-the-press and pre-coloured PP have also reduced or eliminated the need for painting in some applications.
Products classified in this sector are Housewares, Furniture, Appliances, Luggage, Toys, Battery Cases and other “durable” items for home, garden or leisure use. Injection Moulding dominates the the conversion process used for these products.
PP Fibre is utilised in a host of applications including tape, strapping, bulk continuous filament, staple fibres.
Please contact us to review requirements and obtain specifications