PVC (polyvinylchloride) is a universal, proven, and reliable material. It was developed in the thirties of the 20th century as one of the first synthetic materials – plastics. It is a material well workable using various technologies, e.g. rolling, extrusion, depositing, or casting, therefore it is predestined for wide range of applications.
PVC has a unique combination of features, which can be further modified in various ways using processing additives. PVC is usually classified into softened – called most frequently PVC-P, ands hard – called PVC-U. Polyvinylchloride ranks among materials that can be recycled well and reused in the manufacture of products. Recyclable PVC is marked PVC-R. In general, products from PVC are called vinyl products.
PVC-P is suitable especially for applications where flexibility and elasticity are essential. Main fields of softened PVC’s application include:
– subjects of common use – raincoats, inflatable toys, table cloths, janitorial gloves
– building industry – insulation foils, e.g. swimming pool insulation, ground and roof insulation, green roofs, flooring of various types in rolls and tiles, soft profiles and baseboards, wallpapers
– automotive and electrical industry – most commonly cable sheathing
– health care – blood pocket bags, medical tubes and hoses
– other industries – promotional items, billboards, packages.
PVC-P features are modified with respect to particular application. Where the appearance is important, the frequent requirement is to achieve the specific colour shade, multi-colour print, or to create a design on the product surface (wood or leather imitation). In technical applications, the most frequent requirements are the long service life and durability. Using the right additives, the service life may reach 10, 15 years, or even more.
PVC-U features higher strength, consistence, and hardness. It is used most frequently in products for technical applications where its physical-mechanical features together with long service life are appreciated. Typical examples of applications include:
– transport pipes for various liquids (drinking water, waste)
– profiles – mainly window profiles, but also smaller technical profiles for automotive or electrical industry
– moulded products – fittings, transient and end components of conducts
– drug and medicament packages, so-called blister packages
– food product packages, e.g. frozen products.
PVC itself is a powdery material. By adding various processing additives according to requirements of the final application, a mixture is prepared in the pellet form – PVC-U granulate. The granulate is processed further into a final product using thermal and pressure effects. For the abovementioned technical applications, extrusion technology (pipes, profiles), injection moulding (3D products) or moulding processes are used.
PP (polypropylene) is the second most frequently used material in Europe. Its share in consumption of plastic materials ranges about 20 %. Polypropylene is By its features and use, polypropylene is similar to polyethylene, therefore both of these polymers are classified in the same group indicated as polyolefins. Unlike PE, PP however features higher strength and consistency, and since its melting temperature is higher, it shows good temperature stability. PP consistency imparts good dimensional stability to products.
Polypropylene can be found almost anywhere: in packaging materials, household appliances, clothing, means of transport, and many other products. More than half of the world PP production is used for packages. It is also used in technical applications.
It is used among others in the production of:
– packages – flexible foils, pots for dairy products and beverage machines, moulded trays, package caps, bottle caps, bags, notebook covers
– textile – fibres (thermal underwear, carpets), strings, ropes, binding strips
– pipes – tubes of various diameters for water and other liquids
– automotive parts – bumpers, tanks, cable sheathing
consumer goods – ball-point pens, measuring jugs, trays, small items including promotional
– PP is used also in the production of plastic currency.
TPE, or thermoplastic elastomers, are materials with features (strength, ductility) similar to rubbers, while they can be processed using plastic-processing technologies (rolling, extrusion, injection, press moulding). These remarkable features are caused by interconnecting (co-polymerization) two different parts – the solid and hard part (melting of which enables processing of the material) and the elastic part (which causes strength of the material and its softness on touch).
The advantage of TPE is a wide temperature range of its use, which distinguishes it from regular plastics. These materials have also good resistance against mechanical stress. The new generation of TPE materials is based on polyolefins. These materials represent an alternative to softened PVC in applications such as water-proofing foils, profiles, or hoses.
TPE’s application field includes:
– consumer industry – soft and flexible parts of tools such as toothbrushes, shavers, ball pens
– electro-technical industry – sheathing of electric cables, soft headphones
– building industry – insulation foils
– sports – snowmobile belt pulleys, in-line skates, ski accessories
– health care – catheters, tubing
– rubber substitutes – sealing rings, sealing liners, shoe soles, bicycle air tubes
PE (polyethylene) is the most frequently used plastic in the world. Its annual production exceeds 90 million tons. It was developed in 1933. This invention was essential for the development of modern plastic materials, which we cannot imagine our life without anymore. From the chemical point of view, the polyethylene structure is very simple, therefore it can be produced relatively in an easy and inexpensive way. According to its density, polyethylene is classified into two major types, so-called low-density (LDPE) and high-density (HDPE), the third type is the so-called linear low-density PE (LLDPE).
Both PE types can be processed easily using plastic-processing technologies, and manufacture products of various shapes and sizes from them. In general, polyethylene has an excellent strength, high toughness, and ductility; products may be transparent or coloured with pigments. The common PE processing method is extrusion (2D products) and injection moulding (3D products).
The best-known polyethylene applications include:
– flexible packages – bags for fresh and frozen food – products, shopping bags, extensible foils,
– solid packages – bottles for detergents and cosmetics, cans, barrels, large-size containers
– daily need products – minor kitchen dishes
– tubes and pipes
Polyethylene may be recycled. It is widely present in the communal waste, therefore there are efforts to sort it (yellow container for sorted waste) and reuse.
LDPE is a polyethylene with lower density. It is the most frequently used material in the production of foils, in particular for packaging. All simple types of disposable bags, garbage bags, and shopping bags are made just from LDPE. The reason is particularly its low price and easy processing ability.
Foils are manufactured by extrusion, either as 2D foils or hoses (tubular extrusion). Foils can be made as very thin (bags for baked goods) or thick-walled (large bags). Package thickness may be adapted to application requirements from 30 micrometers (0.030 mm) up to 200 micrometers.
Should the final package be resistant against perforation, PE foils may be laminated with another foil type improving features of the final package. For example, lamination with PET foil (polyethylene-terephthalate) is used in the production of foodstuff bags for pets. Lamination with a paperboard is applied in the production of juice packages (Tetrapack type).
The benefit of LDPE is that it can be imprinted very well. Shopping bags and large bags can be decorated with multi-colour print. This material can also be welded to achieve various shapes of pouches and bags. Recycled PE may be returned back for the production of pouches and bags, which saves the environment.
HDPE, or high-density polyethylene, is under ordinary circumstances a material of milky colour that differs from other polyethylene types by higher strength and ductility. Since the material is more consistent, the foils and packages produced from it are stronger. The HDPE bag thus has a higher load capacity than a LDPE bag of identical thickness. This is beneficial in the production of very thin bags; HDPE bag thickness is from 7 micrometers.
In addition to flexible packages, HDPE is also a very suitable material for strong packages. Best-known allocations are cosmetic bottles (detergents, shampoos), and cans.
HDPE is used also in technical applications, e.g. as septic tanks, in the production of pipes, and for sheathing of cables and harnesses. Septic tanks may have very complicated shapes and large capacities. The advantage of HDPE in these applications is its natural strength and consistency.
ABS is an abbreviation of acrylonitrile-butadiene-styrene, which is a so-called terpolymer created by combination of styrene and acrylonitrile in the presence of butadiene. The resulting material combines features of initial compounds, i.e. hardness of styrene and ductility of butadiene. The share of individual compounds may be changed, which modifies features of resulting ABS.
The most ABS interesting features are strength and ductility, particularly the impact strength. It is strong and resistant even in low temperatures, easily workable using the extraction technology, and has an excellent surface quality – can be painted easily and it is pleasant on touch. Its features are stable in temperatures from -20 °C to do 80 °C. This enables a wide application range, especially as a technical and structural material.
ABS is used in the production of:
– exterior and interior automotive parts – dashboards, various covers
– household appliances (casings of vacuum cleaners, shells of kitchen appliances)
– telecommunication and electro-acoustic devices (phones)
– sports goods
– musical instruments
– medical technology
– toys, e.g. Lego building kits are made from ABS.