The thermosetting resins include phenolic resin and melamine resin, which are thermally hardened and never become soft again. Thermoplastic resins include PVC, polyethylene (PE), polystyrene (PS) and polypropylene (PP), which can be re-softened by heating.
Usually, thermoplastics are supplied in the form of pelletised material (compounds) with additives (antioxidants, etc.) already blended in it. However, PVC resin is often supplied in powder form and long term storage is possible since the material is resistant to oxidation and degradation. Various additives and pigments are added to PVC during the processing stage, and the blend is then converted into PVC products.
PVC is sometimes known as ‘Vinyl’ in Europe and predominantly so in North America. In Europe, ‘Vinyl’ usually refers to certain specific flexible applications, such as flooring, decorative sheets and artificial leather.
PVC is a thermoplastic made of 57% chlorine (derived from industrial grade salt) and 43% carbon (derived predominantly from oil / gas via ethylene). It is less dependent than other polymers on crude oil or natural gas, which are nonrenewable, and hence can be regarded as a natural resource saving plastic, in contrast to plastics such as PE, PP, PET and PS, which are totally dependent on oil or gas. This chlorine gives to PVC excellent fire resistance.
What is PVC used for?
The diversity of PVC applications challenges the imagination. In everyday life, they are all around us. PVC is used for everything from construction profiles to medical devices, from roofing membranes to credit cards, and from children’s toys to pipes for water and gas. Few other materials are as versatile or able to fulfil such demanding specifications. In this way, PVC fosters creativity and innovation, making new possibilities available every day.
Why use PVC?
Simply because PVC products make life safer, bring comfort and joy, and help conserve natural resources and combat climate change. And due to an excellent cost-performance ratio, PVC allows people of all income levels access to these crucial benefits.
There are many reasons why PVC and safety are inseparable. Due to unsurpassed technical properties, PVC is the most used material for life-saving, disposable, medical devices. For instance, medical tubing of PVC does not kink or break and is easy to sterilise. Because of inherent fire resistance, wire and cables sheathed with PVC prevent potentially fatal electrical accidents.
Further, PVC is a strong material. When used for car components, PVC thus helps to reduce the risk of injuries in case of accidents.
How does PVC help to conserve natural resources and combat climate change?
Because PVC is intrinsically a low-carbon material which consumes less primary energy than many other materials and is easy to recycle.
Also, most PVC products are very long lasting and require a minimum of maintenance and repair. For instance, the service life of PVC water and sewage piping is more than 100 years. And modern cars last many years longer simply because PVC protects the underside from water and corrosion.