Polyvinyl chloride (PVC)
Very widely spread class of plastics, one of the oldest plastic materials used since around 1930
- Simple and inexpensive production
- Protection of fossil raw materials since half of it is made from sodium chloride.
- Highly resistant to various chemicals, environmental influences and in particular UV radiation
- Flame retardant
By admixtures, the properties of the PVC can be modified in a number of ways. In its pure form, PVC is very hard and brittle. Accordingly, it is almost always modified to make it impact-resistant at least. By adding plasticisers, rubber-like properties are achieved. The benefit is the much higher speed and lower costs of thermoplastic processing compared to the elastomer vulcanisation of rubber. Accordingly, inexpensive “rubber” items are often made of soft PVC. However, PVC has some major setbacks: Large volumes of environmentally harmful chlorine compounds are generated during production and disposal of PVC. In today’s production of the material, this is unproblematic due to appropriate protective measures, but the often uncontrolled disposal leads to environmental problems. Especially during incineration (outside of incineration plants with appropriate filter equipment), aggressive chlorine gas is initially released, which reacts to likewise aggressive hydrochloric acid and harmful chlorinated hydrocarbons. Also the additives to be found in all PVCs and the plasticisers in soft PVS harm the environment. Above all, these plasticisers are easily dissolved out of the material and migrate and evaporate spontaneously over time. Although PVC can be modified to increase its impact strength, it tends to become brittle in the cold. The properties of soft PVC compare to those of rubber only at superficial consideration. PVC is much less resistant to tearing and abrasion and becomes much harder at low temperatures. It is by far inferior in terms of resilience and elongation at break. As PVC ages, it loses its rubber-elastic properties due to bleeding of the plasticisers. By means of plasma activation, the bonding properties of PVC for bonding and printing can be improved. However, bled-out plasticisers at the surface are problematic. After a certain period of use, an initially perfect bond will deteriorate due to bleeding of the plasticisers.
