Material Knowledge Plastics
Cost-effective, resilient and corrosion-resistant alternatives
Plastics are synthetically produced, organic materials. They are produced from the raw materials crude oil or natural gas as well as other source materials, through chemical conversion. Plastics have become an increasingly important material in technology.
While in the past they were used as substitute materials, today they have replaced old materials in many areas of use. Their versatility is based on the special properties of plastics and the possibility of producing plastics with very different properties.
More Information About Plastics:
Low density: 0.9 to 2.2 kg/dm³
Electric and heat insulating
Corrosion-resistant against many chemicals and aggressive environmental influences
From hard and rigid to soft and elastic. Plastics are easy to form and machine and can be cast.
Overview
Definition of Plastics
Plastics are defined as solid materials whose basic components are synthetically or semi-synthetically produced polymers with organic molecular chains. An item made of plastic consists of millions of very long, intertwined molecular chains (polymers) composed of repeating basic units (monomers).
A special feature of plastics is that their technical properties, such as the ability to be formed, hardness, elasticity, breaking strength, temperature and heat resistance as well as chemical resistance, can be varied to a large extent through the selection of the raw materials used, manufacturing process and blending.
For the processor, the stability characteristics, especially when heated, are the key properties of the plastics. Therefore, according to DIN 7724, plastics are divided into the following three groups according to their stability characteristics: Thermoplastics, Thermosets and Elastomers. The rigidity is essentially determined by the intrinsic structure of the plastics.
Properties of Plastic
- Inexpensive
- corrosion resistant
- resistant to many chemicals
- low thermal conductivity
- conductive
- excellent electric isolating properties
- economic
- durable
- low maintenance
Compared to other materials, plastics have a wealth of advantages and disadvantages, which are pronounced to different degrees in the different types.
Inexpensive – When is Plastic an Alternative to Steel?
Plastic is particularly cheap to produce and procure and is therefore often the first choice. The material is also very versatile, which means that a wide variety of products can be made from it.
A plastic version can therefore be an alternative to a steel version, depending on the requirements. For instance, a clamping lever with a plastic handle offers similar mechanical conditions to a clamping lever made of steel. In addition, the plastic version offers a far greater choice of colours.
Elektrische Isolierwirkung- Warum ist Kunststoff elektrisch isoliert
- The electrical resistance “R” of plastic is in the range of 10¹⁰ to 10¹⁸ and is thus over 15 times greater than that of the metal with the highest resistance, constantan. Consequently, plastics such as PVC, PET and ABS are used as insulating materials for electrical cables.
- A serious disadvantage of plastic electrical insulators is that they can become statically charged through friction. Subsequently, an uncontrolled static discharge can occur, which can damage products or other components.
- ESD plastics (ESD = electrostatic discharge) offer a solution to this problem. ESD plastics are characterised by their reduced electrical resistance and are statically conductive.
You can find suitable products from the ESD range here.
Plastics Technical Classification
Classification | Overview | Product example |
|---|---|---|
| Thermoplastic | ||
| Thermoset | ||
Elastomer | ||
Application Areas for Plastics
Plastics are used in almost all areas of everyday life. For example, plastics are used in consumer goods such as packaging materials, floor coverings, clothing, pipes and in paints and adhesives. Plastics are also found in toys and electronic devices such as laptops, mobile phones or monitors.
However, a large proportion of plastics are used in the automotive industry. Increasing quantities of plastics are being used in automobiles because they are often cheaper to produce and easier to process.
Chemically Resistant Plastic
Chemical media are used in numerous machines, equipment and processes. Chemical-resistant plastics therefore play a very important role in the planning and development of equipment and machinery. However, not every plastic is suitable for contact with every chemical medium.
Detailed information on the chemical resistance of plastics can often be found in reference tables. However, the results usually only look at individual criteria. A combination of different influencing factors can usually only be tested individually in practice and for each application.
The specific influencing factors in the application must therefore always be taken into account when selecting suitable chemical-resistant materials.
For example, NBR is a type of rubber based on acrylonitrile and butadiene. This material has good mechanical properties and greater abrasion resistance than most other elastomers. Due to its excellent resistance to mineral oils, oil/water emulsions and many fuel types, NBR is the standard material for O-rings and dynamic seals.
Plastics in General Use
In everyday life, we use the term plastic to describe the material from which a wealth of different objects are made, such as packaging foils, plastic bags, toys or Tupperware containers. We encounter a variety of plastics every single day, e.g. in dispensing machines, at the paper kiosk or in electronics shops.
PF31 is made from a phenol/formaldehyde resin, which is often mixed with organic fillers such as fine sawdust or textile fibres. The key properties of PF31 are excellent ability for hot moulding, very good thermal insulation and very good electrical insulation. This thermoset is typically used in thermally insulating grip elements for machine parts and household appliances or as light switch and socket housings. A suitable product from the PF31 range is the mushroom knob.
Plastics in the Automotive Industry
One of the reasons why plastic parts are increasingly being used in the construction of modern cars is the dynamic development of the processing technology. Plastics used in cars are capable of acquiring new properties and are therefore ideal for the rapidly changing requirements of the automotive industry.
ABS is an amorphous thermoplastic made from three raw materials: acrylonitrile, butadiene and styrene. This plastic is particularly characterised by its excellent hot moulding properties, good impact strength and a hard, scratch-resistant surface.
In addition, ABS is excellent for welding and gluing and is also easy to process. It can be coated particularly well with metals, making it possible, for example, to give a chrome-plated surface to a plastic part. Over 50% of the material produced is used in the automotive industry and for the housings of electrical appliances. In the ABS range, the Thermoplastic Cylinder Cleaners are among the suitable products.