What are Engineering Plastics? an in depth technical guide
metals4U stock PA6 and Acetal copolymer in extruded rod, tube, and sheet presentations.
Nylon 6 and Acetal are both engineering plastics that are categorised as 'thermoplastics'; these types of plastic materials are easily moulded and pliable when heated to a specified maximum temperature and solidify and harden when cool. Engineering plastics can offer some useful advantages over the use of metal in many applications. Plastics will not rust, they have excellent thermal and electrical insulation properties, and are very economical to purchase and use.
Nylon 6 and Acetal are lightweight materials that are easy to machine, mould, and fabricate, with the added advantage of strength and good resistance to creep.
Engineering plastics are suitable for the manufacture of plain bearings, bushes, gears, cams, rollers, seal rings, slide bearings, insulators, relay and transformer housing, pump components, valve bodies, and general applications in engineering, automotive, and catering sectors.
How engineering plastics are made
Nylon, also referred to as PA6, or Polycaprolactum, is produced from a monomer called Caprolactum; this is an organic compound which is a cyclic amide (a lactum) of caproic acid. Nylon 6 is the product of the polymerisation process of aminocaproic acid to produce a polymer. (A polymer is repeated chain of subunits joined by amide links) These nylon polymers are then heat processed to produce extruded or moulded profiles for use.
Acetal, POM C, or Polyoxymethylene Copolymer as it is also known, is produced by converting formaldehyde into trioxane by sulphuric acid, or acidic ion exchange resins, via acid catalysis. The trioxane is then purified by extraction or distillation to remove water and other impurities that contain hydrogen. Acetal is then processed by heat and pressure to be formed into injection, blow, and rotational moulded profiles or extrusions.
Excellent for machining, lightweight, and low friction qualities make engineering plastics a viable alternative to metal. Engineering plastics can be machined without the need for lubricant and coolants for most processes; this makes work handling and cleaning up easier.
Nylon is hygroscopic, which means that it is moisture sensitive. This factor needs to be considered when choosing the correct engineering plastic for your project.
Acetal is not hygroscopic; therefore, it can be used in applications where the absorption of liquid is not required or desired.
When thermoplastics become cold they are prone to becoming brittle. It is not recommended to store plastics in very cold environments or attempt to work with them in a chilled state.
Engineering plastics are not magnetic.
Nylon 6 and Acetal have very good corrosion resistant properties to a wide range of chemicals.
Acetal has good resistance to most common solvents, esters, lubricants, aqueous alkali and acidic solutions between ph.5 through to ph.11, and ketones, however, it has low resistance to phenols, concentrated mineral alkalis and acids, and halogens.
Nylon 6 is highly resistant to fats, oils, ethers, esters, ketones, and hydrocarbons, but is not resistant to mineral acids and some organic acids, oxidising agents, and halogens.
Thermoplastics can be heated to their melting point, cooled and reheated again without suffering degradation of their properties; this is particularly useful in terms of recyclability of Nylon 6 and acetal.
Nylon and Acetal can both be recycled by chemical and mechanical recycling processes without compromising their physicochemical integrity.
The waste thermoplastic is cleaned and processed (by shredding) into pellets to be reused.
The plastics are chemically de-polymerised and broken down into their monomer components. The plastic is then re-polymerised and re-manufactured into stock profiles for re-use.
Acetal and PA6 nylon are not biodegradable.
As there are many similarities and differences between Acetal and Nylon 6, it is important to select the type of plastic best suited to your chosen application. It is important to consider exposure to chemicals, behaviour with moisture and temperature, expansion and creep, and machinability.Back to top