Polyamides, in general, are polymers highly resistant to impact, temperature, UV, ageing and chemical cracking stress. For this reason, their field of application is very wide.
The use of polyamides covers many industrial sectors: construction, healthcare, cables and jacketing, automotive and aeronautics.
If we focus on the automotive industry, polyamides are decisive in the production of technical parts and supports, steering columns, shock absorber stops, most steering wheel indicator controls, headrest supports and consoles, fastenings, under bonnet parts and all kinds of pipes for turbo and hydraulic circuits, water pumps and filter covers.
They can be processed by injection, extrusion and blow moulding and even IBM and EBM. Processing temperatures range from 240°C to 340°C, which also coincides with the variations in thermal resistance of the different polyamide families.
The most common polyamides
There are several types of polyamides on the market, but the most common are polyamide 6, polyamide 66 and polyamide 666. Many of our polyamide grades have all kinds of approvals for automotive, food and even medical and pharmaceutical uses.
It is the most common type of polyamide, it has good properties making it very suitable for all types of applications, especially at automotive level, the main chemical base being caprolactam. It is normally presented both in natural and black and with glass fibre fillers, mineral fillers, impact modified, fireproofed and self-lubricated. It is widely used for technical parts in general due to its good cost-performance ratio. Auto, electro and general applications, medium dimensional stability and impact.
In contrast to Polyamide 6, this variant gains a lot in elasticity and toughness, therefore naturally also in impact. These materials are chemically based on Adipic Acid. Their main applications are industrial applications where the mechanical requirements must be higher, as is the case of railways, for example, the angled plates for fastening our railways. Good dimensional stability and impact. Good thermal resistance. Higher cost than Polyamide 6.
Triple 6 is a polyamide combining characteristics of PA6 + PA66, therefore, a good compromise between the best characteristics of the two, good impact, and good cost-performance ratio.
Polyamides for metal replacement
Replacement of metals by polyamides has very significant advantages: a considerable reduction in weight, enormous cost savings and a much shorter production time, since it does not require post-processing as in the case of metal parts, where the excess metal parts have to be removed during post-injection.
At Quimidroga, we have two types of polyamides for metal replacement.
Special polyamides also known as polyphthalamides. Main bases are isophthalic and terephthalic acid. Their main application is metal replacement, basically Aluminium and Zamac.
Unlike Polyamides 6, 66 and triple 6, Polyphthalamides are low moisture absorbing materials. This characteristic makes them highly stable against moisture changes and even hydrolysis. Polyamides in general are hygroscopic materials, i.e., they absorb moisture, so there are generally large differences between before and after this absorption, what affects them enormously in terms of impact and dimensional stability. Polyphthalamides, having this low absorption capacity, are highly dimensionally stable and meet high requirements in terms of impact and strength, a combination that is very difficult to achieve in standard grades.
If we look deeper into our range, there are two well differentiated types:
GV range, basic for metal replacement without the need for high resistance to temperature. Elastic moduli ranging from 12.000 Mpa up to 30.000 Mpa.
HT range, in the same way, for metal replacement but this time, material with high thermal requirements, with constant working temperatures of 150ºC and peaks of 220ºC. Very good resistance to hydrolysis and under high fatigue conditions. Grades developed especially for the sanitary sector, water meters, electrical sector parts, etc.
It is the range of polyamides for metal replacement with the lowest moisture absorption capacity, therefore very dimensionally stable. Also, with very high chemical and impact resistance. Chemical base is laurylactam. Its main use is in the automotive industry, basic for the production of fluid conductions such as petrol and diesel fuels, as well as DOT4 brake fluid.
We also have a range of polyamides 12 “Green”, with plant-based content and therefore much more environmentally friendly.