Nylon 6 Vs. PTFE

Nylon, also known as Polyamide = PA

Key properties: abrasion resistance, low coefficient of friction, impact resistance, electrical insulation, corrosion and chemical resistance.

Nylon is a strong, tough engineering plastic with excellent abrasion, chemical and high-pressure resistance and is commonly used in the manufacture of electromechanical components.

For example, nylon cable ties and nylon retaining clips are the most common forms of products used to secure machine wires, air ducts, and more.

Commonly used are Nylon SHT, Nylon-White, Nylon-Black and so on.

Because it has a low coefficient of friction, it is also commonly used to replace metal bearings and bushings, thus eliminating the need for external lubrication, such as the use of nylon strips for the bottom lining of feed boxes.

Another example is the previously mentioned, wire rope cylinders used for gravity balancing, where the rope is coated with nylon for lubrication and sealing.

Extruded and cast and filled with a variety of other materials to improve impact resistance, coefficient of friction and stiffness, the downside of nylon is that it readily absorbs moisture.

Although there are many types of nylon, the most commonly used in sheets, rods and tubing are nylon 6 and nylon 66 (sometimes referred to as Pa6 and Pa66).

The numbers 6, 66, 11 and 12 indicate different molecular structures. Chemically, nylon 6 is a monomer with 6 carbon atoms. Nylon 66 is made from 2 monomers with 6 carbon atoms, hence the name 66.

Overall, Nylon 6 and Nylon 66 have very similar mechanical, thermal, and electrical properties, but each is unique in specific applications.

Nylon6 VS Nylon66

Nylon 6 = PA6 (casting)

Nylon 6 is usually made into sheets, rods and tubes by the liquid casting process, while for large diameter rods, tubes and thick plates, it is generally produced by casting, which is the most cost effective.

Nylon 6 is processed at lower temperatures and has low mold shrinkage.

It is inherently lightweight, has a bright appearance and is ideal for applications where toughness, impact resistance and surface finish are important.

Due to its very low viscosity, PA6 has excellent surface appearance and better processability than PA66.

Nylon 66 = PA66 (Extrusions)

Unlike the way Nylon 6 is processed, Nylon 66 is molded by thermoplastic extrusion.

Extrusion is a fast and economical method for making small diameter rods, tubes and sheets.

Unlike cast nylon 6 billet shapes, extruded nylon 66 sheets, rods and tubes can be manufactured to any length, which is an advantage for producing finished parts in a cost-effective manner.

Nylon 66 has a higher melting point and higher intermittent service temperature than cast nylon 6, making it suitable for high-temperature applications.

Nylon 66 also has improved stiffness, and higher tensile and flexural modulus, making it a good choice for applications where abrasion resistance and short-term heat resistance are important.

When PA6 reaches its limiting temperatures, or the hydrolytic stability of PA6 is no longer sufficient, PA66 can be used, which provides good surface appearance and weld strength, resulting in better burst resistance.

In addition nylon 66 is easy to dye and once dyed it shows excellent color fastness and is not susceptible to fading from sunlight and ozone or yellowing from nitrous oxide.

Nylon 6 is more popular in Europe, while Nylon 66 is very popular in the United States.

Nylon 46 (PA46)

It is a very superior material, much more water resistant than Nylon 66, and certainly more expensive.

Nylon46 Properties and Applications

Nylon46 Parameters

Nylon 46 is mainly used in applications requiring rigidity, creep resistance, continuous thermal stability, fatigue strength, and higher temperatures.

Examples include plant engineering, electrical industry, under the hood applications in automobiles, etc.

teflon = PTFE (Polytetrafluoroethylene), Teflon

Key Properties: Low coefficient of friction, high resistance to chemicals and solvents, excellent electrical properties, stable over a wide temperature range, non-toxic.

Teflon, also known as polytetrafluoroethylene (PTFE), is a soft, non-toxic fluoropolymer that belongs to the group of highly chemically resistant fluoro-thermoplastics.

Due to its high molecular weight, it cannot be processed by melting, but can only be made into semi-finished products by pressing and sintering.

The presence of fluorine provides enhanced chemical resistance, especially to strong acids, and produces a low coefficient of friction, low moisture absorption, and high electrical resistance.

Teflon has such a low coefficient of friction that very few materials adhere to it, and if they do, most can be peeled or wiped off, which is why many non-stick pans are coated with Teflon.

Teflon coating for non-stick cookware

There are several common types of Teflon coatings:

Teflon Coating(Dupont 958-303,Matt Black)

Teflon Coating(Dupont PTFE 851-214,Green)

Teflon Coating(Dupont ETFE 532-6118,BEIGE)

Teflon Coating(Dupont PFA 532-5310)

Teflon is very inactive, it is insoluble in most organic substances, so it is often used in reactive and corrosive chemical containers.

With its excellent PV (Pressure Velocity) value due to low friction, self-lubrication and long life, Teflon is also ideal for use in sliding parts such as plain bearings and gears. Industrial applications for Teflon also include seals, bearings, bushings, coil separators, terminals, and solid pipe and fittings.

In addition, Teflon is an excellent high-temperature insulator, and white Teflon terminals are often used where excellent insulation is required. Since Teflon's smooth surface is water resistant, the insulation is excellent even in high humidity. High quality IC sockets are made of Teflon to minimize current leakage.

Typical Applications of Teflon/PTFE

Although its mechanical properties are low compared to other engineering plastics, it is stable at both low and high temperatures (from -240°C to 260°C).

Moreover, the mechanical, electrical insulating and thermal properties of Teflon can be improved by the addition of fillers such as glass fibers, carbon, graphite, bronze and molybdenum disulfide (MoS2).

Therefore, Teflon is available in a variety of formulation types, including unfilled, glass-filled, bearing and FDA grades.

Raw (unfilled) Teflon: Unfilled Teflon is very soft and moldable and is typically used for chemically resistant seals and gaskets.

Glass-Filled Teflon: Glass-filled PTFE provides enhanced strength and stiffness, while the glass filler performs well in oxidizing environments and improves the wear characteristics of PTFE.

Carbon Filled: Reduces creep, increases stiffness and improves the thermal conductivity of PTFE. The wear resistance of carbon-filled compounds can be further improved when used in combination with graphite. These compounds are ideal for self-lubricating applications such as piston rings in compressor cylinders. In addition, graphite imparts excellent wear resistance to PTFE, and graphite-filled PTFE has an extremely low coefficient of friction.

Carbon Fiber Filled: Unlike glass fibers, carbon fibers are inert to hydrofluoric acid and strong bases. Carbon fiber PTFE compounds have a low coefficient of thermal expansion and high thermal conductivity. These parts are ideal for shock absorbers, water pumps and other automotive parts.

Bearing Specification Teflon: Bearing specifications have extremely low friction and high service temperatures. They are often specified for high-performance bearings and bushings, especially in chemical applications that require corrosion resistance.

Bronze-filled: Bronze-filled PTFE has high thermal and electrical conductivity, making it ideal for applications subjected to loads at extreme temperatures.

Comparison of PTFE, PEEK, PEK