Thermoplastic Coatings & Composites

  In general, composite materials such as fiberglass and carbon fiber are popular with manufacturers because of their light weight and mechanical properties that are superior to traditional materials such as steel and aluminum. Composites can also be designed with special coatings integrated into products to improve their functionality.

  Glass fiber chopped strands for thermoplastics are formulated with silane-based coupling agents and special sizing agents. Good compatibility, excellent clustering and fluidity, good forming and processing performance, can endow composite materials with excellent mechanical properties and surface state.


  Patrick Loock, Business Leader, Products and Applications, at composite tubing manufacturer Exel Composites, discusses how composites made with thermoplastic functional coatings can better control properties such as friction, adhesion and finish. There are two main types of resins used in the production of composites: thermosetting resins and thermoplastic resins. Thermoset resins, the most common of the two types, harden by curing to form highly cross-linked polymers with insoluble or insoluble rigid bonds that do not melt when exposed to heat. Although uncommon in pultrusion, thermoplastic resins are being increasingly exploited. A thermoplastic is a polymer materials that softens when heated and solidifies when cooled. It's a reversible process, with no chemical bonds being made and broken, which means you can remelt and shape them as needed and shape them into any shape. Thermoplastics that can be used in composites include thermoplastic polyurethane (TPU), polymethyl methacrylate (PMMA), polyethylene (PE), polyamide (PA) and polypropylene (PP), among others.

  Combining thermoplastic functional coatings with thermoset composites. By extruding thermoplastic functional coatings as a production step in composites, additional mechanical properties such as shock absorption, bond strength between components, friction and corrosion resistance can be imparted to the material and more can be added to the shape design aesthetic possibilities. Thermoplastic coatings can provide composites with a wider range of finishing possibilities, so more products can be derived, such as composite materials with gloss, matte, rubber or even metal appearance, and can be seamlessly integrated with existing structures.

  Metal-look finishes are popular because composites are often used as replacements for metal components in existing structures, allowing them to blend more visually. Thermoplastic coatings can also provide additional functional properties to composites. For example, when thermoplastic coatings are used on telescoping components, increased friction between the tube and lock can subject the device to greater external forces.Prepreg carbon cloth has very good mechanical properties, providing the strength and weight required for composite materials, but sometimes it does not have the friction and adhesion properties required for the application, by coating carbon fiber composite materials with thermoplastic coatings, the product can obtain the required Friction and adhesion properties, as well as additional protection of the composite from environmental elements such as weather, water or other environmental damage to the surface of the material. This has potential applications in examples such as marine applications, formation control or tension members.
  Exel Composites has extensive expertise in continuous composite manufacturing processes such as pultrusion and stretch winding, and provides in-line functional coating of composites during the manufacturing process, rather than adding coating after production. The process takes advantage of all the advantages of thermoplastic-coated composites, such as shock absorption and corrosion resistance, while reducing manufacturing complexity. In addition, the pultrusion and drawing winding process ensures the production quality of the product with a high degree of repeatability due to precise fiber alignment and process control.