Textile coatings are an essential element of creating high-performance industrial components. Coatings can be aqueous, solvent, or 100% solid. Depending on the required attributes, there are several coating methods available:
- Direct coating
- Immersion coating
- Direct roll coating
- Transfer coating
- Heat lamination
- Adhesive lamination
Specially designed types of coatings are an important value-adding technique, enhancing textile functionality and extending performance.
Direct coating uses a blade or fixed knife to spread a liquid polymer coating onto a textile. The height of the blade above the fabric determines the coating’s thickness. After application, the fabric is completely or partially oven-cured.
This method is ideal for tightly woven or dense, non-woven materials where the coating will not easily flow through the fabric.
There are direct coating techniques to choose from, including:
- Knife over air. The knife is fixed overtop the substrate.
- Knife over roller. The blade suspends over a roller without direct substrate contact.
Common applications include airbag, gasket, inflatable, impermeable, parachute, and power transmission belt fabrics.
Also called dip coating, immersion coating is immersing a fabric into a liquid polymer bath. Next, the fabric runs through rollers, squeezing out excess polymer before curing or partial curing.
This technique applies coatings to both fabric sides in one pass. It can apply resins, water repellents, rubber coatings, silicone, and adhesive chemistry, such as RFN and RFL.
Immersion coating is often used in fabrics for power transmission belts, tires, and aerospace heat shields. It can improve durability by applying antistatic and water-resistant coatings.
Direct Roll Coating (Reverse Roll and Gravure Coating)
Gravure coating uses an engraved roller with embossed lines or dots. Those fill with coating, which transfers to the substrate when fabric slides between the engraved and pressure rollers.
Reverse roll coating is a three- or four-roll system. The backup roller picks up the polymer, measuring using the gap between the application and metering rollers. The application roller transfers coating onto fabric.
Direct roll coating is suited for liquids featuring high viscosity, like rubber. It coats only one side of the fabric, but double-passing covers both sides. This system is ideal for fabrics featuring high stretch, like knits.
This process makes gasket materials and outer wrappings or backings for transmission belts.
In this technique, resin coating spreads onto transfer paper, forming a film that is then laminated onto a textile. This method is suitable for open fabrics, which keep coatings from flowing through.
Transfer coating can produce thermal protection systems and synthetic leathers.
With thermoplastic polymers like PVC, polyurethane, and polyolefins, heat lamination uses extruded or blown films married to a fabric with heated rollers. The films form a composite system by softening and pressing together. An adhesion system may also be used.
This technique creates weldable and air-holding fabrics, among others. It works on a variety of fabrics such as open scrims, knits, nonwovens and heavy woven materials. Lamination allows polymer films to be applied to either one or both sides of a fabric in a single pass. Composite systems featuring multiple fabric types and films can also join together.
Heat lamination has uses in many industries:
- Aerospace/defense. This industry uses the process for anti-g suit bladders, aluminized films for radiant heat protection, dry bags, drysuits, escape slides, rafts, life vests, and more.
- Medical. Blood pressure cuffs, inflatable tourniquets, inflatable beds, and pressure infuser bags are some medical applications.
- Recreation. The recreation industry uses this technique in SCUBA buoyancy compensators, sports pads, and life vests.
Adhesive lamination uses an adhesive coating or web to bond fabric to a blown or extruded film.
It is commonly used in medical and automotive applications, such as to create blood pressure cuffs or to bond foam or non-woven materials to films.
Expert Textile Coating From Tex Tech Industries, Inc.
Coating and lamination technology provides a powerful tool for advancing textile performance. At Tex Tech, we design proper coating chemistry and execute application methods to meet the most demanding requirements. To learn more about our coating technology and how it can meet your needs, contact us or request a quote today.