Why Nylon Printed Fabric Has Poor Fastness and How to Improve It

Poor print fastness often appears in nylon fabric printing. The problem becomes more obvious when factories print on waterproof or water-repellent nylon fabrics with pigment printing systems.

This issue does not come from one single factor. Fabric type, fiber surface, water-repellent finishing, printing paste, crosslinking agent, curing temperature, and printing operation all affect the final result. Therefore, before printing, manufacturers need to check the fabric surface carefully and choose a suitable printing system.

1. Nylon Fiber Properties and Print Fastness

Nylon and polyester are synthetic fibers. Compared with natural fibers, they have a compact molecular structure, low moisture absorption, and a very smooth fiber surface.

Because of this, pigment printing paste cannot easily enter the fiber. It mainly stays on the fabric surface and relies on adhesive resin to hold the printed layer.

Therefore, print fastness depends mainly on two points: how well the resin bonds to the fiber surface, and how strong the resin film remains after drying and curing.

As a result, nylon and polyester fabrics usually show lower print fastness than natural fiber fabrics.

2. Waterproof vs Water-Repellent Finishing

Many people use “waterproof” and “water-repellent” as the same idea. However, in dyeing and finishing, they mean different things.

Water-repellent fabric does not wet easily. Water forms droplets on the surface and rolls away, much like water on a lotus leaf.

Waterproof fabric blocks water penetration. For example, coated nylon rainwear can stop rain from passing through the fabric.

In many cases, factories print waterproof nylon fabric on the uncoated side. Therefore, the waterproof coating itself may not greatly affect print fastness. Instead, the water-repellent finish creates the bigger problem.

Water-repellent agents reduce surface adhesion. The stronger the repellency, the harder it becomes for printing paste to bond with the fiber surface.

For this reason, factories should check the fabric before printing. Some nylon fabrics have only waterproof coating. Some have only water-repellent finishing. Some have both, while others have neither. Once the surface condition becomes clear, the printing paste and process can match the fabric more accurately.

3. Choose the Right Printing Paste or Ink

Printing systems for nylon and polyester mainly include water-based printing emulsions and solvent-based printing inks.

From the resin side, common choices include polyacrylate and polyurethane. Both resins can work in water-based or solvent-based systems.

In general, solvent-based inks offer better fastness than water-based emulsions. Polyurethane usually performs better than polyacrylate. Also, two-component systems usually provide better durability than one-component systems.

Therefore, two-component solvent-based polyurethane ink often gives the strongest print fastness.

However, production cannot only focus on fastness. Factories also need to consider worker safety, environmental requirements, cost, and actual operation. The best choice should balance performance and practicality.

4. Use Crosslinking Agents Properly

Crosslinking agents help improve print fastness. They react with the resin and form a stronger network structure.

This structure improves adhesion to the fabric surface and strengthens the printing film. As a result, the printed layer can better resist rubbing, washing, and peeling.

One-component printing paste can work alone, or it can work with a crosslinking agent. Two-component printing paste needs a crosslinking agent to achieve its intended performance.

However, too much crosslinking agent may cause problems. It can make the fabric feel harder, and it may not continue to improve fastness. When using oil-based crosslinking agents, factories should use the prepared ink quickly. If the ink sits too long, it may thicken, gel, or lose effectiveness.

5. Control the Printing and Curing Process

Nylon fabric printing often involves small batches, many designs, and many special requirements. Because of this, process control matters a lot.

Factories usually test nylon print fastness through dry rubbing, wet rubbing, washing, or adhesive tape testing. These methods help check whether the resin film cracks, peels, or comes off.

After printing, drying and curing strongly affect fastness. Natural drying and low-temperature hot air drying can work for some products. However, high-temperature baking or heat pressing after drying often gives better fastness.

Heat helps remove water or solvent more completely. It also helps the resin and crosslinking agent react more fully. As a result, the printing film bonds more tightly with the fabric surface.

Even so, factories must control temperature and time carefully. Excessive heat can cause white fabrics to yellow. It can also cause color migration on dyed fabrics. In serious cases, high heat may damage the resin film, reduce fastness, shrink the fabric, or even scorch the material.

Therefore, factories should run sample tests before bulk production. Testing helps confirm the right paste, curing temperature, curing time, and final process conditions.

Printing operation also affects fastness. The printing table, screen mesh, squeegee shape, squeegee hardness, and printing pressure all influence the printed surface.

Most importantly, the paste amount should stay within a suitable range. Too much paste can create an overly thick resin film on the fabric surface. A thick film may look solid at first, but it often performs worse during rubbing and washing.

Conclusion

Nylon printed fabric fastness depends on fiber properties, surface finishing, printing paste, crosslinking agent, curing process, and printing operation.

Among these factors, water-repellent finishing often creates the biggest challenge because it weakens adhesion between the printing film and the fabric surface.

To improve fastness, manufacturers should first identify the fabric surface condition. Then, they should choose a suitable printing system, use crosslinking agents properly, control curing conditions, and adjust the printing operation.

With the right process, nylon printed fabric can achieve better rubbing fastness, washing fastness, and overall production stability.