Photocatalytic Finishing

Definition and Overview

Photocatalytic finishing is a functional finishing process that uses the property of a photocatalyst activated by light to promote chemical reactions. It is not a term indicating the type of fiber itself or the weave or knit structure, but a type of finishing that adds functionality to the surface of fabric.

There are also visible-light-responsive finishes that work not only under sunlight but also under indoor lighting. However, the conditions under which the function appears, the substances targeted, and the degree of effect vary depending on the photocatalyst used, the finishing method, and the test conditions.

Features and Appearance

Depending on the action of the photocatalyst, it may be used for purposes such as decomposing adhered dirt and odor-causing substances, antibacterial performance, and UV protection. Since these functions are not always provided uniformly, it is important to check the required performance individually.

Finishing agents may use fine particles, and in properly finished fabric, some products minimize the effect on hand feel and hue. On the other hand, depending on the base fabric and finishing conditions, there may be differences in texture, whiteness, luster, and the color tone of dyed products.

Main Applications

In apparel, it is used for items that require a clean appearance and consideration for odor, such as shirts, blouses, uniforms, and workwear. In applications exposed to sunlight or lighting, it may be easier to take advantage of the characteristics of the finish.

It is also used for interior applications such as curtains. It is not a seasonal finish, but for spring and summer clothing where sweat, odor, and UV exposure are a concern, it may be planned in combination with other functional finishes.

Selection and Handling Notes

When selecting, check whether it is visible-light-responsive, the type of function expected, performance retention after washing, the target material, and the effect on color. If using it for labeling or promotion, confirm the test method, performance values, and usage conditions with the supplier, and make sure they match the actual specifications.

Shrinkage is not caused by the photocatalytic finish itself, but is mainly influenced by the base fabric fiber, structure, and post-finishing processing. Before mass production, perform soaking and washing tests to confirm shrinkage rate, color change, hand feel, and functional durability.

For sewing, set the needle, thread, and thread tension according to the base fabric, just as with ordinary fabric. If high-temperature pressing, chemical secondary processing, or printing is carried out, it is necessary to check in advance with offcuts whether there will be any effect on the finishing layer or function.

• For washing methods, prioritize the care label for each fabric and the instructions from the finisher.
• Bleach, strong friction, and excessive heat treatment may affect appearance and functional durability.
• Even if it has a dirt-decomposing function, it does not mean that ordinary washing or dirt removal is no longer necessary.

Differences from Similar Terms

Anti-soil finishing is a finish whose main purpose is to make dirt less likely to adhere or easier to remove. Photocatalytic finishing differs in that it uses light-induced decomposition reactions, but some fabrics have both functions.

Antibacterial and deodorizing finishes are intended to suppress bacterial growth and reduce odors. Photocatalytic finishing may show similar functions, but the mechanism of action, targets, and performance evaluation differ for each finish.

Frequently Asked Questions