HOW TO DEAL WITH THE "AURORA" PROBLEM OF POLYESTER FIBER?

    Polyester fibers are made into yarns or fabrics, which will also cause serious "Aurora" problems. The main reason is that polyester fibers in fabrics or yarns will produce total reflection, while fabrics and yarns will produce partial total reflection or partial total diffuse reflection. This leads to the "Aurora" problem. The "Aurora" problem is the extreme of the fabric's luster. For ordinary consumers, the "Aurora" produced by the fabric will cause people to feel uncomfortable. For environmentalists, "Aurora" will cause "light pollution" to nature to a certain extent. ".

    The development of things often has two sides, some manufacturers can use the "Aurora" of polyester fabrics to design flashy clothing and create fashionable fashion. For some manufacturers who do not want polyester "Aurora", the feasible way to remove "Aurora" is through four methods of isotropic fiber, alkali treatment, fabric surface modification and post-treatment.

(1) Shaped fiber

Special-shaped fibers refer to fibers with a non-solid circular cross-sectional shape. The earliest special-shaped fibers were triangular polyester fibers developed and produced as imitation silk fabrics. Later, special-shaped fibers such as three-leaf, five-leaf, and eight-leaf fibers were successfully developed.

The luster of clothing fabrics depends to a certain extent on the luster of the fibers, and the sensory luster of the fibers comes from the geometry of the fibers [21]. The truncated shape of ordinary polyester fiber is circular, and the longitudinal shape is a cylinder with a smooth surface and uniform fineness. According to Geometrical Optics 131, the light reflection of ordinary polyester should follow the following rules: the light reflection along the longitudinal surface of the polyester fiber is total reflection, and the light reflection along the lateral surface of the polyester fiber should be total diffuse reflection.

(2) Alkali treatment

Polyester fiber has a dense structure with hydrophobicity and good alkali resistance, but in a high concentration of lye, especially at high temperature, the molecules of the fiber will be decomposed into terephthalic acid and ethylene glycol and dissolved in water due to the reaction. Due to the etched effect of the lye, tiny spots (grooves and pits) appear on the surface of the fiber, and the diffuse reflection of light is increased to eliminate the "Aurora" of the polyester fiber, and the luster of the fabric tends to be softer, close to silk.

(3) Fabric surface modification

Through surface grafting, the smooth and dense characteristics of polyester surface can be changed into rough and uneven surfaces with different reflection effects; or by introducing new functional groups through grafting, there can be some functional groups with different characteristics on the surface of polyester, and each functional group has different functional groups. photosensitivity varies. So that the polyester fabric has a soft luster.

(4) Finishing of fabrics

The luster of polyester fabrics can be softened by mechanical finishing to achieve the purpose of eliminating "aurora". At present, the gloss finishing of polyester fabrics mostly uses the surface change of the metal roller in the gloss finishing equipment to change the appearance of the polyester surface, such as embossing and calendering and other glossy finishing. Embossing is to use the pattern on the metal roller of the embossing machine to produce a concave-convex pattern effect and a texture-like effect after pressing the fabric to achieve the purpose of eliminating "Aurora". The calendering finishing can be divided into three types: hot pressing, light hot pressing, and cold pressing.