Purpose of finishing

1. Make the fabric size and shape stable

Stretching - the process of making use of the certain plasticity of cellulose, silk, wool and other fibers under wet conditions to gradually widen the width of the fabric to the specified size and carry out drying and stable finishing, also known as sizing.

Heat setting refers to the process of heat treatment of synthetic fabric under certain tension to make its size and shape stable.

2. Improve the appearance of clothing fabric

Singeing: the fluff on the surface of cotton and its blended fabrics is removed by direct flame burning, so that the surface is smooth and smooth, which is convenient for subsequent processing and ensures product quality.

The flame temperature of singeing is usually 900-1000 ℃, and the surface temperature of hot metal plate is 800 ℃, which is higher than the decomposition temperature or ignition point of various fibers.

Calendering: through the mechanical pressure of calender and the effect of moisture and heat, with the help of fiber plasticity, the surface fibers are arranged in parallel, so as to improve the smoothness of the surface and produce regular reflection of light, so as to improve the color of the fabric.

Rolling finishing: the rolling finishing machine is composed of a heating hard roll and a soft roll. The surface of the hard roller is engraved with a positive pattern, while the surface of the soft roller is engraved with a negative pattern. In finishing, with the help of the plasticity of the fabric in hot and humid conditions, the fabric is rolled by the yin-yang roller to produce concave convex pattern.

Sanding: after finishing, the fabric can produce suede, with improved hand feeling and comfortable wearing. It can be done on the pile drawing machine, and the fabric can produce suede after repeated friction.

3. Improve the hand feel of clothing fabric soft finishing: soft finishing is to make up for the fabric feel stiff and rough defects to make the fabric feel soft. Including mechanical softening finishing, chemical softening finishing and stiffening finishing.

Mechanical softening finishing is mainly to use mechanical method to knead and bend the fabric for many times in tension state, so as to reduce the rigidity of the fabric and restore it to proper softness.

Chemical method is to use softener to reduce the friction coefficient between fibers to obtain softening effect.

Stiffening finishing is to make the fabric smooth, stiff, thick and plump, improve the strength and wear resistance, and also improve the drapery and appearance.

Stiffening finishing is usually carried out in combination with sizing. Softener is added to the slurry to improve the comprehensive handle. Similarly, for simple softening finishing, stiffening agent is added to enhance the body bone.

4. Improve the durability of clothing fabrics

Mothproof finishing

The auxiliaries used in moth proofing finishing should be highly efficient and low toxic, without side effects on human body and affecting all aspects of fabric properties. The commonly used moth proof finishing methods are chemical modification of wool and moth proof agent finishing.

(1) Chemical modification of wool: new and stable cross-linked structure is formed through chemical modification. When moths eat this cross-linked structure, it is difficult to digest and finally kill it, so as to improve the moth resistance.

(2) Moth proofing agent finishing method: wool fiber is directly covered with chemicals that can kill moths by finishing. These chemicals are directly immersed in the cortex of moths, or poisoned through respiratory and digestive organs to make them die.

5. Give the fabric special properties

Common waterproof finishing, water repellent finishing, flame retardant finishing.

Waterproof finishing is to coat the fabric so that neither water nor air can pass through; water repellent finishing is to change the hydrophilicity of the fiber surface into hydrophobicity, so that the fabric is both breathable and not easy to be wetted by water.

Flame retardant finishing, the finished fabric has the ability to prevent the flame spread in varying degrees, and can stop burning quickly after leaving the fire source.

There are three ways of flame retardant finishing: (1) exhaust combustion method: flame retardant is combined with cellulose fiber by ionic bond or covalent bond to make it insoluble in the fiber and obtain durable flame retardant effect. (2) Stock solution method: the flame retardant is directly added into the spinning solution. (3) Copolymerization: the flame retardant is added to the polymer chain segment to make the fabric have qualified fastness to washing, bleaching and perspiration, and not be absorbed by the skin. The first method is mainly used in printing and dyeing plants.