Introduction Of Basic Finishing Process For Common Sweaters

1. Basic finishing process

1. pull width (stentering)

Stretching is the use of cellulose, silk, wool and so on.

In the wet condition, the plasticity can extend the width of the fabric to the required size and make the fabric stable.

Fabric processing before finishing, such as scouring and bleaching, printing and dyeing process, is often subjected to meridional tension, forcing the fabric to warp lengthwise, weft shrinkage, and produce other shortcomings, such as uneven width, uneven edges, rough handle, flat aurora and so on.

In order to make the fabric have a uniform stable door width, and at the same time, it can improve the above shortcomings and reduce the deformation of the fabric in the process of wearing, the general fabric needs to be stretched by finishing after dyeing and finishing.

Two

(pre - Shrinking)

Shrinkage is a physical process to reduce shrinkage of fabric and reduce shrinkage.

In the process of weaving, dyeing and finishing, the fabric will undergo tension and the buckling wave height of the warp will decrease.

When the hydrophilic fiber fabric soaked and soaked, the fibers swelled, and the diameter of warp and weft yarns increased, so that the warp buckling wave height increased, the fabric length shortened, and the shrinkage decreased.

When the fabric is dried, the swelling disappears, but the friction between the yarns still keeps the fabric in a state of shrinkage.

The mechanical shrinkage is to wet the fabric by spraying steam or spray first, then by mechanical extrusion, so that the buckling wave height increases and then loosely dried.

After shrinking, the shrinkage of cotton cloth can be reduced to less than 1%, and the softness of fabric will also be improved due to the extrusion and rubbing between fibers and yarns.

Wool fabric can be loosed and pretreated, and the fabric can be slowly dried in loose state after warm water impregnated or steam injected, so that the warp and weft of fabric can be contracted.

Fabric shrinkage is also related to its organization.

Shrinkage of fabrics is usually assessed by shrinkage.

Three

(CreaSe - reSiSting)

It is called wrinkle proof finishing to change the original composition and structure of fiber, improve its resilience, and make it difficult to wrinkle in the process of taking fabric.

It is mainly used for pure spinning or blending of cellulose fibers, and also for silk fabrics.

The development of crease resistant finishing can be roughly divided into three stages: 1) before the mid 1950s, the crease resistant finishing of urea formaldehyde precursor was mainly used in viscose fabric, so that its size was stable and its shrinkage rate decreased.

2) from the mid 1950s to the mid 60s, the United States began producing non durable cotton fabrics, which had good crease resistance in dry and wet conditions.

Many new finishing agents have also appeared during this period.

3) after the mid 1960s, durable press finishing was developed.

Most of the finished products are polyester and cotton blended fabrics. After pressing, they can heat the synthetic fibers, so they can be kept flat and pleat.

Fabric wrinkle finishing, the recovery performance increased, some strength and serviceability improved.

For example, the wrinkle resistance and dimensional stability of cotton fabrics have been improved obviously. The quick drying and drying properties can also be improved. Although the strength and wear resistance will decrease to varying degrees, it will not affect the wearing performance under normal technological conditions.

Besides the obvious improvement of crease resistance, viscose fabric has a slight increase in fracture strength, especially in wet fracture strength.

But wrinkle resistant finishing has some effect on other related properties, such as fabric elongation at break to varying degrees. Washing resistance is different from finishing agent. The washing fastness of dyed products is improved, but some finishing agents will reduce the fastness of some dyes.

4. heat setting (heat Setting)

Thermal molding is a process that makes thermoplastic fibers and their blended or interwoven fabric relatively stable. It is mainly used for the processing of synthetic fibers and their blended fabrics, such as polyamide or polyester, which are easily constriction and deformation after heating.

The fabric of thermoplastic fiber will produce internal stress in the process of weaving, and it will be prone to wrinkle and deformation under the influence of moisture, heat and external force in dyeing and finishing process.

Therefore, in production (especially wet heat processing, such as dyeing or printing), it is usually treated in a tension state at a slightly higher temperature than the subsequent process, i.e. heat setting, to prevent shrinkage and deformation of fabrics, so as to facilitate the later processing.

In addition, yarns such as stretch yarn (silk), low elastic yarn (yarn) and bulked yarn can be made by using heat setting technology and combining with other physical or mechanical functions.

In addition to improving the dimensional stability, other properties of heat treated fabrics also have corresponding changes, such as wet resilience and pilling properties, which are improved. The elongation of thermoplastic fibers decreases with the increase of heat setting tension, while the strength changes little. If the setting temperature is too high, both of them will decrease significantly.

Two. Appearance

Finishing process

1. whitening (whitening)

The process of increasing the whiteness of textile by using the principle of complementary color is called whitening finishing, also called adding white.

Bleached textiles still contain light yellow substances, and strengthening bleaching will damage fibers.

The whitening agent can make the blue and yellow complement, and improve the whiteness of the textiles without damage to the fibers.

There are two ways to whiten up: blue and fluorescent.

The former uses pale blue dyes or pigments to bleach the fabric to offset yellow. Due to increased absorption of light, the brightness of the fabric will be somewhat reduced and slightly darker.

The fluorescent whitening agent is an organic compound which is close to five colors. When it is dyed to fabric, it is stimulated by ultraviolet rays to produce blue and purple fluorescence. With the reflection of Huang Guangxiang, the whiteness and brightness of the fabric are increased, and the effect is better than that of the upper blue.

Fluorescent whitening can also be combined with bleaching, sizing or crease resistant finishing in the same bath.

2. calendering (Calendering)

Calendering is a process to improve the gloss of fabrics by making use of the plasticity of fibers under hot and humid conditions to flattening or rolling parallel and fine oblique lines on the surface of fabrics.

The calender is composed of several hard rolls and soft rollers with smooth surface.

Hard rollers are metal rollers with highly polished surfaces or dense parallel lines, often with heating devices.

Soft rollers are fiber rollers or polyamide plastic rollers.

After a combination of more and soft rollers, the yarn is flatten, the surface is smooth, the gloss is enhanced, and the feel is tough. It is called leveling.

After the fabric is rolled and pressed by two soft rollers, the yarn wins slightly, the luster is soft, the hands are soft and the B is soft calendering.

Different luster roll combinations and pressure, temperature and wearing mode can give different luster.

Calender finishing is mechanical treatment, and its fabric luster effect is poor. If the fabric first impregnated with the resin and then pre baked, it will get a more durable luster after calendering.

3. grain.

)

Using the plasticity of the fiber, a process of rolling the fabric with a pair of hard, soft, concave and convex rollers with a certain depth pattern at a certain temperature to produce the concave and convex pattern effect is called grain finishing, also known as embossing finishing.

After dyeing or printing, cotton or polyester / cotton blended fabrics can be used to stretch the resin working fluid in the finishing process, thus forming a durable grain effect.

After dyeing and printing, synthetic fabrics can be directly striped.

Using the copper roller with concave grain as the hard roll and the surface high elastic rubber roller as the soft roll pressing and pressing fabric, it is called "flower".

4. grinding and polishing (Sanding)

The process of grinding a short and dense fuzz on the surface of a fabric with a sand roller (or belt) is called finishing.

Arrangement.

The wool fabric has the characteristics of thick, soft and warm, which can improve the wearability of the fabric.

Textured suede or high shrinkage polyester knitted fabric or machine (shuttle) fabric can be made into suede fabric after it is ground.

The base cloth made of superfine synthetic fiber can be used to obtain artificial suede with simulation effect after rolling polyurethane emulsion and sanding.

The effect of finishing (or finishing) is similar to that of fuzzing (or napping), which is to create fuzz on the fabric surface.

The difference is that fuzz finishing is usually made of metal card clothing (woolen cloth is also used for bur), mainly the weft fuzz of the fabric, and its hair is sparse and long.

The finishing can make the warp and weft yarn at the same time to produce the villi, and the villi are short and dense.

In order to control the strength drop of the fabric, the quality of the finished fabric is mainly determined by the density and uniformity of the fuzz.