How to identify the quality of the fabric? I believe that this is the most troublesome problem for many new textile people, especially procurement, and its professional knowledge is insufficient. Textile fabric identification can mainly start from three directions: textile fabric composition, textile fabric front and back and warp and weft direction, textile fabric appearance quality, through the identification of these three directions, can help fabric buyers to find good inexpensive fabric.

Identification of components

Sensory discrimination

(1) Main methods:

Eyes: Use the visual effect of the eyes to watch the luster of the fabric, dyeing, surface roughness or not, and the appearance characteristics of the organization, texture and fiber.

Hand touch: Use the tactile effect of the hand to feel the fabric soft and hard, smooth, rough, fine and clean, elastic, cold and warm. The strength and elasticity of the fibers and yarns in the fabric can also be detected by hand.

Hearing and smelling: Hearing and smelling are helpful in judging the raw materials of some fabrics. For example, silk has a unique silk sound; The tearing sound of different kinds of fiber fabrics is different; The smell of acrylic fiber and wool fiber fabric is different.

(2) Four steps:

DiYi step: preliminarily distinguish the categories of fibers or fabrics;

The second step: according to the sensory characteristics of the fibers in the fabric, further judge the type of raw materials;

Step 3: Make the final judgment according to the sensory characteristics of the fabric;

Step 4: Verify the judgment results. If the judgment is not sure, other methods can be used to verify. If the judgment is wrong, sensory identification can be re-performed or combined with other methods for identification.

Combustion identification

Combustion characteristics of common textile fibers:

① Cotton fiber, in case of fire, burning, burning speed, yellow flame, smell; Slightly gray smoke, after the fire can continue to burn, after blowing out the flame there is still a spark in the flame, but the duration is not long; After burning, it can maintain the shape of the original velvet, and it is easy to break into loose ash when touched by the hand. The ash is a gray soft powder, and the burnt part of the fiber is black.

(2) Hemp fiber, burning fast, softening, not melting, not shrinking, producing yellow or blue flame, there is the smell of burning grass; Leave the flame to continue burning rapidly; Less ash, light gray or white grass dust.

(3) Wool, contact with the flame does not burn immediately, first curling, after smoking, and then fiber foaming burning; The flame is orange yellow, the burning speed is slower than the cotton fiber, the flame stops burning immediately after leaving, it is not easy to continue burning, and the smell of burning hair and feathers; The ash can not maintain the original fiber, but is an amorphous or globular glossy black brown crisp block, crushed with a finger pressure, the amount of ash is more, there is the smell of burning.

④ Silk, burning relatively slow, melting and curling, burning into a ball, there is a smell of burning hair; Slightly shimmering when leaving the flame, slowly burning, sometimes self-extinguishing; Gray is a black brown crunchy ball, crushed with a finger.

⑤ Viscose fiber, the burning characteristics are basically similar to cotton, but viscose fiber burning speed is slightly faster than cotton fiber, less ash, sometimes not easy to maintain the original shape, viscose fiber burning will emit a slight sizzle.

⑥ Acetate fiber, burning speed, spark, while melting, burning, burning with pungent acetic acid taste; When it leaves the flame, it melts and burns; Gray is a black glossy irregular lump that can be crushed with the fingers.

7 Copper ammonia fiber, burning fast, no melting, no shrinkage, there is a burning paper smell; Leave the flame to continue burning rapidly; Less ash, light gray or gray white.

⑧ Nylon, when close to the flame causes fiber shrinkage, contact with the flame, the fiber rapidly crinkles, and melts into a transparent glue, while there are small bubbles.

⑨ acrylic fiber, while melting and melting, burning, burning speed; The flame is white, bright and powerful, sometimes slightly black smoke; Having a fishy odor or acrid taste similar to coal tar; Leave the flame to continue burning, but the burning speed is slow; The ash is a black brown irregular brittle ball, easy to break with fingers.

⑩ When burning, the fibers shrink rapidly, burn slowly, the flame is very small, almost smokeless; When a large amount of fiber melting will produce a large dark yellow flame, there are small bubbles; When burned, it has a special odor of calcium carbide gas; Leave the flame to continue burning, sometimes self-extinguishing; The ash is black brown irregular brittle beads, which can be broken with fingers.

⑪ Polypropylene fiber, while shrinking, melting, slow burning; There was a bright blue flame, with black smoke coming from it, and a jelly dripping down; Has a smell similar to burning paraffin; Leave the flame to continue burning, sometimes self-extinguishing; The ash is irregular hard block, transparent, and is not easy to break with fingers.

Chlorine fiber, difficult to burn; Melt and burn in the flame, emitting black smoke; Leave the flame immediately extinguished, can not be continued; An unpleasant acrid chlorine odor during burning; The ash is an irregular black brown lump, which is not easy to break with fingers.

When the spandex approached the flame, it would first expand into a circle and then shrink and melt. Molten combustion in the flame, the burning speed is relatively slow, the flame is yellow or blue; Leave the flame side melting side burning, slow self-extinction; Special pungent smell when burning; The ash is a white sticky mass.

Density gradient method

The identification process of density gradient method is: First of all, the density gradient liquid is configured. The configuration method is to mix the light liquid and the heavy liquid with two different densities and can mix with each other properly. Generally, xylene is used as the light liquid and carbon tetrachloride is used as the heavy liquid. The density values of each height are calibrated with balls of standard density. Then the textile fiber to be tested is deoiled, dried and other pretreatment, made into small balls, the balls are successively put into the density gradient tube, the density value of the fiber is determined, compared with the standard density of the fiber, so as to identify the type of fiber. Because the density gradient fluid changes with temperature, it is important to keep the temperature of the density gradient fluid constant when testing.

microscopy

By observing the longitudinal morphology of textile fibers under microscope, we can distinguish the categories to which they belong. By observing the cross-sectional shape of textile fibers, the specific types of fibers can be determined.

Dissolution method

For pure textile fabrics, when identifying, a certain concentration of chemical reagents should be added to the test tube containing textile fibers to be identified, and then observe and carefully distinguish the dissolution of textile fibers (dissolved, partially dissolved, slightly dissolved, insoluble), and carefully record the temperature at which it is dissolved (dissolved at normal temperature, dissolved by heating, dissolved by boiling).

For blended fabrics, when identifying, it is necessary to first split the fabric into a root of textile fibers, and then put the textile fibers on a concave slide, unfold the fibers, drop chemical reagents, and observe under a microscope, from which the dissolution of the component fibers is observed to determine the type of fibers.

Since the concentration and temperature of chemical solvents have a relatively obvious effect on the solubility of textile fibers, the concentration and temperature of chemical reagents should be strictly controlled when identifying textile fibers by dissolution method.

Reagent staining

Reagent coloring method is a method to quickly identify textile fiber varieties according to the different coloring properties of various textile fibers to a certain chemical agent. Reagent coloring is only applicable to undyed or pure spun yarn and fabrics. Colored textile fibers or textile fabrics must be advanced decolorized.

Identification of front and back and longitude and latitude

Textile fabric front and back identification

It can be roughly divided into identification according to the organizational structure of textile fabrics (plain, twill, satin), identification according to the appearance effect of textile fabrics (printed fabric, gauze fabric, towel fabric), identification according to the pattern of textile fabrics, identification according to the edge characteristics of textile fabrics, identification according to the appearance effect of textile fabrics after special finishing (raised fabric, double-layer fabric, multi-layer fabric, etc.). Rotten fabric), according to the trademark and seal identification of textile fabric, according to the packaging form of textile fabric identification.

Identification of warp and weft orientation of textile fabrics

It can be identified from the edge of the textile fabric, the density of the textile fabric, the raw material of the yarn, the twist direction of the yarn, the structure of the yarn, the sizing situation, the reed mark, the warp and weft of the fabric, the twist direction and twist, and the flexibility of the fabric.

Identification of appearance quality

Textile fabric defect identification

The defects of textile fabrics are broken warp, heavy yarn, jumping, gaping, cobweb, broken holes, roving, slub yarn, big belly yarn, double weft, tight twist yarn, dry uneven, thin, thin, dense road, Thick section, edge, cotton knot impurity, spot stains, color bar, cross, off pick, foot, crease, rolling, damage, wrong pick, loose warp, reed path, reed wrong, narrow width, reverse twill, pattern inconsistency, color difference, color bar, stripe, stripe, pattern inconsistency, depth and fine points, skew, print deviation, pulp, color flower, stain these defects, according to the appearance characteristics can be identified.

Identification of deteriorated textile fabrics

The main methods are seeing, touching, hearing, smelling, licking:

Look: Observe the color and shape of the fabric, and there are no traces left by deterioration. Such as wind stains, oil, water spots, mildew spots, stains, discoloration or normal different characteristics of the fabric.

Touch: Grip the fabric with the hand, feel whether there is stiffness, damp sticky, fever and other symptoms of deterioration.

Listen: the sound produced by tearing the fabric is compared with the crisp sound produced by the normal fabric, such as dumb, cloudy, silent, may deteriorate.

Smell: By smelling the fabric, to determine whether the fabric deteriorates. In addition to specially finished fabrics (such as coating rainproof agents or resin treatment, etc.), any odor that has a strange smell, such as acid, mold, bleaching powder, etc., indicates that the fabric has deteriorated.

Licking: After licking the fabric through the tongue, if there is flour mold or sour taste, it means that it has been moldy, learn these methods, it is not a rookie fabric, identify the fabric that is a minute thing.