Textile fabric identification method, once you learn it, you will be a master!
Fabric identification can mainly start from three directions, the fabric composition, the front and back sides of the fabric and the warp and weft directions, and the appearance quality of the fabric. By identifying these three directions, we can help fabric buyers find high-quality and low-price products. of good fabric. 1 01 sensory identification method
Main method Looking: using the visual effects of the eyes to observe the completeness, coloring, surface roughness, and appearance characteristics of the tissue, texture and fibers of the fabric; touching by hand: using the tactile effects of the hands to feel the softness, hardness, and hardness of the fabric. Smooth, rough, detailed, elastic, warm and cold, etc. You can also detect the strength and elasticity of fibers and yarns in fabrics with your hands; hearing and smelling: hearing and smell are certainly helpful in inferring the raw materials of certain fabrics. For example, silk has a unique chirping sound; different fiber fabrics have different tearing sounds; polyacrylonitrile fiber and wool fiber fabrics have different smells, etc.
Four steps The second step is to further infer the type of raw materials based on the sensory characteristics of the fibers in the fabric;
Step 1: Preliminarily distinguish the major categories of fibers or fabrics;
The third step is to make a final inference based on the sensory characteristics of the fabric;
The fourth step is to verify the inference results. If you are not sure about the inference, you can use other methods to verify it. If the inference is wrong, sensory identification can be performed again or combined with other methods for identification.
02 Combustion Identification Method Combustion characteristics of common fabric fibers:
, it burns when it encounters fire. It burns quickly and produces a yellow flame with an odor; there is a slight gray-white smoke. It can continue to burn after leaving the fire. After the flame is blown out, there are still sparks that continue to burn, but the continuous time is not long; after burning It can maintain its original velvet shape and easily breaks into loose ash when touched. The ash is gray and soft powder, and the burnt part of the fiber is black;
It burns very quickly, softens, does not melt, does not shrink, produces yellow or blue flames, and has the smell of burning grass; it continues to burn rapidly after leaving the flame; there is little ash, and it is light gray or white grass ash;
It does not burn immediately when it comes into contact with the flame. It curls up first, then smokes, and then the fiber bubbles and burns; the flame is orange and yellow, and the burning speed is slower than that of cotton fiber. It stops burning immediately after leaving the flame. It is not easy to continue burning and may burn hair and feathers. The odor is bad; the ash cannot keep the original fiber shape, but is in the form of amorphous or spherical dark brown brittle pieces that can be crushed when pressed with your fingers. The amount of ash is large and has a burning smell;
Burns relatively slowly, melts and curls, shrinks into a ball when burning, and has the smell of burning hair; it flashes slightly when leaving the flame, burns slowly, and sometimes self-extinguishes; the ash is a dark brown crispy ball, which can be touched with your fingers It breaks when pressed;
Viscose fiber The combustion characteristics are basically similar to cotton, but viscose fiber burns slightly faster than cotton fiber, produces less ash, and sometimes is not easy to maintain its original shape. Viscose fiber will make a slight hissing sound when burning;
It burns quickly, with sparks, melting and burning at the same time, and has a pungent smell of acetic acid when burning; when leaving the flame, it melts and burns at the same time; the ash is black and shiny, irregular blocks that can be crushed with your fingers ;
It burns very quickly, does not melt, does not shrink, and has the smell of burning paper; it continues to burn quickly after leaving the flame; it has less ash and is light gray or off-white;
When it is close to the flame, it causes the fiber to shrink. After contacting the flame, the fiber shrinks rapidly and melts into a transparent gel with small bubbles;
It melts and burns while melting, and the burning speed is fast; the flame is white, bright and powerful, sometimes with a slight black smoke; it has a fishy or spicy smell similar to coal tar; it continues to burn after leaving the flame, but the burning speed is slow; ashes They are dark brown irregular brittle balls that are easy to crush with your fingers;
, when burning, the fiber shrinks rapidly and gradually burns, the flame is very small and almost smokeless; when the fiber is melted in large quantities, a large dark yellow flame will be produced with small bubbles; it will have a very smelly smell of calcium carbide gas when burning; leave The flame continues to burn and sometimes extinguishes itself; the ashes are dark brown irregular brittle beads that can be crushed with your fingers;
Polypropylene It curls while melting and burns slowly; there is a bright blue flame, thick black smoke, and gelatin dripping; there is a smell similar to burning paraffin; it continues to burn away from the flame, sometimes it will self-extinguishes; the ashes are irregular Hard block, transparent, not easy to crush with fingers;
Chlorine It is difficult to burn; it melts and burns in the flame and emits thick black smoke; it extinguishes immediately after leaving the flame and cannot continue to burn; it has an unpleasant pungent chlorine smell when burning; the ashes are irregular dark brown lumps that are difficult to crush with fingers;
Spandex When approaching the flame, it first expands into a circle, and then shrinks and melts; it melts and burns in the flame, the burning speed is relatively slow, and the flame is yellow or blue; when it leaves the flame, it melts and burns, and slowly self-extinguishes; it is very irritating when burning Odor; ash is a white sticky mass.
The identification process of the density gradient method is: first, prepare the density gradient liquid. The preparation method is to properly mix two light liquids and heavy liquids with different densities that can be mixed with each other. Generally, xylene is used as the light liquid, and tetrachloride is used. Carbon is a heavy liquid. Using diffusion, light liquid molecules and heavy liquid molecules diffuse into each other at the interface of the two liquids, causing the mixed liquid to form a density gradient liquid with a continuous change from top to bottom in the density gradient tube. Use standard density balls to calibrate the density values at each height. Then the fibers of the fabric to be tested are pre-treated such as degreasing and drying, and are made into small balls. The small balls are put into the density gradient tube in turn, and the density value of the fiber is measured and compared with the standard density of the fiber to identify the fiber. Type of fiber. Because density gradient fluids change with temperature, it is important to keep the temperature of the density gradient fluid constant during testing.
By observing the longitudinal shape of fabric fibers under a microscope, the major categories to which they belong can be distinguished; by observing the cross-sectional shape of fabric fibers, the specific name of the fiber can be determined.
For pure woven fabrics, when identifying, a certain concentration of chemical reagents should be added to the test tube containing the fabric fibers to be identified, and then the dissolution of the fabric fibers should be observed and carefully distinguished (melted, partially dissolved, slightly soluble, insoluble). And carefully record the temperature at which it melts (melting at room temperature, melting by heating, melting by boiling);
For blended chemical fiber fabrics, when identifying, you need to first split the fabric into fabric fibers, and then separate the fabric fibers Place it on a concave glass slide, unfold the fiber, drop in chemical reagents, and observe it under a microscope to observe the melting of the component fibers and determine the type of fiber;
Since the concentration and temperature of chemical solvents have a significant impact on the dissolving performance of fabric fibers, when using the melting method to identify fabric fibers , the concentration and temperature of chemical reagents should be strictly controlled.
Reagent coloring method is a method to quickly identify fabric fiber types based on the different coloring properties of various fabric fibers to a certain chemical reagent. The reagent coloring method is only suitable for uncolored or purely spun yarns and fabrics. Colored fabric fibers or fabrics must be decolorized first.
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