Textile fabrics are primarily categorized based on manufacturing methods into Woven Fabric and Knit Fabric, as well as the emerging Non-Woven technology. The general process for the main manufacturing methods includes: 1. Synthetic fibers, 2. Yarn production, 3. Weaving, 4. Dyeing and finishing, 5. Packaging. Woven fabrics are created by interlacing two or more sets of yarns at right angles to each other, with the longitudinal yarns known as warp and the horizontal yarns known as weft. Due to the perpendicular interlacing of yarns in woven fabrics, they possess characteristics of strength, stability, and relatively low shrinkage rates.
Common types of woven fabrics include:
Pique fabric: The surface of the fabric is porous, like a honeycomb. It is more breathable, dry and durable than ordinary knitted fabric.
Terry cloth: The bottom surface is like a towel loop. It is made of 80% cotton + 20% polyester fiber. It is warm, soft. The appearance and feel are relatively warm. It is mostly used in coats or T-shirts. Fleece fabric: The bottom surface is like a towel loop. It is made of cotton yarn texture. The fabric surface is like terry cloth. It is warm, durable, soft, sweat-absorbent and thick. It is mostly used for sportswear and autumn and winter styles. Wafer fabric: The surface of the fabric is in the shape of wafers with strong three-dimensional effect. It is easier to deform after washing. Polyester mercerized double-sided fabric: It does not contain cotton. It is close-fitting and shows lines. It is airtight and easy to snag. Flannel fabric: After being brushed, the surface layer is cut to achieve a napped effect. It is made of 80% cotton + 20% polyester fiber. It is warm, has good elasticity, can be machine-washed, is smooth and soft, and will generate static electricity. It is mostly used for coats. Modern dyeing and printing is mainly divided into scouring and bleaching, dyeing, printing and finishing according to the variety, specification and finished product requirements of fabrics. Scouring and bleaching: Natural fibers all contain impurities. In the textile processing process, various sizing agents, oil agents and contaminated dirt are added. The existence of these impurities not only hinders the smooth progress of dyeing and finishing processing, but also affects the wearing performance of fabrics. The purpose of scouring and bleaching is to use chemical and physical mechanical actions to remove impurities on the fabric, make the fabric white and soft, have good permeability, meet wearing requirements, and provide qualified semi-finished products for dyeing, printing and finishing. The main processes of scouring and bleaching of pure cotton fabrics: 1. Preparation of grey fabric. 2. Singeing. 3. Desizing. 4. Boiling. 5. Bleaching. 6. Mercerizing. 01 Preparation of grey fabric: Preparation of grey fabric includes inspection of grey fabric, turning over fabric, batching, boxing, printing and sewing head. The purpose of inspecting grey fabric is to check the quality of grey fabric and solve problems in time. The inspection content includes two items: physical indicators and appearance defects. The former includes the length, width, weight, density and strength of warp and weft yarns of grey fabric. The latter includes spinning defects, weaving defects, various stains and damages. Usually about 10% of the total is spot-checked. After inspecting grey fabric, the grey fabric must be batched, boxed and printed on the cloth head, indicating the variety, processing technology, batch number, box number, release date and code of the person who turns over the fabric for easy management. In order to ensure continuous batch processing, the grey fabric must be sewn. 02 Singeing: The purpose of singeing is to burn off the fluff on the fabric surface to make the fabric surface smooth and beautiful, and prevent uneven dyeing and printing defects caused by the existence of fluff during dyeing and printing. Fabric singeing is to quickly pass the fabric flat through high-temperature flame or rub over the red-hot metal surface. At this time, the fluff on the fabric surface quickly heats up and burns. The fabric body is relatively tight and heats up slowly. Before reaching the ignition point, it has left the flame or red-hot metal surface, so as to achieve the purpose of burning off the fluff without operating the fabric.To ensure smooth weaving, textile mills often size the warp yarns to enhance strength and wear resistance. The sizing on the greige fabric affects the fabric’s water absorption and the quality of dyed and finished products, as well as increases the consumption of dyeing and chemical agents. Therefore, it is necessary to remove the sizing before scouring, a process known as desizing. Sizing on cotton fabrics can be removed through alkali desizing, enzyme desizing, acid desizing, and oxidizing agent desizing.
Alkali desizing causes the sizing to swell, reducing its adhesion to the fibers, and is then removed by washing with water. Enzymes, acids, and oxidizing agents degrade starch, increasing its solubility in water, and are removed by washing. Due to the significant damage acids and oxidizing agents can cause to cotton fibers, they are rarely used alone and are often combined with enzyme and alkali desizing. During the growth of cotton fibers, natural impurities such as pectin, waxy substances, nitrogenous materials, and others coexist. After desizing, most of the sizing and some natural impurities have been removed from the cotton fabric, but a small amount of sizing and most natural impurities remain. The presence of these impurities makes the fabric surface yellowish and less permeable. Additionally, the presence of cotton seed shells significantly affects the appearance quality of the cotton fabric. Therefore, it is necessary to boil the fabric in a concentrated alkali solution at high temperatures for a longer period to remove residual impurities. Scouring utilizes caustic soda and other scouring aids to chemically degrade or emulsify pectin, waxy substances, nitrogenous materials, and cotton seed shells, and then removes the impurities from the fabric through washing. After scouring, cotton fabrics still contain natural pigments, making their appearance not white enough for dyeing or printing, which affects the brightness of the colors. The purpose of bleaching is to remove pigments and impart the necessary and stable whiteness to the fabric without significantly damaging the fibers. Common bleaching methods for cotton fabrics include sodium hypochlorite method, hydrogen peroxide method, and sodium chlorite method. The sodium hypochlorite bleaching solution has a pH value of around 10 and is performed at room temperature with simple equipment, convenient operation, and low cost, but it causes significant damage to the fabric strength and results in lower whiteness. The hydrogen peroxide bleaching solution has a pH value of 10 and is performed at high temperatures, resulting in high and stable whiteness, good hand feel, and the ability to remove sizing and natural impurities. The disadvantage is the high demand for equipment and higher costs. Under appropriate conditions, it can be combined with caustic soda to complete desizing, scouring, and bleaching in one step. The sodium chlorite bleaching solution has a pH value of 4-4.5 and is performed at high temperatures, offering the advantages of good whiteness and minimal fiber damage, but it is prone to producing toxic gases during bleaching, causing environmental pollution and equipment corrosion. The equipment requires special metal materials, thus its application is somewhat limited.Both sodium hypochlorite and sodium chlorite bleaching require dechlorination to prevent damage to the fabric due to residual chlorine during storage.
Mercerization refers to the processing process of treating cotton fabrics with concentrated caustic soda solution at room temperature or low temperature under tension in both warp and weft directions to improve fabric properties. After mercerization, due to fiber expansion, the natural twist of the fiber in the longitudinal direction disappears, the cross-section becomes oval, and the reflection of light is more regular, thus enhancing the gloss. The increase in the amorphous region of the fiber increases the dye uptake rate during dyeing. The improvement of orientation increases the fabric strength and also has a shaping effect. After mercerization, methods such as washing with water to remove alkali, using a steaming box to remove alkali, or flat washing to remove alkali must be used to fully remove alkali until the fabric is neutral. Dyeing is a processing process in which dyes are physically or chemically combined with fibers or pigments are generated on fibers by chemical methods to give the entire textile a certain color. Dyeing is carried out under certain conditions such as temperature, time, pH value, and required dyeing auxiliaries. Dyed products should have uniform color and also have good color fastness. The dyeing methods of fabrics are mainly dip dyeing and pad dyeing. Dip dyeing is a method in which the fabric is immersed in the dye solution and the dye gradually dyes the fabric. It is suitable for small batch and multi-variety dyeing. Rope dyeing and jig dyeing belong to this category. Pad dyeing is a dyeing method in which the fabric is first immersed in the dye solution, then passed through rollers to evenly press the dye solution into the fabric, and then processed by steaming or heat fusion. It is suitable for dyeing large quantities of fabrics. There are many methods for printing patterns on fabrics with dyes or pigments, but the main methods are as follows. 1. Direct printing. The method of directly printing various color flower patterns on the fabric is direct printing. During the printing process, the color pastes of various colors do not interfere or damage each other. About 80%-90% of printed fabrics use this method. This method can print white ground flowers and full ground flower patterns. 2. Discharge printing. Printing colored patterns on fabrics with ground colors using color pastes containing chemicals that can destroy the ground colors. Such chemicals are called discharge agents. Dyes resistant to chemicals can also be added to the discharge paste. Thus, discharge printing can achieve two effects, namely discharge white and color discharge. 3. Resist printing. First, printing a resist agent on the fabric that can prevent the dye from dyeing, then pad dyeing the ground color. The printed pattern can prevent the ground color from dyeing. This method is resist printing. This method can achieve three effects, namely resist white, color resist and partial resist.The organization of textile finishing processes plays a crucial role in developing fabrics with special functions, endowing them with unique functional and wearable effects.
As technology advances, new processes and technologies in finishing will continue to emerge.
