Environmentally friendly sizing | In addition to less use, no PVA, low temperature and low pulp process is equally important

With the improvement of environmental protection requirements and the comprehensive development of new technologies in the textile industry, in the past three years, the progress of sizing technology has not only been shown in the use of PVA slurry, but also in the process technology, and some achievements have been made. . Among them, adopting low temperature slurry sizing and low sizing rate sizing new process technology has significant advantages, not only energy saving, environmental protection, but also suitable for new fiber textile weaving technology system.

1 Basic principle of sizing

The sizing is a kind of textile pulp material used for warp sizing, which is adjusted into a water-dispersible slurry, which is immersed and applied to the warp yarn. After drying, the slurry is bonded between the fibers inside the yarn, and is on the surface fiber of the yarn. The covered slurry acts as a film. The slurry component is mainly composed of a polymer film-forming material, which is supplemented with an auxiliary agent for improving the performance of the sizing yarn, and imparts a role of reinforcing the warp yarn to stretch, wear, and stick hairiness.

2 low temperature slurry sizing process

The key to low temperature slurry sizing is low temperature. The traditional high-temperature sizing process is high-temperature cooking slurry and high-temperature slurry sizing. Raw materials such as starch slurry are slowly put into cold water, uniformly stirred, heated to above 95 °C, and then concentrated into the slurry tank for heat preservation. The process temperature of low temperature slurry sizing refers to the temperature range from normal temperature (room temperature) to the traditional high temperature sizing process temperature, which can be divided into three small domains: medium high temperature, medium temperature and normal temperature.

Low temperature sizing slurry temperature zone

Low temperature slurry sizing needs to solve the following problems: at lower temperatures, materials such as starch slurry can be slurried and uniform, no need to boil at high temperature, or high temperature maintenance after high temperature cooking; at lower temperatures, the slurry does not hard to occur. Flowing, impervious, and even freezing; at lower temperatures, the original cotton fiber wax does not hinder the penetration of the slurry into the warp yarn. Therefore, the low-temperature sizing process requires a change in the properties of the slurry to form a factor that is favorable for low-temperature sizing: the slurry molecules have more hydrophilic groups, can be dispersed in water at a lower temperature, and do not reversely aggregate; The molecular weight of the slurry is lowered to obtain low-temperature fluidity, and the wettability of the slurry is improved by adjusting factors such as surfactant, pH and the like.

The low temperature slurry sizing process does not require high temperature cooking and heat preservation, which can save steam energy. With the development of new fiber textiles, such as hemp, colored cotton, bamboo pulp fiber, TencelTM, Modal, soy protein fiber, milk protein fiber, pearl fiber and other warp yarn products, it is easy to suck, no It is resistant to damp heat, easy fibrillation, high temperature and hardening for a long time, and the advantages of lowering temperature sizing can be directly reflected in the sizing, weaving process and fabric quality. In general, high-temperature and medium-temperature sizing methods are used to treat such products, and in some studies, the sizing rate is also reduced.

Low-temperature slurry preparation is still based on the principle of using environmentally friendly slurry without PVA. Slurry preparation and sizing of low-temperature slurry sizing process are divided into two schemes: starch-based solution, medium-high temperature and medium-temperature sizing, low sizing rate; synthetic slurry-based solution, medium temperature, room temperature sizing, low sizing rate.

3 low sizing rate sizing process

The sizing rate is the ratio of the dry weight of the slurry adhered after the warp sizing to the dry weight of the warp yarn. The low sizing rate means that the sizing rate of the warp yarn is generally 10% to 50% lower than the conventional sizing rate, or even more. As a low sizing rate sizing, the strict definition refers to the non-sizing factor that excludes the fiber raw material and the yarn structure, and the sizing rate reduction effect obtained only by the slurry type and the sizing process technology is called a low sizing rate sizing process.

Under the sizing performance conditions at which the high sizing rate is maintained, the lower sizing rate sizing needs to impart better adhesion film forming properties to the main factors that determine the adhesion. Since the relative molecular weight of the slurry is relatively high, the bonding force is at a high position, so that the adhesion strength can reduce the sizing rate; when the slurry has a strong bonding group on the molecular chain, the bonding force is large, and the sizing rate can also be lowered.

The sizing rate is reduced, and it is easy to lightly fluff and, in severe cases, cannot even weave. However, the sizing rate is too small to have the advantage: in addition to the cost reduction, it can solve the problems of driving crossbars, serious breaks in the dry twisting and twisting, and reduce the number of twill-printed fabrics. The low sizing rate sizing process can be mainly divided into the following three types: by low-degradation control of the molecular weight of starch denaturation, with an auxiliary agent for improving the wetting property of the starch slurry, and an additive for improving the adhesion of the serosa film, the sizing rate can be remarkably reduced; In the sizing of pure cotton, polyester-cotton and pure polyester warp yarns, the use of acrylic copolymer emulsion slurry can not only reduce the sizing rate, but also can be applied to low temperature at room temperature when sizing less components; for tightly woven yarns such as compact spinning and siro spinning The line can be sizing with a low sizing rate, and the slurry formulation and sizing method can be carried out according to the conventional high-temperature boil sizing method or a new method.