There's a close relationship between viscosity control of textile chemical powder-pree paste and uniformity during the fabric padding process. This adaptability isn't based on a fixed value; rather, it's achieved through dynamic viscosity adjustment, tailored to the requirements of the entire padding process. From the additive's flow characteristics and fabric adsorption to equipment operating parameters, this creates a synergistic effect to ensure uniformity. The core requirement of fabric padding is continuous and uniform adhesion of the additive to the fabric surface and interfiber spaces, avoiding problems such as streaking, missed coating, and localized accumulation. As a paste-like additive, the viscosity of textile chemical powder-pree paste directly determines its flowability, permeability, and fabric bonding efficiency during the padding process. Therefore, viscosity control is crucial for achieving uniformity.
In the first step of the padding process, when the fabric enters the padding tank and comes into contact with the textile chemical powder-pree paste, optimal viscosity directly impacts the wetting of the additive. If the viscosity of a textile chemical powder-pree paste is too low, its fluidity is too high. As the fabric passes rapidly through the padding tank, it may not form a stable coating on the fabric surface. Some additives may be lost as the rollers rotate, or due to rapid penetration, they may be concentrated in the inner layers of the fabric, resulting in insufficient surface additives. Furthermore, too low a viscosity can lead to uneven distribution of additives between the rollers, particularly at the ends and in the middle of the rollers. Pressure differences can cause additive accumulation or loss, ultimately resulting in uneven light and dark marks on the fabric. Conversely, if the viscosity of a textile chemical powder-pree paste is too high, its fluidity is significantly reduced, making it difficult to spread evenly with the movement of the fabric in a short period of time. Accumulation can easily occur at the warp and weft intersections of the fabric or on raised surfaces, while blocked flow may result in leaks in recessed areas. Especially for densely structured fabrics, the high-viscosity powder-pree paste cannot penetrate the interfiber spaces and remains on the surface, resulting in an uneven distribution of additives between the inner and outer layers, affecting the uniformity of subsequent finishing.
Viscosity control of textile chemical powder-pree pastes also needs to be tailored to the operating characteristics of the padding equipment to offset external factors that interfere with uniformity during processing. During the padding process, roller pressure, rotational speed, and fabric speed generate varying shear forces, which can alter the paste's viscosity. If the paste's viscosity is insufficiently stable, high shear forces can cause a sudden drop in viscosity, leading to additive loss. Meanwhile, in low-shear areas, the viscosity can rebound, causing accumulation. Therefore, viscosity control involves adjusting the formulation of the textile chemical powder-pree paste, such as selecting appropriate thickeners and stabilizers, to ensure the paste maintains a relatively stable viscosity under varying shear conditions. This prevents viscosity anomalies caused by fluctuations in equipment operating parameters and ensures uniform distribution of the additive on the fabric. For example, for high-speed padding lines, the viscosity of the powder-pree paste is controlled within a range more suitable for rapid flow. This ensures that the additive can move quickly with the fabric and adhere evenly, while also preventing additive residue or dripping from the rollers due to excessive speed.
Furthermore, the viscosity of textile chemical powder-pree paste must be adjusted based on the fabric's material and structural characteristics to achieve targeted uniformity. Different fiber types have different adsorption capacities and penetration requirements for additives. For example, cotton fabrics are highly hygroscopic and require a powder-pree paste with a moderate viscosity to ensure sufficient penetration without wasting additives or making the fabric feel hard due to excessive penetration. On the other hand, synthetic fabrics have a smooth surface and low hygroscopicity. If the viscosity is too low, the additive will easily slide off the surface. Therefore, the viscosity of the powder-pree paste needs to be controlled within a slightly higher range to enhance adhesion to the fabric surface and form a uniform film. In fabric structures, loose knitted fabrics have large interstices, and low-viscosity powder-pree pastes can quickly penetrate and drain through these interstices. Therefore, the viscosity needs to be increased to slow penetration and ensure uniform distribution of the additive across the surface and interior. On the other hand, dense woven fabrics require a powder-pree paste with a slightly lower viscosity to help it penetrate the tight interfiber structure and achieve uniform penetration.
In actual processing, viscosity control of textile chemical powder-pree pastes is verified through preliminary sample testing to ensure uniformity under specific padding conditions. By simulating actual padding parameters and observing the adhesion, penetration depth, and post-drying appearance of the powder-pree paste on the fabric, the viscosity can be fine-tuned to ensure uniformity not only within a single run but also across batches, avoiding fluctuations in processing results due to viscosity differences between batches. This dynamic viscosity control based on actual needs enables textile chemical powder-pree paste to precisely adapt to the various requirements of fabric padding processing, fundamentally ensuring the uniform distribution of additives on and within the fabric surface, providing a stable foundation for subsequent functional finishing (such as waterproofing, anti-wrinkle, antibacterial, etc.), and ultimately achieving consistency and reliability in fabric product quality.
