Detailed Explanation of Water-Based Polyurethane Fabric Coating Processes and Applications
Water-based polyurethane textile coating technology is widely used in the textile industry, with different coating methods suitable for different production needs and product functions. The following details five main water-based polyurethane coating methods, including their principles, advantages, and typical application areas. Dip Coating Dip coating is a basic and effective water-based polyurethane coating process. The principle involves directly immersing the fabric in a water-based polyurethane emulsion. Uniform coating is achieved by controlling the immersion time, temperature, and emulsion concentration. This method is simple, easy to operate, and particularly suitable for small-batch production or experimental research. Dip coating is often used for preliminary experiments on functional textiles, such as the development and testing of waterproof and stain-resistant coatings. Pad-Batch Process The pad-batch process is a continuous coating process, mainly including three steps: padding, drying, and heat curing. First, the fabric is immersed in a bath containing water-based polyurethane using rollers to control the liquid content; then it enters the drying stage to remove water and form a preliminary coating; finally, heat curing promotes the cross-linking of polyurethane molecules, enhancing the strength and durability of the coating. This process is highly controllable and suitable for large-scale continuous production, widely used in clothing fabrics, tents, outdoor products, and other fields. Spray Coating Spray coating utilizes atomization technology to evenly spray the water-based polyurethane emulsion onto the fabric surface, and the coating thickness is controlled by airflow. This method is suitable for fabrics with complex shapes or three-dimensional structures, providing uniform coating distribution and good coverage. Spray coating is often used in products requiring high coating uniformity, such as automotive interiors, protective clothing, and home textiles. Knife Over Roll Coating Knife over roll coating uses a doctor blade to evenly remove excess water-based polyurethane emulsion, thereby forming a coating of precise thickness on the fabric surface. This method offers extremely precise control over coating thickness and is suitable for applications requiring high precision, such as medical protective clothing and precision filtration materials in industrial textiles. Composite Modification Method To improve the performance of water-based polyurethane coatings, composite modification techniques are often employed. Blend modification enhances the weather resistance and abrasion resistance of coatings by blending water-based polyurethane with materials such as acrylates and silanes; nanocomposite technology imparts special properties to coatings by adding functional nanomaterials such as nano-titanium dioxide (for UV resistance) or nano-silver (for antibacterial properties); and crosslinking technology further improves the durabil...
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