What is the production process of PU leather base fabric?

As a leading supplier of PU Leather Base Fabric, I am often asked about the production process behind this versatile material. In this blog post, I will take you through the detailed steps involved in creating high - quality PU Leather Base Fabric, from raw material selection to the final product.

Raw Material Selection

The first and most crucial step in the production of PU Leather Base Fabric is the selection of raw materials. The base fabric, which provides the structure and strength, can be made from various materials. One of the commonly used materials is polyester. Our PU Leather Substrate Polyester Fabric offers excellent durability, dimensional stability, and resistance to abrasion. Polyester fibers are known for their high strength - to - weight ratio, which is essential for withstanding the subsequent processing steps and the wear and tear in end - use applications.

Another option is milk silk. Our Milk Silk PU Leather Substrate Fabric is a unique choice. Milk silk fibers are soft, breathable, and have a natural sheen. They add a luxurious touch to the final PU leather product and are also more environmentally friendly compared to some other synthetic materials.

Spinning

Once the raw material is selected, the spinning process begins. In the case of polyester, the polyester chips are melted and extruded through spinnerets to form continuous filaments. These filaments are then drawn and twisted to increase their strength and uniformity. The spinning parameters, such as temperature, extrusion speed, and draw ratio, are carefully controlled to ensure the desired fiber properties.

For milk silk, the milk protein is first extracted from milk. Then, it is blended with other polymers and spun into fibers using a wet - spinning or dry - spinning process. The resulting milk silk fibers are then processed further to improve their mechanical properties and compatibility with the subsequent coating process.

Weaving or Knitting

After the fibers are spun, they are used to create the base fabric through either weaving or knitting. Weaving involves interlacing two sets of yarns at right angles to form a stable fabric structure. Different weaving patterns, such as plain weave, twill weave, and satin weave, can be used to achieve different fabric characteristics. Plain weave is the simplest and most common, providing a balanced and stable fabric. Twill weave gives a diagonal pattern and is often used for fabrics that require more flexibility and drape. Satin weave creates a smooth and shiny surface, which is suitable for applications where a high - end appearance is desired.

Knitting, on the other hand, involves interlocking loops of yarn to form a fabric. Knitted fabrics are generally more stretchy and comfortable compared to woven fabrics. They are often used in applications where flexibility and comfort are important, such as in the production of automotive interiors and clothing.

Pretreatment

Before applying the PU coating, the base fabric undergoes a pretreatment process. This process is essential to improve the adhesion between the base fabric and the PU layer, as well as to enhance the overall performance of the final product. The pretreatment typically includes scouring, bleaching, and heat - setting.

Scouring is used to remove impurities, such as oils, waxes, and dirt, from the fabric surface. This is usually done by soaking the fabric in a solution of detergents and alkali at a specific temperature and time. Bleaching is then carried out to whiten the fabric and improve its color uniformity. Heat - setting is used to stabilize the fabric structure and reduce shrinkage. The fabric is heated to a high temperature under tension, which causes the fibers to relax and set in a new position.

PU Coating

The next step is the application of the PU (polyurethane) coating. There are two main methods for applying the PU coating: direct coating and transfer coating.

In direct coating, the PU resin is directly applied to the pretreated base fabric using a coating machine. The coating machine spreads the PU resin evenly on the fabric surface, and then the fabric passes through an oven to cure the PU resin. The thickness of the PU coating can be controlled by adjusting the coating speed and the amount of PU resin applied.

Transfer coating involves first coating the PU resin on a release paper. The release paper has a smooth surface that allows the PU layer to be easily separated later. After the PU resin is cured on the release paper, the base fabric is laminated onto the PU layer. Then, the release paper is peeled off, leaving the PU layer adhered to the base fabric. Transfer coating can produce a more uniform and smooth surface finish compared to direct coating.

Post - treatment

After the PU coating is applied, the fabric undergoes a series of post - treatment processes to improve its performance and appearance. One of the important post - treatment steps is embossing. Embossing is used to create various patterns on the surface of the PU leather, such as leather grain patterns, which mimic the appearance of natural leather. The fabric is passed through a pair of embossing rollers with engraved patterns at a high temperature and pressure.

Another post - treatment step is surface finishing. This can include applying a topcoat to enhance the abrasion resistance, scratch resistance, and water - repellency of the PU leather. The topcoat can also be used to adjust the gloss level of the surface, from high - gloss to matte finish.

Quality Control

Throughout the production process, strict quality control measures are implemented to ensure that the final PU Leather Base Fabric meets the highest standards. Various tests are conducted, including tensile strength testing, abrasion resistance testing, color fastness testing, and peel strength testing. The tensile strength test measures the maximum force the fabric can withstand before breaking. Abrasion resistance testing evaluates how well the fabric can resist wear and tear. Color fastness testing checks the stability of the fabric's color under different conditions, such as washing and sunlight exposure. Peel strength testing measures the adhesion strength between the PU layer and the base fabric.

Final Inspection and Packaging

Once the post - treatment is completed and the quality control tests are passed, the fabric undergoes a final inspection. The fabric is carefully examined for any defects, such as uneven coating, scratches, or color variations. Any defective products are removed from the production line.

Finally, the qualified PU Leather Base Fabric is rolled up and packaged. The packaging is designed to protect the fabric during transportation and storage. The rolls are usually wrapped in plastic film and labeled with product information, such as product name,规格, and batch number.

Conclusion

The production process of PU Leather Base Fabric is a complex and multi - step process that requires careful control at every stage. From raw material selection to the final packaging, each step plays a crucial role in determining the quality and performance of the final product. As a PU Leather Base Fabric supplier, we are committed to using the latest technology and strict quality control measures to produce high - quality PU Leather Base Fabric that meets the diverse needs of our customers.

If you are interested in our PU Leather Base Fabric products or have any questions about the production process, please feel free to contact us for further discussion and potential procurement negotiations. We look forward to working with you to provide the best solutions for your business.

References

• "Polymer Science and Technology" by Billmeyer, F. W.
• "Textile Processing and Properties" by Horrocks, A. R. and Anand, S. C.
• "Leather Science and Technology" by Covington, A. D.