Coating processing method
Coating processing methods
There are many different methods of coating processing. Except for the different coating methods, the processing process is the same. The process flow is: base fabric → coating → drying and sintering → cooling and rolling → rolling. Commonly used coating methods in China include the following:
(1) Powder coating method: Put the powdery hot melt adhesive in the funnel, use a scraper to embed the powder in the gap of the card cloth roller, and vibrate the brush to spread the powder on the base cloth. After radiant heating, the hot melt adhesive melts and penetrates into the fibers of the base fabric and is fixed on the fabric surface. . This method causes uneven distribution of hot melt glue and is suitable for low-grade interlinings and temporarily bonded interlinings.
(2) Powder dot coating method: Put the powdery hot melt adhesive in a funnel, use a scraper to embed the powder particles in the holes of the engraving roller until the holes are filled, and heat the engraving roller itself to make the powder particles partially Melted and bonded into a mass. The base fabric is heated by the heating roller and then passes through the engraving roller. Due to heat transfer, the powder is bonded to the base fabric. In this way, the size of the powder balls is the same, and the arrangement is according to the pattern of the engraving roller. The powder points are even and neat, and have a better bonding effect. It is suitable for the production of medium and high-grade interlinings, especially permanently bonded interlinings for woven fabrics.
(3) Slurry point method: First add water and additives to the hot melt adhesive to make a slurry, then use a pump to input it into the rotary screen, and apply the slurry to the base fabric through the scraper in the rotary screen and the holes on the rotary screen. The drying room first dries the slurry to remove moisture, and then melts and sinters it. The pulp point method is more suitable for other medium and high-grade non-woven fusible interlinings and woven fusible interlinings with special requirements.
(4) Double-point method: The double-point method is developed on the basis of the above three coating methods. The basic principle is to consider the different fiber components of the base fabric and the fabric, so their bonding properties are also different. Therefore, two hot melt adhesives with different properties are selected to overlap them. The lower layer is bonded to the base fabric, and the upper layer is bonded to the fabric. Bonding to obtain a more ideal bonding effect. The bonding state is shown in Figure 1-5.
There are currently three methods of double-point coating, namely the double-powder-point method, the double-slurry-point method, and the slurry-point powdering method. Their shapes are shown in Figure 1-6.
The slurry point powdering method is a combination of the slurry point method and the powder dusting method. It is also a commonly used double-point method to produce hot-melt adhesive lining process. It is based on the slurry point method and adds a dusting and suction powder recovery device [ 4]. The basic principle is to superimpose two hot melt adhesives with different properties on the base fabric according to the different bonding properties of the base fabric and the fabric. The lower layer is bonded to the base fabric, and the upper layer is bonded to the fabric to obtain better adhesion. combined effect. During production, first use a rotary screen to coat the slurry points without waiting for the slurry points to dry. Then use the powdering method to sprinkle a layer of hot melt adhesive powder. Some of the powder particles stick to the slurry points, and the other part of the powder particles are not adhered to the slurry points. It is sucked away by the suction powder recovery device and recycled, and then dried and sintered to form a double-layer coating. Its working principle is shown in Figure 1-7 [5]. In the slurry point dusting method, the key is to select the mutual adhesion of the two slurries. Generally, the thermal fluidity of the upper hot melt adhesive should be greater than the thermal fluidity of the lower hot melt adhesive. It is suitable for producing light, thin and soft mid- to high-grade fusible interlining fabrics based on woven fabrics and mid- to high-grade non-woven fabrics. The adhesive interlining produced by the slurry point powder coating process not only has a good hand feel and a high coating amount, but also can be mixed and coated with hot melt adhesive raw materials with different properties, which improves the overall performance of the adhesive interlining [6].
The double-point method is suitable for the production of interlinings with high quality requirements and difficult-to-bond fabrics. Significant progress has been made in the development of double-point special domestic base fabrics and double-point special domestic hot melt adhesives. Ultra-fine base fabrics and elastic base fabrics The development of the fabric has filled the gap in my country’s original base fabrics. The newly developed special base pulp suitable for Chinese double-point interlinings has played a pioneering role in improving the feel of domestic double-point interlinings. In addition, double-point interlinings also have strict requirements for hot-melt adhesives. In recent years, domestic professional hot-melt adhesive manufacturers have developed a large number of special glue types, and have successfully developed a series of PA series with low melting point and soft feel that meet the requirements of double-point interlinings. Special glue, special PES glue, and developed special composite hot melt adhesives such as PES-A and PES-U.
The double-point adhesive lining produced by the slurry point dusting method has its own characteristics: no reverse infiltration phenomenon, uniform coating, that is, small fluctuations in peel strength after bonding, and uniform bonding strength; it can be pressed with steam; and more After the first press, the peeling strength decreases less; it feels soft and has “soft and stiff” characteristics; a thinner base fabric can be used, and the amount of hot melt adhesive can be reduced, reducing costs and reducing pollution. The development of double-point coating technology has improved the overall technology of Chinese interlinings. IwGxrfmWz
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