What Is Coating Finishing?

What is coating finishing?

Coating finishing is a process of uniformly coating one or more polymer compounds on the surface of the fabric and forming a layer or multilayer film on the surface of the fabric through adhesion.

Why is it necessary to finish the coating?

Coating finish can improve the feel, appearance and style of the fabric, and add many new functions to the fabric, such as windbreak, waterproof, moisture permeable, down proof, flame retardant, shading and so on.

More than two thousand years ago, the ancient Chinese people had coated glue on the fabric surface. At that time, they were mostly natural compounds such as lacquer and tung oil, mainly used for making waterproof cloth. In modern times, many synthetic polymer coating adhesives with superior performance have appeared. The original product has a waterproof and impermeable defect. The coated fabric has a stuffy feel and poor comfort when used. In order to improve the aeration and moisture permeability of coating adhesive, since 70s, researchers have developed a series of waterproof and moisture permeable fabric coating adhesive by modifying the chemical structure of coating glue and changing coating processing methods. In recent years, functional coating adhesive and compound coating adhesive have also developed greatly.

　　 Classification and characteristics of coating finishing agents

Coating finishing agent, also known as coating adhesive, is a kind of synthetic polymer with film forming properties. The coating agents have different kinds and their properties are different.

According to chemical structure classification, there are:

1. polyacrylate (PA);

2. polyurethane (PU);

3. polyvinyl chloride (PVC);

4. silicone.

5. synthetic rubber (such as neoprene).

In addition, there are polytetrafluoroethylene, polyamide, polyester, polyethylene, polypropylene and protein. At present, polyesters and polyurethanes are mainly used.

　　 According to the different media used, there are:

According to the different media used in the application, they are divided into two types: solvent type and water type. The solvent type has the advantages of high water resistance, good film forming, fast drying and low solid content, but at the same time, it has strong permeability on fabric, heavy hand feeling, high toxicity, easy ignition, solvent recovery device and high recovery cost.

Compared with the solvent type, the waterborne system is non-toxic, non combustible, safe, low cost, and does not need recycling. It can make thick coated products, which is beneficial to the production of colored coated products and has good hydrophilicity. The drawback is that water resistance is low, baking is slow, and adhesion is difficult on filament fabrics.

According to the coating process and baking conditions, the main classification is as follows:

According to the coating process and baking conditions, there are dry coating adhesive and wet coating adhesive, low temperature crosslinking coating glue and high temperature crosslinking coating glue.

Dry and low temperature crosslinking coating adhesive is the trend of development of coated fabrics in the future due to its simple coating process, low baking temperature, energy saving and energy saving.

Advantages and disadvantages of common coating finishing agents

PU advantages: soft and flexible coating, good strength, can be used for very thin coating; porous, with moisture and ventilation performance; wear resistance, moisture resistance, dry cleaning.

Disadvantages: high cost, poor climate resistance, hydrolysis when encountering water, heat and alkali.

PA advantages: good sunlight resistance and good climate fastness, not yellowing. Transparency and good compatibility are good for producing colored coating products; good washing resistance, strong adhesion and low cost.

Disadvantages: poor elasticity, easy wrinkle, poor surface finish, difficult to adjust the handle properly.

PVC advantages: polyvinyl chloride (PVC) coating agent has excellent comprehensive properties. When plasticizer content is high, it shows high elongation, softness, good handle and abrasion resistance. When the plasticizer content is reduced, its softness and elongation will decrease, and its hardness, tensile strength and wear resistance will increase. It is non-toxic, weather resistant, acid and alkaline resistant, good insulation, easy to dye all kinds of colors, and can be made into transparent, colorless products, especially low price, making it the first choice coating agent for many coated fabrics.

Disadvantages: but its heat resistance is poor, the softening point is 80 degrees, and decomposes and discoloration at 130 C, and precipitates HCI.

Here are some common coatings.

1, PA coating, also known as AC coating, acrylic coating, is currently the most common and most common coating. After coating, it can increase the handle, windbreak and sag.

　　 2, PU coating, that is, polyurethane coating, coated fabric feels full and elastic, and has a film sensation on the surface.

3, anti velvet coating, that is, anti feather coating, coated to prevent fleece fleece, suitable for down jacket fabric. But now the PA coating with water pressure in the coating is also called velvet proof coating.

4, PA white glue coating, that is, the surface of the fabric coated with a white acrylic resin, can increase the coverage of cloth, color, and make the fabric more colourful.

5, PU white glue coating, that is, a white polyurethane resin coated on the surface of the fabric is basically the same as PA white glue. However, after PU white glue is coated, the handle is more plump, the fabric is more elastic and the fastness is better.

　　 6, PA silver coating, that is, coated with a layer of silver white glue on the fabric surface, so that the fabric has the function of shading and radiation protection. It is commonly used for curtains, tents, clothing.

7, PU silver coating, the basic function is PA silver coating. However, PU coated silver fabric has better elasticity and better fastness. For tents and other fabrics requiring high water pressure, PU coated silver is better than PA coated silver.

8, pearlescent coating, through the pearlescent coating on the fabric surface, makes the fabric surface with pearl luster, silver white and color. The costumes are very beautiful. There are also PA pearlescent and PU pearlescent. PU pearlescent is more flatter than PA pearlescent, the film feels better, and has the reputation of "pearl film".

9, glossy coating, smooth surface glossy, generally suitable for making tablecloth tablecloth.

10, silicone high elastic coating, also known as paper feel coating. For thin cotton cloth, it is very suitable for making shirt fabrics. The handle is full, crisp and elastic. It has strong resilience and crease resistance. For thick fabrics, good elasticity and good fastness.

11. Film coating, through pressing and coating on the surface of the fabric, will form a film on the surface of the fabric and completely change the style of the fabric. Generally, the leather surface is made of garments and has a leather coat style. There are two kinds of matte and gloss, and can add various colors into the coating to make the color film. It is very beautiful.

12, flame retardant coating, through fabric dipping or coating treatment, the fabric has flame retardant effect. And can be painted on the fabric surface color or silver. Generally used as curtains, tents, clothing and so on.

13, Teflon three protection treatment, through the fabric with DuPont Teflon treatment, the fabric has waterproof, oil and antifouling function.

14, anti ultraviolet coating, through the fabric anti ultraviolet treatment, so that the fabric has an anti ultraviolet function, that is, to prevent ultraviolet penetration. Generally, light color is difficult to do, and dark color is easier to achieve.

15, there are also special coating for cotton cloth, such as cotton scraping coating, paper feel coating, old coating, hidden coating, oil felt coating, color film coating and so on.