Comparison of the advantages and disadvantages of single-sided coating and double-sided coating

Coating of base paper can be divided into single-sided coating and double-sided coating. Single-side coating is applied to only one side of the base paper, such as single-sided coated paper; double-sided coating is applied to both sides of the base paper, such as double-sided coated paper.

Whether single-coated or double-sided coated paper can be divided into single-layer coating (primary coating) and double-layer coating (secondary coating), and double-layer coating is often used to produce high quality requirements. Coating paper with a large coating amount.

Double-coated paper has better printability than single-coated paper and is an effective method for improving the quality of coated paper.

What are the types of coating machines?

The coating operation is classified into an in-machine type and an out-of-machine type according to the relationship between a coater and a paper machine, and is divided into a single-layer coating and a double-layer coating according to the number of coating times.

In-machine coating is a paper coating machine equipped with a coating machine to make continuous papermaking and coating. External coating is a separate coating machine and a paper machine. The coating machine used for coating operations has a roller. Applicator, air knife coater and blade coater three.

What are the characteristics of roller coating?

Roller coater applies the coating to the paper surface with a coating roller, and the coating is mainly performed in the machine. The amount of coating can be adjusted by measuring the pressure between the rollers, the pressure is strengthened, the throughput of the coating is reduced, and the coating amount is reduced.

The advantage of the roll type double-side coater is that it is simple in construction and can be coated on both sides at the same time. As an in-machine coater, it also has a suitable coating speed, and it is not easy to generate coating streaks. Disadvantageously, the coating thickness of the air knife coater is not easily obtained, and the smoothness and gloss of the knife coater cannot be obtained.

What are the characteristics of air knife coating?

The air knife coater uses the air ejected under pressure to adjust the coating amount and smooth the coating layer, which is referred to as air knife coating. The advantage of air knife coating is that thick coating can be obtained, the coating layer is relatively uniform, and paper breakage is not likely to occur during coating, which is particularly suitable for the coating of pressure sensitive coatings.

However, since the coater of this coater is an invisible air knife, to make the coating uniform and smooth, the paint is required to have a corresponding concentration and twist. The disadvantage is that high solid content coating cannot be performed, and the air knife is susceptible to dryness. Partial blockage of the coating so as to cause coating traces.

What are the characteristics of blade coating?

The principle of the blade coater is basically the same as that of an air knife coater. After the paint is applied to the surface of the paper, the excess paint is scraped and the surface of the coating is smoothed. The difference lies in the scraper coater steel scraper. Coating and flattening.

The advantage of the blade coater is that the coated surface is very smooth and is not affected by the surface condition of the base paper; the paint is not required to be soft and fluid, and high solid content coating and high speed coating can be performed.

The disadvantage is that when the sundries are mixed into the paint, it is easily stuck on the knife edge, leaving a long mark on the paper surface, and the blade is easy to wear. It must be replaced frequently; the coating can not be too thick, and the thickness uniformity of the base paper is required. Also more stringent.