What is coated paper?

Coated paper, also known as coated printing paper, is called coated paper in Hong Kong and other regions. It is a high-grade printing paper made of base paper coated with white paint. It is mainly used for printing the covers, illustrations, color pictures, advertisements, samples, packaging and trademarks of all kinds of exquisite commodities.

Coated paper is flat paper with dimensions of 787× 1092mm and 880× 1230mm, and the basis weight is 70 ~ 250 g/m? 2。 Coated paper can be divided into single-sided coated paper, double-sided coated paper, matt coated paper and cloth coated paper. According to the quality, it is divided into three types: A, B and C. The main raw materials of coated paper are coated base paper and paint. The requirements for coated base paper are uniform thickness, small flexibility, high strength and good water resistance. There are no paper defects such as spots, wrinkles and holes on the paper surface. The coating used for coating consists of high quality white pigments (such as kaolin, barium sulfate, etc.). ), adhesives (such as polyvinyl alcohol, casein, etc. ) and auxiliary additives. The coating with high fluidity and high solid content is thinly and evenly coated on the base paper by a coating machine, then dried, rolled into a roll on a paper winder, then sent to a super calender for calendering finishing, and finally cut, selected paper and packaged.

Coated paper is characterized by smooth surface, high smoothness and good gloss. The smoothness of coated paper is generally 600 ~ 1000 s because the whiteness of the coating used is above 90%, the particles are extremely fine, and it is calendered by a super calender. At the same time, the pigment is evenly distributed on the paper, showing a pleasant white color. The requirements for coated paper are that the coating is thin and uniform, without bubbles, and the amount of adhesive in the coating is appropriate to prevent the paper from falling powder and hair during printing. In addition, the coated paper should absorb xylene properly.

Coated paper on cloth is pressed with old blankets, which not only makes the paper smooth and white, but also makes the printed graphics and pictures stereoscopic, so this coated paper can be widely used for printing pictorial, advertisement, landscape painting, exquisite almanac, figure photography and so on.

Why use coated paper to print high-grade printed matter?

Coated paper was developed by screen printing. Because the surface of uncoated paper fibers is uneven, which is much larger than the diameter of dots, some dots are just in the gaps between fibers, which can not transfer ink to the paper, making the image pixels unable to reproduce in this part. After the paper is coated with slurry and then calendered, the particles on the surface of the paper are smaller than the diameter of the dot, and the ink absorption of the slurry is better than that of cellulose fiber, so the dot can be reproduced correctly. Obviously, the printing performance of coated coated coated paper is better than that of uncoated offset paper.

The base paper of coated paper adopts high-quality newsprint or offset printing paper, and the high-grade coated paper adopts special base paper. The surface coating is firmly adhered to the base paper. After super calendering, the paper surface coating is firm, without bubbles and streaks, with strong luster and high smoothness. The smoothness of coated paper is generally above 600s, which is 10 times higher than offset paper. In this way, the coated paper can be in close contact with the printing plate, and the printed dot is clear. The pH value of coated paper is about 7, which has no adverse effect on the drying process of lithographic wetting solution and ink. The ink on coated paper adheres quickly and dries quickly. After drying, it can also set off luster, with good dot reproducibility, thin ink layer, clear image and smooth dot. The dimensional stability of coated paper is also better than offset paper. Printing on coated paper can meet the requirements of accurate overprinter. The tensile strength and surface strength of coated paper are also very high, which is enough to resist the large pulling force brought by the used viscous ink film. Due to the above points, coated paper is often used to print high-grade printed matter.

offset paper

Mainly single-sided offset paper. Paper is white and smooth, but its whiteness, compactness and smoothness are lower than coated paper. Super calendered offset paper has better smoothness and compactness than ordinary calendered offset paper. After printing words and patterns, you can paste them into cartons with yellow paperboard.

Photos can use coated paper or offset paper.

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