Study on Technology and Printability of Coated White Paperboard

In general, paper with a basis weight of 200 g/m2 or more and a thickness of 0.1 mm or more is collectively referred to as cardboard. According to its use, it can be divided into four categories: packaging paperboard, industrial technology paperboard, construction paperboard and decorative paperboard. The coated white paperboard belongs to the category of packaging paperboard. It is a processed paperboard made by coating and finishing after coating the white paper on the raw paperboard, and is mainly used for packaging boxes after one-sided color printing.

White cardboard performance characteristics:

The whiteness of the coated surface is higher, the smoothness, the ink absorbency and the printing gloss are all very good, and the cardboard itself has good stiffness and folding-resistance, so that high-quality color printing can be performed on it, and To meet the packaging requirements, it is a high-quality material for high-end commodity packaging. The coated white paperboard is divided into A, B, and C according to different quality levels. When selecting, several aspects such as variety, specification, and quality grade should be considered.

A type whiteboard paper, the use of bleached chemical wood pulp, sulphate wood pulp, mechanical wood pulp, fine waste paper, etc. on the surface and bottom layer, and it has good folding resistance and is used for the production of small cartons;

Type B white paper with bleached chemical pulp or finest white waste paper, waste paper pulp for top and bottom layers;

C-type whiteboard paper uses lower-grade raw materials than B-type whiteboard paper and is no longer produced.

In order to meet the needs of the packaging industry, China annually imports large quantities of coated white paperboard. Although domestic self-sufficiency has increased, the amount of imports continues to increase year after year. In recent years, there have been many improvements in domestic products, but there is still a considerable gap between imported products and flatness, color, uniformity, size, and packaging. Most of the domestic products are poorly printable, mainly due to the poor quality of the base paper, inadequately coated pharmaceuticals, and imperfect post-finishing processes. In the physical properties of cardboard, the stiffness of domestic products needs to be improved, and the uniformity of thickness, weight, and strength needs to be improved.

1 Structure of coated white paperboard

The layer structure of the coated white paperboard is as shown in FIG. 1 and consists of a secondary coating layer, a surface layer, a core layer, a bottom layer, and a one-to-second coating layer. Layers 1 and 5 are coating layers, whose role is to increase the whiteness and printing effect of the coated paper; 2 to 4 layers are sulphate wood pulp, mechanical wood pulp, deinked waste newsprint paper pulp, and its role is to maintain the cardboard The intensity and whiteness. The carton is made of cardboard and piled up. The carton is not squashed because of the strength of the carton; the 3rd layer is mixed waste newsprint pulp, waste magazines, waste corrugated cardboard pulp. Its role is to increase the thickness of the board, reduce the cost of the board and improve the ink absorption of the board.

2 Technical requirements for coated white paperboard

1) Strength. The reason why cardboard becomes cardboard is strength first, which is the basic performance of packaging materials. When used as a packaging material, cardboard is usually made into a carton. It is obvious that the performance of the carton differs from that of the paper bag and must have a solid shape and a certain hardness. For example, the folding lid of a medicinal carton breaks at the fold line after frequent opening and closing, which is related to insufficient folding strength.

2) has a good processing performance. In punching and forming machines, the white paperboard is required to have suitable hardness and cushioning properties, and is easy to die-cut and easy to bond. This is in line with the process requirements for box making.

3) Excellent printability. Adapted to offset and gravure and other printing methods.

4) Because of the proper cushioning and light weight characteristics of white paperboard, it is very beneficial to the protection and transport performance of the package contents.