How To Solve Coated Duplex Board Grey Back Becoming Yellow

Duplex board is one kind of paperboard. It is called duplex board because it is made up of two layers, or plies. The exterior of the board is very often coated to make it more water-resistant and to give it a glossy sheen.

Duplex board is tough, thin and able to take on a bright white appearance, unlike common corrugated cardboard. It is commonly used to create boxes for a variety of small goods. For example, it is often used in pharmaceutical packaging. It is also used to make garment boxes and cigarette packs, paper plates and cups, and in the food industry.

Milk cartons can be made out of duplex board, and wines and liquors packaged in boxes may be inside duplex board containers. Duplex board used in the food industry is not made from recycled paper for hygiene reasons, but sometimes waste paper is used when the board is designated for other purposes.

Other common uses for duplex board is match boxes, book covers, and greeting cards. This kind of duplex board is relatively lightweight.

Reversion phenomenon coated duplex board grey back has seriously affected the appearance of the packaging material.

Duplex board grey back yellowing means that the product is stored after a certain time, or by the sunlight, its whiteness there will be some decline phenomenon. 

Reversion phenomenon and study the mechanism of occurrence of coated duplex board grey back to find out the yellowing of the measures and methods of the various factors and stable whiteness, has drawn our attention. Combined with our production practice, coated duplex board grey back yellowing phenomenon analysis, on how to prevent and solve the yellowing phenomenon for a study.

First, the coated duplex paper board yellowing phenomenon formation mechanism.

The latest research results show that the reversion phenomenon duplex cardboard during storage and after exposure to sunlight, the duplex board surface material reacts with oxygen in the air, changing the chemical structure of the surface material, thus affecting the human visual effects. The degree of oxidation determines the severity of yellowing. Oxidation process is mainly due role in promoting the following three factors: ① high temperature, ② ultraviolet light, ③pH value.

Second, coated duplex board grey back yellowing phenomenon of factors

Analysis of the factors that constitute the catalyst for the oxidation process and coated duplex paperboard material impact coated duplex paperboard yellowing phenomenon has the following main aspects: paper coated duplex board, optical brighteners, color pigments, coating cloth adhesive.

2.1 coating base

2.1.1 Paper fiber types and composition: mainly composed of the surface layer of the fiber. Original pulp paper coated duplex

board is generally composed of bleached chemical pulp composition, and therefore the base paper is mainly due to yellowing 

caused by heat-induced yellowing. Mechanical pulp reversion mainly light-induced yellowing, so during storage than chemical pulp reversion more serious.

2.1.2 Paper pH: acidic cardboard is easier than in a basic cardboard cause yellowing.

2.1.3 Other raw materials base paper: such as adding fill material, retention agents raw materials have little impact