How to solve the yellowing problem of coated duplex board grey back
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. In this paper, 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