Label paper must meet various requirements, especially considering the diverse applications of label materials. For example, the bottle labels should be perfectly attached to the container and the product should not have any problems in use, but the label should be easily torn off during recycling. At the same time, labels must also be able to withstand the humid environment of beer and bottled water production lines.
In an industrial filling production line, labels are first loaded into a label stack, then quickly taken out by a clamp, coated with glue and then sent to a bottle attaching station. Packed bottles often collide with each other on the assembly line, which may damage the labels. This pressure and friction force have high requirements on the wet strength of the label.
Ideally, the label paper should have the following properties: good calmness, as little curl as possible, the relatively rough back surface, and best tensile and shrinkage properties. For beer and mineral water, the label paper is also required to have higher wet strength. In addition, it also has very low wet expansibility, which means that the label can be accurately positioned without being damaged after being attached to the container.