What are the key factors affecting the quality of Single PE coated paper sheets?

The key factors affecting the quality of Single PE coated paper sheets involve multiple aspects, including raw material selection, production process, coating technology, environmental conditions, and subsequent processing and storage. The following is a detailed analysis of these key factors:

Raw material quality
Paper base material:
The fiber structure, thickness uniformity, surface smoothness and strength of the paper directly affect the adhesion of the coating and the performance of the final product.
If the paper fiber is too rough or the surface is uneven, the PE coating may not be evenly covered, thereby reducing the water resistance and oil resistance.
PE resin:
The molecular weight distribution, melt index and thermal stability of the PE resin determine the leveling, adhesion and mechanical properties of the coating.
Different grades of PE (such as LDPE, HDPE, LLDPE) have different physical properties, and the appropriate resin type needs to be selected according to specific application requirements.
Additives:
The type and amount of additives such as lubricants, antistatic agents, antioxidants, etc. will affect the performance of the coating, such as reducing friction, improving weather resistance or extending service life.
Coating process parameters
Coating method:
Common coating methods include extrusion coating, roller coating and spraying. Different methods have different effects on coating thickness, uniformity and adhesion.
Extrusion coating is suitable for large-scale production, but requires precise control of temperature and pressure to ensure coating quality.
Coating thickness:
A coating that is too thin may not provide sufficient water and oil resistance; a coating that is too thick may increase costs and affect paper flexibility.
The coating thickness needs to be optimized according to the specific application, usually in the range of 20-50 microns.
Temperature control:

During the coating process, the temperature of the paper and PE resin must be strictly controlled to avoid paper deformation or coating cracking.
Too high a temperature may cause paper curling or PE degradation, while too low a temperature will affect the adhesion of the coating.
Cooling rate:
Cooling too fast may cause stress concentration inside the coating, causing cracking or delamination.
Reasonable cooling rate helps to form a uniform and strong coating.
Coating adhesion
Surface treatment:
The paper surface needs to be corona treated or chemically treated to increase its surface energy, thereby enhancing the adhesion of the PE coating.
If the surface treatment is not appropriate, the coating may fall off or delaminate.
Interfacial compatibility: The interfacial compatibility between paper and PE is an important factor in determining the adhesion of the coating. This problem can be improved by adding coupling agents or other modifiers.
Environmental conditions
Humidity: A high humidity environment may cause the paper to absorb moisture and expand, which in turn affects the flatness and adhesion of the coating.
During production and storage, dry environmental conditions should be maintained as much as possible.
Temperature: Extreme temperatures may cause paper deformation or coating aging. For example, high temperatures may cause PE to soften or even melt, while low temperatures may make the coating brittle.
Pollution: Dust, oil or other pollutants in the production workshop may adhere to the surface of the paper and affect the quality of the coating.
In order to ensure product quality, manufacturers need to conduct comprehensive quality control from the source to the finished product, and continuously optimize production processes and technical solutions according to customer needs.