Why is BOPP color synthetic paper prone to curling or deformation when printed?

BOPP color synthetic paper is prone to curling or deformation during printing, which is mainly caused by the following factors:

1、 Characteristics of paper itself

Humidity and temperature sensitivity:

BOPP colored synthetic paper is sensitive to changes in humidity and temperature. When the humidity of paper increases to a certain value, the paper will loosen and even become fragments or pulp. At the same time, temperature changes can also affect the equilibrium moisture content of paper, thereby affecting its dimensional stability.

In the production process of paper plastic composite, when the paper and BOPP film pass through the hot pressing mechanism, the moisture contained in the paper evaporates under the hot extrusion of the heating roller, causing the fibers to dry and shrink, and the paper size to decrease.

Paper texture and structure:

The texture and structure of paper can also affect its resistance to curling. Paper with loose and rough texture is more prone to curling, while paper with tight and smooth texture is relatively difficult to curl.

2、 Production process and materials

Shrinkage characteristics of BOPP film:

BOPP film undergoes shrinkage when subjected to composite heating, due to the freezing of its molecular chain segments after stretching orientation. When reheated, it tends to recover its unstretched size. This shrinkage characteristic can cause the film to undergo thermal shrinkage in both longitudinal and transverse directions, leading to paper curling.

Coatings and additives:

The quality and formula of the coating, as well as the use of additives, may all affect the paper's resistance to curling. The treatment method of the coating surface and the type and amount of additives may have an impact on the curling degree of the paper.

3、 Printing conditions and settings

Printing temperature and pressure:

During the printing process, excessive temperature and pressure may cause uneven heating of the paper, leading to curling.

Printing speed and drying conditions:

Printing speed too fast or insufficient drying conditions may result in insufficient ink drying or penetration, thereby affecting the flatness of the paper.

4、 Storage and transportation

Storage conditions:

If paper is affected by unfavorable factors such as humidity, temperature, or light during storage, its performance may change, leading to curling.

type of shipping:

Squeezing, collision, and other factors during transportation may also cause paper to curl or deform.

In summary, the tendency of BOPP color synthetic paper to curl or deform during printing is the result of multiple factors working together. To reduce the occurrence of curling and deformation, efforts can be made to select paper, optimize production processes, adjust printing conditions, and improve storage and transportation. For example, selecting paper with tight and smooth texture, optimizing coating formula and additive usage, controlling printing temperature and pressure reasonably, and providing good storage and transportation conditions.