Although the overall performance of the pre-coating film coating method is better than that of the instant coating film coating method, in view of the current status of the domestic automatic laminating machine, the vast majority of domestic enterprises are still generally using the instant coating film coating process. The water content changes with the relative humidity of the air. Prints that are sensitive to humidity will generate internal stress due to dimensional changes. For example, the longitudinal expansion and contraction rate of printed matter is 0.5%, and the longitudinal thermal shrinkage of BOPP film is 4%. If the printed matter absorbs too much water and stretches, internal stress will be caused between the heating and shrinkage of the film, which will cause the laminated product to curl, wrinkle, and stick. The main reasons for insecurity can be summarized as follows.
First, the pre-coating film coating technology started relatively late in China.
Second, the production of pre-coating film has high technical content, complicated process, and large equipment investment. General enterprises cannot afford to invest in pre-coating film production lines.
Third, due to the surplus of labor resources and low labor costs in my country, material costs account for a large proportion of the overall cost of the film coating process. The cost of pre-coating film is higher than that of coating film, which will inevitably affect its application.
On the one hand, in terms of strength, the UV coating process has little contribution to enhancing the strength of the printed matter, while the laminating process can increase the strength of the printed matter several times. On the other hand, with the advancement of technology, further processing such as hot stamping and frosting after coating will make the post-processing process of printed matter more complicated. In today’s era when intellectual property protection is emphasized and businesses emphasize product anti-counterfeiting. Coating has more advantages than UV coating.

The laminating speed of the automatic laminating machine determines the melting time of the adhesive on the pre-coated film on the heating roller and the contact time between the film and the paper. The laminating speed is slow, the heating time of the adhesive on the BOPP film is relatively long, the pressing time of the film and paper is long, the bonding effect is good, but the production efficiency is low. The laminating speed is fast, the heating time of the adhesive on the BOPP film on the heating roller is short, the contact time between the film and the paper is short, and the bonding effect is poor. The production speed of domestic pre-coating film laminating equipment is generally controlled between 5 and 30m/min.