What factors affect the gloss of BOPP synthetic paper?

The factors that affect the gloss of BOPP (biaxially stretched polypropylene) synthetic paper can mainly be summarized as follows:

First, factors in the production process

1. Formulations and additives:

The type and amount of additives such as hydrogenated petroleum resin, adhesive, electrostatic agent and smoothing agent will directly affect the gloss of BOPP synthetic paper. The migration and distribution of these additives in the film will change the surface morphology of the film, thus affecting its reflection and refraction characteristics of light.

The inorganic anti-adhesion agents and some migratory non-ionic surfactant-based antistatic agents in the formulation may have a negative effect on gloss, because they have poor compatibility with PP (polypropylene) and tend to form an aggregation layer on the surface of the film, reducing gloss.

2. Processing technology:

Processing temperature and production line speed are also important factors affecting gloss. Too high processing temperature or too fast production line speed may lead to incomplete crystallization within the film, which affects its surface smoothness and gloss.

The stretching ratio and the stretching rate in both vertical and horizontal directions in the drawing process also affect the molecular orientation and crystalline structure of the film, which in turn affects its gloss.

Second, factors in the stored process

1. Storage time and conditions:

With the extension of storage time, the gloss of BOPP synthetic paper has a trend of decreasing gradually. This is mainly due to the migration of core layer additives to the surface, forming an aggregation layer and changing the surface morphology of the film.

Storage conditions such as temperature and humidity also affect the migration rate of additives and the recrystallization process of the film, which has an impact on gloss.

Third, the nature of the material itself

1. Properties of PP (polypropylene) raw materials:

The properties of PP material, such as molecular weight distribution and crystallinity, will affect the tensile properties and crystal structure of BOPP synthetic paper, and then affect its gloss.

2. Thickness and structure of the film:

The more uniform the thickness of the film and the denser the structure, the better its gloss is usually. Conversely, if the film thickness is uneven or defective, its gloss may be affected.

Fourth, post-treatment process

Surface coating treatment: such as plasma treatment can improve the printability and adhesion of BOPP synthetic paper, and may also have a certain impact on its gloss. The type and amount of coating material needed to be carefully controlled to balance gloss and other properties.

In summary, the factors that affect the gloss of BOPP synthetic paper are many, including the formula and additives in the production process, the processing technology, and the time and conditions in the storage process. In order to obtain stable and excellent gloss performance, it is necessary to strictly control the parameters and conditions during production, storage and post-processing.