Study on Application of BOPP Film Anti-adhesion Agent

Abstract: Anti-blocking agent is the most commonly used additive in the production of BOPP (biaxially oriented polypropylene) film, but it is also the most likely to cause problems with the film. This article summarizes the characteristics of different types of anti-tacking agents and their effects on the properties of the films, and describes the methods for selecting anti-tacking agents and addition amounts and the handling of common problems.

Keywords: anti-adhesive; BOPP; film

Foreword:

In the production of BOPP film, according to the application requirements of the film, it is usually necessary to add additives for different functional purposes, such as slip agents, antistatic agents, anti-adhering agents, reinforcing agents, matting agents, pearlizing agents, brighteners, etc. However, no matter which type of BOPP film is produced, an anti-sticking agent must be added to the surface of the film, otherwise the film may not be used. In this sense, anti-sticking agent is the most important additive in the production of BOPP film, and it is also the most easily added additive that causes film problems. Therefore, the type and amount of anti-adhesive agent must be reasonably selected in order to achieve control. The purpose of product quality. In particular, in recent years, China’s BOPP industry has achieved rapid development and has become the fastest growing region in the world for BOPP. New manufacturers are entering this field, but due to poor consideration in the formulation of BOPP film technology. Therefore, it is impossible to reach the required product quality, and more serious is due to the improper use of anti-adhesive agents, resulting in the product can not be used, resulting in greater economic losses to the enterprise. This article introduced different types of anti-adherent agents based on production experience. The characteristics, uses, and their effects on the properties of the film, discussed how to control the performance of the film by selecting the anti-adhesive agent and the amount of the anti-adhesive agent, and summarized the common problems and solutions of the anti-adhesive in use.

1 BOPP films mechanism of anti-tack agent, the type and characteristics of

In the production of BOPP film, either the semi-finished product or the finished product must be wound on the winding core. Since the thin film is thin and the winding is tight, this may cause the possibility of blocking between the films. When a certain amount of an anti-sticking agent that is incompatible with polypropylene resin is added to the surface of the film (the anti-adhering agent is usually added on the surface of the film), since the particle size is 3 to 5 μm, the surface layer thickness of the film is generally 1 μm. The anti-sticking agent, which is exposed on the surface, forms an air barrier layer between the films and thus acts as an anti-sticking effect.

As an anti-sticking agent for BOPP film, it must have good anti-adhesiveness, dispersibility, non-toxicity and similar refractive index to polypropylene resin. At present, the anti-sticking agents on the BOPP market at home and abroad have two major categories: inorganic and organic. The main inorganic anti-blocking agents are synthetic silica, synthetic china clay, glass beads, and calcium carbonate. This type of anti-adhesive agent is irregular or round in shape and has a particle size of about 3 to 5 μm. It is transparent and sensitive to moisture. The hardness is moderate except that silica is hard and the anti-adhesive agent has a high The surface area contributes to the absorption of other additives. In this regard, the silica anti-blocking agent is slightly more pronounced.

Organic anti-blocking agents are new varieties developed in recent years. Among them, the more typical products are silicone polymers, such as polysiloxane polymers. These anti-blocking agents have both anti-sticking and slipping properties. 4um, round, transparent, softening temperature or lower melting point, insensitive to moisture and other additives.

According to the raw materials used, BOPP anti-adhesive agent can be pre-formulated with polypropylene homopolymer, polypropylene copolymer and even slip agent to make masterbatch, the concentration is generally 2% to 15%, and the dispersibility is better when the concentration is low. In addition, some polypropylene copolymers are often added with anti-adhesives during production, which have better dispersibility and lower costs. However, raw material manufacturers have low accuracy in controlling the concentration of additives, and sometimes the performance of the products is quite different. On the other hand, it is not convenient. When used by BOPP manufacturers, the manufacturers should use the anti-adhesive additive form correctly according to the formulation requirements and product characteristics.

2 in a different type and amount of anti-tack properties of the films

2.1 Effect of the film on the anti-adhesive properties

In the above BOPP commonly used anti-sticking agent, there are some differences in the anti-adhesion properties, such as the production of 25 um aluminizing heat sealing film, the core layer and the aluminized surface without additives, the other surface plus 3000 ppm anti-adhesive agent At the time, the film produced by the following anti-tacking agent was measured for its corresponding blocking strength as shown in Fig. 1:

The greater the adhesion strength of the film, the worse the anti-adhesion performance of the corresponding film. From the above comparison, the anti-sticking effect of synthetic silica is best. It is currently the most widely used BOPP anti-adhesive at home and abroad. The anti-sticking effect of calcium carbonate is the worst, but because of its low cost, it can be considered when adding more amount of non-transparent products to use. At this time, it has both anti-sticking and filler functions. Others Several kinds of anti-adhesives have their own characteristics, and their anti-sticking effects have certain differences. Therefore, when choosing different types of anti-adhesives, the amount of anti-adhesion agent should be adjusted to ensure the anti-adhesive properties of the film.

(to be continued)