At present, there are three kinds of anti adhesion agents commonly used for mouth opening smoothing agent, oleic acid amide, erucic acid amide and silicon dioxide. There are also some differences in specific categories and usage methods. This paper mainly compares the differences between the three additives in the smooth opening and anti adhesion.

1. Brief introduction of the opening smoothing agent
(1) Oleic acid amide
Oleic acid amide, also known as oleamide; (Z) – 9-Octadecylic acid amide. Using it in polyethylene film can reduce the friction between the internal friction film and the conveying equipment during processing, and it is easy to demould, thus increasing the output and improving the surface gloss of the products. (Due to the low addition amount (0.1-0.15%) in the film, it must be added in the form of mixture or master batch in the processing plant to ensure a uniform smooth effect.)
Generally speaking, oleic acid amide migrates to the surface quickly, but the long-term friction coefficient of erucic acid amide is lower than that of oleic acid amide, and the thermal stability of erucic acid amide is better than that of oleic acid amide.
(2) Erucic acid amide
Erucic acid amide is mainly used as a smoothing agent and anti adhesion agent for CPP, BOPP, LDPE, LLDPE, EVA, PVC, PVDF, PVDC, PU, metallocene polyethylene and other plastics, which can significantly reduce the dynamic and static friction coefficient of the product (film or sheet) surface, and improve the processability and packaging efficiency.

(3) Silica
Main purpose
1) Keep the high gloss of the film.
2) With high specific surface area and strong adhesion resistance, it is very suitable for use as an opening agent in film materials.
3) It has good dispersibility and can be evenly dispersed in the resin to make 10-25% anti adhesion master batch. It can be used for PP, PE and other film products.
2. Function of the Open mouth Smoothing Agent
The reason why the film is not easy to separate is that the vacuum tight state is formed between the films after the film is closed, so it is not easy to separate; The other is that there are a large number of exposed molecular chains on the surface of the film after the film is formed. After the two films are closed, the macromolecular chains are intertwined with each other, making it impossible to open. In fact, the reason for the difficulty of membrane opening is the coexistence of the two, and the latter is the main reason.
3. Performance difference of oleic acid amide, erucic acid amide and silicon dioxide
Smoothing agent: adding the smoothing ingredient into the film is like adding a layer of water between two glasses. You can easily slide two glasses, but it is difficult to separate them.
Opening agent: adding opening agent or opening masterbatch into the film is like roughening the surface between two glasses with sandpaper. You can easily separate the two glasses, but you can hardly slide them.
Opening masterbatch: the composition is silica (inorganic matter) no migration
Smooth masterbatch: component amide (organic matter) no migration.
Note: At present, the main function of adding the smoothing agent to the plastic film is to change the sliding property and anti viscosity of the film by significantly reducing the friction coefficient of the film.
(1) Oleic acid amide
The addition amount of oleic acid amide film is low (0.1-0.15%), which must be added in the form of mixture or master batch in the processing plant to ensure uniform smoothness. Oleic acid amide has a good opening effect on PE, and it can be separated quickly, and the requirements can be met with a very low addition amount. However, it also has a fatal weakness, such as strong taste and fast separation, which affects corona and printing. It also has strict requirements for temperature. The amount of oleic acid amide is different in summer and winter. In addition, it is also added to the surface layer and core layer with great care.
(2) Erucic acid amide
Erucic acid has strong smoothness, less precipitation, high temperature resistance, and is not easy to turn yellow. It has obvious advantages over oleic acid.

For example, as a new packaging material, BOPP has a packaging speed of up to 500~800 packets per minute, and its friction factor must be ≤ 0.2. Only by adding erucic acid amide (about 0.12%) can we obtain the static and dynamic friction factors.
In addition to being used alone, for example, the PP blown film with high requirements for smoothness is mixed with erucic acid amide and oleic acid amide in the actual production process to achieve the best effect.
(3) SiO2 anti adhesion agent
SiO2 anti adhesion agent (opening agent) can be evenly dispersed in the film, forming many fine and hard protrusions on the film surface, thus reducing the contact area between the films, achieving the purpose of reducing the film surface friction coefficient, making the film easy to open. At the same time, the existence of these protrusions makes it easy for external air to enter between the two films, avoiding the formation of vacuum between the two films, So as to prevent film adhesion. Reply to “Shuangshuai” for more articles
4. How to select additives?
In the open and smooth masterbatch, the selection of amide and silica is very important to the performance of masterbatch
Because the quality of amides is uneven, and the additives with poor quality will make the masterbatch taste big and there are black spots on the membrane when it comes out of the membrane. These are caused by excessive impurities in animal oil. Therefore, in the process of selection and use, it should be determined according to the performance and use of amide.
The selection of silicon dioxide is more important. The particle size, specific surface area, water content, surface treatment, etc. have an important impact on the production of master batch and the process of film removal.
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