We must be familiar with the film rolling. The film can be directly turned into a packaging bag after the automatic packaging machine. Some days ago, some customers reported that the nylon film roll broke in the process of use. Stop the machine to check: the end face of the BOPA film is clean, but there are some small resin like transparent dry adhesive attached to the end face of the roll film, resulting in the film breaking.

In the production process of nylon film, there is no chance to catch up with resin or adhesive, so where does the dry adhesive come from? It is suggested that both parties should find out the causes again.

1、 There are several reasons for film breakage at the end face of film rolling
BOPA film belongs to biaxially oriented film, and this type of film has a characteristic, that is, after biaxially stretching, the initiation tear strength of the film is very large, but the secondary tear strength is greatly reduced. As long as the slitting knife mark, notch or other film surface defect fault is left, it is easy to tear under printing or composite tension. Generally, the transverse stretching force of oriented plastic film is small. Once it meets small gap, knife mark and scratch, it is easy to break the film under the action of external force. The reasons for film breaking of directional plastic printing film roll are as follows:
1. Serious fault stacking. The film slips or the width of film changes in the winding process, and some film faults appear on the end face of the film roll. And this phenomenon is related to the cutting speed, and it is easy to see from the surface of the end face. Large staggered layer is easy to produce transverse tension, not disorderly produce membrane rupture.
2. End face injury. Such as scratches, bumps, slitting knife is not sharp, resulting in zigzag edge stagger or other surface faults, etc., the film will be broken under the action of external tension.
3. Due to the quality of the film itself, the tensile and fracture forces are too small; or a large number of additives on the film surface float up, the film surface is particularly rough, the friction coefficient is too large, and the tensile force is unbalanced, or there are large crystal point plasticizers and other foreign matters on the film surface.
4. Equipment reason or production process reason.
2、 Case reason:
Edge sticking and film breaking rarely occur in white film, because there is no chance of meeting adhesive in film production and printing process. The so-called edge sticking is a phenomenon that the plastic film is heated and dried by the drying channel after being coated and glued, and then rolled up after being extruded by a hot pressing steel roller, and the two sides of the winding product are adhered together. After the edge sticking fault occurs in the winding product, the film is tightly bonded at both ends of the coil, which will cause the membrane separation problem of the finished product. Especially in the use of two-component two-liquid reactive adhesive, the most easy to rise, severe will lead to composite products were broken, tensile deformation, so that the product scrap.
The film manufacturer and the film user found no practical clues from the aspects of production process, on-site record and inventory of goods in the same period. They only found the broken film model in the slitting record, and there was a record of blade change on the same day, while there was no adverse feedback on the film roll produced before and after the blade replacement. Later, there was a feedback from another manufacturer that the film was broken due to adhesion during printing. After searching, two pieces of broken roll film in the unified day of the unified station, only the slitting shift is different.
Therefore, the range of film breaking and edge sticking can be reduced to the film making and cutting process to find out the causes.
If there is no real sample left, only a small amount of transparent sticky material is sent for testing. The result shows that it is nylon particle material. After analysis, if the crystal point will not appear at the same time in the unified slitting station, unless there are defects in the melt extrusion die head. No large crystal point or plasticizer was found in the same position of the film. During the discussion and analysis with the slitting staff, an old employee provided a very useful clue, that is, sometimes when the slitting is off the shelf, sometimes the end face is very hot and hot. If the surface of the film will be hot, the film will be soft. If there is external force at this time, the edge adhesion of the film will be generated, but whether the film will be broken depends on the degree of sticking and use. The residual heat of the membrane will not be too hot to find the source of fever?
There is a concave keyway on the slitting machine to control the cutting width and place the slitting knife. There is a block partition every 5 mm. When changing the blade, if the blade is installed close to the baffle block, the rapid running friction of the slitting film will lead to the accumulation of heat for a long time, resulting in the softening of the interlaminar membrane at the cutting end face, and the adhesion state of the end face is formed by the action of external force, resulting in edge sticking and film breaking. In fact, the customer's feedback about the broken film was caused by this reason, and the adhesive edge was formed by several layers of nylon film. It is not easy to find out that this kind of end face sticking is not easy to be found. Firstly, the blade is not installed in the middle of the concave keyway for heat dissipation, so as to avoid friction between the blade and the groove wall and generate a large amount of heat source, which makes the film edge soft. More importantly, after the film is rolled off the shelf, the film surface is immediately packed and compressed when the film surface is still very hot (for example, the film is pressed by the hot edge, so it is generated The phenomenon of edge sticking at the end of white film roll. The probability of this type of failure is very small, but it still occurs, so it is put forward for reference.
Dongguan Beite packaging materials Co., Ltd. is a large-scale company specializing in the production of food grade composite packaging. It is a professional manufacturer of composite packaging bags. It uses new equipment to produce packaging bags and roll films, providing comprehensive, environmental protection and safety packaging services for the market. The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries. We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.