What is the PE laminating film? The way of PE film laminating.
During the manufacturing process of PE film, the raw materials are extruded onto another film or different kinds of films that have been made are laminated together to form a multi-layer film. This product is called a PE laminating film. It is usually a multi-layer structure that combines a substrate and a polyethylene film (single layer or co-extruded) using an adhesive.
Extrusion laminating methods: wet laminating; solvent-based dry laminating; solvent-free dry laminating.
The problems and solutions will occur in the PE film laminating process?
1. The composite is not strong: the composite strength is very low , which can not meet the customer’s requirements at all, the product is scrapped..
1) The surface tension of dry laminating PE film is low, usually the tension must reach 38dyn/cm or more before it can be used. If the surface tension value of the PE film is lower than 38dyn/cm, it may cause the phenomenon of low composite strength.
2) When PE is polymerized or PE film is formed, a certain amount of additives is generally added according to its use. After the PE film is placed for a short time, the additives will migrate to the surface of the PE film to form a thin dense layer. This dense layer blocks the bonding between the adhesive and the surface of the PE film, resulting in the adhesive being unable to contact the PE molecules, and the composite initial adhesion is very low. With the increase of curing time, the composite strength does not change much, and the composite strength is always Keep it low or zero.
3) The PE film is contaminated during the production process. After being laminated, it does not cross-link with the binder molecules, resulting in zero local compound strength.
2. The white spots on the laminating film.
PE milky white film is all added with a certain amount of white additive. Due to the different quality of color additive, the particle size is different, and the hardness is also different, resulting in different quality of the milky white film produced after laminating, and different surface brightness. If the surface of the milky white film feels rough and has pitting from the side, most of the products compounded with such a film will have white spots.
3. The finished product becomes brittle after laminating.
The automatic packaging machine for the laminating product does not run smoothly, or the bag made is difficult to open. Dry laminating generally uses two-component reactive adhesives, which must be cured at a high temperature after laminating to achieve the highest compound strength. The slip agent in the PE film will change due to the change of curing temperature. At a certain temperature, the slip agent will chemically change and lose its slip effect. The higher the temperature, the greater the change and the loss of the slip agent. The larger the amount, the final product will become brittle and cannot be used.
4. Poor heat sealing
After the compound enters the last process or enters the hands of the customer, sometimes the local heat-sealing temperature is too high, the heat-sealing is not good, etc., which cannot be saved in serious cases. The reasons for this result include corona breakdown, high slip agent content, and excessive addition of recycled materials.
Therefore, in order to avoid the quality problems caused by the PE laminating film, the placement of the PE film should generally not exceed 3 months, especially in the rainy season, and more attention should be paid to the ventilation and ventilation of the storage. Before laminating, check the cleanliness, surface tension, etc. of the PE film. The curing temperature is strictly controlled during the production process. When reusing, in addition to the roll-by-roll inspection, it is also necessary to comprehensively consider whether to continue using the compound product according to the purpose of the composite product, so as not to cause loss.
