Clamshell Blog

Flexible packaging manufacturer in the laminating process, sometimes encounter such a phenomenon: the use of ordinary polyurethane adhesive compound polyethylene film, when the plane had just re-good film, the peel strength can meet the requirement into the drying room, after curing strength but a significant decline, or take a long time, easy to open, broken bags. Film manufacturers are often considered to be plastic problem, in fact the reasons for this phenomenon, under normal circumstances is due to precipitation of the film caused by smooth auxiliary agent.

We know that the film in the production process, mostly by adding a number of heat stabilizer, antioxidant, anti-viscosity, open Smoothness agent additives, so as to prevent adhesion and easy processing. Additive because it is to be added, rather than grafted on PE molecules, and thin-film processing is getting better, with the passage of time and temperature changes, auxiliary membrane lining the surface from leaking outward migration. Careful observation will be found to be a thin layer of powder or waxy substance, hand rub can also be erased. The longer the more the amount of migration, thereby reducing bond strength.

PE film additives on the adhesive strength of composite is generally the greatest impact smoothness agents, such as erucic acid amide, oleic acid amide and so on. Under normal circumstances, the thicker the film per unit area with more smooth agent. Practice shows that when the polyethylene film thickness of more than 60μm, the phenomenon of additive precipitation will increase significantly. This is because the same surface area, and as film thickness increases, its internal measure of additives contained in the corresponding growth. Additive content in the film, after more than a certain amount, will affect the performance of Film. Films smooth agent content (ppm) × film thickness (μm) = 2200 ~ 26,000 between, coupled with a reasonable production process, can make the composite products has some of the peel strength, but also can make composite membrane with smooth enough sex. When smooth agent concentration (ppm) × film thickness (μm) of more than 26,000 more, using ordinary polyurethane laminating adhesives may occur due to smooth peel strength doses caused a substantial decline in precipitation of the problem. In the same amount of glue down Shuang agent content was high, the product of more than 26,000 of the film peel strength dropped significantly. Of course, a large quantity of peel strength glue will be big, but it will increase costs. If the use of resistant plastic additives, may not be affected. Because the gel contains an inclusive smooth agent composition, to avoid the impact of smooth agent.

Polyethylene film as the sealing flexible packaging materials, raw material content of the smooth agent how many pairs of composite peel strength, open nature, smooth, and seal strength of crucial, if overlooked this point, it will produce high-quality accident losses. Therefore, the flexible packaging manufacturers in the selection of polyethylene film, it must pay attention to.

One of polyethylene film to understand the content of smoothness agents, and some manufacturers may take the initiative to offer to you, and some manufacturers do not provide as a technical secrets. Thus, when an ordinary-type polyurethane laminating will definitely have to be careful, do first a small test, or simply use the next-resistant rubber additives, avoid excessive smooth agent concentration caused by quality problems.

Second, it should detect the surface tension of polyethylene film, because film if Smoothness agent precipitation, surface tension would not reach laminating requirements that need to re-spark processing. The wax precipitation in the spark out of the high temperatures will be volatile, so that will not affect the composite strength.

Third, select the appropriate adhesive, because the high content of smooth thin-film agent, only these special adhesive to overcome the smoothness of the precipitation agent, to avoid the precipitation caused by quality problems.

Fourth, to understand the aging temperature settings. Should generally be taken as far as possible under low temperature aging, in order to avoid high doses increased precipitation of smoothness. The plane of the composite membrane as soon as possible into the ripening room, at 40 ℃ ~ 50 ℃ under the conditions of heated composite membrane, so that has not yet cured adhesive melt leveling to eliminate the smaller bubbles and white spots, a continuous 48 hours after curing will be able to reach a satisfactory bonding strength.