In order to obtain highly viscous PE Self adhesive film, it is necessary not only to strictly control the formulation standards, but also to strictly follow the prescribed process. For example, the stretch-wound film can be produced by a blow molding method. In this case, HOLD60 pellets with a weight ratio of 8% need to be added to 92% of the polyethylene, and mixed in the mixture for use.
In the actual production of PE self adhesive film, the first basic requirement we need to follow is to choose the appropriate base resin. Note that the resin should not contain any opener and slip agent because the presence of such additives can damage the film's tack. Recycled materials should not be used when the masterbatch is first tested. Moreover, the density of the base resin should be as low as possible. Secondly, it should be clear that the higher the temperature of the machine head, the better the blow molding. In addition, the temperature of the cooling air will also directly affect the viscosity of the protective film.
In general, in the molding process, the lower the cooling air temperature, the better the viscosity of the obtained PE self adhesive film, and the viscosity increases as the standing time is lengthened. For films of the same thickness, the greater the blow ratio, the better the tack. The bubble blowing ratio of the 25u thick film is recommended to be 3:1. Alternatively, a casting method can be used to produce a stretch-wound film. At this time, HOLD60 pellets having a weight ratio of 4% need to be added to 96% of LLDPE, and mixed in a mixer to be used.
For the time being, in the production of PE self adhesive film, it is often important to use a raw material having excellent elongation and tensile strength, and the resin cannot contain any slipping agent or opening agent. Because the presence of such additives can damage the viscosity of the film. Recycled materials cannot be used for the first trial of this masterbatch. The cast film is usually a multilayer composite film processed by 2-3 extruders. The cast film has a lower crystallinity and more amorphous regions than the blown film, so HOLD60 only needs to be added to the surface layer (inner and outer layers). The multilayer cast film can also be made into a single-sided bond by simply adding 3-4% of HOLD60 to the inner layer (cooling roll contact layer).
In addition to the above requirements, no matter which production process is used, the high-viscosity PE should be ensured to be flat before the winding, and the tension of the winding roller should not make the film roll too tight or too loose, otherwise the film will be stored for a period of time. Later, unevenness will occur at the end of the film roll and at the sleeve. Usually the viscosity of the film will be partially exhibited during the winding process, but the maximum effect is generally expressed within 72 hours after forming.
It should be noted that when the finished high-viscosity PE is self adhesive film, it is preferable to keep the ambient temperature within the range of 7 to 35 degrees. If we can meet these requirements at the same time, we can obtain high-viscosity, highly transparent, highly viscous PE self adhesive film.