Heat-sealed bagging is widely used in packaging for daily chemical products, food, and pharmaceuticals. During product filling, the heat-sealed seams of the bags are prone to leakage, and during actual use, damage often occurs at these same heat-sealed areas. Therefore, by selecting an appropriate… Heat-seal film And by optimizing heat-sealing parameters, you can reduce the scrap rate on the production line and effectively enhance the overall barrier performance of the packaging. Now, let’s take a closer look. Heat-seal film Its characteristics, then!

Currently commonly used Heat-seal film It is made of polyethylene film or polypropylene film. PP film used as a heat-seal layer is primarily a copolymer of propylene and ethylene, offering excellent elongation, tensile strength, and heat-seal strength; however, its high heat-sealing temperature results in significant electrical energy loss in the sealing equipment. When PE film serves as the heat-seal layer, it requires a lower sealing temperature, and its tensile and heat-seal strengths are inferior to those of PP film. Nevertheless, it can meet the requirements of many packaging applications, making PE film the preferred choice for heat-seal films. Currently available PE films for heat-sealing include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene; among these, low-density polyethylene and linear low-density polyethylene are predominantly used in composite heat-seal layers.

In the prior art, the overall strength of PE film is typically enhanced by increasing its thickness; for example, a 120‑µm‑thick PE film can exhibit good stiffness and tensile strength. However, thicker PE films are more difficult to handle during packaging and reduce packaging speed. Bonding PE film to other polyolefins with superior mechanical properties can improve its strength. For instance, when PE film is laminated with a PP film that offers high transparency, excellent melt flow, excellent barrier properties, and high elongation, it enables sealing at lower temperatures, higher sealing speeds, and enhanced seal strength. Nevertheless, PE and PP have poor compatibility, so a polyolefin elastomer is usually added as an adhesion promoter. POE, on the other hand, exhibits inferior mechanical performance; therefore, using POE to bond PP film to PE film results in… Heat-seal film Delamination may occur during the heat-sealing process; the heat-seal layer exhibits high tensile strength but low heat-seal strength.

Heat-seal film Characteristics:

1. The heat-seal film comprises a surface layer and a second surface layer. The surface layer contains an ethylene homopolymer or an ethylene–C3–C20 olefin copolymer with a CDBI of at least 50 wt% and an Mw/Mn ratio of 3 or less; the second surface layer consists of an acrylic homopolymer or a copolymer of acrylic with one or more comonomers, wherein the comonomer content does not exceed 50 wt%. When this heat-seal film is directly laminated onto polypropylene using metallocene‑polyethylene, raw material costs can be reduced; however, the resulting heat-seal film exhibits a high sealing temperature and low seal strength.

2. Heat-seal film Its characteristic feature is that, by co-extruding polyethylene, a metallocene‑based ethylene–propylene copolymer, and polypropylene, a hot‑melt adhesive tube is formed, comprising sequentially an outer polyethylene layer, a metallocene‑based polypropylene layer, and a polypropylene layer. This tube is then blow‑molded into a film and cooled. Subsequently, the outer surface of the cooled, set film undergoes coronaviricide treatment, yielding a heat‑sealable film. The present invention provides a heat‑sealable film having continuous layers of polyethylene, a metallocene‑based polypropylene, and polypropylene, wherein the metallocene‑based polypropylene layer contains 25 wt% of the metallocene‑based ethylene–propylene copolymer. Furthermore, the invention employs the following process: co‑extruding polyethylene, a metallocene‑based ethylene–propylene copolymer, and polypropylene to form a hot‑melt adhesive tube consisting of sequentially contacting polyethylene, metallocene‑based polypropylene, and polypropylene layers; blow‑molding this tube into a film and cooling it; and finally subjecting the outer surface of the cooled, set film to coronaviricide treatment, thereby producing a heat‑sealable film. The heat‑sealable film provided by this invention is maintained at a relatively thin thickness, enabling high‑performance sealing while reducing packaging complexity and increasing packaging speed.

The above is what has been introduced. Heat-seal film Its features—please feel free to contact us if you’d like to learn more!