Aluminum-plastic composite film with excellent heat sealability and tearing resistance

Abstract

The invention provides an aluminum-plastic composite film with excellent heat sealability and tearing resistance. The aluminum-plastic composite film comprises a casting polypropylene film layer, an aluminum foil layer and a biaxially oriented polyamide film layer, which are glued together from inside to outside in sequence, wherein the orientation degree fav of the casting polypropylene film layer in a machine direction is 0.05-0.5. A polypropylene resin raw material used for manufacturing the casting polypropylene film layer meets the following features at the same time: the weight-average molecular weight is between 150,000-700,000, the molecular weight distribution index is between 1-15, the degree of isotacticity is 90.0-99.9%, the content of a xylene soluble substance is 10.0-0.1wt%, and the melt flow index is 1-10 g/10 min; (2) the melting peak width is 10-50 DEG C, and the relative crystallinity is 20-45%; and (3) the average crystal plate thickness is between 8-28 nm. The aluminum-plastic composite film provided by the invention can be heat-sealed and obtain high hot-sealing strength within a broad temperature range and has more excellent tearing resistance, and a user can use the aluminum-plastic composite film in harsh environment for a long time without fear of damaging a heat-sealing layer.

Description

technical field [0001] The invention relates to packaging materials, in particular to an aluminum-plastic composite film with good heat-sealing performance and tear resistance. Background technique [0002] Lithium-ion secondary batteries are widely used as power sources for notebook computers, video cameras, mobile phones, electric vehicles, and the like. As this lithium ion secondary battery, the structure around the battery body is protected by the case, which is called a case packaging material. Lithium-ion soft-pack batteries need to be heat-sealed and packaged with aluminum-plastic composite film. Packaging is an indispensable and important part of it. Lithium batteries cannot exist independently without packaging. The service life of packaging is the same as that of lithium batteries. Service life has the same life cycle. Aluminum-plastic composite film packaging materials must have good heat-sealing performance, be able to quickly heat-seal in a wide temperature ra...

AI Technical Summary

Problems solved by technology

[0005] At present, there are packaging materials that are sequentially bonded and integrated by a stretched polyamide layer, an aluminum foil layer, and a polypropylene layer, wherein the polypropylene film layer is a heat-sealing layer. However, the prior art does not realize that the polypropylene layer The molecular structure and crystallization of the polypropylene resin raw material used, as well as the degree of orientation in the machine direction after film formation, have a decisive influence on the heat-sealing performance and tear resistance of the aluminum-plastic composite film, so it is difficult to obtain a good heat-sealing performance. Aluminum-plastic composite film with tear resistance and tear resistance cannot well meet its application in packaging batteries

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