Polypropylene zipper for liquid packaging and preparation method thereof

Abstract

The invention discloses a polypropylene zipper for liquid packaging and a preparation method thereof. The polypropylene zipper is obtained by putting a polypropylene zipper material into a feeding cylinder of a high-speed zipper extruder, melting at high temperature, extruding through a mouth mold, and cooling and shaping. The polypropylene zipper material is prepared from the following components in parts by weight: 50 to 70 parts of polypropylene I, 30 to 50 parts of toughening elastomer, 2 to 10 parts of nucleating smooth master batch, 0.05 to 0.1 part of antioxidant and 0 to 0.1 part of composite light stabilizer, wherein the total amount of the polypropylene I and the toughening elastomer is 100 parts; and the nucleating smooth master batch comprises polypropylene II, inorganic silicon dioxide, a nucleating agent and a slipping agent. The waterproof effect of the PP zipper is achieved, the performance that PP is prone to embrittlement, not resistant to low-temperature freezing and resistant to high-temperature steaming and boiling is improved, and about 50% of production energy consumption of the zipper is reduced.

Description

technical field [0001] The invention relates to the field of zipper composite bags, in particular to a polypropylene zipper for liquid packaging and a preparation method thereof. Background technique [0002] The zipper composite bag is a product with a tight seal to prevent air from continuously entering the inner bag, and is easy and convenient to operate. The zipper materials used in commercial zipper composite bags are generally polyethylene, polypropylene and EVA (ethylene-vinyl acetate copolymer). Welding process is generally adopted, considering the welding performance of different materials, it is necessary to select the corresponding zipper material for matching according to the material of the composite bag. As for liquid packaging, because PE zipper and film have good thermal sealing property and softness, liquid sealing can already be realized through technical means, see patent application CN109575407A "a film zipper production formula and process". However, P...

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Problems solved by technology

[0004] 1) The PE material zipper can be waterproof, but it cannot be welded with the PP bag body;

[0005] 2) The PE zipper material can be welded with the PP bag after modification, but the smell produced by the PE material after irradiation cannot be avoided, and it cannot withstand high-temperature cooking, and it will be deformed after cooking;

[0006] 3) The transparency of the PE zipper material is poor, which cannot meet the requirements for the appearance of products with transparency requirements;

[0007] 4) PP material zippers can only be used for the packaging of some solid products due to their high hardness and insufficient elasticity;

[0009] 6) The PP zipper material has a large shrinkage rate, and the zipper skeleton is prone to shrinkage pits and is not full;

[0010] 7) PP zippers are usually prone to stretching due to the high heat-sealing temperature, and it is difficult to maintain the flatness of the heat-sealing part after sealing with the PP bag body, and the part sealed with the bag body is also prone to local delamination;

[0011] 8) PP zipper material is brittle, easy to break when bent, not resistant to low temperature, and cannot be frozen

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