Preparation method for high-transparence bright inflatable packing film special for baking foods

Abstract

The invention discloses a preparation method for a high-transparence bright inflatable packing film special for baking foods. A polypropylene printing film and a polypropylene heat sealing film are used for forming the two-layer structure composite film through a water-soluble polyacrylate adhesive and a dry-type compound process. The preparation method is characterized in that the polypropylene printing film is a bi-oriented polypropylene film (BOPP film) or a BOPP film containing functional coating; the polypropylene heat sealing film is an allyl elastomer modified cast polypropylene film (CPP film); the water-soluble polyacrylate adhesive is used for fitting the polypropylene printing film and the polypropylene heat sealing film through the dry-type compound process. The high-transparence purpose of the composite film materials is achieved, the inflatable, pressing-resistant packing process requirement is met, meanwhile, no solvent is left, and the high-transparence bright inflatable packing film is very suitable for automatic inflating packing of the baking foods.

Description

technical field [0001] This patent relates to a composite film for food packaging, especially a preparation method for a high-transparency air-filled packaging film for baked food. Background technique [0002] Due to the special fresh-keeping and moisture-proof requirements of baked foods such as biscuits, bread, and cakes, the material structure of the packaging materials is usually a two-layer composite film based on polypropylene, such as biaxially oriented polypropylene / cast polypropylene (BOPP / CPP) or biaxially oriented polypropylene / cast polypropylene (KOPP / CPP) coated with polyvinylidene chloride. The composite film preparation process mostly uses two-component polyurethane adhesives, but there are still two major technical bottlenecks: (1) The transparency and brightness of the composite film are poor, the general haze is ≥ 3%, and the reflectance is ≤ 80%. As an inflatable transparent packaging film, the overall shelf effect is poor, which is not conducive to cons...

AI Technical Summary

Problems solved by technology

[0002] Due to the special fresh-keeping and moisture-proof requirements of baked foods such as biscuits, bread, and cakes, the material structure of the packaging materials is usually a two-layer composite film based on polypropylene, such as biaxially oriented polypropylene / cast polypropylene (BOPP / CPP) or biaxially oriented polypropylene / cast polypropylene (KOPP / CPP) coated with polyvinylidene chloride. The composite film preparation process mostly uses two-component polyurethane adhesives, but there are still two major technical bottlenecks: (1) The transparency and brightness of the composite film are poor, the general haze is ≥ 3%, and the reflectance is ≤ 80%. As an inflatable transparent packaging film, the overall shelf effect is poor, which is not conducive to consumers observing the product through the packaging film; (2) Adhesives lead to low peel strength between films, generally ≤0.6N / 15mm, low peel strength causes the risk of inflated bag breakage, often manifested in pressure-resistant, explosive bags, which cannot meet the requirements of inflatable protection products

(3) Solvent-based polyurethane adhesives inevitably have solvent residues, which are easy to cause secondary pollution to food and produce peculiar smell, which is not conducive to food safety

[0003] Chinese invention patent "PVDC-polyolefin co-extrusion thermoforming high barrier composite packaging material" (patent number: 200610040449.6) discloses a combination of upper and lower film packaging, the upper film: BOPP / PE-TIE-PVDC-TIE- PP-PE is formed by multi-layer cast or blown film co-extrusion and solvent-free dry composite molding; lower film: PP-TIE-PVDC-TIE-PE is formed by multi-layer cast or blown film co-extrusion; Solved the technical problem that it is difficult to effectively combine PVDC and polyolefin materials under co-extrusion conditions due to the large difference in thermal sensitivity and the stress balance between crystalline resin and non-crystalline resin.

Images