Degradable barrier composite film for packaging

Abstract

The invention relates to the field of packaging materials, and discloses a degradable barrier composite film for packaging. The degradable barrier composite film comprises a degradable layer and a barrier layer which are tightly attached. According to the invention, the thicknesses of the degradable layer and the barrier layer are strictly controlled, and the barrier film which is tightly combinedis fragmented by virtue of volume change and internal stress of the degradable layer in the degradation process, so that the degradability of the barrier film is realized; and the auxiliary agent capable of remarkably improving the melt fluidity is added into the degradable material, or the melt fluidity of the degradable polymer is improved through molecular structure design of the degradable polymer, and after the melt fluidity of the degradable material is close to that of the barrier material, the difficulty of preparing the composite film through a stretching process is greatly reduced.

Description

technical field [0001] The invention relates to the field of packaging materials, in particular to a degradable barrier composite film for packaging. Background technique [0002] High-barrier film materials are widely used in food, pharmaceutical, chemical and other product packaging, electronic device packaging and other fields due to their excellent barrier properties to gas, oil, moisture, etc., and good mechanical properties, especially in food The packaging of medicines, medicines and chemicals can significantly improve the shelf life of food and medicines or the storage period of chemicals. In the current society, people's awareness of environmental protection is increasing day by day. In many fields, people use degradable materials to replace traditional non-degradable or refractory materials. [0003] Among the high barrier film materials, the most widely used raw materials are polyvinylidene chloride, ethylene / vinyl alcohol copolymer, etc. As we all know, the abo...

AI Technical Summary

Problems solved by technology

However, in order to ensure the barrier effect, the thickness of the current barrier layer is relatively thick

And although the degradable material layer can degrade, the thicker barrier layer still cannot degrade

On the other hand, the fluidity of degradable materials and traditional high-barrier film materials is quite different (for example, the fluidity of degradable polylactic acid materials is 0.8 at a temperature of 190 °C and a load of 2.16 kg according to GB / T 3682-2000. g / 10min while the melt fluidity of ethylene-vinyl alcohol copolymer (EVOH) material is 3.2g / 10min under the same conditions, and the melt fluidity of polyvinylidene chloride (PVDC) material is 1.9g under the same conditions / 10min,), the difference in fluidity of the two layers of materials makes it difficult to stretch and compound the two materials at the same time during production, the extrusion of different material layers is uneven, and the distribution of each layer of the final product is uneven, so that The barrier and mechanical properties of the product cannot meet the relevant requirements of the barrier film. Therefore, such composite film products have not been produced by the stretching process so far.

[0005] In order to solve the technical problem that the above two materials cannot be produced by the stretching process, some people try to spray high barrier materials on the surface of the degradable film, but because the spraying process is compared with the stretching process, the density of the final formed film layer is much worse. Many, therefore, in practical applications can not meet the requirements of high barrier film