High-barrier EVOH (ethylene vinyl alcohol) coextruded film

Abstract

The invention discloses a high-barrier EVOH (ethylene vinyl alcohol) coextruded film. The high-barrier EVOH coextruded film is a seven-layer composite film and is characterized by comprising a nylon layer, a first nylon / EVOH layer, a second nylon / EVOH layer, a third nylon / EVOH layer, a nylon / EVOH / MLLDPE (metallocene linear low-density polyethylene) layer, an EVOH / MLLDPE layer and an MLLDPE layer from the outer layer to the inner layer sequentially. The film has a good barrier effect, and a decomposition layer cannot be formed in a production process.

Description

technical field [0001] The invention discloses an EVOH high-barrier co-extrusion film and relates to the technical field of nanostructure materials. Background technique [0002] According to statistics, the loss of agricultural products and food due to the lack of high-barrier packaging materials in the world accounts for about 20%-30% of the total output; 20%-30% of the total output of fruits and vegetables in my country is also due to the barrier properties of packaging materials during transportation and storage. The loss caused by insufficient production amounted to 600 billion yuan. High-barrier packaging materials are widely used in precision mechanical parts, electronic parts, etc. to improve their service life. They are used in food, drug and other packaging to prevent the migration of harmful substances and prevent the oxidative damage of built-in materials. Therefore, the research on high barrier packaging materials is of great significance. [0003] At present, ...

AI Technical Summary

Problems solved by technology

At present, the commonly used method is to prepare high-barrier materials on the surface of plastic sheets. This production method often uses volatile organic solvents in the preparation process, which involves the preparation of substrates, composite film materials and other processes, and there are many processes. serious waste

[0004] At present, there are still some technical difficulties in blown film co-extrusion, such as the number of layers is not allowed to have more changes; the ratio of each layer of film is not allowed to fluctuate greatly; As the number increases, the outer diameter of the machine head increases, the residence time of the melt of the outer film in the machine head increases, and the material is in danger of decomposing; , for some resins with poor thermal stability, it is possible to form a decomposition layer, etc.

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