Rouleau de thermoformage PP/EVOHPE haute barrière pour barquettes de viande

1. PP/EVOHPE high barrier film

EVOH is a crystalline polymer with chain structure, which is a random copolymer of ethylene _ ethylene alcohol, so it integrates the good processing property of ethylene polymer and the high gas barrier property of ethylene alcohol polymer.

When ethylene monomer was added, the tensile strength and impact strength of EVOH decreased while the water resistance and processing performance were improved.The barrier of EVOH membrane can be increased by 2~3 times after bidirectional stretching.

In EVOH copolymer, EVOH with different properties can be obtained by changing the content of ethylene monomer and ethylene alcohol monomer.Among them, ethylene monomer provides water resistance and processability, while ethylene alcohol monomer provides barrier, so the content of ethylene monomer increases, so does the oxygen transmission coefficient.For example, when EVOH contains 29% ethylene, its oxygen transmissibility coefficient is 0.1ml. Mm/m2d.mpa, while when ethylene content is 38%, its oxygen transmissibility coefficient is 0.4ml. Mm/m2d.mpa.

EVOH is hydrophilic and hygroscopic due to the presence of hydroxyl in the molecular structure of the resin. Pure EVOH products have high water absorption, which seriously affects the barrier property. Therefore, EVOH cannot be used alone, and is often used as an intermediate material and composite with other materials to prevent its water absorption from affecting its barrier property.And the barrier of EVOH will decrease as the temperature increases.It can prevent O2 and other gases from permeating into the packaging bag, and also prevent the air from escaping from the bag.Its air resistance is 100 times higher than PA and 10,000 times higher than PE and PP.