Current status and development trend of EVOH packaging materials at home and abroad
EVOH not only has good barrier properties to gases, solvents, etc., but also has excellent oil and organic solvent resistance. It has excellent antistatic properties, and it can also be regenerated without chlorine and dioxins. It is green. product. As a barrier material with excellent performance, it can be widely used in various types of packaging. The disadvantage is that the EVOH barrier performance is greatly affected by the environment, and when the humidity is > 60%, the barrier performance is significantly reduced.
Since EVOH is hydrophilic and its gas barrier properties are affected by humidity, which hinders the expansion of its application range, EVOH is mostly used in the manufacture of intermediate layers of composite packaging materials, and is used in combination with other materials with good moisture resistance, such as EVOH/polymerization. Propylene (PP), EVOH/polyethylene , etc.
Coextrusion with PP PE
Since EVOH is hygroscopic and the barrier property is greatly reduced with increasing humidity, in order to prevent EVOH from affecting barrier properties due to moisture absorption, it is usually combined with a polyolefin having good water resistance to form a multilayer co-extruded composite film, and its typical structure. There are low density polyethylene (LDPE) / EVOH / LDPE, LDPE / EVOH / ethylene - vinyl acetate copolymer (EVA), PP / EVOH / PP and so on.
Coextrusion with nylon (PA)
EVOH has a very good affinity with PA, can be blended in any proportion, and has excellent adhesion. No cohesive layer is required between the two layers during coextrusion. For EVOH, it can be combined with PA to produce a tough composite film; for PA, it is easy to maintain residual shape due to its heat forming, it is difficult to maintain the shape of the molding, and it is characterized by high glass transition temperature after compounding with EVOH. More adapt to the requirements of molding processing. Representative structures are: PA/EVOH/EVA, PA/EVOH/LDPE, P A / E V O H / L D P E , polypropylene (P E) / P A /EVOH/PA/PE, and the like.
contact person: Bee
phone/whatsapp/wechat: 0086 13416312953