EVOH multi-layer co-extruded composite film
DATE：2019/9/12 8:46:41 / READ： / SOURCE：This station
EVOH multi-layer co-extruded composite film
(1) Composite with polyolefin
Since EVOH is hygroscopic, the gas barrier property will be greatly reduced. In order to prevent EVOH from affecting its gas barrier property due to moisture absorption, it is usually combined with a polyolefin having good water resistance to form a multilayer co-extruded composite film, which is typical. The structure is LDPE/EVOH/LDPE, LDPE/EVOH/EVA, PP/EVOH/PE, and the like.
However, since the bonding between the EVOH and the polyolefin layer is not good, the interlayer is inserted into the bonding layer, thereby forming a 5-layer structure such as PP/AD/EVOH/AD/PP (AD stands for the adhesive layer resin).
(2) EVOH and nylon composite
EVOH has a very good affinity with nylon and can be miscible in any proportion, so that the adhesion is excellent. In the co-extrusion compounding, no bonding layer is required between the two layers, and the brittleness of EVOH is enhanced by nylon to obtain a tough composite film. For the sheet for thermoforming, the glass transition temperature of EVOH is high, so it can be formed after thermoforming. Maintain shape and can be applied to bags or deep drawing containers. In addition, in the case of nylon, residual deformation is liable to occur during heat molding, and the glass transition temperature is lowered after moisture absorption, and large shrinkage stress is likely to occur, and it is difficult to maintain the molded shape. Combined with EVOH, it is correspondingly enhanced and adapted to the requirements of molding processing. Representative structures are: PA/EVOH/EVA, PA/PVOH/IO, PA/EVOH/LDPE, PA/EVOH/LLDPE, etc.
The structure and main uses of the EVOH gas barrier coextruded composite film are shown in Table 7-5-3, in which deep-drawing vacuum packaging such as thin ham is used most, nearly half of the total amount. Followed by impregnated materials, water-containing foods such as sauces, and again processed meat and body packaging. As a special application product, it is a composite substrate which is combined with various films, foamed PS, paper, wood, steel plate, aluminum plate, metal foil, etc. by printing.
(1) Composite with polyolefin
Since EVOH is hygroscopic, the gas barrier property will be greatly reduced. In order to prevent EVOH from affecting its gas barrier property due to moisture absorption, it is usually combined with a polyolefin having good water resistance to form a multilayer co-extruded composite film, which is typical. The structure is LDPE/EVOH/LDPE, LDPE/EVOH/EVA, PP/EVOH/PE, and the like.
However, since the bonding between the EVOH and the polyolefin layer is not good, the interlayer is inserted into the bonding layer, thereby forming a 5-layer structure such as PP/AD/EVOH/AD/PP (AD stands for the adhesive layer resin).
(2) EVOH and nylon composite
EVOH has a very good affinity with nylon and can be miscible in any proportion, so that the adhesion is excellent. In the co-extrusion compounding, no bonding layer is required between the two layers, and the brittleness of EVOH is enhanced by nylon to obtain a tough composite film. For the sheet for thermoforming, the glass transition temperature of EVOH is high, so it can be formed after thermoforming. Maintain shape and can be applied to bags or deep drawing containers. In addition, in the case of nylon, residual deformation is liable to occur during heat molding, and the glass transition temperature is lowered after moisture absorption, and large shrinkage stress is likely to occur, and it is difficult to maintain the molded shape. Combined with EVOH, it is correspondingly enhanced and adapted to the requirements of molding processing. Representative structures are: PA/EVOH/EVA, PA/PVOH/IO, PA/EVOH/LDPE, PA/EVOH/LLDPE, etc.
The structure and main uses of the EVOH gas barrier coextruded composite film are shown in Table 7-5-3, in which deep-drawing vacuum packaging such as thin ham is used most, nearly half of the total amount. Followed by impregnated materials, water-containing foods such as sauces, and again processed meat and body packaging. As a special application product, it is a composite substrate which is combined with various films, foamed PS, paper, wood, steel plate, aluminum plate, metal foil, etc. by printing.
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