Domestic high barrier materials in common use
1. Aluminum foil advantages: blocking performance, best can cooking, and can effectively block the ultraviolet ray. Inadequate: opaque, folding resistance, high cost, can not be used in microwave heating. At present most of uht using tetra brick and tetra pak pillow packaging, in 2004 the aluminum composite paper-plastic packaging the consumes around 11 billion, a total of 10 g per bag material calculation, equal to 110000 tons. Because the packaging material containing metal layer ( Aluminum foil) Is not easy to degrade, composite material of aluminum foil in China at present and have no ability to separation, resulting in the structure of the aluminum paper-plastic composite material and the structure of the aluminum plastic composite materials of waste recycling, can neither can't burn, great harm to the environment protection. 2. Aluminum plating film advantages: good folding in aluminum foil, blocking performance close to the aluminum foil, blocking ultraviolet, aluminum plating processing and low cost. Inadequate: opaque, coating strength, poor ( Under water after the aluminum layer is easy to fall off automatically) , can not be used in microwave heating. 3. Advantages: EVOH five layers co-extrusion film is excellent blocking performance, it has excellent resistance to oil and organic solvent resistance, antistatic properties, can be recycled, burning only produces CO2 and H2O, is a good green environmental protection packaging materials. Inadequate: environment humidity more than 50%, the blocking performance dramatically, so it should not be used alone. For imported EVOH resin, multi-layer co-extrusion equipment investment is very expensive, causes the product cost is very high. 4. PVDC coated film advantages: at the same time has good cut off oxygen and barrier performance of water vapor, coating can be heat sealing, lower cost. Inadequate: coated need special equipment; When burning, not melt granulation recycling, waste to produce hydrogen chloride, such as dioxin toxic to humans and the surrounding environment and harmful substance. 5. Alumina silica films and plated film with silica and alumina plating film good transparency, resistance to oxygen, the wet resistance and other performance is very good, but because of the extremely expensive equipment investment, combined with the difficulty of processing technology is very high, so the product cost is extremely high. There is currently no unit production, domestic products are imported from abroad. 6. New high barrier materials modified poly (vinyl alcohol) ( PVA) Coating film ( 1) Oxygen resistance excellent performance of modified poly (vinyl alcohol) ( PVA) Coating composite membrane for oxygen, nitrogen, hydrogen and carbon dioxide has excellent barrier property, the oxygen resistance performance is better than that of PVDC ( Poly (vinylidene chloride) The coating film, but also better than that of EVOH ( Ethylene/vinyl alcohol copolymer) Five layers co-extrusion film. Its oxygen resistance performance is the best in all kinds of resin film, with aluminum foil, glass, with aluminum oxide film and silicon oxide film plating. The comparison of several kinds of material oxygen resistance performance. Unit: / cm3 ( m2•24h•0. 1MPa) 。 ( 2) Low cost poly (vinyl alcohol) ( PVA) Coating composite film production cost is much lower than paper lu: su composite, lu: su composite packaging materials production cost, far lower than EVOH five layers co-extrusion film production costs, and lower than the adoption of PVDC coated composite film cost. ( 3) Application is simple to use the flexible packaging production enterprises existing dry composite machine, coating machine, wet composite machine, composite extrusion machine equipment all can achieve satisfied effect. Of the modified PVA glue solution not crust, viscosity has no obvious rise phenomenon in the process of normal use, the coating layer is very thin, but the coating thickness uniformity is still very good. ( 4) First-class environmental protection poly (vinyl alcohol) ( PVA) High block composition of water-based coating liquid as carbon, oxygen, hydrogen and silicon, biodegradable and recycled, recyclable burns only generates carbon dioxide and water, and does not produce other substances harmful to environment and human health, no pollution, is an ideal environmental protection high barrier packaging materials. ( 5) With sweet good performance with excellent performance, may in the longer term the rich flavour of bag food, at the same time can effectively stop the packing material outside the smell into the sack. ( 6) Other colorless, good transparency. It has excellent resistance to oil, organic solvent resistance performance. Has a good antistatic performance. Can be used in microwave heating for packaging of food metal detection. Because in the fluid of the PVA water-based coating joined the nanoscale inorganic powders, after the film's resistance to water, ultraviolet and infrared light reflective, abrasion resistance, permeability resistance, PVA coating and the basement membrane properties, such as bonding strength have got obvious improvement. : due to the thin coating, the coating poor heat sealing; Though after modification, the water sensitivity significantly lower PVA coating, to keep the best effect of the resistance of oxygen, still with polyolefin plastic film ( Such as BOPP, CPP, PE, etc. ) To protect it as well.
