The hottest new trend of fast food packaging 2

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New trend of fast food packaging (2)

composite packaging materials with inorganic coating in order to manufacture highly transparent composite packaging materials with the same barrier as composite packaging materials containing aluminum foil, people have developed a base film containing evaporated aluminum oxide layer or silicon oxide layer (using physical or chemical methods, plating a dense layer of silicon oxide or aluminum oxide on the surface of PET film). The made composite film has extremely high oxygen resistance, moisture resistance, oxygen permeability and moisture permeability, and also has a high degree of transparency. The packaged goods can be clearly seen through the packaging, which has a good display effect on the goods. In addition, because the composite does not contain aluminum layer and has excellent microwave permeability, it can be well used in microwave food where aluminum composite packaging materials cannot be used

the common limitation in performance of composite packaging materials containing aluminum foil and inorganic coating is that they have the tensile molding performance of ordinary thermoplastic plastics (composite packaging materials containing aluminum foil cannot be thermoformed; composite packaging materials containing inorganic coating will have a significant decline in barrier performance and lose use value after thermoforming)

composite packaging materials containing aluminum foil and inorganic coating, especially composite packaging materials containing inorganic coating, in addition to the above-mentioned characteristics, they also have a common advantage, that is, they have good adaptability to environmental protection and easy handling of packaging waste, so they are generally considered to be one of the most promising composite packaging materials

in the past, when producing composite packaging materials containing aluminum foil and inorganic coating, solvent based adhesives were often used to let the material testing machine continue to carry out the tensile dry composite process on the standard tensile samples. The discharge of the solvent qb/t 2710 ⑵ 005 leather physical and mechanical experiments will pollute the surrounding environment, and the residual solvent will degrade the hygienic performance of the packaging materials. With the continuous improvement of people's awareness of environmental protection, solvent-free compounding and dry compounding with water binder have been favored by people, and there is a trend to gradually develop to the mainstream process

all plastic barrier composite packaging materials high barrier all plastic composite packaging materials

industrialized high barrier all plastic composite packaging materials. The commonly used barrier resins are usually polyvinylidene chloride (PVDC), ethylene vinyl alcohol copolymer (EVOH), aromatic nylon MXD6, etc. They can not only produce packaging materials with good transparency and high barrier, but also their thermoplastic properties can be co extruded, and the required composite packaging materials can be directly produced from plastic pellets to implement cleaner production. Because of their thermoformability, they can be deep drawn and processed into containers of the desired shape

polyvinylidene chloride is a variety with outstanding advantages and disadvantages. It is the only polymer commonly used in the packaging field that has a high barrier to oxygen and water vapor at the same time. Although its molding performance is worse than that of ordinary general thermoplastic, under specific molding conditions, it can not only produce single-layer flat film and pipe film, but also produce multi-layer coextrusion composite film by coextrusion method, but also by lotion (or solution) coating method, with relatively low cost Polyvinylidene chloride coating containing high barrier packaging materials, therefore, polyvinylidene chloride has been regarded as one of the most promising barrier packaging materials. However, the environmental adaptability and thermal stability of PVDC are very poor, and the waste packaging can not be recycled through melting granulation. And it is not easy to decompose, and will not be absorbed by nature and return to nature; During incineration, toxic and harmful substances such as hydrogen chloride and dioxin will be produced. Although through people's efforts, the tail gas absorption incinerator can be effectively (8) cover the machine with a dust cover after the experiment To deal with the hydrogen chloride produced during its incineration, but so far no effective treatment method has been found for the strong carcinogen dioxin, so people have questioned the use of polyvinylidene chloride packaging materials. If there is no major breakthrough in the disposal technology of packaging waste, the application prospect of polyvinylidene chloride in packaging is not optimistic

ethylene vinyl alcohol copolymer has the same high oxygen resistance as polyvinylidene chloride. Although its ability to block water vapor is poor, it can be compounded with polyolefins such as polyethylene to produce composite materials with high water vapor barrier. Its molding performance is very excellent. It can be processed and molded by conventional thermoplastic processing technology and equipment, and has excellent environmental adaptability. It can be recycled by melting granulation, and heat energy can be recovered by incineration. During incineration, only carbon dioxide and water are produced without any substances harmful to human health and the natural environment. However, due to its high price, its application is greatly limited. Although the progress of coextrusion process and equipment in recent years has reduced the barrier layer in the composite to 5%-15% of the total thickness, creating better conditions for the promotion and application of ethylene vinyl alcohol copolymer packaging materials, it is still limited to those occasions with high added value and other packaging materials are not competent. The large-scale application of vinyl alcohol ethylene copolymer still needs a substantial reduction in its cost

the oxygen resistance of aromatic nylon MXD6 under standard conditions is slightly lower than that of ethylene vinyl alcohol copolymer, but after cooking treatment, the time required to restore the original high oxygen resistance is much shorter than that of ethylene vinyl alcohol copolymer. At the same time, it also has good molding processing and environmental adaptability, so it is recommended for food packaging requiring cooking processing. At present, the main obstacle to its application is also the cost

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