PVDC (polyvinylidene chloride)
PVDC resin is often used as composite material or monomer material and coextrusion film sheet, which is the most used high barrier packaging material, especially PVDC coating film.
Polypropylene (OPP) and polyethylene terephthalate (PET) are used as substrates for PVDC coating. Due to the high softening temperature of pure PVDC, close to its decomposition temperature and poor solubility with common plasticizers, it is difficult to heat and directly apply.
Most PVDC films used in practice are copolymers of vinylidene chloride (VDC) and vinyl chloride (VC), and films with excellent barrier properties made by copolymerization with methyl acrylate (HA).
PVDC is characterized by low permeability, barrier and chemical resistance. PVDC has been developed with the introduction of ham sausage processing technology in China.
Single layer PVDC film is prepared by biaxial tensile blow molding. It has the properties of shrinkage, barrier and water resistance. It does not decompose under microwave heating. It is widely used in household preservative film;
PVDC and synthetic resins such as polyethylene (PE), polypropylene (PP), polystyrene (HIPS) are extruded by multi-layer extrusion, which can be used for packaging of vacuum dairy products and jam;
The composite sheet of PVDC, PE and PVC is suitable for packaging of hygroscopic and volatile drugs.
At present, many domestic scientific research institutions and manufacturers focus on PVDC and other resin composite laminated film technology and high temperature resistance technology of composite film.
PVDC is used in a variety of substrates such as PE, PP, PVC, polyamide (PA), polyethylene terephthalate (PET) and so on. Taking biaxially oriented polypropylene film as an example, the oxygen permeability and water permeability can be reduced by 1000 times and 3 times respectively; the coating can be single-layer or multi-layer, and the single-layer coating of 2.5 μ M can have good barrier effect.
EVOH (ethylene / vinyl alcohol copolymer)
EVOH is the most widely used high barrier material. In addition to the non tensile film type, there are biaxial tensile type, aluminum evaporation type, adhesive coating type, etc., and the heat-resistant type is also used for aseptic packaging products.
Generally speaking, however, the ethylene barrier properties decrease when the ethylene content increases.
EVOH is characterized by excellent gas barrier and excellent processability. In addition, it has excellent transparency, gloss, mechanical strength, scalability, wear resistance, cold resistance and surface strength.
In the field of packaging, EVOH is made into composite film intermediate barrier layer, which is used in all hard and soft packaging; in the food industry, it is used for aseptic packaging, hot cans and cooking bags, and for packaging dairy products, meat, juice cans and condiments; in non food, it is used for packaging solvents, chemicals, air conditioning structural parts, gasoline barrel lining, electronic components, etc.

In food packaging, EVOH plastic containers can completely replace glass and metal containers. Many domestic aquatic companies use PE / EVOH / PA / rvoh / PE five layer coextrusion film vacuum packaging for seafood export.

At the same time, EVOH stretching orientation is also studied in foreign countries. The gas barrier performance of the new EVOH film is three times higher than that of the existing high-performance non stretched EVOH film.
In addition, EVOH can also be used as barrier material on other synthetic resin packaging materials to enhance the barrier performance.
Nylon packaging materials
Nylon packaging materials used to be "nylon 6". But the air tightness of nylon 6 is not ideal.
There is a kind of nylon (mkd6) which is polycondensated from m-dimethylamine and adipic acid. The air tightness of mkd6 is 10 times higher than that of nylon 6. At the same time, it also has good transparency and puncture resistance. It is mainly used in high barrier packaging film and food soft packaging with high barrier requirements. Its food hygiene is also approved by FDA.
The biggest characteristic of the film is that the barrier does not decrease with the increase of humidity. In Europe, due to the outstanding environmental protection problems, MXD6 nylon is widely used as a substitute for PVDC films.
MXD6 nylon and EVOH composite film with bidirectional elongation, as a high barrier nylon film. The composite methods include multi-layer compounding, and blending and stretching of MXD6 nylon and EVOH.
Inorganic oxide coating film
More and more attention has been paid to the so-called coating films prepared by coating SiOx (silicon oxide) on other substrates. Besides silicon oxide coating, there are also alumina evaporation films. The air tightness of the film is the same as that of the silicon oxide coating obtained by the same method.
In recent years, the technology of multilayer compounding, blending, copolymerization and evaporation plating has developed rapidly. High barrier packaging materials such as ethylene glycol copolymer (EVOH), polyvinylidene chloride (PVDC), polyamine (PA), polyethylene terephthalate (PET) multilayer composite materials and silicon oxide film have been further developed, especially the following products are more attractive: MXD6 polyamide packaging material; silicon oxide evaporation film, etc.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
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