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What are the common high barrier film materials?

BY:common problem CLICK:476 POST:2021-05-31
PVA coated high barrier film


PVA coated high barrier film is made by printing and compounding PVA coated with nano inorganic matter on polyethylene film, which solves the technical bottleneck of poor barrier performance of three-layer polyethylene co extrusion packaging film on the premise of little increase in cost. In 2008, after three years of hard work and independent innovation, the scientific research personnel of Cangzhou Jinlong Plastics Co., Ltd. finally took the lead in bringing the product with national patent, PVA coated high barrier milk film, to the market in China. The oxygen blocking rate is less than 2cm3 / (M2 · 24h · 0.1MPa), the barrier performance is not only better than EVOH five layer co extrusion film, but also the packaging cost is greatly reduced, which can not only ensure all the quality requirements of aseptic packaging, but also greatly reduce the cost of aseptic packaging in food processing enterprises, It can be used to pack drinks, juice, milk, soy sauce and vinegar.


PVDC (polyvinylidene chloride)


PVDC resin is often used as composite material, monomer material and coextrusion film sheet, which is the most widely used high barrier packaging material. Polypropylene (OPP) and polyethylene terephthalate (PET) are used as substrates for PVDC film. Due to the high softening temperature of pure PVDC, close to its decomposition temperature and poor compatibility with general plasticizers, it is difficult to heat form and apply directly. Most of the PVDC films used in practice are copolymers of vinylidene chloride (VDC) and vinyl chloride (VC), as well as films with excellent barrier properties made by copolymerization with methyl acrylate (HA).


PVDC is characterized by low permeability, barrier and chemical resistance. With the introduction and development of ham sausage processing technology, PVDC has been developed in China.


In 2002, the domestic production of PVDC was about 20000 tons. At present, it has been widely used in food, cigarette, beverage preservation and taste separation, as well as moisture-proof packaging in chemical, pharmaceutical, electronic and military industries.


The single-layer PVDC film is made by biaxial stretch blow molding. It has shrinkage, barrier and water resistance, and does not decompose under microwave heating. It is widely used in household preservative film; PVDC and polyethylene (PE), polypropylene (PP), polystyrene (HIPS) and other synthetic resin multi-layer extrusion used for vacuum dairy products, jam and other packaging, its tensile properties are good, suitable for larger volume packaging; The composite sheet of PVDC, PE and PVC is suitable for the packaging of easily hygroscopic and volatile drugs. At present, many domestic 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), etc; Coating can be single-layer or multi-layer, generally single-layer coating is 2.5 μ M can have a good barrier effect.


EVOH (ethylene / vinyl alcohol copolymer)


EVOH has always been the most widely used high barrier material. The film types of this material are not only non stretching type, but also biaxial stretching type, aluminum evaporation type, adhesive coating type, etc. in biaxial stretching type, heat-resistant type is also used for aseptic packaging products.


The barrier performance of EVOH depends on the ethylene content. Generally speaking, when the ethylene content increases, the gas barrier performance decreases, but it is easy to process.


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 can and cooking bag, packaging dairy products, meat, canned fruit juice and condiments; In terms of non food, it is used for packaging solvents, chemicals, air conditioning structural parts, gasoline barrel lining, electronic components, etc. In terms of food packaging, EVOH plastic containers can completely replace glass and metal containers. A number of domestic aquatic companies use PE / EVOH / PA / rvoh / PE five layer coextruded film vacuum packaging for seafood export. While speeding up the research of EVOH composite films, EVOH tensile orientation is also being studied abroad. The gas barrier performance of the new EVOH films is three times that of the existing high-performance non tensile EVOH films. In addition, EVOH can also be used as a barrier material coated on other synthetic resin packaging materials to enhance the barrier performance.


Nylon packaging materials


Nylon packaging materials used to use "nylon 6". But the air tightness of nylon 6 is not ideal. There is a kind of nylon (mkd6) polycondensated from m-dimethylamine and adipic acid. Its air tightness 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, MXD6 nylon is widely used as a substitute for PVDC film due to its outstanding environmental protection problems. MXD6 nylon and EVOH are used as a new kind of nylon film with high barrier property. The methods of compounding include multilayer compounding, blending and stretching of MXD6 nylon and EVOH.


Inorganic oxide coating film


The so-called coating films made by coating SiOx (silicon oxide) on other substrates have attracted more and more attention in the market. In addition to silicon oxide coating, there are also alumina evaporated films. The air tightness of the coating 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 has developed rapidly. High barrier packaging materials, such as EVOH, PVDC, PA, pet multilayer composites and siloxane evaporated film, have been further developed, especially the following products: MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; MXD6 polyamide packaging materials; Silicon oxide thin films, etc.
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