The emergence and development of the hottest multi

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The emergence and development of multi-functional multi-layer coextrusion packaging film (II)

multi layer coextrusion extrusion composite

this kind of extrusion composite is one of the main production methods of composite flexible packaging materials. It uses more than three extruders to melt resin raw materials with different functions, such as PA, PE, PP, etc., respectively, which has no significant impact on the unit cost. It is extruded through their respective flow channels at the die head, and then through blow molding, Cooling compound together

because the multi-layer coextrusion film has various raw material properties, it can well meet the functional requirements of packaging. It can replace the dry-type composite film or reduce the number of dry-type composite films. It has the characteristics of environmental protection and energy saving. Therefore, the multi-layer and multi-function of this co extrusion composite is the mainstream direction of development in the future. The common structures of products are:

PE/tie/PA/tie/PE (PA) high barrier, medium strength

PE/tie/EVOH/tie/pe high barrier, medium strength

PA/EVOH/PA/tie/EVA high barrier, high strength

among them:

PA, EVOH provide good barrier performance, which can block oxygen, aroma, etc

pe, EVA and other polyolefins can provide excellent water vapor barrier ability and have good heat sealing performance

at the same time, it can also meet the requirements of pasteurization (85 ℃), 100 ℃ boiling sterilization, ultraviolet sterilization, microwave sterilization and so on. If the sterilization condition is 121 ℃, high temperature cooking for 30min, PE can be replaced with high temperature resistant pp. in addition, if printing is required, corona treatment can be used

for different food packaging requirements and packaging equipment, you can also adjust the material of the heat sealing layer to meet:

EVA low temperature heat sealing

m-LLDPE anti pollution heat sealing

EAA oil products heat sealing

surly body fitting, anti pollution heat sealing

multi layer co extrusion multi-functional thin film packaging material can well meet the needs of various packaging occasions, and has incomparable advantages over dry composite film, By adjusting the thickness of the barrier layer and using a variety of barrier materials to make the production process more efficient, you can flexibly design films with different barrier properties, and flexibly replace and allocate heat seal materials to meet the needs of different packaging, replacing many packaging markets based on dry composite

multi-layer coextrusion -- the green revolution of the composite process

multi-layer coextrusion is a complete green composite production process, especially for the current food packaging industry, the raw materials used are generally materials certified by the U.S. Food and health safety agency. The raw materials are uniformly supplied to each layer through a special transmission pipeline declared by Weiner. There is no exposure of raw materials and no environmental pollution in the processing process. The adhesive layer is a modified LLDPE raw material. The soft and flexible pet aerogel also provides greater comfort, which is non-toxic to the environment, food and human body, and does not involve the so-called solvent residue phenomenon of traditional dry compounding. It has no exhaust gas pollution. It is also different from dry compounding, solvent-free compounding and general single-layer extrusion compounding processes. It requires drying oven for treatment, so it consumes less energy

in addition, the multi-layer coextrusion composite process also has the following advantages:

low cost

the multi-layer coextrusion composite process uses a variety of resins with different functions, and only one blow molding process can be used to make multi-functional composite film products, which can reduce production costs. In addition, on the premise of meeting the use requirements of customers, the resin raw materials with required properties can be reduced to the minimum thickness, and the single layer can be as thin as 2~3 m, which can greatly reduce the use of expensive resin and reduce the material cost

flexible structure

multi layer coextrusion technology can match a variety of raw materials in different combinations, make full use of raw materials with different properties, and form at one time, which is not limited by relevant product specifications in the market, and effectively meet the needs of different packaging occasions. The more levels, the more flexible the structural design and the lower the cost

high composite performance

the coextrusion composite process combines the molten adhesive with the base resin. The peel strength of this process is very high, usually up to 3n/15mm or more, and it can't even peel, which is suitable for general packaging materials. For products requiring high peel strength, thermal adhesive resin can be added for compounding, and the peel strength can reach 14n/15mm or even higher

it has a wide range of uses and a wide use environment.

multi layer coextrusion composite products can cover almost all packaging fields: food, daily chemical products, beverages, drugs, protective films and even aerospace products. At present, many dry composite products in China have adopted coextrusion technology abroad. Toothpaste tubes, paper plastic aluminum composite products, aerospace and other products that cannot be produced by the dry composite process are also achieved by the coextrusion composite process. With the in-depth research and continuous innovation of coextrusion composite resin, process and equipment, multi-layer coextrusion composite will expand to a broader range

development trend of multi-layer coextrusion technology

at present, advanced countries such as Europe and the United States have been constantly emphasizing the requirements of environmental protection and health, and multi-layer coextrusion and solvent-free dry compounding are gradually replacing solvent-based dry compounding technology. With the merger of China's health supervision institutions and medical and health supervision institutions, the requirements for the health performance of packaging materials will be more stringent in the future. China's flexible packaging composite market will undergo a major structural adjustment and will gradually be in line with international standards, which provides a greater development space for multi-layer coextrusion composite technology

in order to realize products with multi-layer structure, plastic resins for multi-layer coextrusion composites are also being introduced. In addition to the commonly used LDPE and PP thermal bonding resins, they are also developing towards other thermoplastic resins. It is expected that in the near future, when LDPE, LLDPE, PS, PA, PC, PVA, EVOH, PVDC and other functional resins for extrusion composites can be produced on a large scale, multi-layer coextrusion composite film materials will have greater development

in order to improve the production efficiency, the process technology of multi-layer coextrusion is also constantly innovated. In addition to the use of new functional resin materials, various process methods to improve the properties of extrusion composites are also being used. For example, changing the molecular polarity of blow molded film or improving the surface properties of substrate film through process methods to improve the peel strength of extrusion composite, and some products can also significantly reduce costs

at present, the technical level of multi-layer coextrusion is not high in China. The multi-functional multi-layer coextrusion packaging film is in the growth period of promotion and use. The barrier film produced in China is mostly used in the packaging of low-end products, and there is still a big gap compared with developed countries. The future development direction is to improve the performance of products through the improvement of equipment and process, meet the needs of the market, expand the scope of use, realize the structural change of multi-layer coextrusion composite products, and gradually catch up with the trend of world development. In the next few years, we will vigorously develop multi-layer coextrusion composite technology, and resin materials will be mainly modified by blending to meet the composite requirements of more products

information source: packaging materials and containers

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