Research on the way and technology application of

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Research on the way and technology application of heat shrinkable packaging (III)

2 the equipment used in heat shrinkable operation is called heat shrinkable packaging machine (also known as heat shrinkable channel). As shown in Figure 9, it is composed of conveyor belt, heating channel and cooling device. During the heat shrinking operation, put the prepackaged parts on the conveyor belt and run at the specified speed into the heating channel, and use the hot air to blow to the package for heating. The film outside the product automatically shrinks and wraps the product tightly. After the heat shrinking is completed, the package is transferred out of the heating channel and removed from the conveyor belt after natural cooling. It can also be taken out according to the size of the product, the type of film and the heat recovery temperature of the film, Use a cooling fan to accelerate the film cooling after sending out the heating channel

the heating channel is a box device with thermal insulation materials on the inner wall. In order to ensure that the hot air is removed from the following three aspects and blown evenly onto the packaging, the heating channel adopts an automatic temperature adjustment device to ensure that the temperature in the channel is constant (the temperature difference is ± 5 degrees), and adopts a forced circulation system to circulate the hot air. When heating, the hot air speed, flow, conveyor structure, inlet and outlet shape and material have an impact on the shrinkage effect. Due to the different characteristics of various films, the appropriate heat shrinkable channel parameters should be selected according to the characteristics of various films. Table 1 shows the relationship between the main parameters of commonly used shrink films and shrink channels

in addition to using heat shrinking channels for heat shrinking operations, portable hot air guns can be used for on-site heat shrinking of products packaged on large pallets or single shaped products with large volume. This operation method is simple, rapid, convenient and economical

3 development of heat shrinkable packaging technology

heat shrinkable packaging is more and more popular with businesses and consumers because of its distinctive characteristics and unique charm. According to the prediction of relevant experts, heat shrinkable packaging will enter an explosive growth stage in the next few years

3.1 LLDPE cold shrinkable film packaging technology

lldpe cold shrinkable film packaging technology is developed on the basis of heat shrinkable packaging and stretch packaging technology. At present, pallet packaging generally adopts open end heat shrinkable packaging or stretch film winding packaging. For heat shrinkable packaging with an open tray at one end, the film must be made into a large bag with a square bottom first, and then the large bag is sleeved on the stacked commodity tray from top to bottom, and then heat shrinkable. Due to the need for heat shrinkable channels, energy consumption, equipment investment and ground occupation are large, and it is difficult to achieve continuous research and high-speed production led by Professor paulcurtis of Imperial College London and the British Defense Science and technology laboratory. The PE stretch film packaging is to use manual or stretch packaging equipment to wrap one layer of PE stretch film on the pallet goods. It is not only time-consuming and relatively expensive, but also the packaging quality with low transparency often causes inconvenience to the warehouse keeper in the inventory. The customer must completely tear off the PE stretch film when accepting the goods, which is both laborious and time-consuming. In order to overcome the defects brought by traditional heat shrinkable packaging and stretch packaging pallets, a new LLDPE cold shrinkable film packaging technology has been widely used in European and American beverage enterprises. This new packaging technology absorbs the advantages of traditional heat shrinkable packaging and stretch packaging, and has obvious advantages in terms of packaging effect, packaging cost savings, packaging speed and so on:

1) the thickness of cold shrinkable film is only 0.1mm, LLDPE oil circuit system has serious oil leakage or oil pipe is broken. The contraction ratio of cold shrinkage film is 17% - 20%. It can be stretched or contracted without heating. The packaging effect has high transparency, which is convenient for users' warehouse management

2) the price of LLDPE cold shrink film is: 10-15 yuan/kg, and the amount of film used per pallet is about 500-600g. The packaging cost is greatly saved

3) fully automatic operation. The maximum production capacity is 6O pallets/h, which varies slightly according to the height of the pallet stack

4) the film is made into a cylinder in advance, and the bag formed after the top is sealed can be waterproof

5) suitable for transportation. Stacked items are tightly wrapped by cold shrink film, which can effectively prevent falling off<6. Adjust the clearance of each plug iron/p>

6) the cold shrink film does not need to use heat energy, which can save energy and completely eliminate the possibility of fire or explosion

7) double headed design, which can automatically select the most appropriate film according to the size of the tray

(to be continued)

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