1. Characteristics of Heat Shrink Packaging and Stretch Wrapping Heat shrink packaging can be widely and rapidly developed, mainly because it has many excellent features:
(1) Special-shaped goods that are difficult to pack in general methods, such as vegetables, fruits, fish, toys, and gadgets.
(2) Shrink film is generally transparent, after heat shrink, close to the goods, can fully display the appearance of the goods, due to the more uniform shrinkage, and the material has a certain degree of toughness, edges and corners are not easy to tear.
(3) The use of the nature of shrinkage makes it easy to package together pieces of loose goods, such as several cans, several cassettes of audio tape, and sometimes light boxes to save the cartons.
(4) It can extend the shelf life of foods and is suitable for food preservation, low temperature storage, and prevention of excessive drying of frozen foods, providing convenience for supermarkets and retailers.
(5) Sealed, moisture-proof and anti-pollution can be piled in the open air, saving the storage area, such as cement, fertilizer, etc., which are both solid and convenient.
(6) The packaging process and equipment are simple, versatile, easy to implement mechanization, save labor and packaging costs, and can partially replace corrugated boxes and wooden boxes.
(7) Shrink packaging not only fastens the items to be packaged together, but also the film itself has cushioning properties and toughness, which can prevent the loss of products due to vibration and impact during transportation.
(8) For bulky products, on-site shrink packaging methods can be used, and the process and equipment are very simple. Such as packaging boats and cars.
(9) Shrink-wrapped packages of granular, powder, or regular-shaped goods are not as fast and convenient as cartoning, packing, bagging, and wrapping.
The need for heat-shrink tunnels, energy consumption, investment and workshop area are large, and it is difficult to achieve continuous high-speed production.
Many of the characteristics of stretch-wrapping are similar to those of shrink-wrapping because stretch-wrapping comes from shrink-wrapping. Because of this, stretch-wrapping has many advantages over shrink-wrapping.
(1) Because there is no need for heat-shrinking equipment, equipment investment, energy, and equipment maintenance costs are saved.
(2) Because it is not heated, it is suitable for packaging products that are afraid of heat, such as fresh meat, vegetables and frozen foods.
(3) The wrapping force can be accurately controlled to prevent the product from being crushed.
(4) The film is transparent, allowing you to see the product for easy purchase and inventory.
(5) It can prevent theft, fire, shock and vibration.
(6) The moisture resistance is worse than that of shrink packaging, and an additional film is required at the top of the goods stacked in the transportation, which makes the operation inconvenient.
(7) Because the stretched film is self-adhesive, when many packages are piled together, they may be damaged by the adhesive during handling.
Therefore, heat shrink packaging and stretch packaging have their advantages and disadvantages. To further strengthen understanding, we can focus on a simple comparison of them, as shown in Table 12-3.
Table 12-3 Â Â Comparison of shrink packaging and stretch packaging
Adaptability to the product:
(1) For regular shaped and profiled products
(2) For fresh fruits and vegetables
(3) Sales packages for single and multiple products;
For pallets with and without pallets
(4) For frozen or afraid of heat products
Can be particularly suitable
The goods can be fastened on the pallet
Not suitable can be particularly suitable
Adaptability to the circulation environment
(1) Package storage place
(2) Moisture resistance (refers to transport packages)
(3) Breathability (refers to transport packages)
(4) Low temperature operation
Warehouse, open storage can be, not afraid of the sun and rain, save storage space
it is good
Can be sealed on six sides
Films exposed to sunlight or hot weather will only relax in warehouses
Usually only side wrapping,
When necessary, five-sided sealing
it is good
General top is not sealed
Can be operated in the freezer room 3
Equipment investment and packaging costs
(1) Equipment investment and maintenance costs
(2) Energy consumption
(3) Material costs
(4) Payback period
Needs heat shrink equipment, investment and costs are much higher
No heating, low investment and costs
Less than 25% less shrink wrap
Short 4 Wrapping stress is not easy to control, but relatively uniform
Easy to control, but the edges and corners are too stressful and vulnerable.
Packages do not stick to each Other
The film is self-adhesive, easy to bond between packages, easy to tear during handling. Available with self-adhesive film on one side when necessary. 6 Film inventory requires multiple film thicknesses. One film thickness can be used for different products.
2. Heat Shrink and Stretch Packaging Selection Principles When selecting stretch and heat shrink packaging, first consider the following aspects:
(1) The principle of adapting as much as possible to the product.
(2) The principle of adapting as much as possible to the circulation environment.
(3) The principle of minimizing equipment investment and packaging costs.
(4) The principle of a wide range of packaging materials, variety, and convenient inventory.
(5) The principle of convenient operation.
In addition, we also need to consider the production speed, the weight of the goods, sliding plates, explosion or freezing conditions, and other factors of change. Some factors can change the final choice.
Shrink wraps are usually used for irregularly shaped goods; goods that require long-term outdoor storage or environmental conditions that require waterproof; goods like the engine body need to be securely fixed on pallets, only shrink-wrapped packaging can be well suited to this Category; shrink-wrap package can be completely waterproof; in addition there are shrink films resistant to solar ultraviolet radiation available.
Stretch-wrapped goods have a wide range of applications, such as bags, boxes, bottles, cans, neatly arranged goods, metal tensile materials, rolled materials, plates, agricultural products, and instrument equipment.
In general, due to the difference in energy consumption, many freight forwarders are the first to consider stretching, and then consider retractable packaging when necessary.
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