HEAT SHRINK – HEAT SHRINK MATERIALS
Heat Shrink of plastic films is used lately more and more for the packaging of various products, from food to boats.
The Shrink Film or Shrink Wrap is made of a polymer plastic.
There are various categories of Shrink Film available in the market and the choice of the most suitable depends on various parameters such as the type of product to be packaged, the conditions during the packaging procedure but also on the specific requirements that we have for the final product. For example depending on durability, appearance, transparency etc., there are Shrink Film (Heat shrink), Polyolefin, PVC and others, that can be single-layered or multi-layered.
The technique of Heat Shrink is based on the plastic films' property and capability of shrinking and tightening on anything it covers after it is heated.
We can create a Shrink Film that shrinks on one dimension (one-way shrinking) or on both (bi-directional). The Films can be dilated when warm, and they direct the chains of their molecules depending on the direction they are dilated. If we then cool them, the Film maintains the characteristics it took during its heated condition (thickness, width). If we heat it again, it tends to take the dimensions it had during its' previous condition. Before the dilation, the chains of the Films' or Pipes' molecules have a random direction like watching a plate of wound, tangled up spaghetti. When we apply a force of pull we align and provide direction and orientation to the molecule chains. If we then cool them, the latter condition will remain. If we then re-heat them, the thermal energy allows the molecule chains to shrink and return to their original form. The family of Shrink Film has been extended during the last years to various multi-layer types of Film. Depending on the type of layers' plastic (PE.LD, PE.HD, PP, EVA, PVC etc.), we can give various characteristics and attributes to the final multi-layer Shrink Film.
The advantages of Heat Shrink as a method of packaging are many:
1) Can be easily integrated on a production line like an on line procedure, and as a result to achieve a flow of finished products up to their placement on the pallet.
2) It perfectly protects products from moisture, dust and other damages, and in some cases it can be even airtight.
3) It aids in the easier placement of products on the pallet and overall enhances the safe transport of the products to the consumer.
4) The cost of the packaged unit is extremely low.
