Odour Nuisance

Question:

 

Telephone enquiry from the safety representative of a customer purchasing shrink covers:

Company employees asked the question of whether the smell of the shrink covers and the smell generated during pallet shrinking poses a health hazard.

 

Answer:

 

Dear Mr S,

 

We refer to your telephone call this morning. Along with other thermoplastics - e.g. polypropylene - polyethylene is a polyolefin. Ethylene, the basic component of polyethylene, is the olefin with the simplest structure:

 

H    H

|     |

C = C

|     |

H    H

 

In polymerisation, the ethylene molecules are bonded together (thus the designations polyethylene). This results in the formation of long, chain-like macromolecules from equal components. Polymerisation can be seen as a type of cooking process in a pressure cooker. Under heat and pressure, the C = C double bond is broken and can therefore link up to another molecule.

 

The polyethylene molecules contain branches. Both the level of molecule chain branching and the length of the side chains have a significant effect on the properties of the polyethylene.

 

These molecule chains are "broken" under the influence of oxygen and light, the polyethylene disintegrates and dissolves into its base materials - hydrogen and carbon. This process begins immediately, although it only becomes visible to our eyes after approx. 1 year, depending on solar intensity. Therefore, polyethylene is environmentally friendly, as no residues, gases, or other residues are generated. The primary product of all polyethylene films ( polyethylene exists as HDPE and LDPE. The difference can be seen and felt on numbers 2 and 4 in the recyclying symbol) is polyethylene granulate, which can be purchased from large chemical firms such as BASF or Degussa-Hüls.

 

This granulate is melted down in extrudes (an extruder is like a large, heated mincer). This liquid is then blown over a large blow head like a gum bubble, cooled and merged via rollers into a film hose. The film hose is wound into large rolls and further processed into other things including shrink covers.

 

During melting and the ensuing film blowing, a smell is generated, which may be likened to a burning stearin candle. This can be shown by lighting a piece of film and smelling the resulting smoke (caution: avoid allowing the melted polyethylene to drip onto skin or clothing, which results in painful burns). This smell dissipates relatively quickly and is completely harmless to health.

 

As the shrink covers you use are immediately put together and packaged, this smell has no opportunity whatsoever to dissipate. This is why there is an odour from the film when unfolding and covering the pallet. However, this smell dissipates relatively quickly and is not in any way transferred to the goods being packaged.

 

We hope these explanations reasonably meet your expectations. Should you have any further questions, please let us know. We are happy to provide advice and information.

 

 
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