What is LDPE (film)?

LDPE stands for Low Density PolyEthene. Many users and producers still use the term ethylene instead of ethylene.

Polythene is made by polymerisation of ethylene (poly means "many"; so in fact it says many-ethene). Ethylene is obtained by cracking a light derivative of petroleum, such as naphtha.

The low density is obtained by running the polymerisation process under high pressure. This creates molecules with many side branches. The side branches ensure that the degree of crystallisation remains relatively low. Or in other words, molecules cannot lie well organised in or on top of each other due to their irregular shape, so fewer of them fit in a given space. The lower the degree of crystallisation, the lower the density of a material.

In everyday life, you can see this effect well with water and ice, for example. Ice is water in its (higher) crystallised state, and therefore much lighter than water (melted ice).

LDPE is a type of thermoplastic. This is a plastic that softens when heated, unlike rubber, for example. This makes thermoplastics suitable for reuse. After heating, it can be made into other desired shapes.

Advantages of LDPE (film)

LDPE is a tough plastic (has many side branches in its molecular structure) which is quite soft to the touch yet very strong. In addition, it is water-repellent, well-insulating and resistant to acids. LDPE-film is therefore very suitable as a packaging material. The film may also come into contact with food and can therefore be used in the food industry.

Due to its molecular structure, LDPE is suitable for shrink films. All types of PE shrink when heated in the longitudinal direction of the film. However, the side branches cause the film can also shrink in the width direction.

A major advantage of LDPE-film is that little material is needed to make packaging. As a result, relatively little energy is needed for production. It also creates fewer CO2 emissions than other packaging materials because it is so light and low in volume.

Another big advantage is that the material is easy to recycle.

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