Modification of film properties

Problem

The current film does not have the capacity to protect the packaged product from the light to which it is subjected.

Objective

Improve the light filtering properties of the current film. To this end, the following specific objectives were addressed:

• Know the wavelength of the light that is damaging the product
• Select additives and pigments to incorporate into the polymer
• Manufacture film prototypes
• Study the improvement obtained

ATRIA Solution

Firstly, the spectrum of light that the current film, made of low-density polyethylene, is capable of filtering was studied. The objective of this study was to determine the wavelengths that pass through the material and damage the packaged product.

Based on this information, various additives and pigments were selected to be incorporated into low-density polyethylene in order to improve its light-filtering properties. In the case of the additives, their function was aimed at improving the filtering of the ultraviolet range, while the pigments focused on improving the filtering of visible light.

To incorporate the additives and pigments into the low-density polyethylene, a double-thread extruder was used, with which different masterbatch (granules) could be prepared for each of the proposed solutions. Both the concentration of additive and pigment incorporated as well as the combination of both solutions were studied.Next, using a semi-industrial blower, 10 meters of prototype film were prepared with each of the solutions proposed in each masterbatch. During the manufacturing process of the films, the thickness was optimized, to adjust it to that of the current film, and the width.

Finally, tests were carried out to characterize the improvement of light filtering in the prototype films with respect to the reference film (current polyethylene). In addition, the color variation of the film and other specific customer requirements were characterized.