HIRSCH 4th story

Type 1 Pilot Action:
Hirsch AG – Evaluation of UV tests of biopolymers

Goal: Hirsch is developing a new material for their leather bracelets. To improve sustainability the new material is a biopolymer. During standard UV exposure tests, visible changes of the surface appear in form of an oily film. This film shall be investigated and classified.

Approach: Hirsch provided samples before and after UV exposure. The already visible differences were enhanced in microscopic images. Raman spectroscopy was used to identify the film on the surface. Standard surface measurements did not show differences of the samples. In thorough depth measurements the spectra changed when going through the film. NMR measurements at KI were done additionally for further analysis.

Results: Both measurement methods showed differences of the UV exposed sample to the natural one. Results are shown in Figure 1 and both showed the same behaviour. UV exposure causes a decrease of the amount of double bonds and an increase of ester groups.

Company Statement: The results suggest diffusion of a softening agent from the material additives of the polymer mixture will be adapted.

Involved Partners: CTR/SAL, KI