Our modern high-tech world is no longer imaginable without transparent products. We are so used to their “invisibility” that we only notice them if defects diminish their transparency, and consequently, their final usage. If due to varying quality of the packaging film the same chocolates appear different on the shelf, the nice holiday photos appear hazy on the smart phone, or the motorcycle helmet’s face shield easily gets scratched – then, all of this will affect our quality expectation and can even become a hazardous risk.
The perceived quality of transparent materials is dependent on its transparency, gloss and color. The human eye can recognize very fine variations in sharpness, contrast and appearance of a show window or transparent packaging film when goods are displayed behind it. Quality variations of the transparent product diminish the perceived appearance of the product. Therefore, a high and consistent transmission quality is a key factor in the sales decision. Depending on the end-use, a long lifetime in regards to non-yellowing, scratch resistance, and gloss stability is required.
Each application asks for specific material properties and processing parameters. More than hundred different polymers are available for transparent end-uses. Many products consist of several components or multiple layers to combine different properties into one final, highly customized product. Besides the material selection, several production parameters influence the appearance and need to be optimized. Consistent transparency can only be guaranteed if the material and process factors are under control over the complete supply chain.
Visual perception is influenced by our individual preferences, which are dependent on personal factors like mood and age, environment (lighting, surrounding etc.), as well as our limited ability to communicate appearance differences. In order to guarantee consistent transparency under all possible situations, it is essential to define numerical parameters with customer relevant tolerances, which can be controlled in daily production and communicated among the entire supply chain of raw material and final product suppliers. A high quality production process should only be based on figures and facts and not emotions.
Photo Courtesy of BYK-Gardner.
