Plastic plaques are produced for a variety of purposes and serve an essential role in the development and evaluation of plastic products. On their most basic level, plastic plaques act as samples that allow manufacturers to see what their formulation will look like and how it will behave in its final form. The color of polymer pellets cannot be used to predict finished product appearance, as texture, gloss, and degree of translucence all impact color perception. Additionally, plastic extrusion and molding processes create heat, which causes plastic to take on a slightly more yellow appearance. Rather than going through the time and expense of a full manufacturing cycle, plaques make it possible to quickly create a variety of samples for aesthetic and utilitarian assessment. Spectral analysis of these plaques is an essential part of plastics manufacturing and research, facilitating polymer design and production in an economical and efficient fashion.
Evaluating Plastics Spectrally
Spectrophotometers are an instrumental part of evaluating plaques to ensure accurate pigmentation based on an existing standard or to create a new color standard for future products. The versatile nature of spectrophotometric analysis and technology allows for precise measurement of opaque, translucent, and transparent plastics while accounting for variables such as texture and reflectance.1 Aside from quantification of immediate color, spectrophotometers can be used to measure additional factors affecting the optics and performance of plastics:
Haze Measurement: Haze refers to the clarity of plastics. Haze measurements allow plastic manufacturers to evaluate the specific level of transparency or translucence of a product and modify their formulation to reach their desired clarity.
Yellowness Index: Over time, degradation of plastics often leads to yellowing as the result of light exposure. Spectrophotometric Yellowness Index testing allows plastics manufacturers to assess their product’s susceptibility to this process and test the effectiveness of formulations designed to withstand yellowing.
Whiteness Index: There are multiple whiteness indexes that allow for precise measurement of white hues. Spectrophotometric analysis allows you to quantify the whiteness of plastics according to the standard that is most appropriate for your purposes.
Troubleshooting with Plaques
Once a product is in production, spectrophotometric analysis of plaques may be used to troubleshoot the manufacturing process should color inconsistencies arise. If masterbatch issues are suspected, for example:
[T]he testing for the actual dosage of masterbatch forms a major part of the investigation into complaints or other notifications of deficiencies. A tried and trusted method is the production of test plaques with both the recommended dosage and the suspected deviation from this. Colorimetric comparison to the suspect product can often provide a useful basis for identifying the cause of the problem.2
Objective spectral data allows plastics manufacturers to pinpoint problems and quickly evaluate corrective measures to optimize production. By combining the ease of plaques with the rapid, accurate analysis of spectrophotometers, you can significantly enhance efficiency to save both time and money.
Spectrophotometric Analysis of Plastic Plaques in Practice
Spectrophotometric analysis of plaques plays an important role in researching how plastics respond to particular stressors, providing important information for manufacturers and users of plastic products. For example, the clarity of plastic medical devices is critical to healthcare providers and patients ensuring that practitioners are able to observe fluid levels and color, bubble, and clot formation, and detect contaminants. However, routine sterilization procedures can lead to discoloration, potentially preventing clinicians from accurately assessing a patient’s condition while also having a negative psychological impact on both care providers and patients. In order to assess the effect of sterilization processes on various types of polymer, researchers created plaques using a range of plastics, the color of which was measured using a HunterLab spherical spectrophotometer.3 The plaques were then exposed to either gamma or E-beam radiation to simulate sterilization conditions and re-measured at set intervals to determine both immediate and long-term color change. The precise color assessment made possible by spectrophotometric instrumentation allowed for quantifiable comparison of sterilization method effects on plastics. When the final data was available, TABS, acrylic, and PC all showed significant discoloration after exposure to gamma and E-beam radiation. Copolyesters, however, had “the lowest shift of any of the materials examined,” and are recommended for use in medical environments employing radiation-based sterilization methods. This is just one example of how spectral analysis contributes to knowledge and practices in a range of industries and can have a very real effect on consumer choice of plastics.
The HunterLab Difference
HunterLab’s diverse range of spectrophotometric instruments is ideal for spectral analysis of plastics. Whether you’re working with transparent, translucent, or opaque polymers, textured or smooth, glossy or matte, we have the tools you need for accurate color and haze measurement. For over 60 years, our ingenuity, innovation, and expertise have made us the leader in the field of spectrophotometric analysis. Contact us today to see how our technologies and outstanding customer support can meet the needs of your business.
- “On the Relations Between Color, Gloss, and Surface Texture in Injection-Molded Plastics,” August 2009, http://www.researchgate.net/publication/230105142_On_the_relations_between_color_gloss_and_surface_texture_in_injectionmolded_plastics ↩
- “When the Color Doesn’t Match,” April 12, 2012, http://www.grafe.com/en/aktuelles/presse/press-review/246-when-the-color-doesn-t-match ↩
- “Where Color Meets Clarity,” July 1, 2010, http://www.mddionline.com/article/color-clarity ↩