Colour and Haze Are Important Parameters for Product Appearance. If a Products Colour Or

Abstract

Colour and haze are important parameters for product appearance. If a products colour or haze is off-specification, it cannot be sold or needs to be reworked (if possible). The Pt/Co colour and haze of samples is currently determined by means of analysis with the HunterLab UltraScan VIS colorimeter in the laboratory of Hexion. The analysis of colour and haze, applying an in-line analyser, would allow better monitoring of these parameters during process. This could improve insight in production and allow the ability to intervene in time in the case of possible upsets. The main focus for the project are the products acquired in the Versatics business. The availability of different in-line analysers was studied and they were reviewed based on certain critical to quality parameters. Two in-line instruments, Optek AF26 colour sensor and Sigrist ColorPlus, were selected and acquired for testing in the laboratory. In addition, a mini-spectrophotometer, StellarNet BlackComet capable of CIE L*a*b* colour measurements, was included in the testing. A series of Pt/Co colour standards were measured and applied for calibration followed by the measurement of various Versatic Acid and Cardura samples. The robustness of the instruments, according to stability, temperature and turbulence, was reviewed. The instruments were validated and compared according to the selected statistical parameters. The testing demonstrated that the measurement of colour and haze using in-line instruments offered good possibilities. The Optek test instrument showed comparable sample results in relation to the reference instrument while the Sigrist test analyser demonstrated different sample results in comparison to the reference instrument. The instruments use a different measurement principle and accommodate different optical path lengths. A longer optical path length proved more precise measurements during analysis of low Pt/Co colour. The rental Optek AF26 40mm optical path length in-line analyser confirmed the most comparable and reasonable results according to the calibration, sample measurement and validation. The analyser demonstrated better repeatability, reproducibility and limit of detection in contrast to the reference instrument. In addition, the results acquired with the Optek 40mm analyser were comparable to an absolute value (certified reference standard). The in-line analyser appeared suitable for the in-line measurement of Pt/Co colour and haze during production process in the Versatic Acid and Cardura plants with potential leverage to other production facilities.