Introduction
In the production and application of coatings, inks and coating materials, the hiding power is one of the key indicators to evaluate its performance, which reflects the ability of the material to mask the color of the substrate. Traditional coverage evaluation mostly relies on manual visual comparison of the coating film on the masking force jam, which is easily affected by ambient light and the subjective experience of the observer, and the results are inconsistent. With the development of detection technology, the combination of standard occlusion cardboard and spectrophotometer to realize the digital evaluation of occlusion force through quantitative chromatic aberration data has become an effective way to improve the accuracy and efficiency of detection. This paper aims to explore the principles, methods and practical value of this combined technology.
Principle overview
The essence of masking force is the degree to which the coating shields the color of the substrate, and its digital evaluation is based on the principles of color science. The spectrophotometer quantifies the color difference between the black and white areas by measuring the reflectance spectrum of the coating on the black and white areas of the standard masking force cardboard. When the color difference is less than the set threshold, the coating is considered to have adequately covered the substrate. This process transforms subjective visual judgments into objective data, reducing human interference. The basic formula can be expressed as: ΔE = √ (ΔL² + Δa² + Δb²), where ΔE is the total chromatic aberration, and ΔL, Δa, and Δb represent the difference between brightness and chromaticity, respectively.
Combined method
Conjugation operations need to follow a standardized process. First, choose a coverage jam that meets industry standards, and its black and white areas should have clear boundaries and stable reflection characteristics. Subsequently, the material to be tested is evenly coated on the cardboard to form a wet film of the specified thickness and dried under standard conditions. The chromaticity values of the black and white areas covered by the coating are measured separately using a spectrophotometer, and the average value of each area needs to be measured at multiple points to ensure representativeness. Finally, the excellent ΔE is calculated by the built-in software or external of the instrument, and compared with the preset standard to determine whether the masking force is up to standard. This method is suitable for rapid testing in laboratories and production lines.
Technical advantages
Digital assessment has many advantages over traditional visual methods. In terms of repeatability, instrument measurement avoids visual differences and results fluctuate little. In terms of accuracy, spectrophotometers can capture subtle chromatic aberrations and are more sensitive than the human eye; In terms of efficiency, automated measurement and data processing shorten inspection cycles. In addition, data traceability is enhanced, making it easy to establish long-term quality files. This technology provides a reliable basis for material research and development and quality control.
Application considerations
There are several key points to pay attention to in practical application. Environmental conditions such as temperature and humidity may affect the dryness and color performance of the coating, so it is recommended to operate in a standard environment. Instrument calibration should be performed regularly to ensure consistent measurement datums. For different material types, it may be necessary to adjust the chromatic aberration threshold to accommodate specific industry standards. Factors such as coating uniformity and jammed surface condition also need to be strictly controlled to avoid measurement deviations. By standardizing the operation process, the reliability of the evaluation results can be further improved.
Summary
The combination of coverage cardboard and spectrophotometer technology pushes the traditional coverage assessment to the digital stage, realizing the transformation from subjective judgment to objective quantification. This technology not only improves the accuracy and consistency of detection, but also promotes the standardization and data management of the production process. With the continuous improvement of relevant standards and the advancement of instrument technology, digital evaluation is expected to play an important role in more material testing fields and provide solid support for industry quality control.
References
1. Application of Color Measurement in Coating Performance Evaluation, Journal of Material Testing Technology, 2020.
2. Principles and Operating Specifications of Spectrophotometers, Instrument Analysis Manual, 2019.
3. Comparative Study of Coverage Test Standards, Coatings Industry, 2021.