In the production process, in order to ensure the quality stability of resin products, it is generally controlled by measuring acid value or viscosity. After the resin is synthesized and diluted, quality inspection should be carried out before discharging into the dilution tank. Measures should be taken to adjust the unqualified indicators. In order to ensure the quality of finished products, it is not only required that all test indicators are qualified, but also that the performance indicators between batches of products are stable. The measurement indicators include color (including appearance and chromaticity), viscosity, acid value, gelation time (25 ℃ or 82 ℃), storage period (80 ℃), etc. After passing the final inspection, it can be packaged, stored, or shipped out of the factory. If there are special needs, further testing of other projects can be carried out. The specific measurement methods are introduced as follows.

1. Appearance and Transparency

Pour the resin to be tested into a clean colorless glass test tube, at a height of approximately 10-15mm, and visually inspect the appearance and transparency of the resin in a well lit room.

2. Color

The color of resin is influenced by many factors, such as the type and purity of resin, the temperature and time of polymerization reaction, and the cleanliness of equipment systems. The final color of the resin can change from clear and colorless to dark amber. Controlling the color of resin is useful for maintaining the uniformity of resin production quality and is also an indicator of product quality.

There are several methods for measuring the color of resin: Firstly, the Gardner Hellige colorimetric method can be used for color measurement in production processes and product chromaticity measurement; The second is APPHA color measurement (American Public Health Association standard), mainly used for the color characteristic indicators of products. In addition, a three color colorimeter can be used to measure and calculate the brightness value, eliminating possible errors in visual evaluation, and obtaining a more accurate chromaticity.