GB/T 21875-2016 in English

Analysis of standard formulation background and technological evolution

GB/T21875-2016 "Determination of dye lifting power" standard is to standardize the test methods of the dye industry and ensure the consistency and comparability of dyeing quality. This standard replaces the old version GB/T21875-2008, and has made major revisions to some of its contents, including:

• Delete the "Terms and Definitions" chapter
• Add a new "Principle" chapter
• Divide the instruments and materials into two chapters: Materials and Reagents, Instruments and Equipment
• Modify the determination method of the measurement point
• Add the dyeing method of reactive dyes for wool

Determination Principle and Procedure

The determination of dye lifting power is based on the relationship between dyeing depth and color depth value (Integ value). By dyeing different dyeing depths on a specific fabric, the color depth value at each depth is measured, and the lifting power curve is drawn.

The measurement steps include:

1. Determine the measurement point: Select the appropriate dyeing depth according to the dye type.
2. Dyeing operation: Prepare the dye bath according to the best dyeing method and perform dyeing and post-treatment.
3. Color depth value determination: Use a colorimeter to determine the Integ value of each dye sample.
4. Draw a curve: Draw the lifting force curve with the dyeing depth as the horizontal axis and the color depth value as the vertical axis.

Implementation suggestions and precautions

To ensure the effective implementation of the standard:

• Laboratory conditions: Equipped with laboratory hydraulic or pneumatic two-roller mill, colorimeter and other instruments and equipment.
• Operation specifications: Strictly follow the dyeing method and measurement steps specified in the standard to conduct the experiment.
• Data processing: The rounding value comparison method in GB/T8170-2008 is used to process the test results.
• Report requirements: The test report should include the name of the dye being tested, standard number, dyeing method, instrument model, fabric type and other information.