GB/T 27592-2023 in English

1. Background and significance of the standard

GB/T 27592-2023 "Determination of fixation rate of reactive dyes by pad dyeing" is an important standard for quantitative evaluation of the fixation efficiency of reactive dyes in the dyeing process of textiles. This standard replaces the old version GB/T27592-2011. The main revisions include adding term definitions, introducing the "soap boiling residue colorimetry method" and improving the test report requirements.

2. Comparison of standard frameworks

3. Interpretation of the core clauses of the standard

3.1 Definition and calculation of fixation rate

Fixation rate (degree of fixation) is a key indicator to measure the efficiency of dye fixation on fiber. The new standard provides two calculation methods:

• Method 1: based on the total feed amount
• Method 2: based on the amount of dye on the fabric before fixation

3.2 Pad dyeing process optimization

The new standard emphasizes the precise control of the pad dyeing process, including:

• Dye liquor concentration: 20 g/L
• Padding ratio: one dip and one pad
• Fixation conditions: select the optimal process according to the characteristics of the dye

4. Detailed explanation of the measurement method

4.1 Extraction method measurement steps

1. Pad dyeing:It is carried out in accordance with GB/T 2387-2013 and is divided into pre-drying fabric samples (Sample I) and fixing fabric samples (Sample II).
2. Solution preparation: Weigh 0.1g of each sample I and II, add sulfuric acid solution and shake to dissolve.
3. Absorbance determination: Use a spectrophotometer to measure the absorbance values A₁ and A₂ at the maximum absorption wavelength.
4. Calculation formula: Fixation rate F = (A₂m₁ / A₁m₂) × 100%

4.2 Soap boiling residual solution colorimetric method

1. Dye solution preparation: Weigh 0.5g~1g dye solution, dilute to an appropriate volume V₀, and measure the absorbance A₀ of the original solution.
2. Pad dyeing: Accurately weigh the mass of the cloth sample m and m₁, and perform fixation treatment.
3. Soap boiling: Soap with detergent MA solution at 95°C for 15 minutes, collect the rinse liquid and make up to volume V.
4. Absorbance measurement and calculation: Use the formula F = [1 - (AV m₀) / (A₀ V₀ (m₁ - m))] × 100%

5. Implementation suggestions