**Guide**

The color transfer fastness of finished products at the splicing point needs to be tested according to the GB/T 31127-2014 standard, i.e., "Textiles — Tests for colour fastness — Colour fastness to splicing dye transfer".

**1. Requirements for Colour Fastness to Splicing Dye Transfer Grade**

**Requirements**

(Table/Image Placeholder)

**2. Differences from Previous Version Requirements**

Among the physical and chemical property testing items for garments, colour fastness to washing, dry cleaning, rubbing, perspiration, saliva, water, and artificial light are all relatively basic test items.

Referring to the indicator value settings of numerous garment product standards such as GB 18401-2010, GB 31701-2015, GB/T 14272-2021, GB/T 2660-2017, FZ/T 81006-2017, FZ/T 81007-2012, combined with rich testing data from recent years and the long-term implementation status of GB/T 21295-2014, the assessment indicators for colour fastness to washing, dry cleaning, rubbing, perspiration, saliva, water, and artificial light will continue to use the indicator values from GB/T 21295-2014. Furthermore, the colour fastness items from the original Table 1 and the original Table 3 are merged into one table (Table 1), listing the specific indicator values. Notably, for colour fastness to washing, a remark has been added: "Products marked as non-washable in the care instructions are not assessed."

**3. Test Principle and Scope**

**1. Scope of Test**

This standard describes two methods for testing the colour fastness at the splicing point of textiles: the washing method and the soaking method. It is mainly applicable to textiles assembled by splicing dark and light colored fabrics. Non-spliced textiles may also refer to this method.

**2. Test Principle**

2.1. **Washing Method (using a colour fastness to washing tester)**

    Place the specimen in a specified washing liquor and subject it to mechanical agitation under specified conditions of liquor ratio, time, and temperature. Subsequently, rinse and dry the specimen. Finally, assess the staining of the specimen using the grey scale for assessing staining or an instrument.

2.2. **Soaking Method (using a colour fastness to perspiration tester)**

    Place the specimen in a specified washing liquor. After relevant treatment, place it between two flat plates in the test device under a specified pressure. Subsequently, rinse and dry the specimen. Finally, assess the staining of the specimen using the grey scale for assessing staining or an instrument.

**4. Apparatus and Consumables Used**

The instruments and consumables used are listed in the table below:

(Table/Image Placeholder)

**5. Sampling**

Cut one specimen, approximately 100 mm × 40 mm (with a permissible tolerance of ±2 mm), from each of the two fabric samples to be spliced. Then, place these two specimens with their right sides together and sew them together along one of the short sides to form a combined specimen. If the finished product is already sewn and does not affect the pressure requirements of the test method on the specimen, this combined sample can be cut directly from the spliced area.

**6. Procedure**

**1. Method A – Washing Method**

1.1. Weigh 4 g of ECE reference detergent using a balance, prepare 1 L of washing liquor with Grade 3 water, and preheat it to (40 ± 2)°C for use.

    Place the combined specimen and the preheated washing liquor into a wash container according to a liquor ratio of 50:1. Load the container into Test Apparatus A (colour fastness to washing tester) and run for 30 minutes at a temperature of (40 ± 2)°C.

    Note: Other test temperatures may be used upon agreement between the interested parties, but this must be stated in the test report.

1.2. After washing, remove the combined specimen, rinse it thoroughly with running water, then squeeze out excess water. Finally, absorb excess moisture using filter paper.

1.3. Use a clip to hold the unsewn end of the dark-colored specimen and hang it to dry in air at a temperature not exceeding 60°C.

1.4. Assess the staining on the light-colored specimen using the grey scale for staining (GB/T 251) or an instrument.

**2. Method B – Soaking Method**

2.1. Weigh 4 g of ECE reference detergent using a balance, prepare 1 L of solution with Grade 3 water, and cool it to room temperature.

2.2. Place one combined specimen flat in a flat-bottomed container. Inject the solution prepared in 2.1 to wet it completely, maintaining a liquor ratio of 50:1. Leave it at room temperature for 30 minutes, occasionally pressing and moving the specimen to ensure the test solution penetrates the specimen fully and uniformly. Remove the specimen, discard the residual liquid, and use two glass rods to remove excess test solution from the combined specimen.

2.3. Place the combined specimen flat between two glass or acrylic resin plates in Test Apparatus B (colour fastness to perspiration tester), ensuring the specimen is under vertical pressure of (12.5 ± 0.9) kPa.

    Note: Each test apparatus can hold a maximum of 10 combined specimens simultaneously for testing, with each specimen separated by one plate (using 11 plates total). If fewer than 10 specimens are used, still use 11 plates to maintain the nominal pressure unchanged.

2.4. Place Test Apparatus B (colour fastness to perspiration tester) containing the combined specimens into a constant temperature oven (perspiration fastness oven) at a temperature of (37 ± 2)°C for 4 hours, with the combined specimens placed horizontally.

2.5. After soaking, remove the combined specimen, rinse it thoroughly with running water, then squeeze out excess water. Finally, absorb excess moisture using filter paper.

2.6. Use a clip to hold the unsewn end of the dark-colored specimen and hang it to dry in air at a temperature not exceeding 60°C.

2.7. Assess the staining on the light-colored specimen using the grey scale for staining (GB/T 251) or an instrument.

Note: Generally, the staining grade from the soaking method test is much more severe than that from the washing method.

**7. Analysis of Staining Causes and Prevention**

**1. Analysis of Causes for Splicing Dye Transfer**

1.1. Staining on light-colored fabric is mainly caused by color fading from the dark-colored fabric. If the dark-colored fabric itself has poor fastness, or if inappropriate processes and auxiliaries are used, it can easily lead to staining of the solution during washing. The light-colored fabric then absorbs the stained solution, causing cross-staining.

1.2. If the fabric is stretch fabric, spandex does not dye easily and tends to have surface-adsorbed dye. If the reduction clearing is insufficient, it can also lead to cross-staining between fabrics.

1.3. If the dark and light fabrics are made of the same fiber component, cross-staining between the shades can also occur, especially with polyester fabric. This phenomenon is particularly noticeable and is caused by their mutual chemical interaction. This is not necessarily a problem with the fabric's colour fastness, but a defect arising from the garment's design.

**2. Preventive Measures in Daily Life**

2.1. For solid-colored garments, it is recommended to wash dark and light colored clothes separately, and the soaking time should not be too long, approximately 5-10 minutes.

2.2. Choose neutral detergents; try to avoid alkaline detergents, as alkaline detergents can cause hydrolysis of certain dyes.

2.3. The color change and staining of multi-colored garments are also affected by factors such as soaking time, storage conditions, improper washing, and inadequate drying. The GB/T 31127-2014 standard "Textiles — Tests for colour fastness — Colour fastness to splicing dye transfer" does not explicitly specify under which circumstances to choose which test method. Therefore, when selecting this standard to test the splicing dye transfer fastness of assembled garments, enterprises should choose based on the requirements of their own products in conjunction with relevant considerations.

Note: This article is reproduced from the "Yunxiang Testing Service" platform!