Contrast of Test Methods of Textile Color Fastness to Washing

Color Fastness to washing is one of common test items of textile dyeing fastness, mainly testing the color dyeing fastness of textile fabrics for garment and home textile products after one or more simulations of household and commercial washing. The common test standards are GB/T 3921-2008 and ISO 105 C10: 2006 and AATCC 61: 2010. therefore, it is of practical significance to compare the three standards.

The test method is to stitch specimen and standard adjacent fabric, and after washing, cleaning and drying, put specimen into the condition of suitable temperature, alkali concentration, bleaching, and friction and then clean it, so as to obtain test result at a shorter time. The friction of this period is achieving through the rolling and collision of small liquor ratio and an appropriate number of stainless steel balls. Take out the specimen, assess the color change degree of specimen by using the Gray Scale for Color Change, and assess the staining degree (grade) of adjacent fabric by using the Gray Scale for Staining, where Grade 1 is the worst, Grade 5 is the best. From washing temperature, detergent, preparation for cloth sample, adjacent fabric and other aspects, the paper compared the three standards, carried out the test on the same fabric, using different standards and the contrast the test results.

The Contrast of Standards for Color Fastness to Washing

1 Dimension of Specimen

For the dimension of a specimen to be tested, there is an obvious difference between AATCC 61:2010, GB/T 3921 – 2008 and ISO 105 C10: 2006. The dimensions of a specimen to be tested of three standards are as shown in Table 1. From Table 1, it can be seen that the dimension of a specimen to be tested of AATCC 61:2010 is generally be determined according to washing ways of a garment. If hand washing of 40℃ is chosen, the dimension of the specimen to be tested is 5 cm × 15 cm. Generally, the washing way is chosen by clients; or an inspection organization conducts the tests according to optional washing ways. Whatever the washing way is, the dimension of the specimen to be tested of GB/T 3921 – 2008 and ISO 105 C10: 2006 is 4 cm × 10 cm.

Table 1: The Dimension of Sample of Color Fastness of AATCC 61, GB/T 3921 – 2008 and ISO 105 C10

2 Types and Usage of Adjacent Fabric

In the test of Color Fastness to washing, AATCC 61:2010 mostly adopts multifiber adjacent fabric, and ISO 105 C10: 2006 generally adopts multifiber adjacent fabric too, but if clients require, it is able to use single fiber adjacent fabric. GB/T 3921 – 2008 generally adopts single fiber adjacent fabric, but now adopts multifiber adjacent fabric too and the adjacent fabric is equivalent to ISO 105 C10: 2006. The adjacent fabric component of the three standards sees Table 2 for details.

Table 2: Contrast of Adjacent Methods of AATCC 61:2010, GB/T 3921 – 2008 and ISO 105 C10: 2006

3 Washing Requirement and Washing Parameters

In the color fastness to washing test, AATCC 61:2010 has five different items. So do ISO 105 C10: 2006 and GB/T 3921 – 2008. Three standards have something in common that clients are allowed to select the item, besides, these five items can be tested by the third party inspection company by using the material offered by clients and then select test result. Take the best item as Care Label recommendation. The difference between the three lies in the five items of ISO 105 C10: 2006 are as the same as that of GB/T 3921 – 2008, where there are Method 1, Method 2, Method 3, Method 4, and Method 5. While AATCC 61:2010 is different. The difference of washing parameters of the three standards, ISO 105 C10: 2006, AATCC 61:2010 and GB/T 3921 – 2008 mainly is that factors like the component of detergent, temperature, the number of steel balls and time are different. Washing parameters of AATCC 61:2010 see Table 3 for details. Washing parameters of ISO 105 C10: 2006/GB/T 3921 – 2008 see Table 4 for details.

Table 3: Washing Parameters of AATCC 61:2010

                         Note: Do only when the client specifically designates and require to do 4A, 5A standard.

From Table 3 and Table 4, it can be seen that detergent of AATCC 61:2010 mainly are AATCC standard reference detergent WOB (without fluorescent whitening agent), bleached agent sodium hypochlorite, anhydrous sodium carbonate, and deionized water; detergent of ISO 105 C10: 2006/GB/T 3921 – 2008 are mainly soap, anhydrous sodium carbonate, and Ⅲ grade water. On the temperature, AATCC 61:2010 has two kinds of temperature, while both ISO 105 C10: 2006 and GB/T 3921 – 2008 have one kind of temperature. There is no great difference between their solution volumes. The number of steel balls of AATCC 61:2010 is much more than that of ISO 105 C10: 2006/GB/T 3921 – 2008. Washing times of AATCC 61:2010 are the same, while washing times of ISO 105 C10: 2006 and GB/T 3921 – 2008 will be changed according to the items.

Concerning with the washing method, the requirements of AATCC 61:2010 is that firstly preheat the standard detergent WOB (without fluorescent whitening agent) and steel balls to the washing temperature needed while washing, and then wash the combination specimen according to the parameters in Table 3; after washing , bleach it with water of 40℃ for three times, and every time takes 1 min; after then, dry it in the environment of not more than 60℃. For ISO 105 C10: 2006 and GB/T 3921 – 2008, firstly preheat the soap washing liquid to the washing temperature needed, and then clean the combination specimen according to the parameters in Table 4; after washing, bleach it with cold water for 2 min and then dry it in the environment of not more than 60℃. The three standards have something in common that dry the combination specimen in the environment of not more than 60℃ and preheat the detergent before washing. The differences between the three are that in AATCC 61:2010 needs preheating the steel balls while in ISO 105 C10: 2006 and GB/T 3921 – 2008 needn’t.

4 Gray Scale for Color Change/ Staining

AATCC 61:2010, ISO 105 C10: 2006 and GB/T 3921 – 2008 all adopt the same Gray Scale for Color Change/ Staining to assess the color fastness grade because of adopting the specified colorimetry statistics standard to assess the Gray Scale for Color Assessment. The Gray Scale for Color Assessment is divided into Grade 1- Grade 5, half grade increasing progressively, and packed into a bag. When using the Gray Scale for Color Assessment, there will be 6 results turning up owing to the staining test have 6 fiber stripes participating in an inspection. If only have to assess one staining result, so take the worst result on the six fiber stripes of three standards as the staining result.

Table 4: Washing Parameters of ISO 105 C10: 2006 and GB/T 3921 – 2008

Tests Analysis and Results Analysis

1 Test Method: According to GB/T 3921-2008, ISO 105 C10: 2006 and  AATCC 61: 2010, separately test color fastness to washing of specimen.

2 Related Apparatus:
Balance: accurate to 0.01g
TF418 – Color Fastness to Washing Tester (Launderometer)
TU300 – Color Light Box

3 The principles of the three test standards are basically the same, but the testing conditions are different. ISO 105 C10: 2006 and GB/T 3921 – 2008 adopt the same test methods. The great difference between AATCC 61:2010 and ISO 105 C10: 2006 / GB/T 3921 – 2008 lies in the detergent in washing condition and in whether steel balls are added or not. There is difference between test results of the same fabric under three test standards. For adjacent fabric, although the adjacent fabric of ISO 105 C10: 2006 and GB/T 3921 – 2008 is DW multifiber adjacent fabric, and that of AATCC 61:2010 is No.10 multifiber adjacent fabric, the components of the six fiber stripes of these two kinds of adjacent fabric are the same. As a result, mainly contrast the effect of test methods of different standards on specimen to be tested. The experimental statistics show that using the same test sample and adjacent fabric if using the methods to AATCC 61:2010, color change will be slightly serious, and if use the methods of ISO 105 C10: 2006 / GB/T 3921 – 2008 to inspect, staining is slightly serious.