Definition and Measurement of Rubbing Color Fastness
- Rubbing Color Fastness
Rubbing color fastness refers to the ability to sustain original color of dyed fabrics when rubbing. Dry rubbing color fastness refers to the situation of fading and staining of dyed fabric when rubbed with a standard white cloth. Wet rubbing color fastness refers to the situation of fading and staining of dyed fabric when rubbed with a standard white cloth which water content is 95% to 105%. The evaluation of Rubbing color fastness depends on the degree of staining of white cloth. After testing, the white cloth is compared to staining sample cards to measure staining fastness. Rubbing color fastness, same as washing color fastness, divide into 5 grades and 9 files, among which grade 5 is the best and grade 1 is the worst. The friction fading of fabric is to make dye fall off caused by friction. Wet rubbing is influenced by both external force and water, so it is about one level lower than dry rubbing.
- Rubbing Color Fastness Test
- Preparation of Test Apparatus and Materials
Electronic Crockmeter (Figure 2), Gray Cards Evaluating Staining, Standard Cotton adjacent fabric (50mm*50mm uses to circular friction head; 25mm*100mm uses to rectangular friction head), Sample to be Tested
- Testing Method
If tested sample is fabric or carpet, you must prepare two groups of samples with no less than 50mm*200mm, and each group contains two samples. One group is the length direction of samples is paralleled to warp yarn, used to dry rubbing and wet rubbing in warp direction; the other is the longitudinal direction of samples is paralleled to weft yarn, used to dry rubbing and wet rubbing in weft direction.
If the sample is multicolor, you should choose sample’s position carefully and let every color rubbing. If the area of each color is large enough, you must take all samples.
If tested sample is yarn, you have to weave it as a fabric and ensure its size in no less than 50mm*200mm; or yarn is winded parallelly in a paperboard whose size is same as tested sample.
- Rubbing cloth should adopt cotton semi-finished fabrics which have been desized, scoured, bleached and do not contain any finishing agent.
- Tested sample is fixed on bottom floor of tester by clamping device, and its length direction is in accordance with movement direction of tester.
- Dry rubbing cloth is fixed on friction head of tester, and the warp direction of it is in accordance with movement direction of friction head.
- Press Start Switch, reciprocating rub for 10 times in 10s (reciprocating movement is 100mm, vertical pressure is 9N), then take the dry rubbing cloth off.
- Taking another rubbing cloth, and rolling it on rolling fluid device after soaked in cool water, to make moisture content controlled in 95% to 105%.
- To do the above operation of dry rubbing cloth repeatedly. When rubbing is finished, dry it at room temperature.
- Using gray cards evaluating staining to measure the staining fastness of above dry and wet rubbing cloths.
Definition and Measurement of Perspiration Fastness
1. Perspiration Fastness
Perspiration fastness refers to the ability not to fade and not to stain when dyed fabric is perspired. People’s sweat consists of complicate composition, and its main composition is salt. Sweat is divided into acidity and basicity due to difference of people. Textiles contact long with sweat has a large impact on some dyes. Perspiration fastness test is to use artificial perspiration with different acid and alkaline to imitate the sweat situation when human wear textiles, then test the textiles. The machine using to test perspiration fastness is perspiration fastness tester. When testing, textiles sample sewing together with adjacent fabric, is soaked in artificial perspiration, then remove excess liquid; and handle it under specified pressure, temperature, time in tester; next dry sample and adjacent sample respectively; last use gray cards to evaluate discoloration of original sample and staining of adjacent sample.
2. Perspiration Fastness Test
- Preparation of Test Apparatus and Materials
Perspiration Fastness Tester (Figure 3), Stained Cup (200mL), Gray Cards evaluating discoloration, Stained Cards, Sodium Chloride (C.P.), Sodium Hydroxide (C.P.), Sodium Dihydrogen Phosphate Dihydrate (C.P.), Disodium Hydrogen Phosphate Dodecahydrate (C.P.) or Disodium Hydrogen Phosphate Dihydrate (C.P.), L-histidine hydrochloride-hydrate (C.P.), Multi-fiber adjacent fabric or single fiber adjacent fabric, Sample to be Tested.
- Testing Method
1. Sample Preparation
Same as washing fastness test. Choices of standard single fiber adjacent cloth are seen in Table 4.
Table 4 Choices of Standard Single Fiber Adjacent Cloth
|First Piece||Second Piece||First Piece||Second Piece|
|Wool||Cotton||Vinegar Fiber||Sticky Fiber|
|Silk||Cotton||Polyamide Fiber||Wool/Sticky Fiber|
|Linen||Wool||Polyester, Polyacrylonitrile Fiber||Wool/Cotton|
2. Operating Procedure
- To make up artificial perspiration as request of Table 5, and do acidity and basicity perspiration fastness test respectively.
Table 5 Artificial Perspiration Configuration Table
|Acid Liquid(g/L)||Alkaline Liquid(g/L)|
(C_6 H_9 O_2 N_3∙HCl∙H_2 O)
|Sodium Chloride (NaCl)||5||5|
|Disodium Hydrogen Phosphate Dodecahydrate (Na_2 HPO_4∙12H_2 O) or Disodium Hydrogen Phosphate Dihydrate |
(Na_2 HPO_4∙2H_2 O)
|---||5 or 2.5|
|Sodium Dihydrogen Phosphate Dihydrate (Na_2 H_2 PO_4∙2H_2 O)||2.2||---|
|0.1 mol/L Sodium Hydroxide (NaOH), adjust PH||5.5||8.0|
- To prepare two combined samples as prescribed requests, and weigh; take acid liquid and alkaline liquid as bath rate at 1:50.
- To put two combined sample into acid liquid and alkaline liquid respectively, soak them completely, then place them at room temperature for 30min.
- Take combined sample out, and use two glass rods to remove excess liquid of it; then place it on sample board, use the other sample board to scrape excess liquid, and place in between two sample board, adding pressure of 12.5kPa and maintain. Using the same method to place another combined sample, but the apparatus of acid liquid and alkaline liquid test should be separate used.
- To place the apparatus with acid and alkaline sample in temperature chamber of 37℃±2℃ for 4 hours.
- Take apart suture of combined sample but keep one short edge, unfold it, and drape and dry it in air with no more than 60℃.
- Use gray cards to evaluate discoloration of original sample and staining of adjacent cloth.