Fastness Testing.pptx

Colour fastness, Light fastness, Rubbing fastness

1. Fastness Testing

2. Color fastness of a dyed material: Color fastness, in normal sense, refers to the resistance of color of a dyed or printed textile to various types of influences (e.g. water, light rubbing etc.) to which they are normally exposed in textile manufacturing and in practical sense. So we can say color fastness is the resistance of the color to fade or bleed by some agencies like washing, light, water, chlorine, perspiration, ironing etc. Color fastness is usually assessed separately with respect to: 1. Changes in the color of the specimen being tested, that is color fading ; 2. Staining of undyed material which is in contact with the specimen during the test, that is bleeding of color .

3. Dyed or printed material may lose its color for the following: Due to decomposition of dye molecules in the fibre (as in light fading ) Due to their removal (bleeding) into the external medium (as in washing ) Due to reaction with acid, alkali or perspiration(as in perspiration fastness) Due to friction of outer surface (as in rubbing )

4. Grey scale: Grey scale is an empirical scale containing a series of pairs of neutrally colored chips, showing increasing contrast within pairs. It is used visually to assess contrasts between the pairs of patterns. For example, in order to give numerical assessment of color changing and staining two sets of standard grey scales are used. The ISO grey scales have two series of chips against which the change of color of a specimen and that of staining of adjacent uncolored specimen can visually assessed and rated on a 1-5 scale. Two sets of standard grey scales are used to assess color fastness. One for assessing change in color Other for staining.

5. 1. Color change grey scale: These scales consist of 5 pairs of grey colored materials rated from 1-5. Number-5 has two identical greys, whereas number-1 shows the greatest contrast. Number-2, 3, and 4 have intermediate contrasts. After appropriate treatment, the treated and original specimens are kept side by side and the change in color of the treated specimen when compared to the original one is assessed and graded with reference to grey scale. When there is no change in color of the test specimen it would be classified as ‘5’. If there is a change it is then classified with the number of the scale that shows the same contrast as that between treated and original specimens.

6. 2. Degree of staining grey scale: A different set of grey scale is used for measuring staining. Fastness rating 5 shows by two identical white samples (that is no staining) and rating 1 shows a white and grey sample. The other numbers show the geometrical steps of contrast between white and a series of grey. Here a piece of untreated, undyed, unstained cloth is compared with the treated sample (if possible a multifibre fabric) which was in contact with the test dyed specimen during the staining test. Finally this is compared with staining grey scale and thus a grading i.e. numerical assessment of degree of staining is given.

7. Color Fastness Rating Fastness grade Shade change of tested sample Fastness quality Staining of adjacent white sample 5 No change Excellent No staining 4 Slight loss in depth Good Very slight staining 3 Appreciable loss Fair Moderate staining 2 Significant loss Poor Significant staining 1 Great loss in depth Very poor Deep staining

8. Multifiber Fabric (MFF) Filament Triacetate, Bleached Cotton, Spun Polyamide Type 6.6, Spun Polyester Disperse Dyeable, Spun Polyacrylic and Spun Viscose. (TV) Filament Acetate, Bleached Cotton, Spun Nylon 6.6, Spun Polyester, Spun Acrylic and Worsted Wool. (DW) Regenerated Cellulose, Bleached Cotton, Spun Nylon 6.6, Spun Polyester, Spun Acrylic and Worsted Wool.  (LW)

9. Color fastness to Wash Principle of wash fastness: A dyed material is laundered, rinsed and dried in contact with specified adjacent fabric (MFF). The special composite sample is treated under appropriate condition in a chemical bath for a recommended time. The abrasion action is accomplished by the use of liquor ratio and an appropriate number of steel balls. The change in color of dyed sample (specimen) and the staining of the adjacent fabric (MFF) is assessed by recommended Grey scale.

10. Color fastness to Wash Apparatus and Material needed: Wash wheel with a thermo statically controlled water bath rotating speed of 40 ± 2 rpm. Stainless steel container of capacity 55 ± 5 ml. Stainless steel ball of diameter 0.6 cm and weight 1 gm. SDC MFF (Acetate, Cotton, Nylon, Polyester, Acrylic, Wool) Thermometer Sewing machine Dryer Color matching cabinet ISO scales

11. Color fastness to Wash Reagents: Reference detergent Sodium carbonate /soda ash Distilled water (Grade-3) Sample Preparation: A sample of dyed goods of size 10cm×4cm is cut and sew with same size MFF. This is the composite test sample.

12. Test method Temp( C) Time M:L Ratio Reagents Steel balls ISO Recommendation No. 1 (ISO 105 C01) 40º ± 2ºC 30 min 1:50 Only soap (5 g/lit) ISO Recommendation No. 2 (ISO 105 C02) 50º ± 2ºC 45 min 1:50 Only soap (5 g/lit) ISO Recommendation No. 3 (ISO 105 C03) 60º ± 2ºC 30 min 1:50 Soap(5g/lit)+ Anhydrous Sodium carbonate(2gm/L) ISO Recommendation No. 4 (ISO 105 C04) 95º ± 2ºC 30 min 1:50 soap (5g/lit)+ Anhydrous Sodium carbonate(2gm/L) 10 ISO Recommendation No. 5 (ISO 105 C05) 95º ± 2ºC 4 hours 1:50 soap (5g/lit)+ Anhydrous Sodium carbonate(2gm/L) 10

13. Color Matching Cabinet Evaluation: Compare the contrast between the treated and untreated sample with the Grey Scale and staining of color in the adjacent multi-fiber fabric with the staining Grey Scale. This assessment is done in a color matching cabinet.

14. Light Fastness Light fastness is the resistance to fading of dyed textiles when exposed to daylight. Exposure to sunlight is a test of the behavior of the sample under actual conditions of use but takes long time. ISO recommended that, The sample should be tested together with standard dyed wool controls of light fastness 1-8 respectively. Procedure: In standard condition- The sample and standards are mounted half covered and half exposed to daylight. The sample must be protected from rain by a glass sheet not less than 5cm away (well ventilation due to moisture and heat). The specimen and standards should be kept under sun and continue 24hrs until sufficient fading. Reference sample and the tested sample are cut at same size and those are accommodated on the template. The specimens are mounted in a frame facing south in northern hemisphere and facing north in southern hemisphere at an angle equal to the latitude of the place. The way of carrying out the test is to mount the standards and specimens as-

15. Fastness rating Dye C.I. number 1 Acilan Brilliant +Blue FFR Acid Blue 109 2 Acilan Brilliant +Blue FFB Acid Blue 109 3 Coomassie Brilliant +Blue R Acid Blue 109 4 Supramine Blue EG Acid Blue 109 5 Solvay Blue RN Acid Blue 109 6 Alizarine Light Blue 4GL Acid Blue 109 7 Soledon Blue 4BC powder Sol. Vat Blue 5 8 Indigozol Blue AGG Sol. Vat Blue 8 4. The sample must be protected from rain by glass sheet. 5. One quarter of the sample and standards are covered with opaque fabric. Thus it is exposed until standard-1 will be fade and equivalent to standard-4 on change in color grey scale. 6. Then cover up one quarter of previously exposed portion of the sample and standards by another opaque sheet. Thus it is exposed until standard-7 will be fade and equivalent to standard-4 on change in color grey scale

16. 7. Result will be terminated and opaque will be taken out, three stripes will be found in specimen and standards. 8. The zones of specimen are compared with zones of standards. The light fastness of a dyed sample is the number of the wool standard that has faded to same extent as the exposed area of the sample. Light fastness grades- Grade Degree of fading Light fastness type Grade-8 No fading Out standing Grade-7 Very slight fading Excellent Grade-6 Slight fading Very good Grade-5 Moderate fading Good Grade-4 Appreciable fading Moderate Grade-3 Significant fading Fair Grade-2 Extensive fading Poor Grade-1 Very extensive fading Very poor

17. Rubbing fastness Rubbing fastness is the resistance to fading of dyed textiles when rubbed against a rough surface. This test determines the fastness of dyestuff to either wet or dry rubbing. Procedure: Test specimen 15cm x 5cm (may be more, it has no effect) is placed on the base of the Crockmeter . Square of white test cloth (5cm x 5cm) of cotton desized , bleached but without finish (as ready to dye) Specimen is attached to the finger of the crockmeter . This finger is used in rubbing action on the sample specimen i.e. rubbing 10cm long to and for 10 times at 10seconds. 20 rubs in 10s and finger pressure on the specimen is 9N . For testing dry and wet rubbing, separate sample is used. Rubbing test is both for warp way and weft way. For wet rubbing, sample is dry but standard cloth is wet. Change in color in the specimen and staining in the white cloth is determined by grey scale. In both cases, for both dry and wet rub test, the fastness to rubbing is rated 1-5. Rating 1 means the worst rubbing fastness. Rating 5 means the best rubbing fastness.

18. Handle Counter Specimen Holder Rubbing Finger Crock meter ISO Crocking Cloth Crock meter Attachment Clip

19. Perspiration Fastness The garments which come into contact with the body where perspiration is heavy (like neck, under arm etc ) may suffer from serious local discoloration. Fastness to perspiration is the resistance to color of textile against the discoloration effect of acidic or alkaline perspiration. Two artificial perspiration solutions are made as follows- Chemicals Solution A Solution B l - histadine monohydrochloride mono-hydrate ( C 6 H 9 O 2 N 3 HCl.H 2 O ) 0.5gm 0.5gm Sodium chloride 5.0gm 5.0gm Di-sodium hydrogen orthophosphate ( Na 2 HPO 4 .2H 2 O ) 2.5gm 2.2gm Distilled water 1000ml 1000ml P H (adjust with NaOH ) 8 5.8

20. Perspirometer Acrylic glass plate (11.5cm × 6cm × .15cm) Weight 10 lb.

21. Procedure: 1. Sample size (10cm x 4cm) is taken. 2. The sample (10cm x 4cm) is placed between two undyed fabric pieces (5cm x 4cm). 3. One of the two pieces of undyed sample, if available, one should be a multifibre fabric . This fabric has different fibres side by side. One of the compositions from multi- fibres should be considered as the same fabric of the tested sample and other would be indicated as below- If the first piece is The second piece will be Cotton Wool Wool Cotton Silk Wool Linen Wool Viscose Wool Cellulose Acetate Viscose Polyamide Wool or viscose Polyester Wool or cotton Acrylic Wool or cotton

22. Question Which factors affect the fastness properties of colored textile materials? [3] How to assess colored textile with grey scale? [2] Explain the testing procedure of color fastness to rubbing. [5.5] Explain the testing procedure of color fastness to wash. [5.5]