Color fastness is a term used in the textile industry to describe the resistance of a fabric against color fading or color transfer. We can define colorfastness as, having color that will not run or fade with washing or wear. That means characterizes a material’s color’s resistance to fading or running. Clothing is colorfast if its colors and dyes do not bleed or run from the clothing. Clothing should be tested for colorfastness before using any type of bleach or bleaching solution, or strong cleaning product. Colorfastness is very important factor for buyer. Color fastness properties of textiles are an important measure of quality of a product.
To test for colorfastness, find a hidden seam of the garment or an hidden spot. Apply the cleaner to the garment and then dab the area with a clean cotton cloth.
If the color removes itself from the garment onto the cloth, you should not use the cleaning product on the clothing.
If a fabric is non-color fast, the dye isn’t fully fixed onto the fabric, meaning that it might fade and run into other items of clothing. The quality of dye or method of dyeing used on a fabric can affect its color fastness, and often new items of clothing will be less color fast than those that have been washed a few times.
A color fast fabric is resistant to fading and running, so it is safe to be washed as usual with other items of clothing. Regardless of color fastness, clothes should be washed with similar colors to ensure that colors are kept vibrant and whites are kept bright.
Material composition affects a great deal for color fastness. By nature, some materials are always better than others when color fastness is concerned.
For instance, the color fastness of Polyester and Nylon fabrics are normally one grade better than Denim’s and Canvas’s. Therefore, the common standard for Denim, Canvas, Print Textiles, Velvet Textiles and Genuine or Suede Leather is set at a relatively lower level, which is only Dry: 3.0 and Wet: 2.0, as people in the industry understand and expect that it is difficult for these materials to achieve a high color fastness standard.
As such, during product development, when these fabrics are involved, it is better to pay special attention to make sure that the material suppliers would handle the fabrics carefully. Otherwise, you might end up with a product that will stain clothes.
Color also affects color fastness. Materials in darker colors tends to have lower color fastness than lighter color materials.
Also, due to the chemical properties of the dye, there are a few colors that are now widely known to be more problematic, such as Red, Navy Blue & Black.
Other factors that affect color fastness include the specific dye used in the dyeing process, the dyeing process itself, any additives, fixatives or softeners used, and the way of washing of the fabrics etc.
•The chemical nature of the fiber. For example, cellulosic fibers dyed with reactive or vat dyes will show good fastness properties. Protein fibers dyed with acid mordant and reactive dyes will achieve good fastness properties and so on. That is to say compatibility of dye with the fiber is very important. •The molecular structure (e.g.) of a dye molecule: If the dye molecule is larger in size, it will be tightly entrapped inside the inter-polymer chain space of a fiber. Thus, the fastness will be better.
•The manner in which the dye is bonded to the fiber or the physical form present.
•The amount of dye present in the fiber i.e. depth of shade. A deep shade will be less fast than a pale or light shade.
•The presence of other chemicals in the material. •The actual conditions prevailing during exposure.
Ironing Sublimation Color fastness is mainly used to determine the ability of various kinds of colored textiles to withstand high temperature, hot pressing and hot roller processing. It can provides data for the rational use of dyes to determine the printing and dyeing process parameters.c It can also be used to determine the quality of printing and dyeing finished products.
Sublimation Fastness Tester
Scorch Tester (Sublimation Fastness tester), to determine fabrics Ironing color fastness and sublimation color fastness, and dimensional stability under hot dry conditions.
Heating plate temperature and test time are adjustable, fitted with microprocessor temperature controller and the top plate with precisely controlled weight. The independent heating plate ensures controlling test temperature and thickness of sample individually.
Thermal and Water Vapor Resistance Testing – Using a “sweating guarded hotplate,” Intertek tests for Thermal Resistance (Rat) and Water Vapor Resistance (Ret) according to ISO 11092, EN 31092 and ASTM F1898 standards. Thermal resistance testing ensures reduction of heat transfer in garments, while water vapor resistance testing indicates sweat-friendly clothing that allows water vapors to pass through fabric and evaporate quickly for comfort. These tests can be performed on fabrics, films, coatings, foams and leather, including multilayer assemblies, for use in clothing, quilts, sleeping bags, upholstery, and similar products.
Sublimation Fastness Tester is used to determine Ironing color fastness and sublimation fastness of fabrics, Scorch tester complies with standards ：
• ISO 105
• BS 1006
• AATCC 92/114/117/133
• DIN 54022/54060,
• JIS L0879/L0850/L0879
• GB/T 5718/6152
Sublimation Fastness Tester Application:
Scorch Tester(Sublimation Fastness tester),to determine fabrics Ironing color fastness and sublimation color fastness, and dimensional stability under hot dry conditions, Heating plate temperature and the distance between are adjustable, equipped with electronic temperature controller and the top plate with precisely controlled weight. The temperature of each heating plate can be controlled individually.
How to Avoid the Problem Due to Poor Sublimation Fastness
Sublimation is the process of phase change from solid to gas, without going into liquid phase.
Fastness to sublimation is probably the most important requirement of dyed polyester, apart from fastness to light. The migration behavior and wet fastness of disperse dyes on polyester are closely involved with their response to heat treatments.
Adequate fastness to heat is essential so that the dyed material will withstand the conditions encountered in：
1. Heat setting,
2. Durable pleating
3. Ironing or pressing of the goods during the making-up of garments.
4. Finishing processes where high temperature is involved.
5. Thermal fixation of prints.
The poor sublimation fastness results into following problems：
1.Change in original shade
2.Staining on adjacent fibers in contrast dyed fabrics.
3.Poor color yield and fixation rate in thermal fixation of prints.
4.Staining of dyed polyester sewing threads after stitching and embroidery in contrast stitched and embroidered articles.
5.Cross staining during storage.
Since the problem of poor sublimation is concerned to polarity of substation groups in dye molecule , therefore following steps are suggested to avoid the problem：
1.Pre-heat setting most of the fabrics before dyeing.
2.Carefully selecting the dyes so that all component yarns have satisfactory fastness in multicolored/contrast color designs, where fabric is post heat set.
3.Selecting high sublimation dyes for dark shades and medium /low sublimation dyes for pale shades.
4.The sublimation fastness influenced by the dyeing conditions and dyeing cycle followed, therefore the dyeing cycles must be optimized for best sublimation fastness.
Information regarding online access to Sublimation Tester via TESTEX online can be found at http://www.testextextile.com/product/scorch-tester-sublimation-fastness-tester-tf415d/.