One piece of fabric is the most troublesome is the color fastness ~ Xiaobian today to tell you about color fastness knowledge ~ very comprehensive and worth collecting oh ~ Color fastness concept: Color fastness, also known as color fastness, color fastness. Color fastness is also called color fastness and color fastness. It refers to the resistance of the color of textiles to various roles during processing and use. The fastness grade was evaluated based on the discoloration of the specimen and the coloration of the undyed patch. In the course of its use, textiles are exposed to various external functions such as light, washing, ironing, perspiration, friction and chemical agents. Some textiles and dyeings have also undergone special finishing processes, such as resin finishing, flame retardant finishing, sand washing, and grinding. Hair and so on, this requires that the color of the dyed textiles is relatively constant. Color fastness refers to the product's wash and rub resistance. The so-called color fastness (abbreviated as color fastness) means that the dyed fabric is subject to external factors (extrusion, friction, water washing, rain, sun exposure, light, seawater impregnation, saliva immersion, water stains, perspiration) during use or processing. Etc.) The degree of discoloration under action is an important indicator of fabrics. The most commonly used items are wash, light, friction and perspiration resistance, ironing resistance, and weather resistance. In actual work, test items are mainly determined based on the end use of the product and product standards. For example, wool textiles must be tested for color fastness to sunlight, knitted underwear must be tested for fastness to perspiration, and outdoor textiles. (such as parasols, light box cloths, canopy materials), of course, to test its color fastness to weather. Including: Color fastness to soaping (demonstration), color fastness to rubbing, color fastness to chlorine and water, color fastness to non-chlorine bleach, color fastness to dry cleaning, color fastness to actual washing (clothes, fabrics), perspiration resistance Color fastness, water fastness, light fastness, sea water fastness, saliva fastness. How to test the color fastness Water color fastness The sample is sewn together with a standard patch fabric, washed, washed and dried, and washed under suitable conditions of temperature, alkalinity, bleaching and rubbing so that the test results are obtained within a short period of time. The friction between them was achieved through the small bath ratio and the rolling and impact of a suitable number of stainless steel beads. The gray card was used for rating and the test results were obtained. Different test methods have different temperatures, alkalinity, bleaching and rubbing conditions and sample size, and specific selections should be made according to test standards and customer requirements. Generally washed with poor color fastness cuilan, brilliant blue, black red, navy and so on. 2. Dry fastness The same as the color fastness to washing, but it changed to dry cleaning instead of washing. 3. Rubbing fastness The sample was placed on a rubbing fastness tester and rubbed with a standard rubbing white cloth at a certain pressure for a certain number of times. Each set of samples was required to have dry rubbing fastness and wet rubbing fastness. The color on the standard rubbing white cloth was rated with a gray card, and the resulting series was the measured rubbing fastness. The color fastness to rubbing requires two tests: dry rubbing and wet rubbing. All colors on the sample must be rubbed. 4. Sun color fastness Textiles are usually exposed to light when they are used. Light destroys the dyes and causes a well-known "fade," discoloring colored fabrics, which generally become lighter, darker, and some shades of light change. Therefore, color fastness is required. Degree of testing, sun color fastness test, is to test the specimen with blue wool standard cloth with different fastness levels under the specified conditions for solar exposure, the sample and the blue wool cloth for comparison, evaluation of light resistance Color fastness, the higher the standard number of blue wool, the more lightfast. 5. Perspiration fastness The sample and the standard lining fabrics were sewn together and placed in perspiration solution, and then placed on a perspiration-resistant color fastness meter, placed in an oven at a constant temperature, then dried, and rated with a gray card to obtain test results. Different test methods have different perspiration ratios, different sample sizes, different test temperatures and times. 6. Water stain color fastness Samples treated with water were tested as above. Chlorine bleaching fastness: After the fabric is washed in a chlorine bleach solution under certain conditions, the degree of color change is evaluated. This is the chlorine bleaching fastness. 7. Non-chlorine bleaching fastness After the fabric was washed with non-chlorine bleaching washing conditions, the degree of color change was evaluated, which is the non-chlorine bleaching fastness. 8. Hot color fastness After the dry sample was covered with cotton lining fabric, it was pressed for a certain time in a heating device of a specified temperature and pressure, and then the color change of the sample and the stain of the lining fabric were evaluated with a gray sample card. Hot press color fastness is dry pressure, moisture pressure, wet pressure, according to different customer requirements and test standards, select the test method. Color fastness test type and fastness classification The nature or extent of the variation in the staining state can be expressed as the color fastness. The color fastness of fabrics is related to the type of fiber, yarn structure, fabric structure, printing and dyeing methods, dye type and external force. Tests for color fastness generally include light fastness, weather fastness, wash fastness, rub fastness, perspiration fastness, etc., sometimes according to different textiles or different use environments. Special requirements for color fastness. When the color fastness test is generally performed, it is the degree of discoloration of the dyed material and the degree of staining of the lining material. The color fastness is rated. In addition to the light fastness of eight, the rest are all five levels. The higher the number of stages, the better the color fastness. Light fastness The light fastness refers to the degree of discoloration of a colored fabric by sunlight. The test method is to simulate the degree of fading of the sample after the sunlight exposure and the standard color sample, and it is divided into 8 grades. The grade 8 is the best grade and the grade 1 is the worst. Fabrics with poor light fastness should not be exposed to sunlight for a long time and should be dried in a ventilated place. 2. Wash fastness Washing or soaping fastness refers to the degree of color change after the dyed fabric is washed with the washing solution. Gray graded sample cards are usually used as the evaluation criteria, that is, the color difference between the original sample and the sample after fading is used for evaluation. Washing fastness is divided into 5 levels, 5 is the best and 1 is the worst. The fabrics with poor washing fastness should be dry-cleaned. If the wet-cleaning is performed, the washing conditions must be doubled. For example, the washing temperature should not be too high and the time should not be too long. 3. Friction fastness Frictional fastness is the degree of discoloration of a dyed fabric after it has been rubbed, and can be all dry and wet friction. Frictional fastness is based on the degree of stained white cloth as the principle of evaluation. It is divided into 5 levels. The greater the value, the better the fastness to rubbing. 4. Perspiration fastness Perspiration fastness refers to the degree of discoloration of dyed fabrics after they have been soaked in sweat. 5. Ironing fastness It refers to the degree of discoloration or discoloration of dyed fabrics when they are ironed. 6. Sublimation fastness It refers to the degree of sublimation phenomenon that occurs during the storage of dyed fabrics. The color fastness of normal fabrics is generally required to reach level 3-4 to meet the needs of wearing. Method for improving fixation fastness of dyes Although some dyes can be dyed with brighter colors, due to the water-soluble groups on the dyes, the wet-fastness is not good, and the fading and staining are serious, which not only makes the appearance of the textile itself obsolete, but it also peels off the dyes. Stain to white or other color of the fiber, resulting in stained, color phenomenon. Â In addition, although reactive dyes can form covalent bonds with cellulose fibers, in the dyeing process, the presence of hydrolyzed dyes or insufficient soaping of unbound dyes can also result in a decrease in wet-fastness; Reactive dyes that have formed covalent bonds may also be decomposed and broken under acidic or basic conditions, as well as problems with chlorine fastness, perspiration fastness, and insufficient fastness to sunlight. Â In order to improve the color fastness of the fabric, fixing treatment can be performed. These additives, which can improve various types of color fastness, are called fixing agents. Â Fixing agent fixing principle 1. Insoluble lakes are formed on the fabric to block the soluble groups, so that the dye on the fabric is not easy to dissolve and fall off, so as to improve the fastness to wet processing. 100% Cotton Chambray Fabric,Polar Fleece Fabric,Polyester Jacquard Fabric,Poly Voile Fabric Shaoxing City Laiteng Imp.&Exp Co.,Ltd , https://www.laiteng-tex.com