Dyeing fastness refers to the ability of dye or pigment to maintain its original color and lustre under the influence of various external factors during the use or processing of dyed products.It is also the quality requirement of dyeing and printing fabrics.Ken color or discoloration will occur to dyed fabrics during wear and storage due to light, sweat, friction, washing, ironing and other reasons, which will affect the aesthetic appearance of fabrics or clothing.The nature or degree of variation in staining status may be indicated by color fastness.The dyeing fastness of fabric is related to fiber type, yarn structure, fabric structure, printing and dyeing method, dye type and external force.It can be divided into insolation fastness, water or soap wash fastness, friction fastness, perspiration stains fastness, ironing fastness and sublimation fastness.
1. Light fastness
Sunfastness refers to the degree to which colored fabrics change color when exposed to sunlight.The test method can be used either by sun exposure or by sun exposure machine. The faded degree of the sample after sun exposure is compared with the standard color sample. The grading standard has two kinds of wool blue standard and gray card.The US standard is divided into five levels, with five being the best and one the worst.The fabric with poor insolation fastness must avoid long insolation below sunshine by all means, be put in ventilated place shade dry.The general use of xenon lamp irradiation 24 hours test.
2. Washing fastness
Washing or soap-washing fastness refers to the degree of color change of dyed fabric after washing with detergent.Gray grading sample card is usually used as the evaluation standard, which depends on the color difference of the original sample and the sample after fading.There are five levels of wash fastness, with 5 being the best and 1 the worst.Fabrics with poor washing fastness should be dry cleaned. If wet washed, double attention should be paid to washing conditions, such as washing temperature should not be too high or time should not be too long.Washing fastness is divided into two indicators, the original change and white cloth staining, white cloth staining is divided into cotton, nylon, polyester, wool, acrylic, acetate six kinds of fiber.The test temperature is 40/50/60/95 degrees, general silk and wool use 40 degrees standard, cellulose fiber use 60 degrees.
3. Rubbing fastness
Rubbing fastness refers to the color loss of dyed fabric after friction, which can be divided into dry friction and wet friction.The rubbing fastness is evaluated by the degree of staining of white cloth, which is divided into 5 grades (1-5). The greater the value, the better the rubbing fastness.
4 Perspiration fastness
Perspiration fastness refers to the degree of discoloration of dyed fabric soaked in sweat.Perspiration fastness because of the artificial preparation of sweat components are not the same, so generally in addition to separate determination, but also with other color fastness together assessment.Perspiration fastness is rated from 1 to 5, with the higher the better.In European standard and national standard, perspiration fastness is divided into acid perspiration fastness and alkali perspiration fastness.
5 Fastness to ironing
Ironing fastness refers to the discoloration or discoloration of a dyed fabric during ironing.The degree of discoloration and discoloration is assessed by the simultaneous staining of other fabrics with the iron.Ironing fastness is rated from 1 to 5, with 5 being the best and 1 the worst.When testing the ironing fastness of different fabrics, the ironing temperature should be selected for testing.
6 Sublimation fastness
Sublimation fastness refers to the degree to which sublimation occurs in the dyed fabric during storage.Sublimation fastness The color discoloration, fading and staining degree of white cloth after dry pressing were evaluated by grey grading sample card, which were divided into 5 grades, the first grade was the worst and the fifth grade was the best.This test is generally used for dyeing polyester fabrics with disperse dyes.
7.Chlorine immersion fastness
Chlorine immersion fastness is generally aligned with some swimming suits, because the seawater contains chlorine, which will easily fade the fabric. Nowadays, urban tap water also contains available chlorine. Some hospitals and hotel supplies need to be disinfected with chlorine-containing detergents. Therefore, higher and higher requirements are put forward for the fastness to chlorine bleaching.
8 light fastness to perspiration
Some fabrics are tested to have good perspiration fastness and light fastness, but in actual use, especially in summer, it is easy to fade with sweat and sunlight. This puts forward a new requirement, and at the same time , A new standard was born
9 fastness to peroxide
Most of the present washing powders are added with peroxides such as peracetic acid and some activators, which cause the textiles to be oxidized in the washing process and fade.So the textile color fastness to have a certain tolerance to peroxide.
Normal fabric dyeing fastness, generally required to reach 3~4 grade to meet the needs of wearing.
Other fastness include weather fastness, SOB fastness, saliva fastness, blister fastness, dry cleaning fastness, etc. These fastness put forward higher and higher requirements for textile printing and dyeing processing.