Dye fastness refers to the ability of dyes or pigments to maintain their original color under the influence of various external factors during use or post-dyeing processing of dyed products. , which is also a quality requirement for dyed and printed fabrics.
Because dyed fabrics may become discolored or discolored due to light, sweat, friction, washing, ironing, etc. during wearing and storage. , thus affecting the appearance and aesthetics of fabrics or clothing. The nature or degree of dyeing state variation can be expressed by dyeing fastness.
The dye fastness of fabric is related to fiber type, yarn structure, fabric organization, printing and dyeing method, dye type and external force.
It can be divided into sun fastness, washing or soaping fastness, rubbing fastness, perspiration fastness, ironing fastness and sublimation fastness, etc. .
Let’s take a closer look at “How many types of dye fastness are there in textiles?”
Sunlight fastness
Sunlight fastness refers to the degree to which colored fabrics change color due to sunlight.
The test method can be either sunlight exposure or insolation machine exposure. The fading degree of the sample after exposure is compared with the standard color sample. There are two grading standards: wool blue label and gray card.
National and European standards are divided into 8 levels, with level 8 being the best and level 1 being the worst; American standards are divided into level 5, with level 5 being the best and level 1 being the worst. The worst level.
Fabrics with poor sun fastness should not be exposed to the sun for a long time and should be placed in a ventilated place to dry in the shade. Generally, a xenon lamp is used for 24 hours of testing.
Washing fastness
Washing or soaping fastness refers to dyeing The degree of color change of fabrics after being washed with detergent.
Usually the gray graded sample card is used as the evaluation standard, 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, with level 5 being the best and level 1 being the worst. Fabrics with poor washing fastness should be dry cleaned. If wet cleaning is performed, extra attention should be paid to the washing conditions, such as the washing temperature should not be too high and the washing time should not be too long.
Washing fastness is divided into two indicators, the original change and the staining of white cloth. The staining of white cloth is divided into cotton, nylon, polyester, wool, acrylic and acetate. Six types of fiber. The test temperature is 40/50/60/95 degrees. Generally, silk and wool use 40 degrees, and cellulose fibers use 60 degrees.
Friction fastness
Friction fastness refers to the degree of color fading of dyed fabrics after rubbing, which can be divided into dry rubbing and rubbing fastness. Wet friction.
The rubbing fastness is evaluated based on the degree of staining of white cloth, and is divided into 5 levels (1-5). The larger the value, the better the rubbing fastness.
Perspiration fastness
Perspiration fastness refers to dyed fabrics Degree of discoloration after exposure to sweat.
Since the composition of artificially prepared sweat is different, the perspiration fastness is generally assessed in combination with other color fastnesses in addition to being measured separately.
Perspiration fastness is divided into levels 1 to 5. The higher the level, the better. In European standards and national standards, perspiration fastness is divided into color fastness to acid perspiration and color fastness to alkali perspiration.
Ironing fastness
Ironing fastness refers to the degree of discoloration or fading of dyed fabrics when ironed.
The degree of discoloration and fading is evaluated by the staining of other fabrics by the iron at the same time.
Ironing fastness is divided into levels 1 to 5, with level 5 being the best and level 1 being the worst. When testing the ironing fastness of different fabrics, the ironing temperature for the test should be selected.
Sublimation fastness
Sublimation fastness refers to the stability of dyed fabrics during storage The degree of sublimation phenomenon that occurs in.
Sublimation fastness uses a gray grading sample card to evaluate the degree of discoloration, fading and white cloth staining of fabrics after dry heat pressing. It is divided into 5 levels.
Level 1 is the worst and level 5 is the best.
This test is generally used for polyester fabrics dyed with disperse dyes.
Chlorine immersion fastness
Chlorine immersion fastness is generally Be sure to wear some swimming suits because seawater contains chlorine, which can easily cause the fabric to fade.
Nowadays, city tap water also contains available chlorine. Some hospital and hotel supplies need to be disinfected with chlorine-containing detergents, so more and more requirements have been put forward on the resistance to chlorine bleaching fastness. The higher theAsk for.
Perspiration and light fastness Some fabrics have been tested to have very good perspiration fastness and light fastness.
However, in actual use, especially in summer, it is easy to fade due to sweat and sun exposure.
This puts forward a new requirement, and at the same time, new standards are produced.
Peroxide fastness
Current washing powders are medium-sized Some add peroxides such as peracetic acid and some activators, which cause the textiles to be oxidized and fade during the washing process. Therefore, the color fastness of textiles must have a certain tolerance to peroxide.
The dye fastness of normal fabrics generally needs to reach level 3~4 to meet the needs of wearing.
Others include weather fastness, color fastness, saliva fastness, blister fastness, dry cleaning fastness, etc. , these fastnesses have put forward increasingly higher requirements for the printing and dyeing processing of textiles.
