How to test the color fastness of silicone pigments?
Rubbing color fastness test:
By simulating the situation that silicone products come into contact with other objects and rub against them during use, the color fastness of the color paste under friction is evaluated.
Test method: Generally, a friction color fastness instrument is used to fix the silicone sample on the platform of the instrument, and then a standard friction white cloth or other specified friction materials are used to rub the silicone surface at a specified number of times and speed under a certain pressure. Friction can be divided into dry friction and wet friction. Wet friction is to rub after a certain amount of water is dipped on the friction cloth. After the friction is completed, the depth of the color stained on the friction cloth is compared, and the gray sample card is used for rating. The higher the grade, the better the color fastness to friction.
Water washing color fastness test:
Simulate the degree to which the color of silicone products is affected by factors such as water and detergent during daily washing, and check whether the color of the color paste is easy to fade or change color.
Test method: Sew the silicone sample with the standard adjacent fabric, put it in an aqueous solution containing a certain concentration of detergent, and wash it under specified temperature, time and stirring conditions. After washing, after cleaning and drying, observe the color change of the silicone sample and the staining on the interlining fabric, and then use the gray sample card to rate the degree of discoloration and staining, so as to determine the color fastness to washing.
Perspiration color fastness test:
Considering that silicone products may be affected by sweat when in contact with human skin, the color fastness of the color paste is tested by simulating the effect of human sweat on the color of silicone.
Test method: Sew the silicone sample with the standard interlining fabric, soak it in the artificially prepared sweat solution for a certain period of time, take it out and clamp it on the sweat color fastness meter, put it in the oven and treat it at a constant temperature at a specified temperature. After drying, use the gray sample card to rate the discoloration of the sample and the staining of the interlining fabric to judge the color fastness to sweat.
Lightfastness test:
Since silicone products may be exposed to sunlight during use or storage, light will cause the color to fade or change color, so this test is to evaluate the color stability of the color paste under light conditions.
Test method: Xenon arc lamps, carbon arc lamps, and other artificial light sources are usually used to simulate natural sunlight. The silicone sample and the blue wool standard cloth are placed in a light test box and exposed according to the specified light intensity, time, and temperature. After the exposure, the color changes of the silicone sample and the blue wool standard cloth are compared. The lightfastness grade of the silicone color paste is evaluated according to the degree of fading of the blue wool standard cloth. The higher the grade of the blue wool standard cloth, the better the lightfastness.
Heat fastness test:
Test the color stability of the silicone color paste under high-temperature environments, because silicone products may be exposed to higher temperatures during production and processing or certain specific use scenarios.
Test method: Put the silicone sample in the oven, keep it under the set high temperature conditions for a certain period of time, then take it out and cool it to room temperature, observe the color change of the sample, and compare it with the original sample that has not been heat treated to evaluate its heat fastness. You can also use the hot press color fastness test method, where the dry sample is covered with cotton adjacent fabric, and then pressed in a heating device at a specified temperature and pressure for a certain period of time, and then the gray sample card is used to evaluate the color change of the sample and the staining of the adjacent fabric.
