The factors that affect the color fastness to sunlight of textiles include internal and external factors. The internal cause is mainly caused by the difference of textile dyes' own properties. External factors include many aspects, such as light source selection, spectral energy, temperature setting, relative humidity, etc. As the internal cause of textile color fastness to sunlight is the purpose of the test, it has little to do with the test method. However, external factors directly affect the stability and reproducibility of test results. The light source includes visible light visible to human eyes, short-band ultraviolet light and long-band infrared light invisible to human eyes in normal solar light. All kinds of wavelengths of light may cause the chemical properties of textiles to change. Studies have proved that the length and energy of ultraviolet light have the most obvious influence on the color fastness to sunlight of textiles. At present, the light sources mainly used for testing the light fastness of textiles include xenon lamps and ultraviolet fluorescent lamps. However, ultraviolet fluorescent lamps are mainly used for the aging test of outdoor textiles, while ultraviolet, visible and infrared rays generated by xenon arc lamps are the artificial light sources closest to sunlight at present. Therefore, xenon arc lamp is used as a reference object. The selection and control of light source for textile color fastness to sunlight mainly need to consider the following two aspects: filter system and irradiation intensity. The stability of light source irradiance and the size of light source irradiance are directly related to the decomposition speed of textile dyes, thus affecting the color fastness to sunlight of textiles. Therefore, the control of irradiance is very important. At the same time, the output power of the xenon lamp and the aging phenomenon of the filter should be taken into account when selecting the appropriate xenon lamp and filter in the light fastness test of textiles, because the above two factors will directly affect the change of the light source spectrum, which will lead to a certain spectral drift phenomenon when the spectrum emitted by the xenon lamp reaches the surface of the sample in the later period.
Filter system
At present, the filters used are mainly divided into three types: sunlight filter, ultraviolet extension filter and window glass filter. Sunlight filter is mostly used for outdoor products. The ultraviolet extension filter is mostly used in the automobile industry. Window glass filters are most commonly used in textile testing. According to the requirements of the current textile color fastness standards, the most common filters are glass IR filter and glass B/SL filter. The glass IR filter is commonly used in the tests of textile color fastness to sunlight according to ISO and GB/T standards, while the glass B/SL filter is commonly used in the tests of textile color fastness to sunlight according to AATCC standards. The temperature of the color fastness to sunlight system is an important indicator of the color fastness to sunlight system, and changes in temperature will inevitably lead to changes in chemical indicators of test samples. The combination of light and high temperature will lead to accelerated degradation of textiles. Therefore, the light fastness test of textiles should not only consider the light wave band and radiation intensity received by the surface of the test sample, but also the surface temperature of the sample and the ambient temperature.
2.1. Blackboard thermometer
In the light fastness test of textiles, the surface temperature of the sample is usually obtained by measuring the temperature of the standard metal plate. There are two commonly used standard metal plates, one is a non-insulated blackboard thermometer (BPT) and the other is a black standard thermometer (BST) mounted on an insulated plastic plate. The temperature indicated by the blackboard thermometer (BPT) is the sum of the transfer temperature of the blackboard heated air and the temperature rise irradiated by the light source. Because the blackboard thermometer (BPT) uses a metal plate surface similar to a black body as a temperature sensing element and is placed on a sample rack in parallel with the sample, and the black body has heat absorption capacity, the temperature indicated by the blackboard thermometer (BPT) generally represents the relatively high temperature that the sample may reach. The Black Standard Thermometer (BST) is a blackboard thermometer with an adiabatic base developed since both the blackboard thermometer (BPT) and the sample holder are made of metal sheets, which has fast heat dissipation and is inconvenient to reflect the temperature rise of dark samples with poor thermal conductivity. The black mark thermometer (BST) is more suitable for displaying the temperature of the exposed surface of the dark sample with poor thermal conductivity, and the temperature displayed by the black mark thermometer (BST) is higher than the temperature displayed by the blackboard thermometer (BPT), thus being more suitable for monitoring the upper limit of the allowable test temperature.
2.2. Color fastness to sunlight system box air temperature
The temperature of the air in the box of the color fastness to sunlight system directly affects the surface temperature of the sample, the temperature of the blackboard and the humidity of the air in the box, which will later affect the test results of the sample.
3. Relative humidity of color fastness to sunlight system
The aging factors of textiles mainly include light radiation, temperature and relative humidity. When the humidity increases, the water solubility of most dyes increases and the decomposition speed also increases. In the current standard, the effective humidity is defined by combining the air temperature, the surface temperature of the sample and the relative humidity of the air that determines the moisture content on the surface of the sample during insolation. Humidity control standard sample is made of cotton fabric dyed with red azo dye, which is simply called humidity control red cloth. With the increase of effective humidity, the color fastness to sunlight of humidity-controlled red cloth decreased significantly.
References:
[1] GB/T 84272008 Textiles - Tests for colour fastness - Colour fastness to artificial light; Xenon arc.
[2] ISO 105 B02; Textiles - tests for colour fastness - part B02: colour fastness to artificial light: xenon arc.
[3] AATCC TM 162004Colorfastness to Light.
[4] Zhu Shu sheng, Zhang Heng, sun Xing lei. correlation study on color fastness to sunlight of textiles. textile standards and quality, 2014 (2): 5154.
[5] Ren Guang. The influence of light fastness test system on textile color fastness test results. Dyeing and finishing technology.
YG611M AIR-COOLED WEATHER CONDITIONS METER
YG611M AIR-COOLED WEATHER CONDITIONS METER
Uses: Used for light fastness, weather fastness and light aging tests of colored materials such as textile, printing and dyeing, clothing, automotive upholstery, geotextile, leather, plastic, etc. By controlling the items of light irradiance, temperature, humidity, rain and the like in the test chamber, the simulated natural conditions required by the experiment are provided to detect the light fastness, weather fastness and light aging performance of the sample; With on-line control of illumination intensity; Automatic monitoring and compensation of illumination energy; Closed loop control of temperature and humidity; Blackboard temperature loop control and other multi-point adjustment functions. Comply with U.S., European and national standards. Compliance with standards: AATCC16 16,169, ISO105B02, ISO 105B04, GB/T 8427, GB/T 8430, GB/T 14576, GB/T 15102, GB/T 15104, SAEJ1960, 1885, JASOM346, PV1303, ASTM G1551, 1554, etc. When FY601 ultraviolet aging box rubber, plastic and other materials are used indoors and outdoors, they will inevitably be exposed to sunlight or sunlight filtered by glass for a long time, and ultraviolet rays in sunlight are the main factors that lead to the decline of product performance. Therefore, it is very necessary to use fluorescent ultraviolet lamps to simulate sunlight for aging test of materials. According to different wavelengths, there are mainly UVA340, UVA351, and UVB313 tubes, in which the percentage of radiation below 300nm in UVA340 tubes is less than 2 % of the total radiation, and the peak value of radiation energy is at 340nm wavelength. According to the spectral comparison with sunlight, it can be found that UVA340 has a better spectral correlation with outdoor sunlight exposure. Therefore, UVA340 can be used to detect the aging performance of rubber, plastic and other materials under outdoor sunlight exposure. In addition to ultraviolet rays, there are also humid environments that cause the deterioration of material properties. There are mainly two ways to simulate sample moisture, namely spraying and condensation. Spray simulates the rain environment by spraying the sample through an atomizing nozzle, while condensation generates saturated water vapor and condensation on the surface of the sample by increasing the water temperature. The ultraviolet aging box refers to GB/T16422.32014 " Test Method for Exposure of Light Sources in Plastic Laboratories" and GB/T145222008 " Plastics, Coatings and Rubber Materials for Mechanical Industrial Products - Artificial Climate Accelerated Test Method Fluorescent Ultraviolet Lamp" standards, which can reproduce the aging of materials caused by sunlight, dew and rain. The equipment carries out the test by insolating the material to be tested in the controlled interaction cycle of sunlight and moisture while increasing the temperature. The equipment is irradiated by ultraviolet fluorescent lamps and can simulate the influence of moisture by condensation or spraying. It is a necessary testing equipment in aviation, automobiles, household appliances, scientific research and other fields, and is used to evaluate the changes of materials in fading, color change, luster, crack, foaming, embrittlement, oxidation and other aspects. Compliance with standards: GB/T318992015, GB/T306692014, GB/T16422.32014, GB/T145222008, etc.
Instrument characteristics:
1. Large screen color touch screen display operation.
2. The core control unit is a 32-bit single-chip microcomputer of Italy Company, which is composed of multi-function motherboard.
3, the instrument surface spray adopts the better electrostatic spray craft, neat and beautiful.
4. The heating mode is tank-type heating, the heating speed is fast, and the temperature distribution is even.
5. The drainage system uses vortex-return type and U-type sedimentation device to drain water, which is convenient and convenient.
6. The water level of the inner tank is automatically replenished.
7. The lid of the box is a two-way flip cover, which is easy to open and close.
8. The bottom of the test box adopts high-quality fixed PU movable wheel, which is easy to move.
9. The independent control time of illumination and condensation and the alternation cycle control time can be set arbitrarily within one thousand hours.
Technical parameters:
1. Studio size: 450 × 1150 × 450mm.
2. The number of sample shelves: 24 groups (one group can hold two samples, the exposure size of the sample is 65 × 95mm).
3. Central distance between lamp tubes: 70mm.
4. Temperature range: RT10 ℃ ~ 80 ℃.
5.Lamp Type: UVA340 fluorescent Lamp.
6. The time of exposure, condensation and spray can be adjusted alternately.
7. The test time: 0-999H can be adjusted.
