Light Fastness Tester

Common Quality Problems and Causes Analysis of Light Fastness Tester

Date：2016-05-9|Author：QINSUN |

Common problems of Light Fastness Testeroccurred mainly on cotton and cotton blended products. Dye variety used for dyeing cotton fibers are: direct dyes, insoluble azo dyes, vat dyes and reactive dyes. Which in addition to section, dark cotton products still use a small amount of vat dyes; other dyes for dyeing cotton fiber from its chemical structure point of view, the vast majority belong to azo dyes. In the practical application of these dyes, the problem often found in color fastness to light some of the more serious product, color and light fastness and color depth is proportional to the product staining. 

Azo dye photo bleaching effect is more complex, with reactive dyes present in the dyeing of cotton fiber is widely used as an example, the decisive factor causing dye photo-fading dye is the parent structure of the azo group. Light poor stability of azo basic body, in the light conditions, prone to photo-oxidation decomposition. But studies show that not all azo dyes have emerged as a consistent light stability, some good, and some poor. This is directly related to the status of an azo group and adjacent groups share the electron cloud of dye 

Most of the yellow reactive dyes is a pyrazolone, pyridone or 2-aminonaphthalene, 3, 6, 8-sulfonic acid as coupling component three synthetic monoazo dye, an azo group in the ortho-position and para-sulfo acid group, a halogen or heterocyclic ring having the presence of electron-withdrawing groups. Because these effects induced electron withdrawing group, the electron cloud density azo group on the decline, so that it has a high light oxidation stability, light fastness are generally better. 

Orange reactive dye is mostly in J acid as the coupling component synthetic mono azo dyes. Ortho presence of such dyes also have electron withdrawing functional sulfonic acid group. However, since the dye molecules in the presence of both an electron-donating groups, such as hydroxyl group and an amino group, so that the electron density azo group on the rise, not fall, and therefore color fastness to light yellow orange reactive dye is less reactive dyes

Red reactive dyes usually are H acid coupling components monoazo dye. Due to the hydroxyl group and an amino acid H two groups for electron impact, so the electron density on the nitrogen atom of the azo group increased significantly accelerated photo-oxidation of the azo group, and therefore cannot make its light fastness satisfactory 

To light the dye molecular structure oxidative stability azo group, usually in the synthesis of dyes, the azo group in the ortho introduces strong electron withdrawing groups, thereby reducing the electron density of the nitrogen atom of the azo group. In addition, it can also be introduced in the two ortho hydroxy azo groups, using its coordination capacity, with heavy metal complex to form a metal complex dye, an azo group to reduce the electron density of the nitrogen atom, two pairs of azo play a role in shielding the base, and ultimately improve the light fastness dyes. Purple dye mostly made of copper complex azo dye, has a good light fastness

Architecture blue dye precursor of many types of reactive dyes, phthalocyanine structure are generally copper complex dyes, excellentLight Fastness Tester; anthraquinones structure has good light fastness; but most of the blue activity H acid dye is still prepared disazo dyes, although better than the red dye color fastness to light, but overall still cannot meet the all needs.

Reactive dye Light Fastness Tester, its most important factor is the structure and properties of the dye, but the nature of cotton fabric dyeing method, solid color processing technology and textile finishing and other factors also affect the color fastness to light products, but relatively the dye itself, these effects are much smaller.   

In addition, a large number of experiments show that light fastness of reactive dyes on cellulosic fibers dyed with a depth proportional to color, that the deeper the color, the better the color fastness to light, color and more light, color fastness worse . This is due to the concentration of the dye on the fiber, the greater the degree of aggregation of the dye molecules, the same amount of dye exposure to air, the smaller the surface area of moisture and light, and the chance of the dye was also lower photo oxidation. On the other hand, the color the more light, the dye on the fiber was mostly highly dispersed state, the higher the probability that light, color fastness to light eventually decreased 

Light Fastness Tester Standards:ISO，AATCC，ASTM，JIS A 1415，JIS L 0842

Light Fastness Tester Application: SUGA U48AU Durable accelerated aging test machine as Light Fastness Tester instrument has been widely accepted worldwide, the instrument used to test different materials and products, light aging. Suitable for fiber textiles, building materials, notebooks, office supplies and other common areas for a variety of testing standards of Light Fastness Tester.

Light Fastness Tester Feature：Source - long-life UV carbon rod, the ultraviolet range 388nm, can work continuously for 48 hours Control system - equipped with the humidity, continuous air supply means to achieve high-precision temperature and humidity control. Automatic air control system controls the mixing chamber circulating air and ambient air

 Light Fastness Tester Technical Parameters：

Item	parameter
light source	Carbon arc lamp
continuous working time of light	48 hours
Discharge voltage and current	135V±10V，16A±2A
temperature range	63℃±3℃
Humidity	35%rh to 50% ±5%rh
Humidity control	Atomizer
Temperature cycling	Air control valve regulates air circulation
Sample	The maximum amount of testing is108, Sample size is 65mm × 55mm, 1mm thick
power supply	Single-phase, 200V, 41A
size	（L x W x H）：104cm x95cm x 205cm
weight http://www.bizbilla.com/	354kg