Measures to improve the sunlight color fastness of fabrics
1. Selection of dyes
The choice of dye is key in improving the sun fastness. Should choose the three primary colors with high insolation fastness above all. In three primary colors, the sun high fastness of yellow dye as the pyridine moiety ketone and pyridine ketone as the coupled components or with 2 - amino - 3,6,8 - three naphthalene sulfonic acid as heavy nitrogen composition of azo dye, because they all azo group ortho introduced electronic base, make azo base on nitrogen atom's electron cloud density is lower, is not conducive to generate oxidation azo compound, Thus preventing or reducing photooxidation reactions, these dyes have good sun fastness, such as C.I. Active yellow 2(K type, grade 6-7), C.I. active yellow 145(KM type, grade 6-7), etc.
Blue chromatogram dyes with high fastness to sunlight are mainly anthraquinone type, phthalocyanine type and methyl lipid type as the parent structure, involving dyes such as C.I. anthraquinone structure. Reactive blue 2(grade 6-7), C.I. reactive blue 74(grade 6-7), phthalocyanine structure such as C.I. Reactive blue 14(grade 7 ~ 8), C.I. reactive blue 15(grade 6 ~ 7). The sun fastness of red chromatographic reactive dyes is generally low, especially in light colors. Only some azo groups and two adjacent positions contain hydroxyl coordination ability, forming stable chelating rings with copper, which can improve the sun fastness, such as C.I. Reactive red 23(grade 7), C.I. reactive red 7(grade 6 ~ 7) now the dye companies are developing new reactive dyes with good tanning fastness to meet the needs of the market.
Taiwan Yongguang Dye Company recommends a set of reactive dyes with high sun fastness for light color dyeing. Its primary colors are Everzol Yellow C -- GL, RedC 3B and Blue -- BB. MegafixBL high sun fastness reactive dyes from Wind, Ciba's CibacronPN and Clariant's DrimareneCL -- C all have good light sun fastness. At the same time, for the fabric that needs to match color, the fastness grade of each component dye should be the same, and the poor fastness of one component will affect the fastness of the whole mixed color. The dyes with relatively less content in the mixture can be selected as dyes with high sunfastness grade to ensure the sunfastness grade of the fabric as a whole.
2. Selection of soaping agent
In dyeing process, reasonable dyeing process should be developed, full soap washing, water washing, minimize the amount of hydrolyzed dye and floating color to improve the fastness to the sun. LTF - S800 is a good reactive dye soap, and the color fastness of the fabric can reach grade 4 ~ 5, which greatly reduces the floating color. Shanghai Daxiang Chemical Industry Co., LTD. C - 80DX is also a good soap detergent.
3.Selection of fixing agent
At present, there are roughly three kinds of fixing agent: cationic surfactant fixing agent, non-surface active quaternary ammonium salt type fixing agent and reactive type fixing agent.
3.1 Cationic surfactant color fixing agent
Most of them are quaternary ammonium salts, matte salts or phosphorus salts. This kind of fixing agent and dye generate lake on the fiber, although the washing fastness is very good, but often reduce the dye's original sun fastness. So when the sun fastness requirements are high, try to avoid choosing this kind of fixing agent.
3.2 Non-surface active quaternary ammonium salt color fixing agent
The fixing agent neither belongs to the synthetic resin, and does not have surface activity itself, generally contains two or more quaternary ammonium groups. This kind of fixing agent and copper salt can also improve the sun fastness of reactive dyes:
For example, fixing agent NFC is a mixture of cationic polyamine condensates and special metal salts. When applied, the color becomes smaller, does not affect the color fastness of dyeing, and has a good soap fastness.
3.3 Reactive fixing agent
Reactive dyeing with dye - fiber covalent bond, it has excellent fastness to wet processing, but some broken key will happen after dyeing, hydrolysis, in this case, the reactive fixing agent has both combined with fiber reactive group, and is able to combine with anionic dye cationic groups, the fixing agent, the crosslinking has better fastness.
This kind of fixing agent, such as LTG - 8080, does not affect the color light, and good sun fastness. In addition, LTF - S6F color fixing agent used in silk fabric can improve the fastness to washing and rubbing without affecting the fastness to hand feeling, color and sun exposure. Others such as Shanghai Daxiang Chemical Industry Co., LTD., fixing agent 3A powder, Shanghai auxiliary factory fixing agent DS, such as the use of this kind of fixing agent, the color of the fabric becomes smaller, the sun fastness does not decline.
Source: Global Textile Web
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