Printing and dyeing cloth production practices to improve color fastness-Iota

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News > Dynamic industry > Printing and dyeing cloth production practices to improve color fastness

Printing and dyeing cloth production practices to improve color fastness

How to improve color fastness dyeing cloth, textile products to meet the increasingly fierce market demand, it has become a research and dyeing industry engineering and technical personnel.
Especially reactive dye colored fabric light fastness, deep color fabric wet rubbing fastness; hot disperse dye migration caused by wet fastness decline; and high chlorine fastness, perspiration - light fastness.
And many factors affect color fastness, color fastness improve methods, there are many ways I through years of practice, the choice of suitable dyes and auxiliaries, improved dyeing process, strengthen the process control, etc., to explore some methods and measures for colorfastness some improvement and improved, basically meet the market demand.
A light-colored fabric light fastness reactive dyes is well known in the dyed cotton fiber reactive dyes, in the sunshine from UV attack, dye structure chromophore or auxochromes, it would be subjected to varying degrees of damage, The cause discoloration or coloration, which produce light fastness problems.
China's national standard for light fastness of reactive dyes already have provisions, such as GB / T411-93 standard cotton dyeing cloth dyeing cloth light fastness reactive dyes is 4-5, calico light fastness grade 4; GB / T5326 standard combed cotton blended fabric dyeing and FZ / T14007-1998 cotton polyester blend fabric printing standards are prescribed, disperse / reactive dyeing cloth light fastness of four, calico is four.
Light-colored fabric dyeing reactive dyes to achieve this standard is more difficult.
Relationship between reactive dye 1.1 light fastness dyes and light fastness of the parent structure mainly related to the parent dye structures, 70-75% active azo dye parent structure, and the others as anthraquinone type, phthalocyanine type and Influenza.
Azo-type light fastness poor, anthraquinone, phthalocyanine type and armor of light fastness.
Yellow azo dyes molecular structure type, light fastness of color bodies with parent pyrazolone and naphthalene sulfonic acid-based three best blue spectrum of reactive dyes to anthraquinone, phthalocyanine, A parent structure, date excellent fastness sun, red spectrum activity azo dye molecular structure.
Light fastness is generally low, especially light.
Relationship dyed samples 1.2 light fastness and light fastness of the dye concentration will vary with the dye concentration is different samples with a dye in a dyeing of the same, with its light fastness increasing staining concentration increase, mainly due to the dye on the fiber aggregate particle size distribution caused by a change.
The larger aggregate particles per unit weight of the dye is exposed to the air - such as the role of water area is smaller, the higher light fastness.
Increasing the proportion of large aggregates of particles will increase in the concentration of dye on the fiber, light fastness also increased.
Low concentration colored fabric dyeing, dye aggregation on the lower body ratio of fiber, the majority showed a single dye molecule status, which is a very high degree of decomposition of the dye on the fiber, each molecule has the same chance of being light and air the role of water, light fastness corresponding decline.
ISO / 105B02-1994 standard light fastness standard assessment points 1-8, China's national standard is a standard assessment points 1-8, AATCC16-1998 or AATCC20AFU standard light fastness divided 1-5 standard assessment.
Therefore, we must be according to what standard, all dye manufacturers or companies, including dyed the color card "Colour Index" provided by the light fastness are dyed in the case to find out the depth of 1/1 of the determined customer requirements The data, which is measured on the dye concentration of about 20-30g / L data in colored fabrics, light-colored fabric is not up to this level.
1.3 Improvement of light fastness
1.3.1 affect the choice of fabric dye light fastness of colored dye itself is the most important factor, so use dyes are the most important.
Selection dye when mixed colors portfolio, be sure to make the choice of light fastness level of each component dye rather, as long as any one of the components, especially the least amount of light fastness components reach the light-colored dyed requirements, it will make a final light fastness of dyed not compliance.
C-Ciba Specialty Chemicals Inc. introduced, FN reactive dyes light fastness can reach 4 and above.
(1) the impact of the floating dye 1.3.2 other measures.
Dyeing soaping is not complete, not fixing dyes and hydrolysis residual dye in the fabric surface will affect the light fastness of dyed their lightfastness significantly lower than the fixing of reactive dyes.
Soaping were open more, the better lightfastness.
(2) fixing agent and softener effect.
Or low molecular weight cationic polyamine condensation resin type fixing agent and a cationic softener is applied after finishing, will light fastness of dyed decline.
Therefore, when the choice of fixing agent softener must pay attention to their effect on light fastness of dyed.
(3) Effect of the ultraviolet absorber.
UV absorbers has often been used to improve the light fastness of dyed light, but it must be a great amount of some effect, not only increase costs, but also cause yellowing and fabric strength loss, so it is best not to use this method.
2 reactive dyes deep color of wet fastness wet rubbing fastness of reactive dyes in recent years has been the difficulty and other dyes used.
Reactive dyes by covalent bonding impart excellent fastness dyed, but often dyed deep color fading and staining phenomenon occurs, these phenomena occur in addition to the parent structure of the part of the dye due to light, heat, sweat, acidic gas and oxidant erosion occurs azo group decomposition, complex metal ions from the amino oxide caused discoloration and fading dyed.
Dye - fiber bond cleavage can cause discoloration and staining.
The dyed fabric floating color is caused by deep color on the dyed fabric wash fastness.
2.1 All the floating dye dye after dyeing are left floating on the fabric dyes, reactive dyes floating color dye contains a partially hydrolyzed dye adsorbed on the fiber covalent reaction without participating dyes, these floating color dye Clear the extent to which they direct fibers, of which the largest is the immediacy vinyl sulfone-based dyes, followed by hydrolysis of dyes, dye due to the presence of water-soluble sulfur ester group, so a minimum of fiber unreacted immediacy, is the most easy to remove floating dyes, proved that even after a thorough water (soap) washing the fibers are still some remaining floating color dyes, reactive greater immediacy, the more difficult to remove the floating dye down from the fiber, but also has a water-soluble resistance, water will dissolve it came down, and up contamination to other fabrics, which are reactive dyes deep color fabric wet fastness including washing, soaping and wet rubbing fastness main reason for failure.
To clear the floating dye from the dye to consider two aspects of selection and process rationalization.
2.2 selecting dyes dyeing dyestuff selection is based on performance and sample test fastness dye color card to determine the level of wet fastness of the dye.
Because the color fastness card is at 1/1 dye concentration depth staining, only as a reference, but the latter dominated.
Thus, deep color dye dyed must be preferred to choose good fastness imported dyes, fixing rate is higher, better penetration dyeing.
2.3 Process 2.3.1 Precautions strengthen quality control, pre-treatment before treatment is mainly desizing, singeing, scouring and bleaching, mercerizing processes, and each process control will directly affect the quality and color fastness of dyed .
(1) Desizing Desizing must be fully drained away inside the fiber slurry, withdrawal does not affect the net dyeing levelness and dye penetration and hinder dye diffusion inside the fiber, the dye floating on the surface of the fiber affect color fastness degrees.
(2) singeing singeing to burn clean, singeing the net will not directly affect the finish and smoothness of the surface of the fiber, increase the friction coefficient, resulting in some resistance, reduced friction fastness.
(3), scouring and bleaching scouring bleaching to cooking, and meet the requirements of whiteness, to remove impurities and cotton seed hulls, up to standard capillary effect 8-10cm / 30min or more, mainly the capillary effect will directly affect the staining dye uptake and fixation rate.
Better capillary effect, dye penetration and levelness better, dye uptake and fixation rate is higher, the deeper the color yield, the less dye floating floating color surface, rubbing fastness and wash fastness as possible, both to save dyes costs, but also improve color fastness.
(4) silk satin fabric for dyeing is very important, in addition to silk fabric stable width size, but also can increase the depth of dyeing, improve gloss and smoothness of the surface of the fabric, improve the wet rub fastness and staining fastness, especially dyed dark fabric, silk is more important, it is necessary to control the alkali concentration of fine silk, satin achieve full effect.
2.3.2 Different staining methods preferred staining method, the depth of color yield, dyeing, dye penetration, the anchor effect is different, here are several different staining methods of analysis discussed.
(1) dip dip dyeing method, the fabric can have sufficient time at a certain temperature reacts with the dye, dye → diffusion → by adsorption on, to dyes and fibers sufficiently dye, dye penetration effect, and a higher fixation rate and vividness and color fastness.
(2) cold pad batch dyeing method is a fabric by cold-soaked pad liquid at room temperature and lye roll play, after a long period of slow rotation, after room stacked, rewound water, soaping, achieve full dye purposes.
This method is the best way to energy-saving, environmental protection, small batch production.
This method is a long time to fully absorb the dye and fiber to react, with good uptake rate, fixed rate, leveling and dye penetration, thus obtaining a good color fastness.
(3) Wet short steaming wet short steaming dyeing method is energy-efficient method of dyeing fabric directly after steaming pad by dipping liquid, solid color at high temperature and high humidity condition, so as to achieve rapid dye, fixing purposes with good dye uptake and penetration dyeing, color yield, bright color, you can get a good washing and rubbing fastness.
(4) There are two processes padding Padding France, one is rolling → bake → rolling → steam, the other is the roll → drying → steaming, the first one is the first re-rolling mill dye fixing solution, steaming That wet steam, to dye fixing purposes.
The second is padded with solid color bath after steaming and drying, the dry steam.
The depth of the latter than the former deep-dyed two percent, but lower than the former fastness, thus the former used more, but can not reach the depth of wet steam, dry steam can be considered, but in the use of solid finishing toner to improve the fabric fastness.
Fixing reaction is reactive dyeing most crucial stage, staining the whole process must be controlled in favor of fixing the hydrolysis reaction and inhibit direction, in order to get the highest fixing rate.
The more the amount of dye, the floating dye more and more, so in the reference standard dyeing depth of the premise, should be appropriate to the amount of dye, fiber adsorption of each dye has a limit, namely dyeing saturation value, generally do not exceed the saturation value of about 10%.
When the dye amount greatly exceeds the saturation value, the excess dye on the dye fixation can not only accumulate in the surface of the fabric, the impact of rubbing fastness.
And should use high lifting force reactive dyes, in the case of small amount of dye to achieve a high rate.
Several more stain from the fabric stained by color fastness after tests found preferably: dip> Cold Pad Batch> wet short steaming> rolling → bake → rolling → steam> rolling → drying → steaming.
2.3.3 washing treatment after dyeing the fiber interior and the surface has been fixing the dye, the floating dye, the residual alkali agent and electrolytes and other impurities, only these impurities cleaned to make dyed to achieve the best color fastness and color vividness .
The method relies on water, soaping and external mechanical forces, the purpose is to remove the hydrophilic floating color, wash away the electrolyte and alkali agent, reducing the concentration of the electrolyte in order to increase the electrostatic repulsion between the floating dye and fiber, so that the floating dye compared Easy from the fiber; wash off the alkali agent is to prevent the alkali agent causing the dye has been fixed at a high temperature hydrolysis in soap making.
Soap had boiled water is the removal of a large number of floating soap lotion dispersed dye.
After the process water quality is very important, if high water hardness, there would be more Ca2 +, Mg2 + and other heavy metal ions, which makes water soluble sodium salt water-soluble transition difficult calcium sulfonate (magnesium) color lakes, thus weakening the hydrophilic floating color dye, so the water quality of fastness after dyed product has a significant impact.
2.3.4 After finishing congenitally up, fabric color fastness after dyeing meet the requirements, but to use the fixing agent in the finishing and promotion agents make up and improve.
Special reactive dye fixing agent can make the deep color fastness to wet rubbing improve o.5-1.0 level.
3 Reactive Dyes chlorine fastness and perspiration - Light fastness chlorine fastness reactive dyes generally poor, depending on the molecular structure of color bodies, ortho diazo dye or a sulfonic acid group in the presence of a carboxylic acid group , or a hydroxyl group ortho coupling component or the presence of a sulfonic acid group or a para carboxylate group, because of its steric hindrance, reducing the attack -NH- or -N- CI- capacity, thereby increasing resistance to chlorine fastness.
According resistant to chlorine swimming pool water fastness test method GB / T8433-1998, the chlorine concentration divided into 200mg / L 20mg / L, 50mg / L and 100mg / L are three special requirements.
With the increase of chlorine concentration of chlorine fastness decline.
Therefore, it is important to select the dye, fixing agent may also be used a method in the finishing process improvement chlorine fastness, but can only improve from 0.5 to 1.0 magnitude.
Reactive dyes perspiration - received much attention in recent years light fastness, light fastness of some dyes well, but perspiration light fastness is poor.
Because the dual role of sweat and daylight fading different mechanism, since the sweat of amino acids or related material and metal complex dyes metal ion chelation, away from the dye precursor, complex light fastness dye precursors have been before well, so they fade or discoloration.
By comparison Preferably, Sumitomo's Sumifi SupraHF and NF series, Kayaku's KayacionE-LE series of dyes, perspiration - light fastness can reach 4-5.
4 disperse dye fastness and heat transfer and heat transfer phenomena caused by the decline is a redistribution phenomenon disperse two-phase solvent, so that all can dissolve disperse additives, can produce heat Transfer.
Thermal Transfer is due to the outer layer of the fiber additives at high temperatures to produce dissolution of the dye, the dye from inside the fiber by fiber capillary temperature and broaden migrate to the fiber surface, the dye deposited on the fiber surface, resulting in a range of effects , such as discoloration, contamination other fabric while ironing, abrasion, washable, perspiration, resistant to dry cleaning and color fastness to sunlight decreases.
Practice shows that the thermal dye directly related to migration within the fiber from the outer fiber and dyeing depth, the deeper the depth of fiber dyeing, the more the amount of dye and heat transfer from the inside out, the greater the impact on the dyed; high temperature treatment after dyeing for Mobility disperse heat greater impact, the higher the temperature, the greater the impact.
Therefore, when you try to use a mild dyed fabric finishing process.
Molecular structure itself disperse dye migration and related heat, we found wide application in the production practice of non-ionic surfactants, are the main cause of the migration phenomenon disperse heat.
Amino silicone softener emulsion as is currently the most used fabric softener, because microemulsion made is necessary to apply silicone 40-50% of the total amount of fatty alcohol ethoxylates or alkyl phenol ethoxylates and other non-ionic a surfactant as an emulsifier.
With the widespread use of amino silicone emulsion, disperse dye migration after the heat worse.
The solution is to choose a high lifting force and exhaustion, especially after dyed thermosetting with good wet fastness of disperse dyes.
By comparison, BASF's DispersoeXF series disperse dyed less prone to thermal migration, or hydrophilic amino brick oil, no emulsifiers, dyed and heat transfer phenomena reduced.
Attached to the fiber surface of the dye (floating) will increase the impact of color fastness of dyed fabrics produced by thermal dye migration.
Thus, stained (especially dark) should be used to restore a reducing agent and an alkaline agent cleaned to completely remove floating color.
5. Conclusion
In summary, to improve color fastness of dyed, dye choice is very important to the requirement for color fastness to select different dyes, high demands for light fastness to choose light-colored fabric dyes and a high light fastness of reactive dyes for dyeing; deep color only selection fixation rate, high lift force importing reactive dyes to ensure the wet fastness; disperse to select a smaller thermal dye migration, especially dark should Try to avoid staining saturation value reached or exceeded, the use of surfactants should adhere to the "can not do it, you can use less and less use, non-use can not, we should carefully choose" principle.
In the production management process, be sure to strengthen the process control in order to guarantee the achievement of the following process requirements: (1) fiber surface to be smooth, less hairiness.
(2) The gross effect of fiber to be higher.
(3) color absorption capacity of fiber stronger.
(4) The dye penetration degree of fiber dyeing dye better.
(5) dyes and fibers are bonded to fully fixed.
(6) after dyeing soaping wash thoroughly.
Level off key processing Dye (7) was small.

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