Brief Talking about Color Fastness

Color fastness, also known as color fastness or dyeing fastness, refers to the degree of fade of the dyeing fabric under the effect of external factors (such extrusion, friction, washing, rain, exposure, light, Saliva dripping, water stains, perspiration, etc.) in the use or processing process.

Color fastness is a very important reference indicator for dye products. If color fastness is good, the textile is not easy to fade in the post-processing or use process; if color fastness is poor, textile will fade seriously, colored slightly, or stain, which will affect the appearance and cause a lot of inconveniences.

The common questions of about color fastness  

1. Color fastness to sunlight
The parts of clothing like coat under sunlight will fade or discolor (usually the back and shoulder parts) while other parts don not, resulting in different parts of the product looks different so that the product cannot be used.

2. Color fastness to water cleaning, soaping, and dry cleaning 
This problem would likely to exist in advanced silk clothing, wool clothing, cotton clothing.

3.Color fastness to rubbing
During using, because the degree of friction different parts of clothing is different, the degree of fade is different. For example, the elbow, collar, and armpit of shirt or sleeves are most likely be faded. In addition,  buttocks and knee parts of pants are also easy to fade.

4. Color fastness to perspiration 
Mainly because clothing will fade owing to the sweat in summer.

Factors that affect color fastness

Factors affecting the color fastness of textiles can be divided into internal factors and external factors. Internal factors refer to the firmness of the combination of dyes and fibers. External factors refer to the external forces or the environmental conditions which the external factors produced during the use of the product. External factors sometimes can not be controlled, so producers should strive to improve the color fastness of the product itself.
 

Improvement of color fastness

1. Selection and use of dye materials
Dye material is very important to the color fastness of a product. If the dye material is not appropriate, no matter how good the process is, there is no way to dye high-quality color fastness. Only if you choose the right dye, the next step can continue.
More meticulously, you can choose dyes from many aspects such as the characteristics of fiber, the depth of color, the color fastness of the dye itself, the dyeing rate of the fiber, the good compatibility between the dyes, the number of dyes required to reduce and so on. It is very useful for the next step.

2. The selection and use of auxiliaries 
After determining the kind of dyes, choosing auxiliaries is also very important. Generally try to choose supporting auxiliaries to dyes, if choosing ordinary dyes, you have to focus on the use and the amount of auxiliaries. For dark colors, the dye is not easy to exhaust, so you can add the auxiliaries in batches to improve the utilization. Improving the durability of dye adsorption can also play a role in fixing.

3. Make dyeing process  
Dyeing process is the key link in dyeing. When making dying process, the determination of dyeing time, heating rate and holding time must be based on dyes and products. For light color, the heating rate must be slow and the holding time can be shorter; for dark color, the heating rate can be fast, but the holding time must be sufficient, so that the dye and fiber can be fully combined to achieve the purpose.

Take fastness products as examples:

Wet Rubbing Fastness Improver Agent 809

Original wet rubbing fastness improving agent is poor deep dyeing for direct, reactive, indigo blue and sulfur dyestuffs, especially for dark black, bright red and turquoise blue whose wet rubbing fastness is below Grade 1, while fabric wet rubbing fastness exported to Europe and US must be above Grade 3. Therefore, our company specially developed environment-friendly wet rubbing fastness improving agent 809 that improve the product stability of salt & alkali and reduce the structure insufficient of the product.

【Main composition】 Special water-based polyurethane.

【General properties】

Appearance: light yellow to yellow liquid（darker as time going）

Ionicity: weakly cationic

pH: 5±1（50g/L）

Solubility: easily soluble in normal water in any proportion at room temperature

【Product features】

1. Free of formaldehyde and APEO that belongs to environmental products and complies with EU OEKO-TEX Standard 100 requirements.

2. Use for fixing after cellulose fibre dyeing .Excellent wet rubbing fastness improving performance that can meet above Grade 3 by improving 1- 1.5 grades .

3. Easy operation for using by direct dilution.

4. Soft hand feeling, no influence on light fastness and resistant to washing.

【Application】

Based on different kind and concentration of dyes, different kind and pattern of treated fabric, Dosage as below:

1. Dipping (washing only)

HT-809:    2-4% (O.W.F) (Adjustment base on color)

Bath ratio: 1: 10 – 20

Dyed fabrics (pH ≦ 7) → Dip at 40℃ × 20 – 30 min →Dry

2. Padding:

HT-809:    30 – 50 g/L

Dyed fabrics (pH <= 7) → One dip & pad with water retention 80 – 85% → Dry

Wet Rubbing Fastness Improving Agent HT-818

Brief information】

-- Original wet rubbing fastness improving agent is poor deep dyeing for direct, reactive，indigo blue and sulfur dyestuffs, especially for dark black, bright red and turquoise blue whose wet rubbing fastness is below Grade 1, while fabric wet rubbing fastness exported to Europe and US must be above Grade 3. Therefore, our company specially developed environment-friendly wet rubbing fastness improving agent 818 that comply with the new environment requirement, such as free of DMF solvent, few odor.

【Main composition】

-- Special water-based polyurethane.

【General properties】

-- Appearance: light yellow to yellow liquid（darker as time going）

-- Ionicity: weakly cationic

-- pH: 3.5+0.5（50g/L）

-- Solubility: easily soluble in normal water in any proportion at room temperature

【Properties and fields of application】

-- Free of formaldehyde and APEO that belongs to environmental products and complies with EU OEKO-TEX Standard 100 requirements.

-- Use for fixing after cellulose fiber dyeing. Excellent wet rubbing fastness improving performance that can meet above Grade 3 by improving 1- 1.5 grades.

--No influence on shade and light fastness.

--It is obviously to improve the stability, such as resist to salt and hard water.

【Application】

Based on different kind and concentration of dyes, different kind and pattern of treated fabric, Dosage as below:

-- Dipping (washing only)

HT-818:   2-4% (O.W.F) (Adjustment base on color)

Bath ratio:   1: 10 – 20

Dyed fabrics (pH ≦ 7) → Dip at 40℃ × 20 – 30 min →Dry

-- Padding:

HT-818:   30 – 50 g/L

Dyed fabrics (pH <= 7) → One dip & pad  with water retention 80 – 85% → Dry

Heat Sublimation Fastness Improving Agent RB

【Brief information】

1.Due to oxygen in the air under the catalysis of light, and the disperse dyes of fabric have the reaction between polyester fibers and chemical agent that results in yellowing, color change; or disperse dye color becomes shallow under the action of heat sublimation. We call the decline of sublimation fastness is heat migration fastness.

2.Textile products widely use a lot of non-ionic surfactant type amino silicone micro emulsion softener that results in decline of sublimation fastness. So we can use a special heat sublimation fastness improving agent (also call polyester fixing agent) before padding to prevent decline of heat sublimation.

【Main composition】 Special polyion compound

【General properties】

Appearance: yellow transparent liquid

Ionicity: cationic

pH: 3-5

Solubility: soluble in water

Stability:             resist to acid, alkali and electrolyte

【Product features】

It can improve the hot sublimation fastness when use in disperse dyes. Excellent effect on the washing fastness and have little influence on fabric shining.

【Application】

Padding:   30-50 g/L

Dipping；  3-5%（o.w.f） Stoving and padding after dipping.

【Packaging and storage】

125 kg/ polyethylene drum, 12 months in sealed container.