Four properties of disperse dye leveling agent

Disperse dyes are non-ionic dyes with low water solubility. Generally, high temperature and high pressure are used for dyeing. In order to achieve uniform dispersion and dyeing, leveling agents are generally used in the dyeing process. Today, I will talk about the choice of disperse dye leveling agents.

Slow dyeing

The slow-dyeing property of the leveling agent can suppress the instantaneous dyeing in the early stage of dyeing, which is the primary factor in choosing the leveling agent. The test method of slow staining is generally as follows:

1. Experimental materials:

Sample: polyester fabric after degreasing and refining

formula:

C.I. Disperse Orange 30# 0.5% (O.M.F)

C.I. Disperse Red 60# 0.5% (O.M.F)

C.I. Disperse Blue 79# 0.5% (O.M.F)

Levelling agent x g/L

pH: 4.5

Bath ratio: 1:20

2. Experimental technology:

Stock solution dyeing: dyeing at 40℃, 30min heating up to 130℃, dyeing for 45min, sampling 6 times at 90℃, 100℃, 110℃, 120℃, 130℃, 130℃×45min, half of the cloth sample taken out is reduced and washed (Sodium hydroxide 2g/L, NaOH 2g/L, 80℃×20min), the other half is rinsed with tap water for about 30s and dehydrated and dried.

Residue dyeing: After each sampling, measure 40mL of dyeing residue and add 2g polyester cloth for dyeing. The process is the same as above.

3. Result evaluation:

The more even the color gain between the dyed samples at each sampling point, the lighter the relative color, indicating the better the retarding effect of the leveling agent.

Migration

Dye migration is a process in which the leveling agent re-disperses the high dye concentration part of the dyed fabric into the dye bath, and then dyes the low dye concentration part. Dye migration is an important performance of the disperse dye repair agent. 

Regarding migration, the following methods are generally used for testing:

1. Experimental materials:

Dyed polyester fabric: red (Un-se Red 0.5%) + yellow (Un-se Yellow 0.8%) + blue (Un-se Blue 0.5%) + undyed polyester fabric each, four fabric sheets Edge stitching forms a set.

formula:

Levelling agent x g/L

pH 4.5-5

Bath ratio 1:20

2. Experimental technology:

Dyeing at 40°C, heating to 130°C for 30min, transfer dyeing for 60min, take out the cloth sample, wash with water and dry.

3. Result evaluation:

The closer the color of each color sample in the combination after migration, the better the migration effect.

Achromaticity

For disperse dye leveling agent or color repairing agent, while achieving good retardation and migration effects, the smaller the decolorization, the better the performance of the auxiliary. The test method for decolorization is recommended as follows:

1. Experimental materials:

Sample: 4g polyester knitted fabric after degreasing

formula:

Levelling agent x g/L

C.I. Disperse Blue 79# 0.05% (O.M.F)

pH: 4.5

Bath ratio: 1:20

2. Experimental technology:

Dyeing at 40℃, heating to 130℃ for 30min, dyeing for 60min, take out the cloth sample, wash with water, and dry.

3. Result evaluation:

Using the blank (no levelling agent) dyed fabric sample strength as the standard sample, determine the color strength and color difference DE (also visually detectable) of the dyed fabric sample under different leveling agents (color correction agents) and dosage conditions, the higher the strength , The smaller the color difference, the less the color reduction.

Dispersion

Dispersibility is also one of the necessary conditions for a good leveling agent for disperse dyes. The dispersibility of the leveling agent can avoid the agglomeration of the dye during the dyeing process (generally, a dispersant is added in the production process of disperse dyes). The following is the leveling agent dispersion A test method of sex:

1. Experimental materials:

formula:

C.I. Disperse Red 167# 1.0g/L

Levelling agent x g/L

pH 4.5

Total liquid volume 100mL

2. Experimental method:

Dye liquor heat treatment: heat the dye liquor to 130°C for 30 minutes, and then lower the temperature to 70°C at a rate of 2°C/min.

Dye liquor filtration: first preheat the Buchner funnel with 70℃ hot water and dry it with a towel, then stack the medium-speed qualitative filter paper on top of the fast qualitative filter paper, put it in the funnel, turn on the vacuum pump, and transfer the dye liquor at 70℃ Pour into the funnel. When the appearance of the filter paper changes from wet to dry, it is the end point. Take out the filter paper and dry the upper layer of filter paper for evaluation.

3. Result evaluation:

Visually inspect the dye precipitation on the filter paper, the less the dye color point, the better the dispersion.