Dyeing properties of small pattern suede fabric

- Jul 16, 2018-

Suede fabrics are processed from microfiber fabrics. Because of its soft, smooth, delicate, drape, suede, comfortable wearing, and good wear resistance, it is favored by consumers.

At present, there are many varieties of suede fabrics on the domestic market, but the fabric style and dyeing quality are quite different. Due to the large surface area of the ultrafine fiber and the large amount of adsorbed dye, it is easy to cause poor dyeing, low color fastness and uneven dyeing. The style and color fastness requirements of suede fabrics in foreign countries are generally high, and many domestic enterprises cannot meet the requirements. Therefore, these problems have been plaguing many textile printing and dyeing enterprises.

Based on the structural characteristics of the island-type composite superfine polyester yarn, on the basis of exploring the reduction treatment of the suede fabric, the small pattern suede products with different pattern effects were designed and developed. Dyeing performance, discussion on dyeing temperature, time, dye lift and dye fastness.

1 experimental part

1.1 Materials

Small pattern suede fabric, warp and weft density is 620 pieces/10cmx300 pieces/10cm, width is 160cm; warp material: 116.7dtex/36f polyester island silk (37 islands); weft material: 222.2dtex/96f polyester DTY, before The weight loss rate of the treated fabric was 18.79%, and the areal density was 217 g/m2.

Disperse red ERD, disperse yellow ERD, disperse green ERD, disperse golden E3RL, disperse brilliant blue E4R, disperse red E4R, all industrial grade; ammonium sulfate, analytical grade; sodium acetate, analytical grade; caustic soda, industrial grade; soda ash, Industrial grade; CE100 chelate dispersant, industrial grade.

1.2 Instrument

XW-HGL-12 infrared dyeing machine; FA2104SN electronic balance; 721 spectrophotometer; L-12-20-24A-2Z oscillation color tester; electric blast drying oven; PHS3C acidity meter; Datacolor600 color measurement color matching system.

1.3 method

1.3.1 Determination of dyeing rate of disperse dyes

Pipette each 1 mL of the dye solution before and after dyeing into a 10 mL volumetric flask, add acetone to the mark, and measure the optical density D1 and D2 of the dye solution at the maximum absorption wavelength with a 721 spectrophotometer.

Percentage of dyeing = (1-D2V2/D1V1) x 100%

Where: D1 is the optical density of the dyeing solution before dyeing; D2 is the light density of the dyeing solution after dyeing

Degree; V1 is the volume of the dye solution before dyeing; V2 is the volume of the dye solution after dyeing.

1.3.2 Determination of the amount of dye in the fiber

Different concentrations of dye solutions were prepared by using N, N-dimethylformamide solvent, and their optical densities were measured at the maximum absorption wavelength, and the working curves of dye concentration and dyeing optical density were determined.

Weigh 0.0500g of the dyed sample, add it to a small amount of N, N dimethylformamide solution, and heat until the dye on the sample is completely extracted. Transfer the solution to a 25mL volumetric flask and add N, N dimethyl Formamide was added to the mark, and 5 mL of the solution was transferred to a 25 mL volumetric flask. The optical density of the solution was measured at the maximum absorption wavelength, and the dye concentration was obtained from the dye concentration and the optical density curve to calculate the amount of the dye in the fiber.

1.3.3K/S value determination

The K/S value of the dyed fabric was tested using a Datacolor 600 color matching system.

1.3.4 Evaluation of color fastness

1) Color fastness to washing according to GB/T3921.31997eqvISO105-C03:1989<<Spinning

Color fastness test of fabrics - Wash fastness: Test 3>> The sample was tested for wash fastness on a SW-12 wash fastness tester.

2) Color fastness to rubbing

The samples were tested for rubbing fastness according to GB/T39201997 eqvISO 105-X12:1993 <<Determination of rubbing fastness of textile color fastness test on the Y571B rubbing fastness tester.

3) Sublimation color fastness

According to GB/T57181997eqvISO105-P01:1993<<Textile color fastness test dry heat resistance (except hot pressing) color fastness on the YG (B) 605 type ironing sublimation color fastness tester Fastness test, temperature is (180 ± 2).

2 results and discussion

2.1 Temperature dependence of disperse dyed suede

Two types of 6 dyes were used, namely disperse red ERD, disperse yellow ERD, disperse green ERD, disperse golden E3RL, disperse brilliant blue E4R and disperse red E4R at a mass fraction of 2% (owf) and ammonium sulfate mass concentration. 1g / L, with glacial acetic acid to adjust the pH to 5, the bath ratio of 50:1, the temperature of the suede dyed at different temperatures for 1h (100 ° C and 100 ° C or more, due to the temperature rise process, so the temperature is 100 ° C for 45 min The temperature was 42 min at 110 °C, 38 min at 120 °C, 36 min at 125 °C, and 34 min at 130 °C. Then the dye uptake and K/S values were measured. The test results are shown in Figures 1 and 2.

It can be seen from Fig. 1 that when the dyeing temperature is lower than 70 °C, the dye uptake rate of several dyes does not change significantly, and the dye uptake rate is low. As the temperature increases, the temperature is higher than the glass transition temperature of the polyester fiber. The dye uptake rate of dyes is obviously improved. When the temperature reaches 110~120 °C, the dye uptake rate of various dyes reaches the maximum value, the temperature increases further, and the dye uptake rate decreases. When suede is dyed with disperse dyes, the highest dyeing temperature should be 10-20 ° C lower than the highest dyeing temperature (130 ° C) of conventional polyester fabrics. The reason may be the difference in the supramolecular structure between the island-type superfine polyester fiber and the ordinary polyester fiber. Compared with ordinary polyester fiber, the island-type superfine polyester fiber has low molecular orientation, high amorphous content, and no obvious cortical structure. The molecular chain has a higher probability of relative slip at the same dyeing temperature. The pores are more easily formed, so the dyeing rate of the island-type ultrafine fibers is high, and the dyeing unevenness is easy to occur, especially at high temperature (130 ° C), and the desorption rate of dye molecules at high temperature is high. The dyeing rate is greatly increased, even exceeds the adsorption rate, so that the dye which has been adsorbed onto the fiber is detached from the fiber, and thus the dyeing rate is lower than that at 110 to 120 °C. Therefore, the dyeing temperature should not be too high, and the heating rate should not be too fast, which is beneficial to the fixing of the dye and the improvement of the dyeing fastness. It can be seen from Fig. 2 that the K/S values of the other five dyes are maximal at 110 °C except for the dispersion of the green ERD at a temperature of 120 ° C, which also indicates the suede fabric. The highest dyeing temperature is 110~120 °C.

2.2 Lifting dyes enhance the dyeing of suede

Pipette 0.1g/L of dispersed red ERD mother liquor 25, 20, 15, 10, 5, 2.5mL into a 50mL volumetric flask, add N, N dimethylformamide to the scale, and press 1~6 sequential numbering. The dye with the intermediate concentration is selected to measure its maximum absorption wavelength (λmax) on a spectrophotometer, and then the absorbance of each dye solution in the volumetric flask No. 1 to No. 6 is measured at this wavelength, as shown in Fig. 3.

The suede was dyed with disperse red ERD of different mass fractions at a rate of 3 ° C/min in the case of ammonium sulfate of 1 g / L, pH adjusted to 5 with glacial acetic acid, and bath ratio of 50:1. The temperature is raised to 50 ° C, then raised to 90 ° C at a rate of 1 ° C / min, held for 20 min, then heated at a rate of 1 ° C / min to 120 ° C for 50 min, and then dropped to 70 ° C at a rate of 1 ° C / min; Finally, it was washed with 2 g/L of Na2CO3 and 2 g/L of detergent for 20 min at 80 °Cmin. The K/S value and dye content of the fabric were then determined, and the results are shown in Figures 4 and 5, respectively.

It can be seen from Fig. 4 that the mass fraction of the dispersed red ERD increases from 1% (owf) to 14.0% (owf), and the dyeing amount of the dye in the suede rises linearly from 10 g/kg to 113.5 g/kg. However, after the dye mass fraction reaches 14% (owf), the dye uptake rate tends to be gentle as the dye mass fraction is further increased. This shows that the disperse dye has a good improvement on the dyeing of the suede fabric. It can be seen from Fig. 5 that the K/S value of the suede fabric also increases with the increase of the dye amount, but the increase rate of the K/S value is slowed down when the mass fraction of the dye reaches 12.0%.

2.3 Dyeing process of small pattern suede fabric

Since the surface area of polyester microfibers is much larger than that of ordinary polyester fibers, the speed of dye adsorption from the dye bath is much faster, and there is a more obvious dyeing at low temperature (40~50 °C), so at low temperature (40) The heating rate should be strictly controlled within the ~50 °C) region. In addition, since the microfiber has a large specific surface area and a surface which is not smooth, the adsorption rate is much higher than that of the conventional fiber, and the latitude and longitude difference of the suede fabric is large, resulting in poor leveling property. According to the literature [introduction, in the 90 ~ 95 ° C area for a certain period of time has a good leveling effect. In addition, during the heating process, the dye is dyed at the same time as the dyeing, and the heating time is prolonged. Although it is not kept at a certain temperature, during the heating process, the dye is dyed at the same time, and the dyeing is slowed down. The heating rate can achieve uniform adsorption on the one hand, and strengthen the transfer dye on the other hand, which is beneficial to leveling.

It can be seen from the experiment that the suede fabric has the highest dyeing rate and K/S value at 110~120 °C, so the maximum temperature of the suede fabric is 110~120 °C. At the same time, in order to increase the leveling and color fastness indicators, it is necessary to keep warm for a certain period of time.

Special attention should be paid to the process and formulation: 1) Properly reduce the initial dyeing temperature and control the dyeing rate; 2) Strictly control the heating and cooling rate; 3) Control the high temperature holding time to improve the leveling; 4) Add the appropriate amount High temperature disperse leveling agent to increase leveling; 5) Add appropriate amount of softener in the bath to prevent wrinkles and scratches the fluff; 6) In order to increase the color fastness, carry out reduction cleaning.

Through experiments and analysis, the formula of the small pattern suede dyeing process was determined as: disperse dye x% (owf); chelate dispersant 1g / L; leveling agent 1g / L; bath softener 1g / L; with glacial acetic acid The pH was adjusted to 5; sodium acetate 1 g/L; bath ratio 1:20.

2.4Reduction cleaning process of small pattern suede fabric

In order to improve the color fastness of the small-pattern suede fabric, an appropriate reduction cleaning is also required. Reduce cleaning formula and process: add 2g/L sodium carbonate and 2g/L detergent, heat up to 80°C at 3°C/min, keep warm for 20min, then cool down to 70°C at 3°C/min, then use warm water Fully cleaned. The dyeing process and the reduction cleaning process curve are shown in Fig. 6.

Color fastness of 2.5 small pattern suede fabric

The dyeing fastness of the fabric measured after dyeing the small pattern suede fabric and the reduction cleaning process determined by 2.4 according to the dyeing process determined in 2.3 are shown in Tables 1 and 2. It can be seen from the data in the table that the small-pattern suede fabric treated according to the 2.3 dyeing process and the 2.4 reduction cleaning process can obtain better effects in terms of washing fastness, sublimation fastness and rubbing color fastness.

3 conclusions

1) The dyeing process of small pattern suede fabric has a high dependence on temperature. It is necessary to reduce the initial dyeing temperature and control the heating rate. The best dyeing process is: start dyeing at 40~50°C, then slowly heat up to 90. The dyeing was carried out for 20 min at °C, and then slowly heated to 110~120 °C for 50 min.

2) In the dyeing process, an appropriate amount of high-temperature dispersing leveling agent and softener in the bath should be added to increase the leveling property, prevent the fabric from wrinkling, scratch the fluff, and affect the fabric style.

3) In order to increase the color fastness, it is necessary to carry out reduction cleaning. The suitable reducing cleaning liquid composition is: 2g/L sodium carbonate and 2g/L detergent, and it is reduced and cleaned at 80 °C for 20min.

4) Dyeing according to the best dyeing process, after the reduction and cleaning, the fabric can obtain higher color fastness.

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