The three-color lace elastic fabric is developed with four kinds of fibers, namely rayon, nylon filament, modified polyester filament and lycra. According to the dyeing properties and characteristics of the fibers, the dyeing and finishing process is formulated, including washing water to remove oil, fixed blank, dyed rayon, nylon filament, modified polyester filament in one bath dyeing, and finished product setting. The production practice shows that the dyeing effect is ideal, the size is stable, and the performance tests can meet the requirements of customers.

Lace fabric is the favorite of women's clothing elements. It has a mysterious and elegant artistic effect due to its thin and transparent material texture, and is widely used in women's intimate clothing. At present, there are various types of lace in the market, most of which are made of one or two kinds of fibers. However, the elastic lace fabric made of three or more kinds of fibers can be dyed with three or more colors through reasonable dyeing and finishing process, which can achieve rich and colorful colors and strong visual effects with a strong sense of layering, giving the lace features such as high-grade, fashionable, exquisite, rich layers and different styles.

The elastic fabric described in this paper is made of rayon fiber, polyamide filament, modified polyester filament and lycra woven by Jaca machine. Dyeing and finishing of elastic lace fabrics woven with various fibers is a complex and skilled project. It is necessary to develop a reasonable dyeing and finishing process according to the characteristics and properties of the raw materials used, dyeing and chemical materials, and fully reflect the high quality and high grade of elastic lace fabrics.

1. Properties and characteristics of fabric fibers

Rayon fiber has excellent performance in moisture absorption and air permeability, with smooth cool, breathable, antistatic, gorgeous dyeing and other characteristics, because of good moisture absorption, comfortable wearing, often mixed with a variety of synthetic fibers used in all kinds of clothing and decorative textiles, good dyeing performance, can obtain bright color, can be dyed with reactive dyes.

Nylon silk has the advantages of high strength, good wear resistance and high elasticity. It is more suitable for the production of lace fabrics with high tensile force and strength requirements of yarn, and is generally dyed with acid dyes.

The modified polyester filament used is the normal pressure cationic dyeable polyester. It has high fiber strength, good impact resistance, heat resistance, rot resistance, cavity resistance, acid resistance, easy to wash and dry, and good shape preservation.

With the increase of the fourth monomer content of the modified polyester filament, the fiber can increase the activity of the chain segment of the dimensional macromolecule, improve the degree of plasticizing and expanding, make the fiber structure more relaxed, and greatly reduce the dyeing temperature. It can be dyed with cationic dyes under atmospheric pressure to reduce energy consumption and improve the utilization rate of dyes.

Lycra fiber as a kind of elastic fiber with good tensile recovery, can give fabrics excellent elasticity, depending on the leakage of Lycra white, use a small amount of disperse dye or spandex coloring agent dyeing.

The lace elastic fabric woven with the above four kinds of fibers has the advantages of light weight, bulk, softness, comfort and durability, and has good wear performance.

2. Study on dyeing and finishing processing methods

2.1 Dyeing and finishing process

The ratio of materials used is: rayon 15%, nylon filament 44%, modified polyester filament 32%, Lycra 9%.

According to the properties and characteristics of the fibers, selecting the appropriate dyes and dyeing processes to dye rayon, nylon filament and modified polyester filament is the focus of this paper. Acid and cationic dyes can be used for the dyeing of nylon filament and modified polyester filament, and good two-color effect can be achieved by one-bath dyeing by controlling appropriate dyeing conditions.

Use predetermined shape and finished shape to stabilize the fabric specification. According to the fiber structure and performance of the fabric, the dyeing and finishing process is formulated as follows: grey cloth oil removal → predetermined shape → dyeing (rayon first, nylon filament/modified polyester filament) → finished product shaping → inspection.

2.1.1 Remove oil from grey cloth

Because the fabric contains more chemical fibers, with a variety of oils, if it can not be removed evenly, it will lead to horizontal stripes, uneven dyeing, cloth stains and white spots and other defects, so it is necessary to use oil removal agent treatment before dyeing.

Grey cloth deoiling is generally carried out in the continuous open width deoiling machine, the process conditions should be soft, the neutral deoiling agent LYS can be used, the temperature should not exceed 80℃, grey cloth in the deoiling process without tension completely relaxed, can make the fabric size stable, left, right, head and tail everywhere gram quality is consistent.

2.1.2 High temperature preforming

Preshaping utilizes the thermoplasticity of nylon filament, modified polyester filament and lycra to eliminate or reduce the unevenness of tension generated in the spinning drafting and weaving process, avoid excessive relaxation of fiber in the subsequent process, improve the supramolecular structure of fiber, so as to improve the stability of fabric shape.

The higher the predetermined shape temperature is, the higher the dimensional stability of the fabric is, and the more effective it is for improving the crease. However, too high temperature will also lead to greater elastic loss of the fabric. Specifically, the predetermined shape process should be reasonably formulated according to the thickness specifications and Lycra size of the fabric, so as not to damage the fiber, but to ensure the dimensional stability and smoothness of the fabric.

The preset temperature we used was 190℃ and the time was 25 ~ 30 seconds.

2.1.3 Dyeing

Because rayon/nylon filament/modified polyester filament/Lycra are free of natural impurities and have good whiteness, it can be dyed directly without pretreatment before dyeing.

a. Dyeing rayon technology

Take dark green/rose/pink/for example, rayon dyed dark green.

Rayon dyeing process prescription and conditions

Prescription and conditions (bath ratio 1:10):

Active yellow HE4R 0.121%

Reactive blue H-EGN 0.205%

Na2S04                     50 g/L

Na2C03                     15 g/L

Softening agent PA 1.0g /L

Penetrant JFC L.0 g/L

Heating rate 1.O℃/min

Holding time 80℃×30 min

b. Dyed polyamide filament/modified polyester filament

Nylon filament dyed rose, modified polyester filament dyed pink.

Dyed polyamide filament/modified polyester filament dyeing process

Prescription and conditions (bath ratio 1:10):

Acid red RLS 0.0585%

Acid yellow PA-1 0.0103%

Acid Blue PA-1 0.014%

Cationic (red) GRL 200% 0.0012%

Cationic (yellow) GL EC 400% 0.0083%

Cationic (blue) GRL 300% 0.0052%

Water absorbent TM 2.0g /L

(NH4)2S04 2.0g /L

Acid levelling agent AD 0.60g /L

Anion retarder M 1.0%

Antiprecipitation agent S 1.0%

Acid HAc/NaAc l/0.5

Holding temperature x time 98℃ x 30 min

The function of softener CN is to reduce the friction coefficient between fabric and equipment, so as to reduce the production of fabric scratches and creases. The absorbent agent TM is added to the fiber in the dye solution for water absorption and perspiration treatment, increasing the water absorption and perspiration function of the fabric.

c. Post-processing condition

Soap prescription and Conditions:

Soap Lotion DM l.0%

Insulation temperature x time 55℃ x 10min

Color fixing prescription and conditions:

Acetic acid 1.30g /L

Color fixing agent NT 3.0g /L

Holding temperature x time 70℃ x 30 min

2.2.4 Finished product setting

The shape of the finished product is an important link in the dyeing and finishing process of the fabric, which can further stabilize the fabric size and eliminate the slight creases and wrinkles produced in the dyeing process.

Due to the predetermined type, fabric fabric door width, gram quality and other physical indicators, fabric size is basically stable. When the finished product is set, according to the customer's requirements for fabric fastness and feel, a certain amount of deodorant, bactericidal agent, color fixing agent can be added to the shaping slurry, and appropriate amount of softener and hydrophilic agent can be added to give the fabric better softness, moisture absorption and other wearing comfort. However, attention should be paid to the ionic property of the setting agent, so as not to produce slurry pollution.

Formulation of setting slurry:

Antibacterial agent DA 35 g/L

Deodorant FT 15g /L

Absorbent Soft oil N 20 g/L

Citric acid 0.3g /L

Setting condition: 150℃×10s, machine speed 30m/min.

Determination of the setting temperature: because the critical temperature of cationic dye color change is about 140 ~ 150℃, too high or too low temperature will not make the fabric to obtain excellent performance, and Lycra fiber is very sensitive to the setting temperature, time, temperature is too high, time is too long fabric elasticity will be reduced. Therefore, for the sake of safety, the setting temperature is selected at about 150℃, and the setting can not be stopped in the middle, so as to avoid the color change of the fabric due to the inconsistent setting time.

3. Influence of dyeing process conditions on dyeing quality

3.1 Selection of rayon dyes

The Procion HE type produced by ICI is a high temperature reactive dye specially suitable for dry dyeing. It has excellent color brightness, dyeing economy, good dyeing uniformity and excellent color matching performance. In order to prevent the polyamide silk from staining, it can be selected to add soda ash first, then add sodium powder for 20min, and then add reactive dye for dyeing. The holding time can be changed with the amount of dye.

3.2 Dyeing process of polyamide filament/modified polyester filament

3.2.1 Dyeing sequence of adding dyes

When acid dyes are used for polyamide silk dyeing, the proper initial dyeing temperature, temperature rise rate and dyeing time should be controlled according to the size of the dye's aggregation tendency, diffusivity and dyeing performance, so as to achieve the purpose of evenness and penetration of dyeing.

Cationic dyes have a large affinity for modified polyester filament, which is easy to produce uneven dyeing due to fast adsorption and slow diffusion during dyeing. Once uneven dyeing occurs, it is difficult to correct by extending the dyeing time.

Due to the opposite ionic property of acidic dyes and cationic dyes, the dyeing order must be attached importance in the formulation of the process, so it is dissolved separately, and the anionic retarding agent M and the antiprecipitation agent S are added to achieve the effect of leveling the dyeing.

Generally, one-bath two-step dyeing method is used, which needs to take into account the different characteristics of dyes and materials to develop a process, adding acid dyes first, adding cationic dyes, and then heating up in the same bath dyeing modified polyester.

3.2.2 Temperature

Temperature is an important factor to control evenness. Due to acid dyes dyeing nylon from 40℃, some began to dye, and modified polyester filament with cationic dye dyeing, at 70℃ below the amount of dyeing is very little, when the dyeing temperature reaches the fiber glass temperature (70-85℃), the dye dyeing rate began to increase rapidly. Therefore, we select the dyeing process, strictly control the temperature rise rate, step by step temperature rise, to ensure the dyeing effect.

3.2.3 Dyeing bath pH value control

Acidic dye and cationic dye dyeing pH value is generally 4-5, generally adjusted by acetic acid, adding ammonium sulfate or sodium acetate in the dyeing bath at the same time, stable dyeing bath pH value in the required range, can also be used to slow acid to obtain a stable pH value.

3.2.4 Use of levelling agent, retarding agent and anti-precipitation agent

Acid leveler AD is added in acid dye dyeing, so that the nylon silk dyeing uniform, before adding cationic dye added anionic retarder M, because of the use of anionic retarder M, cationic dye and anionic dye can be dyed in the same bath, creating conditions for acid dye Yang/ion dye one-bath dyeing.

Anion retarding agent M is added to make it combine with cationic dyes to form complex i with low solubility suspended in the dye bath, which has a small affinity for fibers, reducing the concentration of free cationic dyes and slowing down the dyeing rate of dyes. With the increase of dyeing temperature, the complex gradually decomposes and releases free cationic dyes, which gradually increases the dyeing rate. So as to achieve the purpose of leveling.

In order to avoid complex precipitation, anion retarder M and antiprecipitation agent S should be added at the same time.

4. Product performance test

The dyeing effect and quality of the products were tested by mass production with the above technology.

As can be seen from Table 1 and Table 2, the product has good color fastness and dimensional stability.

5. Closing remarks

The control of dyeing and finishing process is the key to ensure the quality of three-color lace elastic fabric, so it is necessary to make full use of the material and material characteristics of the fabric.

(1) Remove oil first and then preorder shape to avoid fabric oil agent defects on finished products.

(2) Pre-set temperature of 190℃ and finished product setting temperature of 150℃ to improve wrinkling, feel and dimensional stability of fabric.

(3) Choose Procion HE type reactive dye to dye rayon with less color on nylon.

(4) Acid dyes and cationic dyes were used to dye polyamide filament and modified polyester in one bath. Polyamide was dyed first and then modified polyester. Retarding agent M and anti-precipitation agent S were added to improve the evenness and dyeing amount.

(5) Add absorbent softener when dyeing solution and finished product are set to increase the absorbent and perspirant function of fabric.