Lace is widely used in textile and garment, lace raw materials, style, design and style have also undergone tremendous changes, from elastic lace to elastic lace; Development from a single fiber to a variety of fibers; Especially in the color design, from the monotonous monochromatic color gradually inclined to the multi-style of three-color combination; The dyeing process is an important factor to determine the beauty and practicality of lace, its process is a complex and skilled project, we from the raw materials used in lace, dyeing chemicals, dyeing methods and lace dyeing examples to analyze the lace dyeing process and the precautions in production, improve the production quality and high-grade lace.

01

The raw material used in lace

1, the types of common lace

There are various kinds of lace, which has a single raw material composition, such as: pure nylon elastic lace, nylon elastic lace, pure polyester elastic lace, pure polyester elastic lace.

At the same time, there are also two kinds of smart matching of raw materials, such as: polyester combined nylon elastic lace, nylon combined rayon elastic lace, the first two are more suitable for the popular style of lace products.

For high-grade and brand lace products, the raw materials are usually composed of three or more kinds of raw materials to form a different color or texture of luxury lace; Such as polyester, nylon, rayon combination of three-color elastic lace, these lace composed of a variety of raw materials and then implant colorful silk, filigree and other special raw materials of elastic lace, can form a multi-color creative lace.

2, the main raw materials of lace production and their characteristics

Common lace on the market, its raw materials are roughly the following: nylon, polyester, natural fiber cotton, recycled fiber viscose silk, spandex, etc., are widely used in lace production.

Nylon: nylon, also known as nylon, has the advantages of high strength, good wear resistance and high elasticity, first by the United States DuPont Company began industrial production in 1939; In the early stage of China, most of the monomer was made from coal tar, and then the fiber polymer was made by polymerization or polycondensation reaction, and then the fiber was made by spinning and post-processing.

Polyamide macromolecules contain polar amide groups and non-polar methylene, so it has moderate hygroscopic properties, both ends of the macromolecule contain amino and carboxylic groups, with positive charge in the acidic medium, can be dyed with acid dyes.

The color yield of polyamide 6 is much thicker than that of polyamide 66. The stability of polyamide 6 to acid and oxidant is poor at room temperature, and it is stable to alkali and ammonia water. In addition, its light resistance is poor, long-term lighting, will cause macromolecular chain break, temperature drop, color yellowing, taking into account the production of lace yarn tensile force and strength requirements are relatively high, compared with other fibers, nylon has also become one of the important production of lace raw materials.

Polyester: British chemists made polyethylene terephthalate fiber, and put into production after 1949, called it nylon, China is called polyester, polyester thermal stability in several main synthetic fibers is the best, its chemical stability is related to its chemical structure, in the molecular chain, benzene ring and methylene are more stable. The ester group in the structure is the only group that can react chemically. Polyester hydrolyzes under the action of alkali, and the degree of hydrolysis varies with the type, concentration, temperature and time of alkali. Polyester has good acid resistance and high stability to oxidants and reducing agents.

Due to the tight molecular chain of polyester, no specific dyeing groups, small polarity, lack of hydrophilicity, low degree of expansion in water, so dyeing is more difficult, poor dyeability; This is due to the fact that there is no room for dye molecules in the zigzag long chain molecules of polyester, so dye molecules do not easily enter the fiber.

Disperse dyes are generally used for dyeing, dyeing methods include: carrier dyeing, high temperature and high pressure dyeing and hot melt dyeing. Because polyester initial modulus is high, elongation, resilience is poor, the crease generated in the wearing process is difficult to eliminate, therefore, in the business women's underwear lace mostly as a bag edge line is used, due to the poor comfort of polyester, not suitable for use in the close wearing lace, but can be used in some decorative clothing on the external lace, The lace produced with polyester as the main raw material is relatively crisp, the cost is low, and it is suitable for use in clothing worn outside and plays an embellishment role.

Cotton fiber has the characteristics of hygroscopic, breathable, soft and comfortable is the ideal lace raw material, cotton fiber after finishing, enhance its tension and strength, can be used for a variety of fancy lace organization.

Rayon: viscose fiber is the most important variety of artificial fiber, rich raw materials and excellent performance, especially in terms of absorption and permeability, there is no synthetic fiber can be comparable.

Due to oxidation in the production process, the carboxyl and aldehyde groups in cellulose are higher. Its wet temperature is only about 50% of the dry temperature, in general, its dyeing performance, similar to cotton fiber, dye cotton fiber, can be used to dye viscose fiber, and can obtain bright color, low temperature short time dyeing, the color is lighter than cotton; High temperature long-term dyeing is deeper than cotton, lace dyeing is mainly used reactive dyes and direct dyes. Viscose silk has good moisture absorption and air permeability, smooth and soft feel, but poor elastic recovery is easy to wrinkle, so viscose silk is often used for filling tissue.

02 Lace dye

Using different raw materials to produce lace, its dyeing materials and dyeing conditions are obviously different. For most printing and dyeing workers, the main dyes used in daily life are acid dyes, disperse dyes, reactive dyes, direct dyes and so on. The dyeing principle of various dyes, the precautions of each dyeing process and the applicable textile raw materials are the key and practical focus of dyeing.

1, acid dye

Acid dye is mainly used for nylon dyeing, acid dye dyeing, dye ionized into D-SO3- and Na+ in the dye solution, nylon fiber contains a certain number of amino and carboxyl groups (generally carboxyl groups more than amino), so it has amphotolytic properties, when adding acetic acid or sulfuric acid, amino combined with hydrogen ions to make the fiber with positive charge, so it can absorb the negative ions of the dye. The ammonia ion in the fiber can be bound to the ionic bond of D-SO3-.

At the same time, there are van der Waals force and hydrogen bond between the fibers. When the acidity of the dye bath is strong, the number of ammonia ions in the fiber increases, and the ionic bond plays the main role; when the acidity of the dye bath is weak, the van der Waals force and hydrogen bond play the main role. The pH value of the dye solution, dyeing temperature and time all have a certain influence on the dyeing effect. The lower the pH value, the more ammonia ions on the fiber, the more attractive it is to the dye anions. Therefore, the addition of acid has an obvious dyeing promotion effect. The adsorption rate of dye on the fiber surface and the diffusion rate into the fiber are accelerated. Therefore, it is necessary to control the appropriate starting dyeing temperature, heating rate and dyeing time according to the size of the dye's aggregation tendency, diffusion and dyeing performance, in order to achieve the purpose of dyeing evenness and penetration.

2, disperse dyes

Disperse dyes are relatively small molecular weight, simple structure, no water-soluble groups, is a strong hydrophobic non-ionic dyes, dyeing depends on the action of dispersant in the form of tiny particles evenly dispersed in the dye solution.

Disperse dye dyeing is characterized by bright color, good color fastness to washing and wide use. Because disperse dyes are difficult to dissolve in water, most dyes are dispersed in water with small crystal particles by means of dispersant. Only dissolved dye molecules can enter the polyester gap and diffuse inside the fiber, and the solubility of disperse dyes increases with the increase of temperature. More obvious when more than 100℃, disperse dyes dyeing lace containing polyester is generally dyed at high temperature and high pressure. Dissolved dye molecules arrive at the fiber surface during dyeing, are adsorbed by the fiber surface, and spread to the interior of the fiber at high temperature. With the adsorption of single dye molecules in the dye solution and the continuous dissolution of dye particles in the dye solution, the dye dispersed into the micelle is constantly released. After continuous supply of single molecule dye, re-adsorption, diffusion, dyeing, with the decrease of temperature, the fiber molecular chain segment stops moving, the free volume shrinks, and the dye and fiber molecules are fixed on the fiber by van der Waals force, hydrogen bond, and mechanical action.

At the same time, disperse dyes can also dye polyamide, but the wet processing fastness is poor. Disperse dyes are the most suitable dyes for dyeing spandex, especially polyester spandex, which can establish a strong intermolecular force with disperse dye molecules, and can form a small number of H bonds. Although the microstructure of the soft and hard chain segments of spandex makes disperse dyes easy to dye, it is also easy to desorption, and disperse dyes are easy to enter the interior of the fiber, but it is difficult to establish a strong combination with the soft chain segment molecules of spandex.

3, reactive dyes

Reactive dyes are a class of water-soluble dyes with reactive groups on the chemical structure, the reactive group is commonly known as the active group, in the dyeing process, the reactive group on the dye structure can react with the hydroxyl group on the cellulose fiber, the amino group on the nylon fiber, etc., to form a covalent bond, so that the dye becomes a part of the fiber macromolecules.

03 Dyeing method

Reasonable dyeing method is the necessary guarantee for the smooth progress of lace dyeing process, is the key to enterprise efficiency and product quality, different raw materials and different categories of lace, its dyeing agent composition and proportion must be strictly grasped.

1, a single raw material lace dyeing

1.1 Pure nylon without elastic lace dyeing

Acid dye X %

Levelling agent 0.5 ~ 1g/L

(NH4)2SO4 or HAC 0.5 ~ 1.5g/L, 100℃×30 '

Dark color is solid color treatment:

Color fixing agent 2 ~ 3g/L, 70℃×20 '.

1.2 Pure nylon elastic lace dyeing

Acid dye X%

Levelling agent 0.5 ~ 1g/L,

Medium dark color plus disperse dye 0.02% ~ 0.1%

(NH4)2SO4 or HAC 0.5 ~ 1.5g/L, 100℃×30min,

Dark color is solid color treatment:

Color fixing agent 2 ~ 3g/L, 70℃×20min.

1.3 Pure polyester elastic lace dyeing

Disperse dye X%

Levelling agent 0.5 ~ 1g/L

Diffusion agent NNO 2 ~ 5g/L, 130℃×60min

1.4 Pure polyester elastic lace dyeing

Disperse dye X%

Levelling agent 0.5 ~ 1g/L

120℃ ~ 130℃×60min,

If the fastness requirement is high, use reducing agent to reduce and clean 100℃×20min

2. Lace dyeing with double raw materials

2.1 Polyamide + Rayon lace

Reactive dyes X%,

Soda ash mg/L

Sodium powder mg/L 80℃×60min,

Fixing agent color fixing treatment, fixing agent 2 ~ 3g/L, soap washing treatment, soap agent 0.5 ~ 2g/L; After dyeing the rayon, with pure nylon elastic lace dyeing and then dyeing nylon

2.2 Polyester + nylon elastic lace

With the polyester elastic lace dyeing method, as far as possible to remove the disperse dye on the nylon, after dyeing the polyester fiber, the nylon elastic lace dyeing method to dye the nylon elastic lace.

3. Lace dyeing with three raw materials

There are two conventional dyeing methods for the lace of three raw materials: the first is poor fastness, disperse dyes, direct dyes, acid dyes plus powder, high temperature levelling agent 130℃ dyeing, after adding ammonium sulfide and acetic acid;

The other dyeing method is more common, better fastness, but the process time is long, first add disperse dye to dye polyester, high temperature leveling dye 130℃ dyeing, then add reactive dye to dye rayon, dyeing process add soda ash, sodium powder to promote dyeing, 80℃ dyeing, and finally add acid dye to dye polyamide, dyeing polyamide need to add leveling agent, ice acetic acid and ammonium sulfate.

Such as polyester + nylon + rayon elastic lace: with polyester elastic lace dyeing method dyeing polyester first, with nylon + rayon lace dyeing method dyeing cotton and then dyeing nylon.

In addition, if there are special materials in the lace such as: colorful silk, filigree, etc., the performance of these special materials should be considered in the dyeing process, the colorful silk can not be polluted, the filigree can not fade, should pay proper attention to the pH value of the dyeing, etc., the dyeing temperature should be slightly adjusted in the process.

04 Lace dyeing example analysis

Taking the actual lace production as an example to elaborate lace in the whole dyeing process and the matters that should be paid attention to in the actual production, in the study, the selection of three raw materials (polyester + nylon + rayon) lace as an example, this lace design is orange red polyester, purple rayon, gray blue nylon.

When dyeing, first dyeing with disperse dye, disperse dye X%, add high temperature levelling agent 0.5g/L, 130℃×30min, cut the sample after cooling, if the color is not OK, by adding dye according to the same method of operation, until the polyester color meets the customer's requirements, after all the above operations are completed, water washing, reduction cleaning;

Since then, continue to dye the cotton fiber, reactive dye X%, soda ash 10 ~ 35g/L, sodium powder 20 ~ 80g/L(Note: soda ash, sodium powder according to the actual amount of different dyes and select the corresponding concentration), in order to prevent nylon staining, generally add soda ash first, and then add sodium powder running 20min and then add reactive dye dyeing. 80℃×60 min(Note: the holding time varies with the amount of dye), if the color is not OK, follow the above method of operation, until the color meets the customer's requirements, after the completion of the above operation, first wash and then soap: soap agent 0.5 ~ 2g/L, 100℃×10min(color depth choose the corresponding concentration and holding time) should be washed after washing;

Finally dyeing polyamide: acid dye X %, acid levelling agent 0.5g/L, ammonium sulfate 1g/L, 100℃×30min, you can cut the sample for color, if the color is not OK, then operate according to the above method, after all the above operations are completed, if the color of polyamide is light, then wash clean cloth, if the color of polyamide is dark, you must do post-treatment: Color fixing agent 3g/L, 75℃×30min, washed clean.

The main points to pay attention to in the whole dyeing process of the lace are the following:

1. Different dyes should be prepared according to their reasonable applicable methods, chemical materials, to prevent abnormal appearance of color spots, color traces, and try to prevent dye hydrolysis.

2. In the whole different dyeing stages to prevent the occurrence of color flower phenomenon, the rational use of dyes and auxiliaries is required, which is closely related to the development of dyeing process.

3. If other new materials are added to the lace, we should develop a reasonable process according to the performance of the new material, such as: adding metal wire, colorful wire should consider its acid and alkali resistance, high temperature resistance and develop a reasonable process.

05 afterword

Lace, as the main decorative fabric in the modern clothing industry, is rich and varied in its organizational structure, clear pattern, level, outstanding effect, and more attractive appearance. The control of dyeing process is the key to the quality of lace, in the actual production, the material of lace should be classified, comprehensive consideration, the use of basic principles to develop a reasonable dyeing process, with strong technical guidance for enterprises to improve quality.