CN114411283B

CN114411283B - Reactive dye easy-dyeing spandex, preparation method and dyeing method thereof

Info

Publication number: CN114411283B
Application number: CN202210111048.4A
Authority: CN
Inventors: 马立伟; 周莉; 张豪
Original assignee: ZHENGZHOU ZHONGYUAN SPANDEX ENGINEERING TECHNOLOGY CO LTD
Current assignee: ZHENGZHOU ZHONGYUAN SPANDEX ENGINEERING TECHNOLOGY CO LTD
Priority date: 2022-01-26
Filing date: 2022-01-26
Publication date: 2024-01-30
Anticipated expiration: 2042-01-26
Also published as: CN114411283A

Abstract

According to the invention, the branched chain with the electrophilic group is introduced into the main chain of the polyurethane polymer, and the group has strong electron-withdrawing property in the subsequent dyeing process, can form a covalent bond with the reactive dye with the nucleophilic group, and fixes the reactive dye on the polyurethane fiber, so that the dyeing rate and the fixation rate of the polyurethane fiber on the reactive dye are improved. The polyurethane is made into a skin-core structure, and the polyurethane of the core layer can be utilized to ensure the fiber performance of the polyurethane. By adopting the dyeing method provided by the invention, the spandex fiber provided by the invention can obtain better dyeing effect by using the reactive dye with nucleophilic groups. The spandex, the core-spun yarn or the fabric prepared by the fiber can be dyed with the reactive dye at one time, the operation is simple and convenient, the dyeing is uniform, and the phenomenon of inconsistent dyeing of the spandex-containing fabric or the fabric is avoided.

Description

Reactive dye easy-dyeing spandex, preparation method and dyeing method thereof

Technical Field

The invention relates to reactive dye easy-dyeing spandex, a preparation method thereof and a dyeing method of spandex fabric by using the reactive dye.

Background

The pure cotton fabric has the advantages of softness, good moisture absorption and air permeability and the like, and is a common clothing fabric in life. However, pure cotton fabrics generally have no elasticity, and some garments such as stretch jeans and the like, which have a requirement for fabric elasticity, need to mix cotton yarns with spandex yarns to provide elasticity. Pure cotton fabrics are typically dyed using reactive dyes. The reactive dye has the characteristics of bright color, good uniformity, simple and convenient dyeing method, high color fastness, complete color spectrum, lower cost and the like, and is mainly applied to dyeing and printing of fibers such as cotton, hemp, viscose, silk, wool and the like and blended fabrics thereof. Spandex fibers are less polar due to their loose structure and are usually dyed with disperse or acid dyes. Polyether and ester groups in the molecular structure of spandex are the main part of dyeing of disperse dyes, and amide groups in the spandex crystallization area can also have hydrogen bonding effect with the dyes. The spandex molecular structure has no molecular group which can be combined with the reactive dye, so that the reactive dye is limited in the dyeing application field of spandex fabrics.

Regarding the preparation method of reactive dye easy-dyeing spandex, few prior patents report that the dyeing effect is improved basically by adding the dyeable component additive. For example, in the chinese patent document CN105442083a, a modification auxiliary agent is added into a polyurethaneurea solution, and the spandex fiber is subjected to quaternization modification to improve the dye-uptake, but only the water-soluble group of the reactive dye is subjected to ionic bond bonding, so that the dyeing effect is improved only to a limited extent; the Chinese patent document CN108138388A adopts the method that alkaline earth metal salt additive is added into stock solution, covalent bonds can be formed between the alkaline earth metal salt additive and reactive dye to improve the dye uptake, and the molecular structure of spandex is not changed. The methods provided by the patent documents have limited improvement degree of dye uptake, no firmer covalent bond is formed between the active group of the reactive dye and fiber molecules, and the dye is easy to fall off after washing or friction.

Therefore, on the basis of the existing spandex, the reactive dye-dyed spandex fiber and the preparation technology thereof are developed, and compared with the prior technical means, the invention improves the covalent bond bonding capability of the molecular groups of the spandex fiber and the reactive dye, so that the dye-uptake and the fixation rate of the reactive dye are greatly enhanced.

Disclosure of Invention

The invention aims to provide reactive dye-easy spandex, and another aim of the invention is to provide a preparation method of reactive dye-easy spandex, and a further aim of the invention is to provide a dyeing method of spandex by using reactive dye.

Among the commonly used reactive dyes, there are reactive dye molecules in which nucleophilic groups exist, which include amino groups and hydroxyl groups on aromatic rings which are originally weak in nucleophilicity in the dye molecules, or modified dyes in which alkylamino groups and alkyl hydroxyl groups are introduced into the dye molecules. Therefore, the inventor thinks that the electrophilic group is introduced into the polyurethane polymer, so that the nucleophilic group of the reactive dye and the electrophilic group in the polyurethane polymer form covalent bond combination in the dyeing process, and the dyeability of the polyurethane fiber to the reactive dye can be effectively improved.

Based on the principle, the scheme provided by the invention is as follows:

the reactive dye-easy-to-dye spandex is characterized in that the reactive dye-easy-to-dye spandex is of a skin-core structure, a skin layer is a reactive dye-easy-to-dye polyurethane polymer, and a core layer is a conventional polyurethane polymer, wherein the reactive dye-easy-to-dye polyurethane polymer comprises branched chains with electrophilic groups.

Further, the electrophilic group is a vinyl group.

Further, in the reactive dye-dyeable polyurethane polymer, the mole percentage of the diol compound containing the branched chain with the electrophilic group to the whole alcohol raw material is 5-30%.

The electrophilic group adopted by the invention is that a branched chain with vinyl is introduced into a polyurethane polymer molecular chain, the vinyl on the branched chain has stronger electrophilicity, and can form covalent bond with a nucleophilic group of a reactive dye with a nucleophilic group, so that reactive dye molecules are fixed on spandex fibers, and the dyeing property of the spandex to the reactive dye is improved.

Since the average molecular weight of the soft segment is reduced due to the low molecular weight of the diol compound with vinyl branches, the low average molecular weight of the diol compound and the branched structure have adverse effects on the tensile strength, modulus and other properties of the polyurethane polymer, so that the content of the diol containing vinyl groups in the skin structure is controlled. In the invention, in order to ensure the fiber performance of polyurethane polymer, and simultaneously consider the number of vinyl groups capable of forming covalent bonds with reactive dyes on branched chains, the mole percentage of the selected vinyl group-containing dihydric alcohol compound to the whole alcohol raw material is 5% -30%, preferably 5% -15%, more preferably 10%, above which the physical performance of spandex is poor, below which the number of groups capable of being covalently bonded with reactive dyes is too small, and the dyeing performance is insufficient. Wherein, the alcohol raw material refers to a raw material containing hydroxyl added in the stage of preparing spinning solution.

Further, the skin area of the cross section of the reactive dye-dyeable spandex accounts for 5-50%, preferably 10-30% of the whole cross section area.

The easy-to-dye spandex is arranged outside and is positioned on the skin layer, so that the physical properties of the spandex are ensured, the content of the skin layer cannot be too large, and the content of the skin layer cannot be too small for ensuring the dyeing effect.

Since the dyeability of the spandex fiber is the apparent property of the fiber surface, in order to make the prepared polyurethane fiber possess the best possible dyeability without reducing the physical properties of the fiber as much as possible, the inventor takes the polyurethane polymer with vinyl branched chains as the skin layer of the spandex fiber and takes the conventional polyurethane polymer as the core layer of the spandex fiber, so as to prepare the polyurethane fiber with a skin-core structure. The polyurethane fiber has the advantages that the number of vinyl branched chains in the polyurethane polymer can be increased in the polyurethane fiber skin layer, the binding capacity between the prepared polyurethane fiber skin layer and reactive dye is increased, the dyeability is improved, and meanwhile, the conventional polyurethane polymer is used in the polyurethane core layer, so that the fiber mechanical property of the prepared polyurethane fiber is ensured. Therefore, the skin-core structure can give consideration to the dyeability of the reactive dye and the mechanical property of the fiber of the spandex yarn, and can improve the dyeability of the reactive dye of the spandex and simultaneously maintain the mechanical property of the spandex yarn.

The preparation method of the reactive dye easy-dyeing spandex is characterized by comprising the following steps of:

1) Adding polyether glycol or polyester glycol, glycol compound with electrophilic group in side chain, micromolecular alcohol and diisocyanate into a polymerization kettle, reacting to obtain a polymer under the condition of strong stirring at 90 ℃, dissolving the obtained polyurethane polymer into a polar amide solvent, adding uniformly dispersed functional slurry, and uniformly mixing to obtain a cortex spinning solution with the concentration of 25-35%;

2) At least one of polyester diol, polytetrahydrofuran ether glycol, polycaprolactone diol and polypropylene glycol of a polyglycol ester series is mixed and reacted with at least one of 4,4 '-diphenylmethane diisocyanate, 1,5' -naphthalene diisocyanate, 1,4 '-cyclohexane diisocyanate and 4,4' -dicyclohexylmethane diisocyanate, wherein the molar ratio of diisocyanate to diol is 1.6-2.1, after the reaction, the mixture is dissolved in an amide polar solvent, a chain extender and a terminator are added to prepare a polyurethane urea solution, and the polyurethane urea solution is mixed with the uniformly dispersed functional slurry to finally obtain a polyurethane urea core spinning solution with the concentration of 35-45%;

3) The skin-core type composite spinning component is used for dry spinning to form the reactive dye easy-dyeing spandex with the skin-core structure taking the skin-layer spinning solution as the skin layer and the core-layer spinning solution as the core layer.

Wherein, the sequence of the step 1) and the step 2) can be exchanged or carried out simultaneously.

The concentration of the spinning solution of the skin layer prepared in the step 1) is lower than that of the spinning solution of the core layer prepared in the step 2), because if the concentration of the skin layer is higher, the solvent content of the skin layer is relatively lower and can be volatilized completely rapidly, so that a layer of solid film is formed on the skin layer, the volatilization of the solvent of the core layer is influenced, and the solvent content of the skin layer needs to be improved to ensure the normal volatilization of the solvent of the core layer, so that the concentration of the skin layer is lower than the solid content of the core layer.

Further, the diol compound having an electrophilic group in the side chain in step 1) is preferably 2-vinyl propane-1.3 diol.

Further, the polyether glycol in the step 1) is polytetrahydrofuran ether glycol, and the molecular weight of the polyether glycol is preferably 1000-2000; the polyester diol is one or two of polybutylene glycol oxalate and polycarbonate diol, and the molecular weight of the polyester diol is preferably 1000-2000.

Further, the small molecule alcohols in the step 1) comprise dihydric alcohols and monohydric alcohols, wherein the dihydric alcohols are selected from one or more of ethylene glycol, 1, 4-butanediol, diethylene glycol, tripropylene glycol and vinyl diethylene glycol; the monohydric alcohol is selected from one or more of vinyl glycol ether and 4-hydroxybutyl vinyl ether.

The dihydric alcohol compound in the micromolecular alcohol plays a role in chain extension, and the monohydric alcohol plays a role in termination, and because the amine chain extender and the terminator react with vinyl groups in the raw materials of the cortical polyurethane polymer, the molecular weight and the content of the vinyl groups of the prepared polymer solution are influenced, and therefore the vinyl-containing cortical polyurethane solution is prepared by using the alcohol for chain extension.

The vinyl glycol ether and the 4-hydroxybutyl vinyl ether are adopted as small molecular alcohols, so that the vinyl content of the skin polymer can be further improved, and the effect of further improving the dyeing effect of the product is achieved.

Preferably, the molar equivalent of the 2-vinyl propane-1.3 diol accounts for 10 to 30 percent of the molar equivalent of the total alcohol raw materials.

Further, the chain extender and terminator of the polyurethane polymer of the core layer in the step 2) are at least two of ethylenediamine, propylenediamine, 1, 6-hexamethylenediamine, methyl dipropylamine, 1, 3-diamino-4-methylcyclohexane, diethylamine, cyclohexylamine, diisopropylamine, ethanolamine, diethanolamine, N, N' -bis (2-hydroxypropyl) aniline.

Further, the functional slurry includes: one or more of an ultraviolet resistant agent, an antioxidant, a lubricant, a chlorine resistant agent and a delustring agent are ground by a grinder to achieve the purpose of uniform dispersion.

A dyeing method of reactive dye-easy-dyeing polyurethane fiber is characterized by comprising the following steps:

1) The reactive dye easy-dyeing spandex fiber prepared by the method is deoiled;

2) Preparing a dye liquor with the concentration of 1% -3% of reactive dye, wherein the reactive dye is a reactive dye with nucleophilic groups, 10-30g of sodium sulfate or sodium chloride is added into each liter of dye liquor, and the pH value of the dye liquor is regulated to enable the solution to be in the range of 4.5-11;

3) Weighing a spandex fiber sample, placing the spandex fiber sample in a dyeing cup, and adding dye liquor according to the bath ratio of 1:10-1:50;

4) And (3) dyeing, starting an infrared sample dyeing machine, heating to 40-50 ℃, putting into a dyeing cup, and preserving heat for 10-30min. Heating to 70-90 ℃, preserving heat for 20-50min, cooling to normal temperature, and taking out a sample;

5) Soaping, namely selecting soap powder or detergent, preparing soaping liquid with the concentration of 5-10g/L, soaping at the temperature of 70-90 ℃ for 10-30min, and taking out a sample.

Wherein the purpose of the soaping is to remove the surface flooding of the fibers.

Further, the deoiling treatment in the step 1) is to add a deoiling agent into hot water at 80-90 ℃, and soak the spandex fiber for 10-30min.

Since the polyurethane polymer with the easily-dyed skin layer adopts alcohol chain extension, the polyester polyurethane is obtained, and is easy to hydrolyze under the strong acid or strong alkaline condition, so that the dyeing liquid is kept to be slightly acid or alkaline in the dyeing process, and the spandex fiber is dyed under the dyeing condition that the PH is 4.5-11.

Further, the nucleophilic group of the reactive dye is one or more nucleophilic groups selected from alkylamino, alkylhydroxy, aromatic ring with hydroxy, and aromatic ring with amino.

Advantageous effects

Compared with the prior art, the technical scheme of the invention has the advantages that the electrophilic group is introduced into the main chain of the polyurethane polymer, the group has stronger electron-withdrawing property in the subsequent dyeing process, and can form a covalent bond with the active dye with the nucleophilic group, so that the active dye is fixed on polyurethane fiber, and the dyeing rate and the fixation rate of the polyurethane fiber on the active dye are improved. The polyurethane is made into a skin-core structure, and the polyurethane of the core layer can be utilized to ensure the fiber performance of the polyurethane. By adopting the dyeing method provided by the invention, the spandex fiber provided by the invention can obtain better dyeing effect by using the reactive dye with nucleophilic groups.

The spandex, the core-spun yarn or the fabric prepared by the fiber can be dyed with the reactive dye at one time, the operation is simple and convenient, the dyeing is uniform, and the phenomenon of inconsistent dyeing of the spandex-containing fabric or the fabric is avoided.

Examples

Hereinafter, exemplary embodiments of the present invention will be described in detail, which are exemplary and intended to explain the present invention and are not to be construed as limiting the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. In the interest of clarity and conciseness, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals.

In particular, the invention provides reactive dye easy-to-dye spandex, a preparation method and a dyeing method thereof. The method comprises the following steps:

the reactive dye easy-dyeing spandex is characterized in that the reactive dye easy-dyeing spandex is of a skin-core structure, a skin layer is a reactive dye easy-dyeing polyurethane polymer, and a core layer is a conventional polyurethane polymer, wherein the reactive dye easy-dyeing polyurethane polymer comprises reactive dye easy-dyeing branched chains. The reactive dye-dyeable branched chain is not particularly limited as long as the dyeable branched chain has an electrophilic group capable of reacting with a nucleophilic group in the reactive dye, and the reactive dye-dyeable branched chain may be a branched chain having an electrophilic group such as vinyl, nitrobenzene, aldehyde ketone group, carbonyl group, or methylolacrylamide. Vinyl groups can be added to spandex fibers by adding 2-vinyl propane-1.3 diol to the spandex raw material, and the method is simple in process and low in cost, so that the electrophilic group is preferably vinyl. In the reactive dye dyeable polyurethane polymer, the reactive dye dyeable branched chain-containing alcohol compound accounts for 5-30% of the total alcohol raw material by mole. The skin area of the cross section of the reactive dye dyeable spandex is limited to 5-50%, preferably 10-30% of the total cross section area.

The reactive dye easy-dyeing spandex is prepared by the following steps:

1) Adding polyether glycol or polyester glycol, a glycol compound with vinyl group in a side chain, micromolecular alcohols and diisocyanate into a polymerization kettle, reacting to obtain a polymer under the condition of strong stirring at 90 ℃, dissolving the obtained polyurethane polymer into a polar amide solvent, adding uniformly dispersed multifunctional slurry, and uniformly mixing to obtain a cortex spinning solution with the concentration of 25-35%;

according to the invention, a bulk polymerization mode is adopted to prepare the cortex spinning solution, and main raw materials such as a dihydric alcohol compound, a dihydric alcohol compound containing vinyl, small molecular alcohols, diisocyanate and the like are added at one time, and after the polymer is obtained by reaction, the polymer is dissolved in a solvent to obtain the spinning solution; because amine chain extension can react with groups of reactive dyes easy to dye branched chains to influence components of spinning stock solution, the invention adopts micromolecular alcohols as chain extension substances.

2) At least one of polyester diol, polytetrahydrofuran ether glycol, polycaprolactone diol and polypropylene glycol of the polyethylene glycol ester series is mixed and reacted with at least one of 4,4 '-diphenylmethane diisocyanate, 1,5' -naphthalene diisocyanate, 1,4 '-cyclohexane diisocyanate and 4,4' -dicyclohexylmethane diisocyanate, wherein the molar ratio of the diisocyanate to the diol is between 1.6 and 2.1, the mixture is dissolved in an amide polar solvent after the reaction, a chain extender and a terminator are added to prepare a polyurethane urea solution, the uniformly dispersed slurry containing multiple functions is mixed with the polyurethane urea solution, and finally the polyurethane urea core spinning solution with the concentration of 35 to 45 percent is obtained;

In the sheath-core type composite spinning component, the ratio of the flow rate of the sheath spinning solution to the flow rate of the core spinning solution is 0.05-1.

A dyeing method of reactive dye-easy-dyeing polyurethane fiber comprises the following steps:

1) Degreasing the easy-to-dye polyurethane fiber prepared by the method;

the presence of the fiber surface finish can cause difficult dye-up, so that the fiber surface finish is generally removed by selecting a degreasing agent before dyeing.

usually, the dye is dyed in light color, the dye concentration is about 1% -2%, and the dye is dyed in dark color, which is higher, and about 3%.

Sodium sulfate and sodium chloride are neutral electrolytes, have the effect of promoting dyeing, ensure the concentration difference of ions in the solution and promote dye ions to approach fibers. The adsorption rate of the dye and the adsorption density of the fiber surface can be improved. The ionic strength of the solution can be effectively improved by increasing the concentration of the electrolyte, and the reaction of the dye and the fiber can be accelerated. If the electrolyte concentration is too low, the fixation effect cannot be achieved, if the concentration is too high, the degree of precipitation caused by aggregation of the dye in the solution is easily increased, the fixation rate and efficiency of the dye are also reduced along with the increase of the electrolyte concentration, and the fixation reaction is not good.

The PH of the solution has an effect on the solubility of the polyester spandex. The polyester spandex is easy to dissolve under the conditions of strong acidity and strong alkalinity with small PH value, so that weak acid, weak base or neutral environment is needed.

3) Weighing a spandex fiber sample, and adding dye liquor according to the bath ratio of 1:10-1:50;

the bath ratio refers to the mass ratio of spandex fiber to dye liquor. The bath ratio is related to the utilization rate of dye, leveling property, waste water amount and the like. Too large a bath ratio is advantageous for level dyeing, but reduces the dye utilization, and the absorption of the dye by the fiber is quantitative, so that unabsorbed dye liquor is easy to waste. If the bath ratio is too small, the dye liquor quality is low, and the fiber cannot be completely dyed.

4) And (3) dyeing, starting an infrared sample dyeing machine, heating to 40-50 ℃, putting into a dyeing cup, and preserving heat for 10-30min. Heating to 70-90 ℃, preserving heat for 20-50min, cooling to normal temperature, and taking out a sample; after dyeing, the absorbance of the residual dye liquor can be measured by a spectrophotometer and the dye uptake can be calculated.

The dyeing step is divided into two sections for heat preservation, wherein the first section is a dyeing process, and the heat preservation time is the time for fully contacting the dyed fiber with the dye liquor. The second stage is the fixation process, where the temperature is raised, a process that allows the dye and fiber to react well.

5) Soaping, namely selecting soap powder or detergent, preparing soaping liquid with the concentration of 5-10g/L, soaping at the temperature of 70-90 ℃ for 10-30min, and taking out a sample. After soaping, the absorbance of the soaping liquid can be measured by a spectrophotometer and the fixation rate can be calculated.

The reason of soaping is to remove floating color on the surface of the fiber, remove unfixed dye and salt, and ensure that the PH of the fabric is close to neutral.

The present invention will be described in more detail by examples.

Example 1

Firstly, preparing reactive dye easy-dyeing spandex, which comprises the following steps:

step 1: preparation of reactive dye easy-dyeing spandex skin layer spinning dope

1) The polytetramethylene ether glycol with the number average molecular weight of 2000, 4' -diphenylmethane diisocyanate, 2-vinyl propane-1.3 diol and ethylene glycol are mixed and stirred vigorously, and react for 1h at the temperature of 90 ℃ to prepare the polymer. The NCO/OH molar ratio was 10% mol of the 1, 2-vinyl propane-1.3 diol content.

2) DMAC was added to the polymer and stirred for 30min to form a 30% strength solution.

3) 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) -benzotriazole, triethylene glycol bis beta- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, magnesium stearate and titanium dioxide are mixed and added into a DMAC solvent, and the mixture is stirred by a stirrer and ground by a grinder to achieve the aim of uniform dispersion, wherein the mass percentage concentration of the prepared slurry is 30%;

4) And adding the slurry into a polymer solution to prepare a cortex spinning solution, wherein the mass ratio of the slurry to the polymer solution is 1:18.

Step 2: preparation of reactive dye easy-dyeing spandex core layer spinning solution

1) Polytetramethylene ether glycol (number average molecular weight 2000) and 4,4' -diphenylmethane diisocyanate were reacted at 90 ℃ for 120min to prepare a prepolymer, wherein the molar ratio NCO/oh=1.7.

2) The prepared prepolymer was dissolved in N, N-dimethylacetamide to give a 40% strength solution.

3) Ethylenediamine, pentylene diamine and diethylamine were mixed in a DMAC solvent to form a 7% strength mixture, which was added to the prepolymer solution after mixing, and stirred rapidly to produce a polymer solution with an amine group/isocyanate group molar ratio = 1.03.

4) 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) -benzotriazole, triethylene glycol bis beta- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, magnesium stearate and titanium dioxide are mixed and added into a DMAC solvent, and the mixture is stirred by a stirrer and ground by a grinder to achieve the aim of uniform dispersion, wherein the mass percentage concentration of the prepared slurry is 40%;

5) And adding the slurry into a polymer solution to prepare a core layer spinning solution, wherein the mass ratio of the slurry to the polymer solution is 1:16.

Step 3: preparation of reactive dye easy-to-dye spandex

And (3) the two spinning solutions are subjected to dry spinning through a skin-core type composite spinning component to obtain the reactive dye easy-dyeing spandex. In the spinning process, the ratio of the flow rates of the spinning solution of the sheath layer to the core layer is 3:7.

Through the steps, the reactive dye-easy-to-dye spandex is prepared, the reactive dye-easy-to-dye spandex is of a skin-core structure, the skin layer is of a polyurethane polymer which is easy-to-dye by the reactive dye and contains vinyl branched chains, and the core layer is of a conventional polyurethane polymer. The skin area of the cross section of the reactive dye-susceptible spandex accounts for 36% of the whole cross section area.

Then, the reactive dye-dyeable spandex is dyed by the reactive dye, and the steps are as follows:

1) The easy-to-dye polyurethane fiber prepared by the method is subjected to deoiling treatment: adding an oil removing agent into hot water at 80 ℃, then adding a spandex fiber sample, soaking and preserving heat for 22min;

2) Preparing a dye liquor with the concentration of 2% of reactive dye, wherein the reactive dye is a reactive dye with nucleophilic groups, 25g of sodium sulfate is added into each liter of dye liquor, and the pH value of the dye liquor is regulated to 7.5;

3) Weighing 5g of spandex fiber sample, placing the spandex fiber sample in a dyeing cup, and adding dye liquor according to a bath ratio of 1:20;

4) And (3) dyeing, starting an infrared sample dyeing machine, heating to 45 ℃, putting into a dyeing cup, and preserving heat for 25min. Heating to 80 ℃, preserving heat for 35min, cooling to normal temperature, and taking out a sample;

5) Soap powder is selected for cleaning, soap solution with the concentration of 8g/L is prepared, the temperature is 80 ℃, the soap solution is used for 20min, and the sample is taken out.

Example 2

1) The polytetramethylene ether glycol with the number average molecular weight of 2000, 4' -diphenylmethane diisocyanate, 2-vinyl propane-1.3 diol and ethylene glycol are mixed and stirred vigorously, and react for 1h at the temperature of 90 ℃ to prepare the polymer. The NCO/OH molar ratio was 0.95,2-vinyl propane-1.3 diol, 15 mole% of the diol content.

2) DMAC was added to the polymer and stirred for 30min to form a 35% strength solution.

3) 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) -benzotriazole, triethylene glycol bis beta- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, magnesium stearate and titanium dioxide are mixed and added into a DMAC solvent, and the mixture is stirred by a stirrer and ground by a grinder to achieve the aim of uniform dispersion, wherein the mass percentage concentration of the prepared slurry is 35%;

2) The prepared prepolymer was dissolved in N, N-dimethylacetamide to give a 35% strength solution.

4) 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) -benzotriazole, triethylene glycol bis beta- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, magnesium stearate and titanium dioxide are mixed and added into a DMAC solvent, and the mixture is stirred by a stirrer and ground by a grinder to achieve the aim of uniform dispersion, wherein the mass percentage concentration of the prepared slurry is 35%;

Step 3: preparation of reactive dye easy-to-dye spandex

And (3) the two spinning solutions are subjected to dry spinning through a skin-core type composite spinning component to obtain the reactive dye easy-dyeing spandex.

In the spinning process, the ratio of the flow rates of the spinning solution of the skin layer to the core layer is 2:8.

Through the steps, the reactive dye-easy-to-dye spandex is prepared, the reactive dye-easy-to-dye spandex is of a skin-core structure, the skin layer is of a polyurethane polymer which is easy-to-dye by the reactive dye and contains vinyl branched chains, and the core layer is of a conventional polyurethane polymer. The skin area of the cross section of the reactive dye-susceptible spandex accounts for 25% of the whole cross section area.

1) The easy-to-dye polyurethane fiber prepared by the method is subjected to deoiling treatment: adding an oil removing agent into hot water at 85 ℃, then adding a spandex fiber sample, soaking and preserving heat for 25min;

2) Preparing a dye liquor with the concentration of 3% of reactive dye, wherein the reactive dye is a reactive dye with nucleophilic groups, 20g of sodium chloride is added into each liter of dye liquor, and the pH value of the dye liquor is regulated to 7;

3) Weighing 5g of spandex fiber sample, placing the spandex fiber sample in a dyeing cup, and adding dye liquor according to a bath ratio of 1:25;

4) And (3) dyeing, starting an infrared sample dyeing machine, heating to 48 ℃, putting into a dyeing cup, and preserving heat for 22min. Heating to 85 ℃, preserving heat for 30min, cooling to normal temperature, and taking out a sample;

5) Soap powder is selected for cleaning, soap solution with the concentration of 7.5g/L is prepared, the temperature is 82 ℃, the soap solution is used for 25min, and the sample is taken out.

The dyeing results of the two examples are shown in the following table, and comparison shows that the dyeing rate and the color fastness of the reactive dye-easy spandex provided by the invention are greatly improved compared with those of common spandex.

Examples	Dye uptake%	Fixation rate%
			Example 1	≥80	≥80
Example 2	≥80	≥80
			Common spandex	≥20	≥10

Claims

1. The reactive dye-easy-to-dye spandex is characterized in that the reactive dye-easy-to-dye spandex is of a skin-core structure, a skin layer is of reactive dye-easy-to-dye polyurethane polymer, and a core layer is of conventional polyurethane polymer, wherein the reactive dye-easy-to-dye polyurethane polymer comprises branched chains with electrophilic groups, the electrophilic groups are vinyl groups, raw materials of the reactive dye-easy-to-dye polyurethane polymer comprise alcohol compounds with vinyl branched chains, and the alcohol compounds with vinyl branched chains account for 5-30% of the mol percentage of the whole alcohol raw materials.

2. The reactive dye dyeable spandex of claim 1, wherein the reactive dye dyeable spandex has a skin area of 5-50% of the total cross-sectional area.

3. A process for the preparation of reactive dye dyeable spandex according to any one of claims 1-2, comprising the steps of:

2) At least one of polyester diol, polytetrahydrofuran ether glycol, polycaprolactone diol and polypropylene glycol of a polyglycol ester series is mixed and reacted with at least one of 4,4 '-diphenylmethane diisocyanate, 1,5' -naphthalene diisocyanate, 1,4 '-cyclohexane diisocyanate and 4,4' -dicyclohexylmethane diisocyanate, wherein the molar ratio of diisocyanate to diol is 1.6-2.1, the mixture is dissolved in an amide polar solvent after the reaction, a chain extender and a terminator are added to prepare a polyurethane urea solution, and the uniformly dispersed functional slurry is mixed with the polyurethane urea solution to finally obtain a polyurethane urea core spinning solution with the concentration of 35-45%;

4. The method for preparing reactive dye dyeable spandex according to claim 3, wherein the diol compound having an electrophilic group in the side chain in step 1) is 2-vinyl propane-1, 3 diol.

5. The method for preparing reactive dye dyeable spandex according to claim 4, wherein the molar equivalent of 2-vinyl propane-1, 3 diol is 10% -30% of the molar equivalent of all alcohol raw materials.

6. A method of dyeing reactive dye-dyeable spandex according to any one of claims 1 to 2, comprising the steps of:

1) Deoiling the reactive dye-easy-dyeing spandex fiber;

4) The method comprises the steps of dyeing, starting an infrared sample dyeing machine, heating to 40-50 ℃, putting into a dyeing cup, preserving heat for 10-30min, heating to 70-90 ℃, preserving heat for 20-50min, cooling to normal temperature, and taking out a sample;

7. The method for dyeing spandex with a reactive dye according to claim 6, wherein the nucleophilic group of the reactive dye is one or more of an alkylamino group, an alkylhydroxy group, an aromatic ring having a hydroxyl group, and an aromatic ring having an amino group.

8. Use of a reactive dye dyeable spandex according to any one of claims 1-2 for core-spun yarns, fabrics or garments.