Nylon 6 color-fixing master batch, color-fixing fiber thereof and preparation method of color-fixing fiber

Abstract

The invention discloses a nylon 6 color fixing master batch, a color fixing fiber thereof and a preparation method of the color fixing fiber, and belongs to the technical field of textile fibers. In order to solve the problems of low cation dyeing fastness, complicated dyeing process and the like of the nylon fiber, a reaction product C12H10O4S.C6H6O4S.CH2O. 2Na of hydroxyl phenyl sulfonic acid monosodium salt, formaldehyde and sulfonyl bis (phenol) sodium salt is used as an acidic color fixing agent, the nylon 6 color fixing master batch and the color fixing fiber are prepared in a blending manner, the production process is simple, the cost is low, and the method is suitable for industrial production. Strong acid and high-temperature treatment is not needed in downstream dyeing; in the dyeing process, phenolic hydroxyl groups, sulfonic acid groups and other color fixing groups introduced by the acidic color fixing agent can enhance the combination of nylon 6 fibers and cationic dyes, a better color fixing effect is shown, meanwhile, due to the addition of the acidic color fixing agent, negative charges on the surfaces of the nylon 6 fibers are increased, and the acidic color fixing agent plays a role in electrostatic repulsion on dyes with negative charges, so that the color fixing effect is better. The neutral grey dye cross-dyeing prevention capability is endowed to the nylon 6 color fixing fiber.

Description

Technical Field

[0001] The present invention belongs to the technical field of textile fibers, and particularly relates to a nylon 6 color-fixing masterbatch, its color-fixing fiber and preparation method. Background Art

[0002] Nylon fibers play an important role in the textile industry due to their excellent abrasion resistance, high strength and good resilience, and are widely used in multiple fields such as clothing, home textiles, and industrial textiles. With the continuous improvement of consumers' requirements for fabric quality and appearance, the expectation for the dyeing effect of nylon fibers is also increasing day by day. An ideal dyeing effect not only requires bright and full colors, but also good color fastness and stability.

[0003] Currently, the dyeing of nylon fibers mainly uses acid dyes, neutral dyes and disperse dyes. Acid dyeing is one of the most commonly used methods for nylon fiber dyeing. Its dyeing mechanism is that the sulfonic acid group in the dye molecule forms an ionic bond with the amino group at the end or on the side chain of the nylon fiber. The advantages of acid dyes are bright color and high dye uptake rate, but their color-fixing performance is insufficient, and the washing fastness and level dyeing property are poor. The dyeing performance of neutral dyes is between that of acid dyes and cationic dyes, and is usually used for dyeing light or medium colors. Its dyeing process has relatively strict requirements for pH value, usually carried out under weakly acidic or neutral conditions. Under such conditions, the combination of the dye and the fiber is relatively mild, and the color-fixing effect is mediocre, but it is difficult to meet the requirements of high color fastness. Disperse dyes are mainly used for light-color dyeing of nylon fibers. Its dyeing process requires the use of a dispersant to evenly disperse the dye in the dye liquor to ensure that the dye can fully contact and fix on the fiber. The advantages of disperse dyes are relatively high color fastness and relatively good color-fixing effect, but the dyeing process is relatively complex and has strict requirements for the control of process parameters.

[0004] Cationic dyes are dyes that carry a positive charge in solution and have advantages such as high dye uptake rate, bright color and good color fastness. Therefore, their application in nylon fibers mainly focuses on scenarios that require high color fastness and bright color, such as high-performance sportswear, outdoor equipment, etc. However, ordinary nylon fibers have weak adsorption ability for cationic dyes, resulting in poor color-fixing effect and unsatisfactory washing fastness and light fastness. After dyeing with cationic dyes, the washing fastness of unmodified nylon fibers is usually only 3-4 levels, and chemical modification is required to improve their affinity for cationic dyes, thereby enhancing the color-fixing effect.

[0005] The Chinese patent with the application number CN110791979A and the application date of December 5, 2019 discloses a dyeing method for improving the dyeing performance of high-strength nylon 6 fabrics. By researching the dyeing process and the color fixation process, the dyeing performance of nylon 6 fabrics is improved. This method belongs to the improvement of the backend, and it is necessary to pretreat and fix the color of the fabric. A large amount of waste liquid will be generated during the process, causing a certain burden on the environment and being unfavorable to green production. The Chinese patent with the application number CN118345526A and the application date of May 6, 2024 discloses a preparation method of atmospheric-pressure easily dyeable crimped fibers. Using a blend-modified polymer as the skin and polyester as the core, after spinning and winding by the skin-core spinning process, it is successively subjected to preliminary drawing, acid solution impregnation treatment, directional hot air blowing treatment, cooling and shaping, and further drawing to obtain atmospheric-pressure easily dyeable crimped fibers. This method requires the use of a strong acid solution (pH 1 - 2.5) for impregnation and erosion treatment. The process is complex and has a relatively high risk, with high requirements for equipment and operators. At the same time, a large amount of acidic waste liquid will also be generated, posing challenges to the environment and production safety and being unfavorable to large-scale industrial production.

[0006] In summary, the existing strategies for improving the dyeing performance of nylon fibers are complex in process and not conducive to the green development of the industry. To solve problems such as low cationic dyeing fastness and cumbersome dyeing processes of nylon fibers, it is urgent to design a new type of nylon fiber with ideal color fixation effect, which can not only effectively improve the dyeing and color fixation effect of cationic dyes on nylon fibers, but also has a simple production process, and does not require strong acid and high-temperature treatment in downstream dyeing, being conducive to the ecological and environmental protection development of the industry. Summary of the Invention

[0007] To solve the problems existing in the prior art, the present invention discloses a nylon 6 color fixation masterbatch, its color fixation fiber and preparation method. The nylon 6 color fixation masterbatch and color fixation fiber are prepared by using an acidic color fixative in a blending manner, enhancing the combination of nylon 6 fibers and cationic dyes, showing a better color fixation effect, and at the same time endowing the neutral gray dye with anti-color bleeding ability.

[0008] The technical solution of the present invention is as follows:

[0009] One of the purposes of the present invention is to provide a nylon 6 color fixation masterbatch, and the nylon 6 color fixation masterbatch comprises raw materials in the following weight percentages: 5% - 15% of an acidic color fixative, and 85% - 95% of nylon 6 chips;

[0010] The acidic color fixative is the reaction product of sodium hydroxyphenyl sulfonate, formaldehyde and sodium bis(phenol)sulfonyl, and its molecular formula is C 12 H 10 O4S·C6H6O4S·CH2O·2Na.

[0011] Further, under alkaline conditions, formaldehyde acts as a cross-linking agent to undergo electrophilic substitution at the ortho-position of the phenolic hydroxyl group of sodium hydroxyphenylsulfonate, generating a hydroxymethyl intermediate. The hydroxymethyl intermediate undergoes a condensation reaction with the phenoxy group of sodium sulfonylbis(phenol) to form a compound C cross-linked by a methylene bridge. 12 H 10 O4S·C6H6O4S·

[0012] CH2O·2Na, which is the acidic fixing agent.

[0013] The second object of the present invention is to provide a method for preparing fixed-color fibers using a nylon 6 fixed-color masterbatch, comprising the following steps:

[0014] S1. Feed the acidic fixing agent from the side position of the granulator and nylon 6 chips from the main position, and after melting and blending in a twin-screw extruder, extrude and granulate to obtain a nylon 6 fixed-color masterbatch.

[0015] S2. Add the nylon 6 fixed-color masterbatch prepared in step S1 to the spinning masterbatch machine, add nylon 6 chips to the spinning hopper, melt them through a screw extruder, and then extrude and spin from the spinneret assembly to obtain nylon 6 fixed-color fibers.

[0016] Further, the mass ratio of the acidic fixing agent fed in S1 to the nylon 6 chips is 5-15%:85-95%.

[0017] Further, the heating temperature of the twin-screw granulator in S1 is set to 225°C - 235°C.

[0018] Further, the spinning melting temperature in S2 is set to 256 - 259°C.

[0019] Further, the melt after melting in S2 is extruded through the spinneret of the assembly to form a tow, and then through slow cooling, monomer suction, side blowing cooling, bundling and oiling, secondary cooling in the duct, drawing and setting, and finally winding and shaping to obtain nylon 6 fixed-color fibers.

[0020] Further, the monomer suction system consists of a suction port, a pipeline, a vacuum pump and a condenser, and draws away the heat-volatile caprolactam by generating negative pressure.

[0021] Further, the side blowing cooling temperature is controlled between 17°C and 20°C, and the wind speed is controlled between 0.45 m / s and 0.6 m / s.

[0022] Further, the bundling and oiling adopts a double-channel oiling technology and realizes step-by-step oiling through two independent oil supply systems.

[0023] The third object of the present invention is to provide a nylon 6 fixed-color fiber.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. By blending and modifying nylon 6 chips, the present invention innovatively introduces an acidic fixing agent C 12 H 10 O4S·C6H6O4S·CH2O·2Na. The fixing groups such as phenolic hydroxyl groups and sulfonic acid groups in its molecule can form hydrogen bonds with the amide groups on the nylon 6 molecular chain, significantly enhancing the binding force between the fiber and cationic dyes. Compared with the prior art that relies on strong acid pretreatment or complex post-fixing processes, the present invention adopts a one-step blending and granulation method, without high-temperature strong acid conditions, simplifies the production process, reduces wastewater discharge and energy consumption, and conforms to the trend of green manufacturing. In addition, the introduction of the acidic fixing agent increases the negative charge on the fiber surface, and effectively inhibits the cross-dyeing of neutral gray dyes through electrostatic repulsion, breaking through the dependence of traditional fixing technologies on a single dye type.

[0026] 2. The fixing fiber prepared based on the nylon 6 fixing masterbatch in the present invention shows outstanding dyeing performance. Experiments show that the fiber added with the nylon 6 fixing masterbatch has a significantly improved dye uptake rate for cationic dyes. The Lab values show that its color is deeper and the saturation is higher. It can have a higher washing fastness while reducing the amount of dyes used, effectively reducing the dye residue in the wastewater, which is beneficial to the green development of the industry. In addition, the nylon 6 fixing fiber has excellent anti-cross-dyeing ability. After being treated with different concentrations of neutral gray dyes for cross-dyeing, the fiber color has no obvious gray scale shift, which can further reduce the dye waste in the dyeing process and reduce the pressure of wastewater treatment, especially suitable for scenarios of multi-color blending or high color fastness requirements.

[0027] 3. The preparation method of the nylon 6 fixing fiber in the present invention combines the melt blending of a twin-screw extruder and the spinning process, realizing the efficient and continuous production of the nylon 6 fixing masterbatch and the fiber. First, the process parameters of this preparation method are clear and the operation is simple. There is no need for additional acid solution impregnation or complex post-treatment, significantly reducing the risk of equipment corrosion and the operation difficulty. At the same time, the addition ratio of the nylon 6 fixing masterbatch is accurately controllable, ensuring the stable performance of the fiber and being suitable for large-scale industrial production. In addition, there is no strong acid waste liquid discharge in the whole preparation process, meeting the environmental protection requirements, and promoting the transformation of the textile industry towards low-carbon and sustainable development from the source. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a dyeing presentation diagram of nylon 6 fiber after cationic dyeing treatment and cross-dyeing treatment with different concentrations of neutral gray dye solution in the performance test of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following further describes the present invention with reference to preferred embodiments. The given embodiments are only for clarifying the present invention, rather than limiting the scope of the present invention.

[0030] The materials, reagents, etc. used in the following examples can be obtained from commercial sources without special instructions;

[0031] In the quantitative tests in the following examples, three independent repeated experiments were set up, and the results were averaged;

[0032] The experimental methods in the following examples are conventional methods without special instructions;

[0033] The cationic dye solution used in the following comparative examples was prepared as follows:

[0034] According to the weight ratio of "yarn:dye = 1:0.003", 0.0090 g of cationic dye was taken (each portion of the yarn in the examples was 3.000 g), 150 mL of deionized water was measured into a beaker, and the dye was added to the beaker containing 150 mL of deionized water and stirred evenly to obtain a cationic dye solution with a concentration of 60 ppm. Seven portions of cationic dye solution with a concentration of 60 ppm were prepared for standby according to the same operation.

[0035] The neutral gray dye solution used in the following comparative examples was prepared as follows:

[0036] The same method as for preparing the cationic dye solution was used, with the difference that the weights of the neutral gray dyes were 0.0003 g, 0.0006 g, and 0.0016 g respectively, and the concentrations of the prepared neutral gray dye solutions were 2 ppm, 4 ppm, and 10 ppm respectively. Two portions of each concentration of dye solution were prepared for standby.

[0037] Example 1

[0038] This example provides a nylon 6 fixing masterbatch, and its preparation method includes the following steps:

[0039] Feed 10% acidic fixing agent C 12 H 10 O4S·C6H6O4S·CH2O·2Na from the side position of the granulator and 90% nylon 6 chips from the main position, and after entering the twin-screw extruder, melt and blend at 230 °C, and then extrude and granulate to obtain the nylon 6 fixing masterbatch.

[0040] Example 2

[0041] This example provides a nylon 6 fixing fiber, and its preparation method includes the following steps:

[0042] S1. Feed 10% acidic fixing agent C 12 H 10 O4S·C6H6O4S·CH2O·2Na from the side position of the granulator and 90% nylon 6 chips from the main position, and after entering the twin-screw extruder, melt and blend at 230 °C, and then extrude and granulate to obtain the nylon 6 fixing masterbatch;

[0043] S2. Add the nylon 6 color-fixing masterbatch into the spinning masterbatch machine and feed it at an addition ratio of 1.5%. Add nylon 6 chips into the spinning hopper, melt them through a screw extruder to obtain a melt, and the melting temperature is 258 °C;

[0044] S3. The melt is extruded through a spinneret assembly to form a tow, and then through slow cooling, monomer suction, side blowing cooling, bundling and oiling, secondary cooling in the duct, stretching and setting, and finally winding and forming to obtain nylon 6 color-fixing fibers, and the fibers are used to weave sock bands for standby.

[0045] Example 3

[0046] This example provides a method for preparing nylon 6 color-fixing fibers, including the following steps:

[0047] S1. Feed 10% acidic color-fixing agent C 12 H 10 O4S·C6H6O4S·CH2O·2Na from the side position of the granulator and 90% nylon 6 chips from the main position. After entering the twin-screw extruder, melt and blend them at 225 °C, and extrude and granulate to obtain the nylon 6 color-fixing masterbatch;

[0048] S2. Add the nylon 6 color-fixing masterbatch into the spinning masterbatch machine and feed it at an addition ratio of 1.5%. Add nylon 6 chips into the spinning hopper, melt them through a screw extruder to obtain a melt, and the melting temperature is 256 °C;

[0049] S3. The melt is extruded through a spinneret assembly to form a tow, and then through slow cooling, monomer suction, side blowing cooling, bundling and oiling, secondary cooling in the duct, stretching and setting, and finally winding and forming to obtain nylon 6 color-fixing fibers, and the fibers are used to weave sock bands for standby.

[0050] The above preparation method can also adjust the mass ratio of the fed acidic color-fixing agent to nylon 6 chips to 5%:95% or 15%:85% according to the actual operation conditions; set the heating temperature of the twin-screw extruder to 235 °C and the spinning melting temperature to 259 °C.

[0051] Comparative Example 1

[0052] This comparative example provides a method for preparing nylon 6 fibers, including the following steps:

[0053] Put 100% of nylon 6 chips into the spinning hopper, and prepare nylon 6 fibers through the same spinning process as above, and use the fibers to weave sock bands for standby.

[0054] Performance Test

[0055] [[ID=4l]]1. Test of dyeing ability and anti-cross-dyeing ability of neutral gray dye

[0056] S1. Take 3 g of each of the nylon 6 fixed color fiber prepared in Example 2 and the nylon 6 fiber prepared in Comparative Example 1, immerse them in a cationic dye solution with a concentration of 60 ppm, and soak and stir them at 80° C. for 30 min to uniformly color them, to obtain dyed cationic nylon 6 fiber and cationic nylon 6 fixed color fiber, and then wash them twice with water and dry them naturally;

[0057] S2. Immerse the cationic nylon 6 fiber and cationic nylon 6 fixed color fiber dyed in S1 in neutral gray dye solution with concentrations of 2ppm, 4ppm, and 10ppm, respectively, soak and stir at 80°C for 30 minutes to obtain neutral gray cross-dyed nylon 6 fiber and nylon 6 fixed color fiber, then wash them twice and dry them naturally.

[0058] S3. Under natural light, measure the fiber dyeing Lab values after cationic dyeing and cross-dyeing with different concentrations of neutral gray dye to determine the specific dyeing conditions.

[0059] Table 1 Dyeing Lab values of nylon 6 fixed color fiber and nylon 6 fiber

[0060]

[0061] The test results are shown in Table 1 and Figure 1 As shown in the figure, under the same cationic dyeing conditions, nylon 6 fixed color fiber shows a deeper and more saturated color than nylon 6 fiber, indicating that the introduction of acidic fixing agent significantly improves the dyeing effect of nylon 6 fiber in cationic dye solution, which can reduce the amount of dye used and thus reduce the dye residue in the wastewater, which is conducive to the green development of the industry.

[0062] from Figure 1 The dyeing results show that after cross-dyeing treatment with different concentrations of neutral gray dye solution, the nylon 6 fixed color fiber has no obvious cross-dyeing. In contrast, the color of the nylon 6 fiber garters is obviously gray. As the concentration of the neutral gray dye solution increases, the color of the nylon 6 fiber gradually darkens. This shows that the nylon 6 fixed color fiber of the present invention has the ability to prevent cross-dyeing with neutral gray dye after being dyed with cationic dyes.

[0063] In summary, the addition of an acidic fixing agent to nylon 6 chips in the present invention significantly improves the dyeing effect of nylon 6 fibers, reduces the amount of dye used, and imparts to nylon 6 fibers the ability to prevent cross-dyeing of neutral gray dyes.

[0064] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A nylon 6 color fixing masterbatch, characterized in that, The nylon 6 color fixing masterbatch comprises raw materials in the following weight percentages: 5%-15% of an acidic color fixing agent and 85%-95% of nylon 6 chips; The acid fixing agent is the reaction product of sodium hydroxyphenyl sulfonate, formaldehyde and sodium sulfonyl bis(phenol), and its molecular formula is C 12 H 10 O4S·C6H6O4S·CH2O·2Na.

2. The nylon 6 color fixing masterbatch according to claim 1, characterized in that, Under alkaline conditions, formaldehyde acts as a crosslinking agent and undergoes electrophilic substitution at the ortho position of the phenolic hydroxyl group of sodium hydroxyphenylsulfonate to form a hydroxymethyl intermediate. The hydroxymethyl intermediate undergoes a condensation reaction with the phenoxy group of sodium sulfonylbis(phenol) to form compound C crosslinked by a methylene bridge. 12 H 10 O4S·C6H6O4S·CH2O·2Na, that is, the acidic fixing agent.

3. A method for preparing color-fast fibers using the nylon 6 color-fixing masterbatch as described in claim 1 or 2, characterized in that, It includes the following steps: S1. Feed the acidic color fixing agent from the side of the granulator and feed the nylon 6 chips from the main position, then enter a twin-screw extruder for melt blending and extrusion granulation to obtain the nylon 6 color fixing masterbatch; S2. Add the nylon 6 color fixing masterbatch prepared in step S1 into a spinning masterbatch machine, add nylon 6 chips into the spinning hopper, melt them through a screw extruder and extrude spinning from the spinneret pack to obtain nylon 6 color fixing fibers.

4. The preparation method of a nylon 6 color-fixing fiber according to claim 3, characterized in that, In S1, the mass ratio of the fed acidic color fixing agent to the nylon 6 chips is 5-15%:85-95%.

5. The preparation method of a nylon 6 color-fixing fiber according to claim 3, characterized in that, In S1, the heating temperature of the twin-screw granulator is set at 225°C-235°C.

6. The preparation method of a nylon 6 color-fixing fiber according to claim 3, characterized in that, In S2, the spinning melting temperature is set at 256-259°C.

7. The preparation method of a nylon 6 color-fixing fiber according to claim 3, wherein In S2, the molten melt forms a tow after spinning through the spinneret pack, and then undergoes slow cooling, monomer suction, side air blowing cooling, bundle oiling, secondary cooling in the duct, stretching and setting, and finally winding and forming to obtain nylon 6 color fixing fibers.

8. The preparation method of a nylon 6 color-fixing fiber according to claim 7, characterized in that, The monomer suction system consists of a suction port, a pipeline, a vacuum pump and a condenser, and sucks away the heat-vaporized caprolactam by generating negative pressure.

9. The preparation method of a nylon 6 color-fixing fiber according to claim 7, characterized in that, The bundle oiling adopts a two-way oiling technology and realizes step-by-step oiling through two independent oil supply systems.

10. A nylon 6 color fixing fiber prepared by the method according to any one of claims 3-9.

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