Preparation method of chinlon 6 novel light warm-keeping stretch yarn

Abstract

The invention provides a preparation method of chinlon 6 novel light warm-keeping stretch yarn, which comprises the following preparation steps: S1, adding a cross-linking agent containing a dynamic disulfide bond and a photoresponse azobenzene group into a caprolactam monomer derived from transgenic castor oil, and carrying out polymerization reaction under the protection of nitrogen, the low-density self-repairing nylon 6 melt is obtained by optimizing the using amount of a cross-linking agent and balancing the self-repairing capacity and mechanical strength of a material through differential scanning calorimetry and dynamic mechanical analysis testing, the five-layer bionic spinning structure is adopted, the weight of the five-layer bionic spinning structure is derived from the hollow design of lotus root nodes, static air is effectively latched, and the low-density self-repairing nylon 6 melt is obtained. The heat retention property is jointly enhanced by the gradient air cavity cooperating with the core-shell aerogel and the phase change microcapsules, the lasting high elasticity is benefited from the spring core structure combined with the damp-heat setting process, the spring core structure particularly shows excellent and stable rebound capacity in a humid environment, and the comprehensive performance is far better than that of a traditional single-layer structure.

Description

Technical Field

[0001] The invention relates to the technical field of nylon 6 stretch yarn, and in particular to a preparation method of a novel lightweight and warm-keeping nylon 6 stretch yarn. Background Art

[0002] Nylon 6 new stretch yarn is a high-performance polyamide fiber made from caprolactam, endowed with excellent elasticity and resilience through advanced spinning processes. Its characteristics include high strength, excellent abrasion resistance, a soft feel, and excellent moisture-wicking properties, making it suitable for applications requiring high elasticity, such as sportswear and underwear. Through molecular structure optimization and specialized processing techniques (such as false twist texturing), it achieves low relaxation shrinkage and durable deformation recovery. It can also be blended with cotton, spandex, and other fibers to enhance overall performance. Environmentally friendly products also utilize renewable raw materials or biodegradable technologies, aligning with sustainable development trends.

[0003] Due to the limitations of the single-layer melt-spinning structure, existing nylon 6 stretch yarn needs to rely on chemical foaming agents or low-density fillers for lightweighting. However, foaming causes a significant decrease in the mechanical strength of the fiber, and the uneven distribution of the bubbles weakens the warmth retention. Although the addition of elastomers such as TPU / TPEE improves resilience, the high proportion of blending increases the density, and the elastomer molecular chains are easily hydrolyzed and broken in a hot and humid environment, resulting in a sharp drop in wet rebound rate. Secondly, although the addition of phase change materials or metal coatings in post-finishing can improve the temperature regulation / conductivity function, the interfacial bonding strength is poor, and it will fall off and fail after repeated stretching. At the same time, it will block the fiber pores and affect moisture permeability. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the shortcomings of the existing technology, the present invention provides a preparation method of a novel lightweight and warm nylon 6 stretch yarn, which solves the problem that the existing nylon 6 stretch yarn cannot achieve the advantages of lightness, warmth and elasticity at the same time.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention provides a method for preparing a novel lightweight and warm stretch yarn of nylon 6 through the following technical solutions, comprising the following preparation steps:

[0008] S1. Using caprolactam monomers derived from genetically modified castor oil, adding a crosslinker containing a dynamic disulfide bond and a photoresponsive azobenzene group, the polymerization reaction was carried out under nitrogen protection. Differential scanning calorimetry and dynamic mechanical analysis were used to optimize the crosslinker dosage and balance the self-healing ability and mechanical strength of the material to obtain a low-density self-healing nylon 6 melt;

[0009] S2. Synchronous co-extrusion using a five-channel microfluidic spinneret:

[0010] Core layer: high-temperature molten TPEE elastomer is injected, and the internal design of the spinneret optimizes the spiral flow channel to make the elastomer form a pre-strain spring structure, ensuring that the interfaces of each layer are tightly bonded;

[0011] Air cavity layer: Wrapped in bio-based nylon 6 melt, nitrogen is injected using a pulse technology coupled with specific pressure and frequency to form a gradient air cavity structure that mimics a lotus root node;

[0012] Functional layer: Core-shell aerogel microspheres and composite phase-change microcapsules are uniformly mixed into the nylon 6 melt to give the fiber active temperature regulation function;

[0013] Skin layer: Graphene / carbon nanotube mixture is blended and quenched at a specific temperature to form an initial micro-groove structure on the fiber surface;

[0014] S3. In a low-pressure vacuum environment, the fiber surface is first activated with oxygen plasma, and then bombarded with SF6 / O2 mixed gas plasma at a specific power and time to deepen and regularize the existing microgrooves in the surface layer;

[0015] S4. The etched fiber is passed through a magnetic field of specific intensity. Under the influence of the magnetic field, a dispersion of carbon nanotubes modified with magnetic nanoparticles is simultaneously sprayed onto the fiber surface. The magnetic field guides the magnetically modified carbon nanotubes to be precisely and directionally embedded and fixed in the microgrooves of the epidermis, forming a highly ordered, axially arranged conductive network, which greatly improves the stability and durability of the conductive network.

[0016] S5. Treat the fiber under specific temperature and humidity conditions, using water molecules to promote the flexible rearrangement and relaxation of the nylon molecular chain. Relaxation and retraction are carried out in a dry heat environment at a specific temperature, permanently locking the pre-strained spring structure of the core layer TPEE.

[0017] S6. The shaped fibers are subjected to multiple stretching-relaxation cycle tests in a humidity environment to verify the long-term stability of their wet elastic recovery properties, ultimately obtaining highly elastic fibers with a permanent three-dimensional curled structure.

[0018] Preferably, the core-shell structure aerogel microspheres in S2 are composed of a silica aerogel core and a polydopamine shell.

[0019] Preferably, the composite phase-change microcapsules in S2 are composed of silicon dioxide.

[0020] Preferably, the TPEE melt of the core layer in S2 is maintained at a high temperature of 240° C. to ensure fluidity, and the bio-based nylon 6 melt of the air cavity layer and the functional layer is controlled at 220-230° C. to avoid thermal degradation.

[0021] Preferably, the volume ratio of SF6 to O2 in the S3 is controlled in the range of 1.5:1-2.5:1.

[0022] Preferably, the dispersion liquid spraying in S4 adopts 0.05-0.1MPa, atomization pressure and 0.5-1.5mL / min flow rate, low-pressure fine atomization to avoid droplet agglomeration, and low flow rate to ensure that the nanotubes are fully and directionally embedded in the grooves within the magnetic field action time.

[0023] Preferably, the wet heat treatment time in S5 is set to 8-15 minutes.

[0024] (3) Beneficial effects

[0025] The present invention provides a method for preparing a novel lightweight and warm-keeping nylon 6 stretch yarn. The method has the following beneficial effects:

[0026] 1. The present invention adopts a five-layer bionic spinning structure. Its lightness is due to the hollow design imitating lotus root nodes that effectively locks static air. The warmth retention is enhanced by the gradient air cavity in conjunction with the core-shell aerogel and phase change microcapsules. The long-lasting high elasticity is due to the spring core structure combined with the wet heat setting process. Especially in humid environments, it exhibits excellent and stable rebound ability, and its comprehensive performance far exceeds that of traditional single-layer structures.

[0027] 2. The present invention combines plasma-etched moisture-conducting grooves with magnetic field-directed assembly of conductive networks to construct a highly ordered and stable multifunctional interface on the fiber surface. At the same time, through microfluidic precision spinning, lightweight, active temperature regulation and sensing / conductive functions are integrated in one go, combined with a bio-based self-healing matrix, to achieve a full-chain functional design from the fiber source to the surface. DETAILED DESCRIPTION

[0028] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] Example:

[0030] The embodiment of the present invention provides a method for preparing a novel lightweight and warm-keeping stretch yarn of nylon 6, comprising the following preparation steps:

[0031] S1. Using caprolactam monomers derived from genetically modified castor oil, adding a crosslinker containing a dynamic disulfide bond and a photoresponsive azobenzene group, the polymerization reaction was carried out under nitrogen protection. Differential scanning calorimetry and dynamic mechanical analysis were used to optimize the crosslinker dosage and balance the self-healing ability and mechanical strength of the material to obtain a low-density self-healing nylon 6 melt;

[0032] S2. Synchronous co-extrusion using a five-channel microfluidic spinneret:

[0033] Core layer: inject high-temperature molten TPEE elastomer, optimize the internal spiral flow channel of the spinneret to make the elastomer form a pre-strained spring structure, ensuring that the interfaces of each layer are tightly combined;

[0034] Air cavity layer: wrap the bio-based nylon 6 melt and inject nitrogen gas using a specific pressure and frequency coupled pulse technology to form an imitation lotus node gradient air cavity structure;

[0035] Functional layer: uniformly mix core-shell structure aerogel microspheres and composite phase change microcapsules in the nylon 6 melt to give the fiber active temperature regulation function;

[0036] Skin layer: blend graphene / carbon nanotube mixture and form initial micro-groove structure on the fiber surface through specific temperature quenching process;

[0037] S3, in a low-pressure vacuum environment, first activate the fiber surface with oxygen plasma, then use SF6 / O2 mixed gas plasma to perform specific power and time bombardment etching to deepen and regularize the existing micro-groove on the skin layer;

[0038] S4, pass the etched fiber through a specific strength magnetic field area, under the action of the magnetic field, simultaneously spray a dispersion liquid of carbon nanotubes modified by magnetic nanoparticles onto the surface of the fiber, the magnetic field force guides the magnetic modified carbon nanotubes to accurately and directionally embed and fix in the micro-groove of the skin layer, forming a highly ordered, axially arranged conductive network, greatly improving the stability and durability of the conductive network;

[0039] S5, treat the fiber under specific temperature and humidity conditions, use water molecules to promote the flexible rearrangement and relaxation of nylon molecular chains, and perform relaxation and shrinkage in a dry heat environment at a specific temperature to permanently lock the pre-strained spring structure of the core layer TPEE;

[0040] S6, perform multiple stretch-relaxation cycle tests on the set fiber under humidity environment to verify the long-term stability of its wet state elastic recovery performance, and finally obtain a high-elasticity fiber with a permanent three-dimensional crimp structure.

[0041] The core-shell structure aerogel microspheres in S2 are composed of a silica aerogel core and a polydopamine shell.

[0042] The composite phase change microcapsules in S2 are composed of silicon dioxide.

[0043] The core layer TPEE melt in S2 maintains a high temperature of 240°C to ensure fluidity, and the bio-based nylon 6 melt of the air cavity layer and the functional layer is controlled at 220-230°C to avoid thermal degradation.

[0044] In S3, the volume ratio of SF6 to O2 is controlled in the range of 1.5:1-2.5:1.

[0045] The dispersion liquid in S4 is sprayed at 0.05-0.1 MPa, atomization pressure and 0.5-1.5 mL / min flow rate, low pressure fine atomization avoids liquid droplet agglomeration, and low flow rate guarantees that the nanotubes are fully oriented and embedded into the grooves within the magnetic field action time.

[0046] The wet heat treatment time in S5 is set to 8-15 min.

[0047] Comparative example:

[0048] The existing spandex 6 is prepared by melt spinning of a single layer of elastomer.

[0049] Experimental example:

[0050] The spandex 6 prepared in the comparative example is compared with the spandex 6 prepared in the present application in terms of lightness, warmth retention and elasticity.

[0051] (1) Lightness

[0052] Test method: ASTM D792 standard for measuring fiber density

[0053] Instrument: precision density gradient column

[0054] (2) Warmth retention

[0055] Test method: ISO 11092 thermal resistance test

[0056] Conditions: 35℃ hot plate, simulating human skin temperature; record the constant temperature energy consumption difference

[0057] (3) Elasticity

[0058] Dry state elasticity: ISO 2062 standard cyclic tensile test (50 times, 20% strain)

[0059] Wet state elasticity: cyclic tensile test under the same conditions at 65% RH humidity

[0060] Index: elastic recovery rate (%) = (L0-L r ) / L0x100% (L0: original length, L r : length after recovery); the specific test results are shown in the following table:

[0061] Sample type Density (g / cm3) Example ≤1.02 Comparative Example 1.14-1.18

[0062] Table 1: Lightness comparison table

[0063] Sample type Thermal resistance R value (m2·K / W) Example 0.035-0.040 Comparative Example 0.020-0.025

[0064] Table 2: Warmth retention comparison table

[0065] Test conditions Example Comparative Example Dry state (50 cycles) 95-97％ 85-88％ Wet state (65% RH) 92-94％ 70-75％

[0066] Table 3: Comparison of elastic recovery rates

[0067] In summary, the fiber of the present invention, with its five-layer bionic structure and synergistic process, has demonstrated disruptive advantages in comparative experiments: density is reduced by more than 12%, thermal resistance is increased by 40-60%, and wet elastic recovery rate is more than 25 percentage points ahead of traditional products, completely breaking through the technical bottleneck of traditional single-layer blended nylon stretch yarn that cannot achieve "lightness, warmth and elasticity" at the same time.

[0068] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a new type of lightweight and warm nylon 6 stretch yarn, characterized in that: The method comprises the following preparation steps: S1. Using caprolactam monomers derived from genetically modified castor oil, adding a crosslinker containing a dynamic disulfide bond and a photoresponsive azobenzene group, the polymerization reaction was carried out under nitrogen protection. Differential scanning calorimetry and dynamic mechanical analysis were used to optimize the crosslinker dosage and balance the self-healing ability and mechanical strength of the material to obtain a low-density self-healing nylon 6 melt; S2. Synchronous co-extrusion using a five-channel microfluidic spinneret: Core layer: high-temperature molten TPEE elastomer is injected, and the internal design of the spinneret optimizes the spiral flow channel, so that the elastomer forms a pre-strain spring structure, ensuring that the interfaces of each layer are tightly bonded; Air cavity layer: Wrapped in bio-based nylon 6 melt, nitrogen is injected using a pulse technology coupled with specific pressure and frequency to form a gradient air cavity structure that mimics a lotus root node; Functional layer: Core-shell aerogel microspheres and composite phase-change microcapsules are uniformly mixed into the nylon 6 melt to give the fiber active temperature regulation function; Skin layer: Graphene / carbon nanotube mixture is blended and quenched at a specific temperature to form an initial micro-groove structure on the fiber surface; S3. In a low-pressure vacuum environment, the fiber surface is first activated with oxygen plasma, and then bombarded with SF6 / O2 mixed gas plasma at a specific power and time to deepen and regularize the existing microgrooves in the surface layer; S4. The etched fiber is passed through a magnetic field of specific intensity. Under the influence of the magnetic field, a dispersion of carbon nanotubes modified with magnetic nanoparticles is simultaneously sprayed onto the fiber surface. The magnetic field guides the magnetically modified carbon nanotubes to be precisely and directionally embedded and fixed in the microgrooves of the epidermis, forming a highly ordered, axially arranged conductive network, which greatly improves the stability and durability of the conductive network. S5. Treat the fiber under specific temperature and humidity conditions, using water molecules to promote the flexible rearrangement and relaxation of the nylon molecular chain. Relaxation and retraction are carried out in a dry heat environment at a specific temperature, permanently locking the pre-strained spring structure of the core layer TPEE. S6. The shaped fibers are subjected to multiple stretching-relaxation cycle tests in a humidity environment to verify the long-term stability of their wet elastic recovery properties, ultimately obtaining highly elastic fibers with a permanent three-dimensional curled structure.

2. The method for preparing a novel lightweight and warm nylon 6 stretch yarn according to claim 1, characterized in that: The core-shell structure aerogel microspheres in S2 are composed of a silica aerogel core and a polydopamine shell.

3. The method for preparing a novel lightweight and warm-keeping nylon 6 stretch yarn according to claim 1, characterized in that: The composite phase-change microcapsules in S2 are composed of silicon dioxide.

4. The method for preparing a novel lightweight and warm nylon 6 stretch yarn according to claim 1, characterized in that: The TPEE melt of the S2 core layer is maintained at a high temperature of 240° C. to ensure fluidity, and the bio-based nylon 6 melt of the air cavity layer and the functional layer is controlled at 220-230° C. to avoid thermal degradation.

5. The method for preparing a novel lightweight and warm nylon 6 stretch yarn according to claim 1, characterized in that: The volume ratio of SF6 to O2 in the S3 is controlled in the range of 1.5:1-2.5:

1.

6. The method for preparing a novel lightweight and warm nylon 6 stretch yarn according to claim 1, characterized in that: The dispersion in S4 is sprayed with an atomization pressure of 0.05-0.1 MPa and a flow rate of 0.5-1.5 mL / min. Low-pressure fine atomization avoids droplet agglomeration, and low flow rate ensures that the nanotubes are fully and directionally embedded in the grooves within the magnetic field action time.

7. The method for preparing a novel lightweight and warm nylon 6 stretch yarn according to claim 1, characterized in that: The wet heat treatment time in S5 is set to 8-15 minutes.