Preparation method of enhanced warp-knitted lace fabric

Abstract

The invention discloses a preparation method of an enhanced warp-knitted lace fabric, and aims to solve the problems that fibers such as cotton fibers with relatively high water absorption capacity do not have a quick-drying characteristic, have poor antibacterial performance after long-term retention of water, still go mouldy and stink, and are low in skin-friendly property. According to the technical scheme, the method is characterized by comprising the following steps that S1, spandex filaments are stretched to a certain drafting length, then nylon filaments are evenly wound on the outer surfaces of the stretched spandex filaments according to a certain twist degree, and the nylon elastic covering yarn is obtained. The antibacterial acarus killing layer is made of cotton fibers with high water absorption, and treatment is conducted through composite alkali liquor, alkali liquor, a mercaptoacetic acid solution and a silver nitrate solution in sequence in the preparation process, so that antibacterial substances can be stably embedded into the fibers instead of being only attached to the surface layers of the fibers, and the antibacterial acarus killing effect is achieved. Furthermore, good antibacterial performance can be kept in the states of multiple times of water washing and long-term soaking.

Description

Technical Field

[0001] This invention relates to the field of warp-knitted lace fabric technology, and more specifically, to a method for preparing an enhanced warp-knitted lace fabric. Background Technology

[0002] Warp-knitted lace fabric is a knitted fabric in which weft yarns form a large weft pattern on the ground fabric. The base fabric of lace fabric is mostly a mesh fabric, which is soft but not brittle, supple and elastic, and firm but not silicone. The patterned parts are clearly distinguishable from the unpatterned parts, and the patterns are unique and elegant.

[0003] Depending on the requirements of the lace, warp-knitted lace fabrics are mainly made of 3.3-68 tex synthetic fibers and recycled fibers, but cotton yarn is also sometimes used to weave lace.

[0004] The basic weave of warp-knitted lace fabric is a hexagonal mesh structure and a rectangular mesh structure. According to the shape of the lace, there are wide lace and narrow lace, and solid-color lace and colored lace. The selvage has two types: straight stripes and curved stripes. A type of Raschel lace has a vertical height of 300 rows. To weave the pattern using dozens of combs, a large amount of labor, time, and chain blocks are required. Generally, several types of lace can be woven simultaneously on the same machine. After setting, they need to be separated again, so a special weave is used between each pair of lace threads: an open chain loop, often using thicker yarn to provide sufficient tension. Complex lace can be separated using a cutting method, the disadvantage of which is that the resulting edge is not neat; a melting method can also be used. The working width is 213.4-426.7cm (84-168 inches), the commonly used machine gauge is 12-36 gauge, and the fabric weight per unit area is 30-100g / m2. Most are processed into white. To enhance the stiffness of lace during use, sizing is often required during fabric finishing.

[0005] However, for synthetic fibers and recycled fibers, fabrics with better antibacterial properties can usually be obtained after antibacterial treatment. But for fibers such as cotton, which have strong water absorption capacity, due to their lack of quick-drying properties, their antibacterial performance is poor after moisture remains for a long time, and they will still have problems such as mold and odor, and the fabric has low skin-friendliness.

[0006] Therefore, a solution needs to be proposed to address this problem. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing an enhanced warp-knitted lace fabric. In the preparation process of the antibacterial and mite-repellent layer, the fabric is treated sequentially with a composite alkali solution, an alkali solution, a mercaptoacetic acid solution, and a silver nitrate solution, thereby maintaining good antibacterial properties even after multiple washes and prolonged immersion.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a method for preparing an enhanced warp-knitted lace fabric, comprising the following steps: Step S1: stretching spandex yarn to a certain stretch length, and then uniformly winding nylon yarn around the outer surface of the stretched spandex yarn with a certain twist to obtain nylon elastic covered yarn;

[0009] Step S2: First, the nylon elastic covered yarn is placed in a composite alkaline solution and treated at 60-75℃ for 20-40 minutes, then treated with alkaline solution at 50-65℃ for 12-18 minutes, and then washed; next, the treated nylon elastic covered yarn is placed in a mercaptoacetic acid solution and immersed at 170-185℃ for 35-45 minutes, and then washed and dried; then the nylon elastic covered yarn is activated under high temperature and high pressure, and finally placed in a silver nitrate solution and immersed at 95-110℃ for 30-50 minutes, and then washed and dried to obtain antibacterial and anti-mite cotton fiber;

[0010] Step S3: Using terephthalic acid and ethylene glycol as raw materials, terephthalic acid and ethylene glycol are pressurized and esterified to obtain polyester esterified product. Then, the polyester esterified product is subjected to atmospheric pressure esterification reaction to obtain atmospheric pressure esterified product. Then, the atmospheric pressure esterified product and antibacterial agent are subjected to polycondensation reaction to prepare antibacterial polyester masterbatch.

[0011] Step S4: The antibacterial polyester masterbatch and high-viscosity polyester chips prepared in step S3 are melt-blended and granulated using a twin-screw extruder to prepare antibacterial polyester chips, wherein the mass fraction of antibacterial polyester masterbatch in antibacterial polyester chips is 5-30%; the obtained antibacterial polyester chips are vacuum dried and pre-crystallized at 80℃ for 12h, and then crystallized at 120℃ for 12h. Then, by melt spinning, the fibers are cooled by ring blowing, oiled, first drawn, second drawn, and wound into shape to obtain antibacterial polyester fibers.

[0012] Step S5: The antistatic polyester fiber is warp-knitted and interwoven with the antibacterial and anti-mite cotton fiber obtained in step S2; then the antibacterial and anti-mite cotton fiber is warp-knitted and interwoven with hollow polyester fiber with a hollowness of 30-50%; then the hollow polyester fiber is warp-knitted and interwoven with the antibacterial polyester fiber obtained in step S4.

[0013] The present invention is further configured such that, in step S1, based on the total weight of the elastic yarn, the amount of spandex yarn used is 10-30 wt%, and the amount of nylon yarn used is 70-90 wt%.

[0014] The present invention is further configured such that, in step S1, the stretching length of the spandex filament is 250-300%, preferably 270%.

[0015] The present invention is further configured such that, in step S1, the twist of the nylon yarn wound around the outer surface of the stretched spandex yarn is 350 to 450, preferably 400.

[0016] The present invention is further configured such that the preparation of the antibacterial agent described in step S3 includes the following steps: using 4-vinylpyrrole and succinic acid as raw materials, and potassium persulfate as an initiator, the reaction is carried out at 120-140°C under a nitrogen atmosphere for 60-80 minutes; the unreacted 4-vinylpyrrole is distilled off under reduced pressure at 140°C to obtain a light brown solid antibacterial agent intermediate; then ethylene glycol is added as a hydroxyl-terminated modifier, and the reaction is carried out at 150-160°C for 1.5-2.0 hours; then the excess unreacted ethylene glycol is distilled off under reduced pressure at 185°C to prepare the desired antibacterial agent.

[0017] The present invention is further configured such that the molar ratio of succinic acid to 4-vinylpyrrole is 1:1.05 to 1:1.15, and the molar ratio of succinic acid to ethylene glycol is 1:2.5 to 1:3.5.

[0018] The present invention is further configured as follows: in the polycondensation reaction described in step S3, the atmospheric pressure ester is introduced into the polycondensation reactor through a polymerization pipeline, and then the antibacterial agent is added to the polycondensation reactor by means of online addition of the polycondensation pipeline in melt direct spinning, and polycondensation reaction is carried out with the atmospheric pressure ester; the final polycondensation reaction is carried out under high temperature and high vacuum conditions, and the antibacterial agent and the polyester esterified oligomer undergo transesterification reaction to prepare the desired antibacterial polyester masterbatch.

[0019] In summary, the present invention has the following beneficial effects:

[0020] 1. The antibacterial and anti-mite layer of the present invention is made of cotton fiber with strong water absorption. During the preparation process, it is treated with composite alkali solution, alkali solution, mercaptoacetic acid solution and silver nitrate solution in sequence, so that the antibacterial substance can be stably embedded in the fiber, rather than just attached to the surface of the fiber, and thus maintain good antibacterial performance even under multiple washing and long-term immersion.

[0021] 2. By incorporating antistatic polyester fibers, this invention avoids the problem of poor antistatic properties in warp-knitted lace fabrics. Furthermore, by using hollow polyester fibers as the hollow insulation layer material in conjunction with a functional insulation layer made of nylon elastic yarn, which has excellent skin-friendliness, this invention can improve both the insulation effect and the skin-friendliness of the fabric. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicating the orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "set up / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The present invention will now be described in detail.

[0026] A method for preparing an enhanced warp-knitted lace fabric includes the following steps: Step S1: Stretch spandex yarn to a certain stretch length, and then wrap nylon yarn evenly around the outer surface of the stretched spandex yarn with a certain twist to obtain nylon elastic covered yarn.

[0027] Step S2: First, the nylon elastic covered yarn is placed in a composite alkaline solution and treated at 60-75℃ for 20-40 minutes, then treated with alkaline solution at 50-65℃ for 12-18 minutes, and then washed; next, the treated nylon elastic covered yarn is placed in a mercaptoacetic acid solution and immersed at 170-185℃ for 35-45 minutes, and then washed and dried; then the nylon elastic covered yarn is activated under high temperature and high pressure, and finally placed in a silver nitrate solution and immersed at 95-110℃ for 30-50 minutes, and then washed and dried to obtain antibacterial and anti-mite cotton fiber;

[0028] Step S3: Using terephthalic acid and ethylene glycol as raw materials, terephthalic acid and ethylene glycol are pressurized and esterified to obtain polyester esterified product. Then, the polyester esterified product is subjected to atmospheric pressure esterification reaction to obtain atmospheric pressure esterified product. Then, the atmospheric pressure esterified product and antibacterial agent are subjected to polycondensation reaction to prepare antibacterial polyester masterbatch.

[0029] Step S4: The antibacterial polyester masterbatch and high-viscosity polyester chips prepared in step S3 are melt-blended and granulated using a twin-screw extruder to prepare antibacterial polyester chips, wherein the mass fraction of antibacterial polyester masterbatch in antibacterial polyester chips is 5-30%; the obtained antibacterial polyester chips are vacuum dried and pre-crystallized at 80℃ for 12h, and then crystallized at 120℃ for 12h. Then, by melt spinning, the fibers are cooled by ring blowing, oiled, first drawn, second drawn, and wound into shape to obtain antibacterial polyester fibers.

[0030] Step S5: The antistatic polyester fiber is warp-knitted and interwoven with the antibacterial and anti-mite cotton fiber obtained in step S2; then the antibacterial and anti-mite cotton fiber is warp-knitted and interwoven with hollow polyester fiber with a hollowness of 30-50%; then the hollow polyester fiber is warp-knitted and interwoven with the antibacterial polyester fiber obtained in step S4.

[0031] In step S1, based on the total weight of the elastic yarn, the amount of spandex yarn used is 10-30 wt%, and the amount of nylon yarn used is 70-90 wt%.

[0032] In step S1, the stretch length of the spandex filament is 250-300%, preferably 270%.

[0033] In step S1, the twist of the nylon yarn wound around the outer surface of the stretched spandex yarn is 350 to 450, preferably 400.

[0034] The preparation of the antibacterial agent in step S3 includes the following steps: using 4-vinylpyrrole and succinic acid as raw materials, and potassium persulfate as an initiator, the reaction is carried out at 120-140°C under a nitrogen atmosphere for 60-80 minutes. Unreacted 4-vinylpyrrole is distilled off under reduced pressure at 140°C to obtain a light brown solid antibacterial agent intermediate. Then, ethylene glycol is added as a hydroxyl-terminated modifier, and the reaction is carried out at 150-160°C for 1.5-2.0 hours. Finally, excess unreacted ethylene glycol is distilled off under reduced pressure at 185°C to prepare the desired antibacterial agent.

[0035] The molar ratio of succinic acid to 4-vinylpyrrole is 1:1.05 to 1:1.15, and the molar ratio of succinic acid to ethylene glycol is 1:2.5 to 1:3.5.

[0036] In step S3, the polycondensation reaction involves introducing the atmospheric pressure esterified material into the polycondensation reactor through a polymerization pipeline. Then, the antibacterial agent is added to the polycondensation reactor via an online addition method using melt direct spinning, and undergoes a polycondensation reaction with the atmospheric pressure esterified material. The final polycondensation reaction is carried out under high temperature and high vacuum conditions, and the antibacterial agent undergoes an ester exchange reaction with the polyester esterified oligomer to prepare the desired antibacterial polyester masterbatch.

[0037] The antibacterial and anti-mite layer of this invention is made of cotton fiber with strong water absorption. During the preparation process, it is treated with a composite alkali solution, an alkali solution, a mercaptoacetic acid solution and a silver nitrate solution in sequence, so that the antibacterial substances can be stably embedded in the fiber, rather than just attached to the surface of the fiber. Thus, it can maintain good antibacterial performance even under multiple washing and long-term immersion.

[0038] This invention avoids the problem of poor antistatic properties in warp-knitted lace fabrics by incorporating antistatic polyester fibers. At the same time, it combines hollow polyester fibers as the hollow insulation layer material with nylon elastic yarn as the raw material for the functional insulation layer, which has excellent skin-friendliness. This not only improves the insulation effect but also further enhances the skin-friendliness of the fabric.

[0039] Using elastic covered yarn obtained by evenly winding nylon yarn around the outer surface of stretched spandex yarn as the raw material for lace fabric production can significantly improve the elastic elongation of the yarn in the weft direction, so that the resulting lace fabric has good elasticity in both the transverse and longitudinal directions, and excellent extensibility in all directions.

[0040] In polyester polymerization, a pulping process is first performed, using ethylene glycol solution to dissolve and disperse terephthalic acid and added additives. This reduces the interfacial effect of the solid-liquid reaction, increases the esterification rate in the later polymerization stages, and avoids excessive reaction time and increased diethylene glycol byproducts due to a large solid-liquid interface, which would lead to a decline in product quality. Conventional esterification processes use atmospheric pressure, requiring high ethylene glycol content, which can lead to excessive ethylene glycol volatilization, resulting in inaccurate esterification and difficulty in process control. Excessive ethylene glycol volatilization also causes significant energy waste and increases diethylene glycol content, resulting in a yellowish product color. Therefore, excessive anti-etherifying agents are needed, further reducing product quality. In contrast, pressurized esterification increases the saturated vapor pressure of ethylene glycol, reducing excessive volatilization. This increases the contact concentration between terephthalic acid and ethylene glycol, ensuring reactivity and increasing the reaction rate.

[0041] Atmospheric pressure esterification refers to the process of introducing polyester esterification into a polycondensation reactor through a polymerization pipeline, and then reacting under atmospheric pressure with nitrogen as the protective gas at a reaction temperature of 245–255°C for 1.5–2.0 h. After the esterification reaction is completed, atmospheric pressure esterification is obtained.

[0042] Atmospheric pressure esterification is a process in which polyester esters are further esterified to form oligomers. Through atmospheric pressure esterification, the mono- and dimeric diethyl terephthalate is further esterified to form tri- and tetra-polymer structures. This ensures that the esterified structures available for transesterification during the polycondensation process are available, and also ensures that the viscosity is low in the early stages of the polycondensation process, which is conducive to the diffusion and removal of low molecular weight molecules. This facilitates the subsequent condensation process, especially the transesterification reaction, which is beneficial for antibacterial agents with terminal hydroxyl structures to undergo transesterification. This allows the pyrrole structure with antibacterial effect to be incorporated into the polyester chain segment, thereby improving the antibacterial properties of the polyester structure itself.

[0043] Previously used antibacterial agents for polyester fiber spinning mainly consisted of inorganic nano-zinc oxide, nano-cuprous oxide, and silver oxide. These inorganic antibacterial agents are inherently difficult to disperse during polymerization, and as heavy metal oxides, they also act as catalytic degradation agents in polyester polymerization and esterification. During high-temperature polymerization and spinning, accelerated polycondensation and rapid degradation often occur. Therefore, to avoid the impact of conventional inorganic nano-antibacterial agents on polyester itself, especially the mechanical properties of polyester fiber materials and the impact of antibacterial agent loss on service life, this application designs and prepares 4-vinylpyrrole molecules with polycondensation-reactive functional groups and antibacterial structures. Utilizing the reactive vinyl functional groups and antibacterial pyrrole functional groups in the 4-vinylpyrrole molecule, reactive carboxyl groups are introduced into the pyrrole functional groups through the reaction of the vinyl functional groups. The reactivity of the carboxyl groups allows the antibacterial pyrrole functional groups to be introduced into the molecular chain segments, thereby endowing excellent antibacterial properties and avoiding the dispersion difficulties caused by inorganic additives.

[0044] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an enhanced warp-knitted lace fabric, characterized in that: Including the following Steps: Step S1: Stretch the spandex yarn to a certain stretch length, and then evenly wrap the nylon yarn around the outer surface of the stretched spandex yarn with a certain twist to obtain nylon elastic covered yarn. Step S2: First, the nylon elastic covered yarn is placed in a composite alkaline solution and treated at 60-75℃ for 20-40 minutes, then treated with alkaline solution at 50-65℃ for 12-18 minutes, and then washed; next, the treated nylon elastic covered yarn is placed in a mercaptoacetic acid solution and immersed at 170-185℃ for 35-45 minutes, and then washed and dried; then the nylon elastic covered yarn is activated under high temperature and high pressure, and finally placed in a silver nitrate solution and immersed at 95-110℃ for 30-50 minutes, and then washed and dried to obtain antibacterial and anti-mite cotton fiber; Step S3: Using terephthalic acid and ethylene glycol as raw materials, terephthalic acid and ethylene glycol are pressurized and esterified to obtain polyester esterified product. Then, the polyester esterified product is subjected to atmospheric pressure esterification reaction to obtain atmospheric pressure esterified product. Then, the atmospheric pressure esterified product and antibacterial agent are subjected to polycondensation reaction to prepare antibacterial polyester masterbatch. Step S4: The antibacterial polyester masterbatch and high-viscosity polyester chips prepared in step S3 are melt-blended and granulated using a twin-screw extruder to prepare antibacterial polyester chips, wherein the mass fraction of antibacterial polyester masterbatch in antibacterial polyester chips is 5-30%; the obtained antibacterial polyester chips are vacuum dried and pre-crystallized at 80℃ for 12h, and then crystallized at 120℃ for 12h. Then, by melt spinning, the fibers are cooled by ring blowing, oiled, first drawn, second drawn, and wound into shape to obtain antibacterial polyester fibers. Step S5: The antistatic polyester fiber is warp-knitted and interwoven with the antibacterial and anti-mite cotton fiber obtained in step S2; then the antibacterial and anti-mite cotton fiber is warp-knitted and interwoven with hollow polyester fiber with a hollowness of 30-50%; then the hollow polyester fiber is warp-knitted and interwoven with the antibacterial polyester fiber obtained in step S4.

2. The method for preparing an enhanced warp-knitted lace fabric according to claim 1, characterized in that: In step S1, based on the total weight of the elastic yarn, the amount of spandex yarn used is 10-30 wt%, and the amount of nylon yarn used is 70-90 wt%.

3. The method for preparing an enhanced warp-knitted lace fabric according to claim 1, characterized in that: In step S1, the stretch length of the spandex filament is 250-300%, preferably 270%.

4. The method for preparing an enhanced warp-knitted lace fabric according to claim 1, characterized in that: In step S1, the twist of the nylon yarn wound around the outer surface of the stretched spandex yarn is 350 to 450, preferably 400.

5. The method for preparing an enhanced warp-knitted lace fabric according to claim 1, characterized in that: The preparation of the antibacterial agent described in step S3 includes the following steps: using 4-vinylpyrrole and succinic acid as raw materials, and potassium persulfate as an initiator, the reaction is carried out at 120-140°C under a nitrogen atmosphere for 60-80 minutes. Unreacted 4-vinylpyrrole is distilled off under reduced pressure at 140°C to obtain a light brown solid antibacterial agent intermediate. Then, ethylene glycol is added as a hydroxyl-terminated modifier, and the reaction is carried out at 150-160°C for 1.5-2.0 hours. Finally, excess unreacted ethylene glycol is distilled off under reduced pressure at 185°C to prepare the desired antibacterial agent.

6. The method for preparing an enhanced warp-knitted lace fabric according to claim 5, characterized in that: The molar ratio of succinic acid to 4-vinylpyrrole is 1:1.05 to 1:1.15, and the molar ratio of succinic acid to ethylene glycol is 1:2.5 to 1:3.

5.

7. The method for preparing an enhanced warp-knitted lace fabric according to claim 5, characterized in that: In step S3, the polycondensation reaction involves introducing the atmospheric pressure esterified material into the polycondensation reactor through a polymerization pipeline. Then, an antibacterial agent is added to the polycondensation reactor via an online addition pipeline for melt spinning, and the antibacterial agent reacts with the atmospheric pressure esterified material. The final polycondensation reaction is carried out under high temperature and high vacuum conditions, and the antibacterial agent reacts with the polyester esterified oligomer to prepare the desired antibacterial polyester masterbatch through transesterification.