A method for sweat-proof and crease-free finishing of cotton knitted fabric and a single-parent single-preventive sweat-proof and crease-free cotton knitted fabric prepared thereby

Abstract

The present application relates to the technical field of textile dyeing and finishing, and particularly relates to a single-parent single-proof cotton knitted fabric with sweat traceless function and a preparation method thereof. The method comprises the following steps: (1) pretreating the cotton fabric to obtain a base fabric; (2) preparing a printing paste; (3) applying the printing paste to the front side of the base fabric to perform local water-repellent finishing, and the back side of the dyed base fabric is not treated; (4) sequentially performing pre-drying and baking setting on the base fabric finished in step (3); (5) performing water washing and paste removing treatment on the base fabric after baking setting, and then drying to obtain a single-parent single-proof sweat traceless cotton knitted fabric with a hydrophobic front side and a hydrophilic back side. The present application solves the problems of the existing technology, i.e. the sweat absorption of cotton fabric is easy to leave traces, and the existing single-side water-proof technology is easy to penetrate and damage the skin-friendliness and has poor air permeability.

Description

Technical Field

[0001] This invention relates to the field of textile dyeing and finishing technology, specifically to a method for finishing cotton knitted fabrics to remove sweat residue and the resulting single-pair, sweat-resistant, and residue-free cotton knitted fabric. Background Technology

[0002] Cotton fabrics, with their skin-friendly softness, moisture absorption, breathability, and natural comfort, are widely used in everyday and formal clothing such as shirts, polo shirts, T-shirts, and business casual wear, making them one of the most widely used apparel fabrics. However, cotton fibers have a strong moisture absorption capacity, and absorbed sweat can leave noticeable dark wet stains on the fabric's surface. The significant difference in appearance between dry and wet areas can easily cause embarrassing situations and seriously affect the aesthetics and appropriateness of clothing, making it difficult to meet the requirements of a clean appearance in high-end business settings, commuting, social occasions, and light exercise.

[0003] Existing sweat-repellent technologies mainly focus on moisture-wicking and quick-drying, one-way moisture conduction, overall water-repellent finishing, optical diffuse reflection, and multi-layer composite structures. While these technologies have addressed the issue of wet marks to some extent, they all have significant limitations and cannot meet the needs of cotton fabrics. Traditional moisture-wicking and quick-drying fabrics can only increase the rate of moisture diffusion and evaporation, but cannot prevent moisture from penetrating to the outer layer of the fabric, so the problem of wet marks remains prominent. Publication number CN104074055A uses a combination of single-sided waterproof printing and dot matrix water-repellent technology, which achieves single-sided waterproofing and quick-drying, and can suppress wet marks, but it significantly reduces the breathability of the fabric, resulting in a stiff feel, stuffiness, and damage to the original comfort characteristics of cotton fabrics. Publication number CN121087678A relies on the optical diffuse reflection or quick-drying mechanism of TiO2 matte fibers to achieve sweat-repellent properties, but it has problems such as complex structural design, high difficulty in process control, and poor mass production stability, making it difficult to apply on a large scale to conventional cotton fabrics.

[0004] More significantly, existing single-sided functional control technologies generally suffer from insufficient precision. Most processes impart water repellency to the outer layer of the fabric through single-sided printing or coating; however, the waterproofing agent easily migrates and penetrates inwards along the yarn capillaries, causing the skin-contact surface to change from hydrophilic to hydrophobic. This undermines the core advantage of cotton fabrics being skin-friendly and comfortable, leading to problems such as roughness, lack of sweat absorption, and stickiness. Even technologies employing seepage-proof isolation methods suffer from drawbacks such as cumbersome processes, the need for multiple washing and degreasing, high costs, and difficulty in controlling the feel, failing to simultaneously achieve water repellency without leaving a trace, skin-friendly comfort, softness, breathability, and production stability. Furthermore, publication number CN206589408U uses a multi-layer composite structure to achieve single absorption and single waterproofing; the composite film layer significantly reduces the fabric's breathability and moisture permeability, resulting in stuffiness and stickiness when worn, which does not meet the needs of close-fitting clothing. Summary of the Invention

[0005] In response to the problems of existing technologies, such as cotton fabrics being prone to showing sweat marks and single-sided waterproofing technology being prone to penetration, damaging skin-friendliness and having poor breathability, this invention provides a method for finishing cotton fabrics to prevent sweat marks. The aim is to achieve water-repellent and stain-resistant properties on the front side of the cotton fabric and hydrophilic and moisture-absorbing properties on the back side, completely suppressing the appearance of wet marks, while retaining the original softness, breathability and skin-friendly comfort of the cotton fabric.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for finishing cotton knitted fabrics without leaving a sweat residue includes the following steps: (1) Pre-treating the cotton fabric to obtain a base fabric. Pre-treatment can effectively remove impurities from the fabric surface, providing a good base for subsequent finishing and ensuring the effective adhesion of the finishing agent. (2) Preparing a printing paste, wherein the printing paste contains a waterproofing agent, a crosslinking agent and a thickener, wherein the amount of thickener accounts for 0.5%-3% of the total mass of the printing paste, and the viscosity of the printing paste needs to be controlled at 15000-60000 mPa·s; by reasonably controlling the composition and viscosity of the printing paste, especially by precisely controlling the amount of thickener, the rheological properties of the paste can be effectively adjusted, avoiding excessive penetration of the waterproofing agent to the reverse side of the fabric during the finishing process, thereby ensuring that the hydrophilicity of the reverse side is not damaged. (3) Applying the printing paste to the front side of the base fabric for local water-repellent finishing by at least one of the following methods: scraping, magnetic rod printing or rotary screen printing, while leaving the reverse side of the base fabric untreated. This localized water-repellent finishing will form a discontinuous water-repellent area on the front side of the base fabric, with an area coverage of 40%-70%. Through this localized discontinuous water-repellent finishing, it can not only give the front side excellent hydrophobic and stain-resistant properties, but also retain the breathable pores of the unfinished area, ensuring the overall breathability and moisture permeability of the fabric and avoiding the stuffy feeling brought by the full coating. (4) The base fabric after step (3) is pre-dried and baked in sequence. By pre-drying, the moisture is removed and the initial form of the finishing agent is fixed. Then, by baking, the crosslinking agent reacts with the waterproofing agent and the fiber to form a strong network structure, which significantly improves the water-repellent effect and the washability. (5) The baked and shaped base fabric is washed and de-sizing, and then dried to obtain a single-sided, single-sided, sweat-proof, and seamless cotton fabric that is hydrophobic on the front side and hydrophilic on the back side. By washing away the unreacted sizing agent and thickener, the original soft hand feel of the cotton fabric can be restored, and finally a sweat-proof and seamless fabric with a stable asymmetrical structure can be obtained.

[0008] Preferably, the pretreatment process in step (1) is as follows: soaping with a detergent at a concentration of 5-10 g / L for 30 min, followed by washing with water at 50°C for 20-30 min, and finally dehydration and drying at 90-100°C. This standardized pretreatment process effectively removes impurities, improves fiber wettability, and creates favorable conditions for subsequent processing.

[0009] Preferably, in step (1), the cotton knitted fabric is pure white or dyed fabric with a specification of 180 ± 5 g / m².2 .

[0010] Preferably, in step (3), the specific process parameters for different application methods are as follows:

[0011] When using a scraping coating process, the amount of ink applied should be controlled at 10%-30% of the fabric weight, and the printing speed should be 10-30 m / min. When using a magnetic rod printing process, a magnetic rod with a diameter of 8-20 mm should be selected, and the printing speed should be 15-35 m / min. When using a rotary screen printing process, an 80-150 mesh rotary screen should be selected, and the ink penetration should be controlled at 20%-40%. By precisely controlling the parameters of different processes, the application of printing paste can be accurately achieved, ensuring the uniformity of the water-repellent area and the accuracy of the coverage.

[0012] As a preferred option, step (3) employs rotary screen printing to perform localized water-repellent finishing, controlling the area coverage of the water-repellent region to 45%-55%, while simultaneously controlling the amount of ink permeable to 30%. Rotary screen printing allows for more precise control of dot size and distribution, and the 45%-55% coverage and 30% ink permeability are key parameters for achieving the best balance between single-agent water repellency and breathability.

[0013] Preferably, the waterproofing agent is a fluorine-free waterproofing agent, specifically one or more of the following: modified polysiloxane (organosilicon polymer) TF-5910A, long-chain alkyl-modified polyurethane ZJ-M620-EA, and modified long-chain acrylate copolymer DM-3698; the crosslinking agent is one or more of the following: aliphatic polyurethane polymer RH-NB-SF14, aliphatic blocked isocyanate polymer TF-W294, and multifunctional reactive polymer (containing blocked isocyanate active groups) X-569A; the thickener is one or more of the following: polyacrylate synthetic thickener TF-313B, polyurethane thickener SN-8W, and hydroxyethyl cellulose QP-15000H. The above specific reagent combination can exert a synergistic effect, providing excellent waterproofing performance while ensuring good bonding with cotton fibers.

[0014] Preferably, in step (4): the pre-drying temperature is 80-110℃ and the pre-drying time is 1-2 min; the baking and shaping temperature is 130-170℃ and the baking time is 1-3 min. Suitable temperature and time parameters are key to ensuring that the cross-linking reaction proceeds fully without damaging the cellulose fibers.

[0015] Preferably, in step (5): the water washing and desizing process involves washing in clean water at 40-50℃ for 20-30 minutes; the drying temperature is 140-160℃ and the time is 1-2 minutes. Gentle water washing conditions can effectively remove residual slurry while avoiding damage to the cross-linked waterproof membrane.

[0016] This invention also provides a single-parent, single-sweat-resistant, seamless cotton knitted fabric prepared by the method described herein. The fabric has an asymmetrical single-parent, single-sweat-resistant structure, with its front side being a hydrophobic surface having a 40%-70% discontinuous water-repellent area, and its reverse side being a hydrophilic surface without waterproofing agent penetration. After 20 washes, the overall moisture management capacity (OMMC) value of the cotton fabric decreases by less than 2%. This fabric effectively restricts sweat penetration to the front side while maintaining extremely high wash resistance.

[0017] Preferably, the static water contact angle on the hydrophobic side of the cotton fabric is ≥ 127°, and the static water contact angle on the hydrophilic side is ≤ 45°; the wetting time on the hydrophobic side of the cotton fabric is greater than the wetting time on the hydrophilic side. The significant difference in contact angle and wetting time directly reflects the superior performance of the asymmetric structure.

[0018] Preferably, the waterproof rating of the hydrophobic side of the cotton knitted fabric reaches level 3 to 5, the wetting time of the hydrophobic side is 13s-29s, and the wetting time of the hydrophilic side is 4s-6s. The high waterproof rating and precise wetting time range ensure a sweat-free effect during actual wear.

[0019] The "sizing penetration rate of XX%" mentioned in this invention refers to the percentage of the sizing penetration depth to the total thickness of the fabric, achieved by adjusting the magnetic rod pressure or squeegee pressure of the rotary screen printing machine. This value can be observed and measured using a fabric cross-section microscope. The "area coverage rate of the water-repellent region" mentioned in this invention refers to the percentage of the water-repellent region to the total surface area of ​​the fabric, measured by an optical microscope combined with image processing software after printing and drying.

[0020] The viscosity of the printing paste defined in this invention is measured at an ambient temperature of 25°C using an NDJ-5S rotational viscometer, a No. 4 rotor, and a rotation speed of 6 rpm. By controlling the viscosity of the printing paste within this range, the fluidity of the paste during the printing process can be ensured to avoid clogging the screen, while also regulating the degree of diffusion of the paste on the fabric to guarantee the clarity of the outline of the water-repellent area. This ensures a stable water-repellent area coverage that meets the design requirements, without affecting the final finishing effect due to excessively high or low viscosity. The "20 washes" mentioned in this invention refers to machine washing at 40°C with standard detergent according to the 4N procedure specified in national standard GB / T 8629-2017; drying is performed after washing before subsequent performance testing. Clearly defining these test conditions ensures the consistency and reproducibility of the performance test results.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention precisely constructs an asymmetrical structure with a hydrophobic and stain-repellent front and a hydrophilic and moisture-absorbing back, inhibiting sweat migration and diffusion at the source to achieve a long-lasting and stable sweat-free effect. Utilizing a compound system of waterproofing agents, crosslinking agents, and thickeners, the penetration and migration of finishing agents are strictly controlled, significantly improving functional washability while preserving the soft feel, high breathability, and skin-friendly comfort of cotton fabrics. The process is simple and easy to control, suitable for continuous industrial production, and is environmentally friendly, safe, and applicable to a wide range of fabrics, greatly enhancing the aesthetic appeal and added value of high-end cotton fabrics. Attached Figure Description

[0023] Figure 1 This is the MMT unidirectional humidity pattern of sample-1 provided in Embodiment 1 of the present invention; Figure 2 This is the MMT unidirectional humidity pattern of sample-2 provided in Embodiment 2 of the present invention; Figure 3 This is the MMT unidirectional humidity pattern of sample-3 provided in Embodiment 3 of the present invention; Figure 4 This is the MMT unidirectional humidity pattern of sample-4 provided in Embodiment 4 of the present invention; Figure 5 This is the MMT unidirectional humidity pattern of sample-5 provided in Embodiment 5 of the present invention; Figure 6 This is a circular water droplet diagram of the hydrophilic / hydrophobic side of sample-3 provided in Embodiment 3 of the present invention; Figure 7 This is a diagram of the hydrophilic / hydrophobic elongated water droplet of sample-3 provided in Embodiment 3 of the present invention; Figure 8 This is a water contact angle diagram of the hydrophilic / hydrophobic side of sample-3 provided in Embodiment 3 of the present invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0025] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0026] The supplementary information on the raw materials used in this invention is as follows: TF-5910A, a fluorine-free waterproofing agent, is a modified polysiloxane (organosilicon polymer) produced by Zhejiang Chuanhua Chemical Group Co., Ltd.; ZJ-M620-EA, a fluorine-free waterproofing agent, is a modified polyurethane waterproofing agent containing long-chain alkyl groups, produced by Guangzhou Zhuangjie Chemical Co., Ltd.; DM-3698, a fluorine-free polyacrylate waterproofing agent, is produced by Guangdong Demei Fine Chemical Group Co., Ltd.; and RH-NB-SF14, a blocked polyisocyanate crosslinking agent, is produced by Ningbo Runhe High-Tech Materials Technology Co., Ltd. Crosslinking agent TF-W294 is a blocked isocyanate crosslinking agent, produced by Zhejiang Transfar Chemical Group Co., Ltd.; crosslinking agent X-569A is a multifunctional reactive polymer crosslinking agent containing blocked isocyanate active groups, produced by Fuco New Materials (Shanghai) Co., Ltd.; thickener TF-313B is a polyacrylate synthetic thickener, produced by Zhejiang Transfar Chemical Group Co., Ltd.; thickener SN-8W is a polyurethane thickener, produced by Shanghai Snow Chemical Technology Co., Ltd.; thickener QP-15000H is a hydroxyethyl cellulose thickener, produced by Dow Chemical Company. All of the above raw materials are existing commercially available products that can be stably procured, and those skilled in the art can obtain them according to their needs.

[0027] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0028] Example 1

[0029] This embodiment provides a method for finishing cotton knitted fabrics without leaving sweat marks, specifically including the following steps:

[0030] (1) Fabric type: Sky blue cotton knitted fabric (100% pure cotton knitted fabric, 180 g / m²) 2 );

[0031] (2) Preparation of printing paste: The printing paste formula is 25% fluorine-free waterproofing agent TF-5910A, 2% crosslinking agent TF-W294, 1.5% thickener TF-313B, and the balance is water, with a viscosity of about 50000 mPa·s.

[0032] (3) Magnetic rod coating waterproof finishing process: The waterproof finishing agent is evenly coated on the front side of the fabric (i.e. the outer waterproof side of the fabric). The amount of liquid coated is strictly controlled to be 18% of the weight of the fabric itself. During the coating process, the speed is kept stable at 25m / min to ensure that the water repellency coverage of the waterproof finishing agent on the front side of the fabric reaches 45%. The finishing agent is evenly attached to the fiber surface on the front side of the fabric to form a uniform water repellent coating. At the same time, the finishing agent is prevented from penetrating to the reverse side of the fabric (the skin-friendly and hydrophilic side) to ensure the single-acid and single-anti-water function of the fabric.

[0033] After the coating is completed, the fabric is pre-dried at 100℃ for 1 minute to remove moisture from the fabric surface and between fibers and fix the initial adhesion of the waterproofing agent. After the pre-drying, the fabric is immediately baked at 160℃ for 45 seconds. After washing and drying, the sweat-free fabric sample-1 is obtained.

[0034] Example 2

[0035] This embodiment provides a method for finishing cotton fabrics without leaving sweat residue, specifically including the following steps:

[0036] (1) Fabric type: Sky blue cotton knitted fabric (100% pure cotton knitted fabric, 180 g / m²) 2 );

[0037] (2) Preparation of printing paste: The printing paste formula is 25% fluorine-free waterproofing agent TF-5910A, 2% crosslinking agent TF-W294, 1.5% thickener TF-313B, and the balance is water, with a viscosity of about 50000 mPa·s.

[0038] (3) Magnetic rod coating waterproof finishing process: Use a magnetic rod with a diameter of 8 mm as the printing coating carrier. Apply the waterproof finishing agent evenly to the front side of the fabric (i.e. the waterproof side of the fabric) through magnetic rod printing. Strictly control the process parameters: the coating speed is kept stable at 22 m / min to ensure that the water repellency coverage of the waterproof finishing agent on the front side of the fabric reaches 50%, so that the finishing agent can penetrate evenly and adhere to the fiber surface on the front side of the fabric to form a dense and uniform water repellent printed coating. At the same time, strictly control the magnetic rod pressure and printing accuracy to prevent the waterproof finishing agent from penetrating to the reverse side of the fabric (the skin-friendly and hydrophilic side) and ensure that the single-acid and single-proof function of the fabric is not affected.

[0039] After the magnetic rod coating is completed, the fabric is subjected to pre-drying and baking treatment in sequence: the temperature is controlled at 90 ℃ and the pre-drying is carried out for 2 minutes to allow the waterproof finishing agent to initially adhere and fix to the fiber surface, preventing the coating from wrinkling or peeling during the subsequent baking process; after the pre-drying is completed, the baking process is immediately carried out, the baking temperature is set at 145 ℃ and the baking time is controlled at 1.5 minutes, and then the fabric is washed and dried to obtain sweat-free fabric sample-2.

[0040] Example 3

[0041] This embodiment provides a method for finishing cotton fabrics without leaving sweat residue, specifically including the following steps:

[0042] (1) Fabric type: Sky blue cotton knitted fabric (100% pure cotton knitted fabric, 180 g / m²) 2 );

[0043] (2) The composition of the printing paste is: 25% waterproofing agent TF-5910A, 2% crosslinking agent TF-W294, 1.5% thickener TF-313B, and the balance is water with a viscosity of about 50,000 mPa·s.

[0044] (3) Rotary screen printing waterproof finishing process: A 120 mesh rotary screen is selected to accurately transfer the printing paste to the front side of the fabric (i.e. the waterproof side of the fabric) through the rotary screen dots. The printing process parameters are strictly controlled: ensure that the water repellency coverage of the waterproof finishing agent on the front side of the fabric reaches 55%, and at the same time control the amount of paste penetration to 30%. This ensures that a uniform and dense water repellent dot coating is formed on the front side of the fabric to achieve the expected waterproof effect, while strictly controlling the amount of paste penetration to avoid excessive penetration of the waterproof finishing agent to the reverse side of the fabric (the skin-friendly and hydrophilic side).

[0045] After the printing process is completed, the fabric is subjected to pre-drying and baking treatment in sequence: the temperature is controlled at 95℃ and the pre-drying is carried out for 2 minutes to gradually remove the moisture from the fabric surface and the gaps between the fibers, so that the waterproof finishing agent can initially adhere to and fix on the fiber surface of the front side of the fabric, preventing problems such as wrinkling, peeling and bleeding of the coating during the subsequent baking process; after the pre-drying is completed, the baking process is immediately carried out, the baking temperature is set at 150℃ and the baking time is controlled at 1 minute, and then washed and dried to obtain sweat-free fabric sample-3.

[0046] Example 4

[0047] This embodiment provides a method for finishing cotton knitted fabrics without leaving sweat marks, specifically including the following steps:

[0048] (1) Fabric type: Sky blue cotton knitted woven fabric (100% pure cotton knitted fabric, 180 g / m²) 2 );

[0049] (2) The composition of the printing paste is: 25% waterproofing agent TF-5910A, 2% crosslinking agent TF-W294, 1.0% thickener TF-313B, and the balance is water with a viscosity of about 45000mPa·s.

[0050] (3) Rotary screen printing waterproof finishing process: 120 mesh rotary screen is selected, and the printing paste is accurately transferred to the front of the fabric (i.e. the waterproof side of the fabric) through the rotary screen dots. The printing process parameters are strictly controlled: ensure that the water repellency coverage of the waterproof finishing agent on the front of the fabric reaches 30%, and at the same time control the amount of paste penetration to 30%. The post-treatment is the same as in Example 3. After washing and drying, sweat-free fabric sample-4 is obtained.

[0051] Example 5

[0052] This embodiment provides a method for finishing cotton fabrics without leaving sweat residue, specifically including the following steps:

[0053] (1) Fabric type: Sky blue cotton knitted fabric (100% pure cotton knitted fabric, 180 g / m²) 2 );

[0054] (2) The composition of the printing paste is: 25% waterproofing agent TF-5910A, 2% crosslinking agent TF-W294, 2.5% thickener TF-313B, and the balance is water with a viscosity of about 60000mPa·s.

[0055] (3) Rotary screen printing waterproof finishing process: A 120 mesh rotary screen is selected to accurately transfer the printing paste to the front side of the fabric (i.e. the waterproof side of the fabric) through the rotary screen dots. The printing process parameters are strictly controlled to ensure that the water repellency coverage of the waterproof finishing agent on the front side of the fabric reaches 80%, while controlling the amount of paste penetration to 40%. The post-treatment is the same as in Example 3. After washing and drying, sweat-free fabric sample-5 is obtained.

[0056] Comparative Example 1

[0057] Comparison of ordinary pure cotton knitted fabric and dyed cotton knitted fabric of the same specification without any water-repellent finishing -1.

[0058] To verify the performance of the single-parent, single-sweat-resistant, seamless cotton knitted fabric prepared according to the present invention, the following tests were conducted on samples 1-5 prepared in Examples 1-5 and conventionally dyed cotton knitted fabric without any water-repellent finishing (Comparative Example-1):

[0059] (1) Dynamic liquid moisture transport performance test

[0060] According to the standard GB / T 21655.2-2019 Evaluation of the Moisture Absorption and Quick-Drying Properties of Textiles Part 2: Dynamic Moisture Transfer Method, the dynamic liquid moisture transfer performance of the single-parent waterproof fabric was tested. 0.22 mL of simulated sweat was accurately dropped onto the center of the upper surface as the test liquid, and the test was conducted continuously for 2 minutes under constant test conditions. The changes in wetting time, water absorption rate, wetting radius, and diffusion rate of both sides of the fabric were monitored in real time by upper and lower sensors. The core indicators such as cumulative unidirectional transfer capacity and overall moisture management capacity (OMMC value) were calculated to quantitatively characterize the single-parent waterproof functional characteristics of the fabric, which are characterized by rapid water absorption in the inner layer, unidirectional liquid conduction from the inside to the outside, and water repellency and non-re-seepage in the outer layer.

[0061] (2) Water contact angle test

[0062] The sample, which had been pretreated in a standard environment of 25℃ and 65% RH for 24 h, was fixed flat on the sample stage, ensuring that the hydrophilic side of the fabric was facing up and the waterproof side was facing down without wrinkles. A volume of (5.0±0.1) μL of deionized water was vertically dropped at the center of the upper surface using the instrument's micro-injection system. After the droplet stabilized for 3 s, the droplet image was acquired using the instrument's high-definition camera system. The static water contact angle value of the upper surface of the fabric was obtained by fitting the Young-Laplace equation or by calculating the angle method, thus quantitatively characterizing the hydrophilic properties and external waterproof performance.

[0063] (3) Waterproof rating test

[0064] According to the standard GB / T 4745-2012 "Test and Evaluation of Waterproof Performance of Textiles - Water Spray Method", the finished fabric is first cut into 18 cm × 18 cm samples. 250 mL of test water is poured into a funnel and sprayed continuously for 25–30 seconds. After spraying, the rating is based on the water wetting condition of the cotton fabric surface.

[0065] Table 1 shows the sweat-free performance indicators of the single-parent single-protection fabric samples 1-5 prepared in each embodiment and Comparative Example-1.

[0066] Table 1. Sweat-free performance indicators of the samples

[0067]

[0068] Combining the data in Table 1 and Figures 1-8 As can be seen from the test spectra, compared with Comparative Example-1, Examples 1-3 (Samples 1-3) of this application showed significantly superior performance in unidirectional moisture wicking and sweat-free properties.

[0069] In Examples 1-3, the hydrophobic contact angles were all ≥127°, achieving a waterproof rating of 3-5, while the hydrophilic contact angles were all ≤45°. Furthermore, the wetting time on the hydrophobic side (13.23s-28.17s) was significantly longer than that on the hydrophilic side (4.67s-5.34s). This demonstrates that the process of this invention successfully constructed a single-affinity, single-resistance structure with an inner hydrophilic layer and an outer hydrophobic layer. Microscopic mechanism analysis shows that the thickener (0.5%-3%) controls the paste viscosity at 15000-60000 mPa·s. During application, the rheological properties of this high-viscosity fluid limit the deep penetration of the waterproofing agent along the capillary of the cotton fibers, causing it to remain and crosslink on the front side of the fabric. Under high-temperature baking, the crosslinking agent promotes covalent bonding between the waterproofing agent molecules and the cellulose hydroxyl groups, forming a stable hydrophobic network. The fibers on the reverse side, which are not in contact with the waterproofing agent, retain their natural hydrophilic groups (hydroxyl groups).

[0070] Comparing Sample-3 (55% coverage), Sample-4 (30% coverage), and Sample-5 (80% coverage), it can be seen that the water-repellent area coverage is the key factor affecting overall performance. When the coverage is too low (Sample-4), the hydrophobic contact angle is only 96.3°, which is insufficient to resist sweat penetration. When the coverage is too high (Sample-5), the increased permeability causes some of the waterproofing agent to seep into the reverse side, causing the hydrophilic contact angle to soar to 102.4° and the hydrophilic wetting time to extend to 16.5s, severely compromising the sweat-absorbing ability of the skin-contact side. Sample-3, with a coverage of 45%-55%, achieved a hydrophobic contact angle as high as 143.2° and a hydrophilic contact angle of 36°, with an OMMC value as high as 0.91. This indicates that the 40%-70% (especially 45%-55%) discontinuous water-repellent area provides sufficient surface tension to prevent internal moisture from seeping out, while retaining enough untreated fibers as channels for the lateral diffusion of moisture. The two have a significant synergistic effect, achieving a perfect balance between moisture conduction and water repellency.

[0071] After 20 washes, the OMMC values ​​of Examples 1-3 all decreased by less than 4% (for example, Sample-3 decreased from 0.91 to 0.90, with a decrease rate of only 1.1%). This is due to the ternary compound system of waterproofing agent, crosslinking agent, and thickener. The network crosslinking film formed by the crosslinking agent on the fiber surface has extremely strong resistance to mechanical friction and hydrolysis, ensuring the stability of this asymmetric structure in long-term use.

Claims

1. A method for finishing cotton knitted fabrics without leaving sweat marks, characterized in that, The method includes the following steps: (1) pre-treating the cotton knitted fabric to obtain a base fabric; (2) preparing a printing paste, wherein the printing paste includes a waterproofing agent, a crosslinking agent and a thickener, wherein the amount of the thickener accounts for 0.5%-3% of the total mass of the printing paste, and the viscosity of the printing paste is controlled to be 15000-60000 mPa·s; (3) applying the printing paste to the front side of the base fabric for local water-repellent treatment by at least one of scraping, magnetic rod printing and rotary screen printing, and leaving the back side of the base fabric untreated; the local water-repellent treatment forms a discontinuous water-repellent area on the front side of the base fabric, and the area coverage of the water-repellent area is 40%-70%; (4) pre-drying and baking the base fabric treated in step (3) in sequence; (5) washing and de-pasteping the baked and shaped base fabric, and then drying it to obtain a single-sided, single-sided, sweat-proof, and seamless cotton fabric that is hydrophobic on the front and hydrophilic on the back.

2. The method for finishing cotton fabrics without leaving sweat residue according to claim 1, characterized in that, In step (1), the cotton knitted fabric is pure white or dyed fabric with a specification of 180 ± 5 g / m². 2 ; In step (3), the specific process parameters for different application methods are as follows: when using the scraping coating process, the liquid content is controlled to be 10%-30% of the fabric weight, and the machine speed is 10-30 m / min; when using the magnetic rod printing process, a magnetic rod with a diameter of 8-20 mm is selected, and the machine speed is 15-35 m / min; when using the rotary screen printing process, an 80-150 mesh rotary screen is selected, and the amount of ink penetration is controlled to be 20%-40%.

3. The method for finishing cotton fabrics without leaving sweat residue according to claim 1, characterized in that, In step (3), a rotary screen printing process is used to perform local water-repellent finishing. The area coverage of the water-repellent area is controlled at 45%-55%, and the amount of ink permeable to the printing paste is controlled at 30%.

4. The method for finishing cotton fabrics without leaving sweat marks according to claim 1, characterized in that: The waterproofing agent is one or a mixture of fluorine-free waterproofing agents TF-5910A, ZJ-M620-EA, and DM-3698; the crosslinking agent is one or a mixture of RH-NB-SF14, TF-W294, and X-569A; and the thickener is one or a mixture of TF-313B, PTF, and QP-15000H.

5. The method for finishing cotton fabrics without leaving sweat residue according to claim 1, characterized in that, In step (4): the pre-drying temperature is 80-110℃ and the pre-drying time is 1-2 min; the baking and shaping temperature is 130-170℃ and the baking time is 1-3 min.

6. The method for finishing cotton fabrics without leaving sweat residue according to claim 1, characterized in that, In step (5): the process of water washing and desizing is as follows: washing in clean water at 40-50℃ for 20-30 min; the drying temperature is 140-160℃ and the drying time is 1-2 min.

7. The method for finishing cotton knitted fabrics without leaving sweat marks according to claim 1, characterized in that, In step (1): the pretreatment process is as follows: soaping with detergent at a concentration of 5-10 g / L for 30 min, then washing with water at 50℃ for 20-30 min, and finally dehydrating and drying at 90-100℃.

8. A single-parent, sweat-resistant, seamless cotton knitted fabric prepared by the method according to any one of claims 1-7, characterized in that: The cotton knitted fabric has an asymmetrical single-acidity and single-resistance structure. Its front side is a hydrophobic surface with a 40%-70% discontinuous water-repellent area, and its back side is a hydrophilic surface that is free from water-repellent agent penetration. After 20 washes, the overall moisture management capacity (OMMC) value of the cotton knitted fabric decreases by less than 2%.

9. The single-parent, sweat-resistant, seamless cotton knitted fabric according to claim 8, characterized in that, The static water contact angle of the hydrophobic side of the front side of the cotton fabric is ≥ 127°, and the static water contact angle of the hydrophilic side of the reverse side is ≤ 45°; the wetting time of the hydrophobic side of the front side of the cotton fabric is greater than the wetting time of the hydrophilic side of the reverse side.

10. The single-parent, sweat-resistant, seamless cotton fabric according to claim 8, characterized in that, The waterproof rating of the hydrophobic side of the cotton knitted fabric reaches level 3 to 5, the wetting time of the hydrophobic side is 13s-29s, and the wetting time of the hydrophilic side is 4s-6s.

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