A method for preparing super-soft cotton fabric

Abstract

This invention relates to the field of nonwoven materials and engineering technology, and in particular to a method for preparing ultra-soft cotton fabric, comprising the following steps: greige fabric → pretreatment → mercerizing → dyeing → bio-enzyme treatment → softener treatment → calendering → finished product: desizing, scouring and bleaching are performed using a one-bath one-step impregnation method. The treatment solution consists of 4 g / L sodium hydroxide, 8 g / L hydrogen peroxide, 2 g / L scouring agent A-88C, and 4 g / L oxygen bleaching stabilizer LS 66. The bath ratio is 1:8, the treatment temperature is 95℃, and the treatment time is 90 min. Under the condition that the fabric elongation is 3-5%, it is treated with a sodium hydroxide solution of 200-250 g / L at a temperature of 50-70℃ and a machine speed of 20-30 m / min. The present invention reduces the crystallinity of the double filaments, increases smoothness and reduces friction, and provides excellent softness and durability. The addition of bio-enzymes and accelerators removes short fibers and reduces crystallinity. The softener is modified with a composite of hydroxyl silicone oil and waterborne polyurethane, which improves the adhesion and durability of the polyurethane. The isocyanate compound is also used. The small molecule polyurethane is easy to penetrate. The methyl ethyl ketone oxime end-capping is baked and decapped, and reacts with the hydroxyl silicone oil to increase durability.

Description

Technical Field

[0001] This invention relates to the field of nonwoven materials and engineering technology, and in particular to a method for preparing ultra-soft cotton fabric. Background Technology

[0002] Cotton fabrics are beloved by consumers for their excellent moisture absorption, breathability, softness, comfort, environmental friendliness, and skin-friendly properties. However, during processing, the fabric undergoes various dyeing, chemical, and mechanical processes under humid and hot conditions. These processes alter the fabric's structure and fiber morphology to some extent, resulting in a stiff and rough feel. As is well known, the softness of cotton fabrics is one of the most valued qualities by consumers. Improving the softness of a product not only enhances its competitiveness but also increases its added value and profitability.

[0003] The softening finishing of cotton fabrics mainly includes bio-enzymatic methods, physical-mechanical methods, and chemical methods. Bio-enzymatic methods primarily utilize cellulase to hydrolyze the fine fibers on the surface of cellulose fibers. Under certain external force, these fibers detach from the fibers, making the fabric surface smooth and improving its softness. Physical methods involve using various softening machines to treat the fabric through beating and kneading, changing the relative positions between fibers and yarns, thereby improving its bending rigidity and reducing frictional resistance to achieve a soft hand feel. Chemical methods use softeners to reduce the coefficient of friction between fibers to achieve a softening effect. Each of these three methods has its advantages and disadvantages when used individually. Bio-enzymatic and physical-mechanical methods are both energy-saving and environmentally friendly, but the former has a longer processing time and is prone to damaging fiber strength, while the latter has poor durability. Chemical methods are the most commonly used due to their simple process and high efficiency, but they mainly act on the fiber surface and are prone to shedding during use and washing, weakening or eliminating their effect.

[0004] Chinese patent discloses a unidirectional hydrophilic pure cotton fabric (publication number: CN 111186184 A) comprising a hydrophilic layer, a hydrophobic layer arranged closely adjacent to the hydrophilic layer, and multiple through holes penetrating the hydrophilic and hydrophobic layers. The through holes are trapezoidal, with the opening of the through hole in the hydrophilic layer being smaller than the opening in the hydrophobic layer. The upper diameter of the trapezoidal hole is 1–20 μm, and the ratio of the upper diameter to the lower diameter is 1:1.5–1:20. The water contact angle of the hydrophilic layer is 60.0–90.0 degrees, and the water contact angle of the hydrophobic layer is 93.0–148.0 degrees. However, this cotton fabric suffers from insufficient softness and poor durability, thus requiring a method for preparing an ultra-soft cotton fabric. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ultra-soft cotton fabric, thereby solving the problems of insufficient softness and poor durability of existing cotton fabrics.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for preparing ultra-soft cotton fabric, characterized by comprising the following steps: greige fabric → pretreatment → mercerizing → dyeing → bio-enzyme treatment → softener treatment → calendering → finished product: 1. A method for preparing an ultra-soft cotton fabric, characterized by comprising the following steps: (1) Preprocessing The desizing, scouring, and bleaching were carried out using a one-bath, one-step impregnation method. The treatment solution consisted of 4-6 g / L sodium hydroxide, 8-10 g / L hydrogen peroxide, 2-5 g / L scouring agent A-88C, and 4-6 g / L oxygen bleaching stabilizer LS 66. The bath ratio was 1:8, the treatment temperature was 90-100℃, and the treatment time was 85-95 min.

[0007] (2) Silky With a fabric elongation of 3-5%, the fabric is treated with a sodium hydroxide solution of 200-250 g / L at a temperature of 50-70℃ and a machine speed of 20-30 m / min. After the mercerized cotton fabric is neutralized and washed, it is then thoroughly washed, dried, and then mercerized a second time. The second mercerizing process is the same as the first mercerizing process.

[0008] (3) Staining The dyeing process was carried out using conventional reactive dyes.

[0009] (4) Bioenzyme treatment The pH of a solution containing 1-3 g / L polishing enzyme S-3500 and 10-20 g / L enzyme activity promoter was adjusted to 4.5±0.2 using acetic acid. The fabric was then immersed in the solution and treated at 50±0.5℃ for 40-60 min. The temperature was then raised to 80℃ to inactivate the polishing enzyme S-3500 for 10 min. The fabric was then thoroughly washed with water and dried.

[0010] (5) Softener treatment The softening process is achieved using a rolling and baking method.

[0011] Impregnating with softener solution → rolling → pre-drying (temperature 80~100℃, time 3~5min) → baking (temperature 150~180℃, time 3~5min) The softener treatment solution comprises hydroxyl silicone oil and waterborne polyurethane emulsion, with a mass ratio of hydroxyl silicone oil to waterborne polyurethane emulsion of 2:0.5-1, and a total softener concentration of 80-120 g / L in the treatment solution.

[0012] When impregnating with the softener treatment solution, the ultrasonic frequency in the ultrasonic cleaner is 50-60kHz and the ultrasonic power is 200-300W.

[0013] The aqueous polyurethane emulsion is prepared by the following steps. A method for preparing an aqueous polyurethane emulsion involves heating 30-50g of polydiol to melt, then cooling to 45-50℃ and adding 20-30g of diisocyanate. Under reflux, the temperature is raised to 50-60℃ and reacted for 20-30 minutes. Then, 0.5-1.5g of dibutyltin dilaurate and 10g of acetone are added, and the temperature is raised to 60-70℃ and the reaction continues for 15-30 minutes. Next, 5-10g of DMPA and 10-20g of acetone are added, and the temperature is raised to 80-90℃. After a constant temperature reaction for 10-20 minutes, 5-10g of methyl ethyl ketone oxime is added for end-capping reaction for 20-30 minutes. The temperature is then lowered to 45-50℃, and 0.3-1g of antioxidant and 3-5g of triethylamine are added. The neutralization reaction is carried out for 30 minutes. Finally, DMPA containing 1g / L of defoamer is slowly added dropwise. After the water-in-oil phase transition is completed, the remaining deionized water containing defoamer is quickly added to the 8317 deionized water, and emulsification continues to obtain a waterborne polyurethane emulsion.

[0014] (6) Calendering The process is performed using conventional calendering.

[0015] Preferably, the enzyme activity promoter is one of PEG2000, Tween 80, sorbitol and sodium lignosulfonate, with PEG2000 being the most preferred.

[0016] Preferably, the hydroxyl silicone oil is one of monohydroxyl-terminated polydimethylsiloxane and dihydroxyl-terminated polydimethylsiloxane, with dihydroxyl-terminated polydimethylsiloxane being more preferred.

[0017] Preferably, the polydiol is any one of polycaprolactone diol (PCL), polyether diol (PPG), and polytetrahydrofuran diol (PTMEG), with polycaprolactone diol (PCL) being the most preferred.

[0018] Preferably, the diisocyanate is one or a mixture of several of hexamethylene diisocyanate, diphenylmethane diisocyanate, pentamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and more preferably a mixture of pentamethylene diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, with a molar ratio of 4:6 between the two.

[0019] Preferably, the waterborne polyurethane has a weight-average molecular weight of 10,000 to 15,000; and the solid content of the waterborne polyurethane emulsion is 25%.

[0020] Preferably, the ultrasonic cleaning machine includes an immersion tank housing. The top of the immersion tank housing has an upper edge plate, and support legs are provided on all four sides of the outer wall of the upper edge plate. Side plates are provided on all four sides of the immersion tank housing, with a handle groove on one side of each side plate. Multiple ultrasonic generators are arranged in an equally spaced array at the bottom of the immersion tank housing. A power supply is located at the bottom of each ultrasonic generator, and a support plate is located at the bottom of the power supply. A heating tube is located on one side inside the immersion tank housing, and a bent step structure is provided at the top of the heating tube. Through the synergy of the arrayed transducer layout and the bent step structure, the uniformity of the sound field and micro-flow disturbance in the cleaning medium are improved, enhancing the cleaning and wetting capabilities on fabric surfaces and pores. The heating element allows for adjustable medium temperature, which helps soften stains, promotes chemical reactions and diffusion, and improves cleaning efficiency and consistency. The combination of the handle groove and support legs ensures both portability and operational stability, facilitating transfer and fixed use between different workstations. The overall modular structure facilitates maintenance and repair, and reduces the risk of machine downtime due to partial failures.

[0021] Preferably, the support leg has a shock-absorbing foot at its bottom, the shock-absorbing foot including a base, a support column at the top center of the base, a shock-absorbing spring sleeved on the support column, a guide sleeve sleeved on the outer wall of the shock-absorbing spring, the guide sleeve being associated with the support column, and an observation window on the outer wall of the guide sleeve. The shock-absorbing spring absorbs the vibration energy generated during equipment operation, reducing structural noise and mechanical impact transmitted to the ground and frame, improving the quietness and stability of the working environment; the guide sleeve ensures the stable operation of the spring in the vertical direction, avoiding lateral displacement and uneven wear, extending the service life of the shock-absorbing components; the observation window facilitates rapid inspection and condition assessment, timely detection of spring fatigue or abnormal displacement, and improves the maintainability and reliability of the equipment.

[0022] Preferably, a control panel is installed on the upper edge plate, and the control panel is equipped with control buttons. This centralizes and front-end the operation interface, enabling one-click operation and intuitive control, reducing operational complexity and the risk of misoperation; it also reserves hardware interfaces and operational space for future functional expansion (such as adding cleaning programs or linkage control), which is beneficial for equipment iteration and upgrades.

[0023] Preferably, a water supply pipe joint is provided through the outer wall of the side plate and the bottom of the immersion tank. This enables rapid connection and pipeline switching, facilitating flexible switching between different water sources or treatment stations, and improving equipment adaptability and versatility. The through-connection facilitates smooth media introduction and stable supply, reduces pipeline stagnation and air resistance, and ensures the continuity and consistency of the cleaning process. Placing the joint at the junction of the side plate and the bottom facilitates sealed installation and space optimization, while shortening the media path and reducing pressure drop and energy consumption.

[0024] The advantages of this invention are: This invention improves fabric softness through mercerizing in two main ways: firstly, by reducing fiber crystallinity; and secondly, the smooth surface of mercerized fibers reduces friction between fibers and yarns, thus enhancing softness. Compared to a single mercerizing process, a double mercerizing process results in fabrics with lower crystallinity and better durability of the mercerizing effect. Lower crystallinity leads to a higher content of amorphous regions, which not only improves fabric softness but also facilitates the penetration of auxiliaries into the fiber interior, further enhancing their softening effect. Furthermore, this invention performs a second mercerizing process after the first mercerizing and drying, achieving the lowest possible crystallinity and superior, longer-lasting luster.

[0025] Cellulase can not only remove short fibers from the surface of yarns or fabrics, but also reduce fiber crystallinity, thereby improving fabric softness. This invention incorporates an enzyme activity promoter during the bio-enzyme treatment process, further improving the treatment effect.

[0026] In the softener treatment process: First, the fabric is modified by composite modification with hydroxyl silicone oil and waterborne polyurethane emulsion. The excellent adhesion properties of polyurethane are utilized to improve the durability of the softening effect.

[0027] Secondly, the preparation of waterborne polyurethane emulsion uses a compound of hexamethylene diisocyanate and 4,4'-dicyclohexylmethane diisocyanate as the isocyanate. The principle is mainly that: hexamethylene diisocyanate molecules have a chain structure, which can give polyurethane good flexibility, while 4,4'-dicyclohexylmethane diisocyanate can appropriately improve its abrasion resistance in fabric use without affecting the flexibility of polyurethane.

[0028] Furthermore, the waterborne polyurethane emulsion of this invention has a relatively small polyurethane molecular weight, making it easy to penetrate into the fiber interior. In addition, the unreacted isocyanate groups are capped with methyl ethyl ketone oxime, which can be decapsulated during the baking stage of the softener finishing process. The released isocyanate groups can react with the hydroxyl groups in the hydroxyl silicone oil to generate a high molecular weight hydroxyl silicone oil copolymer polyurethane, which can significantly improve the durability of the softening effect.

[0029] Finally, an ultrasonic cleaner was installed in the softener impregnation tank, which not only improves the uniformity of emulsion dispersion, but also allows auxiliary finishing agents to penetrate into the fiber interior, thereby improving the uniformity and long-term stability of the treatment effect.

[0030] The ultrasonic cleaner utilizes an array of ultrasonic generators and a bent-step structure to enhance sound field uniformity and micro-flow disturbance, thereby improving fabric cleaning and wetting capabilities. The adjustable heating element softens stains and promotes reaction diffusion, improving cleaning efficiency and consistency. A handle groove paired with shock-absorbing support legs ensures both portability and stability. Shock-absorbing springs reduce vibration and noise, guide sleeves prevent misalignment, and an observation window facilitates inspection, enhancing reliability. A front-mounted control panel on the upper edge panel provides centralized buttons for one-button operation, reducing accidental operation and allowing for future expansion. A through-type water supply connector between the side panel and bottom allows for quick switching between water source positions. This through-type design ensures smooth media flow, reduces air resistance, and provides excellent sealing, saving space and reducing energy consumption, comprehensively improving cleaning performance, stability, and adaptability. Combined with a calendering process, the softness of fabrics is further enhanced. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall process structure of the present invention.

[0033] Figure 2 For the present invention Figure 1 Enlarged view of I in the middle.

[0034] Figure 3 This is a schematic diagram of the right-side structure of the present invention.

[0035] Figure 4 This is a top view of the structure of the present invention.

[0036] In the diagram: 1. Control panel; 2. Upper edge plate; 3. Support leg; 4. Handle groove; 5. Bent step structure; 6. Heating tube; 7. Immersion tank body; 8. Water supply pipe joint; 9. Side plate; 10. Guide sleeve; 11. Shock-absorbing spring; 12. Support column; 13. Ultrasonic generator; 14. Power supply; 15. Support plate. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1 Please see Figures 1-4 As shown, a method for preparing an ultra-soft cotton fabric is characterized by the following steps: greige fabric → pretreatment → mercerizing → dyeing → bio-enzyme treatment → softener treatment → calendering → finished product: (1) Preprocessing The desizing, scouring, and bleaching were carried out using a one-bath, one-step impregnation method. The treatment solution consisted of 4 g / L sodium hydroxide, 8 g / L hydrogen peroxide, 2 g / L scouring agent A-88C, and 4 g / L oxygen bleaching stabilizer LS 66. The bath ratio was 1:8, the treatment temperature was 95℃, and the treatment time was 90 min.

[0039] (2) Silky With a fabric elongation of 4%, the fabric is treated with a 220 g / L sodium hydroxide solution at a temperature of 60°C and a machine speed of 20 m / min. After neutralization and washing, the mercerized cotton fabric is thoroughly washed, dried, and then mercerized a second time. The second mercerizing process is the same as the first mercerizing process.

[0040] (3) Staining The dyeing process was carried out using conventional reactive dyes.

[0041] (4) Bioenzyme treatment The pH of a solution containing 3 g / L polishing enzyme S-3500 and 10 g / L enzyme activity promoter was adjusted to 4.5 ± 0.2 using acetic acid. The fabric was then immersed in the solution and treated at 50 ± 0.5 °C for 60 min. The temperature was then raised to 80 °C to inactivate the polishing enzyme S-3500 for 10 min, followed by thorough washing with water.

[0042] (5) Softener treatment The softening process is achieved using a rolling and baking method.

[0043] Impregnating with softener solution → rolling → pre-drying (temperature 90℃, time 4 min) → baking (temperature 160℃, time 5 min) The softener treatment solution comprises hydroxyl silicone oil and waterborne polyurethane emulsion, with a mass ratio of hydroxyl silicone oil to waterborne polyurethane emulsion of 2:1, and a total softener concentration of 100 g / L in the treatment solution.

[0044] When the softener treatment solution is used, the ultrasonic frequency in the ultrasonic cleaner is 55kHz and the ultrasonic power is 200W.

[0045] The aqueous polyurethane emulsion is prepared by the following steps. A method for preparing an aqueous polyurethane emulsion involves heating and melting 35g of polycaprolactone diol (PCL), then cooling the mixture to 50°C and adding 25g of diisocyanate (the molar ratio of pentamethylene diisocyanate to 4,4'-dicyclohexylmethane diisocyanate is 4:6). The mixture is then heated to 60°C under reflux and reacted for 20 minutes. Next, 1.0g of dibutyltin dilaurate and 10g of acetone are added, and the mixture is heated to 70°C and reacted for another 30 minutes. Then, 8g of DMPA and 15g of acetone are added, and the mixture is heated to 80°C and reacted at this constant temperature for 20 minutes. Finally, 10g of methyl ethyl ketone oxime is added for end-capping reaction for 30 minutes. The mixture is then cooled to 50°C, and 0.3g of antioxidant and 5g of triethylamine are added. The mixture is neutralized for 30 minutes, and then DMPA containing 1g / L of defoamer is slowly added dropwise. After the water-in-oil phase transition is completed, the remaining deionized water containing defoamer is quickly added to the 8317 deionized water, and emulsification continues to obtain a waterborne polyurethane emulsion.

[0046] In this embodiment, the enzyme activity promoter is one of PEG2000, Tween 80, sorbitol and sodium lignosulfonate, preferably PEG2000.

[0047] In this embodiment, the hydroxyl silicone oil is one of monohydroxyl-terminated polydimethylsiloxane and dihydroxyl-terminated polydimethylsiloxane, preferably dihydroxyl-terminated polydimethylsiloxane; the polydiol is any one of polycaprolactone diol (PCL), polyether diol (PPG), and polytetrahydrofuran diol (PTMEG), preferably polycaprolactone diol (PCL).

[0048] In this embodiment, the diisocyanate is one or a mixture of several of hexamethylene diisocyanate, diphenylmethane diisocyanate, pentamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, preferably a mixture of pentamethylene diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, with a preferred molar ratio of 4:6; the waterborne polyurethane has a weight-average molecular weight of 10,000 to 15,000, preferably 10,000; and the solid content of the waterborne polyurethane emulsion is 25%.

[0049] (6) Calendering The process is performed using conventional calendering.

[0050] 1. The effect of mercerization on fabric properties Comparative Example 1 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that mercerizing is not performed.

[0051] Comparative Example 2 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that a mercerizing treatment is performed.

[0052] Performance testing: Softness performance is standardized using the softness index, which is determined according to the T / CTES1017-2019 standard "Textiles - Methods for Testing and Evaluation of Fabric Touch - Three-Point Beam Method" using a textile material hand feel tester. The fabric is washed according to the GB / T 3921-2008 standard "Textiles - Tests for Color Fastness to Soap Washing". Crystallinity is tested using X-ray diffraction. Gloss is measured according to the FZ / T 01097—2006 standard "Test Methods for Fabric Gloss" using a CS-380 color spectrophotometer.

[0053] Table 1. Effects of mercerization on fabric properties

[0054] As shown in Table 1, the crystallinity of mercerized fabric is significantly lower than that of unmercerized fabric, and the crystallinity of double-mercerized fabric is lower than that of single-mercerized fabric. Table 2 also shows that the softness index and luster of double-mercerized fabric are significantly better than those of unmercerized fabric, and the softness index and luster of double-mercerized fabric are superior to those of single-mercerized fabric. Furthermore, compared with unwashed fabric, after 50 washes, the decrease in softness index and luster of double-mercerized fabric is significantly smaller than that of single-mercerized fabric.

[0055] 2. Effects of bio-enzyme treatment on fabric properties Comparative Example 3 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that no biological enzyme treatment is performed.

[0056] Comparative Example 4 This comparative example provides a method for preparing ultra-soft cotton fabric, as detailed in Example 1, except that the enzyme activity promoter PEG2000 was not added during the bio-enzyme treatment.

[0057] Performance testing: Softness performance is standardized using the softness index, which is determined according to the T / CTES1017-2019 standard "Textile Fabric Touch Test and Evaluation Method Three-Point Beam Method" using a textile material hand feel style tester. Crystallinity is tested using X-ray diffraction. Gloss is measured according to the FZ / T 01097—2006 standard "Test Method for Fabric Gloss" using a CS-380 color spectrum gloss meter.

[0058] Table 2 Effects of bio-enzyme treatment on fabric properties

[0059] As shown in Table 2, bio-enzyme treatment not only improves the luster of the fabric but also enhances its softness and slightly reduces its crystallinity. Furthermore, the fabric treated with PEG2000 (Example 1) has a slightly higher softness index and luster than the fabric not treated with PEG2000, while its crystallinity is slightly lower, indicating that PEG2000 promotes the bio-enzyme activity.

[0060] 3. The effect of softeners on the softness of fabrics Comparative Example 5 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that the softener is a dihydroxy-terminated polydimethylsiloxane.

[0061] Comparative Example 6 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that the softener is an aqueous polyurethane emulsion.

[0062] Comparative Example 7 This comparative example provides a method for preparing ultra-soft cotton fabric, specifically referring to Example 1, except that the weight-average molecular weight of polyurethane in the waterborne polyurethane emulsion is 20,000.

[0063] Comparative Example 8 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that the weight-average molecular weight of the polyurethane in the waterborne polyurethane emulsion is 5000.

[0064] Comparative Example 9 This comparative example provides a method for preparing ultra-soft cotton fabric, as detailed in Example 1, except that the polyurethane in the waterborne polyurethane emulsion is not end-capped with methyl ethyl ketone oxime.

[0065] Performance testing: The softness performance is standardized using the softness index, which is based on the T / CTES1017-2019 standard "Textiles - Methods for Testing and Evaluation of Tactile Feel of Fabrics - Three-Point Beam Method". The softness index of the fabric is tested using a textile material hand feel style tester. The fabric is washed according to the GB / T 3921-2008 standard "Textiles - Tests for Color Fastness to Soap Washing".

[0066] Table 3. Effects of softeners on fabric softness properties

[0067] As shown in Table 3, the fabric prepared in Example 1 has a softness index superior to Comparative Examples 5, 6, 7, 8, and 9 after both unwashed and 50 washes. When using dihydroxy-terminated polydimethylsiloxane as the softener alone (Comparative Example 5), the fabric prepared with this softener has a better softness index than the fabric prepared using polyurethane as the softener alone (Comparative Example 6), although the softness index of Comparative Example 5 changes significantly before and after washing. This indicates that polyurethane contributes less to fabric softness than dihydroxy-terminated polydimethylsiloxane, but it can improve the durability of the softening effect.

[0068] Table 3 also shows that the weight-average molecular weight of polyurethane has a certain impact on both softness and wash resistance. When the weight-average molecular weight is too high (Comparative Example 7), polyurethane has difficulty penetrating into the fiber interior and easily forms a film on the fiber surface, and the film formed has a relatively high hardness. When the weight-average molecular weight is too low (Comparative Example 8), although polyurethane can penetrate into the fiber interior well, the film formed has a low hardness and is easily damaged and detached from the fiber surface during washing. In addition, the polyurethane-treated fabric without methyl ethyl ketone oxime end-capping (Comparative Example 9) has poor wash resistance because the un-end-capped polyurethane cannot react with dihydroxy-terminated polydimethylsiloxane to form a macromolecule during softening treatment, and the film formed is easily damaged and detached from the fiber surface during washing.

[0069] 4. The effect of calendering on fabric properties Comparative Example 10 This comparative example provides a method for preparing an ultra-soft cotton fabric, as detailed in Example 1, except that no calendering treatment is performed.

[0070] Performance testing: Softness performance is standardized using the softness index, which is based on the T / CTES1017-2019 standard "Textile Fabric Tactile Testing and Evaluation Methods - Three-Point Beam Method". The softness index of the fabric is tested using a textile material hand feel style tester. Gloss is measured using a CS-380 color spectrum gloss meter, according to the FZ / T 01097—2006 standard "Test Method for Fabric Gloss".

[0071] Table 4. Effects of calendering on fabric properties

[0072] As shown in Table 4, calendering can significantly improve the luster of the fabric and also improve its softness. This is because during calendering, pressure and heat act on the fabric surface, further improving the smoothness of the fabric surface, significantly reducing roughness, and making it feel smoother and softer to the touch.

[0073] In this embodiment, the ultrasonic cleaning machine includes an immersion tank body 7. The top of the immersion tank body 7 is provided with an upper edge plate 2. Support legs 3 are provided on all four sides of the outer wall of the upper edge plate 2. Side plates 9 are provided on all four sides of the immersion tank body 7. A handle groove 4 is provided on one side of each side plate 9. Multiple ultrasonic generators 13 are arranged in an equally spaced array at the bottom of the immersion tank body 7. A power supply 14 is located at the bottom of each ultrasonic generator 13. A support plate 15 is located at the bottom of the power supply 14. A heating tube 6 is located on one side inside the immersion tank body 7. A bent step structure 5 is provided at the top of the heating tube 6 in the immersion tank body 7. Through the synergy of the array transducer layout and the bent step structure 5, the uniformity of the sound field and micro-flow disturbance in the cleaning medium are improved, enhancing the cleaning and wetting capabilities on the fabric surface and pores. The heating element 6 allows for adjustable medium temperature, which helps soften stains, promotes chemical reactions and diffusion, and improves cleaning efficiency and consistency. The combination of the handle groove 4 and the support leg 3 balances the portability and operational stability of the equipment, making it easy to move and fix between different workstations. The overall structure is clearly modular, which facilitates maintenance and repair, and reduces the risk of machine downtime due to partial failure.

[0074] In this embodiment, the support leg 3 has a shock-absorbing foot at its bottom, which includes a base. A support column 12 is located at the center of the top of the base. A shock-absorbing spring 11 is sleeved on the support column 12. A guide sleeve 10 is sleeved on the outer wall of the shock-absorbing spring 11. The guide sleeve 10 is associated with the support column 12, and an observation window is provided on the outer wall of the guide sleeve 10. The shock-absorbing spring 11 absorbs the vibration energy generated by the operation of the equipment, reducing the structural noise and mechanical impact transmitted to the ground and the frame, and improving the quietness and stability of the working environment. The guide sleeve 10 ensures the stable operation of the spring in the vertical direction, avoiding lateral displacement and uneven wear, and extending the service life of the shock-absorbing components. The observation window facilitates quick inspection and condition assessment, allowing for timely detection of spring fatigue or abnormal displacement, and improving the maintainability and reliability of the equipment.

[0075] In this embodiment, a control panel 1 is installed on the upper edge plate 2, and the control panel 1 is equipped with control buttons. This centralized and front-end operation interface enables one-click operation and intuitive control, reducing operational complexity and the risk of misoperation. It also reserves hardware interfaces and operational space for future functional expansion (such as adding cleaning programs or linkage control), facilitating equipment upgrades and iterations.

[0076] In this embodiment, a water supply pipe connector 8 is provided through the outer wall of the side plate 9 and the bottom of the immersion tank 7. This enables rapid connection and pipeline switching, facilitating flexible switching between different water sources or treatment stations and improving equipment adaptability and versatility. The through-connection facilitates smooth media introduction and stable supply, reduces pipeline stagnation and air resistance, and ensures the continuity and consistency of the cleaning process. Placing the connector at the junction of the side plate 9 and the bottom facilitates sealed installation and space optimization, while shortening the media path and reducing pressure drop and energy consumption.

[0077] Example 2 Please see Figures 1-4 As shown, a method for preparing an ultra-soft cotton fabric is characterized by the following steps: greige fabric → pretreatment → mercerizing → dyeing → bio-enzyme treatment → softener treatment → calendering → finished product: (1) Preprocessing The desizing, scouring and bleaching were carried out using a one-bath, one-step impregnation method. The treatment solution consisted of 5 g / L sodium hydroxide, 9 g / L hydrogen peroxide, 3 g / L scouring agent, and 5 g / L oxygen bleaching stabilizer. The bath ratio was 1:8, the treatment temperature was 90℃, and the treatment time was 95 min.

[0078] (2) Silky With a fabric elongation of 5%, the fabric is treated with a 200 g / L sodium hydroxide solution at a temperature of 70°C and a machine speed of 30 m / min. After neutralization and washing, the mercerized cotton fabric is thoroughly washed, dried, and then mercerized a second time. The second mercerizing process is the same as the first mercerizing process.

[0079] (3) Staining The dyeing process was carried out using conventional reactive dyes.

[0080] (4) Bioenzyme treatment The pH of a solution containing 2 g / L polishing enzyme and 15 g / L enzyme activity promoter was adjusted to 4.5 ± 0.2 using acetic acid. The fabric was then immersed in the solution and treated at 50 ± 0.5℃ for 60 min. The temperature was then raised to 80℃ to inactivate the polishing enzyme S-3500 for 10 min. The fabric was then thoroughly washed with water and dried.

[0081] (5) Softener treatment The softening process is achieved using a rolling and baking method.

[0082] Impregnating with softener solution → rolling → pre-drying (temperature 100℃, time 3 min) → baking (temperature 180℃, time 5 min) The softener treatment solution comprises hydroxyl silicone oil and waterborne polyurethane emulsion, with a mass ratio of hydroxyl silicone oil to waterborne polyurethane emulsion of 2:0.8, and a total softener concentration of 120 g / L in the treatment solution.

[0083] When the softener treatment solution is applied, the ultrasonic frequency in the ultrasonic cleaner is 55kHz and the ultrasonic power is 250W.

[0084] The aqueous polyurethane emulsion is prepared by the following steps. A method for preparing an aqueous polyurethane emulsion involves heating 40g of polydiol to melt, cooling it to 50°C, adding 30g of diisocyanate, and reacting at 60°C for 30 minutes under reflux. Then, 1.5g of dibutyltin dilaurate and 10g of acetone are added, and the mixture is heated to 65°C and reacted for another 30 minutes. Next, 10g of DMPA and 20g of acetone are added, and the mixture is heated to 90°C and reacted at a constant temperature for 10 minutes. Then, 8g of methyl ethyl ketone oxime is added for end-capping reaction for 25 minutes. The mixture is cooled to 45°C, and 0.5g of antioxidant and 4g of triethylamine are added. The mixture is neutralized for 30 minutes. Deionized water containing 1g / L of defoamer DM 8317 is slowly added dropwise. After the oil-in-water phase inversion is complete, the remaining deionized water containing the defoamer is quickly added, and emulsification continues to obtain the aqueous polyurethane emulsion.

[0085] (6) Calendering The process is performed using conventional calendering.

[0086] In this embodiment, the enzyme activity promoter is one of PEG2000, Tween 80, sorbitol and sodium lignosulfonate, preferably PEG2000.

[0087] In this embodiment, the hydroxyl silicone oil is one of monohydroxyl-terminated polydimethylsiloxane and dihydroxyl-terminated polydimethylsiloxane, preferably dihydroxyl-terminated polydimethylsiloxane; the polydiol is any one of polycaprolactone diol (PCL), polyether diol (PPG), polyether diol (PTMG), and polytetrahydrofuran diol (PTMEG), preferably polycaprolactone diol (PCL); the diisocyanate is hexamethylene diisocyanate or diphenylmethane diisocyanate. The waterborne polyurethane emulsion contains one or more of the following: ester, pentamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, preferably a mixture of pentamethylene diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, with a preferred molar ratio of 4:6; the waterborne polyurethane has a weight-average molecular weight of 10,000 to 15,000, preferably 10,000; and the solid content of the waterborne polyurethane emulsion is 25%.

[0088] (6) Calendering The process is performed using conventional calendering.

[0089] The rest of the content is the same as in Example 1.

[0090] Example 3 Please see Figures 1-4 As shown, a method for preparing an ultra-soft cotton fabric is characterized by the following steps: greige fabric → pretreatment → mercerizing → dyeing → bio-enzyme treatment → softener treatment → calendering → finished product: (1) Preprocessing The desizing, scouring, and bleaching were carried out using a one-bath, one-step impregnation method. The treatment solution consisted of 6 g / L sodium hydroxide, 8 g / L hydrogen peroxide, 3 g / L scouring agent A-88C, and 6 g / L oxygen bleaching stabilizer LS 66. The bath ratio was 1:8, the treatment temperature was 100℃, and the treatment time was 85 min.

[0091] (2) Silky With a fabric elongation of 3%, the fabric is treated with a 250 g / L sodium hydroxide solution at a temperature of 50°C and a machine speed of 20 m / min. After neutralization and washing, the mercerized cotton fabric is thoroughly washed, dried, and then mercerized a second time. The second mercerizing process is the same as the first mercerizing process.

[0092] (3) Staining The dyeing process was carried out using conventional reactive dyes.

[0093] (4) Bioenzyme treatment The pH of a solution containing 3 g / L polishing enzyme S-3500 and 18 g / L enzyme activity promoter was adjusted to 4.5 ± 0.2 using acetic acid. The fabric was then immersed in the solution and treated at 50 ± 0.5℃ for 55 min. The temperature was then raised to 80℃ to inactivate the polishing enzyme S-3500 for 10 min, followed by thorough washing with water.

[0094] (5) Softener treatment The softening process is achieved using a rolling and baking method.

[0095] Impregnating with softener solution → rolling → pre-drying (temperature 90℃, time 3.5min) → baking (temperature 170℃, time 4min) The softener treatment solution comprises hydroxyl silicone oil and waterborne polyurethane emulsion, with a mass ratio of hydroxyl silicone oil to waterborne polyurethane emulsion of 2:0.7, and a total softener concentration of 110 g / L in the treatment solution.

[0096] When the softener treatment solution is used, the ultrasonic frequency in the ultrasonic cleaner is 55kHz and the ultrasonic power is 300W.

[0097] The aqueous polyurethane emulsion is prepared by the following steps. A method for preparing an aqueous polyurethane emulsion involves heating and melting 30g of polycaprolactone diol (PCL), then cooling the mixture to 50°C and adding 20g of diisocyanate (the molar ratio of pentamethylene diisocyanate to 4,4'-dicyclohexylmethane diisocyanate is 4:6). The mixture is then heated to 60°C under reflux and reacted for 20 min. Next, 1.2g of dibutyltin dilaurate and 10g of acetone are added, and the mixture is heated to 70°C and reacted for another 25 min. Then, 6g of DMPA and 10g of acetone are added, and the mixture is heated to 85°C and reacted at this constant temperature for 15 min. Finally, 10g of methyl ethyl ketone oxime is added for end-capping reaction for 30 min. The mixture is then cooled to 50°C, and 0.5g of antioxidant and 4g of triethylamine are added. The mixture is neutralized for 30 min, and then DMPA containing 1g / L of defoamer is slowly added dropwise. After the water-in-oil phase inversion is completed, the remaining deionized water containing defoamer is quickly added to 8317 deionized water, and emulsification continues to obtain an aqueous polyurethane emulsion. In this embodiment, the enzyme activity promoter is one of PEG2000, Tween 80, sorbitol, and sodium lignosulfonate, preferably PEG2000.

[0098] In this embodiment, the hydroxyl silicone oil is one of monohydroxyl-terminated polydimethylsiloxane and dihydroxyl-terminated polydimethylsiloxane, preferably dihydroxyl-terminated polydimethylsiloxane; the polydiol is any one of polycaprolactone diol (PCL), polyether diol (PPG), polyether diol (PTMG), and polytetrahydrofuran diol (PTMEG), preferably polycaprolactone diol (PCL); the diisocyanate is hexamethylene diisocyanate or diphenylmethane diisocyanate. The waterborne polyurethane emulsion contains one or more of the following: ester, pentamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, preferably a mixture of pentamethylene diisocyanate and 4,4'-dicyclohexylmethane diisocyanate, with a preferred molar ratio of 4:6; the waterborne polyurethane has a weight-average molecular weight of 10,000 to 15,000, preferably 10,000; and the solid content of the waterborne polyurethane emulsion is 25%.

[0099] (6) Calendering The process is performed using conventional calendering.

[0100] The rest of the content is the same as in Example 1.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0102] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0103] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing an ultra-soft cotton fabric, characterized in that, Includes the following steps: (1) Preprocessing The desizing, scouring and bleaching are carried out by a one-bath one-step immersion method. The treatment solution consists of 4-6 g / L sodium hydroxide, 8-10 g / L hydrogen peroxide, 2-5 g / L scouring agent, and 4-6 g / L oxygen bleaching stabilizer. The bath ratio is 1:8, the treatment temperature is 90-100℃, and the treatment time is 85-95 min. (2) Silky Under the condition that the fabric elongation is 3-5%, it is treated with a sodium hydroxide solution of 200-250g / L at a temperature of 50-70℃ and a machine speed of 20-30m / min. After the mercerized cotton fabric is neutralized and washed, it is thoroughly washed again, dried, and then mercerized a second time. The second mercerizing process is the same as the first mercerizing process. (3) Staining Dyeing was performed using conventional reactive dye dyeing processes; (4) Bioenzyme treatment The pH of a solution containing 1-3 g / L polishing enzyme and 10-20 g / L enzyme activity promoter was adjusted to 4.5±0.2 using acetic acid. The fabric was then immersed in the solution and treated at 50±0.5℃ for 40-60 min. The temperature was then raised to 80℃ to inactivate the polishing enzyme S-3500 for 10 min. The fabric was then thoroughly washed with water and dried. (5) Softener treatment The softening process is achieved using a rolling and baking method; Impregnating with softener solution → rolling → pre-drying (temperature 80~100℃, time 3~5min) → baking (temperature 150~180℃, time 3~5min); The softener treatment solution comprises hydroxyl silicone oil and waterborne polyurethane emulsion, with a mass ratio of hydroxyl silicone oil to waterborne polyurethane emulsion of 2:0.5-1, and a total softener concentration of 80-120 g / L in the treatment solution. When the softener treatment solution is used, the ultrasonic frequency in the ultrasonic cleaner is 50-60kHz and the ultrasonic power is 200-300W. The aqueous polyurethane emulsion is prepared by the following steps: A method for preparing an aqueous polyurethane emulsion involves heating 30-50g of polydiol to melt, then cooling to 45-50℃ and adding 20-30g of diisocyanate. Under reflux, the temperature is raised to 50-60℃ and reacted for 20-30 minutes. Then, 0.5-1.5g of dibutyltin dilaurate and 10g of acetone are added, and the temperature is raised to 60-70℃ and the reaction continues for 15-30 minutes. Next, 5-10g of DMPA and 10-20g of acetone are added, and the temperature is raised to 80-90℃. After a constant temperature reaction for 10-20 minutes, 5-10g of methyl ethyl ketone oxime is added for end-capping reaction for 20-30 minutes. The temperature is then lowered to 45-50℃, and 0.3-1g of antioxidant and 3-5g of triethylamine are added. The neutralization reaction is carried out for 30 minutes. Finally, DMPA containing 1g / L of defoamer is slowly added dropwise. After the water-in-oil phase inversion is completed, the remaining deionized water containing defoamer is quickly added to the 8317 deionized water, and emulsification is continued to obtain a waterborne polyurethane emulsion. (6) Calendering The process is performed using conventional calendering.

2. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The enzyme activity promoter is one of PEG2000, Tween 80, sorbitol, and sodium lignosulfonate.

3. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The hydroxyl silicone oil is one of monohydroxy-terminated polydimethylsiloxane or dihydroxy-terminated polydimethylsiloxane.

4. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The polydiol is any one of polycaprolactone diol (PCL), polyether diol (PPG), and polytetrahydrofuran diol (PTMEG).

5. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The diisocyanate is one or a mixture of several of hexamethylene diisocyanate, diphenylmethane diisocyanate, pentamethylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

6. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The waterborne polyurethane has a weight-average molecular weight of 10,000 to 15,000; the solid content of the waterborne polyurethane emulsion is 25%.

7. The method for preparing an ultra-soft cotton fabric according to claim 1, characterized in that: The ultrasonic cleaning machine includes an immersion tank (7), with an upper edge plate (2) on the top of the immersion tank (7). Support legs (3) are provided on all four sides of the outer wall of the upper edge plate (2). Side plates (9) are provided on all four sides of the immersion tank (7). A handle groove (4) is provided on one side of the side plate (9). Multiple ultrasonic generators (13) are provided at the bottom of the immersion tank (7) and arranged in an array with equal spacing. A power supply (14) is provided at the bottom of the ultrasonic generator (13). A support plate (15) is provided at the bottom of the power supply (14). A heating tube (6) is provided on one side inside the immersion tank (7). A bent step structure (5) is provided on the top of the heating tube (6) of the immersion tank (7).

8. The method for preparing an ultra-soft cotton fabric according to claim 7, characterized in that: The support leg (3) is provided with a shock-absorbing foot at the bottom. The shock-absorbing foot includes a base. A support column (12) is provided at the center of the top of the base. A shock-absorbing spring (11) is sleeved on the support column (12). A guide sleeve (10) is sleeved on the outer wall of the shock-absorbing spring (11). The guide sleeve (10) is associated with the support column (12). An observation window is opened on the outer wall of the guide sleeve (10).

9. The method for preparing an ultra-soft cotton fabric according to claim 7, characterized in that: A control panel (1) is installed on the upper edge plate (2), and the control panel (1) is provided with control buttons.

10. The method for preparing an ultra-soft cotton fabric according to claim 7, characterized in that: The outer wall of the side plate (9) and the bottom of the immersion tank (7) are connected by a water supply pipe joint (8).

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