Method for producing low-friction cotton-soft wipes and cotton-soft wipes

Abstract

The application discloses a preparation method of low-friction cotton soft wipes and the cotton soft wipes and belongs to the technical field of low-friction cotton soft wipe preparation. In the application, cashew phenol glycidyl ether and N,N-dimethylethanolamine are used to synthesize a tertiary amine ether intermediate, then the tertiary amine ether intermediate is reacted with 1,3-propanesulfonic acid lactone to obtain an amphiphilic structure modifier, and the stable emulsion is prepared through reverse phase emulsification, high-speed homogenization and high-pressure microjet; the emulsion is matched into a foam finishing liquid, the foam finishing process is used for coating on a spunlace full-cotton substrate, and the finished product is prepared through liquid padding, heat setting, pre-drying and balance moisture regain. The cotton soft wipe prepared by the application has low friction coefficient, is skin-friendly and smooth, has no silicon spots and residue problems, meanwhile, the high water absorption and structural strength are maintained, the process is stable and controllable, is suitable for industrial production, and effectively solves the defects of traditional auxiliaries, such as easy falling, demulsification, oil floating and fiber damage.

Description

Technical Field

[0001] This invention relates to the field of low-friction cotton soft towel preparation, and particularly to a method for preparing a low-friction cotton soft towel and the cotton soft towel itself. Background Technology

[0002] With the improvement of modern living standards and the popularization of health concepts, the application scenarios of disposable cleaning products are becoming increasingly widespread. Cotton wipes, as a disposable non-woven product that can be used both wet and dry, and is soft and skin-friendly, have gradually replaced traditional towels and cotton pads due to their hygienic, convenient, and lint-free characteristics. They are widely used in personal care, infant care, and household cleaning, becoming an indispensable practical item in modern daily life. The core advantage of cotton wipes lies in the skin-friendly nature of their pure cotton material, making them suitable for the needs of sensitive skin, infants, and other special groups. In recent years, consumers have continuously increased their demands for the user experience of cotton wipes, and low-friction characteristics have gradually become an important direction for enhancing product competitiveness. By functionally modifying the cotton wipe base material to reduce the surface friction coefficient, skin-friendly comfort can be further improved, reducing skin friction irritation. Currently, the research and development of functional cotton wipes has become a mainstream trend in the industry. Developing low-friction cotton wipes by integrating textile finishing and organic synthesis technologies can better meet consumers' needs for high-quality cleaning products, aligning with the concept of a green and comfortable lifestyle, and possessing broad market prospects.

[0003] Existing methods for preparing low-friction cotton towels have many substantial drawbacks. Some methods use chemical modifiers, which are prone to poor adhesion and easy detachment, and may also leave residues. Other methods use silicone oil-based additives, which are prone to demulsification, oil floating, and the formation of silicone spots, affecting the appearance and user experience. Some processes also damage the cotton fiber structure, leading to a decrease in water absorption and toughness, making it difficult to balance low friction with core performance. Furthermore, some processes are complex and demanding, which is not conducive to large-scale industrial production. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing a low-friction cotton towel and the cotton towel itself, which can effectively solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a low-friction cotton soft towel, the specific implementation steps of which are as follows: S1: A tertiary amine ether intermediate is synthesized by epoxy ring-opening reaction of cashew phenol glycidyl ether and N,N-dimethylethanolamine as raw materials under nitrogen atmosphere and at 70-80℃. The intermediate is then reacted with 1,3-propanesulfonic acid lactone at 55-65℃ to obtain a modifier. The modifier emulsion is prepared by reverse emulsification, high-speed homogenization and high-pressure microfluidic treatment. S2: Take the modifier emulsion, deionized water and foaming agent, mix them with magnetic stirring to prepare the foam finishing liquid, and then evenly coat the foam finishing liquid onto the surface of the spunlace cotton nonwoven fabric substrate after foaming, and then perform a liquid padding treatment. S3: Heat-set the substrate after rolling, and then pre-dry the substrate to obtain a low-friction cotton towel.

[0006] Preferably, the mass ratio of cashew phenol glycidyl ether and N,N-dimethylethanolamine added in step S1 is (3.29-4.02):1.

[0007] Preferably, the foaming agent is a compound of sodium dodecyl sulfate and cocamidopropyl betaine, with a mass ratio of 1:1 to 1:2.

[0008] Preferably, the mass ratio of cashew phenol glycidyl ether and N,N-dimethylethanolamine added in step S1 is (3.29-4.02):1.

[0009] Preferably, the mass ratio of the tertiary amine ether intermediate added in step S1 to 1,3-propanesulfonic acid lactone is 1:(0.39-0.45).

[0010] Preferably, the emulsifier selected in the reverse emulsification method in step S1 is a mixture of Span-80 and Tween-80, with a mass ratio of Span-80 to Tween-80 of (1.5-2.5):1, and the amount added is 3-5% of the mass of the modifier.

[0011] Preferably, the oil phase in the reverse emulsification method is liquid paraffin, and the volume ratio of the oil phase to the water phase is 1:1.5-1:2.5.

[0012] Preferably, in step S1, the homogenization pressure of the high-pressure microjet treatment is 60-100 MPa, the number of cycles is 2-5, and the nozzle diameter of the high-pressure microjet is 0.1-0.3 mm.

[0013] Preferably, the mass ratio of the modifier emulsion, deionized water and foaming agent added in step S2 is (25-35):(60-72):(2-5).

[0014] Preferably, in step S2, a foam finishing process is used to apply the modifier emulsion to the fiber substrate, and the foaming ratio is (4-6):1.

[0015] Preferably, the pre-drying temperature in step S3 is 110-130℃, the processing time is 1-5 min, and the pre-drying adopts hot air pre-drying method with a hot air velocity of 1-3 m / s.

[0016] Preferably, step S3, after heat setting, further includes equilibration and rehydration for 20 to 28 hours at a temperature of 20°C to 25°C and a relative humidity of 60% to 70%, with the substrate being turned over every 4 to 6 hours during the equilibration and rehydration process.

[0017] According to another aspect of the present invention, a cotton towel prepared by the above-described preparation method is provided.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. In this technical solution, cashew phenol glycidyl ether and N,N-dimethylethanolamine undergo an epoxy ring-opening reaction under a nitrogen atmosphere to generate a tertiary amine ether intermediate. This intermediate then undergoes a nucleophilic addition reaction with 1,3-propanesulfonic acid lactone to generate a modifier with an amphiphilic structure. One end of the modifier molecule is a long-chain alkyl group derived from cashew phenol, and the other end is a quaternary ammonium salt sulfonic acid group. The emulsifier molecules are directionally adsorbed at the oil-water interface to form a dense molecular film, which, together with the electrostatic repulsion of the modifier microdroplets, achieves stable dispersion of the emulsion system. The amphiphilic structure of the modifier molecules can form hydrophobic interactions and hydrogen bonds with the hydroxyl groups on the surface of cotton fibers, achieving directional adsorption and firm binding of the modifier on the cotton fiber surface. During the subsequent heat setting process, the modifier molecules undergo slight cross-linking to form a dense lubricating layer on the cotton fiber surface. The synthesis of the modifier is a directional reaction with no by-products generated, and the directional adsorption of the emulsifier leaves no free residue, avoiding safety hazards caused by modifier and auxiliary agent residues, and improving the safety and stability of the product.

[0019] 2. This technical solution uses a self-synthesized amphiphilic modifier to replace the silicone oil-based additives in existing technologies. The modifier emulsion, prepared by a reverse emulsification method, maintains long-term stability by leveraging the steric hindrance effect of the emulsifier interface layer and the electrostatic repulsion effect of the modifier microdroplets, thus preventing emulsion demulsification and oil drift during storage, transportation, and foam finishing. After high-speed homogenization and high-pressure microfluidic treatment, the dispersed phase of the modifier emulsion has a uniform particle size, allowing it to be uniformly applied to the surface of the spunlace cotton nonwoven fabric substrate during subsequent foam finishing without local aggregation. This structurally avoids the generation of appearance defects such as silicone spots, ensuring uniform product appearance and improving product appearance quality and user experience.

[0020] 3. In this technical solution, the dispersed microdroplets of the modifier emulsion can uniformly penetrate into the interior of the cotton fiber bundles. The long-chain alkyl groups of the modifier molecules insert between the cotton fiber molecules, moderately weakening the hydrogen bonding between cellulose molecules, increasing the slippage between fibers, and achieving the low-friction performance of the cotton towel. This process does not damage the basic structure of the cotton fibers. The cross-linking effect of the modifier molecules can enhance the bonding force between cotton fibers, compensating for the decrease in mechanical properties caused by the weakening of hydrogen bonds, thus balancing the softness and durability of the cotton towel and preventing lint shedding and damage during use. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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. Example 1

[0022] A method for preparing a low-friction cotton soft towel, the specific implementation steps of which are as follows: S1: 100g of cashew phenol glycidyl ether and 30.4g of N,N-dimethylethanolamine were reacted with an epoxy ring-opening reaction at 70℃ under a nitrogen atmosphere for 2h to synthesize a tertiary amine ether intermediate; 41.8g of 1,3-propanesulfonic acid lactone was then reacted at 55℃ for 1.5h to obtain a modifier; using a reverse emulsification method, 3.7g of emulsifier was prepared from Span-80 2.2g and Tween-80 1.5g, with the addition amount being 3% of the modifier mass; 40mL of liquid paraffin was used as the oil phase and 60mL of deionized water was used as the aqueous phase; the emulsion of the modifier was obtained by high-speed homogenization and high-pressure microfluidic treatment, with a homogenization pressure of 60 MPa, 2 cycles, and a nozzle diameter of 0.1mm.

[0023] S2: Take 25g of modifier emulsion, 60g of deionized water and 2g of foaming agent composed of 1g of sodium dodecyl sulfate and 1g of cocamidopropyl betaine, and convert the three into a ratio of 25:60:2; mix them with magnetic stirring to obtain a foam finishing liquid; after foaming the foam finishing liquid (foaming ratio 4:1), coat it evenly on the surface of 200g of spunlace cotton nonwoven fabric substrate, and then perform a liquid-pinning treatment (pinning rate 60%).

[0024] S3: The substrate after sizing is heat-set and then pre-dried with hot air at 110℃ for 1 minute and 1 m / s. After heat setting, it is equilibrated and rehydrated for 20 hours at 20℃ and 60% relative humidity. The substrate is turned over every 4 hours during the rehydration process to obtain a low-friction cotton towel. Example 2

[0025] A method for preparing a low-friction cotton soft towel, the specific implementation steps of which are as follows: S1: 100g of cashew phenol glycidyl ether and 27.4g of N,N-dimethylethanolamine were reacted with an epoxy ring-opening reaction at 75℃ under a nitrogen atmosphere for 3h to synthesize a tertiary amine ether intermediate; 43.7g of 1,3-propanesulfonic acid lactone was then reacted at 60℃ for 2h to obtain a modifier; using a reverse emulsification method, 5.3g of emulsifier was prepared from Span-80 3.5g and Tween-80 1.8g, with the addition amount being 4% of the modifier mass; 50mL of liquid paraffin was used as the oil phase and 100mL of deionized water was used as the aqueous phase; the emulsion of the modifier was obtained by high-speed homogenization and high-pressure microfluidic treatment, with a homogenization pressure of 80 MPa, 3 cycles, and a nozzle diameter of 0.2mm.

[0026] S2: Take 30g of modifier emulsion, 66g of deionized water and 3.5g of foaming agent prepared from 1.4g of sodium dodecyl sulfate and 2.1g of cocamidopropyl betaine, and convert the three into a ratio of 30:66:3.5; mix them with magnetic stirring to obtain a foam finishing liquid; after foaming the foam finishing liquid (foaming ratio 5:1), evenly coat it on the surface of 200g of spunlace cotton nonwoven fabric substrate, and then perform a liquid-pickling treatment.

[0027] S3: The substrate after sizing is heat-set and then pre-dried with hot air at 120℃ for 3 minutes at a speed of 2m / s. After heat setting, it is equilibrated and rehydrated for 24 hours at 22℃ and 65% relative humidity. The substrate is turned over every 5 hours during the rehydration process to obtain a low-friction cotton towel. Example 3

[0028] A method for preparing a low-friction cotton soft towel, the specific implementation steps of which are as follows: S1: 100g of cashew phenol glycidyl ether and 24.9g of N,N-dimethylethanolamine were reacted with an epoxy ring-opening reaction at 80℃ under a nitrogen atmosphere for 4h to synthesize a tertiary amine ether intermediate; 46.1g of 1,3-propanesulfonic acid lactone was then reacted at 65℃ for 3h to obtain a modifier; using a reverse emulsification method, 6.8g of emulsifier was added at 5% of the modifier mass, with 60mL of liquid paraffin as the oil phase and 150mL of deionized water as the aqueous phase; the emulsion was prepared by high-speed homogenization and high-pressure microfluidic treatment at a homogenization pressure of 100 MPa, 5 cycles, and a nozzle diameter of 0.3mm.

[0029] S2: Take 35g of modifier emulsion, 72g of deionized water and 5g of foaming agent, wherein the foaming agent is composed of 1.7g of sodium dodecyl sulfate and 3.3g of cocamidopropyl betaine in a mass ratio of 1:2, mix them with magnetic stirring to obtain foam finishing liquid; after foaming the foam finishing liquid (foaming ratio 6:1), it is evenly coated on the surface of 200g of spunlace cotton nonwoven fabric substrate and then subjected to liquid padding treatment.

[0030] S3: The substrate after sizing is heat-set and then pre-dried with hot air at 130℃ for 5 minutes at a speed of 3m / s. After heat setting, it is equilibrated and rehydrated for 28 hours at 25℃ and 70% relative humidity. The substrate is turned over every 6 hours during the rehydration process to obtain a low-friction cotton towel.

[0031] Comparative Example 1 In this comparative example, the addition of 1,3-propanesulfonic acid lactone in S1 was removed, and only the tertiary amine ether intermediate generated by the reaction of cashew phenol glycidyl ether and N,N-dimethylethanolamine was used as the modifier. The remaining steps were the same as in Example 3.

[0032] (1) Friction coefficient test Turn on the friction coefficient measuring instrument, connect the power supply, preheat for 10 minutes, adjust the instrument to normal working condition, set the test speed to 100mm / min and the test load to 200g, replace the medical silicone friction block and fix it firmly.

[0033] Use tweezers to remove the balanced 10cm×10cm sample and lay it flat on the instrument's testing platform. Use clamps to fix the sample around its edges to ensure that the sample is free of wrinkles and looseness, and to prevent the sample from sliding during the test. Gently place the medical silicone friction block in the center of the sample surface, ensuring that the friction block is completely in contact with the sample surface and is not suspended.

[0034] Start the instrument and, after it completes one friction test, record the static and dynamic friction coefficients of the sample. Test each sample at three different locations (center, upper left corner, and lower right corner), repeat the above operation, and record the test data each time. Following the steps described above, the friction coefficient of all samples in Examples 1-3 and Comparative Example 1 was tested in sequence. The data of each group of parallel samples were compiled and the average value was calculated.

[0035] (2) Water absorption test Turn on the constant temperature water bath, add an appropriate amount of deionized water, adjust the water temperature to 25℃, and keep the water temperature stable; at the same time, use an electronic balance to weigh the mass of the dried standard absorbent filter paper (record as m1) and make a record. Use tweezers to remove the equilibrated 10cm×10cm sample, weigh its dried mass using an electronic balance (recorded as m2), and record the data; Hold one end of the sample with tweezers and immerse the other end of the sample completely in 25°C deionized water in a constant temperature water bath. After soaking for 30 seconds, quickly remove the sample, hang it vertically for 1 minute, and drain the surface water. Place the drained sample on the weighed standard absorbent filter paper, gently press the sample with tweezers to absorb the residual water on the sample surface, and weigh the total mass of the filter paper and the sample again (recorded as m3).

[0036] Calculate the water absorption rate using the formula: Water absorption rate (%) = (m3-m1-m2) / m2×100%. Complete the water absorption test for all groups of samples in sequence and calculate the average value of each group of parallel samples.

[0037] Table 1: Performance Test Data of Low-Friction Cotton Soft Towels

[0038] As can be seen from the data in Table 1, the low-friction cotton towels prepared in Examples 1-3 all exhibited good and similar performance in terms of average static friction coefficient, average dynamic friction coefficient, and average water absorption rate. However, the performance indicators of Comparative Example 1 showed significant differences compared to the examples. This indicates that the low-friction cotton towels prepared in Examples 1-3 have significant advantages, while Comparative Example 1, due to changes in key steps, resulted in a decline in product performance.

[0039] The average static friction coefficient of the biomaterials in Examples 1-3 was between 0.25 and 0.28, and the average dynamic friction coefficient was between 0.20 and 0.22, indicating that the cotton towels prepared in these examples have a low coefficient of friction. This is attributed to the unique mechanism of action of the modifier emulsion in this technical solution. The modifier molecule has an amphiphilic structure, with a long-chain alkyl group derived from cashew phenol at one end and a quaternary ammonium salt sulfonic acid group at the other end. During the preparation process, the dispersed phase microdroplets of the modifier emulsion can uniformly penetrate into the interior of the cotton fiber bundles. The long-chain alkyl group of the modifier molecule inserts between the cotton fiber molecules, moderately weakening the hydrogen bonding between cellulose molecules and increasing the slippage between fibers, thereby achieving the low friction performance of the cotton towel. At the same time, the cross-linking effect of the modifier molecule can enhance the bonding force between cotton fibers, compensating for the decrease in mechanical properties caused by the weakening of hydrogen bonds. This allows the cotton towel to maintain a certain degree of structural stability while possessing low friction performance, avoiding problems such as lint shedding and damage during use.

[0040] Comparative Example 1 had an average static friction coefficient of 0.42 and an average dynamic friction coefficient of 0.35, significantly higher than that of the Example. This is because Comparative Example 1 omitted the addition of 1,3-propanesulfonate lactone in S1, using only the tertiary amine ether intermediate generated from the reaction of cashew phenol glycidyl ether and N,N-dimethylethanolamine as the modifier. Without the amphiphilic modifier generated by 1,3-propanesulfonate lactone, a structure that effectively weakens intermolecular hydrogen bonding and increases fiber slippage, as in the Example, could not be formed, resulting in a significantly increased friction coefficient.

[0041] The average water absorption rates of Examples 1-3 ranged from 297.8% to 301.9%, demonstrating good water absorption. This is likely because the modifier's directional adsorption and strong bonding to the cotton fiber surface, as well as the dense lubricating layer formed on the cotton fiber surface during subsequent heat setting, did not damage the cotton fiber's inherent structure or water absorption properties. Furthermore, appropriate modification treatment may have optimized the surface structure of the cotton fibers, making them more conducive to moisture absorption and retention.

[0042] The average water absorption rate of Comparative Example 1 was 267.9%, lower than that of the Example. Because the modifier structure in Comparative Example 1 differed from that in the Example, it lacked the optimizing effect of the amphiphilic modifier on the cotton fibers. This may have resulted in the surface structure of the cotton fibers being unfavorable for water absorption, or the modification treatment potentially disrupting the original water absorption channels of the cotton fibers to some extent, thus reducing the water absorption rate.

[0043] In summary, the technical solution of this invention, through specific modifier synthesis and preparation processes, enables low-friction cotton towels to maintain good water absorption while reducing the coefficient of friction. In contrast, the comparative example, due to changes in key steps, resulted in a significant decrease in product performance, further demonstrating the effectiveness and superiority of the technical solution of this invention.

[0044] In the description of this specification, the terms "preparation example," "example," "various examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that example or preparation example, which are included in at least one example or preparation example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same example or preparation example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more examples or preparation examples.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a low-friction cotton towel, characterized in that, The specific implementation steps are as follows: S1: Using cashew phenol glycidyl ether and N,N-dimethylethanolamine as raw materials, a tertiary amine ether intermediate is synthesized by epoxy ring-opening reaction at 70-80℃ for 2-4 hours under nitrogen atmosphere. Then, it is reacted with 1,3-propanesulfonic acid lactone at 55-65℃ for 1.5-3 hours to obtain a modifier. The modifier emulsion is prepared by reverse emulsification method, high-speed homogenization, and high-pressure microfluidic treatment. S2: Take the modifier emulsion, deionized water and foaming agent, mix them with magnetic stirring to prepare the foam finishing liquid, and then evenly coat the foam finishing liquid onto the surface of the spunlace cotton nonwoven fabric substrate after foaming, and then perform a liquid padding treatment. S3: Heat-set the substrate after rolling, and then pre-dry the substrate to obtain a low-friction cotton towel.

2. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, The mass ratio of cashew phenol glycidyl ether and N,N-dimethylethanolamine added in step S1 is (3.29-4.02):

1.

3. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, The mass ratio of the tertiary amine ether intermediate added in step S1 to 1,3-propanesulfonic acid lactone is 1:(0.39-0.45).

4. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, In step S1, the emulsifier selected for the reverse emulsification method is a mixture of Span-80 and Tween-80, with a mass ratio of Span-80 to Tween-80 of (1.5-2.5):1, and the amount added is 3-5% of the mass of the modifier.

5. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, In step S1, the homogenization pressure of the high-pressure microjets is 60-100 MPa, and the number of cycles is 2-5.

6. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, The mass ratio of the modifier emulsion, deionized water and foaming agent added in step S2 is (25-35):(60-72):(2-5).

7. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, In step S2, a foam finishing process is used to apply the modifier emulsion to the fiber substrate, with a foaming ratio of (4-6):

1.

8. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, The pre-drying temperature in step S3 is 110-130℃, and the processing time is 1-5 min.

9. The method for preparing a low-friction cotton towel according to claim 1, characterized in that, Step S3, after heat setting, also includes equilibration and rehydration for 20 to 28 hours at a temperature of 20°C to 25°C and a relative humidity of 60% to 70%.

10. A low-friction cotton towel prepared by the method according to any one of claims 1-9.

Images