Process for the production of semi-debonded, creamed, calendered pure cotton nonwoven fabric

Abstract

This invention relates to the field of nonwoven fabric production technology, specifically disclosing a method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric, comprising the following steps: 1) First, the fiber web is prepared and physically reinforced through a carding and hydroentangling process to form a pure cotton greige fabric; 2) Then, the pure cotton greige fabric is semi-degreased through a sizing and bleaching process; 3) Cream is added to the semi-degreased pure cotton hydroentangled fabric roll, followed by calendering and drying to obtain the fabric roll; 4) The fabric surface is inspected for defects using a fabric inspection machine, and the qualified fabric rolls are slit and packaged according to production requirements using a slitting machine. The method provided by this invention uses mild chemical and heat treatment methods to partially remove natural oils (cotton wax), pectin, and other byproducts from the surface of cotton fibers, rather than completely removing them, thereby significantly improving the hydrophilicity, whiteness, and compatibility with subsequent cream components while retaining the natural soft touch of cotton fibers.

Description

Technical Field

[0001] This invention relates to the field of nonwoven fabric production technology, specifically to a method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabrics. Background Technology

[0002] Current pure cotton nonwoven fabric production faces numerous challenges: Excessive retention of surface oils (cotton wax, pectin) in natural cotton fibers hinders the material's hydrophilicity and finishing uniformity; over-degreasing easily leads to fiber stiffness and loss of natural softness. Simultaneously, traditional products have limited functionality, lacking high-value-added characteristics such as skincare and nourishment, and have a relatively rough surface with a less refined feel. While conventional calendering can improve surface smoothness, it often sacrifices fluffiness and softness. Furthermore, existing degreasing, functional finishing, and surface treatment are mostly separate, independent processes, resulting in long workflows, high energy consumption, and potential fiber damage, affecting the consistency of the finished product. Therefore, the industry urgently needs an integrated production method for pure cotton nonwoven fabrics that can moderately remove interfering oils from cotton fibers while preserving their natural softness, providing a lasting creamy nourishing effect, and achieving a smooth surface and delicate feel. This would enhance product added value and meet the high-end market's demand for natural, soft, and functional nonwoven fabrics. This invention addresses the aforementioned problems by proposing an innovative method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned shortcomings and provide a method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabrics. Through gentle chemical and heat treatment methods, the natural oils (cotton wax), pectin, and other byproducts on the surface of cotton fibers are partially removed, rather than completely removed. This significantly improves the hydrophilicity, whiteness, and compatibility with cream ingredients while retaining the natural soft touch of cotton fibers.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric, comprising the following steps: 1) First, the fiber web is prepared and physically reinforced through cleaning and hydroentangling processes to form a pure cotton fabric; 2) The pure cotton fabric is then subjected to a semi-degreasing treatment through a boiling and bleaching process; 3) The semi-degreased pure cotton spunlace fabric roll is pre-dried, then cream is added, and the roll is calendered and dried to obtain the fabric roll. 4) Then, the fabric surface is inspected for defects by the fabric inspection machine. The qualified fabric rolls are cut and packaged by the slitting machine according to the production requirements.

[0005] Preferably, in step 2), the spunlace pure cotton fabric is placed in a rinsing pot, and the weight of each roll entering the rinsing pot is controlled to be approximately 1850 kg. The rolls are then rinsed in the rinsing pot under the influence of chemicals. The specific process is as follows: 21) Pretreatment: Put the greige fabric into the scouring pot, stabilize the pressure inside the pot at 4.5 bar, add 70 kg of T300 pretreatment agent, and raise the working solution temperature to 60°C in the circulation system and maintain the temperature for 20 minutes. 22) Buffering treatment: Add 100 kg of SP buffer, stabilize the pressure inside the pot at 4.5 bar, raise the temperature of the system to 70°C at a uniform rate, and keep it at this temperature for 30 minutes. 23) Boiling and bleaching main reaction: Inject 250kg of hydrogen peroxide, stabilize the pressure inside the pot at 4.5bar, and precisely raise the temperature to 105℃ through a program, and maintain the reaction at this temperature and corresponding pressure for 70 minutes; this is the main reaction stage, the purpose of which is to completely remove pigments and residual impurities, and ensure that the whiteness of the fabric is greater than or equal to the index of 80 whiteness value.

[0006] 24) Neutralization and washing: Add 13kg of aqueous citric acid to neutralize the system to the final pH value of the process; then perform a total of four countercurrent washings, which take about 120 minutes in total, to obtain a pure cotton spunlace fabric roll.

[0007] Preferably, in step 2), the boiled and bleached pure cotton spunlace fabric roll is vacuum dehydrated in a production environment with a relative humidity of 55%-68%, with the dehydration fan operating at a negative pressure of 6-8 bar and a dehydration time of 30-40 minutes, so that its moisture content is maintained within the range of 40-50%.

[0008] Preferably, in step 3), the pure cotton spunlace fabric roll is processed sequentially after dehydration through an unwinding machine, a fabric storage rack, a rewinding mill, a liquid feed trough, a rolling mill, a drying drum dryer, a circular screen dryer, and a winding machine, and the pure cotton spunlace fabric roll undergoes cream addition in the liquid feed trough.

[0009] Preferably, the rolling mill roll pressure is set to 2.5-3 bar, and the moisture content of the fabric after rolling is controlled at 30-40%; the rolling mill pressure is set to 3-3.5 bar, the emulsion ratio is 5.3%, and the left and right pressures of the rolling mill rubber rollers are adjusted so that the deviation is less than 0.1 bar.

[0010] Preferably, the level of the cream in the liquid tank is maintained between 10-15cm, the length of the fabric immersed in the cream is between 20-30cm, and the liquid content of the spunlace fabric after passing through the liquid tank is controlled at 48-50% after rolling.

[0011] Preferably, the drum dryer is arranged in a 5-drum configuration for a total of 10 drums, with a drum surface temperature of 120°C; the circular mesh dryer uses a four-circular mesh configuration connected in series, with a circular mesh temperature of 110°C and a fan speed and frequency of 35 Hz; and the winding machine uses a pressure-driven passive winding mechanism.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention first optimizes the performance of pure cotton spunlace nonwoven fabric by semi-degreasing, so that it has excellent hydrophilicity and liquid absorption. When used in hygiene products, it can absorb moisture and keep dry, and it is not easy to backflow. It has natural properties, keeps consumers dry, improves user experience, and maintains a natural soft feel. In particular, compared with full degreasing, the residual cotton wax plays a natural soft and lubricating role, making the finished product more comfortable and skin-friendly, without dryness or roughness.

[0013] Furthermore, the gentle processing method minimizes damage to cotton fibers, preserving their natural strength and toughness, which is beneficial for improving the dry / wet strength of nonwoven fabrics. Compared to a full degreasing process, it saves on chemicals and energy while still achieving performance that meets the requirements of most applications, offering excellent cost-effectiveness.

[0014] (2) This invention forms a functional composite film on the fiber surface by adding a cream. The cream itself is a type of glycerin, which has moisturizing, softening, and drying effects. Through its lubricating components, it significantly reduces the coefficient of friction between fibers and between the fabric surface and the skin, thereby providing an immediate, smooth, skin-friendly soft touch. At the same time, the hydrophobic components in the cream construct low surface energy regions on the fiber surface, giving the fabric a moderate and controllable water repellency. This water repellency not only delays the instantaneous spread and penetration of the liquid, but also inhibits the lateral diffusion of the liquid on the fabric surface, reducing the diffusion area and increasing the liquid utilization rate. The combined effect of softening and water repellency reduces the surface moisture remaining on the fabric surface after contact with liquid, giving the product a dry and comfortable feel. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a flow chart of the semi-defatted boiling and bleaching process of the present invention; Figure 3 This is a flow chart of the integrated drying, impregnation, and calendering process of the present invention. Detailed Implementation

[0016] The technical solutions 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 a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. 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.

[0017] Example like Figure 1 The process flow of the production method for semi-degreased, creamed, and calendered pure cotton nonwoven fabric provided by this invention is as follows: carding - spunlace - scouring and bleaching (semi-degreased) - pre-drying - drying (adding cream) - calendering - winding into fabric - fabric inspection - slitting - packaging. This production method completely covers the entire process of semi-degreased + creamed + calendered pure cotton spunlace nonwoven fabric from fiber to finished product, and is an integrated and continuous production line design.

[0018] In practical applications, the fiber web is first prepared and physically reinforced through carding and hydroentangling to form a basic fabric. Then, the basic fabric undergoes a semi-degreasing process during sizing and bleaching. This crucial semi-degreasing process removes impurities, enhances hydrophilicity, and retains a certain degree of water repellency, preserving the natural softness of the cotton fibers. Following this, a pre-drying process is performed before creaming. The cream is applied to the fibers through a liquid tank, increasing the product's softness while also providing water repellency. After creaming, the fabric roll is dried and then calendered to improve its appearance and feel, increase its density, and enhance its luster, resulting in a high-quality fabric with a firm texture and excellent luster. The calendered fabric is then wound into rolls by a winding machine, and a fabric inspection machine is used to check for defects, ensuring the product meets quality standards. Qualified rolls are then slit and packaged according to customer requirements by a slitting machine. This series of processes ensures strict control over the specifications and quality of the finished product.

[0019] Boiling and bleaching semi-degreasing process: The boiling and bleaching process is the core process for achieving "semi-degreasing". Through gentle chemical and heat treatment methods, the natural oils (cotton wax), pectin and other byproducts on the surface of cotton fibers are partially removed, rather than completely removed. This significantly improves the hydrophilicity, whiteness and compatibility with subsequent cream ingredients while retaining the natural soft touch of cotton fibers.

[0020] In practice, the pure cotton fabric that has undergone the hydroentangling process is first placed into a scouring and bleaching pot. Generally, the weight of each roll entering the scouring and bleaching pot is controlled at around 1850 kg. The rolls are then scouring and bleached under the presence of chemicals. The specific process is as follows: a. Pretreatment: Place the pure cotton fabric into a scouring pot, stabilize the pressure inside the pot at 4.5 bar, add 70 kg of T300 pretreatment agent for pretreatment, raise the temperature of the working solution to 60°C in the circulation system and maintain the temperature for 20 minutes to fully wet and swell the fibers, initially remove some symbiotic substances, and establish a uniform action basis for subsequent reactions.

[0021] b. Buffering treatment: Add 100 kg of SP buffer, stabilize the pressure inside the pot at 4.5 bar, heat the system uniformly to 70°C, and keep it at this temperature for 30 minutes.

[0022] The key to this step is to stabilize the pH value of the reaction environment, providing stable and controlled chemical conditions for the subsequent bleaching process and preventing damage to fiber strength.

[0023] c. Boiling and bleaching main reaction: Inject 250kg of hydrogen peroxide, stabilize the pressure inside the pot at 4.5bar, and precisely raise the temperature to 105℃ through a program, and maintain the reaction at this temperature and corresponding pressure for 70 minutes.

[0024] This step is the main reaction stage, and its purpose is to thoroughly remove pigments and residual impurities to ensure that the whiteness of the fabric is greater than or equal to the whiteness value of 80.

[0025] d. Neutralization and washing: Add 13kg of aqueous citric acid to neutralize the system to the final pH value of the process (adjusted according to customer technical specifications). Then perform a total of four countercurrent washes, approximately 120 minutes in total, to ensure thorough removal of chemical residues and decomposition products, leaving the fabric surface neutral and clean.

[0026] Finally, the boiled and bleached pure cotton spunlace fabric rolls are vacuum dehydrated in a production environment with a relative humidity of 55%-68%, with the dehydration fan operating at a negative pressure of 6-8 bar for 30-40 minutes, so that the moisture content is maintained within the range of 40-50%. The performance optimization of semi-degreased pure cotton spunlace nonwoven fabric by the following methods is as follows: The prepared nonwoven fabric has excellent hydrophilicity and liquid absorption: it can absorb water instantly and the liquid spreads quickly, which is a core requirement for products such as wet wipes and face masks.

[0027] The prepared nonwoven fabric retains a natural soft feel: compared with full degreasing, the residual cotton wax plays a natural softening and lubricating role, making the finished product more comfortable and skin-friendly to the touch, without dryness or roughness.

[0028] The prepared nonwoven fabric can maintain good fiber strength: the mild processing process causes little damage to the cotton fibers, retains the natural strength and toughness of the cotton fibers, and is conducive to improving the dry / wet strength of the nonwoven fabric.

[0029] The prepared nonwoven fabric improves whiteness and cleanliness compared to existing nonwoven fabrics: it removes most of the pigments and impurities, making the fabric surface whiter, purer, and of higher quality.

[0030] The prepared nonwoven fabric can reduce biological sensitivity: by removing some of the nutrients such as proteins, it reduces the basis for microbial growth, making the product safer.

[0031] The process of preparing nonwoven fabrics is highly adaptable: it achieves a perfect balance between hydrophilicity and processing performance, which can meet the requirements of high-speed hydroentangling production lines and the functional requirements of end products.

[0032] Cost-effectiveness: It saves more chemicals and energy than the full degreasing process, while still achieving performance that meets the requirements of most applications, making it cost-effective.

[0033] The drying and creaming process: After dehydration, the pure cotton spunlace fabric rolls are suspended on a self-designed production line with functional finishing capabilities for processing. Specific procedures (e.g.) Figure 2 (As shown): Unwinder - Fabric storage rack - Heavy rolling mill - Drying cylinder dryer (pre-drying) - With liquid tank (add cream) - Circular wire dryer (drying) - Rolling car - Rewinder; The rolling mill's roll pressure is set to 2.5-3 bar to control the fabric's moisture content within the 30-40% range after rolling. The liquid level in the emulsion tank needs precise control, maintaining the emulsion level between 10-15 cm, with the fabric immersed in the emulsion for 20-30 cm. The rolling mill pressure is set to 3-3.5 bar, with an emulsion content of 5.3%. After passing through the emulsion tank and undergoing rolling, the liquid retention rate of the spunlace fabric should be controlled within the 48-50% range. Adjust the left, center, and right pressures of the rolling mill's rubber rollers to ensure a deviation of less than 0.1 bar, guaranteeing a liquid retention rate deviation of less than 1% after rolling. The drum dryer uses a 10-drum arrangement of 5 drums per row, with a drum surface temperature of 120℃. The rotary screen dryer uses a four-drum series configuration, with a drum temperature of 110℃, a fan speed and frequency of 35 Hz, and a pressure-driven passive winding mechanism.

[0034] In addition, this process is a composite process. First, the moisture in the fabric roll is removed, and then the cream liquid is applied evenly and quantitatively to the fabric surface in a liquid tank.

[0035] The calendering process of this application involves the following steps: the fabric roll, after drying and creaming, enters the calendering machine and passes through the rollers under hot pressure. The fabric surface softens due to heat, and the wax and cream components on the fiber surface further fuse to form a smooth and uniform surface.

[0036] In practical applications, a three-roll hot rolling mill is used, which includes one hot steel roll and two elastic rolls.

[0037] Temperature: The surface temperature of the rolls is generally controlled between 100-110℃, and adjusted according to the fabric thickness and gloss requirements.

[0038] Pressure: The linear pressure of the rolls is usually in the range of 12 kgf / cm, and the pressure uniformity deviation does not exceed ±5%.

[0039] Production line speed: The speed of the production line is generally 20–50 m / min, which is smoothly connected with the drying process.

[0040] The purpose of calendering: Improve surface smoothness: Eliminate fine wrinkles and fiber fuzz on the fabric surface, making the fabric smoother and firmer.

[0041] Enhanced luster: Hot pressing makes the fiber surface reflect more evenly, presenting a soft or bright luster.

[0042] Improved feel: The fabric is more delicate and soft, feels comfortable to the touch, and drapes well.

[0043] Improve structural compactness: Appropriately increase the fabric density to enhance the mechanical properties and appearance stability of the nonwoven fabric.

[0044] Key points for quality control: The roller surface should be clean and free of stains to prevent defects; temperature and pressure should be dynamically adjusted according to the fabric weight and moisture content; the uniformity of gloss, smoothness and hand feel of the fabric after calendering should be checked regularly; process parameters should be recorded to ensure batch-to-batch stability.

[0045] After the calendering process is completed, the fabric rolls enter the winding, inspection, slitting and packaging processes, ultimately forming semi-degreased cream-calendered pure cotton nonwoven fabric products that meet the requirements.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A process for the production of semi-debonded, creamed, calendered pure cotton nonwoven fabric, characterized in that, Includes the following steps: 1) First, the fiber web is prepared and physically reinforced through cleaning and hydroentangling processes to form a pure cotton fabric; 2) The pure cotton fabric is then subjected to a semi-degreasing treatment through a boiling and bleaching process; 3) The semi-degreased pure cotton spunlace fabric roll is pre-dried, then cream is added, and the roll is calendered and dried to obtain the fabric roll. 4) Then, the fabric surface is inspected for defects by the fabric inspection machine. The qualified fabric rolls are cut and packaged by the slitting machine according to the production requirements.

2. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 1, characterized in that, In step 2), the spunlace pure cotton fabric is placed into a bleaching pot, and the weight of each roll entering the bleaching pot is controlled at 1850 kg. The rolls are then bleached under the presence of chemicals. The specific process is as follows: 21) Pretreatment: Put the greige fabric into the boiling and bleaching pot, the pressure inside the pot is 4.5 bar, add 70 kg of T300 pretreatment agent for pretreatment, and raise the temperature of the working solution to 60℃ in the circulation system and maintain the temperature for 20 minutes. 22) Buffering treatment: Add 100 kg of SP buffer, the pressure inside the pot is 4.5 bar, the system is heated to 70°C at a uniform rate, and kept at this temperature for 30 minutes. 23) Boiling and bleaching main reaction: Inject 250kg of hydrogen peroxide, the pressure inside the pot is 4.5bar, the temperature is precisely raised to 105℃ through program heating, and the reaction is kept at this temperature and corresponding pressure for 70 minutes. This is the main reaction stage, the purpose of which is to completely remove pigments and residual impurities and ensure that the whiteness of the fabric is greater than or equal to 80. 24) Neutralization and washing: Add 13 kg of aqueous citric acid to neutralize the system to the final pH value of the process; The fabric then undergoes four counter-current washes over a total of 120 minutes to produce a roll of pure cotton spunlace fabric.

3. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 2, characterized in that, In step 2), the boiled and bleached pure cotton spunlace fabric rolls are vacuum dehydrated in a production environment with a relative humidity of 55%-68%. The dehydration fan operates at a negative pressure of 6-8 bar and the dehydration time is 30-40 minutes, so that the moisture content is maintained within the range of 40-50%.

4. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 1, characterized in that, In step 3), the pure cotton spunlace fabric roll is processed sequentially after dehydration through an unwinding machine, a fabric storage rack, a re-rolling mill, a liquid feed trough, a rolling mill, a drying drum dryer, a circular screen dryer, and a winding machine. The pure cotton spunlace fabric roll undergoes cream addition in the liquid feed trough.

5. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 4, characterized in that, The rolling mill's roll pressure is set to 2.5-3 bar, and the fabric's moisture content is controlled at 30-40% after rolling. The rolling mill's pressure is set to 3-3.5 bar, the emulsion content is 5.3%, and the left and right pressures of the rolling mill's rubber rollers are adjusted so that the deviation is less than 0.1 bar.

6. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 4, characterized in that, The liquid level of the emulsion in the liquid tank is maintained between 10-15cm, the length of the fabric immersed in the emulsion is between 20-30cm, and the liquid retention rate of the spunlace fabric after passing through the liquid tank and being rolled is controlled at 48-50%.

7. The method for producing semi-degreased, creamed, and calendered pure cotton nonwoven fabric according to claim 4, characterized in that, The drum dryer is arranged in a 5-drum configuration for a total of 10 drums, with a drum surface temperature of 120℃; the circular mesh dryer uses a four-circular mesh connected in series configuration, with a circular mesh temperature of 110℃ and a fan speed and frequency of 35Hz; the winding machine uses a pressure passive winding method.

Images