A paper diaper production method based on core layering pre-preparation and lamination

Abstract

The application discloses a paper diaper production method based on core layering prefabrication and lamination, and relates to the technical field of disposable sanitary products, and comprises the following steps: raw material preparation, absorption core layer carding, core swelling treatment, forming a storage area array, dividing the absorption core into nine functional subareas and performing differential SAP scattering, urine and feces subarea structure construction, core groove forming and edge sealing, lamination, hot air bonding integrated consolidation, three-layer flow guide groove forming, three-dimensional printing functional coating, self-adaptive temperature control layer lamination, micro-acid bacteriostatic surface layer lamination, overall paper diaper assembly, and finished product trimming. Through the multi-layer functional gradient core, swelling treatment and nine-subarea SAP precise scattering, the application realizes material differential distribution and enhances absorption in key areas. In combination with urine and feces subarea isolation, the application promotes rapid liquid diffusion, reduces back seepage and leakage, reduces the SAP usage amount while ensuring excellent absorption performance, and improves material utilization.

Description

Technical Field

[0001] This invention relates to the field of disposable hygiene products technology, specifically to a method for producing diapers based on core layer prefabrication and lamination. Background Technology

[0002] As a daily hygiene product, disposable diapers rely heavily on their absorbent core, which directly affects the product's absorption speed, rewetting capacity, leak-proof performance, and wearing comfort. Currently, the absorbent cores commonly found in the market fall into two main categories: one is the traditional core, which is formed by mixing wood pulp fibers with superabsorbent polymer (SAP) and then bonding them together using hot pressing or hot melt adhesive; the other is a composite core made by coating SAP particles with non-woven fabric.

[0003] However, in existing technologies, traditional cores typically distribute SAP (Symptomyces Aerosol) evenly across the entire core area, while actual urine excretion is mainly concentrated in the middle and rear of the core. This results in low utilization of polymer materials in the peripheral areas, leading to waste. Furthermore, the even distribution method makes it difficult to create an absorption gradient, leading to localized saturation, slow absorption, and high reabsorption. The core is also prone to clumping and tearing during use, affecting reliability. In addition, existing cores often use hot melt adhesives for interlayer bonding or thermoforming. Hot melt adhesives not only hinder liquid penetration and reduce core softness, but their chemicals also pose a risk of skin irritation. Thermoforming, on the other hand, thins and hardens the fluffy nonwoven fabric, disrupting the absorption channels between fibers, resulting in a stiff core and reduced breathability. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing diapers based on core layer prefabrication and lamination, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for producing diapers based on core layer prefabrication and lamination, comprising the following steps: raw material preparation, combing each layer of the absorbent core into a web, core expansion treatment, forming a storage area array, precise zoning and spreading of superabsorbent polymer (SAP), construction of urine and feces zoning structure, core groove forming and sealing, lamination, hot air bonding and integrated consolidation, three-layer guide channel forming, three-dimensional printed functional coating, adaptive temperature control layer lamination, micro-acid antibacterial surface layer lamination, overall diaper assembly (including waistband, Velcro, three-dimensional guard, and elastic band fixation), slitting and finished product finishing.

[0006] Specifically, such as Figure 1The absorbent core comprises, from top to bottom, a conductive layer, a diversion layer, an absorbent layer, a liquid storage layer, and a leak-proof bottom layer; each layer is prefabricated by carding into a web and then integrally bonded using hot air bonding. The diaper as a whole also includes a waistband, Velcro, elastic bands, 3D side guards, front waist tape, PE bottom film, hydrophilic nonwoven fabric, and water-repellent nonwoven fabric.

[0007] Preferably, the conductive layer is prepared by carding a first fiber into a web, the first fiber being selected from cotton fiber, viscose fiber, polyester fiber, or polypropylene fiber, with a basis weight of 15-25 g / m². 2 It is used to quickly catch liquid seeping from the surface layer.

[0008] The flow-guiding layer is prepared by mixing and carding 30-40% superabsorbent fiber (SAF) with a second fiber into a web. The SAF fiber is pretreated with plasma. The treatment process is as follows: at normal pressure, using air as the treatment gas, with a 10-20 second discharge followed by a 3-5 second pause, for a total treatment time of 45-50 seconds and a treatment power of 100-200W. The basis weight of the flow-guiding layer is 25-35 g / m³. 2 .

[0009] The absorbent layer is made by carding a web of 50-60% SAF fiber and a third fiber, and then subjecting it to a high-impurity roller randomization process, with a basis weight of 40-60 g / m². 2 The fineness of the third fiber is less than that of the second fiber.

[0010] The liquid storage layer has a sandwich structure consisting of an upper fiber web, a SAP particle layer, and a lower fiber web; the upper and lower fiber webs are made of hot-air nonwoven fabric or fiber cotton web with a basis weight of 20-80 g / m². 2 .

[0011] The leak-proof bottom layer is a PE breathable bottom film or a non-woven fabric composite material.

[0012] Preferably, the core expansion treatment involves bidirectional airflow expansion of the fluffy nonwoven fabric of the guide layer or absorbent layer, and the treatment device is sequentially arranged with a preheating zone, a heating zone, a leveling zone, and a setting zone along the conveyor belt direction. Preheating zone: Temperature 85-95℃, spray water mist evenly onto the nonwoven fabric surface, water volume 5-10g / m² 2 ; Heating zone: The surface of the nonwoven fabric is impacted by bidirectional high-pressure airflow at a pressure of 0.3-0.6 MPa. The airflow temperature is controlled by a dynamic temperature gradient, gradually increasing from 100℃ to 180℃ and then gradually decreasing from 180℃ to 110℃. Equilibrium zone: temperature 100-110℃, differential speed roller group is used to stretch the nonwoven fabric laterally, with a stretch ratio of 1.2-1.5 times; Shaping zone: Cool to room temperature.

[0013] After the expansion treatment, the thickness of the nonwoven fabric increases by 50%-80%, the porosity increases to over 85%, and the pore size expands from 50-100μm before treatment to 200-400μm.

[0014] Preferably, the array of storage zones is formed by using an ultrasonic perforation or embossing device to arrange at least two storage zones side-by-side in the transverse direction on the expanded nonwoven fabric. Each storage zone is perforated or embossed to form a recessed cavity for embedding SAP particles. The storage zone is 10-20 mm wide, 1-2 mm deep, and has a pore density of 20-50 pores / cm². 2 .

[0015] Preferred, such as Figure 2 SAP precise zoned application employs a multi-channel zoned application system to distribute SAP, dividing the absorber core into three sections along its length: front A, middle B, and rear C; and along its width: middle D and two side E sections, forming nine functional zones in a 3×3 pattern. The target SAP density values ​​for each zone are as follows: BD Zone (Central Core): 60–70 g / m 2 ; AD zone (front core): 40–45g / m 2 ; CD area (rear core): 35–40g / m 2 ; BE zone (both sides of the center): 15–20 g / m 2 ; AE / CE zone (front and back sides): 10–15 g / m 2 .

[0016] The multi-channel zoned spreading system consists of nine independently controlled spreading units, each equipped with an independent feeding valve and flow sensor. The feeding speed of each unit is adjusted in real time through a computer control system.

[0017] Preferred, such as Figure 3 The urine and feces partition structure is constructed, wherein the absorbent core includes a lower core and two urine cores respectively located on top of the lower core; the two urine cores are arranged along the length direction and are located on both sides of the lower core, and a feces channel is formed between the two urine cores, the width of the feces channel is not less than 2cm.

[0018] The thickness of the urine core is less than the thickness of the lower core, and the absorption speed of the urine core is greater than that of the lower core.

[0019] Preferably, the core groove forming and sealing specifically involves pre-setting 3-5 longitudinal grooves and 2-3 transverse grooves in the rear region of the absorbent core. The groove depth is 30%-50% of the core thickness, and the width is 5-10mm. The groove shape can be straight, wavy, or arc-shaped.

[0020] The groove distribution is fixed by overlapping and bonding two layers of non-woven fabric: the upper and lower non-woven fabrics are pre-pressed with indentations at corresponding positions, and the grooves are fixed and formed by overlapping and bonding the upper and lower non-woven fabrics.

[0021] The edge sealing method using non-woven fabric folding upwards is adopted: the edge covering the non-woven fabric is folded upwards to cover the two sides of the core, with a folding height of 5-15mm. The edge is simultaneously heat-pressed and shaped during the folding and sealing process.

[0022] Preferably, the composite layer and hot air bonding are integrated into a single solidification process. Specifically, the conductive layer, the flow guiding layer, the absorption layer, and the liquid storage layer are stacked and aligned in sequence and then fed into a hot air bonding machine for integrated solidification. The hot air bonding temperature is 150±50℃, and the hot air residence time is 10-30 seconds.

[0023] The fiber fineness of the conductive layer, flow guiding layer, absorbent layer, and liquid storage layer gradually decreases from top to bottom, forming a density gradient in the Z-direction (X-direction: the length direction of the diaper; Y-direction: the width direction of the diaper; Z-direction: the thickness direction of the diaper). This density gradient is integrated and stabilized through hydrogen bonds between fibers, without the need for adhesives or synthetic fibers.

[0024] Preferably, the three-layer guide channel forming is as follows: the first layer is an embossed guide channel: a heated embossing roller is used to press out concave and convex patterns on the surface of the core, the temperature of the embossing roller is 100-130℃, and the patterns are dotted, line-shaped or grid-shaped. The second layer is a grooved flow channel: a groove formed by overlapping and bonding two layers of non-woven fabric is used as a secondary flow channel; The third layer is an edge sealing and flow guiding structure: the non-woven fabric is folded upwards to form an edge guiding structure, which guides the liquid to concentrate in the middle and rear of the core.

[0025] Preferably, the 3D printing functional coating is performed using a piezoelectric inkjet printhead assembly or a multi-axis 3D printing robot at the following process nodes: A flow guiding pattern is printed on the conductive layer, wherein the flow guiding pattern is a mesh, dot, or radial lines; Print functional gradient SAP absorption layer patterns in the absorption layer; SAP enhanced absorption zone patterns are printed in the reservoir layer. The patterns can be stripes, islands, or rings. Microcapsule layers containing plant extracts, antibacterial ingredients, or pH indicators are printed on the surface of the core.

[0026] Preferably, the adaptive temperature control layer composite consists of a thermally conductive fiber layer placed between the absorbent core layer and the waterproof membrane. The waterproof membrane has multiple breathable pores with a pore size of 0.5-1.5 mm and a pore density of 50-100 pores / cm³. 2 A thermo-deformable polymer film is bonded to the inside of the waterproof membrane.

[0027] The thermodeformable polymer film shrinks when the temperature is above the phase transition temperature, with a shrinkage rate of ≥30%, to reduce the area of ​​the waterproof membrane's pores that are blocked; and expands when the temperature is below the phase transition temperature, with an expansion rate of ≥20%, to increase the area of ​​the waterproof membrane's pores that are blocked.

[0028] Preferably, the slightly acidic antibacterial surface layer composite uses slightly acidic antibacterial and weakly hydrophilic ES fiber as the surface layer material or the coating material of the absorbent core. The fiber is a PE / PET core-sheath structure fiber with a fineness of 1.5D-2.5D, forming a slightly acidic environment with a pH value of 5.0-6.0 at the contact surface.

[0029] The slightly acidic, antibacterial, and weakly hydrophilic ES fibers are spun in pure or blended form to form a surface nonwoven fabric with a basis weight of 18-25 g / m². 2 In the core coating layer, slightly acidic antibacterial and weakly hydrophilic ES fibers are mixed with non-antibacterial fibers at a mass ratio of 30:70 to 50:50 to form an antibacterial coating layer.

[0030] Preferred, such as Figure 4 After completing the core preparation, the entire diaper is assembled, which includes the following sub-steps: (1) Prepare a leak-proof layer and a three-dimensional protective enclosure.

[0031] The anti-leakage permeability layer is made of a composite of anti-backflow hydrophilic nonwoven fabric and anti-backflow water-repellent nonwoven fabric. The anti-backflow hydrophilic nonwoven fabric is positioned on the side furthest from the human body than the anti-backflow water-repellent nonwoven fabric. The anti-backflow hydrophilic nonwoven fabric is produced by adding a hydrophilic agent during the production process of fiber-type nonwoven fabric, which allows liquid to be quickly conducted to the absorbent core.

[0032] Elastic rubber bands are fixed to a hydrophilic anti-leakage nonwoven fabric using rubber band adhesive. The nonwoven fabric is then folded and wrapped around the elastic rubber bands to form a three-dimensional protective barrier. The elastic rubber bands are made of natural or synthetic rubber filaments. The three-dimensional barrier is supported and erected by the tension of the elastic rubber bands, thus preventing urine leakage.

[0033] The three-dimensional protective enclosure is fixed in one or a combination of the following two ways: the two sides of the three-dimensional protective enclosure are fixed to the surface non-woven fabric with hot melt adhesive; the two sides of the three-dimensional protective enclosure are fixed to the PE bottom film with hot melt adhesive.

[0034] (2) Prepare the waist belt and the magic buckle.

[0035] The waistband is made of elastic non-woven fabric and is fixed to both sides of the back waist of the diaper through a folding and squeezing process. There are two Velcro fasteners, one attached to the side closer to the body and the other attached to the side further away from the body; the Velcro fasteners are fixed to the side of the front waistband of the diaper closer to the body with hot melt adhesive and are fixed to both sides of the waistband through a folding and squeezing process.

[0036] (3) Overall composite.

[0037] The prepared core is fixed to the PE bottom film with hot melt adhesive; the diversion layer is placed between the surface hydrophilic nonwoven fabric and the absorbent core; the anti-leakage layer, diversion layer, absorbent core, bottom film, and front waistband are sequentially bonded together with hot melt adhesive; the inner surface layer is composed of hydrophilic nonwoven fabric and anti-leakage layer bonded together with hot melt adhesive to form a combination of water-repellent sides and hydrophilic middle; finally, the waistband, Velcro, elastic band, and other components are assembled according to the design position to form a T-shaped elastic diaper.

[0038] The hydrophilic nonwoven fabric, water-repellent nonwoven fabric, and diversion layer are at least one of hot-air polypropylene fiber nonwoven fabric or hot-pressed polypropylene fiber nonwoven fabric. The bottom film is a breathable PE film. The front waistband is located in the front waist area of ​​the diaper and is used to cooperate with the Velcro for fixation.

[0039] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes a multi-layered functional gradient structure design for the absorbent core, increasing fiber porosity and the embedding depth of superabsorbent polymer (SAP). A nine-zone precision distribution system divides the core into different functional areas based on the pattern of human urine excretion, achieving differentiated and gradient distribution of SAP. This concentrates the polymer material in key absorption areas, reducing the amount used in peripheral areas, significantly reducing the total amount of SAP while maintaining excellent absorption performance. Simultaneously, a urine-feces zone physical isolation structure and a three-layer flow channel composite system are introduced to effectively promote rapid liquid diffusion and flow, reducing the contact area between excrement and skin. Absorption speed, reabsorption, and leakage control are all superior to traditional technologies.

[0040] 2. This method abandons the traditional hot melt adhesive bonding method and adopts hot air bonding for integrated consolidation and Z-axis density gradient hydrogen bonding. This allows the core layers to be stably bonded without chemical adhesives, maintaining a fluffy and soft touch while avoiding chemical irritation to the skin. Simultaneously, the slightly acidic, antibacterial, and biocompatible ES fiber surface layer creates a long-lasting slightly acidic environment on the contact surface, effectively inhibiting bacterial growth and significantly reducing the incidence of diaper rash. The T-shaped elastic waistband structure, combined with adjustable Velcro and elastic band three-dimensional guards, allows for flexible adjustment of waist tightness and reliable side leakage prevention. The adaptive temperature control layer dynamically adjusts breathability according to the core temperature, alleviating stuffiness and significantly improving overall wearing comfort. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the layered structure of the absorber core in this invention; Figure 2 This is a schematic diagram of the 9-partition layout for SAP precise partitioning in this invention; Figure 3 This is a cross-sectional schematic diagram of the urine and feces partition structure in this invention; Figure 4 This is a schematic diagram of the unfolded overall diaper of the present invention. Detailed Implementation

[0042] 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.

[0043] Example 1: Refer to Figures 1-4 The following is a method for producing diapers based on core layer prefabrication and lamination: The method includes the following steps: Step 1: Raw material preparation.

[0044] 3D polyester fiber was selected as the first fiber; 2D viscose fiber as the second fiber; and 1.2D viscose fiber as the third fiber. SAF fiber (super absorbent fiber) pretreatment: atmospheric pressure plasma treatment, air atmosphere, discharge for 15 seconds and stop for 4 seconds, total treatment time 48 seconds, power 150W; SAP particle size 200μm, liquid absorption rate 35g / g.

[0045] Step 2: Comb the layers of the absorbent core into a network.

[0046] Conductive layer: 100% first fiber combed into a web, basis weight 20g / m 2 ; The flow guide layer is a blend of 35% SAF and 65% secondary fiber, carded into a web with a basis weight of 30 g / m². 2 ; Absorbent layer: 55% SAF and 45% third fiber mixed and carded into a web, then randomized by a high-impurity roller, with a basis weight of 50 g / m². 2 ; Liquid storage layer upper and lower fiber webs: hot-air nonwoven fabric, 30g / m² 2 .

[0047] Step 3: Core expansion treatment.

[0048] The nonwoven fabrics of the flow guiding layer and the absorption layer are sequentially passed through an expansion treatment device: preheating zone 90℃, water spray 8g / m²2 The heating zone features bidirectional airflow at a pressure of 0.45 MPa, with the temperature rising from 110℃ to 170℃ and then decreasing to 115℃; the equilibrium zone has a temperature of 105℃ and a transverse stretch ratio of 1.35; the setting zone involves cooling. The treated nonwoven fabric exhibits a 65% increase in thickness and an 88% porosity.

[0049] Step 4: Form an array of storage areas.

[0050] On the expanded nonwoven fabric, an ultrasonic embossing device is used to form a 15mm wide, 1.5mm deep, and 35 pores / cm² pattern. 2 The storage area has three longitudinal channels arranged side by side in the transverse direction.

[0051] Step 5: SAP Precise Partition Distribution.

[0052] SAP is spread using a 9-zone spreading system at the following density: BD zone 65g / m³ 2 AD zone 42g / m 2 CD area 38g / m 2 BE zone 18g / m 2 AE / CE zone 12g / m 2 The computer control system adjusts the feeding speed of each unit in real time, with a deviation of ≤±2%.

[0053] Step Six: Constructing the urine and feces partition structure.

[0054] The above-mentioned liquid storage layer (including SAP) is used as the lower core, and urine cores (made of absorbent material) are set on both sides of its top. A fecal channel with a width of 2.5cm is reserved between the two urine cores; the thickness of the urine core is 60% of the thickness of the lower core.

[0055] Step 7: Core groove forming and edge sealing.

[0056] Four longitudinal grooves (1.8 mm deep, 8 mm wide) and two transverse grooves (1.5 mm deep, 6 mm wide) are pre-made in the rear part of the core. Double layers of non-woven fabric are overlapped and bonded to fix the grooves. The non-woven fabric is folded upward to seal the edges, with a folding height of 10 mm, and then simultaneously hot-pressed to shape.

[0057] Step 8: Lamination and hot air bonding.

[0058] The conductive layer, flow guiding layer, absorption layer, liquid storage layer and urine core are stacked and aligned in sequence, and then sent into a hot air bonding oven at 155℃ for 20 seconds to achieve integrated solidification.

[0059] Step 9: Forming of the three-layer guide channel.

[0060] First layer: A grid-like flow guide pattern is pressed onto the core surface using a heated embossing roller (temperature 120℃); Second layer: The formed grooves are used as flow guide channels; Third layer: The edge sealing and folding structure serves as an edge guide.

[0061] Step 10: 3D printing.

[0062] A piezoelectric inkjet printhead is used to print radial guide lines on the conductive layer; a striped SAP gradient absorption pattern is printed on the absorption layer; and a microcapsule layer containing aloe vera extract is printed on the core surface.

[0063] Step 11: Adaptive temperature control layer lamination.

[0064] A thermally conductive fiber layer is placed between the absorbent core layer and the PE waterproof membrane; the waterproof membrane has an opening diameter of 1.0 mm and a pore density of 80 pores / cm². 2 Breathable pores; a thermo-deformable polymer film (phase change temperature 32℃) is laminated to the inside of the waterproof membrane.

[0065] Step 12: Apply a slightly acidic antibacterial surface layer.

[0066] The surface nonwoven fabric is made of slightly acidic, antibacterial, and weakly hydrophilic ES fiber (1.8D), with a basis weight of 20g / m². 2 The fiber is mixed with non-antimicrobial fiber in a ratio of 40:60 in the core coating layer to form an antimicrobial coating layer.

[0067] Step 13: Assemble the entire diaper.

[0068] First, prepare the anti-leakage permeability layer: overlap the anti-reverse seepage hydrophilic nonwoven fabric with the anti-reverse seepage water-repellent nonwoven fabric, with the hydrophilic side away from the human body; fix the elastic rubber band (synthetic rubber filament) to the hydrophilic nonwoven fabric with rubber band glue, fold and wrap to form a three-dimensional protective barrier; and fix it with the surface nonwoven fabric by hot melt adhesive.

[0069] Next, prepare the waist belt and Velcro: the waist belt is made of elastic non-woven fabric, folded and squeezed to fix it to both sides of the back waist; the two Velcro are glued to the sides closer to the body and away from the body respectively, and fixed to the front waist patch with hot melt adhesive.

[0070] Finally, the entire assembly is completed: the core is fixed to the PE bottom film with hot melt adhesive; the diversion layer is placed between the surface hydrophilic nonwoven fabric and the core; the anti-leakage permeability layer, diversion layer, core, bottom film, and front waist patch are sequentially laminated; the close-fitting surface layer is composed of hydrophilic nonwoven fabric and anti-leakage permeability layer bonded together with hot melt adhesive to form a combination of water-repellent sides and hydrophilic middle; finally, the waist belt, Velcro, and elastic band are assembled.

[0071] Step Fourteen: Slicing and Finishing.

[0072] The diapers on the continuous production line are cut into baby size L (approximately 450mm in length), folded, and packaged to obtain the finished product.

[0073] In this embodiment, compared with traditional diaper production methods, a multi-layer functional gradient core is adopted, combined with bidirectional airflow expansion treatment and material storage zone array, which significantly improves fiber porosity and SAP embedding depth; by precisely spreading SAP in 9 zones, the gradient and differentiated distribution of polymer materials is achieved, which greatly reduces the amount of SAP used while ensuring absorbency; the introduction of a urine and feces partition physical isolation structure and a three-layer guide channel composite system effectively promotes rapid liquid diffusion and guidance, reducing the contact area between excrement and skin; at the same time, the slightly acidic antibacterial ES fiber surface layer and the T-shaped waist elastic structure make the product effective in antibacterial and rash prevention, waistband fit, and side leakage prevention.

[0074] Example 2: Basically the same as Example 1, except that the SAP partition density is adjusted to 70g / m² in the BD zone. 2 AD zone 45g / m 2 CD area 40g / m 2 BE zone 20g / m 2 AE / CE zone 15g / m 2 The expansion treatment stretch ratio is 1.5; the hot air bonding temperature is 170℃ and the dwell time is 15 seconds; the mixing ratio of slightly acidic antibacterial ES fiber and non-antibacterial fiber is 50:50; the three-dimensional protective enclosure is fixed with the PE base film.

[0075] Example 3: It is basically the same as Example 1, except that: no adaptive temperature control layer is set, and only air pores are added on the basis of the slightly acidic antibacterial surface layer.

[0076] The performance test results are as follows: The diapers obtained in Example 1 were tested according to national standard GB / T 28004 and enterprise standards. The results are as follows:

[0077] The diaper prepared according to Embodiment 1 of this invention exhibits significantly faster absorption rates during both the first and second applications of urine compared to traditional uniformly distributed cores; rewetting and leakage are drastically reduced; core thickness is significantly thinner; average SAP usage is effectively reduced, achieving cost reduction and efficiency improvement; it also possesses excellent antibacterial properties, significantly reducing the incidence of diaper rash; and the waistband fit and three-dimensional leak-proof pass rate are superior to traditional technical solutions. These results demonstrate that the method of Embodiment 1 of this invention has comprehensive and outstanding advantages in terms of absorbency, material utilization, wearing comfort, and leak-proof reliability.

[0078] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing diapers based on core layer prefabrication and lamination, characterized in that, Includes the following steps: Raw material preparation, combing the absorbent core layers into a web, core expansion treatment, forming a storage area array, dividing the absorbent core into nine functional zones and applying highly absorbent resin in a differentiated manner, constructing the urine and feces partition structure, core groove forming and sealing, layering and lamination, hot air bonding and integrated consolidation, forming a three-layer guide channel, three-dimensional printing of functional coating, adaptive temperature control layer lamination, micro-acid antibacterial surface layer lamination, overall diaper assembly and slitting of finished products. The absorbent core consists of a conductive layer, a flow guiding layer, an absorbent layer, a liquid storage layer, and a leak-proof bottom layer, from top to bottom. The five layers are prefabricated by combing into a network and then bonded together using hot air bonding.

2. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The conductive layer has a basis weight of 15-25 g / m³. 2 The first fiber is combed into a web; the flow-guiding layer is composed of 30-40% superabsorbent fiber and a second fiber, which are then pretreated by plasma and combed into a web, with a basis weight of 25-35 g / m². 2 ; The absorbent layer is composed of 50-60% SAF fibers and third fibers, which are mixed, carded into a web, and then randomized, with a basis weight of 40-60 g / m². 2 The fineness of the third fiber is smaller than that of the second fiber; The liquid storage layer has a sandwich structure consisting of an upper fiber web, a middle SAP particle layer, and a lower fiber web, with a basis weight of 20-80 g / m³. 2 ; The leak-proof bottom layer is a PE breathable bottom film or a non-woven fabric composite material.

3. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The core expansion treatment is a bidirectional airflow expansion treatment of the fluffy nonwoven fabric of the flow guiding layer or absorption layer, which passes through the preheating zone, heating zone, equalization zone and shaping zone in sequence. The preheating zone has a temperature of 85-95℃ and is equipped with a device for spraying water mist onto the surface of the nonwoven fabric, with a spray volume of 5-10 g / m³. 2 ; The heating zone is equipped with a bidirectional high-pressure airflow with a pressure of 0.3-0.6 MPa. The airflow temperature is controlled as a dynamic temperature gradient, gradually increasing from 100°C to 180°C and then gradually decreasing from 180°C to 110°C. The temperature in the equalization zone is 100-110℃, and a differential speed roller group is set to stretch the nonwoven fabric laterally with a stretching ratio of 1.2-1.

5. The shaping area is cooled to room temperature.

4. The method for producing diapers based on core layer prefabrication and lamination as described in claim 1, characterized in that: The formation of the storage area array is achieved by using an ultrasonic perforation or embossing integrated device to set at least two storage areas side by side in the transverse direction on the expanded non-woven fabric. Each storage area is formed into a recessed cavity by perforation or embossing, and the cavity is used to embed SAP particles. The storage area is 10-20mm wide, 1-2mm deep, and has a pore density of 20-50 pores / cm³. 2 .

5. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The nine functional zones are formed by dividing the absorption core into front zone A, middle zone B, and rear zone C in the length direction, and into middle section zone D and two side zones E in the width direction, thus creating a 3×3 nine-zone system. The SAP density for each zone is set as follows: 60-70 g / m³ for the BD zone. 2 AD zone 40-45g / m 2 CD area 35-40g / m 2 BE zone 15-20g / m 2 AE / CE zone 10-15g / m 2 ; SAP spreading employs a multi-channel zone spreading system, which consists of nine independently controlled spreading units. Each unit is equipped with an independent discharge valve and flow sensor, and the discharge speed of each unit is adjusted in real time through a computer control system.

6. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: In the urine and feces partition structure, the absorbent core includes a lower core and two urine cores respectively located on top of the lower core; Two urine cores are arranged along the length direction, located on both sides of the lower core, and a fecal channel is formed between the two urine cores. The width of the fecal channel is not less than 2cm. The thickness of the urine core is less than the thickness of the lower core, and the absorption speed of the urine core is greater than that of the lower core.

7. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: Three to five longitudinal grooves and two to three transverse grooves are pre-formed in the rear part of the core. The groove depth is 30% to 50% of the core thickness and the width is 5 to 10 mm. The groove lines can be straight, wavy, or curved. The groove distribution is fixed by overlapping and bonding two layers of non-woven fabric. The upper and lower non-woven fabrics are pre-pressed with indentations at corresponding positions. The grooves are fixed and formed by overlapping and bonding the upper and lower non-woven fabrics. The edge sealing method of folding the non-woven fabric upward is adopted. The edge covering the non-woven fabric is folded upward to cover the two sides of the core. The folding height is 5-15mm. The edge is heat-pressed and shaped simultaneously during the folding and sealing process.

8. The method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The integrated solidification of the laminated composite and hot air bonding involves stacking and aligning the conductive layer, the flow guiding layer, the absorption layer, and the liquid storage layer in sequence, and then feeding them into a hot air bonding machine for integrated solidification. The hot air bonding temperature is 150±50℃, and the hot air residence time is 10-30 seconds. The fiber fineness of the conductive layer, flow guiding layer, absorption layer and liquid storage layer gradually decreases from top to bottom, forming a density gradient in the Z-direction. The density gradient is integrated through hydrogen bonds between fibers without the aid of adhesives or synthetic fibers.

9. A method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The three-layer flow guide groove forming includes: the first layer is an embossed flow guide groove, which uses a heated embossing roller to press dot-shaped, line-shaped or grid-shaped patterns on the core surface; the second layer is a grooved flow guide groove, which uses a groove formed by overlapping and bonding two layers of non-woven fabric as a secondary flow guide channel; the third layer is an edge sealing flow guide, which uses an edge sealing structure with non-woven fabric folded upward as an edge guiding structure. The three-dimensional printed functional coating uses a piezoelectric inkjet printhead or a multi-axis three-dimensional printing robot to print a mesh, dot or radial line guide pattern on the conductive layer, a functional gradient SAP absorption layer pattern on the absorption layer, a strip, island or ring SAP enhanced absorption area pattern on the reservoir layer, and a microcapsule layer containing plant extracts, antibacterial ingredients or pH indicators on the core surface. The adaptive temperature control layer composite consists of a thermally conductive fiber layer placed between the absorbent core layer and the waterproof membrane, with the waterproof membrane having pores of 0.5-1.5 mm in diameter and a pore density of 50-100 pores / cm². 2 The membrane has ventilation holes, and a thermotropic polymer film is adhered to the inner side of the waterproof membrane; the thermotropic polymer film has a shrinkage rate of ≥30% when the temperature is above the phase transition temperature and an expansion rate of ≥20% when the temperature is below the phase transition temperature. The slightly acidic antibacterial surface layer composite uses slightly acidic antibacterial and weakly hydrophilic ES fiber as the surface layer material or the coating material of the absorbent core. The fiber is a PE / PET core-sheath structure fiber with a fineness of 1.5D-2.5D and a contact surface pH value of 5.0-6.

0. The fiber is spun or blended to form a surface layer nonwoven fabric with a basis weight of 18-25 g / m². 2 In the core coating layer, the fiber is mixed with non-antimicrobial fiber at a mass ratio of 30:70 to 50:50 to form an antimicrobial coating layer.

10. A method for producing diapers based on core layer prefabrication and lamination according to claim 1, characterized in that: The assembly of the complete diaper includes the following sub-steps: Preparation of anti-leakage and permeability layer and three-dimensional protective barrier: anti-reverse seepage hydrophilic nonwoven fabric and anti-reverse seepage water-repellent nonwoven fabric are laminated, with the anti-reverse seepage hydrophilic nonwoven fabric located on the side away from the human body; elastic rubber bands are fixed to the anti-reverse seepage hydrophilic nonwoven fabric with rubber band adhesive, and then the anti-reverse seepage hydrophilic nonwoven fabric is folded and wrapped around the elastic rubber bands to form a three-dimensional protective barrier; the three-dimensional protective barrier is fixed to the surface nonwoven fabric on both sides with hot melt adhesive, or the three-dimensional protective barrier on both sides is fixed to the PE bottom film with hot melt adhesive. Preparation of waistband and Velcro: The waistband is formed by folding and extruding elastic non-woven fabric and fixed to both sides of the back waist of the diaper; two Velcros are set, one of which is glued to the side closer to the body and the other is glued to the side further away from the body; the Velcros are fixed to the side of the front waistband of the diaper closer to the body with hot melt adhesive and fixed to both sides of the waistband by folding and extruding. Overall composite: The core prepared above is fixed to the PE bottom film with hot melt adhesive; the diversion layer is placed between the surface hydrophilic nonwoven fabric and the absorbent core; the anti-leakage permeability layer, diversion layer, absorbent core, bottom film, and front waist tape are sequentially composited with hot melt adhesive; the surface layer that touches the body is composited with the hydrophilic nonwoven fabric and the anti-leakage permeability layer with hot melt adhesive to form a structure with water-repellent sides and a hydrophilic middle; finally, the waistband, Velcro, and elastic band are assembled according to the design position to form a T-shaped elastic diaper.

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