C-shaped water-absorbing core body based on long fiber diversion and preparation method of C-shaped water-absorbing core body

Abstract

The invention relates to a C-shaped water-absorbing core body based on long fiber diversion and a preparation method thereof, the C-shaped water-absorbing core body comprises an upper diversion layer and a lower C-shaped composite layer, and the diversion layer is bonded with the C-shaped composite layer; the upper flow guide layer is made of long fiber hot air non-woven fabric and is made of long fibers with the fiber length of 20-50 cm; the C-shaped composite layer is of a C-shaped structure with a groove in the center, and the C-shaped structure is formed by folding the left side and the right side of a composite water absorption material upwards. The composite water absorbing material is of a layered structure formed by compositing toilet paper, fluffy non-woven fabric and compact non-woven fabric from top to bottom. The flow guide layer is located above the groove, and the width of the flow guide layer is larger than the width of the groove and smaller than the width of the C-shaped composite layer. Through the combination of the long-fiber hot air non-woven fabric and the C-shaped composite layer, the liquid infiltration speed is remarkably increased, and meanwhile, the reverse osmosis resistance is enhanced; the problem that an existing water absorption core is low in infiltration efficiency is solved, and the water absorption core is suitable for the field of sanitary products such as sanitary towels and paper diapers.

Description

Technical Field

[0001] This invention belongs to the field of disposable hygiene products technology, and particularly relates to a C-type absorbent core for absorbent products such as sanitary napkins and diapers, and its preparation method. Background Technology

[0002] In the field of disposable hygiene products, the performance of the absorbent core directly affects the user experience. Traditional absorbent cores typically use hot-air nonwoven fabric made of short fibers (e.g., 2-5 cm) as the upper guiding layer, combined with a lower composite structure to achieve the absorbency function. For example, Chinese patent CN220025408 U discloses a nonwoven absorbent core with a short-fiber hot-air nonwoven fabric upper layer and a middle fiber layer and a polymer absorbent particle layer lower layer. However, the short-fiber hot-air nonwoven fabric has a shorter fiber length and lower porosity between fibers, which makes it easier for liquid to be blocked during the penetration process, resulting in a slower penetration rate.

[0003] In addition, existing composite layer structures (such as multi-layer structures composed of toilet paper, fluffy nonwoven fabric and spunlace nonwoven fabric) are mostly planar designs, lacking three-dimensional flow channels, which further limits the rapid diffusion of liquids.

[0004] The following technical problems exist in the existing technology:

[0005] 1. Short fiber hot air nonwoven fabric has low porosity and slow liquid infiltration rate: The porosity formed by short fibers (2~5cm) during the hot air bonding process is low (usually 40~50%), and there are many bonding points between fibers, which leads to the obstruction of the liquid infiltration path and makes it difficult to meet the needs of rapid absorption.

[0006] 2. The composite layer structure lacks a three-dimensional flow guiding design, resulting in uneven liquid diffusion: Most existing composite layers are planar structures, and the liquid tends to concentrate in the central area of ​​the core under the action of gravity, resulting in insufficient absorption in the edge areas and insufficient anti-reverse osmosis performance.

[0007] 3. Insufficient synergy between multiple materials limits overall water absorption efficiency: Traditional absorbent cores lack effective structural connection between the upper guiding layer and the lower composite layer, resulting in resistance when liquid is transferred between layers, which easily leads to stratification and affects overall performance. Summary of the Invention

[0008] To overcome the technical problems existing in the prior art, the present invention provides a C-type absorbent core based on long fiber flow guidance and its preparation method. Through its unique structural design, it significantly improves the liquid infiltration rate and solves the problem of low infiltration efficiency of short fiber hot air nonwoven absorbent cores in the prior art.

[0009] The technical solution adopted in this invention is as follows:

[0010] A C-type absorbent core based on long fiber flow guidance, the C-type absorbent core comprising an upper flow guiding layer and a lower C-type composite layer, wherein the flow guiding layer and the C-type composite layer are bonded together;

[0011] The upper flow guiding layer is made of long fiber hot air nonwoven fabric, which is made of long fibers with a fiber length of 20~50cm;

[0012] The C-shaped composite layer is formed by folding the left and right sides of the composite absorbent material upwards to create a C-shaped structure with a central groove. The composite absorbent material is composed of toilet paper, fluffy nonwoven fabric, and dense nonwoven fabric layered from top to bottom. The fluffy nonwoven fabric contains uniformly distributed superabsorbent polymer. The dense nonwoven fabric is made of spunlace nonwoven fabric or spunbond nonwoven fabric, and its fiber pores are smaller than the particle size of the superabsorbent polymer.

[0013] The flow guiding layer is located above the trench, and the width of the flow guiding layer is greater than the width of the trench and less than the width of the C-type composite layer.

[0014] Long fibers of 20-50cm form a continuous three-dimensional porous structure during hot air bonding, with a porosity 30-50% higher than that of short fiber hot air nonwoven fabrics; liquid can quickly penetrate along the fiber axis, with a penetration rate more than 50% higher than that of existing technologies.

[0015] The C-groove structure forms a three-dimensional flow channel, allowing liquid to spread rapidly along the grooves under gravity and capillary action. Toilet paper, as the permeable layer, has excellent hydrophilicity and initial liquid absorption capacity, enabling it to quickly absorb liquid and transfer it to the lower layers. Fluffy non-woven fabric, as the absorbent layer, has high fluffiness to hold a large amount of liquid, increasing absorbency and preventing backflow. Dense non-woven fabric, as the support layer, provides structural stability and prevents core deformation. At the same time, the fiber pores of the dense non-woven fabric are smaller than the particle size of the superabsorbent polymer, thus preventing the superabsorbent polymer from leaking downwards.

[0016] Preferably, the long fiber is a bicomponent fiber, with the core layer being a high-melting-point resin (such as polypropylene, melting point 160~200℃) and the sheath being a low-melting-point resin (such as polyethylene, melting point 100~120℃) with a melting point 80~120℃.

[0017] The high-melting-point resin core of the bicomponent fiber provides structural support, while the low-melting-point resin in the sheath forms dot-like bonds during hot air bonding. The unbonded areas between fibers remain open, further increasing porosity and significantly reducing liquid permeation resistance.

[0018] Preferably, the porosity of the hot air nonwoven fabric is 60-80%.

[0019] Preferably, the basis weight of the toilet paper is 10~25g / m³. 2The basis weight of fluffy nonwoven fabric is 15~60g / m². 2 The basis weight of dense nonwoven fabric is 7~40 g / m². 2 The basis weight of hot-air nonwoven fabric is 15~70g / m². 2 .

[0020] Preferably, the long-fiber hot-air nonwoven fabric and the C-type composite layer are bonded together with hot melt adhesive.

[0021] The present invention also provides a method for preparing the above-mentioned C-type absorbent core, comprising the following steps:

[0022] (1) Preparation of long fiber hot air nonwoven fabric: long fibers of 20~50cm are bonded together to form nonwoven fabric;

[0023] (2) Preparation of C-type composite layer: toilet paper, fluffy non-woven fabric and spunlace non-woven fabric are laminated to make composite absorbent material, and then the left and right sides of the composite absorbent material are folded upward to form a C-type structure.

[0024] (3) Assemble the core: bond the long fiber hot air nonwoven fabric to the C-type composite layer.

[0025] The long-fiber hot-air nonwoven fabric used in this invention can be directly sourced from the market (e.g., purchased from Toray Industries, Inc.), or it can be prepared by referring to the long-fiber nonwoven fabric preparation process involved in Chinese Patent CN 119546808 A, Chinese Patent CN 102587041 A, etc., through the fiber treatment, web forming and hot-air bonding steps in the prior art.

[0026] As a preferred option, step (1) specifically involves:

[0027] (1-1) Raw material selection: long fibers of bicomponent fiber are selected, in which the core layer is a high melting point resin with a melting point of 160~200℃ and the sheath layer is a low melting point resin with a melting point of 80~120℃.

[0028] (1-2) Fiber pretreatment: The raw material is loosened by an opening machine. The front roller speed of the opening machine is 200~300 r / min, the rear roller speed is 600~800 r / min, the speed ratio is controlled at 2.5~3 times, and the roller spacing is 20~60 mm.

[0029] Opening can be performed using a double-roller opener. By using the speed difference between the two rollers and an appropriate spacing, long fibers are initially opened, reducing the presence of fiber clumps. The speed ratio is controlled at 2.5 to 3 times to enhance the opening shear force while reducing the risk of long fiber entanglement.

[0030] (1-3) Carding: The opened fibers are fed into a carding machine for carding treatment. The pre-carding saw tooth density is 80~100 teeth / cm, and the linear speed is 2~3m / s; the main carding needle density is 150~250 needles / cm.2 Linear velocity 3~4m / s, velocity ratio controlled at 1.2~1.5 times, wind pressure -300~-500Pa;

[0031] Pre-carding uses a toothed roller pre-carding machine. The purpose of pre-carding is to further open up the fiber bundles and make the fibers initially straight. Since long fibers of 20-50cm are prone to entanglement, reasonable pre-carding conditions control helps to reduce friction and entanglement between fibers. The main carding is equipped with dense card cloth and is combined with a negative pressure suction system. Reasonable main carding conditions control can make the fibers straighter and more evenly distributed. The dense card cloth can better control the direction of long fibers, while the negative pressure suction system can adsorb the fibers onto the screen and prevent fiber drift.

[0032] The speed ratio is controlled at 1.2 to 1.5 times (e.g., 2.5 m / s for pre-carding and 3 to 3.75 m / s for main carding) to ensure smooth fiber transfer and reduce orientation deviation.

[0033] The air pressure is controlled at -300~-500Pa, which can ensure that the fiber adheres to the mesh and does not fly away, and also ensure smooth transfer, making it especially suitable for flexible conveying of long fibers.

[0034] (1-4) Hot air bonding: The combed fibers are bonded in sections to form a non-woven fabric structure. The preheating zone temperature is 90~110℃ and the processing time is 20~30s; the melting zone temperature is 130~170℃ and the processing time is 40~60s; the cooling zone temperature is 50~70℃ and the processing time is 15~25s; the hot air velocity is 2.0~3.5m / s.

[0035] The purpose of preheating is to gradually raise the temperature of the fiber in preparation for subsequent melt bonding, and to avoid sudden high temperature that could damage the fiber structure.

[0036] The melting zone is key to fiber bonding, and the temperature needs to be properly controlled to melt the skin and form bonding points. Due to the long length of long fibers, the time required to allow hot air to penetrate the fiber layer needs to be properly controlled.

[0037] The cooling zone enables the molten skin to solidify rapidly, fixing the structure of the nonwoven fabric; the cooling temperature and time need to be properly controlled to ensure the dimensional stability of the nonwoven fabric.

[0038] The hot air adopts an "upward blowing and downward suction" airflow distribution, and the wind speed directly affects the penetration effect of the hot air and the uniformity of fiber bonding.

[0039] (1-5) Post-processing: The obtained nonwoven fabric is calendered and wound to obtain the finished nonwoven fabric. The roller temperature is 80~100℃, the pressure is 0.3~0.5MPa, the linear speed is 4~6m / s; the winding speed is 4~6m / s, and the tension is 50~80N.

[0040] Calendering can improve the surface smoothness and gloss of nonwoven fabrics, while further enhancing the adhesion between fibers. Stable winding parameter control can ensure that the nonwoven fabric does not produce wrinkles or stretching deformation during the winding process, thus ensuring the dimensional accuracy of the product.

[0041] By rationally controlling various parameters in the preparation process, this invention not only effectively solves the problem of entanglement of long fibers during processing, but also improves the uniformity of hot air bonding, thereby giving the prepared long fiber hot air nonwoven fabric a flow guiding advantage.

[0042] Preferably, in step (1-1), the core layer is polypropylene (PET) and the skin layer is polyethylene (EVA).

[0043] Preferably, step (2) specifically involves:

[0044] (2-1) Spray super absorbent polymer on the first side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0045] (2-2) Spray hot melt adhesive on one side of the spunlace nonwoven fabric, then cover the adhesive-sprayed side of the spunlace nonwoven fabric with the first side of the fluffy nonwoven fabric sprayed with superabsorbent polymer, and then perform a pressing treatment.

[0046] (2-3) Spray super absorbent polymer on the second side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0047] (2-4) Spray hot melt adhesive on one side of the toilet paper, then cover the adhesive side of the toilet paper with the second side of the fluffy non-woven fabric sprayed with super absorbent polymer resin, and then perform a pressing process to form a composite absorbent material.

[0048] (2-5) Transfer the composite absorbent material to the folding machine. The folding machine uses the spunlace nonwoven fabric as the bottom surface to fold the left and right sides of the composite absorbent material upwards to form a C-shaped composite layer with a groove in the middle.

[0049] Preferably, step (3) is as follows: hot melt adhesive is sprayed on one side of the hot air nonwoven fabric, the sprayed adhesive side of the hot air nonwoven fabric is covered on the grooved side of the C-shaped composite layer, and then the adhesive is pressed to obtain the C-shaped absorbent core.

[0050] The beneficial effects of this invention are as follows:

[0051] 1. This invention uses long-fiber hot-air nonwoven fabric for flow guidance, providing a high-porosity flow channel for the absorbent core, which greatly improves the liquid infiltration rate; the synergistic effect of the two-component fibers significantly reduces the liquid permeation resistance.

[0052] 2. The C-type composite layer of the present invention has a three-dimensional flow guiding effect, which facilitates the rapid diffusion of liquid. The multi-layer materials of the composite layer form a synergistic effect, which can not only quickly absorb liquid and transfer it to the lower layer, but also effectively prevent liquid backflow.

[0053] 3. The rapid flow guidance of the long-fiber hot air nonwoven fabric of this invention is combined with the three-dimensional diffusion of the C-type composite layer, which allows the liquid to quickly and completely penetrate to the bottom of the core; the synergistic effect of the multi-layer materials improves the anti-backflow performance of the core and effectively keeps the skin dry;

[0054] 4. The fiber pores of the dense nonwoven fabric of the present invention are smaller than the particle size of the superabsorbent polymer, so that the superabsorbent polymer in the fluffy nonwoven fabric will not leak downwards. Attached Figure Description

[0055] Figure 1 This is a cross-sectional view of the C-type absorbent core of the present invention;

[0056] Figure 2 This is a longitudinal top view of the C-type absorbent core of the present invention;

[0057] Figure 3 This is a cross-sectional view of the C-type composite layer of the present invention;

[0058] Figure 4 This is a cross-sectional view of the composite absorbent material of the present invention.

[0059] Illustration: 1-Flow guiding layer, 2-C-type composite layer, 3-Toilet paper, 4-Fluffy non-woven fabric, 5-Dense non-woven fabric, 6-Groove. Detailed Implementation

[0060] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0061] Example 1

[0062] Reference Figures 1-3 A C-type absorbent core based on long fiber flow guidance, the C-type absorbent core includes an upper flow guiding layer 1 and a lower C-type composite layer 2, the flow guiding layer 1 and the C-type composite layer 2 are bonded together;

[0063] The upper flow guiding layer 1 is made of long fiber hot air nonwoven fabric, which is made of long fibers with a fiber length of 30cm;

[0064] The C-shaped composite layer 2 is formed by folding the composite absorbent material upwards from both sides to create a C-shaped structure with a central groove 6; see reference. Figure 4The composite absorbent material is composed of toilet paper 3, fluffy nonwoven fabric 4 and spunlace nonwoven fabric 5 layered from top to bottom. The fluffy nonwoven fabric 4 is uniformly distributed with superabsorbent polymer. The fiber pores of the spunlace nonwoven fabric are smaller than the particle size of the superabsorbent polymer, which can prevent the superabsorbent polymer in the fluffy nonwoven fabric 4 from leaking downward.

[0065] The flow guiding layer 1 is located above the trench 6, and the width of the flow guiding layer 1 is greater than the width of the trench 6 and less than the width of the C-type composite layer 2.

[0066] A method for preparing a C-type absorbent core based on long fiber flow guidance includes the following steps:

[0067] (1) Preparation of long fiber hot air nonwoven fabric:

[0068] (1-1) Raw materials: bicomponent fibers of polypropylene (core layer) and polyethylene (skin layer), fiber length 30cm;

[0069] (1-2) Fiber pretreatment: the front roller speed of the opening machine is 250 r / min, the rear roller speed is 700 r / min, and the roller spacing is 30 mm;

[0070] (1-3) Combing: Pre-combing tooth density 90 teeth / cm, linear velocity 2.2m / s; main combing needle density 200 needles / cm², linear velocity 3.3m / s, air pressure -400Pa;

[0071] (1-4) Hot air bonding: Preheating zone temperature 100℃, processing time 25s; melting zone temperature 150℃, processing time 50s; cooling zone temperature 60℃, processing time 20s; hot air velocity 3.0m / s;

[0072] (1-5) Post-processing: Roll temperature 90℃, pressure 0.4MPa, linear speed 5m / s; winding speed 5m / s, tension 65N;

[0073] Performance: Porosity 80%, longitudinal tensile strength 3.0 N / 5 cm, transverse tensile strength 2.2 N / 5 cm.

[0074] (2) Preparation of C-type composite layer:

[0075] (2-1) Spray superabsorbent polymer on the first side of the fluffy nonwoven fabric (25g / m²) and vibrate to make the superabsorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0076] (2-2) Spray hot melt adhesive on one side of the spunlace nonwoven fabric (35g / m²), then cover the adhesive-sprayed side of the spunlace nonwoven fabric with the first side of the fluffy nonwoven fabric sprayed with superabsorbent polymer, and then perform a pressing treatment.

[0077] (2-3) Spray super absorbent polymer on the second side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0078] (2-4) Spray hot melt adhesive on one side of toilet paper (12g / m²), then cover the adhesive side of the toilet paper with the second side of the fluffy non-woven fabric sprayed with super absorbent polymer resin, and then perform a pressing process to form a composite absorbent material.

[0079] (2-5) Transfer the composite absorbent material to the folding machine. The folding machine uses the spunlace nonwoven fabric as the bottom surface to fold the left and right sides of the composite absorbent material upwards to form a C-shaped composite layer with a groove in the middle.

[0080] (3) Core assembly:

[0081] Hot melt adhesive is sprayed onto one side of a hot air nonwoven fabric (30g / m²), and the adhesive-sprayed side of the hot air nonwoven fabric is placed over the grooved side of the C-shaped composite layer. Then, the adhesive is pressed to obtain the C-shaped absorbent core.

[0082] Effect Experiment

[0083] According to the People's Republic of China National Standard GB / T28004-2011, the method for measuring leakage in diapers (pads, sheets), the C-type absorbent core of this embodiment was made into a baby diaper as a sample. The sample was placed on an inclined plate with an inclination of (30±2)°, with the usable side facing up. 100 mm was taken at both ends of the center point of the absorbent core of the sample as the test area. 50 ml of test solution was measured and allowed to flow freely to the surface of the sample and along the inclined plate. The experiment was repeated more than six times. The volume of test liquid flowing out from each sample was recorded. The average value was taken after multiple tests. No leakage occurred in the six tests on average.

[0084] According to the People's Republic of China National Standard GB / T28004-2011, the method for measuring rewetting in diapers (pads, sheets), a medium-sized baby diaper made from the C-type absorbent core of this embodiment was used as a sample. 60ml of test solution was allowed to flow freely to the surface of the center of the sample through a funnel. After 5 minutes, the same amount of test solution was injected again through the funnel. After 10 minutes, several layers of filter paper with a diameter of 100mm were placed on the surface of the sample, and a standard pressure block was pressed on the filter paper. After applying pressure for 1 minute, the standard pressure block was removed. This measurement method was repeated multiple times, and the average rewetting of the sample was finally measured to be 0.2g, which is lower than the national standard of 10g.

[0085] According to the People's Republic of China National Standard GB / T28004-2011 Method for Measuring Leakage in Diapers (Pads, Sheets), the C-type absorbent core of this embodiment was made into an adult diaper as a sample. The sample was laid flat on a horizontal platform, and 80 ml of test solution was measured using a separatory funnel and poured into the center of the sample at a uniform speed within 30 seconds. After 5 minutes, no liquid leakage was observed around the sample.

[0086] Infiltration test: When using the water-absorbing core of the present invention, 60ml of test solution flows freely through the funnel to the surface of the center of the sample. After multiple tests, on average, the test solution on the surface layer completely infiltrates after 0.3 seconds.

[0087] Example 2

[0088] A method for preparing a C-type absorbent core based on long fiber flow guidance includes the following steps:

[0089] (1) Preparation of long fiber hot air nonwoven fabric:

[0090] (1-1) Raw materials: polypropylene (core layer) and EVA (skin layer) bicomponent fibers, fiber length 20cm;

[0091] (1-2) Fiber pretreatment: the front roller speed of the opening machine is 300 r / min, the rear roller speed is 750 r / min, and the roller spacing is 25 mm;

[0092] (1-3) Combing: Pre-combing tooth density 80 teeth / cm, linear velocity 2m / s; main combing needle density 250 needles / cm², linear velocity 3m / s, air pressure -400Pa;

[0093] (1-4) Hot air bonding: Preheating zone temperature 90℃, processing time 20s; melting zone temperature 130℃, processing time 40s; cooling zone temperature 50℃, processing time 15s; hot air velocity 2.0m / s;

[0094] (1-5) Post-processing: Roll temperature 80℃, pressure 0.3MPa, linear speed 4m / s; winding speed 4m / s, tension 50N;

[0095] Performance: Porosity 70%, longitudinal tensile strength 2.5 N / 5 cm, transverse tensile strength 1.8 N / 5 cm.

[0096] (2) Preparation of C-type composite layer:

[0097] (2-1) Spray superabsorbent polymer on the first side of the fluffy nonwoven fabric (30g / m²) and vibrate to make the superabsorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0098] (2-2) Spray hot melt adhesive on one side of the spunlace nonwoven fabric (25g / m²), then cover the adhesive-sprayed side of the spunlace nonwoven fabric with the first side of the fluffy nonwoven fabric sprayed with superabsorbent polymer, and then perform a pressing treatment.

[0099] (2-3) Spray super absorbent polymer on the second side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0100] (2-4) Spray hot melt adhesive on one side of toilet paper (10g / m²), then cover the adhesive side of the toilet paper with the second side of the fluffy non-woven fabric sprayed with super absorbent polymer resin, and then perform a pressing process to form a composite absorbent material.

[0101] (2-5) Transfer the composite absorbent material to the folding machine. The folding machine uses the spunlace nonwoven fabric as the bottom surface to fold the left and right sides of the composite absorbent material upwards to form a C-shaped composite layer with a groove in the middle.

[0102] (3) Core assembly:

[0103] Hot melt adhesive is sprayed onto one side of hot air nonwoven fabric (40g / m²), and the sprayed adhesive side of the hot air nonwoven fabric is covered onto the grooved side of the C-shaped composite layer. Then, the adhesive is pressed to obtain the C-shaped absorbent core.

[0104] Effect Experiment

[0105] According to the People's Republic of China National Standard GB / T28004-2011, the method for measuring leakage in diapers (pads, sheets), the C-type absorbent core of this embodiment was made into a baby diaper as a sample. The sample was placed on an inclined plate with an inclination of (30±2)°, with the usable side facing up. 100 mm was taken from both ends of the center point of the absorbent core of the sample as the test area. 50 ml of test solution was measured and allowed to flow freely to the surface of the sample and along the inclined plate. The experiment was repeated more than six times. The volume of test liquid flowing out from each sample was recorded. The average value was taken after multiple tests. Leakage occurred only in the sixth test, and the leakage amount was 0.6 ml.

[0106] According to the measurement method of rewetting amount in diapers (pads, sheets) in the national standard GB / T28004-2011 of the People's Republic of China, a medium-sized baby diaper made from the C-type absorbent core of this embodiment was used as a sample. 60ml of test solution was allowed to flow freely to the surface of the center of the sample through a funnel. After 5 minutes, the same amount of test solution was injected again through the funnel. After 10 minutes, several layers of filter paper with a diameter of 100mm were placed on the surface of the sample, and a standard pressure block was pressed on the filter paper. After applying pressure for 1 minute, the standard pressure block was removed. This measurement method was repeated multiple times, and the average rewetting amount of the sample was finally measured to be 0.4g, which is lower than the national standard of 10g.

[0107] According to the People's Republic of China National Standard GB / T28004-2011 Method for Measuring Leakage in Diapers (Pads, Sheets), the C-type absorbent core of this embodiment was made into an adult diaper as a sample. The sample was laid flat on a horizontal platform, and 80 ml of test solution was measured using a separatory funnel and poured into the center of the sample at a uniform speed within 30 seconds. After 5 minutes, no liquid leakage was observed around the sample.

[0108] Infiltration test: When using the water-absorbing core of the present invention, 60ml of test solution flows freely through the funnel to the surface of the center of the sample. After multiple tests, on average, the test solution on the surface layer completely infiltrates after 0.5 seconds.

[0109] Example 3

[0110] Reference Figures 1-3 A C-type absorbent core based on long fiber flow guidance, the C-type absorbent core includes an upper flow guiding layer 1 and a lower C-type composite layer 2, the flow guiding layer 1 and the C-type composite layer 2 are bonded together;

[0111] The upper flow guiding layer 1 is made of long fiber hot air nonwoven fabric, which is made of long fibers with a fiber length of 30cm;

[0112] The C-shaped composite layer 2 is formed by folding the composite absorbent material upwards from both sides to create a C-shaped structure with a central groove 6; see reference. Figure 4 The composite absorbent material is composed of toilet paper 3, fluffy nonwoven fabric 4 and spunbond nonwoven fabric 5 layered from top to bottom. The fluffy nonwoven fabric 4 is uniformly distributed with superabsorbent polymer. The fiber pores of the spunbond nonwoven fabric are smaller than the particle size of the superabsorbent polymer, which can prevent the superabsorbent polymer in the fluffy nonwoven fabric 4 from leaking downward.

[0113] The flow guiding layer 1 is located above the trench 6, and the width of the flow guiding layer 1 is greater than the width of the trench 6 and less than the width of the C-type composite layer 2.

[0114] A method for preparing a C-type absorbent core based on long fiber flow guidance includes the following steps:

[0115] (1) Preparation of long fiber hot air nonwoven fabric:

[0116] (1-1) Raw materials: bicomponent fibers of polypropylene (core layer) and EVA (skin layer), fiber length 50cm;

[0117] (1-2) Fiber pretreatment: the front roller speed of the opening machine is 300 r / min, the rear roller speed is 800 r / min, and the roller spacing is 50 mm;

[0118] (1-3) Combing: Pre-combing tooth density 100 teeth / cm, linear velocity 3m / s; main combing needle density 150 needles / cm², linear velocity 3.6m / s, air pressure -400Pa;

[0119] (1-4) Hot air bonding: Preheating zone temperature 110℃, processing time 30s; melting zone temperature 160℃, processing time 60s; cooling zone temperature 70℃, processing time 25s; hot air velocity 3.5m / s;

[0120] (1-5) Post-processing: Roller temperature 100℃, pressure 0.5MPa, linear speed 6m / s; winding speed 6m / s, tension 80N; to obtain long fiber hot air nonwoven fabric with porosity of 60%.

[0121] (2) Preparation of C-type composite layer:

[0122] (2-1) Spray superabsorbent polymer on the first side of the fluffy nonwoven fabric (50g / m²) and vibrate to make the superabsorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0123] (2-2) Spray hot melt adhesive on one side of spunbond nonwoven fabric (30g / m²), then cover the adhesive-sprayed side of the spunbond nonwoven fabric with the first side of the fluffy nonwoven fabric sprayed with superabsorbent polymer, and then perform a pressing treatment.

[0124] (2-3) Spray super absorbent polymer on the second side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric.

[0125] (2-4) Spray hot melt adhesive on one side of toilet paper (15g / m²), then cover the adhesive side of the toilet paper with the second side of the fluffy non-woven fabric sprayed with super absorbent polymer resin, and then perform a pressing process to form a composite absorbent material.

[0126] (2-5) Transfer the composite absorbent material to the folding machine. The folding machine uses spunbond nonwoven fabric as the bottom surface to fold the left and right sides of the composite absorbent material upwards to form a C-shaped composite layer with a groove in the middle.

[0127] (3) Core assembly:

[0128] Hot melt adhesive is sprayed onto one side of a hot air nonwoven fabric (35g / m²), and the adhesive-sprayed side of the hot air nonwoven fabric is placed over the grooved side of the C-shaped composite layer. Then, the adhesive is pressed to obtain the C-shaped absorbent core.

[0129] Effect Experiment

[0130] According to the People's Republic of China National Standard GB / T28004-2011, the method for measuring leakage in diapers (pads, sheets), the C-type absorbent core of this embodiment was made into a baby diaper as a sample. The sample was placed on an inclined plate with an inclination of (30±2)°, with the usable side facing up. 100 mm was taken from both ends of the center point of the absorbent core of the sample as the test area. 50 ml of test solution was measured and allowed to flow freely to the surface of the sample and along the inclined plate. The experiment was repeated more than six times, and the volume of test liquid flowing out from each sample was recorded. The average value was taken after multiple tests. Leakage occurred only in the sixth test, and the leakage amount was 0.4 ml.

[0131] According to the People's Republic of China National Standard GB / T28004-2011, the method for measuring rewetting in diapers (pads, sheets), a medium-sized baby diaper made from the C-type absorbent core of this embodiment was used as a sample. 60ml of test solution was allowed to flow freely to the surface of the center of the sample through a funnel. After 5 minutes, the same amount of test solution was injected again through the funnel. After 10 minutes, several layers of filter paper with a diameter of 100mm were placed on the surface of the sample, and a standard pressure block was pressed on the filter paper. After applying pressure for 1 minute, the standard pressure block was removed. This measurement method was repeated multiple times, and the average rewetting of the sample was finally measured to be 0.5g, which is lower than the national standard of 10g.

[0132] According to the People's Republic of China National Standard GB / T28004-2011 Method for Measuring Leakage in Diapers (Pads, Sheets), the C-type absorbent core of this embodiment was made into an adult diaper as a sample. The sample was laid flat on a horizontal platform, and 80 ml of test solution was measured using a separatory funnel and poured into the center of the sample at a uniform speed within 30 seconds. After 5 minutes, no liquid leakage was observed around the sample.

[0133] Infiltration test: When using the water-absorbing core of the present invention, 60 ml of test solution flows freely through the funnel to the surface of the center of the sample. After multiple tests, on average, the test solution on the surface layer completely infiltrated after 0.4 seconds.

[0134] This invention, through structural innovation using long-fiber hot-air nonwoven fabric and a C-type composite layer, significantly improves the absorption rate and anti-backflow performance of the absorbent core, overcoming the shortcomings of existing technologies and possessing broad application prospects. The manufacturing process of this invention is simple, cost-controllable, and suitable for large-scale production, providing a highly efficient and comfortable new absorbent core solution for the hygiene products industry.

[0135] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A C-type absorbent core based on long fiber flow guidance, characterized in that, The C-type absorbent core includes an upper flow guiding layer and a lower C-type composite layer, with the flow guiding layer and the C-type composite layer bonded together. The upper flow guiding layer is made of long fiber hot air nonwoven fabric, which is made of long fibers with a fiber length of 20~50cm; The C-shaped composite layer is formed by folding the left and right sides of the composite absorbent material upwards to create a C-shaped structure with a central groove. The composite absorbent material is composed of toilet paper, fluffy nonwoven fabric, and dense nonwoven fabric layered from top to bottom. The fluffy nonwoven fabric contains uniformly distributed superabsorbent polymer. The dense nonwoven fabric is made of spunlace nonwoven fabric or spunbond nonwoven fabric, and its fiber pores are smaller than the particle size of the superabsorbent polymer. The flow guiding layer is located above the trench, and the width of the flow guiding layer is greater than the width of the trench and less than the width of the C-type composite layer.

2. The C-type absorbent core based on long fiber flow guidance according to claim 1, characterized in that, The long fibers are bicomponent fibers, with the core layer being a high-melting-point resin with a melting point of 160~200℃ and the sheath being a low-melting-point resin with a melting point of 80~120℃.

3. The C-type absorbent core based on long fiber flow guidance according to claim 1, characterized in that, The porosity of the hot air nonwoven fabric is 60-80%.

4. The C-type absorbent core based on long fiber flow guidance according to claim 1, characterized in that, The toilet paper has a basis weight of 10-25 g / m², and the loose nonwoven fabric has a basis weight of 15-60 g / m². 2 The basis weight of dense nonwoven fabric is 7~40 g / m². 2 The basis weight of hot-air nonwoven fabric is 15~70g / m². 2 .

5. The C-type absorbent core based on long fiber flow guidance according to claim 1, characterized in that, The long-fiber hot-air nonwoven fabric and the C-type composite layer are bonded together with hot melt adhesive.

6. A method for preparing the C-type absorbent core according to claim 1, characterized in that, Includes the following steps: (1) Preparation of long fiber hot air nonwoven fabric: long fibers of 20~50cm are bonded together to form nonwoven fabric; (2) Preparation of C-type composite layer: toilet paper, fluffy non-woven fabric and spunlace non-woven fabric are laminated to make composite absorbent material, and then the left and right sides of the composite absorbent material are folded upward to form a C-type structure. (3) Assemble the core: bond the long fiber hot air nonwoven fabric to the C-type composite layer.

7. The preparation method according to claim 6, characterized in that, The specific steps (1) are as follows: (1-1) Raw material selection: long fibers of bicomponent fiber are selected, in which the core layer is a high melting point resin with a melting point of 160~200℃ and the skin layer is a low melting point resin with a melting point of 80~120℃. (1-2) Fiber pretreatment: The raw material is loosened by an opening machine. The front roller speed of the opening machine is 200~300 r / min, the rear roller speed is 600~800 r / min, the speed ratio is controlled at 2.5~3 times, and the roller spacing is 20~60 mm. (1-3) Carding: The opened fibers are fed into a carding machine for carding treatment. The pre-carding saw tooth density is 80~100 teeth / cm, and the linear speed is 2~3m / s; the main carding needle density is 150~250 needles / cm. 2 Linear velocity 3~4m / s, velocity ratio controlled at 1.2~1.5 times, wind pressure -300~-500Pa; (1-4) Hot air bonding: The combed fibers are bonded in sections to form a non-woven fabric structure. The preheating zone temperature is 90~110℃ and the processing time is 20~30s; the melting zone temperature is 130~170℃ and the processing time is 40~60s; the cooling zone temperature is 50~70℃ and the processing time is 15~25s; the hot air velocity is 2.0~3.5m / s. (1-5) Post-processing: The obtained nonwoven fabric is calendered and wound to obtain the finished nonwoven fabric. The roller temperature is 80~100℃, the pressure is 0.3~0.5MPa, the linear speed is 4~6m / s; the winding speed is 4~6m / s, and the tension is 50~80N.

8. The preparation method according to claim 7, characterized in that, In step (1-1), the core layer is polypropylene and the outer layer is polyethylene.

9. The preparation method according to claim 6, characterized in that, Step (2) specifically involves: (2-1) Spray super absorbent polymer on the first side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric. (2-2) Spray hot melt adhesive on one side of the spunlace nonwoven fabric, then cover the adhesive-sprayed side of the spunlace nonwoven fabric with the first side of the fluffy nonwoven fabric sprayed with superabsorbent polymer, and then perform a pressing treatment. (2-3) Spray super absorbent polymer on the second side of the fluffy nonwoven fabric and vibrate to make the super absorbent polymer evenly distributed in the fluffy nonwoven fabric. (2-4) Spray hot melt adhesive on one side of the toilet paper, then cover the adhesive side of the toilet paper with the second side of the fluffy non-woven fabric sprayed with super absorbent polymer resin, and then perform a pressing process to form a composite absorbent material. (2-5) Transfer the composite absorbent material to the folding machine. The folding machine uses the spunlace nonwoven fabric as the bottom surface to fold the left and right sides of the composite absorbent material upwards to form a C-shaped composite layer with a groove in the middle.

10. The preparation method according to claim 6, characterized in that, The specific steps (3) are as follows: hot melt adhesive is sprayed on one side of the hot air nonwoven fabric, the sprayed adhesive side of the hot air nonwoven fabric is covered on the grooved side of the C-type composite layer, and then the adhesive is pressed to obtain the C-type absorbent core.

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