An anti-edge roll-over care pad and process

Abstract

The application discloses an anti-edge curling nursing pad and a processing technology, and relates to the field of layered products. The nursing pad comprises, from top to bottom, a surface non-woven fabric, an absorbent core, a bottom PE film, and a composite elastic frame between the edges of the surface non-woven fabric and the bottom PE film. The cross section of the composite elastic frame is a shape of a hook, and the inward width is 20-50 mm. The composite elastic frame is made of a blend comprising the following components: 55-65% low-density polyethylene, 25-35% thermoplastic polyurethane, 5-10% nano calcium carbonate, and 1-3% antioxidant. By constructing a composite elastic frame at the composite edges of the surface and the bottom, a rigid skeleton and an elastic buffer structure are constructed by using the blend system of low-density polyethylene and thermoplastic polyurethane, so that the problem of poor elasticity and easy plastic deformation of the traditional single PE film is effectively solved, and the anti-curling ability and long-term use stability of the edge of the nursing pad are significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of layered products, in particular to a nursing pad, and specifically to an anti-edge curling nursing pad and a processing process. Background Art

[0002] Nursing pads, as disposable sanitary care products, are widely used as key nursing supplies for postoperative recovery, incontinence care, and long-term bedridden patients. Their use has expanded from medical institutions to home care, and market demand continues to grow. Nursing pads' core function is to quickly absorb liquids, keep the skin dry, and provide leak-proof isolation through a structured edge, preventing excrement from leaking into bedding and contaminating the patient's skin.

[0003] The structural stability of the edge directly determines the effectiveness of leak prevention and safety. For bedridden patients, the constant pressure on localized areas (such as the sacrum and hips), as well as the repeated friction caused by frequent turning and movement, can significantly accelerate fatigue damage to the edge structure of the nursing pad. Furthermore, when body fluids absorbed by the surface of the nursing pad penetrate into the edge area, they further weaken the material interface and increase the risk of edge structural instability.

[0004] Traditional nursing pad edge treatments often utilize a single-material hot-pressing process. For example, polyethylene (PE) film or spunbond nonwoven fabric is used as the edge substrate, connected to the surface and bottom layers via hot-melt adhesive bonding or heat pressing to form a flat or simple three-dimensional edge structure. To enhance the shaping effect, some solutions increase the thickness of the PE film or raise the hot-pressing temperature to enhance the rigid support of the edge. While this treatment method is simple and low-cost, due to the high material rigidity and weak elastic recovery ability, it is prone to irreversible plastic deformation under long-term dynamic stress, manifesting as curling, warping, and even delamination of the edges. This can easily lead to the loss of the nursing pad's leak-proof barrier function and increase the risk of leakage.

[0005] Therefore, it is necessary to improve the deficiencies in the prior art to solve the above problems. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides an anti-edge curling nursing pad and a processing process.

[0007] To achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: an anti-edge curling nursing pad, comprising: a surface non-woven fabric, an absorbent core, a bottom PE film, and a composite elastic frame located between the edge of the surface non-woven fabric and the bottom PE film;

[0008] The composite elastic frame has a circular cross-section and an inward width of 20-50 mm, and is produced by blow molding a blend comprising the following components:

[0009] Low density polyethylene 55-65%;

[0010] Thermoplastic polyurethane 25-35%;

[0011] Nano calcium carbonate 5-10%;

[0012] Antioxidant 1-3%;

[0013] The thermoplastic polyurethane is composed of 60-70 wt% of soft segment polyether polyol and 30-40 wt% of hard segment MDI-butanediol; the molar ratio of MDI to butanediol is 1:1-1.2.

[0014] In a preferred embodiment of the present invention, the particle size of the nano-calcium carbonate is 40-60 nm, and the surface is modified by a silane coupling agent.

[0015] In a preferred embodiment of the present invention, the antioxidant is an antioxidant 1010 having a hindered phenol structure.

[0016] In a preferred embodiment of the present invention, the thickness of the composite elastic frame is 0.2-0.3 mm, and the edge has a continuous wavy three-dimensional structure with a peak height of 1-3 mm, a wavelength of 4-6 mm, and a sinusoidal cross-section.

[0017] In a preferred embodiment of the present invention, the preparation process of the composite elastic frame comprises the following steps:

[0018] a low-density polyethylene and thermoplastic polyurethane were melt-blended at 170-190 ° C, nano-calcium carbonate and an antioxidant were added, and the mixture was mixed by a twin-screw extruder at a speed of 280-320 rpm to obtain a blend;

[0019] b. The blend is blow-molded into a composite film at 180-200°C, a blow-up ratio of 2-3, and a cooling rate of 12-18°C / s, and then cut to obtain a composite elastic frame.

[0020] In a preferred embodiment of the present invention, the surface non-woven fabric has a gram weight of 40-50 g / m 2 The absorbent core contains 35-45 wt% SAP and 55-65 wt% fluff pulp, with a thickness of 3-4 mm; the thickness of the bottom PE film is 0.02-0.04 mm.

[0021] The present invention provides a treatment process for an anti-edge curling nursing pad, which is characterized by comprising the following steps:

[0022] S1, plasma etching the edge area of ​​the bottom PE film with a width of 10-30 mm to obtain a pretreated bottom PE film;

[0023] S2. placing an edge region of the composite elastic frame with a width of 10-40 mm in a wavy pattern mold, hot pressing the edge region at a temperature of 100-120° C. and a pressure of 0.3-0.5 MPa for 2-4 seconds, and then cooling the edge region to 35-45° C. at a cooling rate of 6-10° C. / s to obtain a pretreated composite elastic frame.

[0024] S3. Apply 0.05-0.1mm thick EVA hot melt adhesive on the edge area where the pretreated bottom PE film extends beyond the absorbent core, overlap the surface non-woven fabric, the absorbent core and the pretreated bottom PE film in sequence, and place the pretreated composite elastic frame between the surface non-woven fabric and the edge of the pretreated bottom PE film with the wavy pattern facing outwards, and use roller hot pressing to obtain an anti-edge curling nursing pad.

[0025] In a preferred embodiment of the present invention, in step S1, the etching power of the plasma etching is 450-550 W, and the processing time is 2-4 s.

[0026] In a preferred embodiment of the present invention, in step S2, the wave crest height of the wavy pattern mold is 1-3 mm, and the wavelength is 4-6 mm.

[0027] In a preferred embodiment of the present invention, in step S3, the temperature of the roller hot pressing lamination is 90-100° C., the pressure is 0.15-0.25 MPa, and the line speed is 8-12 m / min.

[0028] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0029] (1) The present invention provides an edge-curling-resistant nursing pad and a processing process, which constructs a composite elastic frame at the composite edge of the surface layer and the bottom layer, and uses a blend system of low-density polyethylene and thermoplastic polyurethane to construct a rigid skeleton and elastic buffer structure. The basic flexibility is provided by the LDPE linear molecular chain, the TPU soft segment realizes elastic recovery through entropy increase driving, the hard segment forms a physical cross-linking point, and the LDPE crystalline region provides anti-tensile support to limit excessive deformation. Then, the synergistic effect of molecular chain entanglement and physical cross-linking enables the material to absorb stress through the stretching of the soft segment when under pressure, and quickly returns to its original shape after unloading, thereby effectively solving the problem of poor elasticity and easy plastic deformation of traditional single PE film, and significantly improving the anti-curling ability and long-term stability of the nursing pad edge.

[0030] (2) In the present invention, a composite elastic frame with a wavy three-dimensional edge structure is constructed, and the mold is pressurized at a temperature lower than the melting point of the TPU hard segment, so that the molecular chains of the composite film are oriented along the wave and trough directions, inducing the formation of anisotropic strengthening areas with high crystallinity. The specific wavy configuration decomposes the local concentrated stress into a component force along the normal direction of the curved surface, and then utilizes the synergy of structure and molecular orientation to reduce the stress concentration phenomenon of the traditional plane edge and reduce the risk of molecular chain breakage. The rapid cooling and shaping process is used to freeze the molecular chain arrangement state, so that the edge structure can still maintain a stable shape after repeated bending, thereby avoiding the edge curling and delamination problems caused by stress concentration in traditional nursing pads.

[0031] (3) The soft segment and hard segment with appropriate contents in the present invention constitute TPU, which forms a periodically alternating soft phase micro-region and hard phase micro-region cooperative structure through microphase separation. When the edge of the nursing pad is subjected to continuous pressure, the soft segment molecular chain undergoes reversible stretching through the rotation of the COC bond of the main chain and the conformational change of the ether bond, while the hard segment forms a physical cross-linking point with the aromatic ring stacking through hydrogen bonding, locking the excessive slip of the soft segment molecular chain. Furthermore, through the supporting effect of the hard segment crystalline phase and the dynamic recovery ability of the soft segment, the edge morphology can be maintained stable during long-term use, thereby reducing the risk of curling and delamination.

[0032] (4) In the present invention, nano-calcium carbonate modified with a silane coupling agent is added to the composite elastic frame. The surface hydroxyl groups can form hydrogen bonds with the TPU hard segments and interact with the LDPE methylene groups through dispersion forces to construct a three-dimensional network structure of particles and polymers. This network can effectively inhibit the slippage of molecular chains, reduce the creep compliance of the material, and prevent the edges from producing plastic curling. Compared with the traditional PE film's anti-creep mechanism that simply relies on the support of the crystalline phase, the present invention further improves the anti-creep performance through the interface anchoring effect of nanoparticles, ensuring that the nursing pad can maintain its structural integrity under long-term pressure conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive efforts.

[0034] Figure 1 This is a three-dimensional separation structure diagram of a nursing pad according to a preferred embodiment of the present invention;

[0035] In the figure: 1. Surface non-woven fabric; 2. Absorbent core; 3. Bottom PE film; 4. Composite elastic frame. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0038] It should be noted that the raw materials, equipment, reagents, etc. used in the present invention can be purchased from the market or obtained through existing preparation methods.

[0039] like Figure 1 As shown, an anti-edge curling nursing pad includes: a surface non-woven fabric 1, an absorbent core 2, a bottom PE film 3, and a composite elastic frame 4 located between the edges of the surface non-woven fabric 1 and the bottom PE film 3, which are laminated in sequence from top to bottom; the composite elastic frame 4 has a circular cross-section and an inward width of 20-50 mm, and is made by blow molding a blend containing the following components: low-density polyethylene (LDPE) 55-65%; thermoplastic polyurethane (TPU) 25-35%; nano calcium carbonate (n-CaCO3) 5-10%; and antioxidant 1-3%.

[0040] In some specific embodiments, the thermoplastic polyurethane is composed of 60-70 wt% of a soft segment polyether polyol and 30-40 wt% of a hard segment MDI and butanediol; the molar ratio of MDI to butanediol is 1:1-1.2.

[0041] It should be noted that the preparation of thermoplastic polyurethane includes the following steps: reacting polyether polyol with MDI (diphenylmethane diisocyanate) at 70-80°C for 1-2 hours to generate a prepolymer with terminal -NCO groups, adding butanediol, and reacting at 85-95°C for 2-3 hours to obtain thermoplastic polyurethane.

[0042] In some specific embodiments, the particle size of the nano-calcium carbonate is 40-60 nm, and the surface is modified by a silane coupling agent; the antioxidant is an antioxidant 1010 with a hindered phenol structure.

[0043] It should be noted that the modification method of nano-calcium carbonate includes the following steps: mixing a silane coupling agent, ethanol and water in a mass ratio of 1:8-12:0.5-1.5, adjusting the pH to 4-5, hydrolyzing at 25-35°C for 30-60 minutes, adding nano-calcium carbonate, stirring and reacting at 70-80°C under nitrogen protection for 2-4 hours, washing and drying to obtain modified nano-calcium carbonate; wherein the mass ratio of nano-calcium carbonate to silane coupling agent is 95:5.

[0044] In some specific embodiments, the thickness of the composite elastic frame 4 is 0.2-0.3 mm, and the edge has a continuous wavy three-dimensional structure with a peak height of 1-3 mm, a wavelength of 4-6 mm, and a sinusoidal cross-section.

[0045] In some specific embodiments, the preparation process of the composite elastic frame 4 includes the following steps:

[0046] a low-density polyethylene and thermoplastic polyurethane were melt-blended at 170-190 ° C, nano-calcium carbonate and an antioxidant were added, and the mixture was mixed by a twin-screw extruder at a speed of 280-320 rpm to obtain a blend;

[0047] b. The blend is blow-molded into a composite film at 180-200 ° C, a blow-up ratio of 2-3, and a cooling rate of 12-18 ° C / s, and cut to obtain a composite elastic frame 4.

[0048] In some specific embodiments, the surface nonwoven fabric 1 has a gram weight of 40-50 g / m 2 The absorbent core 2 contains 35-45 wt% SAP and 55-65 wt% fluff pulp, with a thickness of 3-4 mm; the thickness of the bottom PE film 3 is 0.02-0.04 mm.

[0049] The present invention provides a treatment process for an anti-edge curling nursing pad, comprising the following steps:

[0050] S1, plasma etching the edge area of ​​the bottom PE film 3 to obtain a pretreated bottom PE film 3; wherein the width of the edge area of ​​the bottom PE film 3 is 10-30 mm;

[0051] S2. placing the edge region of the composite elastic frame 4 in a wavy pattern mold, hot pressing at a temperature of 100-120° C. and a pressure of 0.3-0.5 MPa for 2-4 seconds, and then cooling to 35-45° C. at a cooling rate of 6-10° C. / s to obtain a pretreated composite elastic frame 4; wherein the width of the edge region of the composite elastic frame 4 is 10-40 mm;

[0052] S3. Apply 0.05-0.1mm thick EVA hot melt adhesive on the edge area where the pretreated bottom PE film 3 extends beyond the absorbent core 2, overlap the surface non-woven fabric 1, the absorbent core 2 and the pretreated bottom PE film 3 in sequence, and place the pretreated composite elastic frame 4 between the edge of the surface non-woven fabric 1 and the pretreated bottom PE film 3, with the wavy pattern facing outward, and obtain an anti-edge curling nursing pad through roller hot pressing.

[0053] In some specific embodiments, in step S1, the etching power of the plasma etching is 450-550 W, and the processing time is 2-4 s.

[0054] In some specific embodiments, in step S2, the wave crest height of the wavy pattern mold is 1-3 mm, and the wavelength is 4-6 mm.

[0055] In some specific embodiments, in step S3, the temperature of the roller hot pressing lamination is 90-100° C., the pressure is 0.15-0.25 MPa, and the line speed is 8-12 m / min.

[0056] In order to further make the purpose and effect of the present invention simple and easy to understand, the present invention is further described in conjunction with the following specific examples and comparative examples, but the present invention is not limited to the scope of the embodiments.

[0057] It should be noted that, in the examples and comparative examples, the description of the preparation of raw materials is as follows: LDPE: density 0.921 g / m 2 , brand Q210, molecular weight 200000, purchased from Shanghai Handar New Materials; n-CaCO3: purity ≥99%, particle size 50 nm, brand DK503, purchased from Beijing Dekedaojin; antioxidant 1010: purity ≥99%, purchased from Shandong Aicai Biological; polyether polyol: purity ≥99%, CAS number 9001-11-2, purchased from Shandong Shengyong Biological; MDI: CAS number 101-68-8, purchased from Jiangsu Bosite Chemical; butanediol: density 1.0 g / m 2 , purity ≥99%, purchased from Shandong Youwang Chemical; silane coupling agent KH550: purity ≥99%, purchased from Shandong Jinli Chemical; SAP: purity ≥99%, purchased from Zhengzhou Chengjin Chemical.

[0058] The raw material ratios of the composite elastic frame 4 in Examples 1-7 are different, as shown in Table 1, and the raw materials are measured by mass fraction.

[0059] Table 1: Raw material ratios of the composite elastic frame 4 in Examples 1-7

[0060] Example 1

[0061] A preparation process of an anti-edge curling nursing pad comprises the following steps:

[0062] S1. Weigh 65 wt% of a polyether polyol and 35 wt% of MDI and butanediol, respectively, with a molar ratio of MDI to butanediol of 1:1.1; react the polyether polyol and MDI at 70°C for 2 h, then add butanediol and react at 90°C for 2 h to obtain a thermoplastic polyurethane;

[0063] S2. KH550, ethanol, and water were mixed in a mass ratio of 1:10:1, the pH was adjusted to 4.5, and the mixture was hydrolyzed at 30°C for 40 min. n-CaCO3 was added, and the mixture was stirred and reacted at 80°C under nitrogen for 3 h. The mixture was washed three times with anhydrous ethanol and dried in vacuo at 80°C for 6 h to obtain modified n-CaCO3; wherein the mass ratio of n-CaCO3 to KH550 was 95:5;

[0064] S3. LDPE and TPU were melt-blended at 180° C., modified n-CaCO 3 and antioxidant 1010 were added, and the mixture was kneaded through a twin-screw extruder at a speed of 300 rpm to obtain a blend; the blend was blow-molded into a composite film at 190° C., a blow-up ratio of 3, and a cooling rate of 15° C. / s, and the composite elastic frame 4 was cut to obtain a composite elastic frame 4 having an outer side of 82 cm*62 cm, an inner side of 78 cm*58 cm, and a thickness of 0.3 mm;

[0065] S4, 40 wt% SAP and 60 wt% fluff pulp were evenly dispersed at a wind speed of 12 m / s to form a density of 0.34 g / cm on the forming mesh curtain. 3 , a fluffy layer with a thickness of 3.5 mm, cut to obtain an absorbent core 2 with a size of 73 cm*53 cm;

[0066] S5, treating the edge region of the bottom PE film 3 with an area of ​​80 cm*60 cm and a thickness of 0.03 mm with plasma etching at an etching power of 500 W for 3 s to obtain a pretreated bottom PE film 3; wherein the width of the edge region of the bottom PE film 3 is 20 mm;

[0067] S6. Place the edge region of the composite elastic frame 4 in a wavy pattern mold with a peak height of 2 mm and a wavelength of 5 mm, hot press for 3 s at a temperature of 110°C and a pressure of 0.4 MPa, and then cool to 40°C at a cooling rate of 8°C / s to obtain a pretreated composite elastic frame 4 with an edge width of 20 mm, a peak height of 2 mm, a wavelength of 5 mm, and a sinusoidal cross section; wherein the width of the edge region of the composite elastic frame 4 is 20 mm;

[0068] S7, on the edge area of the pretreated bottom layer PE film 3 beyond the absorbent core 2, 0.1 mm thick EVA hot melt adhesive is coated, 80 cm*60 cm, 40 g / m 2 The surface layer non-woven fabric 1, the absorbent core 2 and the pretreated bottom layer PE film 3 are overlapped in sequence, and the edge 20 mm of the pretreated composite elastic frame 4 is arranged between the surface layer non-woven fabric 1 and the edge of the pretreated bottom layer PE film 3, the wavy lines face outward, and the composite is hot-pressed by a roller at a temperature of 90 ℃, a pressure of 0.2 MPa and a linear speed of 10 m / min to obtain an anti-edge curling care pad.

[0069] In order to verify the success of the care pad in Example 1, the composite structure of the surface layer non-woven fabric 1, the composite elastic frame 4 and the bottom layer PE film 3 of the care pad prepared in Example 1 is cut into a sample with a width of 20 mm and a length of 100 mm, the composite interface of 20 mm at one end is manually separated, and is clamped in the upper and lower clamps of a universal material testing machine, respectively, and is subjected to 180° peeling at a speed of 50 mm / min, and the maximum force value in the peeling process is recorded by parallel testing for 3 times; the peeling strength is 2.42 N / 20mm.

[0070] Specifically, after the bottom layer PE film 3 is treated by plasma etching, polar groups such as hydroxyl and carboxyl groups are introduced on the surface, the surface contact angle is reduced, and the wettability with EVA hot melt adhesive is improved. In the hot melt composite process, the adhesive layer can fully infiltrate the rough structure on the surface of the PE film, and high-strength bonding is achieved through mechanical interlocking and molecular diffusion. Compared with traditional physical adsorption type adhesion, the interfacial bonding strength is higher, effectively resisting swelling failure after liquid penetration, and ensuring that the edge structure can still maintain stable leak-proof barrier function in a humid environment.

[0071] A dynamic bending fatigue testing machine is used to cut the composite elastic frame 4 at the edge of the care pad into a strip-shaped sample with a length of 10 cm and a width of 2 cm, which is clamped in the clamps with a distance of 5 cm, and a reciprocating bending angle of ±30° is set, the cycle frequency is 1 / s, the total cycle number is 500, and the elastic recovery rate is recorded by parallel testing for 3 times; the elastic recovery rate is 93.5%.

[0072] Specifically, the physical crosslinking points formed by the TPU hard segment limit the excessive slipping of molecular chains in deformation, and the soft segment polyether chain restores the initial morphology by chain segment curling after unloading, and the three-dimensional network structure constructed by the nano calcium carbonate particles further improves the fatigue resistance of the material, realizes a higher elastic recovery rate, and thus ensures the stability of the edge structure of the care pad in long-term use. Example 2

[0073] This embodiment is basically the same as Example 1, and the difference lies in that the raw material ratio is different, as shown in Table 1. Example 3

[0074] This embodiment is basically the same as embodiment 1, except that the raw material ratios are different, as shown in Table 1. Example 4

[0075] This embodiment is basically the same as embodiment 1, except that: the raw material ratio is different, as shown in Table 1; in step S6, the peak height of the wavy pattern mold is 1 mm, and the peak height of the wavy three-dimensional structure in the composite elastic frame 4 is 1 mm. Example 5

[0076] This embodiment is basically the same as embodiment 1, except that: the raw material ratio is different, as shown in Table 1; in step S6, the peak height of the wavy pattern mold is 3 mm, and the peak height of the wavy three-dimensional structure in the composite elastic frame 4 is 3 mm. Example 6

[0077] This embodiment is basically the same as Example 1, except that: the raw material ratio is different, as shown in Table 1; in step S1, the thermoplastic polyurethane is composed of 70 wt% of soft segment polyether polyol and 30 wt% of hard segment MDI and butanediol. Example 7

[0078] This embodiment is basically the same as Example 1, except that: the raw material ratio is different, as shown in Table 1; in step S1, the thermoplastic polyurethane is composed of 60 wt% of soft segment polyether polyol and 40 wt% of hard segment MDI and butanediol.

[0079] Comparative Example 1

[0080] Commercially available nursing pads: The structure includes non-woven fabric, PE film, and a core composed of SAP and fluff pulp located between the non-woven fabric and the PE film. The size is 80 cm*60 cm and was purchased from Henan Chongde Medical Equipment.

[0081] Comparative Example 2

[0082] This comparative example is basically the same as Example 1, except that the contents of thermoplastic polyurethane are different. Specifically, the TPU content is 20 wt % and the LDPE content is 70 wt %.

[0083] Comparative Example 3

[0084] This comparative example is basically the same as Example 1, except that the contents of thermoplastic polyurethane are different. Specifically, the TPU content is 40 wt % and the LDPE content is 50 wt %.

[0085] Comparative Example 4

[0086] This comparative example is basically the same as Example 1, except that the contents of the soft segment and hard segment in the thermoplastic polyurethane are different. Specifically, in step S1, the thermoplastic polyurethane is composed of 75 wt% of the soft segment polyether polyol and 25 wt% of the hard segment MDI and butanediol.

[0087] Comparative Example 5

[0088] This comparative example is basically the same as Example 1, except that the contents of the soft segment and hard segment in the thermoplastic polyurethane are different. Specifically, in step S1, the thermoplastic polyurethane is composed of 55 wt% of the soft segment polyether polyol and 45 wt% of the hard segment MDI and butanediol.

[0089] Comparative Example 6

[0090] This comparative example is basically the same as Example 1, except that: n-CaCO3 is not added, there is no S2 step, and the S3 step is specifically as follows: LDPE and TPU are melt-blended at 180°C, antioxidant 1010 is added, and the mixture is mixed at a speed of 300 rpm through a twin-screw extruder to obtain a blend; the blend is formed into a composite film by a blow molding process at 190°C, a blow-up ratio of 3, and a cooling rate of 15°C / s, and the composite elastic frame 4 is cut to obtain a composite elastic frame 4 with an outer side of 82 cm*62 cm, an inner side of 78 cm*58 cm, and a thickness of 0.3 mm.

[0091] Comparative Example 7

[0092] This comparative example is basically the same as Example 1, except that the composite elastic frame 4 does not have a wavy three-dimensional structure and does not have step S6.

[0093] Comparative Example 8

[0094] This comparative example is basically the same as Example 1, with the difference being that the peak heights of the wavy three-dimensional structure are different. In step S6, the peak height of the wavy pattern mold is 0.5 mm, and the peak height of the wavy three-dimensional structure in the composite elastic frame 4 is 0.5 mm.

[0095] Comparative Example 9

[0096] This comparative example is basically the same as Example 1, with the difference being that the peak heights of the wavy three-dimensional structure are different. In step S6, the peak height of the wavy pattern mold is 3.5 mm, and the peak height of the wavy three-dimensional structure in the composite elastic frame 4 is 3.5 mm.

[0097] Performance testing: The nursing pads obtained in Examples 1-7, Comparative Examples 2-9, and the commercially available nursing pad of Comparative Example 1 were tested for anti-curling performance. The results are shown in Table 2.

[0098] Anti-curling test: The nursing pad was fixed in a constant temperature and humidity chamber at 37°C and 50% humidity. A constant load of 4 kPa, equivalent to the average pressure of the human sacrum and coccyx, was applied to the edge area using an arc-shaped indenter for 12 hours. The load was then unloaded. The test was repeated three times in parallel, and the edge curling height was recorded.

[0099] Table 2: Performance test results of nursing pads of Examples 1-7 and Comparative Examples 1-9

[0100]

[0101] As shown in Table 2:

[0102] By comparing Examples 1-7 with Comparative Example 1, it can be seen that the traditional sandwich structure relies on hot-pressing the edge of a single PE film. The molecular chain of the PE film is a linear polyethylene structure and lacks physical cross-linking points. Under continuous pressure, the molecular chain is prone to irreversible slippage, resulting in a curling height of 8.6 mm.

[0103] By comparing Examples 1-7 with Comparative Examples 2-3, it can be seen that: in Examples 1-3, the TPU content is 25-35%. At this time, the LDPE linear chain and the TPU soft and hard segments form an interpenetrating network, the LDPE crystalline phase provides tensile support, the TPU hard segment forms hydrogen bond crosslinking points, and the soft segment provides elastic recovery, achieving an elastic recovery rate of >90% and an edge curling height of <2 mm; in Comparative Example 2, the TPU proportion is too low, resulting in insufficient physical crosslinking points in the hard segment, which cannot effectively limit the slippage of the LDPE molecular chain. When the edge is compressed, the material undergoes plastic deformation due to the weak rigid skeleton, and the curling height increases to 4.2 mm; in Comparative Example 3, the TPU proportion is too high, which causes a relative decrease in the soft segment proportion, reduces the material flexibility, and causes the hard segment aggregation to increase the local rigidity. After repeated bending, the hard segment crystalline phase is easily broken, and the curling height increases to 5.1 mm.

[0104] By comparing Examples 1-7 with Comparative Examples 4-5, it can be seen that: in Example 1 and Examples 6-7, the appropriate TPU hard segment content forms periodically alternating soft phase / hard phase micro-regions through microphase separation, and the hard segment forms physical cross-linking points with the aromatic ring stacking through hydrogen bonding, thereby locking the excessive slip of the soft segment; the soft segment (polyether polyol) achieves reversible stretching through COC bond rotation, synergistically maintaining the stability of the edge morphology; in Comparative Example 4, the hard segment content is too low, resulting in insufficient physical cross-linking density, and the soft segment molecular chain is prone to irreversible stretching under stress. The edge cannot fully recover after being compressed, and the curling height increases to 3.8 mm; in Comparative Example 5, the hard segment content is too high, which increases the rigidity of the material and weakens the elastic buffering effect of the soft segment. When the edge is rubbed, the hard segment crystalline phase is prone to break due to stress concentration, and the curling height increases to 4.5 mm.

[0105] By comparing Examples 1-7 with Comparative Example 6, it can be seen that the absence of n-CaCO3 loses the three-dimensional network structure of particles and polymers, lacks the interface anchoring effect, increases the creep compliance of the material, and produces plastic curling at the edge after long-term compression, with the height rising to 5.8 mm.

[0106] By comparing Examples 1-7 with Comparative Example 7, it can be seen that the composite elastic frame 4 of Comparative Example 7 has no wavy three-dimensional structure, that is, the edge is flat. When under pressure, the stress is concentrated in the local area, and the disordered arrangement of the molecular chains aggravates the chain breakage, causing the molecular chains to slip in a single direction and break, and the curling height rises to 6.3 mm.

[0107] By comparing Examples 1-7 with Comparative Examples 8-9, it can be seen that in Example 1 and Examples 4-5, the appropriate peak height enables the wavy structure of the composite elastic frame 4 to disperse stress through the curved surface and avoid structural instability caused by excessively high peaks. When the peak height is 2 mm, the stress dispersion effect is optimal, and the curling height is 1.3 mm; in Comparative Example 8, the peak is too low and the curvature radius is too small, which cannot effectively disperse stress. Local stress concentration still exists at the edge, the molecular chain is easily broken, and the curling height rises to 3.7 mm; in Comparative Example 9, the peak is too high and the curvature radius is too large, resulting in increased structural rigidity, weakening the stress dispersion effect, and the molecular chain at the peak is broken due to excessive stretching. At the same time, it is difficult for the mold to cool and shape evenly during hot pressing, and the curling height increases to 4.4 mm.

[0108] The above description is based on the ideal embodiment of the present invention. 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 present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered as illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims, not the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0109] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An anti-edge curling nursing pad, characterized in that: include: A surface non-woven fabric, an absorbent core, a bottom PE film, and a composite elastic frame located between the edge of the surface non-woven fabric and the bottom PE film, which are laminated sequentially from top to bottom; The composite elastic frame has a circular cross-section and an inward width of 20-50 mm, and is produced by blow molding a blend comprising the following components: Low density polyethylene 55-65%; Thermoplastic polyurethane 25-35%; Nano calcium carbonate 5-10%; Antioxidant 1-3%; The thermoplastic polyurethane is composed of 60-70 wt% of soft segment polyether polyol and 30-40 wt% of hard segment MDI-butanediol; the molar ratio of MDI to butanediol is 1:1-1.2; the thickness of the composite elastic frame is 0.2-0.3 mm, and the edge has a continuous wavy three-dimensional structure with a peak height of 1-3 mm, a wavelength of 4-6 mm, and a sinusoidal cross-section.

2. The anti-edge curling nursing pad according to claim 1, characterized in that: The particle size of the nano calcium carbonate is 40-60 nm, and the surface is modified by a silane coupling agent.

3. The anti-edge curling nursing pad according to claim 1, characterized in that: The antioxidant is antioxidant 1010 with a hindered phenol structure.

4. The anti-edge curling nursing pad according to claim 1, characterized in that: The preparation process of the composite elastic frame comprises the following steps: a low-density polyethylene and thermoplastic polyurethane were melt-blended at 170-190 ° C, nano-calcium carbonate and an antioxidant were added, and the mixture was mixed by a twin-screw extruder at a speed of 280-320 rpm to obtain a blend; b. The blend is blow-molded into a composite film at 180-200°C, a blow-up ratio of 2-3, and a cooling rate of 12-18°C / s, and then cut to obtain a composite elastic frame.

5. The anti-edge curling nursing pad according to claim 1, characterized in that: The surface nonwoven fabric has a gram weight of 40-50 g / m 2 The absorbent core contains 35-45 wt% SAP and 55-65 wt% fluff pulp, with a thickness of 3-4 mm; the thickness of the bottom PE film is 0.02-0.04 mm.

6. A treatment process for an anti-edge curling nursing pad according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, plasma etching the edge area of ​​the bottom PE film with a width of 10-30 mm to obtain a pretreated bottom PE film; S2. placing an edge region of the composite elastic frame with a width of 10-40 mm in a wavy pattern mold, hot pressing the edge region at a temperature of 100-120° C. and a pressure of 0.3-0.5 MPa for 2-4 seconds, and then cooling the edge region to 35-45° C. at a cooling rate of 6-10° C. / s to obtain a pretreated composite elastic frame. S3. Apply 0.05-0.1mm thick EVA hot melt adhesive on the edge area where the pretreated bottom PE film extends beyond the absorbent core, overlap the surface non-woven fabric, the absorbent core and the pretreated bottom PE film in sequence, and place the pretreated composite elastic frame between the surface non-woven fabric and the edge of the pretreated bottom PE film with the wavy pattern facing outwards, and use roller hot pressing to obtain an anti-edge curling nursing pad.

7. The processing method for an anti-edge curling nursing pad according to claim 6, characterized in that: In the step S1, the etching power of the plasma etching is 450-550 W, and the processing time is 2-4 s.

8. The processing method for an anti-edge curling nursing pad according to claim 6, characterized in that: In the step S2, the wave crest height of the wavy pattern mold is 1-3 mm, and the wavelength is 4-6 mm.

9. The processing method for an anti-edge curling nursing pad according to claim 6, characterized in that: In the step S3, the temperature of the roller hot pressing composite is 90-100° C., the pressure is 0.15-0.25 MPa, and the line speed is 8-12 m / min.

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