A heat-activated dissolving disposable hygiene article and a method of making the same

Abstract

The present application discloses a kind of heat-triggered dissolution type disposable sanitary products and its preparation method.The sanitary products include adult paper diaper, child paper diaper, disposable bed sheet and disposable hospital gown, which are characterized by: interlayer adhesion is realized by heat-sensitive adhesive with melting point controlled in the range of 42 to 50°C between layers; the structure remains intact and does not disintegrate within 24 hours when in contact with ≤40°C urine or body fluid in use state; when put into hot water with temperature ≥42°C, it disintegrates into fragments with maximum diameter not exceeding 2 centimeters within 3 minutes; all skeleton materials are biodegradable materials, including viscose fiber non-woven fabric, starch-based superabsorbent resin and paper-based impermeable membrane, without polypropylene, polyethylene and other non-degradable plastics; the disintegration product can be completely biodegraded within 48 hours in municipal sewage system, without microplastic residue, meeting the dispersible standard of GB / T 41244-2022 and the comprehensive discharge standard of GB 8978 sewage. The present application is particularly suitable for medical institution scenarios, realizing on-site hot water disintegration treatment of medical waste, greatly reducing disposal cost and cross-infection risk, and having important environmental value and commercial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of hygiene products and functional textile materials, specifically relating to a disposable hygiene product and its preparation method that achieves rapid dissolution through a heat-triggered mechanism, including adult diapers, children's diapers, disposable bed sheets, and disposable hospital gowns (patient gowns). This invention is particularly suitable for medical institution settings. After use, the product can be treated with hot water (≥42°C) to achieve on-site disintegration, eliminating the high cost and safety risks of special collection and disposal of medical waste. At the same time, all materials are biodegradable, and the disintegration products can be completely degraded in the sewage treatment system, complying with the GB / T 41244-2022 flushable standard and the GB 8978 integrated wastewater discharge standard. Background Technology

[0002] Disposable hygiene products (adult diapers, children's diapers, disposable bed sheets, hospital gowns, etc.) are indispensable consumables in the field of health and hygiene in modern society. However, existing products have the following serious problems: (1) Traditional disposable hygiene products use a large amount of non-degradable synthetic plastic materials such as polypropylene (PP) nonwoven fabric and polyethylene (PE) film. More than 300 billion diapers are consumed globally each year, of which adult diapers are growing rapidly with the aging society. The consumption of bed sheets and hospital gowns in medical institutions is also extremely large. After these products are used, they are sent to landfills or incinerated. The plastic components take hundreds of years to degrade and produce a large amount of microplastics, which seriously pollute the soil and water. (2) In medical institutions, disposable bed sheets, hospital gowns and the like are managed as medical waste after use. They need to be collected separately, sterilized by high temperature steaming or incinerated. The disposal cost is high (the disposal cost of infectious waste is about RMB 3,000 to 6,000 per ton), the operation procedure is cumbersome, and there is a risk of cross-infection. Adult diapers and children's diapers also face disposal problems - mixing them with medical waste is extremely costly, while mixing them with domestic waste poses a health and safety hazard. (3) Existing flushable sanitary products have the following main problems: the disintegration products (such as PP / PE fiber fragments) are microplastics, which do not conform to the environmental protection trend; the melting point of existing hot melt adhesives is too high (usually ≥80°C), which cannot be triggered by hot water in the ward (42 to 45°C); the flushability test standards (INDA / EDANA GD4, GB / T41244-2022) have stricter requirements for the biodegradability of materials, which are difficult for traditional PP / PE materials to pass. (4) At present, there are no sanitary product patents or products on the market that specifically meet the technical requirements of "42°C hot water trigger, dissolves into fragments of ≤2 cm within 3 minutes, tolerates urine for 24 hours, and all materials are biodegradable".

[0003] The following are the representative existing technical solutions known at present and their main shortcomings: Firstly, most brands use polypropylene / polyethylene (PP / PE) based disposable diapers and sheets, but their main drawback is that PP / PE fibers are non-degradable, are microplastics, and their emissions are non-compliant. Secondly, the main drawback of the polyvinyl alcohol (PVA) water-soluble material solution reported in the research is that the cost is 3 to 4 times higher than that of traditional products, and the dissolution temperature is difficult to control precisely, posing a safety risk of triggering dissolution when the temperature is below body temperature. Third, the main drawback of the materials that partially dissolve below 40°C reported in the research is that body temperature can trigger dissolution during use, resulting in an extremely high risk of accidental dissolution. Fourth, the low-temperature water-soluble PVA (30°C type) material used in the expired patents has a trigger temperature lower than the human body temperature, and the risk of accidental dissolution is extremely high. Fifth, the technical solution proposed in this application is a completely new combination of technologies, with 42°C hot water triggering, 24-hour urine tolerance, and full material degradability as its core features, filling the gaps in the above four types of existing technologies. Summary of the Invention

[0004] This invention aims to provide a heat-triggered dissolving disposable hygiene product and its preparation method, solving the following technical problems: (1) The product remains structurally intact and does not disintegrate under the conditions of use (≤40°C urine / body fluid contact for 24 hours), and rapidly disintegrates into fragments with a diameter of ≤2 cm within 3 minutes in hot water (≥42°C); (2) The disintegration products (cellulose fibers, starch materials, paper-based materials) can be completely biodegraded in the urban sewage system within 48 hours, without producing microplastic residues, and meet the GB / T 41244-2022 flushable standard and GB 8978 integrated sewage discharge standard; (3) Use hot water (42°C) as the trigger condition. This temperature is easily achievable by hospital and home hot water equipment. The operation is simple and will not cause burns to the human body (below the skin burn threshold of 45°C). (4) Construct a complete product system covering adult diapers, children's diapers, disposable bed sheets, and disposable hospital gowns, with each product using a unified heat-sensitive dissolving technology platform; (5) Provide a low-cost, industrially feasible preparation solution.

[0005] The core technical features of this invention are as follows: ① Low-Temperature Heat-Sensitive Adhesive System: Develop modified starch-based or biodegradable polyester-based hot melt adhesives with precisely controlled melting / softening points within the range of 42 to 50°C, serving as the sole structural adhesive between layers. In environments ≤40°C (such as urine at body temperature of 37°C, under normal storage conditions), the adhesive remains solid and provides sufficient interlayer bonding force, ensuring product structural integrity without any changes within 24 hours; in hot water at ≥42°C, the adhesive melts and fails, the layers lose adhesion, and automatically separate and disintegrate. ② Fully Biodegradable Framework Material System: All framework materials (non-woven fabric, absorbent core, and geomembrane) are made of biodegradable materials: the non-woven fabric layer uses viscose or Lyocell non-woven fabric, conforming to the GB / T 41244-2022 flushable standard, and has been verified as fully biodegradable in wastewater treatment plants; the absorbent core uses a mixture of viscose fiber fluff pulp and starch-based superabsorbent resin, which can be completely degraded in wastewater treatment plants within 48 hours; the geomembrane layer uses a paper-based composite geomembrane, with both the paper base and coating being biodegradable materials. ③ The product as a whole does not contain non-degradable plastics such as PP / PE: Each layer contains no non-degradable synthetic plastics such as polypropylene, polyethylene, or polyethylene terephthalate, eliminating the source of microplastics. ④ Rapid Disintegration Mechanism: Dot-matrix heat-sensitive adhesive bonding (spacing 15 to 40 mm) ensures that all adhesive points fail within 3 minutes in hot water at no less than 42°C, and each layer separates and breaks into fragments with a diameter of no more than 2 cm. Detailed Implementation

[0006] Example 1: Heat-triggered dissolving adult diapers Raw materials and formula Heat-triggered dissolving adult diapers are composed of the following layers: The skin-friendly surface layer uses perforated viscose fiber nonwoven fabric with a basis weight of 22 g / m², is white, and has soft, skin-friendly properties; the dispersion and diversion layer uses viscose fiber hot-air nonwoven fabric with a basis weight of 35 g / m²; the absorbent core layer is made of viscose fiber fluff pulp and starch-based superabsorbent polymer (SAP) at a mass ratio of 4:6, with a total basis weight of 280 g / m², a thickness of approximately 8 mm, and an SAP content of 60% by weight, with an absorbency of no less than 350 g / m²; the leak-proof bottom layer uses paper-based polylactic acid (PLA). A) A breathable composite membrane with a basis weight of 50 g / m²; the outer layer is wrapped with a nonwoven fabric made of viscose fiber spunbond nonwoven fabric with a basis weight of 18 g / m²; the waist fasteners are paper-based hook and loop fasteners with viscose fiber as the base material and a water-soluble adhesive coating, which will detach in hot water at a temperature not lower than 42°C; the elastic waistband is made of viscose fiber elastic strips bonded with heat-sensitive adhesive with an elongation of 100%; the bonding between the layers is done by a modified starch-based hot melt adhesive in a dot matrix coating, the hot melt adhesive has a melting point of 44°C, a coating amount of 12 g / m², and a spacing of 30 mm between adjacent dots. Viscose short fibers (1.7 dtex × 38 mm) are opened, carded, laid into a web, hydroentangled (100 to 200 bar water jet), dried, and wound to obtain a washable viscose nonwoven fabric with a basis weight of 18 to 22 g / m². Tapioca starch and acrylic acid are grafted and polymerized at a mass ratio of 4:6 to obtain starch-based SAP with a water absorption ratio of 150 times and a particle size of 0.3 to 0.8 mm. Modified corn starch, glycerin (plasticizer), and rosin (tackifier) ​​are mixed at a mass ratio of 7:2:1, extruded and granulated to obtain a modified starch-based hot melt adhesive with a softening point of 44°C. The materials are stacked sequentially, and paper-based waistbands and elastic waistbands are installed through a dot matrix hot melt adhesive coating head at 95°C. The adhesive is then cut into standard adult diaper sizes and packaged in single-piece PVA water-soluble film.

[0007] All performance tests of the product in this embodiment met the expected requirements. The specific results are as follows: (1) Urine tolerance test: The product was immersed in artificial urine at a temperature of 37±1°C for 24 hours. The product structure remained intact, with no disintegration, softening, or adhesion failure. It was deemed qualified. (2) Disintegration trigger test: The product was immersed in hot water at 42±1°C. The product completely disintegrated within 3 minutes. The diameter of all fragments did not exceed 2 cm. It was deemed qualified. (3) Fragment biodegradability test: The disintegrated fragments were placed in the activated sludge environment of an urban sewage treatment plant for 48 hours. The degradation rate was greater than 90%, with no microplastic residue. It met the GB / T 41244-2022 standard. It was deemed qualified. (4) Liquid absorption test: The liquid absorption was measured according to the GB / T 28004 method. The liquid absorption was 385 grams per tablet. It was deemed qualified. (5) Chemical Oxygen Demand (COD) Contribution Test: Dissolve one product in 10 liters of water and the COD value is measured to be 350 mg / L, which meets the GB 8978 Class III emission standard and is deemed qualified. (6) Waist Patch Disintegration Test: Place the product in 42°C hot water and the paper-based waist patch falls off within 30 seconds, which is deemed qualified.

[0008] Example 2: Heat-triggered dissolving baby diapers Raw materials and formula Heat-triggered dissolving baby diapers are composed of the following layers: the skin-friendly surface layer uses small-pore perforated viscose fiber nonwoven fabric with a basis weight of 20 grams per square meter, providing soft and skin-friendly properties; the dispersion and diversion layer uses viscose fiber hot-air nonwoven fabric with a basis weight of 30 grams per square meter; the absorbent core layer is made of viscose fiber fluff pulp and starch-based superabsorbent polymer (SAP) mixed in a 5:5 mass ratio, with a total basis weight of 200 grams per square meter and a thickness of approximately 6 millimeters, of which SAP content is 50% by weight. The liquid absorption capacity is not less than 220 grams; the impermeable bottom layer is made of paper-based PLA breathable composite membrane with a basis weight of 40 grams per square meter; the outer layer is wrapped with non-woven fabric made of viscose fiber spunbond non-woven fabric with a basis weight of 16 grams per square meter; the elastic waistband is made of viscose fiber elastic strip (thin version) bonded with heat-sensitive adhesive with an elongation of 80%; the bonding between each layer is made by dot matrix coating with modified starch-based hot melt adhesive, the hot melt adhesive has a melting point of 43°C, a coating amount of 10 grams per square meter, and an adjacent dot matrix spacing of 25 millimeters.

[0009] The performance test results of the product in this embodiment are as follows: (1) Urine tolerance test: The product was continuously soaked in artificial urine at a temperature of 37±1°C for 24 hours. The product structure was intact and there was no disintegration. It was deemed qualified. (2) Disintegration trigger test: The product was immersed in hot water at 42±1°C. The product completely disintegrated within 2.5 minutes. The diameter of all fragments did not exceed 2 cm. It was deemed qualified. (3) Liquid absorption test: According to the method of GB / T 28004, the liquid absorption was 248 grams per tablet. It was deemed qualified. (4) Fragment degradation test: The disintegrated fragments were placed in the activated sludge environment of the sewage treatment plant for 48 hours. The degradation rate was greater than 92%. It was deemed qualified. (5) Production cost assessment: The estimated production cost per tablet is about RMB 1.3 to 1.6. The traditional ordinary version is about RMB 0.8 to 1.0 per tablet. The premium is about 1.5 to 1.6 times. The cost is within an acceptable range.

[0010] Example 3: Heat-triggered dissolving disposable bed sheet Raw materials and formula The heat-triggered dissolving disposable bed sheet adopts a three-layer composite structure, and the materials of each layer are as follows: the upper surface layer (skin contact side) is made of white viscose spunbond nonwoven fabric with a basis weight of 35 grams per square meter; the middle waterproof layer is made of wet-strength paper-based PLA composite film with a basis weight of 30 grams per square meter; the lower surface layer (bed surface contact side) is made of viscose spunbond nonwoven fabric with a basis weight of 30 grams per square meter; the bonding between each layer is achieved by a modified starch-based hot melt adhesive applied in a dot matrix pattern, the hot melt adhesive having a melting point of 46°C and an adjacent dot matrix spacing of 35 millimeters.

[0011] Product Specifications: Standard width: 160×220 cm (general type); 90×180 cm (operating table type); 120×200 cm (ward type). Overall weight: Approximately 95 g / m². Packaging: Roll or folded individual packaging. Color: White The performance test results of the product in this embodiment are as follows: (1) Urine tolerance test: The product was dripped with simulated urine at 37°C and continuously contacted for 24 hours. The three-layer structure remained intact, with no leakage or disintegration, and was deemed qualified. (2) Disintegration trigger test: The product was immersed in hot water at 42±1°C. Within 3 minutes, all the lattice bonding points failed, the three layers separated, and the product was broken into fiber and paper fragments with a diameter of no more than 2 cm, and was deemed qualified. (3) Impermeability test: The hydrostatic pressure test was conducted. The hydrostatic pressure was measured to be no less than 15 cm water column, and the impermeability was qualified, and was deemed qualified. (4) Fragment degradation test: The disintegrated fragments were placed in the activated sludge environment of a sewage treatment plant for 48 hours. The cellulose degradation rate was greater than 88%, and the paper base degradation rate was greater than 85%, and was deemed qualified. (5) Chemical Oxygen Demand (COD) Contribution Test: One bed sheet was dissolved in 50 liters of water, and the COD value was measured to be 420 mg / L, which meets the GB 8978 Class III emission standard and is deemed qualified. (6) Comparison of Disposal Costs: Using the hospital hot water treatment method, the disposal cost per sheet is less than 0.5 yuan; while using the special medical waste disposal method, the cost is 3 to 8 yuan per sheet. The present invention significantly reduces the disposal cost and is deemed to have a significant economic advantage.

[0012] Example 4: Heat-triggered dissolving disposable hospital gown Raw materials and formula The materials and specifications of each component of the heat-triggered dissolving disposable hospital gown are as follows: The body fabric is made of viscose spunbond nonwoven fabric with a weight of 45 grams per square meter, which is soft and breathable; the seams of the cut pieces are formed by ultrasonic welding with biodegradable polyester-based hot melt adhesive, and the hot melt adhesive has a melting point of 44°C; the fasteners are paper buttons or paper ties made of kraft paper, which soften and break within 30 seconds after being exposed to hot water; the labels are water-soluble paper labels to ensure the integrity of the printed information; the product style is a V-neck pullover, and each gown consists of 4 cut pieces.

[0013] This product is available in four sizes: S, M, L, and XL. Size S has a chest circumference of 90 cm and a length of 65 cm, suitable for heights ranging from 150 to 160 cm; Size M has a chest circumference of 100 cm and a length of 70 cm, suitable for heights ranging from 160 to 170 cm; Size L has a chest circumference of 110 cm and a length of 75 cm, suitable for heights ranging from 170 to 180 cm; and Size XL has a chest circumference of 120 cm and a length of 80 cm, suitable for heights ranging from 180 to 190 cm.

[0014] The performance test results of the product in this embodiment are as follows: (1) Urine tolerance test: The product was exposed to simulated urine at 37°C for 24 hours. The weld remained intact, without cracking, and the structure was stable. The product was deemed qualified. (2) Disintegration trigger test: The product was immersed in hot water at 42±1°C. Within 3 minutes, all welds failed, each piece separated, and the adhesive fabric broke into fiber fragments with a diameter of no more than 2 cm. The product was deemed qualified. (3) Fragment degradation test: The disintegrated fragments were placed in the activated sludge environment of a sewage treatment plant for 48 hours. The degradation rate was greater than 90%, and there was no microplastic residue. The product met the GB / T 41244-2022 standard. The product was deemed qualified. (4) Comparison of disposal costs: The disposal cost per item was less than RMB1 when using the hospital hot water treatment method; while the cost per item was RMB10 to RMB20 when using the special disposal method for medical waste. The present invention significantly reduces the disposal cost and has a significant economic advantage.

[0015] Example 5: Comparative Test – Urine Tolerance Verification (24 hours) Urine tolerance was tested on the products of Examples 1 to 4. The comparison samples were traditional products using PP / PE skeleton material and washable products using only ordinary hot melt adhesive (melting point 80°C). The test results of each sample after soaking in artificial urine at 37°C for 24 hours are as follows: The product of this invention (using modified starch hot melt adhesive with a melting point of 42 to 50°C, combined with a viscose fiber skeleton) showed structural integrity, no disintegration, and a bond strength retention rate of over 95% in testing. Traditional polypropylene / polyethylene (PP / PE) products (using hot melt adhesive with a melting point of 80°C) showed structural integrity, but due to the presence of microplastics, the disintegration fragments did not meet emission regulations. Ordinary flushable products (using PP nonwoven fabric combined with ordinary hot melt adhesive) showed structural integrity, but the disintegration fragments were PP microplastics, which did not meet the requirements of GB / T 41244-2022 standard. The above comparative tests demonstrate that the product of this invention is comparable to traditional products in terms of urine tolerance, while possessing significant advantages in biodegradability and compliance that traditional products cannot achieve.

[0016] Beneficial effects (1) Environmental compliance: All skeleton materials are biodegradable, and the disintegration products have no microplastic residues, which meets the GB / T 41244-2022 flushable standard. (2) Zero waste treatment in medical institutions: Disposable bed sheets and hospital gowns can be directly put into the hot water bucket in the ward after use and disintegrate without the need for special collection and transportation of medical waste, which greatly reduces the disposal cost (estimated disposal cost per item is reduced from RMB 8 to RMB 20 to RMB 0.5 to RMB 1.0). (3) High safety in urine environment: After soaking in urine at no more than 40°C for 24 hours, the product structure remains intact and unchanged, ensuring that it will not be accidentally disintegrated due to urine temperature or body temperature during use, and has high reliability. (4) Fast and controllable hot water disintegration: After being triggered by hot water at no less than 42°C, it completely disintegrates into fragments with a diameter of no more than 2 cm within 3 minutes, with high processing efficiency, which is suitable for batch processing scenarios in hospitals. (5) Safety in use: 42°C hot water is an acceptable temperature for the human body (slightly higher than bath water temperature), which will not cause scalding and is below the skin scalding threshold (there is a risk only if there is continuous contact above 45°C). (6) High reusability of the technology platform: The heat-sensitive adhesive system is applicable to four types of products: adult diapers, children's diapers, bed sheets, and hospital gowns. The R&D cost is low and the industrialization speed is fast. (7) Controllable cost: Using viscose fiber (a mature industrial variety), starch-based SAP (there are already many domestic suppliers) and modified starch hot melt adhesive (mature process), the overall cost premium is about 1.5 to 1.8 times, which is significantly advantageous compared to the all-PVA solution (3 to 4 times premium). (8) High industrial feasibility: Viscose nonwoven fabric, spunlace process, starch-based SAP, and hot melt adhesive composite process are all existing mature technologies. There is no need to build a new production line. It can be put into production after technical transformation on the existing disposable hygiene product production line. (9) Discharge compliance: The disintegration products can be biodegraded within 48 hours after entering the sewage treatment plant through the urban sewage pipe network. The COD contribution meets the GB 8978 Class III discharge standard and does not increase the treatment burden of the sewage treatment plant. Attached Figure Description Figure 1 : Schematic diagram of the cross-sectional structure of the multi-layer material in a heat-triggered dissolving diaper. Figure 2 : Schematic diagram of the overall structure of the heat-triggered dissolution type patient gown. Figure 3 : Schematic diagram of the weld structure of the heat-triggered dissolution type patient gown cut piece. Figure 4 : This is a schematic diagram of the hot water disintegration treatment process. Figure 5 : This is a curve comparing the adhesive strength of heat-sensitive adhesives (Adhesive Strength vs Temperature Comparison). Figure 6 : A schematic diagram of the overall structure of adult / children's diapers.

Claims

1. A heat-triggered dissolving disposable sanitary product, characterized in that: The sanitary products, when in use and in contact with urine or bodily fluids at ≤40°C, maintain their structural integrity and do not disintegrate, soften, or fail to adhere within 24 hours; when immersed in hot water at ≥42°C, they completely disintegrate into fragments with a maximum diameter of no more than 2 cm within 3 minutes; the disintegrated fragments undergo complete biodegradation within 48 hours during subsequent urban sewage pipeline transportation and sewage treatment, without producing microplastic residues; the sanitary products include: adult diapers, children's diapers, disposable bed sheets, and disposable hospital gowns; the layers of the sanitary products are bonded together using a heat-sensitive adhesive with a melting or softening point of 42 to 50°C; all the skeleton materials of the sanitary products are biodegradable materials, including at least one of regenerated cellulose fiber nonwoven fabric, starch-based superabsorbent resin, and paper-based geomembrane; The hygiene products do not contain one or more non-degradable synthetic plastics such as polypropylene, polyethylene, and polyethylene terephthalate.

2. The heat-triggered dissolving disposable sanitary product according to claim 1, characterized in that: The heat-sensitive adhesive is a modified starch-based hot melt adhesive or a biodegradable polyester-based hot melt adhesive, with a melting point or softening point of 42 to 50°C. It completely melts and fails in hot water at ≥42°C, and after failure, the adhesive strength is reduced to less than 5% of the initial value.

3. The heat-triggered dissolving disposable sanitary product according to claim 1, characterized in that: The regenerated cellulose fiber nonwoven fabric is viscose fiber nonwoven fabric or lyocell fiber nonwoven fabric, with a basis weight of 15 to 80 g / m², which meets the washability requirements of GB / T41244-2022 "Washable Spunlace Nonwoven Materials and Products".

4. The heat-triggered dissolving disposable sanitary product according to claim 1, characterized in that: The starch-based superabsorbent resin is obtained by graft polymerization of starch and acrylic acid, with a water absorption ratio of 50 to 200 times, a particle size of 0.1 to 1.0 mm, and can be dispersed and dissolved in hot water at ≥42°C, while maintaining gel stability in an environment at ≤40°C.

5. The heat-triggered dissolving disposable sanitary product according to claim 1, characterized in that: The paper-based geomembrane uses wet-strength paper as the substrate, with a single-sided or double-sided composite biodegradable polymer coating, and a total basis weight of 30 to 80 g / m². In hot water at ≥42°C, the paper base softens and tears, and the biodegradable coating disintegrates simultaneously.

6. The disposable hygiene product according to claim 1 is an adult diaper or a children's diaper, characterized in that, Including those stacked from top to bottom: Skin-friendly surface layer: viscose fiber hot-air nonwoven fabric or perforated viscose nonwoven fabric, weight 18 to 30 g / m²; Dispersion and flow guiding layer: viscose fiber hot air nonwoven fabric, basis weight 25 to 45 g / m²; Absorbent core layer: a mixture of viscose fiber fluff pulp and starch-based superabsorbent polymer (SAP), with a thickness of 4 to 10 mm, a starch-based SAP content of 40 to 70 wt%, and an absorbency of not less than 300 g (adult) or not less than 200 g (child). Impermeable bottom layer: paper-based breathable composite membrane, basis weight 35 to 60 g / m²; Outer layer wrapped with non-woven fabric: viscose spunbond non-woven fabric, weight 15 to 25 g / m²; Waist support and elastic waistband: Viscose fiber-based elastic composite material, bonded by modified starch-based hot melt adhesive; Interlayer adhesion: Modified starch-based hot melt adhesive, melting point 42 to 48°C, coating amount 8 to 15 g / m².

7. The diaper according to claim 6, characterized in that: The adult diaper's waistband fasteners are made of paper-based hook and loop fasteners or water-soluble adhesive strips. The fasteners will fail and fall off first in hot water at ≥42°C. The children's diaper's elastic waistband is made of heat-sensitive adhesive-bonded viscose fiber elastic strips with an elastic elongation of 80% to 120%.

8. The disposable sanitary product according to claim 1 is a disposable bed sheet, characterized in that: The disposable bed sheet has a three-layer composite structure, including an upper surface layer, a waterproof layer in the middle, and a lower surface layer; Top layer: viscose spunbond nonwoven fabric, weight 25 to 40 g / m²; Geomembrane: Wet-strength paper-based composite geomembrane, basis weight 20 to 40 g / m²; Bottom layer: viscose spunbond nonwoven fabric, weight 20 to 35 g / m²; Interlayer bonding: Modified starch-based hot melt adhesive is compounded in a dot matrix manner with a dot matrix spacing of 15 to 40 mm and a melting point of 44 to 48°C; Overall weight: 65 to 120 g / m², width adjustable from 90 to 220 cm.

9. The disposable bed sheet according to claim 8, characterized in that: The disposable bed sheet loses its bonding points sequentially within 3 minutes in hot water at ≥42°C, and the three-layer structure completely separates; the bed sheet is broken into fiber and paper-based fragments with a diameter of ≤2 cm, and the fragments have a biodegradation rate of not less than 90% within 48 hours in the activated sludge environment of the sewage treatment plant.

10. The disposable hygiene product according to claim 1 is a disposable hospital gown, characterized in that: The patient gown is made of viscose spunbond nonwoven fabric or spunlace nonwoven fabric with a weight of 30 to 60 g / m². The garment pieces are joined together by ultrasonic welding, with the welding material being biodegradable polyester-based hot melt adhesive with a melting point of 42 to 48°C. Fasteners or ties are made of paper or starch-based paper. The product label is a water-soluble paper label. The welds fail within 3 minutes in hot water at ≥42°C, causing the garment pieces to separate and the nonwoven fabric to break into fiber fragments with a diameter of ≤2 cm.

11. The disposable hospital gown according to claim 10, characterized in that: The hospital gowns are designed with a round neck and open front, and come in sizes from S to XL. The number of fabric pieces is controlled within the range of 4 to 6 to reduce the number of welds and optimize the hot water disintegration efficiency. The fabric color is white or light blue.

12. The disposable sanitary product according to any one of claims 1 to 11, characterized in that: The outer packaging of the hygiene products is made of biodegradable film material and is subjected to hot water disintegration treatment after the product is used.

13. The disposable sanitary product according to any one of claims 1 to 11, characterized in that: The hygiene products mentioned herein are free of fluorescent whitening agents, free formaldehyde, and decomposable carcinogenic aromatic amine dyes. The content of heavy metals and harmful chemicals complies with the requirements of GB15979 "Hygienic Standard for Disposable Hygiene Products".

14. A method for preparing the heat-triggered dissolving disposable sanitary product according to claims 1 to 13, characterized in that, Includes the following steps: (1) Preparation of washable nonwoven fabric layer: After opening, carding and web laying of viscose short fibers or lyocell fibers, nonwoven fabric with a basis weight of 15 to 80 g / m² is prepared by hydroentangling or hot rolling process; the obtained nonwoven fabric meets the washability requirements of GB / T 41244-2022. (2) Preparation of starch-based superabsorbent polymer: starch and acrylic acid are grafted and polymerized under the action of a redox initiator to obtain starch-polyacrylic acid graft copolymer. After saponification, washing, drying and pulverization, starch-based SAP is obtained. It can disperse and dissolve in hot water at ≥42°C, with a water absorption ratio of 50 to 200 times; (3) Preparation of paper-based geomembrane: Using wet-strength paper as the substrate, a biodegradable polyester or PLA coating is applied by extrusion coating to obtain a paper-based geomembrane with a basis weight of 30 to 80 g / m². (4) Preparation of heat-sensitive adhesive: Modified starch or biodegradable polyester resin is compounded with plasticizer and tackifier, and the softening point is adjusted to the range of 42 to 50°C to prepare heat-sensitive adhesive; (5) Assembly molding: The materials of each layer are stacked according to the product structure, and the interlayer dot matrix bonding or full bonding is achieved by using a heat-sensitive adhesive at 80 to 110°C. After molding, it is cut into finished products.

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