A high-impermeability, dispersible, and leak-proof layer and its preparation method and application

Abstract

The present invention relates to the field of disposable absorbent sanitary products, and in particular to a highly impermeable and flushable leak-proof layer and its preparation method and application. The highly impermeable and flushable leak-proof layer includes a high-temperature water-soluble film layer and a heating layer; the lower surface of the high-temperature water-soluble film layer is in contact with the upper surface of the heating layer; the dissolution temperature of the high-temperature water-soluble film layer is ≥38°C; the heating layer includes a heating material, and the heating material has the characteristic of releasing heat when in contact with water. The leak-proof layer of the present invention adopts a double-layer matching structure of a high-temperature water-soluble film layer and a heating layer, which can ensure the overall flushability of the leak-proof layer while ensuring that the leak-proof layer will not be wetted and softened, or even partially develop holes or cracks after contacting menstrual blood, urine or sweat during use, thereby ensuring that the leak-proof layer will not have the risk of liquid leakage when in use.

Description

Technical Field

[0001] The invention relates to the field of disposable absorbent sanitary products, and in particular to a highly impermeable and flushable anti-leakage layer and a preparation method and application thereof. Background Art

[0002] At present, nonwoven materials are widely used in disposable absorbent articles, including baby diapers, women's care products (sanitary napkins, pads, etc.), and adult incontinence products. These disposable products are usually composed of a surface layer, an absorbent layer, and a leakproof layer, wherein the leakproof layer is usually made of a water-impermeable material, such as polypropylene or polyethylene film, to ensure that liquid does not leak from the bottom during use. However, the above-mentioned film material is a polymer synthetic material, the product is not recyclable, and cannot be naturally degraded after being discarded, which has become a new white pollution.

[0003] In response to the concept of green and sustainable development, the industry is now actively developing flushable absorbent products that can maintain their shape and strength during use. After use, the entire absorbent product can be hydrolyzed and dispersed, and can be directly flushed down the toilet. At present, the research on the surface layer and absorption layer of flushable absorbent products is relatively mature. Generally, wet-laid spunlace nonwoven fabrics can be used as flushable surface layers. Cellulose fibers are often used as raw materials. Cellulose fibers have high liquid permeability and biodegradability, low wet strength, and can be dispersed in water. Loose fluff pulp or cellulose fibers and highly absorbent powders are often used to form a flushable absorbent layer to lock in liquid. The loose fiber bundles have low entanglement force and are easy to disperse in water. The difficulty in the research lies in the leak-proof layer, which must not only ensure that it can block liquid leakage during use and be water-repellent, but also take into account water dispersibility after use.

[0004] There are studies that use normal temperature water-soluble films (such as the polyvinyl alcohol film that can be dissolved and dispersed at 25°C in patent CN113395952A) as a leak-proof layer, which can take into account both liquid isolation and water dispersibility. Normal temperature water-soluble films can block liquid leakage, and because they have strong water solubility, they can be dispersed and dissolved when thrown into a toilet. However, there are some shortcomings in actual use: normal temperature water-soluble films can be dissolved in normal temperature water. When they are used for a long time or when sweating a lot, the normal temperature water-soluble films will contact a large amount of liquid and moisture, causing the normal temperature water-soluble films to absorb liquid and water vapor, with a strong sense of moisture, and are prone to premature softening and dissolution of the film, and even local holes and cracks will appear, directly leading to liquid leakage and contamination of clothing.

[0005] In view of the above-mentioned problems existing in the prior art, it is necessary to develop a highly impermeable and flushable anti-leakage layer with sustained and stable anti-leakage effect, especially safe and reliable during the use of the product, without material decomposition, and the product can be directly thrown into the toilet and flushed after use without affecting the drainage system. Summary of the invention

[0006] In order to solve the technical problems in the prior art that the anti-leakage layer of flushable absorbent sanitary products has poor liquid barrier durability and is prone to premature decomposition, the present invention provides a highly impermeable flushable anti-leakage layer and a preparation method and application thereof. The highly impermeable flushable anti-leakage layer has good liquid barrier durability during use and can be flushed as a whole when thrown into the toilet after use.

[0007] The specific technical scheme of the present invention is:

[0008] In the first aspect, the present invention provides a highly impermeable and flushable leak-proof layer, comprising a high-temperature water-soluble film layer and a heating layer; the lower surface of the high-temperature water-soluble film layer is bonded to the upper surface of the heating layer; the dissolution temperature of the high-temperature water-soluble film layer is ≥38°C; the heating layer comprises a heating material, and the heating material has the property of releasing heat when in contact with water.

[0009] The leakproof layer of the present invention adopts a double-layer structure of a high-temperature water-soluble film layer and a heating layer, which can ensure the overall flushability of the leakproof layer while making it have good liquid-isolating durability during use. Specifically: the present invention adopts a high-temperature water-soluble film as a liquid-isolating barrier, which can only be dispersed and dissolved in water at 38°C or above. In actual use, the temperature of the absorbed human menstrual blood, urine or sweat generally does not exceed 38°C, which can ensure that the absorbed liquid will not cause the film to be moistened and softened or even partially form holes and cracks when it contacts the film, thereby ensuring that the leakproof layer can be leak-proof for a long time during use. In addition, the present invention sets a heating layer on the lower surface of the high-temperature water-soluble film layer, and the heating material therein can be used as a heating source. When thrown into the toilet after use, the heating material releases heat when it meets water, causing the water to heat up, thereby causing the high-temperature water-soluble film layer to disperse and dissolve in the water. In addition, when in use, the heating layer is located below the high-temperature water-soluble film layer. Due to the barrier of the latter, the heating material in the heating layer will not contact menstrual blood, urine or sweat to release heat, thereby preventing the high-temperature water-soluble film layer from being damaged prematurely during use.

[0010] Preferably, the highly impermeable and dispersible leak-proof layer further comprises a layer of water-dispersible material at room temperature; the upper surface of the layer of water-dispersible material at room temperature is in contact with the lower surface of the heating layer.

[0011] The room temperature water dispersible material layer is arranged below the heating layer, which can play the following role: during use, the room temperature water dispersible material layer can prevent external moisture or water from contacting the heating material, thereby preventing the heating material from prematurely releasing heat and failing, thereby ensuring that the high temperature water-soluble film layer will not be damaged during use, and can be quickly flushed away after use. Moreover, when thrown into the toilet after use, the room temperature water dispersible material layer can be flushed away by water, so that the heating material contacts the water, thereby achieving the overall dispersion of the leak-proof layer.

[0012] Furthermore, the room temperature water-dispersible material layer is a room temperature water-soluble film or a dispersible fiber material; the dissolution temperature of the room temperature water-soluble film is ≤25°C.

[0013] Furthermore, the flushable fiber material is composed of fibers entangled with each other.

[0014] Furthermore, the fibers in the flushable fiber material are degradable fibers.

[0015] Preferably, the heating material is one or more combinations of iron powder, aluminum powder, activated carbon, diatomaceous earth, sodium chloride, quicklime and sodium carbonate.

[0016] Preferably, the heat-generating material is a heat-generating microcapsule; the wall material of the heat-generating microcapsule is a water-soluble film at room temperature; and the core of the heat-generating microcapsule is a material that releases heat when in contact with water.

[0017] The present invention designs the heat-generating material into a microcapsule form. During use, the wall material (normal temperature water-soluble film) can play a liquid barrier role, preventing external moisture or water from contacting the core (water-exothermic material), avoiding the water-exothermic material from releasing heat too early during use, thereby further improving the leakage-proof durability and overall flushability of the leak-proof layer. In addition, when thrown into the toilet after use, the normal temperature water-soluble film can quickly disperse and dissolve in water, allowing the water-exothermic material to contact water, thereby achieving overall dispersion of the leak-proof layer.

[0018] Furthermore, the particle size of the heat-generating microcapsules is 50-100 meshes, wherein the mass ratio of the wall material to the core is 2:8-8:2.

[0019] The use of an appropriate mass ratio of wall material to core can realize the decentralized heating process of the sewer. If the wall material content is too high and the heating core content is too low, the high-temperature water-soluble film layer will not be able to quickly and continuously heat up to the film breaking and melting, resulting in a failure of dispersion and easy clogging of the toilet.

[0020] Furthermore, the dissolution temperature of the room temperature water-soluble film is ≤25°C.

[0021] Furthermore, the core of the heat-generating microcapsule is one or more combinations of iron powder, aluminum powder, activated carbon, diatomaceous earth, sodium chloride, quicklime and sodium carbonate.

[0022] Furthermore, in the high impermeability and dispersible leak-proof layer, the amount of the heat-generating material added is 5 to 15 g / m 2 .

[0023] Preferably, the high temperature water-soluble film layer has a thickness of 50 to 200 μm.

[0024] The research team of the present invention has noticed that as the thickness of the high-temperature water-soluble film layer increases, its tensile strength increases, which can better prevent local leakage of the film after it is slightly wetted during use. However, at the same time, the increase in the thickness of the high-temperature water-soluble film layer will also affect its dispersion and dissolution speed under the action of the heating layer, making the flushability of the leak-proof layer after being thrown into the toilet decrease. Based on this, the present invention sets the thickness of the high-temperature water-soluble film layer to 50-200 μm, which can better balance the liquid barrier durability and overall flushability of the leak-proof layer.

[0025] Preferably, the high-temperature water-soluble film layer is a water-soluble polyvinyl alcohol film.

[0026] In a second aspect, the present invention provides a method for preparing the highly impermeable and flushable leak-proof layer, comprising the following steps: making a heating material into a heating layer and fixing it under a high-temperature water-soluble film to form a highly impermeable and flushable leak-proof layer.

[0027] In a third aspect, the present invention provides a flushable absorbent sanitary product, comprising the high-impermeability flushable anti-leakage layer.

[0028] Preferably, a dispersible absorption layer is provided above the high-impermeability dispersible leakage-proof layer, and the upper surface of the high-temperature water-soluble film layer is in contact with the lower surface of the dispersible absorption layer; a dispersible surface layer is provided above the dispersible absorption layer.

[0029] Furthermore, the periphery of the dispersible surface layer is connected to the periphery of the high-impermeability dispersible anti-leakage layer; the periphery of the dispersible absorption layer is covered and fixed by the dispersible surface layer and the high-impermeability dispersible anti-leakage layer.

[0030] Furthermore, a dispersible bottom layer is provided below the highly impermeable and dispersible anti-leakage layer.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] (1) The leak-proof layer of the present invention adopts a double-layer structure of a high-temperature water-soluble film layer and a heat-generating layer, which can ensure the overall flushability of the leak-proof layer. When the leak-proof layer comes into contact with menstrual blood, urine or sweat during use, the leak-proof layer will not be wetted and softened, or even partially develop holes or cracks, thereby ensuring that there is no risk of liquid leakage in the leak-proof layer during use;

[0033] (2) In the leak-proof layer of the present invention, by arranging a room temperature water-dispersible material layer below the heating layer and / or designing the heating material into a microcapsule form, the heating action time of the heating layer can be accurately controlled so that it will generate heat only when thrown into the toilet, thereby further improving the liquid barrier durability and overall flushability of the leak-proof layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1Schematic diagram of the cross-sectional structure of the anti-leakage layer of Example 1;

[0035] Figure 2 Schematic diagram of the cross-sectional structure of the anti-leakage layer of Example 2;

[0036] Figure 3 The cross-sectional structure diagram of the anti-leakage layer of Example 3;

[0037] Figure 4 is a schematic diagram of the cross-sectional structure of the anti-leakage layer of Example 4;

[0038] Figure 5 The present invention is a schematic diagram of a cross-sectional structure of a flushable absorbent sanitary product.

[0039] The accompanying drawings are marked as: high-temperature water-soluble film layer 1, heat-generating layer 2, normal-temperature water-dispersible material layer 3, flushable surface layer 4, flushable absorption layer 5, flushable leak-proof layer 6, and flushable bottom layer 7. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the embodiments.

[0041] Overall embodiment

[0042] A highly impermeable and diffusible leakproof layer, such as Figures 1 to 4 As shown, it includes a high-temperature water-soluble film layer 1 and a heating layer 2; the lower surface of the high-temperature water-soluble film layer 1 is bonded to the upper surface of the heating layer 2; the dissolution temperature of the high-temperature water-soluble film layer 1 is ≥38°C; the heating layer 2 includes a heating material, and the heating material has the characteristic of releasing heat when in contact with water.

[0043] As a specific implementation method, Figures 2 to 4 As shown, the high impermeability and dispersible leak-proof layer also includes a room temperature water-dispersible material layer 3; the upper surface of the room temperature water-dispersible material layer 3 is in contact with the lower surface of the heat-generating layer 2.

[0044] In the above specific embodiment: Optionally, the room temperature water dispersible material layer 3 is a room temperature water soluble film or a flushable fiber material; the dissolution temperature of the room temperature water soluble film is ≤25° C. Optionally, the flushable fiber material is composed of fibers entangled with each other, and the fibers in the flushable fiber material are degradable fibers, further cellulose fibers.

[0045] As a specific implementation, the heating material is one or more combinations of iron powder, aluminum powder, activated carbon, diatomaceous earth, sodium chloride, quicklime and sodium carbonate.

[0046] As another specific implementation, the heat-generating material is a heat-generating microcapsule; the wall material of the heat-generating microcapsule is a water-soluble film at room temperature; and the core of the heat-generating microcapsule is a material that releases heat when in contact with water.

[0047] In the above specific implementation: Optionally, the particle size of the heat-generating microcapsule is 50-100 mesh, wherein the mass ratio of the wall material to the core is 2:8-8:2. Optionally, the dissolution temperature of the room temperature water-soluble film is ≤25°C. Optionally, the core of the heat-generating microcapsule is one or more combinations of iron powder, aluminum powder, activated carbon, diatomaceous earth, sodium chloride, quicklime and sodium carbonate.

[0048] As a specific implementation method, the amount of the heat-generating material added to the high-impermeability and dispersible leak-proof layer is 5 to 15 g / m 2 .

[0049] As a specific implementation, the thickness of the high temperature water-soluble film layer 1 is 50-200 μm.

[0050] As a specific implementation, the high-temperature water-soluble film layer 1 is a water-soluble polyvinyl alcohol film.

[0051] A method for preparing the above-mentioned high-impermeability and flushable leak-proof layer includes the following steps: making a heating material into a heating layer and fixing it under a high-temperature water-soluble film to make a high-impermeability and flushable leak-proof layer.

[0052] As a specific implementation, the preparation method specifically comprises the following steps:

[0053] S1: bonding the heat-generating materials together to form a whole to obtain a heat-generating layer;

[0054] S2: Fix the heating layer under the high-temperature water-soluble film to form a highly impermeable and flushable anti-leakage layer.

[0055] As another specific implementation, the preparation method specifically includes the following steps: uniformly fixing the heating material to one side surface of the high-temperature water-soluble film to form a heating layer, thereby obtaining a highly impermeable and flushable anti-leakage layer.

[0056] As another specific implementation, the preparation method specifically comprises the following steps:

[0057] S1: evenly placing the heat-generating material on the room temperature water dispersion material layer to form a heat-generating layer;

[0058] S2: Bonding the normal temperature water dispersible material layer and the high temperature water soluble film layer up and down, and wrapping the heating layer between the two, to form a highly impermeable and flushable anti-leakage layer.

[0059] As a specific implementation, the heating layer is fixed to the bottom of the high-temperature water-soluble film by bonding or ultrasonic bonding.

[0060] A flushable absorbent sanitary product comprises the above-mentioned high impermeability flushable leak-proof layer 6.

[0061] As a specific implementation method, Figure 5 As shown, a dispersible absorption layer 5 is provided above the high-impermeability dispersible leakage-proof layer 6, and the upper surface of the high-temperature water-soluble film layer 1 is in contact with the lower surface of the dispersible absorption layer 5; a dispersible surface layer 4 is provided above the dispersible absorption layer 5; the periphery of the dispersible surface layer 4 is connected to the periphery of the high-impermeability dispersible leakage-proof layer 6; the dispersible absorption layer 5 is covered and fixed by the dispersible surface layer 4 and the high-impermeability dispersible leakage-proof layer 6 on all sides; a dispersible bottom layer 7 is provided below the high-impermeability dispersible leakage-proof layer 6.

[0062] Example 1

[0063] A highly impermeable and diffusible leakproof layer, such as Figure 1 As shown, from top to bottom, it is composed of a high-temperature water-soluble film layer 1 and a heating layer 2, and the heating layer 2 is bonded to the lower surface of the high-temperature water-soluble film layer 1. Among them, the high-temperature water-soluble film layer 1 is a high-temperature water-soluble polyvinyl alcohol film, whose dissolution temperature is 40°C and the film thickness is 200μm. The heating layer 2 is a mixture of three heating materials, quicklime powder, sodium carbonate powder and diatomaceous earth, with a mass ratio of 3:1:1. The total addition amount of the three heating materials is 5g / m 2 .

[0064] The above-mentioned leak-proof layer is prepared by the following steps: one side of the high-temperature water-soluble polyvinyl alcohol film is coated with glue, the heating material (a mixture of quicklime powder, sodium carbonate powder, and diatomaceous earth) is bonded to the glue-coated surface of the high-temperature water-soluble polyvinyl alcohol film to form a heating layer, and the heating layer is pressed with a pressure roller to form a highly impermeable and flushable leak-proof layer.

[0065] A flushable absorbent sanitary product, such as Figure 5 As shown, it is composed of a dispersible surface layer 4, a dispersible absorption layer 5, a high-impermeability dispersible anti-leakage layer 6, and a dispersible bottom layer 7 which are sequentially overlapped and connected from top to bottom. The upper surface of the high-temperature water-soluble film layer 1 is bonded to the lower surface of the dispersible absorption layer 5, and the lower surface of the heating layer 2 is bonded to the upper surface of the dispersible bottom layer 7. The periphery of the dispersible surface layer 4 is connected to the periphery of the high-impermeability dispersible anti-leakage layer 6, and the four sides of the dispersible absorption layer 5 are covered and fixed by the dispersible surface layer 4 and the high-impermeability dispersible anti-leakage layer 6.

[0066] Example 2

[0067] A highly impermeable and diffusible leakproof layer, such as Figure 2As shown, from top to bottom, it is composed of a high-temperature water-soluble film layer 1, a heating layer 2, and a room-temperature water-dispersible material layer 3. Among them, the high-temperature water-soluble film layer 1 is a high-temperature water-soluble polyvinyl alcohol film A, whose dissolution temperature is 50°C and the film thickness is 100μm. The heating layer 2 is a mixture of four heating materials, quicklime powder, sodium carbonate powder, activated carbon powder and iron powder, with a mass ratio of 2:1:1:1. The total addition amount of the four heating materials is 10g / m 2 The room temperature water dispersible material layer 3 is a water-soluble polyvinyl alcohol film B, whose dissolution temperature is 25° C. The high temperature water-soluble polyvinyl alcohol film A and the water-soluble polyvinyl alcohol film B are connected up and down to cover and fix the heat-generating material.

[0068] The above-mentioned leak-proof layer is prepared by the following steps: the heating material (a mixture of quicklime powder, sodium carbonate powder, activated carbon powder and iron powder) is evenly sprinkled on the upper surface of the water-soluble polyvinyl alcohol film B to form a heating layer, and the water-soluble polyvinyl alcohol film B and the high-temperature water-soluble polyvinyl alcohol film A are bonded and connected up and down to cover and fix the heating material to form a highly impermeable and flushable leak-proof layer.

[0069] A dispersible absorbent sanitary product, comprising a dispersible surface layer 4, a dispersible absorbent layer 5, a high-impermeability dispersible leakproof layer 6, and a dispersible bottom layer 7, which are sequentially overlapped and connected from top to bottom. The upper surface of the high-temperature water-soluble film layer 1 is bonded to the lower surface of the dispersible absorbent layer 5, and the lower surface of the normal-temperature water-dispersible material layer 3 is bonded to the upper surface of the dispersible bottom layer 7. The periphery of the dispersible surface layer 4 is connected to the periphery of the high-impermeability dispersible leakproof layer 6, and the periphery of the dispersible absorbent layer 5 is covered and fixed by the dispersible surface layer 4 and the high-impermeability dispersible leakproof layer 6.

[0070] Example 3

[0071] A highly impermeable and diffusible leakproof layer, such as Figure 3 As shown, from top to bottom, it is composed of a high-temperature water-soluble film layer 1, a heating layer 2, and a room-temperature water-dispersible material layer 3. Among them, the high-temperature water-soluble film layer 1 is a high-temperature water-soluble polyvinyl alcohol film with a dissolution temperature of 70°C and a film thickness of 50μm. The heating layer 2 is a mixture of five heating materials, quicklime powder, sodium carbonate powder, activated carbon powder, iron powder, and sodium chloride powder, in a mass ratio of 3:1:2:1:1. The total addition amount of the five heating materials is 15g / m 2 The room temperature water dispersible material layer 3 is a dispersible fiber material, which is composed of 40% by mass of viscose fiber and 60% by mass of wood pulp fiber. The heating material is located between the dispersible fiber material and the water-soluble polyvinyl alcohol film.

[0072] The above-mentioned leak-proof layer is prepared by the following steps: the heating material (a mixture of quicklime powder, sodium carbonate powder, activated carbon powder and iron powder) is evenly sprinkled on the upper surface of the flushable fiber material (made of 40% viscose fiber and 60% wood pulp fiber entangled by wet hydroentanglement by a mass percentage) to form a heating layer, and the heating layer is bonded to the high-temperature water-soluble polyvinyl alcohol film from top to bottom to form a highly impermeable flushable leak-proof layer.

[0073] A dispersible absorbent sanitary product, comprising a dispersible surface layer 4, a dispersible absorbent layer 5, a high-impermeability dispersible leakproof layer 6, and a dispersible bottom layer 7, which are sequentially overlapped and connected from top to bottom. The upper surface of the high-temperature water-soluble film layer 1 is bonded to the lower surface of the dispersible absorbent layer 5, and the lower surface of the normal-temperature water-dispersible material layer 3 is bonded to the upper surface of the dispersible bottom layer 7. The periphery of the dispersible surface layer 4 is connected to the periphery of the high-impermeability dispersible leakproof layer 6, and the periphery of the dispersible absorbent layer 5 is covered and fixed by the dispersible surface layer 4 and the high-impermeability dispersible leakproof layer 6.

[0074] Example 4

[0075] A highly impermeable and diffusible leakproof layer, such as Figure 4 As shown, from top to bottom, it is composed of a high-temperature water-soluble film layer 1, a heating layer 2, and a room-temperature water-dispersible material layer 3. Among them, the high-temperature water-soluble film layer 1 is a high-temperature water-soluble polyvinyl alcohol film A, which has a dissolution temperature of 50°C and a film thickness of 100μm. The heating layer 2 is a heating microcapsule with a particle size of 50 to 60 mesh; the wall material of the heating microcapsule is a water-soluble polyvinyl alcohol film C (dissolution temperature is 25°C), the core is quicklime, and the mass ratio of the wall material to the core is 2:8; the addition amount of the heating microcapsule is 10g / m 2 The room temperature water dispersible material layer 3 is a water-soluble polyvinyl alcohol film B, whose dissolution temperature is 25° C. The high temperature water-soluble polyvinyl alcohol film A and the water-soluble polyvinyl alcohol film B are connected up and down to cover and fix the heat-generating material.

[0076] The above-mentioned leak-proof layer is prepared by the following steps: the core (quicklime) and the wall material (water-soluble polyvinyl alcohol) are made into heat-generating microcapsules, the heat-generating microcapsules are evenly sprinkled on the upper surface of the water-soluble polyvinyl alcohol film B to form a heat-generating layer, the water-soluble polyvinyl alcohol film B and the high-temperature water-soluble polyvinyl alcohol film A are bonded together to cover and fix the heat-generating microcapsules to form a highly impermeable and flushable leak-proof layer.

[0077] A dispersible absorbent sanitary product, comprising a dispersible surface layer 4, a dispersible absorbent layer 5, a high-impermeability dispersible leakproof layer 6, and a dispersible bottom layer 7, which are sequentially overlapped and connected from top to bottom. The upper surface of the high-temperature water-soluble film layer 1 is bonded to the lower surface of the dispersible absorbent layer 5, and the lower surface of the normal-temperature water-dispersible material layer 3 is bonded to the upper surface of the dispersible bottom layer 7. The periphery of the dispersible surface layer 4 is connected to the periphery of the high-impermeability dispersible leakproof layer 6, and the periphery of the dispersible absorbent layer 5 is covered and fixed by the dispersible surface layer 4 and the high-impermeability dispersible leakproof layer 6.

[0078] Example 5

[0079] The only difference between this embodiment and embodiment 4 is that in this embodiment, the particle size of the heat-generating microcapsules is changed to 90-100 meshes, and the mass ratio of the wall material to the core is changed to 8:2.

[0080] Example 6

[0081] The only difference between this embodiment and embodiment 3 is that in this embodiment, the film thickness of the high-temperature water-soluble film layer 1 is changed to 30 μm.

[0082] Example 7

[0083] The only difference between this embodiment and embodiment 1 is that in this embodiment, the film thickness of the high-temperature water-soluble film layer 1 is changed to 250 μm.

[0084] Example 8

[0085] The only difference between this embodiment and embodiment 5 is that in this embodiment, the mass ratio of the wall material to the core in the heat-generating microcapsules is changed to 9:1.

[0086] Comparative Example 1

[0087] The only difference between this comparative example and Example 1 is that in this comparative example, the high impermeability and dispersible leak-proof layer is replaced by a polyethylene film.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that in this comparative example, the high impermeability and dispersible leak-proof layer is replaced by a room temperature water-soluble polyvinyl alcohol film with a dissolution temperature of 20°C.

[0090] Test Case

[0091] The performance test of the anti-leakage layer of Examples 1 to 8 and Comparative Examples 1 to 2 was carried out, and the test method was as follows:

[0092] 1. Dispersibility:

[0093] Using the YS-381 flushability tester (shaking box), refer to GB2019 "Test method and evaluation method for flushability of disposable sanitary nonwoven materials". After the test sample is shaken in the shaking box for 60 minutes, the decomposition percentage of the test sample is recorded.

[0094] 2. Liquid separation time:

[0095] Lay a layer of absorbent paper on a horizontal surface, and then lay the test samples on the surface of the absorbent paper. Use a dropper to slowly drop 30 ml of simulated blood in the middle of the test sample. After dropping 30 mL, press a 1 kg weight on the surface of the test sample and let it stand. Observe the bottom of the absorbent paper every 5 minutes to see if there is any sign of moisture. The fastest time when it becomes wet is recorded as the liquid isolation time.

[0096] 3. Dissolution time:

[0097] The sample to be tested is placed in a YS-381 type flushability tester (shaking box), and the dissolution time of the high temperature water-soluble film layer of the test sample is recorded.

[0098] The test results are shown in Table 1.

[0099] Table 1

[0100]

[0101]

[0102] By analyzing the data in the above table, we can draw the following conclusions:

[0103] (1) According to the dispersion percentage, it can be seen that Examples 1 to 6 all have a high final dispersion rate, can achieve good water dispersibility, will not cause clogging of the sewer pipe, and meet the flushability requirements. The polyethylene film of Comparative Example 1 uses a thermoplastic polyethylene film that cannot be dissolved in water. Examples 3 and 5 cannot reach a 100% dispersion rate because the high-temperature water-soluble film selected in Example 3 has a too high dissolution temperature, and the microcapsule wall material selected in Example 5 is thicker and has a low internal heating core content, so the ability to dissolve the high-temperature film is low. Compared with Example 1, the decomposition percentage of Example 7 is significantly reduced because the high-temperature water-soluble film layer is too thick and not easy to be quickly dispersed. Compared with Example 5, the decomposition percentage of Example 8 is significantly reduced, it is difficult to achieve rapid dispersion, and it is easy to clog the toilet because the wall material content in its heating microcapsule is too high and the core content is too low, which will cause the high-temperature water-soluble film layer to be unable to quickly and continuously heat up until the film breaks and melts.

[0104] (2) According to the liquid isolation time, it can be seen that the liquid isolation time of Examples 1 to 5, Examples 7 to 8 and Comparative Example 1 is relatively long, which can meet the long-term liquid isolation requirements of disposable sanitary products. This is because the leakproof layers of Examples 1 to 5 and Examples 7 to 8 are all made of high-temperature water-soluble films with a melting temperature higher than 38°C. When they come into contact with room-temperature liquid during use, they will not soften and dissolve. Only when they encounter high-temperature water can they disperse and dissolve, so they can achieve long-term liquid isolation. The polyethylene film of Comparative Example 1 is insoluble in water and has good liquid isolation, but does not meet the dispersion requirements. It can be seen from Comparative Example 2 that when a room-temperature water-soluble film is used as the leakproof layer, the liquid isolation time is 5 minutes. When used for a long time, the leakproof layer will dissolve and break, and cannot meet the long-term liquid isolation requirements. Compared with Example 3, the liquid isolation time of Example 6 is shortened because the high-temperature water-soluble film layer is too thin and has a low tensile strength, and is prone to local leakage after being slightly wetted.

[0105] (3) According to the dissolution time, it can be seen that the high-temperature water-soluble films of Examples 1 to 6 can all be dissolved under the action of the heating layer to achieve the dispersion requirements. Comparative Example 1 does not dissolve at all because it uses a polyethylene film, and does not meet the requirement of being able to be thrown into the toilet. Comparative Example 2 is a room temperature water-soluble polyvinyl alcohol film, which dissolves the fastest in water. Example 3 uses a polyvinyl alcohol water-soluble film with a higher dissolution temperature (70°C), so the dissolution time is longer, reaching 40 minutes. Example 4 uses a thicker polyvinyl alcohol water-soluble film (200μm), so the dissolution time is longer, reaching 25 minutes, but all can achieve rapid dispersion and dissolution within 1 hour. However, the high-temperature water-soluble film layer in Example 7 is too thick, and the wall material content in the heating microcapsules of Example 8 is too high, and the core content is too low, making it difficult for the leak-proof layer to disperse and dissolve quickly within 1 hour.

[0106] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0107] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A highly impermeable and dispersible leakproof layer, characterized in that: The invention comprises a high-temperature water-soluble film layer (1) and a heating layer (2); the lower surface of the high-temperature water-soluble film layer (1) is bonded to the upper surface of the heating layer (2); the melting temperature of the high-temperature water-soluble film layer (1) is ≥38°C; the heating layer (2) comprises a heating material; the heating material is a heating microcapsule whose wall material is a room-temperature water-soluble film whose melting temperature is ≤25°C, and whose core is a material that releases heat when in contact with water, and the mass ratio of the wall material to the core is 2:8 to 8:

2.

2. The high-impermeability and dispersible leak-proof layer according to claim 1, characterized in that: It also comprises a room temperature water dispersible material layer (3); the upper surface of the room temperature water dispersible material layer (3) is bonded to the lower surface of the heating layer (2).

3. The high-impermeability and dispersible leak-proof layer according to claim 1, characterized in that: The core of the heat-generating microcapsule is one or more combinations of iron powder, aluminum powder, activated carbon, diatomaceous earth, sodium chloride, quicklime and sodium carbonate.

4. The high-impermeability and dispersible leak-proof layer according to claim 1, characterized in that: The particle size of the heat-generating microcapsules is 50-100 meshes.

5. The high-impermeability and dispersible leak-proof layer according to claim 1, characterized in that: The amount of the heating material added in the high impermeability and dispersible leakage-proof layer is 5-15 g / m 2 .

6. The high-impermeability and dispersible leak-proof layer according to claim 1, characterized in that: The thickness of the high-temperature water-soluble film layer (1) is 50-200 μm.

7. A method for preparing a high-impermeability and dispersible leak-proof layer as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: The heating material is made into a heating layer and fixed under the high-temperature water-soluble film to form a highly impermeable and flushable anti-leakage layer.

8. A flushable absorbent sanitary product, characterized in that: It comprises a highly impermeable and dispersible leak-proof layer (6) as claimed in any one of claims 1 to 6.

9. The flushable absorbent sanitary product according to claim 8, characterized in that A dispersible absorption layer (5) is provided above the high-impermeability dispersible leakage-proof layer (6); the upper surface of the high-temperature water-soluble film layer (1) is in contact with the lower surface of the dispersible absorption layer (5); and a dispersible surface layer (4) is provided above the dispersible absorption layer (5).

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