Sanitary napkin product with foaming elastic absorber and preparation method of sanitary napkin product

Abstract

The invention discloses a sanitary napkin product with a foaming elastic absorber and a preparation method of the sanitary napkin product, and belongs to the technical field of hygienic products, the sanitary napkin product is sequentially composed of a skin-friendly surface layer, the elastic absorber and a waterproof breathable layer from top to bottom, and the elastic absorber is sequentially composed of a diffusion layer, a liquid guide and moisture insulation layer, an anti-reverse osmosis foaming layer and a foaming absorption layer from top to bottom; the preparation method comprises the following steps: mixing raw materials of the foaming absorption layer, and performing constant-temperature foaming to obtain the foaming absorption layer; raw materials of an anti-reverse-osmosis foaming layer are mixed and then coated between the foaming absorption layer and the liquid guide and moisture insulation layer, heating foaming is performed to form the anti-reverse-osmosis foaming layer, and a diffusion layer is bonded to the surface of the liquid guide and moisture insulation layer to obtain an elastic absorber; sequentially bonding the skin-friendly surface layer, the elastic absorber and the waterproof breathable layer to obtain a sanitary towel product; the sanitary napkin product provided by the invention has good absorptivity, reverse osmosis resistance and surface dryness.

Description

Technical Field

[0001] The present invention relates to the technical field of sanitary products, and in particular to a sanitary napkin product with a foamed elastic absorbent and a preparation method thereof. Background Art

[0002] Sanitary napkins are sanitary products used by women during menstruation. They are generally composed of a surface layer, an absorbent core and a bottom layer. The absorbent core of a sanitary napkin usually contains a certain amount of fluff pulp or fluff pulp fibers. Although this type of absorbent core absorbs liquid quickly, it has the defect of a short liquid diffusion distance. The absorbent core is prone to clumps and breaks after absorbing liquid, and is prone to leakage after absorbing liquid multiple times. In addition, the fluff pulp dust is large during the production process and is easy to fall onto the surface of the sanitary napkin, causing allergies. In addition, the absorbent core also contains polymer absorbent resins, which can absorb a large amount of water. However, in addition to water, menstrual blood also contains complex components such as metal ions and secretions, and polymer absorbent resins have a poor ability to absorb components other than water, which affects the absorption performance of the sanitary napkin.

[0003] The Chinese patent with publication number CN107837144A discloses a liquid-absorbent and breathable sanitary napkin, which is composed of a skin-friendly dry layer, a liquid-absorbent core layer, a breathable and water-repellent layer and a breathable cotton layer from top to bottom. The liquid-absorbent core layer is composed of a dust-free paper layer 1, a high-absorbent resin layer 1, a puffed cotton layer, a high-absorbent resin layer 2 and a dust-free paper layer 2 from top to bottom. The breathable and water-repellent layer is provided with water-repellent and breathable small holes, which can allow gas to flow and the water-repellent and breathable small holes can block liquid. Body circulation; the liquid-absorbent core layer of the sanitary napkin is composed of dust-free paper, absorbent resin, expanded cotton, absorbent resin, and dust-free paper in sequence. Among the materials used to absorb liquid, the absorbent core has a high content of absorbent resin, but the absorbent resin has a poor absorption capacity for components other than water in menstrual blood. When the sanitary napkin is squeezed by external force, these unabsorbed components are likely to form a stream of liquid that permeates back to the surface of the sanitary napkin, affecting the dryness and comfort of the surface of the sanitary napkin. Therefore, there is still room for improvement. Summary of the invention

[0004] In view of the technical defects existing in the background technology, the present invention proposes a sanitary napkin product with a foamed elastic absorbent and a preparation method thereof, which solves the above technical problems and meets the actual needs. The specific technical solution is as follows: A sanitary napkin product with a foam elastic absorbent, comprising a skin-friendly surface layer, an elastic absorbent, and a waterproof and breathable layer arranged in sequence from top to bottom, wherein the elastic absorbent is composed of a diffusion layer, a liquid-conducting and moisture-isolating layer, an anti-reverse osmosis foaming layer, and a foaming absorbent layer in sequence from top to bottom; The anti-reverse osmosis foaming layer comprises the following components by mass: 80-120 parts of waterborne polyurethane resin, 2-4 parts of water-absorbing filler, 0.5-2 parts of foaming agent, and 0.1-0.5 parts of foam stabilizer; The foaming absorption layer comprises the following components by mass: 60-90 parts of polyether polyol, 10-20 parts of polyester polyol, 35-65 parts of isocyanate, 2-8 parts of deionized water, 0.5-2 parts of water-absorbing filler, and 0.3-1.5 parts of cross-linking agent.

[0005] As a further technical solution of the present invention, the water-absorbing filler is selected from one or more of sodium polyacrylate water-absorbing resin, polyacrylamide water-absorbing resin, starch-based water-absorbing material, and cellulose-based water-absorbing material.

[0006] As a further technical solution of the present invention, the foaming agent is modified sodium bicarbonate, and the foaming temperature of the foaming agent is 100-120° C.; the foam stabilizer is selected from one of ethylene oxide-propylene oxide copolymer and bisphenol A-epichlorohydrin-polyoxyethylene glycol adduct.

[0007] As a further technical solution of the present invention, the polyether polyol is selected from one of polyoxypropylene glycol and polyoxypropylene ethylene oxide copolyether glycol or a mixture of two of them, and the molecular weight of the polyether polyol is 800-2000; the polyester polyol is obtained by polycondensation with adipic acid and glycol using ethylene glycol as an initiator; the isocyanate is selected from one of 4,4'-diphenylmethane diisocyanate and carbodiimide-modified 4,4'-diphenylmethane diisocyanate or a mixture of two of them; the crosslinking agent is selected from one or more of trimethylolpropane, glycerol and diethanolamine.

[0008] As a further technical solution of the present invention, the skin-friendly surface layer is selected from hot air non-woven fabric, spunlace non-woven fabric, and hot-rolled non-woven fabric; the waterproof and breathable layer is selected from a waterproof and breathable polyethylene film.

[0009] As a further technical solution of the present invention, the diffusion layer is made of a first needle-punched non-woven fabric, and the first needle-punched non-woven fabric is composed of one or a mixture of hollow bamboo fibers and hollow viscose fibers.

[0010] As a further technical solution of the present invention, the liquid-conducting and moisture-isolating layer is made of a second needle-punched non-woven fabric, which includes the following components by mass: 30%~50% modified fibers and 50%~70% super absorbent fibers; the modified fibers are selected from one or more of ES fibers, polypropylene fibers, polyester fibers, and polylactic acid fibers; the super absorbent fibers are selected from one or a mixture of hollow bamboo fibers and hollow viscose fibers.

[0011] A method for preparing a sanitary napkin product with a foamed elastic absorbent, comprising the following steps: S1, mixing and stirring polyether polyol, polyester polyol, water-absorbing filler and cross-linking agent, adding isocyanate and deionized water and continuing to stir to obtain foaming slurry, foaming the foaming slurry at a constant temperature, aging and cooling to obtain a foaming absorption layer; S2, mixing and stirring the waterborne polyurethane resin, the water-absorbing filler, the foaming agent, and the foam stabilizer to obtain a foaming oil; S3, after the foaming oil is evenly coated on the upper surface of the foaming absorption layer and the lower surface of the liquid-conducting and moisture-insulating layer, the liquid-conducting and moisture-insulating layer is covered on the upper surface of the foaming absorption layer, the foaming oil is heated to foam, and then matured and cooled to form an anti-reverse osmosis foaming layer between the foaming absorption layer and the liquid-conducting and moisture-insulating layer, and the diffusion layer is bonded to the upper surface of the liquid-conducting and moisture-insulating layer to obtain an elastic absorbent; S4, bonding the skin-friendly surface layer, the elastic absorbent body, and the waterproof and breathable layer in sequence to obtain a sanitary napkin product.

[0012] As a further technical solution of the present invention, in step S1, the temperature of the foaming slurry is constant temperature foaming at 30-40°C, and the temperature of the aging is 60-80°C.

[0013] As a further technical solution of the present invention, in step S3, the heating temperature of the foaming oil agent during foaming is 100-120°C, and the aging temperature is 60-80°C.

[0014] The beneficial effects of the present invention are: The elastic absorbent in the sanitary napkin product of the present invention serves as the main structure for absorbing liquid. In the elastic absorbent, a fine pore structure is formed between the foamed absorbent layer and the liquid-conducting and moisture-isolating layer through the anti-reverse osmosis foamed layer, and both the anti-reverse osmosis foamed layer and the foamed absorbent layer contain water-absorbing fillers, which improve the capillary effect and anti-reverse osmosis performance inside the elastic absorbent, so that the elastic absorbent can efficiently absorb liquid and lock the liquid inside. In addition, the foamed absorbent has good deformation resistance and is not easily squeezed by external force to cause the internal liquid to leak outward, further improving the anti-reverse osmosis performance inside the elastic absorbent, so that the surface of the sanitary napkin product can be kept dry, thereby improving the dryness and comfort of the sanitary napkin product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic diagram of the structure of a sanitary napkin product with a foamed elastic absorbent.

[0016] Figure 2 The present invention is a schematic diagram of the structure of an elastic absorbent body of a sanitary napkin product with a foamed elastic absorbent body.

[0017] Among them: a skin-friendly surface layer 1, an elastic absorbent body 2, a diffusion layer 21, a liquid-conducting and moisture-isolating layer 22, an anti-reverse osmosis foaming layer 23, a foaming absorption layer 24, and a waterproof and breathable layer 3. DETAILED DESCRIPTION

[0018] The implementation modes of the present invention are described below in conjunction with the accompanying drawings and relevant embodiments. The implementation modes of the present invention are not limited to the following embodiments, and the present invention relates to relevant necessary components in the technical field, which should be regarded as the known technology in the technical field and can be known and mastered by the technical personnel in the technical field.

[0019] like Figure 1 , 2 As shown, a sanitary napkin product with a foamed elastic absorbent body comprises a skin-friendly surface layer 1, an elastic absorbent body 2, and a waterproof and breathable layer 3 which are arranged in sequence from top to bottom; the elastic absorbent body 2 is composed of a diffusion layer 21, a liquid-conducting and moisture-isolating layer 22, an anti-reverse osmosis foaming layer 23, and a foaming absorption layer 24 in sequence from top to bottom; the anti-reverse osmosis foaming layer 23 comprises the following components by mass: 80-120 parts of an aqueous polyurethane resin, 2-4 parts of a water-absorbent filler, 0.5-2 parts of a foaming agent, and 0.1-0.5 parts of a foam stabilizer; the foaming absorption layer 24 comprises the following components by mass: 60-90 parts of a polyether polyol, 10-20 parts of a polyester polyol, 35-65 parts of an isocyanate, 2-8 parts of deionized water, 0.5-2 parts of a water-absorbent filler, and 0.3-1.5 parts of a cross-linking agent.

[0020] The sanitary napkin product of the present invention is mainly used to absorb menstrual blood discharged by women during menstruation, wherein the skin-friendly surface layer 1 is a non-woven fabric, which is mainly used as a structure in contact with the human body. The diffusion efficiency of menstrual blood on the surface of the sanitary napkin product can be improved by providing a guide groove or other structures on the surface of the skin-friendly surface layer 1, and the efficiency of menstrual blood penetrating into the interior of the sanitary napkin product can also be improved by providing a plurality of penetration holes or other structures on the surface of the skin-friendly surface layer 1; the elastic absorbent body 2 is the main structure of the sanitary napkin product for absorbing menstrual blood, and the elastic absorbent body 2 is composited with multiple layers of materials, and the diffusion layer 21 and the liquid-conducting and moisture-isolating layer 22 are both non-woven fabrics. The diffusion layer 21 promotes the diffusion of menstrual blood along the fiber extension direction through the internal fiber structure, thereby improving the diffusion of menstrual blood. The elastic absorbent 2 absorbs the menstrual blood uniformly within a certain range. The liquid-conducting and moisture-isolating layer 22 promotes the rapid downward penetration of the menstrual blood through the internal fiber structure. The anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24 are both foaming materials. The menstrual blood is absorbed and locked through the capillary effect produced by the rich internal pore structure. The anti-reverse osmosis foaming layer 23 and the liquid-conducting and moisture-isolating layer 22 jointly form an anti-reverse osmosis structure inside the elastic absorbent 2 to prevent the menstrual blood from reversely osmotic upward. The waterproof and breathable layer 3 serves as the bottom structure of the sanitary napkin product. It is bonded and fixed to the edge of the skin-friendly surface layer 1 to wrap the elastic absorbent 2 inside. The waterproof and breathable layer 3 can prevent the menstrual blood absorbed by the elastic absorbent 2 from penetrating and make the sanitary napkin product have a certain air permeability.

[0021] The sanitary napkin product of the present invention uses an elastic absorbent body 2 as the main absorption structure. Menstrual blood is evenly absorbed after diffusion and penetration in the elastic absorbent body 2, which can avoid the uneven distribution of menstrual blood in the elastic absorbent body 2 and the occurrence of clumping and the like. The elastic absorbent body 2 is provided with an anti-reverse osmosis foaming layer 23 and a liquid-conducting and moisture-isolating layer 22 to prevent menstrual blood from reversely osmotically penetrating the surface of the skin-friendly surface layer 1, thereby improving the dryness and comfort of the sanitary napkin product. In addition, the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24 added with absorbent fillers have good hydrophilicity, thereby firmly locking the menstrual blood in the internal pore structure. Moreover, the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24, which are foaming materials, have good softness, thereby further improving the comfort of the sanitary napkin product.

[0022] After adopting the above structure, the present invention is further described in combination with a method for preparing a sanitary napkin product. A method for preparing a sanitary napkin product with a foamed elastic absorbent comprises the following steps: S1, mixing and stirring polyether polyol, polyester polyol, water-absorbing filler and cross-linking agent, adding isocyanate and deionized water and continuing to stir to obtain foaming slurry, foaming the foaming slurry at a constant temperature of 30-40° C., and then aging and cooling the foaming slurry at 60-80° C. to obtain a foaming absorption layer 24; S2, mixing and stirring the waterborne polyurethane resin, the water-absorbing filler, the foaming agent, and the foam stabilizer to obtain a foaming oil; S3, after the foaming oil is evenly coated on the upper surface of the foaming absorption layer 24 and the lower surface of the liquid-conducting moisture-insulating layer 22, the liquid-conducting moisture-insulating layer 22 is covered on the upper surface of the foaming absorption layer 24, and the foaming oil is foamed by heating to 100-120°C, and then matured in an environment of 60-80°C and cooled to form an anti-reverse osmosis foaming layer 23 between the foaming absorption layer 24 and the liquid-conducting moisture-insulating layer 22, and the diffusion layer 21 is bonded to the upper surface of the liquid-conducting moisture-insulating layer 22 to obtain the elastic absorbent body 2; S4, bonding the skin-friendly surface layer 1, the elastic absorbent body 2, and the waterproof and breathable layer 3 in sequence to obtain a sanitary napkin product.

[0023] In step S1, the raw materials for making the foaming absorption layer 24 are mixed to form a foaming slurry. The polyether polyol, polyester polyol and isocyanate in the foaming slurry react to obtain polyurethane and serve as the main structure of the foaming absorption layer 24. Deionized water is used as a foaming agent for foaming to obtain a polyurethane sponge structure, which is the foaming absorption layer 24. In this reaction system, polyether polyol, polyester polyol and isocyanate are the main bodies of the reaction. The molecular structures of polyether polyol and polyester polyol both contain multiple hydroxyl structures. The hydroxyl group, as an active functional group, can react with isocyanate to obtain a carbamate bond, which is a key structure in the polyurethane molecular chain. In addition, the cross-linking agent can chemically react with the polyurethane molecules to form a cross-linked structure, and control the formation of bubbles during the foaming process and improve the stability of the process. The polyurethane molecules form a close network structure with each other during the reaction, and finally a polyurethane sponge structure with excellent physical properties is obtained after aging.

[0024] Furthermore, the raw materials of the foaming absorption layer 24 contain absorbent fillers, which can improve the hydrophilicity of the foaming absorption layer 24. After the foaming absorption layer 24 absorbs liquid, the liquid can better adhere to the inside of the foaming absorption layer 24, thereby ensuring the absorption performance of the elastic absorbent body 2. In addition, the raw materials of the foaming absorption layer 24 also contain polyester polyols, which can make the strength of the polyurethane sponge structure higher, thereby improving the support, tensile strength and deformation resistance of the foaming absorption layer 24. When the elastic absorbent body 2 is squeezed by external force, the foaming absorption layer 24 is not easy to deform and cause the liquid absorbed inside to leak outward, thereby improving the water locking, anti-reverse osmosis and other properties of the elastic absorbent body 2.

[0025] In step S2, in addition to the polyurethane resin, the aqueous polyurethane resin also contains necessary and commonly used ingredients such as isocyanate, oligomer polyol, cross-linking agent, solvent, thickener, film-forming aid and the like, which has coating properties similar to those of coatings. The foaming oil agent obtained by mixing the aqueous polyurethane resin with a water-absorbing filler, a foaming agent and a foam stabilizer also has similar coating properties, and contains a foaming agent and a foam stabilizer. The foaming oil agent can be cross-linked by heating to form polyurethane molecules, and at the same time, it is foamed by the foaming agent to form a polyurethane sponge structure, thereby forming an anti-reverse osmosis foaming layer 23 of a polyurethane sponge structure between the foaming absorption layer 24 and the liquid-conducting and moisture-isolating layer 22. At the same time, the foaming absorption layer 24 and the liquid-conducting and moisture-isolating layer 22 are bonded and fixed by the anti-reverse osmosis foaming layer 23, thereby improving the stability of the internal structure of the elastic absorbent 2.

[0026] In step S3, after the foaming oil agent is coated on the upper surface of the foaming absorption layer 24, part of the foaming oil agent will penetrate into the pore structure close to the surface of the foaming absorption layer 24, and another part of the foaming oil agent will adhere to the surface of the foaming absorption layer 24. After the foaming oil agent is coated on the lower surface of the liquid-conducting and moisture-insulating layer 22, part of the foaming oil agent will penetrate into the fiber gaps of the liquid-conducting and moisture-insulating layer 22, and another part of the foaming oil agent will adhere to the surface of the liquid-conducting and moisture-insulating layer 22. The foaming absorption layer 24 and the liquid-conducting and moisture-insulating layer 22 can be temporarily fixed by bonding with the foaming oil agent, and then the water-based polyurethane resin in the foaming oil agent is cross-linked by heating, and the foaming agent is decomposed to generate gas for foaming, thereby forming a polyurethane sponge structured anti-reverse osmosis foaming layer 23 between the foaming absorption layer 24 and the liquid-conducting and moisture-insulating layer 22. Finally, the diffusion layer 21 is bonded to the upper surface of the liquid-conducting and moisture-insulating layer 22 by an adhesive such as a hot melt adhesive to obtain the elastic absorbent body 2.

[0027] Furthermore, during the foaming process of the foaming oil agent, since part of the foaming oil agent penetrates into the foaming absorption layer 24 and the liquid conducting moisture-insulating layer 22, these foaming oil agents will also foam inside the foaming absorption layer 24 and the liquid conducting moisture-insulating layer 22 to form a polyurethane sponge structure with many pore structures, so that the anti-reverse osmosis foaming layer 23 is embedded in the foaming absorption layer 24 and the liquid conducting moisture-insulating layer 22, and the pore structure between the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24 is finer. At the same time, the fiber gaps on the side of the liquid conducting moisture-insulating layer 22 close to the anti-reverse osmosis foaming layer 23 are finer, thereby having a stronger capillary effect, so that the anti-reverse osmosis foaming layer 23 can hinder foaming. The liquid in the absorption layer 24 reversely osmose upward; in addition, if conventional processes are used to make the elastic absorbent body 2, adhesives such as hot melt adhesives are usually used to bond and fix the foamed absorption layer 24 to the liquid-conducting and moisture-isolating layer 22. The hot melt adhesive can easily penetrate into the pore structure of the foamed absorption layer 24 and block these pore structures, thereby reducing the absorption performance of the foamed absorption layer 24. The present invention uses an anti-reverse osmosis foam layer 23 as the bonding structure between the foamed absorption layer 24 and the liquid-conducting and moisture-isolating layer 22. The anti-reverse osmosis foam layer 23 will not block the pore structure of the foamed absorption layer 24, thereby ensuring the absorption performance of the foamed absorption layer 24 and improving the anti-reverse osmosis performance of the elastic absorbent body 2.

[0028] In step S4, the skin-friendly surface layer 1, the elastic absorbent body 2, and the waterproof and breathable layer 3 can be bonded in sequence by adhesives such as hot melt adhesives, and then the edges of the skin-friendly surface layer 1 and the waterproof and breathable layer 3 are bonded by hot pressing or other processes to form a sealed edge, and the elastic absorbent body 2 is wrapped inside by the skin-friendly surface layer 1 and the waterproof and breathable layer 3 to finally obtain the sanitary napkin product of the present invention.

[0029] To sum up, in the sanitary napkin product of the present invention, the elastic absorbent body 2 serves as the main structure for absorbing liquid. In the elastic absorbent body 2, the foaming absorption layer 24 and the liquid-conducting and moisture-isolating layer 22 form a fine pore structure through the anti-reverse osmosis foaming layer 23, and the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24 both contain absorbent fillers, which improve the capillary effect and anti-reverse osmosis performance inside the elastic absorbent body 2, so that the elastic absorbent body 2 can efficiently absorb liquid and lock the liquid inside. In addition, the foaming absorption layer 24 has good deformation resistance and is not easy to cause the internal liquid to leak out due to external force squeezing, further improving the anti-reverse osmosis performance inside the elastic absorbent body 2, so that the surface of the sanitary napkin product can be kept dry, thereby improving the dryness and comfort of the sanitary napkin product.

[0030] As one of the preferred embodiments of the present invention, the water-absorbing filler is selected from one or more of sodium polyacrylate water-absorbing resin, polyacrylamide water-absorbing resin, starch-based water-absorbing material, and cellulose-based water-absorbing material; the water-absorbing filler preferably obtains a granular water-absorbing filler with a particle size in the range of 0.1~0.3mm after grinding and screening the raw materials. The water-absorbing filler is used to improve the hydrophilicity and absorption performance of the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24, so that the liquid can be better adsorbed in the pores inside the polyurethane sponge structure and avoid reverse osmosis of these liquids.

[0031] As one of the preferred embodiments of the present invention, the foaming agent is modified sodium bicarbonate, and the foaming temperature of the foaming agent is 100-120°C; the foam stabilizer is selected from one of ethylene oxide-propylene oxide copolymer and bisphenol A-epichlorohydrin-polyoxyethylene glycol adduct; in step S3, the foaming oil agent needs to be heated to cause the components inside the water-based polyurethane resin to undergo cross-linking reaction to generate polyurethane molecules. In this process, the foaming agent can be heated to the foaming temperature to cause the foaming oil agent to foam, and finally a polyurethane sponge structure is obtained. At the same time, the foam stabilizer can improve the stability of the foam during the foaming process, thereby improving the stability of the polyurethane sponge structure.

[0032] As one of the preferred embodiments of the present invention, the polyether polyol is selected from one of polyoxypropylene glycol and polyoxypropylene ethylene oxide copolyether glycol or a mixture of two thereof, and the molecular weight of the polyether polyol is 800-2000; the polyester polyol is obtained by polycondensation with adipic acid and glycol using ethylene glycol as an initiator; the isocyanate is selected from one of 4,4'-diphenylmethane diisocyanate and carbodiimide-modified 4,4'-diphenylmethane diisocyanate or a mixture of two thereof; the crosslinking agent is selected from one or more of trimethylolpropane, glycerol and diethanolamine.

[0033] In the foaming slurry of the present invention, polyether polyol, polyester polyol and isocyanate are used as the main components for reacting to generate polyurethane molecules. These components undergo a cross-linking reaction under the action of a cross-linking agent and gradually generate polyurethane molecules. At the same time, they foam to form a polyurethane sponge structure, i.e., a foaming absorption layer 24, under the action of deionized water. The foaming absorption layer 24 contains polyether polyurethane molecules and polyester polyurethane molecules respectively. The polyether polyurethane molecules make the foaming absorption layer 24 have good flexibility and water resistance, and make the foaming absorption layer 24 present good softness and comfort and show better performance after absorbing water. The polyester polyurethane molecules can make the strength of the foaming absorption layer 24 higher, thereby improving the support, tensile strength and deformation resistance of the foaming absorption layer 24. When the elastic absorbent 2 is squeezed by external force, the foaming absorption layer 24 is not easy to deform and the liquid absorbed inside it leaks outward, thereby improving the water locking and anti-reverse osmosis properties of the elastic absorbent 2.

[0034] As one of the preferred embodiments of the present invention, the skin-friendly surface layer 1 is selected from one of hot air non-woven fabric, spunlace non-woven fabric, and hot-rolled non-woven fabric. These non-woven fabrics have good softness, which is beneficial to improving the comfort of sanitary napkin products; the waterproof and breathable layer 3 is made of waterproof and breathable polyethylene film. The waterproof and breathable polyethylene film can effectively prevent moisture penetration and avoid the liquid absorbed in the foaming absorption layer 24 from penetrating into the surface of the sanitary napkin product, while allowing air to penetrate, ensuring the breathability inside the sanitary napkin product, thereby improving its surface dryness.

[0035] As one of the preferred embodiments of the present invention, the diffusion layer 21 selects a first needle-punched non-woven fabric, and the first needle-punched non-woven fabric is composed of one or a mixture of hollow bamboo fiber and hollow viscose fiber; the diffusion layer 21 is a needle-punched non-woven fabric processed by needle punching fibers, and both the hollow bamboo fiber and the hollow viscose fiber have good air permeability and hygroscopicity, and have a certain capillary effect due to the hollow structure formed inside the fiber. After the diffusion layer 21 contacts the liquid, the liquid can be better diffused along the extension direction of the fiber, thereby increasing the diffusion range of the liquid.

[0036] As one of the preferred embodiments of the present invention, the liquid-conducting and moisture-isolating layer 22 is made of a second needle-punched non-woven fabric, which includes the following components by mass: 30% to 50% modified fibers and 50% to 70% super absorbent fibers; the modified fibers are selected from one or more of ES fibers, polypropylene fibers, polyester fibers, and polylactic acid fibers; the super absorbent fibers are selected from one or a mixture of hollow bamboo fibers and hollow viscose fibers.

[0037] In the liquid-conducting and moisture-isolating layer 22 of the present invention, the highly absorbent fiber has good hygroscopicity. The highly absorbent fiber absorbs liquid and promotes the liquid to penetrate downward. The modified fiber has a certain isolation effect on the liquid, which can prevent the liquid absorbed in the anti-reverse osmosis foaming layer 23 and the foaming absorption layer 24 from reversing upward, so that the liquid-conducting and moisture-isolating layer 22 can promote the liquid to penetrate downward and play an anti-reverse osmosis effect.

[0038] The present invention is further described below by way of examples and comparative examples.

[0039] Example 1

[0040] S1, 75 parts of polyether polyol, 15 parts of polyester polyol, 1.2 parts of sodium polyacrylate particles, and 0.9 parts of diethanolamine are mixed and stirred evenly, and then 55 parts of isocyanate and 5 parts of deionized water are added and stirred continuously to obtain a foaming slurry, and the foaming slurry is placed in a mold for constant temperature foaming, and then matured and cooled to obtain a foaming absorption layer; S2, 25 parts of waterborne polyurethane resin, 0.7 parts of sodium polyacrylate particles, 0.3 parts of modified sodium bicarbonate, and 0.07 parts of ethylene oxide-propylene oxide copolymer are mixed and stirred to obtain a foaming oil; S3, after the foaming oil is evenly coated on the upper surface of the foaming absorption layer and the lower surface of the liquid-conducting and moisture-insulating layer, the liquid-conducting and moisture-insulating layer is covered on the upper surface of the foaming absorption layer, the foaming oil is heated to foam, and then ripened and cooled to form an anti-reverse osmosis foaming layer between the foaming absorption layer and the liquid-conducting and moisture-insulating layer, and the diffusion layer is bonded to the upper surface of the liquid-conducting and moisture-insulating layer by hot melt adhesive to obtain an elastic absorbent body; S4, bonding the skin-friendly surface layer, the elastic absorbent body, and the waterproof and breathable layer in sequence by hot-melt adhesive to obtain a sanitary napkin product.

[0041] Example 2

[0042] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S1, the raw materials of the foaming absorption layer are composed of 60 parts of polyether polyol, 10 parts of polyester polyol, 0.5 parts of sodium polyacrylate particles, 0.3 parts of diethanolamine, 35 parts of isocyanate, and 2 parts of deionized water, and the operations of the remaining steps are the same.

[0043] Example 3

[0044] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S1, the raw materials of the foaming absorption layer are composed of 90 parts of polyether polyol, 20 parts of polyester polyol, 2 parts of sodium polyacrylate particles, 1.5 parts of diethanolamine, 65 parts of isocyanate, and 8 parts of deionized water, and the operations of the remaining steps are the same.

[0045] Example 4

[0046] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S2, the raw materials of the foaming oil agent are composed of 20 parts of aqueous polyurethane resin, 0.5 parts of sodium polyacrylate particles, 0.2 parts of modified sodium bicarbonate, and 0.05 parts of ethylene oxide-propylene oxide copolymer, and the operations of the remaining steps are the same.

[0047] Example 5

[0048] The difference between this embodiment and the above-mentioned embodiment 1 is that in step S2, the raw materials of the foaming oil agent are composed of 30 parts of aqueous polyurethane resin, 1 part of sodium polyacrylate particles, 0.5 parts of modified sodium bicarbonate, and 0.1 parts of ethylene oxide-propylene oxide copolymer, and the operations of the remaining steps are the same.

[0049] Comparative Example 1 S1, 75 parts of polyether polyol, 15 parts of polyester polyol, 1.2 parts of sodium polyacrylate particles, and 0.9 parts of diethanolamine are mixed and stirred evenly, and then 55 parts of isocyanate and 5 parts of deionized water are added and stirred continuously to obtain a foaming slurry, and the foaming slurry is placed in a mold for constant temperature foaming, and then matured and cooled to obtain a foaming absorption layer; S2, sequentially bonding the diffusion layer, the liquid-conducting and moisture-isolating layer, and the foaming absorption layer by hot-melt adhesive to obtain an elastic absorbent body; S3, bonding the skin-friendly surface layer, the elastic absorbent body, and the waterproof and breathable layer in sequence by hot-melt adhesive to obtain a sanitary napkin product.

[0050] Comparative Example 2 S1, 75 parts of polyether polyol, 15 parts of polyester polyol, 1.2 parts of sodium polyacrylate particles, and 0.9 parts of diethanolamine are mixed and stirred evenly, and then 55 parts of isocyanate and 5 parts of deionized water are added and stirred continuously to obtain a foaming slurry, and the foaming slurry is placed in a mold for constant temperature foaming, and then matured and cooled to obtain a foaming absorption layer; S2, 25 parts of waterborne polyurethane resin, 0.7 parts of sodium polyacrylate particles, 0.3 parts of modified sodium bicarbonate, and 0.07 parts of ethylene oxide-propylene oxide copolymer are mixed and stirred to obtain a foaming agent, the foaming agent is placed in a mold and heated to foam the foaming agent, and then aged and cooled to obtain an anti-reverse osmosis foaming layer; S2, sequentially bonding the diffusion layer, the liquid-conducting and moisture-isolating layer, the anti-reverse osmosis foaming layer, and the foaming absorption layer by hot melt adhesive to obtain an elastic absorbent body; S3, bonding the skin-friendly surface layer, the elastic absorbent body, and the waterproof and breathable layer in sequence by hot-melt adhesive to obtain a sanitary napkin product.

[0051] The sanitary napkin products of all the above embodiments and comparative examples were tested for absorption rate, absorption speed, rewet volume and air permeability. The test results are shown in Table 1 below:

[0052] Table 1 It can be seen from the data in Table 1 that the foaming absorption layer has a significant effect on the absorption rate, absorption speed and air permeability of the sanitary napkin product, while the anti-reverse osmosis foaming layer has a significant effect on the back osmosis amount and air permeability of the sanitary napkin product. The ratio of the raw materials in the foaming absorption layer and the anti-reverse osmosis foaming layer can be adjusted according to demand to adjust the performance of the sanitary napkin product and make the sanitary napkin product more widely applicable. In the sanitary napkin product of Comparative Example 1, the foaming absorption layer and the liquid-conducting and moisture-isolating layer are bonded by hot melt adhesive, resulting in many pore structures on the surface of the foaming absorption layer being blocked, and only the liquid-conducting and moisture-isolating layer has the anti-reverse osmosis function, so the absorption performance, anti-reverse osmosis performance and air permeability of the sanitary napkin product are significantly reduced. In the sanitary napkin product of Comparative Example 2, the foaming absorption layer and the liquid-conducting and moisture-isolating layer are bonded by hot melt adhesive, resulting in many pore structures on the surface of the foaming absorption layer being blocked, and only the liquid-conducting and moisture-isolating layer has the anti-reverse osmosis function, so the absorption performance, anti-reverse osmosis performance and air permeability of the sanitary napkin product are significantly reduced. The foam absorption layer, the anti-reverse osmosis foaming layer, and the liquid conducting and moisture-insulating layer are bonded in sequence by hot melt adhesive, resulting in that many pore structures on the surfaces of the foam absorption layer and the anti-reverse osmosis foaming layer are blocked. Therefore, the absorption performance and air permeability of the sanitary napkin product are significantly reduced. At the same time, the anti-reverse osmosis foaming layer is only fixed by a simple bonding method, and the pore structure between the anti-reverse osmosis foaming layer and the foam absorption layer and the liquid conducting and moisture-insulating layer cannot be made finer, resulting in that the anti-reverse osmosis foaming layer cannot play an anti-reverse osmosis effect in the sanitary napkin product. Therefore, the anti-reverse osmosis performance of the sanitary napkin product is also significantly reduced. It can be seen that the sanitary napkin products obtained in Examples 1 to 5 based on the technical solution of the present invention have relatively excellent comprehensive performance, and have better absorption performance, anti-reverse osmosis performance, and air permeability.

[0053] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A sanitary napkin product with a foamed elastic absorbent, comprising a skin-friendly surface layer, an elastic absorbent, and a waterproof and breathable layer arranged in sequence from top to bottom, characterized in that: The elastic absorbent body is composed of a diffusion layer, a liquid-conducting and moisture-isolating layer, an anti-reverse osmosis foaming layer, and a foaming absorption layer from top to bottom; The anti-reverse osmosis foaming layer comprises the following components by mass: 20-30 parts of aqueous polyurethane resin, 0.5-1 parts of water-absorbing filler, 0.2-0.5 parts of foaming agent, and 0.05-0.1 parts of foam stabilizer; The foaming absorption layer comprises the following components by mass: 60-90 parts of polyether polyol, 10-20 parts of polyester polyol, 35-65 parts of isocyanate, 2-8 parts of deionized water, 0.5-2 parts of water-absorbing filler, and 0.3-1.5 parts of cross-linking agent.

2. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The water-absorbing filler is selected from one or more of sodium polyacrylate water-absorbing resin, polyacrylamide water-absorbing resin, starch-based water-absorbing material, and cellulose-based water-absorbing material.

3. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The foaming agent is modified sodium bicarbonate, and the foaming temperature of the foaming agent is 100-120° C.; the foam stabilizer is selected from one of ethylene oxide-propylene oxide copolymer and bisphenol A-epichlorohydrin-polyoxyethylene glycol adduct.

4. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The polyether polyol is selected from one of polyoxypropylene glycol and polyoxypropylene ethylene oxide copolyether glycol or a mixture of the two, and the molecular weight of the polyether polyol is 800-2000; the polyester polyol is obtained by polycondensation with adipic acid and glycol using ethylene glycol as an initiator; the isocyanate is selected from one of 4,4'-diphenylmethane diisocyanate and carbodiimide-modified 4,4'-diphenylmethane diisocyanate or a mixture of the two; the crosslinking agent is selected from one or more of trimethylolpropane, glycerol and diethanolamine.

5. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The skin-friendly surface layer is selected from one of hot air non-woven fabric, spunlace non-woven fabric, and hot-rolled non-woven fabric; the waterproof and breathable layer is selected from a waterproof and breathable polyethylene film.

6. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The diffusion layer is made of a first needle-punched nonwoven fabric, which is composed of hollow bamboo fibers, hollow viscose fibers, or a mixture of the two.

7. The sanitary napkin product with a foamed elastic absorbent according to claim 1, characterized in that: The liquid-conducting and moisture-isolating layer is made of a second needle-punched non-woven fabric, which includes the following components by mass: 30% to 50% modified fibers and 50% to 70% highly absorbent fibers; the modified fibers are selected from one or more of ES fibers, polypropylene fibers, polyester fibers, and polylactic acid fibers; the highly absorbent fibers are selected from one or a mixture of hollow bamboo fibers and hollow viscose fibers.

8. A method for preparing a sanitary napkin product according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, mixing and stirring polyether polyol, polyester polyol, water-absorbing filler and cross-linking agent, adding isocyanate and deionized water and continuing to stir to obtain foaming slurry, foaming the foaming slurry at a constant temperature, aging and cooling to obtain a foaming absorption layer; S2, mixing and stirring the waterborne polyurethane resin, the water-absorbing filler, the foaming agent, and the foam stabilizer to obtain a foaming oil; S3, after the foaming oil is evenly coated on the upper surface of the foaming absorption layer and the lower surface of the liquid-conducting and moisture-insulating layer, the liquid-conducting and moisture-insulating layer is covered on the upper surface of the foaming absorption layer, the foaming oil is heated to foam, and then matured and cooled to form an anti-reverse osmosis foaming layer between the foaming absorption layer and the liquid-conducting and moisture-insulating layer, and the diffusion layer is bonded to the upper surface of the liquid-conducting and moisture-insulating layer to obtain an elastic absorbent; S4, bonding the skin-friendly surface layer, the elastic absorbent body, and the waterproof and breathable layer in sequence to obtain a sanitary napkin product.

9. The method for preparing a sanitary napkin product according to claim 8, characterized in that: In step S1, the temperature of the foaming slurry is constant temperature foaming at 30-40°C, and the temperature of the aging is 60-80°C.

10. The method for preparing a sanitary napkin product according to claim 8, characterized in that: In step S3, the heating temperature of the foaming oil agent during foaming is 100-120°C, and the aging temperature is 60-80°C.

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