A sanitary napkin with fast absorption speed and its preparation method

Abstract

This application relates to the field of feminine hygiene products, and specifically discloses a sanitary napkin with fast absorption speed and its preparation method. The sanitary napkin includes a surface layer, a diversion layer, an absorbent core, and a waterproof bottom film arranged in sequence. The diversion layer includes an upper hydrophilic layer and an anti-backflow layer. The upper hydrophilic layer is adhered to the surface layer, and the anti-backflow layer is adhered to the absorbent core. The upper hydrophilic layer is made of modified sulfonated carboxymethyl chitin fiber, and the anti-backflow layer is made of viscose fiber; the sulfonated carboxymethyl chitin fiber is prepared from artificial fiber, sulfonated carboxymethyl chitin, and a pore-forming agent; its preparation method includes the following steps: preparation of the upper hydrophilic layer; preparation of the diversion layer; preparation of the sanitary napkin. This application has the advantages of strong diversion ability and rapid dryness of the surface of the sanitary napkin; it solves the technical problem that the absorption speed of the sanitary napkin is not fast enough.

Description

Technical Field

[0001] The present application relates to the technical field of feminine hygiene products. More specifically, it relates to a sanitary napkin with a fast absorption speed and a preparation method thereof. Background Art

[0002] A sanitary napkin is a hygienic product with a liquid absorption function used by women during menstruation. With the continuous development of the hygiene product field, there are already various sanitary napkin products with basic liquid absorption functions on the market. During menstruation, a slow absorption speed of menstrual fluid will cause the sensitive skin to be in a wet state for a long time, and thus it is prone to damage. The absorption speed of menstrual fluid is closely related to the structure of the surface layer material and the water guiding ability of the diversion layer.

[0003] Currently, common ways to improve the liquid absorption ability of sanitary napkins are to increase the liquid absorption capacity of the water absorption layer, make high molecular resin water absorption cores, etc. There is abundant research data on the water absorption layer of sanitary napkins in China, but the progress achieved by unilaterally increasing the water storage capacity of the water absorption layer is obviously limited. To improve the liquid absorption speed of sanitary napkin products, it is also crucial to increase the diversion rate of the diversion layer. However, there is relatively little research on the diversion layer of sanitary napkins in China. Therefore, studying the diversion rate of the diversion layer is of great significance for solving the problem of the slow absorption speed of sanitary napkins. Summary of the Invention

[0004] In order to solve the problem that the skin dryness of women's sensitive parts is insufficient and thus prone to damage due to the slow absorption speed of sanitary napkins, and to improve the absorption speed of sanitary napkins, the present application provides a sanitary napkin with a fast absorption speed and a preparation method thereof.

[0005] In the first aspect, the present application provides a sanitary napkin with a fast absorption speed, adopting the following technical solution:

[0006] A sanitary napkin with a fast absorption speed includes a surface layer, a diversion layer, a water absorption core, and a waterproof bottom film arranged in sequence. The diversion layer includes an upper hydrophilic layer and an anti-backflow layer. The upper hydrophilic layer is made of sulfonated carboxymethyl chitin fiber, and the anti-backflow layer is made of viscose fiber; the sulfonated carboxymethyl chitin fiber is prepared from artificial fiber, sulfonated carboxymethyl chitin, and a pore-forming agent.

[0007] By adopting the above scheme, the lower anti-backflow layer prepared from viscose fiber in the present application is slightly denser in texture than the upper hydrophilic layer. It can form a diversion layer with a structure that is fluffy in the upper part and slightly dense in the lower part with the upper hydrophilic layer. Therefore, the different hygroscopicities of the upper and lower layers of fibers achieve a differential capillary effect, enabling the liquid contacting the upper hydrophilic layer to quickly pass through the diversion layer, thus playing a role in rapid diversion and preventing liquid backflow.

[0008] In addition, pore-forming agents are added during the preparation of the upper hydrophilic layer to form pores, increasing the fluffiness of the upper hydrophilic layer and enhancing the difference in hygroscopicity between the upper hydrophilic layer and the anti-infiltration layer, thereby providing a driving force for the diversion function of the diversion layer and improving the rapid diversion function.

[0009] In addition, the introduction of sulfonyl groups and carboxymethyl groups in the sulfonated carboxymethyl chitin of the upper hydrophilic layer in the present application not only realizes the hydrophilic modification of chitin, but also utilizes the introduced sulfonyl groups to endow the modified carboxymethyl chitin with heparin-like anticoagulant effects, effectively preventing blood coagulation from blocking pores, ensuring the smoothness of the liquid infiltration process, being more conducive to rapid diversion, and improving the diversion rate of the diversion layer.

[0010] Optionally, the sulfonated carboxymethyl chitin fiber is prepared from the following raw materials in parts by weight:

[0011] 18-24 parts of sulfonated carboxymethyl chitin, 70-80 parts of artificial fiber, and 6-10 parts of pore-forming agent.

[0012] Optionally, the preparation method of sulfonated carboxymethyl chitin is as follows: Weigh 40-50 parts of carboxymethyl chitin, dissolve it in sodium hydroxide solution, mix and stir for 2-3 hours, add 100-150 parts of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, dropwise add a chloroform solution containing 125-175 parts of p-toluenesulfonyl chloride and react in an ice bath for 2-3h, then react at room temperature for 2-3h, finally pour the reaction solution into water, collect the precipitate, wash it with water until neutral, then wash it with ethanol, and dry it to obtain sulfonated carboxymethyl chitin.

[0013] By adopting the above technical solution, the ordered structure existing between the macromolecules of carboxymethyl chitin will make the chain regularity large and rigid. Add an alkali solution with a certain concentration, and through the alkali absorption and diffusion of carboxymethyl chitin, alkalized carboxymethyl chitin is generated. During the alkalization process, the swelling of carboxymethyl chitin obtains the effect of opening the diffusion channels in the crystalline region and activating the reaction performance, which is more conducive to the sulfonylation of the C6 and C3 hydroxyl groups on carboxymethyl chitin by p-toluenesulfonyl chloride.

[0014] Optionally, the preparation method of carboxymethyl chitin is as follows: Mix 10-15 parts of chitin, 100-150 parts of sodium hydroxide aqueous solution, and 0.04-0.05 parts of sodium dodecyl sulfate, stir in a water bath at 20-25°C for 20-25h under nitrogen protection and in the dark, perform suction filtration to remove the excess sodium hydroxide solution, add 125-150 parts of isopropanol to the residue and stir evenly, dissolve 75-80 parts of chloroacetic acid in 93-100 parts of isopropanol to obtain a chloroacetic acid isopropanol solution, dropwise add the chloroacetic acid isopropanol solution at 8-12°C and react for 6-8h, and after dropping, raise the temperature to 12-16°C and react for 20-24h.

[0015] Preferably, the pore-forming agent is ammonium bicarbonate.

[0016] By adopting the above technical solution, the pore-forming agent occupies a position in a solid state during the fiber forming process. An easily volatile pore-forming agent is selected, and a pore structure is gradually formed with the change of temperature, enhancing the fluffiness of the fiber layer. The fiber structure with pores forms a fluffy upper hydrophilic layer, which has a hygroscopicity difference from viscose fiber, thereby providing a driving force for the diversion layer. Selecting ammonium bicarbonate as the pore-forming agent, during the volatilization process, compared with other pore-forming agents, only the temperature needs to be changed to 50 °C, and the reaction conditions are milder.

[0017] Preferably, bamboo fiber is used as the surface layer material.

[0018] By adopting the above technical solution, the surface layer material is naturally skin-friendly, has good strength, is resistant to contact and is not easily damaged.

[0019] In the second aspect, the present application provides a method for preparing a sanitary napkin with a fast water absorption speed, adopting the following technical solution:

[0020] A method for preparing a sanitary napkin with a fast absorption speed, comprising the following steps:

[0021] S1. Preparation of the upper hydrophilic layer: Mix artificial fiber raw materials and sulfonated carboxymethyl chitin fiber portions and dissolve them in an organic solvent NMP, add a pore-forming agent, and use the wet spinning method to make a sulfonated carboxymethyl chitin fiber layer; after textile forming, volatilize at a constant temperature of 50-55 °C for 1-2 h to make the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers;

[0022] S2. Preparation of the diversion layer: Press the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers and the anti-backflow layer composed of viscose fibers in a weight ratio of 1:(0.8-1.2) by hot air penetration bonding to form a diversion layer;

[0023] S3. Preparation of the sanitary napkin: Thermally press and combine the surface layer, the diversion layer, the water absorption core, and the anti-seepage bottom film from bottom to top to form a sanitary napkin. In summary, the present application has the following beneficial effects:

[0024] 1. In the present application, ammonium bicarbonate is preferably used as the pore-forming agent. Since the occupied pores will be left in the fiber layer after volatilization, the upper hydrophilic layer becomes fluffy, and a significant hygroscopicity difference effect between the upper hydrophilic layer and the lower anti-backflow layer is obtained.

[0025] 2. Since the present application uses modified sulfonated carboxymethyl chitin fibers as the upper hydrophilic layer and viscose fibers to make the anti-backflow layer, the different hygroscopicities of the upper and lower layers of fibers achieve a differential capillary effect, thereby achieving the effects of rapid diversion and anti-liquid backflow.

[0026] 3. The method of the present application uses the diversion layer with the above structure to quickly conduct liquid from the surface layer inward, enabling the liquid to diffuse longitudinally and quickly leave the surface layer and the skin, solving the technical problem of slow absorption speed of sanitary napkins and achieving the effect of accelerating the absorption speed of sanitary napkins.

[0027] 4. In the present application, through the sulfonylation modification of carboxymethyl chitin, not only the hydrophilic modification of chitin is realized, but also the introduced sulfonyl group can endow the modified carboxymethyl chitin with heparin-like anticoagulant effect, effectively preventing blood coagulation from blocking pores, ensuring the smooth downward infiltration of liquid, being more conducive to rapid diversion, and improving the diversion rate of the diversion layer. Detailed implementation mode

[0028] The examples further illustrate the present application in detail. It should be particularly noted that: for those not specifying specific conditions in the following examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. Except for special instructions, the raw materials used in the following examples can all be obtained from ordinary commercial sources.

[0029] The present application provides a preparation method of a sanitary napkin with fast absorption speed, including the following steps:

[0030] Preparation of sulfonylated carboxymethyl chitin: Weigh 40 - 50 parts of carboxymethyl chitin, dissolve it in sodium hydroxide solution, mix and stir for 2 - 3 hours, add 100 - 150 parts of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, dropwise add a chloroform solution containing 125 - 175 parts of p-toluenesulfonyl chloride and react in an ice bath for 2 - 3 h, then react at room temperature for 2 - 3 h. Finally, pour the reaction solution into water, collect the precipitate, wash it with water until neutral, then wash it with ethanol, and dry it to obtain sulfonylated carboxymethyl chitin.

[0031] Preparation of the upper hydrophilic layer: Mix 70 - 80 parts of artificial fiber raw materials and 18 - 24 parts of sulfonylated carboxymethyl chitin fibers and dissolve them in 100 - 150 parts of organic solvent NMP. Add 6 - 10 parts of pore-forming agent, and use the wet spinning method to make a sulfonylated carboxymethyl chitin fiber layer. After textile forming, volatilize it at a constant temperature of 50 - 55 °C for 1 - 2 h to make the upper hydrophilic layer composed of sulfonylated carboxymethyl chitin fibers.

[0032] Preparation of the diversion layer: Press the upper hydrophilic layer composed of sulfonylated carboxymethyl chitin fibers and the anti-backflow layer composed of viscose fibers in a weight ratio of 1:(0.8 - 1.2) by hot air penetration bonding method to form a diversion layer. Preparation of sanitary napkin: Bond the surface layer, diversion layer, water-absorbing core, and anti-seepage bottom film from bottom to top by hot pressing to form a sanitary napkin. The following is a detailed description with specific examples.

[0033] The following Preparation Examples 1 - 3 are preparation examples of carboxymethyl chitin

[0034] Preparation Example 1

[0035] A preparation method of carboxymethyl chitin, comprising the following steps:

[0036] Mix 10 kg of 60-mesh chitin, 100 kg of 40% sodium hydroxide aqueous solution, and 0.04 kg of sodium dodecyl sulfate. Under nitrogen protection and in the dark, stir in a 20°C water bath for 20 h, filter by suction, remove the excess sodium hydroxide solution, add 125 kg of isopropanol to the residue and stir evenly to obtain a mixture. Dissolve 75 kg of chloroacetic acid in 93 kg of isopropanol to obtain a chloroacetic acid isopropanol solution. Keep the mixture at 8°C, and dropwise add the chloroacetic acid isopropanol solution to the mixture and react for 8 h. After dropping, raise the temperature to 12°C and react for 24 h.

[0037] Preparation Example 2

[0038] Mix 12 kg of 70-mesh chitin, 125 kg of 40% sodium hydroxide aqueous solution, and 0.045 kg of sodium dodecyl sulfate. Under nitrogen protection and in the dark, stir in a 22°C water bath for 23 h, filter by suction, remove the excess sodium hydroxide solution, add 135 kg of isopropanol to the residue and stir evenly to obtain a mixture. Dissolve 77 kg of chloroacetic acid in 96 kg of isopropanol to obtain a chloroacetic acid isopropanol solution. Keep the mixture at 10°C, and dropwise add the chloroacetic acid isopropanol solution to the mixture and react for 7 h. After dropping, raise the temperature to 14°C and react for 22 h.

[0039] Preparation Example 3

[0040] Mix 15 kg of 80-mesh chitin, 150 kg of 40% sodium hydroxide aqueous solution, and 0.05 kg of sodium dodecyl sulfate. Under nitrogen protection and in the dark, stir in a 25°C water bath for 25 h, filter by suction, remove the excess sodium hydroxide solution, add 150 kg of isopropanol to the residue and stir evenly to obtain a mixture. Dissolve 80 kg of chloroacetic acid in 100 kg of isopropanol to obtain a chloroacetic acid isopropanol solution. Keep the mixture at 12°C, and dropwise add the chloroacetic acid isopropanol solution to the mixture and react for 8 h. After dropping, raise the temperature to 16°C and react for 24 h.

[0041] Example

[0042] Example 1

[0043] A preparation method of a sanitary napkin with fast absorption speed, comprising the following steps:

[0044] S1. Preparation of the upper hydrophilic layer:

[0045] S1-1: Weigh 40 g of the carboxymethyl chitin prepared in Preparation Example 1 and dissolve it in 0.1 mol / L sodium hydroxide solution. The volume ratio of the sodium hydroxide solution to the mass of the carboxymethyl chitin is 50 ml:10 g. Mix and stir for 2 hours, add 100 g of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, and dropwise add a chloroform solution containing 125 g of p-toluenesulfonyl chloride for ice bath reaction for 2 h (dropwise add after dissolving 125 g of p-toluenesulfonyl chloride in 400 ml of chloroform solution), then react at room temperature for 2 h. Finally, pour the reaction solution into water, collect the precipitate, wash it with water until neutral, and then wash it with ethanol and dry it to obtain sulfonated carboxymethyl chitin.

[0046] S1-2: Take 18 g of the sulfonated carboxymethyl chitin prepared in S1-1 and 70 g of ES fiber raw material and dissolve them in 100 g of NMP. Add 6 g of pore-forming agent ammonium bicarbonate, stir, and then use the wet spinning method to make a sulfonated carboxymethyl chitin fiber layer. After spinning and forming, volatilize it at a constant temperature of 50 °C for 2 h to make the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers;

[0047] S2: Preparation of the diversion layer:

[0048] Press the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers and the anti-backflow layer composed of viscose fibers into a diversion layer by hot air penetration bonding with a weight ratio of 1:0.8 (g).

[0049] S3: Preparation of sanitary napkin: Bond the surface layer, diversion layer, water-absorbing core, and anti-seepage bottom film from bottom to top, and bond the upper hydrophilic layer with the surface layer and the anti-backflow layer with the water-absorbing core by hot pressing to form a sanitary napkin. The surface layer material is bamboo fiber, the water-absorbing core raw material is acrylic-acrylamide copolymer fiber, and the anti-seepage bottom film is a PE film.

[0050] Example 2

[0051] A method for preparing a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that

[0052] S1: Preparation of the upper hydrophilic layer:

[0053] S1-1: Weigh 45 g of the carboxymethyl chitin prepared in Preparation Example 2 and dissolve it in 0.1 mol / L sodium hydroxide solution. The volume ratio of the sodium hydroxide solution to the mass of the carboxymethyl chitin is 55 ml:10 g. Mix and stir for 2.5 hours, add 125 g of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, and dropwise add a chloroform solution containing 150 g of p-toluenesulfonyl chloride for ice bath reaction for 2.5 h (dropwise add after dissolving 150 g of p-toluenesulfonyl chloride in 400 ml of chloroform solution), react at room temperature for 2.5 h. Finally, pour the reaction solution into water, collect the precipitate, wash it with water until neutral, and then wash it with ethanol and dry it to obtain sulfonated carboxymethyl chitin.

[0054] S1-2. Take 21 g of sulfonated carboxymethyl chitin prepared in S1-1 and 75 g of ES fiber raw material, dissolve them in 125 g of organic solvent NMP. Add 8 g of pore-forming agent, stir, and then use the wet spinning method to make a sulfonated carboxymethyl chitin fiber layer. After spinning and forming, volatilize at a constant temperature of 52 °C for 1.5 h to make the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers.

[0055] S2. Preparation of the diversion layer: Press the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers and the anti-leakage layer composed of viscose fibers together by hot air penetration bonding at a weight ratio of 1:1 to form the diversion layer.

[0056] Example 3

[0057] A preparation method of a sanitary napkin with a fast absorption rate is carried out according to the method in Example 1, except that in S1-1, weigh 50 g of carboxymethyl chitin prepared in Preparation Example 3, dissolve it in 0.1 mol / L sodium hydroxide solution, and the volume ratio of the sodium hydroxide solution to the mass of carboxymethyl chitin is 60 ml:10 g. Mix and stir for 3 hours, add 150 g of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, dropwise add a chloroform solution containing 175 g of p-toluenesulfonyl chloride and react in an ice bath for 3 h (dropwise add after 175 g of p-toluenesulfonyl chloride is dissolved in 400 ml of chloroform solution), react at room temperature for 3 h, finally pour the reaction solution into water, collect the precipitate, wash it with water until neutral, then wash it with ethanol, and dry it to obtain sulfonated carboxymethyl chitin.

[0058] S1-2. Take 24 g of sulfonated carboxymethyl chitin prepared in S1-1 and 80 g of ES fiber raw material, dissolve them in 150 g of organic solvent NMP. Add 8 g of pore-forming agent, stir, and then use the wet spinning method to make a sulfonated carboxymethyl chitin fiber layer. After spinning and forming, volatilize at a constant temperature of 52 °C for 1.5 h to make the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers.

[0059] S2. Preparation of the diversion layer: Press the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fibers and the anti-leakage layer composed of viscose fibers together by hot air penetration bonding at a weight ratio of 1:1.2 to form the diversion layer.

[0060] Example 4

[0061] A preparation method of a sanitary napkin with a fast absorption rate is carried out according to the method in Example 1, except that in S1-2, the ES fiber raw material is equally replaced with polypropylene fiber raw material.

[0062] Comparative Example

[0063] Comparative Example 1

[0064] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that in step S3, the upper hydrophilic layer of the diversion layer is attached to the absorbent core, and the anti-backflow layer is attached to the surface layer, and they are thermally pressed together to form a sanitary napkin.

[0065] Comparative Example 2

[0066] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that the sulfonated carboxymethyl chitin fiber in the upper hydrophilic layer is replaced with carboxymethyl chitin fiber in equal amount, that is, the sulfonated carboxymethyl chitin in steps S1-2 is replaced with the carboxymethyl chitin obtained in Preparation Example 1 in equal amount.

[0067] Comparative Example 3

[0068] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that the sulfonated carboxymethyl chitin fiber in the upper hydrophilic layer is replaced with sulfonated chitin fiber in equal amount. That is, the raw material carboxymethyl chitin in step S1-1 is replaced with chitin in equal amount, and then sulfonated chitin ggg is obtained according to the method in step S1-1.

[0069] Comparative Example 4

[0070] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that the sulfonated carboxymethyl chitin fiber in the upper hydrophilic layer is replaced with a mixture of sulfonated chitin fiber and carboxymethyl chitin fiber with a weight ratio of 1:1 gg. That is, the sulfonated carboxymethyl chitin in step S1-2g is replaced with sulfonated chitin and carboxymethyl chitin with a mass ratio of 1:1 in equal amount. The carboxymethyl chitin is the carboxymethyl chitin prepared in Preparation Example 1, and the sulfonated chitin is obtained by replacing the raw material carboxymethyl chitin in step S1-1 with chitin in equal amount and according to the method in step S1-1.

[0071] Comparative Example 5

[0072] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that the ES fiber in the upper hydrophilic layer in step S1-2 is replaced with cotton fiber in equal amount.

[0073] Comparative Example 6

[0074] A preparation method of a sanitary napkin with fast absorption speed is carried out according to the method in Example 1, except that no pore-forming agent is added in step S1-2.

[0075] Comparative Example 7

[0076] A preparation method of a sanitary napkin with fast absorption speed, which is carried out according to the method in Example 1. The difference is that the raw material sulfonated carboxymethyl chitin in step S1-2 is replaced with chitin in equal amount, and finally the upper hydrophilic layer is made of chitin fiber.

[0077] Comparative Example 8

[0078] A preparation method of a sanitary napkin with fast absorption speed, which is carried out according to the method in Example 1. The difference is that the preparation process of the diversion layer in step S2 is changed to: the upper hydrophilic layer composed of ES fiber and the anti-backflow layer composed of viscose fiber are laminated into a diversion layer by hot air penetration bonding method according to the weight ratio of g being 1:0.8.

[0079] Performance detection test

[0080] 1. Liquid penetration time test

[0081] Test standard: FZT 60017--93 Test method for liquid penetration of thin nonwovens for sanitary use.

[0082] 2. Liquid holding rate test

[0083] Detection method / test method

[0084] 1. Liquid penetration time test: A certain amount of artificial urine is flowed onto the diversion layer specimen laid flat on a standard absorbent core liner according to the specified method. According to the FZT 60017-93 test method for liquid penetration of thin nonwovens for sanitary use, the time required for all the liquid to penetrate through the diversion layer specimen is measured by an electrical measurement method. Calculate the measured average penetration time.

[0085] 2. Liquid holding rate determination:

[0086] The liquid holding rate refers to the amount of liquid retained per unit mass of the material when a certain pressure is applied to the fully wetted material for a certain period of time, usually expressed as a percentage. The diversion layer needs to quickly contact a large amount of liquid, release the absorbed liquid under a certain pressure condition, and transport the liquid to the absorbent core, thus creating conditions for continuous diversion. Therefore, the smaller the liquid holding rate, the better the continuous diversion ability of the diversion layer.

[0087] The steps for determining the liquid holding rate are as follows: First, measure the dry weight M1 of the specimen. According to the test method of the liquid absorption rate, the diversion layer specimen is fully swollen with artificial urine for 1 h, then quickly placed on the surface of the standard absorbent paper, and at the same time, a standard pressure block with a length and width of 100 mm x 100 mm and a mass of 1.20 kg is pressed on the specimen. When the pressure is applied for 1 min, the standard pressure block is removed, and the mass M2 of the diversion layer specimen is weighed with a balance. Then the liquid holding rate Lr(%) is shown in the formula. Lr = (M2 - M1) / M1 x 100%

[0088] The liquid penetration time and liquid holding rate of the diversion layer in the examples and comparative examples were measured respectively according to the above method, and the measurement results are shown in Tables 1 and 2 below:

[0089] Table 1 Test Results of Examples

[0090] Example 1 Example 2 Example 3 Example 4 Liquid penetration time / s 1.48 1.31 1.46 1.37 Liquid holdup rate / % 19.12 18.44 19.06 19.94

[0091] Table 2 Test Results of Comparative Examples

[0092]

[0093] Combined with the test results of Examples 1, 2, and 3, it can be concluded that the diversion layers prepared according to the present application have all achieved the effect of rapid diversion and accelerated liquid absorption, and the effect of Example 2 is better. Combining Examples 1 and 4, it can be concluded that among the two fibers of ES fiber and polypropylene fiber selected in the present application, from the two aspects of liquid penetration time and liquid holding rate, they both have excellent diversion ability, and can quickly send the liquid to the water-absorbing core, thereby accelerating the absorption speed of the sanitary napkin.

[0094] Combined with the test results of Example 1 and Comparative Example 6, it can be seen that since the fiber layer without the addition of pore-forming agent does not form pores, the fluffiness of the upper hydrophilic layer is not enhanced, and it is difficult to form a structure with a loose upper layer and a dense lower layer. The differential capillary effect is not significant, and the effect is significantly different from that of the example. Thus, it can be seen that forming pores is the key to the water conduction ability of the upper hydrophilic diversion layer.

[0095] Combined with the test results of Example 1 and Comparative Example 1, it can be seen that when viscose fiber is used as the upper layer and sulfonated carboxymethyl chitin fiber is used as the lower layer, the liquid penetration speed is significantly slowed down, the water absorption rate is reduced, and the liquid holding rate increases significantly. It can be seen that the arrangement of the upper and lower layer structures is the main factor affecting the liquid holding rate, and its effect proves that the upper hydrophilic layer should be a loose structure of sulfonated carboxymethyl chitin fiber, and the lower layer is viscose fiber.

[0096] Combined with the test results of Example 1 and Comparative Examples 2, 3, and 4, it can be seen that the penetration time increases when using carboxymethyl chitin fiber or sulfonated chitin fiber, and the liquid holding rate decreases. Although carboxymethyl chitin fiber also has good hydrophilicity, it does not have the function of anticoagulation and cannot change the fluidity of blood to accelerate drainage. Therefore, the liquid penetration time increases and the liquid holding rate increases to some extent. For sulfonated chitin fiber, it also requires the strong hydrophilicity of the carboxymethyl group to obtain better hydrophilic ability. It can be seen that adding sulfonated carboxymethyl chitin in Example 1 has a better diversion effect than adding only carboxymethyl chitin or sulfonated chitin, or adding sulfonated chitin and carboxymethyl chitin at the same time. This may be related to the structure in which sulfonyl and carboxymethyl are simultaneously grafted on the chitin chain segment in the present application.

[0097] Combined with the test results of Example 1 and Comparative Example 7, it can be concluded that when chitin fiber is used as the fiber of the upper hydrophilic layer, the penetration time is greatly increased, the liquid holding rate is greatly reduced, the hydrophilicity is general, and the diversion ability is general, and the technical problem of slow absorption speed of sanitary napkins cannot be well solved.

[0098] Combined with the test results of Example 1 and Comparative Example 8, it can be concluded that when the upper hydrophilic layer fiber is composed of ES fiber, the penetration time is greatly increased, the liquid holding rate is increased, the performance of the upper hydrophilic layer is insufficient, and the diversion layer does not play a good role in accelerating the absorption speed of sanitary napkins.

[0099] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A sanitary napkin with fast absorption speed, comprising a surface layer, a diversion layer, an absorbent core and a waterproof bottom film arranged in sequence, characterized in that, The diversion layer includes an upper hydrophilic layer and an anti-backflow layer. The upper hydrophilic layer is adhered to the surface layer, and the anti-backflow layer is adhered to the water-absorbing core. The upper hydrophilic layer is made of sulfonated carboxymethyl chitin fiber, and the anti-backflow layer is made of viscose fiber; the sulfonated carboxymethyl chitin fiber is prepared from artificial fiber, sulfonated carboxymethyl chitin and a pore-forming agent.

2. The sanitary napkin with fast absorption speed according to claim 1, characterized in that, The sulfonated carboxymethyl chitin fiber is prepared from the following raw materials by weight: 18-24 parts of sulfonated carboxymethyl chitin, 70-80 parts of artificial fiber, and 6-10 parts of pore-forming agent.

3. The sanitary napkin with fast absorption speed according to claim 2, characterized in that: The preparation method of the sulfonated carboxymethyl chitin is as follows: by weight, weigh 40-50 parts of carboxymethyl chitin, dissolve it in sodium hydroxide solution, mix and stir for 2-3 hours, add 100-150 parts of ice cubes, stir the mixture to obtain a clear solution, cool it in an ice bath, dropwise add a chloroform solution containing 125-175 parts of p-toluenesulfonyl chloride and react in an ice bath for 2-3h, then react at room temperature for 2-3h, finally pour the reaction solution into water, collect the precipitate, wash it with water until neutral, then wash it with ethanol, and dry it to obtain sulfonated carboxymethyl chitin.

4. The sanitary napkin with fast absorption speed according to claim 3, characterized in that: The preparation method of the carboxymethyl chitin is as follows: by weight: mix 10-15 parts of chitin, 100-150 parts of sodium hydroxide aqueous solution, and 0.04-0.05 parts of sodium dodecyl sulfate, stir in a water bath at 20-25°C for 20-25h under nitrogen protection and in the dark, filter, remove the excess sodium hydroxide solution, add 125-150 parts of isopropanol to the residue and stir evenly, dissolve 75-80 parts of chloroacetic acid in 93-100 parts of isopropanol to obtain a chloroacetic acid isopropanol solution, dropwise add the chloroacetic acid isopropanol solution at 8-12°C and react for 6-8h, and after dropping, raise the temperature to 12-16°C and react for 20-24h.

5. The sanitary napkin with fast absorption speed according to claim 1, characterized in that: The artificial fiber is one of ES fiber and polypropylene fiber.

6. The sanitary napkin with fast absorption speed according to claim 1, characterized in that: The pore-forming agent is ammonium bicarbonate.

7. The sanitary napkin with fast absorption speed according to claim 1, characterized in that: The surface layer adopts a fiber web formed by directly laying bamboo fibers.

8. A method for preparing the sanitary napkin with fast absorption speed according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Preparation of the upper hydrophilic layer: Mix the artificial fiber raw material with sulfonated carboxymethyl chitin fiber and dissolve it in the organic solvent NMP, add a pore-forming agent, and use the wet spinning method to make a sulfonated carboxymethyl chitin fiber layer; after textile forming, volatilize at a constant temperature of 50-55°C for 1h-2h to make the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fiber; S2. Preparation of the diversion layer: Press the upper hydrophilic layer composed of sulfonated carboxymethyl chitin fiber and the anti-backflow layer composed of viscose fiber into a diversion layer by hot air penetration bonding method according to the weight ratio of 1: (0.8-1.2); S3. Preparation of the sanitary napkin: Bond the surface layer, the diversion layer, the water-absorbing core, and the anti-seepage bottom film from bottom to top by hot pressing to form a sanitary napkin.

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