Breathable backsheet for a paper diaper, and method for manufacturing and use thereof

Abstract

The application relates to a breathable bottom film for a paper diaper and a preparation method and application thereof, and comprises the following raw materials in parts by mass: 40-60 parts of polylactic acid, 15-30 parts of modified biological polysaccharide, 10-20 parts of effervescent agent and 10-20 parts of modified composite fiber; wherein the modified biological polysaccharide comprises the following raw materials in parts by mass: 30-50 parts of biological polysaccharide, 10-15 parts of hydrophobic agent and 1-3 parts of emulsifier, the biological polysaccharide is chitosan, hemicellulose and soap husk gum, and the hydrophobic agent is lac wax and / trifluoropropyl methyl silicone oil. The breathable bottom film has good water resistance, barrier property, air permeability, antibacterial property and certain mechanical strength, the comfort, safety and use performance of the paper diaper are increased, and the demand of the adult paper diaper bottom film on multifunctionality and reliability can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sanitary products, in particular to a breathable backsheet for paper diapers and a preparation method and application thereof. BACKGROUND

[0002] The latest structure of adult paper diapers mainly includes a top layer, an instant absorption and flow guide layer, an absorption core layer, a backsheet and other functional components. The backsheet of the adult paper diaper is the main factor affecting its breathability, which directly determines the breathability of the entire paper diaper and further affects the comfort of the adult wearer.

[0003] According to daily use, the breathable adult paper diapers currently sold on the market may cause the urine to penetrate through the backsheet and soil the clothes after the absorption core layer fully absorbs the urine. Therefore, a high-quality adult paper diaper backsheet not only needs to have good breathability, but also needs to have excellent waterproof and permeability. SUMMARY

[0004] The present application aims to overcome the deficiencies of the prior art and provide a breathable backsheet for paper diapers and a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] In a first aspect, the present application provides a breathable backsheet for paper diapers, comprising the following raw materials by mass fraction: 40-60 parts of polylactic acid, 15-30 parts of modified biological polysaccharide, 10-20 parts of effervescent agent and 10-20 parts of modified composite fiber; wherein the modified biological polysaccharide comprises the following raw materials by mass fraction: 30-50 parts of biological polysaccharide, 10-15 parts of hydrophobic agent and 1-3 parts of emulsifier, the biological polysaccharide being chitosan, hemicellulose and soap husk gum; the effervescent agent comprises the following raw materials by mass fraction: 10-15 parts of acid source, 10-15 parts of alkali source, 40-60 parts of modified composite fiber and 0.05-0.1 parts of surfactant.

[0007] The preparation method of the modified composite fiber comprises the following steps:

[0008] The composite fiber is subjected to beating treatment, the slurry of the composite fiber is mixed with a silver sulfate solution, and the modified composite fiber is obtained after drying; wherein the composite fiber is kapok fiber and soybean fiber.

[0009] The preparation method of the breathable backsheet for paper diapers comprises the following steps:

[0010] The polylactic acid, modified biological polysaccharide and modified composite fiber are mixed, extruded and molded, then stretched, cooled to obtain a bottom film, glue is sprayed on the surface of the bottom film, then effervescent agent is covered on the glue-sprayed surface of the bottom film, and after drying, the breathable bottom film for the paper diaper is obtained.

[0011] The main components of the breathable bottom film of the present application are polylactic acid, modified biological polysaccharide, effervescent agent and modified composite fiber, through the synergistic effect of raw material selection and process design, the multiple function balance of water resistance, barrier property, breathability, antibacterial property and mechanical strength is realized. The realization mechanism of each function is analyzed in detail from the material angle as follows:

[0012] Specifically, polylactic acid is used as the main material, which has certain mechanical strength, and has certain hydrophobicity because the main chain contains ester bond, so the polylactic acid can provide the bottom film with basic tensile strength, puncture resistance and water resistance.

[0013] The chitosan in the modified biological polysaccharide provides hydrophilic groups and antibacterial activity, and the hemicellulose constructs a continuous hydrophilic channel, and the soap husk gum optimizes the pore distribution. The chitosan before modification has hydrophilicity, but after hydrophobic modification, an alternating hydrophilic / hydrophobic structure is formed, which not only allows water vapor molecules to diffuse through hydrogen bond adsorption-desorption, but also blocks liquid water. After the chitosan in the modified biological polysaccharide is compounded with the hydrophobic agent, the amino and hydroxyl groups on the surface of the chitosan may be replaced by hydrophobic groups to form a micro-nano hydrophobic structure similar to the lotus leaf effect, and the hemicellulose and soap husk gum form a uniform dispersed hydrophobic network through the emulsifier to fill the gap between the polylactic acid molecular chains and block the capillary water absorption channel, thereby reducing the hydrophilicity of the biological polysaccharide and further enhancing the water resistance of the bottom film. The modified biological polysaccharide forms a dynamic breathable network through chemical modification and physical blending, which not only allows water vapor to diffuse through the hydrogen bond adsorption-desorption mechanism, but also blocks liquid water through micropores and interfacial hydrophobic areas, achieving a balance between breathability and water resistance.

[0014] The modified composite fiber is obtained by compounding the pulp of the composite fiber with a silver ion solution, and the silver ion provides antibacterial property for the composite fiber, and the hollow structure of the kapok fiber and the natural pores of the soybean fiber provide diffusion paths for water vapor, and the stretching process further expands the gap between the fibers, which makes the bottom film have good breathability. At the same time, the composite fiber as a reinforcing material can further improve the tensile strength of the bottom film.

[0015] The effervescent agent uses modified composite fiber as a carrier, and the acid source and the alkali source react to generate CO2 gas after the effervescent agent meets water, and the gas expands in the film to form micron-level connected pores, which promotes the outflow of water vapor, and realizes the effects of breathability and cooling.

[0016] The transparent bottom film of the present application realizes the synergy of air permeability, antibiosis and enhancement through a single-layer structure, avoids the process complexity and delamination risk caused by traditional multi-layer compounding. The effervescent agent dynamically generates air permeable holes after encountering water, realizing "on-demand air permeability", balancing the barrier property in dry state and the air permeability demand in wet state.

[0017] Preferably, in the preparation method of the modified composite fiber, the adding amount of the silver sulfate solution is 5-6 times of the total mass of the composite fiber, and the mass concentration of the silver sulfate solution is 40-60%; the soaking time is 1-3h.

[0018] Preferably, the mass ratio of the kapok fiber and the soybean fiber is 1: (3-5).

[0019] Preferably, the mass ratio of the chitosan, hemicellulose and soap husk gum is (2-4): 1: (0.5-1).

[0020] Preferably, the hydrophobic agent is a lacquer wax and a trifluoropropyl methyl silicone oil with a mass ratio of 1: (0.5-2); and the emulsifier is glycerol monostearate. The hydrophobic layer formed by the lacquer wax on the surface of the biological polysaccharide blocks liquid water, but the hydrophobic modification only acts on the surface groups of the biological polysaccharide without damaging its internal natural porous structure. The flexibility of the trifluoropropyl methyl silicone oil helps to maintain the softness of the bottom film and avoid the decrease of air permeability caused by excessive densification.

[0021] Preferably, in the preparation method of the air-permeable bottom film for paper diapers, the temperature of the extrusion molding is 150-180℃.

[0022] Preferably, in the preparation raw material of the effervescent agent, the acid source is citric acid, the alkali source is sodium bicarbonate, and the surfactant is sodium dodecyl sulfate.

[0023] Specifically, the preparation method of the effervescent agent comprises the following steps:

[0024] (1) mixing the modified composite fiber, water, sodium bicarbonate and sodium dodecyl sulfate, granulating, drying, sieving to obtain a powder with a particle size of 300-500;

[0025] (2) preparing citric acid into a powder with a particle size of 300-500;

[0026] (3) mixing the powders obtained in steps (1) and (2) to obtain the effervescent agent.

[0027] Preferably, in step (1) of the preparation method of the effervescent agent, the adding amount of water is 2-3 times of the modified composite fiber; and the drying temperature is 60-80℃.

[0028] In a second aspect, the present application provides the use of the air-permeable bottom film for paper diapers in the preparation of adult paper diapers.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] The modified composite fiber in the breathable bottom film of the present application simultaneously assumes the triple functions of reinforcement, effervescent carrier and antibiosis, avoiding multi-layer compounding. After the modified composite fiber, polylactic acid and modified biological polysaccharide are extruded into a film, sizing is performed on the surface of the bottom film, and then the effervescent agent is uniformly covered, so that the effervescent agent (acid source + alkali source) remains stable in a dry state and does not release gas before encountering water, avoiding the risk of leakage caused by the formation of pores in the film structure in advance. The breathable bottom film of the present application realizes the synergy of breathability, antibiosis and reinforcement through a single-layer structure, avoiding the process complexity and delamination risk caused by traditional multi-layer compounding. The effervescent agent dynamically generates breathable pores after encountering water, realizing "on-demand breathability", balancing the barrier property in a dry state and the breathability demand in a wet state. The breathable bottom film of the present application has good water resistance, barrier property, breathability, antibiosis and certain mechanical strength, increasing the comfort, safety and use performance of the paper diaper, and can meet the demand for multifunctionality and reliability of the bottom film of adult paper diapers. DETAILED DESCRIPTION

[0031] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0032] The raw materials used in the following examples and comparative examples are sourced from:

[0033] Chitosan: the manufacturer is Qingdao Yunzhu Biological Technology Co., Ltd., and the model is chitosan for textile use;

[0034] Hemicellulose: the manufacturer is Wuhan Lanna Bai Pharmaceutical Chemical Co., Ltd., and the model is DW3432;

[0035] Soap gellan gum: the manufacturer is Nanjing Songguan Biological Technology Co., Ltd.;

[0036] Shellac wax: the manufacturer is Keim-Additec, Germany, and the model is E-360;

[0037] Trifluoropropyl methyl silicone oil: the manufacturer is Shenzhen Ruitionwei Technology Co., Ltd., and the model is JP-401;

[0038] Polylactic acid: the manufacturer is Zhejiang Haizheng Biological Material Co., Ltd., and the model is REVODE110 / 190

[0039] Cotton fibers: the manufacturer is Dongguan Weixin Import and Export Co., Ltd., and the model is good Kapok (Kapok 100%);

[0040] Soybean fibers: the manufacturer is Guangzhou Jingsheng Technology Co., Ltd., and the model is A-09.

[0041] Other materials, reagents, etc. used in the examples and comparative examples were commercially available unless otherwise specified.

[0042] Example 1

[0043] A breathable bottom film for a paper diaper comprises the following raw materials in parts by mass: 52 parts of polylactic acid, 17 parts of modified biological polysaccharide, 13 parts of effervescent agent, and 15 parts of modified composite fiber; wherein the modified biological polysaccharide comprises the following raw materials in parts by mass: 32 parts of biological polysaccharide, 14 parts of hydrophobic agent, and 2 parts of emulsifier, the biological polysaccharide is chitosan, hemicellulose, and soap husk gum in a mass ratio of 3:1:0.8, the hydrophobic agent is lacquer wax and trifluoropropyl methyl silicone oil in a mass ratio of 1:1, and the emulsifier is glycerol monostearate;

[0044] The effervescent agent comprises the following raw materials in parts by mass: 12 parts of acid source, 12 parts of alkali source, 52 parts of modified composite fiber, and 0.06 parts of surfactant, the acid source is citric acid, the alkali source is sodium bicarbonate, and the surfactant is sodium dodecyl sulfate;

[0045] The preparation method of the modified composite fiber comprises the following steps:

[0046] The composite fiber is subjected to beating treatment, the slurry of the composite fiber is mixed with a silver sulfate solution, and the modified composite fiber is obtained after drying; wherein the composite fiber is kapok fiber and soybean fiber in a mass ratio of 1:4;

[0047] The preparation method of the effervescent agent comprises the following steps:

[0048] (1) The modified composite fiber, water, sodium bicarbonate, and sodium dodecyl sulfate are mixed and granulated, dried at 75°C, sieved, and a powder with a particle size of 400 μm is obtained; wherein the amount of water added is 3 times that of the modified composite fiber;

[0049] (2) The citric acid is made into a powder with a particle size of 400 μm;

[0050] (3) The powders obtained in steps (1) and (2) are mixed to obtain the effervescent agent.

[0051] The preparation method of the breathable bottom film for a paper diaper comprises the following steps:

[0052] The polylactic acid, modified biological polysaccharide, and modified composite fiber are mixed, extruded at 160°C, subjected to stretching treatment, cooled, and a bottom film is obtained, glue is sprayed on the surface of the bottom film, and then the effervescent agent is covered on the glue-sprayed surface of the bottom film, and the breathable bottom film for a paper diaper is obtained after drying.

[0053] Example 2

[0054] The breathable bottom film for a paper diaper comprises the following raw materials in parts by mass: 40 parts of polylactic acid, 15 parts of modified biological polysaccharide, 10 parts of effervescent agent and 10 parts of modified composite fiber; wherein the modified biological polysaccharide comprises the following raw materials in parts by mass: 30 parts of biological polysaccharide, 10 parts of hydrophobic agent and 1 part of emulsifier, the biological polysaccharide is chitosan, hemicellulose and soap husk gum with a mass ratio of 2:1:0.5, the hydrophobic agent is lacquer wax and trifluoropropyl methyl silicone oil with a mass ratio of 1:0.5, and the emulsifier is glycerol monostearate;

[0055] The effervescent agent comprises the following raw materials in parts by mass: 10 parts of acid source, 10 parts of alkali source, 40 parts of modified composite fiber and 0.05 parts of surfactant, the acid source is citric acid, the alkali source is sodium bicarbonate, and the surfactant is sodium dodecyl sulfate;

[0056] The preparation method of the effervescent agent comprises the following steps:

[0057] (1) mixing the modified composite fiber, water, sodium bicarbonate and sodium dodecyl sulfate, granulating, drying at 60℃, sieving and obtaining a powder with a particle size of 300μm; wherein the amount of water added is 2 times that of the modified composite fiber;

[0058] (2) preparing citric acid into a powder with a particle size of 300μm;

[0059] (3) mixing the powders obtained in steps (1) and (2) to obtain the effervescent agent.

[0060] The preparation method of the modified composite fiber comprises the following steps:

[0061] pulping the composite fiber, mixing the pulp of the composite fiber with a silver sulfate solution, taking out and drying to obtain the modified composite fiber; wherein the composite fiber is kapok fiber and soybean fiber with a mass ratio of 1:3;

[0062] The preparation method of the breathable bottom film for a paper diaper comprises the following steps:

[0063] mixing polylactic acid, modified biological polysaccharide and modified composite fiber, extruding and molding at 150℃, then performing stretching treatment, cooling, obtaining a bottom film, spraying glue on the surface of the bottom film, then covering the effervescent agent on the glue-sprayed surface of the bottom film, and drying to obtain the breathable bottom film for a paper diaper.

[0064] Example 3

[0065] The breathable bottom film for a paper diaper comprises the following raw materials in parts by mass: 60 parts of polylactic acid, 30 parts of modified biological polysaccharide, 20 parts of effervescent agent, and 20 parts of modified composite fiber; wherein the modified biological polysaccharide comprises the following raw materials in parts by mass: 50 parts of biological polysaccharide, 15 parts of hydrophobic agent, and 3 parts of emulsifier, the biological polysaccharide is chitosan, hemicellulose, and soap husk gum in a mass ratio of 4:1:1, the hydrophobic agent is lacquer wax and trifluoropropyl methyl silicone oil in a mass ratio of 1:2, and the emulsifier is glycerol monostearate;

[0066] The effervescent agent comprises the following raw materials in parts by mass: 15 parts of acid source, 15 parts of alkali source, 60 parts of modified composite fiber, and 0.1 parts of surfactant, the acid source is citric acid, the alkali source is sodium bicarbonate, and the surfactant is sodium dodecyl sulfate;

[0067] The preparation method of the modified composite fiber comprises the following steps:

[0068] The composite fiber is subjected to beating treatment, the slurry of the composite fiber is mixed with a silver sulfate solution, and the modified composite fiber is obtained after drying; wherein the composite fiber is kapok fiber and soybean fiber in a mass ratio of 1:5;

[0069] The preparation method of the effervescent agent comprises the following steps:

[0070] (1) The modified composite fiber, water, sodium bicarbonate, and sodium dodecyl sulfate are mixed to granulate, dried at 80°C, sieved, and 500-mesh powder is obtained; wherein the amount of water added is 3 times that of the modified composite fiber;

[0071] (2) The citric acid is made into 500-mesh powder;

[0072] (3) The powders obtained in steps (1) and (2) are mixed to obtain the effervescent agent;

[0073] The preparation method of the breathable bottom film for a paper diaper comprises the following steps:

[0074] The polylactic acid, modified biological polysaccharide, and modified composite fiber are mixed, extruded at 180°C, subjected to stretching treatment, cooled, and a bottom film is obtained, glue is sprayed on the surface of the bottom film, and then the effervescent agent is covered on the glue-sprayed surface of the bottom film, and the breathable bottom film for a paper diaper is obtained after drying.

[0075] Example 4

[0076] Example 4 differs from Example 1 in that the amount of biological polysaccharide is unchanged, and the mass ratio of chitosan, hemicellulose, and soap husk gum is 1:3:0.8.

[0077] Example 5

[0078] Example 5 differs from Example 1 in that the amount of the added biological polysaccharide is unchanged, and the mass ratio of chitosan, hemicellulose and soapberry gum is 3:0.8:1.

[0079] Example 6

[0080] Example 6 differs from Example 1 in that the amount of the added hydrophobic agent is unchanged, and no lacquer wax is added, and an equal amount of trifluoropropyl methyl silicone oil is used to make up the missing amount.

[0081] Example 7

[0082] Example 7 differs from Example 1 in that the amount of the added hydrophobic agent is unchanged, and no trifluoropropyl methyl silicone oil is added, and an equal amount of lacquer wax is used to make up the missing amount.

[0083] Comparative Example 1

[0084] Comparative Example 1 differs from Example 1 in that the amount of the added biological polysaccharide is unchanged, and no chitosan is added, and the mass ratio of hemicellulose and soapberry gum is 1:0.8 to make up the missing amount.

[0085] Comparative Example 2

[0086] Comparative Example 2 differs from Example 1 in that the amount of the added biological polysaccharide is unchanged, and no hemicellulose is added, and the mass ratio of chitosan and soapberry gum is 3:0.8 to make up the missing amount.

[0087] Comparative Example 3

[0088] Comparative Example 3 differs from Example 1 in that the amount of the added biological polysaccharide is unchanged, and no soapberry gum is added, and the mass ratio of chitosan and hemicellulose is 3:1.

[0089] Comparative Example 4

[0090] Comparative Example 4 differs from Example 1 in that no hydrophobic agent is added to the modified biological polysaccharide, and an equal amount of emulsifier is used to make up the missing amount.

[0091] Comparative Example 5

[0092] Comparative Example 5 differs from Example 1 in that the modified composite fiber in the effervescent agent is replaced by PVP.

[0093] Comparative Example 6

[0094] Comparative Example 6 differs from Example 1 in that the preparation method of the breathable bottom film for the diaper, comprising the following steps: mixing polylactic acid, modified biological polysaccharide, modified composite fiber and effervescent agent, extruding and molding, then stretching, cooling to obtain the breathable bottom film.

[0095] Performance test

[0096] The bottom film samples of Examples 1-7 and Comparative Examples 1-6 were tested as follows:

[0097] 1. Waterproofness test

[0098] The hydrostatic pressure value of the sample was tested according to GB / T 4744-2013 "Textiles - Determination and testing of waterproofness - Hydrostatic pressure method". The data is shown in Table 1. The greater the hydrostatic pressure value, the better the waterproofness of the sample.

[0099] 2. Air permeability and moisture permeability test

[0100] Moisture permeability: determined according to GB / T 12704-2009 "Textiles - Determination of moisture permeability - Cup method: A method", and the data is shown in Table 1.

[0101] Air permeability: determined according to GB / T 5453-1997 "Textiles - Determination of air permeability of fabrics", and the data is shown in Table 1. The higher the moisture permeability and air permeability, the better the air permeability and moisture permeability of the sample.

[0102] 3. Mechanical property test

[0103] The tensile strength of the sample was tested according to GB / T 3923.1-1997 "Textiles - Determination of breaking force and elongation of fabrics - Strip method", and the specific data is shown in Table 1. The greater the tensile strength, the higher the mechanical strength and durability of the bottom film.

[0104] Table 1 Test results of samples in each group

[0105] Group hydrostatic pressure value / kPa Moisture permeation amount / g.m -2 , 24h]] air permeability / (mm / s) tensile strength / N Example 1 40.70 9053 36.95 713 Example 2 40.38 8906 36.16 687 Example 3 40.65 8993 36.43 706 Example 4 36.15 8571 32.96 679 Example 5 36.08 8567 32.52 660 Example 6 32.06 7288 32.31 627 Example 7 31.78 7264 31.94 620 Comparative Example 1 28.80 6597 24.61 597 Comparative Example 2 28.96 6685 24.88 582 Comparative Example 3 28.74 6589 24.58 590 Comparative Example 4 25.74 9134 38.45 590 Comparative Example 5 31.45 7205 28.86 585 Comparative Example 6 31.17 6170 21.53 573

[0106] From Table 1, combined with the data of Example 1 and Examples 4-5, it can be seen that the waterproofness, air permeability and mechanical strength of Examples 4-5 are lower than those of Example 1, which may be because the mass ratio of the biological polysaccharides affects the hydrophobic modification effect, the water resistance becomes worse, and it is easier to be penetrated by water, and at the same time it may also cause the air permeable microporous structure to be damaged or not smooth, and the air permeability decreases. Therefore, when the mass ratio of chitosan, hemicellulose and soap husk gum is (2-4): 1:(0.5-1), the waterproofness, air permeability and mechanical strength of the bottom film are at a relatively optimal level.

[0107] From the data of Example 1, Example 6-7 and Comparative Example 4, it can be seen that the addition of the hydrophobic agent and the specific selection of the hydrophobic agent are important parameters affecting the water resistance, air permeability and mechanical strength of the base film. Without the addition of the hydrophobic agent, although the air permeability is good, the water resistance and mechanical strength of the base film are greatly reduced. In Example 6-7, only one kind of hydrophobic agent is added, and the performance is also poorer than that of Example 1. This may be because the hydrophobic layer formed by the lacquer wax on the surface of the biological polysaccharide blocks the liquid water, but the hydrophobic modification only acts on the surface groups of the biological polysaccharide, without damaging the internal natural porous structure. The flexibility of the trifluoropropyl methyl silicone oil helps to maintain the softness of the base film, and avoids the decrease of air permeability due to excessive densification. Therefore, the lacquer wax and the trifluoropropyl methyl silicone oil synergistically improve the water resistance, air permeability and mechanical strength of the base film.

[0108] From the data of Example 1 and Comparative Examples 1-3, it can be seen that Comparative Examples 1-3 respectively lack one kind of biological polysaccharide, so that the barrier property, hydrophobic modification and tensile strength effect of the base film are incomplete, and the water resistance and mechanical strength are not as good as that of Example 1. The incomplete biological polysaccharide affects the formation and distribution of the air permeable microporous structure of the base film, and the air permeability is poor.

[0109] From the data of Example 1 and Comparative Example 5, it can be seen that the carrier of the effervescent agent in Comparative Example 5 is PVP, and the performance of the base film is lower than that of Example 1. This may be because the barrier property and hydrophobicity of PVP are not as good as those of the modified composite fiber, so that the water resistance is reduced. The air permeability of PVP is also poor, which affects the overall air permeability of the base film. At the same time, the mechanical strength of PVP is lower than that of the modified composite fiber, and the tensile strength is weakened. Therefore, the modified composite fiber is selected in the present application to simultaneously undertake the functions of strengthening, effervescent agent carrier and antibacterial, avoiding multi-layer compounding, and improving the water resistance, air permeability and mechanical strength of the base film.

[0110] From the data of Example 1 and Comparative Example 6, it can be seen that the effervescent agent is directly extruded in Comparative Example 6, and the high temperature may affect the stability of the effervescent agent, thereby affecting the performance of the base film. Therefore, the dry compounding process and the positioning spraying of the effervescent agent are crucial to the uniformity of the performance, and direct mixing of the effervescent agent will cause performance fluctuation.

[0111] In summary, the air permeable base film of the present application has good water resistance, barrier property, air permeability, antibacterial property and certain mechanical strength, increases the comfort, safety and use performance of the diaper, and can meet the demand of adult diaper base film for multifunctionality and reliability.

[0112] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A breathable bottom film for diapers, characterized in that, The raw materials include the following components by mass fraction: polylactic acid 40-60 parts, modified biological polysaccharide 15-30 parts, effervescent agent 10-20 parts, and modified composite fiber 10-20 parts; wherein the modified biological polysaccharide includes the following components by mass fraction: biological polysaccharide 30-50 parts, hydrophobic agent 10-15 parts, and emulsifier 1-3 parts, the biological polysaccharide is chitosan, hemicellulose, and soap gellan gum, the mass ratio of the chitosan, hemicellulose, and soap gellan gum is (2-4):1:(0.5-1), the hydrophobic agent is lac wax and trifluoropropyl methyl silicone oil with a mass ratio of 1:(0.5-2), the emulsifier is glycerol monostearate; the effervescent agent includes the following components by mass fraction: 10-15 parts of acid source, 10-15 parts of alkali source, 40-60 parts of modified composite fiber, and 0.05-0.1 parts of surfactant; The preparation method of the modified composite fiber includes the following steps: The composite fiber is subjected to beating treatment, the slurry of the composite fiber is mixed with a silver sulfate solution, and the modified composite fiber is obtained after drying; wherein the composite fiber is kapok fiber and soybean fiber, and the mass ratio of the kapok fiber to the soybean fiber is 1:(3-5); The preparation method of the breathable bottom film for the paper diaper includes the following steps: The polylactic acid, the modified biological polysaccharide, and the modified composite fiber are mixed, and after extrusion molding, the bottom film is obtained after stretching treatment and cooling; then glue is sprayed on the surface of the bottom film, and the effervescent agent is covered on the glue-sprayed surface of the bottom film, and the breathable bottom film for the paper diaper is obtained after drying.

2. The breathable backsheet for a diaper according to claim 1, wherein In the preparation method of the modified composite fiber, the addition amount of the silver sulfate solution is 5-6 times of the total mass of the composite fiber, and the mass concentration of the silver sulfate solution is 40-60%; the soaking time is 1-3 h.

3. The breathable backsheet for a diaper according to claim 1, wherein In the preparation method of the breathable bottom film for the paper diaper, the temperature of the extrusion molding is 150-180℃.

4. The breathable backsheet for a diaper according to claim 1, wherein The preparation raw materials of the effervescent agent are selected from at least one of (I)-(III): (I) the acid source is citric acid; (II) the alkali source is sodium bicarbonate; (III) the surfactant is sodium dodecyl sulfate.

5. The breathable backsheet for a diaper according to claim 4, wherein The preparation method of the effervescent agent includes the following steps: (1) the modified composite fiber, water, sodium bicarbonate, and sodium dodecyl sulfate are mixed to granulate, dried, sieved, and a powder with a particle size of 300-500 μm is obtained; (2) citric acid is prepared into a powder with a particle size of 300-500 μm; (3) the powders obtained in steps (1) and (2) are mixed to obtain the effervescent agent.

6. The breathable backsheet for a diaper according to claim 5, wherein In step (1) of the preparation method of the effervescent agent, the addition amount of water is 2-3 times of the modified composite fiber; and the drying temperature is 60-80℃.

7. The breathable bottom film for the paper diaper in the preparation of adult paper diapers according to any one of claims 1-6.