Preparation process and application of a dry and pure cotton non-woven fabric

Abstract

The present invention relates to the technical field of non-woven fabrics, and provides a preparation process and application of a dry and pure cotton non-woven fabric, which solves the problem that the existing disposable sanitary products have an obvious sense of dampness and poor dryness and comfort when using a pure cotton surface layer. The method comprises the following steps: (1) Preparation of a finishing solution: The finishing solution comprises raw materials in the following mass percentages: 5-20% of an emulsifier, 0.8-1.6% of an antibacterial agent, 0.4-2% of a semi-water repellent, 0.1-0.5% of a synergist, 0.05-0.2% of a penetrant, and the balance being deionized water; (2) Coating; (3) Drying.

Description

Technical Field

[0001] The present invention relates to the technical field of non-woven fabrics, and particularly to a preparation process and application of a dry and comfortable pure cotton non-woven fabric. Background Art

[0002] Disposable sanitary products such as sanitary napkins, diapers, pull-up pants, etc. are composed of multiple layers. The absorption area mainly includes a surface layer, a diversion layer, an absorption core, and a bottom film from the inside to the outside. As the material directly contacting the user's skin, the surface layer directly affects the wearing comfort of the product.

[0003] Currently, the surface layers used in disposable sanitary products on the market are mainly divided into the following three types: (1) Dry surface layer. The dry surface layer is composed of a PE film with special micropores, commonly known as a PE punched film. Its characteristics are good absorbency and low rewetting, which can keep the front side of the surface layer dry. However, its wearing comfort is poor, and it is prone to cause skin allergies during use, which is not friendly to sensitive skin. (2) Soft cotton surface layer. The soft cotton surface layer is a chemical fiber non-woven fabric made from polypropylene pellets through a series of processes such as high-temperature melting, spinning, web laying, and hot pressing. After chemical processing, it has a soft touch like cotton, is not only soft and breathable but also has a certain dryness, so it is quite popular among manufacturers. However, this material also belongs to chemical fibers, which may increase the probability of allergies and pose a risk of sensitization. (3) Pure cotton surface layer. The pure cotton surface layer is mainly a pure cotton non-woven fabric made from cotton fibers, which has the characteristics of strong water absorption, good air permeability, softness and skin-friendliness, and no irritation, and is deeply loved by consumers. However, the moisture absorption of pure cotton non-woven fabric is better than its moisture conductivity, and its water absorption and retention ability is strong. Once wetted by liquid, it is easy for the surface layer to absorb more liquid, resulting in high humidity and poor dryness. Moreover, a humid environment is also prone to breeding bacteria, leading to other health problems.

[0004] To improve the dryness and comfort of the pure cotton surface layer and reduce its damp feeling, industry insiders have done a lot of research work. For example, Chinese Patent No. CN201711248649.5 discloses a dry sanitary napkin, and a water-repellent finishing agent is sprayed on the surface layer. The water-repellent finishing agent is composed of the following raw materials in parts by weight: 1-3 parts of octadecyl dimethyl tertiary amine, 0.5-3.5 parts of dimethyl silicone oil, 3-7 parts of glycerol, 0.5-3.5 parts of surfactant, 0.1-0.5 parts of cross-linking agent, 0.5-3.5 parts of acrylic acid, and 95-105 parts of water. This dry sanitary napkin improves the hydrophobicity of the surface layer and the damp feeling of the surface layer by adding a water-repellent finishing agent to the surface layer material, so as to achieve the effect of dryness and comfort. However, if the water-repellent effect of the treated surface layer is strong, it often leads to a slower penetration speed of menstrual blood, which is not conducive to improving dryness.

[0005] Chinese Patent No. CN202022125876.2 discloses a sanitary napkin with a semi-water-repellent fabric, including a sanitary napkin body and winglets. The sanitary napkin body includes: a semi-water-repellent layer made of a mesh cotton material; an absorbent cotton layer disposed below the semi-water-repellent layer; a diversion layer disposed between the semi-water-repellent layer and the absorbent cotton layer; and a bottom film disposed below the absorbent cotton layer, and the bottom film is made of a waterproof and breathable material. This solution uses a mesh cotton material to make the semi-water-repellent layer. The mesh cotton material is a spunlace non-woven fabric made of organic pure cotton. Although it is soft, comfortable and has strong hygroscopicity as the surface layer, its moisture conductivity is poor. Women's menstrual blood cannot quickly penetrate into the internal absorbent cotton layer, making it difficult to achieve the actual effect of semi-water repellency. Summary of the Invention

[0006] Therefore, in view of the above, the present invention provides a preparation process and application of a dry pure cotton non-woven fabric to solve the problem that there is an obvious sense of dampness and poor dry comfort when using a pure cotton surface layer in existing disposable sanitary products.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A preparation process of a dry pure cotton non-woven fabric includes the following steps:

[0009] (1) Preparation of the finishing liquid

[0010] The finishing liquid includes raw materials in the following mass percentages: emulsifier 5-20%, antibacterial agent 0.8-1.6%, semi-water repellent 0.4-2%, synergist 0.1-0.5%, penetrant 0.05-0.2%, and the balance is deionized water;

[0011] Among them, the semi-water repellent is prepared according to the following steps:

[0012] Add polypropylene oxide ether diol, polyethylene glycol, and dibutyltin dilaurate into the reaction kettle. Under a nitrogen atmosphere, heat up to 50-60°C, dropwise add diisocyanate, and then heat up to 80-90°C and stir and react for 2-4 hours; after the reaction is completed, cool down to 70-80°C, add 2,3-dihydroxy-1-butene, and react for 1-3 hours; then add butanone oxime and continue to react until the content of isocyanate groups is below 0.5%; cool down to below 30°C, then adjust the pH value to 7-8, add deionized water for emulsification to obtain a polyurethane emulsion; add isobornyl methacrylate and 2-hydroxyethyl acrylate to the polyurethane emulsion according to a mass ratio of 1:0.7-0.8, fully stir and mix evenly, then add an initiator for free radical polymerization reaction to obtain the semi-water repellent;

[0013] (2) Coating

[0014] The finishing liquid obtained in the above steps is coated on the surface of the corrugated pure cotton non-woven fabric by impregnation, and the liquid carrying rate is controlled to be 114-124%;

[0015] (3) Drying

[0016] The coated corrugated pure cotton non-woven fabric is subjected to drying and forming treatment, and the drying temperature is controlled to be 110-130 °C, and then it is wound up to obtain the dry pure cotton non-woven fabric.

[0017] A further improvement is that: the functionality of the polypropylene glycol ether diol is 2, and the molecular weight is 2000-3000; the number average molecular weight of the polyethylene glycol is 200-600.

[0018] A further improvement is that: the molar ratio of the isocyanate group in the diisocyanate to the hydroxyl groups contained in the polypropylene glycol ether diol and the polyethylene glycol is 1:1.2-1.8.

[0019] A further improvement is that: the addition amount of the dibutyltin dilaurate is 100-200 ppm of the total mass of the polypropylene glycol ether diol, the polyethylene glycol, and the diisocyanate; the addition amount of the 2,3-dihydroxy-1-butene is 5-10% of the total mass of the polypropylene glycol ether diol, the polyethylene glycol, and the diisocyanate.

[0020] A further improvement is that: the mass ratio of the total mass of the isobornyl methacrylate and 2-hydroxyethyl acrylate to the solid content in the polyurethane emulsion is 0.8-1.5:1.

[0021] A further improvement is that: the diisocyanate is any one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and lysine diisocyanate.

[0022] A further improvement is that: the antibacterial agent is prepared according to the following steps:

[0023] 4-(2,3-epoxypropyl)morpholine and the haloalkane are added to the organic solvent according to a molar ratio of 1:1.1-1.3, and after mixing evenly, the temperature is raised to 70-90 °C, and the mixture is stirred and reacted for 48-96 h, cooled to room temperature, and the unreacted haloalkane is removed to obtain intermediate A, and the haloalkane is a bromide or chloride of a saturated aliphatic hydrocarbon with 10-16 carbon atoms;

[0024] Intermediate A and 1-amino-5-hexene are added to dimethyl sulfoxide, and at the same time, an inhibitor and a first catalyst are added, and the mixture is stirred and reacted at 30-50 °C for 5-10 h. After the reaction is completed, it is filtered, washed, and concentrated under reduced pressure to obtain intermediate B;

[0025] Dissolve polymethylhydrogensiloxane, intermediate B, p-methoxyphenol, and the second catalyst in toluene solvent, and stir and react at 80 - 100 °C for 4 - 6 h. After the reaction is completed, filter, wash, concentrate under reduced pressure, and extract to obtain the antibacterial agent.

[0026] A further improvement is that the first catalyst is bismuth chloride, and the addition amount is 2 - 6% of the total mass of intermediate A and 1-amino-5-hexene.

[0027] A further improvement is that the molar ratio of intermediate A to 1-amino-5-hexene is 1:1.1 - 1.3, and the addition amount of the polymerization inhibitor is 0.05 - 0.15% of the total mass of intermediate A and 1-amino-5-hexene.

[0028] A further improvement is that the molecular weight of the polymethylhydrogensiloxane is 5000 - 20000, the hydrogen content is 0.3 - 1.2 wt%, and the molar ratio of the silicon-hydrogen bond in the polymethylhydrogensiloxane to the carbon-carbon double bond in intermediate B is 1:0.8 - 1.

[0029] A further improvement is that the addition amount of p-methoxyphenol is 0.03 - 0.1% of the total mass of polymethylhydrogensiloxane and intermediate B; the second catalyst is a platinum-based catalyst, and its dosage is 40 - 80 ppm of the total mass of polymethylhydrogensiloxane and intermediate B.

[0030] The present invention also provides the application of the dry cotton non-woven fabric obtained by the above preparation process of the dry cotton non-woven fabric in disposable sanitary products, specifically applied to the surface layer of disposable sanitary products.

[0031] By adopting the foregoing technical solutions, the beneficial effects of the present invention are:

[0032] Cotton non-woven fabric has strong hydrophilicity. When used as the surface layer of disposable sanitary products, the sense of dampness is very obvious, which affects the dry and comfortable experience of users. Therefore, it is necessary to perform water-repellent treatment on the cotton non-woven fabric. Traditional water-repellent agents represented by fluorine-containing compounds can endow the non-woven fabric with excellent water-repellent effects, but this is likely to cause the blood seepage rate to slow down, which is not conducive to improving the dryness. In addition, organofluorine water-repellent agents have certain bioaccumulation and toxicity during synthesis and use, which pose certain hazards to human health and the environment; at the same time, they are expensive, resulting in higher production and use costs.

[0033] The present application optimizes the formulation of the finishing liquid and uses it to perform coating finishing on pure cotton spunlace non-woven fabric, reducing the hydrophilicity of the pure cotton spunlace non-woven fabric and achieving the effect of balancing hydrophilic and hydrophobic capabilities, that is, the semi-water-repellent effect. Specifically, the present invention forms a semi-water-repellent agent with a special main chain structure and side chain structure by adjusting the types, contents, and molecular structures of the synthetic raw materials, thereby realizing the semi-water-repellent effect of the non-woven fabric. First, a polyurethane main chain with special soft and hard molecular chain segments is formed by using a large molecular weight polypropylene glycol ether diol and a low molecular weight polyethylene glycol in a specific ratio and cooperating with diisocyanate, which has the characteristics of good flexibility and high bonding strength; secondly, carbon-carbon double bonds are introduced into the side chain of the polyurethane by reacting with 2,3-dihydroxy-1-butene; finally, by using the carbon-carbon double bonds in the polyurethane molecular structure, polymerization reactions are carried out with two specific acrylate monomers to increase the content of hydrophobic groups in the polyurethane structure. When applied to non-woven fabric, it can effectively reduce its surface energy and improve the hydrophobicity of the non-woven fabric. The main chain structure and side chain structure of the semi-water-repellent agent determine the degree of its water-repellent effect, achieving the best hydrophilic-hydrophobic balance state, which can not only prevent the non-woven fabric from being wetted by liquid, but also does not hinder the infiltration and absorption of liquid.

[0034] The roll coating method has certain requirements for the viscosity of the finishing liquid used, and the coating amount is large, and the coating uniformity is relatively poor. The present invention uses the impregnation method to perform post-finishing on pure cotton spunlace non-woven fabric, which well solves the above defects. In addition, the impregnation process can observe the impregnation situation in real time and adjust the process parameters in a timely manner; at the same time, it can also better control the coating amount and find the balance point of the dryness performance.

[0035] During the use of disposable sanitary products such as sanitary napkins and diapers, the humid and stuffy environment creates favorable conditions for the growth of bacteria, which may cause skin problems or gynecological diseases. The present application adds a self-made antibacterial agent to the finishing liquid, which can well solve the above problems. During the preparation process, first, the quaternization reaction of 4-(2,3-epoxypropyl)morpholine and haloalkane is used to obtain a quaternary ammonium salt (i.e., intermediate A), and the ether bond in the quaternary ammonium salt structure can improve the flexibility of the non-woven fabric.

[0036] The dimethyl chain segments and siloxane bonds in the polysiloxane polymer compound can rotate freely around the macromolecular siloxane chain, and the siloxane bond angle is large, so the non-woven fabric after finishing is very soft. However, siloxane has a low surface tension, and after finishing, it will give the non-woven fabric an excellent water-repellent effect. The present application obtains an intermediate B containing hydroxyl and amino active groups through a ring-opening reaction between intermediate A and 1-amino-5-hexene, and introduces a carbon-carbon double bond into the molecular structure; then a hydrosilylation reaction is carried out with polymethyl hydrogen siloxane to introduce a hydrophilic group on the side chain of siloxane, solving the problem that the softness and hydrophilicity of existing polysiloxane compounds cannot be taken into account. The amino and hydroxyl groups in the molecular structure of the antibacterial agent can interact with the active groups in the structure of the semi-water-repellent agent, as well as the hydroxyl, carboxyl and other groups on the surface of the cotton fiber, so that the effective ingredients of the finishing liquid are firmly adsorbed on the cotton fiber. The antibacterial agent has a positive charge, while the cotton fiber has a certain negative charge. Through the combination of positive and negative ionic bonds, the antibacterial agent can be adsorbed on the surface of the non-woven fabric.

[0037] Non-ionic polyurethane surfactants have excellent properties such as thickening, emulsification, and solubilization. The inventors found during the research process that non-ionic polyurethane surfactants can be used as synergists and cooperate with other components to improve the infiltration and diffusion properties of non-woven fabrics.

[0038] The wavy design of dry pure cotton non-woven fabric has the following technical effects when applied to disposable sanitary products: (1) it can reduce the contact area with the user and increase the breathability; (2) it can increase the contact area with the liquid and accelerate the infiltration speed; (3) it can reduce the back-seepage amount and reduce the feeling of dampness. DETAILED DESCRIPTION

[0039] The following will describe the implementation methods of the present invention in detail in conjunction with specific embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0040] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the reagents and products used are all commercially available. The sources, trade names and components of the reagents used are indicated when they first appear.

[0041] Example 1

[0042] A preparation process of a dry pure cotton nonwoven fabric comprises the following steps:

[0043] (1) Preparation of wavy cotton nonwoven fabric

[0044] The pure cotton nonwoven fabric is prepared into a wavy pure cotton nonwoven fabric by a wavy pattern plate roller;

[0045] (2) Preparation of finishing liquid

[0046] The finishing liquid comprises raw materials in the following mass percentages: Tween-81 5%, antibacterial agent 0.8%, semi-water repellent 0.4%, synergist 0.1%, JFC penetrant 0.05%, and the balance is deionized water. The synergist is a non-ionic polyurethane surfactant, which can be a commercially available product or self-made. In this embodiment, it is prepared from diphenylmethane diisocyanate (MDI), castor oil, polyethylene glycol, and methanol. The preparation method is a prior art, and specific details can be found in the journal literature (Shi Yuanchang, Wu Youshi, Zhang Li. Synthesis and properties of non-ionic polyurethane surfactants [J]. Polymer Materials Science and Engineering, 2003, 19(6): 69-71.).

[0047] Among them, the semi-water repellent is prepared according to the following steps:

[0048] Add polypropylene glycol ether diol, polyethylene glycol, and dibutyltin dilaurate into the reaction kettle. Under a nitrogen atmosphere, heat up to 50°C, dropwise add isophorone diisocyanate, then heat up to 80°C and stir and react for 4 h; after the reaction is completed, cool down to 70°C, add 2,3-dihydroxy-1-butene and react for 1 h; then add butanone oxime and continue to react until the content of isocyanate group is below 0.5%; cool down to below 30°C, then adjust the pH value to 7-8, add deionized water for emulsification to obtain a polyurethane emulsion; add isobornyl methacrylate and 2-hydroxyethyl acrylate into the polyurethane emulsion according to the mass ratio of 1:0.7, fully stir and mix evenly, then add ammonium persulfate and carry out a free radical polymerization reaction to obtain the semi-water repellent;

[0049] The polypropylene glycol ether diol has a functionality of 2 and a molecular weight of 2000; the number average molecular weight of the polyethylene glycol is 600. The molar ratio of the isocyanate group in the isophorone diisocyanate to the hydroxyl groups contained in the polypropylene glycol ether diol and the polyethylene glycol is 1:1.2. The addition amount of the dibutyltin dilaurate is 100 ppm of the total mass of the polypropylene glycol ether diol, polyethylene glycol, and diisocyanate. The addition amount of the 2,3-dihydroxy-1-butene is 5% of the total mass of the polypropylene glycol ether diol, polyethylene glycol, and diisocyanate. The mass ratio of the total mass of the isobornyl methacrylate and 2-hydroxyethyl acrylate to the solid content in the polyurethane emulsion is 0.8:1. The addition amount of the ammonium persulfate is 1% of the total mass of the isobornyl methacrylate and 2-hydroxyethyl acrylate;

[0050] The antibacterial agent is prepared according to the following steps:

[0051] a1. Preparation of Intermediate A: 4-(2,3-epoxypropyl)morpholine and 1-bromodecane were added to toluene at a molar ratio of 1:1.1. After mixing evenly, the temperature was raised to 70 °C, and the mixture was stirred and reacted for 96 h. Then it was cooled to room temperature, and the unreacted 1-bromodecane was removed to obtain Intermediate A;

[0052] a2. Preparation of Intermediate B: Intermediate A and 1-amino-5-hexene were added to dimethyl sulfoxide. At the same time, 2,6-di-tert-butyl-p-cresol and bismuth chloride were added. The mixture was stirred and reacted at 30 °C for 10 h. After the reaction was completed, it was filtered, washed, and concentrated under reduced pressure to obtain Intermediate B. The molar ratio of Intermediate A to 1-amino-5-hexene was 1:1.1. The addition amount of 2,6-di-tert-butyl-p-cresol was 0.05% of the total mass of Intermediate A and 1-amino-5-hexene, and the addition amount of bismuth chloride was 2% of the total mass of Intermediate A and 1-amino-5-hexene;

[0053] a3. Preparation of Antibacterial Agent: Polymethylhydrogensiloxane, Intermediate B, p-methoxyphenol, and the second catalyst were dissolved in toluene solvent. The mixture was stirred and reacted at 80 °C for 6 h. After the reaction was completed, it was filtered, washed, concentrated under reduced pressure, and extracted to obtain the antibacterial agent. The molecular weight of the polymethylhydrogensiloxane was 5000, and the hydrogen content was 0.3 wt%. The molar ratio of the silicon-hydrogen bond in the polymethylhydrogensiloxane to the carbon-carbon double bond in Intermediate B was

[0054] 1:0.8. The addition amount of p-methoxyphenol was 0.03% of the total mass of polymethylhydrogensiloxane and Intermediate B; the second catalyst was chloroplatinic acid, and its dosage was 40 ppm of the total mass of polymethylhydrogensiloxane and Intermediate B;

[0055] (3) Coating

[0056] The finishing liquid obtained in the above steps was coated on the surface of the corrugated pure cotton non-woven fabric by impregnation, and the liquid holding rate was controlled at 124%;

[0057] (4) Drying

[0058] The coated corrugated pure cotton non-woven fabric was subjected to drying and forming treatment, and the drying temperature was controlled at 110 °C. After winding, the dry pure cotton non-woven fabric was obtained.

[0059] In this example, the pure cotton non-woven fabric was pressed into a corrugated shape and then subjected to subsequent processing. The obtained product was applied to the surface layer of disposable sanitary products. However, it is not limited to the corrugated shape, and other patterns can also be used to achieve the corresponding technical effects.

[0060] Example 2

[0061] A preparation process of dry pure cotton non-woven fabric, comprising the following steps:

[0062] (1) Preparation of corrugated pure cotton non-woven fabric

[0063] The corrugated pure cotton non-woven fabric is prepared from pure cotton non-woven fabric through a corrugated pattern roller.

[0064] (2) Preparation of finishing liquid

[0065] The finishing liquid comprises raw materials in the following mass percentages: Span-20 12%, antibacterial agent 1.2%, semi-water repellent 1.2%, non-ionic polyurethane surfactant 0.3%, penetrant JFC 0.12%, and the balance is deionized water.

[0066] Among them, the semi-water repellent is prepared according to the following steps:

[0067] Poly(propylene oxide) ether diol, polyethylene glycol, and dibutyltin dilaurate are added into a reaction kettle. Under a nitrogen atmosphere, the temperature is raised to 55°C, and dicyclohexylmethane diisocyanate is added dropwise. Then the temperature is raised to 85°C and stirred for reaction for 3 h. After the reaction is completed, the temperature is lowered to 75°C, 2,3-dihydroxy-1-butene is added, and the reaction is carried out for 2 h. Then methyl ethyl ketoxime is added, and the reaction continues until the content of isocyanate groups is below 0.5%. The temperature is lowered to below 30°C, then the pH value is adjusted to 7-8, and deionized water is added for emulsification to obtain a polyurethane emulsion. Isobornyl methacrylate and 2-hydroxyethyl acrylate are added to the polyurethane emulsion according to a mass ratio of 1:0.75. After being fully stirred and mixed evenly, methyl ethyl ketone peroxide is added for free radical polymerization reaction to obtain the semi-water repellent.

[0068] The poly(propylene oxide) ether diol has a functionality of 2 and a molecular weight of 3000; the polyethylene glycol has a number average molecular weight of 400. The molar ratio of isocyanate groups in the dicyclohexylmethane diisocyanate to the hydroxyl groups contained in the poly(propylene oxide) ether diol and polyethylene glycol is 1:1.5. The addition amount of dibutyltin dilaurate is 150 ppm of the total mass of the poly(propylene oxide) ether diol, polyethylene glycol, and diisocyanate. The addition amount of 2,3-dihydroxy-1-butene is 8% of the total mass of the poly(propylene oxide) ether diol, polyethylene glycol, and diisocyanate. The mass ratio of the total mass of isobornyl methacrylate and 2-hydroxyethyl acrylate to the solid content in the polyurethane emulsion is 1:1. The addition amount of methyl ethyl ketone peroxide is 0.8% of the total mass of isobornyl methacrylate and 2-hydroxyethyl acrylate.

[0069] The antibacterial agent is prepared according to the following steps:

[0070] a1. Preparation of intermediate A: 4-(2,3-epoxypropyl)morpholine and dodecyl chloride are added to an organic solvent according to a molar ratio of 1:1.2, mixed evenly, heated to 80°C, stirred for reaction for 72 h, cooled to room temperature, and the unreacted dodecyl chloride is removed to obtain intermediate A.

[0071] a2. Preparation of Intermediate B: Add Intermediate A and 1-amino-5-hexene into dimethyl sulfoxide, and simultaneously add hydroquinone and bismuth chloride. Stir and react at 40 °C for 8 h. After the reaction is completed, filter, wash, and concentrate under reduced pressure to obtain Intermediate B. The molar ratio of Intermediate A to 1-amino-5-hexene is 1:1.2. The addition amount of hydroquinone is 0.1% of the total mass of Intermediate A and 1-amino-5-hexene. The addition amount of bismuth chloride is 4% of the total mass of Intermediate A and 1-amino-5-hexene;

[0072] a3. Preparation of the antibacterial agent: Dissolve polymethylhydrosiloxane, Intermediate B, p-methoxyphenol, and the second catalyst in toluene solvent, and stir and react at 90 °C for 5 h. After the reaction is completed, filter, wash, concentrate under reduced pressure, and extract to obtain the antibacterial agent. The molecular weight of the polymethylhydrosiloxane is 10,000, and the hydrogen content is 0.8 wt%. The molar ratio of the silicon-hydrogen bond in the polymethylhydrosiloxane to the carbon-carbon double bond in Intermediate B is

[0073] 1:0.9. The addition amount of p-methoxyphenol is 0.06% of the total mass of polymethylhydrosiloxane and Intermediate B; The second catalyst is Karstedt catalyst, and its dosage is 60 ppm of the total mass of polymethylhydrosiloxane and Intermediate B;

[0074] (3) Coating

[0075] Coat the finishing liquid obtained in the above step on the surface of the corrugated pure cotton non-woven fabric by impregnation, and control the liquid content rate to be 119%;

[0076] (4) Drying

[0077] Conduct drying and forming treatment on the coated corrugated pure cotton non-woven fabric, control the drying temperature to be 120 °C, and wind up to obtain the dry pure cotton non-woven fabric.

[0078] In this example, the pure cotton non-woven fabric is pressed into a corrugated shape and then subjected to subsequent processing. The obtained product is applied to the surface layer of disposable sanitary products. However, it is not limited to the corrugated shape, and other patterns can also be used to achieve the corresponding technical effects.

[0079] Example 3

[0080] A preparation process of a dry pure cotton non-woven fabric, comprising the following steps:

[0081] (1) Preparation of the corrugated pure cotton non-woven fabric

[0082] Prepare the pure cotton non-woven fabric into a corrugated pure cotton non-woven fabric through a corrugated pattern roller;

[0083] (2) Preparation of the finishing liquid

[0084] The finishing liquid comprises raw materials in the following mass percentages: Tween-60 20%, antibacterial agent 1.6%, semi-water repellent 2%, nonionic polyurethane surfactant 0.5%, penetrant JFC 0.2%, and the balance is deionized water;

[0085] Among them, the semi-water repellent is prepared according to the following steps:

[0086] Add polypropylene oxide ether diol, polyethylene glycol, and dibutyltin dilaurate into the reaction kettle. Under a nitrogen atmosphere, heat up to 60°C, dropwise add lysine diisocyanate, then heat up to 80-90°C, and stir and react for 2 h; after the reaction is completed, cool down to 80°C, add 2,3-dihydroxy-1-butene, and react for 3 h; then add butanone oxime, and continue to react until the content of isocyanate groups is below 0.5%; cool down to below 30°C, then adjust the pH value to 7-8, add deionized water for emulsification to obtain a polyurethane emulsion; add isobornyl methacrylate and 2-hydroxyethyl acrylate into the polyurethane emulsion according to a mass ratio of 1:0.8, fully stir and mix evenly, then add lauroyl peroxide, and carry out a free radical polymerization reaction to obtain the semi-water repellent;

[0087] The polypropylene oxide ether diol has a functionality of 2 and a molecular weight of 3000; the number average molecular weight of the polyethylene glycol is 200, the molar ratio of the isocyanate groups in the lysine diisocyanate to the hydroxyl groups contained in the polypropylene oxide ether diol and the polyethylene glycol is 1:1.8, the addition amount of the dibutyltin dilaurate is 200 ppm of the total mass of the polypropylene oxide ether diol, polyethylene glycol, and diisocyanate, the addition amount of the 2,3-dihydroxy-1-butene is 10% of the total mass of the polypropylene oxide ether diol, polyethylene glycol, and diisocyanate, the mass ratio of the total mass of the isobornyl methacrylate and 2-hydroxyethyl acrylate to the solid content in the polyurethane emulsion is 1.5:1, and the addition amount of the lauroyl peroxide is 0.6% of the total mass of the isobornyl methacrylate and 2-hydroxyethyl acrylate;

[0088] The antibacterial agent is prepared according to the following steps:

[0089] a1. Preparation of intermediate A: Add 4-(2,3-epoxypropyl)morpholine and bromohexadecane into an organic solvent according to a molar ratio of 1:1.3, mix evenly, heat up to 90°C, stir and react for 48 h, cool to room temperature, and remove the unreacted bromohexadecane to obtain intermediate A;

[0090] a2. Preparation of Intermediate B: Add Intermediate A and 1-amino-5-hexene into dimethyl sulfoxide, and simultaneously add hydroquinone and bismuth chloride. Stir and react at 50 °C for 5 h. After the reaction is completed, filter, wash, and concentrate under reduced pressure to obtain Intermediate B. The molar ratio of Intermediate A to 1-amino-5-hexene is 1:1.3. The addition amount of hydroquinone is 0.15% of the total mass of Intermediate A and 1-amino-5-hexene. The addition amount of bismuth chloride is 6% of the total mass of Intermediate A and 1-amino-5-hexene;

[0091] a3. Preparation of the antibacterial agent: Dissolve polymethylhydrogensiloxane, Intermediate B, p-methoxyphenol, and the second catalyst in toluene solvent, and stir and react at 100 °C for 4 h. After the reaction is completed, filter, wash, concentrate under reduced pressure, and extract to obtain the antibacterial agent. The molecular weight of the polymethylhydrogensiloxane is 20,000, and the hydrogen content is 1.2 wt%. The molar ratio of the silicon-hydrogen bond in the polymethylhydrogensiloxane to the carbon-carbon double bond in Intermediate B is 1:1. The addition amount of p-methoxyphenol is 0.1% of the total mass of polymethylhydrogensiloxane and Intermediate B; The second catalyst is chloroplatinic acid, and its dosage is 80 ppm of the total mass of polymethylhydrogensiloxane and Intermediate B;

[0092] (3) Coating

[0093] Coat the finishing liquid obtained in the above steps on the surface of the corrugated pure cotton non-woven fabric by impregnation, and control the liquid pick-up rate to be 114%;

[0094] (4) Drying

[0095] Conduct drying and forming treatment on the coated corrugated pure cotton non-woven fabric, control the drying temperature to be 130 °C, and wind up to obtain the dry pure cotton non-woven fabric.

[0096] In this example, the pure cotton non-woven fabric is pressed into corrugations and then subjected to subsequent processing. The obtained product is applied to the surface layer of disposable sanitary products. However, it is not limited to corrugations, and other patterns can also be used to achieve the corresponding technical effects.

[0097] Performance testing

[0098] The dry cotton non-woven fabrics prepared in Examples 1 to 3 were tested for antibacterial properties, wicking and penetration properties, penetration time, and diffusion performance. The untreated cotton non-woven fabric was used as Control Group I, and the fully water-repellent treated cotton non-woven fabric was used as Control Group II. The test results are shown in Table 1. Among them, the test method for penetration time is as follows: ① Cut a non-woven fabric material of appropriate width and length as a set of experiments. The non-woven fabric material is not allowed to have obvious creases and defects; ② Place the standard core on the inspection table, place the test sample closely on the standard core, and ensure that the test surface is flat; ③ Take a certain amount of standard synthetic liquid, perpendicular to the surface of the test sample, drop it on the surface of the test sample, and record the disappearance time of the standard synthetic liquid on the surface of the test sample; ④ Repeat the above steps to complete the penetration performance test. The shorter the penetration time, the worse the dryness. The test method for wicking and penetration properties is as follows: ① Adjust the angle of the tester, adjust the position and height of the lower opening of the funnel. The lower opening of the funnel faces the operator, and pour an appropriate amount of test solution into the funnel and rinse the funnel twice; ② Place the standard core on the inclined panel, place the test sample on the standard core, and the use surface faces up; ③ Use a pipette to accurately transfer a certain amount of test solution into the funnel, then quickly open the funnel valve to the maximum, so that the solution freely flows onto the surface of the test sample and flows down along the inclined plane. After flowing out, close the funnel valve, catch the flowing liquid with a beaker, weigh and record the wicking amount; ⑤ Repeat the above steps, and take the average value of 5 test samples as the measurement result. The test method for diffusion performance is as follows: ① Lay a layer of test sample on the standard core, with the use surface of the test sample facing up, and keep it flat above the filter paper; ② Measure a certain amount of standard synthetic liquid, and drop the standard synthetic liquid at the same position in the middle of the filter paper. After standing for a period of time, measure the maximum diffusion length (L) and maximum diffusion width (W) of the liquid on the surface layer of the test sample; ③ Repeat the above steps for testing, and take the average value as the measurement result.

[0099] Table 1

[0100]

[0101] Note: - represents no antibacterial effect.

[0102] Comparative Example 1

[0103] The difference from Example 1 is that the non-ionic polyurethane surfactant is not added to the finishing solution. The performance test was carried out on the dry cotton non-woven fabric prepared in this comparative example. The results show that the penetration time is 0.47 s, the diffusion length is 40 mm, and the diffusion width is 32 mm.

[0104] Comparative Example 2

[0105] The difference from Example 1 lies in that the liquid carrying rate in the coating process of step (2) is controlled at 110%. Performance tests were carried out on the dry and comfortable pure cotton non-woven fabric obtained in this comparative example. The results showed that the penetration time was 0.43 s, the diffusion length was 42 mm, the diffusion width was 35 mm, and no liquid slipped out.

[0106] Comparative Example 3

[0107] The difference from Example 1 lies in that the liquid carrying rate in the coating process of step (2) is controlled at 130%. Performance tests were carried out on the dry and comfortable pure cotton non-woven fabric obtained in this comparative example. The results showed that the penetration time was 15 s, the diffusion length was 30 mm, the diffusion width was 25 mm, and the slippage amount was 1 / 2 of the outflowing liquid.

[0108] The inventor also found during the research process that the level of the liquid carrying rate also affects the water repellency effect after coating. When the liquid carrying rate is in the range of 114-124%, good semi-water repellent performance can be imparted to the pure cotton hydroentangled non-woven fabric after coating.

[0109] Using the dry and comfortable pure cotton non-woven fabrics prepared in Examples 1 to 3 as the surface layer, sanitary napkin products were made. The sanitary napkins have a conventional structure, including a sanitary napkin body and wing parts provided on both sides of the sanitary napkin body. The sanitary napkin body sequentially includes a surface layer, a diversion layer, an absorption layer, and a breathable bottom film from top to bottom. Penetration performance tests were carried out on the sanitary napkin products, and the test results are shown in Table 2. Sanitary napkins made of untreated pure cotton non-woven fabric as the surface layer were used as Control Group III, and sanitary napkins made of fully water-repellent treated pure cotton non-woven fabric as the surface layer were used as Control Group IV. Test method for the penetration performance of the finished product: Place the test blood in a burette, and align the liquid discharge port of the burette with the sanitary napkin. Open the piston, start timing when the test liquid is released, and record the time required for the test blood to disappear, that is, the penetration time, and measure the diffusion length and diffusion width of the blood on the surface layer; Weigh the filter paper, cover the product liquid addition point with the known weight filter paper, and place a pressure block, weigh the weight of the filter paper after heavy pressing, and calculate the increased weight of the filter paper (i.e., the re-permeation amount).

[0110] Table 2

[0111] Diffusion length / mm Diffusion width / mm Infiltration time / s Back infiltration amount / g Example 1 76 40 7.2 3.8 Example 2 72 37 7.5 3.4 Example 3 71 35 7.7 3.4 Control group Ⅲ 93 52 4.9 5.3 Control group Ⅳ 46 24 ＞30 2.5

[0112] As recorded above, only the embodiments using the technical content of this creation are provided. Any modifications and changes made by those skilled in the art using this creation fall within the scope of the patent claimed in this creation, rather than being limited to those disclosed in the embodiments.

Claims

1. A preparation process of a dry and pure cotton non-woven fabric, characterized in that: It includes the following steps: (1) Preparation of the finishing liquid The finishing liquid comprises raw materials in the following mass percentages: emulsifier 5-20%, antibacterial agent 0.8-1.6%, semi-water repellent 0.4-2%, synergist 0.1-0.5%, penetrant 0.05-0.2%, and the balance is deionized water; Among them, the semi-water repellent is prepared according to the following steps: Add poly(propylene oxide) ether diol, polyethylene glycol, and dibutyltin dilaurate into a reaction kettle. Under a nitrogen atmosphere, heat up to 50-60°C, dropwise add diisocyanate, then heat up to 80-90°C, and stir and react for 2-4 h; after the reaction is completed, cool down to 70-80°C, add 2,3-dihydroxy-1-butene, and react for 1-3 h; then add butanone oxime and continue to react until the content of isocyanate groups is below 0.5%; cool down to below 30°C, then adjust the pH value to 7-8, add deionized water for emulsification to obtain a polyurethane emulsion; add isobornyl methacrylate and 2-hydroxyethyl acrylate to the polyurethane emulsion according to a mass ratio of 1:0.7-0.8, fully stir and mix evenly, then add an initiator and carry out a free radical polymerization reaction to obtain the semi-water repellent; (2) Coating Coat the finishing liquid obtained in the above steps on the surface of the pure cotton non-woven fabric by dipping, and control the liquor pickup rate to be 114-124%; (3) Drying Carry out a drying and forming treatment on the coated pure cotton non-woven fabric, control the drying temperature to be 110-130°C, and wind up to obtain a dry pure cotton non-woven fabric; The antibacterial agent is prepared according to the following steps: a1. Add 4-(2,3-epoxypropyl)morpholine and haloalkane into an organic solvent according to a molar ratio of 1:1.1-1.3, mix evenly, heat up to 70-90°C, stir and react for 48-96 h, cool to room temperature, and remove the unreacted haloalkane to obtain intermediate A; a2. Add intermediate A and 1-amino-5-hexene into dimethyl sulfoxide, and at the same time add an inhibitor and a first catalyst, stir and react at 30-50°C for 5-10 h, after the reaction is completed, filter, wash, and concentrate under reduced pressure to obtain intermediate B; a3. Dissolve polymethylhydrogensiloxane, intermediate B, p-methoxyphenol, and a second catalyst in toluene solvent, stir and react at 80-100°C for 4-6 h, after the reaction is completed, filter, wash, concentrate under reduced pressure, and extract to obtain the antibacterial agent.

2. The preparation process of a dry and comfortable pure cotton non-woven fabric according to claim 1, characterized in that: The functionality of the poly(propylene oxide) ether diol is 2, and its molecular weight is 2000-3000; the number average molecular weight of the polyethylene glycol is 200-600.

3. The preparation process of a dry and pure cotton non-woven fabric according to claim 1, characterized in that: The molar ratio of the isocyanate groups in the diisocyanate to the hydroxyl groups contained in the poly(propylene oxide) ether diol and the polyethylene glycol is 1:1.2-1.

8.

4. The preparation process of a dry and comfortable pure cotton non-woven fabric according to claim 1, characterized in that: The addition amount of the dibutyltin dilaurate is 100-200 ppm of the total mass of the poly(propylene oxide) ether diol, the polyethylene glycol, and the diisocyanate; the addition amount of the 2,3-dihydroxy-1-butene is 5-10% of the total mass of the poly(propylene oxide) ether diol, the polyethylene glycol, and the diisocyanate.

5. The preparation process of a dry and comfortable pure cotton non-woven fabric according to claim 1, characterized in that: The mass ratio of the total mass of the isobornyl methacrylate and the 2-hydroxyethyl acrylate to the solid content in the polyurethane emulsion is 0.8-1.5:

1.

6. The preparation process of a dry and comfortable pure cotton non-woven fabric according to claim 1, characterized in that: The first catalyst is bismuth chloride, and the addition amount is 2-6% of the total mass of intermediate A and 1-amino-5-hexene.

7. The preparation process of a dry and comfortable pure cotton non-woven fabric according to claim 1, characterized in that: The molar ratio of the intermediate A to 1-amino-5-hexene is 1:1.1-1.3, and the addition amount of the polymerization inhibitor is 0.05-0.15% of the total mass of intermediate A and 1-amino-5-hexene.

8. The preparation process of a dry and pure cotton non-woven fabric according to claim 1, characterized in that: The molecular weight of the polymethylhydrogensiloxane is 5000-20000, and the hydrogen content is 0.3-1.2 wt%, and the molar ratio of the silicon-hydrogen bond in the polymethylhydrogensiloxane to the carbon-carbon double bond of intermediate B is 1:0.8-1.

9. Application of the dry cotton non-woven fabric obtained by the preparation process of the dry cotton non-woven fabric according to any one of claims 1-8 in disposable sanitary products.

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