A microporous breathable fabric, preparation method and application

Abstract

The present invention discloses a microporous breathable fabric, a preparation method and an application, relating to the technical field of fabric treatment. The present invention discloses a preparation method of a microporous breathable fabric, which comprises the following steps: coating a polyurethane coating agent on the surface of a base fabric and then drying to obtain the microporous breathable fabric; the polyurethane coating agent comprises the following raw materials in parts by weight: 100 parts of an organosilicon-modified polyurethane emulsion, 8-11 parts of N,N-dimethylacetamide, 2-2.5 parts of n-octanol, 5-8 parts of a foam stabilizer, and 1-3 parts of a thickener PTF; the organosilicon-modified polyurethane emulsion is obtained by crosslinking polyurethane with silica sol and carboxymethyl cellulose; the polyurethane coating agent prepared with the organosilicon-modified polyurethane emulsion as the base material is coated on the surface of the base fabric, endowing the fabric with high waterproof performance and also having high air permeability and moisture permeability; the microporous breathable fabric prepared in this application is applied in the field of outdoor sportswear, providing a comfortable wearing experience.

Description

Technical Field

[0001] The invention relates to the technical field of fabric processing, and in particular to a microporous breathable fabric, a preparation method and application thereof. Background Art

[0002] In the past few decades, waterproof fabrics made of polyvinyl chloride, polyurethane, chloroprene rubber and various synthetic rubbers have been widely used. They give fabrics excellent waterproof and rainproof properties, but they are not breathable. The moisture constantly emitted by the human body when sweating cannot pass through the waterproof fabric, and a large amount of sweat cannot be discharged in the form of steam, but condenses into water on the inner surface of the clothing, causing sticky, stuffy and other uncomfortable feelings. It is even dangerous to use such non-breathable waterproof fabrics in harsh conditions. For example, if they are made into tents or sleeping bags, they are prone to hypoxia when used; when mountaineers wear them to climb mountains, the condensed sweat in the clothing is easy to freeze and cause frostbite.

[0003] In order to meet the requirements of the comfort function of waterproof fabrics, waterproof and breathable fabrics came into being. Waterproof and breathable clothing is the most widely used outdoor sportswear at present, which can simultaneously meet the different requirements of waterproof, breathable, windproof and warm keeping for the external environment during outdoor sports or leisure sports. In view of the physiological characteristics of high heat generation and high sweat evaporation during outdoor sports, waterproof and breathable fabrics can provide good heat dissipation and air permeability and moisture permeability after strenuous exercise of the human body. In the prior art, the so-called waterproof and breathable means that water (mainly rainwater) cannot penetrate the fabric under a certain pressure, and the sweat emitted by the human body is conducted to the outside world through the fabric in the form of water vapor, and does not condense and accumulate on the surface of the human body or between fabrics. Good moisture permeability is an important manifestation of comfortable clothing. The amount of sweat vapor from the human body varies from person to person, usually 350-600g / m 2 ˙24h, heavy physical labor can reach 12000g / m 2 ˙24h, so the minimum steam permeability of the fabric must reach 2500g / m 2 ˙24h can be said to be breathable. However, the waterproof and breathable fabrics prepared in the prior art are difficult to achieve unity in the two functions of waterproof and breathable. Therefore, preparing a coated fabric that can achieve both waterproof performance and high moisture permeability and breathability is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a microporous breathable fabric, a preparation method and an application thereof, to solve the following technical problems:

[0005] Existing waterproof and breathable fabrics are difficult to achieve high moisture permeability and air permeability while achieving high waterproof performance.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for preparing a microporous breathable fabric, comprising the following steps: coating a polyurethane coating agent on the surface of a base fabric and then drying to obtain the microporous breathable fabric;

[0008] The polyurethane coating agent comprises the following raw materials in parts by weight: 100 parts of organosilicon-modified polyurethane emulsion, 8-11 parts of N,N-dimethylacetamide, 2-2.5 parts of n-octanol, 5-8 parts of foam stabilizer, and 1-3 parts of thickener PTF;

[0009] The method for preparing the organosilicon-modified polyurethane emulsion comprises the following steps:

[0010] Add polyether diol, acetone, dibutyltin dilaurate, diphenylmethane diisocyanate into a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, control the temperature at 55-65 °C, keep the temperature for reaction for 1-3 h, add dimethylolpropionic acid, continue to keep the temperature for reaction for 1-3 h, cool to room temperature, add triethylamine and disperse evenly, then heat up to 55-65 °C, add silica sol crosslinked carboxymethyl cellulose, keep the temperature for 0.5-1 h under stirring conditions, and rotary evaporate to remove acetone to obtain the organosilicon-modified polyurethane emulsion.

[0011] As a further scheme of the present invention: the addition ratio of polyether diol, acetone, dibutyltin dilaurate, diphenylmethane diisocyanate, dimethylolpropionic acid, triethylamine, and silica sol crosslinked carboxymethyl cellulose is 10 g: 50-100 mL: 0.2-0.4 g: 5-10 g: 2-4 g: 0.6-1 g: 2-4 g.

[0012] As a further scheme of the present invention: the method for preparing the silica sol crosslinked carboxymethyl cellulose comprises the following steps:

[0013] S1: Add carboxymethyl cellulose and deionized water into a reaction kettle and disperse evenly, add epichlorohydrin and hydrochloric acid solution, control the temperature at 50-60 °C, keep the temperature for reaction for 12-24 h, wash with ethanol, filter by suction, and dry to obtain component one;

[0014] S2: Add component one and deionized water into a reaction kettle and disperse evenly, add γ-aminopropyltriethoxysilane, control the temperature at 50-60 °C, keep the temperature for reaction for 12-24 h, centrifuge, wash, and dry to obtain component two;

[0015] S3: Add component two, tetraethyl orthosilicate, and absolute ethanol into a reaction kettle and disperse evenly, add deionized water, add hydrochloric acid to adjust the pH to 4-5, control the temperature at 40-45 °C, keep the temperature for reaction for 1-2 h, and obtain the silica sol crosslinked carboxymethyl cellulose.

[0016] As a further solution of the present invention: in S1, the addition ratio of the hydrochloric acid solution is 3-6 mol / L hydrochloric acid aqueous solution; the addition ratios of carboxymethyl cellulose, deionized water, epichlorohydrin, and hydrochloric acid solution are 10 g: 50-100 mL: 2-4 mL: 0.5-1 mL.

[0017] As a further solution of the present invention: in S2, the addition ratios of component one, deionized water, and γ-aminopropyltriethoxysilane are 10 g: 50-100 mL: 0.2-0.4 g.

[0018] As a further solution of the present invention: in S3, the addition ratios of component two, tetraethyl orthosilicate, absolute ethanol, and deionized water are 10 g: 5-10 g: 15-25 mL: 10-20 mL.

[0019] As a further solution of the present invention: the base fabric is any one of cotton spun base fabric, polyester spun base fabric, nylon spun base fabric, cotton and polyester blended base fabric, and cotton and nylon blended base fabric.

[0020] As a further solution of the present invention: the coating amount of the polyurethane coating agent is 5-25 g / m 2 .

[0021] As a further solution of the present invention: the specific steps of drying are: the oven temperature is 90-100 °C, pre-drying for 3 min, the oven temperature is 150-160 °C, and baking for 2-3 min.

[0022] A microporous breathable fabric is made by any one of the above preparation methods.

[0023] The above-mentioned microporous breathable fabric is applied to the field of outdoor sports clothing.

[0024] The beneficial effects of the present invention:

[0025] (1) In this application, carboxymethyl cellulose is used as a raw material. Through the esterification reaction of epichlorohydrin with the carboxyl group of carboxymethyl cellulose, component one is obtained; and by using component one to carry out a nucleophilic substitution reaction with γ-aminopropyltriethoxysilane, component two is obtained; then using component two to co-hydrolyze with tetraethyl orthosilicate to obtain silica sol cross-linked carboxymethyl cellulose; finally, adding the silica sol cross-linked carboxymethyl cellulose to the polyurethane preparation process to obtain an organosilicon-modified polyurethane emulsion. Using the organosilicon-modified polyurethane emulsion prepared in this application as a base material to prepare a polyurethane coating agent, and coating the polyurethane coating agent prepared in this application on the surface of the base fabric to form a complete hydrophobic film on the surface of the base fabric, so that the fabric has a high moisture permeability while maintaining a high hydrostatic pressure; while endowing the base fabric with high moisture permeability and water permeability, it has high water repellency performance.

[0026] In this application, carboxymethyl cellulose is crosslinked with epichlorohydrin, γ-aminopropyltriethoxysilane, and tetraethyl orthosilicate to form an organic-inorganic hybrid network structure with an interpenetrating network structure, which improves the moisture absorption rate of the material. Its end groups have a large number of hydroxyl groups, further promoting the improvement of the moisture absorption rate. Moreover, adding silica sol to modify carboxymethyl cellulose in this application effectively slows down the cracking of the film layer and improves the durability of the coating.

[0027] (2) The silica sol crosslinked carboxymethyl cellulose prepared in this application is crosslinked with polyurethane to obtain an organosilicon modified polyurethane emulsion; the ether bonds of the organosilicon modified polyurethane emulsion are easy to combine with water molecules to form weak hydrogen bonds, which have a good effect of absorbing and transferring moisture, and the moisture permeability is increased. In this application, the silica sol modified carboxymethyl cellulose is chemically crosslinked with organosilicon polyurethane. By using the moisture absorption ability of the modified carboxymethyl cellulose and the void effect between the composite interfaces of the carboxymethyl cellulose and the polyurethane molecular chains, a microporous coated fabric with good waterproof, moisture-permeable and breathable properties is prepared, effectively achieving the effect of rapid moisture conduction and drying, and realizing the moisture absorption and rapid drying performance of the fabric. Detailed implementation mode

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1 The preparation method of silica sol crosslinked carboxymethyl cellulose includes the following steps:

[0030] S1: Add 10 g of carboxymethyl cellulose and 50 mL of deionized water into a reaction kettle and disperse evenly. Add 2 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution, control the temperature at 50 °C, keep the reaction for 12 h, wash with ethanol, filter by suction, and dry to obtain Component 1;

[0031] S2: Add 10 g of Component 1 and 50 mL of deionized water into a reaction kettle and disperse evenly. Add 0.2 g of γ-aminopropyltriethoxysilane, control the temperature at 50 °C, keep the reaction for 12 h, centrifuge, wash, and dry to obtain Component 2;

[0032] S3: Add 10 g of Component 2, 5 g of tetraethyl orthosilicate, and 15 mL of absolute ethanol into a reaction kettle and disperse evenly. Add 10 mL of deionized water, add hydrochloric acid to adjust the pH to 4, control the temperature at 40 °C, keep the reaction for 1 h to obtain silica sol crosslinked carboxymethyl cellulose.

[0033] Example 2 The preparation method of silica sol crosslinked carboxymethyl cellulose includes the following steps:

[0034] S1: Add 10 g of carboxymethyl cellulose and 70 mL of deionized water into a reaction kettle and disperse evenly. Then add 4 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution. Control the temperature at 55 °C and keep the reaction for 16 h. Wash with ethanol, filter by suction, and dry to obtain Component 1.

[0035] S2: Add 10 g of Component 1 and 100 mL of deionized water into a reaction kettle and disperse evenly. Then add 0.3 g of γ-aminopropyltriethoxysilane. Control the temperature at 55 °C and keep the reaction for 15 h. Centrifuge, wash, and dry to obtain Component 2.

[0036] S3: Add 10 g of Component 2, 6 g of tetraethyl orthosilicate, and 20 mL of absolute ethanol into a reaction kettle and disperse evenly. Then add 15 mL of deionized water, add hydrochloric acid to adjust the pH to 4, control the temperature at 40 °C, and keep the reaction for 1 h to crosslink the silica sol with carboxymethyl cellulose.

[0037] Example 3 The preparation method of silica sol crosslinked carboxymethyl cellulose comprises the following steps:

[0038] S1: Add 10 g of carboxymethyl cellulose and 100 mL of deionized water into a reaction kettle and disperse evenly. Then add 4 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution. Control the temperature at 60 °C and keep the reaction for 24 h. Wash with ethanol, filter by suction, and dry to obtain Component 1.

[0039] S2: Add 10 g of Component 1 and 100 mL of deionized water into a reaction kettle and disperse evenly. Then add 0.4 g of γ-aminopropyltriethoxysilane. Control the temperature at 60 °C and keep the reaction for 24 h. Centrifuge, wash, and dry to obtain Component 2.

[0040] S3: Add 10 g of Component 2, 10 g of tetraethyl orthosilicate, and 25 mL of absolute ethanol into a reaction kettle and disperse evenly. Then add 20 mL of deionized water, add hydrochloric acid to adjust the pH to 5, control the temperature at 45 °C, and keep the reaction for 2 h to crosslink the silica sol with carboxymethyl cellulose.

[0041] Example 4 The preparation method of organosilicon modified polyurethane emulsion comprises the following steps:

[0042] In a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, add 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate. Control the temperature at 60 °C and keep the reaction for 2 h. Add 3 g of dimethylolpropionic acid and continue to keep the reaction for 2 h. Cool to room temperature, add 0.8 g of triethylamine and disperse evenly. Then raise the temperature to 65 °C, add 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 1, and keep the temperature for 0.5 h under stirring conditions. Rotate and evaporate to remove acetone to obtain an organosilicon-modified polyurethane emulsion.

[0043] Example 5 The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps:

[0044] In a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, add 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate. Control the temperature at 60 °C and keep the reaction for 2 h. Add 3 g of dimethylolpropionic acid and continue to keep the reaction for 2 h. Cool to room temperature, add 0.8 g of triethylamine and disperse evenly. Then raise the temperature to 65 °C, add 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 2, and keep the temperature for 0.5 h under stirring conditions. Rotate and evaporate to remove acetone to obtain an organosilicon-modified polyurethane emulsion.

[0045] Example 6 The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps:

[0046] In a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, add 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate. Control the temperature at 60 °C and keep the reaction for 2 h. Add 3 g of dimethylolpropionic acid and continue to keep the reaction for 2 h. Cool to room temperature, add 0.8 g of triethylamine and disperse evenly. Then raise the temperature to 65 °C, add 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 3, and keep the temperature for 0.5 h under stirring conditions. Rotate and evaporate to remove acetone to obtain an organosilicon-modified polyurethane emulsion.

[0047] Example 7 A preparation method of a microporous breathable fabric comprises the following steps:

[0048] A1: Clean the dispersion tank. First, add 100 g of the organosilicon-modified waterborne polyurethane acrylate emulsion prepared in Example 4 and 8 parts of N,N-dimethylacetamide into the tank and disperse evenly to form a premix;

[0049] A2: While stirring, add 2 parts of n-octanol and 5 parts of foam stabilizer (L-580) to the premix and disperse evenly;

[0050] A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent;

[0051] A4: Coat the polyurethane coating agent on the surface of nylon spun base fabric with a coating amount of 10 g / m 2 , oven temperature 90 °C, pre-dry for 3 min, oven temperature 150 °C, cure for 3 min to obtain a microporous breathable fabric.

[0052] Example 8 A method for preparing a microporous breathable fabric, comprising the following steps:

[0053] A1: Clean the dispersion tank, first add 100 g of the organosilicon-modified aqueous polyurethane acrylate emulsion prepared in Example 5 and 8 parts of N,N-dimethylacetamide into the tank and disperse evenly to form a pre-mixture;

[0054] A2: While stirring, add 2 parts of n-octanol and 5 parts of foam stabilizer (L-580) to the pre-mixture and disperse evenly;

[0055] A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent;

[0056] A4: Coat the polyurethane coating agent on the surface of nylon spun base fabric with a coating amount of 10 g / m 2 , oven temperature 90 °C, pre-dry for 3 min, oven temperature 150 °C, cure for 3 min to obtain a microporous breathable fabric.

[0057] Example 9 A method for preparing a microporous breathable fabric, comprising the following steps:

[0058] A1: Clean the dispersion tank, first add 100 g of the organosilicon-modified aqueous polyurethane acrylate emulsion prepared in Example 6 and 8 parts of N,N-dimethylacetamide into the tank and disperse evenly to form a pre-mixture;

[0059] A2: While stirring, add 2 parts of n-octanol and 5 parts of foam stabilizer (L-580) to the pre-mixture and disperse evenly;

[0060] A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent;

[0061] A4: Coat the polyurethane coating agent on the surface of nylon spun base fabric with a coating amount of 10 g / m 2 , oven temperature 90 °C, pre-dry for 3 min, oven temperature 150 °C, cure for 3 min to obtain a microporous breathable fabric.

[0062] Comparative Example 1 The preparation method of silica sol crosslinked carboxymethyl cellulose comprises the following steps:

[0063] S1: Add 10 g of carboxymethyl cellulose and 70 mL of deionized water into a reaction kettle and disperse evenly. Then add 4 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution, control the temperature at 55 °C, keep the temperature for reaction for 16 h, wash with ethanol, filter by suction, and dry to obtain Component 1.

[0064] S2: Add 10 g of Component 1 and 100 mL of deionized water into a reaction kettle and disperse evenly. Then add 0.3 g of γ-aminopropyltriethoxysilane, control the temperature at 55 °C, keep the temperature for reaction for 15 h, centrifuge, wash, and dry to obtain silica sol cross-linked carboxymethyl cellulose.

[0065] Comparative Example 2 The preparation method of silica sol cross-linked carboxymethyl cellulose includes the following steps:

[0066] S1: Add 10 g of carboxymethyl cellulose and 70 mL of deionized water into a reaction kettle and disperse evenly. Then add 4 mL of γ-glycidoxypropyltrimethoxysilane and 0.5 mL of 3 mol / L hydrochloric acid solution, control the temperature at 55 °C, keep the temperature for reaction for 16 h, wash with ethanol, filter by suction, and dry to obtain Component 1.

[0067] S2: Add 10 g of Component 1, 6 g of tetraethyl orthosilicate, and 20 mL of absolute ethanol into a reaction kettle and disperse evenly. Then add 15 mL of deionized water, add hydrochloric acid to adjust the pH to 4, control the temperature at 40 °C, keep the temperature for reaction for 1 h to obtain silica sol cross-linked carboxymethyl cellulose.

[0068] Comparative Example 3 The preparation method of modified carboxymethyl cellulose includes the following steps:

[0069] S1: Add 10 g of carboxymethyl cellulose and 70 mL of deionized water into a reaction kettle and disperse evenly. Then add 4 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution, control the temperature at 55 °C, keep the temperature for reaction for 16 h, wash with ethanol, filter by suction, and dry to obtain modified carboxymethyl cellulose.

[0070] Comparative Example 4 The preparation method of organosilicon-modified polyurethane emulsion includes the following steps:

[0071] Add 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate into a reaction flask equipped with a magnetic stirrer, thermometer, reflux condenser, and nitrogen protection device. Control the temperature at 60 °C, keep the temperature for reaction for 2 h, add 3 g of dimethylolpropionic acid, continue to keep the temperature for reaction for 2 h, cool to room temperature, add 0.8 g of triethylamine and disperse evenly, then raise the temperature to 65 °C, add 4 g of silica sol cross-linked carboxymethyl cellulose prepared in Comparative Example 1, keep the temperature for 0.5 h under stirring conditions, and remove acetone by rotary evaporation to obtain organosilicon-modified polyurethane emulsion.

[0072] Comparative Example 5 The preparation method of the silicone-modified polyurethane emulsion comprises the following steps:

[0073] In a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate were added. The temperature was controlled at 60 °C and the reaction was carried out under insulation for 2 h. Then 3 g of dimethylolpropionic acid was added and the reaction was continued under insulation for 2 h. After cooling to room temperature, 0.8 g of triethylamine was added and dispersed evenly. Then the temperature was raised to 65 °C, 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Comparative Example 2 was added, and the mixture was kept warm for 0.5 h under stirring conditions. Acetone was removed by rotary evaporation to obtain the silicone-modified polyurethane emulsion.

[0074] Comparative Example 6 The preparation method of the silicone-modified polyurethane emulsion comprises the following steps:

[0075] In a reaction flask equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, 10 g of polyether diol (average molecular weight 1000), 60 mL of acetone, 0.2 g of dibutyltin dilaurate, and 6 g of diphenylmethane diisocyanate were added. The temperature was controlled at 60 °C and the reaction was carried out under insulation for 2 h. Then 3 g of dimethylolpropionic acid was added and the reaction was continued under insulation for 2 h. After cooling to room temperature, 0.8 g of triethylamine was added and dispersed evenly. Then the temperature was raised to 65 °C, 4 g of the modified carboxymethyl cellulose prepared in Comparative Example 3 was added, and the mixture was kept warm for 0.5 h under stirring conditions. Acetone was removed by rotary evaporation to obtain the silicone-modified polyurethane emulsion.

[0076] Comparative Example 7 Compared with Example 8, only the silicone-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced with the silicone-modified polyurethane emulsion prepared in Comparative Example 4 in equal amount, and the other components and the preparation method were exactly the same as those in Example 8.

[0077] Comparative Example 8 Compared with Example 8, only the silicone-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced with the silicone-modified polyurethane emulsion prepared in Comparative Example 5 in equal amount, and the other components and the preparation method were exactly the same as those in Example 8.

[0078] Comparative Example 9 Compared with Example 8, only the silicone-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced with the silicone-modified polyurethane emulsion prepared in Comparative Example 6 in equal amount, and the other components and the preparation method were exactly the same as those in Example 8.

[0079] Performance Testing

[0080] (1)Waterproof performance: Detection was carried out according to GB / T4745-2012 "Determination of resistance to wetting of textile fabrics - Spray test", and washing treatment was carried out according to GB / T3921.1-2008 "Textiles - Tests for colour fastness - Colour fastness to washing". The water repellency grade of the specimen was distinguished according to the water repellency grade standard in Table 1, and the test results are shown in Table 2;

[0081] Table 1: Water repellency grade standard

[0082]

[0083] (2)Hydrostatic pressure resistance test: Detection was carried out according to GB / T4744-2013 "Determination of water penetration resistance of textile fabrics - Hydrostatic pressure test", and washing treatment was carried out according to GB / T3921.1-2008 "Textiles - Tests for colour fastness - Colour fastness to washing". The test results are shown in Table 2;

[0084] (3)Moisture vapor transmission rate: Determination was carried out according to the moisture permeation cup method: Method A in GB / T12704-1991 "Test method for moisture vapor transmission rate of fabrics", and the moisture vapor transmission rate Q was calculated according to the following formula:

[0085] Q = (ΔW × 24) / (A × t)

[0086] In the formula, Q - moisture vapor transmission rate, g / m 2 ˙24h; ΔW - moisture vapor transmission difference, g; A - moisture permeation area, m 2 ; t - moisture permeation time, h; The test results are shown in Table 3;

[0087] (4)Air permeability: Detection was carried out according to ASTM D773 using a Frazier air permeability tester, and 129 - 249 Pa was selected for detection. The test results are shown in Table 3;

[0088] Table 2: Statistical table of waterproof performance test data for Examples 7 - 9 and Comparative Examples 7 - 9

[0089]

[0090] As can be seen from Table 2, after the base fabric is treated with the polyurethane coating agent prepared in this application, it endows the base fabric with excellent water repellency performance and still maintains good water repellency performance even after multiple washes.

[0091] Table 3: Statistical table of air permeability and moisture vapor transmission performance test data for Examples 7 - 9 and Comparative Examples 7 - 9

[0092]

[0093] As can be seen from Table 3, after the base fabric is treated with the polyurethane coating agent prepared in this application, it has the characteristics of high moisture vapor transmission and air permeability.

[0094] The above has described in detail an embodiment of the present invention, but the above content is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made in accordance with the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for preparing a microporous breathable fabric, characterized in that: The method comprises the following steps: applying a polyurethane coating agent on the surface of a base fabric and then drying the coating agent to obtain a microporous breathable fabric; The polyurethane coating agent comprises the following raw materials in parts by weight: 100 parts of organosilicon-modified polyurethane emulsion, 8-11 parts of N,N-dimethylacetamide, 2-2.5 parts of n-octanol, 5-8 parts of foaming agent, and 1-3 parts of thickener PTF; The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps: Add polyether diol, acetone, dibutyltin dilaurate and diphenylmethane diisocyanate to a reaction bottle equipped with a magnetic stirrer, a thermometer, a reflux condenser and a nitrogen protection device, control the temperature to 55-65°C, keep the temperature for reaction for 1-3h, add dimethylolpropionic acid, continue to keep the temperature for reaction for 1-3h, cool to room temperature, add triethylamine to disperse evenly, then heat to 55-65°C, add silica sol cross-linked carboxymethyl cellulose, keep the temperature for 0.5-1h under stirring, remove acetone by rotary evaporation, and obtain a silicone-modified polyurethane emulsion; The preparation method of the silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: Add carboxymethyl cellulose and deionized water into a reaction kettle and disperse them evenly, add epichlorohydrin and hydrochloric acid solution, control the temperature at 50-60°C, keep the temperature for reaction for 12-24h, wash with ethanol, filter and dry to obtain component 1; S2: Add component 1 and deionized water into a reaction kettle and disperse them evenly, add γ-aminopropyltriethoxysilane, control the temperature at 50-60°C, keep the reaction warm for 12-24 hours, centrifuge, wash and dry to obtain component 2; S3: Add component 2, tetraethyl orthosilicate and anhydrous ethanol into the reaction kettle and disperse them evenly, add deionized water, add hydrochloric acid to adjust the pH to 4-5, control the temperature at 40-45°C, keep the reaction warm for 1-2 hours, and cross-link the carboxymethyl cellulose with silica sol.

2. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The addition ratio of polyether diol, acetone, dibutyltin dilaurate, diphenylmethane diisocyanate, dihydroxymethylpropionic acid, triethylamine, and silica sol cross-linked carboxymethyl cellulose is 10g: 50-100mL: 0.2-0.4g: 5-10g: 2-4g: 0.6-1g: 2-4g.

3. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The addition ratio of the hydrochloric acid solution in S1 is 3-6 mol / L hydrochloric acid aqueous solution; the addition ratio of carboxymethyl cellulose, deionized water, epichlorohydrin, and hydrochloric acid solution is 10 g: 50-100 mL: 2-4 mL: 0.5-1 mL.

4. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The addition ratio of component 1, deionized water, and γ-aminopropyltriethoxysilane in S2 is 10 g: 50-100 mL: 0.2-0.4 g.

5. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The addition ratio of component 2, tetraethyl orthosilicate, anhydrous ethanol, and deionized water in S3 is 10 g: 5-10 g: 15-25 mL: 10-20 mL.

6. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The base fabric is any one of a cotton-spun base fabric, a polyester-spun base fabric, a nylon-spun base fabric, a cotton-polyester blended base fabric, and a cotton-nylon blended base fabric.

7. The method for preparing a microporous breathable fabric according to claim 1, characterized in that: The coating amount of polyurethane coating agent is 5-25g / m 2 .

8. A microporous breathable fabric, characterized in that: Prepared by the preparation method described in any one of claims 1 to 7.

9. A microporous breathable fabric as claimed in claim 8, applied to the field of outdoor sportswear.

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