Microporous breathable fabric, preparation method and application

Abstract

The invention discloses a microporous breathable fabric as well as a preparation method and application thereof, and relates to the technical field of fabric treatment. The invention discloses a preparation method of a microporous breathable fabric, which comprises the following steps: coating the surface of a base cloth with a polyurethane coating agent, and drying to obtain the microporous breathable fabric, the polyurethane coating agent is prepared from the following raw materials in parts by weight: 100 parts of organic silicon modified polyurethane emulsion, 8 to 11 parts of N, N-dimethylacetamide, 2 to 2.5 parts of n-caprylic alcohol, 5 to 8 parts of a foam homogenizing agent and 1 to 3 parts of a thickening agent PTF; the organic silicon modified polyurethane emulsion is obtained by crosslinking polyurethane with carboxymethyl cellulose through silica sol; the polyurethane coating agent prepared by taking the organic silicon modified polyurethane emulsion as the base material is coated on the surface of the base cloth, so that the fabric has high waterproof performance and also has high air permeability and moisture permeability; the microporous breathable fabric prepared by the invention is applied to the field of outdoor sportswear, and comfortable wearing experience is provided.

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

[0005] The purpose of the present invention can be achieved by the following technical solutions: A method for preparing a microporous breathable fabric comprises the following steps: coating a polyurethane coating agent on the surface of a base fabric and then drying the coating agent to obtain the 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 silicone-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 reaction warm for 1-3h, add dihydroxymethylpropionic acid, continue to keep the reaction warm for 1-3h, cool to room temperature, add triethylamine to disperse evenly, then raise the temperature to 55-65°C, add silica sol cross-linked carboxymethyl cellulose, keep the temperature warm for 0.5-1h under stirring, remove acetone by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0006] As a further embodiment of the present invention, the addition ratio of polyether diol, acetone, dibutyltin dilaurate, diphenylmethane diisocyanate, dihydroxymethylpropionic acid, triethylamine, and silica sol cross-linked 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.

[0007] As a further embodiment of the present invention: the preparation method of 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.

[0008] As a further solution of the present invention: 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.

[0009] As a further solution of the present invention: the addition ratio of component 1, deionized water and γ-aminopropyltriethoxysilane in S2 is 10 g: 50-100 mL: 0.2-0.4 g.

[0010] As a further solution of the present invention: the addition ratio of component 2, tetraethyl orthosilicate, anhydrous ethanol and deionized water in S3 is 10g: 5-10g: 15-25mL: 10-20mL.

[0011] As a further solution of the present invention: 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.

[0012] As a further embodiment of the present invention: the coating amount of the polyurethane coating agent is 5-25g / m 2 .

[0013] As a further solution of the present invention: the specific steps of drying are: oven temperature 90-100°C, pre-baking for 3 minutes, oven temperature 150-160°C, baking for 2-3 minutes.

[0014] A microporous breathable fabric is made by any of the above preparation methods.

[0015] The above-mentioned microporous breathable fabric is applied in the field of outdoor sportswear.

[0016] Beneficial effects of the present invention: (1) This application uses carboxymethyl cellulose as a raw material, and obtains component one by esterification reaction between epichlorohydrin and the carboxyl group of carboxymethyl cellulose; and uses component one to react with γ-aminopropyltriethoxysilane to undergo nucleophilic substitution reaction to obtain component two; and then uses component two to co-hydrolyze with tetraethyl orthosilicate to obtain silica sol cross-linked carboxymethyl cellulose; finally, the silica sol cross-linked carboxymethyl cellulose is added to the polyurethane preparation process to obtain an organosilicon-modified polyurethane emulsion. The organosilicon-modified polyurethane emulsion prepared in this application is used as a base material to prepare a polyurethane coating agent, and the polyurethane coating agent prepared in this application is coated on the surface of a 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 water pressure resistance; while giving the base fabric high moisture permeability and water permeability, it also has high water repellency.

[0017] The carboxymethyl cellulose of the present application is cross-linked with epichlorohydrin, γ-aminopropyltriethoxysilane and tetraethyl orthosilicate to generate an organic-inorganic hybrid network structure with an interpenetrating network structure, which improves the moisture absorption rate of the material, and its end groups have a large number of hydroxyl groups, which further promotes the improvement of the moisture absorption rate. Moreover, the addition of silica sol to modify the carboxymethyl cellulose of the present application effectively slows down the cracking of the film layer and improves the durability of the coating.

[0018] (2) The silica sol cross-linked carboxymethyl cellulose prepared in the present application is cross-linked with polyurethane to obtain a silicone modified polyurethane emulsion; the ether bonds of the silicone modified polyurethane emulsion are easy to combine with water molecules to form weak hydrogen bonds, and have a good moisture absorption and moisture transfer effect, thereby increasing the moisture permeability. The present application utilizes silica sol modified carboxymethyl cellulose and silicone polyurethane for chemical cross-linking, and utilizes the moisture absorption capacity of the modified carboxymethyl cellulose and the gap between the composite interface between the carboxymethyl fiber and the polyurethane molecular chain to prepare a microporous coated fabric with good waterproof, moisture permeability and air permeability, effectively achieving the effect of moisture conduction and quick drying, and achieving the moisture absorption and quick drying performance of the fabric. DETAILED DESCRIPTION

[0019] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1 The preparation method of silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: 10 g carboxymethyl cellulose and 50 mL deionized water were added to a reaction kettle and dispersed evenly, 2 mL epichlorohydrin and 0.5 mL 3 mol / L hydrochloric acid solution were added, the temperature was controlled at 50°C, the reaction was kept warm for 12 h, washed with ethanol, filtered and dried to obtain component 1; S2: 10 g of component 1 and 50 mL of deionized water were added to a reaction kettle and dispersed evenly, 0.2 g of γ-aminopropyltriethoxysilane was added, the temperature was controlled at 50°C, the reaction was kept warm for 12 h, centrifuged, washed, and dried to obtain component 2; S3: Add 10g of component 2, 5g of tetraethyl orthosilicate, and 15mL of anhydrous ethanol into the reaction kettle and disperse them evenly. Add 10mL of deionized water and hydrochloric acid to adjust the pH to 4. Control the temperature at 40°C and keep the reaction warm for 1h. The silica sol cross-links the carboxymethyl cellulose.

[0021] Example 2 The preparation method of silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: 10 g carboxymethyl cellulose and 70 mL deionized water were added to a reactor and dispersed evenly, 4 mL epichlorohydrin and 0.5 mL 3 mol / L hydrochloric acid solution were added, the temperature was controlled at 55°C, the reaction was kept warm for 16 h, washed with ethanol, filtered and dried to obtain component 1; S2: 10 g of component 1 and 100 mL of deionized water were added to a reaction kettle and dispersed evenly, 0.3 g of γ-aminopropyltriethoxysilane was added, the temperature was controlled at 55°C, the reaction was kept warm for 15 h, centrifuged, washed, and dried to obtain component 2; S3: Add 10g of component 2, 6g of tetraethyl orthosilicate, and 20mL of anhydrous ethanol into the reactor and disperse evenly, add 15mL of deionized water, add hydrochloric acid to adjust the pH to 4, control the temperature at 40°C, keep the reaction warm for 1h, and cross-link the carboxymethyl cellulose with silica sol.

[0022] Example 3 The preparation method of silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: 10 g of carboxymethyl cellulose and 100 mL of deionized water were added to a reactor and dispersed evenly, 4 mL of epichlorohydrin and 0.5 mL of 3 mol / L hydrochloric acid solution were added, the temperature was controlled at 60°C, the reaction was kept warm for 24 h, washed with ethanol, filtered and dried to obtain component 1; S2: 10 g of component 1 and 100 mL of deionized water were added to a reaction kettle and dispersed evenly, 0.4 g of γ-aminopropyltriethoxysilane was added, the temperature was controlled at 60°C, the reaction was kept warm for 24 hours, centrifuged, washed, and dried to obtain component 2; S3: Add 10g of component 2, 10g of tetraethyl orthosilicate, and 25mL of anhydrous ethanol into the reactor and disperse evenly, add 20mL of deionized water, add hydrochloric acid to adjust the pH to 5, control the temperature at 45°C, keep the reaction warm for 2h, and cross-link the carboxymethyl cellulose with silica sol.

[0023] Example 4 The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps: 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., the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65° C., 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 1 was added, the temperature was kept warm for 0.5 h under stirring, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0024] Example 5 The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps: 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., the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65° C., 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 2 was added, the temperature was kept warm for 0.5 h under stirring conditions, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0025] Example 6 The preparation method of the organosilicon-modified polyurethane emulsion comprises the following steps: 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., the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65° C., 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Example 3 was added, the temperature was kept warm for 0.5 h under stirring conditions, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0026] Embodiment 7 A method for preparing a microporous breathable fabric comprises the following steps: A1: Clean the dispersion tank, 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 them evenly to form a premix; A2: Add 2 parts of n-octanol and 5 parts of equalizing agent (L-580) to the premix while stirring and disperse evenly; A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent; A4: Apply polyurethane coating agent on the surface of nylon spun base fabric, with a coating amount of 10g / m 2 , oven temperature 90°C, pre-bake for 3 minutes, oven temperature 150°C, bake for 3 minutes to obtain a microporous breathable fabric.

[0027] Embodiment 8 A method for preparing a microporous breathable fabric comprises the following steps: A1: Clean the dispersion tank, add 100 g of the organosilicon-modified waterborne polyurethane acrylate emulsion prepared in Example 5 and 8 parts of N,N-dimethylacetamide into the tank and disperse them evenly to form a premix; A2: Add 2 parts of n-octanol and 5 parts of equalizing agent (L-580) to the premix while stirring and disperse evenly; A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent; A4: Apply polyurethane coating agent on the surface of nylon spun base fabric, with a coating amount of 10g / m 2 , oven temperature 90°C, pre-bake for 3 minutes, oven temperature 150°C, bake for 3 minutes to obtain a microporous breathable fabric.

[0028] Embodiment 9 A method for preparing a microporous breathable fabric comprises the following steps: A1: Clean the dispersion tank, add 100 g of the silicone-modified waterborne polyurethane acrylate emulsion prepared in Example 6 and 8 parts of N,N-dimethylacetamide into the tank and disperse them evenly to form a premix; A2: Add 2 parts of n-octanol and 5 parts of equalizing agent (L-580) to the premix while stirring and disperse evenly; A3: Add thickener PTF and disperse evenly to obtain a polyurethane coating agent; A4: Apply polyurethane coating agent on the surface of nylon spun base fabric, with a coating amount of 10g / m 2 , oven temperature 90°C, pre-bake for 3 minutes, oven temperature 150°C, bake for 3 minutes to obtain a microporous breathable fabric.

[0029] Comparative Example 1 The preparation method of silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: 10 g carboxymethyl cellulose and 70 mL deionized water were added to a reactor and dispersed evenly, 4 mL epichlorohydrin and 0.5 mL 3 mol / L hydrochloric acid solution were added, the temperature was controlled at 55°C, the reaction was kept warm for 16 h, washed with ethanol, filtered and dried to obtain component 1; S2: Add 10 g of component 1 and 100 mL of deionized water into a reactor and disperse them evenly, add 0.3 g of γ-aminopropyltriethoxysilane, control the temperature to 55°C, keep the reaction warm for 15 hours, centrifuge, wash, and dry to obtain silica sol cross-linked carboxymethyl cellulose.

[0030] Comparative Example 2 The preparation method of silica sol cross-linked carboxymethyl cellulose comprises the following steps: S1: 10 g of carboxymethyl cellulose and 70 mL of deionized water were added to a reaction kettle and dispersed evenly, 4 mL of γ-glycidyloxypropyltrimethoxysilane and 0.5 mL of 3 mol / L hydrochloric acid solution were added, the temperature was controlled at 55°C, the reaction was kept warm for 16 h, washed with ethanol, filtered and dried to obtain component 1; S2: Add 10g of component 1, 6g of tetraethyl orthosilicate, and 20mL of anhydrous ethanol into a reactor and disperse them evenly. Add 15mL of deionized water and hydrochloric acid to adjust the pH to 4. Control the temperature at 40°C and keep the reaction warm for 1h. The silica sol cross-links the carboxymethyl cellulose.

[0031] Comparative Example 3 The preparation method of modified carboxymethyl cellulose comprises the following steps: S1: Add 10g carboxymethyl cellulose and 70mL deionized water into a reactor and disperse them evenly. Add 4mL epichlorohydrin and 0.5mL 3mol / L hydrochloric acid solution. Control the temperature at 55°C and keep the reaction for 16h. Wash with ethanol, filter and dry to obtain modified carboxymethyl cellulose.

[0032] Comparative Example 4 The preparation method of the silicone-modified polyurethane emulsion comprises the following steps: In a reaction bottle 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, the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65°C, 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Comparative Example 1 was added, the temperature was kept warm for 0.5 h under stirring, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0033] Comparative Example 5 The preparation method of the silicone-modified polyurethane emulsion comprises the following steps: In a reaction bottle 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, the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65°C, 4 g of the silica sol cross-linked carboxymethyl cellulose prepared in Comparative Example 2 was added, the temperature was kept warm for 0.5 h under stirring, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0034] Comparative Example 6 The preparation method of the silicone-modified polyurethane emulsion comprises the following steps: In a reaction bottle 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, the reaction was kept warm for 2 h, 3 g of dihydroxymethylpropionic acid was added, the reaction was continued for 2 h, the temperature was cooled to room temperature, 0.8 g of triethylamine was added and dispersed evenly, the temperature was then raised to 65°C, 4 g of modified carboxymethyl cellulose prepared in Comparative Example 3 was added, the temperature was kept warm for 0.5 h under stirring, and the acetone was removed by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

[0035] Comparative Example 7 Compared with Example 8, only the organosilicon-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced by the organosilicon-modified polyurethane emulsion prepared in Comparative Example 4 in equal amount, and the other components and preparation method were completely the same as those in Example 8.

[0036] Comparative Example 8 Compared with Example 8, only the organosilicon-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced by the organosilicon-modified polyurethane emulsion prepared in Comparative Example 5 in equal amount, and the other components and preparation method were completely the same as those in Example 8.

[0037] Comparative Example 9 Compared with Example 8, only the organosilicon-modified polyurethane emulsion prepared in Example 5 used in Example 8 was replaced by the organosilicon-modified polyurethane emulsion prepared in Comparative Example 6 in equal amount, and the other components and preparation method were completely the same as those in Example 8.

[0038] Performance Testing (1) Waterproof performance: Tested in accordance with GB / T4745-2012 "Test for Determination of Surface Wetness Resistance of Textile Fabrics - Water Touch Test" and washed in accordance with GB / T3921.1-2008 "Textiles - Tests for Colour Fastness - Colour Fastness to Washing". The water repellency level of the test samples was distinguished according to the water repellency level standard in Table 1. The test results are shown in Table 2. Table 1: Water repellency rating standards

[0039] (2) Water pressure resistance test: Tested in accordance with GB / T4744-2013 "Hydrostatic pressure test for determination of water permeability resistance of textile fabrics" and washed in accordance with GB / T3921.1-2008 "Textiles - Tests for colour fastness - Colour fastness to washing". The test results are shown in Table 2. (3) Moisture permeability: Determine according to the moisture permeability cup method: Method A of GB / T12704-1991 "Test method for moisture permeability of fabrics", and calculate the moisture permeability Q according to the following formula: Q = (ΔW × 24) / (A × t) In the formula, Q-moisture vapor transmission rate, g / m 2 ˙24h; ΔW-moisture permeability difference, g; A-moisture permeability area, m 2 ; t-wet permeability time, h; the test results are shown in Table 3; (4) Air permeability: According to ASTM D773, the Frazier air permeability tester was used to test the air permeability at 129-249 Pa. The test results are shown in Table 3. Table 2: Statistical table of waterproof performance test data of Examples 7-9 and Comparative Examples 7-9

[0040] As can be seen from Table 2, after the polyurethane coating agent prepared in the present application is treated with the base fabric, the base fabric is endowed with excellent water-repellent properties, and the base fabric still maintains good water-repellent properties even after multiple washings.

[0041] Table 3: Statistical table of air and moisture permeability test data of Examples 7-9 and Comparative Examples 7-9

[0042] It can be seen from Table 3 that after the base fabric is treated with the polyurethane coating agent prepared in the present application, it has the characteristics of high moisture permeability and air permeability.

[0043] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage 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 reaction warm for 1-3h, add dihydroxymethylpropionic acid, continue to keep the reaction warm for 1-3h, cool to room temperature, add triethylamine to disperse evenly, then raise the temperature to 55-65°C, add silica sol cross-linked carboxymethyl cellulose, keep the temperature warm for 0.5-1h under stirring, remove acetone by rotary evaporation to obtain a silicone-modified polyurethane emulsion.

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 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.

4. The method for preparing a microporous breathable fabric according to claim 3, 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.

5. The method for preparing a microporous breathable fabric according to claim 3, 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.

6. The method for preparing a microporous breathable fabric according to claim 3, 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.

7. 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.

8. 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 .

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

10. The microporous breathable fabric as claimed in claim 9 is used in the field of outdoor sportswear.

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