Waterproof breathable composite fabric and preparation process thereof

Abstract

The invention relates to the technical field of research and development of waterproof and breathable films, and discloses a waterproof and breathable composite fabric and a preparation process thereof.The product structure of the fabric is as follows: polyester high-elastic twill fabric is used as a fabric, hot melt mesh glue is used as a middle layer, and a polyurethane waterproof and breathable film is used as a lining. The fabric, the middle layer and the lining are laminated and compounded on a pressing machine, and the waterproof and breathable composite fabric is prepared; the polyurethane waterproof moisture-permeable film comprises an isocyanate prepolymerization component and a polyol component, a hydroxyl-terminated alkyl long-chain linear or cage-containing siloxane monomer is chemically introduced into an isocyanate prepolymerization component, and a solvent-free double-component reaction coating curing process is adopted to prepare the polyurethane film with excellent waterproof performance. The water resistance of the prepared polyurethane film product can meet the commercial use requirement.

Description

Technical Field

[0001] This invention relates to the field of waterproof and breathable membrane research and development technology, and in particular to a waterproof and breathable composite fabric and its preparation process. Background Technology

[0002] Waterproof and breathable fabrics made from waterproof and breathable materials can prevent water molecules from penetrating the fabric under certain pressure, while allowing sweat to be conducted to the outside as water vapor, maintaining the comfort and dryness of the fabric. They belong to a high-level functional fabric category. Based on processing methods, waterproof and breathable materials mainly include three types: high-density fabrics, coated fabrics, and laminated fabrics. Laminated fabrics, which combine the excellent properties of other fabrics, are gaining an increasing market share. Their preparation method generally involves bonding a waterproof and breathable functional membrane and a base fabric using hot melt adhesive or other adhesives under appropriate hot-pressing temperatures, pressures, and hot roller bonding speeds.

[0003] Waterproof and breathable membranes can be divided into fluorinated membranes and fluorine-free membranes. Due to the bioaccumulation and durability of fluorides, polyurethane dense membranes have received much attention in recent years as the mainstream fluorine-free waterproof and breathable membranes on the market. However, because polyurethane molecular chains usually contain hydrophilic groups (such as ether bonds, urethane groups, etc.), unmodified polyurethane nanofiber membranes, due to their inherent hydrophilicity, lack effective hydrophobic channels and are usually difficult to resist liquid water penetration.

[0004] This invention cites the following references: The master's thesis of Chen Chang, published by Guangxi University in 2023, entitled "Preparation of cage-type silsesquioxane (POSS) and its application in coatings", disclosed the chemical structure and synthesis method of cage-type silsesquioxane (POSS) T8-NH2. Summary of the Invention

[0005] This invention introduces hydrophobic alkyl long-chain and siloxane components into a polyurethane system, and prepares a polyurethane waterproof and breathable membrane through a reactive hot melt coating process. This membrane is then laminated with fabric to obtain a waterproof and breathable composite fabric, which has high market value in the field of waterproof and breathable materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A polyurethane waterproof and breathable membrane, wherein the membrane raw material comprises an isocyanate prepolymer component and a polyol component; The formulation of the isocyanate prepolymer component is as follows: 10 parts by weight of terminal hydroxyl alkyl long-chain siloxane monomer, 10 parts by weight of polyethylene glycol, 20-30 parts by weight of polypropylene glycol, and 50-60 parts by weight of 4,4-diphenylmethane diisocyanate. The hydroxyl-terminated alkyl long-chain siloxane monomer is one or a combination of hydroxyl-terminated alkyl long-chain linear siloxane monomer and hydroxyl-terminated alkyl long-chain cage-type siloxane monomer. The polyol component is formulated as follows: 70 parts by weight of polyethylene glycol, 30 parts by weight of polytetrahydrofuran glycol, 3-4 parts by weight of 1,4-butanediol, 0.1-1.5 parts by weight of leveling agent, and 0.05-0.5 parts by weight of wetting agent.

[0007] Preferably, the relative molecular weights of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran glycol are 2000 and 2000, respectively.

[0008] A process for preparing a polyurethane waterproof and breathable membrane includes the following steps: Step 1: Add hydroxyl-terminated alkyl long-chain siloxane monomers, polyethylene glycol, and polypropylene glycol to a reactor. Dehydrate the mixture by passing nitrogen gas through it at 85-95°C until the water content drops below 0.05%. Then add 4,4-diphenylmethane diisocyanate, heat to 70-80°C, and stir the reaction at 200-400 rpm. When the isocyanate content reaches 3.5%-4.0%, cool down and stop the reaction to obtain the isocyanate prepolymer component. Step 2: Prepare the ingredients according to the polyol component formula, and stir and mix them evenly at 800-900 rpm to obtain the polyol component; Step 3: Add the isocyanate prepolymer component and polyol component according to the isocyanate index of 1.03-1.08, as follows: First, stir the polyol component and catalyst at 800-900 rpm for 4-6 minutes, then add the isocyanate prepolymer component and stir evenly. Coat the mixture onto the release film with a coating thickness of 0.2-0.3 mm, and cure it at 100-120℃ for 1-5 minutes to obtain a polyurethane waterproof and breathable membrane.

[0009] Preferably, the catalyst used in step three is 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, and the amount of the catalyst is 0.7-1.0 parts by weight.

[0010] A waterproof and breathable composite fabric, wherein the product structure of the fabric is: polyester high-elastic twill fabric as the outer layer, hot melt adhesive as the middle layer, and polyurethane waterproof and breathable membrane as the inner layer.

[0011] Preferably, the hot melt adhesive is W120 type copolyamide Co-PA hot melt adhesive or A024 type thermoplastic polyurethane hot melt adhesive.

[0012] A process for preparing a waterproof and breathable composite fabric involves laminating the fabric, intermediate layer, and lining on a heat press to obtain the waterproof and breathable composite fabric. The lamination process parameters are: temperature 120-150℃, pressure 0.3-0.5kPa, and heat pressing time 10-40s.

[0013] Preferably, the waterproof and breathable composite fabric is used as a raw material for manufacturing waterproof and breathable clothing.

[0014] The beneficial effects of this invention are as follows: By integrating undecyl, benzene ring and linear or cage-like siloxane structures into a single molecular structure through molecular design, long-chain monomers containing linear or cage-like siloxanes with terminal hydroxyl alkyl groups are synthesized. By chemically introducing terminal hydroxyl alkyl long-chain linear or cage-like siloxane monomers into a polyurethane matrix and employing a solvent-free two-component reactive coating and curing process, a polyurethane film with excellent waterproof and breathable properties was prepared. Experimental results demonstrate that the water resistance of this film product meets the requirements for commercial use. Detailed Implementation

[0015] Experimental Example 1:

[0016] The synthetic mechanism for synthesizing long-chain linear siloxane monomers with terminal hydroxyl alkyl groups is as follows: One molar equivalent of tetramethyldivinyldisiloxane reacts with two molar equivalents of dimethylphenylsilane in a hydrosilylation reaction to yield a terminal phenylsiloxane monomer. One molar equivalent of a terminal phenyl siloxane monomer is subjected to a Friedel-Crafts alkylation reaction with two molar equivalents of undecenol to obtain a terminal hydroxyl alkylated long-chain linear siloxane monomer. The specific experimental steps for preparing hydroxyl-terminated alkylated long-chain linear siloxane monomers are as follows: 1.9 g of tetramethyldivinyldisiloxane was added to 20 mL of toluene and mixed thoroughly. Under nitrogen atmosphere and room temperature, 2.8 g of dimethylphenylsilane and 1 drop of isopropanol chloroplatinate solution were added and mixed thoroughly. The mixture was stirred and reacted for 3 h. Toluene was distilled off under reduced pressure, washed, and dried to obtain the terminal phenylsiloxane monomer. 4.6 g of terminal phenyl siloxane monomer and 3.4 g of undecenol were added to 50 mL of dichloromethane and stirred continuously. The reaction temperature was controlled at 25 °C. 0.3 g of anhydrous aluminum chloride was added. After reacting for 1 h, the dichloromethane was distilled off, washed, and dried to obtain a terminal hydroxyl alkyl long-chain linear siloxane monomer. The chemical structural formula of the hydroxyl-terminated alkyl long-chain linear siloxane monomer is as follows: ; The 1H NMR characterization results of the terminal hydroxyl alkylated long-chain linear siloxane monomers are as follows: 1 H NMR (400MHz, DMSO-D6, δ, ppm): 0.06 (s, 12H), 0.27 (s, 12H), 0.74-0.78 (t, 4H), 1.05-1.09 (t, 4H), 1.25-1. 35(m, 28H), 1.52-1.64(m, 8H), 2.61-2.66(m, 6H), 3.54-3.58(m, 4H), 6.96-6.98(d, 4H), 7.44-7.46(d, 4H).

[0017] Experimental Example 2:

[0018] The synthetic mechanism of hydroxyl-terminated alkyl long-chain cage-like siloxane monomers is as follows: One molar equivalent of caged silsesquioxane (POSS)T8-NH2 reacts with two molar equivalents of phenyl methacrylate in an aminoenyl addition reaction to give a phenyl-terminated caged siloxane monomer. One molar equivalent of a phenyl-terminated caged siloxane monomer is reacted with two molar equivalents of undecenol via Friedel-Crafts alkylation to yield a hydroxyl-terminated alkylated long-chain caged siloxane monomer. The specific experimental steps for preparing long-chain cage-like siloxane monomers with terminal hydroxyl alkylation are as follows: 5.8 g of cage-like silsesquioxane (POSS)T8-NH2 was added to 100 mL of dry dichloromethane. After stirring and mixing evenly, 3.3 g of phenyl methacrylate was added. The temperature was controlled not to exceed 30 °C, and the mixture was stirred under normal pressure for 8 h. After the reaction was completed, the dichloromethane was distilled off, washed, and dried to obtain a phenyl-terminated cage-like siloxane monomer. 9g of terminal phenyl cage-like siloxane monomer was added to 100mL of dichloroethane and stirred until homogeneous. Then, 3.4g of undecenol was added and stirred for 30min. Next, 0.4g of anhydrous aluminum chloride was added, and the temperature was raised to 55℃. The reaction was carried out for 6h. After the reaction was completed, the mixture was cooled to room temperature, the dichloroethane was distilled off, washed, and dried to obtain the terminal hydroxyl alkyl long-chain cage-like siloxane monomer. The chemical structural formula of the hydroxyl-terminated alkyl long-chain cage-like siloxane monomer is as follows: ; The 1H NMR characterization results of the terminal hydroxyl alkyl long-chain cage-like siloxane monomers are as follows: 1H NMR (400MHz, DMSO-D6, δ, ppm): 0.05-0.06 (d, 21H), 0.58-0.71 (m, 2H), 1.18-1.71 (m, 44H) , 2.48-2.74(m, 8H), 2.86-3.00(m, 4H), 3.45-3.58(m, 4H), 4.27-4.31(t, 2H), 7.02(s, 8H).

[0019] Example 1:

[0020] A polyurethane waterproof and breathable membrane is prepared, wherein the raw material formula of the polyurethane waterproof and breathable membrane is as follows:

[0021] Note: The catalyst used when mixing the isocyanate prepolymer component and the polyol component in Table 1 is 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, and the amount of this catalyst is 0.8 parts by weight. The preparation process of the polyurethane waterproof and breathable membrane includes the following steps: Step 1: Hydroxyl-terminated alkyl long-chain siloxane monomers, polyethylene glycol, and polypropylene glycol are added to a reactor. Nitrogen gas is introduced at 90°C to dehydrate the mixture until the water content drops below 0.05%. Then, 4,4-diphenylmethane diisocyanate is added, the temperature is raised to 80°C, and the mixture is stirred at 300 rpm. The isocyanate content is monitored until it reaches 3.5%-4.0%, at which point the temperature is lowered to stop the reaction, thus obtaining the isocyanate prepolymer component. Step 2: Prepare the ingredients according to the polyol component formula, and stir and mix them evenly at 850 rpm to obtain the polyol component; Step 3: Add the isocyanate prepolymer component and polyol component according to the isocyanate index of 1.05, as follows: First, stir the polyol component and catalyst at 850 rpm for 5 minutes, then add the isocyanate prepolymer component and stir evenly. Coat the mixture onto the release film with a coating thickness of 0.25 mm, and cure at 110℃ for 3 minutes to obtain a polyurethane waterproof and breathable membrane.

[0022] Hydrostatic pressure resistance of polyurethane waterproof and breathable membrane: The hydrostatic pressure resistance of the product was tested according to GB / T 4744-2013 "Test and Evaluation of Waterproof Performance of Textiles - Hydrostatic Pressure Method". The test area was 100 cm². 2 The boost rate is 600 mmH2O / min.

[0023] Note: In the comparative example, polyethylene glycol (Mn=2000) and polypropylene glycol (Mn=2000) were compounded in equal mass to replace the terminal hydroxyl alkyl long-chain siloxane monomers in the polyurethane waterproof and breathable membrane, thus obtaining an unmodified polyurethane waterproof and breathable membrane.

[0024] Example 2:

[0025] The preparation process of the waterproof and breathable composite fabric is as follows: Polyester high-elastic twill fabric (thickness 0.29mm, density 47×42 yarns / (10cm), yarn fineness 8.3tex, 2 / 2 twill) is used as the fabric, and hot melt adhesive (W120 type copolyamide Co-PA, melting point 115-130℃, weight 12g / m²) is used. 2 As the middle layer, a polyurethane waterproof and breathable membrane is used as the lining material. The membrane is laminated on a heat press machine at a temperature of 130℃ and a pressure of 0.3kPa for 20 seconds to obtain a waterproof and breathable composite fabric.

[0026] Note: The moisture permeability in Table 4 was tested using the inverted cup method. The test parameters were: a circular test cup with a diameter of 127 mm, a relative humidity of 50%, a temperature of 23 °C, distilled water added to the permeability cup, 20 mm away from the sample, a water height of 5 mm, and a grid 6 mm away from the sample.

Claims

1. A polyurethane waterproof and breathable membrane, characterized in that, The membrane raw material includes an isocyanate prepolymer component and a polyol component; The formulation of the isocyanate prepolymer component is as follows: 10 parts by weight of terminal hydroxyl alkyl long-chain siloxane monomer, 10 parts by weight of polyethylene glycol, 20-30 parts by weight of polypropylene glycol, and 50-60 parts by weight of 4,4-diphenylmethane diisocyanate. The hydroxyl-terminated alkyl long-chain siloxane monomer is one or a combination of hydroxyl-terminated alkyl long-chain linear siloxane monomer and hydroxyl-terminated alkyl long-chain cage-type siloxane monomer. The chemical structural formula of the hydroxyl-terminated alkyl long-chain linear siloxane monomer is as follows: ； The chemical structural formula of the hydroxyl-terminated alkyl long-chain cage-like siloxane monomer is as follows: ； The polyol component is formulated as follows: 70 parts by weight of polyethylene glycol, 30 parts by weight of polytetrahydrofuran glycol, 3-4 parts by weight of 1,4-butanediol, 0.1-1.5 parts by weight of leveling agent, and 0.05-0.5 parts by weight of wetting agent.

2. The polyurethane waterproof and breathable membrane according to claim 1, characterized in that, The relative molecular weights of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran glycol are all 2000.

3. The polyurethane waterproof and breathable membrane according to claim 1, characterized in that, The preparation process of polyurethane waterproof and breathable membrane includes the following steps: Step 1: Add hydroxyl-terminated alkyl long-chain siloxane monomers, polyethylene glycol, and polypropylene glycol to a reactor. Dehydrate the mixture by passing nitrogen gas through it at 85-95°C until the water content drops below 0.05%. Then add 4,4-diphenylmethane diisocyanate, heat to 70-80°C, and stir the reaction at 200-400 rpm. When the isocyanate content reaches 3.5%-4.0%, cool down and stop the reaction to obtain the isocyanate prepolymer component. Step 2: Prepare the ingredients according to the polyol component formula, and stir and mix them evenly at 800-900 rpm to obtain the polyol component; Step 3: Add the isocyanate prepolymer component and polyol component according to the isocyanate index of 1.03-1.08, as follows: First, stir the polyol component and catalyst at 800-900 rpm for 4-6 minutes, then add the isocyanate prepolymer component and stir evenly. Coat the mixture onto the release film with a coating thickness of 0.2-0.3 mm, and cure it at 100-120℃ for 1-5 minutes to obtain a polyurethane waterproof and breathable membrane.

4. The polyurethane waterproof and breathable membrane according to claim 3, characterized in that, The catalyst used in step three is 1,3,5-tris(dimethylaminopropyl)-1,3,5-hexahydrotriazine, and the amount of the catalyst used is 0.7-1.0 parts by weight.

5. The polyurethane waterproof and breathable membrane according to claim 1, characterized in that, The preparation method of hydroxyl-terminated alkyl long-chain linear siloxane monomers is as follows: One molar equivalent of tetramethyldivinyldisiloxane reacts with two molar equivalents of dimethylphenylsilane in a hydrosilylation reaction to yield a terminal phenylsiloxane monomer. One molar equivalent of a terminal phenylsiloxane monomer undergoes a Friedel-Crafts alkylation reaction with two molar equivalents of undecenol to yield a terminal hydroxyl alkylated long-chain linear siloxane monomer.

6. The polyurethane waterproof and breathable membrane according to claim 1, characterized in that, The preparation method of hydroxyl-terminated alkyl long-chain cage-like siloxane monomers is as follows: One molar equivalent of caged silsesquioxane T8-NH2 reacts with two molar equivalents of phenyl methacrylate in an aminoenyl addition reaction to give a phenyl-terminated caged siloxane monomer. One molar equivalent of a phenyl-terminated caged siloxane monomer is reacted with two molar equivalents of undecenol via Friedel-Crafts alkylation to yield a hydroxyl-terminated alkylated long-chain caged siloxane monomer.

7. A waterproof and breathable composite fabric, characterized in that, The product structure of the waterproof and breathable composite fabric is as follows: polyester high-elastic twill fabric as the outer fabric, hot melt adhesive as the middle layer, and polyurethane waterproof and breathable membrane as described in any one of claims 1-6 as the inner fabric.

8. The waterproof and breathable composite fabric according to claim 7, characterized in that, The hot melt adhesive is either W120 type copolyamide Co-PA hot melt adhesive or A024 type thermoplastic polyurethane hot melt adhesive.

9. The waterproof and breathable composite fabric according to claim 7, characterized in that, The manufacturing process of waterproof and breathable composite fabric is as follows: the fabric, intermediate layer and lining are laminated on a heat press to obtain waterproof and breathable composite fabric; the process parameters of the lamination process are: temperature 120-150℃, pressure 0.3-0.5kPa, and hot pressing time 10-40s.

10. A waterproof and breathable composite fabric according to claim 7, characterized in that, The waterproof and breathable composite fabric is used as a raw material for manufacturing waterproof and breathable clothing.

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