A method for preparing waterproof and breathable clothing membrane

Abstract

The invention discloses a method for preparing a waterproof and breathable clothing membrane, which includes: S1, mixing: mixing a hydrophilic polyurethane elastomer with a polytetrafluoroethylene dispersion resin; S2, extruding and calendering a pressed blank: subjecting the paste material to a slaking treatment; S3, stretching and heat setting; S4, preparing a leaching solution S5, dipping and drying, adding a hydrophilic polyurethane elastomer to a polytetrafluoroethylene dispersion resin, the surface tension of a polytetrafluoroethylene-polyurethane composite membrane prepared by a biaxial stretching method is greater than that of a pure polytetrafluoroethylene microporous membrane, and in the subsequent process of impregnating the leaching solution, the leaching solution can be made to penetrate into the membrane pores under normal pressure, retaining a portion of the membrane pores, so that the microporous membrane has good air permeability and moisture permeability, and also improves the tensile strength of the membrane, and the prepared waterproof and breathable clothing membrane is water-resistant, has good air permeability, has a large moisture permeability, and is not easy to delaminate and peel. Adding perfluorosilane to the leaching solution can further improve the water resistance of the membrane.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof and breathable clothing membranes, and in particular to a method for preparing a waterproof and breathable clothing membrane. Background Art

[0002] The surface of polytetrafluoroethylene microporous film is hydrophobic and breathable. The polytetrafluoroethylene microporous film and textile fabric are laminated by lamination technology and can be applied to the textile field to give the product waterproof, moisture permeable, breathable, warm and other functions. However, due to the high porosity of the microporous film, it is easy to absorb salt and oil in human sweat. At the same time, during washing, detergent is adsorbed in the pores of the polytetrafluoroethylene film, resulting in a serious decrease in the water pressure resistance of the film itself. Therefore, as the wearing time increases, there will be problems of water seepage and reduced water pressure resistance of the fabric.

[0003] In order to solve the problem that the water pressure resistance of polytetrafluoroethylene laminated film fabric decreases after multiple washings, a layer of dense polyurethane is coated on the polytetrafluoroethylene microporous film, and the polyurethane layer can effectively improve the water washing resistance of the polytetrafluoroethylene microporous film. However, the polyurethane layer is a dense layer, which will cause the air permeability of the film to seriously decrease. Therefore, in order to solve the above problems, this scheme proposes a method for preparing a waterproof and breathable clothing membrane. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for preparing a waterproof and breathable clothing membrane. A hydrophilic polyurethane elastomer is added to a polytetrafluoroethylene dispersed resin. The surface tension of the polytetrafluoroethylene-polyurethane composite membrane prepared by a biaxial stretching method is greater than that of a pure polytetrafluoroethylene microporous membrane. In the subsequent process of impregnating the leaching liquid, the leaching liquid can penetrate into the membrane pores under normal pressure, retaining a part of the membrane pores, so that the microporous membrane has good air permeability and moisture permeability, and also improves the tensile strength of the membrane. The prepared waterproof and breathable clothing membrane is resistant to water washing, has good air permeability, a large moisture permeability, and is not easy to delaminate and peel. Adding perfluorosilane to the leaching liquid can further improve the water washing resistance of the membrane.

[0005] The present invention also provides a method for preparing the above-mentioned waterproof and breathable clothing membrane, comprising the following steps:

[0006] S1. Mixing: mixing a hydrophilic polyurethane elastomer with a polytetrafluoroethylene dispersion resin, and then adding a lubricant and continuing to mix with the mixture to form a paste-like material;

[0007] S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip;

[0008] S3, stretching and heat setting: after the base tape is degreased, it is longitudinally stretched at a certain speed, then transversely stretched, and then heat-set to obtain a polytetrafluoroethylene-polyurethane composite film;

[0009] S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer, perfluorosilane and a solvent in a certain mass ratio to prepare a coating solution;

[0010] S5, dipping, pressing and drying: dipping the polytetrafluoroethylene-polyurethane composite membrane into the coating solution, then dipping and pressing it with a padder, drying it, and then rolling it up to prepare a waterproof and breathable clothing membrane.

[0011] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the hydrophilic polyurethane elastomer in S1 is specifically one of polyurethane TPU EHT-1190, polyurethane TPU EHT-1195, polyurethane TPU 1180A, polyurethane TPU1185A, polyurethane TPU260D and polyurethane TPU270D.

[0012] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the lubricant in S1 is any one of aviation kerosene, paraffin oil, cyclohexane oil or naphtha, and the number average molecular weight of the polytetrafluoroethylene dispersion resin is 1 million to 10 million.

[0013] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the mass ratio of the hydrophilic polyurethane elastomer, the polytetrafluoroethylene dispersion resin and the lubricant in S1 is 1:10:1 to 1:30:3.

[0014] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the degreasing temperature in the stretching and heat setting in S3 is 130-150°C, the longitudinal stretching multiple is 4-6 times, the transverse stretching multiple is 6-8 times, the stretching temperature is 130-150°C; and the heat setting temperature is 340-360°C.

[0015] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the mass ratio of the hydrophilic polyurethane elastomer, the perfluorosilane and the solvent in S4 is 1:0.05-0.1:50-80.

[0016] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the hydrophilic polyurethane elastomer in S4 is specifically one of polyurethane TPU EHT-1190, polyurethane TPU EHT-1195, polyurethane TPU 1180A, polyurethane TPU1185A, polyurethane TPU260D and polyurethane TPU270D, the perfluorosilane is one of perfluorooctyltrichlorosilane, perfluorodecyltrichlorosilane, perfluorooctyltriethoxysilane, perfluorooctyltrimethoxysilane, perfluorodecyltrimethoxysilane or perfluorodecyltriethoxysilane, and the solvent is specifically one of N,N-dimethylacetamide, N,N-dimethylformamide and N-methylpyrrolidone.

[0017] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the mass ratio of the coating liquid to the polytetrafluoroethylene / polyurethane composite membrane in S5 is 10:1 to 5:1.

[0018] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, the rolling pressure in S5 is 0.2-0.5 MPa, the drying temperature is 140-150° C., and the drying time is 10-20 min.

[0019] According to a method for preparing a waterproof and breathable clothing membrane provided by the present invention, copy the claim 2. Write the beneficial effects of the claim.

[0020] Compared with the prior art, the method for preparing a waterproof and breathable clothing membrane of the present invention adds a hydrophilic polyurethane elastomer to a polytetrafluoroethylene dispersed resin, and the surface tension of the polytetrafluoroethylene-polyurethane composite membrane prepared by a biaxial stretching method is greater than that of a pure polytetrafluoroethylene microporous membrane. In the subsequent process of impregnating the leaching liquid, the leaching liquid can penetrate into the membrane pores under normal pressure, retaining a part of the membrane pores, so that the microporous membrane has good air permeability and moisture permeability, and also improves the tensile strength of the membrane. The prepared waterproof and breathable clothing membrane is resistant to water washing, has good air permeability, a large moisture permeability, and is not easy to delaminate and peel. Adding perfluorosilane to the leaching liquid can further improve the water washing resistance of the membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0022] Figure 1 This is an observation diagram of a waterproof and breathable clothing membrane of the present invention under a microscope. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0024] Embodiment 1:

[0025] Reference Figure 1 The present invention provides a method for preparing a waterproof and breathable clothing membrane, which is prepared according to the following method:

[0026] S1. Mixing: Mix a hydrophilic polyurethane elastomer TPU EHT-1190 with a polytetrafluoroethylene dispersion resin having a number average molecular weight of 1 million, and then add aviation kerosene to continue mixing with the mixture to form a paste-like material. The mass ratio of TPU EHT-1190, polytetrafluoroethylene dispersion resin and aviation kerosene is 1:10:1.

[0027] S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip;

[0028] S3, stretching and heat setting: after degreasing the base tape at 130°C, the base tape is longitudinally stretched 4 times at a certain speed, the longitudinal stretching temperature is 130°C, and then transversely stretched 8 times, the transverse stretching temperature is 150°C, and then heat-set at 340°C to obtain a polytetrafluoroethylene / polyurethane composite film;

[0029] S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer TPU EHT-1195, perfluorooctyltrichlorosilane and N,N-dimethylacetamide in a mass ratio of 1:0.05:50 to prepare a coating solution;

[0030] S5, dipping and drying: the polytetrafluoroethylene-polyurethane composite membrane is dipped in the coating liquid, the mass ratio of the polytetrafluoroethylene-polyurethane composite membrane to the coating liquid is 1:20, and then it is rolled and dried with a padder, the pressure of the padder is 0.2MPa, the drying temperature is 140℃, and the drying time is 20min. Then it is rolled to prepare a waterproof and breathable clothing membrane.

[0031] Embodiment 2:

[0032] A method for preparing a waterproof and breathable clothing membrane is prepared according to the following method:

[0033] S1. Mixing: Mix a hydrophilic polyurethane elastomer TPU EHT-1195 with a polytetrafluoroethylene dispersion resin having a number average molecular weight of 10 million, and then add paraffin oil to continue mixing with the mixture to form a paste-like material. The mass ratio of TPU EHT-1195, polytetrafluoroethylene dispersion resin and paraffin oil is 1:30:3.

[0034] S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip;

[0035] S3, stretching and heat setting: after degreasing the base tape at 150°C, the base tape is longitudinally stretched 6 times at a certain speed, the longitudinal stretching temperature is 150°C, and then transversely stretched 6 times, the transverse stretching temperature is 130°C, and then heat-set at 360°C to obtain a polytetrafluoroethylene-polyurethane composite film;

[0036] S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer TPU EHT-1180A, perfluorodecyltrichlorosilane and N,N-dimethylformamide in a mass ratio of 1:0.1:80 to prepare a coating solution;

[0037] S5, dipping and drying: the polytetrafluoroethylene-polyurethane composite membrane is dipped in the coating liquid, the mass ratio of the polytetrafluoroethylene-polyurethane composite membrane to the coating liquid is 1:10, and then it is rolled and dried with a padder, the pressure of the padder is 0.5MPa, the drying temperature is 150℃, and the drying time is 10min. Then it is rolled to prepare a waterproof and breathable clothing membrane.

[0038] Embodiment three:

[0039] A method for preparing a waterproof and breathable clothing membrane is prepared according to the following method:

[0040] S1. Mixing: Mix a hydrophilic polyurethane elastomer TPU EHT-1180A with a polytetrafluoroethylene dispersion resin having a number average molecular weight of 4 million, and then add cyclohexane oil and continue to mix with the mixture to form a paste-like material. The mass ratio of TPU EHT-1180A, polytetrafluoroethylene dispersion resin and paraffin oil is 1:20:2.

[0041] S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip;

[0042] S3, stretching and heat setting: after degreasing the base tape at 135°C, the base tape is longitudinally stretched 5 times at a certain speed, the longitudinal stretching temperature is 145°C, and then transversely stretched 7 times, the transverse stretching temperature is 135°C, and then heat-set at 345°C to obtain a polytetrafluoroethylene-polyurethane composite film;

[0043] S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer TPU 1185A, perfluorooctyl triethoxysilane and N-methyl pyrrolidone in a mass ratio of 1:0.06:60 to prepare a coating solution;

[0044] S5, dipping and drying: the polytetrafluoroethylene-polyurethane composite membrane is dipped in the coating liquid, the mass ratio of the polytetrafluoroethylene-polyurethane composite membrane to the coating liquid is 1:15, and then it is rolled and dried with a padder, the pressure of the padder is 0.3MPa, the drying temperature is 145℃, and the drying time is 17min. Then it is rolled to prepare a waterproof and breathable clothing membrane.

[0045] Embodiment 4:

[0046] A method for preparing a waterproof and breathable clothing membrane is prepared according to the following method:

[0047] S1. Mixing: Mix a hydrophilic polyurethane elastomer TPU 1185A with a polytetrafluoroethylene dispersion resin having a number average molecular weight of 8 million, and then add naphtha to continue mixing with the mixture to form a paste-like material. The mass ratio of TPU 1185A, polytetrafluoroethylene dispersion resin and naphtha is 1:25:2.

[0048] S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip;

[0049] S3, stretching and heat setting: after degreasing the base tape at 140°C, longitudinally stretch it 5.5 times at a certain speed, the longitudinal stretching temperature is 148°C, and then transversely stretch it 7.5 times, the transverse stretching temperature is 142°C, and then heat setting is performed at 350°C to obtain a polytetrafluoroethylene-polyurethane composite film;

[0050] S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer TPU 260D, perfluorooctyltrimethoxysilane and N,N-dimethylformamide in a mass ratio of 1:0.08:70 to prepare a coating solution;

[0051] S5, dipping and drying: the polytetrafluoroethylene-polyurethane composite membrane is dipped in the coating liquid, the mass ratio of the polytetrafluoroethylene-polyurethane composite membrane to the coating liquid is 1:12, and then it is rolled and dried with a padder, the pressure of the padder is 0.4MPa, the drying temperature is 148℃, and the drying time is 14min. Then it is rolled to prepare a waterproof and breathable clothing membrane.

[0052] Comparative Example:

[0053] Comparative Example 1 is a waterproof and breathable clothing membrane, which is different from Example 1 in that an equal amount of polytetrafluoroethylene dispersed resin is used instead of the hydrophilic polyurethane elastomer in the S1 mixing step.

[0054] Comparative Example 2 is a waterproof and breathable clothing membrane, which is different from Example 1 in that an equal amount of hydrophilic polyurethane elastomer is used instead of perfluorosilane in step S4.

[0055] Comparative Example 3 is a waterproof and breathable clothing membrane, which is different from Example 1 in that an equal amount of polytetrafluoroethylene dispersion resin is used in place of the hydrophilic polyurethane elastomer in the S1 mixing step, and there are no S4 and S5 steps.

[0056] Comparative Example 4 is a waterproof and breathable clothing membrane, which differs from Example 1 in that an equal amount of polytetrafluoroethylene dispersed resin is used instead of hydrophilic polyurethane elastomer in step S1 mixing, and an equal amount of hydrophilic polyurethane elastomer is used instead of perfluorosilane in step S4.

[0057] Comparative Example 5 is a waterproof and breathable clothing membrane, which differs from Example 1 in that steps S4 and S5 are not included.

[0058] Performance testing

[0059] Water pressure test:

[0060] The YG(B)812T water permeability tester was used to test the hydrostatic pressure resistance of the membrane in accordance with the GB / T4744-2013 "Testing and evaluating the waterproof performance of textiles" test standard. The washing procedure was tested in accordance with the GB / T8629-2017 "Household washing and drying procedures for textile testing" test standard, using standard detergent 4 and A hanging drying conditions.

[0061] Water vapor transmission test:

[0062] The test was carried out in accordance with the test standard GB / T 12704.2-2009 “Test method for water vapor permeability of textile fabrics”.

[0063] Air permeability test:

[0064] The test was carried out in accordance with the test standard GB / T5453-1997 “Determination of Air Permeability of Textile Fabrics”, and the test pressure difference was 500Pa.

[0065] Mechanical properties test:

[0066] The tensile properties and elongation at break of the antibacterial, waterproof and breathable clothing membrane in this application were tested according to the method in GB / T 1040.3-2006 "Determination of tensile properties of plastics". The test sample width was 20 mm, length was 100 mm, clamping distance was 50 mm, tensile speed was 100 mm / min, each group of samples was tested five times, and the average value was taken.

[0067] Table 1 Water pressure resistance, moisture permeability and air permeability test results

[0068]

[0069] Table 2 Mechanical properties test results

[0070] Average breaking strength (N) Average elongation (%) Example 1 11.20 89.40 Example 2 11.55 92.72 Example 3 11.94 90.11 Example 4 11.48 89.43 Comparative Example 1 6.22 91.26 Comparative Example 2 11.30 89.67 Comparative Example 3 6.45 89.23 Comparative Example 4 6.89 88.62 Comparative Example 5 7.44 90.70

[0071] Analysis of test results:

[0072] Compared with Example 1 and Comparative Example 1, the moisture permeability and air permeability of Example 1 are better than those of Comparative Example 1, because no hydrophilic polyurethane elastomer is added when preparing the polytetrafluoroethylene microporous membrane in Comparative Example 1, the surface tension of the polytetrafluoroethylene microporous membrane is low, and the coating liquid cannot penetrate into the membrane pores, and can only be attached to the surface of the polytetrafluoroethylene microporous membrane to form a dense polyurethane layer, resulting in the clothing membrane being airtight; and due to the presence of the dense polyurethane layer in Comparative Example 1, the water vapor diffusion mechanism is dissolution diffusion, so the moisture permeability is small, while in Example 1, the coating liquid penetrates into the interior of the polytetrafluoroethylene microporous membrane and is wrapped on the fiber net, the micropores inside the membrane are not completely filled, and a part of the pores are retained, and water vapor can penetrate the pores. The diffusion of water vapor belongs to the micropore diffusion mechanism, so the moisture permeability is large. In addition, in Comparative Example 1, since the polyurethane coating liquid cannot penetrate into the pores of the polytetrafluoroethylene membrane, the tensile strength of the membrane is low.

[0073] Comparing Example 1 with Comparative Example 2, the water pressure resistance of Example 1 after 20 water washings is better than that of Comparative Example 2, because the addition of low surface energy perfluorosilane in the laminating solution can improve the water wash resistance of the clothing film.

[0074] Comparing Example 1 with Comparative Example 3, the water pressure resistance of the pure PTFE microporous membrane in Comparative Example 3 is sharply reduced after 20 water washings. This is because the PTFE microporous membrane adsorbs a large amount of surfactant during the multiple washing processes, making the membrane surface hydrophilic, and thus the water pressure resistance is almost 0.

[0075] Comparing Example 1 with Comparative Example 4, the moisture permeability and air permeability of Example 1 are better than those of Comparative Example 4, because no hydrophilic polyurethane elastomer is added when preparing the polytetrafluoroethylene microporous membrane in Comparative Example 4, the surface tension of the polytetrafluoroethylene microporous membrane is low, and the coating liquid can only adhere to the surface of the microporous membrane to form a dense polyurethane layer, resulting in the clothing membrane being airtight and having low moisture permeability.

[0076] Comparing Example 1 with Comparative Example 5, the water pressure resistance of the polytetrafluoroethylene-polyurethane composite membrane in Comparative Example 5 is sharply reduced after 20 water washings. This is because the PTFE microporous membrane adsorbs a large amount of surfactant during multiple washings, making the membrane surface hydrophilic.

[0077] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A method for preparing a waterproof and breathable clothing membrane, characterized in that: The following steps are involved: S1. Mixing: mixing a hydrophilic polyurethane elastomer with a polytetrafluoroethylene dispersion resin, and then adding a lubricant and continuing to mix with the mixture to form a paste-like material; S2, green sheet extrusion and calendering: the paste material is ripened, pre-pressed into a green sheet in a green sheet press, extruded through an extruder to obtain a rod-shaped material, and then calendered on a calender to obtain a base strip; S3, stretching and heat setting: after the base tape is degreased, it is longitudinally stretched at a certain speed, then transversely stretched, and then heat-set to obtain a polytetrafluoroethylene-polyurethane composite film; S4, preparing a coating solution: mixing a hydrophilic polyurethane elastomer, perfluorosilane and a solvent in a certain mass ratio to prepare a coating solution; S5, dipping, pressing and drying: dipping the polytetrafluoroethylene-polyurethane composite membrane into the coating solution, then dipping and pressing it with a padder, drying it, and then rolling it up to prepare a waterproof and breathable clothing membrane.

2. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The hydrophilic polyurethane elastomer in S1 is specifically one of polyurethane TPU EHT-1190, polyurethane TPU EHT-1195, polyurethane TPU 1180A, polyurethane TPU 1185A, polyurethane TPU260D and polyurethane TPU270D.

3. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The lubricant in S1 is any one of aviation kerosene, paraffin oil, cyclohexane oil or naphtha, and the number average molecular weight of the polytetrafluoroethylene dispersion resin is 1 million to 10 million.

4. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The mass ratio of the hydrophilic polyurethane elastomer, the polytetrafluoroethylene dispersion resin and the lubricant in S1 is 1:10:1 to 1:30:

3.

5. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: In the stretching and heat setting in S3, the degreasing temperature is 130-150°C, the longitudinal stretching multiple is 4-6 times, the transverse stretching multiple is 6-8 times, the stretching temperature is 130-150°C; and the heat setting temperature is 340-360°C.

6. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The mass ratio of the hydrophilic polyurethane elastomer, perfluorosilane and solvent in S4 is 1:0.05-0.1:50-80.

7. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The hydrophilic polyurethane elastomer in S4 is specifically one of polyurethane TPU EHT-1190, polyurethane TPU EHT-1195, polyurethane TPU 1180A, polyurethane TPU 1185A, polyurethane TPU260D and polyurethane TPU270D, the perfluorosilane is one of perfluorooctyltrichlorosilane, perfluorodecyltrichlorosilane, perfluorooctyltriethoxysilane, perfluorooctyltrimethoxysilane, perfluorodecyltrimethoxysilane or perfluorodecyltriethoxysilane, and the solvent is specifically one of N,N-dimethylacetamide, N,N-dimethylformamide and N-methylpyrrolidone.

8. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: The mass ratio of the coating liquid to the polytetrafluoroethylene / polyurethane composite film in S5 is 10:1 to 5:

1.

9. The method for preparing a waterproof and breathable clothing membrane according to claim 1, characterized in that: In the S5, the rolling pressure is 0.2-0.5 MPa, the drying temperature is 140-150° C., and the drying time is 10-20 min.

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