Thermoplastic polyurethane composite fabric and method of making same

Abstract

The application relates to a thermoplastic polyurethane composite fabric and a preparation method thereof, in particular to the technical field of film composite fabrics, and the thermoplastic polyurethane composite fabric comprises a base fabric and a TPU / FEP double-component nanofiber film which is laminated on the base fabric through an adhesive layer, wherein the TPU / FEP double-component nanofiber film is spun by using a TPU spinning solution and an FEP spinning solution as raw materials, using a receiving roller subjected to ultrasonic oscillation treatment as a receiving template, and through multi-needle mixed electrostatic spinning. The composite fabric provided by the application has excellent tear resistance, and the waterproof performance is improved compared with traditional TPU film-coated fabrics.

Description

Technical Field

[0001] The invention belongs to the technical field of film composite fabrics, and particularly relates to a thermoplastic polyurethane composite fabric and a preparation method thereof. Background Art

[0002] Fabrics used in outdoor clothing are generally required to be waterproof and breathable. The so-called waterproof and breathable performance means that the fabric is not penetrated by water under a certain pressure of water. At the same time, the sweat vapor emitted by the human body can diffuse through the fabric and does not accumulate and condense between the body surface and plants. The purpose is to improve the wearing comfort of the fabric. At present, the waterproof and breathable performance of the fabric is mostly improved by lamination.

[0003] Thermoplastic polyurethane (TPU) has high strength and elasticity, good vibration and fatigue resistance, strong wear resistance, excellent resistance to chemicals and oils, excellent resistance to oxidation and radiation, and high impact resistance. The nanofiber membrane prepared by electrospinning it has excellent moisture permeability and is a common coating material used for outdoor clothing fabrics. However, in practice, its waterproof performance is unsatisfactory. Currently, there are reports on combining polyvinylidene fluoride (PVDF) with thermoplastic polyurethane (TPU) to improve the waterproof performance of nanofiber membranes. In addition, as people's requirements for waterproof and breathable properties continue to increase, how to improve existing materials to obtain coating materials with even better physical and mechanical properties has positive research significance. Summary of the Invention

[0004] The purpose of the present invention is to provide a thermoplastic polyurethane composite fabric and a preparation method thereof in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] As a first aspect of the present invention, the present invention provides a thermoplastic polyurethane composite fabric, which includes a base fabric and a TPU / FEP two-component nanofiber membrane laminated on the base fabric by an adhesive, wherein the TPU / FEP two-component nanofiber membrane is made of TPU spinning solution and FEP spinning solution as raw materials, and is spun by multi-needle mixed electrospinning using a receiving roller treated with ultrasonic oscillation as a receiving template.

[0007] As a further optimization solution of the present invention, the mass ratio of TPU to FEP in the TPU / FEP two-component nanofiber membrane is (2-6):1.

[0008] As a further optimization solution of the present invention, the adhesive is a reactive polyurethane hot melt adhesive or a copolyamide adhesive film.

[0009] As a further optimization solution of the present invention, the base fabric is pure cotton fabric or a blended cotton fabric obtained by blending cotton fiber and polyester in an equal mass ratio.

[0010] As a further optimized solution of the present invention, the concentration of the TPU spinning solution and the FEP spinning solution is 8-12 wt %.

[0011] As a second aspect of the present invention, the present invention also provides a method for preparing any of the above-mentioned thermoplastic polyurethane composite fabrics, comprising the following steps:

[0012] (1) Add TPU powder and FEP (fluoroethylene propylene) powder to a solvent and stir at room temperature to obtain a uniform and transparent TPU spinning solution and FEP spinning solution, respectively, for later use;

[0013] (2) Using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, a receiving roller subjected to ultrasonic oscillation treatment is used as a receiving template, and a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane;

[0014] (3) The TPU / FEP two-component nanofiber membrane obtained in step (2) is laminated and compounded on the base fabric using an adhesive to obtain the thermoplastic polyurethane composite fabric.

[0015] As a further optimized solution of the present invention, in step (1), the solvent is a mixed solution of N,N-dimethylformamide and acetone in a mass ratio of 7:3.

[0016] As a further optimization scheme of the present invention, in the step (2), the spinning voltage is 25-35 kV, the hot pressing temperature is 130-150 ° C, the hot pressing time is 5-10 min, the steam is silicic acid steam with a concentration of 2-6 wt%, and the steam volume is 10-30 mL / s.

[0017] As a further optimization solution of the present invention, in step (2), the process parameters of the ultrasonic oscillation treatment are an ultrasonic frequency of 15-25 kHz and an ultrasonic electric power of 10-100 W.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention prepares a thermoplastic polyurethane composite fabric by laminating a TPU / FEP two-component nanofiber membrane onto a composite base fabric with an adhesive. Since FEP is added to the nanofiber membrane, the thermoplastic polyurethane composite fabric has excellent tear resistance due to the good strength performance of the FEP material, and at the same time, it has improved waterproof performance compared to traditional TPU coated fabrics.

[0020] (2) When preparing the TPU / FEP two-component nanofiber membrane, the present invention applies ultrasonic oscillation treatment to the receiving roller that receives the nanofibers and combines it with silica vapor to steam hot press the membrane sample, which is beneficial to improving the surface structure of the membrane sample and optimizing the pore structure of the membrane sample, thereby improving the moisture permeability of the fabric to a certain extent. DETAILED DESCRIPTION

[0021] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0022] In the following examples, any method not specified may be carried out according to conventional methods, and the materials and reagents used may be obtained through commercial channels unless otherwise specified.

[0023] Example 1

[0024] This embodiment provides a method for preparing a thermoplastic polyurethane composite fabric, comprising the following steps:

[0025] (1) TPU powder and FEP (fluoroethylene propylene) powder were added to a mixed solution of N,N-dimethylformamide and acetone in a mass ratio of 7:3, and stirred at room temperature for 4 hours at a speed of 60 r / h to obtain uniform and transparent TPU spinning solution and FEP spinning solution for standby use. The concentration of the TPU spinning solution and FEP spinning solution was 8 wt%;

[0026] (2) Using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, a receiving roller subjected to ultrasonic oscillation treatment is used as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane, the hot pressing temperature is 130 ° C, the hot pressing pressure is 2 MPa, the hot pressing time is 10 min, the steam is silicic acid steam with a concentration of 2 wt%, the steam volume is 30 mL / s, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 4:1;

[0027] (3) The TPU / FEP two-component nanofiber membrane obtained in step (2) is laminated on pure cotton using an adhesive to obtain the thermoplastic polyurethane composite fabric, wherein the adhesive is a reactive polyurethane hot melt adhesive, the adhesive application method is hot melt transfer, and the adhesive application amount is 5g / m 2, the gluing temperature is 100℃, the pressure is 2MPa, the processing conditions are 25℃, the humidity is 55%, and the curing time is 24h.

[0028] Example 2

[0029] This embodiment provides a method for preparing a thermoplastic polyurethane composite fabric, comprising the following steps:

[0030] (1) TPU powder and FEP powder were added to a mixed solution of N, N-dimethylformamide and acetone in a mass ratio of 7:3, and stirred at room temperature for 4 hours at a speed of 60 r / h to obtain uniform and transparent TPU spinning solution and FEP spinning solution for standby use. The concentration of the TPU spinning solution and FEP spinning solution was 12 wt%;

[0031] (2) Using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, a receiving roller subjected to ultrasonic oscillation treatment is used as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane, the hot pressing temperature is 150 ° C, the hot pressing time is 5 min, the hot pressing pressure is 2 MPa, the steam is silicic acid steam with a concentration of 6 wt%, the steam volume is 10 mL / s, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 2:1;

[0032] (3) The TPU / FEP two-component nanofiber membrane obtained in step (2) is laminated and compounded on a blended cotton fabric obtained by blending cotton fiber and polyester in an equal mass ratio using an adhesive to obtain the thermoplastic polyurethane composite fabric, wherein the adhesive is a copolyamide adhesive mesh, the adhesive is applied by hot melt transfer, and the adhesive amount is 12 g / m 2 , the hot pressing temperature is 130℃, the pressure is 2MPa, and the processing time is 20s.

[0033] Example 3

[0034] This embodiment provides a method for preparing a thermoplastic polyurethane composite fabric, comprising the following steps:

[0035] (1) TPU powder and FEP powder were added to a mixed solution of N, N-dimethylformamide and acetone in a mass ratio of 7:3, and stirred at room temperature for 4 hours at a speed of 60 r / h to obtain uniform and transparent TPU spinning solution and FEP spinning solution for standby use. The concentration of the TPU spinning solution and FEP spinning solution was 10 wt%;

[0036] (2) Using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, a receiving roller subjected to ultrasonic oscillation treatment is used as a receiving template, the ultrasonic frequency is 15 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane, the hot pressing temperature is 130 ° C, the hot pressing time is 10 min, the hot pressing pressure is 2 MPa, the steam is silicic acid vapor with a concentration of 4 wt%, the steam volume is 20 mL / s, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 6:1;

[0037] (3) The TPU / FEP two-component nanofiber membrane obtained in step (2) is laminated on a pure cotton fabric using an adhesive to obtain the thermoplastic polyurethane composite fabric, wherein the adhesive is a reactive polyurethane hot melt adhesive, the adhesive application method is hot melt transfer, and the adhesive application amount is 5g / m 2 , the gluing temperature is 100℃, the pressure is 2MPa, the processing conditions are 25℃, the humidity is 55%, and the curing time is 24h.

[0038] Verification test

[0039] 1. In order to explore the effect of the composition of the nanofiber membrane on the performance of the composite fabric, the component composition and mass ratio of the nanofiber membrane were adjusted according to Table 1, and the thermoplastic polyurethane composite fabric AG was prepared according to the preparation method given in Example 1, which was recorded as fabric AG.

[0040] Table 1. Composition design of nanofiber membrane

[0041]

[0042]

[0043] First, the tear strength of fabric AG was tested according to GB / T3917-1:2009 "Tear properties of fabrics - Part 1 - Determination of tear strength by impact pendulum method".

[0044] Then the contact angle and hydrostatic pressure resistance tests were conducted on fabric AG.

[0045] Contact angle measurements were performed according to DB44T 1872—2016, "Textile Surface Wetting Properties - Contact Angle Method." A 5 μL drop of deionized water was placed on the surface of the fabric and allowed to sit for 30 seconds. The contact angle was calculated using a five-point fitting method. Five different locations were tested on each specimen, and the results were averaged.

[0046] The hydrostatic pressure resistance test adopts the direct pressurization method. The fabric is placed on the test clamp and the pressure is continuously increased at a rate of 6kPa / min. When water seepage appears at three points on the fabric surface, the pressure value is recorded.

[0047] The results are shown in Table 2.

[0048] Table 2. Test results statistics

[0049]

[0050] It can be seen from Table 2 that with the increase of FEP content in the nanofiber membrane, the tear strength of the fabric increases. In addition, at the same mass ratio, FEP is comparable to PVDF in improving the tear resistance of the fabric, but slightly better than PTFE.

[0051] The contact angle and hydrostatic pressure resistance data show that increasing the FEP content in the nanofiber membrane improves the fabric's water resistance. At the same weight ratio, FEP is more effective at improving the fabric's water resistance than PVDF and PTFE. This is presumably because FEP is superior to PVDF and PTFE in improving the membrane structure of the two-component nanofiber membrane.

[0052] 2. In order to explore the effect of the preparation method of nanofiber membrane on the performance of composite fabrics, the following comparative examples were set up:

[0053] Comparative Example 1

[0054] This comparative example provides a method for preparing a thermoplastic polyurethane composite fabric, which is different from Example 1 in step (2): the TPU spinning solution and FEP spinning solution prepared in step (1) are used as raw materials, a receiving roller that is not subjected to ultrasonic oscillation treatment is used as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning. The membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane, the hot pressing temperature is 130°C, the hot pressing time is 10 min, the steam is silicic acid vapor with a concentration of 2 wt%, the steam volume is 30 mL / s, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 4:1.

[0055] Comparative Example 2

[0056] This comparative example provides a method for preparing a thermoplastic polyurethane composite fabric, which is different from Example 1 in step (2): using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, and using a receiving roller subjected to ultrasonic oscillation treatment as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning. The membrane sample is hot-pressed to obtain a TPU / FEP two-component nanofiber membrane, the hot-pressing temperature is 130°C, and the hot-pressing time is 10 min. The mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 4:1.

[0057] Comparative Example 3

[0058] This comparative example provides a method for preparing a thermoplastic polyurethane composite fabric, which is different from Example 1 in step (2): using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, and using a receiving roller subjected to ultrasonic oscillation treatment as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane, the hot pressing temperature is 130°C, the hot pressing time is 10 min, the steam is water vapor, the steam volume is 30 mL / s, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 4:1.

[0059] Comparative Example 4

[0060] This comparative example provides a method for preparing a thermoplastic polyurethane composite fabric, which is different from Example 1 in step (2): using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, using a receiving roller that is not subjected to ultrasonic oscillation treatment as a receiving template, the ultrasonic frequency is 25 kHz, the ultrasonic electric power is 50 W, the spinning voltage is 35 kV, and a membrane sample is obtained by multi-needle mixed electrospinning. The membrane sample is hot-pressed to obtain a TPU / FEP two-component nanofiber membrane, the hot-pressing temperature is 130°C, the hot-pressing time is 10 min, and the mass ratio of TPU to FEP in the obtained TPU / FEP two-component nanofiber membrane is 4:1.

[0061] The thermoplastic polyurethane composite fabrics prepared in Comparative Examples 1-4 are denoted as fabrics ad.

[0062] First, the antifouling performance of fabrics A and ad was tested. The test method was to take the fabric and cut it from its non-edge position to obtain a 30 cm × 12 cm specimen. Referring to GB / T 30159.1-2013 "Test and evaluation of the antifouling performance of textiles Part 1: Stain resistance", the specimens were tested using the liquid stain method. The specific process was as follows: two layers of filter paper were placed on a smooth horizontal surface, and the specimen was placed flatly on the filter paper with the front side facing up. Approximately 0.05 mL of soy sauce liquid was dripped onto each of the three locations of the specimen using a dropper, with the distance between each drop being at least 50 mm. During dripping, the dropper tip was approximately 6 mm from the specimen surface. After the specimen was allowed to stand for 30 seconds, each drop was observed at a viewing angle of approximately 45° and rated. The rating criteria are shown in Table 3 below.

[0063] Table 3. Contamination levels

[0064]

[0065] The results are shown in Table 4.

[0066] Table 4. Test results statistics

[0067]

[0068] As can be seen from the table, the preparation method of the nanofiber membrane has a certain influence on the antifouling performance of the fabric. When preparing the nanofiber membrane, the membrane sample is steam-pressed with 2wt% silicic acid vapor to reduce the surface energy of the membrane, thereby improving the antifouling performance of the nanofiber membrane. In addition, from the comparison of fabric A and fabric a, it can be seen that applying ultrasonic oscillation treatment to the receiving roller that receives the nanofibers when preparing the nanofiber membrane also has a positive effect on improving the antifouling performance of the fabric.

[0069] Then, the moisture permeability of fabric A and fabric ad was tested.

[0070] The moisture permeability test was conducted on the samples using the FX3180 moisture permeability tester according to the national standard GB / T12704.1-2009(a). During the test, the temperature was 38°C, the humidity was 90.0%, the air flow rate was 0.5m / s, and the test area was 25.0cm. 2 Before testing, the test chamber must be pre-humidified. After automatic humidity adjustment, the instrument begins the moisture permeability test, automatically recording moisture permeability data once every hour for a total of two times. After the experiment is completed, the moisture permeability data of the samples is manually recorded. The final data for each sample group is the average of 10 sets of experimental data.

[0071] Furthermore, the porosity of the membrane samples used for fabric A and fabrics ad was tested. The membrane samples were cut into squares of 2 cm × 2 cm, their mass was weighed using an electronic balance, and their thickness was measured using a measuring instrument. The apparent density and porosity of the membrane samples were calculated using the following formula:

[0072] Where ρ1 is the apparent density (g / cm 3 ); m is the membrane mass (g); h is the membrane thickness (mm); s is the membrane area (cm 2 ); η = porosity; ρ2 is the raw material density (g / cm 3 ).

[0073] The results are shown in Table 5.

[0074] Table 5. Test results statistics

[0075]

[0076] As can be seen from the table, the preparation method of nanofiber membrane has a certain influence on the antifouling performance of the fabric. When preparing the nanofiber membrane, ultrasonic oscillation treatment is applied to the receiving roller that receives the nanofibers, and the membrane sample is steam-pressed with 2wt% silica vapor, which is beneficial to improving the surface structure of the membrane sample and optimizing the pore structure of the membrane sample. Judging from the test data of the porosity of the membrane sample, the use of ultrasonic oscillation treatment combined with silica vapor treatment has a positive effect on improving the porosity of the membrane sample, thereby improving the moisture permeability of the fabric to a certain extent.

[0077] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A thermoplastic polyurethane composite fabric, characterized by: The thermoplastic polyurethane composite fabric includes a base fabric and a TPU / FEP two-component nanofiber membrane laminated on the base fabric by an adhesive, wherein the mass ratio of TPU to FEP in the TPU / FEP two-component nanofiber membrane is (2-6):1; Among them, the TPU / FEP two-component nanofiber membrane is made of TPU spinning solution and FEP spinning solution as raw materials, and a receiving roller treated with ultrasonic oscillation is used as a receiving template to obtain a membrane sample by multi-needle mixed electrospinning. The membrane sample is steam hot-pressed to obtain a TPU / FEP two-component nanofiber membrane. The spinning voltage is 25-35kV, the hot-pressing temperature is 130-150°C, and the hot-pressing time is 5-10min. The steam is silicic acid vapor with a concentration of 2-6wt%, the steam volume is 10-30mL / s, and the concentration of the TPU spinning solution and the FEP spinning solution is 8-12wt%.

2. The thermoplastic polyurethane composite fabric according to claim 1, characterized in that: The adhesive is a reactive polyurethane hot melt adhesive or a copolyamide adhesive film.

3. The thermoplastic polyurethane composite fabric according to claim 1, characterized in that: The base fabric is pure cotton fabric or a blended cotton fabric obtained by blending cotton fiber and polyester in an equal mass ratio.

4. A method for preparing a thermoplastic polyurethane composite fabric according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Add TPU powder and FEP powder to the solvent and stir at room temperature to obtain uniform and transparent TPU spinning solution and FEP spinning solution respectively, and set aside; (2) Using the TPU spinning solution and FEP spinning solution prepared in step (1) as raw materials, and using a receiving roller subjected to ultrasonic oscillation as a receiving template, a membrane sample is obtained by multi-needle mixed electrospinning, and the membrane sample is subjected to steam hot pressing to obtain a TPU / FEP two-component nanofiber membrane; (3) The TPU / FEP two-component nanofiber membrane obtained in step (2) is laminated onto a base fabric using an adhesive to obtain the thermoplastic polyurethane composite fabric.

5. The method for preparing a thermoplastic polyurethane composite fabric according to claim 4, wherein: In the step (1), the solvent is a mixed solution of N,N-dimethylformamide and acetone in a mass ratio of 7:

3.

6. The method for preparing a thermoplastic polyurethane composite fabric according to claim 4, wherein: In the step (2), the process parameters of the ultrasonic oscillation treatment are an ultrasonic frequency of 15-25 kHz and an ultrasonic electric power of 10-100 W.

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