TPU coating pneumatic membrane material and preparation method thereof

Abstract

The invention relates to a TPU coating pneumatic membrane material and a preparation method thereof, belongs to the technical field of square cabins, and solves the problem of poor puncture resistance of a square cabin pneumatic membrane material in the prior art. The fabric comprises an outer layer, an inner layer and a middle layer, the middle layer is a three-dimensional warp knitting fabric layer, the outer layer is a TPU and aramid chopped fiber composite layer, and the inner layer is a TPU mask layer. On the other hand, the invention provides a preparation method of the TPU coating pneumatic membrane material, and the preparation method comprises the following steps: step 1, weaving and forming the three-dimensional warp knitting fabric; step 2, TPU surface modification and interface strengthening; and 3, spraying the inner layer and the outer layer to form a coating. The anti-puncture performance of the pneumatic membrane can be improved, and the anti-puncture performance is improved from 800 N to 1400 N or above.

Description

Technical Field

[0001] The invention relates to the technical field of shelters, and in particular to a TPU coated inflatable membrane material and a preparation method thereof. Background Art

[0002] Due to long-term exposure to sunlight, wind and rain and other natural environments, as well as frequent use and inflation and deflation processes, the performance of the membrane material will gradually decline, such as fading, brittleness, and reduced strength, which will affect the service life. The inflatable membrane material is relatively thin and has poor puncture resistance. It is easy to be punctured or scratched by sharp objects. Once damaged, it may cause internal air pressure leakage, affecting the stability of the membrane structure. Even if it is a small damage, if it is not repaired in time, it may gradually expand under the action of air pressure, causing more serious problems. Summary of the invention

[0003] In view of the above analysis, the embodiments of the present invention aim to provide a TPU coated inflatable membrane material and a preparation method thereof, so as to solve the problem that the current inflatable membrane material of the shelter has poor anti-puncture ability.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] In one aspect of the present invention, there is provided a TPU coated inflatable film material, comprising an outer layer, an inner layer and an intermediate layer;

[0006] The middle layer is a three-dimensional warp knitted fabric layer, the outer layer is a TPU and aramid chopped fiber composite layer, and the inner layer is a TPU mask layer.

[0007] Furthermore, the three-dimensional warp knitted fabric layer is made of polyester.

[0008] Furthermore, the thickness of the outer layer is 100 μm, and the thickness of the inner layer is 50 μm.

[0009] Furthermore, the three-dimensional warp knitted fabric layer includes an upper surface layer, a middle layer and a lower surface layer; the middle layer is a bionic laminated structure; the upper surface layer and the lower surface layer are symmetrically arranged, and the upper surface layer and the lower surface layer are a combination of a mesh structure and a dense structure.

[0010] Furthermore, the bionic laminated structure is a pangolin scale structure or a spider web radial structure; the hardness gradient of the pangolin scale structure is from 90A Shore A for the outer layer to 75A for the inner layer.

[0011] Another aspect of the present invention provides a method for preparing a TPU coated inflatable film material, comprising the following steps:

[0012] Step 1: three-dimensional warp knitted fabric is knitted into shape;

[0013] Step 2: Surface modification and interface strengthening of TPU materials;

[0014] Step 3: The modified TPU material is sprayed onto the upper surface layer and the lower surface layer of the three-dimensional warp knitted fabric layer to complete the preparation.

[0015] Furthermore, in step 2, the surface modification is reinforcing filler modification or polymer blending modification.

[0016] Furthermore, according to the weight percentage of the components, the specific content of the polymer mixed liquid used in the polymer blending modification is: the content of polycarbonate is 15-20%, the content of liquid crystal polymer is 5-10%, and the content of polytetrafluoroethylene is 3-5%.

[0017] Furthermore, the interface strengthening in step 2 is plasma grafting or nano-anchoring layer.

[0018] Furthermore, the treatment conditions of the plasma grafting are: the power of the reaction chamber of the plasma treatment equipment is 300W, and NH 3 Plasma treatment, treatment time is 120s.

[0019] The processing conditions of the nano anchor layer are: coating SiO with a particle size of 50nm 2 Nanoparticle suspensions form mechanically interlocked structures.

[0020] Furthermore, in step 3, the spraying method is gradient spraying; and the spraying process is electrostatic flocking and micro-foaming process.

[0021] Furthermore, the electrostatic flocking is specifically implanted with 1 mm aramid pile heads, and the density of the aramid pile heads is 500 / cm 2 , forming a microscopic obstacle array

[0022] The micro-foaming process has a pore size of 50-200 μm and a foaming rate of 30%.

[0023] Furthermore, in step 1, the internal structure of the three-dimensional warp knitted fabric is woven into a pangolin scale structure, and the structural parameters of the pangolin scale structure are: having a hexagonal laminated unit, the unit side length is 5 mm, the scale inclination angle is 45°, and the laminated thickness is 0.3 mm / layer×3 layers.

[0024] Furthermore, in step 1, the internal structure of the three-dimensional warp knitted fabric is woven into a spider web radial structure; the spider web radial structure uses a density of 25 strands / cm 2 woven from yarn.

[0025] Furthermore, in the step 1, the upper surface structure of the three-dimensional warp knitted fabric includes an upper mesh layer and an upper dense layer; and the lower surface structure includes a lower mesh layer and a lower dense layer.

[0026] Furthermore, the reinforcing filler is a nano-reinforced filler; the nano-reinforced filler is one or more of carbon nanotubes, aramid nanofibers and modified silica;

[0027] Furthermore, according to the weight percentage of the components, in the nano-reinforced filler, the content of carbon nanotubes is 0.5-2%, the content of aramid nanofibers is 3-5%, and the content of modified silicon dioxide is 5-8%.

[0028] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] (1) In the present invention, warp knitted spacer fabric is used as the skeleton material, and the stress is dispersed through three-dimensional support, and the energy absorption rate is 65%. The spacer wire separates the upper and lower surface fabrics to form a stable structure, which can effectively disperse the pressure after inflation and withstand large external forces without deformation; and the three-dimensional structure of the warp knitted spacer fabric makes it difficult for the warp knitted spacer fabric to tear and expand when it is scratched by a sharp object or subjected to local force, thereby improving the durability of the inflation membrane.

[0030] (2) In the present invention, the outer layer is a contact layer and needs to have strong cone puncture resistance. The outer layer is a composite layer of 100 μm TPU and 20% aramid short-cut fibers to form a hard layer, which preferentially consumes puncture energy and increases cone puncture resistance by 50%. The inner layer is an airtight layer and needs to have high air tightness and crack resistance. The inner layer is a 50 μm high-elastic TPU composite film to form a flexible layer to prevent crack penetration, and the air tightness is maintained at more than 95%.

[0031] (3) In the present invention, the single-sided mesh structure and the double-sided mesh structure have more pores and open spaces, providing sufficient filling space for TPU. The upper mesh layer and the lower mesh layer are arranged near the TPU coating, which increases the roughness and specific surface area of ​​the fabric surface, which is beneficial to improve the bonding effect between TPU and the fabric, thereby better achieving filling; the tissue yarns of the upper dense layer and the lower dense layer are arranged closely, with low porosity, and are arranged close to the middle layer, which can effectively prevent TPU from further penetrating downward and losing, thereby ensuring that TPU is retained in the fabric structure and is not easy to fall off or shift.

[0032] (4) In interface strengthening, plasma grafting introduces amino-NH 2 , reacts with the isocyanate group of TPU to form a covalent bond, and the interface binding energy is increased from the original 80J / m 2 Increased to 150J / m 2 ; The nano anchor layer is coated with SiO with a particle size of 50nm 2Nanoparticle suspension forms a mechanical interlocking structure, the peel strength is increased from 60N / cm to 85N / cm, and the puncture failure mode is changed from interface peeling to matrix fracture. Electrostatic flocking is used in the spraying process to implant 1mm aramid pile, and the density of aramid pile is 500 / cm 2 , forming a microscopic obstacle array, the dynamic puncture ability is improved by 33%; the pore size in the micro-foaming process is 50-200μm, the foaming rate is 30%, and the energy is absorbed by the collapse of the pores, and the static pressure puncture force is improved by 22%.

[0033] (5) Compared with the prior art, the pangolin scale structure of the three-dimensional warp knitted fabric of the present invention is composed of a multi-layer structure, and the layers are arranged in an orderly and tight structure in a tile-like overlapping manner. It can change its shape under different external forces and has better protection. The puncture strength is increased by 38%; the spider web radial structure is that the silk threads are relatively dense in the area close to the center, which can better withstand the external concentrated force; while in the edge area, the silk threads are relatively sparse. When subjected to external force, the force can be evenly dispersed along the radial and spiral silk threads to avoid local stress concentration leading to structural damage. The radial high-density yarn density woven into the base fabric is 25 strands / cm 2 , forming a rapid stress dispersion channel, reducing the puncture damage area by 60% and the crack growth rate by 45%.

[0034] (6) In the nano-reinforced filler, carbon nanotubes form a three-dimensional network structure to enhance energy absorption; aramid nanofibers with high modulus bridge crack propagation; and modified silica induces shear yield and increases crack propagation resistance.

[0035] (7) Compared with the prior art, the present invention uses warp knitted spacer fabrics and adds nanofillers such as carbon nanotubes and aramid nanofibers, as well as polymer blending modification such as PC and LCP, which effectively improves the material's puncture resistance. Structurally, a multilayer composite structure and a pangolin scale structure or spider web radial structure with bionic topology optimization are used to disperse stress and inhibit crack propagation. In terms of process, gradient spraying, electrostatic flocking and plasma grafting technologies enhance the interface bonding performance. Compared with the prior art, the present invention has significant improvements in puncture resistance, low temperature tolerance and wet heat stability. It has been determined that the TPU coated inflatable membrane material of this embodiment achieves an increase in puncture resistance from 800N to more than 1400N, while maintaining lightweight, with a surface density of <700g / m 2 .

[0036] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the following content, and some advantages can be obvious from the description or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the text and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0038] Figure 1 It is a schematic structural diagram of the TUP coating inflation membrane material of specific embodiment 1;

[0039] Figure 2 This is a flow chart for preparing the TUP coated inflation membrane material of specific embodiment 2.

[0040] Reference numerals:

[0041] 1-outer layer, 2-inner layer, 3-middle layer, 31-upper surface layer, 311-upper mesh layer, 312-upper dense layer, 32-lower surface layer, 321-lower mesh layer, 322-lower dense layer, 33-middle layer. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0043] Example 1

[0044] A specific embodiment of the present invention, as Figure 1 As shown, a TPU coated inflatable membrane material is disclosed, comprising an outer layer 1, an inner layer 2 and an intermediate layer 3. The intermediate layer 3 is a three-dimensional warp knitted fabric layer, the outer layer 1 is a composite layer of TPU and aramid short-cut fibers, and the inner layer 2 is a TPU mask layer.

[0045] In this embodiment, a three-dimensional warp knitted spacer fabric is used as the skeleton material. The three-dimensional support disperses the stress, and the spacer wire separates the upper and lower surface fabrics to form a stable structure. After inflation, it can effectively disperse the pressure and withstand large external forces without deformation; and the three-dimensional structure of the warp knitted spacer fabric makes it difficult for the warp knitted spacer fabric to tear and expand when it is scratched by a sharp object or subjected to local force, thereby improving the durability of the inflation membrane.

[0046] Exemplarily, the three-dimensional warp knitted fabric layer of the present embodiment is polyester knitting. The three-dimensional warp knitted fabric layer includes an upper surface layer, a lower surface layer and a middle layer. The middle layer structure is a bionic laminated structure, specifically, the bionic laminated structure is a pangolin scale structure or a spider web radial structure. The hardness gradient of the pangolin scale structure is 1 Shore 90A for the outer layer to 275A for the inner layer. The structures of the upper surface layer and the lower surface layer are a combination of a mesh structure and a compact structure.

[0047] Compared with the prior art, the pangolin scale structure of the three-dimensional warp knitted fabric in this embodiment is composed of a multi-layer structure. The layers are arranged in an orderly and tight structure in a shingle-like overlapping manner. It can change its shape under the action of different external forces, has good protection, and effectively improves the puncture strength by 60%. The radial structure of the spider web is that the silk threads are relatively dense in the area close to the center, which can better withstand the external concentrated force; while in the edge area, the silk threads are relatively sparse. When subjected to external force, the force can be evenly dispersed along the radial and spiral silk threads to avoid local stress concentration and structural damage. This embodiment has a weaving density of 25 threads / cm 2 The radial high-density yarn forms a rapid stress dispersion channel, reducing the puncture damage area by 60% and the crack growth rate by 45%.

[0048] In this embodiment, the thickness of the outer layer 1 TPU and aramid short fiber composite layer is set to 100μm, and the thickness of the inner layer 2 TPU coating is 50μm. The outer layer 1 is a contact layer and needs to have strong cone puncture resistance. The outer layer 1 is a composite layer of 100μm TPU and 20% aramid short fiber, forming a hard layer, which preferentially consumes puncture energy and increases cone puncture resistance by 50%. The inner layer 2 is an airtight layer and needs to have high air tightness and crack resistance. The inner layer 2 is set to be a 50μm high-elastic TPU composite film to form a flexible layer to prevent crack penetration, and the air tightness is maintained at more than 95%.

[0049] The TPU-coated inflatable film material of this embodiment achieves an improvement in puncture resistance from 800N to over 1400N while maintaining lightweight with a surface density of <700g / m 2 .

[0050] Example 2

[0051] Another specific embodiment of the present invention, as Figure 2 As shown, a method for preparing a TPU coated inflatable film material is disclosed, which is used to form the TPU coated inflatable film material of Example 1, comprising the following steps:

[0052] Step 1: Weaving a three-dimensional warp knitted fabric layer 3 into shape;

[0053] Step 2: Surface modification and interface strengthening of TPU materials;

[0054] Step 3: The modified TPU material is sprayed onto the upper surface layer 31 and the lower surface layer 32 of the three-dimensional warp knitted fabric layer 3 to complete the preparation.

[0055] In step 1, in order to improve the puncture resistance of the inflatable membrane material, the three-dimensional warp knitted fabric middle layer 33 is woven into a pangolin scale structure or a spider web radial structure through bionic topological optimization. Specifically, the structural parameters of the pangolin scale structure are: a hexagonal laminated unit with a unit size of 5 mm, a scale inclination angle of 45°, and a laminate thickness of 0.3 mm / layer × 3 layers; the spider web radial structure uses a density of 25 strands / cm 2 woven from yarn.

[0056] Considering the bonding ability of the TPU coating and the fabric layer, the surface structure of the three-dimensional warp knitted fabric includes an upper surface layer 31 and a lower surface layer 32. The upper surface layer 31 includes an upper mesh layer 311 and an upper dense layer 312, and the lower surface layer 32 includes a lower mesh layer 321 and a lower dense layer 322. On the one hand, the mesh structure has more pores and open spaces, providing sufficient filling space for TPU; on the other hand, the mesh structure is set near the TPU coating, which increases the roughness and specific surface area of ​​the fabric surface, which is conducive to improving the bonding effect between TPU and fabric, thereby better achieving filling; the dense structure yarns are closely arranged, with low porosity, and are set near the middle layer, which can effectively prevent TPU from further penetrating downward and losing, thereby ensuring that TPU is retained in the fabric structure and is not easy to fall off or shift.

[0057] In step 2, the surface modification is reinforcing filler modification and polymer blending modification.

[0058] In the modification of reinforcing fillers, the basic raw materials of TPU are mixed with reinforcing fillers through a blending process, so that the reinforcing fillers are evenly dispersed in the TPU matrix to form a uniformly dispersed phase composite material.

[0059] Preferably, nano-reinforcement materials are used in the modification of reinforcing fillers, and the nano-reinforcement materials include carbon nanotubes, aramid nanofibers and modified silica.

[0060] Specifically, according to the weight percentage of the components, in the nano-reinforced filler, the content of carbon nanotubes is 0.5-2%, the content of aramid nanofibers is 3-5%, and the content of modified silicon dioxide is 5-8%.

[0061] It should be noted that the content of carbon nanotubes is 0.5-2%, which is used to form a three-dimensional grid structure to enhance energy absorption. The content of aramid nanofibers is 3-5%. Aramid nanofibers are high modulus fibers used to prevent bridging crack propagation. The content of modified silica is 5-8%, which is used to induce shear yield and increase crack propagation resistance.

[0062] Preferably, 1% of carbon nanotubes and 3% of aramid nanofibers are used for synergistic modification, and the puncture strength reaches 1250N while maintaining an elongation at break>400%.

[0063] This embodiment can also adopt polymer blending modification to enhance the interface bonding ability between the TPU coating and the fabric layer. First, the polymer material is dried; in order to facilitate the blending process, it is made into particles with uniform particle size by a granulator; the polymer material is dissolved in an appropriate solvent to form a uniform solution, and then the solutions of different polymers are mixed together, and then the polymer blend is precipitated or solidified by evaporating the solvent.

[0064] Preferably, in the polymer blending modification, the specific content of the modifier in the polymer mixed solution used according to the weight percentage of the components is: the content of polycarbonate is 15-20%, the content of liquid crystal polymer is 5-10%, and the content of polytetrafluoroethylene is 3-5%.

[0065] In this embodiment, the interface strengthening process is a plasma grafting process or a nano-anchoring layer strengthening process.

[0066] Specifically, the processing conditions of the plasma grafting process are: the power of the reaction chamber of the plasma processing equipment is 300W, and NH 3 Plasma treatment, treatment time is 120s. Plasma grafting introduces amino-NH 2 , reacts with the isocyanate group of TPU to form a covalent bond, and the interface binding energy is increased from the original 80J / m 2 Increased to 150J / m 2 .

[0067] The processing conditions of the nano anchor layer are: coating SiO with a particle size of 50nm 2 The nanoparticle suspension forms a mechanical interlocking structure, the peel strength is increased from 60N / cm to 85N / cm, and the puncture failure mode is changed from interface peeling to matrix fracture.

[0068] In step 3, the modified TPU material is sprayed onto the upper surface layer 31 and the lower surface layer 32 of the three-dimensional warp knitted fabric layer 3 to complete the preparation.

[0069] The modified TPU material is sprayed onto the upper surface layer 31 and the lower surface layer 32 in a gradient spraying manner to reduce the coating thickness, which is beneficial to achieving lightweight of the inflatable membrane.

[0070] The mesh layer of the upper surface layer 31 is close to the TPU coating. During spraying, the mesh layer with high porosity has sufficient space for TPU filling. After TPU is filled into the mesh layer, it is blocked in the dense layer, so that the TPU modified material is tightly combined with the upper surface layer 31 and the lower surface layer 32.

[0071] The electrostatic flocking process is used in the TPU spraying process. A flocking machine is used to implant 1 mm aramid piles in the upper surface layer 31 and the lower surface layer 32. The density of the aramid piles is 500 pieces / cm 2During puncture, the softness and elasticity of the villi are used to disperse and conduct the puncture force along the direction of the villi, reducing the risk of the base material being punctured and increasing the dynamic puncture capacity by 33%.

[0072] The micro-foaming process makes the TPU material form a TPU foam material with a microporous structure. The pore size of the micropores is 50-200μm and the foaming rate is 30%. The micro-foaming process forms a uniform microporous structure inside the material, which absorbs energy through the collapse of the pores. When subjected to puncture force, these micropores can disperse the force to a larger area to avoid the force being concentrated on one point, thereby improving the material's ability to resist puncture. The micro-foaming process can increase the static pressure puncture force by 22%.

[0073] After TPU coating was completed, anti-puncture test and environmental adaptability test were performed, and the test data were obtained as shown in Table 1 and Table 2. It can be seen that compared with the prior art, this embodiment has significant improvements in anti-puncture performance, low temperature tolerance and wet heat stability.

[0074] Table 1 Puncture resistance test (test standard ASTM F1342)

[0075]

[0076] Table 2 Environmental adaptability test

[0077] Test conditions Puncture strength retention rate Key Mechanism -40℃ low temperature 89％ TPU glass transition temperature (Tg = -50°C) Humidity and heat aging (85℃ / 85%RH×500h) 83％ <![CDATA[Nano - SiO 2 Inhibiting hydrolysis]]> Oily surface 95％ PTFE modification reduces friction adsorption

[0078] Compared with the existing technology, this embodiment uses warp knitted spacer fabrics and adds nanofillers such as carbon nanotubes and aramid nanofibers, as well as polymer blending modification such as PC and LCP, which effectively improves the material's puncture resistance; in terms of structure, a multi-layer composite structure and a pangolin scale structure or spider web radial structure with bionic topology optimization are used to disperse stress and inhibit crack propagation. In terms of process, gradient spraying, electrostatic flocking and plasma grafting technology enhance the interface bonding performance; compared with the existing technology, this embodiment has significantly improved puncture resistance, low temperature tolerance and wet heat stability.

[0079] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A TPU coated inflatable film material, characterized in that: It comprises an outer layer (1), an inner layer (2) and a middle layer (3); The middle layer (3) is a three-dimensional warp knitted fabric layer, the outer layer (1) is a TPU and aramid chopped fiber composite layer, and the inner layer (2) is a TPU mask layer.

2. The TPU coated inflatable film material according to claim 1, characterized in that: The three-dimensional warp knitted fabric layer is made of polyester.

3. The TPU coated inflatable film material according to claim 1, characterized in that: The thickness of the outer layer (1) is 100 μm, and the thickness of the inner layer (2) is 50 μm.

4. A method for preparing a TPU coated inflatable film material, characterized in that: The following steps are involved: Step 1: Weaving a three-dimensional warp knitted fabric layer (3) into shape; Step 2: Surface modification and interface strengthening of TPU materials; Step 3: The modified TPU material is sprayed onto the upper surface layer (31) and the lower surface layer (32) of the three-dimensional warp knitted fabric layer (3) to complete the preparation.

5. The method for preparing the TPU coated inflatable film material according to claim 4, characterized in that: In the step 2, the surface modification is enhanced filler modification and polymer blending modification.

6. The method for preparing the TPU coated inflatable film material according to claim 5, characterized in that: According to the weight percentage of the components, the specific content of the polymer mixed liquid used in the polymer blending modification is: the content of polycarbonate is 15%-20%, the content of liquid crystal polymer is 5%-10%, and the content of polytetrafluoroethylene is 3%-5%.

7. The method for preparing the TPU coated inflatable film material according to claim 4, characterized in that: The interface strengthening in step 2 is plasma grafting or nano anchoring layer.

8. The method for preparing the TPU coated inflatable film material according to claim 7, characterized in that: The treatment conditions of the plasma grafting are: the power of the reaction chamber of the plasma treatment equipment is 300W, NH3 plasma treatment is used, and the treatment time is 120s; The processing conditions of the nano anchoring layer are: coating a SiO2 nanoparticle suspension with a particle size of 50 nm to form a mechanical interlocking structure.

9. The method for preparing the TPU coated inflatable film material according to claim 4, characterized in that: In step 3, the spraying method is gradient spraying; the spraying process is electrostatic flocking and micro-foaming process.

10. The method for preparing the TPU coated inflatable film material according to claim 9, characterized in that: The electrostatic flocking is specifically to implant aramid piles with a length of 1 mm, and the density of the aramid piles is 500 / cm 2 , forming a microscopic obstacle array; the micro-foaming process has a pore size of 50-200μm and a foaming rate of 30%.

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