Waterproof tpu film and preparation process thereof

Abstract

This application relates to a film, specifically disclosing a waterproof TPU film and its preparation process. A waterproof TPU film includes a TPU film with a moisture barrier layer disposed on it, and a thermal insulation layer disposed between the moisture barrier layer and the TPU film. The moisture barrier layer comprises the following components in parts by weight: 70-90 parts of elastic polyurethane, 5-15 parts of hydrophobic fluorinated polyurethane, and 10-20 parts of filler. The filler comprises boron nitride, ethanol, and dimethylvinylethoxysilane. The TPU film of this application exhibits good waterproof performance.

Description

Technical Field

[0001] This application relates to a film, and more particularly to a waterproof TPU film and its preparation process. Background Technology

[0002] TPU film is made from TPU granules through processes such as calendering, casting, blown film production, and coating. TPU not only possesses excellent high tensile strength, high tear strength, toughness, and aging resistance, but it is also a mature and environmentally friendly material. However, commonly used TPU films are prone to water vapor penetration, resulting in poor waterproof performance during use. Summary of the Invention

[0003] To improve the waterproof performance of TPU films, this application provides a waterproof TPU film and its preparation process.

[0004] Firstly, this application provides a waterproof TPU film, which adopts the following technical solution:

[0005] A waterproof TPU film includes a TPU film with a moisture barrier layer disposed on the TPU film and a heat insulation layer disposed between the moisture barrier layer and the TPU film. The raw material of the moisture barrier layer includes the following components in parts by weight: 70-90 parts of elastic polyurethane, 5-15 parts of hydrophobic fluorinated polyurethane, and 10-20 parts of filler. The raw material of the filler includes: boron nitride, ethanol, and dimethylvinylethoxysilane.

[0006] By employing the above technical solution, ethanol is used as a solvent, and boron nitride is modified with dimethylvinylethoxysilane, allowing boron nitride to be uniformly dispersed in the moisture barrier layer and forming a rough structure. Furthermore, dimethylvinylethoxysilane can couple elastic polyurethane with hydrophobic fluorinated polyurethane to form a sieve structure, which can block water vapor molecules in the gas. The hydrophobic fluorinated polyurethane can improve the hydrophobicity of the moisture barrier layer, and the rough structure allows water vapor blocked on the surface to escape, thus giving the moisture barrier layer water permeability resistance. The addition of a thermal insulation layer can reduce the liquefaction of water vapor in the air due to temperature differences. Therefore, the combination of the thermal insulation layer and the moisture barrier layer improves the waterproof performance of the TPU film.

[0007] In one specific implementation, the method for preparing the filler includes the following steps:

[0008] Dimethylvinylethoxysilane, ethanol, and water are stirred and mixed evenly to obtain a spraying solution; boron nitride is stirred, and during the stirring process, the spraying solution is sprayed onto the boron nitride, and then dried to obtain the filler.

[0009] By adopting the above technical solution, dimethylvinylethoxysilane is first dissolved in ethanol, and then sprayed onto the surface of boron nitride and dried. The dimethylvinylethoxysilane coats the surface of boron nitride, thus completing the modification of boron nitride and obtaining the filler.

[0010] In one specific implementation, the weight ratio of the dimethylvinylethoxysilane to the boron nitride is 1:(65-75).

[0011] By adopting the above technical solution, this application further specifies the ratio of dimethylvinylethoxysilane to boron nitride, thereby enabling dimethylvinylethoxysilane to better coat boron nitride and thus improving the modification effect of boron nitride.

[0012] In one specific implementation, the weight ratio of the hydrophobic fluorinated polyurethane to the elastic polyurethane is 1:(7.5-8.5).

[0013] By adopting the above technical solution, this application further specifies the ratio of hydrophobic fluorinated polyurethane to elastic polyurethane, thereby further improving the waterproof performance of the water vapor barrier layer.

[0014] In one specific implementation, the raw materials of the insulation layer include the following components in parts by weight: 40-50 parts of TPU hot melt adhesive powder, 10-20 parts of glass microspheres, and 1-10 parts of gelatin.

[0015] By adopting the above technical solution, TPU hot melt adhesive and gelatin have high bonding performance, which can effectively combine the water vapor barrier layer and TPU film together. The low thermal conductivity of glass microspheres results in a good insulation effect for the formed insulation layer. In addition, glass microspheres also have good hydrophobic properties. With the addition of gelatin, the insulation layer can also have a certain degree of waterproof performance.

[0016] Secondly, the preparation process of a waterproof TPU film provided in this application adopts the following technical solution:

[0017] A process for preparing a waterproof TPU film includes the following steps:

[0018] Membrane preparation: Elastic polyurethane, hydrophobic fluorinated polyurethane, and filler are added to acetyl dimethylamine to obtain a spinning solution. Then, a water vapor barrier membrane is obtained using nano-electrospinning technology, which is the water vapor barrier layer.

[0019] Composite process: TPU hot melt adhesive powder, glass microspheres, and gelatin are stirred and mixed evenly to obtain a mixture. The mixture is heated and melted to obtain a hot melt adhesive. The hot melt adhesive is cast onto a TPU film. Then, a water vapor barrier film is laid on the hot melt adhesive and laminated with the TPU film. After the hot melt adhesive cures, it forms a heat insulation layer, thus obtaining a waterproof TPU film.

[0020] By adopting the above technical solution and using the above methods, a TPU film with good waterproof performance can be obtained.

[0021] In one specific implementation, in the film-forming step, elastic polyurethane, hydrophobic fluorinated polyurethane, and filler are added to acetyl dimethylamine to obtain a spinning solution, and then a water vapor barrier membrane is obtained at 20-30°C using nano-electrospinning technology.

[0022] In one specific implementation, during the film-forming step, the filler in the spinning solution has a weight fraction of 15-20%.

[0023] By adopting the above technical solution, this application further limits the electrospinning temperature and the amount of filler, thereby further improving the water permeability resistance of the prepared water vapor barrier membrane.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. In this application, ethanol is used as a solvent, and boron nitride is modified with dimethylvinylethoxysilane, so that boron nitride can be uniformly dispersed in the water vapor barrier layer and form a rough structure. In addition, dimethylvinylethoxysilane can couple elastic polyurethane with hydrophobic fluorinated polyurethane to form a sieve structure, which can block water vapor molecules in the gas. The hydrophobic fluorinated polyurethane can improve the hydrophobicity of the water vapor barrier layer, and the rough structure can expel the water vapor blocked on the surface, thereby giving the water vapor barrier layer water permeability resistance. The setting of the thermal insulation layer can reduce the phenomenon of water vapor in the air liquefying due to temperature difference. Therefore, the combination of thermal insulation layer and water vapor barrier layer improves the waterproof performance of TPU film.

[0026] 2. In this application, the TPU hot melt adhesive and gelatin have high bonding performance, which can effectively bond the moisture barrier layer and the TPU film together. The glass microspheres have a low thermal conductivity, resulting in a good insulation effect for the formed insulation layer. Furthermore, the glass microspheres also have good hydrophobic properties. With the addition of gelatin, the insulation layer can also have a certain degree of waterproof performance. 3. The method in this application first uses nano-electrospinning technology to prepare a moisture barrier film, then prepares a hot melt adhesive, casts the hot melt adhesive onto the TPU film, and then lays the moisture barrier film on the hot melt adhesive, combining it with the TPU film to obtain a TPU film with good waterproof performance. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] All raw materials used in the examples are commercially available. The elastic polyurethane was provided by Suzhou Spirax New Materials Co., Ltd., model number 3488; the hydrophobic fluorinated polyurethane was provided by Shanghai Xiangjin Chemical Reagent Co., Ltd.; the TPU hot melt adhesive powder was provided by Dongguan Zhangmutou Hongji Plastics Trading Co., Ltd., item number 0000; and the glass microspheres were nano-sized.

[0029] Preparation Example

[0030] Preparation Example 1

[0031] Preparation Example 1 provides a method for preparing a packing material, comprising the following steps:

[0032] Dimethylvinylethoxysilane, ethanol, and water were stirred and mixed evenly to obtain a spraying solution. Boron nitride was added to a high-speed mixer, and the spraying solution was sprayed onto the boron nitride during the stirring process. After spraying, the mixture was stirred for another 0.5 hours, and then dried at 50°C for 2 hours to obtain the filler. The weight ratio of dimethylvinylethoxysilane, ethanol, and water in the spraying solution was 5:18:2, and the weight ratio of dimethylvinylethoxysilane to boron nitride was 1:60.

[0033] Preparation Example 2

[0034] The difference between Preparation Example 2 and Preparation Example 1 is that the weight ratio of dimethylvinylethoxysilane to boron nitride is 1:65; the remaining steps are the same as in Preparation Example 1.

[0035] Preparation Example 3

[0036] The difference between Preparation Example 3 and Preparation Example 1 is that the weight ratio of dimethylvinylethoxysilane to boron nitride is 1:70; the remaining steps are the same as in Preparation Example 1.

[0037] Preparation Example 4

[0038] The difference between Preparation Example 4 and Preparation Example 1 is that the weight ratio of dimethylvinylethoxysilane to boron nitride is 1:75; the remaining steps are the same as in Preparation Example 1.

[0039] Preparation Example 5

[0040] The difference between Preparation Example 5 and Preparation Example 1 is that the weight ratio of dimethylvinylethoxysilane to boron nitride is 1:80; the remaining steps are the same as in Preparation Example 1.

[0041] Example

[0042] Example 1

[0043] Example 1 provides a process for preparing a waterproof TPU film, including the following steps:

[0044] Membrane preparation: 70 kg of elastic polyurethane, 5 kg of hydrophobic fluorinated polyurethane, and 10 kg of the filler from Preparation Example 1 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution. Then, at 20°C, a water vapor barrier membrane was obtained using nano-electrospinning technology, which is the water vapor barrier layer; wherein the weight fraction of the filler in the spinning solution was 15%.

[0045] Composite process: Mix 45kg of TPU hot melt adhesive powder, 15kg of glass microspheres and 5kg of gelatin evenly to obtain a mixture. Heat the mixture to melt it to obtain a hot melt adhesive. Cast the hot melt adhesive onto a TPU film. Then lay a water vapor barrier film on the hot melt adhesive and laminate it with the TPU film. After the hot melt adhesive cures, it forms an insulation layer, thus obtaining a waterproof TPU film.

[0046] Examples 2-5

[0047] As shown in Table 1, the main difference between Examples 2-5 and Example 1 lies in the selection of packing material.

[0048] Table 1. Selection of packing materials in Examples 2-5

[0049] sample Selection of packing material Example 1 Preparation Example 1 Example 2 Preparation Example 2 Example 3 Preparation Example 3 Example 4 Preparation Example 4 Example 5 Preparation Example 5

[0050] Example 6

[0051] The difference between Example 6 and Example 3 is that 80 kg of elastic polyurethane, 10 kg of hydrophobic fluorinated polyurethane, and 15 kg of the filler from Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps are the same as in Example 3.

[0052] Example 7

[0053] The difference between Example 7 and Example 3 is that 90 kg of elastic polyurethane, 15 kg of hydrophobic fluorinated polyurethane, and 20 kg of the filler from Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps are the same as in Example 3.

[0054] Example 8

[0055] The difference between Example 8 and Example 6 is that 70 kg of elastic polyurethane, 10 kg of hydrophobic fluorinated polyurethane, and 15 kg of the filler from Preparation Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps are the same as in Example 6.

[0056] Example 9

[0057] The difference between Example 9 and Example 6 is that 75 kg of elastic polyurethane, 10 kg of hydrophobic fluorinated polyurethane, and 15 kg of the filler from Preparation Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 6.

[0058] Example 10

[0059] The difference between Example 10 and Example 6 is that 85 kg of elastic polyurethane, 10 kg of hydrophobic fluorinated polyurethane, and 15 kg of the filler from Preparation Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 6.

[0060] Example 11

[0061] The difference between Example 11 and Example 6 is that 90 kg of elastic polyurethane, 10 kg of hydrophobic fluorinated polyurethane, and 15 kg of the filler from Preparation Example 3 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 6.

[0062] Example 12

[0063] The difference between Example 12 and Example 6 is that 65 kg of TPU hot melt adhesive powder is heated and melted to obtain hot melt adhesive; the remaining steps are the same as in Example 6.

[0064] Example 13

[0065] The difference between Example 13 and Example 6 is that the water vapor barrier membrane is obtained using nano-electrospinning technology at 25°C; the remaining steps are the same as in Example 6.

[0066] Example 14

[0067] The difference between Example 14 and Example 6 is that the water vapor barrier membrane is obtained using nano-electrospinning technology at 30°C; the remaining steps are the same as in Example 6.

[0068] Example 15

[0069] The difference between Example 15 and Example 13 is that the filler has a weight fraction of 18% in the spinning solution; the remaining steps are the same as in Example 13.

[0070] Example 6

[0071] The difference between Example 16 and Example 13 is that the filler has a weight fraction of 20% in the spinning solution; the remaining steps are the same as in Example 13.

[0072] Comparative Example

[0073] Comparative Example 1

[0074] The difference between Comparative Example 1 and Example 1 is that 70 kg of elastic polyurethane and 15 kg of hydrophobic fluorinated polyurethane were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 1.

[0075] Comparative Example 2

[0076] The difference between Comparative Example 2 and Example 1 is that 70 kg of elastic polyurethane and 15 kg of the filler from Preparation Example 1 were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 1.

[0077] Comparative Example 3

[0078] The difference between Comparative Example 3 and Example 1 is that 70 kg of elastic polyurethane, 5 kg of hydrophobic fluorinated polyurethane, and 10 kg of boron nitride were added to acetyl dimethylamine and stirred to disperse evenly to obtain a spinning solution; the remaining steps were the same as in Example 1.

[0079] Waterproof performance test: The TPU films in each example and comparative example were sent to a testing institution for testing to obtain the waterproof pressure of the film after seven days. The higher the waterproof pressure, the better the waterproof performance of the film.

[0080] Table 2 Performance test results of the thin film

[0081]

[0082]

[0083] Combining Example 1 and Comparative Examples 1-3, the film in Example 1 exhibits the best waterproof performance. This demonstrates that when preparing the water vapor barrier film, the simultaneous addition of boron nitride modified with dimethylvinylethoxysilane and hydrophobic fluorinated polyurethane to the raw materials allows the dimethylvinylethoxysilane loaded on the surface of the boron nitride to uniformly disperse the boron nitride in the water vapor barrier layer and form a rough structure. Furthermore, the dimethylvinylethoxysilane can couple the elastic polyurethane with the hydrophobic fluorinated polyurethane to form a sieve structure, blocking water vapor molecules in the gas. The hydrophobicity of the hydrophobic fluorinated polyurethane then allows the water vapor blocked by the rough structure to escape, thus improving the waterproof performance of the prepared film.

[0084] In conjunction with Examples 1-5, the films in Examples 2-4 exhibited better waterproof performance. This indicates that when using dimethylvinylethoxysilane to modify boron nitride, the preferred ratio of dimethylvinylethoxysilane to boron nitride is 1:(65-75). Dimethylvinylethoxysilane provides a better coating effect on boron nitride, thereby improving the dispersion performance of boron nitride and thus enhancing the waterproof performance of the prepared film.

[0085] Combining Examples 3, 6, and 7, the film in Example 6 exhibits the best waterproof performance. This demonstrates that when preparing a water vapor barrier film, increasing the amount of raw materials used results in a trend where the waterproof performance of the film first increases and then decreases.

[0086] Combining Examples 6 and 8-11, the films in Examples 6, 9 and 10 have good waterproof performance. It can be seen that when preparing the water vapor barrier membrane, the preferred ratio of hydrophobic fluorinated polyurethane to elastic polyurethane is 1:(7.5-8.5), which results in a water vapor barrier membrane with good waterproof performance.

[0087] Combining Examples 6 and 12, the film in Example 6 has better waterproof performance. It can be seen that when preparing hot melt adhesive, glass microspheres and gelatin are added to the raw materials at the same time. While the glass microspheres play a heat preservation role, they can also further improve the waterproof performance of the film when combined with gelatin.

[0088] Combining Examples 6, 13, and 14, the film in Example 13 exhibits the best waterproof performance. This indicates that when preparing the water vapor barrier film, increasing the electrospinning temperature results in an initial increase followed by a decrease in the waterproof performance of the water vapor barrier film.

[0089] Combining Examples 13, 15, and 16, the waterproof performance of the films in Examples 13, 15, and 16 is not significantly different. This indicates that increasing the weight fraction of filler in the spinning solution has little impact on the waterproof performance of the resulting water vapor barrier film.

[0090] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A waterproof TPU film, comprising a TPU film, characterized in that: A moisture barrier layer is provided on the TPU film, and a thermal insulation layer is provided between the moisture barrier layer and the TPU film. The raw materials of the moisture barrier layer include the following components in parts by weight: 70-90 parts of elastic polyurethane, 5-15 parts of hydrophobic fluorinated polyurethane, and 10-20 parts of filler. The raw materials of the filler include: boron nitride, ethanol, and dimethylvinylethoxysilane. The preparation method of the filler includes the following steps: stirring and mixing dimethylvinylethoxysilane, ethanol, and water evenly to obtain a spraying liquid; stirring boron nitride, and during the stirring process, spraying the spraying liquid onto the boron nitride, and drying to obtain the filler. The raw materials of the thermal insulation layer include the following components in parts by weight: 40-50 parts of TPU hot melt adhesive powder, 10-20 parts of glass microspheres, and 1-10 parts of gelatin.

2. The waterproof TPU film according to claim 1, characterized in that: The weight ratio of the dimethylvinylethoxysilane to the boron nitride is 1:(65-75).

3. The waterproof TPU film according to claim 1, characterized in that: The weight ratio of the hydrophobic fluorinated polyurethane to the elastic polyurethane is 1:(7.5-8.5).

4. A process for preparing a waterproof TPU film as described in any one of claims 1-3, characterized in that: Includes the following steps: Membrane preparation: Elastic polyurethane, hydrophobic fluorinated polyurethane, and filler are added to acetyl dimethylamine to obtain a spinning solution. Then, a water vapor barrier membrane is obtained using nano-electrospinning technology, which is the water vapor barrier layer. Composite process: TPU hot melt adhesive powder, glass microspheres, and gelatin are stirred and mixed evenly to obtain a mixture. The mixture is heated and melted to obtain a hot melt adhesive. The hot melt adhesive is cast onto a TPU film. Then, a water vapor barrier film is laid on the hot melt adhesive and laminated with the TPU film. After the hot melt adhesive cures, it forms a heat insulation layer, thus obtaining a waterproof TPU film.

5. The preparation process of a waterproof TPU film according to claim 4, characterized in that: In the film-forming step, elastic polyurethane, hydrophobic fluorinated polyurethane, and filler are added to acetyl dimethylamine to obtain a spinning solution, and then a water vapor barrier membrane is obtained at 20-30°C using nano-electrospinning technology.

6. The preparation process of a waterproof TPU film according to claim 4, characterized in that: In the film-forming step, the filler has a weight fraction of 15-20% in the spinning solution.

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