A biaxially oriented nylon light-transmitting film and its preparation method and application

Abstract

This invention provides a biaxially oriented nylon light-conversion film, its preparation method, and application. The film is obtained by simultaneously biaxially oriented a nylon / flaky nanosilica blend as a support layer and a nylon / boric acid-functionalized terbium metal-organic framework blend as a variable light-conversion layer. The film exhibits both dripping and variable light-conversion properties, converting ultraviolet light into red, orange, or blue light.

Description

Technical Field

[0001] The invention belongs to the technical field of thin films, and in particular relates to a biaxially oriented nylon light-converting film and a preparation method and application thereof. Background Art

[0002] Light is a crucial factor in regulating crop growth, influencing growth rate, yield, and quality. Ultraviolet light in sunlight is detrimental to crop growth and accelerates the aging of plastic products, so it needs to be filtered out as much as possible. Agricultural greenhouse light-conversion film can absorb or convert ultraviolet light from sunlight into red-orange or blue-violet light, which is beneficial for crop growth and promotes agricultural production. However, different crops or crops at different growth stages have different light-loving characteristics, and the light-conversion film needs to be replaced according to the type of crop and its growth period. To improve agricultural production efficiency and increase the utilization rate of greenhouse film, it is necessary to develop light-conversion film products with variable light-conversion properties, allowing users to easily and conveniently adjust the film's light-conversion properties according to the needs of crop growth. Summary of the Invention

[0003] In order to solve the problem that existing light-converting film products do not have variable light-converting properties, the present invention provides a biaxially oriented nylon light-converting film and a preparation method and application thereof.

[0004] The present invention provides a biaxially oriented nylon light-converting film, characterized in that it has a two-layer structure, with a nylon / flaky nano-silica blend as a support layer and a nylon / boric acid functionalized terbium metal organic framework material blend as a variable light-converting property layer;

[0005] Preferably, when the variable light-conversion layer is not sprayed with the gallic acid ethanol solution, the biaxially oriented nylon light-conversion film can convert 260-350nm ultraviolet light into 610-640nm red-orange light;

[0006] Preferably, after the variable light-conversion layer is sprayed with a gallic acid ethanol solution with a mass concentration of 1-5% and dried, the biaxially oriented nylon light-conversion film can convert 260-350nm ultraviolet light into 450-480nm blue light.

[0007] Preferably, the preparation method comprises the following steps:

[0008] (1) Preparation of boric acid functionalized terbium metal organic framework material: by weight, 3 to 6 parts of terbium chloride hexahydrate, 4 to 7 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 1 to 2 hours, and then reacted in a hydrothermal reactor at 150 to 170°C for 6 to 10 hours. After cooling to room temperature, the precipitate was centrifuged and separated, washed with anhydrous ethanol and dimethylformamide, and dried to obtain the boric acid functionalized terbium metal organic framework material;

[0009] (2) Biaxial stretching of nylon film: By weight, 1 to 3 parts of flaky nano-silica and 97 to 99 parts of nylon are melt-blended at 170 to 190°C and then extruded as the outer layer of the casting sheet. 0.2 to 1 parts of boric acid functionalized terbium metal organic framework material and 99 to 99.8 parts of nylon are melt-blended at 180 to 200°C and then extruded as the inner layer of the casting sheet. The casting sheet is then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature is 150 to 180°C, the transverse stretching ratio is 1.3 to 1.9, and the longitudinal stretching ratio is 1.5 to 2.3.

[0010] Preferably, the nylon is one of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 612, or a combination of several of them.

[0011] Preferably, the thickness of the flaky nano-silicon dioxide is 50 to 70 nm, and the length and width are 100 to 200 nm.

[0012] Preferably, the thickness of the support layer is 8 to 13 μm, and the thickness of the variable light conversion layer is 2 to 6 μm.

[0013] Preferably, the red-orange quantum yield of the biaxially oriented nylon light-converting film is 69-75%, the blue quantum yield is 70-73%, the tensile strength is 21-38 MPa, the elongation at break is 160-210%, the haze is 25-29%, the transmittance is 87-89%, the initial drip time is 210-270s, and the luminous intensity reduction rate after one year of outdoor exposure is 10-20%.

[0014] Preferably, the biaxially oriented nylon light-converting film is used in fruit and vegetable cultivation.

[0015] Compared with the existing technology, the present invention uses a nylon / flaky nano-silica blend as a support layer and a nylon / boric acid functionalized terbium metal organic framework material blend as a variable light conversion layer without adding auxiliary agents such as drip agents, defogging agents and anti-aging agents. Through synchronous biaxial stretching, a biaxially stretched nylon light conversion film with excellent mechanical properties and both drip and variable light conversion properties is obtained, which effectively avoids the frequent replacement of light conversion greenhouse films during agricultural production and increases crop yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the biaxially oriented nylon light-transmitting film in the embodiment;

[0017] Figure 2 is the light transmittance of the biaxially oriented nylon membrane;

[0018] Figure 3 is the light transmittance of the light-converting film without spraying gallic acid ethanol solution;

[0019] Figure 4 is the transmittance of the light conversion film after spraying gallic acid ethanol solution;

[0020] Figure 5 The effect of borate-functionalized terbium metal-organic framework materials on the dyne value of biaxially stretched nylon membranes. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the examples.

[0022] Example 1: This example provides a preparation method and application of a biaxially oriented nylon light-transmitting film, as follows:

[0023] (1) 3 parts of terbium chloride hexahydrate, 4 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 1 hour, and then reacted in a hydrothermal reactor at 170°C for 6 hours. After cooling to room temperature, the precipitate was centrifuged, washed with anhydrous ethanol and dimethylformamide, and dried to obtain a boric acid functionalized terbium metal organic framework material;

[0024] Boric acid-functionalized terbium metal-organic frameworks (MOFs) can generate red-orange light in the 610-640 nm range under ultraviolet light excitation. This light-conversion property is related to both the terbium ion and the organic ligand 3,5-dicarboxyphenylboronic acid. Furthermore, their light-conversion performance is affected by gallic acid. Similar findings have been reported in related literature, for example, the emission color of a boronic acid-functionalized europium MOF changes from red to blue after exposure to gallic acid (Pan L, Li XZ, Zhang QP, et al. A boricacid functional multi-emission metal organic frameworks-based fluorescence sensing platform for visualization of gallic acid[J]. Chemical Engineering Journal 450 (2022) 138283.).

[0025] The boric acid structure of the boric acid functionalized terbium metal organic framework material is polar. Adding it to the nylon film can increase the surface dyne value of the nylon film (see Figure 5 ), promoting the sliding or spreading of water droplets on the nylon film surface, achieving drip and fog removal functions. Ultraviolet rays are the main cause of nylon film aging. The light-converting film of this invention can convert ultraviolet rays into red, orange, or blue light, reducing the impact of ultraviolet rays on nylon molecular chains.

[0026] (2) One part of flaky nano-silica with a thickness of 50 nm and a length and width of 100 nm and 99 parts of nylon 66 were melt-blended at 180°C and extruded as the outer layer of the casting sheet. 0.2 parts of boric acid functionalized terbium metal organic framework material and 99.8 parts of nylon 66 were melt-blended at 200°C and extruded as the inner layer of the casting sheet. The casting sheet was then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature was 160°C, the transverse stretching ratio was 1.3, and the longitudinal stretching ratio was 1.5.

[0027] The biaxially oriented nylon light-converting film has an 8μm support layer thickness and a 6μm variable light-converting layer thickness. It has a tensile strength of 21MPa, an elongation at break of 190%, a haze of 28%, a transmittance of 88%, and an initial drop time of 252s. After one year of outdoor exposure, the red-orange luminescence intensity decreased by 20%, and the blue luminescence intensity decreased by 18%. When the variable light-converting layer of the biaxially oriented nylon light-converting film was not sprayed with a gallic acid-ethanol solution, irradiation with 260nm ultraviolet light produced 632nm red-orange light with a quantum yield of 72%. When the variable light-converting layer was sprayed with a 3% gallic acid-ethanol solution and dried, irradiation with 260nm ultraviolet light produced 459nm blue light with a quantum yield of 71%. Using the biaxially oriented nylon light-converting film without the gallic acid-ethanol solution in the variable light-converting layer increased cucumber yield by 35%.

[0028] Example 2: This example provides a preparation method and application of a biaxially oriented nylon light-transmitting film, as follows:

[0029] (1) 6 parts of terbium chloride hexahydrate, 7 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 2 hours, and then reacted in a hydrothermal reactor at 150°C for 10 hours. After cooling to room temperature, the precipitate was centrifuged, washed with anhydrous ethanol and dimethylformamide, and dried to obtain a boric acid functionalized terbium metal organic framework material;

[0030] (2) 3 parts of flaky nano-silica with a thickness of 60 nm and a length and width of 180 nm and 97 parts of nylon 12 were melt-blended at 170°C and extruded as the outer layer of the casting sheet, and 0.8 parts of boric acid functionalized terbium metal organic framework material and 99.2 parts of nylon 12 were melt-blended at 180°C and extruded as the inner layer of the casting sheet. The casting sheet was then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature was 180°C, the transverse stretching ratio was 1.9, and the longitudinal stretching ratio was 2.3.

[0031] The biaxially oriented nylon light-converting film has a support layer thickness of 10 μm and a variable light-converting layer thickness of 4 μm. It exhibits a tensile strength of 29 MPa, an elongation at break of 160%, a haze of 26%, a transmittance of 87%, and an initial drop time of 268 seconds. After one year of outdoor exposure, the red-orange luminescence intensity decreases by 15%, and the blue luminescence intensity decreases by 12%. When the variable light-converting layer of the biaxially oriented nylon light-converting film is not sprayed with a gallic acid-ethanol solution, irradiation with 315 nm ultraviolet light produces 610 nm red-orange light with a quantum yield of 69%. When the variable light-converting layer is sprayed with a 5% gallic acid-ethanol solution and dried, irradiation with 315 nm ultraviolet light produces 472 nm blue light with a quantum yield of 70%. Using biaxially oriented nylon light-converting film with a 5% gallic acid-ethanol solution as the variable light-converting layer increases strawberry yield by 12% in greenhouses.

[0032] Example 3: This example provides a preparation method and application of a biaxially oriented nylon light-transmitting film, as follows:

[0033] (1) 5 parts of terbium chloride hexahydrate, 6 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 1.5 hours, and then reacted in a hydrothermal reactor at 160°C for 8 hours. After cooling to room temperature, the precipitate was centrifuged, washed with anhydrous ethanol and dimethylformamide, and dried to obtain a boric acid functionalized terbium metal organic framework material;

[0034] (2) 2 parts of flaky nano-silica with a thickness of 70 nm and a length and width of 200 nm, 38 parts of nylon 6 and 60 parts of nylon 610 were melt-blended at 190°C and extruded as the outer layer of the casting sheet. 1 part of boric acid functionalized terbium metal organic framework material, 65 parts of nylon 66 and 34 parts of nylon 12 were melt-blended at 190°C and extruded as the inner layer of the casting sheet. The casting sheet was then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature was 150°C, the transverse stretching ratio was 1.5, and the longitudinal stretching ratio was 2.1.

[0035] The biaxially oriented nylon light-converting film has a support layer thickness of 13 μm and a variable light-converting layer thickness of 2 μm. It has a tensile strength of 38 MPa, an elongation at break of 210%, a haze of 25%, a transmittance of 89%, and an initial drop time of 213 seconds. After one year of outdoor exposure, the red-orange luminescence intensity decreased by 17%, and the blue luminescence intensity decreased by 20%. When the variable light-converting layer of the biaxially oriented nylon light-converting film was not sprayed with a gallic acid-ethanol solution, irradiation with 350 nm ultraviolet light produced 628 nm red-orange light with a quantum yield of 75%. When the variable light-converting layer was sprayed with a 1% gallic acid-ethanol solution and dried, irradiation with 315 nm ultraviolet light produced 456 nm blue light with a quantum yield of 73%. The biaxially oriented nylon light-converting film whose variable light-converting layer was not sprayed with gallic acid ethanol solution was used for the cultivation of greenhouse tomatoes in the seedling stage, while the biaxially oriented nylon light-converting film whose variable light-converting layer was sprayed with 1% gallic acid ethanol solution was used for the cultivation of greenhouse tomatoes in the fruit setting and fruiting stages, which increased the tomato yield by 25%.

[0036] The transmittance of the light-converting film without spraying the gallic acid ethanol solution and the light-converting film with spraying the gallic acid ethanol solution were tested respectively, and the transmittance curve of the light-converting film without spraying the gallic acid ethanol solution was obtained as shown in FIG. Figure 3 The transmittance curve of the light-converting film sprayed with gallic acid ethanol solution is as follows: Figure 4 .

[0037] We now offer biaxially oriented nylon films without light conversion agents, such as Figure 2 ,according to Figure 2 、 Figure 3 and Figure 4 It can be found that the biaxially oriented nylon film without the addition of a light-converting agent has good transmittance in both the ultraviolet and visible light regions (the maximum transmittance is about 92%); when the gallic acid ethanol solution is not sprayed, the ultraviolet transmittance of the light-converting film is very low, and at the same time, it has a higher transmittance in the range of 610-640nm (the maximum transmittance is about 103%); when the gallic acid ethanol solution is sprayed, the ultraviolet transmittance of the light-converting film is also very low, and at the same time, it has a higher transmittance in the range of 450-480nm (the maximum transmittance is about 102%).

[0038] Example 4: This example provides a preparation method and application of a biaxially oriented nylon light-transmitting film, as follows:

[0039] (1) 4 parts of terbium chloride hexahydrate, 5 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 2 hours, and then reacted in a hydrothermal reactor at 145°C for 9 hours. After cooling to room temperature, the precipitate was centrifuged, washed with anhydrous ethanol and dimethylformamide, and dried to obtain a boric acid functionalized terbium metal organic framework material;

[0040] (2) 1.5 parts of flaky nano-silica with a thickness of 65 nm and a length and width of 110 nm and 98.5 parts of nylon 6 were melt-blended at 180°C and extruded as the outer layer of the casting sheet, and 0.6 parts of boric acid functionalized terbium metal organic framework material and 99.4 parts of nylon 12 were melt-blended at 190°C and extruded as the inner layer of the casting sheet. The casting sheet was then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature was 160°C, the transverse stretching ratio was 1.4, and the longitudinal stretching ratio was 2.1.

[0041] The biaxially oriented nylon light-converting film has a support layer thickness of 9 μm and a variable light-converting layer thickness of 5 μm. It exhibits a tensile strength of 23 MPa, an elongation at break of 170%, a haze of 27%, a transmittance of 87%, and an initial drop time of 258 seconds. After one year of outdoor exposure, the red-orange luminescence intensity decreases by 16%, and the blue luminescence intensity decreases by 10%. When the variable light-converting layer of the biaxially oriented nylon light-converting film is not sprayed with a gallic acid-ethanol solution, irradiation with 337 nm ultraviolet light produces 616 nm red-orange light with a quantum yield of 70%. When the variable light-converting layer is sprayed with a 2% gallic acid-ethanol solution and dried, irradiation with 341 nm ultraviolet light produces 472 nm blue light with a quantum yield of 71%. Using biaxially oriented nylon light-converting film with a variable light-converting layer sprayed with a 2% gallic acid-ethanol solution increases watermelon yield by 28% in greenhouse watermelon cultivation.

[0042] The above description of the embodiments is intended to facilitate understanding and use of the present invention by those skilled in the art. Those skilled in the art will readily be able to make various modifications to these embodiments and apply the general principles described herein to other embodiments without resorting to creative effort. Therefore, the present invention is not limited to the above-described embodiments. Any improvements or modifications made by those skilled in the art based on the principles of the present invention that do not depart from the scope of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A biaxially oriented nylon light-transmitting film, characterized in that: It has a two-layer structure, with a nylon / flaky nano-silica blend as the support layer and a nylon / boric acid functionalized terbium metal organic framework material blend as the variable light conversion property layer; When the variable light-conversion layer is not sprayed with the gallic acid ethanol solution, the biaxially oriented nylon light-conversion film can convert 260-350nm ultraviolet light into 610-640nm red-orange light; After the variable light-conversion layer is sprayed with a gallic acid ethanol solution with a mass concentration of 1-5% and dried, the biaxially oriented nylon light-conversion film can convert 260-350nm ultraviolet light into 450-480nm blue light; The preparation method comprises the following steps: (1) Preparation of boric acid functionalized terbium metal organic framework material: by weight, 3 to 6 parts of terbium chloride hexahydrate, 4 to 7 parts of 3,5-dicarboxyphenylboric acid, 30 parts of water and 70 parts of dimethylformamide were stirred and mixed for 1 to 2 hours, and then reacted in a hydrothermal reactor at 150 to 170°C for 6 to 10 hours. After cooling to room temperature, the precipitate was centrifuged and separated, washed with anhydrous ethanol and dimethylformamide, and dried to obtain the boric acid functionalized terbium metal organic framework material; (2) Biaxial stretching of nylon film: By weight, 1 to 3 parts of flaky nano-silica and 97 to 99 parts of nylon are melt-blended at 170 to 190°C and then extruded as the outer layer of the casting sheet. 0.2 to 1 parts of boric acid functionalized terbium metal organic framework material and 99 to 99.8 parts of nylon are melt-blended at 180 to 200°C and then extruded as the inner layer of the casting sheet. The casting sheet is then subjected to synchronous biaxial stretching to obtain a biaxially stretched nylon light-converting film. The stretching temperature is 150 to 180°C, the transverse stretching ratio is 1.3 to 1.9, and the longitudinal stretching ratio is 1.5 to 2.

3.

2. The biaxially oriented nylon light-transmitting film according to claim 1, characterized in that: The nylon is one of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 612, or a combination of several of them.

3. The biaxially oriented nylon light-transmitting film according to claim 1, characterized in that: The thickness of the flaky nano-silicon dioxide is 50-70 nm, and the length and width are 100-200 nm.

4. The biaxially oriented nylon light-transmitting film according to claim 1, characterized in that: The thickness of the support layer is 8 to 13 μm, and the thickness of the variable light conversion layer is 2 to 6 μm.

5. The biaxially oriented nylon light-converting film according to any one of claims 1 to 4, characterized in that: The red-orange quantum yield of the biaxially oriented nylon light-converting film is 69-75%, the blue quantum yield is 70-73%, the tensile strength is 21-38 MPa, the elongation at break is 160-210%, the haze is 25-29%, the transmittance is 87-89%, the initial drip time is 210-270 seconds, and the luminous intensity reduction rate after one year of outdoor exposure is 10-20%.

6. Use of the biaxially oriented nylon light-converting film according to any one of claims 1 to 4 in fruit and vegetable cultivation.

Images