Light conversion master batch preparation method and light conversion agricultural film prepared from light conversion master batch

Abstract

The invention discloses a light conversion master batch, a preparation method thereof and a light conversion agricultural film prepared from the light conversion master batch, and belongs to the technical field of agricultural films. The light conversion master batch comprises the following materials: a down-conversion light conversion agent, an organic fluorescent dye and a polymer material, and the mass ratio of the down-conversion light conversion agent to the organic fluorescent dye to the polymer material is (0.001-0.1): (0.001-0.1): 1. The light conversion agricultural film provided by the invention is prepared by using the light conversion master batch added with the light conversion agent and the organic fluorescent dye, the adopted light conversion agent and organic fluorescent molecules can realize conversion from ultraviolet light to red and blue light, and the combination of the red and blue light can provide a key spectrum required by plant photosynthesis; the balanced red and blue light proportion can meet the requirements of plants in different growth stages, comprehensive growth of the plants is promoted, and compared with an existing light conversion agent, the cost of a light conversion agricultural film is reduced. The adopted organic fluorescent molecules have good compatibility with a polymer material, do not need additional modification treatment, and can be directly doped into the polymer material to prepare a uniform light conversion agricultural film.

Description

Technical Field

[0001] This invention belongs to the field of agricultural film technology, specifically relating to a light-converting masterbatch, its preparation method, and a light-converting agricultural film prepared using the light-converting masterbatch. Background Technology

[0002] Plant photosynthesis primarily occurs in the blue and red light bands, and the combination of red and blue light provides the key spectrum for photosynthesis. A balanced ratio of red and blue light can meet the needs of plants at different growth stages, thereby promoting overall plant growth. In modern agriculture, agricultural films, especially light-converting films, play a crucial role. Light-converting films can alter the distribution of light in the crop growth environment by reflecting and absorbing different wavelengths of sunlight. In particular, by absorbing harmful short-wavelength rays and converting them into blue or red light, they can significantly improve the photosynthetic efficiency and growth rate of crops. The key to preparing light-converting films lies in the use of light-converting agents.

[0003] Existing light-converting agricultural films are mainly prepared by adding inorganic phosphors or rare-earth element-based light-converting agents to polymer materials. While inorganic phosphors can absorb ultraviolet or blue light from sunlight and convert it into red or far-red light, they are expensive and have complex preparation processes, hindering industrial production. Rare-earth element-based light-converting agents, although cheaper, are prone to hydrolysis and have poor weather resistance, which reduces the performance of the light-converting agricultural film with long-term use. Furthermore, existing methods for preparing inorganic light-converting agricultural films involve directly incorporating the inorganic light-converting agent into the polymer material, requiring additional modification treatment, increasing the complexity of the preparation process, and also hindering industrial production. Summary of the Invention

[0004] To address the above problems, this invention proposes a composite light-converting masterbatch using down-conversion agents and organic fluorescent dyes as light-converting additives. By combining down-conversion agents and fluorescent molecules in different proportions, ultraviolet light can be simultaneously converted to blue and red light. Furthermore, by adjusting the proportion of fluorescent molecules, a balanced red and blue light can be obtained to meet the needs of plants at different growth stages. This masterbatch is inexpensive, and its preparation method is simple and easy to operate, making it suitable for industrial production. This solution solves the problems of easy hydrolysis and poor weather resistance of rare earth element light-converting agents in the preparation of existing light-converting agricultural films. The organic fluorescent molecules used have good compatibility with polymer materials and can be directly incorporated into polymer materials to obtain uniform light-converting agricultural films, avoiding the additional modification treatment of inorganic light-converting agents, simplifying the preparation process, and facilitating industrial production.

[0005] A composite light-conversion masterbatch, by weight, comprises the following components:

[0006] Down-conversion light-converting agent: 0.001-0.1 parts;

[0007] Organic fluorescent dye: 0.001-0.1 parts;

[0008] Polymer carrier: 1 part.

[0009] The downconversion light-converting agent is selected from organic compounds that have the ability to absorb ultraviolet light and convert it into blue light emission, preferably selected from one or more of the following types: stilbene type, coumarin type, pyrazoline type, benzo[a]oxazine type, phthalimide type, triazine aminostilbene type, benzo[a]oxazine type, and stilbene-triazole type.

[0010] The downconversion brightener is specifically selected from one or more of CI fluorescent whitening agent 85, CI fluorescent whitening agent 52, CI fluorescent whitening agent 54, CI fluorescent whitening agent 135, CI fluorescent whitening agent 162, CI fluorescent whitening agent 71, and CI fluorescent whitening agent 393.

[0011] The organic fluorescent dye is selected from organic dyes that have the ability to convert ultraviolet light or short-wave visible light into red light emission, specifically selected from one or more of Fluorescent Red H5B, Solvent Red 197, Solvent Red 149, Fluorescent Red HFG, Perylene Red 630, and Fluorescent Red 195.

[0012] The polymer carrier is a thermoplastic polymer selected from one or more of polyester, polyolefin, and olefin-vinyl acetate copolymer; preferably selected from one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.

[0013] The method for preparing a composite light-conversion masterbatch includes the following steps:

[0014] The downconversion agent, organic fluorescent dye and polymer carrier are added to a high-speed mixer in proportion to mix and obtain a uniformly mixed premix.

[0015] The premixed material is added to a twin-screw extruder, and after melting and extrusion, a strip polymer is obtained;

[0016] The strip polymer is pelletized to obtain composite optical conversion masterbatch.

[0017] In step (1), the speed of the high-speed mixer is 500-1000 rpm, and the mixing time is 3-20 min;

[0018] In step (2), the die temperature of the twin-screw extruder is 180-280℃ and the screw speed is 200-350rpm;

[0019] In step (3), the rotation speed of the pelletizer is 400-800 rpm.

[0020] This also includes controlling the amount of downconversion agent and organic fluorescent dye added during the mixing process to ensure that the ratio of red to blue light in the resulting film reaches a preset value, which is calculated through the following steps:

[0021]

[0022] In the formula, γ represents the red and blue light intensities of the transmitted light from the thin film, and k1, k2, k3, and k4 are the fitting parameters obtained from the experimental data; C B C R These are the proportions of downconversion light-converting agent and organic fluorescent dye added to the thin film, respectively. and These refer to the integrated intensity of the emitted spectrum in the blue and red light bands, respectively, of a blank substrate film without any light-converting agent or fluorescent dye.

[0023] The blue light band is 400-480nm, and the red light band is 600-680nm.

[0024] A light-converting agricultural film is prepared by mixing the aforementioned composite light-converting masterbatch with a film matrix material and then forming it by blown film molding process; wherein the mass percentage of the composite light-converting masterbatch is 1%-10%, and the mass percentage of the film matrix material is 90%-99%.

[0025] The conditions for the blown film forming process are as follows: mixing temperature is 100-200℃, blown film machine barrel temperature is 150-260℃, die head temperature is 160-260℃, connector temperature is 160-260℃, and screw rotation frequency is 8.0-20.0Hz.

[0026] The beneficial effects of this invention are:

[0027] 1) The core advantage of this invention lies in achieving bidirectional synergistic conversion of ultraviolet light into red and blue light. The synergistic mechanism is as follows: the downconversion agent in the formula can capture short-wavelength ultraviolet energy that is harmful to plants and convert it into blue light emission, while the organic fluorescent dye converts ultraviolet light or part of high-energy visible light into red light emission through specific molecular orbital energy level transitions. Through this synergistic effect, the agricultural film can redistribute components in the solar spectrum that are not utilized by plants or are even harmful, converting them into a combination of red and blue light that highly matches the absorption peak of plant chlorophyll.

[0028] 2) This mechanism not only significantly improves the intensity of physiologically effective radiation, but also precisely balances the distribution of red and blue light by adjusting the ratio of downconversion light-converting agent to organic fluorescent dye, thereby meeting the specific spectral requirements of different crops or different growth stages of the same crop, and effectively promoting the overall growth and photosynthetic efficiency of plants.

[0029] 3) In terms of materials and processes, the organic fluorescent molecules and polymer materials used in this invention have excellent natural compatibility and can achieve uniform dispersion at the molecular level directly during melt extrusion without the need for additional complex surface modification treatment. This greatly simplifies the production process of masterbatch and agricultural film, significantly reduces equipment requirements and process difficulty, and is very suitable for large-scale industrial production.

[0030] 4) In terms of cost and durability, compared to traditional inorganic phosphors which are expensive and have complex preparation processes, the organic light conversion system selected in this invention is low-cost, significantly enhancing the product's market competitiveness. Simultaneously, this system effectively solves the problems of easy hydrolysis and poor weather resistance of traditional rare-earth light conversion agents, ensuring that the agricultural film maintains stable optical conversion efficiency even under long-term outdoor conditions. The resulting agricultural film has excellent transmission spectral characteristics, effectively blocking harmful ultraviolet rays while ensuring sufficient visible light transmission, thereby improving the lighting environment inside the greenhouse, helping to increase crop yield and quality, and reducing the consumption of pesticides and fertilizers. Attached Figure Description

[0031] Figure 1 This is the transmission spectrum of the light-converting agricultural film prepared in Example 1.

[0032] Figure 2 This is the absorption spectrum of the light-converting agricultural film prepared in Example 1.

[0033] Figure 3 This is the transmission spectrum of the blank film prepared in Comparative Example 1. Detailed Implementation

[0034] The present invention aims to provide a light-converting masterbatch, its preparation method, and a light-converting agricultural film prepared using the masterbatch. Specifically, it provides a light-converting masterbatch capable of converting ultraviolet light into blue and red light, its preparation method, and a light-converting agricultural film made using the masterbatch, thereby overcoming the shortcomings of the prior art.

[0035] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0036] A composite light-converting masterbatch is characterized by comprising the following materials and mass ratio: downconversion agent: organic fluorescent red dye: polymer material = (0.001-0.1): (0.001-0.1): 1.

[0037] Furthermore, the downconversion light-converting agent is selected from one or more of the following: stilbene type, coumarin type, pyrazoline type, phthalimide type, triazine aminostilbene type, stilbene-triazole type, and benzoxazole type.

[0038] Preferably, the downconversion brightener is selected from one or more of CI fluorescent brightener 85, CI fluorescent brightener 52, CI fluorescent brightener 54, CI fluorescent brightener 135, CI fluorescent brightener 162, CI fluorescent brightener 71, and CI fluorescent brightener 393.

[0039] Preferably, the lower organic fluorescent dye is selected from one or more of Fluorescent Red H5B, Solvent Red 197, Solvent Red 149, Fluorescent Red HFG, Perylene Red 630, and Fluorescent Red 195.

[0040] Furthermore, the polymer material is selected from polyethylene, polypropylene, polyolefins, ethylene-vinyl acetate copolyester, etc.

[0041] One or more of polyvinyl chloride.

[0042] The preparation steps of the agricultural film to light conversion masterbatch of the present invention are as follows:

[0043] (1) Organic fluorescent molecules and polymer materials are added to a high-speed mixer for mixing to obtain a uniformly mixed powdered polymer powder;

[0044] (2) Add the mixed powder to a twin-screw extruder and extrude strip polymer;

[0045] (3) Add the strip polymer into the pelletizer to obtain composite red and blue light agricultural film masterbatch.

[0046] Preferably, in step (1), the high-speed mixer speed is 700-800 rpm and the mixing time is 5 min-15 min.

[0047] Preferably, in step (2), the die temperature of the twin-screw extruder is 200-270℃ and the rotation speed is 250-300rpm.

[0048] Preferably, in step (1), the pelletizer speed is 500-700 rpm.

[0049] The light-converting agricultural film prepared by the light-converting masterbatch of the present invention is prepared by the following method: weigh 1-5% light-converting masterbatch and 95%-99% film matrix material by weight percentage, mix them evenly at 100℃-200℃, add them into a blown film machine and blown film to obtain the light-converting agricultural film.

[0050] Preferably, the three-zone barrel temperature of the blown film machine is 180℃-240℃, the die head temperature is 190℃-250℃, the connector temperature is 190℃-250℃, the screw rotation frequency is 10.00Hz-18.00Hz, and the winding speed is 120rpm-200rpm. The internal mixer, forced feeder, cutter, and blown film machine used in this invention are all conventional equipment in the art.

[0051] In order to obtain thin films with different red and blue light ratios under different conditions, the ratio of the downconversion agent and the organic fluorescent dye can be adjusted. This patent constructs a method for adjusting the ratio.

[0052] Let C be the amount of downconversion agent added to the thin film. B The maximum absorption and emission wavelengths are and The amount of fluorescent dye added is C R The maximum absorption and emission wavelengths are and Define the integral intervals for blue light and red light as Λ B 400nm-480nm and Λ R Given an emission spectrum of 600nm-680nm for a blank substrate film under the same illumination conditions, let I be the emission spectrum. blank (λ), then the background blue light intensity and the background red light intensity are: Let the final integrated intensities of blue and red light of the sample film be respectively... and Therefore, the red-blue ratio is:

[0053] Considering the process of photons sequentially passing through, absorbing, undergoing Stokes shift, emitting again, and absorbing a second time on the thin film, and decomposing the final output into the integrated intensities of red and blue light in their respective wavelengths; and considering that the total output of the red light portion of the transmitted light through the thin film consists of three parts: background red light, direct excitation emission from the red dye, and cascaded conversion of red light (i.e., the blue dye first emits blue light, which is then absorbed by the red dye and converted into red light), a synergistic effect needs to be taken into account, and a product-related term C is used. B C R The blue-to-red cascade caused by secondary absorption is described. Meanwhile, the total blue light output mainly includes: background blue light, the luminescence contribution of the blue light source, and the shadowing loss of blue light by the red dye (the absorption of red dye in the blue light region will reduce the blue light output).

[0054] For a given component, according to the Beer-Lambert law, the absorption fraction can be written as A = 1 - e^(-e^(-1 / 2)). -εCL Where C is the equivalent expression for the concentration or amount of the component, L is the film thickness, and ε is the equivalent extinction coefficient. Under low concentration conditions, let x = εCL and x be sufficiently small, then e -x ≈1-x, ​​therefore 1-e -x ≈x. Furthermore, the intensity of the light emitted after absorption is proportional to the amount of absorption and can be corrected using quantum yield and the Stokes energy factor. Approximating the Stokes energy factor using peak position, we have:

[0055] Furthermore, the red light output is configured as follows:

[0056] Among them, the red light agent directly excites the luminescence term I. R,dir At low concentrations, the red light-emitting agent absorbs energy from the excitable wavelength range and emits red light, the intensity of which is approximately the same as that of C. R Proportional to η. The light source intensity, absorption cross-section, quantum yield, and thickness are related to η. R Combined into a comprehensive coefficient k1, we get: I R,dir =k1C R ;

[0057] For cascaded transformation term I R,sec Because the production volume of blue light emitting agents is related to C B It is directly proportional to the secondary absorption of this portion of blue light by the red light-emitting agent, and the absorption of this portion of blue light by C is also proportional to the C. R Proportional to C, therefore the cascaded red light term is proportional to C. B C R Proportional. Combining the relevant factors into a comprehensive coefficient k2 yields I. R,sec =k2C B C R Substituting into the red light total output formula, we get

[0058] Furthermore, the blue light output is configured as follows:

[0059] Among them, blue light luminescence item I B,flu At low concentrations, the blue light absorbing short-wavelength light and emitting blue light has an intensity approximately equal to that of C. B Proportional, if the relevant factors are combined into k4, then I B,flu =k4C B ;

[0060] For the red light agent's blue light blocking loss item I B,loss Red light-emitting agents absorb light in the blue light band, which reduces blue light output; at low concentrations, this loss is approximately equal to that of C. R Proportional. Combining the relevant factors into k3, we get I. B,loss =k3C R ;

[0061] Substituting into the Blu-ray master output formula, we get

[0062] Substituting into the definition of the red-blue ratio, we obtain a simplified prediction model:

[0063] Example 1

[0064] First, 5 grams of fluorescent whitening agent 393 (OB-1) and 5 grams of perylene red 630 were added as additives to 4 kilograms of polyethylene terephthalate (PET) powder in a high-speed mixer. The high-speed mixer was set to a speed of 800 rpm and a mixing time of 10 minutes to ensure that all components were mixed evenly and to obtain a uniformly mixed polyethylene terephthalate powder.

[0065] Next, the uniformly mixed powdered polyethylene terephthalate (PET) is added to a twin-screw extruder for extrusion molding. The melt zone temperature of the twin-screw extruder is set to 275°C, the die temperature to 250°C, and the rotation speed to 280 rpm. Under these conditions, the extruder melts the powdered PET and extrudes it into strip-shaped polymer.

[0066] The extruded polymer strips are then fed into a pelletizer for cutting. The pelletizer is set to rotate at 450 rpm, and the cutting process yields uniformly sized composite masterbatch.

[0067] Finally, the prepared composite light-converting masterbatch is added to the hopper of a blown film machine for blown film forming. The die temperature of the blown film machine is set at 270℃, the three-zone barrel temperatures are set at 200℃, 220℃, and 240℃ respectively, the die head temperature is set at 235℃, the connector temperature is set at 250℃, the screw rotation frequency is 10.00Hz, and the winding speed is 120rpm. Under these parameter controls, an agricultural film with light-converting function is produced.

[0068] The resulting light-converting agricultural film possesses excellent optical properties, effectively converting light and improving the photosynthetic efficiency of crops, thereby increasing crop yield and quality. Furthermore, this light-converting agricultural film has a long service life and good weather resistance, making it suitable for use in various climatic conditions.

[0069] In this embodiment, the amounts of light-converting agent OB-1 and perylene red 630 can be adjusted as needed to achieve different light-converting effects. Simultaneously, the amount of PET powder can also be adjusted according to actual production requirements to produce light-converting agricultural films of different thicknesses and widths. Furthermore, the equipment parameters described in this embodiment (such as temperature and rotation speed) can be appropriately adjusted according to specific production conditions and equipment models to optimize the production process and product quality.

[0070] Example 2

[0071] First, 5 grams of fluorescent whitening agent 393 (OB-1) and 5 grams of perylene red 630 were added to a high-speed mixer along with 4 kilograms of polypropylene (PP) powder. The high-speed mixer was set to 800 rpm and the mixing time was 10 minutes to ensure that all components were mixed evenly, resulting in a uniformly mixed polyethylene terephthalate powder.

[0072] Next, the uniformly mixed powdered polypropylene is added to a twin-screw extruder for extrusion molding. The melt zone temperature of the twin-screw extruder is set to 200°C, the die temperature to 190°C, and the rotation speed to 280 rpm. Under these conditions, the extruder melts the powdered polypropylene and extrudes it into strips of polymer.

[0073] The extruded polymer strips are then fed into a pelletizer for cutting. The pelletizer is set to rotate at 450 rpm, and the cutting process yields uniformly sized composite masterbatch.

[0074] Finally, the prepared composite light-converting masterbatch was added to the hopper of a blown film machine for blown film forming. The die temperature of the blown film machine was set at 210℃, the three-zone barrel temperatures were set at 160℃, 180℃, and 200℃ respectively, the die head temperature was set at 190℃, the connector temperature was set at 200℃, the screw rotation frequency was 10.00Hz, and the winding speed was 120rpm. Under these parameter controls, an agricultural film with light-converting function was produced.

[0075] The resulting light-converting agricultural film possesses excellent optical properties, effectively converting light and improving the photosynthetic efficiency of crops, thereby increasing crop yield and quality. Furthermore, this light-converting agricultural film has a long service life and good weather resistance, making it suitable for use in various climatic conditions.

[0076] In this embodiment, the amounts of light-converting agent OB-1 and perylene red 630 can be adjusted as needed to achieve different light-converting effects. Simultaneously, the amount of PP powder can also be adjusted according to actual production requirements to produce light-converting agricultural films of different thicknesses and widths. Furthermore, the equipment parameters described in this embodiment (such as temperature and rotation speed) can be appropriately adjusted according to specific production conditions and equipment models to optimize the production process and product quality.

[0077] Example 3

[0078] First, 5 grams of fluorescent whitening agent 393 (OB-1) and 5 grams of perylene red 630 were added as colorants to a high-density polyethylene (HDPE) powder along with 4 kilograms of HDPE powder. The high-density polyethylene powder was mixed at a speed of 600 rpm for 10 minutes to ensure that all components were mixed evenly and to obtain a uniformly mixed HDPE powder.

[0079] Next, the uniformly mixed powdered high-density polyethylene is added to a twin-screw extruder for extrusion molding. The melt zone temperature of the twin-screw extruder is set to 200°C, the die temperature to 190°C, and the rotation speed to 280 rpm. Under these conditions, the extruder melts the powdered high-density polyethylene and extrudes it into strips of polymer.

[0080] The extruded polymer strips are then fed into a pelletizer for cutting. The pelletizer is set to rotate at 450 rpm, and the cutting process yields uniformly sized composite masterbatch.

[0081] Finally, the prepared composite light-converting masterbatch is added to the hopper of a blown film machine for blown film forming. The die temperature of the blown film machine is set at 180℃, the three-zone barrel temperatures are set at 150℃, 165℃, and 175℃ respectively, the die head temperature is set at 160℃, the connector temperature is set at 180℃, the screw rotation frequency is 10.00Hz, and the winding speed is 120rpm. Under these parameter controls, an agricultural film with light-converting function is produced.

[0082] The resulting light-converting agricultural film possesses excellent optical properties, effectively converting light and improving the photosynthetic efficiency of crops, thereby increasing crop yield and quality. Furthermore, this light-converting agricultural film has a long service life and good weather resistance, making it suitable for use in various climatic conditions.

[0083] In this embodiment, the amounts of light-converting agent OB-1 and perylene red 630 can be adjusted as needed to achieve different light-converting effects. Simultaneously, the amount of HDPE powder can also be adjusted according to actual production requirements to produce light-converting agricultural films of different thicknesses and widths. Furthermore, the equipment parameters described in this embodiment (such as temperature and rotation speed) can be appropriately adjusted according to specific production conditions and equipment models to optimize the production process and product quality.

[0084] Comparative Example 1

[0085] Unlike Example 1, the extrusion and granulation step of the light-converting masterbatch is omitted, while the remaining steps are the same, to prepare an agricultural film without the addition of light-converting masterbatch.

[0086] The light-converting agricultural film prepared in Example 1 was subjected to ultraviolet absorption spectra in the wavelength range of 280 nm to 1400 nm using an ultraviolet spectrophotometer. The results are as follows. Figure 1 As shown in the figure, the light-converting agricultural film prepared in this embodiment of the invention exhibits strong absorption in the short-wave ultraviolet region, with a maximum absorption peak at a wavelength of 332 nm. The light-converting agricultural film prepared in Example 1 displays a fluorescent red color under sunlight. The blank agricultural film of Comparative Example 1, however, is colorless. There is a significant color difference between the two. Figure 1 , Figure 2 and Figure 3Comparative analysis showed that the transmittance of the light-converting agricultural film of the present invention was significantly reduced in the ultraviolet light region. This phenomenon is due to the absorption of ultraviolet light by the organic fluorescent molecules in the light-converting agricultural film. In the visible light region, the transmittance of the light-converting agricultural film of the present invention, due to the addition of organic fluorescent molecules, was not significantly different from that of the blank film. This indicates that the addition of organic fluorescent molecules does not affect the visible light transmittance of the light-converting agricultural film.

[0087] The light-converting agricultural film prepared in Example 1 was used as the test sample, and the blank agricultural film without light-converting masterbatch prepared in Comparative Example 1 was used as the control sample. The thickness of the test sample and the control sample was kept consistent or as close as possible. A stable light source was fixed on the test platform, so that the beam perpendicularly illuminated the sample test position, and the geometric position from the light source to the sample and from the sample to the acquisition end was kept constant. An integrating sphere coupled fiber optic spectrometer was used at the acquisition end to collect the composite emission spectrum of the transmitted light, scattered light, and fluorescent emission light of the film. The spectra of the control sample and the test sample were measured sequentially under the same parameter conditions. The control sample was placed at the entrance of the integrating sphere, and the emission spectrum under the conditions of the control sample was recorded as I. blank (λ); then the sample to be tested was placed in the same position, and the emission spectrum under the conditions of the sample to be tested was recorded, denoted as I. sam (λ). Using the blue light band of 400nm to 480nm and the red light band of 600nm to 680nm as the integration intervals, the above spectra are integrated and calculated respectively.

[0088] The red-to-blue ratio of the emitted light after conversion is calculated using the following formula:

[0089]

[0090] in, It is the total intensity of emitted blue light. It is the total intensity of emitted red light. The γ value of the sample in Example 1 is 1.7.

[0091] The light-converting agricultural film of this invention partially absorbs harmful ultraviolet light through organic fluorescent molecules. Simultaneously, it transmits only beneficial blue light, achieving a light-converting effect. This light-converting action helps improve the light conditions for crops and fully utilize sunlight. In this way, the use of pesticides and fertilizers can be reduced, leading to increased crop yields.

[0092] This invention further investigated the ratio of red to blue light in the obtained thin film based on the addition amounts of downconversion agent and fluorescent dye. Building upon Example 1, the ratio of transmitted red to blue light was measured for different addition amounts, wherein the substrate value was measured... It is 100W·m -2 , It is 110 W·m -2After data fitting, we obtained k1 = 48492.7, K2 = 0.435851, k3 = 1.99392e-05, and k4 = 2259.28.

[0093] The measurement results and fitting data are as follows:

[0094] Fluorescent whitening agent addition amount Perylene red addition amount Red-blue ratio γ experimental value Calculated value of red-blue ratio γ Relative percentage error % 0.125％ 0.125％ 1.70 1.659 2.41％ 0.050％ 0.050％ 1.30 1.327 2.08％ 0.125％ 0.050％ 1.27 1.306 2.83％ 0.125％ 0.250％ 2.20 2.249 2.23％ 0.050％ 0.125％ 1.78 1.687 5.22％ 0.250％ 0.125％ 1.68 1.615 3.87％ 0.250％ 0.250％ 2.15 2.189 1.81％

[0095] The experimental values ​​were re-verified under different addition amounts, and the results are compared below:

[0096] Fluorescent whitening agent addition amount Perylene red addition amount Red-blue ratio γ experimental value Calculated value of red-blue ratio γ Relative percentage error % 0.300％ 0.200％ 1.83 1.9385 5.93％ 0.175％ 0.175％ 1.92 1.8745 2.37％ 0.200％ 0.300％ 2.31 2.4443 5.81％

[0097] As can be seen from the table above, the method of this patent can effectively calculate and predict the red-blue light ratio of the obtained film based on the amount of downconversion agent and fluorescent dye added, and can be applied to the industrial control of film performance.

Claims

1. A composite light-conversion masterbatch, characterized in that, By weight, it includes the following components: downconversion agent: 0.001-0.1 parts; organic fluorescent dye: 0.001-0.1 parts; polymer carrier: 1 part.

2. The composite light-conversion masterbatch according to claim 1, characterized in that, The downconversion light-converting agent is selected from organic compounds that have the ability to absorb ultraviolet light and convert it into blue light emission, preferably selected from one or more of the following types: stilbene type, coumarin type, pyrazoline type, benzo[a]oxazine type, phthalimide type, triazine aminostilbene type, benzo[a]oxazine type, and stilbene-triazole type.

3. The composite light-converting masterbatch according to claim 2, characterized in that, The downconversion brightener is specifically selected from one or more of CI fluorescent whitening agent 85, CI fluorescent whitening agent 52, CI fluorescent whitening agent 54, CI fluorescent whitening agent 135, CI fluorescent whitening agent 162, CI fluorescent whitening agent 71, and CI fluorescent whitening agent 393. The organic fluorescent dye is selected from organic dyes that have the ability to convert ultraviolet light or short-wave visible light into red light emission, specifically selected from one or more of Fluorescent Red H5B, Solvent Red 197, Solvent Red 149, Fluorescent Red HFG, Perylene Red 630, and Fluorescent Red 195.

4. The composite light-conversion masterbatch according to claim 1, characterized in that, The polymer carrier is a thermoplastic polymer selected from one or more of polyester, polyolefin, and olefin-vinyl acetate copolymer; preferably selected from one or more of polyethylene terephthalate, polybutylene terephthalate, polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.

5. A method for preparing a composite light-converting masterbatch according to any one of claims 1 to 4, characterized in that, Includes the following steps: The downconversion agent, organic fluorescent dye and polymer carrier are added to a high-speed mixer in proportion to mix and obtain a uniformly mixed premix. The premixed material is added to a twin-screw extruder, and after melting and extrusion, a strip polymer is obtained; The strip polymer is pelletized to obtain composite optical conversion masterbatch.

6. The preparation method according to claim 5, characterized in that, In step (1), the speed of the high-speed mixer is 500-1000 rpm, and the mixing time is 3-20 min; In step (2), the die temperature of the twin-screw extruder is 180-280℃ and the screw speed is 200-350rpm; In step (3), the rotation speed of the pelletizer is 400-800 rpm.

7. The preparation method according to claim 5, characterized in that, This also includes controlling the amount of downconversion agent and organic fluorescent dye added during the mixing process to ensure that the ratio of red to blue light in the resulting film reaches a preset value, which is calculated through the following steps: In the formula, γ represents the red and blue light intensities of the transmitted light from the thin film, and k1, k2, k3, and k4 are the fitting parameters obtained from the experimental data; C B C R These are the proportions of downconversion light-converting agent and organic fluorescent dye added to the thin film, respectively. and These refer to the integrated intensity of the emitted spectrum in the blue and red light bands, respectively, of a blank substrate film without any light-converting agent or fluorescent dye.

8. The preparation method according to claim 7, characterized in that, The blue light band is 400-480nm, and the red light band is 600-680nm.

9. A light-converting agricultural film, characterized in that, The composite light-converting masterbatch according to any one of claims 1-5 is mixed with a thin film matrix material and then processed by blown film forming process; wherein the mass percentage of the composite light-converting masterbatch is 1%-10%, and the mass percentage of the thin film matrix material is 90%-99%.

10. The light-converting agricultural film according to claim 9, characterized in that, The conditions for the blown film forming process are as follows: mixing temperature is 100-200℃, blown film machine barrel temperature is 150-260℃, die head temperature is 160-260℃, connector temperature is 160-260℃, and screw rotation frequency is 8.0-20.0Hz.

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