Agricultural film with improved light quality and increased temperature and preparation method thereof

Abstract

The invention relates to the technical field of functional agricultural films, and specifically discloses an agricultural film with improved light quality and temperature increase and a preparation method thereof. The agricultural film comprises the following raw materials: terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol, a fluorescent composite material, a catalyst and an auxiliary agent. The preparation method comprises the following steps: uniformly mixing terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst, and then, under the protection of an inert gas, performing an esterification reaction for 3-5 hours, heating the mixture for a polycondensation reaction for 1-3 hours, and cooling the mixture to obtain a polyester material. The polyester material, the fluorescent composite material and the auxiliary agent are uniformly mixed, extruded into granules, and then film-blowing is performed using a film blowing machine. The agricultural film prepared by the invention has low hygroscopicity, high light transmittance, good processing performance, and excellent rigidity, heat resistance, flexibility, impact resistance and light conversion effect.

Description

Technical Field

[0001] The present invention relates to the technical field of functional agricultural films, and more specifically, to an agricultural film with improved light quality and increased temperature and a preparation method thereof. Background Art

[0002] As a major agricultural producer, my country plays an irreplaceable role in modern agriculture. The application of agricultural films not only increases the yield of crops, but also improves agricultural production efficiency and economic benefits. In recent years, the promotion and use of functional agricultural films, especially in greenhouses, has played a significant role in increasing crop yields, increasing income, early maturity, and improving quality.

[0003] The spectral component of solar radiation that is effective for plant photosynthesis is called photosynthetically active radiation (PAR), with a wavelength range of 380-710nm, of which the red-orange light with a wavelength of 610-710nm (peak at 660nm) and the blue-violet light with a wavelength of 400-510nm (peak at 450nm) are the absorption peak areas. Red-orange light is the main excitation light in plant photosynthesis, plays an important role in plant photosynthesis, growth and flowering, and can promote plant growth. Blue-violet light, as a key wavelength in plant photosynthesis, promotes the growth of plant seedlings, leaf growth and flowering. These two bands are called "light fertilizer" for plants.

[0004] The light-converting agricultural film uses the sunlight required for photosynthesis of crops as its energy source, and converts the ultraviolet light in the sunlight that has an adverse effect on the growth of crops into red-orange light and blue-violet light that are most suitable for photosynthesis through light energy conversion materials, playing an important role in promoting the growth of crops and increasing income. The existing Chinese invention patent with announcement number CN109593222B discloses a plant light-converting film and its preparation method and application, the plant light-converting film includes a plastic film and a composite material coated on the plastic film, wherein the composite material includes resin and fluorescent powder, and the plastic film is polyvinyl chloride or polyethylene; the plant light-converting film provided by the patent can convert the green part of the light that has a smaller effect on plant growth into near-infrared light, which is beneficial to the growth of plants; but it has no conversion effect on ultraviolet light that is not conducive to plant growth, especially ultraviolet light in the B and C bands. In addition, the combination of polyvinyl chloride or polyethylene plastic film coated with composite materials will also lead to problems such as poor light stability, reduced light transmittance, and fast light conversion attenuation in the light-converting agricultural film.

[0005] With the continuous development of horticultural facilities in my country, the demand for light environment of crops has increased significantly, and the research and development of new functional agricultural films has become a hot spot in the development of the industry. In view of the shortcomings of the existing technology, the present invention proposes an agricultural film with improved light quality and temperature increase and a preparation method, which aims to improve the light conversion effect of the agricultural film while improving the light transmittance, temperature increase performance and durability, so as to meet the diversified needs of modern agriculture for functional agricultural films. Summary of the invention

[0006] In order to solve the problems that the existing light-converting agricultural films cannot efficiently convert harmful ultraviolet light in sunlight into red-orange light, blue-violet light, etc. required for plant growth, have poor light stability, reduced light transmittance, and fast light conversion attenuation, the present invention provides an agricultural film with improved light quality and warming and a preparation method.

[0007] In the first aspect, the present invention provides an agricultural film with improved light quality and increased temperature, which adopts the following technical solution:

[0008] An agricultural film with improved light quality and increased temperature comprises the following raw materials in parts by weight: 35-40 parts of terephthalic acid, 8-10 parts of adipic acid, 12-18 parts of ethylene glycol, 2-5 parts of 1,4-cyclohexanediol, 5-15 parts of fluorescent composite material, 0.5-1 part of catalyst and 1-3 parts of auxiliary agent.

[0009] Preferably, the mass ratio of terephthalic acid, adipic acid, ethylene glycol and 1,4-cyclohexanediol is 12:3:5:1.

[0010] Preferably, the agricultural film with improved light quality and increased temperature comprises the following raw materials in parts by weight: 36 parts of terephthalic acid, 9 parts of adipic acid, 15 parts of ethylene glycol, 3 parts of 1,4-cyclohexanediol, 10 parts of fluorescent composite material, 0.8 parts of catalyst, and 2 parts of auxiliary agent.

[0011] Preferably, the fluorescent composite material is prepared by the following method:

[0012] (1) Dispersing graphene oxide powder in deionized water, ultrasonically treating for 30-50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 2-3 h, collecting the supernatant by centrifugation, and dialyzing the supernatant in deionized water through a dialysis bag for 24-48 h to obtain a purified solution;

[0013] (2) adding europium oxide and manganese carbonate to a dilute acid solution and stirring until completely dissolved to obtain a mixed salt solution; adding the purified solution to the mixed salt solution and stirring for 1-2 hours, then adding itaconic acid and 2-thiophene glyoxylic acid and continuing to stir for 2-3 hours to obtain a composite solution;

[0014] (3) Add silane coupling agent to anhydrous ethanol, stir for 20-40 minutes to obtain coupling agent solution, add nano titanium dioxide to deionized water, ultrasonically treat for 20-40 minutes, add coupling agent solution, and continue ultrasonic dispersion for 1-2 hours to obtain titanium dioxide dispersion;

[0015] (4) After mixing the titanium dioxide dispersion and the composite solution, ultrasonic treatment is performed for 2-3 hours, and then freeze-drying is performed to obtain a fluorescent composite material.

[0016] Preferably, in the ultrasonic treatment process of step (1), the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8-10:100:5-10.

[0017] Preferably, in step (2), the mass ratio of europium oxide, manganese carbonate and dilute acid solution is 14-18:1:50; the mass ratio of the purified solution, mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid is 30:30-50:1-3:0.5-1.

[0018] Preferably, the silane coupling agent in step (3) is 3-aminopropyltriethoxysilane and polyethylene glycol-based cage-shaped polysilsesquioxane in a mass ratio of 7-9:1.

[0019] Preferably, in step (3), the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5-8:100:10-12.

[0020] Preferably, the catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3-5:1.

[0021] Preferably, the auxiliary agent is at least one of a flame retardant, a plasticizer and an antioxidant.

[0022] In a second aspect, the present invention provides a method for preparing an agricultural film with improved light quality and increased temperature, using the following technical solution:

[0023] A method for preparing an agricultural film with improved light quality and increased temperature, comprising the following preparation methods:

[0024] S1. After uniformly mixing terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and a catalyst by weight, under the protection of an inert gas, the reaction pressure is controlled to be 0.2-0.4 MPa, and an esterification reaction is carried out at 220-240° C. for 3-5 hours. The temperature is raised to 250-270° C., the reaction pressure is controlled to be 40-60 Pa, and a polycondensation reaction is carried out for 1-3 hours. The material is cooled and discharged to obtain a polyester material;

[0025] S2. After the polyester material, fluorescent composite material and additives are uniformly mixed, they are extruded into granules, and then film-blown using a film blowing machine to obtain the desired agricultural film with improved light quality and increased temperature.

[0026] Preferably, in step S2, the melt temperature during the film blowing process of the film blowing machine is 210-230°C, and the die head temperature is 180-200°C.

[0027] In summary, the present invention has the following beneficial effects:

[0028] The present invention uses graphene oxide with excellent optical absorption and luminescence properties, and europium oxide (EuO) with excellent luminescence performance. 3+ ) and titanium dioxide with ultraviolet scattering, absorption and photocatalytic properties were used as raw materials. The graphene oxide was dispersed by ultrasonic treatment and concentrated nitric acid to form small particles with quantum dot structure, which were then mixed with a mixed salt solution, treated with itaconic acid and 2-thiophene glyoxylic acid, and finally mixed with a titanium dioxide dispersion treated with a silane coupling agent, ultrasonicated, and freeze-dried to obtain a fluorescent composite material. Among them, manganese carbonate (Mn 4+ ) can significantly enhance the luminescent properties of the luminescent material through the luminescent activity of its manganese ions; the addition of itaconic acid and 2-thiophene glyoxylic acid can effectively disperse and stabilize the purified solution and the mixed salt solution, promote the cross-linking of the components, form a more stable composite system, and significantly improve the stability and durability of the fluorescent composite material; the fluorescent composite material prepared by the present invention has two broad excitation peaks located in the 200-380nm and 500-600nm bands respectively; wherein, when the excitation peak is in the range of 200-380nm, the emission spectrum is mainly located in the 400-5 00nm blue-violet light band and 620-720 red-orange light band; when the excitation peak is in the range of 500-600nm, the emission spectrum is mainly in the 660-760nm red light and near-infrared band; when exposed to sunlight, it can efficiently selectively absorb and convert ultraviolet and green light in the B and C bands that are harmful to plant growth, and emit blue-violet light, red-orange light and infrared light with longer wavelengths. It has good photostability and high light conversion efficiency, which not only helps to promote plant photosynthesis, but also reduces heat loss in the agricultural film and improves the insulation effect of the greenhouse.

[0029] In the present invention, titanium dioxide as an auxiliary material can absorb part of ultraviolet light, and transfer the absorbed ultraviolet light energy to graphene oxide quantum dots and europium ions through resonance energy transfer, so that they are excited and emit red-orange light and blue-violet light; in addition, titanium dioxide can reflect and scatter ultraviolet light, and the reflection and scattering effects will make the path of light waves propagating in the medium complicated, thereby slowing down the speed of light conversion attenuation, effectively solving the problem of fast light conversion attenuation of existing light conversion agricultural films, and extending the fluorescence life of the fluorescent composite material. By using 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane as a silane coupling agent to treat titanium dioxide, a chemical bond can be formed with the surface of titanium dioxide, and an active amino functional group is provided, which is conducive to the ultrasonic reaction of titanium dioxide dispersion and composite solution, thereby enhancing the dispersibility and stability of the fluorescent composite material, and improving its comprehensive fluorescence performance and mechanical properties.

[0030] The fluorescent composite material of the present invention is used for preparing agricultural films, and can also increase the strength and toughness of the agricultural films. The graphene oxide and titanium dioxide therein also have significant antioxidant, antibacterial and moisturizing properties, which can slow down the aging speed of the agricultural films, extend the service life of the agricultural films, and prevent the growth of bacteria on the surface of the agricultural films to a certain extent, giving the agricultural films antibacterial and self-cleaning functions, reducing diseases and pollution; reducing water evaporation on the surface of the agricultural films, increasing soil moisture, being beneficial to plant growth, and increasing crop yields.

[0031] The present invention selects terephthalic acid, adipic acid, ethylene glycol and 1,4-cyclohexanediol as reaction monomers, selects tetraisobutoxytitanium and calcium acetate for synergistic catalysis, and strictly controls the reaction ratio to obtain a polyester material with a regular structure and a narrow molecular weight distribution; adipic acid is added to introduce a flexible structural unit, thereby reducing the crystallinity of the polyester material, thereby enhancing the flexibility and chemical resistance of the material; the introduction of 1,4-cyclohexanediol can greatly improve the transparency of the polyester material; the obtained polyester material has good compatibility with the fluorescent composite material, and the agricultural film obtained by blending has low hygroscopicity, high light transmittance, good processing performance, and also has excellent rigidity, heat resistance, flexibility, impact resistance and light conversion effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the emission spectrum of the agricultural film prepared in Example 2 of the present invention under excitation at 200-380nm.

[0033] Figure 2 This is the emission spectrum of the agricultural film prepared in Example 2 of the present invention under 500-600nm excitation. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with examples. It should be understood that the following examples are only exemplary descriptions and explanations of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies realized based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0035] The raw materials used in the examples and comparative examples of the present invention are as follows:

[0036] Graphene oxide powder: average thickness 1-3nm, diameter 4-7μm, number of layers 2-5;

[0037] Europium oxide: content 99.9%, average particle size 50nm, specific surface area 30-50m 2 / g;

[0038] Manganese carbonate: content 99%;

[0039] Itaconic acid: content 99.8%;

[0040] 2-Thiophene glyoxylic acid: content 99%;

[0041] Nano titanium dioxide: content 99.9%, average particle size 15nm.

[0042] Preparation Examples 1-3 and Comparative Preparation Examples 1-4 provide methods for preparing fluorescent composite materials.

[0043] Preparation Example 1:

[0044] The fluorescent composite material is prepared by the following method:

[0045] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0046] (2) europium oxide and manganese carbonate were added to a dilute hydrochloric acid solution with a mass concentration of 5% in a mass ratio of 14:1:50, and stirred at a speed of 80 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 2 hours, and then itaconic acid and 2-thiophene glyoxylic acid were added and stirred for 3 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid was 30:30:1:0.5;

[0047] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 7:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0048] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0049] Preparation Example 2:

[0050] The fluorescent composite material is prepared by the following method:

[0051] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 350 W and the ultrasonic frequency to 42 kHz, ultrasonically treating at room temperature for 40 min, adding concentrated nitric acid and continuing ultrasonic treatment for 2.5 h, centrifuging at 12500 rpm for 15 min to collect the supernatant, dialyzing the supernatant in deionized water for 36 h through a dialysis bag with a molecular weight cutoff of 1200 Da to obtain a purified solution, and storing it in a sealed state at 4°C away from light for future use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 9:100:8;

[0052] (2) europium oxide and manganese carbonate were added to a dilute hydrochloric acid solution with a mass concentration of 7% in a mass ratio of 16:1:50, and stirred at a speed of 120 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 1.5 hours, and then itaconic acid and 2-thiophene glyoxylic acid were added and stirred for 2.5 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid was 30:40:2:0.8;

[0053] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:80, stir at 400 r / min for 30 min at 65°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 8:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 350 W, the ultrasonic frequency to 30 kHz, perform ultrasonic treatment at room temperature for 30 min, add the coupling agent solution, and continue ultrasonic dispersion for 1.5 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 6.5:100:11;

[0054] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 6:1, the ultrasonic power was controlled to be 350 W and the ultrasonic frequency to be 30 kHz. After ultrasonic treatment at room temperature for 2.5 h, the mixture was freeze-dried at -30 °C for 36 h to obtain a fluorescent composite material.

[0055] Preparation Example 3:

[0056] The fluorescent composite material is prepared by the following method:

[0057] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 400 W and the ultrasonic frequency to 45 kHz, ultrasonically treating at room temperature for 30 min, adding concentrated nitric acid and continuing ultrasonic treatment for 2 h, centrifuging at 15000 rpm for 10 min to collect the supernatant, dialyzing the supernatant in deionized water through a dialysis bag with a molecular weight cutoff of 1500 Da for 48 h to obtain a purified solution, and sealing and storing it at 4°C in the dark for future use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 10:100:10;

[0058] (2) europium oxide and manganese carbonate are added to a dilute hydrochloric acid solution with a mass ratio of 18:1:50, and stirred at a speed of 150 r / min at room temperature until they are completely dissolved to obtain a mixed salt solution; the purified solution is added to the mixed salt solution, stirred for 1 hour, and then itaconic acid and 2-thiophene glyoxylic acid are added and stirred for 2 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid is 30:50:3:1;

[0059] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:90, stir at 75°C at a speed of 500 r / min for 20 min to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 9:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 400 W, the ultrasonic frequency to 35 kHz, perform ultrasonic treatment at room temperature for 20 min, add the coupling agent solution, and continue ultrasonic dispersion for 1 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 8:100:12;

[0060] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 7:1, the ultrasonic power was controlled to be 400 W and the ultrasonic frequency to be 35 kHz. After ultrasonic treatment at room temperature for 2 h, the mixture was freeze-dried at -40 °C for 24 h to obtain a fluorescent composite material.

[0061] Comparative Preparation Example 1:

[0062] The fluorescent composite material is prepared by the following method:

[0063] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0064] (2) europium oxide and manganese carbonate were added to a 5% dilute hydrochloric acid solution at a mass ratio of 14:1:50, and stirred at a speed of 80 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 2 h, and then itaconic acid was added and stirred for 3 h to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, and itaconic acid was 30:30:1.5;

[0065] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 7:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0066] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0067] Comparative Preparation Example 2:

[0068] The fluorescent composite material is prepared by the following method:

[0069] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0070] (2) europium oxide and manganese carbonate were added to a dilute hydrochloric acid solution with a mass concentration of 5% in a mass ratio of 14:1:50, and stirred at a speed of 80 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 2 hours, and then 2-thiophene glyoxylic acid was added and stirred for 3 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution and the 2-thiophene glyoxylic acid was 30:30:1.5;

[0071] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 7:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0072] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0073] Comparative Preparation Example 3:

[0074] The fluorescent composite material is prepared by the following method:

[0075] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0076] (2) europium oxide and manganese carbonate were added to a dilute hydrochloric acid solution with a mass concentration of 5% in a mass ratio of 14:1:50, and stirred at a speed of 80 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 2 hours, and then itaconic acid and 2-thiophene glyoxylic acid were added and stirred for 3 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid was 30:30:1:0.5;

[0077] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0078] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0079] Comparative Preparation Example 4:

[0080] The fluorescent composite material is prepared by the following method:

[0081] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0082] (2) europium oxide and manganese carbonate were added to a dilute hydrochloric acid solution with a mass concentration of 5% in a mass ratio of 14:1:50, and stirred at a speed of 80 r / min at room temperature until completely dissolved to obtain a mixed salt solution; the purified solution was added to the mixed salt solution, stirred for 2 hours, and then itaconic acid and 2-thiophene glyoxylic acid were added and stirred for 3 hours to obtain a composite solution; wherein the mass ratio of the purified solution, the mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid was 30:30:1:0.5;

[0083] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is polyethylene glycol-cage polysilsesquioxane; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0084] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0085] Comparative Preparation Example 5:

[0086] The fluorescent composite material is prepared by the following method:

[0087] (1) Dispersing graphene oxide powder in deionized water, controlling the ultrasonic power to 300 W and the ultrasonic frequency to 38 kHz, ultrasonically treating at room temperature for 50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 3 h, centrifuging at 10000 rpm for 20 min to collect the supernatant, dialyzing the supernatant in deionized water for 24 h through a dialysis bag with a molecular weight cutoff of 1000 Da, obtaining a purified solution, and sealing and storing it at 4°C in a dark place for later use; wherein, in the ultrasonic treatment process, the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8:100:5;

[0088] (2) Add europium oxide to a 5% dilute hydrochloric acid solution at a mass ratio of 15:50, and stir at 80 r / min at room temperature until completely dissolved to obtain a europium salt solution; add the purified solution to the europium salt solution, stir and mix for 2 h, then add itaconic acid and 2-thiophene glyoxylic acid and continue stirring for 3 h to obtain a composite solution; wherein the mass ratio of the purified solution, europium salt solution, itaconic acid and 2-thiophene glyoxylic acid is 30:30:1:0.5;

[0089] (3) Add silane coupling agent to anhydrous ethanol at a mass ratio of 1:70, stir at 300 r / min for 40 min at 55°C to obtain a coupling agent solution; wherein the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane at a mass ratio of 7:1; add nano-titanium dioxide to deionized water, control the ultrasonic power to 300 W, the ultrasonic frequency to 25 kHz, perform ultrasonic treatment at room temperature for 40 min, add the coupling agent solution, and continue ultrasonic dispersion for 2 h to obtain a titanium dioxide dispersion; wherein the mass ratio of nano-titanium dioxide, deionized water, and coupling agent solution is 5:100:10;

[0090] (4) After mixing the titanium dioxide dispersion and the composite solution at a mass ratio of 5:1, the ultrasonic power was controlled to be 300 W and the ultrasonic frequency to be 25 kHz. After ultrasonic treatment at room temperature for 3 h, the mixture was freeze-dried at -20 °C for 48 h to obtain a fluorescent composite material.

[0091] Embodiments 1-3 provide an agricultural film with improved light quality and increased temperature and a preparation method thereof.

[0092] Embodiment 1:

[0093] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in Preparation Example 1, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0094] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0095] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0096] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0097] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0098] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0099] Embodiment 2:

[0100] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 36 kg of terephthalic acid, 9 kg of adipic acid, 15 kg of ethylene glycol, 3 kg of 1,4-cyclohexanediol, 10 kg of the fluorescent composite material prepared in Preparation Example 2, 0.8 kg of a catalyst, and 2 kg of an auxiliary agent;

[0101] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 4:1;

[0102] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0103] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0104] S1. Control the stirring speed to 400r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 100°C for 25min until uniform, and then control the reaction pressure to 0.3MPa under nitrogen gas protection, and carry out esterification reaction at 230°C for 4h, then increase the temperature to 260°C, control the reaction pressure to 50Pa, and carry out polycondensation reaction for 2h, and then cool and discharge the material to obtain a polyester material;

[0105] S2. Control the stirring speed to 400r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 80°C for 15 minutes until they are uniform, melt-extrude and granulate them at 160°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and increased temperature; wherein, the melting temperature of the film blowing machine during the film blowing process is 220°C, and the die head temperature is 190°C.

[0106] Embodiment 3:

[0107] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 40 kg of terephthalic acid, 10 kg of adipic acid, 18 kg of ethylene glycol, 5 kg of 1,4-cyclohexanediol, 15 kg of the fluorescent composite material prepared in Preparation Example 3, 1 kg of a catalyst, and 3 kg of an auxiliary agent;

[0108] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 5:1;

[0109] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0110] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0111] S1. Control the stirring speed to 500r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 120°C for 20min until uniform, and then control the reaction pressure to 0.4MPa under nitrogen gas protection, and carry out esterification reaction at 240°C for 3h, then increase the temperature to 270°C, control the reaction pressure to 60Pa, and carry out polycondensation reaction for 1h, and then cool and discharge the material to obtain a polyester material;

[0112] S2. Control the stirring speed to 500r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 90°C for 10 minutes until they are uniform, melt-extrude and granulate them at 170°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and increased temperature; wherein, the melting temperature of the film blowing machine during the film blowing process is 230°C, and the die head temperature is 200°C.

[0113] In order to verify the comprehensive performance of the agricultural films with improved light quality and increased temperature prepared in Examples 1-3 of the present invention, the applicant set up Comparative Examples 1-7, as follows.

[0114] Comparative Example 1:

[0115] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in comparative preparation example 1, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0116] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0117] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0118] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0119] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0120] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0121] Comparative Example 2:

[0122] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in comparative preparation example 2, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0123] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0124] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0125] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0126] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0127] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0128] Comparative Example 3:

[0129] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in comparative preparation example 3, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0130] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0131] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0132] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0133] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0134] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0135] Comparative Example 4:

[0136] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in comparative preparation example 4, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0137] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0138] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0139] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0140] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0141] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0142] Comparative Example 5:

[0143] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in comparative preparation example 5, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0144] The catalyst is tetraisobutoxytitanium and calcium acetate in a mass ratio of 3:1;

[0145] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0146] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0147] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0148] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0149] Comparative Example 6:

[0150] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in Preparation Example 1, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0151] Wherein, the catalyst is tetraisobutoxytitanium;

[0152] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0153] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0154] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0155] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0156] Comparative Example 7:

[0157] An agricultural film with improved light quality and temperature increase, comprising the following raw materials: 35 kg of terephthalic acid, 8 kg of adipic acid, 12 kg of ethylene glycol, 2 kg of 1,4-cyclohexanediol, 5 kg of the fluorescent composite material prepared in Preparation Example 1, 0.5 kg of a catalyst, and 1 kg of an auxiliary agent;

[0158] Among them, the catalyst is calcium acetate;

[0159] The additives include phosphate ester, dibutyl phthalate and antioxidant 168 in a mass ratio of 1:1:1.

[0160] A method for preparing an agricultural film with improved light quality and increased temperature comprises the following steps:

[0161] S1. Control the stirring speed to 300r / min, and mix terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and the catalyst at 80°C for 30min until uniform, and then control the reaction pressure to 0.2MPa under nitrogen gas protection, and carry out esterification reaction at 220°C for 5h, then increase the temperature to 250°C, control the reaction pressure to 40Pa, and carry out polycondensation reaction for 3h, and then cool and discharge the material to obtain a polyester material;

[0162] S2. Control the stirring speed to 300r / min, stir and mix the polyester material, fluorescent composite material and additives at a temperature of 70°C for 20min until they are uniform, melt-extrude and granulate them at 150°C through a screw machine, and then use a film blowing machine to blow the film to obtain the required agricultural film with improved light quality and warming; wherein, the melting temperature of the film blowing machine during the film blowing process is 210°C, and the die head temperature is 180°C.

[0163] Performance testing:

[0164] The comprehensive properties of the agricultural films with improved light quality and increased temperature prepared in Examples 1-3 of the present invention and Comparative Examples 1-7 were tested respectively, as follows:

[0165] Examples 1-3 and Comparative Examples 1-7 were blown into agricultural film samples with a thickness of 0.03 mm;

[0166] According to the method in the national standard GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics", the light transmittance and haze of agricultural film samples were tested respectively;

[0167] The film samples were placed in a constant temperature and humidity chamber, set at 175°C and 85% humidity, and subjected to wet heat aging for 140 hours, and then placed in a room temperature environment for recovery for 48 hours; referring to the method in GB / T 1040.1-2018 "Determination of tensile properties of plastics", the tensile strength of the agricultural film samples before and after aging was tested respectively;

[0168] The agricultural film samples were optically characterized using a fluorescence spectrometer, and the fluorescence intensity was tested before and after 12 months of use in an open-air environment. The fluorescence intensity retention rate was calculated. The test results are shown in Table 1 below.

[0169] Table 1:

[0170] .

[0171] It can be seen from the data shown in Table 1 above that the agricultural films with improved light quality and warming prepared in Examples 1-3 have high light transmittance, high haze, good warming and insulation effects in the greenhouse; high tensile strength, good moisture and heat stability, and good durability; the comprehensive performance is significantly better than that of Comparative Examples 1-7, and has broad market prospects.

[0172] Depend on Figure 1 The displayed results show that the agricultural film prepared in Example 2 of the present invention shows a wide absorption in the wavelength range of 200-380nm (peak at about 315nm), and the emission spectrum is mainly located in the blue-violet light band of 400-500nm (peak at about 458nm) and the red-orange light band of 620-720 (peak at about 660nm).

[0173] Depend on Figure 2 The displayed results show that the agricultural film prepared in Example 2 of the present invention has an emission spectrum mainly located in the red light and near-infrared bands of 660-760nm (peak at around 738nm) under excitation at 500-600nm (peak at around 540nm).

[0174] In summary, the fluorescent composite material prepared by the present invention has two broad excitation peaks respectively located in the 200-380nm and 500-600nm bands; wherein, when the excitation peak is located in the range of 200-380nm, the emission spectrum is mainly located in the 400-500nm blue-violet light band and the 620-720 red-orange light band; and when the excitation peak is located in the range of 500-600nm, the emission spectrum is mainly located in the 660-760nm red light and near-infrared bands; when irradiated by sunlight, it can efficiently selectively absorb and convert ultraviolet light and green light in the B and C bands that are harmful to plant growth, and emit blue-violet light, red-orange light and infrared light with longer wavelengths, and has good light stability and high light conversion efficiency, which not only helps to promote plant photosynthesis, but also can reduce heat loss in agricultural film and improve the insulation effect of the greenhouse.

[0175] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An agricultural film with improved light quality and increased temperature, It is characterized in that The method comprises the following raw materials in parts by weight: 35-40 parts of terephthalic acid, 8-10 parts of adipic acid, 12-18 parts of ethylene glycol, 2-5 parts of 1,4-cyclohexanediol, 5-15 parts of fluorescent composite material, 0.5-1 parts of catalyst, and 1-3 parts of auxiliary agent; The catalyst is tetraisobutoxytitanium and calcium acetate; The fluorescent composite material is prepared by the following method: (1) Dispersing graphene oxide powder in deionized water, ultrasonically treating for 30-50 min, adding concentrated nitric acid and continuing ultrasonic treatment for 2-3 h, collecting the supernatant by centrifugation, and dialyzing the supernatant in deionized water through a dialysis bag for 24-48 h to obtain a purified solution; (2) adding europium oxide and manganese carbonate to a dilute acid solution and stirring until completely dissolved to obtain a mixed salt solution; adding the purified solution to the mixed salt solution and stirring for 1-2 hours, then adding itaconic acid and 2-thiophene glyoxylic acid and continuing to stir for 2-3 hours to obtain a composite solution; (3) Add silane coupling agent to anhydrous ethanol, stir for 20-40 minutes to obtain coupling agent solution, add nano titanium dioxide to deionized water, ultrasonically treat for 20-40 minutes, add coupling agent solution, and continue ultrasonic dispersion for 1-2 hours to obtain titanium dioxide dispersion; (4) mixing the titanium dioxide dispersion and the composite solution, ultrasonically treating for 2-3 hours, and freeze-drying to obtain a fluorescent composite material; In the step (3), the silane coupling agent is 3-aminopropyltriethoxysilane and polyethylene glycol-cage polysilsesquioxane; Preparation of the agricultural film with improved light quality and increased temperature: S1. After uniformly mixing terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and a catalyst by weight, under the protection of an inert gas, the reaction pressure is controlled to be 0.2-0.4 MPa, and an esterification reaction is carried out at 220-240° C. for 3-5 hours. The temperature is raised to 250-270° C., the reaction pressure is controlled to be 40-60 Pa, and a polycondensation reaction is carried out for 1-3 hours. The material is cooled and discharged to obtain a polyester material; S2. After the polyester material, the fluorescent composite material and the additive are uniformly mixed, the mixture is extruded into granules, and then a film is blown by a film blowing machine to obtain an agricultural film with improved light quality and increased temperature.

2. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that The mass ratio of the terephthalic acid, adipic acid, ethylene glycol and 1,4-cyclohexanediol is 12:3:5:

1.

3. The agricultural film with improved light quality and increased temperature according to claim 2, It is characterized in that The invention comprises the following raw materials in parts by weight: 36 parts of terephthalic acid, 9 parts of adipic acid, 15 parts of ethylene glycol, 3 parts of 1,4-cyclohexanediol, 10 parts of fluorescent composite material, 0.8 parts of catalyst and 2 parts of auxiliary agent.

4. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that In the ultrasonic treatment process of step (1), the mass ratio of graphene oxide powder, deionized water and concentrated nitric acid is 8-10:100:5-10.

5. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that In the step (2), the mass ratio of europium oxide, manganese carbonate and dilute acid solution is 14-18:1:50; the mass ratio of the purified solution, mixed salt solution, itaconic acid and 2-thiophene glyoxylic acid is 30:30-50:1-3:0.5-1.

6. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that The mass ratio of the 3-aminopropyltriethoxysilane to the polyethylene glycol-cage polysilsesquioxane is 7-9:

1.

7. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that In the step (3), the mass ratio of nano-titanium dioxide, deionized water and coupling agent solution is 5-8:100:10-12.

8. The agricultural film with improved light quality and increased temperature according to claim 1, It is characterized in that The mass ratio of tetraisobutoxytitanium to calcium acetate is 3-5:

1.

9. A method for preparing an agricultural film with improved light quality and increased temperature as claimed in any one of claims 1 to 8, It is characterized in that The following steps are involved: S1. After uniformly mixing terephthalic acid, adipic acid, ethylene glycol, 1,4-cyclohexanediol and a catalyst by weight, under the protection of an inert gas, the reaction pressure is controlled to be 0.2-0.4 MPa, and an esterification reaction is carried out at 220-240° C. for 3-5 hours. The temperature is raised to 250-270° C., the reaction pressure is controlled to be 40-60 Pa, and a polycondensation reaction is carried out for 1-3 hours. The material is cooled and discharged to obtain a polyester material; S2. After the polyester material, the fluorescent composite material and the additive are uniformly mixed, the mixture is extruded into granules, and then a film is blown by a film blowing machine to obtain the desired agricultural film with improved light quality and increased temperature.

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