Aquaculture greenhouse film based on light conversion regulation and preparation method thereof

Abstract

The application belongs to the technical field of polymer composition preparation, and particularly relates to a water product cultivation greenhouse film based on light conversion regulation and a preparation method thereof. The water product cultivation greenhouse film comprises a red-yellow light regulation layer, a blue light inhibition layer and a support layer in sequence along the sunlight irradiation direction, and the red-yellow light regulation layer comprises a nano-silicon dioxide coated rare earth light conversion agent. The preparation method comprises the following steps: S1, respectively mixing materials according to the proportions of the red-yellow light regulation layer, the blue light inhibition layer and the support layer, melt granulation, and preparing the red-yellow light regulation layer master batch, the blue light inhibition layer master batch and the support layer master batch for standby; S2, co-extrusion blow molding the red-yellow light regulation layer master batch, the blue light inhibition layer master batch and the support layer master batch to prepare the water product cultivation greenhouse film. The application incorporates the nano-silicon dioxide coated rare earth light conversion agent into the water product cultivation greenhouse film, and solves the problems of light conversion agent migration, precipitation and easy agglomeration after wet heat aging, which leads to light conversion performance attenuation.

Description

Technical Field

[0001] This invention belongs to the field of polymer composition preparation technology, specifically relating to an aquaculture greenhouse film based on light conversion regulation and its preparation method. Background Technology

[0002] Covering aquatic organisms with greenhouse film is a common environmental control method in aquaculture. It has the functions of reducing energy consumption, isolating pollution, preventing aquatic organisms from escaping, and reducing low-temperature stress on aquatic organisms. Traditional greenhouse films are mostly made of polyethylene and polyvinyl chloride, which cannot selectively filter or enhance specific wavelengths of light according to the growth stage of aquatic organisms. This can easily lead to excessive algae growth, physiological disorders of aquatic organisms, and even immunosuppression.

[0003] Aquaculture light-converting membranes are a new type of functional film made by adding light-converting agents to plastic film materials. They have the function of changing light quality, converting light that is unfriendly to farmed organisms or has low utilization (such as ultraviolet light) into light of specific wavelengths that are beneficial to the growth and health of aquatic organisms (such as blue light and red light). Currently, when light-converting agents are incorporated into plastic film materials and used for a long time, there are defects such as migration and precipitation of light-converting agents and easy aggregation after the film is aged by wet heat. This results in poor light conversion control effect and rapid decay, which shortens the service life of the film.

[0004] Chinese patent CN109320821A discloses a method for preparing a light-modulating conversion functional film for greenhouses, using Eu... 3+ Using aluminic acid, strontium hydroxide, europium chloride, and anhydrous ethanol as raw materials, the mixture is ball-milled and then dry-hydrothermally synthesized under high temperature and high pressure (245~300℃, 10~15MPa). Finally, it is calcined under argon protection at 600~800℃ to obtain upconversion fluorescent phosphorescent functional powder.

[0005] Using glycerol fatty acid esters, lanolin esters, and polypropylene glycol 400 as raw materials, the mixture is melted at 100-120℃, then acetic acid is added as a catalyst, and the reaction is carried out for 5-6 hours. Then, thermosensitive color-changing powder is added and mixed to prepare a primary product of energy storage material. Next, using upconversion fluorescent photoluminescent functional powder and polyethylene glycol 10000 as raw materials, polyethylene glycol 10000 is dissolved into a 5wt% aqueous solution, and the fluorescent photoluminescent functional powder is added and ultrasonically dispersed to prepare a primary product of dimming material. Tx-10 emulsion is added to the primary product of energy storage material for high-speed emulsification to prepare an energy storage emulsion. Then, the primary product of dimming material and butyraldehyde are added to the energy storage emulsion for high-temperature emulsification, followed by ripening and crosslinking. After centrifugation and washing three times with water, the mixture is freeze-dried at -10℃ for 48 hours to prepare the energy storage dimming material.

[0006] This patent requires hydrothermal synthesis at 10~15MPa and 245~300℃, involving multiple material preparation steps such as upconversion powder, thermosensitive color-changing powder, energy storage phase change material, and fluorescent light-gathering material. It also involves operations such as high-speed emulsification, high-temperature emulsification, and maturation crosslinking. The operation is complicated and requires specialized equipment, which is not conducive to industrial promotion in the aquaculture field where the usage is large and the cost is sensitive.

[0007] Chinese patent CN115433405A discloses a method for preparing a rare earth organic light-converting agent coated with nano-titanium dioxide. The preparation method includes: synthesizing a rare earth organic complex using europium chloride, α-thiophenecarboxyltrifluoroacetone, 10-o-phenanthroline, and acrylic acid; mixing the rare earth organic complex with tetrabutyl titanate and stirring until homogeneous to obtain a reaction system; and removing the solvent from the reaction system by vacuum distillation to obtain the rare earth organic complex coated with nano-titanium dioxide.

[0008] Nano-titanium dioxide itself can be used as a photocatalyst, and has certain light absorption and scattering effects. It is easy to scatter and emit light, which reduces the light emission efficiency. When titanium dioxide is directly used to coat rare earth organic light-converting agents, some tetrabutyl titanate will undergo homogeneous nucleation and form agglomerates, making it difficult to ensure the uniformity of coating. Summary of the Invention

[0009] The purpose of this invention is to provide a greenhouse film for aquaculture based on light conversion regulation, which solves the problem that greenhouse films made by incorporating light conversion agents into plastic film materials suffer from light conversion agent migration, precipitation, and agglomeration after humid heat aging, leading to a decline in light conversion performance during long-term use; this invention also provides a preparation method.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] The aquaculture greenhouse film based on light conversion regulation described in this invention comprises, in sequence along the direction of sunlight irradiation, a red-yellow light regulation layer, a blue light suppression layer, and a support layer; wherein the red-yellow light regulation layer includes a red-yellow light regulation layer substrate, a nano-silica-coated rare earth light conversion agent, a drip-reducing agent, a filler, a light stabilizer, an antioxidant, and a lubricant; the blue light suppression layer includes a blue light suppression layer substrate, a blue light inhibitor, a filler, a light stabilizer, a toughening agent, and a lubricant; and the support layer includes a support layer substrate, a crosslinking agent, an antioxidant, and a lubricant.

[0012] in:

[0013] Based on a total mass of 100wt% for the red and yellow light control layer, the red and yellow light control layer consists of 55~75.5wt% red and yellow light control layer substrate, 8~15.5wt% nano-silica coated rare earth light conversion agent, 1.5~3.5wt% anti-dripping agent, 9.5~16wt% filler, 1.5~3.6wt% light stabilizer, 1.2~2.8wt% antioxidant, and 2.8~3.6wt% lubricant;

[0014] Based on a total mass of 100wt% for the blue light suppression layer, the blue light suppression layer consists of 68-75wt% blue light suppression layer substrate, 10-15wt% blue light inhibitor, 5-7wt% filler, 1.5-3wt% light stabilizer, 4.5-6.5wt% toughening agent, and 1-3wt% lubricant.

[0015] Based on a total mass of 100wt%, the support layer consists of 89~94.5wt% support layer substrate, 3.3~7.2wt% crosslinking agent, 1.7~2.8wt% antioxidant and 0.5~1wt% lubricant.

[0016] In the aforementioned red and yellow light control layer, the substrate of the red and yellow light control layer is composed of 22~30.5wt% low-density polyethylene, 18~28.5wt% linear low-density polyethylene, and 15~16.5wt% ethylene-vinyl acetate copolymer; the drip-reducing agent is one of polyglycerol fatty acid ester, octylphenol polyoxyethylene ether, or glyceryl monostearate; the filler is one of nano-calcium carbonate, hydrotalcite, or wollastonite; the light stabilizer is one of UV-531, UV-326, or UV-770; the antioxidant is one of antioxidant 245, antioxidant 1010, or antioxidant 1076; and the lubricant is erucamide.

[0017] In the aforementioned blue light suppression layer, the substrate of the blue light suppression layer is low-density polyethylene, the blue light inhibitor is cerium-doped yttrium aluminum garnet, the filler is one of nano-calcium carbonate, hydrotalcite or wollastonite, the light stabilizer is one of UV-531, UV-326 or UV-770, the toughening agent is maleic anhydride-grafted polyethylene, and the lubricant is erucamide.

[0018] In the support layer, the support layer substrate is a polyolefin elastomer, the crosslinking agent is composed of 2.5~4.6wt% tert-amyl peroxide (2-ethylhexyl) carbonate and 0.8~2.6wt% triallyl isocyanurate, the antioxidant is one of antioxidant 245, antioxidant 1010 or antioxidant 1076, and the lubricant is erucamide.

[0019] The preparation process of the nano-silica coated rare earth light-converting agent includes the following steps:

[0020] (1) Prepare an aqueous ethanol solution and an ethyl orthosilicate / ethanol solution; add europium salt, samarium salt, main ligand, second ligand, block copolymer and nucleating agent to the aqueous ethanol solution, mix well, adjust pH, keep warm, and obtain a suspension for later use;

[0021] (2) Start stirring the suspension, add tetraethyl orthosilicate / ethanol solution to the suspension for hydrolysis and condensation, and after post-treatment, obtain nano-silica coated rare earth light-converting agent.

[0022] In step (1), the ethanol-water solution is prepared at a volume ratio of ethanol to water of 1:(2.5~5.5), and the tetraethyl orthosilicate / ethanol solution is prepared at a mass ratio of tetraethyl orthosilicate to ethanol of 1:(3~6); the europium salt is europium chloride hexahydrate (EuCl3·6H2O), the samarium salt is samarium chloride hexahydrate (SmCl3·6H2O), and the main ligand is 2-thiophenecarboxyltrifluoroacetone. The second ligand is o-phenanthroline, and the nucleating agent is nano-cerium dioxide. The ratio of europium salt, samarium salt, main ligand, second ligand, nucleating agent and ethanol aqueous solution is 1:(1~1.25):(3.05~3.2):(1.02~1.1):(250~350):(5500~6500), where europium salt, samarium salt, main ligand and second ligand are in mol, nucleating agent is in g, and ethanol aqueous solution is in mL.

[0023] The block copolymer is polylactic acid-polyethylene glycol-maleimide, and the mass ratio of the block copolymer, nucleating agent, and tetraethyl orthosilicate is (400~800):(250~350):3500, wherein the nucleating agent, block copolymer, and tetraethyl orthosilicate are expressed in g; the pH is adjusted to 8.2~8.4, the heat preservation temperature is 60~70℃, and the heat preservation time is 40~60min.

[0024] In step (2), when adding tetraethyl orthosilicate / ethanol solution, the stirring speed is 550~750 rpm, the stirring speed during hydrolysis and condensation is 50~75 rpm, the hydrolysis and condensation temperature is 50~60℃, the hydrolysis and condensation pH is 8.2~8.4, and the hydrolysis and condensation time is 5~8h.

[0025] The post-processing includes centrifugation to separate the precipitate, centrifugation washing of the precipitate, and vacuum drying. The centrifugation washing of the precipitate refers to alternating centrifugation washing with ethanol and water three times. The vacuum drying pressure is 0.05~0.06MPa, the vacuum drying temperature is 60~80℃, and the vacuum drying time is 8~12h.

[0026] The method for preparing aquaculture greenhouse film based on light conversion regulation according to the present invention includes the following steps:

[0027] S1. Mix the red and yellow light control layer, blue light suppression layer and support layer according to their respective proportions, and then melt granulate to obtain red and yellow light control layer masterbatch, blue light suppression layer masterbatch and support layer masterbatch for later use.

[0028] S2. The red and yellow light regulating layer masterbatch, blue light inhibiting layer masterbatch and support layer masterbatch are co-extruded and blown into film to produce aquaculture greenhouse film.

[0029] in:

[0030] In S1, the melting and granulation temperature is 170~180℃ when preparing the red and yellow light control layer masterbatch, 175~185℃ when preparing the blue light suppression layer masterbatch, and 175~185℃ when preparing the support layer masterbatch.

[0031] In S2, the co-extrusion blown film equipment used in the co-extrusion blown film process includes an extrusion system, a co-extrusion die, a blown film system, and a traction system. The extrusion system includes a red-yellow light control layer section, a blue light suppression layer section, and a support layer section. The feeding section temperature of the red-yellow light control layer section is 135~145℃, the melting section temperature is 170~180℃, and the homogenization section temperature is 185~195℃. The feeding section temperature of the blue light suppression layer section is 150~160℃, the melting section temperature is 175~185℃, and the homogenization section temperature is 185~195℃. The feeding section temperature of the support layer section is 135~145℃, the melting section temperature is 175~185℃, and the homogenization section temperature is 180~190℃.

[0032] In the co-extrusion die, the die blowing temperature is 185~195℃, and the cooling temperature at the die outlet is 25~35℃; the thickness of the aquaculture greenhouse film is 0.070~0.100mm, and the thickness ratio of the red and yellow light control layer, the blue light suppression layer, and the support layer is 1:1:1.

[0033] In the inflation system, the total inflation ratio is 2.5~3, the traction system has a traction rate of 10~15m / min, and the initial winding tension is 105~120N.

[0034] The lubricant and dispersant described in this invention can be adsorbed onto the surface of the nano-silica-coated light-converting agent, further improving its compatibility with non-polar resins such as polyethylene, making it easier to wet and disperse during melt processing, and avoiding secondary agglomeration due to uneven shear force during processing.

[0035] The beneficial effects of this invention are as follows:

[0036] Cerium dioxide, with its high specific surface area, can act as a nucleating agent, adsorbing rare earth ions and serving as a reaction site for the organic coordination of these ions. Using tetraethyl orthosilicate as a precursor, an amorphous nano-silica shell is formed on the surface of the nucleating agent and rare earth ions through hydrolysis and condensation. This shell blocks the rare earth ions from contact with external water, heat, and oxygen, mitigating the problem of agglomeration during humid and hot aging. Furthermore, the addition of cerium dioxide further reduces the probability of homogeneous nucleation during the hydrolysis and condensation of tetraethyl orthosilicate, improving the uniformity of the coating and further enhancing the barrier effect and mitigation of agglomeration during humid and hot aging. Additionally, when nano-silica and cerium dioxide are combined, due to their refractive index difference, they can act as light scatterers, effectively extending the light propagation path and improving light conversion efficiency. Meanwhile, the Ce in cerium dioxide... 4+ / Ce 3+ The redox cycle of ion pairs can quench harmful free radicals excited by ultraviolet light, preventing free radicals from attacking the light-converting agent molecules and polymer chains. This protects the light-converting center (Eu) of the light-converting agent. 3+ 、Sm 3+ ), to suppress the decay of light conversion efficiency.

[0037] The block copolymer acts as a template agent, assisting in the formation of a well-dispersed nano-silica system in an alkaline environment. Its terminal polylactic acid (PLA) segments are hydrophilic, fully extending in ethanol / water solutions to form a hydrated, flexible, spatial protective layer. This reduces CeO2 aggregation, improving the stability of the suspension and the uniformity of the final in-situ coating. Furthermore, the carbonyl groups in the PLA chains contain lone pairs of electrons, which interact with rare earth ions (Eu). 3+ / Sm 3+ The weak coordination effect can pre-enrich rare earth ions in the solution near the surface of CeO2 particles, creating conditions for subsequent in-situ coating, greatly promoting heterogeneous nucleation and inhibiting homogeneous nucleation; the two effects thus ensure that the rare earth light-converting agent in the nano-silica coated rare earth light-converting agent is not prone to premature decay of light conversion effect due to precipitation and agglomeration.

[0038] In addition, the long-chain polyethylene glycol segments of the block copolymer further restrict the aggregation of CeO2 particles and provide contact sites for tetraethyl orthosilicate, promoting the subsequent in-situ coating of tetraethyl orthosilicate and forming a more uniform nano-silica coated light-converting agent.

[0039] In the block copolymer, maleimide undergoes ring-opening hydrolysis in an alkaline environment. The hydrolyzed ammonium salt acts as an auxiliary ligand, forming a multi-component complex with rare earth ions and 2-thiophenecarboxylic acid trifluoroacetone. This provides more donor-acceptor (dipole-dipole coupling transfer mechanism) channels for electron transfer, thereby improving the light conversion efficiency of rare earth ions.

[0040] This invention employs multilayer co-extrusion, dividing the functional layers into a red-yellow light modulation layer, a blue light suppression layer, and a support layer. This ensures that each functional layer has a more specific function, guaranteeing that the performance is not affected by other components, such as the blue light suppressant cerium-doped yttrium aluminum garnet and the rare-earth light-converting agent Eu. 3+ / Sm 3+ There is competition in the blue light conversion regulation, which will affect the utilization rate of each; secondly, it makes the function more specific, without the need to add redundant components, thus reducing production costs. For example, the support layer does not have functional materials that are easily photodegraded, so there is no need to add light stabilizers. The blue light suppression layer is located in the middle and does not directly contact the external environment, so there is no need for additional antioxidants. Finally, the optimal processing temperature of each layer is precisely matched with the characteristics of each layer material, reducing the processing difficulty. For example, different functional layers have different functional requirements, so the substrates are different and the melting temperatures are also different. Detailed Implementation

[0041] The present invention will now be described and illustrated in detail with reference to the embodiments.

[0042] Example 1

[0043] 1. Preparation of rare earth light-converting agent coated with nano-silica

[0044] Weigh out 1 mol europium chloride hexahydrate, 1.25 mol samarium chloride hexahydrate, 3.1 mol 2-thiophenecarboxyltrifluoroacetone, 1.08 mol o-phenanthroline, 600 g polylactic acid-polyethylene glycol-maleimide, 300 g nano cerium dioxide, and 3500 g tetraethyl orthosilicate. Prepare 6000 mL of ethanol-water aqueous solution at a volume ratio of 1:3.5 for later use, and prepare tetraethyl orthosilicate / ethanol solution at a mass ratio of 1:5 for later use.

[0045] Europium chloride hexahydrate, samarium chloride hexahydrate, o-phenanthroline, 2-thiophenecarboxyltrifluoroacetone, polylactic acid-polyethylene glycol-maleimide, and nano-cerium dioxide were added to an ethanol aqueous solution, the pH was adjusted to 8.2~8.4, and the solution was stirred and kept at 65℃ for 40 min to obtain a stable suspension, which was then cooled to room temperature for later use.

[0046] The stirring speed was set to 550 rpm, and the tetraethyl orthosilicate / ethanol solution was added to the suspension. The stirring speed was then reduced to 50 rpm. The pH was adjusted to 8.2-8.4 with ammonia at 50°C, and the mixture was kept at this temperature for 8 hours for hydrolysis and condensation. After the hydrolysis and condensation were completed, the mixture was centrifuged, and the precipitate was collected. The precipitate was washed three times each by alternating centrifugation with ethanol and water, and then vacuum dried at 60°C and 0.05 MPa for 12 hours to obtain nano-silica-coated rare earth light-converting agent.

[0047] 2. Melt granulation

[0048] With a total weight of 100wt% for the red and yellow light-regulating layer, and using 30.5wt% low-density polyethylene, 28.5wt% linear low-density polyethylene, 16.5wt% ethylene-vinyl acetate copolymer, 8wt% nano-silica-coated rare earth light-converting agent, 1.5wt% polyglycerol fatty acid ester, 9.5wt% nano-calcium carbonate, 1.5wt% UV-531, 1.2wt% antioxidant 1076, and 2.8wt% erucamide as raw materials, the mixture was dried and placed in a twin-screw extruder for melt granulation at 175℃ to produce 25kg of red and yellow light-regulating layer masterbatch for later use.

[0049] With a total blue light suppression layer mass of 100wt%, the raw materials are 75wt% low-density polyethylene, 10wt% cerium-doped yttrium aluminum garnet, 5wt% hydrotalcite, 1.5wt% UV-531, 5.5wt% maleic anhydride-grafted polyethylene, and 3wt% erucamide. After drying, the raw materials are placed in a twin-screw extruder and melt-granulated at 185℃ to produce 25kg of blue light suppression layer masterbatch for later use.

[0050] Using 100wt% of the total mass of the support layer as raw materials, 92.5wt% of polyolefin elastomer resin, 3.5wt% of tert-amyl peroxide (2-ethylhexyl) carbonate, 1.5wt% of triallyl isocyanurate, 1.9wt% of antioxidant 1076 and 0.6wt% erucamide, the raw materials were dried and placed in a twin-screw extruder, and melt-granulated at 175℃ to produce 25kg of support layer masterbatch for later use.

[0051] 3. Preparation of greenhouse film for aquaculture

[0052] The co-extrusion blown film equipment includes an extrusion system, a co-extrusion die, a blow-up system, and a traction system. The extrusion system includes a red-yellow light control layer section, a blue light suppression layer section, and a support layer section. The red-yellow light control layer masterbatch, blue light suppression layer masterbatch, and support layer masterbatch are added to the red-yellow light control layer section, the blue light suppression layer section, and the support layer section, respectively.

[0053] The following parameters are set: For the red-yellow light control layer section, the feeding section temperature is 135℃, the melting section temperature is 170℃, and the homogenization section temperature is 185℃; for the blue light suppression layer section, the feeding section temperature is 150℃, the melting section temperature is 175℃, and the homogenization section temperature is 185℃; for the support layer section, the feeding section temperature is 135℃, the melting section temperature is 175℃, and the homogenization section temperature is 180℃. In the co-extrusion die, the die blowing temperature is 185℃, and the cooling temperature at the die exit is 30℃; the thickness is 0.090mm, and the thickness ratio of the red-yellow light control layer, blue light suppression layer, and support layer is 1:1:1. In the blow-up system, the total blow-up ratio is 2.7; in the traction system, the traction rate is 12m / min, and the initial winding tension is 115N.

[0054] The melt extruded from the red and yellow light control layer section, the blue light suppression layer section, and the support layer section converges in the die head; after blow molding and stretching, the aquaculture greenhouse film is obtained.

[0055] Example 2

[0056] 1. Preparation of rare earth light-converting agent coated with nano-silica

[0057] Weigh out 1 mol europium chloride hexahydrate, 1.2 mol samarium chloride hexahydrate, 3.2 mol 2-thiophenecarboxyltrifluoroacetone, 1.02 mol o-phenanthroline, 800 g polylactic acid-polyethylene glycol-maleimide, 350 g nano cerium dioxide, and 3500 g tetraethyl orthosilicate. Prepare 6500 mL of ethanol-water aqueous solution at a volume ratio of 1:2.5 for later use, and prepare tetraethyl orthosilicate / ethanol solution at a mass ratio of 1:3 for later use.

[0058] Europium chloride hexahydrate, samarium chloride hexahydrate, o-phenanthroline, 2-thiophenecarboxyltrifluoroacetone, polylactic acid-polyethylene glycol-maleimide, and nano-cerium dioxide were added to an ethanol aqueous solution, the pH was adjusted to 8.2~8.4, and the mixture was stirred at 60℃ and kept at that temperature for 50 min to obtain a stable suspension, which was then cooled to room temperature for later use.

[0059] The stirring speed was set to 650 rpm. Tetraethyl orthosilicate / ethanol solution was added to the suspension. The stirring speed was then reduced to 65 rpm. The pH was adjusted to 8.2-8.4 with ammonia at 60℃ and kept at this temperature for 5 hours for hydrolysis and condensation. After hydrolysis and condensation, the precipitate was separated by centrifugation and collected. The precipitate was washed three times each by alternating centrifugation with ethanol and water. The precipitate was then vacuum dried at 70℃ and 0.06 MPa for 8 hours to obtain nano-silica-coated rare earth light-converting agent.

[0060] 2. Melt granulation

[0061] With a total weight of 100wt% for the red and yellow light control layer, and using 22wt% low-density polyethylene, 18wt% linear low-density polyethylene, 15wt% ethylene-vinyl acetate copolymer, 15.5wt% nano-silica coated rare earth light conversion agent, 3.5wt% octylphenol polyoxyethylene ether, 16wt% wollastonite, 3.6wt% UV-770, 2.8wt% antioxidant 1010 and 3.6wt% erucamide as raw materials, the mixture was dried and placed in a twin-screw extruder, where it was melt-granulated at 170℃ to produce 25kg of red and yellow light control layer masterbatch for later use.

[0062] With a total blue light suppression layer mass of 100wt%, the raw materials are 68wt% low-density polyethylene, 15wt% cerium-doped yttrium aluminum garnet, 7wt% wollastonite, 3wt% UV-770, 4.5wt% maleic anhydride-grafted polyethylene, and 2.5wt% erucamide. After drying, the raw materials are placed in a twin-screw extruder and melt-granulated at 180℃ to produce 25kg of blue light suppression layer masterbatch for later use.

[0063] Using 100wt% of the total weight of the support layer as raw materials, 94.5wt% of polyolefin elastomer resin, 2.5wt% of tert-amyl peroxide (2-ethylhexyl) carbonate, 0.8wt% of triallyl isocyanurate, 1.7wt% of antioxidant 1010 and 0.5wt% erucamide, the raw materials were dried and placed in a twin-screw extruder for melt granulation at 185℃ to produce 25kg of support layer masterbatch for later use.

[0064] 3. Preparation of greenhouse film for aquaculture

[0065] The co-extrusion blown film equipment includes an extrusion system, a co-extrusion die, a blow-up system, and a traction system. The extrusion system includes a red-yellow light control layer section, a blue light suppression layer section, and a support layer section. The red-yellow light control layer masterbatch, blue light suppression layer masterbatch, and support layer masterbatch are added to the red-yellow light control layer section, the blue light suppression layer section, and the support layer section, respectively.

[0066] The following parameters are set: For the red-yellow light control layer section, the feeding section temperature is 140℃, the melting section temperature is 180℃, and the homogenization section temperature is 195℃; for the blue light suppression layer section, the feeding section temperature is 155℃, the melting section temperature is 180℃, and the homogenization section temperature is 190℃; for the support layer section, the feeding section temperature is 140℃, the melting section temperature is 180℃, and the homogenization section temperature is 185℃. In the co-extrusion die, the die blowing temperature is 190℃, and the cooling temperature at the die exit is 35℃; the thickness is 0.070mm, and the thickness ratio of the red-yellow light control layer, blue light suppression layer, and support layer is 1:1:1. In the blow-up system, the total blow-up ratio is 3; in the traction system, the traction rate is 10m / min, and the initial winding tension is 120N.

[0067] The melt extruded from the red and yellow light control layer section, the blue light suppression layer section, and the support layer section converges in the die head; after blow molding and stretching, the aquaculture greenhouse film is obtained.

[0068] Example 3

[0069] 1. Preparation of rare earth light-converting agent coated with nano-silica

[0070] Weigh out 1 mol europium chloride hexahydrate, 1 mol samarium chloride hexahydrate, 3.05 mol 2-thiophenecarboxyltrifluoroacetone, 1.1 mol o-phenanthroline, 400 g polylactic acid-polyethylene glycol-maleimide, 250 g nano cerium dioxide, and 3500 g tetraethyl orthosilicate. Prepare 5500 mL of ethanol-water aqueous solution at a volume ratio of 1:5.5 for later use, and prepare tetraethyl orthosilicate / ethanol solution at a mass ratio of 1:6 for later use.

[0071] Europium chloride hexahydrate, samarium chloride hexahydrate, o-phenanthroline, 2-thiophenecarboxyltrifluoroacetone, polylactic acid-polyethylene glycol-maleimide, and nano-cerium dioxide were added to an ethanol aqueous solution, the pH was adjusted to 8.2~8.4, and the solution was stirred and kept at 70℃ for 60 min to obtain a stable suspension, which was then cooled to room temperature for later use.

[0072] The stirring speed was set to 750 rpm. Tetraethyl orthosilicate / ethanol solution was added to the suspension. The stirring speed was then reduced to 75 rpm. The pH was adjusted to 8.2-8.4 with ammonia at 55°C and kept at this temperature for 7 hours for hydrolysis and condensation. After hydrolysis and condensation, the mixture was centrifuged and the precipitate was collected. The precipitate was washed three times each by alternating centrifugation with ethanol and water. The mixture was then vacuum dried at 80°C and 0.06 MPa for 10 hours to obtain nano-silica-coated rare earth light-converting agent.

[0073] 2. Melt granulation

[0074] With a total weight of 100wt% for the red and yellow light-regulating layer, and using 26wt% low-density polyethylene, 25wt% linear low-density polyethylene, 15.5wt% ethylene-vinyl acetate copolymer, 10wt% nano-silica-coated rare earth light-converting agent, 2.5wt% glyceryl monostearate, 14wt% hydrotalcite, 2wt% UV-326, 2wt% antioxidant 245 and 3wt% erucamide as raw materials, the mixture was dried and placed in a twin-screw extruder for melt granulation at 180℃ to produce 25kg of red and yellow light-regulating layer masterbatch for later use.

[0075] With a total blue light suppression layer mass of 100wt%, the raw materials are 72wt% low-density polyethylene, 12wt% cerium-doped yttrium aluminum garnet, 6wt% nano-calcium carbonate, 2.5wt% UV-326, 6.5wt% maleic anhydride-grafted polyethylene, and 1wt% erucamide. After drying, the raw materials are placed in a twin-screw extruder and melt-granulated at 175℃ to produce 25kg of blue light suppression layer masterbatch for later use.

[0076] Using 100wt% of the total mass of the support layer, 89wt% of polyolefin elastomer resin, 4.6wt% of tert-amyl peroxide (2-ethylhexyl) carbonate, 2.6wt% of triallyl isocyanurate, 2.8wt% of antioxidant 245, and 1wt% erucamide as raw materials, the mixture was dried and placed in a twin-screw extruder for melt granulation at 180℃ to produce 25kg of support layer masterbatch for later use.

[0077] 3. Preparation of greenhouse film for aquaculture

[0078] The co-extrusion blown film equipment includes an extrusion system, a co-extrusion die, a blow-up system, and a traction system. The extrusion system includes a red-yellow light control layer section, a blue light suppression layer section, and a support layer section. The red-yellow light control layer masterbatch, blue light suppression layer masterbatch, and support layer masterbatch are added to the red-yellow light control layer section, the blue light suppression layer section, and the support layer section, respectively.

[0079] The following parameters are set: For the red-yellow light control layer section, the feeding section temperature is 145℃, the melting section temperature is 175℃, and the homogenization section temperature is 190℃; for the blue light suppression layer section, the feeding section temperature is 160℃, the melting section temperature is 185℃, and the homogenization section temperature is 195℃; for the support layer section, the feeding section temperature is 145℃, the melting section temperature is 185℃, and the homogenization section temperature is 190℃. In the co-extrusion die, the die blowing temperature is 195℃, and the cooling temperature at the die exit is 25℃; the thickness is 0.100mm, and the thickness ratio of the red-yellow light control layer, blue light suppression layer, and support layer is 1:1:1. In the blow-up system, the total blow-up ratio is 2.5; in the traction system, the traction rate is 15m / min, and the initial winding tension is 105N.

[0080] The melt extruded from the red and yellow light control layer section, the blue light suppression layer section, and the support layer section converges in the die head; after blow molding and stretching, the aquaculture greenhouse film is obtained.

[0081] Comparative Example 1

[0082] Without adding nano-cerium dioxide, the remaining steps and raw materials used are the same as in Example 1.

[0083] Comparative Example 2

[0084] Without adding tetraethyl orthosilicate, the remaining steps and raw materials used are the same as in Example 1.

[0085] Comparative Example 3

[0086] Without adding nano-cerium dioxide and tetraethyl orthosilicate, the remaining steps and raw materials used are the same as in Example 1.

[0087] Comparative Example 4

[0088] Single-layer blending was used instead of multi-layer co-extrusion: the red and yellow light control layer masterbatch, the blue light suppression layer masterbatch, and the support layer masterbatch were mixed and melted and granulated at 180°C, and then blown into a single layer. The processing temperature was 155°C in the feeding section, 180°C in the melting section, and 190°C in the homogenization section. Other parameters, such as total thickness, blow-up ratio, traction rate, and other steps and raw materials used, were the same as in Example 1.

[0089] Comparative Example 5

[0090] Without adding block copolymers, the remaining steps and raw materials used are the same as in Example 1.

[0091] Comparative Example 6

[0092] Without adding a main ligand, the remaining steps and raw materials were the same as in Example 1. Testing revealed that the integrated area (S0) of the initial fluorescence emission peak was much smaller than that of Example 1, indicating that the conversion film did not possess practical performance characteristics.

[0093] Implementation effect evaluation

[0094] Take the mulch films prepared in Examples 1-3 and Comparative Examples 1-5, cut them into samples of 10cm×25cm, and label them as Samples 1-8 for later use.

[0095] Humid heat aging test: First, the initial tensile strength (σ0) and initial fluorescence emission peak integrated area (S0) of samples 1-8 were tested. Then, samples 1-8 were placed in a constant temperature and humidity aging chamber, with the temperature set at 38-45℃ and the ambient humidity at 85%RH. After standing for 65 days, the samples were taken out and the tensile strength (σ1) and fluorescence emission peak integrated area (S1) after the aging test were measured. Based on σ0, σ1, S0, and S1, the tensile strength retention rate and light conversion efficiency retention rate were obtained. The specific performance test data are shown in Table 1.

[0096] Light conversion efficiency retention rate = S1 / S0 × 100%, tensile strength retention rate = σ1 / σ0 × 100%.

[0097] The tensile strength test is as follows: according to the test method described in GB / T1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets", the sampling direction is longitudinal (MD) and transverse (TD), and the tensile rate is 50 mm / min.

[0098] The fluorescence emission peak integrated area was measured as follows: The fluorescence spectrometer was turned on, the excitation wavelength of the light source was set to 340~380nm, the scanning range was set to 550~800nm, the excitation slit emission slit was set to 3.5nm, and the scanning speed was 120nm / min. Then, samples 1~8 were placed in the optical path of the fluorescence spectrometer and tested. The characteristic peaks were found within the scanning range, and the characteristic peaks were integrated to obtain the fluorescence emission peak integrated area.

[0099] Table 1 Sample performance test results

[0100]

[0101] As shown in Table 1, the light conversion efficiency and mechanical properties of the present invention are not easily degraded in long-term hot and humid environments, and the service life of the light conversion greenhouse film is longer, effectively reducing the usage cost for farmers.

Claims

1. A light conversion-based water farming greenhouse film, characterized in that, The red-yellow light regulation layer, the blue light inhibition layer and the support layer are sequentially arranged along the direction of sunlight irradiation; the red-yellow light regulation layer comprises a red-yellow light regulation layer substrate, a nano-silica coated rare earth light conversion agent, a flow agent, a filler, a light stabilizer, an antioxidant and a lubricant; the blue light inhibition layer comprises a blue light inhibition layer substrate, a blue light inhibitor, a filler, a light stabilizer, a toughening agent and a lubricant; and the support layer comprises a support layer substrate, a crosslinking agent, an antioxidant and a lubricant. The blue light inhibitor is cerium-doped yttrium aluminum garnet; and the preparation process of the nano-silica coated rare earth light conversion agent comprises the following steps: (1) preparing an ethanol aqueous solution and a tetraethyl orthosilicate / ethanol solution; adding europium salt, samarium salt, a primary ligand, a secondary ligand, a block copolymer and a nucleating agent into the ethanol aqueous solution and uniformly mixing, adjusting pH, and keeping warm to obtain a suspension for standby; (2) starting stirring of the suspension, adding the tetraethyl orthosilicate / ethanol solution into the suspension for hydrolysis and condensation, and performing post-treatment to obtain the nano-silica coated rare earth light conversion agent.

2. The light conversion-based regulation based aquaculture greenhouse film according to claim 1, characterized in that, The red-yellow light regulation layer is composed of 55-75.5wt% of the red-yellow light regulation layer substrate, 8-15.5wt% of the nano-silica coated rare earth light conversion agent, 1.5-3.5wt% of the flow agent, 9.5-16wt% of the filler, 1.5-3.6wt% of the light stabilizer, 1.2-2.8wt% of the antioxidant and 2.8-3.6wt% of the lubricant, with the total mass of the red-yellow light regulation layer being 100wt%; The blue light inhibition layer is composed of 68-75wt% of the blue light inhibition layer substrate, 10-15wt% of the blue light inhibitor, 5-7wt% of the filler, 1.5-3wt% of the light stabilizer, 4.5-6.5wt% of the toughening agent and 1-3wt% of the lubricant, with the total mass of the blue light inhibition layer being 100wt%; The support layer is composed of 89-94.5wt% of the support layer substrate, 3.3-7.2wt% of the crosslinking agent, 1.7-2.8wt% of the antioxidant and 0.5-1wt% of the lubricant, with the total mass of the support layer being 100wt%.

3. The light conversion-based regulation based aquaculture greenhouse film according to claim 1, characterized in that, In the red-yellow light regulation layer, the red-yellow light regulation layer substrate is composed of 22-30.5wt% of low-density polyethylene, 18-28.5wt% of linear low-density polyethylene and 15-16.5wt% of ethylene-vinyl acetate copolymer; the flow agent is one of polyglycerol fatty acid ester, octylphenol polyoxyethylene ether or glycerol monostearate; the filler is one of nano calcium carbonate, hydrotalcite or wollastonite; the light stabilizer is one of UV-531, UV-326 or UV-770; the antioxidant is one of antioxidant 245, antioxidant 1010 or antioxidant 1076; and the lubricant is erucic acid amide.

4. The light conversion based regulation greenhouse film for aquaculture according to claim 1, characterized in that, In the blue light inhibition layer, the blue light inhibition layer substrate is low-density polyethylene; the filler is one of nano calcium carbonate, hydrotalcite or wollastonite; the light stabilizer is one of UV-531, UV-326 or UV-770; the toughening agent is maleic anhydride grafted polyethylene; and the lubricant is erucic acid amide.

5. The light conversion based regulation greenhouse film for aquaculture according to claim 1, characterized in that, The support layer substrate is a polyolefin elastomer, the crosslinking agent is composed of 2.5-4.6 wt% of tert-amyl peroxy(2-ethylhexyl) carbonate and 0.8-2.6 wt% of triallyl isocyanurate, the antioxidant is one of antioxidant 245, antioxidant 1010 or antioxidant 1076, and the lubricant is erucic amide.

6. The light conversion based regulation greenhouse film for aquaculture according to claim 1, characterized in that, In step (1), the europium salt is europium chloride hexahydrate, the samarium salt is samarium chloride hexahydrate, the main ligand is 2-thiophenecarbonyl trifluoroacetone, the second ligand is o-phenanthroline, and the nucleating agent is nano cerium dioxide; the ratio of the europium salt, the samarium salt, the main ligand, the second ligand, the nucleating agent and the ethanol aqueous solution is 1:(1-1.25):(3.05-3.2):(1.02-1.1):(250-350):(5500-6500), wherein the europium salt, the samarium salt, the main ligand and the second ligand are in mol, the nucleating agent is in g, and the ethanol aqueous solution is in mL; the block copolymer is polylactic acid-polyethylene glycol-maleimide; the mass ratio of the block copolymer, the nucleating agent and tetraethyl orthosilicate is (400-800):(250-350):3500, wherein the nucleating agent, the block copolymer and tetraethyl orthosilicate are in g; and the pH is adjusted to 8.2-8.

4.

7. The light conversion based regulation greenhouse film for aquaculture according to claim 1, characterized in that, In step (2), when the tetraethyl orthosilicate / ethanol solution is added, the stirring rate is 550-750 rpm, the stirring rate during hydrolysis and condensation is 50-75 rpm, the hydrolysis and condensation temperature is 50-60℃, the hydrolysis and condensation pH is 8.2-8.4, and the hydrolysis and condensation time is 5-8 h.

8. A method for preparing the aquaculture greenhouse film based on light conversion regulation according to any one of claims 1-7, characterized in that, The method comprises the following steps: S1, respectively according to the proportioning of the red and yellow light regulation layer, the blue light inhibition layer and the support layer, mixing, melt granulation, to obtain the red and yellow light regulation layer master batch, the blue light inhibition layer master batch and the support layer master batch for standby; S2, the red and yellow light regulation layer master batch, the blue light inhibition layer master batch and the support layer master batch are prepared into the water product cultivation greenhouse film by co-extrusion blown film; 9. The method of claim 8, wherein the light conversion layer is prepared by a process comprising the steps of: (a) preparing a solution of a polymer and a light conversion material; (b) coating the solution on a substrate; (c) drying the solution to form a light conversion layer; and (d) removing the substrate. In S2, the co-extrusion blown film equipment used in the co-extrusion blown film includes an extrusion system, a co-extrusion die, a blowing system and a traction system, and the extrusion system includes a red and yellow light regulation layer section, a blue light inhibition layer section and a support layer section; the temperature of the feeding section of the red and yellow light regulation layer section is 135-145℃, the temperature of the melting section is 170-180℃, and the temperature of the homogenizing section is 185-195℃; the temperature of the feeding section of the blue light inhibition layer section is 150-160℃, the temperature of the melting section is 175-185℃, and the temperature of the homogenizing section is 185-195℃; the temperature of the feeding section of the support layer section is 135-145℃, the temperature of the melting section is 175-185℃, and the temperature of the homogenizing section is 180-190℃; the thickness of the water product cultivation greenhouse film is 0.070-0.100 mm, and the thickness ratio of the red and yellow light regulation layer, the blue light inhibition layer and the support layer is 1:1:1.

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