阅读说明：本技术 一种转光效果持久的塑料转光农膜及制备方法 (Plastic light conversion agricultural film with lasting light conversion effect and preparation method thereof ) 是由 吴广龙 于 2019-08-31 设计创作，主要内容包括：本发明涉及农用薄膜领域,公开了一种转光效果持久的塑料转光农膜及制备方法。包括如下制备过程：(1)将液态玻璃、去离子水、无机稀土光转换剂和陶瓷微球混合配制成浆料,接着喷雾造粒,制得复合无机稀土光转换剂；(2)将复合无机稀土光转换剂与基体树脂、增塑剂及抗氧剂混合均匀后用吹膜机吹膜,即可制得转光效果持久的塑料转光农膜。本发明得到球形复合无机稀土光转换剂在薄膜基体中利于均匀分散,不易造成团聚,改善了流动性,与基体树脂的相容性良好,化学性质稳定,表面不析出,外观光洁度好,耐水性优良,转光效果持久,得到的均匀性优良的农用薄膜,有效提高了塑料转光农膜的转光效率,应用范围广。(The invention relates to the field of agricultural films, and discloses a plastic light conversion agricultural film with a lasting light conversion effect and a preparation method thereof. The preparation method comprises the following preparation processes: (1) mixing liquid glass, deionized water, an inorganic rare earth light conversion agent and ceramic microspheres to prepare slurry, and then carrying out spray granulation to prepare a composite inorganic rare earth light conversion agent; (2) the composite inorganic rare earth light conversion agent, matrix resin, plasticizer and antioxidant are mixed uniformly and then blown by a film blowing machine to obtain the plastic light conversion agricultural film with lasting light conversion effect. The spherical composite inorganic rare earth light conversion agent obtained by the invention is beneficial to uniform dispersion in a film matrix, is not easy to cause agglomeration, improves the fluidity, has good compatibility with matrix resin, stable chemical property, no precipitation on the surface, good appearance smoothness, excellent water resistance and durable light conversion effect, and can effectively improve the light conversion efficiency of the plastic light conversion agricultural film, thereby having wide application range.)

1. a preparation method of a plastic light conversion agricultural film with a lasting light conversion effect is characterized by comprising the following specific steps:

(1) mixing liquid glass and deionized water, fully stirring to form a uniform system, adding an inorganic rare earth light conversion agent and ceramic microspheres into the system, soaking for 1-2 hours, uniformly stirring to prepare slurry, transferring the slurry into a pressure spray dryer for spray granulation, collecting particles, washing for 2-4 times by using absolute ethyl alcohol, heating and drying for 1-2 hours at 100-120 ℃, and fixing the inorganic rare earth light conversion agent on the surfaces of the ceramic microspheres through the solidification process of the liquid glass to prepare a composite inorganic rare earth light conversion agent;

(2) and (2) uniformly premixing the composite inorganic rare earth light conversion agent prepared in the step (1) with matrix resin, a plasticizer and an antioxidant, continuously uniformly mixing, extruding and granulating, and blowing a film by using a film blowing machine to obtain the plastic light conversion agricultural film with a lasting light conversion effect.

2. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: the inorganic rare earth light conversion agent in the step (1) is at least one of rare earth ion doped alkaline earth aluminate, oxide, sulfide, tungstate and silicate.

3. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: the ceramic microspheres in the step (1) are at least one of alumina ceramic microspheres, silica ceramic microspheres, silicon carbide ceramic microspheres and lithium silicate ceramic microspheres, and the particle size of the particles is 3-8 μm.

4. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: the raw material components in the step (1) comprise, by mass, 10-15% of liquid glass, 35-50% of deionized water, 15-20% of an inorganic rare earth light conversion agent and 25-30% of ceramic microspheres.

5. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: in the spray granulation process in the step (1), the temperature of a heat source of a pressure spray dryer is 180-200 ℃, the temperature of an outlet is 120-160 ℃, and the pump pressure is 1-2 MPa.

6. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: and (3) the matrix resin in the step (2) is one of polyethylene, polypropylene and polyvinyl chloride.

7. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: the plasticizer in the step (2) is at least one of dipropyl phthalate, dibutyl phthalate, diethyl phthalate and dimethyl phthalate, and the antioxidant is at least one of antioxidant 1010, antioxidant 1076, antioxidant 164, antioxidant CA, antioxidant DNP and antioxidant TPP.

8. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: and (3) in the film blowing process of the film blowing machine in the step (2), the melting temperature is 180-200 ℃, and the die head temperature is 160-180 ℃.

9. The method for preparing the plastic light conversion agricultural film with durable light conversion effect according to claim 1, which is characterized in that: the raw material components in the step (2) are, by mass, 1-2% of a composite inorganic rare earth light conversion agent, 92-95% of matrix resin, 2-4% of a plasticizer and 1-2% of an antioxidant.

10. A plastic light conversion agricultural film with a durable light conversion effect, which is prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of agricultural films, and discloses a plastic light conversion agricultural film with a lasting light conversion effect and a preparation method thereof.

Background

In recent years, the functionalization and high performance of agricultural films in China are becoming the mainstream of agricultural film development. The light conversion design principle of the agricultural film is based on the principle of optical ecology, and the light conversion agent is introduced into the agricultural film to realize light energy conversion, so that the light quality of the plastic greenhouse is improved, and the comprehensive utilization rate of light energy is improved. Compared with the common film and the existing functional film, the film has more obvious advantages in the aspects of crop yield increase, precocity, quality improvement and the like.

The light conversion function of the light conversion film is realized by adding the light conversion agent into the agricultural film, so the key for realizing the light energy conversion of the agricultural film and improving the transmission light quality lies in the development of the light conversion agent. Light conversion agents belong to photoluminescent materials and are generally classified into organic dyes, inorganic salts, complexes and the like according to the light conversion conditions, and have different application characteristics. Compared with organic compounds, the inorganic salt has low price, easy preparation and storage, good high temperature resistance and wide application of the inorganic salt light conversion agent.

Common inorganic light conversion agents are alkaline earth aluminates, oxides, sulfides, tungstates, silicates and the like doped with rare earth ions or heavy metal ions. Wherein, the inorganic compound forms regular crystal lattice, and the introduced rare earth ions or heavy metal ions are in the crystal lattice to play the role of activator. Light is emitted by the interaction of these metal centers with the crystal lattice. The research subject of the light conversion agent for the light conversion agricultural film mainly focuses on improving the light conversion efficiency and the light conversion effect.

Chinese patent application No. 201811309258.4 discloses a plant light conversion film and a preparation method and application thereof. The plant light conversion film comprises a plastic film and a composite material coated on the plastic film, wherein the composite material comprises resin and fluorescent powder, and the fluorescent powder is MAL12-xO19: xTM, wherein M is Sr2+ or Ca2+, and TM is Ti3+ or Cr3 +; x is 0.001 to 0.1. The plant light conversion film provided by the invention can convert green part light which plays a small role in plant growth into near infrared light, is beneficial to plant growth, can be widely popularized and applied to the field of plant cultivation, and has great economic value. .

Chinese patent application No. 201810213079.4 discloses a red light conversion film based on rare earth europium complex and a preparation method and application thereof, belonging to the technical field of agricultural light conversion films. The red light conversion film is prepared from raw materials consisting of rare earth europium organic complex light conversion agent [ Eu (2-HBI) (phen)3] Cl3, dispersing agent, organic solvent and low-density polyethylene according to a certain percentage. The preparation method of the red light conversion film comprises the steps of soaking a certain amount of [ Eu (2-HBI) (phen)3] Cl3 by using an organic solvent, adding a certain amount of dispersing agent into low-density polyethylene particles, uniformly mixing, carrying out hot melting and mixing, and finally carrying out blow molding to form a film according to a certain blow-up ratio.

According to the above, although the pure inorganic rare earth light conversion agent in the existing scheme improves the light conversion intensity and prolongs the service life, some defects still exist, such as poor light stability, fast light conversion attenuation, reduction of light transmittance along with the time extension, and the like, especially the dispersibility of common inorganic salt in a high polymer film is not good, so that the formed film has poor uniformity, the appearance smoothness of the product is influenced, rare earth agglomeration is caused, and the light conversion efficiency of the film is reduced.

Disclosure of Invention

In the prior widely applied plastic light conversion agricultural film, the inorganic rare earth light conversion agent has poor dispersibility in a high molecular film, so that the uniformity of the film is poor, and the appearance smoothness and the light conversion effect of the light conversion agricultural film are influenced.

In order to solve the problems, the invention adopts the following technical scheme:

a preparation method of a plastic light conversion agricultural film with a lasting light conversion effect comprises the following specific steps:

(1) mixing liquid glass and deionized water, fully stirring to form a uniform system, adding an inorganic rare earth light conversion agent and ceramic microspheres into the system, soaking for 1-2 hours, uniformly stirring to prepare slurry, transferring the slurry into a pressure spray dryer for spray granulation, collecting particles, washing for 2-4 times by using absolute ethyl alcohol, heating and drying for 1-2 hours at 100-120 ℃, and fixing the inorganic rare earth light conversion agent on the surfaces of the ceramic microspheres through the solidification process of the liquid glass to prepare a composite inorganic rare earth light conversion agent;

(2) and (2) uniformly premixing the composite inorganic rare earth light conversion agent prepared in the step (1) with matrix resin, a plasticizer and an antioxidant, continuously uniformly mixing, extruding and granulating, and blowing a film by using a film blowing machine to obtain the plastic light conversion agricultural film with a lasting light conversion effect.

The inorganic rare earth light conversion agent is a light conversion agent consisting of a matrix and a dopant, wherein the crystal of the matrix has certain defects, the anion and the cation of the matrix are optically transparent, the cation simultaneously has a closed shell electronic structure, and the dopant comprises an activator, a sensitizer, a coactivator and a cosolvent. The rare earth atoms have a special outer electronic layer structure, rich energy levels and 4f electronic transition characteristics, so that the rare earth atoms have an excellent energy conversion function. The photoluminescence process of the inorganic rare earth light conversion agent consists of three parts: absorption of light, energy transfer, reflection of light. When the light conversion agent is irradiated by sunlight, the rare earth ions are used as luminescence centers to absorb energy, outer layer electrons generate f-f transition and/or f-d transition, the transition is carried out from a ground state to an excited state, and energy difference is released in the form of light energy and heat energy in the process that the electrons are transited from the excited state to the ground state. Preferably, the inorganic rare earth light-converting agent in step (1) is at least one of rare earth ion-doped alkaline earth aluminate, oxide, sulfide, tungstate and silicate.

The liquid glass is nano-scale dispersed silicon dioxide, can form an invisible hydrophobic layer with strong repulsion to water to generate strong electrostatic attraction, and fixes the liquid glass on the sprayed material. In addition, the ceramic microspheres are used as light conversion agent carriers, and have the advantages of high sphericity, high strength, stable chemical properties, regular morphological structure, good fluidity and the like. The inorganic rare earth light conversion agent is fixed on the surface of the ceramic microsphere carrier by liquid glass. Preferably, the ceramic microspheres in the step (1) are at least one of alumina ceramic microspheres, silica ceramic microspheres, silicon carbide ceramic microspheres and lithium silicate ceramic microspheres, and the particle size of the ceramic microspheres is 3-8 μm. Furthermore, the raw material components comprise, by mass, 10-15% of liquid glass, 35-50% of deionized water, 15-20% of an inorganic rare earth light conversion agent and 25-30% of ceramic microspheres.

The process of spray granulation has the advantage of high drying speed, the surface area of the material liquid is greatly increased after atomization, 95-98% of water can be instantly evaporated in hot air flow, the drying time is only ten seconds to tens of seconds, the spray granulation drying device is particularly suitable for drying heat-sensitive materials, the obtained product is spherical particles, the particle size is uniform, the fluidity is good, the solubility is good, the product purity is high, and the quality is good. The invention utilizes a spray granulation process, and the inorganic rare earth light conversion agent is fixed on the surface of the ceramic microsphere carrier by liquid glass to obtain the spherical filler, so that the spherical filler is beneficial to uniform dispersion in a film matrix, is not easy to cause agglomeration, and has the advantages of good fluidity, good compatibility with matrix resin, stable chemical property, no surface precipitation, good appearance finish, excellent water resistance and lasting light conversion effect. Preferably, in the spray granulation process in the step (1), the heat source temperature of the pressure spray dryer is 180-200 ℃, the outlet temperature is 120-160 ℃, and the pump pressure is 1-2 MPa.

Preferably, in the present invention, the matrix resin in step (2) is one of polyethylene, polypropylene and polyvinyl chloride.

In a preferred embodiment of the present invention, the plasticizer in step (2) is at least one selected from dipropyl phthalate, dibutyl phthalate, diethyl phthalate, and dimethyl phthalate.

In the present invention, the antioxidant in step (2) is preferably at least one of antioxidant 1010, antioxidant 1076, antioxidant 164, antioxidant CA, antioxidant DNP, and antioxidant TPP.

Preferably, in the film blowing process of the film blowing machine in the step (2), the melting temperature is 180-200 ℃, and the die head temperature is 160-180 ℃.

Preferably, the raw material components in the step (2) comprise, by mass, 1-2% of the composite inorganic rare earth light conversion agent, 92-95% of the matrix resin, 2-4% of the plasticizer and 1-2% of the antioxidant.

Further, the method is simple. The invention provides a plastic light conversion agricultural film with lasting light conversion effect, which is prepared by the method, liquid glass and deionized water are mixed and stirred to form a uniform system, meanwhile, an inorganic rare earth light conversion agent and ceramic microspheres are added into a liquid glass solution for dipping, the prepared slurry is stirred and moved into a pressure spray dryer for spray granulation, the particles are collected and washed by absolute ethyl alcohol, and are heated and dried, and the inorganic rare earth light conversion agent is fixed on the surfaces of the ceramic microspheres through the solidification process of the liquid glass to prepare a composite inorganic rare earth light conversion agent; and uniformly mixing the composite inorganic rare earth light conversion agent, matrix resin, a plasticizer and an antioxidant, and then blowing a film by using a film blowing machine. The obtained spherical composite light conversion agent has good dispersibility in a plastic matrix, good fluidity and stable chemical property, and the obtained light conversion agricultural film has good appearance smoothness, excellent water resistance and lasting light conversion effect.

Compared with the prior art, the invention provides the plastic light conversion agricultural film with durable light conversion effect and the preparation method thereof, and the outstanding characteristics and excellent effects are as follows:

1. provides a method for preparing plastic light conversion agricultural film with lasting light conversion effect by fixing the light conversion agent on ceramic microspheres to prepare the composite light conversion agent.

2. The inorganic rare earth light conversion agent is fixed on the surface of the ceramic microsphere carrier by liquid glass, so that the obtained spherical filler is beneficial to uniform dispersion in a film matrix, is not easy to cause agglomeration, improves the fluidity, has good compatibility with matrix resin, stable chemical property, no surface precipitation, good appearance finish, excellent water resistance and lasting light conversion effect.

3. The agricultural film prepared by the method has excellent uniformity, effectively improves the light conversion efficiency of the plastic light conversion film, and has wide application range.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.