阅读说明：本技术 一种缓控释涂层和一种缓控释地膜及其制备方法 (Sustained and controlled release coating, sustained and controlled release mulching film and preparation method thereof ) 是由 王珂 陈骏佳 谢东 孙晓燕 李圆 赵阳 于 2020-06-04 设计创作，主要内容包括：本发明提供了一种缓控释涂层和一种缓控释地膜及其制备方法,属于农用薄膜技术领域。本发明提供了一种缓控释涂层,由涂层液制备得到,所述涂层液包括活性纳米颗粒、成膜物质、助剂和水；其中,所述活性纳米颗粒包括功能性纳米粒子和包裹在功能性纳米粒子表面的聚多巴胺外壳,所述聚多巴胺外壳由多巴胺在功能性纳米粒子表面原位聚合得到；形成所述功能性纳米粒子的功能性成分包括除草剂、杀虫剂和杀菌剂中的至少一种。本发明利用聚多巴胺包裹功能性纳米粒子形成活性纳米颗粒,在实际使用过程中,功能性纳米粒子可以透过聚多巴胺外壳缓慢释放,达到缓控释的效果；而且所述聚多巴胺外壳由多巴胺在功能性纳米粒子表面原位聚合得到,操作简单、成本低。(The invention provides a sustained and controlled release coating, a sustained and controlled release mulching film and a preparation method thereof, belonging to the technical field of agricultural films. The invention provides a sustained and controlled release coating which is prepared from coating liquid, wherein the coating liquid comprises active nano particles, a film forming substance, an auxiliary agent and water; the active nanoparticles comprise functional nanoparticles and polydopamine shells wrapped on the surfaces of the functional nanoparticles, wherein the polydopamine shells are obtained by in-situ polymerization of dopamine on the surfaces of the functional nanoparticles; the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, a pesticide, and a bactericide. The invention utilizes polydopamine to wrap functional nanoparticles to form active nanoparticles, and in the actual use process, the functional nanoparticles can be slowly released through a polydopamine shell to achieve the effect of slow and controlled release; and the poly-dopamine shell is obtained by in-situ polymerization of dopamine on the surface of the functional nano particle, and has simple operation and low cost.)

1. A sustained and controlled release coating is prepared from a coating liquid, and is characterized in that the coating liquid comprises active nano particles, a film forming substance, an auxiliary agent and water;

the active nanoparticles comprise functional nanoparticles and polydopamine shells wrapped on the surfaces of the functional nanoparticles, and the polydopamine shells are obtained by in-situ polymerization of dopamine on the surfaces of the functional nanoparticles;

the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, a pesticide, and a bactericide.

2. The sustained-release coating according to claim 1, wherein the particle size of the active nanoparticles is 50 to 300nm, and the thickness of the polydopamine shell in the active nanoparticles is 10 to 80 nm.

3. The sustained-release coating according to claim 2, wherein the preparation method of the active nanoparticles comprises the following steps:

dissolving a functional component in an organic solvent, adding the obtained functional component solution into water, and performing ultrasonic treatment to obtain a functional nanoparticle dispersion liquid;

mixing the functional nano particle dispersion liquid, dopamine hydrochloride aqueous solution and Tris-HCl buffer solution to enable the pH value of the obtained mixed feed liquid to be 7.5-9.5, and then carrying out polymerization reaction to obtain a polymerization product system;

and (3) dialyzing and drying the polymerization product system in sequence to obtain the active nano particles.

4. The sustained-release coating according to claim 3, wherein the concentration of the functional ingredient in the functional nanoparticle dispersion is 0.01-100 mg/mL, and the concentration of dopamine hydrochloride in the dopamine hydrochloride aqueous solution is 5-20 mg/mL; the volume ratio of the functional nanoparticle dispersion liquid to the dopamine hydrochloride aqueous solution is 100: (1-5).

5. The sustained and controlled release coating according to claim 3, wherein the polymerization reaction is carried out under the conditions of light shielding and room temperature, and the time of the polymerization reaction is 10-30 h.

6. The sustained-release coating of claim 3, wherein the method of dialysis comprises the steps of:

the polymerization product system is filled into a dialysis bag, and then the dialysis bag filled with the polymerization product system is placed in a saturated aqueous solution of the functional ingredient for dialysis.

7. The controlled release coating according to any one of claims 1 to 6, wherein the coating solution contains 1 to 10 wt% of active nanoparticles, 1 to 20 wt% of film-forming material, and 0.2 to 2 wt% of auxiliary agent.

8. The slow/controlled release mulching film is characterized by comprising a mulching film substrate and a slow/controlled release coating arranged on one side of the mulching film substrate; wherein the controlled release coating is the controlled release coating of any one of claims 1 to 7.

9. The preparation method of the sustained-release mulching film of claim 8, comprising the following steps:

and coating the coating liquid on the single surface of the mulching film substrate, and forming a sustained and controlled release coating on the single surface of the mulching film substrate after drying to obtain the sustained and controlled release mulching film.

10. The method according to claim 9, wherein the coating liquid is applied in an amount of 2 to 30mL/m²。

Technical Field

The invention relates to the technical field of agricultural films, in particular to a sustained and controlled release coating, a sustained and controlled release mulching film and a preparation method thereof.

Background

With the progress of science and technology, the requirements of people on agricultural mulching films are higher and higher, various novel mulching films are continuously appeared, wherein the agricultural mulching films containing functional components such as herbicides are produced at the same time, and the functional components in the mulching films can be introduced through a coating technology so as to reduce the environmental pollution and waste caused by high-temperature volatilization of the functional components in the film blowing process. There are two main ways of introducing functional ingredients by coating techniques in the prior art: firstly, functional components are directly added into the coating, but the method has the problem of too fast release of the functional components, so that the effective use time of the mulching film is shortened; secondly, the functional components are loaded by the nano particles and then added into the coating, although the method realizes the slow release of the functional components to a certain extent, the method needs to firstly prepare the nano particles (such as mesoporous silica nano particles and the like) and then add the loaded functional components into the coating, and the method has the disadvantages of complicated steps, high preparation cost and no contribution to large-scale production.

Disclosure of Invention

The invention aims to provide a sustained-release coating, a sustained-release mulching film and a preparation method thereof, wherein the invention utilizes polydopamine to coat functional nanoparticles, and the functional nanoparticles can be slowly released through a polydopamine shell to achieve the effect of sustained and controlled release; and the poly-dopamine shell is obtained by in-situ polymerization of dopamine on the surface of the functional nano particle, and has simple operation and low cost.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a sustained and controlled release coating which is prepared from coating liquid, wherein the coating liquid comprises active nano particles, a film forming substance, an auxiliary agent and water;

the active nanoparticles comprise functional nanoparticles and polydopamine shells wrapped on the surfaces of the functional nanoparticles, and the polydopamine shells are obtained by in-situ polymerization of dopamine on the surfaces of the functional nanoparticles;

the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, a pesticide, and a bactericide.

Preferably, the particle size of the active nanoparticles is 50-300 nm, and the thickness of the polydopamine shell in the active nanoparticles is 10-80 nm.

Preferably, the preparation method of the active nanoparticles comprises the following steps:

dissolving a functional component in an organic solvent, adding the obtained functional component solution into water, and performing ultrasonic treatment to obtain a functional nanoparticle dispersion liquid;

mixing the functional nano particle dispersion liquid, dopamine hydrochloride aqueous solution and Tris-HCl buffer solution to enable the pH value of the obtained mixed feed liquid to be 7.5-9.5, and then carrying out polymerization reaction to obtain a polymerization product system;

and (3) dialyzing and drying the polymerization product system in sequence to obtain the active nano particles.

Preferably, the concentration of the functional component in the functional nanoparticle dispersion liquid is 0.01-100 mg/mL, and the concentration of dopamine hydrochloride in the dopamine hydrochloride aqueous solution is 5-20 mg/mL; the volume ratio of the functional nanoparticle dispersion liquid to the dopamine hydrochloride aqueous solution is 100: (1-5).

Preferably, the polymerization reaction is carried out under the conditions of light shielding and room temperature, and the time of the polymerization reaction is 10-30 h.

Preferably, the method of dialysis comprises the steps of:

the polymerization product system is filled into a dialysis bag, and then the dialysis bag filled with the polymerization product system is placed in a saturated aqueous solution of the functional ingredient for dialysis.

Preferably, the content of the active nano particles in the coating liquid is 1-10 wt%, the content of the film forming substance is 1-20 wt%, and the content of the auxiliary agent is 0.2-2 wt%.

The invention provides a sustained and controlled release mulching film, which comprises a mulching film substrate and a sustained and controlled release coating arranged on one side of the mulching film substrate; wherein, the controlled release coating is the controlled release coating of the technical scheme.

The invention provides a preparation method of a sustained and controlled release mulching film, which comprises the following steps:

and coating the coating liquid on the single surface of the mulching film substrate, and forming a sustained and controlled release coating on the single surface of the mulching film substrate after drying to obtain the sustained and controlled release mulching film.

Preferably, the coating amount of the coating liquid is 2-30 mL/m²。

The invention provides a sustained and controlled release coating which is prepared from coating liquid, wherein the coating liquid comprises active nano particles, a film forming substance, an auxiliary agent and water; the active nanoparticles comprise functional nanoparticles and polydopamine shells wrapped on the surfaces of the functional nanoparticles, and the polydopamine shells are obtained by in-situ polymerization of dopamine on the surfaces of the functional nanoparticles; the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, a pesticide, and a bactericide. The invention utilizes polydopamine to wrap functional nanoparticles to form active nanoparticles, and in the actual use process, the functional nanoparticles can be slowly released through a polydopamine shell to achieve the effect of slow and controlled release; in addition, the active nano particles form a polydopamine shell on the surface of the functional nano particles by in-situ polymerization of dopamine, so that the functional nano particles are wrapped to form the active nano particles, and the method is simple to operate and low in cost; in addition, the active nano particles have good water dispersibility, can directly use water as a dispersing agent to obtain a coating liquid, and is environment-friendly and pollution-free.

Drawings

FIG. 1 is a graph showing the particle size distribution of active nanoparticles prepared in example 1;

FIG. 2 is a release profile of functional ingredients from the mulch film prepared in example 1;

FIG. 3 is a release profile of functional ingredients from the mulch film prepared in example 2;

FIG. 4 is a release profile of functional ingredients from the mulch film prepared in example 3;

fig. 5 is a release profile of functional ingredients in the mulching film prepared in comparative example 1;

fig. 6 is a release profile of functional ingredients in the mulching film prepared in comparative example 2;

fig. 7 is a release profile of the functional ingredient in the mulching film prepared in comparative example 3.

Detailed Description

The invention provides a sustained and controlled release coating which is prepared from coating liquid, wherein the coating liquid comprises active nano particles, a film forming substance, an auxiliary agent and water;

the active nanoparticles comprise functional nanoparticles and polydopamine shells wrapped on the surfaces of the functional nanoparticles, and the polydopamine shells are obtained by in-situ polymerization of dopamine on the surfaces of the functional nanoparticles;

the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, a pesticide, and a bactericide.

The coating liquid provided by the invention comprises active nano particles, wherein the active nano particles comprise functional nano particles and a polydopamine shell coated on the surfaces of the functional nano particles; the poly-dopamine shell is obtained by in-situ polymerization of dopamine on the surface of the functional nano particle. In the invention, the particle size of the active nanoparticles is preferably 50-300 nm, and more preferably 50-100 nm; the thickness of the polydopamine shell is preferably 10-80 nm, and more preferably 10-40 nm.

In the present invention, the functional ingredient forming the functional nanoparticles includes at least one of a herbicide, an insecticide, and a bactericide, preferably a herbicide, an insecticide, or a bactericide; the invention has no special limitation on the specific types of the herbicide, the pesticide and the bactericide, and the pesticide well known to the technical personnel in the field can be adopted, wherein the herbicide can be acetochlor specifically, the pesticide can be pyrethrin specifically, and the bactericide can be prochloraz specifically.

In the present invention, the preparation method of the active nanoparticle preferably comprises the following steps:

dissolving a functional component in an organic solvent, adding the obtained functional component solution into water, and performing ultrasonic treatment to obtain a functional nanoparticle dispersion liquid;

mixing the functional nano particle dispersion liquid, dopamine hydrochloride aqueous solution and Tris-HCl buffer solution to enable the pH value of the obtained mixed feed liquid to be 7.5-9.5, and then carrying out polymerization reaction to obtain a polymerization product system;

and (3) dialyzing and drying the polymerization product system in sequence to obtain the active nano particles.

The functional component is dissolved in an organic solvent, and the obtained functional component solution is added into water for ultrasonic treatment to obtain the functional nanoparticle dispersion liquid. In the present invention, the organic solvent is preferably methanol or ethanol; in the embodiment of the invention, anhydrous methanol or anhydrous ethanol is specifically used as an organic solvent to dissolve the functional components. In the invention, the volume ratio of the organic solvent to water is preferably (1-10): (90-99), more preferably (1-5): (95-99). In the invention, the concentration of the functional component in the functional nanoparticle dispersion liquid is preferably 0.01-100 mg/mL, more preferably 0.01-20 mg/mL, and further preferably 0.05-5 mg/mL; the concentration of the functional component in the functional nanoparticle dispersion liquid is too high, and after subsequent polymerization reaction, nanoparticles in the system are easy to agglomerate and precipitate, so that the stability of the finally obtained active nanoparticles is poor.

Dissolving functional components in an organic solvent, preferably quickly adding the obtained functional component solution into water for ultrasonic treatment, and realizing the molding of functional nanoparticles through the sudden change of the solvent environment to obtain a functional nanoparticle dispersion liquid; specifically, the functional ingredient solution may be immediately subjected to the ultrasonic treatment after being rapidly added to the water, or the functional ingredient solution may be directly and rapidly added to the water in an ultrasonic state. In the invention, the frequency of the ultrasonic wave is preferably 35-45 kHz, and more preferably 40 kHz; the time of the ultrasonic treatment is preferably 15-25 s, and more preferably 20 s. The invention preferably carries out ultrasonic treatment under the conditions, which is beneficial to ensuring that the functional nano particle dispersion liquid with uniform granularity and uniform dispersion is obtained.

After the functional nanoparticle dispersion liquid is obtained, the functional nanoparticle dispersion liquid, dopamine hydrochloride aqueous solution and Tris-HCl buffer solution are mixed to enable the pH value of the obtained mixed feed liquid to be 7.5-9.5, and then polymerization reaction is carried out to obtain a polymerization product system. In the invention, the concentration of the dopamine hydrochloride in the dopamine hydrochloride aqueous solution is preferably 5-20 mg/mL, and more preferably 5-10 mg/mL; the concentration of dopamine hydrochloride in the dopamine hydrochloride aqueous solution is too high, and after subsequent polymerization reaction, nano particles in the system are easy to agglomerate and precipitate, so that the stability of the finally obtained active nano particles is poor. In the present invention, the volume ratio of the functional nanoparticle dispersion liquid to the dopamine hydrochloride aqueous solution is preferably 100: (1-5), more preferably 100: 1.

in the invention, the concentration of the Tris-HCl buffer solution is preferably 5-20 mg/mL, and more preferably 5-10 mg/mL. The polymerization reaction is carried out under the condition that the pH value is 7.5-9.5 (preferably 8.5), so that the dopamine is favorably and fully polymerized, and a stable polydopamine wrapping layer is further formed. In the invention, the addition amount of the Tris-HCl buffer solution can meet the requirement that the pH value of the system is higher than the above requirement, and preferably, the volume ratio of the Tris-HCl buffer solution to the dopamine hydrochloride aqueous solution is 1: 1.

in the present invention, the polymerization reaction is preferably carried out under ambient temperature conditions protected from light; the room temperature does not need to be heated or cooled additionally, and in the embodiment of the invention, the polymerization reaction is carried out at 25 ℃; the time of the polymerization reaction is preferably 10-30 h, and more preferably 24 h. The polymerization reaction is carried out under the condition of keeping out of the sun, which is favorable for preventing dopamine hydrochloride from being oxidized and ensuring the smooth proceeding of the polymerization reaction. In the invention, in the polymerization reaction process, dopamine hydrochloride is subjected to in-situ polymerization to form a polydopamine shell on the surface of the functional nanoparticles, so that the functional nanoparticles are wrapped to form active nanoparticles, and in the actual use process, functional components can be slowly released through the polydopamine shell to achieve the effect of sustained and controlled release.

After the polymerization reaction is finished, the polymerization product system is dialyzed and dried in sequence to obtain the active nano particles. In the present invention, the method of dialysis preferably comprises the steps of: the polymerization product system is filled into a dialysis bag, and then the dialysis bag filled with the polymerization product system is placed in a saturated aqueous solution of the functional ingredient for dialysis. In the present invention, the dialysis bag preferably has a molecular weight cut-off of 3500; the dialysis is preferably performed at room temperature, and the dialysis time is preferably 45-55 h, and more preferably 48 h.

After the dialysis is finished, the invention preferably dries the feed liquid in the dialysis bag to obtain active nano particles; the drying is preferably freeze drying, and the freeze drying time is preferably 20-30 hours, and more preferably 24 hours.

In the invention, the content of the active nanoparticles in the coating liquid is preferably 1-10 wt%, and more preferably 1-5 wt%.

The coating liquid provided by the invention comprises a film-forming substance; the present invention is not particularly limited in the kind of the film-forming material, and a film-forming material known to those skilled in the art may be used, specifically, polyvinyl alcohol or polyethylene glycol. In the present invention, the content of the film forming substance in the coating liquid is preferably 1 to 20 wt%, more preferably 1 to 10 wt%.

The coating liquid provided by the invention comprises an auxiliary agent, wherein the auxiliary agent preferably comprises a light stabilizer and/or a cross-linking agent, the light stabilizer preferably comprises one or more of carbon black, o-hydroxybenzophenone and bis (2,2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate, and the cross-linking agent preferably comprises one or more of borax, sodium sulfate and polyacrylic acid; the content of the auxiliary agent is preferably 0.2-2 wt%.

The coating liquid provided by the invention comprises water, and the water is not particularly limited in the invention and can be water well known to those skilled in the art. The invention uses water as the dispersant of the coating liquid, and is environment-friendly and pollution-free.

According to the invention, the components are preferably controlled in the addition amount, and the functional components have better slow release effect when the coating is prepared by using the obtained coating liquid.

The preparation method of the coating liquid is not specially limited, and all the components are uniformly mixed.

The preparation method of the sustained and controlled release coating is not specially limited, and the sustained and controlled release coating with proper thickness can be prepared according to actual requirements by coating the coating liquid.

The invention provides a sustained and controlled release mulching film, which comprises a mulching film substrate and a sustained and controlled release coating arranged on one side of the mulching film substrate; wherein, the controlled release coating is the controlled release coating of the scheme. The invention has no special limitation on the specific type and thickness of the mulching film substrate, and the substrate which is well known by the technicians in the field can be adopted; in the embodiment of the invention, a polybutylene adipate terephthalate (PBAT)/polylactic acid (PLA) composite film with the thickness of 100 mu m is specifically adopted as the mulching film substrate.

The thickness of the controlled release coating in the controlled release mulching film is not specially limited and can be selected according to actual needs. In the invention, the sustained-release coating is arranged on one side of the sustained-release mulching film, and when the sustained-release mulching film is used, the side provided with the sustained-release coating is specifically towards the ground so as to ensure that the functional components can fully play a role.

The invention provides a preparation method of the sustained and controlled release mulching film, which comprises the following steps:

and coating the coating liquid on the single surface of the mulching film substrate, and forming a sustained and controlled release coating on the single surface of the mulching film substrate after drying to obtain the sustained and controlled release mulching film.

In the invention, the coating liquid used for preparing the sustained-release mulching film is the coating liquid used for preparing the sustained-release coating in the scheme, and the specific component types and the proportion thereof are preferably consistent with the optional range of the coating liquid in the scheme, and are not described again here.

In the invention, the mulching film substrate is preferably pretreated before use, and is more preferably pretreated by a plasma cleaning machine; the invention has no special limitation on the specific operation steps and parameters of the pretreatment, can remove surface impurities and ensure that the subsequent coating is smoothly carried out.

The specific manner of coating is not particularly limited in the present invention, and uniform coating of the coating liquid can be achieved by a coating method well known to those skilled in the art. In the present invention, the coating means preferably includes spray coating, spin coating, roll coating, blade coating, pulling or hand coating; in the embodiment of the invention, the coating liquid is coated on one side of the mulching film substrate by using a coating rod.

The amount of the coating liquid is not particularly limited in the present invention, and the coating liquid may be applied as required. In the invention, the coating amount of the coating liquid is preferably 2-30 mL/m²(i.e. the volume of the coating liquid coated on each square meter of the mulching film substrate is 2-30 mL), and more preferably 10-20 mL/m²。

The drying method of the present invention is not particularly limited, and a drying method, that is, conditions well known to those skilled in the art may be used. In the invention, the drying temperature is preferably 55-65 ℃, and more preferably 60 ℃; the time is preferably 50-70 min, and more preferably 60 min.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.