阅读说明：本技术 一种可控溶解时间的农用地膜及制备方法 (Agricultural mulching film with controllable dissolving time and preparation method thereof ) 是由 黄永新 于 2020-05-28 设计创作，主要内容包括：本发明涉及一种可控溶解时间的农用地膜及制备方法,属于膜加工技术领域；由以下重量份的组分制成：天然直链淀粉30-75份、羧甲基纤维素1-10份、丙三醇5-30份、改性聚乙烯醇10-30份、二乙二醇0.1-2份、双油酸酯1-6份、硬脂酸0.1-2份、苯甲酸钠0.1-1.5份、苯甲酰胺0.1-5份、钛白粉0.1-1.5份、水15-17份；其制备方法包括(1)物料混合：将原料经高速混合机加温进行混合；(2)挤出：将混合物料通过喂料机加入挤出机,采用双螺杆的挤出机,进行挤出造粒,搅拌；(3)吹膜：采用单螺杆挤出机对颗粒进行吹膜,得到薄膜；本发明原料天然,方法简单,制备的产品具有很好的保温性,同时具有水溶解性,在45天-80天的可控溶解时间,且成本低,节能环保。(The invention relates to an agricultural mulching film with controllable dissolving time and a preparation method thereof, belonging to the technical field of film processing; the composition is prepared from the following components in parts by weight: 30-75 parts of natural amylose, 1-10 parts of carboxymethyl cellulose, 5-30 parts of glycerol, 10-30 parts of modified polyvinyl alcohol, 0.1-2 parts of diethylene glycol, 1-6 parts of dioleate, 0.1-2 parts of stearic acid, 0.1-1.5 parts of sodium benzoate, 0.1-5 parts of benzamide, 0.1-1.5 parts of titanium dioxide and 15-17 parts of water; the preparation method comprises the following steps of (1) mixing materials: heating and mixing the raw materials by a high-speed mixer; (2) extruding: adding the mixed material into an extruder through a feeding machine, extruding and granulating by adopting a double-screw extruder, and stirring; (3) film blowing: blowing the particles by a single-screw extruder to obtain a film; the invention has natural raw materials and simple method, and the prepared product has good heat preservation and water solubility, controllable dissolution time of 45-80 days, low cost, energy saving and environmental protection.)

1. An agricultural mulching film with controllable dissolving time is characterized in that: the mulching film is prepared from the following components in parts by weight:

30-75 parts of natural amylose, 1-10 parts of carboxymethyl cellulose, 5-30 parts of glycerol, 10-30 parts of modified polyvinyl alcohol, 0.1-2 parts of diethylene glycol, 1-6 parts of dioleate, 0.1-2 parts of stearic acid, 0.1-1.5 parts of sodium benzoate, 0.1-5 parts of benzamide, 0.1-1.5 parts of titanium dioxide and 15-17 parts of water.

2. An agricultural mulch film with a controlled dissolution time as claimed in claim 1 wherein: the natural amylose is cassava starch.

3. An agricultural mulch film with a controlled dissolution time as claimed in claim 1 wherein: the modified polyvinyl alcohol is obtained by mixing and modifying 1-10 parts of polyvinyl alcohol 1799 and 1-20 parts of polyvinyl alcohol 1788.

4. A preparation method of an agricultural mulching film with controllable dissolution time is characterized by comprising the following steps: the method comprises the following steps:

(1) mixing materials: 30-75 parts of natural amylose, 1-10 parts of carboxymethyl cellulose, 5-30 parts of glycerol, 10-30 parts of modified polyvinyl alcohol, 0.1-2 parts of diethylene glycol, 1-6 parts of dioleate, 0.1-2 parts of stearic acid, 0.1-1.5 parts of sodium benzoate, 0.1-5 parts of benzamide, 0.1-1.5 parts of titanium dioxide and 15-17 parts of water, and heating to 50-75 ℃ by a high-speed mixer for mixing;

(2) extruding: adding the mixed material into an extruder through a feeder, and performing extrusion granulation by adopting a double-screw extruder at the rotating speed of 100-;

(3) film blowing: and (3) blowing the film on the particles obtained in the step (2) by adopting a single-screw extruder to obtain a film with the thickness of 15 +/-2-25 +/-3 mu m.

5. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: the rotating speed of the feeder in the step (2) is 10-30r/min, the rotating speed of a screw of the extruder is 50-100r/min, and the working temperature of the extruder is 110-.

6. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: the length-diameter ratio of the double-screw extruder in the step (2) is 48: 1.

7. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: the length-diameter ratio of the single-screw extruder in the step (3) is 36: 1.

8. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: the working temperature of the single-screw extruder in the step (3) is 110-170 ℃.

9. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: the blowing ratio of the blown film in the step (3) is 1: 4-8.

10. The preparation method of the agricultural mulching film with the controllable dissolution time as claimed in claim 4, wherein the preparation method comprises the following steps: and (4) the film blowing drafting speed in the step (3) is 2 +/-0.4 m/min.

Technical Field

The invention relates to an agricultural mulching film and a preparation method thereof, in particular to a preparation method of an agricultural mulching film with controllable dissolving time, and belongs to the technical field of film processing.

Background

An agricultural mulching film is a film used for preventing water loss of plants in agricultural production. Most mulching films are made of high molecular polyvinyl compounds and resins thereof. It features high molecular weight, high corrosion resistance and stability. The current agricultural mulching film has poor photodegradability and biodegradability and is not easy to decay, so the residual mulching film is left in the ground in an independent form. According to research, the residual mulching film can be stored in the soil for hundreds of years without manual treatment. Farmers can not effectively recover the mulching film after using the mulching film, and the residual quantity of the mulching film is increased with the increase of the using quantity of the mulching film every year, thereby causing irreversible pollution to agricultural environment.

With the progress of the technology, the biodegradable mulching film becomes a research hotspot, and the main characteristic is that after the mulching film plays a role, the biodegradable mulching film can be automatically degraded into pollution-free micromolecule substances after a certain time, so that the harm of residual mulching film to soil and crops is effectively avoided. Generally, the mulching film can be classified into a photodegradable mulching film, a biodegradable mulching film and a photodegradable/biodegradable mulching film according to different objective conditions and mechanisms for causing degradation. Since the concept of degrading plastics was proposed in developed countries such as europe, america and japan in the 70 th 20 th century, scientists of various countries have developed polymeric mulch materials with photodegradation and biodegradation successively. The photodegradation mulching film is prepared by introducing a photodegradation auxiliary agent into a PE matrix, and triggering macromolecular chains to break to generate micromolecular compounds after the photodegradation auxiliary agent is excited by ultraviolet light. The degradation rate of the photodegradable mulching film is easily influenced by the external environment, the PE molecular chain is often broken too early, and meanwhile, the residual degradation product still pollutes the soil and is difficult to popularize and apply.

In recent years, with the continuous development of new material synthesis technology, the development of biodegradable mulching films is receiving wide attention from academia and industry. The biodegradable mulching film is degraded by microorganisms in soil under natural environment to generate non-toxic small molecules (CO)₂And H₂O), a plastic mulching film which does not cause harm to the ecological environment. The existing research shows that the biodegradable mulching film has the functions of warming, preserving soil moisture, inhibiting weeds and the like similar to the traditional PE mulching film, and can thoroughly solve the residual problem after the mulching film is used.

At present, the research on the biodegradable mulching film is mainly embodied in the development and utilization of novel materials, and the research on the degradation time of the mulching film is relatively less. Because different crops have different growth cycles and different requirements on the degradation time of the mulching film, the development of the mulching film with controllable dissolution time has important significance on the growth of the crops and the environmental protection.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the agricultural mulching film with controllable dissolving time and the preparation method thereof, the raw materials are natural, the process is simple, the prepared product has good heat preservation performance, water solubility, low cost, energy conservation and environmental protection; can be dissolved into the environment regularly and naturally, and products with controllable dissolving time of 45-80 days can be prepared respectively according to the requirement.

In order to achieve the purpose, the invention adopts the technical scheme that:

an agricultural mulching film with controllable dissolution time is prepared from the following components in parts by weight:

30-75 parts of natural amylose, 1-10 parts of carboxymethyl cellulose, 5-30 parts of glycerol, 10-30 parts of modified polyvinyl alcohol, 0.1-2 parts of diethylene glycol, 1-6 parts of dioleate, 0.1-2 parts of stearic acid, 0.1-1.5 parts of sodium benzoate, 0.1-5 parts of benzamide, 0.1-1.5 parts of titanium dioxide and 15-17 parts of water;

the natural amylose is cassava starch;

the modified polyvinyl alcohol is obtained by mixing and modifying 1-10 parts of polyvinyl alcohol 1799 and 1-20 parts of polyvinyl alcohol 1788;

the invention also aims to provide a preparation method of the agricultural mulching film with controllable dissolution time, which comprises the following steps:

(1) mixing materials: 30-75 parts of natural amylose, 1-10 parts of carboxymethyl cellulose, 5-30 parts of glycerol, 10-30 parts of modified polyvinyl alcohol, 0.1-2 parts of diethylene glycol, 1-6 parts of dioleate, 0.1-2 parts of stearic acid, 0.1-1.5 parts of sodium benzoate, 0.1-5 parts of benzamide, 0.1-1.5 parts of titanium dioxide and 15-17 parts of water, heating to 50-75 ℃ by a high-speed mixer, mixing at the rotation speed of 300r/min, and stirring for 20-45 min;

(2) extruding: adding the mixed material into an extruder through a feeding machine, and extruding and granulating by adopting a double-screw extruder with the length-diameter ratio of 48: 1;

(3) film blowing: blowing a film on the particles obtained in the step (2) by using a single-screw extruder with the length-diameter ratio of 36:1 to obtain a film with the thickness of 15 +/-2-25 +/-3 mu m;

the rotating speed of the feeding machine in the step (2) is 10-30r/min, the rotating speed of a screw of an extruder is 50-100r/min, and the working temperature of the extruder is 110-190 ℃;

the working temperature of the single-screw extruder in the step (3) is 110-.

The invention has the beneficial effects that:

(1) the raw materials are natural, the method is simple, the prepared product has good heat preservation performance and water solubility, the cost is low, and the energy is saved and the environment is protected;

(2) the film prepared by the method can be naturally dissolved in the environment, the adding proportion of the added starch and the proportion of the injection molding agent are adjusted according to the required dissolving time, and the product with controllable dissolving time in 45-80 days can be obtained.

Detailed Description

The present invention is further illustrated in detail by the following examples, which are provided only for illustrating the present invention and are not intended to limit the scope of the present invention.