阅读说明：本技术 一种可降解农用薄膜和制备方法 (Degradable agricultural film and preparation method thereof ) 是由 郎宝龙 隋英丹 李炳岐 于 2020-06-03 设计创作，主要内容包括：本发明提供一种可降解农用薄膜的制备方法和农用薄膜,制备方法包括：将原料混合得到混合物；将混合物放入双螺杆挤出机中挤出胶体；将胶体在流延机上流延成薄膜；将薄膜经过干燥、冷却得到可降解农用薄膜；原料包括：热塑性淀粉改性聚氯乙烯100-120重量份；无机非金属5-15重量份；增塑剂0.8-2重量份。通过热塑性淀粉改性聚氯乙烯、无机非金属材料、增塑剂作为原料,挤出成型后经流延成薄膜,薄膜可降解,降解后无污染残留,降解后可调节土壤,具有阻隔红外线辐射、具有吸附肥料异味的特殊功能；透气性强透水性高,二氧化碳气体的通过性高,可加强农作物的呼吸作用。(The invention provides a preparation method of a degradable agricultural film and the agricultural film, wherein the preparation method comprises the following steps: mixing the raw materials to obtain a mixture; putting the mixture into a double-screw extruder to extrude the colloid; casting the colloid on a casting machine to form a film; drying and cooling the film to obtain a degradable agricultural film; the raw materials comprise: 100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride; 5-15 parts of inorganic nonmetal; 0.8-2 parts of plasticizer. The thermoplastic starch modified polyvinyl chloride, the inorganic non-metallic material and the plasticizer are used as raw materials, and the raw materials are extruded and molded to form a film through casting, the film is degradable, no pollution residue is left after degradation, the soil can be adjusted after degradation, and the film has the special functions of blocking infrared radiation and adsorbing fertilizer peculiar smell; strong air permeability and high water permeability, and the permeability of carbon dioxide gas is high, so that the respiration of crops can be enhanced.)

1. A method for preparing a degradable agricultural film, which is characterized by comprising the following steps:

mixing the raw materials to obtain a mixture;

putting the mixture into a double-screw extruder to extrude colloid;

casting the colloid into a film on a casting machine;

drying and cooling the film to obtain a degradable agricultural film;

wherein the raw materials comprise:

100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride;

5-15 parts of inorganic nonmetal;

0.8-2 parts of plasticizer.

2. The method of claim 1, wherein the feedstock further comprises:

0.2-2 parts of lubricant;

0.2 to 0.6 weight portion of nucleating agent.

3. The method for preparing the thermoplastic starch modified polyvinyl chloride according to claim 1, wherein the method for preparing the thermoplastic starch modified polyvinyl chloride comprises the following steps:

evenly mixing the paraffin, the polyvinyl chloride master batch and the low-density polyethylene to obtain a mixture;

adding corn starch and a stabilizer into the mixture, and reacting at the temperature of below 50 ℃ and the pH of 4.5-6.5 to obtain the thermoplastic starch modified polyvinyl chloride.

4. The method of claim 1, wherein the inorganic nonmetal comprises:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

5. The method of claim 1 or 4, wherein the inorganic nonmetal comprises: SiO 2₂60-80％、Al₂O₃10-30％、K₂O 4-8％、Na₂O 0.5-1.5％、CaO 0-1％、MgO 0-1％。

6. The method according to claim 1, wherein the inorganic nonmetal is loaded with rare earth ions.

7. A degradable agricultural film, comprising:

100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride;

5-15 parts of inorganic nonmetal;

1-2 parts of plasticizer.

8. The degradable agricultural film of claim 7, further comprising:

0.2-2 parts of lubricant;

0.2 to 0.6 weight portion of nucleating agent.

9. The degradable agricultural film of claim 7, wherein the inorganic nonmetal comprises:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

10. The degradable agricultural film of claim 7, wherein the inorganic nonmetal is loaded with rare earth ions.

Technical Field

The invention relates to the field of agricultural films, in particular to a degradable agricultural film and a preparation method thereof.

Background

Disclosure of Invention

In view of the above, the invention provides a degradable agricultural film and a preparation method thereof, which are used for solving the problems that the existing film is not easy to degrade, is easy to generate pollution and is poor in air permeability.

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

in a first aspect, a method for preparing a degradable agricultural film according to an embodiment of the present invention includes:

mixing the raw materials to obtain a mixture;

putting the mixture into a double-screw extruder to extrude colloid;

casting the colloid into a film on a casting machine;

drying and cooling the film to obtain a degradable agricultural film;

wherein the raw materials comprise:

100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride;

5-15 parts of inorganic nonmetal;

0.8-2 parts of plasticizer.

Wherein, the raw materials also include:

0.2-2 parts of lubricant;

0.2 to 0.6 weight portion of nucleating agent.

The preparation method of the thermoplastic starch modified polyvinyl chloride comprises the following steps:

evenly mixing the paraffin, the polyvinyl chloride master batch and the low-density polyethylene to obtain a mixture;

adding corn starch and a stabilizer into the mixture, and reacting at the temperature of below 50 ℃ and the pH of 4.5-6.5 to obtain the thermoplastic starch modified polyvinyl chloride.

Wherein the inorganic nonmetal comprises:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

Wherein the inorganic nonmetal comprises: SiO 2₂60-80％、Al₂O₃10-30％、K₂O 4-8％、Na₂O 0.5-1.5％、CaO 0-1％、MgO 0-1％。

Wherein the inorganic nonmetal is loaded with rare earth ions.

In a second aspect, a degradable agricultural film according to an embodiment of the present invention includes:

100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride;

5-15 parts of inorganic nonmetal;

1-2 parts of plasticizer.

Wherein, still include:

0.2-2 parts of lubricant;

0.2 to 0.6 weight portion of nucleating agent.

Wherein the inorganic nonmetal comprises:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

Wherein the inorganic nonmetal is loaded with rare earth ions.

The technical scheme of the invention has the following beneficial effects:

according to the preparation method of the degradable agricultural film, the raw materials are mixed to obtain a mixture; putting the mixture into a double-screw extruder to extrude colloid; casting the colloid into a film on a casting machine; drying and cooling the film to obtain a degradable agricultural film; the raw materials comprise: 100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride; 8-15 parts of inorganic nonmetal; 0.8-2 parts of plasticizer. In the preparation process, thermoplastic starch modified polyvinyl chloride, inorganic non-metallic materials and plasticizer are used as raw materials, and the raw materials are extruded and molded to form a film through casting, wherein the film can be widely used for agricultural mulching films and agricultural greenhouse films, is degradable and has no pollution residue after degradation; the inorganic nonmetal has outstanding reinforcement and better heat resistance, and the nonmetal material can catalyze and degrade the film, thereby solving the problem that the traditional plastic film is not degradable or has residue after degradation to cause white pollution, and the soil can be adjusted after degradation; compared with other agricultural films, the film has the advantages of infrared radiation blocking, outstanding heat preservation and special function of absorbing fertilizer peculiar smell; compared with other films, the film has strong air permeability and high water permeability, has high carbon dioxide gas permeability, can strengthen the respiration of crops, and is beneficial to the growth of fruits and vegetables.

Drawings

FIG. 1 is a schematic flow chart of a preparation method of an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

The method for preparing the degradable agricultural film according to the embodiment of the present invention is described in detail below.

As shown in fig. 1, a method for preparing a degradable agricultural film according to an embodiment of the present invention includes:

step S1, mixing the raw materials to obtain a mixture;

step S2, putting the mixture into a double-screw extruder to extrude colloid;

step S3, casting the colloid into a film on a casting machine;

step S4, drying and cooling the film to obtain a degradable agricultural film;

wherein the raw materials comprise:

100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride;

5-15 parts of inorganic nonmetal;

0.8-2 parts of plasticizer.

That is, in the above preparation process, the raw materials are uniformly mixed according to a certain proportion, and a certain solvent, such as water, can be added; putting the mixture into a double-screw extruder to extrude colloid; casting the colloid into a film on a casting machine, for example, casting the colloid into a film on a drum casting machine; and finally, drying, cooling, cutting edges and rolling to obtain the degradable agricultural film, for example, the degradable agricultural film can be extruded, cast and cooled, measured in thickness, pulled and cut, flattened to remove static electricity and rolled to obtain a rolled film, and the thickness, width and length of the film can be cut according to actual requirements. The raw materials can be added into a screw rod of an extruder barrel to be mixed and stirred for 20-30min to extrude colloid, the temperature is controlled at 180-200 ℃, and the temperatures of four zones of a double-screw extruder can be respectively as follows: the feeding section is 100 ℃, the compression section is 130 ℃, the metering section is 140 ℃, the machine head section is 160 ℃, the screw rotating speed is 35r/min, and the transparent colloid is extruded and then put on a drum casting machine for casting, film forming and cooling. The casting machine can be heated by adopting an oil bath of a mold temperature controller, the surface temperature of the casting roller is controlled at 52 ℃, the gap between the knife edge of the casting machine and the casting roller is adjusted to be 0.35mm thick, and the rotating speed of the casting roller is controlled at 3 m/min.

In the preparation process, thermoplastic starch modified polyvinyl chloride, inorganic non-metallic materials and a plasticizer are used as raw materials, the inorganic non-metallic materials can be nanoparticles, and the inorganic non-metallic materials are extruded and molded to form a film through casting, the film can be widely used for agricultural mulching films and agricultural greenhouse films, and is degradable and free of pollution residue after degradation; the inorganic nonmetal has outstanding reinforcement and better heat resistance, and the nonmetal material can catalyze and degrade the film, thereby solving the problem that the traditional plastic film is not degradable or has residue after degradation to cause white pollution, and the soil can be adjusted after degradation; compared with other agricultural films, the film has the advantages of infrared radiation blocking, outstanding heat preservation and special function of absorbing fertilizer peculiar smell; compared with other films, the film has strong air permeability and high water permeability, has high carbon dioxide gas permeability, can strengthen the respiration of crops, and is beneficial to the growth of fruits and vegetables.

In some embodiments of the invention, the feedstock may further comprise: 0.2-2 parts of lubricant and 0.2-0.6 part of nucleating agent, wherein the lubricant is favorable for extrusion and tape casting, and the nucleating agent is favorable for foaming and film forming. The lubricant can be paraffin, the nucleating agent can be talcum powder, and the plasticizer can be trinonyl citrate, so that the environment-friendly effect is realized.

In other embodiments, the method for preparing thermoplastic starch modified polyvinyl chloride may comprise:

evenly mixing the paraffin, the polyvinyl chloride master batch and the low-density polyethylene to obtain a mixture;

adding corn starch and a stabilizer into the mixture, reacting at the temperature of below 50 ℃ and the pH of 4.5-6.5 to obtain the thermoplastic starch modified polyvinyl chloride, and slowly feeding or stopping feeding when the temperature is too high. The stabilizing agent can comprise sorbitol, the stabilizing agent can comprise sorbitol and salicylic acid rare earth, the reaction temperature can be 35-50 ℃, and the reaction is carried out under the condition that the PH is 4.5-6.5, so that the thermoplastic starch modified polyvinyl chloride is obtained, the performance of the polyvinyl chloride can be improved through the starch, the degradation is facilitated under the condition that certain high strength is ensured, and the air permeability is better.

In embodiments of the invention, the inorganic non-metals may include:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

For example, the inorganic nonmetal can comprise illite and kaolin, the illite is rich in active potassium and has a nitrogen fixation function, and the plastic film is degraded to facilitate plant absorption and can be used as an agricultural fertilizer and a soil conditioner; the illite can release negative ions, has outstanding reinforcing property and better heat resistance, can catalyze and degrade the plastic film, solves the problem that the traditional plastic film is not degradable or has residues after degradation to cause white pollution, and can adjust soil after degradation; the film also has the advantages of infrared radiation blocking, peculiar smell adsorption, outstanding heat preservation and the like.

In some embodiments, the inorganic non-metals may include: SiO 2₂60-80％、Al₂O₃10-20％、K₂O4-8％、Na₂0.5 to 1.5 percent of O, 0 to 1 percent of CaO and 0 to 1 percent of MgO. The performance of the film can be improved, so that the film has certain strength and better air permeability. Can be prepared by the above illite; and/or at least one of quartz, kaolin, limestone, potassium feldspar, albite, micanite and montmorillonite is subjected to coordination regulation, so that SiO in the inorganic nonmetal is obtained₂、Al₂O₃、K₂O、Na₂The contents of O, CaO and MgO are in the above-mentioned ranges. Further, SiO may be added as required₂、Al₂O₃、K₂O、Na₂One or more of O, CaO and MgOMultiple, to adjust the content of the corresponding components.

Optionally, the inorganic nonmetal is loaded with rare earth ions, for example, illite can be loaded with rare earth ions, illite, kaolin and limestone can be loaded with rare earth ions respectively, and the rare earth ions can sterilize and disinfect, release negative ions, facilitate odor adsorption and catalyze and degrade the plastic film. Wherein, the content of the rare earth ions in the inorganic nonmetal can be more than or equal to 1000 μ g/g, and the rare earth ions can include: scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, inorganic nonmetal with particle size of 10-50 μm is beneficial to uniformly dispersing in the film. The functionality of the inorganic non-metallic material includes: the ion generation amount is more than or equal to 1000ions/cm³(1Kg of material at 1m³Space internal measurement), the peculiar smell adsorption efficiency is more than or equal to 80 percent, the peculiar smell adsorption durability is more than or equal to 70 percent, the degradation time meets the national standard, and the infrared ray blocking rate is more than or equal to 50 percent.

The embodiment of the invention provides a degradable agricultural film.

The degradable agricultural film comprises: 100 parts of thermoplastic starch modified polyvinyl chloride and 120 parts of thermoplastic starch modified polyvinyl chloride; 5-15 parts of inorganic nonmetal; 1-2 parts of plasticizer.

In the preparation process, thermoplastic starch modified polyvinyl chloride, inorganic non-metallic materials and plasticizer are used as raw materials, and the raw materials are extruded and molded to form a film through casting, wherein the film can be widely used for agricultural mulching films and agricultural greenhouse films, is degradable and has no pollution residue after degradation; the inorganic nonmetal has outstanding reinforcement and better heat resistance, and the nonmetal material can catalyze and degrade the film, thereby solving the problem that the traditional plastic film is not degradable or has residue after degradation to cause white pollution, and the soil can be adjusted after degradation; compared with other agricultural films, the film has the advantages of infrared radiation blocking, outstanding heat preservation and special function of absorbing fertilizer peculiar smell; compared with other films, the film has strong air permeability and high water permeability, has high carbon dioxide gas permeability, can strengthen the respiration of crops, and is beneficial to the growth of fruits and vegetables.

In some embodiments, the degradable agricultural film may further include: 0.2 to 2 parts of lubricant and 0.2 to 0.6 part of nucleating agent. The lubricant is beneficial to extrusion and flow casting in the process of processing the film, and the nucleating agent is beneficial to foaming and film forming.

In an embodiment of the present invention, the inorganic nonmetal may include:

illite; and/or

At least one of quartz, kaolin, limestone, potassium feldspar, albite, micaceous stone and montmorillonite.

For example, the inorganic nonmetal can comprise illite and kaolin, negative ions can be released through the illite, the illite has outstanding reinforcing property and better heat resistance, the illite can catalyze and degrade the plastic film, the problem that the traditional plastic film is not degradable or remains after degradation to cause white pollution is solved, and the soil can be adjusted after degradation; the film also has the advantages of infrared radiation blocking, peculiar smell adsorption, outstanding heat preservation and the like. In some embodiments, the inorganic non-metals may include: SiO 2₂60-80％、Al₂O₃10-20％、K₂O 4-8％、Na₂0.5 to 1.5 percent of O, 0 to 1 percent of CaO and 78 to 1 percent of MgO 0. The performance of the film can be improved, so that the film has certain strength and better air permeability. Can be prepared by the above illite; and/or at least one of quartz, kaolin, limestone, potassium feldspar, albite, micanite and montmorillonite is subjected to coordination regulation, so that SiO in the inorganic nonmetal is obtained₂、Al₂O₃、K₂O、Na₂The contents of O, CaO and MgO are in the above-mentioned ranges. Further, SiO may be added as required₂、Al₂O₃、K₂O、Na₂One or more of O, CaO and MgO to adjust the contents of the respective components.

Optionally, the inorganic nonmetal has rare earth ions loaded therein. For example, rare earth ions can be loaded on illite, kaolin and limestone respectively, sterilization and disinfection can be realized through the rare earth ions, negative ions can be released, peculiar smell adsorption can be facilitated, and the plastic film can be degraded in a catalytic mode. Wherein the content of rare earth ions in the inorganic nonmetal is greater than or equal toAt 1000. mu.g/g, the rare earth ions may include: scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, inorganic nonmetal with particle size of 10-50 μm is beneficial to uniformly dispersing in the film. The functionality of the inorganic non-metallic material includes: the ion generation amount is more than or equal to 1000ions/cm³(1Kg of material at 1m³Space internal measurement), the peculiar smell adsorption efficiency is more than or equal to 80 percent, the peculiar smell adsorption durability is more than or equal to 70 percent, the degradation time meets the national standard, and the infrared ray blocking rate is more than or equal to 50 percent.

The invention is further illustrated by the following specific examples.