Pesticide-tolerant mulching film and preparation method thereof

Abstract

The invention discloses a pesticide-tolerant mulching film and a preparation method thereof. The polyethylene / biodegradable plastic comprises the following components in parts by weight: 100 parts of polyethylene resin or biodegradable resin, 0.2-1 part of hindered amine, 0.1-0.5 part of an ultraviolet light absorber, 0.1-1 part of an antioxidant, 0.2-2 parts of hydrotalcite and 0.2-1 part of nano hexagonal boron nitride. According to the pesticide-tolerant mulching film prepared according to the formula, nano hexagonal boron nitride has very strong capability of adsorbing carbon dioxide, and carbon dioxide generated after reaction of pesticide acidic substances and CO3 < 2-> between hydrotalcite layers can be rapidly captured by nano hexagonal boron nitride, so that reaction consumption of the pesticide acidic substances is promoted; furthermore, chemical attack of pesticide acidic products on the hindered amine light stabilizer is blocked, so that the long-acting weather resistance of the mulching film in a composite pesticide environment is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of film materials, and particularly relates to a pesticide-resistant ground film and a preparation method thereof. Background Art

[0002] With the development of modern agricultural technology, agricultural mulch films have played a significant role in conserving soil moisture, increasing temperatures, suppressing weeds, and increasing crop yields, significantly contributing to increased agricultural production and harvests. At the same time, pesticides such as insecticides and fungicides, key inputs for ensuring healthy crop growth, often introduce compounds containing elements such as sulfur (S) and chlorine (Cl) into the farmland environment during their use. However, during natural degradation or photochemical reactions, these pesticides may generate salts and acidic oxidation products of S and Cl (such as sulfates, hydrochloric acid, and hypochlorous acid). These substances can react chemically with hindered amine light stabilizers (HALs) widely used in mulch films or their conversion products (including but not limited to NO radicals, N-OH derivatives, and NR alkylation products).

[0003] Specifically, HALs, as the core additive for the anti-aging properties of ground films, mainly delays the photo-oxidative degradation of polymer materials by capturing free radicals, decomposing peroxides and other mechanisms. However, acidic substances derived from pesticides will undergo acid-base neutralization or nucleophilic substitution reactions with HALs active groups (such as amino groups, hydroxyl groups, etc.), resulting in the destruction of the HALs molecular structure and the loss of its free radical capture ability. This chemical inactivation phenomenon will significantly weaken the weather resistance of the ground film, accelerate the photodegradation process of the ground film, and thus shorten its service life. This will not only cause the premature decline of the physical properties of the ground film (such as mechanical strength and light transmittance), but will also increase agricultural production costs due to frequent replacement of the ground film, while aggravating the problem of white pollution in farmland.

[0004] The service life of greenhouse film will also be affected by pesticides. Some literature reports use weakly alkaline hindered amines to reduce the reactivity of hindered amines with acidic substances; or use CO3 2- It can react with acidic substances to protect the activity of hindered amines, and hydrotalcite can absorb metal ions (such as Fe 3+ 、Cu 2+ ) and thus inhibit the oxidative inactivation of its catalytic HALs. However, since the greenhouse film is covered on the crops sprayed with pesticides and adjuvants such as drip agents are added, no acidic droplets will form on the surface of the film, and the CO3 between the hydrotalcite layers will 2- The products of the reaction with acidic substances will disperse in time, promoting the forward reaction. However, when the ground film is laid on the ground, it is easy for small droplets of acidic substances to form on the film surface after spraying pesticides. 2-The product water and carbon dioxide dissolved in it after the reaction with the acidic substance remain on the membrane surface, which may lead to a reverse reaction. The acidic substance still has a high probability of reacting with the hindered amine, resulting in poor weather resistance of the ground membrane. Summary of the Invention

[0005] The present invention aims to solve the key problem that current mulch films and other products have poor tolerance to pesticides and are prone to premature rupture, and provides a mulch film with a simple preparation method, high tolerance to pesticides, and industrializability, and a preparation method thereof.

[0006] Principle: Utilize the high efficiency adsorption of carbon dioxide by nano hexagonal boron nitride to promote the adsorption of CO3 between hydrotalcite layers. 2- The forward reaction with acidic substances blocks the chemical attack of pesticide acidic products on hindered amine light stabilizers, thereby significantly improving the long-term weather resistance of the mulch film in a complex pesticide environment.

[0007] The pesticide-resistant mulch film of the present invention comprises, by weight, 100 parts of polyethylene resin or biodegradable resin, 0.2-1 part of hindered amine, 0.1-0.5 part of ultraviolet absorber, 0.1-1 part of antioxidant, 0.2-2 parts of hydrotalcite and 0.2-1 part of nano hexagonal boron nitride.

[0008] Preferably, the composition comprises, by weight, 100 parts of polyethylene resin, 0.3-0.5 parts of hindered amine, 0.1 parts of ultraviolet absorber, 0.3-0.4 parts of antioxidant, 0.8-1 parts of hydrotalcite and 0.5 parts of nano hexagonal boron nitride.

[0009] Preferably, the biodegradable resin can be polybutylene adipate / terephthalate, poly(butylene terephthalate-co-succinate), polylactic acid, polycarbonate and other biodegradable resins.

[0010] Preferably, the hindered amine (light stabilizer) is a weakly basic hindered amine, such as the hindered amine light stabilizers with brands T66, T68, and T69 produced by Beijing Tiangang Auxiliary Co., Ltd., and the hindered amine light stabilizer with brand XT100 produced by BASF (China) Co., Ltd.

[0011] Preferably, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, etc.

[0012] Preferably, the antioxidant is one or a combination of 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tris[2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-4-methyl-6-tert-butylphenol]-cyanurate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and tris(2,4-di-tert-butylphenyl)phosphite.

[0013] Preferably, the average secondary particle size of the hydrotalcite is 0.3-1 micron.

[0014] Preferably, the nano hexagonal boron nitride has a sheet thickness of 20-100 nanometers.

[0015] The present invention also provides a method for preparing the above-mentioned pesticide-resistant mulch film, comprising the following steps: mixing the components uniformly by high-speed stirring according to the proportion, and then extruding, granulating, drying and blow-molding in sequence to obtain the pesticide-resistant mulch film.

[0016] The present invention also provides the above-mentioned pesticide-resistant mulch film for use in preparing agricultural pesticide-resistant mulch film.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) The pesticide-resistant mulch prepared by this formula has a strong ability to absorb carbon dioxide, and the CO3 between the pesticide acid and the hydrotalcite layer 2- The carbon dioxide generated after the reaction can be quickly captured by nano hexagonal boron nitride, which promotes the reaction consumption of pesticide acidic substances, and then blocks the chemical attack of pesticide acidic products on hindered amine light stabilizers, thereby significantly improving the long-term weather resistance of the mulch film in a complex pesticide environment.

[0019] (2) The nano-sheet structure of the nano hexagonal boron nitride used in this formula can load small molecules such as hindered amine light stabilizers, antioxidants, and ultraviolet absorbers through physical adsorption, slowing down the migration and diffusion of small molecules and further improving the weather resistance of the ground film.

[0020] (3) The nano hexagonal boron nitride used in this formula has good dispersibility in biodegradable resins such as polyethylene resin, polybutylene adipate / terephthalate, and poly(butylene terephthalate-co-succinate). The preparation method is simple and the industrialization prospect is broad. DETAILED DESCRIPTION

[0021] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0022] Example 1:

[0023] The present invention will be further described below with reference to the embodiments, but the present invention is not limited thereto.

[0024] The hindered amine used in the examples is T68, manufactured by Beijing Tiangang Auxiliary Agent Co., Ltd. The UV absorber is 2-hydroxy-4-octyloxybenzophenone. The antioxidant is a combination of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite, in a mass ratio of 1:2. The average secondary particle size of the hydrotalcite is 0.44 μm. The nano-hexagonal boron nitride sheet thickness is approximately 20 nm.

[0025] The following table shows the examples and comparative examples. The differences between the examples and comparative examples are that, in comparative example 1, hindered amine T-68 is replaced with ordinary hindered amine 944 based on example 2; in comparative example 2, nano hexagonal boron nitride is removed based on example 2; and in comparative example 3, hydrotalcite and nano hexagonal boron nitride are removed based on example 2.

[0026] Table 1. Examples of the present invention and comparative examples, kg.

[0027]

[0028]

[0029] The preparation methods of the mulch films of the embodiments and comparative examples are as follows (if a component is not present, it is omitted):

[0030] (1) Weigh polyethylene resin, hindered amine, ultraviolet absorber, antioxidant, hydrotalcite, and nano hexagonal boron nitride in proportion, place in a high-speed blender and mix for 5 minutes, then discharge the materials;

[0031] (2) Extruding the mixed material into pellets in a twin-screw extruder at a temperature of 110-150° C., and cutting into pellets using a plastic pelletizer;

[0032] (3) The prepared pellets are blown into films at 150° C. on a film blowing machine with a film thickness of 10 μm to obtain the pesticide-resistant ground film of the present invention.

[0033] The performance of the mulch films from the examples and comparative examples was tested as follows: the films were soaked in 0.1M sulfurous acid for 24 hours and then aged according to GB\T16422-2006. After aging for 120 hours, the tensile strength and elongation at break of the films were monitored and tested according to GB\T1040.3-2006. The test results are shown in Table 2.

[0034] Table 2. Performance test results of the mulch films of the examples and comparative examples.

[0035]

[0036]

Claims

1. A pesticide-resistant mulch film, characterized in that: The invention comprises, by weight, 100 parts of polyethylene resin or biodegradable resin, 0.2-1 parts of hindered amine, 0.1-0.5 parts of ultraviolet absorber, 0.1-1 parts of antioxidant, 0.2-2 parts of hydrotalcite and 0.2-1 parts of nano hexagonal boron nitride.

2. The pesticide-resistant mulch film according to claim 1, characterized in that: The composition comprises, by weight, 100 parts of polyethylene resin, 0.3-0.5 parts of hindered amine, 0.1 parts of ultraviolet absorber, 0.3-0.4 parts of antioxidant, 0.8-1 parts of hydrotalcite and 0.5 parts of nano hexagonal boron nitride.

3. The pesticide-resistant mulch film according to claim 1, characterized in that: The biodegradable resin is polybutylene adipate / terephthalate, poly(terephthalate-co-butylene succinate), polylactic acid or polycarbonate.

4. The pesticide-resistant mulch film according to claim 1, characterized in that: The hindered amine is a weakly basic hindered amine, such as the hindered amine light stabilizers with brands T66, T68, and T69 produced by Beijing Tiangang Auxiliary Co., Ltd. and the hindered amine light stabilizer with brand XT100 produced by BASF (China) Co., Ltd.

5. The pesticide-resistant mulch film according to claim 1, characterized in that: The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

6. The pesticide-resistant mulch film according to claim 1, characterized in that: The antioxidant is one or a combination of 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tris[2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-4-methyl-6-tert-butylphenol]-cyanurate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and tris(2,4-di-tert-butylphenyl) phosphite.

7. The pesticide-resistant mulch film according to claim 1, characterized in that: The average secondary particle size of the hydrotalcite is 0.3-1 micron.

8. The pesticide-resistant mulch film according to claim 1, characterized in that: The nano hexagonal boron nitride has a sheet thickness of 20-100 nanometers.

9. A method for preparing the pesticide-resistant mulch film according to any one of claims 1 to 8, characterized in that: The following steps are involved: According to the proportion, the components are uniformly mixed by high-speed stirring, and then extruded, granulated, dried and blown in sequence to obtain the pesticide-resistant mulch film.

10. The pesticide-resistant mulch film according to any one of claims 1 to 8 is used for preparing agricultural pesticide-resistant mulch film.

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