High-weather-resistance weeding mulching film and preparation method thereof

Abstract

The invention discloses a high-weather-resistance weeding mulching film and a preparation method thereof. Comprising the following components in parts by weight: 100 parts of polyethylene resin or biodegradable resin, 0.1-3 parts of herbicide, 0.2-1 part of hindered amine light stabilizer, 0.1-0.5 part of ultraviolet light absorber, 0.1-1 part of antioxidant, 0.2-2 parts of hydrotalcite and 0.2-1 part of nano hexagonal boron nitride. The efficient adsorption performance of nano hexagonal boron nitride on carbon dioxide is utilized, forward reaction of CO3 < 2-> between hydrotalcite layers and acidic substances is promoted, chemical attack of acidic products such as herbicides on the hindered amine light stabilizer is blocked, and therefore the weather resistance of the weeding mulching film is remarkably improved, and the service life of the weeding mulching film is remarkably prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of film materials, and in particular relates to a highly weather-resistant weed control 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 temperature, suppressing weeds, and increasing crop yields, significantly contributing to increased agricultural production and harvests. At the same time, farmers are increasingly demanding functional agricultural mulch films that can remove weeds, sterilize, increase fertilizer, and improve soil quality. However, simply introducing herbicides and insecticides into mulch films often shortens their lifespan. This is because these pesticides often contain elements such as sulfur (S) and chlorine (Cl). 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 problems of short service life and premature rupture of current functional mulch films such as weed control mulch, and provides a weed control mulch film with simple preparation method, high weather resistance and industrializability and its preparation method.

[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 acidic products such as herbicides on hindered amine light stabilizers, thereby significantly improving the weather resistance and service life of the weed control film.

[0007] The highly weather-resistant weed control film of the present invention comprises, by weight, 100 parts of polyethylene resin or biodegradable resin, 0.1-3 parts of herbicide, 0.2-1 parts of hindered amine light stabilizer, 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.

[0008] Preferably, the composition comprises, by weight, 100 parts of biodegradable resin, 0.5 parts of herbicide, 0.3-0.5 parts of hindered amine light stabilizer, 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 is polybutylene adipate / terephthalate, poly(butylene terephthalate-co-succinate), polylactic acid or polycarbonate.

[0010] Preferably, the herbicide comprises one or more of glufosinate-ammonium, pendimethalin, acetochlor, atrazine, and bensulfuron-methyl.

[0011] 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.

[0012] Preferably, the ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, etc.

[0013] 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.

[0014] Preferably, the average secondary particle size of the hydrotalcite is 0.3-1 micron.

[0015] Preferably, the thickness of the nano hexagonal boron nitride sheet is 20-100 nanometers.

[0016] The present invention also provides a method for preparing the above-mentioned highly weather-resistant weed control film, comprising the following steps: mixing the components uniformly by high-speed stirring according to the proportion, and then sequentially extruding, granulating, drying and blow-molding to obtain the above-mentioned pesticide-resistant film.

[0017] The present invention also provides the use of the highly weather-resistant weed control film in preparing functional weed control film.

[0018] The beneficial effects of the present invention are as follows:

[0019] (1) The highly weather-resistant weed control film prepared by this formula, wherein the nano hexagonal boron nitride has a strong ability to absorb carbon dioxide, the CO3 between the herbicide acidic substance 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 the herbicide acidic substances, and then blocks the chemical attack of the herbicide acidic products on the hindered amine light stabilizer, thereby significantly improving the long-term weather resistance of the weed control film.

[0020] (2) The nano-sheet structure of the nano hexagonal boron nitride used in this formulation 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 mulch film.

[0021] (3) The nano-sheet structure of the nano hexagonal boron nitride used in this formula can load small molecules such as herbicides through physical adsorption, thereby achieving a slow and controlled release of the herbicide, further improving the utilization rate of the herbicide, and promoting the reduction and improvement of the efficiency of the herbicide.

[0022] (4) 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

[0023] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0024] Example 1:

[0025] The present invention will be further described below with reference to the embodiments, but the present invention is not limited thereto.

[0026] The hindered amine in the examples is T68, produced by Beijing Tiangang Auxiliary Co., Ltd. The herbicide is atrazine. 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, with a weight ratio of 1:2. The average secondary particle size of the hydrotalcite is 0.44 μm. The thickness of the nano-hexagonal boron nitride flakes is approximately 20 nm.

[0027] 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.

[0028] Table 1. Examples of the present invention and comparative examples, kg

[0029] Material Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Polyethylene resin 100 100 100 100 100 100 100 herbicide 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Hindered amines 0.5 0.5 0.4 0.3 0.5 0.5 0.5 UV absorbers 0.1 0.1 0.1 0.1 0.1 0.1 0.1 antioxidants 0.4 0.3 0.3 0.3 0.3 0.3 0.3 hydrotalcite 1 0.8 0.8 0.8 0.8 0.8 / Hexagonal Boron Nitride 0.5 0.5 0.5 0.5 0.5 / /

[0030] 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):

[0031] (1) Weigh polyethylene resin, herbicide, 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;

[0032] (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;

[0033] (3) The prepared pellets are blown into a film on a film blowing machine at a temperature of 150° C., with a film thickness of 10 μm, to obtain the highly weather-resistant weed control film of the present invention.

[0034] The performance of the mulch films of the examples and comparative examples was tested as follows: the mulch films were aged according to GB\T16422-2006. After 120 hours of aging, the tensile strength and elongation at break of the mulch films were monitored and tested according to GB\T1040.3-2006. The test results are shown in Table 2.

[0035] Table 2. Performance test results of the mulch films of the examples and comparative examples

[0036]

[0037]

Claims

1. A highly weather-resistant weed control film, characterized in that: The invention comprises, by weight, 100 parts of polyethylene resin or biodegradable resin, 0.1-3 parts of herbicide, 0.2-1 parts of hindered amine light stabilizer, 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 highly weather-resistant weed control film according to claim 1, characterized in that: The composition comprises, by weight, 100 parts of biodegradable resin, 0.5 parts of herbicide, 0.3-0.5 parts of hindered amine light stabilizer, 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 highly weather-resistant weed control film according to claim 1, characterized in that: The biodegradable resin is polybutylene adipate / terephthalate, poly(butylene terephthalate-co-succinate), polylactic acid or polycarbonate.

4. The highly weather-resistant weed control film according to claim 1, characterized in that: The herbicide comprises one or more of glufosinate-ammonium, pendimethalin, acetochlor, atrazine and bensulfuron-methyl.

5. The highly weather-resistant weed control film according to claim 1, characterized in that: 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. or the hindered amine light stabilizer with brand XT100 produced by BASF (China) Co., Ltd.

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

7. The highly weather-resistant weed control 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.

8. The highly weather-resistant weed control film according to claim 1, characterized in that: The average secondary particle size of the hydrotalcite is 0.3-1 micrometers; or the sheet thickness of the nano hexagonal boron nitride is 20-100 nanometers.

9. A method for preparing any one of claims 1 to 8 of the highly weather-resistant weed control film, 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 highly weather-resistant weed control film.

10. Use of any of the highly weather-resistant weed control films according to claims 1 to 8 in the preparation of functional weed control films.

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