Nano insect-proof net as well as preparation method and application thereof

Abstract

The invention relates to the technical field of nanometer insect-proof nets, in particular to a nanometer insect-proof net and a preparation method and application thereof.The preparation method comprises the steps that white oil and nanometer silicon dioxide are mixed to obtain suspension liquid, dried linear low-density polyethylene and the suspension liquid are mixed and melted to obtain nanometer master batches, and the nanometer master batches are mixed and melted to obtain the nanometer insect-proof net. The preparation method comprises the following steps: premixing nano master batch and weather-resistant master batch, mixing with high-density polyethylene to obtain a blended material, melting, drawing, stretching and rolling to obtain fiber yarns, straightening and dividing the fiber yarns, and weaving into a net through a warp knitting machine and a weaving machine; according to the nanometer insect-proof net prepared by the preparation method provided by the invention, the mesh size is precisely designed, and the ventilation rate and the light transmission of the insect-proof net are remarkably improved while high-efficiency blocking of small-size pests is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of nano insect-proof nets, and in particular to a nano insect-proof net, a preparation method thereof and applications thereof. Background Art

[0002] Insect-proof nets are agricultural protective products used to prevent pests from invading crop planting areas and protect crops from pests. They are usually made of a mesh with a certain aperture. There are many small mesh holes evenly distributed on the mesh. The size of the mesh holes varies depending on the type of pests to be controlled. Currently, the silk insect-proof nets on the market are generally conventional insect-proof nets with thicker wire diameters. As the mesh aperture decreases, the ventilation rate decreases. While preventing and controlling small pests, it is difficult to overcome the shortcomings of slow heat dissipation, poor moisture removal, and poor light transmission. Summary of the Invention

[0003] The main purpose of the present invention is to provide a preparation method of a nano insect-proof net and its application to solve the problems raised in the above background technology.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing a nano masterbatch comprises the following steps: S1, hydrophobic nano-silica produced by the vapor phase method was selected and dried at 80°C for 2 hours in advance, and linear low-density polyethylene was dried at 80°C for 4 hours; S2, adding white oil to the nano-silica and stirring at a stirring speed of 2000-3000 rpm for 30 minutes to form a uniform suspension; S3, mixing and melting the dried linear low-density polyethylene with the suspension at a rotation speed of 200-250 rpm, extruding, cooling and granulating the melt-blended material to obtain nano masterbatch.

[0005] Furthermore, the white oil content in the nano masterbatch is 0.5-2wt%, the nano silicon dioxide content is 1-5wt%, and the linear low-density polyethylene content is 93-98.5wt%.

[0006] A method for preparing a nano insect-proof net comprises the following steps: The present invention uses the nano masterbatch prepared by the above-mentioned method for preparing the nano masterbatch; S1, drying high-density polyethylene at 80°C for 4 hours, premixing the nano masterbatch with the weathering masterbatch at a rotation speed of 500-800 rpm for 10-15 minutes; S2, mixing high-density polyethylene, pre-mixed nano masterbatch and weather-resistant masterbatch to obtain a blend, and adding the blend to an extruder to obtain fiber filaments through melting, drawing, stretching and winding; S3, straightening and dividing the fiber filaments into discs, and weaving them into a net through a warp knitting machine and a braiding machine.

[0007] Furthermore, the content of high-density polyethylene in the blend is 92-96 wt %, the content of the nano masterbatch is 2-5 wt %, and the content of the weather-resistant masterbatch is 2-3 wt %.

[0008] Furthermore, the grade of the high-density polyethylene is PE5000S.

[0009] Furthermore, the temperatures of the blend in the extruder are 150°C, 165°C, 175°C, 185°C, 190°C, 195°C, 185°C, 190°C, and 185°C, respectively.

[0010] The present invention provides a nano insect-proof net prepared by the preparation method of the nano insect-proof net.

[0011] Furthermore, the diameter of the nano insect-proof mesh is 0.16-0.18 mm.

[0012] Furthermore, the mesh of the nano-insect-proof net is square, and the mesh size is 0.5mm*0.5mm-0.85mm*0.85mm.

[0013] The present invention provides application of the nano insect-proof net in agricultural pest control.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This application uses the synergistic effect of nano-silica and linear low-density polyethylene, combined with the precise design of the mesh size, to significantly improve the ventilation rate and light transmittance of the insect-proof net while maintaining high efficiency in blocking small-sized pests. This application uses the physical damage mechanism of nano-silica to directly act on pests, avoiding the risk of resistance to chemical pesticides; This application uses a premixing process of white oil and nano-silica, combined with segmented temperature control of the extruder, to ensure that nano-silica is evenly dispersed in the polyethylene matrix; This application can effectively resist UV aging and increase service life by adding weather-resistant masterbatch. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of an indoor test of the nano-silica insect-proof net of the present invention against common giant thrips; Figure 2 This is a data chart showing the indoor insect repellent effect of the nano-silica insect-proof net of the present invention; Figure 3 This is a data graph showing the field barrier effect of different insect-proof nets of the present invention on common giant thrips; Figure 4 This is a data diagram showing the effects of different insect-proof nets on light intensity. Figure 5 This is a data diagram showing the effect of different insect-proof nets on wind speed according to the present invention; Figure 6 This is a data diagram showing the effect of different insect-proof nets on humidity in the present invention; Figure 7 This is a data diagram showing the effects of different insect-proof nets on temperature in the present invention.

[0016] Reference numerals: 1. Cowpea; 2. Nano-insect net; 3. Adult thrips; 4. High-density insect net. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] Preparation Example 1 The nano-silica, linear low-density polyethylene, white oil, high-density polyethylene, nano-masterbatch, and weather-resistant masterbatch in this embodiment are all measured in wt% by mass; Step 1: Select hydrophobic nano-silica produced by the vapor phase method and pre-dry it at 80°C for 2 hours, and dry 96wt% linear low-density polyethylene at 80°C for 4 hours; Step 2: Add 1 wt% white oil to 3 wt% nano-silica and stir at a stirring speed of 200 rpm for 30 minutes to form a uniform suspension; Step 3: Mixing and melting the dried linear low-density polyethylene and the suspension at a speed of 200 rpm, extruding, cooling and granulating the melt-blended material to obtain a nano masterbatch; Step 4: Weigh 94wt% of high-density polyethylene (PE5000S) and dry it at 80°C for 4h, weigh 3wt% of nano masterbatch and 3wt% of weathering masterbatch and premix them at a speed of 600rpm for 12min. Step 5: High-density polyethylene, pre-mixed nano masterbatch and weather-resistant masterbatch are mixed to obtain a blend, and then added to the extruder. The extruder has 9 sections, namely, zone 1 feeding section, zone 2 compression section, zone 3 melting section, zone 4 mixing section, zone 5 mixing section, zone 6 homogenization section, zone 7 exhaust section, zone 8 metering section and zone 9 die head insulation section. The temperature ranges of each section are 140-160℃, 160-170℃, 17 0-180℃, 180-190℃, 185-195℃, 190-200℃, 180-190℃, 185-195℃, 180-190℃. The temperature of each section of the blend in the extruder is 150℃, 165℃, 175℃, 185℃, 190℃, 195℃, 185℃, 190℃, 185℃. The fiber is made into filaments through melting, drawing, stretching, winding and other processes. Step 6: The fiber filaments are straightened and divided into discs, and then woven into a net using a warp knitting machine and a weaving machine. The obtained nano insect-proof net has a wire diameter of 0.17 mm, a square mesh, and a mesh size of 0.5 mm*0.5 mm.

[0019] Comparative Preparation Example 1 The rest of the preparation method of this comparative example is the same as that of Preparation Example 1, except that nano-silicon dioxide is not added to the nano-masterbatch during the preparation.

[0020] Comparative Preparation Example 2 The rest of the preparation method of this comparative example is the same as that of Preparation Example 1, except that 0.5 wt % of nano-silicon dioxide is added during the preparation of the nano-masterbatch.

[0021] Comparative Preparation Example 3 The rest of the preparation method of this comparative example is the same as that of Preparation Example 1, except that 10 wt % of nano-silicon dioxide is added during the preparation of the nano-masterbatch.

[0022] Examples 1-5 all use the insect-proof functional masterbatch prepared in Preparation Example 1 as raw material, and the difference lies in the different process parameters of each step, as shown in the table below.

[0023] Table 1 Process parameters of Examples 1-5

[0024] Comparative Examples 1-3 are all based on Example 1, except that the nano masterbatch is different. Specifically: Comparative Example 1 uses the nano masterbatch prepared in Comparative Preparation Example 1; Comparative Example 2 uses the nano masterbatch prepared in Comparative Preparation Example 2; Comparative Example 3 uses the nano masterbatch prepared in Comparative Preparation Example 3; [Indoor insect repellent test] The nano-silica insect-proof net prepared in Example 1 was used. The nano-silica insect-proof net cage with a cage specification of 0.5m*0.5m was placed in a high-density large insect-proof net cage with a size of 100 mesh and 1m*1m. 100 common large thrips adults were taken and released into the gap between the nano-insect-proof net and the high-density insect-proof net. Two fresh and intact lentils weighing about 10 grams were placed in the nano-insect-proof net. After one day, the number of thrips adults in the nano-insect-proof net was counted to determine the barrier effect of the nano-insect-proof net on thrips adults. The deworming rate is: .

[0025] The test results are shown in the following table: Table 2 Indoor insect repellent effect test results

[0026] By counting the number of thrips in the nano-silica insect-proof net cage, the insect repellent rate of the nano-silica insect-proof net was determined. After one month of testing, the insect repellent effect of the nano-silica insect-proof net can be maintained at more than 60wt%, and the insect repellent effect can be maintained for more than 1 month. The nano-insect-proof net cage with a pore size of 0.5mm*0.5mm has the effect of repelling and blocking bean thrips, and has a certain lasting effect. During the test period, the nano-silica insect-proof net cage can repel and block the adult bean thrips.

[0027] [Field insect control trial] Test materials The 20-mesh nano-silica insect-proof net prepared in Example 3 was used for the test. The 20-mesh nano-silica insect-proof net had a horizontal diameter of 0.85 mm, a vertical diameter of 0.85 mm, and a wire diameter of 0.16 mm.

[0028] 1.1 Field thrips population survey method A five-point survey method was used, with five flowers taken at each point, for a total of 25 flowers surveyed each time. The flowers were placed in sealed bags and brought back indoors to remove the three layers of flowers to investigate the number of thrips. No chemical pesticides were used during the entire growing period of cowpea.

[0029] 1.2 Determination of the effect of covering with nano-insect screen on light intensity and ventilation The light intensity and wind speed in the nano-insect-proof net shed and in the open field were measured using a light meter and anemometer. The light intensity was measured in the insect-proof net shed and in the open field respectively. The measurements were carried out at around 3 pm every day, repeated 3 times, and continued for 15 days.

[0030] 1.3 Determination of the effect of covering with nano insect-proof net on temperature and humidity A temperature and humidity recorder was used to measure the temperature and humidity in the middle of the nano-silica insect-proof net. One day was selected during the peak flowering and podding period of cowpea to record the changes in temperature and humidity for 24 hours. The temperature and humidity recorder was placed in the middle of the insect-proof net shed and in the open field. The temperature and humidity in the shed and the open field were continuously monitored for 1 day. The temperature and humidity recorder recorded once every 5 minutes, for a total of 12 times. The statistics were set at every 4 hours as a time point, and the temperature and humidity differences between different treatments at each time point were analyzed.

[0031] 1.4 Inductively coupled chromatography (ICC) detection of silicon content in nano-insect repellent nets Nano-silica insect-proof net samples were collected from the field. 0.1 g of the nano-silica insect-proof net sample was digested with concentrated nitric acid and hydrogen peroxide, and the silicon content in the digested sample was detected using an ICP-OES instrument (Agilent 5800).

[0032] Field test results of nano-silica insect-proof net 2.1 Survey results on the occurrence of common giant thrips in the field During the flowering period of cowpea, an investigation was conducted on cowpea flowers in ordinary insect-proof nets and nano-net sheds, and the population of common thrips in the cowpea flowers was counted. The common thrips damage rate in the 80-mesh net shed was 7.76 per flower, and the common thrips damage rate in the 20-mesh nano-net shed was 2.8 per flower.

[0033] 2.2 Determination of the effect of covering with nano-silica insect screen on light intensity and ventilation After covering the semi-enclosed insect-proof net, the light intensity in the center of the shed was similar to that in the open field at each test time point from day 1 to day 15. The open field light intensity was 12,000-729,100 LUX, the light intensity in the 80-mesh insect-proof net was 11,800-72,900 LUX, and the light intensity in the 20-mesh nano-net was 10,500-72,500 LUX. There was no significant difference in wind speed inside the nano insect-proof net shed and in the open air at each test time point from day 1 to day 15. The wind speed inside the 80-mesh insect-proof net was the smallest, with the open air wind speed ranging from 0.2 to 1.6 m / s. The wind speed inside the 20-mesh nano net shed was 0.2 to 1.4 m / s, and the wind speed inside the 80-mesh insect-proof net shed was 0.1 to 1.39 m / s.

[0034] 2.3 Determination of the effect of covering with nano-silica insect-proof net on temperature and humidity After covering with insect-proof nets, the humidity in the net shed and the open field showed significant difference only between 10:00 and 14:00 within one day. The humidity in the open field was 35.5-75.7wt%, the humidity in the 80-mesh insect-proof net shed was 36-79.2wt%, and the humidity in the 20-mesh nano-net shed was 35.8-77.2wt%.

[0035] After covering with the insect-proof net, there was no significant difference in temperature between the shed and the open field at 4h, 8h, 12h, 16h, 20h and 20h. The temperature in the open field was 24.6-32.5℃, the temperature in the shed with 80-mesh insect-proof net was 23.1-32.5℃, and the temperature in the shed with 20-mesh nano-net was 23.5-31.3℃.

[0036] 2.4 Results of inductively coupled chromatography testing of silicon content in nano-insect repellent nets Table 3 Determination of silicon content in nano insect-proof net

[0037] As shown in Table 3, the nano-insect-proof net contains about 27.38 wt% of nano-silicon dioxide.

[0038] 3. Results and Analysis (1) In the field test, the insect repellent effect of the semi-enclosed 20-mesh nano-silica insect-proof net was significantly better than that of the 80-mesh ordinary insect-proof net. In field applications, the nano-silica insect-proof net can effectively reduce the damage caused by bean thrips; (2) The results of the field test showed that there was no significant difference in the light, temperature and wind speed data between the 20-mesh nano-silica insect-proof net in a semi-enclosed environment and the open air environment. The humidity in the 20-mesh nano-silica net shed was also better than that of the 80-mesh ordinary insect-proof net. The 20-mesh nano-silica insect-proof net ensured normal light and ventilation for the crops in the net. (3) About 27.38 wt% of nano-silica content was detected on the nano-silica insect repellent net that had been used in the field for about 2 months; Nano-silica insect-proof net enhances the insect-proof effect while also ensuring normal ventilation conditions within the net.

[0039] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing a nano masterbatch, characterized in that: The following steps are involved: S1, hydrophobic nano-silica produced by the vapor phase method was selected and dried at 80°C for 2 hours in advance, and linear low-density polyethylene was dried at 80°C for 4 hours; S2, adding white oil to the nano-silica and stirring at a stirring speed of 2000-3000 rpm for 30 minutes to form a uniform suspension; S3, mixing and melting the dried linear low-density polyethylene with the suspension at a rotation speed of 200-250 rpm, extruding, cooling and granulating the melt-blended material to obtain a nano masterbatch; The white oil content in the nano masterbatch is 0.5-2wt%, the nano silicon dioxide content is 1-5wt%, and the linear low-density polyethylene content is 93-98.5wt%.

2. A method for preparing a nano insect-proof net, characterized in that: The following steps are involved: The method for preparing a nano masterbatch according to claim 1 is used to obtain a nano masterbatch comprising linear low-density polyethylene, nano-silicon dioxide and white oil; S1, drying high-density polyethylene at 80°C for 4 hours, premixing the nano masterbatch with the weathering masterbatch at a rotation speed of 500-800 rpm for 10-15 minutes; S2, mixing high-density polyethylene, pre-mixed nano masterbatch and weather-resistant masterbatch to obtain a blend, and adding the blend to an extruder to obtain fiber filaments through melting, drawing, stretching and winding; S3, straightening and dividing the fiber filaments into discs, and weaving them into a net through a warp knitting machine and a braiding machine.

3. The method for preparing a nano insect-proof net according to claim 2, characterized in that: The high-density polyethylene content in the blend is 92-96wt%, the nano masterbatch content is 2-5wt%, and the weather-resistant masterbatch content is 2-3wt%.

4. The method for preparing a nano insect-proof net according to claim 2, characterized in that: The high-density polyethylene grade is PE5000S.

5. A nano insect-proof net, prepared by the preparation method of the nano insect-proof net according to any one of claims 2 to 4.

6. The nano insect-proof net according to claim 5, characterized in that: The diameter of the nano insect-proof mesh is 0.16-0.18 mm.

7. The nano insect-proof net according to claim 5, characterized in that: The nano-insect-proof net has a square mesh, and the mesh size is 0.5mm*0.5mm-0.85mm*0.85mm.

8. Use of the nano insect-proof net according to any one of claims 5 to 7 in agricultural pest control.

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