Method for preparing forming granular material for drip irrigation tape based on waste PVC mulching film and application of forming granular material

Abstract

The invention provides a method for preparing a forming granular material for a drip irrigation tape based on a waste PVC mulching film and application of the forming granular material. The method comprises the following steps: sequentially carrying out cleaning, crushing friction and cleaning dehydration on the collected waste PVC mulching film to obtain a regenerated PVC crushed material; the preparation method comprises the following steps: premixing 30-50 wt% of regenerated PVC crushed material and 50-70 wt% of raw PVC powder at 60-80 DEG C to form PVC resin; a mixed material containing 100 parts by mass of the PVC resin, 1-3 parts by mass of a stabilizer and 0.5-0.9 part by mass of a lubricant is sequentially subjected to blending and extrusion granulation, and the formed granular material for the agricultural drip irrigation tape is obtained. According to the method provided by the invention, the problems that the recycling rate of waste PVC is low and the cost of the drip irrigation tape is relatively high can be solved at the same time, and the drip irrigation tape prepared based on the regenerated PVC crushed material has good chemical stability, mechanical strength and long-acting service characteristics.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of agricultural facility materials, and particularly relates to a method for preparing a formed granular material for a drip irrigation belt based on waste PVC mulch film. BACKGROUND

[0002] Drip irrigation technology is an effective water-saving irrigation method in arid and water-deficient areas, and the water utilization rate can reach 95%. Drip irrigation technology mainly drips water drop by drop uniformly and slowly near the roots of crops through pipes, and is widely used in fruit trees, vegetables, economic crops and greenhouse irrigation due to its advantages of saving water resources, preventing soil salinization, maintaining soil water content and fertility, etc. and can also be used for field crop irrigation in arid and water-deficient areas.

[0003] Drip irrigation technology relies on drip irrigation belts to achieve precise water use. On the one hand, the existing technology usually uses virgin polyethylene (PE) or polyvinyl chloride (PVC) resin to prepare agricultural drip irrigation belts, which has the problem of high production cost. On the other hand, PVC mulch film is widely used in farmland in China, but the recycling rate of waste PVC mulch film is low, and a large amount of discarded PVC mulch film cannot be effectively collected and is discarded at random in the field or simple landfill, which not only pollutes the soil and water environment for a long time, but also causes great loss of material resources. Even the part that is recycled is mostly downcycled and reused through simple technology, such as being made into low-end building materials, etc. Such primary applications do not fully utilize the inherent performance value of PVC, and the overall recycling rate is much lower than the potential demand. Therefore, it is of great significance to develop a method for preparing a formed granular material for an agricultural drip irrigation belt based on waste PVC mulch film to solve the problems of high production cost of agricultural drip irrigation belts and low recycling rate of waste PVC mulch film. SUMMARY

[0004] To solve all or part of the above technical problems, the present application provides the following technical solutions:

[0005] The first aspect of the present application provides a method for preparing a formed granular material for a drip irrigation belt based on waste PVC mulch film, comprising:

[0006] The collected waste PVC mulch film is sequentially subjected to cleaning, crushing, friction and cleaning and dewatering treatment steps to obtain regenerated PVC crushed material;

[0007] 30-50 wt% of the regenerated PVC crushed material and 50-70 wt% of virgin PVC powder are pre-mixed at 60-80°C to form a PVC resin;

[0008] The mixture material containing 100 parts by mass of the PVC resin, 1-3 parts by mass of the stabilizer and 0.5-0.9 parts by mass of the lubricant is sequentially blended and extrusion granulated to obtain the molding granules for agricultural drip irrigation tape.

[0009] The pre-mixing is carried out at a temperature of 60-80℃, and the PVC is melted by heat to change from solid to fluid, so as to realize the uniform mixing of the virgin PVC powder and the recycled PVC crushed material. If the virgin PVC powder and the recycled PVC crushed material are not uniformly mixed, the performance of the granules will be poor, which is not conducive to the downstream application.

[0010] In some embodiments, 30-40wt% of the recycled PVC crushed material and 60-70wt% of the virgin PVC powder are pre-mixed at 60-80℃.

[0011] In some embodiments, the particle size of the recycled PVC crushed material is 3-5mm.

[0012] In some embodiments, the average polymerization degree of the virgin PVC powder is 1143-1401, and preferably the average polymerization degree is 1250-1350.

[0013] In some embodiments, the pre-mixing time of the recycled PVC crushed material and the virgin PVC powder is 2-3min.

[0014] In some embodiments, the mixture material further includes 0.05-0.12 parts by mass of a colorant. The colorant is used to adjust the color of the granules to meet different requirements.

[0015] In some embodiments, the stabilizer includes one or a combination of organic tin, calcium-zinc stabilizer, lead salt composite stabilizer, barium-cadmium-zinc stabilizer or calcium stearate.

[0016] In some preferred embodiments, the stabilizer includes calcium stearate and at least one of organic tin, calcium-zinc stabilizer, lead salt composite stabilizer and barium-cadmium-zinc stabilizer.

[0017] In some preferred embodiments, the stabilizer includes organic tin and calcium stearate in a mass ratio of 1:(0.1-0.4); or the stabilizer includes calcium-zinc stabilizer and calcium stearate in a mass ratio of 1:(0.1-0.2); or the stabilizer includes lead salt composite stabilizer and calcium stearate in a mass ratio of 1:(0.5-0.8); or the stabilizer includes barium-cadmium-zinc stabilizer and calcium stearate in a mass ratio of 1:(0.3-0.4). These combinations of stabilizers can effectively prevent the thermal decomposition and light aging of the PVC resin during processing and use.

[0018] In some embodiments, the lubricant comprises a combination of one or more of polyethylene wax, oxidized polyethylene, paraffin wax, calcium stearate, butyl stearate, stearyl alcohol, or epoxy soybean oil.

[0019] In some embodiments, the lubricant comprises polyethylene wax, oxidized polyethylene, and epoxy soybean oil in a mass ratio of 1:(0.1-0.3):(1-3); or the lubricant comprises paraffin wax, calcium stearate, and stearyl alcohol in a mass ratio of 1:(0.08-0.16):(2-2.5); or the lubricant comprises polyethylene wax, butyl stearate, and epoxy soybean oil in a mass ratio of 1:(0.15-0.28):(1.5-2.5). The above three combinations of the lubricant provided by the present application can effectively reduce the processing viscosity of the material, improve the processing fluidity of the PVC resin, and reduce the energy consumption and wear during processing.

[0020] In some embodiments, the cleaning is mechanical cleaning, which comprises cutting and separating the collected waste PVC mulch film, and then dry cleaning the waste PVC mulch film to remove large-particle impurities.

[0021] In some embodiments, the crushing and rubbing comprises crushing the waste PVC mulch film after the mechanical cleaning, and then performing high-speed rubbing treatment on the crushed waste PVC mulch film to remove small-particle impurities.

[0022] In some embodiments, the cleaning and dewatering comprises rinsing the waste PVC mulch film after the crushing and rubbing, and then dewatering, wherein the dewatering rate is greater than 98% before the preparation of the mixture.

[0023] In some embodiments, the blending comprises hot mixing at a temperature of 140-160°C, and then cold mixing at a temperature of 40-50°C. The purpose of the hot mixing is to make the PVC and other additives into a fluid, and to realize the uniform distribution of the additives in the PVC in a flowing state. At a temperature of 140-160°C, part of the additives can be coupled with the polyvinyl chloride molecular chain, thereby improving the structure and performance of the granules. After the additives enter the PVC fluid in the hot mixing, the additives and the PVC form a whole and firm structure through the cooling (cold mixing).

[0024] Exemplarily, the mixture is placed in a feeding station, pre-mixed and buffered in a pre-mixing bin, blown by air to a metering tank for metering, and the metered material is fed into a hot mixing unit under the action of gravity for hot mixing, the rotation speed of the main shaft in the hot mixing unit is controlled to be 500-600 rpm, and the temperature is controlled to be 140-160 DEG C; the hot-mixed material is self-flowed to a cold mixing unit, the rotation speed of the main shaft in the cold mixing unit is 65 rpm, and the temperature is 40-50 DEG C. The stirring time under the hot mixing condition can be 15-20 min, and the stirring time under the cold mixing condition can be 5-10 min.

[0025] In some embodiments, the temperature of the extrusion granulation is 150-170 DEG C. Exemplarily, the process conditions of the extrusion granulation include: after the blended PVC fluid is sent to a PVC mixing buffer bin, heating is performed on the granulation main machine, the temperature of the granulation main machine is controlled to be 150-170 DEG C, the extrusion output is controlled to be 400-500 kg / h, and the granulation is performed on the granulation main machine, and the diameter of the cut granulation is controlled to be 3.5 mm. After the cut granulation is removed by a cyclone separator and a vibrating screen, the qualified products are sent to a PVC mixing material finished product bin.

[0026] The second aspect of the present application provides a shaped granular material for drip irrigation tape, which is prepared by the preparation method described in any one of the technical solutions.

[0027] The third aspect of the present application provides a preparation method of agricultural drip irrigation tape, which comprises

[0028] The shaped granular material for drip irrigation tape is prepared by the preparation method described in any one of the technical solutions;

[0029] The shaped granular material for drip irrigation tape is subjected to melting, injection molding and shaping treatment to obtain the agricultural drip irrigation tape.

[0030] The fourth aspect of the present application provides an agricultural drip irrigation tape, which is prepared by the preparation method described in any one of the technical solutions.

[0031] Compared with the prior art, the present application has at least the following beneficial effects:

[0032] (1) The present application utilizes the characteristics of strong mechanical properties of waste PVC mulch and easy recycling, processes the recycled waste PVC mulch through mechanical cleaning, crushing and rubbing, cleaning and dewatering, and obtains regenerated PVC crushed material with high purity; on this basis, the regenerated PVC crushed material is compounded with virgin PVC powder, and stabilizers, lubricants and other additives are added to prepare a shaped granular material for agricultural drip irrigation tape; while meeting the use standards of agricultural drip irrigation tape, the drip irrigation tape can be recycled, the production cost of the drip irrigation tape is reduced, the recycling rate of waste PVC is improved, and the energy saving, carbon reduction and environmental protection benefits are improved.

[0033] (2) The drip irrigation belt prepared by the method has good chemical stability, excellent acid and alkali resistance and corrosion resistance, can resist the erosion of various chemicals, has good mechanical strength, excellent pressure resistance, is not easy to deform and crack, has excellent long-term service characteristics, good aging resistance, is not easy to deteriorate and age, has a long service life, and is made of materials meeting the drip irrigation belt hygiene standards and will not cause secondary pollution. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present application. The specific functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and for teaching those skilled in the art to employ the representative basis of the present application in different ways in any appropriate detailed embodiment.

[0035] In addition, unless otherwise specified, the various raw materials used in the following examples can be obtained from the market or the like, and the various production and testing equipment used is known in the art, and the testing methods used are also known in the art.

[0036] Example 1

[0037] The present embodiment provides a method for preparing a molded granular material for drip irrigation belts based on waste PVC mulch film, which specifically comprises the following steps:

[0038] 1. Collecting waste PVC mulch film and sequentially performing mechanical cleaning, crushing and rubbing, and cleaning and dewatering treatment:

[0039] (1) Mechanical cleaning: pour the mechanically recycled waste PVC mulch film containing impurities into the feed bin, and send it to the cutting machine through the screw feeder for segmentation. The segmented PVC mulch film is then conveyed to the film dry cleaning machine through the belt conveyor. The waste PVC mulch film is separated from large particle impurities such as branches and soil in the film dry cleaning machine, and the mechanically cleaned PVC mulch film is continuously conveyed to the outside of the equipment through the parallel impurity conveyor in the film dry cleaning machine.

[0040] (2) Crushing and rubbing: the mechanically cleaned PVC mulch film conveyed by the parallel impurity conveyor is sent to the crusher through the belt conveyor for crushing, and regenerated PVC crushed material with a particle size in the range of 3-5 mm is obtained. The regenerated PVC crushed material is sent to the high-speed rubbing machine by the screw feeder. Under the action of the blades, the process of manual rubbing is simulated, and the preliminary separation of the PVC mulch film from small particles of soil is realized.

[0041] (3) washing and dewatering: the regenerated PVC broken material after rubbing by the high-speed rubbing machine is directly put into the rinsing pool, soaked in the rinsing pool, and brushed to the screw feeder under the driving of the rolling brush, and the washed regenerated PVC broken material is sent to the dewatering machine for dewatering by the screw feeder, and the dewatered regenerated PVC broken material is sent to the cyclone bin by the cyclone separator.

[0042] 2, the mixture is prepared by using the regenerated PVC broken material obtained above, and the composition of the mixture in the embodiment is as follows in mass fraction:

[0043] PVC resin: 100 parts by mass; the preparation method of the PVC resin is to mix 40 wt% of the regenerated PVC broken material and 60 wt% of the virgin PVC powder, and pre-mix at 80°C for 3 min, wherein the average polymerization degree of the virgin PVC powder is 1286;

[0044] stabilizer: 2.2 parts by mass, the composition is: calcium-zinc stabilizer (purchased from Jiangsu Beden New Material Technology Co., Ltd., product brand K-128) and calcium stearate in a mass ratio of 1:0.1;

[0045] lubricant: 0.8 parts by mass, the composition is: polyethylene wax, oxidized polyethylene and epoxy soybean oil in a mass ratio of 1:0.3:1;

[0046] black colorant: 0.01 parts by mass.

[0047] 3, the above raw materials are added to the mixing unit through the feeding station, mixed uniformly in the mixing unit to ensure that each component is fully dispersed to obtain the mixture; the above mixture is sent to the feeding bin of the high-speed blender through the screw feeder, the main shaft speed of the hot mixing unit is controlled at 600 rpm, the temperature is 150°C, and the stirring time is 20 min; the mixture after hot mixing is self-flowed to the cold mixing unit, the main shaft speed of the cold mixing unit is controlled at 65 rpm, the temperature is 50°C, and the stirring time is 10 min.

[0048] 4, the mixture treated in step 3 is placed in a twin-screw extruder for extrusion and granulation, the temperature is 160°C, and the formed granular material for agricultural drip irrigation belt is prepared.

[0049] Example 2

[0050] Example 2 is basically the same as Example 1, the only difference is that the composition of the mixture in Example 2 is as follows:

[0051] PVC resin: 100 parts by mass, the composition and preparation method are the same as those in Example 1;

[0052] stabilizer: 1.2 parts by mass, the composition is thiol organotin and calcium stearate in a mass ratio of 1:0.2;

[0053] Lubricant: 0.6 parts by mass, composed of polyethylene wax, oxidized polyethylene and epoxy soybean oil at a mass ratio of 1:0.25:1.2.

[0054] The rest is the same as example 1, and will not be repeated here.

[0055] Example 3

[0056] Example 3 is different from example 1 only in that the mixture in example 3 contains 33wt% of recycled PVC broken material and 67wt% of virgin PVC powder in 100 parts by mass of PVC resin.

[0057] The rest is the same as example 1, and will not be repeated here.

[0058] Example 4

[0059] Example 4 is different from example 1 only in that the composition of the mixture in example 4 is:

[0060] PVC resin: 100 parts by mass, containing 33wt% of recycled PVC broken material and 67wt% of virgin PVC powder;

[0061] Stabilizer: 1.2 parts by mass, composed of thiol organotin and calcium stearate at a mass ratio of 1:0.2;

[0062] Lubricant: 0.6 parts by mass, composed of polyethylene wax, oxidized polyethylene and epoxy soybean oil at a mass ratio of 1:0.25:1.2.

[0063] The rest is the same as example 1, and will not be repeated here.

[0064] Example 5

[0065] 1. The waste PVC mulch recycling process in example 5 is the same as example 1;

[0066] 2. The recycled PVC broken material obtained above is used to prepare the mixture, and the composition of the mixture in this example is:

[0067] PVC resin: 100 parts by mass; the preparation method of PVC resin is to mix 30wt% of recycled PVC broken material and 70wt% of virgin PVC powder, and pre-mix at 60℃ for 2min;

[0068] Stabilizer: 2.2 parts by mass, composed of calcium-zinc stabilizer (purchased from Jiangsu Beden New Material Technology Co., Ltd., product brand K-128) and calcium stearate at a mass ratio of 1:0.1;

[0069] Lubricant: 0.8 parts by mass, composition: polyethylene wax, oxidized polyethylene and epoxy soybean oil in a mass ratio of 1:0.3:1.

[0070] 3、The above-mentioned raw materials were added to the mixing unit through the feeding station, and were uniformly mixed in the mixing unit to ensure that the components were fully dispersed to obtain the mixed material; the above-mentioned mixed material was sent to the feeding bin of the high-speed blender through the screw feeder, the main shaft speed of the hot mixing unit was controlled to be 500 rpm, the temperature was 140℃, and stirring was performed for 15 min; the hot-mixed mixed material was self-flowed to the cold mixing unit, the main shaft speed of the cold mixing unit was controlled to be 65 rpm, the temperature was 40℃, and stirring was performed for 5 min.

[0071] 4、The mixed material treated in step 3 was placed in a twin-screw extruder for extrusion and granulation, and the temperature was 150℃, to obtain the formed granular material for agricultural drip irrigation tape.

[0072] Example 6

[0073] 1、The recycling process of the waste PVC mulch film in Example 6 is the same as that in Example 1;

[0074] 2、The above-mentioned regenerated PVC crushed material was used to prepare the mixed material, and the composition of the mixed material in this embodiment was as follows in parts by mass:

[0075] PVC resin: 100 parts by mass; the preparation method of the PVC resin was to mix 50wt% of the regenerated PVC crushed material and 50wt% of the virgin PVC powder, and to pre-mix at 70℃ for 3 min;

[0076] Stabilizer: 2.2 parts by mass, composition: calcium-zinc stabilizer (purchased from Jiangsu Beden New Material Technology Co., Ltd., trade name: K-128) and calcium stearate in a mass ratio of 1:0.1;

[0077] Lubricant: 0.8 parts by mass, composition: polyethylene wax, oxidized polyethylene and epoxy soybean oil in a mass ratio of 1:0.3:1.

[0078] 3、The above-mentioned raw materials were added to the mixing unit through the feeding station, and were uniformly mixed in the mixing unit to ensure that the components were fully dispersed to obtain the mixed material; the above-mentioned mixed material was sent to the feeding bin of the high-speed blender through the screw feeder, the main shaft speed of the hot mixing unit was controlled to be 500 rpm, the temperature was 140℃, and stirring was performed for 15 min; the hot-mixed mixed material was self-flowed to the cold mixing unit, the main shaft speed of the cold mixing unit was controlled to be 65 rpm, the temperature was 40℃, and stirring was performed for 5 min.

[0079] 4、The mixed material treated in step 3 was placed in a twin-screw extruder for extrusion and granulation, and the temperature was 150℃, to obtain the formed granular material for agricultural drip irrigation tape.

[0080] Example 7

[0081] The difference between Example 7 and Example 1 is only that the average polymerization degree of the virgin PVC powder in the PVC resin of Example 7 is 1143.

[0082] Example 8

[0083] The difference between Example 8 and Example 1 is only that the average polymerization degree of the virgin PVC powder in the PVC resin of Example 8 is 1401.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is only that the PVC resin of Comparative Example 1 uses 100% virgin PVC powder. The rest is the same as Example 1, which is not repeated here.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 1 is only that:

[0088] (1) The PVC resin of Comparative Example 2 uses 100% virgin PVC powder;

[0089] (2) The lubricant in the mixture of Comparative Example 2 is 2.3 parts by mass, and the composition of the lubricant is 1:0.3:1 by mass ratio polyethylene wax, oxidized polyethylene and epoxy soybean oil.

[0090] The rest is the same as Example 1, which is not repeated here.

[0091] Comparative Example 3

[0092] The difference between Comparative Example 3 and Example 1 is only that the PVC resin of Comparative Example 3 uses 100% recycled PVC broken material. The rest is the same as Example 1, which is not repeated here.

[0093] The present application also uses the above-mentioned agricultural drip irrigation belt forming granular material prepared by the examples and comparative examples to prepare a drip irrigation belt, which specifically includes:

[0094] The above-mentioned forming granular material in the examples and comparative examples is respectively melted and injection molded to form a drip irrigation belt.

[0095] The tensile strength and elongation at break of the prepared drip irrigation belt are tested, and the test method is according to GB / T19812.3-2017, and the test results are shown in Table 1:

[0096] Table 1. Performance comparison table of drip irrigation belt

[0097]

[0098]

[0099] Comparing Table 1, it is found that the elongation at break of the drip irrigation belts prepared by compounding the recycled PVC broken material and the virgin PVC powder material in a certain proportion in Examples 1-4 is better, and the tensile strength is slightly lower than that of Comparative Examples 1 and 2, but reaches the use standard of agricultural drip irrigation belts. The recycled PVC broken material is subjected to long-term light and exposure, resulting in decomposition of part of the PVC in the recycled PVC broken material. The decomposition of the internal structure causes the tensile strength of the agricultural drip irrigation belts prepared by compounding the recycled PVC broken material and the virgin PVC powder material to be slightly reduced. However, since the recycled PVC broken material still contains a small amount of stabilizers and lubricants, the use amount of the PVC modifiers in the original formula is increased, that is, the method provided by the application can prepare agricultural drip irrigation belts with excellent elongation at break and good tensile strength under the premise of less use of additives and lower cost.

[0100] It should be further pointed out that, since the internal structure of the recycled PVC broken material is decomposed, if the amount of the recycled PVC broken material is too high, the tensile strength of the drip irrigation belts will be reduced. It is found through systematic research that, when the amount of the recycled PVC broken material is in the range of 30-40 wt%, the quality of the drip irrigation belts prepared is basically equivalent to that of the drip irrigation belts prepared from 100% virgin PVC powder material, and the production cost of the drip irrigation belts can be reduced by about 20%-25%, while solving the problem of low recycling rate of waste PVC.

[0101] In summary, the application provides a molding granular material for agricultural drip irrigation belts prepared from waste PVC mulch as a core raw material. The PVC is regenerated with high purity (the impurity separation efficiency is more than 90%) through multi-stage pretreatment processes such as mechanical cleaning, crushing and rubbing, rinsing and dewatering. This process converts waste PVC mulch into recyclable PVC particles, reduces white pollution, and meets the needs of circular economy. Based on the method provided by the application, 0.35-0.45 tons of clean waste PVC mulch can be treated per ton of granular material, carbon emissions generated by landfill or incineration are reduced, the utilization rate of waste PVC mulch is improved, and the production cost of drip irrigation belts is significantly reduced.

[0102] In addition, the present inventors have also carried out tests with other raw materials, process operations and process conditions described in the specification with reference to the foregoing examples, and all have obtained relatively ideal results.

[0103] The aspects, embodiments, features and examples of the present application should be considered illustrative, for the purpose of explanation, illustration and description, but not for the purpose of limiting the present application, the scope of which is defined only by the claims.

[0104] While the application has been described with reference to the illustrative embodiments, those skilled in the art will appreciate that various modifications, omissions, and / or additions can be made without departing from the spirit or scope of the application. Additionally, many modifications can be made to adapt a particular situation or material to the teachings of the application without departing from its scope. Therefore, the application is not intended to be limited to the particular embodiments disclosed, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Further, to the extent that the terms first, second, etc. are used herein to describe various elements, these are generally used only as labels, and are not intended to impose numerical requirements on their objects.

Claims

1. A method for preparing shaped granules for drip irrigation tapes based on waste PVC mulch film, characterized by, The application relates to a preparation method of a PVC resin for agricultural drip irrigation belts. The collected waste PVC mulch is sequentially subjected to cleaning, crushing and rubbing, and cleaning and dewatering treatment steps to obtain regenerated PVC crushed material; 30-50wt% of the regenerated PVC crushed material and 50-70wt% of virgin PVC powder are premixed at 60-80 DEG C to form the PVC resin; A mixture containing 100 parts of the PVC resin, 1-3 parts of a stabilizer and 0.5-0.9 parts of a lubricant is sequentially subjected to blending and extrusion granulation to obtain a shaped granular material for agricultural drip irrigation belts.

2. The method of claim 1, wherein: 30-40wt% of the regenerated PVC crushed material and 60-70wt% of virgin PVC powder are premixed at 60-80 DEG C; And / or, the particle size of the regenerated PVC crushed material is 3-5mm; And / or, the average polymerization degree of the virgin PVC powder is 1143-1401, preferably 1250-1350; And / or, the mixture further contains 0.05-0.12 parts of a colorant.

3. The method of claim 1, wherein: The stabilizer comprises one or a combination of organic tin, calcium-zinc stabilizer, lead salt composite stabilizer, barium-cadmium-zinc stabilizer or calcium stearate; Preferably, the stabilizer comprises calcium stearate and at least one of organic tin, calcium-zinc stabilizer, lead salt composite stabilizer and barium-cadmium-zinc stabilizer.

4. The method of claim 3, wherein: The stabilizer comprises organic tin and calcium stearate at a mass ratio of 1:0.1-0.4; or the stabilizer comprises calcium-zinc stabilizer and calcium stearate at a mass ratio of 1:0.1-0.2; or the stabilizer comprises lead salt composite stabilizer and calcium stearate at a mass ratio of 1:0.5-0.8; or the stabilizer comprises barium-cadmium-zinc stabilizer and calcium stearate at a mass ratio of 1:0.3-0.

4.

5. The method of claim 1, wherein: The lubricant comprises one or a combination of polyethylene wax, oxidized polyethylene, paraffin wax, calcium stearate, butyl stearate, stearyl alcohol or epoxy soybean oil.

6. The method of claim 5, wherein: The lubricant comprises polyethylene wax, oxidized polyethylene and epoxy soybean oil at a mass ratio of 1:(0.1-0.3):(1-3); or the lubricant comprises paraffin wax, calcium stearate and stearyl alcohol at a mass ratio of 1:(0.08-0.16):(2-2.5); or the lubricant comprises polyethylene wax, butyl stearate and epoxy soybean oil at a mass ratio of 1:(0.15-0.28):(1.5-2.5).

7. The method of claim 1, wherein, The cleaning is mechanical cleaning, which comprises cutting and separating the collected waste PVC mulch and then dry cleaning the waste PVC mulch; And / or, the crushing and rubbing comprises crushing the waste PVC mulch subjected to the mechanical cleaning and then rubbing the crushed waste PVC mulch; And / or, the cleaning and dewatering comprises rinsing the waste PVC mulch subjected to the crushing and rubbing and then dewatering, and the mixture is prepared after the dewatering rate reaches 98% or above; And / or, the blending comprises first heat mixing at 140-160 DEG C for 15-20min and then cold mixing at 40-50 DEG C for 5-10min. And / or, the temperature of the extrusion granulation is 150-170℃.

8. A shaped granule for use in drip irrigation tape, characterized in that, It is prepared by the preparation method of any one of claims 1-7.

9. A method of making an agricultural drip irrigation tape, characterized by, Comprising The shaped granules for drip irrigation tape are prepared by the preparation method of any one of claims 1-7. The shaped granules for drip irrigation tape are subjected to melting, injection molding and shaping treatment to obtain agricultural drip irrigation tape.

10. An agricultural drip irrigation tape characterized in that, It is prepared by the preparation method of claim 9.

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