Low-water-permeability full-biodegradable mulching film and preparation method thereof

Abstract

The invention relates to a low-permeability full-biodegradable mulching film and a preparation method thereof. The invention relates to a low-water-permeability full-biodegradable mulching film, which is prepared from the following raw materials: PBAT, PLA, PCU, barium sulfate, an epoxy chain extender 4468, an antioxidant 168, an antioxidant 1010, an anti-hydrolysis agent 1010, a hindered amine light stabilizer HS-326, an ultraviolet light absorber UV-360, oxidized polyethlene wax and zinc stearate. According to the low-water-permeability full-biodegradable mulching film and the preparation method thereof, the full-biodegradable mulching film which is low in cost, high in aging resistance and high in water retention is obtained by optimizing the raw materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high polymer materials, and particularly relates to a low-water-permeable full-biodegradable mulching film and a preparation method thereof. BACKGROUND

[0002] China has more than 200 million mu of annual mulching, and the recovery rate of traditional PE and PVC mulching films is less than 10%. The residual film is difficult to degrade in a hundred years, leading to serious "white pollution". Therefore, the improvement of traditional mulching films is imminent.

[0003] PBAT, as a copolyester, has flexibility, suitable processability and complete biodegradability, but the pure material needs to be modified to improve the melt strength, cost and key barrier property (water retention core). PBAT technology has undergone three generations of iteration: the first generation of pure PBAT film has poor aging resistance (insufficient weather resistance), high cost, and weak water retention barrier property; the second generation of blended film reduces the cost by 30-40%, but the high starch content is easy to be brittle, and the aging resistance and water retention performance are not significantly improved; the third generation of composite film greatly enhances the anti-aging ability by introducing light stabilizers and antioxidants, and realizes ultra-thin and water vapor barrier rate improvement (water retention performance optimization), with a degradation rate of more than 90% within 180 days, and high-efficiency degrading bacteria are screened to support "bacteria-film synergy".

[0004] However, there are still core bottlenecks at present, for example: in high ultraviolet regions such as Xinjiang, the contradiction between weather resistance (aging resistance) and soil conservation (water retention) is prominent, and the pure PBAT film is easy to be brittle and lose water retention ability in advance; the latest PBAT / PPC-P composite film reduces the water vapor transmission rate by 61.9% (upgrades water retention), but the cost increases by 15-20%; and the cost of PBAT is 2.5 times that of PE, and the promotion relies on subsidies. Therefore, PBAT mulching film is being improved around the demand for "strong anti-aging, high water retention, controllable degradation and low cost".

[0005] Therefore, the application provides a new low-water-permeable full-biodegradable mulching film and a preparation method thereof, which improves the anti-aging performance and water retention performance by optimizing the raw material composition. SUMMARY

[0006] The application aims to provide a low-water-permeable full-biodegradable mulching film, which improves the anti-aging performance and water retention performance by optimizing the raw material composition.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted is as follows:

[0008] A low-water-permeable full-biodegradable mulching film is prepared from the following raw materials:

[0009] PBAT, PLA, PCU, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, zinc stearate.

[0010] Further, the use amount of the PBAT is 57.5-82.5 parts by weight, the use amount of the PLA is 4-6 parts by weight, the use amount of the PCU is 5-30 parts by weight, the use amount of the barium sulfate is 3-5 parts by weight, the use amount of the epoxy chain extender 4468 is 0.4-0.6 parts by weight, the use amount of the antioxidant 168 is 0.2-0.3 parts by weight, the use amount of the antioxidant 1010 is 0.3-0.5 parts by weight, the use amount of the anti-hydrolysis agent 1010 is 0.4-0.6 parts by weight, the use amount of the hindered amine light stabilizer HS-326 is 0.4-0.6 parts by weight, the use amount of the ultraviolet absorber UV-360 is 0.4-0.6 parts by weight, the use amount of the oxidized polyethylene wax is 0.2-0.3 parts by weight, and the use amount of the zinc stearate is 0.4-0.6 parts by weight.

[0011] Further, the use amount of the PBAT is 57.5-82.5 parts by weight, the use amount of the PLA is 4-6 parts by weight, the use amount of the PCU is 5-30 parts by weight, the use amount of the barium sulfate is 3-5 parts by weight, the use amount of the epoxy chain extender 4468 is 0.4-0.6 parts by weight, the use amount of the antioxidant 168 is 0.2-0.3 parts by weight, the use amount of the antioxidant 1010 is 0.3-0.5 parts by weight, the use amount of the anti-hydrolysis agent 1010 is 0.4-0.6 parts by weight, the use amount of the hindered amine light stabilizer HS-326 is 0.4-0.6 parts by weight, the use amount of the ultraviolet absorber UV-360 is 0.4-0.6 parts by weight, the use amount of the oxidized polyethylene wax is 0.2-0.3 parts by weight, and the use amount of the zinc stearate is 0.4-0.6 parts by weight.

[0012] Further, the use amount of the PCU is 20 parts by weight, and the use amount of the barium sulfate is 4 parts by weight.

[0013] Another object of the present application is to provide a preparation method of the low-water-permeable full-biodegradable mulch film, which is simple and easy to implement industrially.

[0014] In order to achieve the above object, the technical scheme adopted is:

[0015] The preparation method of the low-water-permeable full-biodegradable mulch film comprises the following steps:

[0016] (1)PBAT, PLA5, PCU5-30, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, zinc stearate are stirred at 70-80℃, and after being uniformly mixed, the material 1 is obtained;

[0017] (2) The material 1 is melt-extruded through a high-torque double-screw extruder, and then cooled to obtain the material 2;

[0018] (3) The material 2 is blown into a film to obtain the low-water-permeable fully biodegradable mulch film.

[0019] Further, in step (1), the stirring temperature is 75℃, and the time is 10-20min

[0020] Further, in step (2), the melt-extrusion temperature is 155℃, 160℃, 165℃, 170℃, 175℃, 175℃, 175℃, 170℃, 165℃, 165℃ from the first section to the tenth section, the extruder feeding current is 5Hz, and the rotation speed is 160rpm.

[0021] Further, in step (3), the film blowing is carried out through a film blowing machine, and the temperature of the first zone to the fifth zone is 145℃, 150℃, 155℃, 160℃, 160℃.

[0022] Further, in step (3), the blow ratio during the film blowing process is 3.2:1.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] 1、The technical scheme of the present application improves the anti-aging and water retention properties of the product by using functional additives such as epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, and ultraviolet absorber UV-360, thereby improving the anti-aging and water retention properties.

[0025] 2、In the technical scheme of the present application, the price of PCU is close to that of PBAT, and its introduction does not significantly increase the cost. At the same time, the introduction of PCU can improve the anti-aging and water retention properties of the fully biodegradable mulch film.

[0026] 3、In the technical scheme of the present application, the introduction of barium sulfate can improve the anti-aging and water retention properties of the fully biodegradable mulch film.

[0027] 4、In the technical scheme of the present application, the synergistic effect of barium sulfate and PCU significantly improves the water retention and anti-aging properties of the fully biodegradable mulch film. DETAILED DESCRIPTION

[0028] In order to further illustrate the low water permeable full biodegradable mulching film and the preparation method thereof of the present application, and achieve the intended purpose of the present application, the low water permeable full biodegradable mulching film and the preparation method thereof according to the present application, the specific embodiments, structures, features and effects thereof are described in detail as follows. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0029] The low water permeable full biodegradable mulching film and the preparation method thereof of the present application will be further described in detail as follows by combining specific embodiments:

[0030] The technical scheme of the present application is as follows:

[0031] The low water permeable full biodegradable mulching film is prepared from the following raw materials:

[0032] PBAT, PLA, PCU, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, and zinc stearate.

[0033] Preferably, the amount of PBAT is 57.5-82.5 parts by weight, the amount of PLA is 4-6 parts by weight, the amount of PCU is 5-30 parts by weight, the amount of barium sulfate is 3-5 parts by weight, the amount of epoxy chain extender 4468 is 0.4-0.6 parts by weight, the amount of antioxidant 168 is 0.2-0.3 parts by weight, the amount of antioxidant 1010 is 0.3-0.5 parts by weight, the amount of anti-hydrolysis agent 1010 is 0.4-0.6 parts by weight, the amount of hindered amine light stabilizer HS-326 is 0.4-0.6 parts by weight, the amount of ultraviolet absorber UV-360 is 0.4-0.6 parts by weight, the amount of oxidized polyethylene wax is 0.2-0.3 parts by weight, and the amount of zinc stearate is 0.4-0.6 parts by weight.

[0034] Further preferably, the amount of PBAT is 57.5-82.5 parts by weight, the amount of PLA is 5 parts by weight, the amount of PCU is 5-30 parts by weight, the amount of barium sulfate is 4 parts by weight, the amount of epoxy chain extender 4468 is 0.5 parts by weight, the amount of antioxidant 168 is 0.3 parts by weight, the amount of antioxidant 1010 is 0.4 parts by weight, the amount of anti-hydrolysis agent 1010 is 0.5 parts by weight, the amount of hindered amine light stabilizer HS-326 is 0.5 parts by weight, the amount of ultraviolet absorber UV-360 is 0.5 parts by weight, the amount of oxidized polyethylene wax is 0.3 parts by weight, and the amount of zinc stearate is 0.5 parts by weight.

[0035] Further preferably, the amount of PCU is 20 parts by weight, and the amount of barium sulfate is 4 parts by weight.

[0036] The preparation method of the above-mentioned low-water-permeable full-biodegradable mulch film comprises the following steps:

[0037] (1) PBAT, PLA5, PCU5-30, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, and zinc stearate are stirred at 70-80°C, and then uniformly mixed to obtain material 1;

[0038] (2) The material 1 is melt-extruded through a high-torque double-screw extruder, and then cooled to obtain material 2;

[0039] (3) The material 2 is blown into a film to obtain the low-water-permeable full-biodegradable mulch film.

[0040] Further, in step (1), the stirring temperature is 75°C, and the time is 10-20 min

[0041] Further, in step (2), the melt-extrusion temperature is 155°C, 160°C, 165°C, 170°C, 175°C, 175°C, 175°C, 170°C, 165°C, and 165°C from the first section to the tenth section, respectively, the extruder feeding current is 5 Hz, and the rotation speed is 160 rpm.

[0042] Preferably, in step (3), the film blowing is performed through a film blowing machine, and the temperature of the first zone to the fifth zone is 145°C, 150°C, 155°C, 160°C, and 160°C, respectively.

[0043] Preferably, in step (3), the blow-up ratio during the film blowing process is 3.2:1.

[0044] The raw materials used in the examples are all conventional raw materials in the art, which can be obtained commercially or by other conventional means in the art. The barium sulfate used in the examples is nano barium sulfate whisker.

[0045] Example 1.

[0046] The raw materials (total mass 15 kg) include: PBAT 57.5 parts by weight, PLA 4 parts by weight, PCU 30 parts by weight, barium sulfate 3 parts by weight, epoxy chain extender 4468 0.4 parts by weight, antioxidant 168 0.2 parts by weight, antioxidant 1010 0.3 parts by weight, anti-hydrolysis agent 1010 0.4 parts by weight, hindered amine light stabilizer HS-326 0.4 parts by weight, ultraviolet absorber UV-360 0.4 parts by weight, oxidized polyethylene wax 0.2 parts by weight, zinc stearate 0.4 parts by weight.

[0047] The specific operation steps are as follows:

[0048] (1) Material and additive blending

[0049] The raw materials were mixed at 350 rpm for 15 minutes in a high-mixing pot at 70°C to ensure uniform mixing of the raw materials and additives, obtaining material 1.

[0050] (2) Melt extrusion using a high-torque twin-screw extruder

[0051] The blended material 1 was added to a high-torque twin-screw extruder for melt extrusion. The extrusion temperature of the first to tenth sections was 155°C, 160°C, 165°C, 170°C, 175°C, 175°C, 175°C, 170°C, 165°C, and 165°C, respectively. The extruder feeding current was 5 Hz, and the rotation speed was 160 rpm. The extruded melt was cooled using an air-cooled conveyor belt, obtaining the modified mulch material, i.e., material 2.

[0052] (3) Melt blowing using a mulch film blowing machine

[0053] The material 2 was added to a mulch film blowing machine for film blowing. The blowing temperature of the first to fifth zones was 145°C, 150°C, 155°C, 160°C, and 160°C, respectively. The die temperature was 160°C, the film stretching rate was 53 Hz, the blow ratio was 3.2:1, and the film thickness was 10 um, obtaining the low-water-permeable fully biodegradable mulch film.

[0054] Example 2.

[0055] The raw materials (total mass of 15 kg) include: 82.5 parts by weight of PBAT, 6 parts by weight of PLA, 5 parts by weight of PCU, 5 parts by weight of barium sulfate, 0.6 parts by weight of epoxy chain extender 4468, 0.3 parts by weight of antioxidant 168, 0.5 parts by weight of antioxidant 1010, 0.6 parts by weight of hydrolysis-resistant agent 1010, 0.6 parts by weight of hindered amine light stabilizer HS-326, 0.6 parts by weight of ultraviolet absorber UV-360, 0.3 parts by weight of oxidized polyethylene wax, and 0.6 parts by weight of zinc stearate.

[0056] The specific operation steps are as follows:

[0057] (1) Material and additive blending

[0058] The raw materials were mixed at 80°C in a high-speed mixer for 15 minutes at 350 rpm to ensure uniform mixing of the raw materials and additives, and material 1 was obtained.

[0059] (2) Melt extrusion using a high-torque double-screw extruder

[0060] The blended material 1 was added to a high-torque double-screw extruder for melt extrusion. The extrusion temperatures of the first to tenth sections were 155°C, 160°C, 165°C, 170°C, 175°C, 175°C, 175°C, 170°C, 165°C, and 165°C, respectively. The extruder feeding current was 5 Hz, and the rotation speed was 160 rpm. The melt extrusion was cooled using an air-cooled conveyor belt, and the modified mulch material, i.e., material 2, was obtained.

[0061] (3) Melt blown film using a mulch film blowing machine

[0062] The material 2 was added to a mulch film blowing machine for film blowing. The blowing temperatures of the first to fifth zones were 145°C, 150°C, 155°C, 160°C, and 160°C, respectively. The die temperature was 160°C. The film stretching rate was 53 Hz. The blow ratio was 3.2:1. The film thickness was 10 um. The low-water-permeable fully biodegradable mulch film was obtained.

[0063] Example 3.

[0064] The specific operation steps are as follows:

[0065] (1) Material and additive blending

[0066] The 15 kg of raw materials were mixed at 75°C in a high-speed mixer for 15 minutes at 350 rpm to ensure uniform mixing of the raw materials and additives, and material 1 was obtained.

[0067] The mass percentages of each material and additive in the raw materials are shown in Table 1 (including Table 1-1 and Table 1-2).

[0068] Table 1-1

[0069] No. PBAT PLA PCU Barium sulfate Calcium carbonate Talc Epoxy chain extender 4468 1 91.5 5 0 0 0 0 0.5 2 87.5 5 0 4 0 0 0.5 3 82.5 5 5 4 0 0 0.5 4 77.5 5 10 4 0 0 0.5 5 72.5 5 15 4 0 0 0.5 6 67.5 5 20 4 0 0 0.5 7 67.5 5 20 0 4 0 0.5 8 67.5 5 20 0 0 4 0.5 9 62.5 5 25 4 0 0 0.5 10 57.5 5 30 4 0 0 0.5

[0070] Table 1-2

[0071]

[0072]

[0073] (2) Melting extrusion using a high-torque double-screw extruder

[0074] The blended material 1 was added to a high-torque double-screw extruder for melting extrusion. The extrusion temperatures of the first to tenth sections were 155°C, 160°C, 165°C, 170°C, 175°C, 175°C, 175°C, 170°C, 165°C, and 165°C, respectively, the extruder feeding current was 5 Hz, and the rotation speed was 160 rpm. The extruded melt was cooled using an air-cooled conveyor belt, and the modified mulch modified material, i.e., material 2, was obtained.

[0075] (3) Melting blown film using a mulch blown film machine

[0076] The material 2 was added to a mulch blown film machine for blown film, and the blown film temperatures of the first to fifth sections were 145°C, 150°C, 155°C, 160°C, and 160°C, respectively, the die temperature was 160°C, the film stretching rate was 53 Hz, the blow-up ratio was 3.2:1, and the film thickness was 10 um, and the low-water-permeable fully biodegradable mulch was obtained.

[0077] (4) Performance test and evaluation of the mulch

[0078] The blown film was tested for transverse and longitudinal mechanical properties, thermodynamic properties, optical properties, water retention properties, and field aging properties. The mechanical properties were tested according to the GB / T1040.3 detection standard specified in GB / T35795-2017, the thermodynamic properties were tested according to the GB / T19466.3 detection standard specified in GB / T

[0079] 32366-2025, the optical properties were tested according to the detection means specified in GB / T2410-2008, the water retention properties were tested according to GB / T 1037, and the field aging properties were tested according to the Biodegradable Mulch Evaluation Technical Specification. The specific test performance is shown in Table 2 (including Table 2-1 and Table 2-2).

[0080] Table 2-1

[0081]

[0082]

[0083] Table 2-2

[0084]

[0085] The following can be known in combination with Table 2:

[0086] (1) It can be known from Formulas 2-6 and 9-10 that with the increase of the PCU amount, the mechanical properties, crystallization properties, water retention properties and field aging properties of the biodegradable mulch film are improved. Among them, the water retention properties and field aging properties are first improved with the increase of the PCU amount, and then decreased with the increase of the PCU amount, because the increase of the PCU amount causes the compatibility problems between the raw materials to gradually appear, thereby causing the decrease of the water retention properties and field aging properties. Therefore, when the PCU amount is 20wt%, the comprehensive performance is best.

[0087] (2) It can be known from the comparison of Formulas 1-2 that the addition of barium sulfate can improve the properties of the biodegradable mulch film, but the improvement effect is limited.

[0088] (3) It can be known from the comparison of Formulas 6-8 that compared with calcium carbonate and talc, barium sulfate has the most significant improvement effect on the biodegradable mulch film.

[0089] (4) It can be known from the comparison of the data of Formulas 1-2 and 6-8 that the combination of PCU and barium sulfate produces a synergistic effect, and significantly improves the water retention properties, field aging properties and the like of the full biodegradable mulch film.

[0090] Therefore, in the PBAT / PLA full biodegradable mulch film formula, the addition of PCU and nano barium sulfate whiskers in different proportions can significantly synergistically improve the mechanical properties, crystallization properties, water retention properties and field aging properties of the full biodegradable mulch film, and further improve the yield of crops laid with the full biodegradable mulch film. Especially under the condition of 20% PCU and 4% nano barium sulfate whisker addition amount, the performance gain of the full biodegradable mulch film is best.

[0091] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification of the above embodiment according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A low water permeable, fully biodegradable mulch film, characterized by, Prepared with the following raw materials: PBAT, PLA, PCU, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, zinc stearate.

2. The low water permeable full biodegradable mulch film according to claim 1, wherein, The amount of PBAT is 57.5-82.5 parts by weight, the amount of PLA is 4-6 parts by weight, the amount of PCU is 5-30 parts by weight, the amount of barium sulfate is 3-5 parts by weight, the amount of epoxy chain extender 4468 is 0.4-0.6 parts by weight, the amount of antioxidant 168 is 0.2-0.3 parts by weight, the amount of antioxidant 1010 is 0.3-0.5 parts by weight, the amount of anti-hydrolysis agent 1010 is 0.4-0.6 parts by weight, the amount of hindered amine light stabilizer HS-326 is 0.4-0.6 parts by weight, the amount of ultraviolet absorber UV-360 is 0.4-0.6 parts by weight, the amount of oxidized polyethylene wax is 0.2-0.3 parts by weight, and the amount of zinc stearate is 0.4-0.6 parts by weight.

3. The low water permeable full biodegradable mulch film according to claim 2, wherein, The amount of PBAT is 57.5-82.5 parts by weight, the amount of PLA is 5 parts by weight, the amount of PCU is 5-30 parts by weight, the amount of barium sulfate is 4 parts by weight, the amount of epoxy chain extender 4468 is 0.5 parts by weight, the amount of antioxidant 168 is 0.3 parts by weight, the amount of antioxidant 1010 is 0.4 parts by weight, the amount of anti-hydrolysis agent 1010 is 0.5 parts by weight, the amount of hindered amine light stabilizer HS-326 is 0.5 parts by weight, the amount of ultraviolet absorber UV-360 is 0.5 parts by weight, the amount of oxidized polyethylene wax is 0.3 parts by weight, and the amount of zinc stearate is 0.5 parts by weight.

4. The low water permeable full biodegradable mulch film according to claim 3, wherein, The amount of PCU is 20 parts by weight, and the amount of barium sulfate is 4 parts by weight.

5. The method of producing a low water permeable full-biodegradable mulch film according to any one of claims 1 to 4, characterized by, Comprising the following steps: (1) PBAT, PLA5, PCU5-30, barium sulfate, epoxy chain extender 4468, antioxidant 168, antioxidant 1010, anti-hydrolysis agent 1010, hindered amine light stabilizer HS-326, ultraviolet absorber UV-360, oxidized polyethylene wax, zinc stearate are stirred at 70-80°C, and then uniformly mixed to obtain material 1; (2) The material 1 is melt-extruded through a high-torque double-screw extruder, and then cooled to obtain material 2; (3) The material 2 is blown into a film to obtain the low water permeable full biodegradable mulch film.

6. The preparation method according to claim 5, wherein, The step (1) is stirred at 75℃ for 10-20 min.

7. The preparation method of claim 5, wherein, The step (2) is melt extruded at 155℃, 160℃, 165℃, 170℃, 175℃, 175℃, 175℃, 170℃, 165℃, 165℃ from the first section to the tenth section, the extruder feeding current is 5Hz, and the rotating speed is 160rpm.

8. The preparation method of claim 5, wherein, The step (3) is blown by a film blowing machine, and the temperature of the first zone to the fifth zone is 145℃, 150℃, 155℃, 160℃, 160℃.

9. The preparation method of claim 5, wherein, The step (3) is blown at a blow-up ratio of 3.2:1.

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