Special full-biodegradable mulching film beneficial to garlic growth and preparation method thereof

Abstract

The invention discloses a raw material composition of a special full-biodegradable mulching film beneficial to garlic growth. The raw material composition comprises the following components in parts by weight: 60-95 parts of biodegradable resin, 2-15 parts of lignin, 5-25 parts of mineral powder and 2.2-18 parts of auxiliaries, wherein the auxiliaries comprise the following components in parts by weight: 1-7 parts of a blocking agent, 0.2-2 parts of a plasticizer, 0.2-2 parts of a cross-linking agent, 0.2-1.5 parts of a chain extender, 0.2-3 parts of an antibacterial agent, 0.2-1.5 parts of an ultraviolet absorbent and 0.2-3 parts of a dispersing agent. The invention further provides a preparation method of the special full-biodegradable mulching film beneficial to garlic growth. The special full-biodegradable mulching film beneficial to garlic growth prepared by the method disclosed by the invention can ensure garlic seedling emergence and film breakage in the early stage, and can effectively control weeds; the mulching film gradually changes from brown to white in the middle stage, and the heat preservation requirement of garlic overwintering is met; due to the addition of various functional aids, the water retention capacity, the antibacterial property, the mechanical property and the like of the ultrathin degradable mulching film are improved, the function of the garlic in the growth cycle is not damaged, the growth rule of the garlic is further fitted, and the yield of the garlic is increased.

Description

Technical Field

[0001] The invention relates to the field of degradable composite materials, and in particular to a special fully biodegradable mulch film which is beneficial to the growth of garlic and a preparation method thereof. Background Art

[0002] The temperature in northern my country is relatively low in winter, and garlic planted in the open field is easily affected by frost and drought, resulting in reduced production. Mulch covering has the functions of increasing temperature and retaining moisture, resisting drought and saving water, and improving fertility, which significantly promotes its growth and development. Studies have shown that for many years, traditional agricultural polyethylene mulch coverings have not been degraded. In addition, most agricultural production uses substandard PE mulch products with a thickness of 4 to 6 μm sold on the market, which are difficult to recycle. The residual film seriously affects the decomposition of soil humus and the air permeability and water permeability, resulting in the destruction of soil structure, which in turn affects the balance of my country's farmland ecosystem. The research and development of fully biodegradable mulch provides an effective way to solve these problems.

[0003] Biodegradable mulch is a new type of mulch that can be degraded by microorganisms in the soil under natural environmental conditions and will not cause soil pollution. The biodegradable mulch currently used for garlic cultivation has the following main problems: (1) Garlic has a long growth period. The use of biodegradable mulch with the same thickness as PE (4-6 μm) has a short functional life cycle, severe degradation in the later stage, and the heat preservation and moisture retention function cannot meet the needs of crop growth; (2) Compared with PE mulch, the film breaking rate of thicker garlic is lower, and it needs to be broken manually, which is time-consuming and labor-intensive; (3) At present, most of the garlic mulch used in agriculture on the market is white. White mulch has a good heat preservation effect due to its high transparency, and the ground temperature rises quickly, and it also has a certain moisture retention effect. However, because it is light-transmitting, it is easy to breed weeds. Black mulch can effectively prevent the evaporation of water in the soil, maintain soil moisture, and inhibit the growth of weeds. However, due to its low light transmittance and slow temperature increase, it is not conducive to the growth and development of garlic, resulting in reduced production. The garlic mulch films in patents CN1177447849 and CN117322266 are both white mulch films, which have no weed control effect in the early stage. When there are many weeds, the film is damaged faster, resulting in a shortened functional period of the film. In addition, there are no functional additives, and the winter insulation effect of the mulch film cannot be guaranteed.

[0004] Therefore, the art urgently needs to develop a raw material that is widely available, green, environmentally friendly and completely biodegradable. At the same time, for garlic planting, it can solve the problems of low film breakage rate and effective weed control in the early stage, and meet the heat preservation and moisture retention function required by crops in the later stage, thereby increasing garlic yield. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a special fully biodegradable mulch film which is beneficial to the growth of garlic and has a thickness of less than 6 μm. The mulch film not only has mechanical properties comparable to those of PE mulch film, but can also control weeds in the early stage of garlic growth, keep heat and moisture in the middle and late stages, and degrade and break after harvest, thus saving labor costs such as peeling and picking up the film, and can also increase garlic yield.

[0006] The solution of the present invention is specifically as follows.

[0007] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, wherein the weight proportions of the components are: 60 to 95 parts of biodegradable resin, 2 to 15 parts of lignin, 5 to 25 parts of mineral powder, and 2.2 to 18 parts of additives;

[0008] The weight proportions of the auxiliary agents are: 1 to 7 parts of barrier agent, 0.2 to 2 parts of plasticizer, 0.2 to 2 parts of cross-linking agent, 0.2 to 1.5 parts of chain extender, 0.2 to 3 parts of antibacterial agent, 0.2 to 1.5 parts of ultraviolet absorber, and 0.2 to 3 parts of dispersant;

[0009] Wherein, the chain extender is KL-E4370 and KL-E4370B;

[0010] The antibacterial agent is one or more of benzethonium chloride and cetylpyridinium chloride;

[0011] The ultraviolet absorber is one or more of UV-531, UV-418, UV-419, and VSU-312.

[0012] Preferably, the biodegradable resin includes one or more of PBAT and PLA.

[0013] Preferably, the lignin comprises waste conventionally generated in the papermaking process, which is obtained by washing, drying, crushing and screening.

[0014] Preferably, the mineral powder includes one or more of talc and calcium carbonate.

[0015] Preferably, the weight proportions of the auxiliary agents are: 3 to 7 parts of barrier agent, 0.5 to 2 parts of plasticizer, 0.5 to 2 parts of cross-linking agent, 0.5 to 1.5 parts of chain extender, 0.5 to 3 parts of antibacterial agent, 0.3 to 1.5 parts of ultraviolet absorber, and 0.5 to 3 parts of dispersant.

[0016] More preferably, the weight proportions of the auxiliary agents are: 4 to 7 parts of barrier agent, 0.5 to 1.5 parts of plasticizer, 0.5 to 1.5 parts of cross-linking agent, 0.5 to 1 part of chain extender, 0.5 to 1 part of antibacterial agent, 0.3 to 1 part of ultraviolet absorber, and 0.5 to 1.5 parts of dispersant.

[0017] Preferably, the chain extender is KL-E4370B; the ultraviolet absorber is one or more of UV-531, UV-418, and UV-419.

[0018] Preferably, the barrier includes one or more of mica flakes, micron- or nano-sized montmorillonite, micron- or nano-sized attapulgite, micron- or nano-sized kaolin, and modified nano-silica; more preferably, the barrier is one or more of micron- or nano-sized montmorillonite, micron- or nano-sized attapulgite.

[0019] Preferably, the plasticizer includes one or more of TBC, ATBC, DOP, glycerol, and epoxidized soybean oil; more preferably, the plasticizer is one or more of ATBC, DOP, and glycerol.

[0020] Preferably, the cross-linking agent comprises one or more of BIBP, ADR4368 and ADR4370.

[0021] Preferably, the dispersant includes one or more of stearic acid, erucamide, ethylene bisstearamide, and oleamide; more preferably, the dispersant is stearic acid or erucamide.

[0022] The present invention also provides a method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, and the specific steps include:

[0023] S1, putting the biodegradable resin and the plasticizer into a high-speed blender and mixing them evenly to obtain a primary blend 1, and then putting the lignin, mineral powder and other additives into the blender and mixing them evenly to obtain a primary blend 2;

[0024] S2, placing the primary mixture 2 in a silo of a co-rotating twin-screw extruder, and extruding and granulating to obtain a masterbatch;

[0025] S3, forming the master batch by co-extrusion blown film to obtain the special fully biodegradable mulch film that is beneficial to the growth of garlic.

[0026] Preferably, the mixing time of step S1 is 20min-500min, the mixing speed is 10-4000rpm, and the mixing temperature is 20-120°C; more preferably, the mixing time of step S1 is 80-300min, the mixing speed is 200-3000rpm, and the mixing temperature is 50-120°C; optimally, the mixing time of step S1 is 100-200min, the mixing speed is 500-1000rpm, and the mixing temperature is 60-80°C.

[0027] Preferably, in the step S2, the temperature of zone one to zone ten is 50-180°C, the head temperature is 120-190°C, and the rotation speed is 30-500rpm; more preferably, in the step S2, the temperature of zone one to zone ten is 100-175°C, the head temperature is 130-185°C, and the rotation speed is 100-400rpm; optimally, in the step S2, the temperature of zone one to zone ten is 120-170°C, the head temperature is 155-185°C, and the rotation speed is 130-250rpm.

[0028] Preferably, the film blowing bag making temperature in step S3 is 120-190°C, more preferably 130-175°C, and most preferably 140-170°C.

[0029] A special fully biodegradable mulch film beneficial to the growth of garlic is prepared according to the preparation method.

[0030] Preferably, the ground film is brown, has a thickness of less than 6 μm, and a service life of more than 6 months.

[0031] The reagents and raw materials used in the present invention are commercially available.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1) In the present invention, the process route is simple, the product is green and environmentally friendly, has good stability, and can be self-degraded, which plays a good role in alleviating white pollution and protecting soil.

[0034] 2) In the present invention, the processing technology is improved, and the synergistic effect of lignin and antibacterial agent is added, so that the antibacterial performance is significantly enhanced and the antibacterial spectrum is wider; at the same time, the functional auxiliary agent ultraviolet absorber is added to protect the mulch film from being damaged by strong light and ultraviolet rays within a controllable time, and the thickness of the degraded mulch film is 5 μm, which can also ensure that the function of the garlic growth cycle within 6 months is not damaged, thereby solving the problem that the ultra-thin fully biodegradable mulch film is not suitable for garlic planting conditions.

[0035] 3) In the present invention, the addition of lignin (without black masterbatch) reduces the light transmittance of the mulch film to a certain extent, which can effectively control weeds in the early stage, reduce the amount of pesticides used, and thus reduce pesticide residues; in the later stage, the mulch film gradually fades with light exposure, and the mulch film becomes white, which meets the heat preservation needs of garlic overwintering.

[0036] 4) In the present invention, an inorganic barrier is added to improve the water retention performance of the mulch film, effectively inhibit the ineffective evaporation of soil moisture, increase the water storage and water return capacity of the soil, thereby improving the water utilization efficiency of the soil and meeting the moisture retention requirements of garlic on the mulch film.

[0037] 5) In addition, the present invention adds a cross-linking agent and a chain extender, which synergistically optimize each other to improve the mechanical properties of the ultra-thin degradable mulch film, ensuring that the process requirements of mechanical film laying can be met.

[0038] 6) The garlic-specific mulch prepared by the invention is not the black or white mulch on the market, but a brown mulch developed and prepared according to the growth habits of garlic and the growth and development rules of each stage. The main purpose of garlic seedling stage is to control weeds and prevent weeds from growing and competing with crops for nutrients. In the mid-term, the focus is on heat preservation. The mulch developed and prepared in this article can effectively control weeds in the early stage due to the addition of lignin with low transparency; in the mid-term, the lignin faded mulch gradually changes from brown to white, the light transmittance increases, and the ground temperature recovers quickly, meeting the heat preservation needs of garlic overwintering.

[0039] 7) The synergistic effect of various functional additives can better improve the water retention, antibacterial and mechanical properties of the ultra-thin degradable mulch film, ensure that the functions of garlic during the growth cycle are not damaged, further conform to the growth law of garlic, and greatly increase the yield of garlic. DETAILED DESCRIPTION

[0040] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0041] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention. The lignin used is the waste conventionally generated in the papermaking process, which is obtained by washing, drying, crushing and screening.

[0042] Example 1

[0043] A raw material composition of a special fully biodegradable mulch film beneficial to the growth of garlic, the types and amounts of its components are shown in Table 1.

[0044] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0045] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 60° C., the mixing speed is 500 rpm, and the mixing time is 150 min to obtain a primary mixture 2;

[0046] S2, and then placing the primary mixture 2 in a co-rotating twin-screw extruder for extrusion, plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 90°C, 115°C, 125°C, 135°C, 155°C, 160°C, 165°C, 167°C, 168°C and 168°C respectively; the head temperature of the twin-screw extruder is 168°C, and the screw speed is 130rpm;

[0047] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 168° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0048] Table 1

[0049] Raw material composition Specific types Weight parts / parts Biodegradable resin PBAT / PLA 80 / 8 Lignin / 7 Mineral powder talcum powder 5 Barrier Nano-montmorillonite 7 Plasticizers ATBC 0.5 Crosslinking agent ADR4368 0.3 Chain Extender KL-E4370B 0.3 Antimicrobial agents Benzethonium chloride 0.5 UV absorber UV-419 1 Dispersants Erucamide 1

[0050] Example 2

[0051] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 2.

[0052] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0053] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 80° C., the mixing speed is 600 rpm, and the mixing time is 160 min to obtain a primary mixture 2;

[0054] S2, placing the primary mixture in a co-rotating twin-screw extruder for extrusion, plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 100° C., 125° C., 135° C., 145° C., 155° C., 165° C., 165° C., 167° C., 170° C. and 170° C. respectively; the head temperature of the twin-screw extruder is 175° C., and the screw speed is 200 rpm;

[0055] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 169° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0056] Table 2

[0057] Raw material composition Specific types Weight parts / parts Biodegradable resin PBAT / PLA 70 / 10 Lignin / 15 Mineral powder talcum powder 5 Barrier Nano-grade attapulgite 5 Plasticizers DOP 1.2 Crosslinking agent ADR4370 0.9 Chain Extender KL-E4370B 0.8 Antimicrobial agents Cetylpyridinium chloride 0.7 UV absorber UV-418 0.8 Dispersants Stearic acid 1.2

[0058] Example 3

[0059] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 3.

[0060] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0061] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 70° C., the mixing speed is 700 rpm, and the mixing time is 180 min to obtain a primary mixture 2;

[0062] S2. The primary mixture is placed in a co-rotating twin-screw extruder for extrusion, plasticization and granulation to obtain a masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 110°C, 115°C, 135°C, 145°C, 155°C, 165°C, 165°C, 167°C, 168°C and 168°C respectively; the head temperature of the twin-screw extruder is 173°C, and the screw speed is 210rpm;

[0063] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 165° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0064] Table 3

[0065]

[0066]

[0067] Example 4

[0068] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 4.

[0069] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0070] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 75° C., the mixing speed is 550 rpm, and the mixing time is 180 min to obtain a primary mixture 2;

[0071] S2, placing the primary mixture in a co-rotating twin-screw extruder for extrusion, plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 90°C, 100°C, 115°C, 125°C, 155°C, 160°C, 160°C, 165°C, 166°C and 166°C respectively; the head temperature of the twin-screw extruder is 166°C, and the screw speed is 220rpm;

[0072] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 155° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0073] Table 4

[0074]

[0075]

[0076] Comparative Example 1

[0077] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 5.

[0078] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0079] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 80° C., the mixing speed is 150 rpm, and the mixing time is 180 min to obtain a primary mixture 2;

[0080] S2, placing the primary mixture in a co-rotating twin-screw extruder for plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 90°C, 100°C, 115°C, 125°C, 155°C, 160°C, 160°C, 165°C, 166°C and 166°C respectively; the head temperature of the twin-screw extruder is 166°C, and the screw speed is 270rpm;

[0081] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 155° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0082] Table 5

[0083]

[0084]

[0085] Comparative Example 2

[0086] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 6.

[0087] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0088] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 80° C., the mixing speed is 150 rpm, and the mixing time is 180 min to obtain a primary mixture 2;

[0089] S2, placing the primary mixture in a co-rotating twin-screw extruder for plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 90°C, 100°C, 115°C, 125°C, 155°C, 160°C, 160°C, 165°C, 166°C and 166°C respectively; the head temperature of the twin-screw extruder is 166°C, and the screw speed is 270rpm;

[0090] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 155° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0091] Table 6

[0092] Raw material composition Specific types Weight parts / parts Biodegradable resin PBAT / PLA 63 / 7 Lignin / 10 Mineral powder talcum powder 20 Barrier Mica Sheet 3 Plasticizers ATBC 1.5 Crosslinking agent ADR4370 0.5 Chain Extender KL-E4370B 2.5 Antimicrobial agents Cetylpyridinium chloride 0.5 UV absorber UV-418 0.5 Dispersants Erucamide 1.5

[0093] Comparative Example 3

[0094] A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, the types and amounts of its components are shown in Table 7.

[0095] A method for preparing a special fully biodegradable mulch film that is beneficial to the growth of garlic, the specific steps comprising:

[0096] S1, placing the raw material composition in a high-speed blender for mixing, the temperature of the two mixings is 70° C., the mixing speed is 700 rpm, and the mixing time is 180 min to obtain a primary mixture 2;

[0097] S2, placing the primary mixture in a co-rotating twin-screw extruder for extrusion, plasticization and granulation to obtain masterbatch; the temperatures of the extruder from zone 1 to zone 10 are 110°C, 115°C, 135°C, 145°C, 155°C, 165°C, 165°C, 167°C, 168°C and 168°C respectively; the head temperature of the twin-screw extruder is 173°C, and the screw speed is 210rpm;

[0098] S3, putting the masterbatch prepared above into a co-extrusion film blowing machine for film blowing molding, the film blowing molding temperature is 165° C., and a special fully biodegradable mulch film that is beneficial to the growth of garlic is prepared.

[0099] Table 7

[0100] Raw material composition Specific types Weight parts / parts Biodegradable resin PBAT / PLA 65 / 10 Lignin / 0 Filling Calcium carbonate 25 Barrier Nano-grade attapulgite 3 Plasticizers DOP 2 Crosslinking agent ADR436 1.5 Chain Extender KL-E4370B 0.3 Antimicrobial agents Benzethonium chloride 0.1 UV absorber UV-418 1.5 Dispersants Stearic acid 2

[0101] Comparative Example 4

[0102] Common white 0.005mm biodegradable mulch in the market.

[0103] Implementation effect:

[0104] 1. Experimental design

[0105] A total of 7 treatment groups were set up in the experiment. The 4 groups of biodegradable mulches of the embodiments were marked as (DM1, DM2, DM3 and DM4), and the 4 groups of comparative mulches were marked as CK1 (no chain extender and UV absorber added), CK2 (excessive addition of chain extender), CK3 (no lignin added, and the amount of antibacterial agent added was lower than the range described in the claims) and CK4 (ordinary PE mulch), as shown in Table 8.

[0106] Table 8

[0107] deal with Specific specifications color DM1 Example 1 0.005 mm biodegradable mulch film brown DM2 Example 2 0.005 mm biodegradable mulch film brown DM3 Example 3 0.005 mm biodegradable mulch film brown DM4 Example 4 0.005 mm biodegradable mulch film brown CK1 0.005 mm biodegradable mulch film of Comparative Example 1 brown CK2 0.005 mm biodegradable mulch film of Comparative Example 2 brown CK3 0.005 mm biodegradable mulch film of Comparative Example 3 White CK4 0.005mm ordinary PE mulch film of comparative example 4 White

[0108] Each treatment was repeated three times in a randomized block arrangement, with a total of 21 experimental plots, each of which was 2 meters wide, 5 meters long, and 10m in area. 2 , set up protective rows around. Sowing was done on October 15 and harvested on May 20. Artificial hole sowing was used. When sowing, the row spacing was set to 17cm and the plant spacing was 12cm. The bulbs were placed with the top bud facing up and the bulb plate facing down, and inserted directly into the soil. After sowing, the ridges were filled, watered with flooding and herbicides were sprayed. When the soil was semi-wet, the mulch was covered with film. The mulching method was full ridge covering. Watering was done twice during the growth cycle, before mulching and during the bolting period. Compound fertilizer (N:P 2 O:K 2 O is 25:15:15) 1300kg·hm -2 and 1000kg·hm -2 Except for the type of mulch, other field management measures were the same.

[0109] According to the method in the national standard GB / T6673, the ground films of the formulations in Examples 1-4 and Comparative Examples 1-4 were made into test specimens, and then the tensile strength and elongation of the above Examples and Comparative Examples were tested.

[0110] According to the five growth periods of garlic, namely the germination period, seedling period, green period, bolting period and bulb expansion period, the soil temperature and humidity at a depth of 10 cm were measured; after harvesting, the horizontal and vertical diameters of the garlic were measured, the weight of the fresh garlic was weighed, the yield of the plot was counted and converted to the yield per mu.

[0111] As shown in Table 9, the tensile strength of the prepared garlic-specific fully biodegradable mulch film is slightly higher than that of the PE film, and the elongation is equivalent to that of the PE film, which ensures the early emergence and film breaking rate of garlic, and the performance also meets the performance requirements of the national standard GBT 35795-2017 fully biodegradable agricultural ground covering film. After harvesting and plowing, the surface residue of the garlic-specific fully biodegradable mulch film is less than 15%, has no tensile strength, is easily torn by hand, and is in pieces. Ordinary PE mulch film has better toughness.

[0112] Table 9 Survey on performance of mulch film before and after use

[0113]

[0114]

[0115] As shown in Table 10, the four groups of mulch films prepared specifically for garlic have higher thermal insulation properties for the soil than PE films in the early stage, especially in the seedling and green stages, which are significantly higher than PE films. In the later stage, as the mulch films degrade, the thermal insulation properties of the degraded mulch films are slightly lower than those of the PE films.

[0116] Table 10 Changes in soil temperature under different mulch films

[0117] deal with Germination period / °C Seedling stage / ℃ Green period / ℃ Bolting period / ℃ Bulb expansion period / ℃ DM1 19.2 8.3 19.1 25.8 29.5 DM2 19.1 8.5 18.9 25.7 29.1 DM3 18.7 8.1 20.1 25.7 29.3 DM4 18.6 7.8 19.0 25.6 28.8 CK1 18.3 6.0 17.0 24.6 27.7 CK2 18.3 6.7 17.9 24.8 28.2 CK3 18.9 6.8 17.8 25.3 28.5 CK4 18.5 6.5 17.5 25.3 30.1

[0118] It can be seen from Table 11 that during the five periods of garlic growth, the four groups of garlic-specific mulch films had higher soil moisture retention in the early stage than CK1 (without adding chain extender and UV absorber), CK2 (without adding lignin and antibacterial agent) and CK3 (ordinary PE mulch film). In the later stage, as the mulch film degraded, the soil moisture retention was slightly lower than that of PE mulch film.

[0119] Table 11 Changes in soil moisture under different mulch films

[0120] deal with Germination period / % Seedling stage / % Green period / % Bolting period / % Bulb expansion period / % DM1 29.5 25.6 19.0 30.6 24.2 DM2 29.5 25.6 19.0 30.6 24.1 DM3 29.3 25.4 18.9 30.1 24.1 DM4 29.2 25.4 18.8 30.2 24.3 CK1 27.1 23.8 16.7 28.2 23.1 CK2 27.8 24.2 16.9 28.9 23.8 CK3 28.5 25.1 16.9 28.8 23.8 CK4 27.5 24.3 17.1 28.9 24.5

[0121] As shown in Table 12, the weed control ability of the four groups of mulches prepared for garlic is significantly better than that of the control mulches, and the weeds are effectively suppressed, saving the cost of manual weeding, reducing the amount of pesticides used, and thus reducing pesticide residues, while protecting the ecological environment. Compared with PE mulches, the prepared garlic mulches can significantly promote the growth and formation of garlic bulbs and increase yields.

[0122] Table 12 Survey on weeds and yield in the experimental plot

[0123]

[0124] It can be seen from the above results that the garlic-specific fully biodegradable mulch film of the present invention can effectively control weeds, has a tensile strength slightly higher than that of the PE film, and an elongation equivalent to that of the PE film, thereby ensuring the early garlic emergence and film breaking rate, while ensuring that the mechanical properties of the mulch film during the garlic growth cycle meet the requirements, and has better heat preservation and moisture retention properties, further conforms to the growth law of garlic, and is beneficial to increasing garlic production.

[0125] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A raw material composition of a special fully biodegradable mulch film that is beneficial to the growth of garlic, characterized in that: The weight proportions of the raw material components are: 60-95 parts of biodegradable resin, 2-15 parts of lignin, 5-25 parts of mineral powder, and 2.2-18 parts of additives; The weight proportions of the auxiliary agents are: 1 to 7 parts of barrier agent, 0.2 to 2 parts of plasticizer, 0.2 to 2 parts of cross-linking agent, 0.2 to 1.5 parts of chain extender, 0.2 to 3 parts of antibacterial agent, 0.2 to 1.5 parts of ultraviolet absorber, and 0.2 to 3 parts of dispersant; Wherein, the chain extender is one or more of KL-E4370 and KL-E4370B; The antibacterial agent is one or more of benzethonium chloride and cetylpyridinium chloride; The ultraviolet absorber is one or more of UV-531, UV-418, UV-419, and VSU-312.

2. The raw material composition of a special fully biodegradable mulch film beneficial to garlic growth as claimed in claim 1, characterized in that: The biodegradable resin includes one or more of PBAT and PLA; And / or, the lignin includes waste conventionally generated in the papermaking process, which is obtained by washing, drying, crushing and screening; And / or, the mineral powder includes one or more of talc and calcium carbonate.

3. The raw material composition of a special fully biodegradable mulch film beneficial to garlic growth as claimed in claim 1, characterized in that: The weight proportions of the auxiliary agents are: 3 to 7 parts of barrier agent, 0.5 to 2 parts of plasticizer, 0.5 to 2 parts of cross-linking agent, 0.5 to 1.5 parts of chain extender, 0.5 to 3 parts of antibacterial agent, 0.3 to 1.5 parts of ultraviolet absorber and 0.5 to 3 parts of dispersant.

4. The raw material composition of a special fully biodegradable mulch film beneficial to garlic growth as claimed in claim 1, characterized in that: The chain extender is KL-E4370B; the ultraviolet absorber is one or more of UV-531, UV-418 and UV-419.

5. The raw material composition of a special fully biodegradable mulch film beneficial to garlic growth as claimed in claim 1, characterized in that: The barrier agent includes one or more of mica flakes, micron-sized or nano-sized montmorillonite, micron-sized or nano-sized attapulgite, micron-sized or nano-sized kaolin, and modified nano-silicon dioxide; And / or, the plasticizer includes one or more of TBC, ATBC, DOP, glycerol, and epoxidized soybean oil; And / or, the cross-linking agent includes one or more of BIBP) ADR4368, ADR 4370; And / or, the dispersant includes one or more of stearic acid, erucamide, ethylene bisstearamide, and oleamide.

6. A method for preparing a special fully biodegradable mulch film beneficial to garlic growth as claimed in any one of claims 1 to 5, characterized in that: The specific steps include: S1, putting the biodegradable resin and the plasticizer into a high-speed blender and mixing them evenly to obtain a primary blend 1, and then putting the lignin, mineral powder and other additives into the blender and mixing them evenly to obtain a primary blend 2; S2, placing the primary mixture 2 in a silo of a co-rotating twin-screw extruder, and extruding and granulating to obtain a masterbatch; S3, forming the master batch by co-extrusion blown film to obtain the special fully biodegradable mulch film that is beneficial to the growth of garlic.

7. The method for preparing a special fully biodegradable mulch film beneficial to the growth of garlic as claimed in claim 6, characterized in that: The mixing time of step S1 is 20 min-500 min, the mixing speed is 10-4000 rpm, and the mixing temperature is 20-120° C.; In step S2, the temperature of zones 1 to 10 is 50-180°C, the temperature of the die is 120-190°C, and the rotation speed is 30-500 rpm; The film blowing bag making temperature in step S3 is 120-190°C.

8. A special fully biodegradable mulch film that is beneficial to the growth of garlic, characterized in that: It is prepared according to the preparation method described in any one of claims 6 to 7.

9. A special fully biodegradable mulch film beneficial to the growth of garlic as claimed in claim 8, characterized in that: The ground film is brown, has a thickness of less than 6 μm, and has a service life of more than 6 months.

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