CN106519603A - Biodegradable weeding mulching film, and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of agricultural films, and discloses a biodegradable weeding film and a preparation method thereof. The mulch film of the present invention comprises the following components in mass percentage: biodegradable resin A 70-97%; biodegradable herbicide masterbatch 3-30%; Mix with 0.5-7% surfactant A, activate by ultrasonic; then mix with 25-75% biodegradable resin B, 1-10% surfactant B at high speed, extrude and granulate to obtain herbicide masterbatch, the surfactant used The mass ratio of agent A (hydrophilic-lipophilic balance value 7-10) to surfactant B (hydrophilic-lipophilic balance value 3-6) is 1:1-1:2. The invention adopts surfactants with different balance values of hydrophilic and lipophilic as the wetting and dispersing agent of the herbicide and the compatibilizer with the resin to effectively improve the compatibility of the herbicide and the resin.

Description

A kind of biodegradable weeding film and preparation method thereof

technical field

The invention belongs to the technical field of agricultural films, in particular to a biodegradable weeding film and a preparation method thereof.

Background technique

Weed-killing mulch is a functional mulch product with weed-killing effect prepared by adding herbicides to plastic films. During the use of the mulch film, the herbicide diffuses to the surface of the mulch film to form a herbicidal molecular layer, which dissolves and drips to the ground together with the water droplets attached to the surface of the mulch film, and is absorbed by the soil to form a herbicide treatment layer with a certain concentration, which finally achieves the purpose of inhibiting the growth of weeds, And the purpose of causing weed death. Compared with the traditional spraying method, adding herbicides to plastic films to prepare herbicide mulches can reduce the loss of herbicides in the process of spraying, and by improving the utilization rate of herbicides, the amount of herbicides can be reduced and Targeted herbicide; it can reduce the release rate, so that the herbicide can be released continuously for a long time and prolong the efficacy period; it is a new type of special herbicide dosage form, which can reduce the harm of herbicide to humans and animals during use. In view of major problems such as excessive release of herbicide active ingredients, short duration of drug effect, and serious ecological pollution, herbicide mulch technology is a good way to overcome these problems and has broad market prospects. However, most of the current weed-killing mulches use non-degradable polyethylene as the carrier, which is prepared after mixing with herbicides, and does not have the function of complete biodegradation. If it is used year after year, it will cause serious white pollution problems to the soil and the environment, and cause Soil compaction, poor permeability, hindered root growth, and subsequent crop yield reduction.

Biodegradable weed-killing mulch film is prepared by mixing herbicide or herbicide masterbatch with fully biodegradable polymer resin with fully biodegradable polymer resin as the carrier. It has the functions of biodegradation and weed control. It is an environment-friendly functional mulch product. Since the currently commercially available herbicides are all small molecule compounds, and most of them have certain polarity, the compatibility of these small molecule herbicides with fully biodegradable polymer resins is poor, resulting in The release rate of the herbicide is fast and the drug effect time is short. Chinese invention patent (CN201210525950.7) "a fully biodegradable agricultural weeding mulch" uses a mixer to mix the biodegradable resin, herbicide, chain extender, and release agent evenly, and then uses a twin-screw extruder to blend The final material is extruded, modified, granulated, and then film-drawn by a film-drawing machine. This technology does not solve the compatibility problem between herbicides and biodegradable polymer resins; Chinese invention patent (CN102276966A) "biologically Decomposition of weed-removing mulch masterbatch, preparation method of weed-killing mulch "in the method of adding a coupling agent to the mixture of herbicides and degradable polymer resins to prepare herbicide masterbatches. improvement is limited. The herbicide mulch film prepared by the prior art has problems such as too fast herbicide release speed, short herbicide efficacy, and poor weeding effect during use, which affects the application and promotion of the mulch film.

Contents of the invention

In order to overcome the shortcomings and deficiencies of the above-mentioned prior art, the primary purpose of the present invention is to provide a biodegradable weeding mulch film.

Another object of the present invention is to provide a preparation method of the biodegradable weeding mulch film.

The object of the present invention is achieved through the following solutions:

A biodegradable weeding mulch film, comprising the following components in mass percentage:

Biodegradable herbicide masterbatch 3～30%

Biodegradable resin A 70-97%;

Described biodegradable herbicide masterbatch is prepared by the method comprising the following steps:

The herbicide is mixed with surfactant A, activated by ultrasonic; then mixed with biodegradable resin B and surfactant B at high speed, extruded and granulated to obtain herbicide masterbatch.

In the above-mentioned preparation method, the mass percent of each reactant is as follows:

The mass ratio of the surfactant A to the surfactant B is 1:1˜1:2.

The surfactant A is a surfactant with a hydrophilic-lipophilic balance value of 7-10.

The surfactant B is a surfactant with a hydrophilic-lipophilic balance value of 3-6.

The surfactant with the hydrophilic-lipophilic balance value of 7 to 10 is preferably sorbitan laurate, polyoxyethylene lauryl ether, polyoxyethylene (4EO) sorbitan monostearate, poly At least one of oxypropylene mannitol dioleate, polyoxyethylene oxypropylene oleate, polyoxypropylene stearate and hexaethylene glycol monostearate.

The surfactant with a hydrophilic-lipophilic balance value of 3 to 6 is preferably propylene glycol fatty acid ester, propylene glycol monostearate, glyceryl monostearate, sorbitan monooleate, propylene glycol monolaurate At least one of esters, diethylene glycol fatty acid esters and sorbitan monopalmitate.

The biodegradable herbicide masterbatch of the present invention is prepared by modifying a surfactant. Among them, the surfactant used is composed of a series of non-ionic surfactants with a hydrophilic-lipophilic balance value of 3 to 10, wherein the non-ionic surfactant with a hydrophilic-lipophilic balance value of 7-10 is used as a wetting agent. The dispersant can effectively improve the wetting and dispersibility of the herbicide; the non-ionic surfactant with a hydrophilic-lipophilic balance value of 3-6 is used as a compatibilizer to effectively improve the compatibility of the herbicide and the resin.

The molecular structure of surfactants includes two parts: long-chain hydrophobic groups and hydrophilic ionic groups or polar groups. The special molecular structure of the surfactant makes it have wetting and solubilizing effects in the application process. Therefore, choosing a surfactant with a certain polarity similar to the herbicide molecule and the biodegradable polymer resin can improve the interfacial compatibility between the herbicide molecule and the biodegradable polymer resin matrix.

The herbicide used is preferably a pre-emergent herbicide, more preferably acetochlor, pretilachlor, butachlor, metolachlor, isoproturon, atrazine, promethazone, ametrazine, and ametrione and at least one of hexazinone.

The biodegradable resin B can be the same as or different from the biodegradable resin A, and is preferably poly(butylene adipate-butylene terephthalate) (PBAT) with a particle size of 60-200 mesh.

Preferably, the biodegradable herbicide masterbatch also contains 1-5 wt% of processing aids.

The processing aid refers to at least one of lubricant, dispersant and antioxidant.

The mixing is preferably performed in a mixer for 3-5 minutes.

The ultrasonic activation is preferably performed under the power of 100-500W for 3-25 minutes. The activation is to use the energy generated by the ultrasonic wave to enhance the reactivity between the polar functional group of the herbicide and the polar or weakly polar functional group in the surfactant, thereby utilizing the surface activity with a hydrophilic-lipophilic balance value of 7-10 It can effectively improve the wetting and dispersibility of herbicides.

The high-speed mixing is preferably stirring and mixing at a rate of 600-1200 rpm for 1-5 minutes, and the mixing temperature does not exceed 60°C.

The temperature of each section of the extrusion granulation is 110-150°C.

During the above-mentioned high-speed mixing process, processing aids such as at least one of lubricants, dispersants and antioxidants may be added.

In the biodegradable weeding film of the present invention:

The biodegradable resin A is preferably at least one of polylactic acid (PLA) and poly(butylene adipate-butylene terephthalate) (PBAT).

Preferably, the melt index of the PLA used is 3-5 g/10 min; the amount of the PLA used is 10-35 wt% of the total amount of the biodegradable resin A.

Preferably, the melt index of the PBAT used is 3-5 g/10 min; the amount of the PBAT used is 65-90 wt% of the total amount of the biodegradable resin A.

Preferably, the biodegradable weed-killing mulch may also contain light stabilizers, ultraviolet absorbers, antioxidants and the like.

The present invention also provides a preparation method of the above-mentioned biodegradable weeding film, comprising the following specific steps:

The biodegradable herbicide masterbatch and the biodegradable resin A are uniformly mixed in proportion, and then blow-molded to obtain a biodegradable weed-killing mulch film.

Said mixing refers to mixing in a mixer for 3-5 minutes.

The temperature of each section of the blow molding process is 130-200°C.

During the above mixing process, light stabilizers, ultraviolet absorbers and antioxidants may be added.

Application of the biodegradable weeding mulch film of the present invention in crop planting.

Mechanism of the present invention is:

The present invention uses a series of non-ionic surfactants with a hydrophilic-lipophilic balance value of 3 to 10 as modifiers, wherein the different polar parts in the molecular chain of the modifier have a certain polarity with the herbicide molecule and the biodegradable resin respectively. Therefore, by selecting a nonionic surfactant with a hydrophilic-lipophilic balance value of 7 to 10, the wetting and dispersibility of the herbicide can be increased, and the dispersion uniformity of the herbicide in the biodegradable polymer resin matrix can be improved; by selecting Nonionic surfactants with a hydrophilic-lipophilic balance of 3 to 6 increase the interfacial compatibility between the herbicide molecule and the biodegradable polymer resin matrix, increase its interfacial binding force, and thus increase the duration of herbicide efficacy.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) In the herbicide masterbatch of the present invention, a series of nonionic surfactants with a hydrophilic-lipophilic balance value of 3 to 10 are used as interface modifiers between the herbicide and the biodegradable resin, and are enhanced by ultrasonic technology Activation, the compatibility of the herbicide and the biodegradable resin is significantly improved, and the interaction force is enhanced.

(2) the present invention has used the herbicide masterbatch that the nonionic surfactant pretreatment of hydrophilic-lipophilic balance value is 7～10, can make herbicide evenly disperse in the plastic film, make the herbicide and biodegradable resin The compatibility is improved and the interaction force is enhanced, so that the release rate of the herbicide is slowed down, the drug effect time is prolonged, the utilization rate and utilization efficiency of the herbicide are effectively improved, and the groundwater pollution caused by the loss of the herbicide is reduced. After 60 days, the weeding effect can still reach more than 90%.

detailed description

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

All reagents used in the following examples are available from commercial sources.

Example 1

Preparation of biodegradable herbicide masterbatch:

Mix atrazine with sorbitan laurate for 3 to 5 minutes, and ultrasonically activate it at 100 to 500 W for 3 to 25 minutes; then mix it with PBAT and glyceryl monostearate, and stir and mix at 600 to 1200 rpm for 1 ～5min, the mixing temperature does not exceed 60°C, extruding and granulating at 110～150°C to obtain the herbicide masterbatch.

Wherein, the mass percentages of each reactant are: PBAT 75%; atrazine 20%; sorbitan laurate 2.5%; glyceryl monostearate 2.5%.

Preparation of biodegradable weeding mulch film:

Mix the biodegradable herbicide masterbatch with PLA and PBAT in a mixer for 3-5 minutes, and blow molding at 130-200°C to obtain a biodegradable herbicide mulch film.

Wherein, the mass percentage of each reactant is: 30% of biodegradable herbicide masterbatch; 10% of PLA; 60% of PBAT.

The melt index of PLA used is 3-5g/10min; the melt index of PBAT used is 3-5g/10min.

Example 2

Preparation of biodegradable herbicide masterbatch:

Mix atrazine with polyoxyethylene lauryl ether for 3 to 5 minutes, ultrasonically activate at 100 to 500 W for 3 to 25 minutes; then mix with PBAT and propylene glycol fatty acid ester, stir and mix at 600 to 1200 rpm for 1 to 5 minutes, and mix The temperature does not exceed 60°C, extruded and granulated at 110-150°C to obtain herbicide masterbatch.

Wherein, the mass percent of each reactant is: PBAT 75%; atrazine 10%; polyoxyethylene lauryl ether 5%; propylene glycol fatty acid ester 10%.

Preparation of biodegradable weeding mulch film:

Mix the biodegradable herbicide masterbatch with PLA and PBAT in a mixer for 3-5 minutes, and blow molding at 130-200°C to obtain a biodegradable herbicide mulch film.

Wherein, the mass percentage of each reactant is: 10% of biodegradable herbicide masterbatch; 15% of PLA; 75% of PBAT.

The melt index of PLA used is 3-5g/10min; the melt index of PBAT used is 3-5g/10min.

Example 3

Preparation of biodegradable herbicide masterbatch:

Mix atrazine with polyoxyethylene (4EO) sorbitan monostearate for 3 to 5 minutes, and ultrasonically activate it for 3 to 25 minutes at a power of 100 to 500 W; then mix it with PBAT and propylene glycol monostearate, and Stirring and mixing at 600-1200 rpm for 1-5 minutes, the mixing temperature does not exceed 60°C, extruding and granulating at 110-150°C to obtain the herbicide masterbatch.

Wherein, the mass percent of each reactant is: PBAT 30%; atrazine 60%; polyoxyethylene (4EO) sorbitan monostearate 5%; propylene glycol monostearate 5%.

Preparation of biodegradable weeding mulch film:

Mix the biodegradable herbicide masterbatch with PLA and PBAT in a mixer for 3-5 minutes, and blow molding at 130-200°C to obtain a biodegradable herbicide mulch film.

Wherein, the mass percentage of each reactant is: 3% of biodegradable herbicide masterbatch; 20% of PLA; 77% of PBAT.

The melt index of PLA used is 3-5g/10min; the melt index of PBAT used is 3-5g/10min.

Example 4

Preparation of biodegradable herbicide masterbatch:

Mix atrazine with polyoxypropylene mannitol dioleate and polyoxyethylene oxypropylene oleate for 3 to 5 minutes, and ultrasonically activate it at 100 to 500 W for 3 to 25 minutes; then mix with PBAT and sorbitan monooleate Ester and propylene glycol monolaurate were mixed, stirred and mixed at 600-1200 rpm for 1-5 minutes, the mixing temperature did not exceed 60°C, and extruded at 110-150°C to obtain herbicide masterbatches.

Wherein, the mass percent of each reactant is: PBAT 25%; Atrazine 60%; Polyoxypropylene mannitol dioleate 2.5%; Polyoxyethylene oxypropylene oleate 2.5%; Esters 5%; Propylene Glycol Monolaurate 5%.

Preparation of biodegradable weeding mulch film:

Mix the biodegradable herbicide masterbatch with PLA and PBAT in a mixer for 3-5 minutes, and blow molding at 130-200°C to obtain a biodegradable herbicide mulch film.

Wherein, the mass percentage of each reactant is: 10% of biodegradable herbicide masterbatch; 30% of PLA; 60% of PBAT.

The melt index of PLA used is 3-5g/10min; the melt index of PBAT used is 3-5g/10min.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplification should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. a kind of biodegradation weed removal mulch film, it is characterised in that the component comprising following mass percent：

Biodegradable herbicide master batch 3～30%

Biodegradable resin A 70～97%；

Described biodegradable herbicide master batch is prepared by the method for comprising the following steps：

Herbicide is mixed with surfactant A, ultrasonic activation；Again with Biodegradable resin B, surfactant B mixed at high speed, Extruding pelletization, obtains Herbicide master batch；

In above-mentioned preparation method, the mass percent of each reactant is as follows：

The surfactant A is 1 with the mass ratio of surfactant B:1～1:2；

Described surfactant A is surfactant that hydrophile-lipophile balance value is 7～10；

Described surfactant B is surfactant that hydrophile-lipophile balance value is 3～6.

2. biodegradation weed removal mulch film according to claim 1, it is characterised in that：Described hydrophile-lipophile balance value is 7 ～10 surfactant is anhydrous sorbitol laurate, polyoxyethylene laurel ether, polyoxyethylene sorbitan list Hard Fat Acid esters, polyoxypropylene Mannitol dioleate, polyoxyethylene oxypropylene oleate, polyoxypropylene stearate and six ethylene glycol lists At least one in stearate.

3. biodegradation weed removal mulch film according to claim 1, it is characterised in that：Described hydrophile-lipophile balance value is 3 ～6 surfactant is methyl glycol fatty acid ester, propylene glycol monostearate, glyceryl monostearate, anhydrous sorbitol list At least one in oleate, PGML, diethylene glycol fatty acid ester and sorbitan monopalmitate.

4. biodegradation weed removal mulch film according to claim 1, it is characterised in that：Herbicide used is Acetochlor, third careless At least one in amine, butachlor, isopropyl methoxalamine, isoproturon, atrazine, prometryn, ametryn, metribuzin and hexazinone.

5. biodegradation weed removal mulch film according to claim 1, it is characterised in that：Described Biodegradable resin A is poly- At least one in lactic acid and poly- (tetramethylene adipate-mutual-phenenyl two acid bromide two alcohol ester)；Described Biodegradable resin B is Poly- (tetramethylene adipate-mutual-phenenyl two acid bromide two alcohol ester).

6. biodegradation weed removal mulch film according to claim 1, it is characterised in that：The biodegradable herbicide master batch is also Processing aid containing 1～5wt%.

7. biodegradation weed removal mulch film according to claim 1, it is characterised in that：In the biodegradation weed removal mulch film also Containing at least one in light stabilizer, UV absorbent and antioxidant.

8. biodegradation weed removal mulch film according to claim 1, it is characterised in that：Described being mixed into is mixed in mixer Close 3～5min；Described ultrasonic activation is 3～25min of ultrasound under 100～500W power；Described mixed at high speed is 600 1～5min of stirring mixing under～1200rpm speed, the temperature of mixing are less than 60 DEG C；Each section of temperature of the extruding pelletization be 110～150 DEG C.

9. the preparation method of the biodegradation weed removal mulch film described in a kind of any one of claim 1～8, it is characterised in that comprising with Lower concrete steps：After in proportion mixed homogeneously biodegradable herbicide master batch with Biodegradable resin A, blowing processing is obtained Biodegradation weed removal mulch film.

10. the preparation method of biodegradation weed removal mulch film according to claim 9, it is characterised in that：Described mixing refers to Mix 3～5min in mixer；Each section of temperature of the blowing processing is 130～200 DEG C.