CN108485207A - Fully-degradable mulching film with phosphate fertilizer slow-release effect and preparation method thereof - Google Patents

Abstract

The invention discloses a fully degradable mulch film with the effect of slow-release phosphate fertilizer and a preparation method thereof, which is characterized in that the film is blown by blending phosphating-modified lignin and completely biodegradable plastics to obtain a fully biodegradable slow-release phosphate fertilizer Degrades mulch. The invention effectively utilizes renewable lignin resources, reduces the consumption of petroleum-based raw materials in the preparation of mulch, and reduces the environmental pollution problems caused by the biorefining industry and non-degradable mulch. Phosphated lignin is used as a slow-release phosphate fertilizer for crops It also helps to improve the utilization rate of phosphorus fertilizer and improve the soil, so it has good environmental, resource and economic benefits.

Description

A fully degradable mulch film with slow-release phosphate fertilizer effect and preparation method thereof

technical field

The invention belongs to the field of agricultural films, and in particular relates to a fully degradable film with the effect of slow-release phosphate fertilizer and a preparation method thereof.

Background technique

The development of degradable plastic film is currently the main direction to solve the problem of plastic film pollution in the world. The use of degradable plastic film saves the link of recycling and processing residual film, which brings great convenience to agricultural production. The traditional degradable mulch is made of polyethylene (PE) composite photodegradant, starch, etc. It can disintegrate into mulch fragments within a certain period of time, but the mulch fragments are mainly composed of refractory PE, and these fragments will exist in the soil for a long time Therefore, the development of fully degradable mulch has become a research hotspot at home and abroad. A variety of polyester plastics such as polybutylene terephthalate/adipate (PBAT), polylactic acid (PLA), polypropylene carbonate (PPC), polysuccinate/adipate Ester (PBSA), polyhydroxyalkanoate (PHA), polybutylene succinate (PBS), etc. have been proved to have complete biodegradability, and can be decomposed by enzymes in various microorganisms, animals and plants under natural conditions. Catabolism produces carbon dioxide and water. However, compared with traditional mulch, the mulch made of this type of plastic has low strength, poor toughness, and high cost, which hinders its large-scale application to the market.

Lignin is the natural aromatic polymer with the largest reserves in plants. As a by-product of biorefinery and papermaking industry, lignin has multiple advantages such as cheap, easy to obtain, biodegradable, and easy to derivatize. However, less than 2% of industrial lignin The lignin is recycled, and the rest of the large amount of lignin is burned or discarded, resulting in a large amount of waste of resources and environmental pollution. However, lignin itself has the effect of soil improvement and plant preservation, and can be converted into high value-added products for use in the field of agricultural and forestry production. When lignin is modified with the fertilizer elements needed for crop growth, the fertilizer will be released slowly with the degradation of lignin, which greatly prolongs the time of fertilizer effect, especially phosphating modified lignin can effectively prevent phosphorus fertilizer from being permanently absorbed by the soil Fixed, significantly improving the effective utilization of phosphate fertilizer.

Blending phosphated lignin with degradable plastics to extrude blown film can enhance the mechanical properties of the film. The mulch film obtained by this method can still be completely biodegradable, which can not only reduce the consumption of petroleum-based materials and the discharge of pollutants in the biorefinery industry, but also greatly reduce the cost of the mulch film. Due to the darker color of phosphorized lignin, it can reduce the light transmittance of the mulch film, which is beneficial to inhibit the growth of weeds on the ground.

Contents of the invention

The technical problem to be solved by the present invention is to provide a fully degradable mulch film with the effect of slow-release phosphate fertilizer, so as to solve the problem of poor effect existing in the prior art.

The technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned fully degradable mulch film with the effect of slow-release phosphate fertilizer.

In order to solve the problems of the technologies described above, the technical scheme adopted in the present invention is as follows:

A fully degradable mulch film with the effect of slow-release phosphate fertilizer, which includes the following components in parts by mass:

Wherein, the component of preferred following mass parts:

Wherein, the degradable plastics are polybutylene terephthalate/adipate (PBAT), polylactic acid (PLA), polypropylene carbonate (PPC), polysuccinic acid/butylene adipate Any one or combination of glycol esters (PBSA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), preferably polybutylene terephthalate/adipate alcohol esters (PBAT).

Wherein, the phosphating lignin is obtained by phosphating lignin with phosphating reagents such as polyphosphoric acid, phosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphoric anhydride, acid phosphate, phosphorus oxychloride or phosphorus thion chloride, Preference is given to using polyphosphoric acid for phosphating.

Wherein, described phosphating method is:

Add phosphating reagent to lignin, stir for 60-80 hours, and dry to obtain phosphating lignin; wherein, the mass ratio of lignin and phosphating reagent is 1:3-5.

Wherein, the lignin is any one or a combination of alkali lignin, enzymatic lignin, paper lignin, organic solvent lignin, lignosulfonate, and the particle size is 100-1000 mesh.

Wherein, the plasticizer is any one or a combination of several of dibutyl sebacate, triacetin, polyethylene glycol and citric acid ester plasticizers; Plasticizers include tributyl citrate, acetyl tributyl citrate and triethyl citrate.

Wherein, the chain extender is any one of hydroquinone dihydroxyethyl ether, resorcinol dihydroxyethyl ether, bisphenol A, 1,4-butanediol and diisocyanate chain extenders One or a combination of several; wherein, the diisocyanate chain extender includes diphenylmethane diisocyanate and toluene-2,4-diisocyanate.

Wherein, the antioxidant is butyl hydroxyanisole, dibutyl hydroxytoluene, tert-butyl hydroquinone, pentaerythritol bisphosphite, 3-(3,5-di-tert-butyl-4-hydroxybenzene base) any one or a combination of octadecyl propionate and dilauryl thiodipropionate.

Wherein, the heat stabilizer is maleic anhydride and/or epoxidized soybean oil.

Wherein, the lubricant is any one or a combination of pentaerythritol stearate, zinc stearate, calcium stearate and oleic acid amide.

Further, the following components in parts by mass are preferred:

Further, the following components in parts by mass are preferred:

The preparation method of the above-mentioned fully degradable mulch film with slow-release phosphate fertilizer effect, it comprises the steps:

After fully mixing the degradable plastics, phosphorized lignin, plasticizers, chain extenders, antioxidants, heat stabilizers and lubricants in the high-mixer, they are extruded and granulated by a twin-screw granulator. Phosphated lignin-modified plastic composite particles are obtained; the phosphated lignin-modified plastic composite particles are blown into a film to obtain a fully degradable plastic film with the effect of slow-release phosphate fertilizer.

Among them, in the high mixer, the temperature is 100-110°C, the speed is 800-1000rpm, and the mixing time is 10-20min; when extruding and granulating, the temperature is 120-180°C; when blowing into a film, the temperature is 125-1000 150°C.

Beneficial effect:

The invention adopts phosphating lignin-modified biodegradable plastics with the effect of slow-release phosphate fertilizer in the degradation process to prepare fully biodegradable mulch film, which not only effectively utilizes renewable lignin resources, but also reduces the damage caused by biorefining and papermaking industries. Environmental pollution can also reduce the consumption of petroleum-based materials and white pollution in agricultural production. It also helps to improve the utilization rate of phosphorus fertilizers, improve soil, save fertilizer and increase production, so it has good environmental, resource and economic benefits. The use of phosphated lignin is also beneficial to improve the mechanical properties of the fully degradable plastic film and inhibit the growth of weeds. Because lignin is cheap and easy to obtain, it can effectively reduce the production cost of plastic film, which is conducive to market promotion.

Detailed ways

The present invention can be better understood from the following examples. However, those skilled in the art can easily understand that the content described in the embodiments is only for illustrating the present invention, and should not and will not limit the present invention described in the claims.

Example 1

Concrete preparation method comprises the following steps:

(1) Add 90 parts of polyphosphoric acid to 20 parts by weight of alkali lignin, stir for 60 hours, and dry to obtain phosphated lignin;

(2) Add 50 parts of PBAT, 20 parts of PLA, 30 parts of phosphorified lignin described in step (1), 0.6 part of tributyl citrate, 0.8 part of bisphenol A, 0.3 part of tert-butyl Hydroquinone, 0.5 parts of epoxidized soybean oil, and 0.2 parts of zinc stearate were mixed for 15 minutes at a speed of 1000 rpm at 105 ° C to obtain a mixed material;

(3) extruding and granulating the mixed material described in step (2), controlling the temperature at 150-160° C. to obtain phosphated lignin-modified plastic composite particles;

(4) The composite particles described in the step (3) are blown into a film at 140-150° C. to obtain a fully degradable plastic film with the effect of slow-release phosphate fertilizer.

Example 2

Concrete preparation method comprises the following steps:

(1) Add 140 parts of polyphosphoric acid to 40 parts by weight of enzymatic lignin, stir for 80 hours, and dry to obtain phosphorified lignin;

(2) Add 55 parts of PBAT, 25 parts of PBSA, 20 parts of phosphorified lignin described in step (1), 0.6 part of triacetin, 0.3 part of 1,4-butanediol, 0.4 part of Dibutyl hydroxytoluene, 0.6 parts of maleic anhydride and 0.15 parts of calcium stearate were mixed for 15 minutes at 105° C. at a speed of 1000 rpm to obtain a mixed material;

(3) extruding and granulating the mixed material described in step (2), controlling the temperature at 140-150° C. to obtain phosphated lignin-modified plastic composite particles;

(4) The composite particles described in the step (3) are blown into a film at 130-140° C. to obtain a fully degradable plastic film with the effect of slow-release phosphate fertilizer.

Comparative example 1

The phosphorified lignin in Example 1 was replaced with PBAT of the same quality, and the mulch film prepared by referring to the steps of Example 1 was used as Comparative Example 1.

Performance Testing

A universal tensile machine was used to measure the tensile strength of the materials of the above-mentioned Examples 1, 2 and Comparative Example 1, and a biocomposting degradation experiment was carried out on the above-mentioned materials. The specific test results are shown in Table 1.

Table 1

Tensile strength (MPa) 6-month compost degradation rate (%) Example 1 33 >99% Example 2 30 >99% Comparative example 1 20 >99%

It can be seen from the test results shown in Table 1 that the tensile strength of the phosphated lignin-modified mulch film has been significantly enhanced and meets the requirement of complete degradation.

The mulch film in embodiment 1,2 and comparative example 1 is carried out pot experiment, the phosphorus element content in soil is periodically measured (in comparative example 1 group, apply phosphorus fertilizer before experiment starts, its phosphorus element content and embodiment 1 The content of phosphorus element in the plastic film is the same), and the slow release of phosphorus fertilizer is shown in Table 2.

Table 2

time/day 0 30 60 90 Example 1 (mg/kg) 0 15.8 36.0 55.9 Example 2 (mg/kg) 0 13.1 32.2 48.8 Comparative example 1 (mg/kg) 0 12.5 14.0 14.2

The results in Table 2 show that the mulch film of the present invention has the effect of slow-release phosphate fertilizer, and the release of phosphate fertilizer to the soil can last for 90 days, and the fertilizer effect time is long.

The specific embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiments, so changes and modifications made without departing from the spirit and purpose of the present invention should be covered within the scope of the present invention .

Claims (11)

1. a kind of degradable mulch with slow-release phosphate fertilizer, which is characterized in that it includes the component of following mass fraction：

2. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that described is degradable Plastics are poly terephthalic acid/tetramethylene adipate, polylactic acid, poly (propylene carbonate), poly-succinic/adipic acid butanediol Any one or the combination of several of them in ester, polyhydroxyalkanoates and poly butylene succinate.

3. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that the phosphatization wood Quality is lignin through polyphosphoric acid, phosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphoric anhydride, acid phosphate, phosphorus oxychloride or phosphorus thiochloride It is obtained after phosphatization.

4. the degradable mulch with slow-release phosphate fertilizer according to claim 3, which is characterized in that the lignin For in alkali lignin, enzymolysis xylogen, papermaking lignin, organic solvent lignin, lignosulfonates any one or it is several The combination of kind, grain size are 100~1000 mesh.

5. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that the plasticizer For any one or a few the group in dibutyl sebacate, glyceryl triacetate, polyethylene glycol and citric acid ester plasticizer It closes.

6. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that the chain extender For hydroquinone two hydroxy ethyl ether, resorcinol dihydroxyethyl ether, bisphenol-A, 1,4- butanediols and diisocyanates chain extender In any one or the combination of several of them.

7. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that described is anti-oxidant Agent is butylated hydroxy anisole, dibutyl hydroxy toluene, tert-butyl hydroquinone, pentaerythritol bis-phosphite, 3- (3,5- bis- Tert-butyl-hydroxy phenyl) any one or the combination of several of them of the propionic acid ten in the double lauryls of caprylate and thio-2 acid.

8. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that the thermostabilization Agent is maleic anhydride and/or epoxidized soybean oil.

9. the degradable mulch with slow-release phosphate fertilizer according to claim 1, which is characterized in that the lubricant For any one or the combination of several of them in pentaerythritol stearate, zinc stearate, calcium stearate and oleamide.

10. the preparation method of the degradable mulch with slow-release phosphate fertilizer described in claim 1, which is characterized in that it is wrapped Include following steps：

The degradation plastic of formula ratio, phosphatization lignin, plasticizer, chain extender, antioxidant, heat stabilizer and lubricant are existed After being sufficiently mixed in high mixer, through dual-screw pelletizer extruding pelletization, the plastics compound particle of phosphatization lignin modification is obtained；Phosphorus The plastics compound particle for changing lignin modification has effects that the degradable mulch of slow-release phosphate fertilizer through Blown Film.

11. preparation method according to claim 10, which is characterized in that in high mixer, temperature is 100~110 DEG C, rotating speed For 800~1000rpm, incorporation time is 10~20min；When extruding pelletization, temperature is 120~180 DEG C；When Blown Film, temperature Degree is 125~150 DEG C.