CN114426720B

CN114426720B - Bio-based plastic, bio-based plastic film, raw material composition, preparation and application

Info

Publication number: CN114426720B
Application number: CN202011186212.5A
Authority: CN
Inventors: 施晓旦; 刘晓辉; 金霞朝
Original assignee: Shanghai Changfa New Materials Co Ltd
Current assignee: Shanghai Changfa New Materials Co Ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2023-05-30
Anticipated expiration: 2040-10-29
Also published as: CN114426720A

Abstract

The invention discloses a bio-based plastic, a bio-based plastic film, a raw material composition, preparation and application. The raw material composition of the bio-based plastic comprises the following components in parts by weight: 40-90 parts of polyethylene resin, 5-30 parts of dry powder of papermaking waste, 5-30 parts of starch and 1-15 parts of auxiliary agent; wherein the polyethylene resin is metallocene polyethylene resin or high-density polyethylene resin; the auxiliary agent is one or more of a compatilizer, a cross-linking agent, a plasticizer and a dispersion lubricant. The preparation process of the bio-based plastic and the bio-based plastic film is simple, and the bio-based plastic film have good impact resistance, tensile property and elongation. Meanwhile, the addition of the bio-based filler, namely papermaking waste, not only greatly reduces the raw material cost of the bio-based plastic film, but also ensures that the bio-based plastic film has the degradable performance, thereby realizing the maximum utilization of resources by changing waste into valuables.

Description

Bio-based plastic, bio-based plastic film, raw material composition, preparation and application

Technical Field

The invention relates to a bio-based plastic, a bio-based plastic film, a raw material composition, preparation and application.

Background

The plastic film plays an irreplaceable role in the fields of packaging and agricultural coverage, and along with the improvement of the economic level, energy conservation and environmental protection become the main stream of the current society, and in recent years, the research on the degradable film is more and more intensive and the application is more and more extensive. Most of films on the market at present are made of petroleum-based polyolefin (polyethylene, polypropylene, polyvinyl chloride and the like) as raw materials, and most of the products have long degradation period and cannot be recycled, so that a large amount of residual garbage can be generated, and quite serious white pollution is caused.

In nature, lignin reserves are only inferior to cellulose, and it is counted that the pulping and paper industry separates about 1.4 million tons of cellulose from plants each year, and a large amount of lignin, a byproduct of paper waste, is obtained. However, up to now, more than 95% of papermaking waste is still directly discharged into a river or is burnt after concentration, so that the waste of resources and the pollution to the environment are caused, and if the waste can be effectively utilized, the waste is of profound significance to the development of social economy and environmental protection.

Therefore, there is a need in the art to develop a plastic film which has the advantages of rapid degradation speed, little environmental pollution, wide raw material sources, easy obtainment and maximum utilization of resources.

Disclosure of Invention

The invention aims to overcome the defects of low degradation speed of a plastic film in nature, large influence on environment, low availability of papermaking waste generated in the papermaking industry and the like in the prior art and provides a bio-based plastic, a bio-based plastic film, a raw material composition, preparation and application. The invention adds papermaking waste and starch into specific polyethylene resin to prepare the bio-based plastic and the bio-based plastic film, the preparation process of the bio-based plastic and the bio-based plastic film is simple, and the bio-based plastic film have good shock resistance, tensile property and elongation, the tensile strength can reach more than 20.9MPa, and the elongation at break can reach more than 428.9%; the prepared product also has ideal stability and opening performance; meanwhile, the addition of the bio-based filler, namely papermaking waste, not only greatly reduces the raw material cost of the bio-based plastic film, but also ensures that the bio-based plastic film has the degradable performance, thereby realizing the maximum utilization of resources by changing waste into valuables.

The invention adopts the following technical scheme to solve the technical problems:

the invention provides a raw material composition of bio-based plastics, which comprises the following components in parts by weight: 40-90 parts of polyethylene resin, 5-30 parts of dry powder of papermaking waste, 5-30 parts of starch and 1-15 parts of auxiliary agent; wherein the polyethylene resin is a metallocene polyethylene resin (MLLDPE) or a high density polyethylene resin (HDPE); the auxiliary agent is one or more of a compatilizer, a cross-linking agent, a plasticizer and a dispersion lubricant.

In the present invention, the polyethylene resin may be a polyethylene resin manufactured by Presman Polymer Co., ltd.

In the invention, the dry powder of the papermaking waste can be obtained by cleaning, drying, crushing and sieving the papermaking waste conventionally generated in the papermaking process in the field.

Wherein, the papermaking waste can be one or more of putrescence pulp, pulp slag, wood veneer, pulping waste liquid extract and siliceous white mud, and is preferably putrescence pulp or pulping waste liquid extract.

Wherein, the pulping waste liquid extract can be prepared by referring to the invention patent CN102587179B, and specifically comprises the following components: (a) selecting eucalyptus pieces and performing pre-steaming; (b) According to the mass ratio of eucalyptus pieces to water of 1 (3-10), pumping the aqueous solution of eucalyptus pieces to the top of an independent continuous hydrolysis tower by a pump, carrying out hydrolysis reaction on the eucalyptus pieces for 1-4 hours at the reaction temperature of 120-180 ℃, and extracting hydrolysis liquid from the lower part of the hydrolysis tower after the pre-hydrolysis reaction; (c) And (3) steaming the hydrolyzed eucalyptus pieces by a sulfate method, wherein the steaming conditions are as follows: the hydrolyzed eucalyptus pieces are added at a constant speed at the top of a digester, the vulcanizing degree of the effective alkali is 20-40% based on 16-24% of the absolute dry quantity of the eucalyptus pieces calculated by NaOH, the boiling temperature is 140-170 ℃, the mass ratio of the eucalyptus pieces to water is 1 (3-6), the boiling time is 1-4 h, and after dissolving pulp is collected, the residual substances in a hydrolysis tower are filtered, so that the pulping waste liquid extract is obtained.

Preferably, the preparation method of the pulping waste liquid extract comprises the steps of a, selecting eucalyptus pieces and performing pre-steaming; b, the mass ratio of eucalyptus pieces to water is 1:5, enabling the aqueous solution of eucalyptus chips to reach the top of an independent continuous hydrolysis tower by using a pump, enabling the hydrolysis reaction time of the eucalyptus chips to be 2 hours, enabling the reaction temperature to be 165 ℃, and extracting hydrolysis liquid from the lower part of the hydrolysis tower after the pre-hydrolysis reaction; and c, steaming the hydrolyzed eucalyptus pieces by a sulfate method under the following conditions, wherein the hydrolyzed eucalyptus pieces are uniformly added at the top of a steaming pot, the effective alkali based on the absolute dry quantity of the eucalyptus pieces is 18 percent calculated by NaOH, the vulcanizing degree of the effective alkali is 28 percent, the steaming temperature is 150 ℃, the mass ratio of the eucalyptus pieces to water is 1:5, the steaming time is 2 hours, and after dissolving pulp is collected, the residual substances in a hydrolysis tower are filtered, so that the pulping waste liquid extract is obtained.

The humic acid pulp can be a material formed by accumulating sediment, bacteria and mold after growing and propagating in the sediment when the pulp flows through various pipelines and equipment of a net part system of a paper machine in the papermaking process of the papermaking field.

Wherein, the pulp slag is the residual material after the pulp is filtered, screened and purified in the papermaking process in the papermaking field.

In the present invention, the particle size of the dry powder of papermaking waste may be conventional in the art, preferably 200 to 5000 mesh, more preferably 300 to 3000 mesh, still more preferably 500 to 2000 mesh.

In the present invention, the starch may be a starch conventionally used in the art, and may be generally an edible grade starch, preferably one or more of corn starch, tapioca starch, potato starch and wheat starch, more preferably corn starch or tapioca starch.

In the present invention, the auxiliary agent is preferably:

a mixture of a cross-linking agent, a plasticizer and a dispersing lubricant;

or alternatively, the first and second heat exchangers may be,

a plasticizer, a dispersing lubricant and a compatibilizer.

In the present invention, the compatibilizing agent may be a compatibilizing agent conventionally used in the art, preferably maleic anhydride grafted PE.

In the present invention, the crosslinking agent may be a crosslinking agent conventionally used in the art, preferably one or more of DCP (dicumyl peroxide), BPO (benzoyl peroxide) and tetrabutyl titanate, more preferably BPO.

In the present invention, the plasticizer may be a plasticizer conventionally used in the art, preferably one or more of TBC (tributyl citrate), ATBC (acetyl tri-n-butyl citrate), glycerin and epoxidized soybean oil, more preferably glycerin or TBC.

In the present invention, the dispersion lubricant may be a dispersion lubricant conventionally used in the art, preferably one or more of stearic acid, butyl stearate, oleamide, ethylenebisstearamide and PE wax, more preferably stearic acid or PE wax.

In the present invention, the polyethylene resin is preferably 50 to 80 parts by weight, more preferably 70 to 80 parts by weight.

In the invention, the dry powder of the papermaking waste is preferably 10-30 parts by weight, more preferably 15-30 parts by weight.

In the present invention, the starch is preferably 10 to 25 parts by weight, more preferably 10 to 15 parts by weight.

In the present invention, the weight part of the auxiliary agent is preferably 7 to 13 parts, more preferably 8 to 13 parts.

In the present invention, the weight part of the compatibilizing agent may be a conventional weight part of the same in the art, preferably 1 to 8 parts, more preferably 1 to 5 parts.

In the present invention, the weight part of the crosslinking agent may be a conventional weight part of the same in the art, preferably 0.5 to 3 parts, more preferably 1 to 2.5 parts.

In the present invention, the plasticizer may be used in an amount of about 4 to about 8 parts, preferably about 5 to about 7 parts, more preferably about 6 to about 7 parts, based on the weight of the plasticizer as conventional in the art.

In the present invention, the weight part of the dispersion lubricant may be a conventional weight part of the same in the art, preferably 0.5 to 3 parts, more preferably 1 to 2.5 parts.

The invention also provides a preparation method of the bio-based plastic, which specifically comprises the following steps: the raw material composition of the bio-based plastic is mixed, extruded and plasticized.

Wherein the mixing conditions and methods may be those conventional in the art for such operations, typically performed in a high speed blender.

When the mixing is carried out in a high speed blender, the speed of rotation of the high speed blender may be a speed conventional in the art for such operations, preferably 10 to 5000rpm, more preferably 100 to 3000rpm, still more preferably 200 to 400rpm, for example 300rpm.

The mixing time may be a time conventional in this type of operation in the art, preferably 10 to 2000 minutes, more preferably 20 to 1000 minutes, still more preferably 30 to 60 minutes.

The temperature of the mixing may be conventional in the art for such operations, preferably 20 to 150 ℃, more preferably 30 to 120 ℃, still more preferably 50 to 100 ℃.

The conditions and methods of extrusion plasticization may be those conventional in the art for such operations, typically performed in a twin screw extruder.

In the extrusion plasticizing in a twin screw extruder, the temperature of the twin screw extruder from zone one to zone six may be a temperature conventional in such operations in the art, preferably 60 to 220 ℃, more preferably 80 to 200 ℃, still more preferably 90 to 190 ℃.

In a preferred embodiment, the twin screw extruder has a temperature of 120 to 150 ℃, 140 to 155 ℃, 140 to 170 ℃, 170 to 180 ℃ or 170 to 195 ℃ from zone one to zone six, respectively.

In another preferred embodiment, the temperature of the parallel twin screw extruder from zone one to zone six is 130 to 150 ℃, 145 to 155 ℃, 150 to 170 ℃, 175 to 180 ℃ or 175 to 180 ℃, respectively.

In the extrusion plasticizing in a twin screw extruder, the temperature of the head of the twin screw extruder may be a temperature conventional in the art for such operation, preferably 60 to 220 ℃, more preferably 80 to 200 ℃, still more preferably 170 to 175 ℃.

In the extrusion plasticizing in a twin-screw extruder, the rotational speed of the twin-screw extruder may be a rotational speed conventional in this type of operation in the art, preferably 30 to 600rpm, more preferably 60 to 450rpm, still more preferably 120 to 200rpm, for example 150rpm.

In the preparation method of the bio-based plastic, the extrusion plasticizing process can further comprise a granulating operation.

The invention also provides a bio-based plastic prepared by the preparation method of the bio-based plastic.

The invention also provides a bio-based plastic film which is prepared by blowing and molding the bio-based plastic.

The conditions and methods of blown film formation may be those conventional in the art for such operations.

The temperature of the blown film formation may be conventional in the art, preferably from 90 to 220 c, more preferably from 178 to 185 c, for example 180 c.

The invention also provides an application of the bio-based plastic in the bio-based plastic film as a preparation raw material.

On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.

The reagents and materials used in the present invention are commercially available.

The invention has the positive progress effects that: the preparation process of the bio-based plastic and the bio-based plastic film is simple, and the prepared bio-based plastic and bio-based plastic film has good shock resistance, tensile property and elongation, the tensile strength can reach more than 20.9MPa, and the elongation at break can reach more than 428.9%; the prepared product also has ideal stability and opening performance; the paper making waste and the starch are added into specific polyethylene resin, the traditional polyethylene material is modified into the bio-based plastic and the bio-based plastic film, and the paper making waste and the starch have good mechanical property and impact resistance and also have easy degradation property, so that the degradation time of the traditional polyethylene material is shortened, the paper making waste and the starch play a good role in relieving white pollution and protecting soil, the cost is reduced, the popularization is better, the greater utilization of resources is realized, and the environment is better protected.

Detailed Description

The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

The specific preparation method of the pulping waste liquid extract in the following examples and comparative examples comprises the following steps: a, selecting eucalyptus pieces and performing pre-steaming; b, the mass ratio of eucalyptus pieces to water is 1:5, enabling the aqueous solution of eucalyptus chips to reach the top of an independent continuous hydrolysis tower by using a pump, enabling the hydrolysis reaction time of the eucalyptus chips to be 2 hours, enabling the reaction temperature to be 165 ℃, and extracting hydrolysis liquid from the lower part of the hydrolysis tower after the pre-hydrolysis reaction; and c, steaming the hydrolyzed eucalyptus pieces by a sulfate method under the following conditions, wherein the hydrolyzed eucalyptus pieces are uniformly added at the top of a steaming pot, the effective alkali based on the absolute dry quantity of the eucalyptus pieces is 18 percent calculated by NaOH, the vulcanizing degree of the effective alkali is 28 percent, the steaming temperature is 150 ℃, the mass ratio of the eucalyptus pieces to water is 1:5, the steaming time is 2 hours, after dissolving pulp is collected, the residue in a hydrolysis tower is filtered and concentrated to obtain a pulping waste liquid extract, and the pH value of the pulping waste liquid is 11.

In the following examples, the pulp is a sediment formed by the pulp flowing through various pipelines and equipment of the wire section system of the paper machine, and the bacteria and mold are materials formed after growing and propagating in the sediment.

In the following examples and comparative examples, the pulp residue was obtained by filtering, sieving, and purifying pulp during the papermaking process, and the remaining material after the good pulp was separated.

Polyethylene resins used in the following examples and comparative examples were all purchased from the japanese priman polymers inc.

Example 1

1. Preparation of biobased plastics

The kinds and amounts of the components in the raw material composition of the bio-based plastic are shown in Table 1. In the embodiment, the dry powder of the papermaking waste in the raw material composition is the dry powder of the beancurd slurry prepared by cleaning, drying, crushing and sieving beancurd slurry, and the particle size of the dry powder of the papermaking waste is 500-2000 meshes.

Adding the raw material composition of the bio-based plastic into a high-speed blender for mixing, wherein the mixing temperature is 100 ℃, the mixing rotating speed is 400rpm, and the mixing time is 60 minutes, so as to obtain a primary mixture;

extruding, plasticizing and granulating the initial mixture in a double-screw extruder, wherein the temperatures from one area to six areas of the double-screw extruder are 120 ℃, 145 ℃, 170 ℃, 175 ℃ and 175 ℃ respectively; the temperature of the head of the double-screw extruder is 175 ℃, and the rotating speed of the screw is 200rpm, so that master batches are prepared;

2. preparation of bio-based plastic film

And (3) putting the master batch into a film blowing machine for film blowing molding, and blowing film molding at 180 ℃ to obtain the bio-based plastic film.

TABLE 1

Example 2

1. Preparation of biobased plastics

The types and amounts of the components in the raw material composition of the bio-based plastic are shown in Table 2. In the embodiment, the papermaking waste in the raw material composition is pulping waste extract dry powder obtained by cleaning, drying, crushing and sieving the pulping waste extract, and the particle size of the papermaking waste dry powder is 200-2000 meshes.

Adding the raw material composition of the bio-based plastic into a high-speed blender for mixing, wherein the mixing temperature is 50 ℃, the mixing rotating speed is 300rpm, and the mixing time is 30min, so as to obtain a primary mixture;

extruding, plasticizing and granulating the initial mixture in a double-screw extruder, wherein the temperatures from one area to six areas of the double-screw extruder are 150 ℃, 155 ℃, 170 ℃, 175 ℃ and 175 ℃ respectively; the temperature of the head of the double-screw extruder is 170 ℃, and the rotating speed of the screw is 120rpm, so that master batches are prepared;

2. preparation of bio-based plastic film

And (3) putting the master batch into a film blowing machine for film blowing molding, and blowing film molding at 178 ℃ to obtain the bio-based plastic film.

TABLE 2

Composition of the components	Dosage (portion)
		HDPE	70
Corn starch	15
		Pulping waste liquid extract dry powder	15
Compatibilizers (maleic anhydride grafted PE)	1
		Plasticizer (glycerol)	6
Dispersing lubricant (PE wax)	1

Example 3

1. Preparation of biobased plastics

The kinds and amounts of the respective components in the raw material composition of the bio-based plastic are shown in Table 3. In the embodiment, the papermaking waste in the raw material composition is pulping waste extract dry powder obtained by cleaning, drying, crushing and sieving the pulping waste extract, and the particle size of the papermaking waste dry powder is 300-1000 meshes.

Adding the raw material composition of the bio-based plastic into a high-speed blender for mixing, wherein the mixing temperature is 50 ℃, the mixing rotating speed is 200rpm, and the mixing time is 30min, so as to obtain a primary mixture;

extruding, plasticizing and granulating the initial mixture in a double-screw extruder, wherein the temperatures from one area to six areas of the double-screw extruder are 130 ℃, 140 ℃, 150 ℃, 180 ℃ and 180 ℃ respectively; the temperature of the head of the double-screw extruder is 170 ℃, the rotating speed of the screw is 150rpm, and master batches are prepared;

2. preparation of bio-based plastic film

And (3) putting the master batch into a film blowing machine for film blowing molding, and performing film blowing molding at 185 ℃ to obtain the bio-based plastic film.

TABLE 3 Table 3

Composition of the components	Dosage (portion)
		MLLDPE	70
Pulping waste liquid extract dry powder	30
		Compatibilizers (maleic anhydride grafted PE)	5
Cassava starch	10
		Plasticizer (TBC)	7
Dispersing lubricant (stearic acid)	1

Comparative example 1

1. Preparation of plastics

The kinds and amounts of the respective components in the raw material composition of the plastic are shown in Table 4.

Adding the raw material composition of the plastic into a high-speed blender for mixing, wherein the mixing temperature is 60 ℃, the mixing rotating speed is 200rpm, and the mixing time is 60min, so as to obtain a primary mixture;

extruding, plasticizing and granulating the initial mixture in a double-screw extruder, wherein the temperatures from one area to six areas of the double-screw extruder are 170 ℃, 180 ℃, 185 ℃, 190 ℃ and 190 ℃ respectively; the temperature of the head of the double-screw extruder is 185 ℃, the rotating speed of the screw is 200rpm, and master batches are prepared;

2. preparation of plastic film

And (3) putting the master batch into a film blowing machine for film blowing molding, and blowing film molding at 190 ℃ to obtain the plastic film.

TABLE 4 Table 4

Composition of the components	Dosage (portion)
		HDPE	80
Starch	20
		Cross-linking agent (tetrabutyl titanate)	3
Plasticizer (sorbitol)	5
		Dispersing lubricant (PE wax)	2

Comparative example 2

1. Preparation of biobased plastics

The kinds and amounts of the respective components in the raw material composition of the bio-based plastic are shown in Table 5. In the embodiment, the papermaking waste in the raw material composition is wood Pi Ganfen prepared by cleaning, drying, crushing and sieving wood skin, and the particle size of the papermaking waste dry powder is 300-1000 meshes.

Adding the raw material composition of the bio-based plastic into a high-speed blender for mixing, wherein the mixing temperature is 80 ℃, the mixing rotating speed is 200rpm, and the mixing time is 40min, so as to obtain a primary mixture;

extruding, plasticizing and granulating the initial mixture in a double-screw extruder, wherein the temperatures from one area to six areas of the double-screw extruder are 140 ℃, 145 ℃, 155 ℃, 165 ℃ and 165 ℃ respectively; the temperature of the head of the double-screw extruder is 155 ℃, the rotating speed of the screw is 200rpm, and master batches are prepared;

2. preparation of bio-based plastic film

And (3) putting the master batch into a film blowing machine for film blowing forming, wherein the film blowing forming temperature is 170 ℃, and the bio-based plastic film is prepared.

TABLE 5

Effect examples

The master batches before film blowing of examples 1 to 3 and comparative examples 1 to 2 were made into test bars with a dumbbell shape, a length of 150mm, a width of a narrow portion of 10mm and a gauge length of 75mm according to the method in national standard GB/T1040.2-2006, and the tensile strength and elongation at break of the test bars were measured according to national standard GB/T1040.1-2006 by using a universal electronic tensile tester (KY 8000C type), and specific data are shown in Table 6.

TABLE 6

Numbering device	Tensile Strength/MPa	Elongation at break/%
			Example 1	23.2	428.9
Example 2	20.9	467.2
			Example 3	22.5	437.8
Comparative example 1	24.3	386.7
			Comparative example 2	21.6	398.4

The results show that the mechanical properties of the bio-based plastics prepared in the embodiments 1-3 of the invention are better than those of the materials prepared in the comparative examples 1-2, the use requirements can be met, the cost is greatly reduced, waste is changed into valuable, and the resources are most effectively utilized.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The raw material composition of the bio-based plastic is characterized by comprising the following components in parts by weight: 40-70 parts of polyethylene resin, 15-30 parts of papermaking waste dry powder, 5-30 parts of starch and 1-15 parts of auxiliary agent; wherein the polyethylene resin is metallocene polyethylene resin or high-density polyethylene resin; the dry powder of the papermaking waste is obtained by cleaning, drying, crushing and sieving a pulping waste liquid extract; the auxiliary agent is a mixture of a plasticizer, a dispersion lubricant and a compatilizer; the plasticizer is glycerol or TBC; the dispersing lubricant is stearic acid or PE wax; the compatilizer is maleic anhydride grafted PE.

2. The raw material composition of bio-based plastic according to claim 1, wherein the weight part of the polyethylene resin is 50-70;

and/or 10-25 parts by weight of starch;

and/or 7-13 parts by weight of an auxiliary agent;

and/or 1-8 parts by weight of the compatilizer;

and/or 4-8 parts by weight of plasticizer;

and/or the weight part of the dispersion lubricant is 0.5-3 parts.

3. The raw material composition of bio-based plastics according to claim 2, wherein the starch is 10 to 15 parts by weight;

and/or 8-13 parts by weight of an auxiliary agent;

and/or 1-5 parts by weight of the compatilizer;

and/or 5-7 parts by weight of plasticizer;

and/or the weight part of the dispersion lubricant is 1-2.5 parts.

4. The raw material composition of bio-based plastic according to claim 3, wherein the plasticizer is 6 to 7 parts by weight.

5. The raw material composition of bio-based plastic according to any one of claims 1 to 4, wherein the dry powder of papermaking waste has a particle size of 200 to 5000 mesh;

and/or the starch is one or more of corn starch, tapioca starch, potato starch and wheat starch.

6. A raw material composition for bio-based plastics according to claim 5,

the particle size of the papermaking waste dry powder is 300-3000 meshes;

and/or, the starch is corn starch or tapioca starch.

7. A raw material composition for bio-based plastics according to claim 6,

the particle size of the papermaking waste dry powder is 500-2000 meshes.

8. A method for preparing bio-based plastic, comprising the steps of: the raw material composition of the bio-based plastic according to any one of claims 1 to 7, which is obtained by mixing, extrusion plasticizing.

9. The method for preparing a bio-based plastic according to claim 8, wherein the rotational speed of the mixing is 10 to 5000rpm;

and/or mixing for 10-2000 min;

and/or, the temperature of the mixing is 20-150 ℃;

and/or, the extrusion plasticizing is performed in a twin screw extruder;

and/or the extrusion plasticizing further comprises granulating operation.

10. The method for preparing a bio-based plastic according to claim 9, wherein the rotational speed of the mixing is 100 to 3000rpm;

and/or mixing for 20-1000 min;

and/or, the temperature of the mixing is 30-120 ℃;

and/or the temperature of the twin-screw extruder from the first area to the sixth area is 60-220 ℃; and/or the temperature of the head of the double-screw extruder is 60-220 ℃; and/or the rotating speed of the double-screw extruder is 30-600 rpm.

11. The method for preparing a bio-based plastic according to claim 10, wherein the rotational speed of the mixing is 200 to 400rpm;

and/or mixing for 30-60 min;

and/or the mixing temperature is 50-100 ℃;

and/or the temperature of the twin-screw extruder from the first area to the sixth area is 80-200 ℃; and/or the temperature of the head of the double-screw extruder is 80-200 ℃; and/or the rotating speed of the double-screw extruder is 60-450 rpm.

12. The method for preparing a bio-based plastic according to claim 11, wherein the rotational speed of the mixing is 300rpm;

and/or the temperature of the twin-screw extruder from one zone to six zones is 90-190 ℃; and/or the temperature of the head of the double-screw extruder is 170-175 ℃; and/or the rotating speed of the double-screw extruder is 120-200 rpm.

13. The method of preparing a bio-based plastic according to claim 12, wherein the twin screw extruder has a rotational speed of 150rpm.

14. A bio-based plastic, characterized in that it is produced by the method for producing a bio-based plastic according to any one of claims 8 to 13.

15. Use of the bio-based plastic according to claim 14 as a preparation raw material in a bio-based plastic film.

16. A bio-based plastic film, characterized in that it is produced from the bio-based plastic according to claim 14 by blow molding.

17. The biobased plastic film of claim 16, wherein the blown film is formed at a temperature of 90-220 ℃.

18. The biobased plastic film of claim 17, wherein the blown film is formed at a temperature of 178-185 ℃.

19. The biobased plastic film of claim 18, wherein said blown film is formed at a temperature of 180 ℃.