Environment-friendly degradable plastic-wood material and preparation method thereof

Abstract

The application relates to the technical field of plastic-wood materials, and discloses an environment-friendly degradable plastic-wood material and a preparation method thereof. The plastic-wood material comprises the following raw materials: PBAT resin, bamboo powder, a coupling agent, a flame-retardant synergist, a toughening modification component, a filling material, a stabilizer, a lubricant and an antioxidant. The flame-retardant synergist is grafted with a nitrogen-phosphorus flame retardant on the surface of palygorskite through a chemical connection mode, the organic-inorganic synergistic flame-retardant effect is utilized, the prepared plastic-wood material has good flame-retardant performance, the structure of the toughening modification component contains a flexible silicon-oxygen chain and a castor oil molecule, the toughness of the plastic-wood material can be effectively improved, the problems of breakage and deformation of the material under external force impact or stress can be avoided, and the silicon element in the structure can further improve the flame-retardant performance of the plastic-wood material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plastic-wood materials, in particular to an environment-friendly degradable plastic-wood material and a preparation method thereof. BACKGROUND

[0002] Plastic-wood material is a kind of material which is compounded by wood powder or other plant fibers and thermoplastic plastics through a specific processing technology, and has the dual characteristics of wood and plastic, and is widely used in the fields of floor, fence, outdoor bench, packaging material, automotive interior parts, etc. Among them, the thermoplastic plastic usually selects polyolefin plastic, but the polyolefin plastic is difficult to biodegrade, and the degradation period is very long, which can be up to about 200 years in ordinary environment. Therefore, the development of degradable plastic-wood material can solve the environmental pollution problem caused by the difficulty of polyolefin plastic to degrade, and has important social value and broad application prospect.

[0003] PBAT resin is a kind of thermoplastic polymer material, which can be completely decomposed by microorganisms in natural state, and meets the development concept of contemporary ecological green environmental protection. If it is used as the matrix of plastic-wood material, it can give the plastic-wood material good biodegradability. With the widening of application field, the performance requirements of plastic-wood material are getting higher and higher, and the development of multifunctional plastic-wood material has become the focus of researchers. Since wood powder and PBAT resin are flammable materials, they are easy to burn, and have the phenomenon of melting and dripping during combustion, which can easily cause fire and bring great loss to people. In addition, plastic-wood material needs to have excellent toughness to avoid brittle fracture, deformation or creep and other problems of the material when it is subjected to external impact or stress, so as to ensure the integrity of the material under stress and prolong its service life.

[0004] In the prior art, in order to improve the performance of plastic-wood material, functional additives are often used to fill and modify the matrix of the material. For example, the patent for invention with publication number CN101570639B discloses a flame-retardant wood-plastic composite material and a preparation method thereof. The material is made of modified waste plastic, wood fiber, intumescent flame retardant, lubricant and additive. By adding intumescent flame retardant in the matrix, the prepared wood-plastic composite material has good flame-retardant performance. Therefore, high-performance plastic-wood material can be prepared by adding optimized components in the preparation process of plastic-wood material. SUMMARY

[0005] In order to solve the problems mentioned in the background art, the purpose of the present application is to provide an environment-friendly degradable plastic-wood material and a preparation method thereof.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The environment-friendly degradable plastic-wood material comprises the following raw materials in parts by weight: PBAT resin 45-65 parts, bamboo powder 30-40 parts, coupling agent 1-2 parts, flame-retardant synergist 6-9 parts, toughening modification component 5-8 parts, filling material 5-10 parts, stabilizer 1-3 parts, lubricant 2-4 parts, and antioxidant 0.5-1.5 parts.

[0008] Further, the preparation method of the flame-retardant synergist comprises the following steps:

[0009] D1: adding palygorskite and dimethyl sulfoxide solution into a reactor, ultrasonic dispersion to form a uniform dispersion liquid, then adding pyridine-3,4-dicarboxylic anhydride and p-toluenesulfonic acid into the dispersion liquid, after completion of the addition, increasing the temperature to 95-105 DEG C, stirring for 3-7 h under the temperature condition, then filtering to separate the solid material, and after washing and drying, the modified palygorskite is obtained;

[0010] D2: mixing the modified palygorskite with N,N-dimethylformamide, ultrasonic dispersion for 15-25 min, under the condition of continuous nitrogen, adding pentaerythritol phosphate and catalyst, increasing the temperature of the system to 90-110 DEG C under stirring, and keeping the temperature for 3-5 h, then pouring out the material, after natural cooling, filtering to separate the solid material, and the flame-retardant synergist is obtained.

[0011] Further, in step D1, the average particle size of the palygorskite is 4 μm.

[0012] Further, in step D1, the mass ratio of the palygorskite to pyridine-3,4-dicarboxylic anhydride is 1:0.1-0.3.

[0013] Further, in step D2, the catalyst is any one of p-toluenesulfonic acid, sulfamic acid or trifluoromethanesulfonic acid.

[0014] It can be inferred that the principle of the above scheme is that in step D1, the palygorskite surface contains hydroxyl groups, which can react with the anhydride groups in the structure of pyridine-3,4-dicarboxylic anhydride under the action of p-toluenesulfonic acid to obtain modified palygorskite; in step D2, the carboxyl groups produced on the surface of the modified palygorskite due to ring-opening reaction can react with the hydroxyl groups in the structure of pentaerythritol phosphate under the action of catalyst, so as to realize the surface modification of palygorskite and prepare the flame-retardant synergist.

[0015] Further, the preparation method of the toughening modification component comprises the following steps:

[0016] Under the protection of nitrogen, castor oil and methylphenyldichlorosilane are added into toluene, mechanically stirred to be uniform, then a promoter is added, after completion of the addition, heating is started, after the temperature of the system reaches 65-75 DEG C, constant temperature stirring is carried out for 4-6 h, and the solvent is removed by rotary evaporation to obtain the toughening modification component.

[0017] Further, the promoter is any one of triethylamine or pyridine.

[0018] It can be inferred that the principle of the above scheme is that, due to the high activity of Si-Cl in the structure of methylphenyldichlorosilane, under the action of the promoter, a continuous substitution reaction with the hydroxyl groups in the structure of castor oil can occur, and by controlling the amount of reactants, a polymer with a network structure, i.e., a toughening modification component, can be formed by continuous polymerization between each other.

[0019] A preparation method of an environmentally friendly degradable plastic-wood material, comprising the following steps:

[0020] (1) PBAT resin, bamboo powder and coupling agent are put into a high-speed mixer, mixed uniformly, and then flame-retardant synergist, toughening modification component, filler, stabilizer, lubricant and antioxidant are added, and stirred and mixed at a stirring speed of 400-600 r / min for 1-2 h to obtain a mixture;

[0021] (2) the mixture is transferred to a double-screw extruder for extrusion and granulation, and finally the extruded granules are placed in a mold, and hot pressing and then cold pressing can obtain the plastic-wood material.

[0022] Further, in step (1), the filler is any one of talcum powder, mica powder or titanium white powder.

[0023] Further, in step (2), in the double-screw extruder, the head temperature of the extruder is set to 175-185℃, the temperature of the first zone is 155-165℃, the temperature of the second zone is 165-175℃, the temperature of the third zone is 175-185℃, and the temperature of the fourth zone is 180-190℃.

[0024] The beneficial effects of the present application are:

[0025] (1) The present application uses PBAT resin as the matrix of plastic-wood material, which can make the prepared plastic-wood material have good biodegradability, meet the development concept of contemporary ecological green environmental protection, and add the prepared flame-retardant synergist and toughening modification component to the matrix material, effectively improve the flame-retardant performance and toughness of the plastic-wood material, prolong the service life of the plastic-wood material, and broaden its application field.

[0026] (2) The present application utilizes chemical connection to graft nitrogen-phosphorus flame retardant on the surface of palygorskite to prepare a flame retardant synergist, since the palygorskite is connected by chemical bonds, the palygorskite can be uniformly dispersed in the matrix, avoiding the negative effects caused by palygorskite agglomeration, on the one hand, the palygorskite has a layered structure, which can play a role in blocking heat and oxygen transmission during material pyrolysis and combustion, forming an effective physical barrier, thereby playing a role in flame retardation, on the other hand, the nitrogen-phosphorus flame retardant grafted on the surface of the flame retardant synergist can further improve the flame retardant performance of the plastic-wood material, the nitrogen element decomposes into ammonia, nitrogen, water vapor and other non-combustible gases when heated, which helps to dilute the combustible gas and suppress the flame, the phosphorus element can decompose into phosphoric acid and polyphosphoric acid when burning to promote the formation of carbon layer, through the interaction of nitrogen and phosphorus elements, the flame retardant effect is enhanced, the occurrence of fire is avoided, and the stability and reliability of the plastic-wood material in various environments are ensured, and the application effect of the plastic-wood material in various fields is effectively improved.

[0027] (3) The present application prepares a toughening modification component as a filling modifier of the plastic-wood material, which can effectively improve the toughness of the plastic-wood material by using the flexible silicon-oxygen chain and castor oil molecules in the toughening modification component, avoiding brittle fracture, deformation or creep and other problems of the material when subjected to external impact or stress, ensuring the integrity of the material when subjected to stress and prolonging its service life, in addition, the silicon element in the toughening modification component can produce a synergistic flame retardant effect with the flame retardant synergist, further improving the flame retardant performance of the plastic-wood material.

[0028] Of course, implementing any product of the present application does not necessarily require achieving all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed for the embodiment description will be briefly introduced as follows, obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0030] Figure 1 The infrared spectrum test chart of the modified palygorskite and the flame retardant synergist prepared for the present application embodiment 1.

[0031] Figure 2 The infrared spectrum test chart of the toughening modification component prepared for the present application embodiment 1. DETAILED DESCRIPTION

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] I. Preparation of Flame Retardant Synergists

[0035] D1: Add 5g of palygorskite with an average particle size of 4μm and dimethyl sulfoxide solution to the reactor, sonicate until a uniform dispersion is formed, then add 1.2g of pyridine-3,4-dicarboxylic anhydride and 0.05g of p-toluenesulfonic acid to the dispersion. After the addition is complete, raise the temperature to 100℃, stir for 5h at this temperature, filter to separate the solid material, and obtain modified palygorskite after washing and drying.

[0036] D2: Mix 5g of modified palygorskite with N,N-dimethylformamide and ultrasonically disperse for 20min. Under continuous nitrogen conditions, add 1.4g of pentaerythritol phosphate and 0.08g of p-toluenesulfonic acid. Under stirring conditions, raise the system temperature to 105℃ and keep it at that temperature for 4h. Pour out the material and allow it to cool naturally. The solid material separated by filtration is the flame retardant synergist.

[0037] Infrared spectral analysis of the modified palygorskite and flame retardant synergist was performed using a Thermo Scientific Nicol et I S50 spectrometer. The test results are shown below. Figure 1 ,Depend on Figure 1 It can be seen that in the infrared spectrum of modified palygorskite, 1760 cm⁻¹ -1 An absorption peak appears at 1725 cm⁻¹ for the C=O group of the ester group. -1 An absorption peak for the carboxyl group C=O appears at 1630 cm⁻¹. -1 An absorption peak for C=N appears at 1405 cm⁻¹. -1 A CN absorption peak appears at 1750 cm⁻¹; in the infrared spectrum of the flame retardant synergist, the peak is at 1750 cm⁻¹. -1 An absorption peak for the C=O ester group appears at 1625 cm⁻¹, and the absorption peak for the ester group increases, reaching 1625 cm⁻¹. -1 An absorption peak for C=N appears at 1408 cm⁻¹. -1 An absorption peak for CN appears at 1281 cm⁻¹. -1 An absorption peak appears at 1170 cm⁻¹ for P=O. -1 An absorption peak for POC appears at the point, while the absorption peak for the carboxyl group disappears.

[0038] II. Preparation of toughening and modifying components

[0039] Under nitrogen protection, 4g of castor oil and 2.6g of methylphenyl dichlorosilane were added to toluene and mechanically stirred until homogeneous. Then, 0.1g of pyridine was added. After the addition was complete, heating was started. When the system temperature reached 70℃, the mixture was stirred at a constant temperature for 5 hours. The solvent was removed by rotary evaporation to obtain the toughening modified component.

[0040] Infrared spectral analysis of the toughening modification components was performed using a Thermo Scientific Nicol et I S50 spectrometer. The test results are shown in [Figure number missing]. Figure 2 ,Depend on Figure 2 It can be seen that in the infrared spectrum of the toughening and modifying component, 1741 cm⁻¹ -1 An absorption peak appears at 3010 cm⁻¹ for the C=O group of the ester group. -1 An absorption peak for the carbon-hydrogen bond in a carbon-carbon double bond appears at 3050 cm⁻¹. -1 An absorption peak for the carbon-hydrogen bonds in the benzene ring appears at 1030 cm⁻¹. -1 An absorption peak for the Si-O bond appears at the location.

[0041] III. Preparation of Wood-Plastic Composites

[0042] (1) Add 45g of PBAT resin, 30g of bamboo powder and 1g of titanate coupling agent PN-130 to a high-speed mixer and mix well. Then add 6g of flame retardant synergist, 5g of toughening modifier, 5g of talc, 1g of barium zinc composite stabilizer, 2g of zinc stearate and 0.5g of antioxidant 1076. Stir and mix at a stirring speed of 400r / min for 1h to obtain the mixture.

[0043] (2) Transfer the mixture to a twin-screw extruder for extrusion granulation. Set the extruder head temperature to 175℃, zone 1 temperature to 155℃, zone 2 temperature to 165℃, zone 3 temperature to 175℃, and zone 4 temperature to 180℃. Finally, put the extruded granules into a mold and hot-press and then cold-press to obtain wood-plastic composite material.

[0044] Example 2

[0045] Preparation of wood-plastic composite materials

[0046] (1) Add 55g of PBAT resin, 35g of bamboo powder and 1.5g of titanate coupling agent PN-130 to a high-speed mixer and mix well. Then add 8g of flame retardant synergist, 7g of toughening modifier, 8g of talc, 2g of barium zinc composite stabilizer, 3g of zinc stearate and 1g of antioxidant 1076. Stir and mix at a stirring speed of 500r / min for 1.5h to obtain the mixture.

[0047] (2) The mixed material is transferred to a twin-screw extruder for extrusion granulation, the head temperature of the extruder is set to 180°C, the temperature of the first zone is set to 160°C, the temperature of the second zone is set to 170°C, the temperature of the third zone is set to 180°C, and the temperature of the fourth zone is set to 185°C, and finally the extruded granules are placed in a mold, and the plastic wood material can be obtained by hot pressing and then cold pressing.

[0048] The preparation method of the flame-retardant synergist is the same as that in Example 1.

[0049] Example 3

[0050] Preparation of plastic wood material

[0051] (1) PBAT resin 65 g, bamboo powder 40 g, and titanate coupling agent PN-130 2 g are put into a high-speed mixer, mixed uniformly, then flame-retardant synergist 9 g, toughening modifier component 8 g, talc 10 g, barium-zinc composite stabilizer 3 g, zinc stearate 4 g, and antioxidant 1076 1.5 g are added, and stirred and mixed at a stirring speed of 600 r / min for 2 h to obtain a mixed material;

[0052] (2) The mixed material is transferred to a twin-screw extruder for extrusion granulation, the head temperature of the extruder is set to 185°C, the temperature of the first zone is set to 165°C, the temperature of the second zone is set to 175°C, the temperature of the third zone is set to 185°C, and the temperature of the fourth zone is set to 190°C, and finally the extruded granules are placed in a mold, and the plastic wood material can be obtained by hot pressing and then cold pressing.

[0053] The preparation method of the flame-retardant synergist is the same as that in Example 1.

[0054] Comparative Example 1

[0055] Preparation of plastic wood material

[0056] (1) PBAT resin 55 g, bamboo powder 35 g, and titanate coupling agent PN-130 1.5 g are put into a high-speed mixer, mixed uniformly, then flame-retardant synergist 8 g, talc 8 g, barium-zinc composite stabilizer 2 g, zinc stearate 3 g, and antioxidant 1076 1 g are added, and stirred and mixed at a stirring speed of 500 r / min for 1.5 h to obtain a mixed material;

[0057] (2) The mixed material is transferred to a twin-screw extruder for extrusion granulation, the head temperature of the extruder is set to 180°C, the temperature of the first zone is set to 160°C, the temperature of the second zone is set to 170°C, the temperature of the third zone is set to 180°C, and the temperature of the fourth zone is set to 185°C, and finally the extruded granules are placed in a mold, and the plastic wood material can be obtained by hot pressing and then cold pressing.

[0058] The preparation method of the flame-retardant synergist is the same as that in Example 1.

[0059] Comparative Example 2

[0060] Preparation of plastic-wood material

[0061] (1) Put PBAT resin 55 g, bamboo powder 35 g and titanate coupling agent PN-130 1.5 g into a high-speed mixer, mix uniformly, then add toughening modification component 7 g, talc powder 8 g, barium-zinc composite stabilizer 2 g, zinc stearate 3 g and antioxidant 1076 1 g, stir and mix at a stirring speed of 500 r / min for 1.5 h to obtain a mixture;

[0062] (2) Transfer the mixture to a twin-screw extruder for extrusion and granulation, set the die head temperature of the extruder to 180℃, the temperature of the first zone to 160℃, the temperature of the second zone to 170℃, the temperature of the third zone to 180℃ and the temperature of the fourth zone to 185℃, and finally put the extruded granules into a mold, hot-press first and then cold-press to obtain the plastic-wood material.

[0063] The preparation method of the toughening modification component is the same as that in Example 1.

[0064] Comparative Example 3

[0065] Preparation of plastic-wood material

[0066] (1) Put PBAT resin 55 g, bamboo powder 35 g and titanate coupling agent PN-130 1.5 g into a high-speed mixer, mix uniformly, then add palygorskite with an average particle size of 4 μm 8 g, toughening modification component 7 g, talc powder 8 g, barium-zinc composite stabilizer 2 g, zinc stearate 3 g and antioxidant 1076 1 g, stir and mix at a stirring speed of 500 r / min for 1.5 h to obtain a mixture;

[0067] (2) Transfer the mixture to a twin-screw extruder for extrusion and granulation, set the die head temperature of the extruder to 180℃, the temperature of the first zone to 160℃, the temperature of the second zone to 170℃, the temperature of the third zone to 180℃ and the temperature of the fourth zone to 185℃, and finally put the extruded granules into a mold, hot-press first and then cold-press to obtain the plastic-wood material.

[0068] The preparation method of the toughening modification component is the same as that in Example 1.

[0069] Comparative Example 4

[0070] Preparation of plastic-wood material

[0071] (1) Put PBAT resin 55 g, bamboo powder 35 g and titanate coupling agent PN-130 1.5 g into a high-speed mixer, mix uniformly, then add talc powder 8 g, barium-zinc composite stabilizer 2 g, zinc stearate 3 g and antioxidant 1076 1 g, stir and mix at a stirring speed of 500 r / min for 1.5 h to obtain a mixture;

[0072] (2) the mixture is transferred to a twin-screw extruder for extrusion granulation, the head temperature of the extruder is set to 180 DEG C, the temperature of the first zone is set to 160 DEG C, the temperature of the second zone is set to 170 DEG C, the temperature of the third zone is set to 180 DEG C, and the temperature of the fourth zone is set to 185 DEG C, and finally the extruded granules are placed in a mold, and the plastic-wood material can be obtained by hot pressing and then cold pressing.

[0073] Performance detection

[0074] The plastic-wood materials prepared by the examples 1-3 and the comparative examples 1-3 of the present application are made into samples meeting the specifications, the oxygen index of the samples is tested according to GB / T 2406.2-2009 "Determination of the flammability of plastics - Part 2: burning behaviour of small specimens in a vertical orientation", the elongation at break of the samples is tested according to GB / T 1040.1-2018 "Determination of the tensile properties of plastics - Part 1: general principles", and the specific detection results are shown in Table 1:

[0075] Table 1 - Performance detection

[0076] Oxygen index (%) Elongation at break (%) Example 1 33.0 25.3 Example 2 33.6 26.1 Example 3 33.2 25.6 Comparative Example 1 31.4 17.5 Comparative Example 2 28.7 24.0 Comparative Example 3 29.8 23.9 Comparative Example 4 20.5 15.3

[0077] From the test results in Table 1, it can be seen that the samples prepared by the examples 1-3 have good flame-retardant properties and toughness; the sample prepared by the comparative example 1 does not add a toughening modification component, and the toughness of the sample is poorer than that of the examples; the sample prepared by the comparative example 2 does not add a flame-retardant synergist, and the flame-retardant properties of the sample are poorer than those of the examples; the sample prepared by the comparative example 3 uses unmodified palygorskite to replace the flame-retardant synergist, and the palygorskite is not organically modified, which causes the agglomeration of the palygorskite in the matrix, resulting in a decrease in the flame-retardant properties of the sample; the sample prepared by the comparative example 4 does not add a flame-retardant synergist and a toughening modification component, and thus the various properties of the sample are poor.

[0078] The above content is only an example and description of the concept of the present application, and those skilled in the art can make various modifications or supplements to the described specific examples or use similar ways to replace them, as long as they do not deviate from the concept of the present application or exceed the scope defined by the present claims, and they should belong to the protection scope of the present application.

Claims

1. An environmentally friendly and biodegradable wood-plastic composite material, characterized in that, It is made from the following raw materials in parts by weight: 45-65 parts PBAT resin, 30-40 parts bamboo powder, 1-2 parts coupling agent, 6-9 parts flame retardant synergist, 5-8 parts toughening and modifying components, 5-10 parts filler, 1-3 parts stabilizer, 2-4 parts lubricant, and 0.5-1.5 parts antioxidant. The preparation method of the flame retardant synergist includes the following steps: D1: Add palygorskite and dimethyl sulfoxide solution to the reactor and sonicate until a uniform dispersion is formed. Then add pyridine-3,4-dicarboxylic anhydride and p-toluenesulfonic acid to the dispersion. After the addition is complete, raise the temperature to 95-105℃ and stir for 3-7 hours at this temperature. Filter to separate the solid material, and after washing and drying, obtain modified palygorskite. D2: Mix modified palygorskite with N,N-dimethylformamide and ultrasonically disperse for 15-25 minutes. Under continuous nitrogen conditions, add pentaerythritol phosphate and catalyst. Under stirring conditions, raise the system temperature to 90-110℃ and keep it at that temperature for 3-5 hours. Pour out the material and allow it to cool naturally. The solid material separated by filtration is the flame retardant synergist. The preparation method of the toughening and modifying component includes the following steps: Under nitrogen protection, castor oil and methylphenyl dichlorosilane were added to toluene and mechanically stirred until homogeneous. Then, an accelerator was added. After the addition was complete, heating was started. When the system temperature reached 65-75°C, the mixture was stirred at a constant temperature for 4-6 hours. The solvent was removed by rotary evaporation to obtain the toughening modified component.

2. The environmentally friendly and biodegradable wood-plastic composite material according to claim 1, characterized in that, In step D1, the average particle size of the palygorskite is 4 μm.

3. The environmentally friendly and biodegradable wood-plastic composite material according to claim 1, characterized in that, In step D1, the mass ratio of palygorskite to pyridine-3,4-dicarboxylic anhydride is 1:0.1 to 0.

3.

4. The environmentally friendly and biodegradable wood-plastic composite material according to claim 1, characterized in that, In step D2, the catalyst is any one of p-toluenesulfonic acid, aminosulfonic acid, or trifluoromethanesulfonic acid.

5. The environmentally friendly and biodegradable wood-plastic composite material according to claim 1, characterized in that, The accelerator is either triethylamine or pyridine.

6. A method for preparing an environmentally friendly and biodegradable wood-plastic composite material as described in claim 1, characterized in that, Includes the following steps: (1) Add PBAT resin, bamboo powder and coupling agent to a high-speed mixer, mix well, then add flame retardant synergist, toughening modifier, filler, stabilizer, lubricant and antioxidant, and stir and mix at a stirring speed of 400-600 r / min for 1-2 hours to obtain a mixture; (2) Transfer the mixture to a twin-screw extruder for extrusion granulation. Finally, put the extruded granules into a mold, and then hot-press and cold-press to obtain wood-plastic composite material.

7. The method for preparing an environmentally friendly and biodegradable wood-plastic composite material according to claim 6, characterized in that, In step (1), the filler is any one of talc, mica powder or titanium dioxide.

8. The method for preparing an environmentally friendly and biodegradable wood-plastic composite material according to claim 6, characterized in that, In step (2), the twin-screw extruder is configured with the following temperatures: extruder head temperature 175-185℃, zone 1 temperature 155-165℃, zone 2 temperature 165-175℃, zone 3 temperature 175-185℃, and zone 4 temperature 180-190℃.

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