Wood-plastic composite material for laboratory fume hood and preparation method of wood-plastic composite material

Abstract

The invention discloses a wood-plastic composite material for a laboratory fume hood and a preparation method thereof, and relates to the technical field of composite materials, and the wood-plastic composite material is prepared from the following raw materials in parts by weight: 30-40 parts of plant fiber powder, 40-50 parts of functional polycondensate, 20-30 parts of PBT resin, 10-20 parts of aromatic hyperbranched polyester, 1-2 parts of a coupling agent, 0.3-0.8 part of an antioxidant, 0.8-1.5 parts of a lubricant, and 1-2 parts of 2, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate. 1-2 parts of 2, 7-anthraquinone disulfonic acid and 1-3 parts of a catalyst A; the functional polycondensate comprises structural units introduced by the following monomers: 4, 6-hydroxy-2-cyanobenzothiazole, 2, 2-bis [4-(4-aminophenoxy) phenyl]-1, 1, 1, 3, 3, 3-hexafluoropropane and dimethyl biphenyl diisocyanate. The composite material is high in mechanical strength, sufficient in toughness and excellent in flame retardance and aging resistance.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a wood-plastic composite material for a laboratory fume hood and a preparation method thereof. Background Art

[0002] Fume hoods are a kind of local exhaust equipment commonly used in laboratories. Fume hoods can completely and timely discharge harmful gases from the workplace, prevent operators from inhaling toxic, harmful, and odorous gases, and provide good protection for operators. At present, laboratory fume hoods are generally made of plastic, wood or alloy. Alloys will be severely corroded, rusted and rotted in a short period of time under laboratory environment conditions with strong acid, alkali and water vapor; wood-type laboratory fume hoods have poor flame retardant properties, are easy to absorb water, deform, and cannot prevent insects, and excessive logging of wood will have a huge impact on the environment. Plastic laboratory fume hoods have poor weather resistance. In the natural environment, the surface loses its original luster after a period of time, fades quickly, and the exposed part is prone to aging after a period of use. It is under this situation that wood-plastic composite materials for laboratory fume hoods came into being, and its appearance has attracted widespread attention in the industry.

[0003] Wood-plastic composite materials refer to the use of polyethylene, polypropylene and polyvinyl chloride to replace the usual resin adhesives, mixed with wood powder, rice husks, straw and other waste plant fibers to form new wood materials, and then produced through plastic processing techniques such as extrusion, molding, injection molding, etc. The boards or profiles have outstanding advantages such as waterproof and moisture-proof, anti-corrosion and anti-moth, and good comprehensive mechanical properties. However, the existing wood-plastic composite materials for laboratory fume hoods still have more or less technical defects such as limited mechanical strength, flame retardancy and aging resistance still need to be further improved, and insufficient toughness.

[0004] In order to solve the above problems, the Chinese invention patent with the authorization announcement number CN117659733B discloses an environmentally friendly wood-plastic composite material and a preparation method, wherein the content of each component is: 5-15wt% bamboo powder, 45-55wt% wood powder, 25-32wt% plastic particles, 4-7wt% soybean gum, 2-5wt% auxiliary agent a, 1-5wt% auxiliary agent b, 0.2-2wt% coupling agent, 0.2-1.5wt% lubricant, 0.2-1.5wt% toughening agent. The preparation method of the wood-plastic composite material is: first weigh bamboo powder and wood powder, mix them, then weigh coupling agent, mix them and dry them to obtain a mixture A; then weigh plastic particles, soybean gum, auxiliary agent a, auxiliary agent b, lubricant and toughening agent, add them to the mixture A and mix them to obtain a mixture B; finally, the mixture B is extruded, hot pressed or injection molded to obtain the environmentally friendly wood-plastic composite material. The environmentally friendly wood-plastic composite material prepared in this application has low cost and excellent performance, which alleviates the problems of insufficient wood resources and serious plastic pollution. However, its mechanical properties and flame retardant properties still need to be further improved. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a wood-plastic composite material for laboratory fume hoods with high mechanical strength, sufficient toughness, excellent flame retardancy and aging resistance, and a preparation method thereof.

[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] A wood-plastic composite material for laboratory fume hoods is made of the following raw materials by weight: 30-40 parts of plant fiber powder, 40-50 parts of functional polycondensate, 20-30 parts of PBT resin, 10-20 parts of aromatic hyperbranched polyester, 1-2 parts of coupling agent, 0.3-0.8 part of antioxidant, 0.8-1.5 parts of lubricant, 1-2 parts of 2,7-anthraquinone disulfonic acid, 1-3 parts of catalyst A; the functional polycondensate includes structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate.

[0008] Preferably, the plant fiber powder is at least one of wood fiber powder, hemp fiber powder, bamboo fiber powder, straw fiber powder, bran powder or straw fiber powder.

[0009] Preferably, the particle size of the plant fiber powder is 50-150 mesh.

[0010] Preferably, the preparation method of the functional polycondensate includes the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting for 2-4 hours at 72-88°C in an inert gas atmosphere, then heating to 94-98°C and continuing to stir and react for 8-13 hours, then precipitating in water, washing the precipitated polymer with ethanol 3-6 times, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate.

[0011] Preferably, the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:(0.8-1.2):(6-10).

[0012] Preferably, the catalyst B is at least one of dibutyltin dilaurate and stannous octoate; the high-boiling solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; the inert gas is any one of nitrogen, helium, neon, and argon.

[0013] Preferably, the grade of the PBT resin is FRPBTG30.

[0014] Preferably, the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304, provided by Wuhan Hyperbranched Resin Technology Co., Ltd.

[0015] Preferably, the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0016] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 2246, antioxidant 168, and antioxidant 626.

[0017] Preferably, the lubricant is one or more of polyethylene wax, chlorinated polyethylene, stearic acid, zinc stearate, and calcium stearate.

[0018] Preferably, the catalyst A is composed of phosphorus pentoxide and polyphosphoric acid mixed in a mass ratio of (1 - 3):1.

[0019] Another object of the present invention is to provide a method for preparing the wood-plastic composite material for a laboratory fume hood, comprising the following steps: drying the plant fiber powder at 95 - 115°C for 1 - 3 hours, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a die to obtain the wood-plastic composite material for a laboratory fume hood.

[0020] Preferably, the extrusion temperature for the extrusion molding is 240 - 260°C, and the head pressure of the extruder is 13 - 18 MPa.

[0021] The beneficial effects of adopting the above technical solutions are as follows:

[0022] (1) The method for preparing the wood-plastic composite material for a laboratory fume hood provided by the present invention has a simple process, convenient operation and control, low dependence on equipment, high preparation efficiency and high finished product qualification rate, is suitable for continuous large-scale production, and has high popularization and application value.

[0023] (2) The wood-plastic composite material for laboratory fume hood provided by the present invention is made of the following raw materials by weight: 30-40 parts of plant fiber powder, 40-50 parts of functional polycondensate, 20-30 parts of PBT resin, 10-20 parts of aromatic hyperbranched polyester, 1-2 parts of coupling agent, 0.3-0.8 parts of antioxidant, 0.8-1.5 parts of lubricant, 1-2 parts of 2,7-anthraquinone disulfonic acid, and 1-3 parts of catalyst A; the structural units introduced by the following monomers are included in the functional polycondensate: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate. Through the mutual cooperation and joint action of the raw materials, the prepared composite material product has high mechanical strength, sufficient toughness, excellent flame retardancy and aging resistance. Using the functional polycondensate, PBT resin and aromatic hyperbranched polyester as the base materials, combining their respective advantages, the molecular structures of these raw materials all contain benzene rings. Under the catalytic action of catalyst A, they can chemically react with the sulfonic acid groups on 2,7-anthraquinone disulfonic acid to form an interpenetrating network structure, connecting these raw materials in the form of chemical bonds, thereby effectively improving the comprehensive performance and performance stability of the prepared composite material, making its mechanical strength greater, toughness more sufficient, and flame retardancy and aging resistance more excellent.

[0024] (3) For the wood-plastic composite material for laboratory fume hood provided by the present invention, the structural units introduced by the following monomers are included in the functional polycondensate: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate. By simultaneously introducing cyanobenzothiazole, fluorinated phenyl ether, urethane and urea structures into the functional polycondensate, under the multiple actions of electronic effect, steric effect and conjugate effect, etc., the prepared product has greater mechanical strength, more sufficient toughness, and more excellent flame retardancy and aging resistance; the addition of aromatic hyperbranched polyester not only has good compatibility with other raw materials, but also can effectively improve the toughness of the composite material, thereby effectively extending its service life. Detailed embodiments

[0025] In order to enable those skilled in the art to better understand the technical solutions of the present invention and make the above-mentioned features, purposes and advantages of the present invention clearer and easier to understand, the present invention will be further described below with reference to embodiments. The embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0026] Example 1

[0027] A wood-plastic composite material for a laboratory fume hood is made from the following raw materials by weight: 30 parts of plant fiber powder, 40 parts of functional polycondensate, 20 parts of PBT resin, 10 parts of aromatic hyperbranched polyester, 1 part of coupling agent, 0.3 part of antioxidant, 0.8 part of lubricant, 1 part of 2,7-anthraquinone disulfonic acid, and 1 part of catalyst A; the functional polycondensate includes structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate; the plant fiber powder is wood fiber powder; the particle size of the plant fiber powder is 50 mesh.

[0028] The preparation method of the functional polycondensate includes the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting at 72 °C for 2 hours in an inert gas atmosphere, then raising the temperature to 94 °C and continuing to stir and react for 8 hours, then precipitating in water, washing the precipitated polymer with ethanol 3 times, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate; the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:0.8:6; the catalyst B is dibutyltin dilaurate; the high-boiling solvent is N,N-dimethylformamide; the inert gas is nitrogen; through GPC test, the M n of this functional polycondensate is measured to be 14370 g / mol, and M W / M n is 1.318; through elemental analysis and weight change calculation, the molar ratio of the structural units introduced by 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate in this functional polycondensate is the same as the theoretical value.

[0029] The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is end-hydroxyl aromatic hyperbranched polyester HyPer H304 provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; the coupling agent is silane coupling agent KH550; the antioxidant is antioxidant 1010; the lubricant is polyethylene wax; the catalyst A is a mixture of phosphorus pentoxide and polyphosphoric acid in a mass ratio of 1:1.

[0030] A preparation method of the wood-plastic composite material for the laboratory fume hood comprises the following steps: drying plant fiber powder at 95 °C for 1 hour, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a mold to obtain the wood-plastic composite material for the laboratory fume hood; the extrusion temperature for the extrusion molding is 240 °C, and the head pressure of the extruder is 13 MPa.

[0031] Example 2

[0032] A wood-plastic composite material for a laboratory fume hood is made from the following raw materials by weight: 33 parts of plant fiber powder, 42 parts of functional polycondensate, 23 parts of PBT resin, 12 parts of aromatic hyperbranched polyester, 1.2 parts of coupling agent, 0.5 part of antioxidant, 1 part of lubricant, 1.2 parts of 2,7-anthraquinone disulfonic acid, and 1.5 parts of catalyst A; the functional polycondensate includes structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate; the plant fiber powder is hemp fiber powder; the particle size of the plant fiber powder is 80 mesh.

[0033] The preparation method of the functional polycondensate comprises the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting at 76 °C for 2.5 hours in an inert gas atmosphere, then heating up to 95 °C and continuing to stir and react for 10 hours, then precipitating in water, washing the precipitated polymer with ethanol 4 times, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate; the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:0.9:7; the catalyst B is stannous octoate; the high-boiling solvent is dimethyl sulfoxide; the inert gas is helium.

[0034] The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304 provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; the coupling agent is a silane coupling agent KH560; the antioxidant is antioxidant 1076; the lubricant is chlorinated polyethylene; the catalyst A is composed of phosphorus pentoxide and polyphosphoric acid mixed according to a mass ratio of 1.5:1.

[0035] A preparation method of the wood-plastic composite material for the laboratory fume hood comprises the following steps: drying the plant fiber powder at 100 °C for 1.5 hours, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a die to obtain the wood-plastic composite material for the laboratory fume hood; the extrusion temperature for the extrusion molding is 245 °C, and the head pressure of the extruder is 15 MPa.

[0036] Example 3

[0037] A wood-plastic composite material for a laboratory fume hood is made from the following raw materials by weight: 35 parts of plant fiber powder, 45 parts of functional polycondensate, 25 parts of PBT resin, 15 parts of aromatic hyperbranched polyester, 1.5 parts of coupling agent, 0.5 part of antioxidant, 1.2 parts of lubricant, 1.5 parts of 2,7-anthraquinone disulfonic acid, and 2 parts of catalyst A; the functional polycondensate includes structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate; the plant fiber powder is bamboo fiber powder; the particle size of the plant fiber powder is 100 mesh.

[0038] The preparation method of the functional polycondensate comprises the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting at 82 °C for 3 hours in an inert gas atmosphere, then raising the temperature to 96 °C and continuing to stir and react for 11 hours, then precipitating in water, washing the precipitated polymer 5 times with ethanol, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate; the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:1:8; the catalyst B is a mixture of dibutyltin dilaurate and stannous octoate in a mass ratio of 2:3; the high-boiling solvent is a mixture of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone in a mass ratio of 1:2:1; the inert gas is neon.

[0039] The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304 provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; the coupling agent is a mixture of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570 in a mass ratio of 1:1:2; the antioxidant is a mixture of antioxidant 1010, antioxidant 1076, antioxidant 2246, antioxidant 168, and antioxidant 626 in a mass ratio of 2:2:3:1:5; the lubricant is a mixture of polyethylene wax, chlorinated polyethylene, stearic acid, zinc stearate, and calcium stearate in a mass ratio of 1:1:2:1:1; the catalyst A is a mixture of phosphorus pentoxide and polyphosphoric acid in a mass ratio of 2:1.

[0040] A preparation method of the wood-plastic composite material for a laboratory fume hood comprises the following steps: drying the plant fiber powder at 105 °C for 2 hours, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a die to obtain the wood-plastic composite material for a laboratory fume hood; the extrusion temperature for the extrusion molding is 250 °C, and the head pressure of the extruder is 16 MPa.

[0041] Example 4

[0042] A wood-plastic composite material for a laboratory fume hood is made from the following raw materials by weight: 38 parts of plant fiber powder, 48 parts of functional polycondensate, 28 parts of PBT resin, 18 parts of aromatic hyperbranched polyester, 1.8 parts of coupling agent, 0.7 part of antioxidant, 1.3 parts of lubricant, 1.8 parts of 2,7-anthraquinone disulfonic acid, and 2.5 parts of catalyst A; the functional polycondensate includes the structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and dimethylbiphenyl diisocyanate; the plant fiber powder is a mixture of wood fiber powder, hemp fiber powder, bamboo fiber powder, straw fiber powder, and bran powder in a mass ratio of 2:1:1:2:3; the particle size of the plant fiber powder is 140 mesh.

[0043] The preparation method of the functional polycondensate includes the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting at 86 °C for 3.5 hours under an inert gas atmosphere, then heating to 97 °C and continuing to stir and react for 12 hours, then precipitating in water, washing the precipitated polymer with ethanol 6 times, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate; the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:1.2:10; the catalyst B is dibutyltin dilaurate; the high-boiling solvent is dimethyl sulfoxide; the inert gas is nitrogen.

[0044] The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304 provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; the coupling agent is a silane coupling agent KH560; the antioxidant is antioxidant 2246; the lubricant is zinc stearate; the catalyst A is composed of phosphorus pentoxide and polyphosphoric acid mixed according to a mass ratio of 2.5:1.

[0045] A preparation method of the wood-plastic composite material for a laboratory fume hood includes the following steps: drying the plant fiber powder at 112 °C for 2.5 hours, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a mold to obtain the wood-plastic composite material for a laboratory fume hood; the extrusion temperature for the extrusion molding is 255 °C, and the head pressure of the extruder is 17 MPa.

[0046] Example 5

[0047] A wood-plastic composite material for a laboratory fume hood is made of the following raw materials by weight: 40 parts of plant fiber powder, 50 parts of functional polycondensate, 30 parts of PBT resin, 20 parts of aromatic hyperbranched polyester, 2 parts of coupling agent, 0.8 part of antioxidant, 1.5 parts of lubricant, 2 parts of 2,7-anthraquinone disulfonic acid, and 3 parts of catalyst A; the functional polycondensate includes structural units introduced by the following monomers: 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate; the plant fiber powder is straw fiber powder; the particle size of the plant fiber powder is 150 mesh.

[0048] The preparation method of the functional polycondensate comprises the following steps: adding 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, and catalyst B into a high-boiling solvent, stirring and reacting at 88 °C for 4 hours under an inert gas atmosphere, then raising the temperature to 98 °C and continuing to stir and react for 13 hours, then precipitating in water, washing the precipitated polymer with ethanol 6 times, and then rotary evaporating to remove the residual solvent to obtain the functional polycondensate; the molar ratio of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high-boiling solvent is 0.7:0.3:1:1.2:10; the catalyst B is dibutyltin dilaurate; the high-boiling solvent is N-methylpyrrolidone; the inert gas is nitrogen.

[0049] The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304 provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; the coupling agent is a silane coupling agent KH560; the antioxidant is antioxidant 1010; the lubricant is stearic acid; the catalyst A is composed of phosphorus pentoxide and polyphosphoric acid mixed in a mass ratio of 3:1.

[0050] A preparation method of the wood-plastic composite material for a laboratory fume hood comprises the following steps: drying plant fiber powder at 115 °C for 3 hours, then mixing it evenly with other raw materials, adding it into an extruder, and extruding and molding through a die to obtain the wood-plastic composite material for a laboratory fume hood; the extrusion temperature for the extrusion molding is 260 °C, and the head pressure of the extruder is 18 MPa.

[0051] Comparative Example 1

[0052] A wood-plastic composite material for a laboratory fume hood and its preparation method are basically the same as those in Example 1, except that an equal amount of 4,6-dihydroxy-2-cyanobenzothiazole is used to replace 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane.

[0053] Comparative Example 2

[0054] A wood-plastic composite material for a laboratory fume hood and its preparation method are basically the same as those in Example 1, except that an equal amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane is used to replace 4,6-dihydroxy-2-cyanobenzothiazole.

[0055] Comparative Example 3

[0056] A wood-plastic composite material for laboratory fume hoods and its preparation method are basically the same as those in Example 1, except that 2,7-anthraquinone disulfonic acid is not added.

[0057] The wood-plastic composite materials for laboratory fume hoods prepared in Examples 1-5 and Comparative Examples 1-3 were respectively subjected to performance tests. The test results are shown in Table 1. The test method refers to GB / T 29418-2023, and the flame retardancy grade refers to UL94-2023.

[0058] Table 1

[0059] Test Items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Flexural Strength (MPa) 167 170 172 176 178 155 147 132 Falling Hammer Impact Method A Pass Pass Pass Pass Pass Fail Fail Fail Flame Retardant Grade V-0 V-0 V-0 V-0 V-0 V-1 V-1 V-1 Aging Resistance Performance (%) 99.29 99.45 99.65 99.78 99.95 98.87 98.93 94.75

[0060] Among them, for the aging resistance performance, the wood-plastic composite materials for laboratory fume hoods involved in each example were placed in hot air at 90 °C for artificial accelerated aging for 150 hours, then cooled to room temperature, and the flexural strength test was carried out again, and the retention rate of the flexural strength was calculated. The larger the value, the better the aging resistance performance.

[0061] As can be seen from Table 1, compared with the comparative examples, the wood-plastic composite materials for laboratory fume hoods disclosed in the examples of the present invention have better mechanical strength, toughness, flame retardancy and aging resistance; the combined use of 4,6-dihydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and 2,7-anthraquinone disulfonic acid is beneficial to improving the above performances.

[0062] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims

1. A wood-plastic composite material for laboratory fume hoods, characterized in that: The invention is prepared from the following raw materials in parts by weight: 30-40 parts of plant fiber powder, 40-50 parts of functional polycondensate, 20-30 parts of PBT resin, 10-20 parts of aromatic hyperbranched polyester, 1-2 parts of coupling agent, 0.3-0.8 parts of antioxidant, 0.8-1.5 parts of lubricant, 1-2 parts of 2,7-anthraquinone disulfonic acid and 1-3 parts of catalyst A; the functional polycondensate comprises structural units introduced by the following monomers: 4,6-hydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and dimethylbiphenyl diisocyanate.

2. The wood-plastic composite material for laboratory fume hoods according to claim 1, characterized in that: The plant fiber powder is at least one of wood fiber powder, hemp fiber powder, bamboo fiber powder, grass fiber powder, bran powder or straw fiber powder.

3. The wood-plastic composite material for laboratory fume hoods according to claim 1, characterized in that: The particle size of the plant fiber powder is 50-150 meshes.

4. The wood-plastic composite material for laboratory fume hoods according to claim 1, characterized in that: The preparation method of the functional polycondensate comprises the following steps: adding 4,6-hydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate and catalyst B into a high boiling point solvent, stirring and reacting for 2-4 hours at 72-88°C in an inert gas atmosphere, then heating to 94-98°C and continuing stirring and reacting for 8-13 hours, then precipitating in water, washing the precipitated polymer with ethanol for 3-6 times, and then removing the residual solvent by rotary evaporation to obtain the functional polycondensate.

5. The wood-plastic composite material for laboratory fume hoods according to claim 4, characterized in that: The molar ratio of the 4,6-hydroxy-2-cyanobenzothiazole, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, dimethylbiphenyl diisocyanate, catalyst B, and high boiling point solvent is 0.7:0.3:1:(0.8-1.2):(6-10).

6. The wood-plastic composite material for laboratory fume hoods according to claim 4, characterized in that: The catalyst B is at least one of dibutyltin dilaurate and stannous octoate; the high boiling point solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone; and the inert gas is any one of nitrogen, helium, neon and argon.

7. The wood-plastic composite material for laboratory fume hoods according to claim 1, characterized in that: The grade of the PBT resin is FRPBTG30; the aromatic hyperbranched polyester is a hydroxyl-terminated aromatic hyperbranched polyester HyPer H304; and the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

8. The wood-plastic composite material for laboratory fume hoods according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 2246, antioxidant 168, and antioxidant 626; the lubricant is one or more of polyethylene wax, chlorinated polyethylene, stearic acid, zinc stearate, and calcium stearate; and the catalyst A is a mixture of phosphorus pentoxide and polyphosphoric acid in a mass ratio of (1-3):

1.

9. A method for preparing a wood-plastic composite material for a laboratory fume hood according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: drying the plant fiber powder at 95-115°C for 1-3 hours, then uniformly mixing the plant fiber powder with other raw materials, adding the powder into an extruder, and extruding the powder through a mold to obtain a wood-plastic composite material for a laboratory fume hood.

10. The method for preparing a wood-plastic composite material for a laboratory fume hood according to claim 9, characterized in that: The extrusion temperature of the extrusion molding is 240-260° C., and the head pressure of the extruder is 13-18 MPa.