CN102093735B - Wood flour/polypropylene wood-plastic composite material using silane modified ammonium polyphosphate as fire retardant and preparation method thereof - Google Patents

Abstract

A wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant and a preparation method thereof, relating to a wood powder/polypropylene wood-plastic composite material and a preparation method thereof. The invention solves the problems of poor compatibility, low mechanical properties, poor flame retardancy and poor heat resistance of the existing wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant. The wood-plastic composite material is made of wood powder, polypropylene, silane-modified ammonium polyphosphate, m-TMI-g-PP coupling agent and antioxidant, and the silane-modified ammonium polyphosphate is made of ammonium polyphosphate and γ- Made from methacryloxypropyltrimethoxysilane. Preparation method: Prepare silane-modified ammonium polyphosphate, then mix wood powder, polypropylene, silane-modified ammonium polyphosphate, m-TMI-g-PP coupling agent and antioxidant, and extrude through twin-screw extruder That's it. The wood-plastic composite material of the invention has good flame-retardant performance, high mechanical performance, good heat resistance performance and simple process.

Description

A wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant and its preparation method

technical field

The invention relates to a wood powder/polypropylene wood-plastic composite material and a preparation method thereof, in particular to a wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant and a preparation method thereof.

Background technique

Wood-plastic composite material is an environmentally friendly new material formed by using different component forms of agricultural and forestry waste wood raw materials and plastic or recycled plastic through recombination and compounding. Since the 1990s, wood-plastic composite materials have developed very rapidly, and they are mainly used in outdoor decoration, corridor panels, stairs, guardrails and a small amount of civilian consumer products. Wood-plastic composite materials can make full use of waste wood materials and waste plastic materials that are difficult to degrade, and provide a new solution to alleviate the current shortage of wood resources and the recycling of waste plastics. When selecting plastic raw materials for wood-plastic composite materials, the characteristics of accelerated pyrolysis of wood fiber materials above 200°C must be considered, and the melting point of plastic materials should not be too high. The most commonly used plastic varieties include high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC). Except for PVC, wood fiber materials and the other three types of plastics are flammable materials. Without flame retardant treatment, they cannot meet the requirements of the fire protection code for interior decoration design of buildings, and there are certain fire hazards when used indoors. As a new and widely used material, wood-plastic composite material is one of the important means to expand its application range and diversify its products by studying its combustion characteristics and reasonable flame-retardant treatment.

Although traditional halogen-based flame retardants have good flame-retardant effects, due to the release of toxic and corrosive hydrogen halide gas during the flame-retardant process, the harm to the environment and humans cannot be ignored. Therefore, the development of halogen-free flame-retardant technology has become a One of the hotspots in the field of fuel research. Among the low-smoke and halogen-free phosphorus flame retardants, the application research of ammonium polyphosphate (APP) is the most attractive. Because of its high phosphorus and nitrogen content, phosphorus-nitrogen can exert a synergistic flame retardant effect. However, the research shows that because APP is a highly polar polymer, its dispersion and bonding in wood-plastic composite materials are not good, so the mechanical properties of the composite material will decrease after adding APP, and the tensile strength of the composite material will decrease. Tensile strength, bending strength and impact strength are all significantly decreased. At the same time, studies have shown that the flame retardancy of APP on wood-plastic composite materials is not good, and the addition amount is high, which has a certain impact on the processing and mechanical properties of wood-plastic composite materials.

Contents of the invention

The purpose of the present invention is to solve the problems of poor compatibility, low mechanical properties, poor flame retardancy and poor heat resistance of existing wood powder/polypropylene wood-plastic composite materials that use ammonium polyphosphate as a flame retardant. Provided is a wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant and a preparation method thereof, which has good compatibility, mechanical properties, heat resistance and flame retardancy at the same time. wood-plastic composite materials.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as flame retardant of the present invention consists of 50-70 parts of wood powder, 30-50 parts of polypropylene, 15-30 parts of silane modified Ammonium polyphosphate (M-APP), 3 to 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 0.1 to 1 parts It is made of antioxidant, and the silane-modified ammonium polyphosphate is made of 80-100 parts of ammonium polyphosphate and 0.5-2 parts of γ-methacryloxypropyl trimethoxysilane in parts by weight.

The preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as flame retardant of the present invention is realized through the following steps: 1. Mix 80-100 parts of ammonium polyphosphate, 0.5- Put 2 parts of γ-methacryloxypropyltrimethoxysilane and absolute ethanol into a three-necked flask, stir at 60°C for 1 hour, then filter with suction, and then put the filter cake in an oven at 105°C Drying at lower temperature for 3 hours to obtain silane-modified ammonium polyphosphate (M-APP), wherein the ratio of the weight of ammonium polyphosphate to the volume of absolute ethanol is 80-100g: 150mL; 2. Weigh the following raw materials in parts by weight: 50-70 Parts of wood flour, 30-50 parts of polypropylene, 15-30 parts of silane-modified ammonium polyphosphate prepared in step 1, 3-6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene Coupling agent and 0.1 to 1 part of antioxidant; 3. Mix and stir the raw materials weighed in step 2 to obtain a mixture, and then input the mixture into a feeder with metering, and adjust the feeding speed to 5r min ^-1 , and then sent into the twin-screw extruder, set the screw temperature of each section of the twin-screw extruder from the feed port to the machine head to be 160°C, 170°C, 170°C, 180°C, 180°C, 175°C ℃, 165℃, 160℃, the screw speed is 40r·min ^-1 , the length-to-diameter ratio of the twin-screw extruder is 35:1, after the mixture is extruded by the twin-screw extruder, it can be cooled to obtain silane-modified polymer Ammonium phosphate as flame retardant wood flour/polypropylene wood-plastic composites.

The present invention uses silane coupling agent (γ-methacryloxypropyltrimethoxysilane, KH-570) modified ammonium polyphosphate (abbreviated as M-APP) as a halogen-free flame retardant, greatly improving wood The flame retardancy, physical and mechanical properties and heat resistance of the powder/polypropylene composite material have improved the compatibility between the silane-modified ammonium polyphosphate and wood flour, making the new material better than the existing ones in all aspects. Some flame retardant wood flour / polypropylene composites.

The present invention uses KH-570 to modify ammonium polyphosphate, and KH-570 improves the interfacial compatibility and dispersibility of ammonium polyphosphate (APP), improves the dispersibility and binding ability of APP in composite materials, thereby improving the composite The mechanical properties of the material.

In the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as flame retardant of the present invention, during the heating process, silane-modified ammonium polyphosphate (M-APP) releases phosphoric acid, HPO free radicals, PO free radicals radicals, Si-O, Si-C and organic groups, etc., they can capture the free radicals released by wood powder, accelerate the decomposition of wood powder into charcoal, and advance the decomposition time of wood powder, so that polypropylene becomes stable and delays Decomposition achieves flame retardant effect. At the same time, M-APP can promote the formation of charcoal layer, prevent heat transfer and flammable gas exchange in the combustion process, and can protect the stability of polypropylene at high temperature and delay its decomposition temperature. It can be seen that adding M-APP flame retardant makes the compound The thermal degradation behavior of the material is better improved.

The wood powder/polypropylene wood-plastic composite material (abbreviated as M-APP wood powder/PP material) of the present invention using silane-modified ammonium polyphosphate as a flame retardant has good mechanical properties, and the tensile strength is 24.93-28.04MPa , the bending strength is 61.98-65.68MPa, and the impact strength is 4.11-5.75kJ/m ² ; while the existing wood powder/polypropylene wood-plastic composite material (abbreviated as APP wood powder/PP) with ammonium polyphosphate as flame retardant Material, made by weight of 25 parts of APP, 60 parts of wood powder, 40 parts of PP, 6 parts of m-TMI-g-PP coupling agent and 1 part of antioxidant) the tensile strength is 21.88MPa, and the bending strength is 59.87MPa, and the impact strength is 3.39kJ/m ² ; the tensile strength of wood powder/polypropylene wood-plastic composite material (referred to as wood powder/PP material) without flame retardant is 23.27MPa, and the bending strength is 60.29 MPa, the impact strength is 3.94kJ/m ² . Visible, the mechanical property of M-APP wood powder/PP material of the present invention is better than the mechanical property of existing APP wood powder/PP material and wood powder/PP material, has solved existing due to the addition of ammonium polyphosphate flame retardant The problem of the decline in the mechanical properties of wood flour/PP materials.

The M-APP wood powder/PP material of the present invention has good heat resistance, shortens the initial decomposition time, and promotes the charcoal formation of the M-APP wood powder/PP material. The temperature (T _1wt% ) when the weight loss of the M-APP wood flour/PP material of the present invention is 1% is 102.3-108.3°C, the highest decomposition peak temperature value (T _max1 ) is 322.9-339.2°C, and the highest decomposition peak of polypropylene The temperature value (T _max2 ) is 499.6-519.6°C, and the residual carbon mass at 800°C is 21.3%-22.7%. It is better than the existing wood powder/polypropylene wood-plastic composite material with ammonium polyphosphate as flame retardant (25 parts by weight of APP, 60 parts of wood powder, 40 parts of PP, 6 parts of m-TMI-g-PP even The heat resistance performance (T _1wt% is 110.7°C, T _max1 is 329.3°C, T _max2 is 518.0°C and the carbon residue mass is 20.5% at 800°C) heat resistance performance.

The M-APP wood flour/PP material of the present invention has good flame retardancy, the limiting oxygen index is 28.3%-30.7%, the ignition time (TTI) is 36-56s, and the heat release rate (HRR) is small, 154.9-169.7kW /m ² , the total heat release (THR) value is small, 57.2-62.2MJ/m ² . All are better than the existing wood powder/polypropylene wood-plastic composite material (by weight of 25 parts of APP, 60 parts of wood powder, 40 parts of PP, 6 parts of m-TMI-g-PP) with ammonium polyphosphate as flame retardant coupling agent and 1 part antioxidant) flame retardancy (limiting oxygen index is 27.4%, TTI is 28s, HRR is 196.2kW/m ² , THR is 72MJ/m ² ).

In summary, the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant of the present invention has the advantages of good flame retardancy, high mechanical properties, and good heat resistance; at the same time, the preparation of the present invention The method and process are simple.

Description of drawings

Fig. 1 is the heat release rate (HRR)-time (s) curve figure of the wood powder/polypropylene wood-plastic composite material of embodiment 14, 15 and 16 using silane-modified ammonium polyphosphate as flame retardant , the curve 1 in the figure is the fourteenth embodiment, the curve 2 is the fifteenth embodiment, and the curve 3 is the sixteenth embodiment;

Fig. 2 is the total heat release (THR)-time (s) curve figure of the wood flour/polypropylene wood-plastic composite material of embodiment 14, 15 and 16, and curve 1 among the figure is embodiment 14 The curve 2 is the fifteenth embodiment, and the curve 3 is the sixteenth embodiment;

Fig. 3 is the total smoke emission (TSP)-time (s) curve figure of the wood flour/polypropylene wood-plastic composite material of embodiment 14, 15 and 16, and curve 1 among the figure is embodiment 14 The curve 2 is the fifteenth embodiment, and the curve 3 is the sixteenth embodiment;

Fig. 4 is the thermogravimetric curve diagram of the wood flour/polypropylene wood-plastic composite material of embodiment 16, 17 and 18, curve 1 among the figure is embodiment 16, and curve 2 is embodiment 17 , curve 3 is the eighteenth of the specific embodiment;

Fig. 5 is the derivative thermogravimetric curve of wood powder/polypropylene wood-plastic composite material of embodiment 16, 17 and 18, curve 1 among the figure is embodiment 16, and curve 2 is embodiment Seventeen, the curve 3 is the eighteenth specific embodiment;

Fig. 6 is the heat release rate (HRR)-time (s) curve figure of the wood flour/polypropylene wood-plastic composite material of embodiment 16, 17 and 18, and curve 1 among the figure is embodiment 17 , curve 2 is the eighteenth embodiment, and curve 3 is the sixteenth embodiment;

Fig. 7 is the total heat release (THR)-time (s) curve figure of the wood powder/polypropylene wood-plastic composite material of embodiment 16, 17 and 18, and curve 1 among the figure is embodiment 17 The curve 2 is the eighteenth embodiment, and the curve 3 is the sixteenth embodiment;

Fig. 8 is the total smoke emission (TSP)-time (s) graph of the wood powder/polypropylene wood-plastic composite material of embodiment 16, 17 and 18, and curve 1 among the figure is embodiment 17 The curve 2 is the eighteenth embodiment, and the curve 3 is the sixteenth embodiment;

Fig. 9 is the scanning electron micrograph of the surface charcoal layer after the fire retardant performance test of wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as flame retardant in embodiment sixteen;

Fig. 10 is a scanning electron micrograph of the surface charcoal layer of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant according to the seventeenth embodiment after the flame retardant performance test.

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific embodiment one: this embodiment is the wood powder/polypropylene wood-plastic composite material that uses silane-modified ammonium polyphosphate as a flame retardant, which consists of 50-70 parts of wood powder, 30-50 parts of polypropylene, 15-30 parts of silane-modified ammonium polyphosphate (M-APP), 3-6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) The silane-modified ammonium polyphosphate is made of 80-100 parts of ammonium polyphosphate and 0.5-2 parts of γ-methacryloxypropyl trimethoxy made from silane.

The wood powder/polypropylene wood-plastic composite material of this embodiment using silane-modified ammonium polyphosphate as a flame retardant has good mechanical properties, with a tensile strength of 24.93-28.04MPa, a bending strength of 61.98-65.68MPa, and an impact strength of 4.11～5.75kJ/m ² ; heat resistance is good, the temperature (T _1wt% ) at 1% weight loss is 102.3～108.3℃, the highest decomposition peak temperature value (T _max1 ) is 322.9～339.2℃, and the decomposition of polypropylene is the most The peak temperature value (T _max2 ) is 499.6-519.6°C, and the carbon residue mass at 800°C is 21.3%-22.7%; the flame retardancy is good, the limiting oxygen index is 28.3%-30.7%, and the ignition time (TTI) is 36-36% At 56s, the heat release rate (HRR) is small, ranging from 154.9 to 169.7kW/m ² , and the total heat release (THR) is small, ranging from 57.2 to 62.2MJ/m ² .

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance.

Specific embodiment two: the difference between this embodiment and specific embodiment one is by weight by 60 parts of wood flour, 40 parts of polypropylene, 20 parts of silane modified ammonium polyphosphate, 6 parts of m-isopropenyl-α, α - Made of dimethyl benzyl isocyanate grafted polypropylene coupling agent and 1 part antioxidant. Other parameters are the same as in the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment one is that by weight, 60 parts of wood flour, 40 parts of polypropylene, 25 parts of silane modified ammonium polyphosphate, 6 parts of m-isopropenyl-α, α - Made of dimethyl benzyl isocyanate grafted polypropylene coupling agent and 1 part antioxidant. Other parameters are the same as in the first embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 1, 2 or 3 is that the silane-modified ammonium polyphosphate is composed of 90 to 100 parts of ammonium polyphosphate and 1 to 2 parts of γ-methylacrylic acid in parts by weight. Acyloxypropyltrimethoxysilane. Other parameters are the same as those in Embodiment 1, 2 or 3.

Embodiment 5: The difference between this embodiment and Embodiment 1, 2 or 3 is that the silane-modified ammonium polyphosphate is composed of 100 parts of ammonium polyphosphate and 1.5 parts of γ-methacryloxypropane in parts by weight. made from trimethoxysilane. Other parameters are the same as those in Embodiment 1, 2 or 3.

Embodiment 6: This embodiment is different from Embodiment 1 to Embodiment 5 in that the antioxidant is antioxidant 1010 , antioxidant 1076 or antioxidant 168 . Other steps and parameters are the same as one of the specific embodiments 1 to 5.

Embodiment 7: This embodiment is the preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant described in Embodiment 1, which is realized through the following steps: 1. Put 80-100 parts of ammonium polyphosphate, 0.5-2 parts of γ-methacryloxypropyl trimethoxysilane and absolute ethanol into a three-necked bottle by weight, stir at 60°C for 1 hour, and then Suction filtration, then put the filter cake in an oven, and dry at 105°C for 3 hours to obtain silane-modified ammonium polyphosphate (M-APP), wherein the ratio of the weight of ammonium polyphosphate to the volume of absolute ethanol is 80-100g : 150mL; 2. Take the following raw materials by weight: 50-70 parts of wood flour, 30-50 parts of polypropylene, 15-30 parts of silane-modified ammonium polyphosphate prepared in step 1, 3-6 parts of m-isopropylene base-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 0.1 to 1 part of antioxidant; 3. Mix and stir the raw materials weighed in step 2 to obtain a mixture, and then input the mixture into the belt In the metered feeder, adjust the feeding speed to 5r·min ^-1 , and then feed it into the twin-screw extruder. Set the temperature of each section of the twin-screw extruder from the feeding port to the head of the machine. 160°C, 170°C, 170°C, 180°C, 180°C, 175°C, 165°C, 160°C, the screw speed is 40r·min ^-1 , the length-to-diameter ratio of the twin-screw extruder is 35:1, and the mixture is made of After being extruded by a twin-screw extruder, the wood powder/polypropylene wood-plastic composite material can be obtained by cooling with silane-modified ammonium polyphosphate as a flame retardant.

The preparation method of this embodiment has a simple process. The prepared wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant has the advantages of good flame retardancy, high mechanical performance and good heat resistance. Good mechanical properties, tensile strength is 24.93-28.04MPa, bending strength is 61.98-65.68MPa, impact strength is 4.11-5.75kJ/m ² ; heat resistance is good, the temperature (T _1wt% ) when the weight loss is 1% is 102.3～108.3℃, the highest decomposition peak temperature (T _max1 ) is 322.9～339.2℃, the highest polypropylene decomposition peak temperature (T _max2 ) is 499.6～519.6℃, and the residual charcoal mass at 800℃ is 21.3%～22.7% ;Good flame retardancy, limiting oxygen index is 28.3%~30.7%, ignition time (TTI) is 36~56s, heat release rate (HRR) is small, 154.9~169.7kW/m ² , total heat release (THR) The value is small, 57.2～62.2MJ/m ² .

The standards of the parts by weight in step 1 and step 2 in this embodiment can be different.

Embodiment 8: The difference between this embodiment and Embodiment 7 is that in step 1, 90 to 100 parts of ammonium polyphosphate, 1 to 2 parts of γ-methacryloxypropyl trimethoxysilane and Anhydrous ethanol was put into a three-necked bottle. Other steps and parameters are the same as those in Embodiment 7.

Specific embodiment nine: the difference between this embodiment and specific embodiment seven is that in step 1, 100 parts of ammonium polyphosphate, 1.5 parts of γ-methacryloxypropyl trimethoxysilane and absolute ethanol are put into into the three-neck bottle. Other steps and parameters are the same as those in Embodiment 7.

Embodiment 10: The difference between this embodiment and Embodiment 7, 8 or 9 is that the following raw materials are weighed by weight in step 2: 60 parts of wood powder, 40 parts of polypropylene, 20 parts of silane modified prepared in step 1 Ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part of antioxidant. Other steps and parameters are the same as those in Embodiment 7, 8 or 9.

Embodiment 11: The difference between this embodiment and Embodiment 7, 8 or 9 is that the following raw materials are weighed by weight in step 2: 60 parts of wood powder, 40 parts of polypropylene, 25 parts of silane modification prepared in step 1 Ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part of antioxidant. Other steps and parameters are the same as those in Embodiment 7, 8 or 9.

Embodiment 12: The difference between this embodiment and Embodiment 7, 8 or 9 is that the following raw materials are weighed by weight in step 2: 60 parts of wood powder, 40 parts of polypropylene, 15 parts of silane modification prepared in step 1 Ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part of antioxidant. Other steps and parameters are the same as those in Embodiment 7, 8 or 9.

Embodiment 13: The difference between this embodiment and Embodiment 7, 8 or 9 is that the following raw materials are weighed by weight in step 2: 60 parts of wood flour, 40 parts of polypropylene, 30 parts of silane modified in step 1 Ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part of antioxidant. Other steps and parameters are the same as those in Embodiment 7, 8 or 9.

Specific embodiment fourteen: present embodiment is the wood flour/polypropylene wood-plastic composite material that uses silane-modified ammonium polyphosphate as flame retardant, and it is made of 60g wood flour, 40g polypropylene, 15g silane-modified ammonium polyphosphate ( M-APP), 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010, the silane The modified ammonium polyphosphate is made from 100 g of ammonium polyphosphate and 1.5 g of γ-methacryloxypropyltrimethoxysilane.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, tensile strength is 26.62MPa, bending strength is 64.25MPa, impact strength is 4.90kJ/m ² ; heat resistance is good, the temperature (T _1wt% ) when the weight loss is 1% is 108.3℃, and the highest decomposition peak The temperature value (T _max1 ) is 339.2°C, the highest peak temperature value (T _max2 ) of polypropylene decomposition is 499.6°C, and the residual carbon mass at 800°C is 21.3%; the flame retardancy is good, the limiting oxygen index is 28.3%, and the ignition time (TTI) up to 36s, the heat release rate (HRR) is small at 169.7kW/m ² , and the total heat release (THR) is small at 62.2MJ/m ² .

The heat release rate (HRR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 1 in FIG. 1 .

The total heat release (THR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 1 in FIG. 2 .

The total smoke release (TSP)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 1 in FIG. 3 .

The preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is realized through the following steps: 1. Mix 100g ammonium polyphosphate, 1.5g gamma- Put methacryloxypropyltrimethoxysilane and 150mL absolute ethanol into a three-necked flask, stir at 60°C for 1 hour, then filter with suction, then put the filter cake in an oven and dry it at 105°C 3h to obtain silane-modified ammonium polyphosphate (M-APP); 2. Take the following raw materials by weight: 60g wood flour, 40g polypropylene, 15g silane-modified ammonium polyphosphate prepared in step 1, 6g m-isopropylene Base-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1g antioxidant 1010; 3. Mix and stir the raw materials weighed in step 2 to obtain a mixture, and then input the mixture into the metering In the feeder, adjust the feeding speed to 5r·min ^-1 , and then feed it into the twin-screw extruder, and set the screw temperature of each section of the twin-screw extruder from the feeding port to the machine head to be 160°C ^. After being extruded by the extruder, the wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as the flame retardant can be obtained after cooling.

Embodiment 15: This embodiment is different from Embodiment 14 in that the wood flour/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as a flame retardant consists of 60g wood flour, 40g polypropylene, and 20g silane Modified ammonium polyphosphate (M-APP), 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010 production. Other parameters are the same as in the fourteenth embodiment.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, tensile strength is 27.1MPa, bending strength is 65.68MPa, impact strength is 5.50kJ/m ² ; heat resistance is good, the temperature (T _1wt% ) when the weight loss is 1% is 104.7℃, and the highest decomposition peak The temperature value (T _max1 ) is 326.7°C, the highest peak temperature value (T _max2 ) of polypropylene decomposition is 512.3°C, and the mass of char residue at 800°C is 22%; the flame retardancy is good, the limiting oxygen index is 29.5%, and the ignition time (TTI) up to 54s, the heat release rate (HRR) is small at 158.7kW/m ² , and the total heat release (THR) is small at 58.8MJ/m ² .

The heat release rate (HRR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 2 in FIG. 1 .

The total heat release (THR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 2 in FIG. 2 .

The total smoke release (TSP)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 2 in FIG. 3 .

The preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is compared with the preparation method described in Embodiment 14, except that the silane weighed in step 2 Except that the modified ammonium polyphosphate is changed to 20g, all the other steps and parameters are the same.

Specific embodiment sixteen: present embodiment is the wood flour/polypropylene wood-plastic composite material of fire retardant with silane modified ammonium polyphosphate, it is by 60g wood flour, 40g polypropylene, 25g silane modified ammonium polyphosphate ( M-APP), 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010, the silane The modified ammonium polyphosphate is made from 100 g of ammonium polyphosphate and 1.5 g of γ-methacryloxypropyltrimethoxysilane.

The preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is compared with the preparation method described in Embodiment 14, except that the silane weighed in step 2 Except that the modified ammonium polyphosphate is changed to 25g, all the other steps and parameters are the same.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, tensile strength is 28.04MPa, bending strength is 65.53MPa, impact strength is 5.75kJ/m ² ; heat resistance is good, the temperature (T _1wt% ) when the weight loss is 1% is 102.3℃, the highest decomposition peak The temperature value (T _max1 ) is 322.9°C, the highest peak temperature value (T _max2 ) of polypropylene decomposition is 519.6°C, and the residual carbon mass at 800°C is 22.7%; the flame retardancy is good, the limiting oxygen index is 30.7%, and the ignition time (TTI) up to 56s, the heat release rate (HRR) is small at 154.9kW/m ² , and the total heat release (THR) is small at 57.2MJ/m ² .

The heat release rate (HRR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 3 in FIG. 1 .

From the curves in Fig. 1, it can be seen that in Embodiments 14 to 16, as the amount of M-APP increases, the heat release rate (HRR) decreases significantly, from 169.7kW/m ² to 154.9kW/m ² . When the amount of M-APP is 20 phr, the wood-plastic composite material shows a good flame retardant effect, and the reduction of HRR becomes smaller if the amount of M-APP is continued to increase.

The total heat release (THR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 3 in FIG. 2 .

Integrating the curves in Fig. 2, it can be seen that in the fourteenth to sixteenth specific embodiments, with the increase of the amount of M-APP, the total heat release (THR) is significantly smaller, and when the amount of M-APP is 25 parts, the total heat release The reduction is not obvious.

The total smoke emission (TSP)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 3 in FIG. 3 .

From the curves in Fig. 3, it can be seen that in the fourteenth to sixteenth specific embodiments, with the increase of the amount of M-APP, the total smoke release (TSP) obviously decreases, and when the amount of M-APP is 25 parts, the total heat release The reduction is not obvious.

Simultaneously, the thermogravimetric curve (TG curve) and the derivative thermogravimetric curve ( DTG curve) are shown in curve 1 in Fig. 4 and curve 1 in Fig. 5 respectively.

The scanning electron micrograph of the carbon layer on the surface of the wood-plastic composite material of this embodiment after the flame retardant performance test is carried out according to the ASTM 1356-90 standard by using a cone calorimeter is shown in FIG. 9 . It can be seen from Figure 9 that the charcoal layer on the combustion surface of the composite material added with M-APP is more bulky, and the thicker charcoal layer produces a thicker protective film on the surface of the material to prevent the spread of the fire. It can be seen that KH-570 can improve APP in the composite The dispersion and combination in the material can promote the charcoal formation of wood powder, prevent heat transfer to polypropylene (PP) and prevent oxygen from entering the material to support combustion. The charcoal layer structure is the primary factor for flame retardancy, combined with the conical The thermal instrument data analysis and the improvement of mechanical properties indicate that M-APP not only improves the mechanical properties of materials in wood-plastic composites, but also improves the flame retardancy.

Specific Embodiment Seventeen: This embodiment is comparative example one: ammonium polyphosphate is the wood flour/polypropylene wood-plastic composite material of flame retardant, and it is made of 60g wood flour, 40g polypropylene, 25g ammonium polyphosphate (APP) , 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010.

The preparation method is: 1. Weigh the following raw materials by weight: 60g wood flour, 40g polypropylene, 25g ammonium polyphosphate, 6gm-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1g antioxidant 1010; 2. Mix and stir the raw materials weighed in step 1 to obtain a mixture, then input the mixture into a feeder with metering, adjust the feeding speed to 5r·min ^-1 , and then send Into the twin-screw extruder, set the temperature of each section of the twin-screw extruder from the feeding port to the head of the machine to be 160°C, 170°C, 170°C, 180°C, 180°C, 175°C, 165°C, 160°C, the screw speed is 40r·min ^-1 , the length-to-diameter ratio of the twin-screw extruder is 35:1, after the mixture is extruded by the twin-screw extruder, it is cooled to obtain wood with ammonium polyphosphate as a flame retardant Powder/polypropylene wood plastic composite.

In this embodiment, ammonium polyphosphate without silane modification is used as the flame retardant, and the mechanical performance parameters are: the tensile strength is 21.88MPa, the bending strength is 59.87MPa, and the impact strength is 3.39kJ/m ² ; the heat resistance performance parameters are : The temperature (T _1wt% ) at 1% weight loss is 110.7°C, the highest decomposition temperature (T _max1 ) is 329.2°C, the highest decomposition temperature of polypropylene (T _max2 ) is 518.0°C, and the residue at 800°C The carbon mass is 21.5%; the flame retardant performance parameters are: the limiting oxygen index is 27.4%, the ignition time (TTI) is 28s, the heat release rate (HRR) is small, 196.2kW/m ² , and the total heat release (THR) value Small, 72MJ/m ² .

The thermogravimetric curve (TG curve) and the derivative thermogravimetric curve (DTG curve) of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant of the present embodiment obtained by using a thermogravimetric analyzer test are respectively as follows Curve 2 in Figure 4 and Curve 2 in Figure 5. In Fig. 5, curve 2 and the curve after 400°C corresponding to curve 1 almost coincide.

The heat release rate (HRR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate (APP) as a flame retardant in this embodiment is shown in curve 1 in FIG. 6 .

The total heat release (THR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 1 in FIG. 7 .

The total smoke emission (TSP)-time (s) curve of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant in this embodiment is shown in curve 1 in FIG. 8 .

The scanning electron micrograph of the carbon layer on the surface of the wood-plastic composite material of this embodiment after the flame retardant performance test according to the ASTM 1356-90 standard is shown in FIG. 10 using a cone calorimeter. It can be seen from Figure 10 that the surface carbon layer is thin and dense.

Embodiment 18: This embodiment is Comparative Example 2: wood powder/polypropylene wood-plastic composite material without flame retardant, which consists of 60g wood powder, 40g polypropylene, 6gm-isopropenyl-α, α - Made of dimethyl benzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010.

The preparation method is: 1. Take the following raw materials by weight: 60g wood flour, 40g polypropylene, 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1g antioxidant 1010; 2. Mix and stir the raw materials weighed in step 1 to obtain a mixture, then feed the mixture into a feeder with metering, adjust the feeding speed to 5r·min ^-1 , and then send it into the twin-screw extruder In the extruder, set the screw temperature of each section of the twin-screw extruder from the feed port to the machine head to be 160°C, 170°C, 170°C, 180°C, 180°C, 175°C, 165°C, 160°C, and the screw The rotation speed is 40r·min ^-1 , the length-to-diameter ratio of the twin-screw extruder is 35:1, and the compound is extruded by the twin-screw extruder and cooled to obtain the wood powder/polypropylene wood-plastic composite material.

The wood powder/polypropylene wood-plastic composite material prepared without flame retardant in this embodiment has mechanical performance parameters: tensile strength is 23.27MPa, bending strength is 60.29MPa, impact strength is 3.94kJ/m ² ; heat resistance The performance parameters are: the temperature at 1% weight loss (T _1wt% ) is 118.4°C, the highest decomposition peak temperature (T _max1 ) is 383.2°C, the highest polypropylene decomposition peak temperature (T _max2 ) is 444.8°C, 800°C The mass of residual charcoal was 12.6%; the flame retardant performance parameters were: the limiting oxygen index was 23.6%, the ignition time (TTI) was 33s, the heat release rate (HRR) was 357.5kW/m ² , the total heat release ( THR) has a large value, 102.1MJ/m ² .

The thermogravimetric curve (TG curve) and the derivative thermogravimetric curve (DTG curve) of the wood flour/polypropylene wood-plastic composite material without adding flame retardants of the present embodiment obtained by the thermogravimetric analyzer test are shown in Fig. 4 respectively Curve 3 and curve 3 in Figure 5.

It can be seen from Figure 4 that the thermal degradation process in the TG curve experiences two platforms, the first inflection point is when wood flour begins to decompose, and the second inflection point is when polypropylene begins to decompose. It can be seen from Figure 5 that after adding APP and M-APP, the maximum decomposition temperature of wood powder moves to low temperature, while the maximum decomposition temperature of polypropylene moves to high temperature. The analysis shows that the initial decomposition time of wood-plastic composites is shortened after adding APP or M-APP, which promotes the charring of composite materials; compared with adding APP, adding M-APP can reduce T _1wt% from 110.7 to 102.3 ℃, T _max1 Decreased from 329.3 to 322.9°C, T _max2 increased from 518.0 to 519.6°C, and carbon residue increased from 21.5 to 22.7% at 800°C.

The heat release rate (HRR)-time (s) curve of the wood powder/polypropylene wood-plastic composite material without adding a flame retardant in this embodiment is shown in curve 2 in FIG. 6 .

The total heat release (THR)-time (s) curve of the wood flour/polypropylene wood-plastic composite material without adding a flame retardant in this embodiment is shown in curve 2 in FIG. 7 .

The total smoke delivery (TSP)-time (s) curve of the wood powder/polypropylene wood-plastic composite material without adding a flame retardant in this embodiment is shown in curve 2 in FIG. 8 .

For convenience of comparison, the total heat release (THR)-time (s) curve, total heat release The amount (THR)-time (s) curve and the total smoke delivery (TSP)-time (s) curve are correspondingly recorded in Fig. 6, Fig. 7 and Fig. 8 respectively, and are marked as curve 3.

Comprehensive analysis and comparison of specific embodiments 16, 17 and 18 can be obtained, and the mechanical properties of the wood powder/polypropylene wood-plastic composite material using ammonium polyphosphate as a flame retardant in the 17th embodiment are compared with the 18th embodiment The mechanical properties of wood powder/polypropylene wood-plastic composite materials are poor, indicating that the addition of highly polar polymer ammonium polyphosphate has poor dispersion and bonding in wood-plastic composite materials, so after adding APP, wood powder/polypropylene On the contrary, the mechanical properties of polypropylene wood-plastic composites decrease. Using ammonium polyphosphate modified by γ-methacryloxypropyl trimethoxysilane as the flame retardant wood flour/polypropylene wood-plastic composite material than the wood flour/polypropylene wood-plastic composite material of specific embodiment eighteen The mechanical properties of propylene wood-plastic composites have been improved, indicating that the dispersibility and bonding of ammonium polyphosphate modified by silane in wood flour/polypropylene wood-plastic composites have become better, and the compatibility has become better, making wood flour / The mechanical properties of polypropylene wood-plastic composites are greatly improved.

At the same time, the heat resistance and flame retardancy of the wood-plastic composite material in Embodiment 16 are both improved and better than those of the wood-plastic composite material in Embodiment 17.

Specific embodiment nineteen: present embodiment is the wood flour/polypropylene wood-plastic composite material that uses silane-modified ammonium polyphosphate as flame retardant, and it is made of 60g wood flour, 40g polypropylene, 25g silane-modified ammonium polyphosphate ( M-APP), 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010, the silane The modified ammonium polyphosphate is made from 100g of ammonium polyphosphate and 0.5g of γ-methacryloxypropyltrimethoxysilane.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, the tensile strength is 24.93MPa, the bending strength is 61.98MPa, and the impact strength is 4.33kJ/m ² .

The preparation method of the wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as flame retardant in this embodiment is realized through the following steps: 1. Mix 100g ammonium polyphosphate, 0.5g gamma- Put methacryloxypropyltrimethoxysilane and 150mL absolute ethanol into a three-necked flask, stir at 60°C for 1 hour, then filter with suction, then put the filter cake in an oven and dry it at 105°C 3h to obtain silane-modified ammonium polyphosphate (M-APP); 2. Take the following raw materials in parts by weight: 60g wood flour, 40g polypropylene, 25g silane-modified ammonium polyphosphate prepared in step 1, 6g m-isopropylene Base-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1g antioxidant 1010; 3. Mix and stir the raw materials weighed in step 2 to obtain a mixture, and then input the mixture into the metering In the feeder, adjust the feeding speed to 5r·min ^-1 , and then feed it into the twin-screw extruder, and set the screw temperature of each section of the twin-screw extruder from the feeding port to the machine head to be 160°C ^. After being extruded by the extruder, the wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as the flame retardant can be obtained after cooling.

Specific Embodiment Twenty: This embodiment is a wood flour/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant, which consists of 60g wood flour, 40g polypropylene, and 25g silane-modified ammonium polyphosphate ( M-APP), 6gm-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010, the silane modified The permanent ammonium polyphosphate is made from 100g of ammonium polyphosphate and 1.0g of γ-methacryloxypropyltrimethoxysilane.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, the tensile strength is 25.35MPa, the bending strength is 63.03MPa, and the impact strength is 4.45kJ/m ² .

Compared with the preparation method described in the nineteenth specific embodiment, the preparation method of the wood flour/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment, except for the γ-methyl Except the amount of acryloyloxypropyl trimethoxysilane is different, the other steps and parameters are the same.

Specific Embodiment Twenty-one: This embodiment is a wood flour/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant, which consists of 60g wood flour, 40g polypropylene, and 25g silane-modified ammonium polyphosphate (M-APP), 6gm-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010, the silane The modified ammonium polyphosphate is made from 100 g of ammonium polyphosphate and 2.0 g of γ-methacryloxypropyltrimethoxysilane.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, the tensile strength is 25.20MPa, the bending strength is 62.02MPa, and the impact strength is 4.11kJ/m ² .

Compared with the preparation method described in the nineteenth specific embodiment, the preparation method of the wood flour/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment, except for the γ-methyl Except the amount of acryloyloxypropyl trimethoxysilane is different, the other steps and parameters are the same.

Specific Embodiment Twenty-two: This embodiment is a wood flour/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as a flame retardant, which consists of 60g wood flour, 40g polypropylene, and 30g silane-modified ammonium polyphosphate (M-APP), 6g m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) coupling agent and 1g antioxidant 1010 are made, the described The silane-modified ammonium polyphosphate is made from 100 g of ammonium polyphosphate and 1.5 g of γ-methacryloxypropyltrimethoxysilane.

The wood powder/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment has the advantages of good flame retardancy, high mechanical performance, and good heat resistance. Good mechanical properties, the tensile strength is 26.31MPa, the bending strength is 62.46MPa, and the impact strength is 4.88kJ/m ² .

The preparation method of the wood flour/polypropylene wood-plastic composite material using silane-modified ammonium polyphosphate as a flame retardant in this embodiment is compared with the preparation method described in Embodiment 14, except that the silane weighed in step 2 Except that the modified ammonium polyphosphate is changed to 20g, all the other steps and parameters are the same.

Among them, the data of the mechanical properties of the wood-plastic composite materials involved in the present invention are all obtained by the following test methods: use a universal mechanical testing machine to measure the tensile strength and bending strength of the wood-plastic composite materials, use a cantilever impact testing machine Determination of impact strength of composite materials. The average value of each sample balance test is 5 times. The tensile strength test is based on the ASTMD638 standard, and the tensile speed is 5mm/min; the bending strength test is based on the ASTM D790 standard, the test speed is 2mm/min, and the span is 64mm; the impact strength test is based on ASTM D256 standard.

The heat resistance data of the wood-plastic composite materials involved in the present invention are all obtained by the following test method: use the Perkin-Elmer Pyris 1 thermogravimetric analysis instrument to analyze the thermal degradation behavior of the sample, and the experiment is carried out in a pure nitrogen environment , from 30 to 800°C at a heating rate of 10°C·min ^-1 , and the weight of each sample is about 3-5mg.

The flame retardancy data of the wood-plastic composite materials involved in the present invention are all obtained by the following test method: the cone calorimeter test is based on the ASTM 1356-90 standard, and the sample size is 100×100×3mm plate, using FTTStandard Cone calorimeter is used for testing, and the heat radiation flow rate adopted is 50kW/m ² .

Claims (10)

1. A wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as flame retardant, characterized in that the wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as flame retardant In parts by weight, it is composed of 50-70 parts of wood flour, 30-50 parts of polypropylene, 15-30 parts of silane-modified ammonium polyphosphate, and 3-6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate. Branched polypropylene coupling agent and 0.1-1 part of antioxidant, the silane-modified ammonium polyphosphate is composed of 80-100 parts of ammonium polyphosphate and 0.5-2 parts of γ-methacryloyloxy Propyltrimethoxysilane. 2. A kind of wood powder/polypropylene wood-plastic composite material taking silane-modified ammonium polyphosphate as fire retardant according to claim 1, it is characterized in that the wood powder taking silane-modified ammonium polyphosphate as fire retardant / Polypropylene wood-plastic composite material is grafted by weight by 60 parts of wood flour, 40 parts of polypropylene, 20 parts of silane-modified ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate Made of polypropylene coupling agent and 1 part antioxidant. 3. A kind of wood powder/polypropylene wood-plastic composite material taking silane-modified ammonium polyphosphate as fire retardant according to claim 1, it is characterized in that the wood powder taking silane-modified ammonium polyphosphate as fire retardant / Polypropylene wood-plastic composite material is grafted by weight by 60 parts of wood flour, 40 parts of polypropylene, 25 parts of silane-modified ammonium polyphosphate, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate Made of polypropylene coupling agent and 1 part antioxidant. 4. according to claim 1,2 or 3, a kind of wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as flame retardant, is characterized in that described silane-modified ammonium polyphosphate is by weight One part is made of 90-100 parts of ammonium polyphosphate and 1-2 parts of γ-methacryloxypropyl trimethoxysilane. 5. according to claim 1,2 or 3 described a kind of wood flour/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as flame retardant, it is characterized in that described silane-modified ammonium polyphosphate is by weight Parts are made from 100 parts ammonium polyphosphate and 1.5 parts gamma-methacryloxypropyltrimethoxysilane. 6. as claimed in claim 1 with silane modified ammonium polyphosphate as the preparation method of wood powder/polypropylene wood-plastic composite material of flame retardant, it is characterized in that the wood powder with silane modified ammonium polyphosphate as flame retardant The preparation method of the powder/polypropylene wood-plastic composite material is realized through the following steps: 1. Mix 80 to 100 parts of ammonium polyphosphate, 0.5 to 2 parts of γ-methacryloxypropyltrimethoxysilane in parts by weight and absolute ethanol in a three-necked flask, stirred at 60°C for 1 hour, then suction filtered, then put the filter cake in an oven, and dried at 105°C for 3 hours to obtain silane-modified ammonium polyphosphate, of which The ratio of ammonium weight to absolute ethanol volume is 80-100g: 150mL; 2. Weigh the following raw materials by weight: 50-70 parts of wood flour, 30-50 parts of polypropylene, 15-30 parts of silane modified Ammonium polyphosphate, 3 to 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 0.1 to 1 part of antioxidant; 3. The raw materials weighed in step 2 Mix and stir evenly to obtain the compound, then input the compound into the feeder with metering, adjust the feeding speed to 5r·min ^-1 , and then send it into the twin-screw extruder, set each of the twin-screw extruder The temperature of the section screw from the feeding port to the machine head is 160°C, 170°C, 170°C, 180°C, 180°C, 175°C, 165°C, 160°C, the screw speed is 40r·min ^-1 , the twin-screw extrusion The aspect ratio of the extruder is 35:1. After the mixture is extruded by the twin-screw extruder, it is cooled to obtain the wood powder/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as the flame retardant. 7. the preparation method of wood flour/polypropylene wood-plastic composite material with silane-modified ammonium polyphosphate as fire retardant according to claim 6, it is characterized in that in step 1, 90～100 parts of polyphosphoric acid are added by weight Ammonium, 1 to 2 parts of γ-methacryloxypropyltrimethoxysilane and absolute ethanol are put into a three-necked bottle. 8. the preparation method of the wood powder/polypropylene wood-plastic composite material taking silane-modified ammonium polyphosphate as flame retardant according to claim 6 is characterized in that in step 1, 100 parts of ammonium polyphosphate, ammonium polyphosphate, Put 1.5 parts of γ-methacryloxypropyltrimethoxysilane and absolute ethanol into a three-neck bottle. 9. according to the preparation method of the wood flour/polypropylene wood-plastic composite material of fire retardant with silane modified ammonium polyphosphate according to claim 6, 7 or 8, it is characterized in that in step 2, take by weight as follows Raw materials: 60 parts of wood flour, 40 parts of polypropylene, 20 parts of silane-modified ammonium polyphosphate prepared in step 1, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part antioxidant. 10. according to the preparation method of the wood flour/polypropylene wood-plastic composite material of fire retardant with silane-modified ammonium polyphosphate according to claim 6, 7 or 8, it is characterized in that in step 2, take by weight as follows Raw materials: 60 parts of wood flour, 40 parts of polypropylene, 25 parts of silane-modified ammonium polyphosphate prepared in step 1, 6 parts of m-isopropenyl-α, α-dimethylbenzyl isocyanate grafted polypropylene coupling agent and 1 part antioxidant.

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