Plastic-wood plate without cracking under low-temperature freezing condition and manufacturing method of plastic-wood plate

Abstract

The invention relates to a composite material plate, in particular to a plastic-wood plate without cracking under a low-temperature freezing condition and a preparation method of the plastic-wood plate, and belongs to the technical field of ecological environment materials and composite materials. The invention relates to a plastic-wood plate without cracking under a low-temperature freezing condition. The plastic-wood plate is formed by compounding low-temperature-resistant plastic particles, joint modified wood flour, a methyl methacrylate / butadiene / styrene terpolymer, laurinol, long-chain fatty acid ester and an antioxidant. According to the invention, the low-temperature-resistant plastic matrix, the polydopamine layer and the aminated inorganic particles are combined to modify the wood flour and the combined long-chain plasticizing system, so that the obtained plastic-wood plate has good mechanical property and excellent low-temperature freezing resistance.

Description

Technical Field

[0001] The present invention relates to a composite material board, in particular to a plastic wood board that does not crack under low-temperature freezing conditions and a preparation method thereof, belonging to the technical field of ecological environment materials and composite materials. Background Art

[0002] Wood-plastic composites (WPCs) are a new chemical material that has developed rapidly in recent years. They offer advantages such as corrosion resistance, moisture resistance, insect resistance, high dimensional stability, and the absence of toxic components. They are widely used in outdoor flooring, pool edging, flower boxes, tree pits, fences, trash cans, sunshades, benches, chair rails, backrests, leisure tabletops, signboards, bulletin boards, beams, dock decking, waterways, handrails, guardrails, fences, partitions, flower trellises and corridors, outdoor pavilions, open-air terraces, bathroom panels, door and window frames, sound-absorbing panels, and roof panels. At the same time, the application area of ​​WPCs is also continuously expanding. Traditional WPCs are mostly used in relatively warm climates. When used in long-term low-temperature freezing conditions, especially in extreme freezing conditions, due to the different physical properties of the WPC components, the panels may crack, affecting their normal use.

[0003] Therefore, it is very necessary to invent a plastic wood board that does not crack under low-temperature freezing conditions, overcome the shortcomings of conventional plastic wood composite materials, can be used in low-temperature freezing environments, especially in extreme low-temperature freezing environments, and further expand the scope of use of plastic wood materials. Summary of the Invention

[0004] The present invention is aimed at the above purpose and provides a plastic wood board that does not crack under low temperature freezing conditions and a method for making the same.

[0005] A plastic wood board that does not crack under low-temperature freezing conditions is composited from low-temperature resistant plastic particles, jointly modified wood flour, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, long-chain fatty acid ester and antioxidant.

[0006] The low-temperature resistant plastic particles are made from high-density polyethylene, linear low-density polyethylene and polyolefin elastomer grafts through melting reaction.

[0007] The jointly modified wood powder is prepared by jointly modifying wood powder with dopamine and amination inorganic particles.

[0008] The long-chain fatty acid ester is one of ethyl myristate, ethyl hexadecanoate and palmitate.

[0009] The antioxidant is one of antioxidant 1010 and antioxidant 168.

[0010] A plastic wood board that does not crack under low-temperature freezing conditions, the production method of which comprises the following steps:

[0011] (1) soaking wood powder in a 10-20 wt% sodium hydroxide solution for 10-20 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel according to 100-120% of the mass of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 30-60 minutes, heating to 60-70° C. and continuing to react for 2-4 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0012] (2) lithium fluoride and titanium aluminum carbide are weighed in a mass ratio of 100:100-120, and lithium fluoride is completely dispersed in a 30-40 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide is added and ultrasonically dispersed. The solution temperature is then raised to 35-45°C, stirred for 24-36 hours, filtered, and the filtered solid is washed with distilled water until the pH value of the washing solution is greater than 6. The solid is then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passes through the sieve is retained and prepared into a 2-4 wt% inorganic aqueous solution;

[0013] (3) respectively measuring the inorganic aqueous solution obtained in step (2), anhydrous ethanol and 3-aminopropyltriethoxysilane in a volume ratio of 1:10-16:0.03-0.07, mixing the inorganic aqueous solution obtained in step (2) with anhydrous ethanol, adjusting the pH of the mixture to 3-5, then slowly adding 3-aminopropyltriethoxysilane, and ultrasonically reacting at 60-70° C. for 3-7 hours. After the reaction is completed, cooling to room temperature to obtain an amination inorganic particle solution;

[0014] (4) soaking the primary modified wood powder obtained in step (1) in a 0.1-0.3 wt% dopamine hydrochloride solution, ultrasonically dispersing for 40-60 minutes, then adjusting the pH of the solution to 8-9, adding a 0.04-0.08 wt% potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 2-6 hours to obtain a dopamine-modified wood powder solution;

[0015] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) are measured in a volume ratio of 100:4-10, mixed evenly, and subjected to ultrasonic treatment for 40-60 minutes, filtered, and the filtered wood powder is rinsed with tap water until the elution is neutral, and then the rinsed wood powder is dried to obtain a combined modified wood powder;

[0016] (6) Weighing a polyolefin elastomer, maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.5-0.9:0.05-0.07, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing the mixture with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0017] (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:6-12:1-5, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0018] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, long-chain fatty acid ester and antioxidant were weighed respectively according to the mass ratio of 100:260-300:3-7:0.6-1.2:0.8-1.6:0.8-1.6, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0019] The polyolefin elastomer is one of ethylene-propylene rubber and styrene-butadiene-styrene block copolymer rubber.

[0020] The long-chain fatty acid ester is one of ethyl myristate, ethyl hexadecanoate and palmitate.

[0021] The antioxidant is one of antioxidant 1010 and antioxidant 168.

[0022] Compared with traditional plastic wood panels, the present invention has original features in terms of surface treatment of the plastic matrix, wood powder, and interface modification between the two. Specifically:

[0023] (1) Traditional high-density polyethylene-based plastic wood panels have good mechanical strength, rigidity and heat resistance, but high-density polyethylene has a highly linear structure, high crystallinity and a relatively high brittle temperature. The plastic wood panels produced may become brittle and crack when used for a long time in an extreme low-temperature environment. The present invention uses linear low-density polyethylene with a lower brittle temperature to blend with high-density polyethylene to form a blended plastic matrix. At the same time, a compatibilizer is used to form molecular chain entanglement and co-crystallization at the interface of high-density polyethylene and linear low-density polyethylene, thereby improving the adhesion between the two plastics, thereby effectively preventing the matrix cracking that may occur when the plastic wood panels are used for a long time in an extreme low-temperature environment.

[0024] (2) To improve the low-temperature resistance of wood-plastic composite materials, the surface treatment of wood powder is very important. The present invention first performs carboxylation treatment on the surface of wood powder, and then self-polymerizes a polydopamine layer and amino inorganic particles on the surface of wood powder. The amino inorganic particles and the carboxyl wood powder surface form a strong bond through an amidation reaction. After the combined modification, not only the adhesion function of the wood powder surface to the plastic matrix in the composite material is significantly enhanced, but also the free energy and roughness of the fiber surface are enhanced, which is beneficial to the penetration between the fiber and the plastic matrix, thereby improving the interface bonding strength.

[0025] (3) The plasticizers commonly used in traditional plastic wood boards are phthalates, which will partially lose their function under extremely low temperature conditions and cause the boards to crack. The present invention uses methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol and long-chain fatty acid esters for combined plasticization, which is better adapted to long-term use in extremely low temperature environments. DETAILED DESCRIPTION

[0026] A plastic wood board that does not crack under low-temperature freezing conditions is composited from low-temperature resistant plastic particles, jointly modified wood flour, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, long-chain fatty acid ester and antioxidant.

[0027] The low-temperature resistant plastic particles are made from high-density polyethylene, linear low-density polyethylene and polyolefin elastomer grafts through melting reaction.

[0028] The jointly modified wood powder is prepared by jointly modifying wood powder with dopamine and amination inorganic particles.

[0029] The long-chain fatty acid ester is one of ethyl myristate, ethyl hexadecanoate and palmitate.

[0030] The antioxidant is one of antioxidant 1010 and antioxidant 168.

[0031] Example 1: A plastic wood board that does not crack under low-temperature freezing conditions, the manufacturing method of which comprises the following steps:

[0032] (1) soaking wood powder in a 15 wt% sodium hydroxide solution for 15 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel according to 110% of the mass of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 45 minutes, heating to 65° C. and continuing to react for 3 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0033] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:110, and lithium fluoride was completely dispersed in a 35 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 40°C, stirred for 30 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the washing solution was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 3 wt% inorganic aqueous solution.

[0034] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:13:0.05, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol, the pH of the mixture was adjusted to 4, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 65° C. for 5 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0035] (4) soaking the primary modified wood powder obtained in step (1) in a 0.2 wt % dopamine hydrochloride solution, ultrasonically dispersing for 50 minutes, then adjusting the pH of the solution to 8.5, adding a 0.06 wt % potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 4 hours to obtain a dopamine-modified wood powder solution;

[0036] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:7, mixed evenly, and subjected to ultrasonic treatment for 50 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0037] (6) Weighing a polyolefin elastomer (ethylene-propylene rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.7:0.06, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0038] (7) weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:9:3, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0039] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, ethyl hexadecanoate and antioxidant 1010 were weighed respectively in a mass ratio of 100:280:5:0.9:1.2:1.2, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0040] Example 2: A plastic wood board that does not crack under low-temperature freezing conditions, the manufacturing method of which comprises the following steps:

[0041] (1) soaking wood powder in a 10 wt% sodium hydroxide solution for 10 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel according to 100% of the mass of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 30 minutes, heating to 60° C. and continuing to react for 2 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0042] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:100, and lithium fluoride was completely dispersed in a 30 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 35°C, stirred for 24 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the washing solution was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 2 wt% inorganic aqueous solution.

[0043] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:10:0.03, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol, the pH of the mixture was adjusted to 3, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 60° C. for 3 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0044] (4) soaking the primary modified wood powder obtained in step (1) in a 0.1 wt% dopamine hydrochloride solution, ultrasonically dispersing for 40 minutes, then adjusting the solution pH to 8, adding a 0.04 wt% potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 2 hours to obtain a dopamine-modified wood powder solution;

[0045] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:4, mixed evenly, and subjected to ultrasonic treatment for 40 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0046] (6) Polyolefin elastomer (ethylene-propylene rubber), maleic anhydride, and dicumyl peroxide were weighed in a mass ratio of 100:0.5:0.05, maleic anhydride and dicumyl peroxide were dissolved in acetone, and then mixed with the polyolefin elastomer. After drying, the mixture was melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product;

[0047] (7) High-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) are weighed respectively in a mass ratio of 100:6:1, mixed evenly, and then melt-reacted and extruded through a twin-screw extruder to form pellets to obtain low-temperature resistant plastic particles;

[0048] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, ethyl tetradecanoate and antioxidant 1010 were weighed respectively in a mass ratio of 100:260:3:0.6:0.8:0.8, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0049] Example 3: A method for producing a wood-plastic board that does not crack under low-temperature freezing conditions comprises the following steps:

[0050] (1) soaking wood powder in a 20 wt% sodium hydroxide solution for 20 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel according to 120% of the mass of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 60 minutes, heating to 70° C. and continuing to react for 4 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0051] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:120, and lithium fluoride was completely dispersed in a 40 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 45°C, stirred for 36 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the eluate was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 4 wt% inorganic aqueous solution.

[0052] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:16:0.07, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol, the pH of the mixture was adjusted to 5, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 70° C. for 7 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0053] (4) soaking the primary modified wood powder obtained in step (1) in a 0.3 wt % dopamine hydrochloride solution, ultrasonically dispersing for 60 minutes, then adjusting the solution pH to 9, adding a 0.08 wt % potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 6 hours to obtain a dopamine-modified wood powder solution;

[0054] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:10, mixed evenly, and subjected to ultrasonic treatment for 60 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0055] (6) Weighing a polyolefin elastomer (styrene-butadiene-styrene block copolymer rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.9:0.07, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0056] (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:12:5, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0057] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, palmitic acid ester and antioxidant 168 were weighed respectively in a mass ratio of 100:300:7:1.2:1.6:1.6, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0058] Example 4: A method for producing a wood-plastic board that does not crack under low-temperature freezing conditions comprises the following steps:

[0059] (1) soaking wood powder in a 10 wt% sodium hydroxide solution for 15 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol; then adding monochloroacetic acid to the reaction vessel in an amount of 120% by weight of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 30 minutes, heating to 65° C., and continuing to react for 4 hours; removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0060] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:100, and lithium fluoride was completely dispersed in a 35 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 45°C, stirred for 24 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the washing solution was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 3 wt% inorganic aqueous solution.

[0061] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:16:0.03, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol, the pH of the mixture was adjusted to 4, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 70° C. for 3 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0062] (4) soaking the primary modified wood powder obtained in step (1) in a 0.2 wt% dopamine hydrochloride solution, ultrasonically dispersing for 60 minutes, then adjusting the solution pH to 8, adding a 0.06 wt% potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 6 hours to obtain a dopamine-modified wood powder solution;

[0063] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:4, mixed evenly, and subjected to ultrasonic treatment for 50 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0064] (6) Weighing a polyolefin elastomer (styrene-butadiene-styrene block copolymer rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.9:0.05, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0065] (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:12:1, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0066] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, ethyl tetradecanoate and antioxidant 168 were weighed respectively in a mass ratio of 100:280:7:0.6:1.2:1.6, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0067] Example 5: A method for producing a wood-plastic board that does not crack under low-temperature freezing conditions comprises the following steps:

[0068] (1) soaking wood powder in a 15 wt% sodium hydroxide solution for 20 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol; then adding monochloroacetic acid to the reaction vessel in an amount of 100% by weight of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 45 minutes, heating to 70° C., and continuing to react for 2 hours; removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0069] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:110, and lithium fluoride was completely dispersed in a 40 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 35°C, stirred for 30 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the washing solution was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 4 wt% inorganic aqueous solution.

[0070] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:10:0.05, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol in advance, the pH of the mixture was adjusted to 5, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 60° C. for 5 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0071] (4) Soaking the primary modified wood powder obtained in step (1) in a 0.3 wt % dopamine hydrochloride solution, ultrasonically dispersing for 40 minutes, then adjusting the solution pH to 8.5, adding a 0.08 wt % potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 2 hours to obtain a dopamine-modified wood powder solution;

[0072] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:7, mixed evenly, and subjected to ultrasonic treatment for 60 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0073] (6) Weighing a polyolefin elastomer (styrene-butadiene-styrene block copolymer rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.5:0.06, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0074] (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:6:3, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0075] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, ethyl hexadecanoate and antioxidant 168 were weighed respectively in a mass ratio of 100:300:3:0.9:1.6:0.8, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0076] Example 6: A plastic wood board that does not crack under low-temperature freezing conditions, the manufacturing method of which comprises the following steps:

[0077] (1) soaking wood powder in a 20 wt% sodium hydroxide solution for 10 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel in an amount of 110% by weight of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 60 minutes, heating to 60° C., and continuing to react for 3 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0078] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:120, and lithium fluoride was completely dispersed in a 30 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 40°C, stirred for 36 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the washing solution was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 2 wt% inorganic aqueous solution.

[0079] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:13:0.07, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol, the pH of the mixture was adjusted to 3, and then 3-aminopropyltriethoxysilane was slowly added. The mixture was ultrasonically reacted at 65° C. for 7 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0080] (4) soaking the primary modified wood powder obtained in step (1) in a 0.1 wt% dopamine hydrochloride solution, ultrasonically dispersing for 50 minutes, then adjusting the solution pH to 9, adding a 0.04 wt% potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 4 hours to obtain a dopamine-modified wood powder solution;

[0081] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:10, mixed evenly, and subjected to ultrasonic treatment for 40 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0082] (6) Weighing a polyolefin elastomer (ethylene-propylene rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.7:0.07, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0083] (7) weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:9:5, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0084] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, palmitic acid ester and antioxidant 1010 were weighed respectively in a mass ratio of 100:260:5:1.2:0.8:1.2, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0085] Example 7: A plastic wood board that does not crack under low-temperature freezing conditions, the manufacturing method of which comprises the following steps:

[0086] (1) soaking wood powder in a 12 wt% sodium hydroxide solution for 12 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel in an amount of 105% by weight of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 50 minutes, heating to 68° C., and continuing to react for 2.4 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder;

[0087] (2) lithium fluoride and titanium aluminum carbide were weighed in a mass ratio of 100:106, and lithium fluoride was completely dispersed in a 36 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide was added and ultrasonically dispersed. The solution temperature was then raised to 36°C, stirred for 28 hours, filtered, and the filtered solid was washed with distilled water until the pH value of the eluate was greater than 6. The solid was then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passed through the sieve was retained and prepared into a 2.4 wt% inorganic aqueous solution.

[0088] (3) The inorganic aqueous solution obtained in step (2), anhydrous ethanol, and 3-aminopropyltriethoxysilane were respectively measured in a volume ratio of 1:12:0.06, the inorganic aqueous solution obtained in step (2) was mixed with anhydrous ethanol in advance, the pH of the mixture was adjusted to 3.5, and then 3-aminopropyltriethoxysilane was slowly added, and ultrasonic reaction was carried out at 64° C. for 4 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain an amination inorganic particle solution;

[0089] (4) soaking the primary modified wood powder obtained in step (1) in a 0.13 wt % dopamine hydrochloride solution, ultrasonically dispersing for 49 minutes, then adjusting the pH of the solution to 8.9, adding a 0.05 wt % potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 3 hours to obtain a dopamine-modified wood powder solution;

[0090] (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) were respectively measured in a volume ratio of 100:5, mixed evenly, and subjected to ultrasonic treatment for 48 minutes, filtered, and the filtered wood powder was rinsed with tap water until the elution was neutral, and then the rinsed wood powder was dried to obtain a combined modified wood powder;

[0091] (6) Weighing a polyolefin elastomer (ethylene-propylene rubber), maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.8:0.057, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing them with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product.

[0092] (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:10:4, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles;

[0093] (8) Low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, ethyl hexadecanoate and antioxidant 168 were weighed respectively in a mass ratio of 100:290:6:0.7:1.1:1, mixed evenly, and extruded into plastic wood boards that did not crack under low-temperature freezing conditions using an extruder.

[0094] The effect of Example 1 is demonstrated through experiments below.

[0095] A test plate was prepared according to the method of Example 1 and placed in a freezing environment at -70°C for 30 days.

[0096] After testing, a plastic wood board that does not crack under low-temperature freezing conditions has a static bending strength of 35.96MPa and a static bending modulus of 1.68GPa before freezing; after 30 days of freezing, the static bending strength is 34.68MPa, the static bending modulus is 1.89GPa, and there is no cracking on the surface.

[0097] The test results show that the obtained plastic wood board that does not crack under low-temperature freezing conditions has good mechanical properties and can meet the production needs of daily necessities. At the same time, after being placed in an extreme freezing environment for 30 days, the static bending strength decreased slightly, but not significantly, while the static bending modulus increased significantly, and the sample did not crack, indicating that the board has excellent low-temperature freezing resistance.

Claims

1. The wood plastic board does not crack under low temperature freezing conditions, which is characterized by It is composed of low-temperature resistant plastic particles, jointly modified wood flour, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, long-chain fatty acid ester and antioxidant.

2. The plastic wood board that does not crack under low temperature freezing conditions according to claim 1, characterized in that The low-temperature resistant plastic particles are made from high-density polyethylene, linear low-density polyethylene and polyolefin elastomer grafts through melting reaction.

3. The plastic wood board that does not crack under low temperature freezing conditions according to claim 1, characterized in that The jointly modified wood powder is prepared by jointly modifying wood powder with dopamine and amination inorganic particles.

4. The plastic wood board that does not crack under low temperature freezing conditions according to claim 1, characterized in that The long-chain fatty acid ester is one of ethyl myristate, ethyl hexadecanoate and palmitate.

5. The plastic wood board that does not crack under low temperature freezing conditions according to claim 1, characterized in that The antioxidant is one of antioxidant 1010 and antioxidant 168.

6. The method for producing a wood-plastic board that does not crack under low-temperature freezing conditions according to claim 1, characterized in that The production process includes the following steps: (1) soaking wood powder in a 10-20 wt% sodium hydroxide solution for 10-20 hours, filtering, and drying to obtain alkali-treated wood powder; transferring the alkali-treated wood powder to a reaction vessel and immersing it in industrial alcohol, then adding monochloroacetic acid to the reaction vessel according to 100-120% of the mass of the alkali-treated wood powder, stirring evenly, reacting at room temperature for 30-60 minutes, heating to 60-70° C. and continuing to react for 2-4 hours, removing the wood powder from the container, washing with water until the washing liquid is neutral, and drying to obtain primary modified wood powder; (2) lithium fluoride and titanium aluminum carbide are weighed in a mass ratio of 100:100-120, and lithium fluoride is completely dispersed in a 30-40 wt% hydrofluoric acid solution. After stirring, titanium aluminum carbide is added and ultrasonically dispersed. The solution temperature is then raised to 35-45°C, stirred for 24-36 hours, filtered, and the filtered solid is washed with distilled water until the pH value of the washing solution is greater than 6. The solid is then dried, ground, and sieved with a 200-mesh sample preparation sieve. The sieved material that passes through the sieve is retained and prepared into a 2-4 wt% inorganic aqueous solution; (3) respectively measuring the inorganic aqueous solution obtained in step (2), anhydrous ethanol and 3-aminopropyltriethoxysilane in a volume ratio of 1:10-16:0.03-0.07, mixing the inorganic aqueous solution obtained in step (2) with anhydrous ethanol, adjusting the pH of the mixture to 3-5, then slowly adding 3-aminopropyltriethoxysilane, and ultrasonically reacting at 60-70° C. for 3-7 hours. After the reaction is completed, cooling to room temperature to obtain an amination inorganic particle solution; (4) soaking the primary modified wood powder obtained in step (1) in a 0.1-0.3 wt% dopamine hydrochloride solution, ultrasonically dispersing for 40-60 minutes, then adjusting the solution pH to 8-9, adding 0.04-0.08 wt% potassium ferrate solution according to one tenth of the volume of the dopamine hydrochloride solution, stirring evenly, and continuing ultrasonic dispersion for 2-6 hours to obtain a dopamine-modified wood powder solution; (5) The dopamine-modified wood powder solution obtained in step (4) and the amination-modified inorganic particle solution obtained in step (3) are measured in a volume ratio of 100:4-10, mixed evenly, and subjected to ultrasonic treatment for 40-60 minutes, filtered, and the filtered wood powder is rinsed with tap water until the elution is neutral, and then the rinsed wood powder is dried to obtain a combined modified wood powder; (6) Weighing a polyolefin elastomer, maleic anhydride, and dicumyl peroxide in a mass ratio of 100:0.5-0.9:0.05-0.07, dissolving the maleic anhydride and dicumyl peroxide in acetone, and then mixing the mixture with the polyolefin elastomer. After drying, the mixture is melt-reacted and extruded through a twin-screw extruder, and pelletized to obtain a polyolefin elastomer grafted product. (7) Weighing high-density polyethylene, linear low-density polyethylene, and the polyolefin elastomer graft obtained in step (6) in a mass ratio of 100:6-12:1-5, mixing them uniformly, and then extruding them through a twin-screw extruder through a melt reaction, and granulating them to obtain low-temperature resistant plastic particles; (8) Weighing low-temperature resistant plastic particles, combined modified wood powder, methyl methacrylate / butadiene / styrene terpolymer, lauryl alcohol, long-chain fatty acid ester, and antioxidant according to a mass ratio of 100:260-300:3-7:0.6-1.2:0.8-1.6:0.8-1.6, mixing them evenly, and using an extruder to extrude and form a plastic wood board that does not crack under low-temperature freezing conditions; The polyolefin elastomer is one of ethylene-propylene rubber and styrene-butadiene-styrene block copolymer rubber. The long-chain fatty acid ester is one of ethyl myristate, ethyl hexadecanoate and palmitate. The antioxidant is one of antioxidant 1010 and antioxidant 168.