Composite board as well as preparation method and application thereof

Abstract

The invention discloses a composite board as well as a preparation method and application thereof. The composite board comprises the following components: 50-80 parts of modified vinasse powder and 10-30 parts of an environment-friendly adhesive, wherein the modified vinasse powder is vinasse powder sequentially subjected to damp-heat activation treatment and interface chemical modification treatment. By utilizing the vinasse, the composite board which is completely degradable, free of pollution and excellent in performance is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of artificial board, in particular to a composite board and a preparation method and application thereof. BACKGROUND

[0002] China is a big country in liquor production and consumption, especially in Baijiu production. The distillery industry produces tens of millions of tons of distiller's grains as by-products every year. Distiller's grains are solid residues after grain fermentation and distillation, which are rich in cellulose, hemicellulose, and residual organic matter such as starch and protein. However, its characteristics of high moisture, high acidity, and perishability pose serious challenges to centralized storage, transportation, and large-scale utilization. Improper disposal not only leads to resource waste but also easily causes environmental pollution.

[0003] Currently, the main utilization approaches of distiller's grains are concentrated in low-value-added fields, such as direct use as feed, fertilizer, or biogas raw material. These methods can achieve a certain degree of resource utilization, but they do not fully exploit the potential value of distiller's grains as industrial raw materials. In recent years, researchers have begun to explore the high-value utilization of distiller's grains, such as extracting functional ingredients or preparing bio-based materials, but these methods are often difficult to industrialize due to complex processes, high costs, or insufficient product performance.

[0004] At the same time, in the fields of packaging and architectural decoration, traditional artificial boards (such as particle board and medium-density fiberboard) generally rely on wood raw materials and aldehyde-containing adhesives (such as urea-formaldehyde resin). These boards have the dual environmental problems of forest resource consumption and indoor formaldehyde pollution. With the advancement of the "double carbon" goal and the rise of green consumption, developing biodegradable boards based on renewable resources and non-toxic and harmless has become an urgent need in the industry.

[0005] Therefore, using agricultural waste to prepare environmentally friendly boards has become a research hotspot. For example, Chinese patent document CN115058038A discloses a composite board using plant fibers such as tea residue and coffee residue as raw materials; CN120535970A relates to a technology for preparing large-size boards using coffee residue. These solutions provide useful references for the utilization of waste plant resources, but they do not cover distiller's grains, which have a huge output and unique components. SUMMARY

[0006] Therefore, the present application aims to provide a composite board and a preparation method and application thereof, which aims to solve the problems in the background art and utilize distiller's grains to obtain a completely biodegradable, non-polluting, and high-performance composite board.

[0007] The present application provides a composite board, which comprises the following components by weight: 50-80 parts of modified distiller's grain powder and 10-30 parts of environmentally friendly adhesive; wherein the modified distiller's grain powder is a distiller's grain powder that has been sequentially subjected to wet heat activation treatment and interfacial chemical modification treatment.

[0008] Further, by weight parts, one or more of the following components are further included: 5-15 parts of reinforcing fibers, 1-5 parts of waterproofing agents, 0.5-3 parts of preservatives, and 1-5 parts of plasticizing agents.

[0009] The application also provides a preparation method of the composite board as described above, comprising the following steps: Pre-treatment: drying and crushing the vinasse to obtain vinasse powder; Moisture-heat activation treatment: placing the vinasse powder in a saturated water vapor environment and treating it at 0.2-0.4 MPa and 125-135℃ for 15-30 min; interface chemical modification treatment: mixing and reacting a coupling agent with the moisture-heat activated vinasse powder to obtain modified vinasse powder; hot-pressing forming: mixing the modified vinasse powder with an environmentally friendly adhesive to obtain a premix, and hot-pressing forming to obtain the composite board.

[0010] Further, in the pre-treatment step, the vinasse is first soaked in a weak alkaline solution to neutralize to pH 6.5-7.5, and then centrifuged, dehydrated, and dried.

[0011] Further, the drying temperature of the vinasse is 80-120℃, and the water content after drying is ≤10%; and / or, the particle size of the vinasse powder is 20-200 mesh.

[0012] Further, the coupling agent is a silane coupling agent; and the interface chemical modification treatment specifically comprises: hydrolyzing the silane coupling agent in an ethanol-water solution, and then mixing and reacting it with the moisture-heat activated vinasse powder at 80-100℃ by spraying.

[0013] Further, the hot-pressing forming conditions include: hot-pressing temperature 100-160℃, and hot-pressing pressure ≥0.5 MPa.

[0014] Further, the hot-pressing forming adopts a continuous hot-pressing process; before entering the hot-pressing zone, the premix is first treated in a preheating zone with a temperature of 80-100℃.

[0015] Further, during the hot-pressing forming, a decorative surface material is coated on the upper surface and / or lower surface of the premix, and then it is once-pressed and formed.

[0016] Application of the composite board as described above as packaging materials or decorative materials.

[0017] The beneficial effects of the present application: the modified distiller's grains powder is obtained after specific wet heat activation treatment and interface chemical modification treatment, the composite board material uses the deeply modified distiller's grains powder as the main base material, and is matched with the environment-friendly adhesive, realizes the efficient and environment-friendly utilization of the abundant biomass resource of distiller's grains without relying on the traditional formaldehyde-containing adhesive, realizes the high-value utilization of the whole component of distiller's grains, and develops a completely degradable, pollution-free and excellent performance composite board material. DETAILED DESCRIPTION

[0018] The present application provides a kind of composite board, by weight parts, including the following components: modified distiller's grains powder 50-80 parts, environment-friendly adhesive 10-30 parts;Wherein, the modified distiller's grains powder is the distiller's grains powder sequentially through wet heat activation treatment and interface chemical modification treatment.In this embodiment, the modified distiller's grains powder is obtained after specific wet heat activation treatment and interface chemical modification treatment, the composite board material uses the deeply modified distiller's grains powder as the main base material, and is matched with the environment-friendly adhesive, realizes the efficient and environment-friendly utilization of the abundant biomass resource of distiller's grains without relying on the traditional formaldehyde-containing adhesive, realizes the high-value utilization of the whole component of distiller's grains, and develops a completely degradable, pollution-free and excellent performance composite board material.Modified distiller's grains powder 60-70 parts, environment-friendly adhesive 15-25 parts are preferred.

[0019] Wherein, distiller's grains powder is used as the main base material in main material, provides natural polymer such as cellulose, hemicellulose and lignin, and plays a role of skeleton. Optionally, the auxiliary base material can also be contained in main material, such as auxiliary fiber material, functional filler. Auxiliary fiber material includes rice husk, straw powder, sawdust, etc., to improve the strength and processing performance of the board, and the amount can be 0%-30% of the total weight of main material. Functional fillers include calcium carbonate, talc and other inorganic fillers to adjust the density and cost of the board, and the amount can be 0%-20% of the total weight of main material. Environment-friendly adhesive is selected from starch-based adhesive (such as modified starch), protein-based adhesive (such as soybean protein) or biodegradable synthetic polymer (such as polylactic acid PLA, polycaprolactone PCL, etc.). Preferably, starch-based adhesive, because of its low cost and good compatibility with distiller's grains components. The role of adhesive is to bond the base materials such as distiller's grains powder together to form a board with certain strength.

[0020] Further, one or more of the following components by weight parts: 5-15 parts of reinforcing fibers, 1-5 parts of waterproofing agent, 0.5-3 parts of preservative, 1-5 parts of plasticizer. Reinforcing fibers, waterproofing agent, preservative and plasticizer as optional but important functional additives, the amount range is determined by a large number of experiments, aiming to solve the inherent defects of the substrate of distiller's grains, and has synergistic effect with the core "modified distiller's grains powder-environmental adhesive" system, together constitutes a composite system aiming to balance the mechanical properties, water resistance, durability and processability of the board.

[0021] Wherein, the reinforcing fibers can be selected from natural fibers such as bamboo fibers, hemp fibers or pulp fibers, etc., with a length of 0.5-2mm; the reinforcing fibers are used to improve the tensile strength and impact resistance of the board, and improve the mechanical properties of the board. The waterproofing agent is selected from paraffin, natural wax (such as beeswax), rosin or biodegradable polymer (such as polycaprolactone PCL); the waterproofing agent is used to improve the water resistance of the board, reduce the water absorption rate, and prevent the performance of the board from declining in a humid environment. The preservative is selected from natural preservatives such as tea polyphenol, chitosan or citric acid; the preservative is used to inhibit the growth of microorganisms, prevent the board from mildewing during use, and prolong its service life. The plasticizer is selected from glycerol or citrate; the plasticizer is used to improve the flexibility and processability of the board, reduce the brittleness of the board, and facilitate subsequent cutting and surface treatment. Preferably, the reinforcing fibers are 8-12 parts, the waterproofing agent is 2-4 parts, the preservative is 1-2 parts, and the plasticizer is 2-4 parts.

[0022] The application also provides a preparation method of the composite board as described above, comprising the following steps: Pre-treatment: dry and crush the distiller's grains to obtain distiller's grains powder; specifically, first immerse the fresh distiller's grains in a weak alkaline solution (such as 1-2% sodium bicarbonate solution) to neutralize to pH 6.5-7.5, then centrifugal dewatering, and drying at 80-120℃ to a water content of ≤10%, and then crushing the dried distiller's grains with a grinding mill to 20-200 mesh (preferably 80-200 mesh) to ensure that it has an appropriate specific surface area and fluidity, which is beneficial to subsequent uniform mixing. Wherein, the distiller's grains are preferably grain distiller's grains, including but not limited to liquor distiller's grains, rice wine distiller's grains, beer distiller's grains, etc.; preferably liquor distiller's grains. The weak alkaline solution can be selected from sodium bicarbonate solution, sodium carbonate solution or ammonia solution, etc., preferably sodium bicarbonate solution.

[0023] moisture-activated treatment: the distiller's grains powder is placed in a saturated steam environment, and treated at 0.2-0.4 MPa, 125-135℃ for 15-30 min; wherein the distiller's grains powder is placed in a pressure vessel, and then the environmental conditions are set. This step aims to: ① passivate perishable components: make the residual starch gelatinize, denature the protein, reduce its biodegradability, and improve the board's biological stability; ② activate endogenous adhesives: gelatinized starch and denatured protein can serve as natural adhesive precursors; ③ release polysaccharide network: destroy the yeast cell wall, and make the polysaccharides such as β-glucan in it dissolve, and play a natural gel enhancement role. Interface chemical modification treatment: the coupling agent is mixed and reacted with the moisture-activated distiller's grains powder to obtain modified distiller's grains powder; wherein the coupling agent can be any one or more of silane coupling agent, titanate coupling agent, and aluminate coupling agent, and is preferably silane coupling agent. Specifically, after the silane coupling agent is hydrolyzed in an ethanol-water solution, it is mixed and reacted with the moisture-activated distiller's grains powder at 80-100℃ for 30 min by spraying (using a high-speed spraying device), realizing the grafting of functional groups on the surface of the distiller's grains particles, and greatly improving the interfacial compatibility of the distiller's grains with organic polymers.

[0024] hot-pressing forming: the modified distiller's grains powder (the distiller's grains powder can be combined in different mesh sizes) is mixed with an environmentally friendly adhesive to obtain a premix, which is hot-pressed to produce the composite board. Specifically, the above-processed modified distiller's grains powder is mixed with an environmentally friendly adhesive, reinforcing fibers, a waterproof agent, a preservative, and a plasticizing agent in a high-speed mixer according to the formula proportion. The mixing process can be carried out at room temperature, and the components are fully dispersed and uniform by high-speed stirring to form a premix. The mixing time can be adjusted according to the equipment, and generally the material is mixed uniformly and without clumping. The premix is continuously fed into the feed inlet of a continuous hot press by a screw conveyor. The premix first enters the preheating zone, and the preheating temperature is controlled at 80-100℃, so that the material temperature gradually increases to avoid thermal shock. Subsequently, the premix enters the hot-pressing zone, and the hot-pressing temperature is generally controlled at 100-160℃, preferably 120-150℃. The hot-pressing pressure is adjusted in combination with the required board thickness, and should be sufficient to make the material dense and formed, and generally the hot-pressing pressure ≥0.5 MPa, preferably 2-7 MPa. The material is subjected to uniform hot-pressing between the continuously moving steel belt and the press roller, and the hot-pressing speed (i.e. the steel belt speed) is adjusted according to the board thickness and the adhesive curing requirement, and is generally controlled at 0.2-0.8 m / s. In this process, the environmentally friendly adhesive (such as corn starch adhesive) is further gelatinized and partially cross-linked, firmly bonding the distiller's grains powder and the adhesive, reinforcing fibers, etc. together to form a dense board structure. Further, a covering decorative material can be selected as an optional process according to different application scenarios; if necessary, a decorative material (such as a pre-impregnated environmentally friendly decorative paper with a thickness of 0.2 mm to 0.6 mm) is covered on the upper surface and / or lower surface of the premix, and is once-pressed and formed to improve its decorative performance and surface strength.

[0025] Post-processing: The hot-pressed plate is cut and trimmed as needed, then cooled and shaped to obtain a composite plate of the desired size. Finally, the plate is subjected to necessary surface treatment (such as sanding, spraying of environmentally friendly coatings, etc.) to obtain the final product.

[0026] Through the above process, the core problems solved by the present application mainly include: how to make full use of the rich organic matter in distiller's grains to avoid resource waste; how to avoid using traditional formaldehyde-containing adhesives to achieve environmental protection and pollution-free board; how to overcome the defects of distiller's grains such as easy rancidity, difficult transportation and difficult direct utilization; and how to prepare a degradable composite board with mechanical properties and durability meeting the use requirements through reasonable process design. The composite board can be applied in packaging materials or decorative materials. When used in the packaging field, the thickness of the board is generally 2-3 mm; when used in the decoration field, the thickness of the board can be increased to 20-40 mm to meet the different strength and stiffness requirements.

[0027] Advantages of the present application: (1) The raw materials are environmentally friendly and abundant in source: The present application can use white spirit distiller's grains as the main material, realizing the resource utilization of brewing waste and reducing environmental pollution. Distiller's grains are renewable biomass with wide sources and low price, greatly reducing the production cost of the board. At the same time, by adding auxiliary fibers and fillers, the formula can be further optimized and the resource utilization rate can be improved.

[0028] (2) Fully biodegradable and environmentally friendly: The adhesives and additives (reinforcing fibers, waterproof agents, preservatives and plasticizers) used in the present application are all environmentally friendly materials. For example, starch-based adhesives, protein-based adhesives or biodegradable synthetic polymers (such as PLA, PCL) can be decomposed by microorganisms in the natural environment and do not contain harmful substances. The prepared composite board can be completely biodegraded after the end of its service life, without producing "white pollution", meeting the requirements of green and sustainable development.

[0029] (3) Excellent performance and wide application: Through reasonable proportioning and process optimization, the composite board of the present application has good mechanical properties and durability. Its bending strength and elastic modulus and other indicators can reach or exceed the standard requirements of traditional shaving board. At the same time, by adding waterproof agents and preservatives, the water resistance and mildew resistance of the board are significantly improved, which can adapt to various application environments. The board can be used to make packaging materials such as packaging boxes and pallets, and can also be used for indoor decorative wallboards and floor substrates, etc., with broad application prospects.

[0030] (4) Strong innovation, leading technology: The present application makes full use of the unique composition characteristics of liquor vinasse, and realizes self-bonding or enhanced bonding through an environmentally friendly adhesive, forming a high-performance composite material. This idea is different from the single use of vinasse in the prior art (such as only extracting protein or only using it as fuel), achieving "full component utilization" and having a pioneering significance in the field of high-value utilization of vinasse.

[0031] Example 1: Luzhou-flavor liquor vinasse composite board (for packaging) In this example, Luzhou-flavor liquor vinasse is used as the main material to prepare a packaging composite board with a thickness of 3 mm. The composition of Luzhou-flavor liquor vinasse is different from that of Maotai-flavor liquor vinasse, with generally higher content of crude fiber and relatively lower content of protein and fat. Therefore, the proportions of adhesive and reinforcing fiber are appropriately adjusted in the formula to obtain the desired performance.

[0032] Formula composition (by weight): Luzhou-flavor liquor vinasse powder: 70 parts Soybean protein adhesive: 12 parts Hemp fiber (reinforcing fiber): 10 parts Rosin (waterproof agent): 4 parts Chitosan (preservative): 1.5 parts Citrate ester (plasticizer): 2.5 parts Preparation process: 1. Raw material treatment Pretreatment: Fresh Luzhou-flavor liquor vinasse is soaked in 1% sodium bicarbonate solution to neutralize to pH 7.0, centrifuged to remove water, dried at 110°C to a moisture content of 8%, and pulverized to 120 mesh to obtain vinasse powder.

[0033] Wet heat activation treatment: The vinasse powder is placed in a cooking pot and saturated steam is introduced, and it is treated at 0.3 MPa and 130°C for 20 min for wet heat activation.

[0034] Interface chemical modification treatment: After hydrolysis of silane coupling agent KH-550 with 95% ethanol, it is uniformly sprayed onto the activated vinasse powder, and stirred at 90°C for 30 min to complete the surface modification, obtaining modified vinasse powder.

[0035] 2. Mixing ingredients The modified distiller's grains powder, soybean protein adhesive, hemp fiber, rosin, chitosan and citric acid ester are put into a high-speed mixer according to the formula, and stirred at room temperature for 15 min to make the components uniformly mixed. The soybean protein adhesive has good compatibility with the protein in the distiller's grains, and can form strong bonding force; the hemp fiber enhances the bearing capacity of the board; the rosin improves water resistance; the chitosan provides antiseptic effect; and the citric acid ester improves the toughness of the board as a plasticizer.

[0036] 3. Hot-pressing forming The premix is continuously fed into the feeding port of the continuous hot press through a screw conveyor. The material first enters the preheating zone, and the preheating temperature is controlled at 100-120℃ to gradually increase the temperature of the material. Then, the material enters the hot-pressing zone, and the hot-pressing temperature is controlled at 150℃, and the pressure is controlled at 3 MPa by a hydraulic system. The material is uniformly subjected to hot-pressing between the continuously moving steel belt and the compression roller, and the steel belt speed is controlled at 0.6 m / s to ensure that the material obtains the required hot-pressing time in the hot-pressing zone. In this process, the soybean protein adhesive undergoes cross-linking reaction at high temperature to form a firm network structure with the protein, cellulose and the like in the distiller's grains powder. A layer of 0.2 mm thick pre-impregnated environment-friendly decorative paper is coated on the upper or lower surface of the premix during hot-pressing forming, and the premix is hot-pressed into a board at one time. After hot-pressing, the board enters the cooling zone, and the temperature of the board is reduced to room temperature by the air cooling system for solidification and setting.

[0037] 4. Post-processing The continuously output board is cut and edged according to 787 mm*1092 mm*2 mm to obtain a 2 mm thick board, and further cut and V-grooved (away from the decorative paper side) according to the design size of the packaging structure, and then laminated with a printed paper to form a substitute material for gray board or medium-density board.

[0038] Example 2: Jiangxiang Baijiu distiller's grains composite board (for decoration) In this example, Jiangxiang Baijiu distiller's grains are used as the main material to prepare a 20 mm thick composite board for building decoration. Jiangxiang Baijiu distiller's grains have unique brewing process, and their composition is different from that of Luzhang and Qingxiang Baijiu, generally containing higher protein and fat, as well as more aroma substances. These components may affect the performance of the board, so they need to be considered in the formula design.

[0039] Raw material composition (weight parts): Jiangxiang Baijiu distiller's grains powder: 65 parts Starch-based adhesive (corn starch modified adhesive): 20 parts Bamboo fiber (length about 1 mm): 10 parts Paraffin (waterproof agent): 2 parts Tea polyphenol (antiseptic): 1 part Glycerol (plasticizer): 2 parts Preparation process: 1. Raw material processing: Pre-treatment: Fresh Luzhou-flavor liquor lees were soaked with 2% sodium bicarbonate solution to neutralize to pH 6.8, centrifuged to remove water, dried at 100℃ to a moisture content of 9%, and pulverized to 100 mesh to obtain lees powder.

[0040] Wet-heat activation treatment: The lees powder was placed in a cooking pot, saturated water vapor was introduced, and wet-heat activation was performed at 0.25 MPa and 125℃ for 25 min.

[0041] Interfacial chemical modification treatment: After hydrolysis of silane coupling agent KH-550 with 95% ethanol, it was uniformly sprayed onto the activated lees powder, and surface modification was completed by stirring at 85℃ for 30 min.

[0042] 2. Mixing ingredients The above lees powder, corn starch modified adhesive, bamboo fiber, paraffin, tea polyphenol, and glycerol were put into a high-speed mixer according to the formula ratio, stirred at high speed for 10 min at room temperature to make the components fully mixed and uniform, and a premix was obtained. The addition of bamboo fiber can improve the strength and toughness of the board, paraffin as a waterproof agent can reduce the water absorption, tea polyphenol can provide anti-corrosion function, and glycerol can improve the flexibility of the board.

[0043] 3. Hot-pressing molding The premix was continuously fed into the feeding port of a continuous hot press through a screw conveyor. The material first entered the preheating zone, and the preheating temperature was controlled at 80-100℃ to gradually increase the material temperature and avoid thermal shock. Then, the material entered the hot-pressing zone, and the hot-pressing temperature was controlled at 120℃, and the pressure was controlled at 5 MPa by a hydraulic system. The material was uniformly subjected to hot-pressing between the continuously moving steel belt and the compression roller, and the steel belt speed was controlled at 0.5 m / s to ensure that the material obtained the required hot-pressing time in the hot-pressing zone. During this process, the corn starch adhesive was gelatinized and partially cross-linked to firmly bond the lees powder and bamboo fiber together. A 0.3 mm thick pre-impregnated environmentally friendly decorative paper was laminated on the upper and lower surfaces of the premix during hot-pressing molding to improve the decorative performance and surface strength of the board. After hot-pressing, the board entered the cooling zone, and the water cooling system was used to reduce the board temperature to room temperature for solidification and setting.

[0044] 4. Post-treatment The continuously output board was cut, edged, and then tested for performance according to 400*400*20mm.

[0045] Example 3: Qing-flavor liquor lees composite board (for packaging) This example uses the light-flavor liquor vinasse as raw material to prepare a composite board with a thickness of 40 mm for decoration or structural use in special occasions. The light-flavor liquor vinasse has a composition between that of the Maotai-flavor and the Luzhou-flavor liquor, with moderate protein and fat content and less starch content, but usually contains more fillers such as rice hulls. Therefore, the amount of auxiliary fiber is increased in the formula, and modified corn starch is selected as the adhesive to obtain higher strength and durability.

[0046] Formula composition (by weight): Light-flavor liquor vinasse powder: 60 parts Modified corn starch (adhesive): 22 parts Paper pulp fiber (reinforcing fiber): 10 parts Beeswax (waterproof agent): 5 parts Citric acid (preservative): 1 part Glycerol (plasticizer): 2 parts Preparation process: 1. Raw material treatment Pretreatment: Fresh light-flavor liquor vinasse is soaked with 1.5% sodium bicarbonate solution to neutralize to pH 7.2, centrifuged to remove water, dried at 105°C to a moisture content of 7%, and pulverized to 150 mesh to obtain vinasse powder.

[0047] Wet heat activation treatment: The vinasse powder is placed in a cooking pot and saturated steam is introduced, and treated at 0.35 MPa and 135°C for 15 min for wet heat activation.

[0048] Interface chemical modification treatment: Silane coupling agent KH-550 is hydrolyzed with 95% ethanol and uniformly sprayed onto the activated vinasse powder, and stirred at 95°C for 30 min to complete the surface modification.

[0049] 2. Mixing ingredients The vinasse powder, modified corn starch, paper pulp fiber, beeswax, citric acid, and glycerol are put into a high-speed mixer according to the formula, and stirred at room temperature for 12 min to mix the components uniformly. Modified corn starch is a kind of adhesive obtained by esterification and oxidation modification of corn starch, which has good bonding performance and strength; beeswax as a waterproof agent has a low melting point, which can melt and penetrate into the vinasse powder during hot pressing to improve the water resistance of the board; paper pulp fiber is used as an auxiliary fiber to reinforce the board; citric acid provides corrosion protection; glycerol improves the toughness of the board.

[0050] 3. Hot pressing The premix is continuously fed into the feeding port of the continuous hot press by the screw conveyor. The material first enters the preheating zone, and the preheating temperature is controlled at 120-140°C, so that the temperature of the material gradually increases. Then, the material enters the hot pressing zone, and the hot pressing temperature is controlled at 180°C, and the pressure is controlled at 7 MPa by the hydraulic system. The material is uniformly hot-pressed between the continuously moving steel belt and the compression roller, and the required hot-pressing time of the material in the hot-pressing zone is ensured by controlling the steel belt speed at 0.2 m / s. In this process, the modified corn starch melts and partially crosslinks at high temperature, and forms a dense composite material with cellulose, lignin and other substances in the distiller's grains. The beeswax is also in a molten state at this temperature, filling the internal pores of the board, further improving the density and water resistance of the board. A layer of 0.4 mm thick pre-impregnated environmentally friendly decorative paper is covered on the upper and lower surfaces of the premix during hot pressing, and the premix is hot-pressed into a board at one time to improve the decorative performance and surface strength of the board. After hot pressing, the board enters the cooling zone, and the temperature of the board is reduced to room temperature by the water cooling system, and is solidified and shaped.

[0051] 4. Post-processing: The continuously output boards are cut and edged according to the required length, and a layer of thin wood veneer or environmentally friendly decorative paper is pasted on the surface. Finally, the performance of the board is tested.

[0052] Comparative Example - No activation and modification treatment: The formula composition and preparation process of the comparative example are different from those of Example 2 only in that the distiller's grains are not subjected to wet heat activation treatment and interfacial chemical modification treatment, and the other conditions are the same.

[0053] Performance test: To verify the performance advantages of the composite board of the present application, the composite boards prepared in Examples 1-3 and Comparative Example - No activation and modification treatment, and commercially available traditional shaving board and medium density board were subjected to performance comparison test. The comparison boards are commercially available urea-formaldehyde resin bonded shaving board (thickness of 20 mm, density of about 0.65 g / cm³), and commercially available ordinary medium density fiberboard (thickness of 3 mm, density of about 0.7 g / cm³). The test results are shown in the following table:

[0054] Through analysis of the data in the above table, it can be concluded that: (1) The comprehensive performance of the composite board of the present application is significantly better than that of traditional shaving board, and reaches the level of medium-density fiber board. The mechanical properties are all better: in the key bending strength, elastic modulus and internal bond strength, the three embodiments (23-30 MPa, 2500-3500 MPa, 0.65-0.80 MPa) are all much higher than those of the comparative shaving board (11 MPa, 1600 MPa, 0.40 MPa). Especially in the internal bond strength (IB), the embodiments are 60%-100% higher than the shaving board, which is direct evidence of the firm internal adhesion and non-delamination of the board. Balance between density and performance: the density (0.95-1.10 g / cm 3 ) of the composite board of the present application is higher than that of traditional boards, and the high density of the present application is mainly derived from the efficient reconstruction of distiller's grain waste: through wet-heat activation and interfacial chemical modification, the distiller's grain particles are densified and wrapped by a strong and tough interfacial layer, and then combined with a small amount of environmentally friendly adhesive to form an intrinsically dense composite structure. This process abandons the dependence on scarce wood resources and a large amount of synthetic adhesives, and instead, through ingenious process design, it converts low-value waste into a high-performance matrix, achieving a synergistic optimization of resources, environment and material performance from the source, and showing higher material design efficiency.

[0055] (2) The core process (wet-heat activation + interfacial modification) of the present application is the decisive factor for performance improvement. Direct comparison with the "no activation modification treatment" comparative example: the performance of the board (density 1.0 g / cm 3 ) of the comparative example is overall and significantly lower than that of embodiment 2 (same thickness 20 mm) treated by the complete process, specifically in bending strength (25 vs 28 MPa), internal bond strength (0.60 vs 0.75 MPa). This clearly proves that only physical mixing and hot pressing without "wet-heat activation" and "interfacial chemical modification" of the present application cannot achieve optimal performance. The two steps of "wet-heat activation treatment" and "interfacial chemical modification treatment" are indispensable and synergistic for activating the endogenous adhesion of distiller's grain and strengthening the interfacial bonding.

[0056] (3) The 24-hour water absorption rate (5%-8%) of the three embodiments is the same as that of shaving board (8%) and significantly better than that of medium-density fiber board (12%). This shows that by adding waterproofing agents (such as rosin, beeswax) and a dense interfacial structure, the board of the present application overcomes the problem of strong hydrophilicity of biomass materials and has practical moisture resistance. Raw material universality verification: three types of distiller's grain with obvious differences in ingredients, such as strong-flavor, sauce-flavor and light-flavor, can all produce boards with excellent performance after being treated by the process of the present application, and show regular changes (such as the light-flavor distiller's grain board has the highest strength). This proves the wide applicability of the process of the present application to different sources of distiller's grain, rather than being applicable only to a specific type, greatly improving the industrial value of the technology.

[0057] In summary, the composite board prepared by the present application is significantly superior to commercially available shaving board in terms of bending strength, elastic modulus and internal bonding strength, and has equivalent or lower water absorption rate and better water resistance. In addition, the mechanical properties of the composite board prepared by the present application, such as bending strength, elastic modulus and internal bonding strength, can reach the level of medium-density board with the same thickness. What is particularly important is that compared with the control sample which has not undergone "wet heat activation" and "interfacial chemical modification" treatment, the internal bonding strength and other indicators of the board of the present application are significantly improved, which directly proves the key and irreplaceable nature of the core processing steps for improving the performance of the distiller's grains-based board. The board of the present application does not contain harmful substances such as formaldehyde and is biodegradable; the main performance is that all components (distiller's grains powder, protein-based adhesive, natural fiber, biodegradable polymer, tea polyphenol and glycerol) of the present application are derived from natural renewable materials, and no synthetic resin containing formaldehyde is introduced in the whole process, so the obtained board fundamentally eliminates formaldehyde pollution; the main components can be naturally decomposed by microorganisms under composting conditions, achieving full biodegradation. While the traditional shaving board continuously releases formaldehyde during use, which causes harm to the environment and human health. This fully proves the double advantages of the composite board of the present application in performance and environmental protection. The above data fully show that the present application successfully converts distiller's grains waste into a high-value environmental protection material with excellent mechanical properties and good durability.

[0058] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A composite board material, characterized by, The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification.

2. The composite sheet of claim 1, wherein The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer.

3. A method of producing a composite sheet as claimed in claim 1 or 2, characterized in that The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification. The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer. The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification. The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer.

4. The method of claim 3, wherein the step of applying the adhesive is performed after the step of applying the second layer of the composite sheet. The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification.

5. The method of claim 3, wherein the step of applying the adhesive is performed by using a roll coater. The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer.

6. The method of claim 3, wherein the step of applying the adhesive is performed by using a roll coater. The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification.

7. The method for preparing the composite board as described in claim 3, characterized in that, The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer.

8. The method for preparing the composite board as described in claim 7, characterized in that, The composite board is prepared by mixing modified distiller's grains and an environmental protection adhesive, and the modified distiller's grains are prepared by wet heat activation and interface chemical modification.

9. The method for preparing the composite board as described in claim 3, characterized in that, The composite board further comprises one or more of the following components: 5-15 parts by weight of reinforcing fibers, 1-5 parts by weight of waterproofing agent, 0.5-3 parts by weight of preservative, and 1-5 parts by weight of plasticizer.

10. Use of the composite board of claim 1 or 2 as a packaging material or a decorative material.

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