All-biomass multifunctional material and preparation method and application thereof

Abstract

This invention relates to the field of adhesives and coatings, specifically to a fully bio-based multifunctional material, its preparation method, and its applications. The fully bio-based multifunctional material provided by this invention is obtained from a eutectic solvent and tannic acid; the eutectic solvent includes vanillin and cinnamaldehyde. The fully bio-based multifunctional material provided by this invention exhibits strong adhesion to poplar boards and similar materials, and the MDF prepared using this material with bamboo powder also shows superior performance compared to current high-density fiberboard, making it an excellent alternative to MDF and plastic boards. Furthermore, the fully bio-based multifunctional material provided by this invention, as a coating, exhibits strong adhesion to various substrates, and the coating is simple to prepare, non-toxic, harmless, and easy to spray, making it an excellent alternative to organic coatings such as paints and water-based coatings. Therefore, the fully bio-based multifunctional material of this invention also has broad application prospects as an adhesive in the field of MDF or in the field of coatings.

Description

Technical Field

[0001] This invention relates to the field of adhesives and coatings, specifically to fully bio-based multifunctional materials, their preparation methods, and applications. Background Technology

[0002] Currently, the most commonly used adhesives on the market are urea-formaldehyde resin and phenolic resin. However, these adhesives contain formaldehyde, a volatile and toxic compound, which can harm human health and the environment. When using these adhesives to prepare MDF (medium-density fiberboard), it is often not usable immediately; the formaldehyde must be allowed to dissipate before use. Therefore, a green, environmentally friendly, non-toxic, and inexpensive adhesive is needed.

[0003] To address the adhesive problem, current technologies for replacing these adhesives include using lignin to replace phenol and furfural, glyoxal, and other less toxic and less volatile aldehydes to replace formaldehyde. However, due to the low activity of lignin, it almost always requires modification. This not only increases the processing steps and costs but also cannot guarantee that toxic and harmful substances will not be generated during the process, making it difficult to achieve true green and environmentally friendly practices.

[0004] Furthermore, most commercially available paint coatings contain volatile organic solvents such as formaldehyde, benzene, and toluene, which can cause serious harm to human health and significant environmental pollution. People need a non-toxic, harmless, environmentally friendly, and inexpensive coating to replace them.

[0005] To address this coating challenge, related technologies have used water-based coatings instead of solvent-based coatings. While water-based coatings solve the problem of volatile organic solvents, they still require petrochemical products such as acrylic acid and polyurethane for synthesis, resulting in higher costs and more complex production processes. Therefore, a non-petroleum-based, low-cost coating is needed to replace them. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a fully bio-based multifunctional material, its preparation method and application. The fully bio-based multifunctional material provided by the present invention can be prepared from natural biomass materials, which is green, environmentally friendly, non-toxic and harmless. It also has a variety of functional applications. When used as an adhesive, it has strong bonding strength to wood or wood raw materials and can be used directly as an adhesive. When used as a coating material, it has strong adhesion to different substrates.

[0007] This invention provides a fully bio-based multifunctional material obtained from a eutectic solvent and tannic acid;

[0008] The eutectic solvents include vanillin and cinnamaldehyde.

[0009] The eutectic solvent of this invention comprises vanillin and cinnamaldehyde, wherein vanillin acts as a hydrogen bond donor and cinnamaldehyde acts as a hydrogen bond acceptor. When mixed in a certain ratio, they can form stable hydrogen bonds, resulting in a clear and transparent eutectic solvent. The molar ratio of cinnamaldehyde to vanillin in this invention is 1:(0.8~1.2), preferably 1:1. Preliminary experiments show that a large or small number of hydrogen bond donors will prevent the formation of stable hydrogen bond structures.

[0010] The tannic acid, vanillin, and cinnamaldehyde described in this invention are all derived from biomass raw materials, which are inexpensive, readily available, and avoid the introduction of substances such as phenol and formaldehyde, making the product more environmentally friendly. In some embodiments of this invention, the tannic acid is derived from: bean pods, cork oak leaves, or Sicilian sumac leaves; the vanillin compound is derived from: vanilla beans or beets; and the cinnamaldehyde compound is derived from: cinnamon bark.

[0011] This invention also provides a method for preparing the fully bio-based multifunctional material described in any of the above technical solutions, comprising the following steps: reacting a eutectic solvent and tannic acid to obtain the fully bio-based multifunctional material. The eutectic solvent and tannic acid used in this invention are the same as described above and will not be repeated here.

[0012] The eutectic solvent of this invention is obtained by mixing vanillin and cinnamaldehyde. Specifically, the eutectic solvent is obtained by mixing vanillin and cinnamaldehyde in a molar ratio of 1:(0.8~1.2). Preferably, the eutectic solvent is obtained by mixing vanillin and cinnamaldehyde in a molar ratio of 1:1. The mixing temperature of this invention is 80℃~100℃, and the mixing time is 20 min~40 min.

[0013] This invention first reacts a eutectic solvent with tannic acid. Specifically, the eutectic solvent and tannic acid are dispersed before the reaction. In some embodiments of this invention, the tannic acid is evenly dispersed in the eutectic solvent before the reaction. The dispersion temperature is 80℃~100℃, preferably 90℃, and the dispersion time is 2h~4h. This invention uses a mixture of vanillin and cinnamaldehyde to prepare a eutectic solvent, which can disperse tannic acid, allowing for sufficient contact between the tannic acid and the eutectic solvent, thus making the reaction more complete. This eliminates the use of organic solvents, ensuring that the reaction produces no waste, achieving a "one-pot, three-step" material preparation method that is simple, efficient, generates little waste, and is easily industrialized.

[0014] This invention involves reacting a eutectic solvent with tannic acid at a temperature of 120°C to 140°C for 12 to 14 hours. The temperature of 120-140°C is raised to achieve the polymerization reaction between tannic acid and the eutectic solvent. The reaction concludes after 12-14 hours, yielding an adhesive material with optimal performance.

[0015] This invention involves reacting a eutectic solvent with tannic acid, specifically by reacting the eutectic solvent, tannic acid, and an alkaline catalyst in a mass ratio of 1:(1~1.2):(0~0.05), preferably 1:1.1:(0~0.05). In some embodiments of this invention, 10 g of eutectic solvent, (10~12) g of tannic acid, and (0~0.5) g of alkaline catalyst are reacted. The alkaline catalyst of this invention includes at least one of sodium hydroxide, sodium carbonate, or sodium bicarbonate. If there is too little tannic acid, it cannot react completely with the eutectic solvent, resulting in an excess of eutectic solvent, which reduces the viscosity of the system and prevents the product from gelling. If there is too much tannic acid, the excess tannic acid will be incorporated into the resulting material, leading to a decrease in various properties of the material. Therefore, when the mass ratio of eutectic solvent to tannic acid is close to 1:1.1, the resulting all-biomass-based multifunctional material exhibits the best performance.

[0016] This invention also provides the application of any of the aforementioned fully bio-based multifunctional materials as adhesives or coating materials. The fully bio-based multifunctional material of this invention can be used as an adhesive, either directly or in combination with additives. When used directly as an adhesive, it exhibits high bonding strength to poplar wood boards; at room temperature, its bonding strength to poplar is 4.7 (±0.2) MPa, far exceeding the national standard GB / T 14732-2017 requirement of ≥0.7 MPa for phenolic resin wood adhesives. Furthermore, in the eutectic solvent and tannic acid used to prepare the fully bio-based multifunctional material of this invention, vanillin, as a food additive, and cinnamaldehyde, as a synthetic food flavoring, are both non-toxic, harmless, and inexpensive, making them excellent substitutes for formaldehyde. Tannic acid, as a natural organic compound, is inexpensive and is also an excellent substitute for phenol. Therefore, the fully bio-based multifunctional material of this invention is more environmentally friendly, has a simpler process, and is less expensive than phenolic resin and urea-formaldehyde resin adhesives.

[0017] The fully bio-based multifunctional material described in this invention can also be used as a coating material. It can be used directly as a coating material by ultrasonic dispersion in a solvent, or it can be used in combination with additives as a coating material by ultrasonic dispersion in a solvent, followed by drying of the solvent. The solvent can be selected from at least one of ethanol, water, or acetone, preferably ethanol, and the mass ratio of the fully bio-based multifunctional material to the solvent is 1:(4~9).

[0018] This invention also provides a product that can be a glued product, obtained from wood raw materials and an adhesive, wherein the adhesive includes the fully bio-based multifunctional material described in any of the above technical solutions and optional additives. In some embodiments of this invention, the glued product is a high-performance density board, which is obtained by mixing the fully bio-based multifunctional material and bamboo powder at a mass ratio of 1:(1~3), followed by hot pressing at 110℃~130℃ and 20 MPa~40 MPa, and then allowing it to cool naturally. The performance of the high-performance density board far exceeds that of currently available high-density fiberboard, with a bending strength of 44.12 (±2.25) MPa, while the bending strength of commercially available high-density fiberboard is only 20 (±2.5) MPa. In comparison, the high-performance density board obtained by this invention has superior performance, is more environmentally friendly, and has a lower cost. Preferably, the optimal mass ratio of the fully bio-based multifunctional material and bamboo powder is 1:2. Preliminary experiments revealed that if too much bamboo powder is used, the performance will decrease, while if too little bamboo powder is used, the performance will not improve much, but the cost will increase.

[0019] The product provided by this invention can also be a coating product, comprising a substrate and a coating disposed on the substrate. The coating is formed from a coating material comprising the fully bio-based multifunctional material described in any of the above technical solutions and optional additives. The substrate of this invention includes iron sheets, stainless steel plates, wood boards, or bamboo boards, etc. In some embodiments of this invention, the fully bio-based multifunctional material is mixed with ethanol and ultrasonically dispersed to obtain an ethanol dispersion of the fully bio-based multifunctional material. The dispersion is sprayed onto the substrate and dried at 50°C to 70°C for 0.5 h to 1.5 h, preferably at 60°C for 1 h, to form a coating on the substrate. The coating formed by the fully bio-based multifunctional material of this invention, after adhesion testing, achieves an adhesion level of 5B (optimal) according to ASTM D3359-17 standard.

[0020] This invention provides a fully bio-based multifunctional material, its preparation method, and its applications. The fully bio-based multifunctional material provided by this invention exhibits strong bonding strength to poplar boards, and the MDF prepared using this material with bamboo powder also shows superior performance compared to current high-density fiberboard, making it an excellent alternative to MDF and plastic boards. The process for preparing adhesive products using the fully bio-based multifunctional material described in this invention is simple, the raw materials are all derived from plants, are non-toxic and harmless, low in cost, and generate no by-products during production, making it green and environmentally friendly. It can be used as a safe, reliable, and highly stable adhesive in furniture and industrial applications, improving the quality of adhesives used in wood, and has significant economic and social benefits with a broad market prospect. Therefore, the fully bio-based multifunctional material described in this invention has broad application prospects as an adhesive in the MDF field. Furthermore, the fully bio-based multifunctional material provided by this invention, as a coating, exhibits strong adhesion to iron sheets, stainless steel sheets, wood boards, bamboo boards, etc. This coating is simple to prepare, non-toxic and harmless, and easy to spray, making it an excellent alternative to organic coatings such as paints and water-based coatings. Therefore, this material also has broad application prospects in the coating field. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the bonding strength of the all-biomass-based multifunctional material prepared in Example 1 of the present invention at room temperature;

[0022] Figure 2 This is a schematic diagram of the density board prepared in Embodiment 2 of the present invention and its bending strength;

[0023] Figure 3 This is a schematic diagram of the adhesion test of the all-biomass-based multifunctional material prepared in Example 3 of the present invention to an iron sheet. Detailed Implementation

[0024] This invention discloses a fully bio-based multifunctional material, its preparation method, and its applications. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0025] The present invention will be further described below with reference to the embodiments:

[0026] Example 1

[0027] Preparation of a fully biomass-based multifunctional material: 4.9 g of cinnamaldehyde and 5.65 g of vanillin were mixed at a molar ratio of 1:1 and stirred at 90 °C for 20 min to obtain a clear and transparent eutectic solvent. 10 g of tannic acid was added to the eutectic solvent, along with 0.3 g of sodium bicarbonate catalyst. After stirring for 2 h, when the tannic acid was completely dispersed in the eutectic solvent, the temperature was raised to 120 °C and stirred for 12 h to obtain the fully biomass-based multifunctional material. The mass ratio of the eutectic solvent to tannic acid was 1:1.

[0028] The bonding strength of this all-biomass-based multifunctional material to poplar boards was tested. The specific testing procedure is as follows:

[0029] 1) Sample preparation: Take 0.2 g of the all-biomass-based multifunctional material prepared in Example 1 and apply it while hot to approximately one-quarter (15 × 20 mm) of the sample. 2 The sample was coated onto a poplar wood chip sample (20 mm × 60 mm × 3 mm). A portion of the coated sample was placed in a hot press and hot-pressed at 1.5 MPa and 120℃ for 10 min, then slowly cooled to room temperature and continued to be cold-pressed for 10 h.

[0030] 2) Room temperature (25℃) bonding performance test: After cold pressing, the sample was placed at room temperature for 10 h, and then the bonding performance was tested using a tensile tester at a speed of 5 mm / min. The bonding strength was recorded as the maximum tensile strength.

[0031] like Figure 1 As shown, Figure 1 This is a schematic diagram showing the bonding strength of the all-biomass-based multifunctional material prepared in Example 1 of the present invention at room temperature. Figure 1 It can be seen that the biomass-based multifunctional material has strong bonding strength. At room temperature, its bonding strength to poplar wood can reach 4.7 MPa, which far exceeds the bonding strength (≥0.7 MPa) required by the national standard GB / T14732-2017 for phenolic resin wood adhesives. This shows that the biomass-based multifunctional material provided by the present invention can meet the application needs of daily life as an adhesive.

[0032] Example 2

[0033] Preparation of high-performance MDF: The all-biomass-based multifunctional material obtained in Example 1 was mixed with bamboo powder at a mass ratio of 1:2, and then hot-pressed at 110°C and 20 MPa for 20 min. After natural cooling, a high-strength MDF was obtained. The bending strength was tested using the three-point bending method.

[0034] like Figure 2 As shown, Figure 2This is a schematic diagram showing the density board prepared in Embodiment 2 of the present invention and its bending strength. Figure 2 It can be seen that its bending strength is 44.21 (±2.25) MPa. This far exceeds the bending strength of commercially available high-density fiberboard, which is 20 (±2.5) MPa, indicating that the high-performance density board provided by this invention can be used as an excellent alternative to high-density fiberboard.

[0035] Example 3

[0036] Preparation of ethanol dispersion of all-biomass multifunctional material: The all-biomass-based multifunctional material obtained in Example 1 was mixed with ethanol at a mass ratio of 1:4, and then ultrasonicated to form a uniform dispersion. The dispersion was then sprayed onto an iron sheet and dried at 60°C for 1 h. After adhesion testing, according to ASTM D3359-17 standard, its adhesion reached Class 5B (optimal level).

[0037] like Figure 3 As shown, Figure 3 This is a schematic diagram of the adhesion test of the all-biomass-based multifunctional material prepared in Example 3 of the present invention to an iron sheet. Figure 3 The image on the left shows the coating after it has been divided into grids; the image in the middle shows the test with tape applied to the grid; and the image on the right shows the grid after the tape has been torn off according to standard procedures. From Figure 3 As can be seen from the three pictures, there are no obvious signs of peeling off the coating in the grid before and after the test. According to the ASTM D3359-17 standard, its adhesion can reach Class 5B (the best level).

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A fully biobased multifunctional material, characterized in that, The low eutectic solvent and tannic acid are used to prepare the full-bio-based multifunctional material. The low eutectic solvent comprises vanillin and cinnamaldehyde. The molar ratio of the cinnamaldehyde to the vanillin is 1:(0.8-1.2). The preparation method of the full-bio-based multifunctional material comprises the following steps: The low eutectic solvent, tannic acid and alkali catalyst are reacted in a mass ratio of 1:(1-1.2):(0-0.05) to obtain the full-bio-based multifunctional material. The reaction temperature is 120-140 DEG C, and the reaction time is 12-14 h.

2. The fully biobased multi-functional material of claim 1, wherein, The tannic acid, vanillin and cinnamaldehyde are all derived from biomass raw materials.

3. The method for producing a fully biobased multifunctional material according to any one of claims 1 to 2, characterized in that, The preparation method of the full-bio-based multifunctional material comprises the following steps: The low eutectic solvent, tannic acid and alkali catalyst are reacted in a mass ratio of 1:(1-1.2):(0-0.05) to obtain the full-bio-based multifunctional material. The reaction temperature is 120-140 DEG C, and the reaction time is 12-14 h.

4. The production method according to claim 3, characterized by, The low eutectic solvent and tannic acid are dispersed and then reacted, the dispersion temperature is 80-100 DEG C, and the dispersion time is 2-4 h.

5. The preparation method according to claim 3, characterized in that, The low eutectic solvent is obtained by mixing the cinnamaldehyde and vanillin. The mixing temperature is 80-100 DEG C, and the mixing time is 20-40 min.

6. The full-bio-based multifunctional material according to any one of claims 1-2 is used as an adhesive or coating material.

7. A product characterised in that, The product is a glued product, which is obtained from wood raw materials and an adhesive, and the adhesive comprises the full-bio-based multifunctional material according to any one of claims 1-2 and optional additives. Alternatively, The product is a coated product, which comprises a substrate and a coating arranged on the substrate, and the coating is formed by a coating material comprising the full-bio-based multifunctional material according to any one of claims 1-2 and optional additives.

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