A formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate

Abstract

This invention discloses a formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate, belonging to the field of agricultural solid waste resource utilization technology. The formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate comprises the following raw materials in parts by weight: 60-65 parts oyster mushroom substrate powder, 4-6 parts epoxidized soybean oil, 2-3 parts citric acid, 4-6 parts surfactant, and 5-8 parts water. A method for preparing the formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate is also provided. The high-strength oyster mushroom substrate board obtained by this invention achieves mechanical properties equivalent to or better than those of particleboard according to the national standard (GB / T 4897-2015), solving the problems of high energy consumption, low preparation efficiency, and poor waterproof performance of formaldehyde-free oyster mushroom substrate board, and has good economic benefits. The biomass board prepared by this method has a simple process flow, is easy to mass-produce, and has good commercial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of agricultural solid waste resource utilization technology, and more specifically relates to a formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate. Background Technology

[0002] With the improvement of people's living standards, the production of edible fungi has increased year by year, and the amount of mushroom substrate waste has also shown an increasing trend. Currently, the main ways to process collectable mushroom substrate are through composting, biomass energy conversion, animal feed production, and the manufacture of bio-based materials. However, these methods only consume a small portion of the mushroom substrate; the vast majority is simply landfilled or incinerated, wasting biomass resources and causing serious pollution to water, soil, and air environments. How to achieve effective processing of mushroom substrate, conserve resources and energy, protect the ecological environment, and improve agricultural efficiency is of great significance for promoting low-carbon agricultural development and addressing climate change.

[0003] Mushroom substrate spawn is mainly composed of sawdust, cottonseed hulls, and rice straw, and is rich in lignin, cellulose, and hemicellulose, similar in chemical composition to wood. Therefore, mushroom substrate spawn is a high-quality raw material for preparing non-wood-based panels. However, current methods for preparing panels based on mushroom substrate spawn face the following problems:

[0004] (1) The hot-pressing process in the preparation of biomass boards is energy-intensive and has low production efficiency. Currently, the preparation of biomass boards mainly adopts the hot-pressing method. For example, existing technologies disclose a method for preparing formaldehyde-free composite boards using corn stalks and mushroom substrate. The hot-pressing temperature required for board preparation is 190℃, the hot-pressing time is as long as 2 hours, and the natural cooling time is as long as 3 hours. The hot-pressing time required for board preparation is long, the energy consumption is large, and the production efficiency is low. Therefore, developing an energy-saving and efficient board preparation technology based on mushroom substrate is of great significance to the development of the biomass board research field.

[0005] (2) Poor waterproof performance. Although the mycelial layer in mushroom substrate has a certain degree of waterproof performance, the waterproof performance of boards made from untreated mushroom substrate is poor due to the influence of many hydrophilic hydroxyl functional groups contained in mushroom substrate. It is difficult to meet the national standard requirements. Therefore, further improving the waterproof performance of mushroom substrate-based boards is a hot problem in the field of biomass board research. Summary of the Invention

[0006] Different types of mushroom mycelium contain significantly different chemical compositions. Studies have found that, without the addition of any additional chemical reagents, boards prepared using oyster mushroom substrate as raw material via hot pressing exhibit stronger mechanical properties compared to boards made from other mushroom substrates. Therefore, the purpose of this invention is to provide a novel formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate, addressing the problems of the existing technology and achieving the preparation of an energy-efficient, highly waterproof, and formaldehyde-free composite board using oyster mushroom substrate waste.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of this invention is to provide a formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate, comprising the following raw materials in parts by weight:

[0009] The ingredients are 60-65 parts of oyster mushroom spawn powder, 4-6 parts of epoxidized soybean oil, 2-3 parts of citric acid, 4-6 parts of surfactant, and 5-8 parts of water.

[0010] Epoxidized soybean oil was chosen because of its environmental friendliness, low toxicity, renewability, and low cost. Citric acid was chosen because: 1. Citric acid is a tribasic acid; compared to dibasic and monobasic acids, under hot-pressing conditions, it undergoes esterification with hydroxyl groups to form a more complex cross-linked network, thereby effectively improving the mechanical properties of the board; 2. Compared to other polycarboxylic acids, it has better water solubility, which is more conducive to its uniform dispersion in surfactants.

[0011] Preferably, the oyster mushroom spawn powder is obtained by grinding and sieving oyster mushroom spawn; the particle size of the oyster mushroom spawn powder is 20-100 mesh.

[0012] Since the mycelial chemical composition of different types of mushrooms is not the same, studies have shown that, without the addition of any chemical reagents, boards made from oyster mushroom substrate have stronger mechanical and waterproof properties compared to other oyster mushroom substrates (such as wood ear mushroom substrates, yellow elm mushroom substrates, and tea tree mushroom substrates). Therefore, oyster mushroom substrates are selected as the raw material for formaldehyde-free, energy-saving, and waterproof boards.

[0013] Preferably, the surfactant includes Tween 20.

[0014] The reason for using Tween 20 is that it can emulsify the aqueous solution of citric acid and epoxidized soybean oil, so that citric acid and epoxidized soybean oil are evenly dispersed in Tween 20. This makes it easier to ensure the uniform distribution of chemical reagents in the raw materials for preparing the board, thereby producing a board with uniform and stable mechanical and waterproof properties.

[0015] The second technical solution of the present invention provides a method for preparing the above-mentioned formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom substrate, comprising the following steps:

[0016] According to the prescribed dosage, the oyster mushroom stick powder, epoxidized soybean oil, citric acid, surfactant and water are mixed, and then hot-pressed and cooled to obtain the formaldehyde-free energy-saving waterproof board.

[0017] Preferably, the hot pressing temperature is 120–190°C, the pressure is 18–20 tons, and the time is 1 hour.

[0018] Preferably, the cooling method is air cooling; the cooling time is 1 hour.

[0019] Furthermore, the hot pressing is performed in a mold; the cooling process also includes a demolding step.

[0020] Preferably, the formaldehyde-free energy-saving waterproof board based on oyster mushroom spawn has an internal bond strength of 1.71–2.28 MPa, a static bending strength of 15.31–22.64 MPa, an elastic modulus of 2651.94–5580.3 MPa, a 2-hour water absorption thickness swelling rate of 3.80–6.60%, and a 24-hour water absorption thickness swelling rate of 19.83–33.44%.

[0021] The technical principle of this invention is as follows:

[0022] This invention, through the control of the raw materials and their dosage, as well as the preparation process, yields high-strength oyster mushroom substrate boards. The mechanical and waterproof properties of these boards are comparable to or superior to those of the national standard particleboard (GB / T 4897-2015), as detailed below:

[0023] First, under hot-pressing conditions, citric acid can effectively degrade the cellulose (containing hydroxyl groups) in the oyster mushroom substrate and undergo esterification and cross-linking reactions with the degraded cellulose; furthermore, under hot-pressing conditions, citric acid and epoxidized soybean oil can undergo cross-linking reactions to generate long-chain fatty acid esters; the network structure formed by the above cross-linking reactions can effectively improve the mechanical properties of the board.

[0024] Secondly, the esters generated during the hot pressing process are hydrophobic, which can effectively improve the waterproof performance of the board.

[0025] In addition, this invention improves the bonding efficiency of oyster mushroom substrate by adding citric acid and epoxidized soybean oil to the oyster mushroom stick powder and conducting an esterification and cross-linking reaction under hot pressing conditions. This ensures that substrates with excellent mechanical properties can be prepared with relatively low hot pressing and cooling times, solving the problems of high energy consumption and low production efficiency in substrate preparation caused by long hot pressing and cooling times in the prior art.

[0026] Finally, the entire board preparation process completely avoids the addition of chemical adhesives such as phenolic resin and urea-formaldehyde resin, ensuring that the prepared boards are environmentally friendly and formaldehyde-free.

[0027] The present invention discloses the following technical effects:

[0028] 1. In the preparation process of this invention, no chemical adhesives such as phenolic resin and urea-formaldehyde resin are added, and the resulting board is environmentally friendly and formaldehyde-free.

[0029] 2. The mechanical and waterproof properties of the high-strength oyster mushroom substrate obtained by this invention are comparable to or better than those of the national standard particleboard (GB / T 4897-2015), solving the problems of high energy consumption, low preparation efficiency and poor waterproof performance of formaldehyde-free oyster mushroom substrate, and thus having good economic benefits.

[0030] 3. The chemical additives used in this invention, epoxidized soybean oil and citric acid, are both biomass-derived materials, which are non-toxic, harmless, environmentally friendly, and low in cost. The biomass boards prepared by this method have a simple process flow, are easy to mass-produce, and have good commercial application prospects. Attached Figure Description

[0031] Figure 1 The infrared spectra of the sheet material obtained in Example 1 before and after hot pressing are shown below.

[0032] Figure 2 The infrared spectra of the sheet material obtained in Example 2 before and after hot pressing;

[0033] Figure 3 The infrared spectra of the sheet material obtained in Example 3 before and after hot pressing;

[0034] Figure 4 The infrared spectra of the sheet material obtained in Comparative Example 1 before and after hot pressing are shown.

[0035] Figure 5 The infrared spectra of the sheet material obtained in Comparative Example 2 before and after hot pressing are shown.

[0036] Figure 6 The infrared spectra of the sheet material obtained in Comparative Example 3 before and after hot pressing are shown.

[0037] Figure 7 The infrared spectra of the sheet material obtained in Comparative Example 4 before and after hot pressing are shown.

[0038] Figure 8 The infrared spectra of the sheet material obtained in Comparative Example 5 before and after hot pressing are shown.

[0039] Figure 9 The infrared spectra of the sheet material obtained in Comparative Example 6 before and after hot pressing are shown.

[0040] Figure 10 The infrared spectra of the sheet material obtained in Comparative Example 7 before and after hot pressing are shown.

[0041] Figure 11The infrared spectra of the sheet material obtained in Comparative Example 8 before and after hot pressing are shown.

[0042] Figure 12 The infrared spectra of the sheet material obtained in Comparative Example 9 before and after hot pressing are shown.

[0043] Figure 13 The infrared spectra of the sheet material obtained in Comparative Example 10 before and after hot pressing are shown.

[0044] Figure 14 The mechanical properties of the sheet material obtained in Example 1 at different hot-pressing temperatures are shown, where a is the internal bond strength (MPa), b is the static bending strength (MPa), and c is the modulus of elasticity (MPa). Detailed Implementation

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0047] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0048] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0049] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0050] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0051] Unless otherwise specified, all raw materials used in the following embodiments and comparative examples of this invention are commercially available products, and the source of these commercially available products does not affect the technical effect of this invention.

[0052] Unless otherwise specified, the room temperature involved in this invention is 25±5℃.

[0053] Example 1

[0054] This embodiment provides the preparation of the formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom spawn, and the specific steps are as follows:

[0055] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0056] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 120℃.

[0057] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0058] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.28 mm.

[0059] Example 2

[0060] This embodiment provides the preparation of the formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom spawn, and the specific steps are as follows:

[0061] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0062] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0063] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0064] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.71 mm.

[0065] Example 3

[0066] This embodiment provides the preparation of the formaldehyde-free, energy-saving, and waterproof board based on oyster mushroom spawn, and the specific steps are as follows:

[0067] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0068] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 180℃.

[0069] (3) Press the hot press to 18 tons and maintain constant temperature and pressure for 1 hour;

[0070] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.96 mm.

[0071] Comparative Example 1

[0072] The difference from Example 1 is that the addition of epoxidized soybean oil, citric acid and Tween 20 is omitted, while the rest is the same as in Example 1.

[0073] Specifically:

[0074] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0075] (2) Take 7 parts of deionized water according to the mass fraction, mix it evenly with the oyster mushroom stick powder obtained in step (1), and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 120℃.

[0076] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0077] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.59 mm.

[0078] Comparative Example 2

[0079] The difference from Example 2 is that the addition of epoxidized soybean oil, citric acid and Tween 20 is omitted, while the rest is the same as in Example 2.

[0080] Specifically:

[0081] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0082] (2) Take 7 parts of deionized water according to the mass fraction, mix it evenly with the oyster mushroom stick powder obtained in step (1), and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0083] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0084] (4) Turn off the power to the hot press and allow the board to cool naturally at room temperature for 1 hour. Then, demold the board and remove it. The thickness of the resulting board is 4.99 mm. (The board without added chemical reagents lacks the esterification and amidation crosslinking reactions described in the above examples, resulting in a relatively loose internal structure, lower density, and therefore a higher thickness.)

[0085] Comparative Example 3

[0086] The difference from Example 2 is that epoxidized soybean oil is omitted, while the rest is the same as in Example 2.

[0087] Specifically:

[0088] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0089] (2) Take 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0090] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0091] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.71 mm.

[0092] Comparative Example 4

[0093] The difference from Example 2 is that citric acid is omitted, otherwise it is the same as Example 2.

[0094] Specifically:

[0095] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0096] (2) Take 4 parts of epoxidized soybean oil and 4 parts of Tween 20 according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0097] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0098] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.03 mm.

[0099] Comparative Example 5

[0100] The difference between this comparative example and Example 2 is that the mass fraction of citric acid was increased; otherwise, it is the same as Example 2.

[0101] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0102] (2) Take 4 parts of epoxidized soybean oil, 3 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0103] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0104] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.61 mm.

[0105] Comparative Example 6

[0106] The difference between this comparative example and Example 2 is that the mass fraction of epoxidized soybean oil in the raw materials was increased; otherwise, it is the same as Example 1.

[0107] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0108] (2) Take 6 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0109] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0110] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.79 mm.

[0111] Comparative Example 7

[0112] The difference from Example 2 is that the hot pressing temperature is adjusted to 100°C, otherwise it is the same as Example 2.

[0113] Specifically:

[0114] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0115] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 100℃.

[0116] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 1 hour;

[0117] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.46 mm.

[0118] Comparative Example 8

[0119] The difference from Example 2 is that the hot pressing pressure is adjusted to 25 tons, otherwise it is the same as Example 2.

[0120] Specifically:

[0121] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0122] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0123] (3) Press the hot press to 25 tons and maintain constant temperature and pressure for 1 hour;

[0124] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 4.85 mm.

[0125] Comparative Example 9

[0126] The difference from Example 2 is that the hot pressing pressure is adjusted to 12 tons, otherwise it is the same as Example 2.

[0127] Specifically:

[0128] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0129] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0130] (3) Press the hot press to 12 tons and maintain constant temperature and pressure for 1 hour;

[0131] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.64 mm.

[0132] Comparative Example 10

[0133] The difference from Example 2 is that the hot pressing time is adjusted to 0.5h, while the rest is the same as Example 2.

[0134] (1) Powder the oyster mushroom sticks and dry them to constant weight to obtain oyster mushroom stick powder (100 mesh), and take 63 portions of oyster mushroom stick powder.

[0135] (2) Take 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water according to the mass ratio and stir them evenly to obtain a mixture. Mix the mixture evenly with the oyster mushroom stick powder obtained in step (1) and spread it in the square mold (10cm×10cm) of the hot press (Xinnuo RYJ-600D1S) and heat it to 190℃.

[0136] (3) Press the hot press to 20 tons and maintain constant temperature and pressure for 0.5 hours;

[0137] (4) Turn off the power of the hot press and let the board cool naturally at room temperature for 1 hour. Then demold the board and take it out. The thickness of the board is 5.10 mm.

[0138] Performance testing:

[0139] 1. The mechanical properties of the boards obtained in Examples 1-3 and Comparative Examples 1-10 were determined according to the national standard (GB / T4897-2015), and the results are shown in Table 1.

[0140] Table 1. Test results of mechanical properties of the sheet metal

[0141]

[0142] As shown in Table 1, compared with formaldehyde-free boards without any chemical additives (Comparative Example 1, Comparative Example 2), formaldehyde-free boards with only citric acid added (Comparative Example 3), and formaldehyde-free boards with only epoxidized soybean oil added (Comparative Example 4), the formaldehyde-free energy-saving and waterproof boards for oyster mushroom substrate of the present invention have significantly improved waterproof performance, and can achieve application performance that is significantly better than the national standard (GB / T4897-2015).

[0143] The mass ratio of citric acid and epoxidized soybean oil required for preparing the formaldehyde-free energy-saving and waterproof board of the present invention should be controlled at about 1:2. Significant deviation from this mass ratio will reduce the mechanical properties and waterproof performance of the board.

[0144] The hot-pressing temperature required to prepare the formaldehyde-free energy-saving and waterproof board of the present invention can be set to 120℃ or 190℃. The mechanical properties and waterproof properties of the board prepared at 120℃ are superior to those of furniture-type particleboard used under dry conditions; the mechanical properties and waterproof properties of the board prepared at 190℃ are superior to those of load-bearing particleboard used under dry conditions.

[0145] The pressure required to prepare the formaldehyde-free, energy-saving, and waterproof board described in this invention can be set within the range of 18 to 20 tons. Too low a pressure results in a loose internal structure and deterioration of the board's mechanical properties; too high a pressure damages the internal fiber structure, weakening the mechanical interlocking effect between fibers and further deteriorating the board's mechanical properties.

[0146] The hot-pressing time required to prepare the formaldehyde-free, energy-saving, and waterproof board described in this invention should be controlled to around 1 hour. Too short a hot-pressing time is detrimental to the bonding reaction of the board.

[0147] 2. Figures 1-13 The infrared spectra of the plates described in Examples 1-3 and Comparative Examples 1-10 before and after hot pressing are shown in sequence.

[0148] Infrared spectra of the sheet material described in Example 1 before and after hot pressing, 2926.4 cm⁻¹ -1 and 2856.6cm -1 The asymmetric stretching vibration mode of the methylene group in the epoxidized soybean oil in the board material is shown in Example 1 at 828.4 cm after hot pressing. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil completely disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid, located at 1735.4 cm⁻¹. -1 The significantly enhanced intensity of the C=O vibration mode indicates that esters were generated in Example 1 after hot pressing. Both of these reactions effectively improved the mechanical properties of Example 1. Furthermore, the formation of esters after hot pressing effectively enhanced the waterproof performance of the board.

[0149] As can be seen from the infrared spectra of the sheet material described in Example 2 before and after hot pressing, compared to before hot pressing, the position of the sheet material in Example 2 after hot pressing is 1731.8 cm⁻¹. -1 (1733.1cm -1 The intensity of the C=O vibration mode of Example 2 was significantly enhanced, indicating that ester substances were generated after hot pressing. Therefore, Example 2 has improved waterproof performance compared to Comparative Example 2. Furthermore, 827.1 cm -1 (826.8cm -1 The vibrational modes of the epoxy groups in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing. Both the esterification crosslinking reaction and the ring-opening crosslinking reaction of the epoxidized soybean oil can effectively enhance the mechanical properties of the board.

[0150] As can be seen from the infrared spectra of the sheet material described in Example 3 before and after hot pressing, compared to before hot pressing, the infrared spectrum of Example 3 after hot pressing is 828.4 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil completely disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing; located at 1735.5 cm -1 The intensity of the C=O vibration mode was significantly enhanced, indicating that esters were generated after hot pressing in Example 3. Both of the above reactions can effectively enhance the mechanical properties of the sheet material. ， Meanwhile, the formation of esters effectively improved the waterproof performance of the board material in Example 3.

[0151] Infrared spectra of the sheet material described in Comparative Example 1 before and after hot pressing are shown. Comparative Example 1 exhibits an infrared spectrum located at 1742 cm⁻¹ after hot pressing. -1The carbonyl vibration mode indicates that esters were generated inside the board of Comparative Example 1 after hot pressing, which can be attributed to the self-gluing of lignocellulose in the oyster mushroom substrate. Although infrared data showed that esters were generated in Comparative Example 1 after hot pressing, its mechanical and waterproof properties did not meet the national standards (Table 1). By comparing its mechanical and waterproof properties with those of Example 1, it can be found that adding epoxidized soybean oil and citric acid during the preparation of the energy-saving and waterproof board based on oyster mushroom substrate can effectively improve the mechanical and waterproof properties of the board.

[0152] The infrared spectra of the sheet material described in Comparative Example 2 before and after hot pressing show that Comparative Example 2 did not exhibit any infrared spectra located between 1730 and 1740 cm⁻¹ after hot pressing. -1 The nearby carbonyl vibrational modes indicate that no esters were generated inside the board of Comparative Example 2 after hot pressing. The only difference in the preparation methods of the boards in Comparative Example 1 (120°C) and Comparative Example 2 (190°C) is the hot pressing temperature. Therefore, the absence of esters generated inside the board after hot pressing in Comparative Example 2 can be attributed to the excessively high hot pressing temperature, which is detrimental to the self-gluing of lignocellulose inside the oyster mushroom substrate. In contrast, the energy-saving and waterproof board based on oyster mushroom substrate in Example 2 incorporates epoxidized soybean oil and citric acid during its preparation, which effectively enhances the self-gluing properties of the board. Therefore, the mechanical and waterproof properties of Example 2 meet the national standards for load-bearing particleboard used under dry conditions (Table 1).

[0153] The infrared spectra of the sheet material described in Comparative Example 3 before and after hot pressing are shown. The sheet material in Comparative Example 3 is located at 1735.4 cm⁻¹ after hot pressing. -1 The carbonyl vibration mode was significantly enhanced, indicating that esters were generated inside the board of Comparative Example 3 after hot pressing. This can be attributed to the lignocellulose in the oyster mushroom substrate and the self-gluing effect of cellulose and citric acid. As shown in Table 1, its mechanical properties and water resistance are significantly improved compared to Comparative Example 2, indicating that citric acid can effectively improve the self-gluing ability of the board. However, its mechanical properties and water resistance still do not meet the national standards, indicating that the simultaneous addition of epoxidized soybean oil and citric acid plays an important role in the self-gluing of the board during the preparation of the energy-saving and waterproof board based on oyster mushroom substrate.

[0154] The infrared spectra of the sheet material described in Comparative Example 4 before and after hot pressing are shown. The sheet material in Comparative Example 4 is located at 1735.0 cm⁻¹ after hot pressing. -1 The intensity of the C=O vibrational mode did not show an increasing trend, indicating that Comparative Example 4 had a lower content of esters after hot pressing. This is because citric acid was not added during the preparation of Comparative Example 4, resulting in a lower content of cross-linking esters generated under hot pressing conditions. Furthermore, the vibrational mode of the epoxy groups in epoxidized soybean oil (825.9 cm⁻¹) showed no increasing trend. -1The vibration intensity decreased but still existed after hot pressing, indicating that some of the epoxy groups in the epoxidized soybean oil underwent a ring-opening cross-linking reaction with the lignocellulose in the oyster mushroom substrate. Compared with the oyster mushroom substrate board without added epoxidized soybean oil and citric acid reagent (Comparative Example 2), Comparative Example 4 showed improved mechanical properties to some extent due to the addition of epoxidized soybean oil. However, since citric acid was not added in Comparative Example 4, the ring-opening reaction between citric acid and epoxidized soybean oil, as well as the esterification cross-linking reaction between citric acid and the lignocellulose in the oyster mushroom substrate, were lacking. Therefore, compared with Examples 1-3, the mechanical properties and water resistance of Comparative Example 4 were worse.

[0155] Infrared spectra of the sheet material described in Comparative Example 5 before and after hot pressing are shown at 825.9 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil showed a significant decrease or even complete disappearance in intensity after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening cross-linking reaction with citric acid after hot pressing, which enhanced the mechanical properties of the board to some extent. However, Comparative Example 5 showed a value of 1735.4 cm after hot pressing. -1 The intensity of the C=O vibration mode did not show an increasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 5 did not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 5 were worse. This may be related to the fact that excessive citric acid content would inhibit the formation of ester substances in the board.

[0156] Infrared spectra of the sheet material described in Comparative Example 6 before and after hot pressing are shown at 828.4 cm⁻¹. -1 The vibrational modes of the epoxy groups in the epoxidized soybean oil weakened but did not disappear after hot pressing, indicating that some of the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing, and unreacted epoxidized soybean oil still existed in the hot-pressed sheet. Comparative Example 6 was located at 1736.3 cm after hot pressing. -1 The intensity of the C=O vibration mode did not show an increasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 6 did not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 6 were worse. This may be related to the fact that excessive epoxidized soybean oil content would inhibit the formation of ester substances in the board.

[0157] Infrared spectra of the sheet material described in Comparative Example 7 before and after hot pressing are shown at 828.4 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing. Comparative Example 7 showed a crosslinking mode at 1736.3 cm⁻¹ after hot pressing. -1The intensity of the C=O vibration mode did not show an increasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 7 did not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 7 are worse. This is related to the fact that the hot pressing temperature of Comparative Example 7 was too low during the preparation process, which is not conducive to the formation of ester substances in the board.

[0158] Infrared spectra of the sheet material described in Comparative Example 8 before and after hot pressing are shown at 828.5 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing. Comparative Example 8 was located at 1744.5 cm⁻¹ after hot pressing. -1 The intensity of the C=O vibration mode showed a significant increasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 8 increased significantly. However, compared with Examples 1-3, the mechanical and waterproof properties of Comparative Example 8 were worse, which is related to the excessively high hot pressing pressure during the preparation process. Specifically, excessively high hot pressing pressure leads to greater internal stress in the board, making it more prone to cracking from the core layer during cooling and demolding. Excessively high hot pressing pressure also damages the natural structure of the woody fibers in the oyster mushroom substrate, especially the integrity of long fibers, thereby causing a decrease in the mechanical properties of the board.

[0159] Infrared spectra of the sheet material described in Comparative Example 9 before and after hot pressing are shown at 828.5 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing. Comparative Example 9 was located at 1739.5 cm⁻¹ after hot pressing. -1 The intensity of the C=O vibration mode showed a significant decreasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 9 was very low. Therefore, compared with Examples 1-3, Comparative Example 9 had poorer mechanical and waterproof properties, which is related to the excessively low hot pressing pressure during the preparation of Comparative Example 9. Specifically, excessively low hot pressing pressure is not conducive to the self-gluing of lignocellulose in the oyster mushroom substrate, the esterification reactions between citric acid and oyster mushroom substrate cellulose, and the esterification reactions between citric acid and epoxidized soybean oil.

[0160] Infrared spectra of the sheet material described in Comparative Example 10 before and after hot pressing are shown at 828.4 cm⁻¹. -1 The vibrational modes of the epoxy groups in epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing. Comparative Example 10 showed a crosslinking mode at 1735.4 cm⁻¹ after hot pressing. -1The intensity of the C=O vibration mode showed a significant decreasing trend, indicating that the content of ester substances generated after hot pressing in Comparative Example 10 was very low. Therefore, compared with Examples 1-3, Comparative Example 10 had poorer mechanical and waterproof properties, which is related to the excessively short hot pressing time during the preparation process of Comparative Example 10. Specifically, an excessively short hot pressing time is not conducive to the esterification reaction between citric acid and cellulose from the oyster mushroom substrate, and between citric acid and epoxidized soybean oil inside the board.

[0161] 3. Under hot-pressing conditions, temperature affects the mechanical properties of the sheet material. The mechanical properties of the sheet material obtained in Example 1 were tested under different hot-pressing temperatures, and the results are as follows: Figure 14 As shown.

[0162] Figure 14 The mechanical properties of oyster mushroom substrate blocks prepared under different hot-pressing temperatures are shown. For example... Figure 14 As shown, the mechanical properties of the board reach a maximum at 120℃, mainly because 120℃ is the optimal temperature for the esterification reaction of citric acid and cellulose. With further increases in temperature, the mechanical properties of the board reach their maximum values ​​between 180 and 190℃, primarily due to this temperature range being the optimal temperature for the esterification reaction of citric acid and epoxidized soybean oil.

[0163] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0164] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A formaldehyde-free energy-saving waterproof panel based on Pleurotus ostreatus mushroom sticks, characterized in that, The preparation raw materials include the following mass fractions: 60-65 parts of Pleurotus ostreatus stick powder, 4 parts of epoxy soybean oil, 2 parts of citric acid, 4-6 parts of surfactant and 5-8 parts of water.

2. The non-formaldehyde energy-saving waterproof plate based on the Pleurotus ostreatus mushroom stick according to claim 1, characterized in that, The Pleurotus ostreatus stick powder is obtained by grinding and sieving Pleurotus ostreatus sticks; the particle size of the Pleurotus ostreatus stick powder is 20-100 mesh.

3. The non-formaldehyde energy-saving waterproof plate based on the Pleurotus ostreatus mushroom stick according to claim 1, characterized in that, The surfactant is Tween 20.

4. The non-formaldehyde energy-saving waterproof plate based on the Pleurotus ostreatus mushroom stick according to claim 1, characterized in that, The internal bonding strength of the formaldehyde-free energy-saving waterproof board based on Pleurotus ostreatus stick is 1.71-2.28 MPa, the static bending strength is 15.31-22.64 MPa, the elastic modulus is 2651.94-5580.3 MPa, the 2h water absorption thickness expansion rate is 3.80-6.60%, and the 24h water absorption thickness expansion rate is 19.83-33.44%.

5. The method for preparing the non-formaldehyde energy-saving waterproof plate based on the Pleurotus ostreatus stick according to any one of claims 1-4, characterized in that, The method comprises the following steps: According to the specified amount, the Pleurotus ostreatus stick powder, epoxy soybean oil, citric acid, surfactant and water are uniformly mixed, and then hot-pressed and cooled to obtain the formaldehyde-free energy-saving waterproof board. The temperature of the hot-pressing is 120-190℃, the pressure is 18-20 tons, and the time is 1h.

6. The production method according to claim 5, wherein The cooling mode is air cooling; the cooling time is 1h.

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