Formaldehyde-free energy-saving waterproof board based on oyster mushroom sticks

Abstract

The invention discloses a formaldehyde-free energy-saving waterproof board based on oyster mushroom sticks, and belongs to the technical field of agricultural solid waste resource utilization. The aldehyde-free energy-saving waterproof board based on the oyster mushroom sticks is prepared from the following raw materials in parts by mass: 60-65 parts of oyster mushroom stick powder, 4-6 parts of epoxidized soybean oil, 2-3 parts of citric acid, 4-6 parts of a surfactant and 5-8 parts of water. The invention further provides a preparation method of the aldehyde-free energy-saving waterproof board based on the oyster mushroom sticks. The mechanical property index of the obtained high-strength oyster mushroom stick board can reach equivalent or better application performance of a national standard shaving board (GB / T 4897-2015), the problems that a formaldehyde-free oyster mushroom stick board is high in hot-pressing energy consumption, low in preparation efficiency and poor in waterproof performance are solved, and good economic benefits are achieved. The biomass plate prepared by the method is simple in process flow and easy for large-scale production, and has a good commercial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural solid waste resource utilization, and more specifically relates to a formaldehyde-free energy-saving and waterproof board based on oyster mushroom sticks. Background Art

[0002] As people's living standards improve, edible mushroom production increases year by year, and the resulting amount of mushroom spawn waste is also on the rise. Currently, the main methods for processing collected mushroom spawn resources are composting, biomass energy conversion, animal feed production, and bio-based material manufacturing. However, these methods only consume a small portion of the mushroom spawn, while the vast majority are simply landfilled or incinerated, wasting biomass resources and causing serious pollution to the water, soil, and atmospheric environments. How to effectively process mushroom spawn, conserve resources and energy, protect the ecological environment, and improve agricultural industry efficiency is of great significance for promoting the development of low-carbon agriculture and addressing climate change.

[0003] Mushroom spawn is mainly composed of sawdust, cottonseed hulls, straw, etc., which are rich in lignin, cellulose and hemicellulose, and have a chemical composition similar to that of wood. Therefore, mushroom spawn is a high-quality raw material for the preparation of non-wood boards. However, the current preparation of boards based on mushroom spawn has the following problems:

[0004] (1) The hot pressing process consumes a lot of energy and has low production efficiency. At present, the hot pressing method is mainly used to prepare biomass boards. For example, the prior art discloses a method for preparing formaldehyde-free composite boards using corn stalks and mushroom sticks. The hot pressing temperature required for board preparation is 190°C, 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 high, and the production efficiency is low. Therefore, the development of energy-saving and efficient board preparation technology based on mushroom sticks is of great significance to the development of the biomass board research field.

[0005] (2) Poor waterproof performance. Although the mycelium layer in the mushroom spawn has certain waterproof performance, due to the influence of the many hydrophilic hydroxyl functional groups contained in the mushroom spawn, the waterproof performance of the board prepared with the untreated mushroom spawn as raw material is poor, and it is difficult to meet the indicators required by the national standard. Therefore, further improving the waterproof performance of the board based on the mushroom spawn is a hot problem in the current research field of biomass board. Summary of the Invention

[0006] Different types of mushroom mycelium contain significant variations in chemical composition. Research has found that, without the addition of any additional chemical reagents, boards produced using Pleurotus ostreatus logs via hot pressing exhibit superior mechanical properties compared to boards made from other mushroom logs. Therefore, the present invention aims to provide a novel formaldehyde-free, energy-saving, and waterproof board based on Pleurotus ostreatus logs, addressing the aforementioned issues of the prior art and enabling the production of energy-efficient, highly efficient, and waterproof formaldehyde-free composite boards using Pleurotus ostreatus log waste.

[0007] To achieve the above object, the present invention provides the following solutions:

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

[0009] 60-65 parts of oyster mushroom stick 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 for its environmental friendliness, low toxicity, renewability, and low cost. Citric acid was chosen for the following reasons: 1. As a tribasic acid, compared to dibasic and monobasic acids, citric acid undergoes esterification with hydroxyl groups under hot pressing to form a more complex crosslinked network, effectively improving the mechanical properties of the sheet; 2. Compared to other polycarboxylic acids, it has better water solubility, which facilitates its uniform dispersion in surfactants.

[0011] Preferably, the oyster mushroom stick powder is obtained by grinding and sieving oyster mushroom sticks; the particle size of the oyster mushroom stick powder is 20 to 100 meshes.

[0012] Since the chemical composition of mycelium in different types of mushrooms is different, studies have shown that without adding any chemical reagents, compared with other oyster mushroom sticks (hair ear mushroom sticks, elm yellow mushroom sticks, tea tree mushroom sticks, etc.), the mechanical properties and waterproof properties of the boards prepared with oyster mushroom sticks are stronger. Therefore, oyster mushroom sticks are selected as the raw material for formaldehyde-free energy-saving waterproof boards.

[0013] Preferably, the surfactant comprises Tween 20.

[0014] The reason for using Tween 20 is that Tween 20 can emulsify the aqueous solution of citric acid and epoxidized soybean oil, so that the citric acid and epoxidized soybean oil are evenly dispersed in Tween 20, which is convenient for ensuring the uniform distribution of chemical reagents in the raw materials for preparing the board, and then preparing boards with uniform and stable mechanical properties and waterproof properties.

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

[0016] The oyster mushroom stick powder, epoxy soybean oil, citric acid, surfactant and water are mixed according to the prescribed amount, and then hot-pressed and cooled to obtain the formaldehyde-free energy-saving and 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; and the cooling time is 1 hour.

[0019] Furthermore, the hot pressing is carried out in a mold; and after the cooling, a demoulding step is also included.

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

[0021] The technical principles of the present invention are as follows:

[0022] The present invention prepares a high-strength oyster mushroom stick board by regulating the raw materials, dosage, and preparation process for the board. The mechanical properties and waterproof performance indicators of the board can reach or exceed the application performance of the national standard particleboard (GB / T 4897-2015), as follows:

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

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

[0025] In addition, the present invention adds two chemical reagents, citric acid and epoxidized soybean oil, to the oyster mushroom stick powder, and an esterification cross-linking reaction occurs under hot pressing conditions, thereby effectively improving the gluing efficiency of the oyster mushroom stick board, ensuring that the board with excellent mechanical properties can be prepared within a relatively short hot pressing time and cooling time, thereby solving the problems of high energy consumption and low production efficiency in the prior art caused by the long hot pressing and cooling time.

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

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

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

[0029] 2. The mechanical properties and waterproof performance indicators of the high-strength oyster mushroom stick board obtained by the present invention can reach the application performance equivalent to or better than the national standard particleboard (GB / T 4897-2015), solving the problems of high hot pressing energy consumption, low preparation efficiency and poor waterproof performance of formaldehyde-free oyster mushroom stick board, and having good economic benefits.

[0030] 3. The chemical additives epoxidized soybean oil and citric acid used in the present invention are biomass-derived materials, which are non-toxic, harmless, environmentally friendly and low-cost. The biomass board prepared by this method has a simple process flow, is easy to mass produce, and has good commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 IR spectra of the plate obtained in Example 1 before and after hot pressing;

[0032] Figure 2 This is the infrared spectrum of the plate obtained in Example 2 before and after hot pressing;

[0033] Figure 3 IR spectra of the plate obtained in Example 3 before and after hot pressing;

[0034] Figure 4 IR spectra of the plate obtained in Comparative Example 1 before and after hot pressing;

[0035] Figure 5 IR spectra of the plate obtained in Comparative Example 2 before and after hot pressing;

[0036] Figure 6 IR spectra of the plate obtained in Comparative Example 3 before and after hot pressing;

[0037] Figure 7 The infrared spectra of the plate obtained in Comparative Example 4 before and after hot pressing;

[0038] Figure 8 IR spectra of the plate obtained in Comparative Example 5 before and after hot pressing;

[0039] Figure 9 IR spectra of the plate obtained in Comparative Example 6 before and after hot pressing;

[0040] Figure 10 IR spectra of the plate obtained in Comparative Example 7 before and after hot pressing;

[0041] Figure 11IR spectra of the plate obtained in Comparative Example 8 before and after hot pressing;

[0042] Figure 12 IR spectra of the plate obtained in Comparative Example 9 before and after hot pressing;

[0043] Figure 13 IR spectra of the plate obtained in Comparative Example 10 before and after hot pressing;

[0044] Figure 14 The mechanical properties of the plate obtained in Example 1 at different hot pressing temperatures, where a is the internal bonding strength (MPa), b is the static bending strength (MPa), and c is the elastic modulus (MPa). DETAILED DESCRIPTION

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting 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 terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0047] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0048] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

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

[0050] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0051] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are all commercially available products, and the sources of the commercially available products do not affect the technical effects of the present invention.

[0052] Unless otherwise specified, the room temperature referred to in the present invention is 25±5°C.

[0053] Example 1

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

[0055] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0056] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom stick powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 120°C;

[0057] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, remove the plate from the mold. The thickness of the obtained plate is 5.28 mm.

[0059] Example 2

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

[0061] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0062] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0063] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate is 4.71 mm.

[0065] Example 3

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

[0067] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0068] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom stick powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 180°C;

[0069] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate 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, and the rest is the same as Example 1.

[0073] Specifically:

[0074] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0075] (2) taking 7 parts by mass of deionized water, mixing it evenly with the oyster mushroom stick powder obtained in step (1), and paving it in a square mold (10 cm × 10 cm) of a hot press (Xinnuo RYJ-600D1S), and heating it to 120°C;

[0076] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate 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, and the rest is the same as Example 2.

[0080] Specifically:

[0081] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0082] (2) taking 7 parts by mass of deionized water, mixing it with the oyster mushroom stick powder obtained in step (1), and paving it in a square mold (10 cm × 10 cm) of a hot press (Xinnuo RYJ-600D1S), and heating it to 190°C;

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

[0084] (4) The hot press was turned off and the sheet was allowed to cool naturally at room temperature for 1 hour. The sheet was then demolded and removed. The resulting sheet had a thickness of 4.99 mm. (The sheet without chemical reagents lacked the esterification and amidation cross-linking reactions described in the above examples, resulting in a relatively loose internal structure and lower density, and therefore a higher thickness.)

[0085] Comparative Example 3

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

[0087] Specifically:

[0088] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0089] (2) taking 2 parts by mass of citric acid, 4 parts of Tween 20 and 7 parts of deionized water and stirring them evenly to obtain a mixture, mixing the mixture evenly with the oyster mushroom powder obtained in step (1), and paving the mixture in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heating it to 190°C;

[0090] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate is 4.71 mm.

[0092] Comparative Example 4

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

[0094] Specifically:

[0095] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0096] (2) 4 parts by mass of epoxidized soybean oil and 4 parts of Tween 20 were mixed to obtain a mixture, the mixture was mixed evenly with the oyster mushroom stick powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0097] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate 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 is increased, and the rest is the same as Example 2.

[0101] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0102] (2) 4 parts of epoxidized soybean oil, 3 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom stick powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0103] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate 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 material is increased, and the other parts are the same as Example 1.

[0107] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0108] (2) 6 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom stick powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0109] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, remove the plate from the mold. The thickness of the obtained plate 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., and the rest is the same as Example 2.

[0113] Specifically:

[0114] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0115] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 100°C;

[0116] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate 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, and the rest is the same as Example 2.

[0120] Specifically:

[0121] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0122] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0123] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, remove the plate from the mold. The thickness of the obtained plate 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, and the rest is the same as Example 2.

[0127] Specifically:

[0128] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0129] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0130] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate is 5.64 mm.

[0132] Comparative Example 10

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

[0134] (1) Pleurotus ostreatus mushroom sticks were crushed and dried to constant weight to obtain pleurotus ostreatus mushroom stick powder (100 mesh), and 63 parts of pleurotus ostreatus mushroom stick powder were taken.

[0135] (2) 4 parts of epoxidized soybean oil, 2 parts of citric acid, 4 parts of Tween 20 and 7 parts of deionized water were mixed uniformly to obtain a mixture, and the mixture was mixed uniformly with the oyster mushroom powder obtained in step (1), and the mixture was spread in a square mold (10 cm × 10 cm) of a hot press (Sinno RYJ-600D1S), and heated to 190°C;

[0136] (3) Pressurize 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 allow the plate to cool naturally at room temperature for 1 hour. Then, the plate is demoulded and taken out. The thickness of the obtained plate is 5.10 mm.

[0138] Performance testing:

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

[0140] Table 1 Mechanical properties test results of the plate

[0141]

[0142] As can be seen from Table 1, compared with the formaldehyde-free boards without adding any chemical additives (Comparative Example 1, Comparative Example 2), the formaldehyde-free boards with only citric acid added (Comparative Example 3), and the formaldehyde-free boards with only epoxy soybean oil added (Comparative Example 4), the waterproof performance of the formaldehyde-free energy-saving waterproof boards made of oyster mushroom sticks of the present invention is significantly improved, 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 waterproof sheet of the present invention should be controlled at about 1:2. A significant deviation from this mass ratio will reduce the mechanical properties and waterproof properties of the sheet.

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

[0145] The pressure required to produce the formaldehyde-free, energy-saving, and waterproof sheet of the present invention can be set within a range of 18 to 20 tons. Too low a pressure results in a loose internal structure of the sheet, deteriorating the sheet's mechanical properties. Too high a pressure destroys the sheet's internal fiber structure, weakening the mechanical interlocking effect between the fibers and deteriorating the sheet's mechanical properties.

[0146] The hot pressing time required to prepare the formaldehyde-free energy-saving and waterproof sheet material of the present invention should be controlled to about 1 hour. Too short a hot pressing time is not conducive to the bonding reaction of the sheet material.

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

[0148] The infrared spectrum of the plate in Example 1 before and after hot pressing shows that 2926.4cm -1 and 2856.6cm -1 is the asymmetric stretching vibration mode of the methylene group in the epoxidized soybean oil in the plate. In Example 1, the stretching vibration mode is located at 828.4 cm after hot pressing. -1 The vibration mode of the epoxy group in the epoxidized soybean oil completely disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening cross-linking reaction. -1 The C=O vibration mode intensity is significantly enhanced, indicating that ester substances are generated after hot pressing in Example 1. The above two types of reactions effectively improve the mechanical properties of Example 1. In addition, the generation of ester substances after hot pressing effectively enhances the waterproof performance of the board.

[0149] It can be seen from the infrared spectra of the plate of Example 2 before and after hot pressing that compared with that before hot pressing, the infrared spectrum of Example 2 after hot pressing is at 1731.8cm -1 (1733.1cm -1 ) of the C=O vibration mode intensity is significantly enhanced, indicating that ester substances are generated in Example 2 after hot pressing, so the waterproof performance of Example 2 is improved compared with that of Comparative Example 2. In addition, 827.1cm -1 (826.8cm -1 ) and the vibration mode of the epoxy group in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxidized soybean oil underwent a ring-opening cross-linking reaction with citric acid after hot pressing. The above-mentioned esterification cross-linking reaction and the ring-opening cross-linking reaction of the epoxidized soybean oil can effectively enhance the mechanical properties of the board.

[0150] It can be seen from the infrared spectra of the plate of Example 3 before and after hot pressing that compared with that before hot pressing, the infrared spectrum of Example 3 after hot pressing is at 828.4 cm -1 The vibration mode of the epoxy group in the epoxidized soybean oil completely disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening cross-linking reaction after hot pressing; -1 The intensity of the C=O vibration mode is significantly enhanced, indicating that ester substances are generated in Example 3 after hot pressing. The above two reactions can effectively enhance the mechanical properties of the board. At the same time, the generation of ester substances effectively improves the waterproof performance of the board of Example 3.

[0151] The infrared spectrum of the plate of Comparative Example 1 before and after hot pressing shows that after hot pressing, the plate of Comparative Example 1 has a peak at 1742 cm -1The carbonyl vibration mode of the carbonyl group in Comparative Example 1 indicates that esters are generated within the board after hot pressing, which can be attributed to the self-bonding of lignocellulose within the Pleurotus ostreatus mushroom sticks. Although infrared data show that esters are generated in Comparative Example 1 after hot pressing, its mechanical and waterproof properties do not meet national standards (Table 1). By comparing its mechanical and waterproof properties with those of Example 1, it can be found that the addition of epoxidized soybean oil and citric acid during the preparation of energy-saving and waterproof boards based on Pleurotus ostreatus mushroom sticks can effectively improve the mechanical and waterproof properties of the boards.

[0152] The infrared spectrum of the plate of Comparative Example 2 before and after hot pressing shows that the plate of Comparative Example 2 does not appear at 1730-1740 cm after hot pressing. -1 The carbonyl vibration mode near the surface of the plate indicates that no ester substances are generated inside the board of Comparative Example 2 after hot pressing. The only difference in the preparation method of the boards in Comparative Example 1 (120°C) and Comparative Example 2 (190°C) is the hot pressing temperature of the boards. Therefore, the fact that no ester substances are generated inside Comparative Example 2 after hot pressing can be attributed to the fact that the hot pressing temperature of the board is too high, which is not conducive to the self-adhesion of the wood cellulose inside the oyster mushroom sticks. In contrast, in the preparation process of the energy-saving and waterproof board based on oyster mushroom sticks in Example 2, two chemical reagents, epoxy soybean oil and citric acid, were added, which can effectively enhance the self-adhesion of the board. Therefore, the mechanical properties and waterproof properties of Example 2 both meet the national standards for load-bearing particleboards used under dry conditions (Table 1).

[0153] The infrared spectrum of the plate of Comparative Example 3 before and after hot pressing shows that the infrared spectrum of Comparative Example 3 is located at 1735.4 cm -1 The carbonyl vibration mode of the α-hydroxy-1, α-hydroxy-2-methyl-1-pyrrolidone (α-hydroxy-1-pyrrolidone) was significantly enhanced, indicating that esters were generated within the board of Comparative Example 3 after hot pressing. This can be attributed to the lignocellulose within the Pleurotus ostreatus mushroom sticks and the self-adhesion between cellulose and citric acid. As shown in Table 1, the mechanical properties and water resistance of the board were significantly improved compared to those of Comparative Example 2, indicating that citric acid can effectively enhance the self-adhesion ability of the board. However, the mechanical and water resistance still did not meet the national standards, indicating that the simultaneous addition of epoxidized soybean oil and citric acid during the preparation of energy-saving and waterproof boards based on Pleurotus ostreatus mushroom sticks played a significant role in the self-adhesion of the boards.

[0154] The infrared spectrum of the plate of Comparative Example 4 before and after hot pressing shows that the infrared spectrum of Comparative Example 4 is located at 1735.0 cm -1 The C=O vibration mode intensity does not show an increasing trend, indicating that the content of ester substances generated in Comparative Example 4 after hot pressing is relatively low. This is because no citric acid was added when preparing Comparative Example 4, and the content of ester substances that play a cross-linking role in the board under hot pressing conditions is relatively low. In addition, the vibration mode of the epoxy group in the epoxidized soybean oil (825.9 cm -1) After hot pressing, the vibration intensity weakened but still existed, indicating that some of the epoxy groups in the epoxidized soybean oil underwent a ring-opening crosslinking reaction with the lignocellulose in the oyster mushroom sticks. Compared with the oyster mushroom stick board (Comparative Example 2) to which no epoxidized soybean oil and citric acid reagent were added, the mechanical properties of the board were improved to a certain extent by the addition of epoxidized soybean oil in Comparative Example 4. However, since citric acid was not added in Comparative Example 4, the ring-opening reaction between citric acid and epoxidized soybean oil and the esterification crosslinking reaction between citric acid and lignocellulose in the oyster mushroom sticks were missing. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 4 were poor.

[0155] The infrared spectrum of the plate in Comparative Example 5 before and after hot pressing shows that the infrared spectrum at 825.9 cm -1 The vibration mode of the epoxy group in the epoxidized soybean oil was significantly weakened or even disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening cross-linking reaction after hot pressing, which enhanced the mechanical properties of the board to a certain extent. -1 There is no increasing trend in the intensity of the C=O vibration mode, indicating that the content of ester substances generated in Comparative Example 5 after hot pressing does not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 5 are poor, which may be related to the fact that excessive citric acid content inhibits the formation of ester substances in the board.

[0156] The infrared spectrum of the plate in Comparative Example 6 before and after hot pressing showed that the -1 The vibration mode of the epoxy group in the epoxidized soybean oil weakened in intensity after hot pressing but did not disappear, indicating that some of the epoxidized soybean oil underwent a ring-opening crosslinking reaction with citric acid after hot pressing, and some epoxidized soybean oil that did not participate in the ring-opening reaction still existed in the hot-pressed board. -1 There is no increasing trend in the intensity of the C=O vibration mode, indicating that the content of ester substances generated in Comparative Example 6 after hot pressing does not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 6 are poor, which may be related to the fact that the excessive epoxy soybean oil content inhibits the formation of ester substances in the board.

[0157] The infrared spectrum of the plate in Comparative Example 7 before and after hot pressing showed that the -1 The vibration mode of the epoxy group in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening crosslinking reaction after hot pressing. -1There is no increasing trend in the intensity of the C=O vibration mode, indicating that the content of ester substances generated in Comparative Example 7 after hot pressing does not increase significantly. Therefore, compared with Examples 1 to 3, the mechanical properties and waterproof properties of Comparative Example 7 are poor. This is related to the fact that the hot pressing temperature in the preparation process of Comparative Example 7 is too low, which is not conducive to the formation of ester substances in the board.

[0158] The infrared spectrum of the plate in Comparative Example 8 before and after hot pressing showed that the -1 The vibration mode of the epoxy group in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening crosslinking reaction after hot pressing. -1 The C=O vibration mode intensity of Comparative Example 8 shows a clear trend of increasing, indicating that the content of ester substances generated after hot pressing is significantly increased. However, compared with Examples 1-3, the mechanical properties and water resistance of Comparative Example 8 are inferior. This is related to the excessively high hot pressing pressure during the preparation of Comparative Example 8. Specifically, excessive hot pressing pressure can lead to greater internal stress in the board, making it more likely to crack from the core layer during cooling and demolding. Excessive hot pressing pressure can also destroy the natural structure of the wood fibers in the oyster mushroom sticks, especially the integrity of the long fibers, resulting in a decrease in the mechanical properties of the board.

[0159] The infrared spectrum of the plate in Comparative Example 9 before and after hot pressing showed that the -1 The vibration mode of the epoxy group in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening crosslinking reaction after hot pressing. -1 The C=O vibration mode intensity shows a significant weakening trend, indicating that the ester content of Comparative Example 9 after hot pressing is very low. Therefore, compared with Examples 1-3, the mechanical and water-resistant properties of Comparative Example 9 are inferior, which is related to the excessively low hot pressing pressure during the preparation of Comparative Example 9. Specifically, the excessively low hot pressing pressure is detrimental to the self-bonding of the cellulose from the oyster mushroom sticks within the board, the esterification reaction between citric acid and the cellulose from the oyster mushroom sticks, and the esterification reaction between citric acid and the epoxidized soybean oil.

[0160] The infrared spectrum of the plate in Comparative Example 10 before and after hot pressing showed that the -1 The vibration mode of the epoxy group in the epoxidized soybean oil disappeared after hot pressing, indicating that the epoxy soybean oil and citric acid underwent a ring-opening crosslinking reaction after hot pressing. -1The C=O vibration mode intensity shows a significant weakening trend, indicating that the ester content of Comparative Example 10 after hot pressing is very low. Therefore, compared with Examples 1-3, the mechanical and water-resistant properties of Comparative Example 10 are inferior, which is related to the excessively short hot pressing time during the preparation of Comparative Example 10. Specifically, the excessively short hot pressing time is not conducive to the esterification reactions between citric acid and cellulose from the Pleurotus ostreatus mushrooms, and between citric acid and epoxidized soybean oil within the board.

[0161] 3. Under hot pressing conditions, temperature will affect the mechanical properties of the board. The mechanical properties of the board obtained in Example 1 were tested under different hot pressing temperature conditions. The results are as follows: Figure 14 shown.

[0162] Figure 14 The mechanical properties of the oyster mushroom board prepared under different hot pressing temperature conditions are shown. Figure 14 As shown in the figure, the mechanical properties of the board reached a maximum at 120℃, which is mainly due to the fact that 120℃ is the optimal temperature for the esterification reaction between citric acid and cellulose. As the temperature continues to rise, the mechanical properties of the board reach a maximum at 180-190℃, which is mainly due to the fact that 180-190℃ is the optimal temperature for the esterification reaction between citric acid and epoxidized soybean oil.

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

[0164] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A formaldehyde-free energy-saving and waterproof board based on oyster mushroom sticks, characterized in that: Including the following parts by mass of raw materials: 60-65 parts of oyster mushroom stick 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.

2. The formaldehyde-free energy-saving and waterproof sheet based on oyster mushroom sticks according to claim 1, characterized in that: The oyster mushroom stick powder is obtained by grinding and sieving oyster mushroom sticks; the particle size of the oyster mushroom stick powder is 20 to 100 meshes.

3. The formaldehyde-free energy-saving and waterproof sheet based on oyster mushroom sticks according to claim 1, characterized in that: The surfactant is Tween 20.

4. The formaldehyde-free energy-saving and waterproof sheet based on oyster mushroom sticks according to claim 1, characterized in that: The formaldehyde-free energy-saving and waterproof board based on oyster mushroom sticks has an internal bonding 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 2h water absorption thickness expansion rate of 3.80-6.60%, and a 24h water absorption thickness expansion rate of 19.83-33.44%.

5. The method for preparing the formaldehyde-free energy-saving and waterproof sheet based on oyster mushroom sticks according to any one of claims 1 to 4, characterized in that: The steps include: The oyster mushroom stick powder, epoxy soybean oil, citric acid, surfactant and water are mixed evenly according to the prescribed amount, and then hot-pressed and cooled to obtain the formaldehyde-free energy-saving and waterproof board.

6. The preparation method according to claim 5, characterized in that The hot pressing is performed at a temperature of 120-190° C., a pressure of 18-20 tons, and a time of 1 hour.

7. The preparation method according to claim 5, characterized in that The cooling method is air cooling; the cooling time is 1 hour.

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