Preparation method of glue-free corn straw board

Abstract

The invention relates to a preparation method of a glue-free corn straw board, which comprises the following steps: crushing and screening corn straws to obtain corn straw powder meeting a preset fiber length as a raw material for preparing the glue-free corn straw board, carrying out high-temperature and high-pressure treatment on the raw material under a preset condition, and demolding to complete the preparation of the glue-free corn straw board. The method provided by the invention adopts a pure physical preparation method, only needs to crush the corn straw, and utilizes temperature and pressure conditions to enhance hydrogen bond grid formation and internal bonding effect in corn straw cellulose, hemicellulose and lignin, is simple and strong in operability, does not need any chemical agent, and is suitable for industrial production. Formaldehyde and organic volatile matters cannot be released into air, environmental pollution and damage to human health cannot be caused, and large-scale production and application of the glue-free corn straw board are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass material processing and preparation, and particularly relates to a method for preparing a glue-free corn stalk board. Background Art

[0002] Corn straw is an important biomass resource. China's annual production is as high as 270 million tons, most of which are burned, causing serious environmental pollution and great waste of resources. Vigorously developing comprehensive utilization methods and technical methods for corn straw is a scientific and technological problem that needs to be solved urgently. At present, the comprehensive utilization of corn straw includes returning corn straw to the field, using corn straw as feed, and using corn straw as raw materials. The main components of corn straw are cellulose, hemicellulose and lignin. Under high temperature and high pressure, a hydrogen bond grid is formed between lignin and other fibers. Cellulose can effectively increase the strength of the hydrogen bond grid, and the thermosetting resin generated by the solidification of hemicellulose acts as an internal binder. Therefore, using corn straw as raw material to prepare artificial straw board is one of the best ways to utilize corn straw as raw material.

[0003] The invention patent with publication number CN111300565A introduces an anticorrosive corn straw reconstituted material and a manufacturing method thereof. The method removes the leaves from the corn straw and then performs an anticorrosive treatment, then adds a resorcinol-modified phenolic resin adhesive to mix the adhesive, and then performs hot pressing and side pressing to prepare the anticorrosive corn straw reconstituted material. Although the adhesive resorcinol-modified phenolic resin used in this method can increase the strength of the board, it will release formaldehyde and organic volatiles into the air, causing environmental pollution and damage to human health. The invention patent with publication number CN113084960A provides a method for preparing corn straw boards without using adhesives. The method uses straw softening enzymes to etch the surface of the corn straw segment, then immerses it in a nanocellulose solution, and then performs hot pressing preparation. Although the invention does not use adhesives in the preparation process, the process of enzyme etching and cellulose impregnation greatly increases the complexity of the preparation process, consumes a lot of time and economic costs, and restricts the large-scale production of corn straw boards. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide a method for preparing a glue-free corn stalk board.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a glue-free corn stalk board comprises the following steps:

[0007] S1. Crush corn stalks, and screen to obtain corn stalk powder with a preset fiber length as a raw material for preparing a glue-free corn stalk board;

[0008] S2. The raw materials are subjected to high temperature and high pressure treatment under preset conditions, and demolding is performed to complete the preparation of the glue-free corn stalk board.

[0009] Furthermore, in step S1, the preset fiber length is 1 to 5 mm.

[0010] Further, in step S2, the preset condition is:

[0011] Applying high temperature and high pressure to the raw materials, and performing heat preservation and pressure preservation treatment;

[0012] The applied pressure ranges from 10 to 90 MPa, the applied temperature ranges from 20 to 150° C., and the pressure and temperature holding time is at least 2 hours.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention provides a method for preparing a glue-free corn straw board. The method provided by the present invention adopts a purely physical preparation method. It only needs to crush the corn straw, and then use temperature and pressure conditions to enhance the hydrogen bond grid formation and internal bonding effect in the cellulose, hemicellulose and lignin in the corn straw to prepare a green and environmentally friendly corn straw board whose tensile strength and bending strength meet international standards. In addition, the method provided by the present invention is simple to process the corn straw, and only needs to be crushed and sieved, and there is no need to separate the skin and pulp of the corn straw. It has strong operability and saves a lot of time and economic costs. The corn straw board prepared by the method provided by the present invention is not doped with any adhesive or other organic substances, and does not require any chemical agents. It will not release formaldehyde and organic volatiles into the air, will not cause environmental pollution and damage to human health, and is conducive to the green large-scale production and application of glue-free corn straw boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of a method for preparing a glue-free corn straw board provided by an embodiment of the present invention;

[0016] Figure 2 (a) and (b) are respectively a cross-sectional view of the test device assembly and a top view of the mold according to an embodiment of the present invention.

[0017] Figure 3 (a) and (b) are schematic diagrams showing the relationship between the bending strength and tensile strength of the glue-free corn stalk board under different pressure and temperature conditions in Examples 1-16 of the present invention as a function of pressure and temperature. DETAILED DESCRIPTION

[0018] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] The method for preparing the glue-free corn straw board provided by the present invention improves the hydrogen bond grid formation and internal bonding effect in the cellulose, hemicellulose and lignin of the corn straw by accurately and effectively controlling the temperature, pressure and time conditions of heat preservation and pressure retention, so as to prepare the glue-free corn straw board.

[0020] Figure 1 The flowchart of the method for preparing the glue-free corn straw board provided by the embodiment of the present invention is shown. Figure 1 As shown, an embodiment of the present invention provides a method for preparing a glue-free corn straw board, comprising the following steps:

[0021] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a straw crusher for crushing for 10 minutes. In the embodiment of the present invention, the corn stalks before crushing are cut into 50 cm small segments for the convenience of crushing. The cut length and subsequent crushing time can be adjusted according to the crusher used in the actual application, and the embodiment of the present invention does not limit this. The method provided by the present invention does not separate the pulp from the corn stalks, which can not only simplify the processing time of preparing the raw materials of the glue-free corn stalk board, but also is simpler and more convenient in actual operation, and saves time and economic costs.

[0022] The corn stalks are crushed, and in the embodiment of the present invention, corn stalk powder that meets the preset fiber length of 2 to 3 mm is screened and obtained as the raw material for preparing the glue-free corn stalk board. The instrument scale used in the embodiment of the present invention selects a fiber length of 2 to 3 mm. In actual application, if a hydraulic press or other instruments are used, 1 to 5 mm corn stalk powder can be selected for processing and molding according to actual conditions. The embodiment of the present invention does not limit this. The crushed corn stalk powder used in the embodiment of the present invention is used as the raw material for the glue-free corn stalk board. Corn stalk powder with uniform fiber length can be used. There is no need to mix raw materials with different fiber lengths, no additional cooking treatment and grinding of raw materials are required, and no additional biomass fiber is required. Most importantly, no chemical reagents are used for treatment, the process is short, the equipment requirements are simple, and there is no risk of environmental pollution.

[0023] S2. Put the crushed corn stalk powder as raw material into a small tablet press. The preset conditions in the embodiment of the present invention are: the applied pressure is 10-90MPa, the applied temperature range is 20-150°C, the pressure holding time is 2h, and the demolding completes the preparation of the glue-free corn stalk board. In the prior art, the board is formed and pressed, and it is usually necessary to dope some fiber materials or perform corresponding chemical, cooking and other pretreatments on the raw materials to obtain corn stalk boards that meet international standards. In the embodiment of the present invention, by precisely controlling the applied pressure, temperature and the time of heat preservation and pressure holding, the hydrogen bond grid formation and internal bonding effect in the cellulose, hemicellulose and lignin of the corn stalk are enhanced, that is, without doping other substances and pre-treating the raw materials, the flexural strength and tensile strength of the corn stalk board that meet international standards can be prepared. The pressure holding time in the embodiment of the present invention is 2h, and the board prepared for a time longer than 2h has the same strength as the board of 2h.

[0024] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, the raw materials are directly placed into two customized molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0025] In practical applications, the instrument can also be used to prepare a whole piece of glue-free corn stalk board, and then cut the glue-free corn stalk board that needs to be tested for bending strength and tensile strength. The embodiment of the present invention is for the convenience of testing, and the embodiment of the present invention is not limited to this.

[0026] In the embodiment of the present invention, the bending strength and tensile strength of the prepared glue-free corn stalk board are tested according to JIS A 5905:2003.

[0027] The following multiple embodiments are provided for the preparation method of the non-glue corn straw board of the present invention. In the embodiments of the present invention, the instrument used is a 30-ton HY-30 tablet press, the mold is customized according to the bending strength and tensile strength test standard of "JIS A 5905:2003", and the raw material is heated by a heating jacket. Figure 2 (a) and (b) show the assembly cross-sectional view of the test device and the top view of the mold according to the embodiment of the present invention. Figure 2 (a) is a schematic diagram of the assembly cross section of the experimental device HY-30 tablet press, where Figure 2 (b) The schematic diagram above is a top view of the bending test specimen mold. Figure 2 (b) The schematic diagram below is a top view of the tensile test specimen mold. Figure 2 shown.

[0028] Embodiment 1:

[0029] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0030] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0031] S2. The crushed corn stalk powder is used as raw material, and is placed in two customized molds for testing bending strength and tensile strength, respectively, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 14.8MPa, the applied temperature is 20°C, the pressure and temperature holding time is 2h, and the preparation of the glue-free corn stalk board is completed by demolding.

[0032] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 3.21g and 6.09g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0033] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 0.2 MPa and 0.3 MPa, respectively.

[0034] Embodiment 2:

[0035] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0036] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0037] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 14.8 MPa, the applied temperature is 50°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0038] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 3.51g and 5.91g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0039] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 7.4 MPa and 3.4 MPa, respectively.

[0040] Embodiment 3:

[0041] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0042] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0043] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 14.8 MPa, the applied temperature is 100°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0044] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 3.21g and 5.67g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0045] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested according to JIS A 5905:2003. The bending strength and tensile strength were 11.3 MPa and 7.6 MPa, respectively.

[0046] Embodiment 4:

[0047] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0048] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0049] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 14.8 MPa, the applied temperature is 150°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0050] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 3.19g and 5.86g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0051] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 26.2 MPa and 16.0 MPa, respectively.

[0052] Embodiment 5:

[0053] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0054] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0055] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 37.0 MPa, the applied temperature is 20°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0056] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 3.54g and 6.02g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0057] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 0.8 MPa and 1.0 MPa, respectively.

[0058] Embodiment 6:

[0059] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0060] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0061] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating jacket. The preset conditions in the embodiment of the present invention are: the applied pressure is 37.0 MPa, the applied temperature is 50°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0062] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 3.10g and 5.67g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0063] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 6.8 MPa and 4.5 MPa, respectively.

[0064] Embodiment 7:

[0065] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0066] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0067] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 37.0 MPa, the applied temperature is 100°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0068] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 3.00g and 5.44g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0069] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 12.3 MPa and 7.3 MPa, respectively.

[0070] Embodiment 8:

[0071] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0072] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0073] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating jacket. The preset conditions in the embodiment of the present invention are: the applied pressure is 37.0 MPa, the applied temperature is 150°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0074] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.93g and 5.36g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0075] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength was 29.1 MPa and the tensile strength was 15.7 MPa.

[0076] Embodiment 9:

[0077] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0078] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0079] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating jacket. The preset conditions in the embodiment of the present invention are: the applied pressure is 59.1 MPa, the applied temperature is 20°C, the pressure and temperature holding time is 2h, and the demolding completes the preparation of the glue-free corn stalk board.

[0080] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 3.05g and 5.62g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0081] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 1.5 MPa and 1.5 MPa, respectively.

[0082] Embodiment 10:

[0083] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0084] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0085] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 59.1 MPa, the applied temperature is 50°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0086] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.90g and 4.85g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0087] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 6.9 MPa and 4.6 MPa, respectively.

[0088] Embodiment 11:

[0089] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0090] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0091] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 59.1 MPa, the applied temperature is 100°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0092] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 3.01g and 5.16g of raw materials are directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength, respectively, to obtain the prepared glue-free corn straw board.

[0093] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength was 12.0 MPa and the tensile strength was 8.4 MPa.

[0094] Embodiment 12:

[0095] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0096] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0097] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 59.1 MPa, the applied temperature is 150°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0098] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn stalk board in the embodiment of the present invention, 2.95g and 5.59g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn stalk board.

[0099] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 30.0 MPa and 17.4 MPa, respectively.

[0100] Embodiment 13:

[0101] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0102] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0103] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 88.7 MPa, the applied temperature is 20°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0104] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.88g and 5.89g of raw materials are directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength, respectively, to obtain the prepared glue-free corn straw board.

[0105] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested according to JIS A 5905:2003. The bending strength and tensile strength were 3.1 MPa and 2.3 MPa, respectively.

[0106] Embodiment 14:

[0107] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0108] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0109] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 88.7 MPa, the applied temperature is 50°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0110] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.86g and 4.80g of raw materials are directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength, respectively, to obtain the prepared glue-free corn straw board.

[0111] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 7.8 MPa and 6.6 MPa, respectively.

[0112] Embodiment 15:

[0113] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0114] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0115] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 88.7 MPa, the applied temperature is 100°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0116] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.70g and 4.59g of raw materials are respectively directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength to obtain the prepared glue-free corn straw board.

[0117] The bending strength and tensile strength of the prepared glue-free corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 10.3 MPa and 10.7 MPa, respectively.

[0118] Embodiment 16:

[0119] The embodiment of the present invention provides a method for preparing a glue-free corn stalk board, comprising the following steps:

[0120] S1. Cut corn stalks into 50 cm small segments without separating the skin and pulp, and put the whole into a stalk crusher for 10 minutes. In the embodiment of the present invention, corn stalk powder with a preset fiber length of 2 to 3 mm is selected and obtained as the raw material for preparing the glue-free corn stalk board.

[0121] S2. The crushed corn stalk powder is used as raw material, and is placed in a customized mold, and then placed in a 30-ton HY-30 tablet press for pressurization and heating by a heating sleeve. The preset conditions in the embodiment of the present invention are: the applied pressure is 88.7 MPa, the applied temperature is 150°C, the pressure and temperature holding time is 2 hours, and the demolding completes the preparation of the glue-free corn stalk board.

[0122] In order to facilitate the testing of the bending strength and tensile strength of the prepared glue-free corn straw board in the embodiment of the present invention, 2.76g and 5.28g of raw materials are directly placed into two molds that can meet the requirements of testing the bending strength and tensile strength, respectively, to obtain the prepared glue-free corn straw board.

[0123] The bending strength and tensile strength of the prepared non-glue corn stalk board were tested in accordance with JIS A 5905:2003. The bending strength and tensile strength were 21.4 MPa and 21.7 MPa, respectively.

[0124] The data in the embodiment of the present invention are shown in Table 1 below:

[0125] Table 1

[0126]

[0127] The method for preparing glue-free corn straw board provided in the embodiment of the present invention not only provides the method for preparing corn straw board in the above pressure and temperature ranges, but also provides the test results of board strength in different pressure and temperature ranges. Figure 3 (a) and (b) show schematic diagrams of the relationship between the bending strength and tensile strength of the glue-free corn straw board under different pressure and temperature conditions in Examples 1-16 of the present invention as a function of pressure and temperature. As shown in Figure 3, it can be seen that in the embodiments of the present invention, by effectively controlling the pressure, temperature, and time conditions for heat preservation and pressure holding, the hydrogen bond grid formation and internal bonding effect in the cellulose, hemicellulose, and lignin of the corn straw are enhanced, the strength of the prepared corn straw board is increased, and the entire preparation method is simple and easy to operate. In addition, the present invention adopts a purely physical preparation method, does not contain any chemical harmful substances, is not doped with any adhesives and other organic substances, is environmentally friendly, conforms to the concept of green environmental protection, and is convenient for large-scale production of glue-free corn straw boards.

[0128] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0129] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0130] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a glue-free corn straw board, characterized in that: The following steps are involved: S1. Crush corn stalks, and screen to obtain corn stalk powder with a preset fiber length as a raw material for preparing a glue-free corn stalk board; S2. The raw materials are subjected to high temperature and high pressure treatment under preset conditions, and demolding is performed to complete the preparation of the glue-free corn stalk board.

2. The method for preparing the glue-free corn straw board according to claim 1, characterized in that: In step S1, the preset fiber length is 1 to 5 mm.

3. The method for preparing the glue-free corn straw board according to claim 2, characterized in that: In step S2, the preset condition is: Applying high temperature and high pressure to the raw materials, and performing heat preservation and pressure preservation treatment; The applied pressure ranges from 10 to 90 MPa, the applied temperature ranges from 20 to 150° C., and the pressure and temperature holding time is at least 2 hours.

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