Processing method of glue-free flame-retardant bamboo board

Abstract

The present application relates to the technical field of plate processing, in particular to a processing method of glue-free flame-retardant bamboo plate. The method comprises the following steps: soaking bamboo fiber in a mixed solvent to obtain a soaking material, mixing and stirring the soaking material with magnesium-based montmorillonite to obtain a mixed slurry, mixing and stirring the mixed slurry with a copper chloride solution to obtain a cross-linked mixed slurry, allowing the cross-linked mixed slurry to stand, filtering out the solvent to obtain a cross-linked mixed slurry from which the solvent is filtered out, and performing heating and pressurizing treatment to obtain the glue-free flame-retardant bamboo plate. The glue-free flame-retardant bamboo plate prepared by the processing method has high strength and does not need to be externally added with a glue. The flame-retardant performance is excellent, and the plate reaches A1 non-combustibility specified in GB 8624-2012. The bending strength is 4.2-4.6 MPa.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plate processing, in particular to a processing method of glue-free and flame-retardant bamboo plate. BACKGROUND

[0002] In order to prepare large-size bamboo plate, it is often necessary to split the bamboo into long strips and hot-press them under the action of adhesive. With the continuous progress of technology, bamboo flattening technology is becoming mature, and glue-free processing of large-size structural bamboo has become possible. However, glue-free processing of small products with relatively complex and delicate structure still needs technical innovation.

[0003] In addition, as a biomass material, it is extremely flammable, and the flame-retardant performance of the corresponding bamboo product needs to be solved. CN102259362A discloses a flame-retardant bamboo plate and a preparation method thereof, and the flame-retardant function is realized by a flame-retardant treatment liquid. However, the composition of the treatment liquid is not disclosed. CN108145815A discloses a preparation method of a flame-retardant bamboo plate, which not only needs to add a flame retardant, but also needs to add a large amount of adhesive (20%). CN114012861A discloses a preparation method of a flame-retardant bamboo plate without a flame retardant. Although this technology does not need to use a flame retardant, it avoids pollution to the environment caused by the flame retardant, and the preparation process needs to apply glue twice, which is relatively complex. Therefore, in the process of processing new bamboo, it is still necessary to further explore the preparation of various structures of bamboo without glue and without adding a flame retardant. SUMMARY

[0004] In order to solve the above problems, the present application provides a processing method of glue-free and flame-retardant bamboo plate. The bamboo plate processed by the preparation method provided by the present application has good flame-retardant performance and mechanical properties, and does not need to add an external adhesive, thereby avoiding the introduction of unsafe factors such as formaldehyde caused by the addition of adhesive.

[0005] In order to achieve the above purpose, the present application provides the following technical scheme:

[0006] The present application provides a processing method of glue-free and flame-retardant bamboo plate, comprising the following steps:

[0007] 1) Soaking the bamboo fiber in a mixed solvent to obtain a soaking material;

[0008] The mass percentage content of the non-aqueous solvent in the mixed solvent is 15-25%;

[0009] The non-aqueous solvent includes choline chloride and a hydrogen bond ligand. The hydrogen bond ligand includes any one of urea, propylene carbonate and ethylene carbonate;

[0010] The molar ratio of choline chloride to hydrogen bond ligand is 1:2;

[0011] 2) mixing, stirring the soaking material obtained in step 1) with magnesium-based montmorillonite to obtain a mixed slurry;

[0012] 3) mixing, stirring the mixed slurry obtained in step 2) with a copper chloride solution to obtain a cross-linked mixed slurry;

[0013] 4) standing the cross-linked mixed slurry obtained in step 3), and filtering out the solvent to obtain a cross-linked mixed slurry with the solvent filtered out;

[0014] 5) subjecting the cross-linked mixed slurry with the solvent filtered out obtained in step 4) to a heating and pressurizing treatment to obtain a glue-free flame-retardant bamboo board;

[0015] The heating and pressurizing treatment has the following conditions: the pressure is 15-40 MPa, the temperature is 140-185℃, the temperature rising rate is not higher than 10℃ / min, and the holding time is 25-50 min.

[0016] Preferably, the soaking in step 1) has the following conditions: the temperature is 20-30℃, and the time is 0.5-2 h.

[0017] Preferably, the mass ratio of the magnesium-based montmorillonite to the bamboo fibers in step 2) is 0.5-1.2:1.

[0018] Preferably, the mass percentage of the mixed slurry in step 2) is 20-25%.

[0019] Preferably, the mass ratio of the total mass of the bamboo fibers and the montmorillonite to the mass of the copper chloride solution in step 3) is 100:0.5-5.0.

[0020] Preferably, the mass percentage of the copper chloride solution in step 3) is 0.5%.

[0021] Preferably, the stirring in step 3) has the following conditions: the rotating speed is 1800-2800 rpm, and the stirring is performed until uniform.

[0022] Preferably, the standing time in step 4) is more than 0.5 h.

[0023] The present application has the following advantages:

[0024] The glue-free flame-retardant bamboo board prepared by the processing method has high strength and does not need additional adhesive. The flame-retardant performance is excellent, and reaches the A1 non-flammable level specified in GB 8624-2012. The bending strength is 4.2-4.6 MPa. DETAILED DESCRIPTION

[0025] The present application provides a processing method of a glue-free flame-retardant bamboo board, which comprises the following steps:

[0026] 1) soaking the bamboo fiber in a mixed solvent to obtain a soaking product;

[0027] The mass percentage of the non-water solvent in the mixed solvent is 15-25%;

[0028] The non-water solvent comprises choline chloride and a hydrogen bond ligand; the hydrogen bond ligand comprises any one of urea, propylene carbonate and ethylene carbonate;

[0029] The molar ratio of the choline chloride to the hydrogen bond ligand is 1:2;

[0030] 2) mixing and stirring the soaking product obtained in step 1) with magnesium-based montmorillonite to obtain a mixed slurry;

[0031] 3) mixing and stirring the mixed slurry obtained in step 2) with a copper chloride solution to obtain a crosslinked mixed slurry;

[0032] 4) standing the crosslinked mixed slurry obtained in step 3), and filtering out the solvent to obtain a crosslinked mixed slurry with the solvent filtered out;

[0033] 5) performing heating and pressurizing treatment on the crosslinked mixed slurry with the solvent filtered out obtained in step 4) to obtain a glue-free flame-retardant bamboo board;

[0034] The conditions of the heating and pressurizing treatment comprise: the pressure is 15-40 MPa, the temperature is 140-185℃, the temperature rising rate is not higher than 10℃ / min, and the holding time is 25-50 min.

[0035] In the present application, the bamboo fiber is soaked in a mixed solvent to obtain a soaking product; the mass percentage of the non-water solvent in the mixed solvent is 15-25%; the non-water solvent comprises choline chloride and a hydrogen bond ligand; the hydrogen bond ligand comprises any one of urea, propylene carbonate and ethylene carbonate; and the molar ratio of the choline chloride to the hydrogen bond ligand is 1:2. In the present application, the choline chloride is a hydrogen bond acceptor. In the present application, the non-water solvent has the effect of improving the solubility of the bamboo fiber and significantly improving the swelling and dissolving capacity of the mixed solvent for the bamboo fiber.

[0036] The obtained soaking material is mixed with magnesium-based montmorillonite to obtain a mixed slurry. In the present application, the mass ratio of the magnesium-based montmorillonite to the bamboo fiber is preferably 0.5-1.2:1. In the present application, the mass percentage of the mixed slurry is preferably 20-25%. In the present application, the magnesium-based montmorillonite functions to form an intercalation structure with the bamboo fiber, and the magnesium ions in the montmorillonite can form ionic bonding with the bamboo fiber to form a three-dimensional spatial network structure, which facilitates the bonding force between the fibers, the intercalation structure limits the entry of oxygen and the diffusion of carbon oxides, and the material is endowed with flame retardant function, and the introduction of magnesium ions further improves the flame retardant function. In the present application, the stirring conditions are preferably as follows: the stirring speed is 1800-2800 rpm, and the stirring is continued until uniformity.

[0037] The obtained mixed slurry is mixed with a copper chloride solution and stirred to obtain a crosslinked mixed slurry. In the present application, the mass ratio of the total mass of the bamboo fiber and the montmorillonite to the mass of the copper chloride solution is preferably 100:0.5-5.0. In the present application, the mass percentage of the copper chloride solution is preferably 0.5%. In the present application, the stirring conditions are preferably as follows: the stirring speed is 1800-2800 rpm, and the stirring is continued until uniformity. In the present application, the copper chloride functions to connect different cellulose molecules or hemicellulose molecules to form a network polymer system.

[0038] The obtained crosslinked mixed slurry is allowed to stand, and the solvent is filtered out to obtain a crosslinked mixed slurry from which the solvent is filtered out. In the present application, the standing time is preferably more than 0.5 h.

[0039] The obtained crosslinked mixed slurry from which the solvent is filtered out is subjected to heating and pressurization treatment to obtain a glue-free flame-retardant bamboo board; the heating and pressurization treatment conditions include: the pressure is 15-40 MPa, the temperature is 140-185℃, the temperature rising rate is not higher than 10℃ / min, and the holding time is 25-50 min.

[0040] In order to further illustrate the present application, the present application will be described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0041] Example 1

[0042] A processing method of a glue-free flame-retardant bamboo board, comprising the following steps:

[0043] 1) Soak the bamboo fiber in a mixed aqueous solution of choline chloride and ethylene carbonate with a concentration of 15wt.% at room temperature for 1 h, the mass ratio of the bamboo fiber to the mixed aqueous solution is 15:100, and the molar ratio of choline chloride to ethylene carbonate is 1:2.

[0044] 2) Subsequently, magnesium-based montmorillonite was added at a mass ratio of 0.5:1 with respect to the bamboo fiber, and stirring was performed to obtain a mixed slurry with a concentration of 20 wt.%.

[0045] 3) Copper chloride solution was added in the above mixed slurry at 1 wt.% with respect to the total mass of bamboo fiber and magnesium-based montmorillonite, and the mass percentage of copper chloride was 0.5%. Stirring was continuously performed during the mixing process at a stirring rate of about 1800 rpm until uniformity was achieved.

[0046] 4) After the crosslinked mixed slurry obtained in step 3) was allowed to stand for 0.5 h, the excess solvent was filtered out.

[0047] 5) The crosslinked mixed slurry with the filtered-out solvent was poured into a mold cavity and heated and pressurized, the pressure was controlled at 20 MPa, the temperature was 160℃, the heating rate was not higher than 10℃ / min, and the holding time was 30 min.

[0048] Cooling and demolding or immediate demolding obtained the glue-free flame-retardant bamboo board.

[0049] According to GB / T 5464-2010, the board was non-combustible and could not burn, reaching the highest A1 level of GB 8624-2012 Building Materials and Products Combustion Performance Classification.

[0050] According to GB / T 33099-2016, the bending strength of the board was 4.2 MPa.

[0051] Example 2

[0052] A processing method of a glue-free flame-retardant bamboo board, the steps are as follows:

[0053] 1) Bamboo fiber was soaked in a mixed aqueous solution of choline chloride and urea with a concentration of 25 wt.% at room temperature for 2 h, the mass ratio of bamboo fiber to mixed aqueous solution was 15:100, and the molar ratio of choline chloride to urea was 1:2.

[0054] 2) Subsequently, magnesium-based montmorillonite was added at a mass ratio of 1:0.8 with respect to the bamboo fiber, and stirring was performed to obtain a uniform mixed slurry with a concentration of 25 wt.%.

[0055] 3) Copper chloride solution was added in the above mixed slurry at 1.5 wt.% with respect to the total mass of bamboo fiber and montmorillonite, and the mass percentage of copper chloride was 0.5%. Stirring was continuously performed during the mixing process at a stirring rate of about 2000 rpm until uniform crosslinked mixed slurry was obtained.

[0056] 4) After the fluid obtained in the above step was allowed to stand for 0.5 h, the excess solvent was filtered out.

[0057] 5) The crosslinked mixed slurry with filtered solvent is poured into the mold cavity and heated and pressurized, the pressure is controlled at 25 MPa, the temperature is 165℃, the heating rate is not higher than 10℃ / min, and the holding time is 30 min.

[0058] Cooling demolding or immediate demolding gives the glue-free flame-retardant bamboo board.

[0059] According to GB / T 5464-2010, the board is non-combustible and cannot burn, reaching the highest A1 level of GB 8624-2012 Building Materials and Products Combustion Performance Classification.

[0060] According to GB / T 33099-2016, the bending strength of the board is 4.6 MPa.

[0061] Although the above embodiment has made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiment without creativity, which belongs to the protection scope of the present application.

Claims

1. A processing method of a glue-free flame-retardant bamboo board, characterized in that, The method comprises the following steps: 1) soaking the bamboo fibers in a mixed solvent to obtain a soaking product; The mass percentage of the non-water solvent in the mixed solvent is 15-25%; The non-water solvent comprises choline chloride and a hydrogen bond ligand, and the hydrogen bond ligand comprises any one of urea, propylene carbonate and ethylene carbonate; The molar ratio of choline chloride to the hydrogen bond ligand is 1:2; 2) mixing and stirring the soaking product obtained in step 1) with magnesium-based montmorillonite to obtain a mixed slurry; 3) mixing and stirring the mixed slurry obtained in step 2) with a copper chloride solution to obtain a crosslinked mixed slurry; 4) allowing the crosslinked mixed slurry obtained in step 3) to stand, and filtering out the solvent to obtain a crosslinked mixed slurry from which the solvent is filtered out; 5) performing heating and pressurization treatment on the crosslinked mixed slurry from which the solvent is filtered out obtained in step 4) to obtain a glue-free flame-retardant bamboo board; The heating and pressurization treatment conditions comprise a pressure of 15-40 MPa, a temperature of 140-185℃, a temperature rising rate of not higher than 10℃ / min, and a holding time of 25-50 min.

2. The method of claim 1 wherein, The soaking conditions in step 1) comprise a temperature of 20-30℃ and a time of 0.5-2 h.

3. The method of claim 1 wherein, The mass ratio of magnesium-based montmorillonite to bamboo fibers in step 2) is 0.5-1.2:

1.

4. The method of claim 1 wherein, The mass percentage of the mixed slurry in step 2) is 20-25%.

5. The method of claim 1 wherein, The mass ratio of the total mass of bamboo fibers and montmorillonite to the mass of the copper chloride solution in step 3) is 100:0.5-5.

0.

6. The method of claim 1 wherein, The mass percentage of copper chloride in the copper chloride solution in step 3) is 0.5%.

7. The method of claim 1 wherein, The stirring conditions in step 3) comprise a rotating speed of 1800-2800 rpm and stirring until uniform.

8. The method of claim 1 wherein, The standing time in step 4) is more than 0.5 h.