Glue-free gluing enhanced bamboo laminated wood material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of bamboo material modification, and particularly relates to a glue-free gluing enhanced bamboo laminated wood material, a preparation method and application. The preparation method comprises the following steps: S1, mixing choline chloride and oxalic acid dihydrate, heating and stirring until the solution is clear to obtain a solution A; adding enzymatic hydrolysis lignin into the solution A, and stirring until the enzymatic hydrolysis lignin is completely dissolved to obtain a solution B; s2, the bamboo blocks are put into a solution B to be heated and soaked; after dipping is finished, heating is stopped, then deionized water is added, and stirring is conducted; the treated bamboo blocks are taken out, washed with deionized water and dried, and modified bamboo wood is obtained; s3, a layer of deionized water is evenly sprayed to the surface of the modified bamboo wood, and every two of the modified bamboo wood are aligned and assembled in the mode that the bamboo green faces face the bamboo green faces; and the assembled bamboo blocks are put into a hot press to be subjected to hot pressing, and the glue-free gluing enhanced bamboo laminated wood material is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of bamboo material modification, and in particular relates to a non-glue-bonded reinforced bamboo composite material, a preparation method and an application thereof. Background Art

[0002] Bamboo resources are widely distributed, grow rapidly, have strong regeneration, and have excellent mechanical properties. They show great application potential in the field of structural engineering. In addition, bamboo has a significant carbon sequestration capacity. Bamboo products are used to replace traditional structural building materials, which are green, cost-effective, and sustainable. However, natural bamboo is thin and hollow, with a sharp edge and bamboo nodes, which makes it more difficult to process. In particular, the narrow width of the original bamboo limits the size and scale of bamboo products, further restricting its large-scale industrial application.

[0003] Adhesives make it possible to lengthen and width bamboo and to prepare them on a large scale. In the field of bonding bamboo structural materials (bamboo laminated materials, reconstructed bamboo, etc.), phenolic resin adhesives are widely used due to their high bonding strength and excellent water resistance. However, the raw materials of phenolic resins come from non-renewable petrochemical resources, and the production process is complicated and energy-intensive, which increases the risk of global warming. In addition, phenolic resin adhesives release free formaldehyde during use, which is extremely harmful to human health. Therefore, in order to make bamboo and other biomass materials an effective substitute for traditional structural materials, it is urgent to develop more environmentally friendly and efficient bonding strategies. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0006] S1. Mix choline chloride and oxalic acid dihydrate, heat and stir until the solution is clear, to obtain solution A; add enzymatic lignin to solution A and stir until it is completely dissolved, to obtain solution B;

[0007] S2, putting the bamboo block into solution B for heating and impregnation treatment; after the impregnation is completed, turn off the heating, add deionized water, and stir; take out the treated bamboo block, wash it with deionized water and dry it to obtain the modified bamboo material;

[0008] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the bamboo blocks in pairs with the green bamboo faces facing each other; put the assembled bamboo blocks into a hot press for hot pressing to obtain a glue-free reinforced bamboo composite material.

[0009] Furthermore, in step S1, when preparing solution A, the molar ratio of choline chloride to oxalic acid dihydrate is 1:1, the heating temperature is 80° C., and the stirring time is 20 min.

[0010] Furthermore, in step S1, when preparing solution B, the mass ratio of solution A to enzyme lignin is 100:(2-10), the dissolution temperature is 80° C., and the stirring time is 5-25 min.

[0011] Furthermore, in step S2, the immersion treatment temperature of the bamboo block is 110° C., and the immersion treatment time is 20 minutes.

[0012] Furthermore, in step S2, the volume ratio of deionized water and solution B is (8-12):1, and the magnetic stirring time is 2 hours.

[0013] Furthermore, in step S2, the bamboo block is washed with deionized water for 3 to 5 times, and dried in an oven at 60° C. to obtain modified bamboo material.

[0014] Furthermore, in step S3, during hot pressing, the hot pressing temperature is 160° C., the hot pressing pressure is 2 MPa, and the hot pressing time is 15 min.

[0015] A non-glue-bonded reinforced bamboo composite material is prepared by the above-mentioned method for preparing the non-glue-bonded reinforced bamboo composite material.

[0016] The above-mentioned non-glue-bonded reinforced bamboo composite material is used as a raw material in the fields of furniture manufacturing, interior decoration, vehicle interior decoration and packaging materials.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention utilizes the dissolution of lignin by a low eutectic solvent and the regeneration effect in an anti-solvent to achieve reconstruction of the micro-nano rough surface of bamboo loaded with regenerated lignin, thereby improving the interfacial bonding strength of bamboo laminated materials. Through innovative bamboo surface modification technology, non-aldehyde, high-efficiency, green and glue-free bonding of bamboo laminated materials is achieved, and the surface of bamboo is modified in a green, simple and efficient way to obtain high-strength and stable bamboo-based engineering materials.

[0019] 2. The low eutectic solvent used in the present invention has good recyclability, and lignin is a cheap and sustainable renewable material, which complies with the principles of environmental protection and sustainable development, can reduce dependence on non-renewable resources, and is expected to break through the dependence of traditional bamboo laminated materials on "aldehyde" resin bonding, so as to develop green and efficient bonding technology for bamboo laminated materials. The research provides theoretical guidance and technical support for promoting the high-value and efficient utilization of lignin and the development of green glue-free bonding technology for bamboo materials, which is of great significance for the green innovation and sustainable development of the bamboo laminated material industry.

[0020] 3. The bamboo integrated timber prepared by the present invention does not release formaldehyde, thus solving the problem of free formaldehyde release during the experimental application of the bamboo integrated timber.

[0021] 4. The bamboo composite material prepared by the present invention has high bonding strength. The dry shear strength of the material is about 4.0 MPa, and the wet shear strength is about 3.0 MPa. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the experimental methods used in the following examples are all conventional operating methods.

[0024] Unless otherwise specified, the materials and reagents used in the following examples can be purchased from the market.

[0025] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0026] S1, mixing choline chloride and oxalic acid dihydrate, heating and stirring until the solution is clear, to obtain solution A; adding enzymatic lignin to solution A and stirring until it is completely dissolved, to obtain solution B; in step S1, when preparing solution A, the molar ratio of choline chloride to oxalic acid dihydrate is 1:1, the heating temperature is 80°C, and the stirring time is 20min; in step S1, when preparing solution B, the mass ratio of solution A to enzymatic lignin is 100:(2-10), the dissolution temperature is 80°C, and the stirring time is 5-25min;

[0027] S2, putting the bamboo block into solution B for heating and immersion treatment; after the immersion is completed, turn off the heating, add deionized water, and stir; take out the treated bamboo block, wash it with deionized water and dry it to obtain the modified bamboo material; the immersion treatment temperature of the bamboo block in step S2 is 110°C, and the immersion treatment time is 20min; the volume ratio of deionized water and solution B in step S2 is (8-12):1, and the magnetic stirring time is 2h; in step S2, the bamboo block is washed with deionized water for 3 to 5 times, and placed in an oven at 60°C for drying to obtain the modified bamboo material.

[0028] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0029] Specific examples and comparative examples are given below.

[0030] Embodiment 1

[0031] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0032] S1. Mix 250 g of choline chloride and 250 g of oxalic acid dihydrate, heat to 80° C. and stir until the solution is clear, to obtain solution A; add 5 g of enzymatically hydrolyzed lignin to solution A and stir at 80° C. for 10 min until completely dissolved, to obtain solution B;

[0033] S2, putting the bamboo block into solution B and heating it to 110° C. and immersing it for 20 minutes; after the immersion, turning off the heating, adding deionized water, the amount of deionized water is 20 times that of solution A by volume, and stirring; taking out the treated bamboo block, washing it with deionized water and drying it to obtain the modified bamboo material;

[0034] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0035] The mechanical properties were tested; the mechanical properties of the obtained double-layer bamboo composite material are shown in Table 1.

[0036] Embodiment 2

[0037] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0038] S1. Mix 250 g of choline chloride and 250 g of oxalic acid dihydrate, heat to 80° C. and stir until the solution is clear, to obtain solution A; add 10 g of enzymatically hydrolyzed lignin to solution A and stir at 80° C. for 10 min until completely dissolved, to obtain solution B;

[0039] S2, putting the bamboo block into solution B and heating it to 110° C. and immersing it for 20 minutes; after the immersion, turning off the heating, adding deionized water, the amount of deionized water is 20 times that of solution A by volume, and stirring; taking out the treated bamboo block, washing it with deionized water and drying it to obtain the modified bamboo material;

[0040] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0041] The mechanical properties of the obtained double-layer bamboo composite material are shown in Table 1.

[0042] Embodiment 3

[0043] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0044] S1. Mix 250 g of choline chloride and 250 g of oxalic acid dihydrate, heat to 80° C. and stir until the solution is clear, to obtain solution A; add 15 g of enzymatic lignin to solution A and stir at 80° C. for 10 min until it is completely dissolved, to obtain solution B;

[0045] S2, putting the bamboo block into solution B and heating it to 110° C. and immersing it for 20 minutes; after the immersion, turning off the heating, adding deionized water, the amount of deionized water is 20 times that of solution A by volume, and stirring; taking out the treated bamboo block, washing it with deionized water and drying it to obtain the modified bamboo material;

[0046] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0047] The mechanical properties of the obtained double-layer bamboo composite material are shown in Table 1.

[0048] Embodiment 4

[0049] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0050] S1. Mix 250 g of choline chloride and 250 g of oxalic acid dihydrate, heat to 80° C. and stir until the solution is clear, to obtain solution A; add 20 g of enzymatic lignin to solution A and stir at 80° C. for 10 min until it is completely dissolved, to obtain solution B;

[0051] S2, putting the bamboo block into solution B and heating it to 110° C. and immersing it for 20 minutes; after the immersion, turning off the heating, adding deionized water, the amount of deionized water is 20 times that of solution A by volume, and stirring; taking out the treated bamboo block, washing it with deionized water and drying it to obtain the modified bamboo material;

[0052] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0053] The mechanical properties of the obtained double-layer bamboo composite material are shown in Table 1.

[0054] Embodiment 5

[0055] A method for preparing a non-glue-bonded reinforced bamboo laminated material, the method comprising the following steps:

[0056] S1. Mix 250 g of choline chloride and 250 g of oxalic acid dihydrate, heat to 80° C. and stir until the solution is clear, to obtain solution A; add 25 g of enzymatic lignin to solution A and stir at 80° C. for 10 min until it is completely dissolved, to obtain solution B;

[0057] S2, putting the bamboo block into solution B and heating it to 110° C. and immersing it for 20 minutes; after the immersion, turning off the heating, adding deionized water, the amount of deionized water is 20 times that of solution A by volume, and stirring; taking out the treated bamboo block, washing it with deionized water and drying it to obtain the modified bamboo material;

[0058] S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the green bamboo faces to assemble them in pairs; put the assembled bamboo blocks into a hot press to obtain glue-free reinforced bamboo composite material; during the hot pressing, the hot pressing temperature is 160°C, the hot pressing pressure is 2MPa, and the hot pressing time is 15min.

[0059] The mechanical properties of the obtained double-layer bamboo composite material are shown in Table 1.

[0060] Comparative Example 1

[0061] (1) directly placing the bamboo block into a low eutectic solvent that does not dissolve enzymatic lignin, and immersing it at a temperature of 110° C. for 10 min;

[0062] (2) The bamboo blocks in step (1) are washed with deionized water, dried, and then hot-pressed to prepare double-layer bamboo laminated materials, and their mechanical properties are tested.

[0063] The bonding strength of the obtained double-layer bamboo laminated wood is shown in Table 1.

[0064] Table 1: Sample test results

[0065] Example Thousand Strength (MPa) Wet strength (MPa) Embodiment 1 1.08 one Embodiment 2 2.39 2.05 Embodiment 3 2.74 2.32 Embodiment 4 3.1 2.59 Embodiment 5 4.02 3.08 Comparative Example 1 0.98 one

[0066] The size of the bamboo block is 100×25×6mm3. It is hot pressed at 160℃ and 2MPa for 15min. It is slotted after hot pressing according to GB / T17657-2013. The gluing area is 25×25mm 2 , and then stored at room temperature for 24 hours to eliminate internal stress.

[0067] Experiments have shown that the method of strengthening bamboo composite materials by glue-free bonding described in the present invention, that is, strengthening bamboo composite materials by enzymatic lignin, is a green, simple and efficient bamboo surface modification method, and can thereby obtain high-strength and stable bamboo-based engineering materials.

[0068] The present invention has been described in detail above with general description and specific embodiments, but it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of the spirit of the present invention all belong to the scope of protection claimed in the present invention. In particular, the method is suitable for strengthening materials of bamboo, wood, straw, bagasse, reed stalks and similar biomass resources, and the use of the method to strengthen bamboo, wood, straw, bagasse, reed stalks and similar biomass resources materials, etc., all need to be protected.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", 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 representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0070] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a non-glue reinforced bamboo laminated material, characterized in that: The preparation method comprises the following steps: S1. Mix choline chloride and oxalic acid dihydrate, heat and stir until the solution is clear, to obtain solution A; add enzymatic lignin to solution A and stir until it is completely dissolved, to obtain solution B; S2, putting the bamboo block into solution B for heating and impregnation treatment; after the impregnation is completed, turn off the heating, add deionized water, and stir; take out the treated bamboo block, wash it with deionized water and dry it to obtain the modified bamboo material; S3. Spray a layer of deionized water evenly on the surface of the modified bamboo material, and align the bamboo blocks in pairs with the green bamboo faces facing each other; put the assembled bamboo blocks into a hot press for hot pressing to obtain a glue-free reinforced bamboo composite material.

2. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S1, when preparing solution A, the molar ratio of choline chloride to oxalic acid dihydrate is 1:1, the heating temperature is 80° C., and the stirring time is 20 min.

3. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S1, when preparing solution B, the mass ratio of solution A to enzyme lignin is 100:(2-10), the dissolution temperature is 80° C., and the stirring time is 5-25 min.

4. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S2, the immersion treatment temperature of the bamboo block is 110° C., and the immersion treatment time is 20 minutes.

5. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S2, the volume ratio of deionized water and solution B is (8-12):1, and the magnetic stirring time is 2h.

6. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S2, the bamboo block is washed with deionized water for 3 to 5 times, and dried in an oven at 60° C. to obtain modified bamboo material.

7. The method for preparing a non-glue reinforced bamboo laminated material according to claim 1, characterized in that: In step S3, during hot pressing, the hot pressing temperature is 160° C., the hot pressing pressure is 2 MPa, and the hot pressing time is 15 min.

8. A non-glue-bonded reinforced bamboo composite material prepared by the method for preparing a non-glue-bonded reinforced bamboo composite material according to any one of claims 1 to 7.

9. The non-glue-bonded reinforced bamboo composite material as claimed in claim 8 is used as a raw material in the fields of furniture manufacturing, interior decoration, vehicle interior decoration and packaging materials.