Method for removing wax coat of bamboo wood
Through composite treatment methods such as freezing, temperature and humidity difference, heat, acid and ultrasound, the problem of difficulty in completely removing the bamboo wax layer in the prior art is solved, and the physical characteristics of bamboo and the effective removal of the wax layer are achieved.
Patent Information
- Application Number
- CN202411928546.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-03-18
AI Technical Summary
The existing methods of removing waxy layers in bamboo are difficult to completely remove waxy layers under the conditions of maintaining the physical characteristics of bamboo, or there are problems of reducing material yield and cost.
The waxy layer on bamboo is treated with a variety of composite treatment methods such as freezing treatment, temperature and humidity difference treatment, heat treatment, acid treatment and ultrasonic treatment. Specific steps include temperature and humidity difference treatment after freezing treatment, followed by heat treatment, acid treatment and sonication treatment, and finally drying treatment.
Through this method, the bamboo waxy layer can be removed basically without residue while maintaining the physical characteristics of the bamboo, which improves the glueing performance and the wetting performance of the bamboo.
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Abstract
Description
Technical Field
[0001] The invention relates to the field of bamboo material processing, and more particularly to a method for removing a wax layer of bamboo material. Background Art
[0002] Bamboo is a renewable material with excellent physical and processability, and is widely used in furniture and construction. However, the waxy layer on the surface of bamboo has an adverse effect on the gluing properties of bamboo and the wetting properties of coatings.
[0003] Existing methods for removing the wax layer from bamboo mainly include physical removal methods and chemical removal methods. The physical removal method refers to removing the wax layer by grinding, planing, etc. This method has the problems of reducing the yield of bamboo and high cost. The chemical removal method refers to removing the wax layer by heat treatment or chemical reagent treatment. This method has the problem of residual wax layer under the condition of maintaining the physical properties of bamboo.
[0004] Therefore, how to provide a method for effectively removing the wax layer of bamboo while maintaining the physical properties of bamboo has become a technical problem that urgently needs to be solved in this field. Summary of the invention
[0005] One object of the present invention is to provide a new technical solution for a method of effectively removing the wax layer of bamboo while maintaining the physical properties of the bamboo.
[0006] According to a first aspect of the present invention, a method for removing a wax layer of bamboo is provided.
[0007] The method for removing the wax layer of bamboo comprises the following steps:
[0008] Step (1): freezing the fresh bamboo and then subjecting it to temperature and humidity difference treatment;
[0009] Step (2): heat-treating the bamboo material, wherein the heat-treatment system is firstly keeping the temperature at 75-85°C for 2-2.5 hours, and then heating to 115-125°C for 1-1.5 hours;
[0010] Step (3): treating the heat-treated bamboo material with an acid in an acid solution;
[0011] Step (4): subjecting the acid-treated bamboo material to ultrasonic treatment, wherein the ultrasonic treatment frequency is 24-60 Hz and the time is 0.15-0.2 h;
[0012] Step (5): drying the bamboo material after ultrasonic treatment.
[0013] Optionally, the freezing treatment in step (1) is specifically as follows:
[0014] Freeze the fresh bamboo at -18--20℃ for 24-30h.
[0015] Optionally, the temperature and humidity difference processing in step (1) is specifically as follows:
[0016] The frozen bamboo is placed in an environment where the temperature is 35-45°C higher than the freezing temperature and the humidity is at least 10% lower for 0.5-1h.
[0017] Optionally, the heat treatment in step (2) is specifically as follows:
[0018] First keep it at 75-85℃ for 2-2.5h, then increase the temperature to 100-105℃ and keep it for 0.5-1h, then increase the temperature to 115-125℃ and keep it for 1-1.5h, and then cool it to room temperature at a rate of 2-3℃ / min.
[0019] Furthermore, the heat treatment in step (2) is specifically as follows:
[0020] The bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
[0021] Optionally, the acidic solution in step (3) is a citric acid solution with a mass fraction of 40%, and the bamboo is stirred and soaked for 8 hours during the acid treatment process.
[0022] Optionally, the temperature of the ultrasonic treatment in step (4) is 20-25°C.
[0023] Optionally, the drying process in step (5) is specifically as follows:
[0024] Dry under hot air at 120°C for 2h.
[0025] The invention processes the wax layer on the bamboo material by multiple composite treatment means such as heat treatment, acid treatment and ultrasonic treatment, and can remove the wax layer on the bamboo material substantially without residue while maintaining the physical properties of the bamboo material. DETAILED DESCRIPTION
[0026] Various exemplary embodiments of the present invention will now be described in detail. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
[0027] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
[0028] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.
[0029] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.
[0030] The method for removing the wax layer of bamboo provided by the present invention comprises the following steps:
[0031] Step (1): freeze the fresh bamboo and then perform temperature and humidity difference treatment.
[0032] Freezing treatment can destroy some of the cell wall structures of fresh bamboo, making it easier for wax to flow out of the cells. Temperature and humidity difference treatment uses the difference in temperature and humidity to make wax precipitate quickly.
[0033] The freezing treatment in step (1) can be specifically as follows:
[0034] Freeze the fresh bamboo at -18--20℃ for 24-30h.
[0035] The temperature and humidity difference processing in step (1) can be specifically performed as follows:
[0036] The frozen bamboo is placed in an environment where the temperature is 35-45°C higher than the freezing temperature and the humidity is at least 10% lower for 0.5-1h.
[0037] The temperature and humidity differences in the freezing treatment and the temperature-humidity difference treatment can cause the wax layer in the bamboo material to precipitate, which is beneficial for removing the wax layer in the subsequent steps.
[0038] Step (2): heat-treating the bamboo material, wherein the heat-treatment system is to first keep the temperature at 75-85°C for 2-2.5 hours, and then raise the temperature to 115-125°C for 1-1.5 hours. The heat treatment can be hot air treatment.
[0039] The multi-stage heating treatment method can fully precipitate the wax in the siliceous cell layer of the bamboo, which is conducive to more complete and effective removal of the wax layer in subsequent steps.
[0040] Furthermore, the heat treatment of bamboo can be specifically as follows:
[0041] First keep it at 75-85℃ for 2-2.5h, then increase the temperature to 100-105℃ and keep it for 0.5-1h, then increase the temperature to 115-125℃ and keep it for 1-1.5h, and then cool it to room temperature at a rate of 2-3℃ / min.
[0042] The three-stage heating treatment method is conducive to more complete and effective removal of the wax layer. The temperature control and cooling treatment method is conducive to reducing the damage to the physical properties of bamboo and maintaining the excellent physical properties (especially toughness) and processability of bamboo.
[0043] Furthermore, the heat treatment in step (2) is specifically as follows:
[0044] The bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
[0045] Step (3): treating the heat-treated bamboo material in an acid solution.
[0046] Acid treatment can effectively remove the wax layer precipitated on the surface of bamboo.
[0047] In order to avoid the adverse effects of acidic solutions on bamboo materials in the field of edible contact products, the acidic solution in step (3) can be a citric acid solution. In specific implementation, the mass fraction of the citric acid solution can be 40%, so as to effectively peel off the wax layer while maintaining the physical properties of the bamboo material.
[0048] In order to improve the adequacy of the acid treatment, the bamboo can be stirred and soaked for 8 hours during the acid treatment process. The appropriate soaking time is conducive to maintaining the physical properties of the bamboo.
[0049] Step (4): subjecting the acid-treated bamboo material to ultrasonic treatment, wherein the ultrasonic treatment frequency is 24-60 Hz and the time is 0.15-0.2 h.
[0050] Ultrasonic treatment is beneficial to completely remove the wax remaining or adsorbed on the surface of bamboo and the acidic solution on the surface of bamboo.
[0051] The temperature of the ultrasonic treatment in step (4) can be 20-25° C. to maintain the excellent physical properties (especially toughness) and processability of the bamboo material.
[0052] Step (5): drying the bamboo material after ultrasonic treatment.
[0053] The drying process in step (5) is specifically as follows:
[0054] Dry under hot air at 120°C for 2h.
[0055] The invention processes the wax layer on the bamboo material by multiple composite treatment means such as heat treatment, acid treatment and ultrasonic treatment, and can remove the wax layer on the bamboo material substantially without residue while maintaining the physical properties of the bamboo material.
[0056] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials and reagents used are all commercially available unless otherwise specified. The equipment used in the experiments are all well known to those skilled in the art unless otherwise specified.
[0057] Example 1
[0058] Freeze fresh bamboo in an environment of -18℃ and 40% humidity for 24h, then place it in an environment of 25℃ and 20% humidity for 0.5h;
[0059] Then, the bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
[0060] Then, the bamboo was completely immersed in a 40wt% citric acid solution for 8h, and then taken out and rinsed;
[0061] Then the bamboo was placed in an ultrasonic device (50 Hz) for 10 min at 20 °C;
[0062] Finally, it was dried with hot air at 120°C for 120 min.
[0063] Example 2
[0064] Freeze fresh bamboo in an environment of -20℃ and 50% humidity for 24h, then place it in an environment of 20℃ and 35% humidity for 0.5h;
[0065] Then, the bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
[0066] Then, the bamboo was completely immersed in a 40wt% citric acid solution for 8h, and then taken out and rinsed;
[0067] Then the bamboo was placed in an ultrasonic device (60 Hz) for 10 min at 20 °C;
[0068] Finally, it was dried with hot air at 120°C for 120 min.
[0069] Comparative Example 1
[0070] The fresh bamboo was kept at 120℃ for 1.5h and then dried with hot air at 120℃ for 120min.
[0071] Comparative Example 2
[0072] Freeze fresh bamboo in an environment of -18℃ and 40% humidity for 24h, then place it in an environment of 25℃ and 20% humidity for 0.5h;
[0073] Then the bamboo was kept at 120°C for 1.5h;
[0074] Then, the bamboo was completely immersed in a 40wt% citric acid solution for 8h, and then taken out and rinsed;
[0075] Then the bamboo was placed in an ultrasonic device (50 Hz) for 10 min at 20 °C;
[0076] Finally, it was dried with hot air at 120°C for 120 min.
[0077] Comparative Example 3
[0078] Freeze fresh bamboo in an environment of -18℃ and 40% humidity for 24h, then place it in an environment of 25℃ and 20% humidity for 0.5h;
[0079] Then, the bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
[0080] Then the bamboo was placed in an ultrasonic device (50 Hz) for 10 min at 20 °C;
[0081] Finally, it was dried with hot air at 120°C for 120 min.
[0082] The wax layer thickness and surface distribution area of the bamboo obtained in each embodiment and comparative example were tested to obtain the wax content of the bamboo. The results are shown in Table 1.
[0083] Table 1 Test results of bamboo wax content
[0084]
[0085] As can be seen from Table 1, the wax layer of the bamboo obtained by the combined treatment method of the present application is substantially free of residues, and the treatment effect is good.
[0086] The mechanical properties of the bamboo materials obtained in each embodiment and comparative example were tested, and the results are shown in Table 2.
[0087] Table 2 Test results of bamboo mechanical properties
[0088]
[0089] It can be seen from Table 2 that the mechanical properties of the bamboo material obtained by the combined treatment method of the present application have not been significantly deteriorated, and the physical properties of the bamboo material have been maintained.
[0090] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.
Claims
1. A method for removing a waxy layer of bamboo, characterized in that: The steps include: Step (1): freezing the fresh bamboo and then subjecting it to temperature and humidity difference treatment; Step (2): heat-treating the bamboo material, wherein the heat-treatment system is firstly keeping the temperature at 75-85°C for 2-2.5 hours, and then heating to 115-125°C for 1-1.5 hours; Step (3): treating the heat-treated bamboo material with an acid in an acid solution; Step (4): subjecting the acid-treated bamboo to ultrasonic treatment, wherein the ultrasonic treatment frequency is 24-60 Hz and the time is 0.15-0.2 h; Step (5): drying the bamboo material after ultrasonic treatment.
2. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The freezing treatment in step (1) is specifically as follows: Freeze the fresh bamboo at -18--20℃ for 24-30h.
3. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The temperature and humidity difference processing in step (1) is specifically as follows: The frozen bamboo is placed in an environment where the temperature is 35-45°C higher than the freezing temperature and the humidity is at least 10% lower for 0.5-1h.
4. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The heat treatment in step (2) is specifically as follows: First keep it at 75-85℃ for 2-2.5h, then increase the temperature to 100-105℃ and keep it for 0.5-1h, then increase the temperature to 115-125℃ and keep it for 1-1.5h, and then cool it to room temperature at a rate of 2-3℃ / min.
5. The method for removing the wax layer of bamboo according to claim 4, characterized in that: The heat treatment in step (2) is specifically as follows: The bamboo was kept at 80°C for 2 hours, then heated to 100°C for 0.5 hours, then heated to 120°C for 1.5 hours, and then cooled to room temperature at a rate of 2-3°C / min.
6. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The acidic solution in step (3) is a citric acid solution with a mass fraction of 40%, and the bamboo is stirred and soaked for 8 hours during the acid treatment process.
7. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The temperature of the ultrasonic treatment in step (4) is 20-25°C.
8. The method for removing the wax layer of bamboo according to claim 1, characterized in that: The drying process in step (5) is specifically as follows: Dry under hot air at 120°C for 2h.