A processing method for long-term protective round bamboo

Abstract

The application discloses a processing method for long-acting protection of round bamboo. The surface of the round bamboo is cleaned, and the joints are broken. The pretreated round bamboo is subjected to wet heat treatment for 1-6 hours under the environmental conditions of 70-95% humidity and 70-95 DEG C temperature. The round bamboo after the wet heat treatment is dried at 60-90 DEG C. The dried round bamboo is subjected to heat modification for 1-6 hours in the environment of 100-160 DEG C. The inner and outer surfaces of the round bamboo are coated with wood wax oil or vegetable oil, and the coating is dried until the surface is solidified into a film. The method is suitable for processing of fresh round bamboo, effectively improves the surface quality, size stability and mildew-proof effect of the round bamboo, and widens the application region of the round bamboo as an engineering material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomass material processing, and particularly relates to a long-acting protection processing method of round bamboo. BACKGROUND

[0002] Bamboo is an important engineering material with light weight, high strength, hardness, wear resistance, high rigidity and good toughness. Making full use of bamboo can alleviate the contradiction between supply and demand of wood in the country and effectively supplement wood resources. Bamboo has defects of easy deformation and mildew in the utilization process. In order to protect the long-term utilization and engineering popularization of bamboo, it is necessary to protect the bamboo.

[0003] Compared with bamboo board, round bamboo has high material utilization rate and simple processing technology, but the structural characteristics of the epidermal layer, intermediate layer and pith ring are obviously different, so that the round bamboo is more susceptible to environmental humidity than the board. In addition, the permeability and adhesion of the surface of the round bamboo are obviously lower than those of wood and bamboo board, so the protection of the round bamboo often uses vacuum pressure impregnation and step modification technology, and has certain requirements for equipment. Fresh round bamboo needs to be dried before utilization or modification, and unreasonable drying will also cause defects of the round bamboo. Therefore, researchers are committed to exploring a round bamboo protection method convenient for industrial production. SUMMARY

[0004] In view of the problems that the round bamboo is susceptible to environmental humidity in the prior art and has relatively high requirements for equipment in the processing process, the application provides a long-acting protection processing method of round bamboo. The method is suitable for processing of fresh round bamboo, effectively improves the surface quality, dimensional stability and mildew-proof effect of the round bamboo, and widens the application region of the round bamboo as an engineering material.

[0005] The application is implemented by the following technical scheme:

[0006] A long-acting protection processing method of round bamboo comprises the following steps:

[0007] (1) Pretreatment: cleaning the surface of the round bamboo and breaking the joints;

[0008] (2) Wet heat treatment: wet heat treating the pretreated round bamboo under the environmental conditions of 70-95% humidity and 70-95 ℃ temperature for 1-6 h;

[0009] (3) Drying: drying the wet heat treated round bamboo at a drying temperature of 60-90 ℃;

[0010] (4) Heat modification: heat modifying the dried round bamboo in an environment of 100-160 ℃ for 1-6 h;

[0011] (5) Surface finishing: Use wood wax oil or vegetable oil to finish the inner and outer surfaces of the round bamboo. The coating dries until the surface solidifies into a film.

[0012] Furthermore, the round bamboo material is one of moso bamboo, cycad bamboo, red bamboo, purple bamboo, Phyllostachys pubescens, laurel bamboo, square bamboo and bamboo.

[0013] Furthermore, the drying method described in step (3) is one of kiln drying, microwave drying, and natural drying, and the drying is performed to a moisture content of 10-15%.

[0014] Furthermore, the drying method in step (3) is a kiln drying method, and the drying temperature is 70-80°C.

[0015] Furthermore, in step (4), the thermal modification is carried out at 120-140°C for 3-6 h.

[0016] Furthermore, the vegetable oil in step (5) is one of tung oil, linseed oil, palm oil, soybean oil, rapeseed oil, and coconut oil.

[0017] Furthermore, the number of coating times in step (5) is 2-3 times.

[0018] In the present invention, the surface of the round bamboo is cleaned and the bamboo nodes are opened before protection, which can not only improve the visual effect of the round bamboo, but also increase the protection life of the round bamboo surface coating. Opening the bamboo nodes can prevent the round bamboo from cracking due to changes in air pressure during the drying process, and facilitate the coating of the inner surface of the round bamboo; wet heat pretreatment of fresh round bamboo can reduce the cracks and cracks that appear during the drying process of fresh round bamboo, and improve the drying quality and drying speed of the round bamboo. Moreover, during the wet heat pretreatment process, the wax in the round bamboo migrates outward to form a dense and smooth surface layer, solving the problem that the silicon layer on the surface of the round bamboo is easy to fall off and has poor adhesion; finally, the protection of the round bamboo is completed by a two-step method of thermal modification and surface coating. The function of the bamboo cells is improved by low-temperature thermal modification of the round bamboo, and then the surface of the round bamboo is coated with wood wax oil or natural plant oil to further improve the dimensional stability and mildew resistance of the round bamboo.

[0019] The beneficial effects achieved by the present invention are:

[0020] The round bamboo processing method of the present invention can be directly used to process fresh round bamboo while maintaining the cylindrical structure of the round bamboo, effectively improving the surface quality, dimensional stability and mildew resistance of the round bamboo, broadening the application area of ​​round bamboo as an engineering material, and enhancing the market competitiveness of round bamboo. The processing method is simple and easy to implement and promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a bar graph showing the mass loss of round bamboo samples obtained from Examples 1 and 2 and Comparative Examples 1-5 after exposure to Coriolus versicolor for 8 weeks;

[0022] Figure 2 The swelling rates of the round bamboo samples processed in Examples 1 and 2 and Comparative Examples 1-5 along the wall thickness direction are as follows: at 23°C and when the ambient humidity increases from 65% to 100%. DETAILED DESCRIPTION

[0023] The following examples are merely examples of embodiments of the present invention and do not constitute any limitation thereto. Those skilled in the art will appreciate that modifications without departing from the spirit and scope of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0024] Example 1

[0025] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0026] (2) Wet heat treatment: The pretreated round bamboo was subjected to wet heat treatment for 3 h at a humidity of 95% and a temperature of 95 °C.

[0027] (3) Drying: The round bamboo timber after wet heat treatment is dried in a drying kiln at a drying temperature of 75°C until the moisture content of the round bamboo timber is 12%;

[0028] (4) Thermal modification: The dried round bamboo was thermally modified at 140 °C for 3 h.

[0029] (5) Surface finishing: Use wood wax oil to coat the inner and outer surfaces of the round bamboo twice, and let the coating dry until the surface solidifies into a film.

[0030] Example 2

[0031] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0032] (2) Wet heat treatment: The pretreated round bamboo was subjected to wet heat treatment for 1 h at a humidity of 70% and a temperature of 95°C.

[0033] (3) Drying: The round bamboo timber after the wet heat treatment is dried in a drying kiln at a drying temperature of 90°C until the moisture content of the round bamboo timber is 12%;

[0034] (4) Thermal modification: The dried round bamboo was thermally modified at 120 °C for 1 h.

[0035] (5) Surface finishing: Use wood wax oil to coat the inner and outer surfaces of the round bamboo once, and let the coating dry until the surface solidifies into a film.

[0036] Comparative Example 1

[0037] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0038] (2) Wet heat treatment: The pretreated round bamboo was subjected to wet heat treatment for 3 h at a humidity of 95% and a temperature of 95 °C.

[0039] (3) Drying: The round bamboo wood after heat and humidity treatment is naturally dried until the moisture content of the round bamboo wood is 12%;

[0040] (4) Thermal modification: The dried round bamboo was thermally modified at 160 °C for 6 h.

[0041] Comparative Example 2

[0042] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0043] (2) Wet heat treatment: The pretreated round bamboo was subjected to wet heat treatment for 3 h at a humidity of 95% and a temperature of 95 °C.

[0044] (3) Drying: The round bamboo wood after heat and humidity treatment is naturally dried until the moisture content of the round bamboo wood is 12%;

[0045] (4) Surface finishing: Use wood wax oil to coat the inner and outer surfaces of the round bamboo twice, and let the coating dry until the surface solidifies into a film.

[0046] Comparative Example 3

[0047] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0048] (2) Drying: The pre-treated round bamboo is naturally dried until the moisture content of the round bamboo is 12%;

[0049] (3) Thermal modification: The dried round bamboo was thermally modified at 140 °C for 3 h.

[0050] (4) Surface finishing: Use tung oil to coat the inner and outer surfaces of the round bamboo twice, and let the coating dry until the surface solidifies into a film.

[0051] Comparative Example 4

[0052] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0053] (2) Wet heat treatment: The pretreated round bamboo was subjected to wet heat treatment for 3 h at a humidity of 95% and a temperature of 95 °C.

[0054] (3) Drying: The round bamboo wood after heat and humidity treatment is naturally dried until the moisture content of the round bamboo wood is 12%;

[0055] Comparative Example 5

[0056] (1) Pretreatment: First, clean the surface of the round bamboo (moso bamboo), and then open up the bamboo joints;

[0057] (2) Drying: The pre-treated round bamboo is naturally dried until the moisture content of the round bamboo is 12%.

[0058] Performance testing:

[0059] 1. Anti-corrosion performance testing

[0060] This test is based on the national standard GB / T13942.1-2009 Durability of Wood Part 1: Laboratory Test Method for Natural Corrosion Resistance. The mass loss results of the samples obtained by the processing methods of Examples 1 and 2 and Comparative Examples 1-5 after exposure to Coriolus versicolor for 8 weeks are as follows: Figure 1 As shown. Figure 1 It can be seen that under the synergistic effect of thermal modification and surface protective coating, the anti-corrosion performance of round bamboo is effectively improved.

[0061] 2. Testing of hygroscopic dimensional stability

[0062] This test uses samples that have reached equilibrium in an environment with a temperature of 23°C and a humidity of 65% to test their dimensional stability. The test measures the change in the radial wall thickness of the round bamboo when the humidity increases from 65% to 100%. The results of the radial swelling rates of the samples obtained using the processing methods of Examples 1 and 2 and Comparative Examples 1-5 are shown in the figure below. Figure 2 As shown in the results, wet heat treatment can effectively improve the hygroscopic dimensional stability of round bamboo, and the humidity parameters of wet heat treatment have a greater influence on improving the dimensional stability of round bamboo. At the same time, under the synergistic effect of thermal modification and surface protective coating, the hygroscopic dimensional stability of round bamboo is further effectively improved.

Claims

1. A method for processing long-term protective round bamboo, characterized in that: The following steps are involved: (1) Pretreatment: Clean the surface of round bamboo and open up the bamboo joints; (2) Wet heat treatment: wet heat treatment of pretreated round bamboo for 1-6 h at a humidity of 70-95% and a temperature of 70-95 °C. (3) Drying: Dry the round bamboo after heat treatment at a temperature of 60-90°C until the moisture content reaches 10-15%; (4) Thermal modification: The dried round bamboo is thermally modified in an environment of 120-140°C for 3-6 hours; (5) Surface finishing: Use wood wax oil or vegetable oil to finish the inner and outer surfaces of the round bamboo. The coating dries until the surface solidifies into a film.

2. The method for processing long-lasting protective round bamboo according to claim 1, characterized in that: The round bamboo material is one of moso bamboo, cycad bamboo, red bamboo, purple bamboo, Phyllostachys pubescens, laurel bamboo, square bamboo and bamboo.

3. The method for processing long-lasting protective round bamboo according to claim 1, characterized in that: The drying method in step (3) is a kiln drying method or a microwave drying method.

4. The method for processing long-lasting protective round bamboo according to claim 3, characterized in that: The drying method in step (3) is kiln drying, and the drying temperature is 70-80°C.

5. The method for processing long-lasting protective round bamboo according to claim 1, characterized in that: The vegetable oil in step (5) is one of tung oil, linseed oil, palm oil, soybean oil, rapeseed oil, and coconut oil.

6. The method for processing long-lasting protective round bamboo according to claim 1, characterized in that: The number of times of coating in step (5) is 2-3 times.

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