CN118617536A - Micro-carbonization treatment method of bamboo and its products and applications - Google Patents

Abstract

The present invention discloses a micro-carbonization treatment method for bamboo, and its products and applications, comprising: (1) pre-treating bamboo to reduce the moisture content of bamboo by 15% to 20%; (2) heating bamboo with saturated water vapor; (3) placing the bamboo after the heat treatment in a shaping device and performing heat shaping treatment with saturated water vapor; (4) continuing to place the bamboo after the heat shaping treatment in the shaping device and gradually cooling it to room temperature, so as to obtain micro-carbonized bamboo. Compared with the bamboo before the treatment, the carbonized bamboo obtained by the micro-carbonization treatment method of the present invention has an increased density and good dimensional stability, and its mechanical properties such as MOR and MOE are significantly improved, and can maintain a stable data, which is basically not reduced with the use time, and the strength and curvature are significantly increased, anti-corrosion and mildew, prevent insects, reduce cracking rate, good weather resistance, and significantly increase the service life, and it has better application value as a material for construction or furniture.

Description

Micro-carbonization treatment method of bamboo and its products and applications

Technical Field

The invention relates to a bamboo processing method, in particular to a bamboo micro-carbonization processing method and a product thereof, and belongs to the field of bamboo micro-carbonization processing.

Background Art

Bamboo has the advantages of fast growth, short cycle, high strength and good toughness, and has been widely used as a manufacturing material in construction and furniture. However, raw bamboo is prone to cracking when used, which causes water and insects to invade, resulting in insect infestation and decay, which seriously affects its service life and greatly limits its application value and scope as a structural material. Therefore, the use of raw bamboo as a material for construction and furniture urgently needs to solve technical problems such as its easy cracking, poor anti-corrosion and anti-insect properties, and poor dimensional stability.

Summary of the invention

The main purpose of the invention is to provide a micro-carbonization treatment method for bamboo and a micro-carbonized bamboo product obtained thereby.

The above object of the present invention is achieved through the following technical solutions:

A micro-carbonization treatment method for bamboo, comprising:

(1) pre-treating the bamboo to reduce the moisture content of the bamboo by 15% to 20%;

(2) using high-temperature saturated steam to heat the bamboo;

(3) placing the heat-treated bamboo material in a shaping device and using high-temperature saturated water vapor to heat and shape the bamboo material;

(4) The bamboo material after the heat setting treatment is continuously placed in the setting device and gradually cooled to room temperature, thereby obtaining slightly carbonized bamboo material.

The bamboo materials described in the present invention are mainly various bamboo materials that have not been processed after felling, such as various bamboo materials such as Phyllostachys nanmu, Phyllostachys edulis, Phyllostachys pubescens, and Phyllostachys chinensis. These bamboo materials can be used as building or furniture materials after being processed.

As a preferred specific embodiment of the present invention, in step (1), the moisture content of the bamboo is reduced by 15% to 20% by a pretreatment method of hot air treatment; further preferably, the hot air treatment is carried out by blowing hot air at 65-75°C for 10-60 minutes, and most preferably, the hot air treatment is carried out by blowing hot air at 70°C for 30 minutes.

As a preferred specific embodiment of the present invention, the temperature of the high-temperature saturated water vapor in step (2) is 135-145°C, most preferably 140°C; the heating treatment time is 1-3 hours, most preferably 2 hours.

The bamboo is heat treated with high-temperature saturated steam. During this process, chemically bound water begins to dissipate, and water-soluble extracts are deposited on the bamboo surface as the water moves. The color of the bamboo changes from light yellow to light brown. At the same time, the thin-walled cells shrink, the cell volume decreases, the cellulose crystallinity increases, the lignin cross-linking degree increases, the weight of the bamboo decreases by 1.0% to 1.2%, the density increases by 5% to 7%, and the modulus of rupture (MOR), modulus of elasticity (MOE) and dimensional stability all increase.

As a preferred specific embodiment of the present invention, any shaping device described in step (3) or step (4) can be suitable for the present invention as long as it can fix the bamboo material in a required shape (such as bending). For example, conventional shaping devices for bamboo materials such as bending machines can be suitable for the present invention.

As a preferred specific embodiment of the present invention, the temperature of the high-temperature saturated water vapor in step (3) is 135-145°C, most preferably 140°C; the time of the heating and shaping treatment is 1-3 hours, most preferably 2 hours.

In the shaping device, high-temperature saturated water vapor is used to heat and shape the wood. In this process, as the water evaporates to reach equilibrium with the saturated water vapor, the hemicellulose content decreases, the α-cellulose content increases, the color of the bamboo becomes slightly darker, the degree of cross-linking of lignin is higher, the weight of the bamboo decreases by 1.4% to 1.5%, the density increases by 9% to 10%, and the mechanical properties are significantly improved.

As a preferred specific embodiment of the present invention, the step (4) of gradually cooling to room temperature is performed at a cooling rate of 10°C/min to room temperature, and the obtained bamboo material is light brown, and the modulus of rupture (MOR) and modulus of elasticity (MOE) are respectively increased by 18% to 20% and 17% to 25% compared with before the micro-carbonization treatment.

The carbonized bamboo material obtained by the micro-carbonization treatment method of the present invention has an increased density compared to that before the treatment, and its mechanical properties such as MOR and MOE are significantly improved, and can maintain a stable data, and basically does not decrease with the use time (if it is round bamboo, the MOR and MOE are about 5-10% decay per year), and the strength and curvature are significantly increased, the dimensional stability is good, and it has excellent anti-corrosion, anti-mildew and anti-insect properties, reduces the cracking rate, has good weather resistance, and significantly increases the service life. It has better application value as a material for construction or furniture.

For example, the bamboo material prepared by the micro-carbonization treatment method of the present invention is made into a guardrail for poultry enclosure. After the guardrail is used for 12 months, the cracks, elasticity, mechanical strength, etc. of the guardrail are tested to verify that the performance of the guardrail has not significantly decreased. The bamboo material prepared by the micro-carbonization treatment method of the present invention can also be used as a building material, including materials for buildings such as venues, park pavilions, and bamboo arch bridges, and the service life can reach 50 years; in contrast, if the bamboo material is not treated with the micro-carbonization of the present invention, its service life as a building material outdoors is only 3-5 years.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are exemplary only and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

Example 1 Micro-carbonization of round bamboo

The round bamboo was collected from Taipinghu Town, Huangshan City, Anhui Province, with a moisture content of 50%.

(1) Hot air blowing pretreatment: roller feeding (powered roller conveyor, roller diameter Shanghai Xiayun Conveying Machinery Equipment Co., Ltd.) method: 100 kg of round bamboo with a length of 1.5m-4.0m is fed, and hot air at 70°C is blown on the bamboo from top to bottom for 30 minutes, so that the moisture content of the bamboo is reduced by 20% before entering the feeding area, which is convenient for subsequent heat treatment;

(2) Thermoforming treatment:

① Heat treatment of bamboo with saturated water vapor: The bamboo was heated with saturated water vapor at 140℃ for 2h. During this process, chemically bound water began to dissipate, and the water-soluble extracts were deposited on the bamboo surface with the movement of water. The color of the bamboo changed from light yellow to light brown. At the same time, the thin-walled cells shrank, the cell volume decreased, the cellulose crystallinity increased, the lignin cross-linking degree increased, the bamboo weight decreased, the density increased, the modulus of rupture (MOR), modulus of elasticity (MOE) and dimensional stability increased.

Table 1 Bamboo related indicators before and after heating with 140℃ saturated steam

② Place the heat-treated bamboo in a device for shaping round bamboo and use saturated water vapor to heat-shape the bamboo:

The heat-treated round bamboo is placed in a device that can shape the round bamboo (for example, keep the round bamboo in a curved shape) and continues to heat the bamboo with saturated steam at 140±5℃ for 2 hours to perform a shaping heat treatment on the bamboo. In this process, as the water evaporates to reach equilibrium with the saturated steam, the hemicellulose content decreases, the α-cellulose content increases, the color of the bamboo becomes slightly darker, the degree of cross-linking of lignin is higher, the weight of the bamboo further decreases, the density increases, and the mechanical properties further increase.

Table 2 The relevant indicators of the bamboo before and after the heat-treated bamboo is placed in the device for shaping the round bamboo and continues to be heated and shaped with 140±5℃ saturated steam.

③ Gradually cool the bamboo material that has been shaped in the round bamboo shaping device to room temperature to obtain slightly carbonized bamboo material:

The bamboo material was continued to be fixed in the device for shaping the round bamboo, and the temperature was dropped to room temperature at a rate of 10°C/min. At this time, the bamboo material obtained was light brown, and the modulus of rupture (MOR) and modulus of elasticity (MOE) were significantly improved compared with those before the micro-carbonization treatment.

Table 3 Cooling stage - Properties of slightly carbonized bamboo obtained after cooling

Example 2 Micro-carbonization of round bamboo

The round bamboo was collected from Taipinghu Town, Huangshan City, Anhui Province, with a moisture content of 40%.

(1) Hot air blowing pretreatment: roller feeding (powered roller conveyor, roller diameter Shanghai Xiayun Conveying Machinery Equipment Co., Ltd.) method: 100 kg of round bamboo with a length of 1.5m-4.0m is fed, and hot air at 75°C is blown from top to bottom for 25 minutes, so that the moisture content of the bamboo is reduced by 20% before entering the feeding area, which is convenient for subsequent heat treatment;

(2) Thermoforming treatment:

① Heat treatment of bamboo with saturated water vapor: The bamboo was heated with saturated water vapor at 135℃ for 2.5h. During this process, chemically bound water began to dissipate, and the water-soluble extracts were deposited on the bamboo surface with the movement of water. The color of the bamboo changed from light yellow to light brown. At the same time, the thin-walled cells shrank, the cell volume decreased, the cellulose crystallinity increased, the lignin cross-linking degree increased, the bamboo weight decreased, the density increased, the modulus of rupture (MOR), modulus of elasticity (MOE) and dimensional stability all increased.

Table 4 Bamboo related indicators before and after heating with 135℃ saturated steam

② Place the heat-treated bamboo in a device for shaping the round bamboo (for example, keeping the round bamboo in a curved shape) and use saturated water vapor to heat-shape the bamboo:

The heat-treated round bamboo was placed in a round bamboo shaping device and continued to be heated with 135°C saturated steam for 2.5 hours to perform shaping heat treatment on the bamboo. In this process, as the water evaporates to reach equilibrium with the saturated steam, the hemicellulose content decreases, the α-cellulose content increases, the color of the bamboo becomes slightly darker, the degree of cross-linking of lignin is higher, the weight of the bamboo decreases, the density increases, and the mechanical properties are significantly improved.

Table 5 The relevant indicators of bamboo before and after the heat-treated bamboo is placed in the shaping device and continues to be heated and shaped by 135℃ saturated steam

③ Gradually cool the bamboo material that has been shaped in the round bamboo shaping device to room temperature to obtain slightly carbonized bamboo material:

The bamboo material was continued to be fixed in a device capable of shaping the round bamboo, and the temperature was dropped to room temperature at a rate of 10°C/min. At this time, the bamboo material obtained was light brown, and the modulus of rupture (MOR) and modulus of elasticity (MOE) were significantly improved compared with those before the micro-carbonization treatment.

Table 6 Cooling stage - Properties of slightly carbonized bamboo obtained after cooling

Example 3 Micro-carbonization of round bamboo

The round bamboo was collected from Taipinghu Town, Huangshan City, Anhui Province, with a moisture content of 40%.

(1) Hot air blowing pretreatment: roller feeding (powered roller conveyor, roller diameter Shanghai Xiayun Conveying Machinery Equipment Co., Ltd.) method: 100 kg of round bamboo with a length of 1.5m-4.0m is fed, and hot air at 65°C is blown on the bamboo from top to bottom for 45 minutes, so that the moisture content of the bamboo is reduced by 15% before entering the feeding area, which is convenient for subsequent heat treatment;

(2) Thermoforming treatment:

① Heat treatment of bamboo with saturated steam: The bamboo was heated with saturated steam at 145℃ for 1.5h. During this process, chemically bound water began to dissipate, and the water-soluble extracts were deposited on the bamboo surface with the movement of water. The color of the bamboo changed from light yellow to light brown. At the same time, the thin-walled cells shrank, the cell volume decreased, the cellulose crystallinity increased, the lignin cross-linking degree increased, the bamboo weight decreased, the density increased, the modulus of rupture (MOR), modulus of elasticity (MOE) and dimensional stability all increased.

Table 7 Bamboo related indicators before and after heating with 145℃ saturated steam

② Place the heat-treated bamboo in a device that can shape the round bamboo (for example, keep the round bamboo in a curved shape) and use saturated water vapor to heat-shape the bamboo:

The heat-treated round bamboo was placed in a device capable of shaping the round bamboo and continued to be heated with 145°C saturated steam for 1.5 hours to perform shaping heat treatment on the bamboo. In this process, as the water evaporates to reach equilibrium with the saturated steam, the hemicellulose content decreases, the α-cellulose content increases, the color of the bamboo becomes slightly darker, the degree of cross-linking of lignin is higher, the weight of the bamboo decreases, the density increases, and the mechanical properties are significantly improved.

Table 8 The relevant indicators of bamboo materials before and after the heat-treated bamboo materials are placed in the shaping device and continue to be heated and shaped by 145℃ saturated steam

③ Gradually cool the bamboo material that has been shaped in the round bamboo shaping device to room temperature to obtain slightly carbonized bamboo material:

The bamboo material was continued to be fixed in a device capable of shaping the round bamboo, and the temperature was dropped to room temperature at a rate of 10°C/min. At this time, the bamboo material obtained was light brown, and the modulus of rupture (MOR) and modulus of elasticity (MOE) were significantly improved compared with those before the micro-carbonization treatment.

Table 9 Cooling stage - Properties of slightly carbonized bamboo obtained after cooling

Claims (10)

1. A method for micro-carbonization of bamboo, comprising: (1) pre-treating the bamboo to reduce the moisture content of the bamboo by 15% to 20%; (2) using high-temperature saturated steam to heat the bamboo; (3) placing the heat-treated bamboo material in a shaping device and using high-temperature saturated water vapor to heat and shape the bamboo material; (4) The bamboo material after the heat setting treatment is continuously placed in the setting device and gradually cooled to room temperature, thereby obtaining slightly carbonized bamboo material. 2. The micro-carbonization treatment method according to claim 1 is characterized in that the bamboo materials are mainly various bamboo materials that have not been processed after being cut down. 3. The micro-carbonization treatment method according to claim 1, characterized in that the moisture content of the bamboo material is reduced by 15% to 20% by a pretreatment method of hot air treatment in step (1). 4. The micro-carbonization treatment method according to claim 3 is characterized in that the hot air treatment is carried out by blowing hot air at 65-75°C for 10-60 minutes, preferably, the hot air treatment is carried out by blowing hot air at 70°C for 30 minutes. 5. The micro-carbonization treatment method according to claim 1 is characterized in that the temperature of the high-temperature saturated water vapor in step (2) is 135-145°C, preferably 140°C; and the heating treatment time is 1-3 hours, preferably 2 hours. 6. The micro-carbonization treatment method according to claim 1, characterized in that the shaping device described in step (3) or step (4) is a device that can fix the bamboo material in a required shape. 7. The micro-carbonization treatment method according to claim 1 is characterized in that the temperature of the high-temperature saturated water vapor in step (3) is 135-145°C, preferably 140°C; the time of the heating and shaping treatment is 1-3 hours, preferably 2 hours. 8. The micro-carbonization treatment method according to claim 1, characterized in that the step (4) of gradually cooling down to room temperature is performed at a cooling rate of 10°C/min. 9. A micro-carbonized bamboo product obtained by the micro-carbonization treatment method according to any one of claims 1 to 8. 10. Use of the micro-carbonized bamboo product according to claim 9 as a material for construction or furniture manufacturing.