Bamboo-wood deep dyeing method

Abstract

The bamboo wood deep dyeing method comprises the following steps: 1) bleaching treatment: processing raw bamboo into bamboo pieces, and bleaching after cooking with bleaching agent; 2) modification treatment: modifying the bamboo pieces with 0.4-1.0% alkali liquor, and using ultrasonic wave in the process, and the treatment temperature is 65-75 DEG C, and the treatment time is 20-40 min, and after the treatment, the bamboo pieces are frozen, and after the freezing treatment, the bamboo pieces are thawed for use; 3) dyeing treatment: immersing the bamboo pieces treated in step 2) into 1-4% sucrose aqueous solution, and keeping the temperature at 40-60 DEG C in the process, and keeping the pressure in the tank at 0.05-0.5 MPa, and the dyeing treatment time is 3-5 h; 4) drying treatment: taking out the bamboo pieces treated in step 3), washing the surface floating color, and then drying. The bamboo wood deep dyeing method can further improve the penetration, uniformity and fixation effect of dyeing, and has significant progress compared with the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bamboo and wood dyeing, in particular to a bamboo and wood deep dyeing method. BACKGROUND

[0002] Bamboo and wood dyeing can increase the color and decoration effect of bamboo and wood. In the prior art, common bamboo and wood dyeing methods include brushing dyeing, spraying dyeing, and soaking dyeing. In brushing dyeing, a brush or other tool is used to evenly apply dye to the surface of a bamboo and wood product, and the brushing can be repeated as needed until the desired color saturation is achieved. In spraying dyeing, a spray gun or sprayer is used to evenly spray dye onto the bamboo and wood product to achieve uniform dyeing. In soaking dyeing, the bamboo and wood product is soaked in dye, and the soaking time depends on the dye used and the desired color effect. Longer soaking times generally produce deeper colors. In order to further ensure the environmental protection and safety of the product, the prior art further uses natural pigments such as sucrose to dye bamboo and wood. Chinese Patent Publication No. CN 103203787 B discloses a bamboo and wood tableware dyeing method using sucrose as a dyeing agent. Sucrose is dissolved in water to form a 3-10% sucrose solution by mass, the bamboo tableware is immersed in the sucrose solution, the solution is fully absorbed, the water is drained, and the bamboo product is then placed in a drying oven at 130-190°C for drying, thereby achieving a caramel color. In order to further improve the color rate and stability of the caramel color, Chinese Patent Publication No. CN 105365015 B further discloses a bamboo and wood physical dyeing method. The process used in this method includes bamboo and wood sawing, cooking, bleaching, first drying, first pressing, twice drying, twice pressing, and final treatment. This method has certain improvements in the permeability and dyeability of bamboo and wood. However, these technologies still have problems such as incomplete dyeing, further improvement of permeability, and poor dyeing uniformity in practical application. Therefore, the present application aims to develop a bamboo and wood deep dyeing method to improve the above-mentioned problems. SUMMARY

[0003] The technical problem solved by the present application is to provide a bamboo and wood deep dyeing method to solve the problems of incomplete dyeing, further improvement of permeability, and poor dyeing uniformity in the existing bamboo and wood dyeing process.

[0004] The technical problem solved by the present application is achieved by the following technical solution:

[0005] A bamboo and wood deep dyeing method, comprising the following steps:

[0006] 1) Bleaching treatment: After removing the bamboo green and the inner waxy layer of the original bamboo, the bamboo is processed into bamboo pieces; the bamboo and wood is cooked, then bleached with a bleaching agent, and after bleaching, the bamboo and wood is taken out and drained of water;

[0007] 2) modification treatment: the bamboo slices treated in step 1) are subjected to modification treatment by using 0.4-1.0% alkali liquor, ultrasonic wave is used in the treatment process, the treatment temperature is 65-75 DEG C, the treatment time is 20-40 min, after the treatment, the bamboo slices are subjected to freezing treatment, and after the freezing treatment, the bamboo slices are thawed for standby;

[0008] 3) dyeing treatment: the bamboo slices treated in step 2) are immersed in 1-4% sucrose aqueous solution, the temperature is kept at 40-60 DEG C in the dyeing process, the pressure in the tank is kept at 0.05-0.5 MPa, and the dyeing treatment time is 3-5 h;

[0009] 4) drying treatment: the bamboo slices treated in step 3) are taken out, the surface floating color is cleaned, and then the bamboo slices are dried.

[0010] Further, in step 1), the cooking is carried out by slow cooking with small fire, and the time is 1-2 h.

[0011] Further, in step 1), the bleaching agent is 10-15% hydrogen peroxide solution, and the bleaching time is 0.5-1 h.

[0012] Further, in step 2), the power of the ultrasonic wave is 1000-1200 W.

[0013] Further, in step 2), the freezing treatment is carried out by freezing the bamboo slices at-20 to-40 DEG C for 20-40 h.

[0014] Further, in step 2), the thawing treatment is carried out at 10-30 DEG C.

[0015] Further, in step 3), the dyeing treatment is carried out by using the method of temperature rising and pressure increasing.

[0016] Further, in step 3), the dyeing treatment is carried out by using the method of temperature rising and pressure increasing.

[0017] Further, in step 3), the cleaned bamboo slices are dried at 100-130 DEG C until the moisture content is 8-10%.

[0018] Beneficial effects: the bamboo wood deep dyeing method has the advantages that the fluid fuel can better penetrate into the bamboo wood, the dyeing depth, uniformity and firmness of the bamboo wood are significantly improved, and the method has good practical popularization and application value. DETAILED DESCRIPTION

[0019] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.

[0020] The bamboo wood deep dyeing method comprises the following steps:

[0021] 1) Bleaching treatment: after removing the bamboo green and the waxy layer inside the original bamboo, the bamboo is processed into bamboo pieces; the existing mechanical method can be used to remove the bamboo green and the waxy layer inside the bamboo to prevent the wax from affecting the adhesion and penetration of the fuel; the bamboo wood is cooked, and the bamboo pieces are slowly cooked with small fire for 1-2 hours; during the cooking process, the oil and impurities on the surface of the bamboo pieces are decomposed, and the fibers inside the bamboo pieces become soft, further preparing for dyeing; the process of fire and time control is relatively important, otherwise the subsequent dyeing effect will be affected. After cooking, the bamboo pieces are bleached with a bleaching agent, and then taken out and drained; preferably, the bleaching agent is a hydrogen peroxide solution with a mass fraction of 10-15%, and the bleaching time is 0.5-1h; the bamboo pieces are bleached with moderate concentration of hydrogen peroxide to achieve sufficient bleaching, reduce the negative impact of the original attached miscellaneous color of the bamboo pieces on the subsequent dyeing, and minimize the corrosion of high-concentration hydrogen peroxide to the bamboo pieces, affecting the stability of the structure of the bamboo pieces.

[0022] 2) Modification treatment: the bamboo pieces treated in step 1) are modified with an alkali solution with a mass fraction of 0.4-1.0%, and ultrasonic waves are used for assistance during the treatment, the treatment temperature is 65-75℃, and the treatment time is 20-40min; after the treatment, the bamboo pieces are frozen and then thawed for use. Under the above conditions, good modification effect is achieved. It is speculated that, in this process, the combination of low-concentration alkali solution and ultrasonic wave assistance at a given temperature range changes the pore structure inside the bamboo wood, so that more pores are changed from closed to open, improving the phenomenon that traditional fluid dyes cannot flow in closed pores, significantly improving the permeability, effectively improving the flow and penetration of fluid dyes inside the bamboo pieces, and further improving the uniformity of dyeing through the freezing treatment, the ice crystals formed inside the bamboo pieces break the inner wall of the pores to form cracks or cracks, so that the fluid dyes between adjacent pores are exchanged and replaced, further improving the uniformity of dyeing. The entire modification process changes the structure inside the bamboo pieces, and the pore structure becomes more complex, which can effectively reduce the backflow of the dyeing liquid inside the bamboo pieces during the subsequent dyeing and heating processes, thereby further improving the fixation effect.

[0023] In this process, the power of the ultrasonic wave is preferably 1000-1200W. It is speculated that too strong ultrasonic wave output can damage the internal pores, which in turn affects the permeability and further affects the dyeing and fixation effect, while too small ultrasonic wave power cannot achieve the synergistic effect with the alkali solution.

[0024] In this process, the freezing treatment involves freezing the bamboo strips at -20 to -40°C for 20 to 40 hours, and the thawing treatment is carried out at 10 to 30°C. It is important to note that slow freezing is used, rather than rapid freezing. During slow freezing, ice crystals grow fully, which facilitates the formation of larger ice crystals. This, in turn, facilitates the formation of pores or cracks on the pit walls, further enabling the dye liquor to enter and flow through.

[0025] 3) Dyeing treatment: Immerse the bamboo strips treated in step 2) in a 1-4% sucrose aqueous solution. During the dyeing process, maintain the temperature at 40-60℃, the pressure inside the tank at 0.05-0.5MPa, and the dyeing time at 3-5 hours. Preferably, the dyeing treatment is carried out by heating and pressurizing, so that the external dye solution enters the interior of the bamboo strips at a certain rate and slowly penetrates along the pit channels. The gradual process is conducive to further improving the dyeing uniformity. More preferably, the dyeing treatment is carried out by step heating and pressurizing, which can ensure the best effect. The temperature and pressure before and after step heating and pressurizing must be kept within the above range.

[0026] 4) Drying treatment: Remove the bamboo strips treated in step 3), wash off any surface stains, and then dry them. A preferred method is to dry the washed bamboo strips at a constant temperature of 100–130°C until the moisture content is 8–10%.

[0027] The bamboo and wood materials treated by the technology of this invention have excellent dyeing uniformity, guaranteed dyeing depth, good color fixation effect, and are environmentally friendly and safe, making them better suited for applications in kitchenware, children's toys, and other fields.

[0028] The following examples illustrate this point.

[0029] Example 1

[0030] A method for deep staining bamboo and wood includes the following steps:

[0031] 1) Bleaching treatment: Remove the outer green layer and inner wax layer from the raw bamboo, process it into bamboo strips of about 8mm, and then steam the bamboo over low heat for 1.8 hours. After steaming, bleach with a 12% hydrogen peroxide solution for 0.8 hours.

[0032] 2) Modification treatment: The bamboo strips treated in step 1) are modified with a 0.6% sodium hydroxide solution. In actual operation, the sodium hydroxide solution needs to completely cover the bamboo strips. Ultrasonic assistance is used during the treatment process. The power of the ultrasonic wave is 1200W, the treatment temperature is 70℃, and the treatment time is 30min. After the treatment, the bamboo strips are frozen and then thawed for later use. The freezing treatment is carried out by freezing the bamboo strips at -35℃ for 28h, and the thawing treatment is carried out at 20℃.

[0033] 3) Dyeing treatment: Dissolve sucrose in water to prepare a sucrose aqueous solution. Immerse the bamboo strips treated in step 2) in the 3% sucrose aqueous solution and perform dyeing treatment using a stepped heating and pressurization method. During the dyeing process, maintain the initial temperature at 40℃ and the initial pressure at 0.05MPa for 2.0h; after heating and pressurizing, maintain the temperature at 45℃ and the pressure at 0.2MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 50℃ and the pressure at 0.3MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 55℃ and the pressure at 0.4MPa for 1.0h.

[0034] 4) Drying treatment: Take out the bamboo strips treated in step 4), wash off the surface dye, and dry the washed bamboo strips at a constant temperature of 110℃ until the moisture content is about 9%.

[0035] Example 2

[0036] A method for deep staining bamboo and wood includes the following steps:

[0037] 1) Bleaching treatment: Remove the outer green layer and inner wax layer from the raw bamboo, process it into bamboo strips of about 8mm, and then steam the bamboo over low heat for 1.8 hours. After steaming, bleach with a 12% hydrogen peroxide solution for 0.8 hours.

[0038] 2) Modification treatment: The bamboo strips treated in step 1) are modified with a 1.0% sodium hydroxide solution. In actual operation, the sodium hydroxide solution needs to completely cover the bamboo strips. Ultrasonic assistance is used during the treatment process. The power of the ultrasonic wave is 1000W, the treatment temperature is 75℃, and the treatment time is 25min. After the treatment, the bamboo strips are frozen and then thawed for later use. The freezing treatment is carried out by freezing the bamboo strips at -40℃ for 20h, and the thawing treatment is carried out at 20℃.

[0039] 3) Dyeing treatment: Dissolve sucrose in water to prepare a sucrose aqueous solution. Immerse the bamboo strips treated in step 2) in the 3% sucrose aqueous solution and perform dyeing treatment using a stepped heating and pressurization method. During the dyeing process, maintain the initial temperature at 45℃ and the initial pressure at 0.1MPa for 1.5h; after heating and pressurizing, maintain the temperature at 50℃ and the pressure at 0.2MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 55℃ and the pressure at 0.3MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 60℃ and the pressure at 0.45MPa for 1.0h.

[0040] 4) Drying treatment: Take out the bamboo strips treated in step 4), wash off the surface dye, and dry the washed bamboo strips at a constant temperature of 110℃ until the moisture content is about 9%.

[0041] Comparative Example 1

[0042] A method for deep staining bamboo and wood includes the following steps:

[0043] 1) Bleaching treatment: Remove the outer green layer and inner wax layer from the raw bamboo, process it into bamboo strips of about 8mm, and then steam the bamboo over low heat for 1.8 hours. After steaming, bleach with a 12% hydrogen peroxide solution for 0.8 hours.

[0044] 2) Dyeing treatment: Sucrose is dissolved in water to prepare a sucrose aqueous solution. The bamboo strips treated in step 1) are immersed in the 3% sucrose aqueous solution. Dyeing treatment is carried out by stepwise heating and pressurization. During the dyeing process, the initial temperature is maintained at 40℃ and the initial pressure is 0.05MPa for 2.0h. After heating and pressurization, the temperature is 45℃ and the pressure is 0.2MPa for 1.0h. After further heating and pressurization, the temperature is 50℃ and the pressure is 0.3MPa for 1.0h. After further heating and pressurization, the temperature is 55℃ and the pressure is 0.4MPa for 1.0h.

[0045] 3) Drying treatment: Take out the bamboo strips treated in step 2), wash off the surface dye, and dry the washed bamboo strips at a constant temperature of 110℃ until the moisture content is about 9%.

[0046] Comparative Example 2

[0047] A method for deep staining bamboo and wood includes the following steps:

[0048] 1) Bleaching treatment: Remove the outer green layer and inner wax layer from the raw bamboo, process it into bamboo strips of about 8mm, and then steam the bamboo over low heat for 1.8 hours. After steaming, bleach with a 12% hydrogen peroxide solution for 0.8 hours.

[0049] 2) Modification treatment: The bamboo strips treated in step 1) are modified with a 2.5% sodium hydroxide solution. In actual operation, the sodium hydroxide solution needs to completely cover the bamboo strips. Ultrasonic assistance is used during the treatment process. The power of the ultrasonic wave is 2000W, the treatment temperature is 70℃, and the treatment time is 10min. After the treatment, the bamboo strips are frozen and thawed. The freezing treatment is to quickly freeze the bamboo strips to -35℃ and store them for 28h. The thawing treatment is carried out at 20℃.

[0050] 3) Dyeing treatment: Dissolve sucrose in water to prepare a sucrose aqueous solution. Immerse the bamboo strips treated in step 2) in the 3% sucrose aqueous solution and perform dyeing treatment using a stepped heating and pressurization method. During the dyeing process, maintain the initial temperature at 40℃ and the initial pressure at 0.05MPa for 2.0h; after heating and pressurizing, maintain the temperature at 45℃ and the pressure at 0.2MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 50℃ and the pressure at 0.3MPa for 1.0h; after further heating and pressurizing, maintain the temperature at 55℃ and the pressure at 0.4MPa for 1.0h.

[0051] 4) Drying treatment: Take out the bamboo strips treated in step 4), wash off the surface dye, and dry the washed bamboo strips at a constant temperature of 110℃ until the moisture content is about 9%.

[0052] Comparative Example 3

[0053] A method for deep staining bamboo and wood includes the following steps:

[0054] 1) Bleaching treatment: Remove the outer green layer and inner wax layer from the raw bamboo, process it into bamboo strips of about 8mm, and then steam the bamboo over low heat for 1.8 hours. After steaming, bleach with a 12% hydrogen peroxide solution for 0.8 hours.

[0055] 2) Modification treatment: The bamboo strips treated in step 1) are modified with a sodium hydroxide solution with a mass fraction of 0.6%. In actual operation, the sodium hydroxide solution needs to cover the bamboo strips. The treatment temperature is 70℃ and the treatment time is 30min. After the treatment, the bamboo strips are frozen and then thawed for later use. The freezing treatment is carried out by freezing the bamboo strips at -35℃ for 28h and the thawing treatment is carried out at 20℃.

[0056] 3) Dyeing treatment: Dissolve sucrose in water to prepare a sucrose aqueous solution. Immerse the bamboo strips treated in step 2) into the 3% sucrose aqueous solution and perform dyeing treatment in a constant temperature and pressure manner. The dyeing temperature is 50℃, the dyeing pressure is 0.3MPa, and the dyeing time is 5.0h.

[0057] 4) Drying treatment: Take out the bamboo strips treated in step 4), wash off the surface dye, and dry the washed bamboo strips at a constant temperature of 110℃ until the moisture content is about 9%.

[0058] Comparative Example 4

[0059] The staining was performed using the technical solution described in publication number CN 105365015 B.

[0060] The uniformity of dyeing was observed in bamboo strips dyed in Examples 1-2 and Control Examples 1-4. The processed bamboo strips were horizontally cut into multiple thin strips approximately 1 mm thick, and the color difference (ΔE) and uniformity between the strips were observed. Furthermore, a color-fixing effect test was conducted on bamboo strips dyed in Examples 1-2 and Control Examples 1-4. Each bamboo strip was boiled in boiling water for 1 hour and then placed at room temperature for 60 days, during which the degree of fading was observed. The results are shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] The results showed that the thin bamboo strips obtained in Examples 1 and 2 exhibited a relatively bright caramel color with minimal color difference between the strips, indicating that the dye could penetrate well into the inner layer of the bamboo strips, and the dye was evenly distributed across different locations on the same thin bamboo strip. In contrast, in Comparative Example 1, the color of the thin bamboo strips showed a visible gradient distribution from the surface to the inner layer, and the dye distribution was uneven across different locations on the same bamboo strip, highlighting the importance of modifying the bamboo strips before dyeing. In Comparative Example 2, the color difference between the thin bamboo strips was significant, and there were instances of dye concentration or blank areas on different locations on the same thin bamboo strip, indicating that controlling the modification conditions was crucial. Improper control of these conditions resulted in extremely poor dyeing effects. It is speculated that improper treatment may have further clogged the internal pores of the bamboo strips, reducing permeability and preventing the dye from flowing within the bamboo strips. In Comparative Example 3, no ultrasonic-assisted treatment was performed, and dyeing was carried out using a constant temperature and pressure method during drying. The results showed that the dye could not penetrate well into the inner layer of the bamboo strips, the dyeing uniformity was poor in the middle and inner layers, and there was fading. The color-fixing effect was also poor. This indicates that in the technical solution of the present invention, ultrasonic-assisted treatment and dyeing using a temperature and pressure method are both key steps. In Comparative Example 4, dyeing was performed using a traditional method. The dye could not reach the inner layer, and fading was easy, resulting in poor color-fixing. This shows that compared with the prior art, the present invention has achieved good results in terms of penetration and color-fixing effect.

[0065] The foregoing has shown and described 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. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for deep staining bamboo and wood, characterized in that, Includes the following steps: 1) Bleaching treatment: After removing the green bamboo and the waxy layer inside the bamboo, the raw bamboo is processed into bamboo strips; the bamboo is steamed and then bleached with a bleaching agent. After bleaching, it is taken out and drained. 2) Modification treatment: The bamboo strips treated in step 1) are modified with an alkaline solution of 0.4-1.0% by mass. Ultrasonic assistance is used during the treatment process. The power of the ultrasonic waves is 1000-1200W, the treatment temperature is 65-75℃, and the treatment time is 20-40min. After the treatment, the bamboo strips are frozen at -20 to -40℃ for 20-40h. After the freezing treatment, the bamboo strips are thawed and ready for use. 3) Dyeing treatment: Immerse the bamboo strips treated in step 2) in a 1-4% sucrose aqueous solution. During the dyeing process, maintain the temperature at 40-60℃, the pressure inside the tank at 0.05-0.5MPa, and the dyeing time at 3-5h. 4) Drying treatment: Take out the bamboo strips that have been treated in step 3), wash off the surface dye, and then dry them.

2. The method for deep dyeing bamboo and wood according to claim 1, characterized in that, In step 1), the steaming or boiling process is carried out over low heat for 1 to 2 hours.

3. The method for deep dyeing bamboo and wood according to claim 1, characterized in that, In step 1), the bleaching agent is a hydrogen peroxide solution with a mass fraction of 10-15%, and the bleaching time is 0.5-1h.

4. The method for deep staining bamboo and wood according to claim 1, characterized in that, In step 2), the thawing process is carried out at 10~30℃.

5. The method for deep staining bamboo and wood according to claim 1, characterized in that, In step 3), the dyeing process is carried out by increasing temperature and pressure.

6. The method for deep staining bamboo and wood according to claim 5, characterized in that, In step 3), a step-by-step heating and pressurization method is used for dyeing.

7. The method for deep staining bamboo and wood according to claim 1, characterized in that, In step 3), the cleaned bamboo strips are dried at a constant temperature of 100~130℃ until the moisture content is 8~10%.

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