Bamboo modification method based on in-situ packaging

Abstract

The invention discloses a bamboo modification method based on in-situ packaging. The method comprises the following steps: adding bamboo wood and a modifier A into a first dipping tank, and respectively carrying out dipping treatment and air drying to remove a solvent on the surface of the bamboo wood so as to obtain primary modified bamboo wood; and then, the primary modified bamboo wood and a modifier B are added into a second dipping tank, and after dipping treatment and curing treatment are conducted, the final modified bamboo wood is obtained. According to the method, zinc ions in the modifier A and imidazole-2-formaldehyde in the modifier B form a metal organic framework compound in the bamboo wood through two-step impregnation, meanwhile, packaging of the mildew preventive is achieved, the problem that packaged particles are difficult to disperse and impregnate is solved technically, a stable modification system is innovatively formed in the bamboo wood, and the service life of the bamboo wood is prolonged. The stability and slow release performance of the natural mildew preventive are improved, the bamboo wood is endowed with long-acting mildew-proof performance, and the physical and mechanical properties of the bamboo wood are enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of bamboo material processing, and in particular relates to a bamboo material modification method based on in-situ packaging. Background Art

[0002] Bamboo has a fast growth rate, high yield, and high mechanical strength. It is widely used in interior decoration, furniture manufacturing, flooring, and building structures. However, it is prone to mildew, which seriously affects the processing and application performance of the product. Therefore, bamboo needs to be treated with mildew prevention.

[0003] At present, the main method for improving the mildew resistance of bamboo is to immerse it in mildew inhibitors. Traditional mildew inhibitors have relatively good mildew resistance effects, but they are highly toxic and often contain heavy metal ions, which are potentially harmful to the environment and human body. In recent years, natural antibacterial ingredients such as plant essential oils have been applied to bamboo mildew resistance, showing good effects, and are safe and environmentally friendly, showing good application prospects. For example, patent CN115741921A uses modified loofah seed oil to immerse bamboo to achieve long-term mildew resistance. However, natural antibacterial ingredients are highly volatile and easily oxidized, especially when the board is processed, they are easily affected by high temperature and high pressure, and are easy to lose the mildew resistance effect. Therefore, it is necessary to improve the stability of such mildew inhibitors. The method of effectively improving the stability of mildew inhibitors by encapsulating mildew inhibitors in polymers and porous particles, but the encapsulated particles have problems such as difficulty in penetration and uneven distribution during the bamboo impregnation treatment process. At the same time, mildew resistance treatment has no significant effect on the physical and mechanical properties of bamboo, and even has a negative effect. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the object of the present invention is to provide a bamboo material modification method based on in-situ packaging.

[0005] The present invention is achieved by providing a bamboo material modification method based on in-situ encapsulation, the method comprising the following steps:

[0006] (1) placing a bamboo sample in a first immersion tank, maintaining the pressure at a negative pressure of 0.06 to 0.095 MPa for 10 to 30 minutes, adding a modifier A, maintaining the pressure at 0.4 to 0.8 MPa for 60 to 240 minutes, then soaking the bamboo sample at normal pressure for 8 to 24 hours, taking out the bamboo sample and air-drying the sample; wherein the modifier A is a mixed solution A dissolved in a solvent, and the mixed solution A is composed of a natural mildew inhibitor and zinc nitrate;

[0007] (2) placing the air-dried bamboo material in step (1) in a second impregnation tank, maintaining the pressure at a negative pressure of 0.06 to 0.095 MPa for 10 to 30 minutes, adding a modifier B, maintaining the pressure at 0.4 to 0.8 MPa for 60 to 240 minutes, taking out the bamboo material and curing it at 70 to 120° C. for 4 to 12 hours to obtain a modified bamboo material; wherein the modifier B is a mixed solution B dissolved in a solvent, the mixed solution B is composed of imidazole-2-carboxaldehyde and a catalyst, and the catalyst is selected from one or more of pyridine, triethylamine, and trioctylamine.

[0008] Preferably, in step (1), in the mixed solution A, the molar ratio of the natural mildew inhibitor to zinc nitrate is 1 to 3:1.

[0009] Preferably, in step (1), the natural mildew inhibitor is selected from one or more of citral, cinnamaldehyde and thymol.

[0010] Preferably, in step (2), the preparation process of the modifier B is: dispersing imidazole-2-carboxaldehyde in a solvent, heating to 60-100° C., stirring until fully dissolved, cooling to room temperature, filtering out insoluble matter, adding a catalyst, stirring evenly, and obtaining the modifier B.

[0011] Preferably, in step (2), the mass concentration of the catalyst in the modifier B is 2% to 3%.

[0012] Preferably, in step (1) and step (2), the solvent is selected from one or more of methanol, ethanol and dimethylformamide.

[0013] The present invention overcomes the shortcomings of the prior art and provides a bamboo modification method based on in-situ encapsulation. The present invention adds bamboo and modifier A into a first impregnation tank, and obtains primary modified bamboo after undergoing an impregnation treatment and air drying to remove the solvent on the surface of the bamboo; then, the primary modified bamboo and modifier B are added into a second impregnation tank, and after undergoing an impregnation treatment and a curing treatment, the final modified bamboo is obtained. In the present invention, through two-step impregnation, the zinc ions in the modifier A and the imidazole-2-carboxaldehyde in the modifier B form a metal organic framework compound inside the bamboo, and the encapsulation of the mildew inhibitor is achieved at the same time, which avoids the problem of difficult dispersion and impregnation of the encapsulated particles in the process, and innovatively forms a stable modification system inside the bamboo, which not only improves the stability and sustained release performance of the natural mildew inhibitor, and gives the bamboo a long-lasting mildew-proof performance, but also enhances the physical and mechanical properties of the bamboo.

[0014] Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

[0015] (1) The present invention utilizes natural products such as citral, cinnamaldehyde, thymol, etc. as bamboo antifungal agents, which are non-toxic and environmentally friendly;

[0016] (2) The present invention uses metal organic framework compounds to encapsulate natural mildew inhibitors inside bamboo, thus overcoming the problems of natural mildew inhibitors being easy to volatilize and oxidize, and achieves long-term mildew prevention of bamboo through the slow release of natural mildew inhibitors;

[0017] (3) The metal organic framework compound used in the present invention is rich in aldehyde groups and can react chemically with hydroxyl groups, carboxyl groups, etc. of bamboo materials, thereby improving the dimensional stability and mechanical strength of bamboo materials;

[0018] (4) The processing technology of the present invention has low requirements on equipment and is easy to promote industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a test result diagram of the anti-mildew performance of the modified bamboo material 2, the modified bamboo material 4 and the comparative bamboo material 1, the comparative bamboo material 2 before aging in the effect embodiment of the present invention;

[0020] Figure 2 It is a graph showing the anti-mildew performance test results of the modified bamboo material 2, the modified bamboo material 4 and the comparative bamboo material 1 and the comparative bamboo material 2 after aging in the embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] In the embodiments of the present invention, unless otherwise specified, various raw materials and equipment used are commercially available products known in the art.

[0023] Example 1

[0024] (1) 8.8 mmol of thymol and 8.8 mmol of zinc nitrate were fully dissolved in 200 g of methanol and stirred until fully dissolved to obtain a modifier A;

[0025] The bamboo sample was placed in the first immersion tank, maintained at a negative pressure of 0.095 MPa for 20 minutes, and modifier A was added to completely immerse the bamboo, and maintained at a pressure of 0.4 MPa for 120 minutes, and then immersed at normal pressure for 12 hours. The bamboo was taken out and placed in a fume hood to air-dry at room temperature;

[0026] (2) In order to quickly dissolve imidazole-2-carboxaldehyde to form a uniform and transparent solution, 70 mmol of imidazole-2-carboxaldehyde was dispersed in 200 g of methanol, heated to 60° C., stirred until fully dissolved, cooled to room temperature, insoluble matter was filtered off, pyridine was added, and stirred uniformly to obtain a modifier B, wherein the mass concentration of pyridine in the modifier B was 2%;

[0027] The air-dried bamboo material in step (1) is placed in a second impregnation tank, maintained at a negative pressure of 0.095 MPa for 20 minutes, and a modifier B is added to completely immerse the bamboo material. The pressure is maintained at 0.4 MPa for 120 minutes, and the bamboo material is taken out and cured at 85° C. for 12 hours to obtain a modified bamboo material 1.

[0028] Example 2

[0029] This Example 2 is basically the same as Example 1, and a modified bamboo material 2 is finally obtained. The difference is that in step (1), 26.4 mmol of thymol and 8.8 mmol of zinc nitrate are fully dissolved in 200 g of methanol and stirred until fully dissolved to obtain a modifier A.

[0030] Example 3

[0031] (1) 26.4 mmol of thymol and 8.8 mmol of zinc nitrate were fully dissolved in 200 g of dimethylformamide and stirred until fully dissolved to obtain a modifier A;

[0032] The bamboo sample was placed in the first immersion tank, maintained at a negative pressure of 0.095 MPa for 20 minutes, and modifier A was added to completely immerse the bamboo, and maintained at a pressure of 0.4 MPa for 120 minutes, and then immersed at normal pressure for 12 hours. The bamboo was taken out and placed in a fume hood to air-dry at room temperature;

[0033] (2) quickly dissolving imidazole-2-carboxaldehyde to form a uniform and transparent solution, dispersing 70 mmol of imidazole-2-carboxaldehyde in 200 g of dimethylformamide, heating to 60° C., stirring until fully dissolved, cooling to room temperature, filtering out insoluble matter, adding trioctylamine, stirring evenly, and obtaining a modifier B, wherein the mass concentration of trioctylamine in the modifier B is 3%;

[0034] The air-dried bamboo material in step (1) was placed in a second impregnation tank and maintained at a negative pressure of 0.095 MPa for 20 min. Modifier B was added to completely immerse the bamboo material. The pressure was maintained at 0.4 MPa for 120 min. The bamboo material was taken out and cured at 120° C. for 12 h to obtain modified bamboo material 3.

[0035] Example 4

[0036] This embodiment 4 is basically the same as the embodiment 1, and finally obtains the modified bamboo material 4, the difference being that:

[0037] In step (1), 26.4 mmol of cinnamaldehyde and 8.8 mmol of zinc nitrate are fully dissolved in 200 g of methanol and stirred until fully dissolved to obtain a modifier A.

[0038] Example 5

[0039] (1) 17.6 mmol of citral and 8.8 mmol of zinc nitrate were fully dissolved in 200 g of dimethylformamide to obtain a modifier A;

[0040] The bamboo sample was placed in the first immersion tank, maintained at a negative pressure of 0.06 MPa for 10 min, and modifier A was added to completely immerse the bamboo, maintained at a pressure of 0.8 MPa for 240 min, and then immersed at normal pressure for 24 h. The bamboo was taken out and air-dried at room temperature;

[0041] (2) Disperse 70 mmol of imidazole-2-carboxaldehyde in 200 g of ethanol, heat to 100° C., stir until fully dissolved, cool to room temperature, filter out insoluble matter, add trioctylamine, stir evenly, and obtain modifier B, wherein the mass concentration of trioctylamine in modifier B is 3%;

[0042] The air-dried bamboo material in step (1) was placed in a second impregnation tank and maintained at a negative pressure of 0.06 MPa for 10 min. Modifier B was added to completely immerse the bamboo material. The pressure was maintained at 0.8 MPa for 240 min. The bamboo material was taken out and cured at 120° C. for 12 h to obtain modified bamboo material 5.

[0043] Example 6

[0044] (1) 26.4 mmol of thymol and 8.8 mmol of zinc nitrate were fully dissolved in 200 g of methanol to obtain a modifier A;

[0045] The bamboo sample was placed in the first immersion tank, maintained at a negative pressure of 0.075 MPa for 30 minutes, and modifier A was added to completely immerse the bamboo, and maintained at a pressure of 0.4 MPa for 60 minutes, and then immersed at normal pressure for 8 hours. The bamboo was taken out and air-dried at room temperature;

[0046] (2) Dispersing 70 mmol of imidazole-2-carboxaldehyde in 200 g of methanol, heating to 80° C., stirring until fully dissolved, cooling to room temperature, filtering out insoluble matter, adding triethylamine, stirring evenly, and obtaining a modifier B, wherein the mass concentration of triethylamine in the modifier B is 2.5%;

[0047] The air-dried bamboo material in step (1) is placed in a second impregnation tank and maintained at a negative pressure of 0.075 MPa for 30 min. Modifier B is added to completely immerse the bamboo material. The pressure is maintained at 0.6 MPa for 60 min. The bamboo material is taken out and cured at 70° C. for 4 h to obtain modified bamboo material 6.

[0048] Comparative Example 1

[0049] The untreated bamboo material was dried at 103°C until it was absolutely dry, thereby obtaining comparative bamboo material 1.

[0050] Comparative Example 2

[0051] Comparative Example 2 is substantially the same as Example 1, and comparative bamboo material 2 is obtained. The difference is that in step (1), 8.8 mmol zinc nitrate is fully dissolved in 200 g methanol and stirred until fully dissolved to obtain modifier A.

[0052] Comparative Example 3

[0053] (1) adding 26.4 mmol of thymol to 200 g of methanol and stirring evenly to obtain a thymol methanol solution;

[0054] (2) The bamboo sample was placed in an immersion tank and maintained at a negative pressure of 0.095 MPa for 20 min. The above-mentioned thymol methanol solution was added to completely immerse the bamboo. The solution was maintained at 0.4 MPa for 120 min, and then immersed at normal pressure for 12 h. Finally, the bamboo was taken out and dried at 103°C to constant weight to obtain comparative bamboo 3.

[0055] Effect Example

[0056] 1. According to the national standard GB / T 18261-2013 "Test method for the efficacy of mildew inhibitors on wood mildew and discoloration fungi", the bamboo samples obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to mildew resistance tests. At the same time, the bamboo samples obtained in Examples 1 to 4 and Comparative Examples 1 to 2 were subjected to artificial aging tests (one cycle process was condensation at 45°C for 24 hours, ultraviolet irradiation at 60°C for 3.5 hours, spraying for 0.5 hours, and 7 cycles), and then mildew resistance tests were performed. The results are as follows: Figure 1 , 2 And as shown in Table 1.

[0057] Table 1 Anti-mildew grade of bamboo samples before and after aging

[0058]

[0059] From Table 1, Figure 1 and Figure 2 It can be seen that the modified bamboo material prepared by the method of the present invention has significant mildew resistance, and no mildew growth occurs on the surface of the modified bamboo material with a high content of natural mildew inhibitor. After aging, the mildew resistance level of the modified bamboo material does not decrease substantially, showing good long-term mildew resistance.

[0060] 2. The physical and mechanical properties of the bamboo samples of Examples 1 to 3 and Comparative Examples 1 to 2 were tested according to the national standard GB / T 15780-1995 "Test methods for physical and mechanical properties of bamboo materials". The results are shown in Table 2.

[0061] Table 2 Test results of physical and mechanical properties of bamboo samples

[0062]

[0063] It can be seen from Table 2 that the dimensional stability, water resistance and mechanical strength of the modified bamboo material prepared by the method of the present invention are greatly improved.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bamboo material modification method based on in-situ encapsulation, characterized in that: The method comprises the following steps: (1) placing a bamboo sample in a first immersion tank, maintaining the pressure at a negative pressure of 0.06 to 0.095 MPa for 10 to 30 minutes, adding a modifier A, maintaining the pressure at 0.4 to 0.8 MPa for 60 to 240 minutes, then soaking the bamboo sample at normal pressure for 8 to 24 hours, taking out the bamboo sample and air-drying the sample; wherein the modifier A is a mixed solution A dissolved in a solvent, and the mixed solution A is composed of a natural mildew inhibitor and zinc nitrate; (2) placing the air-dried bamboo material in step (1) in a second impregnation tank, maintaining the pressure at a negative pressure of 0.06 to 0.095 MPa for 10 to 30 minutes, adding a modifier B, maintaining the pressure at 0.4 to 0.8 MPa for 60 to 240 minutes, taking out the bamboo material and curing it at 70 to 120° C. for 4 to 12 hours to obtain a modified bamboo material; wherein the modifier B is a mixed solution B dissolved in a solvent, the mixed solution B is composed of imidazole-2-carboxaldehyde and a catalyst, and the catalyst is selected from one or more of pyridine, triethylamine, and trioctylamine.

2. The method according to claim 1, characterized in that In step (1), in the mixed solution A, the molar ratio of the natural mildew inhibitor to zinc nitrate is 1 to 3:

1.

3. The method according to claim 1, characterized in that In step (1), the natural mildew inhibitor is selected from one or more of citral, cinnamaldehyde and thymol.

4. The method according to claim 1, characterized in that In step (2), the preparation process of the modifier B is as follows: dispersing imidazole-2-carboxaldehyde in a solvent, heating to 60-100° C., stirring until fully dissolved, cooling to room temperature, filtering out insoluble matter, adding a catalyst, stirring evenly, and obtaining the modifier B.

5. The method according to claim 4, characterized in that In step (2), the mass concentration of the catalyst in the modifier B is 2% to 3%.

6. The method according to claim 1, characterized in that In step (1) and step (2), the solvent is selected from one or more of methanol, ethanol, and dimethylformamide.

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