Efficient mildew-proof wood and bamboo material and modification method thereof

Abstract

The invention belongs to the field of environment-friendly materials, and discloses an efficient mildew-proof wood and bamboo material and a modification method thereof. The method comprises the following steps: impregnating wood or bamboo wood with a modification liquid containing an unsaturated organic acid monomer, heating to sequentially initiate an in-situ polymerization reaction and an esterification reaction, and drying to obtain the mildew-proof wood or bamboo wood. The prepared modified wood or bamboo has efficient mildew-proof performance while keeping the color and luster of the wood or bamboo, does not release irritant gas and is high in safety. When the concentration of the modifier reaches 1 wt% or above, the complete mildew-proof effect can be achieved. The modifier required by the method is low in concentration, high in mildew-proof efficiency and mild in reaction condition, can solve the problem that the wood or bamboo mildew-proof modification cost is difficult to compete with the mildew-proof agent due to the fact that the concentration of the current wood or bamboo modifier is higher than the use concentration (3%-5%) of the commercial mildew-proof agent, and has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection materials, and particularly relates to a highly efficient mildew-proof wood and bamboo material and its modification method. Background Art

[0002] Bamboo has the advantages of fast growth, large yield, and easy processing, and has been widely used in the fields of construction, papermaking, textile, furniture, etc. in recent years. Rubber wood has a light color, beautiful texture, small dry shrinkage, and a density ranging from light to medium, with good mechanical processing and finishing properties. However, both bamboo and rubber wood contain a large amount of nutrients, providing the nutrients required for the growth and reproduction of molds, resulting in easy mildew during storage, transportation, and use. Mildew not only affects the use value and economic value of wood and bamboo materials and their products, but also causes harm to human health. Therefore, the development of highly efficient mildew-proof treatment technologies for wood and bamboo materials is of great significance for promoting the efficient processing and utilization process and industrial development of wood and bamboo materials.

[0003] Chinese Patent Application CN114670301A discloses a bamboo material with mildew-proof performance and its modification method, in which 6-15% acrylamide derivative monomer and a catalyst are uniformly mixed to prepare a modification solution, and the acrylamide derivative monomer enters the interior of the bamboo through vacuum pressure impregnation, and a bamboo material with good mildew-proof performance is obtained after in-situ polymerization.

[0004] Chinese Patent Application CN119347908A discloses an anti-leaching mildew-proof modification method for wood and bamboo materials. The modification method emulsifies glycidyl methacrylate with a polybasic acid, and then adds a polymerization initiator to obtain a modification solution for modifying bamboo to obtain an anti-leaching bamboo material. When the solute concentration of the modification reagent reaches 8 wt% or more, the bamboo material has good anti-leaching performance and good mildew-proof effect.

[0005] Chinese Patent Application CN112959448A discloses a green and environmentally friendly bamboo mildew-proof method. The bamboo is immersed in an acid solution to obtain a modified bamboo. The bamboo treated with a 10% citric acid solution shows the best mildew-proof effect, and the control efficacy against 4 test bacteria is 75%.

[0006] The above-mentioned mildew-proof modification technologies for wood and bamboo materials all have the problem that the concentration of the modifier is higher than the use concentration (3%-5%) of commercial mildew-proof agents, making it difficult for the mildew-proof modification cost of wood and bamboo materials to compete with mildew-proof agents. Summary of the Invention

[0007] The purpose of the present invention is to overcome at least one deficiency of the prior art and provide a highly efficient mildew-proof wood and bamboo material and its modification method.

[0008] The technical solution adopted by the present invention is as follows: In the first aspect of the present invention, provided is: An efficient method for anti - mildew modification of wood and bamboo, the modification method comprising the following steps: S1) Prepare an anti - mildew modification liquid, the anti - mildew modification liquid containing an unsaturated organic acid monomer and a polymerization initiator; S2) Immerse the wood or bamboo in the anti - mildew modification liquid to allow the anti - mildew modification liquid to penetrate the wood or bamboo; S3) Take out the wood or bamboo after immersion is completed, and heat to initiate in - situ polymerization of the monomer to form poly - organic acid; S4) After the polymerization reaction is complete, further raise the temperature to cause the poly - organic acid to react with the wood or bamboo to undergo an esterification reaction, obtaining anti - mildew modified wood or bamboo.

[0009] In some examples, the unsaturated organic acid monomer is selected from at least one of acrylic acid, crotonic acid, and methacrylic acid.

[0010] In some examples, the concentration of the unsaturated organic acid monomer is 1 - 5 wt%.

[0011] In some examples, the polymerization initiator is selected from at least one of ammonium persulfate, potassium persulfate, hydrogen peroxide, and azodiisobutyramidine hydrochloride.

[0012] In some examples, the dosage of the polymerization initiator is 0.5 - 5% of the mass of the unsaturated organic acid monomer.

[0013] In some examples, the wood or bamboo is heated to 50 - 90 °C to initiate in - situ polymerization of the monomer to form poly - organic acid.

[0014] In some examples, the reaction time for in - situ polymerization of the monomer to form poly - organic acid is 1 - 12 hours.

[0015] In some examples, the temperature is raised to 100 - 160 °C to cause the poly - organic acid to react with the wood or bamboo to undergo an esterification reaction.

[0016] In some examples, the time for the esterification reaction is 1 - 6 hours.

[0017] In some examples, the bamboo is selected from Phyllostachys heterocycla cv. pubescens, Dendrocalamus giganteus, Phyllostachys violascens, and Dendrocalamus latiflorus, and the wood is selected from Hevea brasiliensis.

[0018] In some examples, the impregnation method is selected from one or more combinations of atmospheric pressure impregnation, vacuum impregnation, and pressure impregnation.

[0019] The above - mentioned features can be arbitrarily combined without conflict.

[0020] In the second aspect of the present invention, provided is: An efficiently anti - mildew modified wood and bamboo prepared by the method according to the first aspect of the present invention.

[0021] The beneficial effects of the present invention are as follows:

[0022] In the modification method of some examples of the present invention, when the concentration of unsaturated organic acid reaches 1 wt% or more, the wood or bamboo can achieve complete mildew-proof effect. After the monomers in the present invention enter the cell cavities of wood or bamboo, free radical polymerization reaction of unsaturated organic acid is initiated under low-temperature environment to form polyorganic acid. After drying treatment, it is deposited on the surface of cell walls and starch granules. Further heat treatment can make the polyorganic acid undergo esterification grafting reaction with the surface of cell walls and starch granules, realizing in-situ encapsulation of non-structural carbohydrates, forming a stable physical coating-esterification grafting structure, and blocking the utilization of non-structural carbohydrates by molds. Therefore, the modification of wood or bamboo with 1 wt% low-concentration unsaturated organic acid can achieve high-efficiency mildew-proof performance.

[0023] In the modification method of some examples of the present invention, on the one hand, the small-molecule modifiers polymerize into macromolecular polyorganic acids during the mildew-proof modification process, and at the same time further react and crosslink with the components inside the cells. There will be no VOC release during subsequent use, and the original structure of wood or bamboo will not be damaged. The wood or bamboo treated by mildew-proof modification not only has high-efficiency mildew-proof performance, but also has stable mildew-proof performance. The color and texture of the wood or bamboo before and after treatment have no obvious change, no irritating gas is released, and the safety is high. At the same time, the mechanical properties of wood or bamboo can be slightly enhanced. Description of the Drawings

[0024] Figure 1 It shows the change of the infected area in the mildew-proof test of Example 8 and Examples 1 - 5.

[0025] Figure 2 It shows the comparison photos before and after the mildew-proof test of Example 8 and Examples 1 - 5.

[0026] Figure 3 It shows the comparison photos before and after the mildew-proof test of Example 8 and Example 6.

[0027] Figure 4 It shows the SEM photos of the micro-morphology of Example 8 (a) and Example 1 (b). Detailed Embodiments

[0028] An efficient method for mildew-proof modification of wood and bamboo, the modification method includes the following steps: S1) Prepare a mildew-proof modification solution, the mildew-proof modification solution contains unsaturated organic acid monomers and polymerization reaction initiators; S2) Immerse the wood or bamboo in the mildew-proof modification liquid to allow the mildew-proof modification liquid to penetrate the wood or bamboo; S3) Take out the impregnated wood or bamboo and heat it to initiate in-situ polymerization of monomers to form polyorganic acids; S4) After the polymerization reaction is complete, further increase the temperature to cause the polyorganic acid to react with the wood or bamboo by esterification to obtain mildew-proof modified wood or bamboo.

[0029] In some examples, the unsaturated organic acid monomers are selected from at least one of acrylic acid, crotonic acid, and methacrylic acid. These monomers are easy to initiate polymerization to form polyorganic acids. At the same time, these monomers have relatively high solubility in water, and water can be used as a solvent.

[0030] The concentration of the monomers can be adjusted accordingly according to the mildew-proof effect. Generally speaking, the higher the concentration of the monomers, the better the mildew-proof effect, but the corresponding cost is also higher. In some examples, the concentration of the unsaturated organic acid monomers is 1-5 wt%. This can achieve a stable and lasting mildew-proof effect while the cost is relatively controllable.

[0031] There are no special requirements for the initiator, as long as it can be well dispersed in the modification liquid and initiate the corresponding polymerization reaction. The initiator can be used alone or in combination, and it is preferably used alone. In some examples, the polymerization reaction initiator is selected from at least one of ammonium persulfate, potassium persulfate, hydrogen peroxide, and azodiisobutyramidine hydrochloride.

[0032] The amount of the initiator should be sufficient to initiate the polymerization reaction. In some examples, the amount of the polymerization reaction initiator is 0.5-5% of the mass of the unsaturated organic acid monomers. This amount can initiate the polymerization well and has a relatively good reaction rate.

[0033] The temperature for in-situ polymerization of monomers to form polyorganic acids can be adjusted accordingly according to the type of monomers, as long as it can fully initiate a polymerization reaction with an appropriate reaction rate. In some examples, the wood or bamboo is heated to 50-90 °C to initiate in-situ polymerization of monomers to form polyorganic acids.

[0034] The time for in-situ polymerization of monomers to form polyorganic acids can be adjusted accordingly by monitoring the progress of the reaction. In some examples, the reaction time for in-situ polymerization of monomers to form polyorganic acids is 1-12 hours. This can ensure that the polymerization reaction is sufficient.

[0035] The temperature of the esterification reaction can be adjusted accordingly according to the type of monomers. The temperature should be able to initiate the esterification reaction while avoiding carbonization of the raw materials. In some examples, the temperature is raised to 100-160 °C to cause the polyorganic acid to react with the wood or bamboo by esterification.

[0036] The time of the esterification reaction can be adjusted accordingly by monitoring the progress of the reaction. In some examples, the time of the esterification reaction is 1 to 6 hours.

[0037] There is no requirement for the impregnation method, as long as the modification liquid can fully penetrate the wood or bamboo. In some examples, the impregnation method is selected from one or more combinations of atmospheric pressure impregnation, vacuum impregnation, and pressure impregnation.

[0038] The above features can be arbitrarily combined without conflict.

[0039] The content of the present invention will be further described below in conjunction with specific examples, but it should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well-known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0040] In the following examples, unless otherwise specified, the percentage concentrations refer to mass percentage concentrations. Example 1

[0041] S1) At room temperature, 500 mL of acrylic acid solutions with concentrations of (1 wt% - 5 wt%) were respectively prepared. 5 g, 10 g, 15 g, 20 g, and 25 g of acrylic acid were respectively weighed and added to 495 mL, 490 mL, 485 mL, 480 mL, and 475 mL of deionized water, and stirred to obtain clear and transparent acrylic acid solutions with concentrations of 1 wt% - 5 wt%. S2) 0.05 g, 0.10 g, 0.15 g, 0.20 g, and 0.25 g of ammonium persulfate were respectively weighed and added to the prepared acrylic acid solutions with concentrations of 1 wt% - 5 wt%, stirred and dissolved until clear and transparent. The de-haired and de-yellowed bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) were immersed in the acrylic acid solutions, placed in a vacuum pressure impregnation tank, vacuum impregnated at -0.08 MPa for 1 h first, then pressure impregnated at 0.8 MPa for 3 h, and after pressure relief, atmospheric pressure impregnated for 24 h. S3) The impregnated modified bamboo specimens were fished out, sealed and wrapped, and placed in an electrothermal blast drying oven. Heat treated at 60 °C for 8 h first to cause in-situ polymerization of acrylic acid monomers inside the bamboo to obtain polyacrylic acid, and then heat treated at 130 °C for 4 h to cause the obtained polyacrylic acid to further undergo esterification crosslinking with the bamboo to prepare the mildew-proof bamboo.

[0042] Mildew resistance test: Referring to GB / T 18261—2000, place the PDA medium in the air to fully inoculate it with airborne bacteria. Place two sterilized glass rods with a diameter of 3 mm in the petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28°C and a relative humidity of 85% for 4 weeks. Observe the degree of mildew, and evaluate the mildew resistance of the bamboo slices according to the GB / T 18261—2000 standard.

[0043] For the acrylic acid modified specimens with a concentration of 1 wt% - 5 wt% obtained in Example 1, the damage values within 4 weeks were all 0, indicating that when the modifier concentration was 1 wt% - 5 wt%, the modified bamboo could achieve complete mildew resistance, indicating that it successfully encapsulated the nutrients in the bamboo cell cavities and successfully isolated the source of mildew nutrients, with excellent mildew resistance performance (the mildew resistance results are as Figure 1 、 Figure 2 shown). Example 2

[0044] S1) Prepare a 500 mL acrylic acid solution with a concentration of 0.5 wt% at room temperature. Weigh 2.5 g of acrylic acid and add it to 497.5 mL of deionized water, and stir to obtain a clear and transparent acrylic acid solution with a concentration of 0.5 wt%. S2) Weigh 0.025 g of ammonium persulfate and add it to the prepared acrylic acid solution with a concentration of 0.5 wt%. Stir until dissolved and clear. Immerse the bamboo blocks of de - greened and de - yellowed dragon bamboo (length × width × thickness: 50 mm × 20 mm × 5 mm) in the acrylic acid solution, put them into a vacuum pressure impregnation tank, first perform vacuum impregnation at - 0.08 MPa for 1 h, then perform pressure impregnation at 0.8 MPa for 3 h, and perform normal - pressure impregnation for 24 h after pressure relief. S3) Take out the impregnated modified bamboo specimens, seal and wrap them, and place them in an electro - thermal blast drying oven. First, perform heat treatment at 60°C for 8 h to cause in - situ polymerization of acrylic acid monomers inside the bamboo to obtain polyacrylic acid, and then perform heat treatment at 130°C for 4 h to further esterify and cross - link the obtained polyacrylic acid with the bamboo to prepare mildew - resistant bamboo.

[0045] Mildew resistance test: Referring to GB / T 18261—2000, place the PDA medium in the air to fully inoculate it with airborne bacteria. Place two sterilized glass rods with a diameter of 3 mm in the petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28°C and a relative humidity of 85% for 4 weeks. Observe the degree of mildew, and evaluate the mildew resistance of the bamboo slices according to the GB / T 18261—2000 standard.

[0046] For the acrylic acid modified sample with a concentration of 0.5 wt% obtained in Example 2, the damage value within 4 weeks was 4. This indicates that when the modifier concentration was 0.5 wt%, due to the too low modifier concentration, the non-structural carbohydrates in the modified bamboo were not completely encapsulated, allowing molds to utilize the nutrients and grow on the modified bamboo, resulting in poor mildew-proof performance. Example 3

[0047] S1) Prepare 500 mL of acrylic acid solution with a concentration of 1 wt% at room temperature. Weigh 5 g of acrylic acid and add it to 495 mL of deionized water, and stir to obtain a clear and transparent acrylic acid solution with a concentration of 1 wt%. S2) Weigh 0.05 g of ammonium persulfate and add it to the prepared acrylic acid solution with a concentration of 1 wt%. Stir until it dissolves and becomes clear and transparent. Immerse the de-yellowed and de-greened moso bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) in the acrylic acid solution, put them into a vacuum pressure impregnation tank, first carry out vacuum impregnation at -0.08 MPa for 1 h, then carry out pressure impregnation at 0.8 MPa for 3 h, and carry out atmospheric impregnation for 24 h after pressure relief. S3) Take out the impregnated modified bamboo specimens, seal and wrap them, and place them in an electrothermal blast drying oven. First, carry out heat treatment at 60 °C for 8 h to cause in-situ polymerization of acrylic acid monomers inside the bamboo to obtain polyacrylic acid, and then carry out heat treatment at 100 °C for 4 h to obtain mildew-proof bamboo.

[0048] Mildew-proof test: Refer to GB / T 18261—2000. Place the PDA medium in the air to fully inoculate it with air-borne bacteria. Place two sterilized glass rods with a diameter of 3 mm in the petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28 °C and a relative humidity of 85% for 4 weeks, observe the degree of mildew, and evaluate the mildew-proof degree of the bamboo slices according to the GB / T 18261—2000 standard.

[0049] For the acrylic acid modified sample with a concentration of 1 wt% obtained in Example 3, the damage value within 4 weeks was 3. This indicates that when the modifier concentration was 1 wt% without heat treatment, since polyacrylic acid was only physically deposited in the cell lumen and not grafted onto the bamboo, polyacrylic acid was unstable in the modified bamboo and could not completely encapsulate the non-structural carbohydrates, allowing molds to utilize the nutrients, resulting in poor mildew-proof performance. Example 4

[0050] S1) Prepare 500 mL of acrylic acid solution with a concentration of 1 wt% at room temperature. Weigh 5 g of acrylic acid and add it to 495 mL of deionized water, and stir to obtain a clear and transparent acrylic acid solution with a concentration of 1 wt%. S2) Immerse the defrosted and de-yellowed moso bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) in the acrylic acid solution, put them into a vacuum pressure impregnation tank, first impregnate under -0.08 MPa vacuum for 1 h, then impregnate under 0.8 MPa pressure for 3 h, and impregnate at normal pressure for 24 h after depressurization; S3) Take out the impregnated modified bamboo specimens, seal and wrap them, and place them in an electrothermal blast drying oven. First, heat-treat at 60 °C for 8 h to cause in-situ polymerization of acrylic acid monomers inside the bamboo to obtain polyacrylic acid, and then heat-treat at 130 °C for 4 h to further esterify and crosslink the obtained polyacrylic acid with the bamboo to prepare mildew-proof bamboo.

[0051] Mildew-proof test: Refer to GB / T 18261—2000, place the PDA medium in the air to fully inoculate it with air-borne bacteria, place two sterilized glass rods with a diameter of 3 mm in a petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28 °C and a relative humidity of 85% for 4 weeks, observe the degree of mildew, and evaluate the mildew-proof degree of the bamboo slices according to the standard of GB / T 18261—2000.

[0052] The damage value of the 1 wt% concentration acrylic acid modified specimen obtained in Example 4 was 4 within 4 weeks, indicating that when the monomer concentration was 1 wt% and no initiator was added, the polymerization degree of acrylic acid monomers in the bamboo cell lumen was extremely low, and they existed in the form of monomers. During the heating process, acrylic acid monomer molecules underwent thermal motion and volatilized into the air, unable to encapsulate non-structural carbohydrates, enabling the nutrients in the modified bamboo to be utilized by molds, resulting in poor mildew-proof performance. Example 5

[0053] S1) Prepare a 500 mL solution of crotonic acid with a concentration of 1 wt% at room temperature. Weigh 5 g of crotonic acid and add it to 495 mL of deionized water, and stir to obtain a clear and transparent crotonic acid solution with a concentration of 1 wt%; Weigh 0.05 g of potassium persulfate and add it to the prepared 1 wt% concentration acrylic acid solution, stir and dissolve until clear and transparent. Immerse the defrosted and de-yellowed moso bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) in the crotonic acid solution, put them into a vacuum pressure impregnation tank, first impregnate under -0.08 MPa vacuum for 1 h, then impregnate under 0.8 MPa pressure for 3 h, and impregnate at normal pressure for 24 h after depressurization; S3) Take out the impregnated modified bamboo specimens, seal and wrap them, and place them in an electrothermal blast drying oven. First, heat-treat at 60 °C for 8 h to cause in-situ polymerization of crotonic acid monomers inside the bamboo to obtain polycrotonic acid, and then heat-treat at 130 °C for 4 h to further esterify and crosslink the obtained polycrotonic acid with the bamboo to prepare mildew-proof bamboo.

[0054] Mildew resistance test: Referring to GB / T 18261—2000, place the PDA medium in the air to fully inoculate with airborne bacteria. Place two sterilized glass rods with a diameter of 3 mm in a petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28 °C and a relative humidity of 85% for 4 weeks. Observe the degree of mildew, and evaluate the mildew resistance of the bamboo slices according to the standard of GB / T 18261—2000.

[0055] The damage value of the 1 wt% concentration of crotonic acid modified specimen obtained in Example 5 was 0 within 4 weeks, indicating that when the modifier concentration was 1 wt%, it could encapsulate non-structural carbohydrates, block the utilization of nutrients by mildew, and enable the modified bamboo to achieve complete mildew resistance with excellent mildew resistance performance. Example 6

[0056] S1) At room temperature, prepare 500 mL of methacrylic acid solutions with concentrations of (2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%) respectively. Weigh 10 g, 20 g, 30 g, 40 g, 50 g of methacrylic acid respectively, and add 490 mL, 480 mL, 470 mL, 460 mL, 450 mL of deionized water respectively. Stir to obtain clear and transparent methacrylic acid solutions with concentrations of 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt% respectively; S2) Weigh 0.1 g, 0.2 g, 0.3 g, 0.4 g, 0.5 g of ammonium persulfate respectively and add them to the prepared methacrylic acid solutions with concentrations of 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%. Stir until dissolved and clear. Immerse the de-haired and de-yellowed bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) in the methacrylic acid solution, put them into a vacuum pressure impregnation tank, first impregnate under a vacuum of -0.08 MPa for 1 h, then impregnate under a pressure of 0.8 MPa for 3 h, and impregnate at normal pressure for 24 h after pressure relief; S3) Take out the impregnated modified bamboo specimens, seal and wrap them, and place them in an electrothermal blast drying oven. First, perform heat treatment at 60 °C for 8 h to cause in-situ polymerization of methacrylic acid monomers inside the bamboo to obtain polymethacrylic acid, and then perform heat treatment at 130 °C for 4 h to further esterify and crosslink the obtained polymethacrylic acid with the bamboo to prepare mildew-resistant bamboo.

[0057] Mildew resistance test: Referring to GB / T 18261—2000, place the PDA medium in the air to fully inoculate it with airborne bacteria. Place two sterilized glass rods with a diameter of 3 mm in a petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28 °C and a relative humidity of 85% for 4 weeks. Observe the degree of mildew, and evaluate the mildew resistance of the bamboo slices according to the standard of GB / T 18261—2000.

[0058] The damage values of the 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% concentration methacrylic acid modified specimens obtained in Example 6 were all 0 within 4 weeks, indicating that using other unsaturated organic acid monomers as mildew-proof modifiers, the modified bamboo can achieve complete mildew prevention, indicating that it has successfully encapsulated the nutrients in the bamboo cell cavities and successfully isolated the source of mildew nutrients, and has excellent mildew resistance (the mildew prevention results are as Figure 3 shown). Example 7

[0059] S1) Prepare 500 mL of acrylic acid solutions with concentrations of (2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%) at room temperature respectively. Weigh 10 g, 20 g, 30 g, 40 g, and 50 g of acrylic acid respectively, and add 490 mL, 480 mL, 470 mL, 460 mL, and 450 mL of deionized water respectively, and stir to obtain clear and transparent acrylic acid solutions with concentrations of 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% respectively; S2) Weigh 0.1 g, 0.2 g, 0.3 g, 0.4 g, and 0.5 g of ammonium persulfate respectively and add them to the prepared acrylic acid solutions with concentrations of 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt%. Stir until dissolved and clear. Immerse the rubberwood blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) specimens in the acrylic acid solution, put them into a vacuum pressure impregnation tank, first impregnate under -0.08 MPa vacuum for 1 h, then impregnate under 0.8 MPa pressure for 3 h, and after depressurization, impregnate at normal pressure for 24 h; S3) Take out the impregnated rubberwood specimens, seal and wrap them, and place them in an electrothermal blast drying oven. First, heat-treat at 60 °C for 8 h to cause in-situ polymerization of acrylic acid monomers inside the bamboo to obtain polyacrylic acid, and then heat-treat at 130 °C for 4 h to further esterify and crosslink the obtained polyacrylic acid with the wood to prepare mildew-proof rubberwood.

[0060] Mildew resistance test: Referring to GB / T 18261—2000, place the PDA medium in the air to fully inoculate it with airborne miscellaneous bacteria. Place two sterilized glass rods with a diameter of 3 mm in the petri dish, and place two specimens horizontally on the glass rods. Immediately after inoculation, place the petri dish in an incubator at a temperature of 28 °C and a relative humidity of 85% for 4 weeks. Observe the degree of mildew, and evaluate the mildew resistance of the bamboo slices according to the standard of GB / T 18261—2000.

[0061] For the acrylic acid modified rubberwood specimens with concentrations of 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% obtained in Example 7, the damage values within 4 weeks are all 0, indicating that when the concentration of the modifier reaches 2 wt% or more, the modified rubberwood can achieve complete mildew resistance, indicating that it has successfully encapsulated the nutrients in the rubberwood cell cavities and successfully isolated the source of mildew nutrients, and has excellent mildew resistance performance. Example 8

[0062] S1) At room temperature, soak the de-greened and de-haired bamboo blocks (length × width × thickness: 50 mm × 20 mm × 5 mm) in 500 mL of deionized water, put them into a vacuum pressure impregnation tank, first perform vacuum impregnation at -0.08 MPa for 1 h, then perform pressure impregnation at 0.8 MPa for 3 h, and perform normal pressure impregnation for 24 h after pressure relief; S2) Take out the impregnated bamboo specimens, seal and wrap them, and place them in an electric heating forced air drying oven. First perform heat treatment at 60 °C for 8 h, and then perform heat treatment at 130 °C for 4 h.

[0063] The mildew resistance test method of the bamboo in this example is the same as that in Example 1. Mildew spots appeared on the obtained modified bamboo on the 3rd day, and the damage value of the specimen was 4 on the 30th day (the mildew resistance results are as Figure 1 、 Figure 2 shown).

[0064] The above is a further detailed description of the present invention, and it should not be regarded as a limitation to the specific implementation of the present invention. For those of ordinary skill in the technical field to which the present invention belongs, simple deductions or substitutions without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. An efficient method for preventing mildew and modifying wood and bamboo materials, characterized in that, The modification method comprises the following steps: S1) Prepare a mildew-proof modification liquid, which contains unsaturated organic acid monomers and a polymerization initiator; S2) Immerse the wood or bamboo in the mildew-proof modification liquid to allow the liquid to penetrate the wood or bamboo; S3) Take out the wood or bamboo after immersion is completed, and heat to initiate in-situ polymerization of the monomers to form polyorganic acids; S4) After the polymerization reaction is complete, further raise the temperature to cause the polyorganic acids to react with the wood or bamboo by esterification to obtain mildew-proof modified wood or bamboo.

2. The wood and bamboo anti-mildew modification method according to claim 1, wherein, The unsaturated organic acid monomers are selected from at least one of acrylic acid, crotonic acid, and methacrylic acid.

3. The method for preventing mildew and modifying wood and bamboo according to claim 1 or 2, characterized in that, The concentration of the unsaturated organic acid monomers is 1 to 5 wt%.

4. The wood and bamboo anti-mildew modification method according to claim 1, characterized in that, The polymerization initiator is selected from at least one of ammonium persulfate, potassium persulfate, hydrogen peroxide, and azodiisobutyramidine hydrochloride.

5. The method for preventing mildew and modifying wood and bamboo according to claim 1 or 4, characterized in that, The dosage of the polymerization initiator is 0.5 to 5% of the mass of the unsaturated organic acid monomers.

6. The wood and bamboo anti-mildew modification method according to claim 1, characterized in that, Heat the wood or bamboo to 50 to 90 °C to initiate in-situ polymerization of the monomers to form polyorganic acids; and / or the reaction time for in-situ polymerization of the monomers to form polyorganic acids is 1 to 12 hours.

7. The method for preventing mildew and modifying wood and bamboo according to claim 1, characterized in that, Raise the temperature to 100 to 160 °C to cause the polyorganic acids to react with the wood or bamboo by esterification; and / or the esterification reaction time is 1 to 6 hours.

8. The method for preventing mildew and modifying wood and bamboo according to claim 1, characterized in that, The bamboo is selected from Phyllostachys edulis, Dendrocalamus giganteus, Phyllostachys violascens, and Dendrocalamus latiflorus, and the wood is selected from Hevea brasiliensis.

9. The method for preventing mildew and modifying wood and bamboo according to claim 1, wherein, The immersion method is selected from one or more combinations of atmospheric pressure immersion, vacuum immersion, and pressure immersion.

10. An efficient mildew-proof modified wood and bamboo material, characterized in that, Prepared by the method according to any one of claims 1 to 9.

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