Waterproof multi-layer composite board containing melamine modified veneer and preparation method thereof

Abstract

The present invention provides a waterproof multi-layer composite board containing melamine modified veneer and a preparation method thereof, belonging to the technical field of composite material manufacturing; the preparation method comprises the following steps: preparing modified attapulgite; preparing a composite antibacterial agent; preparing a protective layer coating; preparing an epoxy modified derivative; and preparing a waterproof multi-layer composite board. The present invention first prepares an intermediate using 1-vinyl imidazole and 1-bromobutane as raw materials, then uses the intermediate to react with concentrated hydrochloric acid to prepare an antibacterial modifier, then uses a silane coupling agent to perform surface modification on zinc borate powder, and then, under the initiation of benzoyl peroxide, the antibacterial modifier is grafted on the surface of the zinc borate powder after surface modification to prepare a composite antibacterial agent, and after adding the composite antibacterial agent to the protective layer coating, the antibacterial effect of the protective layer coating can be improved, thereby improving the antibacterial performance of the waterproof multi-layer composite board.

Description

Technical Field

[0001] The invention relates to the technical field of composite material manufacturing, and in particular to a waterproof multi-layer composite board containing melamine modified veneer and a preparation method thereof. Background Art

[0002] With the development of society and the improvement of people's living standards, the requirements for building materials are getting higher and higher, especially in the field of interior decoration. People have put forward higher requirements on the safety, environmental protection and functionality of materials. Although traditional wood composite panels have good processing performance and aesthetics, they have obvious deficiencies in antibacterial, flame retardant and waterproof properties, and it is difficult to meet the needs of modern construction and decoration.

[0003] At present, common wood composite panels on the market mainly include ordinary plywood, particle board and medium-density fiberboard, etc. However, traditional wood composite panels are prone to absorb water and swell in a humid environment, causing deformation and damage, and are prone to breed bacteria and mold, which not only affects the service life but also causes harm to human health. In addition, the wood material itself is flammable. Although the flame retardant purpose can be achieved by coating the surface with flame retardants, traditional flame retardants are easily lost during use and cannot maintain the flame retardant effect for a long time.

[0004] Therefore, it is necessary to provide a waterproof multi-layer composite board containing melamine modified veneer and having both antibacterial and flame retardant effects and a preparation method thereof to extend its service life. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a waterproof multi-layer composite board containing melamine modified veneer and a preparation method thereof.

[0006] A waterproof multi-layer composite board containing melamine modified veneer, comprising: a core wood board, melamine modified veneer and a protective coating;

[0007] Among them, the raw material components of the protective layer coating that forms the protective coating include, by weight: 30-40 parts of polyvinyl chloride, 25-30 parts of methyl methacrylate, 38-42 parts of butyl acrylate, 50-60 parts of isooctyl acrylate, 20-25 parts of methoxyethyl acrylate, 58-62 parts of triisopropylsilyl acrylate, 2-4 parts of azobisisobutyronitrile, 180-220 parts of toluene, 1-2 parts of benzoyl peroxide, 20-30 parts of modified attapulgite and 14-18 parts of a composite antibacterial agent.

[0008] Furthermore, a method for preparing a waterproof multi-layer composite board containing melamine modified veneer comprises the following steps:

[0009] S1: Preparation of modified attapulgite

[0010] The attapulgite is activated, mixed with calcium oxide to prepare calcium-based attapulgite, dispersed in cyclohexane, and acrylic acid is added to react to obtain modified attapulgite;

[0011] S2: Preparation of composite antimicrobial agents

[0012] Firstly, 1-vinyl imidazole and 1-bromobutane are used as raw materials to prepare an intermediate, which is then reacted with concentrated hydrochloric acid to prepare an antibacterial modifier and prepared into liquid A, then zinc borate is surface-modified with a silane coupling agent and prepared into liquid B, and finally liquid A is added into liquid B for reaction to obtain a composite antibacterial agent;

[0013] S3: Preparation of protective coating

[0014] Add methyl methacrylate, butyl acrylate, isooctyl acrylate, methoxyethyl acrylate, triisopropylsilyl acrylate and azobisisobutyronitrile to toluene, heat and stir at 90-100° C. for 2-3 hours, then add benzoyl peroxide, keep warm and react for 2-3 hours, cool, add polyvinyl chloride, the modified attapulgite and the composite antibacterial agent, stir and mix evenly to obtain a protective layer coating;

[0015] S4: Preparation of epoxy-modified derivatives

[0016] Using hydrogenated rosin alcohol and acryloyl chloride as raw materials to prepare acrylic acid derivatives, and then using epichlorohydrin to react with the acrylic acid derivatives to obtain epoxy-modified derivatives;

[0017] S5: Preparation of waterproof multi-layer composite board

[0018] First, melamine modified veneer is prepared, and then urea-formaldehyde resin glue is applied on the surface of the wooden board, and the melamine modified veneer is attached. After hot pressing and curing, the surface is plasma treated and the above-mentioned epoxy modified derivative is coated. After the surface is cured, the above-mentioned protective layer coating is coated to form a protective coating to obtain a waterproof multi-layer composite board.

[0019] Furthermore, S1 specifically includes the following steps:

[0020] S1.1: Crush and grind the attapulgite, sieve it, and then add it into concentrated hydrochloric acid at a solid-liquid ratio of 1g:(6-8)mL, stir it for 30-40min, let it stand for sedimentation, and filter it to obtain activated attapulgite;

[0021] S1.2: Add the activated attapulgite and calcium oxide into deionized water at a solid-liquid ratio of 1 g: (3.5-4.5) g: (30-40) mL, heat and stir at 50-60° C. for 3-4 h, cool, filter, wash and dry to obtain calcium-based attapulgite;

[0022] S1.3: Add the above calcium-based attapulgite into cyclohexane at a solid-liquid ratio of 1g: (20-30)mL, ultrasonically disperse for 20-30min, heat to 70-80℃ and keep warm, then add acrylic acid and anhydrous ethanol while stirring, continue to keep warm and reflux for 3-4h, and obtain modified attapulgite after filtration, washing and drying.

[0023] Furthermore, S2 specifically includes the following steps:

[0024] S2.1: Add 1-vinylimidazole and 1-bromobutane into a reactor in a molar ratio of 1: (1.1-1.2), stir and mix evenly, then add tetrabutylammonium bromide, and heat under reflux at 80-100°C for 3-5h under a nitrogen atmosphere. After cooling, extract with ether, wash with water, strip, dry and distill under reduced pressure to obtain an intermediate;

[0025] S2.2: Place the intermediate in an ice water bath at 1-3°C, add concentrated hydrochloric acid to the intermediate, stir and react for 1-2h, concentrate under reduced pressure, wash with anhydrous ethanol and dry to obtain an antibacterial modifier, and dissolve the antibacterial modifier in deionized water at a solid-liquid ratio of 1g:(30-40)mL to obtain liquid A;

[0026] S2.3: Add zinc borate powder to 90% ethanol solution at a solid-liquid ratio of 1g: (100-120)mL, ultrasonically disperse for 20-30min, then add 1% by mass of silane coupling agent KH560, continue ultrasonically dispersing for 5-10min, and heat under reflux at 50-60℃ for 3-4h. After cooling, filter, wash, dry and grind to obtain surface-modified zinc borate powder;

[0027] S2.4: Add the surface-modified zinc borate powder to deionized water at a solid-liquid ratio of 1 g: (300-400) mL, and disperse by ultrasonic for 10-20 min to obtain liquid B;

[0028] S2.5: Add the above liquid A to liquid B in a volume ratio of 1:(3.5-4.5), then add 0.8% by mass fraction of benzoyl peroxide, heat and stir at 40-50°C for 6-8h, cool, filter, wash and dry to obtain a composite antibacterial agent.

[0029] Furthermore, S4 specifically includes the following steps:

[0030] S4.1: Add hydrogenated abietic alcohol, triethylamine and p-hydroxyanisole into tetrahydrofuran, stir thoroughly to dissolve, and obtain a mixed solution;

[0031] S4.2: Add acryloyl chloride to the mixed solution, heat and stir at 40-50°C for 4-5h, filter the precipitate, cool it, and remove the solvent by distillation under reduced pressure to obtain an acrylic acid derivative;

[0032] S4.3: Dissolve the above acrylic acid derivative in dichloromethane at a mass ratio of 1:(3-5), add epichlorohydrin and sodium hydroxide, heat and stir at 70-80°C to react for 5-6 hours, cool, wash with water and remove the solvent by reduced pressure distillation to obtain an epoxy-modified derivative.

[0033] Furthermore, S5 specifically includes the following steps:

[0034] S5.1: cutting and trimming the veneer raw materials and splicing them into rolls, and then immersing them in melamine glue for dipping treatment to obtain melamine modified veneer;

[0035] S5.2: evenly coating a layer of urea-formaldehyde resin glue on the surface of the wooden board, and then laminating the above-mentioned melamine-modified veneer on the urea-formaldehyde resin glue on the surface of the wooden board, and then putting it into a hot press, hot pressing, cooling and curing, to obtain a melamine-modified veneer board;

[0036] S5.3: Plasma treatment is performed on the surface of the melamine-modified veneer board, and a layer of epoxy-modified derivative obtained in step S4.3 is coated on the surface. After the surface is cured, a layer of protective coating is coated. After curing, a protective coating is formed to obtain a waterproof multi-layer composite board.

[0037] Furthermore, the volume ratio of acrylic acid, anhydrous ethanol and cyclohexane is 1:(0.8-1.2):(3-5).

[0038] Furthermore, the mass ratio of tetrabutylammonium bromide to 1-vinylimidazole is 1:(26-28), and the solid-liquid ratio of the intermediate to concentrated hydrochloric acid is 1 g:(0.6-0.8) mL.

[0039] Furthermore, the mass ratio of hydrogenated rosin alcohol, triethylamine, p-hydroxyanisole and tetrahydrofuran is (3-4):1:(0.006-0.008):(6.5-7.5), and the mass ratio of acryloyl chloride to hydrogenated rosin alcohol is (4.2-4.8):1.

[0040] Furthermore, the molar ratio of epichlorohydrin to the acrylic acid derivative is (3-4):1, and the molar ratio of sodium hydroxide to epichlorohydrin is (1-2):1.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] 1. The present invention first uses 1-vinyl imidazole and 1-bromobutane as raw materials to prepare an intermediate, then uses the intermediate to react with concentrated hydrochloric acid to prepare an antibacterial modifier, then uses a silane coupling agent to perform surface modification on zinc borate powder, and then under the initiation of benzoyl peroxide, the antibacterial modifier is grafted on the surface of the zinc borate powder after surface modification to prepare a composite antibacterial agent. After adding the composite antibacterial agent to a protective layer coating, on the one hand, since the antibacterial modifier molecules grafted on the surface of the zinc borate can form a protective layer, the zinc borate is prevented from agglomerating in the protective layer coating through a steric hindrance effect, so as to improve the dispersibility of the zinc borate. On the other hand, since zinc borate also has a certain antibacterial effect, when the antibacterial modifier is composited with zinc borate, the antibacterial effect of the protective layer coating can be further improved, thereby improving the antibacterial performance of the waterproof multi-layer composite board.

[0043] 2. The present invention prepares calcium-based attapulgite by first activating attapulgite and then dispersing it in deionized water with calcium oxide. The calcium-based attapulgite is then used as a raw material to react with acrylic acid for organic modification to improve the dispersibility of the attapulgite in the protective layer coating. Zinc borate decomposes at high temperature to produce boric acid, which can promote the formation of a dense carbon layer on the surface of the polymer to isolate oxygen and heat and prevent the spread of flames. The fibrous structure of attapulgite can form a network in the polymer matrix to reduce heat transfer. When the two are added to the protective layer coating together, the carbon layer promoted by zinc borate is combined with the network structure formed by attapulgite to form a denser and more stable carbon layer, which can more effectively isolate oxygen and heat, thereby effectively improving the flame retardant properties of the protective layer coating. In addition, zinc borate and modified attapulgite are not easy to be lost, which is beneficial to improving the long-term flame retardant effect of the waterproof multi-layer composite board.

[0044] 3. The present invention prepares acrylic acid derivatives by first using hydrogenated rosin alcohol and acryloyl chloride as raw materials, and then reacts the acrylic acid derivatives with epichlorohydrin to introduce epoxy groups into the acrylic acid derivative molecules to obtain epoxy-modified derivatives. After coating the epoxy-modified derivatives on the surface of melamine-modified veneer, on the one hand, the active functional groups on the epoxy-modified derivatives can covalently bond with melamine and the protective layer coating to form stable chemical bonds, thereby enhancing the interfacial bonding force between the protective layer coating and the melamine-modified veneer. On the other hand, since the epoxy-modified derivatives have good compatibility with both the melamine-modified veneer and the protective layer coating, the stress concentration at the interface can be reduced, thereby further improving the adhesion of the protective layer coating to the melamine-modified veneer. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0046] Figure 1 The present invention is a flowchart of a method for preparing a waterproof multi-layer composite board containing melamine modified veneer used in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] A waterproof multi-layer composite board containing melamine modified veneer and a preparation method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] A method for preparing a waterproof multi-layer composite board containing melamine modified veneer, such as Figure 1 As shown, the following steps are included:

[0050] S1: Preparation of modified attapulgite

[0051] S1.1: Crush and grind the attapulgite, sieve it, add it into concentrated hydrochloric acid at a solid-liquid ratio of 1g:6mL, stir it for 30min, let it stand for sedimentation, and filter it to obtain activated attapulgite;

[0052] S1.2: Add the activated attapulgite and calcium oxide into deionized water at a solid-liquid ratio of 1 g:3.5 g:30 mL, heat and stir at 50 °C for 3 h, and after cooling, filter, wash and dry to obtain calcium-based attapulgite;

[0053] S1.3: Add the calcium-based attapulgite to cyclohexane at a solid-liquid ratio of 1g:20mL, and after ultrasonic dispersion for 20min, heat to 70°C and keep warm, then add acrylic acid and anhydrous ethanol while stirring, and continue to keep warm and reflux for 3h, and obtain modified attapulgite after suction filtration, washing and drying, wherein the volume ratio of acrylic acid, anhydrous ethanol and cyclohexane is 1:0.8:3;

[0054] S2: Preparation of composite antimicrobial agents

[0055] S2.1: 1-vinylimidazole and 1-bromobutane are added into a reactor in a molar ratio of 1:1.1, stirred and mixed evenly, and then tetrabutylammonium bromide is added, and heated under reflux at 80°C for 3 hours under a nitrogen atmosphere. After cooling, the mixture is extracted with ether, washed with water, stripped, dried and distilled under reduced pressure to obtain an intermediate, wherein the mass ratio of tetrabutylammonium bromide to 1-vinylimidazole is 1:26;

[0056] S2.2: Place the intermediate in an ice water bath at 1°C, add concentrated hydrochloric acid to the intermediate, stir and react for 1 hour, concentrate under reduced pressure, wash with anhydrous ethanol and dry to obtain an antibacterial modifier, and dissolve the antibacterial modifier in deionized water at a solid-liquid ratio of 1g:30mL to obtain liquid A, wherein the solid-liquid ratio of the intermediate to concentrated hydrochloric acid is 1g:0.6mL;

[0057] S2.3: Add zinc borate powder to 90% ethanol solution at a solid-liquid ratio of 1g:100mL, ultrasonically disperse for 20min, then add 1% by mass of silane coupling agent KH560, continue ultrasonically dispersing for 5min, and heat to reflux at 50℃ for 3h. After cooling, filter, wash, dry and grind to obtain surface-modified zinc borate powder;

[0058] S2.4: Add the surface-modified zinc borate powder to deionized water at a solid-liquid ratio of 1 g:300 mL, and ultrasonically disperse for 10 min to obtain liquid B;

[0059] S2.5: Add the above-mentioned liquid A to liquid B at a volume ratio of 1:3.5, and then add 0.8% by mass fraction of benzoyl peroxide, heat and stir at 40°C for 6 hours, cool, filter, wash and dry to obtain a composite antibacterial agent;

[0060] S3: Preparation of protective coating

[0061] By weight, 25 parts of methyl methacrylate, 38 parts of butyl acrylate, 50 parts of isooctyl acrylate, 20 parts of methoxyethyl acrylate, 58 parts of triisopropylsilyl acrylate and 2 parts of azobisisobutyronitrile are added to 180 parts of toluene, heated and stirred at 90°C for 2 hours, and then 1 part of benzoyl peroxide is added, and the reaction is kept warm for 2 hours. After cooling, 30 parts of polyvinyl chloride, 20 parts of the above-mentioned modified attapulgite and 14 parts of the above-mentioned composite antibacterial agent are added, and the mixture is stirred and mixed uniformly to obtain a protective layer coating;

[0062] S4: Preparation of epoxy-modified derivatives

[0063] S4.1: adding hydrogenated abietic alcohol, triethylamine and p-hydroxyanisole to tetrahydrofuran, stirring and dissolving the mixture to obtain a mixed solution, wherein the mass ratio of hydrogenated abietic alcohol, triethylamine, p-hydroxyanisole and tetrahydrofuran is 3:1:0.006:6.5;

[0064] S4.2: Add acryloyl chloride to the mixed solution, heat and stir at 40°C for 4 hours, filter the precipitate, cool it, and remove the solvent by vacuum distillation to obtain an acrylic acid derivative, wherein the mass ratio of acryloyl chloride to hydrogenated rosin alcohol is 4.2:1;

[0065] S4.3: dissolving the acrylic acid derivative in dichloromethane at a mass ratio of 1:3, adding epichlorohydrin and sodium hydroxide, heating and stirring at 70°C for 5 hours, cooling, washing with water and removing the solvent by reduced pressure distillation to obtain an epoxy modified derivative, wherein the molar ratio of epichlorohydrin to the acrylic acid derivative is 3:1, and the molar ratio of sodium hydroxide to epichlorohydrin is 1:1;

[0066] S5: Preparation of waterproof multi-layer composite board

[0067] S5.1: cutting and trimming the veneer raw materials and splicing them into rolls, and then immersing them in melamine glue for dipping treatment to obtain melamine modified veneer;

[0068] S5.2: evenly coating a layer of urea-formaldehyde resin glue on the surface of the wooden board, and then laminating the above-mentioned melamine-modified veneer on the urea-formaldehyde resin glue on the surface of the wooden board, and then putting it into a hot press, hot pressing, cooling and curing, to obtain a melamine-modified veneer board;

[0069] S5.3: Plasma treatment is performed on the surface of the melamine-modified veneer board, and a layer of epoxy-modified derivative obtained in step S4.3 is coated on the surface. After the surface is cured, a layer of protective coating is coated. After curing, a protective coating is formed to obtain a waterproof multi-layer composite board.

[0070] Example 2

[0071] A method for preparing a waterproof multi-layer composite board containing melamine modified veneer, such as Figure 1 As shown, the following steps are included:

[0072] S1: Preparation of modified attapulgite

[0073] S1.1: Crush and grind the attapulgite, sieve it, add it into concentrated hydrochloric acid at a solid-liquid ratio of 1g:7mL, stir it for 35min, let it stand for sedimentation, and filter it to obtain activated attapulgite;

[0074] S1.2: Add the activated attapulgite and calcium oxide into deionized water at a solid-liquid ratio of 1g:4g:35mL, heat and stir at 55°C for 3.5h, cool, filter, wash and dry to obtain calcium-based attapulgite;

[0075] S1.3: Add the calcium-based attapulgite to cyclohexane at a solid-liquid ratio of 1g:25mL, and after ultrasonic dispersion for 25min, heat to 75°C and keep warm, then add acrylic acid and anhydrous ethanol while stirring, and continue to keep warm and reflux for 3.5h. After suction filtration, washing and drying, modified attapulgite is obtained, wherein the volume ratio of acrylic acid, anhydrous ethanol and cyclohexane is 1:1:4;

[0076] S2: Preparation of composite antimicrobial agents

[0077] S2.1: 1-vinylimidazole and 1-bromobutane are added into a reactor at a molar ratio of 1:1.15, stirred and mixed evenly, and then tetrabutylammonium bromide is added, and heated under reflux at 90°C for 4 hours under a nitrogen atmosphere. After cooling, the mixture is extracted with ether, washed with water, stripped, dried and distilled under reduced pressure to obtain an intermediate, wherein the mass ratio of tetrabutylammonium bromide to 1-vinylimidazole is 1:27;

[0078] S2.2: Place the intermediate in an ice water bath at 2°C, add concentrated hydrochloric acid to the intermediate, stir and react for 1.5 hours, concentrate under reduced pressure, wash with anhydrous ethanol and dry to obtain an antibacterial modifier, and dissolve the antibacterial modifier in deionized water at a solid-liquid ratio of 1g:35mL to obtain liquid A, wherein the solid-liquid ratio of the intermediate to concentrated hydrochloric acid is 1g:0.7mL;

[0079] S2.3: Add zinc borate powder to 90% ethanol solution at a solid-liquid ratio of 1g:110mL, ultrasonically disperse for 25 minutes, then add 1% by mass of silane coupling agent KH560, continue ultrasonically dispersing for 7.5 minutes, and heat to reflux at 55°C for 3.5 hours. After cooling, filter, wash, dry and grind to obtain surface-modified zinc borate powder;

[0080] S2.4: Add the surface-modified zinc borate powder to deionized water at a solid-liquid ratio of 1 g:350 mL, and disperse by ultrasonic for 15 min to obtain liquid B;

[0081] S2.5: Add the above-mentioned liquid A to liquid B at a volume ratio of 1:4, and then add 0.8% by mass fraction of benzoyl peroxide, heat and stir at 45°C for 7 hours, cool, filter, wash and dry to obtain a composite antibacterial agent;

[0082] S3: Preparation of protective coating

[0083] By weight, 28 parts of methyl methacrylate, 40 parts of butyl acrylate, 55 parts of isooctyl acrylate, 23 parts of methoxyethyl acrylate, 60 parts of triisopropylsilyl acrylate and 3 parts of azobisisobutyronitrile are added to 200 parts of toluene, heated and stirred at 95°C for 2.5 hours, and then 1 part of benzoyl peroxide is added, and the reaction is kept warm for 2.5 hours. After cooling, 35 parts of polyvinyl chloride, 25 parts of the above-mentioned modified attapulgite and 16 parts of the above-mentioned composite antibacterial agent are added, and the mixture is stirred and mixed uniformly to obtain a protective layer coating;

[0084] S4: Preparation of epoxy-modified derivatives

[0085] S4.1: adding hydrogenated abietic alcohol, triethylamine and p-hydroxyanisole to tetrahydrofuran, stirring and dissolving the mixture to obtain a mixed solution, wherein the mass ratio of hydrogenated abietic alcohol, triethylamine, p-hydroxyanisole and tetrahydrofuran is 3.5:1:0.007:7;

[0086] S4.2: Add acryloyl chloride to the mixed solution, heat and stir at 45°C to react for 4.5 hours, filter the precipitate, cool it, and remove the solvent by vacuum distillation to obtain an acrylic acid derivative, wherein the mass ratio of acryloyl chloride to hydrogenated rosin alcohol is 4.5:1;

[0087] S4.3: dissolving the acrylic acid derivative in dichloromethane at a mass ratio of 1:4, adding epichlorohydrin and sodium hydroxide, heating and stirring at 75°C for 5.5 hours, cooling, washing with water and removing the solvent by reduced pressure distillation to obtain an epoxy modified derivative, wherein the molar ratio of epichlorohydrin to the acrylic acid derivative is 3.5:1, and the molar ratio of sodium hydroxide to epichlorohydrin is 1.5:1;

[0088] S5: Preparation of waterproof multi-layer composite board

[0089] S5.1: cutting and trimming the veneer raw materials and splicing them into rolls, and then immersing them in melamine glue for dipping treatment to obtain melamine modified veneer;

[0090] S5.2: evenly coating a layer of urea-formaldehyde resin glue on the surface of the wooden board, and then laminating the above-mentioned melamine-modified veneer on the urea-formaldehyde resin glue on the surface of the wooden board, and then putting it into a hot press, hot pressing, cooling and curing, to obtain a melamine-modified veneer board;

[0091] S5.3: Plasma treatment is performed on the surface of the melamine-modified veneer board, and a layer of epoxy-modified derivative obtained in step S4.3 is coated on the surface. After the surface is cured, a layer of protective coating is coated. After curing, a protective coating is formed to obtain a waterproof multi-layer composite board.

[0092] Example 3

[0093] A method for preparing a waterproof multi-layer composite board containing melamine modified veneer, such as Figure 1 As shown, the following steps are included:

[0094] S1: Preparation of modified attapulgite

[0095] S1.1: Crush and grind the attapulgite, sieve it, add it into concentrated hydrochloric acid at a solid-liquid ratio of 1g:8mL, stir it for 40min, let it stand for sedimentation, and filter it to obtain activated attapulgite;

[0096] S1.2: Add the above activated attapulgite and calcium oxide into deionized water at a solid-liquid ratio of 1g:4.5g:40mL, heat and stir at 60°C for 4h, cool, filter, wash and dry to obtain calcium-based attapulgite;

[0097] S1.3: Add the calcium-based attapulgite to cyclohexane at a solid-liquid ratio of 1g:30mL, and after ultrasonic dispersion for 30 minutes, heat to 80°C and keep warm, then add acrylic acid and anhydrous ethanol while stirring, and continue to keep warm and reflux for 4 hours. After suction filtration, washing and drying, modified attapulgite is obtained, wherein the volume ratio of acrylic acid, anhydrous ethanol and cyclohexane is 1:1.2:5;

[0098] S2: Preparation of composite antimicrobial agents

[0099] S2.1: 1-vinylimidazole and 1-bromobutane are added into a reactor in a molar ratio of 1:1.2, stirred and mixed evenly, and then tetrabutylammonium bromide is added, and heated under reflux at 100°C for 5 hours under a nitrogen atmosphere. After cooling, the mixture is extracted with ether, washed with water, stripped, dried and distilled under reduced pressure to obtain an intermediate, wherein the mass ratio of tetrabutylammonium bromide to 1-vinylimidazole is 1:28;

[0100] S2.2: Place the intermediate in an ice water bath at 3°C, add concentrated hydrochloric acid to the intermediate, stir and react for 2 hours, concentrate under reduced pressure, wash with anhydrous ethanol and dry to obtain an antibacterial modifier, and dissolve the antibacterial modifier in deionized water at a solid-liquid ratio of 1g:40mL to obtain liquid A, wherein the solid-liquid ratio of the intermediate to concentrated hydrochloric acid is 1g:0.8mL;

[0101] S2.3: Add zinc borate powder to 90% ethanol solution at a solid-liquid ratio of 1g:120mL, ultrasonically disperse for 30 minutes, then add 1% by mass of silane coupling agent KH560, continue ultrasonically dispersing for 10 minutes, and heat under reflux at 60°C for 4 hours. After cooling, filter, wash, dry and grind to obtain surface-modified zinc borate powder;

[0102] S2.4: Add the surface-modified zinc borate powder to deionized water at a solid-liquid ratio of 1 g:400 mL, and disperse by ultrasonic for 20 min to obtain liquid B;

[0103] S2.5: Add the above-mentioned liquid A to liquid B at a volume ratio of 1:4.5, and then add 0.8% by mass fraction of benzoyl peroxide, heat and stir at 50°C for 8 hours, cool, filter, wash and dry to obtain a composite antibacterial agent;

[0104] S3: Preparation of protective coating

[0105] By weight, 30 parts of methyl methacrylate, 42 parts of butyl acrylate, 60 parts of isooctyl acrylate, 25 parts of methoxyethyl acrylate, 62 parts of triisopropylsilyl acrylate and 4 parts of azobisisobutyronitrile are added to 220 parts of toluene, heated and stirred at 100°C for 3 hours, and then 2 parts of benzoyl peroxide are added, and the reaction is kept warm for 3 hours. After cooling, 40 parts of polyvinyl chloride, 30 parts of the above-mentioned modified attapulgite and 18 parts of the above-mentioned composite antibacterial agent are added, and the mixture is stirred and mixed uniformly to obtain a protective layer coating;

[0106] S4: Preparation of epoxy-modified derivatives

[0107] S4.1: adding hydrogenated abietic alcohol, triethylamine and p-hydroxyanisole to tetrahydrofuran, stirring and dissolving the mixture to obtain a mixed solution, wherein the mass ratio of hydrogenated abietic alcohol, triethylamine, p-hydroxyanisole and tetrahydrofuran is 4:1:0.008:7.5;

[0108] S4.2: Add acryloyl chloride to the mixed solution, heat and stir at 50°C for 5 hours, filter the precipitate, cool it, and remove the solvent by vacuum distillation to obtain an acrylic acid derivative, wherein the mass ratio of acryloyl chloride to hydrogenated rosin alcohol is 4.8:1;

[0109] S4.3: dissolving the acrylic acid derivative in dichloromethane at a mass ratio of 1:5, adding epichlorohydrin and sodium hydroxide, heating and stirring at 80°C for 6 hours, cooling, washing with water and removing the solvent by reduced pressure distillation to obtain an epoxy modified derivative, wherein the molar ratio of epichlorohydrin to the acrylic acid derivative is 4:1, and the molar ratio of sodium hydroxide to epichlorohydrin is 2:1;

[0110] S5: Preparation of waterproof multi-layer composite board

[0111] S5.1: cutting and trimming the veneer raw materials and splicing them into rolls, and then immersing them in melamine glue for dipping treatment to obtain melamine modified veneer;

[0112] S5.2: evenly coating a layer of urea-formaldehyde resin glue on the surface of the wooden board, and then laminating the above-mentioned melamine-modified veneer on the urea-formaldehyde resin glue on the surface of the wooden board, and then putting it into a hot press, hot pressing, cooling and curing, to obtain a melamine-modified veneer board;

[0113] S5.3: Plasma treatment is performed on the surface of the melamine-modified veneer board, and a layer of epoxy-modified derivative obtained in step S4.3 is coated on the surface. After the surface is cured, a layer of protective coating is coated. After curing, a protective coating is formed to obtain a waterproof multi-layer composite board.

[0114] Comparative Example 1

[0115] The difference between Comparative Example 1 and Example 1 is that the composite antibacterial agent in step S3 is replaced by an equal amount of zinc borate powder.

[0116] Comparative Example 2

[0117] The difference between Comparative Example 2 and Example 1 is that the composite antibacterial agent in step S3 is replaced by an equal amount of the antibacterial modifier prepared in step S2.2.

[0118] Comparative Example 3

[0119] The difference between Comparative Example 3 and Example 1 is that the composite antibacterial agent in step S3 is replaced by an equal amount of modified attapulgite.

[0120] Comparative Example 4

[0121] The difference between this comparative example 4 and example 1 is that the modified attapulgite in step S3 is replaced by an equal amount of the composite antibacterial agent.

[0122] Comparative Example 5

[0123] The difference between this comparative example 5 and example 1 is that the modified attapulgite in step S3 is replaced by an equal amount of attapulgite, that is, the attapulgite is not modified.

[0124] Comparative Example 6

[0125] The difference between Comparative Example 6 and Example 1 is that the step of coating the epoxy-modified derivative in step S5.3 is removed, that is, a protective layer coating is directly coated after the plasma treatment.

[0126] Test Case

[0127] Test 1: The 60d water absorption of the protective coating of the waterproof multi-layer composite board prepared in Examples 1-3 was measured with reference to HG / T3344-2012 "Determination of Water Absorption of Paint Films". The results are shown in Table 1.

[0128] Table 1: Comparison of water absorption test results of protective coatings of waterproof multi-layer composite panels

[0129] Example 1 Example 2 Example 3 Water absorption (%) 1.09 1.11 1.08

[0130] It can be seen from Table 1 that the water absorption rates of the protective coatings of the waterproof multi-layer composite panels prepared in Examples 1-3 are approximately 1.09%, 1.11% and 1.08%, respectively. It can be seen that the water absorption rates of the protective coatings of the waterproof multi-layer composite panels prepared in Examples 1-3 are very low, that is, the waterproof multi-layer composite panels of the present invention have excellent waterproof properties.

[0131] Test 2: Referring to GB / T21866-2008 "Determination of antibacterial properties and antibacterial effects of antibacterial coatings (paint films)", the antibacterial properties of the protective coatings of the waterproof multi-layer composite panels prepared in Examples 1-3 and Comparative Examples 1-2, as well as the antibacterial properties after wiping with water 50 times, were determined using the flat plate coating counting method. The results are shown in Table 2.

[0132] Table 2: Comparison of antibacterial performance test results of protective coatings for waterproof multi-layer composite panels

[0133] Antibacterial rate (%) Antibacterial rate after wiping 50 times (%) Example 1 96.3 95.6 Example 2 96.5 95.9 Example 3 96.0 95.5 Comparative Example 1 69.2 60.8 Comparative Example 2 38.7 23.2

[0134] It can be seen from Table 2 that after the composite antibacterial agent in Comparative Example 1 and Comparative Example 2 was replaced with an equal amount of zinc borate powder and an antibacterial modifier, respectively, the antibacterial rate of the protective coating of the waterproof multi-layer composite board obtained was much lower than that in Example 1. It can be seen that the combination of zinc borate powder and antibacterial modifier has a synergistic antibacterial effect, which can further improve the antibacterial performance of the waterproof multi-layer composite board. Moreover, since the antibacterial rate of the protective coating of the waterproof multi-layer composite board prepared in Examples 1-3 was only slightly reduced after being wiped with water 50 times, it is shown that the waterproof multi-layer composite board of the present invention has good antibacterial durability.

[0135] Test 3: Referring to GB / T2406.2-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method", an oxygen index meter was used to test the initial limiting oxygen index of the waterproof multi-layer composite panels prepared in Examples 1-3 and Comparative Examples 3-4, as well as the limiting oxygen index after heat treatment at 60°C for 15 days. The results are shown in Table 3.

[0136] Table 3: Comparison of Limiting Oxygen Index Test Results of Waterproof Multilayer Composite Panels

[0137] Initial LOI (%) LOI after 15 days of heat treatment (%) Example 1 34.8 34.5 Example 2 34.8 34.4 Example 3 34.9 34.5 Comparative Example 3 28.2 27.7 Comparative Example 4 26.5 25.9 Comparative Example 5 28.7 28.3

[0138] It can be seen from Table 3 that when a single modified attapulgite or a single composite antibacterial agent is used in Comparative Examples 3 and 4, the limiting oxygen index of the obtained waterproof multi-layer composite board is lower than that in Example 1. It can be seen that when the modified attapulgite and the composite antibacterial agent are used in combination, there is a synergistic effect, which can further improve the flame retardant properties of the waterproof multi-layer composite board. Moreover, when the attapulgite is not modified in Comparative Example 5, the initial LOI of the obtained waterproof multi-layer composite board is lower than that in Example 1. It can be seen that modifying the attapulgite can improve its dispersibility in the protective layer coating and prevent the attapulgite from agglomerating, thereby achieving the purpose of improving the flame retardant effect.

[0139] Test 4: Referring to the evaluation standard of GB / T9286-1998 "Scratch test of paint and varnish film", the adhesion of the protective coating of the waterproof multi-layer composite board prepared in Examples 1-3 and Comparative Example 6 was evaluated. The results are shown in Table 4.

[0140] Table 4: Comparison of test results of protective coating adhesion of waterproof multi-layer composite panels

[0141] Example 1 Example 2 Example 3 Comparative Example 6 Adhesion Level 0 Level 0 Level 0 Level 2

[0142] It can be seen from Table 4 that when no epoxy modified derivative layer is prepared between the melamine modified veneer and the protective coating in Comparative Example 6, the adhesion of the protective coating is level 2, which is poorer than that in Example 1. It can be seen that the introduction of the epoxy modified derivative layer can effectively improve the adhesion of the protective coating to the melamine modified veneer.

[0143] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a waterproof multi-layer composite board containing melamine modified veneer, characterized in that: The steps include: S1: Preparation of modified attapulgite The attapulgite is activated, mixed with calcium oxide to prepare calcium-based attapulgite, dispersed in cyclohexane, and acrylic acid is added to react to obtain modified attapulgite; S2: Preparation of composite antimicrobial agents Firstly, 1-vinyl imidazole and 1-bromobutane are used as raw materials to prepare an intermediate, which is then reacted with concentrated hydrochloric acid to prepare an antibacterial modifier and prepared into liquid A, then zinc borate is surface-modified with a silane coupling agent and prepared into liquid B, and finally liquid A is added into liquid B for reaction to obtain a composite antibacterial agent; S3: Preparation of protective coating Add methyl methacrylate, butyl acrylate, isooctyl acrylate, methoxyethyl acrylate, triisopropylsilyl acrylate and azobisisobutyronitrile to toluene, heat and stir at 90-100° C. for 2-3 hours, then add benzoyl peroxide, keep warm and react for 2-3 hours, cool, add polyvinyl chloride, the modified attapulgite and the composite antibacterial agent, stir and mix evenly to obtain a protective layer coating; S4: Preparation of epoxy-modified derivatives S4.1: Add hydrogenated abietic alcohol, triethylamine and p-hydroxyanisole into tetrahydrofuran, stir thoroughly to dissolve, and obtain a mixed solution; S4.2: Add acryloyl chloride to the mixed solution, heat and stir at 40-50°C for 4-5h, filter the precipitate, cool it, and remove the solvent by vacuum distillation to obtain an acrylic acid derivative; S4.3: dissolving the acrylic acid derivative in dichloromethane at a mass ratio of 1:(3-5), adding epichlorohydrin and sodium hydroxide, heating and stirring at 70-80°C for 5-6h, cooling, washing with water and removing the solvent by distillation under reduced pressure to obtain an epoxy-modified derivative; S5: Preparation of waterproof multi-layer composite board First, melamine modified veneer is prepared, then urea-formaldehyde resin glue is applied on the surface of the wood board, and the melamine modified veneer is attached, hot pressing and curing are performed, and then surface plasma treatment is performed, and the epoxy modified derivative is coated, and after the surface is cured, the protective layer coating is coated to form a protective coating to obtain a waterproof multi-layer composite board; The waterproof multi-layer composite board comprises: a core wood board, a melamine modified veneer and a protective coating; Among them, the raw material components of the protective layer coating that forms the protective coating include, by weight: 30-40 parts of polyvinyl chloride, 25-30 parts of methyl methacrylate, 38-42 parts of butyl acrylate, 50-60 parts of isooctyl acrylate, 20-25 parts of methoxyethyl acrylate, 58-62 parts of triisopropylsilyl acrylate, 2-4 parts of azobisisobutyronitrile, 180-220 parts of toluene, 1-2 parts of benzoyl peroxide, 20-30 parts of modified attapulgite and 14-18 parts of a composite antibacterial agent.

2. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 1, characterized in that: S1 specifically includes the following steps: S1.1: Crush and grind the attapulgite, sieve it, and then add it to concentrated hydrochloric acid at a solid-liquid ratio of 1g:(6-8)mL, stir it for 30-40min, let it stand for sedimentation, and filter it to obtain activated attapulgite; S1.2: Add the activated attapulgite and calcium oxide into deionized water at a solid-liquid ratio of 1 g: (3.5-4.5) g: (30-40) mL, heat and stir at 50-60° C. for 3-4 h, cool, filter, wash and dry to obtain calcium-based attapulgite; S1.3: Add the above calcium-based attapulgite into cyclohexane at a solid-liquid ratio of 1g:(20-30)mL, ultrasonically disperse for 20-30min, heat to 70-80℃ and keep warm, then add acrylic acid and anhydrous ethanol while stirring, continue to keep warm and reflux for 3-4h, filter, wash and dry to obtain modified attapulgite.

3. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 2, characterized in that: S2 specifically includes the following steps: S2.1: Add 1-vinylimidazole and 1-bromobutane into a reactor in a molar ratio of 1:(1.1-1.2), stir and mix evenly, then add tetrabutylammonium bromide, and heat under reflux at 80-100°C for 3-5h in a nitrogen atmosphere. After cooling, extract with ether, wash with water, strip, dry and distill under reduced pressure to obtain an intermediate; S2.2: Place the above intermediate in an ice-water bath at 1-3°C, then add concentrated hydrochloric acid to the intermediate, stir and react for 1-2h, concentrate under reduced pressure, wash with anhydrous ethanol and dry to obtain an antibacterial modifier, and dissolve the antibacterial modifier in deionized water at a solid-liquid ratio of 1g:(30-40)mL to obtain liquid A; S2.3: Add zinc borate powder to 90% ethanol solution at a solid-liquid ratio of 1 g: (100-120) mL, ultrasonically disperse for 20-30 min, then add 1% by mass of silane coupling agent KH560, continue ultrasonically dispersing for 5-10 min, and heat under reflux at 50-60° C. for 3-4 h. After cooling, filter, wash, dry and grind to obtain surface-modified zinc borate powder; S2.4: Add the surface-modified zinc borate powder to deionized water at a solid-liquid ratio of 1 g: (300-400) mL, and disperse by ultrasonic for 10-20 min to obtain liquid B; S2.5: Add the above-mentioned liquid A to liquid B in a volume ratio of 1:(3.5-4.5), and then add 0.8% by mass fraction of benzoyl peroxide, heat and stir at 40-50°C to react for 6-8h, and after cooling, filter, wash and dry to obtain a composite antibacterial agent.

4. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 3, characterized in that: S5 includes the following steps: S5.1: cutting and trimming the veneer raw materials and splicing them into rolls, and then immersing them in melamine glue for dipping treatment to obtain melamine modified veneer; S5.2: evenly coating a layer of urea-formaldehyde resin glue on the surface of the wooden board, and then laminating the above-mentioned melamine-modified veneer on the urea-formaldehyde resin glue on the surface of the wooden board, and then putting it into a hot press, hot pressing, cooling and curing, to obtain a melamine-modified veneer board; S5.3: Plasma treatment is performed on the surface of the melamine-modified veneer board, and a layer of epoxy-modified derivative obtained in step S4.3 is coated on the surface. After the surface is cured, a layer of protective coating is coated. After curing, a protective coating is formed to obtain a waterproof multi-layer composite board.

5. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 2, characterized in that: The volume ratio of acrylic acid, anhydrous ethanol and cyclohexane is 1: (0.8-1.2): (3-5)。 6. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 3, characterized in that: The mass ratio of tetrabutylammonium bromide to 1-vinylimidazole is 1:(26-28), and the solid-liquid ratio of the intermediate to concentrated hydrochloric acid is 1 g:(0.6-0.8) mL.

7. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 1, characterized in that: The mass ratio of hydrogenated abietic alcohol, triethylamine, p-hydroxyanisole and tetrahydrofuran is (3-4):1:(0.006-0.008):(6.5-7.5), and the mass ratio of acryloyl chloride to hydrogenated abietic alcohol is (4.2-4.8):

1.

8. The method for preparing a waterproof multi-layer composite board containing melamine modified veneer according to claim 1, characterized in that: The molar ratio of epichlorohydrin to the acrylic acid derivative is (3-4):1, and the molar ratio of sodium hydroxide to epichlorohydrin is (1-2):1.

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