High-strength stain-resistant melamine veneer and preparation method thereof

Abstract

The invention discloses a high-strength stain-resistant melamine veneer and a preparation method thereof, and belongs to the technical field of veneer preparation. The preparation method of the high-strength stain-resistant melamine veneer comprises the following steps: step 1, adding melamine and a nano reinforcing agent into distilled water, uniformly stirring and mixing to obtain a mixed emulsion, putting impregnated paper into the mixed emulsion, soaking, and taking out to obtain composite impregnated paper; 2, a hard fiberboard is selected as a base material, the composite impregnated paper is flatly placed on the surface of the base material, then the base material is placed on a pressing machine, hot pressing and cooling are conducted, and a melamine-containing veneer is obtained; and 3, the surface of the melamine veneer is sprayed with a stain-resistant coating, drying is conducted, and the high-strength stain-resistant melamine veneer is obtained. The veneer prepared by the method has excellent strength and stain resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of decorative panel preparation, and particularly relates to a melamine decorative panel with high strength and stain resistance and a preparation method thereof. Background Art

[0002] Melamine decorative panels, as important decorative materials in the fields of modern furniture manufacturing and interior decoration, their research and optimization have always centered around solving the core problems of insufficient strength and poor stain resistance commonly existing in traditional boards. Although traditional melamine decorative panels occupy an important position in the market with rich pattern choices, good processing performance, and relatively low costs, the deficiencies in strength and stain resistance exposed during long-term use have become bottlenecks restricting their further development.

[0003] Patent CN103526895A discloses a method for manufacturing a high-strength scratch-resistant fireproof decorative panel. Aiming at the problems of easy cracking, easy curling, and scratch susceptibility of decorative panels widely used in building materials in the prior art, it provides a method for manufacturing a high-strength scratch-resistant fireproof decorative panel: selecting a special-grade solid wood fireproof veneer or an E1-grade fireproof high-density board as the bottom layer, selecting a melamine impregnated paper as the middle layer, and selecting aluminum oxide as the surface layer, and hot-pressing and forming through a cold-hot-cold hot-pressing process using a hot press. The effects of preventing cracking, curling, deformation, scratching, and fireproofing are achieved. However, there is still room for improvement in the strength and stain resistance of the decorative panel prepared by this method. Summary of the Invention

[0004] The purpose of the present invention is to provide a melamine decorative panel with high strength and stain resistance and a preparation method thereof, which are used to solve the technical problems of poor mechanical properties and stain resistance of decorative panels in the prior art.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a preparation method for a melamine decorative panel with high strength and stain resistance, including the following steps:

[0007] Step 1: Add melamine and a nano-enhancer to distilled water, stir and mix evenly to obtain a mixed emulsion, place the impregnated paper into the mixed emulsion, soak it, and then take it out to obtain a composite impregnated paper;

[0008] Step 2: Select a hard fiberboard as the substrate, place the composite impregnated paper flat on the surface of the substrate, then place it on a press, hot-press it, and cool it to obtain a melamine decorative panel-containing product;

[0009] Step 3: Spray a stain-resistant coating on the surface of the melamine decorative panel, and dry it to obtain a melamine decorative panel with high strength and stain resistance.

[0010] Preferably, in the first step, the dosage ratio of melamine, nano-enhancer and distilled water is (4-6) g : (1-3) g : (250-280) mL, the stirring and mixing time is 2-3 h, and the soaking time is 8-12 h; in the second step, a hot pressing method with a high temperature for a short period and a low temperature for a long period is adopted, the set pressure is 2-3 MPa, the temperature is 160-200 °C, and the hot pressing time is 30-60 s for each sheet; in the third step, the drying temperature is 45-55 °C and the time is 18-24 h.

[0011] Preferably, the preparation method of the nano-enhancer includes the following steps:

[0012] Q1: Add cellulose nanocrystals to a container filled with dimethyl sulfoxide, then add L-lactide, heat under a nitrogen atmosphere, then add stannous octoate, react, after the reaction ends, precipitate, centrifuge, wash, and vacuum dry to obtain a composite;

[0013] Q2: Mix and stir calcium chloride and ammonia water, then add distilled water to obtain a mixed solution. Subsequently, mix and stir the mixed solution, cetyltrimethylammonium bromide, n-butanol and cyclohexane, and add sucrose during the mixing and stirring process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion and continuously stir and react. Stop passing carbon dioxide when no more precipitation occurs, let it stand for aging, wash, centrifuge, and dry to obtain nanoparticles; Add the composite and nanoparticles to a container filled with a mixed solution of chloroform and petroleum ether, stir and mix, then let it stand, dry, and ball mill to obtain the nano-enhancer.

[0014] In the above process, cellulose nanocrystals and L-lactide undergo a polymerization reaction in dimethyl sulfoxide. Subsequently, using stannous octoate as a catalyst, L-lactide undergoes ring-opening polymerization reaction to increase the molecular chain of L-lactide and obtain a composite; Subsequently, using calcium chloride, ammonia water and sucrose as raw materials, under the action of carbon dioxide, nanoparticles are prepared, and then the composite and nanoparticles are mixed to prepare the nano-enhancer.

[0015] Preferably, in Q1, the dosage ratio of cellulose nanocrystals, dimethyl sulfoxide, L-lactide and stannous octoate is (0.3-0.5) g : (8-12) mL : (9-15) g : (0.09-0.15) g. When the system temperature is 128-135 °C, add stannous octoate, the reaction time is 18-24 h, add methanol for precipitation, the centrifugation speed is 8000-12000 rpm, the time is 8-12 min, wash with methanol and chloroform, and the vacuum drying temperature is 40-50 °C and the time is 24-36 h.

[0016] Preferably, in Q2, the dosage ratio of calcium chloride, ammonia water and distilled water is (1.23 - 1.62) g : (0.9 - 1.2) g : (10 - 12) mL, the volume ratio of the mixed solution, cetyltrimethylammonium bromide, n-butanol and cyclohexane is (2 - 4) : (50 - 75) : (8 - 14) : (15 - 25), the flow rate of carbon dioxide introduced is 300 mL / min, the static aging time is 12 - 15 h, washed with ethanol, the drying temperature is 70 - 80 °C, and the time is 24 - 32 h; the dosage ratio of the complex, nanoparticles, chloroform and petroleum ether is (3 - 5) g : (1 - 1.2) g : (6 - 8) mL : (4 - 6) mL, the mixing and stirring time is 20 - 24 h, the drying temperature is 35 - 38 °C, and the time is 32 - 36 h.

[0017] Preferably, the preparation method of the stain-resistant coating comprises the following steps:

[0018] S1: Add perfluoropolyether carboxylic acid and fluorocarbon solvent into a container, then drop in pyridine, after heating and stirring, drop in thionyl chloride, continue stirring, after the stirring ends, perform reduced-pressure distillation, add pentaerythritol triacrylate, and heat for reaction to obtain Compound 1;

[0019] S2: Add magnesium powder, methyltriethoxysilane, iodine powder and tetrahydrofuran into a container, introduce nitrogen, heat up in an oil bath, then drop 4-bromo-2-fluoro-1-trifluorovinyloxybenzene into the container through a constant-pressure dropping funnel, after the dropping is completed, stir, then cool, distill, add n-hexane for extraction, filter, distill and concentrate, and perform reduced-pressure distillation to obtain Compound 2;

[0020] S3: Add Compound 1 and fluorocarbon solvent into a container, then add Compound 2, after stirring and reacting, continue heating for reaction, then cool down to room temperature, wash, dissolve, and separate the layers to obtain the stain-resistant coating.

[0021] In the above process, using perfluoropolyether carboxylic acid as a raw material, it undergoes a substitution reaction with thionyl chloride, and then continues to undergo a substitution reaction with pentaerythritol triacrylate to prepare Compound 1. Then, using methyltriethoxysilane and 4-bromo-2-fluoro-1-trifluorovinyloxybenzene as raw materials, an addition reaction occurs to prepare Compound 2. Subsequently, Compound 1 reacts with Compound 2 to prepare the stain-resistant coating. Among them, the synthesis reaction formula of the stain-resistant coating is as follows:

[0022]

[0023] Preferably, in the step S1, the dosage ratio of perfluoropolyether carboxylic acid, fluorocarbon solvent, pyridine, thionyl chloride and pentaerythritol triacrylate is (3 - 5) g : (3 - 5) mL : (0.19 - 0.21) mL : (2 - 3) mL : (0.2 - 0.3) g. The temperature for heating and stirring is 70 - 74 °C, the stirring time is 10 - 14 min, the continuous stirring time is 6 - 10 h, the heating reaction temperature is 45 - 55 °C, and the time is 24 - 28 h.

[0024] Preferably, in the step S2, the dosage ratio of magnesium powder, methyltriethoxysilane, iodine powder, tetrahydrofuran and 4 - bromo - 2 - fluoro - 1 - trifluorovinyloxybenzene is (4.2 - 4.6) g : (37.11 - 37.45) g : (0.1 - 0.12) g : (200 - 250) mL : (38 - 45) g. The temperature for heating in the oil bath is 60 - 70 °C, and the stirring time is 20 - 24 h.

[0025] Preferably, in the step S3, the dosage ratio of Compound 1, fluorocarbon solvent and Compound 2 is (2 - 4) g : (2 - 5) mL : (0.4 - 0.6) g. The stirring reaction time is 30 - 45 min, the temperature for heating and reaction is 50 - 60 °C, and the reaction time is 10 - 12 h.

[0026] Preferably, the high - strength stain - resistant melamine decorative panel is prepared by the method according to any one of claims 1 - 9.

[0027] In summary, due to the adoption of the above - mentioned technical solution, the beneficial effects of the present invention are as follows:

[0028] 1. The present invention first uses cellulose nanocrystals, L - lactide, calcium chloride, ammonia water and sucrose as raw materials to prepare a nano - enhancer. Subsequently, perfluoropolyether carboxylic acid, thionyl chloride, methyltriethoxysilane and 4 - bromo - 2 - fluoro - 1 - trifluorovinyloxybenzene are used as raw materials to prepare a stain - resistant coating. Adding the nano - enhancer and the stain - resistant coating to the melamine decorative panel can effectively improve the strength and stain - resistant performance of the panel.

[0029] 2. The nano-reinforcing agent prepared in the present invention is added to the melamine decorative panel, which can effectively improve the strength of the decorative panel. The cellulose nanocrystals added during the preparation process of the nano-reinforcing agent have high strength and high modulus, providing an excellent mechanical basis for the nano-reinforcing agent. The nano-scale size of the reinforcing agent brings a high specific surface area, enabling the cellulose nanocrystals to form good dispersibility and interfacial bonding force in the matrix, contributing to improving the overall performance of the composite material. Moreover, the hydroxyl groups on its surface can achieve diversification of the reinforcing function through chemical modification, thereby enhancing the compatibility and bonding force of the material. The prepared nanoparticles, as inorganic fillers, can fill the micro-pores in the melamine decorative panel, improving the density and overall strength of the panel. The whisker morphology of the nanoparticles helps to form a three-dimensional network structure in the decorative panel, enhancing its mechanical properties and impact resistance, and further making the melamine decorative panel have high strength.

[0030] 3. The stain-resistant coating prepared in the present invention is evenly coated on the surface of the melamine decorative panel, which can effectively improve its stain-resistant performance. The main chain of the stain-resistant coating contains alternating units of carbon-oxygen bonds, making it exhibit flexible rotation characteristics and at the same time having a low surface energy. The low surface energy makes it difficult for water and other polar pollutants to wet the coating surface, thus effectively preventing the attachment of pollutants. Moreover, the presence of fluoride ions endows the stain-resistant coating with excellent chemical resistance, enabling it to resist the erosion of various chemical substances, so that the panel can still maintain its performance in a harsh environment. Detailed implementation manners

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Example 1: This example discloses a preparation method of a nano-reinforcing agent, including the following steps:

[0033] Q1: Add 0.4 g of cellulose nanocrystals to a container containing 10 mL of dimethyl sulfoxide, then add 12 g of L-lactide, heat to 128 °C under a nitrogen atmosphere, add 0.12 g of stannous octoate, react for 24 h. After the reaction, add methanol for precipitation, centrifuge at 12000 rpm for 12 min, wash with methanol and chloroform, and dry in vacuum at 50 °C for 36 h to obtain a composite;

[0034] Q2: Mix 1.42 g of calcium chloride and 1.05 g of ammonia water, then add 11 mL of distilled water to obtain a mixed solution. Subsequently, mix 3 mL of the mixed solution, 62.5 mL of cetyltrimethylammonium bromide, 11 mL of n-butanol, and 20 mL of cyclohexane, and add 0.0142 g of sucrose during the mixing process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion at a flow rate of 300 mL / min, continuously stir and react, stop passing carbon dioxide when no more precipitation occurs, stand for aging for 12 h, wash with ethanol, centrifuge, and dry at 75 °C for 32 h to obtain nanoparticles; Add 4 g of the composite and 1.1 g of the nanoparticles to a container containing a mixed solution of 7 mL of chloroform and 5 mL of petroleum ether, stir and mix for 24 h, then stand, dry at 38 °C for 36 h, and ball mill to obtain a nano-enhancer.

[0035] This example discloses a preparation method of a stain-resistant coating, including the following steps:

[0036] S1: Add 4 g of perfluoropolyether carboxylic acid and 4 mL of fluorocarbon solvent to a container, then drop 0.2 mL of pyridine, heat and stir at 74 °C for 14 min, then drop 2.5 mL of thionyl chloride, continue stirring for 10 h. After the stirring is completed, perform vacuum distillation, add 0.25 g of pentaerythritol triacrylate, and heat and react at 55 °C for 24 h to obtain Compound 1;

[0037] S2: Add 4.4 g of magnesium powder, 37.28 g of methyltriethoxysilane, 0.11 g of iodine powder, and 225 mL of tetrahydrofuran to a container, introduce nitrogen, heat the oil bath to 70 °C, and then drop 42 g of 4-bromo-2-fluoro-1-trifluorovinyloxybenzene into the container through a constant pressure dropping funnel. After the dropping is completed, stir for 24 h, then cool, distill, extract with n-hexane, filter, distill and concentrate, and perform vacuum distillation to obtain Compound 2;

[0038] S3: Add 3 g of Compound 1 and 3.5 mL of fluorocarbon solvent to a container, then add 0.5 g of Compound 2, stir and react for 45 min, then continue to heat and react at 55 °C for 12 h, then cool to room temperature, wash, dissolve, and separate to obtain a stain-resistant coating.

[0039] This example discloses a preparation method of a high-strength stain-resistant melamine decorative panel, including the following steps:

[0040] Step 1: Add 5 g of melamine and 2 g of the nano-enhancer to 265 mL of distilled water, stir and mix for 3 h to obtain a mixed emulsion. Immerse the impregnated paper in the mixed emulsion, soak for 12 h, take it out to obtain a composite impregnated paper;

[0041] Step 2: Select hard fiberboard as the base material, place the composite impregnated paper flat on the surface of the base material, then place it on a press, and adopt a hot pressing method with a high temperature for a short period and a low temperature for a long period. Set the pressure to 2 MPa, the temperature to 180 °C, and the hot pressing time to 45 s per sheet. Cool to obtain a melamine decorative board;

[0042] Step 3: Spray a stain-resistant coating on the surface of the melamine decorative board and dry it at 55 °C for 24 h to obtain a high-strength stain-resistant melamine decorative board.

[0043] Example 2: This example discloses a preparation method of a nano-enhancer, including the following steps:

[0044] Q1: Add 0.3 g of cellulose nanocrystals to a container containing 8 mL of dimethyl sulfoxide, then add 9 g of L-lactide, heat to 128 °C under a nitrogen atmosphere, add 0.09 g of stannous octoate, react for 24 h. After the reaction, add methanol for precipitation, centrifuge at 12000 rpm for 12 min, wash with methanol and chloroform, and dry in vacuum at 50 °C for 36 h to obtain a composite;

[0045] Q2: Mix and stir 1.23 g of calcium chloride and 0.9 g of ammonia water, then add 10 mL of distilled water to obtain a mixed solution. Subsequently, mix and stir 2 mL of the mixed solution, 50 mL of cetyltrimethylammonium bromide, 8 mL of n-butanol, and 15 mL of cyclohexane. Add 0.0123 g of sucrose during the mixing and stirring process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion at a flow rate of 300 mL / min, continuously stir and react, stop passing carbon dioxide when no more precipitation occurs, let it stand and age for 12 h, wash with ethanol, centrifuge, and dry at 75 °C for 32 h to obtain nanoparticles; Add 3 g of the composite and 1 g of the nanoparticles to a container containing a mixed solution of 6 mL of chloroform and 4 mL of petroleum ether, stir and mix for 24 h, then let it stand, dry at 38 °C for 36 h, and ball mill to obtain a nano-enhancer.

[0046] This example discloses a preparation method of a stain-resistant coating, including the following steps:

[0047] S1: Add 3 g of perfluoropolyether carboxylic acid and 3 mL of fluorocarbon solvent to a container, then drop in 0.19 mL of pyridine. After heating and stirring at 74 °C for 14 min, drop in 2 mL of thionyl chloride and continue stirring for 10 h. After the stirring ends, perform vacuum distillation, add 0.2 g of pentaerythritol triacrylate, and heat and react at 55 °C for 24 h to obtain Compound 1;

[0048] S2: Add 4.2 g of magnesium powder, 37.11 g of methyltriethoxysilane, 0.1 g of iodine powder and 200 mL of tetrahydrofuran into a container, introduce nitrogen, heat up to 70 °C in an oil bath, then add 38 g of 4-bromo-2-fluoro-1-trifluorovinyloxybenzene dropwise into the container through a constant pressure dropping funnel. After the dropping is completed, stir for 24 h, then cool, distill, add n-hexane for extraction, filter, distill and concentrate, and distill under reduced pressure to obtain Compound 2;

[0049] S3: Add 2 g of Compound 1 and 3 mL of fluorocarbon solvent into a container, then add 0.4 g of Compound 2, stir and react for 45 min, then continue to heat and react at 55 °C for 12 h, then cool down to room temperature, wash, dissolve, and separate liquid to obtain a stain-resistant coating.

[0050] This example discloses a preparation method of a high-strength stain-resistant melamine decorative panel, including the following steps:

[0051] Step 1: Add 4 g of melamine and 1 g of nano-enhancer into 250 mL of distilled water, stir and mix for 3 h to obtain a mixed emulsion. Put the impregnated paper into the mixed emulsion, soak for 12 h, take out to obtain a composite impregnated paper;

[0052] Step 2: Select a hard fiberboard as the substrate, place the composite impregnated paper flat on the surface of the substrate, then place it on a press, and adopt a hot pressing method of high temperature short cycle and low temperature long cycle. Set the pressure to 2 MPa, the temperature to 180 °C, and the hot pressing time to 45 s per sheet, and cool to obtain a melamine decorative panel containing;

[0053] Step 3: Spray the stain-resistant coating on the surface of the melamine decorative panel, dry at 55 °C for 24 h to obtain a high-strength stain-resistant melamine decorative panel.

[0054] Example 3: This example discloses a preparation method of a nano-enhancer, including the following steps:

[0055] Q1: Add 0.5 g of cellulose nanocrystals into a container equipped with 12 mL of dimethyl sulfoxide, then add 15 g of L-lactide, heat to 128 °C under a nitrogen atmosphere, add 0.15 g of stannous octoate, react for 24 h. After the reaction is completed, add methanol for precipitation, centrifuge at 12000 rpm for 12 min, wash with methanol and chloroform, and dry in vacuum at 50 °C for 36 h to obtain a composite;

[0056] Q2: Mix 1.62 g of calcium chloride and 1.2 g of ammonia water, then add 12 mL of distilled water to obtain a mixed solution. Subsequently, mix 4 mL of the mixed solution, 75 mL of cetyltrimethylammonium bromide, 14 mL of n-butanol, and 25 mL of cyclohexane and stir. Add 0.0162 g of sucrose during the mixing and stirring process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion at a flow rate of 300 mL / min, continuously stir and react, stop passing carbon dioxide until no more precipitation occurs, let it stand and age for 12 h, wash with ethanol, centrifuge, and dry at 75 °C for 32 h to obtain nanoparticles; Add 5 g of the composite and 1.2 g of the nanoparticles to a container containing a mixed solution of 8 mL of chloroform and 6 mL of petroleum ether, stir and mix for 24 h, then let it stand and dry at 38 °C for 36 h, and ball mill to obtain a nano-enhancer.

[0057] This example discloses a preparation method of a stain-resistant coating, including the following steps:

[0058] S1: Add 5 g of perfluoropolyether carboxylic acid and 5 mL of fluorocarbon solvent to a container, then drop in 0.21 mL of pyridine, heat and stir at 74 °C for 14 min, then drop in 3 mL of thionyl chloride, continue to stir for 10 h. After the stirring ends, perform vacuum distillation, add 0.3 g of pentaerythritol triacrylate, and heat and react at 55 °C for 24 h to obtain Compound 1;

[0059] S2: Add 4.6 g of magnesium powder, 37.45 g of methyltriethoxysilane, 0.12 g of iodine powder, and 250 mL of tetrahydrofuran to a container, pass in nitrogen, heat the oil bath to 70 °C, then drop 45 g of 4-bromo-2-fluoro-1-trifluorovinyloxybenzene into the container through a constant pressure dropping funnel. After the dropping is completed, stir for 24 h, then cool, distill, add n-hexane for extraction, filter, distill and concentrate, and perform vacuum distillation to obtain Compound 2;

[0060] S3: Add 4 g of Compound 1 and 5 mL of fluorocarbon solvent to a container, then add 0.6 g of Compound 2, stir and react for 45 min, then continue to heat and react at 55 °C for 12 h, then cool to room temperature, wash, dissolve, and separate the liquid to obtain a stain-resistant coating.

[0061] This example discloses a preparation method of a high-strength stain-resistant melamine decorative panel, including the following steps:

[0062] Step 1: Add 6 g of melamine and 3 g of the nano-enhancer to 280 mL of distilled water, stir and mix for 3 h to obtain a mixed emulsion. Put the impregnated paper into the mixed emulsion, soak for 12 h, take it out to obtain a composite impregnated paper;

[0063] Step 2: Select a hard fiberboard as the base material, place the composite impregnated paper flat on the surface of the base material, then place it on a press, and use a hot pressing method with a high temperature for a short period and a low temperature for a long period. Set the pressure to 2 MPa, the temperature to 180 °C, and the hot pressing time to 45 s per sheet. Cool to obtain a melamine decorative board;

[0064] Step 3: Spray a stain-resistant coating on the surface of the melamine decorative board and dry it at 55 °C for 24 h to obtain a high-strength stain-resistant melamine decorative board.

[0065] Example 4: This example discloses a preparation method of a nano-enhancer, including the following steps:

[0066] Q1: Add 0.35 g of cellulose nanocrystals to a container containing 9 mL of dimethyl sulfoxide, then add 11 g of L-lactide, heat to 128 °C under a nitrogen atmosphere, add 0.11 g of stannous octoate, react for 24 h. After the reaction is completed, add methanol for precipitation, centrifuge at 12000 rpm for 12 min, wash with methanol and chloroform, and dry in vacuum at 50 °C for 36 h to obtain a composite;

[0067] Q2: Mix and stir 1.31 g of calcium chloride and 1.1 g of ammonia water, then add 10.5 mL of distilled water to obtain a mixed solution. Subsequently, mix and stir 2.5 mL of the mixed solution, 55 mL of cetyltrimethylammonium bromide, 9 mL of n-butanol, and 18 mL of cyclohexane. Add 0.0131 g of sucrose during the mixing and stirring process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion at a flow rate of 300 mL / min, continuously stir and react, stop passing carbon dioxide when no more precipitation occurs, let it stand and age for 12 h, wash with ethanol, centrifuge, and dry at 75 °C for 32 h to obtain nanoparticles; Add 3.5 g of the composite and 1.05 g of the nanoparticles to a container containing a mixed solution of 6.5 mL of chloroform and 4.5 mL of petroleum ether, stir and mix for 24 h, then let it stand and dry at 38 °C for 36 h, and ball mill to obtain a nano-enhancer.

[0068] This example discloses a preparation method of a stain-resistant coating, including the following steps:

[0069] S1: Add 3.5 g of perfluoropolyether carboxylic acid and 4.5 mL of fluorocarbon solvent to a container, then drop 0.195 mL of pyridine, stir and heat to 74 °C for 14 min, then drop 2.4 mL of thionyl chloride, continue to stir for 10 h. After the stirring is completed, perform vacuum distillation, add 0.22 g of pentaerythritol triacrylate, and heat and react at 55 °C for 24 h to obtain Compound 1;

[0070] S2: Add 4.3 g of magnesium powder, 37.23 g of methyltriethoxysilane, 0.115 g of iodine powder, and 210 mL of tetrahydrofuran into a container. Introduce nitrogen gas, heat the oil bath to 70 °C, and then add 39 g of 4-bromo-2-fluoro-1-trifluorovinyloxybenzene dropwise into the container through a constant-pressure dropping funnel. After the dropping is completed, stir for 24 h, then cool, distill, add n-hexane for extraction, filter, distill and concentrate, and perform vacuum distillation to obtain Compound 2;

[0071] S3: Add 2.5 g of Compound 1 and 4 mL of fluorocarbon solvent into a container, then add 0.45 g of Compound 2. After stirring and reacting for 45 min, continue to heat and react at 55 °C for 12 h, then cool to room temperature, wash, dissolve, and separate the liquid to obtain a stain-resistant coating.

[0072] This example discloses a preparation method of a high-strength stain-resistant melamine decorative panel, including the following steps:

[0073] Step 1: Add 4.5 g of melamine and 1.5 g of nano-enhancer into 260 mL of distilled water, stir and mix for 3 h to obtain a mixed emulsion. Immerse the impregnated paper into the mixed emulsion, soak for 12 h, take it out to obtain a composite impregnated paper;

[0074] Step 2: Select a hard fiberboard as the substrate, place the composite impregnated paper flat on the surface of the substrate, then place it on a press, and adopt a hot pressing method of high temperature and short cycle, low temperature and long cycle. Set the pressure to 2 MPa, the temperature to 180 °C, and the hot pressing time to 45 s per sheet, and then cool to obtain a melamine decorative panel containing;

[0075] Step 3: Spray a stain-resistant coating on the surface of the melamine decorative panel, and dry at 55 °C for 24 h to obtain a high-strength stain-resistant melamine decorative panel.

[0076] Example 5: This example discloses a preparation method of a nano-enhancer, including the following steps:

[0077] Q1: Add 0.45 g of cellulose nanocrystals into a container equipped with 11 mL of dimethyl sulfoxide, then add 14 g of L-lactide, heat to 128 °C under a nitrogen atmosphere, add 0.14 g of stannous octoate, react for 24 h. After the reaction is completed, add methanol for precipitation, centrifuge at 12000 rpm for 12 min, wash with methanol and chloroform, and vacuum dry at 50 °C for 36 h to obtain a composite;

[0078] Q2: Mix 1.58 g of calcium chloride and 0.98 g of ammonia water, then add 11.5 mL of distilled water to obtain a mixed solution. Subsequently, mix 3.5 mL of the mixed solution, 70 mL of cetyltrimethylammonium bromide, 12 mL of n-butanol, and 23 mL of cyclohexane, and add 0.0158 g of sucrose during the mixing process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion at a flow rate of 300 mL / min, continuously stir and react, stop passing carbon dioxide until no more precipitation occurs, let it stand for aging for 12 h, wash with ethanol, centrifuge, and dry at 75 °C for 32 h to obtain nanoparticles; add 4.5 g of the composite and 1.15 g of the nanoparticles to a container containing a mixed solution of 7.5 mL of chloroform and 5.5 mL of petroleum ether, stir and mix for 24 h, then let it stand and dry at 38 °C for 36 h, and ball mill to obtain a nano-enhancer.

[0079] This example discloses a preparation method of a stain-resistant coating, including the following steps:

[0080] S1: Add 4.5 g of perfluoropolyether carboxylic acid and 3.5 mL of fluorocarbon solvent to a container, then drop 0.205 mL of pyridine. After heating and stirring at 74 °C for 14 min, drop 2.8 mL of thionyl chloride, continue stirring for 10 h. After the stirring ends, perform vacuum distillation, add 0.28 g of pentaerythritol triacrylate, and react by heating at 55 °C for 24 h to obtain Compound 1;

[0081] S2: Add 4.5 g of magnesium powder, 37.38 g of methyltriethoxysilane, 0.118 g of iodine powder, and 240 mL of tetrahydrofuran to a container, introduce nitrogen, heat the oil bath to 70 °C, and then drop 43 g of 4-bromo-2-fluoro-1-trifluorovinyloxybenzene into the container through a constant pressure dropping funnel. After the dropping is completed, stir for 24 h, then cool, distill, extract with n-hexane, filter, distill and concentrate, and perform vacuum distillation to obtain Compound 2;

[0082] S3: Add 3.5 g of Compound 1 and 4.5 mL of fluorocarbon solvent to a container, then add 0.55 g of Compound 2, stir and react for 45 min, then continue to react by heating at 55 °C for 12 h, then cool to room temperature, wash, dissolve, and separate the liquid to obtain a stain-resistant coating.

[0083] This example discloses a preparation method of a high-strength stain-resistant melamine decorative panel, including the following steps:

[0084] Step 1: Add 5.5 g of melamine and 2.5 g of the nano-enhancer to 270 mL of distilled water, stir and mix for 3 h to obtain a mixed emulsion. Put the impregnated paper into the mixed emulsion, soak for 12 h, and take it out to obtain a composite impregnated paper;

[0085] Step 2: Select hard fiberboard as the base material, lay the composite impregnated paper flat on the surface of the base material, then place it on a press, and adopt a hot pressing method with a high temperature for a short period and a low temperature for a long period. Set the pressure to 2 MPa, the temperature to 180 °C, and the hot pressing time to 45 s per sheet. Cool to obtain a melamine decorative board.

[0086] Step 3: Spray a stain-resistant coating on the surface of the melamine decorative board and dry it at 55 °C for 24 h to obtain a high-strength and stain-resistant melamine decorative board.

[0087] Comparative Example 1: Compared with Example 1, in the process of preparing the nano-enhancer in Comparative Example 1, L-lactide is not added, and other conditions remain unchanged.

[0088] Comparative Example 2: Compared with Example 1, in the process of preparing the stain-resistant coating in Comparative Example 2, perfluoropolyether carboxylic acid is not added, and other conditions remain unchanged.

[0089] Comparative Example 3: Compared with Example 1, in the process of preparing the high-strength and stain-resistant melamine decorative board in Comparative Example 3, the nano-enhancer is not added, and other conditions remain unchanged.

[0090] Comparative Example 4: Compared with Example 1, in the process of preparing the high-strength and stain-resistant melamine decorative board in Comparative Example 4, the stain-resistant coating is not added, and other conditions remain unchanged.

[0091] Experimental Example: Perform performance tests on the high-strength and stain-resistant melamine decorative boards prepared in Examples 1-5 and Comparative Examples 1-4. Test the strength and stain resistance of the samples according to GB / T 17657-2013. The test results are shown in Table 1:

[0092] Table 1

[0093]

[0094]

[0095] According to the stain resistance test, when the material grade is 5, it indicates that there is no obvious change on the material surface; when the material grade is 4, there are slight changes in the surface gloss and / or color of the material; when the material grade is 3, there are moderate changes in the surface gloss and / or color of the material; when the material grade is 2, there are obvious changes in the surface gloss and / or color of the material; when the material grade is 1, there are deformations and / or bubbles on the material surface. It can be seen from the test results in Table 1 that the melamine decorative panels prepared in Examples 1-5 of the present invention have excellent strength and stain resistance. By comparing Comparative Example 1 with Examples 1-5, it can be seen that adding L-lactide can effectively improve the strength of the melamine decorative panel; by comparing Comparative Example 2 with Examples 1-5, it can be seen that adding perfluoropolyether carboxylic acid can effectively improve the stain resistance of the melamine decorative panel; by comparing Comparative Example 3 with Examples 1-5, it can be seen that adding nano-enhancers can effectively improve the strength of the melamine decorative panel; by comparing Comparative Example 4 with Examples 1-5, it can be seen that adding stain-resistant coatings can effectively improve the stain resistance of the melamine decorative panel.

[0096] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

[0097] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to only the specific embodiments. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art in the technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing a high-strength stain-resistant melamine decorative panel, characterized in that, It includes the following steps: Step 1: Add melamine and nano-enhancer into distilled water, stir and mix evenly to obtain a mixed emulsion. Put the impregnated paper into the mixed emulsion, soak it, and then take it out to obtain a composite impregnated paper; Step 2: Select a hard fiberboard as the substrate, place the composite impregnated paper flat on the surface of the substrate, then place it on a press, perform hot pressing and cooling to obtain a melamine decorative board; Step 3: Spray a stain-resistant coating on the surface of the melamine decorative board and dry it to obtain a high-strength stain-resistant melamine decorative board.

2. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 1, characterized in that, In the said Step 1, the dosage ratio of melamine, nano-enhancer and distilled water is (4-6) g : (1-3) g : (250-280) mL, the stirring and mixing time is 2-3 h, and the soaking time is 8-12 h; in the said Step 2, a hot pressing method with high temperature and short cycle and low temperature and long cycle is adopted, the set pressure is 2-3 MPa, the temperature is 160-200 °C, and the hot pressing time is 30-60 s for each sheet; in the said Step 3, the drying temperature is 45-55 °C and the time is 18-24 h.

3. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 1, characterized in that, The preparation method of the said nano-enhancer includes the following steps: Q1: Add cellulose nanocrystals into a container filled with dimethyl sulfoxide, then add L-lactide, heat it under a nitrogen atmosphere, then add stannous octoate, react, after the reaction ends, precipitate, centrifuge, wash, and vacuum dry to obtain a composite; Q2: Mix and stir calcium chloride and ammonia water, then add distilled water to obtain a mixed solution. Subsequently, mix and stir the mixed solution, cetyltrimethylammonium bromide, n-butanol and cyclohexane, add sucrose during the mixing and stirring process to obtain a mixed emulsion. Pass carbon dioxide into the mixed emulsion, continuously stir and react, stop passing carbon dioxide when no more precipitation occurs, let it stand for aging, wash, centrifuge, and dry to obtain nanoparticles; Add the composite and nanoparticles into a container filled with a mixed solution of chloroform and petroleum ether, stir and mix, then let it stand and dry, and ball mill to obtain a nano-enhancer.

4. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 3, characterized in that, In the said Q1, the dosage ratio of cellulose nanocrystals, dimethyl sulfoxide, L-lactide and stannous octoate is (0.3-0.5) g : (8-12) mL : (9-15) g : (0.09-0.15) g. Add stannous octoate when the system temperature is 128-135 °C, the reaction time is 18-24 h, add methanol for precipitation, the centrifugation speed is 8000-12000 rpm, the time is 8-12 min, wash with methanol and chloroform, and the vacuum drying temperature is 40-50 °C and the time is 24-36 h.

5. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 3, characterized in that, In Q2, the dosage ratio of calcium chloride, ammonia water and distilled water is (1.23 - 1.62) g : (0.9 - 1.2) g : (10 - 12) mL, the volume ratio of the mixed solution, cetyltrimethylammonium bromide, n-butanol and cyclohexane is (2 - 4) : (50 - 75) : (8 - 14) : (15 - 25), the flow rate of carbon dioxide introduced is 300 mL / min, the static aging time is 12 - 15 h, it is washed with ethanol, the drying temperature is 70 - 80 °C, and the time is 24 - 32 h; the dosage ratio of the complex, nanoparticles, chloroform and petroleum ether is (3 - 5) g : (1 - 1.2) g : (6 - 8) mL : (4 - 6) mL, the mixing and stirring time is 20 - 24 h, the drying temperature is 35 - 38 °C, and the time is 32 - 36 h.

6. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 1, characterized in that, The preparation method of the stain-resistant coating includes the following steps: S1: Add perfluoropolyether carboxylic acid and fluorocarbon solvent into a container, then drop in pyridine, after heating and stirring, drop in thionyl chloride, continue stirring, after the stirring ends, perform reduced pressure distillation, add pentaerythritol triacrylate, and heat for reaction to obtain Compound 1; S2: Add magnesium powder, methyltriethoxysilane, iodine powder and tetrahydrofuran into a container, introduce nitrogen, raise the temperature by oil bath, then drop 4-bromo-2-fluoro-1-trifluorovinyloxybenzene into the container through a constant pressure dropping funnel, after the dropping is completed, stir, then cool, distill, add n-hexane for extraction, filter, distill and concentrate, and perform reduced pressure distillation to obtain Compound 2; S3: Add Compound 1 and fluorocarbon solvent into a container, then add Compound 2, after stirring and reacting, continue to raise the temperature for reaction, then cool to room temperature, wash, dissolve, and separate the liquid to obtain the stain-resistant coating.

7. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 6, characterized in that, In S1, the dosage ratio of perfluoropolyether carboxylic acid, fluorocarbon solvent, pyridine, thionyl chloride and pentaerythritol triacrylate is (3 - 5) g : (3 - 5) mL : (0.19 - 0.21) mL : (2 - 3) mL : (0.2 - 0.3) g, the heating and stirring temperature is 70 - 74 °C, the stirring time is 10 - 14 min, the continuous stirring time is 6 - 10 h, the heating reaction temperature is 45 - 55 °C, and the time is 24 - 28 h.

8. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 6, wherein, In S2, the dosage ratio of magnesium powder, methyltriethoxysilane, iodine powder, tetrahydrofuran and 4-bromo-2-fluoro-1-trifluorovinyloxybenzene is (4.2 - 4.6) g : (37.11 - 37.45) g : (0.1 - 0.12) g : (200 - 250) mL : (38 - 45) g, the oil bath temperature rise is 60 - 70 °C, and the stirring time is 20 - 24 h.

9. The preparation method of the high-strength and stain-resistant melamine decorative panel according to claim 6, characterized in that, In S3, the dosage ratio of Compound 1, fluorocarbon solvent and Compound 2 is (2 - 4) g : (2 - 5) mL : (0.4 - 0.6) g, the stirring reaction time is 30 - 45 min, the temperature rise reaction temperature is 50 - 60 °C, and the reaction time is 10 - 12 h.

10. Melamine decorative panel with high strength and stain resistance, characterized in that, Prepared by the method according to any one of claims 1 - 9.

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