A multi-layered board and a method of manufacturing the same

Abstract

The application discloses a kind of multilayer board and its preparation method, the preparation method includes: (1) by first adhesive hot-pressing adhesion fixed on the upper surface of core material layer Flame-retardant board;(2) the lower surface of core material layer is sprayed moisture-proof paint.The multilayer board provided in the application, the upper surface is flame-retardant board, and the flame-retardant performance is good;The lower surface is coated with moisture-proof paint, can resist the influence of potential humid environment such as ground, wall to wood, can greatly prolong the service life of board material.Meanwhile, the adhesive used in the application is isocyanate adhesive, and the formaldehyde emission is low, which is environmentally friendly;The preparation process of the board involves mainly pressing, and the process is simple and easy to produce.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plate preparation, and particularly relates to a multi-layer plate and a preparation method thereof. BACKGROUND

[0002] Wooden plates are widely used in life, and with the differentiated requirements for their performance, multi-layer wooden plates with different structures have been developed and put into the market. Generally speaking, the performance such as mildew resistance, antibiosis, flame retardation, moisture resistance and the like is the focus of attention of the multi-layer plate performance. Among them, due to the flammability of the wood plate, the fireproof problem has been an urgent problem to be solved in the field of building decoration and building engineering, and the flame retardation performance of the wood has also been greatly concerned. And due to the fact that the application occasion of the multi-layer plate may exist in a dark and humid environment, how to improve the moisture resistance of the plate also becomes very important.

[0003] In the prior art, for the flame retardation performance of the multi-layer wood, there are halogen-containing flame retardants, which will release a large amount of toxic and harmful gas in the flame retardation process, and the safety hidden danger is high. There are also composite substances for improving the flame retardation performance of the plate, such as the fireproof layer raw materials used in the multi-layer plate provided in the patent document CN109421339A: 20 parts of plant fiber, 15 parts of polystyrene, 10 parts of polypropylene, 4 parts of adhesive, 2 parts of plasticizer, 2 parts of flame retardant, 3 parts of liquid paraffin, 1 part of melamine, 5 parts of kaolin, 4 parts of glass fiber, 5 parts of limestone powder, 2 parts of expanded perlite and 1 part of toluene diisocyanate; the components are complex, and a large amount of high molecular substances are contained, which are extremely easy to emit harmful substances when burning. For the moisture resistance, there are not too many special moisture resistance studies for wood at present, such as the moisture resistance varnish in the patent document CN108948894A, which is made of the following raw materials in parts by weight: perchloroethylene resin 20-25 parts, epoxy chloropropane 0.5-1 part, butyl acetate 15-20 parts, acetone 15-20 parts, toluene 35-50 parts;

[0004] The patent document CN109233393A provides a moisture-proof and corrosion-resistant coating made of the following raw materials in parts by weight: adipate 20-30 parts, water-based fluorocarbon emulsion 15-25 parts, methyl acrylate trifluoroethyl ester 4-7 parts, modified nano zinc oxide 1-3 parts, formaldehyde adsorbent 1-2 parts, ant termite aid 1.2-2.5 parts, antimony-doped tin oxide nanocrystal 3-5 parts, glass fiber 3-6 parts, basalt fiber 3-6 parts, nano diatomite 6-10 parts, talc powder 6-8 parts, plant glue 2-5 parts, moisture resistance agent 1-3 parts, coupling agent 2-6 parts, lubricant 2-4 parts, dispersant 2-4 parts, defoamer 1-3 parts;

[0005] The moisture-proof paint in the patent document CN104893487A contains the following components in mass parts: 4-chloro-3,5-dimethylphenol 13-25 parts, 1,4-dichlorobenzene 3-10 parts, polysulfide rubber 7-16 parts, lead trioxide 4-10 parts, barite powder 3-12 parts, rosin modified phenolic resin 12-22 parts, butyl acetate 2-6 parts, rosin 3.5-8.5 parts, triethanolamine 1.2-3 parts, dibutyltin dilaurate 0.05-0.16 parts, stearate 0.08-0.23 parts, propyl p-hydroxybenzoate 0.04-0.1 parts, sorbitol 2-5 parts, cyclohexanone 1-4 parts, ammonium polyphosphate 2-8 parts, yellow dextrin 0.9-2.2 parts, silicone emulsion 0.3-0.9 parts.

[0006] It can be seen that the moisture-proof paint for wood-based articles provided in the prior art uses a variety of substances and contains many organic substances, and the components are complex.

[0007] Therefore, it is still necessary to provide a multi-layer board with good flame-retardant performance and moisture-proof performance. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a multi-layer board and a preparation method thereof, which has good flame-retardant and moisture-proof performance, and a simple preparation process and is easy to make.

[0009] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0010] A preparation method of a multi-layer board, comprising the following steps:

[0011] (1) fixing the flame-retardant board on the upper surface of the core layer by hot pressing and bonding with the first adhesive;

[0012] (2) spraying the moisture-proof paint on the lower surface of the core layer;

[0013] The preparation of the flame-retardant board comprises the following steps:

[0014] S1, preparing a composite flame-retardant powder: calcining vermiculite at 350-420 DEG C for 1-4 h, then grinding and sieving to 80-120 meshes; then adding to an acetic acid solution for treatment for 8-16 h, and then performing filtration, washing and drying treatment to obtain material a; then, according to a mass ratio of 1:0.5-2, mixing material a with hydrotalcite, then adding to water, stirring, then adding a mixed solution of sodium dodecylbenzenesulfonate and KH550, then stirring at 75-85 DEG C for 0.5-2 h; after stirring, performing filtration, washing and drying treatment to obtain the composite flame-retardant powder;

[0015] S2, preparing modified composite fiber: pulverize the rice straw to 1.5-3.5 cm, then perform steam explosion, pressure maintaining time 3-8 min, explosion pressure 1.2-1.4 MPa; after unloading, naturally air dry to obtain straw material; mix the bamboo fiber and the straw material according to a mass ratio of 1:1.5-2.5, then grind and sieve to 50-100 meshes to obtain the modified composite fiber, for standby use;

[0016] S3, preparing a slurry: taking 100-200 parts of magnesium chloride, 15-30 parts of composite flame-retardant powder and 5-12 parts of modified composite fiber by weight, then sequentially adding to 150-300 parts of water, stirring uniformly to obtain a slurry;

[0017] S4, adding the slurry obtained in step S3 into a mold, cold pressing to obtain the flame-retardant plate.

[0018] Preferably, the preparation of the multi-layer plate further comprises: hot pressing and bonding the panel layer to the outer surface of the flame-retardant plate by a second adhesive;

[0019] The core layer is obtained by hot pressing not less than 3 layers of equal-thickness solid wood plates by a third adhesive. It needs to be particularly emphasized that the lower surface of the core layer can also be hot pressed with a corresponding panel layer of other functions, and then sprayed with moisture-proof paint to meet different use requirements, based on the consideration of aesthetics and other factors.

[0020] Preferably, the thickness of the panel layer is 1-6 mm, the thickness of the flame-retardant plate is 1-2.5 mm, the thickness of the core layer is 8-15 mm, and the thickness of the moisture-proof paint is 0.1-0.2 mm.

[0021] Preferably, the glue coating amount of the first adhesive, the second adhesive and the third adhesive is 80-150 g / m 2 ;

[0022] The first adhesive, the second adhesive and the third adhesive have the same components. Obviously, the above-mentioned adhesives can be selected from common soybean protein biomass formaldehyde-free adhesives, urea-formaldehyde resin adhesives, isocyanate adhesives and the like; preferably, an isocyanate adhesive is selected; more preferably, the first adhesive, the second adhesive and the third adhesive are obtained by mixing 6.5 parts of isocyanate adhesive and 0.8 parts of EVA emulsion by weight.

[0023] Preferably, the hot pressing pressure for hot pressing and bonding the flame-retardant plate to the upper surface of the core layer is 9-13 MPa, the hot pressing temperature is 175-185℃, and the hot pressing time is 4-10 min;

[0024] The hot pressing pressure for hot pressing and bonding the panel layer to the outer surface of the flame-retardant plate is 8-12 MPa, the hot pressing temperature is 175-185℃, and the hot pressing time is 5-10 min;

[0025] The hot-pressing pressure of the solid wood board pressed by the third adhesive is 10-15 MPa, the hot-pressing temperature is 175-185 DEG C, and the hot-pressing time is 5-15 min.

[0026] Preferably, in step S1, the concentration of the acetic acid solution is 1-1.5 mol / L, the dosage ratio of the vermiculite to the acetic acid solution is 1g:30-50 mL; the mass ratio of the sodium dodecyl benzene sulfonate to the KH550 is 1:1, the concentration of the sodium dodecyl benzene sulfonate is 1.5-3.5 wt%; the dosage ratio of the sodium dodecyl benzene sulfonate to the hydrotalcite is 0.06-0.12:1.

[0027] In step S4, the cold-pressing pressure is 6-12 MPa, the cold-pressing temperature is 23-25 DEG C, and the cold-pressing time is 6-15 min.

[0028] Preferably, the preparation of the moisture-proof paint comprises the following steps:

[0029] The chitosan is added into the sodium hydroxide solution and completely dissolved at 95-105 DEG C; then the PMMA is added, after uniform stirring, the ammonium persulfate and sorbitol are added, and the reaction solution is obtained by stirring and reacting at 45-55 DEG C for 1-4 h; the modified rectorite is added into the reaction solution, and the KH550 is added, and the moisture-proof paint is obtained by stirring at 25-35 DEG C for 0.5-2 h.

[0030] Preferably, the concentration of the sodium hydroxide solution is 45-55 wt%, the dosage ratio of the chitosan to the sodium hydroxide solution is 1g:12-18 mL; the mass ratio of the chitosan, the PMMA, the ammonium persulfate, the sorbitol, the modified rectorite and the KH550 is 1:10-40:0.02-0.06:0.004-0.01:0.5-0.8:0.08-0.15.

[0031] Preferably, the preparation of the modified rectorite comprises the following steps: the rectorite is added into a 7-12 wt% hydrochloric acid solution, stirred at 65-85 DEG C for 0.5-4 h, and then filtered, washed and dried, and the modified rectorite is obtained.

[0032] In addition, the present application also protects the multi-layer board prepared by the above method.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] (1) The multi-layer board provided by the present application has a good flame-retardant property and can resist external combustion risks; the lower surface is coated with moisture-proof paint, which can resist the influence of potential moisture environment on the wood, and can greatly prolong the service life of the board.

[0035] (2) In the present application, the fire-retardant board uses composite fire-retardant powder, modified composite fiber and magnesium chloride as raw materials, wherein the composite fire-retardant powder strengthens the fire-retardant performance of the fire-retardant board, the modified composite fiber strengthens the mechanical properties of the fire-retardant board, and the magnesium chloride is a gel material. The raw materials are common and low in cost. Specifically:

[0036] Both vermiculite and hydrotalcite have good fire-retardant performance, but direct use of the two has the disadvantages of poor dispersibility and poor usability. In the present application, the vermiculite is first calcined and acidized to enhance the surface roughness of the vermiculite, improve its dispersibility, adjust the interlayer spacing of the vermiculite, and further strengthen its expandability, thereby achieving the purpose of strengthening fire retardation. Then the vermiculite powder is mixed with hydrotalcite and modified using a composite modifier (a mixed system of sodium dodecyl benzene sulfonate and KH550) to improve its dispersibility. It should be particularly emphasized that the fire-retardant mechanism of hydrotalcite mainly lies in its ability to absorb smoke, reduce temperature, and prevent further combustion. The fire-retardant mechanism of vermiculite mainly lies in its heat conduction effect, heat absorption effect, air isolation effect, and combustible dilution effect. In the present application, the two are compounded and treated with a specific composite modifier to maximize the synergistic effect of fire retardation.

[0037] The modified fiber uses bamboo fiber and rice straw as the main raw materials, and the use of the two can ensure the mechanical properties of the fire-retardant board. Rice straw is a crop waste, and its use has both ecological and economic values. The price of rice straw is more advantageous than that of bamboo fiber, and from the point of view of flammability, bamboo fiber burns faster. Therefore, considering comprehensively, the amount of straw fiber used in the present application is larger than that of bamboo fiber. Before use, the straw is first subjected to steam explosion to remove hemicellulose and lignin, thereby improving the strength of the straw and further improving the mechanical properties of the fire-retardant board.

[0038] The fire-retardant board has simple components and is relatively easy to prepare.

[0039] (3)The moisture-proof paint in the application takes chitosan, PMMA and attapulgite as main raw materials; chitosan and PMMA occur polymerization under the initiation of ammonium persulfate, and sorbitol plays the role of solubilization; the addition of attapulgite to the obtained polymer can greatly improve the corrosion resistance and wear resistance of the paint, and the paint also has certain flame retardant performance; in order to improve the dispersibility of attapulgite in the system, the attapulgite is acid-modified before use, and hydroxyl groups and amino groups are introduced; after the treatment, the hydroxyl groups and amino groups contained in chitosan and the amino groups contained in KH550 can interact to form a large network structure, improve the compactness of film formation, and further improve the moisture-proof and waterproof effects; and the hydroxyl groups and other groups contained in the solid wood board can interact with the amino groups to ensure the tightness of film formation. In short, the moisture-proof paint obtained by the application can cover the wood pores by the material system formed by chitosan and PMMA, and the addition of attapulgite can further strengthen the filling of the pores and further improve the moisture resistance of the wood. The moisture-proof paint has simple components, is relatively easy to prepare, and is environmentally friendly.

[0040] (4)The adhesive used in the application is an isocyanate adhesive with low formaldehyde emission and environmental protection; the preparation process of the board mainly involves pressing, and the process is simple and easy to manufacture. DETAILED DESCRIPTION

[0041] The embodiments of the application will be described in detail below, all of which are exemplary and intended to explain the application, and cannot be understood as limiting the application.

[0042] In the embodiments of the application, the panel layer is black sandalwood solid wood veneer; and the solid wood board is poplar veneer.

[0043] The vermiculite is purchased from Hebei Yanzixi Mine Product Processing Factory; the chitosan is purchased from Hubei Jianyuan Chemical Co., Ltd., and the degree of deacetylation is 90%; the hydrotalcite is purchased from Shaoyang Tiantang Auxiliary Chemical Co., Ltd., and the average particle size is about 0.6 μm; the bamboo fiber is purchased from Jiangyin Bailu Textile Trade Co., Ltd.; the isocyanate adhesive is purchased from Shanghai Huntsman Polyurethane Co., Ltd.; the EVA emulsion is purchased from Yunnan Zhengbang Technology Co., Ltd.; and the PMMA is SR6500 purchased from Shanghai Furun Plastic Technology Co., Ltd.

[0044] In the application, the rest of the unexplained places are the conventional means mastered by those skilled in the art (such as spraying / coating of the moisture-proof paint); and the materials without the source are commercially available.

[0045] Example 1

[0046] A preparation method of a multi-layer board, comprising the following steps:

[0047] (1)The 2 mm thick flame-retardant board is coated with a first adhesive (the glue coating amount is 120 g / m2 ) hot-pressing (hot-pressing pressure 12 MPa, hot-pressing temperature 180℃, hot-pressing time 8 min) is adhered and fixed on the upper surface of the core material layer; wherein the core material layer is prepared by 4 layers of 3mm equal-thickness solid wood boards through the third adhesive (the glue coating amount is 110g / m 2 ) hot-pressing;

[0048] (2) spraying 0.15mm moisture-proof paint on the lower surface of the core material layer;

[0049] The first adhesive and the third adhesive are the same, and are prepared by mixing 65g of isocyanate adhesive and 8g of EVA emulsion.

[0050] The preparation of the fire-retardant board comprises the following steps:

[0051] S1, preparing a composite fire-retardant powder: calcining vermiculite at 390℃ for 2h, then grinding and sieving to 100 meshes; then adding to 1.2mol / L acetic acid solution for 12h, then filtering, washing and drying to obtain material a; then, according to the mass ratio of 1:1.2, mixing material a with hydrotalcite, then adding to water, then adding a mixed solution of 2.5wt% sodium dodecyl benzene sulfonate and 2.5wt% KH550 after stirring, then stirring at 80℃ for 1h; after stirring, filtering, washing and drying, the composite fire-retardant powder is obtained; wherein the amount ratio of vermiculite to acetic acid solution is 1g:40mL, and the amount ratio of sodium dodecyl benzene sulfonate to hydrotalcite is 0.08:1;

[0052] S2, preparing a modified composite fiber: crushing water rice straw to 3cm, then performing steam explosion, pressure maintaining time 6min, explosion pressure 1.3MPa; after discharging, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to the mass ratio of 1:2, then grinding and sieving to 80 meshes to obtain the modified composite fiber, which is ready for use;

[0053] S3, preparing a liquid: taking 150g of magnesium chloride, 25g of the composite fire-retardant powder and 6g of the modified composite fiber by weight, then adding to 200g of water in sequence, then stirring uniformly to obtain the liquid;

[0054] S4, adding the liquid obtained in step S3 to a mold, then cold-pressing (9MPa, 25℃, 8min) to obtain the fire-retardant board.

[0055] The preparation of the moisture-proof paint comprises the following steps:

[0056] Chitosan is added to a 50wt% sodium hydroxide solution and completely dissolved at 100℃; then PMMA is added, after stirring uniformly, ammonium persulfate and sorbitol are added, and stirring reaction is carried out at 50℃ for 3h to obtain a reactant solution; the modified rectorite is added to the reactant solution, and then KH550 is added, and stirring is carried out at 30℃ for 1h to obtain the moisture-proof coating; wherein the amount ratio of chitosan to sodium hydroxide solution is 1g:15mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:20:0.03:0.006:0.6:0.1.

[0057] Preparation of the modified rectorite includes the following steps: rectorite is added to a 9wt% hydrochloric acid solution, stirring is carried out at 75℃ for 2h, and then filtration, washing and drying treatment are carried out to obtain the modified rectorite.

[0058] Example 2

[0059] A preparation method of a multi-layer board includes the following steps:

[0060] (1) a 2mm-thick flame-retardant board is fixed on the upper surface of a core layer by hot pressing (hot pressing pressure 12MPa, hot pressing temperature 180℃, hot pressing time 8min) with a first adhesive (glue coating amount 120g / m 2 ); wherein the core layer is obtained by hot pressing of four 3mm-thick solid wood boards with a third adhesive (glue coating amount 110g / m 2 );

[0061] (2) 0.15mm moisture-proof coating is sprayed on the lower surface of the core layer.

[0062] Wherein, the first adhesive and the third adhesive are the same, and are obtained by mixing 65g of isocyanate adhesive and 8g of EVA emulsion.

[0063] Preparation of the flame-retardant board includes the following steps:

[0064] S1, preparation of a composite flame-retardant powder: vermiculite is calcined at 400℃ for 1.5h, and then ground and sieved to 100 meshes; then it is added to a 1.3mol / L acetic acid solution for treatment for 16h, and then filtration, washing and drying treatment are carried out to obtain material a; then, according to a mass ratio of 1:1.3, material a and hydrotalcite are mixed, and then added to water, and after stirring, a mixed solution of 2.4wt% dodecylbenzenesulfonic acid sodium and 2.4wt% KH550 is added, and then stirring reaction is carried out at 85℃ for 1.5h; after stirring is completed, filtration, washing and drying treatment are carried out to obtain the composite flame-retardant powder; wherein the amount ratio of vermiculite to acetic acid solution is 1g:45mL, and the amount ratio of dodecylbenzenesulfonic acid sodium to hydrotalcite is 0.09:1.

[0065] S2, preparing modified composite fiber: pulverizing rice straw to 3 cm, then performing steam explosion, pressure maintaining time 6 min, explosion pressure 1.3 MPa; after unloading, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to a mass ratio of 1:2.1, then grinding and sieving 80 meshes to obtain modified composite fiber, for standby use;

[0066] S3, preparing a liquid: respectively taking 150 g of magnesium chloride, 27 g of composite flame-retardant powder and 6.5 g of modified composite fiber by weight, then sequentially adding into 200 g of water, stirring uniformly to obtain a liquid;

[0067] S4, adding the liquid obtained in step S3 into a mold, cold pressing (9 MPa, 25℃, 8 min) to obtain a flame-retardant plate.

[0068] Preparation of the moisture-proof coating includes the following steps:

[0069] Adding chitosan into a 55wt% sodium hydroxide solution, completely dissolving at 100℃; then adding PMMA, stirring uniformly, then adding ammonium persulfate and sorbitol, stirring and reacting at 55℃ for 2h to obtain a reactant solution; adding modified rectorite into the reactant solution, then adding KH550, stirring at 30℃ for 1h to obtain the moisture-proof coating; wherein the usage ratio of chitosan to sodium hydroxide solution is 1g:17mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:25:0.04:0.007:0.65:0.09.

[0070] Preparation of the modified rectorite includes the following steps: adding rectorite into a 9wt% hydrochloric acid solution, stirring at 75℃ for 2h, then filtering, washing and drying to obtain the modified rectorite.

[0071] Example 3

[0072] A method for preparing a multi-layer plate includes the following steps:

[0073] (1) hot pressing (hot pressing pressure 12 MPa, hot pressing temperature 180℃, hot pressing time 8 min) a 2mm-thick flame-retardant plate to the upper surface of a core layer by a first adhesive (glue coating amount 120g / m 2 ); wherein the core layer is obtained by hot pressing four 3mm-thick solid wood plates by a third adhesive (glue coating amount 110g / m 2 );

[0074] (2) spraying 0.15mm moisture-proof coating on the lower surface of the core layer;

[0075] The first adhesive and the third adhesive component are the same, and are obtained by mixing 65 g of isocyanate adhesive and 8 g of EVA emulsion by weight.

[0076] The preparation of the fire-retardant board comprises the following steps:

[0077] S1, preparing a composite fire-retardant powder: calcining vermiculite at 395℃ for 3h, then grinding and sieving to 100 meshes; then adding to 1.1 mol / L acetic acid solution for 16h, then filtering, washing and drying to obtain material a; then, according to the mass ratio of 1:1.2, mixing material a with hydrotalcite, then adding to water, then adding a mixed solution of 2.6wt% sodium dodecyl benzene sulfonate and 2.6wt% KH550 after stirring, then stirring and reacting at 80℃ for 1h; after stirring, filtering, washing and drying, the composite fire-retardant powder is obtained; wherein the amount ratio of vermiculite to acetic acid solution is 1g:40mL, and the amount ratio of sodium dodecyl benzene sulfonate to hydrotalcite is 0.07:1;

[0078] S2, preparing a modified composite fiber: crushing water rice straw to 3cm, then performing steam explosion, pressure maintaining time 6min, explosion pressure 1.3MPa; after discharging, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to the mass ratio of 1:2, then grinding and sieving to 80 meshes to obtain the modified composite fiber for standby use;

[0079] S3, preparing a liquid: taking 150g of magnesium chloride, 23g of the composite fire-retardant powder and 5.5g of the modified composite fiber by weight, then adding to 200g of water in sequence, and stirring uniformly to obtain the liquid;

[0080] S4, adding the liquid obtained in step S3 to a mold, and cold pressing (9MPa, 25℃, 8min) to obtain the fire-retardant board.

[0081] The preparation of the moisture-proof coating comprises the following steps:

[0082] Adding chitosan to 52wt% sodium hydroxide solution, and completely dissolving at 100℃; then adding PMMA, stirring uniformly, then adding ammonium persulfate and sorbitol, stirring and reacting at 50℃ for 3h to obtain a reactant solution; adding modified rectorite to the reactant solution, then adding KH550, and stirring at 30℃ for 1h to obtain the moisture-proof coating; wherein the amount ratio of chitosan to sodium hydroxide solution is 1g:14mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:18:0.035:0.005:0.5:0.09.

[0083] The preparation of the modified attapulgite includes the following steps: adding attapulgite into a 9wt% hydrochloric acid solution, stirring at 75 DEG C for 2h, and then performing filtration, washing and drying treatment.

[0084] Example 4

[0085] A preparation method of a multi-layer board, comprising the following steps:

[0086] (1) bonding and fixing a 2mm-thick fire-retardant board on the upper surface of a core layer by a first adhesive (the glue application amount is 120g / m 2 ) hot pressing (hot pressing pressure 12MPa, hot pressing temperature 180 DEG C, hot pressing time 8min); wherein the core layer is obtained by hot pressing (hot pressing pressure 13MPa, hot pressing temperature 180 DEG C, hot pressing time 10min) of 4 layers of 3mm-thick solid wood boards by a third adhesive (the glue application amount is 110g / m 2 );

[0087] (2) spraying 0.15mm moisture-proof paint on the lower surface of the core layer;

[0088] (3) bonding and fixing a 2mm-thick panel layer on the outer surface of the fire-retardant board by a second adhesive (the glue application amount is 110g / m 2 ) hot pressing (hot pressing pressure 10MPa, hot pressing temperature 180 DEG C, hot pressing time 6min).

[0089] The first adhesive, the second adhesive and the third adhesive are the same in composition and are obtained by mixing 65g of isocyanate adhesive and 8g of EVA emulsion by weight.

[0090] The preparation of the fire-retardant board comprises the following steps:

[0091] S1, preparing a composite fire-retardant powder: calcining vermiculite at 390 DEG C for 2h, and then grinding and sieving to 100 meshes; then adding into a 1.2mol / L acetic acid solution for treatment for 12h, and then performing filtration, washing and drying treatment to obtain material a; then, according to a mass ratio of 1:1.2, mixing the material a with hydrotalcite, and then adding into water, adding a mixed solution of 2.5wt% dodecylbenzenesulfonic acid sodium and 2.5wt% KH550 after stirring, and then stirring and reacting at 80 DEG C for 1h; after stirring is completed, performing filtration, washing and drying treatment to obtain the composite fire-retardant powder; wherein the amount ratio of vermiculite to the acetic acid solution is 1g:40mL, and the amount ratio of dodecylbenzenesulfonic acid sodium to hydrotalcite is 0.08:1;

[0092] S2, preparing modified composite fiber: pulverizing rice straw to 3 cm, then performing steam explosion, pressure maintaining time 6 min, explosion pressure 1.3 MPa; after unloading, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to a mass ratio of 1:2, then grinding and sieving to 80 meshes to obtain modified composite fiber, for standby use;

[0093] S3, preparing a material liquid: respectively taking 150 g of magnesium chloride, 25 g of composite flame-retardant powder and 6 g of modified composite fiber by weight, then sequentially adding into 200 g of water, stirring uniformly to obtain a material liquid;

[0094] S4, adding the material liquid obtained in step S3 into a mold, cold pressing (9 MPa, 25℃, 8 min) to obtain a flame-retardant plate.

[0095] Preparation of the moisture-proof coating includes the following steps:

[0096] Adding chitosan into a 50wt% sodium hydroxide solution, completely dissolving at 100℃; then adding PMMA, stirring uniformly, then adding ammonium persulfate and sorbitol, stirring and reacting at 50℃ for 3h to obtain a reactant solution; adding modified rectorite into the reactant solution, then adding KH550, stirring at 30℃ for 1h to obtain the moisture-proof coating; wherein the amount ratio of chitosan to sodium hydroxide solution is 1g:15mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:20:0.03:0.006:0.6:0.1.

[0097] Preparation of the modified rectorite includes the following steps: adding rectorite into a 9wt% hydrochloric acid solution, stirring at 75℃ for 2h, then filtering, washing and drying to obtain the modified rectorite.

[0098] Comparative Example 1

[0099] A method for preparing a multi-layer plate includes the following steps:

[0100] (1) hot pressing (hot pressing pressure 12 MPa, hot pressing temperature 180℃, hot pressing time 8 min) a 2mm-thick flame-retardant plate to the upper surface of a core layer by a first adhesive (glue coating amount 120g / m 2 ); wherein the core layer is obtained by hot pressing four 3mm-thick solid wood plates by a third adhesive (glue coating amount 110g / m 2 );

[0101] (2) spraying 0.15mm moisture-proof coating on the lower surface of the core layer;

[0102] The first adhesive and the third adhesive component are the same, and are obtained by mixing 65 g of isocyanate adhesive and 8 g of EVA emulsion by weight.

[0103] The preparation of the flame-retardant board comprises the following steps:

[0104] S1, preparing a composite flame-retardant powder: calcining vermiculite at 390℃ for 2h, then grinding and sieving to 100 meshes; then adding to 1.2 mol / L acetic acid solution for treatment for 12h, then filtering, washing and drying to obtain material a; then, according to a mass ratio of 1:1.2, mixing material a with hydrotalcite, then adding to water, then adding 5wt% KH550 solution after stirring, then stirring at 80℃ for 1h; after stirring, filtering, washing and drying, the composite flame-retardant powder is obtained; wherein the amount ratio of vermiculite to acetic acid solution is 1g:40mL, and the amount ratio of sodium dodecyl benzene sulfonate to hydrotalcite is 0.08:1;

[0105] S2, preparing a modified composite fiber: crushing water rice straw to 3cm, then performing steam explosion, pressure maintaining time 6min, explosion pressure 1.3MPa; after unloading, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to a mass ratio of 1:2, then grinding and sieving to 80 meshes to obtain the modified composite fiber for standby use;

[0106] S3, preparing a liquid: respectively taking 150g of magnesium chloride, 25g of the composite flame-retardant powder and 6g of the modified composite fiber by weight, then adding to 200g of water in sequence, then stirring uniformly to obtain the liquid;

[0107] S4, adding the liquid obtained in step S3 to a mold, then cold pressing (9MPa, 25℃, 8min) to press, thus obtaining the flame-retardant board.

[0108] The preparation of the moisture-proof coating comprises the following steps:

[0109] adding chitosan to 50wt% sodium hydroxide solution, completely dissolving at 100℃; then adding PMMA, stirring uniformly, then adding ammonium persulfate and sorbitol, stirring at 50℃ for 3h to obtain a reaction solution; adding modified rectorite to the reaction solution, then adding KH550, stirring at 30℃ for 1h, thus obtaining the moisture-proof coating; wherein the amount ratio of chitosan to sodium hydroxide solution is 1g:15mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:20:0.03:0.006:0.6:0.1.

[0110] The preparation of the modified rectorite comprises the following steps: adding rectorite to 9wt% hydrochloric acid solution, stirring at 75℃ for 2h, then filtering, washing and drying, thus obtaining the modified rectorite.

[0111] Compared with Example 1, the difference is that only KH550 was used to treat the composite flame retardant powder in Comparative Example 1, while the rest are the same.

[0112] Comparative Example 2

[0113] A method for preparing a multilayer board includes the following steps:

[0114] (1) Apply a 2mm thick flame-retardant board to the first adhesive (adhesive application amount is 120g / m). 2 The core material layer is bonded and fixed to the upper surface of the core material layer by hot pressing (hot pressing pressure 12MPa, hot pressing temperature 180℃, hot pressing time 8min); wherein, the core material layer is composed of 4 layers of solid wood boards with an equal thickness of 3mm, bonded together by a third adhesive (adhesive application amount of 110g / m). 2 Obtained by hot pressing;

[0115] (2) Spray a 0.15mm moisture-proof coating on the lower surface of the core material layer;

[0116] The first and third adhesives have the same components, and by weight, they are obtained by mixing 65g of isocyanate adhesive and 8g of EVA emulsion.

[0117] The preparation of the flame-retardant board includes the following steps:

[0118] S1. Preparation of flame-retardant powder: Vermiculite was calcined at 390℃ for 2 hours, then ground and sieved through a 100-mesh sieve; it was then added to a 1.2 mol / L acetic acid solution and treated for 12 hours, followed by filtration, washing, and drying to obtain material a; material a was then added to water, stirred, and a mixed solution of 2.5 wt% sodium dodecylbenzenesulfonate and 2.5 wt% KH550 was added, and the mixture was stirred at 80℃ for 1 hour; after stirring, it was filtered, washed, and dried to obtain the flame-retardant powder; wherein, the ratio of vermiculite to acetic acid solution was 1 g: 40 mL, and the ratio of sodium dodecylbenzenesulfonate to vermiculite was 0.08: 1;

[0119] S2. Preparation of modified composite fiber: Rice straw is crushed to 3cm and then subjected to steam explosion for 6min at an explosion pressure of 1.3MPa. After unloading, it is naturally air-dried to obtain straw material. Bamboo fiber and the straw material are mixed in a mass ratio of 1:2 and then ground and sieved through an 80-mesh sieve to obtain modified composite fiber for later use.

[0120] S3. Preparation of the liquid: Weigh 150g of magnesium chloride, 25g of flame retardant powder and 6g of modified composite fiber by weight, then add them to 200g of water and stir evenly to obtain the liquid.

[0121] S4, the material liquid obtained in step S3 is added into a mold, and cold pressing (9 MPa, 25℃, 8 min) is performed to obtain the flame-retardant plate.

[0122] The preparation of the moisture-proof coating comprises the following steps:

[0123] The chitosan is added into a 50wt% sodium hydroxide solution and completely dissolved at 100℃; then the PMMA is added, and after uniform stirring, the ammonium persulfate and sorbitol are added, and the stirring reaction is carried out at 50℃ for 3h to obtain a reactant solution; the modified rectorite is added into the reactant solution, and then the KH550 is added, and the stirring is carried out at 30℃ for 1h to obtain the moisture-proof coating; wherein the amount ratio of the chitosan to the sodium hydroxide solution is 1g:15mL, and the mass ratio of the chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 is 1:20:0.03:0.006:0.6:0.1.

[0124] The preparation of the modified rectorite comprises the following steps: the rectorite is added into a 9wt% hydrochloric acid solution, and after stirring at 75℃ for 2h, the filtration, washing and drying treatment are carried out to obtain the modified rectorite.

[0125] Compared with Example 1, the difference is that the flame-retardant powder in Comparative Example 2 does not contain hydrotalcite (the mass of hydrotalcite is replaced by the same mass of vermiculite), and the rest is the same.

[0126] Comparative Example 3

[0127] A preparation method of a multi-layer plate, comprising the following steps:

[0128] (1) the 2mm-thick flame-retardant plate is fixed on the upper surface of the core layer by hot pressing (hot pressing pressure 12MPa, hot pressing temperature 180℃, hot pressing time 8min) through the first adhesive (the amount of glue coating is 120g / m 2 ); wherein the core layer is obtained by hot pressing of 4 layers of 3mm-thick solid wood plates through the third adhesive (the amount of glue coating is 110g / m 2 );

[0129] (2) the moisture-proof coating of 0.15mm is sprayed on the lower surface of the core layer;

[0130] The first adhesive and the third adhesive are the same, and are obtained by mixing 65g of isocyanate adhesive and 8g of EVA emulsion by weight.

[0131] The preparation of the flame-retardant plate comprises the following steps:

[0132] S1, preparation of composite flame-retardant powder: vermiculite was calcined at 390°C for 2h, then ground and sieved to 100 mesh; then added to 1.2 mol / L acetic acid solution for 12h, then filtered, washed and dried to obtain material a; then, according to the mass ratio of 1:1.2, material a and hydrotalcite were mixed, then added to water, after stirring, a mixed solution of 2.5wt% dodecylbenzenesulfonic acid sodium and 2.5wt% KH550 was added, then stirred at 80°C for 1h; after stirring, it was filtered, washed and dried to obtain the composite flame-retardant powder; wherein the amount ratio of vermiculite to acetic acid solution was 1g:40mL, and the amount ratio of dodecylbenzenesulfonic acid sodium to hydrotalcite was 0.08:1;

[0133] S2, preparation of modified fiber: rice straw was crushed to 3cm and then subjected to steam explosion, with a holding time of 6min and an explosion pressure of 1.3MPa; after unloading, it was naturally dried to obtain straw material; the straw material was ground and sieved to 80 mesh to obtain modified fiber for standby;

[0134] S3, preparation of liquid: 150g of magnesium chloride, 25g of composite flame-retardant powder and 6g of modified fiber were weighed according to weight, then added to 200g of water in sequence and stirred uniformly to obtain a liquid;

[0135] S4, the liquid obtained in step S3 was added to a mold and cold-pressed (9MPa, 25°C, 8min) to obtain a flame-retardant board.

[0136] The preparation of the moisture-proof coating includes the following steps:

[0137] Chitosan was added to a 50wt% sodium hydroxide solution and completely dissolved at 100°C; then PMMA was added, stirred uniformly, and then ammonium persulfate and sorbitol were added, stirred at 50°C for 3h to obtain a reactant solution; modified rectorite was added to the reactant solution, and then KH550 was added, stirred at 30°C for 1h to obtain the moisture-proof coating; wherein the amount ratio of chitosan to sodium hydroxide solution was 1g:15mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified rectorite and KH550 was 1:20:0.03:0.006:0.6:0.1.

[0138] The preparation of the modified rectorite includes the following steps: rectorite was added to a 9wt% hydrochloric acid solution, stirred at 75°C for 2h, then filtered, washed and dried to obtain the modified rectorite.

[0139] Compared with Example 1, the difference is that the modified fiber in Comparative Example 3 does not contain bamboo fiber (the mass of bamboo fiber is replaced by the same mass of rice straw), and the rest is the same.

[0140] Comparative Example 4

[0141] A method for preparing a multi-layer board, comprising the following steps:

[0142] (1) bonding and fixing a 2mm-thick fire-retardant board to the upper surface of a core layer by a first adhesive (glue application amount: 120g / m 2 ) hot pressing (hot pressing pressure: 12MPa, hot pressing temperature: 180℃, hot pressing time: 8min); wherein the core layer is obtained by hot pressing four 3mm-thick solid wood boards with equal thickness by a third adhesive (glue application amount: 110g / m 2 );

[0143] (2) spraying 0.15mm moisture-proof paint on the lower surface of the core layer;

[0144] wherein the first adhesive and the third adhesive are the same and are obtained by mixing 65g of isocyanate adhesive and 8g of EVA emulsion by weight.

[0145] wherein the preparation of the fire-retardant board comprises the following steps:

[0146] S1, preparing a composite fire-retardant powder: calcining vermiculite at 390℃ for 2h, then grinding and sieving to 100 meshes; then adding to 1.2mol / L acetic acid solution for 12h, then filtering, washing and drying to obtain material a; then mixing material a with hydrotalcite according to a mass ratio of 1:1.2, then adding to water, then adding a mixed solution of 2.5wt% sodium dodecyl benzene sulfonate and 2.5wt% KH550 after stirring, then stirring at 80℃ for 1h; after stirring, filtering, washing and drying, the composite fire-retardant powder is obtained; wherein the amount ratio of vermiculite to acetic acid solution is 1g:40mL, and the amount ratio of sodium dodecyl benzene sulfonate to hydrotalcite is 0.08:1;

[0147] S2, preparing a modified composite fiber: crushing rice straw to 3cm, then performing steam explosion, pressure maintaining time: 6min, explosion pressure: 1.3MPa; after discharging, naturally air-drying to obtain straw material; mixing bamboo fiber and the straw material according to a mass ratio of 1:2, then grinding and sieving to 80 meshes to obtain the modified composite fiber for standby use;

[0148] S3, preparing a liquid: taking 150g of magnesium chloride, 25g of the composite fire-retardant powder and 6g of the modified composite fiber by weight, then adding to 200g of water in sequence, then stirring uniformly to obtain the liquid;

[0149] S4, adding the liquid obtained in step S3 to a mold, then cold pressing (9MPa, 25℃, 8min) to obtain the fire-retardant board.

[0150] wherein the preparation of the moisture-proof paint comprises the following steps:

[0151] Chitosan is added into 50wt% sodium hydroxide solution, and is completely dissolved at 100 DEG C; then PMMA is added, after stirring uniformly, ammonium persulfate and sorbitol are added, and stirring reaction is carried out at 50 DEG C for 3h, to obtain a reactant solution; then attapulgite is added into the reactant solution, and KH550 is added, and stirring is carried out at 30 DEG C for 1h, to obtain the moisture-proof coating; wherein the usage ratio of chitosan and sodium hydroxide solution is 1g:15mL, and the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, attapulgite and KH550 is 1:20:0.03:0.006:0.6:0.1.

[0152] Compared with example 1, the difference is that the attapulgite is not modified in comparative example 4, and the rest is the same.

[0153] The flame-retardant board and the moisture-proof coating prepared in example 1 and comparative examples 1-4 are subjected to performance test, and the test results are shown in table 1 and table 2.

[0154] The flame-retardant performance of the prepared flame-retardant board is tested, and the test method refers to GB / T 8625-2005.

[0155] The performance of the prepared moisture-proof coating is tested, and the test is as follows: equal specifications and equal quality small wood blocks are smeared with equal quality moisture-proof coating prepared in example 1 and example 4, and are dried at 125 DEG C for 1.5h, and then are weighed; then each small wood block is immersed in deionized water for 24h, and after wiping the surface water, is weighed again, and the net weight gain is calculated.

[0156] Table 1: flame-retardant test results

[0157]

[0158] Table 2: moisture-proof performance test results

[0159] Initial weight / g Soak weight gain / g Example 1 600 0.6 Comparative Example 4 600 5.8

[0160] From table 1 and table 2, it can be seen that the moisture-proof performance of the prepared moisture-proof coating is good, and the flame-retardant performance of the prepared flame-retardant board is good, and the comprehensive performance of the multi-layer board is excellent.

[0161] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a multilayer board, characterized in that, Includes the following steps: (1) The flame-retardant board is hot-pressed and fixed to the upper surface of the core material layer using the first adhesive; (2) Spray a moisture-proof coating on the lower surface of the core material layer; The preparation of the flame-retardant board includes the following steps: S1. Preparation of composite flame retardant powder: Vermiculite is calcined at 350~420℃ for 1~4h, then ground and sieved through an 80~120 mesh; then it is added to an acetic acid solution for 8~16h, followed by filtration, washing, and drying to obtain material a; then, material a is mixed with hydrotalcite at a mass ratio of 1:0.5~2, then added to water, stirred, and a mixed solution of sodium dodecylbenzenesulfonate and KH550 is added, followed by stirring and reaction at 75~85℃ for 0.5~2h; after stirring, it is filtered, washed, and dried to obtain the composite flame retardant powder; S2. Preparation of modified composite fiber: Rice straw is crushed to 1.5~3.5cm and then subjected to steam explosion for 3~8min at an explosion pressure of 1.2~1.4MPa; after unloading, it is naturally air-dried to obtain straw material; bamboo fiber and the straw material are mixed in a mass ratio of 1:1.5~2.5 and then ground and sieved through a 50~100 mesh to obtain modified composite fiber for later use; S3. Preparation of the liquid: Weigh 100-200 parts by weight of magnesium chloride, 15-30 parts by weight of composite flame retardant powder and 5-12 parts by weight of modified composite fiber, and then add them to 150-300 parts by weight of water, stir evenly to obtain the liquid. S4. Add the liquid material obtained in step S3 into the mold and press it with cold to obtain the flame retardant board.

2. The method for preparing a multilayer board according to claim 1, characterized in that, Also includes: The panel layer is fixed to the outer surface of the flame-retardant board by hot pressing with a second adhesive. The core material layer is obtained by hot pressing no less than three layers of solid wood boards of equal thickness together with a third adhesive.

3. The method for preparing a multilayer board according to claim 2, characterized in that, The thickness of the panel layer is 1~6mm, the thickness of the flame retardant board is 1~2.5mm, the thickness of the core material layer is 8~15mm, and the thickness of the moisture-proof coating is 0.1~0.2mm.

4. The method for preparing a multilayer board according to claim 2, characterized in that, The application amount of the first, second, and third adhesives is 80~150g / m². 2 ; The first, second, and third adhesives have the same composition, and are obtained by mixing 6.5 parts isocyanate adhesive and 0.8 parts EVA emulsion by weight.

5. The method for preparing a multilayer board according to claim 2, characterized in that, The hot pressing pressure for hot pressing the flame-retardant board to the upper surface of the core material layer is 9~13MPa, the hot pressing temperature is 175~185℃, and the hot pressing time is 4~10min. The hot pressing pressure for hot-pressing the panel layer to the outer surface of the flame-retardant board is 8~12MPa, the hot pressing temperature is 175~185℃, and the hot pressing time is 5~10min. Solid wood boards are hot-pressed with a third adhesive at a pressure of 10-15 MPa, a temperature of 175-185°C, and a time of 5-15 minutes.

6. The method for preparing a multilayer board according to claim 1, characterized in that, In step S1, the concentration of the acetic acid solution is 1~1.5 mol / L, the ratio of vermiculite to acetic acid solution is 1 g: 30~50 mL; the mass ratio of sodium dodecylbenzenesulfonate to KH550 is 1:1, the concentration of sodium dodecylbenzenesulfonate is 1.5~3.5 wt%; and the ratio of sodium dodecylbenzenesulfonate to hydrotalcite is 0.06~0.12:

1. In step S4, the cold pressing pressure is 6~12MPa, the cold pressing temperature is 23~25℃, and the cold pressing time is 6~15min.

7. The method for preparing a multilayer board according to claim 1, characterized in that, The preparation of moisture-proof coatings includes the following steps: Chitosan was added to sodium hydroxide solution and completely dissolved at 95-105℃; then PMMA was added, stirred evenly, and then ammonium persulfate and sorbitol were added. The mixture was stirred at 45-55℃ for 1-4 hours to obtain the reaction solution. Modified attapulgite is added to the reactant solution, followed by KH550. The mixture is stirred at 25-35°C for 0.5-2 hours to obtain a moisture-proof coating.

8. The method for preparing a multilayer board according to claim 7, characterized in that, The concentration of sodium hydroxide solution is 45~55wt%, and the ratio of chitosan to sodium hydroxide solution is 1g:12~18mL; the mass ratio of chitosan, PMMA, ammonium persulfate, sorbitol, modified attapulgite, and KH550 is 1:10~40:0.02~0.06:0.004~0.01:0.5~0.8:0.08~0.

15.

9. The method for preparing a multilayer board according to claim 7, characterized in that, The preparation of the modified retardite includes the following steps: adding retardite to a 7-12 wt% hydrochloric acid solution, stirring at 65-85℃ for 0.5-4 hours, then filtering, washing, and drying to obtain the product.

10. The multilayer board prepared by the method according to any one of claims 1 to 9.

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