A high-strength composite board for construction and its preparation method

Abstract

The present invention discloses a high-strength composite board for construction and its preparation method, belonging to the technical field of composite board processing. The present invention is used to solve the technical problems that in the prior art, the fire resistance of the composite board needs to be further improved, and the adhesive between multiple high-strength heat-resistant layers adhered together is prone to denaturation and separation from the high-strength heat-resistant layers in a humid and hot environment. A high-strength composite board for construction includes a composite board main body, and the composite board main body includes an upper high-strength heat-resistant layer, a middle high-strength heat-resistant layer, and a lower high-strength heat-resistant layer arranged in sequence from top to bottom. The upper high-strength heat-resistant layer, the middle high-strength heat-resistant layer, and the lower high-strength heat-resistant layer are adhered through an adhesive. By the mutual cooperation of the modified enhancer and the adhesive, the present invention not only effectively improves the fire resistance of multiple high-strength heat-resistant layers constituting the composite board, but also effectively improves the adhesion stability between multiple high-strength heat-resistant layers, thereby improving the strength and fire resistance of the composite board main body.

Description

Technical Field

[0001] The present invention relates to the technical field of composite board processing, and particularly relates to a high-strength composite board for construction and a preparation method thereof. Background Art

[0002] With the rapid development of economy and technology, the national urbanization level has gradually increased, and buildings have become taller and more concentrated. During the building decoration process, composite boards are usually used to decorate houses. Traditional composite boards are usually made of fibers as raw materials, with thermosetting resins applied and pressed into a board under heating and pressure conditions. Due to their good mechanical properties, composite boards are widely used in the construction of various houses and walls.

[0003] The composite boards in the prior art are usually composed of multiple high-strength heat-resistant layers processed from refractory materials. However, the fire resistance of this composite board is limited by the refractory properties of the materials themselves. Therefore, the fire resistance limit of the composite board is relatively low, and its performance is greatly reduced. The strength of each individual high-strength heat-resistant layer that makes up the composite board is relatively poor. To ensure the strength of the composite board, adhesives are usually used to bond multiple high-strength heat-resistant layers together. The composite board has a relatively large density, and traditional adhesives can only bond the high-strength heat-resistant layers together. When the composite board is in a humid and hot environment for a long time, the adhesive is prone to denaturation and separation from the composite board, resulting in the separation and damage of multiple high-strength heat-resistant layers that make up the composite board. The strength of the composite board needs to be further improved.

[0004] In view of this technical defect, a solution is proposed herein. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength composite board for construction and a preparation method thereof, aiming to solve the technical problems in the prior art that the fire resistance of the composite board is limited by the materials and needs to be further improved, and the adhesive between multiple high-strength heat-resistant layers bonded together is prone to denaturation and separation from the high-strength heat-resistant layers in a humid and hot environment, and the strength of the composite board needs to be further improved.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A high-strength composite board for construction, comprising a composite board main body. The composite board main body includes an upper high-strength heat-resistant layer, a middle high-strength heat-resistant layer, and a lower high-strength heat-resistant layer arranged in sequence from top to bottom. The upper high-strength heat-resistant layer, the middle high-strength heat-resistant layer, and the lower high-strength heat-resistant layer are adhered to each other through an adhesive. The upper high-strength heat-resistant layer, the middle high-strength heat-resistant layer, and the lower high-strength heat-resistant layer are all composed of magnesium oxide, magnesium chloride, gypsum powder, a modified reinforcing agent, a plasticizer, and a modified cross-linking agent according to a weight ratio of 20-30:15-20:10-15:4-8:0.4-0.6:8-12. Among them, the plasticizer is tris(2-ethylhexyl) phosphate;

[0008] The modified cross-linking agent is obtained by polymerizing the hydroxyl group on 1-phenyl-1,2-butanediol and the isocyanate group of isophorone diisocyanate under the condition of a catalyst to generate a product with isocyanate groups at both ends, carrying out a chain extension reaction with 4,4'-diamino-3,3'-dichlorodiphenylmethane to increase the molecular chain of the product, and then grafting with the amino group on melamine. The adhesive is obtained by concentrating the modified cross-linking agent under reduced pressure to remove dimethyl sulfoxide.

[0009] Furthermore, a plurality of convex portions in a net structure are fixedly connected to one side of the upper high-strength heat-resistant layer and the lower high-strength heat-resistant layer close to the middle high-strength heat-resistant layer. Grooves matched with the convex portions are formed on both sides of the middle high-strength heat-resistant layer, and a plurality of holes are formed in the middle high-strength heat-resistant layer, and sound-absorbing cotton is filled in the plurality of holes.

[0010] A preparation method of a high-strength composite board for construction, comprising the following operation steps:

[0011] S1. Weigh 2-4 parts by weight of glass fiber and 2-4 parts by weight of silicon dioxide powder, place the glass fiber and the silicon dioxide powder in a muffle furnace, heat them at 550-600 °C for 1-2 h, and naturally cool them to room temperature. Wash them with deionized water to obtain the washed glass fiber and the washed silicon dioxide;

[0012] The oily impurities adhering to the outer surfaces of the glass fiber and the silicon dioxide powder are burned and carbonized by burning, and then washed with deionized water, so as to clean the outer surface of the glass fiber.

[0013] S2. Add dopamine and deionized water to a beaker and stir to dissolve them to prepare a mixed solution with a concentration of 30-50 g / L. Add tris(hydroxymethyl)aminomethane hydrochloride to the mixed solution to adjust the pH of the system to 8.5-9 to obtain a dopamine aqueous solution;

[0014] S3. Weigh 40-60 parts by weight of the dopamine aqueous solution, the washed glass fiber, and the washed silicon dioxide, add them to a beaker and stir, react at room temperature for 24-26 h, and carry out post-treatment to obtain a modified reinforcing agent;

[0015] Reaction principle: Dopamine self-polymerizes under alkaline conditions to form polydopamine. Polydopamine has strong adhesiveness and wraps around the outside of glass fiber or silica to form a modified reinforcing agent.

[0016] S4. Weigh 20 - 30 parts of magnesium oxide, 15 - 20 parts of magnesium chloride, 10 - 15 parts of gypsum powder, 4 - 8 parts of modified reinforcing agent, 0.4 - 0.6 parts of tris(2-ethylhexyl) phosphate, and 8 - 12 parts of modified crosslinking agent by weight, add them to a beaker and stir for 60 - 80 min to obtain a mixture.

[0017] S5. Add the mixture to a prefabricated mold, raise the mold temperature to 80 - 100 °C, keep it warm and hot press for 30 - 50 min to form a high-strength heat-resistant layer.

[0018] S6. Take three high-strength heat-resistant layers, evenly coat an adhesive between two adjacent high-strength heat-resistant layers, and bond the three high-strength heat-resistant layers together to obtain a composite board.

[0019] Further, the post-treatment operation in step S3 is as follows: After the reaction is completed, filter, wash the filter cake with deionized water and then drain it, place the filter cake in a drying oven at 60 - 70 °C and dry for 10 - 12 h to obtain a modified reinforcing agent.

[0020] Further, in step S6 operation, a plurality of holes are provided in the high-strength heat-resistant layer located between the three high-strength heat-resistant layers, and sound-absorbing cotton is filled in the holes. After evenly coating an adhesive on the outer walls of the mutually adjacent sides of the three high-strength heat-resistant layers, horizontally place them in an oven at 80 - 100 °C and press for 20 - 30 min, and the pressure on the top of the three high-strength heat-resistant layers is 2 - 3 MPa.

[0021] Further, the modified crosslinking agent is prepared by the following operation steps:

[0022] A1. Add 1-phenyl-1,2-butanediol and isophorone diisocyanate to a three-necked flask and stir. Under nitrogen protection, raise the temperature of the three-necked flask to 80 - 90 °C, add a catalyst to the three-necked flask, and react for 2 - 3 h to obtain intermediate I.

[0023] The reaction principle is as follows: Under the condition of a catalyst, the hydroxyl group on 1-phenyl-1,2-butanediol and the isocyanate group on isophorone diisocyanate undergo an addition reaction to obtain intermediate I with isocyanate groups at both ends.

[0024] A2. Add a 4,4'-diamino-3,3'-dichlorodiphenylmethane solution to the three-necked flask containing intermediate I and react for 2 - 3 h to obtain intermediate II.

[0025] The reaction principle is as follows: The amino group on 4,4'-diamino-3,3'-dichlorodiphenylmethane reacts with the isocyanate group on intermediate I to form urea, which plays a role in extending the molecular chain, increasing the molecular weight of intermediate II, and the two ends of intermediate II are still isocyanate groups.

[0026] A3. Add the melamine solution to the three-necked flask containing intermediate II, react for 2 - 3 h, pour out the reaction solution, and cool it to room temperature to obtain the adhesive.

[0027] The reaction principle is as follows: The isocyanate group on intermediate II reacts with the amino group on melamine to form urea. Three intermediate II molecules are grafted onto melamine, and the end of intermediate II far from melamine is still an isocyanate group.

[0028] Further, the catalyst in step A1 is any one of dibutyltin dilaurate, stannous octoate, zinc octoate, and bismuth octoate, and the molar ratio of 1-phenyl-1,2-butanediol to isophorone diisocyanate is 1:2.1 - 2.2.

[0029] Further, the molar ratio of 4,4'-diamino-3,3'-dichlorodiphenylmethane to 1-phenyl-1,2-butanediol is 0.3 - 0.5:1. The 4,4'-diamino-3,3'-dichlorodiphenylmethane solution is a mixed solution of 4,4'-diamino-3,3'-dichlorodiphenylmethane and dimethyl sulfoxide, wherein the mass concentration of 4,4'-diamino-3,3'-dichlorodiphenylmethane is 30 - 40%.

[0030] Further, the molar ratio of melamine to 1-phenyl-1,2-butanediol is 0.2 - 0.3:1. The melamine solution is a mixed solution of melamine and dimethyl sulfoxide, wherein the mass concentration of melamine is 40 - 50%.

[0031] Further, the modified cross-linking agent is placed in a flask, the temperature of the flask is raised to 110 - 120 °C, and vacuum distillation is carried out until no liquid flows out to obtain the adhesive.

[0032] The present invention has the following beneficial effects:

[0033] 1. The composite board in the present invention is composed of an upper high-strength heat-resistant layer, a middle high-strength heat-resistant layer, a lower high-strength heat-resistant layer and an adhesive. Through the holes opened in the middle high-strength heat-resistant layer, the weight of the composite board is effectively reduced. The sound-absorbing cotton filled in the holes can improve the sound insulation effect of the composite board. The adhesive and the adjacent two high-strength heat-resistant layers are bonded together by urea bonds, making the composite board a stable whole. A large number of benzene rings and melamine are grafted on the adhesive, which has good heat resistance, thereby improving the bonding performance between multiple high-strength heat-resistant layers on the composite board.

[0034] 2. The multiple high-strength heat-resistant layers that make up the main body of the composite board in the present invention are all composed of magnesium oxide, magnesium chloride, gypsum powder, a modified reinforcing agent, tris(2-ethylhexyl) phosphate and a modified crosslinking agent. Each component has good heat resistance and flame retardancy. By modifying the reinforcing agent, a layer of polydopamine is wrapped on the outside of glass fiber and silicon dioxide. While enhancing glass fiber and silicon dioxide, a large number of amino groups are grafted on the outside of glass fiber and silicon dioxide. The end of the modified crosslinking agent is grafted with an isocyanate group. During the hot pressing process, the amino group and the isocyanate group combine together, thereby forming a tight three-dimensional network structure with the modified reinforcing agent as the connection point during the curing process of the high-strength heat-resistant layer, thus improving the static bending strength, elastic modulus and maximum failure load of the composite board.

[0035] 3. A large number of benzene rings and melamine are grafted on the modified crosslinking agent in the present invention. Both benzene rings and melamine have good heat resistance. Moreover, melamine decomposes to produce a network polymer when heated, greatly increasing the char yield of the polymer and affecting its melting behavior, thereby effectively improving the heat resistance of the modified crosslinking agent. When the composite board is heated, it can still maintain good bonding stability and improve the heat resistance of the composite board. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic structural diagram of the composite board before adhesion in the present invention;

[0038] Figure 2 It is a schematic structural diagram of the composite board after adhesion in the present invention;

[0039] Figure 3 It is a front view sectional structural diagram of the composite board in the present invention.

[0040] In the figure: 101, upper high-strength heat-resistant layer; 102, middle high-strength heat-resistant layer; 103, lower high-strength heat-resistant layer; 104, holes; 105, grooves; 106, protrusions. Specific embodiments

[0041] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. 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.

[0042] Embodiment 1

[0043] As Figures 1-3 shown, a high-strength composite board for construction in this embodiment includes a composite board main body. The composite board main body includes an upper high-strength heat-resistant layer 101, a middle high-strength heat-resistant layer 102, and a lower high-strength heat-resistant layer 103 arranged in sequence from top to bottom. The upper high-strength heat-resistant layer 101, the middle high-strength heat-resistant layer 102, and the lower high-strength heat-resistant layer 103 are adhered to each other through an adhesive. On the side of the upper high-strength heat-resistant layer 101 and the lower high-strength heat-resistant layer 103 close to the middle high-strength heat-resistant layer 102, a plurality of protrusions 106 in a net structure are fixedly connected. On both sides of the middle high-strength heat-resistant layer 102, grooves 105 are provided to cooperate with the protrusions 106, and a plurality of holes 104 are provided on the middle high-strength heat-resistant layer 102, and sound-absorbing cotton is filled in the plurality of holes 104.

[0044] The upper high-strength heat-resistant layer 101, the middle high-strength heat-resistant layer 102, and the lower high-strength heat-resistant layer 103 are each composed of 80 g of magnesium oxide, 60 g of magnesium chloride, 40 g of gypsum powder, 16 g of a modified reinforcing agent, 1.6 g of tris(2-ethylhexyl) phosphate, and 32 g of a modified cross-linking agent. After being uniformly mixed, they are added to a mold at a temperature of 80 °C and hot-pressed for 30 minutes at a pressure of 3 MPa to form.

[0045] The modified cross-linking agent is obtained by polymerizing the hydroxyl group on 1-phenyl-1,2-butanediol and the isocyanate group on isophorone diisocyanate to form a product with isocyanate groups at both ends under the condition of a catalyst, followed by a chain extension reaction with 4,4'-diamino-3,3'-dichlorodiphenylmethane to increase the molecular chain of the product, and then grafting with the amino group on melamine. The adhesive is obtained by subjecting the modified cross-linking agent to reduced pressure concentration to remove dimethyl sulfoxide.

[0046] Multiple protrusions 106 cooperate with the grooves 105, which can effectively increase the bonding area between the upper high-strength heat-resistant layer 101, the middle high-strength heat-resistant layer 102, and the lower high-strength heat-resistant layer 103, and limit the positions between two adjacent high-strength heat-resistant layers, preventing dislocation and separation between the upper high-strength heat-resistant layer 101, the middle high-strength heat-resistant layer 102, and the lower high-strength heat-resistant layer 103. Multiple holes 104 provided on the middle high-strength heat-resistant layer 102 can effectively reduce the overall density of the composite board body, and the sound-absorbing cotton filled in the holes 104 can effectively improve the sound insulation performance of the composite board body.

[0047] Example 2

[0048] A preparation method of a high-strength composite board for buildings in this embodiment includes the following operation steps:

[0049] Prepare a modified reinforcing agent:

[0050] Weigh 20 g of glass fiber and 20 g of silica powder by weight. Place the glass fiber and silica powder into a muffle furnace and heat them at 550 °C for 1 h, then naturally cool them to room temperature. Wash them with deionized water to obtain the washed glass fiber and the washed silica.

[0051] Add 30 g of dopamine and deionized water to a beaker and stir to dissolve, preparing a mixed solution with a concentration of 30 g / L. Dropwise add tris(hydroxymethyl)aminomethane hydrochloride to the mixed solution to adjust the pH of the system to 8.5 to obtain an aqueous dopamine solution.

[0052] Weigh 400 g of the aqueous dopamine solution and 40 g of the washed glass fiber and the washed silica, add them to a beaker and stir. React at room temperature for 24 h. After the reaction is completed, filter. The filter cake is rinsed with deionized water and then dried by suction. The filter cake is placed in a drying oven at 60 °C and dried for 10 h to obtain a modified reinforcing agent.

[0053] Prepare a modified cross-linking agent:

[0054] Add 16.6 g of 1-phenyl-1,2-butanediol and 46.6 of isophorone diisocyanate to a three-necked flask and stir. Under nitrogen protection, raise the temperature of the three-necked flask to 80 °C, add 0.2 g of dibutyltin dilaurate to the three-necked flask, and react for 2 h to obtain intermediate I;

[0055] Weigh 8.0 g of 4,4'-diamino-3,3'-dichlorodiphenylmethane and mix and dissolve it with 18.6 g of dimethyl sulfoxide. Add it to the three-necked flask containing intermediate I and react for 2 h to obtain intermediate II;

[0056] Weigh 2.5 g of melamine and mix it with 3.8 g of dimethyl sulfoxide until it is completely dissolved. Then add it to a three-necked flask containing Intermediate II and react for 2 h. Pour out the reaction solution and cool it to room temperature to obtain the modified crosslinking agent.

[0057] Prepare a high-strength heat-resistant layer:

[0058] Weigh 80 g of magnesium oxide, 60 g of magnesium chloride, 40 g of gypsum powder, 16 g of modified reinforcing agent, 1.6 g of tris(2-ethylhexyl) phosphate, and 32 g of modified crosslinking agent by weight, add them to a beaker and stir for 60 min to obtain a mixture.

[0059] Add the mixture to a prefabricated mold, raise the mold temperature to 80 °C, keep it warm and hot-press for 30 min to form, and obtain a high-strength heat-resistant layer.

[0060] Prepare a composite board:

[0061] Place the modified crosslinking agent in a flask, raise the flask temperature to 110 - 120 °C and distill it under reduced pressure until no liquid flows out to obtain an adhesive.

[0062] Take three high-strength heat-resistant layers, evenly coat the adhesive between two adjacent high-strength heat-resistant layers, stick the three high-strength heat-resistant layers together to obtain a composite board. Open multiple holes in the high-strength heat-resistant layer located between the three high-strength heat-resistant layers, fill the holes with sound-absorbing cotton. After evenly coating the adhesive on the outer walls of the mutually adjacent sides of the three high-strength heat-resistant layers, place them horizontally in an oven at 80 °C and press them for 20 min. The pressure on the top of the three high-strength heat-resistant layers is 2 MPa.

[0063] Example 3

[0064] A preparation method of a high-strength composite board for construction in this example includes the following operation steps:

[0065] Prepare a modified reinforcing agent:

[0066] Weigh 30 g of glass fiber and 30 g of silicon dioxide powder by weight. Place the glass fiber and silicon dioxide powder in a muffle furnace and heat them at 580 °C for 1.5 h, then cool them naturally to room temperature, and wash them with deionized water to obtain the washed glass fiber and the washed silicon dioxide.

[0067] Add 40 g of dopamine and deionized water to a beaker and stir to dissolve, prepare a mixed solution with a concentration of 40 g / L. Add tris(hydroxymethyl)aminomethane hydrochloride to the mixed solution to adjust the pH of the system to 8.8 to obtain an aqueous dopamine solution.

[0068] Weigh 500 g of dopamine aqueous solution, the cleaned glass fiber, and 60 g of the cleaned silica, add them to a beaker and stir. React at room temperature for 25 h. After the reaction is completed, filter. The filter cake is rinsed with deionized water and then dried by suction. The filter cake is placed in an oven at 65 °C and dried for 11 h to obtain a modified reinforcing agent;

[0069] Prepare a modified crosslinking agent:

[0070] Add 16.6 g of 1-phenyl-1,2-butanediol and 47.7 g of isophorone diisocyanate to a three-necked flask and stir. Under nitrogen protection, the temperature of the three-necked flask is raised to 85 °C. Add 0.2 g of stannous octoate to the three-necked flask and react for 2.5 h to obtain Intermediate I;

[0071] Weigh 10.6 g of 4,4'-diamino-3,3'-dichlorodiphenylmethane and mix it with 19.6 g of dimethyl sulfoxide until clear. Add it to the three-necked flask containing Intermediate I and react for 2.5 h to obtain Intermediate II;

[0072] Weigh 3.2 g of melamine and 3.9 g of dimethyl sulfoxide and mix them until clear. Add it to the three-necked flask containing Intermediate II and react for 2.5 h. Pour out the reaction solution and cool it to room temperature to obtain a modified crosslinking agent.

[0073] Prepare a high-strength heat-resistant layer:

[0074] Weigh 100 g of magnesium oxide, 70 g of magnesium chloride, 50 g of gypsum powder, 24 g of the modified reinforcing agent, 2 g of tris(2-ethylhexyl) phosphate, and 40 g of the modified crosslinking agent according to parts by weight, add them to a beaker and stir for 70 min to obtain a mixture;

[0075] Add the mixture to a prefabricated mold, raise the temperature of the mold to 90 °C, keep it warm and hot-press for 40 min to form a high-strength heat-resistant layer.

[0076] Prepare a composite board:

[0077] Place the modified crosslinking agent in a flask, raise the temperature of the flask to 110 - 120 °C and distill under reduced pressure until no liquid flows out to obtain an adhesive;

[0078] Take three high-strength heat-resistant layers, evenly coat the adhesive between two adjacent high-strength heat-resistant layers, bond the three high-strength heat-resistant layers together to obtain a composite board. A plurality of holes are provided in the high-strength heat-resistant layer located between the three high-strength heat-resistant layers, and sound-absorbing cotton is filled in the holes. After the outer walls of the three high-strength heat-resistant layers adjacent to each other are evenly coated with the adhesive, they are horizontally placed in an oven at 90 °C and pressed for 25 min, and the pressure on the top of the three high-strength heat-resistant layers is 2.5 MPa.

[0079] Example 4

[0080] A preparation method of a high-strength composite board for construction in this embodiment includes the following operating steps:

[0081] Prepare a modified reinforcing agent:

[0082] Weigh 40 g of glass fiber and 40 g of silicon dioxide powder by weight. Place the glass fiber and silicon dioxide powder into a muffle furnace and heat them at 600 °C for 2 h. Naturally cool them to room temperature, and wash them with deionized water to obtain the washed glass fiber and the washed silicon dioxide.

[0083] Add 50 g of dopamine and deionized water to a beaker and stir to dissolve, preparing a mixed solution with a concentration of 50 g / L. Add tris(hydroxymethyl)aminomethane hydrochloride to the mixed solution to adjust the pH of the system to 9 to obtain an aqueous dopamine solution.

[0084] Weigh 600 g of the aqueous dopamine solution, the washed glass fiber, and the washed silicon dioxide, add 80 g to a beaker and stir. React at room temperature for 26 h. After the reaction is completed, filter. The filter cake is rinsed with deionized water and then dried by suction. The filter cake is placed in a drying oven at 70 °C and dried for 12 h to obtain a modified reinforcing agent.

[0085] Prepare a modified crosslinking agent:

[0086] Add 16.6 g of 1-phenyl-1,2-butanediol and 48.8 g of isophorone diisocyanate to a three-necked flask and stir. Under nitrogen protection, raise the temperature of the three-necked flask to 90 °C, add 0.2 g of bismuth isooctanoate to the three-necked flask, and react for 3 h to obtain intermediate I;

[0087] Weigh 13.3 g of 4,4'-diamino-3,3'-dichlorodiphenylmethane and 20.0 g of dimethyl sulfoxide and mix them until clear. Add them to the three-necked flask containing intermediate I and react for 3 h to obtain intermediate II;

[0088] Weigh 3.8 g of melamine and 3.8 g of dimethyl sulfoxide and mix them until clear. Add them to the three-necked flask containing intermediate II and react for 3 h. Pour out the reaction solution and cool it to room temperature to obtain a modified crosslinking agent.

[0089] Prepare a high-strength heat-resistant layer:

[0090] Weigh 120 g of magnesium oxide, 80 g of magnesium chloride, 60 g of gypsum powder, 32 g of modified reinforcing agent, 2.4 g of tris(2-ethylhexyl) phosphate, and 48 g of modified crosslinking agent by weight, add them to a beaker and stir for 80 min to obtain a mixture;

[0091] Add the mixture to a prefabricated mold, raise the temperature of the mold to 100 °C, keep it warm and hot press for 50 min to form, and obtain a high-strength heat-resistant layer.

[0092] Preparation of composite board:

[0093] Place the modified crosslinking agent into a flask, raise the temperature of the flask to 110 - 120 °C, and distill under reduced pressure until no liquid flows out to obtain an adhesive.

[0094] Take three high-strength heat-resistant layers, evenly coat the adhesive between two adjacent high-strength heat-resistant layers, bond the three high-strength heat-resistant layers together to obtain a composite board. A plurality of holes are provided in the high-strength heat-resistant layer located between the three high-strength heat-resistant layers, and sound-absorbing cotton is filled in the holes. After evenly coating the adhesive on the outer walls of the three high-strength heat-resistant layers close to each other, place them horizontally in an oven at 100 °C and press for 30 min. The pressure on the top of the three high-strength heat-resistant layers is 3 MPa.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 4 is that the modified crosslinking agent is an epoxy resin adhesive.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 4 is that neither the glass fiber nor the silicon dioxide powder has been modified.

[0099] Performance test:

[0100] Detect the flexural strength, elastic modulus, maximum failure load, and Vicat softening temperature of the composite boards prepared in Examples 2 - 4 and Comparative Examples 1 - 2. The specific test results are shown in the following table:

[0101]

[0102] Analysis is carried out by combining the detection data in the above table. The flexural strength, elastic modulus, maximum failure load, and Vicat softening temperature of Examples 2-4 are all higher than those of Comparative Examples 1-2. This is because after the glass fiber and silica are modified, a modified reinforcing agent is obtained by coating a layer of polydopamine on the outside of the glass fiber and silica. The modified reinforcing agent includes that while the glass fiber and silica enhance the glass fiber and silica, multiple amino groups are grafted on the modified reinforcing agent. After the modified reinforcing agent is mixed with the modified crosslinking agent, the isocyanate group on the modified crosslinking agent and the amino group are polyadded together, so that the modified reinforcing agents on the prepared high-strength heat-resistant layer are bonded together through the modified crosslinking agent, thereby forming a dense spatial network structure. Dimethyl sulfoxide in the modified crosslinking agent can increase the distance between polymer molecules during the polymerization process and can more easily form polymers with large molecular weights during the synthesis process, so that a more dense spatial network structure is formed during the curing process, improving the flexural strength, elastic modulus, and maximum failure load of the composite board. The benzene ring and melamine on the modified crosslinking agent both have good heat-resistant properties. The nitrogen element content in melamine is relatively high. When heated, a network polymer is generated through decomposition, greatly increasing the char yield of the high-molecular polymer and affecting its melting behavior, thereby effectively improving the heat-resistant performance of the modified crosslinking agent. Moreover, magnesium oxide, magnesium chloride, gypsum powder, and the modified reinforcing agent are all flame-retardant or non-combustible materials, thus effectively improving the heat-resistant performance of the high-strength heat-resistant layer. The composite board is composed of multiple high-strength heat-resistant layers adhered by an adhesive. The adhesive is made by concentrating the modified crosslinking agent. The solvent content in the adhesive is low and it can solidify quickly. The isocyanate group on the adhesive and the amino group on the surface of the high-strength heat-resistant layer are combined through a urea group, stably bonding two adjacent high-strength heat-resistant layers together. Both the adhesive and the modified crosslinking agent have good heat-resistant properties, so that the adhesive will not denature under high-temperature conditions, making the composite board a stable whole and improving the flexural strength, elastic modulus, maximum failure load, and Vicat softening temperature of the composite board.

[0103] The above content is only an example and illustration of the structure of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the structure of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

[0104] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0105] 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 implementation manners. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the relevant 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 high-strength composite board for construction, comprising a composite board main body, characterized in that, The composite board body includes an upper high-strength heat-resistant layer (101), a middle high-strength heat-resistant layer (102), and a lower high-strength heat-resistant layer (103) arranged in sequence from top to bottom. The upper high-strength heat-resistant layer (101), the middle high-strength heat-resistant layer (102), and the lower high-strength heat-resistant layer (103) are adhered to each other pairwise by an adhesive. The upper high-strength heat-resistant layer (101), the middle high-strength heat-resistant layer (102), and the lower high-strength heat-resistant layer (103) are all composed of magnesium oxide, magnesium chloride, gypsum powder, a modified reinforcing agent, a plasticizer, and a modified crosslinking agent in a weight ratio of 20-30:15-20:10-15:4-8:0.4-0.6:8-12. Among them, the plasticizer is tris(2-ethylhexyl) phosphate; The modified crosslinking agent is obtained by polymerizing the hydroxyl group on 1-phenyl-1,2-butanediol and the isocyanate group of isophorone diisocyanate under catalyst conditions to generate a product with isocyanate groups at both ends, followed by a chain extension reaction with 4,4'-diamino-3,3'-dichlorodiphenylmethane to increase the molecular chain of the product, and then grafting with the amino group on melamine. The adhesive is obtained by subjecting the modified crosslinking agent to vacuum concentration to remove dimethyl sulfoxide; The modified reinforcing agent is obtained by the following steps: B1. Weigh 2-4 parts by weight of glass fiber and 2-4 parts by weight of silicon dioxide powder. Place the glass fiber and the silicon dioxide powder into a muffle furnace and heat at 550-600 °C for 1-2 h. Naturally cool to room temperature, and wash them with deionized water to obtain the washed glass fiber and the washed silicon dioxide; B2. Add dopamine and deionized water to a beaker and stir to dissolve, preparing a mixed solution with a concentration of 30-50 g / L. Dropwise add tris(hydroxymethyl)aminomethane hydrochloride to the mixed solution to adjust the pH of the system to 8.5-9 to obtain a dopamine aqueous solution; B3. Weigh 40-60 parts by weight of the dopamine aqueous solution, the washed glass fiber, and the washed silicon dioxide, add them to a beaker and stir, and react at room temperature for 24-26 h. After post-treatment, the modified reinforcing agent is obtained.

2. The high-strength composite board for construction according to claim 1, wherein On one side of the upper high-strength heat-resistant layer (101) and the lower high-strength heat-resistant layer (103) close to the middle high-strength heat-resistant layer (102), a plurality of protrusions (106) in a net-like structure are fixedly connected. On both sides of the middle high-strength heat-resistant layer (102), grooves (105) matching the protrusions (106) are provided, and a plurality of holes (104) are provided on the middle high-strength heat-resistant layer (102). Sound-absorbing cotton is filled in the plurality of holes (104).

3. A high-strength composite board for construction according to claim 1, characterized in that, The post-treatment operation in the B3 step is as follows: After the reaction is completed, filter. The filter cake is rinsed with deionized water and then drained. The filter cake is placed in a drying oven at a temperature of 60-70 °C and dried for 10-12 h to obtain the modified reinforcing agent.

4. The preparation method of a high-strength composite board for construction according to any one of claims 1-3, characterized in that, It includes the following operation steps: S1. Weigh 20-30 parts by weight of magnesium oxide, 15-20 parts by weight of magnesium chloride, 10-15 parts by weight of gypsum powder, 4-8 parts by weight of the modified reinforcing agent, 0.4-0.6 parts by weight of tris(2-ethylhexyl) phosphate, and 8-12 parts by weight of the modified crosslinking agent, add them to a beaker and stir for 60-80 min to obtain a mixture; S2. Add the mixture into a prefabricated mold, raise the temperature of the mold to 80 - 100 °C, keep it warm and hot-press for 30 - 50 min to form a high-strength heat-resistant layer. S3. Take three high-strength heat-resistant layers, evenly coat an adhesive between two adjacent high-strength heat-resistant layers, and bond the three high-strength heat-resistant layers together to obtain a composite board.

5. The preparation method of a high-strength composite board for construction according to claim 4, characterized in that, In the S3 operation step, a plurality of holes are provided on the high-strength heat-resistant layer located between the three high-strength heat-resistant layers, and sound-absorbing cotton is filled in the holes. After the outer walls of the three high-strength heat-resistant layers close to each other are all coated with the adhesive, they are horizontally placed in an oven at a temperature of 80 - 100 °C and pressed for 20 - 30 min, and the pressure on the top of the three high-strength heat-resistant layers is 2 - 3 MPa.

6. The preparation method of a high-strength composite board for construction according to claim 4, characterized in that, The modified cross-linking agent is prepared by the following operation steps: A1. Add 1-phenyl-1,2-butanediol and isophorone diisocyanate into a three-necked flask and stir. Under nitrogen protection, raise the temperature of the three-necked flask to 80 - 90 °C, add a catalyst into the three-necked flask, and react for 2 - 3 h to obtain intermediate I. A2. Add a 4,4'-diamino-3,3'-dichlorodiphenylmethane solution into the three-necked flask containing intermediate I and react for 2 - 3 h to obtain intermediate II. A3. Add a melamine solution into the three-necked flask containing intermediate II and react for 2 - 3 h. Pour out the reaction solution and cool it to room temperature to obtain the modified cross-linking agent.

7. The preparation method of a high-strength composite board for construction according to claim 6, characterized in that, The catalyst in step A1 is any one of dibutyltin dilaurate, stannous octoate, zinc octoate, and bismuth octoate, and the molar ratio of 1-phenyl-1,2-butanediol to isophorone diisocyanate is 1:2.1 - 2.

2.

8. The preparation method of a high-strength composite board for construction according to claim 6, characterized in that, The molar ratio of 4,4'-diamino-3,3'-dichlorodiphenylmethane to 1-phenyl-1,2-butanediol is 0.3 - 0.5:

1. The 4,4'-diamino-3,3'-dichlorodiphenylmethane solution is a mixed solution of 4,4'-diamino-3,3'-dichlorodiphenylmethane and dimethyl sulfoxide, wherein the mass concentration of 4,4'-diamino-3,3'-dichlorodiphenylmethane is 30 - 40%.

9. The preparation method of a high-strength composite board for construction according to claim 6, characterized in that, The molar ratio of melamine to 1-phenyl-1,2-butanediol is 0.2 - 0.3:

1. The melamine solution is a mixed solution of melamine and dimethyl sulfoxide, wherein the mass concentration of melamine is 40 - 50%.

10. The preparation method of a high-strength composite board for buildings according to claim 6, characterized in that, Place the modified cross-linking agent into a flask, raise the temperature of the flask to 110 - 120 °C and distill under reduced pressure until no liquid flows out to obtain the adhesive.

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