Refractory polystyrene board as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of building materials, and particularly discloses a fire-resistant polystyrene board as well as a preparation method and application thereof. The fire-resistant polystyrene board provided by the invention comprises the following components: expandable polystyrene, thermosetting resin, a curing agent, rubber modified diatomite and a coating material, the coating material is prepared from a DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) derivative compound, rubber modified diatomite and nitrogen-doped graphene; the DOPO derivative compound comprises a phosphorus flame retardant with a double-DOPO structure and guanidine carbonate in a mass ratio of (1.5: 1)-(2.2: 1). The polystyrene board provided by the invention has the advantages of lower heat conductivity coefficient and excellent fire resistance under the condition of meeting the requirements of mechanical properties, and can reach the fire-resistant grade-A standard. The preparation method of the fire-resistant polystyrene board provided by the invention is simple in process, relatively low in raw material cost and convenient for industrial production, and can be applied to the fields of preparation of roofs or building walls and the like.

Description

Technical Field

[0001] The invention belongs to the field of building materials, and in particular relates to a fire-resistant polystyrene board and a preparation method and application thereof. Background Art

[0002] Polystyrene (PS) has the advantages of good thermal insulation, low cost, wear resistance and corrosion resistance, so it is widely used in roof insulation, building walls and other fields. However, since the molecular structure of PS is composed of flammable hydrocarbon segments and benzene ring side groups, the main chain of the molecule is very easy to decompose and burn under heat. When encountering a fire source or heat source, it will quickly melt, shrink, or even burn, and the fire will spread quickly, drip seriously, and release a large amount of heat and toxic smoke, which has a serious fire hazard, limiting the application of polystyrene materials in many industrial fields. In the prior art, the flame retardant properties of polystyrene materials are mainly improved by adding inorganic flame retardants or organic flame retardants. However, since the compatibility of inorganic flame retardants needs to be strengthened, the addition of inorganic flame retardants often has an adverse effect on the mechanical properties of polystyrene boards. Although the addition of organic flame retardants can improve the flame retardancy of polystyrene boards, as the organic flame retardants volatilize, their flame retardant properties also decrease. After testing, their flame retardant properties can only reach Class B. Therefore, it is of great significance to develop a method to improve the fire resistance level of polystyrene board while taking into account the mechanical properties. Summary of the invention

[0003] The purpose of the present invention is to provide a fire-resistant polystyrene board which can achieve Class A fire resistance while meeting the requirements of mechanical performance indicators. In addition, the present invention also provides a preparation method and application of the fire-resistant polystyrene board.

[0004] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: In a first aspect, the present invention provides a fire-resistant polystyrene board, which comprises the following components in parts by weight: 100 parts of expandable polystyrene, 50 parts to 62 parts of thermosetting resin, 5 parts to 18 parts of curing agent and 20 parts to 30 parts of coating material; The coating material includes a DOPO derivative compound, rubber-modified diatomaceous earth and nitrogen-doped graphene; The DOPO derivative compound is composed of a phosphorus-based flame retardant with a double DOPO structure and guanidine carbonate in a mass ratio of 1.5:1 to 2.2:1.

[0005] The present invention provides a polystyrene board which meets the requirements of mechanical performance indicators and has excellent fire resistance by compounding a DOPO derivative compound prepared by a phosphorus-based flame retardant with a double DOPO structure and guanidine carbonate in a specific ratio with rubber-modified diatomaceous earth and nitrogen-doped graphene.

[0006] 9,10-Dihydro-9-oxa-10-phenanthrene-10-oxide (DOPO) has the characteristics of low smoke, low toxicity and good compatibility with polymer matrix, but DOPO mainly acts as a gas phase flame retardant and cannot inhibit the generation of molten droplets when polystyrene burns. The PH bond of DOPO is very active and can react with a variety of electron-deficient compounds. Therefore, the present invention selects DOPO derivatives, that is, phosphorus-based flame retardants with double DOPO structures, for compounding with other flame retardants. Guanidine carbonate absorbs a large amount of heat when thermally decomposed, thereby reducing the temperature of the polymer surface, reducing heat transfer, and delaying the combustion. At the same time, the non-combustible gases such as carbon dioxide and ammonia produced by decomposition can dilute the concentration of oxygen in the air and the combustible gas produced by the thermal decomposition of the polymer, making it difficult for the combustion reaction to continue. In addition, during the combustion process, the nitrogen-containing substances produced by the decomposition of guanidine carbonate can promote the formation of a carbon layer on the polymer surface; and the carbon layer has good heat insulation and oxygen isolation effects, which can prevent heat and oxygen from transferring to the inside of the polymer and inhibit the further spread of combustion.

[0007] The present invention compounds a phosphorus flame retardant with a double DOPO structure with guanidine carbonate to have a synergistic effect in flame retardancy. During the combustion process, guanidine carbonate decomposes under heat to release non-combustible gases such as ammonia and carbon dioxide. When compounded with the phosphorus flame retardant with a double DOPO structure, the phosphorus flame retardant promotes the formation of a carbon layer on the polymer surface by forming substances such as phosphate esters, mainly playing a role in the condensed phase, and the gas released by guanidine carbonate can not only interfere with the gas phase reaction during the combustion process, but also promote the formation of a more stable, heat-insulating, oxygen-isolating expanded carbon layer structure, thereby improving the flame retardant performance.

[0008] Although diatomaceous earth has the advantages of being loose, light, porous, and rich in active silicon, it has poor compatibility with organic matter. The present invention organically modifies diatomaceous earth, which not only has better compatibility with polystyrene, but also increases the quality of the carbon layer after the matrix is ​​burned and reduces the smoke release during the matrix combustion process.

[0009] Since graphene itself has a two-dimensional sheet structure, it can act as a physical barrier in the material and prevent the transfer of heat and substances. After nitrogen doping, the sheet structure of graphene is more stable, and it can better form a barrier layer inside the material, delaying the spread of heat and the diffusion of combustible substances; at the same time, the introduction of nitrogen atoms can also increase the surface activity and chemical reactivity of graphene, making it easier to react with other substances during the combustion process to generate more carbonaceous products, further enhancing the stability and flame retardant effect of the carbon layer; in addition, at high temperatures, the nitrogen element in nitrogen-doped graphene can decompose to produce non-combustible gases, which can dilute the concentration of combustible gases in the combustion area and reduce the oxygen content, thereby inhibiting the combustion reaction. The release of gas can also play a synergistic flame retardant role between the condensed phase and the gas phase, further improving the flame retardant efficiency. In addition, nitrogen-doped graphene can synergize with phosphorus-based flame retardants, guanidine carbonate and rubber-modified diatomaceous earth with a double DOPO structure, not only enhancing the stability of the carbon layer in the condensed phase, but also playing a diluting and barrier role in the gas phase, jointly improving the flame retardant performance. In addition, in the present invention, nitrogen-doped graphene can also serve as a reinforcing phase to effectively bear and transfer loads, and can also absorb and dissipate energy through interaction with polymer molecular chains, thereby improving the strength, toughness and ductility of the polystyrene matrix material.

[0010] In summary, the present invention adds materials such as phosphorus-based flame retardants with double DOPO structures, guanidine carbonate, rubber-modified diatomaceous earth and nitrogen-doped graphene, so that the four materials synergistically exert flame retardant effects while improving the strength and toughness of the matrix. They are reasonably proportioned with expandable polystyrene, thermosetting resin and curing agent to provide a polystyrene board with excellent flame retardant properties while meeting mechanical properties. The polystyrene board can reach the fire resistance Class A standard.

[0011] Preferably, the method for preparing the phosphorus-based flame retardant having a double DOPO structure comprises the following steps: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and terephthalaldehyde are subjected to a condensation reaction at 110° C. to 115° C. to obtain the flame retardant.

[0012] The specific preparation method of the phosphorus-based flame retardant with a double DOPO structure includes the following steps: adding terephthalaldehyde, DOPO and N,N-dimethylformamide to a round-bottom flask equipped with a reflux condenser, a thermometer and a stirrer, then introducing nitrogen, heating to 110°C~115°C and maintaining the temperature with stirring for 6h~7h, and removing N,N-dimethylformamide by reduced pressure distillation after cooling, washing with 95% ethanol for 3 times, and then washing with water for 2 times, and vacuum drying at 60°C to constant weight to obtain a white powder, which is the phosphorus-based flame retardant with a double DOPO structure, and its structural formula is shown below.

[0013] .

[0014] Preferably, the rubber-modified diatomaceous earth comprises acrylate rubber-modified diatomaceous earth.

[0015] Preferably, the preparation method of the acrylate rubber modified diatomaceous earth comprises the following steps: adding diatomaceous earth and acrylate rubber into a mixer, mixing at a rotation speed of 25000 rpm to 30000 rpm, and uniformly dispersing the liquid acrylate rubber and coating the diatomaceous earth surface by high-speed shearing to obtain acrylate rubber modified diatomaceous earth.

[0016] Preferably, the acrylic rubber is in liquid state; The mass ratio of diatomaceous earth to acrylic rubber is 8:2-9:1; The mixing time is 1.5 min to 2 min.

[0017] Preferably, the nitrogen content of the nitrogen-doped graphene is 5wt%~10wt% and the thickness is 1nm~3nm.

[0018] Preferably, the mass ratio of the DOPO derivative compound, rubber-modified diatomaceous earth and nitrogen-doped graphene is 40:40-50:5-10.

[0019] Preferably, the thermosetting resin comprises at least one of a phenolic resin or an epoxy resin; The curing agent includes at least one of sulfuric acid, phosphoric acid, p-toluenesulfonic acid or phthalic anhydride.

[0020] In a second aspect, the present invention provides a method for preparing the above-mentioned fire-resistant polystyrene board, the preparation method comprising the following steps: Step 1, pre-foaming the expandable polystyrene to obtain pre-foamed polystyrene particles; Step 2: adding the thermosetting resin and the curing agent into the pre-expanded polystyrene particles and mixing them evenly, adding the coating material, and performing compression molding to obtain the fire-resistant polystyrene board.

[0021] The preparation method provided by the present invention has the advantages of simple preparation process, relatively small amount of coating material used, relatively low production cost and convenience for industrial production.

[0022] In a third aspect, the present invention further provides use of the fire-resistant polystyrene board provided in the first aspect or the fire-resistant polystyrene board prepared in the second aspect in a building wall.

[0023] Since the fire-resistant polystyrene board provided by the present invention has mechanical properties that meet the requirements and has excellent flame retardant properties, it can be further applied to fields such as roofs or building walls. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] Example 1 This embodiment provides a fire-resistant polystyrene board, which includes the following components in parts by weight: 100 parts of expandable polystyrene, 50 parts of 2123 phenolic resin, 5 parts of p-toluenesulfonic acid, and 20 parts of coating material; The coating material is prepared by compounding a DOPO derivative compound, acrylate rubber modified diatomaceous earth and nitrogen-doped graphene in a mass ratio of 40:40:5; The DOPO derivative compound is composed of a phosphorus-based flame retardant with a double DOPO structure and guanidine carbonate in a mass ratio of 1.5:1.

[0026] The preparation methods of the double DOPO structure phosphorus-based flame retardant and acrylic rubber modified diatomaceous earth are as follows.

[0027] (1) The preparation method of the double DOPO structure phosphorus flame retardant comprises the following steps: In a round-bottom flask equipped with a reflux condenser, a thermometer and a stirrer, 16.1 g (0.12 mol) of terephthalaldehyde, 43.2 g (0.2 mol) of DOPO and 300 mL of N,N-dimethylformamide were added, and then nitrogen was introduced. The temperature was raised to 115°C and maintained at this temperature for 6 hours. After cooling, N,N-dimethylformamide was removed by distillation under reduced pressure, and the mixture was washed 3 times with 95% ethanol and 2 times with water. The mixture was vacuum dried at 60°C to constant weight to obtain a white powder, which is 45.3 g of the phosphorus-based flame retardant with a dual DOPO structure, and its structural formula is shown below.

[0028] .

[0029] (2) The preparation method of acrylic rubber modified diatomaceous earth comprises the following steps: Diatomaceous earth and liquid acrylic rubber were added into a high-speed mixer at a mass ratio of 8:2, and mixed at a rotation speed of 30000 rpm for 1.5 minutes. The liquid acrylic rubber was evenly dispersed and coated on the surface of the diatomaceous earth by high-speed shearing to obtain acrylic rubber modified diatomaceous earth.

[0030] In this embodiment, the nitrogen-doped graphene selected was purchased from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, with a purity of >98%, a nitrogen content of 5wt%~0wt%, a thickness of 1nm~3nm, a size of 2μm~10μm, and a specific surface area of ​​100m 2 / g~300m 2 / g.

[0031] This embodiment also provides a method for preparing the above-mentioned fire-resistant polystyrene board, and the preparation method comprises the following steps: Step 1: Steam pre-foam and ripen the expandable polystyrene to obtain a density of 20kg / m 3³ Pre-expanded polystyrene pellets; Step 2: Add 2123 phenolic resin and p-toluenesulfonic acid to the pre-expanded polystyrene particles and mix them evenly, then add the coating material after mixing at 85° C. for 60 minutes, dry at 60° C., and perform compression molding to obtain the fire-resistant polystyrene board.

[0032] Example 2 This embodiment provides a fire-resistant polystyrene board, which includes the following components in parts by weight: 100 parts of expandable polystyrene, 62 parts of E-44 epoxy resin, 18 parts of phthalic anhydride, and 30 parts of coating material; The coating material is prepared by compounding a DOPO derivative compound, acrylate rubber modified diatomaceous earth and nitrogen-doped graphene in a mass ratio of 40:50:10; The DOPO derivative compound is composed of a phosphorus-based flame retardant with a double DOPO structure and guanidine carbonate in a mass ratio of 2.2:1.

[0033] Among them, the nitrogen-doped graphene selected in this embodiment is the same as that in Example 1, and the preparation method of the phosphorus-based flame retardant with a double DOPO structure and the preparation method of the acrylic rubber-modified diatomaceous earth are specifically as follows: (1) The preparation method of the double DOPO structure phosphorus flame retardant comprises the following steps: In a round-bottom flask equipped with a reflux condenser, a thermometer and a stirrer, 13.4 g (0.10 mol) of terephthalaldehyde, 43.2 g (0.2 mol) of DOPO and 300 mL of N,N-dimethylformamide were added, and then nitrogen was introduced. The temperature was raised to 110°C and maintained at this temperature for 7 hours. After cooling, N,N-dimethylformamide was removed by vacuum distillation. The mixture was washed 3 times with 95% ethanol and 2 times with water. The mixture was vacuum dried at 60°C to constant weight to obtain a white powder, which is 44.2 g of the phosphorus-based flame retardant with a dual DOPO structure. Its structural formula is shown below.

[0034] .

[0035] (2) The preparation method of acrylic rubber modified diatomaceous earth is as follows: Diatomaceous earth and liquid acrylic rubber were added into a high-speed mixer at a mass ratio of 9:1, and mixed at a rotation speed of 25000 rpm for 1.5 minutes. The liquid acrylic rubber was evenly dispersed and coated on the surface of the diatomaceous earth by high-speed shearing to obtain acrylic rubber modified diatomaceous earth.

[0036] This embodiment also provides a method for preparing the above-mentioned fire-resistant polystyrene board, and the preparation method comprises the following steps: Step 1: Steam pre-foam and ripen the expandable polystyrene to obtain a density of 18kg / m 3 Pre-expanded polystyrene pellets; Step 2: Add E-44 epoxy resin and phthalic anhydride to the pre-expanded polystyrene particles and mix them evenly, then add the coating material after mixing at 90° C. for 30 minutes, dry at 60° C., and perform compression molding to obtain the fire-resistant polystyrene board.

[0037] Example 3 This embodiment provides a fire-resistant polystyrene board, which includes the following components in parts by weight: 100 parts of expandable polystyrene, 28 parts of E-44 epoxy resin, 28 parts of 2027 phenolic resin, 15 parts of phthalic anhydride, and 25 parts of coating material; The coating material is prepared by compounding a DOPO derivative compound, acrylate rubber modified diatomaceous earth and nitrogen-doped graphene in a mass ratio of 40:45:8; The DOPO derivative compound is composed of a phosphorus-based flame retardant with a double DOPO structure and guanidine carbonate in a mass ratio of 2:1.

[0038] The nitrogen-doped graphene used in this embodiment is the same as that in Example 1, the preparation method of the phosphorus-based flame retardant with a double DOPO structure is as described in Example 1, and the preparation method of the acrylic rubber-modified diatomaceous earth is as follows: Diatomaceous earth and liquid acrylic rubber were added into a high-speed mixer at a mass ratio of 85:15, and mixed at a rotation speed of 25000 rpm for 2 minutes. The liquid acrylic rubber was evenly dispersed and coated on the surface of the diatomaceous earth by high-speed shearing to obtain acrylic rubber modified diatomaceous earth.

[0039] This embodiment also provides a method for preparing the above-mentioned fire-resistant polystyrene board, and the preparation method comprises the following steps: Step 1: Pre-expand and mature the expandable polystyrene with steam to obtain a density of 22 kg / m 3 Pre-expanded polystyrene pellets; Step 2: Add E-44 epoxy resin, 2027 phenolic resin and phthalic anhydride to the pre-expanded polystyrene particles and mix them evenly, then add the coating material after mixing at 90° C. for 30 minutes, dry at 60° C., and perform compression molding to obtain the fire-resistant polystyrene board.

[0040] Comparative Example 1 Comparative Example 1 provides a refractory polystyrene board. The raw materials and preparation method of the refractory polystyrene board provided in this comparative example are basically the same as those in Example 3, with the only difference being that in terms of raw materials, the coating material selected is unmodified diatomaceous earth, and the types and amounts of other raw materials are the same as those in Example 3.

[0041] In the preparation method, the selected raw materials were replaced accordingly, and the other preparation parameters were the same as those in Example 3.

[0042] Effect Example 1 Determine the fire rating of different products according to GB8624-2019 "Classification of Combustion Performance of Building Materials and Products"; Determine the thermal conductivity of different products according to GB / T10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Guarded Hot Plate Method"; The compressive strength of different products is measured in accordance with GB / T 10801.1-2021 "Molded polystyrene foam (EPS) for thermal insulation".

[0043] The tensile strength is measured in accordance with JG / T 536-2017 "Thermosetting composite polystyrene foam insulation board".

[0044] The specific measurement results are shown in Table 1.

[0045] Table 1

[0046] It can be seen from the data in Table 1 that, compared with the coating material using conventional diatomite and adjusting the ratio of the DOPO derivative compound, diatomite and nitrogen-doped graphene, the thermal conductivity of the polystyrene board provided by the present invention is significantly reduced, the tensile strength and the compressive strength are significantly improved, and the fire resistance level is improved. The fire-resistant polystyrene board prepared in the embodiment of the present invention can reach the A-class fire resistance level while meeting the relevant mechanical property requirements, and can be applied to the fields of roofs or building walls.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fire-resistant polystyrene board, characterized in that: The invention comprises the following components in parts by weight: 100 parts of expandable polystyrene, 50 parts to 62 parts of thermosetting resin, 5 parts to 18 parts of curing agent and 20 parts to 30 parts of coating material; The coating material includes a DOPO derivative compound, rubber-modified diatomaceous earth and nitrogen-doped graphene; The DOPO derivative compound comprises a phosphorus-based flame retardant having a double DOPO structure and guanidine carbonate in a mass ratio of 1.5:1 to 2.2:

1.

2. The fire-resistant polystyrene board according to claim 1, characterized in that: The preparation method of the phosphorus-based flame retardant with a double DOPO structure comprises the following steps: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and terephthalaldehyde are subjected to a condensation reaction at 110° C. to 115° C. to obtain the flame retardant.

3. The fire-resistant polystyrene board according to claim 1, characterized in that: The rubber-modified diatomaceous earth includes acrylate rubber-modified diatomaceous earth.

4. The fire-resistant polystyrene board according to claim 3, characterized in that: The preparation method of the acrylate rubber modified diatomaceous earth comprises the following steps: adding diatomaceous earth and acrylate rubber into a mixer, mixing them at a rotation speed of 30000 rpm to 25000 rpm, and preparing the acrylate rubber modified diatomaceous earth.

5. The fire-resistant polystyrene board according to claim 4, characterized in that: The acrylic rubber is in liquid state; and / or The mass ratio of diatomaceous earth to acrylic rubber is 8:2-9:1; and / or The mixing time is 1.5 min to 2 min.

6. The fire-resistant polystyrene board according to claim 1, characterized in that: The nitrogen content in the nitrogen-doped graphene is 5wt%-10wt%.

7. The fire-resistant polystyrene board according to claim 1, characterized in that: The mass ratio of the DOPO derivative compound, rubber-modified diatomaceous earth and nitrogen-doped graphene is 40:40-50:5-10.

8. The fire-resistant polystyrene board according to claim 1, characterized in that: The thermosetting resin comprises at least one of a phenolic resin or an epoxy resin; and / or The curing agent includes at least one of sulfuric acid, phosphoric acid, p-toluenesulfonic acid or phthalic anhydride.

9. The method for preparing a fire-resistant polystyrene board according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: Step 1, pre-foaming the expandable polystyrene to obtain pre-foamed polystyrene particles; Step 2: adding the thermosetting resin and the curing agent into the pre-expanded polystyrene particles and mixing them evenly, adding the coating material, and performing compression molding to obtain the fire-resistant polystyrene board.

10. Use of the fire-resistant polystyrene board according to any one of claims 1 to 8 or the fire-resistant polystyrene board prepared according to claim 9 in roofs or building walls.

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