A flame retardant and heat-insulating EPE building material and its preparation method

Abstract

This application discloses a flame-retardant and heat-insulating EPE building material and its preparation method. The EPE building material includes an aluminum foil layer, a PE coating layer, and an EPE flame-retardant layer. The raw materials of the EPE flame-retardant layer include, by weight, 100 parts of low-density polyethylene (LDPE); 10-20 parts of a foaming agent; 5-10 parts of a flame retardant; 1-5 parts of an anti-drip agent; and 0.1-20 parts of at least one processing aid selected from a UV stabilizer, a nucleating agent, an anti-shrinkage agent, and a lubricant. The LDPE has a melt index of 5-10 g / 10 min at 190°C / 2.16 kg. The anti-drip agent is a core-shell anti-drip agent containing carboxyl groups on its surface. This application can improve the flame retardancy of the EPE product to V-0 while maintaining its mechanical properties.

Description

Technical Field

[0001] The present application relates to the field of EPE building materials, and in particular to a flame retardant and heat insulating EPE building material and a preparation method thereof. Background Art

[0002] EPE building materials are widely used composite building materials. Their exceptional thermal insulation, sound absorption and noise reduction, impact resistance, and environmentally friendly recyclability have demonstrated significant advantages in building envelopes, interior decoration, and other fields. These building materials typically utilize a multi-layer composite structure, the core of which is a foam layer made of EPE. This is achieved by heating and melting polyethylene resin under specific conditions, injecting a foaming agent, and then rapidly expanding and cooling, creating a large number of closed micropores. This unique microstructure gives EPE materials their lightweight, high elasticity, and excellent thermal and sound insulation properties.

[0003] However, in order to meet building fire safety standards, especially when used in high-rise buildings or special occasions, EPE building materials must have good flame retardant properties. Conventional practice is to add a certain amount of flame retardant during the EPE production process to improve the flame retardant properties of the EPE material. However, in the extrusion foaming process, due to the limited compatibility between the flame retardant particles and the polyethylene resin matrix, the flame retardant can easily agglomerate during the melt mixing stage, resulting in localized uneven concentration. This not only affects the flame retardant performance of the final product, but also has a negative impact on the foaming process, such as uneven foaming and a wide pore size distribution, thereby reducing the cell density and thermal insulation performance of the EPE material. Summary of the Invention

[0004] In order to solve the problem of uneven dispersion and foaming of flame retardants in EPE raw material systems with high flame retardant content, which leads to decreased flame retardancy and thermal insulation performance, the present application provides a flame retardant and thermal insulation EPE building material and a preparation method thereof.

[0005] In the first aspect, the present application provides a flame retardant and heat-insulating EPE building material, which includes an aluminum foil layer, a PE coating layer, and an EPE flame retardant layer. The raw materials of the EPE flame retardant layer include, by weight:

[0006] 100 parts of low-density polyethylene;

[0007] 10-20 parts of foaming agent;

[0008] 5-10 parts of flame retardant;

[0009] 1 to 5 parts of anti-dripping agent;

[0010] 0.1 to 20 parts of at least one processing aid selected from ultraviolet stabilizers, nucleating agents, anti-shrinkage agents, and lubricants;

[0011] Under the conditions of 190° C. / 2.16 kg, the melt index of the low-density polyethylene is 5 to 10 g / 10 min; and the anti-dripping agent is a core-shell anti-dripping agent having carboxyl groups on its surface.

[0012] To address the difficulty dispersing high-dosage flame retardants, this application improves melt mixing conditions by adjusting raw material properties. Specifically, a high-melt-index polyethylene resin is selected as the base material to enhance the melt fluidity of the system, allowing the flame retardant to be more fully dispersed in the molten polymer. Furthermore, improved melt fluidity results in finer and more uniform cells, resulting in a denser cell structure, which improves the flame retardancy and thermal insulation properties of the EPE material.

[0013] It should be noted that although improving melt fluidity can improve the dispersion of flame retardants and the foaming effect of materials, it will also cause EPE materials to have a molten drip phenomenon when burning, aggravating the risk of fire spread and reducing the flame retardant effect of EPE materials. In order to further solve this problem and improve the flame retardant grade of materials, this application uses a core-shell anti-dripping agent containing carboxyl groups on the surface. Its core contains polytetrafluoroethylene, and the shell material has carboxyl groups. When the EPE material burns, the core can be rapidly fibrillated to form a three-dimensional network structure, which can prevent molten plastic from dripping and effectively inhibit the formation of molten droplets, thereby improving the flame retardant effect of EPE materials. The carboxyl groups on its surface can improve the compatibility of the anti-dripping agent with the polyethylene resin substrate and promote its uniform dispersion.

[0014] Preferably, in parts by mass, the core layer raw materials of the core-shell anti-dripping agent include:

[0015] 5-10 parts of PTFE powder;

[0016] Emulsifier 0.1-1 part;

[0017] 15-30 parts of deionized water;

[0018] The shell materials of core-shell anti-dripping agent include:

[0019] 1-3 parts of styrene;

[0020] 2-5 parts of unsaturated carboxylic acid;

[0021] 1-3 parts of methyl methacrylate;

[0022] 0.05-0.1 parts of initiator.

[0023] Preferably, the emulsifier is a nonionic surfactant.

[0024] Preferably, the initiator is one or more selected from benzoyl peroxide, dicumyl peroxide, cyclohexanone peroxide, persulfate, tert-butyl hydroperoxide, and azobisisobutyronitrile.

[0025] Preferably, the core layer raw material further includes 1.5 to 2.5 parts of maleic anhydride-styrene copolymer powder.

[0026] Preferably, the D50 particle size of the maleic anhydride-styrene copolymer powder is 50 to 300 μm.

[0027] Preferably, the PTFE powder is ultrafine PTFE powder with a D50 particle size of 1 to 10 μm.

[0028] Preferably, the unsaturated carboxylic acid is selected from one or more of maleic acid, fumaric acid and itaconic acid.

[0029] Preferably, the preparation method of the core-shell anti-dripping agent comprises the following steps:

[0030] Mixing: Add maleic anhydride-styrene copolymer powder, PTFE powder and emulsifier into water to prepare PTFE dispersion;

[0031] Copolymerization: adding styrene, unsaturated carboxylic acid, methyl methacrylate and initiator to the PTFE dispersion under stirring conditions, raising the temperature to carry out copolymerization reaction, and keeping the temperature to react to obtain a copolymer emulsion;

[0032] Post-treatment: dehydrating, washing and drying the copolymer emulsion to obtain a core-shell anti-dripping agent.

[0033] Preferably, the stirring rate of the stirring condition is 800-1000 rpm.

[0034] Preferably, the copolymerization reaction temperature is 70-80°C.

[0035] Preferably, the insulation reaction time is 3 to 5 hours.

[0036] In the preparation of the anti-drip agent, this application employs a free radical copolymerization reaction, whereby the copolymerized product acts as a shell layer coated on the surface of polytetrafluoroethylene, forming particles with a core-shell structure. Unsaturated dicarboxylic acid monomers are used as the comonomer, introducing abundant carboxyl groups on the surface of the shell layer, improving the compatibility of the anti-drip agent with the substrate and facilitating its uniform dispersion.

[0037] In addition, maleic anhydride-styrene copolymer powder is added to the core layer raw material of the present application, which can fully adhere to the PTFE powder in the emulsion, promote the adhesion of the shell free radical copolymer, and form a multi-core coating structure. On the one hand, this multi-core structure is conducive to improving the compatibility of the anti-dripping agent and the shell copolymer, promoting the full coating of the shell, forming a denser coating structure, and reducing the occurrence of unexpected fiberization of the anti-dripping agent during the melt extrusion process; on the other hand, the heat resistance of the maleic anhydride-styrene copolymer can also reduce the probability of unexpected fiberization of the anti-dripping agent due to shear force or high temperature during the melt extrusion process, thereby improving the mechanical properties and flame retardant properties of the EPE material.

[0038] Preferably, the raw materials of the EPE flame retardant layer further include 3 to 6 parts of organosilicon-modified spherical fillers.

[0039] Preferably, the spherical filler is selected from one or more of spherical silica, spherical alumina and spherical titanium dioxide.

[0040] Preferably, all organosilicon-modified spherical fillers are prepared by mixing and modifying spherical fillers, aminosilane oxide and vinylsilane oxide in a mass ratio of 10:0.1-0.3:0.1-0.2.

[0041] High melt index LDPE is typically a short-chain polymer with a relatively low molecular weight and low crystallinity. Consequently, the resulting EPE product has low hardness and rigidity, hindering its impact strength. To overcome this issue, the present invention incorporates silicone-modified spherical fillers, which improve the impact strength of the resulting EPE product without affecting the fluidity of the resin substrate. Specifically, silicone-modified spherical fillers have low surface properties and flow resistance, are less likely to increase system viscosity, and thus provide excellent reinforcement.

[0042] Furthermore, the spherical filler is surface-treated with aminosilicone and vinylsilicone compounds. The vinylsilicone compound improves its compatibility with polyethylene resins, while the aminosilicone introduces amino groups that react and bond with the abundant carboxyl groups on the surface of the anti-drip agent, forming a partially cross-linked structure. This, on the one hand, enhances the mechanical strength of the EPE material and compensates for the poor mechanical properties of high-melt-index LDPE. On the other hand, the partially cross-linked structure improves the thermal stability of the anti-drip agent during melt processing and reduces unintended fiberization.

[0043] Preferably, the blowing agent is selected from butane or pentane.

[0044] Preferably, the flame retardant is selected from phosphorus-based flame retardants or organosilicon flame retardants.

[0045] Preferably, the ultraviolet stabilizer is selected from one or more of o-hydroxybenzophenone compounds, benzotriazole compounds, hindered amine compounds, and salicylate compounds.

[0046] Preferably, the anti-shrinkage agent is monoglyceride.

[0047] Preferably, the nucleating agent is selected from one or more of silicon dioxide, calcium carbonate and talc.

[0048] Preferably, the lubricant is selected from stearic acid and its derivatives, polyethylene wax or polyol ester.

[0049] In a second aspect, the present application provides a method for preparing a flame retardant and heat insulating EPE building material, which comprises the following steps:

[0050] Preparation of EPE layer: low-density polyethylene, foaming agent, flame retardant, anti-dripping agent and other raw materials are mixed evenly, added into the extrusion foaming machine, and foamed for 10 to 30 minutes at a temperature of 180 to 200°C and an inlet pressure of 8 to 12 MPa. The extruder is cooled to 90 to 100°C and the material is extruded from the die. After traction, stretching and cutting, the EPE layer is obtained.

[0051] Aluminum foil composite: The PE cast film is spread between the EPE layer and the aluminum foil layer using a laminating process, and then cooled to obtain flame-retardant and heat-insulating EPE building materials.

[0052] Preferably, the raw material of the coating layer is LDPE or a mixture of LDPE and ethylene acrylic acid copolymer and / or ethylene maleic anhydride copolymer.

[0053] More preferably, the mass ratio of LDPE to ethylene acrylic acid copolymer and / or ethylene maleic anhydride copolymer is 100:1-5.

[0054] In summary, this application has the following beneficial effects:

[0055] 1. This application uses high melt index polyethylene resin as the base material, combined with a core-shell anti-dripping agent containing carboxyl groups on the surface, which can effectively promote the formation of a dense and uniform pore structure of the material while ensuring the excellent flame retardant effect of the EPE material, thereby improving its thermal insulation performance.

[0056] 2. The present application adds maleic anhydride-styrene copolymer powder and PTFE powder to the core layer to form an anti-dripping agent with a multi-core core-shell structure. On the one hand, it can improve the dispersibility of the anti-dripping agent and improve the flame retardant properties; on the other hand, it can inhibit the anti-dripping agent from undergoing fiberization during the melt extrusion process, affecting the extrusion performance and the flame retardant and mechanical properties of the product.

[0057] 3. This application adds spherical fillers whose surfaces are modified with aminosilicone compounds and vinylsilicone compounds, which can enhance the impact strength of the product and improve the stability of the anti-drip agent while ensuring the melt fluidity and thermal insulation performance of the product, thereby reducing unexpected fiberization during the processing process. DETAILED DESCRIPTION

[0058] Preparation Example

[0059] Preparation Example 1-1, an anti-dripping agent, was prepared according to the following steps:

[0060] Mixing: Add 2 kg of maleic anhydride-styrene copolymer powder (D50 is 100 μm), 7.3 kg of PTFE powder (D50 is 3 μm, DuPont PTFE MP1200), and 0.4 kg of fatty alcohol polyoxyethylene ether into water and ultrasonically disperse for 1 hour to prepare a PTFE dispersion.

[0061] Copolymerization: Under stirring conditions of 800-1000 rpm, add 2 kg of styrene, 3.6 kg of maleic acid, 1.5 kg of methyl methacrylate and 0.08 kg of benzoyl peroxide to the PTFE dispersion, raise the temperature to 75°C for copolymerization, and keep the reaction at this temperature for 4 hours to obtain a copolymer emulsion.

[0062] Post-treatment: centrifugation, washing and drying the copolymer emulsion to obtain a core-shell anti-dripping agent.

[0063] Preparation Example 1-2, an anti-dripping agent, was prepared according to the following steps:

[0064] Mixing: Add 1.5 kg of maleic anhydride-styrene copolymer powder (D50 is 100 μm), 9.5 kg of PTFE powder (D50 is 3 μm, DuPont PTFE MP1200), and 0.6 kg of fatty alcohol polyoxyethylene ether into water and ultrasonically disperse for 1 hour to prepare a PTFE dispersion.

[0065] Copolymerization: Under stirring conditions of 800-1000 rpm, add 3 kg of styrene, 2.5 kg of maleic acid, 1 kg of methyl methacrylate and 0.065 kg of benzoyl peroxide to the PTFE dispersion, raise the temperature to 72°C for copolymerization, and keep the reaction at this temperature for 5 hours to obtain a copolymer emulsion.

[0066] Post-treatment: centrifugation, washing and drying the copolymer emulsion to obtain a core-shell anti-dripping agent.

[0067] Preparation Example 1-3, an anti-dripping agent, was prepared according to the following steps:

[0068] Mixing: Add 2.5 kg of maleic anhydride-styrene copolymer powder (D50 is 100 μm), 5.8 kg of PTFE powder (D50 is 3 μm, DuPont PTFE MP1200), and 0.3 kg of fatty alcohol polyoxyethylene ether into water and ultrasonically disperse for 1 hour to prepare a PTFE dispersion.

[0069] Copolymerization: Under stirring conditions of 800-1000 rpm, add 1 kg of styrene, 3 kg of fumaric acid, 2.5 kg of methyl methacrylate and 0.05 kg of benzoyl peroxide to the PTFE dispersion, raise the temperature to 75°C for copolymerization, and keep the reaction at this temperature for 4 hours to obtain a copolymer emulsion.

[0070] Post-treatment: centrifugation, washing and drying the copolymer emulsion to obtain a core-shell anti-dripping agent.

[0071] Preparation Example 1-4, an anti-dripping agent, differs from Preparation Example 1-1 in that, in the mixing step, an equal amount of PTFE powder is used to replace the maleic anhydride-styrene copolymer powder.

[0072] Preparation Example 1-5, an anti-dripping agent, differs from Preparation Example 1-1 in that, in the copolymerization step, maleic acid is replaced by an equal amount of acrylic acid.

[0073] Preparation Example 1-6, an anti-dripping agent, differs from Preparation Example 1-1 in that, in the copolymerization step, an equal amount of styrene is used to replace maleic acid.

[0074] Preparation Example 2-1: Organosilicon-modified spherical filler was prepared according to the following steps:

[0075] 1000 g of spherical silica (D50 particle size: 10 μm) was added to 8 L of ethanol aqueous solution (80 wt%), and dilute acid was added to adjust the pH to 5. Then, 20 g of aminopropyltriethoxysilane and 12 g of vinyltriethoxysilane were added, and the mixture was stirred for 30 min. The ethanol solvent was recovered by vacuum distillation, centrifuged, washed three times with deionized water, and then dried at 55°C.

[0076] Preparation Example 2-2: Organosilicon-modified spherical filler was prepared according to the following steps:

[0077] 1000 g of spherical silica (D50 particle size: 10 μm) was added to 8 L of ethanol aqueous solution (80 wt%), and dilute acid was added to adjust the pH to 4. Then, 15 g of aminopropyltriethoxysilane and 20 g of vinyltriethoxysilane were added, and the mixture was stirred for 30 min. The ethanol solvent was recovered by vacuum distillation, centrifuged, washed three times with deionized water, and then dried at 55°C.

[0078] Preparation Example 2-3, organosilicon-modified spherical filler, is prepared according to the following steps:

[0079] 1000 g of spherical silica (D50 particle size: 10 μm) was added to 8 L of ethanol aqueous solution (80 wt%), and dilute acid was added to adjust the pH to 4. Then, 25 g of aminopropyltriethoxysilane and 10 g of vinyltriethoxysilane were added, and the mixture was stirred for 30 min. The ethanol solvent was recovered by vacuum distillation, centrifuged, washed three times with deionized water, and then dried at 55°C.

[0080] Preparation Example 2-4, a silicone-modified spherical filler, differs from Preparation Example 2-1 in that an equal amount of aminopropyltriethoxysilane is used to replace vinyltriethoxysilane during the preparation process.

[0081] Preparation Example 2-5, a silicone-modified spherical filler, differs from Preparation Example 2-1 in that an equal amount of vinyltriethoxysilane is used to replace aminopropyltriethoxysilane during the preparation process.

[0082] Example

[0083] Example 1

[0084] Flame retardant and heat-insulating EPE building materials are prepared according to the following steps:

[0085] Preparation of EPE layer: Weigh 10kg of low-density polyethylene (melt index is 6.9g / 10min under 190℃ / 2.16kg conditions), 1.3kg of butane, 2kg of monoglyceride, 0.05kg of nucleating agent, 0.83kg of silicone flame retardant FR3028, 0.4kg of anti-dripping agent obtained in Preparation Example 1-1, and 0.5kg of silicone modified filler obtained in Preparation Example 2-1, mix them evenly, add them to the extrusion foaming machine, and foam them for 20min at a temperature of 190±5℃ and an inlet pressure of 10MPa. Then, cool the extruder to 95-100℃ and extrude the material from the die. After extrusion, pull it at a speed of 6m / min and cut it to obtain an EPE layer with a thickness of 5mm.

[0086] Aluminum foil composite: LDPE (grade 1C7A) and ethylene acrylic acid copolymer (DuPont 30705) with a mass ratio of 100:3 are added to the casting machine, and the PE film is cast between the EPE layer and the aluminum foil layer at 330±5℃, and cooled to obtain flame-retardant and heat-insulating EPE building materials.

[0087] Example 2

[0088] Flame retardant and heat-insulating EPE building materials are prepared according to the following steps:

[0089] Preparation of EPE layer: Weigh 10kg of low-density polyethylene (melt index is 8g / 10min under 190℃ / 2.16kg conditions), 0.8kg of butane, 0.3kg of monoglyceride, 0.08kg of nucleating agent, 0.9kg of silicone flame retardant FR3028, 0.15kg of the anti-dripping agent obtained in Preparation Example 1-2, and 0.6kg of the silicone modified filler obtained in Preparation Example 2-2, mix them evenly, add them to the extrusion foaming machine, and foam them for 20min at a temperature of 190±5℃ and an inlet pressure of 10MPa. Then, cool the extruder to 95-100℃ and extrude the material from the die. After extrusion, pull it at a speed of 6m / min and cut it to obtain an EPE layer with a thickness of 5mm.

[0090] Aluminum foil composite: LDPE (brand 1C7A) and ethylene acrylic acid copolymer (DuPont 30705) with a mass ratio of 100:1.5 are added to the casting machine, and the PE film is cast between the EPE layer and the aluminum foil layer at 330±5℃. The flame-retardant and heat-insulating EPE building materials are obtained by cooling.

[0091] Example 3

[0092] Flame retardant and heat-insulating EPE building materials are prepared according to the following steps:

[0093] Preparation of EPE layer: Weigh 10kg of low-density polyethylene (melt index is 6g / 10min under 190℃ / 2.16kg conditions), 1.8kg of butane, 0.2kg of monoglyceride, 0.1kg of nucleating agent, 0.55kg of silicone flame retardant FR3028, 0.5kg of anti-dripping agent obtained in Preparation Example 1-3, and 0.3kg of silicone modified filler obtained in Preparation Example 2-3, mix them evenly, add them to the extrusion foaming machine, and foam them for 10 minutes at a temperature of 190±5℃ and an inlet pressure of 12MPa. Then, cool the extruder to 95-100℃ and extrude the material from the die. After extrusion, pull it at a speed of 10m / min and cut it to obtain an EPE layer with a thickness of 5mm.

[0094] Aluminum foil composite: LDPE (brand 1C7A) and ethylene acrylic acid copolymer (DuPont 30705) with a mass ratio of 100:5 are added to the casting machine, and the PE film is cast between the EPE layer and the aluminum foil layer at 330±5℃, and cooled to obtain flame-retardant and heat-insulating EPE building materials.

[0095] Example 4

[0096] The flame-retardant and heat-insulating EPE building material is different from Example 1 in that, in the raw materials for preparing the EPE layer, the anti-dripping agent obtained in Preparation Example 1-1 is replaced by an equal amount of the anti-dripping agent obtained in Preparation Example 1-4.

[0097] Example 5

[0098] The flame-retardant and heat-insulating EPE building material is different from Example 1 in that, in the raw materials for preparing the EPE layer, the anti-dripping agent obtained in Preparation Example 1-1 is replaced by an equal amount of the anti-dripping agent obtained in Preparation Example 1-5.

[0099] Example 6

[0100] The flame-retardant and heat-insulating EPE building material is different from Example 1 in that, in the raw materials for preparing the EPE layer, the organosilicon-modified spherical filler obtained in Preparation Example 2-4 is used in place of the organosilicon-modified spherical filler obtained in Preparation Example 2-1.

[0101] Example 7

[0102] The flame-retardant and heat-insulating EPE building material is different from Example 1 in that, in the raw materials for preparing the EPE layer, the organosilicon-modified spherical filler obtained in Preparation Example 2-1 is replaced by an equal amount of the organosilicon-modified spherical filler obtained in Preparation Example 2-5.

[0103] Example 8

[0104] The flame retardant and heat insulating EPE building material is different from Example 1 in that no organosilicon-modified spherical filler is added to the raw materials for preparing the EPE layer.

[0105] Comparative Example

[0106] Comparative Example 1

[0107] The flame-retardant and heat-insulating EPE building material is different from Example 8 in that, in the raw materials for preparing the EPE layer, the anti-dripping agent obtained in Preparation Example 1-1 is replaced by an equal amount of the anti-dripping agent obtained in Preparation Example 1-6.

[0108] Comparative Example 2

[0109] The flame-retardant and heat-insulating EPE building material is different from Example 8 in that the anti-dripping agent obtained in Preparation Example 1-1 is replaced by a commercially available anti-dripping agent (Shenghua MP-850) in the raw materials for preparing the EPE layer.

[0110] Comparative Example 3

[0111] The flame retardant and heat insulating EPE building material is different from Example 8 in that the low-density polyethylene used in the raw material for preparing the EPE layer has a melt index of 2 g / 10 min (190° C. / 2.16 kg).

[0112] Comparative Example 4

[0113] The flame retardant and heat insulating EPE building material is different from Example 8 in that the low-density polyethylene used in the raw material for preparing the EPE layer has a melt index of 12 g / 10 min (190° C. / 2.16 kg).

[0114] Performance testing

[0115] Test 1: Flame retardant performance test

[0116] The flame retardant grade of the EPE layer sample is determined in accordance with the vertical method in GB / T 2408-2021 "Determination of combustion performance of plastics - Horizontal and vertical methods".

[0117] Test 2: Thermal insulation performance test

[0118] Test method: The test was carried out according to the double-plate measurement method in GB / T 10294-2008. The EPE building material sample with a specification of 150mm×150mm×5mm was fixed on the test plate. The thermal conductivity was measured using the MHY-19714 thermal conductivity tester. The average value of 10 measurements was taken as the measurement result. The test results are shown in Table 1.

[0119] Test 3: Mechanical properties test

[0120] The tensile strength and elongation at break of the specimens were tested in accordance with ISO 527-1 / 2:2019. The specimen size was 50 mm × 50 mm × 5 mm.

[0121] Test 4: Impact strength test

[0122] The notched Izod impact strength of the specimens was tested in accordance with ISO 180:2019.

[0123] Table 1. Test results

[0124]

[0125] Analysis of test results:

[0126] First of all, it should be noted that in the above test, the flame retardancy represented by V-0, V-1, and V-2 decreases in sequence; the higher the thermal conductivity coefficient, the worse the thermal insulation performance.

[0127] (1) It can be seen from Examples 1 to 8 and Comparative Examples 1 to 4 in combination with Table 1 that the EPE material of the present application, while using low-density polyethylene with a melt index of 5 to 10 g / 10 min, adds sufficient flame retardants and core-shell anti-dripping agents containing carboxyl groups on the surface, which effectively improves the flame retardant properties and thermal insulation properties of the material. The reason may be that for the flame retardant properties of EPE materials, it is important to add sufficient flame retardants, but it is also necessary to ensure that the flame retardant is fully dispersed to exert its flame retardant properties. The present application uses LDPE resin with high melt fluidity to effectively promote the uniform dispersion of flame retardants and foaming foam, improve the flame retardant effect and the uniform density of the pore structure. Furthermore, the use of an anti-dripping agent containing carboxyl groups on the surface can effectively compensate for the dripping effect caused by the increased fluidity of the resin substrate, thereby ensuring the flame retardant properties of the material.

[0128] (2) It can be seen from Example 1 and Example 4 and Table 1 that the addition of maleic anhydride-styrene copolymer powder to the anti-dripping agent core layer is beneficial to improving the flame retardant properties and mechanical properties of the EPE material. The reason may be that the addition of maleic anhydride-styrene copolymer powder can, on the one hand, reduce the probability of unexpected fiberization of the anti-dripping agent during the melt extrusion process through its own thermal stability, and reduce the damage of polytetrafluoroethylene fiberization to the mechanical and flame retardant properties of the material. Secondly, maleic anhydride-styrene copolymer powder can form a multi-core core-shell structure with polytetrafluoroethylene, which is beneficial to promote the coating of the copolymer product and obtain a denser shell layer, thereby reducing unexpected fiberization and ensuring the flame retardant properties and mechanical properties of the EPE material.

[0129] (3) Combining Example 1 with Examples 6 to 8 and Table 1, it can be seen that the mechanical properties, especially the impact strength, of the EPE material prepared using high melt index LDPE are poor, while the addition of organosilicon-modified spherical fillers can effectively improve its mechanical properties. The reason for this may be that high melt index LDPE is a short-chain polymer, and the EPE material prepared therefrom has low crystallinity, poor hardness and rigidity, which is not conducive to improving the impact strength of the product. The addition of organosilicon-modified spherical fillers can not only utilize the rigidity of the filler itself to enhance the toughening effect, but also utilize its surface amino groups to react and bond with the abundant carboxyl groups on the surface of the anti-dripping agent to form a local cross-linked structure, thereby improving the mechanical properties and the stability of the anti-dripping agent, and thus helping to improve the flame retardant properties.

[0130] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A flame retardant and heat insulating EPE building material, characterized in that: It includes an aluminum foil layer, a PE coating layer, and an EPE flame retardant layer. The raw materials of the EPE flame retardant layer include, by weight: 100 parts of low-density polyethylene; 10-20 parts of foaming agent; 5-10 parts of flame retardant; 1 to 5 parts of anti-dripping agent; 3-6 parts of organosilicon modified spherical filler; 0.1 to 20 parts of at least one processing aid selected from a UV stabilizer, a nucleating agent, an anti-shrinkage agent, and a lubricant; the melt index of the low-density polyethylene is 5 to 10 g / 10 min at 190°C / 2.16 kg; The anti-dripping agent is a core-shell type anti-dripping agent containing carboxyl groups on the surface. In parts by mass, the core layer raw materials of the core-shell type anti-dripping agent include: 5 to 10 parts of PTFE powder, 1.5 to 2.5 parts of maleic anhydride-styrene copolymer powder, 0.1 to 1 part of emulsifier, and 15 to 30 parts of deionized water; the shell layer raw materials of the core-shell type anti-dripping agent include: 1 to 3 parts of styrene, 2 to 5 parts of unsaturated carboxylic acid, 1 to 3 parts of methyl methacrylate, and 0.05 to 0.1 part of initiator; all silicone-modified spherical fillers are prepared by mixing and modifying spherical fillers, aminosilane oxide, and vinylsilane oxide in a mass ratio of 10:0.1 to 0.3:0.1 to 0.

2.

2. The flame retardant and heat insulating EPE building material according to claim 1, characterized in that: The unsaturated carboxylic acid is selected from one or more of maleic acid, fumaric acid and itaconic acid.

3. The flame retardant and heat insulating EPE building material according to claim 1, characterized in that: The preparation method of the core-shell anti-dripping agent comprises the following steps: Mixing: Add maleic anhydride-styrene copolymer powder, PTFE powder and emulsifier into water to prepare PTFE dispersion; Copolymerization: adding styrene, unsaturated carboxylic acid, methyl methacrylate and initiator to the PTFE dispersion under stirring conditions, raising the temperature to carry out copolymerization reaction, and keeping the temperature to react to obtain a copolymer emulsion; Post-treatment: dehydrating, washing and drying the copolymer emulsion to obtain a core-shell anti-dripping agent.

4. The flame retardant and heat insulating EPE building material according to claim 1, characterized in that: The blowing agent is selected from butane or pentane.

5. The flame retardant and heat insulating EPE building material according to claim 1, characterized in that: The flame retardant is selected from phosphorus flame retardants or organosilicon flame retardants.

6. A method for preparing a flame retardant and heat insulating EPE building material, characterized in that: The steps include: Preparation of EPE layer: According to the raw material ratio of the EPE building material according to any one of claims 1 to 5, low-density polyethylene, foaming agent, flame retardant, anti-dripping agent and other raw materials are uniformly mixed, added to an extrusion foaming machine, and foamed for 10 to 20 minutes at a temperature of 180 to 200°C and an inlet pressure of 8 to 12 MPa. The extruder is cooled to 95 to 100°C, and the material is extruded from the die, and the EPE layer is obtained after traction, stretching, and cutting. Aluminum foil composite: The PE cast film is spread between the EPE layer and the aluminum foil layer using a laminating process, and then cooled to obtain flame-retardant and heat-insulating EPE building materials.

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