Preparation process and application of modified polystyrene high-strength flame-retardant thermal insulation material

Abstract

The invention discloses a preparation process and application of a modified polystyrene high-strength flame-retardant thermal insulation material. The process comprises the following steps: (1) putting fly ash floating beads into alkali liquor, continuously stirring, then putting the obtained floating beads into saturated lime water, and carrying out heat preservation under a heating condition, so as to obtain pretreated floating beads; and (2) uniformly mixing the pretreated floating beads with ethanol dissolved with a silane coupling agent, standing, and drying to remove ethanol, thereby obtaining the modified fly ash floating beads. And (3) taking a styrene monomer, an initiator, a nucleating agent, the modified fly ash floating beads and a foaming agent as raw materials. The preparation method comprises the following steps: uniformly mixing the raw materials, heating and mixing, and extruding and granulating to obtain the modified polystyrene particles. And (4) uniformly mixing the modified polystyrene particles with silica sol, and drying to obtain the high-strength flame-retardant thermal insulation material. The process provided by the invention not only effectively improves the mechanical strength and flame retardant property of the polystyrene thermal insulation material, but also reduces the adverse effect on the thermal insulation property of the polystyrene thermal insulation material.

Description

Technical Field

[0001] The invention relates to the technical field of polystyrene thermal insulation material preparation, and in particular to a preparation process and application of a modified polystyrene high-strength flame-retardant thermal insulation material. Background Art

[0002] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information has become the prior art known to ordinary technicians in the field.

[0003] Polystyrene is a thermoplastic foam material made from the polymerization of styrene monomers. It has excellent thermal insulation, sound insulation, light weight, waterproof and anti-seepage characteristics. Polystyrene is widely used to make foam boards, foam boxes, etc., and is widely used in the fields of construction, food, chemical industry, agriculture, etc. However, the strength of polystyrene materials is relatively poor, resulting in poor impact resistance and bearing capacity of products made from polystyrene. It is easy to be damaged during transportation and use, which limits the application of polystyrene materials in a wider range of fields.

[0004] In order to overcome the above problems, one of the commonly used methods is to add glass fiber, filler, etc. into the raw materials for preparing polystyrene materials. However, due to the poor compatibility and dispersibility between polystyrene materials, the effect of improving the mechanical strength of polystyrene materials is limited. In addition, the above method will also lead to a significant increase in the density of polystyrene materials and a decrease in thermal insulation performance. In addition, polystyrene materials generally have poor flame retardancy and are prone to melt and become unstable when heated, catching fire and burning, which in turn causes the fire to spread rapidly, causing greater accidents, and also emitting a large amount of black smoke and toxic and harmful gases. Summary of the invention

[0005] The present invention provides a preparation process and application of a modified polystyrene high-strength flame-retardant thermal insulation material, which not only effectively improves the mechanical properties and flame-retardant properties of the polystyrene thermal insulation material, but also reduces the adverse effects on the thermal insulation properties of the polystyrene thermal insulation material. Specifically, the technical solution of the present invention is as follows. First, the present invention discloses a preparation process of a modified polystyrene high-strength flame-retardant thermal insulation material, comprising the following steps: (1) The fly ash beads are placed in an alkaline solution and continuously stirred, and then the obtained beads are placed in saturated lime water and kept warm under heating conditions to obtain pretreated beads.

[0006] (2) The pretreated floating beads are mixed evenly with ethanol in which a silane coupling agent is dissolved, and the mixture is allowed to stand and then dried to remove the ethanol, thereby obtaining modified fly ash floating beads.

[0007] (3) Styrene monomer, initiator, nucleating agent, the modified fly ash floating beads and foaming agent are used as raw materials. The above raw materials are mixed evenly, heated and kneaded, and then extruded and granulated to obtain modified polystyrene particles.

[0008] (4) The modified polystyrene particles are mixed with silica sol and stirred evenly, and dried to obtain the modified polystyrene high-strength flame-retardant thermal insulation material.

[0009] Furthermore, in step (1), the ratio of the fly ash beads to the alkali solution is 1 g: 10-20 ml. Optionally, the concentration of the alkali solution is 0.3-0.5 mol / L.

[0010] Furthermore, in step (1), the alkaline solution includes at least one of a sodium hydroxide solution and a potassium hydroxide solution.

[0011] Furthermore, in step (1), the continuous stirring treatment time is 45-60 min, and the stirring rate is 50-80 r / min.

[0012] Furthermore, in step (1), the ratio of the floating beads to saturated lime water is 1 g: 20-40 ml.

[0013] Furthermore, in step (1), the heating temperature is 40-60° C., and the insulation time is 7-10 hours.

[0014] Furthermore, in step (2), the ratio of the pretreated floating beads to the ethanol in which the silane coupling agent is dissolved is 1 g: 1-2 ml. Optionally, the mass fraction of the silane coupling agent in the ethanol is 0.2-0.5%, and the mass fraction of the ethanol is 85-95%.

[0015] Furthermore, in step (2), the silane coupling agent includes at least one of kh550, kh560, kh570, etc.

[0016] Furthermore, in step (2), the standing time is 20-30 minutes, the drying temperature is 40-50° C., and the time is 5-10 minutes, so as to remove the ethanol solvent on the surface of the pretreated floating beads.

[0017] Furthermore, in step (3), the proportions of the raw materials are: 94-108 parts by weight of styrene monomer, 0.4-0.7 parts by weight of initiator, 1-2.3 parts by weight of nucleating agent, 8-12 parts by weight of modified fly ash floating beads, and 6-9.5 parts by weight of foaming agent.

[0018] Furthermore, in step (3), the initiator includes any one of benzoyl peroxide, dibenzoyl peroxide, diisopropylbenzene peroxide, etc.

[0019] Furthermore, in step (3), the nucleating agent includes any one of phenolic resin, polyethylene wax, etc.

[0020] Furthermore, in step (3), the foaming agent includes any one of n-pentane, isopentane, neopentane, etc.

[0021] Furthermore, in step (3), prepolymerization is first performed at 80-90°C for 0.5-1 hour, then the temperature is raised to 160-180°C for kneading for 0.5-1.5 hours, and then the temperature is lowered to 100-130°C for extrusion granulation.

[0022] Furthermore, in step (4), the silica sol is 2-3.5% of the mass of the modified polystyrene particles.

[0023] Furthermore, in step (4), the drying temperature is 50-60° C. and the drying time is 30-40 min.

[0024] Secondly, the present invention discloses the application of the modified polystyrene high-strength flame-retardant thermal insulation material obtained by the preparation process in the fields of construction, food, chemical industry, agriculture, etc.

[0025] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: The modified polystyrene high-strength flame-retardant thermal insulation material of the present invention is added with modified fly ash floating beads, which not only have good compatibility with the polystyrene thermal insulation material, improve the mechanical properties, but also improve the flame retardant properties of the polystyrene thermal insulation material. In addition, since the modified fly ash floating beads have the characteristics of being hollow, low in density and having good thermal insulation properties, after being added to the polystyrene thermal insulation material, it is equivalent to forming a plurality of closed holes therein, which can effectively reduce the transmission of heat, thereby improving the mechanical strength of the polystyrene thermal insulation material, so that the polystyrene thermal insulation material still maintains good thermal insulation properties. At the same time, the present invention first performs surface treatment on the fly ash floating beads in an alkali solution, so that the silicon oxygen bonds (Si-O-Si) and aluminum oxygen bonds (Al-O-Al) in the silicon oxygen tetrahedron and aluminum oxygen tetrahedron network structure on the surface thereof are broken, so that the fly ash floating beads form an active surface. The present invention further mixes it with the saturated lime water, and the calcium hydroxide reacts with the active surface to form hydrated calcium silicate and hydrated calcium aluminate. Then, the fly ash floating beads are further treated with a silane coupling agent, and the silicon hydroxyl groups formed after the hydrolysis of the silane coupling agent and the hydroxyl groups on the surface of the fly ash floating beads are condensed to combine the two, and finally form modified fly ash floating beads. After being added to the polystyrene thermal insulation material, on the one hand, the silane coupling agent plays a bridging role between the fly ash floating beads and the polystyrene thermal insulation material, which can effectively improve the compatibility of the two, thereby helping to improve the mechanical properties of the polystyrene thermal insulation material. On the other hand, the steric hindrance effect of the hydrated calcium silicate and hydrated calcium aluminate formed on the surface of the fly ash floating beads can also improve the dispersibility of the fly ash floating beads and improve the mechanical properties of the polystyrene thermal insulation material. On the other hand, the hydrated calcium silicate and hydrated calcium aluminate are dehydrated and release water molecules during the heating process, thereby reducing the combustion temperature and improving the flame retardant ability of the polystyrene thermal insulation material. The present invention utilizes the composition characteristics of fly ash floating beads to modify them, which not only improves the mechanical properties and flame retardant properties of polystyrene thermal insulation materials, but also enables the polystyrene thermal insulation materials to still maintain good thermal insulation properties. Finally, the silica sol loaded on the surface of the modified polystyrene particles of the present invention helps to further improve the flame retardant properties of the styrene thermal insulation materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0027] Figure 1 This is a sample picture of modified polystyrene particles prepared in the following Example 1. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, any method and material similar or equivalent to the described content can be applied to the method of the present invention. Now the technical solution of the present invention is further described in conjunction with the accompanying drawings and specific embodiments.

[0029] Example 1 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads were mixed with 0.4 mol / L sodium hydroxide solution at a ratio of 1 g:15 ml, and then stirred continuously for 60 min at a stirring rate of 30 r / min. Then the fly ash floating beads were filtered out, added to a container with saturated lime water at a ratio of 1 g:30 ml, and stirred evenly. After sealing, the mixture was heated in a water bath to 55°C for 8 hours, cooled to room temperature, and the solid product was filtered out to obtain pre-treated floating beads for later use.

[0030] (2) Mix the silane coupling agent KH550 with 90% ethanol by mass and stir evenly to obtain an ethanol solution with a silane coupling agent mass fraction of 0.4%. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g:1 ml and stir evenly, let it stand for 20 minutes, heat it to 50°C and dry it for 7 minutes to obtain the modified fly ash floating beads, which are set aside.

[0031] (3) Take the following raw materials in the following proportions: 100 parts by weight of styrene monomer, 0.45 parts by weight of benzoyl peroxide, 1.5 parts by weight of polyethylene wax, 10 parts by weight of the modified fly ash beads prepared in this example, and 8 parts by weight of n-pentane. Mix the above raw materials evenly and heat to 85°C for prepolymerization for 40 minutes, then heat to 170°C for mixing for 1 hour, then cool to 120°C and extrude and granulate to obtain modified polystyrene particles with a particle size of 1 mm, such as Figure 1 shown.

[0032] (4) Add 3% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 50° C. for 35 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0033] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board through an extruder, and then the apparent density is tested according to GB / T6343-1996 "Determination of the apparent (volume) density of foam plastics and rubber". The impact strength of the insulation board is tested according to GB / T1843-2008 "Plastic cantilever beam impact strength". The limiting oxygen index of the insulation board is tested according to GB / T2408-2008 "Determination of the combustion performance of plastics". The thermal conductivity of the insulation board is tested according to GB / T10294-2008 "Determination of steady-state thermal resistance and related properties of insulating materials - protective hot plate method", and the results are shown in the following table. In addition, a blank group without the modified fly ash floating beads was set up, and its apparent density was tested according to the above method. The results show that the apparent density of the insulation board of this embodiment only increased by 4.71% relative to the blank group. It can be seen that the influence of the modified fly ash floating beads on the density of the insulation board remains at a low level; .

[0034] Example 2 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads were mixed with 0.3 mol / L sodium hydroxide solution at a ratio of 1 g: 20 ml, and then stirred continuously for 50 min at a stirring rate of 40 r / min. Then the fly ash floating beads were filtered out, added to a container with saturated lime water at a ratio of 1 g: 20 ml, and stirred evenly. After sealing, the mixture was heated in a water bath to 40°C for 10 hours, cooled to room temperature, and the solid product was filtered out to obtain pre-treated floating beads for later use.

[0035] (2) Mix the silane coupling agent KH560 with ethanol (mass fraction 85%) and stir evenly to obtain an ethanol solution with a mass fraction of 0.5% of the silane coupling agent. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g: 2 ml and stir evenly. After standing for 30 minutes, heat to 40°C and dry for 10 minutes to obtain the modified fly ash floating beads for later use.

[0036] (3) Take the following raw materials in the following proportions: 108 parts by weight of styrene monomer, 0.7 parts by weight of dibenzoyl peroxide, 2.3 parts by weight of polyethylene wax, 12 parts by weight of the modified fly ash beads prepared in this example, and 9.5 parts by weight of isopentane. Mix the above raw materials evenly, heat to 90°C for prepolymerization for 30 minutes, then heat to 180°C for mixing for 0.5 hours, then cool to 130°C and extrude for granulation to obtain modified polystyrene particles with a particle size of 1 mm.

[0037] (4) Add 2% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 60° C. for 30 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0038] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board through an extruder, and then the insulation board is tested for apparent density, impact strength, limiting oxygen index and thermal conductivity by the same method as in the above-mentioned embodiment 1. The results are shown in the following table. In addition, a blank group without the modified fly ash floating beads was set up, and its apparent density was tested according to the above method. The results showed that the apparent density of the insulation board of this embodiment increased by only 5.76% relative to the blank group. It can be seen that the influence of the modified fly ash floating beads on the density of the insulation board is kept at a low level; .

[0039] Example 3 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads were mixed with 0.5 mol / L potassium hydroxide solution at a ratio of 1 g:15 ml, and then stirred continuously for 45 min at a stirring rate of 40 r / min. Then the fly ash floating beads were filtered out, added to a container with saturated lime water at a ratio of 1 g:40 ml, and stirred evenly. After sealing, the mixture was heated in a water bath to 60°C for 7 hours, cooled to room temperature, and the solid product was filtered out to obtain pre-treated floating beads for later use.

[0040] (2) Mix the silane coupling agent KH570 with 95% ethanol by mass and stir evenly to obtain an ethanol solution with a silane coupling agent mass fraction of 0.2%. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g:1.5 ml and stir evenly, let it stand for 20 minutes, heat it to 50°C and dry it for 5 minutes to obtain the modified fly ash floating beads, which are set aside.

[0041] (3) Take the following raw materials in the following proportions: 94 parts by weight of styrene monomer, 0.4 parts by weight of dicumyl peroxide, 1 part by weight of polyethylene wax, 8 parts by weight of the modified fly ash beads prepared in this example, and 6 parts by weight of neopentane. Mix the above raw materials evenly, heat to 80°C for prepolymerization for 60 minutes, then heat to 160°C for mixing for 1.5 hours, then cool to 100°C and extrude for granulation to obtain modified polystyrene particles with a particle size of 1 mm.

[0042] (4) Add 3.5% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 50° C. for 40 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0043] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board through an extruder, and then the insulation board is tested for apparent density, impact strength, limiting oxygen index and thermal conductivity by the same method as in the above-mentioned embodiment 1. The results are shown in the following table. In addition, a blank group without the modified fly ash floating beads was set up, and its apparent density was tested according to the above method. The results showed that the apparent density of the insulation board of this embodiment increased by only 5.03% relative to the blank group. It can be seen that the influence of the modified fly ash floating beads on the density of the insulation board is kept at a low level; .

[0044] Example 4 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Take the following raw materials in the following proportions: 100 parts by weight of styrene monomer, 0.45 parts by weight of benzoyl peroxide, 1.5 parts by weight of polyethylene wax, 10 parts by weight of fly ash beads, and 8 parts by weight of n-pentane. Mix the above raw materials evenly and heat to 85°C for prepolymerization for 40 minutes. Then heat to 170°C for mixing for 1 hour. Then cool to 120°C and extrude and granulate to obtain modified polystyrene particles with a particle size of 1 mm.

[0045] (2) Add 3% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 50° C. for 35 minutes to obtain a polystyrene high-strength flame-retardant thermal insulation material.

[0046] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board by an extruder, and then the impact strength, limiting oxygen index and thermal conductivity of the insulation board are tested by the same method as in the above embodiment 1. The results are shown in the following table; .

[0047] Example 5 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads and 0.5 mol / L potassium hydroxide solution were mixed in a ratio of 1 g:15 ml and stirred continuously for 45 min at a stirring rate of 40 r / min. The fly ash floating beads were then filtered out to obtain pre-treated floating beads for later use.

[0048] (2) Mix the silane coupling agent KH570 with 95% ethanol by mass and stir evenly to obtain an ethanol solution with a silane coupling agent mass fraction of 0.2%. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g:1.5 ml and stir evenly, let it stand for 20 minutes, heat it to 50°C and dry it for 5 minutes to obtain the modified fly ash floating beads, which are set aside.

[0049] (3) Take the following raw materials in the following proportions: 94 parts by weight of styrene monomer, 0.4 parts by weight of dicumyl peroxide, 1 part by weight of polyethylene wax, 8 parts by weight of the modified fly ash beads prepared in this example, and 6 parts by weight of neopentane. Mix the above raw materials evenly, heat to 80°C for prepolymerization for 60 minutes, then heat to 160°C for mixing for 1.5 hours, then cool to 100°C and extrude for granulation to obtain modified polystyrene particles with a particle size of 1 mm.

[0050] (4) Add 3.5% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 50° C. for 40 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0051] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board by an extruder, and then the impact strength, limiting oxygen index and thermal conductivity of the insulation board are tested by the same method as in the above embodiment 1. The results are shown in the following table; .

[0052] Example 6 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Add fly ash beads and saturated lime water in a ratio of 1g:20ml into a container and stir evenly. Seal the container and heat it in a water bath to 40℃ for 10 hours. Cool it to room temperature and filter out the solid product to obtain the pretreated beads for later use.

[0053] (2) Mix the silane coupling agent KH560 with ethanol (mass fraction 85%) and stir evenly to obtain an ethanol solution with a mass fraction of 0.5% of the silane coupling agent. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g: 2 ml and stir evenly. After standing for 30 minutes, heat to 40°C and dry for 10 minutes to obtain the modified fly ash floating beads for later use.

[0054] (3) Take the following raw materials in the following proportions: 108 parts by weight of styrene monomer, 0.7 parts by weight of dibenzoyl peroxide, 2.3 parts by weight of polyethylene wax, 12 parts by weight of the modified fly ash beads prepared in this example, and 9.5 parts by weight of isopentane. Mix the above raw materials evenly, heat to 90°C for prepolymerization for 30 minutes, then heat to 180°C for mixing for 0.5 hours, then cool to 130°C and extrude for granulation to obtain modified polystyrene particles with a particle size of 1 mm.

[0055] (4) Add 2% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 60° C. for 30 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0056] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board by an extruder, and then the impact strength, limiting oxygen index and thermal conductivity of the insulation board are tested by the same method as in the above embodiment 1. The results are shown in the following table; .

[0057] Example 7 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads were mixed with 0.4 mol / L sodium hydroxide solution at a ratio of 1 g:15 ml, and then stirred continuously for 60 min at a stirring rate of 30 r / min. Then the fly ash floating beads were filtered out, added to a container with saturated lime water at a ratio of 1 g:30 ml, and stirred evenly. After sealing, the mixture was heated in a water bath to 55°C for 8 hours, cooled to room temperature, and the solid product was filtered out to obtain pre-treated floating beads for later use.

[0058] (2) The pretreated floating beads are mixed with 90% by mass ethanol in a ratio of 1 g:1 ml and stirred evenly. After standing for 20 min, the mixture is heated to 50° C. and dried for 7 min to remove the ethanol, thereby obtaining the modified fly ash floating beads for later use.

[0059] (3) Take the following raw materials in the following proportions: 100 parts by weight of styrene monomer, 0.45 parts by weight of benzoyl peroxide, 1.5 parts by weight of polyethylene wax, 10 parts by weight of the modified fly ash beads prepared in this example, and 8 parts by weight of n-pentane. Mix the above raw materials evenly, heat to 85°C for prepolymerization for 40 minutes, then heat to 170°C for mixing for 1 hour, then cool to 120°C and extrude for granulation to obtain modified polystyrene particles with a particle size of 1 mm.

[0060] (4) Add 3% by weight of silica sol to the modified polystyrene particles, stir evenly, and dry at 50° C. for 35 minutes to obtain a modified polystyrene high-strength flame-retardant thermal insulation material.

[0061] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board by an extruder, and then the impact strength, limiting oxygen index and thermal conductivity of the insulation board are tested by the same method as in the above embodiment 1. The results are shown in the following table; .

[0062] Example 8 A preparation method of a modified polystyrene high-strength flame-retardant thermal insulation material comprises the following steps: (1) Fly ash floating beads were mixed with 0.3 mol / L sodium hydroxide solution at a ratio of 1 g: 20 ml, and then stirred continuously for 50 min at a stirring rate of 40 r / min. Then the fly ash floating beads were filtered out, added to a container with saturated lime water at a ratio of 1 g: 20 ml, and stirred evenly. After sealing, the mixture was heated in a water bath to 40°C for 10 hours, cooled to room temperature, and the solid product was filtered out to obtain pre-treated floating beads for later use.

[0063] (2) Mix the silane coupling agent KH560 with ethanol (mass fraction 85%) and stir evenly to obtain an ethanol solution with a mass fraction of 0.5% of the silane coupling agent. Mix the pretreated floating beads with the ethanol solution in a ratio of 1 g: 2 ml and stir evenly. After standing for 30 minutes, heat to 40°C and dry for 10 minutes to obtain the modified fly ash floating beads for later use.

[0064] (3) Take the following raw materials in the following proportions: 108 parts by weight of styrene monomer, 0.7 parts by weight of dibenzoyl peroxide, 2.3 parts by weight of polyethylene wax, 12 parts by weight of the modified fly ash beads prepared in this example, and 9.5 parts by weight of isopentane. Mix the above raw materials evenly, heat to 90°C for prepolymerization for 30 minutes, then heat to 180°C for mixing for 0.5 hours, then cool to 130°C and extrude and granulate to obtain a modified polystyrene high-strength flame-retardant thermal insulation material with a particle size of 1 mm.

[0065] Performance test: The modified polystyrene high-strength flame-retardant thermal insulation material prepared in this embodiment is processed into an insulation board by an extruder, and then the impact strength, limiting oxygen index and thermal conductivity of the insulation board are tested by the same method as in the above embodiment 1. The results are shown in the following table; .

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a modified polystyrene high-strength flame-retardant thermal insulation material, characterized in that: The steps include: (1) placing fly ash floating beads in an alkali solution and continuously stirring the beads, and then placing the obtained floating beads in saturated lime water and keeping them warm under heating conditions, and after completion, obtaining pre-treated floating beads; (2) uniformly mixing the pretreated floating beads with ethanol containing a silane coupling agent, allowing the mixture to stand and then drying to remove the ethanol, thereby obtaining modified fly ash floating beads; (3) Using styrene monomer, initiator, nucleating agent, the modified fly ash floating beads and foaming agent as raw materials; mixing the above raw materials evenly, heating and kneading, and then extruding and granulating to obtain modified polystyrene particles; (4) The modified polystyrene particles are mixed with silica sol and stirred evenly, and dried to obtain the modified polystyrene high-strength flame-retardant thermal insulation material.

2. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (1), the ratio of the fly ash floating beads to the alkali solution is 1 g: 10-20 ml; optionally, the concentration of the alkali solution is 0.3-0.5 mol / L.

3. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (1), the alkali solution includes at least one of a sodium hydroxide solution and a potassium hydroxide solution; Optionally, in step (1), the continuous stirring treatment time is 45-60 min, and the stirring rate is 50-80 r / min.

4. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (1), the ratio of the floating beads to saturated lime water is 1g:20-40ml.

5. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (1), the heating temperature is 40-60° C. and the insulation time is 7-10 hours.

6. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (2), the ratio of the pretreated floating beads to the ethanol dissolved with the silane coupling agent is 1 g: 1-2 ml; Optionally, in step (2), the mass fraction of the silane coupling agent in the ethanol is 0.2-0.5%, and the mass fraction of the ethanol is 85-95%; Optionally, in step (2), the silane coupling agent includes at least one of kh550, kh560, and kh570; Optionally, in step (2), the standing time is 20-30 min, the drying temperature is 40-50° C., and the drying time is 5-10 min.

7. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (3), the proportions of the raw materials are: 94-108 parts by weight of styrene monomer, 0.4-0.7 parts by weight of initiator, 1-2.3 parts by weight of nucleating agent, 8-12 parts by weight of modified fly ash floating beads, and 6-9.5 parts by weight of foaming agent; Optionally, the initiator includes any one of benzoyl peroxide, dibenzoyl peroxide, and dicumyl peroxide; Optionally, the nucleating agent includes any one of phenolic resin and polyethylene wax; Optionally, the foaming agent includes any one of n-pentane, isopentane and neopentane.

8. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to claim 1, characterized in that: In step (3), prepolymerization is first performed at 80-90°C for 0.5-1 hour, then the temperature is raised to 160-180°C for kneading for 0.5-1.5 hours, and then the temperature is lowered to 100-130°C for extrusion granulation.

9. The preparation process of the modified polystyrene high-strength flame-retardant thermal insulation material according to any one of claims 1 to 8, characterized in that: In step (4), the silica sol is 2-3.5% of the mass of the modified polystyrene particles; Optionally, in step (4), the drying temperature is 50-60° C. and the drying time is 30-40 min.

10. Application of the modified polystyrene high-strength flame-retardant thermal insulation material obtained by the preparation process according to any one of claims 1 to 9 in the fields of construction, food, chemical industry or agriculture.

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