Flame-retardant rigid polyurethane foam thermal insulation material and preparation method thereof

Abstract

The invention discloses a flame-retardant rigid polyurethane foam thermal insulation material and a preparation method thereof, and belongs to the crossing field of solid waste resource utilization and halogen-free flame retardance. The thermal insulation material is prepared from the following components in parts by mass: 50 to 150 parts of polyol, 120 to 200 parts of polyisocyanate, 0.2 to 1 part of an organic tin catalyst, 0.5 to 3 parts of a foam stabilizer, 0.5 to 2 parts of an amine catalyst, 0.5 to 5 parts of a chemical foaming agent, 5 to 50 parts of a physical foaming agent, 5 to 50 parts of a transition metal chelated polydopamine modified steel slag flame retardant and 10 to 70 parts of a halogen-free flame retardant. The flame-retardant rigid polyurethane foam thermal insulation material is prepared by modifying the steel slag through chelating the transition metal with the polydopamine and combining with the halogen-free flame retardant. According to the invention, the flame-retardant function of the halogen-free flame retardant is efficiently realized, the synergistic flame-retardant characteristic of the steel slag is fully exerted, and the release of smoke and toxic substances is remarkably reduced. The innovative technology promotes the high-added-value utilization of the steel slag, successfully overcomes the defects of the traditional rigid polyurethane foam thermal insulation material in the aspects of cost and fire safety performance, has wide application potential, and is suitable for multiple fields such as building outer walls, cold-chain logistics and pipeline thermal insulation.

Description

Technical Field

[0001] The present invention belongs to the intersection of solid waste resource utilization and halogen-free flame retardant, and specifically relates to a flame-retardant, smoke-suppressing, and toxic-reducing exterior wall insulation material and a preparation method thereof. In particular, it relates to a flame-retardant rigid polyurethane foam insulation material prepared by using a transition metal chelated polydopamine modified steel slag flame retardant in conjunction with a halogen-free flame retardant. Background Art

[0002] Rigid polyurethane foam (RPUF) is a polymer insulation material with excellent performance. Due to its low thermal conductivity and low density, RPUF performs well in thermal insulation and can effectively reduce energy consumption. Therefore, it has been widely used in many fields such as construction, automobiles, and home appliances. Its high specific strength and convenient construction make RPUF also have good adaptability in various complex shape applications, greatly improving construction efficiency and material utilization. However, RPUF has certain shortcomings in fire resistance, and its limiting oxygen index is usually between 17% and 18%. This means that in an environment with low oxygen concentration, RPUF may be more likely to cause combustion. Defects such as dripping and release of toxic fumes (such as carbon monoxide and hydrocyanic acid) during combustion not only harm the environment, but also pose a threat to personal safety. These problems have limited the scope of application of RPUF to a certain extent, especially in the construction and industrial fields with high requirements for fire resistance.

[0003] The steel industry has always been a pillar industry in my country, playing an important role in safeguarding the national economy, national defense construction, and social stability. As the main by-product of the steelmaking process, the large amount of steel slag not only occupies a large amount of land, but also pollutes the surrounding atmosphere and soil environment. The current research on the diversified utilization of steel slag has achieved some results, and many key technologies are becoming more mature, such as road construction and concrete preparation. However, there are still many problems to be solved in the process of steel slag utilization, such as poor stability and low activity of steel slag. Therefore, other ways to utilize steel slag should be explored on the basis of existing steel slag utilization technology to improve its resource utilization efficiency and make steel slag a valuable secondary resource in my country. Therefore, how to utilize steel slag resources in a high-value way has become the focus of attention in the industry.

[0004] Polydopamine (PDA) is a biomass polymer formed by self-polymerization of dopamine monomers in an alkaline environment. It has excellent surface modification properties and good biocompatibility. In recent years, the application of PDA in the field of flame retardancy has attracted widespread attention, especially in improving the fire resistance of materials. The surface of PDA is rich in catechol groups and amino groups, and these functional groups enable it to form a stable coating on almost all solid surfaces. This strong adhesion ability not only enhances the adhesion of the material, but also enables it to effectively combine with a variety of different types of substrate materials (such as plastics, metals, fibers, etc.), providing a basis for subsequent flame retardant modification. In fire protection applications, PDA coatings can effectively improve the flame retardant properties of the substrate and reduce its burning rate and smoke release under high temperature conditions. In terms of complexation with metal ions and non-metal ions, PDA exhibits good functionality, which provides a basis for its synergistic effect with flame retardants. Studies have shown that certain metal ions (such as aluminum, zinc, etc.) can interact with the functional groups in the PDA coating to form an enhanced composite material. This synergistic effect not only enhances the flame retardancy of the material but also potentially improves its other physicochemical properties, such as heat resistance and mechanical strength.

[0005] Metal ions are generally highly thermally stable, which prevents volatilization during processing and may reduce or prevent the release of pollutants or toxic chemicals into the environment. Transition metals refer to a series of metal elements in the d block of the periodic table, also known as transition elements. Redox-active transition metal ions, such as Fe 3+ 、Co 2+ 、Ni 2+ and Zn 2+, which can promote catalytic pyrolysis and carbonization through cyclization, cross-linking, aromatization and carbonization. In addition, these elements can inhibit the emission of environmentally harmful combustion products by oxidizing volatile or gaseous intermediates. Transition metal ions can participate in reactions involving multi-orbital electrons (including d and f orbitals), resulting in a catalytic effect that reduces the reaction energy and significantly increases the reaction rate. In particular, cheap transition metals such as Fe have significant catalytic oxidation properties through electron transfer and proton coupling. Incorporating transition metal components into flame retardants helps the catalytic conversion of smoke, thereby reducing the diversity and concentration of harmful gases, thereby alleviating the adverse effects of smoke. Therefore, transition metals have significant application prospects in the field of flame retardancy. Steel slag is rich in metal oxides and non-metal oxides, the main components of which are calcium oxide (CaO), silicon oxide (SiO2), aluminum oxide (Al2O3), and iron oxide (Fe2o3). It also contains a small amount of magnesium oxide (MgO) and zinc oxide (ZnO). If it is reasonably modified, it has the potential to become a flame retardant. Steel slag is modified by polydopamine (PDA), and PDA is used as a bridge to complex transition metals on the SS surface to prepare flame retardants. The flame retardant effect of polymer materials can be effectively improved through flame retardant synergy. At the same time, the active sites formed by transition metals can effectively reduce the release of toxic gases such as carbon monoxide during combustion through oxidation-reduction cycles. This method not only effectively utilizes steel slag resources, but also provides a new idea for improving the flame retardant properties of polymers.

[0006] At present, the application of transition metal chelated polydopamine modified steel slag flame retardant in polymer material products, especially rigid polyurethane foam, in the fields of flame retardant synergy and smoke suppression and toxicity reduction is not yet mature, and the high-value utilization of steel slag needs to be further explored. Summary of the invention

[0007] The present invention aims at the technical bottlenecks of low efficiency of traditional halogen-free flame retardant rigid polyurethane foam, large amount of toxic smoke generated during combustion, large amount of steel slag accumulation, low added value, etc., and provides a flame retardant rigid polyurethane foam based on transition metal chelated polydopamine modified steel slag flame retardant and halogen-free flame retardant and a preparation method thereof, so that the flame retardant rigid polyurethane foam insulation material has excellent flame retardant performance and smoke suppression and toxicity reduction performance, and at the same time realizes the high-value utilization of steel slag.

[0008] The present invention is achieved through the following technical solutions.

[0009] The present invention provides a flame retardant rigid polyurethane foam thermal insulation material, wherein the thermal insulation raw material is composed of the following components in parts by mass:

[0010]

[0011] The transition metal chelated polydopamine modified steel slag flame retardant is composed of the following parts by mass:

[0012]

[0013] The organotin catalyst is one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate;

[0014] The foam stabilizer is a silicone oil surfactant

[0015]

[0016] One or more of;

[0017] The amine catalyst is one or more of triethylamine, triethanolamine, pentamethyldiethylenetriamine (Polycat 5), N,N-dimethylcyclohexylamine (Polycat 8), tris(dimethylaminopropyl)amine (Polycat 9), tris(dimethylaminopropyl)hexahydrotriazine (Polycat 41), Dabco BL 11 (70% bis(dimethylaminoethyl) ether and 30% dipropylene glycol mixture), A33 (33wt% triethylenediamine);

[0018] The chemical foaming agent is one or more of purified water, dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate;

[0019] The physical foaming agent is one or more of cyclopentane, n-pentane, isopentane, butane, 1,1,1,2-tetrafluoroethane (HFC-134A), pentafluoropropane (HFC-245FA), pentafluorobutane (HFC-365MFC), heptafluoropropane (HFC-227EA), dichloromonofluoroethane (HCFC-141B), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233ZD), and 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336MZZ);

[0020] The chemical solvent is deionized water, anhydrous ethanol or a mixture thereof.

[0021] Furthermore, the transition metal salt is one or more of an iron metal salt, a cobalt metal salt, a nickel metal salt, a palladium metal salt, and a platinum metal salt.

[0022] Furthermore, the halogen-free flame retardant is one or more of ammonium polyphosphate, piperazine pyrophosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and melamine polyphosphate.

[0023] Furthermore, the polyol is a polyester polyol having a hydroxyl value of 300-500 mg KOH / g or a polyether polyol having a hydroxyl value of 380-500 mg KOH / g, or a mixture thereof.

[0024] Furthermore, the polyisocyanate is a polymethylene polyphenyl polyisocyanate having an NCO group mass percentage of 29.5-32.5 wt %.

[0025] The present invention also provides a method for preparing the flame retardant rigid polyurethane foam thermal insulation material, which specifically comprises the following steps:

[0026] (1) Preparation of transition metal chelated polydopamine modified steel slag (SS@PDA-R): at room temperature, steel slag is mixed with a chemical solvent, ultrasonically treated for 0.5-3h to uniformly disperse the steel slag particles, then anhydrous ethanol and ammonia water are added to the dispersion, and slowly stirred at 25-50°C for 10-60min, then dopamine hydrochloride and transition metal salt are dissolved in the chemical solvent, the resulting solution is added to the above dispersion and adjusted to pH 6-10 with ammonia water at 25-50°C, and then vigorously stirred at 100-500r / min for 24h. After the reaction is completed, the resulting mixed solution is centrifuged 3-7 times with a specific solution, and dried at 40-80°C to obtain transition metal chelated polydopamine modified steel slag;

[0027] The specific solution is one of anhydrous ethanol and deionized water or a mixture thereof;

[0028] (2) Preparation of flame-retardant rigid polyurethane foam insulation material: At 25-30°C, add polyol, polyisocyanate, organotin catalyst, foam stabilizer, amine catalyst, chemical foaming agent, physical foaming agent, transition metal chelated polydopamine modified steel slag flame retardant and halogen-free flame retardant into a stirring device in sequence, stir at high speed until uniform and with wire drawing, then inject into a mold for foaming. After the foam is formed, take out the foam and place it in an oven for maturation to obtain a flame-retardant rigid polyurethane foam insulation material.

[0029] Furthermore, in step (1), the mass ratio of the steel slag to the chemical solvent is 1:2-1:20.

[0030] Furthermore, in step (1), the volume ratio of the chemical solvent to anhydrous ethanol is 1:1-10:1; and the volume ratio of anhydrous ethanol to aqueous ammonia is 5:1-20:1.

[0031] Furthermore, in step (1), the mass ratio of dopamine hydrochloride to metal salt is 1:5-5:1; the mass ratio of dopamine hydrochloride to chemical solvent is 1:50-1:5.

[0032] Furthermore, in step (2), the stirring speed is 200-3500 r / min; the stirring time is 3-40 s; the aging temperature is 40-90° C.; and the aging time is 0.5-24 h.

[0033] The innovative features of the present invention are as follows:

[0034] 1. The transition metal chelated polydopamine modified steel slag (SS@PDA-R) of the present invention has a synergistic effect between the transition metal ions inside it and the metal oxides (such as CaO, Al2O3, Fe2O3) and non-metallic oxides (such as SiO2) in the steel slag, which effectively promotes the thermal cross-linking reaction of the polyurethane molecular chain. This reaction significantly reduces the generation of combustible gases and forms a dense graphitized carbon layer in the combustion area. The carbon layer not only effectively blocks the entry of oxygen and combustible gases, but also inhibits the transfer of heat, thereby significantly enhancing the flame retardant properties of the material.

[0035] 2. The active sites of transition metal elements in the transition metal chelated polydopamine modified steel slag (SS@PDA-R) of the present invention have good redox cycle characteristics, that is, high-valent ions are reduced to low-valent ions by carbon monoxide after one cycle, and then oxidized back to high-valent ions by oxygen, thereby reducing carbon monoxide emissions and effectively inhibiting the release of toxic gases during combustion. This characteristic enhances the chemical stability of the material in a high-temperature environment by promoting electron transfer reactions, thereby significantly reducing the generation of harmful gases and improving overall safety.

[0036] Compared with the prior art, the present invention has the following technical effects:

[0037] 1. The present invention prepares transition metal chelated polydopamine modified steel slag (SS@PDA-R) by grafting transition metal with polydopamine coated steel slag, effectively exerts its flame retardant synergistic effect, and significantly enhances the flame retardant efficiency. Compared with pure rigid polyurethane foam, the flame retardant rigid polyurethane foam with transition metal chelated polydopamine modified steel slag flame retardant has a limiting oxygen index higher than 23.5vo1%, and the vertical combustion level is UL-94V-0 level.

[0038] 2. The present invention solves the problem of low flame retardant efficiency when traditional halogen-free flame retardants are added alone to rigid polyurethane foam. Through the synergistic effect of transition metal chelated polydopamine modified steel slag and halogen-free flame retardants such as ammonium polyphosphate, the prepared polyurethane building insulation material has excellent flame retardant, smoke suppression and compression resistance. Among them, the active sites formed by the transition metal elements can be circulated through redox reactions, effectively inhibiting the production of toxic fumes such as carbon monoxide during combustion, and have obvious smoke suppression and toxicity reduction effects. The total CO production during the combustion of rigid polyurethane foam added with transition metal chelated polydopamine modified steel slag flame retardant decreased by more than 52% compared with pure rigid polyurethane foam.

[0039] 3. On the basis of achieving high-efficiency flame retardancy and significant smoke suppression and toxicity reduction, the present invention further improves the compressive strength and thermal insulation performance of the material compared with the prior art. This means that in practical applications, the material of the present invention can not only better resist pressure and ensure structural stability, but also provide better thermal insulation effects and meet the use requirements in more complex scenarios.

[0040] 4. The present invention not only efficiently realizes the flame retardant function of halogen-free flame retardants, but also gives full play to the synergistic flame retardant properties of steel slag, significantly reducing the release of smoke and toxic substances. This innovative technology promotes the high added value utilization of steel slag, successfully overcomes the shortcomings of traditional rigid polyurethane foam insulation materials in terms of cost and fire safety performance, and has a wide range of application potentials, suitable for building exterior walls, cold chain logistics, pipeline insulation and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart for preparing the transition metal chelated polydopamine modified steel slag flame retardant.

[0042] Figure 2 This is a scanning electron microscope photograph of the transition metal chelated polydopamine modified steel slag in Example 1 of the present invention (wherein a is steel slag, b is steel slag modified by iron ion chelated polydopamine, c is steel slag modified by cobalt ion chelated polydopamine, and d is steel slag modified by nickel ion chelated polydopamine).

[0043] Figure 3 This is a graph showing the change in heat release rate over time of pure rigid polyurethane foam, flame retardant rigid polyurethane foam-1, flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3, and flame retardant rigid polyurethane foam-4 obtained by cone calorimetry test.

[0044] Figure 4 This is a curve chart of total smoke generation versus time of pure rigid polyurethane foam, flame retardant rigid polyurethane foam-1, flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3, and flame retardant rigid polyurethane foam-4 obtained by cone calorimetry test. DETAILED DESCRIPTION

[0045] In order to further illustrate the technical solution of the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention. Based on the examples in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0046] Example 1

[0047] The flame-retardant rigid polyurethane foam of halogen-free flame retardant prepared in this embodiment and its preparation method are to prepare polydopamine-modified steel slag through bio-based polydopamine, prepare transition metal chelated polydopamine-modified steel slag flame retardant through the complexation between polydopamine-modified steel slag and transition metal ions, and then stir the transition metal chelated polydopamine-modified steel slag flame retardant, halogen-free flame retardant with polyol, amine catalyst, organic tin catalyst, chemical foaming agent, physical foaming agent, foam stabilizer and polyisocyanate at high speed until wire drawing occurs, and prepare flame-retardant rigid polyurethane foam insulation material by aging in an oven. Among them, ammonium polyphosphate is selected as the halogen-free flame retardant, and ferric nitrate is selected as the metal salt used to prepare the transition metal chelated polydopamine-modified steel slag flame retardant. The flame-retardant rigid polyurethane foam insulation material is prepared according to the following steps:

[0048] Step S1: at room temperature (25°C), 10 g of steel slag was mixed with 90 mL of deionized water, and ultrasonic treatment was performed for 1 h to uniformly disperse the steel slag particles. Subsequently, 40 mL of anhydrous ethanol and 3 mL of ammonia water were added to the dispersion, and the mixture was slowly stirred at 30°C for 30 min. Subsequently, 500 mg of dopamine hydrochloride and 606 mg of ferric nitrate were dissolved in a chemical solvent, and the resulting solution was added to the above dispersion and the pH of the solution was adjusted to 8.5 with ammonia water at 30°C, and then vigorously stirred at 300 r / min for 24 h. After the reaction was completed, the resulting mixed solution was centrifuged 3 times with a specific solution, and dried at 60°C for 12 h to obtain iron ion chelated polydopamine modified steel slag;

[0049] Step S2: at 30°C, 100 parts of polyester polyol with a hydroxyl value of 430 mgKOH / g, 1 part of amine catalyst Polycat 5, 0.5 parts of organic tin catalyst dibutyltin dilaurate, 2 parts of chemical foaming agent dimethyl carbonate, 30 parts of physical foaming agent 1,1,1,2-tetrafluoroethane (HFC-134A), and 1.5 parts of foam stabilizer are added to the stirrer in sequence. 6 parts of iron ion chelated polydopamine modified steel slag, 24 parts of ammonium polyphosphate and 138 parts of polyisocyanate with an NCO content of 30.5wt% are stirred at a high speed of 1000r / min for 10s until they are uniform and have a wire drawing phenomenon, and then injected into a mold for foaming. After the foam is formed, the foam is taken out and placed in an oven at 60°C for ripening for 5h to obtain a flame retardant rigid polyurethane foam insulation material, which is marked as flame retardant rigid polyurethane foam-2.

[0050] Comparative Example 1

[0051] At 30°C, 100 parts of polyester polyol with a hydroxyl value of 430 mgKOH / g, 1 part of amine catalyst Polycat 5, 0.5 parts of organic tin catalyst dibutyltin dilaurate, 2 parts of chemical foaming agent dimethyl carbonate, 30 parts of physical foaming agent 1,1,1,2-tetrafluoroethane (HFC-134A), and 1.5 parts of foam stabilizer were added to the stirrer in sequence. 138 parts of polyisocyanate with an NCO content of 30.5wt% are stirred at 1000r / min for 10s until it is uniform and has a wire drawing phenomenon, then injected into a mold for foaming. After the foam is formed, the foam is taken out and placed in an oven at 60°C for aging for 5h to obtain a pure rigid polyurethane foam insulation material, which is marked as pure rigid polyurethane foam.

[0052] Comparative Example 2

[0053] At 30°C, 100 parts of polyester polyol with a hydroxyl value of 430 mgKOH / g, 1 part of amine catalyst Polycat 5, 0.5 parts of organic tin catalyst dibutyltin dilaurate, 2 parts of chemical foaming agent dimethyl carbonate, 30 parts of physical foaming agent 1,1,1,2-tetrafluoroethane (HFC-134A), and 1.5 parts of foam stabilizer were added to the stirrer in sequence. 6 parts of steel slag, 24 parts of ammonium polyphosphate, and 138 parts of polyisocyanate with an NCO content of 30.5wt% are stirred at a high speed of 1000r / min for 10s until they are uniform and have a wire drawing phenomenon, then injected into a mold for foaming. After the foam is formed, the foam is taken out and placed in an oven at 60°C for ripening for 5h to obtain a flame retardant rigid polyurethane foam insulation material, which is marked as flame retardant rigid polyurethane foam-1.

[0054] Example 2

[0055] The flame-retardant rigid polyurethane foam of halogen-free flame retardant prepared in this embodiment and its preparation method are to prepare polydopamine-modified steel slag through bio-based polydopamine, prepare transition metal chelated polydopamine-modified steel slag flame retardant through the complexation between polydopamine-modified steel slag and transition metal ions, and then stir the transition metal chelated polydopamine-modified steel slag flame retardant, halogen-free flame retardant with polyol, amine catalyst, organic tin catalyst, chemical foaming agent, physical foaming agent, foam stabilizer and polyisocyanate at high speed until wire drawing occurs, and prepare flame-retardant rigid polyurethane foam insulation material by aging in an oven. Among them, ammonium polyphosphate is selected as the halogen-free flame retardant, and cobalt nitrate is selected as the metal salt used to prepare the transition metal chelated polydopamine-modified steel slag flame retardant, and the flame-retardant rigid polyurethane foam insulation material is prepared according to the following steps:

[0056] Step S1: at room temperature (25°C), 10g of steel slag was mixed with 90mL of deionized water, and ultrasonic treatment was performed for 1h to uniformly disperse the steel slag particles, and then 40mL of anhydrous ethanol and 3mL of ammonia water were added to the dispersion, and the mixture was slowly stirred at 30°C for 30min, and then 500mg of dopamine hydrochloride and 606mg of cobalt nitrate were dissolved in a chemical solvent, and the resulting solution was added to the above dispersion and the pH of the solution was adjusted to 8.5 with ammonia water at 30°C, and then vigorously stirred at 300r / min for 24h. After the reaction was completed, the resulting mixed solution was centrifuged 3 times with a specific solution, and dried at 60°C for 12h to obtain cobalt ion chelated polydopamine modified steel slag;

[0057] Step S2: at 30° C., 100 parts of polyester polyol with a hydroxyl value of 430 mg KOH / g, 1 part of amine catalyst Polycat 5, 0.5 parts of organotin catalyst dibutyltin dilaurate, 2 parts of chemical foaming agent dimethyl carbonate, 30 parts of physical foaming agent 1,1,1,2-tetrafluoroethane (HFC-134A), and 1.5 parts of foam stabilizer are added into the stirrer in sequence. 6 parts of cobalt ion chelated polydopamine modified steel slag, 24 parts of ammonium polyphosphate and 138 parts of polyisocyanate with an NCO content of 30.5wt% are stirred at a high speed of 1000r / min for 10s until they are uniform and have a wire drawing phenomenon, and then injected into a mold for foaming. After the foam is formed, the foam is taken out and placed in an oven at 60°C for ripening for 5h to obtain a flame retardant rigid polyurethane foam insulation material, which is marked as flame retardant rigid polyurethane foam-3.

[0058] Example 3

[0059] The flame-retardant rigid polyurethane foam of halogen-free flame retardant prepared in this embodiment and its preparation method are to prepare polydopamine-modified steel slag through bio-based polydopamine, prepare transition metal chelated polydopamine-modified steel slag flame retardant through the complexation between polydopamine-modified steel slag and transition metal ions, and then stir the transition metal chelated polydopamine-modified steel slag flame retardant, halogen-free flame retardant with polyol, amine catalyst, organic tin catalyst, chemical foaming agent, physical foaming agent, foam stabilizer and polyisocyanate at high speed until wire drawing occurs, and ripen in an oven to prepare flame-retardant rigid polyurethane foam insulation material. Among them, ammonium polyphosphate is selected as the halogen-free flame retardant, and nickel nitrate is selected as the metal salt used to prepare the transition metal chelated polydopamine-modified steel slag flame retardant. The flame-retardant rigid polyurethane foam insulation material is prepared according to the following steps:

[0060] Step S1: at room temperature (25°C), 10g of steel slag was mixed with 90mL of deionized water, and ultrasonic treatment was performed for 1h to uniformly disperse the steel slag particles, and then 40mL of anhydrous ethanol and 3mL of ammonia water were added to the dispersion, and the mixture was slowly stirred at 30°C for 30min, and then 500mg of dopamine hydrochloride and 606mg of nickel nitrate were dissolved in a chemical solvent, and the resulting solution was added to the above dispersion and the pH of the solution was adjusted to 8.5 with ammonia water at 30°C, and then vigorously stirred at 300r / min for 24h. After the reaction was completed, the resulting mixed solution was centrifuged 3 times with a specific solution, and dried at 60°C for 12h to obtain nickel ion chelated polydopamine modified steel slag;

[0061] Step S2: at 30°C, 100 parts of polyester polyol with a hydroxyl value of 430 mgKOH / g, 1 part of amine catalyst Polycat 5, 0.5 parts of organic tin catalyst dibutyltin dilaurate, 2 parts of chemical foaming agent dimethyl carbonate, 30 parts of physical foaming agent 1,1,1,2-tetrafluoroethane (HFC-134A), and 1.5 parts of foam stabilizer are added to the stirrer in sequence. 6 parts of nickel ion chelated polydopamine modified steel slag, 24 parts of ammonium polyphosphate and 138 parts of polyisocyanate with an NCO content of 30.5wt% are stirred at a high speed of 1000r / min for 10s until they are uniform and have a wire drawing phenomenon, and then injected into a mold for foaming. After the foam is formed, the foam is taken out and placed in an oven at 60°C for ripening for 5h to obtain a flame retardant rigid polyurethane foam insulation material, which is marked as flame retardant rigid polyurethane foam-4.

[0062] Figure 1This is a flow chart for preparing the transition metal chelated polydopamine modified steel slag flame retardant of the present invention. As shown in the figure, the present invention mixes steel slag with deionized water, adds anhydrous ethanol and ammonia water to the dispersion after ultrasonic treatment, slowly stirs for 30 minutes, dissolves dopamine hydrochloride and metal salt in a chemical solvent, adds the obtained solution to the above dispersion, adjusts the solution pH to 8.5 with ammonia water under water bath heating conditions, and then vigorously stirs at a speed of 300r / min for 24 hours to obtain transition metal chelated polydopamine modified steel slag.

[0063] Figure 2 This is a scanning electron microscope photo of the transition metal chelated polydopamine modified steel slag in Example 1 of the present invention, wherein a is steel slag, b is iron ion chelated polydopamine modified steel slag, c is cobalt ion chelated polydopamine modified steel slag, and d is nickel ion chelated polydopamine modified steel slag. Figure 2 It can be seen that the steel slag powder presents an obvious granular structure and is evenly dispersed; while the powder ( Figure 2 (b), 2(c), and 2(d)) show a significant change in the appearance structure compared to SS, and they all present a cohesive block structure, which is mainly attributed to the adhesion of dopamine. The above structure further enhances the synergistic flame retardant and smoke suppression and toxicity reduction effects of transition metal chelated polydopamine modified steel slag.

[0064] Figure 3 The heat release rate curves of pure rigid polyurethane foam, flame retardant rigid polyurethane foam-1, flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3, and flame retardant rigid polyurethane foam-4 obtained by cone calorimetry test are as high as 553.5kW / m 2 ; The peak heat release rate of flame retardant rigid polyurethane foam-1 decreased by 175.7kW / m 2 The peak heat release rates of flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3 and flame retardant rigid polyurethane foam-4 were reduced by 127.7kW / m 2 、178.8kW / m 2 and 174.1kW / m 2The results showed that the compounding of ammonium polyphosphate and transition metal chelated polydopamine modified steel slag reduced the heat release rate of the composite material to a certain extent, and effectively improved the fire safety of the composite material. Among them, the peak heat release rate of the flame-retardant rigid polyurethane foam-3 with the addition of cobalt ion chelated polydopamine modified steel slag was most significantly reduced, which was 32.3% lower than that of the pure rigid polyurethane foam. The heat release of the flame-retardant rigid polyurethane foam-3 gradually decreased after reaching the peak heat release rate, indicating that the flame retardant efficiency of the steel slag modified by cobalt ion chelated polydopamine can be improved through the flame retardant synergistic effect between the shell steel slag and polydopamine, and between cobalt ions and ammonium polyphosphate. Its flame retardant effect is also significantly better than that of the flame retardant rigid polyurethane foam-1 with the addition of the same amount of steel slag.

[0065] Figure 4 The total smoke generation curves of pure rigid polyurethane foam, flame retardant rigid polyurethane foam-1, flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3, and flame retardant rigid polyurethane foam-4 obtained by cone calorimetry test over time. It can be seen that the final total smoke generation of pure rigid polyurethane foam is 976.7m 2 / m 2 After adding steel slag, the final total smoke volume of flame retardant rigid polyurethane foam-1 is 840.4m 2 / m 2 The results show that the addition of steel slag and ammonium polyphosphate can effectively inhibit the generation of smoke particles during the combustion of rigid polyurethane foam. After adding equal amounts of transition metal chelated polydopamine modified steel slag and ammonium polyphosphate, the final total smoke generation of flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3 and flame retardant rigid polyurethane foam-4 is 787.8m 2 / m 2 、817.8m 2 / m 2 and 813.8m 2 / m 2 , decreased by 6.3%, 2.7% and 3.2% respectively compared with the flame retardant rigid polyurethane foam-1, among which the flame retardant rigid polyurethane foam-2 with iron ion chelated polydopamine modified steel slag had the best smoke suppression effect. This shows that transition metal chelated polydopamine modified steel slag can effectively inhibit the generation of toxic smoke particles during the combustion of rigid polyurethane foam and improve its fire safety performance.

[0066] Table 1 shows the flame retardant properties, mechanical properties, thermal insulation properties and total CO production test results of pure rigid polyurethane foam, flame retardant rigid polyurethane foam-1, flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3 and flame retardant rigid polyurethane foam-4. As shown in Table 1, after adding iron ion chelated polydopamine modified steel slag and ammonium polyphosphate, the compressive strength of flame retardant rigid polyurethane foam-2 is 0.351MPa, the thermal conductivity is only 0.0318W / m·k, its limiting oxygen index is as high as 23.6vo1%, the vertical combustion level is UL-94V-0 level, and the total CO production is 1.379g; after adding cobalt ion chelated polydopamine modified steel slag and ammonium polyphosphate, the compressive strength of flame retardant rigid polyurethane foam-3 is 0.347MPa, the thermal conductivity is only 0.030.6W / m·k, its limiting oxygen index is as high as 23.5vol%, the vertical combustion level is UL-94V-0 level, and the total CO production is 0.825g; after adding nickel ion chelated polydopamine modified steel slag and ammonium polyphosphate, the compressive strength of flame retardant rigid polyurethane foam-4 is 0.367MPa, the thermal conductivity is only 0.0319W / m·k, its limiting oxygen index is as high as 23.7vol%, the vertical combustion level is UL-94V-0 level, and the total CO production is 1.247g. After adding steel slag and ammonium polyphosphate, the compressive strength of flame retardant rigid polyurethane foam-1 is 0.274MPa, the thermal conductivity is only 0.0323W / m·k, its limiting oxygen index is as high as 22.3vol%, the vertical combustion level is UL-94V-1 level, and the total CO production is 1.359g. The data show that the flame retardant properties, compressive strength and total CO production of flame retardant rigid polyurethane foam-2, flame retardant rigid polyurethane foam-3 and flame retardant rigid polyurethane foam-4 are significantly better than those of pure rigid polyurethane foam and flame retardant rigid polyurethane foam-1 in the comparative example, and their thermal insulation properties are significantly better than those of pure rigid polyurethane foam. This indicates that transition metal chelated polydopamine modified steel slag can significantly improve the flame retardant properties, compressive strength, thermal insulation properties and reduce CO production of rigid polyurethane foam.

[0067] Table 1 Test results of flame retardancy, mechanical properties, thermal insulation properties and total CO production of various polyurethane foams

[0068]

Claims

1. A flame retardant rigid polyurethane foam thermal insulation material, characterized in that: The thermal insulation raw material is composed of the following parts by mass: The transition metal chelated polydopamine modified steel slag flame retardant is composed of the following parts by mass: The organotin catalyst is one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate; The foam stabilizer is a silicone oil surfactant One or more of B8590; The amine catalyst is one or more of triethylamine, triethanolamine, pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, tris(dimethylaminopropyl)amine, tris(dimethylaminopropyl)hexahydrotriazine, Dabco BL 11, and A33; The chemical foaming agent is one or more of purified water, dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; The physical foaming agent is one or more of cyclopentane, n-pentane, isopentane, butane, 1,1,1,2-tetrafluoroethane, pentafluoropropane, pentafluorobutane, heptafluoropropane, monofluorodichloroethane, trans-1-chloro-3,3,3-trifluoropropene, and 1,1,1,4,4,4-hexafluoro-2-butene; The chemical solvent is deionized water, anhydrous ethanol or a mixture thereof.

2. A flame retardant rigid polyurethane foam thermal insulation material as claimed in claim 1, characterized in that: The transition metal salt is one or more of an iron metal salt, a cobalt metal salt, a nickel metal salt, a palladium metal salt, and a platinum metal salt.

3. The flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: The halogen-free flame retardant is one or more of ammonium polyphosphate, piperazine pyrophosphate, aluminum hypophosphite, diethyl aluminum hypophosphite, and melamine polyphosphate.

4. The flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: The polyol is one of polyester polyols having a hydroxyl value of 300-500 mg KOH / g or polyether polyols having a hydroxyl value of 380-500 mg KOH / g, or a mixture thereof.

5. The flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: The polyisocyanate is polymethylene polyphenyl polyisocyanate with an NCO group mass percentage of 29.5-32.5 wt %.

6. The method for preparing a flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that The following steps are involved: (1) Preparation of transition metal chelated polydopamine modified steel slag: at room temperature, steel slag is mixed with a chemical solvent, ultrasonically treated for 0.5-3h to uniformly disperse the steel slag particles, then anhydrous ethanol and ammonia water are added to the dispersion, and slowly stirred at 25-50°C for 10-60min, then dopamine hydrochloride and a transition metal salt are dissolved in the chemical solvent, the resulting solution is added to the above dispersion, and the solution is adjusted to pH 6-10 with ammonia water at 25-50°C, and then vigorously stirred at 100-500r / min for 24h. After the reaction is completed, the resulting mixed solution is centrifuged 3-7 times with a specific solution, and dried at 40-80°C to obtain transition metal chelated polydopamine modified steel slag; The specific solution is one of anhydrous ethanol and deionized water or a mixture thereof; (2) Preparation of flame-retardant rigid polyurethane foam insulation material: At 25-30°C, add polyol, polyisocyanate, organotin catalyst, foam stabilizer, amine catalyst, chemical foaming agent, physical foaming agent, transition metal chelated polydopamine modified steel slag flame retardant and halogen-free flame retardant into a stirring device in sequence, stir at high speed until uniform and with wire drawing, then inject into a mold for foaming. After the foam is formed, take out the foam and place it in an oven for maturation to obtain a flame-retardant rigid polyurethane foam insulation material.

7. The method for preparing a flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: The mass ratio of the steel slag to the chemical solvent in step (1) is 1:2-1:

20.

8. The method for preparing a flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: In step (1), the volume ratio of the chemical solvent to anhydrous ethanol is 1:1-10:1; the volume ratio of the anhydrous ethanol to aqueous ammonia is 5:1-20:

1.

9. The method for preparing a flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: In step (1), the mass ratio of dopamine hydrochloride to metal salt is 1:5-5:1; the mass ratio of dopamine hydrochloride to chemical solvent is 1:50-1:

5.

10. The method for preparing a flame retardant rigid polyurethane foam thermal insulation material according to claim 1, characterized in that: In step (2), the stirring speed is 200-3500 r / min; the stirring time is 3-40 s; the aging temperature is 40-90° C.; and the aging time is 0.5-24 h.

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