Ultra-light flame-retardant rubber foam material as well as preparation method and application thereof

Abstract

The invention relates to the field of high-performance flame-retardant materials and discloses an ultra-light flame-retardant rubber foam material and a preparation method and application thereof.The ultra-light flame-retardant rubber foam material is prepared from modified carboxy nitrile rubber, a foaming agent, a foaming aid, a cross-linking agent, a flame retardant, inorganic filler, tackifying resin and a softening agent; the modified carboxy nitrile rubber is prepared by chemically grafting hexamethylol melamine. According to the invention, a nitrogen-containing structure is introduced into a polymer molecular chain, so that the material has intrinsic flame retardant property, high foaming ratio and light weight are realized, and the problems of density increase and performance degradation caused by high filling of a flame retardant in the traditional technology are avoided. The flame retardant property of the material reaches UL-94 V0 level, and the material is suitable for the fields of building heat preservation, automotive trim, cable sheaths and household appliance shock pads.

Description

Technical Field

[0001] The invention relates to the technical field of high-performance flame-retardant materials, in particular to an ultra-light flame-retardant rubber foam material and a preparation method and application thereof. Background Art

[0002] In the prior art, foam materials are widely used in building insulation, automobile interior, cable sheathing, and home appliance shock pads due to their lightweight, excellent thermal insulation and mechanical properties. However, since foam materials are usually composed of pure organic polymers, their flammability has always been an important factor limiting their application. In order to improve the flame retardant properties of materials, the prior art mainly achieves flame retardant function by adding flame retardants or using halogen-containing flame retardant materials, but these technical solutions have obvious deficiencies in practical applications.

[0003] In traditional flame retardant solutions, halogen-containing materials are widely used because of their high flame retardant efficiency and low addition amount, but this technical method has significant environmental and health problems. Halogen-containing flame retardants release toxic gases such as hydrogen chloride during combustion, which is harmful to human health and the environment. At the same time, with the increasingly stringent environmental regulations, the application of halogen-containing flame retardant materials in the fields of construction, home appliances and automotive interiors is increasingly restricted. In addition, the long-term use of halogen-containing materials may lead to a decrease in flame retardant properties, which further limits the scope of their practical application.

[0004] In order to deal with the above problems, halogen-free flame retardants are gradually being adopted. The flame retardant properties of foam materials can be improved to a certain extent by adding halogen-free flame retardants such as aluminum hydroxide and ammonium polyphosphate, but this technical method requires the addition of a large amount of flame retardants, usually with a filling ratio of up to 30%-50%. A high proportion of flame retardants not only significantly increases the density of the material, but also reduces the foaming ratio of the material, resulting in uneven pore structure and reduced thermal insulation performance. In addition, a high filling amount of flame retardants may destroy the mechanical properties of the material, especially the compression strength and rebound performance, thereby affecting its service life. Although the halogen-free flame retardant solution has improved in terms of environmental protection, it has failed to effectively solve the contradiction between flame retardancy and lightweight.

[0005] In the development of flame-retardant foam materials, the balance between flame retardancy and foaming ratio has always been a technical problem. In the prior art, in order to improve the flame retardant properties of the material, it is often necessary to add a large amount of flame retardants to the base material, which not only affects the foaming ratio and lightweight characteristics of the material, but also has an adverse effect on the uniformity and thermal insulation properties of the foam cells. At the same time, due to the uneven distribution of the added flame retardant in the material, the flame retardant properties may be limited to the surface layer, and an effective flame retardant structure cannot be formed inside, further limiting the comprehensive performance of the material. In addition, these added flame retardants may migrate during use, resulting in a decrease in the flame retardant effect, thereby affecting the long-term stability of the material.

[0006] Another significant shortcoming of the existing technology is the lack of methods for intrinsic optimization of the base material from a molecular structure perspective. Most flame retardant solutions rely mainly on external fillers, and fail to improve the flame retardancy and foaming performance synergy of the base material through molecular-level modification. This filler-based modification method makes it difficult to simultaneously improve the flame retardancy, mechanical properties, and foaming ratio of the material, and the comprehensive performance is difficult to meet the actual needs of multiple fields. In addition, when used in high temperature or humid heat environments, the thermal stability and thermal insulation properties of traditional flame retardant foam materials often perform poorly, further limiting their scope of application.

[0007] Therefore, the present invention proposes an ultra-light flame-retardant rubber foam material and a preparation method and application thereof to solve the deficiencies of the prior art. Summary of the invention

[0008] In view of the deficiencies of the prior art, the present invention provides an ultra-light flame-retardant rubber foam material and its preparation method and application. By adopting a chemical grafting modification technology, nitrogen-containing hexahydroxymethyl melamine is introduced into the carboxyl nitrile rubber molecular chain, so that the material has excellent intrinsic flame retardant properties, thereby avoiding the reliance on a high proportion of external flame retardants in traditional technologies. At the same time, the modified structure of the material significantly improves the foaming ratio and the uniformity of the pores, ensuring that both lightweight and thermal insulation properties are taken into account. In addition, the present invention achieves a balance between the flame retardancy, foaming properties and mechanical properties of the material through the coordinated optimization of the molecular chain structure, overcoming the defect of deteriorated mechanical properties in the prior art.

[0009] To achieve the above object, the present invention is implemented by the following technical scheme: an ultra-light flame-retardant rubber foam material, calculated by mass, comprises the following components: Modified carboxyl nitrile rubber: 10-100 parts; Foaming agent: 10-100 parts; Foaming aid: 2-20 parts; Cross-linking agent: 1-9 parts; Flame retardant: 30-80 parts; Inorganic filler: 10-100 parts; Tackifying resin: 10-100 parts; Softener: 10-100 parts; The modified carboxylated nitrile rubber is prepared by chemically grafting carboxylated nitrile rubber and hexahydroxymethyl melamine under the action of a catalyst.

[0010] Preferably, the preparation method of the modified carboxylated nitrile rubber comprises the following steps: Dissolve carboxylated nitrile rubber with an acid value of 25-38 mgKOH / g in toluene solvent, with the amount of solvent being 2-5 times the mass of the rubber; After calculating the carboxyl content in the carboxylated nitrile rubber, an equimolar amount of hexamethylolmelamine is added, and 0.5-5 parts of anhydrous calcium chloride is added as a catalyst; Stir the reaction in a water bath at 80-90°C for 24 hours; The toluene solvent is removed by heating and evaporation to obtain modified carboxyl nitrile rubber.

[0011] Preferably, the foaming agent is azodicarbonamide, sodium bicarbonate or a combination of the two, and the compounding ratio is 1:1-3:1.

[0012] Preferably, the flame retardant is a compound of aluminum hydroxide, magnesium hydroxide and ammonium polyphosphate, and the compounding ratio is 1:1:2.

[0013] Preferably, the inorganic filler is one or more of talc, calcium carbonate or silicon dioxide, and the particle size of the filler is 1-10 μm.

[0014] Preferably, the tackifying resin is phenolic resin, petroleum resin or C5 petroleum resin.

[0015] Preferably, a method for preparing an ultra-light flame-retardant rubber foam material comprises the following steps: Adding modified carboxyl nitrile rubber, foaming agent, foaming aid, crosslinking agent, flame retardant, inorganic filler, tackifying resin and softener into an internal mixer according to the formula ratio; Mix at 80-150℃ for 5-15 minutes; Pressing the kneaded mixture into a mold; The ultra-light flame-retardant rubber foam material is prepared by foaming at 160-180°C.

[0016] Preferably, the compression molding process uses a flat-plate vulcanizing press with a pressure controlled at 5-15 MPa for 5-20 minutes.

[0017] Preferably, the step of mixing the modified carboxylated nitrile rubber with the foaming agent, the foaming aid, the crosslinking agent and the flame retardant is completed in two steps, the first step is a banburying treatment, and the second step is an open mixing treatment, and the specific steps are as follows: Mixing treatment: Adding the modified carboxylated nitrile rubber, part of the inorganic filler, the tackifying resin and the softener into an internal mixer, and mixing at 80-120° C. for 5-10 minutes to obtain an initial mixture; Open refining process: Add the initial mixture, foaming agent, foaming aid, crosslinking agent, flame retardant and remaining inorganic filler into an open mill and mix at 50-80°C for 5-15 minutes until the mixture is uniform; Molding and Foaming: The mixture after the kneading is molded and then foamed at 160-180° C. to obtain an ultra-light flame-retardant rubber foam material.

[0018] Preferably, the ultra-light flame-retardant rubber foam material is used in building insulation, automobile interior decoration, cable sheathing or household appliance shock-absorbing pads.

[0019] The present invention provides an ultra-light flame-retardant rubber foam material and a preparation method and application thereof, which have the following beneficial effects: 1. The present invention adopts a grafting modification technology scheme of introducing hexahydroxymethyl melamine into the molecular chain of carboxyl nitrile rubber, thereby improving the intrinsic flame retardancy from the molecular structure and avoiding the negative influence of external flame retardants on foaming performance and density. Compared with the method of achieving flame retardant effect by adding a large amount of external flame retardants or halogen-containing flame retardants in the prior art, the present invention effectively solves the problems of material flammability, environmental pollution and excessive density of products, and provides a new way for lightweight and environmentally friendly flame retardant foam materials.

[0020] 2. The present invention optimizes the ratio of the foaming agent to the foaming aid and combines the uniform dispersion of the modified rubber to achieve the preparation of high-ratio foaming and low-density foam materials, which significantly improves the lightweight characteristics of the material. Different from the problems of uneven pore structure and limited foaming ratio due to excessively high ratios of fillers and flame retardants in the prior art, the present invention overcomes the defects of high density and high material use cost of traditional flame retardant materials while maintaining the foaming ratio, and meets the needs of both high performance and low cost.

[0021] 3. The present invention adopts a technical solution of synergistic optimization of closed-cell foam structure and flame retardancy within the molecular chain, so that the material has high-efficiency thermal insulation performance while maintaining a low thermal conductivity. Through the uniform distribution of the molecular-level flame retardant network, the material exhibits good thermal stability in a high-temperature environment. Compared with the phenomenon that traditional flame retardant materials have reduced thermal insulation effect and thermal stability due to uneven pore distribution or surface migration of flame retardants, the present invention effectively solves the problem of difficulty in maintaining thermal insulation performance during long-term high-temperature use, and significantly expands the application value of the material in the fields of building insulation and automotive interior.

[0022] 4. The present invention combines the optimization of the cross-linking agent ratio with the uniform distribution of the filler, and through the scientific regulation of the mechanical properties and the pore structure, improves the compressive strength, rebound performance and fatigue resistance of the material, and exhibits excellent aging stability. The stability of the material performance in a hot and humid environment is far better than that of traditional unmodified rubber materials. Compared with the foam materials in the prior art with weak mechanical properties and obvious degradation of aging performance, the present invention solves the bottleneck problem of insufficient mechanical properties and long-term use stability, and provides a reliable guarantee for the use of cable sheaths, shock-absorbing pads and other high-performance scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the preparation method of ultra-light flame-retardant rubber foam material. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Please see attached Figure 1 : Embodiment 1: Preparation of modified rubber 100g of carboxylated nitrile rubber with an acid value of 25mgKOH / g is dissolved in 400g of toluene solvent (the amount of solvent is 4 times the mass of the rubber).

[0026] An equal molar amount of hexahydroxymethylmelamine was added according to the carboxyl content, and 1 g of anhydrous calcium chloride was added as a catalyst.

[0027] The reaction was stirred in a water bath at 80°C for 24 hours.

[0028] The toluene solvent is removed by heating and evaporation to obtain carboxylated nitrile rubber modified with hexahydroxymethylmelamine.

[0029] Preparation of foaming materials formula: Modified carboxyl nitrile rubber: 100 parts; Azodicarbonamide and sodium bicarbonate (mixing ratio 1:1): 50 parts; Foaming aid (zinc stearate): 5 parts; Cross-linking agent (BIPB): 5 parts; Flame retardant (aluminum hydroxide, magnesium hydroxide and ammonium polyphosphate, compounding ratio 1:1:2): 60 parts; Talc (particle size 5 μm): 20 parts; Phenolic resin: 30 parts; Paraffin oil: 30 parts.

[0030] Mixing process: Mixing treatment: adding the modified carboxylated nitrile rubber, part of the inorganic filler (10 parts of talc), phenolic resin (15 parts), and paraffin oil (15 parts) into a mixer, mixing at 100°C for 10 minutes to obtain an initial mixture; Open mixing treatment: add the initial mixture, foaming agent, foaming aid, cross-linking agent, flame retardant and remaining inorganic filler into an open mixing mill, mix at 70°C for 10 minutes and mix evenly.

[0031] Compression Molding and Foaming: The mixture was added to a flat vulcanizing machine for compression molding, with the pressure controlled at 10 MPa for 10 minutes; The molded material was foamed at 170° C. for 15 minutes to obtain an ultra-light flame-retardant rubber foam material.

[0032] Embodiment 2: Preparation of modified rubber Same as Example 1, but using carboxylated nitrile rubber with an acid value of 28 mgKOH / g and 2 g of anhydrous calcium chloride.

[0033] Preparation of foaming materials formula: Modified carboxyl nitrile rubber: 100 parts; Azodicarbonamide and sodium bicarbonate (mixing ratio 2:1): 60 parts; Foaming aid: 10 parts; Cross-linking agent (DCP): 7 parts; Flame retardant (compound ratio is 1:2:2): 70 parts; Talc and calcium carbonate (mixing ratio 1:1, particle size 5μm): 30 parts; Petroleum resin: 20 parts; Paraffin oil: 40 parts.

[0034] Mixing process: Mixing treatment: Mixing at 120℃ for 10 minutes; Open refining treatment: open refining at 60℃ for 15 minutes.

[0035] Compression molding and foaming: Same as Example 1.

[0036] Embodiment 3: Preparation of modified rubber Same as Example 1, but using carboxylated nitrile rubber with an acid value of 29 mgKOH / g and 3 g of anhydrous calcium chloride.

[0037] Preparation of foaming materials formula: Modified carboxyl nitrile rubber: 100 parts; Azodicarbonamide and sodium bicarbonate (mixing ratio 1:1): 70 parts; Foaming aid: 6 parts; Cross-linking agent (BIPB): 4 parts; Flame retardant (compound ratio is 1:1:2): 50 parts; Talc: 15 parts; Phenolic resin: 25 parts; Paraffin oil: 20 parts.

[0038] Compression molding and foaming: pressure is 8MPa, foaming time is 12 minutes.

[0039] Comparative Example 1: Preparation of modified rubber Unmodified nitrile rubber (without carboxyl group) was used. 100 g of nitrile rubber was dissolved in 400 g of toluene solvent without adding hexahydroxymethylmelamine or anhydrous calcium chloride. Other operations were the same as those in Example 1.

[0040] Preparation of foaming materials The recipe is the same as in Example 1.

[0041] Comparative Example 2: Preparation of modified rubber The modification method is the same as that in Example 1.

[0042] Preparation of foaming materials formula: Modified carboxyl nitrile rubber: 100 parts; Azodicarbonamide: 50 parts; Foaming aid: 5 parts; Cross-linking agent: 5 parts; Flame retardant (ammonium polyphosphate): 100 parts; Talc: 20 parts; Petroleum resin: 30 parts; Paraffin oil: 30 parts.

[0043] Test experiment: Experimental Materials Example samples: The ultra-light flame-retardant rubber foam materials of Example 1, Example 2 and Example 3 are tailored to specifications according to experimental requirements.

[0044] Comparative sample: The materials of Comparative Examples 1 and 2 have the same specifications.

[0045] Main equipment: Thermal conductivity measuring instrument: LaserCompFOX50; Universal mechanical testing machine: Instron3365; UL-94 vertical burning tester; Constant temperature aging box; Laser scanning confocal microscopy (to observe the microstructure of materials); Infrared thermal imager (dynamic monitoring of thermal insulation performance).

[0046] Experimental environment: temperature 25±2℃, humidity 50±5%.

[0047] Experimental steps and procedures Comprehensive test of expansion ratio, density and flame retardant performance: Objective: To test the lightweight (expansion ratio and density) and flame retardant ability of the material at the same time, and verify the synergistic effect of the multi-performance of the material. Experimental method: Foaming ratio and density: The sample was cut into 100mm×100mm×10mm, and the length, width, thickness were measured before foaming, and the volume was calculated; After foaming, measure the sample volume and mass, and calculate the foaming ratio and density according to the formula: Foaming ratio = volume after foaming / volume before foaming; Density = mass / volume after foaming.

[0048] Flame retardant properties: Sample size: According to UL-94 vertical burning method, cut to 127mm×12.7mm×10mm; Test process: Hang the sample vertically, observe the self-extinguishing time after burning for 5 seconds, and record the dripping situation; Determine the flame retardancy level (V0, V1 or V2).

[0049] Thermal conductivity, thermal insulation and thermal stability testing: Objective: To test the thermal insulation and dynamic thermal stability of the material to verify its application potential in building insulation and automotive interior.

[0050] Experimental methods: Thermal conductivity test: The sample was cut into 200mm×200mm×20mm; Use a thermal conductivity meter to test the thermal conductivity in the range of 20-100°C and analyze the temperature dependence of the material.

[0051] Thermal insulation performance test: Fix the sample to the thermal insulation test device and install a thermocouple on the back; The high temperature box was set at a constant temperature of 100°C, and an infrared thermal imager was used to monitor the dynamic changes in the temperature of the back side of the sample and record the time required for the back side to heat up to 30°C.

[0052] Thermal stability test: Using a thermogravimetric analyzer (TGA), the sample was heated in an air atmosphere (30-800°C, heating rate 10°C / min) to analyze the thermal decomposition temperature and thermal stability of the material.

[0053] Comprehensive mechanical properties test: compression performance, resilience and fatigue performance Objective: Comprehensively evaluate the mechanical properties of the material and verify its suitability for use in shock absorbers and interior parts.

[0054] Experimental methods: Compression performance: The sample size is 50mm×50mm×10mm; Test the compressive strength under 50% compression deformation on a universal mechanical testing machine and record the force-displacement curve; Rebound performance: After 100% compression release, measure the sample thickness rebound rate: Rebound rate = (thickness after compression release / initial thickness) × 100%; Fatigue performance: After the samples were subjected to compression-release cycles (0%-50% compression deformation, frequency of 1 Hz, and 1000 cycles), their residual thickness ratio and changes in mechanical properties were tested.

[0055] Aging resistance and microstructure testing: Objective: To verify the long-term stability and durability of the material, and to reveal the mechanism of performance changes through microstructure observation.

[0056] Experimental methods: Aging resistance test: After the samples were placed in an aging box (70°C, 70% humidity) for 168 hours, the change rates of density, compressive strength and flame retardant properties were tested.

[0057] Microstructure testing: Laser scanning confocal microscopy was used to observe the pore morphology and distribution of the material before and after aging, and the effect of aging on the material microstructure was analyzed.

[0058] Experimental data: Table 1: Comprehensive performance test results The experimental results clearly show that the example materials have achieved comprehensive optimization in terms of foaming ratio, lightweight and flame retardant properties. Through the nitrogen element structure introduced into the molecular chain, the material has excellent intrinsic flame retardancy and can reach UL-94V0 level without the need for a large amount of added flame retardants. This modified structure is evenly distributed in the matrix, which improves the foaming performance of the material while maintaining a low density. Due to the lack of modified structure, the flame retardancy and foaming ratio of Comparative Example 1 are seriously insufficient, and although there is improvement in Comparative Example 2, the addition of flame retardants leads to an increase in density, which inhibits the realization of lightweight.

[0059] The tests of thermal insulation and thermal conductivity reveal the key role of closed-cell structure. The high-ratio foaming of the example material forms uniform closed pores, significantly reducing the continuity of the heat conduction path, and the thermal insulation effect is better than that of the comparative example. In addition, the example sample shows a higher thermal decomposition temperature in the dynamic thermal stability test, reflecting the improvement of high temperature resistance by molecular chain modification.

[0060] Mechanical property tests further illustrate the advantages of modified rubber. The example material not only performs well in compression strength, but also shows excellent recovery ability in resilience and fatigue performance tests. Its evenly distributed fillers and optimized molecular cross-linking structure can effectively disperse stress during use and extend the life of the material. However, the uneven pore distribution and filler aggregation problems of the comparative material significantly limit its application.

[0061] Through this series of experiments, the comprehensive technical effects of the present invention have been fully verified from foaming, flame retardancy, heat insulation to mechanical properties. The versatility and stability of the material are obviously superior to the existing technology, reflecting the potential for wide application in the fields of building insulation, automotive interior and so on.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-light flame-retardant rubber foam material, characterized in that: In parts by mass, it includes the following components: Modified carboxyl nitrile rubber: 10-100 parts; Foaming agent: 10-100 parts; Foaming aid: 2-20 parts; Cross-linking agent: 1-9 parts; Flame retardant: 30-80 parts; Inorganic filler: 10-100 parts; Tackifying resin: 10-100 parts; Softener: 10-100 parts; The modified carboxylated nitrile rubber is prepared by chemically grafting carboxylated nitrile rubber and hexahydroxymethyl melamine under the action of a catalyst.

2. The ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The preparation method of the modified carboxyl nitrile rubber comprises the following steps: Dissolve carboxylated nitrile rubber with an acid value of 25-38 mgKOH / g in toluene solvent, with the amount of solvent being 2-5 times the mass of the rubber; After calculating the carboxyl content in the carboxylated nitrile rubber, an equimolar amount of hexamethylolmelamine is added, and 0.5-5 parts of anhydrous calcium chloride is added as a catalyst; Stir the reaction in a water bath at 80-90°C for 24 hours; The toluene solvent is removed by heating and evaporation to obtain modified carboxyl nitrile rubber.

3. The ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The foaming agent is azodicarbonamide, sodium bicarbonate or a mixture of the two, and the mixture ratio is 1:1-3:

1.

4. The ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The flame retardant is a compound of aluminum hydroxide, magnesium hydroxide and ammonium polyphosphate, and the compounding ratio is 1:1:

2.

5. The ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The inorganic filler is one or more of talc, calcium carbonate or silicon dioxide, and the particle size of the filler is 1-10 μm.

6. The ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The tackifying resin is phenolic resin, petroleum resin or C5 petroleum resin.

7. A method for preparing an ultra-light flame-retardant rubber foam material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Adding modified carboxyl nitrile rubber, foaming agent, foaming aid, crosslinking agent, flame retardant, inorganic filler, tackifying resin and softener into an internal mixer according to the formula ratio; Mix at 80-150℃ for 5-15 minutes; Pressing the kneaded mixture into a mold; The ultra-light flame-retardant rubber foam material is prepared by foaming at 160-180°C.

8. The method for preparing an ultra-light flame-retardant rubber foam material according to claim 7, characterized in that: The compression molding process uses a flat plate vulcanizer, the pressure is controlled at 5-15 MPa, and the time is 5-20 minutes.

9. The method for preparing an ultra-light flame-retardant rubber foam material according to claim 1, characterized in that: The step of mixing the modified carboxylated nitrile rubber with the foaming agent, the foaming aid, the crosslinking agent and the flame retardant is completed in two steps, the first step is a banburying treatment, and the second step is an open mixing treatment, and the specific steps are as follows: Mixing treatment: Adding the modified carboxylated nitrile rubber, part of the inorganic filler, the tackifying resin and the softener into an internal mixer, and mixing at 80-120° C. for 5-10 minutes to obtain an initial mixture; Open refining process: Add the initial mixture, foaming agent, foaming aid, crosslinking agent, flame retardant and remaining inorganic filler into an open mill and mix at 50-80°C for 5-15 minutes until the mixture is uniform; Molding and Foaming: The mixture after the kneading is molded and then foamed at 160-180° C. to obtain an ultra-light flame-retardant rubber foam material.

10. Application of the ultra-light flame-retardant rubber foam material according to claims 1-6 in building insulation, automobile interior decoration, cable sheathing or shock-absorbing pads for household appliances.

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