Flame-retardant rubber foaming material as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant rubber foam material and a preparation method and application thereof, and relates to the technical field of rubber foaming, the flame-retardant rubber foam material comprises the following components by mass: 100 parts of a rubber matrix, 0-10 parts of a compatibilizer, 5-10 parts of carbon black (CB), 20-40 parts of diethyl aluminum hypophosphite (ADP), 20-40 parts of piperazine pyrophosphate (PAPP), 5-20 parts of expandable graphite (EG), 0-4 parts of a conductive nano filler, and 2-10 parts of a plasticizer. 1.5-3 parts of a vulcanizing agent and 2-7 parts of an accelerant. The rubber-based compound flame-retardant system combines a plurality of additives, provides excellent flame retardance and conductivity, and is suitable for an intelligent fire alarm system. The material can be applied to fire-fighting shoes and clothes according to foaming density, energy is supplied through the triboelectric effect, and safety is enhanced. The material has the characteristics of light weight, heat insulation, flexibility and the like, and provides an innovative scheme for fireproof and energy-saving projects.

Description

Technical Field

[0001] The invention relates to the technical field of rubber foaming, and in particular to a flame retardant rubber foaming material and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern industry, the application of materials in various fields is becoming more and more extensive. Especially in high-end industrial fields such as construction, automobiles, and aerospace, lightweight and high-performance flame-retardant materials are widely used. As an environmentally friendly and chemically residue-free foaming method, supercritical foaming technology has become an effective means to prepare various functional foam materials with its green and sustainable advantages. Foams made of rubber as the base material have been widely used due to their excellent thermal insulation properties. Rubber foam not only has good thermal insulation and durability, but also can adapt to harsh temperature and environmental changes, and is used in many fields such as construction, automobiles, and aerospace. Although EPDM foam has outstanding performance in thermal insulation, as a polymer material, it is still prone to combustion reactions under high temperature or combustion conditions, which limits its wide application in some fields with high safety requirements. Therefore, it is urgent to develop rubber foam materials with excellent flame retardant properties to solve its flammability problem in high temperature environments, so as to meet increasingly stringent industrial safety requirements.

[0003] At present, in order to improve the flame retardant properties of rubber foam materials, researchers have explored a variety of different flame retardant technologies, the most common of which is to add flame retardants to the polymer matrix. This method is more durable and stable than the flame retardant effect that relies on surface coatings, and can ensure that the material still has good flame retardant properties when the surface is damaged. Traditional inorganic flame retardants (such as aluminum hydroxide, expanded graphite, etc.) are often used for flame retardant treatment of polymer materials, but they have poor compatibility, limited flame retardant effects, and some types of flame retardants may release harmful gases at high temperatures, posing certain safety hazards. Compared with inorganic flame retardants, intumescent flame retardant systems have gradually gained favor due to their good compatibility with polymers. In addition, intumescent flame retardants can expand into gas during heating to form a thermal isolation layer, thereby further enhancing the flame retardancy of the material. However, even so, a single type of flame retardant is often difficult to meet the multiple safety requirements in complex application environments. Therefore, it is necessary to explore a combination of multiple flame retardant technologies to improve the comprehensive flame retardant ability of the material.

[0004] Although current flame retardant technologies have solved the fire protection problem of materials to a certain extent, these technologies still have some shortcomings, especially in meeting the needs of high performance and multi-function. First, existing flame retardant materials often ignore the early warning function of materials in fire. Traditional intelligent fire alarm systems rely on batteries or power grids, which makes the system unable to work properly in the event of power outages or battery failures, reducing its reliability in emergency situations. In addition, current IFAS are usually unable to effectively alarm in the early stages of fire, and the duration of the alarm is also short, resulting in firefighters and other personnel not being able to get enough time to evacuate or deal with the fire. On the other hand, although many studies have introduced conductive materials such as expanded graphite and carbon nanotubes into foams to enhance their fire alarm performance, these materials may break or degrade under high temperature or flame attack, and cannot ensure continuous and reliable operation in extreme fire environments. At the same time, how to effectively combine triboelectric properties with flame retardant properties to develop a self-powered system that can provide early warning functions in fires and work stably for a long time without relying on external power sources is still a technical problem that needs to be solved urgently. Therefore, a new solution is urgently needed to meet the high standards of modern fire safety. Summary of the invention

[0005] In order to achieve the above-mentioned purpose of the invention and to solve the above-mentioned technical problems, the present invention provides a flame-retardant rubber foam material, comprising the following components in parts by mass:

[0006] Rubber base 100 parts

[0007] Compatibility agent 0-10 parts

[0008] Carbon black (CB) 5-10 parts,

[0009] 20-40 parts of diethylaluminum hypophosphite (ADP),

[0010] Piperazine pyrophosphate (PAPP) 20-40 parts,

[0011] Expandable graphite (EG) 5-20 parts,

[0012] Conductive nanofiller 0-4 parts,

[0013] Plasticizer 2-10 parts,

[0014] 1.5-3 parts of vulcanizing agent,

[0015] 2-7 parts of accelerator.

[0016] Preferably, the rubber matrix is ​​one or more combinations of EPDM, EVM and CPE.

[0017] Preferably, the conductive nanofiller is graphene or carbon nanotube (CNT).

[0018] Preferably, the plasticizer is one or more of paraffin oil and dioctyl terephthalate.

[0019] Preferably, the vulcanizing agent is any one of di-tert-butyl cumene peroxide (BIPB), dicumyl peroxide DCP, and sulfur.

[0020] Preferably, the accelerator is one or more of triallyl isocyanurate (TAIC), zinc oxide, and stearic acid.

[0021] Preferably, the solubilizing agent is maleic anhydride grafted EVA (EVA-g-GMA) or maleic anhydride grafted CPE (CPE-g-GMA).

[0022] The present invention also provides a method for preparing the flame retardant rubber foam material, comprising the following steps:

[0023] S1 Preparation of rubber composite material: set the temperature of internal mixer to 80-120℃, add 100 parts of rubber matrix, mix for 2-4min, and after the torque is stable, add 20-40 parts of diethyl aluminum hypophosphite, 20-40 parts of piperazine pyrophosphate, 5-20 parts of expandable graphite, 0-4 parts of conductive nanofiller, 2-10 parts of plasticizer, 5-10 parts of carbon black in sequence to obtain masterbatch, then add accelerator, mix for 1-3min, add vulcanizer, mix for 1-3min, discharge, and obtain final rubber;

[0024] S2: Forming the rubber composite material: placing the final rubber mixture in a flat vulcanizer for vulcanization to obtain a rubber composite material sample;

[0025] S3 Preparation of rubber composite foaming material: The rubber composite material sample is then placed in a supercritical foaming reactor and heated to 400 °C with N 2 , CO 2 Or the mixed gas of the two is saturated, and then the pressure is quickly released to obtain a foamed material; the foamed material is placed in a flat vulcanizer to complete shaping to obtain the desired flame-retardant rubber foamed material.

[0026] Preferably, in step S2, the vulcanization temperature is 140-160° C., and the vulcanization time is 4-15 min.

[0027] Preferably, in step S3, the saturation time is 2-4 hours, the saturation pressure is 20-30 MPa, the setting temperature is 150-170° C., and the setting time is 10-30 minutes.

[0028] The present invention also provides an application of the flame-retardant rubber foam material in fire safety equipment, emergency rescue equipment or fire protection products.

[0029] The technical solution provided by the present invention brings beneficial effects:

[0030] (1) A flame retardant system of diethyl aluminum hypophosphite, piperazine pyrophosphate and expandable graphite is added to the rubber matrix. Through the synergistic effect of the flame retardant compound, a rubber foam material with both light weight and high flame retardancy is obtained. At the same time, the expansion-conductivity characteristics of expandable graphite are utilized. This material can be used in intelligent fire alarms with a response time of less than 40s. In order to further improve its response time in the fire alarm system, conductive nanofillers are introduced into the system to make the response time less than 10s, while not reducing its flame retardant properties, thereby obtaining a fire alarm system with high sensitivity, long alarm duration and low cost.

[0031] (2) This material can be precisely controlled by adjusting the foaming conditions to achieve different application scenarios. 3 When the density is about 0.2g / cm3, it can be used in the outsole of fire shoes. This material has triboelectric properties. When firefighters are working, pressure and friction are generated when walking, which generates electrical signals. When the electrical signals are interrupted or abnormal, rescue is required. When the density is about 0.2g / cm3, it can be connected with wires to make fire alarms and put them into the interlayer of fire suits. The friction between the flame retardant foam and the clothes during the exercise of firefighters generates electricity to supply energy to the system. At the same time, when the surface temperature of the fire suit reaches the critical value, a conductive path can be formed to remind firefighters to lower the temperature of the fire suit in time to avoid burns, thereby protecting the safety of firefighters.

[0032] (3) This material not only has active and passive fire protection functions, but also has the characteristics of light weight, heat insulation, flexibility, and high resistance to flame impact, providing a new choice for energy-saving projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the SEM image of Example 1 of the present invention.

[0034] Figure 2 This is the SEM image of Example 2 of the present invention.

[0035] Figure 3 This is the SEM image of Example 3 of the present invention.

[0036] Figure 4 This is the SEM image of Comparative Example 1 of the present invention.

[0037] Figure 5 This is the SEM image of Comparative Example 2 of the present invention.

[0038] Figure 6 This is the SEM image of Comparative Example 3 of the present invention.

[0039] Figure 7The cone calorimeter test photos of the embodiments of the present invention and the comparative examples are shown in FIG.

[0040] Figure 8 The following are photos of carbon residues after cone calorimeter testing of the embodiments of the present invention and the comparative example.

[0041] Fig. 9 These are photos of the test process and response time of the intelligent fire alarm system according to an embodiment of the present invention.

[0042] Fig.10 It is the infrared spectrum of CPE-g-GMA of the present invention.

[0043] Fig.11 This is the human motion energy harvesting system of Example 7 of the present invention, wherein a is the change of current and b is the change of voltage, c is the circulating current, and d is a schematic diagram of the intelligent protective clothing safety system. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0045] Example 1

[0046] A flame retardant rubber foam material, comprising the following components in parts by mass:

[0047] EPDM 100 parts

[0048] Carbon black (CB) 10 parts,

[0049] 30 parts of diethylaluminum hypophosphite (ADP),

[0050] 30 parts of piperazine pyrophosphate (PAPP),

[0051] Expandable graphite (EG) 20 parts,

[0052] 10 parts of paraffin oil,

[0053] 2 parts of di-tert-butyl peroxide isopropylbenzene (BIPB),

[0054] Triallyl isocyanurate (TAIC) 2 parts.

[0055] The method for preparing a flame retardant rubber foam material comprises the following steps:

[0056] Preparation of S1 rubber composite material: set the temperature of the internal mixer to 110°C, add EPDM, mix for 2 minutes, and after the torque is stable, add diethyl aluminum hypophosphite, piperazine pyrophosphate, expandable graphite, paraffin oil, and carbon black in sequence to obtain a masterbatch, then add triallyl isocyanurate, mix for 3 minutes, add di-tert-butyl peroxide isopropylbenzene, mix for 1 minute, discharge, and obtain the final rubber;

[0057] S2: Forming of rubber composite material: placing the final rubber mixture in a flat vulcanizer for vulcanization at a vulcanization temperature of 160° C. for a vulcanization time of 15 min to obtain a rubber composite material sample;

[0058] S3 Preparation of rubber composite foaming material: The rubber composite material sample is then placed in a supercritical foaming reactor at 100°C and heated to 400°C with N 2 Saturate for 2 hours at a pressure of 20 MPa, then quickly release the pressure to obtain a foamed material; put the foamed material into a flat vulcanizer at 170°C (setting temperature is 150-170°C) for 10 minutes to complete setting to obtain the desired flame-retardant rubber foamed material.

[0059] Example 2

[0060] A flame retardant rubber foam material, comprising the following components in parts by mass:

[0061] EPDM 100 parts

[0062] Carbon black (CB) 10 parts,

[0063] 28 parts of diethylaluminum hypophosphite (ADP),

[0064] Piperazine pyrophosphate (PAPP) 28 parts,

[0065] Expandable graphite (EG) 20 parts,

[0066] 4 parts of carbon nanotubes (CNT),

[0067] 10 parts of paraffin oil,

[0068] 2 parts of di-tert-butyl peroxide isopropylbenzene (BIPB),

[0069] Triallyl isocyanurate (TAIC) 2 parts.

[0070] The method for preparing a flame retardant rubber foam material comprises the following steps:

[0071] Preparation of S1 rubber composite material: set the temperature of the internal mixer to 110℃, add EPDM, mix for 2min, and after the torque is stable, add diethyl aluminum hypophosphite, piperazine pyrophosphate, expandable graphite, carbon nanotubes, paraffin oil, carbon black in sequence to obtain a masterbatch, then add triallyl isocyanurate, mix for 3min, add di-tert-butyl peroxide isopropylbenzene, mix for 1min, discharge, and obtain the final rubber;

[0072] S2: Forming of rubber composite material: placing the final rubber mixture in a flat vulcanizer for vulcanization at a vulcanization temperature of 160° C. for a vulcanization time of 15 min to obtain a rubber composite material sample;

[0073] Preparation of S3 rubber composite foaming material: then put the rubber composite material sample into a supercritical foaming kettle at 100°C and saturate it with N2 for 2h, with a pressure of 20MPa, and then quickly release the pressure to obtain a foaming material; put the foaming material into a flat vulcanizer at 170°C (setting temperature is 150-170°C) for 10min to complete the setting, and obtain the required flame-retardant rubber foaming material.

[0074] Example 3

[0075] The preparation method is the same as that in Example 2, except that the amount of carbon black is 5 parts, the amount of diethylaluminum hypophosphite is 35 parts, the amount of piperazine pyrophosphate is 35 parts, the amount of expandable graphite is 10 parts, the conductive nanofiller is graphene, the amount is 2 parts, the plasticizer is dioctyl terephthalate DOP, the amount is 2 parts, and the vulcanizing agent is diisopropyl peroxide DCP, the amount is 3 parts.

[0076] Example 4

[0077] The preparation method is the same as that in Example 2, except that the rubber matrix is ​​CPE, the amount of carbon black is 10 parts, the amount of diethyl aluminum hypophosphite is 20 parts, the amount of piperazine pyrophosphate is 20 parts, the amount of expandable graphite is 5 parts, the amount of dioctyl terephthalate DOP is 8 parts, and the amount of diisopropylbenzene peroxide DCP is 1.5 parts; the vulcanization temperature in step S2 is 150°C, and the vulcanization time is 10 min; the foaming gas in step S3 is N 2 and CO 2 Mixed gas, pressure 2Mpa CO 2 +18MPa N 2 , the foaming temperature is 110℃ and the saturation time is 1.5h.

[0078] Example 5

[0079] A flame retardant rubber foam material, comprising the following components in parts by mass:

[0080] EPDM / EVM 100 parts, mass ratio is 50:50,

[0081] Compatibilizer EVA-g-GMA 5 parts,

[0082] Carbon black (CB) 10 parts,

[0083] 28 parts of diethylaluminum hypophosphite (ADP),

[0084] Piperazine pyrophosphate (PAPP) 28 parts,

[0085] Expandable graphite (EG) 20 parts,

[0086] 4 parts of carbon nanotubes (CNT),

[0087] 10 parts of paraffin oil,

[0088] Curing agent: 1 part of di-tert-butyl peroxide isopropylbenzene (BIPB), 1 part of sulfur,

[0089] Accelerator triallyl isocyanurate (TAIC) 1 part, stearic acid (SA) 1 part, zinc oxide (ZnO) 5 parts.

[0090] The method for preparing a flame retardant rubber foam material comprises the following steps:

[0091] Preparation of S1 rubber composite material: set the temperature of the internal mixer to 120°C, add EPDM, EVM and EVA-g-GMA, mix for 4 minutes, and after the torque is stable, add diethyl aluminum hypophosphite, piperazine pyrophosphate, expandable graphite, carbon nanotubes, paraffin oil, carbon black in sequence to obtain a masterbatch, then add triallyl isocyanurate, mix for 3 minutes, add di-tert-butyl peroxide isopropylbenzene, mix for 1 minute, discharge, and obtain the final rubber;

[0092] S2: Forming of rubber composite material: placing the final rubber mixture in a flat vulcanizer for vulcanization at a vulcanization temperature of 170° C. for a vulcanization time of 2 min to obtain a rubber composite material sample;

[0093] S3 Preparation of rubber composite foaming material: The rubber composite material sample is then placed in a supercritical foaming reactor at 80°C and heated with N 2 Saturated for 2 hours, the pressure is 25 MPa, and then the pressure is quickly released to obtain a foamed material; the foamed material is placed in a 150°C flat vulcanizer for 30 minutes to complete shaping, and the desired flame-retardant rubber foamed material is obtained. EVA-g-GMA is commercially available.

[0094] Example 6

[0095] The preparation method is the same as that of Example 5, except that the rubber matrix is ​​EPDM / CPE, the mass ratio is 30:60, the compatibilizer is CPE-g-GMA, the amount is 10 parts, diethyl aluminum hypophosphite (ADP) is 30 parts, piperazine pyrophosphate is 30 parts, expandable graphite (EG) is 18 parts, graphene is 2 parts, the plasticizer is DOP, the amount is 10 parts, the accelerator is triallyl isocyanurate (TAIC), the amount is 2 parts, the vulcanizing agent is di-tert-butyl peroxide isopropylbenzene (BIPB), the amount is 2 parts; in step S2, the vulcanization temperature is 155° C., and the vulcanization time is 6 min; in step S3, the foaming gas is N 2 , pressure is 30MPa, foaming temperature is 130℃, saturation time is 4h. CPE-g-GMA is homemade, and the preparation method is: CPE is melt-grafted with modified monomer GMA and initiator BPO, the experimental temperature is 120℃, the rotation speed is 60r / min, and the reaction time is 10min.

[0096] Example 7

[0097] The preparation method is the same as that of Example 2, except that the rubber matrix is ​​EPDM / CPE, the mass ratio is 30:60, the compatibilizer is CPE-g-GMA, the amount is 10 parts, the carbon nanotubes are 3 parts, the plasticizer is paraffin oil, the amount is 6 parts, the accelerator is triallyl isocyanurate (TAIC), the amount is 2 parts, the vulcanizing agent is di-tert-butyl peroxide isopropylbenzene (BIPB), the amount is 2 parts; the vulcanization temperature in step S2 is 160°C, and the vulcanization time is 6 min; the foaming gas in step S3 is 10 MPa N 2 and 3MPa of mixed gas, the pressure is 3+10MPa, the foaming temperature is 100℃, and the saturation time is 2h. The sample is made into 2mm thick and close to the bottom of the shoe to become the outsole. The human body motion energy collection system is used to record the generated voltage and current signals.

[0098] Comparative Example 1

[0099] The same preparation method as in Example 2 was used for preparation, except that only the rubber matrix, 10 parts of carbon black, 10 parts of paraffin oil, and 10 parts of di-tert-butyl peroxide isopropylbenzene (BIPB) were added.

[0100] Comparative Example 2

[0101] The same preparation method as Comparative Example 1 was used, except that 80 parts of diethylaluminum hypophosphite were added.

[0102] Comparative Example 3

[0103] The same preparation method as that of Comparative Example 1 was used for the preparation, except that 40 parts of diethylaluminum hypophosphite and 40 parts of piperazine pyrophosphate were further added.

[0104] Experimental test:

[0105] 1. Tensile strength and tear strength test: Tested in accordance with national standards GB / T 528-2009 and GB / T 529-2008.

[0106] 2. Use scanning electron microscope (SEM JSM-7500F, ZEOL) to observe the microstructure of the brittle section of flame retardant foam.

[0107] 3. Oxygen index: refer to standard GB / T2406.2-2009

[0108] 3. Use cone calorimeter to test the total heat and total smoke of the material. The test standard is GB / T16172-2007. Sample size: 75*75*5mm, radiation power is 25kW / m2

[0109] 4. Flame alarm sensor test: Connect a sample with a size of 30×30×2mm to a 24V DC power supply and an alarm lamp to form a fire alarm circuit. Expose the sample to the flame of an alcohol lamp, with the distance between the bottom of the sample and the wick being about 15mm, and the size being 30*30*2mm. Record the fire alarm triggering time and resistance change. Use a precision resistance tester (MY60) to record the resistance.

[0110] 5. Triboelectric test: The samples were tested with an electrometer (Keithley 6514) at a pressure of 6N and a frequency of 4Hz. A human motion energy collection system was designed to test the shoes (the bottom of the shoes is made of flame-retardant foam material).

[0111] The friction is performed and the resulting voltage and current signals are recorded.

[0112] Table 1 Test data

[0113]

[0114] Note: Since the comparative sample is not conductive, there is no response time data.

[0115] contrast Figure 1-Figure 6 The cell sizes of different foams, Figure 4 The cell structure of the foam without flame retardant system. It can be seen that there is no flame retardant in the cell wall and between cells. The average cell size is about 50um and is evenly distributed. Figure 5 This is the cell structure of the foam with only ADP added. It can be seen that the ADP particles are larger and the cell size is uneven. Figure 6The pore structure of the foam in which part of PAPP replaces ADP. The introduction of PAPP makes the bimodal structure more obvious, and the average pore size is reduced. At the same time, due to the reduction of the total amount of ADP, the large particles are reduced. Expandable graphite is further introduced into the system to replace part of ADP and PAPP. It can be seen that when the total amount is the same, the number of large pores increases after the addition of expandable graphite ( Figure 1 ); after adding a small amount of conductive nanofillers with finer sizes, the pore size is reduced again.

[0116] Figure 7 , Figure 8 The flame retardant performance of Example 1 compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3. Figure 7 It can be seen that compared with Comparative Examples 1, 2 and 3, the addition of the composite flame retardant system in Example 1 significantly increases the oxygen index of the foam material. Figure 8 For example, in Comparative Example 1, no complete carbon layer was formed after combustion, and only residues were left; for Comparative Example 2, although the addition of ADP partially increased the amount of residual carbon, a complete carbon layer was still not formed. This is because although ADP has excellent gas-phase flame retardancy, it lacks carbon-forming ability, which results in a relatively weak carbon layer formed on the sample and cannot effectively resist flame erosion; for Comparative Example 3, when part of PAPP replaced ADP, the oxygen index of the foam did not increase significantly, but the heat and smoke generation decreased. This is because the addition of PAPP promoted the formation of a carbon layer on the sample surface. The carbon layer can serve as a physical barrier to effectively prevent the transfer of heat and combustible gases, thereby reducing heat release and smoke generation.

[0117] The compounding of the flame retardant system of ADP, PAPP and EG in Example 1 further improves the oxygen index of the foam material to >36%, reaching a high flame retardant level, and the expandable graphite in the compounded flame retardant system has expansion-conductivity characteristics when burning, and has a response time in the manufactured fire alarm, while the comparative examples 1-3 without adding expandable graphite do not have such a response. ADP in the compounded flame retardant system has excellent gas phase flame retardancy, and generates a large amount of free radical quencher after being heated and gasified, which inhibits the speed of flame erosion of the sample. PAPP has an excellent carbonization effect. Its addition causes the surface of the sample to be rapidly carbonized during combustion, thereby forming a solid and complete carbon layer, effectively preventing further erosion of the flame. The addition of expandable graphite makes the surface of the carbon layer covered with graphite worms, forming the skeleton of the carbon layer, while also maintaining a complete carbon layer structure, effectively resisting direct contact with the flame, and having expansion-conductivity characteristics. The compounding of the three can greatly weaken the degree of combustion of the sample.

[0118] In Example 2, conductive nanofillers are further added, which greatly reduces the response time during combustion, allowing the alarm to be triggered within 10 seconds, thereby improving the sensitivity of the intelligent fire alarm sensor.

[0119] Example 3 Compared with EPDM, EVM has better flame retardancy and lower smoke emission.

[0120] In Example 4, CPE has better flame retardancy than EPDM, but due to the presence of chlorine, the smoke generation is increased.

[0121] Compared with Example 2, Example 5 has the same filler dosage, but the vulcanization system process and foaming process are different. The filler system is related to functionality, while the vulcanization process and foaming process are related to the density of the material. Under the same filler system, replacing EPDM with part of EVM can obtain a higher oxygen index because EVM has better flame retardancy, which improves the flame retardancy of the mixed material.

[0122] In Example 6, compared with Example 1, CPE replaces part of EPDM in the matrix material, and in order to increase compatibility, GMA-CPE is added. The total amount of filler is the same, except that 2 parts of graphene replace 2 parts of expandable graphite. From the oxygen index point of view, the addition of CPE can significantly increase the oxygen index of the material, but at the same time, the introduction of Cl element will slightly increase the total smoke volume. At the same time, the introduction of graphene can also significantly shorten the response time.

[0123] Fig. 9 The outsole of the shoe was prepared according to Example 7, and friction was performed, and the voltage and current signals generated were recorded.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flame retardant rubber foam material, characterized in that: Contains the following components by mass: Rubber matrix 100 parts, Compatibilizer 0-10 parts, Carbon black 5-10 parts, 20-40 parts of diethyl aluminum hypophosphite, 20-40 parts of piperazine pyrophosphate, 5-20 parts expandable graphite, Conductive nanofiller 0-4 parts, Plasticizer 2-10 parts, 1.5-3 parts of vulcanizing agent, Accelerator 2-7 parts.

2. The flame retardant rubber foam material according to claim 1, characterized in that: The rubber matrix is ​​one or more combinations of EPDM, EVM and CPE.

3. The flame retardant rubber foam material according to claim 1, characterized in that: The conductive nanofiller is graphene or carbon nanotube.

4. The flame retardant rubber foam material according to claim 1, characterized in that: The plasticizer is one or more of paraffin oil and dioctyl terephthalate.

5. The flame retardant rubber foam material according to claim 1, characterized in that: The vulcanizing agent is any one of di-tert-butyl peroxide isopropylbenzene, diisopropylbenzene peroxide and sulfur, and the accelerator is one or more of triallyl isocyanurate, zinc oxide and stearic acid.

6. The flame retardant rubber foam material according to claim 1, characterized in that: The solubilizing agent is maleic anhydride grafted EVA or maleic anhydride grafted CPE.

7. A method for preparing the flame retardant rubber foam material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1 Preparation of rubber composite material: set the temperature of internal mixer to 80-120℃, add 100 parts of rubber matrix, mix for 2-4min, and after the torque is stable, add 20-40 parts of diethyl aluminum hypophosphite, 20-40 parts of piperazine pyrophosphate, 5-20 parts of expandable graphite, 0-4 parts of conductive nanofiller, 2-10 parts of plasticizer, 5-10 parts of carbon black in sequence to obtain masterbatch, then add accelerator, mix for 1-3min, add vulcanizer, mix for 1-3min, discharge, and obtain final rubber; S2: Forming the rubber composite material: placing the final rubber mixture in a flat vulcanizer for vulcanization to obtain a rubber composite material sample; S3 Preparation of rubber composite foaming material: then put the rubber composite material sample into a supercritical foaming kettle and saturate it with N2, CO2 or a mixture of the two gases, then quickly release the pressure to obtain a foaming material; put the foaming material into a flat vulcanizer to complete shaping to obtain the desired flame-retardant rubber foaming material.

8. The preparation method according to claim 7, characterized in that: In step S2, the vulcanization temperature is 140-160° C., and the vulcanization time is 4-15 minutes.

9. The preparation method according to claim 7, characterized in that: In the step S3, the saturation time is 2-4 hours, the saturation pressure is 20-30 MPa, the setting temperature is 150-170° C., and the setting time is 10-30 minutes.

10. Application of a flame retardant rubber foam material in fire safety equipment, emergency rescue equipment or fire protection products.

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