Fireproof flame-retardant ceramic ethylene propylene diene monomer power battery sealing ring material and preparation method thereof

Abstract

The invention belongs to the technical field of sealing ring material preparation, and particularly discloses a fireproof flame-retardant ceramic ethylene-propylene-diene monomer power battery sealing ring material and a preparation method of the sealing ring material. The ethylene propylene diene monomer composition is prepared from 25-60% of ethylene propylene diene monomer, 10-30% of inorganic filler, 1-5% of cross-linking substance, 5-10% of softening agent, 10-35% of fluxing agent and 10-35% The sealing ring material provided by the invention can be converted into self-supporting ceramic residues with certain strength when encountering high temperature caused by external fire disasters and the like, and the ceramic residues can prevent transmission of heat / oxygen, so that the material provided by the invention has more excellent fireproof and flame-retardant effects; and through optimization of formula types and dosage, the comprehensive performance of the material is good.

Description

Technical Field

[0001] This invention belongs to the field of sealing ring material preparation technology, specifically relating to a fire-retardant ceramicized EPDM rubber power battery sealing ring material and its preparation method. Background Technology

[0002] Battery safety issues seriously hinder the popularization and promotion of electric vehicles. In recent years, frequent electric vehicle battery fires have attracted significant public attention. There are many causes of battery fires, primarily overcharging, external short circuits, internal short circuits, over-discharge, and impacts or crushing. However, there is another major, often overlooked, hazard to battery safety: in the event of an external fire, some polymer materials used in battery packaging (such as battery seals) have poor fire resistance and flame retardancy, making them prone to combustion and potentially leading to battery explosions.

[0003] Ceramicizable polymers are a novel type of thermal protective ceramic material, completely different from traditional thermal protective materials. At room temperature, these materials exhibit the same processing performance as traditional polymer-based materials. However, at high temperatures, the polymer matrix and ceramicized powder undergo a series of reactions to form a ceramic layer. This prevents further polymer decomposition and volatilization loss, while simultaneously blocking external heat transfer within the material, thus protecting the internal components. Traditional polymer-based materials completely decompose under high-temperature, aerobic conditions. To improve the flame retardancy and fire resistance of polymers, halogenated flame retardants or large amounts of inorganic particle fillers are typically added during the molding and processing of polymer materials. However, halogenated flame retardants produce many harmful gases and fumes during combustion, limiting the application of traditional polymers in fire protection. Ceramicizable polymers, under high-temperature, aerobic conditions, produce low smoke and no toxic gases, providing a new direction for research on fire-resistant polymers. Research on fire-retardant materials has begun to shift from traditional polymers to "ceramicizable polymers." The matrix of most ceramizable polymer materials is silicone rubber. Due to the silicon-oxygen bonds inherent in silicone rubber, this material is relatively easy to form a ceramizable structure. However, the addition of a large amount of filler will reduce the mechanical properties of silicone rubber. Ceramizable materials, as a new type of material that can maintain self-support at high temperatures for a long time, gradually transform into a self-supporting ceramic body during combustion, thus maintaining the basic stability of the material's shape and size.

[0004] EPDM is inexpensive, has good elasticity, good heat aging resistance, excellent weather resistance, good electrical insulation, good resistance to chemical media, and good water resistance. Moreover, EPDM can accommodate a large amount of filler without reducing its mechanical properties. However, EPDM contains only carbon and hydrogen, making it easily combustible and leaving no residue after combustion. Compared to silicone rubber, EPDM is difficult to ceramicize. In recent years, research and application of EPDM ceramicization have made significant progress. In existing technology, patent CN109320852A discloses a ceramicized EPDM rubber material and its preparation method. After ceramicization, the EPDM material exhibits good fire resistance and high-temperature resistance. However, the formulation includes more than twenty raw materials, which poses significant challenges to production. Patent document CN117362847A discloses the preparation of ceramicized EPDM rubber flame-retardant products, with raw materials including EPDM rubber, zinc oxide, stearic acid, antioxidant, coupling agent, paraffin oil, reinforcing filler, oleamide, peroxide vulcanizing agent, ceramicized flame retardant, titanium dioxide, and iron oxide pigment. The ceramicized flame retardant in the formulation includes aluminum hydroxide, magnesium hydroxide, zinc borate, porous adsorbent, connecting fiber material, and compatibilizer raw materials. The ceramicized EPDM rubber is formed through the interaction of these various raw materials. Patent document CN 110982185A discloses the preparation of a fire-retardant sealing rubber material. The raw materials include the following components: rubber, vulcanizing agent, rubber reinforcing agent, silane coupling agent, flame retardant, synergistic flame retardant, charring agent, fluxing agent, and ceramic filler. This scheme reduces the amount of expandable graphite added as a flame retardant. Through the ceramicization of the rubber and synergistic flame retardancy, the fire-retardant sealing rubber material possesses good mechanical properties and excellent flame retardant performance.

[0005] In the aforementioned prior art, the overall performance of ceramicized EPDM rubber is difficult to guarantee. Therefore, this invention is proposed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a fire-retardant ceramicized EPDM power battery sealing ring material and its preparation method. By adding different fluxes with stepped melting temperatures, the ceramicization of EPDM is better achieved. By adding flame retardants to the material formulation, the flame retardants and ceramicized EPDM work synergistically, resulting in EPDM materials with superior fire-retardant effects and comprehensive performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a fire-retardant ceramicized EPDM rubber power battery sealing ring material, which is made of the following raw materials by weight: 25-60% EPDM rubber, 10-30% inorganic filler, 1-5% crosslinking substance, 5-10% softener, 10-35% fluxing agent, and 10-35% flame retardant.

[0009] As a preferred embodiment of the present invention, the density of the EPDM rubber is 900–960 g / cm³. 3 At 125°C, the Mooney viscosity is 55, and the vinyl content is 45%.

[0010] As a preferred embodiment of the technical solution of the present invention, the inorganic filler is selected from one or more of kaolin, talc, diatomaceous earth, sepiolite, montmorillonite, or mica.

[0011] As a preferred embodiment of the present invention, the crosslinking substance is composed of a crosslinking agent and a co-crosslinking agent; the crosslinking agent is selected from one or more of benzoyl peroxide, 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane or dicumyl peroxide;

[0012] The crosslinking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, triallyl cyanurate, or triallyl isocyanurate.

[0013] As a preferred embodiment of the present invention, the softener is selected from one or two of naphthenic oil and paraffin oil.

[0014] As a preferred embodiment of the present invention, the flux is at least one of glass micro powder, zinc borate, glass fiber, or inorganic phosphate.

[0015] As a preferred embodiment of the present invention, the inorganic phosphate is ammonium phosphate, ammonium polyphosphate, or ammonium pyrophosphate.

[0016] As a preferred embodiment of the present invention, the flame retardant is selected from at least one of metal hydroxides, metal carbonates, and ammonium polyphosphates.

[0017] Secondly, the present invention provides a method for preparing the above-mentioned fire-retardant and flame-retardant ceramicized EPDM rubber power battery sealing ring material, comprising the following steps:

[0018] S1. Mixing: After plasticizing EPDM rubber, inorganic fillers, softeners, fluxes, flame retardants and crosslinking substances are added in sequence, and then the mixture is mixed to obtain the compound.

[0019] S2. Vulcanization: The compound obtained in step S1 is molded in a vulcanizing machine.

[0020] As a preferred embodiment of the technical solution of the present invention, in step S2, the molding conditions are: temperature 160℃, time 30min, and pressure 10MPa.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The sealing ring material provided by this invention, through the optimization of the types and amounts of the formulation substances, results in a sealing ring material with excellent fire-retardant properties, while also possessing excellent comprehensive properties such as hardness, tensile strength, flexural strength, and elongation at break.

[0023] In the formulation composition provided by the present invention, EPDM can supply a high content of inorganic components required for the formation of ceramics, while maintaining good processing and mechanical properties. It interacts with inorganic fillers, fluxes and other substances, thereby reducing the possibility of shrinkage and breakage when the material is ceramicized under thermal action.

[0024] The sealing ring material provided by this invention is particularly suitable for manufacturing sealing rings for power batteries. Under the high temperature conditions caused by a fire, it can simultaneously provide fire resistance and sufficient strength, which enables the sealing ring to withstand the strength of water jets and gas turbulence in a fire. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. All embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] Unless otherwise specified, all substances involved in this invention were purchased through commercial channels, and information on key substances is described in detail in the specification.

[0027] The applicant discovered through research that using a specific combination of EPDM rubber materials containing fluxes such as glass micropowder, zinc borate, glass fiber, and inorganic phosphates, as well as silicate fillers, can maintain the integrity of the ceramic material. Based on this, the present invention provides a fire-retardant ceramicized EPDM rubber power battery sealing ring material, which, by weight (100%), is made from the following components: 25-60% EPDM rubber, 10-30% inorganic fillers, 1-5% crosslinking material, 5-10% softener, 10-35% flux, and 10-35% flame retardant.

[0028] In the above technical solution, the flux can form a liquid phase at a temperature of 300–800°C. Through the selection of the above substances, the EPDM rubber material obtained by this invention can provide a self-supporting ceramic structure under the high temperatures caused by a fire. The phrase "under the high temperatures caused by a fire" refers to a severe fire situation simulated by heating at 1000°C for 30 minutes.

[0029] The applicant discovered through research that by using fluxes, inorganic fillers, and flame retardants with different melting temperatures, the material can retain its original shape and size because it traps combustion gases during the process of transforming into ceramics at high temperatures caused by a fire. Testing of the EPDM rubber material obtained by this invention revealed that the linear dimension change along the length of the conventional rectangular test sample is less than 10.0%, and the material forms ceramics at high temperatures caused by a fire, with a flexural strength of not less than 1.0 MPa.

[0030] In the above technical solution, the ceramicized EPDM rubber material provides flame-retardant properties at the high temperatures caused by a fire. This ceramicized material comprises inorganic fillers and fluxes, which form a bonded ceramic at the high temperatures caused by a fire. At the high temperatures caused by a fire, the flux glass micropowder / zinc borate and phosphate successively form a liquid phase. Due to the decomposition of EPDM and other components such as ammonium polyphosphate, a dispersed gas phase is formed. When the material temperature rises above approximately 800°C, the material forms a ceramic comprising glass / zinc borate, inorganic phosphate, and inorganic fillers. The shrinkage associated with the decomposition of EPDM and optionally certain inorganic components is compensated by uniformly dispersed pores formed in the temporary liquid phase. The decomposition of the glass micropowder and inorganic phosphate components forms dispersed pores entrained in the temporary liquid phase, which allow the material to substantially retain its original size and shape when transforming into a ceramic. The released gas causes the viscous liquid phase to expand in a controlled manner throughout all stages of the transformation into a ceramic under fire conditions; this expansion is enhanced by combustion residues and inorganic filler particles. The controlled expansion matches the volume loss during combustion, forming a ceramic with a relative strength of at least 0.3 MPa, similar in size and shape to the original product. Controlled dispersion of micropores is formed through the decomposition of inorganic phosphate components in the flux and the interaction between the flux and the filler. These dispersed micropores enable the material to form a ceramic that remains self-supporting even after heating at 1000°C for 30 minutes.

[0031] To test whether a material is self-supporting, the applicant used the following test as a standard. This test involved preparing specimens of the material with dimensions of 30.0 mm × 13.0 mm × 2.0 mm. The specimens were placed on a rectangular refractory material with their major axis perpendicular to one side of the supporting refractory brick, with each specimen having a 13.0 mm long portion extending from the side of the supporting refractory brick. The specimens were then heated to 1000.0 °C at a rate of 12.0 °C / min and held at this temperature in air for 30 minutes. At all temperatures, the specimens of the material maintained rigidity and adhesion, without significant bending at the side of the supporting brick (i.e., the bending angle formed from the original position was less than 15.0°). The resulting ceramic well retained the shape of the specimen before exposure to the high temperature.

[0032] The material of this invention comprises two fluxes with different melting points, which form a liquid phase at a temperature not exceeding 800°C. While the inorganic filler provides self-supporting properties, shape retention, and strength, the amount of inorganic filler is greater than 10.0% based on the total weight of the ceramicized material. When flux is present, the total amount of flux forming a liquid phase at temperatures below 800°C is within a specified range (e.g., 10.0-35.0%). The flux decomposes and forms a liquid phase within a temperature range of approximately 300.0-800.0°C.

[0033] In fires, fluxes that can form a liquid phase at lower temperatures have significant advantages. The applicant has discovered that the liquid phase formed by the flux in the compositions of this invention is only a temporary liquid phase. This liquid phase reacts with other components in the material to form a crystalline phase, and at high temperatures, transforms the material into a solid ceramic. Among the inorganic phosphates in the flux, ammonium polyphosphate, combined with other components of this invention, has the significant advantage of maintaining the integrity of the material. In a particularly preferred embodiment of this invention, a flux capable of forming a liquid is selected and combined with other components to provide properties such as (particularly high viscosity) that can trap a sufficient amount of pores and maintain the shape and size of the product. If the viscosity of the temporary liquid phase formed under these conditions is relatively low, all generated gases may be lost, leading to an increased likelihood of failure due to shrinkage, and the liquid component may also be lost.

[0034] Under the high temperatures caused by a fire, the inorganic phosphates in the material of this invention decompose at a temperature equal to or lower than the decomposition temperature of at least a portion of the other components. For ammonium polyphosphate, the decomposition products include ammonia and phosphoric acid. The ammonia promotes the formation of pores in the ceramic during temporary liquid-phase solidification. The phosphoric acid reacts with any nearby organic material, initially forming char, which is then oxidized and consumed during further heating of the composition to form a ceramic.

[0035] In some embodiments, the density of the EPDM rubber is 900–960 g / cm³. 3 At 125°C, the Mooney viscosity is 55, and the vinyl content is 45%.

[0036] In some embodiments, the inorganic filler is selected from one or more of kaolin, talc, diatomaceous earth, sepiolite, montmorillonite, or mica. The amount of the component should be determined based on the properties of the product.

[0037] In some embodiments, the crosslinking substance comprises a crosslinking agent and a co-crosslinking agent; the crosslinking agent is selected from one or more of benzoyl peroxide, 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane or dicumyl peroxide;

[0038] The crosslinking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, triallyl cyanurate, or triallyl isocyanurate.

[0039] In some embodiments, the softener is selected from one or both of naphthenic oil and paraffin oil. An appropriate amount of softener is added to adjust the hardness and softness of the material.

[0040] In some embodiments, the flux is at least one of glass micropowder, zinc borate, glass fiber, or inorganic phosphate. Typically, the flux forms a liquid at about 300.0°C. Gas is generated through the thermal decomposition of all components in the material. Sources of the generated gas include EPDM, magnesium hydroxide, aluminum hydroxide, and ammonium polyphosphate. Particularly preferred is that the gas-generating component is finely dispersed throughout the ceramic-forming components. The gas-generating component may comprise a mixture of gas-generating compounds at elevated temperatures. Preferably, the gas-generating component generates at least a portion of the gas at a temperature above that at which the inorganic component forming the liquid can form a liquid. The gas phase is trapped by the liquid phase, which is temporarily formed during the transformation of the material into ceramic in fire conditions. This gas phase exists in the ceramic as small pores. The applicant has also discovered that the filler interacts with the liquid phase, providing part of the wall structure defining the pores in the formed ceramic.

[0041] In some embodiments, the inorganic phosphate is ammonium phosphate, ammonium polyphosphate, or ammonium pyrophosphate; more preferably, it is ammonium polyphosphate, and its weight is 50.0-70.0% of the total weight of the flux.

[0042] In some embodiments, the flame retardant is selected from at least one of metal hydroxides, metal carbonates, and ammonium polyphosphates. Adding an appropriate amount of flame retardant further improves the fire-retardant properties of the material.

[0043] Of course, the present invention also provides a method for preparing the above-mentioned fire-retardant ceramicized EPDM rubber power battery sealing ring material, comprising the following steps:

[0044] S1. Mixing: After plasticizing EPDM rubber, inorganic fillers, softeners, fluxes, flame retardants and crosslinking substances are added in sequence, and then the mixture is mixed to obtain the compound.

[0045] S2. Vulcanization: The compound obtained in step S1 is molded in a vulcanizing machine.

[0046] 10. The preparation method according to claim 9, wherein in step S2, the molding conditions are: temperature 160°C, time 30 min, and pressure 10 MPa.

[0047] The technical concept of the present invention will be further described below through specific embodiments.

[0048] Example 1

[0049] A fire-retardant ceramicized EPDM rubber power battery sealing ring material comprises, by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 6.0% (800 mesh), kaolin 8.0% (particle size 10 μm), glass micropowder 7.0% (400 mesh, melting point approximately 300℃), ammonium polyphosphate 15.0%, naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0050] The sample and specimen preparation methods and steps are as follows:

[0051] (1) Mixing

[0052] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0053] (2) Sulfidation

[0054] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0055] (3) Sample preparation and performance testing

[0056] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0057] Example 2

[0058] A fire-retardant ceramicized EPDM rubber power battery sealing ring material comprises the following components by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 6.0% (800 mesh), kaolin 8.0% (particle size 10 μm), glass micro powder 22.0% (400 mesh, melting point approximately 300℃), naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0059] The sample and specimen preparation methods and steps are as follows:

[0060] (1) Mixing

[0061] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0062] (2) Sulfidation

[0063] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0064] (3) Sample preparation and performance testing

[0065] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0066] Example 3

[0067] A fire-retardant ceramicized EPDM rubber power battery sealing ring material comprises the following components by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 6.0% (800 mesh), kaolin 8.0% (particle size 10μm), ammonium polyphosphate 22.0%, naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0068] The sample and specimen preparation methods and steps are as follows:

[0069] (1) Mixing

[0070] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0071] (2) Sulfidation

[0072] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0073] (3) Sample preparation and performance testing

[0074] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0075] Example 4

[0076] A fire-retardant ceramicized EPDM rubber power battery sealing ring material comprises the following components by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 9.0% (800 mesh), kaolin 11.0% (particle size 10 μm), glass micro powder 4.0% (400 mesh, melting point approximately 300℃), ammonium polyphosphate 12.0%, naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0077] The sample and specimen preparation methods and steps are as follows:

[0078] (1) Mixing

[0079] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0080] (2) Sulfidation

[0081] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0082] (3) Sample preparation and performance testing

[0083] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0084] Example 5

[0085] A fire-retardant ceramicized EPDM rubber power battery sealing ring material comprises, by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 3.0% (800 mesh), kaolin 5.0% (particle size 10 μm), glass micropowder 10.0% (400 mesh, melting point approximately 300℃), ammonium polyphosphate 18.0%, naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0086] The sample and specimen preparation methods and steps are as follows:

[0087] (1) Mixing

[0088] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0089] (2) Sulfidation

[0090] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0091] (3) Sample preparation and performance testing

[0092] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0093] Example 6

[0094] A fire-retardant ceramicized EPDM rubber sealing ring material for power batteries comprises the following components by weight percentage: EPDM 40.0% (4045M, Mitsui, Japan), talc 6.0% (800 mesh), kaolin 8.0% (particle size 10 μm), glass micron powder 7.0% (400 mesh, melting point approximately 300℃), ammonium polyphosphate 15.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 15.0%, and polyphosphoric acid 5.0%. (See Table 1.)

[0095] The sample and specimen preparation methods and steps are as follows:

[0096] (1) Mixing

[0097] Before mixing EPDM rubber, clean the two rollers of the two-roll mill with anhydrous ethanol to prevent impurities on the rollers from affecting the experimental process. After the anhydrous ethanol has completely evaporated, adjust the roller gap of the mill to about 1.5 mm. First, place the EPDM raw rubber between the two rollers and plasticize it. After the EPDM raw rubber wraps around the rollers, continue plasticizing for about 10 minutes. Then, add the crosslinking agent, inorganic filler, flux, flame retardant, and softener in sequence, and finally add the crosslinking agent. During the addition process, adjust the gap between the two rollers and mix for about 20 minutes. Control the mixing temperature to avoid scorching of the EPDM. After passing through the mill several times, sheet the rubber and let the sheeted rubber stand for 24 hours for later use.

[0098] (2) Sulfidation

[0099] The compound rubber from (1) was re-milled on a two-roll mill and passed through a thin mill multiple times to produce sheets of a certain thickness. The EPDM compound rubber sheets were then placed into a self-made mold, and the mold was placed in a flat vulcanizing machine for compression molding. During the molding process, the EPDM underwent a crosslinking reaction. The crosslinking conditions were: temperature 160℃, time 30.0 minutes, and pressure 10.0 MPa.

[0100] (3) Sample preparation and performance testing

[0101] The molded sheet was removed from the mold, and samples of different shapes were cut according to the requirements of the testing standards, and different performance tests were conducted on each sample. The results are shown in Table 1.

[0102] Comparative Example 1

[0103] A fire-retardant ceramicized EPDM rubber sealing ring material for power batteries comprises, by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 11.0% (800 mesh), kaolin 13.0% (particle size 10 μm), glass micron powder 12.0% (400 mesh, melting point approximately 300℃), ammonium polyphosphate 20.0%, naphthenic oil 5.0%, dicumyl peroxide 3.0%, and triallyl isocyanurate 1.0%. See Table 1. The sample and specimen preparation methods and procedures are as described in Example 1. Test results are shown in Table 1.

[0104] The biggest difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain a flame retardant, while the other components are the same as in Example 1. However, the weight percentages of filler and flux in Comparative Example 1 are increased by 10.0%, which is the same amount as the amount of flame retardant in Example 1. The material without added flame retardant shows a significantly lower limiting oxygen index, while other properties remain largely unchanged.

[0105] Comparative Example 2

[0106] A fire-retardant ceramicized EPDM rubber sealing ring material for power batteries comprises, by weight percentage: EPDM 35.0% (4045M, Mitsui, Japan), talc 11.5% (800 mesh), kaolin 13.5% (particle size 10 μm), naphthenic oil 5.0%, dicumyl peroxide 3.0%, triallyl isocyanurate 1.0%, aluminum hydroxide 20.5%, and polyphosphoric acid 10.5%. See Table 1. The sample and specimen preparation methods and procedures are as described in Example 1. Test results are shown in Table 1.

[0107] The biggest difference between Comparative Example 2 and Example 1 is that Comparative Example 2 does not contain a flux, while the other components are the same as in Example 1. However, the weight percentages of filler and flame retardant in Comparative Example 2 are increased by 10.5%, which is the same amount as the amount of flux in Example 1. The material without flux shows a significant decrease in linear dimension, limiting oxygen index, flexural strength of ceramic residue, weight of residue, and self-support, while other properties remain largely unchanged.

[0108] The materials of the above embodiments and comparative examples were subjected to performance tests, and the test methods are as follows:

[0109] Tensile strength and elongation at break. Tested according to standard GB / T 528.

[0110] Shore hardness. Tested according to standard GB / T 531.1.

[0111] Compression set. Tested according to standard GB / T 7759.1.

[0112] Limiting Oxygen Index (LOI). Tested according to standard GB / T 10707-2008.

[0113] Slow sintering conditions. The test sample was heated from room temperature to 1000.0°C at a heating rate of 12.0°C / min, and then held at 1000.0°C for 30.0 minutes. These conditions are representative of "high temperature caused by fire".

[0114] Rapid sintering conditions. The test sample was placed in a preheated furnace at 1000.0°C and maintained at that temperature for 30.0 minutes. In this embodiment, certain compositions were exposed to these fire conditions to illustrate the effect of different combustion conditions on certain measured properties. These conditions are representative conditions achieved under very rapid heating.

[0115] Linear dimension change. This linear dimension change is the change along the length of the specimen. The method for determining linear dimension change is to measure the length of the specimen before combustion and after rapid or slow firing followed by cooling. Expansion of the specimen due to combustion is reported as a positive linear dimension change, while contraction is reported as a negative linear dimension change. The changes are listed as percentages.

[0116] Bending strength. The bending strength of ceramics was determined as follows: the test sample was heated under slow firing conditions and cooled. The load was then increased at a crosshead speed of 0.2 mm / min, and the test was performed by three-point bending with a span of 18.0 mm.

[0117] Residue. The substance remaining after a material has been subjected to high temperatures caused by a fire. In this invention, the simulated conditions are that the material is heated from room temperature to 1000.0°C and then held at 1000.0°C for 30.0 minutes.

[0118] Self-supporting. The composition remains rigid without significant heat-induced deformation or flow. The test method involves placing the sample on a rectangular refractory brick with its long axis perpendicular to the edge of the brick, and a 13.0 mm portion extending beyond the edge. The sample is then heated under slow firing conditions, and the cooled sample is tested. A self-supporting sample remains rigid and can support its own weight without significant bending at the edge of the support. Typically, any bending at the edge of the refractory brick forms an angle of less than 15.0° from its original position.

[0119] Table 1 Examples, Comparative Formulations, and Performance

[0120]

[0121]

[0122] Note: Negative values ​​for line dimension changes indicate shrinkage.

[0123] Table 1 lists the composition and properties of the materials. The difference between Examples 2 and 3 and Example 1 is that only one flux was used in these two examples, while Example 1 used two fluxes with different melting temperatures. It is clear from Table 1 that in Example 1, the limiting oxygen index, linear dimension change, flexural strength of the ceramic residue, and weight of the residue are significantly better than in Examples 2 and 3. This indicates that using fluxes with gradient melting temperatures is more effective in ceramicizing EPDM than using a single flux. The difference between Examples 4 and 5 and Example 1 is that the amount of flux was reduced and increased, respectively. Increasing the amount of flux improved the material's properties, while decreasing the amount of flux decreased the material's properties. The difference between Example 6 and Example 1 is that no softener was added to the formulation, and the EPDM content was increased by 5.0%, exactly the amount of softener added in Example 1. The elongation at break, compression set, and hardness of the material were improved, while tensile strength, limiting oxygen index, compression set, linear dimension change, flexural strength of the ceramic residue, and weight of the residue decreased.

[0124] By comparing the test results of Examples 1, 2, and 3, it was found that two fluxes with gradient melting temperatures added to the material had a better ceramicization effect than a single flux.

[0125] Comparing the material properties in the embodiments of Table 1 with the performance requirements of the power battery sealing ring, it is found that the material properties of the present invention meet the requirements of the sealing ring performance, and the material of the present invention can be used to manufacture power battery sealing rings.

[0126] Meanwhile, through Comparative Examples 1, 2 and 1, it is shown that the flux and flame retardant in the material composition have a synergistic effect on the fire prevention and flame retardancy of the material.

[0127] The above description is only a partial embodiment of the present invention and is not intended to limit the present invention in any way. Any simple, non-essential improvements and adjustments made by those skilled in the art to the above embodiments based on the technical solutions of the present invention under the guidance of the present invention shall fall within the protection scope of the present invention.

Claims

1. A fireproof and flame-retardant ceramicized EPDM power battery seal ring material, characterized in that, The raw materials are made into the rubber composition with a weight fraction of 100%, which comprises 25-60% of the ethylene-propylene-diene rubber, 10-30% of the inorganic filler, 1-5% of the cross-linking material, 5-10% of the softening agent, 10-35% of the fluxing agent, and 10-35% of the flame retardant.

2. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 1, characterized in that, The density of the terpolymer is 900 to 960 g / cm 3 , a Mooney viscosity at 125°C of 55 and a vinyl content of 45%.

3. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 1, characterized in that, The inorganic filler is selected from one or more of kaolin, talc, diatomite, sepiolite, montmorillonite, or mica.

4. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 1, characterized in that, The cross-linking material is composed of a cross-linking agent and a co-cross-linking agent; the cross-linking agent is selected from one or more of dibenzoyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, or dicumyl peroxide; The co-cross-linking agent is selected from one or more of trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, triallyl cyanurate, or triallyl isocyanurate.

5. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 1, characterized in that, The softening agent is selected from one or both of naphthenic oil and paraffin oil.

6. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 1, characterized in that, The fluxing agent is at least one of glass micro powder, zinc borate, glass fiber, or inorganic phosphate.

7. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to claim 6, characterized in that, The inorganic phosphate is ammonium phosphate, ammonium polyphosphate, or ammonium pyrophosphate.

8. The fireproof and flame-retardant ceramicized EPDM power battery seal ring material of claim 1, wherein, The flame retardant is selected from at least one of metal hydroxide, metal carbonate, and ammonium polyphosphate.

9. A method for preparing the fireproof and flame-retardant ceramicized EPDM power battery seal ring material according to any one of claims 1-8, characterized in that, The method comprises the following steps: S1, mixing: after plasticizing the ethylene-propylene-diene rubber, the inorganic filler, the softening agent, the fluxing agent, the flame retardant, and the cross-linking material are sequentially added, and then mixed to obtain a mixed rubber; S2, vulcanization: the mixed rubber obtained in step S1 is molded in a vulcanization machine.

10. The method of claim 9, wherein, In step S2, the molding conditions are: temperature 160℃, time 30min, and pressure 10MPa.

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