Irradiation cross-linked polypropylene foam material for power battery gasket as well as preparation method and application of irradiation cross-linked polypropylene foam material

Abstract

The invention discloses an irradiation cross-linked polypropylene foam material for a power battery gasket as well as a preparation method and application of the irradiation cross-linked polypropylene foam material. According to the invention, liquid polyisoprene is adopted as an assistant cross-linking agent, vinyl siloxane-coated azodicarbonamide and zinc dicyandiamide are adopted as a foaming system, homo-polypropylene, low-density polyethylene and an elastomer are compounded, and the irradiation cross-linked polypropylene material with a superfine uniform cellular structure is obtained. The product prepared by the preparation method disclosed by the invention has the following advantages: (1) the product has a uniform foam structure, and the pore diameter is within 0.03 mm; (2) the heat resistance of the product is good and can reach 120 DEG C or above; (3) the product is high in strength and high in foaming ratio, and when the apparent density is less than 0.067 g / cm < 3 > and the thickness is 1mm, the tensile strength is 1.4 MPa or above, and the elongation is 280% or above; (4) the permanent compression deformation rate of the product is within 20%; and (5) the obtained material has wide application in the field of power battery gaskets.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to an irradiated cross-linked polypropylene foam material for power battery gaskets, a preparation method thereof, and an application thereof. Background Art

[0002] Radiation cross-linked polyethylene foam plastic is a foamed plastic with a closed-cell structure between soft (polyurethane) and hard (polystyrene) foam plastics. It has a series of excellent properties such as superior toughness, elasticity, flexibility, wear resistance, chemical corrosion resistance, low-temperature resistance, and good insulation. It can be used as a good insulation, heat insulation, shock-proof, and buoyancy material, and is widely used in various fields such as industry, agriculture, construction, and transportation. However, the application of PE foam plastic is limited due to its poor mechanical properties, poor heat resistance (the maximum use temperature is only about 80 °C), and difficulty in degradation. Polypropylene (PP) foam has many excellent properties, including low price, good heat resistance, high melting point, high tensile modulus, low density, and good chemical resistance, becoming the "new favorite" in the foaming industry. In terms of mechanical properties, PP has a higher static load-bearing capacity than PE and higher impact toughness than PS. Polypropylene (PP) foaming materials have received extensive attention due to their excellent heat resistance, mechanical properties, and environmental friendliness, and have become high-performance green foaming materials to replace PU, PE, and PS foam materials.

[0003] Although it has excellent properties, PP foaming still faces many difficulties. The main reason is that the molecular chain of ordinary PP is a linear structure. During the foaming process, the biaxial stretching force experienced by the cell wall will cause the entanglement of the linear chain to quickly open, and the molecular chain is prone to relative sliding, so the tensile viscosity is relatively low. Even a small stress will cause a large deformation of PP. Therefore, it is manifested that the strength of the cell wall during the foaming process is not high and is prone to rupture. At the same time, a large amount of gas in the bubbles escapes and diffuses into the environment, ultimately resulting in defects such as thick cell wall thickness, uneven cell size, and low foaming ratio of the foamed product. At the same time, due to the high melting point of homopolymer PP, the extrusion processing temperature is above 150 °C. During this high-temperature processing process, the traditional Ac foaming system of polyethylene cannot be used. In the field of power battery gaskets, strict requirements are imposed on the pore structure of the foaming material. Generally, only microcellular foamed polypropylene meets the requirements. However, the preparation conditions of supercritical carbon dioxide microcellular foaming materials are harsh and require high-pressure conditions. There are obvious differences in the foaming degree between the surface and the center of the obtained materials, and it is difficult to meet the requirements of continuous production. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides an irradiated cross-linked polypropylene foam material for power battery gaskets, its preparation method and application. The present invention uses liquid polyisoprene as a co-crosslinking agent to promote the cross-linking of polypropylene, avoid the degradation of tertiary carbon, utilize the high affinity of polyisoprene with PP to promote its uniform distribution in PP, and utilize the high melting point of polyisoprene to solve the problem of migration and precipitation of traditional small molecule co-crosslinking agents. An ethylene silane is used to wrap an azodicarbonamide and a zinc dicyandiamide foaming system. The alkenyl silane participates in cross-linking to form a uniform and fine foaming nucleus, and the pores are evenly distributed; the zinc dicyandiamide and azodicarbonamide are uniformly mixed to promote the uniform progress of the foaming process and avoid the pore structure differences caused by uneven dispersion; the azodicarbonamide is wrapped in the vinyl silane, effectively increasing the foaming pressure and reducing gas escape, forming a uniform and ultra-fine pore structure, and replacing expensive MPP foaming materials.

[0005] To achieve the above invention purpose, the present invention is implemented by the following technical solutions:

[0006] The present invention provides an irradiated cross-linked polypropylene foam material for power battery gaskets. By weight, its raw materials include:

[0007]

[0008] Further, the polypropylene foam material has a fine and uniform pore structure, good heat resistance, reaching above 120 °C; the product has high strength, a large foaming ratio, and an apparent density less than 0.067 g / cm 3 When the thickness is 1 mm, the tensile strength is above 1.4 MPa, and the elongation at break is above 280%; the permanent compression set rate of the product is within 20%.

[0009] Further, the preparation steps of the ethylene silane wrapping azodicarbonamide and zinc dicyandiamide are as follows: Disperse azodicarbonamide and zinc dicyandiamide with a particle size of 15 - 30 um in an ethanol / dimethyl sulfoxide mixed solution, then add vinyltriethoxysilane, carry out a reflux reaction for 5 - 24 h, then carry out centrifugal separation, and vacuum dry to obtain ethylene silane wrapping azodicarbonamide and zinc dicyandiamide.

[0010] Further, the mass ratio of azodicarbonamide, zinc dicyandiamide and the ethanol / dimethyl sulfoxide mixed solution is: 10:0.1 - 2:100; the mass ratio of vinyltriethoxysilane to azodicarbonamide is 1 - 3:1; the volume ratio of ethanol and dimethyl sulfoxide is 1:1.

[0011] Preferably, the preparation steps of the vinyl silane-coated azodicarbonamide and zinc dicyandiamide are as follows: 10 parts by mass of azodicarbonamide with a particle size of 15 - 30 μm and 0.5 parts by mass of zinc dicyandiamide are dispersed in 100 parts by mass of ethanol / dimethyl sulfoxide (V:V = 1), 20 parts by mass of vinyltriethoxysilane is added, and after reflux reaction for 12 h, centrifugal separation is carried out at a centrifugal speed of 2000 rpm for 5 min, and then vacuum drying is carried out at 80 °C to obtain vinyl silane-coated azodicarbonamide and zinc dicyandiamide.

[0012] Further, the elastomer is at least one of ethylene propylene diene monomer rubber, ethylene-octene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, natural rubber, isobutyl rubber, styrene-butadiene rubber, styrene-butadiene block copolymer, and pentaphenyl block copolymer.

[0013] Further, the polypropylene is homopolypropylene with a melt index of 0.5 - 5 g / 10 min and a melting point of 145 - 167 °C; the molecular weight of the liquid polyisoprene is 20000 - 70000, and the viscosity is 50 - 280 Pa·s; the low-density polyethylene is at least one of general low-density polyethylene with a density of 0.901 - 0.922 g / cm 3 , a melt index of 1 - 6 g / 10 min, and linear low-density polyethylene with a density of 0.905 - 0.930 g / cm 3 , and a melt index of 0.3 - 5 g / 10 min.

[0014] Preferably, the molecular weight of the liquid polyisoprene is 30000 - 50000, and the viscosity is 70 - 100 Pa·s.

[0015] Further, the flame retardant is a composite of decabromodiphenylethane and antimony trioxide, and the mass ratio of the two is 3:1; the antioxidant is at least one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, butyl hydroxyanisole, dibutyl hydroxytoluene, propyl gallate, and tert-butylhydroquinone.

[0016] The present invention also provides a preparation method of the irradiated crosslinked polypropylene foam material for the power battery gasket, which includes the following steps:

[0017] (1) Mix polypropylene, elastomer, low-density polyethylene, liquid polyisoprene, vinyl silane-coated azodicarbonamide and zinc dicyandiamide, flame retardant, and antioxidant, and then add them to a screw extruder for mixing and extrusion to obtain a masterbatch;

[0018] (2) Electronically irradiate and crosslink the master sheet, and then subject the obtained material to high-temperature foaming treatment to obtain a polypropylene foam material.

[0019] Further, in the step (1), the extrusion temperature of the screw extruder is 120 - 170 °C, the screw speed is 5 - 50 rpm, and the die head temperature is 160 - 180 °C.

[0020] Further, in the step (2), an electron accelerator is used for irradiation crosslinking, and the irradiation dose of the irradiation crosslinking is 4 - 40 kGy; the high-temperature foaming treatment is carried out in a foaming furnace, the temperature of the foaming furnace is 180 - 280 °C, and the foaming time is 0.1 - 3 min.

[0021] The present invention also provides the application of the irradiated crosslinked polypropylene foam material for power battery gaskets in the preparation of power battery gaskets.

[0022] Further, the thickness of the foam material is 0.1 - 10 mm, and the thickness deviation is within 10%; at least 2 layers of pores are included in the thickness direction; the pore diameter is within 0.05 mm and is evenly distributed.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The pore structure of the product is uniform, and the pore diameter is within 0.03 mm;

[0025] (2) The product has good heat resistance and can reach above 120 °C;

[0026] (3) The product has high strength and a large foaming ratio. When the apparent density is less than 0.067 g / cm3 and the thickness is 1 mm, the tensile strength is above 1.4 MPa and the elongation at break is above 280%;

[0027] (4) The permanent compression set rate of the product is within 20%;

[0028] (5) The obtained material has wide applications in the field of power battery gaskets.

[0029] The present invention uses liquid polyisoprene as a co-crosslinking agent, vinyl siloxane encapsulating azodicarbonamide and zinc dicyandiamide as a foaming system, and a blend of homopolypropylene, low-density polyethylene and elastomer to obtain an irradiated crosslinked high-foaming polypropylene material with an ultra-fine and uniform pore structure, which is the most suitable method at present. Specific embodiments

[0030] In the formula of the polyethylene foam material of the present invention, liquid polyisoprene is used as a co-crosslinking agent, vinyl siloxane is used to wrap azodicarbonamide and zinc dicyandiamide as a foaming system, homopolypropylene, low-density polyethylene and elastomers are compounded, and a three-dimensional cross-linked network is formed through radiation cross-linking and high-temperature foaming to prepare an irradiated cross-linked high-foaming polypropylene material with an ultra-fine and uniform cell structure.

[0031] The preferred embodiments of the present invention will be described in detail below so as to more clearly understand the purpose, features and advantages of the present invention.

[0032] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0033] It should be noted that:

[0034] (1) The present invention uses GB / T 6344-1996 "Testing Methods for Tensile Strength and Elongation at Break of Flexible Cellular Polymer Materials" to test the tensile strength and elongation.

[0035] (2) The present invention uses GBT6669-2001 "Testing Method for Compression Set of Flexible Cellular Polymer Materials" to test the permanent deformation rate of the sample after being compressed to 50% and placed at 100 °C for 24 h and then restored at room temperature for 24 h.

[0036] (3) The present invention uses GB / T 3682-2000 "Determination of Melt Mass-Flow Rate and Melt Volume-Flow Rate of Thermoplastics" to test the melt index.

[0037] (4) The present invention uses GB / T1033-1986 "Test Methods for Density and Relative Density of Plastics" to test the material density.

[0038] (5) The present invention uses GB / T2411-2008 "Plastics and Hard Rubbers - Determination of Indentation Hardness (Shore Hardness) by Means of a Durometer" to determine the surface hardness of the material.

[0039] (6) The present invention uses ASTM D1056 to determine the water absorption of the material.

[0040] Example 1

[0041] A preparation method of an irradiated cross-linked polypropylene foam material (MIXPP) includes the following steps:

[0042] Step 1: Wrap azodicarbonamide and zinc dicyandiamide with vinyl silane

[0043] 10 parts by mass of azodicarbonamide with a particle size of 15 - 30 μm and 0.5 parts by mass of zinc dicyandiamide are dispersed in 100 parts by mass of ethanol / dimethyl sulfoxide (V:V = 1). 20 parts by mass of vinyltriethoxysilane is added, and after reflux reaction for 12 h, centrifugal separation is carried out at a centrifugal speed of 2000 rpm for 5 min, and then vacuum drying is carried out at 80 °C to obtain azodicarbonamide and zinc dicyandiamide wrapped with vinylsilane.

[0044] Step 2: Preparation of polypropylene foam

[0045] 40 parts by weight of homopolypropylene (PP PPC 5660, Total, France, 0.905 g / cm 3 , MI 7 g / 10 min), 5 parts by weight of elastomer (POE Engage 8842, Dow, 0.857 g / cm 3 , MI (230 °C / 2.16 kg) 1.0 g / 10 min), 15 parts by weight of low-density polyethylene (LLDPE 4157, DowDuPont, 0.92 g / cm 3 , MI (230 °C / 2.16 kg) 3.0 g / 10 min), 5 parts by weight of liquid polyisoprene (molecular weight about 30000, viscosity 120 Pa·s), 25 parts by weight of azodicarbonamide and zinc dicyandiamide wrapped with vinylsilane, 10 parts by weight of flame retardant, 2 parts by weight of antioxidant 1010 are added to a screw extruder for plasticizing and extruding a masterbatch. The extrusion temperature is controlled at 135 - 165 °C, the screw speed is 11 rpm, and the die head temperature is 160 °C to obtain a masterbatch with a thickness of 0.3 mm; then, the masterbatch is irradiated and crosslinked through an electron accelerator, and the irradiation dose is controlled at 25 kGy to form a crosslinked polymerization network; finally, the crosslinked masterbatch is placed in a foaming furnace for foaming, the temperature of the foaming furnace is controlled at 180 - 260 °C, and the residence time of the crosslinked masterbatch is 0.3 min to obtain a highly foamed irradiated crosslinked polypropylene foam material with an apparent density of 0.062 g / cm 3 , a thickness of 1 mm, a tensile strength of 2.3 MPa, an elongation at break of 320%, a permanent compression set of 21%, a water absorption rate of 1.4%, no large surface pores, a uniform cell structure, a cell diameter of 0.21 mm, and a smooth surface. This polypropylene foam can be used in the field of power battery gaskets.

[0046] Example 2

[0047] Replace the elastomer in Step 2 of Example 1 with POE Engage 8842 (Dow, 0.87 g / cm 3 , MI 5.0 g / 10 min), and keep other raw materials and steps the same as in Example 1. The index parameters of the obtained highly foamed irradiated crosslinked polypropylene foam material are shown in Table 1.

[0048] Example 3

[0049] Replace the elastomer in the second step of Example 1 with POE Engage 8840 (Dow, 0.897 g / cm 3 , MI 1.6 g / 10 min). Keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foam material are shown in Table 1.

[0050] Example 4

[0051] Replace the elastomer in the second step of Example 1 with POP COHERE 8402 (Saudi Arabia, 0.902 g / cm 3 , MI 3.5 g / 10 min). Keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foam material are shown in Table 1.

[0052] Example 5

[0053] Replace the elastomer in the second step of Example 1 with POP Queo 1001 (Borealis, 0.91 g / cm 3 , MI 1.1 g / 10 min). Keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foam material are shown in Table 1.

[0054] Example 6

[0055] Replace the elastomer in the second step of Example 1 with POP Exact 3132F (Exxon, 0.90 g / cm 3 , MI 1.2 g / 10 min). Keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foam material are shown in Table 1.

[0056] Table 1 Parameters of polypropylene foams prepared with different elastomers

[0057]

[0058] Example 7

[0059] Replace the low-density polyethylene in the second step of Example 1 with LLDPE PP-0118-F (NOVA Canada, 0.918 g / cm 3 , MI 1.0 g / 10 min). Keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foam material are shown in Table 2.

[0060] Example 8

[0061] Replace the low-density polyethylene in the second step of Example 1 with LLDPE WPP692D (Southern, USA, 0.918 g / cm 3 , MI 1.0 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 2.

[0062] Example 9

[0063] Replace the low-density polyethylene in the second step of Example 1 with LLDPE LL1001 (ExxonMobil, 0.918 g / cm 3 , MI 1.0 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 2.

[0064] Example 10

[0065] Replace the low-density polyethylene in the second step of Example 1 with mLLDPE 5220G (DowDuPont, 0.916 g / cm 3 , MI 3.5 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 2.

[0066] Table 2 Parameters of polypropylene foams prepared with different low-density polyethylenes

[0067]

[0068] Example 11

[0069] Replace the polypropylene in the second step of Example 1 with PP R3410 (LG, South Korea, 0.9 g / cm 3 , MI 7 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 3.

[0070] Example 12

[0071] Replace the polypropylene in the second step of Example 1 with PP PC366-3 (Formosa Plastics Corporation, 0.902 g / cm 3 , MI 3.0 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 3.

[0072] Example 13

[0073] Replace the polypropylene in the second step of Example 1 with PP 4017 (Daehan Oil & Chemical Co., 0.9 g / cm 3 , MI 8.5 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 3.

[0074] Example 14

[0075] Replace the polypropylene in the second step of Example 1 with PP H710 (GS Caltex Korea, 0.903 g / cm 3 , MI 0.7 g / 10 min), and keep all other raw materials and steps the same as in Example 1. The index parameters of the prepared high-foamed irradiated cross-linked polypropylene foaming material are shown in Table 3.

[0076] Table 3 Parameters of polypropylene foams prepared from different polypropylenes

[0077]

[0078] Comparative Example 1

[0079] According to the preparation method of Example 1, directly use azodicarbonamide, 40 parts by weight of homopolypropylene (PP PPC5660, Total, France, 0.905 g / cm 3 , MI 7 g / 10 min), 5 parts by weight of elastomer (POE Engage 8842, Dow, 0.857 g / cm 3 , MI (230 °C / 2.16 kg) 1.0 g / 10 min), 15 parts by weight of low-density polyethylene (LLDPE 4157, DowDuPont, 0.92 g / cm 3 , MI (230 °C / 2.16 kg) 3.0 g / 10 min), 5 parts by weight of liquid polyisoprene (molecular weight about 30000, viscosity 120 Pa·s), 25 parts by weight of azodicarbonamide and 1.25 parts by weight of zinc dicyanamide, 10 parts by weight of flame retardant, 2 parts by weight of antioxidant 1010 are added to the screw extruder for plasticizing and extruding the masterbatch. Control the extrusion temperature at 135 - 165 °C, the screw speed at 11 rpm, and the die head temperature at 160 °C to obtain a 0.3 mm thick masterbatch; then, irradiate the masterbatch through an electron accelerator for cross-linking, control the irradiation dose at 25 kGy to form a cross-linked polymerization network; finally, place the cross-linked masterbatch in a foaming furnace for foaming, control the foaming furnace temperature at 180 - 260 °C, and the residence time of the cross-linked masterbatch at 0.3 min to obtain a high-foamed irradiated cross-linked polypropylene foaming material with an apparent density of 0.099 g / cm 3, with a thickness of 0.72 mm, a tensile strength of 0.77 MPa, an elongation at break of 187%, a permanent compression set rate of 61%, a water absorption rate of 2.5%, a poor uniformity of the cell structure, a wide pore size distribution of 0.1 - 3 mm, and this polypropylene foam cannot be used in the field of power battery gaskets.

[0080] It is proved by the above results that the products prepared by the preparation method of the present invention all have good heat resistance, mechanical strength and long-term adhesiveness, and can be used in the field of power battery gaskets.

[0081] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A radiation cross-linked polypropylene foam material for a power battery gasket, wherein the raw materials of the material include, by weight:

2. The polypropylene foam material according to claim 1, characterized in that: The steps for preparing the vinyl silane-encapsulated azodicarbonamide and zinc dicyanamide are as follows: dispersing azodicarbonamide and zinc dicyanamide with a particle size of 15 to 30 μm in an ethanol / dimethyl sulfoxide mixed solution, adding vinyl triethoxysilane, performing a reflux reaction for 5 to 24 hours, performing centrifugal separation, and vacuum drying to obtain the vinyl silane-encapsulated azodicarbonamide and zinc dicyanamide.

3. The polypropylene foam material according to claim 2, characterized in that: The mass ratio of the azodicarbonamide, zinc dicyanamide and ethanol / dimethyl sulfoxide mixed solution is 10:0.1-2:100; the mass ratio of vinyl triethoxysilane to azodicarbonamide is 1-3:1; and the volume ratio of ethanol to dimethyl sulfoxide is 1:

1.

4. The polypropylene foam material according to claim 1, characterized in that: The elastomer is at least one of EPDM rubber, ethylene-octene copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, natural rubber, isobutyl rubber, styrene-butadiene rubber, styrene-butadiene block copolymer and pentylbenzene block copolymer.

5. The polypropylene foam material according to claim 1, characterized in that: The polypropylene is homopolymer polypropylene, with a melt index of 0.5-5 g / 10 min and a melting point of 145-167° C. The molecular weight of the liquid polyprene is 20,000-70,000, and the viscosity is 50-280 Pa·s. The low-density polyethylene has a density of 0.901-0.922 g / cm 3 , general low-density polyethylene with a melt index of 1 to 6 g / 10 min, and a density of 0.905 to 0.930 g / cm 3 , at least one of linear low-density polyethylenes having a melt index of 0.3 to 5 g / 10 min.

6. The polypropylene foam material according to claim 1, characterized in that: The flame retardant is a composite of decabromodiphenylethane and antimony trioxide, and the mass ratio of the two is 3:1; the antioxidant is at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl ester, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, butylated hydroxyanisole, dibutylhydroxytoluene, propyl gallate, and tert-butylhydroquinone.

7. The method for preparing the radiation cross-linked polypropylene foam material for power battery gasket according to claim 1, characterized in that: The following steps are involved: (1) mixing polypropylene, elastomer, low-density polyethylene, liquid polyprene, vinyl silane-coated azodicarbonamide and zinc dicyanamide, flame retardant, and antioxidant, and adding the mixture into a screw extruder for mixing and extrusion to obtain a master sheet; (2) The master sheet is cross-linked by electron irradiation, and then the obtained material is subjected to high-temperature foaming treatment to obtain a polypropylene foam material.

8. The preparation method according to claim 7, characterized in that: In the step (1), the extrusion temperature of the screw extruder is 120-170°C, the screw speed is 5-50 rpm, and the die temperature is 160-180°C.

9. The preparation method according to claim 7, characterized in that: In the step (2), an electron accelerator is used for radiation crosslinking, and the radiation dose of the radiation crosslinking is 4 to 40 kGy; the high-temperature foaming treatment is carried out in a foaming furnace, the temperature of the foaming furnace is 180 to 280° C., and the foaming time is 0.1 to 3 minutes.

10. Use of the radiation cross-linked polypropylene foam material for power battery gaskets according to claim 1 in the preparation of power battery gaskets.

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