Vinyl polyolefin elastomer-based door sealant particles, preparation method, and door sealant

Abstract

The present invention provides a door seal strip granule made of vinyl polyolefin elastomer, a preparation method thereof, and a door seal strip, belonging to the technical field of compositions of polyolefins and high molecular compounds. Calculated by weight parts, the door seal strip granule made of vinyl polyolefin elastomer comprises: 20-50 parts of white mineral oil, 10-48 parts of polypropylene, 10-50 parts of vinyl polyolefin elastomer, 5-25 parts of calcium carbonate, 0-0.1 part of antioxidant, and 0-0.1 part of lubricant; wherein, the degree of branching of the vinyl polyolefin elastomer is 70-130 branches / 1000 carbons, the weight average molecular weight is 77,000-521,000, the molecular weight distribution index is 1.5-3.0, and the melt index is 1-10 g / 10 min.

Description

Technical Field

[0001] The present invention belongs to the technical field of compositions of polyolefins and high molecular compounds, and more specifically relates to the technical field of door seals for refrigerators and freezers, and in particular to a door seal granule made of vinyl polyolefin elastomer material, a preparation method, and a door seal. Background Art

[0002] Most of the door seals used in current market refrigerators and freezers are made of soft polyvinyl chloride (PVC), and a small amount are made of thermoplastic elastomer (TPE). Compared with PVC, TPE material is more suitable for preparing door seals for refrigerators and freezers. The specific reasons are as follows: First, TPE has excellent low-temperature resistance (-24°C - 4°C) and can still maintain good elasticity in low-temperature environments; second, TPE has good anti-migration properties and will not cause problems such as the rupture of plastic-absorbed parts or the corrosion and adhesion of paint surfaces due to the migration of plasticizers in PVC; third, the molecular structure is stable, and the mechanical strength and elasticity are also better, which can reduce deformation and ensure the refrigeration effect; TPE has stronger anti-aging properties and can still maintain good elasticity and appearance after long-term use, with a longer service life, and TPE is an environmentally friendly material.

[0003] The existing formula for preparing door seal granules using TPE material contains styrene-ethylene / butene-styrene block copolymer (SEBS), and the ethylene / butene rubber segment (EB) in the middle of the molecular structure provides elasticity. In a low-temperature (-24°C - 4°C) environment, the molecular chain movement ability of the rubber segment will weaken as the temperature decreases. Therefore, when the temperature drops, although the SEBS material can maintain a certain flexibility, its low-temperature resistance is relatively limited and can only meet the application scenarios with relatively low requirements for low-temperature (-18°C - 4°C) performance, but it cannot meet the application scenarios with even lower temperature resistance (-60°C to -25°C). In addition, when the SEBS material comes into contact with oil substances, it is prone to swelling, resulting in a decrease in its elasticity. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a door seal granule made of vinyl polyolefin elastomer material, a preparation method, and a door seal, in order to at least partially solve the above technical problems. For this, the technical solutions provided by the present invention are as follows.

[0005] As a first aspect of the present invention, there is provided a door seal strip particle made of vinyl polyolefin elastomer. By weight parts, the door seal strip particle comprises: 20 - 50 parts of white mineral oil, 10 - 48 parts of polypropylene, 10 - 50 parts of vinyl polyolefin elastomer, 5 - 25 parts of calcium carbonate, 0 - 0.1 part of antioxidant, and 0 - 0.1 part of lubricant; wherein, the degree of branching of the vinyl polyolefin elastomer is 70 - 130 branches / 1000 carbons, the weight-average molecular weight is 77,000 - 521,000, the molecular weight distribution index is 1.5 - 3.0, and the melt index is 1 - 10 g / 10 min.

[0006] As a second aspect of the present invention, there is provided a method for preparing a door seal strip particle made of vinyl polyolefin elastomer, comprising: step (1) blending white mineral oil, polypropylene, vinyl polyolefin elastomer, calcium carbonate, antioxidant, and lubricant to obtain a mixed material; step (2) feeding the mixed material into a twin-screw extruder for extrusion granulation to obtain a door seal strip particle made of vinyl polyolefin elastomer.

[0007] As a third aspect of the present invention, there is provided a door seal strip prepared by using the above-mentioned door seal strip particle made of vinyl polyolefin elastomer.

[0008] In an embodiment of the present invention, the vinyl polyolefin elastomer (EPOE) is mainly a polyolefin chain composed of carbon-carbon single bonds. The molecular chain is relatively flexible as a whole and the glass transition temperature is lower than that of SEBS. When it is used as a raw material to prepare a door seal strip, it can maintain good elasticity in a lower temperature (-60°C) environment. In addition, the molecular chain of EPOE is relatively regular, the molecular chains in the crystalline region are arranged closely and the intermolecular force is relatively strong. This intermolecular force enables the door seal strip prepared from EPOE raw material to have certain physical strength while having elasticity, such as tensile strength and tear strength. In addition, since EPOE does not contain unsaturated groups and the molecular chain structure is stable, the prepared door seal strip particle has good oil resistance, water vapor barrier property and weather resistance when facing water vapor, oil stain, oxidation, light, etc. In addition, the method for preparing the door seal strip particle made of vinyl polyolefin elastomer in the present invention is relatively simple and the cost is relatively low. Detailed Embodiments

[0009] In the process of implementing the concept of the present invention, it is found that the existing formula for preparing door seal strip particles using TPE materials mainly includes: styrene-ethylene / butene-styrene block copolymer (SEBS), white mineral oil, polypropylene (PP), polyethylene (PE), calcium carbonate, and other additives. The ethylene / butene rubber segment (EB) in the SEBS molecular structure provides elasticity. In a low-temperature environment (-24°C - 4°C), the molecular chain movement ability of the rubber segment weakens as the temperature decreases. However, due to the presence of styrene blocks in the SEBS molecular chain segments, they can, to a certain extent, limit the excessive convergence and hardening of the molecular chains. Therefore, when the temperature drops, SEBS can still maintain a certain degree of flexibility, but its low-temperature resistance is relatively limited. In the face of a lower temperature environment (such as -60°C), such rubber materials often have problems such as poor sealing and buffer failure. In addition, when the SEBS material comes into contact with oil substances, it is prone to swelling, which easily leads to a decline in its physical properties, such as changes in size and reduction in elasticity. In addition, the preparation cost of door seal strip particles in the TPE formulation system is relatively high, and the processing fluidity is poor.

[0010] In view of the above problems, the present invention proposes to use EPOE as a raw material to prepare door seal strip particles, taking advantage of the good elasticity, physical strength, and lower glass transition temperature (T g of -50°C to -70°C) of EPOE, so that the prepared door seal strip particles made of EPOE have the characteristic of being resistant to lower temperatures (-60°C), and at the same time have good elasticity, physical strength, and stability at lower temperatures (-60°C).

[0011] Specifically, as the first aspect of the present invention, there is provided a door seal strip particle made of vinyl polyolefin elastomer. By weight, the door seal strip particles include: 20 - 50 parts of white mineral oil, 10 - 48 parts of polypropylene, 10 - 50 parts of vinyl polyolefin elastomer (EPOE), 5 - 25 parts of calcium carbonate, 0 - 0.1 part of antioxidant, and 0 - 0.1 part of lubricant; wherein, the degree of branching of EPOE is 70 - 130 branches / 1000 carbons, the weight-average molecular weight (M w is 77,000 - 521,000, the molecular weight distribution index (PDI = M w / M n , M n is the number-average molecular weight) is 1.5 - 3.0, and the melt index is 1 - 10 g / 10 min.

[0012] In an embodiment of the present invention, EPOE is mainly a polyolefin chain composed of carbon-carbon single bonds. The molecular chain is relatively flexible as a whole and has a lower glass transition temperature, enabling such a flexible molecular chain to maintain good elasticity even at lower temperatures. Consequently, the door seal strip prepared from EPOE also has better low-temperature resistance characteristics and is not prone to deformation and cracking at lower temperatures. Further, since the degree of branching of EPOE is not less than 70 branches / 1000 carbons, the door seal strip particles prepared from EPOE are more easily post-processed and modified, thereby being endowed with more functions. The higher the degree of branching and the weight-average molecular weight of EPOE, the higher the grafting rate of the subsequent grafting reaction with the grafting agent, resulting in better application effects and processing properties of the grafted product. The molecular weight distribution index of EPOE (PDI = 1.5 - 3.0) is relatively narrow, indicating that the molecular weight and molecular chain of EPOE are relatively consistent and the distribution is relatively uniform, endowing it with good tensile toughness and impact toughness. Furthermore, it ensures that the door seal strip particles made of EPOE material have more excellent mechanical properties and processing properties and are not prone to abnormal situations such as excessive degradation or crosslinking. Additionally, because the molecular chain size of EPOE is uniform and the entanglement of the molecular chains is relatively stable, the process of preparing the door seal strip particles is more controllable and the quality of the door seal strip particles is more stable. The melt index of EPOE is moderate. Too low or too high a melt index will affect the flowability of the door seal strip particles, resulting in poor processing performance and difficult molding.

[0013] In addition, since EPOE does not contain unsaturated groups (such as double bonds) that are easily oxidized and the molecular chain structure is relatively stable, the door seal strip particles prepared from EPOE have good resistance to acid-base corrosion, oil resistance, weather resistance, and good water vapor barrier properties.

[0014] According to an embodiment of the present invention, EPOE is selected from that produced by Hefei Zhongke Kele New Materials Co., Ltd. The preparation of EPOE includes: under the action of a late transition metal catalyst (i.e., the main catalyst) and a cocatalyst, catalytic polymerization of ethylene monomers is carried out to obtain it. Since only ethylene monomers are used as raw materials, the cost of synthesizing EPOE is significantly reduced, and thus the cost of preparing the door seal strip particles made of EPOE material is reduced. For the late transition metal catalyst, an α-diimine nickel catalyst with the structure shown in formula (1) can be selected, or an α-diimine palladium catalyst with nickel (Ni) replaced by palladium (Pd); the cocatalyst is selected from at least one of alkylaluminoxane and alkylaluminum. Formula (1); wherein, R1 and R8 each independently selected from any one of hydrogen, C1-C6 alkyl, halogen, halogen-substituted C1-C6 alkyl, nitro, C1-C6 alkoxy, trifluoromethyl; R2, R7, R9, R 12 each independently selected from hydrogen, C1-C6 alkyl, halogen, halogen-substituted C1-C6 alkyl; R3, R6, R 10 、R11 Each independently selected from any one of hydrogen, C1-C6 alkyl, halogen, halogen-substituted C1-C6 alkyl, phenyl, and benzhydryl, R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, phenyl, C6-C 30 substituted phenyl, X is selected from any one of halogen, C1-C6 alkane, C2-C6 alkene, allyl or benzyl, and the halogen is selected from Cl or Br.

[0015] According to an embodiment of the present invention, based on the weight parts, the door seal strip particles made of vinyl polyolefin elastomer material further include: 0.1-0.2 parts of initiator and 0.5-3 parts of grafting agent.

[0016] In an embodiment of the present invention, EPOE has a relatively high degree of branching (70-130 branches / 1000 carbons), making it easier to carry out graft modification and capable of grafting more grafting agents, so that the obtained door seal strip particles have more excellent properties. Further, according to the different grafting agents, the door seal strip particles can be given different properties, such as antibacterial property, wear resistance, hydrophobicity, etc.

[0017] According to an embodiment of the present invention, the degree of branching of EPOE is 70-130 branches / 1000 carbons, and the weight average molecular weight is 77,000-521,000; further, the degree of branching of EPOE is preferably 78-120 branches / 1000 carbons, the weight average molecular weight is 84,000-424,000, the molecular weight distribution index is 1.8-2.8, and the melt index is 2-6 g / 10 min; furthermore, the degree of branching of EPOE is 80-110 branches / 1000 carbons, the weight average molecular weight is 162,000-384,000, the molecular weight distribution index is 2.0-2.6, and the melt index is 2.5-5 g / 10 min. The higher the degree of branching of EPOE, the easier it is to carry out post-processing modification on the door seal strip particles prepared by using EPOE, and more abundant functions can be imparted. In addition, the relatively high degree of branching of EPOE enables it to have good tolerance to a variety of chemical substances, enabling it to maintain stable properties in a relatively harsh chemical environment, such as maintaining elasticity and physical strength in a lower temperature environment (such as -60°C).

[0018] In the embodiments of the present invention, in terms of fluidity: the branched structure in EPOE hinders the close packing of molecular chains, relatively reducing the entanglement between molecular chains, thereby increasing the fluidity of the polymer. When performing post-processing modification operations such as injection molding and extrusion, good fluidity facilitates the better filling of the mold and passing through the die by the door seal strip particles, which is beneficial to the forming process. In terms of reactive sites: a higher degree of branching means more reactive sites at the ends of the branches on the molecular chain. When performing chemical modification reactions such as graft copolymerization and crosslinking, more reactive sites can participate in the reaction, increasing the probability and efficiency of the reaction, and enabling the easier introduction of new functional groups or the construction of new structures to achieve diverse modification purposes. In terms of flexibility and plasticity: a higher degree of branching makes the polymer molecular chain morphology more stretched and loose, with better overall flexibility, and it is more likely to change shape when subjected to external forces. Thus, during post-processing such as blow molding and calendering, it can be more smoothly shaped into the corresponding shape according to the process requirements, with stronger plasticity.

[0019] According to the embodiments of the present invention, the white mineral oil can be selected from at least one of 3# white mineral oil, 5# white mineral oil, 7# white mineral oil, 10# white mineral oil, 15# white mineral oil, and 26# white mineral oil. The white mineral oil is mainly used for lubrication, waterproofing and moisture-proofing, adjusting the hardness of the door seal strip particles, improving the flexibility and elasticity of the door seal strip particles, and facilitating the extrusion during the processing.

[0020] According to the embodiments of the present invention, the calcium carbonate is selected from at least one of light calcium carbonate, heavy calcium carbonate, and nano calcium carbonate. The calcium carbonate is mainly used to enhance the physical properties (such as wear resistance, hardness, and tear resistance), stability of the door seal strip particles, improve the processing performance while reducing the cost.

[0021] According to the embodiments of the present invention, the polypropylene is selected from at least one of homopolypropylene, block copolymerized polypropylene, and random copolymerized polypropylene. For example, it can be selected from any one of the polypropylene grades such as K8003, K7227H, K9829H, Z30S, T30S, 500N, and F300M. These polypropylenes are all commercially available, and the parameters of the polypropylene can be queried.

[0022] According to an embodiment of the present invention, the antioxidant is selected from at least one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (antioxidant 1076), tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), dibutylhydroxytoluene, butylated hydroxyanisole, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-thiobis(6-tert-butyl-m-cresol), dipentaerythritol diphosphite distearyl ester, dipentaerythritol diphosphite dioctadecyl ester, dilauryl thiodipropionate, distearyl thiodipropionate, tris(nonylphenyl) phosphite, and tris(nonylphenyl) phosphite. The antioxidant can effectively protect the door sealant particles from air oxidation, thereby extending the service life of the door sealant particles.

[0023] According to an embodiment of the present invention, the lubricant is selected from at least one of stearic acid, calcium stearate, zinc stearate, ethylene bisstearamide (EBS), paraffin wax, polyethylene wax (PE wax), oxidized polyethylene wax (OPE wax), fatty acid ester, pentaerythritol stearate (PETS), montan wax, silicone oil, magnesium stearate, barium stearate, N,N'-ethylenebisoleamide, stearamide, erucamide, liquid paraffin, and microcrystalline wax. Adding a lubricant to the door sealant particles can improve the fluidity and plasticity of the particles during the production process, reduce the frictional resistance between the particles, and thus improve the preparation quality of the door sealant particles; adding a lubricant can also extend the service life of the door sealant particles.

[0024] According to an embodiment of the present invention, the initiator is a peroxide. Further, the peroxide is selected from at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butyl peroxy-2-ethylhexyl carbonate. The initiator is mainly used to initiate the grafting reaction of EPOE and the grafting agent, so that the door sealant particles have richer properties, such as antibacterial property, wear resistance, compatibility, etc., and thus have a wider application scenario.

[0025] According to an embodiment of the present invention, the grafted substance is selected from at least one of a compatibilizing monomer, an antibacterial monomer, and a hydrophobic monomer. Further, the compatibilizing monomer is selected from at least one of maleic anhydride, methacrylic acid, acrylic acid, itaconic acid, fumaric acid, isocyanate, glycidyl methacrylate, methyl methacrylate, dibutyl fumarate, β-hydroxyethyl methacrylate, dibutyl maleate, and diethyl maleate. Specifically, maleic anhydride: Since maleic anhydride contains an unsaturated double bond and an acid anhydride group, after EPOE is grafted with maleic anhydride, the reaction activity can be increased, and it can react with other substances containing active groups, thereby improving the compatibility and adhesion with other materials. Methacrylic acid: Because it contains a carboxyl group, it can provide an acidic environment, react with alkaline substances, and also improve the adsorption performance of EPOE and the compatibility with other materials containing functional groups. Acrylic acid, itaconic acid, and fumaric acid: Containing carboxyl groups can enhance the acidity of EPOE, enabling it to be better compatible with some alkaline additives and used to adjust the pH value. Isocyanate: After grafting, it can react with compounds containing active hydrogen (such as hydroxyl groups and amino groups), and by forming urea bonds or urethane bonds, the crosslinking density is increased, thereby improving the strength and wear resistance of the door seal strip particles. Glycidyl methacrylate: After grafting, its epoxy group can react with substances containing active hydrogen (such as hydroxyl groups, amino groups, etc.), and the double bond it contains can participate in the polymerization reaction, so that reactive groups can be introduced, which is used to prepare materials with special functions, such as improving the adhesion and chemical stability of the door seal strip particles. Methyl methacrylate: After grafting, it can increase the hardness and transparency of the door seal strip particles. Dibutyl fumarate: The ester group it contains can, after grafting, lower the glass transition temperature and still maintain a certain flexibility at low temperatures (such as -60°C), and can also improve the processing performance of the door seal strip particles. β-Hydroxyethyl methacrylate: Containing a hydroxyl group can provide reaction activity and can react with other materials containing functional groups, such as reacting with isocyanate, to prepare door seal strip particles with good flexibility and adhesion. Dibutyl maleate: The ester group it contains reduces the rigidity of the material, making it easier to process and form. After grafting, it can reduce the rigidity of the door seal strip particles and facilitate processing and forming. Diethyl maleate: After grafting, it reduces the hardness of EPOE through the ester group and improves the flexibility. And because it contains a double bond, it can change the molecular structure of EPOE in the polymerization reaction and increase the compatibility of EPOE with other organic components.

[0026] According to an embodiment of the present invention, the sulfide can be selected from sulfur dioxide or sulfinyl chloride. After grafting with the sulfur compound, the antioxidant property and stability of the door seal strip particles can be improved, and the service life of the door seal strip particles can be extended.

[0027] According to an embodiment of the present invention, the antibacterial monomer is selected from quaternary ammonium salts or phenols, wherein the quaternary ammonium group or phenolic hydroxyl group can play an antibacterial role and inhibit the growth and reproduction of bacteria, thereby achieving the purpose of antibacterial. Therefore, by adding the antibacterial monomer, the obtained door sealant particles have antibacterial properties. Further, the quaternary ammonium salts are selected from at least one of methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, dimethyldiallyl ammonium chloride, methacryloyloxyethyl benzyl dimethyl ammonium chloride, and methacryloyloxyethyl - m - chlorobenzyl - dimethyl ammonium chloride. The phenols are selected from at least one of p - vinylphenol, p - hydroxybenzyl methacrylate, o - cresol, m - cresol, p - cresol, and bisphenol A.

[0028] According to an embodiment of the present invention, the hydrophobic monomer is selected from at least one of polydimethylsiloxanol, lactic acid - modified siloxane, amino acid - modified siloxane, starch - modified siloxane, cellulose - modified siloxane, chitosan - modified siloxane, fatty acid - modified siloxane, terpene - modified siloxane, lignin - modified siloxane, protein - modified siloxane, polydimethylsiloxane, cyclic polydimethylsiloxane, phenylpolymethylsiloxane, methyl - vinylsiloxane, diphenylsiloxane, methyloctylsiloxane, hydroxy - terminated ethoxypropoxylated - dimethylsiloxane, octakis(trimethylsiloxy)silsesquioxane, and γ - glycidoxypropyltrimethoxysilane.

[0029] As a second aspect of the present invention, there is provided a method for preparing the door sealant particles made of the vinyl polyolefin elastomer material in the above - mentioned embodiment, including: Step (1) blending white mineral oil, polypropylene, EPOE, calcium carbonate, antioxidant, and lubricant to obtain a mixed material; Step (2) feeding the mixed material into a twin - screw extruder for extrusion granulation to obtain the door sealant particles made of the vinyl polyolefin elastomer material.

[0030] In an embodiment of the present invention, white mineral oil, polypropylene, EPOE, calcium carbonate, antioxidant, and lubricant are weighed according to a ratio, mixed evenly, and then extrusion granulated to prepare the door sealant particles. The preparation method is relatively simple, has high fluidity, and low cost.

[0031] For example: by weight, 25 parts of white mineral oil, 30 parts of polypropylene, 20 parts of EPOE, 25 parts of calcium carbonate, 0.1 part of antioxidant, and 0.1 part of lubricant are blended in a three - dimensional integrated blender for 2 - 4 h to obtain a mixed material. After the white mineral oil is fully absorbed, the mixed material is fed into a twin - screw extruder for extrusion granulation to obtain the door sealant particles made of EPOE material. Among them, the ratio of the length to the diameter of the twin - screw extruder is greater than or equal to 45, the temperature of each zone of the twin - screw extruder is preferably 150°C - 220°C, the feeding speed of the twin - screw extruder is greater than or equal to 20 Hz, and the main engine speed of the twin - screw extruder is greater than or equal to 400 r / min.

[0032] According to an embodiment of the present invention, in step (1), it further includes: adding an initiator and a grafting agent to initiate the grafting reaction between EPOE and the grafting agent through the initiator, so that EPOE has richer properties. Specifically, in another embodiment, a method for preparing door seal strips particles made of vinyl polyolefin elastomer material includes: in the presence of an initiator, after the grafting agent and EPOE undergo a grafting reaction to form vinyl polyolefin elastomer-grafting agent, it is then blended with white mineral oil, polypropylene, calcium carbonate, antioxidant, and lubricant to obtain a mixed material. Subsequently, the mixed material is put into a twin-screw extruder for extrusion granulation to obtain door seal strips particles made of vinyl polyolefin elastomer material containing the grafting agent. It should be noted that: the dosages of EPOE, white mineral oil, polypropylene, calcium carbonate, antioxidant, lubricant, etc. involved in the method for preparing door seal strips particles made of vinyl polyolefin elastomer material in this embodiment are as in the above embodiment, and will not be elaborated in detail here.

[0033] For example: by weight, 100 parts of EPOE, 0.1 part of initiator, and 0.5 part of grafting agent are weighed for grafting reaction to obtain vinyl polyolefin elastomer-grafting agent. Subsequently, 25 parts of white mineral oil, 30 parts of polypropylene, 20 parts of vinyl polyolefin elastomer-grafting agent, 25 parts of calcium carbonate, 0.1 part of antioxidant, and 0.1 part of lubricant are blended in a three-dimensional mixer for 2 - 4 h to obtain a mixed material. The mixed material is put into a twin-screw extruder for extrusion granulation to obtain door seal strips particles made of vinyl polyolefin elastomer material containing the grafting agent.

[0034] As the third aspect of the present invention, a door seal strip is provided, which is prepared by using the door seal strips particles made of vinyl polyolefin elastomer material in the above embodiment.

[0035] In the embodiment of the present invention, the door seal strip prepared by using the door seal strips particles provided by the present invention can withstand lower temperatures (-60 °C) and maintain good elasticity and physical strength; when facing water vapor, oil stains, oxidation, light, etc., the door seal strip is relatively stable.

[0036] The technical solution of the present invention will be further described in detail below with specific embodiments.

[0037] Experimental test method

[0038] Melt flow rate (i.e., melt index, unit: g / 10 min), the test condition is the number of grams of molten material (such as door seal strips particles or vinyl polyolefin elastomer) flowing out through a standard capillary within 10 min under the conditions of 190 °C and 5 kg, and the specific detection standard refers to Table 3.

[0039] Antibacterial rate test: The film contact antibacterial experiment method is adopted, that is, a film containing bacteria is pasted on the sample to be tested (such as a door seal), and after culturing for a period of time, the growth of bacteria is observed. The antibacterial rate is calculated by comparing the growth of bacteria in the control group and the test group. The specific detection standard is referred to Table 3.

[0040] Water vapor barrier performance test: The electrolytic sensor method is used, that is, by measuring the current change caused by the water vapor concentration difference on both sides of the material (such as a door seal), the water vapor transmission rate is calculated, and the water vapor barrier performance of the material is evaluated. The specific detection standard is referred to Table 3.

[0041] Oil resistance performance test: The door seal particles are made into dumbbell-shaped specimens. The length of the middle parallel part (narrow part) is 115 mm, the width is 6 mm, and the thickness is 0.5 mm. After being completely immersed in edible blended oil for 24 h, the change in mechanical properties before and after immersion is tested. The specific detection standard is referred to Table 3.

[0042] Example 1

[0043] The door seal particles made of ethylene vinyl olefin elastomer (EPOE) include, by weight parts: 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of EPOE, 0.05 part of antioxidant 1010 (pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]), 0.05 part of antioxidant 168 (tris [2,4-di-tert-butylphenyl] phosphite), 0.1 part of lubricant ethylene bisstearamide (EBS). Among them, the degree of branching of EPOE is around 95 branches / 1000 carbons, the weight average molecular weight is around 300,000, the molecular weight distribution index PDI is around 2.6, and the melt index is around 5 g / 10 min (190 °C, 2.16 kg).

[0044] The method for preparing door seal particles made of ethylene vinyl olefin elastomer (EPOE) includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of EPOE, 0.05 part of antioxidant 1010, 0.05 part of antioxidant 168, and 0.1 part of lubricant EBS into a three-dimensional integrated blender and blending for 4 h. After the 10# white mineral oil is fully absorbed, the obtained mixed material is put into a twin-screw extruder for melt extrusion granulation to obtain door seal particles made of EPOE. Among them, the length-diameter ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150 °C - 220 °C, the feeding speed of the twin-screw extruder is 20 Hz, and the main engine speed of the twin-screw extruder is 400 r / min.

[0045] Furthermore, the door seal particles obtained in Example 1 were prepared into door seals and their performance was tested. The specific test results are shown in Table 1, wherein Table 3 shows the standards for various technical indicators of the door seal, including hardness, melt flow rate, tensile strength, elongation at break and density, as well as reference testing standards.

[0046] Example 2

[0047] The antibacterial vinyl polyolefin elastomer (EPOE-1) includes, by weight, 100 parts of EPOE, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of methacryloyloxyethyl trimethyl ammonium chloride (antibacterial monomer). The branching degree of EPOE is around 95 branches / 1000 carbons, the weight average molecular weight is around 300,000, the molecular weight distribution index PDI is around 2.6, and the melt index is around 5g / 10min (190°C, 2.16kg).

[0048] The method for preparing an antibacterial vinyl polyolefin elastomer (EPOE-1) comprises: weighing 100 parts of EPOE, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of methacryloyloxyethyl trimethyl ammonium chloride (antibacterial monomer) in a three-dimensional mixer and mixing them thoroughly for 30 minutes, then taking out the obtained mixture and putting it into a twin-screw extruder that has been heated in advance for melt extrusion granulation to obtain an antibacterial vinyl polyolefin elastomer, named EPOE-1. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0049] The method for preparing door seal particles of vinyl polyolefin elastomer (EPOE-1) material with antibacterial properties comprises: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of EPOE-1, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 parts of lubricant EBS in a three-dimensional blender, and blending for 4 hours. After the 10# white mineral oil is fully absorbed, the obtained mixture is put into a twin-screw extruder for melt extrusion granulation to obtain door seal particles of EPOE-1 material. The aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C-220°C, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0050] Furthermore, the door seal particles obtained in Example 2 were prepared into door seals and their performance was tested. The specific test results are shown in Table 1.

[0051] Example 3

[0052] The difference between Example 3 and Example 2 is that the door seal particles are made of vinyl polyolefin elastomer (EPOE-2) with oil resistance and water vapor barrier properties, and the specific preparation process is as follows.

[0053] The vinyl polyolefin elastomer (EPOE-2) with oil resistance and water vapor barrier includes, by weight, 100 parts of EPOE, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of polydimethylsiloxane (hydrophobic monomer). Among them, the branching degree of EPOE is around 95 branches / 1000 carbons, the weight average molecular weight is around 300,000, the molecular weight distribution index PDI is around 2.6, and the melt index is around 5g / 10min (190℃, 2.16kg).

[0054] The method for preparing a vinyl polyolefin elastomer (EPOE-2) with oil resistance and water vapor barrier includes: weighing 100 parts of EPOE, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of polydimethylsiloxane in a three-dimensional mixer and mixing them thoroughly for 30 minutes, taking out the obtained mixture and putting it into a twin-screw extruder that has been heated in advance for melt extrusion granulation to obtain a vinyl polyolefin elastomer with oil resistance and water vapor barrier, named EPOE-2. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0055] The method for preparing door seal particles of vinyl polyolefin elastomer (EPOE-2) material with oil resistance and water vapor barrier includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of EPOE-2, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 parts of lubricant EBS in a three-dimensional integrated blender, and blending for 4 hours. After the 10# white mineral oil is fully absorbed, the obtained mixture is put into a twin-screw extruder for melt extrusion granulation to obtain EPOE-2 door seal particles. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0056] Furthermore, the door seal particles obtained in Example 3 were prepared into door seals and their performance was tested. The specific test results are shown in Table 1.

[0057] Comparative Example 1

[0058] The door seal strip particles made of SEBS thermoplastic elastomer material, by weight parts, include: 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 15 parts of SEBS, 5 parts of EVA, 0.05 part of antioxidant 1010, 0.05 part of antioxidant 168, 0.1 part of lubricant ethylene bisstearamide (EBS). Among them, the SEBS thermoplastic elastomer selects 250N of Celanese Corporation of the United States.

[0059] The method for preparing the door seal strip particles made of SEBS thermoplastic elastomer material includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 15 parts of SEBS, 5 parts of EVA, 0.05 part of antioxidant 1010, 0.05 part of antioxidant 168, 0.1 part of lubricant EBS into a three-dimensional integrated blender and blending for 4 h. After the 10# white mineral oil is fully absorbed, the obtained mixed material is put into a twin-screw extruder for melt extrusion granulation to obtain the door seal strip particles made of SEBS thermoplastic elastomer material. Among them, the ratio of the length to the diameter of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C - 220°C, the feeding speed of the twin-screw extruder is 20 Hz, and the main machine speed of the twin-screw extruder is 400 r / min.

[0060] Furthermore, the door seal strip particles obtained in Comparative Example 1 are prepared into a door seal strip and then the performance is tested. The specific test results are shown in Table 1.

[0061] Comparative Example 2

[0062] The door seal strip particles made of polyolefin elastomer (POE) material, by weight parts, include: 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of POE, 0.05 part of antioxidant 1010, 0.05 part of antioxidant 168, 0.1 part of lubricant ethylene bisstearamide (EBS). Among them, the polyolefin elastomer (POE) selects POE-8200 of Dow Chemical Company of the United States.

[0063] The method for preparing the door seal strip particles made of polyolefin elastomer (POE) material includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of POE, 0.05 part of antioxidant 1010, 0.05 part of antioxidant 168, 0.1 part of lubricant ethylene bisstearamide (EBS) into a three-dimensional integrated blender and blending for 4 h. After the 10# white mineral oil is fully absorbed, the obtained mixed material is put into a twin-screw extruder for melt extrusion granulation to obtain the door seal strip particles made of POE material. Among them, the ratio of the length to the diameter of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C - 220°C, the feeding speed of the twin-screw extruder is 20 Hz, and the main machine speed of the twin-screw extruder is 400 r / min.

[0064] Furthermore, the door seal particles obtained in Comparative Example 2 were prepared into door seals and their performance was tested. The specific test results are shown in Table 1.

[0065] Comparative Example 3

[0066] The antibacterial SEBS thermoplastic elastomer (SEBS-1) comprises, by weight: 100 parts of SEBS thermoplastic elastomer, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of methacryloyloxyethyl trimethylammonium chloride, wherein the SEBS thermoplastic elastomer is selected from 250N of Celanese Corporation of the United States.

[0067] The method for preparing an antibacterial SEBS polyolefin elastomer (SEBS-1) comprises: weighing 100 parts of SEBS thermoplastic elastomer, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of methacryloyloxyethyl trimethyl ammonium chloride in a three-dimensional mixer and mixing them thoroughly for 30 minutes, taking out the obtained mixture and putting it into a twin-screw extruder that has been heated in advance for melt extrusion granulation to obtain an antibacterial SEBS thermoplastic elastomer, named SEBS-1. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0068] The method for preparing door seal particles of SEBS thermoplastic elastomer (SEBS-1) material with antibacterial properties comprises: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of SEBS-1, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 parts of lubricant EBS in a three-dimensional blender, and blending for 4 hours. After the 10# white mineral oil is fully absorbed, the obtained mixture is put into a twin-screw extruder for melt extrusion granulation to obtain door seal particles of SEBS-1 thermoplastic elastomer material. The aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C-220°C, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0069] Furthermore, the door seal particles obtained in Comparative Example 3 were prepared into door seals and their performance was tested. The specific test results are shown in Table 2.

[0070] Comparative Example 4

[0071] The difference between Comparative Example 4 and Comparative Example 3 is that the door seal particles are made of SEBS thermoplastic elastomer (SEBS-2) with oil resistance and water vapor barrier, and the specific preparation process is as follows.

[0072] The oil- and grease-resistant and water vapor barrier type SEBS thermoplastic elastomer (SEBS-2), by weight parts, includes: 100 parts of SEBS thermoplastic elastomer, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of polydimethylsiloxane. Among them, the SEBS thermoplastic elastomer is selected from 250N produced by Celanese Corporation of the United States.

[0073] The method for preparing the oil- and grease-resistant and water vapor barrier type SEBS thermoplastic elastomer (SEBS-2) includes: weighing 100 parts of SEBS thermoplastic elastomer, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of polydimethylsiloxane in a three-dimensional mixer and fully mixing for 30 min. Then, take out the obtained mixed material and put it into a twin-screw extruder that has been preheated in advance for melt extrusion granulation to obtain the oil- and grease-resistant and water vapor barrier type SEBS thermoplastic elastomer, named SEBS-2. Among them, the length-diameter ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C - 220°C, the feeding speed of the twin-screw extruder is 20 Hz, and the main machine rotation speed of the twin-screw extruder is 400 r / min.

[0074] The method for preparing the door seal strip particles made of the oil- and grease-resistant and water vapor barrier type SEBS thermoplastic elastomer (SEBS-2) includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of SEBS-2, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 part of lubricant ethylene bisstearamide (EBS) in a three-dimensional blender and blending for 4 h. After the 10# white mineral oil is fully absorbed, put the obtained mixed material into a twin-screw extruder for melt extrusion granulation to obtain the door seal strip particles made of SEBS-2 thermoplastic elastomer. Among them, the length-diameter ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150°C - 220°C, the feeding speed of the twin-screw extruder is 20 Hz, and the main machine rotation speed of the twin-screw extruder is 400 r / min.

[0075] Further, the door seal strip particles obtained in Comparative Example 4 are made into a door seal strip and then its performance is tested. The specific test results are shown in Table 2.

[0076] Comparative Example 5

[0077] The antibacterial POE polyolefin elastomer (POE-1) includes, by weight: 100 parts of POE polyolefin elastomer, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of methacryloyloxyethyl trimethyl ammonium chloride. Among them, the POE polyolefin elastomer uses POE-8200 produced by Dow Chemical Company of the United States, with a molecular weight distribution PDI of about 2.6 and a melt index of about 5g / 10min (190°C, 2.16kg).

[0078] The method for preparing an antibacterial POE polyolefin elastomer (POE-1) comprises: weighing 100 parts of POE polyolefin elastomer, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of methacryloyloxyethyl trimethyl ammonium chloride in a three-dimensional mixer and mixing them thoroughly for 30 minutes, taking out the obtained mixture and putting it into a twin-screw extruder that has been heated in advance for melt extrusion granulation to obtain an antibacterial POE polyolefin elastomer, named POE-1. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0079] The method for preparing door seal particles of POE polyolefin elastomer (POE-1) material with antibacterial properties comprises: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of POE-1, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 parts of lubricant EBS in a three-dimensional blender, and blending for 4 hours. After the 10# white mineral oil is fully absorbed, the obtained mixture is put into a twin-screw extruder for melt extrusion granulation to obtain door seal particles of POE-1 material. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0080] Furthermore, the door seal particles obtained in Comparative Example 5 were prepared into door seals and their performance was tested. The specific test results are shown in Table 2.

[0081] Comparative Example 6

[0082] The difference between Comparative Example 6 and Comparative Example 5 is that the door seal particles are made of POE polyolefin elastomer (POE-2) material that is resistant to oil stains and has a water vapor barrier property, and the specific preparation process is as follows.

[0083] The POE polyolefin elastomer (POE-2) with oil resistance and water vapor barrier comprises, by weight: 100 parts of POE, 0.15 parts of di-tert-butyl peroxide (initiator), and 1.5 parts of polydimethylsiloxane, wherein the POE polyolefin elastomer is selected from POE-8200 produced by Dow Chemical Company of the United States.

[0084] The method for preparing a POE polyolefin elastomer (POE-2) with oil resistance and water vapor barrier includes: weighing 100 parts of POE polyolefin elastomer, 0.15 parts of di-tert-butyl peroxide, and 1.5 parts of polydimethylsiloxane in a three-dimensional mixer and mixing them thoroughly for 30 minutes, taking out the obtained mixture and putting it into a twin-screw extruder that has been heated in advance for melt extrusion granulation to obtain a POE polyolefin elastomer with oil resistance and water vapor barrier, named POE-2. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0085] The method for preparing door seal particles of POE polyolefin elastomer (POE-2) material with oil resistance and water vapor barrier includes: weighing 25 parts of 10# white mineral oil, 30 parts of polypropylene K7227H, 25 parts of heavy calcium carbonate, 20 parts of POE-2, 0.05 parts of antioxidant 1010, 0.05 parts of antioxidant 168, and 0.1 parts of lubricant EBS in a three-dimensional integrated blender, and blending for 4 hours. After the 10# white mineral oil is fully absorbed, the obtained mixture is put into a twin-screw extruder for melt extrusion granulation to obtain door seal particles of POE-2 material. Among them, the aspect ratio of the twin-screw extruder is 45, the temperature of each zone of the twin-screw extruder is 150℃-220℃, the feeding speed of the twin-screw extruder is 20Hz, and the main engine speed of the twin-screw extruder is 400r / min.

[0086] Furthermore, the door seal particles obtained in Comparative Example 6 were prepared into door seals and their performance was tested. The specific test results are shown in Table 2.

[0087] Table 1

[0088]

[0089] Table 2

[0090]

[0091] Table 3

[0092]

[0093] As can be seen from the comparison between Table 1 and Table 3, the product performance indicators of the door seals prepared in Examples 1-3 and Comparative Examples 1-6 of the present invention, such as density, melt flow rate, hardness, tensile strength, and elongation at break, all meet the standards of each index. This shows that the door seals prepared in Examples 1-3 of the present invention have excellent performance and can be applied in practice. Further, by comparing the data in Example 1 and Comparative Example 1, it can be found that after replacing SEBS with EPOE completely, all the indicators of the prepared door seal particles show an upward trend, indicating that the strategy of using EPOE to replace SEBS to prepare door seals is feasible. Further, by comparing Example 1 with Comparative Example 2, it can be seen that the performance of the door seals prepared with EPOE can be comparable to that of the door seals prepared with POE. However, POE is a copolymer of ethylene and α-olefins (such as 1-octene), while EPOE in the present invention is an ethylene polymer, which has a lower cost compared to POE and is expected to replace POE materials to prepare door seals. Furthermore, compared with POE, EPOE has a higher degree of branching and is more easily graft-modified. Depending on the grafted substances, different properties can be imparted to the door seal particles, such as unique properties like antibacterial property, oil resistance, and high water vapor barrier property. For example: The antibacterial property of the door seal particles prepared by grafting antibacterial agents into EPOE is significantly improved (such as Examples 1-2 and Comparative Examples 3 and 5); the water vapor barrier property of the door seal particles prepared by grafting polydimethylsiloxane into EPOE is significantly improved, and the performance loss before and after immersion in oil is also reduced (such as Examples 1 and 3 and Comparative Examples 4 and 6), further indicating that grafting different groups of compounds onto EPOE can endow the door seals with unique properties. Furthermore, since EPOE has no unsaturated bonds, compared with SEBS, it can improve the weather resistance, aging resistance of the door seal material and extend the service life.

[0094] Furthermore, the hardness change rates of each example and comparative example were measured and compared. Before the test, the hardness of the door seal before being placed in the refrigerator was measured first, and then the hardness of the door seal after 6 hours in the refrigerator at -25°C, -30°C, -40°C, and -60°C was measured in sequence, and the hardness change rate of the door seal was calculated. The specific test results are shown in Table 4.

[0095] Table 4

[0096]

[0097] As can be seen from Table 4, the door seals made of vinyl polyolefin elastomer provided by the present invention have low-temperature resistance (-25°C to -60°C).

[0098] In summary, when the present invention uses EPOE (vinyl polyolefin elastomer) as a raw material to prepare door seal particles, the following effects are achieved in terms of components.

[0099] (1) In terms of improving flexibility: EPOE can make the products made of door sealant particles more elastic and flexible, which is conducive to the better fitting and sealing of the door sealant and adapting to different usage states.

[0100] (2) In terms of enhancing impact resistance: EPOE helps to improve the overall impact resistance performance of the door sealant. When subjected to external forces such as daily door opening and closing, it is not easy to break or the like.

[0101] (3) Optimizing compatibility: EPOE can improve the compatibility between different components through grafting reactions, making the entire door sealant particle system mix more uniformly and stably, thereby ensuring the performance stability and quality consistency of the door sealant. Specifically, through grafting reactions, EPOE is grafted with functional groups that can chemically react with other components, such as grafting maleic anhydride, etc. When blended with polymers containing reactive groups that can react with it, chemical bonds can be formed at the interface, enhancing the connection between the two and improving compatibility. The grafted EPOE also changes the original surface properties, reducing the interfacial tension between it and other blended components, enabling better dispersion and fusion between different phases, preventing phase separation, and also improving compatibility. The grafted chains can interact with the molecules of other components through intermolecular forces such as van der Waals forces and hydrogen bonds, making the binding between different component molecules closer, facilitating uniform dispersion in the system, and thus also being able to improve compatibility.

[0102] (4) Adjusting hardness: EPOE can appropriately adjust the hardness of the door sealant particles to make it reach a suitable range of softness and hardness, meeting the requirements for touch and sealing effect in actual use.

[0103] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used 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 refrigerator and freezer door seal granule made of vinyl polyolefin elastomer material, characterized in that, In parts by weight, the refrigerator and freezer door seal granules include: 20 - 50 parts of white mineral oil, 10 - 48 parts of polypropylene, 10 - 50 parts of vinyl polyolefin elastomer, 5 - 25 parts of calcium carbonate, 0 - 0.1 part of antioxidant, and 0 - 0.1 part of lubricant; Among them, the degree of branching of the vinyl polyolefin elastomer is 70 - 130 branches / 1000 carbons, the weight-average molecular weight is 77,000 - 521,000, the molecular weight distribution index is 1.5 - 3.0, and the melt index is 1 - 10 g / 10 min.

2. The refrigerator and freezer door seal particles according to claim 1, characterized in that, In parts by weight, the vinyl polyolefin elastomer includes: A grafted product of vinyl polyolefin elastomer, which is obtained by grafting reaction of vinyl polyolefin elastomer with a grafting agent under an initiator; among them, the initiator is 0.1 - 0.2 part, and the grafting agent is 0.5 - 3 parts; The grafting agent is selected from at least one of a compatibilizing monomer, an antibacterial monomer, a hydrophobic monomer, and a sulfide.

3. The refrigerator and the refrigerator door seal strip particles according to claim 1, characterized in that, The degree of branching of the vinyl polyolefin elastomer is 78 - 120 branches / 1000 carbons, the weight-average molecular weight is 84,000 - 424,000, the molecular weight distribution index is 1.8 - 2.8, and the melt index is 2 - 6 g / 10 min.

4. The refrigerator and the freezer door seal particles according to claim 1, characterized in that, The degree of branching of the vinyl polyolefin elastomer is 80 - 110 branches / 1000 carbons, the weight-average molecular weight is 162,000 - 384,000, the molecular weight distribution index is 2.0 - 2.6, and the melt index is 2.5 - 5 g / 10 min.

5. The refrigerator and freezer door seal particles according to claim 1 or 2, characterized in that, The calcium carbonate is selected from at least one of light calcium carbonate, heavy calcium carbonate, and nano calcium carbonate; The polypropylene is selected from at least one of homopolypropylene, block copolymerized polypropylene, and random copolymerized polypropylene; The antioxidant is selected from 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, tris(2,4-di-tert-butylphenyl) phosphite, dibutylhydroxytoluene, butylhydroxyanisole, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-thiobis(6-tert-butyl-m-cresol), pentaerythritol diphosphite distearate, pentaerythritol diphosphite dioctadecyl ester, dilauryl thiodipropionate, distearyl thiodipropionate, tris(nonylphenol) phosphite, and tris(nonylphenyl) phosphite; The lubricant is selected from at least one of stearic acid, calcium stearate, zinc stearate, ethylene bisstearamide, paraffin wax, polyethylene wax, oxidized polyethylene wax, fatty acid ester, pentaerythritol stearate, montan wax, silicone oil, magnesium stearate, barium stearate, N,N'-ethylenebisoleamide, stearamide, and erucamide.

6. The refrigerator and freezer door seal particles according to claim 2, characterized in that, The initiator is a peroxide, and the peroxide is selected from at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butyl peroxy-2-ethylhexyl carbonate.

7. The refrigerator and freezer door seal granules according to claim 6, characterized in that, The compatible monomer is selected from at least one of maleic anhydride, methacrylic acid, acrylic acid, itaconic acid, fumaric acid, glycidyl methacrylate, methyl methacrylate, dibutyl fumarate, 2-hydroxyethyl methacrylate, dibutyl maleate, and diethyl maleate; The antibacterial monomer is selected from quaternary ammonium salts, and the quaternary ammonium salts are selected from at least one of methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, dimethyldiallyl ammonium chloride, methacryloyloxyethyl benzyl dimethyl ammonium chloride, and methacryloyloxyethyl-m-chlorobenzyl-dimethyl ammonium chloride; The hydrophobic monomer is selected from methyl-vinyl siloxane.

8. A preparation method of refrigerator and freezer door seal granules made of vinyl polyolefin elastomer material as described in any one of claims 1-7, characterized in that, The preparation method includes: Step (1): Blending white mineral oil, polypropylene, vinyl polyolefin elastomer, calcium carbonate, antioxidant, and lubricant to obtain a mixed material; Step (2): Feeding the mixed material into a twin-screw extruder for extrusion granulation to obtain door seal strip particles made of vinyl polyolefin elastomer material.

9. The preparation method according to claim 8, wherein Step (1) further includes: adding an initiator and a grafting agent; Among them, in the presence of the initiator, after the grafting agent and the vinyl polyolefin elastomer undergo a grafting reaction to form a grafting product of the vinyl polyolefin elastomer, it is then blended with the white mineral oil, polypropylene, calcium carbonate, antioxidant, and lubricant to obtain a mixed material.

10. A door seal, characterized in that, Prepared from the door seal strip particles made of vinyl polyolefin elastomer material according to any one of claims 1-7.

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