Rubber sleeve and method for manufacturing the same, refrigerator door seal

Abstract

The present application relates to the technical field of plastic forming, and provides a rubber sleeve, a preparation method thereof and a refrigerator door seal, the rubber sleeve is obtained by extruding a mixture of polyvinyl chloride resin as a main body resin and a toughening agent and a lubricant after microwave treatment; the toughening agent is selected from nitrile rubber; and the lubricant includes acrylate and oxidized polyethylene wax; by adopting the microwave crosslinking mode, using nitrile rubber as the toughening agent and acrylate as the lubricant, under the action of microwaves, a micro-crosslinking network can be formed between polyvinyl chloride and powder nitrile rubber, within a controllable microwave crosslinking time range, the present application can greatly improve the tensile strength and aging resistance of the material, and the microwave action and the formed micro-crosslinking structure make the combination between acrylate and polyvinyl chloride resin more compact, so that the plasticizing system effect of acrylate can be fully utilized, and the material performance is further improved.

Description

Technical Field

[0001] This invention relates to the field of plastic molding technology, and in particular to rubber sleeves and their preparation methods, and refrigerator door seals. Background Technology

[0002] Refrigerator door seals mainly consist of two parts: a rubber sleeve and a magnetic strip. A rubber sleeve with excellent and durable sealing performance plays a crucial role in keeping the refrigerator in a low-energy-consumption state. However, in practical applications, it has been found that rubber sleeve structures made primarily of soft polyvinyl chloride (PVC) resin are difficult to maintain their sealing performance over long-term use. The main reasons for this are aging, deformation, and migration of functional components from the rubber sleeve.

[0003] To improve the above situation, the raw material composition of the sleeve can be optimized, for example, by adding more functional additives for compounding, or by improving performance through chemical modification. However, functional additives and chemically modified formulations are very prone to causing appearance defects during sleeve extrusion molding, such as surface pits, pinholes, uneven thickness, and broken edges.

[0004] Therefore, this invention is proposed. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the present invention proposes a rubber sleeve that is resistant to aging, not easily deformed, has low component migration rate, and has excellent appearance.

[0006] This invention also proposes a method for preparing a rubber sleeve, which is simple, easy to implement, and environmentally friendly.

[0007] The present invention also proposes a refrigerator door seal that enables the refrigerator to maintain low energy consumption operation.

[0008] In a first aspect, the present invention provides a rubber sleeve, which is obtained by extrusion molding after microwave treatment of a mixture consisting of polyvinyl chloride resin as the main resin, toughening agent and lubricant.

[0009] The polyvinyl chloride resin includes high-gloss polyvinyl chloride and matte polyvinyl chloride;

[0010] The toughening agent is selected from nitrile rubber;

[0011] The lubricant includes acrylate and oxidized polyethylene wax.

[0012] According to the adhesive sleeve provided by the present invention, the power of the microwave is 600~800W, and the microwave treatment time is 1~3min.

[0013] According to the rubber sleeve provided by the present invention, the mass percentage of acrylonitrile in the nitrile rubber is 30-35%.

[0014] According to the rubber sleeve provided by the present invention, the lubricant further includes ethylene bis-stearamide.

[0015] According to the rubber sleeve provided by the present invention, the mixture further includes a first plasticizer and a second plasticizer, wherein the first plasticizer includes a polyester plasticizer and the second plasticizer includes a linear trimellitic acid trialkyl ester.

[0016] According to the adhesive sleeve provided by the present invention, the high-gloss polyvinyl chloride accounts for 80-90% of the mass of the polyvinyl chloride resin.

[0017] According to the rubber sleeve provided by the present invention, the mixture comprises, by weight, 35-40 parts of polyvinyl chloride resin, 27-32 parts of a first plasticizer, 4-6 parts of a second plasticizer, 20-25 parts of a reinforcing agent, 1-3 parts of a toughening agent, 2-3 parts of a heat stabilizer, 1.5-2 parts of a lubricant, 0.2-0.3 parts of an antioxidant, and 0.2-0.3 parts of a weathering agent.

[0018] According to the rubber sleeve provided by the present invention, the reinforcing agent is selected from heavy calcium carbonate;

[0019] The heat stabilizer is selected from calcium-zinc composite heat stabilizers;

[0020] The antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 3114;

[0021] The weathering agent is selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0022] Secondly, the present invention also provides a method for preparing the rubber sleeve as described above, comprising: mixing polyvinyl chloride resin as the main resin with toughening agent and lubricant, and then extruding it after microwave treatment.

[0023] Thirdly, the present invention also provides a refrigerator door seal, comprising the rubber sleeve as described above or the rubber sleeve prepared by the preparation method described above.

[0024] According to the present invention, a rubber sleeve and its preparation method, as well as a refrigerator door seal, are achieved through microwave crosslinking. Using nitrile rubber as a toughening agent and acrylate as a lubricant, a micro-crosslinked network can be formed between polyvinyl chloride (PVC) and powdered nitrile rubber under microwave irradiation. Within a controllable microwave crosslinking time range, the present invention can significantly improve the tensile strength and aging resistance of the material. Furthermore, acrylate, as a special thermoplastic elastomer, easily entangles with PVC resin molecules under the action of a twin-screw extruder, promoting plasticization and improving the processing performance of the rubber compound. The microwave irradiation and the resulting micro-crosslinked structure further enhance the material's performance. This process strengthens the bond between acrylate and PVC resin, allowing for full utilization of the acrylate's plasticizing system. It promotes the fusion of plasticizers, reinforcing agents, and the resin matrix, reduces PVC resin degradation, and helps improve material performance. During the extrusion stage, the plasticizing effect promotes particle melting, preventing incomplete extrusion and resulting in poor appearance. Simultaneously, the acrylate exhibits a die expansion effect during extrusion, quickly building pressure in the die and maintaining good extrusion stability. Furthermore, subsequent microwave treatment further strengthens the physical bonds between acrylate and PVC, further enhancing material performance.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0026] The embodiments of the present invention will be described in further detail below with reference to examples. These examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0027] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0028] In a specific embodiment of the present invention, a rubber sleeve is first provided, which is obtained by extrusion molding after microwave treatment of a mixture consisting of polyvinyl chloride resin as the main resin, toughening agent and lubricant.

[0029] The polyvinyl chloride resin includes high-gloss polyvinyl chloride and matte polyvinyl chloride;

[0030] The toughening agent is selected from nitrile rubber;

[0031] The lubricant includes acrylate and oxidized polyethylene wax.

[0032] Research has found that, in order to maintain the sealing performance of rubber sleeve structures made primarily of flexible polyvinyl chloride (PVC) resin during long-term use, introducing micro-crosslinked structures into the resin system to improve the density and mechanical properties of the rubber sleeve material, and thereby constraining the functional additives and reducing their migration rate, is a feasible solution. To avoid the defects of traditional chemical crosslinking, such as strong odor and environmental unfriendliness, as well as poor appearance during rubber sleeve extrusion molding, this invention adopts microwave crosslinking, using nitrile rubber as a toughening agent and acrylate as a lubricant. Under microwave action, PVC and powdered nitrile rubber can react to form a micro-crosslinked network. Within a controllable microwave crosslinking time range, this invention can significantly improve the tensile strength and aging resistance of the material. At the same time, compared with the traditional chemical crosslinking method that adds initiators, it is more convenient, the reaction degree is more controllable, there are no by-products, and it is more environmentally friendly.

[0033] Furthermore, as a special thermoplastic elastomer, acrylate easily entangles with PVC resin molecules under the action of a twin-screw extruder, promoting plasticization and improving the processing performance of the compound. The microwave action and the resulting micro-crosslinked structure further strengthen the bond between acrylate and PVC resin, thus fully utilizing the plasticizing system of acrylate to promote the fusion between plasticizers, reinforcing agents, and resin matrix. Rapid plasticization also reduces PVC screw residence time, effectively minimizing PVC resin degradation and improving material properties. During the extrusion stage, the plasticizing effect of acrylate promotes particle melting, preventing incomplete extrusion and resulting in poor appearance. Additionally, acrylate exhibits a die expansion effect during extrusion, quickly building pressure in the die and maintaining good extrusion stability of the sleeve. Furthermore, under subsequent microwave action, the physical bond between acrylate and PVC becomes even stronger, further enhancing material properties.

[0034] Preferably, the mass ratio of the polyvinyl chloride resin to the nitrile rubber is (35~40):(1~3).

[0035] Preferably, the mass ratio of the polyvinyl chloride resin to the acrylate is (35~40):(0.5~1).

[0036] In some specific embodiments of the present invention, the power of the microwave is 600~800W, and the microwave processing time is 1~3min.

[0037] Research has found that the intensity of microwave treatment directly affects the state of the extruded sleeve during the present invention. If the microwave power is high, the cross-linking reaction will occur too rapidly, resulting in inconsistent reaction levels within the system. If the microwave power is low, the microwave cross-linking time will be prolonged, affecting production efficiency. If the microwave time is too long, over-cross-linking is also likely, while if the microwave time is too short, the improvement on the appearance of the sleeve will be insignificant.

[0038] In some specific embodiments of the present invention, the acrylonitrile mass percentage of the nitrile rubber is 30-35%.

[0039] Preferably, the nitrile rubber is in the form of powder.

[0040] The mass content of acrylonitrile in the nitrile rubber affects the elongation at break and the elongation at break after aging of the present invention. Specifically, the higher the mass of acrylonitrile in the nitrile rubber, the higher the initial and aged elongation at break; conversely, the lower the mass of acrylonitrile in the nitrile rubber, the lower the initial and aged elongation at break.

[0041] In some specific embodiments of the present invention, the lubricant further includes ethylene bis-stearamide.

[0042] Oxidized polyethylene wax (external lubricant) has high polarity, which can improve the dispersion of reinforcing agent powder in PVC resin matrix, improve the material demolding effect, and reduce extrusion resistance. However, if its addition is too low, the extrusion of the sleeve will be unstable, and uneven thickness or even edge breakage may occur.

[0043] Ethylene bis-stearamide (internal lubricant) plays a crucial role in dispersing the reinforcing agent; uneven dispersion can lead to pitting on the appearance of the rubber sleeve.

[0044] In some specific embodiments of the present invention, the lubricant is a combination of oxidized polyethylene wax, ethylene bis-stearamide and acrylate.

[0045] In some specific embodiments of the present invention, the acid value of the oxidized polyethylene wax is 15~20 mgKOH / g.

[0046] In some specific embodiments of the present invention, the molecular weight of the acrylate is 250 × 10⁻⁶. 4 g / mol ~300×10 4 g / mol.

[0047] In some specific embodiments of the present invention, the mass ratio of acrylate, oxidized polyethylene wax and ethylene bis-stearamide in the lubricant is (0.8~1):(0.3~0.5):(0.2~0.3).

[0048] In some specific embodiments of the present invention, the mixture further includes a first plasticizer and a second plasticizer, wherein the first plasticizer includes a polyester plasticizer and the second plasticizer includes a linear trimellitic acid trialkyl ester.

[0049] The structural formula of linear trimellitic acid trialkyl ester is as follows:

[0050] ;

[0051] Wherein, R is a straight-chain alkyl group, and the number of C atoms on R is 8 to 10.

[0052] Studies have found that the benzene ring in the linear trimellitic acid trialkyl ester molecule gives it good thermal stability and low volatility, and it can maintain a good plasticizing effect at both high and low temperatures, thus ensuring good resilience of the rubber sleeve at both high and low temperatures.

[0053] In some specific embodiments of the present invention, the polyester plasticizer accounts for more than or equal to 50% of the total plasticizer;

[0054] In some specific embodiments of the present invention, the polyester plasticizer is adipic acid polyester;

[0055] In some specific embodiments of the present invention, the molecular weight of the adipic acid polyester is 1900~2100 g / mol;

[0056] In some specific embodiments of the present invention, the linear trimellitic trialkyl ester is trimellitic trioctyl / decyl trimellitic ester (CAS: 90218-76-1).

[0057] In some specific embodiments of the present invention, the mass ratio of the first plasticizer to the second plasticizer is (27~32):(4~6).

[0058] In some specific embodiments of the present invention, the mass ratio of the polyvinyl chloride resin to the first plasticizer is (35~40):(27~32).

[0059] In some specific embodiments of the present invention, the high-gloss polyvinyl chloride accounts for 80-90% of the mass of the polyvinyl chloride resin.

[0060] By combining high-gloss and matte PVC, along with internal and external lubricants, the extrusion stability of the sleeve can be effectively improved, reducing appearance defects such as pits and pinholes. The study found that excessive matte PVC leads to performance degradation, while insufficient matte PVC results in excessively high gloss and a tendency for pinholes in the extruded sleeve. Based on actual test data, the optimal proportion of high-gloss PVC is 80-90% of the total PVC mass.

[0061] The high-gloss and matte PVC used in this invention can be common types in the art.

[0062] Preferably, the high-gloss polyvinyl chloride is a PVC resin with a non-crosslinked molecular chain structure.

[0063] Preferably, the matte polyvinyl chloride refers to a polyvinyl chloride with a cross-linking matting agent added during the polymerization process, the molecular chain having a partially cross-linked structure, and the gel content being 5-20%.

[0064] In some specific embodiments of the present invention, the molecular weight of the high-gloss polyvinyl chloride is 1200~1400.

[0065] In some specific embodiments of the present invention, the molecular weight of the matte polyvinyl chloride is 1200~1400.

[0066] In some specific embodiments of the present invention, the mixture comprises, by weight, 35-40 parts of polyvinyl chloride resin, 27-32 parts of a first plasticizer, 4-6 parts of a second plasticizer, 20-25 parts of a reinforcing agent, 1-3 parts of a toughening agent, 2-3 parts of a heat stabilizer, 1.5-2 parts of a lubricant, 0.2-0.3 parts of an antioxidant, and 0.2-0.3 parts of a weathering agent.

[0067] In some specific embodiments of the present invention, the reinforcing agent is selected from heavy calcium carbonate; preferably, the heavy calcium carbonate is heavy calcium carbonate surface-treated with a coupling agent, and more preferably, the average particle size of the heavy calcium carbonate is <10μm;

[0068] In some specific embodiments of the present invention, the heat stabilizer is selected from calcium-zinc composite heat stabilizers.

[0069] In some specific embodiments of the present invention, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 3114.

[0070] In some specific embodiments of the present invention, the weathering agent is selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

[0071] In a specific embodiment of the present invention, a method for preparing the aforementioned rubber sleeve is also provided, comprising: mixing polyvinyl chloride resin as the main resin with toughening agent and lubricant, and then extruding it after microwave treatment.

[0072] In some specific embodiments of the present invention, the preparation method includes:

[0073] (1) Mix all plasticizer raw materials to obtain plasticizer mixture.

[0074] (2) Mix 30-70% of the plasticizer mixture with the remaining raw materials other than the reinforcing agent in a mixing pot to obtain the first mixture.

[0075] (3) When the first mixture is stirred at high speed to 60~100℃ (the temperature rises during the stirring process and heats up under high speed stirring), the remaining plasticizer mixture is added and mixed evenly to obtain the second mixture.

[0076] (4) After adding the reinforcing agent to the second mixture, continue to stir at high speed to 120~160℃ (the temperature rises during stirring and heats up under high-speed stirring) to obtain the third mixture.

[0077] (5) The third mixture is extruded, hot-cut, and air-cooled through a twin-screw extruder to obtain granules;

[0078] (6) Spread the granules evenly and place them in a microwave oven for microwave cooking. After microwave cooking, let them cool to room temperature to obtain the rubber sleeve material.

[0079] (7) The rubber sleeve raw material is extruded and molded to obtain the rubber sleeve.

[0080] In some specific embodiments of the present invention, the twin-screw extrusion temperature is 140~160℃, the screw length-to-diameter ratio is 28:1 or 25:1, and the screw speed is 50~70rpm.

[0081] In some specific embodiments of the present invention, the extrusion molding temperature is 130~140℃ and the main machine speed is 20~30rpm.

[0082] A specific embodiment of the present invention also provides a refrigerator door seal, comprising the rubber sleeve described above or the rubber sleeve prepared by the method described above. It is particularly suitable for door seal rubber sleeves with complex structures of double or multiple airbags and thin airbag walls (≤0.4mm). Preferably, the airbag wall thickness of the door seal rubber sleeve is less than or equal to 0.4mm.

[0083] The following will provide a detailed description of the rubber sleeve and its preparation method, as well as the refrigerator door seal, based on specific implementation examples of the present invention.

[0084] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels. Information on some of the raw materials is as follows:

[0085] Table 1

[0086]

[0087] Examples 1-6

[0088] This embodiment provides a rubber sleeve for refrigerator door sealing, the raw materials of which are shown in the table below by weight:

[0089] Table 2

[0090]

[0091] This embodiment provides a method for preparing the above-mentioned rubber sleeve, the steps of which are as follows:

[0092] (1) Mix all plasticizer raw materials to obtain plasticizer mixture.

[0093] (2) Mix 50% of the plasticizer mixture with the remaining raw materials other than the reinforcing agent in a mixing pot to obtain the first mixture.

[0094] (3) When the first mixture is stirred at high speed to 80°C, another 50% by weight of plasticizer mixture is added and mixed evenly to obtain the second mixture.

[0095] (4) After adding the reinforcing agent to the second mixture, continue stirring at high speed to 140°C to obtain the third mixture.

[0096] (5) The third mixture is extruded, hot-cut and air-cooled through a twin-screw extruder to obtain granules; wherein the twin-screw extrusion temperature is 150℃, the screw length-to-diameter ratio is 28:1 and the screw speed is 60rpm.

[0097] (6) Spread the granules evenly and place them in a microwave oven for microwave cooking. After microwave cooking, let them cool to room temperature to obtain the rubber sleeve material.

[0098] The microwave parameters in step (6) of each embodiment are shown in the table below.

[0099] Table 3

[0100]

[0101] (7) The rubber sleeve raw material is extruded into a refrigerator door seal rubber sleeve using a conventional refrigerator door seal rubber sleeve extrusion equipment. The extrusion molding temperature is 135℃ and the main machine speed is 25rpm.

[0102] Example 7

[0103] It is basically the same as Example 5, except that the weight of D-1050 is 28 parts and the weight of UN380 is 2 parts.

[0104] Example 8

[0105] It is basically the same as Example 6, except that the weight of the first resin is 26 parts and the weight of the second resin is 10 parts.

[0106] Comparative Example 1

[0107] It is basically the same as Example 1, except that the microwave time is shortened to 0.5 min.

[0108] Comparative Example 2

[0109] It is basically the same as Example 4, except that the microwave time is extended to 5 minutes.

[0110] Comparative Example 3

[0111] It is basically the same as Example 2, except that the amount of P-533J is adjusted to 0.5 parts.

[0112] Comparative Example 4

[0113] It is basically the same as Example 3, except that 610A is not added.

[0114] Comparative Example 5

[0115] It is basically the same as Example 6, except that the second resin is replaced with the first resin by the same mass.

[0116] Test case

[0117] The particles from the examples and comparative examples were injection molded into 2mm thick samples, and then cut into standard test strips using a cutter. The following methods were used to test each property:

[0118] (1) Tensile strength / elongation at break

[0119] According to standard GB / T 1040.1-2018, the average value of 3 groups was taken.

[0120] (2) Tensile strength retention rate and elongation at break retention rate after aging

[0121] The standard test specimens were placed in a high-temperature chamber at 120±2℃ for 120 hours, and then placed at room temperature for 24 hours before testing various properties. The retention rate was calculated as (performance after aging / performance before aging) × 100%. The average value of the three test groups was taken.

[0122] (3) Cold resistance test

[0123] Take a 150mm standard test strip, mark 100mm in the middle, and then place it in a constant temperature bath at -30℃. After 6 hours, take it out and test the length of the mark within 1 minute. The reduction rate = (length before experiment - length after experiment) / length before experiment × 100%. Take the average value of 3 groups.

[0124] (4) Heat resistance test

[0125] Take a 150mm standard test strip, mark 100mm in the middle, and then place it in a constant temperature bath at 70℃. After 6 hours, take it out and test the length of the mark within 1 minute. The reduction rate = (length before experiment - length after experiment) / length before experiment × 100%. Take the average value of 3 groups.

[0126] (5) Migration testing

[0127] Cut a sample measuring 50mm × 10mm × 2mm (dimensional deviation ±0.3mm), place it in a desiccator for 24 hours, weigh it, and record the weight as M1. Then sandwich it between two standard HIPS plates to obtain the test sample. Place the test sample horizontally in an oven, apply a 1.1kg weight on it, and maintain the oven temperature at 70±2℃ for 72 hours. After 72 hours, remove the sample and separate it from the standard HIPS plates. Cool the sample to room temperature and record the weight as M2. Molecular mobility = (M1-M2) / M1 × 100%. Take the average value of 3 sets of tests.

[0128] (6) Compression recovery rate

[0129] The door seal was tested after being placed at room temperature for 48 hours. Two 100mm door seals were taken, and their free height was measured. The seals were then tightened to 60% of their free height (which can also be understood as compressing the cross-section) and placed in an environment of 50℃±3℃ for 96 hours. After removing the clamps, the seals were placed at room temperature for 2 hours and their free height was measured again. The compression recovery rate was calculated as (free height after the experiment / free height before the experiment) × 100%.

[0130] (7) Appearance evaluation

[0131] Each example and comparative example particle was continuously extruded into a door seal extruder at a rate of 10 kg under the same process conditions. The last 300 mm of the extruded door seal was cut off and visually evaluated. Any defects such as surface pits, pinholes, uneven thickness, or broken edges were considered NG, while the rest were considered OK.

[0132] The test results are as follows:

[0133] Table 4

[0134]

[0135] Table 5

[0136]

[0137] As can be seen from the above data, compared with Example 1 and Comparative Example 1, the crosslinking time is too short to generate a sufficient winding structure, the material strength and elongation at break are relatively low, and the performance deteriorates significantly after aging.

[0138] Compared with Example 4 and Comparative Example 2, although the strength was improved due to the excessive crosslinking time, the elongation decreased significantly due to the excessive crosslinking. At the same time, the excessive crosslinking formed a gel, which did not melt during the extrusion process, resulting in poor appearance.

[0139] Compared with Example 2 and Comparative Example 3, the amount of acrylate lubricant was reduced, the overall plasticization of the material during processing was insufficient, and the overall performance was significantly reduced. At the same time, the unstable extrusion of the door seal strip led to poor edge breaking.

[0140] Compared with Example 3 and Comparative Example 4, if oxidized polyethylene wax is not added, uneven thickness will occur during the door seal extrusion process.

[0141] As can be seen from Example 6 and Comparative Example 5, if matte PVC resin is not added, the performance will not be affected, but will be improved. However, the excessive gloss during the extrusion process leads to obvious appearance defects.

[0142] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. A rubber sleeve, characterized in that, The sleeve is obtained by extrusion molding after microwave treatment of a mixture consisting of polyvinyl chloride resin as the main resin, toughening agent, lubricant, first plasticizer and second plasticizer; The polyvinyl chloride resin includes high-gloss polyvinyl chloride and matte polyvinyl chloride; the high-gloss polyvinyl chloride is a PVC resin with no cross-linked molecular chain structure, and the matte polyvinyl chloride refers to a PVC resin in which a cross-linking matting agent is added during the polymerization process, resulting in a partially cross-linked molecular chain structure, with a gel content of 5-20%; the high-gloss polyvinyl chloride accounts for 80-90% of the total mass of the polyvinyl chloride resin. The toughening agent is selected from nitrile rubber; The lubricant comprises acrylate thermoplastic elastomer and oxidized polyethylene wax; The mass ratio of the polyvinyl chloride resin to the acrylate thermoplastic elastomer is (35~40):(0.8~1). The microwave power is 600~800W, and the microwave processing time is 1~3min.

2. The rubber sleeve according to claim 1, characterized in that, The first plasticizer includes polyester plasticizers, and the second plasticizer includes trialkyl trimellitate.

3. The rubber sleeve according to claim 1, characterized in that, The mass ratio of the polyvinyl chloride resin to the nitrile rubber is (35~40):(1~3).

4. The rubber sleeve according to claim 1, characterized in that, In the nitrile rubber, the mass percentage of acrylonitrile is 30-35%.

5. The rubber sleeve according to claim 1, characterized in that, The lubricant also includes ethylene bis-stearamide.

6. A rubber sleeve, characterized in that, The rubber sleeve is obtained by extruding a mixture after microwave treatment; By weight, the mixture comprises: 35-40 parts of polyvinyl chloride resin, 27-32 parts of a first plasticizer, 4-6 parts of a second plasticizer, 20-25 parts of a reinforcing agent, 1-3 parts of a toughening agent, 2-3 parts of a heat stabilizer, 1.5-2 parts of a lubricant, 0.2-0.3 parts of an antioxidant, and 0.2-0.3 parts of a weathering agent; The polyvinyl chloride resin includes high-gloss polyvinyl chloride and matte polyvinyl chloride; the high-gloss polyvinyl chloride is a PVC resin with no cross-linked molecular chain structure, and the matte polyvinyl chloride refers to a PVC resin in which a cross-linking matting agent is added during the polymerization process, resulting in a partially cross-linked molecular chain structure, with a gel content of 5-20%; the high-gloss polyvinyl chloride accounts for 80-90% of the total mass of the polyvinyl chloride resin. The toughening agent is selected from nitrile rubber; The lubricant comprises acrylate thermoplastic elastomer and oxidized polyethylene wax; The mass ratio of the polyvinyl chloride resin to the acrylate thermoplastic elastomer is (35~40):(0.8~1). The microwave power is 600~800W, and the microwave processing time is 1~3min.

7. The rubber sleeve according to claim 6, characterized in that, The mass ratio of the polyvinyl chloride resin to the nitrile rubber is (35~40):(1~3).

8. The rubber sleeve according to claim 6, characterized in that, In the nitrile rubber, the mass percentage of acrylonitrile is 30-35%.

9. The rubber sleeve according to claim 6, characterized in that, The lubricant also includes ethylene bis-stearamide.

10. The rubber sleeve according to claim 6, characterized in that, The first plasticizer includes polyester plasticizers, and the second plasticizer includes trialkyl trimellitate.

11. The rubber sleeve according to any one of claims 6 to 10, characterized in that, The reinforcing agent is selected from heavy calcium carbonate; The heat stabilizer is selected from calcium-zinc composite heat stabilizers; The antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, and antioxidant 3114; The weathering agent is selected from 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

12. A method for preparing the rubber sleeve according to any one of claims 1 to 11, characterized in that, include: The mixture is microwave-treated and then extruded into shape.

13. A refrigerator door seal, characterized in that, Includes the rubber sleeve as described in any one of claims 1 to 11 or the rubber sleeve prepared by the preparation method described in claim 12.

Images