Reclaimed material-containing rubber composition for sealing ring and application thereof

Abstract

The invention provides a reclaimed material-containing rubber composition for a sealing ring and application of the reclaimed material-containing rubber composition. The rubber composition for the sealing ring comprises specific parts of solid nitrile rubber, blocky regenerated nitrile rubber, powdery regenerated nitrile rubber, chlorosulfonated polyethylene rubber, liquid nitrile rubber, carbon black, microcrystalline wax, an anti-aging system and a vulcanization system. According to the rubber composition for the sealing ring, the mass ratio of the regenerated nitrile rubber is high, so that the cost is lower, and through reasonable matching of all the components, the rubber composition for the sealing ring has the advantages of being short in vulcanization time, excellent in mechanical property, low in cost and the like on the premise that the mass ratio of the regenerated nitrile rubber is high. And the material has the characteristics of excellent aging resistance and low compression set, and is suitable for being applied to preparation of loudspeaker sealing rings.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and in particular relates to a rubber composition for a sealing ring containing recycled materials and application thereof. Background Art

[0002] As a polar rubber, the desulfurization process of nitrile rubber (NBR) is very complicated. Its waste rubber raw materials mainly come from waste nitrile rubber edges, waste nitrile gloves and other waste rubbers with nitrile vulcanized rubber as the main body. Before the recycling technology is mature, the main treatment method is landfill or incineration, which has great environmental pollution and safety hazards.

[0003] With the development of recycling technology, recycled nitrile rubber has gradually been used in the market to replace some NBR, which can not only reduce environmental pollution, but also reduce raw material costs and production costs. At present, recycled rubber itself has the following disadvantages: (1) Poor mechanical properties. Compared with NBR, its tensile strength after vulcanization decreases significantly; (2) Poor aging resistance, and its performance decreases significantly after long-term use; (3) Poor elasticity. Recycled rubber is a plastic material obtained by processing vulcanized rubber. It has good plasticity and poor elasticity. It cannot recover to its original elasticity level after vulcanization. The existing technology usually blends NBR raw rubber with recycled nitrile rubber to improve the elasticity and mechanical properties of the recycled rubber and reduce permanent deformation.

[0004] For example, CN102731864A discloses a nitrile regenerated rubber sealing ring material, which is made of the following raw materials in parts by weight: 48-52 parts of nitrile rubber, 20-25 parts of nitrile regenerated rubber, 1.5-2 parts of antioxidant SP, 0.8-1 parts of antioxidant BLE, 0.8-1 parts of stearic acid, 0.5-0.8 parts of sulfur powder, 1-1.2 parts of palm wax, 5-6 parts of zinc oxide, 1-1.2 parts of processing aid WB16, 60-65 parts of carbon black N550, 30-35 parts of carbon black N330, 35-40 parts of methyl pentachlorostearate, 1-1.5 parts of accelerator TMTD, 1-1.5 parts of accelerator TETD, and 1-1.5 parts of accelerator DM. 1.5-2 parts, nano calcium carbonate 2-4 parts, alkyl resorcinol formaldehyde resin 2-3 parts, maleic anhydride 2-3 parts, plasticizer 2-4 parts. The invention uses recycled nitrile rubber as raw material, optimizes the formula of raw materials, and prepares nitrile recycled rubber sealing ring materials with excellent performance, good high temperature resistance and high hardness, thereby saving costs. However, the proportion of nitrile recycled rubber in the formula of the nitrile recycled rubber sealing ring material provided by the invention is low, the cost savings are limited, and the aging resistance is poor, and the use requirements cannot be met after blending. In addition, the addition of nitrile recycled rubber will increase the permanent deformation of the rubber, resulting in a very limited scope of application of the resulting rubber material.

[0005] Therefore, in response to the above problems, it is urgent to develop a rubber composition for sealing rings that has a high proportion of recycled nitrile rubber, low cost, and excellent mechanical properties and aging resistance. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a rubber composition for sealing rings containing recycled materials and applications thereof. The mass proportion of recycled nitrile rubber in the rubber composition for sealing rings is relatively high, and thus the cost is lower. Through the reasonable combination of various components, it also has excellent mechanical properties and aging resistance, and at the same time has low compression permanent deformation, and is suitable for use in speakers.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a rubber composition for a sealing ring containing recycled materials, wherein the rubber composition for a sealing ring comprises the following components in parts by weight:

[0009]

[0010]

[0011] The rubber composition for sealing rings containing recycled materials provided by the present invention, on the one hand, effectively increases the mass proportion of recycled nitrile rubber in the rubber composition for sealing rings by adopting block-shaped recycled nitrile rubber and powder-shaped recycled nitrile rubber, thereby effectively reducing the use of NBR raw rubber, greatly saving costs and reducing pollution to the environment; on the other hand, liquid nitrile rubber (LNBR) is added, which, as a liquid plasticizer and rubber softener, has a similar molecular structure to nitrile rubber, can promote the interface compatibility of solid nitrile rubber, block-shaped recycled nitrile rubber and powder-shaped recycled nitrile rubber, and while playing a volume-increasing role, can also participate in co-crosslinking during the vulcanization process of the rubber material, improve the degree of vulcanization and crosslinking density, form a three-dimensional crosslinking network, and thus help to improve the tensile strength of the rubber composition for sealing rings obtained in the end, and reduce its compression permanent deformation; in addition, a specific number of chlorosulfonated polyethylene rubber (CSM) is added, which is coordinated with the anti-aging system to effectively improve the aging properties of the rubber composition for sealing rings, such as heat-oxidative aging resistance, ultraviolet aging resistance and ozone aging resistance.

[0012] In summary, the rubber composition for sealing rings containing recycled materials provided by the present invention has high mechanical properties and aging resistance while saving costs, and meets the use requirements of sealing rings for speakers.

[0013] In the present invention, the sources of the block-shaped regenerated nitrile rubber and the powder-shaped regenerated nitrile rubber include waste rubber mainly composed of nitrile vulcanized rubber, such as waste nitrile rubber edges and waste nitrile gloves, and the desulfurization process adopted is atmospheric pressure twin-screw continuous desulfurization, and the process energy consumption is about 800-830kw·h / t, which is much lower than the process energy consumption of synthetic NBR rubber (>2000kw·h / t); in addition, the mixing and vulcanization time of the block-shaped regenerated nitrile rubber and the powder-shaped regenerated nitrile rubber is greatly shortened, which can further reduce the energy consumption in the processing process.

[0014] Preferably, the Mooney viscosity of the solid nitrile rubber is 45 to 65, for example, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63 or 65.

[0015] Preferably, the mass percentage of acrylonitrile in the solid nitrile rubber is 28-33%, for example, 28%, 29%, 30%, 31%, 32% or 33%.

[0016] In the present invention, the solid nitrile rubber with the above-mentioned specific acrylonitrile content is selected to ensure a faster vulcanization rate and good processing and forming properties, and to ensure moderate elasticity, strength and oil resistance. At the same time, it has similar polarity and solubility parameters with CSM, block recycled NBR, powdered recycled NBR and LNBR, which can ensure better compatibility of the blending system; illustratively, the solid nitrile rubber can be selected from N2845, N2865 or N3345 of Nandi Company.

[0017] Preferably, the Mooney viscosity of the block-shaped regenerated nitrile rubber is 40-50, for example, 40, 41, 42, 43, 44, 44, 46, 47, 48, 49 or 50, etc.

[0018] Preferably, the mass percentage of ash in the block-shaped recycled nitrile rubber is less than 10%, for example, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1%, etc.

[0019] For example, the block-shaped recycled nitrile rubber can be ZH-RNBR-40A, ZH-RNBR-45A or ZH-RNBR-50A produced by Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0020] Preferably, the Mooney viscosity of the powdered regenerated nitrile rubber is 40-50, for example, 40, 42, 44, 46, 48 or 50.

[0021] Preferably, the mass percentage of ash in the powdered regenerated nitrile rubber is less than 10%, for example, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1%, etc.

[0022] Preferably, the powdered recycled nitrile rubber has a D 50 The particle size is 100 to 250 μm, for example, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm or 250 μm.

[0023] For example, the powdered recycled nitrile rubber can be ZH-RNBR-40A, ZH-RNBR-45A or ZH-RNBR-50A produced by Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0024] Preferably, the Mooney viscosity of the chlorosulfonated polyethylene rubber is 30-60, for example, 30, 35, 40, 45, 50, 55 or 60.

[0025] Preferably, the mass percentage of chlorine in the chlorosulfonated polyethylene rubber is 33-37%, for example, 33%, 34%, 35%, 36% or 37%, etc.; selecting CSM with a higher chlorine content can ensure that its crystallinity is lower, its polarity is stronger, its elasticity, aging resistance and mechanical properties are better, and its compatibility with other components is higher.

[0026] Preferably, the mass percentage of sulfur in the chlorosulfonated polyethylene rubber is 0.8-1.2%, for example, 0.8%, 0.85%, 0.9%, 0.95%, 1%, 1.05%, 1.1%, 1.15% or 1.2%.

[0027] Preferably, the chlorosulfonated polyethylene rubber is a CM40 series chlorosulfonated polyethylene rubber, illustratively including CSM3303, CSM3304 or SM3305.

[0028] Preferably, the Mooney viscosity of the liquid nitrile rubber is 30-50, for example, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 or 50.

[0029] Preferably, the mass percentage of acrylonitrile in the liquid nitrile rubber is 30-34%, for example, 30%, 30.5%, 31%, 31.5%, 32%, 32.5%, 33%, 33.5% or 34%.

[0030] Preferably, the number average molecular weight of the liquid nitrile rubber is 1000-2000, for example, 1000, 1200, 1400, 1600, 1800 or 2000.

[0031] Preferably, the anti-aging system includes antioxidant 4020 and antioxidant RD; the aging resistance of the rubber composition can be further improved.

[0032] Preferably, the vulcanization system comprises 0.8 to 1.6 parts by weight of sulfur (e.g., 0.8 parts by weight, 0.9 parts by weight, 1 parts by weight, 1.2 parts by weight, 1.4 parts by weight or 1.6 parts by weight, etc.), 0.6 to 1.2 parts by weight of vulcanization accelerator TMTD (e.g., 0.6 parts by weight, 0.7 parts by weight, 0.9 parts by weight, 1.1 parts by weight, 1.3 parts by weight, 1.5 parts by weight or 1.6 parts by weight, etc.), and 0.6 to 1.2 parts by weight of vulcanization accelerator DM (e.g., 0.6 parts by weight, 0.7 parts by weight, 0.9 parts by weight, 1.1 parts by weight, 1.3 parts by weight, 1.5 parts by weight or 1.6 parts by weight, etc.).

[0033] Preferably, the rubber composition for sealing ring further includes 0.5 to 2 parts by weight (for example, 0.5 parts by weight, 0.7 parts by weight, 0.9 parts by weight, 1.1 parts by weight, 1.3 parts by weight, 1.5 parts by weight, 1.7 parts by weight, 1.9 parts by weight or 2 parts by weight, etc.) of internal mold release agent; the internal mold release agent is added to reduce the adhesion of the rubber formed in the mold to the mold cavity wall, facilitate demolding, and improve the quality rate and labor production efficiency.

[0034] Preferably, the internal mold release agent includes zinc stearate and calcium stearate.

[0035] Preferably, the rubber composition for sealing ring further includes 1 to 2 parts by weight (for example, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight or 2 parts by weight, etc.) of a deodorant; the deodorant is added to reduce the odor of the recycled nitrile rubber, and its principle is mainly to achieve the deodorizing effect by reacting the volatile sulfides in the recycled nitrile rubber with it to generate non-volatile substances.

[0036] Preferably, the deodorant comprises hydroquinone and salicylic acid.

[0037] In a second aspect, the present invention provides a rubber sheet for a sealing ring containing recycled materials, wherein the rubber sheet for a sealing ring is prepared using the rubber composition for a sealing ring as described in the first aspect.

[0038] Preferably, the thickness of the rubber strip for the sealing ring is 0.2-2 mm, for example, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm or 2 mm.

[0039] In a third aspect, the present invention provides a method for preparing a rubber sheet for a sealing ring containing recycled materials as described in the second aspect, the preparation method comprising: mixing the various materials in the rubber composition for the sealing ring according to specific amounts, and obtaining the rubber sheet for the sealing ring containing recycled materials through mixing, open refining and vulcanization molding.

[0040] Preferably, the vulcanization molding temperature is 170-190°C, for example, 170°C, 172°C, 174°C, 176°C, 178°C, 180°C, 182°C, 184°C, 186°C, 188°C or 190°C, etc.

[0041] Preferably, the vulcanization molding time is 40 to 60 s, for example, 40 s, 42 s, 44 s, 46 s, 48 ​​s, 50 s, 52 s, 54 s, 56 s, 58 s or 60 s.

[0042] In a fourth aspect, the present invention provides an application of the rubber strip for the sealing ring as described in the third aspect in a speaker.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The rubber composition for sealing rings containing recycled materials provided by the present invention comprises specific proportions of solid nitrile rubber, block-shaped recycled nitrile rubber, powdered recycled nitrile rubber, chlorosulfonated polyethylene rubber, liquid nitrile rubber, carbon black, microcrystalline wax, an anti-aging system and a vulcanization system. The recycled nitrile rubber in the rubber composition for sealing rings accounts for a high proportion by mass, and thus the cost is lower. Moreover, through the reasonable combination of various components, the rubber composition for sealing rings also has the characteristics of short vulcanization time, excellent mechanical properties and excellent aging resistance, and low compression permanent deformation, and is suitable for use in speakers;

[0045] (2) The rubber composition for sealing rings containing recycled materials provided by the present invention has a vulcanization rate of 30 to 40s, a tensile strength of 12 to 15MPa, an elongation at break of 400 to 600%, and a compression set of less than 12%. After aging at 120°C for 144h, the change rates of tensile strength and tensile modulus are both less than 15%, and there is no cracking after aging for three days at 40°C and 50pphm ozone conditions, which meets the use requirements. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0047] Some of the raw material information involved in the following specific implementation is as follows:

[0048] (1) Solid nitrile rubber

[0049] N2845: Mooney viscosity is 45, the mass percentage of acrylonitrile is 28%, purchased from Nandi Company;

[0050] N2865: Mooney viscosity is 65, the mass percentage of acrylonitrile is 28%, purchased from Nandi Company;

[0051] N3345: Mooney viscosity is 45, mass percentage of acrylonitrile is 33%, purchased from Nandi Company.

[0052] (2) Block recycled nitrile rubber

[0053] ZH-RNBR-40A: Mooney viscosity is 44, ash content is 5.5%, purchased from Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0054] ZH-RNBR-45A: Mooney viscosity is 46, ash content is 5.9% by mass, purchased from Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0055] ZH-RNBR-50A: Mooney viscosity is 49, ash content is 4.3% by mass, purchased from Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0056] (3) Powdered recycled nitrile rubber

[0057] ZH-RNBR-10040A: Mooney viscosity is 44, ash content is 5.5% by mass, particle size is 100-150 μm, purchased from Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.);

[0058] ZH-RNBR-25050A: Mooney viscosity is 49, ash content is 4.3% by mass, particle size is 100-150 μm, purchased from Jiangsu Zhonghong Environmental Protection Technology Co., Ltd.

[0059] (4) Chlorosulfonated polyethylene rubber

[0060] CSM3303: Mooney viscosity is 35, the mass percentage of chlorine is 35%, the mass percentage of sulfur is 1%, purchased from Guangzhou Lida Rubber Raw Materials Trading Co., Ltd.;

[0061] CSM3304: Mooney viscosity is 45, the mass percentage of chlorine is 35%, the mass percentage of sulfur is 1%, purchased from Guangzhou Lida Rubber Raw Materials Trading Co., Ltd.;

[0062] CSM3305: Mooney viscosity is 55, the mass percentage of chlorine is 36%, and the mass percentage of sulfur is 1%. It was purchased from Guangzhou Lida Rubber Raw Materials Trading Co., Ltd.

[0063] (5) Liquid nitrile rubber

[0064] Liquid nitrile rubber-40: Mooney viscosity is 40, mass percentage of acrylonitrile is 35%, number average molecular weight is 1500, purchased from Lanzhou Petrochemical.

[0065] Examples 1 to 11 and Comparative Examples 1 to 8

[0066] Examples 1 to 11 and Comparative Examples 1 to 8 respectively provide a rubber composition for a sealing ring containing recycled materials, and the components included are shown in Table 1 and Table 2;

[0067] In Tables 1 and 2, the dosage units of each component are "parts by weight";

[0068] Table 1

[0069]

[0070]

[0071] Table 2

[0072]

[0073]

[0074] Examples 1 to 11 and Comparative Examples 1 to 8 respectively provide a method for preparing a rubber composition for a sealing ring containing recycled materials, comprising the following steps:

[0075] (1) Blending: solid nitrile rubber, block regenerated nitrile rubber, powdered regenerated nitrile rubber and chlorosulfonated polyethylene rubber are put into an internal mixer, and liquid nitrile rubber, microcrystalline wax, carbon black, heat stabilizer, anti-aging system and internal release agent are added, and the mixture is stirred at 40 r / min at 60° C. for 7 min;

[0076] (2) Mixing: Rapidly cool to 40°C with cold water, add the vulcanization system, and stir at 40 rpm for 3 min;

[0077] (3) Open refining: On the open refining mill, the left and right cutters are turned over three times each, 0.5 mm triangle packing is made five times, and the roller distance is adjusted to 4 mm to produce the sheet;

[0078] (4) Vulcanization molding: The rubber material is vulcanized and molded at 180° C. for 50 seconds to obtain the rubber sheet for the sealing ring containing the recycled material.

[0079] Performance Testing:

[0080] (1) Hot air aging test: The test was conducted in a hot air aging test chamber with the temperature set at 120°C and the time set at 144 h. The tensile strength, elongation at break, and tensile modulus of the rubber before and after aging were tested in accordance with GB / T528-2009. The tensile rate was 200 mm / min.

[0081] (2) UV aging test: The test was carried out in a UV aging test chamber under the following test conditions: UV-a, 340nm, 0.89W / m 2 / nm, 60℃±3℃, test time 72h, refer to GB / T528-2009 to test the tensile strength, elongation at break and tensile modulus of rubber before and after aging, and the tensile rate is 200mm / min.

[0082] (3) Compression set: The test was conducted in accordance with the method specified in GB / T7759.1-2015. The test medium was hot air at a temperature of 70°C for 3 days. The initial compression rate of the compression set was 15%.

[0083] (4) Ozone aging resistance test: The test was conducted in accordance with the method specified in the national standard GB / T7762-2014. The test conditions were: temperature 40°C, ozone concentration 50 pphm, and test time 72 h.

[0084] The rubber compositions for sealing rings provided in Examples 1 to 11 and Comparative Examples 1 to 8 were tested according to the above test method. The test results are shown in Table 3:

[0085] Table 3

[0086]

[0087]

[0088] From the data in Table 3, we can see that:

[0089] The rubber composition for sealing ring containing recycled materials provided in Examples 1 to 11 has the characteristics of short vulcanization time, excellent mechanical properties, excellent aging resistance and low compression permanent deformation under the premise that the proportion of recycled nitrile rubber is relatively high.

[0090] In comparative example 1, no recycled nitrile rubber is added at all, and the proportion of recycled materials is 0%, which is not conducive to the recycling and reuse of waste rubber.

[0091] Comparing the data of Example 2 and Comparative Examples 2 to 7, it can be seen that the addition amount of block regenerated nitrile rubber is too high (Comparative Example 2), the addition amount of powdered regenerated nitrile rubber is too high (Comparative Example 3), no powdered regenerated nitrile rubber is added (Comparative Example 4), no block regenerated nitrile rubber is added (Comparative Example 5), no liquid nitrile rubber is added (Comparative Example 6), and no chlorosulfonated polyethylene rubber is added (Comparative Example 7) will all lead to the mechanical properties of the obtained rubber composition for sealing rings to deteriorate and the compression permanent deformation to increase.

[0092] Finally, by comparing Example 2 and Comparative Example 8, it can be seen that if no anti-aging system is added, the aging resistance of the obtained rubber composition for sealing ring will be poor.

[0093] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate a rubber composition for a sealing ring containing recycled materials and its application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A rubber composition for sealing ring containing recycled materials, characterized in that: The rubber composition for sealing ring comprises the following components in parts by weight:

2. The rubber composition for a seal ring according to claim 1, characterized in that: The Mooney viscosity of the solid nitrile rubber is 45 to 65; Preferably, the mass percentage of acrylonitrile in the solid nitrile rubber is 28-33%; Preferably, the Mooney viscosity of the block-shaped recycled nitrile rubber is 40 to 50; Preferably, the mass percentage of ash in the block-shaped recycled nitrile rubber is less than 10%; Preferably, the Mooney viscosity of the powdered regenerated nitrile rubber is 40 to 50; Preferably, the mass percentage of ash in the powdered recycled nitrile rubber is less than 10%; Preferably, the powdered recycled nitrile rubber has a D 50 The particle size is 100~250μm.

3. The rubber composition for a seal ring according to claim 1 or 2, characterized in that: The Mooney viscosity of the chlorosulfonated polyethylene rubber is 30 to 60; Preferably, the mass percentage of chlorine in the chlorosulfonated polyethylene rubber is 33-37%, and the mass percentage of sulfur is 0.8-1.2%; Preferably, the Mooney viscosity of the liquid nitrile rubber is 30 to 50; Preferably, the mass percentage of acrylonitrile in the liquid nitrile rubber is 30-34%; Preferably, the number average molecular weight of the liquid nitrile rubber is 1000-2000.

4. The rubber composition for a seal ring according to any one of claims 1 to 3, characterized in that: The anti-aging system includes antioxidant 4020 and antioxidant RD; Preferably, the vulcanization system comprises 0.8 to 1.6 parts by weight of sulfur, 0.6 to 1.2 parts by weight of a vulcanization accelerator TMTD, and 0.6 to 1.2 parts by weight of a vulcanization accelerator DM.

5. The rubber composition for a seal ring according to any one of claims 1 to 4, characterized in that: The rubber composition for sealing ring further comprises 0.5 to 2 parts by weight of internal mold release agent; Preferably, the internal mold release agent includes zinc stearate and calcium stearate; Preferably, the rubber composition for sealing ring further comprises 1 to 2 parts by weight of a deodorant; Preferably, the deodorant comprises hydroquinone and salicylic acid.

6. A film for sealing ring containing recycled materials, characterized in that: The rubber sheet for sealing ring is prepared by using the rubber composition for sealing ring as claimed in any one of claims 1 to 5.

7. The film for sealing ring according to claim 6, characterized in that: The thickness of the sealing ring film is 0.2-2 mm.

8. A method for preparing a film for a sealing ring containing recycled materials as claimed in claim 6 or 7, characterized in that: The preparation method comprises: mixing various materials in the rubber composition for sealing rings according to specific dosages, and performing mixing, open milling and vulcanization molding to obtain the rubber sheet for sealing rings containing recycled materials.

9. The preparation method according to claim 8, characterized in that: The temperature of the vulcanization molding is 170-190° C., and the time is 40-60 seconds.

10. Use of the sealing ring film containing recycled materials as claimed in claim 6 or 7 in loudspeakers.

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