A rubber compound, a method for producing the same, and a switching valve

Abstract

This invention relates to the field of thermal management system technology, and more particularly to a compound rubber, its preparation method, and a switching valve. The compound rubber is used to prepare sealing gaskets for valve components that flow coolant. The compound rubber is prepared from raw materials comprising the following components: 45.15wt%–54.25wt% EPDM rubber; 16.32wt%–23.79wt% carbon black; 17.86wt%–25.05wt% paraffin oil; 2.11wt%–4.66wt% zinc oxide; 0.85wt%–1.72wt% stearic acid; 2.25wt%–4.75wt% tackifying resin; 2.5wt%–4.66wt% antioxidant; and 5.09wt%–7.36wt% peroxide vulcanizing agent. The compound rubber provided by this invention exhibits superior resistance to compressive stress.

Description

Technical Field

[0001] This invention relates to the field of thermal management system technology, and in particular to a compound rubber, its preparation method and switching valve. Background Technology

[0002] In energy storage devices, thermal management systems are used to ensure the proper functioning of battery cells and control components. Similarly, in new energy vehicles, motor cooling, battery heating / cooling, and passenger cabin temperature control all require thermal management systems. In thermal management systems, the flow path switching of coolant is generally achieved through flow path switching valves, and the coolant is generally a mixture of water and ethylene glycol.

[0003] A seal is installed between the valve core and the valve body of the flow path switching valve. The seal is generally made of rubber. The pressure resistance and performance of the rubber in the coolant directly affect the life of the seal. How to improve the pressure resistance and coolant resistance of the seal is a technical problem that needs to be solved. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a compound rubber, its preparation method and switching valve, wherein the seal made by the compound rubber provided by the present invention has good pressure resistance and coolant resistance.

[0005] This invention provides a compound rubber for use in preparing sealing gaskets for valve components that flow with coolant. The compound rubber is prepared from raw materials comprising the following components:

[0006]

[0007] Preferably, the EPDM rubber is EPDM rubber 3960Q.

[0008] Preferably, the carbon black is a high-abrasion-resistant carbon black.

[0009] Preferably, the tackifying resin is Koresin.

[0010] Preferably, the antioxidant is antioxidant 4010NA and antioxidant MB in a mass ratio of 1-2.5:1-2.5.

[0011] Preferably, the peroxide vulcanizing agent is peroxide vulcanizing agent DBPH-50.

[0012] The present invention also provides a method for preparing the above-described compound rubber, comprising the following steps:

[0013] S1) After mixing EPDM rubber in a mixer, add zinc oxide, stearic acid, tackifying resin and antioxidant and mix; then add carbon black and paraffin oil and mix; then perform plug lifting and rubber discharge to obtain masterbatch.

[0014] S2) The masterbatch is wrapped on the rollers of the open mill, a peroxide vulcanizing agent is added, the mill is turned over and rolled, and finally sheeted out to obtain the compound rubber.

[0015] Preferably, in step S1), the mixing time for adding EPDM rubber is 0.8 to 1.2 minutes;

[0016] The mixing time for adding zinc oxide, stearic acid, tackifying resin and antioxidant is 25-35 seconds;

[0017] The mixing time for adding carbon black and paraffin oil is 4.5 to 5.5 minutes.

[0018] The present invention also provides a switching valve having a valve cavity in which coolant can flow; the switching valve includes a sealing gasket, a valve core, and a valve housing, at least a portion of the sealing gasket being located between the valve core and the valve housing, the valve core being slidable relative to the sealing gasket, the sealing gasket including rubber and a wear-resistant diaphragm, the rubber being obtained by vulcanization of the aforementioned compound rubber, the wear-resistant diaphragm being attached to the valve core, and the rubber being attached to the inner wall of the valve housing.

[0019] Preferably, the material of the wear-resistant diaphragm is polytetrafluoroethylene;

[0020] The method for preparing the sealing gasket includes the following steps:

[0021] A) Sodium-modify the wear-resistant diaphragm;

[0022] B) Coat the sodium-treated membrane with a primer solution, and after curing, obtain a primer pre-layer;

[0023] C) Apply the topcoat solution onto the base coat pre-coated layer, and after curing, the topcoat pre-coated layer is obtained;

[0024] D) Place the composite material obtained in step C) into a vulcanization mold, inject raw rubber into the surface rubber preform layer of the composite material, and after a period of vulcanization, form a rubber elastic preform on the surface rubber preform layer; the raw rubber is the compound rubber described above.

[0025] E) After cutting, a two-stage vulcanization process is carried out to obtain the sealing gasket.

[0026] This invention provides a compound rubber for use in preparing sealing gaskets for valve components that circulate coolant. The compound rubber is prepared from raw materials comprising the following components: 45.15 wt%–54.25 wt% EPDM rubber; 16.32 wt%–23.79 wt% carbon black; 17.86 wt%–25.05 wt% paraffin oil; 2.11 wt%–4.66 wt% zinc oxide; 0.85 wt%–1.72 wt% stearic acid; 2.25 wt%–4.75 wt% tackifying resin; 2.5 wt%–4.66 wt% antioxidant; and 5.09 wt%–7.36 wt% peroxide vulcanizing agent; the sum of the contents of all the above components is 100%. The compound rubber provided by this invention exhibits superior resistance to compressive stress. The compound provided by this invention is used to prepare sealing gaskets, specifically sealing gaskets in switching valves. Since the valve core and sealing gasket in a switching valve are in a dynamic seal, and dynamic seals have higher requirements for pressure-transformation performance, the compound provided by this invention is suitable for preparing sealing gaskets for switching valves. Attached Figure Description

[0027] Figure 1 A schematic diagram of the structure of the sealing gasket provided in an embodiment of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides a compound rubber for use in preparing sealing gaskets for valve components that flow with coolant. The compound rubber is prepared from raw materials comprising the following components:

[0030]

[0031] The sum of the contents of the above components is 100%.

[0032] In some embodiments of the present invention, the EPDM rubber is EPDM rubber 3960Q.

[0033] In some embodiments of the present invention, the carbon black is high abrasion-resistant carbon black.

[0034] In some embodiments of the present invention, the tackifying resin is Koresin.

[0035] In some embodiments of the present invention, the antioxidant is antioxidant 4010NA and antioxidant MB in a mass ratio of 1-2.5:1-2.5.

[0036] In some embodiments of the present invention, the peroxide sulfiding agent is peroxide sulfiding agent DBPH-50.

[0037] In this invention, the peroxide vulcanizing agent mainly affects the product's pressure resistance performance; if the amount is too small, the hardness is insufficient; if the amount is too large, the elasticity is insufficient.

[0038] The compound of this invention does not require the addition of sulfur to meet the performance requirements of the product.

[0039] The present invention also provides a method for preparing the above-described compound rubber, comprising the following steps:

[0040] S1) After mixing EPDM rubber in a mixer, add zinc oxide, stearic acid, tackifying resin and antioxidant and mix; then add carbon black and paraffin oil and mix; then perform plug lifting and rubber discharge to obtain masterbatch.

[0041] S2) The masterbatch is wrapped on the rollers of the open mill, a peroxide vulcanizing agent is added, the mill is turned over and rolled, and finally sheeted out to obtain the compound rubber.

[0042] Regarding step S1):

[0043] The mixing time for adding EPDM rubber is 0.8 to 1.2 minutes, for example, 1 minute.

[0044] The mixing time for adding zinc oxide, stearic acid, tackifying resin and antioxidant is 25-35 seconds, for example, 30 seconds.

[0045] The mixing time for adding carbon black and paraffin oil is 4.5 to 5.5 minutes, for example, 5 minutes.

[0046] Regarding step S2):

[0047] After adding the peroxide vulcanizing agent, wait until the peroxide vulcanizing agent is fully absorbed into the masterbatch before starting the re-mixing process.

[0048] The thin-pass test was performed 6 times.

[0049] The present invention also provides a switching valve having a valve cavity in which coolant can flow; the switching valve includes a sealing gasket, a valve core, and a valve housing, at least a portion of the sealing gasket being located between the valve core and the valve housing, the valve core being slidable relative to the sealing gasket, the sealing gasket including rubber and a wear-resistant diaphragm, the rubber being obtained by vulcanization of the aforementioned compound rubber, the wear-resistant diaphragm being attached to the valve core, and the rubber being attached to the inner wall of the valve housing.

[0050] In some embodiments of the present invention, the method for preparing the sealing gasket includes the following steps:

[0051] A) Sodium-modify the wear-resistant diaphragm;

[0052] B) Coat the sodium-treated membrane with a primer solution, and after curing, obtain a primer pre-layer;

[0053] C) Apply the topcoat solution onto the base coat pre-coated layer, and after curing, the topcoat pre-coated layer is obtained;

[0054] D) Place the composite material obtained in step C) into a vulcanization mold, inject raw rubber into the surface rubber preform layer of the composite material, and after a period of vulcanization, form a rubber elastic preform on the surface rubber preform layer; the raw rubber is the compound rubber described above.

[0055] E) After cutting, a two-stage vulcanization process is carried out to obtain the sealing gasket.

[0056] Regarding step A):

[0057] The wear-resistant diaphragm is sodium-treated.

[0058] In some embodiments of the present invention, the wear-resistant diaphragm is made of polytetrafluoroethylene (PTFE). The thickness of the wear-resistant diaphragm is 0.35–0.45 mm, for example, 0.4 mm.

[0059] In some embodiments of the present invention, prior to sodium treatment, the process further includes pre-treatment of the wear-resistant diaphragm. The pre-treatment steps include sequential cleaning, acid washing, and water washing. The cleaning can be performed using an ultrasonic cleaner to remove surface dirt and impurities. The acid washing can use a sulfuric acid solution or hydrochloric acid solution with a concentration of 0.2–0.7 mol / L, such as 0.5 mol / L, to remove the surface oxide layer and organic matter. The water washing uses deionized water to remove residual acidic solution and impurities.

[0060] In some embodiments of the present invention, the sodium-modification solution is obtained by mixing anhydrous ethanol, anhydrous acetone, and solid sodium hydroxide. The mass content of solid sodium hydroxide in the sodium-modification solution is 3% to 5%, for example, 4%. The present invention does not impose any special restrictions on the ratio of anhydrous ethanol to anhydrous acetone; specifically, the mass ratio of anhydrous ethanol to anhydrous acetone is 1:1.

[0061] In some embodiments of the present invention, the sodium treatment method includes immersing the pretreated wear-resistant film in a sodium treatment solution. The immersion temperature can be 5–50°C, for example, 25°C; the immersion time can be 15–60 seconds, for example, 30 seconds. After sodium treatment, the method further includes washing with water and drying. The water washing uses deionized water to remove residual sodium treatment solution and impurities.

[0062] The sodium-treated abrasion-resistant diaphragm has a dyne value of 46 mN / m. Specifically, the abrasion-resistant diaphragm was tested using a No. 46 dyne pen, and the pattern was continuous.

[0063] Regarding step B):

[0064] A primer solution is coated onto a sodium-modified membrane, and after curing, a primer prepreg is obtained.

[0065] The surface tension of the wear-resistant diaphragm is reduced after sodium treatment, which helps with the subsequent application of the primer and improves the adhesion between the wear-resistant diaphragm and the primer.

[0066] Specifically, a primer solution is coated on one side of the sodium-modified membrane, and after curing, a primer pre-layer is obtained.

[0067] In some embodiments of the present invention, the primer solution comprises a primer adhesive and a primer solvent. The primer adhesive is selected from at least one of ThinkBond11H, ThinkBond11HS, and ThinkBond10. The primer solvent is selected from methyl isobutyl ketone (MIBK). The mass ratio of the primer adhesive to the primer solvent is 1 to 5:1; for example, 1.5:1, 2:1, 3:1, 4:1, or 5:1. Excessive use of the primer solvent will affect the bonding strength; insufficient use of the primer solvent will lead to waste and uneven application.

[0068] In some embodiments of the present invention, the environmental parameters for coating the primer solution include: a temperature of 0 to 30°C, such as 25°C; and a humidity of 30% to 80%, such as 50%.

[0069] In some embodiments of the present invention, the thickness of the base adhesive prepreg layer is 0.003 to 0.015 mm, for example, 0.008 mm.

[0070] Regarding step C):

[0071] A topcoat solution is applied to the base coat and cured to obtain the topcoat pre-coat layer.

[0072] In some embodiments of the present invention, the topcoat solution comprises a topcoat adhesive and a topcoat solvent. The topcoat adhesive is selected from at least one of ThinkBond27M, ThinkBond27MS, and ThinkBond26MS; and is sourced from Shanghai Lerui Curing Technology Co., Ltd. The topcoat solvent is selected from xylene. The mass ratio of the topcoat adhesive to the topcoat solvent is 3.5–4.5:0.3–2, for example, 4:0.7, 4:1, 4:1.5, or 4:2. Excessive use of the topcoat solvent will affect the bonding strength; insufficient use of the topcoat solvent will lead to waste and uneven application.

[0073] In some embodiments of the present invention, the environmental parameters for coating the adhesive solution include: a temperature of 0 to 30°C, such as 25°C; and a humidity of 30% to 80%, such as 50%.

[0074] In some embodiments of the present invention, the thickness of the pre-adhesive layer is 0.007 to 0.02 mm, for example, 0.01 mm.

[0075] Regarding step D):

[0076] The composite material obtained in step C) is placed in a vulcanization mold. Raw rubber is injected into the surface rubber preform layer of the composite material, and after a period of vulcanization, a rubber elastic preform is formed on the surface rubber preform layer.

[0077] In some embodiments of the present invention, the raw rubber is the compound rubber described above.

[0078] In some embodiments of the present invention, the temperature of the first vulcanization is 180-200°C, for example 190°C; and the time is 200-240s, for example 220s.

[0079] In some embodiments of the present invention, the thickness of the rubber elastic preform is 4.6 to 4.8 mm, for example, 4.7 mm.

[0080] Regarding step E):

[0081] After cutting, a two-stage vulcanization process is carried out to obtain the sealing gasket.

[0082] In some embodiments of the present invention, the cutting includes:

[0083] The material reserved for the window is cut off by stamping.

[0084] The cutting die includes a punch and a cutter that matches the punch; the punch is an arc-shaped die that matches the curvature of the composite material layer obtained in step D. During punching, the rubber elastic body of the product faces downward (towards the punch), and the wear-resistant diaphragm faces upward. On the one hand, the rubber elastic body has a positioning structure on one side for easy positioning; on the other hand, punching downward from the wear-resistant diaphragm is less likely to cause damage to the wear-resistant diaphragm.

[0085] In some embodiments of the present invention, the temperature of the two-stage vulcanization is 140-160°C, for example 150°C; and the time is 3-5 hours, for example 4 hours.

[0086] In some embodiments of the present invention, the sealing gasket is obtained by vulcanization of a composite layer material;

[0087] The composite layer material includes:

[0088] Abrasion-resistant diaphragm;

[0089] A pre-adhesive base layer is formed on the upper surface of the wear-resistant diaphragm;

[0090] A topcoat prepreg layer formed on the upper surface of the base adhesive prepreg layer;

[0091] A rubber elastic preform formed on the upper surface of the adhesive preform layer.

[0092] The pre-coated base layer is obtained by curing the base solution; the base solution is the same as described above and will not be repeated here.

[0093] The pre-coated adhesive layer is obtained by curing the adhesive solution; the adhesive solution is the same as described above and will not be repeated here.

[0094] The raw materials for preparing the rubber elastic preform are the same as those described above, and will not be repeated here.

[0095] In some embodiments of the present invention, the vulcanization is the two-stage vulcanization described above, with a temperature of 140-160°C, for example 150°C, and a time of 3-5 hours, for example 4 hours.

[0096] After vulcanization, the resulting gasket includes:

[0097] Wear-resistant layer;

[0098] An undercoat layer formed on the upper surface of the wear-resistant layer;

[0099] A topcoat layer formed on the upper surface of the base adhesive layer;

[0100] A rubber elastic body formed on the upper surface of the adhesive layer.

[0101] The structure of the sealing gasket is as follows: Figure 1 As shown. Figure 1 This is a schematic diagram of the sealing gasket provided in an embodiment of the present invention. S-1 is the wear-resistant layer, S-2 is the base adhesive layer, S-3 is the top adhesive layer, S-4 is the rubber elastic body, S-5 is the flow hole, and S-6 is the sealing rib.

[0102] The rubber elastic body S-4 has an arc-shaped cross-section. The inner surface of the rubber elastic body S-4 is sequentially provided with a top adhesive layer S-3, a bottom adhesive layer S-2, and a wear-resistant layer S-1. The outer surface of the rubber elastic body S-4 is provided with multiple sealing ribs S-6 arranged in a crisscross pattern.

[0103] The sealing gasket has multiple through-holes S-5 spaced apart. The through-holes S-5 have a rectangular structure and their positions cannot be shifted, so as to facilitate the flow of coolant.

[0104] In use, the sealing gasket is installed between the valve body and the valve core. The rubber elastic body S-4 is located on the side facing the valve body, and the wear-resistant layer S-1 is on the side facing the valve core. When the valve core is assembled, the valve body sealing gasket is squeezed. Multiple crisscrossing sealing ribs S-6 distributed on the rubber elastic body S-4 form a seal around the flow hole S-5, ensuring a leak-free seal. The inner wear-resistant layer S-1 is wear-resistant and has a low coefficient of friction, which reduces the valve core rotation resistance and produces no noise during rotation.

[0105] To further illustrate the present invention, the following detailed description of a compound rubber, its preparation method, and a switching valve provided by the present invention is provided in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0106] Example 1 of compound rubber synthesis

[0107] The raw materials for preparing the compound (i.e., the raw materials for preparing the rubber elastic matrix) include:

[0108]

[0109] The preparation method of the compound rubber includes the following steps:

[0110] 1) Internal mixing: Add EPDM rubber 3960Q to the internal mixer and mix for 1 min; then add zinc oxide, stearic acid, tackifying resin Koresin, antioxidant 4010NA and antioxidant MB and mix for 30 s; then add carbon black and paraffin oil and mix for 5 min; then perform plug lifting and rubber discharge to obtain masterbatch.

[0111] 2) Vulcanization: The masterbatch is wrapped on the rollers of the open mill, and peroxide vulcanizing agent DBPH-50 is added. After all the peroxide vulcanizing agent DBPH-50 is absorbed into the masterbatch, the mill is turned over and passed through 6 times. Finally, the mixture is sheeted out to obtain the compound.

[0112] Example 2 of compound rubber synthesis

[0113] The difference from Example 1 of compound rubber synthesis is as follows:

[0114] The raw materials for preparing the compound (i.e., the raw materials for preparing the rubber elastic matrix) include:

[0115]

[0116] Example 3 of compound rubber synthesis

[0117] The difference from Example 1 of compound rubber synthesis is as follows:

[0118] The raw materials for preparing the compound (i.e., the raw materials for preparing the rubber elastic matrix) include:

[0119]

[0120] Comparative Synthesis Example 1

[0121] The difference from Example 1 of compound rubber synthesis is as follows:

[0122] Replace the peroxide vulcanizing agent DBPH-50 with sulfur vulcanizing agent.

[0123] Comparative Synthesis Example 2

[0124] The difference from Example 1 of compound rubber synthesis is as follows:

[0125] Replace the peroxide vulcanizing agent DBPH-50 with the vulcanizing agent dicumyl peroxide DCP.

[0126] The performance of the compound rubbers obtained from Synthetic Examples 1-3 and Comparative Synthetic Examples 1-2 was tested, and the results are shown in Table 1.

[0127] Table 1. Performance test results of the compound obtained from Synthetic Examples 1-3 and Comparative Synthetic Examples 1-2.

[0128]

[0129]

[0130] As shown in Table 1, the rubber compound prepared in the embodiments of the present invention exhibits a compression set of less than 16% under conditions of 120℃×168h and 25% compression. In contrast, the rubber compound obtained by replacing the peroxide vulcanizing agent in the comparative embodiment shows a compression set significantly greater than 17% under the same conditions. Therefore, the rubber compound obtained by the present invention demonstrates significantly superior resistance to compression set. Furthermore, the rubber compound prepared in the embodiments of the present invention exhibits tensile strength variations between -20% and +20% and elongation at break variations between -30% and +30% under conditions of 120℃×168h and coolant (water:ethylene glycol = 1:1). In contrast, the rubber compound obtained by replacing the peroxide vulcanizing agent in the comparative embodiment shows tensile strength and elongation at break variations significantly exceeding these ranges. Therefore, the rubber compound prepared by the present invention exhibits superior resistance to compression set and coolant resistance.

[0131] In the examples and comparative examples, the raw rubber is the compound rubber of Synthetic Example 1.

[0132] Example 1

[0133] Preparation of sealing gaskets:

[0134] 1) Pre-treat the wear-resistant diaphragm (PTFE, 0.4mm thickness):

[0135] The equipment was cleaned using an ultrasonic cleaner, then acid-washed with a sulfuric acid solution (0.5 mol / L), and finally rinsed with deionized water.

[0136] Then sodiumization is performed:

[0137] The pretreated wear-resistant diaphragm was immersed in a sodium-based solution at a temperature of 25°C for 30 seconds. The sodium-based solution was prepared by mixing anhydrous ethanol, anhydrous acetone, and solid sodium hydroxide. The sodium hydroxide content in the sodium-based solution was 4% by mass, and the mass ratio of anhydrous ethanol to anhydrous acetone was 1:1.

[0138] After sodium treatment, the mixture is washed with deionized water.

[0139] The dyne value of the sodium-treated wear-resistant diaphragm is 46 mN / m.

[0140] 2) Coat the sodium-treated membrane with a primer solution, and after curing, obtain a primer pre-layer;

[0141] The primer solution comprises a primer adhesive and a primer solvent; the primer adhesive is ThinkBond11H, sourced from Shanghai Lerui Curing Technology Co., Ltd.; the primer solvent is methyl isobutyl ketone (MIBK). The mass ratio of the primer adhesive to the primer solvent is 4:1.

[0142] The environmental parameters for applying the primer solution include: temperature 25℃ and humidity 50%.

[0143] The thickness of the pre-adhesive base layer is 0.008 mm.

[0144] 3) Apply the topcoat solution onto the base coat pre-coated layer, and after curing, the topcoat pre-coated layer is obtained;

[0145] The topcoat solution comprises a topcoat adhesive and a topcoat solvent; the topcoat adhesive is selected from ThinkBond27M and is sourced from Shanghai Lerui Curing Technology Co., Ltd.; the topcoat solvent is selected from xylene. The mass ratio of the topcoat adhesive to the topcoat solvent is 4:0.7.

[0146] The environmental parameters for applying the adhesive solution include: temperature 25℃ and humidity 50%.

[0147] The thickness of the pre-coated adhesive layer is 0.01 mm.

[0148] 4) Place the composite material obtained in step 3) into a vulcanization mold, inject raw rubber into the surface rubber preform layer of the composite material, and vulcanize at 190°C for 220 seconds to form a rubber elastic preform (thickness of 4.7 mm) on the surface rubber preform layer.

[0149] 5) Cutting: The material reserved in the window is cut off by stamping. The cutting die includes a punch and a cutter that matches the punch. The punch is an arc-shaped die that matches the curvature of the composite material layer obtained in step 4. During punching, the rubber elastic preform side of the product faces down (towards the punch), and the wear-resistant diaphragm side faces up.

[0150] After cutting, the sealing gasket is obtained by two-stage vulcanization at 150℃ for 4 hours.

[0151] Example 2

[0152] The difference from Example 1 is as follows:

[0153] In step 2), the mass ratio of the primer adhesive to the primer solvent is 5:1. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0154] Example 3

[0155] The difference from Example 1 is as follows:

[0156] In step 2), the mass ratio of the primer adhesive to the primer solvent is 3:1. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0157] Example 4

[0158] The difference from Example 1 is as follows:

[0159] In step 2), the mass ratio of the primer adhesive to the primer solvent is 2:1. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0160] Example 5

[0161] The difference from Example 1 is as follows:

[0162] In step 2), the mass ratio of the primer adhesive to the primer solvent is 1.5:1. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0163] Example 6

[0164] The difference from Example 1 is as follows:

[0165] In step 3), the mass ratio of the topcoat adhesive to the topcoat solvent is 4:1. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0166] Example 7

[0167] The difference from Example 1 is as follows:

[0168] In step 3), the mass ratio of the topcoat adhesive to the topcoat solvent is 4:1.5. The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0169] Example 8

[0170] The difference from Example 1 is as follows:

[0171] In step 3), the mass ratio of the topcoat adhesive to the topcoat solvent is 4:2.

[0172] The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0173] Example 9

[0174] The difference from Example 1 is as follows:

[0175] In step 2), the primer adhesive is ThinkBond11HS, which comes from Shanghai Lerui Curing Technology Co., Ltd.

[0176] The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0177] Example 10

[0178] The difference from Example 1 is as follows:

[0179] In step 2), the primer adhesive is ThinkBond10, which comes from Shanghai Lerui Curing Technology Co., Ltd.

[0180] The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0181] Example 11

[0182] The difference from Example 1 is as follows:

[0183] In step 3), the topcoat adhesive is ThinkBond27MS, which comes from Shanghai Lerui Curing Technology Co., Ltd.

[0184] The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0185] Example 12

[0186] The difference from Example 1 is as follows:

[0187] In step 3), the topcoat adhesive is ThinkBond26MS, which comes from Shanghai Lerui Curing Technology Co., Ltd.

[0188] The remaining steps and parameters are the same as in Example 1, and a sealing gasket is obtained.

[0189] Sealing gaskets were prepared according to the methods of Examples 1-12, with five samples prepared for each example and comparative example. The peel force of the sealing gaskets was tested using a CL-5000N universal testing machine (Changlong Testing Machinery Factory, Jiangdu District). The average value of the five samples was recorded in Table 2.

[0190] Table 2. Average performance test results of the sealing gaskets prepared in Examples 1-12 and Comparative Examples 1-3.

[0191]

[0192] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A compound rubber for use in preparing sealing gaskets for valve components that allow the flow of coolant, said compound rubber being prepared from raw materials comprising the following components:

2. The compound according to claim 1, characterized in that, The EPDM rubber is EPDM 3960Q.

3. The compound according to claim 1, characterized in that, The carbon black is a high abrasion-resistant carbon black.

4. The compound according to claim 1, characterized in that, The tackifying resin is Koresin.

5. The compound according to claim 1, characterized in that, The antioxidant is antioxidant 4010NA and antioxidant MB, with a mass ratio of 1-2.5:1-2.

5.

6. The compound according to claim 1, characterized in that, The peroxide vulcanizing agent is peroxide vulcanizing agent DBPH-50.

7. A method for preparing the compound rubber according to any one of claims 1 to 6, comprising the following steps: S1) After mixing EPDM rubber in a mixer, add zinc oxide, stearic acid, tackifying resin and antioxidant and mix; then add carbon black and paraffin oil and mix; then perform plug lifting and rubber discharge to obtain masterbatch. S2) The masterbatch is wrapped on the rollers of the open mill, a peroxide vulcanizing agent is added, the mill is turned over and rolled, and finally sheeted out to obtain the compound rubber.

8. The preparation method according to claim 7, characterized in that, In step S1), the mixing time for adding EPDM rubber is 0.8–1.2 min; The mixing time for adding zinc oxide, stearic acid, tackifying resin and antioxidant is 25-35 seconds; The mixing time for adding carbon black and paraffin oil is 4.5 to 5.5 minutes.

9. A switching valve having a valve chamber through which coolant can flow; the switching valve comprising a gasket, a valve core, and a valve housing, wherein at least a portion of the gasket is located between the valve core and the valve housing, the valve core being slidable relative to the gasket, the gasket comprising rubber and a wear-resistant diaphragm, the rubber being obtained by vulcanization of the compound rubber according to any one of claims 1 to 6, the wear-resistant diaphragm being attached to the valve core, and the rubber being attached to the inner wall of the valve housing.

10. The switching valve according to claim 9, characterized in that, The wear-resistant diaphragm is made of polytetrafluoroethylene; The method for preparing the sealing gasket includes the following steps: A) Sodium-modify the wear-resistant diaphragm; B) Coat the sodium-treated membrane with a primer solution, and after curing, obtain a primer pre-layer; C) Apply the topcoat solution onto the base coat pre-coated layer, and after curing, the topcoat pre-coated layer is obtained; D) Place the composite material obtained in step C) into a vulcanization mold, inject raw rubber into the surface rubber preform layer of the composite material, and vulcanize it to form a rubber elastic preform on the surface rubber preform layer; the raw rubber is the compound rubber according to any one of claims 1 to 6. E) After cutting, a two-stage vulcanization process is carried out to obtain the sealing gasket.

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