EPDM rubber material and preparation method and application thereof

Abstract

The invention provides an EPDM (Ethylene-Propylene-Diene Monomer) rubber material and a preparation method and application thereof, and relates to the technical field of rubber materials. The EPDM rubber material is prepared from the following raw materials in parts by mass: 100 to 200 parts of raw EPDM rubber, 50 to 80 parts of composite modified white carbon black, 8 to 15 parts of a plasticizer, 0.5 to 2.0 parts of an anti-aging agent, 1.0 to 3.0 parts of a dispersing agent, 3.0 to 7.0 parts of a vulcanizing agent and 0.5 to 3.0 parts of an assistant cross-linking agent. The EPDM rubber material provided by the invention has good compatibility in a mixed solution of a refrigerant and refrigerating machine oil, has excellent mechanical properties, and can be applied to EPDM rubber products of an automobile air conditioning refrigeration system.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, and in particular to an EPDM rubber material and a preparation method and application thereof. Background Art

[0002] The rapid development of the new energy automobile industry has put forward higher requirements for automobile air conditioning and refrigeration systems. As a part of the automobile thermal management system, the automobile air conditioning system not only affects the riding comfort, but also the vehicle safety. If the automobile air conditioning compressor is called the "heart" of the automobile refrigeration system, then the refrigerant is like the "blood", which has an important impact on the operation and performance of the refrigeration system.

[0003] The development of automobile air conditioning refrigerants has gone through four generations. At present, the third-generation refrigerant R134a is mainly used in China. Its global warming potential value is 1300, which does not meet the legal and regulatory requirements issued by the European Union and the US Environmental Protection Agency. European and American countries have gradually banned it, and the new environmentally friendly refrigerant R1234yf has replaced R134a and become the international mainstream. The refrigeration oils PAG and POE that match environmentally friendly refrigerants are alcohol lubricants and polyester lubricants, respectively, with different polarities. The existing EPDM rubber materials are not compatible with both types of refrigeration oils at the same time. Therefore, it is urgent to make a technological breakthrough and develop EPDM rubber materials that meet the requirements of environmentally friendly refrigerants and mixed media of refrigeration oils of different polarities. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes an EPDM rubber material and a preparation method and application thereof.

[0005] The EPDM rubber material provided by the present invention comprises the following raw materials in parts by weight: 100-200 parts of ethylene propylene diene monomer raw rubber, 50-80 parts of composite modified white carbon black, 8-15 parts of plasticizer, 0.5-2.0 parts of antioxidant, 1.0-3.0 parts of dispersant, 3.0-7.0 parts of vulcanizer and 0.5-3.0 parts of cross-linking aid.

[0006] Preferably, the EPDM raw rubber has a Mooney viscosity ML (1+4) of 60 to 90 at 125°C, and the third monomer type is ethylidene norbornene, dicyclopentadiene or 1,4-hexadiene, and the content is 4.5 to 8.5.

[0007] Preferably, the preparation method of the composite modified silica comprises:

[0008] S1. Preparation of hydroxylated modified graphene: graphene, iron salt and water are mixed evenly, and the pH is adjusted to obtain a graphene solution, a hydrogen peroxide solution is added to the graphene solution and mixed evenly to obtain a hydroxylated modified graphene solution, and the hydroxylated modified graphene solution is filtered and vacuum dried to obtain hydroxylated modified graphene;

[0009] S2. Preparation of silane coupling agent modified white carbon black: mixing a silane coupling agent, water and ethanol evenly to obtain a silane coupling agent solution, adding white carbon black to the silane coupling agent solution and mixing evenly, washing, centrifuging and vacuum drying to obtain silane coupling agent modified white carbon black;

[0010] S3. Mix the hydroxylated modified graphene, the silane coupling agent modified white carbon black and water, disperse them evenly, centrifuge, dry and grind them to obtain composite modified white carbon black.

[0011] More preferably, in the S1, the mass ratio of graphene, iron salt and water is 1:(10-20):(100-200).

[0012] More preferably, in said S1, the iron salt is selected from one or more of ferric chloride, ferrous chloride, ferrous sulfate and ferric nitrate.

[0013] More preferably, in said S1, the pH is adjusted to 3-6.

[0014] More preferably, in said S1, the mass fraction of hydrogen peroxide in the hydrogen peroxide solution is 4-8wt%.

[0015] More preferably, in the S1, the mass ratio of the graphene solution to the hydrogen peroxide solution is 1:(1.2-1.8).

[0016] More preferably, in S2, the silane coupling agent is selected from one or more of KH-550, KH-560, and KH-570.

[0017] More preferably, in the S2, the mass ratio of the silane coupling agent, water and ethanol is (1-2):1:(10-20).

[0018] More preferably, in the S2, the mass ratio of white carbon black to silane coupling agent is 20:(1-5).

[0019] More preferably, in the S3, the mass ratio of hydroxylated modified graphene, silane coupling agent modified white carbon black and water is (25-35): (10-25): 50.

[0020] Preferably, the plasticizer is selected from one or more of paraffin oil, aromatic oil and coumarone.

[0021] Preferably, the antioxidant is selected from one or more of 2-thiolmethylbenzimidazole and 2,2,4-trimethyl-1,2-dihydroquinoline polymer.

[0022] Preferably, the dispersant is selected from one or more of dispersant FL and dispersant PEG 4000.

[0023] Preferably, the vulcanizing agent is selected from one or more of dicumyl peroxide, 2,5-dimethyl-2,5-dihexane, and vulcanizing agent 101XL45-SP2.

[0024] Preferably, the auxiliary cross-linking agent is selected from one or more of triallyl isocyanurate and trimethylolpropane trimethacrylate.

[0025] The present invention also provides a method for preparing an EPDM rubber material, comprising the following steps:

[0026] S1. Weigh the raw materials according to their mass parts, add them into an internal mixer for thorough mixing, and filter to obtain a mixed rubber material;

[0027] S2, heat-refining the mixed rubber material evenly through an open mill, extruding and molding to obtain a rubber sheet, and subjecting the rubber sheet to a primary vulcanization treatment;

[0028] S3, subjecting the rubber sheet after the primary vulcanization treatment to a secondary vulcanization treatment, to obtain.

[0029] Preferably, in S2, the conditions for the primary vulcanization treatment are: a vulcanization temperature of 165-180°C, a vulcanization time of 300-600s, and a vulcanization pressure of 140-180Kgf / cm 2 .

[0030] Preferably, in S3, the conditions for the secondary vulcanization treatment are: the vulcanization temperature is 160-180° C., and the vulcanization time is 0.5-4 h.

[0031] Application of the above EPDM rubber material or the EPDM rubber material prepared by the above preparation method in automobile air-conditioning refrigeration system.

[0032] The beneficial effects of the present invention are:

[0033] The EPDM rubber material provided by the present invention comprises ethylene propylene diene monomer rubber raw rubber, composite modified white carbon black, plasticizer, antioxidant, dispersant, vulcanizing agent, and cross-linking agent. The raw materials work synergistically, and the prepared EPDM rubber material has excellent mechanical properties and tolerance. In the present invention, composite modified white carbon black is used as a reinforcing material, and white carbon black is modified by a silane coupling agent, so that a dehydration reaction occurs between the silanol group on the surface of the white carbon black and the alkoxy group of the silane coupling agent, thereby improving the surface hydrophobicity of the white carbon black, reducing the degree of agglomeration between the white carbon black, and enhancing the interface interaction with the rubber molecular chain; at the same time, during the vulcanization process, the hydrophobic group of the silane coupling agent will form a chemical bond with the active group of the rubber, so that the two are closely fitted; the graphene is modified by hydroxylation, so that it is connected to the white carbon black by a hydrogen bond, and the white carbon black and the rubber matrix are closely connected by the chemical bond between the silane coupling agents, so that the three are closely fitted together; and the closely stacked sheet structure between the graphene is used to prevent the refrigerant and refrigeration oil molecules from entering the rubber. Therefore, the EPDM rubber material prepared by the present invention has good tolerance to environmentally friendly refrigerants and refrigeration oils, can be well compatible with PAG and POE refrigeration oils of different polarities, and has broad application potential in the field of rubber technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention provides a schematic diagram of the process for preparing the composite modified silica.

[0035] Figure 2 The XPS spectra of graphene (a) and hydroxylated modified graphene (b) in Example 1 of the present invention.

[0036] Figure 3 IR spectra of white carbon black (a) and white carbon black modified with silane coupling agent (b) in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is described in detail through specific embodiments.

[0038] Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources.

[0039] Example 1

[0040] An EPDM rubber material includes the following raw materials in parts by mass: 100 parts of EPDM raw rubber, 60 parts of composite modified white carbon black, 8 parts of plasticizer, 0.5 parts of antioxidant, 1.2 parts of dispersant, 5.7 parts of vulcanizer, and 0.8 parts of cross-linking agent. The plasticizer used is paraffin oil Sunpar 2280, the antioxidant is 2-mercaptomethyl benzimidazole, the dispersant is FL, the vulcanizer is diisopropyl peroxide, and the cross-linking agent is triallyl isocyanurate.

[0041] The EPDM raw rubber has a Mooney viscosity ML (1+4) of 65 at 125°C, and the third monomer type is ethylidene norbornene, with a content of 4.8.

[0042] Wherein, the preparation method of composite modified white carbon black comprises:

[0043] S1. Preparation of hydroxylated modified graphene: Graphene, FeCl2·4H2O and water were mixed at a mass ratio of 1:10:120 at a speed of 500 r / min, the pH was adjusted to 3, and stirring was continued for 30 min to obtain a graphene solution, 7% hydrogen peroxide solution was slowly and uniformly added to the graphene solution and mixed to obtain a hydroxylated modified graphene solution, the hydroxylated modified graphene solution was washed and filtered with deionized water, and vacuum dried at 40°C for 2 h to obtain hydroxylated modified graphene; wherein the mass ratio of the graphene solution to the hydrogen peroxide solution was 1:1.5;

[0044] S2. Preparation of silane coupling agent modified white carbon black: KH-570 silane coupling agent, water and ethanol were mixed in a mass ratio of 1.6:1:15, stirred at 4000 r / min for 40 min at room temperature to cause hydrolysis reaction to obtain a silane coupling agent solution, white carbon black was added to the silane coupling agent solution, stirred at 4000 r / min for 2 h at 60°C, washed with ethanol 3 times, centrifuged at 5000 r / min for 10 min, and vacuum dried at 40°C for 5 h to obtain silane coupling agent modified white carbon black; wherein the mass ratio of white carbon black to silane coupling agent is 20:3;

[0045] S3. Mix the hydroxylated modified graphene, the silane coupling agent modified white carbon black and water in a mass ratio of 25:15:50, ultrasonically disperse for 30 minutes, centrifuge for 35 minutes, and dry and grind at 60°C to obtain a composite modified white carbon black.

[0046] A method for preparing an EPDM rubber material comprises the following steps:

[0047] S1. Weigh the raw materials according to their mass parts, add them into an internal mixer for thorough mixing, and filter to obtain a mixed rubber material;

[0048] S2. The mixed rubber material is heat-mixed evenly through an open mill, extruded to obtain a rubber sheet, and the rubber sheet is subjected to a vulcanization treatment: the vulcanization temperature is 175°C, the vulcanization time is 600s, and the vulcanization pressure is 170Kgf / cm 2 ;

[0049] S3, subjecting the rubber sheet after the primary vulcanization treatment to a secondary vulcanization treatment: the vulcanization temperature is 170° C., and the vulcanization time is 1 h.

[0050] Example 2

[0051] An EPDM rubber material comprises the following raw materials in parts by mass: 120 parts of ethylene propylene diene monomer raw rubber, 80 parts of composite modified white carbon black, 8 parts of plasticizer, 0.5 parts of antioxidant, 1.2 parts of dispersant, 5.2 parts of vulcanizer, and 1.0 parts of cross-linking agent; the plasticizer used is paraffin oil Plaxene 1100, the antioxidant is 2-thiol methylbenzimidazole, the dispersant is PEG 4000, the vulcanizer is 2,5-dimethyl-2,5-dihexane, and the cross-linking agent is trimethylolpropane trimethacrylate.

[0052] The EPDM raw rubber has a Mooney viscosity ML (1+4) of 80 at 125°C, and the third monomer type is ethylidene norbornene, with a content of 4.2.

[0053] Wherein, the preparation method of composite modified white carbon black comprises:

[0054] S1. Preparation of hydroxylated modified graphene: Graphene, FeCl2·4H2O and water were mixed at a mass ratio of 1:10:120 at a speed of 500 r / min, the pH was adjusted to 3.5, and stirring was continued for 30 min to obtain a graphene solution, 7% hydrogen peroxide solution was added to the graphene solution and mixed to obtain a hydroxylated modified graphene solution, the hydroxylated modified graphene solution was washed and filtered with deionized water, and vacuum dried at 40° C. for 2 h to obtain hydroxylated modified graphene; wherein the mass ratio of the graphene solution to the hydrogen peroxide solution was 1:1.8;

[0055] S2. Preparation of silane coupling agent modified white carbon black: KH-570 silane coupling agent, water and ethanol were mixed in a mass ratio of 1.7:1:18, stirred at room temperature at 4000 r / min for 40 min to cause hydrolysis reaction to obtain a silane coupling agent solution, white carbon black was added to the silane coupling agent solution, stirred at 60°C at a speed of 4000 r / min for 2 h, washed with ethanol 3 times, centrifuged at 5000 r / min for 10 min, and vacuum dried at 40°C for 5 h to obtain silane coupling agent modified white carbon black; wherein the mass ratio of white carbon black to silane coupling agent is 20:4;

[0056] S3. Mix the hydroxylated modified graphene, the silane coupling agent modified white carbon black and water in a mass ratio of 30:20:50, mechanically disperse for 40 minutes, centrifuge for 40 minutes, and dry and grind at 60° C. to obtain a composite modified white carbon black.

[0057] A method for preparing an EPDM rubber material comprises the following steps:

[0058] S1. Weigh the raw materials according to their mass parts, add them into an internal mixer for thorough mixing, and filter to obtain a mixed rubber material;

[0059] S2. The mixed rubber material is heat-mixed evenly through an open mill, extruded to obtain a rubber sheet, and the rubber sheet is subjected to a vulcanization treatment: the vulcanization temperature is 175°C, the vulcanization time is 600s, and the vulcanization pressure is 170Kgf / cm 2 ;

[0060] S3, subjecting the rubber sheet after the primary vulcanization treatment to a secondary vulcanization treatment: the vulcanization temperature is 170° C., and the vulcanization time is 1 h.

[0061] Comparative Example 1

[0062] The difference between Comparative Example 1 and Example 1 is that the composite modified silica in Example 1 is replaced by silica, and other conditions are the same as those in Example 1.

[0063] Comparative Example 2

[0064] The difference between Comparative Example 2 and Example 2 is that the composite modified silica in Example 2 is replaced by silica, and other conditions are the same as those in Example 2.

[0065] The EPDM rubber material obtained above was subjected to performance tests, and the test results are shown in Table 1.

[0066] Table 1

[0067]

[0068] It can be seen from the results in Table 1 that the materials of Examples 1 to 2 have better mechanical properties, compression permanent deformation properties, hot air aging properties, and tolerance to new refrigerants and refrigeration oils than the materials of Comparative Examples 1 to 2. After aging with refrigerants / refrigeration oils, the materials of Examples 1 to 2 can still maintain good mechanical properties. This is because the silane-modified white carbon black is not prone to clustering and can be better dispersed in the rubber matrix, thereby enhancing the mechanical properties of the rubber; secondly, the stacking of graphene sheets effectively blocks the refrigerant and refrigeration oil molecules from invading the interior of the rubber, thereby improving the solvent tolerance of the rubber. The white carbon black used in Comparative Examples 1-2 is ordinary precipitated white carbon black. Due to the presence of hydrophilic groups such as silanol groups on the surface of white carbon black, white carbon black is prone to clustering, resulting in poor dispersibility. In addition, the silanol groups will also adsorb part of the vulcanizing agent, resulting in a decrease in the degree of vulcanization crosslinking, thereby making the rubber mechanical properties worse than those of Examples 1-2. In addition, in the refrigerant / refrigeration oil tolerance test, due to the poor dispersibility of white carbon black, the refrigerant / refrigeration oil molecules invade the rubber material and enter between the rubber molecules, causing the rubber to swell, resulting in a significant decrease in its various mechanical properties, reducing the sealing performance of the EPDM material, and refrigerant leakage is very likely to occur under long-term use, seriously endangering the driving safety of the vehicle.

[0069] Figure 1 The present invention provides a schematic diagram of the process for preparing the composite modified silica. Figure 2 The XPS spectra of graphene (a) and hydroxylated modified graphene (b) in Example 1 of the present invention show that the peak intensity of the characteristic peak of O1s in the vicinity of 530 eV of the hydroxylated modified graphene increases, indicating that the carboxylation modification of graphene is successful. Figure 3 The infrared spectra of the white carbon black (a) and the white carbon black modified by the silane coupling agent (b) in Example 1 of the present invention are shown in FIG. The white carbon black modified by the silane coupling agent has an infrared spectroscopy of 1019.9 cm -1 and 801.1cm -1 A characteristic peak representing the Si-O bond appeared at , indicating that the silane coupling agent has been successfully grafted onto the surface of silica.

[0070] In summary, the EPDM rubber material provided by the present invention has good compatibility in the mixed liquid of refrigerant and refrigeration oil and excellent mechanical properties, and can be applied to EPDM rubber products of automobile air-conditioning refrigeration system.

[0071] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An EPDM rubber material, characterized in that: The invention comprises the following raw materials in parts by weight: 100-200 parts of EPDM raw rubber, 50-80 parts of composite modified white carbon black, 8-15 parts of plasticizer, 0.5-2.0 parts of antioxidant, 1.0-3.0 parts of dispersant, 3.0-7.0 parts of vulcanizer and 0.5-3.0 parts of cross-linking agent.

2. The EPDM rubber material according to claim 1, characterized in that: The EPDM raw rubber has a Mooney viscosity ML (1+4) of 60 to 90 at 125°C, and the third monomer type is ethylidene norbornene, dicyclopentadiene or 1,4-hexadiene, and the content is 4.5 to 8.

5.

3. The EPDM rubber material according to claim 1, characterized in that: The preparation method of the composite modified white carbon black comprises: S1. Preparation of hydroxylated modified graphene: graphene, iron salt and water are mixed evenly, and the pH is adjusted to obtain a graphene solution, a hydrogen peroxide solution is added to the graphene solution and mixed evenly to obtain a hydroxylated modified graphene solution, and the hydroxylated modified graphene solution is filtered and vacuum dried to obtain hydroxylated modified graphene; S2. Preparation of silane coupling agent modified white carbon black: mixing a silane coupling agent, water and ethanol evenly to obtain a silane coupling agent solution, adding white carbon black to the silane coupling agent solution and mixing evenly, washing, centrifuging and vacuum drying to obtain silane coupling agent modified white carbon black; S3. Mix the hydroxylated modified graphene, the silane coupling agent modified white carbon black and water, disperse them evenly, centrifuge, dry and grind them to obtain composite modified white carbon black.

4. The EPDM rubber material according to claim 3, characterized in that: In the S1, the mass ratio of graphene, iron salt and water is 1:(10-20):(100-200); in the S2, the silane coupling agent is selected from one or more of KH-550, KH-560 and KH-570.

5. The EPDM rubber material according to claim 1, characterized in that: The vulcanizing agent is selected from one or more of dicumyl peroxide, 2,5-dimethyl-2,5-dihexane, and vulcanizing agent 101XL45-SP2.

6. The EPDM rubber material according to claim 1, characterized in that: The auxiliary cross-linking agent is selected from one or more of triallyl isocyanurate and trimethylolpropane trimethacrylate.

7. A method for preparing the EPDM rubber material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Weigh the raw materials according to their mass parts, add them into an internal mixer for thorough mixing, and filter to obtain a mixed rubber material; S2, heat-refining the mixed rubber material evenly through an open mill, extruding and molding to obtain a rubber sheet, and subjecting the rubber sheet to a primary vulcanization treatment; S3, subjecting the rubber sheet after the primary vulcanization treatment to a secondary vulcanization treatment, to obtain.

8. The preparation method according to claim 7, characterized in that: In the above S2, the conditions of the primary vulcanization treatment are: the vulcanization temperature is 165-180°C, the vulcanization time is 300-600s, and the vulcanization pressure is 140-180Kgf / cm 2 .

9. The preparation method according to claim 7, characterized in that: In the above-mentioned S3, the conditions of the secondary vulcanization treatment are: the vulcanization temperature is 160-180° C., and the vulcanization time is 0.5-4 hours.

10. Use of the EPDM rubber material according to any one of claims 1 to 6 or the EPDM rubber material prepared by the preparation method according to any one of claims 7 to 9 in an automobile air conditioning refrigeration system.

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