A low-temperature resistant EPDM rubber material and its preparation method and application

Abstract

The present invention discloses a low-temperature resistant EPDM rubber material, its preparation method, and application. The above-mentioned low-temperature resistant EPDM rubber material includes the following raw materials: an EPDM rubber base material, a plasticizer, a reinforcing agent, and a vulcanizing agent; wherein, in the EPDM rubber base material, the mass content of ethylene monomer is 45% to 50%; the plasticizer is a polyether; the reinforcing agent is powdered carbon black with a DBP absorption value of 80 to 110 mL / 100 g; the vulcanizing agent includes peroxide and sulfur. By matching the raw materials, the low-temperature resistance of the material is significantly improved, and the comprehensive performance of the rubber material is excellent. The present invention also provides a preparation method and application of the above-mentioned low-temperature resistant EPDM rubber material.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber materials, and in particular to a low-temperature resistant EPDM rubber material, a preparation method thereof, and applications thereof. Background Art

[0002] EPDM is a terpolymer of ethylene, propylene, and a non-conjugated diene (the third monomer). The main chain of the molecule is composed entirely of chemically stable saturated hydrocarbons. The ethylene and propylene monomer units are randomly arranged along the main chain. Even though a small amount of unsaturated double bonds are introduced into the side chains of the molecule, the absence of polar substituents in the molecule results in low intermolecular cohesive energy, making the molecular chain flexible and able to maintain good resilience at room temperature. However, at low temperatures, the relaxation process of the molecular chain slows down dramatically, and the elasticity of the rubber material also decreases.

[0003] EPDM rubber products used in cable accessories need to work in low-temperature environments. However, EPDM rubber materials have poor low-temperature resilience. At low temperatures, the hardness, modulus and intramolecular friction of the rubber increase, resulting in a decrease in the working ability of the rubber products. Especially in the northern market, rubber cable accessories lose their elastic properties due to being in a low-temperature environment for a long time, resulting in gaps between the rubber parts and the connectors, resulting in operational failures such as breakdown.

[0004] Therefore, it is necessary to develop a low-temperature resistant EPDM rubber material. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a low-temperature resistant EPDM rubber material, which improves the low-temperature resistance of the material and ensures mechanical properties.

[0006] The present invention also provides a method for preparing the low-temperature resistant EPDM rubber material.

[0007] The present invention also proposes the application of the low-temperature resistant EPDM rubber material.

[0008] The first embodiment of the present invention relates to a low-temperature resistant EPDM rubber material, comprising the following preparation raw materials: an EPDM rubber base material, a plasticizer, a reinforcing agent, and a vulcanizing agent; wherein the mass content of ethylene monomer in the EPDM rubber base material is 45% to 50%; the plasticizer is a polyether; the reinforcing agent is powdered carbon black with a DBP absorption value of 80 to 110 mL / 100 g; and the vulcanizing agent includes peroxide and sulfur.

[0009] The low-temperature resistant EPDM rubber material according to the first embodiment of the present invention has at least the following beneficial effects:

[0010] The ethylene monomer content in the EPDM rubber base material is relatively low, which reduces the overall crystallization ability of the molecular chain while ensuring strength, reduces low-temperature hardening, and ensures better low-temperature elasticity.

[0011] Using low-reinforcement carbon black with a lower DBP absorption value reduces the intermolecular forces between the carbon black and the rubber substrate, providing reinforcement while better ensuring the mobility of the chain segments. Therefore, after filling with low-reinforcement carbon black, the rubber material will have a lower hardness, a lower modulus, weaker intermolecular forces, stronger mobility, and better low-temperature resistance.

[0012] The vulcanizing agent adopts a mixed vulcanization system of peroxide and sulfur, which has the following advantages: the CC cross-linking bond formed by the peroxide vulcanizer after vulcanization has a higher bond energy, making it more resistant to external forces and showing better resilience; the sulfur vulcanizer forms polysulfide bonds after the vulcanization reaction, and its longer molecular chain can increase the softness of the molecule; in addition, the regularity of the molecular chain is reduced after cross-linking, which reduces the crystallinity under low temperature conditions and improves the low temperature resistance of the material.

[0013] Polyether plasticizers have good compatibility with EPDM rubber substrates and can better ensure the mobility of molecular chains.

[0014] By using a low-ethylene EPDM rubber base, combined with a mixed vulcanization system of peroxide and sulfur, and filled with low-reinforcement carbon black and polyether plasticizers, the material achieves significant improvements in low-temperature resistance while maintaining mechanical properties. Results show that at -40°C, the following can be achieved: permanent deformation at 200% stretching is ≤30%; permanent deformation at 25% compression is ≤40%; the increase in modulus of tensile stress compared to room temperature is ≤50%; the decrease in elongation at break is ≤15% compared to room temperature; and the increase in hardness (Shore A) is ≤10 compared to room temperature. This significantly improves the material's low-temperature resistance and demonstrates excellent overall performance.

[0015] In some embodiments, the weight content of the third monomer in the EPDM rubber base material is 2% to 10%, for example, any value among 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value therebetween. Controlling the third monomer content within the above range can better balance strength and low-temperature resistance.

[0016] In some embodiments, the mass content of the third monomer in the EPDM rubber base material is 3% to 6%.

[0017] Non-limiting examples of the third monomer include vinyl norbornene (ENB) and dicyclopentadiene (DCPD). ENB is commonly used and offers a higher crosslinking rate. DCPD has a cyclic structure that remains cyclic after crosslinking with a vulcanizing agent, resulting in improved mechanical stability and better maintenance of the inherent three-dimensional structure between rubber molecules, thereby ensuring resilience.

[0018] In some embodiments, the Mooney viscosity of the EPDM rubber base material is 15 to 25 (ML1+4, 125°C), for example, the Mooney viscosity of ML1+4 / 125°C is any value among 15, 20, 25 or any value in between.

[0019] In some embodiments, the plasticizer has a number average molecular weight of 200 to 500 and a pour point of less than -60°C. A smaller molecular weight, lower viscosity, and a lower pour point provide excellent fluidity even at low temperatures, acting as a lubricant between macromolecules and further improving the mobility of the molecular chains.

[0020] In some embodiments, the mass of the plasticizer is 10% to 30% of the mass of the EPDM rubber base material, for example, it can be any value among 10%, 15%, 30% or any value in between.

[0021] In some embodiments, the DBP absorption value of the powdered carbon black is any one of 80 mL / 100 g, 90 mL / 100 g, 100 mL / 100 g, 110 mL / 100 g, or any value therebetween.

[0022] In some embodiments, the specific surface area of ​​the powdered carbon black is 60 to 100 m 2 / g, for example, it can be 60m 2 / g、70m 2 / g、80m 2 / g、90m 2 / g、100m 2 A smaller specific surface area can reduce the gaps between carbon black primary particles or secondary particles, making the packing more compact, reducing the impact on the mobility of the EPDM rubber molecular chain, and improving the activity of the molecular chain.

[0023] In some embodiments, the mass of the powdered carbon black is 40% to 70% of the mass of the EPDM rubber base material, for example, it can be any value among 40%, 50%, 60%, 70% or any value in between.

[0024] In some embodiments, the peroxide is selected from one or more of dicumyl peroxide and 2,5-dimethyl-2,5-di-tert-butylperoxyhexane.

[0025] In some embodiments, the sulfur is selected from insoluble sulfur.

[0026] In some embodiments, the mass of the peroxide in the vulcanizing agent is 3% to 6% of the mass of the EPDM rubber base material, and the mass of the sulfur is 0.2% to 0.8% of the mass of the EPDM rubber base material. For example, the mass of the peroxide is 3%, 4%, 5% or 6% of the mass of the EPDM rubber base material, or any value therebetween, and the mass of the sulfur is 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8% of the mass of the EPDM rubber base material, or any value therebetween.

[0027] By adjusting the composition of the vulcanization system and controlling the degree of crosslinking, as well as the ratio of sulfur and CC crosslinks in the rubber compound, the performance of the rubber compound can be further improved. Increasing the peroxide and sulfur content increases the crosslink density of the material. However, excessive crosslinking density can lead to a more stable spatial network structure, increased steric hindrance to molecular chain movement, and increased mechanical modulus, which can in turn reduce the material's resilience. Conversely, a low degree of crosslinking reduces the material's ability to resist external forces, affecting its resistance to permanent deformation. By controlling the ratio of peroxide and sulfur, the sulfur and CC crosslinks can be better utilized, resulting in greater compound stability and improved overall performance.

[0028] In some embodiments, the raw materials for preparing the low-temperature resistant EPDM rubber material also include a cross-linking agent, which can accelerate the vulcanization speed, improve the vulcanization efficiency, and shorten the process time.

[0029] In some embodiments, the auxiliary cross-linking agent is selected from one or more of triallyl isocyanurate and 2-mercaptobenzothiazole.

[0030] In some embodiments, the mass of the co-crosslinking agent is 1 / 5 to 1 / 3 of the mass of the peroxide in the vulcanizing agent, for example, specifically 1 / 5, 1 / 4 or 1 / 3, or any value in between. If the content of the co-crosslinking agent is too high, the vulcanization speed will be too fast, resulting in a shorter scorch time, and the controllable process time range during product production will be too short. For example, when the peroxide accounts for 3wt% to 6wt% of the EPDM rubber base, the proportion of the co-crosslinking agent relative to the EPDM rubber base can be 0.6wt% to 2wt%, and further can be 1wt% to 2wt%.

[0031] In some embodiments, the raw materials for preparing the low-temperature resistant EPDM rubber material further include an active agent.

[0032] In some embodiments, the active agent is selected from one or more of zinc oxide and stearic acid.

[0033] In some embodiments, the active agent is selected from a combination of zinc oxide and stearic acid, wherein the weight ratio of zinc oxide to stearic acid is, for example, 4 to 6:1, specifically 4:1, 5:1, or 6:1, or any value therebetween.

[0034] In some embodiments, the mass of the active agent is 4% to 6% of the mass of the EPDM rubber base material, for example, it can be 4%, 5% or 6%, or any value therebetween.

[0035] In some embodiments, the raw materials for preparing the low-temperature resistant EPDM rubber material further include an antioxidant for improving the heat-oxidative aging resistance of the rubber material.

[0036] In some embodiments, the antioxidant is one or more of antioxidant RD, antioxidant 445, and antioxidant ZMB.

[0037] In some embodiments, the antioxidant is a combination of antioxidant RD and antioxidant ZMB.

[0038] In some embodiments, the mass of the antioxidant is 1% to 2% of the mass of the EPDM rubber base material.

[0039] In some embodiments, the low-temperature resistant EPDM rubber material includes the following raw materials in parts by weight: 100 parts of EPDM rubber base material, 4 to 6 parts of activator, 1 to 2 parts of antioxidant, 10 to 30 parts of plasticizer, 40 to 70 parts of reinforcing agent, 3 to 6 parts of peroxide, 0.2 to 0.8 parts of sulfur, and 1 to 2 parts of cross-linking agent.

[0040] For the specific selection of the type or amount of each component, please refer to the above embodiment.

[0041] It should be understood that in the raw material system of this embodiment, the type or amount of the EPDM rubber base material, plasticizer, reinforcing agent, and vulcanizing agent can be reasonably adjusted according to known techniques and are not limited to the scope of the above-mentioned embodiment. At the same time, according to actual application needs, components such as co-crosslinking agents, activators, and antioxidants can be further added, and the present invention does not impose any restrictive provisions on the type or amount of these components. Furthermore, it is understood that the above-mentioned embodiment can be applied individually or in combination, and all fall within the scope of protection of the present invention.

[0042] The second embodiment of the present invention relates to a method for preparing the above-mentioned low-temperature resistant EPDM rubber material, comprising: mixing all the preparation raw materials, and vulcanizing to obtain the material.

[0043] The present invention does not impose any restriction on the mixing process, and a conventional mixing method can be used, for example, firstly plasticizing the EPDM rubber base material and then mixing it evenly with the other components.

[0044] In some embodiments, the method for preparing the low-temperature resistant EPDM rubber material comprises:

[0045] S1, plasticizing the EPDM rubber base material;

[0046] S2, adding part of the reinforcing agent and part of the plasticizer to the rubber material prepared in step S1 for a first mixing, and then adding the remaining reinforcing agent and the remaining plasticizer for a second mixing;

[0047] S3, adding the vulcanizing agent to the rubber material obtained in step S2, and vulcanizing after thinning to obtain the product.

[0048] In some embodiments, when the raw materials for preparing the low-temperature resistant EPDM rubber material also include the activator and / or the antioxidant, step S1 is: plasticizing the EPDM rubber base material, and then adding the activator and / or the antioxidant for pre-mixing.

[0049] In some embodiments, the pre-mixing temperature is 70-90° C., for example, it can be any value among 70° C., 80° C., 90° C., or any value in between.

[0050] In some embodiments, the pre-mixing time is 2 to 4 minutes, for example, 2 minutes, 3 minutes or 4 minutes.

[0051] In some embodiments, in step S1, the plasticizing temperature is 60-75°C, for example, it can be any value among 60°C, 65°C, 70°C, 75°C or any value in between.

[0052] In some embodiments, in step S1, the mastication time is 5 to 10 minutes, for example, it can be any value among 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, or any value in between.

[0053] In some embodiments, in step S2, the mass ratio of part of the reinforcing agent to the remaining reinforcing agent is 1:1 to 1.5, for example, it can be any value among 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value in between.

[0054] In some embodiments, in step S2, the mass ratio of part of the plasticizer to the remaining plasticizer is 1:1 to 1.5, for example, it can be any value among 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value in between any two.

[0055] In some embodiments, in step S2, the temperature of the first mixing is 90-115°C, for example, it can be any value among 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or any value in between.

[0056] In some embodiments, in step S2, the first mixing time is 3 to 5 minutes, for example, 3 minutes, 4 minutes or 5 minutes.

[0057] In some embodiments, in step S2, the temperature of the second mixing is 120-140°C, for example, it can be any value among 120°C, 130°C, 140°C or any value in between.

[0058] In some embodiments, in step S2, the second mixing time is 3 to 5 minutes, for example, 3 minutes, 4 minutes or 5 minutes.

[0059] In some embodiments, step S2 further includes filtering the rubber material obtained by the second mixing.

[0060] In some embodiments, the filtration mesh size is not less than 100 mesh.

[0061] In some embodiments, the filtration mesh size is not less than 130 mesh.

[0062] In some embodiments, the filtration is performed ≥ 2 times, and graded filtration can improve filtration efficiency and avoid screen clogging. It is understood that when multi-stage filtration is used, the filtration mesh size can be increased step by step until the target value is reached.

[0063] In some embodiments, the filtration is a two-stage filtration, wherein the mesh number of the first stage filtration is not less than 100 mesh, and the mesh number of the second stage filtration is not less than 130 mesh.

[0064] In some embodiments, the filtration temperature is 170-190°C, for example, it can be any value among 170°C, 180°C, 190°C or any value in between.

[0065] In some embodiments, the filtration is followed by standing at a temperature, for example, room temperature, for 16 to 24 hours.

[0066] In some embodiments, when the raw materials for preparing the low-temperature resistant EPDM rubber material also include the auxiliary cross-linking agent, step S3 is: adding the vulcanizing agent and the auxiliary cross-linking agent to the rubber material prepared in step S2, and vulcanizing after thinning to obtain the material.

[0067] In some embodiments, in step S3, the vulcanization temperature is 155-160° C., the time is 25-35 minutes, and the pressure is 10-14 MPa. Non-limiting examples of the vulcanization process include: a temperature of 155° C. or 160° C., or any value therebetween; a time of 25 minutes, 30 minutes, or 35 minutes, or any value therebetween; and a pressure of 10 MPa, 11 MPa, 12 MPa, 13 MPa, or 14 MPa, or any value therebetween.

[0068] In some embodiments, in step S3, the number of thin passes is 8 or more. Thin passes can improve dispersion uniformity. To better balance production efficiency and material properties, the number of thin passes can be selected to be 8 to 10 times.

[0069] In some embodiments, step S3 further comprises: before adding the vulcanizing agent and the auxiliary cross-linking agent, pre-thinning the rubber material obtained in step S2. The pre-thinning can be performed multiple times, for example, 2 to 5 times.

[0070] It can be understood that the above-mentioned preparation method embodiments can be applied individually or in combination, and all fall within the scope of protection of the present invention.

[0071] A third embodiment of the present invention relates to the use of the above-mentioned low-temperature resistant EPDM rubber material in the preparation of cable accessories or cables.

[0072] Since the above-mentioned low-temperature resistant EPDM rubber material has excellent low-temperature resistance and mechanical properties, it can better meet the application requirements of cable accessories or cables, especially can extend the service life in low-temperature environments and improve safety of use.

[0073] In some embodiments, the cable accessories include but are not limited to cable jackets, cable connectors, stress cones, and the like.

[0074] In this paper, DBP absorption value refers to the ability of carbon black to absorb dibutyl phthalate (DBP), which can reflect the structural state, specific surface area and oil absorption capacity of carbon black.

[0075] "Plurality" includes two or more than two.

[0076] "Room temperature" refers to 23±2.5°C.

[0077] When it comes to numerical ranges, all include the end values ​​and any subset ranges within the range; the above all include the number itself, for example, above 2 includes 2.

[0078] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0079] The following describes in detail embodiments of the present invention. The embodiments are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0080] In the following examples, the relevant raw materials are described as follows:

[0081] EPDM rubber base material: Dow Chemical 4520, ethylene content 50wt%, ENB content 4.9wt%, Mooney viscosity 20 (ML1+4, 125°C); reinforcing agent: carbon black, purchased from Imerys, DBP absorption value 100mL / 100g, specific surface area 70m2 / g, powdery appearance; plasticizer: TP-90B produced by Hallstar, USA, polyether, purchased from Shanghai Jinchangsheng, molecular weight 223, pour point <-60°C.

[0082] Unless otherwise specified, the raw materials or equipment involved are conventional raw materials or equipment that can be purchased commercially.

[0083] Example 1

[0084] A low-temperature resistant EPDM rubber material was prepared, and the raw materials for its preparation were calculated as follows in parts by weight:

[0085] EPDM rubber base material: 100 parts,

[0086] Zinc oxide: 5 parts,

[0087] Stearic acid: 1 part,

[0088] Antioxidant RD: 1 part,

[0089] Antioxidant ZMB: 1 part,

[0090] Plasticizer: 15 parts,

[0091] Carbon black: 60 parts,

[0092] Dicumyl peroxide: 5 parts,

[0093] Insoluble sulfur: 0.6 parts,

[0094] Triallyl isocyanurate: 1 part.

[0095] The preparation steps are as follows:

[0096] S1. Put the formulated amount of EPDM rubber base material into a pressure mixer and plasticate at 70°C for 8 minutes to break the rubber;

[0097] S2. Add the formulated amount of zinc oxide, stearic acid, antioxidant RD, and antioxidant ZMB into a pressure mixer and mix at 80°C for 3 minutes;

[0098] S3, add 1 / 2 of the formula amount of carbon black and 1 / 2 of the plasticizer and mix at 100°C for 3 minutes; then add the remaining carbon black and plasticizer and mix at 130°C for 4 minutes;

[0099] S4, the mixed rubber material is subjected to two-stage filtration, wherein the filtration temperature is 190 ° C, the mesh size of the first filtration is 100 mesh, the mesh size of the second filtration is 130 mesh, and the filtration is allowed to stand at room temperature for 24 hours;

[0100] S5. Put the cooled and parked material into an open mill and pass it through twice. Then add the formulated amount of dicumyl peroxide, triallyl isocyanurate and insoluble sulfur into the open mill and pass it through 10 times. Then, carry out vulcanization and sheeting: the vulcanization temperature is 160°C, the vulcanization time is 35 minutes, and the vulcanization pressure is 14 MPa.

[0101] Comparative Example 1

[0102] A low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that Dow Chemical 4520 was replaced with Ningbo SK501A (South Korean SK, ethylene content of 53 wt%).

[0103] Comparative Example 2

[0104] The low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that the Yirui carbon black was replaced with Cabot VXC-72 carbon black (DBP absorption value 240mL / 100g, specific surface area 270m 2 / g of granular carbon black).

[0105] Comparative Example 3

[0106] The low temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that the Yirui carbon black was replaced with Cabot M5 white carbon black (specific surface area 200m 2 / g of fumed silica).

[0107] Comparative Example 4

[0108] A low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that 2 / 3 of the mass of Yirui carbon black was replaced with superconductive carbon black (DBP absorption value 430 mL / 100 g).

[0109] Comparative Example 5

[0110] A low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that the polyether plasticizer was replaced with polyoxypropylene glycol PPG1000, which has a molecular weight of 960 and a pour point of less than -60°C.

[0111] Comparative Example 6

[0112] A low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that the polyether plasticizer was replaced with paraffin oil 300, which has a molecular weight of 280 and a pour point of -15°C.

[0113] Comparative Example 7

[0114] A low-temperature resistant EPDM rubber material was prepared by referring to the method of Example 1, except that insoluble sulfur was not added.

[0115] Test Case

[0116] The test method is as follows:

[0117] Hardness (Shore A): GB / T 531.1-2008.

[0118] Tensile strength at break, elongation at break: GB / T 528-2009, specimen type: Type 1 dumbbell specimen, tensile rate: 500 mm / min.

[0119] Tensile permanent set: GB / T 42279-2022, Specimen type: Type 1 dumbbell specimen with a width of 6 mm.

[0120] Compression set: GB / T 7759.1-2015, specimen type: cylinder with a diameter of 29 mm ± 0.5 mm and a height of 12.5 mm ± 0.5 mm.

[0121] Before testing, the sample equilibrium conditions are as follows:

[0122] 1. Under normal temperature conditions of 25℃, place the sample at a test temperature of 25±0.5℃ for 24 hours before testing;

[0123] 2. Under low temperature conditions of -40℃, the specimens shall be placed at a test temperature of -40±0.5℃ for 168h before testing. The tensile permanent deformation and compression permanent deformation shall be tested after being frozen at a constant temperature of -40℃ for 168h, then the load shall be removed and the specimens shall be kept at room temperature of 25±0.5℃ for 2h before testing.

[0124] The test results of Example 1 and Comparative Examples 1 to 7 are shown in Table 1.

[0125] Table 1

[0126]

[0127] As can be seen from Table 1, the low-temperature tensile permanent deformation (-40°C / tensile 200% / 168h) and low-temperature compression permanent deformation (-40°C / compression 25% / 168h) of the material of the embodiment of the present invention are both smaller than those of the other comparative examples; at -40°C, the increase in 50% modulus of elongation compared to room temperature is ≤50%, while the other comparative examples are all >50%; at -40°C, the increase in hardness compared to room temperature is ≤10, while the other comparative examples are all >10; at -40°C, the decrease in elongation at break compared to room temperature is ≤15%, while the other comparative examples are all >15%, which greatly improves the low-temperature resistance of the material.

[0128] In Comparative Example 1, the ethylene content is increased, the low-temperature hardening phenomenon is aggravated, the low-temperature tensile / compression permanent deformation is increased, and the hardness change value, 50% modulus change rate, and elongation at break change rate at -40°C are all higher.

[0129] Comparative Example 2 uses high-reinforcement carbon black with a high DBP value, and Comparative Example 4 uses superconducting carbon black with a high DBP value. The two have strong interactions with macromolecules and will limit the mobility of macromolecules. Comparative Example 3 uses fumed silica, which has fine particles and contains a large number of silanol groups on the surface. It has extremely strong polarity. The filler network formed by the hydrogen bonding of silanol groups makes the particles tend to aggregate, which will increase the resistance to the activity of the rubber material molecular chain, increase the material modulus, and reduce the material's rebound performance. The polyoxypropylene glycol plasticizer in Comparative Example 5 is not compatible with the EPDM rubber substrate, affecting the mobility of the rubber molecular chain. The paraffin oil plasticizer in Comparative Example 6 has a low freezing point and is difficult to effectively improve fluidity at low temperatures. Comparative Example 7 does not contain a sulfur vulcanizing agent. C-C rigid bonds are mainly formed between molecules. There are no polysulfide bonds formed by sulfur cross-linking. The molecular steric hindrance is large and the chain link mobility is poor.

[0130] From the above results, it can be seen that the EPDM rubber material of the embodiment has better low-temperature resistance, the overall performance of the rubber material is excellent, and can better meet the use requirements of products such as cable accessories under low-temperature conditions.

[0131] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. A low-temperature resistant EPDM rubber material, characterized in that: The preparation comprises the following raw materials: 100 parts of EPDM rubber base material, 4-6 parts of activator, 1-2 parts of antioxidant, 10-30 parts of plasticizer, 40-70 parts of reinforcing agent, 4-6 parts of peroxide, 0.2-0.8 parts of sulfur, and 1-2 parts of cross-linking agent; The mass content of ethylene monomer in the EPDM base material is 45% to 50%; the plasticizer is a polyether; the reinforcing agent is powdered carbon black with a DBP absorption value of 80 to 110 mL / 100 g, and the specific surface area of ​​the powdered carbon black is 60 to 100 m 2 / g; The plasticizer has a number average molecular weight of 200 to 500 and a solidification point of less than -60°C; The sulfur is selected from insoluble sulfur; The auxiliary cross-linking agent is selected from one or more of triallyl isocyanurate and 2-mercaptobenzothiazole; The mass of the auxiliary cross-linking agent is 1 / 5 to 1 / 3 of the mass of the peroxide.

2. The low-temperature resistant EPDM rubber material according to claim 1, characterized in that: The peroxide is selected from one or more of dicumyl peroxide and 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane; And / or, the mass content of the third monomer of the EPDM rubber base material is 2% to 10%; And / or, the EPDM rubber base material has an ML1+4 / 125°C Mooney viscosity of 15 to 25.

3. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The active agent is selected from one or more of zinc oxide and stearic acid.

4. The low-temperature resistant EPDM rubber material according to claim 1, characterized in that: The antioxidant is one or more of antioxidant RD, antioxidant 445, and antioxidant ZMB.

5. The method for preparing a low-temperature resistant EPDM rubber material according to any one of claims 1 to 4, characterized in that: include: S1, plasticizing the EPDM rubber base material; S2, adding part of the reinforcing agent and part of the plasticizer to the rubber material prepared in step S1 for a first mixing, and then adding the remaining reinforcing agent and the remaining plasticizer for a second mixing; S3, adding the peroxide and sulfur to the rubber material obtained in step S2, and vulcanizing after thinning; Wherein, when the raw materials for preparing the low-temperature resistant EPDM rubber material further include an activator and / or an antioxidant, step S1 further includes: after the mastication, adding the activator and / or the antioxidant for pre-mixing; When the raw materials for preparing the low-temperature resistant EPDM rubber material also include a cross-linking agent, step S3 is: adding the peroxide, the sulfur, and the cross-linking agent to the rubber material prepared in step S2, and vulcanizing after thinning to obtain the rubber material.

6. Use of the low-temperature resistant EPDM rubber material according to any one of claims 1 to 4 in the preparation of cable accessories or cables.

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