Low-temperature-resistant ethylene propylene diene monomer material as well as preparation method and application thereof

Abstract

The invention discloses a low-temperature-resistant ethylene propylene diene monomer material as well as a preparation method and application thereof. The low-temperature-resistant ethylene propylene diene monomer material is prepared from the following raw materials: an ethylene propylene diene monomer base material, a plasticizer, a reinforcing agent and a vulcanizing agent, wherein in the ethylene propylene diene monomer base material, the mass content of an ethylene monomer is 45%-50%; the plasticizer is polyether; the reinforcing agent is powdery carbon black of which the DBP (dibutyl phthalate) absorption value is 80 to 110 mL / 100g; the vulcanizing agent comprises peroxide and sulfur. Through raw material matching, the low temperature resistance of the material is remarkably improved, and the comprehensive performance of the rubber material is excellent. The invention also provides a preparation method and application of the low-temperature-resistant ethylene propylene diene monomer material.

Description

Technical Field

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

[0002] EPDM rubber is a terpolymer of ethylene, propylene and non-conjugated diene (third monomer). The main chain of the molecule is completely composed of saturated hydrocarbons with stable chemical structure. The ethylene and propylene monomer units are randomly arranged along the main chain. Even if a small amount of unsaturated double bonds are introduced on the side chain of the molecule, the molecular cohesion energy is low due to the absence of polar substituents in the molecule, which makes the molecular chain flexible and can maintain good resilience at room temperature. However, under low temperature conditions, the relaxation process of the molecular chain slows down sharply, and the elasticity of the rubber material will also decrease.

[0003] EPDM rubber products for 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 rubber increase, causing the working ability of rubber products to decrease. Especially in the northern market, rubber cable accessories lose their elastic properties due to being in low-temperature environments for a long time, resulting in gaps between rubber parts and 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 the mechanical properties.

[0006] The 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 aspect 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 aspect 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] The use of low-reinforcement carbon black with a smaller DBP absorption value can reduce the intermolecular force between carbon black and the rubber substrate, which can better ensure the mobility of the chain segments while reinforcing. Therefore, after filling with low-reinforcement carbon black, the hardness of the rubber material will be smaller, its modulus will be lower, the intermolecular force will be weaker, the mobility will be stronger, and the low-temperature resistance will be better.

[0012] The vulcanizer uses 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 activity of molecular chains.

[0014] By using a low-ethylene-content EPDM rubber base material, a mixed vulcanization system of peroxide and sulfur, and filling with low-reinforcing carbon black and polyether plasticizers, the low-temperature resistance is significantly improved while ensuring the mechanical properties. The results show that under -40°C conditions, the following can be achieved: 200% tensile permanent deformation ≤30%; 25% compression permanent deformation ≤40%; the increase in the tensile stress compared to room temperature, the change rate is ≤50%; the decrease in the elongation at break compared to room temperature, the change rate is ≤15%; the increase in the hardness (Shore A) compared to room temperature, the increase value is ≤10, which greatly improves the low-temperature resistance of the material and the comprehensive performance of the rubber is excellent.

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

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

[0017] Non-limiting examples of the third monomer include vinyl norbornene (ENB), dicyclopentadiene (DCPD), etc. ENB is more commonly used and can provide a higher crosslinking rate. DCPD has a cyclic structure, and the structure remains cyclic after crosslinking with a vulcanizing agent, has better mechanical stability, and can better maintain the inherent three-dimensional spatial structure between rubber molecules, thereby ensuring its resilience.

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

[0019] In some embodiments, the plasticizer has a number average molecular weight of 200 to 500 and a freezing point of less than -60° C. The smaller the molecular weight, the lower the viscosity, and the lower the freezing point, the better the fluidity even at low temperatures, and can act as a lubricant between macromolecules, further improving the mobility of the molecular chain.

[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 / g or any value between any two. A smaller specific surface area can reduce the gaps between the primary or secondary particles of carbon black, making the stacking more compact, reducing the impact on the mobility of the EPDM 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, in the vulcanizing agent, the mass of the peroxide 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 between any two of them, 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 between any two of them.

[0027] By adjusting the composition of the vulcanization system, controlling the degree of crosslinking, and the ratio of sulfur crosslinks and CC crosslinks in the rubber, the performance of the rubber can be further improved. Among them, the increase in the content of peroxide and sulfur will increase the crosslinking density of the material, but too high a crosslinking density will make the spatial network structure of the material more stable, the spatial steric hindrance of the molecular chain activity will increase, and the mechanical modulus will increase, which will reduce the resilience of the material; on the contrary, if the degree of crosslinking is low, the material's ability to resist external forces will decrease, affecting its ability to resist permanent deformation. By controlling the ratio of peroxide and sulfur, the role of sulfur crosslinks and CC crosslinks can be better exerted, making the rubber more stable and having better overall performance.

[0028] In some embodiments, the raw materials for preparing the low-temperature resistant EPDM rubber material also include a cross-linking aid, 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, it can be 1 / 5, 1 / 4 or 1 / 3, or any value between any two of them. 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 base material, the proportion of the co-crosslinking agent relative to the EPDM base material 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 mass 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 also 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, refer to the above-mentioned embodiment.

[0041] It should be understood that in the raw material system of this solution, the type or amount of EPDM rubber base material, plasticizer, reinforcing agent, and vulcanizing agent can be reasonably adjusted according to known technology, and is not limited to the scope of the above-mentioned embodiment. At the same time, according to the actual application needs, components such as co-crosslinking agent, activator, and antioxidant can be further added, and the present invention does not make any restrictive provisions on the type or amount of these components. Furthermore, it can be understood that the above-mentioned embodiments can be applied alone or in combination, and all belong to the protection scope 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 mixing process of the present invention is not restrictive, and a conventional mixing method can be used, for example, firstly plasticizing the EPDM rubber base material, and then mixing it with the other components uniformly.

[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 obtained 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 plasticating 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 any two of them.

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

[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 of 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or any value in between any two of them.

[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 any two of them.

[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 number is not less than 100 mesh.

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

[0062] In some embodiments, the number of filtrations is ≥ 2 times, and graded filtration can improve filtration efficiency and avoid screen clogging. It is understood that when multi-stage filtration is used, the mesh size of the filtration 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 meshes, and the mesh number of the second stage filtration is not less than 130 meshes.

[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 such as 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 obtained 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 min, and the pressure is 10-14 MPa. Non-limiting examples of the vulcanization process include, for example, a temperature of 155°C or 160°C, or any value therebetween; a time of 25 min, 30 min, or 35 min, 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 more than 8 times. Thin passes can improve dispersion uniformity. In order to better balance production efficiency and material performance, 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 number of pre-thinning can be 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 belong to the protection scope of the present invention.

[0071] A third aspect of the present invention relates to the use of the 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 environment and improve the safety of use.

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

[0074] In this article, 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, they include the end values ​​and any subset ranges within the range; the above include the number itself, for example, 2 and above include 2.

[0078] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0079] Embodiments of the present invention are described in detail below. The embodiments are exemplary and are only used to explain the present invention, but should not 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, freezing 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 by weight as follows:

[0085] EPDM rubber base material: 100 parts,

[0086] Zinc oxide: 5 parts,

[0087] Stearic acid: 1 part,

[0088] Anti-aging agent RD: 1 part,

[0089] Anti-aging agent 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 plasticize 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 carbon black and 1 / 2 of the plasticizer, mix at 100°C for 3 minutes; then add the remaining carbon black and plasticizer, 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 number of the filter for the first filtration is 100 mesh, the mesh number of the filter for the second filtration is 130 mesh, and the filtration is left 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 diisopropylbenzene peroxide, triallyl isocyanurate and insoluble sulfur into the open mill, pass it through 10 times, and then perform vulcanization and film making: the vulcanization temperature is 160°C, the vulcanization time is 35 minutes, and the vulcanization pressure is 14MPa.

[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 by Ningbo SK501A (Korea 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 had a molecular weight of 960 and a freezing point of <-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 had a molecular weight of 280 and a freezing point of -15°C.

[0113] Comparative Example 7

[0114] The 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 and elongation at break: GB / T 528-2009, specimen type: Type 1 dumbbell specimen, tensile rate: 500 mm / min.

[0119] Tensile permanent deformation: 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 balance conditions are as follows:

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

[0123] 2. Under low temperature conditions of -40℃, place the sample at the 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 -40℃ for 168h, and then the load shall be removed and 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] It can be seen from Table 1 that the low-temperature tensile permanent deformation (-40°C / stretching 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 other comparative examples; at -40°C, the increase in 50% elongation stress compared with room temperature has a change rate of ≤50%, and the other comparative examples are all >50%; at -40°C, the increase in hardness compared with room temperature is ≤10, and the other comparative examples are all >10; at -40°C, the decrease in elongation at break has a change rate of ≤15% compared with room temperature, and 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% elongation strength 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 activity 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 rebound performance. The polyoxypropylene glycol plasticizer in Comparative Example 5 is not compatible with the EPDM rubber substrate, which affects the activity 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 have a sulfur vulcanizer, and mainly forms CC rigid bonds between molecules. There are no polysulfide bonds formed by sulfur cross-linking, and the molecular steric hindrance is large, and the chain activity 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 rubber material has excellent comprehensive performance, 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 in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A low temperature resistant EPDM rubber material, characterized in that: The preparation includes the following raw materials: EPDM rubber base material, plasticizer, reinforcing agent, vulcanizing agent; Among them, the mass content of ethylene monomer in the EPDM rubber base material is 45% to 50%; the plasticizer is 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.

2. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The number average molecular weight of the plasticizer is 200 to 500, and the solidification point is less than -60°C; and / or the mass of the plasticizer is 10% to 30% of the mass of the EPDM rubber base material.

3. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The specific surface area of ​​the powdered carbon black is 60 to 100 m 2 / g; and / or, the mass of the powdered carbon black is 40% to 70% of the mass of the EPDM rubber base material.

4. 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 of the peroxide is 3% to 6% of the mass of the EPDM rubber base material; And / or, the sulfur is selected from insoluble sulfur; And / or, the mass of the sulfur is 0.2% to 0.8% of the mass of the EPDM rubber base material; And / or, the mass content of the third monomer of the EPDM rubber base material is 2% to 10%; And / or, the Mooney viscosity of the EPDM rubber base material is 15 to 25 (ML1+4, 125°C).

5. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The raw materials for preparing the low temperature resistant EPDM rubber material also include a cross-linking aid; Optionally, the auxiliary cross-linking agent is selected from one or more of triallyl isocyanurate and 2-mercaptobenzothiazole; Optionally, the mass of the auxiliary cross-linking agent is 1 / 5 to 1 / 3 of the mass of the peroxide in the vulcanizing agent.

6. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The raw materials for preparing the low temperature resistant EPDM rubber material also include an activator; Optionally, the active agent is selected from one or more of zinc oxide and stearic acid; Optionally, the mass of the active agent is 4% to 6% of the mass of the EPDM rubber base material.

7. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The raw materials for preparing the low-temperature resistant EPDM rubber material also include an antioxidant; Optionally, the mass of the antioxidant is 1% to 2% of the mass of the EPDM rubber base material; Optionally, the antioxidant is one or more of antioxidant RD, antioxidant 445, and antioxidant ZMB.

8. The low temperature resistant EPDM rubber material according to claim 1, characterized in that: The preparation method comprises the following raw materials in parts by weight: 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, 3-6 parts of peroxide, 0.2-0.8 parts of sulfur, 1-2 parts of cross-linking agent; Among them, the mass content of ethylene monomer in the EPDM rubber base material is 45% to 50%; the plasticizer is polyether; and the reinforcing agent is powdered carbon black with a DBP absorption value of 80 to 110 mL / 100 g.

9. The method for preparing the low temperature resistant EPDM rubber material according to any one of claims 1 to 8, 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 obtained 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 vulcanizing agent 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 vulcanizing agent and the cross-linking agent to the rubber material obtained in step S2, and vulcanizing after thinning to obtain the material.

10. Use of the low-temperature resistant EPDM rubber material according to any one of claims 1 to 8 in the preparation of cable accessories or cables.

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