An EPDM buffer block material with excellent low-pressure-low-temperature performance and a preparation method thereof

Abstract

The invention discloses an EPDM buffer block material with excellent low-pressure-to-low-temperature performance and a preparation method thereof, which belongs to the technical field of EPDM buffer block materials. The material comprises the following raw materials in parts by weight: 40-60 parts of EPDM rubber, 40-60 parts of EBT rubber, 5-10 parts of zinc oxide, 2-6 parts of antioxidant, and 935P internal release agent. 1‑3 parts, 10‑20 parts of plasticizer, 50‑60 parts of filler, 3‑5 parts of cross-linking agent, and 11‑13 parts of dicumyl peroxide; the filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1‑2:3‑4, the plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 1‑2:1:1, EPDM rubber and EBT rubber are mixed, and modified zirconium tungstate and compound plasticizer are introduced, so that the low temperature resistance of the finally obtained rubber product is reduced to below ‑50°C, and the rubber product has good mechanical properties and compression deformation properties.

Description

Technical Field

[0001] The invention belongs to the technical field of EPDM buffer block materials, and in particular relates to an EPDM buffer block material with excellent low-pressure to low-temperature performance and a preparation method thereof. Background Art

[0002] Compared with natural rubber (NR), styrene-butadiene rubber (SBR) and chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM) has excellent elasticity and extremely excellent weather resistance, ozone resistance and UV aging resistance. Therefore, it is widely used as door and window sealing strips or brake buffer blocks for vehicles such as automobiles, subways and high-speed trains. However, these rubber products need to work at low ambient temperatures. At low temperatures, the molecular chain relaxation process slows down sharply, the hardness, modulus and intramolecular friction of the vulcanized rubber increase, and the elasticity decreases significantly, resulting in a decrease in the functional capabilities of the rubber products, especially under dynamic conditions.

[0003] In this regard, a low-temperature compression permanent deformation resistant EPDM rubber material and a preparation method thereof are announced with authorization announcement number CN114672101B. The rubber material includes the following raw materials in parts by weight: 80-90 parts of EPDM rubber, 10-20 parts of silica gel, 45-55 parts of carbon black, 1-2 parts of antioxidant, 3-8 parts of zinc oxide, 0.5-1.5 parts of stearic acid, 15-30 parts of plasticizer, 1-2 parts of hydrogen-containing silicone oil, 3-4 parts of vulcanizing agent, 1-2 parts of cross-linking agent, 3-4 parts of coupling agent, and 0.4-0.6 parts of lubricant. Silicone rubber and EPDM rubber are compounded to improve the low-temperature compression permanent deformation resistance of EPDM rubber, but the lowest TR10 is -47.4℃, and there is still a lot of room for improvement, so it is difficult to apply to more severe cold areas. Summary of the invention

[0004] The object of the present invention is to provide an EPDM buffer block material with excellent low-pressure-to-low-temperature performance and a preparation method thereof, in order to solve the problem of high low-temperature compression permanent deformation of existing EPDM products.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An EPDM buffer block material with excellent low-pressure-to-low-temperature performance, comprising the following raw materials in parts by weight:

[0007] 40-60 parts of EPDM rubber, 40-60 parts of EBT rubber, 5-10 parts of zinc oxide, 2-6 parts of antioxidant, 1-3 parts of internal release agent 935P, 10-20 parts of plasticizer, 50-60 parts of filler, 3-5 parts of cross-linking agent, and 11-13 parts of diisopropylbenzene peroxide.

[0008] Furthermore, the EPDM rubber has a Mooney viscosity of 80 and an ethylene content of 55-70%, preferably Keltan 8550 or Keltan 8570.

[0009] Furthermore, the EBT rubber is ethylene-butadiene rubber, preferably K9330M produced by Japan Mitsui Chemical Company.

[0010] Furthermore, the antioxidant is composed of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-di(phenylisopropyl)diphenylamine in a mass ratio of 1-3:1-3.

[0011] Furthermore, the plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 1-2:1:1.

[0012] Furthermore, the filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1-2:3-4.

[0013] Furthermore, the auxiliary cross-linking agent is trimethylolpropane trimethacrylate.

[0014] Furthermore, the modified zirconium tungstate is zirconium tungstate modified by silane coupling agent KH-570.

[0015] Furthermore, the preparation process of the modified zirconium tungstate is as follows:

[0016] The zirconium tungstate powder and ethanol solution were ultrasonically mixed for 10 minutes, and then the coupling agent KH-570 was added. The mixture was stirred at room temperature for 2-4 hours, and then dried at 110°C to constant weight. The dosage ratio of the zirconium tungstate powder, ethanol solution and coupling agent KH-570 was 10g: 100-200mL: 0.2-0.5g.

[0017] Furthermore, the mass fraction of the ethanol solution is 60-80%.

[0018] Furthermore, the average particle size of the zirconium tungstate powder is 0.5-3.0 μm.

[0019] The preparation method of the above-mentioned EPDM buffer block material with excellent low-pressure to low-temperature performance comprises the following steps:

[0020] S1. Put EPDM rubber, EBT rubber, zinc oxide, antioxidant, internal mold release agent 935P and plasticizer into a mixer according to the proportion and mix them at 85-95°C. Then add fillers and mix them at 135-145°C. When the temperature reaches 112-117°C and 121-127°C, lift the plug and discharge the rubber to obtain a mixed rubber.

[0021] S2, after the rubber mix obtained in S1 is left to stand for 8-16 hours, dicumyl peroxide and a cross-linking agent are added, and the mixture is mixed to 115-120° C. and then discharged to obtain a final rubber mix, wherein the plug lifting operation is performed when the temperature is 95-105° C.;

[0022] S3. The final rubber compound prepared in S2 is formed and sent to a vulcanizer for vulcanization. The vulcanization temperature of the primary vulcanization is 170-180°C, the vulcanization time is 6-9 minutes, and the vulcanization is completed to obtain an EPDM buffer block material with excellent low-pressure to low-temperature performance.

[0023] Beneficial effects of the present invention:

[0024] 1. EBT rubber is a polymer synthesized by metallocene catalysis of ethylene, butene and the third monomer 5-ethylidene-2-norbornene, and has good low-temperature performance and processing performance. The present invention mixes EBT rubber and EPDM rubber for use, which solves the problem that the mixed rubber obtained by using EBT rubber alone is not easy to store and use (after mixing, EBT is easy to stick and flow out of the storage cage due to its low Mooney and good fluidity), and also solves the problem that EPDM rubber has poor low-temperature performance when used alone, so that the low-temperature resistance of the final rubber product is reduced to below -50°C, and has good mechanical properties and compression deformation properties.

[0025] 2. The compound product of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate is used as a plasticizer to play a synergistic role. On the one hand, it reduces the interaction force between rubber macromolecules and improves their kinetic activity, thereby improving the low-temperature shrinkage performance. On the other hand, it reduces the viscosity of the rubber and improves plasticity, which is beneficial for processing. In addition, polyethylene glycol 4000 has excellent dispersibility and wettability, which can improve the dispersion of fillers in rubber and help ensure that rubber products have good mechanical properties. Dioctyl phthalate can hinder the agglomeration of paraffin oil at low temperatures and the crystallization of the ethylene end in EPDM rubber, thereby improving the shrinkage of rubber products at low temperatures.

[0026] 3. Using a compound of modified zirconium tungstate and SP5000 carbon black as filler is more conducive to obtaining rubber products with good shrinkage at low temperatures. The reasons are: first, the negative thermal expansion property of zirconium tungstate can offset the shrinkage of rubber due to temperature reduction to a certain extent, thereby maintaining its dimensional stability; second, the surface of the modified zirconium tungstate contains unsaturated double bonds, which can be cross-linked with the rubber material to increase the cross-linking density. The cross-linking network structure is dense and not easy to deform; however, the proportion of modified zirconium tungstate needs to be strictly controlled. If the proportion is too low, the cross-linking density will increase slightly, and the improvement effect of low-temperature shrinkage performance will not be obvious. If the proportion is too high, the cross-linking density will be too large, which will increase the brittleness of rubber products under low temperature conditions, and also lead to poor low-temperature resistance of rubber products. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples, the EPDM rubber has a Mooney viscosity of 80, an ethylene content of 55%, and a brand name of Keltan 8550. The EBT rubber is ethylene-butadiene rubber, specifically K9330M produced by Mitsui Chemical Co., Ltd. of Japan.

[0029] Example 1

[0030] An EPDM buffer block material with excellent low-pressure-to-low-temperature performance, comprising the following raw materials in parts by weight:

[0031] 40 parts of EPDM rubber, 60 parts of EBT rubber, 5 parts of zinc oxide, 2 parts of antioxidant, 1 part of internal release agent 935P, 10 parts of plasticizer, 50 parts of filler, 3 parts of trimethylolpropane trimethacrylate, and 11 parts of diisopropylbenzene peroxide.

[0032] The antioxidant is composed of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-di(phenylisopropyl)diphenylamine in a mass ratio of 1:1.

[0033] The plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 1:1:1.

[0034] The filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1:3.

[0035] The preparation process of the modified zirconium tungstate is as follows:

[0036] 10 g of zirconium tungstate powder and 100 mL of 60% ethanol solution were ultrasonically mixed for 10 min, and then 0.2 g of coupling agent KH-570 was added. The mixture was stirred at room temperature for 2 h, and then dried at 110 °C to constant weight.

[0037] The average particle size of the zirconium tungstate powder is 0.5-3.0 μm.

[0038] The preparation method of the above-mentioned EPDM buffer block material with excellent low-pressure to low-temperature performance comprises the following steps:

[0039] S1. Put EPDM rubber, EBT rubber, zinc oxide, antioxidant, internal mold release agent 935P and plasticizer into a banbury mixer according to the proportion and mix them at 85°C. Then add fillers and mix them at 135°C. When the temperature reaches 112°C and 121°C, lift the plug and discharge the rubber to obtain a mixed rubber.

[0040] S2, after the rubber mix obtained in S1 is left to stand for 8 hours, dicumyl peroxide and trimethylolpropane trimethacrylate are added, and the mixture is mixed to 115° C. and then discharged to obtain the final rubber mix, wherein the plug lifting operation is performed at a temperature of 95° C.;

[0041] S3. The final rubber compound prepared in S2 is formed and sent to a vulcanizer for vulcanization. The vulcanization temperature of the primary vulcanization is 170°C, the vulcanization time is 6 minutes, and the vulcanization is completed to obtain an EPDM buffer block material with excellent low-pressure to low-temperature performance.

[0042] Example 2

[0043] An EPDM buffer block material with excellent low-pressure-to-low-temperature performance, comprising the following raw materials in parts by weight:

[0044] 50 parts of EPDM rubber, 50 parts of EBT rubber, 8 parts of zinc oxide, 4 parts of antioxidant, 2 parts of internal release agent 935P, 15 parts of plasticizer, 55 parts of filler, 4 parts of trimethylolpropane trimethacrylate, and 12 parts of diisopropylbenzene peroxide.

[0045] The antioxidant is composed of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-di(phenylisopropyl)diphenylamine in a mass ratio of 1:3.

[0046] The plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 2:1:1.

[0047] The filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1:4.

[0048] The preparation process of the modified zirconium tungstate is as follows:

[0049] 10 g of zirconium tungstate powder and 200 mL of 80% ethanol solution were ultrasonically mixed for 10 min, and then 0.5 g of coupling agent KH-570 was added. The mixture was stirred at room temperature for 4 h, and then dried at 110 °C to constant weight.

[0050] The average particle size of the zirconium tungstate powder is 0.5-3.0 μm.

[0051] The preparation method of the above-mentioned EPDM buffer block material with excellent low-pressure to low-temperature performance comprises the following steps:

[0052] S1. Put EPDM rubber, EBT rubber, zinc oxide, antioxidant, internal mold release agent 935P and plasticizer into a banbury mixer according to the proportion and mix them at 90°C. Then add fillers and mix them at 140°C. When the temperature reaches 115°C and 125°C, lift the plug and discharge the rubber to obtain a mixed rubber.

[0053] S2, after the rubber mix obtained in S1 is left to stand for 10 hours, dicumyl peroxide and trimethylolpropane trimethacrylate are added, and the mixture is mixed to 118° C. and then discharged to obtain the final rubber mix, wherein the plug lifting operation is performed at a temperature of 100° C.;

[0054] S3. The final rubber compound prepared in S2 is formed and sent to a vulcanizer for vulcanization. The vulcanization temperature of the primary vulcanization is 175°C, the vulcanization time is 8 minutes, and the vulcanization is completed to obtain an EPDM buffer block material with excellent low-pressure to low-temperature performance.

[0055] Example 3

[0056] An EPDM buffer block material with excellent low-pressure-to-low-temperature performance, comprising the following raw materials in parts by weight:

[0057] 60 parts of EPDM rubber, 40 parts of EBT rubber, 10 parts of zinc oxide, 6 parts of antioxidant, 3 parts of internal release agent 935P, 20 parts of plasticizer, 60 parts of filler, 5 parts of trimethylolpropane trimethacrylate, and 13 parts of diisopropylbenzene peroxide.

[0058] The antioxidant is composed of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-di(phenylisopropyl)diphenylamine in a mass ratio of 3:1.

[0059] The plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 2:1:1.

[0060] The filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1:2.

[0061] The preparation process of the modified zirconium tungstate is as follows:

[0062] 10 g of zirconium tungstate powder and 200 mL of 80% ethanol solution were ultrasonically mixed for 10 min, and then 0.5 g of coupling agent KH-570 was added. The mixture was stirred at room temperature for 4 h and then dried at 110 °C to constant weight.

[0063] The average particle size of the zirconium tungstate powder is 0.5-3.0 μm.

[0064] The preparation method of the above-mentioned EPDM buffer block material with excellent low-pressure to low-temperature performance comprises the following steps:

[0065] S1. Put EPDM rubber, EBT rubber, zinc oxide, antioxidant, internal mold release agent 935P and plasticizer into a mixer according to the proportion and mix them at 95°C. Then add fillers and mix them at 145°C. When the temperature reaches 117°C and 127°C, lift the plug and discharge the rubber to obtain a mixed rubber.

[0066] S2, after the rubber mix obtained in S1 is left to stand for 16 hours, dicumyl peroxide and trimethylolpropane trimethacrylate are added, and the mixture is mixed to 120° C. and then discharged to obtain the final rubber mix, wherein the plug lifting operation is performed at a temperature of 100° C.;

[0067] S3. The final rubber compound prepared in S2 is formed and sent to a vulcanizer for vulcanization. The vulcanization temperature of the primary vulcanization is 175°C, the vulcanization time is 9 minutes, and the vulcanization is completed to obtain an EPDM buffer block material with excellent low-pressure to low-temperature performance.

[0068] Comparative Example 1

[0069] The modified zirconium tungstate in Example 1 is replaced by zirconium tungstate powder, the average particle size of the zirconium tungstate powder is 0.5-3.0 μm, and the other raw materials and preparation process are the same as in Example 1.

[0070] Comparative Example 2

[0071] Compared with Example 1, the total weight of the filler is kept unchanged, and the "filler consists of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1:4" in Example 1 is modified to "the filler consists of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 0.9:4.1", and the remaining raw materials and preparation process are the same as Example 1.

[0072] Comparative Example 3

[0073] Compared with Example 3, the total weight of the filler is kept unchanged, and the "filler consists of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1:2" in Example 3 is modified to "the filler consists of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1.1:1.9", and the remaining raw materials and preparation process are the same as Example 1.

[0074] Comparative Example 4

[0075] Compared with Example 1, the total weight of the plasticizer is kept unchanged, dioctyl phthalate is not added, and the mass ratio of polyethylene glycol 4000 to paraffin oil KP6030 is 1:1. The remaining raw materials and preparation process are also the same as in Example 1.

[0076] Comparative Example 5

[0077] Compared with Example 1, the total weight of the plasticizer is kept unchanged, polyethylene glycol 4000 is not added, and the mass ratio of dioctyl phthalate to paraffin oil KP6030 is 1:1. The remaining raw materials and preparation process are also the same as in Example 1.

[0078] Comparative Example 6

[0079] Compared with Example 1, the total weight of the plasticizer is kept unchanged, paraffin oil KP6030 is not added, and the mass ratio of dioctyl phthalate to polyethylene glycol 4000 is 1:1. The remaining raw materials and preparation process are also the same as in Example 1.

[0080] The performance tests of the buffer block materials obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were performed. The Shore A hardness was tested in accordance with GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber Part 1: Shore durometer method (Shore hardness)", the tensile strength and elongation at break were tested in accordance with GB / T 528-2009 "Test for tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the compression set was tested in accordance with GB / T 7759.2-2014 "Determination of compression set of vulcanized rubber or thermoplastic rubber Part 2: Under low temperature conditions", the low temperature shrinkage performance test was carried out in accordance with GB / T7758-2020, and TR10 corresponds to the temperature at which the sample shrinks by 10%;

[0081] The results are shown in Table 1:

[0082] Table 1

[0083]

[0084] It can be seen from the data recorded in Table 1 that the comprehensive performance of the buffer block materials obtained in Examples 1-3 is better than that in Comparative Examples 1-6. Specifically, it can be seen from the test results of Example 1 and Comparative Example 1 that when the modified zirconium tungstate is replaced with zirconium tungstate powder, the mechanical properties and low-temperature resistance of the rubber material are reduced to varying degrees, among which the low-temperature compression permanent deformation and TR10 are significantly reduced, indicating that the treatment of zirconium tungstate powder with coupling agent KH-570 is beneficial to improving the mechanical properties and low-temperature resistance of the EPDM buffer block material. It can be seen from the test results in Example 1 and Comparative Example 2, Example 3 and Comparative Example 3 that the proportion of modified zirconium tungstate should be strictly controlled. Too high or too low will have an adverse effect on the low-temperature performance of the buffer material. It can be seen from the test results of Example 1 and Comparative Example 4, Comparative Example 5, and Comparative Example 6 that there is a synergistic effect between polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate, and using any two of them alone cannot achieve a good effect.

[0085] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An EPDM buffer block material with excellent low-pressure and low-temperature performance, characterized in that: It includes the following raw materials in parts by weight: 40-60 parts of EPDM rubber, 40-60 parts of EBT rubber, 5-10 parts of zinc oxide, 2-6 parts of antioxidant, 1-3 parts of internal release agent 935P, 10-20 parts of plasticizer, 50-60 parts of filler, 3-5 parts of cross-linking agent, 11-13 parts of dicumyl peroxide; The filler is composed of modified zirconium tungstate and SP5000 carbon black in a mass ratio of 1-2:3-4; The plasticizer is composed of polyethylene glycol 4000, paraffin oil KP6030 and dioctyl phthalate in a mass ratio of 1-2:1:1; The modified zirconium tungstate is zirconium tungstate modified by silane coupling agent KH-570.

2. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 1, characterized in that: The preparation process of the modified zirconium tungstate is as follows: The zirconium tungstate powder and the ethanol solution were ultrasonically mixed for 10 minutes, and then the coupling agent KH-570 was added, and the mixture was stirred at room temperature for 2-4 hours, and then dried at 110°C to constant weight.

3. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 2, characterized in that: The dosage ratio of zirconium tungstate powder, ethanol solution and coupling agent KH-570 is 10g:100-200mL:0.2-0.5g.

4. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 2, characterized in that: The average particle size of the zirconium tungstate powder is 0.5-3.0 μm.

5. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 1, characterized in that: The Mooney viscosity of the EPDM rubber is 80, and the ethylene content is 55-70%.

6. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 1, characterized in that: The EBT rubber is ethylene-butadiene rubber.

7. The EPDM buffer block material with excellent low pressure and low temperature performance according to claim 1, characterized in that: The antioxidant is composed of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-di(phenylisopropyl)diphenylamine in a mass ratio of 1-3:1-3.

8. A method for preparing an EPDM buffer block material with excellent low-pressure and low-temperature performance, characterized in that: The method for preparing the EPDM buffer block material with excellent low pressure to low temperature performance as claimed in any one of claims 1 to 7 comprises the following steps: S1. Put EPDM rubber, EBT rubber, zinc oxide, antioxidant, internal mold release agent 935P and plasticizer into a mixer according to the proportion and mix them at 85-95°C. Then add fillers and mix them at 135-145°C. When the temperature reaches 112-117°C and 121-127°C, lift the plug and discharge the rubber to obtain a mixed rubber. S2, after the rubber mix obtained in S1 is left to stand for 8-16 hours, dicumyl peroxide and a cross-linking agent are added, and the mixture is mixed to 115-120° C. and then discharged to obtain a final rubber mix, wherein the plug lifting operation is performed when the temperature is 95-105° C.; S3. The final rubber compound prepared in S2 is formed and sent to a vulcanizer for vulcanization. The vulcanization temperature of the primary vulcanization is 170-180°C, the vulcanization time is 6-9 minutes, and the vulcanization is completed to obtain an EPDM buffer block material with excellent low-pressure to low-temperature performance.

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