Ethylene-propylene-diene monomer raw rubber and preparation method thereof

Abstract

The invention provides an ethylene-propylene-diene monomer raw rubber and a preparation method thereof, and belongs to the technical field of polymer composites.The preparation method comprises the following steps that S1, ethylene, propylene, dicyclopentadiene and a solvent are subjected to dehydration and deoxidation pretreatment; s2, adding a vulcanizing agent, a catalyst and an activating agent into the pretreated raw materials, uniformly mixing, and then carrying out vacuum defoaming treatment; s3, pouring the uniformly mixed material into a mold, and pre-curing under heating and pressurizing conditions; and S4, after pre-curing, main curing continues to be conducted under heating and pressurizing. The production process is short, the production efficiency is high, the process of each step is controllable, and the production cost of the ethylene-propylene-diene monomer raw rubber is remarkably reduced. By controlling the weight ratio of the raw materials in the ethylene-propylene-diene monomer raw rubber, on the premise of meeting the production requirements of high efficiency and low cost, various mechanical performance test indexes of the prepared ethylene-propylene-diene monomer raw rubber meet the national standard requirements.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, and more specifically, relates to a raw ethylene propylene diene monomer (EPDM) rubber and its preparation method. Background Technology

[0002] Ethylene propylene diene monomer (EPDM) rubber is a terpolymer of ethylene, propylene, and non-conjugated dienes. Since its successful development, EPDM rubber has been widely used due to its excellent properties such as low density and good weather resistance.

[0003] EPDM production technology has long been dominated by a few international giants such as Dow Chemical, ExxonMobil, Lanxess, and Mitsui Chemicals, who hold core patents on catalysts and polymerization processes. Currently, my country has a strong demand for EPDM raw rubber, but its high-end production capacity is insufficient, leading to a heavy reliance on imports. This results in high operating costs for companies that depend on EPDM raw rubber production. The high raw material costs of EPDM raw rubber are forcing companies to develop new, low-cost alternatives.

[0004] However, existing technologies for preparing EPDM raw rubber still suffer from problems such as slow vulcanization speed, low production efficiency, or narrow processing temperature range leading to greater difficulty in process control. These issues make it difficult for existing EPDM raw rubber preparation processes to meet the requirements of high-efficiency production and low cost. Summary of the Invention

[0005] The purpose of this invention is to provide a raw EPDM rubber and its preparation method to solve the technical problems of low production efficiency and high cost in the existing EPDM raw rubber preparation process.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for preparing EPDM raw rubber, comprising the following steps: S1. Pre-treat ethylene, propylene, dicyclopentadiene and solvent by dehydration and deoxygenation; S2. Add sulfiding agent, catalyst, and activator to the pretreated raw material and mix well, then perform vacuum degassing treatment; S3. Pour the mixed material into the mold and pre-cur it under heating and pressure. S4. After the pre-curing, the main curing continues under heating and pressure.

[0007] Furthermore, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 30-50 parts; Acrylic: 50-70 parts; Dicyclopentadiene: 2-8 parts; Vulcanizing agent: 1-5 parts; Catalyst: 2-5 parts; Activator: 1~1.5 parts Solvent: 6-9 parts.

[0008] Furthermore, the vulcanizing agent is dicumyl peroxide, the catalyst is a Ziegler-Natta catalyst, the activator is vinyltris(2-methoxyethoxy)silane, and the solvent is n-hexane.

[0009] Furthermore, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 40 parts; Acrylic: 60 parts; Dicyclopentadiene: 6 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0010] Furthermore, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 30 parts; Acrylic: 70 parts; Dicyclopentadiene: 7 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0011] Furthermore, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 50 parts; Acrylic: 50 parts; Dicyclopentadiene: 5 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0012] Furthermore, the pre-curing temperature is 80~100 ℃, the pressure is 7~10 bar, and the time is 30~40 min.

[0013] Furthermore, the primary curing temperature is 110~120 ℃, the pressure is 7~10 bar, and the time is 120~130 min.

[0014] Furthermore, the vacuum degassing treatment takes 3 to 5 minutes.

[0015] In a second aspect, the present invention provides a raw ethylene propylene diene monomer (EPDM) rubber, which is obtained by any of the preparation methods described above.

[0016] Compared with the prior art, the present invention has the following technical effects: The present invention discloses a method for preparing EPDM raw rubber by pretreating and mixing the raw materials, followed by vacuum degassing, pre-curing and primary curing to complete the preparation of EPDM raw rubber. The production process is short, the production efficiency is high, and the process of each step is controllable, which significantly reduces the production cost of EPDM raw rubber.

[0017] The present invention discloses a method for preparing EPDM raw rubber. By controlling the weight ratio of each raw material in the EPDM raw rubber, the method ensures that the various mechanical properties of the prepared EPDM raw rubber meet the national standard requirements while meeting the requirements of high efficiency and low cost production. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a process flow diagram of a method for preparing EPDM raw rubber provided in Embodiment 1 of the present invention. Detailed Implementation

[0020] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0022] This invention provides a method for preparing EPDM raw rubber, comprising the following steps: S1. Raw material refining: Ethylene, propylene, dicyclopentadiene (DCPD) and solvent are pretreated by dehydration and deoxygenation; S2. Stir evenly and degas under vacuum: Add vulcanizing agent, catalyst and activator to the pretreated raw material and mix evenly, then perform vacuum degassing treatment; S3. Pre-curing: Pour the mixed material into the mold and pre-cur it under heating and pressure. S4. Primary Curing: After pre-curing, primary curing continues under heat and pressure.

[0023] In step S1 above, hexane can be used as the solvent. By pretreating the raw materials by dehydration and deoxygenation, the catalyst can be prevented from being poisoned in the presence of trace amounts of water, oxygen and other impurities, thus ensuring the smooth and efficient progress of the subsequent catalytic reaction.

[0024] In step S2 above, the vulcanizing agent is dicumyl peroxide, the catalyst is Ziegler-Natta catalyst, and the activator is vinyltris(2-methoxyethoxy)silane. The vacuum degassing treatment time is 3-5 min. Vacuum degassing removes trace amounts of air mixed into the raw materials during stirring, ensuring that the prepared EPDM raw rubber has good mechanical properties.

[0025] In step S3 above, the pre-curing temperature is 80~100 ℃, the pressure is 7~10 bar, and the time is 30~40 min. By controlling the pre-curing temperature, pressure, and time, the raw rubber product undergoes a preliminary curing process, preparing it for subsequent main curing.

[0026] In step S4 above, the primary curing temperature is 110~120 ℃, the pressure is 7~10 bar, and the time is 120~130 min. By controlling the primary curing temperature, pressure, and time, the raw rubber is prepared into a rubbery state, which can then be molded into a product, facilitating corresponding performance tests.

[0027] In this embodiment of the invention, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 30-50 parts; Acrylic: 50-70 parts; Dicyclopentadiene: 2-8 parts; Vulcanizing agent: 1-5 parts; Catalyst: 2 parts; Activator: 1~1.5 parts Solvent: 9 parts.

[0028] In one embodiment, the raw materials in the EPDM raw rubber are formulated in the following weight proportions: Ethylene: 40 parts; Acrylic: 60 parts; Dicyclopentadiene: 6 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0029] In another embodiment, the raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 30 parts; Acrylic: 70 parts; Dicyclopentadiene: 7 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0030] In another embodiment, the raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 50 parts; Acrylic: 50 parts; Dicyclopentadiene: 5 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

[0031] The present invention discloses a method for preparing EPDM raw rubber by pretreating and mixing the raw materials, followed by vacuum degassing, pre-curing and primary curing to complete the preparation of EPDM raw rubber. The production process is short, the production efficiency is high, and the process of each step is controllable, which significantly reduces the production cost of EPDM raw rubber.

[0032] The method for preparing EPDM raw rubber according to an embodiment of the present invention controls the weight ratio of each raw material in the EPDM raw rubber, and the various mechanical performance test indicators of the prepared EPDM raw rubber meet the requirements of national standards under the premise of meeting the requirements of high efficiency and low cost production.

[0033] The following examples illustrate a method for preparing EPDM raw rubber and its preparation according to embodiments of the present invention. Example 1

[0034] Example 1 of this invention provides a raw EPDM rubber and its preparation method, the process flow is as follows: Figure 1 As shown, it includes the following steps: Raw material refining: 40 parts of high-purity ethylene, 60 parts of propylene, 6 parts of DCPD and 9 parts of n-hexane are subjected to deep dehydration and deoxygenation treatment.

[0035] Stirring: The treated ethylene, propylene, DCPD, and n-hexane are placed in a clean, dry beaker and mixed. One part dicumyl peroxide is added, and the mixture is first stirred briefly with a glass rod to achieve a uniform mixture. Then, two parts Ziegler-Natta catalyst and one part vinyltris(2-methoxyethoxy)silane are added to promote the polymerization reaction. Finally, the mixture is thoroughly stirred with a stirrer to achieve complete mixing.

[0036] Vacuum degassing: The mixed reagents are placed in a vacuum degassing machine for degassing, which takes 3-5 minutes. The mixture after degassing will have a very viscous consistency.

[0037] Pre-curing: First, apply a layer of silicone oil to the mold to facilitate demolding later. Pour the vacuum-degassed mixture into the mold, first using a beaker to pour most of it in, then using a dropper to fill in the rest. After pouring into the mold, preheat the heating and pressurizing oven to 80°C. Place the mold inside and pressurize it to 7-10 bar, maintaining the temperature at 80°C for half an hour. After half an hour, the mixture will appear as a viscous white gel.

[0038] Primary curing: Then heat to 120°C and maintain at 7-10 bar for two hours. After heating, it will be in a molten rubber state. Remove it and observe the state of the raw insulating adhesive. Let it rest at room temperature, and then conduct the corresponding tests. Example 2

[0039] Example 2 of this invention provides a raw EPDM rubber and its preparation method, comprising the following steps: Raw material refining: 30 parts of high-purity ethylene, 70 parts of propylene, 7 parts of DCPD and 9 parts of n-hexane are subjected to deep dehydration and deoxygenation treatment.

[0040] Stirring: The treated ethylene, propylene, DCPD, and n-hexane are placed in a clean, dry beaker and mixed. One part dicumyl peroxide is added, and the mixture is first stirred briefly with a glass rod to achieve a uniform mixture. Then, two parts Ziegler-Natta catalyst and one part vinyltris(2-methoxyethoxy)silane are added to promote the polymerization reaction. Finally, the mixture is thoroughly stirred with a stirrer to achieve complete mixing.

[0041] Vacuum degassing: The mixed reagents are placed in a vacuum degassing machine for degassing, which takes 3-5 minutes. The mixture after degassing will have a very viscous consistency.

[0042] Pre-curing: First, apply a layer of silicone oil to the mold to facilitate demolding later. Pour the vacuum-degassed mixture into the mold, first using a beaker to pour most of it in, then using a dropper to fill in the rest. After pouring into the mold, preheat the heating and pressurizing oven to 80°C. Place the mold inside and pressurize it to 7-10 bar, maintaining the temperature at 80°C for half an hour. After half an hour, the mixture will appear as a viscous white gel.

[0043] Primary curing: Then heat to 120°C and maintain at 7-10 bar for two hours. After heating, it will be in a molten rubber state. Remove it and observe the state of the raw insulating adhesive. Let it rest at room temperature, and then conduct the corresponding tests. Example 3

[0044] Example 3 of this invention provides a raw EPDM rubber and its preparation method, comprising the following steps: Raw material refining: 50 parts of high-purity ethylene, 50 parts of propylene, 5 parts of DCPD and 9 parts of n-hexane are subjected to deep dehydration and deoxygenation treatment.

[0045] Stirring: The treated ethylene, propylene, DCPD, and n-hexane are placed in a clean, dry beaker and mixed. One part dicumyl peroxide is added, and the mixture is first stirred briefly with a glass rod to achieve a uniform mixture. Then, two parts Ziegler-Natta catalyst and one part vinyltris(2-methoxyethoxy)silane are added to promote the polymerization reaction. Finally, the mixture is thoroughly stirred with a stirrer to achieve complete mixing.

[0046] Vacuum degassing: The mixed reagents are placed in a vacuum degassing machine for degassing, which takes 3-5 minutes. The mixture after degassing will have a very viscous consistency.

[0047] Pre-curing: First, apply a layer of silicone oil to the mold to facilitate demolding later. Pour the vacuum-degassed mixture into the mold, first using a beaker to pour most of it in, then using a dropper to fill in the rest. After pouring into the mold, preheat the heating and pressurizing oven to 80°C. Place the mold inside and pressurize it to 7-10 bar, maintaining the temperature at 80°C for half an hour. After half an hour, the mixture will appear as a viscous white gel.

[0048] Primary curing: Then heat to 120°C and maintain at 7-10 bar for two hours. After heating, it will be in a molten rubber state. Remove it and observe the state of the raw insulating adhesive. Let it rest at room temperature, and then conduct the corresponding tests.

[0049] The hardness (HA) of the EPDM raw rubber prepared in Examples 1-3 of this invention was tested according to test standard VDA675202, and the elongation at break (%) and tensile strength (MPa) of the EPDM raw rubber prepared in Examples 1-3 of this invention were tested according to test standard DIN 53504. The test results are shown in Table 1 below.

[0050] Table 1 Test performance Test Standards Standard value Example 1 Example 2 Example 3 Hardness (HA) VDA675202 55±5 59 56 57 Elongation at break (%) DIN 53504 >550 600 561 574 Tensile strength (MPa) DIN 53504 >20 25 22 23 As can be seen from Table 1 above, the hardness, elongation at break and tensile strength of the EPDM raw rubber prepared in the embodiments of the present invention all meet the standard requirements.

[0051] Currently, the import price of EPDM raw rubber is approximately RMB 26,800 per ton, while the domestic price is approximately RMB 25,000 per ton. In contrast, the price of the EPDM raw rubber prepared according to the embodiments of this invention is approximately RMB 5,146 per ton. Compared to the domestic price, the EPDM raw rubber product prepared according to the embodiments of this invention has a significant price advantage and can significantly reduce the production costs of enterprises that rely on EPDM raw rubber as a raw material.

[0052] The preparation method of EPDM raw rubber provided in this invention has a simple process flow. The raw materials are mixed, vacuum degassed, and cured under two steps of heating and pressure to produce EPDM raw rubber products that meet the standard requirements. This invention, by controlling the proportions of each component in the raw materials and using appropriate pre-curing and primary curing conditions, can efficiently and cost-effectively prepare EPDM raw rubber products.

[0053] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for preparing EPDM raw rubber, characterized in that, Includes the following steps: S1. Pre-treat ethylene, propylene, dicyclopentadiene and solvent by dehydration and deoxygenation; S2. Add sulfiding agent, catalyst, and activator to the pretreated raw material and mix well, then perform vacuum degassing treatment; S3. Pour the mixed material into the mold and pre-cur it under heating and pressure. S4. After the pre-curing, the main curing continues under heating and pressure.

2. The method for preparing EPDM raw rubber as described in claim 1, characterized in that, The raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 30-50 parts; Acrylic: 50-70 parts; Dicyclopentadiene: 2-8 parts; Vulcanizing agent: 1-5 parts; Catalyst: 2-5 parts; Activator: 1~1.5 parts Solvent: 6-9 parts.

3. The method for preparing EPDM raw rubber as described in claim 2, characterized in that, The vulcanizing agent is dicumyl peroxide, the catalyst is a Ziegler-Natta catalyst, the activator is vinyltris(2-methoxyethoxy)silane, and the solvent is n-hexane.

4. The method for preparing EPDM raw rubber as described in claim 3, characterized in that, The raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 40 parts; Acrylic: 60 parts; Dicyclopentadiene: 6 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

5. The method for preparing EPDM raw rubber as described in claim 3, characterized in that, The raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 30 parts; Acrylic: 70 parts; Dicyclopentadiene: 7 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

6. The method for preparing EPDM raw rubber as described in claim 3, characterized in that, The raw materials in the EPDM raw rubber are formulated in the following proportions by weight: Ethylene: 50 parts; Acrylic: 50 parts; Dicyclopentadiene: 5 parts; Vulcanizing agent: 1 part; Catalyst: 2 parts; Activator: 1 part Solvent: 9 parts.

7. A method for preparing EPDM raw rubber as described in claim 1, characterized in that, The pre-curing temperature is 80~100 ℃, the pressure is 7~10 bar, and the time is 30~40 min.

8. A method for preparing EPDM raw rubber as described in claim 1, characterized in that, The primary curing temperature is 110~120 ℃, the pressure is 7~10 bar, and the time is 120~130 min.

9. A method for preparing EPDM raw rubber as described in claim 1, characterized in that, The vacuum degassing process takes 3 to 5 minutes.

10. A type of EPDM raw rubber, characterized in that, It is obtained by the preparation method according to any one of claims 1-9.

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