Method for improving performance of ethylene propylene diene monomer by using polypropylene doping species
By mixing and modifying polypropylene with different molecular chain structures into EPDM rubber, the problem of degradation of traditional EPDM rubber at high temperatures is solved, and the comprehensive performance of the material is significantly improved. It is suitable for wind power torsion cable applications at high voltage and high temperatures.
Patent Information
- Application Number
- CN202411885772.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-04-15
AI Technical Summary
The mechanical and dielectric properties of traditional ethylene propylene rubber will be greatly reduced at high temperatures, limiting the development of wind power equipment in higher voltage levels and larger capacity.
By doping polypropylene with different molecular chain structures into ethylene propylene ternary rubber, including isotropic homopolymer polypropylene, random copolymer polypropylene and block copolymer polypropylene, the comprehensive performance of the material is improved.
The crystallinity of EPDM rubber and multiple key performance indicators are significantly improved, including breakage field strength, tensile strength, elongation of break, elastic modulus and thermal conductivity, to meet the high-performance needs of wind power torsion cables.
Smart Images
Figure CN119823496A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of EPDM rubber, and in particular to a method for improving the performance of EPDM rubber by utilizing polypropylene doping species. Background Art
[0002] Torsion cables are key power transmission components that connect motors and towers in wind turbines. They need to withstand the combined effects of mechanical stress, electrical loads, and high temperature environments. Ethylene propylene diene monomer (EPDM), a polymer elastomer copolymerized from ethylene, propylene, and non-conjugated dienes, is currently the preferred material for the insulation layer of wind power torsion cables. With its outstanding heat resistance, aging resistance, corrosion resistance, and excellent electrical insulation and corona resistance, it is widely used in many fields such as transformer insulation pads, insulating sheaths, and special cables. However, the elastic modulus and strength of EPDM are relatively low, so in practical applications, inorganic fillers are often added to enhance its mechanical properties, and vulcanization reactions are used to promote cross-linking between molecular chains to build a stable three-dimensional network structure, thereby improving its physical properties.
[0003] EPDM rubber products can meet the torsion resistance requirements of torsion cables due to their excellent elasticity and flexibility. At the same time, their unique phase structure gives the material excellent cold resistance and salt spray resistance, allowing it to maintain stable performance in high altitude and marine environments with severe salt spray corrosion, meeting the use requirements under extreme conditions. Traditional EPDM modification methods mostly use blending with low-density polyethylene, but this method will cause the mechanical and dielectric properties of EPDM to drop significantly due to the melting of ethylene segments at high temperatures, thereby limiting the development of wind power equipment at higher voltage levels and larger capacities.
[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention
[0005] The invention provides a method for improving the performance of EPDM rubber by utilizing polypropylene doping species, and the comprehensive performance of the material can be effectively improved by blending polypropylene with EPDM.
[0006] The method for preparing EPDM rubber doped with polypropylene comprises: Step 1: adding polypropylene to the EPDM base material, wherein the polypropylene includes at least one of isotactic homopolypropylene, random copolymer polypropylene and block copolymer polypropylene; Step 2: Blending and modification are performed by a torque rheometer to uniformly mix the doped EPDM rubber base material with polypropylene, lead oxide, paraffin, antioxidant, dicumyl peroxide and nano zinc oxide; Step 3: Press the uniformly mixed rubber into sheets and cut them into samples of predetermined sizes.
[0007] In the method for preparing EPDM rubber doped with polypropylene, the doping amount of the polypropylene is 5% of the total weight of the EPDM rubber.
[0008] In the method for preparing EPDM rubber doped with polypropylene, the blending modification includes: Carry out equipment cleaning in the torque rheometer; After cleaning, add EPDM base material and heat until evenly heated; Add polypropylene, lead oxide, paraffin and antioxidant in sequence, increase the speed and mix evenly; After lowering the temperature, add dicumyl peroxide and nano zinc oxide, continue mixing, and mix thoroughly.
[0009] In the method for preparing EPDM rubber doped with polypropylene, the pressing into sheets comprises: Use a flat vulcanizing press to press the uniformly mixed rubber into sheets; The samples were weighed according to the mold volume and fixed using steel plates and polyester film; Preheat and pressurize at 120°C, and perform cross-linking reaction at 180°C; After the cross-linking reaction is completed, continue to pressurize and cool to room temperature; Cut the specimens into predetermined sizes.
[0010] In the method for preparing EPDM rubber doped with polypropylene, when the doped polypropylene is isotactic homopolymer polypropylene, the obtained EPDM rubber has a breakdown field strength of at least 43.91 kV / mm at 25°C, a breakdown field strength retention rate of at least 88% at 90°C, a tensile strength of at least 12.72 MPa at 25°C, at least 2.82 MPa at 90°C, an elongation at break at room temperature of at least 633.95%, an elastic modulus of about 8.33 MPa, and exhibits the highest thermal conductivity in the range of 25-90°C.
[0011] In the method for preparing EPDM rubber doped with polypropylene, the weight parts of the raw materials of the various components of the EPDM rubber are: 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide, and 1.5 parts of antioxidant.
[0012] In the method for preparing EPDM rubber doped with polypropylene, isotactic homopolypropylene is doped into the EPDM rubber base material, and the isotactic homopolypropylene accounts for 5% of the total weight of the EPDM rubber.
[0013] In the method for preparing EPDM rubber doped with polypropylene, the polypropylene has different molecular chain structures.
[0014] An EPDM rubber is prepared by the method for preparing the EPDM rubber doped with polypropylene.
[0015] The EPDM rubber is used in the field of cable insulation materials for wind power torsion.
[0016] Compared with the prior art, the present invention has the following advantages: the present invention has deeply explored the significant improvement effect on material properties by precisely adding polypropylene with different molecular chain structures, including isotactic polypropylene, block polypropylene and random polypropylene, to EPDM rubber. The research results show that the addition of isotactic polypropylene not only significantly improves the crystallinity of EPDM rubber, but also achieves significant improvements in multiple key performance indicators.
[0017] Specifically, EPDM modified with isotactic polypropylene has excellent electrical properties, with a breakdown field strength of up to 43.91 kV / mm at 25°C, and can maintain 88% of the breakdown field strength (38.633 kV / mm) even at a high temperature of 90°C. At the same time, the resistivity is stable, showing excellent temperature stability. In terms of mechanical properties, the material has a tensile strength of 12.72 MPa at 25°C and can still maintain 2.82 MPa at 90°C. The elongation at break at room temperature is as high as 633.95%, and the elastic modulus is 8.33 MPa, which fully meets the use standards of torsion cables. In addition, EPDM modified with isotactic polypropylene exhibits the highest thermal conductivity in the range of 25-90°C, further improving its thermal properties.
[0018] Structural analysis revealed that the corresponding crystallinity of the blended rubbers doped with random polypropylene, block polypropylene and isotactic polypropylene were 0.95%, 1.75% and 2.2%, respectively. This shows that doping with isotactic polypropylene significantly improves the regularity and crystallization ability of the EPDM molecular chain, and plays the role of a physical crosslinking point in the blending system, significantly enhancing the interaction between the molecular chains, thereby greatly improving the electrical, mechanical and thermal properties of the EPDM rubber. The present invention utilizes isotactic polypropylene due to its unique molecular chain configuration, and shows significant advantages in the modification of EPDM rubber. This discovery not only provides new ideas for the research and development of high-performance rubber materials, but also provides a new material with broad application prospects in the field of wind power torsion cable insulation materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.
[0020] In the attached picture: Figure 1 Schematic diagram of the density test results of different types of EPDM rubbers in the present invention, wherein the polypropylene structure does not affect the density and crosslinking density of EPDM rubber: the density is 1.4±0.01 g / cm 3 within the scope; Figure 2 Schematic diagram of the test results of crosslinking density of different types of EPDM rubbers in the present invention, wherein the polypropylene structure does not affect the crosslinking density of EPDM rubber: the crosslinking density is (2.4±0.1)×10 -4 mol / cm 3 within the scope; Figure 3 Schematic diagram of the surface morphology of different types of EPDM rubbers of the present invention, Figure 3 (a) Schematic diagram of the surface morphology of random PP blend rubber. Figure 3 (b) Schematic diagram of the surface morphology of block PP blend rubber. Figure 3 (c) Schematic diagram of the surface morphology of isotactic PP blended rubber, in which the polypropylene structure does not affect its dispersibility in EPDM rubber: no inorganic filler agglomeration phenomenon is observed in the three blended rubbers except for nano zinc oxide; Figure 4 Schematic diagram of DSC test results of different types of EPDM rubbers of the present invention, isotactic polypropylene blended rubber has the highest crystallinity: calculated by using the melting peak of the heat flow curve, isotactic polypropylene blended rubber has the highest crystallinity (2.2%); Figure 5 Schematic diagram of AC breakdown test results of different types of EPDM rubbers of the present invention, wherein at each temperature, the isotactic polypropylene blended rubber exhibits higher breakdown field strength and better temperature stability, effectively improving the insulation performance of the material at high temperatures; Figure 6Schematic diagram of dielectric properties of different types of EPDM rubbers of the present invention, wherein the molecular chain structure of polypropylene has little effect on dielectric constant and loss: as the temperature increases, the dielectric constants of the three blended rubbers first decrease and then increase, while the dielectric loss tangent value continues to increase; at low temperatures (between -50°C and 50°C), the dielectric constant and loss of the isotactic polypropylene blended rubber are slightly higher, and are basically the same above 70°C; Figure 7 A schematic diagram comparing the tensile strengths of different types of EPDM rubbers of the present invention, wherein, compared with block polypropylene blended rubber and random polypropylene blended rubber, isotactic polypropylene blended EPDM rubber has higher tensile strength and performs well under high temperature conditions; Figure 8 The elongation at break of different types of EPDM rubbers of the present invention is compared, wherein the elongation at break of isotactic polypropylene blended EPDM rubber is slightly lower than that of block polypropylene blended rubber and random polypropylene blended rubber, but is still significantly higher than the minimum standard; Fig. 9 A schematic diagram showing the comparison of elastic moduli of different types of EPDM rubbers of the present invention, wherein the isotactic polypropylene blended EPDM rubber has a higher elastic modulus at room temperature than the block polypropylene blended rubber and the random polypropylene blended rubber, and the three blending systems all perform generally at high temperatures; Fig.10 Schematic diagram of thermal conductivity of different types of EPDM rubbers of the present invention, wherein the isotactic polypropylene blended rubber has higher thermal conductivity: the thermal conductivity of isotactic copolymerized polypropylene blended rubber at room temperature and high temperature is high; the thermal conductivity of the three materials decreases with increasing temperature, and the thermal conductivity of the isotactic polypropylene blended rubber is 0.174 W / (m*K) at 90°C.
[0021] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION
[0022] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0023] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.
[0024] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.
[0025] like Figures 1 to 10 As shown, the method for preparing EPDM rubber doped with polypropylene comprises the following steps: Step 1: adding polypropylene to the EPDM base material, wherein the polypropylene includes at least one of isotactic homopolypropylene, random copolymer polypropylene and block copolymer polypropylene; Step 2: Blending and modification are performed by a torque rheometer to uniformly mix the doped EPDM rubber base material with polypropylene, lead oxide, paraffin, antioxidant, dicumyl peroxide and nano zinc oxide; Step 3: Press the uniformly mixed rubber into sheets and cut them into samples of predetermined sizes.
[0026] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the doping amount of the polypropylene is 5% of the total weight of the EPDM rubber.
[0027] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the blending modification comprises: Carry out equipment cleaning in the torque rheometer; After cleaning, add EPDM base material and heat until evenly heated; Add polypropylene, lead oxide, paraffin and antioxidant in sequence, increase the speed and mix evenly; After lowering the temperature, add dicumyl peroxide and nano zinc oxide, continue mixing, and mix thoroughly.
[0028] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the pressing into sheets comprises: Use a flat vulcanizing press to press the uniformly mixed rubber into sheets; The samples were weighed according to the mold volume and fixed using steel plates and polyester film; Preheat and pressurize at 120°C, and perform cross-linking reaction at 180°C; After the cross-linking reaction is completed, continue to pressurize and cool to room temperature; Cut the specimens into predetermined sizes.
[0029] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, when the doped polypropylene is isotactic homopolypropylene, the obtained EPDM rubber has a breakdown field strength of at least 43.91 kV / mm at 25°C, a breakdown field strength retention rate of at least 88% at 90°C, a tensile strength of at least 12.72 MPa at 25°C, at least 2.82 MPa at 90°C, an elongation at break at room temperature of at least 633.95%, an elastic modulus of about 8.33 MPa, and exhibits the highest thermal conductivity in the range of 25-90°C.
[0030] In the preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the weight parts of the raw materials of the various components of the EPDM rubber are: 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide, and 1.5 parts of antioxidant.
[0031] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the EPDM rubber base material is doped with isotactic homopolypropylene, and the isotactic homopolypropylene accounts for 5% of the total weight of the EPDM rubber.
[0032] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, isotactic homopolypropylene, random copolymer polypropylene and block copolymer polypropylene are doped into the EPDM rubber base material, and the doping amounts of the isotactic homopolypropylene, random copolymer polypropylene and block copolymer polypropylene are all 5% of the total weight of the EPDM rubber.
[0033] In a preferred embodiment of the method for preparing EPDM rubber doped with polypropylene, the polypropylene has different molecular chain structures.
[0034] An EPDM rubber is prepared by the method for preparing the EPDM rubber doped with polypropylene.
[0035] The EPDM rubber is used in the field of cable insulation materials for wind power torsion. Example
[0036] Formula determination: weigh 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of random polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide and 1.5 parts of antioxidant according to the ratio, and package them separately.
[0037] Blending: In a torque rheometer, after cleaning at 170°C and 10r / min, add the EPDM base material weighed from the above formula, add random polypropylene, lead oxide, paraffin, and antioxidant after heating, increase the speed to 30r / min and mix for 15 minutes. After cooling to 90°C, add dicumyl peroxide and nano zinc oxide, and mix for 10 minutes to obtain a block sample.
[0038] Sample preparation: Use a flat vulcanizer to fix the blended sample between a steel plate and a polyester film, preheat at 120°C for 5 minutes and pressurize at 20 MPa to flatten, then crosslink at 180°C for 5 minutes (with 5 cycles of degassing), continue pressurizing for 5 minutes and then cool to room temperature to obtain a 10 cm × 10 cm × 0.5 mm square sample.
[0039] Example 2
[0040] Formula determination: weigh 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of block polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide and 1.5 parts of antioxidant according to the ratio, and package them separately.
[0041] Blending: In a torque rheometer, after cleaning at 170°C and 10r / min, add the EPDM base material weighed from the above formula, add block polypropylene, lead oxide, paraffin, and antioxidant after heating, increase the speed to 30r / min and mix for 15 minutes. After cooling to 90°C, add dicumyl peroxide and nano zinc oxide, and mix for 10 minutes to obtain a block sample.
[0042] Sample preparation: Use a flat vulcanizer to fix the blended sample between a steel plate and a polyester film, preheat at 120°C for 5 minutes and pressurize at 20 MPa to flatten, then crosslink at 180°C for 5 minutes (with 5 cycles of degassing), continue pressurizing for 5 minutes and then cool to room temperature to obtain a 10 cm × 10 cm × 0.5 mm square sample.
[0043] Example 3
[0044] Formula determination: weigh 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of isotactic polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide and 1.5 parts of antioxidant according to the ratio, and package them separately.
[0045] Blending: In a torque rheometer, after cleaning at 170°C and 10r / min, add the EPDM base material weighed from the above formula, add isotactic polypropylene, lead oxide, paraffin, and antioxidant after heating, increase the speed to 30r / min and mix for 15 minutes. After cooling to 90°C, add dicumyl peroxide and nano zinc oxide, and mix for 10 minutes to obtain a block sample.
[0046] Sample preparation: Use a flat vulcanizer to fix the blended sample between a steel plate and a polyester film, preheat at 120°C for 5 minutes and pressurize at 20 MPa to flatten, then crosslink at 180°C for 5 minutes (with 5 cycles of degassing), continue pressurizing for 5 minutes and then cool to room temperature to obtain a 10 cm × 10 cm × 0.5 mm square sample.
[0047] In Example 1, Example 2 and Example 3, random polypropylene, block polypropylene and isotactic polypropylene were used to modify EPDM rubber respectively, and the same preparation process was followed. After system performance testing and comparative analysis, it was confirmed that the isotactic polypropylene modified EPDM rubber in Example 3 exhibited the best comprehensive performance. Specifically, the introduction of isotactic polypropylene significantly improved the crystallinity of EPDM, thereby achieving significant improvements in multiple key performance indicators. In terms of electrical properties, the modified EPDM has a breakdown field strength of up to 43.91 kV / mm at 25°C, and can still maintain 38.633 kV / mm at 90°C (i.e., retaining 88% of the breakdown field strength), and the resistivity is stable, showing excellent temperature stability, and is suitable for applications with high voltage and large temperature changes. In terms of mechanical properties, the material has a tensile strength of 12.72MPa at 25°C and 2.82MPa at 90°C, a room temperature elongation of 633.95%, and an elastic modulus of 8.33MPa, fully meeting the application requirements of torsion cables. In addition, in terms of thermal properties, isotactic polypropylene modified EPDM exhibits the highest thermal conductivity in the range of 25-90°C, further enhancing its thermal stability.
[0048] The invention utilizes the high insulation performance, high temperature resistance grade and long-term high temperature resistance of polypropylene materials, combines the high compatibility and good interface adhesion of polypropylene materials with ethylene-propylene rubber, and significantly enhances the performance of rubber compounds through a blending process to obtain an ethylene-propylene rubber composite material with high temperature resistance and high voltage characteristics. The process steps of the method are concise and clear, the operation is simple, and the method has good repeatability, and can generally enhance the various properties of EPDM rubber.
[0049] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.
Claims
1. A method for preparing EPDM rubber doped with polypropylene, characterized in that: The method comprises the following steps: Step 1: adding polypropylene to the EPDM base material, wherein the polypropylene includes at least one of isotactic homopolypropylene, random copolymer polypropylene and block copolymer polypropylene; Step 2: Blending and modification are performed by a torque rheometer to uniformly mix the doped EPDM rubber base material with polypropylene, kaolin, lead oxide, paraffin, antioxidant, dicumyl peroxide and nano zinc oxide; Step 3: Press the uniformly mixed rubber into sheets and cut them into samples of predetermined sizes.
2. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: Preferably, the doping amount of the polypropylene is 5% of the total weight of the EPDM rubber.
3. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: The blending modification includes: Carry out equipment cleaning in the torque rheometer; After cleaning, add EPDM base material and heat until evenly heated; Add polypropylene, lead oxide, paraffin and antioxidant in sequence, increase the speed and mix evenly; After lowering the temperature, add dicumyl peroxide and nano zinc oxide, continue mixing, and mix thoroughly.
4. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: The tabletting comprises: Use a flat vulcanizing press to press the uniformly mixed rubber into sheets; The samples were weighed according to the mold volume and fixed using steel plates and polyester film; Preheat and pressurize at 120°C, and perform cross-linking reaction at 180°C; After the cross-linking reaction is completed, continue to pressurize and cool to room temperature; Cut the specimens into predetermined sizes.
5. The method for preparing EPDM rubber doped with polypropylene according to any one of claims 1 to 4, characterized in that: When the doped polypropylene is isotactic homopolymer polypropylene, the resulting EPDM rubber has a breakdown field strength of at least 43.91 kV / mm at 25°C, a breakdown field strength retention rate of at least 88% at 90°C, a tensile strength of at least 12.72 MPa at 25°C, at least 2.82 MPa at 90°C, an elongation at break at room temperature of at least 633.95%, an elastic modulus of about 8.33 MPa, and exhibits the highest thermal conductivity in the range of 25-90°C.
6. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: The weight parts of the raw materials of each component of EPDM rubber are: 95 parts of EPDM base material, 60 parts of kaolin, 5 parts of lead oxide, 5 parts of paraffin, 5 parts of polypropylene, 3 parts of dicumyl peroxide, 5 parts of nano zinc oxide, and 1.5 parts of antioxidant.
7. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: The EPDM rubber base material is doped with isotactic homopolypropylene, and the isotactic homopolypropylene accounts for 5% of the total weight of the EPDM rubber.
8. The method for preparing EPDM rubber doped with polypropylene as claimed in claim 1, characterized in that: The polypropylene has different molecular chain structures.
9. An EPDM rubber, characterized in that: The rubber is prepared by the method for preparing EPDM rubber doped with polypropylene as described in any one of claims 1 to 8.
10. The EPDM rubber according to claim 9, characterized in that It is used in the field of cable insulation materials for wind power torsion.