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KR-102962185-B1 - Rubber composition improved electric insulating property for reducing galvanic corrosion

KR102962185B1KR 102962185 B1KR102962185 B1KR 102962185B1KR-102962185-B1

Abstract

The present invention relates to a rubber composition for improving electrical insulation properties for galvanic corrosion improvement, a method for manufacturing the same, and a rubber hose for vehicles to which the same is applied, comprising a base polymer, a reinforcing agent, an anti-aging agent, an activator, a plasticizer, and a crosslinking agent, wherein the rubber composition has an electrical insulation resistance ( 10⁷ Ω·cm) of 50 or more.

Inventors

  • 박종민

Assignees

  • 현대자동차주식회사
  • 기아 주식회사

Dates

Publication Date
20260508
Application Date
20191211

Claims (18)

  1. In a rubber composition for preventing galvanic corrosion, It includes a base polymer, reinforcing agent, anti-aging agent, activator, plasticizer and crosslinking agent, The above base polymer includes a first EPDM rubber and a second EPDM rubber, and The first EPDM rubber above is an EPDM having a 5-ethylidene-2-norbornene (ENB) content of 8% to 10%, and The second EPDM rubber above is EPDM with an ethylene content of 70% to 75%, and The first EPDM rubber and the second EPDM rubber are included in a weight ratio of 30 to 50 : 50 to 70, and The above reinforcing agent includes carbon black and inorganic fillers, and With respect to 100 parts by weight of base polymer, the carbon black is 30 to 50 parts by weight and the inorganic filler is 25 to 45 parts by weight, and The above carbon black has a DBP (ml/100g) of 40 to 150 and an I2 (mg/g) of 10 to 50, and The above inorganic filler is silica, and The above silica has a BET ( m² /g) of 180 to 230 and a density (g/l) of 120 to 160, and The above plasticizer is included in an amount of 1.5 to 3.5 parts by weight per 100 parts by weight of the base polymer, and A rubber composition in which the above plasticizer is a paraffinic oil.
  2. In Article 1, The above rubber composition is a rubber composition having an electrical insulation resistance ( 10⁷ Ω·cm) of 50 or more.
  3. In Article 1, The above anti-aging agent is included in an amount of 0.5 to 1.5 parts by weight per 100 parts by weight of the base polymer, and A rubber composition in which the above-mentioned anti-aging agent is N'-isopropyl-N-phenyl--phenylenediamine.
  4. In Article 1, The above activator is included in an amount of 1.5 to 6 parts by weight per 100 parts by weight of the base polymer, and A rubber composition in which the above-mentioned activator is one or more of zinc oxide and stearic acid.
  5. In Article 4, The above activator includes zinc oxide and stearic acid, and The above zinc oxide is 2 to 4 parts by weight per 100 parts by weight of base polymer, A rubber composition comprising 0.5 to 1.5 parts by weight of the above stearic acid per 100 parts by weight of base polymer.
  6. In Article 1, A rubber composition comprising 0.5 to 3.5 parts by weight of the crosslinking agent per 100 parts by weight of base polymer.
  7. In Article 6, The above crosslinking agent is yellow phosphorus, a rubber composition.
  8. A rubber hose for a vehicle comprising a rubber composition of any one of claims 1 to 7.
  9. In a method for manufacturing a rubber composition according to any one of claims 1 to 7, A step of mixing a reinforcing agent, an anti-aging agent, an activator, and a plasticizer into a base polymer; and The method includes the step of mixing a crosslinking agent into the mixed polymer; The above base polymer includes a first EPDM rubber and a second EPDM rubber, and The first EPDM rubber above is an EPDM having a 5-ethylidene-2-norbornene (ENB) content of 8% to 10%, and The second EPDM rubber above is EPDM with an ethylene content of 70% to 75%, and The first EPDM rubber and the second EPDM rubber are included in a weight ratio of 30 to 50 : 50 to 70, and The above reinforcing agent includes carbon black and inorganic fillers, and With respect to 100 parts by weight of base polymer, the carbon black is 30 to 50 parts by weight and the inorganic filler is 25 to 45 parts by weight, and The above carbon black has a DBP (ml/100g) of 40 to 150 and an I2 (mg/g) of 10 to 50, and The above inorganic filler is silica, and The above silica has a BET ( m² /g) of 180 to 230 and a density (g/l) of 120 to 160, and The above plasticizer is included in an amount of 1.5 to 3.5 parts by weight per 100 parts by weight of the base polymer, and A method for manufacturing a rubber composition in which the above plasticizer is a paraffinic oil.
  10. In Article 9, The above anti-aging agent is included in an amount of 0.5 to 1.5 parts by weight per 100 parts by weight of the base polymer, and A method for manufacturing a rubber composition, wherein the above-mentioned activator is included in an amount of 1.5 to 6 parts by weight per 100 parts by weight of base polymer.
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Description

Rubber composition with improved electric insulating property for reducing galvanic corrosion The present invention relates to a rubber composition for improving electrical insulation properties to improve galvanic corrosion, a method for manufacturing the same, and a rubber hose for vehicles to which the same is applied. Currently, automobiles widely use rubber hoses to deliver various fluids to cooling systems, fuel systems, braking systems, and more. It is common practice to use metal clamps to secure hoses within the system. However, there is a corrosion problem caused by galvanic corrosion due to the potential difference between metal and rubber materials, which can lead to reduced marketability and performance degradation due to hose detachment. Attached Fig. 1 is a photograph of rust formation on a durability development vehicle, and Attached Fig. 2 is a field rust formation on a mass-produced vehicle. Galvanic corrosion occurs when two different metals come into contact within an electrolyte, generating a potential difference that causes an electric current to flow between them. As a result, the corrosion of the highly corrosion-resistant metal (cathode) is inhibited, while the corrosion of the highly active metal (anode) is accelerated; this type of corrosion is called galvanic corrosion. To address this, the problem is currently being resolved by galvanizing the clamps. However, adding an additional plating layer to improve corrosion resistance not only increases manufacturing costs but is also insufficient to solve the issue due to plating cracking caused by tools during clamp assembly. Therefore, there is a need for technology to solve the aforementioned problems. Figure 1 is a photograph of the rust phenomenon on a durable development vehicle. Figure 2 shows the field rust phenomenon of a mass-produced vehicle. Figure 3 shows the results of the component and physical property evaluation of Examples 1-7 and Comparative Examples 1-7 of the present invention. Figure 4 is the experimental result according to Experimental Example 3 of the present invention. Descriptions of known components and functions are omitted if it is determined that they may obscure the essence of the invention. In this specification, the term "comprising" means that other components may be additionally included unless otherwise specifically stated. In this specification, where a range is described for a variable, it will be understood that the variable includes all values within the described range, including the described endpoints of the range. For example, the range “5 to 10” will be understood to include not only the values 5, 6, 7, 8, 9, and 10, but also any sub-ranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., and any values between integers valid for the category of the described range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, and 6.5 to 9. Also, for example, the range “10% to 30%” will be understood to include all integers including values such as 10%, 11%, 12%, 13%, etc. and up to 30%, as well as any sub-range such as 10% to 15%, 12% to 18%, 20% to 30%, etc., and any value between valid integers within the stated range category such as 10.5%, 15.5%, 25.5%, etc. The present invention will be described in detail below. The present invention relates to a rubber compound composition that dramatically improves the electrical insulation resistance of a rubber material for hoses by approximately 100 times in order to improve galvanic corrosion caused by the potential difference between a rubber hose and a clamp. In general materials, simply increasing the amount of inorganic filler to increase electrical resistance results in increased electrical resistance, but product molding is not performed properly (squashing or shape change during hose extrusion) or physical properties are significantly degraded, making it impossible to satisfy the durability performance required for hoses, such as burst pressure and negative pressure resistance. To overcome this, the type and amount of base polymer and the content of plasticizer (paraffin-based oil) are optimized to overcome the above problems and significantly improve durability and corrosion resistance within the clamp. According to the rubber composition of the present invention, the condition and aging properties are maintained at a level equivalent to existing automotive rubber hoses, while simultaneously significantly improving electrical insulation resistance, and this improvement has been confirmed through material, product, and system durability. Various aspects of the present invention will be described below. One aspect of the present invention provides a rubber composition for preventing galvanic corrosion, comprising a base polymer, a reinforcing agent, an anti-aging agent, an activator, a plasticizer, and a crosslinking agent, wherein the base polymer comprises a first EPDM rubber and a second EPDM rubber, wherein the first EPDM rubber is an EPDM having a 5-ethylidene-2