EPDM foamed rubber for vehicles and preparation method and application thereof

Abstract

The invention discloses EPDM (Ethylene-Propylene-Diene Monomer) foamed rubber for vehicles as well as a preparation method and application thereof, and belongs to the technical field of foamed rubber.The EPDM foamed rubber for vehicles is prepared from the following raw materials in parts by weight: 90-110 parts of ethylene propylene diene monomer, 40-60 parts of carbon black, 40-60 parts of argil, 50-75 parts of paraffin oil, 5-10 parts of zinc oxide, 0.5-2.5 parts of stearic acid, 5-10 parts of azodicarbonamide, 1-5 parts of peroxide and 1-5 parts of N, N-dimethylformamide. The EPDM foamed rubber for the vehicle has the advantages that the performance of normal-temperature mechanics, compression resilience and the like is met, and the EPDM foamed rubber still has excellent resilience after being subjected to high temperature of 90 DEG C, can keep good sealing performance and has excellent high-temperature resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of foam rubber, and in particular relates to an EPDM foam rubber for vehicles, a preparation method and an application thereof. Background Art

[0002] EPDM is a common sealing material for automotive lamps. Currently, taillight sealing materials commonly use EPDM foam, including double-sided crusted closed-cell EPDM foam and non-crusted closed-cell EPDM foam. Compared to non-crusted EPDM foam, crusted foam offers superior impact resistance and resilience. When bonded to the lamp, it provides improved sealing and resistance to high-temperature deformation, but it also comes at a higher cost. Crusted foam is typically bonded to the lamp using adhesive tape. Due to the low surface energy of EPDM itself, a primer coating is required to improve the bonding between the housing and the tape. This not only poses significant risks to worker health and the environment, but also reduces production efficiency.

[0003] Therefore, from a cost and environmental perspective, non-crusting EPDM foam is preferred in actual use. However, seals made from this material have numerous drawbacks. Not only must product deformation be considered during lamp design, requiring a higher compression rating, but it also deforms more severely than crusting foam when exposed to high temperatures, easily leading to seal failure. Water seepage in rainy weather or during car washes can cause fogging and even leaks inside the lamp, potentially compromising driving safety.

[0004] Chinese patent CN106009320A discloses an EPDM polymer foam lamp seal material and its preparation method. The material is made from the following raw materials by weight: 30-60% EPDM rubber, 1-5% activator, 20-50% reinforcing agent, 14-47% softener, 1-5% vulcanizer, and 1-5% foaming agent. However, the patent does not address the material's airtightness after exposure to high temperatures. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an automotive EPDM foam rubber and its preparation method and application. While meeting the properties of room temperature mechanics, compression rebound, etc., the automotive EPDM foam rubber still has excellent rebound elasticity after being subjected to a high temperature of 90°C, can maintain good sealing, and has excellent high temperature resistance.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The invention provides an EPDM foam rubber for vehicles. The EPDM foam rubber for vehicles is composed of the following raw materials in parts by weight: 90-110 parts of ethylene propylene diene monomer rubber, 40-60 parts of carbon black, 40-60 parts of clay, 50-75 parts of paraffin oil, 5-10 parts of zinc oxide, 0.5-2.5 parts of stearic acid, 5-10 parts of azodicarbonamide, 1-5 parts of peroxide, and 0.1-1.0 part of N,N'-m-phenylene bismaleimide.

[0008] Furthermore, in one embodiment of the present invention, the automotive EPDM foam rubber is preferably composed of the following raw materials in parts by weight: 100 parts of ethylene propylene diene monomer rubber, 50 parts of carbon black, 50 parts of clay, 65 parts of paraffin oil, 6 parts of zinc oxide, 1.5 parts of stearic acid, 8 parts of azodicarbonamide, 2.8 parts of peroxide, and 0.45 parts of N,N'-m-phenylene bismaleimide.

[0009] In one embodiment of the present invention, the automotive EPDM foam rubber is preferably composed of the following raw materials in parts by weight: 90 parts of ethylene propylene diene monomer rubber, 40 parts of carbon black, 40 parts of clay, 50 parts of paraffin oil, 5 parts of zinc oxide, 2.0 parts of stearic acid, 5 parts of azodicarbonamide, 3.0 parts of peroxide, and 0.20 parts of N,N'-m-phenylene bismaleimide.

[0010] In one embodiment of the present invention, the automotive EPDM foam rubber is preferably composed of the following raw materials in parts by weight: 110 parts of ethylene propylene diene monomer rubber, 60 parts of carbon black, 60 parts of clay, 75 parts of paraffin oil, 8 parts of zinc oxide, 2.5 parts of stearic acid, 9 parts of azodicarbonamide, 3.5 parts of peroxide, and 0.8 parts of N,N'-m-phenylene bismaleimide.

[0011] The peroxide is dicumyl peroxide.

[0012] The present invention also provides a method for preparing the automotive EPDM foam rubber, which comprises the following steps:

[0013] (1) Mixing: Add carbon black, clay, zinc oxide, stearic acid and paraffin oil to EPDM rubber in sequence and mix them together. After mixing, take out the sheet and cool it down.

[0014] (2) The cooled sheet is placed in an internal mixer, and azodicarbonamide, peroxide, and N,N'-m-phenylene bismaleimide are added for internal mixing. After being taken out of the pot, the sheet is thinned in an open mixing mill to obtain a rubber sheet;

[0015] (3) Vulcanization: The rubber sheet is vulcanized and then sliced ​​and peeled after cooling.

[0016] In step (3), the vulcanization temperature is 170-180° C. and the time is 20-30 minutes.

[0017] In step (3), the cooling step refers to placing the vulcanized rubber in a room temperature environment for more than 24 hours. The rubber after cooling is easier to cut, and the sheet is less likely to deform significantly during cutting.

[0018] The present invention also provides application of the automotive EPDM foam rubber as a sealing material for automotive lamps.

[0019] The automotive EPDM foam rubber provided by the present invention uses ethylene propylene diene monomer (EPDM) as the main rubber, and uses carbon black and clay instead of kaolin, thereby improving the plasticity and reinforcement performance of the rubber and enhancing the hardness, tensile strength and elongation of the EPDM foam rubber. Meanwhile, the amount of paraffin oil is controlled within 50-75 parts, thereby improving the processability of the rubber and the elasticity and stretchability of the finished product. Stearic acid is used as a plasticizer and stabilizer, peroxide and N,N'-m-phenylene bismaleimide are used as vulcanizing agents, zinc oxide is used as a vulcanization activator, and azodicarbonamide is used as a foaming agent to prepare a vehicle-use EPDM foam rubber with a density of 0.12-0.19 g / cm 3 , automotive EPDM foam rubber with a hardness of 10-20SHC and a sealing compression of 45-65%, has excellent resilience and sealing properties when used at room temperature to 90°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The automotive EPDM foam rubber provided by the present invention has good high temperature resistance. When used as a lamp sealing gasket material, it can improve the sealing performance of the lamp sealing gasket under high temperature use, thereby overcoming the airtight failure problem caused by poor sealing of the sealing gasket. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the embodiments.

[0023] Example 1

[0024] Disclosed is an automotive EPDM foam rubber, which is composed of the following raw materials in parts by weight: 100 parts of EPDM rubber, 50 parts of carbon black, 50 parts of clay, 65 parts of paraffin oil, 6 parts of zinc oxide, 1.5 parts of stearic acid, 8 parts of azodicarbonamide, 2.8 parts of dicumyl peroxide, and 0.45 parts of N,N'-m-phenylene bismaleimide.

[0025] The preparation method of the automotive EPDM foam rubber is as follows:

[0026] (1) Mixing: Add carbon black, clay, zinc oxide, stearic acid and paraffin oil to the EPDM rubber in the formula and mix them in order. After mixing, take out the sheet and cool it down.

[0027] (2) The cooled sheet is placed in an internal mixer, and azodicarbonamide, diisopropylbenzene peroxide, and N,N'-m-phenylene bismaleimide are added for internal mixing. After being taken out of the pot, the sheet is thinned in an open mixer to obtain a rubber sheet;

[0028] (3) Vulcanization: The rubber sheet is transferred to the vulcanization workshop for vulcanization at 175°C for 25 minutes. After the vulcanized rubber sheet is placed at room temperature for 24 hours, it is sliced ​​and peeled.

[0029] Example 2

[0030] Disclosed is an automotive EPDM foam rubber, which is composed of the following raw materials in parts by weight: 90 parts of ethylene propylene diene monomer rubber, 40 parts of carbon black, 40 parts of clay, 50 parts of paraffin oil, 5 parts of zinc oxide, 2.0 parts of stearic acid, 5 parts of azodicarbonamide, 3.0 parts of dicumyl peroxide, and 0.20 parts of N,N'-m-phenylene bismaleimide.

[0031] The preparation method of the automotive EPDM foam rubber is as follows:

[0032] (1) Mixing: Add carbon black, clay, zinc oxide, stearic acid and paraffin oil to the EPDM rubber in the formula and mix them in order. After mixing, take out the sheet and cool it down.

[0033] (2) The cooled sheet is placed in an internal mixer, and azodicarbonamide, diisopropylbenzene peroxide, and N,N'-m-phenylene bismaleimide are added for internal mixing. After being taken out of the pot, the sheet is thinned in an open mixer to obtain a rubber sheet;

[0034] (3) Vulcanization: The rubber sheet is transferred to the vulcanization workshop for vulcanization at 170°C for 30 minutes. After the vulcanized rubber sheet is placed at room temperature for 24 hours, it is sliced ​​and peeled.

[0035] Example 3

[0036] Disclosed is an automotive EPDM foam rubber, which is composed of the following raw materials in parts by weight: 110 parts of ethylene propylene diene monomer rubber, 60 parts of carbon black, 60 parts of clay, 75 parts of paraffin oil, 8 parts of zinc oxide, 2.5 parts of stearic acid, 9 parts of azodicarbonamide, 3.5 parts of dicumyl peroxide, and 0.8 part of N,N'-m-phenylene bismaleimide.

[0037] The preparation method of the automotive EPDM foam rubber is as follows:

[0038] (1) Mixing: Add carbon black, clay, zinc oxide, stearic acid and paraffin oil to the EPDM rubber in the formula and mix them in order. After mixing, take out the sheet and cool it down.

[0039] (2) The cooled sheet is placed in an internal mixer, and azodicarbonamide, diisopropylbenzene peroxide, and N,N'-m-phenylene bismaleimide are added for internal mixing. After being taken out of the pot, the sheet is thinned in an open mixer to obtain a rubber sheet;

[0040] (3) Vulcanization: The rubber sheet is transferred to the vulcanization workshop for vulcanization at 180°C for 20 minutes. After the vulcanized rubber sheet is placed at room temperature for 24 hours, it is sliced ​​and peeled.

[0041] Comparative Example 1

[0042] Disclosed is an automotive EPDM foam rubber, which is composed of the following raw materials in parts by weight: 110 parts of ethylene propylene diene monomer rubber, 65 parts of carbon black, 65 parts of clay, 75 parts of paraffin oil, 8 parts of zinc oxide, 2.5 parts of stearic acid, 9 parts of azodicarbonamide, 3.5 parts of dicumyl peroxide, and 0.8 part of N,N'-m-phenylene bismaleimide.

[0043] The preparation method of the automotive EPDM foam rubber is the same as that of Example 3.

[0044] Comparative Example 2

[0045] The other steps are the same as those in Example 1, except that the paraffin oil in the raw material is omitted.

[0046] The properties of the automotive EPDM foam rubbers in the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0047] Table 1

[0048]

[0049] The sealing performance of the automotive EPDM foam rubber in the above-mentioned embodiments and comparative examples at room temperature and high temperature was tested. The test method is as follows: a sealing gasket prepared using the automotive EPDM foam rubber in each embodiment and comparative example was used on a car taillight of a certain OEM. The lamp was placed on a workpiece and placed 5 cm underwater. The air was inflated to 3 kPa for 30 seconds. The lamp was observed for water leakage. Water leakage was marked as NG, and no water leakage was marked as OK. The test results are shown in Table 2.

[0050] Table 2

[0051]

[0052]

[0053] From the above content, it can be seen that the automotive EPDM foam rubber provided by the present invention can meet the airtightness requirements of the entire vehicle lamp at room temperature and high temperature of 90°C.

[0054] In Comparative Example 1, since the amount of carbon black and clay used was too high, the rubber had a relatively high hardness, poor rebound ability at a high temperature of 90° C., and poor air tightness.

[0055] In Comparative Example 2, since paraffin oil is omitted from the raw materials of the rubber, the ductility of the rubber is poor. Even though the air tightness is good at room temperature, the air tightness becomes worse after being exposed to a high temperature of 90°C.

[0056] The above-mentioned detailed description of an automotive EPDM foam rubber, its preparation method and application with reference to the embodiments is illustrative rather than restrictive. Several embodiments can be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. An EPDM foam rubber for automobiles, characterized in that: The automotive EPDM foam rubber is composed of the following raw materials in parts by weight: 90-110 parts of ethylene propylene diene monomer rubber, 40-60 parts of carbon black, 40-60 parts of clay, 50-75 parts of paraffin oil, 5-10 parts of zinc oxide, 0.5-2.5 parts of stearic acid, 5-10 parts of azodicarbonamide, 1-5 parts of peroxide, and 0.1-1.0 part of N,N'-m-phenylene bismaleimide.

2. The automotive EPDM foam rubber according to claim 1, characterized in that: The automotive EPDM foam rubber is composed of the following raw materials in parts by weight: 100 parts of ethylene propylene diene monomer rubber, 50 parts of carbon black, 50 parts of clay, 65 parts of paraffin oil, 6 parts of zinc oxide, 1.5 parts of stearic acid, 8 parts of azodicarbonamide, 2.8 parts of peroxide, and 0.45 parts of N,N'-m-phenylene bismaleimide.

3. The automotive EPDM foam rubber according to claim 1, characterized in that: The automotive EPDM foam rubber is composed of the following raw materials in parts by weight: 90 parts of ethylene propylene diene monomer rubber, 40 parts of carbon black, 40 parts of clay, 50 parts of paraffin oil, 5 parts of zinc oxide, 2.0 parts of stearic acid, 5 parts of azodicarbonamide, 3.0 parts of peroxide, and 0.20 parts of N,N'-m-phenylene bismaleimide.

4. The automotive EPDM foam rubber according to claim 1, characterized in that: The automotive EPDM foam rubber is composed of the following raw materials in parts by weight: 110 parts of ethylene propylene diene monomer rubber, 60 parts of carbon black, 60 parts of clay, 75 parts of paraffin oil, 8 parts of zinc oxide, 2.5 parts of stearic acid, 9 parts of azodicarbonamide, 3.5 parts of peroxide, and 0.8 part of N,N'-m-phenylene bismaleimide.

5. The automotive EPDM foam rubber according to any one of claims 1 to 4, characterized in that: The peroxide is dicumyl peroxide.

6. The method for preparing the automotive EPDM foam rubber according to any one of claims 1 to 5, wherein: The preparation method comprises the following steps: (1) Mixing: Add carbon black, clay, zinc oxide, stearic acid and paraffin oil to EPDM rubber in sequence and mix them together. After mixing, take out the sheet and cool it down. (2) The cooled sheet is placed in an internal mixer, and azodicarbonamide, peroxide, and N,N'-m-phenylene bismaleimide are added for internal mixing. After being taken out of the pot, the sheet is thinned in an open mixing mill to obtain a rubber sheet; (3) Vulcanization: The rubber sheet is vulcanized and then sliced ​​and peeled after cooling.

7. The preparation method according to claim 6, characterized in that In step (3), the vulcanization temperature is 170-180° C. and the time is 20-30 minutes.

8. The preparation method according to claim 6, characterized in that In step (3), the cooling refers to placing the vulcanized rubber in a room temperature environment for more than 24 hours.

9. Use of the automotive EPDM foam rubber according to any one of claims 1 to 5 as a sealing material for automotive lamps.

Images