KR20120041069A - Rubber composition and dynamic damper comprising the same - Google Patents

Abstract

PURPOSE: A rubber composition is provided to be used at high-temperature area in engine, in case of using as a dynamic damper of vehicles, and to maintain initial ride comfort regardless of season or temperature. CONSTITUTION: A rubber composition comprises 100-150 parts by weight of ethylene-propylene rubber, 10-30 parts by weight of paraffin oil, 20-50 parts by weight of inorganic filler, 1-10 parts by weight of peroxide cross linker, 1-10 parts by weight of crosslinking promoter, and 1-10 parts by weight of antiaging agent. The weight average molecular weight of the ethylene-propylene rubber is 260,000-270,000, Mooney viscosity is 20-30, and ethylene content is 40-60 weight%. The inorganic filler is one or more kinds selected from calcium carbonate, talcum, clay, silica, mica, titanium dioxide, carbon black, graphite, woolastonite, and nanosilver.

Description

Rubber Composition and Dynamic Damper Comprising the Same

The present invention relates to a rubber composition and a dynamic damper comprising the same.

Automotive dynamic dampers are components that can effectively absorb vibration at low cost. The principle is to absorb the generated vibration by attaching a dynamic damper designed to have the same natural frequency as the vibration, and the higher the loss factor of the material, the better the absorption of vibration. Therefore, in any environmental condition, the original natural frequency is maintained, the loss factor is high, and the aging performance is improved, and the research for securing the long-term vibration insulation performance has been conducted.

As a material of the dynamic damper, it was common to use a rubber material having excellent vibration insulation performance. However, due to the characteristics of the rubber material, it hardens at low temperatures and the natural frequency rises, and there is a problem in that the natural frequency is released to lower the natural frequency. In addition, due to the high performance of the automobile and the integration of the engine room, the engine room atmosphere temperature is increased, thereby promoting aging of the nearby damper material, and the aged damper material has a problem that the function of vibration absorption is weakened due to the increase in natural frequency.

To solve this problem, natural rubber + styrene-butadiene rubber (SBR), natural rubber + butyl rubber have been developed from existing materials (natural rubber) for the purpose of securing heat resistance and increasing vibration insulation. In case of natural rubber + butyl rubber, the loss coefficient is high, but the natural frequency rise rate is too high at low temperature (-20 ℃), and the vibration insulation performance as a damper is lost. .

Accordingly, the present inventors have studied rubber compositions optimized for dynamic dampers for automobiles, and have developed a rubber composition having excellent heat resistance and excellent natural frequency change rate at low temperatures, and completing the present invention.

The present invention to solve the above problems 100 to 150 parts by weight of ethylene-propylene (EPDM) rubber; 10 to 30 parts by weight of paraffin oil; 20 to 50 parts by weight of the inorganic filler; 1 to 10 parts by weight of the peroxide crosslinking agent; 1 to 10 parts by weight of crosslinking accelerator; And it provides a rubber composition comprising 1 to 10 parts by weight of the antioxidant.

The present invention also provides a dynamic damper comprising the rubber composition.

By specifying the composition and composition ratio of the rubber composition according to the present invention, a rubber composition having excellent heat resistance and excellent natural frequency change rate at low temperature is provided. Therefore, when the rubber composition is used as a dynamic damper of an automobile, the rubber composition can be used even in a place where the temperature of the engine is high, and the initial riding comfort can be maintained regardless of the season or temperature.

Hereinafter, the present invention will be described in more detail.

The present invention is 100 to 150 parts by weight of ethylene-propylene (EPDM) rubber; 10 to 30 parts by weight of paraffin oil; 20 to 50 parts by weight of the inorganic filler; 1 to 10 parts by weight of the peroxide crosslinking agent; 1 to 10 parts by weight of crosslinking accelerator; And it relates to a rubber composition comprising 1 to 10 parts by weight of the antioxidant.

The ethylene-propylene (EPDM) rubber may have a weight average molecular weight of 260,000 to 270,000, a pattern viscosity of 20 to 30, and an ethylene-propylene rubber having an ethylene content of 40 to 60% by weight. When the ethylene-propene rubber is used, low temperature flexibility is improved and crystallinity is lowered, thereby improving workability and low temperature characteristics.

The inorganic filler is preferably at least one filler selected from the group consisting of calcium carbonate, talc, clay, silica, mica, titanium dioxide, carbon black, graphite, ulastonite, and nanosilver, more preferably carbon You can choose black.

The paraffin oil and the inorganic filler to be blended with the ethylene-propylene rubber are preferably blended in the above range by weight. Generally, paraffin oil is blended in an amount of 50 to 70 parts by weight based on 100 to 150 parts by weight of ethylene-propylene rubber, but in the present invention, it is minimized to 10 to 30 parts by weight, which is to maximize the amount of ethylene-propylene rubber. When formulated in the above range, the hardness is about 40 ~ 60 on the Shore A basis.

In the present invention, the crosslinking agent used a peroxide crosslinking agent as described above. Compared with sulfur crosslinking agents generally used in the prior art, there is an advantage of excellent heat resistance. Examples of the peroxide crosslinking agent include dicumyl peroxide, 1,1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane, di- (t-butylperoxyisopropyl) benzene, butyl-4, 4-bis (tert-butyldioxy) valerate, di- (2,4-dichlorobenzoyl) -peroxide, di- (2,4-dichlorobenzoyl) -peroxide, dibenzoyl peroxide, t-butyl peroxide Oxybenzoate, t-butylcumylperoxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane, di-t-butylperoxide, and 2,5-dimethyl-2, One or more selected from the group consisting of 5-di (t-butylperoxy) hexim-3 can be used, Preferably di (t-butylperoxyisopropyl) benzene can be used.

The crosslinking promoter is selected from the group consisting of triarylcyanurate (TAC), triarylisocyanurate (TAIC), trimethylolpropane trimethacrylate (TPTM), ethylene dimethacrylate (EDMA) and sulfur It may be one or more compounds.

The anti-aging agent inhibits and delays oxidation, and may use one or more compounds selected from the group consisting of amines, quinolines, phenols, imidazoles, and the like. Preferably, dihydroquinoline, N-phenyl-N'-isopropyl-p-phenylenediamine, or a mixture thereof can be used.

The present invention also relates to a dynamic damper comprising the rubber composition.

Hereinafter, the present invention will be described in detail with reference to specific examples, but the scope of the present invention is not limited to these examples.

Example , Comparative example  1 to 2

Using a rubber composition of the formulation as shown in Table 1 was prepared a material and a prototype for the dynamic damper. Comparative Example 1 is a rubber composition using natural rubber alone, and Comparative Example 2 is a rubber composition in which butyl rubber is blended with natural rubber in order to increase the loss coefficient.

division Parts by weight Example Comparative Example 1 Comparative Example 2 Rubber EPDM (KEP-7141, Kumho Polychem Co., Ltd.) 100 - Natural rubber (SMR CV60, Kumho Polychem Co., Ltd.) - 100 60 Butyl rubber (BR-IIR 2244, Kumho Polychem Co., Ltd.) - - 40 weapon
Filler Carbon Black (N330, Corax) 35 45 40 Crosslinking agent Hwang (Miwon) - 0.5 0.4 Di- (2-t-butylperoxyisopropyl) benzene 3 - - Bridge
accelerant Triaryl Cyanurate (TAC) 1.5 - - Triaryl Isocyanurate (TAIC) 1.5 - - Carbon Black (N330, Corax) - 2 2 Dibenzothiazyl disulfide
(DM, Crompton) - 1.5 1.5 Tetramethylthiuram disulfide
(TT, Dongyang Steel Chemical Co., Ltd.) - 1.5 1.5 Plasticizer Paraffin oil (Michang Petrochemical Co., Ltd.) 15 - - Aging
Inhibitor N-isopropyl-N'-phenyl-p-phenylenediamine (Crompton) 2 2 2 N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine
Crompton 2 2 2 2-mercapto benzimidazole
(Qingdao rubber chemical company) 1.5 1.5 1.5 2,2,4-trimethyl-1,2-dihydroquinoline
Bayer 2 2 2 Sunnox Wax (Sunnoc) 2 2 2 Processing aid Stearic acid 2 2 2 Zinc oxide 2 8 8 KEP-7141: Contains 51% Ethylene, Pattern Viscosity 27, Weight Average Molecular Weight 260,000

Test Example

In order to evaluate the rubber specimens and products prepared in Examples and Comparative Examples 1 and 2 were tested for the following items and the results are shown in Table 2 below and compared and evaluated.

Hardness measurement of the dynamic damper rubber was performed according to KS M 6784.

The tensile strength of the dynamic damper rubber was measured with dumbbell type 3 according to KS M 6782.

The evaluation of the aging property of the dynamic damper rubber recorded the change in physical properties after aging at 100 ° C. for 240 hours.

The natural frequency of the dynamic damper was measured by excitation at 1G after being fastened to the jig.

The loss coefficient of the dynamic damper rubber was recorded with the conditions of 3% static strain and 0.1% dynamic strain while raising the temperature from -100 ° C to 150 ° C using DMTA equipment.

Test Items Example Comparative Example 1 Comparative Example 2 State Property Hardness (Hs) 45 50 46 Tensile strength (kgf / cm ² ) 100 244 195 Aging Hardness change (△ Hs) +3 +5 +4 Tensile Strength Change Rate (%) +4 -22 -21 Natural frequency change rate (%) -20 ° C 26 35 173 100 ℃ -27 -20 -30 Loss factor 0.12 0.05 0.18

As shown in Table 2, compared to the rubber material using natural rubber or butyl rubber blended with natural rubber as in Comparative Examples 1 to 2, the EPDM material of the Example changes in hardness and tensile strength after aging at 100 ° C. for 240 hours. It was found to be excellent in heat resistance.

In the low temperature range, the natural frequency change rate was excellent in Examples compared to Comparative Examples 1 and 2, and especially 1/7 compared to Comparative Example 2 in which butyl rubber was blended to increase the loss coefficient. In the high temperature region, slightly worse than Comparative Example 1, but appeared better than Comparative Example 2. The loss coefficient was slightly lower than that of Comparative Example 2, which is a formulation for increasing the loss coefficient, but was twice as good as that of Comparative Example 1.

Claims (7)

100 to 150 parts by weight of ethylene-propylene (EPDM) rubber;
10 to 30 parts by weight of paraffin oil;
20 to 50 parts by weight of the inorganic filler;
1 to 10 parts by weight of the peroxide crosslinking agent;
1 to 10 parts by weight of crosslinking accelerator; And
Antioxidant 1 ~ 10 parts by weight
Rubber composition comprising a.
The rubber composition according to claim 1, wherein the ethylene-propylene rubber has a weight average molecular weight of 260,000 to 270,000, a pattern viscosity of 20 to 30, and an ethylene content of 40 to 60 wt%.
The inorganic filler of claim 1, wherein the inorganic filler is at least one filler selected from the group consisting of calcium carbonate, talc, clay, silica, mica, titanium dioxide, carbon black, graphite, ulastonite, and nanosilver. Rubber composition.
The method of claim 1, wherein the peroxide crosslinking agent is dicumyl peroxide, 1,1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane, di- (t-butylperoxyisopropyl) benzene , Butyl-4,4-bis (tert-butyldioxy) valerate, di- (2,4-dichlorobenzoyl) -peroxide, di- (2,4-dichlorobenzoyl) -peroxide, dibenzoyl peroxide , t-butyl peroxybenzoate, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane, di-t-butylperoxide, 2,5- Rubber composition, characterized in that at least one member selected from the group consisting of dimethyl-2,5-di (t-butylperoxy) hexim-3.
The method of claim 1, wherein the crosslinking accelerator is at least one selected from the group consisting of triarylcyanurate, triarylisocyanurate, trimethylolpropane trimethacrylate, ethylene dimethacrylate and sulfur. Rubber composition.
According to claim 1, wherein the anti-aging agent is dihydroquinoline, N-phenyl-N'-isopropyl-p-phenylenediamine (N-Phenyl-N'-isopropyl-p-phenylenediamine), or a mixture thereof The rubber composition characterized by the above-mentioned.
A dynamic damper comprising the rubber composition of any one of claims 1 to 6.