KR20060023199A - A rubber composition for engine mount with improved heat and age resistance - Google Patents

Abstract

The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, and more particularly, to an engine mount rubber composition comprising a rubber matrix, a filler, a sulfur, a vulcanization accelerator, and an activator, wherein the rubber matrix is made of natural rubber and isoprene. Fatty acid having an aryl group as the active agent, including an effective vulcanization system including rubber compounding rubber, carbon black FEF and carbon black MT having different particle sizes, and having a weight ratio of sulfur to the vulcanization accelerator of 0.5 or less. The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, which is improved by including a zinc salt of which improves heat resistance of the engine mount rubber and can suppress environmental natural aging and heat aging.

Engine Mount, Isoprene Rubber, Effective Vulcanization System, Heat Resistance, Aging Resistance

Description

A rubber composition for engine mount with improved heat and age resistance}

The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, and more particularly, to an engine mount rubber composition comprising a rubber matrix, a filler, a sulfur, a vulcanization accelerator, and an activator, wherein the rubber matrix is made of natural rubber and isoprene. Fatty acid having an aryl group as the active agent, including an effective vulcanization system including rubber compounding rubber, carbon black FEF and carbon black MT having different particle sizes, and having a weight ratio of sulfur to the vulcanization accelerator of 0.5 or less. The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, which is improved by including a zinc salt of which improves heat resistance of the engine mount rubber and can suppress environmental natural aging and heat aging.

An engine mount refers to a vehicle body fixing part that serves to support the engine and to prevent the vibration of the engine from being transmitted directly to the vehicle body. These engine mounts must have both a stiffness that can support heavy engines and a viscosity that can insulate the various vibrations of the high and low frequencies generated by the engine.

It is preferred that rubber be used as the material for the engine mount, and such polymer materials are generally accompanied by a drop out phenomenon due to mechanical fatigue and environmental factors. In particular, it is located in the engine room of an automobile, and the rubber is withdrawn due to the oxidation phenomenon due to the high heat generated from the engine and the repetitive vibration generated according to the terrain during driving, and thus cracks may occur, causing the rubber material to have heat resistance and aging resistance. Need development

As a result, studies to find the optimum mixing condition of the engine mount rubber that requires various physical properties at the same time have been continued. As raw material rubber for engine mount rubber, natural rubber with high strength at the time of vulcanization is generally used. By adding specific additives, not only mechanical properties such as tensile strength, permanent deformation, and durability required by the engine mount are required. Inventions that have improved heat resistance have been disclosed (Korean Patent No. 384041, Korean Patent No. 410220, etc.). However, these inventions tend to generate high-temperature heat while driving in accordance with the recent high performance of automobiles, and as the engine room becomes compact, the engine room atmosphere temperature rises and the rubber part ages due to the heat or the rubber's initial performance. There is a problem such as lowering it was necessary to improve it.

Subsequently, various studies related to the development of engine mounts using heat resistant rubbers such as chloroprene rubber have been made in the field of manufacturing rubber for engine mounts in order to prepare for a tendency of high temperature of the application environment. In particular, Korean Patent Laid-Open Publication No. 2004-0000852 focuses on the fact that natural rubber generally has a double bond, which is vulnerable to heat in rubber molecules, thereby limiting heat resistance. Thus, ethylene-propylene diene rubber (EPDM) is used instead of natural rubber. A rubber composition for an engine mount using a rubber was proposed, but in the case of the present invention, durability, heat resistance and the like were improved, but it was insufficient to suppress environmental natural aging or aging due to heat.

In Korean Patent No. 410857, an attempt has been made to improve long-term aging resistance by using an effective vulcanization system free of active amines, but this technique has a problem of lowering heat resistance, focusing on room temperature durability. Moreover, domestic automakers and others aim to extend the durability life of 100,000 miles in 10 years, and the engine room temperature gradually rises and exceeds 100 ℃ due to the advancement of technology due to the recent increase in vehicle performance and regulation of exhaust environment. As a result, it is urgent to develop an engine mount rubber that can withstand high temperatures and withstand the environmental natural aging required by the engine mount or heat aging.

Accordingly, the present inventors have made efforts to solve such a conventional problem, and in the engine mount rubber composition comprising a rubber matrix, a filler, a sulfur, a vulcanization accelerator and an activator, a combination of natural rubber and isoprene rubber instead of the conventional rubber An effective vulcanizing system comprising rubber as a rubber matrix, carbon black FEF and carbon black MT having different particle sizes as fillers, and having a weight ratio of the sulfur to the vulcanization accelerator of 0.5 or less instead of using a general vulcanizing system. And using zinc salts of fatty acids having an aryl group as the activator completed the present invention by improving the heat resistance of the engine mount rubber and suppressing environmental natural aging and heat aging.

Therefore, the present invention is a combination of natural rubber and isoprene rubber, carbon black FEF and carbon black MT of different particle sizes, sulfur of sulfur and vulcanization accelerator and aryl group having a weight ratio of sulfur to the vulcanization accelerator is less than 0.5 It is an object of the present invention to provide an engine mount rubber composition comprising a salt.

In addition, the present invention has another object to provide an engine mount rubber prepared using the engine mount rubber composition.

The present invention relates to an engine mount rubber composition comprising a rubber matrix, a filler, a sulfur, a vulcanization accelerator and an active agent, wherein the rubber matrix comprises 40 to 50:60 to 50% by weight of natural rubber and isoprene rubber; Carbon black FEF having a particle diameter of 40 to 48 nm and carbon black MT having a particle diameter of 201 to 500 nm as the filler; And zinc salts of fatty acids having an aryl group as the activator, 13 to 17 parts by weight of the carbon black FEF, 13 to 17 parts by weight of the carbon black MT, and 100 parts by weight of the natural rubber and isoprene rubber. 0.9 to 1.2 parts by weight of zinc salt of the fatty acid having an aryl group and 1.9 to 2.2 parts by weight, wherein the weight ratio of the sulfur to the vulcanization accelerator is 0.5 or less engine mount rubber composition and the engine mount rubber prepared from the composition It is characterized by.

The present invention will be described in more detail as follows.

The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, and more particularly, to an engine mount rubber composition comprising a rubber matrix, a filler, a sulfur, a vulcanization accelerator, and an activator, wherein the rubber matrix is made of natural rubber and isoprene. Fatty acid having an aryl group as the active agent, including an effective vulcanization system including rubber compounding rubber, carbon black FEF and carbon black MT having different particle sizes, and having a weight ratio of sulfur to the vulcanization accelerator of 0.5 or less. The present invention relates to an engine mount rubber composition having improved heat resistance and aging resistance, which is improved by including a zinc salt of which improves heat resistance of the engine mount rubber and can suppress environmental natural aging and heat aging.

The engine mount rubber composition of the present invention is an essential component of the rubber matrix, filler, sulfur, vulcanization accelerator and activator.

As a rubber matrix, rubber mixed with natural rubber (NR) and isoprene rubber (cis-Polyisoprene Rubber (IR)) is used. It is preferable to use refined natural rubber, and refining natural rubber removes impurities such as proteins, thereby improving heat resistance. In addition, since isoprene rubber is a synthetic rubber closest to natural rubber, it is easy to use in combination with natural rubber, has excellent vibration absorption, and has excellent balance of physical properties.

By blending natural rubber and isoprene rubber, heat resistance and durability are improved compared with the prior art, and natural rubber and isoprene rubber are preferably used in a ratio of 40 to 50:60 to 50% by weight.

The filler uses carbon black having different particle sizes. Carbon black uses carbon black FEF having a particle diameter of 40 to 48 nm and carbon black MT having a particle size of 201 to 500 nm when classified according to ASTM (AMERICAN STANDARD TEST METHOD). Carbon black HAF (particle diameter 26-30 nm), which has been widely used in the past due to high modulus and tear strength, has a limitation in using in engine mounts due to poor dynamic characteristics and heat resistance, and thus uses carbon black supplemented thereto. Carbon black FEF is used to improve heat resistance and carbon black carbon black MT is used to improve dynamic properties. The content of the carbon black FEF and the carbon black MT is preferably contained 13 to 17 parts by weight based on 100 parts by weight of the rubber compound. If the content is less than 13 parts by weight, the hardness is low, the static (Static) property is lowered, the mechanical properties are lowered, if the content is more than 17 parts by weight, the hardness is high, the static properties are too high, the ride comfort and damping may be weakened.

The vulcanization process is intended to cure the rubber by bonding sulfur to the rubber matrix and to exhibit the mechanical properties of the rubber. A system combining sulfur and vulcanization accelerators is called vulcanization. The vulcanizing system can be selectively used according to the structure and properties of rubber and the required physical properties of the product. Generally, the vulcanizing system is classified into a conventional vulcanizing system and an effective vulcanizing system. Among them, the general vulcanization system is composed of 1 to 3 parts by weight of relatively high amount of sulfur and a small amount of vulcanization accelerator and forms polysulfide crosslinking, and the effective vulcanization system is 0.5 parts by weight or less of sulfur and relatively high amount of vulcanization It consists of an accelerator and is characterized by forming a monosulfide crosslink. Therefore, in order to produce rubber having excellent heat resistance as in the present invention, it is more preferable to vulcanize using an effective vulcanization system rather than a general purpose vulcanization system in which sulfur bonds can be destroyed by heat.

The present invention is characterized by using an effective vulcanizing system having a weight ratio of sulfur to a vulcanization accelerator of 0.5 or less. General purpose vulcanization systems not only easily undergo reversion, but also degrade aging resistance. Accordingly, the heat resistance is improved by reducing the amount of sulfur by using an effective vulcanization system in which disulfide crosslinking occurs in a way to reduce reverse vulcanization and improve aging resistance as much as possible. In addition, the lowering of the fluidity and dynamic characteristics generated by using the effective vulcanization system can be reinforced by using two kinds of carbon blacks having different particle sizes as described above.

Sulfur is used as a crosslinking agent, and 0.9 to 1.2 parts by weight is good with respect to 100 parts by weight of the compounded rubber. If it is less than 0.9 parts by weight, the room temperature durability is significantly lowered, and if it exceeds 1.2 parts by weight, the heat resistance is lowered.

Vulcanization accelerator may be used without limitation, those conventionally used in rubber production. Examples thereof include N-cyclohexylbenzothiazole-2-sulfenamide (CZ), tetramethylthiuram disulfide (TT), N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS), and the like. It is more preferable to mix and use 2 or more types in the group which consists of these to show the effect which concerns on this invention.

The content of the vulcanization accelerator is preferably 0.5 to 3 parts by weight based on 100 parts by weight of the compounded rubber. When the vulcanization accelerator is included in less than 0.5 parts by weight, no effective vulcanization system is formed, and thus, the polysulfuric bond cannot be formed. When the vulcanization accelerator is added in excess of 3 parts by weight, a scorch may occur and a process defect may occur.

It is one of the important features of the present invention to necessarily include a zinc salt of a fatty acid having an aryl group as the active agent. Among the zinc salts of fatty acids with aryl groups are activators 73 and the like. The zinc salt of the fatty acid having an aryl group must be included as an activator, and metal oxides such as zinc oxide and magnesium oxide or metal carbonates such as zinc carbonate can be used together if necessary. In this way, the rubber's dynamic characteristics and processability are superior to those of conventional activators such as stearic acid, and heat resistance is remarkably improved.

The zinc salt of the fatty acid having an aryl group is preferably 1.9 to 2.2 parts by weight with respect to 100 parts by weight of the compounded rubber. If the content is less than 1.9 parts by weight, the activation of the vulcanization rate is weakened. This may cause a problem of weakened rubber properties. Moreover, 4.8-5.2 weight part is suitable with respect to 100 weight part of compounding rubbers, such as zinc oxide.

In the composition of the present invention, other additives commonly used in the production of engine mount rubber, in addition to the above components, may be used as necessary. For example, there exists a heat resistant antiaging agent, an ozone antiaging agent, a process oil, etc.

The anti-aging agent can be widely used as the conventional one, but it is preferable to use polymerized 2,2,4-trimethyl-1,2 dihydroquinoline. The anti-aging agent is preferably 0.9 to 1.1 parts by weight based on 100 parts by weight of the rubber compound. If it is less than 0.9 parts by weight, the heat resistance is weak, and if it exceeds 1.1 parts by weight, the room temperature durability may be reduced.

It is preferable to use N-phenyl-N'-isopropyl-p-phenylenediamine in order to improve heat resistance, bending resistance, and oxidation resistance as an ozone anti-aging agent. It is preferable to use 1.9 to 2.1 parts by weight based on 100 parts by weight of the ozone anti-aging agent, but if it is less than 1.9 parts by weight, ozone resistance may be weakened, and if it exceeds 2.1 parts by weight, oxidation resistance may be weakened.

PROCESS OIL improves dispersion, increases elongation and improves heat flow when formulated. In addition, it has an effect of preventing cracking and the like, thereby improving workability. The content is suitable for 3.8 to 4.2 parts by weight with respect to 100 parts by weight of the compounding rubber, if less than 3.8 parts by weight is poor workability, if the content exceeds 4.2 parts by weight there is a problem that the adhesiveness is weak.

The engine mount rubber may be manufactured using the rubber composition for engine mounting according to the present invention. The manufacturing method of the engine mount rubber is not limited to a specific method, but one general method that can be commonly used in the art to which the present invention pertains will be described in detail.

First, the blended rubber is used for 2 minutes in a Banbury mixer, and then carbon black is quantitatively added and kneaded for 10 minutes. Thereafter, additives such as vulcanization aids, activators and anti-aging agents are mixed and kneaded for 2 minutes to produce a carbon master batch. Sulfur and a vulcanization accelerator are added to the carbon master batch thus prepared and dispersed and mixed using a roll mixer. After measuring the appropriate vulcanization time using the flow rate meter using a flow meter, the rubber composition is heated and pressurized at 200 to 250 kgf / cm ² at 150 to 170 ° C using a compressor to prepare an engine mount rubber.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to Examples.

Examples and Comparative Examples

The engine mount rubber was prepared with the composition shown in Table 1 below.

division Ingredients (parts by weight) Example Comparative example Rubber matrix Natural rubber (NR) 50 100 Isoprene Rubber (IR) 50 - Filler Carbon black N330 - 27 Carbon black N774 15 - Carbon black N990 15 - sulfur sulfur 1.1 3 Vulcanization accelerator CZ 1.2 - TT One - MBTS - 0.1 MBT - 0.9 Active agent Aktivator 73 2 - S / ACID - 2 ZnO 5 5 Heat-resistant aging agent RD One One Ozone aging inhibitor 3C - 2 6C 2 - 654 - 2 Processing oil N-2 4 4 sum 147.3 147 NR: Refined natural rubber, Malaysia IR: Isoprene rubber, Malaysia carbon black N330: Korea carbon black, Corax N330 (HAF) carbon black N774: Korea carbon company, FEF carbon black N990: Canada KARB company, MT Sulfur: Midas , SP400 CZ: N-cyclohexylbenzothiazole-2-sulfenamide, Uniroyal Chemical Co., Ltd. TT: Tetramethylthiuram disulfide, Uniroyal Chemical Co., Ltd. MBTS: 2-mercaptobenzothiazole, Uniroyal Chemical Co., M MBT : Dibenzothiazil, Uniroyal Chemical, DM Aktivator 73: Germany STRUKTOL S / ACID: Stearic acid, CH ₃ (CH ₂ ) ₁₆ COOH, Uniroyal Chemical, ZnO: Zinc oxide, Zinc oxide, 99.5% RD : Polymerized 2,2,4-trimethyl-1,2 dihydroquinoline, Uniroyal Chemicals 3C: N-phenyl-N'-isopropyl-p-phenylenediamine, Kawaguchisa 6C: N-phenyl-N '-Isopropyl-p-phenylenediamine, Kawaguchisa

Experimental Example

The physical properties of the rubber specimens prepared in Examples and Comparative Examples were tested for the following items and the results are shown in Table 2.

Experimental Method

1. Hardness: measured according to KS M 6784.

2. Tensile strength and elongation: measured by dumbbell No. 3 in accordance with KS M 6782.

3. Aging: The change in physical properties was measured after aging at 85 ° C. for 1,000 hours.

4. Compressive permanent shrinkage: durability was measured after aging for 22 hours at 100 ℃.

Existing materials examined through the comparative example were developed with emphasis on room temperature durability, so that the physical properties at the high temperature dropped sharply, but the rate of change of physical properties after heat aging, which can be regarded as a measure of heat resistance, was remarkably improved. Conventionally, aging for 72 hours at 70 ℃ but in the case of the present invention by aging for 1000 hours at 85 ℃ ℃ environmental aging temperature has been developed an engine mount rubber that can suppress the occurrence of aging due to environmental natural aging and heat resistance.

As can be seen in Table 2, the tensile strength is 69%, the elongation is 54%, and the compression set is 30%.

 As described above, the engine mount rubber composition having improved heat resistance and aging resistance includes a blended rubber of natural rubber and isoprene rubber as a rubber matrix, and includes carbon black FEF and carbon black MT having different particle sizes as fillers. By using an effective vulcanization system having a weight ratio of sulfur to the vulcanization accelerator of 0.5 or less and activating vulcanization by using a zinc salt of an aryl group, the heat resistance of the engine mount rubber and environmental natural aging and aging resistance by heat are significantly improved. It is effective to let. The present invention can be applied not only to automobile engine mounts but also to mounts of other vehicles such as airplanes, and is expected to be widely applied to rubber compositions requiring both heat resistance and aging resistance at the same time.

Claims (6)

An engine mount rubber composition comprising a rubber matrix, a filler, sulfur, a vulcanization accelerator and an activator, Rubber in which the natural rubber and isoprene rubber are blended in the rubber matrix at 40 to 50:60 to 50% by weight; Carbon black FEF having a particle diameter of 40 to 48 nm and carbon black MT having a particle diameter of 201 to 500 nm as the filler; And zinc salts of fatty acids having aryl groups as the active agent, Zinc salt of a fatty acid having 13 to 17 parts by weight of the carbon black FEF, 13 to 17 parts by weight of the carbon black MT, 0.9 to 1.2 parts by weight of the sulfur and the aryl group based on 100 parts by weight of the natural rubber and isoprene rubber. It contains 1.9 to 2.2 parts by weight, Engine weight rubber composition, characterized in that the weight ratio of the sulfur to the vulcanization accelerator is 0.5 or less. 2. The engine mounted rubber composition of claim 1, wherein the active agent is an activator 73. The engine mount rubber composition according to claim 1, further comprising 0.9 to 1.1 parts by weight of an anti-aging agent based on 100 parts by weight of the natural rubber and isoprene rubber. The engine-mounted rubber composition according to claim 1, further comprising 1.9 to 2.1 parts by weight of an ozone anti-aging agent based on 100 parts by weight of the natural rubber and isoprene rubber. The engine-mounted rubber composition according to claim 1, further comprising 3.8 to 4.2 parts by weight of processing oil based on 100 parts by weight of the natural rubber and isoprene rubber. An engine mount rubber made from the engine mount rubber composition according to any one of claims 1 to 5.