CN111607163A

CN111607163A - Ethylene propylene rubber, raw material composition thereof, lifting lug, preparation method and application thereof

Info

Publication number: CN111607163A
Application number: CN201910142585.3A
Authority: CN
Inventors: 黄开军; 吴季霞; 郑刚
Original assignee: Jiangsu Luoshi Vibration Control Co ltd
Current assignee: Jiangsu Luoshi Vibration Control Co ltd
Priority date: 2019-02-26
Filing date: 2019-02-26
Publication date: 2020-09-01

Abstract

The invention discloses ethylene propylene rubber, a raw material composition thereof, a lifting lug, a preparation method and application thereof. The raw material composition comprises: 100 parts of ethylene propylene rubber raw rubber, 3-10 parts of activator A, 0.5-2.5 parts of activator B, 3-6 parts of anti-aging agent, 1-2 parts of polyethylene glycol, 1-2 parts of silane coupling agent, 40-60 parts of carbon black, 4-15 parts of precipitated white carbon black, 4-15 parts of plasticizer, 2.5-4.5 parts of vulcanizing agent, 1.5-3.2 parts of auxiliary crosslinking agent A and 0.1-0.3 part of auxiliary crosslinking agent B; activator a comprises zinc oxide; the activator B is stearic acid; the flash point of the plasticizer is above 270 ℃; the vulcanizing agent is a peroxide vulcanizing agent; the auxiliary crosslinking agent A is an auxiliary crosslinking agent for a peroxide vulcanization system; the assistant crosslinking agent B is sulfur. The ethylene propylene rubber has more excellent high temperature resistance, longer service life and lower damping coefficient.

Description

Ethylene propylene rubber, raw material composition thereof, lifting lug, preparation method and application thereof

Technical Field

The invention relates to ethylene propylene rubber, a raw material composition thereof, a lifting lug, a preparation method and application thereof.

Background

The automobile engine exhaust system assembly comprises an exhaust manifold, an exhaust pipe, a silencer, a three-way catalyst and the like. Which is connected with the engine and fixed to the lower part of the automobile chassis by a lifting lug. The lifting lug bears the dead weight of an exhaust system and the superposed load caused by various excitations in the motion process of the automobile and the engine thereof. These excitations originate from engine piston motion, ground, windage, turning side forces, etc. The lifting lug needs to have certain rigidity and strength, so that the lifting lug has a supporting function and a long service life. The automobile engine exhaust system assembly is connected with an engine exhaust outlet and is excited by high frequency and wide frequency amplitude consistent with the engine ignition frequency. Therefore, the lifting lug also isolates or attenuates the vibration to be transmitted from the exhaust system assembly to the vehicle body, and has the functions of vibration isolation and noise reduction. Engine exhaust temperatures are very high causing the exhaust system operating temperatures to be very high. In particular the hot end, i.e. the end adjacent to the engine, is at a very high temperature. Therefore, the lifting lug needs to have a wide range of working temperatures, especially high temperature working conditions.

In order to meet the above requirements, the basic performance of the lifting lug must include: reasonable dynamic and static rigidity; sufficiently high breaking force and service life; a temperature usage range of sufficient magnitude. The manufacturing materials of the lifting lug are silicone rubber and ethylene propylene diene monomer.

The upper limit of the working temperature of a hot end lifting lug of the exhaust system assembly is generally 150 ℃, the extreme high temperature (instant or short-term) reaches 175 ℃, and the high-grade, medium-grade and high-grade price vehicle types generally adopt silicon rubber. The silicone rubber has a silicone chain structure, has excellent high and low temperature resistance, has a working temperature range of-60-300 ℃, and is particularly suitable for the high-temperature severe working conditions of an exhaust system. The silicon rubber has a low damping coefficient, and basically meets the high-frequency vibration isolation function of the hot-end lifting lug. Silicone rubber mechanical properties are somewhat poor, but damage and loss of life caused by excessive stretching in extreme conditions is addressed by optimizing the ear structure, such as the outer limiting band.

However, because silicone rubber is expensive (high performance silica gel costs around 60 yuan/kg, peroxide system ethylene propylene rubber compounds costs 15-30 yuan/kg), some vehicle models are often cost constrained and silicone rubber is not selected.

In fact, peroxide cure system ethylene propylene rubber is often used for medium and low grade, low grade cost vehicle applications. However, the working temperature range of the ethylene propylene rubber of the existing peroxide vulcanization system is-55-130 ℃, and the high temperature resistance is still insufficient compared with the working condition of a lifting lug at a hot end (as mentioned above, the upper temperature limit is generally 150 ℃, and the extreme high temperature reaches 175 ℃). In addition, the damping coefficient of the ethylene propylene rubber of the existing peroxide vulcanization system is similar to that of silica gel, is slightly higher, and basically meets the requirement of vibration isolation in a wider frequency range, but because the damping coefficient is still higher, the NVH control of the lifting lug manufactured by the rubber in the acceleration stage of high-speed running of an automobile is still not perfect and imperfect.

In summary, the conventional ethylene-propylene rubber with peroxide curing system has the following defects: the hot end lifting lug manufactured by the method has short service life due to insufficient high temperature resistance; the slightly higher damping coefficient results in poor NVH control during the acceleration phase of the vehicle running at high speed.

Therefore, the development of the ethylene propylene rubber for the lifting lug, which meets the requirements of the high-temperature working condition (-55-150 ℃, instantaneous or short-term 175 ℃) of the lifting lug at the hot end, has longer service life, lower damping coefficient, better NVH control efficiency in the acceleration stage of high-speed running of an automobile and lower cost, and can basically replace silicon rubber, is a technical problem to be solved in the field.

Disclosure of Invention

The invention provides a novel ethylene propylene rubber and a raw material composition thereof, a lug, a preparation method thereof and application thereof, aiming at overcoming the defects that in the prior art, the cost of silicon rubber serving as a hot-end lug material is too high, and in the prior art, ethylene propylene rubber of a peroxide vulcanization system serving as a hot-end lug material has insufficient high temperature resistance, short service life, slightly high damping coefficient and poor NVH control in an acceleration stage of high-speed driving of an automobile.

Compared with the existing silicon rubber, the ethylene propylene rubber prepared by the raw material composition of the ethylene propylene rubber has lower cost and can replace silicon rubber to be used as a rubber material for a hot-end lifting lug.

Compared with the existing ethylene propylene rubber of a peroxide vulcanization system, the ethylene propylene rubber prepared from the raw material composition of the ethylene propylene rubber is used as a rubber material for the hot-end lifting lug, has more excellent high-temperature resistance, meets the working condition of the hot-end lifting lug (minus 55-150 ℃, and instantaneous or short-term 175 ℃), has longer service life and lower damping coefficient, and has more excellent NVH control efficiency for a multi-cylinder engine automobile in the acceleration stage of high-speed running.

The invention solves the technical problems through the following technical scheme:

the invention provides a raw material composition of ethylene propylene rubber, which comprises the following components in parts by mass: 100 parts of ethylene propylene rubber raw rubber, 3-10 parts of activator A, 0.5-2.5 parts of activator B, 3-6 parts of anti-aging agent, 1-2 parts of polyethylene glycol, 1-2 parts of silane coupling agent, 40-60 parts of carbon black, 4-15 parts of precipitated white carbon black, 4-15 parts of plasticizer, 2.5-4.5 parts of vulcanizing agent, 1.5-3.2 parts of auxiliary crosslinking agent A and 0.1-0.3 part of auxiliary crosslinking agent B;

wherein the Mooney viscosity ML125 ℃ 1+4 of the ethylene-propylene rubber raw rubber is 67-77, the mass percent of ethylene in the ethylene-propylene rubber raw rubber is 60.5-61.5%, and the mass percent of Ethylidene Norbornene (ENB) in the ethylene-propylene rubber raw rubber is 3.84-4.28%; the activator A comprises zinc oxide; the activator B is stearic acid; the flash point of the plasticizer is above 270 ℃; the vulcanizing agent is a peroxide vulcanizing agent; the auxiliary crosslinking agent A is an auxiliary crosslinking agent for a peroxide vulcanization system; the assistant crosslinking agent B is sulfur.

In the above-mentioned raw material composition, in ML125 ℃ 1+4, M represents Mooney, L represents a large rotor, 125 ℃ represents a test temperature of 125 ℃, 1 represents preheating for 1 minute, and 4 represents a test for 4 minutes.

In the raw material composition, preferably, the ethylene propylene rubber raw rubber is ethylene propylene rubber A and ethylene propylene rubber B; the Mooney viscosity ML 1+4 at 125 ℃ of the ethylene-propylene rubber A is 80-90, the mass percent of ethylene in the ethylene-propylene rubber A is 60-65%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber A is 4.3-4.5%; the Mooney viscosity ML 1+4 at 125 ℃ of the ethylene-propylene rubber B is 20-25, the mass percent of ethylene in the ethylene-propylene rubber B is 55-60%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber B is 2.1-2.5%.

Wherein, the Mooney viscosity ML125 ℃ 1+4 of the ethylene propylene rubber A is preferably 86, the mass percent of ethylene in the ethylene propylene rubber A is 62%, and the mass percent of ethylidene norbornene in the ethylene propylene rubber A is preferably 4.5%. More preferably, the ethylene propylene rubber A is KEP 1030F, and the manufacturer is Korea brocade lake synthetic chemical company.

Wherein, the parts of the ethylene propylene rubber A are preferably 70 to 90 parts, and more preferably 80 parts.

Wherein, the Mooney viscosity ML125 ℃ 1+4 of the ethylene-propylene rubber B is 23, the mass percent of ethylene in the ethylene-propylene rubber B is 57%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber B is 2.3%. More preferably, the ethylene propylene rubber B is preferably KEP435, manufactured by Korea brocade lake chemical Co

Wherein, the parts of the ethylene propylene rubber B are preferably 10 to 30 parts, and more preferably 20 parts.

In the above raw material composition, the part of the activator a is preferably 7 to 10 parts, more preferably 8 to 10 parts, further more preferably 9 parts, and for example, may be 3 to 8 parts, 5 to 6 parts, or 5.5 parts.

In the above raw material composition, the zinc oxide may be zinc oxide prepared by an indirect method conventionally used in the art, for example, zinc oxide with a purity of 99.7 wt% may be produced by a superior grade zinc oxide (type I) produced by a zinc oxide factory in kefir, shanxi county, anhui province, and the raw material thereof is metal zinc ingot or zinc slag obtained by smelting.

In the above raw material composition, the activator a is preferably a mixture of zinc oxide and magnesium oxide.

The magnesium oxide can be industrial magnesium oxide which is conventionally used in the field, the magnesium oxide is preferably a high-quality product which meets HG/T2573 standard, such as magnesium oxide ZH-V3, and the manufacturer is tin-free Brilliant chemical group.

Wherein, the part of the magnesium oxide is preferably 1 to 4 parts, more preferably 2 to 3 parts, and further more preferably 2.5 parts.

Wherein the part ratio of the zinc oxide to the magnesium oxide is (3-8): (1-4).

In the above raw material composition, the part of the activator B is preferably 0.5 to 1.5 parts, more preferably 0.8 to 1.2 parts, and further more preferably 1.0 part.

In the above raw material composition, the stearic acid is preferably n-octadecanoic acid, and the n-octadecanoic acid is preferably type 1801 200 stearic acid (type 200 means quality standard of first grade), for example, type 1801 200 stearic acid commercially available from Shijiazhuang Taixin chemical Co., Ltd.

In the above raw material composition, the antioxidant is preferably present in an amount of 3.7 to 5 parts, more preferably 3.7 to 4.5 parts, and may be present in an amount of 4 parts, for example.

In the raw material composition, the anti-aging agent may be an anti-aging agent conventionally used in the art, and the anti-aging agent is preferably one or more of an anti-aging agent MB (2-mercaptobenzimidazole), an anti-aging agent RD (2,2, 4-trimethyl-1, 2-dihydroquinoline polymer) and an anti-aging agent BLE-W (a high-temperature condensation product of acetone and diphenylamine).

The antioxidant MB, the antioxidant RD and the antioxidant BLE-W may be commercially available products of the Ministry of chemistry, Ministry of south China, for example.

Wherein, the part of the antioxidant MB is preferably 1 to 2 parts, more preferably 1.5 parts.

Wherein, the part of the antioxidant RD is preferably 0.5-1.5 parts, and more preferably 1 part.

The part of the anti-aging agent BLE-W is preferably 1-2 parts, and more preferably 1.5 parts.

In the above raw material composition, the part of the polyethylene glycol is preferably 1.5 parts.

In the above raw material composition, the polyethylene glycol is preferably polyethylene glycol 4000 (PEG 4000), for example, the polyethylene glycol 4000 available from shenyang rapuxing fine chemical company ltd under the type of PEG 4000.

In the above raw material composition, the silane coupling agent is preferably used in an amount of 1.5 parts.

In the above-mentioned raw material composition, the silane coupling agent may be a silane coupling agent conventional in the art, preferably bis- (γ -triethoxysilylpropyl) tetrasulfide, for example, bis- (γ -triethoxysilylpropyl) tetrasulfide of type SI-69 available from Degussa, Germany.

In the above raw material composition, the carbon black is preferably used in an amount of 50 parts.

In the above-mentioned raw material composition, the carbon black is preferably carbon black N660, and may be, for example, carbon black of type N660 produced by the Qingdao plant of Degussa, Germany.

In the raw material composition, the part of the precipitated silica is preferably 4 to 12 parts, and more preferably 6 to 10 parts.

In the raw material composition, the precipitated silica may be precipitated silica conventionally used in the art, and for example, the precipitated silica may be precipitated silica available in a model number of VN3 from Degussa, germany.

In the above raw material composition, the plasticizer is preferably used in an amount of 5 to 15 parts, more preferably 8 to 12 parts.

In the above raw material composition, the plasticizer may be paraffin oil satisfying the flash point, which is conventional in the art. The flash point of the plasticizer is preferably 290 ℃ or higher, more preferably 290-310 ℃. The plasticizer may be, for example, a model Sunpar 2280 paraffin oil, commercially available from suntan oil corporation, usa, having a flash point of 300 ℃.

In the above raw material composition, the vulcanizing agent is preferably present in an amount of 3 to 4 parts, more preferably 3.5 parts.

In the above-mentioned raw material composition, the vulcanizing agent may be a peroxide vulcanizing agent conventionally used in the art, preferably di-t-butylperoxyisopropyl benzene (vulcanizing agent BIPB, commonly known as odorless DCP), and may be, for example, a vulcanizing agent sold by the company AkSunobel, the Netherlands under the model Perkadox 14S-FL (vulcanizing agent BIPB).

In the raw material composition, the part of the auxiliary crosslinking agent a is preferably 1.8 to 3 parts, more preferably 2 to 2.5 parts.

In the above raw material composition, the auxiliary crosslinking agent a may be a peroxide curing system auxiliary crosslinking agent conventionally used in the art, preferably TAIC (triallylisocyanurate), and may be, for example, a commercially available auxiliary crosslinking agent of TAIC type from the chemical general factory of liuyang in hunan.

In the above raw material composition, the auxiliary crosslinking agent B IS preferably insoluble sulfur, and may be, for example, a vulcanizing agent of type IS-60 manufactured by tiadinierre fine chemical corporation.

The invention also provides a preparation method of the ethylene propylene rubber, the raw material adopted by the preparation method is the raw material composition of the ethylene propylene rubber, and the preparation method is a conventional two-stage method in the field.

Wherein, the preparation method preferably comprises the following steps:

(1) mixing the ethylene propylene rubber raw rubber to obtain a mixture A;

(2) mixing the mixture A, the activator B, the anti-aging agent, the polyethylene glycol and the silane coupling agent to obtain a mixture B;

(3) mixing the mixture B, the carbon black, the precipitated white carbon black and the plasticizer, discharging rubber and discharging sheets to obtain rubber premixed rubber;

(4) and the rubber premixed rubber is plasticated after standing, and then is mixed with the vulcanizing agent, the auxiliary crosslinking agent A and the auxiliary crosslinking agent B, discharged, sliced and cooled to room temperature.

In step (1), the operation and conditions of the mixing may be conventional in the art. The mixing time is preferably 50s to 80s, more preferably 60s to 75s, further more preferably 65 s. The mixing temperature is preferably 15 ℃ to 80 ℃. The mixing is preferably carried out in an internal mixer.

In step (2), the operation and conditions of the mixing may be conventional in the art. The mixing time is preferably 20s to 40s, more preferably 28s to 35s, further more preferably 30 s. The mixing temperature is preferably 15-80 ℃. The mixing is preferably carried out in an internal mixer.

In step (3), the operation and conditions of the mixing may be conventional in the art. The mixing time is preferably 120s to 180s, more preferably 150s to 165s, and further more preferably 160 s. The mixing temperature is preferably 50 ℃ to 145 ℃, more preferably 135 ℃ to 145 ℃, and still more preferably 140 ℃. The mixing is preferably carried out in an internal mixer.

In step (3), generally, the mixing is completed when the rubber discharge condition is met, and a person skilled in the art knows whether the rubber discharge condition is met or not, and can investigate by monitoring the mixing temperature or mixing time to avoid the phenomenon that the rubber is excessively mixed to cause too low molecular weight or scorching, thereby affecting the comprehensive performance of the rubber. Preferably, the mixing temperature reaches 135-145 ℃, the mixing can be finished, and the rubber discharging is carried out, more preferably 140 ℃; or, preferably, the mixing time is 120s-180s, the mixing can be finished, and the rubber discharging is carried out, more preferably 150 s; further alternatively, the temperature and time of kneading may be set to meet the above criteria.

In the step (3), the mixing is preferably completed when the mixing temperature reaches 135-145 ℃, and more preferably 140 ℃. The mixing temperature is understood by those skilled in the art to mean the temperature of the mixing chamber.

In the step (3), the temperature of the binder removal is preferably 135 ℃ to 145 ℃, more preferably 138 ℃ to 143 ℃, and still more preferably 141 ℃. The discharge is preferably carried out in an internal mixer.

In step (3), the operation and conditions for the sheet production may be conventional in the art. The sheet discharge is preferably carried out in an open mill. The wheel pitch of the mill is preferably 2-5mm, more preferably 3 mm.

In step (4), the purpose of said resting is to ensure a better static dispersion of the gum, as known to the skilled person. The standing may be performed at room temperature. The time for the standing is preferably 12 to 48 hours, more preferably 22 to 36 hours, further more preferably 24 hours.

In step (4), the operations and conditions of the mastication may be conventional in the art. The time for the mastication is preferably 60s to 80s, more preferably 65s to 75s, further more preferably 70 s. The plastication is preferably carried out in an internal mixer.

In step (4), the operation and conditions of the mixing may be conventional in the art. The mixing time is preferably 90s to 150s, more preferably 105s to 120s, further more preferably 110 s. The mixing temperature is preferably 70 ℃ to 100 ℃, more preferably 80 ℃ to 100 ℃, and further more preferably 90 ℃ to 95 ℃. The mixing is preferably carried out in an internal mixer.

In step (4), generally, the mixing is completed when the rubber discharge condition is met, and a person skilled in the art knows whether the rubber discharge condition is met or not, and can investigate by monitoring the mixing temperature or mixing time to avoid the phenomenon that the rubber is excessively mixed to cause too low molecular weight or scorching, thereby affecting the comprehensive performance of the rubber. Preferably, the mixing temperature reaches 80-100 ℃, the mixing can be finished, and the rubber can be discharged, more preferably 95 ℃; or, preferably, the mixing time is 90s to 150s, the mixing can be finished, and the rubber discharging can be carried out, more preferably 120 s; further alternatively, the temperature and time of kneading may be set to meet the above criteria.

In the step (4), the mixing is preferably completed when the mixing temperature reaches 95 ℃. The mixing temperature is understood by those skilled in the art to mean the temperature of the mixing chamber.

In the step (4), the temperature of the rubber discharge is preferably 70 ℃ to 100 ℃, more preferably 75 ℃ to 99 ℃, and further more preferably 82 ℃. The discharge is preferably carried out in an internal mixer.

In step (4), the operation and conditions for the sheet production may be conventional in the art. The sheet discharge is preferably carried out in an open mill. The track of the open mill is preferably 2-5mm, more preferably 3 mm.

In step (4), typically, the product is contacted with an aqueous solution of release agent during the film discharge to prevent the surfaces of the film or blank from sticking to each other.

The release agent in the aqueous release agent solution can be a release agent conventionally used in the field, such as zinc stearate or magnesium stearate. The temperature of the aqueous solution of the release agent may be conventional in the art, and is preferably 40 ℃ or lower.

In step (4), the room temperature generally means that the ambient temperature is 10 to 35 ℃. Without the "cool to room temperature" operation, the ethylene propylene rubber risks scorching.

The invention also provides the ethylene-propylene rubber prepared by the preparation method of the ethylene-propylene rubber.

The invention also provides a lifting lug which is made of the ethylene propylene rubber through the conventional injection vulcanization process in the field. The lifting lug can be a hot-end lifting lug, for example.

The invention also provides an application of the ethylene propylene rubber as a material of a lifting lug at the hot end of an automobile exhaust system assembly.

On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows:

compared with the existing silicon rubber, the ethylene propylene rubber prepared from the raw material composition of the ethylene propylene rubber has the advantages of lower cost, more excellent tensile strength, impact resilience, tear strength and tensile strength, hot air aging resistance, compression permanent deformation, ozone resistance, low temperature resistance, dynamic and static rigidity, service life and road test performance equivalent to those of the silicon rubber, and can replace the silicon rubber to be used as a rubber material for a hot-end lifting lug.

Compared with the existing ethylene propylene rubber of a peroxide vulcanization system, the ethylene propylene rubber prepared from the raw material composition of the ethylene propylene rubber is used as a rubber material for a hot-end lifting lug, and has the advantages of more excellent tensile strength, elongation at break, impact resilience, tearing strength, hot air aging property, compression set property and dynamic stiffness, longer service life, lower damping coefficient, wider vibration isolation frequency range and more excellent NVH control efficiency of a multi-cylinder engine automobile in an acceleration stage of high-speed running.

The preparation method of the ethylene propylene rubber has simple steps and convenient operation, and is suitable for industrial production.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

The raw materials used in the examples and comparative examples of the present invention were derived as follows:

ethylene propylene rubber virgin rubber: ethylene propylene rubber A, an ethylene propylene rubber of KEP 1030F model number of Korea brocade lake synthetic chemical company, wherein the Mooney viscosity ML125 ℃ 1+4 is 86, the mass percent of ethylene is 62%, and the mass percent of ENB is 4.5%; ethylene-propylene rubber B, an ethylene-propylene rubber of KEP435 type available from Korea brochure chemical company, has a Mooney viscosity ML125 ℃ of 1+4 of 23, a mass percent of ethylene of 57%, and a mass percent of ENB of 2.3%.

An activator A: the zinc oxide is superior grade zinc oxide (I type) produced by zinc oxide factory in Jinhua county, Anhui province, and generally has the purity of 99.7% (w/w); the magnesium oxide is a high-purity magnesium oxide ZH-V3 sold by the tin-free Zezushi chemical group.

An activator B: model 1801 stearic acid, commercially available from Shijiazhuang Taixin chemical Co., Ltd.

An anti-aging agent: the anti-aging agent MB is a commercial product MB of the Ministry of chemistry and chemistry research; the antioxidant RD is a commercial product of the Ministry of chemistry and Ministry of China; the anti-aging agent BLE-W is a commercial product of southern group research institute.

Polyethylene glycol: shenyang Repuxing Fine chemical Co., Ltd is a polyethylene glycol 4000 available as PEG 4000.

Silane coupling agent: bis- (gamma-triethoxysilylpropyl) tetrasulfide from Degussa, Germany, under the type SI-69.

Carbon black: carbon black N660 is a carbon black having the type N660 as produced by the Qingdao plant of Degussa, Germany; carbon black N550 is a carbon black having the type N550 as manufactured by Degussa, Germany, Islands; carbon black N774 is a carbon black type N774 produced by Degussa, Germany, Islands, Inc. (Degussa).

And (3) white carbon black precipitation: precipitated silica, model VN3, is commercially available from Degussa, Germany.

Plasticizer: the American Sun Petroleum company has a commercial model number Sunpar 2280 paraffin oil with a flash point of 300 ℃.

Vulcanizing agent: the vulcanizing agent is marketed by Aksunobel, the Netherlands under the model Perkadox 14S-FL.

Auxiliary crosslinking agent A: the commercial model of the chemical general factory of Liuyang in Hunan is TAIC auxiliary crosslinking agent.

And (3) auxiliary crosslinking agent B: insoluble sulfur produced by Tai' an Tu fine chemical Co., Ltd, model IS IS-60.

V3666 in comparative example 1 is an ethylene propylene rubber commercially available from exxon petrochemicals, usa as model V3666.

The silicone rubber in comparative example 2 was a high tear strength silicone rubber compound having a hardness of 65A, which was prepared from two silicone rubber compounds, TR55 and TR70, in a TR55: TR70 mass ratio of 1: 2 by kneading. Wherein the silicone rubber compound with the model number of TR55 is a high-tear strength silicone rubber compound with the model number of TR55 of Dow Corning company; the silicone rubber compound of model TR70 was a high tear strength silicone rubber compound of model TR70 by dow corning incorporated, who added 0.65 parts (based on 100 parts of raw rubber in the above silicone rubber compound, and the parts are parts by mass) of bis-25 vulcanizing agent (2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane) to each of the two silicone rubber compounds. Wherein the hardness of TR55 vulcanized rubber is 55A, the breaking strength is 10MPa, and the breaking elongation is 775%; the hardness of TR70 vulcanized rubber is 70A, the breaking strength is 7.6MPa, and the breaking elongation is 550%.

Examples 1 to 5, comparative example 1 and comparative example 2

TABLE 1

In Table 1, "-" indicates "0" in parts; the Mooney viscosity is the Mooney viscosity ML125 ℃ C.1 + 4.

Examples 1 to 5

The ethylene-propylene rubber of each example is obtained by the following preparation steps of the raw material components of each example in the table 1 (the parameters of each step are shown in the table 2):

(1) putting the ethylene propylene rubber A and the ethylene propylene rubber B into an internal mixer, and mixing to obtain a mixture A;

(2) continuously adding zinc oxide, magnesium oxide, stearic acid, an anti-aging agent, polyethylene glycol and a silane coupling agent into the internal mixer, and mixing to obtain a mixture B;

(3) continuously adding carbon black, precipitated white carbon black and a plasticizer into the internal mixer, and carrying out mixing, rubber discharging and sheet discharging to obtain rubber premixed rubber;

(4) standing the rubber premixed rubber, putting the rubber premixed rubber after standing into an internal mixer for plastication, then continuously putting a vulcanizing agent, an auxiliary crosslinking agent A and an auxiliary crosslinking agent B into the internal mixer, and carrying out mixing, rubber discharging, sheet discharging and cooling to room temperature to obtain the rubber premixed rubber.

TABLE 2

As known to those skilled in the art, in the mixing process of the internal mixer, rubber is extruded and sheared by a rotor, and forced to flow or deform, so as to enter a carbon black structure gap, divide carbon black and surround the carbon black to form a carbon black-rubber block mass; the carbon black-rubber block mass is continuously stretched and sheared to be refined; the carbon black agglomerates are further broken, dispersed and homogenized to obtain a uniform and well-dispersed rubber compound. Generally, in the continuous kneading process, the temperature of the rubber composition is continuously increased. In practice, it is common in the art to use the end or start of a stage when the mixing temperature or mixing time reaches a certain set value. Therefore, in small steps of the mixing process, the mixing temperature is a variable and cannot be listed in Table 2 as a process parameter.

Comparative example 1, compounded by a two-stage process conventional in the art, the relevant parameters are shown in table 2, and the remainder is the same as in the examples.

Comparative example 2, two silicone rubber compounds of type TR55 and TR70 were used in a mass ratio TR55: TR70 of 1: 2, and kneading the mixture on an open mill. Firstly, putting the silicone rubber compound with the model number of TR70 on an open mill, mixing the silicone rubber compound with the model number of TR50 to a wrapping wheel, continuously feeding the silicone rubber compound with the model number of TR50 into the open mill, mixing and mixing for 3 minutes, then discharging 2mm sheets, packaging the sheets in a triangular bag for 10 times according to a conventional mixing method in the field, then discharging 5mm sheets, rolling 3 times according to the conventional mixing method in the field, and finally discharging 5mm sheets and cooling for later use. The rubber temperature in the mixing process is 20-60 ℃.

Effects of the embodiment

The rubber material products of examples 1 to 5, comparative example 1 and comparative example 2 were subjected to material tests, and the test results are shown in the following table 3:

TABLE 3

Remarking: the vulcanization test pieces were prepared according to the conventional method in the art (ASTM D3182, ASTM D3183), and the data in Table 3 were obtained by the test button test. Examples 1-5, comparative example 1 vulcanization conditions were 170 ℃ 10MPa 10min (three elements of vulcanization: temperature, time, pressure), a second vulcanization 180 ℃ 3 h; comparative example 2 the vulcanization conditions were 170 ℃ 10MPa 10min (three elements of vulcanization: temperature, time, pressure), a second vulcanization 200 ℃ 4 h. Hardness test (shore a) standard ASTM D2240 is performed; tensile strength, elongation at break standard ASTM D412; impact rebound execution standard ISO 4662; tear strength (right angle) test execution standard ASTM D624(Type C); low temperature test execution standard ASTM D2137; the ozone test performs the standard ASTM D1149.

As known to those skilled in the art, the rubber of the peroxide curing system generally needs to be cured twice, and the material performance can be more excellent and stable. During the first vulcanization, under the action of three elements of vulcanization, peroxide decomposes out free radicals to initiate rubber crosslinking reaction, and a rubber network structure is formed. However, the peroxide in the vulcanized rubber after primary vulcanization is not completely decomposed, and the residual peroxide vulcanizing agent causes unstable rubber performance. In practice, peroxide decomposition is calculated as half-life, and curing can be completed after completion of typically 4-5 half-lives. Therefore, it is a common practice in the art to continuously bake the primarily vulcanized rubber in an oven at a high temperature to sufficiently decompose the peroxide curing agent. The vulcanized rubber subjected to secondary vulcanization is more excellent in heat aging characteristics, creep characteristics and the like.

As can be seen from Table 3, examples 1-5 and comparative example 2 both satisfied the material specification requirements of the automobile factories. Compared with comparative example 2, the tensile strength, tear strength and impact resilience of the example are obviously more excellent; the hot air aging property change rate and compression set characteristics of the examples were comparable to those of comparative example 2, but the tensile strength of the examples was still high after hot air aging. It is also understood from Table 3 that the hot air aging resistance and the compression set of comparative example 1 do not satisfy the requirements of the automobile factory specifications.

It is known to the person skilled in the art that rubber elasticity is generally characterized by impact resilience, and in general the better the rubber elasticity, the relatively slightly lower the high-frequency dynamic stiffness of the rubber parts produced therefrom.

Manufacturing the hot-end lifting lug of the automobile exhaust system assembly by using the materials obtained in the examples 1-5 and the comparative examples 1-2 through a conventional injection vulcanization process in the field, wherein the vulcanization conditions of the examples 1-5 and the comparative example 1 are 170 ℃ by 10MPa by 10min (three vulcanization factors: temperature, time and pressure), and the secondary vulcanization is 180 ℃ by 3 h; comparative example 2 the vulcanization conditions were 170 ℃ 10MPa 10min (three elements of vulcanization: temperature, time, pressure), a second vulcanization 200 ℃ 4 h. The obtained hot end lifting lug is subjected to a tensile strength test and a dynamic and static rigidity test respectively, and the results are shown in table 4:

TABLE 4

Remarking: and (4) testing the static stiffness by adopting MTS static stiffness testing equipment. The stretching direction was from 0N to 200N at a loading speed of 10mm/min, and then from 200N to 0N at an unloading speed of 10 mm/min. A complete loading and unloading process is generally referred to as a test cycle. The pre-cycle was 3 times, no loading for 3-4 minutes, after which the fourth test was performed. And taking the static stiffness according to the fourth loading stress strain value and the curve thereof. And (4) testing dynamic stiffness by adopting MTS dynamic stiffness testing equipment.

As can be seen from Table 4, the above tests of examples 1 to 5 and comparative example 2 both satisfied the specification of the materials for automobile factories, but the tensile strength of the examples was higher, that is, the tensile properties were better, as compared with comparative example 2. However, the dynamic stiffness of comparative example 1 is too high to meet the requirements of the car factory specifications.

As known to those skilled in the art, for example, in-line 4-cylinder engine, when the automobile is idling, the engine speed is 600-; at high acceleration, the engine speed is 3000RPM, corresponding to an ignition frequency of 100 Hz. Therefore, the coverage of 15-100Hz by the truck factory design criteria actually evaluates the NVH control efficiency over a wide frequency range. Based on this, it can be seen from table 4 that the dynamic stiffness of each frequency of comparative example 1 is relatively high, and the high frequency is higher and more serious; compared with the comparative example 1, the examples 1 to 5 can keep better dynamic stiffness within the test frequency range of 15 to 100Hz, so that the NVH control efficiency of the automobile in the acceleration stage of high-speed running is more excellent.

Furthermore, as those skilled in the art know, the lower the dynamic stiffness, the lower the damping coefficient at the same test frequency, so that the damping coefficient is lower for examples 1-5 in the 15-100Hz range compared to comparative example 1.

As can also be seen from the above table, the dynamic stiffness of the material of the embodiment in the test frequency range of 15-100Hz meets the requirement, so the material can adapt to the vibration frequency of 15-100 Hz; in contrast, the comparative example 1 has no dynamic stiffness meeting the requirements within the test frequency range of 15-100Hz, so that the comparative example cannot adapt to the vibration frequency of 15-100 Hz. Based on this, the vibration isolation frequency range of the material of the embodiment is wider.

Manufacturing the hot-end lifting lug of the automobile exhaust system assembly by using the materials obtained in the examples 1-5 and the comparative examples 1-2 through a conventional injection vulcanization process in the field, wherein the vulcanization conditions of the examples 1-5 and the comparative example 1 are 170 ℃ by 10MPa by 10min (three vulcanization factors: temperature, time and pressure), and the secondary vulcanization is 180 ℃ by 3 h; comparative example 2 the vulcanization conditions were 170 ℃ 10MPa 10min (three elements of vulcanization: temperature, time, pressure), a second vulcanization 200 ℃ 4 h. The obtained hot end lifting lugs are subjected to a bench durability test respectively, and the results are shown in table 5:

TABLE 5

As can be seen from table 5, the laboratory benches of examples 1-5 have better durability performance than comparative example 1. In other words, it can be seen from the above data that the working life of examples 1 to 5 is longer than that of comparative example 1.

Manufacturing the hot-end lifting lug of the automobile exhaust system assembly by using the materials obtained in the examples 1-5 and the comparative examples 1-2 through a conventional injection vulcanization process in the field, wherein the vulcanization conditions of the examples 1-5 and the comparative example 1 are 170 ℃ by 10MPa by 10min (three vulcanization factors: temperature, time and pressure), and the secondary vulcanization is 180 ℃ by 3 h; comparative example 2 the vulcanization conditions were 170 ℃ 10MPa 10min (three elements of vulcanization: temperature, time, pressure), a second vulcanization 200 ℃ 4 h. The obtained hot end lifting lugs are respectively provided for a car factory to carry out a bench simulation endurance test and a road test, and the results are shown in table 6:

TABLE 6

As can be seen from Table 6, the ordinary road tests and the reinforced road tests of examples 1 to 5 and comparative example 2 satisfy the requirements of the vehicle manufacturer. Comparative example 1 no road test was done because the dynamic stiffness was not acceptable.

In conclusion, the dynamic stiffness of the comparative example 1 is unqualified, and the vibration isolation requirements of related wide frequency and high frequency cannot be met; in comparative example 2, although the rubber material performance, the dynamic and static stiffness, the durability of the laboratory bench and the road test meet the requirements of the vehicle and factory indexes, the material cost is higher than that of the embodiment by more than 100%. Therefore, the ethylene propylene rubber of the embodiment is cheaper and can completely replace silicon rubber to be used as the material of the hot-end lifting lug of the automobile exhaust system assembly.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.

Claims

1. The raw material composition of the ethylene propylene rubber is characterized by comprising the following components in parts by mass: 100 parts of ethylene propylene rubber raw rubber, 3-10 parts of activator A, 0.5-2.5 parts of activator B, 3-6 parts of anti-aging agent, 1-2 parts of polyethylene glycol, 1-2 parts of silane coupling agent, 40-60 parts of carbon black, 4-15 parts of precipitated white carbon black, 4-15 parts of plasticizer, 2.5-4.5 parts of vulcanizing agent, 1.5-3.2 parts of auxiliary crosslinking agent A and 0.1-0.3 part of auxiliary crosslinking agent B;

wherein the Mooney viscosity ML125 ℃ 1+4 of the ethylene-propylene rubber raw rubber is 67-77, the mass percent of ethylene in the ethylene-propylene rubber raw rubber is 60.5-61.5%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber raw rubber is 3.84-4.28%; the activator A comprises zinc oxide; the activator B is stearic acid; the flash point of the plasticizer is above 270 ℃; the vulcanizing agent is a peroxide vulcanizing agent; the auxiliary crosslinking agent A is an auxiliary crosslinking agent for a peroxide vulcanization system; the assistant crosslinking agent B is sulfur.

2. The raw material composition of ethylene propylene rubber according to claim 1, wherein the ethylene propylene rubber raw rubber is ethylene propylene rubber A and ethylene propylene rubber B; the Mooney viscosity ML 1+4 at 125 ℃ of the ethylene-propylene rubber A is 80-90, the mass percent of ethylene in the ethylene-propylene rubber A is 60-65%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber A is 4.3-4.5%; the Mooney viscosity ML 1+4 at 125 ℃ of the ethylene-propylene rubber B is 20-25, the mass percent of ethylene in the ethylene-propylene rubber B is 55-60%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber B is 2.1-2.5%;

wherein, the Mooney viscosity ML125 ℃ 1+4 of the ethylene-propylene rubber A is preferably 86, the mass percent of ethylene in the ethylene-propylene rubber A is 62%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber A is preferably 4.5%;

wherein, the parts of the ethylene propylene rubber A are preferably 70 to 90 parts, and more preferably 80 parts;

wherein, the Mooney viscosity ML125 ℃ 1+4 of the ethylene-propylene rubber B is 23, the mass percent of ethylene in the ethylene-propylene rubber B is 57%, and the mass percent of ethylidene norbornene in the ethylene-propylene rubber B is 2.3%;

3. The raw material composition of ethylene-propylene rubber according to claim 1, wherein the activator A is present in an amount of 7 to 10 parts, preferably 8 to 10 parts, more preferably 9 parts;

and/or the activator A is a mixture of zinc oxide and magnesium oxide; wherein the parts of the zinc oxide and the magnesium oxide are preferably (3-8): (1-4);

and/or the activator B is 0.5 to 1.5 parts, preferably 0.8 to 1.2 parts, and more preferably 1.0 part;

and/or the stearic acid is n-octadecanoic acid.

4. A starting composition for ethylene-propylene rubber according to any of claims 1 to 3, wherein the antioxidant is present in an amount of 3.7 to 5 parts, preferably 3.7 to 4.5 parts, more preferably 4 parts;

and/or the anti-aging agent is one or more of 2-mercaptobenzimidazole, 2, 4-trimethyl-1, 2-dihydroquinoline polymer and a high-temperature condensation product of acetone and diphenylamine;

and/or the polyethylene glycol is 1.5 parts;

and/or, the polyethylene glycol is polyethylene glycol 4000;

and/or 1.5 parts of silane coupling agent;

and/or the silane coupling agent is bis- (gamma-triethoxysilylpropyl) tetrasulfide;

and/or the carbon black accounts for 50 parts;

and/or, the carbon black is carbon black N660;

and/or, the precipitated white carbon black is 4-12 parts, preferably 6-10 parts;

and/or the plasticizer is 5-15 parts, preferably 8-12 parts;

and/or the plasticizer is paraffin oil;

and/or the flash point of the plasticizer is above 290 ℃, preferably 290-310 ℃;

and/or, the vulcanizing agent is 3-4 parts, preferably 3.5 parts;

and/or the vulcanizing agent is di-tert-butyl cumene peroxide;

and/or the part of the assistant crosslinking agent A is 1.8-3 parts, preferably 2-2.5 parts;

and/or the auxiliary crosslinking agent A is triallyl isocyanurate;

and/or the auxiliary crosslinking agent B is insoluble sulfur.

5. The raw material composition of ethylene-propylene rubber according to claim 4, wherein the antioxidant is a mixture of 2-mercaptobenzimidazole, 2, 4-trimethyl-1, 2-dihydroquinoline polymer and high-temperature condensate of acetone and diphenylamine;

wherein, the part of the 2-mercaptobenzimidazole is preferably 1 to 2 parts, more preferably 1.5 parts;

wherein, the part of the 2,2, 4-trimethyl-1, 2-dihydroquinoline polymer is preferably 0.5-1.5 parts, more preferably 1 part;

wherein, the part of the acetone and diphenylamine high-temperature condensate is preferably 1-2 parts, and more preferably 1.5 parts.

6. A preparation method of ethylene-propylene rubber is characterized in that raw materials adopted by the preparation method of the ethylene-propylene rubber are the raw material composition of the ethylene-propylene rubber as claimed in any one of claims 1 to 5, and the preparation method of the ethylene-propylene rubber is a two-stage method.

7. The method for preparing ethylene-propylene rubber according to claim 6, characterized in that the method comprises the following steps:

(1) mixing the ethylene propylene rubber raw rubber to obtain a mixture A;

8. Ethylene-propylene rubber, characterized in that it is obtained by the process for the preparation of ethylene-propylene rubber according to claim 6 or 7.

9. A shackle made from the ethylene propylene rubber of claim 8; the lifting lug is preferably a hot end lifting lug.

10. Use of the ethylene-propylene rubber according to claim 8 as a material for a lifting lug at the hot end of an automobile exhaust system assembly.