KR20100090445A - Epdm elastomers for highly extended comounds and method of preparing thereof - Google Patents

Abstract

PURPOSE: An ethylene-alpha-olefin-diene elastomer and a manufacturing method thereof are provided to secure the excellent roll workability and extrusion processibility, and to improve the mechanical property of the elastomer during a highly extended combination. CONSTITUTION: A manufacturing method of an ethylene-alpha-olefin-diene elastomer comprises a step of forming the elastomer using a Ziegler-Natta catalyst system at a reactor including directly connected first and second reactors. The ethylene-alpha-olefin-diene elastomer contains 50~70wt% of manufacturing component for the first reactor, and 30~50wt% of manufacturing component for the second reactor.

Description

Ethylene-alphaolefin-diene (EPDM) copolymer for high filling formulations and a method for producing the same {EPDM ELASTOMERS FOR HIGHLY EXTENDED COMOUNDS AND METHOD OF PREPARING THEREOF}

The present invention relates to an ethylene-alpha olefin-diene (EPDM) copolymer having excellent workability such as roll workability and extrusion workability, good molding surface, and excellent mechanical properties even at high filling compounding, and a method of manufacturing the same. .

Ethylene-alphaolefin-diene rubber is a non-polar rubber material having no double bond in the main chain, and has excellent weatherability, ozone resistance, thermal stability, and electrical properties, and has been applied to various industrial parts including automotive parts. In particular, in the field of rubber materials for hoses and automotive weather strips, there is a constant demand for rubber compositions having excellent extrusion processability, good molding surface, and excellent shape retention, and in addition, high filling formulations for economic efficiency such as manufacturing cost reduction. There is a further need for high molecular weight elastomers having a sufficient molecular weight to be applied to the present invention.

A typical example of high molecular weight EPDM with sufficient molecular weight for high filling formulations is the Nordel MG product developed by Dow in 2003. Dow combined its metallocene catalyst with gas-phase technology to produce EPDM products with significantly higher molecular weight levels than before, producing commercial products that can be used for automotive hoses, weather strips or TPV applications. This product has the advantage of being suitable for the high filling formulation because of the low deterioration of mechanical properties such as the tensile strength even when the high filling formulation is used. Disadvantages such as difficulty in handling and being limited by the choice of carbon black formulations have been pointed out.

From the technical point of view, the conventional techniques, which have been attempted to secure the physical properties and processability of high molecular weight EPDM rubbers, can be classified into two types and introduced a long chain branch by the diene reaction. This is how to make a multimodal copolymer from several reactors connected in series.

US 4,722,971 utilizes an intermolecular compositional distribution of ethylene and dienes to selectively distribute high diene and propylene content to the low molecular weight components that make up the majority of the copolymer, and to yield some high molecular weight components up to millions of molecular weights. It has been reported that the processability and vulcanization characteristics of the compound rubber are improved through the multimodal copolymer rubber configured to increase the ethylene content on the side.

In WO 00/26296, the composition of some high molecular weight components (Money viscosity (ML1 + 4, 125 ° C.) 80 to 120) corresponding to 20 to 50% by weight of the whole is distributed in such a manner that the ethylene content is high and the Mooney viscosity is high. It was reported that the high propylene content was distributed in a number of low molecular weight components ranging from 1/5 to 1/20 of the molecular weight component, thereby overcoming the problem of poor workability due to the narrow MWD, which is a disadvantage of the metallocene catalyst system.

These techniques commonly comprise a large number of low-molecular weight components of hundreds of thousands of conventional copolymers in the production of multimodal copolymers composed of high molecular weight components and low molecular weight components, in which the ethylene content is particularly high. As a method of introducing a small amount of millions of ultra-high molecular weight components, it has an advantage in the structure easy to control the structure compared to the long chain branch by the diene. However, in order to apply to a high filling formulation of 550 phr or more, which is increased by more than 100 phr from the conventional formulation, the Mooney viscosity (ML1 + 4, 125 ° C) of the entire copolymer should be at least 100 very high molecular weight product. As such, it is difficult to produce high molecular weight products having such a high level of requirement as to introduce a small amount of high molecular weight components. Moreover, when increasing the ratio of high molecular weight components having high ethylene content and very high molecular weight, solvent separation and drying during the manufacturing process are difficult. In addition, machinability problems persist in a series of post-processing processes such as kneading, blending, and processing. When manufacturing high molecular weight copolymer rubber with such condensed milk, a method of lowering the Mooney viscosity by adding extender oil has been commonly used in order to secure processability and processability after polymerization. In order to lower the final Mooney viscosity of (ML1 + 4, 125 ℃) to less than 100, the amount required from 0 to 100 phr has been added in the polymerization step. However, when extender oil is added to the polymerized rubber, oil is already added to the raw material rubber, which limits the amount of oil available during the mixing and processing of the latter stage. In this case, since a substantial amount of oil is already contained in the raw material rubber, the proportion of the raw material rubber is increased, and thus the economic effect is greatly reduced even if a high filling compound is formed.

In the present invention, while using the Ziegler-Natta catalyst system that has been traditionally used in EPDM products, the ethylene content of the high molecular weight constituting the majority of the entire copolymer is distributed so as to be 10 to 20% by weight lower than the low molecular weight component, and the content of diene is increased. A multimodal copolymer of asymmetric differential composition was constructed so as to be 1 to 4 times higher than the low molecular weight component. This makes it possible to have a sufficiently high molecular weight compared to the existing rubber composition to greatly increase the content of the filler, and to make it easy to process without using extender oil, which is usually used in the manufacture of high molecular weight products. Gene formulations provide an economic advantage that can dramatically reduce the cost of manufacturing rubber products.

An object of the present invention is to provide an ethylene-alphaolefin-diene (EPDM) copolymer having excellent processability such as roll processability and extrusion processability, a good molding surface, and excellent mechanical properties even at high filling compounding.

Another object of the present invention is a copolymer having a high molecular weight level enough to retain excellent mechanical properties even in high-fill formulations, and is easy to handle and process without using an extender oil, which is usually used in the manufacture of a high molecular weight polymer. It is possible to significantly reduce the cost of manufacturing rubber products by constructing the economic benefits to rubber product producers.

The present invention uses a Ziegler-Natta catalyst system from two reactors connected in series to prepare an asymmetric multimodal copolymer having different ethylene and diene contents of relatively high and low molecular weight components. do.

Specifically, the present invention provides a method for preparing asymmetric multimodal copolymers having different molecular weights and compositions from two series-connected reactors using a Ziegler-Natta catalyst system, wherein half of the total copolymers in the first reactor are prepared. Ethylene-alphaolefin-diene (EPDM) copolymers characterized by polymerizing high molecular weight components that account for the above, but structurally modifying them to exhibit excellent processability and mechanical properties by lowering the ethylene content below the average value and increasing the diene content above the average value. It provides a composition and a method for producing the same.

The present invention provides a method for preparing an ethylene-alphaolefin-diene copolymer using a Ziegler-Natta catalyst system in two series-connected reactors of a first reactor and a second reactor, wherein the ethylene-alphaolefin-diene copolymer The molecular weight of the component polymerized in each reactor to include 50 to 70% by weight of the first component (A) and 30 to 50% by weight of the second component (B) in terms of the copolymer composition, It provides a method for producing an ethylene-alpha olefin-diene copolymer for producing a multimodal copolymer having an asymmetric composition with different compositions.

(1) MW (A)> MW (B)

(2) A1 <(A1 + 2 × B1) / 3

(3) A3> (A3 + 2 × B3) / 3

MW (A): Molecular weight of first reactor production component

MW (B): Molecular Weight of Second Reactor Preparation Component

A1: Ethylene Content (wt%) of First Reactor Preparation Component

B1: Ethylene Content (wt%) of Second Reactor Preparation Component

A3: diene content (% by weight) of the first reactor preparation component

B3: diene content (% by weight) of the second reactor preparation component

(A1 + 2 × B1) / 3: average ethylene content (% by weight) of the entire copolymer

(A3 + 2 × B3) / 3: average diene content (% by weight) of the entire copolymer

The molecular weight of each reactor preparation component of the present invention can be represented by Mooney viscosity (ML1 + 4,125 ° C.).

The present invention also provides an ethylene-alpha olefin-diene copolymer prepared by the above production method.

The ethylene-alphaolefin-diene copolymer prepared according to the present invention has a Mooney viscosity (ML1 + 4, 125 ° C) of 50 to 200, an ethylene content of 50 to 80% by weight and a diene content of 3 to 3 of the entire copolymer. 10 wt% ethylene-alphaolefin-diene copolymer, comprising a high molecular weight copolymer component and a low molecular weight copolymer component in a 70/30 to 50/50 weight ratio, wherein the composition of the high molecular weight copolymer component is a composition of a low molecular weight copolymer component In comparison, the ethylene content is at least 10% by weight or more, preferably 15% by weight or more, and the diene content is characterized by consisting of an asymmetric structure of at least 1 to 4 times or more, preferably 1.5 to 3 times or more.

Hereinafter, manufacturing features to be implemented in the present invention will be described in detail.

1) Formation of high molecular weight elastomer and high extender oil for high filling formulation

In order to secure the extrudability, the raw material rubber to be used for the rubber product for extrusion requires a high ethylene content with a high molecular weight. In particular, if the purpose is to increase the content of carbon black, oil and other compounding agents to reduce the specific gravity of the raw material rubber, the raw material rubber having a higher molecular weight is required.

The ethylene-alpha olefin-diene copolymer of the present invention preferably has a Mooney viscosity (ML1 + 4, 125 ° C) of 50 to 200, more preferably 150 to 200 of the ethylene-alpha olefin-diene copolymer To provide.

From the standpoint of raw material rubber production, the preparation of high molecular weight raw material rubbers with a Mooney viscosity (ML1 + 4, 125 ° C) of 100 or more in the existing manufacturing process using the Ziegler-Natta catalyst system requires considerable effort. It is difficult to increase productivity due to the limited activity of the NATA catalyst, and when the high molecular weight product having a Mooney viscosity of 100 or more is produced, the viscosity of the polymer solution may increase rapidly or the risk of gel generation increases, and the burden of equipment is increased during solvent separation and drying. There are various process problems such as deterioration of processability of the produced product. For this reason, high molecular weight elastomers have been commonly used to reduce the Mooney viscosity by adding an extender oil in order to secure the processability and processability after polymerization, and according to the molecular weight of the polymer, the extender oil (Extender) The amount of oil added was determined to lower the Mooney viscosity (ML1 + 4, 125 ° C) of the final product to 100 or less.

However, when the extender oil is added to the polymerized rubber, oil is already added to the raw material rubber. Therefore, the amount of oil that is available during the mixing and processing of the latter stage is restricted and further, the high filling compound is added. In the case of obtaining economic benefits such as cost reduction through the process, since the substantial amount of oil is already contained in the raw material rubber, the economic effect is greatly reduced even if a high filling compound is formed.

Therefore, in the present invention, instead of using an extender oil while manufacturing a sufficiently high molecular weight product so that it can be suitably used for the rubber product for extrusion processing, it is easy to process the high molecular weight copolymer by controlling the composition by molecular weight segment. Focused on providing.

In addition, the rubber composition using the ethylene-alpha olefin-diene copolymer of the present invention can be suitably applied to the manufacture of rubber products for low hardness formulation in addition to the rubber products for extrusion processing, the physical properties required for the rubber products of the same application In order to achieve a high strength, it may contain a certain amount of extender oil for the purpose of imparting a low hardness while having a higher molecular weight than the extrusion use. In other words, the rubber product for low hardness compounding is composed so that the amount of process oil used in the compounding to make the hardness low is relatively higher than other uses, and a certain amount of oil is included in the raw material rubber in the form of an extended oil in advance. This can make compounding and processing easy. In this case, too, by using the structural characteristics of the differential composition of the molecular weight segment of the present invention, it is possible to minimize the amount of extender oil or to give excellent processing characteristics when using the same extender oil.

2) Increased alpha olefin content of high molecular weight copolymerization component to impart processability

Ethylene-alpha olefin-diene copolymer of the present invention is a method for producing an ethylene-alpha olefin-diene copolymer containing 50 to 80% by weight of ethylene, 3 to 10% by weight of diene and the remaining amount of alpha olefin To provide.

In order to impart suitable properties to extrudates such as automotive weather strips, the ethylene content of the entire copolymer should preferably be comprised in the range of 50 to 80% by weight, more preferably 60 to 70% by weight. If it is less than%, there is a disadvantage in that the green strength is low and the extrudability or the tensile strength is weakened. If the ethylene content exceeds 80% by weight, there is a problem in that a gel (Gel) is greatly generated during polymerization.

The alpha olefins that can be used in the present invention are preferably branched, linear, cyclic and substituted or unsubstituted aromatic compounds, and more preferably high olefins having 3 to 18 carbon atoms. Examples are propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 3-methyl-1 -Hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 3-ethyl-1-pentene, 1-octene, 3-methyl-1-heptene, 4-methyl-1-heptene, 5-methyl -1-heptene, 6-methyl-1-heptene, 3-ethyl-1-hexene, 4-ethyl-1-hexene, 3-propyl-1-pentene, 1-deken and the like, the most preferred of which are As the thing, propylene is mentioned.

When preparing copolymers having different molecular weights and compositions using reactors connected in series, the ethylene content of the high molecular weight copolymerization components is higher than the average value until the composition of the entire copolymer is composed of many low molecular weight components and a few high molecular weight components. The high and low molecular weight copolymers were most often configured such that the ethylene content was below the average.

However, in the copolymer of the present invention, since the high molecular weight copolymer component accounts for 50 to 70% by weight of the total copolymer, the crystalline structure is configured so that the alpha olefin content such as propylene is higher than the average of the total copolymer in the high molecular weight copolymer component. And low-molecular weight copolymer components, which account for 30 to 50% by weight of the total copolymer, may be configured to have an ethylene content higher than the average value to match the overall composition.

The present invention provides a method for producing an ethylene-alphaolefin-diene copolymer, wherein the ethylene content (A1) of the component prepared in the first reactor and the ethylene content (B1) of the component prepared in the second reactor satisfy the following formula. to provide.

(4) 10% by weight ≤ A1-B1 ≤ 20% by weight

A1: Ethylene Content (wt%) of First Reactor Preparation Component

B1: Ethylene Content (wt%) of Second Reactor Preparation Component

The present invention prepares a high molecular weight component corresponding to 50 to 70% by weight of the total copolymer in the first reactor and the ethylene content of the same high molecular weight component is 10 to 20% by weight than the ethylene content of the low molecular weight component produced in the second reactor. It provides a method for producing an ethylene-alpha olefin-diene copolymer characterized by imparting excellent roll processability and extrusion processability by designing the ethylene distribution in an asymmetric differential composition so as to have a low%.

The ethylene content of the high molecular weight component in the copolymer of the present invention is designed to be at least 3% by weight or more, preferably at least 7% by weight, lower than the average ethylene content of the entire copolymer, and the composition ratio of the high molecular weight component and the low molecular weight component Accordingly the ethylene content difference between the two components is designed to be as much as 10 to 20% by weight.

In order to confirm the implementation of the compositional distribution (compositional distribution) intended in the present invention, the distribution of Short chain branch (SCB) content for each molecular weight segment was analyzed using GPC-IR (Model: PL-GPC220). It can be seen that the composition of the ethylene / propylene is changed according to.

In FIG. 1, short chain branch (SCB) contents different from each other in structure are described. Short chain branch (SCB) is a concept for measuring the relative ratio of ethylene and propylene in a chain by counting the number of side chain structures in an alpha olefin such as propylene. (Linear PE) calculates SCB based on 12 CH ₂ and CH ₃ as two pairs of socks. Branched polyethylene (CH) is added by branched propylene to branched linear chain. _{Add 2} 3 and 3 CH ₃ to calculate the SCB content in each chain.

Figure 2a is a distribution of the short chain branch (SCB) measured by GPC-IR of the same composition copolymer for each reactor, Figure 2b is measured by GPC-IR of the differential composition copolymer according to a preferred embodiment of the present invention Distribution of short chain branches (SCB).

Referring to FIG. 2A, since both ends of the chain, as well as both ends of the chain, are regarded as short chain branches (SCB), the lower molecular weight chains have a higher ratio of SCBs. It appears that more SCBs are distributed on the lower molecular weight side.

On the other hand, referring to Figure 2b, in the case of the differential composition copolymer provided by the present invention shows that the SCB of the high molecular weight chain portion is significantly increased above the average, through which the propylene content of the high molecular weight component as intended in the present invention It can be confirmed that it is higher than the average value, and due to such structural properties, although the copolymer of the present invention is made of a very high level of high molecular weight chains, it is possible to secure excellent processability such as flexible rubber material and good extrusion properties. It became.

3) Increased diene monomer content of high molecular weight copolymerization components to enhance vulcanization and mechanical properties

The present invention provides a method for producing an ethylene-alphaolefin-diene copolymer in which the diene content (A3) introduced into the first reactor and the diene content (B3) introduced into the second reactor satisfy the following formula.

(5) B3≤A3≤4 × B3

A3: diene content (% by weight) of the first reactor preparation component

B3: diene content (% by weight) of the second reactor preparation component

The present invention provides a high molecular weight component corresponding to 50 to 70% by weight of the total copolymer in the first reactor and the diene content of the high molecular weight component is 1 to 4 times the diene content of the low molecular weight component produced in the second reactor. By providing an asymmetric differential composition of the diene distribution, the present invention provides a method for producing an ethylene-alpha olefin-diene copolymer, which has fast vulcanization rate, high crosslinking density, and excellent mechanical properties, compared to when manufactured with the same diene distribution. .

The diene monomer which can be used in the present invention is preferably a linear, branched hydrocarbon diolefin or cycloalkenyl substituted alkene structure having 5 to 15 carbon atoms, and having at least two double bonds. For example, 1,4- Hexadiene, 1,5-hexadiene, 1,5-heptadiene, 1,6-heptadiene, 1,6-octadiene,, 1,7-octadiene, 1,7-nonadiene, 1,8- Nonadiene, 1,8-decadiene, 1,9-decadiene, 1,12-tetradecadiene, 1,13-tetradecadiene, 3-methyl-1,4-hexadiene, 3-methyl-1, 5-hexadiene, 3-ethyl-1,4-hexadiene, 3-ethyl-1,5-hexadiene, 3,3-dimethyl-1,4-hexadiene, 3,3-dimethyl-1,5- Hexadiene, 5-vinyl-2-norbornene, 2,5-norbornane diene, 7-methyl-2,5-norbornadiene, 7-ethyl-2,5-norbornadiene, 7-propyl-2, 5-norbornadiene, 7-butyl-2,5-norbornadiene, 7-phenyl-2,5-norbornadiene, 7-hexyl-2,5-norbornadiene, 7,7-dimethyl-2, 5-norbornadiene, 7-methyl-7-ethyl-2,5-norbornadiene, 7-chloro-2,5-norbornadie N, 7-bromo-2,5-norbornadiene, 7-fluoro-2,5-norbornadiene, 7,7-dichloro-2,5-norbornadiene, 1-methyl-2,5- Norbornadiene, 1-ethyl-2,5-norbornadiene, 1-propyl-2,5-norbornadiene, 1-butyl-2,5-norbornadiene, 1-chloro-2,5-norbornadiene Ene, 1-bromo-2,5-norbornadiene, 5-isopropyl-2-norbornene, 1,4-cyclohexadiene, bicyclo (2,2,1) hepta-2,5-diene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, bicyclo (2,2,2) octa-2,5-diene, 4-vinylcyclohexa-1-ene, bicyclo (2 , 2,2) octa-2,6-diene, 1,7,7-trimethylbicyclo- (2,2,1) hepta-2,5-diene, dicyclopentadiene, petyltetrahydroindene, 5 -Arylbicyclo (2,2,1) hepta-2-ene, 1,5-cyclooctadiene, 1,4-diarylbenzene, butadiene, isoprene, 2,3-dimethylbutadiene-1,3, 1, 2-butadiene-1,3,4-methylpentadiene-1,3,1,3-pentadiene, 3-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3 -Ethyl-1,3-pentadiene, and most Preferably from 5-ethylidene-2-norbornene (ENB) and dicyclopentadiene (DCPD) is used a lot.

In the rubber composition of the present invention, the content of the diene monomer is generally adjusted to be in the range of 3 to 10% by weight, and when the diene content is less than 3% by weight, the crosslinking properties are insufficient, such as insufficient crosslinking and high permanent compression ratio. On the other hand, when the diene content is more than 10% by weight, scorch may be generated, or gelation may occur during kneading, and problems such as unintentional microfoaming in molding processes such as extrusion are likely to occur.

In the case of high filling formulations, it is common that the compounding properties, which were implemented at conventional conventional blending amounts, are not properly implemented. This is due to the fact that the proportion of raw material rubber in the total compounded rubber becomes smaller as it is increased with several times carbon black, process oil, calcium carbonate, clay, silica and other compounding aids in addition to the raw material rubber. Maintaining the required level of physical properties is a key task of high-filling rubbers.

Thus, in the construction of a rubber composition for manufacturing rubber products, the main material EPDM rubber (Ethylene Propylene Diene Monomer Rubber) is used as the ethylene-alpha olefin-diene copolymer of the present invention, carbon black, process oil, hard coal, silica , Comprising a rubber composition comprising a crosslinking agent and a crosslinking accelerator, wherein the total amount of the rubber composition is composed of 500 to 600 phr of a high filling compound, such that the amount of the ethylene-alphaolefin-diene copolymer is 0.01 to 20% by weight. It is to be included in%, and together with the rubber composition characterized in that the physical properties of the high-filling compound rubber satisfies the Compound Strength Retainment Coefficient (CSRC) 0.65 or more.

 (6) CSRC = 1-| (Tensile strength change rate according to change of total compounding amount) |

          = 1-| (Tensile strength of compound 1-tensile strength of compound 2) / (mixture amount of compound 1-compounding amount of compound 2) |

Tensile strength in the above formula is the result measured in accordance with ASTM D412.

The rubber composition including the ethylene-alpha olefin-diene copolymer of the present invention preferably has a tensile strength change rate (mixing strength retention coefficient, CSRC) of 0.65 or more, in particular, in the range of 0.70 to 1 It is more desirable to maintain the tensile strength even at high filling to satisfy the. If the blending strength maintenance factor is less than 0.65, the mechanical properties of the rubber composition are greatly reduced due to the increase of the filling amount, so that it is impossible to implement the required physical properties of the rubber products for each use, and thus it cannot be suitably applied to high filling formulations.

Therefore, the present invention was intended to maximize the crosslinking efficiency in order to reduce the physical properties of the compound rubber in addition to the work to increase the molecular weight of the EPDM rubber to a high filling compound, the diene content of the entire copolymer for the same content The diene content of the high molecular weight component and the low molecular weight component were at least two times different while maintaining a high concentration of the diene monomer on the high molecular weight copolymerizing component to maximize the crosslinking density. The crosslink density was compared relative to the maximum vortex torque (M _H ) results in the moving direometer (MDR) vulcanization test. As a result, the rubber composition of the present invention showed a maximum increase in the maximum vortex torque (M _H ) in the moving die rheometer (MDR) vulcanization test, compared to the conventional rubber composition having the same diene content, vulcanized rubber Tensile strength was increased by more than 10% in the tensile properties of the same rubber composition, it was confirmed that the effect of improving the physical properties by the differentiation of the diene monomer, that is, the distribution of dienes in the high molecular weight chain.

The high molecular weight ethylene-alpha olefin-diene copolymer rubbers presented in the present invention have a high level of high molecular weight so that they can be preferably applied to high-fill formulations, but they have an extended oil as a structural property according to the differential composition. Since it is easy to knead and process without the help of the oil, it is very different from the oil-extended EPDM, which is mainly applied for the same purpose, in terms of economic efficiency such as reducing the mixing cost. In addition, when using the copolymer rubber of the present invention when the high-filling formulation has the strength of maintaining the compounding level of 75% or more required in the conventional compounding amount, it is applied to the extrudates for hoses and automotive rubber parts, etc. The commercial value is expected to be very large.

*Test Methods

1) Banbury mixer processability evaluation

The blended rubber was put into a Banbury mixer set at 50 ° C., kneaded for 4 minutes, and then dumped to evaluate the kneaded state divided into the following three grades.

Rating Explanation Prize Raw rubber is kneaded evenly with compounding ingredients medium Although the kneading condition is relatively good, sometimes the mixing agent such as carbon black and oil is mixed unevenly Ha Compound rubber is broken and broken

2) Roll workability evaluation

The blended rubber was wound up for 3 minutes at the temperature of the front roll and the back roll at 50 degreeC, and the processability was divided into three grades, and evaluated.

Rating Explanation Prize Rubber band is tightly adhered to the roll, and the bank is sufficiently formed to rotate smoothly medium Rubber bands often come off or stick to the surface of the roll Ha Rubber band breaks off or breaks into pieces

3) Ribbon appearance evaluation

The ribbon surface appearance evaluation criteria of the extrudate were evaluated as the smoothness of the surface. If the surface was smooth, the surface was uneven, and if the surface was not glossy or rough, the surface unevenness was as severe as the turtle shell.

4) Extrusion workability evaluation

Extrusion processability was evaluated by comprehensively evaluating the extrudability by measuring the surface, length, weight and thickness of the band to be extruded by inserting the compound rubber in the extruder set to 60 ℃ and passed through a slit-shaped mold of width 2mm at a speed of 15rpm.

Die swelling for evaluating dimensional stability is calculated by the following equation (7).

(7) Die Swell (%) = [(A _Extrudate -A _Die ) / A _Die ] × 100

= [Q / ρ / L / A _Die -1] × 100

Here, A _Extrudate represents the cross-sectional area of the extrudate (cm ² ), A _Die represents the cross-sectional area of the extrusion _die (cm ² ), and Q, ρ, L represent the weight, specific gravity, and linear velocity of the extrudate, respectively.

5) Measurement of Monetary Viscosity

A Mooney viscometer (MV2000, Alpha Technologies, Inc.) used a large rotor at 125 ° C., measured and read 4 minutes after the start of the rotor at 1 minute of preheating, and expressed as ML1 + 4 (125 °).

6) GPC-IR measurement

A sample dissolved in 1,2,3-trichlorobenzene (TCB) solvent was permeated through a PLOlexis column (15 μm) at a rate of 1.0 mL / min at 160 ° C to PL-GPC 220 connected to FT-IR (Varian Excalibur HE3100). The average molecular weight and the chain composition for each molecular weight segment were measured using. Polystyrene and polyethylene were used as standards for molecular weight and short chain branch (SCB) calibration, respectively.

Example 1

In the continuous polymerization system, two reactors connected in series are filled with normal hexane up to 50% level, and then a predetermined composition is implemented to realize a differential composition in which the composition of the high molecular weight component of the first reactor and the low molecular weight component of the second reactor is asymmetrically composed. Propylene / ethylene was added to the reactor differently according to each reactor. In order to form a high molecular weight component, the polymerization temperature of the first reactor was sufficiently lowered to 45 ° C. and the polymerization temperature of the second reactor was increased to 55 ° C., so that the molecular weight difference between the components produced from the two reactors became clear, and the Ziegler-Natta catalyst was used. By employing the system, vanadium oxy trichloride (VOCl ₃ ) and ethyl aluminum sesquichloride (EASC) were added at an Al / V = 5 weight ratio, respectively, to initiate the reaction. Hydrogen was added as a chain transfer agent, but by adjusting the amount of hydrogen injected into each reactor in consideration of the polymerization temperature and the catalyst usage, the molecular weight of each reactor and the total copolymer were adjusted. In this example, 3 Nm 3 /Hr.Ton of hydrogen was injected into the first reactor and 0.5 Nm 3 /Hr.Ton of the second reactor. After the reaction was stopped, monomer recovery and washing were carried out, and the copolymer rubber was obtained by separating the solvent from the solvent using steam at 90 to 98 ° C. The Mooney viscosity of the copolymer was 87 (ML1 + 4 @ 125 ° C.), and the Mooney viscosity measurement value of the high molecular weight sample obtained separately in the first reactor and the low molecular weight component Mooney viscosity value of the second reactor using the formula (8) Were 113 and 54, respectively.

(8) Log ML _OVERALL = f ₁ * Log ML ₁ + f ₂ * Log ML ₂

Here, ML _OVERALL , ML ₁ and ML ₂ denote the Mooney viscosity of the entire copolymer, the high molecular weight component of the first reactor, and the low molecular weight component of the second reactor, and f ₁ , f ₂ are the first reactor, the second It is the weight fraction of reactor production.

The composition of the copper copolymer and the high molecular weight sample was analyzed by infrared spectroscopy, respectively. As a result, the copolymer had an ethylene content of 67% by weight and a diene content of 5.7% by weight. As 6.7% by weight, it was confirmed that ethylene was lower and diene was higher than the total copolymer average.

Example 2

The Mooney viscosity of the copolymer was 130 (ML1 + 4) as a result of the same procedure as in Example 1 except that the amount of hydrogen as a chain transfer agent was reduced to 70% of Example 1 to increase the Mooney viscosity of the copolymer. @ 125 ° C.), and the Mooney Viscosity measurements of the high molecular weight sample obtained separately from the first reactor and the Mooney Viscosity values of the second reactor using the formula (8) were 169 and 80, respectively. Analysis of the composition of the copper copolymer and the high molecular weight sample by infrared spectroscopy showed that the copolymer had an ethylene content of 67% by weight and a diene content of 5.9%. The high molecular weight sample of the first reactor had an ethylene content of 62% by weight and a diene content of 7.1. It was confirmed that ethylene was lower than the total copolymer as a weight% and diene was higher.

Example 3

As a result of the same procedure as in Example 1, except that the amount of hydrogen as a chain transfer agent was reduced to 50% of Example 1 to increase the Mooney viscosity of the copolymer and 50 phr of Extender Oil was added. The Mooney viscosity of the copolymer was 190 (ML1 + 4 @ 125 ° C), and the Mooney viscosity of the final product with Extender Oil was 54 ML1 + 4 @ 125 ° C. The composition of the copper copolymer and the high molecular weight sample was analyzed by infrared spectroscopy, respectively. The copolymer had 70 wt% ethylene content and 5.7 wt% diene content, and the high molecular weight sample sample was 72 wt% ethylene content and diene content in the first reactor. 6.7% by weight.

Comparative Example 1

For comparison with the differential composition multimodal copolymers of Examples 1 to 3, instead of the differential composition in which the composition of the high molecular weight component of the first reactor and the low molecular weight component of the second reactor is asymmetrically composed of the first reactor and the second reactor Equal composition copolymers having the same propylene / ethylene / diene content were prepared.

The copolymer configurations of Examples 1 to 3 and Comparative Example 1 are shown in <Table 1>.

TABLE 1

Copolymer Construction of Examples 1 to 3 and Comparative Example 1

NOTE 1 The Mooney viscosity of the low molecular weight component of the second reactor is calculated by equation (8)

Note 2) Tan Delta was determined by a frequency sweep test at 100 ° C, 7% strain, and 10.47 rad / s using RPA2000 (Rubber Processability Analyzer).

100 wt% of the copolymer of Examples and Comparative Examples were included to form a blend according to the formula of <Table 2>. Formulation 1 of <Table 2> consists of a conventional level of compounding amount that can be applied in the manufacture of extrusion commercial products, such as automotive solid weather strip, Formulation 2 is a high filling by increasing the amount of compounding materials, such as carbon black and oil It was configured to mix.

Each compound was kneaded at a rotational speed of 60 rpm for 4 minutes using a Banbury mixer (capacity of 1.7 liters) set at 50 ° C to obtain a compounded compound rubber. The compound was cooled to room temperature and then roll workability and sheet surface were evaluated and extrusion workability was evaluated.

TABLE 2

Formulas applied to Examples 1, 2 and Comparative Example 1

[Table 3]

Evaluation of workability of Examples 1 and 2 and Comparative Example 1 according to the formulation (Formulations 1 and 2 of <Table 2>)

Note 1) How to write workability: ① Upper (satisfied) ② Medium (normal), ③ Lower (bad)

Note 2) Appearance of Ribbon: ① Upper (satisfied) ② Medium (normal), ③ Lower (bad)

As shown in Table 3, in the case of a conventional compounding amount (compound 1), all of Examples 1, 2 and Comparative Example 1 showed relatively similar results in terms of compound Mooney viscosity and extrusion processability. However, when composed of a high filling formulation (compound 2) of 550 phr or more, the high molecular weight product of Example 2 showed good processability results without significant change in processability despite increasing filling amount, whereas Comparative Examples 1 and 1 were compound Mooney Viscosity was greatly increased, kneading was not good, extrusion length was shortened and die swelling was increased even in extrusion test, and roll workability was not suitable for high filling formulations.

[Table 4]

Evaluation of physical properties of Examples 1, 2 and Comparative Example 1 according to the high filling formulation (Formulation 2 of [Table 2])

<Vulcanization Characteristics>

TABLE 5

<Mechanical characteristics>

TABLE 6

Compound Strength Retainment Coefficient (CSRC)

(6) CSRC = 1-| (Tensile strength change rate according to change of total compounding amount) | = 1-| (Tensile strength of Formulation 1-Tensile strength of Formulation 2) / (Formulation amount of Formulation 1-Formulation amount of Formulation 2) |

As shown in the physical property results of Table 4, it can be seen that in high-filling formulations, the tensile properties of the compounded rubbers decrease as the specific gravity of the raw material rubbers in the compound decreases. At 400 phr, which is a typical level, all of the samples shown showed high tensile strength, but when the blended amount was 550 phr or more, the degree of deterioration was changed according to the difference in the molecular weight and the diene content in the high molecular weight component. As in the case of Example 2, the copolymer having a very high Mooney viscosity and having a high diene content in the high molecular weight chain has a relatively small decrease in mechanical properties, so that the compound strength retention coefficient (CSRC) satisfies 0.7 or higher. It can be preferably applied to.

1 is a comparative view of the short chain branch (SCB) by structure.

Figure 2a is a distribution diagram of the short chain branch (SCB) measured by GPC-IR of the conventional co-polymer copolymer by reactor.

Figure 2b is a distribution diagram of the short chain branches (SCB) measured by GPC-IR of the differential composition copolymer for each reactor according to a preferred embodiment of the present invention.

Claims (11)

In the process for producing an ethylene-alphaolefin-diene copolymer using a Ziegler-Natta catalyst system in two series-connected reactors of a first reactor and a second reactor, The ethylene-alphaolefin-diene copolymer includes 50 to 70% by weight of the first component (A) and 30 to 50% by weight of the second component (B) in terms of the overall copolymer composition. A method for producing an ethylene-alpha olefin-diene copolymer for producing a multimodal copolymer having an asymmetric composition having different molecular weights and compositions of components to be polymerized in each reactor so as to be satisfied. (1) MW (A)> MW (B) (2) A1 <(A1 + 2 × B1) / 3 (3) A3> (A3 + 2 × B3) / 3 MW (A): Molecular weight of first reactor production component MW (B): Molecular Weight of Second Reactor Preparation Component A1: Ethylene Content (wt%) of First Reactor Preparation Component B1: Ethylene Content (wt%) of Second Reactor Preparation Component A3: diene content (% by weight) of the first reactor preparation component B3: diene content (% by weight) of the second reactor preparation component (A1 + 2 × B1) / 3: average ethylene content (% by weight) of the entire copolymer (A3 + 2 × B3) / 3: average diene content (% by weight) of the entire copolymer The method of claim 1, A method for producing an ethylene-alphaolefin-diene copolymer in which the ethylene content (A1) of the first reactor production component and the ethylene content (B1) of the second reactor production component satisfy the following formula. (4) 10% by weight ≤ A1-B1 ≤ 20% by weight A1: Ethylene Content (wt%) of First Reactor Preparation Component B1: Ethylene Content (wt%) of Second Reactor Preparation Component The method of claim 1, A method for producing an ethylene-alpha olefin-diene copolymer in which the diene content (A3) of the first reactor component and the diene content (B3) of the second reactor component are satisfied. (5) B3≤A3≤4 × B3 A3: diene content (% by weight) of the first reactor preparation component B3: diene content (% by weight) of the second reactor preparation component The method of claim 1, The first reactor manufacturing component (A) is 50 to 70% by weight of ethylene content (A1), 6 to 10% by weight of diene content (A3) and the remaining content comprises an alpha olefin (A2), The second reactor manufacturing component (B) is 65 to 85% by weight of ethylene content (B1), 1 to 5% by weight of diene content (B3) and the remaining content is an ethylene-alphaolefin-diene ball including alphaolefin (B2) Method of Making Polymers. The method of claim 1, The ethylene-alpha olefin-diene copolymer has an ethylene content of 50 to 80% by weight, a diene content of 3 to 10% by weight and an alpha olefin containing the remaining content of the ethylene-alpha olefin-diene copolymer manufacturing method. The method of claim 1, The ethylene-alpha olefin-diene copolymer has a Mooney viscosity (ML1 + 4, 125 ℃) of 50 to 200 method for producing an ethylene-alpha olefin-diene copolymer. The method of claim 6, The ethylene-alpha olefin diene copolymer has a Mooney viscosity (ML1 + 4, 125 ℃) of 150 to 200 method for producing an ethylene- alpha olefin diene copolymer. The method of claim 5, The ethylene-alpha olefin-diene copolymer is an ethylene-alpha olefin-diene copolymer further comprising 0.001 to 100 phr (part per hundred rubber) of liquid extender oil having a kinematic viscosity of 150 to 200 cSt at 40 ° C. Manufacturing method. An ethylene-alpha olefin-diene copolymer prepared by the process according to any one of claims 1 to 8. A rubber composition comprising the ethylene-alpha olefin-diene copolymer of claim 9, carbon black, process oil, hard coal, silica, a crosslinking agent and a crosslinking accelerator, The rubber composition comprises a total blending amount of 500 to 600 phr of a high filling blend, and the physical properties of the high filling blending rubber containing 0.01 to 20% by weight of the ethylene-alphaolefin-diene copolymer in the total blending amount are as follows. A rubber composition comprising an ethylene-alpha olefin-diene copolymer, characterized by satisfying the range of the compounding strength retention coefficient (CSRC) defined in the range of 0.65 to 1. (6) CSRC = 1-| (Tensile strength change rate according to the change of the total compounding amount) | = 1-| (Tension strength of the compound 1-tensile strength of the compound 2) / (The compounding amount of the compound 1-compounding amount of compound 2) | Tensile strength in the above formula is the result measured in accordance with ASTM D412. The method of claim 10, A rubber composition having a compounding strength retention coefficient (CSRC) of the rubber composition in a range of 0.70 to 1, inclusive.

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