KR20160064819A - Method for preparing branched diene based polymer and branched diene based polymer prepared using the same - Google Patents

Abstract

The present invention provides a method of preparing a diene-based polymer including the following steps: polymerizing a diene monomer in a non-polar solvent in the presence of a polymerization catalyst, represented by chemical formula 1, including a neodymium compound, a halogen compound, and an alkylating agent to prepare a polymer; and making the polymer to react with a radical initiator, wherein an alkylating agent is used up to a content of 10 equivalent with respect to the neodymium compound of 1 equivalent and to a diene-based polymer prepared thereby and having a narrow molecular weight distribution and high branch degree. In chemical formula 1, R1 to R3 are as defined in the specification.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a diene-based polymer, and a diene-based polymer prepared by using the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a process for producing a diene polymer having a narrow molecular weight distribution and exhibiting excellent physical properties, and a diene polymer produced by using the process.

As the demand for rubber increases in various manufacturing fields such as tires, impact polystyrene, shoe soles, and golf balls, the value of polybutadiene rubber, an intermediary of petrochemical products, is increasing as a substitute for natural rubber, which lacks production.

Butadiene polymers such as polybutadiene rubber are known as thermally and mechanically excellent rubbers and are widely used in various fields. Particularly, since the more the cis-1,4-bond content in the butadiene monomer unit is, the more excellent mechanical properties can be exhibited, a great deal of research has been conducted on a method for producing a butadiene polymer having a high cis- have.

Specifically, a method for producing a butadiene-based polymer by using a rare earth metal compound such as neodymium and a polymerization catalyst of a complex metal consisting of an alkylating agent of Group I to Group III, specifically methylaluminoxane has been developed. However, the polymer obtainable by the above method has a problem that the cis-1,4 bond content is not sufficiently high and the vinyl content is not sufficiently low, so that the physical properties are still insufficient.

Alternatively, a polymerization catalyst comprising a rare earth metal compound, an alkylating agent of Group I to Group III, and an ionic compound consisting of a non-coordinating anion and a cation is used to prepare a butadiene-based polymer having a high cis- Was developed. However, the above method uses Nd (OCOCCl ₃ ) ₃ as a rare earth metal compound, but since the polymerization activity of the compound is low and the vinyl bond content of the butadiene polymer is large, the content of the butadiene- The rubber composition has insufficient improvement in physical properties as compared with the rubber composition containing the conventional butadiene polymer. In the case of the butadiene polymer produced by the above method, the lower the vinyl bond content, the wider the molecular weight distribution is, and it is difficult to obtain the butadiene polymer having a sufficiently low vinyl bond content and a molecular weight distribution within a specific range.

As another method, there has been developed a method for producing a butadiene polymer having a high cis-1,4 bond content by using a polymerization catalyst comprising a rare earth metal salt composed of a halogen atom-containing component and aluminoxane. However, this method also has a problem that since the specific catalyst such as neodymium salt of bis (trichloroacetic acid) (bersatanic acid) is used, the polymerization activity of the neodymium salt is low and the industrial property is low.

On the other hand, neodymium-catalyzed polybutadiene (Nd-BR) has superior characteristics in terms of running resistance, abrasion resistance and rebound resilience, compared with a high proportion of cis-polybutadiene. In addition, the linear Nd-BR exhibits improved dynamic properties and a low energy absorption rate, which reduces running resistance in the tire field and improves rebound resilience in golf ball applications. However, since the linear rubber has a high solution viscosity, the processability is lowered, and the dissolution rate is slow, and the practicality is low from the viewpoint of economy.

Branching is particularly important for the processability of the polymer. Specifically, the branching affects the dissolution rate and viscosity characteristics of the polymer, which affects the processability of the polymer. In addition, in the case of a branched polymer, the molecular weight distribution is widened, which may result in deterioration of physical properties. Thus, the polymers produced prior to the branching reaction, specifically the radical initiator reaction step, must have a very narrow molecular weight distribution, which is also a low state of the short chain polymer, so that a short chain branch ) Can be minimized.

Japanese Patent Laid-Open No. 2001-048940

A first object of the present invention is to provide a diene polymer having a narrow molecular weight distribution along with a high degree of branching and capable of improving the physical properties when applied to a rubber composition and minimizing energy loss And a method for manufacturing the same.

A second technical object of the present invention is to provide a diene polymer produced by the above production process.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to one embodiment of the present invention, there is provided a process for preparing a polymer by reacting a diene monomer in a nonpolar solvent in the presence of a polymerization catalyst comprising a neodymium compound represented by the following formula (1), an alkylating agent and a halogen compound And reacting the polymer with a radical initiator, wherein the alkylating agent is used in an amount of 10 equivalents or less based on 1 equivalent of the neodymium compound.

[Chemical Formula 1]

In Formula 1,

R ₁ is a linear or branched alkyl group having 6 to 12 carbon atoms,

R ₂ and R ₃ are each independently a hydrogen atom or a linear or branched alkyl group having from 2 to 8 carbon atoms, provided that R ₂ and R ₃ are not hydrogen atoms at the same time.

According to another embodiment of the present invention, there is provided a diene polymer produced by the above production method.

Other details of the embodiments of the present invention are included in the following detailed description.

In the production of the diene-based polymer by the production process of the present invention, it is possible to minimize the short-chain branch after branching. In addition, the diene polymer to be produced has a narrow molecular weight distribution while having a high degree of branching, thereby improving the physical properties of the rubber composition when applied to the rubber composition, and minimizing energy loss.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Dien series  Method of producing polymer

A method for producing a diene polymer according to an embodiment of the present invention comprises polymerizing a diene monomer in a non-polar solvent in the presence of a polymerization catalyst comprising a neodymium compound represented by the following formula (1), an alkylating agent and a halogen compound (Step 1), and reacting the polymer with a radical initiator (step 2), wherein the alkylating agent is used in an amount of 10 equivalents or less based on 1 equivalent of the neodymium compound:

[Chemical Formula 1]

In Formula 1,

R ₁ is a linear or branched alkyl group having 6 to 12 carbon atoms,

R ₂ and R ₃ are each independently a hydrogen atom or a linear or branched alkyl group having from 2 to 8 carbon atoms, provided that R ₂ and R ₃ are not hydrogen atoms at the same time.

More specifically, in Formula 1, R ₁ is a linear or branched alkyl group having 6 to 8 carbon atoms, R ₂ and R ₃ are each independently a hydrogen atom, or a linear or branched alkyl group having 2 to 6 carbon atoms Wherein R ₂ and R ₃ are not hydrogen atoms at the same time.

Each step is described in detail below

(Step 1)

Step 1 for producing a branched diene polymer according to an embodiment of the present invention is a step of polymerizing a diene monomer in a nonpolar solvent in the presence of a polymerization catalyst to produce a polymer.

In the step 1, the catalyst for polymerization includes a neodymium compound, an alkylating agent, and a halogen compound of Formula 1.

As the neodymium compound used as a catalyst in the conventional diene polymerization process, Nd (neodecanoate) ₃ compound containing a carboxylate ligand in which two methyl groups are substituted at the? -Position was used. However, in the case of the Nd (neodecanoate) ₃ compound, the Nd (neodecanoate) ₃ compound is present in a large amount in the form of an oligomer such as the following formula (2) at the time of polymerization and causes a decrease in efficiency of conversion to a catalytically active species, There is a disadvantage.

(2)

On the contrary, the neodymium compound of Formula 1 used in the present invention contains a carboxylate ligand containing a variety of alkyl groups as substituents in the α-position instead of the conventional neodecanoate group as a ligand, The change is prevented by the entanglement between the compounds and there is no fear of oligomerization. In addition, the neodymium compound of Formula 1 has a high solubility in a polymerization solvent and has a low neodymium ratio in a central portion, which is difficult to convert to a catalytically active species, and thus has a high conversion ratio to a catalytically active species.

Specifically, the neodymium compound of Formula 1 may be at least one selected from the group consisting of Nd (2,2-diethyldecanoate) ₃ , Nd (2,2-dipropyldecanoate) ₃ , Nd (2,2-dibutyldecanoate) _3, Nd (2,2- di-hexyl decanoate) _3, Nd (2,2- dioctyl decanoate) _3, Nd (2- ethyl-2-propyl decanoate) _3, Nd (2- ethyl 2-butyl decanoate) _3, Nd (2- ethyl-2-hexyl decanoate) _3, Nd (2- butyl-2-propyl decanoate) _3, Nd (2- propyl-2-hexyl de decanoate) _3, Nd (2- propyl-2-isopropyl decanoate) _3, Nd (2- butyl-2-hexyl decanoate) _3, Nd (2- cyclohexyl-2-octyl decanoate) ₃ , Nd (2-t- butyl decanoate) _3, Nd (2,2- diethyl octanoate) _3, Nd (2,2- dipropyl octanoate) _3, Nd (2,2- dibutyl octanoate) _3, Nd (2,2- dihexyl octanoate) _3, Nd (2- ethyl-2-propyl-octanoate) _3, Nd (2- ethyl-hexyl-2-octanoate) _3, Nd (2,2-diethyl nonanoate) ₃ , Nd (2,2- Dipropyl no nano-benzoate) _3, Nd (2,2- dibutyl no nano-benzoate) _3, Nd (2,2- dihexyl no nano-benzoate) _3, Nd (2- ethyl-2-propyl-no nano-benzoate) ₃ Or Nd (2-ethyl-2-hexylnonanoate) ₃ , and any one or a mixture of two or more thereof may be used. More particularly the neodymium compounds are Nd (2,2- diethyl decanoate) _3, Nd (2,2- dipropyl decanoate) _3, Nd (2,2- di-butyl decanoate) _3, Nd (2,2-dihexyldecanoate) ₃ , and Nd (2,2-dioctyldecanoate) ₃ , or a mixture of two or more thereof.

The neodymium compound of Formula 1 may have a weight average molecular weight (Mw) of 800 to 1400 g / mol. When the weight average molecular weight is within the above-mentioned range, more excellent catalytic activity can be exhibited.

The solubility of the neodymium compound of Formula 1 may be about 4 g or more per 6 g of non-polar solvent at room temperature (25 ° C). In the present invention, the solubility of the neodymium compound means a degree of dissolution without cloudiness. By exhibiting such high solubility, excellent catalytic activity can be exhibited.

In addition, the neodymium compound of Formula 1 may exhibit catalyst activity of 600 kg [polymer] / mol [Nd] · h or more over a polymerization time of 30 minutes. In the present invention, the catalytic activity is a value obtained from the molar ratio of the neodithium compound introduced in the formula (1) to the total amount of the produced diene polymer.

The neodymium compound of the formula (1) may be used in an amount of 0.1 to 0.5 mmol, more specifically 0.1 to 0.3 mmol, per 100 g of the diene monomer. If the amount of the neodithium compound of Formula 1 is less than 0.1 mmol, the catalytic activity for polymerization is low. If the amount of neodithium compound exceeds 0.5 mmol, the catalyst concentration becomes too high, and a demineralization process is required.

In the above catalyst for polymerization, the alkylating agent is an organometallic compound capable of transferring a hydrocarbyl group to another metal, and serves as a cocatalyst. The alkylating agent is not particularly limited as long as it is used as an alkylating agent in the production of a diene-based polymer. Specifically, the alkylating agent may be an organometallic compound soluble in a non-polar solvent such as an organoaluminum compound and containing a metal-carbon bond.

More specifically, the organoaluminum compounds include diethylaluminum hydride, di-n-propylaluminum hydride, diisopropylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride (DIBAH) Di-n-octylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride, phenylethylaluminum hydride, phenyl-n-propylaluminum hydride, phenylisopropylaluminum N-butyl aluminum hydride, phenyl isobutyl aluminum hydride, phenyl-n-octyl aluminum hydride, p-tolylethyl aluminum hydride, p-tolyl-n-propyl aluminum hydride, p- Isopropyl aluminum hydride, p-tolyl-n-butyl aluminum hydride, p-tolyl iso N-butyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl isobutyl aluminum hydride, benzyl isobutyl aluminum hydride, Dihydrocarbylaluminum hydride such as aluminum hydride or benzyl-n-octylaluminum hydrogen; Hydrocarbylaluminum such as ethylaluminum dihydride, n-propylaluminum dihydride, isopropylaluminum dihydride, n-butylaluminum dihydride, isobutylaluminum dihydride or n-octylaluminum dihydride, Dihydride and the like.

More specifically, the alkylating agent may be DIBAH, wherein the DIBAH may serve as a molecular weight regulator during polymerization.

In general, alkyl alumoxane such as methylalumineoxane (MAO) is mainly used in order to obtain a narrow molecular weight distribution in the production of a diene polymer. In contrast, the present invention maximizes the chain growth reaction by increasing the amount of the neodymium compound of Formula 1 as the main catalyst, while minimizing the chain transfer reaction by reducing the amount of the alkylating agent used as the cocatalyst , It is possible to produce a diene polymer having a narrow molecular weight distribution without using alkylaluminoxane.

Specifically, the neodymium compound of Formula 1 and the alkylating agent are added in order to make the finally produced diene polymer have a narrow molecular weight distribution (Mw / Mn, MWD), more specifically, a molecular weight distribution of 2 to 2.5, It should be used at an optimized content ratio. Specifically, the alkylating agent may be used in an amount of 10 equivalents or less, more specifically 4 to 8 equivalents based on 1 equivalent of the neodymium compound of Formula 1. When the content is out of the above range, it is difficult to prepare a diene polymer having the above molecular weight distribution.

In the above-mentioned catalyst for polymerization, the kind of the halogen compound is not particularly limited, but can be used without particular limitation, as long as it is generally used as a halogenating agent in the production of a diene-based polymer. Specifically, the halogen compound may be an aluminum halogen compound or an inorganic halogen compound in which aluminum is substituted with boron, silicon, tin or titanium in the aluminum halogen compound, or an organic halogen compound such as a t-alkylhalogen compound (alkyl having 4 to 20 carbon atoms) Halogen compounds.

More specifically, examples of the inorganic halogen compound include dimethylaluminum chloride, diethylaluminum chloride (DEAC), dimethylaluminum bromide, diethylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, methylaluminum dichloride, ethylaluminum dichloride , Methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, methylmagnesium chloride, methylmagnesium bromide, Methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesium chloride, butylmagnesium bromide, phenylmagnesium chloride, phenylmagnesium bromide, Di-t-butyl tin dichloride, di-t-butyl tin dibromide, dibutyl tin dichloride, dibutyl tin dichloride, dibutyl tin dichloride, dibutyl tin dichloride, dibutyl tin dichloride, dibutyl tin dichloride, dibutyl tin dichloride, Tin dibromide, tributyltin chloride, tributyltin bromide, and the like.

Examples of the organic halogen compound include t-butyl chloride, t-butyl bromide, allyl chloride, allyl bromide, benzyl chloride, benzyl bromide, chloro- di- phenyl methane, There may be mentioned triphenylmethylbromide, benzylidene chloride, benzylidene bromide, methyltrichlorosilane, phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, benzoyl chloride, benzoyl bromide, propionyl chloride, propionyl bromide, Methyl chloroformate, methyl bromoformate, and the like.

Any one or a mixture of two or more of the above-mentioned inorganic halogen compounds and organic halogen compounds may be used.

The halogen compound may be used in an amount of 1 to 20 equivalents, more preferably 1 to 5 equivalents, and more preferably 2 to 3 equivalents based on 1 equivalent of the neodymium compound of the formula (1).

The catalyst for polymerization may further include a diene-based monomer.

As described above, a part of the diene-based monomer used in the present polymerization reaction is preliminarily mixed with the polymerization catalyst and used in the form of a preforming catalyst, whereby the activity of the catalyst can be improved, .

Specific examples of the diene monomer include 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, Butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene or 2,4-hexadiene. Any one or a mixture of two or more may be used.

The diene monomer which can be used in the production of the polymerization catalyst may be used in an amount within a range of the total amount of the diene monomer used in the polymerization reaction. Specifically, 1 equivalent of the neodymium compound of the formula To 50 equivalents, more specifically 20 to 40 equivalents, and even more specifically 25 to 35 equivalents.

The catalyst for polymerization may be prepared by sequentially charging a neodymium compound of Formula 1, an alkylating agent, a halogen compound, and optionally a diene monomer into the nonpolar solvent.

The nonpolar solvent is a nonpolar solvent that is not reactive with the above-mentioned catalyst components, specifically, an aliphatic hydrocarbon solvent such as pentane, hexane, isopentane, heptane, octane, isooctane and the like; Cyclic aliphatic hydrocarbon solvents such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane and the like; Or an aromatic hydrocarbon solvent such as benzene, toluene, ethylbenzene, xylene, etc., and any one or a mixture of two or more of them may be used. More specifically, the nonpolar solvent may be hexane.

Further, in order to improve the polymerization activity and to shorten the induction period of the polymerization initiation, it is also possible to selectively carry out a step of mixing and reacting the above components in advance, followed by aging. At this time, the aging temperature may be 0 to 100 캜, more specifically 20 to 80 캜. If the aging temperature is only 0 占 폚, aging is not sufficient, and if it exceeds 100 占 폚, the catalytic activity may decrease.

On the other hand, the polymerization reaction may be carried out by radical polymerization. Specifically, it may be bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization, and more specifically, solution polymerization.

More specifically, the polymerization reaction may be carried out by charging the diene monomer into the polymerization catalyst in a non-polar solvent and reacting.

Specific examples of the diene monomer include 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, Methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, or 2,4-hexadiene, and any one of them or Two or more mixtures may be used. More specifically, the diene-based monomer may be 1,3-butadiene.

In addition, a reaction terminator for completing the polymerization reaction such as polyoxyethylene glycol phosphate or the like during the polymerization reaction; Or antioxidants such as 2,6-di-t-butyl paracresol and the like may further be used. In addition, additives such as a solvent, a chelating agent, a dispersing agent, a pH adjusting agent, an oxygen scavenger, and an oxygen scavenger may be further optionally added to the solution.

The polymerization reaction may be carried out at a temperature of 20 to 200 ° C, more specifically 20 to 70 ° C, for 15 minutes to 3 hours, more specifically 30 minutes to 3 hours. If the temperature during the polymerization reaction exceeds 200 ° C, it is difficult to sufficiently control the polymerization reaction, and the content of cis-1,4 bond in the resultant diene polymer may be lowered. If the temperature is lower than 20 캜, the polymerization reaction rate and efficiency may be lowered.

As a result of the polymerization reaction, a neodymium-catalyzed diene polymer containing an active organometallic moiety derived from a catalyst comprising the neodymium compound of Formula 1, more specifically, a neodymium-catalyzed diene polymer containing 1,3-butadiene monomer units Butadiene-based polymer is produced.

The prepared neodymium-catalyzed diene-based polymer may have pseudo-living properties. Accordingly, prior to the execution of the subsequent step 2 process, a step of functionalizing the produced neodymium-catalyzed diene-based polymer may optionally be further carried out.

Specifically, the neodymium-catalyzed diene polymer is reacted with the active organometallic moiety in a diene polymer containing an active organometallic moiety to treat a terminal modifier that modifies the terminal of the diene polymer, Can be modified with a functional group having an interaction with an inorganic filler such as carbon black or silica. The terminal modifier may increase the molecular weight by adding the functional group to the polymer or by coupling when reacting with the diene polymer.

Specifically, the terminal modifier may be at least one selected from the group consisting of azacyclopropane, ketone, carboxyl, thiocarboxyl, carbonate, carboxylic anhydride, carboxylate, At least one functional group selected from the group consisting of an isocyanate group, a halogenated isocyanate group, an epoxy group, a thioepoxy group, an imine group and an MZ bond (wherein M is selected from the group consisting of Sn, Si, Ge and P and Z is a halogen atom) And does not contain active proton and onium salts which inactivate the active organometallic moiety.

More specifically, the termination modifier is selected from the group consisting of alkoxysilanes, imine-containing compounds, esters, ester-carboxylate metal complexes, alkyl ester carboxylate metal complexes, aldehydes or ketones, amides, isocyanates, isothiocyanates, Or a mixture of two or more thereof.

The terminal modifier may be used in an amount of 0.01 to 200 equivalents, more specifically 0.1 to 150 equivalents, based on 1 equivalent of the neodymium compound of the formula (1).

(Step 2)

Step 2 for producing a branched branched diene polymer according to an embodiment of the present invention is a step for producing a branched diene polymer by reacting the polymer prepared in Step 1 with a radical initiator.

The radical initiator is a compound that can be activated to provide a free radical, which promotes polymerization of the vinyl aromatic monomer.

Specifically, the radical initiator is selected from the group consisting of tert-butyl peroxyacetate, dibenzoyl peroxide, dilauryl peroxide, t-butyl hydroperoxide, ditert-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, , Tert-butyl peroxybenzoate, 1,1-bis (t-butylperoxy) cyclohexane, benzoyl peroxide, Peroxides such as succinoyl peroxide or t-butyl peroxy pivalate; Or an azo-based compound such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, azobismethylisoleate or azobiscyano valerate, and the like. Any one or a mixture of two or more of them may be used.

The radical initiator may be used in an amount less than the amount by which the polymer produced in step 1 is gelled, and more specifically from 10 to 90 wt%, more preferably from 40 to 70 wt%, based on the total weight of the polymer prepared in step 1 % ≪ / RTI > by weight.

The radical initiator may be added at a polymerization conversion of 80% or more, more specifically 80 to 95%.

In addition, the polymer and the radical initiator may be contacted by mixing or compounding. The mixing or compounding can be carried out according to a conventional method, specifically, by using a mixing apparatus such as a continuous stirring tank reactor.

By the reaction of the polymer and the radical initiator, a highly branched diene polymer is prepared.

Further, the production method according to an embodiment of the present invention may further include a step of hydrogenating the branched polymer.

Specifically, the hydrogenation can be carried out by treating the branched diene polymer with a homogeneous or heterogeneous transition metal catalyst or a diimide compound such as hydrazine. have.

The degree of hydrogenation can be expressed as a percentage of the amount of double bonds remaining in the polymer after hydrogenation. Specifically, the hydrogenation may be carried out at 10%, more particularly 30%.

After completion of the reaction, the resulting polymer can be obtained by precipitating a lower alcohol such as methyl alcohol, ethyl alcohol, or steam. Accordingly, the method for preparing a diene-based polymer according to an embodiment of the present invention may further include a step of precipitation and separation of the produced diene-based polymer.

The filtration, separation and drying of the precipitated diene polymer may be carried out according to a conventional method.

As described above, the method for producing a diene-based polymer according to an embodiment of the present invention is characterized in that the neodymium compound of Formula 1 having excellent catalytic activity is used at an optimized content ratio with an alkylating agent as a cocatalyst, Chain branch after branching can be minimized and the diene polymer finally produced can have a molecular weight distribution narrowing to a high degree of branching to improve the physical properties of the rubber composition and minimize energy loss.

Dien series  polymer

According to another embodiment of the present invention, there is provided a diene polymer produced by the above production method.

Specifically, the diene-based polymer is a diene-based polymer containing an active organometallic moiety derived from a catalyst containing the neodymium compound of Formula 1, more specifically, a neodymium-catalyzed butadiene containing 1,3-butadiene monomer units Based polymer.

Also, the diene polymer may contain 80 to 100% by weight of 1,3-butadiene monomer units and optionally 20% by weight or less of other monomer units copolymerizable with 1,3-butadiene. If the 1,3-butadiene monomer unit content in the diene polymer is less than 80% by weight, the 1,4-cis content of the polymer may be lowered.

In addition, the diene polymer may be polybutadiene comprising only 1,3-butadiene monomer.

The diene polymer may have a narrow molecular weight distribution (MWD), specifically 2 to 2.9, more specifically 2.2 to 2.4, by a specific production method. If the molecular weight distribution of the diene polymer is less than 2, the workability of the rubber composition containing the diene polymer tends to deteriorate, and it is difficult to sufficiently improve the physical properties of the rubber composition, and if the molecular weight distribution of the diene polymer exceeds 2.9, There is a possibility that the physical properties of the rubber such as hysteresis loss of the composition may be deteriorated.

In addition, the diene polymer may have a branch index of 0.2 or more, specifically 0.2 to 0.3. In the present invention, the degree of branching of the polymer was determined by dissolving the prepared polymer in toluene at a concentration of 5% by weight, and then measuring the solution viscosity measured with a Brookfield viscometer at spindle # 3 at a rate of 50 rpm Value is corrected by dividing by the Mooney viscosity, and the higher the branching degree value, the more the branching in the polymer is contained.

The diene polymer preferably has a cis content of the diene polymer measured by Fourier transform infrared spectroscopy, specifically, a cis-1,4-bond content of 95% or more, more specifically 95 to 98% . Since the cis-1,4 bond content in the 1,3-butadiene monomer unit is larger than that of the conventional butadiene polymer and the vinyl bond content is low, the extensibility of the rubber composition is remarkably high and the abrasion resistance , Crack resistance and ozone resistance can be improved.

The weight average molecular weight (Mw) of the diene polymer may be 5.8 × 10 ⁵ g / mol to 9 × 10 ⁵ g / mol, more specifically ⁶ × 10 ⁵ g / mol to 7.0 × 10 ⁵ g / mol. In the present invention, the weight average molecular weight is a polystyrene reduced molecular weight analyzed by gel permeation chromatography (GPC). When the weight average molecular weight of the butadiene polymer is less than 580,000 g / mol, the elastic modulus of the vulcanized product is lowered, hysteresis loss increases, and the abrasion resistance further deteriorates. When the weight average molecular weight exceeds 700,000 g / mol, the butadiene polymer The workability of the rubber composition containing it is deteriorated and the kneading of the kneaded mixture becomes difficult and the physical properties of the rubber composition can not be sufficiently improved.

The diene polymer may have a Mooney viscosity (MV) at 100 ° C of 30 to 50, more specifically 35 to 45.

The diene polymer may be modified by a modifier such that the terminal of the polymer is modified to a functional group having an interaction with an inorganic filler such as carbon black or silica.

Specifically, the functional group may be selected from the group consisting of an azacyclopropane group, a ketone group, a carboxyl group, a thiocarboxyl group, a carbonate, a carboxylic anhydride, a metal carboxylate, an acid halide, a urea, a thiourea, an amide group, a thioamide group, A halogenated isocyanato group, an epoxy group, a thioepoxy group, an imine group and an MZ bond (provided that M is selected from the group consisting of Sn, Si, Ge and P, and Z is a halogen atom).

Rubber composition

According to another embodiment of the present invention, there is provided a rubber composition comprising the diene polymer.

Specifically, the rubber composition may include 10 wt% to 100 wt% of the diene polymer and 90 wt% or less of the rubber component. If the content of the diene polymer is less than 10% by weight, the abrasion resistance, crack resistance and ozone resistance improving effect of the rubber composition may be insignificant.

The rubber component is specifically a natural rubber (NR); (Ethylene-co-butadiene copolymer), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene- (Styrene-co-butadiene), poly (styrene-co-butadiene), poly (styrene-co-butadiene) Propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber and the like, and any one or a mixture of two or more thereof may be used.

The rubber composition may further include at least 10 parts by weight of a filler based on 100 parts by weight of the rubber component. The filler may be carbon black or silica, and any one or a mixture of two or more thereof may be used.

In addition to the above rubber components and fillers, a compounding agent commonly used in the rubber industry such as a vulcanizing agent, a vulcanization accelerator, an antioxidant, an anti-scorch agent, a softener, zinc oxide, stearic acid or a silane coupling agent, It can be appropriately selected and compounded within a range that does not inhibit.

Such rubber compositions are useful in the manufacture of various rubber molded articles such as O-rings, profiles, gaskets, membranes, tires, tire treads, side walls, braking members or hoses.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

( Example  One) Dien series  Preparation of polymer

The neodymium compound of the following formula (1a), diisobutylaluminum hydride (DIBAH), diethylaluminum chloride (DEAC) and 1,3-butadiene were added in an equivalent ratio of 1: 8: 2.4: Catalyst.

Under nitrogen, 2086 g of a hexane solution of 1,3-butadiene in an amount of 20 g was added to an 8 L high-pressure reactor, and the temperature was raised to 70 DEG C. The polymerization catalyst prepared above was added to the high-pressure reactor, and polymerization was carried out at 70 DEG C for 60 minutes . When polymerization conversion was 98%, azobisisobutyronitrile (AIBN) was added and further polymerization reaction was carried out. After completion of the reaction, a part of the reaction solution was taken and the conversion was measured. The Mooney viscosity (MV), the weight average molecular weight (Mw), the molecular weight distribution (MWD), and the cis content were measured for the diene polymer obtained as a result of the polymerization reaction, Respectively.

(1a)

(1a)

( Comparative Example  1 to 3) Dien series  Preparation of polymer

Polymerization was carried out in the same manner as in Example 1, except that, as shown in Table 1 below.

After completion of the reaction, a part of the reaction solution was taken to measure the conversion. The content of MV, Mw, MWD and Cis-1,4 bond of the diene polymer prepared in the same manner as in Example 1 was measured, Respectively.

Nd ^{1 )}
(mmol / BD 100g) pBD ^{2 )} (eq.) DIBAH ^{3 )}
(eq.) DEAC ⁴⁾ (eq.) AIBN
(mmol / BD 100g) Polymerization temperature (캜) Polymerization time (minutes) Conversion Rate (%) MV Mw
(X10 ⁵ g / mol) MWD Content of Cis 1,4 bond (%) Branching degree
(SV / MV) Example 1 0.25 33 8.0 2.4 2.5 70 60 100 38.1 6.16 2.3 97.7 0.236 Comparative Example 1 0.2 33 10.2 2.4 2.0 70 60 95 41.7 7.18 3.0 96.8 0.190 Comparative Example 2 0.17 33 12.5 2.4 1.7 70 60 94.1 42.9 8.24 3.3 96.3 0.153 Comparative Example 3 0.15 33 17.0 2.4 1.5 70 60 68.3 33.1 5.01 4.4 96.9 0.170 Comparative Example 4 0.25 33 8.0 2.4 - 70 60 100 38.1 6.16 2.3 97.3 0.157

In Table 1, 1) Nd means the content of the neodymium compound of Formula 1a as the main catalyst, and the content of pBD, DIBAH and DEAC in 2) to 4) is the value based on 1 equivalent of the neodymium compound of Formula 1a to be. In Table 1, abbreviation pBD stands for 1,3-butadiene, DIBAH stands for diisobutylaluminum hydride, and DEAC stands for diethylaluminum chloride.

As shown in Table 1, the polymer of Example 1 produced by the production method according to the present invention exhibited a remarkably narrow molecular weight distribution as compared with Comparative Examples 1 to 3 in which the mixing ratio of the neodymium compound and the alkylating agent exceeded 10 equivalents . In addition, the polymer of Example 1 exhibited the same level of molecular weight distribution as that of Comparative Example 4 in which no radical initiator was added, but the degree of branching was much higher. From this, it can be seen that the polymer of Example 1 produced by the production method according to the present invention has a short molecular chain branching after branching with the use of a radical initiator and has a narrow molecular weight distribution with a high degree of branching have.

From this, it can be seen that the molecular weight distribution and branching degree of the diene polymer can be controlled according to the content ratio of the neodymium compound and the alkylating agent in the polymerization catalyst, and the amount of the radical initiator added.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And falls within the scope of the invention.

Claims (20)

A process for preparing a polymer by polymerizing a diene monomer in a nonpolar solvent in the presence of a polymerization catalyst comprising a neodymium compound represented by the following formula (1), an alkylating agent and a halogen compound, and
Reacting the polymer with a radical initiator,
Wherein the alkylating agent is used in an amount of 10 equivalents or less based on 1 equivalent of the neodymium compound.
[Chemical Formula 1]

In Formula 1,
R ₁ is a linear or branched alkyl group having 6 to 12 carbon atoms,
R ₂ and R ₃ are each independently a hydrogen atom or a linear or branched alkyl group having from 2 to 8 carbon atoms, provided that R ₂ and R ₃ are not hydrogen atoms at the same time.
The method according to claim 1,
Is the Neodymium compound Nd (2,2- diethyl decanoate) _3, Nd (2,2- dipropyl decanoate) _3, Nd (2,2- di-butyl decanoate) _3, Nd (2, 2-di-hexyl decanoate) _3, Nd (2,2- dioctyl decanoate) _3, Nd (2-ethyl-2-propyl decanoate) _3, Nd (2-ethyl-2-butyl to Kano Eight) _3, Nd (2- ethyl-2-hexyl decanoate) _3, Nd (2- butyl-2-propyl decanoate) _3, Nd (2- propyl-2-hexyl decanoate) _3, Nd (2-propyl-2-isopropyl decanoate) _3, Nd (2-butyl-2-hexyl decanoate) _3, Nd (2-hexyl-2-octyl decanoate) _3, Nd (2-t -butyl decanoate) _3, Nd (2,2- diethyl octanoate) _3, Nd (2,2- dipropyl octanoate) _3, Nd (2,2- dibutyltin octanoate) _3, Nd (2,2- dihexyl octanoate) _3, Nd (2- ethyl-2-propyl-octanoate) _3, Nd (2- ethyl-hexyl-2-octanoate) _3, Nd (2,2- Diethylnonanoate) ₃ , Nd (2,2-dipropylnonanoate) _3, Nd (2,2- dibutyl no nano-benzoate) _3, Nd (2,2- dihexyl no nano-benzoate) _3, Nd (2- ethyl-2-propyl-no nano-benzoate) ₃ and Nd (2- ethyl 2-hexylnonanoate). _{3. The} process for producing a diene-based polymer according to claim 1,
The method according to claim 1,
Wherein the neodymium compound is used in an amount of 0.1 to 0.5 mmol per 100 g of the diene monomer.
The method according to claim 1,
Wherein the alkylating agent is an alkylaluminum compound.
The method according to claim 1,
Wherein the alkylating agent is diisobutyl aluminum hydride.
The method according to claim 1,
Wherein the alkylating agent is used in an amount of 2 to 8 equivalents based on 1 equivalent of the neodymium compound.
The method according to claim 1,
Wherein the halogen compound comprises any one or a mixture of two or more selected from the group consisting of an inorganic halogen compound containing at least one element selected from the group consisting of aluminum, boron, silicon, tin and titanium, and an organic halogen compound A method for producing a diene-based polymer.
The method according to claim 1,
Wherein the halogen compound is diethylaluminum chloride.
The method according to claim 1,
Wherein the halogen compound is used in an amount of 1 to 20 equivalents based on 1 equivalent of the neodymium compound.
The method according to claim 1,
Wherein the polymerization catalyst further comprises a diene monomer.
11. The method of claim 10,
Wherein the diene monomer is contained in an amount of 1 to 50 equivalents based on 1 equivalent of the neodymium compound.
The method according to claim 1,
Wherein the diene-based monomer is at least one selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, At least one member selected from the group consisting of methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl- ≪ / RTI &
The method according to claim 1,
Wherein the radical initiator is any one or a mixture of two or more selected from the group consisting of a peroxide compound and an azo compound.
The method according to claim 1,
Wherein the radical initiator is selected from the group consisting of tert-butyl peroxyacetate, dibenzoyl peroxide, dilauryl peroxide, tert-butyl hydroperoxide, ditert-butyl peroxide, cumene hydroperoxide, dicumyl peroxide, (Tert-butylperoxy) -3,3,5-trimethyl-cyclohexane, tert-butyl peroxybenzoate, 1,1-bis (t- butylperoxy) cyclohexane, benzoyl peroxide, Butyl peroxypivalate and azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, azobismethylisoleate and azo compounds such as azobisisobutyronitrile, Biscyanobalate, and mixtures thereof. 2. The process for producing a diene-based polymer according to claim 1,
The method according to claim 1,
Wherein the radical initiator is used in an amount of 10 to 90% by weight based on the total weight of the polymer.
A diene-based polymer produced by the process according to claim 1.
17. The method of claim 16,
Having a molecular weight distribution (Mw / Mn) of 2 to 2.8, a degree of branching (SV / MV) of 0.2 or more, and a content of cis 1,4 bond in the diene polymer measured by Fourier transform infrared spectroscopy is 95% polymer.
17. The method of claim 16,
Wherein the weight average molecular weight (Mw) is 5.8 × 10 ⁵ g / mol to 9 × 10 ⁵ g / mol and the Mooney viscosity at 100 ° C. is 30 to 50.
17. The method of claim 16,
Butadiene monomer unit. The diene-based polymer is a butadiene-based polymer containing 1,3-butadiene monomer units.
A rubber composition comprising the diene polymer according to claim 16.