KR19980017267A - Method for producing polypropylene elastomer - Google Patents

Abstract

The present invention relates to a method for producing a polypropylene elastic body, an object of the present invention is to provide a polypropylene with improved elasticity in a state that is excellent in stereoregularity and crystallinity is not accompanied by a drop in physical properties such as mechanical strength.

The present invention relates to 0.1-50 mole of metallocene catalyst which is a transition metal organic compound of Group IVB of periodic table per mole of Ziegler-Natta catalyst composed of transition metal of Group IVB of Periodic Table and halogen element during polymerization. A mixed catalyst made of% is added, and propylene and 1-butene are used as monomers constituting the polypropylene elastomer.

The polypropylene elastomer according to the method of the present invention can be molded into various products such as plates, films, containers, fibers, and the like.

Description

Method for producing polypropylene elastomer

The present invention relates to a method for producing a polypropylene elastomer, and more particularly, by synthesizing a polypropylene-polybutene copolymer using a mixed catalyst of a metallocene catalyst and a Ziegler-Natta catalyst, high crystallinity and high stereoregularity The present invention relates to a method for producing a polypropylene elastomer having improved elasticity.

Polypropylene is a general-purpose plastic with high strength and excellent mechanical properties, but its low elasticity has limitations in the field of application. In order to compensate for this, polypropylene is mixed with an olefin rubber resin or a polypropylene-polyethylene copolymer is prepared. However, the polypropylene / olefin rubber mixture or polypropylene-polyethylene copolymer produced at this time has the disadvantage of low physical properties due to low stereoregularity and crystallinity, and is formed by forming a relatively large spherulite. The commodity generally has a low transparency, thus degrading its commercial value. Therefore, there is a need for a method of manufacturing a polypropylene elastic body that can have elasticity in a state where the mechanical properties of the polypropylene are not accompanied by a decrease.

In order to improve the elasticity of polypropylene, a method of mixing an elastic olefin rubber resin with polypropylene or a method for producing a polypropylene-polyethylene copolymer has been proposed.

Normally, a mixture of polypropylene olefin rubber or a polypropylene-polyethylene copolymer is known to have higher elasticity than polypropylene.

For example, Japanese Patent Laid-Open Nos. 55-118909 and 55-118910 disclose that polypropylene-polyethylene copolymers are synthesized to improve elasticity, and Japanese Patent Laid-Open No. 54-022453 describes polypropylene-polyethylene-polybutene Although it is described to improve the elasticity by synthesizing the copolymer, the resulting copolymer has a disadvantage that the stereoregularity is low and the crystallinity is lowered and the mechanical strength is lowered. In addition, Japanese Patent Application Laid-Open No. 2-281915 describes polypropylene mixed with olefin rubber resins to improve elasticity. However, in this case, the compatibility between polypropylene and olefin rubber is poor, so that uniform mixing is difficult and mechanical strength is also low. Has its drawbacks.

The present invention is to solve the problems associated with the prior art as described above, by preparing a polypropylene-polybutene copolymer by a Ziegler-Natta mixed catalyst supported on a metallocene catalyst and magnesium chloride (MgCl ₂ ) An object of the present invention is to provide a polypropylene having improved stereoregularity and crystallinity and thus improved elasticity without a drop in physical properties such as mechanical strength.

That is, the present invention provides a metallocene catalyst, 0.1-50, which is a transition metal organic compound of group IVB of the periodic table per mole of Ziegler-Natta catalyst consisting of a transition metal of group IVB of the polymer periodic table and a halogen element in preparing a polypropylene elastomer by a polymerization reaction. A mixed catalyst composed of mol% is added, and the monomer constituting the polypropylene elastomer is characterized in that it is used in an amount of 0.5-50 mol% of 1-butene per mole of propylene and 1-buteneol propylene.

Hereinafter, the present invention will be described in detail.

In the present invention, the polypropylene elastomer refers to a block or an irregular copolymer of propylene and 1-butene, and the amount of 1-butene copolymerized with propylene may be used to improve the physical properties of the present invention without degrading other properties of polypropylene. 0.5-50 mol%, preferably 2-30 mol%, more preferably 5-10 mol% per mol of propylene.

If the amount of 1-butene is less than 0.5 mol% per mole of propylene, the mechanical strength is excellent but there is a problem of not improving the elasticity, and if it exceeds 50 mol%, there is a problem that the mechanical strength falls.

In addition, the polypropylene-polybutene copolymer of the present invention is polymerized using a metallocene catalyst and a Ziegler-Natta mixed catalyst, and the mixing ratio of the mixed catalyst is usually 0.1-50 mol of the metallocene catalyst content per mole of Ziegler-Natta catalyst. %, Preferably 1-10 mol%, more preferably 5-8 mol%.

If the metallocene catalyst content is less than 0.1 mol% per mole of Ziegler-Natta catalyst, there is a problem that the mechanical properties are lowered. If the metallocene catalyst content is more than 50 mol%, the mechanical properties are increased, but there is a problem of not having sufficient elasticity.

The Ziegler-Natta catalyst is a compound consisting of a transition metal of the Group IVB of the periodic table and a halogen element, and is supported by magnesium chloride (MgCl ₂ ). The transition metal of Group IVB of the periodic table is one selected from the group consisting of titanium, zirconium and hafnium, of which titanium and zirconium are preferred, and titanium is more preferably used.

Further, the metallocene catalyst may be a compound represented by the following formula (I), specifically as a transition metal organic compound having a group having a conjugated electron as a ligand.

Where A ₁ and A ₂ are each a hydrogen atom, a halogen atom, a hydrocarbon group of 5-10 carbon atoms, a halogenated hydrocarbon group of 5-10 carbon atoms, M is a transition metal of group IVB of the periodic table, and R ₁ is a carbon atom number A 6-12 alkyl group or aromatic group, R ₂ is a hydrogen atom, a halogen atom, a hydrocarbon group of 5-10 carbon atoms, a halogenated hydrocarbon group of 5-10 carbon atoms, B is a hydrocarbon group of 5-10 carbon atoms, It is a halogenated hydrocarbon group of 5-10 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group and butyl group, and examples of the aromatic group include cyclopentadiethyl group, indenyl group and fluoretyl group, and halogen atoms include fluorine and chlorine. have.

Meanwhile, in the present invention, in addition to the mixed catalyst of the Ziegler-Natta catalyst and the metallocene catalyst, an organoaluminum compound may be further used as a cocatalyst in an amount of 150-300 mg per 1 mg of the mixed catalyst, and used as a promoter as needed. As an organoaluminum compound, the aluminoxane compound represented by following formula (II) and (III) is mentioned.

In such aluminoxane, R is a hydrocarbon group such as methyl group, ethyl group, propyl group, butyl group, etc., R ₂ means that two R groups are connected to aluminum, and m is 2 or more, preferably 5-40 Is an integer.

On the other hand, in the present invention, the polymerization reaction used in the production of the polypropylene-polybutene copolymer is usually carried out in a gaseous phase or in a liquid phase, for example, in solution. When the polymerization reaction is carried out in the liquid phase, a hydrocarbon solvent may be used, and olefin itself may be used as a solvent. The hydrocarbons used as the solvent include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane and octadecane, cycloaliphatic compounds such as cyclopentane, methylcyclopentane, cyclohexane and cyclooctane. Aromatic hydrocarbons, such as hydrocarbon, benzene, toluene, and xylene, petroleum content, such as gasoline, kerosene, and diesel, etc. are mentioned.

Polymerization temperature is -50-200 degreeC normally, Preferably it is the range of 0-120 degreeC. The polymerization pressure is usually at normal pressure to 100 kg / cm 2, preferably at normal pressure to 50 kg / cm 2, and the polymerization reaction can be carried out by any of batch, semi-continuous and continuous methods, and the polymerization time is preferably about 1-3 hours.

In addition, if necessary, heat stabilizers, light stabilizers, flame retardants, carbon blacks, pigments, antioxidants, and the like, which are usually added to polypropylene, may be added.

On the other hand, the polypropylene elastomer produced by the method of the present invention can be mixed with low density polyethylene (LDPE), high density polyethylene (HDPE), polybutene, EP (ethylene / propylene) rubber and the like.

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

Example 1

The polymerization was carried out in a glass reactor with an external temperature controller, magnetic stirrer, monomer and nitrogen, and a valve. First, 200 ml of purified toluene and 250 mg of methylaluminoxane were charged into a sufficiently nitrogen-substituted reactor, and the mixture was sufficiently stirred at 30 ° C., and then saturated with monomer propylene / 1-butene (100 mol / 5 mol). Meanwhile, 5 ml of toluene, 50 mg of methylaluminoxane, 6.25 × 10 ^-6 moles of metallocene catalyst and 3.125 × 10 ^-5 moles of Ziegler-Natta catalyst mixture were prepared in advance, and the monomer was sufficiently saturated in the reactor, and then Catalyst was added. The polymerization was carried out continuously at a temperature of 50 ° C. and atmospheric pressure, and after 1 hour, a small amount of ethanol was added to the reactor to terminate the reaction. The mixture was poured into methanol added with hydrochloric acid, stirred for about 24 hours and washed again with water and methanol. The obtained polymer was dried in vacuo at 60 ° C. until a constant weight was measured, and the results are shown in Table 1 below.

Example 2

Except that the monomer ratio of propylene / 1-butene was 100 mol / 10 mol was carried out in the same manner as in Example 1, the physical properties were measured and the results are shown in Table 1 below.

Comparative Example 1

Except for using only propylene as a monomer was carried out in the same manner as in Example 1, the physical properties were measured and the results are shown in Table 1 below.

Comparative Example 2

Except not adding a mixed catalyst of Ziegler-Natta catalyst and metallocene catalyst was carried out in the same manner as in Example 1, the physical properties were measured and the results are shown in Table 1 below.

Comparative Example 3

Except for using 3.125 × 10 ^-5 mol of Ziegler-Natta catalyst and 5.25 × 10 ^-5 mol of metallocene catalyst, the same process as in Example 1 was carried out. Shown in

The flexural strength and the Izod impact strength were measured at room temperature by INSTRON after the injection specimen was prepared according to ASTM standard, and the stereoregularity was calculated by analyzing the pentad microstructure using a carbon 13-nuclear magnetic resonance spectrometer. , The crystallinity was calculated from the density of each sample using the density purchase tube.

As can be seen from Table 1, as the content of 1-butene increases in the polypropylene-polybutene copolymer, Izod impact strength is increased without improving physical properties such as stereoregularity, crystallinity, and flexural strength. Can be.

In addition, when the mixed catalyst of the Ziegler-Natta catalyst and the metallocene catalyst is not used, or the mixing ratio of the mixed catalyst is out of the range of the present invention, it has not been given sufficient elasticity.

Polypropylene elastomer produced by the method of the present invention is superior in the stereoregularity and crystals compared to the conventional polypropylene elastomer, the elasticity is improved in the state is not accompanied by a drop in physical properties such as mechanical strength.

Therefore, the polypropylene elastomer according to the method of the present invention may be molded into various products such as plates, films, containers, fibers, and the like.

Claims (3)

In the production of polypropylene elastomer by polymerization, 0.1-50 mol% of a metallocene catalyst, which is a transition metal organic compound of Group IVB of the Periodic Table per mole of Ziegler-Natta catalyst, consists of a transition metal of Group IVB of the Periodic Table and a halogen element during polymerization. A method for producing a polypropylene elastomer, comprising mixing a catalyst and using propylene and 1-butene as monomers constituting the polypropylene elastomer. The method of claim 1, wherein propylene and 1-butene are used in an amount of 0.5-50 mol% of 1-butene per mol of propylene. The method of claim 1, wherein the polypropylene elastomer is an irregular copolymer or a block copolymer.