JP6414032B2 - Propylene polymer production method - Google Patents

Description

  The present invention relates to a method for producing a propylene-based polymer. Specifically, in the polymerization of propylene using a polymerization reactor, by controlling the temperature in the reactor by specific heat removal, the formation of bulk polymer is sufficiently suppressed, and the propylene polymer is stably produced with high production efficiency. The present invention relates to a polymerization method that enables the production of

Propylene polymers are excellent in mechanical properties such as rigidity and heat resistance, have good moldability, can be manufactured at a relatively low cost, and are highly adaptable to environmental problems. Applied to usage.
For this reason, technical studies have been continued on the production process of polypropylene from the viewpoints of simplification of steps, reduction of production cost, improvement of productivity, and improvement of catalyst performance.

In the polypropylene production process, the performance of the catalyst was low at the time when polypropylene began to be produced industrially, and a step for removing catalyst residues and atactic polymer from the obtained polypropylene was necessary. A slurry using a solvent Mainly processes such as law.
Thereafter, as the catalyst performance has progressed significantly, the necessity of removing catalyst residues, atactic polymers and the like has been reduced, and the gas phase process has become mainstream at present.

  In the gas phase process, a highly activated type catalyst such as a supported catalyst is generally used in recent years. However, a highly activated catalyst or a metallocene catalyst developed by the recent progress in catalyst technology has been used. The adaptation of the new catalyst to the process, the suppression of the generation of the bulk polymer accompanying it, and the reduction of the amount of fine powder produced present problems as problems to be solved from the viewpoint of stable operation of the process.

In order to prevent the formation of massive amorphous polymer in gas phase polymerization, it is relatively difficult to remove the heat of polymerization in the catalyst supply section in the fluidized bed reactor. The temperature is likely to be unstable. For this purpose, the temperature and pressure in the reactor are determined by the liquid flow rate of the liquefied circulating gas that returns to the gas phase polymerization reactor, the exhaust gas flow rate outside the system, and the supply monomer gas flow rate using the heat of vaporization using a fluidized bed reactor. Has been proposed (see, for example, Patent Document 1), but there is room for improvement in terms of removal of polymerization heat in a fluidized bed reactor due to an increase in production volume or rapid grade change. It is inevitable that there is.
In addition, for the purpose of suppressing the formation of bulk polymer and maintaining the fluidized state, a gas phase polymerization method has been proposed in which the inner wall temperature of the reactor is cooled below the dew point of the flowing gas during polymerization in a fluidized bed reactor. However, the present inventors recognize that operation control is difficult due to local phase change.

  On the other hand, in the gas phase process, a horizontal polymerization reactor having a stirrer rotating around a horizontal axis was used as an olefin gas phase reactor of the type that removes the heat of polymerization using the heat of vaporization of liquefied propylene. A polymerization process (for example, see Patent Document 3) and a polymerization process (for example, Non-Patent Document 1) using a vertical polymerization reactor equipped with a stirrer that rotates around a vertical axis are known. The method of removing the heat of polymerization using the heat of vaporization of liquefied propylene is advantageous in that it can have a large heat removal capability even with a small facility.

When utilizing the heat of vaporization of liquefied propylene, it is a general method to extract gas from the reactor, liquefy it by cooling with a heat exchanger, and return it to the reactor again. The temperature at which the gas liquefies (dew point) depends on the pressure and the composition of the gas. Therefore, when a gas component having a low dew point such as hydrogen or ethylene is mixed with propylene alone, the amount of mixing increases. The dew point decreases. The cooling capacity of the heat exchanger is determined by the equipment. When the same equipment is used, the ability to liquefy gas decreases as the dew point of the gas component decreases, that is, the heat removal ability decreases.
Thus, in a production process in which a large amount of hydrogen or ethylene is present in the reactor, such as a propylene-based polymer having a high melt flow rate or a random polymer, due to a novel catalyst such as a highly activated catalyst or a metallocene catalyst, the catalytic activity becomes high. On the other hand, the generation of a bulk polymer due to a decrease in heat removal capability is inevitable.

  In order to cope with this problem, a method of suppressing polymer aggregates by changing the supply ports of the titanium-supported catalyst component and the promoter component in a horizontal polymerization reactor has been proposed (see, for example, Patent Document 4). . In addition, a method for suppressing a block-shaped amorphous polymer by pre-polymerization treatment with α-olefin and addition of a donor (see, for example, Patent Document 5) has also been proposed.

In addition, the applicant of the present invention applied to a reactor in a method for continuously producing a propylene-based polymer, particularly a low-crystalline propylene-based polymer, by a gas phase polymerization process in which the heat of reaction is mainly removed by the heat of vaporization of liquefied propylene. By limiting the temperature of the recycle gas of the propylene vapor to be supplied to a specific temperature, a method has been proposed in which the fluidity of the polymer is improved and the bulk polymer that inhibits stable operation is reduced (Patent Document 6). ).
Further, the applicant of the present invention is that at least the first polymerization step is carried out when continuously producing the propylene-based block copolymer in a two-stage process by the gas phase method in which the heat of reaction is mainly removed by the vaporization heat of the liquefied hydrocarbon. Proposed that a saturated hydrocarbon having 3 to 5 carbon atoms is added to a specific position in a range where the dew point of the reaction gas supplied into the reactor is 7 ° C. or more lower than the polymerization temperature. (Patent Document 7).
In addition, in the method for continuously producing a propylene-based polymer using a horizontal polymerization reactor, the applicant of the present invention relates to the temperature condition in the polymerization reactor and the temperature (Tx) of the section including the catalyst supply unit and the inside of the reactor. By setting the temperature difference ΔT1 (° C.) (= Tx−Tz) from the dew point (Tz) of the mixed gas to 0 to 5 ° C., the generation of bulk polymer is suppressed, the production efficiency is increased, and the transparency and A method for industrially and stably producing a propylene polymer excellent in low temperature heat sealability has been proposed (Patent Document 8).

Japanese Patent Laid-Open No. 11-209415 Japanese Patent No. 3,180,305 US Pat. No. 3,971,768 Japanese Patent Publication No. 7-94485 International Publication No. 00/42081 JP 2009-73890 A JP 2010-70584 A JP 2011-148980 A

J. et al. B. P. Soares, T .; F. L. McKenna, “Polyolefin Reaction Reaction”, Wiley-VCH Verlag GmbH & Co. KGaA (2012), Chapter 4, pp. 199 97-99

However, the method disclosed in Patent Document 4 does not sufficiently satisfy the suppression of aggregates and the production efficiency. Further, the method disclosed in Patent Document 5 has problems such as a decrease in catalyst performance due to donor addition.
In addition, the method disclosed in Patent Document 6 is a technique for improving the fluidity of the polymer and reducing the bulk polymer by increasing the temperature of the recycle gas within a specific temperature range before introducing the reactor. However, there is a further need for an improved technique for suppressing the generation of bulk polymer.
In Patent Document 7, when producing a high-flow polypropylene polymer, it is necessary to increase the hydrogen gas concentration, so the dew point of the recycled gas is lowered. However, a saturated hydrocarbon having 3 to 5 carbon atoms is added and recycled. By increasing the gas dew point, it is possible to suppress a decrease in the capacity of the condenser for recycling in the first polymerization step, and to produce a highly fluid polypropylene-based polymer. In this document, the partial pressure of propylene is reduced due to the presence of saturated hydrocarbon in the polymerization in the first polymerization step, and therefore, the catalyst is supplied to the second polymerization step while the activity of the catalyst in the first polymerization step is suppressed. Therefore, a sufficient activity inhibitor is supplied, and thereby a rapid reaction in the second polymerization step is suppressed, so that a high-flowing propylene-based block copolymer can be produced. Is described.
Patent Document 8 is a technique aiming to suppress the generation of bulk polymer and increase production efficiency by controlling the temperature of the catalyst supply section with respect to the dew point of the mixed gas in the reactor. The dew point of the mixed gas in the vessel is determined by the composition of the target polymer, and accordingly, the polymerization temperature is determined within a narrow range. According to Patent Document 8, the degree of freedom of production conditions is low, and there is a limit to increasing the reaction activity at the polymerization temperature. It was. Therefore, there is a further need for an improved technique that suppresses the generation of bulk polymer and increases production efficiency.

  As described above, in the prior art, in connection with the problem of heat removal from the polymerization reaction heat, the problem of suppressing the generation of a bulk polymer to increase production efficiency and stably producing a propylene polymer. A technology that sufficiently satisfies the above has not yet been realized, and further technical improvement is desired from this viewpoint.

  In view of the above situation, the problem in the present invention includes propylene or propylene and ethylene by a continuous polymerization method using a polymerization reactor that removes the heat of polymerization using the heat of vaporization of a liquefied monomer-containing liquid such as liquefied propylene. To provide a method for producing a propylene polymer stably while suppressing production of a bulk polymer in the production process of a propylene polymer obtained by polymerizing with other α-olefins to increase production efficiency. is there.

As described in Patent Document 8, the present inventors have described that a bulk polymer may be generated even if the difference between the dew point of the mixed gas in the reactor and the polymerization temperature of the catalyst supply unit is reduced. As estimated. That is, if the liquefied monomer-containing liquid used for heat removal immediately vaporizes around the catalyst supply section where the catalyst concentration is the highest and the initial polymerization heat is large, the heat removal efficiency of the liquefied monomer-containing liquid deteriorates or the catalyst Because there are few liquids in the surroundings and the reaction is slow, the ungrown catalyst is likely to adhere due to static electricity, heat is generated locally, the polymer is melted by heat, and a mass of hot melt is formed as a result. I guessed that.
On the other hand, the present inventors do not pay attention to the mixed gas in the reactor composed of the liquefied monomer-containing liquid and the raw material mixed gas including the recycle gas, but how long the liquefied monomer-containing liquid is around the catalyst. We focused on whether it can exist as a liquid. The inventors then set the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit. , Local heat generation is suppressed at the place where the catalyst concentration is the highest and the initial polymerization heat is large, the generation of bulk polymer can be suppressed, the production efficiency is improved and the propylene polymer is stably produced. As a result, the present invention has been found.

According to the first invention of the present invention, propylene or propylene and α-olefin excluding propylene are polymerized in the presence of a catalyst by a continuous polymerization method in which heat of reaction is removed by heat of vaporization of the liquefied monomer-containing liquid, A method for producing a propylene polymer, comprising:
Using a reactor that can set multiple zone sections with different temperatures in the longitudinal direction inside,
The propylene-based weight is characterized in that the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid is set to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit. A method for producing a coalescence is provided.

According to a second invention, in the first invention, the reaction heat is removed by the heat of vaporization of the liquefied monomer-containing liquid using a horizontal polymerization reactor equipped with a stirrer that rotates about a horizontal axis. A method for producing a propylene polymer by polymerizing propylene or an α-olefin excluding propylene in the presence of a catalyst by a continuous gas phase polymerization method,
The reactor is provided with a method for producing a propylene-based polymer, wherein a plurality of region sections having different temperatures in the horizontal axis direction can be set inside.

  According to a third invention, in the first or second invention, the temperature (Tx) of the region section including the catalyst supply unit is 50 ° C. or higher and 65 ° C. or lower. A method for producing a polymer is provided.

  According to a fourth invention, in any one of the first to third inventions, at least one selected from saturated hydrocarbons having 6 to 7 carbon atoms is a gas having a composition of the liquefied monomer-containing liquid. Provided is a method for producing a propylene-based polymer, characterized in that the dew point (Tq) is added in an amount sufficient to set the temperature (Tx) of the region section including the catalyst supply unit or higher. .

  According to the method for producing a propylene-based polymer of the present invention, heat of vaporization of a liquid containing a liquefied monomer such as liquefied propylene is used to remove the heat of polymerization, and propylene or other α-olefin containing propylene and ethylene by a continuous polymerization method. In the process for producing a propylene polymer obtained by polymerizing the above, the generation of bulk polymer can be suppressed to increase production efficiency, and the propylene polymer can be produced stably.

FIG. 1 is a schematic explanatory view showing an example of the arrangement of apparatuses used in the production method using the horizontal polymerization reactor of the present invention. FIG. 2 is a schematic explanatory view showing an example of the arrangement of apparatuses used in the production method using the horizontal polymerization reactor of the present invention.

The method for producing a propylene-based polymer of the present invention is obtained by polymerizing propylene or propylene and an α-olefin excluding propylene in the presence of a catalyst by a continuous polymerization method in which the heat of reaction is removed by the heat of vaporization of the liquefied monomer-containing liquid. , A method for producing a propylene polymer,
Using a reactor that can set multiple zone sections with different temperatures in the longitudinal direction inside,
The dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid is set to be equal to or higher than the temperature (Tx) of the polymer particles in the region including the catalyst supply unit.
Hereinafter, although the content is demonstrated in detail, it demonstrates in order of the monomer used for manufacture of the propylene-type polymer of this invention, a catalyst, a manufacturing process, polymerization conditions, and the propylene-type polymer manufactured by this invention.

I. Monomers used for production of propylene-based polymer of the present invention The “α-olefin” polymerized with propylene in the present invention is not particularly limited, but olefins having 2 to 12 carbon atoms, excluding propylene, particularly 2 to 2 carbon atoms. Twelve α-olefins are preferably used.
Specific examples of the α-olefin excluding propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene and 3-methyl-1- Among them, it is more preferable to use ethylene, 1-butene, 4-methyl-1-pentene, and these α-olefins can be used alone or in combination of two or more. . The α-olefin excluding propylene that is polymerized in the present invention is also referred to as “other α-olefin” in the present specification.

II. Catalyst The olefin polymerization catalyst used in the present invention includes (I) (1) a solid catalyst component containing titanium, magnesium, halogen and an electron donating compound as an internal donor as essential components, and (2) an organoaluminum compound. And, if necessary, (3) a polymerization catalyst composed of an electron donating compound as an external donor, that is, a Ziegler polymerization catalyst.
(II) (1) a metallocene complex composed of a transition metal compound, (2) a catalyst component containing a promoter for activating it as an essential component, and (3) an organoaluminum compound as required It is also possible to use a polymerization catalyst, that is, a metallocene polymerization catalyst. “Contained as an essential component” means that other elements may be included in addition to the components, that these elements may exist as arbitrary compounds, and these elements are bonded to each other. It may be present as a result.
The olefin polymerization catalyst that can be used in the present invention is preferably the aforementioned Ziegler polymerization catalyst or metallocene polymerization catalyst, but is not limited thereto.

(I) Ziegler-based polymerization catalyst (1) Titanium, magnesium, halogen and electron donating compound As the solid catalyst component itself containing titanium, magnesium and halogen, known ones can be used. For example, JP-A-53-45688, 54-3894, 54-31092, 54-39483, 54-94591, 54-118484, 54-131589, 55-75411 55-90510, 55-90511, 55-127405, 55-147507, 55-155003, 56-18609, 56-70005, 56-72001, 56-86905, 56-90807, 56-155206, 57-3803, 57-34103, 57-92007, 57-12003, 58-5309, 58 -5310, 58-5311, 58-8706, 58-27732, 58-32604, 58-326 No. 5, No. 58-67703, No. 58-117206, No. 58-127708, No. 58-183708, No. 58-183709, No. 63-108008, No. 63-264607, No. 63-264608 JP-A-1-79203, JP-A-1-98603, JP-A-7-258328, JP-A-8-269125, JP-A-11-21309, and the like are used.

Examples of the magnesium compound used as a magnesium source in the present invention include metal magnesium, magnesium dihalide, dialkoxymagnesium, alkoxymagnesium halide, magnesium oxyhalide, dialkylmagnesium, alkylmagnesium halide, magnesium oxide, magnesium hydroxide, and magnesium. Examples thereof include carboxylates. Among these, Mg (OR ¹ ) _2−m X _m such as magnesium dihalide and dialkoxymagnesium (where R ¹ is a hydrocarbon group, preferably about 1 to 10 carbon atoms, and X represents halogen. And m is 0 ≦ m ≦ 2).

As the titanium compound serving as a titanium source, the general formula _{^{Ti (OR 2) 4-n}} X n, where, ^{R 2} is a hydrocarbon group, preferably of 1 to 10 carbon atoms, X is a halogen Where n is 0 ≦ n ≦ 4. ). Specific examples include TiCl ₄ , TiBr ₄ , TiI ₄ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₃ Cl, Ti (O-i _{-C 3 H 7) Cl 3,} Ti (O-n-C 4 H 9) Cl 3, Ti (O-n-C 4 H 9) 2 Cl 2, Ti (OC 2 H 5) Br 3, Ti ( _{OC 2 H 5) (O-} n-C 4 H 9) 2 Cl, Ti (O-n-C 4 H 9) 3 Cl, Ti (OC 6 H 5) Cl 3, Ti (O-i-C 4 _{H 9) 2 Cl 2, Ti} (OC 5 H 11) Cl 3, Ti (OC 6 H 13) Cl 3, Ti (OC 2 H 5) 4, Ti (O-n-C 3 H 7) 4, Ti _{(O-n-C 4 H} 9) 4, Ti (O-i-C 4 H 9) 4, Ti (O-n-C 6 H 13) 4, _{Ti (O-n-C 8} H 17) 4, Ti (OCH 2 CH (C 2 H 5) C 4 H 9) 4 , and the like.

Further, a molecular compound obtained by reacting an electron donor described later with TiX ′ ₄ (where X ′ is a halogen) can also be used as a titanium source. Specific examples of such molecular compounds include TiCl ₄ · CH ₃ COC ₂ H ₅ , TiCl ₄ · CH ₃ CO ₂ C ₂ H ₅ , TiCl ₄ · C ₆ H ₅ NO ₂ , TiCl ₄ · CH ₃ COCl, TiCl ₄ · C ₆ H ₅ COCl, TiCl ₄ · C ₆ H ₅ CO ₂ C ₂ H ₅ , TiCl ₄ · ClCOC ₂ H ₅ , TiCl ₄ · C ₄ H ₄ O and the like can be mentioned.

In addition, TiCl ₃ (including TiCl ₄ reduced with hydrogen, aluminum metal reduced or organometallic compound reduced), TiBr ₃ , Ti (OC ₂ H ₅ ) Cl ₂ , TiCl ₂ , It is also possible to use titanium compounds such as dicyclopentadienyl titanium dichloride and cyclopentadienyl titanium trichloride. Among these titanium compounds, TiCl ₄ , Ti (OC ₄ H ₉ ) ₄ , Ti (OC ₂ H ₅ ) Cl _{3 and the} like are preferable.

The halogen is usually added from the aforementioned magnesium and / or titanium halogen compounds, but other halogen sources such as aluminum halides such as AlCl ₃ , AlBr ₃ , AlI ₃ , BCl ₃ , BBr ₃ , boron halides such as BI ₃ , silicon halides such as SiCl ₄ , phosphorus halides such as PCl ₃ and PCl ₅ , tungsten halides such as WCl ₆ , molybdenum halides such as MoCl _5, etc. It can also be added from a known halogenating agent. The halogen contained in the catalyst component may be fluorine, chlorine, bromine, iodine or a mixture thereof, and chlorine is particularly preferable.

Examples of electron donating compounds (internal donors) include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic or inorganic acids, ethers, acid amides, and acid anhydrides. Examples thereof include oxygen electron donors, nitrogen-containing electron donors such as ammonia, amines, nitriles, and isocyanates, sulfur-containing electron donors such as sulfonate esters, and the like.
Specific examples thereof include the compounds described in JP-A 2010-70584, paragraph 0037.

(2) Organoaluminum Compound As a specific example of the organoaluminum compound used in the present invention, R ¹ _3-s AlX _s or R ² _3-t Al (OR ³ ) _t (where R ¹ and R ² are the number of carbon atoms) 1 to 20 hydrocarbon groups or hydrogen atoms, R ³ is a hydrocarbon group, X is a halogen, and s and t are 0 ≦ s <3 and 0 <t <3, respectively. There is something to be done.
Specifically, (a) trialkylaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tri-n-decylaluminum, (b) diethylaluminum monochroma Aldehydes, alkylaluminum halides such as diisobutylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, (c) alkylaluminum hydrides such as diethylaluminum hydride, diisobutylaluminum hydride, (d) diethylaluminum ethoxide, diethylaluminum phenoxide, etc. Examples thereof include alkyl aluminum alkoxide.
As the organoaluminum compound, not only a single compound but also a plurality of compounds can be used in combination.

(3) Electron donating compound (external donor)
In addition to the above components as a catalyst component, an electron donating compound can also be used as an external donor if necessary.
Examples of such an electron donating compound include the compounds exemplified as the electron donating compound (internal donor) in (1). When such an electron donor compound as an external donor is used, it may be the same as or different from the electron donor compound as an internal donor.
Preferred electron donating compounds as external donors are ethers, inorganic acid esters, organic acid esters and organic acid halides, and organic silicon compounds, and particularly preferred are inorganic and organic silicate esters, phthalic acid esters, and acetic acid cellosolve esters. And phthalic acid halide.

Preferred silicate esters are those represented by the general formula R ¹ _v R ² _w Si (OR ³ ) _4-vw (wherein R ¹ is a branched aliphatic hydrocarbon having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms). A residue or a cyclic aliphatic hydrocarbon residue having 5 to 20 carbon atoms, preferably 6 to 10 carbon atoms, and R ² is a branched or straight chain aliphatic hydrocarbon having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms R ³ is an aliphatic hydrocarbon residue having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, v is 0 ≦ v ≦ 3, w is 0 ≦ w ≦ 3 and v + w ≦ 3, Respectively). R1 in the general formula is preferably branched from a carbon atom adjacent to the silicon atom.
Specifically, t-Bu (Me) Si (OMe) ₂ , t-Bu (Me) Si (OEt) ₂ , t-Bu (Et) Si (OMe) ₂ , t-Bu (n-Pr) Si. _{(OMe) 2, c-Hex} (Me) Si (OMe) 2, c-Hex (Et) Si (OMe) 2, c-Pen 2 Si (OMe) 2, i-Pr 2 Si (OMe) 2, i -Bu ₂ Si (OMe) ₂ , i-Pr (i-Bu) Si (OMe) ₂ , n-Pr (Me) Si (OMe) ₂ , t-BuSi (OEt) ₃ and others (Et ₂ N) _{2 Si (OMe) 2, Et} 2 N-Si (OEt) can be given ₃ or the like.

(II) Metallocene-based polymerization catalyst The metallocene-based polymerization catalyst is not particularly limited as long as it is a metallocene-based polymerization catalyst. Among them, the metallocene-based polymerization catalyst preferably used includes (1) a periodic table having a conjugated five-membered ring ligand. Examples include metallocene complexes composed of transition metal compounds such as Group 4; (2) co-catalysts for activating them; and (3) those composed of organoaluminum compounds used as necessary. .
Depending on the characteristics of the olefin polymerization process, when particle formation is essential, (4) a carrier can be added as a constituent element to the metallocene polymerization catalyst.

(1) Metallocene complex As a typical metallocene complex used in the present invention, a metallocene complex of a transition metal compound in Groups 4 to 6 of the periodic table having a conjugated five-membered ring ligand can be mentioned. Among these, what is represented by either the following general formula (1) or general formula (2) is preferable.

In said general formula, A and A 'are the cyclopentadienyl groups which may have a substituent. An example of this substituent is a hydrocarbon group having 1 to 30 carbon atoms (which may contain a hetero atom such as halogen, silicon, oxygen or sulfur). Even if this hydrocarbon group is bonded to the cyclopentadienyl group as a monovalent group, and when there are a plurality of these, two of them are bonded at the other end (ω-end) to form a cyclopenta A ring may be formed together with a part of dienyl. Examples of the ring include an indenyl group, a fluorenyl group, and an azulenyl group. These groups may further have a substituent on the side ring. Among these, an indenyl group or an azulenyl group is preferable.
Q represents a bonding group that bridges between two conjugated five-membered ring ligands at an arbitrary position, and specifically, is preferably an alkylene group, a silylene group, a silafluorene group, or a germylene group.
M is a metal atom of a transition metal selected from Groups 4 to 6 of the periodic table, preferably titanium, zirconium, hafnium or the like. In particular, zirconium and hafnium are preferable.
X and Y are auxiliary ligands that react with the cocatalyst to produce an active metallocene having olefin polymerization ability. Therefore, as long as this object is achieved, X and Y are not limited in the kind of ligand, and each may have a hydrogen atom, a halogen atom, a hydrocarbon group, or a hetero atom. Examples are groups. Among these, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom is preferable.

(2) Cocatalyst (activator component)
The cocatalyst is a component that activates the metallocene complex, and is a compound that can react with the auxiliary ligand of the metallocene complex to convert the complex into an active species having olefin polymerization ability. Specifically, (a ) An aluminum oxy compound, (b) an ionic compound or Lewis acid capable of reacting with the metallocene complex to convert the metallocene complex into a cation, (c) a solid acid, and (d) an ion-exchange layered silicate. .
These may be appropriately selected from known ones conventionally known as components for activating metallocene complexes.

(A) Aluminum Oxy Compound As the aluminum oxy compound, a known one that has been conventionally known as a component that activates a metallocene complex may be appropriately selected and used. Specific examples thereof include aluminoxanes and compounds that can be obtained by a reaction of 10: 1 to 1: 1 (molar ratio) between one type of trialkylaluminum or two or more types of trialkylaluminum and alkylboronic acid.
When aluminoxane is used, methylaluminoxane or methylisobutylaluminoxane is preferred. The above aluminoxanes can be used in combination within a group and between groups. And said aluminoxane can be prepared on well-known various conditions.

  Specific examples of (b) an ionic compound or Lewis acid capable of reacting with a metallocene complex to convert the metallocene complex into a cation, and (c) a solid acid include, for example, JP-A-2011-148980, paragraphs 0054 to And those described in 0058.

(D) Ion exchange layered silicate The ion exchange layered compound occupies most of the clay mineral, and is preferably an ion exchange layered silicate.
An ion-exchange layered silicate (hereinafter, sometimes simply referred to as “silicate”) has a crystal structure in which surfaces formed by ionic bonds and the like are stacked in parallel with each other and have a binding force. Refers to a silicate compound in which the ions to be exchanged are exchangeable. Most silicates are naturally produced mainly as a main component of clay minerals, and therefore often contain impurities (quartz, cristobalite, etc.) other than ion-exchanged layered silicates. You may go out.
Various known silicates can be used. Specific examples include the following layered silicates described in Haruo Shiramizu “Clay Mineralogy” Asakura Shoten (1995). 2: 1 type minerals such as montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite and other smectites; vermiculite and other vermiculites; Pyrophyllite-talc group such as pyrophyllite, talc, and chlorite group such as Mg chlorite. Examples of 2: 1 ribbon type minerals include sepiolite and palygorskite.

The silicate used as a raw material in the present invention may be a layered silicate in which the above mixed layer is formed. In the present invention, the main component silicate is preferably a silicate having a 2: 1 type structure, more preferably a smectite group, and particularly preferably montmorillonite. As the silicate used in the present invention, those obtained as natural products or industrial raw materials can be used as they are without any particular treatment, but chemical treatment is preferred. Specific examples include acid treatment, alkali treatment, salt treatment, organic matter treatment, and the like. These processes may be used in combination with each other. In the present invention, these treatment conditions are not particularly limited, and known conditions can be used.
In addition, since these ion-exchange layered silicates usually contain adsorbed water and interlayer water, it is preferable to use them after removing moisture by heat dehydration under an inert gas flow.
The ion-exchange layered silicate can be used in combination with a promoter and a carrier described later.

(3) Organoaluminum compound As the organoaluminum compound used as needed for the metallocene polymerization catalyst, the same compounds as shown in (I) the organoaluminum compound used in the Ziegler polymerization catalyst are used. The More preferred are triisobutylaluminum and trioctylaluminum. More preferred are triisobutylaluminum and tri-n-octylaluminum.

(4) Support When the present invention relates to a method for producing a propylene polymer using gas phase polymerization, it is preferable to use a supported catalyst using a support. Known carriers can be used, but preferred carriers include inorganic compound carriers such as silica, titania, alumina, silica-alumina, silica-magnesia, ion-exchange layered silicate, polypropylene powder, polyethylene powder and the like. There may be mentioned polymer carriers.
In order to adjust the shape of the propylene polymer particles and increase the particle diameter, it is preferable to use a carrier whose particle shape and particle diameter are controlled. The preferred particle size of the carrier is 1 to 200 μm, more preferably 10 to 150 μm.

As a method for producing the metallocene catalyst, a conventionally known method may be appropriately employed. As a method for granulating the inorganic compound carrier, specifically, for example, the method described in paragraphs 0043 to 0050 of JP2011-148980A can be employed.
In this manner, a supported catalyst having a maintained particle shape and particle size can be produced by supporting a metallocene complex on a granulated inorganic compound carrier.

3. Pre-polymerization treatment In the present invention, it is preferable to use a pre-polymerization treatment before use in the main polymerization, regardless of the use of any of the Ziegler polymerization catalyst and the metallocene polymerization catalyst. By using the prepolymerized catalyst, the generation of fine propylene polymer can be suppressed, and the powder characteristics of the propylene polymer can be improved.
The catalyst after pre-polymerization is covered with a polymer shell, but the average particle size (size including the polymer shell) of the catalyst used for the main polymerization is preferably 30 μm or more, more preferably 40 μm or more. Moreover, it is preferably 300 μm or less, more preferably 200 μm or less.

  The prepolymerization treatment of the polyolefin polymerization catalyst component can be carried out in the presence of the same organoaluminum compound as that described above. The temperature during the prepolymerization is 10 to 80 ° C. over 10 minutes to 48 hours, and 0.1 to 100 grams, preferably 0.5 to 50 grams of α-olefin per gram of the polyolefin polymerization catalyst component in an inert solvent. React.

  In the prepolymerization treatment, particularly in the Ziegler polymerization catalyst, the same electron donating compound as the above electron donating compound can be used. When the electron donating compound is an organosilicon compound, it may be used in an amount of 0.01 to 10 moles per mole of the organoaluminum compound.

  The α-olefin used for the prepolymerization treatment is ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene. 1-eicosene, 4-methyl-1-pentene, 3-methyl-1-pentene and the like, and these may be used alone or as a mixture of two or more with other α-olefins. Moreover, in order to adjust the molecular weight of the polymer produced during the polymerization, a molecular regulator such as hydrogen can be used in combination.

Inert solvents used in the prepolymerization process have a significant effect on the polymerization reaction, such as liquid saturated hydrocarbons such as hexane, heptane, octane, decane, dodecane, and liquid paraffin, and silicon oil with a dimethylpolysiloxane structure. There is no inert solvent. These inert solvents may be either one kind of single solvent or two or more kinds of mixed solvents.
When these inert solvents are used, it is preferable to use them after removing impurities such as moisture and sulfur compounds that adversely affect the polymerization.

  The prepolymerization treatment may be performed a plurality of times, and the monomers used at this time may be the same or different. Moreover, it can wash | clean with inert solvents, such as hexane and a heptane, after preliminary polymerization. After completion of the prepolymerization, the catalyst can be used as it is, depending on the usage form of the catalyst, but may be dried if necessary. Furthermore, a polymer such as polyethylene, polypropylene, or polystyrene, or an inorganic oxide solid such as silica or titania can be allowed to coexist during or after the contact of the above components.

III. Production process and polymerization conditions In the present invention, the production of a propylene polymer obtained by polymerizing propylene or propylene and another α-olefin is carried out by a continuous polymerization method in which the heat of reaction is removed by the heat of vaporization of the liquid containing the liquefied monomer. To do.
As the continuous polymerization method, any polymerization method that removes the heat of polymerization using the heat of vaporization of a liquefied monomer-containing liquid such as liquefied propylene can be used for a continuous gas phase polymerization method, a continuous solution polymerization method, and the like. The present invention is particularly preferably applied to a continuous gas phase polymerization method in which heat of reaction is removed by heat of vaporization of a liquefied monomer-containing liquid from the viewpoint that heat removal can be performed efficiently and economically.
In the present invention, the gas phase polymerization method does not mean that no liquid is present. The phase to be polymerized may be substantially a gas phase, and a liquid may exist within a range not departing from the gist of the present invention. Examples of this liquid include a liquefied monomer-containing liquid for heat removal, and an inert hydrocarbon such as hexane used as a solvent at the time of catalyst supply. The reaction in the liquid phase in which the catalyst diluted and supplied in the solvent reacts with the liquefied monomer dissolved in the solvent after the supply may be included in the gas phase polymerization of the present invention.

Moreover, arbitrary methods can be used as a method of removing heat using the heat of vaporization of the liquefied monomer-containing liquid.
In order to perform heat removal using the heat of vaporization of the liquefied monomer-containing liquid, a liquefied monomer-containing liquid that is in a liquid state, including liquefied monomer including liquefied propylene and other components, is supplied to the reactor. That's fine. Although fresh liquefied monomer can be fed to the reactor, it is generally desirable to use recycled monomer. A general procedure using recycled monomers is illustrated below.
Unreacted gas containing propylene is extracted from the reactor, the unreacted gas is cooled to liquefy at least a part, and at least a part of the liquefied components is supplied to the reactor. At this time, the component to be liquefied needs to contain propylene, but may contain a comonomer component typified by ethylene and an inert hydrocarbon component such as isobutane and hexane.

  In the present invention, removing the heat of reaction by the heat of vaporization of the liquefied monomer-containing liquid does not mean removing heat using only the heat of vaporization of the liquefied monomer-containing liquid. Other heat removal methods can be used in combination without departing from the gist of the present invention. Specifically, a method of removing heat using a jacket provided in the reactor, a method of extracting a part of the gas from the reactor, cooling it with a heat exchanger, and returning the gas to the reactor again, etc. Can do. However, in the present invention, it is necessary to mainly remove heat using the heat of vaporization of the liquefied monomer-containing liquid. Specifically, in at least one reactor, it is necessary to remove at least half of the heat removal amount using the heat of vaporization of the liquefied monomer-containing liquid.

In the present invention, the continuous polymerization method for removing the heat of reaction by the heat of vaporization of the liquefied monomer-containing liquid is performed using a reactor capable of setting a plurality of region sections having different temperatures in the longitudinal direction inside the reactor. . As such a reactor, for example, a horizontal polymerization reactor having a stirrer rotating around a horizontal axis, and a vertical polymerization reactor having a stirrer rotating around a vertical axis inside (for example, http http://www.cbi.com/images/uploads/audio/NOVOLEN_NEU_27.swf) and a polymerization reactor equipped with a circulation system for circulating the liquid phase part to the gas phase part (for example, JP-A-2011-2011). 236392) or the like can be used.
The longitudinal direction refers to the horizontal axis direction when the reactor is a horizontal polymerization reactor, and the vertical direction of the reactor when the reactor is a vertical polymerization reactor.

The reactor in the present invention is not limited to size, material, etc., as long as it is suitable for the reaction, depending on the raw materials used, reaction conditions, reaction form, products, etc. Is possible. The shape is preferably a horizontal polymerization reactor having a cylindrical portion. In order to perform heat removal using the heat of vaporization of the liquefied monomer-containing liquid, the reactor is extracted with a gas containing propylene from the reactor, and the gas is cooled to at least partially liquefy it, so that at least one of the liquefied components is obtained. It is preferable to include a recycle device for supplying a part to the reactor. The size of the reactor is arbitrary depending on each reaction form and the like. The volume is preferably 0.1 m ³ or more, and preferably 20 m ³ or more from the viewpoint of industrial productivity and economy. The length to diameter ratio is preferably 2.0 or more from the viewpoint of industrial productivity and economy.

In the present invention, in particular, a horizontal polymerization reactor equipped with a stirrer that rotates about a horizontal axis is used, and it can be applied to a continuous gas phase polymerization method in which the heat of reaction is removed by the heat of vaporization of a liquid containing a liquefied monomer. preferable.
The polymer particles polymerized in the horizontal polymerization reactor are formed in the stirring reactor, proceeding along the reactor while moving by stirring while proceeding with the polymerization, and are therefore a characteristic not found in other polymerization reactors. The plug flow type is a flow pattern in which several mixing tanks are arranged in series. Horizontal polymerization reactors are economically advantageous in that they can easily achieve a degree of solids mixing that is equivalent to two, three or more reactors in the ratio of length to diameter. Furthermore, since the polymerization reactor is a horizontal type, it is advantageous in that the heat of polymerization can be efficiently removed during heat removal as compared with the vertical type reactor. In such a horizontal polymerization reactor, the reaction heat is removed by the heat of vaporization of the liquid containing the liquefied monomer. In order to generate a large amount of vaporized gas, fine powder is entrained in the vaporized gas, and the gas exhaust pipe system pipe or filter In order to avoid adhering to or clogging these, it is desirable that the polymer particles have a particle shape as soon as possible upstream. On the other hand, since the reaction is promoted, a bulky amorphous polymer is likely to be generated due to local heat generation due to a rapid reaction. Therefore, the continuous gas phase polymerization method in which the reaction heat is removed by the vaporization heat of the liquefied monomer-containing liquid using a horizontal polymerization reactor is particularly effective in suppressing the generation of bulk polymer by using the process of the present invention. It is.
Hereinafter, the continuous gas phase polymerization method in which the heat of reaction is removed by the heat of vaporization of the liquefied monomer-containing liquid using a horizontal polymerization reactor which is a preferred embodiment of the present invention will be described in detail, but the technical idea of the present invention is: It is not limited to this.

FIG. 1 is a schematic explanatory view showing an example of the arrangement of apparatuses used in the production method using the horizontal polymerization reactor of the present invention. The horizontal polymerization reactor 10 is elongated and includes partition walls 10a and 10b, and is generally installed in a horizontal position as shown in FIG. The polymerization reaction is carried out in a space between the partition walls 10a and 10b in the horizontal polymerization reactor 10. In FIG. 1, the upstream partition 10 a is the reactor upstream end 12, and the downstream partition 10 b is the reactor downstream end 14. Although not shown, when the partition wall has a curved shape, the vertexes of each curved surface are the upstream end and the downstream end of the reactor.
The horizontal shaft 20 a of the stirrer 20 extends into the reactor downstream end 14 of the horizontal polymerization reactor 10, and a plurality of stirring blades 20 b for stirring are attached in the horizontal polymerization reactor 10. The stirring blade 20b mixes the polymer particles with other substances introduced into the horizontal polymerization reactor 10 therein.

The catalyst components introduced from the catalyst component supply pipes 1 and 2 of the horizontal polymerization reactor 10 start polymerization while being mixed with the polymer particles by the stirring blade 20b. As long as the catalyst component supply pipes 1 and 2 can measure the temperature of the region section including the catalyst supply unit in the positional relationship with the thermometer and the quench nozzle, the catalyst supplied to the polymerization reactor and the liquefied monomer-containing liquid can be mixed. , Can be installed at any position. The catalyst can be supplied from any position, but is preferably supplied from the upper part of the upstream portion of the reactor. This is because when the catalyst component is added to the upstream portion of the reactor, it can move to the downstream side of the reactor while growing as polymer particles by polymerization. In addition, since the liquefied monomer-containing liquid used for heat removal in the horizontal polymerization reactor is usually supplied from the upper part of the reactor, the catalyst supply section and the liquefied monomer supply pipe exist close to each other, and the operation described below of the present invention is more effective. It is because it becomes easy to obtain.
The polymerization catalyst of the present invention and other optional components can be supplied to the reactor using a known method. The polymerization catalyst may be supplied to the reactor as it is in the form of powder, but may be supplied after being diluted with an inert solvent such as liquid saturated hydrocarbon or mineral oil.
In addition, other components constituting the polymerization catalyst such as an organoaluminum compound may be supplied as a component in the catalyst after being contacted with the Ziegler solid catalyst component or the metallocene complex component, or supplied separately from these components. Also good.

The catalyst component supply pipe 1 is a pipe for supplying a main component of the catalyst, for example, a solid catalyst component containing a solid catalyst component or a metallocene complex, and other polymerization catalyst components. In the catalyst component supply pipe 1, the position of the partition wall 10a is expressed as 0 (L) and the position of the partition wall 10b is expressed as 1L in the direction from the partition wall 10a to the partition wall 10b with respect to the distance L between the partition wall 10a and the partition wall 10b. It is desirable to install between 1 / 9L and 2 / 9L or less from the partition wall 10a. When it is at a position of 1/9 L or more from the partition wall 10a, it is difficult for the catalyst to adhere to the inner wall of the reactor, the generation of aggregates and bulk polymer can be suppressed, and the operation stability can be improved. When it is at a position of 2/9 L or less from the partition wall 10a, the residence time of the catalyst in the reactor is not too short, and a decrease in activity can be suppressed, which is economically advantageous.
The catalyst component supply pipe 2 is a pipe for supplying a cocatalyst, an organoaluminum compound, and other polymerization catalyst components, and preferably, the partition walls 10a to 0 (L) with respect to the distance L between the partition walls 10a and 10b. It is good to install between 2 / 9L or less. The catalyst component supply pipe 1 and the partition wall 10a are preferably located at the same distance or upstream.
Further, the catalyst component supply pipes 1 and 2 may be used as required, and a plurality of catalyst component supply pipes 1 and 2 may be used within the above ranges. The catalyst component supply pipe 1 may also serve as the catalyst component supply pipe 2.

The polymerization heat generated during the polymerization is removed by the heat of vaporization of the liquefied monomer-containing liquid containing the raw material liquefied propylene supplied from the liquefied monomer-containing liquid supply pipe 19.
The liquefied monomer-containing liquid introduced into the horizontal polymerization reactor 10 from the liquefied monomer-containing liquid supply pipe 19 is polymerized while being mixed with the polymer particles by the catalyst component and the stirring blade 20b.

  As a method for supplying the liquefied monomer-containing liquid used for heat removal, any method can be used as long as the liquefied monomer-containing liquid in a substantially liquid state is supplied to the reactor. When present in the upper part of the reactor, the liquefied monomer-containing liquid is preferably supplied from the upper part of the reactor to the gas phase part inside the reactor. This is because when both the catalyst supply unit and the liquefied monomer supply pipe are present in the upper part of the reactor, the action described below of the present invention is more easily obtained.

In particular, in the region section including the catalyst supply unit, it is necessary to supply the liquefied monomer-containing liquid at at least one place, and the position is from the partition wall 10a to the distance L between the partition wall 10a and the partition wall 10b. It is good to install between 0 (L) and 2 / 9L or less.
Further, in the area section including the catalyst supply unit, it is particularly preferable to install the catalyst component supply pipe 1 at the same distance or upstream from the partition wall 10a.
Moreover, in the area | region division in which a catalyst supply part is included, you may supply a liquefied monomer containing liquid in several places.

Unreacted gas is discharged out of the reaction system through an unreacted gas extraction pipe 13, part of which is condensed by a condenser 15, and separated into a liquid phase and a gas phase by a recycle drum 11. The liquid phase part is reintroduced into the liquefied monomer-containing liquid supply pipe 19 for removing the polymerization heat. The gas phase part is mixed with hydrogen, α-olefin or the like for molecular weight adjustment from the pipe 4, pressurized by the compressor 16, and via the raw material mixed gas supply pipe 18 installed at the bottom of the horizontal polymerization reactor 10. Resupplied.
At this time, the flow rate of the liquefied monomer-containing liquid from the liquefied monomer-containing liquid supply pipes 19-1, 19-2, 19-3, 19-4, 19-5 arranged at a specific interval at the top, and The flow rate of the mixed gas whose temperature is controlled from the raw material mixed gas supply pipes 18-1, 18-2, 18-3, 18-4, and 18-5 arranged at a specific interval below can be individually controlled. . Each flow rate is controlled by an operation valve installed in each of the liquefied monomer-containing liquid supply pipe and the raw material mixed gas supply pipe.
The polymer particles move from the upstream portion to the downstream portion in the polymerization tank while being mixed with the reaction, and are discharged out of the reaction system through the polymer extraction pipe 21. The discharged powder is separated into gases by the gas recovery unit 22, and the polymer particles are recovered by the powder recovery unit 23.

  In the horizontal polymerization reactor of the present invention, it is possible to set a plurality of zone sections having different temperatures in the horizontal axis direction, and the zone zone including the catalyst supply unit is defined in the horizontal axis direction inside the reactor. When a plurality of area sections with different temperatures are set, the area section including the catalyst component supply pipe among the plurality of area sections. When there are a plurality of catalyst component supply pipes, the main component of the catalyst is The catalyst component supply piping to be supplied, that is, a region section including the catalyst component supply piping 1 as shown in FIG. The polymerization temperature of each region segment is measured by measuring the temperature of the polymer particles being stirred by the stirrer with a thermometer installed in the reactor of each region segment, that is, the temperature of the polymer particles in each region segment. Say. The temperature of the polymer particles being stirred by the stirrer rotating around the horizontal axis is considered to indicate an average value in the region section around the horizontal axis.

  In the present invention, not focusing on the dew point of the mixed gas in the reactor as in the past, but focusing on how long the liquefied monomer-containing liquid used for heat removal can exist as a liquid around the catalyst. . In the present invention, the liquefied monomer-containing liquid used for heat removal is not the boiling point of the liquefied monomer-containing liquid that begins to become a gas, but the temperature at which all of the liquefied monomer-containing liquid cannot be liquid, that is, the liquefied monomer-containing liquid is The dew point (Tq) at the polymerization pressure of the mixed gas of the composition of the liquefied monomer-containing liquid was defined as an index of the temperature at which the gasification is complete under the polymerization pressure. The dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid is set to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit, that is, the polymerization temperature of the catalyst supply unit. As a result, the time during which the liquefied monomer-containing liquid exists as a liquid at a place where the concentration of the catalyst is the highest and the initial polymerization heat is large immediately after the catalyst supply and before the dispersion becomes long. As a result, the heat removal efficiency of the liquid containing the liquefied monomer increases, and at the same time, the catalyst grows into polymer particles that weaken the electrostatic force due to the reaction with the liquid, thereby preventing electrostatic adhesion of the catalyst, resulting in locally high heat generation. It is presumed that the generation of bulk polymer can be suppressed, the production efficiency can be increased, and the propylene polymer can be stably produced. According to this invention by such an effect | action, there exists an especially remarkable effect that a block polymer does not generate | occur | produce even if it operates for a long term compared with a prior art.

Further, as described above, Patent Document 8 is a technique for controlling the temperature of the catalyst supply unit so as not to be too high with respect to the dew point of the mixed gas in the reactor. Is determined by the composition of the target polymer, and accordingly, the polymerization temperature is determined within a narrow range. Therefore, according to the technique of Patent Document 8, the degree of freedom of production conditions is low, and there is a limit in increasing the reaction activity at the polymerization temperature.
On the other hand, in the present invention, attention is paid to the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid used for heat removal. As described above, the liquefied monomer-containing liquid used for heat removal is discharged out of the reactor through the unreacted gas extraction pipe, partially condensed by the condenser, and converted into the liquid phase and gas phase by the recycle drum 11. It is a liquid phase part of the separated components, and may contain hydrogen, nitrogen, an inert solvent used for the catalyst slurry, etc. in addition to the liquefied monomer. A high-boiling substance can be intentionally added to the liquefied monomer-containing liquid used for heat removal until it is introduced into the reactor through the liquefied monomer-containing liquid supply pipe 19. Therefore, the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid can be controlled by adjusting the operating conditions of the recycle drum or introducing a high boiling point substance. The polymerization temperature can be freely set even in a range not satisfying the above condition. Therefore, in the case of producing a polymer having the same composition, it is possible to polymerize at a higher polymerization temperature than when the technique of Patent Document 8 is used, while suppressing the generation of a bulk polymer, increasing production efficiency, and stable. Thus, a propylene-based polymer can be produced.

In addition, the dew point (Tq) in the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid can be calculated as follows.
First, the composition of the liquefied monomer-containing liquid is measured using gas chromatography. For example, liquefied propylene a mol%, liquefied ethylene b mol%, liquefied hydrogen c mol%, liquefied n-hexane d mol%, liquefied propane e mol%, liquefied nitrogen f mol% and each mol% can be measured. In this case, unavoidable impurities are ignored and a + b + c + d + e + f = 100.
On the other hand, the polymerization pressure (P) in the reactor is measured using a pressure gauge.
Mixed gas having the composition of the liquefied monomer-containing liquid, that is, propylene gas a mol%, ethylene gas b mol%, hydrogen gas c mol%, n-hexane gas d mol%, propane gas e mol%, nitrogen gas f mol% The dew point (Tq) at the polymerization pressure (P) of the mixed gas containing, using an algorithm such as Microsoft Excel (registered trademark) Solver (registered trademark) as shown in (i) to (iv) below To obtain the convergence value.
(I) The saturated vapor pressure (Pi) of each component i at the temperature (T) is determined using the following Antoine equation and various necessary constants.
Antoine formula:
log (P [mmHg]) = AB / (T [° C.] + C)
Here, P is the vapor pressure, T is the temperature, A, B, and C are constants depending on the substance, vapor pressure, and temperature units, and are called Antoine constants. Various constants necessary for the calculation can be used with reference to Chemical Handbook, Basic Edition, Rev. 5 II-117-135 (Maruzen Co., Ltd.).
(Ii) Subsequently, the saturated vapor pressure (Pq) of the entire liquefied monomer-containing liquid is determined from Raoul's law and equation.
(Iii) T when Pq is equal to the polymerization pressure P is determined as a convergence value using an algorithm such as Microsoft Excel (registered trademark) Solver (registered trademark).
(Iv) The convergence value of T is the dew point (Tq).

In particular, in the present invention, in order to set the dew point (Tq) at the polymerization pressure of the mixed gas of the composition of the liquefied monomer-containing liquid to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit, It is preferable that the liquefied monomer-containing liquid contains an inert high-boiling substance that has a high boiling point and does not react with a monomer such as propylene. When such an inert high-boiling substance is added, the temperature (Tx) of the polymer particles in the region section including the catalyst supply part, that is, the polymerization temperature can be increased, thereby improving the production efficiency. It becomes possible to do.
As the inert high-boiling substance, saturated hydrocarbons are preferably used, and saturated hydrocarbons having 4 to 8 carbon atoms are preferably used. If the carbon number is smaller, the dew point in the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid needs to be increased so that the partial pressure of the saturated hydrocarbon becomes too high. There is a risk that the partial pressure cannot be increased and the catalyst efficiency cannot be increased. On the other hand, if the carbon number is larger, it becomes difficult to control the dew point. Further, when it remains in the product polymer, it cannot be completely removed even after a drying process, and there is a risk of odor problems. Therefore, among them, at least one selected from saturated hydrocarbons having 6 to 7 carbon atoms represents the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid, and the polymer particles in the region section including the catalyst supply unit It is preferable to be included in order to set the temperature (Tx) or higher.

  Examples of saturated hydrocarbons having 6 to 7 carbon atoms include n-hexane, 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane, 2,2-dimethylbutane, cyclohexane, n-heptane, and 2-methylhexane. , 3-methylhexane, 2,4-dimethylpentane, 2,3-dimethylpentane, 2,2-dimethylpentane, 3,3-dimethylpentane, 3-ethylpentane, 2,2,3-trimethylbutane, cycloheptane Etc. Especially, at least 1 sort (s) of n-hexane and n-heptane is used suitably from the point which is easy to acquire industrially.

  The inert high-boiling substance is added in an amount sufficient to set the dew point (Tq) of the gas of the composition of the liquefied monomer-containing liquid to be equal to or higher than the temperature (Tx) of the region section including the catalyst supply unit. Just do it. In the composition of the liquefied monomer-containing liquid, the content of the inert high-boiling substance, particularly the saturated hydrocarbon having 4 to 8 carbon atoms, is 1 mmol or more and 50 mmol or less with respect to 1 mol of liquefied propylene. More preferably, it is 4 mmol or more and 30 mmol or less. If the content of the inert high-boiling substance is too small with respect to liquefied propylene, it is not effective in increasing the dew point. On the other hand, if the content of liquefied propylene is too large, the partial pressure of the saturated hydrocarbon is reduced. As a result, the propylene partial pressure may not be increased and the catalyst efficiency may not be increased.

  Further, the content (mol%) of the saturated hydrocarbon having 4 to 8 carbon atoms in the liquefied monomer-containing liquid is the content of the saturated hydrocarbon having 4 to 8 carbon atoms contained in the mixed gas in the reactor. It is preferably 1.5 or more and 5.0 or less with respect to 1 mol% of the amount, and further 1.8 or more and 4.0 or less can reduce the residual amount of high boiling point compounds in the product polymer. It is preferable from the point which can be performed.

In the present invention, in order to adjust the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid, as illustrated in FIG. 1, the raw material monomer supply pipe 3 introduced into the recycle drum 11 and the pipe 5 and the inert high-boiling substance can be introduced from at least one of the pipes 6 directly introduced into the liquefied monomer-containing liquid supply pipe.
When introducing from the raw material monomer supply pipe 3 to be introduced into the recycle drum 11, the inert high-boiling substance can be introduced directly into the liquid phase portion of the recycle drum, so that the liquefied monomer is introduced rather than being introduced into the gas elsewhere. Reflection time to the composition (dew point) of the contained liquid can be shortened and control is easy. As a result, it is preferable because production efficiency can be increased.

  The dew point (Tq) of the gas having the composition of the liquefied monomer-containing liquid can be set as follows so as to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit. First, the raw material gas composition is determined according to the composition of the target polymer, while the desired polymerization temperature, that is, the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit, and the polymerization pressure. To decide. Next, the operating conditions of the recycling drum, such as temperature and pressure, are adjusted from the raw material gas composition and, optionally, the mixed gas composition in the reactor including the inert solvent of the catalyst, so that the liquid phase and gas in the recycling drum are adjusted. The composition of the liquid phase portion separated into phases is measured using gas chromatography. From these conditions, the dew point (Tq) of the gas of the composition of the liquefied monomer-containing liquid is calculated as described above. Adjusting the operating conditions of the recycle drum, such as temperature, pressure, and / or the like so that the dew point (Tq) is equal to or higher than the temperature (Tx) of the polymer particles in the region section including the desired catalyst supply section The composition is adjusted by introducing a high boiling point substance into the liquefied monomer-containing liquid.

  The dew point (Tq) of the gas of the composition of the liquefied monomer-containing liquid may be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply part. That is, in the present invention, The temperature difference ΔT (° C.) (= Tq−Tx) between the dew point (Tq) of the composition gas and the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit may be 0 ° C. or more. Among them, the ΔT is more preferably 2 ° C. or higher, and further preferably 3 ° C. or higher. More preferably, it is 18 degrees C or less, More preferably, it is 15 degrees C or less. When the temperature difference ΔT is within this range, the liquid monomer-containing liquid is more stable and has a higher probability of being present as a liquid around the catalyst, and the bulk polymer due to melting of the polymer produced by local heat generation due to insufficient heat removal. It is because it can prevent becoming easy to generate | occur | produce. On the other hand, if the temperature difference ΔT is too large, the time during which the liquefied monomer exists in the liquid becomes too long, so that the liquid cross-linking force increases, so-called stickiness increases, and the stirring efficiency may be deteriorated.

Next, a method for measuring the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit in the horizontal polymerization reactor will be described in detail with reference to FIG. As shown in FIG. 2, the temperature (Tx) of the polymer particles in the region section (Z1) including the catalyst supply unit is thermometers 34-1 and 34- installed in the region section (Z1) including the catalyst supply unit. 2 is detected. The thermometers 34-1 and 34-2 installed in the zone section (Z1) including the catalyst supply unit can measure the temperature of the polymer particles in the vicinity of the catalyst component supply pipe 31 to which the main component of the catalyst is supplied. What is necessary is just to install suitably in the catalyst component supply piping 31 vicinity. Among them, the intersection of the catalyst component supply pipe 31 between the perpendicular and the horizontal axis 35 to the horizontal axis 35 and x _0, the intersection of the perpendicular and the horizontal axis 35 from the thermometer 341 to the horizontal axis 35 and x _1, the intersection of the perpendicular and the horizontal axis 35 to the horizontal axis 35 and x ₂ from the thermometer 34-2, the distance between the downstream side of the partition wall 33 from the upstream side of the partition wall 32 when is L, the intersection x ₀ and the intersection x ₁ each intersection _{x 0} and the distance of the intersection point _{x 2} is preferably in the range of 0 to 1/9 L, it is even more preferably in the range of 0 to 1 / 12L, a range of 0 to 1 / 15L It is still more preferable that If the thermometer is set within the above range, the polymerized temperature of the catalyst supply unit is faithfully expressed by the stirred polymer. Therefore, the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit is set. There may be one thermometer for measurement. At least one thermometer installed in the area section including the catalyst supply unit is installed on each of the upstream side and the downstream side of the catalyst component supply pipe 31 like the thermometers 34-1 and 34-2 in FIG. It is preferred that If the temperatures of the thermometers 34-1 and 34-2 installed on the upstream side and the downstream side of the catalyst component supply pipe 31 are the same, at least the region section sandwiched between 34-1 and 34-2 is the catalyst supply unit. The temperature of the thermometers 34-1 and 34-2 indicates the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit.
Further, when two or more thermometers are used as the thermometers for measuring the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit, at least one of the thermometers 34-1 is a distance from the partition wall 32 to the partition wall 33. Is set between L (0) and x _{0 in} the direction from the partition wall 32 toward the partition wall 33, where the position of the partition wall 32 is expressed as 0 (L) and the position of the partition wall 33 is expressed as 1 L on the horizontal axis 35. it is preferable to be, and is more preferably installed between 1/9 L position x _0. Further, at least one thermometer 34-2 it is preferred to set between the position of 1 / 3L from the position of x _0, can be installed from the position of x ₀ between the position of 2/9 L More preferred.
If the thermometers 34-1 and 34-2 are installed within the above range, the polymerization temperature of the catalyst supply unit is more faithfully expressed by the stirred polymer.
In addition, when the temperature in the reactor is constant without setting a plurality of region sections having different temperatures in the horizontal axis direction inside the reactor, the thermometers 34-1 and 34-2 are installed at any location. May be.

In the steady operation state, the entire horizontal polymerization reactor forms a polymer bed, and the polymerization reaction is performed in all regions.
Polymerization conditions such as pressure, residence time, and temperature can be arbitrarily set without departing from the gist of the present invention.
Specifically, the polymerization pressure is preferably 1200 kPa or more, more preferably 1400 kPa or more, particularly preferably 1600 kPa or more, preferably 4200 kPa or less, more preferably 3500 kPa or less, particularly preferably 3000 kPa or less. In general, in the horizontal polymerization reactor, the gas phase is circulated, so that the polymerization pressure in the same reactor is kept constant. It is also possible to physically divide by the weir shape installed in the reactor.

The residence time can be arbitrarily adjusted according to the configuration of the reactor and the intended polymer. Generally, it is set within a range of 30 minutes to 5 hours.
The polymerization temperature is preferably 0 ° C. or higher, more preferably 30 ° C. or higher, particularly preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 90 ° C. or lower, particularly preferably 80 ° C. or lower.
In the present invention, the temperature (Tx) of the region section including the catalyst supply unit is particularly selected from the viewpoint of suppressing the generation of the bulk polymer and increasing the production efficiency and stably producing the propylene polymer. It is preferably set to be 50 ° C. or higher and 65 ° C. or lower, and more preferably 55 ° C. or higher and 65 ° C. or lower.

  In the horizontal polymerization reactor used in the present invention, it is possible to set a plurality of zone sections having different temperatures in the horizontal axis direction. In the present invention, the area section does not indicate a physical area section using a weir but a temperature control execution area section.

Here, an example of temperature control in the horizontal polymerization reactor will be described in detail with reference to FIG. The horizontal polymerization reactor 30 is an example in which partition walls 32 and 33 are provided, and the region is divided into i sections Z1. The upstream partition 32 is the reactor upstream end, and the downstream partition 33 is the reactor downstream end. In FIG. 2, the section Z1 is a region section including the upstream end, and the section Zi is a region section including the downstream end. In FIG. 2, the catalyst component is supplied from the catalyst component supply pipe 31 of the reactor, and the region section including the catalyst supply unit is the section Z1. In FIG. 2, the stirrer is omitted.
The reaction heat generated during the polymerization is removed by the heat of vaporization of the liquefied monomer-containing liquid supplied from the liquefied monomer-containing liquid supply pipe. The polymerization temperature in each region section is detected by thermometers 34-1, 34-2, 34-3, 34-4, ... 34-i, etc. installed in each region section.
In the present invention, the polymerization temperature in the reactor can be controlled individually at different temperatures by the reactor temperature Ti of the plurality of zone sections (Zi) by a thermometer installed in the reactor.
The polymerization temperature in each zone is the flow rate of the liquefied monomer-containing liquid from the liquefied monomer-containing liquid supply pipe arranged at a specific interval at the upper part, and the raw material mixed gas supply pipe arranged at a specific position at the lower part Can be controlled individually by a combination of temperature-controlled mixed gas flow rates.

  In general, the same reaction conditions are used in a single polymerization reactor, but in the present invention, when the reactor is divided into i (i is an arbitrary integer of 2 or more) region sections from upstream to downstream, The n-th region segment (n) from the upstream end to the downstream end of the horizontal polymerization reactor according to the invention (n is an integer of 1 to (i-1)) and the downstream downstream region segment (n + 1) By setting each reaction temperature Tn and Tn + 1 so that Tn ≦ Tn + 1, it is possible to control the polymerization temperature according to the polymerization characteristics of the catalyst, and to suppress bulk polymer due to poor heat removal due to local heat generation, etc. It is preferable from the point of being effective.

  In this case, the thermometer to be installed is arbitrary depending on the reactor volume, reaction form, etc., but it is preferable to control at least the upstream, middle and downstream portions in the reactor (equivalent to i = 3). When the distance from the partition wall 32 to the partition wall 33 is L, the position of the partition wall 32 is expressed as 0 (L) and the position of the partition wall 33 is expressed as 1 L on the horizontal axis 35 in the direction from the partition wall 32 to the partition wall 33. It is preferable to install three or more thermometers at least one at a position between 1 / 3L, 1 / 3L to 2 / 3L, and 2 / 3L to 3 / 3L. That is, the number i of area sections is preferably 3 or more.

In the present invention, the temperature difference ΔT1 (° C.) (= Tω−Tα) between the temperature (Tα) of the region section including the upstream end of the reactor and the temperature (Tω) of the region section including the downstream end is 0. It is preferable that it is 1 degreeC or more and 20 degrees C or less from the point which obtains the effect of the productivity improvement accompanying the temperature rise in a reactor downstream part. If ΔT1 exceeds 20 ° C., the temperature change in the single reactor becomes large, which may cause a change in the composition of the polymer.
In the present invention, the temperature (Tα) of the region section including the upstream end of the reactor and the temperature (Tω) of the region section including the downstream end are respectively the temperature of the most upstream region section and the most downstream of the reactor. And the temperature of the polymer particles in each region.
Each thermometer is preferably installed at a position having a distance of 1/9 L to 2/9 L from the upstream end of each region section of the horizontal axis 35.

In the present invention, the temperature difference ΔT2 (° C.) (= Tx−Tz) between the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit and the dew point (Tz) of the mixed gas in the reactor is It is preferable that it is -3 degreeC or more and 20 degrees C or less.
ΔT2 is more preferably 0 ° C. or higher, and further preferably 1.5 ° C. or higher, regarding the lower limit. The upper limit is more preferably 18 ° C. or lower, and further preferably 15 ° C. or lower. If the temperature difference ΔT2 is less than this lower limit value, the polymerization temperature and the dew point of the mixed gas in the reactor will be too close, and the polymerization gas may condense in the reactor and the target reaction pressure may not be maintained. . Further, if the temperature difference ΔT2 exceeds the upper limit, the heat removal is increased by sensible heat after the liquefied monomer-containing liquid is vaporized, and the amount of heat removed per unit volume of the liquefied monomer-containing unit is increased. There is a risk that a bulk polymer may be generated due to melting of the produced polymer due to local heat generation due to insufficient heat removal. In particular, if the temperature difference ΔT2 exceeds the upper limit by making the polymerization temperature too high, in addition to the above reasons, the powder morphology is deteriorated due to a rapid reaction, and pulverization due to stirring and fluidization of the gas tends to occur. In particular, the amount of entrainment may be increased due to an increase in generation of fine powder due to powder pulverization during stirring.
In addition, the dew point (Tz) of the mixed gas in the reactor can be calculated by the same method as when the dew point (Tq) of the liquefied monomer-containing liquid is obtained using the gas chromatographic analysis value of the mixed gas. .

In addition, the entrainment amount in the present invention refers to the production amount of the propylene polymer, passes through an unreacted gas extraction pipe installed on an upper tank wall or the like (or may be a side portion or a bottom portion) of the reactor, together with the gas. It means the amount of particles carried out of the reactor. As a specific method for measuring the amount of entrainment, the amount [g / kg] of fine powder removed by a fine particle removing facility such as a cyclone or bag filter installed in front of the condenser is weighed and divided by the production amount. A method can be illustrated.
When producing a propylene-based polymer, the amount of entrainment is preferably 0.10 g / kg or less.
If this value is high, there is a possibility that the load or adhesion to the gas discharge pipe system will increase due to the increase in entrainment, or that the gas condensing capacity will decrease due to the flow of fine powder into the condenser.

When polymerization is carried out in a horizontal polymerization reactor, propylene polymer particles grow gradually along the axial direction of the reactor by the two forces of propylene polymer formation and mechanical stirring by the polymerization reaction. As it progresses, the flow pattern becomes a plug flow type. Therefore, the propylene-based polymer can receive different temperature histories from the catalyst supply port to the powder discharge port in the same reactor.
By adopting the method according to the present invention, regardless of the Ziegler catalyst or the metallocene catalyst, suppression of disordered polymerization reaction due to local heat generation in the catalyst supply section, particularly rapid random copolymerization of propylene with ethylene or α-olefin, This is an effective means for suppressing the formation of a bulk polymer that occurs because a high polymerization rate is likely to occur.
By suppressing the bulk polymer in the reactor, it becomes possible to further improve the continuity of production and the stability of operation. Further, the catalyst activity is kept high, and the manufacturing cost can be suppressed, which is economical.

IV. Propylene polymer produced in the present invention The propylene polymer produced in the present invention includes: [i] a propylene homopolymer, [ii] a random copolymer containing propylene and one or more α-olefins, and [ iii) a block copolymer, and [iv] an olefin polymer component supported in a prepolymerization catalyst obtained through a prepolymerization step in which a small amount of olefin is brought into contact with the olefin polymerization catalyst, and the prepolymerization catalyst Including the above-mentioned [i], [ii] or [iii] polymerized using as a main component of a catalyst for the production of propylene. "Is used in this sense.

  The propylene polymer produced particularly preferably in the present invention is a propylene polymer having a melting peak temperature (Tm) (hereinafter also referred to as melting point) of 105 ° C. or higher and 167 ° C. or lower. If the melting point is significantly lower than the above range, the polymer itself may partially melt at an industrially possible polymerization temperature, making it difficult to maintain stable operation. Among them, a propylene polymer having a temperature of 110 ° C. or higher and 140 ° C. or lower is preferable.

However, the production method of the present invention does not mean that production of a propylene polymer having a melting point other than the melting point is excluded.
Such a low melting point propylene polymer is preferably produced by using a catalyst having a metallocene compound supported on a carrier.
The metallocene catalyst has a narrow crystallinity and molecular weight distribution, and can take advantage of low crystallinity and low molecular weight components, and has excellent low-temperature heat-sealability, which was difficult to produce with conventional Ziegler-Natta catalysts. Polymer can be produced.

When the polymer to be produced is a propylene-ethylene random copolymer, the ethylene content in the copolymer is controlled so that the melting point of the copolymer is preferably in the range of 105 ° C to 140 ° C. Depending on the catalyst used, in the case of a metallocene catalyst, it is generally in the range of 1% by mass to 10% by mass.
In the present invention, the melting peak temperature (Tm) is a value measured by differential scanning calorimetry (DSC). Specifically, for example, using a DSC7 differential scanning calorimeter manufactured by Perkin Elmer, Inc., the sample was heated from room temperature to 230 ° C. under the condition of 80 ° C./min, and held at the same temperature for 10 minutes. It is a peak temperature when the temperature is lowered to 50 ° C. at −10 ° C./min, held at the same temperature for 3 minutes and then melted under a temperature raising condition of 10 ° C./min.

At that time, the gas concentration molar ratio (ethylene / propylene) of ethylene and propylene in the reactor may be adjusted so as to obtain the above melting point, but is preferably 0.01 to 0.5. Preferably, it is in the range of 0.01 to 0.3, more preferably 0.02 to 0.2.
Depending on the purpose, the polymer may be produced using a multistage polymerization method. In that case, about the polymer manufactured at a 1st step, the polymer with said characteristic is preferable, and there is no restriction | limiting in particular about the component of the polymer manufactured after a 2nd step.

The ethylene content in the polymer is determined by NMR. When the multistage polymerization method is used, the polymer polymerized in the first stage is targeted. A specific method is shown below.
i) Measurement of ethylene content by NMR The ethylene content of the obtained polymer is determined by analyzing a 13C-NMR spectrum measured according to the following conditions by a complete proton decoupling method.
Model: GSX-400 manufactured by JEOL Ltd. or equivalent device (carbon nuclear resonance frequency of 100 MHz or more)
Solvent: o-dichlorobenzene: heavy benzene = 4: 1 (volume ratio)
Concentration: 100 mg / ml
Temperature: 130 ° C
Pulse angle: 90 °
Pulse interval: 15 seconds Number of integrations: 5,000 times or more ii) Spectrum Assignment of a spectrum may be performed with reference to Macromolecules, 17, 1950 (1984), for example. The attribution of the spectrum measured on the said conditions is as follows. Symbols such as Sαα represent Carman et al. (Macromolecules, 10, 536 (1977)), P represents a methyl carbon, S represents a methylene carbon, and T represents a methine carbon.

iii) Calculation of ethylene content Hereinafter, when “P” is a propylene unit in a copolymer chain and “E” is an ethylene unit, six types of PPP, PPE, EPE, PEP, PEE, and EEE are included in the chain. There may be a triad. As described in Macromolecules, 15, 1150 (1982), the concentration of these triads and the peak intensity of the spectrum are linked by the following relational expressions (1) to (6).
[PPP] = k × I (Tββ) (1)
[PPE] = k × I (Tβδ) (2)
[EPE] = k × I (Tδδ) (3)
[PEP] = k × I (Sββ) (4)
[PEE] = k × I (Sβδ) (5)
[EEE] = k × {I (Sδδ) / 2 + I (Sγδ) / 4} (6)
Here, [] indicates the fraction of triads, for example, [PPP] is the fraction of PPP triads in all triads. Therefore,
[PPP] + [PPE] + [EPE] + [PEP] + [PEE] + [EEE] = 1 (7)
It is. Further, k is a constant, I indicates the spectral intensity, and for example, I (Tββ) means the intensity of the 28.7 ppm peak attributed to Tββ.

By using the relational expressions (1) to (7) above, the fraction of each triad is obtained, and the ethylene content is obtained from the following expression.
Ethylene content (mol%) = ([PEP] + [PEE] + [EEE]) × 100

  In order to obtain an accurate ethylene content, it is necessary to consider the peak derived from a small amount of propylene heterogeneous bond (2,1-bond and / or 1,3-bond). Since complete separation / identification is difficult and the amount of heterogeneous bonds is small, it is determined using the relational expressions (1) to (7) on the premise that no heterogeneous bonds are included.

The conversion of the ethylene content from mol% to mass% is performed using the following formula.
Ethylene content (mass%) = (28 × X / 100) / {28 × X / 100 + 42 × (1−X / 100)} × 100 where X is the ethylene content in mol%.

  In the present invention, when producing a polymer having a low melting point excellent in transparency and low temperature heat sealability, specifically, a propylene polymer having a melting point of 105 ° C. or higher and 140 ° C. or lower, the effect is particularly remarkable. appear. This is because such a low melting point polymer has a low melting point and is easily melted. In the case of producing such a polymer, a metallocene catalyst having a narrow composition distribution is preferably used.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited only to these examples.
<Method and apparatus for measuring physical properties>
(1) Melt flow rate (MFR)
A polypropylene-type polymer shows the melt index value measured by JIS-K-6758.
(2) Ethylene content in polymer Measured according to the above-mentioned "Measurement of ethylene content by NMR" method.
(3) Polymer melting point (Tm)
Using a DSC7 differential scanning calorimeter manufactured by Perkin Elmer, Inc., the sample was heated from room temperature to 230 ° C. under the condition of 80 ° C./minute, held at that temperature for 10 minutes, and then at −10 ° C./minute. The temperature was lowered to 50 ° C., held at the same temperature for 3 minutes, and then the peak temperature when melted under a temperature rising condition of 10 ° C./min was defined as the melting point (Tm).
(4) Amount of bulk polymer The polymer product was passed through a sieve having a side of a square space of 3,300 μm, and the weight percentage of the powder that did not pass through the sieve was determined.
(5) Long-term drivability When the operation can be continued without reaching 2% by weight even after 1000 hours from the start of operation, the long-term drivability is evaluated as ○, and the amount of bulk polymer is 1000 from the start of operation. When the operation was stopped after reaching 2% by weight in less than the time, the long-term drivability was evaluated as x.
(6) Gas chromatography measurement of composition of liquefied monomer-containing liquid The composition of the liquefied monomer-containing liquid is measured using a process gas chromatography.
The process gas chromatograph used a process gas chromatograph and a column manufactured by Yokogawa Electric Corporation, components other than hydrogen were measured using hydrogen as a carrier gas, and nitrogen was used as a carrier gas for measuring hydrogen. As a detector, measurement was performed with TCD (current 120 mA to 260 mA). The value of gas chromatography was calibrated using standard gas.
In the calculation of the dew point, values normalized using the above values so that the total was 100% were used.

<Example 1>
(1) Production of prepolymerization catalyst 5666 g of distilled water was added to a 10 L glass separable flask equipped with a stirring blade and a reflux device, and 1666 g of 98% sulfuric acid was added dropwise to adjust the internal temperature to 90 ° C. Thereto, 1000 g of montmorillonite (Mizusawa Chemical Co., Ltd. Benclay SL; average particle size = 50 μm) was added and stirred. Thereafter, the reaction was carried out at 90 ° C. for 3.5 hours. The slurry was poured into 5000 mL of distilled water to stop the reaction, filtered through a device in which an aspirator was connected to Nutsche and a suction bottle, and washed with 2500 mL of distilled water. The obtained cake was dispersed in 10,000 mL of distilled water, stirred and filtered. This operation was repeated three times.
The recovered cake was added to an aqueous solution in which 1233 g of zinc sulfate heptahydrate was dissolved in 4500 mL of pure water in a glass separable flask equipped with a 10 L stirring blade, and reacted at room temperature for 2 hours. This slurry was filtered through a device in which an aspirator was connected to Nutsche and a suction bottle, and washed with 2500 mL of distilled water. The obtained cake was dispersed in 10,000 mL of distilled water, stirred and filtered. This operation was repeated three times.
The collected cake was dried at 120 ° C. overnight. As a result, 733 g of a chemically treated product was obtained.
The chemically treated silicate was dried with a kiln dryer.

Preparation of catalyst: 200 g of the dry silicate obtained above was introduced into a 1 L flask and slurried by adding 720 ml of heptane was charged into a 10 L stirred autoclave sufficiently substituted with nitrogen. .
Further, 1280 ml of heptane solution of trinormal octyl aluminum (143.6 mg / ml) was added and stirred at 20 ° C. After 1 hour, it was washed with heptane so that the washing rate was 1/100, and a silicate slurry was prepared to 1000 ml.
Subsequently, 61 ml of a heptane solution of trinormal octyl aluminum (143.6 mg / ml) was added to the silicate slurry, and [(r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4 -Chlorophenyl) -4H-azulenyl}] zirconium] racemate (synthesized according to the example of JP-A-10-226712) 4354 mg (6 mmol) slurried in 600 ml of heptane was added to the silicate slurry, Stir at 60 ° C. for 1 hour.

Preliminary polymerization: Subsequently, 3340 ml of mixed heptane was added to the above stirring autoclave and the temperature was raised to 40 ° C. Then, propylene was supplied at a rate of 100 g / hour, and the temperature was maintained and stirring was continued. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours. After completion of the prepolymerization, the remaining monomer was purged, stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then about 3 liters of the supernatant was decanted. Subsequently, 9.2 ml of a heptane solution of triisobutylaluminum (144.3 g / L) and 5000 ml of heptane were further added, stirred at 38 ° C. for 30 minutes, allowed to stand for 30 minutes, and then 5000 ml of the supernatant was removed. This operation was further repeated 3 times. Subsequently, 167.4 ml of a heptane solution of triisobutylaluminum (144.3 g / L) was added, followed by drying at 40 ° C. under reduced pressure.
By this operation, a prepolymerized catalyst containing 2.1 g of polypropylene per 1 g of catalyst was obtained.
Furthermore, n-hexane was added to the obtained prepolymerized catalyst to prepare a 0.2 wt% catalyst slurry as a catalyst component not containing the prepolymerized polymer.

(2) Polymerization This will be described with reference to the attached flow sheet shown in FIG. Gas phase polymerization was performed using one horizontal polymerization reactor. The horizontal polymerization reactor 10 has a continuous horizontal gas phase polymerization apparatus (length / diameter) equipped with a stirrer having an inner diameter D of 300 mm, a length L of 1540 mm, a diameter of a rotating shaft of 85 mm, and an internal volume of 0.10 m ^3. = 5.13).
Here, the position of the code | symbol 12 (partition 10a) of FIG. 1 was made into the upstream terminal of a reactor.
After replacing the inside of the horizontal polymerization reactor 10 with nitrogen gas, 29 kg of seed powder was introduced, and nitrogen gas was allowed to flow for 3 hours. Thereafter, the temperature was raised while introducing propylene, ethylene and hydrogen, and when the polymerization conditions were completed, the prepolymerized catalyst obtained above from the catalyst component supply pipe 1 installed at a position of 255 mm from the upstream end was solidified. The component was 0.84 g / h, and a 7 wt% n-hexane solution of triisobutylaluminum was continuously supplied at 30 mmol / hr from the catalyst component supply pipe 2 installed at a position of 160 mm from the upstream end of the reactor. . In addition, the ratio of hydrogen concentration in the polymerization vessel 10 and ethylene concentration to propylene concentration is 0.00033 and 0.059, respectively, and thermometers are installed at 160 mm, 330 mm, 690 mm, 855 mm and 1200 mm from the upstream end, respectively, Propylene is supplied so that each temperature is maintained at 59 ° C., 59 ° C., 62 ° C., 64 ° C., 65 ° C., and the polymerization pressure in the horizontal polymerization reactor 10 is maintained at 2.25 MPa. The ethylene monomer was continuously supplied from the raw material supply pipe 4. As shown in FIG. 2, the thermometers 34-1 and 34-2 installed in the zone section (Z1) including the catalyst supply section are respectively the length of the reactor from the upstream end of the reactor. It installed in the position which becomes 1 / 9.62L with respect to L, and 1 / 4.67L. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor was 57.2 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply unit was 59 ° C., and the dew point (Tz) of the mixed gas in the reactor. ) The temperature difference ΔT2 from 57.2 ° C was 1.8 ° C.
Unreacted gas discharged from the horizontal polymerization reactor 10 is extracted out of the reactor system through an unreacted gas extraction pipe 13, cooled and condensed by a recycle drum 11, and supplied as a raw material liquefied propylene supply pipe 19 and a raw material mixed gas supply. The solution was refluxed to the horizontal polymerization reactor 10 through the pipe 18.
The reaction heat was removed by the heat of vaporization of the liquefied monomer-containing liquid supplied from the liquefied monomer-containing liquid supply pipe 19. By controlling the temperature and pressure during operation of the recycle drum 11, the liquefied monomer-containing liquid has a dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid, and the temperature of the polymer particles in the region section including the catalyst supply unit. (Tx) It adjusted so that it might become 59 degreeC or more. Specifically, the temperature of the recycle drum 11 was controlled to 54 ° C. and the pressure to 2.175 MPa, and the composition of the liquefied monomer-containing liquid at that time was as shown in Table 2. The dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid having this composition was 59 ° C. when calculated by the method described above. In addition, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 54.4 kg per hour in the region section including the catalyst supply section.

The propylene-ethylene random copolymer produced in the horizontal polymerization reactor 10 was continuously extracted from the horizontal polymerization reactor 10 through the polymer extraction pipe 21 so that the retained amount of propylene-ethylene random copolymer was maintained at 35 kg. The extracted powder was separated into gases by the gas recovery machine 22, and the powder part was extracted to the powder recovery machine 23.
The production amount per unit time of the propylene-ethylene random copolymer was 9.5 kg / hr, and the catalyst efficiency was 35,000 g-PP / g-Cat.
Table 2 summarizes the measurement results of MFR, ethylene content, and Tm of the obtained propylene-ethylene random copolymer.
The above operation was performed in 1000 hours, and it was confirmed that there was no problem in the long-term stability of the operation. During operation, the mass contained in the polymer withdrawn from the horizontal polymerization reactor 10 was measured every 4 hours by sieving with a 3,300 micron sieve. Table 2 shows the mass after 24 hours and the mass after 1000 hours.

<Example 2>
In Example 1, the feed amount of the prepolymerization catalyst was 1.1 g / h as a solid component, the concentration ratio of hydrogen and propylene was 0.00017, and the operating conditions of the recycling drum were changed as follows. Propylene-ethylene random copolymer was produced in the same manner as in 1. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor was 57.3 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply unit was 59 ° C., and the dew point (Tz) of the mixed gas in the reactor. ) The temperature difference ΔT2 from 57.3 ° C was 1.7 ° C.
When the temperature of the recycle drum was controlled to 52.79 ° C. and the pressure to 2.163 MPa, the composition of the liquefied monomer-containing liquid was as shown in Table 2. It was 60.8 degreeC when the dew point (Tq) in the polymerization pressure of the mixed gas of the composition of the liquefied monomer containing liquid of this composition was computed by the above-mentioned method. In addition, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 53.5 kg per hour in the region section including the catalyst supply unit.
The production amount per unit time of the propylene-ethylene random copolymer was 9.4 kg / hr, and the catalyst efficiency was 26,420 g-PP / g-Cat.
Table 2 summarizes the MFR, ethylene content, Tm measurement results, and long-term stability evaluation results of the resulting propylene-ethylene random copolymer.

<Example 3>
In Example 1, the feed rate of the prepolymerized catalyst was 1.25 g / h as a solid component, the hydrogen / propylene concentration ratio was 0.00018, and the operating conditions of the recycle drum were changed as follows. Propylene-ethylene random copolymer was produced in the same manner as in 1. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor was 58.7 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply unit was 59 ° C., and the dew point (Tz) of the mixed gas in the reactor. ) The temperature difference ΔT2 from 58.7 ° C. was 0.3 ° C.
When the temperature of the recycle drum was controlled to 53.53 ° C. and the pressure to 2.150 MPa, the composition of the liquefied monomer-containing liquid was as shown in Table 2. It was 62 degreeC when the dew point (Tq) in the polymerization pressure of the mixed gas of the composition of the liquid monomer containing liquid of this composition was computed by the method as mentioned above. Further, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 52.2 kg per hour in the region section including the catalyst supply unit.
The production amount per unit time of the propylene-ethylene random copolymer was 9.3 kg / hr, and the catalyst efficiency was 22,900 g-PP / g-Cat.
Table 2 summarizes the MFR, ethylene content, Tm measurement results, and long-term stability evaluation results of the resulting propylene-ethylene random copolymer.

<Example 4>
In Example 1, the feed amount of the prepolymerization catalyst was 0.87 g / h as a solid component, and the ratio of hydrogen concentration in the polymerization vessel 10 and ethylene concentration to propylene concentration was 0.00040 and 0.055, respectively. To 55.5 ° C., 55.5 ° C., 55.5 ° C., 56.5 ° C. and 56.5 ° C. from the upstream, respectively, and propylene was added so that the polymerization pressure in the horizontal polymerization reactor 10 was maintained at 2.1 MPa. Hydrogen and ethylene monomer were continuously supplied from the raw material supply pipe 4, and n-hexane was supplied to the recycling drum at 85.5 mL / h, and the operating conditions of the recycling drum were changed as follows. Except for the above, a propylene-ethylene random copolymer was produced in the same manner as in Example 1. In addition, the installation position of the thermometer installed in a catalyst supply part and the area | region division containing a catalyst supply part is the same as Example 1. FIG. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor is 50.1 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply section is 55.5 ° C., and the dew point of the mixed gas in the reactor The temperature difference ΔT2 from (Tz) 50.1 ° C. was 5.4 ° C.
When the temperature of the recycle drum was controlled at 46.5 ° C. and the pressure at 2.1 MPa, the composition of the liquefied monomer-containing liquid was as shown in Table 2. It was 61.7 degreeC when the dew point (Tq) in the superposition | polymerization pressure of the mixed gas of the composition of the liquid monomer containing liquid of this composition was computed by the above-mentioned method. Further, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 38.9 kg per hour in the region section including the catalyst supply section.
The production amount per unit time of the propylene-ethylene random copolymer was 7.7 kg / hr, and the catalyst efficiency was 27,500 g-PP / g-Cat.
Table 2 summarizes the MFR, ethylene content, Tm measurement results, and long-term stability evaluation results of the resulting propylene-ethylene random copolymer.

<Example 5>
In Example 1, the feed amount of the pre-polymerization catalyst was 1.72 g / h as a solid component, the hydrogen concentration in the polymerization vessel 10 and the ratio of ethylene concentration to propylene concentration were 0.00019 and 0.051, respectively, To 58 ° C., 58 ° C., 58 ° C., 59 ° C. and 59 ° C. from the upstream, respectively, and propylene is supplied so that the polymerization pressure in the horizontal polymerization reactor 10 is maintained at 2.1 MPa. Propylene was produced in the same manner as in Example 1 except that it was continuously supplied from the raw material supply pipe 4 and n-hexane was supplied to the recycle drum at 169 mL / h, and the operation conditions of the recycle drum were changed as follows. -An ethylene random copolymer was produced. In addition, the installation position of the thermometer installed in a catalyst supply part and the area | region division containing a catalyst supply part is the same as Example 1. FIG. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor is 52.8 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply unit is 58 ° C., and the dew point (Tz) of the mixed gas in the reactor. ) The temperature difference ΔT2 with respect to 52.8 ° C was 5.2 ° C.
When the temperature of the recycling drum was controlled to 43.7 ° C. and the pressure was controlled to 2.1 MPa, the composition of the liquefied monomer-containing liquid was as shown in Table 2. The dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid having this composition was calculated by the method as described above and found to be 69 ° C. Further, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 62.6 kg per hour in the region section including the catalyst supply section.
The production amount per unit time of the propylene-ethylene random copolymer was 10.3 kg / hr, and the catalyst efficiency was 18,540 g-PP / g-Cat.
Table 2 summarizes the MFR, ethylene content, Tm measurement results, and long-term stability evaluation results of the resulting propylene-ethylene random copolymer.

<Comparative Example 1>
In Example 1, the feed amount of the prepolymerization catalyst was 0.89 g / h as a solid component, and the ratio of hydrogen concentration in the polymerization vessel 10 and ethylene concentration to propylene concentration was 0.00034 and 0.058, respectively. Is supplied from the upstream so that 55.5 ° C, 55.5 ° C, 55.5 ° C, 56.5 ° C, 56.5 ° C, and the polymerization pressure in the horizontal polymerization reactor 10 is maintained at 2.1 MPa. In addition, hydrogen and ethylene monomer were continuously supplied from the raw material supply pipe 4, and n-hexane was supplied to the recycling drum at 59.9 mL / h, and the operating conditions of the recycling drum were changed as follows. Produced a propylene-ethylene random copolymer in the same manner as in Example 1. In addition, the installation position of the thermometer installed in a catalyst supply part and the area | region division containing a catalyst supply part is the same as Example 1. FIG. Table 2 shows the composition of the mixed gas in the reactor. At this time, the dew point (Tz) of the mixed gas in the reactor was 51.7 ° C., the temperature (Tx) of the polymer particles in the region including the catalyst supply unit was 55.5 ° C., and the dew point of the mixed gas in the reactor The temperature difference ΔT2 from (Tz) 51.7 ° C. was 3.8 ° C.
When the temperature of the recycle drum was controlled at 48.01 ° C. and the pressure at 2.1 MPa, the composition of the liquefied monomer-containing liquid was as shown in Table 2. It was 54 degreeC when the dew point (Tq) in the polymerization pressure of the mixed gas of the composition of the liquid monomer containing liquid of this composition was computed by the above-mentioned method. Further, the liquefied monomer-containing liquid was supplied from the liquefied monomer-containing liquid supply pipe 19 at a rate of 59 kg per hour in the region section including the catalyst supply section.
The production amount per unit time of the propylene-ethylene random copolymer was 10.0 kg / hr, and the catalyst efficiency was 35,000 g-PP / g-Cat.
Table 2 summarizes the measurement results of MFR, ethylene content, and Tm of the obtained propylene-ethylene random copolymer.
During operation, the amount of lump contained in the polymer withdrawn from the horizontal polymerization reactor 10 was measured every 4 hours by sieving with a 3,300 micron sieve. The amount of lump after 66 hours became 2% by weight and the operation was stopped.

<Consideration by contrast between Example and Comparative Example>
In Comparative Example 1, as a prior art example, as in Patent Document 8, the temperature difference ΔT2 (° C.) between the temperature (Tx) of the section including the catalyst supply unit and the dew point (Tz) of the mixed gas in the reactor is used. = Tx−Tz) is set to satisfy 0 to 5 ° C.
According to a comparison between Examples 1 to 5 and Comparative Example 1, the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid was determined as the temperature (Tx) of the polymer particles in the region segment including the catalyst supply unit It has been clarified that by setting the above, the amount of the bulk polymer does not reach 2% by weight even after 1000 hours from the start of operation, and can maintain a particularly long operation stability compared to the prior art.

1 Catalyst component supply piping 2 Catalyst component supply piping 3 Raw material monomer supply piping 4 Raw material supply piping (hydrogen etc.)
5, 6 Piping 10 Horizontal polymerization reactor 10a, 10b Partition wall 11 Recycle drum 12 Reactor upstream end 13 Unreacted gas extraction piping
14 Reactor downstream end 15 Condenser
16 Compressor 18, 18-1, 18-2, 18-3, 18-4, 18-5 Raw material mixed gas supply piping 19, 19-1, 19-2, 19-3, 19-4, 19-5 Liquefied monomer-containing liquid supply pipe 20 Stirrer 20a Horizontal shaft 20b Stirring blade 21 Polymer extraction pipe
22 Gas recovery machine 23 Powder recovery machine 30 Horizontal polymerization reactor
31 catalyst component supply pipe 32 partition 33 partition
34-1, 34-2, 34-3, 34-3,... 34-i thermometer 35 horizontal axis

Claims (4)

A process for producing a propylene polymer by polymerizing propylene or propylene and an α-olefin excluding propylene in the presence of a catalyst by a continuous polymerization method in which the heat of reaction is removed by the heat of vaporization of the liquefied monomer-containing liquid. ,
Using a reactor that can set multiple zone sections with different temperatures in the longitudinal direction inside,
The propylene-based weight is characterized in that the dew point (Tq) at the polymerization pressure of the mixed gas having the composition of the liquefied monomer-containing liquid is set to be equal to or higher than the temperature (Tx) of the polymer particles in the region section including the catalyst supply unit. Manufacturing method of coalescence. Α-olefin excluding propylene or propylene and propylene by a continuous gas phase polymerization method using a horizontal polymerization reactor equipped with a stirrer rotating around a horizontal axis and removing reaction heat by the heat of vaporization of the liquid containing the liquefied monomer In the presence of a catalyst to produce a propylene polymer,
The method for producing a propylene-based polymer according to claim 1, wherein the reactor is capable of setting a plurality of region sections having different temperatures in the horizontal axis direction.   3. The method for producing a propylene-based polymer according to claim 1, wherein the temperature (Tx) of the region section including the catalyst supply unit is 50 ° C. or more and 65 ° C. or less.   At least one selected from saturated hydrocarbons having 6 to 7 carbon atoms is set such that the dew point (Tq) of the gas of the composition of the liquefied monomer-containing liquid is equal to or higher than the temperature (Tx) of the region section including the catalyst supply unit. The method for producing a propylene-based polymer according to any one of claims 1 to 3, wherein the propylene-based polymer is added in a sufficient amount.