JPH06220117A - Production of (co)polymer of ethylene having wide molecular weight distribution - Google Patents

Abstract

PURPOSE: To obtain efficiently ethylene polymers having a extensive mol.wt. distribution by the use of slid components supported by halogenated Mg, having Ti-halogen bonds and specific surface area and total porosity and catalysts consisting of organic Al compounds.

CONSTITUTION: The objective copolymers having an extensive mol.wt. distribution and containing up to 20% of α-olefins expressed by the formula; CH₂=CHR (R is a 1-10C hydrocarbon) are obtained by the copolymerization of ethylene and the α-olefins using catalysts consisting of reaction products of (A) spherical solid components which are supported on halogenated magnesium, contain at least one Ti-halogen bonds, consist of titanium compounds having optionally ≤3 mol.wt. of groups different from halogens, have specific surface area of ≤70 m²/g determined by BET Method, total porosity of ≥0.5 cm³/g determined by mercury method and at least 50% of them have porosity diameter of ≥800 Å, with (B) Al-alkyl compounds.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention contains up to 20 mol% of homopolymers having a wide molecular weight distribution (MWD) and α-olefin CH ₂ ═CHR (R is a hydrocarbon group having 1 to 10 carbon atoms). It relates to a manufacturing method for synthesizing copolymers of ethylene.

[0002]

The polymerization involves the presence of a catalyst consisting of the reaction product of an Al-alkyl and a solid catalyst component consisting of a titanium compound supported on a magnesium halide characterized by a spherical morphology and grain surface. It is done by. According to the process of this invention, ASTM
21.6, defined by D-1238 at 190 ° C
Melt index (melt index F) measured with a load of kg and melt index (melt index E) measured with a load of 2.16 kg
80 units derived from ethylene, characterized by a high melt flow ratio (F / E) value expressed as the ratio
Ethylene homopolymers and copolymers containing more than mol% can be synthesized. This F / E ratio is generally considered as an index of the width of the molecular weight distribution.

MWD is a particularly important property of ethylene (co) polymers and affects both the rheological behavior and, consequently, the processability and ultimate mechanical properties of the melt. Polyolefins having a broad MWD, especially those bound with relatively high average molecular weight, are preferably subjected to high speed extrusion and blow molding under conditions where a narrow MWD causes melt fracture.

It is known to obtain a wide range of MWD by a multi-step method of producing polymer fractions of different molecular weights in a single step in which macromolecules of different length are sequentially formed on the catalyst particles. The molecular weight obtained at each stage can be controlled by different methods, for example, by changing the polymerization conditions or the catalyst system in each step, or by using a molecular weight modifier. Adjustment with hydrogen
The preferred method is to perform either in solution or in the gas phase.

A general problem known in this type of process is that it does not lead to a sufficiently homogeneous product, especially in the case of very broad molecular weight distributions. High F / E ratio, eg 1
Obtaining a product having a value of 00 or higher is practically difficult and when subjected to the conversion step results in a product free of unmelted particles. A solution to this problem is disclosed in Japanese Patent Application No. 5-1464 in the name of the applicant of the present invention, which relates to an apparatus and a method for producing an olefin (co) polymer showing a wide range of MWD.
No. 85, that is, polymers having a high F / E ratio and a high homogeneity composition are produced in the gas phase in two or more reactors with polymer recycling between the reactors. Obtained by the continuous method.

Ethylene polymers and copolymers having a broad molecular weight distribution when the polymerization process is carried out in the presence of a catalyst prepared by using a solid component containing titanium supported on activated magnesium chloride. It was surprisingly found that the kind can be manufactured.
Solid components are characterized by spherical morphology and special surface and porosity properties.

In the method of the present invention, ethylene or a mixture of ethylene and α-olefins CH ₂ ═CHR (wherein R is a hydrocarbon group having 1 to 10 carbon atoms); Supported by magnesium, 1 or more T
It comprises a titanium compound containing an i-halogen bond and optionally containing a group different from halogen in an amount of 0.3 mol or less per mol of titanium, having a surface area of 7 as measured by the BET method.
0 m ² / g or less, total porosity (total por
the presence of a catalyst consisting of a reaction product of (B) an Al-alkyl compound, and a solid component in the form of spheres having an osity of 0.5 cm ³ / g or more and at least 50% of the pore radius having a value greater than 800Å. Polymerize in.

Preferred Al-alkyl compounds are, for example, Al-trimethyl, Al-triethyl or Al-.
Al-trialkyl such as triisobutyl. The preferred component (A) has a porosity between 0.6 and 0.9 cm ³ / g and a surface area between 40 and 60 m ² / g.
The titanium compound is preferably TiCl ₄ or TiCl ₃ .

The solid component particles are substantially spherical in shape and have an average diameter of 5 to 150 μm. For particles having a substantially spherical morphology, it is meant that the ratio of the major axis to the minor axis is equal to or less than 1.5, preferably less than 1.3. Magnesium dihalide constituting the spherical component of the present invention is in the active form, and the strongest line appearing in the spectrum of the inactive halide in the X-ray spectrum decreases in intensity, and the maximum intensity shifts to a lower angle than that of the strongest line. The feature is that it is replaced with halo.

The magnesium dihalide is preferably MgCl ₂ . The spherical component used in the method of the present invention is (I) MgCl ₂ · mROH compound (0 ≦ m ≦ 0.5,
R is an alkyl, cycloalkyl or aryl group having 1 to 12 carbon atoms and (II) titanium compound Ti (OR) _n X _yn (n is 0 to 0.3 including both ends, y is titanium value, X is halogen) , R can be suitably produced by a process consisting of a reaction with an alkyl having 2 to 8 carbons, or a COR group).

In this step, the compound (I) was added to the adduct MgCl ₂ · qROH (2.5 ≦ q ≦ 3.5) by thermal dealcoholation to obtain the adduct MgCl ₂ · pROH (0.
Made by chemical dealcoholation of 1 ≦ p ≦ 2). By the reaction of compound (II) and compound (I), the molar ratio Ti / Mg
Is 3 or more. The adduct MgCl ₂ · qROH is made spherical by suspending the molten adduct in liquid hydrocarbons and then quenching to solidify. A representative example of a method for making this spherical adduct is described in US Pat. No. 4,469,648, the description of which is incorporated herein by reference.
Other possible methods of spheronization include spray cooling as described in US Pat. Nos. 5,100,849 and 4,829,034, which descriptions are also incorporated herein by reference. The spheroidized adduct thus obtained is at a temperature of 50 to 150 ° C. until the alcohol content is reduced to a value of 2 mol or less, preferably 1.5 to 0.3 mol, per mol of magnesium dihalide. Subject to thermal dealcoholization, until the alcohol content is usually 0.5 mol or less,
Dealcohol is treated with a chemical reagent capable of reacting with the OH groups of the alcohol.

The treatment with the chemical dealcoholating agent is carried out with a sufficient amount of agent to react with the OH present in the adduct alcohol. It is preferred to use a small excess of the agent, which is separated before the reaction of the support obtained after the treatment with the titanium compound. Examples of chemical dealcoholating _{agents, Al (C 2 H 5)} 3, Al (C 2 H 5) 2 Cl, Al (i
-Bu) ₃ Al-alkyl compounds, SiCl ₄ ,
Mention may be made of halogenated Si or Sn compounds such as SnCl ₄ .

The preferred titanium compound (II) is titanium tetrahalide, especially TiCl ₄ . In this case, the compound obtained after chemical dealcoholation has an excess of T
Suspend in iCl ₄ . The suspension is then 80-135 ° C.
It is heated at the temperature of and kept at this temperature for 0.5 to 2 hours. Excess titanium is filtered at high temperature, or separated by settling and siphoning (at high temperature). The treatment with TiCl ₄ can be arbitrarily performed multiple times.

When the titanium compound is a solid such as TiCl ₃ , it can be dissolved in the molten adduct of the raw material and supported on the magnesium halide. Adduct MgC
If the chemical dealcoholation of l ₂ .pROH is carried out with an agent capable of reducing alcohol, for example with an Al-alkyl compound such as Al-triethyl, the compound obtained is a titanium compound before reaction with the titanium compound. In order to avoid the reduction of ## STR1 ## and optionally for the inactivation of Al-triethyl, it can be treated with an inactivating agent such as O ₂ or an alcohol.

Treatment with a deactivator is avoided when it is desired to at least partially reduce the titanium compound.
On the contrary, when more reduction of the titanium compound is desired, the preparation of this component can be advantageously carried out by the use of a reducing agent.
Examples of the reducing agent include, for example, Al-trialkyls,
Al-alkyls such as Al-alkyl halides,
Silicon compounds such as polyhydrosiloxanes may be mentioned.

The polymerization step of the present invention can be carried out in a liquid phase or a gas phase, for example, under the condition of mechanically stirring a known fluidized bed or polymer. It is preferred to carry out the process in the gas phase. Hydrogen is preferred as the molecular weight regulator. Working in a single stage also makes it possible to obtain polymers with F / E ratios higher than 90-100 and excellent homogeneous compositions. The MWD can be broader if the polymerization is carried out in multiple stages operating at different molecular weight regulator concentrations.

If the polymerization is carried out in the gas phase in one or more reactors, the process of the invention is suitably carried out by the steps shown below: (a) In the absence of polymerizable olefins, Or optionally a contacting step with the catalyst component in the presence of said olefin in an amount of less than 20 g / g of solid component (A); (b) ethylene or a mixture of one or more ethylene and α-olefins, ie The mixture contains up to 20 mol% of α-olefin and is about 30 per 1 g of the solid component (A).
A polymerization step to form a polymer in an amount of about 1000 g; (c) in one or more fluidized bed or mechanically stirred bed reactors, using the prepolymer catalyst system resulting from (b),
An alkane having a carbon number of 3 to 5 which is present at a concentration of 20 to 90 mol% with respect to the total gas is circulated through a reactor, and ethylene or ethylene and α-olefin CH ₂ ═CHR
A gas phase polymerization step of a mixture with (wherein R is a hydrocarbon group having 1 to 10 carbon atoms).

In the prepolymerization stage (b) it is preferred to produce 100 to 400 g of polymer per gram of solid component (A). The alkane is preferably propane. In step (b), insoluble in xylene at 60% or more, preferably 90% or more, of the amount stated above, with a mixture of prepolymerized propylene or ethylene and / or α-olefin CH ₂ ═CHR. It is also possible to obtain certain propylene polymers. In this case, the catalyst may, as is known, comprise an internal electron-donating compound and optionally an external electron-donor in order to be able to produce polymers exhibiting the desired properties.

In order to improve the quality of the product, the process according to the invention is carried out in two reactors under different conditions, at least part of the polymer formed in the second reactor, the first reaction. It can be preformed by recycling to the vessel. The process of this invention is a high density ethylene polymer (HDP) consisting of an ethylene homopolymer and a copolymer of ethylene and an alpha olefin having 3 to 12 carbon atoms.
E, a density of 0.940 g / cc or more); a linear low density polyethylene comprising a copolymer of ethylene having a molar content of ethylene-derived units of 80% or more and one or more alpha olefins (having 3 to 12 carbon atoms). (LLDPE,
0.940g / cc or less), and very low density polyethylene and ultra low density polyethylene (VLDPE and UL
DPE, density of 0.920 g / cc to 0.880 g / cc or less) is suitable for production.

The production of HDPE, in which the width of the molecular weight distribution is particularly important, is the preferred production. The invention will now be illustrated by the examples, without being limited thereby. Properties are measured by the following methods. The nitrogen porosity and surface area are
B. E. It is measured by the T method (using SORPTOMATIC 1900 manufactured by Carlo Erba Co.).

For porosity and surface area with mercury, a known amount of mercury is immersed in a dilatometer, and then the mercury pressure is gradually increased to 2000 kg / cm ² with a hydraulic pump. The introduction pressure of mercury into the pore depends on the diameter of the pore itself. The measurement is performed using the POROSIMETER 2000 series, a porosimeter manufactured by Carlo Erba. The porosity, pore distribution and surface area are calculated from the volume reduction data of mercury and applied pressure values.

The size of the catalyst particles is determined by "Malvern Instr. 2
Using the apparatus 600 ", is measured by the method according to the principle of the laser monochromatic light diffraction MIE flow index:. ASTM-D 1238 MIF flow index: ASTM-D 1238 Liquidity: polymer 100g is, the diameter of 1.25cm Time taken to flow against a 20 ° vertical wall with a funnel with an exit hole.

Bulk Density : DIN-53194 Polymer Particle Morphology and Particle Size Distribution : ASTM-D192
1-63 xylene dissolved fraction : measured at 25 ° C. comonomer content :% by weight of comonomer measured by IR spectrum effective density : ASTM-D 792

[0024]

Example: Synthesis of spherical support (MgCl ₂ / EtOH adduct) The adduct of magnesium chloride and alcohol is 10000.
Synthesized by the method described in Example 2 of US Pat. No. 4,399,054 except operating at 200 RPM instead of RPM. The adduct containing about 3 mol of alcohol had an average size of about 60 μm, and its distribution width was 30 to 90 μm.

Example 1 Synthesis of solid components Spherical particles composed of about 35% residual alcohol (1.1 mol of alcohol per 1 mol of MgCl ₂ ) were added to a spherical support prepared by heat treatment by a general method. Until obtained, heat treatment was performed under a nitrogen stream in a temperature range of 50 to 150 ° C. under a nitrogen stream.

2700 g of this support was transferred to a 60 liter autoclave together with 38 liters of anhydrous hexane. 100 g / L AlE at room temperature with stirring
11.6 L of hexane solution containing t ₃ was added over 60 minutes. The temperature was raised to 50 ° C. over 60 minutes and kept at this temperature for another 30 minutes with stirring. The liquid phase was removed by filtration; the treatment with AlEt ₃ was repeated twice under the same conditions. The spherical product obtained was washed 3 times with anhydrous hexane and dried at 50 ° C. under vacuum.

The characteristics of the support thus obtained are given below: Porosity (Hg) 1.144 g / cm ³ Surface area (Hg) 15.2 m ² / g Residual OEt 5.5 (% by weight) ) Residual Al 3.6 (wt%) Mg 20.4 (wt%)

Into a 72 liter steel reactor equipped with a stirrer was introduced 40 liters of TiCl ₄ ; at room temperature, 1900 g of the above support was introduced with stirring.
The whole was heated to 100 ° C. over 60 minutes and kept in this state for another 60 minutes. The stirring was discontinued and after 30 minutes the liquid phase was separated from the precipitate. Only the first heat treatment at 120 ° C. and the second heat treatment at 135 ° C. were different, and two more treatments were performed under the same conditions. Then 60
Washing was performed with anhydrous hexane (about 19 liters) three times at a temperature of three times and four times at room temperature. After drying under vacuum at 50 ° C., 2400 g of spherical components were obtained. The characteristics are shown below: Total titanium 6 (wt%) Ti ^III 4.9 (wt%) Al 3 (wt%) Mg 12.2 (wt%) Cl 68.2 (wt%) OEt 0.3 (Wt%) Porosity (BET) 0.208 cm ³ /
g, 50% of them have holes with a radius of 300 Å or more.

Surface Area (BET) 56.2 m ² / g Total Porosity (Hg) 0.674 cm ³ /
g, 50% of which have holes with a radius of 1250Å or more. Surface area (Hg) 21 m ² / g Polymerization of ethylene (HDPE) In a 2.4 liter stainless steel autoclave degassed at 70 ° C. under a nitrogen stream, 2000 cc of anhydrous hexane, 0.0095 g of spherical components and 0 are added. 0.5 g
Of Al-triisobutyl was introduced. Stir the whole, 7
It was heated to 5 ° C. and then fed with 4 bar H ₂ and 7 bar ethylene. The polymerization was carried out for 3 hours, during which the ethylene pressure was kept constant.

350 g of polymer were obtained having the following characteristics: MIE 0.12 g / 10 min MIF / MIE 120 effective density 0.960 g / cm ³ bulk density 0.32 g / cm ³ flowability 11 sec shape spherical P. S. D. > 4000μm 0.6 (wt%) 2000-4000μm 87.8 (wt%) 1000-2000μm 11 (wt%) 500-1000μm 0.3 (wt%) <500μm 0.3 (wt%)

EXAMPLE 2 0.5 g of the same autoclave as in Example 1 was added at 30 ° C.
Provide Al-triisobutyl and 0.0122 g of spherical component.
After feeding, 7 bar ethylene and 4 bar H ₂Supply
did. Add about 5 g of ethylene at 30 ° C until the system absorbs.
Maintained its state. Then heat the whole to 75 ° C and
Feed ethylene for 3 hours to maintain a constant pressure.
I put them together. 290 g of polymer having the following characteristics
Was obtained: MIE 0.15 g / 10 minutes MIF / MIE 120 bulk density 0.36 g / cm³ Flowability 11 seconds Shape Spherical P. S. D. > 4000μm 0.1 (wt%) 2000-4000μm 69.7 (wt%) 1000-2000μm 29.3 (wt%) 500-1000μm 0.4 (wt%) <500μm 0.5 (wt%)

Example 3 80 g of the support obtained according to Example 1 was treated with AlEt ₃
And was treated with dry air in a fluidized bed at 40 ° C. for about 4 hours. After this treatment, the support was fed into the reactor with 800 cc of TiCl ₄ kept at room temperature. With thorough stirring, the mixture was slowly heated to 100 ° C. and then maintained for 60 minutes. After stirring was stopped and a solid was deposited for decanting, the liquid phase was separated by suction. Only the first heat treatment at 120 ° C. and the second heat treatment at 135 ° C. were different, and two more treatments were performed under the same conditions. After that, 3 times at 60 ℃,
Washing was performed with anhydrous hexane having a concentration of about 100 g / liter for seven times at room temperature four times in total. The spherical components were dried under vacuum at 50 ° C. and characterized as follows: Total Titanium 3.1 (wt%) Ti ^III <0.1 (wt%) Mg 19.1 (wt%) Cl 67.9 (Wt%) Residual OEt 0.6 (wt%) Al 3.5 (wt%)

Porosity (BET) 0.15
5 cm ³ / g, of which 50% have pores with a radius of 300 Å or more. Surface area (BET) 57.8 m ² / g Total porosity (Hg) 0.751 cm ³ /
g, 50% of which have holes with a radius of 1600Å or more. 90% have pores of 15,000Å or more. Surface Area (Hg) 26.8 m ² / g Polymerization of Ethylene (HDPE) 0.0106 g of sphere-forming components were used for the polymerization of ethylene under the same conditions as described in Example 1.

380 g of polymer were obtained which were characterized as follows: MIE 0.565 g / 10 min MIF / MIE 90 bulk density 0.34 g / cc shape spherical flowability 12 seconds P.I. S. D. > 4000μm 0.3 (wt%) 2000 to 4000μm 85.3 (wt%) 1000 to 2000μm 13.7 (wt%) 500 to 1000μm 0.5 (wt%) <500μm 0.1 (wt%)

[0035]

According to the present invention, a broad molecular weight distribution can be obtained by carrying out the polymerization step in the presence of a catalyst prepared by using a solid component containing titanium supported on activated magnesium chloride. Ethylene polymers and copolymers having can be prepared.

Front Page Continuation (72) Inventor Gianni Pennini Italy, 44044 Poroti (FE), Via Ballot 23

Claims (20)

[Claims] 1. (A) Titanium supported on magnesium halide, containing one or more Ti-halogen bonds, and optionally containing groups different from halogen in an amount of 0.3 mol or less per mol of titanium. It is composed of a compound and has a surface area of 70 m ² / g or less as measured by the BET method, a total porosity of 0.5 cm ³ / g or more as measured by the mercury method, and a pore radius of at least 50% from 800 Å Ethylene homopolymers and α-olefins CH ₂ ═CHR having a broad molecular weight distribution using a catalyst composed of a reaction product of (B) an Al-alkyl compound and a spherical component having a large value A method for producing ethylene copolymers containing up to 20 mol% (wherein R is a hydrocarbon group having 1 to 10 carbon atoms). 2. The solid component (A) has a porosity of 0.6 to 0.
The method according to claim 1, wherein the surface area is 9 cm ³ / g and the surface area is 40 to 60 m ² / g. 3. The titanium compound present in the solid component is
Method according to claim 1 or 2 selected from TiCl ₄ and TiCl ₃ . 4. The method of claim 1, wherein the Al-alkyl compound is Al-trialkyl. 5. The component (A) is (I) a MgCl ₂ .mROH compound (0 ≦ m ≦ 0.5,
R is an alkyl, cycloalkyl or aryl group having 1 to 12 carbon atoms and (II) titanium compound Ti (OR) _n X _yn (n is 0 to 0.3 including both ends, y is titanium value, X is halogen) , R is an alkyl group having 2 to 8 carbon atoms, or a COR group), and the compound (I) is an adduct Mg.
Adduct MgCl ₂ · pROH (0.1 ≦ p) obtained by thermal dealcoholization of Cl ₂ · qROH (2.5 ≦ q ≦ 3.5)
The method according to claim 1, which is produced by the chemical dealcoholation of ≤2) and the molar ratio Ti / Mg of the reaction of the compound (II) and the compound (I) is 3 or more. 6. The method according to claim 5, wherein the titanium compound (II) is TiCl ₄ . 7. The method according to claim 5, wherein the titanium compound (II) is TiCl ₄ and the reaction of the compound (I) with the compound (II) is carried out in TiCl ₄ . 8. The method according to claim 1, wherein the polymerization is carried out in the gas phase. 9. The process according to claim 1, wherein the polymerization is carried out in a single reactor to obtain a polymer having an F / E ratio of 90 or higher. 10. The method according to claim 8, wherein the polymerization is carried out in a single reactor to obtain a polymer having an F / E ratio of 90 or more. 11. The process according to claim 1, wherein the polymerization is carried out under different conditions by operating two or more reactors. 12. The process according to claim 1, wherein the polymerization is carried out by operating two or more reactors under different concentrations of the molecular weight regulator. 13. The molecular weight modifier is hydrogen.
2. The method described in 2. 14. The method of claim 13, wherein the polymerization is carried out in the gas phase.
The method described. 15. The step of contacting the polymerization with a catalyst component in the presence of (a) a polymerizable olefin in the absence or optionally in the presence of less than 20 g of said olefin per gram of solid component (A). (B) ethylene or a mixture of one or more ethylene and α-olefins, the mixture containing up to 20 mol% of α-olefin, and about 30 to about 1 per 1 g of the solid component (A).
A polymerization step to form a polymer in an amount of 000 g; (c) in one or more fluidized bed or mechanically stirred bed reactors, using the prepolymer catalyst system resulting from (b),
An alkane having a carbon number of 3 to 5 which is present at a concentration of 20 to 90 mol% with respect to the total gas is circulated through a reactor, and ethylene or ethylene and α-olefin CH ₂ ═CHR
9. The method according to claim 8, which is carried out by a gas phase polymerization step of a mixture with (wherein R is a hydrocarbon group having 1 to 10 carbon atoms) mixture. 16. About 10 g per 1 g of the solid component (a).
The method of claim 15, wherein 0 to about 400 g of polymer is produced in polymerization stage (b). 17. The alkane is propane.
The method according to 5. 18. The method according to claim 17, wherein the polymerization is carried out in two or more steps with different hydrogen concentrations. 19. The method of claim 8 wherein the polymerization is conducted in two reactors conducted at different conditions and the polymer formed in the second reactor is at least partially recycled to the first reactor. 20. The method according to any one of the preceding claims, wherein a high density polyethylene is produced.