WO2007119936A1

WO2007119936A1 - Method for polymerization and copolymerization of olefin

Info

Publication number: WO2007119936A1
Application number: PCT/KR2007/001453
Authority: WO
Inventors: Jae-Hyuck Han; Ho-Sik Chang; Chun-Byung Yang
Original assignee: Samsung Total Petrochemicals Co., Ltd.
Priority date: 2006-04-19
Filing date: 2007-03-26
Publication date: 2007-10-25
Also published as: KR100723366B1

Abstract

Disclosed is a method for polymerization and copolymerization of olefin characterized by polymerizing or copolymerizing olefins in the presence of: (A) a prepolymerized catalyst obtained by prepolymerizing olefins in the presence of (a) a solid complex titanium catalyst prepared by the following steps, (b) an aluminum alkyl and (c) an electron donor, wherein the steps comprises: (i) preparing a magnesium compound solution by dissolving a magnesium halide compound into an oxygen - containing solvent mixture of a cyclic ether and one or more alcohols; (ii) preparing a carrier by firstly reacting the resulted magnesium compound solution with a titanium halide compound at -10 -30oC, elevating the temperature or aging the resulted product to obtain particles, and secondly reacting the resulted product with a titanium halide compound; (iii) preparing a titanium catalyst by reacting the obtained carrier with a titanium halide compound and an electron donor; and (iv) washing the resulted catalyst with a hydrocarbon solvent at 40 - 200oC; (B) an organometallic compound from Group II or III of Periodic table of elements; and (C) an external electron donor. The method for polymerization and copolymerization of olefin can provide olefin polymers having high stereoregularity, enhanced polymerization activity and improved productivity in a polymerization process.

Description

Description METHOD FOR POLYMERIZATION AND COPOLY-

MERIZATION OF OLEFIN

Technical Field

[1] The present invention relates to a method for polymerization and copolymerization of olefin, specifically to a method for polymerization and copolymerization of olefin using a prepolymerized catalyst obtained by prepolymerizing olefins with a solid complex titanium catalyst at low temperature under low pressure. Background Art

[2] Many catalysts for polymerization of olefin and polymerization methods using the same have been reported so far. However, there still have been needs for more efforts to: improve physical properties of the resulted polymers by using a catalyst invented to have more improved commercial qualities; thus raise productivity; or enhance the product quality, and many demands for improvement in the activity and stereo- regularity of a catalyst itself.

[3] Magnesium - containing and titanium - based catalysts for polymerization of olefin, and methods for producing such catalysts have been reported many. Particularly, methods for preparing a catalyst using a magnesium compound solution have been well known in the art, in order to adjust the shape, size or the like of the catalyst.

[4] For example, there is a method for obtaining a magnesium solution by reacting a magnesium compound with an electron donor such as alcohols, amines, ethers, esters, carboxylic acids and the like, in the presence of a hydrocarbon solvent. Methods using alcohols are disclosed in US patent Nos. 4,330,649 and 5,106,807, and Japanese laid - open patent publication Sho 58-83006. Further, methods for preparing a magnesium solution are also reported in US patent Nos. 4,315,874, 4,399,054 and 4,071,674.

[5] Tetrahydrofuran, that is a cyclic ether, has been variously utilized with a magnesium chloride compound, for example in US patent No. 4,482,687, as an additive for a cocatalyst, for example in US patent No. 4,158,642, as a solvent, for example in US patent No. 4,477,639 and the like.

[6] US patent Nos. 4,347,158, 4,422,957, 4,425,257, 4,618,661 and 4,680,381 suggest methods for preparing a catalyst, in which a Lewis acid compound such as aluminum chloride is added to a supporter, magnesium chloride, and the mixture is ground to prepare a catalyst. Disclosure of Invention Technical Problem

[7] Although the catalyst activity has been improved in above - mentioned patents, there still have been needs for further improvement regarding the catalyst morphology such as the shape, size, size distribution and stereoregularity of a catalyst.

[8] As it has been described above, the aspects for improving the commercial value of a catalyst for polymerization of alpha-olefin are focused on: efforts to produce a catalyst having a high polymerization activity and stereoregularity so as to enhance the product quality; efforts to control the shape and the size of a catalyst so as to improve productivity; and efforts to improve the production yield and the activity of a catalyst in catalyst preparation so as to save the production cost. These efforts are strongly needed in the art, since they are important factors in catalyst economy. Technical Solution

[9] The present invention has been designed to overcome the problems of prior arts. Accordingly, the object of the present invention is to provide a method for polymerization and copolymerization of olefin, which can provide high polymerization activity and a polymer of high stereoregularity. Mode for Invention

[10] The present invention can be further understood by the following examples, which are provided to illustrate the present invention, however by no means limiting the scope to be protected in the present invention.

[11] Examples

[12] Example 1

[13] Preparation of a prepolymerized catalyst (A)

[14] Step 1 : Preparation of a magnesium compound solution

[15] To a 500 L reactor equipped with a mechanical stirrer of which atmosphere was substituted with nitrogen, 15kg of MgCl , 225kg of toluene, 17kg of tetrahydrofuran and 31 kg of butanol were added. The mixture was heated to 110 °C with stirring at 70 rpm, and maintained at the temperature for 3 hours to obtain a homogeneous solution.

[16] Step 2 : Preparation of a carrier

[17] The solution obtained from the above step 1 was cooled to 17 °C and 32kg of TiCl was added thereto. The temperature of the reactor was elevated to 60 °C over 1 hour. When the temperature reached to 60 °C , 13kg of TiCl 4 was added to the reactor over

40 minutes and allowed it for reaction for further 30 minutes. After the reaction, it was allowed to stand for 30 minutes to settle the resulted carriers, and the upper part of the solution was removed. To the residual slurry in the reactor, 90kg of toluene was added, and the mixture was washed by repeating the series of steps of stirring, standing and removal of the supernatant, three times.

[18] Step 3: Preparation of a solid complex titanium catalyst

[19] To the carrier prepared from the above step 2, 80kg of toluene and 90 kg of TiCl 4 were added with stirring at the speed of 60 rpm. The reactor temperature was elevated to 110 °C over 1 hour, and the mixture was aged for 1 hour and allowed to stand for 15 minutes so as to settle precipitates, and the resulted supernatant was separated. To the remained slurry, 87 kg of toluene, 52 kg of TiCl 4 and 4.2 kg of diisobutylphthalate were added, and the temperature was elevated to 120 °C and maintained 1 hour for further reaction. After the reaction, it was allowed to stand for 30 minutes, and the supernatant was removed. To the reactor, 80 kg of toluene and 76 kg of TiCl 4 were added, and the mixture was reacted at 100 °C for 30 minutes. After the reaction, it was allowed to stand for 30 minutes, and the supernatant was removed. To the residual slurry, 65 kg of hexane was added, and the temperature of the reactor was raised to 60 °C and maintained for 30 minutes while stirring. After halting the stirring, the mixture was allowed to stand for 30 minutes and the supernatant was removed. The residual catalyst slurry was washed by adding hexane thereto, and this washing process was repeated 6 times, thereby obtaining the final solid complex titanium catalyst. The Ti content of the resulted catalyst was 2.8wt%.

[20] Step 4: Prepolymerization

[21] A 0.5 L high pressure reactor was cleansed with propylene and maintained at 15 °C .

To the reactor, 4g of the catalyst obtained from above step 3, 300 D of hexane, 10 mmol of triethylaluminum and 0.5 mmol of cyclohexylmethyldimethoxysilane were added in this order, and the mixture was stirred for 30 minutes. Prepolymerization was carried out at 15 °C for 3 hours, while flowing propylene at the rate of 80 ml/minute. In the prepolymerized catalyst resulted therefrom, the amount of polymers having high molecular weight formed around the catalyst was 6.8g per g of catalyst.

[22] Polymerization

[23] Polymerization of propylene was carried out in order to estimate the performance of the resulted prepolymerized catalyst. The prepared prepolymerized catalyst was placed in a high pressure bombe, with the amount of 10 mg, based on the solid complex titanium catalyst. The bombe was mounted to a 2L high pressure polymerization reactor, and the reactor was purged with nitrogen for about 1 hour so as to form dry nitrogen atmosphere inside the reactor. Thereto, triethylaluminum (Al/Ti molar ratio = 450) and dicyclohexyldimethoxysilane (Si/Al molar ratio =0.1) as an external donor were added, and the reactor was tightly closed. After feeding 1000 ml of hydrogen, 1200 ml of liquid propylene was fed through a syringe pump, and the temperature of the reactor was raised to 70 °C over 20 minutes. The prepolymerized catalyst was added to the reactor to carry out polymerization for 1 hour. After 1 hour, unreacted propylene was vented out to the air, and the temperature of the reactor was lowered to room temperature. The resulted polymer was dried in a vacuum oven at 50 °C and then weighed. With the resulted polymer, assays regarding xylene solubles and II (NMR pentad) were conducted, and the results were shown in Table 1. The xylene soluble assay is one of the methods for determining the isotactic index of polymers, wherein a certain amount of polymer sample is added to a xylene solution and completely dissolved thereinto at high temperature not less than 110 °C , and the resulted solution is cooled to room temperature and filtered. The precipitated materials collected by filtering is separated and measured for the content of xylene solubles.

[24] Example 2

[25] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 0.7 mmol of cyclohexyl- methyldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[26] Example 3

[27] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 0.9 mmol of cyclohexyl- methyldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[28] Example 4

[29] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 0.5 mmol of dicy- clopentyldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[30] Example 5

[31] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 0.5 mmol of diisopropy- ldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[32] Comparative example 1

[33] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that the electron donor, cyclo- hexylmethyldimethoxysilane was not used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[34] Comparative example 2

[35] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 3.5 mmol of an electron donor, cyclohexylmethyldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[36] Comparative example 3 [37] Preparation of a prepolymerized catalyst and polymerization were carried out as same as the method disclosed in Example 1, except that 7.0 mmol of an electron donor, cyclohexylmethyldimethoxysilane was used for preparing the prepolymerized catalyst, in the step 4 of the prepolymerized catalyst preparation method. The results were shown in Table 1.

[38] [Table 1] [Table ] Table 1

[39] As it can be seen from the above table 1, the examples according to the polymerization and copolymerization of olefin of the present invention exhibit the reduced amount of xylene solubles in the prepared polymers and improved stereoregularity and polymerization activity, as compared to the comparative examples. Industrial Applicability

[40] The method for polymerization and copolymerization of olefin according to the present invention provides high stereoregularity in the resulted polymers, and improved polymerization activity, thereby improving productivity of the polymerization process.

Claims

[1] L A method for polymerization or copolymerization of olefin which polymerizes or copolymerizes olefins in the presence of (A), (B) and (C):

(A) a prepolymerized catalyst obtained by prepolymerizing olefins in the presence of (a) a solid complex titanium catalyst prepared by the following steps, (b) an aluminum alkyl and (c) an electron donor, wherein the steps comprise:

(i) preparing a magnesium compound solution by dissolving a magnesium halide compound into an oxygen - containing solvent mixture of a cyclic ether and one or more alcohols;

(ii) preparing a carrier by firstly reacting the resulted magnesium compound solution with a titanium halide compound at -10 -30°C elevating the temperature or aging the resulted product to obtain particles, and secondly reacting the resulted product with a titanium halide compound;

(iii) preparing a titanium catalyst by reacting the obtained carrier with a titanium halide compound and an electron donor; and

(iv) washing the resulted catalyst with a hydrocarbon solvent at 40 -200 °C ;

(B) an organometallic compound from Group II or in of Periodic table of elements; and

(C) an external electron donor.

[2] 2. The method for polymerization or copolymerization of olefin according to claim 1, wherein the temperature for prepolymerization is -50 - 50 °C .

[3] 3. The method for polymerization or copolymerization of olefin according to claim 1, wherein the olefin is at least one selected from the group consisting of ethylene, propylene, 1 - butene, 1 - hexene and 1 - octene.

[4] 4. The method for polymerization or copolymerization of olefin according to claim 1, wherein the concentration of (a) the solid complex titanium catalyst in IL of solvent used in the prepolymerization system is 0.01 - 500 mmol, being calculated as titanium atom.

[5] 5. The method for polymerization or copolymerization of olefin according to claim 1, wherein (b) the aluminum alkyl is selected from trialkylaluminum and trialkenylaluminum.

[6] 6. The method for polymerization or copolymerization of olefin according to claim 1, wherein the amount of (b) the aluminum alkyl being used is 1 - 100 mole per mole of titanium atom in (a) the solid complex titanium catalyst.

[7] 7. The method for polymerization or copolymerization of olefin according to claim 1, wherein (c) the electron donor is an alkoxysilane compound.

[8] 8. The method for polymerization or copolymerization of olefin according to claim 7, wherein the alkoxysilane compound is selected from the group consisting of diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane, phenyl- methyldimethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, di- isopropyldimethoxysilane, di - t - butyldimethoxysilane, t - butyltrimethoxysilane, cyclohexylmethyldimethoxysilane, dicy- clopentyldimethoxysilane, dicyclohexyldimethoxysilane, 2 - norbornanetri- ethoxysilane, 2 - norbornanemethyldimetoxysilane and vinyltriethoxysilane. [9] 9. The method for polymerization or copolymerization of olefin according to claim 1, wherein the amount of (c) the electron donor being used is 0.001 - 3 moles per mole of titanium atom in (a) the solid complex titanium catalyst.