CA1116795A - Process for preparing low density ethylene copolymers - Google Patents
Process for preparing low density ethylene copolymersInfo
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- CA1116795A CA1116795A CA000342821A CA342821A CA1116795A CA 1116795 A CA1116795 A CA 1116795A CA 000342821 A CA000342821 A CA 000342821A CA 342821 A CA342821 A CA 342821A CA 1116795 A CA1116795 A CA 1116795A
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Abstract
ABSTRACT OF THE DISCLOSURE
A process for producing an ethylene copolymer having a density of from 0.900 to 0.945 g/cm3 by copolymerizing in two steps a predominant amount of ethylene with a minor amount of an alpha-olefin containing at least 3 car-bon atoms at room temperature to not more than about 100°C under a pressure of about 1 to about 100 kg/cm2 in the presence of a catalyst composed of (A) a titanium catalyst component supported on a magnesium compound and (B) an organoaluminum compound; characterized in that said copolymerization is car-ried out in (i) a first step where about 0.01 to abut 50 g, per gram of the titanium catalyst component (A), of the alpha-olefin containing at least 3 carbon atoms is polymerized, said catalyst further comprising an organic acid ester (C), and then (ii) a second step where the final product of ethyleue copolymer is formed in an amount more than about 100 times the weight of the polymer formed in the first step.
A process for producing an ethylene copolymer having a density of from 0.900 to 0.945 g/cm3 by copolymerizing in two steps a predominant amount of ethylene with a minor amount of an alpha-olefin containing at least 3 car-bon atoms at room temperature to not more than about 100°C under a pressure of about 1 to about 100 kg/cm2 in the presence of a catalyst composed of (A) a titanium catalyst component supported on a magnesium compound and (B) an organoaluminum compound; characterized in that said copolymerization is car-ried out in (i) a first step where about 0.01 to abut 50 g, per gram of the titanium catalyst component (A), of the alpha-olefin containing at least 3 carbon atoms is polymerized, said catalyst further comprising an organic acid ester (C), and then (ii) a second step where the final product of ethyleue copolymer is formed in an amount more than about 100 times the weight of the polymer formed in the first step.
Description
This invention relates to a process for produc-ing with commercial advantage by an easy operation an ethylene copolymer composed of a predominant amount of ethylene and a minor amount of an alpha-olefin containing at least 3 carbon a-toms which has a high bulk density and a low density and is free from fish eyesO
More specifically, this invention relates to a process for producing an ethylene copolymer having a density of from 00900 to 0O9L~5 g/cm3 by copolymerizing ln two steps a predominant amount of ethylene with a minor ~mount of an alpha-olefin containing at least ~
carbon atoms at room temperature to not more than about 100C under a pressure of about 1 to about 100 ~g/cm2 in the presence of a catalys-t com~osed of (A) a titanium catalyst component supported on a magnesium compound and ~B) an organoaluminum compound; characterized in that said copolymerization is carried out in (i) a first step where about OOO1 to about 50 g, per gram of the titanium catalyst component (A), of the alpha-olefin containing at leas-t 3 carbon atoms is polymerized, said catalyst further comprising an organic acid ester (C), and then ~ ii) a second step where the final product of ethylene copolymer is formed in an amount more than about 100 times the weight of the polymer formed in the first stepO
~ ~7 ~l~
.[t is known -that copolymerization of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms in the presence of a ~iegler catalyst affords ethylene copolymers having much the same density as hi~h-pressure polyethyleneO Generally, it is advantageous -to use high-temperature melt polymeri2ati~
which is carried out at a temperature above the melting point of the copolymer formed using a hydrocarbon sol~rent, because the polymerization operation of such a method is generally easy~ When it is desired to obtain a copolymer having a sufficiently high molecular weight, however, the concentration of the polymer in the solution must be reduced because -the viscosity of the polymer solution increasesO Accordingly, this causes the defect that the output of the copolymer per unit polymerization vessel is inevitably lowO
On the other hand, when the low-density ethylene copolymer is to be obtained by the slurr~ polymerization which is frequently used in the production o~` high.-density polyethylene, the copolymer is liable to be dissolved in, or swollen with, the polymcrization solven-t, and the concentration of the slurry cannot be increased because o~ the increase in the viscosity o~ the polymer solution, the adhosion of the polymer to th~? wall o~ the p~.~lymeriza-tion vessel, and the reduction o~ the bulk density of thepolymer, and moreover, the operat:ion cannot be performed continuously for a long period of time~ Moreover~ the quality of the resulting polymer is unsatisfactory because it becomes sticky.
~o In an attempt to remove the aforesaid defects associated wi-th the production of a low-density ethylene copolymer composed of a predominant amount of ethylene with a minor amount of an alpha-olefin con-taining at least 3 carbon atoms, some methods for the multi-step copolymer-ization of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms have been sugges-tedO
For example, Japanese ~aid-Open Patent Publica-tion No~ 52~l8~76 (llid-open on Mriy 10, 1976) discloses a p m c~s- fcr producing a low-density ethylene copolymer having a high bulk density9 which comprises a first step wherein in the presence of a liquid diluent and a catalyst composed of (1) a titanium catalyst component supported on fl magnesium compound obtained by copulverizing ~A
titanium compound selected from titanium tetrachloride, titanium trichloride and titanium trichloride composi-tions7 a magnesium halide and an aluminum halide/ether complex~ and (2) an organoaluminum compound catalyst component, ethylene is polymerized in an amount of flt least 5 g per gram of the titanium catalyst component, the amount of ethylene polymerized being up to 2~/o of the amount o~ the final product of ethylene copolymer formed, and subsequently a second step wherein a predominant amount of ethylene is copolymerized with a minor amount of an alpha-olefin containing at least 3 carbon atoms at a temperature of not over lOO~C using a low boiling hydrocarbon having a boiling point; of not more -than 40C
20 as a diluentO In this process, it; is essential to polymer-ize a small amount o~ ethylene in the first step~ '~he Publication does not at all refer to the use of an organic acid ester. Moreover, in this proeess, the boiling point of the liquid diluent usod in the second step is greatly limitedO
Japanese ~ai~-pen Patent Publication ~oO 121689/
77 (laid--open on October 13, 1977~ discloses a process for producing a low-density polyethylene containing a minor amount of an alpha-olefin containing at least 3 carbon atoms having a density of not more than 00945 ~cm3, whieh comprises a first step wherein in the presence of a catalyst composed of a titanium catalyst component sup-ported on a magnesium and~or aluminum compound consisting o~ a magnesium and/or aluminum compound and titanium tetrachloride and an organoaluminum compound, ethylene is polymeri~ed in an amount of 1 to 50 g per gram of the titanium catalyst component, a second step wherein ethylene is copolymerized with an alpha-olefin containing at least 3 carbon a-to~ls so that the proportion of the alpha-olefin is 10 to 80% of the final product of ethylene copolymer formed while in the initial stage it is adjusted to not more than 3% by weight based on the ethylene, and a third step wherein the reaction is completed while the propor-tion of the alpha-olefin copolymerized is increased to more than that in the second stage and up to 20~/o by weight based on ethylene, charac-terized in that the copolymerization is carried out in slurry in a hydrocarbon solvent having a boiling point of not more than 40~ at a temperature of not more than 100Co In this process, too, the polymerization of a small amount of ethylene in the first step is essential, and the Publication does not at all describe the use of an organic acid esterO
Furthermore, the process of this Publication requires three steps, and therefore, is complicated and disadvan-tageous in opera-tionO Moreover, the boiling point of the liquid diluent used in the copolymerization is greatly res-tricted.
Japanese ~aid-Open Patent Eublication NoO 124089/
77 (laid open on October 1~, 1977~ discloses a process, similar to those of the two .Public~tion~ cited above, for the production of an ethylene copolymer having a density of from 00925 to 00950 ~ c~3 composed of a predominant amoun-t of ethylene and a minor amount of an alpha-olefin containing at least 3 carbon atoms, which comprises a first step wherein in the presence of a catalyst composed of a titanium or vanadium catalyst component supported on a magnesium compound and an organoaluminum compound catalyst component, ethylene is polymerized in an amount of at least 50 g per gram of the titanium or vanadium catalyst component~ the amount of ethylene polymerized being adjusted to not more than 20% based on the final product of ethylene copolymer formed, and subsequently a second step wherein a predominant amount of ethylene is copolymerized with a minor amount of an alpha olefin contairling a-t least 3 carboIl atoms at a temperature of not more than 100C using a low boiling hydrocarbon having a boiling pOillt of no-t more than L~0OC as a diluentO In this process, too, it is essential, as in the process of the 5 Publication No~ 52487/769 to polymerize a small amount of ethylene in the first stepO ~he Phblication does not at all refer to the use of an organic acid esterO Moreover, the boiling point of the liquid diluent used in the second step is greatly limitedO It has been found that because the amount of ethylene polymerized in the first s-tep is too large, a film prepared from the final product of ethylene copolymer formed has undesirable fish eyesO
~ he present inventors made investigations in order to provide an improved process for the production of a low-density ethylene copolymer, which can rcmedy the defects associated with these prior techniquesO These~l investi~ations have led to the discove.ry tha-t the afore-said defects can be remedied by the aforesaid proce~ss comprising a combination of the specified first and second steps (i) flnd (ii); that relatively high boiling hydro-carbon solvents such as hexane or heptane conventionally used in the polymerization or copolymerization of olefins can be u~e(l in this process; and that by an easy operation, a high-quality low-dellsity ethylene copolymer having a high bulk density and being free from fish eyes can be produced in good yields with commercial advantageO
It is an object of this invention therefore to provide an improved two~s-tep process for the production of a low-density ethylene copolymer9 which can achieve the aforesaid advantagesa ~ he above and other objects and advantages of this invention will become more apparent from the follow-ing descriptionO
According to the process of this invention, the copolymerization of a predominant amount of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms is carried out b~r a two-step process 9~
involving the ~s-teps (i) and (ii) described hereinaboveO
~ he catalyst used in -the process is composed of (A) a -ti-tanium catalyst component supported on a magnesium compound and (B) an organoaluminum compound9 a~d also comprises (C) an organic acid esterO ~he organic acid ester may be supported in the component (A), or form a complex with part of the component (B)o ~he components (A) and (B) may be separately fed into the polymerization vessel at -the time of polymerization instead of mixing them p.rior to introduction into the polymerization vesseln Numerous methods have been known to produce the component (A)o Generally7 there are used a method which comprises reac-ting a titanium compound directly with a magnesium compound such as a magnesium halide, an alkoxy-magnesium, an aryloxymagnesium, an alkoxymagnesium halide,magnesium oxide. magnesium hydroxide, hydrotalci-te or Grignarcl compounds, an~ fl method which comprises reacting the aforesaid magnesium compound with an elec-tron donor, an organoalumi.num compound, a sill.con compound, etcO' and reacting the resultin~;~procluc-t with the titanium compoundO
Such methods can also be used in this inventionO The reaction of the magnesium compnund with the titanium com-pound to support the latter ~Il the former can b~ performed by known means, for example by a copulverization method, or by suspending a solid magnesium compound in a li~uid titanium compound.
~ he -titanium catalyst component (A) preferably contains abcut 003 to about 12% by weight, particularly about 006 to about 10% by weight, of titanium 2nd has a halogen/titanium atomic ratio of from about 4 -to about 200, particularly from about 6 to about 100 and a magnesium~titanium atomic ratio of from about 2 to about 100, particularly from about 3 to about 500 Pre~erably, the component (A) has a specific surface area vf at least about 20 m2/g, especially about 50 to about 800 m2/gO
In the present invention, the catalyst comprises an organic acid ester ~C)0 As stated aboveg component (C) s may he includecl:in the -titanium catalyst componen-t (A)~
In this case, the mo].e ratio of organic acid ester/titanium is pref`erably from about 0.1 -to abou-t 7, especially from about 002 to about 60 One example of ~the production of the component (A) containing the organic acid ester is described in German Laid-Open Patent Publication (D~-OS) NoO 2~73996080 Preferably, the -titanium catalyst component (A) has an average particle diameter in the range of about 5 to about 200 micronsO The geometric standard deviation ~g of its partiele size distribution is not more than~
about 205, preferably not more than about 201~ r~he pre-ferred shape of the titanium catalyst component (A) is a sphere, ellipse, flake, e-teO Suitable methods for the produetion of a titanium eatalyst eomponent of these pro-perties are deseribed, for example, in DT-OS 2~346~71 Drr -OS 2 ~ 345 ~ 7070 Dr~ ~OS 2, 641 ~ 960 ~ DT-OS 2 ~ 839 ~ 188 and DT-OS 2~735~6720 Or it can be ob-tained by treating a magnesium alkoxyhalide obtain~d by the reaetion of a 20 Grignard eompound and a silieie aeid ester, with a halogenating agent and/or an organic aeid ester, and reaeting the produet with the titanium eompoundO
~ xamples of the titaniu:m eompound used in the preparation of the titanium eatalys-t eom~one~nt (~) inelude titanium halides sueh as titanium tetraehloride, titanium tetrabromide and titanium tetrai.odide and -titanium alkoxy-halides hatring a Cl -- C8 alkox~ group, for example, alkoxytitanium trihalides such as r~i(OCH3)C1~, r~i(OC ~ 5)C13, r~i(0 n--C~Hg)Cl~ r~i(OC6H13)C13~ ~i(C8H17S 3 r~i~OC2H5)Br3, and r~i(O iso--C4H9)Br~; alkoxy-titanium dihalides sueh as ~i(OCH3)2C12, Ti~OC2H5)2C12, r~i(O n C~X9)2C12~ and r~i(O~2Hs~2Br2; trialkoxytitanium monohalides sueh as r~i(OCH3)3Cl, ~i(OC2H5)3Cl, r~i(O n--C4H9)3Cl and r~i(OC2H5)~rO r~itaniu~ tetrahalides sueh as titanium tetraehloride are espeeially preferredO
An example of the organoaluminum eompound (B), another eonstituent element of the eatalyst used in the - ~3 -process of this inven-tion, ls an organoaluminum compound having at least one ~l-carbon bond in the moleculeO
~xamples of such an organoalumi~Um compound are ~iven belowO
(1) Organoaluminum compounds of the general formula RlAl(OR2)nH X
wherein Rl and R2, independently from each other9 represent a group selected from the class consis-ting of Cl-C15~ preferably Cl-C47 hydrocarbon groups, X represents a halogen atom, such as chloro, bromo or iodo, and m is a number in the range of O<m~3, n is a number in the range of O~n<3, p is a n~nber in the range of O~p<3, q is a number in the range of ~.q<3, and m+n+p~q=3.
More specifically, this invention relates to a process for producing an ethylene copolymer having a density of from 00900 to 0O9L~5 g/cm3 by copolymerizing ln two steps a predominant amount of ethylene with a minor ~mount of an alpha-olefin containing at least ~
carbon atoms at room temperature to not more than about 100C under a pressure of about 1 to about 100 ~g/cm2 in the presence of a catalys-t com~osed of (A) a titanium catalyst component supported on a magnesium compound and ~B) an organoaluminum compound; characterized in that said copolymerization is carried out in (i) a first step where about OOO1 to about 50 g, per gram of the titanium catalyst component (A), of the alpha-olefin containing at leas-t 3 carbon atoms is polymerized, said catalyst further comprising an organic acid ester (C), and then ~ ii) a second step where the final product of ethylene copolymer is formed in an amount more than about 100 times the weight of the polymer formed in the first stepO
~ ~7 ~l~
.[t is known -that copolymerization of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms in the presence of a ~iegler catalyst affords ethylene copolymers having much the same density as hi~h-pressure polyethyleneO Generally, it is advantageous -to use high-temperature melt polymeri2ati~
which is carried out at a temperature above the melting point of the copolymer formed using a hydrocarbon sol~rent, because the polymerization operation of such a method is generally easy~ When it is desired to obtain a copolymer having a sufficiently high molecular weight, however, the concentration of the polymer in the solution must be reduced because -the viscosity of the polymer solution increasesO Accordingly, this causes the defect that the output of the copolymer per unit polymerization vessel is inevitably lowO
On the other hand, when the low-density ethylene copolymer is to be obtained by the slurr~ polymerization which is frequently used in the production o~` high.-density polyethylene, the copolymer is liable to be dissolved in, or swollen with, the polymcrization solven-t, and the concentration of the slurry cannot be increased because o~ the increase in the viscosity o~ the polymer solution, the adhosion of the polymer to th~? wall o~ the p~.~lymeriza-tion vessel, and the reduction o~ the bulk density of thepolymer, and moreover, the operat:ion cannot be performed continuously for a long period of time~ Moreover~ the quality of the resulting polymer is unsatisfactory because it becomes sticky.
~o In an attempt to remove the aforesaid defects associated wi-th the production of a low-density ethylene copolymer composed of a predominant amount of ethylene with a minor amount of an alpha-olefin con-taining at least 3 carbon atoms, some methods for the multi-step copolymer-ization of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms have been sugges-tedO
For example, Japanese ~aid-Open Patent Publica-tion No~ 52~l8~76 (llid-open on Mriy 10, 1976) discloses a p m c~s- fcr producing a low-density ethylene copolymer having a high bulk density9 which comprises a first step wherein in the presence of a liquid diluent and a catalyst composed of (1) a titanium catalyst component supported on fl magnesium compound obtained by copulverizing ~A
titanium compound selected from titanium tetrachloride, titanium trichloride and titanium trichloride composi-tions7 a magnesium halide and an aluminum halide/ether complex~ and (2) an organoaluminum compound catalyst component, ethylene is polymerized in an amount of flt least 5 g per gram of the titanium catalyst component, the amount of ethylene polymerized being up to 2~/o of the amount o~ the final product of ethylene copolymer formed, and subsequently a second step wherein a predominant amount of ethylene is copolymerized with a minor amount of an alpha-olefin containing at least 3 carbon atoms at a temperature of not over lOO~C using a low boiling hydrocarbon having a boiling point; of not more -than 40C
20 as a diluentO In this process, it; is essential to polymer-ize a small amount o~ ethylene in the first step~ '~he Publication does not at all refer to the use of an organic acid ester. Moreover, in this proeess, the boiling point of the liquid diluent usod in the second step is greatly limitedO
Japanese ~ai~-pen Patent Publication ~oO 121689/
77 (laid--open on October 13, 1977~ discloses a process for producing a low-density polyethylene containing a minor amount of an alpha-olefin containing at least 3 carbon atoms having a density of not more than 00945 ~cm3, whieh comprises a first step wherein in the presence of a catalyst composed of a titanium catalyst component sup-ported on a magnesium and~or aluminum compound consisting o~ a magnesium and/or aluminum compound and titanium tetrachloride and an organoaluminum compound, ethylene is polymeri~ed in an amount of 1 to 50 g per gram of the titanium catalyst component, a second step wherein ethylene is copolymerized with an alpha-olefin containing at least 3 carbon a-to~ls so that the proportion of the alpha-olefin is 10 to 80% of the final product of ethylene copolymer formed while in the initial stage it is adjusted to not more than 3% by weight based on the ethylene, and a third step wherein the reaction is completed while the propor-tion of the alpha-olefin copolymerized is increased to more than that in the second stage and up to 20~/o by weight based on ethylene, charac-terized in that the copolymerization is carried out in slurry in a hydrocarbon solvent having a boiling point of not more than 40~ at a temperature of not more than 100Co In this process, too, the polymerization of a small amount of ethylene in the first step is essential, and the Publication does not at all describe the use of an organic acid esterO
Furthermore, the process of this Publication requires three steps, and therefore, is complicated and disadvan-tageous in opera-tionO Moreover, the boiling point of the liquid diluent used in the copolymerization is greatly res-tricted.
Japanese ~aid-Open Patent Eublication NoO 124089/
77 (laid open on October 1~, 1977~ discloses a process, similar to those of the two .Public~tion~ cited above, for the production of an ethylene copolymer having a density of from 00925 to 00950 ~ c~3 composed of a predominant amoun-t of ethylene and a minor amount of an alpha-olefin containing at least 3 carbon atoms, which comprises a first step wherein in the presence of a catalyst composed of a titanium or vanadium catalyst component supported on a magnesium compound and an organoaluminum compound catalyst component, ethylene is polymerized in an amount of at least 50 g per gram of the titanium or vanadium catalyst component~ the amount of ethylene polymerized being adjusted to not more than 20% based on the final product of ethylene copolymer formed, and subsequently a second step wherein a predominant amount of ethylene is copolymerized with a minor amount of an alpha olefin contairling a-t least 3 carboIl atoms at a temperature of not more than 100C using a low boiling hydrocarbon having a boiling pOillt of no-t more than L~0OC as a diluentO In this process, too, it is essential, as in the process of the 5 Publication No~ 52487/769 to polymerize a small amount of ethylene in the first stepO ~he Phblication does not at all refer to the use of an organic acid esterO Moreover, the boiling point of the liquid diluent used in the second step is greatly limitedO It has been found that because the amount of ethylene polymerized in the first s-tep is too large, a film prepared from the final product of ethylene copolymer formed has undesirable fish eyesO
~ he present inventors made investigations in order to provide an improved process for the production of a low-density ethylene copolymer, which can rcmedy the defects associated with these prior techniquesO These~l investi~ations have led to the discove.ry tha-t the afore-said defects can be remedied by the aforesaid proce~ss comprising a combination of the specified first and second steps (i) flnd (ii); that relatively high boiling hydro-carbon solvents such as hexane or heptane conventionally used in the polymerization or copolymerization of olefins can be u~e(l in this process; and that by an easy operation, a high-quality low-dellsity ethylene copolymer having a high bulk density and being free from fish eyes can be produced in good yields with commercial advantageO
It is an object of this invention therefore to provide an improved two~s-tep process for the production of a low-density ethylene copolymer9 which can achieve the aforesaid advantagesa ~ he above and other objects and advantages of this invention will become more apparent from the follow-ing descriptionO
According to the process of this invention, the copolymerization of a predominant amount of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms is carried out b~r a two-step process 9~
involving the ~s-teps (i) and (ii) described hereinaboveO
~ he catalyst used in -the process is composed of (A) a -ti-tanium catalyst component supported on a magnesium compound and (B) an organoaluminum compound9 a~d also comprises (C) an organic acid esterO ~he organic acid ester may be supported in the component (A), or form a complex with part of the component (B)o ~he components (A) and (B) may be separately fed into the polymerization vessel at -the time of polymerization instead of mixing them p.rior to introduction into the polymerization vesseln Numerous methods have been known to produce the component (A)o Generally7 there are used a method which comprises reac-ting a titanium compound directly with a magnesium compound such as a magnesium halide, an alkoxy-magnesium, an aryloxymagnesium, an alkoxymagnesium halide,magnesium oxide. magnesium hydroxide, hydrotalci-te or Grignarcl compounds, an~ fl method which comprises reacting the aforesaid magnesium compound with an elec-tron donor, an organoalumi.num compound, a sill.con compound, etcO' and reacting the resultin~;~procluc-t with the titanium compoundO
Such methods can also be used in this inventionO The reaction of the magnesium compnund with the titanium com-pound to support the latter ~Il the former can b~ performed by known means, for example by a copulverization method, or by suspending a solid magnesium compound in a li~uid titanium compound.
~ he -titanium catalyst component (A) preferably contains abcut 003 to about 12% by weight, particularly about 006 to about 10% by weight, of titanium 2nd has a halogen/titanium atomic ratio of from about 4 -to about 200, particularly from about 6 to about 100 and a magnesium~titanium atomic ratio of from about 2 to about 100, particularly from about 3 to about 500 Pre~erably, the component (A) has a specific surface area vf at least about 20 m2/g, especially about 50 to about 800 m2/gO
In the present invention, the catalyst comprises an organic acid ester ~C)0 As stated aboveg component (C) s may he includecl:in the -titanium catalyst componen-t (A)~
In this case, the mo].e ratio of organic acid ester/titanium is pref`erably from about 0.1 -to abou-t 7, especially from about 002 to about 60 One example of ~the production of the component (A) containing the organic acid ester is described in German Laid-Open Patent Publication (D~-OS) NoO 2~73996080 Preferably, the -titanium catalyst component (A) has an average particle diameter in the range of about 5 to about 200 micronsO The geometric standard deviation ~g of its partiele size distribution is not more than~
about 205, preferably not more than about 201~ r~he pre-ferred shape of the titanium catalyst component (A) is a sphere, ellipse, flake, e-teO Suitable methods for the produetion of a titanium eatalyst eomponent of these pro-perties are deseribed, for example, in DT-OS 2~346~71 Drr -OS 2 ~ 345 ~ 7070 Dr~ ~OS 2, 641 ~ 960 ~ DT-OS 2 ~ 839 ~ 188 and DT-OS 2~735~6720 Or it can be ob-tained by treating a magnesium alkoxyhalide obtain~d by the reaetion of a 20 Grignard eompound and a silieie aeid ester, with a halogenating agent and/or an organic aeid ester, and reaeting the produet with the titanium eompoundO
~ xamples of the titaniu:m eompound used in the preparation of the titanium eatalys-t eom~one~nt (~) inelude titanium halides sueh as titanium tetraehloride, titanium tetrabromide and titanium tetrai.odide and -titanium alkoxy-halides hatring a Cl -- C8 alkox~ group, for example, alkoxytitanium trihalides such as r~i(OCH3)C1~, r~i(OC ~ 5)C13, r~i(0 n--C~Hg)Cl~ r~i(OC6H13)C13~ ~i(C8H17S 3 r~i~OC2H5)Br3, and r~i(O iso--C4H9)Br~; alkoxy-titanium dihalides sueh as ~i(OCH3)2C12, Ti~OC2H5)2C12, r~i(O n C~X9)2C12~ and r~i(O~2Hs~2Br2; trialkoxytitanium monohalides sueh as r~i(OCH3)3Cl, ~i(OC2H5)3Cl, r~i(O n--C4H9)3Cl and r~i(OC2H5)~rO r~itaniu~ tetrahalides sueh as titanium tetraehloride are espeeially preferredO
An example of the organoaluminum eompound (B), another eonstituent element of the eatalyst used in the - ~3 -process of this inven-tion, ls an organoaluminum compound having at least one ~l-carbon bond in the moleculeO
~xamples of such an organoalumi~Um compound are ~iven belowO
(1) Organoaluminum compounds of the general formula RlAl(OR2)nH X
wherein Rl and R2, independently from each other9 represent a group selected from the class consis-ting of Cl-C15~ preferably Cl-C47 hydrocarbon groups, X represents a halogen atom, such as chloro, bromo or iodo, and m is a number in the range of O<m~3, n is a number in the range of O~n<3, p is a n~nber in the range of O~p<3, q is a number in the range of ~.q<3, and m+n+p~q=3.
(2) Complex compounds containing Al and a metal of group I of the periodic table, expressed by the follow-ing general formula M AlR~
wherei.n Rl is as deflned i.n (1) above, and Ml represents Li, Na o.r K.
~xamples of the organoaluminum compound (1) are those of the general formula RmAl(OR2)3 m in which R and R are as defined above, and m is preferably a n~nbe.r in the range of 1~5~m~3; RmAlX3 m in which Rl is as defined above, X represents a halogen atom, and m is preferably O<m<3; RmAlH3 m ln whlch Rl ls as defined above, and m is preferably 2~m<3; and Rm Al(OR )nXq ln whlch R and R are as defined above, X represents a halogen atom~ O~m~3, O<n<3, O<q<3, m+n+q=30 Specific examples of the organoal~uninum com-pounds belonging to ~1) are triall~yl aluminums such as triethyl aluminum and tributyl aluminum; trialkenyl aluminums such as triisoprenyl aluminum, partially 9 .
alkoxykl-ted alkyl aluminums9 for example, dialkyl aluminum alkoxides such a.5 di.et~l aluminum e-thoxide and dibutyl aluminum butoxide; alkyl alur~num sesquialkoxides such as ethyl aluminum sesquiethoxide and butyl aluminum sesqui-butoxide~ compounds having an average composition expressedby R2 5Al(OR2)o 5; partially halogenated alkyl aluminums, for example, dialkyl aluminum halides such as diethyl aluminum chloride, dibutyl aluminum chloride and diethyl aluminum bromide; alkyl aluminum sesquihalides such as e-thyl aluminum sesquichloride, butyl aluminum sesquichlo-ride and ethyl aluminum sesquibromide; alkyl aluminum di.halides such as ethyl aluminum dichloride, propyl aluminurn dichloride and butyl aluminum dibromide; partially hydrogenated alkyl aluminums, for example, dialkyl aluminum hydrides such as diethyl aluminum hydride and dibutyl aluminum hydride, alkyl aluminum dihydrides such as ethyl aluminum dihydride and propyl aluminum dihydride; and partially alcoholated and halogenated alky]. aluminums, .for example, alkyl aluminum alkoxyhalides such as ethyl aluminunl ethoxychloride, butyl aluminum butoxychloride and ethyl aluminum ethoxybromideO
~ here can also be used organoaluminum compounds in whi.ch two or more aluminum atoms are bonded throu~h ~n oxy~en or ni.tro~en atom, as aluminum compounds similar 5 to those o~ formula (l)o Specific examples are (C2H5)2-2 5 2' ( 4 9)2AlOAl(C4H9)2 and (C2H5)2AlNAl(C2H ) Examples of the component (B) belonging to (2) above are LiAl(C2H5)4 and ~iAl(C ~ 15)~
Of these organoaluminum compounds (B), those belonging to (1) above are preferred, and trialkylaluminums and/or alkyl aluminum halides are especially preferredO
~ he catalyst u-tilized in the present invention further includes an organic acid ester (C)~ ~he organic acid ester includes, for example, C2-C20 aliphatic carboxy-lic acid esters, C6-C20 alicyclic carboxylic acid esters, 7~
1() -C7-C20 aro~1atic carboxylic acid esters9 C5-C10 lactones, and C3-C8 carbonic acid este:rsO
Sp~cific examples of the organic acid ester (C) include aliphatic carboxylic acid esters such as methyl ace-tate, butyl ace-tate, vinyl ace-tate, ethyl propionate, isopropy] butyrate, cyclohexyl acetate, phenyl acetate, benzyl aceta-te, methy] chloroacetate, methyl methacrylate, methyl laurate, and methyl stearate; alicyclic carboxylic acid esters such as methyl cyclohexanecarboxylate;
aromatic carboxylic acid esters such as methyl benzoate, ethyl benzoate, isopropyl benzoate, n-butyl benzoate, vinyl benzoate, cyclohexyl benzoate, phenyl benzoate, methyl toluate, ethyl toluate, methyl anisate, ethyl anisate~ dimethyl phthalate and methyl chlorobenzoate;
lactones such as gamma-butyrolactone, dilta-valerolactone, coumarine and phthalide; cmd carbonic acid esters such as ethy.le.ne carbonateO
According to the p:rocess of th:Ls invention, the first step (i) (or the pre-polymerization st~p) and the second step (ii) a:re carried out; in -the presence of the catalyst described above, preferclbly in an inert hydro-car~on solven-t~ In s-tep (i), a small amount o:E an alpha-olefin containing at least 3 ca:rbon a-toms is polymerizedO
In this step, ethylene in an amount of not more than 10 mole% of ethylene may be copolymerized with the alpha-olefinO The amount of polymerization in the pre~polymer-ization step (i) is about 0~01 to about 50 g, preferably about 0O05 to about 20 ~, per gram of the titani~un catalyst component (A)~ If this amount exceeds the upper limit described above fish eyes may occurO
Examples o~ -the inert hydrocarbon solvent pre-ferably used in the pre-polymerization include aliphatic hydrocarbons such as propane, butane~ n-pentane, iso-pentane, n-hexane~ n-octane, iso-octane, n-decane, n-dodecane and kerosene~ alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and methyl-cyclohexane~ arom~tic hydrocarbons such as benzene, -toluene and x~lene; and halogenated hydrocarbons such as methylene chloride, ethyl chloride, ethylene chloride and chlorobenzeneO Of these, aliphatic hydrocarbons~ espe-cially those having 4 to 10 carbon atoms, are preferredO
In the pre-polymerization step (i), it is preferred to use about OoOOl to about 500 millimoles7 especially 0O005 to about 200 millimoles, calculated as titanium atom of the titanium catalyst component (A) per li-ter of the inert hydrocarbon solventO Preferably~ the organoaluminum compound (B) is used in such a proportion that the Al/Ti atomic ratio is from about Ool to about 1000, especially from about 0O5 to about 500O The organic acid ester (C) may be supported on the component (A), or may be used as an adduct with a part of the component (~)0 ~lso, it may be added in the free state to the polymeriza-tion systemO In any case, the amount of the organic acid ester -to be presen-t is from about Ool to about 200 moles, especially from about 002 to about 50 moles, per mole of titanium atomO
Suitable alpha-olefins containing at least 3 carbon atoms use~ in the pre-polymerizati.on step (i) are thos~ having not more than 1~ carbon atoms such as pro-pylene, 1-butene, l--hexene 7 L~-m et;hyl-l-pentene~, 3-methyl-l-pen-tene, l-heptene, l-octene, l-decene, l--dodecene7 l-tetradecene, and l-octadeceneO Those having 3 to 6 carbon atoms are especially preferredO These alpha--ole~ins may be homopolymerized, or copolymersed with each other so long as a crystalline polymer results, or may also be copolymeri~.ed with not more than 10 mole% of ethylene as mentioned aboveO
The polymerization temperature in the first step (i) may be selected according to the -type of the alpha-olefin or the hydrocarbon solvent~ and may, for example, be about -40C to about 80Co ~or example, when the alpha-olefin is propylene~ the suitable polymerization -temper-ature is about -40C to about 70Co In the case of butene-l, it is abou-t -~0C to about ~0C 3 and in the case -- l2 o:E /-~--m~-l;hy].-l-pentene, o:r 3-methyl-1 pentene7 it is about -40C tc~ about 70~C~O The prepolym_~rization in step (i) may be carried out in the copresence of hydrogenO
According to the process of this invention, ethylene and an alpha-olefin con-taining at least 3 carbon atoms are copolymerized in the presence of the catalyst used in prepolymerizing the alpha-olefin having at least
wherei.n Rl is as deflned i.n (1) above, and Ml represents Li, Na o.r K.
~xamples of the organoaluminum compound (1) are those of the general formula RmAl(OR2)3 m in which R and R are as defined above, and m is preferably a n~nbe.r in the range of 1~5~m~3; RmAlX3 m in which Rl is as defined above, X represents a halogen atom, and m is preferably O<m<3; RmAlH3 m ln whlch Rl ls as defined above, and m is preferably 2~m<3; and Rm Al(OR )nXq ln whlch R and R are as defined above, X represents a halogen atom~ O~m~3, O<n<3, O<q<3, m+n+q=30 Specific examples of the organoal~uninum com-pounds belonging to ~1) are triall~yl aluminums such as triethyl aluminum and tributyl aluminum; trialkenyl aluminums such as triisoprenyl aluminum, partially 9 .
alkoxykl-ted alkyl aluminums9 for example, dialkyl aluminum alkoxides such a.5 di.et~l aluminum e-thoxide and dibutyl aluminum butoxide; alkyl alur~num sesquialkoxides such as ethyl aluminum sesquiethoxide and butyl aluminum sesqui-butoxide~ compounds having an average composition expressedby R2 5Al(OR2)o 5; partially halogenated alkyl aluminums, for example, dialkyl aluminum halides such as diethyl aluminum chloride, dibutyl aluminum chloride and diethyl aluminum bromide; alkyl aluminum sesquihalides such as e-thyl aluminum sesquichloride, butyl aluminum sesquichlo-ride and ethyl aluminum sesquibromide; alkyl aluminum di.halides such as ethyl aluminum dichloride, propyl aluminurn dichloride and butyl aluminum dibromide; partially hydrogenated alkyl aluminums, for example, dialkyl aluminum hydrides such as diethyl aluminum hydride and dibutyl aluminum hydride, alkyl aluminum dihydrides such as ethyl aluminum dihydride and propyl aluminum dihydride; and partially alcoholated and halogenated alky]. aluminums, .for example, alkyl aluminum alkoxyhalides such as ethyl aluminunl ethoxychloride, butyl aluminum butoxychloride and ethyl aluminum ethoxybromideO
~ here can also be used organoaluminum compounds in whi.ch two or more aluminum atoms are bonded throu~h ~n oxy~en or ni.tro~en atom, as aluminum compounds similar 5 to those o~ formula (l)o Specific examples are (C2H5)2-2 5 2' ( 4 9)2AlOAl(C4H9)2 and (C2H5)2AlNAl(C2H ) Examples of the component (B) belonging to (2) above are LiAl(C2H5)4 and ~iAl(C ~ 15)~
Of these organoaluminum compounds (B), those belonging to (1) above are preferred, and trialkylaluminums and/or alkyl aluminum halides are especially preferredO
~ he catalyst u-tilized in the present invention further includes an organic acid ester (C)~ ~he organic acid ester includes, for example, C2-C20 aliphatic carboxy-lic acid esters, C6-C20 alicyclic carboxylic acid esters, 7~
1() -C7-C20 aro~1atic carboxylic acid esters9 C5-C10 lactones, and C3-C8 carbonic acid este:rsO
Sp~cific examples of the organic acid ester (C) include aliphatic carboxylic acid esters such as methyl ace-tate, butyl ace-tate, vinyl ace-tate, ethyl propionate, isopropy] butyrate, cyclohexyl acetate, phenyl acetate, benzyl aceta-te, methy] chloroacetate, methyl methacrylate, methyl laurate, and methyl stearate; alicyclic carboxylic acid esters such as methyl cyclohexanecarboxylate;
aromatic carboxylic acid esters such as methyl benzoate, ethyl benzoate, isopropyl benzoate, n-butyl benzoate, vinyl benzoate, cyclohexyl benzoate, phenyl benzoate, methyl toluate, ethyl toluate, methyl anisate, ethyl anisate~ dimethyl phthalate and methyl chlorobenzoate;
lactones such as gamma-butyrolactone, dilta-valerolactone, coumarine and phthalide; cmd carbonic acid esters such as ethy.le.ne carbonateO
According to the p:rocess of th:Ls invention, the first step (i) (or the pre-polymerization st~p) and the second step (ii) a:re carried out; in -the presence of the catalyst described above, preferclbly in an inert hydro-car~on solven-t~ In s-tep (i), a small amount o:E an alpha-olefin containing at least 3 ca:rbon a-toms is polymerizedO
In this step, ethylene in an amount of not more than 10 mole% of ethylene may be copolymerized with the alpha-olefinO The amount of polymerization in the pre~polymer-ization step (i) is about 0~01 to about 50 g, preferably about 0O05 to about 20 ~, per gram of the titani~un catalyst component (A)~ If this amount exceeds the upper limit described above fish eyes may occurO
Examples o~ -the inert hydrocarbon solvent pre-ferably used in the pre-polymerization include aliphatic hydrocarbons such as propane, butane~ n-pentane, iso-pentane, n-hexane~ n-octane, iso-octane, n-decane, n-dodecane and kerosene~ alicyclic hydrocarbons such ascyclopentane, methylcyclopentane, cyclohexane and methyl-cyclohexane~ arom~tic hydrocarbons such as benzene, -toluene and x~lene; and halogenated hydrocarbons such as methylene chloride, ethyl chloride, ethylene chloride and chlorobenzeneO Of these, aliphatic hydrocarbons~ espe-cially those having 4 to 10 carbon atoms, are preferredO
In the pre-polymerization step (i), it is preferred to use about OoOOl to about 500 millimoles7 especially 0O005 to about 200 millimoles, calculated as titanium atom of the titanium catalyst component (A) per li-ter of the inert hydrocarbon solventO Preferably~ the organoaluminum compound (B) is used in such a proportion that the Al/Ti atomic ratio is from about Ool to about 1000, especially from about 0O5 to about 500O The organic acid ester (C) may be supported on the component (A), or may be used as an adduct with a part of the component (~)0 ~lso, it may be added in the free state to the polymeriza-tion systemO In any case, the amount of the organic acid ester -to be presen-t is from about Ool to about 200 moles, especially from about 002 to about 50 moles, per mole of titanium atomO
Suitable alpha-olefins containing at least 3 carbon atoms use~ in the pre-polymerizati.on step (i) are thos~ having not more than 1~ carbon atoms such as pro-pylene, 1-butene, l--hexene 7 L~-m et;hyl-l-pentene~, 3-methyl-l-pen-tene, l-heptene, l-octene, l-decene, l--dodecene7 l-tetradecene, and l-octadeceneO Those having 3 to 6 carbon atoms are especially preferredO These alpha--ole~ins may be homopolymerized, or copolymersed with each other so long as a crystalline polymer results, or may also be copolymeri~.ed with not more than 10 mole% of ethylene as mentioned aboveO
The polymerization temperature in the first step (i) may be selected according to the -type of the alpha-olefin or the hydrocarbon solvent~ and may, for example, be about -40C to about 80Co ~or example, when the alpha-olefin is propylene~ the suitable polymerization -temper-ature is about -40C to about 70Co In the case of butene-l, it is abou-t -~0C to about ~0C 3 and in the case -- l2 o:E /-~--m~-l;hy].-l-pentene, o:r 3-methyl-1 pentene7 it is about -40C tc~ about 70~C~O The prepolym_~rization in step (i) may be carried out in the copresence of hydrogenO
According to the process of this invention, ethylene and an alpha-olefin con-taining at least 3 carbon atoms are copolymerized in the presence of the catalyst used in prepolymerizing the alpha-olefin having at least
3 carbon atoms, thereby to produce an ethylene copolymer having a density of 0O900 to 0.9~5 g/cm3~
Suitable alpha-olefins having at least 3 carbon atoms used in the second s-tep (ii~ include thcse having no-t more than 18 carbon atoms such as propylene, 1-butene, 1 pentene, l-hexene, 4-me-thyl--1-penteIle, 1-heptene, l-octene, l-decene, l-dodecene, l-tetradecene, and l-octadeceneO
The copolymerization step (ii) is carried out at a temperature of not more than 100C, preferably from about 30 to about 85C, under such conditions that the r~sulting copolymer i~ not meltedO ~he copolym~rization in step (ii) is carried out so tha-t the amount of the final copolymer obtained is at leas-t about 100, prefer-ably at least 500, more preferabl;y at least 1000, times the amoun-t of the pol~mer formed in the first step (i)~
~he copolym~rization i.n step (~.i) may b~ carrled out in slurry, o:r ln -the gaseous phase in the absenc~ of a liquid hydrocarbonO r~he present invention exhibits a marked e~fect effect when it is applied to slurry polymerizationO As the hydrocarbon medium, inert hydrocarbons of the types exem-plified above wlth regard to step (i) or alpha~olefins are usedO Aliphatic hydrocarbons7 especially those having 3 to 12 carbon atOms7 are preferredO The great advantage of this invention is that gcod results can be obtained even when a solvent having a boiling point higher than 40C is usedO
~he concentration of -the catalyst in the slurry polymerization is preferably such that the amount of the titanium catalys-t component (A) is about 0.001 to about 1 milliTnole, preferably about 00003 -to about Ool millimole, calculated as titanium atOm, pex liter of the liquid phase, and the amount of the organoaluminum compound (B) is such -tha-t the Al/titanium atomic ratio is from about 2 to abou-t 2000, preferably from about 10 to ab~u-t 1000 To achieve a densi-ty within the aforesaid range~
the amount of -the alpha-olefin in the copolymer is limited, for example, to about 002 to about 30% by weight, espe-cially about 0O 3 to about 25% by weight~ although it differs depending upon the type of the catalys-t or the type of the alpha-olefinO ~or -this purpose, -the rate of feed of ~the alpha-olefi.n is properly selected depending upon the polymerization conditions such as the polymeriza--tion temperature and pressureO The polymerization pres-sure is generally from about 1 to about 1000 k ~cm2O ~ocontrol the nolecular weight of the copolymer, a molecular weight controlling agent such as hydrogen may be Eed into the pol~meriz~tion systemO Various electron donors, and silicon~ boron or tin compounds may be added to the catalys-t system in order to increase the catalyst activity or regulate the molecular weight distribu-tion of the copolymerO
The copolymerization of` thi.s invention may be carried out in two or more stages in whi.ch di:E:Eeren-t conditions are employedO
The followlng examples specifically illustrate the present inven-tion.
Example 1 Synthesis of catalyst:-ln a stream of nitrogen, 1 mole of commercially available metallicmagnesium was added to 500 ml of dehydrated and purified hexane, and 1.1 moles of tetraethoxysilane was further added. With stirring, the mixture was heated to 65C. Then, small amounts of methyl iodide and iodine were added dropwise, and 1.2 moles of n-butyl chloride was added dropwise over the course of 2 hours. The mixture was stirred at 70 C for 7 hours. After the reaction, the reaction mixture was repeatedly washed with hexane. Sub-sequently, 0.25 mole of ethyl benzoate was added and they were reacted at 60 C for l hour. The supernatant portion was withdrawn, and 10 moles of titanium tetrachloride was added to the remaining solid portion, and they were reacted at 120C Eor 2 hours. The titanium tetrachloride was with-drawn, and then under the same conditions as above, eitanium tetrachloride was reacted to support Ti. ~fter the reaction, the solid portion was re-peatedly washed with hexane. The resulting solid was analyzed for composi-Lon. ~t was Eound that the solid contained 29 mg of Ti, 205 mg of Mg, 650 mg of Cl, and 87 mg of ethyl benzoate per gram thereof.
The Ti catalyst component had an average particle diameter of 18.6 microns, a geometric standard deviation ~g of particle size distribution of 1.51, and a specific surface area of 230 m2/g.
Polymerization: -The titanium catalyst component obtained above was diluted withdehydrated and purified hexane so that the concentration of the catalyst component was 30 millimoles/liter calculated as titanium atom, and 3 milli-moles of triethylaluminum and 1 millimole of methyl toluate were added per L~79S
mlllimole oE tltanillm atom. Propylene was then fed at 30 C under atmos-pheric pressure, and reacted in an amount oE 1.62 g per gram of the solid catalyst, thus pre-treating the catalyst with propylene.
Separately, one liter of dehydrated and purified hexane was put into a 2-liter autoclave. The inside of the autoclave was purged sufficient-ly with nitrogen. The 1.5 millimoles of triethyl aluminum and 0.01 milli-ole, calculated as titanium, of the catalyst pretreated wi~h propylene were added. Then, hydrogen under a pressure of 1 kg/cm2 was fed, ar.d ethylene containing 7.5 mole% of l-butene was continuously added so that the total pressure inside the reactor reached 5 kg/cm2. Ethylene and l-butene were thus polymerized at 65C for 2 hours to afford 322 g of an ethylene copolymer having a bulk density of 0.46 g/cm and a melt index of 1.7 and a density of 0.928 g/cm3. The proportion oE the dissolved polymer based on the hexane solvent was 2.9~ by weight.
Examples 2 to 14 Various runs were conducted using the catalyst prepared by the method of Example L in the same way as in Example 1 except that the condi-ions for pre-treating with the alpha-olefin were changed, the polymerizat:Lon solvent used in the polymerization of ethylene and the alpha-olefin was changed,or the type of the alpha-olefin was changed, as shown in Tables 1-1 and 1-2. The results obtained are also shown in Table 1-2.
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Suitable alpha-olefins having at least 3 carbon atoms used in the second s-tep (ii~ include thcse having no-t more than 18 carbon atoms such as propylene, 1-butene, 1 pentene, l-hexene, 4-me-thyl--1-penteIle, 1-heptene, l-octene, l-decene, l-dodecene, l-tetradecene, and l-octadeceneO
The copolymerization step (ii) is carried out at a temperature of not more than 100C, preferably from about 30 to about 85C, under such conditions that the r~sulting copolymer i~ not meltedO ~he copolym~rization in step (ii) is carried out so tha-t the amount of the final copolymer obtained is at leas-t about 100, prefer-ably at least 500, more preferabl;y at least 1000, times the amoun-t of the pol~mer formed in the first step (i)~
~he copolym~rization i.n step (~.i) may b~ carrled out in slurry, o:r ln -the gaseous phase in the absenc~ of a liquid hydrocarbonO r~he present invention exhibits a marked e~fect effect when it is applied to slurry polymerizationO As the hydrocarbon medium, inert hydrocarbons of the types exem-plified above wlth regard to step (i) or alpha~olefins are usedO Aliphatic hydrocarbons7 especially those having 3 to 12 carbon atOms7 are preferredO The great advantage of this invention is that gcod results can be obtained even when a solvent having a boiling point higher than 40C is usedO
~he concentration of -the catalyst in the slurry polymerization is preferably such that the amount of the titanium catalys-t component (A) is about 0.001 to about 1 milliTnole, preferably about 00003 -to about Ool millimole, calculated as titanium atOm, pex liter of the liquid phase, and the amount of the organoaluminum compound (B) is such -tha-t the Al/titanium atomic ratio is from about 2 to abou-t 2000, preferably from about 10 to ab~u-t 1000 To achieve a densi-ty within the aforesaid range~
the amount of -the alpha-olefin in the copolymer is limited, for example, to about 002 to about 30% by weight, espe-cially about 0O 3 to about 25% by weight~ although it differs depending upon the type of the catalys-t or the type of the alpha-olefinO ~or -this purpose, -the rate of feed of ~the alpha-olefi.n is properly selected depending upon the polymerization conditions such as the polymeriza--tion temperature and pressureO The polymerization pres-sure is generally from about 1 to about 1000 k ~cm2O ~ocontrol the nolecular weight of the copolymer, a molecular weight controlling agent such as hydrogen may be Eed into the pol~meriz~tion systemO Various electron donors, and silicon~ boron or tin compounds may be added to the catalys-t system in order to increase the catalyst activity or regulate the molecular weight distribu-tion of the copolymerO
The copolymerization of` thi.s invention may be carried out in two or more stages in whi.ch di:E:Eeren-t conditions are employedO
The followlng examples specifically illustrate the present inven-tion.
Example 1 Synthesis of catalyst:-ln a stream of nitrogen, 1 mole of commercially available metallicmagnesium was added to 500 ml of dehydrated and purified hexane, and 1.1 moles of tetraethoxysilane was further added. With stirring, the mixture was heated to 65C. Then, small amounts of methyl iodide and iodine were added dropwise, and 1.2 moles of n-butyl chloride was added dropwise over the course of 2 hours. The mixture was stirred at 70 C for 7 hours. After the reaction, the reaction mixture was repeatedly washed with hexane. Sub-sequently, 0.25 mole of ethyl benzoate was added and they were reacted at 60 C for l hour. The supernatant portion was withdrawn, and 10 moles of titanium tetrachloride was added to the remaining solid portion, and they were reacted at 120C Eor 2 hours. The titanium tetrachloride was with-drawn, and then under the same conditions as above, eitanium tetrachloride was reacted to support Ti. ~fter the reaction, the solid portion was re-peatedly washed with hexane. The resulting solid was analyzed for composi-Lon. ~t was Eound that the solid contained 29 mg of Ti, 205 mg of Mg, 650 mg of Cl, and 87 mg of ethyl benzoate per gram thereof.
The Ti catalyst component had an average particle diameter of 18.6 microns, a geometric standard deviation ~g of particle size distribution of 1.51, and a specific surface area of 230 m2/g.
Polymerization: -The titanium catalyst component obtained above was diluted withdehydrated and purified hexane so that the concentration of the catalyst component was 30 millimoles/liter calculated as titanium atom, and 3 milli-moles of triethylaluminum and 1 millimole of methyl toluate were added per L~79S
mlllimole oE tltanillm atom. Propylene was then fed at 30 C under atmos-pheric pressure, and reacted in an amount oE 1.62 g per gram of the solid catalyst, thus pre-treating the catalyst with propylene.
Separately, one liter of dehydrated and purified hexane was put into a 2-liter autoclave. The inside of the autoclave was purged sufficient-ly with nitrogen. The 1.5 millimoles of triethyl aluminum and 0.01 milli-ole, calculated as titanium, of the catalyst pretreated wi~h propylene were added. Then, hydrogen under a pressure of 1 kg/cm2 was fed, ar.d ethylene containing 7.5 mole% of l-butene was continuously added so that the total pressure inside the reactor reached 5 kg/cm2. Ethylene and l-butene were thus polymerized at 65C for 2 hours to afford 322 g of an ethylene copolymer having a bulk density of 0.46 g/cm and a melt index of 1.7 and a density of 0.928 g/cm3. The proportion oE the dissolved polymer based on the hexane solvent was 2.9~ by weight.
Examples 2 to 14 Various runs were conducted using the catalyst prepared by the method of Example L in the same way as in Example 1 except that the condi-ions for pre-treating with the alpha-olefin were changed, the polymerizat:Lon solvent used in the polymerization of ethylene and the alpha-olefin was changed,or the type of the alpha-olefin was changed, as shown in Tables 1-1 and 1-2. The results obtained are also shown in Table 1-2.
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~ lcs 15 to 19 __ Synthesis of catalyst:-Catalys-ts were synthesized in the same way as in Ex~mple 1 except that various esters were used instead of the ethyl benzoate~ and were pre-treated with propylene in the same way as in Example 1. Then, under thesame polymerization conditions as in Example 1, ethylene and l-butene were copolymerized. The results obtained are shown in Table 2.
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E~ple 20 ___ Synthesis of a catalyst:-In a stream of nitrogen, 2 moles of commercially available anhyd-ous magnesium chloride was suspended in 4 liter~ of dehydrated and purified hexane, and with stirring, 12 moles of ethanol was added dropwise over the course of 2 hours. The reaction was performed at 70 C for 1 hour. Then, 5.85 moles of diethyl aluminum chloride was addeddropwise at room temper-ature, and stirred for 2 hours. Subsequently, 3 moles of titanium tetra-chloride was added dropwise, and the reaction was per~ormed at room temper-ture for 2 hours. After the reaction, the resulting solid port~on was re-peatedly washed with hexane. It was found that the resulting solid con-tained 63 mg of Ti, 590 mg of Cl, 185 mg of Mg and 155 mg o~ the OEt group per gram thereof. The solid catalyst had a specific surface area of 225 m /g oE solid, an average particle diameter of 16.6 microns and a geometric standard deviation of particle size distribution of 1.69.
Polymerization:-The titanium catalyst component obtained as above was diluted withdehydrated and purified hexane so that the concentration oE the catalyst component reached 30 millimoles/liter calculated as titanium atom. Then, 3 millimoles of triethyl aluminum and l millimole of methyl p-toluate were added per millimole of titanium atom. Subsequently, propylene was fed at 20C under atmospheric pressure, and 1.29 g of propylene was reacted per gram of the solid catalyst to pre-treat the catalyst.
Separately, one liter of dehydrated and purified hexane was pu~
into a 2-liter autoclave. The inside of the autoclave was sufficiently purged with nitrogen, and l.O millimole of triethyl aluminum and O.Ol milli-mole, calculated as titanium atom, of the above catalyst pretreated with propylene were added. Subsequently, hydrogen under l kg/cm was charged, æ
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alld ethylorle containing 6.3 mole % of 1-butene was continuously added so that the total pressure in the au~oclave reached 4 kg/cm2. Thus, ethylene and l-butene were copolymerized at 65C for 2 hours to afford 255 g of an ethylene copolymer having a bulk density of 0.39 g/cm3 and a melt index of 1.3 and a density of 0.932 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 3.0% by weight.
Example 21 Synthesis of a catalyst:-Two kilograms of commercially available magnesium hydroxide having a specific surface area was suspended in 11 liters of water, and the suspen-sion was stirred for 1 hour at a rotating speed of 5,000 rpm using a homo-mixer having a 20-liter turbine stator. Subsequently, the resulting aqueous slurry of magnesium hydroxide was heated to 80C with stirring, and sprayed with a concurrently flowing hot air at 200C using a spray drier having two fluid nozzles with a nozzle diameter of 0.254 mm, to obtain spherical par-ticles of magnesium hydroxide. Then, the product was screened to obtain particles having a size of 20 to 63 microns. The treated magnesium hydrox-icle was spherical and had a specific surface area of 86 m2/g.
Thirty grams of the resulting spherical magnesium hydroxicle was added to 400 ml of titanium tetrachloride and reacted for 2 hours at 135C.
After the reaction, titanium tetrachloride was wlthdrawn. The solid portion was repeatedly washed with hexane. The resulting solid was analyzed for composition. It was found that the solid contained 19 mg of Ti, 360 mg of Mg and 290 mg of Cl per gram thereof.
Thirty grams of the solid obtained as above was put into a three-necked flask fully purged with nitrogen, and 150 ml of kerosene was added.
Ethyl benzoate ~as added dropwise in an amount of 4 moles (47.6 millimoles) per mole of the supported Ti at a reaStion temperature of 30C, and the mix-s tu~e was stirred nt 3()C For I hollr. Then, die-thyl alumin-m~ chloride was added dropwise in an amo-lnt of l/2 mole per mole of ethyl ben~oate at 30C, and after the addition, the mixture was stirred at 30C for 1 hour. The kerosene solvent was then removed by decantation. The resulting solid was washed twice with 150 ml of kerosene, and 150 ml of titanium tetrachloride was added. They were reacted at 130C for 2 hours. The reaction mixture was repeatedly washed with hexane. The solid was analyzed for composition, was found to contain 20 mg of Ti, 310 mg of Cl, 330 mg of Mg and 38 mg of ethyl benzoate. The resulting catalyst had an average particle diameter of 37 microns, a geometric standard deviation of particle size distribution of 1.40, and a specific surface area of 90 m2/g.
Polymerization:-The titanium catalyst component obtained as above was diluted with dehydrated and puriEied hexane so tllat the concentration of the catalyst component reached 20 millimoles/liter. Then, 3 millimoles of triethyl alum-inum and 1 millimole of methyl p-toluate were added per millimole of titan-ium atom. Subsequently, propylene was fed at 10C under atmospheric pres-sure, and propylene was reacted in an amount ot 1.~0 g per gram of the solid catalyst. The catalyst was pre-treated wlth propylene.
Separately, the inside of a 2-liter autoclave was purged fully with nitrogen, and 2.0 millimoles of triethyl aluminum, and 0.02 millimole calculated as titanium atom of the pre-treated catalyst were added. Subse-quently, hydrogen under 1.5 kg/cm2 was charged, and ethylene containing 7.5 mole % of l-butene was added continuously so that the total pressure in the reactor reached 6 kg/cm2-G. Thus, ethylene and l-butene were copolymerized at 60C for 2 hours to afford 331 g of a copolymer having a bulk density of 0.40 g/cm and a melt index of 0.95 and a density of 0.929 g/cm3. The pro-portion of the polymer dissolved in the hexane solvent was 5.1% by weight.
_aml)le 22 Synthesis of a catalyst:-Commercially available anhydrous magnesium chloride ~20 g) and6.0 ml of ethyl benzoate were charged into a stainless steel vessel having a capacity of 800 ml and an inside diameter of 100 mm and containing 100 stainless steel (SUS-302) balls having a diameter of 15 mm in an atmosphere of nitrogen, and copulverized for 50 hours by a vibratory mill device hav-ing a power of 7 G. The solid treated product obtained was suspended in titanium tetrachloride, and reacted at 100C for 2 hours. The solid portion was separated by filtration, and repeatedly washed with hexane. The re-sulting solid catalyst component was analyzed for composition, and found to contain 21 mg of Ti, 210 mg of Mg, 670 mg of Cl and 88 mg of ethyl benzoate.
The titanium catalyst component had an average particle diameter of 17.8 microns, a geometric standard deviation of particle size distribution of 2.24, and a specific surface area of 185 m /g.
Polymerization:-The same pre-treatment as in Example 1 was performed to polymerize 1.7 g of propylene per gram of the catalyst. Subse~uently, ethylene and 1-butene were copolymerized in tlle same way as in Example 21 to afford 244 g of an ethylene copolymer having a bulk density of 0.35 g/cm3 and a melt index of 1.1. The ethylene copolymer had a density of 0.931 g/cm . The proportion of the dissolved polymer based on the hexane solvent was 3.9% by weight.
Comparative Example 1 Synthesis of a catalyst:-Commercially available anhydrous magnesium chloride ~20 g) wascharged into a stainless steel vessel having a capacity of 800 ml and a di-ameter of 100 mm and containing 100 stainless steel (SUS-302) balls each '7~5 having a cliclmeter of lS mm in an atmosphere of nitrogen, and pulverized for 50 hours by a vibratory mill device having a power of 7 G The resulting solid treated product was suspended in titanium tetrachloride, and reacted at 120C for 2 hours. The solid portion was separated by filtration, and waslled repeatedly with hexane. The resulting solid catalyst component was analyzed for composition, and it was found that the solid contained 10 mg of Ti, 235 mg of Mg, and 730 mg of Cl per gram thereof. The resulting titanium catalyst component had an average particle diameter of 12.2 mi-crons, a geometric standard deviation of particle size distribution of 2.31, and a specific surface area of 55 m2/g.
Polymerization:-In the same way as in Example 1, the catalyst was pre-treated with propylene in an amount of 1.~3 g per gram of the catalyst. At this time, an electron donor such as methyl p-tol~ate was absent in the reaction system.
Ethylene and l-butene were copolymerized uncler the same conditions as in Ex~
ample 1 using the pre-treated catalyst. There was obtained 115 g of an ethylelle copolymer having a bulk density of 0.22 g/cm3 and a melt index of 1.9. The resultillg copolymcr had a density o~ 0.9~1 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 10.6~ by weight.
Thus, the bulk density and the yield of the polymer were very poor.
Comparative Example 2 In the method of Example 1, titanium tetrachloride was reacted without reacting ethyl benzoate in the synthesis of the titanium catalyst component. After the reaction, the solid was analyzed for composition, and found to contain 59 mg of Ti, 210 mg of Mg and 690 mg of Cl per gram there-of.
The resulting titanium catalyst component was pre-treated with propylene in an amount of 1.58 g per gram of the solid catalyst. At this 7~5 timc, mcthyl p-toluate was not added.
Separately, ethylene and 1-butene were copolymerized under the same conditions as in Example 1 in a 2-liter autoclave using the resulting titanium catalyst component. There was obtained 267 g of an ethylene co-polymer having a bulk density of 0.31 g/cm3 and a melt index of 1.8. The resulting copolymer had a density of 0.936 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 7.3% by weight.
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~ lcs 15 to 19 __ Synthesis of catalyst:-Catalys-ts were synthesized in the same way as in Ex~mple 1 except that various esters were used instead of the ethyl benzoate~ and were pre-treated with propylene in the same way as in Example 1. Then, under thesame polymerization conditions as in Example 1, ethylene and l-butene were copolymerized. The results obtained are shown in Table 2.
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E~ple 20 ___ Synthesis of a catalyst:-In a stream of nitrogen, 2 moles of commercially available anhyd-ous magnesium chloride was suspended in 4 liter~ of dehydrated and purified hexane, and with stirring, 12 moles of ethanol was added dropwise over the course of 2 hours. The reaction was performed at 70 C for 1 hour. Then, 5.85 moles of diethyl aluminum chloride was addeddropwise at room temper-ature, and stirred for 2 hours. Subsequently, 3 moles of titanium tetra-chloride was added dropwise, and the reaction was per~ormed at room temper-ture for 2 hours. After the reaction, the resulting solid port~on was re-peatedly washed with hexane. It was found that the resulting solid con-tained 63 mg of Ti, 590 mg of Cl, 185 mg of Mg and 155 mg o~ the OEt group per gram thereof. The solid catalyst had a specific surface area of 225 m /g oE solid, an average particle diameter of 16.6 microns and a geometric standard deviation of particle size distribution of 1.69.
Polymerization:-The titanium catalyst component obtained as above was diluted withdehydrated and purified hexane so that the concentration oE the catalyst component reached 30 millimoles/liter calculated as titanium atom. Then, 3 millimoles of triethyl aluminum and l millimole of methyl p-toluate were added per millimole of titanium atom. Subsequently, propylene was fed at 20C under atmospheric pressure, and 1.29 g of propylene was reacted per gram of the solid catalyst to pre-treat the catalyst.
Separately, one liter of dehydrated and purified hexane was pu~
into a 2-liter autoclave. The inside of the autoclave was sufficiently purged with nitrogen, and l.O millimole of triethyl aluminum and O.Ol milli-mole, calculated as titanium atom, of the above catalyst pretreated with propylene were added. Subsequently, hydrogen under l kg/cm was charged, æ
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alld ethylorle containing 6.3 mole % of 1-butene was continuously added so that the total pressure in the au~oclave reached 4 kg/cm2. Thus, ethylene and l-butene were copolymerized at 65C for 2 hours to afford 255 g of an ethylene copolymer having a bulk density of 0.39 g/cm3 and a melt index of 1.3 and a density of 0.932 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 3.0% by weight.
Example 21 Synthesis of a catalyst:-Two kilograms of commercially available magnesium hydroxide having a specific surface area was suspended in 11 liters of water, and the suspen-sion was stirred for 1 hour at a rotating speed of 5,000 rpm using a homo-mixer having a 20-liter turbine stator. Subsequently, the resulting aqueous slurry of magnesium hydroxide was heated to 80C with stirring, and sprayed with a concurrently flowing hot air at 200C using a spray drier having two fluid nozzles with a nozzle diameter of 0.254 mm, to obtain spherical par-ticles of magnesium hydroxide. Then, the product was screened to obtain particles having a size of 20 to 63 microns. The treated magnesium hydrox-icle was spherical and had a specific surface area of 86 m2/g.
Thirty grams of the resulting spherical magnesium hydroxicle was added to 400 ml of titanium tetrachloride and reacted for 2 hours at 135C.
After the reaction, titanium tetrachloride was wlthdrawn. The solid portion was repeatedly washed with hexane. The resulting solid was analyzed for composition. It was found that the solid contained 19 mg of Ti, 360 mg of Mg and 290 mg of Cl per gram thereof.
Thirty grams of the solid obtained as above was put into a three-necked flask fully purged with nitrogen, and 150 ml of kerosene was added.
Ethyl benzoate ~as added dropwise in an amount of 4 moles (47.6 millimoles) per mole of the supported Ti at a reaStion temperature of 30C, and the mix-s tu~e was stirred nt 3()C For I hollr. Then, die-thyl alumin-m~ chloride was added dropwise in an amo-lnt of l/2 mole per mole of ethyl ben~oate at 30C, and after the addition, the mixture was stirred at 30C for 1 hour. The kerosene solvent was then removed by decantation. The resulting solid was washed twice with 150 ml of kerosene, and 150 ml of titanium tetrachloride was added. They were reacted at 130C for 2 hours. The reaction mixture was repeatedly washed with hexane. The solid was analyzed for composition, was found to contain 20 mg of Ti, 310 mg of Cl, 330 mg of Mg and 38 mg of ethyl benzoate. The resulting catalyst had an average particle diameter of 37 microns, a geometric standard deviation of particle size distribution of 1.40, and a specific surface area of 90 m2/g.
Polymerization:-The titanium catalyst component obtained as above was diluted with dehydrated and puriEied hexane so tllat the concentration of the catalyst component reached 20 millimoles/liter. Then, 3 millimoles of triethyl alum-inum and 1 millimole of methyl p-toluate were added per millimole of titan-ium atom. Subsequently, propylene was fed at 10C under atmospheric pres-sure, and propylene was reacted in an amount ot 1.~0 g per gram of the solid catalyst. The catalyst was pre-treated wlth propylene.
Separately, the inside of a 2-liter autoclave was purged fully with nitrogen, and 2.0 millimoles of triethyl aluminum, and 0.02 millimole calculated as titanium atom of the pre-treated catalyst were added. Subse-quently, hydrogen under 1.5 kg/cm2 was charged, and ethylene containing 7.5 mole % of l-butene was added continuously so that the total pressure in the reactor reached 6 kg/cm2-G. Thus, ethylene and l-butene were copolymerized at 60C for 2 hours to afford 331 g of a copolymer having a bulk density of 0.40 g/cm and a melt index of 0.95 and a density of 0.929 g/cm3. The pro-portion of the polymer dissolved in the hexane solvent was 5.1% by weight.
_aml)le 22 Synthesis of a catalyst:-Commercially available anhydrous magnesium chloride ~20 g) and6.0 ml of ethyl benzoate were charged into a stainless steel vessel having a capacity of 800 ml and an inside diameter of 100 mm and containing 100 stainless steel (SUS-302) balls having a diameter of 15 mm in an atmosphere of nitrogen, and copulverized for 50 hours by a vibratory mill device hav-ing a power of 7 G. The solid treated product obtained was suspended in titanium tetrachloride, and reacted at 100C for 2 hours. The solid portion was separated by filtration, and repeatedly washed with hexane. The re-sulting solid catalyst component was analyzed for composition, and found to contain 21 mg of Ti, 210 mg of Mg, 670 mg of Cl and 88 mg of ethyl benzoate.
The titanium catalyst component had an average particle diameter of 17.8 microns, a geometric standard deviation of particle size distribution of 2.24, and a specific surface area of 185 m /g.
Polymerization:-The same pre-treatment as in Example 1 was performed to polymerize 1.7 g of propylene per gram of the catalyst. Subse~uently, ethylene and 1-butene were copolymerized in tlle same way as in Example 21 to afford 244 g of an ethylene copolymer having a bulk density of 0.35 g/cm3 and a melt index of 1.1. The ethylene copolymer had a density of 0.931 g/cm . The proportion of the dissolved polymer based on the hexane solvent was 3.9% by weight.
Comparative Example 1 Synthesis of a catalyst:-Commercially available anhydrous magnesium chloride ~20 g) wascharged into a stainless steel vessel having a capacity of 800 ml and a di-ameter of 100 mm and containing 100 stainless steel (SUS-302) balls each '7~5 having a cliclmeter of lS mm in an atmosphere of nitrogen, and pulverized for 50 hours by a vibratory mill device having a power of 7 G The resulting solid treated product was suspended in titanium tetrachloride, and reacted at 120C for 2 hours. The solid portion was separated by filtration, and waslled repeatedly with hexane. The resulting solid catalyst component was analyzed for composition, and it was found that the solid contained 10 mg of Ti, 235 mg of Mg, and 730 mg of Cl per gram thereof. The resulting titanium catalyst component had an average particle diameter of 12.2 mi-crons, a geometric standard deviation of particle size distribution of 2.31, and a specific surface area of 55 m2/g.
Polymerization:-In the same way as in Example 1, the catalyst was pre-treated with propylene in an amount of 1.~3 g per gram of the catalyst. At this time, an electron donor such as methyl p-tol~ate was absent in the reaction system.
Ethylene and l-butene were copolymerized uncler the same conditions as in Ex~
ample 1 using the pre-treated catalyst. There was obtained 115 g of an ethylelle copolymer having a bulk density of 0.22 g/cm3 and a melt index of 1.9. The resultillg copolymcr had a density o~ 0.9~1 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 10.6~ by weight.
Thus, the bulk density and the yield of the polymer were very poor.
Comparative Example 2 In the method of Example 1, titanium tetrachloride was reacted without reacting ethyl benzoate in the synthesis of the titanium catalyst component. After the reaction, the solid was analyzed for composition, and found to contain 59 mg of Ti, 210 mg of Mg and 690 mg of Cl per gram there-of.
The resulting titanium catalyst component was pre-treated with propylene in an amount of 1.58 g per gram of the solid catalyst. At this 7~5 timc, mcthyl p-toluate was not added.
Separately, ethylene and 1-butene were copolymerized under the same conditions as in Example 1 in a 2-liter autoclave using the resulting titanium catalyst component. There was obtained 267 g of an ethylene co-polymer having a bulk density of 0.31 g/cm3 and a melt index of 1.8. The resulting copolymer had a density of 0.936 g/cm3. The proportion of the dissolved polymer based on the hexane solvent was 7.3% by weight.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing an ethylene copolymer having a density of from 0.900 to 0.945 g/cm3 by copolymerizing in two steps a predominant amount of ethylene with a minor amount of an alpha-olefin containing at least 3 carbon atoms at room temperature to not more than about 100°C under a pressure of about 1 to about 100 kg/cm in the presence of a catalyst com-posed of (A) a titanium catalyst component supported on a magnesium compound and (B) an organoaluminum compound; characterized in that said copolymeriza-tion is carried out in (i) a first step where about 0.01 to about 50 g, per gram of the titanium catalyst component (A), of the alpha-olefin containing at least 3 carbon atoms is polymerized, said catalyst further comprising an organic acid ester (C), and then (ii) a second step where the final product of ethylene copoly-mer is formed in an amount more than about 100 times the weight of the poly-mer formed in the first step.
2. The process of claim 1 wherein in the titanium catalyst compon-ent (A), the atomic ratio of halogen to titanium is from about 4 to about 200, and the atomic ratio of magnesium to titanium is from about 2 to about 100.
3. The process of claim 1 wherein said organoaluminum compound (B) is selected from the group consisting of (1) compounds of the formula RmAl(OR2)mHpXq wherein R1 and R2, independently from each other, represent a C1-C15 hydrocarbon group, X represents a halogen atom, m is a number in the range of 0 < m < 3, n is a number in the range of 0 ? n < 3, p is a number in the range of 0 ? p < 3, q is a number in the range of 0 ? q < 3, and m + n + p + q = 3, and (2) complex compounds containing A1 and a metal of group I of the periodic table expressed by the following formula wherein R1 is the same as defined above, and Ml represents Li, Na or K.
4. The process of claim 1 wherein said organic acid ester (C) is selected from the group consisting of C2-C20 aliphatic carboxylic acid esters, C6-C20 alicyclic carboxylic acid esters, C7-C20 aromatic carboxylic acid esters, C5-C10 lactones and C3-C8 carbonic acid esters.
5. The process of claim 1 wherein said first step (i) is carried out in an inert hydrocarbon solvent using the titanium catalyst component (A) in an amount of about 0.005 to about 200 millimoles/liter of solvent calculated as Ti atom, the organoaluminum compound (B) in an amount such that the atomic ratio of Al to Ti is from about 0.1 to about 1000, and the organic acid ester (C) in an amount of about 0.1 to about 200 moles per mole of titanium atom.
6. The process of claim 1 wherein said second step (ii) is carried out using the titanium catalyst component (A) in an amount of about 0.001 to about 1 millimole calculated as titanium atom, the organoaluminum compound (B) in such an amount that the atomic ratio of Al to Ti is from about 2 to about 2000, and the organic acid ester (C) in an amount of about 0.1 to about 200 moles per mole of titanium atom, all per liter of the liquid phase of reaction system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000342821A CA1116795A (en) | 1979-12-31 | 1979-12-31 | Process for preparing low density ethylene copolymers |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000342821A CA1116795A (en) | 1979-12-31 | 1979-12-31 | Process for preparing low density ethylene copolymers |
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| CA1116795A true CA1116795A (en) | 1982-01-19 |
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| CA000342821A Expired CA1116795A (en) | 1979-12-31 | 1979-12-31 | Process for preparing low density ethylene copolymers |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5494871A (en) * | 1992-03-27 | 1996-02-27 | Elf Atochem S.A. | Process for preparing a prepolymerized olefin polymerization catalyst |
-
1979
- 1979-12-31 CA CA000342821A patent/CA1116795A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5494871A (en) * | 1992-03-27 | 1996-02-27 | Elf Atochem S.A. | Process for preparing a prepolymerized olefin polymerization catalyst |
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