CA1085996A - PROCESS FOR PREPARING .alpha.-OLEFIN POLYMERS OR COPOLYMERS - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The invention is a process for preparing .alpha.-olefin polymers or copolymers having improved stereoregularity and bulk density. The process involves polymerising or copolymerizing .alpha.-olefins in the presence of a catalyst comprising (A) a solid titanium complex catalyst component and (B) an organometallic compound of a metal of groups I to III of the Periodic Table. The polymerization or copolymerization is carried out in two steps:
(a) a first step where at least about 100 millimoles, per millimole of titanium atom, of an .alpha.-olefin is polymerized or copolymerized at a temperature less than about 50°C, to form a polymer of copolymer the amount of which is not more than about 30% by weight based on the final product obtained in the second step, and (b) a second step where the final product is formed at at temperature highter than the temperature of the first step and from about 50°C, to about 90°C.

Description

1~8s9g6 This invention relate~ to an improved proce for a-olefin polymers or copolymer~ having improved stereoregularity and bulk den~ity with improved cata-lytic activity by polymerizing or copolymerizing ~-olefin~ containing at lea~t 3 carbon atoms or copoly-merizing a-olefin~ containing at least 3 carbon atom~
with ethylene, in two ~tepg under ~pecified condition~
in the presence of a cataly#t comprising (A) a solid titanium complex cataly~t component (A) con~lsting es-sentlally of magne~ium, titanium, halogen and an electron donor, and (B) an organometallic compound of a metal of Group~ I to III of the periodic table.
It ha~ been known that a cataly~t comprising (A) a solid titanium complex, cataly~t component (A) con-~i~tlng esffentially o~ ma$nesium, titanium, halogen and an elec~ron donor And (B) fln organometallic co~pound of a metal of Groups I to III of the periodic table is useful for preparing a-olefin polymer~ or copolymers having good stereoregularity with superior catalytic activity, and a number of suggestions have been made about the use of ~olid ~ titanium complex catalyst components (A) prepared from : various combinations of catalygt-forming component~ and/or under specified combinations of cataly~t-forming combi-~- nations (for example, German Laid-Open Patent Publication No. 2230728 corresponding to Japane~e Laid-Open Patent Publication No. 16986t73 and French Patent 2143347; German Laid-Open Patent Publication No. 2347577 corresponding to Japanese Laid-Open Patent Publication No. 86482/74, Briti~h Pate-,lt 1,435,768 and French Patent 2,200,290;
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lq)~3S996 German Laid-Open Patent Publication ~o. 2504036 corre9 ponding to Japanege Laid-Open Patent Publication~ Nos.
108385/75 and 20297~76, and French Patent 2259842; German Laid-Open Patent Publication No. 2553104 corresponding to Japanese Laid-Open Patent Publication No. 126590/75;
~utch Patent No, 7510394 corresponding to Japanese Laid-Open Patent Publication No. 28189f76 and French Patent 2283909; Japanege Laid-Open Patent Publication No.
57789/76; Japanese Laid-Open Patent Publication No.
64586/76; German Laid-Open Patent Publication No. 2605922 corresponding to Japanese Laid-Open Patent Publication No. 92885/76; Japanese Laid-Open Patent Publication No.
127185/76; and Japanese Laid-Open Patent Publication No.
136625!76) .
However, there has been no pogitive suggestion about a two-step polymerization process using the cata-lyst component (A) because the two-step process i9 ap-parently disadvantageous over a one-step process in com-mercial operAtions and no benefit which would cancel such a di~advantage can be expected from the two-step process.
~ Some suggestions about the two-step polymeri-- zation of propylene with conventional titanium trichloride-type catalysts such as a titanium trichloride composition ; obtained by reducing titanium tetrachloride with metallic ~ 25 aluminum or other reducing agents have been known (for .~ example, Japanese Patent Publication No. 32312~72, :-! Japanese Patent Publication No. 14865.~74~ and British Patent 1359844 corresponding to Japanese Laid-Open Patent Publication No. 2439 '72) . It is well known however that ,; - 3 -in the polymerization of propylene utilizing these con-ventional titanium trichloride-type catalyst components which are different from the afore#aid catalyst com-ponent R, the use of high reaction temperatures in an attempt to increase polymerization activity reduces the crystallinity of the polymer, and convergely, the use of low reaction temperatures in an attempt to increase crystallinity inevitably regults in the reduced polymeri-zation activity of the catalyst~ Hence, in consideration of the baLance between polymerization activity and crystal-linity, temperatures of about 60 to about 70C. are em-ployed as most suitable for the polymerization of propylene.
It is noted that when propylene i9 polymerized with these conventional titanium trichloride-type catalyst components at about 60 to 70C., there is substantially no difference in result between a one-step polymerization process and a two-step polymerization procesg which in~ol~es a first-step polymerization performed at low temperatures and a second-step ~olymerization performed at about 60 to 70C.
. 20 Specifically, the amount of polymer formed per unit weight of catalyst per unit time is substantially the same for~ both processes, and in the case of a batchwise reaction,the proportion of a stereoregular polymer formed and the bulk density of the polymer are substantially the same for both, or is slightly higher in the two-step process. Accordingly, no substantial benefit of employ-ing the two-step process at the sacrifice of the operatin~
::s disadvantage is seen.
.- When the second step of the two-step polymerization :

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1~8S996 process u~ing the conventional titanium trichloride cata-lyst component is carried out at a temperature of more than about 80C., the amount yielded of the polymer, the bulk density of the polymer~ and the yield of a highly stereoregular polymer tends to decrease as shown, for example, by the experimental data in Japanese Patent Publication No. 14865~7L~ cited hereinaboveO The use of such higher temperatures iY not practical.
The present inventors made investigations in order to obtain improved results in the polymerization or copolymerization of a-olefins containing at least 3 carbon atoms, the copolymerization of a-olefins contain-ing at least 3 carbon atoms with ethylene, preferably with up to 10 mole/0 of ethylene, or the copolymerization of these a-olefins with dienes (these may sometimes be re-ferred to simply as the polymerization or copolymerization of a-olefins containing at least 3 carbon atoms) using a solid titanium complex catalyst component (A) consisting essentially of magnesium, titanium, halogen and an electron donor which is of a different type from the conventional titanium trichloride-type catalyst components. These in-vestigations led to the unexpected discovery that the use ; of a two-step polymerization process with the catalyst ; component (A) under specified conditions can achieve im-proved catalytic activity and stereoregularity and in-creased bulk density.
It has also been found that when the catalyst component (A) is used in the aforesaid two-step polymeri-zation method with the conventional titanium trichloride \/

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lV85996 catalyst in ~4hich the second step is performed at about Go to 70 C. within which temperature range no substantial benefit is seen of employing the operationally dis-advantageous two-step process as compared with the one-~tep process, a marked increase in catalytic activitywhich i8 quite unexpected from the first-gtep polymeri-zation can be obtained. These unexpected results cannot be anticipated froM the results achieved by the two-step polymerization process using the conventional titanium trichloride catalyst.
It has also been found that ~t poly~erization temperatures of at least 70Co ~ for example, more than 80C., at which the amount of crygtalline polypropylere tends to decrease, the reaction mixture can be prevented 15 from becoming viscoug ag a re~ult of an increase in the amount of an amorphous polymer and the subgtantial decrease ln the yield of the polymer can also be avoided~
; The excellent results achieved by the process of thi~ invention utilizing the catalyst component (A) cannot be expected from the results of the two-step polymerization , ., process with the conventional titanium trichloride cata-lysts.
. It is an object of this invention therefore to . j , .
provide a markedly improved process for polymerizing or copolymeri~.ing ~-olefins containing at least 3 carbon atoms in two steps.

; The above and many other objects and advantages of the invention will become apparent from the following , description.
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108~996 According to the present invention, there is provided a process for preparing a-olefin polymers or : copolymers by polymerizing or copolymerizing a-olefins containing at least 3 carbon atoms at room temperature or a higher temperature under a pressure of about l to 100 kg~cm2 in the presence of a catalyst comprising (A) a solid titanium co~plex catalyst component consisting essentially of magnesium, titanium, halogen and an electron donor, and (B) an organometallic compound of a metal of Groups I to III of the periodic table, such as an alkyl aluminum compound, wherein the polymerization or copoly-meri~ation is carried out in two step~:
(a) a first step where at least about 100 milli-moles per millimole of the titanium atom of an a-olefin is polymerized at a temperature of les~ than about 50C.
to form a polymer or copolymer the amount of which is not more than about 30/0 by weight of that of the final product obtained in the second step, and ; (b) a second step where the final product is formed at a temperature higher than the temperature of the first step and from about 50C. to about 90C.
. The solid complex titanium component (A) is .~ obtained by intimately contacting a magne~ium compound ~ (or magnesium metal), a titanium compound and an electron .. 25 donor by such means as heating or copulveri~.ation. The so~id complex has a halogen..~titanium molar ratio of more -: than about 4, and does not substantially pçrmit the libe-ration of a titanium compound when washed with hexane at room temperature . q`he chemic al structure of th:l s .~ .

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1~85996 solid complex is now known~ but presumably, the magneqium atom and the titanium atom are bonded firmly by, for example, having the halogen in commonO The solid com-plex may, depending upon the met~aod of preparatlon, con-tain another metal atom such ag aluminu~, silicon, tin,boron~ germanium, calcium and zinc, an electron donor, or an organic group ascribable thereto. It may further contain an organic or inorganic inert diluent, such as LiCl, CaC03, BaCl2, N~2C03, SrC12, B203~ 2 4 2 3 SiO2~ Ti2' NaB47~ Ca3(P04)2~ CaS04, hl2(S04)3, CaC12~
ZnC12, potyethylene, polypropylene, and polystyrene. Pre-ferably, the solid complex ig the one treated with an electron donor. In preferred examples of the solid com-plex titanium component (a), the halogen~titanium molar ratio exceeds about 4, preferably at least abou* 5, more preferably at least about 8, and the magnesium~titanium molar ratio is at lea~t about 3, preferably about 5 to about 50, and the electron donor~titanium molar ratio of about 0.2 to about 6, preferably about 0.4 to about 3, more preferably about o.8 to about 2. Furthermore, the specific surface area of the solid is at least 3 m2~g, preferably at leaqt about 40 m2,'g, and ~ore preferably at least about lO0 m2/g. It is also desirable that the X-ray spectrum of the solid complex (a) should show amorphous character irrespsctive of the starting magnesium compound, or it is in a more amorphous state than ordinary commercially available grades of magnesium dihalide.
The solid titanium complex catalyst component (A) can be prepared by means known ~ se. These means - , , ~ ~ . - . ' .

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1[)85~96 are disclosed, for example, in the prior patents cited hereinabove with regard to the utilization of solid titanium complex catalyst components (A), and also in Canadian Applications Serial Nos. 269,946, 272,787, 279,660, and 281,521 and Japanese Laid-Open Patent Applications 100596/77 and 151691/77 both published in 1977.
Typical methods disclosed in these documents : involve the reaction of at least a magnesium compound i 10 (or metallic magnesium), an electron donor and a titanium ; compound.
Examples of the electron donor are oxygen-con-taining electron donors such as water, alcohols, phenols, ketones, aldehydes, carboxylic acids, esters, ethers, and acid amides, and nitrogen-containing electron donors such as ammonia, amines, nitriles, and isocyanates.
Specific examples of such electron donors in-. clude alcohols containing 1 to 18 carbon atoms such as methanol, ethanol, propanol, pentanol, hexanol, octanol, dodecanol J octadecyl alcohol, benzyl alcohol, phenylethyl alcohol, cumyl alcohol, and isopropyl benzyl alcohol;
phenols containing 6 to 15 carbon atoms which may contain :~ a lower alkyl group such as phenol, cresol, xylenol, ethyl phenol, propyl phenol, cumyl phenol, and naphthol; ketones containing 3 to 15 carbon atoms such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone and benzo-.: phenone; aldehydes containing 2 to 15 carbon atoms such as acetaldehyde, propionaldehyde, octyl aldehyde, benz-aldehyde, tolualdehyde and naphthoaldehyde; organic acid esters containing 2 to 18 carbon atoms such as methyl formate, methyl acetate, ethyl acetate, vinyl acetate, _ g -.

propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valeratel methyl chloro-acetate, ethyl dichloroacetate, methyl rnethacrylate, ethyl crotonate, ethyl cyclohexanecarboxylate, methyl ben~oate, ethyl ben~oate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl ben~oate, benzyl benzoate, methyl toluate, ethy toluate, amyl toluate~
ethyl ethylbenzoate, methyl anisate, ethyl anisate, ethyl ethoxybenzoate, Y-butyrolactone, -valerolactone, coumarine, phthalide and ethylene carbonate; acid halides containing

2 to 15 carbon atoms such as acetyl chloride, benzyl chloride, toluic acid chloride, and anisic acid chloride;
ethers containing ~J to 20 carbon atoms such as methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran, anisole, and diphenyl ether; acid amides such as acetamide, benzamide and toluamide; amines such as methylamine, ethylamine, diethylamine, tributyl-amine, piperidine, tribenzylamine, aniline, pyridine, picoline and tetramethylethylene diamine; nitriles such as acetonitrile, ben~onitrile and tolunitrile; and com-pounds of aluminum, silicon, tin, etc. which contain the - aforesaid functional groups in the molecule. These electron donors can be used as a mixture of two or more~
Suitable magnesium compounds used for the form-ation of the solid coi~plex titanium compound (A) are those containing halogen andfor organic groups. Specific examples of such magnesium compounds include magnesium ~' dihalides, magnesium alkoxyhalides, magnesium aryloxyhalides, magnesium hydroxyhalides, magnesium dialkoxides, magnesium '' .

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~85996 diaryloxides, magnesium alkoxyaryloxides, magnesium acyloxyhalides, magnesium alkylhalides, magnesium aryl-halides, magnegium dialkyl compoun~s~ mag~esium diaryl compounds, and magnesium alkylalkoxides. They may be present in the form of adduct~ ~ith the aforesaid electron donors. Or they may be double compounds containing other metals such as aluminum, tin, silicon, germanium, ~inc or boron. For example, they may be double compounds of halides, alkyl compounds, alkoxyhalides, aryloxyhalides, a~koxides and aryloxides of metal~ such as aluminum, and the above-exemplified magnesium compounds. ~r they may be double compounds in which phosp'norus or boron is bonded to magnesium metal through oxygenO These magnesium com-pounds may be a mixture of two or more. Usually, the above-exemplified compounds can be expressed by simple chemicalformulae, hut sometimes, according to the method of prepa-ration of th~ magnesium compounds, they cannot be expressed by simple formulae. They are usually regarded as mixtures of the aforesaid compoundsO For ex.ample, compounds obtained by a method which comprises reacting magnesium metal with an alcohol or phenol in the presence of a halosilane, phos-phorus oxychloride, or thionyl chloride, and a method which comprises pyroly~ing Grignard reagents, or decomposing them with compounds having a hydroxyl group, a carbonyl group, an ester linkage, an ether linkage, or the like are considered to be mixtures of various compounds accord-ing to the amounts of the reagents or the degree of re-actionO Tnese compounds can of course be used in this inventionO

' lV85996 Various methods for producing the magresium compounds exernplified hereinabove are known, and products of any of these methods can be uged in this invention.
Also, prior to use, the magnesium compound may be treated, for example, by a method ~hich comprises dissolving it ; singly or together with another metal compound in ether or acetone, and then evaporating th~ solvent or putting the solution into an inert solvent thereby to separate the solid. A method can also be employed which involves pre-pulveri~ng mechanically at least one magnesium com-pound ~ith or without another metal compound.
Preferred among these magnesium compounds are magnesium dihalides, aryloxyhalides and aryloxides, and ; double compounds of these with aluminum, silicon, etcO
More specifically, they are MgC12, MgBr~, MgI2, MgF2, 6 ~ ' g( 6H5)2 MgCl(OC6H4-2-CH3), Mg(OC6H4-2-CH ) (MgCl2)x(Al(oR)ncl3-n)y~ and (MgC12) ~Si~OR)mC14 m)y. In these formulae, R is a hydrocarbon group such as an alkyl - or aryl group, and m or n R groups are the sams or different, and 0~ n_ 2, 0_ m~ 4, and x and y are positive numbers.
MgC12 and its complexes or double compounds are especially preferred.
Suitable titanium compounds u~ed for the formation of the solid com~lex titanium compound (~) are tetravalent ~ 25 titanium compounds of the formula Ti(OR)gX4 g wherein R
L~? is a hydrocarbon group, preferably an alkyl group contain-ing 1 to 6 carbon atoms, X is a halogen atom, and 0~ g~ 40 Examples of the titanium compounds are titanium tetra-halides such as TiC14, TiBr4 or TiI4; alkoxytitanium _ 12 -;, , : . :
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1~8S996 trihalides such as Ti(OCH3)C13, Ti(OC ~ 5)C13, Ti(O n-C4H9)C13, Ti(OC2H~)Br3, and l`i(O iso-C4H9)Br3; alkoxy-titanium dihalides such as Ti(OC~3)2C12, Ti(OC ~5)2C12, Ti(O n-C4H9)2C12, and Ti(OC2H5)~Br2; trialkoxytitanium 5 monohalides such as Ti(OCH3)3Cl, Ti(OC ~5)3Cl, Ti(O n-CI~Hg)3C] and Ti(OC2H5)3Br; and tetraalkoxytitanium such ~.g Ti(OCH3)4, Ti(OC2H5)~. and Ti(O n-c4Hg)4. Of the titanium tetrahalides are preferred, and especially preferred is titanium tetrachloride.
There are various examples of reacting the magnesium compound (or metallic magnesium), the electron donor and the titanium c~mpound, to prepare the titanium complex catalyst component (A), and typical ones are de-scribed belowO
(I) Method involving reacting the magnesium compound uith the electron donor and then reacting the reactio~ mixture with the titanium compound:-(I-a) ~ethod (I) with the copulverization of the magnesium compound and the electron donor:-The electron donor added at the time of copul-verization needs not to be in the free state, and may be present in the form of an adduct with the magnesium com-poundO ~.t the time of copulverization, additional in-: gredients, which may be ircluded in the complex titanium component (A), for exa~ple, the aforesaid organic or in-organic inert diluent, a halogenating agent such as a halogen compound of silicon, a silicon compound such as polysiloxane, and a compound of aluminu~, germanium or tin, or a part of the titanium compound may be present together.

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~V8S9g6 Or the electron donor may be pregent in the for~ of an adduct (complex compound~ with guch a co~pound. The amount of the e~ectron donor used is preferably about 0.005 to about 10 moles, more preferably about OoOl to about 1 mole, per mole of the magnesium compound.
The copulverization Irlay be carried out by using ordinary devices such as a rotary ball mill, a vibratory bal.l mill, and an impact mill. If the rotary ball mill is used, and 100 stainless steel (SUS 32) balls having a diameter of 15 mm are accomodated in a ball mill cylinder having an inner capacity of 800 ml and an inside diameter of 100 ~m and made of stainless steel (SUS 32) and 20 to 40 g of the materials to be treated are put into it, it i5 advisable to perform the pulverization for at least 24 hours, preferably at least 4~ hours at a rotating speed of 125 rpmO The temperature of the pulverization treatment is usually room temperature to about 100C.
The copulverized product can also be reacted with the titanium compound by copulverizing meansO How-. 20 ever, it is preferred to suspend the copulverized product .~ in at least about 0005 mole, preferably about 0.1 to about~ 50 moles, per mole of the magnesium compound, of a liquid ,., i titanium compound with or without an inert solvent in the absence of copulveri~ationO The reaction temperature is from room temperature to about 200C., and the reaction . time is from 5 minutes to about 5 nours. The reaction can of course be performed under conditions outside th~se specified rangesO After the reaction, the reaction mixture ; is hot-filtered at a h~gh temperature of, say, about 60 to ~, ~V8599~

150C. to isolate the product which i~ then well washed with an inert solvent before use in polymerization.
(I-b) Method (I) without the copulverization of the magnesium compound and the electron donor:-U~ually, the magnesium compound is reacted with the electron donor in an inert solvent, or the magnesium compound is dissolved or susperlded in the liquid electron donor for reaction. It is pos~ible to employ an embodi-ment in whica magneYium metal is used as a starting mate-rial, and reacted with the electron donor while forming a magnesium compound.
The amount of the electron donor used is pre-ferably about OoOl to æbout 10 moles, more preferably about 0005 to about 6 moles, per mole of the magnesium compoundO The reaction proceeds sufficiently at a reaction temperature of from room temperature to about 200C. for 5 minutes to about 5 hour~. After the reaction, the reaction mixture was filtered or evaporated, and washed with a-n inert solvent to isolate the productO The reaction of the re-action product with the titanium compound can be performed ~ in the same way as de3cribed in (I-a).
!. (I-c~ ~ethod which comprises reacting the r0-action procuct between the magnesium compound and the electron donor with a compound selected from organoaluminum compounds, silicon compounds and tin compounds, and then . ~ .
rea_t~ng the resulting product further with the titanium compound:-~ This method is a special embodiment of the method ; (I-b~o Generally, complexes obtained by the method (I-a) ''' - ~5 -:.
' ' : : ' , ' ; , ~V~S996 have superior properties, but some of complexes obtained by the method (I-b) ha~e inferior properties to those obtained by method (~-a)0 The properties of such com-plcxes can be ~ery effectively improved by the performance of method (I-c) in whic'n tle organoaluminum compound, silicon compound or tin compound is reacted prior to the reaction with the titanium compoundO
Examples of the organoaluminum compounds that can be used ~n this method are trialkyl alwninums, di-alkyl aluminum hydride~, dialkyl aluminum halides, alkyl aluminum sesquihalides, alkyl aluminum dihalides, dlalkyl aluminum alkoxides or phenoxides9 alkyl aluminum alkoxy halides or phenoxyllalides, and mixtures of these. Of these, the dialkyl aluminum halides~ alkyl aluminum susquihalides, alkyl alwminum dihalides~ and mixtures of these are pre-ferred. Specific e~amples of these include triethyl aluminum, triisobutyl aluminu~, diethyl aluminum hydride, dibutyl aluminum hydride, diethyl aluminum chloride, diisobutyl alumïnum bromide, ethyl aluminum ses~uichloride, diethyl aluminum ethoxide, ethyl aluminum ethoxy chloride, ethyl aluminum dichloride, and butyl aluminum dichloride.
The silicon or tin co~pounds,for example silicon or tin halogen compounds or organic compounds, are com-pounds containing at least one halogen or hydrocarbon :~ 25 group directly bonded to silicon or tin, and may furthercontaining hydrogen, an alkoxy group, a phenoxy group, or the like. Specific examples include, silicon tetra-halides, tetraalkyl silicons, silicon alkyl halides, silicon alkylhydrides, tin tetrahalides, tin alkylhalides, .
~. -1~5996 and tin hydride halides. Of these, silicon tetrachloride and tin tetrachloride are preferredO
The reaction of the resulting reacti~n product between the magnesium compound and the electron donor with the organoaluminum compound, ~ilicon compound or tin compound may be carried out in an inert solvent. Such a com~ound is used in an amount of preferably about 0.1 to about 20 moles, more preferably about 0.5 to about 10 moles, per mole of the magne3ium compoundO The reaction ls carried out preferably at a temperature of from room temperature-to about 100C. for 5 minutes to 5 hours.
After the reaction, the reaction mixture is preferably well washed with an inert solvent, and then reacted with the titanium compoundO The reaction of this reaction product with the titanium compourd can be performed in accordance l with the method described in (I-a).
(II) Method which comprise~ simultaneously reacting the magnesium compound, the electron donor and the titanium compound.
- 20 ~III) Method which comprises reacting the reaction product between the titanium compound and the electron donor with the magnesium compound.
~ The reactions in the methods (II~ and ~III) are - preferably performed by copulverization. The pulverization conditions and the proportions of the raw materials are the same as set forth under method (I)o In these methods, however, it i5 not preferred to use a large quantity of the titanium compound. The amount of the titanium compound is preferably about 0.01 to about 1 mole per mole of the , ~ ~7 -~ .
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magnesium compound.
The above methods are typical methods, and many modifications are possible as shown below.
(1) Method (I~ in which the electron donor is caused to be pre~ent when reacting the titanium compound.
(2) A method in which the organic or inorganic inert diluent and the silicon, aluminum, germanium or tin compound are caused to be present dur~ng the reaction;
a method in which these compou~lds are caused to act before the reaction; a method in which these compounds are caused to act between the reactions; a method in which these com-pounds are caused to act after the reactionO A typical example of methods is the method (I-c). These reagents can be used at desired points in the above methods. For example, (2-a) Method in which a halcgenating a~ent such as SiC14 is caused to act on the compound obtained by methods II) and (III).

(3) Method in which the titanium compound is caused to act two or more times:-(3-a) The method in which the titanium compound and the electron donor are reacted ~lith the reaction pro-- duct obtained by any of the methods (I) to (III!.
(3-b) The method in which the titanium compound, the organoalumir.w~ compound and the electron donor are reacted with the reaction product of any one of these ;~ methods ~I) to (III).
A numb~r of other modifications can be made by changing the order of addition of reaction agents, or by :, . . -- 1 ~ --; .
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~)8S996 carrying out a plurality of reactions, or by using ad-ditional reaction agents. In any of such methods~ it is desirable that the halogen, titaniu~ and magnesiwn in the complex (~), the proportion of the electro~ ~onor, the surface area of the complex (A) and the ~-ray spectrum of the cataly3t be within the abo~e range or in the above-mentioned conditions.
Exarnples of the electron donor to be desirably included in the catalyst component (A) are esters, ethers, ketones, tertiary amines, acid halides, and acid anhydrides, which do not. contain active hydrogen. Organic acid esters and ethers are especially preferred, and most preferred are aromatic carboxylic acid esters and all~yl-containing ethers. Typical examples of suitable aromatic carboxylic acid esters include lower alkyl esters such as lower a]1~yl e~ters of benzoic acid, and lower alkyl esters of alkoxy benzoic acidO The term "lower" means the possession of 1 to 4 carbon atoms. Those having 1 or 2 carbon atoms are especially preferredO Suitable alkyl-containing ethers are those containing 4 to ZO carbon atoms such ag dii~oamyl ether and dibutyl ether.
The organometallic compound (B) has a hydrocarbon group directly bonded to the metal, and includes, for example, alkyl aluminwn compounds, alkyl alwninum alkoxides, a~kyl aluminum hydrides, alkyl alwninwn halides, dialkyl zincs, and dialkyl magnesiumsO Preferred among them are ; the organoaluminwn cmmpounds. Specific examples of the organoaluminwn compounds are trialkyl or trialkenyl aluminwns such as Al(C2~5)3- ~l(CH3)3. ~l(c3H7)3-.

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~08s9g6 ; ( 4H9)3 and ~l(C12H25)3; alkyl aluminum compoundg having such a structure that many aluminum atoms are connected through oxygen or nitrogen ato~s, such as (C H )2~10Al(C2H5)?, (C4~9)~10~1lC4~9)2- 2 5 Z
hlMAl(C~5)2; dialkyl aluminun hydrides such as (C2H5)2AlH
~,; 6 5 or (C4Hg)2AlH; dialkyl aluminum halldes such as (C2H5)2 AlCl~ (C2Hs)2AlI or (C4~9)2~1Cl; and dialkyl aluminum alkoxides or phenoxides such as ~C2X5)2Al(OC2H5~ and (C2H5)2Al(OC6H5). Of these, the trialkyl aluminums are most preferred.
Preferably, the organometal.ic compound (B) is used together with an electron donor (C), for example those exemplified hereinabove with regard to the catalyst component ~A). Above all, it is used preferably together with an organic acid ester, especially an aromatic carbo-;~ xylic acid ester containing 8 to l.o carbon atoms such as t methyl benzoate, ethyl benzoate, methyl p-toluate, ethyl ... p-toluate, methyl p-anisate, and ethyl p-anisate. Such an organic carboxylic acid ester serves to maintain the yield of a highly stereoregular polymer at a high level ~ven when the polymerization is performed in the presence of hydrogen.
.~ The titanium complex catalyst component (A), ~,. the organometallic co~pound (B) and the electron donor 'Ij; ' ~;; 25 (C) preferably the organic carboxylic acid may be mixed :;~ in any desired order. The suitable amount of the free organic carboxylic acid ester is not more than 1 mole, ~.~ preferably about 0.01 to 0.5 mole, per metal atom of the ',.', ':

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organometallic compound.
~ ccording to the proces6 of thi~ invention, a-olefins containing at least 3 carbon atoms are polyme-rized or copolymerized in tne presence of a catalyst com-prising (h) the solid titanium complex catalyst componentconsi~ting essentially of magneslum, titanium, halogen and an electron donor, and (B) the organometallic co~pound of a metal of Groups I to -iII of the periodic table with or without (C) the electron donor.
The first-step polymerizatio~ temperature i9 not more than about 50 C. However, in view of the removal of - the heat of polymerization or the rate of polymerization, too low a te~perature i5 not preferred. Usually, the tem-; perature is higher than room tem~eratureO The amount of an ~-olefin polymerized in the first step is at least about 100 millimoles, preferably at leagt about 1000 millimoles, per millimole of titanium atom in the titanium complex cata-ly~t component (A). There is no particular upper limit to the amount of the a-olefin polymerized. The rate of poly-merization increases with increasing amount of the a-olefin polymerized in the first step, but beyond a certain point, the rate of polymerization again tends to decrease. Hence, the amount of t~e a-olefin to be polymerized in the first - step is not more than about 30% by weight of the final pro-duct obtained in the second step.
In the first-step polymerization, it is preferred to cause a molecular weignt controlling agent, preferably hydrogen, to be copresent. The amount of hydrogen fed i~
about 0.5 to about 40 moles, e~pecially about 4 to about `~ - 21 -.' , .

', ~l)S59~6 20 mole/0, b~sed on the a-olefin~
~fter the first step polymerization, the tem-perature is raised, and the second-step polymerization is carried out at a temperature whichiis higher than the first-step polymerization te~perature, preferably at least 10Co higher than t'ne first-step polymeri~ation tempera-ture, more preferably about 50 to 90C., especial~y pre-ferably about 60 to 80C. When the temperature increases beyond about 90C., catalytic activity, bulk density and the ratio of a stereoregular polymer formed all tend to decrease.
In the second-step polymerization, too, the molecular weight of the polymer is preferably adjusted with hydrogenO
There is no particular restriction on the poly-merization pres~ureO Preferably, however, the first-step polymerization pressure is from atmospheric pressure to about 20 k~cm2, and the second-step polymeri3ation pressure is from atmospheric pressure to about 50 kg~cm2.
Preferred ~-olefins are a-olefins containin$ at least 3 carbon atoms such as propylene, l-butene, and 4-methyl-l-pentene. The polymerization may be homopolymeri-zation an~ copolymerization. ~s a comonomer, up to 10 mole% of ethylene may be used. Dienes may al~o be used as comonomers.
In the conventional copolymer~zation of propylene with ethylene, the bulk density of the polymer tends to decrease abruptly with increasing ethylene content in a one-step processO ~owever, the two-step process of this invention 1q:)8S996 makes it possible to afford a polymer having a high bulk denityO In homopolymeri~ation, too, an improvement is achieved in ~ulk density and the ratio of a stereoregular polymer formed, and a marked increase ig observed in the amount yielded of polymer ~,er unit weight of the catalyst per unit time. No clear rea~on can be assigned to the unexpected result of increased catalystic activity, but it i8 presumed that this is a unique feature of the cata-I.yst used in this invention.
The following ~xamples illustrate the present :: t:.invention in ~ore detail.
Example 1 Preparation of catalyst (co~ponent h~
Commercially available anhydrous magnesium chloride (20 g), 6.0 ml of ethyl benzoate and 3.0 ml of silicon tetra-chloride were charged under an atmosphere of nitrogen into a stainless steel (SUS 32) ball mill cyl.inder having an inner capacity of 800 ml and an inside diameter of 100 m~
and containing 100 stainless steel (SUS 32) balls with a diameter of 15 ~ accomodated therein, and were contacted with one another at 125 rpm for 48 hours.
The solid product obtained by the treatment was suspended in 150 ml of titanium tetrachloride. The solid matter was collected by filtration, and washed with purified hexane until no free titanium tetrachloride was detected in the wash liquid, to afford component (A) which contained, as atoms "..6% by weight of titanium, 64.o% by weight of chloride, and 8.9% by weight of ethyl benzoate.

~08S996 Polymerization An autoclave h~ving an available volume of 2 liters was charged with l.O liter of kerosene, 1.8 milli-moles of triethyl aluminum, o.6 millimole of ethyl ben-zoate, and 0.1 millimole, calculated as titanium atom, of the catalyst component ~ set forth above. Hydrogen (250 ml) was added, and while feeding propylene, the system was maintained at 40C. and 4 k$icm2.G for 10 minutes.
In this manner, about 40 g of propylene was polymerized.
Then, o~er the course of about 20 minutes the temperature of this system was raised to 60C., and propylene was con-tinuously fed and polymerized for 20 hours at 70b kgicm2uG.
The solid matter was collected by filtration, washed with hexane, and dried to afford 486 g of polypropylene as a white powder. The powdery polypropylene had a boiling n-heptane extraction re~idue of 9604%, a bulk density of 0.42 g/cc, and an ~) of 2.9. On the other hand~ concent-rating the liquid layer afforded 14.3 g of a soluble polymer.
Examples 2 and 3 Propylene was polymerized using the same catalyst and polymerization procedure as in Example 1 except that the amount of propylene polymerized in the first step was changed as sho~n in Table l. The results are also shown in Table l.

, -- ~8S9~6 Table 1 Amount of Polymeri-propylene zation Amount of f'ed in time in polymer Boiling hmount the first the first finally n-heptane of Bulk Exa- ~t~P step obtained re~idue soluble density ~p~ (g)(minutes) (g) (%) polymer (~ (g,'cc) I_ l 2 10 3 ~74 95.2 12.5 2.7 0.42 3 125 40 536 95o6 14.7 209 0.43 _ __ _ _ Example 4 Propylene was polymerized using the same catalyst and polymerization procedure as in Example 1 except that the polymerization in the second step was carried out at 70co, and the amount of hydrogen added was changed to 150 ml. There was obtained 523 g of polypropylene as a powder which had a boiling n-heptane extraction residue of 95.8%~ a bulk density of 0.38 g,'cc, and an (~) of 2.6.
Concentrating the liquid layer afforded 17.3 of a soluble polymer.
Comparative Examples 1 and 2 Propylene was polynerized for 2.5 hours at 60C.
and 70 cO respectively using the same catalyst and poly-merization procedure as in Example 1 except that the first step was omitted. The amount of hydrogen added waY changed to 150C. when the temperature was 70 c. T~e results are shown in Table 2 together with the results of Example 1.

: : .

l~S9g6 Table 2 _. _ . _ Boiling Polymeri- n-heptane zation Polypro- extrac-~ompara- tempera- pylene tion Soluble Bulk tive ture powder residue polymer density Example (C.) (g) (%) (g) (g~cc) ~) _ __ _ 1 60 412 9202 16.3 0.37 2.6 2 7 422 9103 1704 0.33 2.6 ; I _ _ :
Example l _ 486 9604 14.3 0042 2.9 , .

The results show that ~-hen the first step was performed, an apparent increage in bulk density and stereo-regularity was achieved as comp~red with the case of omit-ting the first step, and une~pectedly, the amount of the polymer formed per unit weight of the catalyst increased markedly. This is an evident effect of the first-step treatment.
Comparative Example 3 This example illustrates the first-step polymeri-~ation performed with a conventional titanium trichloride-type catalyst.
Polymerization An autoclave having an available volume of 2 liters was charged with l.0 liter of kerosene, 6~0 milli-moles of diethyl aluminum chloride, and 200 millimoles of titanium trichloride IAA grade)u Hydrogen ( 400 ml) :~as added, and about 27 g of propylene was polymerized while feeding propylene for 20 minutes at 40co and 4 kg/cm2-G0 Then, over the course of 20 minutes, the temperature - ~6 -- ~8sg96 of the system was raised to 70C., and propylene was continuously fed and polymerized for 4.0 hours at 7.0 kg/cm2-G.
For comparison, the polymerization was performed at 70 C. for 4 hours and 40 minutes without performing the first 3tep polymeri~ationO The results are shown in Table 3.
Table 3 ¦ Boiling Polypro- n-heptane Performance pylene extraction Soluble Bulk of the powder residue polymer densi$y first step I (g~ I (%) (g) (gJcc) ~) No 452 97.1 52.0 0.37 Z.9 Yes 436 96.5 4104 0039 3.0 .

The results show that a slight effect of the first-~tep polymeri7.ation was observed on an increase in bulX density and stereoregularity. However, the effect was far smaller than the effect on the supported titanium tetra-chloride-type catalyst, and it is seen that the effect of the first step is substantially not observed with the con-ventional catalyst. A comparison of Table 2 with Table 3 shows that the use of the two-step procedure exhibits a unique effect on the catalyst cQntaining a titanium catalyst co~ponent.
Example 5 This example illustrates the effect of the first-step polymerization on the random copolymerization of pro-pylene and ethylene in the presence of the catalyst shown ,.:
.

11:)8S996 in Table 1.

Polymerization .

An autoclave having an availab e volume of 2 liters was charged with ~0 liter of kerosene, l.8 milli-moles of triethyl aluminum, 0.42 millimole of ethylbenzoate, and 0.1 millimole, calculated as titanium atom, of the cataly3t component ~. obtained in Exa~ple 1. Hydro-gen (150 ml) was added, and about 15 g of propylene was polymerized while feeding propylene at 40C. and 2 kg.~cm2-~
for 10 minutes.
Then, over the course of 20 minutes, the tem-perature of the system was raised to 60Co ~ and propylene gas containir.g 5.7 mole% of ethylene was continuously fed, - and polymerized for 2 hours at 5.0 kg cm2-G.
For comparison, propylene gas containing 5.9 mole%
of ethylene uas continuously fed, and polymerized at 60 C.
for 2.5 hour~ without performing the fir~t-step polymeri-zation at 40C.
The results are shown in Table 4.

~ Table 4 Performance Powdery Soluble of the first copolymer polymer Bulk density step (g) (g) (g.~cc) ~) . . _ ,,.
No 299 57 0027 2.7 (comparison) Yes 482 58 0.34 2.6 (invention) The results show that the ratio of the soluble polymer to the powdery copolymer was smaller and the bulk .

':

~o8S996 density of the polymer is higher in the case of perform-ing the first step than in the case of omitting the first step. The effect wa~ greater than in the case of homo-polymerization.
Example 6 Preparation of the catal st cornponent A
Y
Commercially available anhydrous magne~ium chloride (0.1 mole) was suspended in 0.3 liter of kerosene, and 0.4 mole of ethanol and Ool mole of ethyl benzoate were added to the suspension at room temperature. Then, 0.3 mole of diethyl aluminum chloride was added at room tem-perature, and the mixture was stirred for 1 hourO The solid portion of the product was collected, washed suf-ficiently with kerosene, suspended in 0.3 liter of a kerosene solution containing 30 ml of titanium tetra-chloride, and reacted at 80C. for 2 hours. ~fter the reaction, the supernatant liquid was removed by decanta-tion, and the solid portion wag wa~hed thoroughly with fresh kerosene. The resulting solid contained, on the basis of atom, ~23 mg of titanium, 582 mg of chlorine and 132 mg of ethyl benzoate.
Polymerizati_ ~n autoclave having an available volume of 2 liters was charged with 1.0 liter of kerosene, 1.6 milli-moles of triethyl aluminum and 005 millimole of ethyl benzoate, and 0.07 mi~limole, calculated as titanium atom, of the catalyst component ~. prepared ahove. ~ydrogen (250 ml) was added, and about 35 g of propylene was poly-merized while feeding propylene at 40C. and 4 kg~cm2-G

for 10 minutes.
Then, over the course of 20 minutes, the tem-perature of the polymerization system was raised to 60co~
and propylene was continuously fed and polymerized for 2.0 hours at 7.0 kg'cm2oG0 For comparison, the above polymerization was performed in one step at 60C. for 25 hours without the first-step polymerization at 40Co The results are sho~m in Table 50 Table 5 Polypro- n-héptane _ . _ Performance pylene extraction Soluble Bulk of the first powder residue polymer density step (g~ (%) (g) (g~'cc) (~) Yes 525 96~2 23~3 o.38 2. 7 (invention) No 382 9200 16~7 0~32 2~5 (comparison) .

Example 7 Preparation of the catalyst co~ponent h Ten grams of the catalyst obtained by the catalyst preparation method of Example 1 was suspended in 150 ml of kerosene, and with stirring, 3~4 millimoles of triethyl aluminum, 13~6 millimoles of ethyl ben7.0ate, and 3.4 milli-moles of titanium tetrachloride were added successively at one-hour intervalsO After the reaction, the solid portion of the product was collected by filtration, washed thoroughly with purified n-hexane, and dried to afford a catalyst component h which contained, as atoms, 20 2%

~085996 by weight of titanium, 60.0% by weight of chlorine, and 10.8% by weight of ethyl benzoate.
Polymerization The polymerization of Example 6 was repeated except that 2.0 millimoles of triethyl aluminum, 1.8 millimoles of ethyl benzoate, and 0.20 millimole, cal-culated as titanium atom, of tne cataly~t component ~.
were addedO
For compari on, the above polymerization was performed in the same way as in Example 6 except that the first step was omitted, and the polymerization time was changed to 2.5 hoursO
The results are sho~m in Table 6.

Table 6 Polypro- n-heptane _ i Performance pylene extraction Soluble Bulk of the first powder residue polymer density step (g) (g) (g) (g;'cc) (~) Yes 537 97.0 27~7 0.44 3-o No 364 92.8 11.4 o.38 Z.9 Example 8 Preparation of catalyst component A
Commercially available anhydrous magnesium chioride (20 g), 5.3 g of n-butyl benzoate and 20 3 g of p-cresol were charged into a stainless steel (SUS 32) ball mill having an inside diameter of 100 m~ and an inner capacity of o~8 liter and including 2~8 kg of stainless - 31 ~

.

t3S996 steel (SUS 32) balls with a diameter of 15 mm in a nitro-gen atmosphere, ar.d co-pulverized for 24 hours at an impact acceleration of 7G. The resulting co-pulverized product (10 g) was suspended in 100 ml of titanium tetra-chloride, and after elevating the temperature of thesuspension to 100Co ~ it w~s stirred for 2 hours. Then, the solid was collected by hot filtration, washed with kerosene and hexane, and dried to afford a titanium-con-taining solid catalyst component which contained 2.8%
by weight of titanium, 61~0% by weight of chlorine and 20.0% by weight of magne siumO
Polymeri~ation The inside of a 7.-liter autoclave was purged with propylene, and then it was cnarged ~ith 750 ml of hexane deprived fully of oxygen and moisture, 3~75 milli-moles of triisobutyl aluminum, 1.25 millimoles of ethyl p-toluate, and 38 mg of the solid catalyst component pre-pared as above. They were stirred for 5 minutes at 35Co and about 10 g of propylene was polymerized in the first stepv Then, the polymerization system was heated to 55C.
over the course of about 5 minutes, and a propylene gas containing 6.2 mole/0 of ethylene was continuously fed, &nd polymerized for 2.0 hours at 2.5 kg~cm2.G. The results are sho-~n in Table 7.
Example 9 Preparation of a catalyst component ~h~
~ nitrogen-purged flask was charged with 50 ml of toluene ~nd 12 ml of silicon tetrachloride, and 50 ml of a normal butyl ether solution containing 0~05 mole of n-butyl magnesium chloride was added dropwise to the mixture at 10C. over the course of 2 hours. After the addition, the temperature of tne mixture ~as raised to 60C., and stirred at this temperature for 2. hoursO The ~olid matter was collected by filtration, fully washed with hexane, and dried. The powdery solid was suspended in 50 rnl of kerosene, and l.l g of ethyl o-toluate and o.8 g of ethyl cyclohexanecarboxylate were addedO The mixture was stirred at 80Co for ? hours. The super-natant was removed by decantation, and decantation wasfurther carried out using fres7n solvent until complete washing was effected. Titanium tetrachloride (100 ml) was added to 30 ml of the suspension containing a solidO
The mixture was heated to 110C., and then stirred for 2 hours. The supernatant was removed hy decantation, and lO0 ml of titaniur,l tetrachloride was further added. The mixture was stirred at 130Co for 2 hours, and the solid matter was collected by hot filtration~ It was fully washed with hot kerosene and hexane, and dried to afford a cata-lyst component (A) which contained, a~ atoms, 1.5% byweight of titaniwn, 6800% by weight of chlorine, and 22.0%
by weight of magnesiumO
Polymerization ~ propylene gas containing ethylene was poly-merized under the same conditions as in Exarnple 8 except that tri-n-hexyl aluminum was used instead of triisobutyl aluminumg ethyl p-anisate was used instead of the ethyl p-toluate, and 67 mg of the solid catalyst component pre-pare~ as above was usedO The results are shown in Table 7.

- ~V85996 Example 10 Pr_paration of a catalyst component (~) A reactor was charged with 50 ml of a butyl ether solution containing 0.05 mole of n-butyl magnesium S chloride in an atmosphere of nitrogen, and 0.05 mole of 2,6-dimethyl phenol was added dropwise. The mixture was heated to 70C., and stirred for 2 hours. The butyl ether was removed by decantation, and 50 ml of purified kerosene was addedO Furthermore, OoOl mole of ethyl p-anisate was added dropwiseO The mixture was heated to 80Co, and stirred for 2 hours at tnis temperatureO The solid portion was collected by filtration, washad with purified hexane, and dried under reducecd pressureO The resulting product was suspended in 100 m] of titanium tetrachloride, and with stirring, reacted for 2 hours at 100C. The supernatant was removed bJ decantation, and 100 ml of titanium tetra-chloride wa~ added. The mixture was stirred for 2 hours at 100C , and tne solid portion was collected by hot filt-ration. The solid portion was fully washed with purified hexane, and dried under reduced pressure to afford a titanium-containing solid catalyst component -~hich con-tained 2.9% by weight of titanium, 59.0% by weight of chlorine, and 1900% by weight of ma~nesium.
Polymerization A 2-liter autoclave was charged with 750 ml of hexane deprived of oxygen and moisture. While passing a propylene gas containing 70 39 mole% of ethylene, 30 75 millimoles of an organoaluminum co~pouncl having an average composition Et2 9Al(OEt)o 1~ 1025 millimoles of methyl - ~ , :

p-toluate and 37 ~g of the solid catalyst component prepared as above were charged~ T'ne autoclave was sealed, and 0.2NQ of H2 was introduced. The contents ~ere stirred at 35C. for 5 minutes to polymerize 12 g of the propylene ~as. Analysis showed that the p~lymor:thus formed in the first step contained 201 mole~/, of ethylene. The polymerization system was then heated to 60C. over the course of about 7 minutes. k propylene gas containing 7.39 mole% of ethylene was continuously fed, and poly-merized for 2.0 hours at a total pressure of 2.5 kg'cm2.G.
Tne results are sho~nn in Table 7.
Example 11 Preparation of a cata]yst component A
Mg(O ~ )2 was synthesi3ed by the reaction of commercially available ~g(OCH3)~ with phenol. h stainlesssteel ball mill cylinder having an inner capacity of Oo8 liter and an inside diameter of 100 mr~ and including 2.8 kg of stainless steel (SUS 32~ balls with a diameter of 15 mm was charged with 0.2 mole of Mg~O ~ )2 and 0.033 mole of n-octyl ben~oate in an atmosphere of nitrogen, and they were co-pulverized for 24 hours at an i~pact acceleration of 7G. The resulting solid product was sus-pended in 200 ml of titanium tetrachloride, and the sus-pension was stirred at 100Co for 2 hours. Then, the solid portion was collected by hot filtration, washed fully with hexane, and dried to afford a titanium-contain-ing solid catalyst component containing 2.80/~ by weight of titanium, oO.0% by ~eight of chlorine and 2100~/o by weight of magnesium.

lOt~S9~6 Polymerization A. propylene gas containing ethyl.ene wag poly-merized under the same conditions as in Example 10 except that 37 mg of the titanium-containinS solid catalyst component prepared as above was used, 3~ 75 millimoles of the organoaluminum compound having an a~erage composition Et2 9hlHo 1 was used instead of the co.~pound Et2 9hl(0Et)o 1 and the amount of the propylene gas polymerized in the first step was 15 g. Tne results are shown in Table 7.
Example 12 Polymerization Into a 2-liter autoclave were charged 3075 milli-moles of diethyl aluminum chloride, 3O 75 millimoles of n-butyl magnesium chloride synthesized in ~erosene, 1025 15 millimoles of methyl p-toluate, and 37 mg of the titanium-containin~ solid catalyst component prepare~ in ~xample 11 in the order stated in an atmosphere of propyleneO The autoclave was sealed, and 002 N~ of H2 was charged. By stirring the contents at 35Co for 5 minutes, 9 g of the propylene gas was polymerized in the first stepO Tne polymerization system was heated to 60C. o~er the course of 5 minutesO h propylene gas containing 6 D 58 mole% of ethylene was continuously fed, and polymeri~ed at 60co and ~05 kg'cm20G-for 2 hours. The results are sho~n in Tab~e 70 ~ 36 ~

108S9g6 Table 7 _. _ _ Powdery Soluble _ copolymer polymer Bulk density Melt Exar.lple (g) (g) (g,'cc) index . _ ___ .
8 98.~ 709 0.29 1406 9 96.4 7.9 o.30 24.5 175.0 13. 9 0029 16 . 2 41 . 8 15 o 3 o. 30 14 . 9 12 12~. 9 9.6 oO 30 5 o 5

Claims (9)

WHAT WE CLAIM IS:

1. A process for preparing .alpha.-olefin polymers or copolymers by polymerizing or copolymerizing .alpha.-olefins containing at least 3 carbon atoms at room temperature or a higher temperature under a pressure of about 1 to 100 kg.cm2 in the presence of a catalyst comprising (A) a solid titanium complex catalyst component consist-ing essentially of magnesium, titanium, halogen and an electron donor, and (B) an organometallic compound of a metal of Groups I to III of the periodic table, wherein the polymerization or copolymerization is carried out in two steps:
(a) a first step where at least about 100 milli-moles, per millimole of titanium atom, of an .alpha.-olefin is polymerized or copolymerized at a temperature of less than about 50°C. to form a polymer or copolymer the amount of which is not more than about 30% by weight based on the final product obtained in the second step, and (b) a second step where the final product is formed at a temperature higher than the temperature of the first step and from about 50°C. to about 90°C.

2. The process of claim l wherein the polymerization or copolymerization is carried out in the further presence of an electron donor (C).

3. The process of claim 1 wherein the halogen/titanium mole ratio of the component (A) exceeds about 4, and when the component (A) is washed with hexane at room tempera-ture, titanium is not substantially removed from it.

4. The process of claim 1 wherein the magnesium/titanium mole ratio is at least about 3.

5. The process of claim 1 wherein the electron donor/titanium mole ratio of the component (A) is about 0.2 to about 6.

6. The process of claim 1 wherein the electron donor is a member selected from the group consisting of ketones containing 3 to 15 carbon atoms, aldehyde contain-ing 2 to 15 carbon atoms, organic acid esters containing 2 to 18 carbon atoms, acid halides containing 2 to 15 carbon atoms, ethers containing 2 to 20 carbon atoms, acid amides, amines and nitriles.

7. The process of claim Z wherein the electron donor (C) is an organic acid ester containing 2 to 18 carbon atoms.

8. The process of claim 1 wherein the component (B) is an organoaluminum compound,

9. The process of claim 1 wherein the temperature of the second step is at least about 10°C. higher than the first-step temperature and is from about 60°C. to about 80°C.