NO151661B - PROCEDURE FOR PREPARING PROPYLENE POLYMERS OR COPOLYMERS - Google Patents

Description

The present invention relates to a method thereof

species specified in claim l's preamble.

It has been known that a catalyst consisting (A) of a

solid titanium complex, with the catalyst component mainly

consists of magnesium, titanium, halogen and an electron donor

tor and (B) an organometallic compound of a metal from groups I - III in the Periodic Table can be used for the production of α-olefin polymers or copolymers with good stereoregularity with outstanding catalytic activity, and there are several proposals regarding the use of fa-

st titanium complex catalyst components (A) prepared from different combinations of catalyst-forming components

ter and/or under specified combinations of catalyst-forming combinations (e.g. BRD official document no.

2,230,728 corresponding to Japanese official document no. 16986/73 and French patent no. 2,143,347, BRD official document no. 2,347,577 corresponding to Japanese official document no. 86482/74, British pa-

patent no. 1,435,768 and French patent no. 2,200,290, BRD off. document no. 2,504,036 corresponding to Japanese official document no. 108385/75 and 20297/76, and French patent no. 2,259,842, BRD official document no. 2,553,104 corresponding to Japanese official document no. 126590/ 75, Dutch patent no. 75.10394 corresponding to yes-

Spanish official document no. 28189/76 and French patent no. 2,283,909, Japanese official document no. 57789/76, Japanese official document no.

64586/76, BRD official document no. 2,605,922 corresponding to Japanese official document no. 92,885/76, Japanese official document no. 127185/76,

and Japanese official document no. 136625/76).

However, there has been no positive proposal regarding a two-stage polymerization process using the catalyst component (A) because the two-stage process is obviously disadvantageous over a one-stage process in commercial operations, and no advantages that would override

set such a disadvantage can be expected from the two-step process.

Some suggestions regarding the two-step polymerization of pro-

pylene with conventional titanium trichloride type catalysts such as a titanium trichloride composition obtained by reduc- .

tion of titanium tetrachloride with metallic aluminum or other reducing agents are known (e.g. Japanese patent no. 32312/72, Japanese patent no. 14865/74 and British patent no. 1,359,844 corresponding to Japanese official document no. 2439/72 ).

However, it is well known that in the polymerization of propylene using these conventional titanium trichloride type catalyst components different from the aforementioned catalyst component A, the use of high reaction temperatures in an attempt to increase the polymerization activity reduces the crystallinity of the polymer, and further results in of low reaction temperatures in an attempt to increase crystallinity inevitably results in reduced polymerization activity of the catalyst. In consideration of the balance between polymerization ionic activity and crystallinity, temperatures of approx. 60-70°C as most suitable for the polymerization of propylene. It has been found that when propylene is polymerized with these conventional titanium trichloride type catalyst components at ca. 60-70°C, there is no significant difference in the result between a one-stage polymerization process and a two-stage polymerization process involving a first-stage polymerization carried out at a low temperature and a second-stage polymerization carried out at approx. 60-70°C. Specifically, the amount of polymer formed per unit weight catalyst per unit time essentially the same for both processes, and in the case of a batch reaction, the proportion of stereoregular polymer formed and the bulk density of the polymer are essentially the same for both or somewhat higher in the two-step process. Consequently, no significant advantage can be seen in using the two-step process while accepting the operational disadvantage.

When the second step of the two-step polymerization process using the conventional titanium trichloride catalyst component is carried out at a temperature of more than about 80°C, the amount of polymer obtained, the bulk density of the polymer and the yield of a strong stereoregular polymer tend to decrease as shown, e.g. by the experimental data in Japanese Patent No. 1486 5/74 cited above. The use of such high temperatures is not practical.

The present inventors have made investigations to obtain improved results in the polymerization of propylene or the copolymerization of propylene with up to 10 mol% ethylene using a solid titanium complex catalyst component (A) consisting mainly of magnesium, titanium, halogen and an electron donor which is of a different type from the conventional titanium trichloride type catalyst components. These investigations led to the unexpected discovery that the use of a two-stage polymerization process with catalyst component (A) under specific conditions can provide improved catalytic activity and stereoregularity and increased bulk density.

It was also found that when the catalyst component (A) is used in the aforementioned two-stage polymerization method with the conventional titanium trichloride catalyst^ where the second stage is carried out at approx. 60-70°C, within which temperature range no significant advantage is detected using the operationally disadvantageous two-step process compared to the one-step process, a marked increase in catalytic activity can be obtained which is completely unexpected from the first polymerisas ion step . These unexpected results cannot be anticipated from the results obtained using the two-step polymerization process with conventional titanium trichloride catalyst.

It has also been found that at polymerization temperatures of at least 70°C, e.g., more than 80°C, where the amount of crystalline polypropylene tends to increase, the reaction mixture can be prevented from becoming viscous as a result of an increase in the amount of amorphous polymer and the considerable reduction in the yield of the polymer can also be avoided

The excellent results obtained by the method according to the present invention which uses the catalyst component (A) cannot be expected based on the results in the two-stage polymerization process with the conventional titanium trichlorine catalysts.

It is therefore an object of this invention to provide a markedly improved process for the polymerization of propylene or the copolymerization of propylene with up to 10 mol% ethylene in two stages.

The method is characterized by what is stated in the characterizing part of claim 1, namely that the polymerization is carried out in

(a) a first step where at least 100 mmol per mmol titanium atom of propylene is polymerized or copolymerized with ethylene at a temperature of less than 50°C to form a polymer or copolymer whose amount is not more than 30% by weight based on the final product obtained in the second step, the titanium catalyst component (A ) is a solid titanium complex catalyst component consisting of magnesium, titanium, halogen and an electron donor which is an organic acid ester or an ether, and where the halogen/titanium molar ratio is at least 8, the magnesium/titanium molar ratio is at least 3, the electron donor/titanium molar ratio is 0.2-6, and the specific surface area of the solid component is at least approx. 40 m 2 / g, and (b) a second step, where it is polymerized at a temperature which is higher than the temperature in the first step and which is within the range 50-90°C. The solid complex titanium component (A) is obtained by intimately bringing a magnesium compound (or magnesium metal), a titanium compound and an electron donor into contact by such means as heating or copulverization. The solid complex has a halogen/titanium molar ratio greater than 8 and essentially does not allow liberation of a titanium compound by washing with hexane at room temperature. The chemical structure of this solid complex is not known, but preferably the magnesium atom and the titanium atom are firmly bound, e.g. with a common halogen. The solid complex may, depending on the production method, contain another metal atom such as aluminium, silicon, tin, boron, germanium, calcium and zinc, an electron donor or an organic group

pe that can be attributed to such. It may also contain an organic or inorganic inert diluent such as LiCl, CaC03, BaCl2/Na2C03, SrCl2, B2°3' Na2S04, Al203, Si02, Ti02, NaB407, C<a>3(P04)2, CaS04, Al^ SO^) 3, CaCl2, ZnCl2, polyethylene, polypropylene and polystyrene. Preferably, the solid complex is treated with an electron donor. In the solid, complex titanium component (A), the halogen/titanium molar ratio exceeds at least approx. 8, and the magnesium/titanium molar ratio is at least approx. 3, preferably approx. 5-50, and the electron donor/titanium molar ratio of approx. 0.2-6, preferably approx. 0.4-3, particularly preferred approx. 0.8-2. Furthermore, the specific surface area of the solid component is 40 m 2 /g, and particularly preferably at least approx. 100 m 2 /g. It is also desirable that the X-ray spectrum of the solid complex (A) shows an amorphous character regardless of the magnesium starting compound, or that it is in a more amorphous state than ordinarily occurs; physically available grades of magnesium dihalide.

The solid titanium complex catalyst component (A) can be produced by known means per se. These funds are included in e.g. the patents previously mentioned herein regarding the use of solid titanium complex catalyst components (A),

and also in Japanese Patent Applications Nos. 4056/76, 16589/76 21179/76, 63536)76, 76085/76 and 114836/76.

Typical methods described in these documents include the reaction of at least one magnesium compound (or metallic magnesium), an electron donor and a titanium compound.

An organic acid ester or an ether is used as an electron donor.

Suitable magnesium compounds used for the formation of the solid, complex titanium compound (A) are those which contain halogen and/or organic groups. Specific examples of such magnesium compounds include magnesium s rum d i ha 1 ogenides, magnesium methoxy halides, magnesium aryl oxy halides, magnesium hydroxy halides, magnesium di alkoxides, magnesium di aryl oxides, magnesium alkoxy aryl oxides, magnesium acyloxy halides, magnesium alkyl halides, magnesium aryl halides, magnesium dialkyl compounds, magnesium diaryl compounds and magnesium alkyl alkoxides. They can exist in the form of adducts with the aforementioned electron donors. Or they can be double compounds containing other metals such as aluminium, tin, silicon, germanium, zinc or boron. E.g. there may be double compounds of halides, alkyl compounds, alkoxyhalides, aryloxyhalides, alkoxides and aryloxides of metals such as aluminium, and the magnesium compounds exemplified above. Or they could be double compounds in which phosphorus or boron is bound to magnesium metal through oxygen. These magnesium compounds can be a mixture of two or more. Generally, the compounds exemplified above can be expressed by simple chemical formulas, but sometimes, depending on the production method of the magnesium compounds, they cannot be expressed by simple formulas. They are usually considered to be mixtures of the aforementioned compounds. E.g. are compounds obtained by a method which if-! comprises reaction of magnesium metal with an alcohol or phenol in the presence of a halosilane, phosphorus oxychloride or thionyl chloride and a method comprising the pyrolysis of Grignard compounds, or their cleavage with compounds having a hydroxyl group, a carbonyl group, an ester bond, an ether bond, etc. considered as mixtures of different compounds according to the amounts of the reactants or the degree of conversion. These compounds can of course be used in this invention.

Various methods of preparing the magnesium compounds exemplified in the above are known, and products of any of these methods may be used in the present invention. Furthermore, the magnesium compound before use can e.g. treated by a method which involves dissolving it alone or together with another metal compound in ether or acetone, and then evaporating the solvent or placing the solution in an inert solvent and thereby separating the solid.

A method can also be used which includes mechanical pulverization of at least one magnesium compound with or without another metal compound.

Preferred among these magnesium compounds are magnesium dihalides, aryloxyhalides and aryloxides, and double compounds of these with aluminum, silicon, etc. More specifically earthMgCl2, MgBr2# Mgl2, MgF2, MgCKOCgHg), Mg(OC6H5)2, MgCl(OC6H4-2-CH3 ), Mg(0CgH4-2-CH3)2, (MgCl2)x[Al(OR)nCl3_nJ

and (MgCl2)x[Si(OR)mCl4_m]y. In these formulas, R is a hydrocarbon group such as an alkyl or aryl group and m or n R groups which are the same or different, and 0=n=2, 0=m-4, and x and y are positive numbers. MgCl 2 and its complexes or double compounds are particularly preferred.

Suitable titanium compounds used for the formation of the solid complex titanium compound (A) are tetravalent titanium compounds of the formula Ti(OR) X. , in which R is a hydrocarbon group, for-

y *—g ;preferably an alkyl group containing 1-6 carbon atoms, ;X is a halogen atom and 0-g=4. Examples of the titanium compounds are titanium tetrahalides such as TiCl4, TiBr4 or Til4, alkoxy-titanium trihalides such as Ti(OCH3)Cl3, Ti (0C2H5) Cl3, Ti (0 n-| C4H9)C13, Ti(OC2H5)Br3 and Ti(0 iso -C^Hg)Br3, Alkoxytlandihalides such as Ti (OCH3 ) 2C12 , Ti (OC^ ) 2C12 , Ti (0 n-C4H9)2Cl2 and Ti(OC2H^)2Br2, tri- oxytitanium monohalides such as Ti(OCH3)3Cl, Ti(OC2H5)3Cl, Ti (0 n-C4H9)3Cl and Ti (OC^H^Br; and tetraalkyloxytitanium compounds such as Ti(OCH3)4, Ti(OC2H5)4 and Ti(0 n-C4Hg)4. Among these the titanium tetrahalides are preferred^ and particularly preferred is titanium tetrachloride. ;There are various examples of reaction of the magnesium compound (or metallic mag.ensium), the electron donor and the titanium compound to prepare the titanium complex catalyst component (A), and typical ones are described below. ;[I] Process which includes reacting the magnesium compound with the electron donor and then reacting the reaction mixture with the titanium compound:- ;(I-a) Process way [I] with copulverization of the magnesium compound and the electron donor:- ;The electron donor which is added at the time of the copulverization need not be in a free state, and can be in the form of an adduct with the magnesium compound. At the time of co-pulverization, further components which may be involved in the complex titanium component (A), e.g. the aforementioned organic or inorganic inert diluents, a halogenating agent such as a halogen compound of silicon, a silicon compound such as polysiloxane, and a compound of aluminum, germanium or tin, or part of the titanium compound be simultaneously present. Or the electron donor can be in the form of an adduct (complex compound) with such a compound. The amount of electron donors used is preferably around 0.005 - 10 mol, more preferably around 0.01 - 1 mol per moles of magnesium compound. The copulverization can be carried out using conventional devices such as a rotating ball mill, a vibrating ball mill or a crushing mill. If the rotary ball mill is used, it contains 100 stainless steel (SUS 32) balls with a diameter of 15 mm in the ball mill cylinder which has an internal capacity of 800 ml and an internal diameter of 100 mm and is made of stainless steel (SUS 32) and 20 - 40 g of the material to be treated is placed therein, and it is advisable to perform the pulverization for at least 24 hours, preferably at least 48 hours at a rotational speed of 12 5 rpm. The temperature during the pulverization treatment is normally room temperature to approx. 100°C. The copulverized product can also be reacted with the titanium compound by copulverizing agents. However, it is preferred to distribute the copulverized product in at least approx. 0.05 mol, preferably approx. 0.1 - 50 mol per mol magnesium compound of a liquid titanium compound with or without an inert solvent without copulverization. The reaction temperature is from room temperature to approx. 200°C and the reaction time is from 5 min. to 5 hours. The reaction can of course be carried out under conditions outside these specified ranges. After the reaction, the reaction mixture is hot-filtered at a high temperature of e.g. around 60 - 150°C to isolate the product which is then thoroughly washed with an inert solvent before use in polymerization. ;(I-b) Process [I] without the copulverization of the magnesium compound and the electron donor:- ;Normally, the magnesium compound is reacted with the electron donor in an inert solvent, or the magnesium compound is dissolved or slurried in the liquid electron donor for reaction. It is possible to use an embodiment in which metallic magnesium is used as a starting material and is reacted with the electron donor to form a magnesium compound. The amount of electron donor used is preferably approx. 0.01 - 10 mol., especially approx. 0.05 - 6 mol per moles of magnesium compound. The reaction proceeds sufficiently at a reaction temperature from room temperature to approx. 200°C for 5 min. to approx. 5 hours. After the reaction, the reaction mixture was filtered or evaporated and washed with an inert solvent to isolate the product. The reaction of the reaction product with the titanium compound can be carried out in the same way as described under (I-a)'. (I-c) Process comprising reacting the reaction product between the magnesium compound and the electron donor with a compound selected from organoaluminum compounds, silicon compounds and tin compounds, and then reacting the resulting product further with the titanium compound:- ;This method is a special embodiment of the method (I-b). In general, complexes obtained by method (I-a) have better properties, but some of the complexes obtained by method (I-b) have worse properties than those obtained by method (I-a). The properties of such complexes can be very effectively improved by carrying out method (I-c), in which the organoaluminium compound, the silicon compound or the tin compound is reacted before the reaction with the titanium compound. Examples of organoaluminum compounds that can be used in this method are trialkylaluminum compounds, dialkylaluminum hydrides, dialkylaluminum halides, alkylaluminum sesquihalides, alkylaluminum dihalides, dialkylaluminum alkoxides or phenoxides, alkylaluminum uroalkoxyhalgenides or phenoxyhalides and mixtures thereof. Among these, the dialkylaluminum halides, the alkylaluminum susquihalides, the alkylaluminum dihalides and mixtures thereof are preferred. Specific examples of these include triethylaluminum, triisobutylaluminum, diethylaluminum hydride, dibutylaluminum hydride, diethylaluminum chloride, diisobutylaluminum bromide, ethylaluminum sesquichloride, diethylaluminum ethoxide, ethylaluminum ethoxychloride, ethylaluminum dichloride and butylaluminum dichloride. ;Silicon or the tin compounds, e.g. silicon or tin-halogen compounds or organic compounds are compounds which contain at least one halogen or hydrocarbon group directly linked to silicon or tin, and may further contain hydrogen, an alkoxy group, a phenoxy group etc. Specific examples include silicon tetrahalides, tetraalkyl silicon compounds, silicon alkyl halides, silicon alkyl hydrides, tin tetrahalides, tin alkyl halides, and tin hydride halides. Among these, silicon tetrachloride and tin tetrachloride are preferred. The reaction of the resulting reaction product between the magnesium compound and the electron donor with the organoaluminum compound, the silicon compound or the tin compound can be carried out in an inert solvent. Such a compound is used in an amount of preferably approx. 0.1 - 20 mol, more preferably approx. 0.5 - 10 mol per moles of magnesium compound. The reaction is preferably carried out at a temperature from room temperature to approx. 100°C for 5 min. - 5 hours. After the reaction, the reaction mixture is preferably thoroughly washed with an inert solvent and then reacted with the titanium compound. The reaction of this reaction product with the titanium compound can be carried out according to the method described under (I-a). ;[II] Method comprising simultaneous reaction of the magnesium compound, the electron donor and the titanium compound. ;[III] Method which comprises reacting the reaction product between the titanium compound and the electron donor with the magnesium compound. The reactions in these methods [II] and [III] are preferably carried out by copulverization. The pulverization conditions and the proportions of the raw materials are the same as stated under method [I]. In these methods, however, it is not preferred to use a large amount of the titanium compound. The amount of the titanium compound is preferably approx. 0.01 - 1 mole per moles of magnesium compound. ;The above mentioned methods are typical methods and many modifications are possible as shown below. (1) Method [I], in which the electron donor is present during reaction of the titanium compound. (2) A method in which the organic or inorganic inert diluent and the silicon, aluminum, germanium or tin compound are present during the reaction; a method in which these compounds act before the reaction; a method in which these compounds act between the reactions; a method in which these compounds act after the reaction. A typical example of the methods is method (I-c). These reagents can be used at desired locations in the above methods. E.g., (2-a) Process in which a halogenating agent such as SiCl^ is allowed to act on the compound obtained by methods [I], [II] and [III]. ;(3) Process in which the titanium compound is allowed to act two or more times:- ;(3-a) The process in which the titanium compound and the electron donor are reacted with the reaction product obtained by one of the methods [I] - [III]. (3-b) The method in which the titanium compound, the organoaluminum compound and the electron donor are reacted with the reaction product from any of these methods [I] - [III]. ;Several other modifications can be made by changing the order of addition of the reaction reactants or by performing more reactions, or by using additional reaction reagents. In any such method, it is desirable that the halogen, titanium and magnesium in the complex (A), the proportion of the electron donor, the surface area of the complex (A) and the X-ray spectrum of the catalyst lie within the above range or within the above conditions. Examples of the electron donor which is desirably included in the catalyst component (A) are organic acid esters and ethers. Particularly preferred are aromatic carboxylic acid esters and alkyl-containing ethers. Typical examples of suitable aromatic carboxylic acid esters include lower alkyl esters such as lower alkyl esters of benzoic acid and lower alkyl esters of alkoxybenzoic acid. The term "lower" means the presence of 1 - 4 carbon atoms. Those with 1 or 2 carbon atoms are particularly preferred. Suitable alkyl-containing ethers are those with 4-20 carbon atoms such as diisoamyl ether and dibutyl ether. ;The organometallic compound (B) has a hydrocarbon group directly bound to the metal and includes e.g. alkyl aluminum compounds, alkyl aluminum alkoxides, alkyl aluminum hydrides, alkyl aluminum halides, dialkyl zinc compounds and dialkyl magnesium compounds, Preferred among them are the organoaluminum compounds. Specific examples of organoaluminum compounds are trialkyl or trialkenyl aluminum compounds such as A1(<C>2H5)3, A1(CH3)3, A1(C3H7)3, Al(C4Hg)3 and A1(C12H25)3; alkyl aluminum compounds with such a structure that several aluminum atoms are connected through oxygen or nitrogen atoms, such as (C2H5)2A10A1(C2H5)2, (C^Hg } 2A10Al (C^Hg) 2 and (C^,) 2 ;A1NA1 (C2H5) 2 ; dialkylaluminum hydrides such as (C2H5i2AlH ;Vs ; or (C4Hg)2AlH; dialkylaluminum halides such as (C2H5)2 A1C1, (C2H5)2A1I or (C4Hgi2AlCl; and dialkylaluminum oxides or phenoxides such as (C2H5)2 Al ( OC2H51 and (C2H5)2A1-(OCgH^). Among these, the trialkylaluminum compounds are most preferred. ;Preferably, the organometallic compound (Bi) is used together with an electron donor (C), e.g., those exemplified in the above with regard to to the catalyst component ;(A).. Above all, it is preferably used together with an organic acid ester, especially an aromatic carboxylic acid ester ;containing 8 - 18 carbon atoms such as 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 keep the yield of a strong stereoregular polymer at a high level even when the polymerization is carried out in the presence of hydrogen. The titanium complex catalyst component (A), the organometallic compound (B) and the electron donor (C), preferably the organic carboxylic acid can be mixed in any desired order^ The suitable amount of free organic carboxylic acid ester is not more than 1 mol, preferably approx. 0.01 - 0.5 mol per metal atom of the organometallic compound. According to the process of this invention, propylene is polymerized or copolymerized with up to 10 mol% ethylene in the presence of a catalyst comprising (A) the solid titanium complex catalyst component consisting mainly of magnesium, titanium, halogen and an electron donor, and (B) the organometallic compound of a metal from groups I-III in the Periodic Table with or without (C) the electron donor. ;The first-stage polymerization temperature is less than 50°C. However, due to the removal of heat from the polymerization or the rate of polymerization, too low a temperature is not preferred. Normally the temperature is higher than room temperature. The amount of a polymerized propylene in the first step is at least approx. 100 mmol, preferably at least approx. lOOO mmol; per mmol titanium atom in the titanium complex catalyst component (A). There is no particular upper limit regarding the amount of polymerized propylene. The rate of polymerization increases with increasing amount of polymerized propylene in the first stage, but above a certain point the rate of polymerization tends to decrease again. Therefore, the amount of propylene to be polymerized in the first step is no more than approx. 30% by weight of the final product obtained in the second step. In the first stage polymerization it is preferred to have a molecular weight control reagent, preferably hyrogenic, present at the same time. The amount of added hydrogen is approximately 0.5-40 mol%, in particular 4-20 mol% based on propylene. After the first polymerization step, the temperature is increased and the second polymerization step is carried out at a temperature that is higher than the temperature of the first polymerization step, preferably at least 10°C higher than the temperature of the first polymerization step, and is between 50-90°C and especially approx. 60-80°C. When the temperature is increased past approx. 90°C, the catalytic activity, bulk density, and ratio of stereoregular polymer formed all tend to decrease. In the second polymerization step, it is also preferred that the molecular weight of the polymer is adjusted with hydrogen. ;There is no particular limitation of the polymerization pressure. Preferably, the first polymerization step pressure is from atmospheric pressure to about 20 kg/cm 2 , and the pressure of the second polymerization step is from atmospheric pressure to approx. 50 kg/cm 2. In the conventional copolymerization of propylene with ethylene, the bulk density of the polymer tends to decrease suddenly with increasing ethylene content in a one-step process. However, the two-step process of this invention makes it possible to obtain a polymer with a high bulk density. In homopolymerization, an improvement in bulk density and the ratio of a stereoregular formed polymer is also achieved, and a marked increase is observed in the amount of polymer obtained per weight unit of catalyst per unit of time. No clear reason can be seen for the unexpected result of increased catalytic activity, but it is believed that this is a unique feature of the catalyst used according to this invention. The following examples illustrate the present invention in more detail. ;Example 1 ;Production of catalyst (component A). ;Commercially available anhydrous magnesium chloride (20 g), 6.0 ml of ethyl benzoate and 3.0 ml of silicon tetrachloride were charged under an atmosphere of nitrogen into a stainless steel (SUS 32) ball mill cylinder with an internal capacity of 800 ml and a inner diameter of 100 mm which contained 100 stainless steel (SUS 32) balls having a diameter of 15 mm therein and were brought into contact with each other at 125 rpm for 48 hours. The solid product obtained during the treatment was suspended in 150 ml of titanium tetrachloride. The solid was collected by filtration and washed with purified hexane until no more titanium tetrachloride could be detected in the wash to give component (A) containing on an atomic basis 1.6 wt% titanium, 64 wt% chlorine. ; and 8.9% by weight of ethyl benzoate. ;Polymerization ;An autoclave with a useful volume of 2 1 was filled with 1 1 of kerosene, 1.8 mmol of triethylaluminium, 0.6 mmol of ethyl benzoate and 0.1 mmol, calculated as titanium atoms, of catalyst component A as described above. Hydrogen (250 ml) was added and during the addition of propylene the system was maintained at 40°C and 4 kg/cm 2 . G for 10 min.. In this way approx. 40 g propylene polymerized. Then in the course of approx. 20 min. the temperature in this system increased to 60°C, propylene was continuously supplied and polymerized for 20 hours at 7 kg/cm 2. G. Det. the solid was collected by filtration, washed with hexane and dried to give 486 g of polypropylene as a white powder. The powdered polypropylene had a boiling n-heptane extraction residue of 96.4%, a bulk density of 0.42 g/cm, 3 and a [ r)] of 2.9. On the other hand, concentration of the liquid layer gave 14.3 g of a soluble polymer. ;Examples 2 and 3;Propylene was polymerized using the same catalyst and polymerization method as in Example 1 except that the amount of polymerized propylene in the first step was changed as shown in Table 1. The results are also shown in Table 1. ; Example 4: Propylene was polymerized using the same catalyst and polymerization method as in example 1, with the exception that the polymerization in the second step was carried out at 70°C, and the amount of added hydrogen changed to 150 ml. 523 g of polypropylene were obtained as a powder with a boiling n-heptane extraction residue of 95.8%, a bulk density of 0.38 ;3 ;g/cm and a [7)] of 2.6. Concentration of the liquid layer gave 17.3 g of a soluble polymer. Comparative Examples 1 and 2 Propylene was polymerized for 2.5 hours at 60°C and 70°C respectively using the same catalyst and polymerization procedure as in Example 1, except that the first step was omitted. The amount of added hydrogen was changed to 150°C when the temperature was 70°C. The results are shown in Table 2 together with the results of Example 1. The results show that when the first step was performed, an obvious increase in bulk density and stereoregularity was obtained compared to the case where the first step was omitted, and unexpectedly increased the amount of polymer formed per waiting unit cataly-large marked. This is an obvious effect of the first treatment step. ;Comparative Example 3 ;This example illustrates the first polymerization step carried out with a conventional titanium trichloride type catalyst. ;Polymerization ;An autoclave with a useful volume of 2 1 was filled with 1 1 of kerosene, ;6 mmol of diethyl aluminum chloride and 2.0 mmol of titanium trichloride (AA grade). Hydrogen (400 ml) was added and approx. 27 g of propylene was polymerized under propylene supply for 20 min. at 40°C and ;2 ;4 kg/cm . G. Then within 20 min. the temperature in the system was increased to 70°C and propylene was <:>continuously added and polymerized for 4 hours ;2 ;at 7.0 kg/cm . G. For comparison, the polymerization was carried out at 70°C for 4 hours and 40 minutes. without performing the first polymerization step. The results are shown in table 3. The results show that a weak effect in the first polymerization step was observed by an increase in bulk density and stereoregularity. However, the effect was far less than the effect on the added titanium tetrachloride type catalyst, and it appears that the effect of the first step is not significantly observed with the conventional catalyst. A comparison of Table 2 with Table 3 shows that the use of the two-step method exhibits a unique effect on the catalyst containing a titanium catalyst component. ;Example 5 ;This example illustrates the effect of the first polymerization step on the statistical copolymerization of propylene and ethylene in the presence of the catalyst shown in Table 1. ;Polymerization ;An autoclave with a useful volume of 2 1 was filled with 1 1 the kerosene, 1.8 mmol triethylaluminium, 0.42 mmol ethyl benzoate and 0.1 mmol, calculated as titanium atom, of catalyst component A obtained in example 1. Hydrogen (150 ml) was added, and approx. 15 g of propylene was polymerized under a flow of propylene at 40 oC and ;2 ;2 kg/cm . G for 10 min.. ;Then within 20 min. the temperature in the system was increased to 60°C and propylene gas containing 5.7 mol% ethylene was added continuously and polymerized for 2 hours at 5 kg/cm 2.G. In comparison, propylene gas containing 5.9 mol% ethylene was fed continuously and polymerized at 60°C for 2.5 hours without performing the first polymerization step at 40°C. ;The results are shown in Table 4. ;;The results show that the ratio of the soluble polymer to the powdered copolymer was smaller/and the bulk density of the polymer is higher when the first step is performed than when the first step is omitted. The effect was greater than in ;. the case of homopolymerization. ;Example 6 ;Preparation of catalyst component A ;Commercially available anhydrous magnesium chloride (0.1 mol) was slurried in 0.3 1 of kerosene and 0.4 mol of ethanol and 0.1 mol of ethyl benzoate was added to the suspension at room temperature. Then 0.3 mol of diethylaluminum chloride was added at room temperature, and the mixture was stirred for 1 hour. The phase portion of the product was collected, washed sufficiently with kerosene, suspended in 0.3 l of a kerosene solution containing 30 ml of titanium tetrachloride and reacted at 80°C for 2 hours. After the reaction, the supernatant liquid was removed by decantation, and the solid portion was washed thoroughly with fresh kerosene. The resulting solid contained, on an atomic basis, 42.3 mg of titanium, 582 mg of chlorine and 132 mg of ethyl benzoate. ;Polymerization ;An autoclave with a useful volume of 2 1 was filled with 1.0 1 of kerosene, 1.6 mmol of triethylaluminum and 0.5 mmol of ethyl benzoate and 0.07 mmol, calculated as titanium atoms, of the catalyst component A prepared above. Hydrogen (250 ml) was added and approx. 35 g of propylene were polymerized under propylene supply at 40°C and 4 kg/cm 2 . G for 10 min.. ;Then within 20 min. the temperature of the polymerization system raised to 60°C and propylene was continuously fed and polymerized for 2 hours at 7.0 kg/cm 2. G. ;For comparison, the above polymerization was carried out in one step at 60°C for 25 hours without the first polymerization step at 40 °C. The results are shown in table 5. ;;Example 7 ;Preparation of catalyst component A ;10 g of catalyst component obtained by the catalyst preparation method in example 1 was suspended in 150 ml of kerosene and, while stirring, 3.4 mmol of triethylaluminium, 13.6 mmol of ethyl benzoate and 3.4 mmol of titanium tetrachloride were successively added at 1 hour intervals. After the reaction, the solid portion of the product was collected by filtration, washed thoroughly with purified n-hexane and dried to give a catalyst component A containing as atoms, 2.2 wt% titanium, 60.0 wt% chlorine and 10.8 wt% ethyl benzoate. ;Polymerization ;The polymerization in example 6 was repeated except that 2.0 mmol of triethylaluminium, 1.8 mmol of ethyl benzoate and 0.20 mmol calculated as titanium atoms of catalyst component A were added. For comparison, the above polymerization was carried out in the same manner as in Example 6 with the exception that the first step was omitted and the polymerization time was changed to 2.5 hours. ;The results are shown in Table 6. ;;Example 8 ;Preparation of catalyst component A ;Commercially available anhydrous magnesium chloride (20 g), 5.3 g of n-butyl benzoate and 2.3 g of p-cresol were filled into a stainless steel-( SUS 32) ball mill with an internal diameter of ;100 mm and an internal volume of 0.8 1 and which contained 2.8 kg of stainless steel (SUS 3 2) balls with a diameter of 15 mm in a nitrogen atmosphere and copulverized for 24 hours at an imposed acceleration of 7G. The resulting copulverized product (10 g) was slurried in 100 ml of titanium tetrachloride and after raising the temperature of the suspension to 100°C, it was stirred for 2 hours. The solid was then collected by hot filtration, washed with kerosene and hexane, and dried to give a titanium-containing solid catalyst component containing 2.8 wt% titanium, 61 wt% chlorine and 20.0 wt% magnesium. ;Polymerization ;The inside of a 2 l autoclave was flushed with propylene and then it was filled with 750 ml of hexane which was completely purified of oxygen and moisture, 3.75 mmol of triisobutylaluminum, 1.25 mmol of ethyl-p-toluate and 38 mg of the solid catalyst component as prepared above. They were stirred for 5 min. at 35°C and approx. 10 g of propylene was polymerized in the first step. The polymerization system was then heated to 55°C during approx. 5 min., and a propylene gas containing 6.2 mol% ethylene was continuously supplied and polymerized for 2.0 hours at 2.5 kg/cm 2 . G. The results are shown in Table 7. ;Example 9 ;Preparation of a catalyst component (A). A nitrogen purged bottle was filled with 50 ml of toluene and 12 ml of silicon tetrachloride and 50 ml of a normal butyl ether solution containing 0.05 mol of n-butyl magnesium chloride was added dropwise to the mixture at 10°C over 2 hours. After the addition, the temperature of the mixture was raised to 60°C and stirred at this temperature for 2 hours. The solid was collected by filtration, washed thoroughly with hexane and dried. The powdery solid was slurried in 50 ml of kerosene and 1.1 g of ethyl o-toluate and 0.8 g of ethyl cyclohexane-carboxylate were added. The mixture was stirred at 80°C for 2 hours. The supernatant was removed by decantation and decantation was further carried out using fresh solvent until washing was complete. Titanium tetrachloride (100 ml) was added to 30 ml of the suspension containing a solid. The mixture was heated to 110°C and then stirred for 2 hours. The supernatant was removed by decantation and 100 ml of titanium tetrachloride was further added. The mixture was stirred at 130°C for 2 hours, and the solid was collected by hot filtration. It was thoroughly washed with hot kerosene and hexane, and dried to give a catalyst component (A) containing, as atoms, 1.5 wt% titanium, 68.0 wt% chlorine and 22.0 wt% magnesium. ;Polymerization ;A propylene gas containing ethylene was polymerized under the same conditions as in Example 8 with the exception that tri-n-hexyl aluminum was used instead of triisobutylaluminum, ethyl p-anisate was used instead of ethyl p-toluate and 67 mg of the solid catalyst component prepared as above was used. The results are shown in table 7. ;Example 10 ;Preparation of a catalyst component ( A) ;A reactor was filled with 50 ml of a butyl ether solution containing 0.05 mol n-butyl magnesium chloride in a nitrogen atmosphere, and 0.05 mol 2 ,6-dimethylphenol was added dropwise. The mixture was heated to 70°C and stirred for 2 hours. The butyl ether was removed by decantation and 50 ml of purified kerosene was added. Furthermore, 0.01 mol of ethyl p-anisate was added dropwise. The mixture was heated to 80°C and stirred for 2 hours at this temperature. The solid portion was collected by filtration, washed with purified hexane and dried under reduced pressure. The resulting product was slurried in 100 ml of titanium tetrachloride and reacted with stirring for 2 hours at 100°C. The supernatant was removed by decantation and 100 ml of titanium tetrachloride was added. The mixture was stirred for 2 hours at 100°C, and the solid was collected by hot filtration. The solid portion was washed completely with purified hexane and dried under reduced pressure to give a titanium-containing solid catalyst component containing 2.9 wt% titanium, 59 wt% chlorine and 19 wt% magnesium. ;Polymerization ;A 2 l autoclave was filled with 750 ml of hexane purged of oxygen and moisture. While blowing through a propylene gas containing 7.39 mol% ethylene, 3.75 mmol of an organoaluminium-r compound with an average composition Et,, gAl(0Et),Q ^, 1.25 mmol of methyl p-toluate and 37 mg of the solid catalyst component prepared as above charged" The autoclave was sealed and 0.2N1 H2 was introduced. The contents were stirred at 35°C for 5 min. to polymerize 12 g of the propylene gas. Analysis showed that the polymer thus formed in the first step contained 2.1 mol% ethylene. The polymerization system was then heated to 60°C during approx. 7 min. A propylene gas containing 7.39 moles of ethylene was supplied continuously and polymerized for 2 hours at a total pressure of 2.5 kg/cm 2.G. The results are shown in Table 7, ;Example 11 ;Preparation of a catalyst component A ;Mg(0®)2 was synthesized by reacting commercially available MgfOCH^)., with phenol. A stainless steel ball mill cylinder with an internal capacity of 0.8 L and an internal diameter of 100 mm containing 2.8 kg of stainless steel (SUS 32) balls with a diameter of 15 mm was filled with 0.2 mol of Mg (0@>)2 and 0.033 mol of n-octyl benzoate in a nitrogen atmosphere and they were then copulverized for 24 hours with an imposed acceleration of 7G. The resulting solid product was slurried in 200 ml of titanium tetrachloride and the suspension was stirred at 100°C for 2 hours. The solid was then collected by hot filtration, washed thoroughly with hexane and dried to give a titanium-containing solid catalyst component containing 2.8 wt% titanium, 60.0 wt% chlorine and 21.0 wt% magnesium. ;Polymerization ;A propylene gas containing ethylene was polymerized under ;the same conditions as in Example 10 except that 37 mg of the titanium-containing catalyst component prepared as above was used, 3.75 mmol of an organoaluminum compound with an average composition Et2 yAlHQ ^ was used instead of the compound Et„ -Al(OEt) 1# and the amount of polymerized propylene gas in the first step was 15 g. The results are shown in Table 7. ;Example 12 ;Polymerization ;A 2 l's autoclave was filled with 3.75 mmol of diethyl aluminum chloride , 3.75 mmol of n-butylmagnesium chloride synthesized in kerosene, 1.25 mmol of methyl p-toluate and 37 mg of the titanium-containing solid catalyst component prepared in Example 11 in the order indicated in a propylene atmosphere. The autoclave was sealed and 0.2 Ni H 2 filled. By stirring the contents at 35°C for 5 min. 9 g of propylene gas was polymerized in the first step. The polymerization system was heated at 60°C for 5 min. A propylene gas containing 6.58 mol% ethylene was supplied continuously and polymerized at 60°C and 2.5 kg/cm<2>. G for 2 hours. The results are shown in table 7. ; Example 13: To demonstrate the use of an ether as an electron donor in the preparation of the catalyst component A, 20 g of commercially available magnesium chloride and 6.63 g of diisoamyl ether blue were ground in a ball mill under the conditions given in example 1. The ground product was treated with titanium tetrachloride as indicated in Example 1 to give the catalyst component (A). The catalyst component (A) contained on an atomic basis 2.1% by weight titanium, 69.0% by weight chlorine, 22% by weight magnesium and 5.9% by weight diisoamyl ether and had a specific surface area ;2 ;of 153 m /g. ;Polymerization: ;The polymerization was carried out under the conditions shown in example 1 and 615 g of white powdery propylene and 23 g of a soluble polymer were obtained. The powdered polypropylene had a boiling n-heptane extraction residue of 96.6%, a bulk density of 0.42 g/cm and [ r\ ] of 2.6 g/dl. ;Comparative Experiment: ;Polymerization was carried out using the catalyst component (A) obtained above under the conditions shown for Comparative Example 1. 430 g of polypropylene powder and 21.5 g of a soluble polymer were obtained. The polypropylene powder had a boiling n-heptane extraction residue of 92.7%, a bulk density of 0.36 g/cm and a [ r\] of 2.4 g/dl in *

Claims (2)

1. Process for the production of propylene polymers or copolymers by polymerization of propylene or copolymerization of propylene with up to 10 moles of ethylene at room temperature or a higher temperature under a pressure of 1 - 100 kg/cm 2 in the presence of a catalyst comprising (A) a solid titanium catalyst component, and (B) an organo-aluminum catalyst component, the polymerization or copolymerization being carried out in two stages, characterized in that the polymerization is carried out in (a) a first stage where at least 100 mmol per mmol titanium atom of propylene is polymerized or copolymerized with ethylene at a temperature of less than 50°C to form a polymer or copolymer whose amount is not more than 30% by weight based on the final product obtained in the second step, the titanium catalyst component ( A) is a solid titanium complex catalyst component consisting of magnesium, titanium, halogen and an electron donor which is an organic acid ester or an ether, and where the halogen/titanium molar ratio is at least 8, the magnesium/titanium molar ratio is-at least 3, the electron donor/titanium- the molar ratio is 0.2-6, and the specific surface area of the solid component is at least approx. 40 m 2 /g, and (b) a second step, where it is polymerized at a temperature which is higher than the temperature in the first step and which is within the range of 50 - 90°C. 2. Method according to claim 1, characterized in that a temperature is used in the second step which is at least 10°C higher than the temperature in the first step and lies within the range 60 - 80°C.