CA1126900A - Process for preparing a copolymer - Google Patents
Process for preparing a copolymerInfo
- Publication number
- CA1126900A CA1126900A CA337,704A CA337704A CA1126900A CA 1126900 A CA1126900 A CA 1126900A CA 337704 A CA337704 A CA 337704A CA 1126900 A CA1126900 A CA 1126900A
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- compound
- magnesium
- process according
- ethylene
- acid ester
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/16—Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
- Polymerisation Methods In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process is provided herein for preparing an ethylene-propylene copolymer having a melt index ranging from 0.01 to 10 and a density ranging from 0.910 to 0.945. In such process, ethylene and 6 to 100 mol% thereof of propylene are copolymerized in a substantially solvent-free vapor phase condition and in the presence of a catalyst consisting of a solid substance and an organoaluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and a titanium compound and/or a vanadium compound. The polymerization reaction can be performed in extremely high activity and extremely stably with reduced production of coarse or ultra-fine particles, with minimized adhesion to the reactor and conglomeration of polymer particles. The copolymerization can be performed at relatively low temperatures to provide medium or low density ethylene copolymers having a high melt index. The copolymer formed has superior transparency and elasticity and has a high resistance to impact and environ-mental stress cracking. Thus, it can be formed into films, sheets, hollow containers, insulation for electric wires by the known methods of extrusion molding, blow molding, injection molding, press forming and vacuum forming.
The films have the properties of excellent transparency, anti-blocking properties, heat sealing properties and flexibility. Because of its large elongation, extremely thin films may be formed. Because its crystallinity is high and its heat resistance is good, it forms an unsticky film of high transparency, useful for packing and agricultural uses.
A process is provided herein for preparing an ethylene-propylene copolymer having a melt index ranging from 0.01 to 10 and a density ranging from 0.910 to 0.945. In such process, ethylene and 6 to 100 mol% thereof of propylene are copolymerized in a substantially solvent-free vapor phase condition and in the presence of a catalyst consisting of a solid substance and an organoaluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and a titanium compound and/or a vanadium compound. The polymerization reaction can be performed in extremely high activity and extremely stably with reduced production of coarse or ultra-fine particles, with minimized adhesion to the reactor and conglomeration of polymer particles. The copolymerization can be performed at relatively low temperatures to provide medium or low density ethylene copolymers having a high melt index. The copolymer formed has superior transparency and elasticity and has a high resistance to impact and environ-mental stress cracking. Thus, it can be formed into films, sheets, hollow containers, insulation for electric wires by the known methods of extrusion molding, blow molding, injection molding, press forming and vacuum forming.
The films have the properties of excellent transparency, anti-blocking properties, heat sealing properties and flexibility. Because of its large elongation, extremely thin films may be formed. Because its crystallinity is high and its heat resistance is good, it forms an unsticky film of high transparency, useful for packing and agricultural uses.
Description
~LZ69~) This invention relates to a new process for preparing a medium or low density ethylene copolymer by a vapor phase polymerization using a Ziegler catalyst of high activity.
Polyethylenes prepared by polymerization using a catalyst con-sisting of a transition metal compound and an organometallic compound are generally prepared by the slurry polymerization process, and the poly-ethylenes usually produced are only those having a density not lower than 0.945. Such value is considered to be the limit in order to prevent poly-mer deposition or fouling on the inner wall or stirrer in the interior of a reactor at the time of polymeri~ation.
Medium or low density polyethylenes having a density below 0.945 g/cm3 are usually prepared by the so-called high pressure process u.sing a radical catalyst. Quite recently, however, a high-temperature sollltion polymerizatLon process using a Ziegler catalyst has also been tried.
Low density polyethylenes prepared by the high pressure process are advantageous in that they are superior in transparency and flexibility to high density polyethylenes. At the same time, however, they are dis-advantageous in that the melting point is low and films formed therefrom are low in stiffness.
Also, polyethylenes prcparcd by the higll-tclnpcrat~re solutLon polymerization process hnve a poor trnnHp.lrency and fLimls for[ned therefrom give a sticky impression.
Regarding the production method, the high pressure process requires a very lligh pressure, thus causing the investment in production facilities to become incrcased, and also requires high power consumption and other operation costs. The hlgh-temperature solution polymerization process is also disadvantageous in that the resulting polyethylene must be handled as a solution, thus requiring operation at a relatively low concen-tration, resulting in the productivity becoming inferior and the production .
~269~)0 of polyethylenes of a high grade in molecular weight becoming virtually impossible. Furthermore, the polymers prepared according to the high-temperature solution polymerization process contain a large amount of wax because of a high temperature polymerization, so that it is necessary to provide means for the separation thereof. In the solution polymerization at a high temperature, moreover, side reactions, e.g., the hydrogenation and dimerization of ethylene, briskly occur, thus requiring an increased unit of ethylene and that of hydrogen.
In the production of polyolefins, copolymerizing ethylene with other monomer has heretofore been known as one method of lowering the density of polyethylene. However, if a medium or low density polyethylene is to be prepared by the copolymerization of ethylene and other comonomer according to a known method, the other comonomer is usually required in a large exccss amount, and this fact itself is very disadvantageous when viewed from the standpoint of the process. The copolymeriæation according to the slurry polymerization process involves additional disadvantages, i.e., the by-production of a low grade polymer or a solvent~soluble polymer, and the polymerization product takes in solvent and becomes milky or mushy, which Dot only makes the reactor operation and slurry transport difficult, but also results in the separation of solvent from the polymer being no longer easy. Furthermore, adl)esLon of copolymcr to the reactor inside occurs due to Lts foullrlg~ and the result-Lng deterioration ln heat transfer characteriE,tic causcs the polymerization temperature to become uncontrollable.
In recent years it has been found that if a transition metal is attaclled to a magnesium-containing solid carrier, e.g., MgO, Mg(OH)2, MgC12, MgC03 and Mg(OH)Cl, and then combined with an organometa]lic com-pound, the resulting catalyst system can serve as a catalyst of extremely high activity in olefin polymerization. It is also known that the reaction product of an organomagnesium compound, e.g. RMgX, R~Mg and RMg(OR), and a ~z~
transition metal compound, can serve as a high activity catalyst for olefin polymerization (see, for example, Japanese Patent Publication No.
12105/64, Belgian Patent No. 742,112, Japanese Patent Publications Nos.
13050/68 and 9548/70).
However, even if such high activity catalysts with carrier are used in the slurry polymerization or the high-temperature solution poly-merization with a view to preparing medium or low density polyethylenes, the foregoing drawbacks heretofore have not been completely eliminated.
The present invention has been devised after comprehensive studies concerning the foregoing technical problems were carried out.
According, therefore, to a broad aspect of this invention, it has been found that a vapor phase polymerization reaction can be carried out in an cxtremely stable manner and the catalyst removing step can be eliminated, so it is possible to provide a vapor phase polymerization process for ethylene which process as whole is very simple. Surprisingly, moreover, it has been found that the process of aspects of this invention can very easily provide a medium or low density ethylene polymer which has excellent trans-parency and melts higher and is stronger than conventional low density poly-ethylenes prepared according to the high pressure process.
In more particular terms, by a broad nspect of thl~ Lnvention, a process has been provided for preparlng an ethylenc-propylene copolymer having a melt index ranging from 0.01 to 10 and a derlsity ranging from 0.910 to 0.945, which comprises contacting a mixture of ethylene and 6 to 100 mol% thereof of propylene, in the vapor phase condition, with a cata-lyst consistlng of a solid substance and an organoaluminum compound, the solid substance containlng a magnesium-containing inorganic solid compound and at least one of a titanium compou[ld and a vanadium conpound, whereby ethylene and propylene are allowed to copolymerize.
By one variant, the at least one of a titanium compound and vanadium compound is a halide, alkoxyhalide, oxide or halogenated oxide of 9~
at least one of titanium and vanadium.
By another variant, the at least one of a titanium compound and vanadium compound is used as the addition product with an organocar-boxylic acid ester.
By yet another variant, the magnesium-containing inorganic solid compound is selected from the group consisting of metallic magnesium) magnesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride.
By still another variant, the magnesium-containing inorganic solid compound is selected from the group consisting of double salts, double oxides, carbonates, chlorides and hydroxides containing a magnesium atom and a metal selected from the group consisting of silicon, aluminum und calcium.
By a still furtller variant, the magnesium-containing inorganic solid compound is further treated or reacted with an oxygen-containing compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing substance.
By a still further variant, the magnesium-containing inorganic solid compound is contacted with an organocarboxylic acid ester before use.
By yet another variant, the organoalunlLnum conlpolmd is used as the addition product with an orKanocarboxyllc acid ester.
By yet a further variant, the catalyst is prepared in the presence of an organocarboxylic acid ester.
By another variant, the organocarboxylic acid ester is selected from the group consisting of alkylestérs of benzoic acid, anisic acid and toluic acid.
By a further variant, the polymerization is carried out at a temperature in the range of from 20 to 110C. and at a pressure in the range of from atmospheric to 70 kg/cm G.
By yet a further variant, the copolymerization is carried out in ~Z69~
the presence of hydrogen.
By another variant, before initiating the copolymerization, the catalyst system is contacted with an o~-olefin having 3 to 12 carbon atoms for 1 minute to 24 hours at a temperature in the range of from 0 to 200C.
and at a pressure in the range of from -1 to 100 kg/cm2-G.
It has now become clear that if a vapor phase polymerization reaction is carried out according to the process of aspects of this inven-tion using ethylene and propylene in a quantitative ratio within the range specified herein and also using a catalyst consisting of a solid substance and an organoaluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and at least one of a titanium compound and a vanadium compound, such polymerization can be perfonned in extremely high activity and extremely stably with reduced production of coarse or ultra-fine particles and improved particle properties, and also with minimized adhesion to the reactor and conglomeration of polymer partic]es.
It is therefore quite unexpected and surprislng that, according to the process of aspects of this invention, not only can a vapor phase polymeriza-tion reaction be carried out extremely smoothly, but also medium or low density ethylene copolymers can be obtained easily.
The copo1~ymerization reaction of aspects of tlrls invention can be performed at a relatlvely low telnpcrat-lre caHI,Iy to prcpare medium or low density ethylene copolymers, so that the adhesion to reactor or con-glomeration of product is not significantly observed. I'his point is another advantage of aspects of this invention.
The process of aspects of this invention also enables the easy obtaining of a medium or low density ethylene copolymer having a high melt index. '~lis is a further advantage of aspects of this invention.
Thanks to these advantages, the copolymer as set forth herein can be obtained efficiently by vapor phase polymerization.
l'he propylene polymerized with ethylene in the process of aspects 31~2~
of this invention adjusts the density and molecular weight of the resul-ting copolymer,and the copolymer obtained is superior in transparency and elasticity. It also exhibits a very high resistance to impact and to environmental stress cracking. Consequently, the copolymer produced according to the process of aspects of this invention can be Eormed into films, sheets, hollow containers, insulation for electric wires and various other products by means of known methods, e.g., extrusion molding, blow molding, injection molding, press forming and vacuum forming, and thus can be used in various applications. Particularly in the field of films, the copolymer produced according to the process of aspects of this invention exhibits its features because of excellent transparency, anti-blocking property, heat sealing property and flexibility. That is, it is possible to attain an equal or even superior transparency to that of a high pressure process film, and the strength which is a specially important physical property required of a film is much higher than that of a high pressure process polyethylene. Besides, a large elongation permits forming of an extremely thin film.
Although the density of the copolymer produced according to the process of aspects of this invention is medium or low, the crystallinity is relatively high and the heat resistance is good, providing nn unsticky film of high transparency, for whicll re~son the copolymer In qucst-Lon is especially suitable for use as a film for packing or agriculatural use. It is also suited to blow molding because of high transyarency, stiffness and resistance to environmental stress cracking.
The catalyst system used in the process of aspects of this invention consists of the combination of a .solid substance and an organo-aluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and at least one of a titanium compound and a vanadium compound. The solid substance just referred to above is obtained by attaching at least one of a titanium compound and a vanadium compound 9~0 to an inorganic solid carrier typical of which are metallic magnesium, magnesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride; double salts, double oxides, carbonates, chlorides and hydrox-ides containing a metal selected from silicon, aluminum and calcium, and magnesium atoms; further, these inorganic solid carriers treated or reacted with an oxygen-containing compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing substance.
As the titanium compound and the vanadium compound referred to herein, halides, alkoxyhalides, oxides and halogenated oxides of titanium and vanadium may be used. Examples are tetravelent titanium compounds, e.g., titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monoethoxytrichlorotitanium, diethoxydichlorotitanium, triethoxymonochloro-titanlum, tetraethoxytitanium, monolsopropoxytrichlorotitanium, diisoprop-oxydlchlorotLtanlum and tetraisopropoxytltanium; various titanium tri-halides obtained by reducing titanium tetrahalides with hydrogen, aluminum, titanium or an organometallic compound; tetravalent vanadium compounds, e.g., vanadium tetrachloride; pentavalent vanadium compounds, e.g., vana-dium oxytrichloride and orthoalkylvanadate; and trivalent vanadium com-pounds, e.g., vanadium trichloride and vanadium triethoxide.
Among the above-exemplified titanlum compolmds and vanadium com-pounds, tetravalent titanium compounds are JpecLally preL~rred.
The catalyst used ln the process of aspects of thls invention consists of the comblnatlon of a solld substance, whlch is obtained by attaching at least one of a titanium compound and a vanadium compound to the foregoing solid carrier, and to an organoaluminum compound.
By way o illustrating preferred catalyst systems, mentlon may be made of the following solid substances (tlle R ln the followlng formulae represents an organlc radical and X represents halogen~ combined with an organoaluminum compounds: MgO-RX-TlCl~ system (see Japanese Patent Publi-cation No. 3514/76), Mg-SIC14-TiC14 system (see Japanese Patent Publication ~ ~3LZ~9~
No. 2386~/75), MgC12-Al(OR)3=TiCl4 system (see Japanese Patent Publication Nos. 152/76 and 15111/77), M~cl2-sicl4-RoH-Ticl4 syste (see Japanese Patent Laying ~pen Print No. 106581~74), Mg(OOCR)2-Al(OR)3-TiC14 system (see Japanese Patent Publication ho. 11710/77), Mg-POC13-TiC14 system (see Japanese Patent Publication ~o. 153/76), MgC12-AlOCl-TiC14 system (see Japanese Patent Laying Open llrint No. 133386/76).
In these catalyst ~ystems, at least one of a titanium compound and a vanadium compound may be used as ~he addition product with an organocarboxylic acid ester. The foregoing magnesium-containing inorganic compound carriers may be con~acted with an organocarboxylic acid ester before use. Also, an organo~luminum compound may be used as the additlon product with an organocarbox~lic acid ester, which would cause no trouble.
Furthermore, in every case in the process of aspects of this invention, a catalyst system which has l)een prepared in the presence of an organo-carboxylic acid ester may be used without trouble.
Various aliphatic, alicyclic and aromatic carboxylic acid esters may be used as organocarboxylic acid esters, among which aromatic carboxylic ~ -acids having 7 to 12 carbon ~toms are specially preferred. Examples are alkylesters, e.g., methyl and ethyl of ben~oic acid, anisic acid and toluic acid.
To illustrate organoaluminum compounds which may be used in the catalyst used in the process of aspects of this invention, mention may be made of those represented by the general formulae R3Al, R2AlX, RAlX2, R2Al~R, RAl(OR)X and R3A12X3 wherein R, which may be the same or different, is Cl to C20 alkyl or aryl a~d X is halogen, for example, triethylaluminum, triisobutylaluminum, trihexylaluminum9 trioctylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, and mixtures thereof.
The amount of an olganoaluminum compound used in the catalyst system used in the process o~ aspects of this invention is not specially - 30 restricted, but usually it is in the range of from 0.1 to 1000 mols per '~
mol of a transition metal compound.
In the polymerization reaction, a mixture of ethylene and propy-lene is polymerized in the vapor phase in a reactor, which may be a known type, e.g., a fluidized bed or an agitation vessel.
The polymerization reaction conditions involve temperatures usually in the range of from 20 to 110C., preferably from 50" to 100C., and pressures in the range of from atmospheric pressure to 70 kg/cm G, preferably from 2 to 60 kg/cm2-G. The molecular weight can be adjusted by changing the polymerization temperature, the molar ratio of catalyst or the amount of comonomer, but the addition of hydrogen into the polymeriæa-tion system is more effective for this purpose. Of course, using the process of aspects of this invention, two or more stage polymerization reactions involving differcnt polymerization conditions, e.g., different hydrogen and comonomer concentrations and different polymerization tem-peratures may be carried out, without trouble.
In the process of aspects of this invention, moreover, the fore-going catalyst systems may be contacted with an o<-olefin before their use in vapor phase polymerization reaction whereby their polymerization activities can be largely improved and a more stable operation is assured than in untreated condition. In this case, vnrious c~-oleEins are employ-able, preferably those huvLng 3 to 12 carbon atoms and more prefer.qbly those having 3 to 8 carbon atoms, for exarnple, propylene, butene-l, pentene-l, 4-methylpentene-1, hexene-l, heptene-l, octene-l, and mixtures thereof. The temperature and time of the contact between the catalyst used in the process of aspects of this invention and an o~ -olefin can be selected in a wide range, for example, the contact treatment may be applied for 1 minute to 24 hours at a temperature ranging from 0 to 200C., pre-ferably from 0 to 110C.
The amount of an ~-olefin to be brought into contact can also be selected in a wide range, but usually it is desired that the contact ~269~
treatment in question be conducted with an ~-olefin in an amount ranging from 1 g to 50,000 g~ preferably from 5 g to 30,000 g, per gram of the aforesaid solid substance and that 1 g to 500 g of the ~<-olefin be reacted with the solid substance. The contact pressure may be selected optionally, but usually it is desired to be in the range of from -1 to 100 kg/cm2 G.
In the treatment with an C<-olefin, the total amount of an organoaluminum compound to be used may be combined with the foregoing solid substance and thereafter the resulting mixture may be contacted with the ~-olefin, or part of the organoaluminum compound may be combined with the solid substance and thereafter the resulting mixture may be contacted with the ~-olefin, while the remaining portion of the organoaluminum com-po~ d may be .L;cparatcly added in the simultaneous presence of hydrogen gas or other inert gas, e.g., nitrogen, argon or helium, the catalyst used in the process of aspects of this invention may be brought into contact with an '~ -olefin without causing troub]e.
The amount of propylene should be in the range of from 6 to 100 mol%, preferably from 6 to 60 mol% based on the amount of ethylene. Out-side this range, it is virtually impossible to obtain the object product from the process of aspects of this invention, nalllely an ctlly1cllc-propylene copolymer having a melt Lndcx rangLng Erom 0.01 to 10 ~nd a density ranging from 0.910 to 0.945. The amount of propylene to be used can be easily adjusted according to the composition ratio of the vapor phase in the polymerization vessel.
In the copolymerization according to the process of aspects of this invention, moreover, various dLenes may be added as termonomers, e.g., butadiene, l,4-hexadiene, 1,5-hexadiene, vinylnorbornene, ethylidenenor-borene and dicyclopentadiene.
Working examples of aspects of this invention are given below, but it is to be understood that these examples are for illustration only for working aspects o~ this invention.
Example l l kg of anhydrous magnesium chloride, 50 g of 1,2-dichloroethane and 170 g of titanium tetrachloride were subjected to ball milling for 16 hours at room temperature in a nitrogen atmosphere to allow the titanium compound to be attached to the carrier. The resulting solid substance con~
tained 35 mg of titanium per gram thereof.
There were used a stainless steel autoclave as a vapor phase polymerization apparatus, a blower, a flow ratio adjuster and a dry cyclone lC to form a loop, and the temperature of the autoclave was adjusted by passing warm water through the jacket.
Into the autoclave adjusted to 80C. were introduced the solid substarlce prepared above and triethylaluminum at the rates of 250 mg/hr and 50 mmol/l-r, respectively, and also introduced were propylene, ethylene and hydrogen so that the propylene/ethylene ratio (molar ratio) was 0.35 and the hydrogen gas pressure was 10% of the total pressure, whlle the gases in the system were circulated by the blower, under which conditions there was conducted polymerization. The resulting ethylene copolymer had a bulk density of 0.380, a melt index (ML) of 1.6 and a density of 0.928. It was powdered with most particle sizes falling under the r~nge of 250 to 500 ~.
The polymerizatLon activity wns vcry h:lgll, 209,300 g copolymcr/g Ti.
After a corltirluous operation for 10 hours, the autoclave was opened and its interior was checked to find that the inner wall and the stirrer were clean with no polymer adhesion observed. ~lus, it is apparent that an extremely stab]e operation is made possible according to the pro-cess of aspects of this invention, though it is impossible according to the slurry polymerization shown in Comparative Example 1 below.
The copolymer prepared above was formed into a film 400 mm in fold diamter by 30~l thick by an inflation film forming 75 mm~ die in a 3~ 50 nun~ extruder. ~le film was superior in strength and had a high trans-~12690~
parency with a haze value of 5.8% measured according to JIS K6714.
Comparative Example 1 A continuous slurry polymerization was carried out at 85DC. using the same catalyst as that used ;n Example 1 and in the presence of hexane as solvent.
Hexane as a polymerization solvent containing 5 mg!~ of the solid substance and 1 mmol/~ of triethylaluminum was fed at the rate of 40 ,e /hr, and further introduced were ethylene, propylene (80 mol% of ethylene) and hydrogen at the rates of 8 kg/hr, 9.6 kg/hr and 3Nm /hr, respectively, while a continuous polymerization was conducted on condition that the residence time was 1 hour. The resulting copolymer was continu-ously withdrawn as slurry. In 2 hours after initiation of the polymeriza-tion, the polymer slurry withdrawing pipe was obturated, so the polymeriza-tion was compelled to be discontinued.
A check was made for the in.erior of the reactor to find that the hexane layer was emulsified and a large amolmt of a rubbery polymer adhered to the gas-liquid interface and to the withdrawing pipe.
The copolymer prepared above had a bulk density of 0.253, MI of 1.4 and a density of 0.930.
Example 2 _._ 830 g of nnhydrolls magneELum chlorldc, 50 g of alllmLnllm oxy-chlorlde and 170 g of titanium were subjected to ball milling for 16 hours at room temperature in a nitrogen atmosphere. The resultLng solid substance contained 41 mg of titanium per gram thereof.
The so]id substance just prepared above and triethylaluminum were fed at tlle rates of 200 mg/hr and 50 mmol/llr, respectively, and the same polymerization as in Example 1 was carried out at 80C. with the proviso that the propylene/ethylene ratio in the vapor phase was 0.20 and the hydrogen gas pressure was 14% of the total pressure.
After 10 hours of continuous operation, the interior of the 1~269~Q
autoclave was checked, but there was no polymer adhesion.
The resulting copolymer had a bulk density of 0.406, MI of 1.
and a density of 0.938. The polymerization activity was very high, 300,500 g ethylene copolymer/g Ti.
In the same manner as in Example 1, the copolymer was forme~
into a film 400 mm in fold diameter by 30 ~ thick, which was superior in transparency and in strength.
Comparative Example 2 A solution polymerization was carried out using the sc~me catalyst as that used in Example 2 and in the presence of j-paraffin as solvent.
n-Paraffin containing 25 mg/~ of the solid substance prepared in Example 2 and 5 mmol/~ of triethylaluminum was fed at the rate of 40 ~ /hr, and further introduced were ethylene, propylene (117 mol% of ethylene) and hydrogen at the rates of 8 kg/hr, 14 kg/hr and O.lNm3/hr, respectively, and a continuous polymerization was carried out at 160C.
on condition that the residence time was 1 hour.
The resulting ethylene had MI of 1.5 and a density of 0.931, and the polymeri~tion activity was 97,000 g copolymer/g Ti. Thus, it is apparent that in such a solution polymerization, despite a large excess of propylene used with respect to ethylene, the denstty was not lowcrcd so much, and the polymerizatiorl actlvlty ~nd ciriclcllcy wcre low.
Example 3 830 g of anhydrous magnesiu~ chloride, 120 g o~ anthracene and 170 g of titanium tetrachloride were subjected to ball milling in the same manner ~s in Rxample 1 to give a solid substance which contained 40 mg of titanlum per gram thereof.
Using the same apparatus as that used in Example 1, the solid substance and triisobutylaluminum were fed at 80C. at the rates of 500 mg/hr and 150 mmol/hr, respectivcly, and a polymerization was conducted while making ad~ustment so that the propylene/ethylene ratio in the vapor 1~2~9Qo phase was 0.82 and the hydrogen gas pressure was 15% of the total pressure.
The polymerization was continued stably for 10 hours; then the autoclave was opened to find that there was no polymer adhesion inside ~he reactor.
The polymerization activity was 187,000 g copolymer/g Ti, and the resulting polymer had a bulk density of 0.375, MI of 4.4 and a density of 0.915.
The ethylene polymer thus prepared was formed into an inflation film 400 mm in fold diameter by 30~ thick in the same manner as in Example 1. The film was superior in strength and in transparency with a haze value of 4.9% measured according to JIS K6714.
Example 4 400 g oE magnesium oxide and 1300 g of anhydrous aluminum chloride were reacted together at 300C. for 4 hours, then 950 g of the reaction product and 170 g of titanium tetrachloride were treated in the same way as in Example 1 to give a solid substance which contained 39 mg of titanium per gram thereof.
Using the same apparatus as that used in Example 1, the solid substance just prepared above and triethylaluminum were fed as catalyst at the rates of 500 mg/hr and 250 mmol/hr, reflpectively, and a polymeriza-tion was conducted at 70C. while circuLating a mLxed ethylene-propylene gas containing 72~ of propylene based on the amount of ethylene and also hydrogen gas adjusted to 10% of the total pressure.
After 18 hours of continuous operation, the interior of the rcactor was checked to flnd that there was no polymer adhesion.
The res~llting copolymer was composed of oval particles with a narrow particle size distribution, having an average particle diameter of 800 ~ , a bulk density of 0.36~, MI of 0.60 and a density of 0.920, and the polymerization activity was 223,000 g copolymer/g Ti.
The copolymer, without pelletizing, was formed into a hollow 1~269~C~
bottle having a capacity of 600 cc by means of a high-speed blow molding machine. The bottle had a clean surface without draw-down.
Polyethylenes prepared by polymerization using a catalyst con-sisting of a transition metal compound and an organometallic compound are generally prepared by the slurry polymerization process, and the poly-ethylenes usually produced are only those having a density not lower than 0.945. Such value is considered to be the limit in order to prevent poly-mer deposition or fouling on the inner wall or stirrer in the interior of a reactor at the time of polymeri~ation.
Medium or low density polyethylenes having a density below 0.945 g/cm3 are usually prepared by the so-called high pressure process u.sing a radical catalyst. Quite recently, however, a high-temperature sollltion polymerizatLon process using a Ziegler catalyst has also been tried.
Low density polyethylenes prepared by the high pressure process are advantageous in that they are superior in transparency and flexibility to high density polyethylenes. At the same time, however, they are dis-advantageous in that the melting point is low and films formed therefrom are low in stiffness.
Also, polyethylenes prcparcd by the higll-tclnpcrat~re solutLon polymerization process hnve a poor trnnHp.lrency and fLimls for[ned therefrom give a sticky impression.
Regarding the production method, the high pressure process requires a very lligh pressure, thus causing the investment in production facilities to become incrcased, and also requires high power consumption and other operation costs. The hlgh-temperature solution polymerization process is also disadvantageous in that the resulting polyethylene must be handled as a solution, thus requiring operation at a relatively low concen-tration, resulting in the productivity becoming inferior and the production .
~269~)0 of polyethylenes of a high grade in molecular weight becoming virtually impossible. Furthermore, the polymers prepared according to the high-temperature solution polymerization process contain a large amount of wax because of a high temperature polymerization, so that it is necessary to provide means for the separation thereof. In the solution polymerization at a high temperature, moreover, side reactions, e.g., the hydrogenation and dimerization of ethylene, briskly occur, thus requiring an increased unit of ethylene and that of hydrogen.
In the production of polyolefins, copolymerizing ethylene with other monomer has heretofore been known as one method of lowering the density of polyethylene. However, if a medium or low density polyethylene is to be prepared by the copolymerization of ethylene and other comonomer according to a known method, the other comonomer is usually required in a large exccss amount, and this fact itself is very disadvantageous when viewed from the standpoint of the process. The copolymeriæation according to the slurry polymerization process involves additional disadvantages, i.e., the by-production of a low grade polymer or a solvent~soluble polymer, and the polymerization product takes in solvent and becomes milky or mushy, which Dot only makes the reactor operation and slurry transport difficult, but also results in the separation of solvent from the polymer being no longer easy. Furthermore, adl)esLon of copolymcr to the reactor inside occurs due to Lts foullrlg~ and the result-Lng deterioration ln heat transfer characteriE,tic causcs the polymerization temperature to become uncontrollable.
In recent years it has been found that if a transition metal is attaclled to a magnesium-containing solid carrier, e.g., MgO, Mg(OH)2, MgC12, MgC03 and Mg(OH)Cl, and then combined with an organometa]lic com-pound, the resulting catalyst system can serve as a catalyst of extremely high activity in olefin polymerization. It is also known that the reaction product of an organomagnesium compound, e.g. RMgX, R~Mg and RMg(OR), and a ~z~
transition metal compound, can serve as a high activity catalyst for olefin polymerization (see, for example, Japanese Patent Publication No.
12105/64, Belgian Patent No. 742,112, Japanese Patent Publications Nos.
13050/68 and 9548/70).
However, even if such high activity catalysts with carrier are used in the slurry polymerization or the high-temperature solution poly-merization with a view to preparing medium or low density polyethylenes, the foregoing drawbacks heretofore have not been completely eliminated.
The present invention has been devised after comprehensive studies concerning the foregoing technical problems were carried out.
According, therefore, to a broad aspect of this invention, it has been found that a vapor phase polymerization reaction can be carried out in an cxtremely stable manner and the catalyst removing step can be eliminated, so it is possible to provide a vapor phase polymerization process for ethylene which process as whole is very simple. Surprisingly, moreover, it has been found that the process of aspects of this invention can very easily provide a medium or low density ethylene polymer which has excellent trans-parency and melts higher and is stronger than conventional low density poly-ethylenes prepared according to the high pressure process.
In more particular terms, by a broad nspect of thl~ Lnvention, a process has been provided for preparlng an ethylenc-propylene copolymer having a melt index ranging from 0.01 to 10 and a derlsity ranging from 0.910 to 0.945, which comprises contacting a mixture of ethylene and 6 to 100 mol% thereof of propylene, in the vapor phase condition, with a cata-lyst consistlng of a solid substance and an organoaluminum compound, the solid substance containlng a magnesium-containing inorganic solid compound and at least one of a titanium compou[ld and a vanadium conpound, whereby ethylene and propylene are allowed to copolymerize.
By one variant, the at least one of a titanium compound and vanadium compound is a halide, alkoxyhalide, oxide or halogenated oxide of 9~
at least one of titanium and vanadium.
By another variant, the at least one of a titanium compound and vanadium compound is used as the addition product with an organocar-boxylic acid ester.
By yet another variant, the magnesium-containing inorganic solid compound is selected from the group consisting of metallic magnesium) magnesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride.
By still another variant, the magnesium-containing inorganic solid compound is selected from the group consisting of double salts, double oxides, carbonates, chlorides and hydroxides containing a magnesium atom and a metal selected from the group consisting of silicon, aluminum und calcium.
By a still furtller variant, the magnesium-containing inorganic solid compound is further treated or reacted with an oxygen-containing compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing substance.
By a still further variant, the magnesium-containing inorganic solid compound is contacted with an organocarboxylic acid ester before use.
By yet another variant, the organoalunlLnum conlpolmd is used as the addition product with an orKanocarboxyllc acid ester.
By yet a further variant, the catalyst is prepared in the presence of an organocarboxylic acid ester.
By another variant, the organocarboxylic acid ester is selected from the group consisting of alkylestérs of benzoic acid, anisic acid and toluic acid.
By a further variant, the polymerization is carried out at a temperature in the range of from 20 to 110C. and at a pressure in the range of from atmospheric to 70 kg/cm G.
By yet a further variant, the copolymerization is carried out in ~Z69~
the presence of hydrogen.
By another variant, before initiating the copolymerization, the catalyst system is contacted with an o~-olefin having 3 to 12 carbon atoms for 1 minute to 24 hours at a temperature in the range of from 0 to 200C.
and at a pressure in the range of from -1 to 100 kg/cm2-G.
It has now become clear that if a vapor phase polymerization reaction is carried out according to the process of aspects of this inven-tion using ethylene and propylene in a quantitative ratio within the range specified herein and also using a catalyst consisting of a solid substance and an organoaluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and at least one of a titanium compound and a vanadium compound, such polymerization can be perfonned in extremely high activity and extremely stably with reduced production of coarse or ultra-fine particles and improved particle properties, and also with minimized adhesion to the reactor and conglomeration of polymer partic]es.
It is therefore quite unexpected and surprislng that, according to the process of aspects of this invention, not only can a vapor phase polymeriza-tion reaction be carried out extremely smoothly, but also medium or low density ethylene copolymers can be obtained easily.
The copo1~ymerization reaction of aspects of tlrls invention can be performed at a relatlvely low telnpcrat-lre caHI,Iy to prcpare medium or low density ethylene copolymers, so that the adhesion to reactor or con-glomeration of product is not significantly observed. I'his point is another advantage of aspects of this invention.
The process of aspects of this invention also enables the easy obtaining of a medium or low density ethylene copolymer having a high melt index. '~lis is a further advantage of aspects of this invention.
Thanks to these advantages, the copolymer as set forth herein can be obtained efficiently by vapor phase polymerization.
l'he propylene polymerized with ethylene in the process of aspects 31~2~
of this invention adjusts the density and molecular weight of the resul-ting copolymer,and the copolymer obtained is superior in transparency and elasticity. It also exhibits a very high resistance to impact and to environmental stress cracking. Consequently, the copolymer produced according to the process of aspects of this invention can be Eormed into films, sheets, hollow containers, insulation for electric wires and various other products by means of known methods, e.g., extrusion molding, blow molding, injection molding, press forming and vacuum forming, and thus can be used in various applications. Particularly in the field of films, the copolymer produced according to the process of aspects of this invention exhibits its features because of excellent transparency, anti-blocking property, heat sealing property and flexibility. That is, it is possible to attain an equal or even superior transparency to that of a high pressure process film, and the strength which is a specially important physical property required of a film is much higher than that of a high pressure process polyethylene. Besides, a large elongation permits forming of an extremely thin film.
Although the density of the copolymer produced according to the process of aspects of this invention is medium or low, the crystallinity is relatively high and the heat resistance is good, providing nn unsticky film of high transparency, for whicll re~son the copolymer In qucst-Lon is especially suitable for use as a film for packing or agriculatural use. It is also suited to blow molding because of high transyarency, stiffness and resistance to environmental stress cracking.
The catalyst system used in the process of aspects of this invention consists of the combination of a .solid substance and an organo-aluminum compound, the solid substance containing a magnesium-containing inorganic solid compound and at least one of a titanium compound and a vanadium compound. The solid substance just referred to above is obtained by attaching at least one of a titanium compound and a vanadium compound 9~0 to an inorganic solid carrier typical of which are metallic magnesium, magnesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride; double salts, double oxides, carbonates, chlorides and hydrox-ides containing a metal selected from silicon, aluminum and calcium, and magnesium atoms; further, these inorganic solid carriers treated or reacted with an oxygen-containing compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing substance.
As the titanium compound and the vanadium compound referred to herein, halides, alkoxyhalides, oxides and halogenated oxides of titanium and vanadium may be used. Examples are tetravelent titanium compounds, e.g., titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monoethoxytrichlorotitanium, diethoxydichlorotitanium, triethoxymonochloro-titanlum, tetraethoxytitanium, monolsopropoxytrichlorotitanium, diisoprop-oxydlchlorotLtanlum and tetraisopropoxytltanium; various titanium tri-halides obtained by reducing titanium tetrahalides with hydrogen, aluminum, titanium or an organometallic compound; tetravalent vanadium compounds, e.g., vanadium tetrachloride; pentavalent vanadium compounds, e.g., vana-dium oxytrichloride and orthoalkylvanadate; and trivalent vanadium com-pounds, e.g., vanadium trichloride and vanadium triethoxide.
Among the above-exemplified titanlum compolmds and vanadium com-pounds, tetravalent titanium compounds are JpecLally preL~rred.
The catalyst used ln the process of aspects of thls invention consists of the comblnatlon of a solld substance, whlch is obtained by attaching at least one of a titanium compound and a vanadium compound to the foregoing solid carrier, and to an organoaluminum compound.
By way o illustrating preferred catalyst systems, mentlon may be made of the following solid substances (tlle R ln the followlng formulae represents an organlc radical and X represents halogen~ combined with an organoaluminum compounds: MgO-RX-TlCl~ system (see Japanese Patent Publi-cation No. 3514/76), Mg-SIC14-TiC14 system (see Japanese Patent Publication ~ ~3LZ~9~
No. 2386~/75), MgC12-Al(OR)3=TiCl4 system (see Japanese Patent Publication Nos. 152/76 and 15111/77), M~cl2-sicl4-RoH-Ticl4 syste (see Japanese Patent Laying ~pen Print No. 106581~74), Mg(OOCR)2-Al(OR)3-TiC14 system (see Japanese Patent Publication ho. 11710/77), Mg-POC13-TiC14 system (see Japanese Patent Publication ~o. 153/76), MgC12-AlOCl-TiC14 system (see Japanese Patent Laying Open llrint No. 133386/76).
In these catalyst ~ystems, at least one of a titanium compound and a vanadium compound may be used as ~he addition product with an organocarboxylic acid ester. The foregoing magnesium-containing inorganic compound carriers may be con~acted with an organocarboxylic acid ester before use. Also, an organo~luminum compound may be used as the additlon product with an organocarbox~lic acid ester, which would cause no trouble.
Furthermore, in every case in the process of aspects of this invention, a catalyst system which has l)een prepared in the presence of an organo-carboxylic acid ester may be used without trouble.
Various aliphatic, alicyclic and aromatic carboxylic acid esters may be used as organocarboxylic acid esters, among which aromatic carboxylic ~ -acids having 7 to 12 carbon ~toms are specially preferred. Examples are alkylesters, e.g., methyl and ethyl of ben~oic acid, anisic acid and toluic acid.
To illustrate organoaluminum compounds which may be used in the catalyst used in the process of aspects of this invention, mention may be made of those represented by the general formulae R3Al, R2AlX, RAlX2, R2Al~R, RAl(OR)X and R3A12X3 wherein R, which may be the same or different, is Cl to C20 alkyl or aryl a~d X is halogen, for example, triethylaluminum, triisobutylaluminum, trihexylaluminum9 trioctylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, and mixtures thereof.
The amount of an olganoaluminum compound used in the catalyst system used in the process o~ aspects of this invention is not specially - 30 restricted, but usually it is in the range of from 0.1 to 1000 mols per '~
mol of a transition metal compound.
In the polymerization reaction, a mixture of ethylene and propy-lene is polymerized in the vapor phase in a reactor, which may be a known type, e.g., a fluidized bed or an agitation vessel.
The polymerization reaction conditions involve temperatures usually in the range of from 20 to 110C., preferably from 50" to 100C., and pressures in the range of from atmospheric pressure to 70 kg/cm G, preferably from 2 to 60 kg/cm2-G. The molecular weight can be adjusted by changing the polymerization temperature, the molar ratio of catalyst or the amount of comonomer, but the addition of hydrogen into the polymeriæa-tion system is more effective for this purpose. Of course, using the process of aspects of this invention, two or more stage polymerization reactions involving differcnt polymerization conditions, e.g., different hydrogen and comonomer concentrations and different polymerization tem-peratures may be carried out, without trouble.
In the process of aspects of this invention, moreover, the fore-going catalyst systems may be contacted with an o<-olefin before their use in vapor phase polymerization reaction whereby their polymerization activities can be largely improved and a more stable operation is assured than in untreated condition. In this case, vnrious c~-oleEins are employ-able, preferably those huvLng 3 to 12 carbon atoms and more prefer.qbly those having 3 to 8 carbon atoms, for exarnple, propylene, butene-l, pentene-l, 4-methylpentene-1, hexene-l, heptene-l, octene-l, and mixtures thereof. The temperature and time of the contact between the catalyst used in the process of aspects of this invention and an o~ -olefin can be selected in a wide range, for example, the contact treatment may be applied for 1 minute to 24 hours at a temperature ranging from 0 to 200C., pre-ferably from 0 to 110C.
The amount of an ~-olefin to be brought into contact can also be selected in a wide range, but usually it is desired that the contact ~269~
treatment in question be conducted with an ~-olefin in an amount ranging from 1 g to 50,000 g~ preferably from 5 g to 30,000 g, per gram of the aforesaid solid substance and that 1 g to 500 g of the ~<-olefin be reacted with the solid substance. The contact pressure may be selected optionally, but usually it is desired to be in the range of from -1 to 100 kg/cm2 G.
In the treatment with an C<-olefin, the total amount of an organoaluminum compound to be used may be combined with the foregoing solid substance and thereafter the resulting mixture may be contacted with the ~-olefin, or part of the organoaluminum compound may be combined with the solid substance and thereafter the resulting mixture may be contacted with the ~-olefin, while the remaining portion of the organoaluminum com-po~ d may be .L;cparatcly added in the simultaneous presence of hydrogen gas or other inert gas, e.g., nitrogen, argon or helium, the catalyst used in the process of aspects of this invention may be brought into contact with an '~ -olefin without causing troub]e.
The amount of propylene should be in the range of from 6 to 100 mol%, preferably from 6 to 60 mol% based on the amount of ethylene. Out-side this range, it is virtually impossible to obtain the object product from the process of aspects of this invention, nalllely an ctlly1cllc-propylene copolymer having a melt Lndcx rangLng Erom 0.01 to 10 ~nd a density ranging from 0.910 to 0.945. The amount of propylene to be used can be easily adjusted according to the composition ratio of the vapor phase in the polymerization vessel.
In the copolymerization according to the process of aspects of this invention, moreover, various dLenes may be added as termonomers, e.g., butadiene, l,4-hexadiene, 1,5-hexadiene, vinylnorbornene, ethylidenenor-borene and dicyclopentadiene.
Working examples of aspects of this invention are given below, but it is to be understood that these examples are for illustration only for working aspects o~ this invention.
Example l l kg of anhydrous magnesium chloride, 50 g of 1,2-dichloroethane and 170 g of titanium tetrachloride were subjected to ball milling for 16 hours at room temperature in a nitrogen atmosphere to allow the titanium compound to be attached to the carrier. The resulting solid substance con~
tained 35 mg of titanium per gram thereof.
There were used a stainless steel autoclave as a vapor phase polymerization apparatus, a blower, a flow ratio adjuster and a dry cyclone lC to form a loop, and the temperature of the autoclave was adjusted by passing warm water through the jacket.
Into the autoclave adjusted to 80C. were introduced the solid substarlce prepared above and triethylaluminum at the rates of 250 mg/hr and 50 mmol/l-r, respectively, and also introduced were propylene, ethylene and hydrogen so that the propylene/ethylene ratio (molar ratio) was 0.35 and the hydrogen gas pressure was 10% of the total pressure, whlle the gases in the system were circulated by the blower, under which conditions there was conducted polymerization. The resulting ethylene copolymer had a bulk density of 0.380, a melt index (ML) of 1.6 and a density of 0.928. It was powdered with most particle sizes falling under the r~nge of 250 to 500 ~.
The polymerizatLon activity wns vcry h:lgll, 209,300 g copolymcr/g Ti.
After a corltirluous operation for 10 hours, the autoclave was opened and its interior was checked to find that the inner wall and the stirrer were clean with no polymer adhesion observed. ~lus, it is apparent that an extremely stab]e operation is made possible according to the pro-cess of aspects of this invention, though it is impossible according to the slurry polymerization shown in Comparative Example 1 below.
The copolymer prepared above was formed into a film 400 mm in fold diamter by 30~l thick by an inflation film forming 75 mm~ die in a 3~ 50 nun~ extruder. ~le film was superior in strength and had a high trans-~12690~
parency with a haze value of 5.8% measured according to JIS K6714.
Comparative Example 1 A continuous slurry polymerization was carried out at 85DC. using the same catalyst as that used ;n Example 1 and in the presence of hexane as solvent.
Hexane as a polymerization solvent containing 5 mg!~ of the solid substance and 1 mmol/~ of triethylaluminum was fed at the rate of 40 ,e /hr, and further introduced were ethylene, propylene (80 mol% of ethylene) and hydrogen at the rates of 8 kg/hr, 9.6 kg/hr and 3Nm /hr, respectively, while a continuous polymerization was conducted on condition that the residence time was 1 hour. The resulting copolymer was continu-ously withdrawn as slurry. In 2 hours after initiation of the polymeriza-tion, the polymer slurry withdrawing pipe was obturated, so the polymeriza-tion was compelled to be discontinued.
A check was made for the in.erior of the reactor to find that the hexane layer was emulsified and a large amolmt of a rubbery polymer adhered to the gas-liquid interface and to the withdrawing pipe.
The copolymer prepared above had a bulk density of 0.253, MI of 1.4 and a density of 0.930.
Example 2 _._ 830 g of nnhydrolls magneELum chlorldc, 50 g of alllmLnllm oxy-chlorlde and 170 g of titanium were subjected to ball milling for 16 hours at room temperature in a nitrogen atmosphere. The resultLng solid substance contained 41 mg of titanium per gram thereof.
The so]id substance just prepared above and triethylaluminum were fed at tlle rates of 200 mg/hr and 50 mmol/llr, respectively, and the same polymerization as in Example 1 was carried out at 80C. with the proviso that the propylene/ethylene ratio in the vapor phase was 0.20 and the hydrogen gas pressure was 14% of the total pressure.
After 10 hours of continuous operation, the interior of the 1~269~Q
autoclave was checked, but there was no polymer adhesion.
The resulting copolymer had a bulk density of 0.406, MI of 1.
and a density of 0.938. The polymerization activity was very high, 300,500 g ethylene copolymer/g Ti.
In the same manner as in Example 1, the copolymer was forme~
into a film 400 mm in fold diameter by 30 ~ thick, which was superior in transparency and in strength.
Comparative Example 2 A solution polymerization was carried out using the sc~me catalyst as that used in Example 2 and in the presence of j-paraffin as solvent.
n-Paraffin containing 25 mg/~ of the solid substance prepared in Example 2 and 5 mmol/~ of triethylaluminum was fed at the rate of 40 ~ /hr, and further introduced were ethylene, propylene (117 mol% of ethylene) and hydrogen at the rates of 8 kg/hr, 14 kg/hr and O.lNm3/hr, respectively, and a continuous polymerization was carried out at 160C.
on condition that the residence time was 1 hour.
The resulting ethylene had MI of 1.5 and a density of 0.931, and the polymeri~tion activity was 97,000 g copolymer/g Ti. Thus, it is apparent that in such a solution polymerization, despite a large excess of propylene used with respect to ethylene, the denstty was not lowcrcd so much, and the polymerizatiorl actlvlty ~nd ciriclcllcy wcre low.
Example 3 830 g of anhydrous magnesiu~ chloride, 120 g o~ anthracene and 170 g of titanium tetrachloride were subjected to ball milling in the same manner ~s in Rxample 1 to give a solid substance which contained 40 mg of titanlum per gram thereof.
Using the same apparatus as that used in Example 1, the solid substance and triisobutylaluminum were fed at 80C. at the rates of 500 mg/hr and 150 mmol/hr, respectivcly, and a polymerization was conducted while making ad~ustment so that the propylene/ethylene ratio in the vapor 1~2~9Qo phase was 0.82 and the hydrogen gas pressure was 15% of the total pressure.
The polymerization was continued stably for 10 hours; then the autoclave was opened to find that there was no polymer adhesion inside ~he reactor.
The polymerization activity was 187,000 g copolymer/g Ti, and the resulting polymer had a bulk density of 0.375, MI of 4.4 and a density of 0.915.
The ethylene polymer thus prepared was formed into an inflation film 400 mm in fold diameter by 30~ thick in the same manner as in Example 1. The film was superior in strength and in transparency with a haze value of 4.9% measured according to JIS K6714.
Example 4 400 g oE magnesium oxide and 1300 g of anhydrous aluminum chloride were reacted together at 300C. for 4 hours, then 950 g of the reaction product and 170 g of titanium tetrachloride were treated in the same way as in Example 1 to give a solid substance which contained 39 mg of titanium per gram thereof.
Using the same apparatus as that used in Example 1, the solid substance just prepared above and triethylaluminum were fed as catalyst at the rates of 500 mg/hr and 250 mmol/hr, reflpectively, and a polymeriza-tion was conducted at 70C. while circuLating a mLxed ethylene-propylene gas containing 72~ of propylene based on the amount of ethylene and also hydrogen gas adjusted to 10% of the total pressure.
After 18 hours of continuous operation, the interior of the rcactor was checked to flnd that there was no polymer adhesion.
The res~llting copolymer was composed of oval particles with a narrow particle size distribution, having an average particle diameter of 800 ~ , a bulk density of 0.36~, MI of 0.60 and a density of 0.920, and the polymerization activity was 223,000 g copolymer/g Ti.
The copolymer, without pelletizing, was formed into a hollow 1~269~C~
bottle having a capacity of 600 cc by means of a high-speed blow molding machine. The bottle had a clean surface without draw-down.
Claims (14)
1. A process for preparing an ethylene-propylene copolymer having a melt index ranging from 0.01 to 10 and a density ranging from 0.910 to 0.945, which comprises: copolymerizing ethylene and 6 to 100 mol% thereof of propylene in a substantially solvent-free vapor phase condition and in the presence of a catalyst consisting of a solid substance and an organo-aluminum compound, said solid substance containing a magnesium-containing inorganic solid compound and at least one of a titanium compound and a vanadium compound.
2. A process according to claim 1, in which said at least one of a titanium compound and vanadium compound is a halide, alkoxyhalide, oxide or halogenated oxide of at least one of titanium and vanadium.
3. A process according to claim 1, in which said at least one of a titanium compound and vanadium compound is used as the addition product with an organocarboxylic acid ester.
4. A process according to claim 1, in which said magnesium-containing inorganic solid compound is selected from the group consisting of metallic magnesium, magnesium hydroxide, magnesium carbonate, magnesium oxide and magnesium chloride.
5. A process according to claim 1, In which said magnesium-containing inorganic solid compound is selected from the group consisting of double salts, double oxides, carbonates, chlorides and hydroxides con-taining a magnesium atom and a metal selected from the group consisting of silicon, aluminum and calcium.
6. A process according to claim 1, in which said magnesium-containing inorganic solid compound is further treated or reacted with an oxygen-containing compound, a sulfur-containing compound, a hydrocarbon or a halogen-containing substance.
7. A process according to claim 1, in which said magnesium-containing inorganic solid compound is contacted with an organocarboxylic acid ester before use.
8. A process according to claim 1, in which said organoaluminum compound is used as the addition product with an organocarboxylic acid ester.
9. A process according to claim 1, in which said catalyst is prepared in the presence of an organocarboxylic acid ester.
10. A process according to claims 6 or 7 in which said organo-carboxylic acid ester is selected from the group consisting of alkylesters of benzoic acid, anisic acid and toluic acid.
11. A process according to claims 8 or 9 in which said organo-carboxylic acid ester is selected from the group consisting of alkylesters of benzoic acid, anisic acid and toluic acid.
12. A process according to claim 1, in which said copolymerization is carried out at a temperature in the range of from 20° to 110°C. and at a pressure in the range of from atmospheric to 70 kg/cm2.G.
13. A process according to claim 1, in which said copolymerization is carried out in the presence of hydrogen.
14. A process according to claim 1, in which, before initiating the copolymerization, the catalyst system is contacted with an .alpha.-olefin having 3 to 12 carbon atoms for 1 minute to 24 hours at a temperature in the range of from 0° to 200°C. and at a pressure in the range of from -1 to 100 kg/cm2.G.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP126867/1978 | 1978-10-17 | ||
| JP12686778A JPS5554308A (en) | 1978-10-17 | 1978-10-17 | Preparation of copolymer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1126900A true CA1126900A (en) | 1982-06-29 |
Family
ID=14945789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA337,704A Expired CA1126900A (en) | 1978-10-17 | 1979-10-16 | Process for preparing a copolymer |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5554308A (en) |
| CA (1) | CA1126900A (en) |
| DE (1) | DE2942014A1 (en) |
| FR (1) | FR2439210B1 (en) |
| GB (1) | GB2033911B (en) |
| IT (1) | IT1125488B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS603324B2 (en) * | 1978-12-28 | 1985-01-28 | 三井化学株式会社 | Method for producing ethylene copolymer |
| JPS6042806B2 (en) * | 1979-12-26 | 1985-09-25 | 日石三菱株式会社 | Copolymer manufacturing method |
| JPS56145607A (en) * | 1980-04-11 | 1981-11-12 | Nippon Oil Co Ltd | Wire or cable protection coating layer |
| JPS56155226A (en) * | 1980-05-02 | 1981-12-01 | Nippon Oil Co Ltd | Manufacture of radiation-bridged polyolefin |
| JPS5734105A (en) * | 1980-08-08 | 1982-02-24 | Nippon Petrochem Co Ltd | Stretched film |
| JPS5738837A (en) * | 1980-08-19 | 1982-03-03 | Mitsubishi Chem Ind Ltd | Production of polyolefin film |
| JPS5790006A (en) * | 1980-11-27 | 1982-06-04 | Nippon Petrochem Co Ltd | Agricultural film |
| JPS57102909A (en) * | 1980-12-17 | 1982-06-26 | Nippon Petrochem Co Ltd | Polyolefin lid |
| EP0099774B2 (en) * | 1982-06-24 | 1995-03-22 | BP Chimie Société Anonyme | Process for the polymerization and copolymerization of alpha-olefins in a fluidized bed |
| JPS6072908A (en) * | 1983-09-30 | 1985-04-25 | Yotsukaichi Polymer:Kk | Production of ethylene copolymer |
| US5256351A (en) * | 1985-06-17 | 1993-10-26 | Viskase Corporation | Process for making biaxially stretched, heat shrinkable VLDPE films |
| CA1340037C (en) * | 1985-06-17 | 1998-09-08 | Stanley Lustig | Puncture resistant, heat-shrinkable films containing very low density polyethylene copolymer |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AR206852A1 (en) * | 1975-03-10 | 1976-08-23 | Union Carbide Corp | PROCEDURE FOR PREPARING LOW AND MEDIUM DENSITY ETHYLENE POLYMERS IN A FLUID BED REACTOR |
| JPS51133386A (en) * | 1975-05-15 | 1976-11-19 | Nippon Oil Co Ltd | A process for manufacturing a polyolefin |
| FR2312511A1 (en) * | 1975-05-27 | 1976-12-24 | Naphtachimie Sa | DRY POLYMERIZATION OF OLEFINS IN SERIAL REACTORS |
| ZA791363B (en) * | 1978-03-31 | 1980-03-26 | Union Carbide Corp | Preparation of ethylene copolymers in fluid bed reactor |
-
1978
- 1978-10-17 JP JP12686778A patent/JPS5554308A/en active Granted
-
1979
- 1979-10-16 GB GB7935829A patent/GB2033911B/en not_active Expired
- 1979-10-16 CA CA337,704A patent/CA1126900A/en not_active Expired
- 1979-10-17 FR FR7925826A patent/FR2439210B1/en not_active Expired
- 1979-10-17 DE DE19792942014 patent/DE2942014A1/en not_active Withdrawn
- 1979-10-17 IT IT26561/79A patent/IT1125488B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| FR2439210B1 (en) | 1986-03-21 |
| IT1125488B (en) | 1986-05-14 |
| DE2942014A1 (en) | 1980-05-08 |
| FR2439210A1 (en) | 1980-05-16 |
| JPS6320843B2 (en) | 1988-04-30 |
| GB2033911A (en) | 1980-05-29 |
| GB2033911B (en) | 1983-05-05 |
| JPS5554308A (en) | 1980-04-21 |
| IT7926561A0 (en) | 1979-10-17 |
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