CA1076300A - Process for producing polypropylene - Google Patents
Process for producing polypropyleneInfo
- Publication number
- CA1076300A CA1076300A CA269,718A CA269718A CA1076300A CA 1076300 A CA1076300 A CA 1076300A CA 269718 A CA269718 A CA 269718A CA 1076300 A CA1076300 A CA 1076300A
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- CA
- Canada
- Prior art keywords
- process according
- ether
- titanium trichloride
- ethyl
- titanium
- Prior art date
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
Abstract
PROCESS FOR PRODUCING POLYPROPYLENE
ABSTRACT OF THE DISCLOSURE
In a process for the polymerization of propylene, a polymer having improved mechanical properties can be obtained in high yields without forming a noticeable amount of an amor-phous polymer as a by-product by using a catalyst system comprising (a) a fine, granular form of titanium trichloride, (b) an organo-aluminum compound and (c) an organic carboxylate, the titanium trichloride being a finely granulated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium trichloride and an ether in the presence of a Lewis acid.
ABSTRACT OF THE DISCLOSURE
In a process for the polymerization of propylene, a polymer having improved mechanical properties can be obtained in high yields without forming a noticeable amount of an amor-phous polymer as a by-product by using a catalyst system comprising (a) a fine, granular form of titanium trichloride, (b) an organo-aluminum compound and (c) an organic carboxylate, the titanium trichloride being a finely granulated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium trichloride and an ether in the presence of a Lewis acid.
Description
~Cli763~
FIELD OF THE INVENTION:
This invention relates to a process for the polymeri-zation of propylene, and more particularly to a process for the manufacture of polypropylene having higher crystallinity and improved properties by using a unique catalyst sys~em having higher polymerization activity.
BACKGROUND OF THE INVENTION:
.
It is fundamental and well known in the production of polypropylene to use the so-called Ziegler-Natta catalysts con-sisting of titanium trichloride and an organoaluminum compound.In general, crystalline polymers produced by the above methods have cxcellent mechanical, thermal, and chemical properties and are very useful in practical applications. However, upon poly-merization, as crystalline polymer is produced, a noticeable amount of amorphous polymer is also formed as a by-product. The amorphous polymer is commercially valueless and a product formed of crystalline polymer contaminated with amorphous polymer shows decreased physical properties. Therefore, a complicated after-treatment is usually necessary to remo~e the amorphous polymer.
Thus, there is a great need in the production of polyolefins to obtain a highly crystalline polymer in high yields without for-ming a noticeable amount of amorphous polymer as a by-product. To this end, various improvements have been proposed in the produc-tion of titanium trichloride catalysts having higher activity.
The most common such improved catalyst is a titanium trichloride catalyst which is prepared by reducing titanium tetrachloride with metallic aluminum and mechanically dividing the reduced material in a ball mill or the like.
iL~763~
Catalyst systems which can increase the crystallinity of polyolefins are also known. In this case, a suitable third component i5 added to the above improved type of titanium trichloride catalyst and the organoaluminum compound. An example of the third component is a carboxylate.
Such a catalyst system used in the manufacture of polyolefins, however, has failed to increase the crystallinity (stereoregularity) to sufficient levels that the removal of amorphous polymer can be omitted. In addition the polymerization activity remains low or may even decrease.
SV~RY OF THE INVENTION:
The present invention relates to a process for the polymerization of propylene in the presence of a catalyst system comprising (a) titanium trichloride, (b) an organo-aluminum compound and (c) an organic carboxylates.
It has been found according to this invention that the yields of polypropylene having high stereoregularity can be improved if the titanium trichloride in the above catalyst system is a finely granulated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium trichloride and an ether in the presence of a Lewis acid.
Titanium trichloride used herein may be any fine-granular solid titanium trichloride which is prepared by preci-pitation from a homogeneous li~uid mixture or solution of titanium trichloride and an ether. This homogeneous liquid mixture or ~L~7Ç;3~1~
solution is referred to hereinafter as "the homogeneous liquid" or "the homogeneous liquid comprising titanium trichloride".
The precipitation is preferably carried out in the presence of a hydrocarbon solvent and preferably at a temperature in the range of from 20 - 150C.
The preparation of the above type of titanium trichloride will be described in detail hereinafter. First of all, for the preparation of a homogeneous liquid com~
prising titanium trichloride (TiC13); the following two methods are preferred.
,;.~ , .
~L~7~30~
(A) Titanium tetrachloride is used as a starting material, which is reduced with a particular organo-aluminum compound in the presence of an ether and, if desired, a suitable hydrocarbon solvent.
S (B) Solid titanium trichloride i~ used as a starting material, which is treated with an ether, if desired, in the presence of a suitable hydro~arbon solvent.
Method (A) will be explained. According to method (A), titanium tetrachloride used as a starting matexial is subjected to reduction with a particular organo-aluminum compound in the presence of an ether and, if desired, a suitable hydrocarbon solvent to obtain a homogeneous liquid comprising titanium trichloride ~TiC13).
Any suitable ether may be employed as the ether in method (A), provided it forms a homogeneous liquid with titanium trichloride. Preferred examples of the ether are selected from ethers which are soluble in a hydrocarbon solvent, for example, ethers having the formula:
:RlOR;~ .............. ( 1 ) wherein Rl and R2 may be the same of different and represent members selected from the group consisting of alkyl, aralkyl, alkenyl, aryl and alkaryl radicals. Specific examples of the ether include dialkyl ethers such as di-n-amyl ether, di-n-butyl ether, di-n-propyl ether, di-n-hexyl ether, di-n-heptyl eeher di-n-octyl ether, di-n-decyl ether, di-n-dodeoyl ether, ~ 3~
di-n-tridecyl ether, n-amyl-n-butyl ether, n-amyl isobutyl ether, n-amyl ethyl ether, n-butyl-n-propyl ether, n-butyl isoamyl ether, n~ethyl-n-hexyl ether, n-propyl-n-hexyl ether, n-butyl-n-octyl ether, n-hexyl-n-octyl ether, etc.; dialkenyl ethers such as bis(l-butenyl) ether, bis(l-octenyl) ether, bis(l-decenyl) ether, l-octenyl-9-decenyl e~her, etc.; diaralkyl ethers such as bis(benzyl) ether, etc.; dialXaryl ether such as bis(tolyl) ether, bis(xylyl) ether, ~is(ethyl phenyl) ether, tolyl xylyl ether, etc.; alkyl alkenyl ethers such as propyl-l-butenyl ether, n-octyl-l-decenyl ether, n-decyl-l-decenyl ether, etc.; alkyl aralkyl ethers such as n-octyl benzyl ether, n-decyl benzyl ether, etc.; alkyl aryl ethers or alkyl alkaryl ethers such as n-octyl phenyl ether, n-octyl tolyl ether, n-decyl tolyl ether, etc.; aralkyl alkenyl ethers such as l-octenyl benzyl ether, etc.; aryl alkenyl ethers or alkaryl ¦alkenyl ethers such as l-octenyl phenyl ether, l-octenyl tolyl ether, etc~; and aralkyl aryl ethers or aralkyl alkaryl ethers such as benzyl phenyl ether, benzyl tolyl ether, etc.
¦Among them most preferred are ethers of the formula (1) l wherein R and R2 represent a linear hydrocarbon radical such ¦as an alkyl and alkenyl radical having more than 3 carbon atoms.
The hydrocarbon solvent which is, if necessary, employed in method (A), is selected, mainly depending upon the type of ether employed. Specific examples of the hydrocarbon include to saturated aliphatic hydrocarbons such as n-pentane, 10'76300 n-hexane, n-heptane, n-octane, n-dodecane, liquid paraffin, etc.;
alicyclic hydrocarbons such as cyclohexane, methyl cyclohexane, etc.; and axomatic hydrocarbons such as benzene, toluene, xylene, 1,2,4-trimethyl benzene, ethyl benzene, etc. In a ¦certain case, the hydrocarbon may be selected from halohydro-¦carbons such as chlorobenzene, bromobenzene, ortho-, meta- and ¦para-dichlorobenzene, ortho, meta- and para-dibromobenzene~
ortho- and para-chlorotaluene, 2,4-dibromotoluene, para-bromoethyl ben~ene, l-chloronaphthalene, etc. The above-described hydrocarbons may be used in admixture, if preferred.
Particularly when an ether having the formula ~1) wherein at least one of Rl and R2 represents an alkyl or alkenyl radical having less than 5 carbon atoms is used, the hydrocarbon may preferably be an alicyclic hydrocarbon and, most preferably, an aromatic hydrocarbon. In the case of an ether having the formula (1) wherein Rl and R2 represent an alkyl or alkenyl radical having more than 6 carbon atoms, the hydrocarbon may preferably be a saturated aliphatic hydrocarbon.
A halohydrocarbon may preferably be selected when diethyl ether is used.
For the reduction to be effected in method (A)~
an organo-aluminum compound having the general formula:
AQRnX3 n ~ (2~
wherein R3 represents a hydrocarbon radical having 1 - 20 carbon atoms, n is a number of the value of 1 - 3, and X represents a halogen atom, and preferably R3 represents an alkyl radical 1~763~
having 1 - 10 carbon atoms is used~ Among these most preferred are ethyl aluminum sesquichloride, diethyl aluminum chloride, triethyl aluminum, tributyl aluminum, etc.
i The above-described organo-aluminum compound is used for the reduction of titanium tetrachloride so tha~ the molar ratio of titanium tetrachloride to the organo-aluminum compound may be 1 : (0.1 - 50), preferably 1 : (0.3 - 10), when represented in terms of the molar ratio of titanium to R3 constituting the organo-aluminum compound (a hydrocarbon radical~ preferably an alkyl radical). Further, the amount of ~he ether used is adjusted 50 that the molar ratio of the ether to titanium tetrachloride may be 1 : (0.05 - 5), preferably from 1 : (0.25 -
FIELD OF THE INVENTION:
This invention relates to a process for the polymeri-zation of propylene, and more particularly to a process for the manufacture of polypropylene having higher crystallinity and improved properties by using a unique catalyst sys~em having higher polymerization activity.
BACKGROUND OF THE INVENTION:
.
It is fundamental and well known in the production of polypropylene to use the so-called Ziegler-Natta catalysts con-sisting of titanium trichloride and an organoaluminum compound.In general, crystalline polymers produced by the above methods have cxcellent mechanical, thermal, and chemical properties and are very useful in practical applications. However, upon poly-merization, as crystalline polymer is produced, a noticeable amount of amorphous polymer is also formed as a by-product. The amorphous polymer is commercially valueless and a product formed of crystalline polymer contaminated with amorphous polymer shows decreased physical properties. Therefore, a complicated after-treatment is usually necessary to remo~e the amorphous polymer.
Thus, there is a great need in the production of polyolefins to obtain a highly crystalline polymer in high yields without for-ming a noticeable amount of amorphous polymer as a by-product. To this end, various improvements have been proposed in the produc-tion of titanium trichloride catalysts having higher activity.
The most common such improved catalyst is a titanium trichloride catalyst which is prepared by reducing titanium tetrachloride with metallic aluminum and mechanically dividing the reduced material in a ball mill or the like.
iL~763~
Catalyst systems which can increase the crystallinity of polyolefins are also known. In this case, a suitable third component i5 added to the above improved type of titanium trichloride catalyst and the organoaluminum compound. An example of the third component is a carboxylate.
Such a catalyst system used in the manufacture of polyolefins, however, has failed to increase the crystallinity (stereoregularity) to sufficient levels that the removal of amorphous polymer can be omitted. In addition the polymerization activity remains low or may even decrease.
SV~RY OF THE INVENTION:
The present invention relates to a process for the polymerization of propylene in the presence of a catalyst system comprising (a) titanium trichloride, (b) an organo-aluminum compound and (c) an organic carboxylates.
It has been found according to this invention that the yields of polypropylene having high stereoregularity can be improved if the titanium trichloride in the above catalyst system is a finely granulated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium trichloride and an ether in the presence of a Lewis acid.
Titanium trichloride used herein may be any fine-granular solid titanium trichloride which is prepared by preci-pitation from a homogeneous li~uid mixture or solution of titanium trichloride and an ether. This homogeneous liquid mixture or ~L~7Ç;3~1~
solution is referred to hereinafter as "the homogeneous liquid" or "the homogeneous liquid comprising titanium trichloride".
The precipitation is preferably carried out in the presence of a hydrocarbon solvent and preferably at a temperature in the range of from 20 - 150C.
The preparation of the above type of titanium trichloride will be described in detail hereinafter. First of all, for the preparation of a homogeneous liquid com~
prising titanium trichloride (TiC13); the following two methods are preferred.
,;.~ , .
~L~7~30~
(A) Titanium tetrachloride is used as a starting material, which is reduced with a particular organo-aluminum compound in the presence of an ether and, if desired, a suitable hydrocarbon solvent.
S (B) Solid titanium trichloride i~ used as a starting material, which is treated with an ether, if desired, in the presence of a suitable hydro~arbon solvent.
Method (A) will be explained. According to method (A), titanium tetrachloride used as a starting matexial is subjected to reduction with a particular organo-aluminum compound in the presence of an ether and, if desired, a suitable hydrocarbon solvent to obtain a homogeneous liquid comprising titanium trichloride ~TiC13).
Any suitable ether may be employed as the ether in method (A), provided it forms a homogeneous liquid with titanium trichloride. Preferred examples of the ether are selected from ethers which are soluble in a hydrocarbon solvent, for example, ethers having the formula:
:RlOR;~ .............. ( 1 ) wherein Rl and R2 may be the same of different and represent members selected from the group consisting of alkyl, aralkyl, alkenyl, aryl and alkaryl radicals. Specific examples of the ether include dialkyl ethers such as di-n-amyl ether, di-n-butyl ether, di-n-propyl ether, di-n-hexyl ether, di-n-heptyl eeher di-n-octyl ether, di-n-decyl ether, di-n-dodeoyl ether, ~ 3~
di-n-tridecyl ether, n-amyl-n-butyl ether, n-amyl isobutyl ether, n-amyl ethyl ether, n-butyl-n-propyl ether, n-butyl isoamyl ether, n~ethyl-n-hexyl ether, n-propyl-n-hexyl ether, n-butyl-n-octyl ether, n-hexyl-n-octyl ether, etc.; dialkenyl ethers such as bis(l-butenyl) ether, bis(l-octenyl) ether, bis(l-decenyl) ether, l-octenyl-9-decenyl e~her, etc.; diaralkyl ethers such as bis(benzyl) ether, etc.; dialXaryl ether such as bis(tolyl) ether, bis(xylyl) ether, ~is(ethyl phenyl) ether, tolyl xylyl ether, etc.; alkyl alkenyl ethers such as propyl-l-butenyl ether, n-octyl-l-decenyl ether, n-decyl-l-decenyl ether, etc.; alkyl aralkyl ethers such as n-octyl benzyl ether, n-decyl benzyl ether, etc.; alkyl aryl ethers or alkyl alkaryl ethers such as n-octyl phenyl ether, n-octyl tolyl ether, n-decyl tolyl ether, etc.; aralkyl alkenyl ethers such as l-octenyl benzyl ether, etc.; aryl alkenyl ethers or alkaryl ¦alkenyl ethers such as l-octenyl phenyl ether, l-octenyl tolyl ether, etc~; and aralkyl aryl ethers or aralkyl alkaryl ethers such as benzyl phenyl ether, benzyl tolyl ether, etc.
¦Among them most preferred are ethers of the formula (1) l wherein R and R2 represent a linear hydrocarbon radical such ¦as an alkyl and alkenyl radical having more than 3 carbon atoms.
The hydrocarbon solvent which is, if necessary, employed in method (A), is selected, mainly depending upon the type of ether employed. Specific examples of the hydrocarbon include to saturated aliphatic hydrocarbons such as n-pentane, 10'76300 n-hexane, n-heptane, n-octane, n-dodecane, liquid paraffin, etc.;
alicyclic hydrocarbons such as cyclohexane, methyl cyclohexane, etc.; and axomatic hydrocarbons such as benzene, toluene, xylene, 1,2,4-trimethyl benzene, ethyl benzene, etc. In a ¦certain case, the hydrocarbon may be selected from halohydro-¦carbons such as chlorobenzene, bromobenzene, ortho-, meta- and ¦para-dichlorobenzene, ortho, meta- and para-dibromobenzene~
ortho- and para-chlorotaluene, 2,4-dibromotoluene, para-bromoethyl ben~ene, l-chloronaphthalene, etc. The above-described hydrocarbons may be used in admixture, if preferred.
Particularly when an ether having the formula ~1) wherein at least one of Rl and R2 represents an alkyl or alkenyl radical having less than 5 carbon atoms is used, the hydrocarbon may preferably be an alicyclic hydrocarbon and, most preferably, an aromatic hydrocarbon. In the case of an ether having the formula (1) wherein Rl and R2 represent an alkyl or alkenyl radical having more than 6 carbon atoms, the hydrocarbon may preferably be a saturated aliphatic hydrocarbon.
A halohydrocarbon may preferably be selected when diethyl ether is used.
For the reduction to be effected in method (A)~
an organo-aluminum compound having the general formula:
AQRnX3 n ~ (2~
wherein R3 represents a hydrocarbon radical having 1 - 20 carbon atoms, n is a number of the value of 1 - 3, and X represents a halogen atom, and preferably R3 represents an alkyl radical 1~763~
having 1 - 10 carbon atoms is used~ Among these most preferred are ethyl aluminum sesquichloride, diethyl aluminum chloride, triethyl aluminum, tributyl aluminum, etc.
i The above-described organo-aluminum compound is used for the reduction of titanium tetrachloride so tha~ the molar ratio of titanium tetrachloride to the organo-aluminum compound may be 1 : (0.1 - 50), preferably 1 : (0.3 - 10), when represented in terms of the molar ratio of titanium to R3 constituting the organo-aluminum compound (a hydrocarbon radical~ preferably an alkyl radical). Further, the amount of ~he ether used is adjusted 50 that the molar ratio of the ether to titanium tetrachloride may be 1 : (0.05 - 5), preferably from 1 : (0.25 -
2.5).
The reduction may be effected by any of the following different procedures.
(a) An organo-aluminum compound is added to a homogeneous liquid consisting of titanium tetrachloride and an ether, or vice versa.
(b) A homogeneous liquid consisting of an organo-aluminum compound and an ether is added to titanium tetrachloride, or vice versa.
~c) A homogeneous liquid consisting of an organo-aluminum compound and an ether is added to a homogeneous liquid consisting of titanium tetrachloride and an ether, or vice versa.
(d) Titanium tetrachloride~ an ether and an organo-aluminum compound are mixed with each other in any suitable sequence at a temperature a-t which reduction cannot occur~ for example, at a temperature below -30C and the mixture is then heated to a given reduction temperature~
Titanium tetrachloride, an ether and an organo-aluminum compound may be used either in the form of pure reagents or in the form o reagents diluted wi~h an apropriate solvent in the above procedures. It is particularly desired to dilute the organo-aluminum compound with a hydrocarbon solvent.
The reduction temperature is selected from within the range of -30 - 50C, preferably 10 - 40C.
The reduction of titanium tetrachloride with the organo-aluminum compound in the presence of the ether according to any of the above-described procedures results in a homogeneous li~uid which is a homogeneous solution or mixture comprising o titanium trichloride and the ether, besides organo-aluminum compound and unreacted titanium tetrachloride etc. in a certain case. This solution is soluble in the hydrocarbon solvent and is brown or greenish brown.
It is also preferable that iodine or an iodide is coexistent with the ether during the reduction of titanium tetrachloride in the above-described method (A). In this case, iodine or an iodide may preferably be added before the reduction of titanium tetrachloride is effected~ It is also possible to add iodine or iodide after the reduction is com-menced, so far as the reduction has not substantially been completed.
Method (B) will now be described. In this method, solid titanium trichloride used as a star-ting material is ¦ treated with an ether, if desired, in the presence of an appropriate hydrocarbon solvent to form a homogeneous liquid I comprising titanium trichloride. As the solid titanium trichlo-¦ ride, use may be made of, for example, a solid form of titanium trichloride prepared by reducing titenium tetraahloride with 107~300 hydrogen gas, aluminum or an organo-aluminum compound, a powder form of titanium trichloride prepar~d by fi~ely grinding the above-prepared solid titanium trichloride, or another foxm prepared by heating the above-prepared soli~ titanium trichloride. A purified produc~ of the above solid titanium trichloride which is obtained by removing the impurities thererom may also be used.
Examples of the ether and the hydrocarbon solvent used for obtaining a homogeneous liquid containing the above-described titanium trichloride include the same compounds as those mentioned with reference to method (A).
The ether is used in a suitable amount in method (B) so that the mola~ ratio of the ether to titanium trichloride may be above 1/1, preferably (1-5)/1, most pxeferably (1-2)/1.
~5 The treatment of solid titanium trichloride with the ether may be carried out in any desired manner, preferably by mixing them at a temperature of -30 - 120C, preferably 10 -50C. Such a treatment is usually carried out in the presence of a hydrocarbon solvent which is selected depending upon the ether used as described with reference to method (A).
It is to be noted that ethers of the formula (1) wherein Rl and R2 represent an alkyl radical having more than 6 carbon atoms are preferably used in method (B).
A homogeneous liquid formed according to method (B) is the same as that formed according to method (A), so far l as the same reagents are used.
As apparent from the above, either method (A) or (B) can advantageously provide a homogeneous liquid containing titanium trichloride.
In a subsequent step, fine-granular titanium trichloride having a high catalytic activity to olefin polymerization i5 precipitated in the presence of a Lewis acid from the above-prepared homogeneous liquid comprising titanium trichloride. The precipitation is not limited to any particular method, but can be performed according to any of widely varying methods. For example the above-prepared homogeneous liquid as such or, if desired, after added with the above-mentioned hydrocarbon diluent, is heated in th~ presence of a Lewis acid to a temperature of usually from 20 ~ 150C, preferably from 40 - 120C, most pre-fexably from 60 - 100C to induce the precipitation, and then lS maintained at the same temperature for a certain period of time to ensure the precipitation until completion.
In this case, in order to facilitate the precipitation, the amount of aforementioned hydrocarbon solvent is prefexred to be not less than twice by weight of the ether.
In a certain case where the total mole number of titanium and aluminum is less than the mole number of the ether in the homogeneous liquid comprising titanium trichloride, an additional Lewis acid may be preferably added to assist precipitation.
As the Lewis acid used for the above purpose, mention may 'c made of Lewis acids having =tronger acidity than titanium lll i ' .
- ~. .
trichloride, for example, organo-aluminum compounds having the general formula:
AQRn'X3 n' ' ' (3) wherein R4 represents an alkyl radical having 1 - 8 carbon atoms, n' is a number of 0, 1, 1.5 or 2 and X represents a halogen atom, titanium tetrachloride, boron tri~luoride, boron trichloride, antimony pentachloride, gallium trichloride, ferric trichloride, tellurium dichloride, stannic tetrachloride, vanadium tetrachloride, thallium pentachloride, zirconium tetrachloride, beryllium dichloride, and the corresponding bromides and hydroxyhalides. Among them most preferred are organo-aluminum compounds of the general formula (3) and titani~
tetrachlorideO
The amount of the Lewis acid to be added may preferably be less than 5 moles per mole o the titanium in the homogeneous liquid. Such an amount of the Lewis acid is added to the homogeneous liquid before the precipitation is completed.
The precipitation may be effected in multi-steps of different temperatures. For example, a samll portion is precipitated at a relatively low temperature and then the temperature is raised to cause a major portion to precipitate in the presence of the small portion of previously precipitated fine-granular solid titanium trichloride~ More illustratively, first of all, the homogeneous liquid is heated to a relatively low temperature of 20 - 70C to precipitate 1 - 50 wt% of the total theoretical precipitation amount of finer-granular solid purple titanium trichloride~ and then the temperature l is raised to an elevated temperature of 45 - 150~C to precipi-¦¦ tate the remaining portion of fine-granular solid purple ~ titanium trichloride. - 12 -!l Il .
., .
A seeding procedure may also be recommended with respect to the precipitation, in which fine-granular solid titanium txichloridel for example, having an average particle l diameter of 0.01 - 50 ~ is previously added as seed crystals S ¦ to the homogeneous liquid comprising titanium trichloride before the precipitation is commenced. The kind of solid titanium trichloride addPd as seed crystals is not particularly restricted. Any of titanium trichloride catalysts prepared l by the conventional methods may be employed, while fine-¦ granular solid titanium trichloride prepared by precipitatingrom the homogeneous liquid comprising titanium trichloride according to the above-described method is preferable. The amount of solid titanium trichloride to be added is, for l example, OrO05 ~ SO wt~, preferably 0.01 - 25 wt% of the ¦ theoretical amount of solid titanium trichloride precipitated.
According to the above-described method (A) or (B), a fine-granular solid purple precipitate of titanium trichloride is obtained. This solid titanium trichloride may either be I directly used for polymerization or be pretreated with an 20 ¦ organo-aluminum compound, an olefin monomer such as propylene and/or an organic carboxylate (to be described hereinafter) according to the conventional manner before it is used for polymerization.
I ~he component (b), or the organo-aluminum compound of the catalyst system according to this invention includes, ll li by way of illustration, trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, etc.; and alkyl aluminum halides such as dimethyl aluminum chloride, diethyl aluminum chloride, ethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum sesquichlo-ride etc. A mixture of an aluminum halide and a trialkyl aluminum may also be employed. Among these preferred are dialkyl aluminum halides and most pre~erred is diethyl aluminum chloride.
In addition to the above-described two components (a~
and (b), organic carboxylate is used as a third component according to the catalyst system of ~his invention.
As the organic carhoxylate, mention may be made o~
a compound having the general formula:
R (COOR)n .............. (4) wherein R5 and R6 represent a hydrocarbon rad~cal having 1 - 20 carbon atoms such as an alkyl, aralkyl, alkenyl, ary~, alkaryl and alkenyl aryl radical, wherein a hydrogen atom of each hydrocarbon radical may be replaced with an alkyl amino radical, an amino radical, an alkyl amino radical, a nitrogen-containin~
~0 substituent such as nitro, an oxygen-containing substituent such as alkoxy, an halogen atom or the like, and n is a number of 1 - 3.
By way of illustration, included are methyl acetate, ethyl acetate, propyl acetate, butyl acetate~ methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl Il ~
107630S) acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, propyl me~hacrylate, ethyl oleate, ethyl stearate/ e~hylphenyl acetate, methyl benzoate, e~hyl benzoate, butyl benzoate, methyl p-toluate, propyl p-toluate, butyl p-toluate, ethyl p-ethylbenzoate, propyl m-ethylbenzoate, butyl o-ethylbenzoate, ethyl p-phenylbenzoate, propyl p-phenylbenzoate, butyl p-phenylbenzoate, ethyl p-methoxybenzoate, propyl p-methoxybenzoate, butyl p-methoxybenzoate, ethyl p-dimethylaminobenzoate, propyl m-dimethylbenzoate, butyl p-dimethyl benzoate, methyl cinnamate, ethyl cinnamate, e~hyl phenylacetate, dimethyl oxalate, diethyl malonate, dimethyl terephthalate, etc.
The proportion of the above-described three components o the catalyst system according to this invention is so selected that the molar ratio of (a) solid titanium trichloride to (b) the organo-aluminum compound to (c) the organic carboxylate is usually 1 : (0.5 - 20) : (0.01 - 1), preferably 1 : (1 - 5~ :
. (0.1 - 0.2).
According to this invention, the catalyst system is l prepared from the three components, the solid titanium trichlo-¦ ride~ the organo-aluminum compound and the organic carboxylate~
Any suitable known method may be applied to the preparation of this catalyst system. For example, a simple method is to mix the above-described three components in a solvent which l is used as a polymerization solvent in the subsequent step.
¦ The conditions with respect to temperature, atmosphere, solven~
and the like during the preparation of the catalyst system are not particularly restricted. The same conditions as those for polymerization are, of course, adopted when the polymeriza-tion is carried out immediately after the catalyst is prepared.
On the other hand, it is possible to mix the three components l at about room temperature using a partial or total amount of ¦ the solvent for polymerization when the catalyst is prepared in advance, although conditions close to those for polymerization are preferred.
According to the process of this invention, polymeriza-tion of propylene or copolymerization of propylene with another olefin is carried out using the catalyst system prepared as above.
Examples of the olefin to be copolymerized with propy-lene are ethylene, butene-l, 3-methyl butene-l, 4-methyl pentene-l, pentene-l, hexene-l, etc. and mixtures thereof.
In the case of copolymerization, propylene should be copolymerized with a small amount of an olefin other than propylene so that the resulting copolymer may not lose the properties inherent to polypropylene. The amount of an olefin other than propylene may be in the range of 0.1 - 10 ~ by weight, preferably 1 - 8 ~ by weight based on the total amount of the resulting propylene copolymer This kind of polymerization of propylene is usually conducted in an aliphatic hydrocarbon solvent such as hexane, heptane, cyclohexane, pentane, butane and propane, while the polymerization may preferably be conducted without any solvent ~bulk polymerization) in a certain case. Furthermorel the process ; ¦ of this invention may also be applied to vapor phase polymeriza-tion.
I!
Polymerization conditions may vary within very wide ranges. Though the polymerization can be conduc~ed at a pressure below atmospheric pressure, a pressure in the range of 1 - 150 atm, preferably 5 - 30 atm is selected in order to obtain a S commercially` advantageous rate of polymerization. The polymeriza-tion temperature is usually selected in the range of 40 - 100C.
preferably 50 - 70C.
The polymerization may be carried out in either a batchwise or a continuous manner. It is also contemplated to modify the molecular weigh~ o~ a polymer obtained. To this end, a suitable amount of a known molecular weight modifier such as hydrogen and diethyl zinc may be added to the polymerization system.
According to the above-described manner, polypropylene is certainly obtained~ The process of this invention has the following advantages.
(1) A polymer product obtained according to this invention is highly crystalline and contains only a small or negligible amount of an amorphous polymer which is substantially valueless in industry.
(2) The amorphous polymer contained in the powdery polymer product according to this invention has unique solubility in a hydrocarbon solvent which decreases at a higher rate as the temperature falls than that of amorphous polymers obtained by 1 the conventional process. Therefore, the behaviox of a slurry l during polymerization and after-treatment is very good and the 1~6300 operating stability is also very high when compared with the conventional process.
~3) The polymer insoluble in the hydrocarbon solvent has a remarkably higher bulk density than those obtained by the S conventional process. This also causes an improvement in the behaviour of the slurry.
(4) The polymer obtained according to this invention, parti-cularly the polymer product containing the amorphous polymer which is insoluble in the hydrocarbon solvent at temperatures near the polymerization or after-treatment temperature~ shows more improved product characteris~ics than the conventional polymers. Therefore, the polymer obtained according to this invention can be directly formed into products such as ~ilms, tapes, flat yarns, molded articles or the like without removing the amorphous polymer. This act in combination with the reduced solubility of the amorphous polymer in the hydrocarbon solvent contxibutes ~o an improvement in rate of conversion of a charge monomer to a useful polymer.
The following examples illustrate ~he invention. They are set forth as a further description, but are not to ~e con~t-rued as limiting the invention thereto. In the examples and comparative examples, the abbreviations s~and for the ollowing mean~ngs.
i) K : polymerization ac~ivity repre~ented in ~erms of the amount (g) of polypropylene produced per gram of the catalyst-constituting titani~m trichloride component per hour at an olefin-charge pressure of 1 ky/cm2.
1~)~6300 ii) CE : catalytic eficiency represented in terms of the amount (g) of polypropylene produced per gxam of the catalyst-constituting titanium trichloride component.
iii)I.I. : isotactic index represen~ed in terms of the amount (wt~) of the polymer remained after a 6-hour extraction with boiling n-heptane in a modified-type Soxhlet apparatus. Since the amorphous polymer which causes physical properties to decrease is soluble in boiling n-heptane, I.I. shows the yield of the crystalline polymer.
iv) Pg : bulk density (g/cc) measured according to JIS 6721.
v) MFI : melt flow index (g/lO min.~ measured according to ¦ vi) YS : strength at primary yield point (kg/cm2) measured ¦ according to ASTM D-412.
¦ vii)TI : tensile impact strength (kg-cm/cm2) measured accord~
¦ ing to ASTM D-1822.
Examples l - 5:
Pre aration of titanium trichloride P _ _ A l-liter four-necked flask is charged with 0.3 Q
of n-heptane, 180 mmols of titanium tetrachloride and 180 mmols of n-octyl ether. With stirring at room temperature, 60 mmols of diethyl aluminum chloride is added dropwise in the flas]c, obtaining a homogeneous brown solutionO With further stirring, this solution is heated up to 90C, while a purple precipitate 107630l~
of titanium trichloride is observed in the course of heating.
The solution is stirred for 1 hour at 90~CO The resulting precipitate is separated by decantation from the mother li~uor ¦ and then washed with n-heptane (from which oxygen and water S ¦ have been removed). The X-ray diffraction of this purple pre-¦ cipitate shows that the precipitate mainly consists o~ ~-type ¦ titanium trichloride. Aluminum is under the sensible level ¦ and 15 wt% of octyl ether is contained.
I B. Polymerization o~ Propylene I
¦ A 2-li~er induction rotary ~ype autoclave which has been purged and filled with propylene gas is charged with 1 Q
of n-hexane ~rom which oxygen and water have been removed).
Thereater, a given amount of ~he purple precipitate (titanium trichloride catalyst) prepared in the abov~, diethyl aluminum monochloride in an amount to give an atomic ratio o Al/Ti of ¦ 4, and a given amount of a carboxylate are added in this order.
¦ After hydrogen gas is foxcedly introduced to a partial pressure ¦ of 0.5 kg/cm2, the autoclave is heated to 60C. Stirring is ¦ performed and thereafter propylene gas is fed from a feed pipe ¦ to a partial pressure of 20 kg/cm . ~hile maintaining this ¦ partial pxessure of 20 kg/cm2, polymerization is continued for ¦ 5 hours. Ater the reaction, the unreacted propylene gas is ¦ purged and the contents including n-hexane are taken out from ¦ the autoclave. The liquid phase is evaporated and the residue ¦ is dried. The resulting polypropylene powder including the smorphous polymer is weighed. Thereafter, the polypropy1ene ~ 20 I
!l 107t;300 product is washed 3 ~imes with methanol containing 2 % of hydro-chloric acid at its boiling point for 3 hours. The amorphous polymer is not removed. The conditions for polymerization and the results are shown in Table 1.
comparative Example 1:
Following the procedure (B) of Example 1, polymeriza-¦ tion is carried out, except that the amount of the titanium ¦ trichloride catalyst used is changed and no carboxylate is ¦ added. The results are shown in Table 1.
¦ Comparative Example 2:
Polymerization is conducted in the same manner as described in Example l-B, except that a given amount of a commercially available catalyst C-141, TiC13 1/3 AlC13) is used instead of the titanium trichloride catalys~ prepared according to the invention. A given amount of ethyl benzoate ¦ is used as the carboxyate. The results are shown ¦ in Table 1.
¦ The results of Comparative Example 1 are also shown ¦ in Table 1 as an example in which polymerization is conducted ¦ in the same manner as described in Example l-B, except that the titanium trichloride catalyst is used in a different amount and the carboxylate is not used.
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The reduction may be effected by any of the following different procedures.
(a) An organo-aluminum compound is added to a homogeneous liquid consisting of titanium tetrachloride and an ether, or vice versa.
(b) A homogeneous liquid consisting of an organo-aluminum compound and an ether is added to titanium tetrachloride, or vice versa.
~c) A homogeneous liquid consisting of an organo-aluminum compound and an ether is added to a homogeneous liquid consisting of titanium tetrachloride and an ether, or vice versa.
(d) Titanium tetrachloride~ an ether and an organo-aluminum compound are mixed with each other in any suitable sequence at a temperature a-t which reduction cannot occur~ for example, at a temperature below -30C and the mixture is then heated to a given reduction temperature~
Titanium tetrachloride, an ether and an organo-aluminum compound may be used either in the form of pure reagents or in the form o reagents diluted wi~h an apropriate solvent in the above procedures. It is particularly desired to dilute the organo-aluminum compound with a hydrocarbon solvent.
The reduction temperature is selected from within the range of -30 - 50C, preferably 10 - 40C.
The reduction of titanium tetrachloride with the organo-aluminum compound in the presence of the ether according to any of the above-described procedures results in a homogeneous li~uid which is a homogeneous solution or mixture comprising o titanium trichloride and the ether, besides organo-aluminum compound and unreacted titanium tetrachloride etc. in a certain case. This solution is soluble in the hydrocarbon solvent and is brown or greenish brown.
It is also preferable that iodine or an iodide is coexistent with the ether during the reduction of titanium tetrachloride in the above-described method (A). In this case, iodine or an iodide may preferably be added before the reduction of titanium tetrachloride is effected~ It is also possible to add iodine or iodide after the reduction is com-menced, so far as the reduction has not substantially been completed.
Method (B) will now be described. In this method, solid titanium trichloride used as a star-ting material is ¦ treated with an ether, if desired, in the presence of an appropriate hydrocarbon solvent to form a homogeneous liquid I comprising titanium trichloride. As the solid titanium trichlo-¦ ride, use may be made of, for example, a solid form of titanium trichloride prepared by reducing titenium tetraahloride with 107~300 hydrogen gas, aluminum or an organo-aluminum compound, a powder form of titanium trichloride prepar~d by fi~ely grinding the above-prepared solid titanium trichloride, or another foxm prepared by heating the above-prepared soli~ titanium trichloride. A purified produc~ of the above solid titanium trichloride which is obtained by removing the impurities thererom may also be used.
Examples of the ether and the hydrocarbon solvent used for obtaining a homogeneous liquid containing the above-described titanium trichloride include the same compounds as those mentioned with reference to method (A).
The ether is used in a suitable amount in method (B) so that the mola~ ratio of the ether to titanium trichloride may be above 1/1, preferably (1-5)/1, most pxeferably (1-2)/1.
~5 The treatment of solid titanium trichloride with the ether may be carried out in any desired manner, preferably by mixing them at a temperature of -30 - 120C, preferably 10 -50C. Such a treatment is usually carried out in the presence of a hydrocarbon solvent which is selected depending upon the ether used as described with reference to method (A).
It is to be noted that ethers of the formula (1) wherein Rl and R2 represent an alkyl radical having more than 6 carbon atoms are preferably used in method (B).
A homogeneous liquid formed according to method (B) is the same as that formed according to method (A), so far l as the same reagents are used.
As apparent from the above, either method (A) or (B) can advantageously provide a homogeneous liquid containing titanium trichloride.
In a subsequent step, fine-granular titanium trichloride having a high catalytic activity to olefin polymerization i5 precipitated in the presence of a Lewis acid from the above-prepared homogeneous liquid comprising titanium trichloride. The precipitation is not limited to any particular method, but can be performed according to any of widely varying methods. For example the above-prepared homogeneous liquid as such or, if desired, after added with the above-mentioned hydrocarbon diluent, is heated in th~ presence of a Lewis acid to a temperature of usually from 20 ~ 150C, preferably from 40 - 120C, most pre-fexably from 60 - 100C to induce the precipitation, and then lS maintained at the same temperature for a certain period of time to ensure the precipitation until completion.
In this case, in order to facilitate the precipitation, the amount of aforementioned hydrocarbon solvent is prefexred to be not less than twice by weight of the ether.
In a certain case where the total mole number of titanium and aluminum is less than the mole number of the ether in the homogeneous liquid comprising titanium trichloride, an additional Lewis acid may be preferably added to assist precipitation.
As the Lewis acid used for the above purpose, mention may 'c made of Lewis acids having =tronger acidity than titanium lll i ' .
- ~. .
trichloride, for example, organo-aluminum compounds having the general formula:
AQRn'X3 n' ' ' (3) wherein R4 represents an alkyl radical having 1 - 8 carbon atoms, n' is a number of 0, 1, 1.5 or 2 and X represents a halogen atom, titanium tetrachloride, boron tri~luoride, boron trichloride, antimony pentachloride, gallium trichloride, ferric trichloride, tellurium dichloride, stannic tetrachloride, vanadium tetrachloride, thallium pentachloride, zirconium tetrachloride, beryllium dichloride, and the corresponding bromides and hydroxyhalides. Among them most preferred are organo-aluminum compounds of the general formula (3) and titani~
tetrachlorideO
The amount of the Lewis acid to be added may preferably be less than 5 moles per mole o the titanium in the homogeneous liquid. Such an amount of the Lewis acid is added to the homogeneous liquid before the precipitation is completed.
The precipitation may be effected in multi-steps of different temperatures. For example, a samll portion is precipitated at a relatively low temperature and then the temperature is raised to cause a major portion to precipitate in the presence of the small portion of previously precipitated fine-granular solid titanium trichloride~ More illustratively, first of all, the homogeneous liquid is heated to a relatively low temperature of 20 - 70C to precipitate 1 - 50 wt% of the total theoretical precipitation amount of finer-granular solid purple titanium trichloride~ and then the temperature l is raised to an elevated temperature of 45 - 150~C to precipi-¦¦ tate the remaining portion of fine-granular solid purple ~ titanium trichloride. - 12 -!l Il .
., .
A seeding procedure may also be recommended with respect to the precipitation, in which fine-granular solid titanium txichloridel for example, having an average particle l diameter of 0.01 - 50 ~ is previously added as seed crystals S ¦ to the homogeneous liquid comprising titanium trichloride before the precipitation is commenced. The kind of solid titanium trichloride addPd as seed crystals is not particularly restricted. Any of titanium trichloride catalysts prepared l by the conventional methods may be employed, while fine-¦ granular solid titanium trichloride prepared by precipitatingrom the homogeneous liquid comprising titanium trichloride according to the above-described method is preferable. The amount of solid titanium trichloride to be added is, for l example, OrO05 ~ SO wt~, preferably 0.01 - 25 wt% of the ¦ theoretical amount of solid titanium trichloride precipitated.
According to the above-described method (A) or (B), a fine-granular solid purple precipitate of titanium trichloride is obtained. This solid titanium trichloride may either be I directly used for polymerization or be pretreated with an 20 ¦ organo-aluminum compound, an olefin monomer such as propylene and/or an organic carboxylate (to be described hereinafter) according to the conventional manner before it is used for polymerization.
I ~he component (b), or the organo-aluminum compound of the catalyst system according to this invention includes, ll li by way of illustration, trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, etc.; and alkyl aluminum halides such as dimethyl aluminum chloride, diethyl aluminum chloride, ethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminum sesquichlo-ride etc. A mixture of an aluminum halide and a trialkyl aluminum may also be employed. Among these preferred are dialkyl aluminum halides and most pre~erred is diethyl aluminum chloride.
In addition to the above-described two components (a~
and (b), organic carboxylate is used as a third component according to the catalyst system of ~his invention.
As the organic carhoxylate, mention may be made o~
a compound having the general formula:
R (COOR)n .............. (4) wherein R5 and R6 represent a hydrocarbon rad~cal having 1 - 20 carbon atoms such as an alkyl, aralkyl, alkenyl, ary~, alkaryl and alkenyl aryl radical, wherein a hydrogen atom of each hydrocarbon radical may be replaced with an alkyl amino radical, an amino radical, an alkyl amino radical, a nitrogen-containin~
~0 substituent such as nitro, an oxygen-containing substituent such as alkoxy, an halogen atom or the like, and n is a number of 1 - 3.
By way of illustration, included are methyl acetate, ethyl acetate, propyl acetate, butyl acetate~ methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl Il ~
107630S) acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate, propyl me~hacrylate, ethyl oleate, ethyl stearate/ e~hylphenyl acetate, methyl benzoate, e~hyl benzoate, butyl benzoate, methyl p-toluate, propyl p-toluate, butyl p-toluate, ethyl p-ethylbenzoate, propyl m-ethylbenzoate, butyl o-ethylbenzoate, ethyl p-phenylbenzoate, propyl p-phenylbenzoate, butyl p-phenylbenzoate, ethyl p-methoxybenzoate, propyl p-methoxybenzoate, butyl p-methoxybenzoate, ethyl p-dimethylaminobenzoate, propyl m-dimethylbenzoate, butyl p-dimethyl benzoate, methyl cinnamate, ethyl cinnamate, e~hyl phenylacetate, dimethyl oxalate, diethyl malonate, dimethyl terephthalate, etc.
The proportion of the above-described three components o the catalyst system according to this invention is so selected that the molar ratio of (a) solid titanium trichloride to (b) the organo-aluminum compound to (c) the organic carboxylate is usually 1 : (0.5 - 20) : (0.01 - 1), preferably 1 : (1 - 5~ :
. (0.1 - 0.2).
According to this invention, the catalyst system is l prepared from the three components, the solid titanium trichlo-¦ ride~ the organo-aluminum compound and the organic carboxylate~
Any suitable known method may be applied to the preparation of this catalyst system. For example, a simple method is to mix the above-described three components in a solvent which l is used as a polymerization solvent in the subsequent step.
¦ The conditions with respect to temperature, atmosphere, solven~
and the like during the preparation of the catalyst system are not particularly restricted. The same conditions as those for polymerization are, of course, adopted when the polymeriza-tion is carried out immediately after the catalyst is prepared.
On the other hand, it is possible to mix the three components l at about room temperature using a partial or total amount of ¦ the solvent for polymerization when the catalyst is prepared in advance, although conditions close to those for polymerization are preferred.
According to the process of this invention, polymeriza-tion of propylene or copolymerization of propylene with another olefin is carried out using the catalyst system prepared as above.
Examples of the olefin to be copolymerized with propy-lene are ethylene, butene-l, 3-methyl butene-l, 4-methyl pentene-l, pentene-l, hexene-l, etc. and mixtures thereof.
In the case of copolymerization, propylene should be copolymerized with a small amount of an olefin other than propylene so that the resulting copolymer may not lose the properties inherent to polypropylene. The amount of an olefin other than propylene may be in the range of 0.1 - 10 ~ by weight, preferably 1 - 8 ~ by weight based on the total amount of the resulting propylene copolymer This kind of polymerization of propylene is usually conducted in an aliphatic hydrocarbon solvent such as hexane, heptane, cyclohexane, pentane, butane and propane, while the polymerization may preferably be conducted without any solvent ~bulk polymerization) in a certain case. Furthermorel the process ; ¦ of this invention may also be applied to vapor phase polymeriza-tion.
I!
Polymerization conditions may vary within very wide ranges. Though the polymerization can be conduc~ed at a pressure below atmospheric pressure, a pressure in the range of 1 - 150 atm, preferably 5 - 30 atm is selected in order to obtain a S commercially` advantageous rate of polymerization. The polymeriza-tion temperature is usually selected in the range of 40 - 100C.
preferably 50 - 70C.
The polymerization may be carried out in either a batchwise or a continuous manner. It is also contemplated to modify the molecular weigh~ o~ a polymer obtained. To this end, a suitable amount of a known molecular weight modifier such as hydrogen and diethyl zinc may be added to the polymerization system.
According to the above-described manner, polypropylene is certainly obtained~ The process of this invention has the following advantages.
(1) A polymer product obtained according to this invention is highly crystalline and contains only a small or negligible amount of an amorphous polymer which is substantially valueless in industry.
(2) The amorphous polymer contained in the powdery polymer product according to this invention has unique solubility in a hydrocarbon solvent which decreases at a higher rate as the temperature falls than that of amorphous polymers obtained by 1 the conventional process. Therefore, the behaviox of a slurry l during polymerization and after-treatment is very good and the 1~6300 operating stability is also very high when compared with the conventional process.
~3) The polymer insoluble in the hydrocarbon solvent has a remarkably higher bulk density than those obtained by the S conventional process. This also causes an improvement in the behaviour of the slurry.
(4) The polymer obtained according to this invention, parti-cularly the polymer product containing the amorphous polymer which is insoluble in the hydrocarbon solvent at temperatures near the polymerization or after-treatment temperature~ shows more improved product characteris~ics than the conventional polymers. Therefore, the polymer obtained according to this invention can be directly formed into products such as ~ilms, tapes, flat yarns, molded articles or the like without removing the amorphous polymer. This act in combination with the reduced solubility of the amorphous polymer in the hydrocarbon solvent contxibutes ~o an improvement in rate of conversion of a charge monomer to a useful polymer.
The following examples illustrate ~he invention. They are set forth as a further description, but are not to ~e con~t-rued as limiting the invention thereto. In the examples and comparative examples, the abbreviations s~and for the ollowing mean~ngs.
i) K : polymerization ac~ivity repre~ented in ~erms of the amount (g) of polypropylene produced per gram of the catalyst-constituting titani~m trichloride component per hour at an olefin-charge pressure of 1 ky/cm2.
1~)~6300 ii) CE : catalytic eficiency represented in terms of the amount (g) of polypropylene produced per gxam of the catalyst-constituting titanium trichloride component.
iii)I.I. : isotactic index represen~ed in terms of the amount (wt~) of the polymer remained after a 6-hour extraction with boiling n-heptane in a modified-type Soxhlet apparatus. Since the amorphous polymer which causes physical properties to decrease is soluble in boiling n-heptane, I.I. shows the yield of the crystalline polymer.
iv) Pg : bulk density (g/cc) measured according to JIS 6721.
v) MFI : melt flow index (g/lO min.~ measured according to ¦ vi) YS : strength at primary yield point (kg/cm2) measured ¦ according to ASTM D-412.
¦ vii)TI : tensile impact strength (kg-cm/cm2) measured accord~
¦ ing to ASTM D-1822.
Examples l - 5:
Pre aration of titanium trichloride P _ _ A l-liter four-necked flask is charged with 0.3 Q
of n-heptane, 180 mmols of titanium tetrachloride and 180 mmols of n-octyl ether. With stirring at room temperature, 60 mmols of diethyl aluminum chloride is added dropwise in the flas]c, obtaining a homogeneous brown solutionO With further stirring, this solution is heated up to 90C, while a purple precipitate 107630l~
of titanium trichloride is observed in the course of heating.
The solution is stirred for 1 hour at 90~CO The resulting precipitate is separated by decantation from the mother li~uor ¦ and then washed with n-heptane (from which oxygen and water S ¦ have been removed). The X-ray diffraction of this purple pre-¦ cipitate shows that the precipitate mainly consists o~ ~-type ¦ titanium trichloride. Aluminum is under the sensible level ¦ and 15 wt% of octyl ether is contained.
I B. Polymerization o~ Propylene I
¦ A 2-li~er induction rotary ~ype autoclave which has been purged and filled with propylene gas is charged with 1 Q
of n-hexane ~rom which oxygen and water have been removed).
Thereater, a given amount of ~he purple precipitate (titanium trichloride catalyst) prepared in the abov~, diethyl aluminum monochloride in an amount to give an atomic ratio o Al/Ti of ¦ 4, and a given amount of a carboxylate are added in this order.
¦ After hydrogen gas is foxcedly introduced to a partial pressure ¦ of 0.5 kg/cm2, the autoclave is heated to 60C. Stirring is ¦ performed and thereafter propylene gas is fed from a feed pipe ¦ to a partial pressure of 20 kg/cm . ~hile maintaining this ¦ partial pxessure of 20 kg/cm2, polymerization is continued for ¦ 5 hours. Ater the reaction, the unreacted propylene gas is ¦ purged and the contents including n-hexane are taken out from ¦ the autoclave. The liquid phase is evaporated and the residue ¦ is dried. The resulting polypropylene powder including the smorphous polymer is weighed. Thereafter, the polypropy1ene ~ 20 I
!l 107t;300 product is washed 3 ~imes with methanol containing 2 % of hydro-chloric acid at its boiling point for 3 hours. The amorphous polymer is not removed. The conditions for polymerization and the results are shown in Table 1.
comparative Example 1:
Following the procedure (B) of Example 1, polymeriza-¦ tion is carried out, except that the amount of the titanium ¦ trichloride catalyst used is changed and no carboxylate is ¦ added. The results are shown in Table 1.
¦ Comparative Example 2:
Polymerization is conducted in the same manner as described in Example l-B, except that a given amount of a commercially available catalyst C-141, TiC13 1/3 AlC13) is used instead of the titanium trichloride catalys~ prepared according to the invention. A given amount of ethyl benzoate ¦ is used as the carboxyate. The results are shown ¦ in Table 1.
¦ The results of Comparative Example 1 are also shown ¦ in Table 1 as an example in which polymerization is conducted ¦ in the same manner as described in Example l-B, except that the titanium trichloride catalyst is used in a different amount and the carboxylate is not used.
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The polypropylene products in;-luding all the amorphous polymer obtained in Examples 1, 2 and 5 and Comparative Examples 1 and 2 are washed 3 times with n-heptane containing 5 % of 1-propanol at 70C for 3 hours to remove a part of the amorphous polymer. The resulting polypropylene is tested for various mechanical properties, the results are shown in Table 2.
Table 2 l Amorphous polymer Mechanical properties l I.I. MFI YS TI
¦ Example 1 included 94.4 4.9 349 65 removed 97.0 4.8 351 65 ¦ Example 2 included 95.2 6.3 346 60 I removed 97.9 6.4 350 59 ¦ Example 5 included 95.7 5.7 340 73 ¦ removed 98.1 5~8 348 72 1 Comparative included 88.6 5.8 30.3 58 Example 1 removed 90.3 5.8 305 58 Comparative included 93.3 6.1 321 53 Example 2 removed 94.3 6.2 330 52 It is obvious from Table 2 that the products of ~0 ¦ Examples according to the invention show more excellent mecha-nical properties than those of Comparative Examples, irrespective of the removal of the amorphous polymer. This means that polypropylene products obtained according to the invention can l be practically applied without removing the amorphous polymer formed as a by-product.
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~ 1076300 Example 6: ¦
Polymerization is conducted in the same manner as described in Example l-B, except that titanium trichloride is 47.9 mg and ethyl p-methoxybenzoa~e as a carboxylate is added so S as to give a molar ratio of the ester ~o titanium trichloride of 0.17. There is obtained 541 g of a polypropylene powder.
CE K II PB MFI YS TI
11,300 m ~ o. ~4 5.2 3S7 68 Examples 7 - 10:
~olymerization is conducted in the same manner as described in Example 1-~, except that the amount of the titanium trichloride catalyst is ~aried and carboxylate prepared in the following manner is used. The results are shown in Table 3~
As the carboxylate, a product obtained by reacting a lS carboxylate with diethyl aluminum monochloride (DEA) is used.
To this end, the carboxylate is firs~ dissolved in heptane or toluene to obtain a 0.25 mmol/ml solution. With stirring in argon atmospherey DEA is added dropwise to the solution at room tempera-tùre, the molar amount of DEA being equal to that of the carboxy-late. After the addition, the mixture is heated at 60C for 1 hour and then cooled, which product is ready for use in polymeri-za~ion.
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Reference Example:
The polypropylene products in;-luding all the amorphous polymer obtained in Examples 1, 2 and 5 and Comparative Examples 1 and 2 are washed 3 times with n-heptane containing 5 % of 1-propanol at 70C for 3 hours to remove a part of the amorphous polymer. The resulting polypropylene is tested for various mechanical properties, the results are shown in Table 2.
Table 2 l Amorphous polymer Mechanical properties l I.I. MFI YS TI
¦ Example 1 included 94.4 4.9 349 65 removed 97.0 4.8 351 65 ¦ Example 2 included 95.2 6.3 346 60 I removed 97.9 6.4 350 59 ¦ Example 5 included 95.7 5.7 340 73 ¦ removed 98.1 5~8 348 72 1 Comparative included 88.6 5.8 30.3 58 Example 1 removed 90.3 5.8 305 58 Comparative included 93.3 6.1 321 53 Example 2 removed 94.3 6.2 330 52 It is obvious from Table 2 that the products of ~0 ¦ Examples according to the invention show more excellent mecha-nical properties than those of Comparative Examples, irrespective of the removal of the amorphous polymer. This means that polypropylene products obtained according to the invention can l be practically applied without removing the amorphous polymer formed as a by-product.
Il ~ 23 -i ~I
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~ 1076300 Example 6: ¦
Polymerization is conducted in the same manner as described in Example l-B, except that titanium trichloride is 47.9 mg and ethyl p-methoxybenzoa~e as a carboxylate is added so S as to give a molar ratio of the ester ~o titanium trichloride of 0.17. There is obtained 541 g of a polypropylene powder.
CE K II PB MFI YS TI
11,300 m ~ o. ~4 5.2 3S7 68 Examples 7 - 10:
~olymerization is conducted in the same manner as described in Example 1-~, except that the amount of the titanium trichloride catalyst is ~aried and carboxylate prepared in the following manner is used. The results are shown in Table 3~
As the carboxylate, a product obtained by reacting a lS carboxylate with diethyl aluminum monochloride (DEA) is used.
To this end, the carboxylate is firs~ dissolved in heptane or toluene to obtain a 0.25 mmol/ml solution. With stirring in argon atmospherey DEA is added dropwise to the solution at room tempera-tùre, the molar amount of DEA being equal to that of the carboxy-late. After the addition, the mixture is heated at 60C for 1 hour and then cooled, which product is ready for use in polymeri-za~ion.
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Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for the polymerization of propylene in the presence of a catalyst system comprising (a) titanium trichloride, (b) an organoaluminum compound and (c) an organic carboxylate, an improvement which com-prises using as said titanium trichloride a finely granu-lated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium tri-chloride and an ether in the presence of a Lewis acid.
2. The process according to claim 1 wherein the titanium trichloride is a finely granulated, purple solid obtained by precipitation from a homogeneous liquid mixture or solution of titanium trichloride and an ether in the presence of a Lewis acid and a hydrocarbon solvent at a temperature in the range of 20 - 150°C.
3. The process according to Claim 2, wherein a small amount of olefin other than propylen is copolymerized with propylene.
4. The process according to Claim 3, wherein said olefin other than propylene is ethylene.
5. The process according to Claim 3, wherein said copolymerization is conducted so as to obtain a copolymer containing 0.1 - 10 % by weight of olefin other than propylene.
6. The process according to Claim 2, wherein said carboxylate is acetate, propionate, acrylate, methacrylate, benzoate, dialkylaminobenzoate, alkoxybenzoate, phenoxy-benzoate or cinnamate.
7. The process according to Claim 2, wherein said carboxylate is phenyl acetate, ethyl benzoate, methyl cinnamate, ethyl propionate, ethyl p-dimethylaminobenzoate, ethyl p-dibutylaminobenzoate, ethyl p-didodecylaminobenzoate, ethyl p-methoxybenzoate or ethyl p-phenoxybenzoate.
8. The process according to Claim 2, wherein said carboxylate is treated with an organoaluminum compound in advance.
9, The process according to Claim 2, wherein the molar ratio of (a) titanium trichloride to (b) an organo-aluminum compound to (c) an organic carboxylate is within the range of 1 : 0.5 - 20 : 0.01 - 1.
10. The process according to Claim 2, wherein said ether has a formula : R1-O-R2 and R1 and R2 are individually selected from the group consisting of alkyl and alkenyl radicals; and wherein said hydrocarbon solvent is selected from the group consisting of saturated aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and their halogenated derivatives.
11. The process according to Claim 10, wherein said R1 and R2 respectively have at least six carbon atoms; and wherein said hydrocarbon solvent is a saturated aliphatic hydrocarbon.
12. The process according to Claim 19 wherein at least one of said R1 and R2 have five or less carbon atoms;
and wherein said hydrocarbon solvent is an aromatic or alicyclic hydrocarbon.
and wherein said hydrocarbon solvent is an aromatic or alicyclic hydrocarbon.
13. The process according to Claim 2, wherein said Lewis acid is titanium tetrachloride.
14. The process according to Claim 2, wherein said temperature is within the range of 40 - 120°C.
15. The process according to Claim 2, wherein said heating is conducted in at least two separate stages.
16. The process according to Claim 2, wherein said homogeneous liquid is prepared by reducing titanium tetrachloride with an organoaluminum compound in the presence of an ether and a hydrocarbon solvent.
17. The process according to Claim 16, wherein the molar ratio of said ether to titanium tetrachloride is within the range of 1 : 0.05 - 5.
18. The process according to Claim 2, wherein said homogeneous liquid is prepared by mixing solid titanium tri-chloride with a dialkyl ether in which each alkyl radical has six or more carbon atoms and wherein said hydrocarbon solvent is a saturated aliphatic hydrocarbon.
19. The process of Claim 18, wherein the molar ratio of said ether to titanium trichloride is within the range of 1 - 5.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP477976A JPS5287490A (en) | 1976-01-19 | 1976-01-19 | Production of of polyolefins |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1076300A true CA1076300A (en) | 1980-04-22 |
Family
ID=11593299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA269,718A Expired CA1076300A (en) | 1976-01-19 | 1977-01-14 | Process for producing polypropylene |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5287490A (en) |
| CA (1) | CA1076300A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3246447A1 (en) * | 1981-12-17 | 1983-07-14 | Chisso Corp., Osaka | POLYPROPYLENE FOR PRODUCING HIGHLY STIFF MOLDED BODIES AND METHOD FOR PRODUCING THE SAME |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5426891A (en) * | 1977-08-02 | 1979-02-28 | Mitsui Petrochem Ind Ltd | Preparation of olefin copolymer |
| JPS5636505A (en) * | 1979-09-04 | 1981-04-09 | Sumitomo Chem Co Ltd | Production of olefin polymer |
| JPS58104907A (en) * | 1981-12-17 | 1983-06-22 | Chisso Corp | Polypropylene for molded article having high rigidity and its preparation |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH543546A (en) * | 1971-03-23 | 1973-10-31 | Solvay | Alpha-olefin polymerization catalytic system |
-
1976
- 1976-01-19 JP JP477976A patent/JPS5287490A/en active Granted
-
1977
- 1977-01-14 CA CA269,718A patent/CA1076300A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3246447A1 (en) * | 1981-12-17 | 1983-07-14 | Chisso Corp., Osaka | POLYPROPYLENE FOR PRODUCING HIGHLY STIFF MOLDED BODIES AND METHOD FOR PRODUCING THE SAME |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS559404B2 (en) | 1980-03-10 |
| JPS5287490A (en) | 1977-07-21 |
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