US4923935A
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US
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Process for producing polyethylene of ultrahigh molecular weight
Assignee: Eneos Corp
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Filing: 1989-01-26
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Granted: 1990-05-08
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Expires: 2009-01-26
Abstract
Abstract A process for producing polyethylene of ultrahigh molecular weight having an intrinsic viscosity of 10-30 dl/g at 135° C. in decalin is disclosed which comprises at least the following two stages of polymerization reaction: (a) a first reaction stage where in ethylene is polymerized with use of a catalyst comprising a solid component containing at least Mg, Ti and/or Va and in the absence or presence of hydrogen of reduced concentration to produce 70-99.5 weight parts of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135° C. in decalin; and (b) a second reaction stage wherein a fresh feed of ethylene is polymerized in the presence of hydrogen of higher concentration to produce 30-0.5 weight parts of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135° C. in decalin.
Inventors
- 👤 Akira Sano
- 👤 Shigeki Yokoyama
- 👤 Yasunosuke Miyazaki
- 👤 Tetsujiro Kuroishi
- 👤 Kazuo Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:20
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
186 words
A process for producing polyethylene of ultra-high molecular weight having an intrinsic viscosity of 10-30 dl/g at 135° C. in decalin, which process consists essentially of the following two stages of polymerization reaction: (a) a first reaction stage wherein ethylene monomer is polymerized in a reaction vessel with use of a composite catalyst comprising a solid component containing at least magnesium, titanium and/or vanadium and an organoluminum compound in the presence of 0-10 mol percent of hydrogen at 0°-90° C. and at a pressure of 0-70 kg/cm 2 ·g. to produce 75-99 parts by weight of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135° C. in decalin; and (b) a second reaction stage wherein a fresh feed of ethylene monomer is introduced into the same reaction vessel and polymerized in the presence of 35-95 mol percent of hydrogen at 40°-100° C. and at a pressure of 0-70 kg/cm 2 ·g. while retaining the reaction product from the first reaction stage in said reaction vessel to produce 25-1 parts by weight of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135° C. in decalin.
Claim 2
Dependent Claim
186 words
A process for producing polyethylene of ultra-high molecular weight having an intrinsic viscosity of 10-30 dl/g at 135° C. in decalin, which process consists essentially of the following two stages of polymerization reaction: (a) a first reaction stage wherein ethylene monomer is polymerized in a reaction vessel with use of a composite catalyst comprising a solid component containing at least magnesium, titanium and/or vanadium and an organoluminum compound in the presence of 0-10 mol percent of hydrogen at 0°-90° C. and at a pressure of 0-70 kg/cm 2 ·g. to produce 75-99 parts by weight of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135° C. in decalin; and (b) a second reaction stage wherein a fresh feed of ethylene monomer is introduced into the same reaction vessel and polymerized in the presence of 35-95 mol percent of hydrogen at 40°-100° C. and at a pressure of 0-70 kg/cm 2 ·g. while retaining the reaction product from the first reaction stage in said reaction vessel to produce 25-1 parts by weight of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135° C. in decalin.
Claim 3
Dependent Claim
56 words
A process according to claim 1 wherein said organoaluminum compound is represented by the formula R.sub.3 Al, R.sub.2 AlX, RAlX.sub.2, R.sub.2 AlOR, RAl(OR)X, or R.sub.3 Al.sub.2 X.sub.3 where R is an alkyl group of 1 to 20 carbon atoms or an aryl or aralkyl group, R being identical or different, and X is a halogen atom.
Claim 4
Dependent Claim
23 words
The process according to claim 1 wherein said catalyst comprises a solid component having a titanium compound carried on a magnesium-containing solid compound.
Claim 5
Dependent Claim
78 words
The process according to claim 3 wherein said magnesium-containing compound is selected from the group consisting of a magnesium metal; a double salt, a mixed oxide, a carbonate, a chloride and a hydroxide, each containing both a silicon, aluminum or calcium metal and a magnesium atom; and a compound derived by treating an inorganic compound with an organic or inorganic oxygen-containing compound, an organic or inorganic sulfur-containing compound, a monocyclic or polycyclic aromatic hydrocarbon, or a halogen-containing compound.
Claim 6
Dependent Claim
109 words
The process according to claim 3 wherein said titanium compound is a tetravalent titanium compound represented by the formula Ti(OR).sub.n X.sub.4-n where R is an alkyl group of 1 to 20 carbon atoms or an aryl or aralkyl group, X is a hologen atom and n is 0≦n≦4, or a travalent titanium compound derived by reducing a titanium tetrahalide with hydrogen, aluminum, titanium or an organometallic compound in Groups I to III of the Periodic Table or by reducing an alkoxytitanium halide represented by the formula Ti(OR).sub.m x.sub.4-m where m is 0<m<4 and R and X are as defined above, with an organometallic compound in Groups I to III.
References Cited (Backward Citations)
US4786687A
Cited
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