Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-04-03
2002-01-08
Nutter, Nathan M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S210000, C525S221000, C525S222000, C525S232000, C525S239000, C525S240000, C525S241000
Reexamination Certificate
active
06337372
ABSTRACT:
TECHNICAL FIELD
This invention relates to processes for producing propylene//propylene/olefin block copolymers and propylene/propylene/olefin block copolymers produced thereby. More particularly, the invention relates to processes for producing propylene//propylene/olefin block copolymers which comprise a segment A comprising a polymer based on propylene and a segment B comprising a propylene/olefin random copolymer and have improved bulk density, particle morphology, impact resistance, stiffness and transparency, using a catalyst system for an olefin polymerization comprising as a main component a metallocene catalyst having an enhanced polymerization activity, and propylene//propylene/olefin block copolymers produced using the catalyst system.
BACKGROUND ART
Propylene//propylene/olefin block copolymers comprising a polymer segment based on propylene and a propylene/olefin random copolymer segment are excellent in stiffness and impact resistance, and have been used as propylene type copolymers for various moldings in the fields of automobiles, electric home appliances, large size sundry goods or the like.
Such propylene//propylene/olefin block copolymers have been produced by polymerizing propylene with propylene and other olefin(s) than propylene in the presence of a catalyst system which comprises an inorganic transition metal compound catalyst having titanium trichloride, titanium tetrachloride or the mixture thereof supported on a support such as magnesium chloride or the like, in combination with an organoaluminum compound, what is called a Ziegler-Natta catalyst system.
In recent years, many processes of producing propylene//propylene/olefin block copolymers have been proposed which comprise using metallocene catalyst systems comprising an organic transition metal compound having at least one &pgr;-electron conjugated ligand, i.e., a metallocene compound in combination with aluminoxane, in place of prior Ziegler-Natta catalyst system. Propylene//propylene/olefin block copolymers produced using these metallocene catalyst systems have various expected uses, because of the balance of stiffness and impact resistance being more improved than block copolymers produced using prior Ziegler-Natta catalyst system.
JPA-4-337308 discloses a process for the production of a propylene//propylene/olefin block copolymer which comprises polymerizing propylene alone or a propylene/ethylene mixture containing up to 6% by weight of ethylene, followed by copolymerizing so as to provide a weight ratio of ethylene units/propylene units in the polymer chain being from 10/90 to 95/5, in the presence of a homogeneous catalyst system comprising a cyclopentadienyl group-containing transition metal compound represented by a specific formula and an organoaluminum compound. JPA-5-202152 and JPA-6-206921 disclose processes for the production of polypropylene molding materials wherein a liquid propylene is polymerized in the first stage in the presence of a homogeneous catalyst system comprising an indenyl group-containing transition metal compound represented by a specific formula and an organoaluminum compound, to produce a crystalline polymer containing at least 95% by weight of polypropylene, and in the second stage propylene and ethylene are copolymerized in solution or in suspension (JPA-5-202152) and in gas phase (JPA-6-206921) in the presence of ethylene, to produce a non-crystalline ethylene/propylene copolymer containing 20-90% by weight of ethylene.
JPA-8-92337 discloses a block copolymer comprising a propylene polymer block with a propylene content of 100-80% by weight and an ethylene content of 0-20% by weight, and a copolymer block with a propylene content of 0-99.9% by weight, an ethylene content of 99.99-0.09% by weight and a polymerizable polyene compound of 0.01-60% by weight. The block copolymer is produced by carrying out the sequential steps of forming the propylene polymer block and forming the copolymer block, in the presence of a homogeneous catalyst system which comprises a transition metal compound catalyst including an inorganic titanium compound and various metallocene compounds and also a compound which reacts with the transition metal compound to form an ion complex, or a homogeneous catalyst system wherein an organometallic compound including an organoaluminum compound is further incorporated in said catalyst system.
JPA-9-316147 discloses a propylene//ethylene/&agr;-olefin block copolymer wherein a polypropylene component and a copolymer component of ethylene/&agr;-olefin of C
4
or more are block-copolymerized. The block copolymer is produced by polymerizing the polypropylene component and the ethylene/&agr;-olefin copolymer component in the presence of a homogeneous catalyst system which comprises a transition metal compound having a cyclopentadienyl ring, in combination with at least one compound selected from aluminoxane, a compound which reacts with the transition metal compound to form a stable anion and an organoaluminum compound.
JPA-6-287257 discloses a propylene//propylene/ethylene block copolymer produced by a process wherein propylene alone or propylene and ethylene are polymerized in the first stage under the condition of a propylene concentration in gas phase being 90 mol % or more, and in the second stage propylene and ethylene are copolymerized under the condition of a propylene concentration being less than 90 mol %, in the presence of a catalyst system which comprises a metallocene type transition metal compound, a product prepared by contacting clay, a clay mineral or an ion-exchange lamellar compound and an organoaluminum compound, and if necessary an organoaluminum compound.
JPA-6-172414 discloses a process for the production of a propylene//propylene/ethylene block copolymer which comprises carrying out a first polymerization wherein propylene alone or propylene and ethylene are polymerized in substantially gas phase in the presence of a catalyst system having a cyclopentadienyl ring-containing transition metal compound of a specific formula and aluminoxane supported on an organic porous polymer support, to produce a crystalline homopolymer of propylene or a copolymer of propylene and ethylene with an ethylene content of 5% by weight or less, and a second polymerization wherein propylene, ethylene and at least one comonomer selected from &agr;-olefins of C
4
-C
20
are copolymerized so as to provide a polymerization molar ratio of propylene/comonomer being from 0/100 to 80/20.
JPA-8-27237 discloses a process of producing an ethylene/propylene//propylene copolymer which comprises carrying out the polymerization step (1) wherein propylene and at least one comonomer selected from ethylene and &agr;-olefins of C
4
-C
20
are copolymerized so that a polymerization ratio in a molar ratio of propylene/comonomer will be in the range from 0/100 to 80/20, in the presence of at least one compound selected from a transition metal compound having a &pgr;-conjugated 5-membered ring ligand, aluminoxane, a reaction product of a boron compound and an organoaluminum compound, a Lewis acid and an ionic compound, more specifically a catalyst system having an indenyl series zirconocene and aluminoxane supported on a porous polypropylene support, and then carrying out the polymerization step (2) in the presence of the above catalyst and the polymer prepared in (1) to produce a crystalline propylene homopolymer or a propylene copolymer of propylene with at least one comonomer selected from ethylene and &agr;-olefins of C
4
-C
20
, the copolymer having a comonomer content of 10% by weight or less.
The above-described references state that the propylene//propylene/olefin block copolymers produced therein have well-balanced stiffness and impact resistance at ordinary temperature and low temperature, the stiffness being evaluated by flexural modulus, etc., and the impact resistance being evaluated by Izod impact strength, etc.
JPA-6-172414 and JPA-8-27237 state that the block copolymers produced therein are improved in particle morphology and bulk density.
Of the above-descri
Fujita Hiroyuki
Saito Jun
Ushioda Tsutomu
Uwai Toshihiro
Yahata Tsuyoshi
Chisso Corporation
Nutter Nathan M.
LandOfFree
Propylene/propylene/olefin block copolymer and process for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Propylene/propylene/olefin block copolymer and process for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Propylene/propylene/olefin block copolymer and process for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844033