Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1997-12-04
2000-07-18
Wu, David W.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
5261246, 5261253, 526153, 526128, C08F11006
Patent
active
06090903&
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a propylene homopolymer. More particularly, the present invention relates to a propylene homopolymer having less xylene-soluble component and an extremely high isoblock content in xylene-insoluble component.
TECHNICAL BACKGROUND
Many proposals have been made and known for a process for the polymerization of olefins in the presence of a catalyst formed by a solid catalyst component comprising a titanium halide compound, a magnesium compound and an electron donor compound as essential components, an organic aluminum compound and a third component such as silicon compound. Further, a process by which a crystalline polyolefin having a high stereoregularity can be obtained in the presence of such a catalyst in a high yield has been extensively studied.
For example, JP-A-63-3010 (The term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-1-221405, JP-A-1-315406, JP-A-3-227309, JP-A-3-70711, and JP-A-4-8709 disclose a process for the production of a polymer having a high stereoregularity in a high yield in the presence of an olefin polymerization catalyst formed by a solid catalyst component prepared from dialkoxymagnesium and titanium tetrachloride as main starting materials, an organic aluminum compound and a third component such as silicon compound.
Further, various proposals have been made for an olefin polymerization catalyst formed by (a) a solid catalyst component comprising a halogenated aluminum compound, a magnesium compound and a halogenated titanium compound as essential constituents, (b) an organic aluminum compound and (c) a third component such as organic acid ester and silicon compound. For example, JP-A-55-161807 proposes a catalyst formed by magnesium chloride, halogenated titanium, an organic acid ester, a halogenated hydrocarbon compound, and a halogenated aluminum compound. JP-A-61-31402 discloses a process for the preparation of a polymer having a high stereoregularity in a high yield in the presence of a catalyst prepared from (a) a solid catalyst component obtained by a process which comprises reacting (i) a reaction product of a halogenated aluminum compound with a silicon compound with (ii) a magnesium compound, and then reacting the reaction product with a halogenated titanium compound and a phthalic acid ester, (b) an organic aluminum compound and (c) a silicon compound.
The foregoing various techniques focus on the development of a catalyst component which is active enough to allow the omission of a so-called deashing step, i.e., step of removing catalyst residues such as chlorine and titanium remaining in the polymer produced by the polymerization of propylene in the presence of a catalyst as well as on the enhancement of the yield of a stereoregular polymer or the durability of the polymerization activity. These techniques can provide excellent results on these purposes.
Referring to propylene polymer, on the other hand, for example, JP-A-7-25946 discloses a propylene polymer having a high crystallinity of boiling n-heptane-insoluble component, a high stereoregularity and an extremely long meso run-length.
The propylene polymer obtained by the foregoing conventional techniques exhibits a high heat deformation temperature, a high melting point and a high crystallization temperature and thus exerts considerably good effects in respect to rigidity and heat resistance. Thus, the propylene polymer obtained by the foregoing conventional techniques can be utilized for various molding uses such as extrusion molding into sheet, film or the like, blow molding and injection molding. However, some problems have been still left unsolved in the molding of polypropylene. In particular, if the foregoing polymer having a high rigidity is subjected to extrusion molding into sheet, film or the like, some troubles can occur such as breaking during high speed molding and loss of transparency of the resulting molded product.
As a method for solving these problems there has been commonly known a method which compri
REFERENCES:
patent: 5518973 (1996-05-01), Miro et al.
Processing Polyolefins on Single-Screw Extruders, Plastics Engineering/ Jun. '91, pp.31-34.
Kataoka Takuo
Saito Masayoshi
Lu Caixia
Toho Titanium Co., Ltd.
Wu David W.
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