Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1998-12-08
2001-02-06
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S119000, C526S125300, C526S125600, C502S104000, C502S111000, C502S125000, C502S126000, C502S127000
Reexamination Certificate
active
06184328
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a propylene-based polymer with excellent physical properties such as rigidity, surface hardness, heat resistance, water vapor barrier property, etc. which is suitable for use in automobiles, consumer electric goods and packaging materials, to a method for the production thereof, to a composition containing it and to a catalyst component for its polymerization and a method for its production.
BACKGROUND ART
Propylene-based polymers are generally inexpensive, and exhibit characteristic properties including transparency, mechanical strength, heat resistance, surface gloss, chemical resistance, oil resistance, rigidity, flex clacking resistance, etc., for which they thus have a wide range of uses as industrial materials, food packaging materials, cosmetic packaging materials, drug packaging materials, and the like.
As mentioned above, propylene-based polymers exhibit characteristics such as rigidity, impact resistance, etc., and are thus widely used in various production industries including automobiles, consumer electric goods, miscellaneous goods, and the like. Recently, producers are investigating the prospect of making products thinner in order to render them more light-weight and lower their cost, while increasing the surface strength in order to prevent damage to the surface thereof. That is, demand is increasing for propylene-based polymers which have high rigidity, high surface hardness and excellent impact resistance. Also, demand has continued to increase for a higher level of physical properties and workability, and particularly desired are the maintaining of the rigidity and strength at high temperatures, durability, and the improvement of the moldability of large-size moldings.
Regarding high rigidity and improved transparency and surface gloss of propylene-based polymers, there have been conventionally known methods which employ fillers such as I
a
and II
a
group metal salts of monocarboxylic acids (for example, sodium benzoate), III-IV group metal salts of dicarboxylic acids (for example, adipic acid) and aliphatic dicarboxylic acids (for example, aluminum adipate), dibenzylidene sorbitol derivatives, talc and the like, as nucleating agents (Japanese Examined Patent Publication (KOKOKU) No. 39-1809, Japanese Unexamined Patent Publication (KOKAI) No. 60-139731, etc.), and methods which create a wide distribution of the molecular weight of propylene-based polymers (Japanese Unexamined Patent Publication (KOKAI) Nos. 56-2307, 59-172507, and 62-195007, etc.).
However, although use of these nucleating agents results in improvement in the aforementioned physical properties, it cannot be said that they are necessarily sufficient for all uses.
Consequently, it has been desired to obtain propylene-based polymers suitable as materials for automobiles, consumer electric goods and packaging materials, which have excellent mechanical strength including impact resistance, rigidity, etc. as well as surface hardness and heat resistance, at the same time lowering the density of the products to render them more thin by reducing the amount of fillers such as talc and the like.
Furthermore, efforts are continuing to improve the stereoregularity (isotacticity) of propylene-based polymers, widen their molecular weight distribution, increase their strength and durability which depend on the molecular weight distribution, and improve the moldability in extrusion molding, blow molding and the like.
Of these efforts, the development particularly of catalysts with high activity and producing high isotacticity are recently being ardently studied. All are catalyst systems comprising a solid catalyst component containing magnesium, titanium, a halogen and an electron-donating compound as essential components, with an organoaluminum and another electron-donating compound, and examples thereof are disclosed in Japanese Unexamined Patent Publication (KOKAI) Nos. 57-63310, 58-32604, 58-83006, 59-206408, 59-219311, 60-130607, 61-209207, 61-211309, 62-72702, 62-104811, 62-11705, 63-199703, 63-264609, 1-126306, 1-311106, 3-62805, 3-70710, 4-103604, 4-114009 and 4-202505.
The present inventors have also made recent disclosures in this regard in Japanese Unexamined Patent Publication (KOKAI) Nos. 4-43407, 4-149217, 4-178406, 4-180903, 4-185613, 4-198202, 4-198204, 5-9209 and 5-287019.
The propylene-based polymers disclosed in the preceding publications have a xylene-extraction insoluble portion of less than 99% and an isotactic pentad ratio (mmmm) of methyl groups in the polypropylene of at most around 93-98%, as measured by
13
C nuclear magnetic resonance spectroscopy (hereunder abbreviated to
13
C-NMR), and thus there have been limits to the improvement in the various physical properties such as rigidity and heat resistance.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a propylene-based polymer which has excellent rigidity, surface hardness, heat resistance, transparency, surface gloss, water vapor barrier property, etc., without any loss of the original physical properties of propylene-based polymers, which is suitable for use in automobiles, consumer electric goods and packaging materials, and a method for its production, as well as a composition containing it, a catalyst component for its polymerization and a method for the production thereof.
We the present inventors, as a result of a multitude of research regarding methods of overcoming the above mentioned problems, have discovered that the above mentioned problems are overcome with a propylene-based polymer in which (1) the xylene-extraction insoluble portion (XI) is 99.0 wt % or greater, (2) the isotactic pentad ratio (IP) is 98.0% or greater as measured by
13
C nuclear magnetic resonance spectroscopy, (3) the isotactic average chain length (N) is 500 or greater, and (4) the total amount of each of the fractions obtained by column separation of the xylene insolubles whose average chain length (N
f
) is 800 or greater accounts for 10 wt % or more of the entirety, and thus the present invention has been completed.
BEST MODE FOR CARRYING OUT THE INVENTION
A concrete explanation of the characteristics of the propylene-based polymer according to the present invention will now be given.
(1) The xylene-extraction insoluble portion (XI) is the percent by weight of the polymer which is insoluble in xylene at 25° C. Specifically, it is the percent by weight of the polymer which is first dissolved in ortho-xylene at 135° C. and then precipitated at 25° C. The XI of the propylene-based polymer of the present invention is 99.0% or greater, preferably 99.5% or greater, and more preferably 99.7% or greater. If the XI is less than 99.0% then the polymer will lack the desired rigidity, heat resistance, surface hardness, surface gloss, transparency, water vapor barrier property, etc.
(2) The isotactic pentad ratio of the polypropylene molecular chain (hereunder sometimes abbreviated to IP) as measured by
13
C nuclear magnetic resonance spectroscopy is determined according to the method of A. Zambelli, Macromolecules, 6, 925, 1973. That is, it refers to the isotacticity of the propylene-based polymer molecular chain in pentad units, as measured using nuclear magnetic resonance spectroscopy with isotopic carbon (
13
C-NMR). The IP according to the present invention is the measured value for the actual polypropylene obtained by polymerization, and is not the measured value for the polypropylene after the above mentioned xylene extraction or other extraction, separation, etc.
The classification of peaks was carried out based on the revised edition of the above document, as described in Macromolecules, 8, 687, 1975, and the IP was measured by the proportion of the strength of the mmmm peaks out of the total absorption peaks of the methyl carbons by
13
C-NMR spectroscopy.
The thus-measured IP of the propylene-based polymer must be 98.0% or greater, because if it is lower than this value the polymer will lack the desired rigidity, heat resistance, surface hardness, surface g
Itoh Kazuharu
Iwamoto Satoshi
Takahashi Hirotoshi
Watanabe Kazuyuki
Yanagihara Hisayoshi
Choi Ling-Siu
Showa Denko Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
Wu David W.
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