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
2002-07-19
2004-05-11
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...
C525S240000, C524S451000
Reexamination Certificate
active
06734253
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a coupled propylene polymer composition and fabricated articles thereof.
BACKGROUND OF THE INVENTION
Polypropylene has been used in many applications in the form of molded articles, film, sheet, etc., because it is excellent in molding processability, toughness, moisture resistance, gasoline resistance, chemical resistance, has a low specific gravity, and is inexpensive. The use of polypropylene polymers is expanding at an increasing rate in the fields of exterior and interior automotive trims, in electrical and electrical equipment device housing and covers as well as other household and personal articles.
However, many automotive applications require fabricated articles with greater heat resistance, impact resistance, stiffness and/or, especially for unpainted applications, scratch and mar resistance than conventional polypropylenes can provide. These deficiencies are obstacles to opening up new applications for polypropylene, particularly applications which have traditionally been injection molded.
Attempts to provide improved propylene polymer compositions include the use of a high crystalline propylene polymer, see U.S. Pat. No. 6,300,419, a unique metallocene catalyzed interpolymer and slip agent combination, see U.S. Pat. No. 6,329,454, or a unique combination of calcined and uncalcined tillers, see U.S. Pat. No. 6,403,692.
In order to improve performance, especially impact resistance, polypropylene has been blended with a rubbery elastic material such as ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber or ethylenebutene copolymer rubber. For examples, see U.S. Pat. No. 5,391,618 which discloses low crystalline polypropylene polymer compositions comprising an ethylene alpha-oletin copolymer, U.S. Pat. No. 5,576,374 which discloses propylene polymer compositions comprising a substantially linear ethylene polymer and U.S. Pat. No. 5,639,829 which discloses propylene polymer compositions comprising an ethylene and 1-butene random copolymer.
Attempts to modify the toughness of propylene polymers also include cross-linking or branching induced by non-selective chemistries involving free radicals using peroxides or high energy radiation. For the reaction of polypropylene with peroxides see Journal of Applied Polymer Science, Vol. 61, 1396-1404 (1996). However, this approach does not work well in actual practice as the rate of chain scission tends to dominate the limited amount of chain coupling that takes place. For radiation of polypropylene to produce long branches for producing polypropylene film see U.S. Pat. No. 5,414,027. Another method to improve melt strength of propylene polymers is taught in U.S. Pat. No. 3,336,268 wherein polypropylene is bridged with sulfonamide groups. However, while impact properties are improved, these propylene polymer compositions do not achieve a good balance of stiffness, toughness, and scratch and mar resistance.
It would be highly desirable to provide injection molded articles comprising a propylene polymer composition which exhibits a good balance of stiffness, toughness and scratch and mar resistance.
SUMMARY OF THE INVENTION
The present invention is a process for preparing an injection molding automotive article from a coupled propylene polymer composition comprising the steps of (i) preparing a coupled propylene polymer composition comprising (a) a propylene polymer formed by a reaction of from about 0.01 to about 1 weight percent of a poly(sultonyl azide) with a propylene polymer, wherein weight percent is based on the weight of the propylene polymer, and optionally one or more of (b) a polyolefin elastomer, (c) a thermoplastic polymer, (d) a filler or (e) a slip agent and (ii) injection molding an automotive article.
Another embodiment of the present invention is an injection molded automotive article comprising a coupled propylene polymer composition comprising a coupled propylene polymer formed by a reaction of from about 0.01 to about 1 weight percent of a poly(sulfonyl azide) with a propylene polymer and optionally one or more of a polyolefin elastomer, a thermoplastic polymer, a filler or a slip agent, weight percent based on the weight of the propylene polymer.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The injection molded automotive articles of the present invention are produced from a coupled propylene polymer composition. The coupled propylene polymer composition involves coupling of a propylene polymer using a coupling agent The propylene polymer Is a propylene homopolymer, preferably a propylene copolymer or most preferably an impact propylene copolymer.
The propylene polymer suitable for use in this invention is well known in the literature and can be prepared by vanous processes, for example, in a single stage or multiple stages, by such polymerization method as slurry polymerization, gas phase polymerization, bulk polymerization, solution polymerization or a combination thereof using a metallocene catalyst or a so-called Ziegler-Natta catalyst, which usually is one comprising a solid transition metal component comprising titanium. Particularly a catalyst consisting of, as a transition metal/solid component, a solid composition of titanium trichoride which contains as essential components titanium, magnesium and a halogen; as an organometalic component an organoaluminum compound; and it desired an electron donor. Preferred electron donors are organic compounds containing a nitrogen atom, a phosphorous atom, a sulfur atom, a silicon atom or a boron atom, and preferred are silicon compounds, ester compounds or ether compounds containing these atoms.
Propylene polymers are commonly made by catalytically reacting propylene in a polymerization reactor with appropriate molecular weight control agents. Nucleating agent is added after the reaction is completed in order to promote crystal formation. The polymerization catalyst should have high activity and be capable of generating highly lactic polymer. The reactor system must be capable of removing the heat of polymerization from the reaction mass, so the temperature and pressure of the reaction can be controlled appropriately.
A good discussion of various polypropylene polymers is contained in
Modem Plastics Encyclopedia
/89, mid October 1988 Issue, Volume 65, Number 11, pp. 86-92, the entire disclosure of which is incorporated herein by reference. In general, the propylene polymer is in the isotactic form, although other forms can also be used (e.g., syndiotactic or atactic). The propylene polymer used for the present invention is a propylene homopolymer or a propylene copolymer of propylene and an alpha-olefin, preferably a C
2
, or C
4
to C
20
alpha-olefin, for example, a random or block copolymer or preferably an impact propylene copolymer.
Examples of the C
2
, and C
4
to C
20
alpha-olefins for constituting the propylene copolymer include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene 4-methyl-1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 3,3dimethyl-1-butene, diethyl-1-butene, trimethyl-1-butene, 3-methyl-1-pentene, ethyl-1-pentene, propyl-1pentene, dimethyl-1-pentene, methylethyl-1-pentene, diethy-1-hexene, trimethyl-1 pentene, 3-methyl-1-hexene, dimethyl-1-hexene, 3,5,5trimethyl-1-hexene, methylethyl-1-heptene, trimethyl-1-heptene, dimethyloctene, ethyl-1-octene, methyl-1-nonene, vinylcyclopentene, vinylcyclohexene and vinylnorbomene, where alkyl branching position is not specified It Is generally on position 3 or higher of the alkene.
For random or block propylene copolymers, the alpha-olefin is present in an amount of not more than 15 weight percent, preferably not more than 12 weight percent, even more preferably not more than 9 weight percent and most preferably not more than 7 weight percent
Impact propylene copolymers are commercially available and are well known within the skill in the art for instance, as described by E. P. Moore, Jr in
Polvoropylene Handbook
, Hanser Publishers, 1996, page 220-221 and U.S. Pat. Nos. 3,893,989
Hovestad Neldes J.
Krabbenborg Franciscus J. T.
Dow Global Technologies Inc.
Nutter Nathan M.
LandOfFree
Scratch and mar resistant propylene polymer composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Scratch and mar resistant propylene polymer composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Scratch and mar resistant propylene polymer composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3251119