Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
1998-09-10
2001-05-29
Foelak, Morton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S140000
Reexamination Certificate
active
06239187
ABSTRACT:
The present invention relates to foams comprising cycloolefin copolymers.
It is known that polymeric materials can be foamed by addition of solid, liquid or gaseous blowing agents. Blowing agents used are solid substances such as azo compounds, liquid blowing agents such as hydrocarbons, halogenated hydrocarbons and gaseous blowing agents such as nitrogen, It is likewise known that polymers such as polystyrene and polyolefins (e.g. polyethylene, polypropylene) can be processed into foams having a variety of uses.
The advantage of polymeric foam materials is their lower density compared with the unfoamed starting material and also their insulating or damping properties dependent on material and processing. Said materials have a maximum long-term use temperature of up to 100° C. (Handbook of polymeric foams, editors D. Klempner, K. C. Frisch, Hanser Verlag 1991, Ullmann's Encyclopedia of Industrial Chemistry), so that they are not suitable for use at higher temperature.
To obtain materials having a higher heat distortion resistance together with simultaneouslygood chemical and hydrolysis resistance, polymerscomprising cycloolefins have therefore been proposed. DD Patent 223 157 describes rigid foams of norbornene-ethylene copolymers having a long-term heat distortion resistance up to 410 K and resistance toward hot aggressive aqueous media.
EP-A 384 693 likewise describes foams of polymers comprising cycloolefins. These include structures which are produced by ring-opening polymerizatien and ones which are obtained using a catalyst comprising a vanadium compound and an organoaluminum compound. The latter are copolymers of the cyclic olefin with ethene. In various examples, heat distortion resistance up to 115° C. was able to be confirmed.
EP-A 427 567 discloses polyolefins which are employed as support layer in a parabolic antenna and can be foamed. Polyrners having polar modificatiors can be prepared by polymerization using metallocene catalysts.
It is an object of the present invention to provide a foam which, when used in high-temperature applications and also in applications where high temperatures can occur for a comparatively short time, has higher heat distortion resistances together with simultaneously good mechanical properties. A further object of the present invention is to provide an environmentally friendly and economical process for producing a foam.
The object of the present invention is achieved by a foam comprising cycloolefin copolymers. The present invention provides a foam comprising at least one cycloolefin copolymer which comprises polymerized units derived from at least one cyclic, in particular polycyclic, olefin and, if desired, at least one acyclic olefin. The term cycloolefin copolymer includes both cycloolefin copolymers and also cycloolefin homopolymers.
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Patent Abstracts of Japan identified as JP 061-45408-A, 1994.
Hatke Wilfried
Helmer-Metzmann Freddy
Jacobs Alexandra
Foelak Morton
Frommer Lawrence & Haug
Ticona GmbH
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