Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-08-21
2002-05-21
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S128000, C528S172000, C528S173000, C528S176000, C528S183000, C528S185000, C528S220000, C528S229000, C528S353000, C528S125000, C343S7000MS, C343S785000, C343S91100R, C385S129000, C385S130000, C385S141000, C385S145000, C428S001100, C428S001260, C428S473500, C428S901000
Reexamination Certificate
active
06392004
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to gigahertz electronic devices containing elements composed of polyimides selected for their high polyimide equivalent weight.
BACKGROUND
U.S. Pat. Nos. 5,386,002, 3,758,434, 5,750,641, 5,969,088, 6,084,053 and 5,145,942 describes polyimides, some including polyimides derived from a fluorenyl diamine.
SUMMARY OF THE INVENTION
Briefly, the present invention provides an element of a gigahertz electronic device, i.e. a device for use with radiation or electronic signals in the 1-100 GHz frequency range, comprising a polyimide having an imide equivalent weight of 375 or greater. Such elements include circuit substrates, antennas and protective coatings. The polyimide preferably demonstrates a dielectric loss at 12.8 GHz of 0.009 or less. The polyimide preferably has a Tg of 260° C. or greater. The polyimide may be cured or crosslinked, as described in co-pending U.S. patent application Ser. No. 09/642,724, filed on even date herewith.
What has not been described in the art, and is provided by the present invention, is a means of enhancing electronic properties of polyimides in the 1-100 GHz frequency range by selecting polyimides of higher imide equivalent weight.
In this application:
“cured” describes a thermally treated polymer having less solubility at a given temperature than the same polymer prior to treatment, preferably measured in regard to solvents methyl ethyl ketone, N-methylpyrrolidone or &ggr;-butyrolactone and preferably at room temperature;
“crosslinked” describes a polymer having a network structure, typically demonstrated by insolublility even at elevated temperatures and for extended times;
“benzylic hydrogen” refers to a hydrogen atom attached to a carbon atom directly attached to an aromatic ring, e.g., any of the three methyl hydrogens of toluene, any of the two alpha hydrogens of ethyl benzene, etc.;
“polyimide” refers to a polyimide polymer unless indicated otherwise;
“a polyimide comprising a diamine” and like phrases should be understood to refer to polyimide polymers incorporating segments derived from the indicated diamine monomers, as by a polymerization including said monomers;
“diamines comprising pendent fluorenyl groups” refers to fluorenyl compounds disubstituted at the 9 position with amine-containing substituents, such as 9,9-bis(aminoaryl)fluorenes;
“polyimides comprising pendent fluorenyl groups” refers to polyimides derived at least in part from pendent-fluorenyl diamine monomers;
“C(number)” refers to a chemical moiety containing the indicated number of carbon atoms; and
the term “substituted” used without reference to a particular substituent means, for a chemical species, substituted by conventional substituents which do not interfere with the desired product or process, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, etc.
It is an advantage of the present invention to provide materials having good mechanical, optical and electrical characteristics of polyimides and additionally having improved gigahertz performance.
REFERENCES:
patent: 3758434 (1973-09-01), Kunzel et al.
patent: 5145937 (1992-09-01), Hergenrother et al.
patent: 5145942 (1992-09-01), Hergenrother et al.
patent: 5302692 (1994-04-01), St. Clair et al.
patent: 5386002 (1995-01-01), Inbasekaran et al.
patent: 5745984 (1998-05-01), Cole, Jr. et al.
patent: 5750641 (1998-05-01), Ezzell et al.
patent: 5969088 (1999-10-01), Ezzell et al.
patent: 6084053 (2000-07-01), Matsubara et al.
patent: 242815 (1987-10-01), None
patent: 0 592 002 (1994-04-01), None
patent: 0 875 906 (1998-11-01), None
patent: 5-31341 (1993-09-01), None
Derwent Acc-No: 1968-11052Q, Polyamides and Polyimides based on 9,9-bis 4aminophenylfluorene, Korshak, V.V., (Inst. of Hetero-Organic Sys.), -SU 198644A, 1968 the month in the date of publication is not available.
Chien Bert T.
Ezzell Stephen A.
3M Innovative Properties Company
Dahl Philip Y.
Hampton-Hightower P.
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