Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From ketone or ketene reactant
Reexamination Certificate
2005-12-13
2005-12-13
Berman, Susan (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From ketone or ketene reactant
C528S220000, C522S167000
Reexamination Certificate
active
06974855
ABSTRACT:
The novel polyimides of this invention are derived from Diels-Alder cyclopolymerization of photochemically generated bisdienes with dienophiles, such as bismaleimides, trismaleimides and mixtures thereof with maleimide end-caps. Irradiation of one or more diketones produces two distinct hydroxy o-quinodimethane (photoenol) intermediates. These intermediates are trapped via Diels-Alder cycloaddition with appropriate dienophiles, e.g., bismaleimide and/or trismaleimides to give the corresponding polyimides in quantitative yields. When bismaleimides, trismaleimides or mixtures thereof with maleimide end-caps are used as the dienophile, the resulting polyimides have glass transition temperatures (Tg) as high as 300° C. Polyimide films can be prepared by ultraviolet irradiation of high solids content varnishes of the monomers in a small amount of solvent, e.g., cyclohexanone, dimethyl formamide, N-methylpyrollidone and the like. These novel polyimides are characterized as having high glass transition temperatures, good mechanical properties and improved processing in the manufacture of adhesives, electronic materials and films.
REFERENCES:
patent: 6140385 (2000-10-01), Bowers et al.
patent: 6153662 (2000-11-01), Miller et al.
patent: 6593389 (2003-07-01), Meador
Macromolecules vol. 29, No. 27, pp. 8983-8986.
NASA News, Sampe Jour. vol. 36, No. 5, Sep. 2000, Jones et al, “Curable Polyimides . . . ”.
Lewis Research Ctr, “Room Temperature Ultraviolet Curing of Polyimides”, NASA Tech Briefs, Mar. 1999.
Berman Susan
Stone Kent N.
The United States of America as represented by the Administrator
Tura James V.
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