Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1990-04-24
1992-07-14
Springer, David B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
528353, 528337, 528336, C07D207452, C08G 7312
Patent
active
051304449
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to bismaleimides and optionally fiber-reinforced polyimides prepared therefrom.
Polyimides based on bismaleimides are already known from U.S. Pat. No. 3,380,964, and they can be prepared by heating the bismaleimides at temperatures of 80.degree. to 400.degree. C., ethylene-bis-maleimide, diphenylmethane-bis-maleimide, diphenyl ether-bis-maleimide or diphenyl sulfone-bis-maleimide, inter alia, being used.
The known polyimides are distinguished by a heat stability which is very high for plastics. However, they have the disadvantage that they are very brittle and can be further processed only to a limited degree. For example, only hard and brittle laminates can be produced from them.
The object of the invention was therefore to discover dismaleimides which can be polymerized to flexible and less brittle polyimides which are optionally reinforced with fibers and if appropriate can be brought into the final shape by subsequent compression molding.
The object of the invention has been achieved with the aid of novel bismaleimides which contain aromatics as chain elements bonded via --S-- and --SOhd 2-- bridges and from which polyimides with improved properties can be prepared.
The invention accordingly relates to bismaleimides of the formula I as follows ##STR3## in which R denotes a radical of the formula II as follows ##STR4##
The bismaleimides according to the invention are prepared by reacting the diamine of the formula III as follows the formula III well in polar solvents, such as, for example, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone (NMP), tetramethylurea or hexamethylphosphoric acid triamide.
The diamine of the formula III, 1,4-bis-(4-aminophenylthio)diphenyl sulfone (BDS) is obtained, for example, in accordance with ER-A-0,245,815 by reaction of the Na salt of bis-(4-mercaptophenyl)diphenyl sulfone with excess 4-chloronitrobenzene to give 1,4-bis-(4-nitrophenylthio)diphenyl sulfone and subsequent reduction of the nitro groups.
The bismaleimides according to the invention can be used for the preparation of polyimides with improved properties. The bismaleimides can be polymerized either by themselves or together with an aromatic diamine to give polyimides. Possible aromatic diamines are all the diamines known in polyamide and polyimide chemistry. Suitable diamines are, for example, those based on aromatic, fused aromatic or heteroaromatic rings, which are optionally further substituted, for example by alkyl or alkoxy groups or by halogen atoms. The diamine can be built up from either one or more rings, the rings being bonded to one another directly or via bridge members. Examples of suitable bridge members are --O--, --CH.sub.2 --, --C(CH.sub.3).sub.2, --C(CF.sub.3).sub.2 --, --S--, --SO--, --SO.sub.2 --, --CO--, --CO--O--, --CO--NH--, --N.dbd.--, --NH--, --N(alkyl)-- having 1 to 6 C atoms in the alkyl radical and --N(aryl)-- having 6 to 20 C atoms in the aryl radical.
Examples of possible aromatic diamines are: 1,4-phenylenediamine, 4,4'-diaminodiphenyl, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-methylenebis(o-chloroaniline), 1,2-bis(2-aminophenylthio) propane, diisopropyl methylenedianthranilate, 4,4'-methylene-bis-2,6-diisopropylaniline, propyl 3,5-diamino-4-chlorobenzoate, 4,4'-diamino-5,5'-dimethylphenyl-2,2'-disulfonic acid, 5(6)-amino-1l-(4-aminophenyl)-1,3,3-trimethylindane, 5,5'-diamino-2,2'-bipyridyl sulfide, 2,4-diethyltoluidinediamine, 4,4'-diaminobisbenzophenone, dioxyphenylenebisaminopyridine and 2,5-diamino-1,3,4-thiadiazole.
The diamine of the formula III
The invention furthermore relates to the polyimides prepared from the bismaleimides according to the invention. The polyimides consist of recurring monomeric units of bismaleimides of the formula IV ##STR5## the polymer bond being via the double bonds of the maleimide radicals where bismaleimides are used, and addition of the NH.sub.2 groups of the diamine onto the double bond of the maleimide
REFERENCES:
patent: 4128598 (1978-12-01), Makino et al.
patent: 4759987 (1988-07-01), Mizobe et al.
Kwiatkowski et al., Journal of Polymer Science, Poly. Chem. Ed., 13, 961-972 (1975).
A. Harvey, Hochmolekularbericht 1987, H.4082/87, Reg. of Annu. Tech. Conf. Soc. Plast. Eng. 32, 1311-1315 (1986)--Abstract.
Greber Gerd
Horacek Heinz
PCD Polymere Gesellschaft m.b.H.
Springer David B.
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