Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1990-08-22
1992-12-29
Anderson, Harold D.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
524548, 528170, 528321, 528322, C08F 2240
Patent
active
051752247
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to diamines and bismaleimides, and to 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 employed.
However, an essential disadvantage of these known polyimides is that they are brittle, are difficult to melt and are sparingly soluble, so that they can be further processed only with difficulty and only to a limited degree. For example, no films or foils but only rigid laminates can be produced from them.
The object of the invention was therefore to discover diamines and bismaleimides which can be polymerized to give flexible, less brittle polyimides which can be shaped by means of heat and which can easily be further processed in subsequent operations, for example during impregnation of woven fibers or fiber mats or by compression molding.
The object was achieved with the aid of novel diamines and bismaleimides which contain a thiazole, thiadiazole or triazole ring bonded by ether or thioether groups in their chain and from which it has been possible to prepare improved polyimides.
The present invention accordingly relates to diamines and bismaleimides of the general formula I ##STR2## in which R.sub.1 and R.sub.2 denote an H atom or together denote the group --OC--CH.dbd.CH--CO--, Y.sub.1 and Y.sub.2 independently of one another denote O or S and Het denotes a thiazole, thiadiazole or 1-methyltriazole ring. Compounds in which Y.sub.1 and Y.sub.2 are identical are preferred.
In the case where R.sub.1 and R.sub.2 denote an H atom, the chemical compounds according to the invention are aromatic diamines, and in the case where R.sub.1 and R.sub.2 together denote the group --OC--CH.dbd.CH--CO--, the chemical compounds according to the invention are aromatic bismaleimides.
The substances according to the invention are prepared by reaction of dimercapto- or dihydroxy-heterocyclic compounds, preferably in the form of their alkali metal salts, of the general formula II: chloroaniline, NaCl or KCl being split off to give the diamine according to the invention, of the general formula I. It is also possible for the compounds of the general formula II to be reacted with p-chloronitrobenzene, NaCl or KCl first being split off to give the corresponding dinitro compounds, which are then reduced by means of hydrogen to give the diamine according to the invention. The bismaleimides according to the invention, of the general formula I are obtained by reaction of the diamines according to the invention, of the general formula I, with maleic acid or derivatives thereof, for example with maleic anhydride.
The starting compounds according to the formula II are prepared by known processes, for example in accordance with DE-C-958,650 and DE-A-2,360,623, in accordance with J. V. Metzger "Thiazole and its derivatives", Chemistry of Heterocyclic Compounds, Volume 34, Part 1 (1979) page 215, J. Wiley, New York or in accordance with Frank F. Cesark (Northwestern Univ., Evanston, Ill.). Univ. Microfilms (Ann Arbor, Mich.), Order No. 61-5299, 101 pp.; Dissertation Abstr. 22,2192 (1962).
The diamines and bismaleimides according to the invention can be used for the preparation of polyimides having improved properties. The bismaleimides can be polymerized either by themselves or together with the diamines to give polyimides.
The invention furthermore relates to the polyimides prepared from the diamines and bismaleimides according to the invention. The polyimides consist of recurring monomeric units of compounds according to the formula I, the polymer bond being established via the double bonds of the maleimide radicals in the case where bismaleimides are used by themselves, and an addition of the NH.sub.2 groups of the diamine onto the double bond of the maleimide radical also taking
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Anderson Harold D.
Petrochemie Danubia Gesellschaft m.b.H.
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