Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1993-04-28
1995-04-11
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
548521, 548545, C08F 832
Patent
active
054059186
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a new class of compounds, namely (poly)sulfide containing polycitraconimides and (poly)sulfide containing polyitaconimides. The invention also relates to a rubber composition having improved physical properties, which rubber composition is vulcanized with sulfur in the presence of one or more of the compounds of the present invention. The invention also relates to a sulfur-vulcanization process which is carried out in the presence of the particular compounds of the present invention and to the use of these compounds in the sulfur-vulcanization of rubber. Finally, the invention also relates to rubber products comprising rubber which has been vulcanized with sulfur in the presence of the compounds of the present invention.
Polycitraconimides and polyitaconimides are, in general, well known materials which may be prepared by the methods disclosed in, "The synthesis of Biscitraconimides and Polybiscitraconimides," Galanti, A.V. and Scola, D.A., Journ. of Polym. Sci.: Polymer Chemistry Edition, vol. 19, pp. 451-475, (1981); "The synthesis of Bisitaconamic Acids and Isomeric Bisimide Monomers," Galanti, A.V. et al., Journ. Polym. Sci.: Polymer Chemistry Edition, Vol. 20, pp. 233-239 (1982); and, Hartford, S.L., Subramanian, S. and Parker, J.A., Journ. Polym. Sci.: Polymer Chemistry Edition, Vol. 16, p. 137 (1982), the disclosures of which are hereby incorporated by reference.
In addition, some sulfur-containing imides are known from U.S. Pat. No. 3,974,163. In these imides, however, the sulfur is bonded directly to the imido nitrogen and thus, these materials behave in a significantly different manner than the imides of the present invention. Also disclosed in this patent is the use of these sulfur-containing imides as inhibitors of premature vulcanization of diene rubbers. However, the particular advantages of the compounds of the present invention are neither disclosed nor suggested by this publication. European patent application 345 825 also discloses sulfur-containing imides including N,N'-(thiodi-p-phenylene) bismaleimide, N,N'-(dithiodi-p-phenylene) bismaleimide, and N,N'-(sulfodi-pphenylene) bismaleimide. Also disclosed in this publication is the use of these imides in the vulcanization of rubber compositions with sulfur. However, this patent publication does not teach or suggest the sulfur-containing citraconimides of the present invention and the compounds of this publication are inferior to the present citraconimdes as sulfur-vulcanization coagents.
In the tire and belt industries, among others, better mechanical and heat resistance properties are being demanded. It has long been known that the mechanical properties of rubber can be improved by using a large amount of sulfur as a cross-linking agent to increase the cross-link density in vulcanized rubbers. However, the use of large amounts of sulfur suffers from the disadvantage that it produces reversion and leads to a marked decrease in heat resistance and resistance to flex cracking, among other properties, in the final product. The fact that reversion is a continuing problem can be seen from, "Rubber Microstructure and Reversion," Nordsiek, Dr. K.H., Rubber World, 197 (3), pp. 30-38, 1987, and, "Physikalische und Chemische Aspekte der Reversion," Kautschuk+Gummi--Kunstoffe, 34, No. 9, 1981.
In order to eliminate the foregoing disadvantage, it has been proposed to add coagents to sulfur-vulcanization systems. One known type of coagent are the maleimides. Such vulcanization systems are disclosed in, "Vulcanization With Maleimides," Journal of Applied Polymer Science, Vol. 8, pp. 2281-2298 (1964).
U.S. Pat. No. 3,297,713 suggests the use of dithiobis (N-phenylmaleimides) as vulcanizing agents for rubber. However, this system does not employ sulfur as a vulcanization agent and thus suffers from several disadvantages which result from the absence of sulfur cross-links in the rubber product.
Japanese patent publication J6 1014-238 discloses sulfur-vulcanization systems wherein maleimides are used as coagents and which also cont
REFERENCES:
patent: 3297713 (1967-01-01), Ladd
patent: 3920617 (1975-11-01), Hirosawa et al.
patent: 3974163 (1976-08-01), Coran et al.
patent: 4254229 (1981-03-01), Schwimdt et al.
Krashnennikov et al, High-temperature vulcanisation of unsaturated rubbers by thio derivatives of maleimide. Int'l Polymer Science & Technology, vol. 2 No. 6 1975, pp. 68-71.
Prashchikina et al. Influcence of the type and concentration of crosslinking agent on the effectiveness of a combined system of bismaleimide and sulphur. Intl'l Polymer Science and Technology, vol. 17, No. 11, 1990, pp. T/1-T/4.
Baker et al. Advances in natural rubber for tires: compounding for improved wear, Elastomerics, Jul. 1989, pp. 20-25.
Praschikina et al. High-Temperature curing of general-purpose rubbers with a curing system comprising a bismaleimideamd sulpur Int'l Polymer Science and Technology vol. 4 No. 12, 1977, pp. T/48-T/50.
Dr. Grunewald, Physikalische und chemische Aspekte der Reversion Kautschuk & Gummi Kunststoffe 34, Jahrgang, No. 9/81, pp. 722-724.
The Synthesis of Bisitaconamic Acids and Isomeric Bisimide Monomers Journal of Polymer Science: Polymer Chemistry Edition, vol. 20, 233-239 (1982) pp. 233-239.
Galanti et al. The Synthesis of Biscitraconimides and Polybiscitraconimides. Journal of Polymer Science: Polymer Chemistry Edition, vol. 19 (1981) pp. 452-474.
Hartford et al. Synthesis of N-Substituted bisitaconimide Monomers for Use as Thermosetting Polyimide Resins, Journal of Polymer Science: Polymer Chemistry Edition, vol. 16, 137-153 (1978).
Dr. K. H. Nordsiek, Rubber microstructure and reversion, Rubber World 197 (3), (1987) pp. 30-38.
P. O. Tawney et al. Vulcanization with maleimides. Journal of Applied Polymer Science vol. 8, 1964, pp. 2281-2298.
Chauchich, T. A. et al. Change in the structure and properties of vulcanizates based on natural, rubber under prolonged vulcanization in the presence of vulcanizing systems containing sulfur and bismaleimides. (USSR) Kauch, Rezina 1981, 95: 8561r.
Krasheninnikov et al. Vulcanization of cis -1,4-isoprene rubber by derivatives of maleimide under the action of high temperatures and radiation. International Polymer Science and Technology, vol. 1, No. 5, 1974. pp. T/57-T/59.
de Block Rudolf F.
Hogt Andreas H.
Talma Auke G.
Akzo Nobel N.V.
Cain Edward
Mancini Ralph J.
Michl Paul R.
Morris Louis A.
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