Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1997-12-22
2001-06-19
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S088000, C525S327600, C524S571000, C524S925000, C152S151000, C152S209120
Reexamination Certificate
active
06248827
ABSTRACT:
BACKGROUND OF THE INVENTION
The polymerization of styrene and maleic anhydride by free radical initiation well known in the prior art. Similarly, poly(styrene-co-maleic anhydride) and poly(styrene-alt-maleic anhydride) polymers are well known. Further, imidization between a maleic anhydride and a primary amine group is a commonly known chemical reaction. Publications which have recognized these reactions include: German Patent DE 4241538, assigned to Leuna-Werke A.-G; Japanese Patent JP 94248017, assigned to Monsanto Kasel Kk.; and, Italian Patent EP 322905 A2, assigned to Montedipe S.p.A. Various other non-patent publications have also recognized these reactions. Included among them are: L. E. Colleman, Jr., J. F. Bork, and H. Donn, Jr., J. Org. Chem., 24, 185(1959); A. Matsumoto, Y. Oki, and T. Otsu, Polymer J., 23(3),201(1991); L. Haeussler, U. Wienhold, V. Albricht, and S. Zschoche, Themochim. Acta, 277, 14(1966); W. Kim, and K. Seo, Macromol. Rapid Commun., 17, 835(1996); W. Lee, and G. Hwong, J. Appl. Polym. Sci., 59, 599(1996); and, I. Vermeesch and G. Groeninckx, J. Appl. Polym. Sci., 53, 1356(1994).
The synthesis of monofunctional N-alkyl and N-aryl maleimides are also well known in the prior art. They have been extensively used to improve the heat stability of homopolymers and especially copolymers prepared from vinyl monomers. Typically, the bulk resins comprise ABS (poly-(acrylonitrile-co-butadiene-co-styrene)) or a polyblend of poly-(acrylonitrile-co-butadiene) and poly-(styrene-co-acrylonitrile); PVC (poly(vinyl chloride)); SAN (poly(styrene-co-acrylonitrile)); PMMA (poly-(methyl methacrylate)); and the like. The maleimides can be copolymerized with other monomers such as acrylonitrile, butadiene, styrene, methyl methacrylate, vinyl chloride, vinyl acetate and many other comonomers. A more preferred practice in the industry is to produce copolymers of maleimides with other monomers such as styrene and optionally acrylonitrile and to blend these with ABS and SAN resins. In any event, the polymer compositions are adjusted so that the copolymers are fully compatible with the bulk resins (e.g., ABS and/or SAN) as shown by the presence of a single glass transition point (T
g
) as determined by differential scanning calorimetry (DSC).
It has long been recognized that two or more polymers may be blended together to form a wide variety of random or structured morphologies to obtain products that potentially offer desirable combinations of characteristics. However, it may be difficult or even impossible in practice to achieve many potential combinations through simple blending because of some inherent and fundamental problem. Frequently, the two polymers are thermodynamically immiscible, which precludes generating a truly homogeneous product. This immiscibility may not be a problem per se since often it is desirable to have a two-phase structure. However, the situation at the interface between these two phases very often does lead to problems. The typical case is one of high interfacial tension and poor adhesion between the two phases. This interfacial tension contributes, along with high viscosities, to the inherent difficulty of imparting the desired degree of dispersion to random mixtures and to their subsequent lack of stability, giving rise to gross separation or stratification during later processing or use. Poor adhesion leads, in part, to the very weak and brittle mechanical behavior often observed in dispersed blends and may render some highly structured morphologies impossible.
The abrasion resistance of rubbers generally increases with increasing molecular weight. However, viscosity of the unvulcanized rubber also increases with increase in molecular weight. Accordingly, in conventional practice a plasticizer (“extending oil”) is added to the unvulcanized rubber to lower its viscosity and to increase its workability to a point suitable for extrusion or other processing.
Kent et al in U.S. Pat. No. 3,528,936 and Cowperthwaite et al in U.S. Pat. No. 3,751,378 recognize that high molecular weight polymers of butadiene, etc., may be plasticized by addition of certain polyester monomers. Both patents teach admixture of the monomer and polymer together with an inorganic filler and other ingredients on an open mill or in an internal mixer, i.e., “dry” blending with a filler.
It is particularly desirable to prepare a polymer useful as an oil substitute that performs the function of a polymer extender or plasticizer while enhancing beneficial polymer properties such as tensile strength, maximum elongation, tear strength, damping properties.
OBJECTS OF THE INVENTION
It is an object of this invention to produce a poly(maleimide-co-alkenyl benzene) “centipede” polymer formed by imidizing a poly(alkenyl benzene-co-maleic anhydride). The “centipede” polymer has a high molecular weight spine connected with many relatively short side chains. The length of the main chain usually equals or is longer than the entanglement length, which is herein defined theoretically as an order of magnitude of 100 repeating units, while the length of the side chains is much smaller than the entanglement length.
Still more specifically, it is an object of the invention to provide a centipede polymer formed by imidizing a poly(styrene-co-maleic anhydride) with a primary amine to form a poly(maleimide-co-styrene) polymer.
It is a further object of the present invention to produce a high molecular weight poly(maleimide-co-alkenyl benzene) polymer formed by the reaction product of a maleic anhydride contributed monomer unit of a poly(alkyl benzene-co-maleic anhydride) and a primary amine containing from 1 to 50 carbon atoms in the alkyl and alkoxy substituents in the primary amine.
It is another object of the invention is to produce a high molecular weight poly(maleimide-co-alkenyl benzene) polymer useful as an oil substitute to be used as an a polymer extender that enhances beneficial polymer properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like.
Finally, it is yet another object of the invention is to produce a centipede polymer that exhibits improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like; that can be employed as a substitute for oils and/or plasticizers in the production of various other rubber compounds.
SUMMARY OF THE INVENTION
The present invention is broadly directed to poly(maleimide-co-alkenyl benzene) centipede polymer compositions formed by reacting a poly(alkenyl benzene-co-maleic anhydride) with a primary amine. It is further directed to a process for blending the poly(maleimide-co-alkenyl benzene) centipede polymer with elastomeric polymers, in combination with, or in substitution of, conventional extender oils, to produce extended polymers having improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is broadly directed to a polymer compositions of a poly(alkenyl benzene-co-maleimide) formed by reacting a poly(alkyl benzene-co-maleic anhydride) with a primary amine.
For the purposes of this invention, poly(alkenyl benzene-co-maleimide) and poly(alkyl benzene-co-maleic anhydride) are defined to encompass random and stereo-specific copolymers, including copolymers having alternating alkenyl benzene and maleimide or maleic anhydride contributed monomer units along the polymer backbone. Such alternating structure are typically described as poly(alkenyl benzene-adj-maleimide) and poly(alkyl benzene-adj-maleic anhydride), however, these polymers are encompassed herein within the descriptions poly(alkenyl benzene-co-maleimide) and poly(alkyl benzene-co-maleic anhydride)
Processes for forming poly(alkyl benzene-co-maleic anhydride) polymers are well known to those skilled in the art. The preparation of the copolymers from electron donor monomers, such as styrene, and electron acceptor monomers, such as maleic anhydride, as a result of complexation of the elec
Foltz Victor J.
Takeichi Hideo
Wang Xiaorong
Bridgestone Corporation
Burleson David G.
McCollister Scott A.
Yoon Tae H.
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