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
2000-09-29
2002-04-09
Cain, Edward J. (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...
Reexamination Certificate
active
06369166
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the use of alkylmaleimide copolymers as additives in rubber compounds to improve tensile and tear strengths and damping properties.
BACKGROUND OF THE INVENTION
Poly(isobutylene-co-maleic anhydride) polymer is commercially available and is well known in the prior art. Further, imidization between a maleic anhydride and a primary amine group is a commonly known chemical reaction. Patent 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 homo- 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 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.
It is particularly desirable to increase the tensile strength and tear strength in rubber compounds. It is particularly desirable to prepare a copolymer 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 and damping properties.
OBJECTS OF THE INVENTION
Accordingly, it is an object of this invention to provide a poly(disubstituted-ethylene-co-maleimide) that is useful as a plasticizer or 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 blend of an elastomer and a poly(disubstituted-ethylene-co-maleimide) copolymer that exhibits improved properties such as tensile strength, maximum elongation, tear strength, damping properties, and the like versus oil extended elastomers.
SUMMARY OF THE INVENTION
The present invention is directed to the use of poly(disubstituted-ethylene-co-maleimide) copolymers to extend or plasticize rubbers to improve the tensile strength, tear strength and damping properties of the modified rubber.
The present invention is broadly directed to copolymer compositions of a poly(disubstituted-ethylene-co-maleic anhydride) reacted with an amine.
DETAILED DESCRIPTION OF THE INVENTION
The extended elastomeric polymer of the present invention contains: 100 parts by weight of a solid elastomeric polymer such as a thermodynamically miscible elastomeric polymer or copolymer; and 0.5-200 parts by weight of a poly(R
1
(R
2
)ethylene-co-maleimide) copolymer placticizer, wherein R
1
and R
2
are the same or different substituents on the same &agr;-carbon atom of the ethylene group selected from the group consisting of unsubstituted and substituted C
1
to C
20
alkyl groups, the substituted groups being non-reactive with the remaining components of the centipede polymers such as alkoxyalkyl groups having C
2
to C
20
atoms.
The poly(R
1
(R
2
)ethylene-co-maleimide) is a “centipede” polymer formed by imidizing a poly(R
1
(R
2
)ethylene-co-maleic anhydride) with a primary amine. The “centipede” polymer has a high molecular weight spine connected with many relatively short side chains formed from the addition of the primary amines. 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.
The R
1
(R
2
)ethylene contributed monomer units of the poly(R
1
(R
2
)ethylene-co-maleimide) “centipede” polymer contain 4 to about 40 carbon atoms wherein R
1
and R
2
are the same or different substituents on the same &agr;-carbon atom of the ethylene group selected from the group consisting of unsubstituted and substituted C
1
to C
20
alkyl groups, the substituted groups, such as alkoxyalkyl groups having C
2
to C
20
atoms, being non-reactive with the remaining components of the centipede polymers. Examples of unsubstituted and substituted alkyl groups R
1
and R
2
in the R
1
(R
2
)ethylene contributed monomer units are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, cyclopropyl, 2,2-dimethylcyclopropyl, cyclopentyl, cyclohexyl, methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, ethoxybutyl, ethoxypentyl, ethoxyhexyl, ethoxyheptyl, ethoxyoctyl, ethoxynonyl, ethoxydecyl, propoxymethyl, propoxyethyl, propoxypropyl, propoxybutyl, propoxypentyl, propoxyhexyl, propoxyheptyl, propoxyoctyl, propoxynonyl, propoxydecyl, butoxybutoxymethyl, butoxyethyl, butoxypropyl, butoxybutyl, butoxypentyl, butoxyhexyl, butoxyheptyl, butoxyoctyl, butoxynonyl, butoxydecyl, pentyloxymethyl, pentyloxyethyl, pentyloxypropyl, pentyloxybutyl, pentyloxypentyl, pentyloxyhexyl, pentyloxyoctyl, pentyloxynonyl, pentyloxydecyl, hexyloxymethyl, hexyloxyethyl, hexyloxypropyl, hexyloxybutyl, hexyloxypentyl, hexyloxyhexyl, hexyloxyheptyl, hexyloxyoctyl, hexyloxynonyl, hexyloxydecyl, heptyloxymethyl, heptyloxyethyl, heptylox
Foltz Victor J.
Wang Xiaorong
Bridgestone Corporation
Burleson David G.
Cain Edward J.
McCollister Scott A.
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