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
1999-01-21
2003-01-28
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S205000, C525S206000, C525S207000, C525S218000, C525S220000, C525S221000, C525S285000, C525S326700, C525S327400, C525S327600, C525S328200, C525S328300, C525S340000, C525S343000, C525S354000, C525S355000, C525S379000, C525S382000, C525S384000, C525S386000
Reexamination Certificate
active
06512051
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to elastomer compositions including elastomers having functional groups, and compounds having additional functional groups. More particularly, the present invention pertains to elastomer compositions, in which functional groups of elastomers, and additional functional groups of compounds are capable of forming and cleaving cross-links reversibly with temperatures.
It is known, as described below, that an ionic bond, or a hydrogen bond is used for increasing a molecular weight of a monomer, or of a polymer, as well as modifying, or cross-linking the monomer or the polymer.
It was recently found that, when a polyallylamine and a long-chain alkyl acid are mixed, a salt is formed to generate a thermotropic liquid crystal. It was conceived that this phenomenon may have occurred, since the polyallylamine and the long-chain alkyl acid formed a salt within a range of temperature such that the salt would act as a methogen (Ujiie et al. Liquid crystal forum, 1997).
Onium salts with low molecular weights are widely used for preparation of, such as, an antistatic agent, an antimicrobial agent (JPA-9-111129), a gelling agent (JPB-2700377), a surface active agent (JPA-10-8041), a latent polymerization initiator (JPA-9-328507,JPB-2644301), and an energy ray-sensitive acid generator (JPA-9-202873). Moreover, polymeric compounds having onium salts, or their polymers are widely used for preparation of, such as, a pyridinium salt (JPA-9-324015), an ammonium salt (JPA-10-87741, JPB-2668260), a phosphonium salt-typed antimicrobial agent (JPA-10-81854), a monomer for soap-free polymerization (JPB-2668260), an antistatic agent (JPA-10-7822, JPA-9-328597), a film-forming perspiration-resistant polymer (JPA-10-500711), a water-soluble resin (JPB-2641955), a cross-linked polymeric ammonium salt (JPA-9-5007687), and a cleaner (JPA-9-235369).
However, a thermoplastic elastomer, in which a cross-link is formed by introducing an onium structure into a side chain of the elastomer, is not known. Moreover, an ionomer is known as a polymer having a cross-linked structure caused by a metallic ion.
It is a well-known fact that a hydrogen bond is formed between a carbonyl group and amine, and between pyridine and amine is seen in a biomolecule or the like. Immobilization of functional groups by hydrogen bonds is widely utilized in the ultramolecular-chemistry field, which is developing new functional molecules, such as an ion channel.
Moreover, it is also known that hydrogen bonds are utilized to modify thermoplastic resins. For example, JPA-63-69864 proposes a shape memory resin, which changes its shape by lowering the number of cross-links therein by heating it to over a grass transition point, but restores its original shape by cooling it to below the grass transition point. In JPA-63-69864, it is disclosed as a preferred embodiment that an epoxy compound and an amine curing agent are reacted to form a shape including a number of hydrogen bonds therein.
Furthermore, utilization of hydrogen bonds has been proposed to prevent heat resistance or rigidity from lowering, by adding a compound with a low molecular weight, or a thermoplastic resin with high flowability as a modifier. For example, a compound with a hydroxyl group, and a further compound with a functional group, which may form a hydrogen bond with the hydroxyl group of the former compound, are added into a thermoplastic resin such that flowability and heat resistance of the resin may be improved (JPA-5-339420). For an additional example, a thermoplastic resin, and a compound with a functional group, which may form a hydrogen bond with the following carboxyl group, are added to a styrene based resin having a carboxyl group such that rigidity and flowability of the styrene based resin may be improved (JPA-7-331002).
However, it is not known that a hydrogen bond is utilized for forming a cross-link between an elastomer and a compound.
Forming and cleaving of cross-links are known in polymer resins, but not known in elastomers. In other words, an elastomer having a conjugated diene structure including a heteroatom in its side chain is not known. It is also not known that, after a compound having more than two dienophiles, and an elastomer having a conjugated diene structure in its side chain are once bonded and cross-linked to each other by Diels-Alder reaction, the resultant cross-link is cleaved by heating.
Furthermore, an elastomer having a dienophile structure in its side chain is not known. It is also not known that, after the elastomer is once reacted with a compound having at least two conjugated dienes by Diels-Alder reaction to form a cross-link, which will then be cleaved by heating.
It is known that polyester having a furan moiety in its side chain is capable of cross-linking at 100° C. in the presence of bismaleimide, and capable of cleaving a resultant cross-link at 140° C. (U.S. Pat. No. 3,435,003). Moreover, the following two cases are also known (J. Polym. Sci., Polym. Chem. Ed. , 17 (1979) p. 2039, J. Polym. Sci., Polym. Chem. Ed., 17 (1979) p. 2055, U.S. Pat. No. 3,826,760 and U.S. Pat. No. 4,138,441):
After butyl rubber having cyclopentadiene is once cross-linked at room temperature, the butyl rubber will then be dissociated by heating in the presence of maleic anhydride; and
after ethylene-propylene rubber is once cross-linked at 150° C., the ethylene-propylene rubber will then be dissociated at 170° C.
Furthermore, it is known that a polymer having an oxazolidine or a furan shows a property of thermal cross-link formation and cleavage, which is capable of forming and cleaving cross-links reversibly with temperatures (Macromolecules, 1990, 23, p. 2636).
It is also known that, after resins having a furan skeleton react with bisdienophile to form a cross-link by Diels-Alder reaction, the cross-link will then be cleaved by heating (Macromolecules, 1998, 31, p. 2636).
Thermoplastic elastomers utilize physical cross-links, contrary to conventional vulcanized rubber having a stable three dimensional structure, in which a polymer and a vulcanizer form a covalent bond. The physical cross-links enable thermoplastic elastomers to be easily molded by the same fusion heating process as is applied to conventional thermoplastic resins. Therefore, it is not necessary that the thermoplastic elastomers employ a complicated vulcanizing and molding process including preforming.
As a typical example of such thermoplastic elastomers, a substance is known, which includes a resin component and a rubber component. At ordinary temperature, the resin component becomes a finely crystallized hard segment, which serves as a cross-link point of a three dimensional network structure. In this case, such hard segment prevents plastic deformation of the rubber component (soft segment) of the thermoplastic elastomers. However, as the temperature rises, the resin component is softened to melt. Then, the plastic deformation of the rubber component is allowed. Examples of such thermoplastic elastomers having a resin component and a rubber component are such as, for example, blockcopolymers such as a styrene-butadiene blockcopolymer, and an isoprene multiblockcopolymer, resin and rubber mixtures such as a mixture of polypropylene and ethylene-propylene dienecopolymer (EPDM). Moreover, a resin and rubber mixture, in which its rubber component (EPDM) is cross-linked by a peroxide, is also known.
Such thermoplastic elastomers, which have been known in the art, include a resin component as a hard segment such that rubber elasticity of the thermoplastic elastomers is undeniably lower than that of conventional vulcanized rubber. Accordingly, if a thermoplastic elastomer not including a resin component as a hard segment comes to be prepared, or, a vulcanized rubber comes to be provided with thermoplasticity properties (flowability), then, though a heat molding process without accompanying a complicated process of kneading, preforming, vulcanizing and the like, a rubber elastic body may simply be prepared. This will have a tr
Ashiura Makoto
Chino Keisuke
Ikawa Masahiro
Finnegan Henderson Farabow Garrett & Dunner LLP
Lipman Bernard
The Yokohama Rubber Co. Ltd.
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