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
2000-05-23
2002-03-19
Short, Patricia A. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S165000, C525S176000, C525S177000, C525S437000, C525S439000, C525S440030, C525S444000, C528S298000, C528S300000
Reexamination Certificate
active
06359070
ABSTRACT:
FIELD OF THE DISCLOSURE
This disclosure relates to polyester blends and methods of making polyester blends, and more specifically to polyesters containing an isosorbide moiety, blended with other thermoplastic polymers, and methods of making them.
BACKGROUND OF THE DISCLOSURE
The diol 1,4:3,6-dianhydro-D-sorbitol, referred to hereinafter as isosorbide, the structure of which is illustrated below, is readily made from renewable resources, such as sugars and starches. For example, isosorbide can be made from D-glucose by hydrogenation followed by acid-catalyzed dehydration.
Isosorbide has been incorporated as a monomer into polyesters that also include terephthaloyl moieties. See, for example, R. Storbeck et al.,
Makromol.Chem
., Vol. 194, pp. 53-64 (1993); R. Storbeck et al,
Polymer
, Vol. 34, p. 5003 (1993). However, it is generally believed that secondary alcohols such as isosorbide have poor reactivity and are sensitive to acid-catalyzed reactions. See, for example, D. Braun et al.,
J. Prakt.Chem
., Vol. 334, pp. 298-310 (1992). As a result of the poor reactivity, polyesters made with an isosorbide monomer and esters of terephthalic acid are expected to have a relatively low molecular weight. Ballauff et al, Polyesters (Derived from Renewable Sources), Polymeric Materials Encyclopedia, Vol. 8, p. 5892 (1996).
Copolymers containing isosorbide moieties, ethylene glycol moieties, and terephthaloyl moieties have been reported only rarely. A copolymer containing these three moieties, in which the mole ratio of ethylene glycol to isosorbide was about 90:10, was reported in published German Patent Application No. 1,263,981 (1968). The polymer was used as a minor component (about 10%) of a blend with polypropylene to improve the dyeability of polypropylene fiber. It was made by melt polymerization of dimethyl terephthalate, ethylene glycol, and isosorbide, but the conditions, which were described only in general terms in the publication, would not have given a polymer having a high molecular weight.
Copolymers of these same three monomers were described again recently, where it was observed that the glass transition temperature Tg of the copolymer increases with isosorbide monomer content up to about 200° C. for the isosorbide terephthalate homopolymer. The polymer samples were made by reacting terephthaloyl dichloride in solution with the diol monomers. This method yielded a copolymer with a molecular weight that is apparently higher than was obtained in the German Patent Application described above but still relatively low when compared against other polyester polymers and copolymers. Further, these polymers were made by solution polymerization and were thus free of diethylene glycol moieties as a product of polymerization. See R. Storbeck, Dissertation, Universitat Karlsruhe (1994); R. Storbeck, et al.,
J. Appl. Polymer Science
, Vol. 59, pp. 1199-1202 (1996).
U.S. Pat. No. 4,418,174 describes a process for the preparation of polyesters useful as raw materials in the production of aqueous stoving lacquers. The polyesters are prepared with an alcohol and an acid. One of the many preferred alcohols is dianhydrosorbitol. However, the average molecular weight of the polyesters is from 1,000 to 10,000, and no polyester actually containing a dianhydrosorbitol moiety was made.
U.S. Pat. No. 5,179,143 describes a process for the preparation of compression molded materials. Also, described therein are hydroxyl containing polyesters. These hydroxyl containing polyesters are listed to include polyhydric alcohols, including 1,4:3,6-dianhydrosorbitol. Again, however, the highest molecular weights reported are relatively low, i.e., 400 to 10,000, and no polyester actually containing the 1,4:3,6-dianhydrosorbitol moiety was made.
Published PCT Applications WO 97/14739 and WO 96/25449 describe cholesteric and nematic liquid crystalline polyesters that include isosorbide moieties as monomer units. Such polyesters have relatively low molecular weights and are not isotropic.
Currently, high molecular weight polyesters containing an isosorbide moiety have not been blended with other thermoplastic polymers.
SUMMARY OF THE DISCLOSURE
Contrary to the teachings and expectations that have been published in the prior art, isotropic, i.e., semi-crystalline and amorphous or non liquid crystalline, copolyesters containing terephthaloyl moieties, ethylene glycol moieties, isosorbide moieties and, optionally, diethylene glycol moieties are readily synthesized in molecular weights that are suitable for making fabricated products, such as films, beverage bottles, molded products, sheets and fibers on an industrial scale.
The polymers used, depend on the polymer composition that is desired. The amount of each polymer is desirably chosen so that the final polymeric product possesses the desired property.
The polyester desirably contains terephthaloyl moieties, ethylene glycol moieties, isosorbide moieties and, optionally, diethylene glycol moieties arranged to provide a useful high molecular weight polymer which may be blended with one or more of the thermoplastic polymers.
In a preferred embodiment, the number of terephthaloyl moieties in the polyester polymer is in the range of about 25% to about 50 mole % (mole % of the total polymer). The polyester polymer may also include amounts of one or more other aromatic diacid moieties such as, for example, those derived from isophthalic acid, 2,5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene-dicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 4,4′-bibenzoic acid, at combined levels up to about 25 mole % (mole % of the total polymer).
In a preferred embodiment, ethylene glycol monomer units are present in the polyester polymer in amounts of about 5 mole % to about 49.75 mole %. The polyester polymer may also contain diethylene glycol moieties. Depending on the method of manufacture, the amount of diethylene glycol moieties in the polyester polymer is in the range of about 0.0 mole % to about 25 mole %.
In a preferred embodiment, isosorbide is present in the polyester polymer in amounts in the range of about 0.25 mole % to about 40 mole %. One or more other diol monomer units may also be included in the polyester polymer in amounts up to a total of about 45 mole %.
Of course, all of the percentages are dependent on the particular application desired. Desirably, however, equimolar amounts of diacid monomer units and diol monomer units are present in the polyester polymer. This balance is desirable to achieve a high molecular weight polyester polymer.
The polyester polymer has an inherent viscosity, which is an indicator of molecular weight, of at least about 0.35 dL/g, as measured on a 1% (weight/volume) solution of the polymer in o-chlorophenol at a temperature of 25° C. This inherent viscosity is sufficient for some applications, such as some optical articles and coatings. For other applications, such as compact discs, an inherent viscosity of about 0.4 dL/g is preferred. Higher inherent viscosities, such as at least about 0.5 dL/g are needed for many other applications (e.g. bottles, films, sheet, molding resin). Further processing of the polyester polymer may achieve even higher inherent viscosities.
The polyester polymer is blended with one or more other thermoplastic polymers. The other thermoplastic polymers suitable for use in the blends of the present invention include polycarbonates; styrene resins; alkyl acrylate resins; polyurethanes; vinyl chloride polymers; polyarylethers; copolyetherester block polymers; polyhydroxyethers; polyarylates; other polyesters or mixtures thereof.
The ratio of polyester polymer to other thermoplastic polymer may vary widely depending on the desired properties.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE DISCLOSURE
The blends of the present invention are described below in terms of the polyesters and other thermoplastic polymers that may be included within the blends.
Polyester Polymers Containing Isosorbide Moieties
The polyester polymer, described in detail below, may be mad
Charbonneau Larry F.
Khanarian Garo
Witteler Helmut B.
Burns Doane , Swecker, Mathis LLP
E. I. du Pont Nemours and Company
Short Patricia A.
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