Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2000-04-26
2002-08-27
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C426S003000, C426S006000
Reexamination Certificate
active
06441126
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to crosslinked branched aliphatic polyesters that are biodegradable, a process for making them and their use as a chewing gum base.
BACKGROUND OF THE INVENTION
Aromatic polyesters such as poly (ethylene terephthalate) (PET), which are high melting and which have a high degree of cystallinity, are widely used in various molding and extrusion applications. Such applications include films, sheeting bottles, containers and the like. Aliphatic polyesters generally have low melting points and are therefore much less useful in typical industrial applications. However, it was recently reported that certain aliphatic polyesters based on monomers approved for food applications are useful as a chewing gum base. It would therefore be beneficial to provide for improved aliphatic polyesters for chewing gum bases and improved methods of making such material.
The preparation of polyesters is described in a recent book by George Odian,
Principles of Polymerization
, 2
nd
edition, pages 102-105 (1981), John Wiley & Sons, N.Y. Branched or crosslinked polymers can be prepared by using at least some monomers having a functionality of at least three. An apparatus for making such branched polymers is shown on page 132 of this same reference.
WO 98/17123 and WO 98/17124 patents to Wm. Wrigley Jr. Company describe a gum base including at least one aliphatic polyester that is produced from glycerol, propylene glycol or 1,3-butylene glycol and an aliphatic dibasic acid containing 4 to 12 carbon atoms.
JP 1038431A describes polyester resins for paint having narrow molecular weight distributions, prepared from aromatic acids such as phthalic acid, isophthalic acid, and terephthalic acid, or aliphatic acids such as maleic acid, adipic acid or azaelic acid with polyols such as glycerol, trimethylolpropane, ethylene glycol, 1,4-butanediol or 2,3-dimethyltrimethylene glycol in an inert solvent containing an esterification catalyst. An optional monobasic acid and/or monohydric alcohol could be added to the reaction mixture.
Nagata, M. et al.,
Reactional Functional Polymers
, Vol. 30, 165 (1996) describes the synthesis and enzymatic degradation of certain aliphatic polyesters based on glycerol and aliphatic dibasic acids containing 6 to 16 carbon atoms.
None of the above-cited references disclose a crosslinked branched aliphatic polyester chewing gum base, which is edible and biodegradable, and processes and formulations thereof. Thus, it is an object of the present invention to provide a crosslinked branched aliphatic polyester chewing gum base comprised of repeat units formed from at least one polyol, or ester thereof, at least one dibasic acid, or ester thereof, and at least one long chain monocarboxylic acid, or ester thereof. The gum bases are produced by reactive extrusion of a pre-gel.
SUMMARY OF THE INVENTION
The present invention provides for crosslinked branched aliphatic biodegradable chewing gum bases, formulations and processes thereof.
In one embodiment, the invention provides a gum base including at least one crosslinked branched aliphatic biodegradable polyester comprising repeat units formed from (1) at least one polyol having three to four hydroxy groups, or ester thereof, (2) at least one dibasic acid, or ester thereof, and (3) at least one long chain monocarboxylic acid, or ester thereof.
In another embodiment, the invention provides a process for making a crosslinked branched aliphatic biodegradable polyester comprising:
(a) reacting at least one polyol having from three to four hydroxy groups, or ester thereof, at least one dibasic acid, or ester thereof, and at least one long chain monocarboxylic acid, or ester thereof, at a sufficient temperature for a sufficient period to form a pre-gel;
(b) extruding the pre-gel at a sufficient temperature for a sufficient period, to convert the pre-gel to a crosslinked branched aliphatic biodegradable polyester.
In another embodiment, the invention provides a crosslinked branched aliphatic biodegradable polyester composition comprising (a) a polyester comprising repeat units formed from (1) at least one polyol having three to four hydroxy groups, or ester thereof, (2) at least one dibasic acid, or ester thereof; and (3) at least one long chain monocarboxylic acid, or ester thereof, and (b) greater than 0 to less than about 10 weight % based on the weight of the total composition of free long chain monocarboxylic acid.
In another embodiment, the invention provides a crosslinked branched aliphatic biodegradable polyester comprising repeat units formed from (1) at least one polyol having three to four hydroxy groups, or ester thereof, (2) at least one dibasic acid, or ester thereof, and (3) at least one long chain monocarboxylic acid, or ester thereof, wherein the crosslinked branched aliphatic biodegradable polyester has a molecular weight range of from about 100K to greater than about 1M.
In another embodiment, the invention provides a crosslinked branched aliphatic biodegradable polyester comprising repeat units formed from (1) at least one polyol having three to four hydroxy groups, or ester thereof, (2) at least one dibasic acid, or ester thereof; and (3) at least one long chain monocarboxylic acid, or ester thereof, wherein the crosslinked branched aliphatic biodegradable polyester has an acid value that is from about 100 to about 10,000.
In another embodiment, the invention provides a process for making a crosslinked branched aliphatic biodegradable polyester comprising:
(a) reacting at least one polyol having from three to four hydroxy groups, or ester thereof, and at least one dibasic acid, or ester thereof at a sufficient temperature for a sufficient period to form a pre-gel;
(b) extruding the pre-gel at a sufficient temperature for a sufficient period, to convert the pre-gel to a crosslinked branched aliphatic biodegradable polyester.
In another embodiment, the invention provides a chewing gum composition comprising the crosslinked branched aliphatic biodegradable polyester or gum base of the present invention.
Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
DETAILED DESCRIPTION OF THE INVENTION
The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the Examples included therein.
It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.
Ranges are often expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent about, it will be understood that the particular value forms another embodiment.
A weight percent of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included.
The molecular weight ranges expressed herein refer to the weight-average molecular weight.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. For example, the phrase “optionally substituted lower alkyl” means that the lower alkyl group may or may not be substituted and that the description includes both unsubsti
Cook Phillip M.
Staples John M.
Tomlinson Charles R.
Blake Esq. Michael J.
Eastman Chemical Company
Graves, Jr. Esq. Bernard J.
Michl Paul R.
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