Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1999-06-14
2001-07-03
Short, Patricia A. (Department: 1712)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S035700, C525S437000, C525S444000, C525S448000
Reexamination Certificate
active
06254950
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to polyester compositions that possess improved gas barrier properties. The novel copolyester blends comprise repeat units of phenylyenedi(oxyacetic acid). Such copolyesters with improved gas barrier properties are useful in packaging applications where low gas permeability are required for protection or preservation of the contents.
BACKGROUND OF THE INVENTION
Phenylenedi(oxyacetic acid) can be prepared by several methods. U.S. Pat. Nos. 4,238,625 and 4,935,540 describe one method of preparing phenylenedi(oxyacetic acid) through the oxidation of aryloxyethanols. JP 3204833, JP 4091052 and JP 4173765 describe the preparation of phenylenedi(oxyacetic acid) from resorcinol and chloroacetic acid.
U.S. Pat. No. 4,440,922 describes the polyester homopolymers made from phenylenedi(oxyacetic acid). However, homopolymers made from phenylenedi(oxyacetic acid) are amorphous and have low glass transition temperatures making these polyesters difficult to dry. They polyesters have low elongations and are consequently brittle. In general, homopolymers made from phenylenedi(oxyacetic acid) are unsuitable for use in rigid containers.
U.S. Pat. Nos. 4,440,922, 4,552,948, 4,663,426, and 5,030,705 describe the use of copolyesters containing phenylenedi(oxyacetic acid) for containers. These copolyesters have low permeability. However, because of the high level of modification, these copolyesters are difficult to crystallize. The poor crystallization behavior of these copolyesters makes them difficult to dry and limits the amount of strain induced crystallization that occurs during container fabrication. Low levels of crystallinity in the containers often result in poorer mechanical properties and lower gas barrier.
U.S. Pat. No. 5,239,045 describes copolyesters containing terephthalic acid, ethylene glycol and 0.5 to 4.5 mole % of phenylenedi(oxyacetic acid). The gas barrier properties of these copolyesters are not sufficient to meet the requirements of many container applications including beer and small soft drink containers.
U.S. Pat. No. 4,959,421 describes blends of PET with copolyesters containing isophthalic acid, naphthalenedicarboxylic acid and phenylenedi(oxyacetic acid). In these gas barrier materials disclosed in the above-described specification, however, the barrier level is low and in order to produce a container having a sufficient gas barrier property, it is necessary to make the barrier layer thick. The total thickness of the container is, therefore, inconveniently increased. In addition, the copolyesters in the above-described specification are immiscible with PET; thus, blends of the copolyesters with PET can be hazy which is undesirable in many container applications.
The above-mentioned prior art polyesters and copolyesters comprising phenylenedi(oxyacetic acid) exhibit poor crystallinity and gas barrier properties. The present invention overcomes the problems of poor crystallization and/or gas barrier properties by providing a novel copolyester blend containing phenylenedi(oxyacetic acid) with improved gas barrier properties.
SUMMARY OF THE INVENTION
The present invention provides for copolyester blend compositions, methods of making, and articles of manufacture thereof.
In one embodiment, the invention provides polyester blends comprising:
I. from about 5 to about 85 weight % of a copolyester which is the reaction product of components comprising:
(A) a repeat unit of a dicarboxylic acid component comprising
(i) from about 5 to about 99 mole % of a phenylenedi(oxyacetic acid) represented by the formula (I):
wherein R
1
,R
2
,R
3
and R
4
each independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a phenyl group, a chlorine atom, a bromine atom, or a fluorine atom, or an ester derivative of phenylendi(oxayacetic acid) of the formula I;
(ii) from about 1 to about 95 mole % of a repeat unit of a second diacid comprising terephthalic acid, isophththalic acid, naphthalenedicarboxylic, or cyclohexanedicarboxylic acid, or ester thereof, or mixture thereof; and
(B) a repeat unit of a diol containing up to 24 carbon atoms; and
I. from about 95 to about 15 weight % of a thermoplastic polyester of poly(ethylene terephthalate), a copolyester of poly(ethylene terephthalate) modified with from greater than 0 to about 70 mole % of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol or 1,4-cyclohexanedimethanol, and/or a dicarboxylic acid comprising isophthalic acid or naphthalenedicarboxylic acid, or a mixture of the poly(ethylene terephthalate) copolyester with poly(ethylene terephthalate);
from about 95 to about 15 weight % of a polyester of poly(ethylene naphthalate), a copolyester of poly(ethylene naphthalate) modified with from greater than 0 to about 30 mole % a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol or 1,4-cyclohexanedimethanol, and/or a dicarboxylic acid comprising isophthalic acid or terephthalic acid, or a mixture of the poly(ethylene naphthalate) copolyester with poly(ethylene naphthalate);
from about 95 to about 15% weight of poly(butylene terephthalate);
from about 95 to about 15 weight % of poly(trimethylene terephthalate); or
from about 95 to about 15% weight % of poly(butylene naphthalate).
In another embodiment, the invention provides a method of producing a polyester blend comprising:
blending from about 5 to about 85 weight % of a copolyester I and from about 95 to about 15 weight % of polyester II, wherein polyester I comprises:
(A) a repeat unit of from about 5 to 99 mole % of phenylenedi(oxyacetic acid) represented by the formula (I):
wherein R
1
,R
2
,R
3
and R
4
each independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a phenyl group, a chlorine atom, a bromine atom, or a fluorine atom, or an ester derivative of phenylenedi(oxyacetic acid) of the formula I;
(ii) from about 1 to about 95 mole % of a repeat unit of a second diacid comprising terephthalic acid, isophththalic acid, naphthalenedicarboxylic acid, or cyclohexanedicarboxylic acid, or ester thereof, or mixture thereof; and
(B) a repeat unit of a diol containing up to 24 carbon atoms; and
polyester II comprises a thermoplastic polyester of poly(ethylene terephthalate), a copolyester of poly(ethylene terephthalate) modified with from greater than 0 to about 70 mole % of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol or 1,4-cyclohexanedimethanol, and/or a dicarboxylic acid comprising isophthalic acid or naphthalenedicarboxylic acid, or a mixture of the poly(ethylene terephthalate) copolyester with poly(ethylene terephthalate);
a polyester of poly(ethylene naphthalate), a copolyester of poly(ethylene naphthalate) modified with from greater than 0 to about 30 mole % of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol, or 1,4-cyclohexanedimethanol, and/or a dicarboxcylic acid comprising isophthalic acid or terephthalic acid, or a mixture of the poly(ethylene naphthalate) copolyester with poly(ethylene naphthalate);
a poly(butylene terephthalate);
a poly(trimethylene terephthalate); or
a poly(butylene naphthalate).
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 therein.
It must be noted that, as used i
Barbee Robert B.
Fagerburg David R.
Long Timothy E.
Rogers Martin E.
Eastman Chemical Company
Graves, Jr. Bernard J.
Harding Karen A.
Short Patricia A.
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