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
2000-08-14
2001-11-27
Reddick, Judy M. (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...
C525S330600
Reexamination Certificate
active
06323288
ABSTRACT:
FIELD OF THE INVENTION
The invention comprises compositions having an ethylenic or polyethylenic backbone that are useful in packaging or adhesives applications. This invention also provides compositions having an ethylenic or polyethylenic backbone that are useful in scavenging oxygen from packaged products. The invention also comprises a process for esterification and/or transesterification of a compound having acid and/or ester side chains on an ethylenic or polyethylenic backbone to produce a compound having a different number and/or type of ester side-chain on the ethylenic or polyethylenic backbone.
BACKGROUND AND SUMMARY OF THE INVENTION
New polymer compositions having properties that are particularly tailored for specific applications are required in response to more sophisticated purchasers of polymers. It is extremely costly and/or difficult to make these compositions directly by synthesis or via solution esterification or transesterification, but manufacturing them in mixing equipment such as an extruder has provided an economical and viable means to supply increasingly-complex polymers to specialized markets requiring them.
In one embodiment, this invention provides specialty polymers whose compositions have a polyethylenic backbone and pendant benzyl ester moieties. In another embodiment, this invention provides compositions having a polyethylenic backbone and pendant hydrocarbyl ester moieties that contain at least one allylic hydrogen. In a further embodiment, this invention provides compositions having a polyethylenic backbone and pendant hydrocarbyl moieties, especially hydrocarbyl ester moieties, wherein the hyrocarbyl group contains a heteroatom such as oxygen. In a preferred embodiment, this invention provides compositions having a polyethylenic backbone and pendant ether ester moieties, especially cyclic ether ester moieties.
In certain preferred embodiments, the compositions of this invention have the following structures:
where n is an integer from 2 to approximately 30,000; any X is individually chosen from the group consisting of hydrogen and methyl radical; and where any Y is individually chosen from the group consisting of hydrogen, alkyl radicals containing from 1 to 18 carbon atoms, alkoxy radicals having from 1 to 16 carbon atoms, alkyl ether radicals having from 2 to 18 carbon atoms, alkenyl and alkynyl radicals containing from 2 to 18 carbon atoms, alkenoxy and alkynoxy radicals having from 2 to 16 carbon atoms, alkenyl and alkynyl ether radicals having from 3 to 18 carbon atoms, amine radicals having from 1 to 16 carbon atoms, acid and metal salt of acid radicals, anhydride radicals having from 4 to 24 carbon atoms, ester and amide radicals of acids having from 1 to 16 carbon atoms, aryl radicals and substituted aryl radicals having 6 to 24 carbon atoms, aryl ether radicals and substituted aryl ether radicals having from 6 to 24 carbon atoms, and the radicals of Formula II and Formula III
where any A is individually a heteroatom-containing radical (especially a carboxy or amido), and where any B is individually chosen from the group consisting of alkyl ether radicals having from 2 to 18 carbon atoms, alkenyl and alkynyl radicals containing from 2 to 18 carbon atoms, alkenoxy and alkynoxy radicals having from 2 to 16 carbon atoms, alkenyl and alkynyl ether radicals having from 3 to 18 carbon atoms, substituted aryl radicals having 6 to 24 carbon atoms, aryl ether radicals and substituted aryl ether radicals having from 6 to 24 carbon atoms, and the radicals of Formula IV and Formula V:
where any R
1
, R
2
, R
3
, R
4
, R
5
, and R
6
is individually chosen from the group consisting of hydrogen, alkyl radicals containing from 1 to 18 carbon atoms, alkoxy radicals having from 1 to 16 carbon atoms, amine radicals having from 1 to 6 carbon atoms, ester and amide radicals of acids having from 1 to 16 carbon atoms, aryl radicals and substituted aryl radicals having 6 to 24 carbon atoms, aryl ether radicals and substituted aryl ether radicals having from 6 to 24 carbon atoms, and the radicals of Formula II and Formula III; with the proviso that at least about 1 mole % of the composition comprises the radicals of Formula II and Formula III.
These specialty polymers are useful as packaging films and are also useful components for making oxygen-scavenging compositions.
This invention also provides new oxygen-scavenging compositions. It is well known that regulating the exposure of oxygen-sensitive products to oxygen maintains and enhances the quality and “shelf-life” of the product. For instance, by limiting the exposure of oxygen sensitive food products to oxygen in a packaging system, the quality or freshness of food is maintained, and the food doesn't spoil as rapidly. In addition, oxygen-scavenging packaging also keeps the product in inventory longer, thereby reducing costs incurred from waste and having to restock inventory. In the food packaging industry, several means for regulating oxygen exposure have already been developed. These means include modified atmosphere packaging (MAP) and oxygen barrier film packaging.
One method currently being used is through “active packaging”, whereby the package containing the food product has been modified in some manner to regulate the food's exposure to oxygen. One form of active packaging uses oxygen-scavenging sachets which contain a composition which scavenges the oxygen through oxidation reactions. One type of sachet contains iron-based compositions which oxidize to their ferric states. Another type of sachet contains unsaturated fatty acid salts on a particulate adsorbent. See U.S. Pat. No. 4,908,151. Yet another sachet contains metal/polyamide complex. See U.S. Pat. No. 5,194,478.
However, one disadvantage of sachets is the need for additional packaging operations to add the sachet to each package. A further disadvantage arising from the iron-based sachets is that certain atmospheric conditions (e.g., high humidity, low CO
2
level) in the package are sometimes required in order for scavenging to occur at an adequate rate. Further, the sachets can present a danger to consumers if accidentally ingested.
Another means for regulating exposure of a packaged product to oxygen involves incorporating an oxygen scavenger into the packaging structure itself. A more uniform scavenging effect throughout the package is achieved by incorporating the scavenging material in the package instead of adding a separate scavenger structure (e.g., a sachet) to the package. This may be especially important where there is restricted air flow inside the package. In addition, incorporating the oxygen scavenger into the package structure provides a means of intercepting and scavenging oxygen as it permeates the walls of the package (herein referred to as an “active oxygen barrier”), thereby maintaining the lowest possible oxygen level in the package.
One attempt to prepare an oxygen-scavenging wall involves the incorporation of inorganic powders and/or salts. See U.S. Pat. Nos. 5,153,038, 5,116,660, 5,143,769, and 5,089,323. However, incorporation of these powders and/or salts causes degradation of the wall's transparency and mechanical properties such as tear strength. In addition, these compounds can lead to processing difficulties, especially when fabricating thin films. The oxidation products, which can be absorbed by food in the container, typically would not have FDA approval for human consumption.
EP 0 519 616 discloses an oxygen-scavenging composition comprising a blend of a first polymeric component comprising a polyolefin, the first polymeric component having been grafted with an unsaturated carboxylic anhydride or an unsaturated carboxylic acid, or combinations thereof, or with an epoxide; a second polymeric component having OH, SH, or NHR
2
groups where R
2
is H, C
1
-C
3
alkyl, substituted C
1
-C
3
alkyl; and a metal salt capable of catalyzing the reaction between oxygen and the second polymeric component, the polyolefin being present in an amount sufficient so that the blend is non phase-separa
Ching Ta Yen
Current Steven P.
Katsumoto Kiyoshi
Theard Leslie P.
Chevron Phillips Chemical Company LP
Reddick Judy M.
Williams Morgan & Amerson P.C.
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