Reducing concentration of organic materials with substituted cyclodextrin compound in polyester packaging materials
Volatile organic compound or other materials are produced in the thermoplastic manufacture of thermoplastic polyester beverage containers. Such materials can be eluted into beverages such as carbonated beverages, sparkling or still water from the polyester. Such thermoplastic polyester resins can be manufactured with a material that can prevent the formation of, or react with, and absorb volatile by-products during the formation of thermoplastic preforms or containers from the thermoplastic pellet or chip. Further, as the preform is blown into a polyester container, the active materials of the invention prevent the generation of additional undesirable volatile materials. Lastly, the scavenger material can act as a barrier that prevents transport of materials from the exterior of the container into the container contents.
1. A method of making a polyester chip comprising the steps of:
(a) forming a liquid comprising an effective amount of a substituted cyclodextrin compound to trap or prevent transport of a material through a polymer layer;
(b) introducing the liquid comprising the substituted cyclodextrin into a stream of molten polyester proximate to a mixing means in a process device to form a treated stream;
(c) passing the treated stream through an extruder exit orifice forming the polyester chip; and
(d) subjecting the polyester chip to solid state polymerization.
2. The method of claim 1 wherein the liquid comprising about 1.0 to 50 weight percent of the substituted cyclodextrin compound.
3. The method of claim 1 wherein the polyester comprises molten polyethylene terephthalate and the mixing means is proximate to an extruder exit orifice.
4. The method of claim 1 wherein mixing means is next adjacent to the extruder exit orifice.
5. The method of claim 1 wherein the liquid comprises an oil and the substituted cyclodextrin compound.
6. The method of claim 1 wherein the polyester comprises at least 60% by weight polyethylene terephthalate units and up to 40% by weight other polymers.
7. The method of claim 1 wherein the polyester comprises at least 60% by weight polyethylene naphthalate units and up to 40% by weight other polymers.
8. The method of claim 1 wherein the cyclodextrin compound has a substituent substantially on at least one —OH group on the -6 position of the glucose moiety in the cyclodextrin.
9. The method of claim 1 wherein the cyclodextrin compound comprises a cyclodextrin 6-O-Methyl ether.
10. The method of claim 1 wherein the cyclodextrin compound comprises a cyclodextrin 6-O Acetyl ester.
11. The method of claim 1 wherein the cyclodextrin compound comprises a degree of substitution of about 0.5 to 1.8 in an amount of about 100 parts by weight to about 1400 parts by weight of the cyclodextrin compound per each one million parts of polyester resin.
12. The method of claim 1 wherein after solid state polymerization, the chip comprises crystallized polyester.