Opaque polyester containers
View Patent ↗The present invention describes both a stretch-blow-molded opaque polyester container and a method of making it. The container, typically a beverage bottle has less than 15% transmission of visible light (500 nm) through a 0.4 millimeter wall thickness. It contains from about 0.1 to about 5 wt. % of said opacifying material. The opacifying material may be any material compatible with polyester resin. The method of making the container includes introducing the opacifying material during polymerization, or prepared as a master batch for mixing with the polymer. Selection of certain opacifying materials can also result in favorable reheat properties, gas permeation-barrier improvements, and when the resin contains both opacifying material and oxygen scavenger there can be a synergistic effect with respect to CO 2 permeation.
1. A stretch-blow-molded opaque polyester container comprising: a polyester resin containing an aluminum powder opacifying material and an oxygen scavenger, wherein said oxygen scavenger comprises an oxidizable polymer and a transition metal catalyst, and wherein the oxidizable polymer is present in an amount of from 4-6 wt % of said polyester resin,
wherein said container has less than 15% transmission of visible light (500 nm) through a 0.4 millimeter thickness.
2. The container of claim 1 , wherein said polyester resin contains from about 0.1 to about 5 wt % of said opacifying material.
3. The container of claim 1 , wherein said oxygen scavenger is partially aromatic polyamide, whereby said container has a carbon dioxide permeation of less than about half that of a container with just said powdered aluminum or of a container with just said partially aromatic polyamide.
4. The container of claim 1 , wherein said polyester resin contains from 0.16 to about 4 wt % of said aluminum powder opacifying material.
5. The container of claim 1 , wherein said aluminum powder opacifying material has a particle size of between 10.2 and 83 microns.
6. The container of claim 1 , wherein said container exhibits a CO 2 permeation that is improved by at least about 15% compared with a container having just polyester resin.