Method for treating polyesters and, in particular, cleaning and decontaminating polyesters
AssigneeThe Coca-Cola Company
InventorJohn A. Schwartz, Jr.
Life of this patent
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Abstract
A method for treating polyesters comprises combining discrete particles of a polyester with an alkaline composition such that the alkaline composition coats the polyester particles. The particles are then heated in an environment that is at least substantially free of water. The method can be effectively used in cleaning, decontaminating and even increasing the intrinsic viscosity of polyester materials. Moreover, when used in the recovery of polyester materials containing contaminants and/or impurities, the method can provide a superior polyester product both in terms of intrinsic viscosity and color.
Claims49
A method for treating polyester comprising:
- (a) combining polyester with an effective amount of an alkaline composition to coat at least a portion of the polyester, the amount of alkaline composition being sufficient to react with only a portion of the polyester;
- and
- (b) heating the mixture to a temperature not greater than the melting point of the polyester wherein step (b) is performed in an environment which is at least substantially free of water.
A method for recovering polyesters containing contaminants and/or impurities comprising:
- (a) mixing polyester-containing materials with an alkaline composition, which alkaline composition is employed in an amount effective to react with only a portion of the polyester in the polyester-containing material;
- (b) heating the mixture to a temperature effective to saponify a portion of the polyester but insufficient to melt the polyester;
- and
- (c) separating at least a portion of the polyester from the remaining materials, wherein step (b) is performed in an environment which is at least substantially free of water.
A method for treating polyester comprising:
- (a) coating a polyester with an effective amount of an alkaline composition to cover at least a portion of the polyester, the amount of alkaline composition being sufficient to react with only a portion of the polyester;
- and
- (b) heating the mixture to a temperature not greater than the melting point of the polyester for a period of time sufficient to increase the intrinsic viscosity of the polyester, wherein step (b) is performed in an environment which is at least substantially free of water.
A method for solid-stating polyester particles comprising:
- (a) providing discrete particles comprising at least one polyester;
- (b) coating the polyester particles with an alkaline composition in an amount sufficient to react with only a portion of the polyester;
- and
- (c) heating the coated particles to an effective solid-stating temperature and for an effective solid-stating period of time, said heating step being performed in an environment that is at least substantially free of water.
A method for treating polyester, comprising:
- providing a polyester-containing material;
- mixing the polyester-containing material with an alkaline composition;
- introducing the mixture into a reaction chamber;
- heating the mixture to a temperature sufficient to saponify a portion of the polyester;
- and
- introducing a dry gaseous stream into the reaction chamber during said heating step so that the reaction chamber is at least substantially free of water during said heating step.
Dependencies are inferred from the claim text.