Coated polyester preforms and articles

Abstract

This invention relates to articles made of polyester, preferably polyethylene terephthalate (PET), having coated directly to at least one of the surfaces thereof one or more layers of thermoplastic material with good gas-barrier characteristics, and novel methods of making such articles. Preferably the barrier-coated articles take the form of preforms coated by at least one layer of barrier material and the containers blow-molded therefrom. Such barrier-coated containers are preferably of the type to hold beverages such as soft drinks, beer or juice. The preferred barrier materials have a lower permeability to oxygen and carbon dioxide than PET as well as key physical properties similar to PET. The materials and methods provide that the barrier layers have good adherence to PET, even during and after the blow molding process to form containers from preforms. Preferred barrier coating materials include poly(hydroxyamino ethers). In one preferred method, preforms are injection molded then barrier-coated immediately thereafter.

1 . A process for the production of coated plastic articles comprising: 
 providing a polyester article having an exterior surface and an interior surface;    contacting at least a portion of the exterior surface of the polyester article with a solution or dispersion of a Phenoxy-type Thermoplastic material, thereby forming a coating layer on at least a portion of the exterior surface of the article; and    drying the article until no solution or dispersion remains on the coated exterior surface of the article.    
   
   
       2 . The process of  claim 1 , wherein the step of contacting comprises one or more of dip or spray coating the article with the solution or dispersion.  
   
   
       3 . A method for making a coated polymeric article comprising: 
 injecting molten a first polymeric material through a first gate into the space defined by a first mold half and a core mold half to form a polymeric article comprising an inner surface and an outer surface, wherein the first mold half and the core mold half are cooled by circulating fluid, and the first mold half contacts the outer polymer surface and the core mold half contacts the inner polymer surface;    allowing the molten polymer surface to remain in contact with the mold halves until a skin forms on the inner and outer polymer surfaces, the skin surrounding a core of molten polymer in the polymeric article;    removing the first mold half from the polymeric article;    allowing the skin on the outer polymer surface to be softened by heat transfer from the core of molten polymer while the inner polymer surface is cooled by continued contact with the core mold half;    placing the polymeric article into a second mold half, wherein the second mold half is cooled by circulating fluid;    injecting a molten second thermoplastic material through a second gate into the space defined by the second mold half and the outer polymeric surface to form a coated polymeric article;    allowing the molten second material to remain in contact with at least the second mold half;    removing the second mold half from the coated polymeric article; and removing the coated polymeric article from the core mold half.    
   
   
       4 . The method of  claim 3 , wherein the article is a preform.