Method of improving the environmental stretch crack resistance of RPET without solid stating

Abstract

Blends of non-solid stated RPET and an amount of PEN and / or NDC less than about 10 percent by weight are used as at least one layer of an article, such as a container or a preform for blow molding a container, having an inner layer of a thermoplastic material. The addition of the small amount of PEN and / or NDC allows the direct use of RPET without solid stating, and provides articles having environmental stretch crack resistance, color, and organoleptic properties comparable to that of virgin PET.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention is directed to articles formed directly from post-consumer, recycled, and / or regrind polyethylene terephthalate and to methods of making such articles. In particular, the present invention is directed to articles comprising a blend of post-consumer, recycled, and / or regrind polyethylene terephthalate and an amount of polyethyene naphthalate and / or naphthalene dicarboxylate of less than about 10 percent by weight of the blend in which the recycled and / or regrind polyethylene terephthalate is not solid stated under any substantial vacuum or an inert gas. [0003] 2. Related Background Art [0004] Polyethylene terephthalate (“PET”) is widely used in containers, such as beverage bottles. As a result, a substantial amount of regrind PET and recycled or post-consumer PET (collectively “RPET”) is available, due, at least in part, to widespread recycling laws. RPET can be an economical substitute for the ...

AI Technical Summary

Benefits of technology

"The present invention is about articles made of a thermoplastic material and a layer of non-solid stated RPET (recycled PET) and PEN (poly(ethylene naphthalate)) or NDC (naphthalene-dicarboxylate). The amount of PEN and / or NDC is less than 10% by weight. The article can be a container or a preform for blow molding a container. The article may also have a gas barrier layer between the inner thermoplastic layer and the second layer. The method involves obtaining an inner thermoplastic layer, blending non-solid stated RPET and PEN / NDC, and forming at least one layer of the blend around the inner layer to create the article. The technical effect is to provide articles with improved gas barrier properties and reduced amounts of PEN and NDC."

Problems solved by technology

As a result, containers formed from RPET typically have inferior environmental stretch crack resistance (“ESCR”), organoleptics, and color.

However, the low IV prevents its use in products that require a higher and / or a more homogenous IV.

The amorphous neck portions are reportedly not desirable in the process, as the rapid crystallization of the non-crystalline material releases a large amount of heat that interferes with the process.

Without solid stating, a large amount of polyamides are reportedly required to reduce the level of acetaldehyde to an acceptable level, which adversely effects the clarity of the blend.

However, only single layer preforms and containers are disclosed, which precludes the use of RPET.

However, there is no disclosure of using PEN or NDC to improve the ESCR and other properties of RPET without solid stating.

Prior art methods of using RPET require solid stating of the material, which increases the cost of any product made from the RPET.

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