Illinois Tool Works Inc.

Signode Corporation

Karl G Adams

Russell J Gould

Manuel C Enriquez

James P Nelson

Gary L Vadnais

Donald L Van Erden

Donald Van Erden

A process for preparing a PET flake mixture for use in connection with the fabrication of high-performance plastic strapping comprises the steps of initially collecting post-consumer and non-post-consumer PET materials having an initially wide range of relatively low intrinsic viscosity (IV) values with a relatively low average intrinsic viscosity (IV) value, and processing the same through solid state polymerization (SSP) so as to obtain a wide range of relatively high intrinsic viscosity (IV) values with a relatively high average intrinsic viscosity (IV) value. The initially collected materials are chopped into flakes and chunks, and the chunks are flattened so as to render the remaining mixture comprised substantially entirely of flake materials or segments. This is advantageous because the flake segments, as opposed to the chunk segments, are able to be substantially increased in intrinsic viscosity (IV) values and within a relatively short period of time. The initially collected materials have intrinsic viscosity (IV) values which are within the range of 0.60-0.80 dl/g, and as high as 0.90 dl/g, and the diversity of such materials is underscored or emphasized by the fact that the difference in such intrinsic viscosity (IV) values of the initial or starting materials is at least, or greater than, 0.05 dl/g, is probably at least 0.10 dl/g, and can be within the range of 0.10-0.30 dl/g.

Inline solid state polymerization of pet flakes for manufacturing plastic strap

The present invention describes a process of making strap using both post consumer and non-post consumer PET of wide distribution intrinsic viscosity (IV) through direct solid state polymerization in a flaked state to produce PET with increased, heterogenous IV suitable for high performance strap extrusion. The process increases the IV of post-consumer resins, consisting principally of polyethylene terephthalate (PET), by chopping the post-consumer plastic into flakes and chunks, rolling the flakes and chunks, preheating the flakes, and further heating the flakes and chunks in an atmosphere of hot nitrogen gas, thereby increasing the intrinsic viscosity. PET polymers having increased viscosities according to the present invention provide a polymer useful in manufacturing high performance strap.

Inline solid state polymerization of pet flakes for manufacturing

A joint having improved snag resistance and peel strength is formed between overlapping end portions of a thermoplastic strap by the method and apparatus of the present invention. The thermoplastic strap is formed into a loop having overlapping inner and outer end portions which are joined to one another by a resolidified thin layer of formerly melted material from each of the overlapping strap end portions. Resolidified material extends completely to an inwardly tapered end of the outer strap end portion to provide the improved joint. A resolidified mass of formerly molten material also is present in front of the tapered end to further protect it against snagging.

Strapping joint and method and apparatus for forming same

A joint having improved snag resistance and peel strength is formed between overlapping end portions of a thermoplastic strap. The thermoplastic strap is formed into a loop having overlapping inner and outer end portions which are joined to one another by a resolidified thin layer of formerly melted material from each of the overlapping strap end portions. Resolidified material extends completely to an inwardly tapered end of the outer strap end portion to provide the improved joint. A resolidified mass of formerly molten material also is present in front of the tapered end to further protect it against snagging.

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Schaumburg, IL, United States of America

Karl G Adams