Pressurizable thermoplastic container having an exterior polyurethane layer and its method of making
AssigneePPG Industries, Inc.
InventorsKen W. Niederst, John R. Zern, Jerome A. Seiner
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Abstract
Pressurizable thermoplastic containers, such as those made from polyethylene terephthalate containing a polyurethane layer on the exterior surface thereof are disclosed. The polyurethane layer which is typically applied by a coating process provides the bottle with resistance to stress cracking. The containers are useful as refillable bottles for carbonated beverages which have a tendency to stress crack.
Claims9
In a thermoplastic container for carbonated beverages which is prepared by a blow molding technique and has a rigid structure such that the container can be pressurized;
- the container having a thick wall construction such that the container can be reused;
- the thermoplastic container having a tendency to stress crack after reuse and subsequent hot caustic washings and refillings with carbonated beverages;
- said thermoplastic container being further characterized as having a polyurethane layer derived from an organic polyisocyanate and a polymeric polyol which is cured thermally on the exterior surface thereof;
- said polyurethane layer having a dry film thickness of 0.2 to 1.5 mils to provide resistance to the formation of microcracks.
In a thermoplastic container for carbonated beverages which is prepared by a blow molding technique and has a rigid structure such that the container can be pressurized;
- the container having a complexly configured base such that it has a number of protruding feet molded into the base area or has a rim portion surrounded by an inwardly sloping base portion, so as to make the container free standing and having a thick wall construction such that the container can be reused;
- the thermoplastic container having a tendency to stress crack after reuse and subsequent hot caustic washings and refillings with carbonated beverages;
- said thermoplastic container being further characterized as having a polyurethane layer derived from an organic polyisocyanate and a polymeric polyol which is cured thermally on the exterior surface thereof;
- said polyurethane layer having a dry film thickness of 0.2 to 1.5 mils to provide resistance to the formation of microcracks.
Dependencies are inferred from the claim text.