Method for increasing barrier properties of thermoplastic substrates
AssigneeAir Products and Chemicals, Inc.
InventorsBernard D. Bauman, Rajendra K. Mehta, Mark A. Williams
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Abstract
The present invention is a method for improving the barrier properties of thermoplastic substrates. A surface of the thermoplastic substrate is contacted with a reactive gas stream having an F.sub.2 concentration greater than or equivalent to 0.0001 atm. partial pressure of F.sub.2 per atm. total pressure and sufficient oxygen such that the F.sub.2 /O.sub.2 ratio is less than or equal to about 100, with the remainder being additional reactive and/or non-reactive components. A barrier coating material is applied to the treated surface of the substrate and subsequently undergoes a curing step to form the final product.
Claims17
A method of increasing the barrier properties of a thermoplastic substrate selected from the group consisting essentially of polyethylene, polypropylene, polyethylene terephthalate, polyethylene terephthalate glycol, polycarbonates, polystyrene, polyamides, polybutylene terephthalate, polymethyl pentene, polyvinyl chloride and copolymers thereof, said method comprising the steps of:
- (a) contacting at least one major surface of the thermoplastic substrate with a gaseous reactant stream having an F.sub.2 concentration greater than or equivalent to 0.0001 atmosphere partial pressure of F.sub.2 per atmosphere total pressure, oxygen in sufficient concentration such that the F.sub.2 /O.sub.2 volumetric ratio is less than 100, with the balance being additional reactive and/or non-reactive components;
- (b) applying to said major surface of the thermoplastic substrate, a barrier coating selected from the group consisting essentially of polyvinylidene chlorides, ethylene vinyl alcohols, epoxies, polyurethanes, acrylics, polyvinyl chloride, ureaformaldehyde, silicones and fluorocarbons;
- and
- (c) curing said barrier coating.
A polymeric container having improved barrier properties, said container comprising:
- (a) a thermoplastic substrate selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, polyethylene terephthalate glycol, polycarbonate and polyvinyl chloride of which at least one major surface has been contacted with a reactive gas stream having an F.sub.2 concentration greater than or equivalent to 0.0001 atmosphere partial pressure of F.sub.2 per atmosphere total pressure and O.sub.2 in sufficient concentration such that the F.sub.2 /O.sub.2 volumetric ratio is les than 100, for a period of time between one second and five minutes, and
- (b) a barrier coating selected from the group consisting of polyvinylidene chlorides, ethylene vinyl alcohols, epoxies, polyurethanes and fluorocarbons bonded, in the absence of any bonding agent, to the surface of said thermoplastic substrate which was contacted with said reactive gas stream.
Dependencies are inferred from the claim text.