Cured In Place Pipe Liner With Styrene Barrier

[0007]A cured in place liner for a passageway or pipe comprising a barrier layer to greatly reduce the migration of styrene through the liner. The liner has at least one layer of resin absorbent material, preferably a non-woven resin absorbent material. The liner also has a thermoset resin, preferably a styrene polyester resin, impregnated into the resin absorbent material layer. The liner has a thermoplastic coating attached to the resin absorbent material layer. The coating comprises a thermoplastic barrier layer, which is preferably either a high hardness thermoplastic polyurethane polymer or an ethylene vinyl alcohol polymer. The coating is preferably a three layer coating comprising (a) a first thermoplastic layer in contact with the resin absorbent material layer; (b) a second thermoplastic barrier layer in contact with the first thermoplastic layer and third thermoplastic layer; and (c) a third thermoplastic layer in contact with the barrier layer. The first and third layers of the coating can be made from a thermoplastic polymer selected from the group consisting of thermoplastic polyurethane (TPU), co-polyamide (COPA) and co-polyester (COPE).

One problem that occurs when using a styrene based polyester as the thermosetting resin is the migration of styrene from the resin and through the thermoplastic polymer layer coated on the resin absorbent material layer.

The styrene enters the cavity of the cured in place pipe and contaminates the media, such as water or steam, used to pressurize the pipe liner.

When the media is evacuated from the pipe, it must be specially processed because it is contaminated with styrene, rather than simply being diverted to the local city sewer system.

Also, the styrene odor which must also be dealt with can be a problem.