Reinforced film and method of manufacturing same
AssigneeBay Mills Limited
InventorsJohn F. Porter, D. Mark Woiceshyn
Life of this patent
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Abstract
A reinforced, impervious, unitary film and a method for making the same are disclosed. In a preferred embodiment, a film is produced from a layer of weft inserted warp knit scrim and at least one layer of lightweight, porous mat, together being impregnated with a suitable thermoformable plastic in liquid form such as PVC plastisol, then being set and calendered under pressure to deform the plastic and create a continuous, non-porous, unitary film. The resulting product is highly resistant to water absorption and hydrostatic pressure and essentially non-wicking.
Claims43
A continuous process for manufacturing a non-porous, reinforced, impervious, unitary film, said process comprising the steps of:
- providing a low viscosity impregnating liquid comprising a thermoformable plastic having a sufficiently high percentage of solids to liquids so that a non-porous unitary film is capable of being formed upon calendering;
- providing an open fabric having a plurality of yarns in a first direction and a plurality of yarns in a second direction;
- providing at least one lightweight, porous, organic, cellulosic mat comprising a plurality of filaments;
- continuously feeding the fabric and the mat from respective feed ends to an exit end;
- impregnating the fabric and the mat with the impregnating liquid, the impregnating liquid flowing into the open fabric and the porous mat to impregnate the yarns of the fabric and to surround the filaments of the mat and to form a side by side impregnated combination of fabric and mat in which the weight of the thermoformable plastic carried on the impregnated combination is 100 to 800% measured as dry pick-up weight relative to the combined weight of the fabric and the mat, which amount is sufficient to be deformed into a non-porous unitary film upon calendering, the mat bridging gaps between the yarns of the fabric;
- continuously setting the plastic of the impregnated combination of fabric and mat to eliminate essentially all carrier liquid and to form an impregnated combination of fabric, mat, and set plastic, the set, impregnated combination having gaps between the yarns of the fabric bridged by mat impregnated with set plastic and having a predetermined porosity;
- and
- continuously deforming the set, impregnated combination of plastic, fabric, and mat by calendering with a heated calender roll of sufficient heat and at a sufficient pressure gradient to deform the plastic to further impregnate and surround the yarns of the fabric and filaments of the mat with the plastic and to close essentially all remaining pores and voids in the impregnated combination, to create a non-porous, impervious, continuous, low-wicking, essentially void-free, unitary film having a reinforcement of fabric and mat embedded therein.
An impervious, reinforced, unitary film comprising:
- an open fabric comprising yarns;
- at least one lightweight porous mat comprising cellulosic fibers;
- and
- a thermoformable plastic impregnating the fabric and the mat;
- the thermoformable plastic impregnating the fabric and mat having been set in situ to eliminate essentially all carrier liquid and, after setting, the plastic, fabric and mat having been calendered under heating conditions such that yarns of the fabric and filaments of the mat are impregnated with the plastic and adhere to the plastic, and the combination of plastic, fabric and mat forms an impervious, reinforced, unitary film.
Dependencies are inferred from the claim text.