Scouring pads for the cleaning of pots and pans have been in use for a number of years. Scouring pads are used to bring a scouring surface of desired roughness and/or abrasiveness into contact with the soiled surface of a pot or pan. The body of the scouring pad is easily deformable to permit the surface of the pad to conform to the surface of the pot or pan being cleaned and is also of porous construction to provide a water-holding capacity so that water or soap solution is continuously supplied to the cleaning surface.
The surface of a scouring pad is desirably of sufficient roughness or unevenness and of sufficient toughness to facilitate the removal of large, loosely held food deposits from the surface of the pot or pan. The surface should also have sufficient abrasiveness to facilitate the removal of hard, low volume deposits which adhere strongly to the inner surfaces of pots or pans having metallic or vitreous surfaces. Pots or pans having non-sticking surfaces of Teflon or of some other non-wettable resin cannot be scoured with an abrasive surface without damage to the surfaces and have no need for scouring with an abrasive surface because the food deposits thereon are not strongly adherent.
In general, the scouring pads available have been designed either with an abrasive surface for the treatment of pots and pans having metallic or vitreous surfaces, or with a roughened non-abrasive surface for the treatment of pots and pans having resinous non-sticking surfaces.
One early form of pot cleaning pad which is still in use is a pad made of steel wool fibers. Steel wool fibers provide abrasiveness suitable for metallic and vitreous pots and pans and have suitable water-holding capacity and conformability. Steel wool pads do not have surfaces of sufficient roughness for the effective cleaning of bulky food deposits. In addition, they cannot be used on Teflon-coated pots and pans and are also subject to rusting which shortens their effective life.
To provide desirable roughness to steel wool, scouring pad structures are utilized which are made in accordance with Winston U.S. Pat. No. 3,182,346 and which have a corrugated metallic wool layer adhered to a flexible foam layer. Such pads cannot be used safely on resinous non-sticking surfaces, such as Teflon-coated pots and pans because the metallic wool surface is too abrasive and the flexible foam surface is too soft and smooth.
Scouring pads have also been made in accordance with Politzer U.S. Pat. No. 3,080,688 and having a lofty, open, non-woven fibrous web bonded to a cellulose sponge layer. The non-woven fibrous layer preferably has abrasive particles adhered to its fibers in the manner described in Hoover U.S. Pat. No. 2,958,593.
Such pads are disclosed as being made by bringing together a non-woven fibrous web and a layer of sponge-forming mass so that some of the fibers of the web become embedded in the sponge as it solidifies. Such penetration of fibers into the sponge, however, is relatively shallow penetration which, while it provides good adhesion between the two layers, does not provide protection against the delamination of the sponge layer at a depth beyond the penetration of the web fibers. In addition, the method described requires that the pads be fabricated only by those who have facilities for the in situ production of foam.
Other scouring pads have been made by adhering a lofty, open, non-woven fibrous web containing abrasive particles to a cellulose sponge layer, or a flexible polyurethane sponge layer by a layer of adhesive. Such pads cannot be used on Teflon-coated pots and pans and are also subject to possible separation in use by reason of an improperly cured adhesive layer, or by reason of delamination of the sponge, itself.
Some scouring pads have been designed specifically for use on Teflon-coated pots and pans, utilizing scouring surfaces which contain no abrasive particles. One type of pad for this purpose is an open non-woven web of coarse nylon monofilament which has the desired rough surface and the desired toughness, but very little water-holding capacity. Other pads for Teflon-coated pots and pans utilize a coarse, open woven or non-woven web of nylon or other tough fiber either wrapped around, or adhered to a cellulose or flexible polyurethane foam. Such pads have adequate water-holding capacity but, because of the lack of abrasive particles, are of limited effectiveness in the removal of hard, adherent, soil from metallic or vitreous pots and pans.
One scouring pad designed to be used on different types of surfaces is the pad disclosed in Klein U.S. Pat. No. 3,175,331. The Klein pad comprises two non-woven fibrous batts having resin-coated fibers, the batts being heat-sealed to each other at their edges and a bar of soap in the sealed space between the batts. One batt may, if desired, have abrasive particles while the other batt is free of such particles to make the pad suitable for use on surfaces of different types. This pad is limited in conformability and in water-holding capacity and is subject to the possibility of coming apart at the edges in rough use.