Grease absorbing pad with anti-stick coating

Improved disposable three layered pads for collecting cooking grease produced during the cooking of fatty foods particularly in the cooking area of a microwave oven as described in U.S. Pat. No. 5,814,396. These pads comprise (a) a top grease absorbing layer having at least one ply of a grease absorptive sheet; (b) a middle grease and high temperature resistant layer; and (c) a bottom layer composed of an anti-stick heat insulating sheet. The pad is dimensioned to cover a substantial portion of the bottom cooking area of a microwave oven when used in these devices. The top layer is from 2 to 50 times thicker than the middle and bottom layer. The improvement comprises a small yet effective amount of anti-stick coating on the top layer of these three layered pads. These anti-stick coatings may be selected from such substances as vegetable oils, animal fats and synthetic lubricants.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 This invention relates to disposable pads for absorbing cooking grease.
 2. Description of the Prior Art
 U.S. Pat. No. 5,814,396, the disclosure of which is incorporated herein by
 reference, describes an improved grease absorptive pad as being a
 disposable three layered absorptive pad for collecting and draining
 cooking grease. It is most effective in collecting grease produced during
 microwave oven cooking. The pad also may be used to drain grease from
 recently prepared fatty foods.
 The top layer is made up of at least one ply of a grease absorptive sheet.
 The middle layer is a grease resistant sheet. Finally, the bottom layer is
 an anti-stick insulating sheet. The pad is dimensioned to cover a
 substantial portion of the bottom cooking area of a microwave oven. It may
 be of any convenient size when it is used to drain freshly cooked fatty
 foods.
 The top layer of the disposable three layered pad is most often thicker
 than the middle and bottom layers. Also the top layer beneficially
 contains a plurality of plies which are readily assembled from cellulose
 fibers such as an absorptive paper. The middle layer desirably is formed
 from a high temperature stable, grease resistant plastic sheet such as
 high density polyethylene. The expression `high temperature` means the
 temperature at which fatty foods are usually cooked. The bottom layer is a
 heat insulating sheet. Cellulose fibers of the type used to form the top
 layer may be used to form the bottom layer.
 It has been found that in certain instances some foods tend to stick to
 these absorptive pads. While the portions of the pads stuck to the food
 was easily removed it would be an improvement if this occasional sticking
 could be eliminated. It is therefore an object of the invention to provide
 a grease absorptive pad that does not stick to food within which it is in
 contact. It is also an object of the invention to provide a grease pad of
 the type described which has on its surface a coating which contains an
 effective amount of an anti-stick agent.
 SUMMARY OF THE INVENTION
 The invention relates to improved disposable three layered pads for
 collecting cooking grease produced during the cooking of fatty foods
 particularly in the cooking area of a microwave oven as described in U.S.
 Pat. No. 5,814,396. These pads comprise (a) a top grease absorbing layer
 having at least one ply of a grease absorptive sheet; (b) a middle grease
 and high temperature resistant layer preferably constructed of plastic;
 and (c) a bottom layer composed of an anti-stick heat insulating sheet.
 The pad is dimensioned to cover a substantial portion of the bottom
 cooking area of a microwave oven when used in these devices. The top layer
 is from 2 to 50 times thicker than the middle and bottom layer. The
 improvement with which this invention is concerned comprises a small yet
 effective amount of anti-stick coating on the top layer of these three
 layered pads. These anti-stick coatings may be selected from materials in
 the following groupings: vegetable oils, animal fats and synthetic
 lubricants. Since the coatings will contact foods these coatings are
 further characterized as being described in EAFUS, which is an acronym for
 "Everything" Added to Food in the United States, a food additive data base
 published by the U.S. Food and Drug Administration.
 The anti-stick coating preferably is a vegetable oil, desirably a blend of
 vegetable oils combined with a dimethylpolysiloxane polymer and/or
 lecithin. The coating also may be a synthetic polymer exemplified by
 silicone polymers, floroalkylene polymers and alkane polymers. Good
 results are obtained when the coatings are either a dimethypolysiloxane
 polymer or a polyethylene.

In the drawings like parts have like numbers.
 DETAILED DESCRIPTION OF THE INVENTION
 With specific reference to the drawings there is shown in FIG. 1 a
 disposable pad designated generally by the numeral 10. This particular
 embodiment is shown as a square substantially flat pad having a top 12 and
 a bottom 14. The sides of the square are designated by the numerals 16 for
 the left and 18 for the right.
 As illustrated in FIG. 2 the disposable pad is made up of a top layer 20
 which is shown in FIG. 2 as being composed of several plies 22 of a grease
 absorptive material. The middle layer 24 is a thin, grease resistant sheet
 which is superimposed upon bottom layer 26 which acts to insulate middle
 layer from excessive heat which might cause it to stick to the bottom of a
 microwave oven. The three layers may be assembled into a unitary
 disposable grease retaining pad by means of stitching 28. Adhesives may be
 substituted for the stitching.
 In a typical embodiment of the invention, the top 12 and bottom 14 of
 disposable pad 10 would be 9 inches in width and side 16 and 18 would be
 11 inches in length. The dimensions of the disposable pad 10 will vary
 depending on the size of the bottom of the particular microwave oven in
 which they are used. In some cases these ovens have a circular rotating
 "lazy susan" type assembly located on the floor of the ovens and in such
 cases the disposable pad 10 would be circular in shape.
 Top layer 20 may be a single ply of a grease absorbing material. It may be
 a porous paper assembly likened to a tea bag filled with a grease
 absorbent such as clays e.g. vermiculite or activated carbon. Preferably
 the top layer is made from absorptive paper products such as paper towel
 stock. Middle layer 24 is preferably a thin plastic sheet of about from
 0.5 to several mills in thickness. It should be able to withstand the
 temperatures generated from microwave oven cooking without losing its
 integrity. Hydrocarbon plastic sheeting such as high density polymers of
 ethylene, propylene and butylene are preferred materials. Plastic sheeting
 containing chlorine, nitrogen or fluorine in their molecular make-up are
 not materials of choice due to the possibility of generating toxic
 compounds. Bottom layer 26 should be about the same thickness as middle
 layer 24 and should be constructed of a heat insulating material which
 shields the middle layer 24 from the hot bottom surface of microwave
 ovens. These hot surfaces may cause middle layer 24 to stick and possibly
 tear after the cooking process is finished.
 As indicated top layer 20 is preferably thicker than individual layers 24
 and 26. The ratio of this thickness differential is at least 2 to 5 times
 greater. Preferably the differential is 10 to 50 times greater.
 The top layer is coated with an anti-stick coating designated by the
 numeral 30. When vegetable oils, such as canola oil is used as the coating
 material good results are achieved when the coating is about 0.074 grams
 per sq. inch of top surface. Depending on the material used to form the
 coating the thickness may vary from between about 0.0001 to 0.1 gram per
 sq. inch. The polymers, particularly the dimethylpolysiloxanes are
 effective in very low dosages. The coating materials may be in the form of
 liquids, oil in water emulsions or suspensions. They may be applied by
 spraying, roller coating or brushing. The most important discovery of this
 invention is that even though small amounts of the coatings are used they
 are effective in preventing the sticking of food to the pads. This is
 surprising when it is believed that one skilled in the art would expect
 the coatings to be absorbed by the pads after application and hence become
 incapable of acting as an anti-sticking coating.
 EXAMPLE
 A pad of the type described in U.S. Pat. No. 5,841,396 containing several
 plies of paper toweling was spray coated on its top surface to provide a
 coating of 0.074 grams per sq. inch. The coating was the commercial
 vegetable oil product, PAM, which is a blend of canola, sunflower oils and
 lecithin. A variety of foods that had shown a tendency to stick on the pad
 were placed on the pad and cooked in a microwave oven. No sticking was
 observed.