US 3793067 A
Coating composition for applying grease resistant, non-sticking coatings to sheets of cellulosic material and the resultant products which are suitable for use in storing, displaying and cooking food products, the coating composition comprising at least one thickener or film forming material, a Werner type chromium complex and water.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Gallino Feb. 19, 1974 1 FOOD RELEASE COATING  Inventor: Robert Gallino, Englewood Cliffs,
 Assignee: Lowe Paper Company, Ridgefield, NJ. I
 Filed: June 16, 1972  App]. N0.: 263,506
Related US. Application Data  Continuation-impart of Ser. No. 13,193, Feb. 20,
 US. Cl 117/155 UA, 117/121, 117/161 UE  Int. Cl D211! 1/38  Field of Search 117/155 UA, 161 UE, 121
 References Cited UNITED STATES PATENTS 2,273,040 2/1942 ller. 117/100 X 2,356,161 8/1944 Iler 117/121 X 2,356,879 8/1944 Pense et al.... 117/142 2,999,768 9/1961 Boresch 117/121 3,484,271 12/1969 Kaliski et a1. 117/62.1 3,558,676 l/l97l Doherty 117/162 X Primary Examiner-William D. Martin Assistant ExaminerM. R. Lusignan Attorney, Agent, or Firm-Albert C. Nolte, .lr.; Edward B. Hunter; C. Bruce Hamburg 1 Claim, No Drawings 7 1 FOOD RELEASE COATING This is a continuation-in-part of Ser. No. l3,l93, filed Feb. 20, 1970, now abandoned.
In the use of brown and serve" packages by the food industry it is the conventional practice to remove the food from the original package, transfer the same to and to bake the same on a previously prepared usual metal cookie tray or pan. This is also the case in connection with the conventional roll, cookie or biscuit baking carried out in the home or even on a commercial scale. That is, the cookies, etc. are baked on a large previously greased metal cookie tray.
It is an object of the invention to eliminate the necessity of using metal cookie or baking trays for the actual baking of the food and therewith the associated disadvantages of storage, cleaning, rust prevention, etc.
In accordance with the invention, the bread, biscuits, cookies, buns, rolls, etc., can be cooked directly in the paper board package in which they have been stored and displayed under conventional conditions e.g., 25 minutes at 350375F. The storage, display and baking means are prepared in accordance with the invention by applying onto a sheet of cellulosic material, for example, a paperboard substrate, a coating composition consisting of a thickener or film forming material, a Werner type chromium complex and water, using conventional coating techniques. The resultant product is then suitable for use both as the packaging means and as the cooking pan for the food. The same coating can be applied onto paperboard where the resultant prodnets are intended for use asdisposable cooking trays.
The coating of the invention serves to impart two distinct unique qualities to the underlying cellulosic material and namely 1. grease resistance; and
2. the ability to allow the food to be very easily released from the paperboard without any necessity of greasing the pan prior to the baking orcooking opera tron.
The coating is readily applied by all of the known conventional methods. It is normally applied out of a water based system and, therefore, no expensive and often dangerous solvent recovery systems are required.
The coating composition in accordance with the invention comprises a thickener or film forming material such as polyvinyl alcohol, a Werner type chromium complex which is preferably a chrome-stearato complex, for example, Quilon (DuPont), and water.
The components can be readily mixed in proper proportions for obtaining the results above mentioned.
In order to achieve the desired food release function of the coating, the chrome complex must constitute at least about 2 percent by weight of the coating formulation. A coating viscosity of no less than about cps., measured in Brookfield units at 72F. at 10 rpm, must be maintained to give proper coating spread. For this purpose a conventional thickener or film former, such as polyvinyl alcohol, carboxymethyl-cellulose, sodium alginate, starches and the like, may be included in the formulation. Such a thickener or film former as polyvinyl alcohol serves the additional function of imparting additional grease resistance to the coating.
It is of great importance that the cellulosic substrate not be so porous as to be over-absorbent. Such an overabsorbent substrate will allow excessive drainage of the food release coating, whereupon insufficient coating will remain on the surface to provide proper release. Accordingly, a minimum Cobb Size Specification of about 0.30 g. water absorbed must be maintained. This may be done by any of the known methods in the art, such as application of size either added in the furnish or onto the surface, application of a base coat, glazing, supercalendering, or similar finishing operations. On
7 the other hand, surfaces non-wettable by water, such as attained by treating with materials such as wax, untreated polyolefins or water repellent chemicals, which cannot be coated with formulations of the invention by normal coating methods, are to be avoided.
Conventional coating or sizing application can be carried out before the application of coating of the invention by conventional procedures, such as application of two coats in one pass, or pre-sizing and coating in one pass, or beater sizing and coating on a paper machine, or the like.
- An example of a grease resistant ready release coating in accordance with the invention is the following:
Polyvinyl alcohol 6 wt.% aqueous solution I00 gallons stearato chrome complex 33 wt.% isopropyl alcohol solution 9 gallons water 25 gallons.
Application air knife coate'r Paperboard 0.024 inch coated bleached sulphate Weight Coat Application 3.0 gals/3000 sq. ft.
While the invention has been described by reference to preferred embodiments, it is intended that all embodiments within the spirit of the invention be included within the scope of the claims.
What is claimed is:
l. Coated paperboard having grease resistant and non-sticking properties comprising a sheet of paperboard having a minimum Cobb Size Specification of about 0.30 g. water absorbed coated with a mixture consisting essentially of polyvinyl alcohol thickener and a sufficient proportion of Werner type chromium complex to impart said properties to the coated paperboard.