US 2091633 A
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Patented Aug. 31, 1937 UNITED STATES SANITARY FOOD CONTAINER AND METHOD MAKING Mark W. Frishkorn, Cincinnati, Ohio, assignor to The International Printing Ink Corporation, New York, N. Y., a corporation of Ohio N0 Drawing.
This invention relates to food containers and aims to provide metal containers which will keep foodstuffs of all sorts free from contamination of taste and the interior surface of the container free from contamination of color.
The object of this invention is to provide a Standard lining for alkaline foodstuff containers, including particularly those used for asparagus and spinach.
It has heretofore been customary to provide metal food containers such as tin cans with a lining consisting of an oleoresinous film with a moderate proportion of zinc oxide varying from 3 to 5%. It has been found that such linings permit two-way reactions between the food and the metal, which result in contaminating the taste of the food. This is particularly true of such foodstuifs as asparagus and spinach and other strongly alkaline and delicately flavored foodstuffs, increasing the two-way reaction and being more deleteriously affected by the resultant transfer of odor and taste, causing a decided contamination of taste. In fact, no suitable lining for these two foodstuffs has hitherto been developed or employed, even though zinc oxide has been incorporated in the lining composition.
I have discovered that two-way reactions through an oleoresinous film may be inhibited and largely prevented by incorporating in the film overlapping plate-like particles of a chemically inert substance. The inhibiting of twoway reaction through the film appears to be the result of the screening action of the overlapping plate-like particles. My invention, based on this discovery, provides an inexpensive metal food container in which black-etch is eliminated and contamination of taste is reduced to a minimum.
A food container embodying my invention comprises a metal receptacle such as a tin can having on its inner surface a film incorporating a substantial amount of overlapping plate-like particles of a chemically inert substance. Most satisfactory results have been obtained by incorporating in the dried film approximately 20% by Weight of plate-like particles of mica (magnesium aluminum silicate).
In making such a food container, I incorporate the mica in an oleoresinous varnish containing a minor proportion of zinc oxide such as has heretofore been used for coating metal food containers, and then apply the varnish to the inner surface of a metal receptacle or to one surface of a piece of sheet metal from which the receptacle may be formed. While any type of oleoresinous varnish heretofore used for food containers'may be used, I prefer to incorporate the mica in a varnish which is set by baking. Such a varnish may consist of a phenol formaldehyde resin and a drying oil such as tung ,oil. While the propor- Application August 7, 1935, Serial No. 35,065
tion of mica in the varnish is most desirably about 10% by weight, it may be varied from not less than 5% to not more than 15%.
The following is a specific example of my composition in which zinc oxide is incorporated for alkaline foodstuffs, including asparagus and. spinach: Example No. 1
Modified phenol-formaldehyde resin (Paranol) 16.55 Tung oil 24.96 Linseed oil 2.10 Kerosene (Rayolite) 8.35 Coal tar naptha (Hi Flash naptha) 9.85 Petroleum naptha (Varnolene) 26.35 Mica 9.34 Zinc oxide 2.50
The following example illustrates my composition for fruits and acid foodstufi when zinc oxide is not employed:
Example No. 2
Modified phenol-formaldehyde resin (Paranol) 19.25 Tung oil 30.50 Kerosene (Rayolite) 10.00 Petroleum naptha (Varnolene) 22.38 Coal tar naptha (I-Ii Flash naptha) 11.40 Mica 6.47
What I claim is:
1. A food container consisting of a metal receptacle and a film on the inner surface of said receptacle incorporating overlapping plate-like particles of mica which inhibit two-way reactions through the film.
2. A container for alkaline foodstuffs consisting of a metal receptacle and an oleoresinous film containing a minor proportion of zinc oxide on the inner surface of said receptacle incorporating overlapping plate-like particles of mica which