US 2047975 A
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restricting the growth of fungi;
Patented July 21, 1936 UNITED STATES PAPER AND PROCESS FOR THE MANUFACTURE OF SAME Leo Libcrthson, New York, N. Y., assignor to L.
Sonneborn Sons, Inc., a corporation of Delaware No Drawing. Application October 29, 1932, Serial No. 640,344
2 Claims. (Cl. 91- -68) The invention is applicable to the impregnation 'of paper with a copper compoundfor the purpose of inhibiting or preventing the growth of fungLetc; and for thepurpose of inhibiting 5 or preventing the propagation, passage or transfer of fungi, etc; through the impregnated paper.
The impregnation with a copper compound in aqueous solution has already been practiced, and copper so introduced is known to be efficacious in In general, I have found that better results than those obtainable by' use of aqueous solutions are obtainable by the process hereinafter described, both as to the amount of copper with which the material may be impregnated and with respect to the efiicacy and permanence of retention. In accordance with thisprocess, the copper in the form of an oil soluble copper compound is dissolved in a hydrocarbon and the material is then impregnated with the solution of the copper compound insaid hydrocarbon. The hydrocarbons generally may be employed for this purpose, and for certain purposes a hydrocarbon which is normally erically referredto as the normally solid hydrocarbons, I may, within the general purview of the invention, employ any oil soluble copper compound, such'as copper naphthenate or copper sulphonate, including both the aromatic and aliphatic sulphonates of copper. The preferred material for my'process is, generally speaking, a 4 copper soap, viz, a. compound of copper with a fatty acid.
A paper impregnated in accordance with my process may be utilized, for example, as a wrapping material in any case where the fungicidal properties of copper are of value. An example of such use is for the purpose of wrapping fruit for storage and/or transportation, in order to mini-- mize the spread of rot (as for example Botrytis rot) or similar diseases frominfected to healthy fruit; the paper so prepared is of course susceptible to other uses. Some paper utilized for this purpose has been heretofore impregnated with copper sulphate. Such paper may, however, become dry and brittle, cracks may occur in the 55 material, or the copper content may be lost as tailings, etc, may be employed; and such mate-. rials, including wax, petrolatum, etc., will be genquires that the impregnating material shall be correspondingly high in its content of copper carried in solution. The material used for impregnation must, notwithstanding, possess a desirable ,15
consistency to permit of easy application and thorough penetration at the temperature of impregnation, I have found that both desiderata may be obtained through the use of a mixture of copper oleate and copper resinate dissolved as 20 aforesaid. This mixture has sufficient solubility in hydrocarbon materials so that a relatively large percentage of combined copper may be introduced to the paper. I preferably employ for this purpose a, mixture of copper oleate and cop- 25 per resinate in which the copper oleate is roughly from 25 to 75% of the total copper soap, and the copper soaps are present in the hydrocarbon to the extent of from 25 to 75% of the whole.
A still further improvement results from the preliminary formation of the copper soap by. the metatheical reaction in the presence of water between a water soluble soap and a water soluble copper compound. The copper soap may, for example, be made by reacting a sodium soap with copper sulphate. If this reaction is carried out in the presence of the hydrocarbon, the copper soap will be found at the expiration of the reaction dissolved in the hydrocarbon. Where a waxlike or normally solid hydrocarbon is employed, the reaction will of course be carried out at a temperature above the melting point of the same. In any event, after the completion of the reaction the mixture is permitted to remain quiescent for aperiod, whereupon straitification ensues, resultingin the formation of a lower aqueous layer containing the water soluble salt formed by the reaction, and simultaneously resulting in the formation of an upper hydrocarbon layer containing the copper soap dissolved therein. The aqueous layer may be withdrawn and discarded, and the hydrocarbon layer, preferably after blowing or otherwise drying to free it, from residual moisture, is ready for use as an impregnating medium. Material prepared in thisway is homogeneous, does not require centrifugin and I I claim:
easily be prepared with a copper content 'of at least 8%. The desirable'features which have been specifically illustrated in application to the impregnation of paper, or tothe manufacture of. the hydrocarbon material containing the dis,- solved copper soap, are of course applicable: gent to any application of the impregnating; material to materials in the web.
I'he material is preferably applied to the web in fluid condition following the .usual methods for impregnating with similar materials, such as paraflin and petrolatum. It is a further advantage of this process that it not only renders' the material treated proof against fungi, but alsomakes it moisture proof.
fore my intention that 'theinvention only by the appended claims or their equivalents,
wherein I have endeavored to claim broadly all;
inherent novelty. I
1. A wrapping paper impregnated with petrolatum containing dissolved therein an oil soluble copper compound, andadapted-to substantially permanently prevent the spreading of fungi from a point of fungus-propagation, said paper being substantially permanently water-repellent and containing at least 1% of copper.*
2. A wrapping paper impregnated. with petrol'atum containing dissolved therein copper oleateio and copper resinate, and. adapted to substantially permanently prevent the spreading of fungi from a point of fungus propagation, said paper being substantially permanently water-repellent, said copper oleate being present in the proportions of 15- from 25 to 75% of the total amount of copper oleate and copper resinate present, and the amount of hydrocarbon present ranging from. one-third to three times the amount by weight of, copper oleate and copper resinate.