US 2067988 A
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Patented Jan. 19, 1937 UNITED STATES PATENT oFFicE' v ,2,067,988 DISTINCT-IVE PAPER METHOD or MAKING SAME Burgess W. Smith, Rochester, N. Y., assignor. to The Todd Company, Inc., Rochester, N. Y., a corporation of New York No Drawing. Application April 23,.1934, Serial No. 721,977
time to prove the authenticityof'the document and further to providemeans-by which the use of chemicals is avoided, and if so desired, means to cancel the doc'umentto-prevent there-use of the paper.
- i To these and other ends,'the1invention'resides in certain combinations and improvements herechettes, silk fibres, water-marks, andother similar papers-methods admitting simulation or actual duplication of which are well known in the arts. Another class c-f distinctive papers contain certain chemicals therein which react to produce a color or other chemical reaction on the application of certain reagents. The determination of the authenticity of such papers requires the possession of these chemicals which, at times, is inconvenient and impractical.
By the means of my invention, it ispossible to produce a distinctive paper containing a word or symbol that may be developed at any time by the mere application of water which, ordinarily, is always available for the purpose and its duplication requires expensive and ponderous machinery.
I accomplished this invention by the partial or complete destruction of the sizing effect of ordinary paper so as to. form on the ground of the untreated paper the desired word or symbol, so that when it is immersed or otherwise treated with water, the paper will absorb it into the body of the paper making it more translucent than the area not so treated, thereby making visible the desired insignia.
I accomplished this by immersion of the paper into a solution that will permanently reduce the surface tension of the sizing to the desired extent and cause the solution to penetrate into the body of the paper by pressure of a roll engraved with characters that it is desired to produce which will be invisible when the paper is dry. The apparatus and method of producing visible characters on paper, using a solution of dye, is well known in the art and is amply described in the patent issuedto LaMonte, No. 123,782, dated February 20, l872,'and others.
The solution used for this purpose may be varied to any 'extent to conform with the nature of the paper, the amount of pressure andthe construction of the machine. I find that a mixture of 10% solution of borax and a 5% solution of tribaslo sodium phosphate, equal parts of each,
is generally satisfactory for this purpose but to securea moreperfect result, I add one quarter of 1% of the sodium salt of the sulphuric acid ester of lauryl alcohol which accelerates and greatly augmentsthe destruction of the sizing where the 1 paper is impressed'with-the desired characters.
" The paper, after beingimpressed with the desired characters, may be run through-a set of squeeze rolls to remove the surplus solutionand dried; or the surplus solution may be removed by immersion in water, the surplus water being squeezed out and the paper then dried; or any variation that may be indicated by the nature of the'sizing effect of the paper, the exact details being obvious to those skilled in this'art.
After this paper is dried, the sizing effectber tween the marked and unmarked areas is so dis-- turbed and alteredthat upon the application of water or immersion in that liquid, thecharacters will absorb more than the ground, making them plainly discernible, although the operation, when skillfully done, does not alter the appearance. After the characters have been developed by such means, the paper may be dried when they will disappear and can be redeveloped; at any time by immersion or otherwise applying water in the or characters will absorb the ink selectively so that the identifying words or characters no longer disappear, an indication that the label has been developed.
To accomplish this effect in a more thorough manner, I may incorporate in the solutions a substance that acts as a mordant for the color that would be used for printing the label or I may coat the back with interacting chemicals, such as on one side iron salt and on the other a prussiate, which chemicals being separated by an insulating membrane of the paper do not interact until the paper is wet, when they will, and produce a significant color selectively in the letters or design originally produced in the paper by the process outlined.
I am aware that paper has been treated to disturb the sizing effect so as to produce words or designs upon the application of water but I am not aware, before my invention, of the production of words or designs in the manner described; I am not aware of the incorporation of reactive chemicals on opposite sides of a paper when the' sizing effect has been disturbed in the manner outlined, or in any other way, so that upon the ap-. Y
plication of water, the disturbed sizing efiect will admit of the production by reason of the combination of said chemicals of a word or design for the'purpose outlined.
I do notlimit the scope of this invention to the specific materials described or to use water in producing this effect. I may use alcohol or other liquids in combination with paper that has a sizing effect that may be selectively destroyed by the method I have described. The essential feature of this invention is the selective destruc tion of the sizing effect by causing more of the active material to enter into the paper and de-- stroy the sizing effect wherein impressed while wet with said solution.
It is not essential that the selective destruction I of sizing effect in this manner be renderedgvisible by water. The active bath may be so designed that it will cause the words, characters or designs to appear when moistened with oils or. other liquids.
1. A distinctive paper having hidden words, characters or designs formed by selectivevariation in the sizing effect, coated on opposite sides with interacting chemicals adapted to develop and render permanently visible said words, characters or designs when said paper is wet with a liquid.
2. The method of producing a distinctive paper which consists in first subjecting a dry sized paper stock to the action of a colorless liquid capable of modifying the surface sizing of the paper, then impressing said paper stock, while wet with the said liquid, with a member engraved with predetermined indicia to selectively increase the penetration of said liquid and the said modification of the sized surface thereby at the impressed areas to form normally invisible markings, and thereafter drying said paper stock, whereby when paper is moistened said markings are rendered visibly distinct from the unimpressed area.
pressed areas to form normally invisible markings, and thereafter drying said paper stock; and printing thereon a visible indicia with a permanentink adapted to be removed by abrasive treat- 'ment of said paper to afford a warning of attempted erasure of any subject matter inscribed on said paper. I 1
4. The methodsof producing a distinctive paper which consists in first subjecting a dry sized paper stock to the action of a colorless liquid capable ofmodifying the surface sizing of the paper, then impressing said paper stock, while wet with the said liquid, with a member engraved with predetermined indicia to selectively increase the penetrationof said liquidand the said modification of the sized surface thereby at the impressed areas to form normally invisible markings, and
- thereafter drying said paper stock; and printing .thereon a visible design or other subject matter with asensitivewater soluble ink, whereby when said paper is moistened the sensitive ink is absorbed by said modifications in the sized surface of said paper to permanently mark the same and afford a visible warning that said paper has once been developed. a
BURGESS W-. SMITH.