US2329143A - Safety paper and method of making same - Google Patents

Description

Patented Sept. 7, 1943 Burgess W. Smith. Rochester, N. Y., asslgnor to The Todd Company, Inc Rochester, N. Y., a

corporation of New York No Drawing.- Application March 25, 1941, Serial No. 385,152

14 Claims. (cl. 117-1) This invention relates to class of paper known as safety paper used for checks, drafts,.bonds, or other commercial instruments, having as its chief object the provision of advantageous paperof this character of a comparatively simple nature,

' economical to produce, and applicable to a wide trate deeply into the body of the paper so that it is not removable by abrasion.

Many prior types of paper have depended upon warning characters on the paper with a substantially colorless stain producing material.

My present invention provides a further simple'and inexpensive method of producing such paper, having various other advantages such as sharp and distinct warning words when developed with eradicators, the words forming well into the body of the paper and penetrating through tothe other side to resist removal by abrasive methods, as well as accessibility to the action of eradicating chemicals to insure rapid and thorough development of the warning color or stain, as well as being generally available for making safety paper of various kinds and styles.

the bleaching out of a fugitive over-tint with eradicators to indicate the-application of the chemical thereto. As' such protective tints may be readily restored, the more modern types of safety paper have additional compounds incorporated therein to produce a stain that inhibits successful retinting until the stain is removed. Flat stains of this nature are not ample protection as they could be explained'to those who are not aware of their significance, as a result of splashing or spilling some dark colored substance thereon. To give such developed stain significance, the active material adapted to change color with eradicators has been printed or otherwise applied so as to form latent warning words or indicia.

It is obvious that in the use of latent warning words or indicia to indicate the application of ink eradicators, they should be provided in a way to resist removal from the paper to the greatest possible degree, and especially resistant to erasure by abrasion of the paper surface. This may be accomplished by having the stain when developed penetrate as deeply as possible into the body of void because of its generally recognized signithe paper. However, it has been found diflicult to have the latent printed warning word or symbol penetrate into the body of the paper, as it is impractical to print the same with active ink and have it penetrate through the paper. This is largely due to the tendency of an ink that will penetrateto spread laterally and thereby render the warning words orindicia indistinct and il- In accordance with the present invention it has been found that these advantages may be accomplished by causing the active material to be distributed throughout the body of the paper. This may be done in the process of manuacture by adding it to the beater or incorporating it into the sizing, as is well known in the art. There are a number of active chemical materials suitable for this purpose, such as, forexample, the sodium salts of diphenol, the hydrochloride of diphenylguanidine and alpha-naphthidine. These as well as a number of other chemicals suitable for the purpose are of a nature to react upon the application of eradicatorsto the paper to assume a comparatively deep or conspicuous tint or color as well understoodin the art.

To the impregnated paper stock prepared in one of the above manners I propose to print or otherwise apply suitable warning characters or symbols with a water-resisting or water-repelling colorless masking ink or medium in any manner that is expedient. For example, it may be printed typographically from relief plates, or by rotogravure from intaglio plates. Other methods of printing will be equally suitable. While various, marks, signs, and words are adapted to be readily recognized as expressing a warning meaning are available, it is preferred to use the word forming the warning indicia penetrate into the paper to any extent, it is desirable to have it do so to some degree but not sufii'ciently for the lateral spreading to materially affect the legibility of the warning word. Such an ink may be of a colorless lithographic varnish but, it is desirable to substantially colorless stain producing material being adapted to produce a conspicuous color when acted upon by ink eradicators, and selectively reducing the activity of saidjmaterial to the reaction with eradicators at predetermined areas of the paper by printing warning words or indicia thereon with a substantially colorless masking varnish.

3. A method of making safety paper which consists in uniformly incorporating in the paper a substantially colorless stain producing material part develops the required stain. Normal application of eradicators will develop the stain on the surface leaving the word practically white. On continued orfrequent application of eradicators there may be a development underneath the warning words or indicia but at no time will the development completely obliterate all traces of the warning characters.

In an application filed on March 25, 1941, bearing Serial No. 385,153 I have described and claimed a further improved protective paper and method of making same. The paper described in my co-pending application is prepared by first modifying the surface of a finished or slack sized paper to vary or retard its penetrating qualities, and then applying the stain producing material adapted to penetrate into the untreated portions of the paper. A paper and process described in this co-pending application may be considered the reverse of that followed in the present ap-- plication.

A particular advantageous feature of my present invention resides in the fact that the background developing inhibits the removal of writing from an instrument by tracing the word with a brush or pen with an eradicator. Such methods of manipulation will not be effectual in changing the meaning of the original writing. Obviously, the stain will be developed in substantially the same form as the original writing as the paper contains sufficient reactive material to reform the writing sufficiently to be legible.

It is obvious that paper manufactured in this manner may be further protected against chemical or mechanical alteration by printing or otherwise applying a sensitive tint which may be solid or a configuration. If such an over-print is used it is not essential that the latent warning word be entirely invisible as such superimposition tends to camouflage, as well known in the art.

While the foregoing discloses a satisfactory method of practicing the present invention to roduce a paper having its penetrating qualities modified so as to admirably fulfill the purpose intended, it is not the desire to be limited in any way of practicing the invention or to any form of the resultant product, as both are capable of numerous changes and modifications all coming within the scope of the claims which follow.

I claim as my invention:

1. A method of making safety paper which consists in the initial step of uniformly incorporating in the paper a substantially colorless stain producing material being adapted to produce a conspicuous color when acted upon by an ink eradicator, and then protecting the surface of the impregnated paper at predetermined areas by the application of warning words or indicia with a substantially colorless protective medium so as to selectively reduce the activity of said material to ink eradicatorat said areas.

2. A method of making safety paper which consists in uniformly incorporating in the paper a being adapted to produce a conspicuous color when acted upon by the application of ink eradicators, and selectively reducing the activity of said material to the reaction with ink eradicator at predetermined areas of the paper by printing warning words or indlcia thereon with a substantially colorless water-resistant medium.

4. The method of making safety paper which consists in uniformly incorporating in the paper a substantially colorless material adapted to have its color conspicuously altered by the reaction with chemical eradicating means, and applying over the surface of the paper so treated in a substantially colorless protective medium being capable of varying the response of said material to eradicating means, matter adapted to inherently convey a warning upon the application of said eradicating means to the paper.

5. The method of making safety paper which consists in printing on a paper having embodied therein a substantially colorless material being adapted to produce a conspicuous color when acted upon by chemical eradicators, warning indicia in a substantially colorless protective medium to prevent said active material of the paper from being altered at the areas printed with the warning indicia upon the application of chemical eradicators tothe paper.

6. The method of making safety paper that is capable of developing warning indicia upon the application of chemical eradicators, which comprises the step of first uniformly incorporatin in the paper a substantially colorless material of a character adapted to produce a conspicuous color when acted upon by ink eradicators, and then printing warning indicia on the thus treated paper with a substantially colorless protective varnish adapted to retard said material from being altered at the printed areas upon the application of eradicator to the paper.

7. The method of making safety paper which consists in uniformly incorporating in the paper a substantially colorless material being adapted to produce a conspicuous color when acted upon by chemical eradicators, printing over the surface of the treated paper in the form of a protective medium to vary the response of said material in the paper at the printed areas to eradicators, and then overprinting said paper in relatively erasible ink, a. tint or pattern.

8. A safety paper having a substantially colorless stain producin-g material uniforml incorporated therein, said material being of a character adapted to have its color conspicuously "altered when acted upon by ink eradicating re- 9. A safety paper havinga substantially color- I less stain producing material uniformly incorporated therein and being adapted to produce a conspicuous color when acted upon by an ink printed thereon in a substantially colorless masking varnish to selectively reduce the activity of said material to ink eradicator.

10. A safety paper having uniformly incorporated therein a substantially colorless stain producing material being adapted to produce a corn spicuous color when acted uponby an ink eraditially colorless water-resisting mediumadapted to selectively reduce the activity of said material to ink eradicator.

11. A safety paper containing a colorless chemical capable of'reacting with eradicator to produce a stain, and having applied thereon a film of ethyl cellulose in the form of warning words or indicia.

eradicating means.

at predetermined areas by the application of said '13. A safety paper having a substantially colorless material uniformly embodied therein of a character to have its color conspicuously altered by'the action of chemical eradicating means, warning indicia printed in repetition thereon in a substantially colorless varnish to protect said cator, and matter printed thereon in a substana material from being altered at well defined areas upon the application of said eradicating means, and having an overprinting in sensitive ink of a 1 tiniyor pattern adapted to be removed by the substantially application of said chemical eradicating means or by mechanical erasure. I

14. A safety paper having a substantially colorless -material embodied therein of a character adapted to produce a conspicuous color when acted upon by said ink eradicator, and having the su'rfaceof the paper selectively altered by warning indicia, applied thereon with a protective medium to vary the response of said material at predetermined areas upon the application v of said eradicating means.

. BURGESS W. SMITH.