US1535861A - Safety paper and process of making the same - Google Patents

Description

Patented Apr. 28, 1925.

UNITED STATES CHARLES FRANK SAMMET, F DALTON, MASSACHUSETTS, ASSIGNQR TO CRANE &

I 1,535,861 PATENT OFFICE." v

COMPANY, or DALTON, mssacnusn'r'rs, A ran'rnnnsnrr'.

SAFETY PAPER AND rnocnss or MAKING HE SAME No Drawing.

To all whom it may concern:

Be it known that I, CHARLES FRANK SAM- MET, a citizen of the United States, residing at Dalton, in the county of Berkshire, .State of Massachusetts, have invented certain new and useful Improvements in Safety Paper and Processes of Making the Same, of which'the following is a description.

My invention relates to an improved process for the manufacture of safety pa er for checks, notes, bonds, wills and ot er documents, and has for its object the pro ductionof a paper of such character that any attempt to obliterate or remove writing, printing or other marks thereon by chemical means will cause a marked change in the appearance or color of the paper where the chemical has been brought in contact with the surface, as a result of which changes in the Writing or printing or othermarks will be more apparent and the fraud easily detected.

It will also be understood that the invention is applicable either to plain white or tinted paper, as well asrto paper having surface markin s thereon for the purpose of indicating w en mechanical erasures of the writing or marking thereon have been made.

In the manufacture of this safety paper by incorporation of the ingredients applied thereto in the body of the paper, I make use of any of the usual well-known processes for the manufacture of paper, and the material to be used in the process for making the safety paper and for the purpose of accomplishing the result, is incorporated in the paper at any desirable stage of the manufactureeither while the paper is in the pulp stage; on the web; or the material 'may be added during the sizing operation.

The essential feature of the invention con sists in the incorporation therewith at any desirable stage in the manufacture of the paper of a member of the benzidine group, such as benzidine or its,.homologues,substitution products, derivatives or salts. Of this I prefer benzidine, ortho-tolidin and orthodianisidine, and I find the most useful to be an insoluble salt of benzidine and of these I )refer the sulphate.

Vhile, as above stated, the safety material may be incorporated with the paper at any suitable stage in its manufacturethat is, in

Application filed October 31, 1921. Serial at. 511,808.

the pulp, in the web, after or with the sizing-it will also be understood that it may be applied as a coating to the otherwise finished paper; or,when desired, it may be applied by incorporating it with the ink used for marking the paper. I also consider the invention broad enough to include the application of the safety material to the finished paper either in the form of. a powder or suspended in a liquid or as a solution. In fact, in a co-pending application Serial No. 511,510, executed of even date herewith, I have set forth a way of applying the material to the finished paper by molding the material in the form of sticks somewhat analogous in size and shape of the well known sticks of shaving soap, the molding being accomplished under pressure or by incorporating a small amount of binder, such as starch, with the material sufficient to hold the particles together. This stick may be rubbed over the paper manually with the exertion of slight pressure and the excess ma terial may then be removed either by blowing or dusting it ofl. A sufiicient amount will remain incorporated in the surface of the paper to produce the desired result.

When the paper is manufactured'by incorporation of the safety material during the process of manufacture of such paper, I have found substantially the following proortions give the best results, viz: 100 parts y weightof pulp to parts of the benzidine salt, although it will be understood that these proportions may be varied without departing from the spirit of-the invention.

The substances of the class named, and es pecially those substances mentioned, are discolored upon treatment with ink eradicators, which usually contain oxidizing agents, the change being due to the oxidizing effect of the eradicator, although other ingredients thereof may also produce a color change in the safety material. A dirty brown spot is usually produced upon the paper with which they are in contact, which spot cannot be obliterated by treatment with acids, alkalis, reducingagents or other chemicals.

I have found that the safety substances I propose to use are best used in the form of insoluble salts, for example, as sulphates, since the color of the benzidine or other sulphate or other insoluble salts are practically unaffected by long exposure to light, while the soluble salts are somewhat darkened by long exposure thereto.

The stain produced by treatment with an oxidizing agent cannot be removed by treatment with acids or alkalis or reducing agents; however, should a reducing agent be present during the treatment with an oxidizing agent the stain may not appear until the reducing agent has been oxidized. v

I use the variety of tolidin and dianisidine sold as such upon the market and believe these to have the ortho-structme.

In a co-pendihg application Serial No. 511,809, designated as Case II, I have claimed the process of making safety paper and the product itself having diphenylamin incorporated therewith, and the application heretofore referred to as relating to the stick of safety material is designated as Case III, Serial No. 511,810.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is: e

1. The process of making safety paper which consists in adding to the paper a material which is a colorless member of the benzidine group or its homologues.

2. The process of making safety paper which consists in adding to the paper a salt 0% the benzidine group or homologues there- 0 3. The process of making safety paper which consists in adding to the paper an insoluble salt of benzidine.

4. The process of making safety paper whichconsists in adding to the paper benzidine sulphate.

5. The process of making safety paper which consists in adding to the paper benzidine sulphate in substantially the following prop0rtions100 parts by weight of pulp to 5 parts by weight of benzidine salt. 6. Paper, having a colorless member of the benzidine group incorporated therewith. 7. Paper, having a colorless member of the benzidine group incorporated therein.

8. Paper, having a salt of a member of the benzidine group incorporated therewith. 9. Paper, having a salt of a member of the benzidine group incorporated therein.

10. Paper, having an insoluble salt of a member of the benzidine group incorporated therewith.

11. Paper, having an insoluble salt of a member of the benzidine group incorporated therein.

. 12. Paper, having an insoluble compound of a member of the benzidine group incorporated therewith.

13. Paper, having an insoluble compound of a member of the benzidine group incorporated therein.

14. Paper, having a sulphate of a member of the benzidine group incorporated therewith.

15. Paper, having a sulphate of a mem ber of the benzidine group incorporated therein.

16. Paper, having benzidine incorporated therewith.

17. Paper, having benzidine incorporated therein.

18. Paper, having a salt of benzidine incorporated therewith.

19. Paper, having a salt of benzidine incorporated therein.

20. Paper, having an insoluble compound of benzidine incorporated therewith.

21. Paper, having an insoluble compound of benzidine incorporated therein. I

.22. Paper, having an insoluble salt of benzidine incorporated therewith.

23. Paper, having an insoluble salt of benzidine incorporated therein.

24. Paper, having benzidine sulphate incorporated therewith.

25. Paper, having benzidine sulphate incorporated therein.

In testimony whereof, I afiix my signature.

CHARLES FRANK SAMMET.