US2555474A - Safety ink - Google Patents
Safety ink Download PDFInfo
- Publication number
- US2555474A US2555474A US31201A US3120148A US2555474A US 2555474 A US2555474 A US 2555474A US 31201 A US31201 A US 31201A US 3120148 A US3120148 A US 3120148A US 2555474 A US2555474 A US 2555474A
- Authority
- US
- United States
- Prior art keywords
- ink
- cobaltous chloride
- solution
- dye
- safety ink
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D11/00—Inks
- C09D11/16—Writing inks
Definitions
- This invention relates to inks for writing, stamping or printing documents and the like. It is one object of the invention to provide an ink of such a nature that alteration of a document in which such ink is used is made exceedingly diificult without easy detection.
- an ink is provided which is a mixture of two or more compatible constituents, one of which gives the ink a well-defined color but can be attacked by one or another of the oxidizing or bleaching reagents usually employed to bleach or fade ink.
- the other constituents are water-soluble substances which are normally colorless or nearly so but which take on a permanent color, preferably of a deep hue, when treated with any of the oxidizing or bleaching reagents usually resorted to as eradicators.
- any attempt to bleach or fade a portion of it for the purpose of efi-ecting a secret alteration results in the development of a latent color conspicuously differing from the original.
- an aniline dye may be employed; for example, methylene blue, methyl violet or malachite green.
- a solution of a soluble diamino-diphenyl such as benzidine dihydrochloride.
- This substance is colorless in solution but when treated with a bleaching reagent, turns a bright red which is inert to almost all the ordinary laboratory reagents but may be considerably bleached by potassium permanganate followed by sodium bisulphite.
- a salt of cobalt is included in the ink; for example, cobaltous chloride is soluble and is but slightly colored when in solution. The cobalt salt is turned black by sodium bisulphite.
- a Writing fluid consisting of a mixture of aqueous solutions of an aniline dye, cobaltous chloride, and benzidine dihydrochloride.
- a writing fluid consisting of a mixture of aqueous solutions of an aniline dye, cobaltous chloride and benzidine dihydrochloride in the proportion of one ounce of aniline dye in a gallon of water, one ounce of cobaltous chloride in a pint of water and one gallon of saturated aqueous solution of benzidine dihydrochloride.
Description
Patented June 5, 1951 SAFETY INK John de Vries, Boston, Mass.
No Drawing. Application June 4, 1948, Serial No. 31,201
(Cl. MIG-22) 2 Claims.
This invention, relates to inks for writing, stamping or printing documents and the like. It is one object of the invention to provide an ink of such a nature that alteration of a document in which such ink is used is made exceedingly diificult without easy detection. In preparing an ink for this purpose, it is important that the ingredients be compatible and free from any substance which would attack a pen or other writing instrument in which the ink might be employed. According to the invention, an ink is provided which is a mixture of two or more compatible constituents, one of which gives the ink a well-defined color but can be attacked by one or another of the oxidizing or bleaching reagents usually employed to bleach or fade ink. The other constituents are water-soluble substances which are normally colorless or nearly so but which take on a permanent color, preferably of a deep hue, when treated with any of the oxidizing or bleaching reagents usually resorted to as eradicators. Thus when a document has been written or printed with such ink, any attempt to bleach or fade a portion of it for the purpose of efi-ecting a secret alteration results in the development of a latent color conspicuously differing from the original.
For the original color of the ink an aniline dye may be employed; for example, methylene blue, methyl violet or malachite green. With the dye is mixed a solution of a soluble diamino-diphenyl such as benzidine dihydrochloride. This substance is colorless in solution but when treated with a bleaching reagent, turns a bright red which is inert to almost all the ordinary laboratory reagents but may be considerably bleached by potassium permanganate followed by sodium bisulphite. To take care of that exception, a salt of cobalt is included in the ink; for example, cobaltous chloride is soluble and is but slightly colored when in solution. The cobalt salt is turned black by sodium bisulphite.
The following is a specific example of an ink embodying the invention, it being understood that the proportions of the ingredients given may be varied to get different color efiects in the ink, and that in place of the substances named, other equivalent substances may be employed. In one gallon of distilled water dissolve an ounce of an aniline dye. Dissolve one ounce of. cobaltous chloride in one half pint of hot water, filter, and add the filtrate to the dye solution. Make a saturated solution of benzidine dihydrochloride in one gallon of distilled Water, add to the above mixture, and filter.
I claim:
1. A Writing fluid consisting of a mixture of aqueous solutions of an aniline dye, cobaltous chloride, and benzidine dihydrochloride.
2, A writing fluid consisting of a mixture of aqueous solutions of an aniline dye, cobaltous chloride and benzidine dihydrochloride in the proportion of one ounce of aniline dye in a gallon of water, one ounce of cobaltous chloride in a pint of water and one gallon of saturated aqueous solution of benzidine dihydrochloride.
JOHN DE VRJIES.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 46,684 Lummus Mar. '7, 1865 650,901 Kretschmann June 5, 1900 1,172,414 Weis Feb. 22, 1916 1,972,395 Sayler Sept. 4, 1934 2,200,069 Lubs et a1 Mar. '7, 1940 2,313,592 Smith Mar. 9, 1943 FOREIGN PATENTS Number Country Date 232.246 Great Britain Apr. 9, 1925
Claims (1)
1. A WRITING FLUID CONSISTING OF A MIXTURE OF AQUEOUS SOLUTIONS OF AN ANILINE DYE, COBALTOUS CHLORIDE, AND BENZIDINE DIHYDROCHLORIDE.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US31201A US2555474A (en) | 1948-06-04 | 1948-06-04 | Safety ink |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US31201A US2555474A (en) | 1948-06-04 | 1948-06-04 | Safety ink |
Publications (1)
Publication Number | Publication Date |
---|---|
US2555474A true US2555474A (en) | 1951-06-05 |
Family
ID=21858142
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US31201A Expired - Lifetime US2555474A (en) | 1948-06-04 | 1948-06-04 | Safety ink |
Country Status (1)
Country | Link |
---|---|
US (1) | US2555474A (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1064663B (en) * | 1953-03-09 | 1959-09-03 | Staedtler Fa J S | Writing paste for ballpoint pens |
US3886083A (en) * | 1974-05-09 | 1975-05-27 | American Bank Note Co | Safety inks and documents |
US5232494A (en) * | 1992-07-31 | 1993-08-03 | Binney & Smith Inc. | Color changing compositions |
US5352282A (en) * | 1992-07-31 | 1994-10-04 | Binney & Smith, Inc. | Color changing compositions |
US5460647A (en) * | 1995-02-10 | 1995-10-24 | Binney & Smith Inc. | Color-changing marking composition system |
US5464470A (en) * | 1995-02-10 | 1995-11-07 | Binney & Smith Inc. | Color-changing marking composition system |
US5478382A (en) * | 1992-07-31 | 1995-12-26 | Binney & Smith Inc. | Color changing compositions for use on non-porous surfaces |
US5486228A (en) * | 1992-07-31 | 1996-01-23 | Binney & Smith Inc. | Washable color changing compositions |
US5489331A (en) * | 1992-07-31 | 1996-02-06 | Binney & Smith Inc. | Color changing compositions using acids |
US5492558A (en) * | 1992-07-31 | 1996-02-20 | Binney & Smith Inc. | Color changing compositions for highlighters |
US5498282A (en) * | 1992-07-31 | 1996-03-12 | Binney & Smith Inc. | Color changing pan paint compositions |
US5503665A (en) * | 1992-07-31 | 1996-04-02 | Binney & Smith Inc. | Latent image compositions |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US46684A (en) * | 1865-03-07 | Improved red ink | ||
US650901A (en) * | 1899-04-20 | 1900-06-05 | Ernst Kretschmann | Paper for controllable secret writing. |
US1172414A (en) * | 1911-01-06 | 1916-02-22 | Perfect Safety Paper Co | Process of making safety-paper for checks and similar devices and the safety-paper itself. |
GB232246A (en) * | 1924-04-09 | 1925-10-15 | Todd Co Inc | Improvements in or relating to safety papers |
US1972395A (en) * | 1931-02-20 | 1934-09-04 | Parker Pen Co | Permanent brilliantly colored writing fluid |
US2200069A (en) * | 1937-01-21 | 1940-05-07 | Du Pont | Spirit printing inks and process of making same |
US2313592A (en) * | 1940-09-26 | 1943-03-09 | Todd Co Inc | Safety paper and process of preparing the same |
-
1948
- 1948-06-04 US US31201A patent/US2555474A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US46684A (en) * | 1865-03-07 | Improved red ink | ||
US650901A (en) * | 1899-04-20 | 1900-06-05 | Ernst Kretschmann | Paper for controllable secret writing. |
US1172414A (en) * | 1911-01-06 | 1916-02-22 | Perfect Safety Paper Co | Process of making safety-paper for checks and similar devices and the safety-paper itself. |
GB232246A (en) * | 1924-04-09 | 1925-10-15 | Todd Co Inc | Improvements in or relating to safety papers |
US1972395A (en) * | 1931-02-20 | 1934-09-04 | Parker Pen Co | Permanent brilliantly colored writing fluid |
US2200069A (en) * | 1937-01-21 | 1940-05-07 | Du Pont | Spirit printing inks and process of making same |
US2313592A (en) * | 1940-09-26 | 1943-03-09 | Todd Co Inc | Safety paper and process of preparing the same |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1064663B (en) * | 1953-03-09 | 1959-09-03 | Staedtler Fa J S | Writing paste for ballpoint pens |
US3886083A (en) * | 1974-05-09 | 1975-05-27 | American Bank Note Co | Safety inks and documents |
US5489331A (en) * | 1992-07-31 | 1996-02-06 | Binney & Smith Inc. | Color changing compositions using acids |
US5326388A (en) * | 1992-07-31 | 1994-07-05 | Binney & Smith Inc. | Color changing compositions |
US5352282A (en) * | 1992-07-31 | 1994-10-04 | Binney & Smith, Inc. | Color changing compositions |
US5478382A (en) * | 1992-07-31 | 1995-12-26 | Binney & Smith Inc. | Color changing compositions for use on non-porous surfaces |
US5486228A (en) * | 1992-07-31 | 1996-01-23 | Binney & Smith Inc. | Washable color changing compositions |
US5232494A (en) * | 1992-07-31 | 1993-08-03 | Binney & Smith Inc. | Color changing compositions |
US5492558A (en) * | 1992-07-31 | 1996-02-20 | Binney & Smith Inc. | Color changing compositions for highlighters |
US5498282A (en) * | 1992-07-31 | 1996-03-12 | Binney & Smith Inc. | Color changing pan paint compositions |
US5503665A (en) * | 1992-07-31 | 1996-04-02 | Binney & Smith Inc. | Latent image compositions |
US5460647A (en) * | 1995-02-10 | 1995-10-24 | Binney & Smith Inc. | Color-changing marking composition system |
US5464470A (en) * | 1995-02-10 | 1995-11-07 | Binney & Smith Inc. | Color-changing marking composition system |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2555474A (en) | Safety ink | |
US3886083A (en) | Safety inks and documents | |
JPS6223120B2 (en) | ||
EP0660860A4 (en) | Assembly or set of different color inks and an assembly of writing instruments. | |
US3884707A (en) | Printing ink and process | |
GB759157A (en) | Improvements in or relating to the production of written matter | |
US4198445A (en) | Latent image printing and development | |
US2445586A (en) | Moisture-sensitive paper and the manufacture thereof | |
US2068204A (en) | Indelible ink | |
US1514222A (en) | Method of printing documents | |
US1864116A (en) | Production of papers for security purposes | |
US1911774A (en) | Safety paper | |
US1417820A (en) | Means for rendering the alteration of documents capable of detection | |
US1421728A (en) | Method of making an indestructible black stamp dye for documents | |
DE42260C (en) | Manufacture of security paper | |
Zimmerman | Colored waterproof drawing inks | |
US1589210A (en) | Method of protecting documents | |
US2186810A (en) | Safety paper and method of making same | |
Erfurt | The Dyeing of Paper Pulp: A Practical Treatise for the Use of Papermakers, Paperstainers, Students and Others | |
Snow et al. | The chemical detection of iron used in inks | |
US3140950A (en) | Blueprint paper and coating composition including polyvinyl alcohol for making same | |
US2075538A (en) | Safety paper | |
GB695548A (en) | Improvements in or relating to means for producing colour-variable writing | |
US137775A (en) | Improvement in safety-papers for bank-notes | |
JPH01103676A (en) | Discolorable ink and matter printed therewith |