US1646391A - Copy-pad composition - Google Patents

Description

Patented Oct. 25, 1927.

UNITED STATES PATENT OFFICE.

SANTINO cossm, or NEW YORK, AND ALFREDO TRIUNFO, or CORONA, New YORK.

COPY-PAD COMPOSITION.

No Drawing.

This invent-ion relates to compositions for copying pads, such as are used in making copies of written or printed matter. As such pads are customarily used, the matter to be copied is writ-ten or printed in copying ink on a sheet of paper and the sheet is then placed face down on the pad and pressed against the pad. In this manner ink is transferred from the sheet to the pad and when the sheet is removed an imprint of the writing is left on the pad. To make copies, sheets of blank paper are then pressed against the face of the pad, thereby transferring some of the ink of the pad to the blank paper, and when this paper is removed the copy of the original writing appears thereon.

Compositions of this character heretofore employed have generally included as their principal ingredients either gelatine or insoluble silicates, such as clays or talc, which silicates are generally mixed with some liquid so as to form a plastic or putty-like composition.

Compositions employing gelatine have the disadvantage that in hot weather they must be kept cool as otherwise they will become too soft and sticky to use. Furthermore unless the pad is used within a short time after the ink is applied, the writing or printing on the pad becomes so blurred that sat isfactory copies cannot be made. Also the ink applied to gelatine pads penetrates a considerable distance below the surface of the pad and when the pad is washed off with a sponge to remove the ink it is usually necessary to remove approximately one quarter inch from the face of the pad before the pad is sufliciently clean to be used again.

Copying compositions which contain considerable proportions of silicates or argillaceous materials have also proved generally unsatisfactory. Such materials are usually quite heavy and are not easily made nor do they form a composition of proper density for satisfactory use. The ink tends to spread on such compositions and these compositions, which dry rapidly, become, when dry, hard Application filed October 7, 1926. Serial No. 140,210.

and caked. When attempts have been made to remedy the defects which are inherent in this class of materials, by combining with the silicates or clays other ingredients, the resulting compositions have been expensive and diflicult to prepare and have not proved satisfactory in use.

Applicants have discovered that a mixture of calcium carbonate and glycerine forms a highly satisfactory copying composition provided the calcium carbonate is amorphous, preferably in the form of chalk and is finely divided and freed from impurities. We find that whiting is a satisfactory form of calcium to use. In forming the composition, the chalk and glycerine are thoroughly mixed to form a firm plastic mass of putty-like consistency which may be rolled or otherwise shaped to form a pad. As soon as made the composition is ready for use. It receives the ink impression from the original written or printed sheet without blotting and can be used to make a large number of clear copies. The ink imprint on the composition pad can easily be removed witha wet cloth or sponge and the cleaning of the pad in this manner removes a minimum of the composition from the 5 face of thepad. The composition retains its moistcondition for a long time and when drydoes not cake nor harden and can easily be moistened by a sponge wet with water or glycerine.

Having described our invention what we claim and desire to secure by Letters Patcut is:

1. A composition for copying pads consisting of glycerine and finely divided amorphous calcium carbonate.

2. A composition for copying pads consisting of glycerine and finely divided chalk.

3. A composition for copying pads consisting of glycerine and whiting.

In testimony whereof we afiix our signatures.

SANTINO COSSIA. ALFREDO TRIUNFO.