US2478070A - Developing inks - Google Patents

Description

atent ecl Aug. 2, 1949 STATES 2-,47s,o,7o--

DEvELoPINGsINKse- William H. WobdfUniversity Heights, Ohio, as signer to Harris-Seybold-Potter(inhalants Cleveland,' hio; a. corporation of- Ohiou No Drawing-e Application March-1 0,.1945,i Serial No. 582,176,, I

5 Claims.

In lithograph c developing-inksare applied-to remains on-the areas of light-hardened" colloid after development, its functionsbeing to "protect the colloid of-the image from theimoisture and etching materials usedprr the plate preparatory to and during printing, .and to maketheimage areasattractive or receptive to the ink applied by the press during printing, In accordance with the present invention, developing inks @may be had with greatly augmented,ink-attractiveness of image areas treated therewith, so that superior printing, and improved resistance of the image to attack by etching and dampening fluids is obtained. The present composition adheres also more tenaciously to the colloidal surface of the plate, and is also more repellent to aqueous solutions of gum arable when employed to protect the non image areas of the plate during storage. Other objects and advantages will appear from the following description.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter full described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In general, the invention involves a finely divided metal in a developing ink composition, and the latter may be of known suitable ingredients. Developing inks, as well-known, are not printing inks or drying compositions, but are non-drying (Research Bulletin No. 6, page 107, published by Lithographic Technical Foundation, Inc., 1945) and involve a water-repellent base material, and this may be, for instance, a fatty oil, particularly of non-drying type. and other water-repellent or fatty materials may be included for bodying and increased effectiveness, and thus, oils such as cotton seed oil, and fats such as tallow, also asphaltum, etc., may be compounded together, and all such are referred to hereinafter as watar-repellent materials. And, a pigment such as carbon black is included, also a volatile thinner, such as turpentine, and advantageously a soap, such as sodium oleate. In particular, the present invention applies in the composition a finely divided metal. The particle size may vary somewhat, and should not be so coarse as to im- 2 pair the quality Off the printing; and a small size is preferred-by reason o-fthe greater'surfaee area provided thereby; and lessen tendency to 'settle out upon standing. Materials of ecllcidaidimension's." have been" i found" particularly des'irable. While the reason for" the remarkable actior-r of developing inks containingdivided-metal is not clear; and 'I' am "not-'liriii-tin'g--thet matter to an particular" theory; "-thereis -reason' to believe that the free surfaceresidual *VEIIEHGB' of the finely dividedmetal greatlydncreases =the a-ttrac tion on the comppnents-ofithe printing-"ink subsequently used onthedevelopedplate, -and= it 7 adsorbs more completely; and has-'superior -repulsion' onthe" aqueous-dampening andetchin-g fluids which are also applied. Certain finely divided or colloidal metals may be employed, viz. lead, iron and copper, and for conciseness these are referred to hereinafter as colloidal metals from the class having a valence of 2 and consisting of copper, lead and iron." The metal may be introduced in desired amount in range for instance from about 2 to about 25 per cent of the total ink ingredients. A satisfactory amount is around 5 per cent generally.

As indicated, the water-repellent ingredients of the ink may vary considerably in their detail character, but in all cases, with the water-repellent and thinner ingredients there is incorporated the component of the finely divided metal. As an example of developing ink employing colloidal lead containing '72 per cent particles 0-15 microns in diameter and 28 per cent particles larger than 15 microns, the following is cited:

Parts by weight Cotton seed oil 35 Asphaltum 10 Tallow 5 Sodium oleate 5 Carbon black 35 Turpentine Colloidal lead 10 In general the fatty oil component may be 17-19%, asphaltum 3-8%, tallow 1-3 sodium oleate -3%, carbon black 17-19%, and turpentine 50-60%.

Some metals are somewhat more active than others, and some variation may be had also in accordance with the fineness of division of the metal. I

Other modes of applying the principle'of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A composition of matter, consisting of water-repellent lithographic developing ink incapable of firm drying, comprising an oily liquid of substantially non-drying fatty material as the principal constituent and thinner, with the addition of about 2-25 per cent of colloidal metal from the class having a valence of 2 and consisting of copper, lead and iron, r

2. A composition of matter, consisting of a water-repellent lithographic developing ink incapable of firm drying, comprising an oily liquid of substantially non-drying fatty material as the principal constituent and volatile thinner, with the addition of about 2-25 per cent of colloidal lead.

3. A composition of matter, consisting of a fatty oil water-repellent lithographic developing ink incapable of firm drying, comprising cotton seed oil 1719 per cent, asphaltum 3-8 per cent, tallow 1-3 per cent, sodium oleate /z-3 per cent, carbon black 17-19 per cent, turpentine 50-60 per cent, and about 2-25 per cent of colloidal lead.

4. A composition of matter, consisting of a water-repellent lithographic developing ink in apable of firm drying, comprising an oily liquid of substantial non-drying fatty material as the principal constituent and thinner, with the addition of about 2-25 per cent of colloidal copper.

5. A composition of matter, consisting of waterrepellent lithographic developing ink incapable of firm drying, comprising an oily liquid of substantially non-drying fatty material as the principal constituent and thinner, with the addition of about 2-25 per cent of colloidal iron.

WILLIAM H. WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,398,770 Clapp Nov. 29, 1921 1,452,445 Seideman Apr. 17, 1923 1,511,816 Marston Oct. 14, 1924 1,717,140 Brandenberger June 11, 1929 2,014,760 Dewsbury Sept. 17, 1935 2,154,866 Renck Apr. 18, 1939 2,257,595 Danielson Sept. 30, 1941 2,284,279 Greubel May 26, 1942 FOREIGN PATENTS Number Country Date 21,607 Great Britain 1894 955 Great Britain 1895 99,228 Germany June 22, 1897 OTHER REFERENCES Printing Inks, Ellis, 1940.

Printing and Litho Inks, Wolfe, 1941.

Webster's New International Dictionary, 2d edition, unabridged, 1938, Lithography, page 1443.

American Ink Maker, vol. 13, No. 4, page 31.