US2070278A - Printing ink - Google Patents

Description

Patented Feb. 9, 1937 UNITED STATES PATENT OFFICE No Drawing. Application May 20, 1935, Serial No. 22,437

10 Claims.

copending application Serial No. 711,229, Patent Among the objects of this invention are those of producing an ink which has an excellent printability, which is quick drying, which will not skin or dry in the fountain, and which, upon operating the press after the press has been left standing, will plasticize or make printable the ink which has dried on the plate and rollers.

It is also an object of this invention to produce an ink in which the coloring matter may be either or both pigments and dyes.

In printing upon paper or other types of printable surfaces, such as for example, paper which may be used for wrapping bread, it is desirable to combine into a continuous operation the printing upon the paper web and the winding of the same into a roll. In so doing it is desirable that the ink should be dry before the web is wound into a roll otherwise the ink on the printed surface will ofiset on to the unprinted surface which contacts with the same. To expedite the printing and rolling operation the printed web is usually subjected to heat of a degree higher than room temperature. The temperature necessary to completely evaporate the liquid and solvents in the ink will be governed to a great extent by the speed of the press and the fact that it is not desirable to subject the paper to heat of such a high temperature that the moisture in the paper is evaporated or driven oil. The evaporation of the moisture in the paper causes the same to become brittle and impairs the utility of the It is an object of this invention to produce an ink that is quick drying and which, after being applied to the printable surface, will not cause sticking of one printed sheet or layer to another.

This invention also contemplates an ink that will not smear during the slipping incident to the early stages of winding or rolling the printed web.

Another important feature of this ink is that upon being applied to the printable surface it leaves no residual odor; This permits the printed finished work to be used immediately without airing and rewinding which is the common practice with inks that dry by oxidation.

The improvements in the ink which comprises this invention over that described and claimed in my copending application reside in the following factors: (1) The drying temperature range has been appreciably lowered thus permitting higher printing press speeds. (2) The introduction of higher viscosity cellulose esters. (3) The introduction of dyes as well as pigments and the combination of pigments and dyes for coloring matter. (4) The inclusion of the esters and ethers of ethylene and diethylene glycol as solvents and diluents. (5) The inclusion of elecresin esters and alkyd resins as vehicles and lubricants.

The temperature range for drying this ink may vary from 150 F. at very low press speeds where the printed web travels in the neighborhood of about to feet per minute and the ink has approximately about 11 or 12 seconds to dry, to a point where the paper scorches which will probably be around 325 F. The most eflicient drying temperature range for the present ink appears to be from 220 to 260 F. when the press speeds range from a low speed of 250 feet per minute upwards to a relatively high speed of 500 feet per minute. Satisfactory printing operations have been performed with this ink where the drying temperature ranged from F. upwards to the scorching point of the paper and the press speed ranged from '75 to 500 feet per minute.

The rate at which the ink will dry depends upon several variable factors such as temperature, the speed at which the printed web travels, the time period of contact with the heating roll, the thickness of the paper where the heat is applied by means of a roll to the underside of the printed paper or web, and the method or apparatus used for heating the printed ink. This ink dried very eificiently when applied to a sulphide paper web approximately .004 of an inch thick where the printed web was heated by being passed over a heating roll at 240 F. so that the underside or non-printed side of the paper contacted with the heating roll for a period of two and one-half to three seconds.

As a binder a cellulose ester is used. This cellulose ester may be nitrocellulose or cellulose acetate or a combination of both. The viscosity of the nitrocellulose or the cellulose ester may range from onefourth second to forty seconds. The proportion of nitrocellulose or cellulose acetate binder, figured on a dry basis by weight, should not be less than 3% nor more than 18% of the total. Excellent inks are produced with nitrocellulose as a binder where the nitrocellulose content ranges from 6% to 12%. However, as above stated, this range may be from 3% to 18%.

The alkyd resins may be used alone or may be hydrocarbons and fatty acid esters.

modifledwith fatty acids or resin acids such as gum resin and ester gum.

As a vehicle and lubricant for the pigment carnauba wax may be used as specified in my Patent 2,002,537. However, the use of resins is preferred. Two types of resins may be used, namely: (1) oleo resin esters which includes esterified dammar, elemi, balsams, and colophony, and (2) alkyd resins which are glycerol phthalates. The preferable resin content ranges from 12% to 25% of the total by weight of the finished ink, but satisfactory ink can be manufactured with a resin content ranging from 1% to 50%.

As a solvent and diluent glycol derivatives are used. These glycol derivatives are esters or ethers of either ethylene glycol or diethylene glycol. Preferably these glycol derivatives are used alone as solvents and diluents. However, these glycol derivatives may be used in combination with one or more of the benzene hydrocarbons such as benzene, toluene, xylene, or even higher fractions. These glycol derivatives may also be used in combination with some fatty acid esters such as the acetates of methyl, ethyl, propyl, butyl, or amyl alcohols. The glycol derivatives may also be used in combination with the benzene However, preferably the glycol derivatives are used alone.

Among the glycol derivatives which may be used are the following:

Ethylene glycol (Cellosolve) mono-ethyl ether E t h yl e n e g 1 yo 0] (Butyl cellosolve) mono-butyl ether E t h y l e n e g l y c 01 (Cellosolve acetate) mono ethyl e t her acetate Diethylene glycol mono -methyl ether acetate Diethylene glycol mono methyl ether Diethylene glycol mono ethyl e t h e r acetate Diethylene glycol mono-ethyl ether Diethylene glycol mono-butyl ether The concentration of these solvents and diluents can range from 40% to of the total by weight. The exact concentration of the solvent and diluent will, of course, vary within this range depending upon the kind of ink desired.

As a coloring matter pigments, dyes, and the combination of pigments and dyes are used. Among the dyes that can be used in any dye which can be dissolved in the above-mentioned solvents such as methyl violet, malachite green, Victoria blue, methylene blue, rhodamine. A dye concentration as high as 15% by weight of the finished ink may be used. However, a dye concentration not greater than 10% by weight of the finished ink is preferable in vmany cases. When the coloring matter consists of a pigment, the pigment figured on a dry basis may range from 5% to 65% by weight of the ink. When a filler is used in addition to the coloring pigment, then the total of the filler and the pigment should be'held within this range.

These various ingredients may be mixed in any of the well-known ways, such as in a paddle agitator or in a rolling mill. In some cases where (Methyl carbitol acetate) (Methyl carbitol) (Carbitol acetate) (Carbitol) (Butyl carbitol) the coloring matter consists of a dye and no coloring pigment or filler is used, the ink may be satisfactorily mixed in a paddle agitator and the passing of the mix through a grinding mill is unnecessary.

Carnauba wax may be used in place of the resins. In such case the above-mentioned glycol derivatives may be used as solvents and diluents or, if desired, ethylene glycol may be used as a solvent.

I claim:

1. A printing ink consisting of coloring matter, 3% to 18 by weight of a cellulose ester ranging in viscosity from one-fourth second to forty seconds, 1% to 50% of an oleo resin ester, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

2. A printing ink consisting of coloring matter, 3% to 18% by weight of a cellulose ester ranging in viscosity from one-fourth second to forty seconds, 1% to 50% of an alkyd resin, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

3. A printing ink consisting of coloring matter, 3% to 18% by weight of a cellulose ester ranging in viscosity from one-fourth second to forty seconds, 12% to 25% of an oleo resin ester from the group consisting of esterified dammar, elemi, balsams, or colophony, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

4. A printing ink consisting of a spirit or oil soluble dye, soluble in a glycol derivative, from the group consisting of methyl violet, malachite green, Victoria blue, methylene blue, and rhodamine, 3% to 18% by weight of a cellulose ester ranging in viscosity from one-fourth second to forty seconds, 1% to 50% of a resin, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

5. A printing ink consisting by weight of coloring matter from 5% to 65% of dry pigment, 3% to 18% cellulose ester ranging in viscosity from one-fourth second to forty seconds, 1% to 50% resin from the group consisting of oleo resin esters and alkyd resins, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

6. A printing ink consisting by weight of coloring matter of not more than 15% dye soluble in a glycol derivative, 3% to 18% cellulose ester ranging in viscosity from one-fourth second to forty seconds, 1% to 50% resin from the group consisting of oleo resin esters and alkyd resins, and 40% to 90% of a glycol derivative from the class consisting of the esters and ethers of ethylene glycol and diethylene glycol.

7. A printing ink which is quick drying at a temperature range from F. to 325 F., consisting of coloring matter, 3% to 18% by weight of a cellulose ester of the group consisting of nitrocellulose and cellulose acetate ranging in viscosity from one-fourth second to forty seconds, 1% to 50% of a resin from the group consisting of oleo resin esters and alkyd resins, and 40% to 90% of a glycol derivative from the group consisting of the esters and ethers of ethylene glycol and diethylene glycol.

8. A printing ink which is quick drying at a temperature range from 150 F. to 325 F., c

sisting of coloring matter, a. cellulose ester of the group consisting of nitrocellulose and cellulose acetate ranging in viscosity from one-fourth second to. forty seconds and comprising from 3% to 18% by weight of the finished ink, a resin from the group consisting of oleo resin esters and alkyd resins comprising by weight from 1% to 50% of the finished ink, and a glycol derivative from the group consisting of the esters and ethers of ethylene glycol and diethylene glycol comprising from to 90% of the finished ink.

9. A printing ink which is quick drying at a temperature range from 150 F. to 325 F., consisting of coloring matter, a. cellulose ester of the group consisting of nitrocellulose and cellulose acetate ranging in viscosity from one-fourth second to forty seconds and comprising from 6% to 12% by weight of the finished ink, a resin from the group consisting of oleo resin esters and alkyd resins comprising by weight from 12% to cosity from one-fourth second to forty seconds and comprising'trom 3% to 18% by weight of the finished ink, a resin from the group consisting of oleo resin esters and alkyd resins comprising by weight from 1% to of the finished ink,

and a glycol derivative from the group consisting of the esters and ethers of ethylene glycol and diethylene glycol comprising from 40% to of the finished ink.

EUGENE J. KELLY. Q0