DE1812380B - . Chromogenic printing ink for the production of recording materials - Google Patents

Description

The invention relates to a normally colorless, multi-component printing ink, which causes clear markings on sensitized recording material.

The known printing inks used in color generation systems contain a liquid organic solvent, the viscosity of which is such that it acts as a carrier liquid for the printing ink and one or more colorless, basic, chromogenic dyes dissolved therein. The most advantageous, frequently used combination consists ^x of crystal violet lactone and benzoyl leucomethylene blue.

Inks of this type are composed in pens or on ribbons on door typewriters used with sensitized leaves. In the main, however, they are found in the "no coal" - Known paper, pressure-sensitive copier papers use. In a preferred use, the ink is microscopic in size Enclosed capsules, which are applied close together as a coating on a recording medium sheet are. Such a sheet gives the printing ink to a sensitized one when subjected to writing pressure Remove the lower sheet according to the writing or printing pattern. The top of the sub sheet is sensitized with at least one substance that is related to the basic chromogenic substance of the printing ink reacts acidic and causes color formation. Examples of acidic coating materials are oil-insoluble Minerals or inorganic solids in the form of small particles, e.g. B. kaolin, attapulgite, silica gel, Zeolites and the like, as well as inorganic acidic polymers. The acidic reacting inorganic substances and organic polymers can be used singly or in combination.

When creating an impression by applying colorless, basic, chromogenic printing ink up to now it has not been possible to produce physiological or spectral black on an acidic carrier receive. The invention provides a printing ink with at least two components that go together produce a black color. This is done by molecular mixing of different colors, their Absorption spectra lie in such a way that a black color results when white light is incident, whereby it It does not matter whether the acidic substance is a polymer, a mineral or a non-mineral inorganic one Substance or a combination of such acidic substances.

The invention thus relates to a normally colorless, basic, chromogenic printing ink which on contact with an acidic substance reacts with color formation, consisting of an organic Solvent in which 3,3-bis- (1-dimethylaminophenyl) -6-dimethylaminophthalide and / or 3,7-bis- (dimethylamino) -10-benzoylphenothiazine are resolved.

The invention is characterized in that 4,4'-bis- (dimethylamino) -benzophenone-N-phenylimide is also present in the solvent or 4,4'-bis (dialkylamino) benzophenone is dissolved together with any of the following: 3,3-bis (1,2-dimethylindol-3yl) phthalide; 3- (1-ethyl-1-methylindole-Syl) -3- (2-methylindole-3-yl) phthalide; 2-chloro-6-diethylamino - 3 - methylspiro [9 - H - xanthene - 9,1 '- phthalide] or 9 - diethylaminospiro [1,2 - H - benzo (a) xanthene-12,1'-phthalide].

The part of the printing ink formed by the liquid solvent must be capable of the marking-forming to dissolve chromogenic components. The solvent can be volatile or non-volatile. It can also be a solvent for only one or for several components and completely or partially volatile. Examples of volatile solvents for the basic chromogens mentioned and acidic polymeric mark-forming components are toluene, petroleum distillate, perchlorethylene and xylene. Examples of non-volatile solvents are high boiling petroleum fractions and chlorinated diphenyls.

In general, the solvent which forms the carrier liquid for the printing ink should be selected in this way be that there is at least 1 percent by weight of the basic chromogenic material, preferably more

than 2%, as well as a larger amount of the polymeric material, ie up to about 15% or more, is able to dissolve in order to cause an effective reaction. Preferably, however, the solvent should be able to contain an excess of polymeric! To dissolve the substance, so that the chromogenic substance is used as completely as possible in the event of a reaction, thereby ensuring maximum local coloration of the reaction area.
Another criterion for the solvent chosen is that it must not impair the color formation reaction. In some cases * this reaction can be negatively influenced by the solvent, for example the intensity of the colored marking can be reduced. In this case, the solvent should be so readily vaporizable that it is ensured that it disappears from the reaction site after it has brought the marking-forming components into an intimate mixture by dissolution, so that the color-forming reaction can then take place completely.

The chromogenic substances used in combination, by means of which the new type of printing ink in solution to be produced according to the invention are:

I. 3,3-bis- (I-dimethylaminophenyl) -6-dim thylaminophthalid, which immediately gives a blue color with an acidic reacting substance, but has a tendency to fade slightly in light when it is with a surface-active, solid, acidic Reactant is made to react.
II. Commercially available 4,4'-bis (dialkylamino) benzophenone which gives a yellow color.

III. A substance from the group

a) 3,3 - bis (1,2 - dimethylindol - 3yl) - phthalide;

b) 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-indol-3-yl) phthalide;

c) 2 - chloro - 6 - diethylamino - 3 - methylspiro- [9-H-xanthene-9, l '-phthalide];

d) 9 - diethylaminospiro [l, 2 - H - benzo (a) xanthene-12, l'-phthalide],

all of which make a red color.

IV. 3,7 - bis - (dimethylamino) - 10 - benzoylphenothiazine, d. i. commercially available benzoyl leucomethylene blue, which gives a blue color on contact with kaolin for several hours.

V. 4,4'-bis- (dimethylamino) -benzophenone-N-phenylimide, that gives an orange color and z. B. is produced by using the raw materials Aniline and bis- (p-dimethylaminophenyl) -methyleneimine are reacted in toluene.

The chromogenic compounds used jointly in the printing ink according to the invention can can therefore be recognized by their reaction color.

These chromogenic compounds are identified below by specifying their abovementioned Roman numerals together with a suitable acidic substance and the reaction color that occurs listed. Benzoylleucomethylene blue is used to create a later emerging blue color, where a permanent blue color reinforces a gradually fading (temporary) blue color is needed.

Colorless color formers I. II IH IV '■ V (later) kaolin none yellow Red blue orange Attapulgite temporary blue yellow Red blue orange phenol blue yellow Red none orange Silica gel temporary blue yellow Red blue orange

The black color is created by the combined appearance of blue, yellow and red.

Referring to the table, a number of black inks can be used with a particular acidic sensitizer. to obtain a desired printing color. From the Table shows that when using kaolin as the only sensitizer on the recording sheet a suitable printing ink is compound IV, d. i. Benzoyl leucomethyl blue, as the blue component must contain. Similarly, if a phenolic polymer is used as the sole sensitizer Compound I as the blue component, d. i. Crystal violet lactone can be used.

example 1

A special example of a two-component printing ink contains 2% of the basic ink Reactants I and V dissolved in a mixture of chlorinated biphenyl and saturated Hydrocarbon in a weight ratio of 2: 1.

Example 2

Another specific example of an ink containing three color forming components is out:

Component _. . ..

¹ ^ parts by weight

Basic reactant I 1,2

Basic reactant HIb ... 1,2

Basic reactant II 4.8

Mixture of chlorinated biphenyl and saturated hydrocarbon im

Ratio 2: 1 112.8

Example 4j

Another ink, but similar to that of Example 3, contains: i

Component j parts by weight

Basic reactant IJ 1,2

Basic reactant IHd ... 1,2

Basic reactant ΙΪ 4.8

Chlorinated biphenyl and saturated
Hydrocarbons in weight

ratio 2: 1 i 112.8

Some acidic substances react with all components a colorless color image body, while others react only with some of these components.

Bring to the ink on tin sensitized recording material, then the educational displays a colored marking that is missing PNER the necessary acidic substances during the occurrence of a virtually black appearing '> tag means that the required acidic substances to react with the complementary colorless Respondents are present. Some general purpose acidic substances will develop all of the dye in the novel ink while others will not.

The creation of a colored marking serves to indicate the sensitization of a sheet to negative Kind, d. that is, no general purpose acidic material is present. This negative response of one hand is to two Species useful, i.e., (a) for characterizing an ink receiving sheet as to its sensitizing potential and (b) to create colored markings upon such sensitization, during the printing ink produces black marks on fully sensitized sheets.

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Example 3

Another ink, but similar to that of Example 2, contains:

Component ". ,. ',

^h parts by weight

Basic reactant I 1,2

Basic reactant HIc ... 1,2

Basic reactant II 4.8

Mixture of chlorinated biphenyl and saturated hydrocarbon im

Ratio 2: 1 112.8

Claims (1)

Claim: Usually colorless, basic, chromogenic printing ink, which on contact with an acidic Substance reacts to form color, consisting of an organic solvent in which 3,3-bis- (1 - Dimethylaminophenyl) - 6 - dimethylaminophthalide and / or 3,7 - bis (Dimethylamine) -10-benzoylphenothiazine are dissolved, characterized in that in the solvent also 4,4'-bis (dimethylamino) benzophenone-N-phenylimide or 4,4'-bis (dialkylamino) - benzophenone is dissolved together with any of the following: 3,3-bis (1,2-dimethylindol-3yl) phthalide; 3- (1-Ethyl-2-methylindol-3yl) -3 - (2-methylindole-3yl) phthalide; 2 - chlorine-6 - diethylamino - 3 - methylspiro [9 - H - xanthene-9,1'-phthalide] or 9-diethylaminospiro [1,2-H-benzo (a) xanthene-12,1 '-phthalide].