DE2802195B2 - ink - Google Patents

Description

The invention relates to an ink which contains color bases which are digested with acid in an aqueous medium contains.

Through the use of basic dyes in writing inks, especially the colors black and blue and green, the authenticity of such inks can be increased considerably. This is especially true for the Use of a basic phthalocyanine dye. Furthermore, the use of such plays basic Dye combinations in the manufacture of inks therefore play a special role, as they are based on particularly deep black tones can be achieved on the paper.

Because they are largely insoluble in water, the basic dyes must be digested. when it comes down to solving them in aqueous inks. This requirement exists in particular for inks that are used in writing implements where the application tip or the actual writing organ has capillary structure. In such cases, the dyes would predominate are present as pigments in the aqueous ink liquid, this would lead to a blockage of the capillaries, especially with fine line writing implements, which ultimately lead to the writing implements being unusable would.

So far, the digestion of color bases used in aqueous inks has been carried out, of which only here for example Victoria blue, methyl violet, K: istall violet, Chrysoidine, rhodamine, auramine, nigrosine and especially the derivatives of phthalocyanine be mentioned, in a relatively strongly acidic aqueous medium (pH value between 2.2 and 4.0) by means of relatively strong acids such as hydrochloric acid and acetic acid. The Dissolution of the dye as a result of the formation of the corresponding salts (hydrochlorides, acetates) or es such colored salts were used from the outset with any necessary addition of such Acids to increase water solubility.

Due to the pH value, which is relatively far in the acidic range, this resulted from its use such inks adversely affect the metallic Parts of the writing instrument with which the ink comes into contact due to corrosive influences. Such parts include, for example, the holders for the writing tip, which are mostly made of brass. In addition, carboxylic acids used in the manufacture of the ink or formed with them Color salts of the basic dyes in a medium with a low pH value volatile carboxylic acids split off on metal parts even where there is no direct wetting by the ink can cause severe corrosion.

Accordingly, the invention is based on the object of breaking down the basic dyes for their use in aqueous inks in such a way that the ink liquid no longer has any corrosive effects on metal parts or at least largely reduces such influences compared to the use of the known inks are.
The solution to the problem of the invention is that

»O the color bases with an amino acid or mixtures are unlocked by amino acids, with the amino acids having up to 6 carbon atoms and up to 3 Have amino groups.

For the purposes of the invention can be both acidic

2ί reactive as well as neutral and basic amino acids can be used. Examples are: glycine, alanine, serine, threonine, valine, leucine, aspartic acid, Glutamic acid, arginine, lysine, ornithine and others. There is thus also the use of amino acids with

ίο several COOH groups and / or NH2 groups in the Scope of invention. The amino acids used according to the invention can be straight-chain or branched.

In the practice of the invention, dye bases of the conventional type, some of which above Examples were given, as well as derivatives of phthalocyanine in for the color effect of the ink sufficient amount to be brought into aqueous solution. Surprisingly, the pH of the ink liquid to a value above

· Set »<> 4.0, preferably 4.5. It is even possible that The pH value should be close to the neutral point, possibly even in the alkaline range, which is good for the Prevention of corrosion on metal parts is of particular advantage. The achievable with the invention

■ fj effect must therefore be particularly surprising be considered because the salts of color bases with carboxylic acids described in the prior art are water-insoluble at pH values above 4.0. Above all, it was not foreseeable that at

"> '> Use of phthalocyanine color bases with amino acids a digestion would be possible, which would allow the adjustment of a pH value of the ink in the vicinity of the Ncutralpunktes allows, after these color bases have so far always been digested in a strongly acidic medium

■> ^r > had to.

With the invention, particularly good results can be achieved when using ornithine, it is also possible to add aspartic acid to the dye solution. This results in

^h "pl 1 values greater than 7.0.

To improve the properties of the ink according to the invention, the usual ones can of course also be used Co-formulants, such as, for example, Feuchthaltcmittcl and Nci / initiel, can be added.

^<Λ Preferred use is the inventive-Bc ink at .Sehreibgeräten with capillary Auftragsspitzc.
Below are some compositions of

Inks according to the invention described as embodiments of the invention.

example

Blue ink

0.5 Dye C. I. Solvent Blue 2, Item 42 563 B 1.0 Dyes. I. Solvent Blue 51, No. 74 0.6 glutamic acid 0.2 nonylphenol polyglycol ether 25.0 diethylene glycol 72.7 water

Example 3 Black ink

0.5 C.I. Direct Blue 86, No. 74 dye 2.0 Methyl Violet Base (Color Index No. 42 553 B) 3.0 C. I. Basic Yellow 21 0.5 rhodamine base (Color Index No. 45 170 B) 1.5 amino acid I (L-aspartic acid) 1.5 amino acid II (L-ornithine) 0.2 nonylphenol polyglycol ether 25.0 diethylene glycol 65.8 water

100.0
pH value: 4.45

Green ink

Example 2

0.2 dyes. I. Solvent Blue 2, No 42 563 B.

0.8 auramine base (Beilstein E II 14: 58)

0.7 glutamic acid

25.0 diethylene glycol

73.3 water

100.0

pH value: 4.49 100.0
pH value: 7.83

Example 4

Black ink

2.0 methyl violet base (Color Index No. 42 535 B) 0.8 chrysoidin base (cf. Beilstein EII16: 203 and

Römpps-Chemie- Lexikon) 0.4 Malachite green (Color Index No. 42 000 B) 0.3 auramine base (see Römpps Chemie-Lexikon and

Beilstein E II14: 58) 6.0 L-aspartic acid 0.2 nonylphenol polyglycol ether 25.0 diethylene glycol 65.3 water

ίο 100.0

pH value: 4.51

Claims (3)

Patent claims: 1. Ink which, in an aqueous medium, contains one or more acid-digested color bases contains, characterized in that the color bases with an amino acid or mixtures are unlocked by amino acids, the amino acids 2 to 6 carbon atoms and up to 3 Have amino groups. 2. T! Nte according to claim 1, characterized in that that the color base is a derivative of phthalocyanine- ■ 3. Use of an ink according to claim 1 in writing implements with a capillary applicator tip.