DE1644472B - - Google Patents

Description

3. Use of rhodamine dyes of the formula given in claim 1 or 2 for Production of printing and stamping inks, marking inks, ballpoint pen pastes and transparent varnishes.

Rhodamine dyes are popular because of their high color strength and brilliance excellent For the production of printing inks, stamping inks, and marking inks Ballpoint pen pastes or z. B. also suitable for coloring transparent varnishes. Since the usually but used rhodamine dye chlorides or sulfates except in alcohols and glycols are very soluble in water, have dyeings, prints or lettering produced with them generally only poor water fastness. When used in flexographic printing inks, one can use Improvement of the water fastness Auxiliary materials such as laking agents or fixing acidic resins. Laking agents are, for example, higher molecular weight organic acids. For numerous other uses, e.g. B. in the production of Ballpoint pen pastes, glycol printing inks for moisture set printing or transparent varnishes are, however the addition of such auxiliaries is not possible, so that the waterfastness of the dyeings is very often poor.

In addition, the commercially available salts of rhodamine dyes. so the chlorides or suI-

45

50

60 rod, sometimes only have moderate solubility in alcohols and glycols, which often makes the production of highly concentrated solutions, which should be stable even after prolonged storage, impossible. Another disadvantage of chlorides and sulfates is their very marked corrosive effect on metal parts of storage vessels and processing machines.

It has now been found that rhodamine oils of the general formula

H ₅ C ₂ -N

C ₂ H ₅

COOR

in which R is a hydrogen atom, a methyl or ethyl group, R _{1 is} a hydrogen atom or an ethyl group, R _{2 is} a hydrogen atom or a methyl group and X ° is an H ₂ BO ₃ -, HCO ^ - or H ₂ POj anion, in Are sparingly soluble or insoluble in water and do not have the disadvantages outlined or only to a small extent. The dye of the formula given above, in which R is a methyl group, R _{1 is} a hydrogen atom, R _{2 is} a methyl group and X ° is an HCO ₃ anion, is of particular technical interest.

It was surprising that the new rhodamine salts are sparingly or insoluble in water, although the alkali salts with these anions, like the chlorides or sulfates, are easily soluble. As a result their poor solubility in water and the simultaneously improved solubility in alcohols, such as methanol, Ethanol, propanol or benzyl alcohol, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, Propylene glycol or dipropylene glycol, glycol mono- or dialkyl ethers, aryl ethers and polyglycol ethers, the new dyes are particularly suitable for the areas of application mentioned at the beginning. she can also be used to produce highly concentrated solutions that are stable on storage z. B. usable as stock solutions for the preparation of printing inks, stamping inks or marking inks are. The corrosion effect on metal parts is with the new dyes compared to the commercially available greatly reduced.

The rhodamine dyes are produced by known methods. The following examples, in which data on parts and percentages are based on weight, provide appropriate working methods on.

example 1

10 parts of N-diethyl-m-aminophenol are heated with 12 to 13 parts of phthalic anhydride for 4 to 5 hours at 170 to 175 ° C. The still hot melt is then introduced into 70 parts of an approximately 10% strength aqueous sodium hydroxide solution and stored in the cold stirred for about 40 hours. After filtering off and washing with water, 11.5 parts are obtained Rhodamine base B, calculated on 100% product.

The moist Rhodaminbaso is Bodann in IQO parts Water dissolved hot by adding 1.5 Teilon 76% sulfuric acid and clarified by filtration, After adding 7.5 parts of boric acid under stirring at 75 ° C, it separates during cooling the metaborate. After cooling, the product is suctioned off, dried at 60 ° C. and 12.6 parts are obtained in this way green, water-insoluble rhodamine B borate.

To produce a flexographic printing ink with very good storage stability, 5 parts of rhodamine-ß-borate are used and 25 parts of shellac in 90 parts of technical-grade ethanol and 10 parts of ethylene glycol monoethylene ether dissolved at room temperature.

The water fastness of prints produced with it is better than when using the commercially available Rhod- "5 amine B chloride (C.I. 45 170) as a dye.

Example 2

10 parts of 3,6-bis- (ethylaminol ^ J-dimethyl ^ -to-carboxyphenyl-xanthene are introduced into 50 parts of methanol, and 10 parts of concentrated sulfuric acid are then added to the suspension and the mixture is refluxed for 4 to 5 hours , then the alcohol is distilled off and the residue taken up in 250 parts of hot water. It is filtered off from unreacted base at about 90 ° C and then at 60 to 70 ⁰ C 7.9 parts of concentrated phosphoric acid (85%) under Stirring is added, after which the phosphate of the rhodamine 6G methyl ester crystallizes out during cooling and is filtered off at room temperature, washed with water and dried at 80 to 90 ° C. 13 to 14 parts of the dye salt are obtained.

When using 7.9 parts of 85% phosphoric acid and ethanol instead of methanol 13 to 14 parts of 3,6-bis-ethylamino-2,7-dimethyl-9- (2'-carbäthoxyphenyl) -xanthyliumphosphals are obtained in the same way.

20 parts of the compound thus obtained, the cation of which is identical to that of rhodamine 6 G (C.I. 45 160) is, are at 90 to 95 ° C in a solution of 15 parts of a urea-formaldehyde - condensation product and 65 parts of diethylene glycol a red ballpoint pen paste. The paste has good writing properties and very good ones Storage stability.

Example 3

Dissolve 8 parts of the compound obtained according to Example 2 in a solution of 36 parts of a Phthalic acid hexanetriol ester and 54 parts of dipropylene glycol, this gives you a storage-stable glycol printing ink that is practically non-corrosive and gives waterproof prints.

Likewise, one wins from 5 parts of the rhodamine-ÖG-Äthyleslerphosphat and 25 parts of shellac by dissolving in 90 parts of technical grade ethanol and 10 parts of Äthylcnglykolmonoäthylölher Room temperature a flexographic printing ink with very good storage stability. The watertightness thus established Prints is better than when using the commercially available Rhodamine-6G-ethyl ester chloride (C. I. 45 160) won.

Similar results are obtained when using the following dyes: Rhodamine-6G-methyl ester phosphate, Rhodamine 6G ethyl ester borate and rhodamine 6 G methyl ester borate.

Example 4

The dye solution of rhodamine 6G methyl sulfate obtained according to Example 2 is, after clarification by filtration at 65 to 70 ° C., mixed in portions with 5.2 parts of sodium bicarbonate with thorough stirring. The dye precipitates out as a bicarbonate salt is filtered off, washed and dried at 7O ⁰ C. 11.5 parts of rhodamine 6 G methyl ester bicarbonate are obtained.

Analysis:

Found:

C 66.7, H 6.5, 0 21.8, N 5.2, CO ₂ 8.3,
C 66.1, H 6.6, O 22.0, N 5.3, CO ₂ 7.9;

calculated as C ₂₈ H ₃₀ N ₂ O ₆ :
C 66.2, H 6.1, O 13.1, N 5.7, CO ₂ 9.0.

10 parts of the dyestuff prepared according to Example 4, with heating at 80 to 90 ⁰ C in a mixture of 50 parts of diethylene glycol monobutyl ether, oleic acid 18 parts, 15 parts of mineral oil and 17 parts of a rosin dissolved. This mineral oil-containing glycol printing ink is characterized by a low tendency to corrosion and good storage stability and leads to prints with good waterfastness.

Claims (1)

Patent claims: Rhodamine dye of the general formula H ₅ C ₂ N C ₂ H ₅ in which R is a hydrogen atom, a methyl or ethyl group, R _{1 is} a hydrogen atom or an ethyl group, R _{2 is} a hydrogen atom or a methyl group and Χ ^{θ is} an H ₂ BO ₃ ⁰ -, HCO ₃ "- or H ₂ PQ ^ -anion .
2. The dye of the formula