Printable ink mixture, method for producing a colored overprint, and use of the ink mixture

Abstract

A printable ink mixture may include: a medium, orthophosphoric acid, at least one metal oxide, and at least one pigment. A method for producing a color print on a glass or ceramic surface may include: producing an ink mixture including a medium, orthophosphoric acid, at least one metal oxide, and at least one pigment, applying the ink mixture to the glass or ceramic surface, removing the medium from the ink mixture, and baking the ink mixture on the glass or ceramic surface to produce the color print.

Claims

1. A lead-free printable ink mixture consisting of: a medium, orthophosphoric acid, at least one type of metal oxide nanoparticles, wherein the metal oxide nanoparticles comprise a trivalent metal cation selected from the group consisting of: cations of scandium, yttrium, and lanthanoids, and the metal oxide nanoparticles have an average primary particle size of 15-20 nanometers and an average agglomerate size of 30-100 nanometers, and at least one pigment, wherein the medium is present in a proportion of 25 to 45% by weight, the orthophosphoric acid in a proportion of 8 to 22% by weight, the metal oxide nanoparticles in a proportion of 1 to 3% by weight and the pigment in a proportion of 35 to 50% by weight, wherein the medium is anhydrous glycerol, and wherein the at least one pigment is suspended in the orthophosphoric acid.

2. A lead-free printable ink mixture as claimed in claim 1, wherein the orthophosphoric acid comprises water in a concentration of 15%.

3. A lead-free printable ink mixture as claimed in claim 1, wherein the pigment is selected from inorganic C.I. pigments.

4. A lead-free printable ink mixture as claimed in claim 1 that conforms to the EU guideline relating to restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS).

5. The lead-free pintable ink mixture of claim 1, wherein the at least one type of metal oxide and the at least one pigment do not react with the medium and the orthophosphoric acid, wherein the lead-free printable ink mixture has storage stability of at least twelve months.

6. The lead-free printable ink mixture of claim 1, wherein the lead-free printable ink mixture has storage stability of at least twelve months.

7. A process for producing a color print on a glass or ceramic surface, comprising: producing a lead-free printable ink mixture, consisting of: a medium, orthophosphoric acid, at least one type of metal oxide nanoparticles, wherein the metal oxide nanoparticles comprise a trivalent metal cation selected from the group consisting of: cations of scandium, yttrium, and lanthanoids, and the metal oxide nanoparticles have an average primary particle size of 15-20 nanometers and an average agglomerate size of 30-100 nanometers, and at least one pigment, applying the lead-free printable ink mixture to the glass or ceramic surface, removing the medium from the lead-free printable ink mixture, and baking the lead-free printable ink mixture on the glass or ceramic surface to produce the color print, wherein the medium is present in a proportion of 25 to 45% by weight, the orthophosphoric acid in a proportion of 8 to 22% by weight, the metal oxide nanoparticles in a proportion of 1 to 3% by weight and the pigment in a proportion of 35 to 50% by weight, wherein the medium is anhydrous glycerol, and wherein during baking, the orthophosphoric acid is condensed to form at least one of cyclic metaphosphate and catenated polyphosphate.

8. The process as claimed in claim 7, wherein the medium and the orthophosphoric acid are mixed in said producing, and the at least one pigment and the at least one type of metal oxide nanoparticles are dispersed in the mixture.

9. The process as claimed in claim 7, wherein said applying is effected by a method selected from a group comprising flexographic printing, stencil printing and screen printing.

10. The process as claimed in claim 7, wherein said removing is performed at a temperature selected from the range of 250° C. to 350° C., and for a period selected from the range of 5 to 8 seconds.

11. The process as claimed in claim 7, wherein said baking is performed as a temperature selected from the range of 450° C. to 650° C., and for a period selected from the range of 120 to 150 seconds.

12. A glass and/or ceramic surface comprising a lead-free printable ink mixture applied thereto; wherein the lead-free printable ink mixture consists of: a medium, orthophosphoric acid, at least one type of metal oxide nanoparticles, wherein the metal oxide nanoparticles comprise a trivalent metal cation selected from the group consisting of: cations of scandium, yttrium, and lanthanoids, and the metal oxide nanoparticles have an average primary particle size of 15-20 nanometers and an average agglomerate size of 30-100 nanometers, and at least one pigment, wherein the medium is present in a proportion of 25 to 45% by weight, the orthophosphoric acid in a proportion of 8 to 22% by weight, the metal oxide nanoparticles in a proportion of 1 to 3% by weight and the pigment in a proportion of 35 to 50% by weight, and wherein the medium is anhydrous glycerol.

13. The glass and/or ceramic surface as claimed in claim 12, wherein the orthophosphoric acid comprises water in a concentration of 15%.

14. The glass and/or ceramic surface as claimed in claim 12, wherein the at least one pigment is selected from inorganic C.I. pigments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the disclosed embodiments. In the following description, various embodiments described with reference to the following drawings, in which:

(2) FIG. 1 shows a schematic side view of a luminous body with a print

DETAILED DESCRIPTION

(3) The following detailed description refers to the accompanying drawing that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced.

(4) Three working examples for ink mixtures are specified hereinafter. Because of the high variability, especially with regard to the pigments in the ink mixtures, these three working examples should be understood merely as examples for illustration. Any color not mentioned here can be produced as an ink mixture through use of other pigments.

(5) 1. Green Ink Mixture

(6) TABLE-US-00001 Anhydrous glycerol 40.26% by wt. 85% orthophosphoric acid 15.09% by wt. Aluminum oxide Al.sub.2O.sub.3  1.30% by wt. (CO,Ni,Zn) (Ti,Al).sub.2O.sub.4 (C.I. 33.59% by wt. Pigment Green 50) (Ti,Ni,Sb)O.sub.2 (C.I. Pigment  9.76% by wt. Yellow 53)

(7) 2. Blue Ink Mixture

(8) TABLE-US-00002 Anhydrous glycerol 32.86% by wt. 85% orthophosphoric acid 19.80% by wt. Lanthanum oxide La.sub.2O.sub.3  1.82% by wt. CoAl.sub.2O.sub.4 (C.I. Pigment Blue 28) 45.52% by wt.

(9) 3. Black Ink Mixture

(10) TABLE-US-00003 Anhydrous glycerol 29.91% by wt. 85% orthophosphoric acid 20.74% by wt. Yttrium oxide Y.sub.2O.sub.3  1.67% by wt. Cu(Cr,Fe).sub.2O.sub.4 (C.I. Pigment Black 28) 47.68% by wt.

(11) In each of these working examples, the sum of all constituents adds up to 100% by weight. While the color which results in the green ink mixture is produced by a mixture of two pigments, the resulting colors of the blue and black ink mixtures are each produced by one pigment.

(12) The ink mixtures mentioned are produced by mixing the anhydrous glycerol and the 85% orthophosphoric acid in the portions specified above. The respective pigment(s) is/are added to this mixture and incorporated by means of a dispersing machine. Finally, the particular metal oxide is added in nanopowder form and likewise dispersed. Thus, a viscous suspension is produced, which has good storability, since the metal oxides and pigments do not dissolve in the glycerol/orthophosphoric acid mixture. The presence of nanopowder additionally prevents the sedimentation of the pigments in the ink mixture. The nanopowder thus acts as a kind of spacer in the ink mixture.

(13) According to the above details, the ink mixtures can be applied to glass or ceramic surfaces by a process for producing a color print, and are processed to give an abrasion-resistant, stable color print having good adhesion to the glass or ceramic surface.

(14) As can be inferred from the working examples, the ink mixtures are simple lead-free compositions which are nontoxic and have high variability, since the selection of colors from the inorganic C.I. pigments is so great that any desired color can be produced. In addition, the ink mixtures, because of their composition, have particularly good storability.

(15) FIG. 1 shows the detail of a schematic side view of a luminous body 10 with a print 2. Part of a tube 1 with a glass surface is shown, to which a print 2 has been applied. Also shown are the casing 4 and the connections 3. This luminous body is, by way of example, a strip lamp. Any other form of luminous bodies not shown here can likewise be provided with a print 2.

(16) The color of the print 2 is, by way of example, black in this figure, but it may include any desired color according to the ink mixture from which the print 2 is produced. The print 2 in FIG. 1 shows the letter “X” repeated several times and in various sizes, which should be understood as an illustration. If the ink mixture, for example, is applied to the glass surface by means of flexographic printing and then baked thereon for production of the print, it is possible to show any desired sequence of characters. For example, the print may show manufacturer markings or trademarks.

(17) While the disclosed embodiments has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosed embodiments as defined by the appended claims. The scope of the disclosed embodiments is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.