US2359462A - Decalcomania - Google Patents

Description

Oct. 3, 1944. Q mc R 2,359,462

DEGALCOMANIA Filed Sept. 21, 1942 FRIT COMPOSITION OF FRIT COMPOSITION OF LOWER9 FUSION POINT HIGHER FUSION POINT s L I PAPER BACKING FIG. I

FRIT COMPOSITION OF .F'RIT COMPOSITION OF LOWER FUSION POINT HIGHER FUSION POINT GUM l4 |3\t |2\L PAPER BACKING TISSUE PAPER FIG. 2

' FRIT COMPOSITIONOF FRITI COMPOSITION OF HIGHER FUSION POINT LOWER FUSION POINT 2s as as NITROCELLULOSE /GUM PAPER BACKING ATTORNEY Patented Oct. 3, 1944 UNITED STATES IPATE NT OFFICE DECALCOMANIA Burton 0. Bricker, Hallway, N. J., assignor to E. r.

du Pont de Nemours & Company,

Wilmington,

Del a corporation of Delaware Application September 21, 1942, Serial No. 459,013 2 Claims. (6141-33) of paper upon which the design is printed in one or more vitrifiable enamel colors. After the design has been printed on the backing sheet, it is transferred to the ceramic surface on which it is finally to app ar, and is afllxed thereto by means of a temporary binder in the position it is desired that is shall occupy. The ceramic article is then subjected to a firing operation which not only destroys the organic material present both in the ink or other vehicle used to bind the color on the paper as well as the bond which fastens it to the ware, but at the same time brings the vitiifiable enamel color compositions to their funent bond with the ceramic surface.

Decalcomanias intended for application to ceramic objects, such as glass ware or chinaware articles, have generally been of two general types. In one pe, the paper backing sheet carries a thin layer of a water soluble gum and it is upon this gummed surface that the design is imprinted. The paper may be either of a sufiicient weight to handle in a printing op'eratiomor it may be tissue paper, in the latter case the tissue being itself fastened to a heavier paper backing sheet by means of a second gummed layer. This latter modification of the first general type of decalcomania transfer is known in the industry as Duplex paper.

The second 'general type of decalcomania transfer is the so-called collodion or slip type. This consists of a'ba'cking sheet, a gummed coating on the backing sheet, and on top of the gum a thin film of nitrocellulose or other water insoluble film-forming material. With type of transfer the design is'printed on the nitrocellulose film surface. v

Both single color designs and multi-color designs may be printed on either of these types of paper by lithography, letter press, intaglio or stencil printing according to the efiect and specific characteristics desired. After completion of the printing operation there is produced a decalcomania sheet wherein the surface of the paper carries a hardened ink layer in which the sion points so that they melt and form a permaparticles of the vitrifiable enamel color compositions are bonded and held in position by means of the organic vehicle.

In applying the design to the ceramic ware or glass article to be decorated, in the case of the Duplex paper, there is first applied a tacky varnish size to the surface of the article and the decalcomania is afiixed to this size layer. The

backing paper is then ordinarily removed with water. When using decalcomania transfers of .thesecond 'type, those in which the color design is imprinted on the collodion film surface, the design is affixed to ,the ware by immersing the paper in water. This dissolves the gum layer between collodion film and backing sheet, and the collodion film may be slid off onto the article to be decorated with the side which has been next to the backing sheet positioned against the surface of the ware. fOrdinarily enough gum remains on the collodionlayer to provide the necessary bond. I

When preparing decalcomanias of the Duplex type, the design as it is affixed on the were to be decorated is inverted, i. e. the vitrifiable enamel color which was printed last is closest to the surface of the ware. In the case of decalcomanias of the slip type the reverse is true, i. e. the sequence of vitrifiable, enamel colors is the same as it appears on the original print.

My invention is concerned the nature and formulation of the vitrifiable enamel colors which are employed in the manufacture of such vdecalcomanias. The essential or primary object of my invention is to provide an improved decalcomania sheet'which, when the design is transferred from it and fired on the cerainic articles to be decorated, will result in.

freedom from blisters and other defects even when the. firing is carried out rapidly or under other adverse conditions. Still another object of my invention is to provide groups of vitnfiable enamel colors which are especially suitable for and which has heretofore been considered unsolvable by practical means, is the tendency of decalcomania designs to form blisters or cracks during the firing operation. This tendency is comania transfer is made up by imprinting the design in a series of cOlOl'S, different percentages of flux being mixed with each color in order to produce a graded series of fusion temperatures with the color of lowest fusion point being next to the surface of the ceramic ware. Although this procedure was originally suggested i almost a quarter of a century ago, it has not been .found utilizable in practice, since the procedure of mixing flux with the various colors cannot be accomplished without destroying the -useful coloring properties. This means that the design which it is desired to reproduce on the ceramic ware is not faithfully rendered, for =v the color values are changed by the necessity for admixing therewith various amountsof flux in order to secure fusion points for the various .layers in accordance with the scheme previously referred to. Since the primary aim of dec'alcomania transfer methods is to produce a faithful and properly colored reproduction of the artist's design, it is obvious that unsatisfactory color reproduction destroys the principal advantage of this method. 7

I have now found that greatly improved decalcomania transfers can beproduced, transfers having great freedom from blistering and other flring defects, if the decalcomanias are prepared utilizing a' series of vitrifiable colors compounded in different fluxes, each color'being in a different flux composition. The principal cause of the enormous losses resulting from employment of the decalcomania method in industry has been the use of a series of vitrifiable enamel -colors madelup, either influxes which are substantially identical in fusing point, or which are wrongly formulated as to fusion point with respectto each other, i. e. not formulated according .to the position in which the vitrifiable color appears on thedecalcomania print, In

preparing decalcomanias of uniform quality and satisfactory firing characteristics, I have found it essentiaito formulate or select a set of colors in a series of fluxes, and to position them in. sequence during the printing operation so that the colors made up from the respective fluxes constitute a sequence varying about degrees (C.) in fusion points. The most fusible color is that at the bottom of the series of layers yhen 60 the design is in place on the surface of the ware being decorated.

It is obvious that in some designs in which as manyas twelve colors may perhaps be present it is not necessary to be concerned about the relative sequence of certain colors in the design when those colors do not overlap or come over or under another color. The position in .se-

is important only with respect to those colors which appear in layers positioned one on top of the other, as it is in such layers that v blistering invariablycauses' severe difliculty i119,

ing the iiring operation. In considering the relative order of fusibility desired, it is primarily the fusion point of the flux particle itself which is well as vitrifiable enamel composition, in which from 5 to 40% of pigment may be present in addition to the frit or flux. In thisrespect'my improved decalcomania transfers, suitable for use in ceramic decoration, are distinguished from previous efforts to overcome the disadvantages incident to their use in commercial decorating operations. In previous attempts the ratio of flux to pigment was controlled, greater or less amounts of flux being added to the pigmentary composition in order to secure the desired sequence of maturing temperatures. Such practice prevents accurate reproductionof the color values in the design, for the pigmentary shade cannot be accurately controlled. As contrasted with this, in my improved decalcomanias, the maturing temperatures of the flux formulations themselves are suitably determined and arranged in sequence, the pigment which is present in addition to the vitrifiable enamel composition having no appreciable effect on the maturing temperature of the color composition. In this way, it is possible accurately to predetermine the exact hu of the fired enamel thereby accurately reproducing the artist's design in the precise color values desired.

The absolute softening points of the vitrifiable color compositions themselves need not possess fixed values, but they may, for example, cover a range of from about 480 C. for the most fusible color to 680 C.'for the least fusible color. The exact incipient softening points of vitrifiable colors or fluxes can be determined by means which are well known to the ceramic industry. No particular problem, therefore, exists in securing a. set of fluxes which are in .each case compatible with the pigments to be employed, 40 which fluxes have various softening points, and

then arranging these-fluxes in printing sequence,.

tile p Figure 2 represents one of the Duplex I type; while Figure 3 represents one wherein the vitrifiable ceramic color layers are imprinted- 7 upon a nitrocellulose or similar film which serves as the impression receiving layer. 8

the paper backing strip, and I the adhering layer of gum or adhesive. Imprinted on the gum layer 1 are two layers of a vitrifiable color composition, 8 and 9. Since 8 and l overlap, or come into contact with each other atcertain portions of the design, it is necessary that I be prepared from a pigment and frit or flux composition of relatively high fusion point, while Q is-prepared by admixing pigment witha flux of lower fusion point. In use, the backing strip is moistened and applied to the ceramic or glass ware article with the portion bearing the design close up against the surface to be decorated. Those portions of the design formed by meansof color 7 composition I accordingly must the lower fusion points, having fusion points at least 20 C. lower than the fusion point of layer I.

In Figure 2, showing comania, I1 is the 76 summed layer, It the-tissue paper strip, and II Referring specifically to Figure l, 8 designates,

the Duplex type of decalbacking strip, I3 the first the ceramic ware to be decorated, it, is formed from a pigmentary material and ceramic flux -of lower fusion point than the ceramic fiux which, when mixed with a pigment, constitutes portion l'l. Referring now to Figure 3, 2| represents th paper backing, 22 the gum layer and 23 the nitrocellulose film. Imprinted on the nitrocellulose film is a design formed of two layers of vitrifiable color composition designated 25 and 28 respectively. In ,use, as previously stated, the paper backing is slipped off and the summed layer applied close up against the surface of the ceramic ware to be decorated. Accordingly, that portion of the design rendered by vitrifiable color composition 25 is closer to the surface of the ware to be decorated than that portion formed by vitrifiable color composition 26. Layer 2! therefore-comprises a pigment and a vitrifiable flux or frit having a lower melting point than the vitrifiable fiux or frit which, when admixed with pigment, constitutes layer 28. As previously stated, especially where a great many colors are involved in the design, vitrifiable color layers 25 and 20 shoulddiifer in fusion points by at least 20 C.

In preparing decalcomanias in accordance with my invention, it i necessary only to utilize the usual and well-known printing techniques. Any satisfactory method for printing the vitrifiable color compositions on the decalcomanla surface nipportingthesamemaybeadopteditbeing ,ofcourse, that theaetof vitrifiable color compositions employed is arranged in order of maturing temperature as previously specified, in order that a decalcomania product will be secured which has the superior firing properties characteristic of my improved transfers.

It should be understood that various changes and modifications may be made from the embodiments given herein as illustrative of my preferred form, which changes would nevertheless fall withl0 in the scope of my invention. Accordingly, its

scope i to be determined in accordance with prior art and appended claims, bearing in mind that it is my intention to comprehend within the scope of the-invention various slight modifications from is preferred form.

I claim:

1. A ceramic decalcomania for use in applying a a multi-color design in ,vitrifiable enamel colors to the surface of ceramic ware which comprises go a backing member, an impression receiving layer secured to said backing member, and a plurality of successively over-lapp vitrifiable colors constituting the design contained on said impression receiving layer. said colors each comprising a pig- 3; ment and a frit, each color having the desired hue and depth and a fusing temperature higher than the color preceding it in the order in which the colors of the decalcomania will be positioned on the ceramic ware, the hue and depth, and the so fusing temperature, of each color being deter mined by the proportion and composition of the frit contained therein, the composition of the frit of at least some of said colors difiering from the composition of the frlt of another color or colors.

to 2. A ceramic decalcomania' as defined in claim I wherein the-fusing temperatures of the succeedin: colors differ from each other by at least 20' C. BURTON C.

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