US 3894167 A
Improved decalcomanias suitable for high rate application to substrates and for the decoration of ceramic ware and the like contain a layer having low adhesion to a carrier layer, so that the carrier layer is readily removable after application of the decalcomania to a substrate. The desired low adhesion is achieved by the introduction of wax into the decal layer or by incorporating oil in a preprint lacquer layer between the decal layer and the carrier.
Description (OCR text may contain errors)
United States Patent Kluge et al. July 8, 1975  DECALC M FOR DECORATING 3,043,732 7/1962 Shepherd 156/230 CERAMIC WARE 3,445,309 5/l969 Milliken 156/240 3,480,500 ll/l969 Hotter l56/233  Inventors: Karl-Heinz Kl g M n Alfr 3,616,015 10/1971 Kingston 156/230 Eppich, Zirndorf, both of Germany  Assignee: F. Xavier Leipold, Zirndorf, Primary n rge F- Lesmes Germany ASSIISZGHZ Examiner-James Attorney, Agent, or Firm-Blum Moscovitz Friedman  Filed: Apr. 24, 1972 & Kaplan  App]. No.: 246,964
 ABSTRACT  428/40; 156/230; lmproved decalcomanias suitable for high rate applil56/240' 427/147;.428/348; 428/350* cation to substrates and for the decoration of ceramic 2 428/352 428/484 428/486 ware and the like contain a layer having low adhesion Cl- 1 to a carrier y so h the carrier layer i readily Field of Search movable after pp c 0f the eca a o a 156/230 substrate. The desired low adhesion is achieved by the introduction of wax into the decal layer or by incorpo-  References C'ted rating oil in a preprint lacquer layer between the decal layer and the carrier 2,970,076 1/1961 Porth l56/240 3,007,829 ll/l96l Akkeron 156/230 10 Clam, 3 Drawmg Flgures 6 flDi/ES/V' L/M'GUEB 7-- SCQEE/V PZ/N 7'50 COL 0e PPM 7 w/n/ M/b- 5/ \OF/SETOE FZfiTPW/A G #0055 0564i 1 4/ 161? W/7'A/ Dexnenv C047 7 C010/? Rem r W/m/ W44 PP0Vf M64052 F "05044 pnflee IMPROVED DECAL COMANIA FOR DECORATING CERAMIC WARE BACKGROUND OF THE INVENTION In the decoration of ceramic, porcelain, enamel and glassware, the method of wet decalcomania designs has been widely used. Wet transferable ceramic decalcomania pictures are essentially of the following structure:
On a special paper which is permeable to water and which is coated with dextrin or glue or other adhesive substances, a picture is printed using ceramic pigments. For the printing, a variety of processes may be used, such as, lithoprinting, off-set printing, screen-printing and other methods which are more or less standard. The color print containing the ceramic pigments is, at the present time, in most cases overprinted by the screen-printing with a film lacquer, thereby forming the so-called film-lacquer mask". This film-lacquer mask in the form of a foil on the color print gives to the design the cohesion required for the later transfer step. To effect the transfer, the decalcomania is wetted. Water penetrates the paper from the rear softening the layer of dextrin or other adhesives on the inner surface of the paper. The design is thereby released and the decalcomania is then placed against the article to be decorated. The film mask, of course, is transferred with the ceramic color print to the article with the film mask away from the article itself. The foil picture is then firmly pressed by means of a rubber roller against the substrate to eliminate water from therebetween.
After a period of preliminary drying, the ceramic articles are placed into a decoration furnace. During the earlier stages of the baking process, the organic components of the film mask and the printing medium are burned away. The temperature is then raised sufficiently to cause the vitrifiable pigments to flow and ad here to the substrate.
For the making of picture prints, off-set varnishes on a linseed oil or an artificial resin base are used while for the ceramic color-screen prints, screen-printing oils are used. Components in these oils are acrylic resins, ethyl cellulose, celluloseacetobutyrate, or other known synthetic resins which are compatible with the oil used.
The solutions of which the film masks are formed,
contain material such as acrylic resins, ethyl cellulose,
cellulose acetobutyrate, cellulose nitrate, or other resins of similar types.
Although excellent decorative effects have been achieved by means of the wet decalcomania transfer process, it has not as yet been found possible to automate the process so that considerable labor of relatively high skill is involved. The costs of decalcomania supplied as described above are relatively high.
Another technique for the decoration of ceramic ware and the like is the so-called heat release process which involves the use of a special paper coated on one surface with a uniform wax layer. The preferred printing process for use with the wax paper carrier is screenprinting. Unfortunately, it has been found that screenprinting directly on the wax layer is not feasible. Consequently, it is necessary to coat the wax layer first with a preprint lacquer. This preprint lacquer is necessary so that during the heat-transfer process of applying the decalcomania to the substrate, the color print, also termed the decal layer, will be fully transferred to the article. As in the wet method described above, it is desirable that the decal layer containing the ceramic vitrifiable pigment be overprinted by the screen-printing method with a thermoplastic finishing varnish; this varnish provides the necessary adhesion to the substrate.
In making the transfer by which the finishing varnish holds the decals to the substrate, the heat can be provided either by pre-heating the ceramic article (as when it is decorated before cooling completely on leaving the kiln) or by heating the exterior of the decalcomania. Using either method of heating the assembly, the wax layer located between the paper and the preprint lacquer melts and releases the picture from the paper so that the paper can be removed.
It was hoped that it would be possible to automate the transfer ceramic pictures by the introduction of the wax-paper method. Unfortunately, however, these ex pectations have not been fulfilled for the following reasons:
1. The production of a decalcomania based on a waxpaper carrier has proved to be expensive.
2. The printing of a design on paper coated with wax has proved to be extremely difficult.
3. The mechanical transfer of decals to ceramic articles could not be carried out at a sufficiently high rate.
This last difficulty is due to the fact that the speed of the stroke of the transfer machines for wax-paper pictures is dependent on the time interval which is required in order to melt the wax layer between the design and the paper. Only after melting the wax can the paper be lifted off the design which, in the meantime, has adhered to the ceramic article.
SUMMARY OF THE INVENTION Release of a layer containing vitrifiable pigments in the form of a decoration from a carrier is provided for by incorporating a material in a layer other than the carrier itself which weakens the bond between the pigment-containing layer and whatever carrier is used. In one embodiment, the pigment-containing layer itself has incorporated therein a high molecular weight wax which weakens the bond between said layer and a support layer, whether the support layer is the carrier itself or an intermediate layer. In a second embodiment, a preprint lacquer layer containing oil is interposed between the pigment-containing layer and the carrier. Enough oil is incorporated in the preprint layer so that the bond between the preprint layer and the carrier is weak. The carrier may be a paper having a dextrin or glue layer thereon or even a metal foil.
[t is preferable though not necessary that the pigment-containing layer be coated with a thermo-active layer, i.e., a layer containing a thermo-plastic resin which becomes tacky when heated.
Accordingly, it is an object of the present invention to provide an improved decalcomania which can be applied to a ceramic substrate or the like at high speed.
Another object of the present invention is to provide an improved decalcomania which is suitable for application to ceramic objects and the like with automatic removal of a carrier layer.
A further object of the present invention is to provide an improved decalcomania having a bond-weakening component which facilitates the removal of the pigment-containing layer from the carrier.
Still another object of the present invention is to provide an improved decalcomania for application to ceramic objects and the like wherein the decorative layer can be applied by a variety of printing processes.
Yet another object of the present invention is to provide an improved method for applying a decalcomania to ceramic objects and the like, the method incorporating the possibility of using automatic equipment for removal of a carrier layer.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties. and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:
FIG. 1 is a decalcomania according to the prior art in which the carrier paper is removed by wetting;
FIG. 2 is a decalcomania according to the prior art based on a paper carrier having a wax layer coated thereon;
FIG. 3 is a first embodiment of the present invention in which the pigment-containing layer also contains wax;
FIG. 4 is an embodiment of the present invention similar to that of FIG. 3 but having an added thermoactive layer superimposed on a pigment-containing layer;
FIG. 5 is an embodiment of the present invention in which a paper carrier may be removed either in the wet form or in dry form;
FIG. 6 is an embodiment of the present invention similar to that of FIG. 5 but having an adhesive layer superimposed on a pigment-containing layer;
FIG. 7 is an embodiment having a preprint lacquer containing oil between a support layer and a pigmentcontaining layer; and
FIG. 8 is an embodiment of the present invention in which a preprint lacquer layer is readily removable from the decal paper.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the prior art is shown in FIG. 1 in which the decalcomania illustrated consists of a decalcomania paper I, coated with dextrin or glue, a color print 2, containing vitrifiable pigments and a mask 3 to hold the colors together. The color print may be applied by screen-printing, off-set printing, lithoprinting, or flat printing. The mask is applied as a thin lacquer based on a acrylic resin or ethyl cellulose or cellulose acetobutyrate. etc. In this type of construction, the decalcomania paper must be wetted to release it from the color print and the color print is then slid onto the substrate to be coated with the color print itself making contact with the substrate.
A second construction is shown in FIG. 2. A paper I has a wax coating 4 thereon and the wax coating 4 is covered by a preprint lacquer 5. This preprint 5 coating is necessary because it has been found to be impossible to print effectively on a wax layer. In this case, the
color print 2 is generally applied by screen-printing. Finally, color print 2 is covered by a mask 6 containing a thermo-plastic adhesive which is activatable by heat. This type of decalcomania is applied to the substrate to be decorated with mask 6 making contact with the substrate. The substrate itself may be heated in which case the mask 6 is activated to cause color print 2 to adhere to the substrate. A short time later wax layer 4 softens and decalcomania paper 1 can be removed.
Conversely, the decalcomania can be applied to a substrate and heat applied through the carrier which in this case is a paper. Wax layer 4 melts first, after which mask 6 softens causing the decalcomania to adhere to the substrate.
Although the use of wax-coated paper eliminates the need for wetting the carrier paper 1, and although the process of application of the decalcomania to the substrate and removal of the paper may be automated, the process is not as rapid as is desired.
The embodiment of the present invention in its simplest form is shown in FIG. 3 where a layer of decalcomania paper coated with dextrin has printed thereon by screen-printing a decal layer containing vitrifiable pigment with wax incorporated in the composition. The wax may be a high molecular weight polyethylene or a high molecular weight polyglycol. The method of use of this particular construction is to apply the color print directly to the substrate and then to remove the decalcomania paper. This can be done either by wetting the decalcomania paper or by heating either face of the decalcomania so as to melt the wax. The wax performs a double function in that it decreases the adhesion of the color print to the decalcomania and in that it melts when heat is applied making it possible to remove the decalcomania paper in dry condition. In this type of construction, the color print can be applied by offset or flat printing as well as by screen-printing. The following three examples give compositions suitable for screenprinting. In each of the compositions, enough pigment is incorporated so that the pigment constitutes from one-half to two-thirds of the total weight of the decal layer as deposited.
The dibutylphthalate in each of the compositions (Examples 48 as well as Examples 1-3) functions as a plasticizer. Any other high-boiling solvent compatible with the resin component of the specific composition will also serve as a plasticizer or softener as is well known.
-Continued EXAMPLE 1 Parts by weight Parts by weight polybutylmethacrylate 3 3 polyglycol. molecular weight 1 .000-3 5.000 dibutylphthalate 2 solvent 55 EXAMPLE 4 Parts by weight polyethylene. molecular weight 2000-1000 ll) dibutylphthalate 2 solvent 48 polyvinylacetate. molecular weight EXAMPLE 5 Parts by weight polyethylene, molecular weight 1000-3000 2 dibutylphthalute 2 solvent 54 polyvinyl-acetate. molecular weight EXAMPLE 6 Parts by weight polyethylene. molecular weight 2.000-3.00(J l0 polybutylmethacrylate 40 dibutylphthalate 2 solvent 48 EXAMPLE 7 Parts by weight polybutylmethacrylate 4O polyglycol. molecular weight 1.0U035.U0(J S dibutylphthalate 2 solvent 53 EXAMPLE 8 Parts by weight polyglycol. molecular weight LOGO-35.000 5 dibutylphthalate 2 polyvinylucctntc. molecular weight 1 00.000-2 000.000 40 solvent 53 As would be expected from the relationship of the embodiments of FIGS. 3 and 4, dextrin coated decal paper 8 can be removed either by wetting or by heating in dry condition.
Printing on decalcomania paper is a relatively difficult process. Consequently. it is desirable, as shown in FIG. 5, to interpose a preprint lacquer layer 5 between the carrier paper 1 and color print layer 7 containing wax. This arrangement is improved by further coating color print layer with adhesive layer 6 as shown in FIG. 6. The carrier is shown in both FIGS. 5 and 6 as being a decalcomania paper but it could equally well be a foil such as aluminum foil. In both cases, the carrier is removed from the preprint lacquer layer by means of heat applied to either the substrate to be coated or to the carrier.
As pointed out above, each of the color print layers contains wax so that the bond with the carrier is weak, thereby making it relatively simple to remove the carrier. It is also possible to weaken the bond with the carrier by using a preprint lacquer containing oil. Such a structure is shown in FIG. 7 in which decalcomania paper 1 is coated with preprint lacquer 9. a preprint lacquer of this type can be color printed by screen, offset or flat printing. Preferably, an adhesive lacquer layer 6 is also screen printed on color print layer 7.
A structure which gives particularly good results is that shown in FIG. 8 in which decalcomania paper I is coated with a removable preprint lacquer layer 10, a color print including wax and a finishing varnish 6 also including wax. Again, the decalcomania paper is removed by the application of heat to either face of the structure.
The preprint lacquers 9 and 10 may be prepared with acrylic resins as the base and contain admixed thereto Castor oil, mineral oil or other oils which have the property of causing the lacquer to make only a weak con nection with the dextrin coating of the decalcomania paper. As a result, after drying, the carrier can readily be lifted or blown off the remainder of the decalcomania structure in dry condition.
It is thus seen that the bond between the color print layer containing vitrifiable pigment and the carrier can be weakened either by incorporating wax in the color print layer or by incorporating oil in a preprint layer thereby making it feasible to separate the carrier from the color print layer with sufficient ease and speed so that automation becomes possible and so that the cost of application of decalcomanias is substantially decreased. Also, the process is suitable for use not only glazed ceramic but on unglazed ceramic as well.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the article set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompany drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all ofthe generic and specific features of the invention herein described, and all statemerits of the scope of the invention which, as a matter of language, might be said to fall therebetween.
What is claimed is:
l. A decalcomania suitable for application to a ceramic substrate at high rate consisting essentially of a carrier layer, an overlying decal layer containing vitrifiable pigment and a thermoplastic resin, and an agent for facilitating the separation of said decal layer from said carrier layer, said agent consisting essentially of a member selected from the group consisting of a wax in said decal layer and a preprint lacquer layer between said decal layer and said carrier layer, said preprint lacquer layer containing a quantity of oil effective for facilitating said separation said wax being selected from the group consisting of polyethylene and polyethylene glycol.
2. A decalcomania as defined in claim 1, wherein said thermoplastic resin is polybutylmethacrylate.
3. A decalcomania as defined in claim 1 further comprising a finishing adhesive layer containing a thermoplastic resin overlying said decal layer, thereby causing said decal layer to adhere to a substrate when said decalcomania is applied to said substrate and heated to a temperature high enough to render said finishing adhesive layer tacky.
4. A decalcomania as defined in claim 3, wherein said thermoplastic-containing layer when deposited on said decal layer comprises at least one thermoplastic resin, a plasticizer and at least one solvent.
5. A decalcomania as defined in claim 1, wherein said decal layer when deposited contains a pigment, a thermoplastic resin, a wax selected from the group consisting of high molecular weight polyethylene and high mo- ,lecular weight polyglycol, a plasticizer and a solvent. 6. A decalcomania as defined in claim 5, wherein said pigment constitutes from one-half to two-thirds of said decal layer by weight as deposited.
7. A decalcomania as defined in claim 1, wherein said carrier is a paper permeable to water and is coated with glue or dextrin.
8. A decalcomania as defined in claim 1, wherein said carrier is a metal foil.
9. A decalcomania as defined in claim 1, wherein said preprint lacquer layer contains sufficient oil to weaken any bond between said preprint layer and said carrier, thereby making it possible to strip said carrier from said preprint lacquer layer.
10. A decalcomania suitable for application to a ceramic substrate at high rate consisting essentially of a carrier layer permeable to water and coated with dextrin or glue, an overlying decal layer containing vitrifiable pigment, wax, and a thermoplastic resin, and a finishing layer containing thermoplastic resin overlying said pigment-containing decal layer, said carrier being detachable from said decal layer by wetting said carrier subsequent to attaching said decalcomania to a substrate by heating.