US2476570A - Decoration of ceramic ware - Google Patents

Description

Patented July 19, 1949 2,476,570 DECORATION F CERAMIC wane Harry T. Van Horn, Highland Park, N. J., and Robert M. Koppenhoefer, Jackson Heights, N. Y., assignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application January 24, 1947,

Serial No. 724,238

This application has to do with methods for the decoration of ceramic ware and particularly with those methods of decoration wherein a pattern or design is placed upon the ware by means of decalcomania or similar transfer methods.

The wares so deooratedare usually designated by the general term white ware and may be vitreous or semi-vitreous having absorption factors running from practically 0 absorption up through 445% absorption and sometimes higher generally found in semi-vitreous bodies, Such '7 Claims. (0]. 154-99) 1 painted over the colors which holds colors on white ware may be decorated either under-glaze or over-glaze. The colors which comprise design indicia, trademark identification or other marking or decoration, maybe applied by painting, stencilling, stamping or transfer printing such as the use of decalcomania. This invention is particularly concerned with the latter.

Transfer printing is the most common of any of the methods of decoration. In this method the colors are prepared with oil and then smeared over an engraved plate or roll. This plate contains the desired design or the part of it that is all one color. The engraving is then mounted on a printing press and when an impression is made on paper the design is printed on the paper with the coloring oxides. If several colors are to be included in the design they may each be printed in turn on the same paper. After the printing is complete the paper is dried and the designs printed on it cut into individual pieces. The color is transferred to the ware by applying an adhesive coating to the ware or to the decalcomania and then placing the printed sheet face downward in the proper position. The paper and colors adhere to the ware but the paper may be softened and removed by soaking it in water without disturbing the colors. The ware is then placed in a hardening oven which burns the organic matter and oils from the ware and.

color.

In case the transfer printing has been done with under-glaze colors, the ware after hardening is then glazed and given its final firing. In the case where the over-glaze method of application is used, a similar treatment is followed ending with firing which fuses the decoration into the glaze. The present invention applies to both under-glaze and over-glaze transfer printing but is particularly concerned with -under-glaze methods for decoration of materials such as semivitr'eous porcelain dinnerware and will be explained in connection therewith although it is to be understood that the invention is not limited thereto.

Semi-vitreous porcelain dinnerware to be decorated under-glaze usually has a porosity of about 7%. It is decorated by using transfer prints or decalcomania which are made especially for this type of ware and have a layer of flux the were after the primary or application adhesive has been burned off in accordance with the present method of application.

The present method of applying the decalcomania is as follows. A water solution of tapioca is painted on the-ware in order to fill the pores and give them an even surface. A layer of varnish is applied over this and allowed to dry to a tacky condition. The decal is then placed on the varnish and rubbed down well by means of a brush. The'paper backing of the decal is removed by soaking in water. The ware is given a harden on fire (1000 F. to 1500" F.) to remove the organic material whichwould otherwise prevent the glaze from adhering to the ware. The ware is then glazed and refired.

In the present method several dimculties frequently arise. Probably the most serious of these difficulties is one which is inherent in the nature of the primary or application adhesive and method of pre-treatment. It will be noted that after the transfer of colors and removal of paper, the ware is given a hardening firing, the principal purpose of which is to remove the organic material present in the surface conditioner and the application adhesive. When the application adhesive is varnish, the heat treatment of the ware apparently results in a toughening of the varnish film sometime prior to the temperature at which the tapioca filler starts to carbonize. The escape of the gases from this carbonization and probably also the escape of the gases from the carbonization of the varnish itself, frequently causes a curling or flaking of the varnish layer which lifts the metallic oxides of the design colors away from the surface of the ware. As a result they are fused onto the ware out of position and the net result is an imperfect pattern or design.

This invention has for its object the provision of a method of applying suchdecalcomania to ceramic ware whereby the diificulties inherent in the use of the present method are obviated and more. perfect transfer printing may be obtained.

In addition to this primary object, it has several other objects and advantages which are in part obvious and which in part may appear hereinafter.

a to such an extent that they will not interfere with the adherence of an after-applied glaze.

Per Cent by Weight Ingredient Microcrystalline Wax. i

The microcrystalline wax referred to above is a wax of petroleum origin, derived from petrolatum, known variously in commerce as petrolatum wax, amorphous wax, or'microcrystalline wax. These waxes differ from paraffin wax both in nature and point of origin from petroleum and are characterized by very small crystalline size, and usually appear on the market as solids of about 155 F. or higher melting point, with physical appearance somewhat resembling beeswax or ozokerite. The polypropylene is a polymerized olefine product, derived from propylene, having a viscosity of about 3000 seconds Saybolt at 210 F. and a molecular weight of about 2900. Ester gum is the customary article so designated in commerce. Polybutylene is a polymerized olefine, derived from isobutylenes, having a viscosity of about 3000 seconds Saybolt at 210 F. and a molecular weight of about 1280. Hydrofol fatty acids are the commercially available fatty acids derived from hydrogenated fish oils.

It may be seen that these various formulae provide a wax component, a tackiness component, (polypropylene, ester gum, or polybutylene), and emulsifiers.

The compounds set forth above are fiuid water borne emulsions and may readily be applied as a paint, or by dipping, if desired. The emulsion when permitted to dry, not only fills the adjacent pores of the ceramic body thus fulfilling the function of the previously applied tapioca but it also gives a tacky surface which remains tacky for a considerable length of time. This gives rise to several extremely important advantages.

One of these advantages is that the time lapse between the application of the adhesive and the application of the decalcomania is not critical. At present the decalcomania must be applied when the varnish is of the right tack, whereas the adhesiveness of the film deposited from the emulsion does not change greatly with time and scheduling of operations may therefore be attained with greater ease. A second advantage flowing from this continued substantial uniformity of tackiness of the emulsion deposited film is that the decalcomania is easier to apply and rub out and in case of errors in positioning it may readily be removed and're-applied. Since the emulsion replaces both the filler and the adhesive. one of two former processing steps in application is eliminated. However these advantages are of considerably less importance than those arising in subsequent operations because of' the nature of the application adhesive used. When the emulsion adhesive is utilized, the failure of the application by distortion or marring of the design through curling or cracking during the step of hardening firing is completely'absent.

Ingredients of the new adhesive are volatile at comparatively low temperatures and do not harden prior to burning off into a tough film such as is the case with varnish.

As a matter of fact, their elimination by complete volatilization is not necessary and from this arises a second major advantage from the use of this novel adhesive. It will be remembered from the description of the present method, that the removal of the organic material is usually accomplished by a harden on fire in which the ware is subjected to temperatures ranging from 1000 F. to 1500 F. With the novel adhesive herein set forth firing to this extent has been found to be completely unnecessary. In-

stead, the were can be mildly heated to temperatures of the order of 200 F. or somewhat above, whereupon the adhesive material is apparently absorbedinto the interior of the ware in such fashion that it has been found not to interfere with the subsequent application of glaze. Even where transfer printing has been done as an overglaze job, the materials in the present adhesive are largely volatile at temperatures well below those formerly utilized in the subsequent firing. The process is thus seen to consist of the following essential steps:

(1) The application of a hydrocarbon emulsion capable of drying to a tacky film,

(2) The application of the transfer print or decalcomania in the usual manner and (3) The subjection of the ware to higher heating at temperatures less than 1000 F. to remove adhesive, all of which may be followed by appropriate glazing in the manner usual in the art.

The adhesive which is preferred is an adhesive of the general type shown above. In other words, an emulsion the solid material of which consists of about 30 %-40% by weight of the entire emulsion and which solid portion comprises a microcrystalline wax of about 155 F. melting point and a polyisobutylene or polypropylene having a viscosity of about 3000 S. U. at 210 F. In more general terms the emulsion is one containing a wax and a tackiness material. In place of the microcrystalline wax shown above, there may be used any of the more usual waxy materials such as paraflin'waxes, those petrolatums and scale waxes which represent intermediate stages in the manufacture of paraffin wax or microcrystalline waxes, vegetable waxes, synthetic waxes or hard animal or synthetic fats. The tackiness material may be any of those materials which are known to render a wax composition tacky, that is, such materials as the polymerized hydrocarbons, i. e., polyisobutylenes, polypropylenes, polyethylenes, and the like and the various resin materials such as rosins, modified rosins, ester gum, coumarone-indene resins and the like. The emulsifier may be any of the emulsifying materials normally used for the preparation of emulsions of this general class such as for example, various proprietary emulsifying materials, such as the conventional fatty acids, soaps, gums, gelatins, caseins, amines, sulfonates and the like.

The compounding of the emulsion depends to a great extent upon the nature of the ingredients used. It should be, however, an emulsion of relatively high solids content to permit of rapid drying,. although fluid enough for ease in handling. In general a solids content upwards of v twenty percent by weight, preferably around thirty percent by weight, is indicated. Of course, this solids content will influence the choice and amount of emulsifier in a manner well known to those skilled in compounding emulsified materials.

As to the hydrocarbon content of the emulsion, some of the high viscosity polymeric hydrocarbon materials are suitable for emulsion alone, and may be so used, as may selected asphaltic materials which are fluids of high viscosity at application temperatures. In general preference is had for natural and synthetic resinous materials such as poly olefines like the polypropylenes, polybutylenes, and other materials such as ester gum. Many of these, as is known in the art, need a plasticizer or extender, and for this purpose the waxes are found most suitable. The wax component exercises another useful function, namely that of filling or sizing? a porous ceramic bodysupport for the application of decorative indicia thereto.

We have found the most suitable compositions to be those composed of microcrystalline petroleum waxes of around 155 F. melting point and above, together with polymerized olefine products as discussed. We prefer an emulsion of around 30% by weight solids content, with the solids comprising wax and a tackiness agent in proportions ranging from about equal to about three parts wax to one part of the tackincss agent.

We claim:

v 1. Method of applying decoration, indicia, and the like to ceramic ware by means of decalcomania transfers comprising the following steps: applying to the surface of the ware a waterborne emulsion, the solid content of which comprises a tacky adhesive hydrocarbon material and a wax, drying said emulsion to form an adhesive film, applying a decalcomania to said surface by means of said film, removing the backing material from said decalcomania, heating the ware to amoderate temperature sufi'icient to dissipate said film forming material, and finish firing said ware so decorated.

' 2. Method of applying decoration, indicia, and the like to ceramic ware by means of decalcomania transfers comprising the following steps: applying to the surface of the ware a waterborne emulsion, the solid content of which comprises a wax of petroleum origin and a viscous hydrocarbon material present in sufficient amount to render a dry film of said solids tacky and adhesive, drying said emulsion to form an adhesive film, applying a decalcomania to said surface by means of said film, removing the backing material from said decalcomania,

heating the ware to a moderate temperature sufiicient to dissipate said film forming material, and finish firing said ware so decorated.

mania transfers comprising the following steps:

, material, and finish firing said ware so decorated.

3.. Method of applying decoration, indicia, and

the like to ceramic ware by means of decalcomania transfers comprising the following steps: pp y n to the surface of the ware a waterborne emulsion, the solid content of which conprises a wax of petroleum origin and a. viscous polymerized hydrocarbon material present in sufiicient amount to render a dry film of said solids tacky and adhesive, drying said emulsion to form an adhesive film, applying a decalco-- mania to said surface by means of said film, removing the backing material from said decalcomania. heating the ware to a moderate temperature sumcient to dissipate said film forming material, and finish firing said ware so decorated.

4, Method of applying decoration, indicia, and the like to ceramic ware by means of decalco- 5. Method of applying decoration, indicia, and the like to-ceramic ware by means of decalcomania transfers comprising the following steps: applying to the surface of the ware a water borne emulsion, the solids content of whichis of at least about 20% by weight, the solids consisting of a wax and in admixture with said wax a viscous hydrocarbon material in amount sufiicient to render the dried solid film tacky and adhesive, drying said emulsion to form an adhesive film, removing the backing material from said decalcomania, heating the ware to a moderate temperature suflicient to dissipate said film forming material, and finish firing said ware so decorated.

6. Method of applying decoration, indicia, and the like to ceramic ware by means of decalcomania transfers comprising the following steps: applying to the surface of the ware a water borne emulsion, the solids content of which is of at least about 20% by weight, the solids consisting of a wax of petroleum origin and in admixture with said wax a viscoushydrocarbon material to the extent of at least about one-third of the Weight of the wax present and sufficient to render the dried solid film tacky and adhesive, drying said emulsion to form an adhesive film, removing the backing material from said decalcomania, heating the ware to a moderate temperature sufficient to dissipate said film'forming material,

and finish firing said ware so decorated.

7. Method of applying decoration, indicia, and the like to ceramic ware by means of decalcomania transfers comprising the following steps: applying to the surface of the ware a water borne emulsion, the solids content-of which is of at least about 20% by weight, the solids consisting of microcrystalline petroleum wax and in admixture with said wax a viscous hydrocarbon material to the extent of at least about one-third of the weight of the wax present and sufi'icient torender the dried solid film tacky and adhesive, drying said emulsion to form an adhesive film, removing the backingmaterial from said decalcomania, heating the ware to a moderate temperature sufiicient to dissipate said film forming material, and finish firing said ware so decorated.

HARRY T. VAN HORN. ROBERT M. KOPPENHOEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,238,018 Earhardt Apr. 8, 1941 2,290,393 Thomas July 21, 1942 2,324,433 Scheetz July 13, 1943 2,404,519 Morrison "July 23, 1948