US2267787A - Method of forming vitreous decalcomanias - Google Patents

Description

Patented Dec. 30, 1941 METHOD OF FORMING VITREOUS DECALCOMANIAS Marco A. Ciavola, Detroit, Mich.

No Drawing. ApplicatlonJuly 18, 1938, Serial No. 219,836

2 Claims.

The object of my invention is to provide a decalcomania for producing facsimiles of labelsv colors because vitreous ink is composed mainly of pulverized colored glass which does not lend itself to application by a roller. When the screen process of printing has been tried, it has been possible to use only a single color because of the almost impossibility of producing screens for the individual colors which accurately register with each other. As a result, only two processes of vitreous labeling are commercially employed. The first and most preferable comprises applying the ink" directly to the bottle through a screen. Only one color can be used with such a process because a separate screen must be made for each subsequent color, which screens are more dimcult to make and register on a bottle than they are on a fiat piece of transfer paper.

The second process comprises using transfers, but, invariably, such transfers are made in a manner difierent than the applicant's. These transfers have all, to' the applicant's knowledge, been made by the powdering process wherein the transfer paper is coated with lacquer or lithographers varnish and before the varnish dries the powdered glass is dusted onto the sticky varnish to form the ink. So little glass will stick to the varnish that subsequent applications must be made if an opaque label is to be had. These subsequent operations are not only expensive but tend to make the edges of the work blurry. It will be apparent that in labels requiring fine detail it is imperative that each color be ,applied all on one operation to prevent blurring. Even when several coats of the powder have been applied by dusting so little color is present that it is usually necessary to back up the designs with a separate layer of white glass.

In my improved process the color may be applied as thickly as desired, which not only forms better appearing labels but also gives sufficient rigidity to the transfer that it may be removed from the transfer paper and deposited on the bottle without danger of breakage.

Specifically, my invention relates to a new method of making screens whereby a plurality of colors may besuccesslvely applied to the transfer paper, and which screens will all be in accurate registry with each other to thus prevent overlapping of the colors.

My invention further relates to the composition of the transfer coating, my improved composition producing a transfer of greater mechanical strength to thereby be more easily slid off the paper and applied to the bottle, and one which will burn to a better finish than the present type of coating. Only the glass remains after firing so that any binder used must burn to a colorless ash and avoid checking of the glass. My improved composition is believed to produce a better label in this respect than other compositions now being used.

The reason that multi-colored screen work has not been successful is that in making the screens the tissue, as the sensitized material is known, must be exposed, then developed and then stretched over the screen. It has been practi-.

cally impossible to control the expansion and stretch of the tissue in various directions so that the screens do not accurately register. With my improved process accurate registry is assured.

With these and other objects in view, my invention consists in the decalconiania, per se, and the steps comprising my improved process,

I as claimed in my claims and described in my specification.

To carry out my improved process a positive photographic glass plate is made for each color of the label, the plates being made in the conventional manner. Each plate has an area thereon corresponding to one of the colors desired. The glass plates should be of uniform size and the designs located thereon so that final registry of the colors is easily obtained.

After these plates are dried a coating of ru ber solution is flowed over the emulsion side of each plate. This rubber solution consists of a colorless latex which rapidly dries to a very thin film which is hardly discernible to the eye but which is insoluble in water. The water insoluble film is very important in this method.-

A coating of collodion is now flowed over the rubber film and after the collodion film has dried,

against the gelatin side of the tissue. The tissue,

while still wet. is exposed through the plate and is then washed in water at F., at which time the paper is peeled on from the gelatin leaving the gelatincoating adhering to the waxed surface. The soluble portions of the gelatin are now washed away leaving a relatively thick negative film adhering to the positive plate. The plate is now placed in cold water at 55 to 65 F. It may be well to mention that the concentranon of bichromate and the exposure time can be regulated to produce in an insoluble film of any reasonable thickness and one which is much thicker than the maximum desirable thickness of paint required on the transfer. The thickness of this gelatin film is quite important as it controls the thickness of paint on the decalcomania.

While the aforementioned plate is still wet a fine mesh screen is placed over the gelatin side and pressed uniformly against the gelatin. The screen may be eithera fine mesh silk screen as is commonly used in the screen printing process or it may be a wire mesh screen which stands up better with ceramic paint. A screen of 200 threads per inch has proved very satisfactory. The gelatin and screen is now allowed to dry and the screen is pulled away from the positive plate. The bichromate and gelatin adhere to the screen. It will be noted that from the time of exposure until after the screen has dried, the tissue never leaves the glass plate so that itis held in an exact uniform position at all times. The dried screen is thus an exact negative of the photographic positive.

A screen is made for each of the colors to be applied and inasmuch as each of the positive plates is in exact register with each other, it follows that each of the screens must be in exact register. I

In making the decalcomania, transfer paper is placed in a conventional screen printing machine and the first screen is brought down against the paper with the gelatin side of the screen against the paper. The proper color of ceramic paint 'is then squeegeed through the screen onto the paper. The colored paint which forms the back..

, ground of the label is preferably applied first,

then the color of the next importance is applied and finally the remaining color or colors.

After the transfers have been dried they may be handled with ease, the ceramic paint adhering to the paper which prevents the destruction of -even the smallest detail. When it is desired to place the transfer upon the bottle, it is dipped in water for a few minutes until the decoration as a whole starts to slide across the paper. The decoration is then slipped edgewise from the paper onto the work. The bottle with the transfer thereon is then heated to approximately 1100 F. where all the colors of paint fuse at one time as a unit to the bottle.

In order that the bottles may not crack, they are gradually brought up to this temperature and gradually cooled in the conventional manner.

As has been mentioned, labels formed from ceramic paint, even by the dusting process, are brittle because the composition of such paint is principally pulverized glass. In order to prevent cracking of such labels, I have found that by mixing lacquer with the pulverized glass and apply- Among the many advantages arising from the use of my improved decalcomania and method of making same, it may be well to mention that labels or decorations of fine detail and of many colors may be formed with one firing. upon the work, which thereby materially reduces the cost over those processes requiring several firings.

With my improved method of making the screens,

exact register of the colors is possible in form-- ing the transfers; whereas, in the past, it was not commercially possible to produce a series 0 screens which would exactly register.

Still further, by forming the screens with various sensitivities and exposures, it is possible to regulate the depth of the bichromate film in accordance with the amount of color desired.

For example, black ink, having a very good covering power, is not required to be nearly as thick as one of the lighter colored inks. Be-

cause of this a considerable saving is brought about as only the amount of ceramic paint absolutet necessary is used in making the transfer.-

Stil further, by mixing the lacquer with the pulverized glass before applying it to the screen, a decalcomania having a deposit thereon of uniform composition is maintained. Thus, when the I decalcomania is being fired,.the lacquer vaporizes from the whole body of the design so that the design dries uniformly on each bottle without checking. Where the lacquer is applied as a base upon which the powder is dusted, the lacquer must vaporize or burn away through the paint which tends to check the paint. In my improved process the lacquer is uniformly distributed through the paint so that when it dries, the check marks are much reduced and less conspicuous than with .the former process.

.Some changes may bemade in the sequence of y the various operations comprising my improved method without departing from the spirit of my invention and it is my, intention to cover by my claims such changes as may reasonably be included within the scope thereof.

I-claim as my invention:

1. The -method of forming self-supporting decalcomanias containing vitrifiable material capable of being transferred to a vitreous surface Y and fired thereon to produce an opaque design, which comprises, forming directly upon decalcomania paper a film of material including pulverized glass and a binder which is decomposed dur ing firing by squeegeeing a suflicient amount of the material forming said film through at leastone silkscreen stencil onto said transfer paper to form said material into a self-supporting film when removed from said paper and to form said opaque design" when applied to said surface and ing the mixture of lacquer and glass through the screen, a relatively hard durable film of the required thickness is formed on thetransfer paper. It has been suggested that a lacquer layer be provided upon which the pulverized glass "is dusted, but it is believed that the applicants process wherein he mixes lacquer with the pull verized glass is unique in the art. Less pitting of the s :rface results than when the lacquer is applied as a layer.

,fired.

2..The method of forming self-supporting decalcomanias of vitrifiable material capable of being transferred to a vitreous surface and of being fired thereon to produce an opaque design,

which comprises, formingdirectly upon decalcomania paper a film of material including pulverized glass and a lacquer binder by squeegeei'ng the material forming said film through silk screen stencils having lacquer insoluble coatings complementary to areas of colors of saiddesign, and building up a layer of said material on said paper through said screens of'sufilcient thickness to form said material into a self-supporting film when removed from said strip and to form said opaque design when applied to said surface and fired. q

MARCO A. CIAVOLA.