US2128588A - Decalcomania paper - Google Patents

Description

Patented Aug. 30, 1938 v UNITED STATES DECALCOMANIA PAPER John MacLanrin, Ware, Mall.

No Drawing. Application December 11, 1935,

Serial No...53,956

1 Claims. 41-43) This invention relates to decalcomania papers and the manufacture and use of these products. A decalcomania papenas customarily made, consists of a water leaf, 1. -e., unsized, backing 5 sheet (or a sheet that can be made to function in the same manner and therefore is the equivalent of a water leaf sheet) with one or more watersoluble adhesive coatings applied, one over the other, to one surface of said sheet. The decalcomania design is printed on the adhesive surface, a number of printing operations being required to build up the decalcomania print. In applying the decalcomania print to the article to which it is to be afiixed, the entire decalcomania assembly is dipped in water which penetrates through the backing sheet and softens the adhesive coating sufliciently to permit the easy separation or "release of the print from the backing sheet.

The production of a satisfactory decalcomania paper requires both the use of the proper materials, and also a very accurate control of the application and assembly of those materials. Not only must the backing sheet be so made as to allow a quick release of the print when water is applied, but the coatings must be applied in such a manner that this property will not be substantially impaired. It is highly important that the coatings be applied evenly, that the final surface be level and smooth, and that the entire sheet be of a. uniform thickness. If the adhesive coating is not applied evenly, excessive buckling and wrinkling of the sheet will be produced during drying.

These requirements demand the exercise of great care and constant attention in the coatin and calendering operations. Again, the length of time required for the release of the prints is amatter of great practical importance, for the prints often consist of revenue stamps, bottle labels, and the like, which must be applied in great numbers, and the length of time required for the application of the print enters largely into the matter of cost. Thus it is important to reduce the length of time required for the release as much as possible, and it is commonly stipulated in the purchase of such papers that the release must be accomplished within a definite period of time, say twenty seconds.

The present invention is especially concerned 50 with the foregoing requirements. It aims to improve decalcomania papers with a view to providing a superior product and facilitating both the manufacture of such papers and the application of the decalcomanias printed thereon.

In decalcomania paper as heretofore made both the backing sheet and the adhesive coatings have been white, or substantially colorless.

I have found that by coloring the paper comprising the backing sheet, preferably with dyes, I can facilitate both the accurate control during the manufacturing operation of the spreading of the adhesive coatings to insure that they be applied evenlyand uniformly, and also the operation of releasing the print from the paper backing, decreasing the time required for this step.

In the manufacturing operation it is customary for the operator in charge of the application of the adhesive coating materials to the sheet to keep constant watch of the paper discharged from the coating machine with a view to detecting any non-uniformity in the coating. I have found that when colored paper is used as the backing, irregularities in the adhesive coating applied to the sheet are detectable by resulting variations in the depth, tone or shade of the color of the sheet in a manner impossible if white or colorless paper is used, these variations in tone or shade being due to difierences in the degree of wetting to which the paper is subjected by the coating, which ,is applied in the form of an aqueous solution. Accordingly, when the coating material is applied to colored paper, if irregularities in the coating occur, the operator can instantly note them and take the necessary steps to overcome them by readjustment of the feeding mechanism, or otherw se.

The use of a colored backing sheet is of further advantage in facilitating the control of the calendering operations which follow the coating step or steps. Here variations in the pressure applied to a colored sheet produce changes in the shade of color, an increase in pressure tending to darken or deepen the shade. Such changes in shade are observable by the operator, and enable him to make such changes in' theadjustment of the pressure on the calender stack as may be necessary to correct the difliculty. No such changes are produced on a white sheet except in those instances when the pressures used are so excessive as to blacken or darken the white paper.

The foregoing advantages are of value in enabling the manufacturer to produce a more even and uniform decalcomania paper. Moreover, the operation of releasing the print from the backing sheet is facilitated by the use of a colored backing sheet in accordance with my invention. The use of a colored backing sheet makes it easier for the operator to determine correctly when the penetration of water has been complete enough and uniform enough to make the releasing operation safe, since the degree of penetration of water through the colored sheet reflects itself by changes in the shade of the color.

.In addition, I have found that the presence of dye in the sheet increases its capillarity or absorptive properties, so that the water applied to .the sheet in order to effect the release of the print penetrates the sheet more rapidly than when there is no dye in the sheet. Tests have shown that-the time required for penetration of water sufficient to release the print in the case of a backing paper containing enough dyestuil' to give it a distinctive color is less by as much as 15% than that required for the penetration necessary to release the print in the case of an uncolored sheet. This advantage in the releasing operation, when a colored sheet is used in accordance with my invention, materially reduces the time required for the operation, and, therefore, substantially reduces its cost.

I prefer to use direct dyes as distinguished from basic or acid dyes. These are more convenient to use because of the fact that they are absorbed readily by the unsized fiber of the paper and do not require the use of mordants or setting agents. In general they appear to produce more satisfactory results and to effect more pronounced improvements in the capillarity of the sheet.

Another advantage of practical value arises from the use of dyes in the paper stock in the manufacture of decalcomania paper when such paper is used in the manufacture of revenue and tax stamps, liquor labels, proprietors stamps, and

other products of a similar nature which are customarily applied to cigarettes, tobacco, liquors and various other commodities. Counterfeiting of such stamps and labels presents a serious problem. When paper containing dyestuffs is used as the backing material, the detection of counterfeiting is made easier, for each individual dye has its own characteristic reactions with certain reagents, these reagents reacting with the dyestuffs to produce characteristic color changes. For example, an agreeable green color can be given to the fiber by dyeing it with a direct dye known in the trade as Pontamine Green G X (du Pont)-Erie Green G Y (National). An application of concentrated nitric acid changes the color to a deep purple which gradually fades to a. rose. Dilute nitric acid produces a red color, gradually changing to a lighter shade. Other characteristic changes in color occur upon treatment with other reagents. Similarly, a paper in which the fiber is colored with the direct dye known as General Dyestufl Blue Bra-concentrated will, when treated with concentrated nitric acid, turn a greenish shadb, changing rapidly to yellow, and subsequently to an orange. Or, if treated with concentrated sulphuric acid, it will change to a light green which, in turn, will change slowly to an orange. As inspector or detective, informed as to the dyestuff used in manufacturing the genuine product and provided with a reagent, the effect of which upon that dyestufl is known, can detect counterfeits by applying the reagent to them, unless it happens that the counterfeiter, in manufacturing the counterfeit paper, has used the same dyestufl or combination of dyestuffs used in the genuine paper to produce 'the same color. This is un likely because of the great number of dyes that can be used to produce the same color. Y

In addition to coloring the paper base, I prefer to color also the adhesive coating used in my paper, preferably by incorporating therein dye-- stuffs similar to those used in the paper base. The adhesives heretofore used have been colorless or transparent. Coloring the adhesive aids the machine operator in detecting irregularities in the amount of coating applied, as also in the pressure applied by the calenders through resulting changes in the shades or tone of the color. It also facilitates the detection of counterfeits in cases where the prints are usedfor stamps or labels, etc., since enough of the adhesive adheres to the print. when removed from the paper and applied to an article so that its presence can be seen and it can be tested with a suitable reagent. Thus material advantages may be gained by coloring the adhesive coating even without coloring the paper base.

It will be understood that the same advantages can also be obtained in the manufacture of special decalcomania papers which involve the application of additional coating materials to the adhesive coating applied to the backing sheet. For example, a coating of lacquer is sometimes applied on top of the final adhesive coat, and the printing is done on this lacquer film.

Having thus described my invention, what I desire to claim as new is:-

1. A decalcomania paper comprising a waterleaf backing sheet containing dyestuif of the direct class in sufficient quantity to impart a distinctive color to the sheet, and a coating of adhesive thereon adapted to take decalcomania printing.

2. A decalcomania paper comprising a waterleaf backing sheet and a water-soluble coating thereon adapted to take decalcomania printing, said backing sheet containing a dye of the direct class serving to give said sheet a distinctive color and having the characteristic of increasing the capillarity of the sheet.

3. A decalcomania paper having as a backing layer a sheet of water leaf paper containing dye in suflicient quantity to impart a distinctive color to the paper, and a layer of adhesive coating thereon adapted to receive decalcomania printing, said colored backing layer being adapted to change color on the application of a suitable reagent.

4. A decalcomania paper having as a backing layer a sheet of water-leaf paper containing dye in sufiicient quantity to impart a distinctive 001- or to the paper, and a layer of adhesive coating thereon adapted to receive decalcomania printing, said dye being adapted to change color upon the application of a suitable re-agent to said backing layer. 7

5. A decalcomania paper having as a backing layer a sheet of water-leaf paper containing direct dye in sufficient quantity to impart a distinctive color to the paper, and a layer of adhesive coating thereon adapted to receive decalcomania printing, said colored backing layer being adapted to change color on the application of a suitable re-agent.

6. A decalcomania paper having as a backing layer a sheet of water-leaf paper containing dye in sufficient quantity to impart a distinctive color to the paper, and a layer of adhesive coating thereon adapted to receive decalcomania printing, said colored backing layer being adapted to change color on the application of a suitable re-agent, said adhesive coating being adapted to change color upon the application. of a suitable re-agent.

7. A decalcomania paper having as a backing layer a sheet of water-leaf paper containing dye in suflicient quantity to impart a distinctive color to the paper, and a layer of adhesive coating thereon adaptedto receive decalcomania printing, said colored backing layer being adapted to change color on the application of a suitable reagent, said adhesive coating containing an identifying dye also adapted to change color upon the application of a suitable reagent.

JOHN MACLAURIN.