US2425653A - Decalcomania paper - Google Patents

Description

Patented-Aug. 12; 1947 The Cuneo Press, Inc.,

lanai Illinois John W. Stewart, m. Forest, m., ama to Chicago, 111., a corpora- No Drawing ml! 24, 1945,

flcrlalNo. 595,655

,This invention relates to decalcomania paper on which designs are printed in such a manner as to be transferrable to another surface.

It is common practice to prepare paper for this purpose by applying a suitable water soluble coating to the surface "of an unsized backing sheet of paper. The decalcomania design or other printed matter is then printed on the coating or otherwise applied theretoxas, for example. by a stencilin process. An unsized or so-called "water leaf paper has always been used for the backing sheet to facilitate the penetration of the sheet by the water used for the purpose of releasing it from the decalcomania design at the desired stage in the process of applying the design to an article such as a piece of furniture to be deco,- ra'ted. or a'plate-glass window on which the dcsign is to serve as a sign.

A backing sheet of this character is readily affected by changes in atmospheric humidity. This causes the sheet to curl after the design has been applied to one surface; or. in the printing process, if several printings are-required to complete the design, the swelling or shrinking of the paper may interfere seriously with accurate registration of the several impressions. This is especially true in the case of silk screen and multi-color work.

It is an object of the present invention to provide a decalcomania paper which shall not be subject to any substantial variation in dimensions as a result of variations of atmospheric humidity, and which will not tend to curl after application of the decalcomania design thereto.

It is also an objectof the invention to provide a simple method of procedure for so preparing paper to be used for decalcomania.

More specifically, it is an object of the inven- I tion to provide a decalcomania paper composed of a water absorbent backing sheet treated on one surface with a coating adapted to take adecalcon'iania design but releasably bonded to the sheet by a water the opposite face with a water releasable coating which operates to balance stresses in the paper and. to protect it from the effect of changes in atmospheric humidity.

Other objects and advantages of, the invention will appear from the following description.

For the purpose of this invention a decalcomania paper is composed, as'heretofore, of a water absorbent or so-called (water leaf" backing sheet which may be treated on one surface in accordance with any usual procedure so that printed matter or other design material may be soluble adhesive and treated on,

. f 2 applied to that surface, but will be released upon the application of sumcient water to the backing sheet iscoated with a gelatinous layer which is applied as a liquid preparation which, when dry, adherent to the paper. This dry gelatin film tends to exclude atmospheric moisture from the paper itself and to seal into the paper moisture already present.

The gelatinous coating material for the practice of this invention is prepared by swelling granular, gelatin in from four to ten times its own volume of a solution composed of water. and methyl alcohol. The gelatin is held in suspension or in colloidal solution, and to expedite this result the mixture should be warmed to approximately 115 F. The proportion of methyl alcohol to water employed in the preparation of the liquid vehicle will depend upon the rate of evaporation desired. A preparation containing forty percent methyl alcohol and sixtypercent water '25 has been found quite satisfactory.

The liquid preparation of gelatin thus produced may be applied to the'surface of the paper in any convenient manner. If individual sheets are treated they may be coated by the use of a brush; but a more efilcient method will be to add this coating in conjunction with the operation by which the opposite surface of the paper is coated with the usual sizing and adhesive to receive the decalcomania design. Ordinarily. this will be done as the paper is wound from a roll, with the web traveling over a coating roller which is dipped in a bath of the coating material and provided with the usual doctor bar or roll to control the thickness of the film applied. This method is suitable for application of the gelatin coating,

. provided the bath is maintained at a temperature of approximately F.

fiince in a decalcomania sheet, the surface which is to receive the design is covered with a water releasable coating, usually containing starch and dextrose, the coating applied to the other side of the sheet must not permeate the fibers of the paper-otherwise, the decalcomania gelatinous coating herein described lends itself to either method. It can be sponged away, because, upon the addition of an excess of water, the gelatin swells and releases its hold on the paper; or, if the flotation process is employed, the immersion of the gelatin film in water produces the same result, and it is readily removed. The quantity of gelatin employed is very small in proportion to the area of the paper covered thereby so that the amount taken into a water bath used in the transfer process is not appreciable and has no undesirable eilect on the ingredients of the other coating and does not interiere in any way with the usual procedure.

While there is described herein a specific material, and while the description suggests a particular method of preparing and applying this material, it is to be understood that the invention is not limited either to the materials mentioned or to the method disclosed, but is intended to embrace all equivalents and'modifications thereof which may fall within the scope of the ap- I pended claims. In fact, the invention is not limited to the use of methyl alcohol, which evaporates at about 64.7 C. Ethyralcohol has a boiling point of 78.4 C., acetone boils at 565 0., and a tertiary butyl alcohol boils at 82.9 C. Any of these 4 reagents is entirely miscible with water, and in view oi its low boiling point will serve satisfactorily in place of methyl alcohol in preparing the coating of gelatin as above described. Methyl alcohol, however, is preferable for large-scale pro- I duction.

I claim as my invention The method of preparing non-curling decalcomania paper, which consists in releasably bonding,.to one side of a backing sheet of water absorbent paper, by a water-soluble starch-dextrose adhesive, a coating adapted to take a decalcomania design, and covering the opposite side of the sheet with a dried layer of granular gelatine which has been swelled in a warm mixture oi water and alcohol in a ratio of generally three to two.

. JOHN W. STEWART.

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

UNITED STATES PATENTS Number Name Date 378,419 Baynes Feb. 28, 1888 778,740 Chelius Dec. 27,1904

1,634,710 Crowell July 5, 1927 2,007,404 I MacLaurin July 9, 1935 2,094,886 Hart Oct. 5, 1937 2,316,120 MacLaurin Aprl 6, 1943 1,909,719 Price May 16, 1933 FEDREIGN PATENTS .Number Country Date 415,256 Great Britain Aug. 23, 1934