US 2920009 A
Description (OCR text may contain errors)
Jan. 5, 1960 F. w. HUMPHNER ,009.
DECALCOMANIA AND METHOD OF USING SAME Filed March 25, 1955 SIZED PAPER S/ZED PAPER -('-POLVETHYLENE L P-RECE/V/NG SURFACE INK IMPRINT -HEATED IRON SIZED PAPER 4JEPOLVETHVLENE RECEIVING SURFACE //w( IMPRINT F 4 REMOWBLE $1250 PAPER fl 9' I l I I HP0LrrHrLA/ I RECEIVING SURFACE INK IMPRINT RECEIl ING $UR54CE --POLYETH)*LENE INK IMPRINT IN VEN TOR."
2,920,009 Patented Jan. 5, 1960 due DECALCOMANIA AND METHQD OF USENG SAME Ferdinand W. Humphner, River Forest, ilk, assignor, by
mesne assignments, to Minnesota Mining and Manufacturing Company, St. Paul, Minn, a corporation of Delaware Application March 23, 1955, flerial No. 496,297
14 Claims. (til. 1'5495) This invention relates to decalcomanias, and more particularly to a heat-responsive decalcomania and to the method for transferring an imprint upon a surface.
Decalcomanias are widely known as a means for accurately transferring printed letters, figures and other symbols and designs upon a variety of surfaces, and are especially suitable where the symbol to be transferred is intricate and detailed. While it would therefore seem that decalcomanias or decals are appropriate for the transfer of revenue stamps upon cigarette packages, beverage bottles and similar objects, it has become apparent that other factors make the present decalcomanias unsatisfactory for such purposes. The inadequacy of present decals for these uses results mainly from the fact that the usual decals, afilxed by either heat-responsive or soluble adhesives, may be removed for reuse either by reapplying heat or by dissolving the particular adhesive material.
Therefore, one of the main objects of this invention is to provide a decalcomania adapted to transfer symbols and designs to a given surface in such a manner that the symbols or designs cannot be removed intact from the surface for subsequent reuse. Another object is to provide a decalcomania adapted to be secured to a given surface by a blanketing film of an ink-repelling or resisting substance, such as polyethylene. A further object is to provide a method for transferring a symbol or design, which has been imprinted upon a polyethylene film, to a receiving surface. A still further object is to provide a heat-responsive dccalcomania which is adapted to adhere to smooth, non-porous substances such as cellophane.
Additional objects will appear from the specification and drawings, in which- Figure 1 is a side elevation of a decalcomania embodying my invention; Figure 2 is a side elevation of the same decalcornania in contact with a receiving surface; Figure 3 is a similar side elevation showing a heated iron being applied to the paper backing upon which the decalcomania is mounted; Figure 4 illustrates in side elevation the removal of the paper backing and the transfer of the decalcomania to a receiving surface; and Figure 5 is a top view of tax stamps and serial number imprints sealed upon a receiving surface by a protective coating of polyethylene.
While polyethylene has many properties which make it commercially desirable as :a packaging medium for a great number of materials and objects, it also has the distinctive and heretofore undesirable characteristic of repelling or resisting ink, glue and other adhesive substances. Considerable difficulty has been caused by this unusual ink-resisting property, since identification marks and manufacturers symbols cannot be printed upon polyethylene surfaces in the customary manner.
I have discovered, however, that the ink-repelling property of polyethylene makes this material particularly suitable for use in connection with decalcomanias, and especially heat-responsive decalcomanias. Since the ink will not adhere firmly to a polyethylene surface, an imprint ing or release sheet,
upon a receiving surface which is covered by a coating of polyethylene cannot be removed by reheating and removing the polyethylene film. Any attempt to soften or dissolve the polyethylene covering will produce distcrtion or destruction of the ink imprint and will render the ink impression unsuitable for subsequent use.
In preparing a decalcomania embodying this invention, I first select a grade of sized paper suitable for printing, such as bond paper, book paper, coated paper, kraft paper, colored sulphite paper or the like. Any paper which provides a surface satisfactory for printing purposes may be used.
To the selected paper I then apply an even coating of polyethylene by means of a gravure roll or by any other suitable means. As illustrated in Figure 1, the polyethylene does not penetrate the sized paper but instead forms a separate thermoplastic layer. If a gravure roll is used to apply the polyethylene, small air bubbles approaching miscroscopic size may be formed in the polyethylene film. These bubbles assume a pattern resembling the design upon the gravure roll, thus imparting marks of identification upon the polyethylene-coated paper. In order to prevent the formation of larger bubbles, a defoaming agent may be used. Defoaming agents are well known and readily available in the art, and need not be described in detail here.
The polyethylene may be blended with other substances, such as paraffin and micro-crystalline waxes, which act as extenders for reducing the costs of the polyethylene coatingwithout materially affecting the desirable characteristics of the film and its formation.
To the polyethylene-coated paper 1 next apply an ink imprint, as shown in Figure 1. While I prefer to emloy an ink having a high resin varnish content combined with added synthetic resins, such as phenolic and alkyd resins, other inks having different constituents may be used to produce satisfactory results. As a result of the unique properties of polyethylene, ink will not firmly anchor upon or penetrate into the polyethylene film, but will be Weakly held on the films surface so that subequent transfer of the imprint may be simply and effectively accomplished as will be described presently.
To transfer the ink imprint, I first bring the inkimprinted polyethylene against a surface of cellophane, paper, glass or other material, as shown in Figure 2.. The polyethylene is then softened by the application of heat whichmay be furnished by a heated iron, as in Figure 3, or by any other suitable heating unit. The heated polyethylene becomes a fluid mass which flows over the ink imprint and seals it upon the cooler receiving surface. Figure 4 shows the removal of the sized paper backleaving the ink imprint upon the transfer surface under a protective film of polyethylene.
it should be apparent from the fore oing that polyethylene, unlike the adhesives generally used in connection with decalcomanias, does not serve as a carrier for transferring the ink imprint to the receiving surface, since the polyethylene passes into a fluid or semi-liquid state upon the application of heat to the paper backing upon which the imprinted polyethylene is affixed. The weak forces retaining the imprint upon the polyethylene are broken upon heating so that the polyethylene flows freely and allows the imprint to transfer to the cooler surface Without distortion.
Where a complete transfer of polyethylene from the sized paper release sheet to a receiving surface is desired, I have found that polyethylene having a loW molecular weight produces the most satisfactory results. The phrase low molecular Weight is here used to mean polyethylene having a molecular Weight within the range of 4,000 to 12,900. In particular, I have found that where polyethylene having 'a molecular weight of 7,000 is heated to a temperature of about 100 C. by the application of a heating unit to the back of the polyethylene-coated release sheet, a substantially complete transfer of the polyethylene to a receiving surface results. It is apparent, however, that the particular temperature used to obtain proper transfer of the resin ink and the polyethylene may be varied depending upon the weight of the paper release sheet and the temperature of the receiving surface.
There may be instances, however, where a separate transfer of an ink imprint upon a transfer surface is desired without the accompanying transfer of polyethylene. In such a case, polyethylene having a high molecular weight in the range of 12,000 to 16,000 may be used to produce a satisfactory transfer of the resin ink imprint without the attending formation of a protective polyethylene seal.
When the polyethylene-coated release sheet is heated to a temperature at which the resin imprint becomes tacky enough for attaching to a receiving sheet, high molecular weight polyethylene does not reach a stage of viscosity and tackiness for flowing upon and adhering to a receiving sheet. Upon the removal of the heating element from the back of the release sheet, the high molecular Weight polyethylene quickly returns to a solid state and remains as a film upon the sized paper release sheet.
Thus, where high molecular weight polyethylene is used, all, or nearly all, of the polyethylene remains upon the sized paper backing and only the ink imprint is transferred. I have found that this result is most satisfactorily obtained Where the temperatures are in the range of ll02 C., although it is again evident that temperatures outside of this range may be used, according to the nature of the sized paper release sheet and the temperature of the receiving surface.
While I have spoken of the ink-repelling properties of polyethylene, it is to be understood that I refer to polyethylene which has not undergone special treatment to overcome this unique characteristic. It is necessary that the polyethylene used in conjunction with this invention has the characteristic ink-repelling or resisting properties which have been heretofore considered undesirable.
The decalcomania of the present invention is particularly useful for affixing openwork imprints, such as the tax stamp imprint illustrated in Figure 5, since the imprint cannot be removed and reapplied intact. Frequently, tax stamps are accompanied by serial numbers which have heretofore been applied to receiving surfaces as part of the stamp itself, so that removal of the stamp would also result in removal of the serial number. A particular advantage of my polyethylene decalcomania is that a serial number imprint may be transferred to a receiving surface at the same time but independent from the transfer of a tax stamp imprint upon the same surface and so that the serial number and stamp imprints are a spaced distance from each other upon the receiving surface. Thus, two adjacent imprints may be independently and simultaneously affixed to a receiving surface and sealed upon that surface by a single protecting film of polyethylene.
While I have described the decalcomania product and the steps of my transfer process in considerable detail, it will be apparent to those skilled in the art that these details may be varied widely without departing from the spirit of this invention.
1. A heat-responsive decalcomania comprising a sized paper backing, a film of polyethylene material upon said paper backing, and an ink imprint having substantially no tensile strength and being disposed upon the exposed surface of said film in direct surface contact therewith.
2. A decalcomania comprising a sized paper release sheet, a film of polyethylene material having one surface thereof in contact with said sheet and having a molecular weight no greater than 12,000, and an ink imprint having substantially no tensile strength and being disposed upon the opposite surface of said polyethylene film in direct surface contact therewith.
3. A decalcomania comprising a sized paper backing sheet, a film of polyethylene material having one surface thereof in contact with said sheet and having a molecular weight greater than 12,000, and an ink imprint having substantially no tensile strength and being disposed upon the opposite surface of said polyethylene film in direct surface contact therewith.
4. A decalcomania comprising a sized paper release sheet, a film upon said release sheet of polyethylene material comprising a blend of polyethylene and microcrystalline waxes, and an ink imprint having substantially no tensile strength and being disposed upon the exposed surface of said film in direct surface contact therewith.
5. A decalcomania comprising a sized paper release sheet, a film upon said release sheet of polyethylene material comprising a blend of polyethylene and paraflin, and an ink imprint having substantially no tensile strength and being disposed upon said film of polyethylene and parafiin in direct surface contact therewith.
6. A heat-responsive decalcomania comprising a backing sheet, a film of polyethylene material having one surface thereof in contact with said backing sheet, and an ink imprint having substantially no tensile strength and being disposed upon the opposite exposed surface of said film in direct surface contact therewith.
7. The heat-responsive decalcomania of claim 6 in which said film consists of unblended polyethylene.
8. A heat-responsive decalcomania comprising a sized paper, a layer over said sized paper of polyethylene material having a molecular weight no greater than 12,000 and being releasable in semi-liquid condition from said sized paper upon the application of heat, and an ink imprint having substantially no tensile strength and being disposed directly upon the exposed surface of said layer of polyethylene material, whereby, upon the application of heat to said decalcomania, said layer passes into a semi-liquid condition and said semi-liquid polyethylene material and said ink imprint are adapted to be simultaneously heat released and transferred together upon a receiving surface so that upon cooling said polyethylene material forms a protective seal over the transferred imprint upon 'said receiving surface.
9. The method of affixing an ink imprint upon a receiving surface comprising the steps of coating a sheet of sized paper with a film of polyethylene material, imprinting directly upon the exposed surface of said film, placing a receiving surface in direct contact with the exposed and imprinted surface of said film, heating said film until said polyethylene material reaches a semifluid state, and removing the sheet of sized paper from the imprinted receiving surface.
10. The method of afiixing an ink imprint upon a receiving surface comprising the steps of coating a sheet of sized paper with a film of polyethylene material having a molecular Weight greater than 12,000, imprinting directly upon the exposed surface of said polyethylene film with an openwork ink imprint, placing a receiving surface in direct contact with said openwork ink imprint, softening said polyethylene film to a semi-fluid state by the application of heat, and simultaneously removing the sheet of sized paper and said polyethylene film from said receiving surface to leave said imprint thereon.
11. The method of transferring an imprint upon a receiving surface and covering said imprint with a film of polyethylene, comprising the steps of covering a sheet of sized paper with a layer of polyethylene having a molecular weight no greater than 12,000, applying an imprint upon the exposed surface of said polyethylene layer, placing a receiving surface in contact with said imprinted and exposed surface of said polyethylene layer, softening said polyethylene layer to a semi-fluid state References Cited in the file of this patent UNITED STATES PATENTS Marksberry Aug. 26, 1947 Wittgren July 3, 1951 Wittgren July 3, 1951 Rathke Dec. 11, 1951 Rathke Feb. 24, 1953 Hoover Aug. 16, 1955 Hoover Oct. 25, 1955 Matthes May 22, 1956