US3122093A - Pattern transfer printing elements - Google Patents

Description

' Feb. 25, 1964 R LYNCH ETAL 3,122,093

PATTERN TRANSFER PRINTING ELEMENTS Filed April 12, 1961 fibers Relulively Densely compacted L Fibers Relatively I Loosely Compucted INVENTORS GREGORY R. LYNCH JOSEPH F. TUSCHER ATTORNEYS United States Patent 3 122.093 PATTERFJ TRANSFER PRIN'IHQG ELEMlh TS Gregory R. Lynch, Burlington, and Joseph 1 Tuscher,

Reading, Mass, assignors to The Carters Ink Company, Cambridge, Mass, a corporation of Massachusetts Filed Apr. 12, 1961, Ser. No. 102,555 2 Claims. (Cl. lei-149.4)

This invention relates to printing ad more particularly to the printing of patterns, designs, and outlines for decorative or patterning purposes, or other uses where a deslgn or outline is to be applied on a base surface. The invention consists of a sheet having the desired pattern printed on one side by means of a readily transferable material, and thus provides a convenient and inexpensive means for marking fabrics or construction materials in dressmaking and home crafts, or for applying a decoration or other marking to fixed surfaces, such as in decorating windows and walls.

Present techniques for transferring a design or pattern from a print to a work surface include various reproduction and drafting methods, free hand work, the direct attachment of a thin pattern or template, all of which possess disadvantages such as expense, lack of precision, or in requiring fine skills. Proposals have been made to print a design or pattern on a base sheet which can be laid over the workpiece, and a marking made by applying pressure over the design. According to U.S. Patent No. 482,451, a pattern formed of printers ink mixed with wax and applied to a paper base may be transferred by pressing a stylus along the lines of the design. A similar result may be obtained by tracing a design with a soft pencil on tracing paper, and then retracing on the opposite side with sufiicient pressure to mark an under-lying surface. A practical diificulty lies in the pressure applied from a stylus, which, although only a few ounces of total force comes to a unit pressure which is so very high as to be unsuitable under many conditions. Where the workpiece is fabric, it tends to shift in following the stylus, and its soft working surface will yield, causing the paper base to puncture or wrinkle.

Other similar products are described by Maddock, U.S. Patents Nos. 2,228,286 and 2,233,791 and Kneale, U.S. Patent No. 2,408,147, the former employing a cellulose acetate film base, and the latter a wax impregnated paper base. All require a stylus pressure to eifect a transfer and are accordingly not well suited for use on soft surfaces, or under conditions where high unit pressures are to be avoided.

The transfer sheets of this invention utilize a paper base which carries an outlined pattern of a readily transferred marking material by which a pattern, outline, or design may be printed under very light pressures, such as that attained by rubbing the sheet with a teaspoon or the heel of the hand. In the development of such a prodnot, many problems were encountered which suggested that a sheet of the type sought could not be produced. Transferable marking materials which adhere well to the base do not transfer well under light pressures, While those that are soft enough to transfer easily generally lack decent adhesive properties. Greater difficulties are encountered where a reusable sheet is to be provided for the necessary increased thickness of transferable material tends to result in excessive smudging with soft materials whereas harder materials tend to chip from the base. Experiments with various types of paper indicate that some of the difiiculties could be avoided by employing a paper of higher porosity. That however resulted in a base of greatly reduced transparency which could not be sacrificed because of the need of seeing the underlying surface for proper pattern positioning. Although high transparency and high porosity are contradictory properties, a combination of a paper base composition and readily transferable material was found which would yield the desired product. The transfer material is a relatively soft yet coherent waxy composition containing coloring or pigment, of a type commonly employed in carbon paper. Not all carbon paper dopes, however, are suitable, as some are too soft and smudge easily while others are too hard and do not transfer under the low pressures required for this product.

Adherence and transfer properties were atained by the discovery of a composite paper structure which combined strength, weight, transparency, and porosity in a single sheet. A paper was formulated for use in the sheet of this invention, having a porous fibrous side to which the transfer material would adhere, while being more highly compacted and translucent at the opposite side and inwardly through a sufiicient fraction of the thickness that over-all translucency is provided.

The wax transfer material may therefore be applied so as to penetrate substantially into the body or" the sheet and also to extend substantially from the surface of the sheet, being in the nature of a block printing character securely anchored physically within the fibers at the printed surface. The waxy transfer material is thus firmly secured physically to the sheet without requiring hiherent adhesive properties, and may be formulated to possess those properties giving good transfer under conditions of use.

The backing sheet of this invention may accordingly be characterized as a paper base having its fibers relatively loosely compacted at one surface to provide for penetration of the transfer material (applied in the liquid state) but being over-all more densely compacted and translucent. The degree of compactness may roughly be set forth on the basis of paraffin penetration values, and air resistance values While the over-all transparency can be related to density and weight.

Suitable papers have been found to have the following characteristics:

Ream weight, 20-35 lbs. (500 sheets 24" x 36") TAPPl T-Z-lG-M- LS Porosity (air resistance),

Paraflin absorption, over 15, TAPPI T467M48 The relative compactness of the opposite surfaces may be provided by machine glazing the paper, whereby one surface is calendered or pressed to a more dense condition while the fibers of the opposite surface (the felt side) remain loose and more distantly spaced. Alternatively, yo separate paper furnishes may be employed, first one of stock yielding a transparent sheet, e.g. well beaten relatively long fibers, followed by an over-coating from a secondary head box of less well beaten fibers yielding a more porous base. Numerous other ways may also occur to those sln'lled in the paper making art, by Way of proper selection of paper stock, fiber length and type, degree of beating, degree of cutting, provision of fillers, binders, etc., all of which have definite effects which may be utilized selectively to produce the desired result. It is accordingly contemplated that a paper maker, given specifications as to the type of paper required, may readily produce it without so much experimentation as to amount to invention. The present disclosure confirms that an essentially translucent, relatively heavy weight paper may be made raving one surface loosely compacted and of relatively high porosity (these intrinsically lacking in transparency) without destroying 20-35 seconds, TAPPI *Standard test procedures of the Technical Association of the Pulp and Paper Industry.

5 wh le mixing and grinding thoroughly. The dope is applied as a hot melt at about 180 1 or higher.

The manufacture of the printing elements features the application of a relatively large amount of dope to the base sheet under conditions which assure adequate bonding. This is accomplished by an intaglio printing process employing an engraved print roll 24 in which the desired pattern is deeply etched to provide for an application of dope of at least one mil. Typically the engraving will be based on a half-tone screen of 40 cells per inch separated by a wall thickness of 50a, 100-150,1 in depth.

The roll is heated to apply the dope in its molten condition and the paper is heated to maintain the dope melted during and after application. As illustrated schematically in FIG. 4, the paper base sheet 13 is passed from a feed roll 29, over a hot plate 22, and then between the print roll 24 and an impression cylinder 26. The print roll 24 revolves with its lower portion in a trough 28 of molten dope, the excess of which is removed by means of a doctor blade 39. A pattern of dope corresponding to the engraving on the print roll is thereby applied to the paper 19. The paper 19 next feeds over a second hot plate 32, which keeps the dope molten sufficiently long for proper penetration, then passes over a chill plate 34 to harden the dope, and is finally wound on a take-up roll 36.

Typically the print roll 24 and hot plates 22 and 32 are heated by steam at 5 pounds p.s.i.g. and the chill plate is cooled by water at about 52 F.

A pattern transfer printing element 4% bearing a dolls dress pattern is shown in FIG. 2, and in FIG. 3 is shown its manner of use, wherein the element 40 is laid over a fabric 41 and transfer is efiected by rubbing the back (top) of the element li htly with a spoon 42. As many as 30 prints can be made in this manner.

A printing element formed in the manner described above will have a pattern of dope of a total thickness of about 1 to 2 mils, of which about half (0.5-1 mils) is penetrated into the backing sheet and the remainder projects from the surface. This application is significantly heavier than encountered in the manufacture of ordinary carbon papers, and the product as a whole also differs from ordinary carbon papers in that the dope backing sheet is much heavier, while still being translucent, and of suitably high porosity at the doped surface.

Although this invention has been described with reference to one preferred embodiment, numerous modifications respecting the exact types of paper and dope to be used will occur to those skilled in the art and familiar with this disclosure, and such may be made without departing from the scope of this invention. In particular, dopes will be formulated with varying degrees of hardness or softness within the criteria herein set forth, for specific uses. Where patterns are to be transrerred to a hard surface, such as glass, a softer dope is better than a harder one.

Variations in the paper backing sheet may also be made as long as the requisite properties of translucency, stiffness, and porosity are maintained.

Having thus disclosed my invention and described in detail a preferred embodiment thereof, I claim and deire to secure by Letters Patent:

1. A printing element in the form of a paper sheet base carrying on one side an outlined pattern of waxy marking material transferable to an underlying surface under a pressure of grams applied by a sphere onehalf inch in diameter to the opposite side of said sheet, said sheet being a translucent paper of 20-35 pounds per ream of 500 sheets 24" X36", having a porosity of 20 30 seconds and a paraffin absorption in excess of 15, said marking material being a waxy carbon dope having a penetrometer value greater than 0.25 mm, and applied to a thickness of 1.0-2.0 mils with at least 0.5 mils penetra ing into the surface of said sheet.

2. A printing element in the form of a paper sheet base carrying on one side an outlined pattern of waxy marking material transferable to an underlying surface under a pressure of 100 grams applied by a sphere onehalf inch in diameter to the opposite side of said sheet, said paper sheet being translucent and having fibers relatively loosely compacted on said one side, and relatively densely compacted on said opposite side, with part of said transferable material penetrating partially into the sheet and embedding fibers at said one side without being present at said other side, part of said transferable material also lying outwardly from said one side to form a print contact portion raised at least 0.5 mil from the surface of said sheet.

References Cited in the file of this patent UNITED STATES PATENTS 482,451 Koskul Sept. 13, 1892 1,063,791 Hanington et a1. June 3, 1913 1,911,592 Supligeau et al. May 30, 1943 2,322,445 Huber June 22, 1943 2,382,920 Schaeffer Aug. 14, 1945 2,582,932 Lustbader Jan. 15, 1952

Claims (1)

1. A PRINTING ELEMENT IN THE FORM OF A PAPER SHEET BASE CARRYING ON ONE SIDE AN OUTLINED PATTERN OF WAXY MARKING MATERIAL TRANSFERABLE TO AN UNDERLYING SURFACE UNDER A PRESSURE OF 100 GRAMS APPLIED BY A SPHERE ONEHALF INCH IN DIAMETER TO THE OPPOSITE SIDE OF SAID SHEET, SAID SHEET BEING A TRANSLUCENT PAPER OF 20-35 POUNDS PER REAM OF 500 SHEETS 24" X 36", HAVING A POROSITY OF 2030 SECONDS AND A PARAFFIN ABSORPTION IN EXCESS OF 15, SAID MARKING MATERIAL BEING A WAXY CARBON DOPE HAVING A PENETROMETER VALUE GREATER THAN 0.25 MM., AND APPLIED TO A THICKNESS OF 1.0-2.0 MILS WITH AT LEAST 0.5 MILS PENETRATING INTO THE SURFACE OF SAID SHEET.

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