US2989413A - Heat transfers - Google Patents

Description

June 1961 R. G. SHEPHERD, JR 2,989,413

HEAT TRANSFERS Filed Oct. 6, 1958 ff PRINTED DESIGN fl-UNOXIDIZED FISCHER-TROPSCH WAX VIIIIIIIIIIM m\\\\\\\\\ fl-PAPER BAcKER Java/war .6 6 ep/Zeruf, 17;: j

United States Patent 2,989,413 HEAT TRANSFERS Ridgley G. Shepherd, In, Weston, Mass, assignor to Dennison Manufacturing Company, Flamingham, Mass., a corporation of Massachusetts Filed Oct. 6, 1958, Ser. No. 765,500 2 Claims. (Cl. 1173.2)

The present invention relates to heat transfers and particularly to improvements in heat transfers embodying a wax release coating, this being a continuation-inpart of Ser. No. 630,276, filed December 24, 1956, which has been abandoned.

The objects of the present invention are to provide an improved heat transfer embodying a wax release layer, to provide an inexpensive heat transfer receptive to high quality printing, to provide a heat trans-fer which can be readily printed on conventional equipment and with conventional inks, and to provide a heat transfer which can be transferred to impermeable as well as permeable surfaces without the need for special adhesive layers over the printed design and without need for sizings on the paper carrier.

Heat transfer products embodying release coatings of wax have long been known but, with the exception of the oxidized wax transfers disclosed and claimed in my copending Patent 2,862,832, granted December 2, 1958, the products heretofore disclosed have possessed severe limitations which have prevented their widespread use. One limitation has been the difficulty in printing due to ink striking into the wax during printing, ink migration into the wax after printing, ink crawling on the wax surface, wax oifset during storage, and picking and embossing of the wax during printing.

A further limitation in prior wax transfers, other than the transfers of the aforesaid patent, has been the faulty transfer of the design, particularly where the surface to be labeled is smooth and impermeable. This faulty transfer is commonly manifested as an ink-split with part of the design transferring and part remaining on the backing or carrier. Attempts have been made to remedy this latter limitation by using heavy wax layers but this increased the distortion of the design during transfer and promoted wax staining of the surface being labeled. Heavy image layers which were intended to split have also been used but fine reproduction detail is impossible with such materials. Images with high strength properties overlayed with adhesive coatings have also been disclosed but these are expensive and are difiicult to apply with conventional printing equipment. Finally, impermeable paper backing or carriers such as glassine and coated papers have been suggested to overcome the drawbacks of wax transfer coatings but such materials are not entirely satisfactory and increase the cost of the product.

Thus ideally a wax release coat should be inexpensive, be effective in thin films as a release agent when coated on inexpensive paper, be receptive to high quality printing, resist strike through or migration of an ink design, have low staining properties, resist picking during printing, show no offset tendency during storage, and be easy to apply on production equipment. None of the prior disclosures, except the aforesaid patent, meet all of these requirements.

According to the present invention, the above require ments and objects are met by a heat transfer comprising a backing and thereon a release coating comprising unoxidized Fischer-Tropsch wax. The coating should have a melting point between about 50 C. and 110 C., and a penetrometer hardness (ASTM D5-52) below about 15 as measured with 100 grams for 5 seconds at ice 25 C, the acid and saponification values being inappreciable.

The present invention may be better understood by reference to the accompanying drawins'g in which SIG. 1 is an isometric view of the present transfer; an

FIG. 2 is a section on line 2-2 of FIG. 1-.

Referring to the drawings, a backing 10 is coated with the aforesaid wax 11 and a design 12 is printed on the exposed surface of the wax. While any convenient backing may be used, paper is preferred for economy. Unlike prior wax transfer disclosures, no sizing is required for the paper before application of the wax and special papers are not required.

The unoxidized waxes of the present invention may be applied to the carrier backing by any convenient method but preferably by the well-known hot-melt process. When using emulsions they should be prepared with alkalies or organic amines since they are formed more easily and give emulsions of low foam-forming characteristics making them easy to apply with conventional paper coating equipment.

The coated paper is printed with a design by conventional printing equipment such as letterpress, rotogravure, and fiexographic presses and with conventional inks including those made from powdered metals. The term design as used herein includes both printing and art work or a combination of both.

The present invention may be more clearly understood by reference to the following examples in which all parts are by weight:

Example N0. 1

FT-200 or FT-BOO, unoxidized Fischer-Tropsch waxes supplied by Dura Commodities, having melting points between C. and C. and a penetration (ASTM D5-52) from a negligible value up to 2 as measured with 100 grams for 5 seconds at 25, the acid and saponification values being nil.

The paper is then printed on the wax side with a nitro-cellulose-based rotogravure ink. After the ink has dried, the design is transferred to MST-53 cellophane by rolling the cellophane, in contact with the design, over a hot plate at 225 F. with mild pressure. The paper backing is immediately removed while hot, leaving the design firmly attached to the cellophane.

After coating with the wax, the paper will have a glossy appearance, will show no signs of tackiness, and will exhibit excellent ink receptivity with sharp outline and good ink-drying properties. Substantially all of the ink design will transfer to the cellophane with only faint staining from the wax without significant distortion.

Example No. 2

Like Example No. 1 except in that the unoxidized Fischer-Tropsch wax is Paraflint RG or Paraflint supplied by Moore & Munger, the melting points of which range between 90 C. and 100 C. and the hardness ranging from a negligible value up to 5, the acid and saponification values being nil.

The products of the above examples will also transfer with good results to material other than cellophane, such as for example, metal foil, wood, fabric, plastic, glass and the like.

The aforesaid waxes are unique in that they afford satisfactory results for most purposes when unoxidized. While ink does not adhere to them so well, for some purposes this is of only secondary importance. Furthermore the ink adhesion properties may be improved by blending in other materials such as oxidized polyethylene and oxidized -FT wax.

2,989,413 3 4 It should be understood that the above disclosure is about 50 C. and 110 C. and a penetrometer hardness for the purpose of illustration only and that the invenbelow about 15. tion includes all equivalents and modifications falling within the scope of the appended claims. References Cited in the file of this patent c aim: 5

1. A heat transfer comprising a backing and thereon UNITED STATES PATENTS a release coating comprising unoxidized Fischer-Tropsch 1,739,581 Ellis Dec. 17, 1929 wax and thereon a printed design. 1,882,593 Hentschel Oct. 11, 1932 2. A heat transfer according to claim 1 further char- 2,219,071 Humphner Oct. 22, 1940 acterized in that said coating has a melting point between 10 2,594,547 Fischer Apr. 29, 1952

Claims (1)

1. A HEAT TRANSFER COMPRISING A BACKING AND THEREON A RELEASE COATING COMPRISING UNOXIDIZED FISCHER-TROPSCH WAX AND THEREON A PRINTED DESGN.

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