Method of printing a pattern on a surface receptive to sublimation printing

A method of printing a pattern on a surface receptive to sublimation dye, in which (a) the back of a carrier foil (1) provided with sublimation dye is caused to adhesively contact an auxiliary carrier (4) by means of an adhesive (5) of greater adhesiveness to the auxiliary carrier (4) than to the carrier foil (1), (b) the pattern to be transferred is cut or punched in mirror-reversed form in the carrier foil (1) without cutting through the auxiliary carrier (4), (c) excess carrier foil (11) is released from the auxiliary carrier (4), and (d) the auxiliary carrier (4) with the applied positive or negative cut or punched pattern (10) is caused to adhesively contact the surface, is pressed and heated. The sublimation foil (9) consists of a carrier foil (1) of paper or plastics whose front is provided with a layer of sublimation dye and whose back is provided with an auxiliary carrier (4) by means of an adhesive (5) of greater adhesiveness to the auxiliary carrier ( 4). The method enables simplified mounting of composite patterns as it directly provides the desired positioning and spacing of the characters.

The present invention relates to a method of printing a pattern on a 
surface receptive to sublimation printing, in which the pattern cut or 
punched in mirror-reversed form from a carrier foil provided with 
sublimation dye is caused to contact the surface by means of an auxiliary 
carrier and is heated for the transfer of the pattern to the surface. The 
term "pattern" as used herein includes arbitrary shapes, such as letters, 
numbers, symbols, ornaments and the like. 
A method of this type is described in the German Patent Specification No. 
2,847,702, according to which a mounting adhesive, provided with a cover 
foil of silicon paper, is applied to the back of the carrier foil. 
According to this patent specification, the desired pattern is cut or 
punched in mirror-reversed form from the cover foil. After removal of the 
carrier foil the pattern is manually placed mirror-reversed on a separate 
auxiliary carrier, which may e.g. be a sheet of paper, by means of the 
mounting adhesive. If the pattern is composed of several characters, these 
are placed one by one on the auxiliary carrier in the desired 
configuration or with the desired spacing. Then the auxiliary carrier with 
the applied pattern is contacted with the surface to which the pattern is 
to be transferred and is heated conventionally, e.g. by means of an iron 
so that the dye sublimes into the surface. 
This method lends itself to the transfer of individual characters, but is 
cumbersome in case of composite patterns, such as sign legends and the 
like, because the characters forming the legends in mirror-reversed form 
on the auxiliary carrier are to be placed manually with great care. 
The method of the above-mentioned patent specification moreover shares a 
drawback with other methods based on heat transfer of sublimation dye, 
viz. frequent formation of shadows on the surface to be decorated because 
the carrier with the applied pattern is not in complete contact with the 
surface. 
The object of the present invention is to provide a method which is not 
vitiated by these drawbacks and which thus ensures perfect contact to the 
surface and obviates the previously necessary intermediate manual transfer 
of characters to an auxiliary carrier, and which moreover enables transfer 
of both positive and negative patterns composed of several characters. 
This is achieved by the method of the invention which is characterized in 
that 
(a) the back of the carrier foil provided with sublimation dye is caused to 
adhesively contact an auxiliary carrier by means of an adhesive of greater 
adhesiveness to the auxiliary carrier than to the carrier foil, 
(b) the pattern to be transferred is cut or punched in mirror-reversed form 
in the carrier foil without cutting through the auxiliary carrier, 
(c) excess carrier foil is released from the auxiliary carrier, and 
(d) the auxiliary carrier with the applied positive or negative cut or 
punched pattern is caused to adhesively contact the surface, is pressed 
and heated. 
The invention also relates to a sublimation foil with an auxiliary carrier 
for use in this method, said sublimation foil being characterized in that 
it consists of a carrier foil of paper or plastics whose front is provided 
with a layer of sublimation dye and whose back is provided with an 
auxiliary carrier by means of an adhesive of greater adhesiveness to the 
auxiliary carrier. 
The method of the invention enables decoration of surfaces of all possible 
materials receptive to sublimation dyes and capable of resisting the 
heating which is necessary for the sublimation and which depends upon the 
sublimation temperature (range) of the selected dye, in particular. 
Examples of such materials include 
(1) textiles of synthetic and/or natural fibres optionally treated to 
ensure the required heat stability, 
(2) thermoplastic materials, such as polystyren, polyethylene, 
polypropylene, polyvinyl chloride, vinyl chloride or vinyl acetate 
copolymers, styrene butadiene copolymers or ABS polymers, polyamides, 
acrylic polymers, such as polyacrylonitrile and polyacrylates, polyesters, 
polyurethanes, etc., 
(3) thermosetting materials such as epoxy resins and epoxy composite 
polymerisates, amino plastics, such as melamine plastics and carbamide 
plastics, and a large number of plastics materials which can be made 
heat-settable by cross-linking, such as polyesters, polyacrylates, 
polyurethanes, etc. 
Even the objects to be decorated may be made of the above-mentioned 
plastics materials or may be provided with coatings of such materials, 
e.g. by lacquering. 
According to their nature and use the plastics materials may be 
cross-linked or not, reinforced, e.g. with glass fibres, and they may be 
pigmented, if desired. 
Examples of decoration objects are: 
Injection moulded or extruded objects of thermoplastic materials, such as 
glass fibre reinforced polyesters. 
Aluminium sheets lacquered with a pigmented ground lacquer, e.g. a 
polyester of polyurethane lacquer, and a transparent top coat lacquer, 
e.g. a polyurethane lacquer. 
Self-adhesive polyester or acrylic foil. 
Textiles of cotton or wool admixed with synthetic fibres.

In FIG. 1 the numeral 1 designates the carrier foil which is to be of a 
grade suitable for application of liquid sublimation dye, such as glazed 
paper, or cross-linked plastics foils e.g. of polyesters, in particular 
polyethylene terephthalate (Melinex.RTM., Mylar.RTM.), melamine or acrylic 
plastics. 
Sublimation dye is applied preferably by rotating screen printing as 
illustrated by the roll arrangement 2 or by offset printing, photogravure 
or serigraphy. 
The preferred sublimation dye type is serigraphy dyes, e.g. those available 
from Ciba-Geigy, Widerhold or Lithotex. 
After the application of dye the carrier foil is dried by the drier 3 to 
prevent permeation of the dye to the back of the foil. 
The auxiliary carrier 4, which may be a foil of the same grade as the 
carrier foil 1, is provided with adhesive as illustrated by the roll 
arrangement 5. 
The employed adhesive must not dissolve or enter into the sublimation dye, 
and it must be temperature resistant from 0.degree. and up to the 
sublimation temperature used, in practice up to about 220.degree. C., for 
a period of time sufficient for the sublimation of the dye to take place, 
in practice at least 2 minutes. The employed adhesive must moreover not 
adhere permanently to the back of the carrier foil, but must admit of 
being firmly fixed to the auxiliary carrier. This fact must of course also 
be taken into consideration in the selection of foil grades for auxiliary 
carriers of carrier foil. The above-mentioned criteria are met e.g. by 
adhesives of the polyurethane, acrylic or silicon type which are 
preferably cross-linked. 
The adhesive is heat-set at 6 so as to be firmly fixed to the auxiliary 
carrier 4. 
The foil 7 is then ready to be assembled with the carrier foil. 
Instead of the treatment illustrated at 4, 5 and 6 certain commercially 
available finished adhesives may be used, if desired, e.g. the heat 
application tape available from 3M. 
The back of the carrier foil 1 is adhered to the auxiliary carrier 7 by 
means of the fixing rolls 8. 
The assembled foil laminate 9 is now placed e.g. in a flat or round plotter 
whose guide head is provided with a knife or laser beam cutter unit to 
produce characters or patterns. The plotters are coupled to a computer 
which is programmed to the desired result. 
The above-mentioned result can also be obtained by traditional punching 
tools, which may likewise be programmed, if desired. 
Characters or patterns are punched or cut in mirror-reversed form and 
without cutting through the auxiliary carrier as illustrated at 10 in FIG. 
2. 
According to whether positive or negative characters or patterns are 
desired, excess carrier foil is removed as illustrated at 11 in FIG. 2, 
which shows a positive pattern. 
After removal of excess foil 11 an adhesive face 12 appears, which may in 
turn be used for fixing the composite characters or patterns on a 
decoration object which is designed for the purpose and to which the 
remaining sublimation dyes are to be transferred. The transfer takes place 
in a manner known per se, e.g. in a heat press at 180.degree. to 
220.degree. C.