Multicolored Heat-transfer Sheet And Processes For Heat Transfer Of Multicolored Ink Impressions

Abstract

Processes for the transfer of multicolored ink impressions by the application of heat and the multicolored heat-transfer sheets which enable these processes to be carried out. A sheet is printed on with a plurality of layers having ink impressions, each layer comprising one of a number of color agents which are respectively distributed in a dry solid resinous binder. The color agents are selected for their sublimation characteristics and said binder includes a quantity of a filler to cause each of said printed layers of inks to be porous to be able to pass the vaporized color agents. The layers are printed in successive order such that the binders have progressively different porosities and/or the color agents possess progressively different sublimation characteristics.

Description

BACKGROUND OF THE INVENTION

The present invention relates to processes for the heat transfer (i.e., transfer caused by the application of heat) of multicolored ink impressions onto various surfaces, and to the multicolored heat-transfer sheets which enable these processes to be carried out, the inks for said ink impressions comprising sublimable coloring agents and binders which contain fillers.

Some processes for the heat transfer of ink impressions onto various surfaces are known, these using transfer paper having impressions of desired pattern. These known processes are limited to the heat transfer of single-colored patterns such as monochromes or line drawings and are inadequate for transfer of a multicolored ink impressions. The reason for this is that, when a heat-transfer process is carried out using transfer sheet for a three-colored pattern printed, for example, in layers of yellow, magenta and cyanine, according to the prior art process, the obtained image transferred onto a receiving surface is quite different from that of the original ink impression. This is due to the fact that, in this heat-transfer process, the cyanine coloring agent, which is printed last and in the upper layer, is transferred without any interruption, whereas the magenta coloring agent in the middle layer is, during transfer, intercepted by the film of the binder for the upper cyanine layer. Further, the yellow coloring agent in the lower layer is interrupted by the two layers of the binders for the cyanine and magenta colors. As a result, an image which is colored differently from the original is obtained.

SUMMARY OF THE INVENTION

It is a general object of the invention to provide improved processes for the heat-transfer of ink impressions of multicolored patterns onto various surfaces as well as the multicolored heat-transfer sheets which enable these process to be carried out, these improved processes and sheets eliminating prior inadequacies.

To achieve the above and other objects of the invention, there are provided processes and sheets to produce a multicolored heat transfer by the printing on a sheet or support of several layers of ink impressions including fillers and sublimable coloring agents of different colors, wherein each layer of ink impressions has a porosity at the time of heat transfer. According to the respective porosity of each printed layer, the sublimed or gaseous coloring agents can penetrate from the lower layer adjacent the support to the receiving surface to transfer. There are two preferred methods to make the printed layer porous. One method is to use a binder including an inactive filler of fine grains, said filler being insoluble in the solute and solvent of the binder and, moreover, incapable of being softened or melted by the transfer heating. The other method is to use a binder including a filler which produces vapor to make the layer porous by heating before the sublimation of the coloring agents, said vapor being inert with respect to the coloring agents.

Another object of the invention is to provide processes and sheets for the heat transfer of ink impressions to effect a transfer the coloring agents of each layer in a uniform manner, and in such a way that the amount of filler contained in the upper layer furthest from the support is richer than that in the lower layer, and/or, the sublimation tendency of the coloring agent in the lower layer is higher than that in the upper layer.

Generally, a multicolored ink impression is provided with color tone by means of a combination and gradation of the three primary colors, that is, yellow, magenta and cyanine. These colors usually printed in the order of yellow, magenta and cyanine, but this printing order is not mandatory. The ink impressions of the layers of yellow, magenta and cyanine are printed with respective plates made by a conventional photographic methods for offset, gravure, relief, or silk-screen printing.

Multicolored ink impressions of this invention are usually printed with three colored layers similarly to a conventional process. A process to produce multicolored heat-transfer sheet by triple printing will next be explained and it will be understood that processes involving more than three printing steps will be accomplished similarly.

In accordance with the present invention, to produce multicolored heat transfer onto a sheet of a material such as, for example, paper, the ink impressions are respectively printed in three layers in the order of yellow, magenta and cyanine. The ink of each layer respectively consists of a coloring agent and a binder including a filler which makes the layer porous. More particularly, the amount of fillers mixed in the binders is larger for subsequently printed layers and/or the coloring agent of ink is more sublimable for each layer which is to be printed earlier (that is, if a layer is to be a lower layer). In other words, yellow ink is to be printed on a support or sheet, this ink consists of a sublimable yellow coloring agent and a binder containing A percent by weight of filler which makes the layer porous. If next a magenta ink is to be printed over the already printed layer of yellow, said magenta ink consists of a sublimable magenta coloring agent and a binder containing B percent by weight of the same filler. If then a cyanine ink is to be printed over the already printed layer of magenta, said cyanine ink consists of a sublimable cyanine coloring agent and a binder containing C percent by weight of the same filler. With respect to the filler percentages, A < B < C.

In another type of multicolored heat transfer a yellow ink is printed on paper, said yellow ink consisting of a yellow coloring agent which is highly sublimable and a binder-containing filler which is capable of making the ink layer porous. Next, a magenta ink is printed over the yellow, said magenta ink consisting of a sublimable magenta coloring agent which is moderately sublimable and the same binder. Lastly, a cyanine ink is printed over the magenta, said cyanine ink consisting of a sublimable cyanine coloring agent which is slowly sublimable and the same binder. Paper with desired multicolored pattern of ink impression is attainable.

Suitable coloring agents for an ink according to the present invention are basic triphenylmethane colors, dispersed dyes, mordant dyes, azo-anthraquinone-triphenyl-methane colors, oxidizing colors and so forth. The chemical constitutions of the coloring agents do not have to be limited precisely. Coloring agents of the proper sublimation characteristics are readily selected.

Serviceable binders are carboxymethylcelluloses, alginic acids and their derivatives, and polymers containing vinyl alcohol, vinyl acetate, vinyl chloride, acrylic acid, meta acrylic acid, maleic acid and so forth.

Fillers of the inactive type are simple inorganic substances and compounds containing at least one atom of silicon, barium, calcium, potassium, magnesium, zinc, iron, aluminum, tin, lead, cadmium, sulfur and carbon, such as sulfates (barium sulfate, calcium sulfate), carbonates (calcium carbonate, magnesium carbonate), silicates (aluminum silicate, magnesium silicate), sulfides (zinc sulfide), and oxides (aluminum oxide, silicon oxide). Also, there can be used organic substances such as synthetic resins (thermosetting resins are preferable), natural resins (such as reclaimed rubber), and natural substances (such as powdered charcoal, powdered cellulose). It is necessary to define the grain size of the filler according to the desired cleanness of the ink impression and; normally, the preferable grain size is less than 5.mu. in diameter.

Preferably, the filler is included in 100 parts of the binder an amount in the range of 50-150 parts by weight. If the binder includes too much filler, the adhesiveness of the ink impression becomes weak, whereas if the binder includes too small an amount of filler, the porosity in the ink impression is too little so that the sublimed vapor of the coloring agent can not pass through from the lower layer to be transferred.

To enable carrying out the transfer of each colored layer equally by varying the content of filler for the respective colored inks, the amount of filler in the upper layer is greater than that in the lower layer. That is, when the multicolored pattern on the heat-transfer paper is printed in the order of yellow, magenta and cyanine, the amount of filler increases for yellow, magenta and cyanine, respectively.

The filler causes the printed layer to be porous so as to enable the same to be penetrated by a sublimed coloring agent. The porosity of a layer furthest from the base surface of the heat transfer paper must be larger to pass the sublimed vapor of the coloring agents of the lower layers. Therefore, the amount of filler in each layer is larger in the layer furthest from the base surface of the heat-transfer paper.

The heat-transfer paper, constituted as described above, is placed on a receiving surface which it contacts with its pattern surface and is heated by pressing the same with, for example, an electric iron set at a definite temperature. The coloring agents printed in each layer sublime and the respective sublimed vapors pass through the porous upper layers over them to transfer to and condense on the receiving surface equally. Thus the same colored image as that of the heat transfer paper is obtained. The transfer is possible for several tens of times, although the transferred image may become gradually inferior.

If the filler is of the type including a foaming agent and the printed layer is made to be porous by heating, the following materials that generally produce nitrogen gas may be used: azo compounds such as azo azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, diazoaminobenzene, barium azodicarboxylate; sulfonyl hydrazide such as benzene sulfonyl hydrazide, benzene sulfonyl hydrazine, toluene sulfonyl hydrazide, diphenyl sulfon-3,3'-disulfonyl hydrazide; nitroso compounds such as N,N-dinitroso pentamethylene tetrazene, N,N'-dimethyl-N,N'-dinitroso terephthalic acid, and inorganic substances such as sodium bicarbonate, ammonium bicarbonate and ammonium nitrite.

In case a filler of this kind is used to equalize the heat transfer of each coloring agent and if the impression of the pattern is printed in the order of yellow, magenta and cyanine and the included amounts of the filler are respectively A, B and C weight percents to the respective binder, then it must be that A < B < C, and A, B and C are preferably from 2 to 30 percent.

The heat-transfer paper, constituted as described above, is placed on a receiving surface which is contacted with its pattern surface and heated by pressing, for example, by means of an electric iron set at a definite temperature. The included foaming agent is thus gasified and the respective printed layers are made porous. Almost simultaneously the coloring agents sublime and transfer or pass through the porous layers of the ink impressions to the receiving surface. In this case, the amount of the included filler in the ink in the upper layer is larger than that in the lower layer and the porosity of the upper layer is larger than that of the lower layer. The sublimed coloring agent in the lower layer can thus transfer through the porous upper layer equally to that in the lower layer and deposit on the receiving surface to form a multicolored image of nearly the same color and shape as that of the colored pattern of the heat transfer paper. Moreover, when the sublimation characteristic of the coloring agent in each layer of the ink impression is different, the coloring agent in the lower layer should be more sublimable than that in the upper layer, so as to equalize the velocity of the transfer onto the receiving surface.

EXAMPLE 1

On printing paper suited for gravure, using gravure plates with three inks of the following composition in the order of yellow, magenta and cyanine, a heat-transfer paper having a multicolored pattern is obtained.

1. Yellow Ink Water-soluble Acrylic Resin 8 parts Water 92 parts Silica (mean particle size: 1-2 .mu.) 5 parts Diacelliton Fast Yellow G (Trademark: Mitsubishi Kasei Kabushiki Kaisha, Ja.) 15 parts 2. Magenta Ink Water-Soluble Acrylic Resin 8 parts Water 92 parts Silica 7 parts Kayalon Fast Rubine B (Trademark: Nihon Kayaku Kabushiki Kaisha, Ja.) 15 parts 3. Cyanine Ink Water-Soluble Acrylic Resin 8 parts Water 92 parts Silica 9 parts Sumikalon Blue FB (Trademark: Sumitomo Kagaku Kabushiki Kaisha, Ja.) 15 parts

Placing the heat-transfer paper printed with the above-described ink over clean white polyester fabric which is closely contacted, and heating the same at 180.degree. C. for 30 seconds, will produce polyester fabric having the same colored image as the ink impression printed on the transfer paper.

EXAMPLE II

On printing paper suited for gravure, using gravure plates with three inks of the following composition in the order of yellow, magenta and cyanine including azodicarbonamide as the filler, wherein the azodecarbonamide is of particles under 300 mesh, which decomposes producing gas at temperatures 190.degree.-200.degree. C., a heat-transfer paper having a multicolored pattern for ink impression is obtained.

1. Yellow Ink Water-soluble Acrylic Resin 7 parts Water 93 parts Azodicarbonamide (foaming agent) 0.7 parts(10%) Diacelliton Fast Yellow G (Trademark: Mitsubishi Kasei Kabushiki Kaisha, Ja.) 15 parts 2. Magenta Ink Water-Soluble Acrylic Resin 7 parts Water 93 parts Azodicarbonamide (foaming agent) 1.05 parts(15%) Kayalon Fast Rubine B (Trademark: Nihon Kayaku Kabushiki Kaisha, Ja.)15 parts 3. Cyanine Ink Water-Soluble Acrylic Resin 7 7 parts Water 93 parts Azodicarbonamide (foaming agent) 1.4 parts(20%) Sumikalon Blue FB (Trademark: Sumitomo Kagaku Kabushiki Kaisha, Ja.) 15 parts

This heat-transfer paper, when placed over clean white polyester fabric and heated at 195.degree. C. for 60 seconds, will produce the same multicolored image on the polyester fabric as that of the original.

EXAMPLE III

Using three inks of the following composition instead of the inks in Example II, a heat-transfer paper is obtained.

1. Yellow Ink Water Soluble Acrylic Resin 8 parts Water 92 parts Dinitrosopentamethylene tetramine 1.6 parts (foaming agent) Diacelliton Fast Yellow G (Trademark: Mitsubishi Kasei Kabushiki Kaisha, Ja.) 10 parts 2. Magenta Ink Water Soluble Acrylic Resin 8 parts Water 92 parts Dinitrosopentamethylene tetramine 1.6 parts (foaming agent) Kayalon Fast Rubine B (Trademark: Nihon Kayaku Kabushiki Kaisha, Ja.) 12.5 parts 3. Cyanine Ink Water Soluble Acrylic Resin 8 parts Water 92 parts Dinitrosopentamethylene tetramine 1.6 parts (foaming agent) Sumikalon Blue FB (Trademark: Sumitomo Kagaku Kabushiki Kaisha, Ja.) 15 parts

By the same condition of the process as in Example II, the same result is obtainable.

EXAMPLE IV

On printing paper suited for printing with inks of the following composition, gravure prints may be printed.

1. Yellow Ink Water-Soluble Acrylic Resin 12 parts Water 98 parts Silica 10 parts p-amino-acetanilide 10 parts 2. Magenta Ink Water-Soluble Acrylic Resin 12 parts Water 98 parts Silica 10 parts 2-Chloro-4-nitro-aniline 10 parts 3. Cyanine Ink Water-Soluble Acrylic Resin 12 parts Water 98 parts Silica 10 parts 1-4-Dimethyl-amino-anthraquinone 10 parts

In the same printing order as indicated above, each ink of above-described composition is charged into respective units of a gravure printing machine and rolled multicolored heat-transfer paper is attained by the known process of gravure printing. Sublimation velocity of the coloring agent used in this printing is measured to show that p-amino-acetanilide sublimes most highly, 2-chloro-4-nitro-aniline sublimes moderately and 1-4-dimethyl-amino-anthyraquinone sublimes most slowly. When said heat-transfer paper is placed over a receiving sheet and pressed with heating, the same colored image as that of the heat-transfer paper is obtained.

EXAMPLE V

Using inks as described in the following table, a multicolored heat-transfer paper is obtained in the same process as described in Example IV.

1.yellow Ink Polyvinylalcohol 20 parts Water 150 parts Soft Clay 15 parts Diacelliton Fast Yellow G (Trademark: Mitsubishi Kasei Kabushiki Kaisha, Ja. 10 parts 2.Magenta Ink Polyvinylalcohol 20 parts Water 150 parts Soft Clay 15 parts Cibacet Brilliant Pink 4BN (Trademark: Ciba, Ltd., Switz.) 12 parts. 3.Cyanine Ink Polyvinylalcohol 20 parts Water 150 parts Soft Clay 15 parts Cibacet Brilliant Blue 3RL (Trademark: Ciba, Ltd., Switz. 12 parts

Sublimation velocities of the above-mentioned coloring agents are measured to indicate that:

Diacelliton Fast Yellow G sublimes most quickly,

Cibacet Brilliant Pink 4BN sublimes moderately,

Cibacet Brilliant Blue 3RL sublimes most slowly. The heat-transfer paper printed with the above-mentioned inks by layers in the above-mentioned order, when placed over a receiving material, and heated with pressing at 180.degree. C. for 60 seconds, will produce the same multicolored image on the receiving surface as the multicolored ink impression of the heat-transfer paper.

As described above, the image on the surface of the receiving material obtained with the process and the multicolored heat-transfer sheet according to the present invention, is very superior in its colors as compared with that attained in the prior art. That is, by heat transfer, quite the same colored image as the original is obtained most clearly and cleanly.

As the heat-transfer process of the invention is a process for producing an image by the sublimation of a plurality of coloring agents, the receiving material may be ordinary paper, artificial resin, fiber material or metal on which not only a single colored but also a multicolored image can be obtained.

Claims

What is claimed is:

1. A sheet adapted for transferring a multicolored image to a receiving surface on the subjecting of said sheet to a transfer temperature, said sheet including a support and a plurality of layers superposed successively on said support, each layer including a respective one of a plurality of coloring agents collectively capable of producing said multicolored image and characterized by respective sublimation characteristics, said layers each having a porosity characteristic whereby said agents when sublimated can pass through to said receiving surface, at least one of the characteristics of the respective layers varying progressively from layer to layer at or below said transfer temperature.

2. A sheet as claimed in claim 1 wherein the color agents have respective and progressively decreasing sublimation characteristics from the layer adjacent the support to the layer furthest from said support.

3. A sheet as claimed in claim 1 wherein the layers have respective and progressively increasing porosity characteristics from the layer adjacent the support to the layer furthest from said support.

4. A sheet as claimed in claim 1 wherein the layers are of a composition adapted to assume the respective porosity characteristics on application of said transfer temperature.

5. A sheet as claimed in claim 3 wherein said layers include a resinous binder in which said coloring agents are distributed and respectively different amounts of filler in the binder, said filler being adapted to make the layers porous.

6. A sheet as claimed in claim 5 wherein the filler is of a material which will not soften or melt at said transfer temperature and wherein there are 50-150 parts by weight of said filler to 100 parts of said binder.

7. A sheet as claimed in claim 4 wherein the filler includes a foaming agent which is activated at approximately said transfer temperature.

8. A sheet as claimed in claim 7 wherein there is 2-30 percent by weight of filler in the resinous binder.

9. A process comprising depositing on a support a succession of layers each including a binder with a respective sublimable coloring agent therein, applying the support with the layers thereon against a receiving surface, and subjecting the support and layers to a temperature at which the coloring agents pass through the layers and deposit on the receiving surface, the coloring agents and binders being made of materials and being so arranged as to have their respective sublimation and porosity characteristics compensate for the different number of layers through which the different coloring agents must pass.

10. A process as claimed in claim 9 wherein the layers are arranged in increasing order of porosity in progression away from said support.

11. A process as claimed in claim 10 wherein the coloring agents in the respective layers are arranged in decreasing order of sublimation characteristics in progression away from said support.

12. A process as claimed in claim 10 wherein the layers are rendered porous on application of said temperature.