US2974058A - Method of applying a layer of printing ink plus an additional layer on an underlay - Google Patents

Description

March 7, 1961 L. PIHL 2,974,058

METHOD OF APPLYING A LAYER 0F PRINTING INK PLUS AN ADDITIONAL LAYER ON AN UNDERLAY Filed Oct. 10, 1958 fi/m-formmg layer containing water I Q \PO/JGI' Steam settah/e in/r containing hinder k solvent miscible with water 5/ 76.]

Paper hose Pr/nting with steam settah/e ink contoin/ng' binder solvent m/ec/b/e with water Coating with fi/m-form/ng layer conta/ning water Dispersion Dry/b9 oven G) G) umwlao fi-lhling Pew/17d INVENTGR:

United States Patent Lennart Pihl, Solna, Sweden, assignor to Research Aktiebolag, Solna, Sweden, a corporation of Sweden Filed Oct. 10, 1958, Ser. No. 766,375

6 Claims. (Cl. 11715) It is a known fact that, when printing with so-called steam-settable printing inks, these inks can be fmadeto set or dry by the action of water vapour, mainly that pres-t ent in the air. It is further known that, by lacquering after printing, the gloss of the print can be improved; As regards lacquering, however, it is important that the ink, prior to the application of the lacquer, is absolutely dry, and this has previously applied to all printed surfaces since the inks are otherwise dissolved and bleed. Even when layers other than the lacquer layer have been applied, e.g., a protective layer, it has previously been necessary for the printing ink to have first dried before a further coat was applied.

One method of applying a layer of printing ink plus an additional layer having a lacquering action on an underlay is characterized by the invention in that the type of printing ink used is a so-called steam-settable printing ink, i.e., an ink which can be hardened by applying a liquid, or the vapour thereof, to the ink, and at the same time the additional layer is applied to the printing ink, preferably immediately after the application of the printing ink, this layer at the time of application containing such a liquid as can cause the printing ink to harden or dry and which per se contains substances which form a film on drying and have a lacquen'ng action on the tint. D After application this latter layer conveys liquid or the vapour thereof to the undried layer of printing ink, whereby this latter is caused to harden (dry) under the lacquering layer formed during drying.

Since the application of the printing ink and the filmforming lacquering layer as described in the invention can be effected in what is for practical purposes one operation, the otherwise necessary special drying time for the printing ink, is saved; this being a factor of very great economic importance when using modern printing machinery.

By the word layer or coat in the foregoing is meant each film or the like of the material in question even if the thickness of same, e.g., the thickness of the layer of ink is so small that its character of an actual layer is not especially marked.

This invention makes possible such printing and lacquering of paper, pasteboard or foils made from material other than paper in one operation without the necessity of waiting for the printing ink to dry. Suitable printing inks for use with the invention are those in which resins, dissolved in glycols, serve as the carrier for the colour pigment and which, on the addition of water, are precipitated so that the ink hardens or is dried. Immediately after the application of the printing ink a filmformer, 65

which can be in the form of an emulsion or dispersion of plastic in a water solution, is applied. These filmformers are known in the trade as latices and may consist of either natural or artificial rubber products (elastomers) or plastics of different kinds dispersed or emulsified in the water phase. After the water dispersion has been applied to the ink printed on the underlay by means of Patented Mar. 7,1961

a roller or an airbrush in the usual method by spraying, dipping or in some other way, the printed and lacquered surface is dried by a flow of air or by heating for instance by infra-red-dryers. '5 be applied if a thicker film is required. As a result of the action between the printing ink on the printed surface and the water dispersion'or emulsion of the plastics and as a result of the subsequent drying of the dispersion a nonsmudge surface with a dry layer under the plastic film is 10 obtained. To increase the gloss the plastic treated surface may, if so desired, be caused to pass over a mechanical calendering device. The invention as described abovecan be adopted when printing on a continuous basis 0 when printing individual sheets.

A general principle for the composition of so-called.

steam-settable-printing inks isto dissolve or in some other 5 wayintroduce into a solvent resins, which latter serve as a carrier for the actual colour pigment, and which wholy or partially precipitate together with the colour pigment when the solvent is mixed with water or some other ,liquid. The ink is thus only partially miscible with water .or a similar liquid. According to the procedure described in the invention said liquid is delivered by the still undried additional layer, which must therefore still 2:) contain a sufficiently large content of such liquid and retain it sufficiently long to enable the ink layer to have dried completely.

As an example of the function of the invention a description is given of printing and plastic coating pasteboard.

When using a rotary printing press for letter press or dry offset printing a steam drying printing ink, a so-called steam settable ink composed of synthetic resins as the binder dissolved in glycols and containing pigment are employed. Printing is carried out in one or more colours.

The next immediate stage is to use a roller running in a 35% water emulsion of acrylonitrile polymers to apply a thin film on the ink layer just applied. A heating arrangement with an infrared lamp placed above the newly printed pasteboard dries the emulsion while at the same time a further roller applies an additional layer made up from a 50% water dispersion of a co-polymer of a polyacrylic acid ester. After this layer has been applied the printed material is passed through a drier, after which the printed and lacquered material, in which all the applied layers are dry and hard, can be cut, stamped, sized etc. in later operations.

The invention is not, of course, limited to the example just described. In particular, as concerns the additional -layer to be applied to the layer of ink, there are many alternatives. If the additional layer consists ofelastomers or plastic materials, substances other than those named above can be used either alone or mixed with each other or with the dispersions. Suitable dispersions based upon acrylonitrile derivatives, styrene derivatives, polyacrylic acid derivatives, polyvinyl derivatives such as polyvinyl chloride, and others and combinations thereof.

Moreover, thickeners may be added for instance, casein etc., or antistick materials, as dispersions of paraffin waxes and microcrystalline waxes.

When the additional layer is to consist of a layer for the protection of a package, there are other possibilities depending on the purpose to be served by this layer. For example, the additional layer may serve as a protective layer, for example against corrosion, or serve the purpose of making the underlay impervious to moisture. In all such cases the material of which the layer is to consist is to be so chosen that when the layer is applied to the layer of ink it can re'ease suliicient water or other liquid to harden or dry the ink.

A renewed layer of dispersion can The invention is further illustrated by the accompanying drawings in which Fig. 1 is a diagrammatic cross-sectional view showing the layer of paper, the layer of steam settable ink and the film-forming and ink-setting layer,

Fig. 2 is a flow sheet of the process showing by means of legends the steps of first printing the paper base with the steam-settable ink, then applying the film-forming and ink-setting coating and finally drying,

Fig. 3 is a diagrammatic representation of a machine for successively printing, coating and drying a continuous web of paper.

What I claim is:

1. A method of producing a print on a backing material which comprises applying to the backing material a layer of wet steam-settable printing ink formed of a pigment, a binder and a binder solvent which is miscible in all proportions with water, applying on top of the unset printing ink layer a film-forming layer containing water in a quantity sufficient to precipitate said binder, the film-forming layer also containing a material capable of forming a protecting layer over the ink layer, and drying said layers.

2. The method as defined in claim 1 in which the film-forming layer contains a latex.

3. The method as defined in claim 1 in which the film-forming layer contains polyvinylchloride.

4. The method as defined in claim 1 in which the filmforming layer contains a thickener.

5. The method asdefined in claim 1 in which the film forming layer contains an antistick material.

6. The method as defined in claim 1 in which the material in said film-forming layer which is capable of forming a protective layer over the ink layer forms a water-resistant and corrosion resistant layer.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A METHOD OF PRODUCING A PRINT ON A BACKING MATERIAL WHICH COMPRISES APPLYING TO THE BACKING MATERIAL A LAYER OF WET STEAM-SETTABLE PRINTING INK FORMED OF A PIGMENT, A BINDER AND A BINDER SOLVENT WHICH IS MISCIBLE IN ALL PROPORTIONS WITH WATER, APPLYING ON TOP OF THE UNSET PRINTING INK LAYER A FILM-FORMING LAYER CONTAINING WATER IN A QUANTITY SUFFICIENT TO PRECIPITATE SAID BINDER, THE FILM-FORMING LAYER ALSO CONTAINING A MATERIAL CAPABLE OF FORMING A PROTECTING LAYER OVER THE INK LAYER, AND DRYING SAID LAYERS.

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