DE2058581A1 - Process for the production of direct images or printing forms for serigraphy or screen printing and with this produced image or corresponding printing form - Google Patents

Description

November 27, 197ο P 4o67 - rebit

The Argon Service ltd. S.r.l., Milan

Process for the production of direct images or printing forms for serigraphy or screen printing and an image produced with this process or corresponding printing form

The invention relates to a method of manufacture of direct images or printing forms for serigraphy or screen printing and with this Process produced image or corresponding printing form.

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109828/1257

The present invention "relates to a new one Process for the production of a direct serigraphic image, with a die or stencil that has properties similar to those of the dies or stencils in terms of clarity and accuracy is comparable to those used for the production of indirect serigraphic images. The present invention moreover relates to a direct serigraphic effect achieved with this new process Image.

As is known, an image or a printing form for screen printing or serigraphic printing consists of a frame made of wood or metal or of another suitable material on which a fabric made of silk, synthetic fibers or some other material is stretched, the uniform and uniform , contains more or less W dense meshes. It is also known that the custom of producing the template or stencil, which represents the drawing to be reproduced by printing, directly on the fabric by photochemical processes, so-called direct images or printing forms being obtained, is common practice. These direct pictures oda; Printing forms differ from indirect images or printing forms in the fact that in these latter the matrix or stencil is also used.

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half of the image and then applied to the fabric and fixed to it. For the production of a direct image (printing form), emulsions or gelatine or light-sensitive solutions (hereinafter referred to as called "emulsions") that have been sensitized or sensitized to a greater or lesser extent and that have been made by hand be painted on the fabric stretched on the frame or, as an alternative, used beforehand coated with light-sensitive and more or less sensitized or sensitized emulsions Fabrics as they are commercially available today.

The photosensitive emulsion in the sensitized state has a property of being insoluble in water when exposed to a strong light source for a period of time. One achieves a direct serigraphic Picture by making use of the following property: You put the with for a few minutes the above-mentioned photosensitive emulsion which is sensitized or sensitized and dried has been, coated image of the action of a strong light source, whereby those parts of the Protects fabric against the effects of light, which carry or form the figure or drawing that you achieve wishes. If you now expose it to the action of light, the emulsion will be in the areas that are against the

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Have been protected from exposure to light ^ easily in lukewarm Dissolve water, exposing the meshes of the fabric that were previously closed by this emulsion while the meshes of all other parts of the fabric that have been exposed to light, remain closed by the emulsion as it will not dissolve.

One uses the same principle for the production of an indirect image (printing form) by one prior to the emulsion-impregnated image, an image generally made of clear plastic material Exposing the wearer to light previously has been coated with a similar emulsion, which is a PiIm in the dry state, and by then this PiIm or this membrane is transported and applied to the fabric of the image and it makes it stick to this and finally by making the temporary support of transparent or translucent Plastic material removed.

A direct image has the advantage over an indirect image that it has a much greater strength, which allows far greater tensile effects, and that it also has a greater accuracy of reproduction from the first to the last copy. This is down to the fact

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thing attributed to the fact that the photosensitive, directly emulsion coated on the fabric passes through the fabric and, when dry, between firmly anchored in the Masia, in such a way that they coexist with them the latter forms a single piece.

In the case of the indirect image, however, the matrix or stencil is - as has already been mentioned above - off a light sensitive eilra or cuticle applied to the fabric in general after it has been exposed to light has been applied and adhered to a single side of the fabric itself without the emulsion of which it is made and which is in the dry state passes through the mesh and attacks the other side of the fabric.

While a direct image is much more resistant to an indirect image, it is clearly inferior to it in terms of clarity in reproduction. Indeed, it is known to all those skilled in the art of screen printing that when the stencil or stencil of a direct image is developed with water and after it has been exposed to light, small perfectly straight and clearly 4e.finie.rJtn! lines Qd ^ r to show dashes

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can, neither on the die or stencil itself, nor on the subsequent print, rather more or less sawtooth delimited dashes or lines or on in all cases does not get particularly well-defined lines or strokes with slightly blurred boundaries. These Appearance is attributable to the fact that the emulsion, which is formed during development with water has impregnated in the subsequent drying phase has a tendency to contract and collect in individual places, possibly due to the appearance the surface tension near the points where the weft threads and the warp threads cross.

On the other hand, when developing an indirect image, the stencil or stencil, which is simply on the fabric, dries supported, in the phase following the development, without participating in the above phenomenon, or by him to be affected, due to the fact that in this case the fabric is not a fitting for the die or Template, but merely represents a carrier on which the die rests without the mesh being impregnated have been: It is clear that the membrane which represents and forms the matrix is the phenomenon of tension, which is seldom exercised by the mesh, is not experienced or

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is influenced by it, as is instead the case with the permeable and moist emulsion, which the meshes impregnated in the case of direct imaging. Because of this, if you look at the same slide, you will on a cuticle for achieving an indirect Applying the image, a die or stencil is obtained that is much more precise and in its boundary lines is more precisely defined, so you will get a much clearer print for this reason.

The conclusions drawn from the above are clear and well known to all experts: If you have big requires strong tensile stresses and the clarity of the reproduction is not the main feature, one will give preference to direct images, which are much more resilient and otherwise less expensive than that indirect images are; if, on the other hand, the main characteristic or main requirement is the clarity of reproduction and looks at the straight, precisely defined course of the lines and dashes (e.g. in the case of printing electrical circuits), preference will be given to the indirect image (printing form), even if this has a shorter lifespan and costs more.

The main aim of the present invention is to To create a method that has the disadvantage or the error of the sawtooth-shaped delimitation of the lines and

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Lines (running out of the delimitation lines) and the lack of clarity in the direct images or printing forms are eliminated and it also allows the advantages of the direct images (greater resistance, lower costs) to be added to the characteristic feature previously for the indirect images, namely the clarity of the Reproduction and the straight course of the reproduced lines and lines. These and other purposes ^ äe.T present invention will occur to those skilled in the art from the following description and the subsequent claims.

The process of obtaining a direct serigraphic image (printing form) with a die that has improved Has properties with regard to the clarity of the reproduction is, according to the invention, essentially by the Fact that the outer surface of the . light-sensitive emulsion, which may have been sensitized or sensitized, and which on the Screen printing fabric has been painted on at the points on which the formation of the die or template is provided, is anchored in that one is on this Surface makes a continuous surface or a membrane temporarily adhere intimately, which consists of a impermeable and insensitive to water Material exists - which is why during the development

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operation with water and the subsequent drying phase - Can prevent this outer surface of the emulsion from contracting and as a result of this the unwanted sawtooth-shaped parts on the die or stencil Form boundary lines.

In particular, the method according to the invention is through the fact marked, dt. it was made up of several steps consists:

1. Impregnation of the serigraphic fabric with a photosensitive emulsion that has been sensitized or sensitized, or neither, in such a way that a uniform emulsion layer is formed on the outer surface of this fabric obtained, which in the dry state has a minimum thickness which is not less than Io A is;

2. possibly sensitizing or sensitizing them photosensitive emulsion using the usual method;

3. Anchoring the outer surface of this even layer of sensitized or sensitized emulsion with the help of a skin or a layer in the dry state of a transparent lacquer,

109828/1257

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which is impermeable and insensitive to water, this layer on a suitable Carrier is applied;

4. Removal of the base of the lacquer layer if the base is not transparent;

5. Then the fabric is disguised ("mascheratura") according to the usual methods, all that exposed to light, everything developed with water and then dried;

6. Finally, the layer becomes transparent paint removed.

For a better understanding of the subject matter of the invention, reference is made to the figures of the drawing. Show it P where:

1 shows a section of a serigraphic fabric which has been impregnated in the usual known manner with a light-sensitive emulsion for the production of a direct serigraphic image, in a side view in a vertical section,

Fig. 2 shows the position of the pellicle or film relative to the tissue in achieving a known one

109828/1257

usual indirect serigraphs

Image also in a side view

in a vertical section in a schematic representation,

Fig. 3 shows a "known" by means of a direct this graphic image generated print in plan view,

Fig. 4 shows the same pressure as in Pig. 3, either with a usual indirect serigraph Image or with a direct serigraphic image, according to the process has been manufactured according to the invention,

5 shows a section of a serigraphic fabric, which is impregnated with a photosensitive emulsion by the method according to the invention has been, in a side view in a vertical section,

Pig. 6 shows a section of a transparent membrane and the corresponding carrier used in the method according to the invention can, again in a side view in a vertical section,

Fig. 7 - a representation corresponding to that according to

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I ¹ Ig. 51, however, with the transparent membrane and the corresponding support arranged and anchored on the outer surface of the emulsion, and

Pig. 8 shows a representation corresponding to that of Pig. 7 »whereby however the carrier for the clear skins have been removed.

Pig. 1 and 2 show the usual processes for the production of serigraphic or direct or indirect images intended for screen printing. These figures are listed here only for the purpose of comparison with the subject matter of the invention; they never relate to known methods with which those skilled in the art are familiar. As from a direct comparison between Pig. I and Pig. 5 shows the photosensitive emulsion 1, which is painted on the serigraphic fabric T (Pig. 5), shows a uniform thickness on the outer surface of this fabric, which in the dry state is significantly greater than the thickness of the photosensitive emulsion I ¹ , which is shown in FIG in the usual way and with the known methods on the serigraphic fabric T ¹ (Pig. 1). The optimal thickness of the emuleion in the dry state changes according to the fineness of the tissue and is generally between lo./'unä 5ο- ·. contain.

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After the brushing on the fabric has been finished has been shown as described above and in Pig, 5 is, it is important to prevent the development of water during the operation with which on the Operation follows, which consists in exposing the matter to strong light before dressing up with the slide up to the upper outer surface of the emulsion layer the above-mentioned phenomenon of surface tension is found, due to which the water-impregnated emulsion from the threads of the The weft and the warp is withdrawn, so to speak, and strives to be close to their crossing points to accumulate and collect, then the well-known phenomenon of the sawtooth-shaped and non-linear course of the lines or lines and the running out of the boundary line either on the die or stencil or on the Printing takes place, as can be seen clearly from FIG. 3, in particular when this figure is compared with FIG. This phenomenon is eliminated and annulled according to the method according to the invention by removing the external Area of the emulsion layer due to temporary adhesion anchored to another surface that is not in the least affected by water during the development operation will.

For a better understanding of the invention, the following

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the only for explanation an embodiment. of the method according to the invention with reference to Figs .

A nylon fabric T No. 45 (I2o stitches per one as linear Measure) is based on a usual frame for ser! Graphic Pictures are stretched and on this tissue becomes a light-sensitive non-sensitized emulsion painted on

™ or applied which is of the kind used in stores known by the name "Argonsol" to make this way on the outer surface of the fabric, after the emulsion has dried, a layer about 2o (t (Pig. 5). The emulsion layer is then sensitized or sensitized by touching them wetted with the help of a sensitizer based on ammonium dichromate in aqueous solution with a concentration of 16og / liter - in the ratio of

P 1: 6- is made with denatured ethyl alcohol, the Buty lace did in a ratio (proportion) of 5 1 ° is supplied. Immediately after the sensitization and before the surface of the wetted emulsion has dried, a dry film 2 of a transparent Nytrocelulose lacquer with a thickness of applied about 2o _iu , (which is in the dry state) and

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on a polyester support 3 with a peck of 5o-painted and is plotted (Fig. 6, 7). The intimate adherence of the 3? Film 2 to the emulsion layer 1 is carried out using a spatula to remove the excess liquid in this way. After completion of these first phases, a complex (Pig. 7) is obtained, which consists of the serigraphic fabric T consists of that with sensitized and with a cellulose film and a corresponding carrier 3 coated emulsion is impregnated.

The complex is then allowed to dry. the drying is accelerated with warm air, and then you remove the polyester carrier 5 by simply lifting it off, with the gelutose film 2 flawlessly on the surface of the underlying emulsion 1-anchored (Fig. 8), on the clear cellulose film 2 a slide is applied in such a way that it is J

contact, and the goose then becomes a strong one Exposed to light, e.g. exposure to light originating from a lamp with a three-phase arc of 20 A. After exposure to light has finished, the image is developed in lukewarm water, revealing from the inside of the image such that those parts of the emulsion which, since they have not been exposed to light, beef because they have been shielded by the slide & .iri, water soluble

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remained βUvI, removed. Then it is dried. After drying has ended, the transparent cellulose film is removed from the surface of the illustration - and this to allow the ink or ink to penetrate - by dissolving it with a suitable solvent or solvent, e.g. butyl acetate.

In this way a direct serigraphic was obtained Image with a die, the contours of which are perfectly accurate and absolutely no sawtooth-shaped or leaked Have boundary lines that allow prints of absolute To achieve clarity, of a clarity that corresponds to that obtained with the indirect serigraphic Images as shown in Fig. 4 is obtained.

In the above exemplary embodiment, a non-sensitized photosensitive emulsion has been used, but it is clear that any other emulsion which has already been sensitized can be used and in this case the anchoring of the cellulose film 2 to the layer 1 is effected by the surface of this layer 2 is wetted with water or with a mixture of water and alcohol to which a small amount of the solvent for the gelulose films has been added. A material which is also different from polyester and which is transparent can be used as the carrier 3 of the cellulose film 2

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and in this case exposure to light can be avoided can also be carried out and effected when the carrier is still in position, and then the wearer can simultaneously with the transparent one Remove the oil film 2 or immediately beforehand,

In addition, any suitable sensitizer can be used to sensitize the emulsion, e.g. in addition to the ammonium dichromate already mentioned Potassium dichromate and others or a mixture of dichroic acids or a solution of organic diazo compounds, as the result of the present process is independent of both on the type of sensitizer that is used as well as on the fact that the emulsion is in front or is sensitized after spreading it on the picture.

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Claims (6)

ν 0 5 8 5 8 Expectations (JLl method for making direct images or printing forms for serigraphy or screen printing, characterized in that the outer surface of the light-sensitive emulsion that may be sensitized P and streaked out on the serigraphic fabric is, at the points where the formation of the die or, template is provided, is anchored in that a skin-like continuous surface her is temporarily made to adhere closely, this membrane being made of a material opposite Water is impenetrable and insensitive, which is why during the operation of developing with water and the subsequent drying phase, the contraction of the outer surface of the emulsion and the subsequent formation on the die or stencil of undesirable sawtooth-shaped or dissolving boundary lines is prevented. 2. The method according to claim 1, characterized in that that the 3erigraphic fabric with a light-sensitive An emulsion is coated which is sensitized or not, in this way to achieve a uniform emulsion layer on the outer surface of this fabric, which in the ¹ ..> rx ** ri Ql ® -19 - J ^ ^vkih Ί 0 9 8 2 8/1 2 5 7 ¹¹¹ ^ ¹ """ W 1!!"Θ; ¹ ! "S * r dry state has a minimum thickness not less than Io, - [. 3. The method according to claim 1 or 2, characterized in that the continuous surface or the Skin that is used for anchoring, transparent and is transparent. 4. Verfaliren according to any one of claims 1 to 3, characterized in that the continuous surface or the membrane which is used for anchoring and is transparent, advantageously made of a film of cellulose nitrate with a thickness of not less than Io ^ in the dry State which has been previously applied to a support made of plastic material or plastic material, which can be easily removed when the membrane has come to perfectly adhere to the outer surface of the photosensitive emulsion. 5. The method according to any one of claims 1 to 4, characterized in that one to the temporary intimate adhesion the transparent membrane used for anchoring on the outer surface of the photosensitive emulsion to effect the emulsion itself with water or with a mixture of water and alcohol or even with the sensitizer the emulsion in an aqueous or alcoholic solution '■ "" - ■ - ■ · ■ - 2o 1üaö28 / 1257 _R , _n _ 1 ■ wets a solvent, possibly in small proportions of Prozerite for there, '3 skins added .ir-'t, after which you can The skin and the associated vehicle are applied to the emulsion brings up each perfect touch between the two Surfaces received and then everything left to dry. _ 6. The method according to claim 4, characterized in that that the carrier made of plastic material after drying is removed by simply lifting it off. 7. The method according to any one of claims 1 to G, characterized in that it consists of the following steps t a) one impregnates the serigraphy before fabric with a photosensitive emulsion that sensitizes It is or is not necessary to produce a uniform surface in this way on the outer surface of this tissue Emulsion layer obtained with a minimum thickness in the dry state of not less than Io _(< 2U b) possibly the light-sensitive emulsion is after sensitized according to the usual procedures; c) one anchors the outer surface · this uniform one Layer of the sensitized emulsion with a dry skin layer from a 1üaö28 / 1257 BAOORIGINAU " ^l ! ^l |: ¹ "" ^{| l} Ί! lll | ^{l | l} j |]! || p | l ^| | ^l '!! | ^l !" !! ^| 1ll ^l ΊII! L! Ilj " ^{l |} l !! | ^l || ^l Γ ¹¹ I ¹¹ I ¹ I ¹¹ I i '"¹; ¹ '! ;; \ i! ||! l J ·; ·, ■■■ "! ι. ■ '.'! ||| ΐΐ |! | ΐι. ■■■■■. ■ ί. ''.'iiii'ni" ,. ini ¹ ιί | n ··; _; . | j,. < transparent, impermeable and water-insensitive varnish, which is attached to a suitable carrier; d) this support for the membrane is removed from lacquer if the carrier is not transparent; e) one then dresses (covers) the arrangement in in a known way (with the slide) everything is exposed to the action of light, developed with water and dries in each case, likewise in a manner known per se; f) the membrane is removed from the transparent varnish, 8. The method according to claim 4, characterized in that the carrier made of plastic material consists of a film made of polyester, which is advantageously transparent and has a thickness between 5ctyund 10o _fl . 9. The method according to claim 7, characterized in that the removal of the cuticle of transparent lacquer takes place by that this layer or this Hautchen at solves einam suitable Lösungsrait, dao, for example, butyl acetate ana can exist when the layer ^ imim QAt: 10.9 828/1257 - 22 - 205858 Ί or the membrane is made of cellulose nitrate, Io. Image (printing form) for the Serigraphis or the Screen printing, characterized in that it is with the process according to any one of claims 1 to 9 is produced. 1 U y 8 l 8 / i 2 5 7