EP1749676B1 - Process and installation for making a printing surface, specially for ink-jet printing, paper sheet and article - Google Patents

Abstract

Production of a printable surface involves impregnating a paper sheet (10), which absorbs liquid synthetic resin over its whole thickness, with the resin (14) from one side (12) of the sheet, so that the resin does not penetrate through the whole of the sheet and the other side (16) remains free of resin. Independent claims are included for: (1) a sheet of paper (10) (specifically with a stretchable structure) having a printable surface (16), obtained by partial impregnation with resin as above; (2) a printable article, at least partially coated with a paper sheet as above; and (3) apparatus for carrying out the process, where the opposite side of the sheet is impregnated with a barrier liquid, consisting of two spaced, opposite liquid application devices between which the sheet passes, liquid synthetic resin being applied to one side of the sheet and barrier fluid to the other.

Description

The invention relates to a method and an apparatus for producing a surface which can be printed in particular by means of an ink-jet printing method. The invention further relates to a paper web having a surface that can be printed in particular using an ink-jet printing method, and an article that can be printed in particular using an ink-jet printing method.

Ink-jet or inkjet printing methods allow the formation of almost any pattern in, depending on the hardware and software equipment, high quality and precisely predetermined orientation to a surface to be printed. For example, the patterns that have the look of precious wood surfaces can be created by scanning from a master or synthetically with graphics programs. Contrast, color, size, etc. of the patterns can be varied by means of known electronic data processing methods and adapted to the respective surface.

For the optical quality of the pattern, which can also be designed as a homogeneous coloration, the type and quality of the surface to be printed is relevant. Thus, it is known, for example, plates or sheets or other items from inexpensive using hardened resins or other binders solidified press materials, such as fiber or particle materials to produce and, optionally after a grinding process to provide a primer and then to print. It is also known to laminate surfaces of such inexpensive basic body with films, such as synthetic resin films, or completely resin-impregnated papers and printed. For a satisfactory print quality, it is expedient to provide this plastic-containing surface before printing with a primer or roughen, because of the poorly wettable or plastic-containing surfaces, so that the dyeing liquid adheres properly.

From the DE 197 15 268 A1 is a thin film of a base paper with pigment coating on the printing side of the base paper is known, which is impregnated starting from the opposite side of the pigment sheet pigment with a impregnating resin. The pigment coating forms a barrier layer for the impregnating resin, so that the impregnating resin is not up to the printable Surface can push forward. The pigment coating influences the physico-chemical properties of the raw paper surface which are decisive for the quality of a printable pattern by the inkjet printing process, so that the printability is changed compared to an untreated base paper.

From the DE 199 55 081 C1 A base paper for a recording material for ink-jet printing method is known which contains 5 to 55% by weight of a filler, is free from engine sizing agent and impregnated with an impregnating resin, wherein the resin receiver from the impregnating resin is adjusted so that the base paper on the back of a liquid absorption of at most 20 grams / m ² . The back side is the side opposite the sides to be printed. The resin can be applied from one side or from both sides. In any case, the surface to be printed is more or less impregnated with resin.

From the US 4,198,446 and the EP 0 639 865 A1 Devices are known with which at the same time on the two sides of a (paper) web, a liquid is applied.

The invention is based on the object to provide with an ink jet printing process printable objects, on the surfaces of which produce producible patterns, especially in terms of appearance highest quality requirements.

A first solution to this problem is achieved by a method according to claim 1.

Claims 2 and 3 are directed to two advantageous embodiments of the method according to the invention, with which is achieved that the printing side of the paper web remains wholly or at least substantially free of synthetic resin.

With the features of subclaim 4, the side of the paper web to be printed can be adapted to particular requirements.

With the features of claim 5 flexibility in the further processing of the paper web is achieved.

Claims 6 to 8 are directed to advantageous ways in which a paper web according to the invention can be applied to a base body.

Claims 9 and 10 characterize a paper web according to the invention.

Claim 11 indicates a printable article provided with a paper web according to the invention.

The claim 12 whose preamble to the US 4,198,446 is characterized, a device for carrying out a method according to the invention.

The invention provides surfaces which correspond to conventional paper surfaces in terms of their properties required for printing, which are optimally adapted to the desired printing result in a manner known per se by the selection of the paper and the dyeing liquid and optionally a pretreatment of the surface to be printed. Thus, the invention allows the immediate implementation of the possibilities created by electronic data processing and the highly developed ink-jet or inkjet technology to be applied directly to the printing of objects.

The invention is suitable for substantially all types of base papers having absorbency or capillarity. Coated papers, fine papers and base papers can also be used. The basis weight is, for example, 30 to 300 g / cm ² . No separate tube receiving layer is required.

The top layer of a paper web according to the invention is both paintable and laminatable. The resin layer is an integral part of the paper web according to the invention. The resin can be a conventional impregnating resin in the paper industry, for example from the group of diallyl phthalates, epoxy resins, urea-formaldehyde resins, uric acid-acetyl ester copolyesters, melamine-formaldehyde resins, melamine-phenol-formaldehyde resins, phenol-formaldehyde resins. Resins, poly (meth) acrylates or unsaturated polyester resins.

The invention is explained below with reference to schematic drawings, for example, and with further details.

Figur 1

eine schematische Querschnittsansicht durch eine einseitig mit Kunststoff getränkte Papierbahn,

Figur 2

eine perspektivische schematische Ansicht einer Vorrichtung zum einseitigen Beschichten einer Papierbahn,

Figur 3

eine schematische Schnittansicht eines erfindungsgemäßen mit einer Papierbahn versehenen, dann bedruckten und dann mit einer Schutzschicht versehenen Gegenstandes,

Figuren 4 und 5

Darstellungen zur Verdeutlichung unterschiedlicher Kaschierungsmöglichkeiten von Grundkörpern,

Figuren 6 und 7

schematisch eine Vorrichtung zum zweiseitigen Tränken einer Papierbahn mit Flüssigkeiten,

Fig. 8

verschiedene Möglichkeiten zum Aufbringen einer Papierbahn auf einen Grundkörper,

Fig. 9

unterschiedlich konkavierte Grundkörper mit aufgebrachten Papierbahnen und

Fig. 10

unterschiedlich bewegbare Druckköpfe zum Bedrucken von Gegenständen.

They show:

FIG. 1

a schematic cross-sectional view through a one side impregnated with plastic paper web,

FIG. 2

a perspective schematic view of an apparatus for one-sided coating of a paper web,

FIG. 3

a schematic sectional view of an inventive provided with a paper web, then printed and then provided with a protective layer object,

FIGS. 4 and 5

Representations to illustrate different possibilities of lamination of basic bodies,

FIGS. 6 and 7

schematically a device for two-sided impregnation of a paper web with liquids,

Fig. 8

various possibilities for applying a paper web to a base body,

Fig. 9

differently concaved body with applied paper webs and

Fig. 10

differently movable printheads for printing on objects.

In FIG. 1 10 is a section of a paper web, for example a commercial paper sheet with predominantly wood cellulose fibers and a high white pigment content and an areal density of between about 50 and 90 g / m ² . The paper web 10 is simply calendered so that its fiber structure has an open porosity or absorbency toward the surfaces, as indicated schematically by the oblique parallel lines. It is understood that the pores or microchannels are drawn only schematically and are in fact also unaligned according to the disordered fiber structure of the paper web 10. In the left area of the FIG. 1 is the paper web 10 in the raw state, while it is soaked in the right-hand area on its underside 12 with a synthetic resin, for example a commercially available melamine resin, the first in a known manner is thin and cures, especially under heat. The amount of melamine resin 14 applied to the underside 12, its viscosity, basis weight, fiber type, fiber size and binder type (10), its thickness and porosity, and temperature are matched to one another such that the melamine resin 14 is the paper web 10 from the bottom 12 to the top 16 is not completely saturated or penetrated, but the adjacent to the top 16 area of the paper web 10 wholly or at least substantially free of melamine resin (indicated by black dots) remains and the absorbency of its raw state remains unchanged.

FIG. 2 shows an example of how the bottom 12 of the paper web 10 can be coated. A rotatable roller 18 is immersed in liquid melamine resin 14 received in a container 20. The paper web 10, from which optional later cuts are cut, is guided over the surface of the roll 18 wetted with melamine resin and thereby coated. The amount of melamine resin applied to the underside of the paper web 10 depends on the process parameters, such as viscosity of the melamine resin, immersion depth of the roll 18, surface finish of the roll 18, diameter of the roll 18, contact pressure between the paper web 10 and the roll 18, transport speed of the paper web etc.

FIG. 3 shows schematically how in the right section of FIG. 1 shown, melamine resin 14 coated on the underside paper web can be used to produce an article whose surface can be printed with a high-quality pattern. The FIG. 3 is divided from left to right into three sections a), b) and c).

The section a) shows a section of a base body 22, on which the paper web 10 is laminated by the melamine resin coated bottom 12 of the paper web 10 is pressed and heated to the top of the base body 20, so that the cured melamine resin 14 a secure adhesion between the base body 20, which is for example a press fiber body, and the paper web 10 causes. In the example shown, the base body 22 has a coating 24, for example made of synthetic resin, applied prior to the lamination of the paper web 10 in order to harden and temper its surface.

On the free top 16 of the paper web 10, which is not or hardly changed by the coating of the underside 12 with melamine resin, can, using conventional printing technology and data processing, for example, in an ink jet printing process, a pattern is printed in a high quality manner as indicated by the ink layer 26 (section b)), which is preferably partially absorbed by the paper web 10 prior to drying and thereby adheres very well to the paper web. The dyeing liquid and the porosity or surface of the paper web are matched to one another so that the color gradient corresponds to the desired pattern quality.

In section c) of FIG. 3 is the laminated with the paper web 10, printed with the ink layer 26 basic body 22 shown coated with an additional protective layer 28. This protective layer 28, which can be applied by a blasting or spraying process, a rolling process or otherwise, serves, for example, to protect the ink layer 26 from UV radiation and to protect it against mechanical damage. The protective layer 28, which may be transparent, is in a conventional manner a synthetic resin layer of very hard, resistant plastic, in which advantageously very hard particles are incorporated.

FIG. 4 The basic body 22, in the example shown in the form of a plate, is finished to the degree of the finished article to be produced and is provided with a cut of the paper 30 dimensioned according to the dimensions of the base body 22 completely laminated. The paper 30 may be soaked before being applied to the base body 22 at its the inner body 22 associated with inner side melamine resin and is then cured by application of pressure and heat and attached to the base body 22. Alternatively, a layer of still liquid melamine resin may be applied to the surface of the body 22 prior to application of the paper 30, dimensioned such that the melamine resin does not completely soak the paper as described FIG. 1 explained.

FIG. 5 shows a likewise plate-shaped base body 22 whose top and bottom are laminated or laminated with one paper sheet 30, wherein the paper sheets 30 each before or during application to the base body 22 with resin, as described FIG. 1 explained, partially soaked. On according to FIG. 5 Right front side of the main body 22, another appropriately cut paper sheet 30 can be applied directly. Alternatively, a marginal edge 32, which is rectangular or rounded in cross-section, may be glued or laminated onto the end face, onto which the paper sheet 30 is then applied. The Paper sheets 30 are either impregnated with resin prior to their application, or the surface to which the paper sheets are applied is coated with resin prior to their application, so that a penetration in accordance with FIG. 1 given is. It is understood that in the article according to FIG. 5 similar to in FIG. 4 a paper blank can be used, with which the main body including the peripheral edge (s) can be laminated as a whole.

The laminated with the paper body according to FIGS. 4 and 5 can then be printed in a conventional manner by an ink jet printing method or by any other method, and this results in an excellent pattern because of the present in the absorbent state paper surface. The printed article can then be coated with a protective layer 28 according to FIG. 3 be provided.

As can be seen from the above, the one-sided soaked paper layer has a dual function; On the one hand, the paper forms a lamination, hardening and, if necessary, quality improvement of the surface of the base body consisting of a low-cost material by the resin impregnation of its underside, and on the other hand, the non-resin-impregnated top side of the paper assumes the function of an adapter or primer for the printing process, in particular the inkjet Method.

The basic body, which may have any form suitable for lamination with paper, may consist of wood materials, plastics, fiber and / or particulate materials and also metallic materials. The thickness, density and further composition of the paper depends on the requirements of both the lamination and the printing process. As the paper compacting resin, any resin which cures especially under heat can be used. The application of the resin-impregnated paper can also be done after curing of the resin by the one-sided resinated paper layer is glued or otherwise laminated on the body.

• Fig. 6 zeigt eine Vorrichtung, mit der eine Papierbahn von beiden Seiten her mit Flüssigkeit beschichtet werden kann. Dazu weist die Vorrichtung zwei Flüssigkeitsaufbringeinrichtungen 34 und 36 auf, die in gegenseitigem Abstand angeordnet sind. Jede der Flüssigkeitsaufbringeinrichtungen enthält eine Aufbringwalze 38, die drehangetrieben ist und in Anlage an der Ober- bzw. Unterseite einer sich zwischen den Aufbringwalzen hindurchbewegenden Papierbahn 10 ist. Jede der Aufbringwalzen 38 ist in Anlage an einer Beschickungswalze 40, mit der auf den Außenumfang der Auftragswalze Flüssigkeit aus einem Vorratstank 42 aufgebracht wird.

In the following, modifications and developments of the invention described so far are explained:

• Fig. 6 shows a device with which a paper web can be coated from both sides with liquid. For this purpose, the device has two Flüssigkeitsaufbringeinrichtungen 34 and 36, which are arranged at a mutual distance. Each of the liquid applicators includes an applicator roll 38 which is rotationally driven and in abutment with the top and bottom surfaces, respectively, of a paper web 10 passing between the applicator rolls. Each of the application rollers 38 is in contact with a feed roller 40, with the liquid on the outer circumference of the applicator roll from a storage tank 42 is applied.

In the according to Fig. 6 lower storage tank is liquid resin 44. In the upper storage tank is water 46. The fibers of the paper web 10 are not aligned in the example shown, but could also be directed. The rotational speeds of the application rollers 38 are advantageously such that the paper web 10 transported between them is not stressed directly or in shear.

As shown, liquid resin 44 penetrates from the bottom into the paper web. From the top water 46 penetrates into the paper web. The paper web forms a capillary structure containing the liquid synthetic resin and. sucking in the water. The two liquids are not soluble in each other and therefore do not penetrate each other, so that the upper liquid forms in some way a barrier layer for the lower liquid and vice versa. The synthetic resin 44 thus does not penetrate to the top of the paper wall 10.

When the water 46 is subsequently evaporated ( Fig. 7 ), which evaporation can be assisted by a heater 48, the surface of the paper 10 is free of synthetic resin and unaltered for printing.

The water 42 fillers, dyes, pigments or corundum can be added so that an aqueous suspension is applied to the top of the paper web 10, the solids remain after evaporation of the top of the paper web and these, free of the resin 44, for a prepare the following, for example, inkjet printing optimally in accordance with the respective requirements.

As a barrier liquid and other liquids can be used which do not mix with the resin.

The at least largely resin-free upper side or the at least largely resin-free upper region of the paper web 10 according to the right half of Fig. 1 or the Fig. 7 in which the fibers of the paper web are exposed more or less aligned depending on the structure and structure of the paper, an anchoring layer is formed on the one hand in a subsequent step, from above into the paper web penetrating lamination and also an anchoring layer for a paint, which is applied to the top of the paper layer and penetrates into this. The anchoring layer is therefore particularly stable because, as out Fig. 1 and Fig. 7 can be seen, paper fibers protrude into the resin 14 and 44 and are stabilized after its drying in position and optionally additionally stabilized along its length by small amounts of the dried resin.

The resin 44 may be different depending on the requirements. When the paper web 10 is placed on a base body 22 (FIG. Fig. 5 ) should be laminated with a flat surface, for example by pressing and interposition of an adhesive layer, the resin may be thermosetting, ie after curing by heating no longer be liquefied or softened. If the paper web has to be bent when applied to the base body, the synthetic resin is advantageously thermoplastic, so that it softens when the paper web is laminated onto the surface of a base body under heating. If the surface of the main body 22 is such that the paper web must be stretched to conform to three-dimensional surface structures, the paper web is stretchable, for example, having a structure with unoriented fibers that are changed in orientation or in length can.

Another possibility of applying the paper web to a base body is that the surface of the base body is coated with a cured state on her adhesive resin and the paper web is rolled onto the resin-coated base body, wherein the paper web on the body under pressure pressing roller 38 of the liquid applicator 34 (FIG. Fig. 6 ) can be. In this way, this is based on the FIGS. 6 and 7 described method carried out simultaneously with the application of the paper web to the body.

It should be noted that in particular in plate-shaped bodies, on top of which a paper web is laminated on the underside of an acting as a tie rod layer laminated, for example, is glued, so that the finished object as a result of the paper layer ago, for example, in their printing or whose further surface treatment (application of a protective varnish) does not distort the resulting stresses.

The printing of the paper layer can be carried out prior to its application to a base body or after its application to a base body. Likewise, a protective layer can be applied to the printing layer even before the application of the paper web to the base body or only after the application.

Fig. 8 illustrates in the figure parts A, B, C three different ways in which a inventively impregnated according to the invention from one side impregnated with synthetic resin paper web can be applied to a base body, wherein the application can be carried out by rolling, in a mold and / or by a vacuum method.

According to Fig. 8A For example, a paper web 10 ₁ impregnated with synthetic resin and optionally already printed on is provided with a further resin or adhesive layer 50 and applied to the base body 22. The adhesive layer 50 imparts adhesion between the base body and the resin-impregnated underside of the paper web.

According to Fig. 8B is the underside of the paper web 10 _{2 provided} with a partially penetrated into the paper web 10 ₂ resin layer 52, which also takes over the adhesion when pressing the paper web 10 ₂ on the base body 22.

According to Fig. 8C An adhesive layer 54 is applied to the base body 22, to which subsequently the ready-prepared paper web 10 is applied.

In the method according to FIGS. 8A and C Thus, with respect to the application of the adhesive or synthetic resin layer are two-stage process, while the method according to Fig. 8B is single-stage.

Fig. 9 shows various types of bodies 22, on the already printed or not printed and prepared only for printing paper webs 10 are applied.

The main body 22 according to Fig. 9A has a flat top on which the paper web 10 is applied. The paper web 10 may thus be stiff in itself.

In the embodiments according to Fig. 9B For example, the paper web 10 is subjected to bending at least when it is applied, so that it has to allow a partially penetrating synthetic resin to bend the paper web. In the uppermost embodiment of Fig. 9B two base body 22 are connected via the paper web 10, so that the paper web 10 optionally forms a film hinge, for which it is suitable by appropriate consistency of the resin.

The main body 22 according to Fig. 9C has a three-dimensional curved surface (its contour is in from Fig. 9C different cutting planes different). For this purpose, the laminated to the top of the body 22 paper web 10 ₁ at least during their application by appropriate consistency of the base paper stretchable and the resin impregnation correspondingly soft, so that the partially impregnated with the resin paper web during lamination without wrinkles or even cracking on the surface of the base body 22 adapts. The paper web 10 ₂ applied to the right-hand side surface according to the figure may be different from the paper web 10. Both paper webs can also be integrally formed with each other. However, it is advantageous to apply the paper web 10, and 10 ₂ separately from one another, for example by first laminating the paper web 10, onto the three-dimensional surface of the main body 22, pressing it or otherwise applying it in a soft-forming process, and then the edge of the paper web 10 _{1 is separated} by means of a running in the plane r cut. The cut can be indicated in the press mold or on the main body, so that it is subsequently carried out cleanly and the paper web 10 ₂ applied to the side surfaces of the main body 22 adjoins cleanly the paper web 10 ₁ . In this way it is avoided that the three-dimensional application of the paper web 10, forming at protruding areas distortions are avoided.

Fig. 10 shows in the different representations different ways how a laminated with a paper web 10 base body 22 can be inkjet printed using a printhead.

According to a), the flat upper side of the article is printed with a print head 56 which is movable in a horizontal plane. According to b), the vertical side surface of the article is printed with a print head 58, which is movable in a vertical plane. An article having a horizontal and vertical surface according to c) is printed with both printheads 56 and 58.

For example, an article that has soft edges with large radii may be imprinted with the printhead 56 on its flat top surface. The side surface including the curved edge regions are printed with a print head 60 which is pivotally and vertically movable about an axis perpendicular to the drawing paper plane.

In the embodiment according to Fig. 4e ), the print head 62 is pivotable about an axis perpendicular to the drawing paper plane and movable in the horizontal and vertical directions.

In the embodiment according to Fig. 4f ) in which the surface of the object to be printed is curved three-dimensionally, a print head 64 is used, which is pivotable by means of a robot about two mutually perpendicular axes and in the horizontal and vertical. If the surface of the object according to f) has curved areas only around axes perpendicular to the plane of the drawing, the print head 62 according to e) can be used.

LIST OF REFERENCE NUMBERS

10

paper web

12

bottom

14

melamine resin

16

top

18

roller

20

container

22

body

24

coating

26

coat of paint

28

protective layer

30

paper

32

edge

34

liquid application

36

liquid application

38

applicator

40

feed roller

42

storage tank

44

resin

46

water

48

heater

50

adhesive layer

52

resin layer

54

adhesive layer

56

printhead

58

printhead

60

printhead

62

printhead

64

printhead

Claims (12)

1. Method for manufacturing a surface printable in particular by means of an ink jet printing method, in which method a paper sheet (10) absorbent for liquid resin over its entire thickness is impregnated on one side with the liquid resin such that the liquid resin does not completely penetrate the paper sheet, so that the other side (16) of the paper sheet remains at least substantially free of resin.
2. Method according to claim 1, wherein the quantity and/or the viscosity and/or the capillarity and/or the temperature of the liquid resin (14; 44) is controlled such that it does not completely penetrate the paper sheet (10).
3. Method according to claim 1, wherein the paper sheet (10) is impregnated on one side with liquid resin (44) and on the other side with a barrier fluid (46) permeating therein, which barrier fluid (46) forms a barrier layer for the liquid resin in the paper sheet and is evaporated after curing the resin.
4. Method according to claim 3, wherein the barrier fluid (46) comprises at least one solid material that remains in the paper sheet when evaporating.
5. Method according to one of claims 1 to 4, wherein the resin (14; 44) is thermoplastic.
6. Method according to one of claims 1 to 5, wherein the liquid resin permeating into the paper sheet (10) on one side thereof is applied onto a base body, onto which base body the paper sheet is applied.
7. Method according to one of claims 1 to 5, wherein the paper sheet (10), which is not completely penetrated by resin, is applied onto a base body (22).
8. Method according to claim 7, wherein an adhesive (54) is applied onto the base body (22) before applying the paper sheet.
9. Paper sheet having a surface printable in particular by means of an ink jet printing method, which paper sheet (10) is absorbent for resin on its printable surface (16) and is impregnated with resin on its side facing away from the printable surface, wherein the resin (14; 44) does not completely penetrate the paper sheet, so that the printable surface is at least substantially free of resin.
10. Paper sheet according to claim 9, which paper sheet (10) includes a stretchable structure.
11. Printable object that is laminated at least partially with a paper sheet according to claim 9 or 10.
12. Device for applying liquids onto a paper sheet comprising
    two application rollers (38) disposed in opposing separation, between which the paper sheet (10) is transported therethrough, wherein the application rollers are each coated with liquids (44, 46) by a liquid supply (34, 36; 40),
    characterised in that
    the one reservoir tank (42) contains a resin (44) and the other reservoir tank (42) contains a barrier fluid (46), wherein the barrier fluid is such that it forms a barrier layer for the liquid resin, so that the resin does not completely penetrate the paper sheet, and it is vaporizable by heating after curing the resin.

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