METHOD FOR PRODUCING COATED PAPER WITH PEARLESCENT EFFECT

Description

Technical Field

[0001] The present invention relates to a method for producing coated paper with pearlescent effect.

Background Art

[0002] Currently, coated papers are increasingly important in the graphic sector.

[0003] In particular, so-called ivory or embossed coated papers are rather widespread and are produced by combining the traditional processes for producing coated papers with the methods for obtaining the so-called ivory or embossed effect.

[0004] However, currently it is not easy to obtain a coated paper with pearlescent effect by using conventional processes.

[0005] The pearlescent effect, according to current knowledge, can in fact be obtained either by depositing, by means of a stiff blade, the pearlescent pigments on the paper medium on which the coating has been spread beforehand, or by mixing the pearlescent pigments with the coating and then spreading the resulting mixture onto the paper medium.

[0006] However, it has been found that the products obtained with the methods described above are very poor.

[0007] The dimensions of the pearlescent pigments are in fact distinctly larger (by approximately ten times) than those of conventional coatings, and it is therefore practically impossible to obtain a uniform mixture.

[0008] Furthermore, in order to allow pearlescent pigments to express their characteristic effect, they must remain completely on the surface, whereas if they are mixed with the coating they also distribute proximate to the paper medium.

[0009] Finally, it should be noted that if the pearlescent pigments are deposited by means of a stiff blade, since they are, as mentioned, considerably larger than the pigments that constitute the coating, they form streaks and/or lines.

[0010] Documents US 4409280, WO95/06568 and US 5571557 describe, respectively, decorative surface coverings, processes for achieving decorative laminates and a transfer product designed to look like etched glass surface.

Disclosure of the Invention

[0011] The aim of the present invention is to provide a method for producing coated paper with pearlescent effect that is capable of eliminating or in any case drastically reducing the drawbacks noted above of conventional methods.

[0012] Within this aim, an object of the invention is to provide a method for producing coated paper with pearlescent effect that allows to obtain a paper with high printability.

[0013] Another object of the present invention is to provide a technological solution that allows to provide a range of coated papers with pearlescent (or slightly pearlescent) effect while maintaining a high brightness, so as to allow their use in the most disparate sectors, from graphics to packaging and covering to advertising.

[0014] Another object of the invention is to provide a method for producing coated paper with pearlescent effect that allows to obtain coated papers with pearlescent effect on one or both sides of the paper medium.

[0015] This aim and these and other objects that will become better apparent hereinafter are achieved by a method according to the invention, that comprises the steps set forth in claim 1.

[0016] Advantageously the coating with pearlescent effect comprises at least nitrocellulose resins, mica-based pigments, and a solvent.

[0017] According to another aspect, the present invention provides a coated paper with pearlescent effect, that has the features set forth in claim 8.

Brief Description of the Drawings

[0018] Further aspects and advantages of the invention will become better apparent from the present detailed description of some currently preferred examples of embodiments, given merely by way of non-limiting example with reference to the accompanying drawings, wherein:

Figure 1 is a perspective view of a coated paper with pearlescent effect according to the invention;

Figure 2 is a perspective view of a deposition cylinder;

Figure 3 is an enlarged-scale side elevation view of the outer surface of the deposition cylinder shown in Figure 2; and

Figure 4 is a sectional view, taken along the line IV-IV of Figure 3.

Ways of carrying out the Invention

[0019] In the examples of embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other examples of embodiments.

[0020] Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.

[0021] As shown by the figures, the present invention relates to a method for producing coated paper having a pearlescent effect, generally designated by the reference numeral 1,

[0022] In particular, the production process according to the invention provides that at least one deposition of at least one layer 3 a of coating is performed at at least one side 2a of a paper medium 2, first of all, by way of per se known devices or systems.

[0023] Also according to the invention, the method for producing coated paper with pearlescent effect provides for an additional deposition of a pearlescent coating 3b over the coating layer 3a.

[0024] In particular, the additional deposition of pearlescent coating 3b is performed by using rotogravure (or flexographic) devices (or systems), constituted by a deposition roller 4, which has a plurality of deposition cells 5 at its outer side wall 4a.

[0025] In greater detail, a method for producing coated paper having a pearlescent effect, merely by way of example, can provide for a first deposition of a layer of conventional coating approximately 6-12 µm thick on both sides (2a and 2b) of a paper medium 2 that has a thickness of approximately 100 µm.

[0026] Then, according to a preferred embodiment, an additional layer of coating of approximately 1-8 µm per side is deposited on both sides.

[0027] It is evident that after these depositions (of "conventional" coating), the thickness of the medium will be approximately 116-140 µm.

[0028] According to the invention, a layer of pearlescent coating is then applied on one or both sides of the resulting medium by way of a system or device of the rotogravure/flexographic type, constituted by a deposition roller 4.

[0029] By way of example, this deposition or these depositions of layers of pearlescent coating is(are) performed by placing the medium, or rather both faces of the medium, in contact with the outer side wall of the deposition roller 4.

[0030] The coating layer(s) containing the pearlescent pigments deposited by the deposition roller 4 has(have) a thickness of approximately 2-6 µm, which accordingly brings the total thickness of the resulting paper to 120-152 µm.

[0031] Naturally, nothing forbids the use of initial paper media of different thickness, or the deposition of thicknesses of coating (or pearlescent coating) having thicknesses that differ from those indicated in the method described above, as long as these thicknesses are within the ranges as required by claims 1 and 8.

[0032] Advantageously, the pearlescent coating comprises at least nitrocellulose resins, mica-based pigments, and a suitable solvent.

[0033] According to another aspect, the present invention provides a coated paper with pearlescent effect 1, which is constituted by a paper medium 2 that has, at at least one side 2a, at least one coating layer 3a and, above the coating layer 3a, at least one coating layer 3b with pearlescent effect.

[0034] All the characteristics of the invention described above as being advantageous, convenient or the like may also be omitted or replaced with equivalents.

[0035] All the details may further be replaced with other technically equivalent elements.

[0036] The materials and the dimensions may be various according to requirements.

Claims

1. A method for producing a high brightness, high printability coated paper with pearlescent effect, comprising the steps of:

-- providing a paper medium having a thickness comprised between 70 and 400 µm;

-- performing a first deposition, on at least one side of the paper medium, of at least one layer of coating;

-- performing a second deposition of a pearlescent coating, over said at least one layer of coating, by means of a rotogravure or flexographic device that comprises at least one deposition roller that has an outer deposition wall provided with a plurality of deposition cells so as to provide a surface coating layer comprising pearlescent pigments which has a thickness comprised between 2-6 µm.

2. The method for producing coated paper with pearlescent effect according to claim 1, characterized in that said coating with pearlescent effect comprises at least nitrocellulose resins, mica-based pigments, and a solvent.

3. The method for producing coated paper with pearlescent effect according to claims 1 comprising providing said at least one deposition roller with said plurality of deposition cells located at its outer deposition side wall.

4. The method for producing coated paper with pearlescent effect according to claim 1, characterized in that said first deposition step comprises deposition of a first and second layers of coating, said first layer of coating having a thickness comprised between 6 and 12 µm, and said second layer of coating having a thickness comprised between 1 and 8 µm.

5. The method for producing coated paper with pearlescent effect according to claim 4, characterized in that said deposition of said first and second layers of coating is performed at both sides of said paper medium.

6. The method for producing coated paper with pearlescent effect according to claim 1, characterized in that said additional deposition of a coating with pearlescent effect is performed over both of said first deposition layers.

7. The method for producing coated paper with pearlescent effect according to claims 1 or 6, characterized in that said additional deposition of a coating with pearlescent effect has a thickness comprised between 2 and 6 µm per side.

8. A high brightness, high printability coated paper with pearlescent effect, characterized in that it comprises a paper medium (2) having a thickness between 70 and 400 µm that has, at at least one side thereof, at least one layer of coating (3a) and, above said at least one layer of coating (3a), at least one surface layer of coating (3b) comprising pearlescent pigments and which has a thickness comprised between 2-6 µm.

Ansprüche

1. Verfahren zur Herstellung von beschichtetem Papier von hoher Helligkeit und hoher Bedruckbarkeit mit Perlglanzeffekt, umfassend die folgenden Schritte:

-- Bereitstellen eines Papiermediums mit einer Dicke zwischen 70 und 400 µm;

-- Durchführen einer ersten Auftragung wenigstens einer Beschichtungsschicht auf wenigstens einer Seite des Papiermediums;

-- Durchführen einer zweiten Auftragung einer Perlglanzbeschichtung über der wenigstens einen Beschichtungsschicht mittels einer Rotationstiefdruck- oder Flexodruckvorrichtung, die wenigstens eine Auftragswalze umfasst, welche eine mit einer Vielzahl von Auftragszellen versehene äußere Auftragswand aufweist, um eine perlglanzpigmenthaltige Deckbeschichtungsschicht zu bilden, die eine Dicke zwischen 2 und 6 µm aufweist.

2. Verfahren zur Herstellung von beschichtetem Papier mit Perlglanzeffekt nach Anspruch 1, dadurch gekennzeichnet, dass die Beschichtung mit Perlglanzeffekt wenigstens Nitrocelluloseharze, Pigmente auf Glimmerbasis und ein Lösungsmittel umfasst.

3. Verfahren zur Herstellung von beschichtetem Papier mit Periglanzeffekt nach Anspruch 1, umfassend die Bereitstellung der wenigstens einen Auftragswalze mit der Vielzahl von Auftragszellen, die sich an ihrer äußeren Auftragsseitenwand befinden.

4. Verfahren zur Herstellung von beschichtetem Papier mit Perlglanzeffekt nach Anspruch 1, dadurch gekennzeichnet, dass der erste Auftragsschritt das Auftragen einer ersten und einer zweiten Beschichtungsschicht umfasst, wobei die erste Beschichtungsschicht eine Dicke zwischen 6 und 12 µm aufweist und die zweite Beschichtungsschicht eine Dicke zwischen 1 und 8 µm aufweist.

5. Verfahren zur Herstellung von beschichtetem Papier mit Periglanzeffekt nach Anspruch 4, dadurch gekennzeichnet, dass die Auftragung der ersten und der zweiten Beschichtungsschicht auf beiden Seiten des Papiermediums erfolgt.

6. Verfahren zur Herstellung von beschichtetem Papier mit Periglanzeffekt nach Anspruch 1, dadurch gekennzeichnet, dass die zusätzliche Auftragung einer Beschichtung mit Perlglanzeffekt über beiden ersten Auftragsschichten erfolgt.

7. Verfahren zur Herstellung von beschichtetem Papier mit Periglanzeffekt nach Anspruch 1 oder 6, dadurch gekennzeichnet, dass die zusätzliche Auftragung einer Beschichtung mit Periglanzeffekt pro Seite eine Dicke zwischen 2 und 6 µm aufweist.

8. Beschichtetes Papier von hoher Helligkeit und hoher Bedruckbarkeit mit Perlglanzeffekt, dadurch gekennzeichnet, dass es ein Papiermedium (2) mit einer Dicke zwischen 70 und 400 µm umfasst, das auf wenigstens einer seiner Seiten wenigstens eine Beschichtungsschicht (3a) und über der wenigstens einen Beschichtungsschicht (3a) wenigstens eine Deckbeschichtungsschicht (3b) aufweist, die Perlglanzpigmente enthält und die eine Dicke zwischen 2 und 6 µm aufweist.

Revendications

1. Procédé de production d'un papier couché de haute blancheur et haute imprimabilité avec effet perlé, comprenant les étapes consistant à :

- fournir un support papier ayant une épaisseur comprise entre 70 et 400 µm ;

- effectuer un premier dépôt, sur au moins un côté du support papier, d'au moins une couche de revêtement ;

- effectuer un second dépôt d'un revêtement perlé, sur ladite au moins une couche de revêtement, au moyen d'un dispositif de rotogravure ou d'un dispositif flexographique qui comprend au moins un rouleau de dépôt, qui comporte une paroi de dépôt externe pourvue d'une pluralité de cellules de dépôt de façon à former une couche de revêtement de surface comprenant des pigments perlés qui a une épaisseur comprise entre 2 et 6 µm.

2. Procédé de production d'un papier couché avec effet perlé selon la revendication 1, caractérisé en ce que ledit revêtement avec effet perlé comprend au moins des résines de nitrocellulose, des pigments à base de mica et un solvant.

3. Procédé de production d'un papier couché avec effet perlé selon la revendication 1, comprenant la fourniture d'au moins un rouleau de dépôt avec ladite pluralité de cellules de dépôt située sur sa paroi latérale de dépôt externe.

4. Procédé de production d'un papier couché avec effet perlé selon la revendication 1, caractérisé en ce que ladite première étape de dépôt comprend le dépôt d'une première et d'une seconde couche de revêtement, ladite première couche de revêtement ayant une épaisseur comprise entre 6 et 12 µm, et ladite seconde couche de revêtement ayant une épaisseur comprise entre 1 et 8 µm.

5. Procédé de production d'un papier couché avec effet perlé selon la revendication 4, caractérisé en ce que ledit dépôt desdites première et seconde couches de revêtement est effectué des deux côtés dudit support papier.

6. Procédé de production d'un papier couché avec effet perlé selon la revendication 1, caractérisé en ce que ledit dépôt additionnel d'un revêtement avec effet perlé est effectué sur les deux dites premières couches de dépôt.

7. Procédé de production d'un papier couché avec effet perlé selon la revendication 1 ou 6, caractérisé en ce que ledit dépôt additionnel d'un revêtement avec effet perlé a une épaisseur comprise entre 2 et 6 µm par côté.

8. Papier couché de haute blancheur et haute imprimabilité avec effet perlé, caractérisé en ce qu'il comprend un support papier (2) ayant une épaisseur comprise entre 70 et 400 µm qui a, sur au moins l'un de ses côtés, au moins une couche de revêtement (3a) et, au-dessus de ladite au moins une couche de revêtement (3a), au moins une couche de surface de revêtement (3b) comprenant des pigments perlés et qui a une épaisseur comprise entre 2 et 6 µm.

Drawing