EP2516741A1

EP2516741A1 - Ultrasmooth and recyclable printable sheet and process for manufacturing same

Info

Publication number: EP2516741A1
Application number: EP10809308A
Authority: EP
Inventors: Gaël DEPRES; Jean-Marie Vau
Original assignee: Arjo Wiggins Fine Papers Ltd
Current assignee: AW Branding Ltd
Priority date: 2009-12-23
Filing date: 2010-12-22
Publication date: 2012-10-31
Anticipated expiration: 2030-12-22
Also published as: FR2954361B1; ES2517365T3; RU2012122864A; US20120308744A1; US9416495B2; EP2516741B2; BR112012015134A2; ES2517365T5; CN102666989B; HK1173478A1; JP2016106183A; EP2516741B1; JP2013515628A; WO2011077048A1; RU2538581C2; CN102666989A; FR2954361A1; KR20120125406A; KR101970770B1; CA2785183C

Abstract

Process for manufacturing a smooth, or even ultrasmooth, printable sheet comprising the steps consisting in: preparing a multilayer structure (12) comprising at least one lower plastic film (14), a non-stick intermediate layer (16), and a printable upper layer (18), sizing one face (30) of a substrate (24) or the upper face (28) of the printable layer, and applying the substrate to the printable layer, in order to laminate them, then removing the plastic film from the printable layer, this printable layer (18) defining, on the sheet, a smooth or ultrasmooth face (22).

Description

Ultra-smooth and recyclable printable sheet

and its manufacturing process

The present invention relates to a printable sheet smooth or ultra smooth and recyclable, as well as its manufacturing process. This sheet may be used in distinct fields such as packaging, electronics, optics, or graphic arts, for example as a printing medium, in particular a photographic image.

In the known art, an ultra-smooth sheet may be made by laminating a plastic film on one side of a paper, which plastic film defines an ultra smooth surface on the paper. The base paper is formed of a fibrous material whose faces have a relatively high roughness, of the order of 20μηη approximately, that is to say that each of its faces is formed of bumps and valleys whose height which separates them is of the order of 20μηη. The rolling of a plastic film on one side of such a paper makes it possible to give this face a very low roughness, of the order of 1 μηη in the case of a film of PET (polyethylene terephthalate).

Because paper is a relatively expensive material and is produced on a large scale, it is important that it be recyclable. However, a paper-based sheet, ultra smooth because having a plastic film is not recyclable or is difficult to recycle, which is not ecological or economic. Indeed, during the recycling of paper-based sheets, these sheets are crushed and mixed with water in a pulper to form a paste. In the case where these sheets comprise plastic films, these films are shredded in the pulper and their plastic material pollutes the paste.

It is therefore not possible, with the current technique, to make an ultra smooth sheet that is recyclable, preferably fully recyclable.

Moreover, such an ultra smooth sheet is not printable and a printable resin must be deposited on the plastic film of the sheet for make printable. This technique is used in particular to produce paper-based sheets for the printing of photographic images (called resin-coated photography papers), these sheets comprising a PE film (polyethylene) and having a Bekk smoothness of the order 6000s.

A smooth sheet may also be manufactured by depositing a coating composition on one side of a paper, which composition after drying a smooth face on the paper. This technique makes it possible to manufacture a smooth sheet without plastic film. The composition is deposited on the paper by a coating technique curtain, dragging or scraping blade, air knife, gravure printing or by rollers (s / ^' ze press, press film, etc.). The face of the paper base, on which the coating composition is deposited, comprises an alternation of hollows and bumps, the hollows being filled by the coating composition and the bumps being flattened during coating, which makes it possible to reduce the roughness of the paper. However, this technique does not make it possible to obtain a sheet as smooth as a sheet covered with a plastic film, even if this sheet is subsequently smoothed, for example by calendering.

The method currently used to make a glossy, smooth sheet consists in depositing a coating composition on a base paper by means of a mechanical roller whose cylindrical surface is very smooth and covered with a layer of chromium. The Bekk smoothness of a sheet obtained by this process is of the order of 50s and is therefore less than that of a sheet comprising a plastic film (of the order of 6000s in the case of a PE film) .

Furthermore, it is difficult to obtain a smooth sheet by coating a composition on a relatively rough paper. Indeed, when the aforementioned hollows of the face of the paper are too large or too many, the coating composition does not fully fill these hollows, or too much of this composition is necessary to do so. This is for example the case of a paper having a relatively large hand, for example greater than 1, 10cm ³ / g, which therefore has relatively rough faces and low printability. The coating of a composition on one side of this paper, even in large quantities, does not make it possible to manufacture a smooth sheet, and considerably reduces its hand considerably. Moreover, even if the calendering of the sheet allowed to increase its smoothness, it would be done to the detriment of his hand.

It is therefore also not possible, with the known technique, to manufacture under satisfactory conditions, a smooth sheet from a rough paper and / or having a relatively large hand.

The invention is particularly intended to provide a simple, effective and economical solution to the problems of the prior art.

It relates to a method of manufacturing a smooth sheet, also called ultra smooth in the sense of the invention, the smoothness of this sheet being independent of the roughness of the paper or more generally of the base substrate used, and the sheet does not having no plastic film and is therefore at least partly recyclable, or even biodegradable.

To this end, it proposes a method of manufacturing a printable sheet having at least one smooth face, and advantageously ultra smooth, this sheet comprising a substrate, in particular of paper, of which at least one face is covered at least in part with one or more superimposed layers, the method comprising the steps of:

a / preparing or providing a multilayer structure comprising at least, or consisting of, a preferably smooth plastic film, a release layer, and a printable layer, the release layer being interposed between the plastic film and the printable layer,

b / bonding a face of the substrate and / or the face of the multilayer structure, located on the opposite side to the plastic film, and applying the aforementioned face of the substrate against the aforementioned face of the multilayer structure, so as to laminate the multilayer structure and the substrate, and cl remove the plastic film from the printable layer, this printable layer defining said smooth or ultra smooth face of the sheet.

In a particular embodiment of the invention, the multilayer structure is prepared prior to the implementation of the method of manufacturing the printable sheet. In this case, the multilayer structure is provided for the production process of the printable sheet.

According to the invention, the smooth or ultra-smooth face of the sheet is defined by a printable layer which is prepared on a plastic film called "donor", said printable layer being, at this stage, included in a multilayer structure, and then transferred on the basic substrate called "receiver". The smoothness of the printable layer and therefore of the sheet is induced by that of the plastic film of the multilayer structure, and therefore does not depend on that of the base substrate used. The invention thus makes it possible to transfer the surface state of a plastic film to any substrate. In other words, the invention makes it possible to manufacture a smooth or ultra-smooth sheet from any substrate, such as advantageously a rough paper and / or having a relatively large hand, for example greater than or equal to 1.10 cm ³ / g, and without including a plastic film in the sheet thus produced.

The sheet prepared by the process according to the invention is therefore both printable and recyclable.

In this application, printable sheet and substrate for the preparation of the printable sheet, a thin element (whose thickness does not exceed 50Όμηη), preferably flexible and / or flexible.

Printable sheet or layer means a sheet or layer that can be printed by any printing technique, and in particular by printing Offset, inkjet, laser, helio, flex, dry toner, liquid toner, electrophotography, lithography etc. A printable layer typically comprises a mixture of pigments and at least one binder, or is formed of a printable varnish based on polymer (s) of acrylic, vinyl, polyurethane, styrene, starch, polyvinyl alcohol, ethylene, or a mixture of these polymers. The ink is intended to be deposited on the smooth or ultra smooth free face of the printable sheet or the printable layer. Recyclable sheet means a sheet which is free of plastic film, for example thermoplastic or thermosetting material.

According to one characteristic of the invention, the printing of the printable layer does not entail any structural modification thereof, and in particular a change of state or phase thereof (such as for example from a solid state to a liquid state and then back to the solid state).

A multilayer structure of the invention prepared or provided in the context of the process according to the invention comprises, in particular, or consists of, a lower plastic film, a nonstick intermediate layer and a printable top layer. The release layer covers at least a portion of the top face of the plastic film, and the printable layer covers at least a portion of the top face of the release layer.

The plastic film serves as a manufacturing support for the printable layer. This film does not survive in the final product, namely the sheet, which is therefore recyclable. The upper face of the film (located on the side of the printable layer) is advantageously the smoothest possible, because the surface quality of the smooth face of the sheet, defined by the printable layer, is a function of the surface quality of this face top of the plastic film. In other words, the more the plastic film of the multilayer structure is smooth and the resulting sheet is smooth.

The plastic film is selected from a film of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polylactic acid-based polymer (PLA), any cellulose-based polymer, and the like. The film has for example a thickness of the order of 12μηη. Advantageously, the plastic film is free and / or is not covered with PVDF (polyvinylidene fluoride), PP (polypropylene), teflon, silica, boron nitride, chromium stearyl chlorides or any other product having anti-adhesive / non-stick properties.

The face of the film located on the printable layer side is preferably smooth and may have a Bekk smoothness greater than 10,000s Bekk.

The thickness, hardness and glass transition temperature of the plastic film have no or little influence on the characteristics of the printable layer. Only the smoothness, or conversely, the roughness of the plastic film has an influence on the smoothness or roughness of the printable layer. The smoother the plastic film, the smoother the printable layer. Those skilled in the art are however able to determine which characteristics of the plastic film are likely to influence the surface condition of the printable layer, and to optimize these characteristics as a function of the final smoothness that is desired for this printable layer.

The nonstick layer of the multilayer structure is deposited on the plastic film by any technique, for example by gravure printing. This non-stick layer serves to limit the adhesion of the printable layer on the plastic film and to facilitate the separation and removal of the plastic film from the printable layer in step c / of the above-defined process. The nonstick layer does not affect or reduce the smoothness and the surface quality of the plastic film face on which this layer is deposited.

The nonstick layer may adhere more to the plastic film than to the printable layer, so that most or all of the nonstick layer remains adhered to the plastic film as it is removed from the printable layer. However, parts or traces of this release layer may persist on the printable layer after removal of the plastic film. Alternatively, the release layer may adhere more on the printable layer than on the plastic film, and is then intended to remain at least partially on the printable layer during removal of the plastic film.

In yet another variant, the release layer is intended to divide substantially into two parts upon removal of the plastic film, a first portion remaining on the plastic film and a second portion remaining on the printable layer.

The multilayer structure may comprise two non-stick layers superimposed between the plastic film and the printable layer, these two layers being intended to separate from one another during the removal of the plastic film (one of the non-stick layers remaining on the plastic film and the other non-stick layer remaining on the printable layer).

Leaving part or all of a nonstick layer on the printable layer is particularly advantageous when the sheet is intended to be used as a support in a casting application. The casting application consists of extruding and casting at least one polymer (such as polyurethane (PU), polyvinyl chloride (PVC), etc.) onto a support coated with a release layer. This polymer may have a textured surface to give the sheet a particular appearance (eg, similar to leather). The fact of leaving a release layer on the sheet according to the invention avoids having to redeposit such a layer on this sheet for a casting application, and is therefore particularly advantageous in terms of cost and preparation time of the support for the application. casting application.

The release layer has a thickness less than or equal to 5μηη and preferably 1 μηη. The release layer may be composed of silicone (s), siloxane (s), polysiloxane (s) or its derivatives, Werner complex (s), such as chromium stearyl chlorides, or polyethylene waxes, propylene, polyurethane, polyamide, polytetrafluoroethylene, etc. Advantageously, the nonstick layer comprises no

PVDF.

The printable layer of the multilayer structure may be selected from a printable varnish, a paper coating, etc.

In the present application, the term "printable varnish" means a substance based on acrylic polymer, polyurethane, polymethyl methacrylate, styrene butadiene, vinyl acetate, polyamide, nitrocellulose or any other cellulose, polyvinyl alcohol, polyvinyl alcohol, polyvinyl alcohol, starch, etc. This substance is usually deposited in liquid form and solidified by drying / heating or by UV or electron radiation.

The term "paper coating" or coating composition means a composition comprising a binder and pigments. The binder may be based on acrylic, polyurethane, polymethyl methacrylate, styrene butadiene, vinyl acetate, polyamide, nitrocellulose or any other cellulose, polyvinyl alcohol, starch, or a mixture of these. this. The pigments may be chosen from calcium carbonates, kaolins, titanium dioxide, talc, silicas, mica, and pearlescent particles, plastic pigments (polystyrene (PS), polyurethane (PU), etc.), and their mixtures. The level of binder relative to the pigments is between 5 and 50%, and preferably between 8 and 25% by dry weight. Pigments are generally in the majority of the binder in a paper coating, to create porosities that improve ink absorption. On the contrary, in a heat transfer layer, the binders are in the majority with respect to the pigments because the objective is not to have surface porosity.

The plastic used in the printable layer (as a binder and / or pigments) is easily fragmentable and does not pollute the pulp when recycled. On the contrary, the plastic films keep a cohesion and clog the filters during the resuspension of the pulp. Water-soluble binders (such as starch, polyvinyl alcohol (PVA), etc.) are particularly advantageous in this regard because they disperse in water during recycling.

The paper coating may further comprise a dispersant and / or a rheological modifier and / or a colorant and / or a surface or spreading agent and / or a conductive additive. This conductive additive can be used to reduce the surface resistivity of the sheet.

Preferably, the printable layer is free of antiblocking agent and / or of product capable of reducing the surface energy of the layer, such as a silicone material or the like, PVDF, PP, Teflon, silica , boron nitride, etc. This type of agent or product may be required for thermal transfer layer printing, particularly to prevent paper from adhering to the printer ribbon. The printable layer according to the invention may therefore not be printable by thermal transfer.

The printable layer may be formed of several sub-layers superimposed on each other, each sub-layer being printable and being selected from the aforementioned types (printable varnish, paper coating, etc.).

The printable layer may have a thickness less than or equal to 30μηη, preferably less than or equal to 15μηη, and more preferably less than or equal to 10μηη. Its grammage is advantageously less than or equal to 30 g / m ² , preferably less than or equal to 15 g / m ² , and more preferably less than or equal to 10 g / m ² . The printable layer may for example have a thickness and a grammage that are less than or equal to the following combined values: 10μηη and 10g / m ² , 3μηη and 10g / m ² , 2μηη and 10g / m ² , 5μηη and 5g / m ² , 3μηη and 5g / m ² , 2μηη and 5g / m ² , 5μηη and 2g / m ² , 3μηη and 2g / m ² , or 2μηη and 2g / m ² .

The printable layer can be deposited on the release layer by any technique, for example by gravure printing.

The printable layer may be deposited on the nonstick layer in the liquid or semi-liquid state and then be solidified by drying, heating, or by UV or electronic radiation. After solidification and / or drying, the printable layer, which is in contact with the smooth side of the plastic film via the release layer, has a smooth face, located on the side of the plastic film.

The printable layer is thus dried and / or solidified before it is transferred onto the substrate, in particular so as not to modify the surface state of this layer conferred by the plastic film. In other words, the multilayer structure is prepared prior to the transfer of the printable layer on the substrate, and the printable layer is in the solid state and / or dry during its transfer on the substrate, that is to say in steps b and cl of the process according to the invention. The surface state of the printable layer is thus created during the preparation of the multilayer structure.

In the process according to the invention, the manufacture of the printable layer is therefore performed independently of that of the base substrate. This allows in particular to implement the process with standard industrial tools, which allows optimal production speeds.

The smooth face of the sheet may have a Bekk smoothness greater than about 900 or 1000s, preferably greater than 2000s, and more preferably greater than 5000s. In the present application, the term "smooth or ultra-smooth face" is understood to mean a face having a Bekk smoothness greater than about 900 or 1000s, advantageously greater than 2000s, and more preferably greater than 5000s.

This smooth face may have a gloss of greater than 70%, and preferably greater than 80%, this brightness being for example measured at 75 according to the TAPPI® T480 om-92 method. This gloss may be similar to or even greater than that of a photographic paper of the resin-coated type, comprising a plastic film.

The multilayer structure may comprise at least one additional layer deposited on the printable layer, on the opposite side to the plastic film, the free face of this additional layer or of the layer the furthest from the plastic film being intended, in step b /, to be glued and applied against the aforementioned face of the substrate.

The additional layer or layers may be functional or non-functional. They may for example be insulating (dielectric) or form a barrier (to gases, for example oxygen, liquids, for example water, grease, etc.).

In the case where the multilayer structure comprises a single additional layer, it is deposited on the upper face of the printable layer, that is to say on the face of the printable layer, located on the opposite side to the plastic film of the multilayer structure. This additional layer can be of any kind, and is therefore not necessarily printable. In the case where the multilayer structure comprises two or more additional layers, these additional layers are superimposed on each other and deposited on the aforementioned upper face of the printable layer. The technique or techniques used to deposit the additional layer or layers on the printable layer may be of the aforementioned types, or of any other type.

The multilayer structure can therefore comprise in addition to the three aforementioned elements (a plastic film, a release layer, and a printable layer), one or more additional layers, which are printable or not, on the printable layer (on the opposite side to the plastic film ). The multilayer structure may further comprise a layer or film of glue covering the layer furthest from the plastic film (i.e., the printable layer or the or an additional layer).

Step b / of the method according to the invention consists in gluing the face of the substrate intended to receive the printable layer, or the face of the multilayer structure, located on the opposite side to the plastic film, and to apply these faces against each other. the other, so as to fix them.

The substrate may be selected from paper, tracing paper, card stock, and coated or precoated paper. The paper may have a relatively large hand greater than or equal to 1, 10cm ³ / g, preferably greater than or equal to 1.2 cm ³ / g, more preferably greater than or equal to 1.3 cm ³ / g, more particularly greater than or equal to 1.4 cm ³ / g, and even more particularly greater than or equal to 1.5 cm ^3; /boy Wut.

The method according to the invention makes it possible to produce a sheet having both a large hand and a smoothing, which was not possible with the prior art. It was indeed not possible in the prior art to make a sheet with a large hand and a high surface quality. A substrate having a large hand can be formed of an inexpensive material. In the case of paper, the pulp used may comprise cellulosic fibers, a binder, and a small proportion of fillers and / or adjuvants, such as starch.

In a particular embodiment of the invention, the process according to the invention results in a slight decrease of about 2 to 5% in the hand of the paper substrate.

A smooth or ultra smooth sheet with a large hand, made with the method according to the invention, has good printability and low basis weight, which allows for lightweight packaging but having a relatively high rigidity.

During step b1 of the method, the face to be coated with the substrate or the free face of the printable layer or of an additional layer of the multilayer structure is glued by means of a suitable glue.

As a variant, the two aforementioned faces of the substrate and of the multilayer structure are glued simultaneously, or one after the other.

Sizing consists in depositing a layer of adhesive on the above-mentioned face or faces by any technique, such as, for example, gravure printing. The glue may be of the thermal, non-thermal type, by UV crosslinking or by chemical reaction. The adhesive may be deposited on the or each of the aforementioned surfaces in liquid or non-liquid form (in the case for example of a thermoadhesive film). This glue is for example chosen from the following polymers: acrylic, polyurethane, polymethyl methacrylate, styrene butadiene, vinyl acetate, polyamide, nitrocellulose or any other cellulose, polyvinyl alcohol or starch. The or each deposited adhesive layer may have a thickness less than or equal to 10 μm, and preferably less than or equal to 3 μm.

In a particular embodiment of the invention, the adhesive is deposited on the aforementioned face of the multilayer structure during the preparation of this structure. This glue is then part of the entire multilayer structure. The adhesive may be formed by a heat-activatable adhesive layer, this layer being activated by heating during the application of the multilayer structure on the substrate (receiver).

The nature of the glue and the gluing process (on the film and / or on the paper) can have a significant influence on the final surface state of the paper. It is for example important that the removal of the glue is uniform and avoid the formation of cavities between the paper and the printable layer.

Regarding the uniformity of the removal of the adhesive, the removal of the adhesive is preferably homogeneous to avoid excess and / or lack of adhesive in places, which would result in a final sheet having surface roughness. Advantageously, the glue spreads perfectly on the support (film or paper) having an adequate surface tension and rheology.

The method of coating the glue can also be important. Coating modes that generate the least possible heterogeneity of deposit, such as gravure printing (reverse roll or kiss coating) are preferred. The deposit is preferably chosen to fill the pores or surface irregularities of the paper as much as possible. For example, when a paper has an average surface roughness (for example Sa) of approximately 20 μm, an adhesive removal having a thickness of at least 10 μηη is preferable for filling the pores. The deposition of glue is preferably performed on the paper when the latter is too rough. If the deposit on the paper is insufficient, cavities are formed between the surface of the paper and the printable layer. When printing, these cavities go become points of fragility of the paper which can then be sinking, if one exerts a pressure, or tear, if one exerts a traction.

Advantageously, the thickness of glue deposited on the paper and / or the printable layer is equal to at least half of the average surface roughness (for example Ra or Sa) of the paper. In one embodiment of the invention, the adhesive is deposited on at least one side of the substrate in step b /, and the thickness of the deposited adhesive layer is at least equal to half the average roughness of the substrate. the face of the substrate, and is preferably equal to this average roughness.

The adhesive can be aqueous-based, solvent-free, solvent-free, two-component or monocomponent.

The adhesive makes it possible to fix the printable layer (or an additional layer) on the substrate and, if necessary, to compensate for the surface irregularities of the substrate. The glue fills in particular the hollows of the face to be coated with the substrate and thus makes it possible to smooth this face, without however modifying the characteristics of the substrate, such as its hand.

Step b / of the method then consists in applying the aforementioned face of the substrate to the aforementioned face of the multilayer structure, so as to laminate or laminate them. The printable layer is then sandwiched between on the one hand the substrate and the glue (and optionally one or more additional layers), on one side, and on the other hand the plastic film and the non-stick layer, of the 'other side.

In the case where the adhesive used to bond the substrate to the multilayer structure is of the thermoadhesive type, the application of the substrate to the multilayer structure is carried out hot, at a given temperature, which is for example between 50 and 200 ° C. about. Alternatively, the application and bonding of the substrate to the multilayer structure can be performed at room temperature.

A slight pressure may be necessary to ensure good adhesion of the printable layer on the substrate, through the glue. The temperature and / or the pressure used during the application and the gluing must not, however, modify the characteristics of the printable layer, and in particular the surface state of its face located on the side of the plastic film. For example, the printable layer should not be softened by the application of a high temperature, as this could cause a change and / or a decrease in the surface quality of its face, located on the side of the plastic film.

The step c1 of the method then consists in removing the plastic film from the printable layer and from the substrate, so that the printable layer (and optionally the aforementioned additional layer or layers of the multilayer structure) remain on the substrate. The printable layer, and if necessary the additional layer or layers, are therefore transferred from the plastic film called donor, of the multilayer structure, to the substrate called the receiver.

As explained above, at least a portion and advantageously most or all of the release layer can remain on the plastic film and is then removed from the printable layer, during removal of the plastic film. The face of the printable layer, which was located on the side of the plastic film in the multilayer structure, is thus exposed, this face defining the smooth face of the sheet.

Transfer of the printable layer of the multilayer structure to the substrate, at steps b1 and c1 of the method, can be carried out as follows, when the substrate and the multilayer structure are in the form of continuous strips.

The rolling or lamination of the multilayer structure and the substrate can be achieved by passing these two elements between two parallel and adjacent mechanical rollers rotating in opposite directions. The thickness of the product obtained is in particular a function of the distance between the rollers. Once the glue is dry or solidified, the plastic film is removed from the sheet while the sheet is driven by another mechanical roller. Alternatively, it is possible to glue either the multilayer structure or the substrate, to dry the glue, then to bring these two elements into contact with each other by applying a determined temperature and pressure.

The method may further consist in that, before step b /, the aforementioned face of the substrate is precoated with at least one smoothing layer comprising one or more thermoplastic polymers (such as at least one polystyrene, one polyurethane, one acrylic, etc.) or a mixture of pigments (such as kaolins, calcium carbonates, talc, titanium dioxide, etc., and mixtures thereof) and at least one binder (such as acrylic, polyurethane, polymethyl methacrylate, styrene butadiene, vinyl acetate, polyamide, nitrocellulose or any other cellulose, starch or PVA).

This precoated surface of the substrate may also be calendered, before step b /, to increase its smoothness.

The method according to the invention may comprise an additional step of printing the sheet with an ink having electrical and / or optical properties.

The present invention further relates to a process for preparing a multilayer structure comprising at least or consisting of a plastic film, a release layer, and a printable layer, the release layer being interposed between the plastic film and the printable layer.

The present invention also relates to a process for printing a sheet prepared by the method described above, this process comprising a step of printing the sheet without modifying the state of its printable layer, ie without softening or melting this layer during printing. The sheet is for example printed by offset, inkjet, laser, gravure, flex, dry toner, liquid toner, electrophotography, lithography, etc. The present invention furthermore relates to a method for producing a casting sheet having at least one smooth surface, said sheet comprising a substrate, in particular of paper, at least one surface of which is covered at least in part with a layer or a plurality of superposed layers, the process comprising the steps of: a / preparing or providing a multilayer structure comprising at least, or consisting of, a plastic film, a release layer, and a casting application layer, the release layer being interposed therebetween between the plastic film and the layer for casting application,

b / bonding a face of the substrate and / or the face of the multilayer structure located on the opposite side to the plastic film, and applying the aforementioned face of the substrate against the aforementioned face of the multilayer structure, so as to laminate the multilayer structure and the substrate , and

Remove the plastic film from the casting application layer, this layer defining said smooth face of the sheet.

The layer for casting application is for example a layer of PVA. The casting application layer may have anti-adhesive properties.

The present invention also relates to a printable sheet having at least one smooth face, and advantageously ultra smooth, this sheet comprising a substrate, in particular of paper, of which at least one face is covered at least in part by one or more layers, of which a printable layer defining said smooth or ultra-smooth face, characterized in that this smooth or ultra-smooth face has a Bekk smoothness greater than 900s or greater than about 1000s, preferably greater than 2000s, and more preferably greater than 5000s.

The smooth or ultra-smooth face of the sheet may have a gloss of greater than 70%, and preferably greater than 80%, this brightness being measured, for example, at 75 ° according to the TAPPI T480 om-92 method.

The printable layer of the sheet may have a thickness less than or equal to 30 μm, preferably less than or equal to 15 μm, and more preferably less than or equal to 10μηη. The grammage of the printable layer may be less than or equal to 30 g / m ² , preferably less than or equal to 15 g / m ² , and more preferably less than or equal to 10 g / m ² . The printable layer may for example have a thickness and a grammage that are less than or equal to the following combined values: 10μηη and 10g / m ² , 3μηη and 10g / m ² , 2μηη and 10g / m ² , 5μηη and 5g / m ² , 3μηη and 3g / m ² , 2μηη and 5g / m ² , 5μηη and 2g / m ² , 3μm and 2g / m ² , or 2μm and 2g / m ² .

The present invention also relates to the use of a printable sheet as described above, for the production of an electronic and / or optical component, this sheet being printed by means of an ink having electrical properties and / or optics.

The sheet according to the invention can be compatible with electronic organic inks for electronic applications, such as for example the realization of RFID (Radio Frequency IDentification) chips, display or detection systems, etc., directly on the sheet.

In the prior art, an RFID chip could be made on a sheet formed of a polyethylene terephthalate (PET) plastic film. However, this plastic film has a relatively low mechanical strength and temperature, which limits the possible applications of the chip and prevents printing of the film with inks at relatively high temperatures. In addition, the PET film is not recyclable in a simple way. On the contrary, when the substrate of the sheet according to the invention is made of paper, this sheet has a better mechanical strength and at high temperatures.

A sheet printed with an ink having electrical properties advantageously comprises a flexible substrate and a printable layer with little or no electrically conductive effect. This type of sheet can be used to produce thin film organic transistors using conductive or semiconducting organic inks. The sheet according to the invention can also be used for producing optical components, such as waveguides, holographic patterns, etc.

By way of example, the process defined above can comprise, before step a /, a preliminary step consisting in producing, for example by etching, recessed and / or embossed patterns on the face of the plastic film intended receiving the release layer and the printable layer, the printable layer being adapted to conform to the shape of these patterns so as to include a print of the aforementioned side of the plastic film.

In this case, the transfer of the surface condition of the film to the printable layer comprises both a transfer of the smoothness and patterns of the plastic film. The patterns transferred onto the printable layer themselves have surfaces and / or walls having a smooth appearance and being precisely defined. This method is then particularly advantageous for the production of optical components of the aforementioned types.

The present invention finally relates to the use of a printable sheet as described above, for the printing of a photographic image, for the production of a package, and / or for a casting application.

The invention will be better understood and other details, characteristics and advantages of the present invention will emerge more clearly on reading the following description given by way of nonlimiting example and with reference to the appended drawings in which:

FIG. 1 very schematically represents steps of the method according to the invention for manufacturing a smooth or ultra smooth printable sheet;

FIG. 2 very schematically represents an alternative embodiment of the method according to the invention;

FIGS. 3 and 4 show very schematically means for implementing the transfer step of the method according to the invention; and FIGS. 5 and 6 are images obtained by a scanning electron microscope (SEM) of a face of a base paper and a face of a smooth or ultra-smooth sheet obtained by the process according to the invention; .

Referring first to Figure 1 which shows schematically steps a /, bl and cl of the method according to the invention for manufacturing a printable sheet smooth or ultra smooth 10 and fully recyclable.

Step a / of the process consists in preparing a multilayer structure 12 comprising a lower plastic film 14, a nonstick interlayer 16 and a printable top layer 18. The preparation of this structure 12 can be carried out in one or more successive steps.

The nonstick layer 16 and the printable layer 18 can be simultaneously deposited on the plastic film 14, for example by a curtain coating technique.

Alternatively, the release layer 16 is deposited on the plastic film 14, then the printable layer 18 is deposited on the release layer.

The surface quality of the upper face 20 of the plastic film 14 is transmitted to the underside 22 of the printable layer 18 (via the release layer 16). The surface characteristics of the face 22 of the printable layer are therefore defined by those of the face 20 of the plastic film 14.

For example, the roughness of films and papers were tested using a device measuring the topography type ALTISURF 500 ALTIMET company. The first film tested has a roughness (for example Sa) of 1 μηη. This film was used to transfer a printable layer to Bristol® paper from Arjowiggins. The measured roughness of this printable layer is 1.1 m. The second film has a roughness of Ο, δμιτι. This film was used to transfer a printable layer to another Bristol® paper. The measured roughness of this printable layer was 0.7μηη. The roughness (or the surface condition) of the film has therefore been transferred from the films to the printable layers. After drying and / or solidification of the printable layer, the surface characteristics of the face 22 are fixed and are not intended to be modified during the other steps of the method, and in particular the transfer of the printable layer 18 onto a substrate 24 , such as paper, to be coated.

The printable layer 18 may be formed of a printable resin or varnish or a papermaking coating comprising a binder and pigments. Alternatively, the printable layer may comprise two or more sub-layers which are selected from a printable varnish and a paper coating. In the case where the printable layer comprises two sub-layers: a printable varnish and a paper coating, the printable varnish is located above or below the paper coating, so that the underside 22 above of the printable layer is defined by printable varnish or paper coating.

The step b1 of the process consists in depositing a layer or a film of adhesive 26 on the upper face 28 of the printable layer 18 or on the lower face 30 to be coated on the substrate 24, or even on these two faces 28, 30, then on applying these faces 28, 30 against each other to laminate or laminate the multilayer structure 12 and the substrate 24, and thus form a rolled or laminated product 32.

The step c1 of the method consists in removing the plastic film 14 and the nonstick layer 16 from the printable layer 18, so that only this layer 18 remains (with the adhesive 26) on the substrate 24.

These steps b / and c / can be performed simultaneously or one after the other. In the latter case, the adhesive 26 is advantageously in the dry state and / or solidified during the removal of the plastic film 14.

At the end of step c1, the face 22 of the printable layer 18 is exposed, this face being smooth or ultra smooth. A portion of the release layer 16 may, however, remain on the face 22 of the printable layer 18 after removal of the plastic film.

The layer 18 is printable by any appropriate technique, the ink being intended to be deposited on the smooth or ultra smooth face 22 of the sheet 10.

Alternatively, the substrate 24 may be formed of a coated or precoated paper, that is to say a paper on one side of which a layer or precoat 33 is deposited, the latter comprising one or more thermoplastic polymers or a mixture of pigments and binder. This layer or precoat 33 is intended to be deposited on the aforementioned face 30 of the substrate, and is advantageously smoothed by calendering. It is then intended to be glued on the face 28 of the printable layer 18.

FIG. 2 represents an alternative embodiment of the method according to the invention, and differs from the method previously described with reference to FIG. 1, in particular in that the multilayer structure 12 'furthermore comprises at least one additional layer 34 deposited on the face upper 28 of the printable layer 18.

Several additional superimposed layers 34 may be deposited (simultaneously or successively) on the face 28 of the printable layer 18. Each of the additional layers 34 may be printable or non-printable.

In step b /, the lower face 30 of the substrate 24 or the free upper face 36 of the additional layer 34 (furthest from the plastic film, in the case where the structure 12 'comprises several additional layers) is covered with 26. Alternatively, these two faces 30, 36 are covered with glue 26.

In step c /, the multilayer structure 12 'and the substrate 24 are laminated or laminated, so as to form a rolled or laminated product 32', then the plastic film 14 and the release layer are removed, so as to to bare the smooth or ultra smooth face 22 of the printable layer 18 of the sheet 10 '. As is the case in FIG. 1, the sheet of FIG. 2 may comprise a substrate 24 precoated on its face 30, in order to increase its smoothness. The precoat 33 is of the same type as that described with reference to FIG.

Figures 3 and 4 show schematically means for implementing the c / transfer step of the method according to the invention.

A first roll 40 is provided for driving a continuous strip of the multilayer structure 12 (formed of a plastic film 14, a non-stick layer 16 and a printable layer 18 - and optionally layer (s) additional 34). A second roller 42, parallel and adjacent to the first roller 40, is provided for driving a continuous strip of the substrate 24.

The rollers 40, 42 rotate in opposite directions and are at a small distance from each other, the multilayer structure 12 and the substrate 24 being forced to pass between these rollers and being applied at a given pressure against each other. other, to ensure their rolling or lamination.

The adhesive 26 may be deposited on the multilayer structure 12 and / or the substrate 24, as indicated in the foregoing, prior to this lamination step, or during this lamination step. In the latter case, the glue 26 may be injected between the structure 12 and the substrate, prior to their passage between the rollers, as is schematically represented by the double arrow in FIG.

A third roller 44 drives in one direction the sheet 10 formed by the substrate 24 and the printable layer 18, while the plastic film 14 and the release layer 16 are driven in another direction to separate them from the sheet 10.

FIGS. 5 and 6 are images obtained by a scanning electron microscope (SEM) of a face of a paper or base substrate 24 and a smooth or ultra-smooth face of a sheet 10, produced by the method according to the invention, respectively. The base paper (Figure 5) is here formed of cellulosic fibers intermingled with each other and defining a rough face. The roughness Sz of this face is of the order of 19,7μηη, which means that the maximum surface height, from the highest point to the deepest valley is equal to 19,7μηη.

The sheet according to the invention (FIG. 6) has a smooth or ultra-smooth face defined by its printable layer which has a roughness Sz of the order of Ι, ΟΊ μηη, which is comparable to that of a paper coated with a plastic film, according to the prior art, which has a roughness Sz of the order of 1, 5μηη.

This roughness value of Ι, ΟΊ μηη of the sheet according to the invention is given for information only and illustrates a particular embodiment of the invention.

Other examples illustrating the present invention will now be described in the following

Example 1: Preparation of a Smooth or Ultra Smooth Sheet Printable by Offset

A smooth or ultra-smooth sheet according to the invention was prepared for offset printing from a printable layer A having the following composition:

Composition of the layer A

Pigments Calcium carbonate 1248g

Hydrocarb® 60 OG (Omya)

Binder Aqueous dispersion of n-butyl copolymer 300g

acrylate-acrylonitrile-styrene

Acronal® S504 (BASF)

Dispersant Sulfoccinic acid - isooctyl ester, salt of 3g

sodium

Agnique® EHS 75E (Cognis)

Rheological modifier Aqueous dispersion of acrylic copolymer 0.6g

Sterocoll® FD (BASF)

Spreading agent Nonionic surfactant 0.2g

Surfynol® 420 (Safic-Alcan) The printable layer A has a final concentration by weight of 50% and a viscosity of 100cps, measured using a Brookfield® viscometer.

The layer A is applied on one side of a PET plastic film, which is previously coated with a non-stick layer based on chromium stearyl chloride. The removal of the layer A on the film is about 10 g / m ² . Layer A is then dried in an oven at 70 ° C. A multilayer structure consisting of the PET plastic film, a non-stick layer of stearic chromium chloride and the printable layer A is then obtained.

The free face of the layer A, that is to say the face located on the opposite side to the plastic film, is glued with a Super-Lok® 364 glue from the company National Starch. The adhesive is deposited at a rate of 3 g / m ² on the layer A. The glued face of the layer A is applied against a substrate formed by a Bristol® paper 335 g / m ² manufactured by the Arjowiggins company, then the whole is dried. in an oven at 70 ° C. The process step b1 is then complete.

The plastic film and the nonstick layer are then removed (in step c1) leaving only the printable layer A and the adhesive on the paper substrate.

The prepared sheet is printable by Offset. It is not printable by heat transfer. This was confirmed by a sheet-printing test obtained in Example 1 with a Canon Selphy CP800 thermal transfer printer. Transfers of yellow, cyan and magenta were bad, and the black did not transfer at all. The final image was not acceptable. Example 2 Preparation of a Smooth or Ultra Smooth Sheet Printable by Offset, from a Bulky Paper or Having a Relatively Large Hand

The printable layer A of Example 2 is prepared and applied in the same manner and under the same conditions as those discussed in Example 1, on a Bulk Paper Elementa® bulk from Arjowiggins. This paper has an initial hand of 1, 4cm ³ / g. Example 3 Preparation of an Offset Printable Smooth or Ultra-Smooth Sheet from a Precut Backing Paper

The printable layer A of Example 3 is prepared and applied in the same manner and under the same conditions as those discussed in Example 1, on a Maine Gloss® precooked paper from Arjowiggins. This paper has an initial Bekk smoothness of 400s.

Example 4 Preparation of a Smooth or Ultra Smooth Colored Sheet Printable by Offset

A smooth or ultra-smooth colored sheet according to the invention for Offset printing was prepared from a printable layer B having the following composition:

The printable layer B has a final concentration by weight of 50% and a viscosity of 100cps, measured using a Brookfield® viscometer.

The layer B is applied on one side of a PET plastic film which is previously coated with a non-stick layer based on chromium stearo chloride The removal of the layer B on the film is about 10g / m ² . The layer B is then dried in an oven at 70 ° C. A multilayer structure consisting of the PET plastic film, a non-stick layer made of stearic chromium chloride and the printable layer B, is then obtained.

The free face of the layer B, that is to say the face located on the side opposite to the plastic film, is glued with a Super-Lok® 364 glue from the company National Starch. The adhesive is deposited at a rate of 3 g / m ² on the layer B. The glued face of the layer B is applied against a substrate formed by a Bristol® 335g / m ² paper manufactured by the Arjowiggins company, then the whole is dried. in an oven at 70 ° C.

The plastic film and the nonstick layer are then removed leaving only the printable layer B and the adhesive on the paper substrate.

The paper obtained has a very homogeneous coloring.

EXAMPLE 5 Preparation of a Smooth or Ultra-Smooth Sheet Printable by Offset and with Low Surface Resistivity

A smooth or ultra-smooth sheet according to the invention with low surface resistivity and Offset printing was prepared from a printable layer C having the following composition:

Composition of the printable layer C

Pigments Calcium carbonate 1248g

Hydrocarb® 60 OG (Omya)

Binder Aqueous dispersion of n-butyl copolymer 300g

acrylate-acrylonitrile-styrene

Acronal® S504 (BASF)

Dispersant Sulfoccinic acid - isooctyl ester, salt of 3g

sodium

Agnique® EHS 75E (Cognis)

Conductive additive Aqueous dispersion of a polymer 3 g

driver

Clevios® P (H.C. Starck)

Rheological modifier Aqueous dispersion of acrylic copolymer 0.6g

Sterocoll® FD (BASF) Spreading agent Nonionic surfactant 0.2g

Surfynol® 420 (Safic-Alcan)

The printable layer C has a final concentration by weight of 50% and a viscosity of 100cps, measured using a Brookfield® viscometer.

The layer C is applied on one side of a PET plastic film which is previously covered with a non-stick layer based on stearo chromium chloride. The deposit of the layer C on the film is about 10 g / m ² . The layer C is then dried in an oven at 70 ° C. A multilayer structure consisting of the PET plastic film, a non-stick layer of stearic chromium chloride and the printable layer C is then obtained.

The free face of the layer C, that is to say the face located on the opposite side to the plastic film, is glued with a Super-Lok® 364 glue from the company National Starch. The adhesive is deposited at a rate of 3 g / m ² on the layer C. The glued face of the layer C is applied against a substrate formed by a Bristol® 335 g / m ² paper manufactured by Arjowiggins, then the whole is dried. in an oven at 70 ° C.

The plastic film and the nonstick layer are then removed leaving only the printable layer C and the adhesive on the paper substrate.

The resistivity of the paper thus obtained is relatively low, and is of the order of 3.10 ⁷ . This resistivity is lower than that of the paper of Example A, which is of the order of about 10 ¹⁰ .

Example 6 Preparation of a Smooth or Ultra Smooth Sheet Printable by Inkjet

A smooth or ultra-smooth sheet according to the invention for inkjet printing was prepared from a printable layer D having the following composition: compounds

Alumina Pigments 1000g

Disperal HP14-2 (Sasol)

Binder Polyvinyl Alcohol 100g

Mowiol 47-88 (Seppic)

Nonionic surfactant 1g

Surfynol® CT211 (Safic-Alcan)

The printable layer D has a final concentration by weight of 14% and a viscosity of 50cps, measured using a Brookfield® viscometer.

The layer D is applied on one side of a PET plastic film which is previously covered with a non-stick layer based on chromium stearo chloride. The deposit of the layer D on the film is about 15 g / m ² . The D layer is then dried in an oven at 70 ° C. A multilayer structure is thus obtained constituted by the PET plastic film, a non-stick layer made of stearochromium chloride and the printable layer D.

The free face of the layer D, that is to say the face located on the opposite side to the plastic film, is glued with a Super-Lok® 364 glue from the company National Starch. The glue is deposited at a rate of 3 g / m ² on the layer D. The glued face of the layer D is applied against a substrate formed by a Bristol® paper 335 g / m ² manufactured by Arjowiggins, then the whole is dried. in an oven at 70 ° C.

The plastic film and the nonstick layer are then removed leaving only the printable layer D and the adhesive on the paper substrate.

Results: The various sheets prepared in Examples 1 to 6 were analyzed and the following parameters of the sheet were measured: weight, thickness, hand, smoothness, gloss, resistivity and printability.

The measurements were carried out as follows:

the basis weight was measured according to ISO 536 (1976), using a Sartorius® scale with a range of 2200 g and an accuracy of 0.1 g; the thickness was measured according to ISO 534 (1988), by means of an MTS MI20 micrometer;

the hand (or mass volume) has been measured according to standard NFQ 03-017;

- Bekk smoothness was measured according to ISO 5627 (1984), using a Buchel® 131 ED;

the gloss was measured at 75 ° according to the TAPPI® T480 om-92 method, using a Byk-Gardner® micro-gloss 75 ° model 4553 apparatus;

the surface resistivity was measured according to the ASTM D257-83 method, using a Philips PM2525 Multimeter apparatus;

Offset printability was evaluated by an absorption test with porometric inks according to a CTP method No. 9; the "porometric ink" test makes it possible to quantify the absorption capacity of a paper and the speed of penetration of the ink of this paper; it is based on the deposit of a special ink, consisting of a black dye, on the paper and on the study of its behavior over time; and

- The inkjet printing tests were carried out with Epson 2400 and Canon iP 8500 inkjet printers.

The table below summarizes all the measurements and analyzes carried out on the sheets of Examples 1 to 6.

unmeasured parameters)

The transfer of a printable layer (A to D) on a support causes an increase in the basis weight and thickness of this support. The increase in grammage is of the order of 30 to 40 g / m ² in the case of the layer A, 126 g / m ² in the case of the layer B, 41 g / m ² in the case of the layer C, and 24g / m ² in the case of the layer D. The increase in thickness is of the order of 20 to 33μηη in the case of the layer A, ΘΟμιτι in the case of the layer B, 64μηη in the case of the layer C, and 84μηη in the case of the layer D. The increase in the basis weight and thickness of the support is mainly due to the addition of glue and the transfer of the printable layer on this support.

A paper has a relatively large hand when it has a value greater than or equal to 1, 10cm ³ / g. In the aforementioned examples, only Elementa® bulk paper has a large hand (1, 4cm ³ / g).

Deposition of the printable layer A on a support causes a decrease in his hand. When the support initially has a large hand, as is the case of Elementa® bulk in Example 2, the transfer of the layer A on this support causes a slight decrease of his hand (of the order of 5%) . The hand of the Elementa® bulk support comprising the layer A remains however very important (1, 33cm ³ / g, that is to say greater than 1, 10cm ³ / g).

The deposition of the printable layer B on a support causes a decrease in his hand, while the deposition of the printable layer C on a support has little influence on his hand. Deposition of the printable layer D on a support causes an increase in its hand because the printable layer is here an inkjet layer which is very porous and therefore has a low density.

Bristol® and Elementa® bulk papers initially have a relatively low smoothness, less than 100s. Maine Gloss® precoated paper initially has a relatively high smoothness of 400s thanks to its precoat based on calcium carbonate and styrene butadiene latex. The transfer of a printable layer on a support, by means of the method according to the invention, makes it possible to give the support a smooth or ultra-smooth face, as explained in the foregoing.

The transfer of the printable layer A on a paper support considerably increases its smoothness. It can be seen that the printable layer A makes it possible to confer on a paper with a strong hand a very important smoothness (50% in Example 2). The method according to the invention therefore makes it possible to produce a paper having both a large hand and a smoothing.

It is also noted that the higher the initial smoothness of the support, the greater the smoothness of the support on which the layer A is transferred. The layer A transferred on a Maine Gloss® paper makes it possible to give this paper a very high smoothness of 9436s.

The transfer of the D layer on a Bristol® support increases its smoothness to around 1000s.

The sheets prepared in Examples 1 to 6 all have a high gloss, greater than 80%. The method therefore makes it possible to produce sheets having both a high degree of smoothness and gloss.

The presence of conductive additive in the layer C significantly reduces the surface resistivity of the sheet. The sheet of Example 5 has a surface resistivity which is approximately 1000 times lower than that of the sheets of Examples 1 and 4. This additive makes it possible to increase the electrical conductivity of the sheets and thus to envisage the production of electro-magnetic sheets. conductive.

With regard to the Offset printability of the sheets prepared in Examples 1 to 5, the porometric ink test shows that the papers have relatively correct optical density values after inking, even if they do not increase over time. , thus showing limited absorption.

With regard to the inkjet printable paper, prepared in Example 6, Epson and Canon inkjet printer tests show correct results despite low shrinkage. Example 7 Preparation of a Smooth or Ultra-Smooth Printable Sheet Containing a Varnish or Printable Resin

A smooth or ultra-smooth sheet according to the invention was prepared from a printable layer formed by a lacquer or an acrylic printable resin E having the following composition. This sheet is printable by Offset.

The printable lacquer E has a final concentration by weight of 50% and a viscosity of 50cps, measured using a Brookfield® viscometer.

The varnish E is applied on one side of a PET plastic film, which is previously coated with a nonstick layer based on stéaro chromium chloride. The removal of the varnish on the film is about 5g / m ² . The varnish is then dried in an oven at 70 ° C. A multilayer structure consisting of PET plastic film, a non-stick layer of stearic chromium chloride and acrylic lacquer is then obtained.

The free face of the varnish is glued with a Super-Lok® 364 glue from National Starch. The adhesive is deposited at a rate of 3g / m ² on the varnish. The glued face of the varnish is applied against a substrate formed by Bristol® 335g / m ² paper manufactured by Arjowiggins, then the whole is dried in an oven at 70 ° C. The plastic film and the layer nonstick are then removed (in step c) to leave only the printable varnish and glue on the paper substrate.

The table below summarizes the measurements and analyzes carried out on the sheets prepared by this example 7.

The transfer of the printable varnish E on the support modifies little the weight, the thickness and the hand of this support. This transfer makes it possible to produce a sheet with a smoothness (> 10,000s) and a gloss (99%) very high. The printability of this sheet is however lower than those prepared in Examples 1 to 6 because of the absence of pigments in the printable layer.

EXAMPLE 8 Preparation of Smooth or Ultra Smooth Printable Sheets by Offset, Indigo, or Electro-Conductive Inks

Each prepared sheet here comprises two printable layers AA, AB or AC, a first layer (A, B or C) deposited (by kiss coating) on the nonstick layer of the multilayer structure and a second layer (A) deposited (by kiss coating ) on the first layer. The first layer, that is to say the layer closest to the plastic film in the multilayer structure, is the layer intended to directly receive the inks during printing. It defines the printability according to the printing process. The second layer is a precoat allowing a good adhesion of the first layer on the support and forming a barrier to the glue (to prevent it from entering the first printable layer).

The plastic film used is a PET film 12μηη thick. The printable layers for the preparation of an offset printable sheet are a first layer B, and a second layer A. The printable layers for the preparation of an HP Indigo printable sheet are a first layer C, and a second layer A The printable layers for the preparation of a printable sheet by electrically conductive inks (Printed Electronics) are a first layer A, and a second layer A. The multilayer structures prepared are of the PET / non-stick layer / layer A & A or C & A type or B & A. Layers A, B and C are deposited at a rate of 6 g / m ² .

The compositions of these layers are detailed in the following tables.

Composition of the printable layer A

Pigments Calcium Carbonate 475ml

Carbital® 95 (Imerys)

Binder 1 aqueous dispersion of styrene-190ml copolymer

butadiene

Styronal® D517 (BASF)

Binder 2 Dispersion aqueous copolymer n-butyl 94ml

acrylate-acrylonitrile-styrene

Acronal® S 305 (BASF)

Dispersant Sulfoccinic acid - isooctyl ester, salt of 3g

sodium

Agnique® EHS 75E (Cognis)

Rheological modifier Aqueous dispersion of acrylic copolymer 0.6g

Sterocoll® FD (BASF)

Spreading agent Nonionic surfactant 0.2g

Surfynol® 420 (Safic-Alcan) Composition of the printable layer B

Pigments Calcium Carbonate 475ml

Carbital® 95 (Imerys)

Binder 1 aqueous dispersion of styrene-95ml copolymer

butadiene

Styronal® D517 (BASF)

Binder 2 Aqueous dispersion of n-butyl copolymer 47ml acrylate-acrylonitrile-styrene

Acronal® S 305 (BASF)

Dispersant Sulfoccinic acid - isooctyl ester, 3g sodium salt

Agnique® EHS 75E (Cognis)

Rheological modifier Aqueous dispersion of acrylic copolymer 0.6g

Sterocoll® FD (BASF)

Spreading agent Nonionic surfactant 0.2g

Surfynol® 420 (Safic-Alcan)

Composition of the printable layer C

Pigments Calcium Carbonate 475ml

Carbital® 95 (Imerys)

Binder 1 aqueous dispersion of styrene-95ml copolymer

butadiene

Styronal® D517 (BASF)

Acronal® S 305 (BASF)

Adhesion Promoter Aqueous Acrylic Acid Dispersion - 280 ml

Ethylene Diamond® 63001 (NALCO)

Dispersant Sulfoccinic acid - isooctyl ester, 3g sodium salt

Agnique® EHS 75E (Cognis)

Rheological modifier Aqueous dispersion of acrylic copolymer 0.6g

Sterocoll® FD (BASF)

Spreading agent Nonionic surfactant 0.2g

Surfynol® 420 (Safic-Alcan) Each of the three multilayer structures and a 200 g / m ² Opale® paper from Arjowiggins were laminated with a two-component polyurethane adhesive deposited at a rate of 10 g / m ² .

The sheets obtained have good printability according to their applications, that is to say for offset, for the digital HP Indigo and for conductive inks (printed electronics).

Claims

1. A method of manufacturing a printable sheet (10) having at least one smooth face (22), said sheet comprising a substrate (24), in particular of paper, at least one side of which is covered at least in part with a layer or a plurality of superposed layers, the method comprising the steps of:

a / preparing or providing a multilayer structure (12) comprising at least or consisting of a plastic film (14), a release layer (16), and a printable layer (18), the release layer being interposed between the plastic film and the printable layer,

b / bonding a face (30) of the substrate and / or the face (28) of the multilayer structure located on the opposite side to the plastic film, and applying the aforementioned face of the substrate against the aforementioned face of the multilayer structure, so as to counterpick the multilayer structure and the substrate, and

c / removing the plastic film from the printable layer, the printable layer (18) defining said smooth face (22) of the sheet.

2. Method according to claim 1, characterized in that the printable layer (18) is in the solid state and / or dry in step b / and / or in step c1.

3. Method according to claim 1 or 2, characterized in that the substrate (24) is selected from paper, tracing paper, card stock, and coated or precoated paper.

4. Process according to claim 3, characterized in that the paper has a hand greater than or equal to 1.10 cm ³ / g, preferably greater than or equal to 1.2 cm ³ / g, and more preferably greater than or equal to 1 , 3cm ³ / g.

5. Method according to one of the preceding claims, characterized in that, before step b /, the aforementioned face of the substrate is precoated with at least one smoothing layer comprising one or more thermoplastic polymers or a mixture of pigments and dyes. at least one binder.

6. Method according to claim 5, characterized in that, before step b /, the precoated surface of the substrate is calendered to increase its smoothness.

7. Method according to one of the preceding claims, characterized in that the plastic film (14) is selected from a film of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), d-based polymer polylactic acid (PLA), or any cellulose-based polymer.

8. Method according to one of the preceding claims, characterized in that the release layer (16) is based on silicone (s), siloxane (s), polysiloxane (s) or its derivatives, complex (s) Werner such as chromium stearyl chlorides, or polyethylene, propylene, polyurethane, polyamide, polytetrafluoroethylene waxes, or a mixture thereof.

9. Method according to one of claims 1 to 8, characterized in that the release layer (16) is at least partially removed from the printable layer (18) during removal of the plastic film (14) in step cl .

10. Method according to one of the preceding claims, characterized in that the release layer (16) remains on the printable layer (18) during removal of the plastic film (14) in step cl.

1 1. Method according to one of the preceding claims, characterized in that the printable layer (18) comprises a mixture of pigments and at least one binder or a printable varnish, for example based on acrylic polymer, polyurethane, polymethyl methacrylate, styrene butadiene, vinyl acetate, polyamide, nitrocellulose or any other cellulose, polyvinyl alcohol, starch, or a mixture thereof.

12. Method according to one of the preceding claims, characterized in that the multilayer structure (12 ') comprises at least one additional layer (34) deposited on the printable layer (18), on the opposite side to the plastic film (14), the free face of this extra layer or the additional layer furthest from the plastic film being intended to be glued and applied against the aforementioned face of the substrate during step b1.

13. Method according to one of the preceding claims, characterized in that it comprises an additional step of printing the sheet

(10) with an ink having electrical and / or optical properties.

14. Method according to one of the preceding claims, characterized in that the smooth face (22) of the sheet (10) has a Bekk smoothness greater than 900s about or greater than about 1000s, preferably greater than 2000s, and more preferably greater than 5000s.

15. Method according to one of the preceding claims, characterized in that the smooth face (22) of the sheet (10) has a gloss greater than 70%, and preferably greater than 80%.

16. Method according to one of the preceding claims, characterized in that the printable layer (18) has a thickness less than or equal to

30μηη, preferably less than or equal to 15μηη, and more preferably less than or equal to 10μηη, and / or a grammage less than or equal to 30g / m ² , preferably less than or equal to 15g / m ² , and more preferably less than or equal to at 10g / m ² .

17. Method according to one of the preceding claims, characterized in that it comprises, before step a /, a preliminary step of making, for example by etching, recessed patterns and / or relief on the face. plastic film for receiving the release layer and the printable layer, the printable layer being adapted to conform to the shape of these patterns so as to include a print of the aforementioned face of the plastic film.

18. Method according to one of the preceding claims, characterized in that the adhesive is deposited on at least one side of the substrate in step bl, and in that the thickness of the deposited adhesive layer is at least equal to half of the average roughness of the face of the substrate, and is preferably equal to this average roughness.

19. Printable sheet (10) having at least one smooth face (22), said sheet comprising a substrate (24), in particular of paper, at least one side of which is covered at least in part with one or more layers superposed, including a printable layer (18) defining said smooth face, characterized in that said smooth face has a Bekk smoothness greater than 900s or greater than 1000s, preferably greater than 2000s, and more preferably greater than 5000s.

20. Printable sheet according to claim 19, characterized in that its smooth face (22) has a gloss greater than 70%, and preferably greater than 80%.

21. Printable sheet according to claim 19 or 20, characterized in that the printable layer (18) has a thickness less than or equal to 30μηη, preferably less than or equal to 15μηη, and more preferably less than or equal to 10μηη, and / or a basis weight less than or equal to 30 g / m ² , preferably less than or equal to 15 g / m ² , and more preferably less than or equal to 10 g / m ² .

22. Use of a printable sheet according to one of claims 19 to 21, for the production of an electronic and / or optical component, this sheet being printed with an ink having electrical and / or optical properties.

23. Use of a printable sheet according to one of claims 19 to 21, for printing a photographic image, for producing a package, and / or for a casting application.