FR2879225A1 - GLOSSY PAPER - Google Patents

Abstract

The present invention relates to a glossy paper having a roughness greater than 30 ml / min measured according to ISO 8791-2, manufactured completely on a paper machine, and characterized in that it comprises microplates or microbeads reflective of dimensions less than 300 mu integrating at least one optically transparent material in their structure.

Description

The invention relates to the field of glossy papers that can be used for

  production of magazines, brochures or advertising material.

  Glossy papers are generally obtained by means of a calendering or supercalendering operation of coated papers with an essentially inorganic coating, said calendering operation makes it possible to smooth the surface thoroughly.

  The gloss is obtained on the coated and calendered paper by the uniform reflection of the light on the extremely smooth and homogeneous surface.

  This procedure has been known for many years as well as the constraints inherent in this type of manufacture, some of the known drawbacks of which are given below: the paper must be coated or contain a very high load rate so that the operation calendering physics is effective, which requires an expensive operation if it is performed outside the paper production line, or an economically unfavorable operation if it is performed on the machine because of the productivity losses generated by the treatment device. Such coated paper has significantly lower physical characteristics compared to uncoated paper, especially with regard to stiffness, burst strength, etc.

  The paper must be calendered or supercalendered, that is, the surface is smoothed by a rolling operation. This operation also induces a loss of the mechanical characteristics of the paper and generates a paper of mineral touch, far removed from soft and pleasant papers such as those sold in the ranges of fine art papers or covers.

  A calendering operation as described above, must, to achieve a uniform gloss, be performed on a very homogeneous paper in both its surface appearance and its thickness to prevent the formation of a hammered appearance. Paper makers refer to the highest possible characteristic.

  In addition to the above problems the method does not in any way to obtain a textured paper or relief since the method consists in completely leveling the surface.

  Such embossed papers correspond, not only, to the papers of the categories printing and writing, texts and covers and fine arts, for which a particular paper texture is often sought. Paper texture must include papers with watermarks, particular colors, orchards, various markings such as those produced with grain markers or markers, etc ...

  Another means for producing glossy papers and more particularly said embossed papers is to coat a gloss varnish during a processing operation, out of the paper machine. The gloss is obtained by a high quantity deposit of a glossy polymer.

  A process similar to that of the varnishing can be performed on a coater with a formulation similar to that of a varnish.

  This way of proceeding with textured papers requires in all cases an additional operation and the application of a thick layer of a bright binder, which is not always technically feasible depending on the relief of the paper.

  This type of coating or coating treatment has been known for a long time and the disadvantages of overcost also.

  Another technique is to laminate the finished paper with a polymer film.

  The laminating operation carried out outside the paper machine, when the paper is manufactured, is also expensive and corresponds to an application different from that of the invention, rather from the field of the transformation of the printed paper than that of the production. .

  The colored papers present on the market are rarely sold with a brilliant effect because the fact of bedding these papers modifies the color and leads to heterogeneous effects little sellers, the varnishing which implies an additional operation leads to an unacceptable extra cost, moreover the machines manufacturing these papers do not generally have a coating tool on the production line and are therefore generally not able to achieve a glossy layer removal in the same operation as that of paper making, in fact these papers are very not widespread. There is therefore a need for the manufacture of glossy colored papers, textured or not, which can be manufactured economically.

  The invention therefore aims to solve these major difficulties, that is to say manufacture a glossy paper economically without calendering or varnishing operation on all paper machines, with or without built-in coater, and with all the feasible supports, in particular colored or textured.

  The glossy paper according to the invention has a roughness greater than 30 ml / min measured according to the ISO 8791-2 standard, it is manufactured completely on a paper machine, and it is characterized by the fact that it comprises microplates or reflective microspheres of dimensions less than 300 p integrating at least one optically transparent material in their structure.

  The advantages of the paper according to the invention are both economic, since it is possible to manufacture a glossy paper without calendering, coating or processing, and at the same time technical because glossy papers as proposed allow to obtain particular optical effects and in particular a remarkable gloss on textured or colored papers with full maintenance of the mechanical characteristics of the paper, in particular with regard to rigidity and resistance to bursting.

  Another remarkable effect of the invention, not produced by calendered coated papers or known lacquer papers, is that the optical rendering of the paper according to the invention is variable according to the ambient lighting at the moment of observation. When lighting is important, in the sense of the light reaching the paper, the treatment leads to a uniform gloss effect whereas when the lighting is low scintillated individual points are perceptible on the surface of said paper.

  Another advantage provided by the treatment composition is that the glossy treated paper retains all its physical and mechanical characteristics as well as its appearance and touch characteristics, which is decisive in the case of textured papers for which relief is desired and for which it is often required a pleasant touch, this is more particularly the case for papers incorporating cotton linters in their fibrous composition. Coating, coating or varnishing treatments result in the loss of these appearance properties which are particularly appreciated for fine art papers and most papers used in printing and writing.

  Given the advantages mentioned above and the fact that the treatment is applicable on a large number of different media many new products, nonexistent on the market, are feasible and including but not limited to: É Glossy colored textured papers.

  É Glossy embossed papers suitable for enhanced quality inkjet printing according to the teachings of the patent application FR 0313700.

  É Glossy watermark papers suitable for enhanced quality inkjet printing according to the teachings of the patent application FR 0313700, for example papers usable in letterheads, mailings, or even as security papers.

  É Shiny art papers, such as watercolor, drawing, pastel, etc ... papers with the usual qualities of contexture and touch.

  Other features and advantages of the invention will become apparent from the following description and non-limiting examples provided.

  In this description and in the sense of the invention it must be understood by coated paper any paper having on its surface a coating comprising at least one polymeric binder and optionally inorganic or organic fillers, the operation being carried out on or off the machine. using a coating tool to maintain the layer deposited on the surface of the paper, that is to say that said layer does not penetrate more than 20%, and generally less than 10% of the paper thickness.

  Uncoated paper is to be understood as a raw paper having either no surface treatment or impregnation or coating by means of various, preferably rolled, devices which force the penetration of the treating composition into the entire sheet thickness or at least 30% of said thickness.

  Within the meaning of this description, a varnished paper is a paper on which is deposited a glossy transparent layer, penetrating very little into the paper, that is to say in less than 20% of its thickness, generally consisting essentially of a glossy polymer without additional charge and with a solids content of at least 2 g / m 2 and preferably more than 5 g / m 2. The varnishing operation being performed outside the paper machine on a specific material, a coating machine, or by means of a coating apparatus.

  The gloss of the paper within the meaning of the invention is defined by the visual effect produced at observation at a variable angle between 20 and 80. Depending on the quantity and the nature of the treatment composition applied, the optical effect produced is situated between a scintillating effect, such as that produced by snow in the sun for example, that is to say bright spots distributed randomly. reflecting light, and between a uniform glossy effect without individualized glittering dots.

  The optical effects obtained in the invention are not only variable according to the angle of observation of the treated paper but also according to the ambient lighting, the visual effect is changing depending on the lighting is low, in these conditions glittering points individualized are more particularly visible, or strong, and in these conditions the brilliant effect is homogeneous and very intense. These effects are very different from those obtained in coated calendered papers or varnished papers which never have a scintillating appearance and whose gloss is relatively independent of the lighting conditions.

  The roughness of the paper is usually measured by means of different devices such as Bekk, Bendtsen or Sheffield devices, said roughness measurement is standardized and reference is made here more particularly to the ISO8791-2 standard for expressing the roughness of the paper. in ml / min with the Bendtsen device. The papers according to the invention have a roughness of at least 30 ml / min and preferably more than 100 ml / min which in the traditional classification of papermakers corresponds to raw papers or very slightly calendered but in no way to papers traditional glosses whose roughness values measured in Bendtsen are at values below 30 ml / min and more generally below 10 ml / min.

  The textured papers for which the treatment is of particular interest have roughnesses greater than 300 mpm and generally above 1000 ml / min when texturing using marker pens or engraved presses is employed.

  The treatment composition according to the invention is applicable to all types of paper, textured or colored in particular, by means of a tool arranged inside the paper machine, preferably a gluing press, a multiple roller device known as "gate roll" or "massey", an impregnator, a roller device having pre-dosages for the coating formulation such as for example that called "blade metering size press" ("BMSP"), or any other device comprising at least one roll in contact with the paper.

  Traditional coating tools arranged inside the paper machine can be used, such as for example towing or barbed coatings.

  The treatment composition according to the invention employs reflective particles in the form of platelets or microbeads incorporating in their structure at least one optically transparent material, in general a compound classified in the general family of glasses, for example a borosilicate.

  The dimensions of the particles, that is to say their greatest length in the case of microplates or the diameter in the case of microbeads, are less than 300 μ and preferably between 50 and 250 μ so that the reflective effect is optimal. Too fine particles, that is to say the size of the usual coating pigments, typically less than 30 p, penetrate too much into the paper support during the application of the treatment composition and their gloss effect is found very attenuated.

  The reflective effect of the platelets or balls is created by the combination of an optically transparent material and a light reflecting material, the manufacture of such particles in the form of platelets or beads is known per se and carried out in particular by Merck, which has developed technologies to obtain particles with different materials in successive layers.

  The products used in the context of the invention are remarkable in that they can be used in extremely reduced doses on all types of supports and more particularly on supports of notable roughness as defined above, and in the fact that they are applicable by conventional means present on all paper machines and not only sleeping tools.

  Preferably, according to the invention, the roughness of the finished paper is greater than 100 ml / min according to ISO 8791-2 and the microplates or reflective microbeads are incorporated at least 0.5% and preferably at least 0.5%. 0.15% by dry weight compared to the finished paper.

  The treatment composition according to the invention comprises at least one class of particles in the form of microplates or reflective microbeads incorporating at least one optically transparent material in their structure, and at least one binder for fixing said particles in and on the surface of the paper. Reflective microplates of dimensions between 20 and 200 μ, quite suitable are for example marketed by Merck under the name MIRAVAL and under the reference 5411 Magic White.

  The binder can be conventionally a starch, a polyvinyl alcohol, a latex or any other polymer that can be used in a known manner in paper industry. The amount and nature of said binder is selected depending on the coating means employed and factors related to the subsequent use of the paper such as, for example, the printing medium employed.

  Preferably it is used at least one binder bringing bright and optically transparent not to degrade the effect obtained with the particles incorporated. Such binders that can enhance the gloss of the reflective particles are, for example, and without limitation, the polymers selected from the families of polyvinyl alcohols, acrylic latices, polyvinylipyrrolidones.

  According to the invention, the glossy paper which comprises microplates or reflecting microbeads in a proportion of at least 0.05% by dry weight relative to the paper, and preferably at least 0.15%, also contains a polymeric binder at a rate of less than 0.1% by dry weight and preferably more than 1% by weight of paper.

  In order to retain the microplates or reflective microbeads in the paper the level of binder inside the treatment composition must be sufficiently high, it has been found particularly advantageous to put at least the same amount of binder, in dry weight. incorporated, as reflective particles, and preferably at least twice as much.

  The invention also relates to the process for obtaining a gloss paper with a roughness greater than 30 ml / min measured according to ISO 8791-2, manufactured on a single-stage paper machine, and characterized by the succession of phases. following: realization of a paper support, coating on said support of a treatment composition comprising microplates or reflective microspheres of dimensions less than 300 p integrating at least one optically transparent material in their structure, and comprising at least one polymeric binder in a dry amount at least equal to that of said microplates or said microbeads.

  Drying said composition and winding the finished paper.

  Preferably the process is characterized in that the paper support can be colored, textured, watermarked, laid, marked with markers, engraved presses or any other device known to give a relief or heterogeneity to the paper by any method to inside the paper machine, before the treatment formulation is applied to its surface.

  The process for obtaining a glossy paper is also characterized in that the microplates or reflective microbeads are incorporated in the paper together with the polymeric binder in a treatment composition applied by means of a coating device comprising at least a roll, conventionally a gluing press.

  The process is particularly well suited for obtaining bright colored papers without calendering or coating operations.

EXAMPLE 1

  According to an advantageous embodiment of the invention, a treatment composition comprising reflective microplates incorporating at least one optically transparent material in their structure is applied to the size press on a paper of 150 g / m2 textured by marker pens.

  The treatment composition consists of a solution comprising, by weight relative to the total weight of the formulation: 2% of a polyvinyl alcohol of high viscosity, Mowiol 28-99 marketed by the company SEPPIC and 0.5% of MIRAVAL 5411 Magic White from Merck.

  The carrier of the preceding solution to the sizing press is 35% by weight relative to the paper, which represents a weight of reflective microplates incorporated in the paper of 0.175% and a weight of polymeric binder of 0.7%. Said binder is in quantity four times greater than the amount of reflective microplates in the composition.

  The brilliant effect obtained is variable depending on the lighting conditions. When the paper is observed in the sun or near a lamp the gloss effect is homogeneous and very intense. When the paper is observed in a poorly lit place it appears essentially sparkling points.

  The glossy white paper thus obtained has a roughness measured according to the ISO 8791-2 standard of 1500 ml / min.

  The mechanical characteristics of such a paper, especially its rigidity and burst strength, are identical to those of a bright untreated paper.

EXAMPLE 2

  In another example, glossy and laid colored paper is obtained by making a colored paper of 100 g / m2 laid on the table of the paper machine and mass-colored in a conventional manner.

  The colored and textured sheet is coated with the size-sizing press with a composition comprising, by weight relative to the total weight of the formulation: 1% of a polyvinyl alcohol of high viscosity, Mowiol 28-99 marketed by the company SEPPIC, 5% by weight. dry weight of a DL 955 styrene butadiene latex marketed by the company DOW CHEMICAL and 2% of MIRAVAL 5411 Magic White from Merck.

  The treatment composition penetrates the entire thickness of the paper and a load of 40% is found. In fact, the reflective microplates are incorporated at a rate of 0.8% by dry weight relative to the weight of paper, the polymeric binder represented by the polyvinyl alcohol and the latex is incorporated at the rate of three times the amount of reflective microplates and at a rate of 2.4% based on the weight of paper.

  The finished paper still has its original color and texture before treatment, the roughness is measured at 1000 ml / min, the gloss of the paper is very strong under a lot of light, producing a particular optical rendering but with the classic characteristics touch and relief provided by the shepherds.

  The mechanical characteristics of such a paper, in particular its rigidity and its resistance to bursting, are identical to those of a non-treated glossy paper.

EXAMPLE 3

  Glossy paper, Bendtsen roughness measured at 800 ml / min, suitable for inkjet printing of enhanced quality as defined in the application FR 0313700, comprising: É A 250 g / m2 textured white backing paper is produced by the manufacture of a base containing a fibrous composition of 100% by weight of cotton, in which is inserted, by weight with respect to the 15% fibers of TIXOLEX 28 from RHODIA, 1% by weight of cationic starch, 3% of commercial product of AQUAPEL 305 gluing agent from the company HERCULES and 3% of calcium carbonate used as an additional filler. The previous composition is deposited on the canvas of a round shape of a paper machine, pressed with a device of engraved presses to give the texture of a watercolor paper and then dried in the usual way until the end of pre-drying where is coated a sizing press treatment composition.

  A treatment composition comprising, by weight, commercial products relative to the total weight of solution: 6% of cationic PVA CM 318 from KURARAY, 10% of TIXOSIL 365SP with 22% dry matter from RHODIA and 3% of Reflective microplates MIRAVAL 5411 Magic White from Merck.

  The previous solution is applied by means of a gluing press on the base paper in a proportion of at least 30 liters of treatment composition per 100 kg of paper, which taking into account this paper represents approximately 30% of the thickness treated. and a hydrophilic binder amount of 1.8% based on the weight of paper. Reflective microplates are incorporated at a rate of 0.9% dry product over finished paper.

  The paper thus coated is dried post-drying and the finished product is wound without calendering so as to preserve the texture formed with the engraved presses. The product has the texture of watercolor paper with high gloss and high printability.

  The mechanical characteristics of such a paper, in particular its rigidity and its resistance to bursting, are identical to those of a non-treated glossy paper.

  Such paper can be used for art reproduction on large format inkjet printers or as a support for photo printing in desktop printers. There is no equivalent on the market of such paper that is both textured, glossy and ink-jet-ready, even if produced by a different technique.

  In the process claimed the fibers used to make the paper may be cellulosic and / or cotton linters, wholly or partly, in association or not with synthetic fibers or fibers of other kinds. All additives traditionally used in paper industry such as additional fillers (talc, kaolin, calcium carbonate, etc.), bonding agents, retention agents, colorants, brighteners, etc. can be used without departing from the scope of the invention.

  The texture of the product may be strong or non-existent, the paper may be watermarked or not, high or low weight, without departing from the scope of the invention which is to bring a gloss effect to non-calendered and unvarnished papers while retaining their usual appearance properties including roughness and touch.

  In addition to those already mentioned, one of the advantages of the invention is that it is possible to produce a paper treated differently on its two sides, directly in the paper making process, and thus to obtain finally a paper having two different glosses on its two sides. faces, which represents a strong commercial advantage. For example a paper marked with a marker pen on one side, and a smooth surface on the back, or more sophisticated two different textures on both sides by combinations of different marker pens and / or engraved presses associated with an identical treatment on both sides to the gluing press.

  It is also conceivable to obtain different optical effects on both sides by means of a symmetrical support paper coated differently on these two sides, for example by combining a gluing press and one-sided coating on the paper machine, or a gluing press treatment with different solutions on both sides. A wide variety of products is thus feasible.

  According to the invention, it is possible to process all types of paper media, which means that very specific papers such as those intended to give the paper an ink-jet capability are included, and in particular the products resulting from the techniques described in FIG. unpublished application FR 0313700 of the applicant. According to the combination of the two inventions it is possible to obtain an inkjet paper of enhanced quality, and moreover bright, directly on a paper machine. The paper tests combining the teachings of the application FR 0313700 and of the present invention show that a glossy paper of enhanced inkjet quality is achievable and that this paper leads to an impression whose printed part appears to the observer as Metallic this effect is quite new and remarkable, especially if a textured backing is used.

  Several variants are also possible for the treatment composition to obtain a glossy paper, it may in particular be added various additives such as co-binders, rheology modifiers, defoamers, antifungals, optical brighteners, dyes and various other compounds traditionally known in paper making without departing from the scope of the invention.

  Various means of application of the treatment composition are conceivable to give various effects, it may for example be imagined to treat only a portion of the paper sheet to make glossy strips neighboring with strips of raw paper, alternately. It may also be envisaged to apply the spray treatment composition or any other coating means, conventional or otherwise, inside the paper machine, without departing from the scope of the invention.

  Of course, the invention is not limited to the embodiments described and shown by way of example, but it also includes all the technical equivalents as well as their combinations.

Claims (1)

12 CLAIMS   1-glossy paper of roughness greater than 30 ml / min measured according to ISO 8791-2, manufactured completely on a paper machine, characterized in that it comprises microplates or microbeads reflective dimensions of less than 300 p integrating the less an optically transparent material in their structure.   2- glossy paper according to claim 1 wherein the roughness is greater than 100 ml / min according to ISO 8791-2 and the microplates or reflective microbeads are incorporated at a rate of at least 0.05% by dry weight and preferably at at least 0.15% compared to the finished paper.   3- glossy paper according to claim 1 obtained by coating a treatment composition containing microplates or reflective microbeads and at least one polymeric binder, which treatment composition allows the incorporation of said microplates or microbeads at a rate of less than 0.05% by dry weight and preferably at least 0.15% with respect to the finished paper, as well as said polymeric binder in a proportion of at least 0.1% by dry weight and preferably more than 1% with respect to the weight of paper.   4- Glossy paper according to claim 3 obtained by coating a treatment composition comprising a weight of dry binder at least equal to the weight of microplates or reflective microbeads.   5. Glossy paper according to claim 4 wherein the binder employed is selected from the family of polyvinyl alcohols, acrylic latices or polyvinylpyrrolidones.   6. Glossy paper according to claim 3 wherein the treatment composition is coated by means of a material having at least one roller, for example type gluing press, "massey", "gate-roll", "BMSP".   7- Glossy paper according to claim 3 characterized in that it can be colored, textured, watermarked, laid, marked with felts, engraved presses, to give a relief or heterogeneity to the paper inside the machine before the treatment formulation is applied to its surface.   8. A process for obtaining a glossy paper with a roughness greater than 35 ml / min measured according to ISO 8791-2, manufactured on a single-stage paper machine, characterized by the succession of the following phases: of a paper support, coating said support with a treatment composition comprising microplates or reflective microspheres of dimensions less than 300 μ integrating at least one optically transparent material into their structure, and comprising at least one polymeric binder in quantity drying at least equal to that of said microplates or said microbeads, drying of said composition and winding of the finished paper.   9- A process for obtaining a glossy paper according to claim 8 characterized in that the support can be colored, textured, watermarked, laid, marked with markers, engraved presses, to give relief or heterogeneity to the paper inside the paper machine, before the treatment formulation is applied to its surface.   10- A process for obtaining a glossy paper according to claim 8, characterized in that the treatment composition is applied by means of a coating device comprising at least one roller, for example of the "Massey" sizing press type, "gate-roll", "BMSP", for incorporating into the paper an amount at least equal to 0.05% by dry weight and preferably at least 0.15% of said microplates or microbeads with respect to the finished paper, as well as less than a polymeric binder in a proportion of at least 0.5% by dry weight and preferably more than 1% by weight of paper.