EP0989227A2 - Process for treating flocks of a flocket support and the product obtained - Google Patents

Abstract

Flocks, already attached to the substrate, are lightly impregnated with polymer resin in aqueous emulsion in a bath. The material, thus impregnated, is dried. The resin attaches any loose flock fibers to the substrate. It limits ink penetration into the flock, in any subsequent printing stage. An Independent claim is included for the product of such manufacture. Preferred features: The resin content in the aqueous bath is preferably 2-12 dry wt%, especially 6-7%. Impregnation density is 100-150 g/m<2>. The resin is deposited in a moist environment on the flocked side only. Processes typically involve moistening, coating or atomization. Following impregnation, excess resin solution is wrung out using pressure rollers, which also even-out the deposit.

Description

The present invention relates to a method for processing the flocks of a flocked support, the support being any, for example paper, cardboard, plastic, textile or nonwoven. The invention relates to also the product obtained by this process, whether or not subsequently printed.

It is usual to decorate flocked supports, by printing on the flocks multicolored patterns or by marking the flocks by thermal application of a colored or metallized film, the latter method being generally known under the term "hot foil". The flocked supports are thus decorated in many areas, for example packaging and packaging, decoration, clothing, or wall covering.

The flocked supports can be decorated by screen printing, but such an impression does not allow precise reproduction of finely screened four-color patterns, because the screen printing frames used are limited by the dimensions of the mesh.

The flocked supports can also be decorated by printing heliographic, but this type of printing is also limited from the point of view of the quality and finesse of the graphic representation, and requires in addition, the prior production of specific printing tools, such as engraved cylinders, which are very expensive.

In addition, screen printing like heliographic printing require a large amount of ink to be deposited on the flocks, and this whatever the nature of the medium to be printed.

• contrairement au procédé d'impression sérigraphique ou héliographique, les machines d'impression offset ou flexographique sont sensibles aux flocks libres qui sont toujours plus ou moins présents sur un support flocké ; en effet, ces flocks libres quittent le support flocké lors de son passage à travers la machine d'impression et viennent se coincer dans des parties de la machine, telles que les cylindres d'entraínement et les plaques, ce qui détériore la qualité d'impression et nécessite des nettoyages fréquents, et donc des temps d'arrêts importants ;
• comme l'impression offset, flexographique ou par jet d'encre ne dépose que de faibles quantités d'encre sur le support à décorer, une quantité substantielle de ce dépôt d'encre peut être absorbée par les flocks du support flocké qui présentent, comme tout textile, un certain pouvoir d'absorption, ce qui réduit d'autant l'intensité des coloris imprimés et limite les possibilités de réalisation de coloris soutenus ou vifs.

We also know the offset or flexographic printing processes, but they can not be implemented in a simple way to decorate a flocked surface, for the following reasons:

• unlike the screen or heliographic printing process, offset or flexographic printing machines are sensitive to free flocks which are always more or less present on a flocked support; in fact, these free flocks leave the flocked support during its passage through the printing machine and get stuck in parts of the machine, such as the drive cylinders and the plates, which deteriorates the quality of printing and requires frequent cleaning, and therefore significant downtime;
• as offset, flexographic or inkjet printing deposits only small amounts of ink on the support to be decorated, a substantial amount of this ink deposit can be absorbed by the flocks of the flocked support which, as all textiles, a certain absorption power, which reduces the intensity of the printed colors accordingly and limits the possibilities of producing strong or lively colors.

The marking of a flocked support by thermal application of a colored film or metallic is also possible, under certain conditions. In such process, a colored or metallized layer is applied to a support temporary, usually a transparent polyester film, and then partially transferred to the flocks of the flocked support using a tool heater, such as a punch, which briefly presses said layer against the flocks of the flocked support, said layer then being transferred to the flocked parts of the support which have been overwritten by the punch. However, marking a flocked medium is more difficult than that of paper or cardboard, due to the textile and irregular nature flocked support, which requires specific conditions to be met of particular applications, namely the selection of a marking film to warm suitable for flocked support, and absolute compliance with the conditions of marking on a precise and very well adjusted machine. Even if these conditions are perfectly respected, marking very fine drawings or texts of very small dimensions cannot be done in good readability conditions or will be not very resistant to friction.

To make the flocked support easily printable by processes mentioned above, it is also possible to modify the flocked surface by crushing the flocks by calendering or graining with a heating cylinder, smooth or embossed, pressurized, but in this case the appearance and touch of the flocked support thus crushed are altered.

The object of the present invention is to propose a method for treating flocks of a flocked support, which allows to keep a soft touch and pleasant of the flocked support thus treated, which makes it possible to print the latter by conventional offset, flexographic, jet printing processes ink or by thermal marking using a colored or metallized film, under the usual conditions for implementing these processes, without special setting or use of special raw materials, while allowing precise reproduction of multicolored patterns, especially in four-color, with the quality of a photograph.

To this end, the invention relates to a method for processing the flocks of a flocked support, characterized in that it consists of impregnating with a weak quantity of polymer resin, in emulsion in an aqueous bath, the flocks of the flocked support and drying the flocked support thus impregnated, said resin being intended to fix to the support any flocks in the free state and to limit penetration, during a possible subsequent printing step, inks in the flocks.

Preferably, the resin content of the aqueous bath is advantageously between 2 and 12% by weight of dry matter, preferably between 6 and 7%.

In a particular embodiment, the method consists in impregnating the flocks of said emulsion with a density of between 100g / m ² and 150g / m ² .

According to another characteristic of the invention, the method consists in depositing the resin in a wet environment on the flocks, on the only side of the flocked surface of the support, by any process such as wetting, impregnation, coating or spraying. Advantageously, the method consists, after impregnating flocks with the resin in aqueous dispersion, wring out said flocked support thus impregnated between two pressure rollers to remove excess resin and standardize the resin deposit.

Advantageously, the resin is a synthetic polymer resin chosen among acrylic esters, synthetic latexes and polyester polyurethanes, so that the flocked support thus impregnated retains a soft, dry and non-sticky touch.

Preferably, the support is chosen from paper, cardboard, made of plastic, textile or nonwoven.

The invention also relates to the product obtained by the method as previously described, characterized in that it comprises a flocked support whose flocks are impregnated with dry resin whose density is between 2 and 12 g / m ² , preferably between 6 and 7g / m ² .

Advantageously, the flocks impregnated with resin of the above-mentioned product are printed with multicolored patterns, for example in four colors, with a offset, flexographic, inkjet or thermal application of a colored or metallized film.

We will now briefly describe the implementation of the method according to the invention.

The flocked support is manufactured by a process known per se, using classic textile fibers and an adhesive polymer resin to bind flocks to the chosen medium. Preferably, according to the invention, flocks of small dimensions, for example between 0.3 and 2mm, and the fibers are chosen among natural fibers, viscose-based rayon fibers, or cotton fibers, so that the support thus flocked has a soft touch and pleasant.

The flocked support is then impregnated with another polymer resin in emulsion in an aqueous bath, rather than in organic solution, in order to protect the environment.

The aqueous bath containing the resin in dispersion is deposited so uniform on the flocks of the flocked support, by any process, for example by wetting, impregnation, coating or spraying. Advantageously, the flocked support passes between two cylinders, including the applicator cylinder comprises a layer of foam impregnated with said emulsion for the place on the flocks of the flocked support. Then, the support flocked as well impregnated passes between two pressing rolls, for example one made of steel and the other in rubber, to remove the excess resin and standardize the resin deposit. In a way, it is a step of wringing the support impregnated flocked. The concentration of the impregnation bath is adjusted by so as to deposit a very small quantity of resin on the flocked supports, so as to maintain a soft and pleasant touch, but the amount of resin must be sufficient to allow subsequent printing, such as explained below.

After the impregnation step, the impregnated flocked support is dried by passage through a heat treatment oven, to evaporate the water contained in the treatment bath. Then, the product thus treated is rolled up and conditioned under conditions appropriate to the nature of the support. In in the case of paper or canon supports, the humidity level of the packaging must be close to the recovery rate of the supports. Finally, the product thus treated is cut into formats suitable for types desired impressions, or in the form of small rolls of dimensions adapted to different printing machines.

Alternatively, the treatment bath can be applied by coating in passing the flocked support between a cylinder and an applicator scraper.

It is important to note that thanks to the presence of the resin in the docks, the surface of the flocks is more regular, noticeably like paper or cardboard, which allows printing in the conditions usual of implementation, without particular adjustment. In particular, offset or flexographic or inkjet printing can be used work, because the presence of the resin in the docks limits the absorption of ink by the docks. In addition, there is no longer any risk of seeing the flocks at free state get stuck in parts of the printing machine because they are retained on the support by the resin.

Note also that it is better not to brush or a cleaning of the flocked support after its treatment by the process of the invention.

Although the invention has been described in connection with examples of particular achievements, it is quite obvious that it neither is in any way limited and that it includes all the technical equivalents of the means described thus as their combinations which these fall within the scope of the invention.

Claims (9)

Method for treating the flocks of a flocked support, characterized in that it consists in impregnating a small quantity of polymer resin, in emulsion in an aqueous bath, flock the flocked support and dry the flocked support thus impregnated, said resin being intended to fix to the supports any flocks in the free state and to limit penetration, when of a possible subsequent printing step, inks in the flocks. Process according to claim 1, characterized in that the content of resin of the aqueous bath is advantageously between 2 and 12% by weight of dry matter, preferably between 6 and 7%. Method according to claim 2, characterized in that it consists in impregnating the flocks of said emulsion with a density of between 100g / m ² and 150g / m ² . Method according to one of claims 1 to 3, characterized in that it consists of depositing the resin in a humid environment on the flocks, on the only side of the flocked surface of the support, by any process such as wetting, impregnation, coating or spraying. Method according to claim 4, characterized in that it consists, after impregnation of flocks with the resin in aqueous dispersion, to wring said flocked support thus impregnated between two pressure cylinders to evacuate excess resin and standardize the resin deposit. Method according to one of claims 1 to 5, characterized in that the resin is a synthetic polymer resin chosen from acrylic esters, synthetic latexes and polyesters-polyurethanes, so that the flocked support thus impregnated retains a soft, dry and non-sticky feel. Method according to one of claims 1 to 6, characterized in that the support is chosen from paper, cardboard, plastic, textile or nonwoven. Product obtained by the method according to one of claims 1 to 7, characterized in that it comprises a flocked support whose flocks are impregnated with dry resin whose density is between 2 and 12 g / m ² , preferably between 6 and 7g / m ² . Product according to claim 8, characterized in that the flocks resin-impregnated with the above product are printed with patterns multicolored, for example in four colors, by a printing process offset, flexographic, inkjet or thermal film application colored or metallic.