FR2868731A1 - PROCESS FOR MANUFACTURING MULTIPLE FIBROUS CELLULOSIC PRODUCT - Google Patents

Abstract

To produce a multi-layer cellulose fiber web, for use as table napkins or handkerchiefs, at least one web layer (201) is embossed between an embossing (210) and a pressure (212) roller, and a glue is applied to the embossed relief peaks in the layer as it is carried by the embossing roller through a glue stattion(214) where a roller (214') transfers the glue. A second layer (202) is applied to the glued embossed peaks. A third layer (203) is glued (216) and applied by a structured roller (215) with a further embossing pattern, to be carried through a gap between the embossing roller and a further press roller (218) which bonds the layers together with an embossed pattern.

Description

The invention relates to the field of products in cellulose wadding for use

  sanitary or domestic and is particularly aimed at products cut into formats such as napkins or tissues.

  Cellulose wadding, also referred to as tissue paper in the field, is a lightweight and absorbent material that has been developed for the above mentioned applications. It enhances the qualities of softness or wet or dry resistance according to the particular use for which it is intended. For example, for a tissue paper, priority is given to softness because it comes into contact with the skin, especially the nose which is very sensitive. In the case of a napkin, it favors the textile touch and a certain stiffness to imitate the drape of textile towels. In order to be able to combine several qualities, it is necessary to combine several plies of cellulose wadding of low grammage, embossed or not, each having different properties or not.

  The Applicant has developed a napkin or tissue product consisting of several plies of cellulose wadding assembled by edge gluing along its periphery. This product is covered by patent EP 670 773. A method of manufacturing this product with three or four plies is shown in FIG. 1. The machine is composed of a cylinder engraved according to the pattern forming the peripheral zone of the product; the pattern is composed for example of pins regularly distributed along strips arranged so as to search a frame. Preferably, the etching pattern corresponds to several products juxtaposed as described in patent EP 0893242. The cylinder 10 cooperates with a pressure cylinder 12 of parallel axis, rubber or other equivalent material, to emboss a first sheet of tissue paper 100 that is engaged between the two. In Figure 1, there is shown a sheet 100 with two superposed folds. The double sheet is driven onto the cylinder 10 against the etching of which it is applied by the cylinder 12. Glue, preferably water-based, such as a polyvinyl glue, is deposited on the raised surfaces of the etching by means of The gluing device shown comprises a cylinder communicating with a doctor chamber in which it takes a metered quantity of glue, and an applicator cylinder on which it deposits the glue. The applicator roll deposits the glue on the surface elements in relief of the sheet 100, against which it is supported.

  The cylinder 10 cooperates with a second pressure cylinder 16, said marrying cylinder, to ensure the connection of the first sheet 100 with a second sheet (or strip) of tissue paper 110. The still wet glue on the raised parts of the first The sheet or strip of tissue paper 100 is transferred in part onto the inner face of the second sheet which is brought into contact with the first sheet at the marrying roll. The pressure exerted by the marrying cylinder 16 on the two strips of paper ensures the formation of a bond. According to whether it is desired to produce a product with three or four plies, the second strip 110 is at one or two plies.

  To make a tissue paper eg 60g / m2, it is preferred to combine four plies of light weight 15g / m2 rather than three plies of 20g / m2. This combines good resistance in use and softness to the touch. However, it is noted that the delamination resistance, in particular that of the outer ply corresponding to the second ply of the strip 110 above, is not satisfactory for the products with four plies.

  It is also noted that this method of gluing does not make it easy to dose the amount of glue to be applied for the formation of the connection so as to provide an amount just sufficient to bind the plies between them without too much stiffen the handkerchief.

  It is thus necessary to maintain the specific pressure exerted by the second pressure cylinder at a high level. This presents not only a problem on the industrial level but also on the quality of the product; indeed, by strongly embossing the sheet by the second cylinder, a product is obtained which has a softer reverse.

  The Applicant has also obtained a patent, EP 567 604, on a method of embossing cellulose sheets with two or more plies in which the printing of one of the plies is performed directly on the embossing cylinder. by means of one or more printing units installed on the embossing units and this fold is associated with another embossed and embossed fold to form a sheet so that the printing pigments are on the inner face of the embossing unit. sheet between the two or more folds. FIG. 2 reproduces one of the figures of patent EP 567 604. A fold of tissue paper 101 moves from a mother reel passing around a rubber pressure cylinder 102 and is then applied and embossed on a first embossing cylinder 104. The fold is glued by a sizing group 105. A second fold of tissue paper 107 moves around a pressure roll 110, and is embossed on a second embossing roll 112 of steel or other equivalent material. A printing unit 113 (containing pigments) prints the tissue paper 107 at the second embossing roll 112. The two folds 101 and 107 are then assembled by passing together between the first embossing roll 104 and a match roll 117. The assembly here is of nested type, that is to say that the protuberances formed on the fold 101 fit between the protuberances formed on the fold 107. The advantage of the solution disclosed in this patent is to confine the pigments between both folds and synchronize the print pattern with the emboss pattern. 1.5

  The Applicant has also developed a method of manufacturing products in format having a peripheral edge and a printing pattern. According to this method, as described in patent EP 684 132, glue is applied to a first ply along a defined gluing pattern to form a seal along the edge of the product, a second ply of paper is applied on the first side so as to form a partial connection, the assembly is directed to a printing station where it is printed on one of its surfaces and the connection is completed by an embossing step. This process makes it possible to produce products of good print quality thanks to the prior binding of the folds to one another, but it does not make it possible to print folds separately.

  The applicant has set as its goal the production of cut products in tissues of the type handkerchief or towel of at least three folds, combining the advantages of a good combination of plies and decoration patterns that can be varied, and possibly colored differently on both sides of the products.

  This objective is achieved according to the invention with a process for manufacturing a cellulosic product multiplia cut into format, comprising the steps according to which: at least one ply of fibrous cellulosic material is applied to a cylinder having reliefs and it is embossed on the cylinder by means of a first pressure cylinder, - glue is deposited on first raised areas formed on the fold, 5 - at least one second fold is applied to the first fold, characterized by the it also includes the steps according to which - a third fold is caused around a second cylinder - glue is deposited on the third fold - the third fold is applied to the second fold - and the three plies by means of a second pressure cylinder bearing against the first embossing cylinder.

  The invention has the double advantage sought. It makes it possible to associate the last fold with the others effectively by the second glue, while allowing, by the pattern of the second cylinder, to bring an additional decoration on the rear face of the final product. The advantages induced by the process are also to obtain a product whose backside is smooth because it is not necessary to exert significant pressure by the second pressure cylinder.

  Moreover, the product remains flexible despite a deposit of glue on a large surface of the product.

  Advantageously, the second cylinder may be etched according to a second etching pattern.

  According to a first embodiment of the method, the glue is deposited on the third fold by means of an applicator roll, without prior embossing of the fold on the second roll. This solution keeps the third fold its initial thickness and softness.

  According to a second embodiment, the glue is deposited on the third fold by means of an applicator roll the sheet having been previously embossed on the second roll. This solution allows to vary the patterns in case some would not be printed satisfactorily without embossing. Preferably in this case, it proceeds in such a way that the embossing leads to the formation of protuberances on the third fold of low height, in particular less than 0.1 mm.

  According to another feature, the first cylinder is engraved in a pattern representing the periphery of a product cut into the format.

  According to another characteristic, at least the glue applied to the third fold is colored. Thus, the pattern corresponding to the glued surface is clearly visible on the finished product.

  According to one characteristic, the second pressure cylinder has a hardness greater than that of the first cylinder.

  A preferred, but not limitative, embodiment of the invention is described below with reference to the drawings, in which: FIG. 1 represents an installation according to the prior art for producing products cut into the format, with gluing 2 shows an installation as described in patent EP 567604 for printing products with at least two plies and embossed, Figure 3 shows an installation for implementing a method according to the invention. 4 represents a product obtained according to the invention.

  Referring to Figure 3, we see an installation that allows the assembly of cellulose wadding, for example of basis weight between 12 and 40 g / m2, into a multi-ply continuous sheet. After assembly, this sheet is then guided to another post where it can be cut into formats, and transformed into napkins or tissues.

  A first sheet (or ply) 201 of cellulose wadding, single or double, is guided from a reel not shown, to an embossing unit comprising a first engraved cylinder 210 and a first pressure cylinder 212 of rubber or other material with the appropriate hardness. The sheet is embossed by passing through the nip between the two cylinders 210 and 212. The sheet is pressed against the first cylinder 210 which it matches the relief. For the manufacture of products such as tissues or napkins, the engraving on the first cylinder 210 forms, for example, strips arranged in a square or rectangle in the manner of frames of a given width, as reported in the patent. of the Applicant EP 684132.

  Downstream of the first pressure cylinder 212, a sizing unit 214 comprising an applicator roll 214 'deposits glue, preferably water based such as a polyvinyl glue, on the raised parts of the sheet pressed against the cylinder. 210 and whose form she marries. By continuing its rotation, the cylinder then brings the sheet 201 to an area where it is approached i 0 by a second sheet (or fold) 202, fed from a second reel for example of tissue paper. The sheet 202 is itself accosted by a third sheet 203 of tissue paper, on its other side. This sheet 203 is also derived from a mother reel not shown. The third sheet 203 is guided around a second cylinder 215 whose axis is coplanar with that of the first engraved cylinder 210, and having on the surface a printing pattern type pattern. The second cylinder 215 preferably does not exert pressure on the first cylinder 210. The third sheet 203, preferably a single ply, is glued by a second gluing unit 216 when in contact with the cylinder 215 In FIG. 3, it can be seen that the sheet 203 is not subjected to the pressure of a pressure cylinder before it passes between the second gluing unit 216 and the second engraving cylinder 215.

  The pressure exerted by the non-referenced gluing roll of the second gluing unit 216 is sufficient to transfer the glue to the portions of the third sheet 203 supported by the engraved print pattern on the second cylinder 215.

  The glue can be advantageously colored so that the pattern is visible on the finished product.

  The third sheet 203 accost the sheet 202 in the region forming the gap between the first (210) and second (215) cylinders. The three sheets 201, 202 and 203 thus superimposed are then subjected to the pressure of a marrying cylinder 218 disposed downstream, and the sheets are bonded together at this level.

  It is observed that the pattern engraved on the second cylinder 215 preferably comprises a zone which overlaps at least partially the engraved pattern on the first engraved cylinder 210 so that the glue provided by the second gluing unit 216 effectively participates in the binding of the third fold 203 on the second fold 202. The amount of glue provided by the glue 216 then need not be important; it suffices that it allows the connection of the second fold 202 to the third fold 203.

  It is also observed that in this case the marrying cylinder 218 no longer needs to exert a significant pressure on the plywood sheet because the glue does not have to cross the thickness of a fold to ensure the binding of the plies.

  Preferably the hardness of the marrying cylinder 218 is greater than that of the first pressure cylinder 212. As an illustration, the first embossing cylinder may have a hardness of 60 shore while that of the pressure cylinder of 55 shore.

  It is understood that this embodiment also makes it possible to easily vary the pattern printed by the second engraved cylinder 215. The technical constraints to make a so-called printing cylinder are much less than those required for the production of an embossing cylinder. In addition, it is much freer to the extent that it does not fulfill any technical function related in particular to the softness, the thickness or the breaking strength of the sheet.

  Furthermore, without departing from the scope of the invention, the second cylinder 215 may be smooth. It then cooperates with a cylinder of the gluing unit 216 which itself has a raised pattern.

  Note however that for some reasons, it may be necessary to mark the sheet with the pattern beforehand to allow a clearer transfer of glue on the sheet. In this case, the application of a slight embossing pressure upstream of the passage under the glue will be sufficient. According to this variant of the invention, a pressure cylinder (not shown) may be provided in order to perform an embossing upstream of the gluing of the third sheet 203. For example, the height of the protuberances formed by the pattern will be less than 0.1 mm.

  To illustrate the possibilities offered by the method, there is shown in Figure 4, an example of cut products according to the invention with a first common face A and a rear face whose decorations are different. For example, four different decors B1, B2, B3, B4 have been represented, these four decors being able to be made in different colors B '1, B'2, B'3 and B'4.

Claims (10)

  A process for producing a multiply cellulosic fibrous product comprising the steps of: applying at least one ply (201) of fibrous cellulosic material to an embossing cylinder (210) having reliefs in a first pattern and the waffle on the cylinder (210) by means of a first pressure cylinder (212), - glue is deposited on first raised areas of the fold, - is applied at least a second fold (202) on the first fold, characterized by the fact that it also comprises the steps according to which: a third fold (203) is driven around a second roll (215), - glue is deposited on the third fold (203), and applied the third on the second fold (202) and - the three folds (201, 202, 203) are assembled by means of a second pressure cylinder (218) bearing against the first embossing cylinder (210).   2. The method of claim 1, wherein said second cylinder (215) is etched in a second pattern.   3. A method according to claim 1, wherein said second cylinder (215) is smooth and the glue is deposited on the third fold (203) by means of an applicator roll of a sizing unit (216) which presents a raised pattern.   4. Method according to any one of the preceding claims, wherein the adhesive is deposited on the third fold (203) by means of an applicator roll of a sizing unit (216) without prior crimping of the fold on the second cylinder (215).   5. Method according to any one of claims 1 to 3, wherein the adhesive is deposited on the third fold (203) by means of an applicator roll 35 of a sizing unit, the sheet having been previously embossed. on the second cylinder.   6. Method according to the preceding claim wherein the embossing on the third fold (203) leads to the formation of low protuberances, in particular less than 0.1 mm.   7. Method according to one of the preceding claims wherein the first cylinder (210) is etched in a pattern representing the periphery of a product cut to the format.   8. The method of claim 1, wherein at least the glue applied to the third fold (203) is colored.   9. Method according to one of the preceding claims wherein the second cylinder (218) has a greater hardness than the first pressure cylinder (212).   10. Process according to any one of the preceding claims, characterized in that the product is cut into formats.