Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/30—Multi-ply
  • D21H27/32—Multi-ply with materials applied between the sheets
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/44—Watermarking devices
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
  • D21F11/06—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the cylinder type
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
  • D21F11/06—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the cylinder type
  • D21F11/08—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the cylinder type paper or board consisting of two or more layers
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
  • D21H21/42—Ribbons or strips

Definitions

• Sheet of fibrous material comprising a window and method of production
• the present invention relates to a sheet of fibrous material comprising a window and a method of producing this sheet.
• This arrangement allows to interleave the ribbon edge to a width that can reach 4 mm but this is still insufficient to ensure satisfactory resistance of the fixing of the ribbon along its edge.
• it is provided in the aforementioned document to form on at least a portion of the ribbon a layer of complementary fibrous material which comes to bridge the leaf portions extending on either side of the transparent tape.
• this complementary layer is applied on one side of the transparent ribbon so that even if it is made with perforations, there is a risk of delamination of the complementary layer and therefore of deterioration of the sheet along one of the ribbon edges. In practice, it is therefore not possible to use this technique to make a large window in a sheet of fibrous material.
• the film segments being connected to each other by sections of tape which are in one piece with the film segments and which have a width allowing a direct deposition of fibers on the ribbon sections, and - ensuring the formation of a second fibrous layer portion until the ribbon sections are trapped in the fibrous layer.
• An object of the invention is to provide a sheet of fibrous material having a large transparent window.
• the invention proposes a sheet of fibrous material having a window formed by a film segment having an edge forming a closed contour trapped in the fibrous material all along the closed contour in wherein the film segment has a serrated edge.
• the film segment is firmly held in the fibrous material irrespective of the direction of the forces to which it is subjected.
• the fibrous material surrounding the film segment has a structure with a high resistance to forces, so that the film segment is weakly solicited during handling of the fibrous sheet.
• the serrated edge comprises ribbon sections extending from a central portion of the film segment in one piece therewith, the ribbon sections having a width which is smaller than at the central portion of the film segment and being totally trapped in the fibrous material at least along the edge of the film segment.
• the ribbon sections constitute anchor lines of the film segment so that the attachment of the film segment is enhanced.
• this relates to a process for producing a sheet of fibrous material comprising windows, this method comprising the steps of:
• the method comprises the steps of forming two jets of fibrous material each having openings and joining the jets by trapping the edges of film segments having a serrated closed contour having dimensions larger than the openings.
• FIG. 1 is a diagrammatic sectional view illustrating a first embodiment of the method according to the invention
• FIG. 2 is a partial perspective view of an embodiment of the mask of a first embodiment. of the movie segment
• FIG. 3 is a sectional view along the line III - III of FIG. 2, after making the sheet of fibrous material,
• FIG. 4 is a sectional view similar to that of FIG. 3 of an alternative embodiment
• - Figure 5 is a front view of a second embodiment of the film segment.
• - Figure 6 is a front view of a third embodiment of the film segment.
• FIGS. 1 and 2 are sectional views similar to that of Figure 1 illustrating a second embodiment of the method according to the invention.
• DETAILED DESCRIPTION OF THE INVENTION With reference to FIGS. 1 and 2, the process according to the invention uses, in a manner known per se, a porous form 1 partially immersed in a fiber bath 2 and driven in rotation while maintaining the liquid level at the interior of the form 1 at a level lower than that of the bath 2.
• the porous form 1 comprises relief masks 13 having a closed contour, here a star shape.
• the masks 13 are made in a manner known per se by stamping the web of the porous form 1.
• Segments of film 14 separated from each other and having dimensions greater than the dimensions of the masks 13 are brought by a support band 41 to be deposited on a mask 13 while it is still outside the bath. It will be noted in this connection that if the mask 13 is porous, the film segment 14 can be kept pressed onto the mask 13 by a slight maintained depression within the shape 1. If on the contrary the masks 13 are rendered sealed, for example by means of a varnish applied to the surface of the mask, the experiment shows that the film segments 14 are maintained applied to the masks 13 by surface tension forces resulting from the slight film of liquid remaining on the masks 13 during the rotation of the form 1, even when the masks 13 are outside the bath.
• the film segment 4 can also be held in place by an adhesive having a low tack or by a water-soluble adhesive.
• the film segments have a closed contour edge which according to the invention is a serrated edge.
• the serrated edge comprises sections of S-shaped ribbon 42 extending from the central portion. Tray 43 of oval shape in one piece with it.
• the ribbon sections 42 further include perforations 44 of sufficient size that fibers can engage the perforations 44 and entangle with fibers above and below them. sections of ribbon 42.
• the fibers are deposited on the porous part of the shape 1 surrounding the masks 13, firstly below the overflowing edge of the film segments 14 and then above them to form a layer 10 trapping ribbon sections 42 and the edge of central portion 43.
• the sheet of fibrous material obtained is taken up by a conveyor belt 44 which drives it to a finishing station.
• the sheet of fibrous material has windows defined by openings 16 on the side of the masks 13 and openings 17 on the opposite side to the masks 13.
• the central portion 43 of the film segments 14 slightly overflows the masks 13, so that the openings 16 and 17 have the same dimension and are centered relative to each other.
• the windows appear in the same star shape both in reflection and transparency, regardless of the side of the sheet being examined.
• the central portion 43 of the film segments 14 overflows very largely with the star-shaped contour of the masks 13, for example of the order of 5 mm.
• the fibers slide under the edges of the film segments to contact the edge of the masks 13 but only cover the edge of the central portion of the film segments 14 on the width usual 2 mm, while the ribbon sections are completely covered by the fibers.
• the windows 15 made are delimited on the side of the masks 13 by openings 16, 116 in the shape of a star and on the side opposite to the masks 13 by apertures 17, 117 of oval shape and dimensions larger than the openings 16.
• the sectional view illustrated in FIG. 3 shows that on the side of the opening 17 the window 15 will appear oval reflection and star-shaped centered on an oval frame in transparency, while the side of the opening 16, the window will appear star-shaped both in reflection and transparency. If, on the other hand, the film segments 14 are applied offset from the masks 13, on the side of the opening 117, the window will appear in the form of a star offset from the oval frame of the opening 116 as illustrated. in figure 4.
• FIG. 5 illustrates an embodiment of the invention according to which the sheet of fibrous material is produced according to a bijet technique, that is to say that a first jet 29 is produced on a first form 30 and a second jet 31 is made on a second form (not shown) and is conveyed by a conveyor belt 32 above the first jet to be fused with it while the two jets are still in the wet state.
• the shape 30 comprises masks 33 similar to the masks 13 of FIG. 1.
• the jet 29 therefore comprises openings 34 having the masks dimension 33.
• the second jet 31 is formed in exactly the same way as the first jet 29 and therefore includes vertures 35 having dimensions identical to the openings 34.
• Film segments 36 separated from one another and having dimensions greater than the dimensions of the masks 33 are brought by a support strip 37 to be deposited on the first jet 29 immediately upstream of its junction with the second jet 31. During the When the jets join, the film segments 36 are then gripped between the jets and the edge of the film segments 36 is thus trapped over the entire closed contour of the film segments 36.
• the film segments 36 may have a structure similar to the film segments 14 described with respect to the first embodiment of the method according to the invention.
• FIG. 6 illustrates a segment of film whose edge has a serrated contour according to triangular teeth 39 whereas FIG. 7 illustrates a segment of film having a serrated contour according to crenellated teeth 40.
• the width If the teeth are weak, for example less than 2 mm, it is possible to make high teeth similar to the ribbon sections of FIG. 2, which then appear as spokes around the central part of the film segment and provide particularly strong anchoring of the film segment in the fibrous mass.
• the film segments can be transparent, semi-transparent or opaque depending on the desired effect.
• the masks have been mainly illustrated as embossed areas of the porous form, masks reported on the porous form may also be used. It is also possible to deposit on the masks anti-adherent or hydrophobic substances avoiding any deposit of fiber on the masks.
• the ribbon sections have been illustrated completely embedded in the mass of fibrous material, they may be flush with the sheet surface at a sufficient distance from the edge of the film segments so that near the edge of the film segments the ribbon sections are totally trapped in the fibrous material.
• the film segments and sections of ribbon can also be used in a manner known per se to support authentication data produced by metallization, printing, etc.

Landscapes

• Laminated Bodies (AREA)
• Nonwoven Fabrics (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=37401551

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (3)

Family Cites Families (6)

• 2006
  • 2006-03-13 FR FR0602162A patent/FR2898365B1/fr not_active Expired - Fee Related
• 2007
  • 2007-03-12 EP EP07731122.3A patent/EP1994224B1/de not_active Not-in-force
  • 2007-03-12 WO PCT/FR2007/000426 patent/WO2007104855A2/fr not_active Ceased

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events