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
  • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
  • D21F11/02—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the Fourdrinier type
  • D21F11/04—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines of the Fourdrinier type paper or board consisting on 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/24—Addition to the formed paper during paper manufacture
• • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/50—Spraying or projecting

Definitions

• the present invention relates to a process for the manufacture of a multilayer pulp product, in particular a product selected from paper and cardboard and which has the essential characteristic of incorporating a load between layers.
• the outer layers are distinguished which give said paper or cardboard its final appearance and the inner layers, which may consist of virgin pulp, recycled pulp or mixtures of both.
• the inner layers have a dark color that sometimes it is necessary to mask with the outer layers, for which it is customary to add one or several layers of white fibers
• the loads are of vital importance since through them a saving in the amount of virgin or recycled fiber used is achieved.
• the purpose of adding loads during manufacturing is also the improvement or acquisition of certain desired properties in the final product: improvement of optical properties such as whiteness, opacity, brightness and color; improvement of properties related to fluid permeability, such as water or ink penetration, oil penetration and porosity or resistance to passage from air.
• the addition of loads to the paper also allows to increase the speed of the maguine as it increases its production.
• International application WO-9600816 describes a method and a device for applying a film of a coating material on a web or fabric of fibers in a paper or cardboard box.
• the coating material is applied on the surface of the pulp product framework by means of a low pressure and high flow spray system.
• the system is equipped with a series of spray guns adjacent to the web of the pulp product.
• this procedure is intended only for the manufacture of monolayer paper.
• the monolayer paper coating described in this way has the disadvantage that it is difficult to achieve a correct distribution of the load throughout the entire section of the paper, since depending on the application point the penetration of the load within the fiber network will vary. radically
• European patent application EP-0 373 276-A1 describes a method and device for the continuous spraying of adjuvants on a permeable web of fibers arranged on a belt that travels.
• the system allows the adjuvants to be sprayed in different moisture stages of the sheet in formation by means of one or several spray ramps.
• Each of them is supported by a movable support frame arranged transversely in relation to the direction of movement of the belt.
• Each ramp is constituted by two conduits provided with boguillas for the transport of the adjuvants, being starch the product that is pulverized and penetrates along the entire thickness of the sheet.
• the present invention relates to a process for the manufacture of a multilayer pulp product. Said process consists essentially of applying a load between at least two layers of moving fiber material before the definitive bonding between them. DETAILED DESCRIPTION OF THE INVENTION
• the present invention relates to a process for the manufacture of a multilayer pulp product, characterized in that it comprises:
• the position of the means, or means, of application with respect to the layering section of fiber material can be variable. Loads can be dosed by means of application on one or another layer.
• the load is introduced at a distance between 1 and 70 cm on the mobile fiber network and preferably between 5 and 40 cm.
• the loads used in the process of the present invention are applied by one or several means which are located transversely on the mobile fiber network and said means of application are arranged in one or several series at different distances from the entrance box of the maguina. of pulp product manufacturing.
• the loading application means may also be arranged at an angle of inclination with respect to the mobile network of fibers between 0 and 90 degrees, this angle preferably being 25 degrees.
• the final configuration of the application system depends essentially on the speed and configuration of the pulp product manufacturing maguine.
• the means for applying the load are located transversely to the direction of travel of the moving belt.
• the loading application can be carried out through various means of application, being able to be introduced in a single application or in successive loading layers.
• the loading application means are preferably boguillas, the load being applied by spraying a suspension thereof between layers of pulp material (the mobile fiber network moves at a speed which is between 50 and 2000 meters per minute).
• boguillas allows the introduction of a load according to a form selected between conical jets and flat jets with variable opening angles, preferably 602. Spraying can be carried out by means of a system which comprises boguillas and a return, which controls effectively the flow or flow in the boguillas.
• the flow in the boguillas is regulated by means of a control and said return.
• the control means is preferably selected from a pressure regulator, a flow regulator and an eguipated pump with a frequency variator.
• the charge is introduced with a transfer efficiency greater than 70%, preferably between 90% and 100%.
• the load can penetrate into the web of moving fibers with a depth that comes determined by the distance of the means of application of the load with respect to the input box.
• the load is sprayed at the end of the sheet formation at a distance from the inlet box which guarantees little penetration (to achieve the best coverage of the inner layers).
• the product manufacturing maguina is preferably a paper or cardboard maguine, and the multilayer pulp product is paper or cardboard.
• the process of the present invention can be carried out in any type of paper or cardboard maguine, whereby said maguine can be a Fourdrinier type maguine, a round-shaped maguine or a maguine combination of both.
• the filler is preferably of inorganic origin, although it may comprise organic components.
• the inorganic fillers in the process of the present invention calcium sulfate, calcium carbonate, titanium dioxide, talc, kaolin, alumina trihydrate, or a mixture of two or more of these components is preferably used.
• the carbonate may be selected from a natural calcium carbonate and a precipitated calcium carbonate.
• the filler used is high whiteness calcium sulfate and even more preferably an anhydrous high white calcium sulfate.
• Calcium sulfate is selected from - natural anhydrous calcium sulfate, anhydrous calcium sulfate from guideline synthesis and
• anhydrous calcium sulfate obtained by dehydration of a calcium sulfate selected from - calcium sulfate natural hemihydrate, - calcium sulfate natural dihydrate, - calcium sulfate dihydrate from guimetic synthesis and.
• calcium sulfate hemihydrate from guimetic synthesis.
• calcium sulfate is dispersed in water (by strong stirring) in proportions that comprise up to 60% by weight relative to the total mass of the suspension.
• Load granulometry is also an important factor for the process of the invention.
• the fine granulometry, the hiding power and the high refractive index of calcium sulfate improve the opacifying capacity of the white layer.
• the calcium sulfate used in the invention has an average particle size between 0.5 and 50 ⁇ m.
• the filler has a particle size between 0.5 and 10 ⁇ m.
• the filler may comprise a dispersant in a proportion comprised between 0.01% and 1% by weight of the dried filler.
• the load is applied as an aqueous suspension, the amounts of water and load being preferably controlled by weighing. Furthermore, said load is generally applied by controlling the flow by means of a flow regulator and / or by a pressure controller.
• the rheological properties of calcium sulfate make it possible to work with a wide range of dry extracts, so that the optimal amount of loading between layers can be determined for each type of quality to be manufactured.
• the charge is applied as an aqueous suspension which comprises between 99% and 40% water. It preferably comprises between 90% and 70% water.
• the amount of cargo deposited on the fiber network comprises between 0.5 g / m 2 and 50 g / m 2 , and most preferably between 5 g / m 2 and 15 g / m 2 .
• the filler may optionally comprise one or more additives. For example, it may comprise different types of starches or mixtures thereof.
• the fibrous material constituting the multilayer pulp product produced by the process of the present invention may consist of pulp selected from virgin pulp, recycled pulp, destined or not, all types of pulp bleached or not, and mixtures of the above.
• the present invention has as a further object a paper or cardboard product produced according to the described process.
• a load saving is achieved due to the fact that load retention exceeds 70% is achieved without the use of external guide agents.
• Another additional advantage of the process of the present invention is that it allows the inner and outer layers of the final product to be of inferior quality, significantly reducing the cost of the final product. If the same quality of the inner and outer layers is maintained, the application of loading between layers allows to obtain a final product of better overall quality.
• Another additional advantage of the process of the present invention is that the white one or more can be replaced (if the final product consists of several external white layers) while maintaining the desired optical properties.
• Another additional advantage of the process of the present invention is that it also allows to reduce the weight of the white layer maintaining the desired optical properties of the final product, significantly reducing the cost of the manufactured product.
• Another additional advantage of the process of the present invention is that the use of calcium sulfate improves the efficiency and homogeneity of the coating between layers.
• Figure 1 shows a series of locations of a device designed for the introduction of loads according to the method of the invention and suitable for different maguine configurations.
• Figure 1 shows a series of locations of a device designed for the introduction of loads according to the method of the invention and suitable for different maguine configurations.
• - 1 represents a load application means
• - (a) shows a section of a combination of Fourdrinier eagles and round shapes
• Figure 2 shows a system of introduction of spray loading, said system comprising a series of boguillas which allow to pulverize the suspension of load in jets in conical or flat form.
• a jet scheme is shown in flat form 2, or in conical form 3.
• Figure 3 shows a possible configuration of the load application means with respect to the mobile fiber network.
• - "h" represents the distance between the application medium and the fiber mesh surface - 4 represents the pulverized charge
• FIG. 4 shows a scheme of the preparation, storage and spraying of cargo in the form of a suspension.
• a cargo storage section 7 a dilution section of the preparation 8
• a storage section of the cargo suspension 9 a sprinkler system 10 which comprises a final batch 10a is observed
• a section of the load introduction device between the layers of pulp product 10b is observed
• Figure 5 shows the section or sprinkler system 10 of Figure 4. It is a type scheme of the introduction of load in the form of a suspension, in which the flow control points are observed.
• a load filter 11 the flow control point 12, the positions of the flow meters 12a and 12b, and the section of the load spray ramp 13, between the pulp product layers are observed .
• This system may be subject to specific modifications that allow both the deletion or addition of elements and the modification by other more sophisticated components.
• a network of cellulose fibers from white recycled paper is arranged on the conveyor belt of a Fourdrinier paper maguine that moves at 142 m / s.
• a network of cellulose fibers from white recycled paper is arranged at a distance of 40 cm (h in Figure 3) on the surface of the fiber network It has a load spray system provided with 14 boguillas as shown in Figure 2.
• the angle of inclination ⁇ - as shown in Figure 3 - of the boguillas with respect to the mobile fiber network is 259.
• a 25% aqueous suspension of anhydrous calcium sulfate (from dehydration of calcium sulfate dihydrate) with an average particle size of 3 ⁇ m is prepared.
• Water and load quantities are controlled by weighing.
• 17 g / m 2 of anhydrous calcium sulfate are dosed on the surface of the moving paper (10% by weight on the white layer production).
• the load flow is controlled by an automatic flow regulator, the spray point being located at the end of the formation table and after the water line. At the end of the training table the union of the white layer with the gray support takes place.
• the weight of the white layer was reduced from 81 to 65 g / m 2 with the consequent economic savings.
• the weight value of the white layer (81 g / m 2 ) and maintaining the same mechanical properties Since they were obtained with kaolin, it was possible to increase the percentage of ashes from 18% to 23% by spraying calcium sulfate.

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Citations (6)

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• 2001
  • 2001-06-06 WO PCT/ES2001/000234 patent/WO2002099191A1/es active Application Filing
  • 2001-06-06 EP EP01938274A patent/EP1426489A1/en not_active Withdrawn
  • 2001-06-06 BR BR0117070-8A patent/BR0117070A/pt not_active Application Discontinuation
  • 2001-06-06 CA CA002449878A patent/CA2449878A1/en not_active Abandoned
• 2003
  • 2003-12-04 US US10/728,077 patent/US20040244927A1/en not_active Abandoned

Patent Citations (6)

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