Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
  • D21J7/00—Manufacture of hollow articles from fibre suspensions or papier-mâché by deposition of fibres in or on a wire-net mould

Definitions

• the present invention concerns a method for the manufacture of objects of stable shape by depositing a fluidized cellulose fibre raw material on a shaping base by controlled suction of a pulp of said fibre raw material onto said base.
• a fluidized fibre raw material means a starting material, which may be in wet form, of a fibrous nature and suited for the manufacture of the desired objects.
• Such starting material may for instance be a fibre pulp material as used for instance for trays and cartons for packaging of fragile and sensitive objects such as fruit, flowers, eggs and objects of for instance glass.
• the pulp material usually consists of a suspended fibrous cellulose.
• the object of the invention is to show how this production method, suitable per se, may be used not only to manufacture relatively small and light objects but also to manufacture large, rather heavy objects with extremely high load capacity characterized by a contour stability substantially based upon a corresponding thickness of the material layer deposited on the moulding base.
• the wall thickness of the said small and light objects is rather small, and the rigidity required in practice is usually obtained by deliberately moulding the wall panels so as to e.g. reinforce the said objects in a manner to make the whole object relatively rigid by supporting each other.
• the stated objective is achieved by that as fibre raw material at least partly a long-fibred starting material is used to increase the drainability of the pulp , and that said pulp is deposited on said base in such a quantity, and that the suction is controlled in such a manner, that by said suction a fibre raw material layer is deposited with a thickness essentially providing the desired shape stability of the object.
• GB Patent Specification No. 1.589.077 concerns means for moulding articles having a complex shape of variable thickness and having high precision of mouldings, this being obtained by varying the concentration of drain holes of the mould over the surface thereof, said holes eliminating the liquid phase from a fibre containing suspension.
• SE Patent Specification No. 324.498 concerns a moulding screen having a differentiated pattern of perforations for obtaining variations of the wall thickness of articles moulded by suction of a fibre containing mass.
• the gist of the invention concerns the use of a pulp which expressly is easily drainable, i.e. that a considerably increased thickness primarily is obtained by increasing the drainability of the material mass which again is obtained by making use of a long-fibred starting material and allows a well controllable and economic process of manufacture.
• the depositing of a fibre raw material layer of the defined thickness means that the negative pressure used for suction may produce a material density in the fibre raw material layer that is highest at the external surface of the material layer facing the mould surface and will have a reinforcing effect, as it is situated at a distance from the through-going centre plane of the object having been deposited.
• the contour stability of this object may according to the invention also be increased in that one or more variations in the layer thickness are produced in and distributed over the fibre raw-material layer by correspondingly varying the suction effect locally in a common suction process for the fibre pulp quantity necessary for the manufacture of the whole object.
• the same working step i.e. the depositing of the fibre raw material on the moulding base, to mould both the final outside desired for the object and, by using the thickness of the material layer, a contour-stability increasing moulded structure in the actual material product constituting the object.
• such a structure may be produced with an embodiment of the method characterized in that the depositing of the fibre raw material with a thickness corresponding to the desired shape stability is carried out so as to produce a coherent structured pattern with a larger layer thickness compared to the other areas.
• a mould may be used having a mould surface, the permeability of which varies in accordance with the local variation or variations respectively of the layer thickness or the coherent structural pattern of the easily drainable fibre pulp layer deposited on the mould surface by suction.
• the method and mould as described may be used in practice for the production of objects from various fibre-containing suspensions, always in the presence of auxiliary materials that may be necessary to create coherence in the material layer produced by suction onto the mould.
• fibre raw material at least partly to use a starting material containing long fibres that is processed to a pulp partly by shake-out in a pulper, partly by preceding, separate, controlled dry grinding by which the starting material is divided into dosable amounts and divided into its fibres, after which the object is manufactured from the pulp produced in this manner.
• a pulper as an essential step in the processing of the fibre raw materials for producing a pulp from which the desired objects are to be manufactured takes place inter alia in cases where the fibre raw materials are received in the form of dry substances in bales, for instance as paper waste.
• Heavy turbulence is produced in the pulper, causing different parts of the material to rub against each other so as to be pulverized and the raw material divided into fibres.
• the pulper is at least partly supplied with a fibre raw material, the fibres of which are already to a substantial degree separated into single fibres, for which reason they are more immediately and simultaneously susceptible to the self-grinding effect and mixing effect obtained in the pulper.
• the grinding degree obtained in the pulper through self-grinding may also be adjusted to be more uniform and the above-mentioned binding of water in the pulp leaving the pulper will thus be more controllable.
• Recycled paper waste exists in many different qualities and gradings. If, prior to the shake-out in the pulper, this material is exposed to a separate, controlled dry grinding, it is often possible to use an inferior and hence cheaper material quality, than if the dividing process were solely carried out as a shake-out in the pulper.
• the present invention also encompasses an embodiment, according to which the preceding separate dry grinding as mentioned above is carried out as a multiple-stage process, making it possible to separate the starting material in dosable amounts in an especially efficient manner.
• the long-fibre starting material having been subjected to a separate, controlled dry grinding is added in measured amounts to the pulp already having been produced in the pulper and subjected to a common time-limited shake-out with said pulp.
• the separate, controlled dry grinding of the fibre raw materials prior to their shake-out in the pulper suggested according to the invention also provides the possibility for the co-application of recycling waste paper in cases where the objects to be manufactured must be shrink-proof and dimensionally stable.
• a starting material with a high content of wood fibre causes less shrinkage than if the fibres were cellulose fibres.
• auxiliary materials such as fillers, chemicals and binding agents.
• the auxiliary materials decide whether the objects manufactured shall be more or less strong, hard or transparent, or weak, soft and capable of absorbing.
• the present invention is also advantageous in connection with the use of such auxiliary materials.
• auxiliary material under the preceding, separate controlled dry grinding will in an especially beneficial manner be able to contribute towards a particularly uniform distribution of the auxiliary materials in the fibre mass being produced. It is, of course, also still possible to add the auxiliary materials to the pulper.
• the shake-out in the pulper is carried out as a manufacturing process dependent on the preceding separate controlled grinding.
• the degree of self-grinding achieved in the pulper can be matched to the degree of the grinding according to the circumstances having been carried out at the preceding dry grinding stage(s).
• dry grounded fibre material may be added, after which the mixture is processed in the pulper for another 5 minutes.
• Objects manufactured from such a mixture pulp may be provided with an especially great thickness, porosity and permeability. That means that the products can have good drainage qualities and can therefore also be manufactured with large wall thicknesses.
• An easily drainable pulp manufactured according to the invention will without problems facilitate a uniform application of the fibre suspension over the mould, even when manufacturing objects with large wall thickness.
• Waste paper also called return paper
• Waste paper may be very inhomogeneous, and may contain fibres with a large variety of fibre lengths.
• the average fibre length is so large that the above mentioned advantages, especially as regards drainage and structure, may be achieved when this paper material is included in the manufacturing process.
• the method according to the invention may also be used for the processing of so-called virgin material.

Applications Claiming Priority (3)

Publications (2)

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• 1988
  • 1988-10-25 DK DK592488A patent/DK168020B1/da not_active IP Right Cessation
• 1989
  • 1989-10-24 CA CA002001296A patent/CA2001296A1/en not_active Abandoned
  • 1989-10-25 AU AU44950/89A patent/AU636585B2/en not_active Ceased
  • 1989-10-25 AT AT0903089A patent/AT398093B/de not_active IP Right Cessation
  • 1989-10-25 BR BR898905455A patent/BR8905455A/pt not_active Application Discontinuation
  • 1989-10-25 DE DE19893991216 patent/DE3991216T/de not_active Withdrawn
  • 1989-10-25 NZ NZ231149A patent/NZ231149A/en unknown
  • 1989-10-25 CH CH2211/90A patent/CH677944A5/de not_active IP Right Cessation
  • 1989-10-25 NL NL8921150A patent/NL8921150A/nl unknown
  • 1989-10-25 WO PCT/DK1989/000250 patent/WO1990004678A1/en active IP Right Grant
  • 1989-10-25 PT PT92098A patent/PT92098A/pt not_active IP Right Cessation
  • 1989-10-25 MX MX018108A patent/MX169792B/es unknown
  • 1989-10-25 ES ES8903596A patent/ES2017055A6/es not_active Expired - Lifetime
  • 1989-10-25 GR GR890100687A patent/GR890100687A/el unknown
  • 1989-10-25 EP EP89912229A patent/EP0441835B1/en not_active Expired - Lifetime
  • 1989-10-25 CN CN89108946A patent/CN1025060C/zh not_active Expired - Fee Related
• 1991
  • 1991-04-24 SE SE9101242A patent/SE467469B/sv not_active IP Right Cessation
  • 1991-04-24 NO NO91911634A patent/NO911634L/no unknown
  • 1991-04-24 GB GB9108931A patent/GB2243575B/en not_active Expired - Fee Related
  • 1991-04-24 GB GB9108932A patent/GB2251402B/en not_active Expired - Fee Related
  • 1991-04-25 FI FI912005A patent/FI98549C/fi not_active IP Right Cessation

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