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 manu ⁇ facture of contour-stable objects by the depositing of a fluidized fibre raw material on a moulding foundation by suction of a pulp of the fibre raw material on this foun- dation.
• a fluidized fibre raw material means a starting mate ⁇ rial, 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 indicate how this in itself suitable production technique 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 which is substantially based on a corresponding thickness of the material layer deposited on the moulding foundation.
• the wall thickness of the said small and light objects is rather thin and the rigidity necessary in practice is usually obtained by deliberately moulding the wall panels which for instance support the said objects as the walls produce a rather rigid total object by mutually supporting each other.
• the stated objective is a- chieved by applying to the foundation a pulp formed by the fluidized fibre raw material and easily to be drained in such quantity and by controlling the suction in such a way that on the foundation is deposited a fibre raw material layer of such thickness as to provide in all essentials the contour stability desired for the object by suction.
• the contour stability of this object may according to the invention also be increased by procuring in the fiber raw material layer and distributed over this one or more va- riations in the layer thickness by correspondingly locally varying the suction effect during a joint suction process for the fibre pulp volume necessary for the manufacture of the whole object.
• the contour stability of this object may according to the invention also be increased by procuring in the fiber raw material layer and distributed over this one or more va- riations in the layer thickness by correspondingly locally varying the suction effect during a joint suction process for the fibre pulp volume necessary for the manufacture of the whole object.
• a contour stability in ⁇ creasing moulded structure in the actual material object forming the object According to the invention such a struc- ture will for instance be able to be shaped as a connected -structural pattern with a thicker layer thickness compared with the other parts of the object.
• a suitable way for the car ⁇ rying through of the method is characteristic in that,- for suction of a pulp of the fibre raw material, which is easily to be drained, in the desired thickness, a mould is used which at negative pressure is permeable by a gaseous active working medium and which has a by the working medium per- meable mould surface the permeability of which is adjusted to the thickness of the fibre raw material layer to be de ⁇ posited by suction of the pulp on this surface.
• a mould having a mould surface with a permeability varying in accordance with the layer thickness of the local variation or variations respectively or the coherent structural pat ⁇ tern of the easily drainable fibre pulp layer deposited on the mould surface by suction may be used according to the invention.
• an embodiment of this me- thod may be characterized by the use for suction of an easi ⁇ ly drainable pulp of the fibre raw material in the desired thickness of a mould which at negative pressure is permeable by a gaseous active working medium which at least as regards the outline-forming part consists of a partial composite ma- terial the particles of which are fixed together for the formation of a contour-stable mould surface at the same time as they together limit passages open to the working medium, which passages extend through the composite material to the outside surface of the mould, and that the thickness of at least the composite material layer forming the mould surface is adjusted according to the thickness of the fibre raw ma ⁇ terial layer to be deposited by suction of the pulp to this surface.
• Such a mould may be manufactured on the basis of a cheap, inorganic raw material such as sand as well as by means of a production technique which is simple, of short duration and thus also cheap.
• the total production costs of the mould may be kept at a low level and this embodiment will consequently be suitable for the production of a small number of products.
• a mould may, according to the invention, be used in which the com ⁇ posite material formed by the mould surface has a thickness that varies in accordance with the layer thickness of the local variation or variations, respectively, or the desired coherent structural pattern of the easily drainable fibre pulp layer deposited on the mould surface by suction.
• a mould may be used the per ⁇ meable mould surface of which is composed of particles with varying particle size, the particle size being small in the part forming the mould surface of the mould and larger in an underlying supporting layer for this part.
• the mould strength necessary for the carrying through of a production process may be achieved in a simple way by mixing the mould particles with suitable binding agents which may contain adhesion-improving agents and by hardening the mould manufactured by such mixture by for instance heat treatment,. Also wedging between the particles may be used to give the mould strength.
• a mould having at the bottom a basic part in which the composite particles are linked together by a real fusion compound whereas the particles in the rest of the mould are linked together by a hardening conglutinating compound.
• Such a mould is characterized by good strength which will also enable it to resist considerable working pressure. It is also within the scope of the invention to use a mould the mould surface of which is shaped with such strength that the mould may be used for the finishing pres ⁇ sing of a moulded object.
• Finishing pressing may not only be used for quick removal of water from the pulp layer de ⁇ posited on the mould surface, but also to achieve an espe ⁇ cially good material density in the deposited, rather thick fibre material layer and thus an especially high degree of contour stability in the final object.
• the desired porosity of the mould may be achieved by an appropriate choice of the grain size and the distribution of the particles of which the permeable mould surface may be composed both to obtain favourable conditions for the fixing compound between the particles and for a suitable di- mensioning of the porosity in order to avoid an undesired pressure drop across a building material which is unneces ⁇ sarily dense.
• the above procedure and mould may as mentioned in prac ⁇ tice be used for the production of objects of various fibre- containing suspensions, everything in the presence of the auxiliary materials which may be necessary to create connec ⁇ tion in the material layer obtained by suction onto the mould.
• the removal of an object formed by the depositing of a fluidized fibre raw material on the outline-forming out ⁇ side of the mould surface by means of a gaseous working me ⁇ dium may in practice be performed place by the object being affected by compressed air through the air passages of the mould and thus lifted free of the mould.
• the ob- ject will, however, usually still be rather soft and it may therefore for the purpose of removing the object from the casting mould be appropriate to use a transfer mould which is adapted to interact with the side of the object pointing away from the mentioned outline-forming outside for the. re- moval of the object from this outside and for the subsequent placing of the object on for instance a conveyer belt taking the object to a drying chamber.
• the transfer mould is producible directly on the basis of an object produced on the casting mould as on this object a first auxiliary mould (negative) of for instance gypsum is produced corresponding to the side of the object pointing away from the casting mould and on this first auxiliary mould (negative) a second auxiliary mould (positive) is pro ⁇ **d for instance also from gypsum and the transfer mould (negative) is then formed directly on this second auxiliary mould.
• the permeable mould surface may be kept clean by, prior to the start of the depositing process or the transfer pro ⁇ cess, exposing for cleaning purposes the mould surface to an air current passing through the mould passages for a ga ⁇ seous medium.
• a mould used in accordance with the invention and con ⁇ structed by a particle composite material may be manufac ⁇ tured in such a way that it may after use or in case of wear be regenerated as the particle-shaped building material of the mould may be recycled.
• a pulp which is to be easily drained it is possible, according to the invention, as fibre raw material at least partly to use a starting material con ⁇ taining long fibres which is processed to a pulp partly by means of a shake-out in a pulper, partly by a preceding, se- parate, controlled dry grinding by which the starting mate ⁇ rial is divided into dosage amounts and divided into its fibres whereupon the object is manufactured from the pulp thus created.
• a pulper as an essential step in the pr ces- sing of the fibre raw materials for the creation of a pulp from which the desired objects are to be manufactured takes place among other things in cases where the fibre raw mate ⁇ rials are received in the form of dry substances in bales, for instance as paper waste.
• the method according to the invention achieves that to the pulper is at least partly added a fibre raw material the fibres of which are already to a substantial degree sepa ⁇ rated into single fibres why they are more instant and at the same time susceptible to the self-grinding effect and mixing effect obtained in the pulper.
• the pulper proces- ses a more uniform raw material also the grinding degree ob ⁇ tained in the pulper through self-grinding may be adjusted to be more uniform and the above-mentioned binding of water in the pulp leaving the pulper will thus be more control ⁇ lable.
• the same procedure will, however, also result in other advantages which are especially valuable in case of recyc ⁇ ling of paper waste.
• Recycled paper waste exists in many different qualities and grading ⁇ . If this material prior to the shake-out in the pulper is exposed to a separate, controlled dry grinding, it is often possible to use a poorer and thus cheaper mate ⁇ rial quality, than if the division process was only carried out as a shake-out in the pulper.
• the preceding separate dry grinding as mentioned above as a multiple-stage process whereby it is possible to separate the starting material in dosage amounts in a special effi ⁇ cient manner.
• waste paper material containing plastic, water resistant paper, plastic laminated cartons and paper to the degree desired can be separated into fibres and other particles. Separated constituents not being paper can be screened off before entering the pulper, or it is possible to let these constituents since they exist in pulverized form enter into the following production pro ⁇ cess.
• a long fibre starting material having been subjected to a separate controlled dry grinding be added to an already in the pulper formed pulp and be subjected to a joint time-limited shake-out with this.
• the separate, controlled dry grinding suggested accord ⁇ ing to the invention of the fibre raw materials prior to their shake-out in the pulper 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 measure proof.
• a starting material with a high content of wooden fibre causes less shrinkage that if the fibre were cellulose fibre. It has turned out that by applying the me ⁇ thod according to the invention it is even possible to add to a wooden paper raw material a substantial amount of cheap recycling paper including carton waste which not necessarily is wooden since it is possible to manufacture due to the preceding separate controlled dry grinding of the raw mate ⁇ rial a pulp which causes no undesired shrinkage of the ob ⁇ jects manufactured.
• auxiliary materials such as filling material and chemicals and binding agents.
• the auxiliary materials decide whether the objects manufactured shall be more or less strong, hard or transpa ⁇ rent, or weak, soft and absorbing.
• the present invention is also advantageous in connection with the application of such auxiliary materials.
• auxiliary materials at different stages of the total manu ⁇ facturing process.
• the achieved open structure of the final pulp obtained as a result of this particular invention, •even facilitates a better access for auxiliary materials so that e.g. a binding material may be applied more or less in ⁇ tegrating on the surface of the objects in order to increase the strenght of the wall.
• auxiliary material under the preceding separate, controlled dry grinding will in a especially good manner be able to further a particular uniform distribution of the auxiliary materials in the ma- nufactured fibre mass. 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 manu- facturing process dependent on the preceding separate, con ⁇ trolled grinding.
• the obtained degree of self-grinding in the pulper can be adjusted in accordance with the degree of the grinding which according to the cir ⁇ cumstances has been carried out at the preceding dry grin- ding stage(s).
• a paper pulp which in the pul ⁇ per is separated into a normal, at self grinding obtained grinding degree of 60o SR (Schopper-Riegler) , be added dry grounded fibre material whereafter the mixture is processed in the pulper for 5 minutes more.
• Objects manufactured from such a mixture pulp may be provided with a special heavy thickness, porosity and permeability. That means that the products can have good drainage qualities and therefore also can be manufactured with large wall thickness.
• An easily drainable pulp manufactured according to the invention facilitates unproblematically a uniform addition of the fibre suspension over the mould even in cases of manufacturing objects with large wall thickness.
• Waste paper also called return paper
• Waste paper may be very com ⁇ posite, and contain fibre with a large variety of fibre lengths.
• the method according to the invention will also be a- vailable for the processing of so-called virgin material.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Paper (AREA)
• Pallets (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8146198

Family Applications (1)

Country Status (20)

Cited By (4)

Families Citing this family (3)

Citations (2)

Family Cites Families (14)

• 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

Patent Citations (2)

Also Published As

Similar Documents

Legal Events