Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
  • B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
  • B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
  • B05C1/0826—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line the work being a web or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
  • B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
  • B05C1/14—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a travelling band
• • 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
  • D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
  • D21H23/56—Rolls
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C9/00—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important
  • B05C9/04—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying liquid or other fluent material to opposite sides of the work
• • 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
  • D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
  • D21H23/56—Rolls
  • D21H23/58—Details thereof, e.g. surface characteristics, peripheral speed

Definitions

• the invention concerns a method in film transfer coating in a film press, in which press the nip of the film press is formed out of two faces placed against each other and moving in the same direction so that said moving faces are pressed against each other in the nip, and in which press a coating agent or surface size is applied as a film onto at least one of the moving faces that form the film press nip and that are subjected to pressing, in which connection the coating agent or surface size is transferred in the nip between the moving faces onto the paper or board web running through the nip, and after the nip the web is separated either directly from the nip or so that it follows one or the other of the moving faces.
• the invention also concerns a film press intended for carrying out the method, which press comprises a film press nip formed out of two faces that are placed against each other and that move in the same direction so that said moving faces are pressed against each other, through which nip the paper or board web has been passed, and which film press is provided with coating means for application of a coating agent or surface size as a film onto at least one of the moving faces that form the film press nip and that are subjected to pressing, from which face the coating agent or surface size has been arranged to be transferred in the film press nip onto the paper or board web, in which connection, after the nip, the web has been fitted to be separated either directly from the nip or so that it follows one or the other of the moving faces.
• the application of a size or of a paste onto a paper is carried out so that, depending on whether the paper is to be coated from one side only or from both sides, coating agent films of the desired thickness are applied, by means of applicator devices, onto the face/faces of one roll or both rolls in the film size press, in which connection these coating agent films are transferred onto the paper web in a nip formed by the size press rolls as the paper web runs through said nip.
• the film rolls in film size presses are provided with resilient coatings, and the application onto the roll face can be carried out by using some known blade coater, a bar coater provided with a smooth or grooved coating bar, or an equivalent nozzle equipment.
• mist arises from splitting of the coating agent film in the film press when the web is separated from the film roll.
• the coating agent film splits so that most of the film remains on the paper, whereas a smaller portion remains on the face of the film roll.
• the point of separation of the web from the roll does not remain the same, but the point of separation "wanders" along the roll face. In this connection, fluttering may have occurred in the web, which may again have resulted in web breaks and in their well-known detrimental consequences. Further, wandering of the web separation point in the machine direction and also in the cross direction causes a serious problem of mist formation.
• the object of the present invention is to provide a novel, improved solution for the control of the line of separation of the web as well as for the problems related to the formation of mist of coating agent or surface size and to spreading of the mist.
• the method in accordance with the invention is mainly characterized in that the web is separated from the nip so that, at least at one side of the web, the curve radius of the opening geometry is larger than 0.75 metre.
• the film press in accordance with the invention is mainly charac- terized in that the curve radius of the opening geometry after the film press nip is, at least at one side of the web, larger than 0.75 metre.
• Figure 1 is a fully schematic side view of a film press intended for two-sided coating or surface sizing of a web in which the method in accordance with the present invention is applied.
• Figure 2 is an illustration corresponding to Fig. 1 of a film press intended for onesided coating or surface sizing of a web in which the method in accordance with the present invention is applied.
• Figure 3 is an illustration corresponding to Figs. 1 and 2 of a belt embodiment of a film press in accordance with the present invention intended for one-sided coating or surface sizing of a web.
• the film press is denoted generally with the reference numeral 10.
• the film press 10 comprises a film press nip N, which is formed between a first and a second film press roll 1,2.
• the paper or board web W is passed into said nip N, in Fig. 1, as guided by a guide roll 5.
• the film press 10 in Fig. 1 coats or surface- sizes the web W from both sides, and, thus, each film press roll 1,2 is provided with applicator means 3,4, by whose means the coating agent or surface size is applied as a film F j ,F 2 onto the face l',2' of each roll.
• the films F ⁇ ,V 2 are transferred in the film press nip N onto the web W, and the coated or surface-sized web W' is passed out of the nip N, in Fig. 1, so that it follows the face 2' of the second film press roll 2.
• the radii of the film press rolls 1,2 are denoted with the references R 1 and R 2 .
• Fig. 2 illustrates a film press, which is denoted generally with the reference denotation 10A.
• the film press 10A comprises a film press nip N, which is formed between a first and a second film press roll 1A,2A.
• the paper or board web W is passed into said nip N as guided by the guide roll 5.
• the film press 10A shown in Fig. 2 differs from the solution shown in Fig. 1 in the respect that the film press 10A of Fig. 2 coats or surface-sizes the web W from one side, and, thus, just one of the rolls in the pair of rolls in the film press 10A, in Fig.
• the first film press roll 1A is provided with applicator means 3A for application of a coating agent or surface size as a film F 1 onto the face 1A' of the roll concerned.
• the second roll 2A in the film press 10A operates just as a backup roll, by whose means the desired linear load is produced in the nip N.
• the film F j is transferred onto the web W, and the web W', which has been coated or surface-sized from one side, is passed out of the nip N, in Fig. 2, so that it follows the face 2A' of the second film press roll 2A.
• the radii of the film press rolls 1A,2A are denoted with the reference denotations Ri and R 2 .
• Fig. 3 shows a film press, which is denoted with the reference denotation 10B.
• the film press 10B comprises a film press N, which is, unlike Figs. 1 and 2, formed between a first and a second film press roll 1B,2B so that, in the solution shown in this figure, a belt IB' has been passed around the first film press roll IB, which belt runs through the nip N and which has been formed as an endless belt loop by means of turning rolls 6,7,8.
• the paper or board web W is passed into said nip N, in Fig. 3, as guided by the guide roll 5.
• the film press 10B belt IB' is provided with an applicator device 3B, by whose means the coating agent or surface size is applied as a film F j onto the belt IB'.
• the second roll 2B in the film press 10B operates exclusively as a backup roll, by whose means the desired linear load can be produced in the nip N.
• the film F j is transferred in the film press N from the belt IB' onto the web W, and the web W', which has been coated or surface-sized from one side, is passed out of the nip N, in Fig. 3, so that it follows the belt IB', from which it is separated after the nip N.
• Figs. 1 to 3 are just exemplifying illustrations of how the coating and/or surface sizing can be carried out in a film press and how the geometry of a film press can be controlled, the invention being, however, not confined to these exemplifying embodiments alone.
• R 1 and R 2 radii of the rolls.
• a pair of rolls is employed which exceeds the value 1.33 of the prior-art size presses with the largest rolls 1.5 m + 1.5 m, computed from the formula 1/R 1 + 1/R 2 . It is advantageous to increase the diameter of the hard-faced backup roll, because this roll is replaced very rarely. This can be achieved by using a backup roll whose diameter is larger than 1.5 metres. It is, however, possible that at least one of the rolls that form the nip has a diameter larger than 1.5.
• the taking out of the web in the direction of the tangent of the film roll, either directly out of the nip or so that the web follows the film roll.
• the taking out of the web would take place in compliance with the requirements of size of said roll diameters or so that the belts are separated from the film on one of the belts at an invariable angle.
• the coating should be preferably dried on the belt in order to increase the filter layer formed on the coating, which is known to reduce the formation of mist.
• the nip N in the film press is formed out of two faces (roll face / belt) placed one against the other and moving in the same direction, which faces are loaded by pressing them against each other in the nip.
• the coating agent or surface size is applied as a film F l5 F 2 onto at least one of the moving faces that form the film press nip N and that are subjected to pressure, in which connection the coating agent or surface size is transferred in the nip N between the moving faces onto the paper or board web W running through the nip.
• the web is separated either directly from the nip or so that it follows one of the moving faces.
• the web is separated from the nip so that the curve radius of the opening geometry is larger than 0.75 m at least at one side of the web.
• the diameter of at least one of the rolls is larger than 1.5 metres.
• At least one (cf. Fig. 3) or both of the moving faces subjected to pressure and forming the nip can be formed out of a belt that runs through the nip and that has been formed as an endless loop.
• one or both of the moving faces that form the nip and that are subjected to pressure can consist of a roll face.
• the moving face subjected to pressure and placed at the web side opposite in relation to the web face to be coated or surface-sized can be hard, in particular a metal face, or, on the other hand, it can consist of a soft coating, in particular of a polymer coating.
• the moving face subjected to pressure and placed at the web side opposite in relation to the web face to be coated or surface-sized can be doctored with water or moistened with water mist or steam in order to facilitate the separation of the web.
• said face can be provided with a coating that repels the coating agent of surface size.
• the coating can be dried in order to increase the filter layer formed by the coating.

Landscapes

• Application Of Or Painting With Fluid Materials (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Press Drives And Press Lines (AREA)
• Dental Preparations (AREA)
• Materials For Medical Uses (AREA)
• Decoration By Transfer Pictures (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=8552055

Family Applications (1)

Country Status (6)

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Family Cites Families (3)

• 1998
  • 1998-06-23 FI FI981446A patent/FI104435B/fi not_active IP Right Cessation
• 1999
  • 1999-06-22 EP EP99931320A patent/EP1092063B1/fr not_active Expired - Lifetime
  • 1999-06-22 DE DE69910034T patent/DE69910034T2/de not_active Expired - Lifetime
  • 1999-06-22 WO PCT/FI1999/000548 patent/WO1999067468A1/fr active IP Right Grant
  • 1999-06-22 AU AU47871/99A patent/AU4787199A/en not_active Abandoned
  • 1999-06-22 AT AT99931320T patent/ATE246286T1/de active

Non-Patent Citations (1)

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