FI20195008A1 - Method of treating a fiber web and a treatment system for treatment of a fiber web - Google Patents

Method of treating a fiber web and a treatment system for treatment of a fiber web Download PDF

Info

Publication number
FI20195008A1
FI20195008A1 FI20195008A FI20195008A FI20195008A1 FI 20195008 A1 FI20195008 A1 FI 20195008A1 FI 20195008 A FI20195008 A FI 20195008A FI 20195008 A FI20195008 A FI 20195008A FI 20195008 A1 FI20195008 A1 FI 20195008A1
Authority
FI
Finland
Prior art keywords
sizing
fiber web
heat
treatment
nip
Prior art date
Application number
FI20195008A
Other languages
Finnish (fi)
Swedish (sv)
Inventor
Mika Viljanmaa
Henri Vaittinen
Tuulia Mäkelä
Jari Ilomäki
Jani Hakola
Reijo Pietikäinen
Vesa Hyppönen
Kari Juppi
Seppo Luomi
Tapio Pitkäniemi
Original Assignee
Valmet Technologies Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valmet Technologies Oy filed Critical Valmet Technologies Oy
Priority to EP19184856.3A priority Critical patent/EP3617403B1/en
Priority to EP21170343.4A priority patent/EP3875684B1/en
Priority to CN201910812882.4A priority patent/CN110872792A/en
Publication of FI20195008A1 publication Critical patent/FI20195008A1/en

Links

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
    • 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
    • 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
    • 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
    • B05C1/0813—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 characterised by means for supplying liquid or other fluent material to the roller
    • 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
    • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
    • B05C5/005—Curtain coaters
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/28—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B05D3/0254—After-treatment
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G1/00—Calenders; Smoothing apparatus
    • D21G1/0066—Calenders; Smoothing apparatus using a special calendering belt
    • 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
    • D21H21/16—Sizing or water-repelling agents
    • 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
    • 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
    • D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
    • 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
    • D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
    • D21H23/42—Paper being at least partly surrounded by the material on both sides
    • 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
    • D21H23/46—Pouring or allowing the fluid to flow in a continuous stream on to the surface, the entire stream being carried away by the paper
    • D21H23/48—Curtain coaters
    • 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
    • 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
    • D21H23/62—Reverse roll coating, i.e. applicator roll surface moving in direction opposite to that of the paper
    • 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
    • D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
    • D21H25/04—Physical treatment, e.g. heating, irradiating
    • D21H25/06—Physical treatment, e.g. heating, irradiating of impregnated or coated paper

Landscapes

  • Paper (AREA)

Abstract

The invention relates to a method of treating a fiber web, in which method the fiber web is sized in a sizer (10), in which the sizing agent (T) is applied onto the fiber web by two sizing rolls (11,12) in a sizing nip (N). The fiber web (W) is sized with sizing agent (T) comprising fiber suspen-sion by indirect curtain sizing in a curtain sizer (10) and in the sizing nip (N) at substantially uniform pressure distri-bution and uniform speed in cross-direction of the fiber web (W). After the sizing the fiber web (W) is heat-treated in a heat-treatment zone (Z) of a heat-treatment device (20). The invention also relates to a treatment system for treatment of a fiber web, which system comprises a sizer (10) comprising sizing rolls (11,12) forming a sizing nip (N). The system further comprises a heat-treatment device (20) comprising a heat-treatment zone (Z). The sizer is a curtain sizer (10) with indirect application of sizing agent (T) comprising fiber suspension and one of which sizing rolls is a deflection compensated roll and a substantially straight sizing nip is formed.

Description

Method of treating a fiber web and a treatment system for treatment of a fiber web
In general, present invention relates to treating of fiber webs in a fiber web production line. More especially the present invention relates to a method according to 5 preamble part of the independent method claim and to a treatment system according to preamble part of the independent treatment system claim.
In this description and the following claims by fiber webs are meant for example a paper and board webs.
Fiber webs, such as paper and board webs are available in a wide variety of types 10 and can be divided according to basis weight in two grades: papers with a single ply and a basis weight of 25-300 g/m2 and boards manufactured in multi-ply technology and having a basis weight of 150-600 m/m2. It should be noted that the borderline between paper and board is flexible since board grades with lightest basis weights are lighter than the heaviest paper grades. Generally speaking, pa15 per is used for printing and board for packaging.
The subsequent descriptions are examples of values presently applied for fiber webs, and there may be considerable fluctuations from the disclosed values. The descriptions are mainly based on the source publication Papermaking Science and Technology, section Papermaking Part 3, edited by Rautiainen, P., and published 20 by Paper Engineers’ Association, Helsinki 2009, 404 pages.
Mechanical-pulp based, i.e. wood-containing printing papers include newsprint, uncoated magazine and coated magazine paper.
Today's newsprint furnishes mostly contain between 80 and 100 % deinked pulp (DIP). The rest of the furnish is mechanical pulp (typically TMP). However, there is 25 also newsprint made of 100 % mechanical fiber furnishes. DIP based newsprint may contain up to 20 % filler. The filler content of a virgin-fiber based newsprint furnish is about 8 %.
General values for CSWO newsprint can be regarded as follows: basis weight 4048.8 g/m2, PPS s10 roughness (SCAN-P 76-95) 4.0-4.5 pm, Bendtsen roughness 30 (SCAN-P21:67) 150 ml/min, density 600-750 kg/m3, brightness (ISO 2470:1999)
58-59 %, and opacity (ISO 2470:1998) 92-95%.
20195008 PRH 09 -01- 2019
Uncoated magazine paper (SC-supercalendered) grades usually contain 50 % 75 % mechanical pulp, 5 % - 25 % chemical pulp, and 10 % - 35 % filler. The paper may also contain DIP. Typical values for calendered SC paper (containing e.g. SC-C, SC-B, and SC-A/A+) include basis weight 40-60 g/m2, ash content (SCAN-P 5 5:63) 0-35%, Hunter gloss (ISO/DIS 8254/1) <20-50%, PPS s10 roughness (SCAN-P 76:95) 1.0-2.5 pm, density 700-1250 kg/m3, brightness (ISO 2470:1999) 62-75%, and opacity (ISO 2470:1998) 90-95%.
Coated mechanical papers include for example MFC (machine finished coated), LWC (lightweight coated), MWC (medium weight coated), and HWC (heavy weight 10 coated) grades. Coated mechanical papers usually contain 45 % -75 % mechanical or recycled fiber and 25 % - 55 % chemical pulp. Semi chemical pulps are typical in LWC paper grades made in the Far East. The filler content is about 5 % -10 %. The grammage is typically in the range 40-80 g/m2.
General values for LWC paper can be regarded as follows: basis weight 40-70 15 g/m2, Hunter gloss 50-65%, PPS S10 roughness 1.0-1.5 pm (offset) and 0.6-1.0 pm (roto), density 1100-1250 kg/m3, brightness 70-75%, and opacity 89-94%.
General values for MFC paper (machine finished coated) can be regarded as follows: basis weight 48-70 g/m2, Hunter gloss 25-40%, PPS S10 roughness 2.2-2.8 pm, density 900-950 kg/ m3, brightness 70-75%, and opacity 91-95%.
General values for MWC paper (medium weight coated) can be regarded as follows: basis weight 70-90 g/ m2, Hunter gloss 65-70%, PPS S10 roughness 0.6-1.0 pm, density 1150-1250 kg/ m3, brightness 70-75%, and opacity 89-94%.
Wood free paper is divided into two segments: uncoated and coated. Conventionally, the furnish of wood free papers consists of bleached chemical pulp, with less 25 than 10 % mechanical pulp.
Typical values are for uncoated WFU Copy paper: grammage 70-80 g/m2, Bendtsen roughness 150-250 ml/min and bulk > 1.3 cm3/g; for uncoated offset paper: grammage 60-240 g/m2, Bendtsen roughness 100-200 ml/min and bulk 1.ΣΙ.3 cm3/g; and for color copy paper: grammage 100 g/m2, Bendtsen roughness < 30 50 ml/min and bulk 1.1 cm3/g.
In coated pulp-based printing papers (WFC), the amounts of coating vary widely in accordance with requirements and intended application. The following are typical values for once- and twice-coated, pulp-based printing paper: once-coated basis
20195008 PRH 09 -01- 2019 weight 90 g/ m2, Hunter gloss 65-80%, PPS s10 roughness 0.75-1.1 pm, brightness 80-88%, and opacity 91-94%, and twice-coated basis weight 130 g/ m2, Hunter gloss 70-80%, PPS S10 roughness 0.65-0.95 pm, brightness 83-90%, and opacity 95-97%.
Containerboard includes both linerboard and corrugating medium. Liners are divided according to their furnish base into Kraft liner, recycled liner and white top liner. Liners are typically 1- to 3-ply boards with grammage varying in the range 100-300 g/m2.
Linerboards are generally uncoated, but the production of coated white-top liner is 10 increasing to meet higher demands for printability.
The main cartonboard grades are folding boxboard (FBB), white-lined chipboard (WLC), solid bleached board (SBS) and liquid packaging board (LPB). In general, these grades are typically used for different kinds of packaging of consumer goods. Carton board grades vary from one- up to five-ply boards (150-400 g/m2). 15 The top side is usually coated with from one to three layers (20-40 g/m2); the back side has less coating or no coating at all. There is a wide range of different quality data for the same board grade. FBB has the highest bulk thanks to the mechanical or chemi mechanical pulp used in the middle layer of the base board. The middle layer of WLC consists mainly of recycled fiber, whereas SBS is made from chemi20 cal pulp, exclusively.
FBB’s bulk typically is between 1.1-1.9 cm3/g whereas WLC is on range 1.1-1.6 cm3/g and SBS 0.95-1.3 cm3/g. The PPS-s10-smoothess is respectively for FBB between 0.8 - 2.1 pm, for WLC 1.3- 4.5 pm and for SBS 0.7 - 2.1 pm.
Release paper is used in label base paper in various end-use applications, such 25 as food packaging and office labels. The most common release paper in Europe is supercalendered glassine paper coated with silicone to provide good release properties.
Typical values for supercalendered release papers are basis weight 60 - 95 g/m2, caliper 55-79 pm, IGT 12-15 cm, Cobb Unger for dense side 0.9-1.6 g/m2 and for 30 open side 1.2-2.5 g/m2.
Coated label paper is used as face paper for release, but also for coated backing paper and flexible packings. Coated label paper has a grammage of 60-120 g/m2 and is typically sized or pre-coated with a sizer and single-blade coated on one
20195008 PRH 09 -01- 2019 side. Some typical paper properties for coated and calendered label paper are basis weight 50-100 g/m2, Hunter gloss 70-85%, PPS s10 roughness 0.6-1.0 pm, Bekk smoothness 1500-2000 s and caliper 45-90 pm.
The fiber webs are produced in a fiber web producing process. As known from the 5 prior art in fiber web producing processes typically comprise an assembly formed by a number of apparatus arranged consecutively in the process line. A typical production and treatment line comprises a head box, a wire section and a press section as well as a subsequent drying section and a reel-up. The production and treatment line can further comprise other devices and/or sections for finishing the 10 fiber web, for example, a pre-calender, a sizer, a final-calender, a coating section.
The production and treatment line also typically comprises at least one slitterwinder for forming customer rolls as well as a roll packaging apparatus.
In production of fiber webs, for example in production of paper or board webs, sizing is used to alter the properties of a fiber web by adding sizing agents, for exam15 pie starch or other sizing agents. Sizing can be divided to internal sizing and surface sizing. In internal sizing the sizing agent is added to pulp in the wet end of the fiber web machine before forming. In surface sizing the sizing agent is added onto the surface of the fiber web typically at the dry end of the fiber web machine. Surface sizing is used in production of many fiber web grades, for example of uncoat20 ed fine papers and of several board grades. Sizing is used in order to improve paper web properties, in particular water resistance, water absorption properties, strength, internal strength, surface strength and bending stiffness, as well as to improve adherence of coating color to the surface of the fiber web. In addition, runnability as well as dusting tendency can be affected favorably.
An object of the invention is to create a method of treating a fiber web and a treatment system for treatment of a fiber web, in which the above problems and disadvantages are eliminated or at least minimized.
A particular object of the invention is to create a method and a system to treat the fiber web to improve the surface strength and/or the forming closed fiber web sur30 face.
A particular object is to create a method and a system to treat the fiber web to improve the strength and/or stiffness of the fiber web.
20195008 PRH 09 -01- 2019
To achieve the objects mentioned above and later the method according to the invention is mainly characterized by the features of the characterizing part of the independent method claim.
The treatment system for treatment of a fiber web according to the invention is 5 mainly characterized by the features of the characterizing part of the independent treatment system claim.
Advantageous features and embodiments of the invention are defined in the dependent claims.
According to the invention in the method of treating a fiber web, the fiber web is 10 sized in a sizer, in which the sizing agent is applied onto the fiber web by two sizing rolls in a sizing nip, wherein the fiber web is sized with sizing agent comprising fiber suspension by indirect curtain sizing in a curtain sizer and in the sizing nip at substantially uniform pressure distribution and uniform speed in cross-direction of the fiber web and after the sizing the fiber web is heat-treated in a heat-treatment 15 zone of a heat-treatment device.
According to the invention in the treatment system for treatment of a fiber web, which system comprises a sizer comprising two sizing rolls forming a sizing nip, wherein the system further comprises a heat-treatment device comprising a heattreatment zone and the sizer is a curtain sizer with indirect application of sizing 20 agent comprising fiber suspension and one of the sizing rolls is a deflection compensated roll and a substantially straight sizing nip is formed.
According to one advantageous aspect of the invention the method and the system the fiber web is sized in the curtain sizer and the sizing agent is applied to the fiber web indirectly, i.e. first applying the sizing agent onto a surface of a roll form25 ing a sizing nip, i.e. onto a surface of a sizing roll, and then applying the sizing agent to the fiber web by the sizing roll.
According to an advantageous feature of the invention the curtain sizer comprises a slot or a slide nozzle.
According to an advantageous feature of the invention the fiber web is sized with 30 sizing agent comprising natural fibers and/or synthetic fibers. Advantageously, the sizing agent comprises for example pulp and/or cotton and/or nylon and/or polyester and/or aramid fibers.
20195008 PRH 09 -01- 2019
According to an advantageous feature of the invention the fiber web is sized with sizing agent comprising fiber suspension with 0,5 or less fiber consistency.
According to an advantageous feature of the invention the fiber web is sized with sizing agent having viscosity of 100 cP (centipoise) or over.
Advantageously, length of a fiber in the sizing agent is 0,1 pm - 10 mm and width of a fiber in the sizing agent is 0.01 - 30 pm.
According to an advantageous feature of the invention the fiber web is treated by first adding the sizing agent comprising fiber suspension in the sizer to the fiber web and by thereafter activating the sizing agent by pressure and heat of the heat10 treatment in the heat-treatment zone and thus improving binding of the fiber suspension to the fiber web. Especially, the pressure and the heat of the heattreatment improves the adherence of the fibers of the fiber suspension of the sizing agent onto the surface of the fiber web and thus a very good surface sized fiber web is achieved for application of coating color or other surface finishing sub15 stances onto the fiber web. By this the strength of the fiber web, especially the surface strength of the fiber web, is improved as the Young’s modulus of at least the surface parts of the fiber web with the heat-treated sizing agent increases due to increased and/or enhanced bonding of fibers. The strength of the fiber web after the heat-treatment is improved 10 - 70%. Advantageously, schematical form of 20 the strength variation in thickness direction of the fiber web corresponds to the form of an I-beam cross section form.
According to an advantageous feature of the invention pressure in the sizing nip is at least 4 MPa.
According to one aspect of the invention the method and the system the fiber web 25 after the sizing in the curtain sizer the fiber web is heat-treated in a heat-treatment zone, which is advantageously formed between a heated belt loop, in particularly metal belt loop, and a roll, advantageously a hard roll.
According to one aspect of the invention the method and the system the fiber web after the sizing in the curtain sizer the fiber web is heat-treated in a heat-treatment 30 zone, which is advantageously formed between two belt loops, in particularly metal belt loops, at least one of which is advantageously heated.
According to an advantageous feature of the invention the length of the heattreatment zone is 0,2 - 15 m, advantageously 0,2 -5 m.
20195008 PRH 09 -01- 2019
According to an advantageous feature of the invention the temperature in the heattreatment zone is 100 - 250 QC.
According to an advantageous feature of the invention the pressure in the heattreatment zone is 0,1 MPa - 30 MPa, advantageously 0,1 - 5 MPa. The pressure 5 comprises at least a low basic pressure in the heat-treatment zone but in addition thereto the pressure during the heat-treatment zone can vary, for example at least one high pressure pulse created by at least one additional roll-nip, a heattreatment nip, placed at a location in the heat-treatment zone can be used. Also, instead a loading sector formed by a loading element located in the heat-treatment 10 zone can be used to variate the pressure in the heat-treatment zone.
According to an advantageous feature of the invention the dwell time of the fiber web in the heat-treatment zone is at least 20 ms, advantageously 100 - 10 000 ms.
According to an advantageous feature of the invention the sizing agent is applied 15 in high solids content, preferably in solids content 20 - 40 %.
According to the invention in the treatment system one of the sizing rolls is a deflection compensated roll by which the pressure distribution and speed of the sizing nip can be adjusted in cross-direction of the fiber web and thus substantially uniform speed and uniform pressure distribution in the sizing nip in cross-direction 20 of the fiber web is achieved. Advantageously, the sizing rolls are hard rolls.
According to an advantageous feature of the invention the sizing nip is formed between two hard rolls. Advantageously as the hard roll is used a roll produced of hard material or provided with a hard coating or cover. Advantageously, as the hard roll is used a ceramic or metallic roll or advantageously, a roll with a hard pol25 ymeric roll cover (rubber, polyurethane or composite) having surface hardness 60
- 100 shoreD, advantageously 80 - 95 shoreD. The hard nip enhances the strength increase.
According to an advantageous feature of the invention in the sizing nip of the sizer and thus during the sizing the run of the fiber web is substantially vertical.
According to the invention in the treatment system the sizing nip is formed between two sizing rolls, one of which is a deflection compensated roll and due to the effect provided by the deflection compensated roll the sizing nip is substantially
20195008 PRH 09 -01- 2019 straight, by which the runnability of the fiber web is improved. Advantageously the two sizing rolls are hard sizing rolls.
According to one in particularly advantageous aspect of the invention the method and the system in accordance with the invention are used in production of a fiber 5 web for folding box board or liner fiber web grade.
According to one aspect of invention the system in accordance with the invention are to be by configurating an existing fiber web production line, for example by adding the system to a fiber production line without a sizing section at a location after the drying section, as the sizing section with the heat-treatment zone or by 10 amending an existing sizing section to be in accordance with the treatment system comprising the hard nip sizer with high solids sizing agent and the heat-treatment zone in accordance with the invention.
In the method and in the system according to the invention either one or both sides of the fiber web are treated.
The method and the system according to the invention are also well applicable in sizing with two-component sizing agent as in this type of curtain sizing there is no return circulation of sizing substance. In other types of sizing methods and systems with return circulation the two-component sizing agent may harden in the return circulation and thus cause problems in the return circulation.
The method and the system according to the invention also sizing agents with platy particle shaped substance suspensions, for example kaolin, can be used as in curtain sizing no metering rods are needed for applicating the sizing substance. In types of sizing methods and systems, where metering rods are used, grooves of the metering rods would block if platy particle shaped substance suspensions 25 would be used.
Thus, the sizing agent can also comprise two-component sizing agent, for example lignin with acidic activator, and/or polymers, for example polyethene and/or polypropylene, and/or kaolin in platy particle shape. Also, sizing agents comprising cross-linking substances can be used.
By the invention and its advantageous aspects and features many advantages are achieved, in particular the strength, especially the surface strength, of the fiber web is significantly improved. Additionally, the fiber web with fiber suspension, advantageously with high solids content, content sizing agent has a stiff structure as
20195008 PRH 09 -01- 2019 the sizing agent tends to remain more in the surface parts of the fiber web and the surface pores close and thus need of calendering is decreased. Additionally, the fiber web sized with sizing agent comprising fiber suspension improves the adherence of coating color to the surface of the fiber web.
In the following the invention is further explained in detail with reference to the accompanying drawing in which:
In figures 1 -6 is very schematically shown examples of the treatment system according to the invention.
In the following description same reference signs designate for respective compo10 nents etc. unless otherwise mentioned and it should be understood that the examples are susceptible of modification in order to adapt to different usages and conditions.
In the examples of figures 1-6 is very schematically shown examples of the treatment system in accordance with the invention. In these advantageous examples 15 the fiber web running in direction S substantially upwards is sized in a curtain sizer 10 comprising a sizing nip N formed between two sizing rolls 11,12 sizing agent comprising fiber suspension, advantageously with high solids content, preferably 20 - 40 % solids content, comprising fiber suspension. One of the sizing rolls 11 ;12 is a deflection compensated roll and thus a straight sizing nip is be formed. The 20 sizing rolls 11,12 are advantageously hard rolls. Advantageously, as the hard roll is used a ceramic or metallic roll or advantageously with a hard polymeric roll cover (rubber, polyurethane or composite) having surface hardness 60- 100 shoreD, advantageously 80 - 95 shoreD. Advantageously, pressure in the sizing nip N is at least 4 MPa. A curtain device 14, 15 is located in connection for each sizing roll 25 11, 12 for applying sizing agent T onto the surface of the sizing roll 11,12 and the fiber web W is sized by indirect sizing. The sizing agent T is then via the surface of the sizing roll 11,12 guided onto the surfaces of the fiber web W such that in the sizing nip N the sizing agent is pressed to the fiber web surfaces. After the sizing in the curtain sizer 10 the fiber web W has a short run and via a guide roll 13 is 30 guided to a heat-treatment zone Z of a heat-treatment device 20, where the fiber web W is heat-treated. The heat-treatment zone Z is formed between a belt run of a belt-loop 21 and a roll 22 or between a belt-run of a belt-loop 21 and another belt-run of another belt-loop 24. The length of the heat-treatment zone Z is 0,2 15 m, advantageously 0,2 -5 m, and the temperature in the heat-treatment zone 35 is 100 - 250 QC and the pressure in the heat-treatment zone is 0,1 MPa - 30 MPa,
20195008 PRH 09 -01- 2019 advantageously 0,1 - 5 MPa. The dwell time of the fiber web in the heat-treatment zone Z is at least 20 ms, advantageously 100- 10 000 ms.
In the example of figure 1 the heat-treatment device 20 comprises a belt-loop 21 running and supported by guide rolls 25 and a roll 22 and the heat-treatment zone 5 Z is formed between the run of the belt-loop 21 and the roll 22 on the run of the belt 21 on the roll 22. The fiber web W is guided to run between the belt 21 and the roll 22. Additionally, a heat-treatment nip NZ is formed between the roll 22 and another roll 23 to further press the fiber web W in the heat-treatment zone. In the heat-treatment zone Z the belt 21 is heated.
In the example of figure 2 the heat-treatment device 20 comprises two belt-loops 21,24 running and supported by guide rolls 25, 26 and the heat-treatment zone Z is formed between the runs of the belt-loops 21, 24. The fiber web W is guided to run between the belts 21,24. In the heat-treatment zone Z at least one of the belts 21 is heated.
In the example of figure 3 the heat-treatment device 20 comprises a belt-loop 21 running and supported by guide rolls 25 and a roll 22 and the heat-treatment zone Z is formed between the run of the belt-loop 21 and the roll 22 on the run of the belt 21 on the roll 22. The fiber web W is guided to run between the belt 21 and the roll 22. Additionally, heat-treatment nips NZ are formed between the roll 22 and the guide rolls 25 to further press the fiber web W during its run in the heattreatment zone. In the heat-treatment zone Z the belt 21 is heated.
In the example of figure 4 the heat-treatment device 20 comprises a belt-loop 21 running and supported by guide rolls 25 and a roll 22 and the heat-treatment zone Z is formed between the run of the belt-loop 21 and the roll 22 on the run of the 25 belt 21 on the roll 22. The fiber web W is guided to run between the belt 21 and the roll 22. Additionally, a heat-treatment nip NZ is formed between the roll 22 and the guide rolls 25 to further press the fiber web W during its run in the heattreatment zone. In the heat-treatment zone Z the belt 21 is heated.
In the example of figure 5 the heat-treatment device 20 comprises a belt-loop 21 30 running and supported by guide rolls 25 and a roll 22 and the heat-treatment zone Z is formed between the run of the belt-loop 21 and the roll 22 on the run of the belt 21 on the roll 22. The fiber web W is guided to run between the belt 21 and the roll 22. In the heat-treatment zone Z the belt 21 is heated.
In the example of figure 6 the heat-treatment device 20 comprises a belt-loop 21 running and supported by guide rolls 25 and a roll 22 and the heat-treatment zone Z is formed between the run of the belt-loop 21 and the roll 22 on the run of the belt 21 on the roll 22. The fiber web W is guided to run between the belt 21 and 5 the roll 22. Additionally, a loading element 29 is located in the heat-treatment zone Z to further press in a loading sector LS the fiber web W during its run in the heattreatment zone. In the heat-treatment zone Z the belt 21 is heated.
In the description in the foregoing, although some functions and elements have been described with reference to certain features, those functions and elements 10 may be performable by other features whether described or not. Although features have been described with reference to certain embodiments or examples, those features may also be present in other embodiments or examples whether described or not. Above the invention has been described by referring to some advantageous examples only, to which the invention is not to be narrowly limited. 15 Many modifications and alterations are possible within the inventive idea.
20195008 PRH 09 -01- 2019
20195008 PRH 09 -01- 2019
Reference signs used in the drawing:
sizer sizing roll sizing roll
13 guide roll curtain sizer curtain sizer heat-treatment device
21,24 belt loop
22 roll
25, 26 guide roll loading element
LS loading sector
N size nip
NZ heat-treatment nip
S running direction of the fiber web
T sizing agent
W fiber web
Z heat-treatment zone

Claims (19)

  1. Claims
    1. Method of treating a fiber web, in which method the fiber web is sized in a sizer (10), in which the sizing agent (T) is applied onto the fiber web by two sizing rolls (11,12) in a sizing nip (N), characterized in that the fiber web
    5 (W) is sized with sizing agent (T) comprising fiber suspension by indirect curtain sizing in a curtain sizer (10) and in the sizing nip (N) at substantially uniform pressure distribution and uniform speed in cross-direction of the fiber web (W), and that after the sizing the fiber web (W) is heat-treated in a heat-treatment zone (Z) of a heat-treatment device (20).
    10
  2. 2. Method according to claim 1, characterized in that in the method the fiber web (W) is sized with sizing agent (T) comprising natural fibers and/or synthetic fibers.
  3. 3. Method according to claim 1 or 2, characterized in that in the method the fiber web (W) is sized with sizing agent (T) comprising fiber suspension with
    15 0,5% or less fiber consistency.
  4. 4. Method according to any claims 1 - 3, characterized in that in the method the fiber web (W) is sized with sizing agent (T) having viscosity of 100 cP or over.
  5. 5. Method according to any of claims 1 - 4, characterized in that in the meth-
    20 od the fiber web (W) is sized with high solids sizing agent (T), preferably having solids content of 20 - 40 %.
  6. 6. Method according to any of claims 1 - 5, characterized in that in the method the sizing agent (T) is activated by pressure and heat in the heat- treatment zone (Z) for increasing Young’s modulus of at least surface parts
    25 of the fiber web (W).
  7. 7. Method according to any claims 1 - 6, characterized in that in the heattreatment zone (Z) the fiber web (W) is pressed by a pressure of 0,1 MPa 30 MPa, advantageously of 0,1 - 5 MPa.
  8. 8. Method according to any of claims 1 - 7, characterized in that in the heat30 treatment zone (Z) the temperature is 100 - 250 QC.
    20195008 PRH 09 -01- 2019
  9. 9. Method according to any of claims 1 - 8, characterized in that dwell time of the fiber web (W) in the heat-treatment zone (Z) is at least 20 ms, advantageously 100-10 000 ms.
  10. 10. Method according to any of claims 1 - 9, characterized in that in the heat-
    5 treatment zone (Z) the fiber web (W) is further pressed in at least one heattreatment nip (NZ) or in at least one loading sector (LS).
  11. 11. Method according to any of claims 1-10, characterized in that the sizing agent (T) is applied onto the fiber web by two hard sizing rolls (11,
  12. 12) in the sizing nip (N).
    10 12. Treatment system for treatment of a fiber web, which system comprises a sizer (10) comprising two sizing rolls (11,12) forming a sizing nip (N), characterized in that the system further comprises a heat-treatment device (20) comprising a heat-treatment zone (Z), that the sizer is a curtain sizer (10) with indirect application of sizing agent (T) comprising fiber suspension and 15 that one of the sizing rolls (11 ;12) is a deflection compensated roll and a substantially straight sizing nip (N) is formed.
  13. 13. Treatment system according to claim 8, characterized in that the heattreatment device (20) comprises at least one belt-loop (21), advantageously a heated belt-loop, supported by guide rolls (25), and a roll (22), between of
    20 which at least one belt-loop (21) and roll (22) the heat-treatment zone (Z) of the heat-treatment device (20) is formed.
  14. 14. Treatment system according to any of claim 8 or 9, characterized in that the heat-treatment device (20) comprises two belt-loops (21, 24) supported by guide rolls (25, 26), between or which belt-loops (21,24) the heat-treatment
    25 zone (Z) is formed.
  15. 15. Treatment system according to any of claims 8-10, characterized in that the heat-treatment zone (Z) comprises at least one heat-treatment nip (NZ) or at least one loading sector (LS).
    30
  16. 16. Treatment system according to any of claims 8-11, characterized in that length of the heat-treatment zone (Z) is 0,2-15 m, advantageously 0,2 - 5 m.
  17. 17. Treatment system according to any of claims 8-12, characterized in that temperature in the heat-treatment zone is 100 - 250 QC.
  18. 18. Treatment system according to any of claims 8-13, characterized in that pressure in the heat-treatment zone is 0,1 MPa - 30 MPa, advantageously
    5 of 0,1-5 MPa.
  19. 19. Treatment system according to any of claims 12-18, characterized in that the two sizing rolls forming the sizing nip (N) are hard sizing rolls (11,12).
FI20195008A 2018-08-30 2019-01-09 Method of treating a fiber web and a treatment system for treatment of a fiber web FI20195008A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP19184856.3A EP3617403B1 (en) 2018-08-30 2019-07-08 Method of treating a fiber web and a treatment system for treatment of a fiber web
EP21170343.4A EP3875684B1 (en) 2018-08-30 2019-07-08 Method of treating a fiber web and a treatment system for treatment of a fiber web
CN201910812882.4A CN110872792A (en) 2018-08-30 2019-08-30 Method for treating a fiber web and treatment system for treating a fiber web

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FI20185723A FI20185723A1 (en) 2018-08-30 2018-08-30 Method of treating a fiber web and a treatment system for treatment of a fiber web

Publications (1)

Publication Number Publication Date
FI20195008A1 true FI20195008A1 (en) 2020-03-01

Family

ID=70615206

Family Applications (2)

Application Number Title Priority Date Filing Date
FI20185723A FI20185723A1 (en) 2018-08-30 2018-08-30 Method of treating a fiber web and a treatment system for treatment of a fiber web
FI20195008A FI20195008A1 (en) 2018-08-30 2019-01-09 Method of treating a fiber web and a treatment system for treatment of a fiber web

Family Applications Before (1)

Application Number Title Priority Date Filing Date
FI20185723A FI20185723A1 (en) 2018-08-30 2018-08-30 Method of treating a fiber web and a treatment system for treatment of a fiber web

Country Status (1)

Country Link
FI (2) FI20185723A1 (en)

Also Published As

Publication number Publication date
FI20185723A1 (en) 2020-03-01

Similar Documents

Publication Publication Date Title
EP3875684B1 (en) Method of treating a fiber web and a treatment system for treatment of a fiber web
EP1552058B1 (en) Paper with improved stiffness and bulk and method for making same
EP2682520A1 (en) Method for producing fiber webs and production line for producing fiber webs
US20040180184A1 (en) Coated paper and process for producing same
EP1974096A2 (en) Method of producing coated paper with reduced gloss mottle
US3017295A (en) Coated paper and paperboard and process for making same
EP3988713B1 (en) Method of treating a fiber web and a treatment system for treatment of a fiber web
EP3012371A1 (en) Method of treating a fiber web and a calender for treating a fiber web
US7943010B2 (en) Method of making surface-sized paper/board
EP2725137A1 (en) Method and production line and for producing fiber webs
FI20195008A1 (en) Method of treating a fiber web and a treatment system for treatment of a fiber web
FI122859B (en) Method and device for surface treatment of paper / board
EP3231936B1 (en) Method for producing fiber webs
EP2376708A1 (en) Low density paper and paperboard with two-sided coating
FI128753B (en) Method of treating a fiber web and a treatment system for treatment of a fiber web
US20080289784A1 (en) Method For Treating A Fibrous Web Downstream Of Slitting
FI128040B (en) Method of treating a fiber web and a treatment system for treatment of a fiber web
Sangl et al. Surface sizing and coating
WO2007110472A1 (en) Method and apparatus for producing coated paper or board
EP2876205A1 (en) Method for calendering a fiber web and calender
EP2682521A1 (en) Process and device for treating fiber webs
EP2808444B1 (en) Calender arrangement
WO2012059635A2 (en) Method and apparatus for surface sizing a fibrous web

Legal Events

Date Code Title Description
FD Application lapsed