U.S. patent application number 11/569331 was filed with the patent office on 2008-11-27 for method for treating a fibrous web downstream of slitting.
This patent application is currently assigned to METSO PAPER, INC.. Invention is credited to Jari Ilomaki, Jorma Laapotti, Maria Lepola, Juha Lipponen, Vilho Nissinen, Reijo Pietikainen, Eero Suomi, Risto Talja, Pekka Taskinen, Henri Vaittinen, Mika Viljanmaa.
Application Number | 20080289784 11/569331 |
Document ID | / |
Family ID | 32524617 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080289784 |
Kind Code |
A1 |
Pietikainen; Reijo ; et
al. |
November 27, 2008 |
Method For Treating A Fibrous Web Downstream Of Slitting
Abstract
The invention relates to a method for treating a fibrous web
downstream of slitting. In the method, the finishing of a fibrous
web for providing desired properties is performed by using one or
more finishing units, at least one of which comprises a web
processing apparatus provided with a metal belt.
Inventors: |
Pietikainen; Reijo;
(Jarvenpaa, FI) ; Suomi; Eero; (Hameenlinna,
FI) ; Taskinen; Pekka; (Jyvaskyla, FI) ;
Viljanmaa; Mika; (Helsinki, FI) ; Vaittinen;
Henri; (Jarvenpaa, FI) ; Talja; Risto;
(Vaajakoski, FI) ; Nissinen; Vilho; (Numminen,
FI) ; Laapotti; Jorma; (Palokka, FI) ;
Ilomaki; Jari; (Palokka, FI) ; Lepola; Maria;
(Espoo, FI) ; Lipponen; Juha; (Jarvenpaa,
FI) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA, 101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Assignee: |
METSO PAPER, INC.
Helsinki
FI
|
Family ID: |
32524617 |
Appl. No.: |
11/569331 |
Filed: |
May 31, 2005 |
PCT Filed: |
May 31, 2005 |
PCT NO: |
PCT/FI2005/050184 |
371 Date: |
July 21, 2008 |
Current U.S.
Class: |
162/135 ;
162/205 |
Current CPC
Class: |
D21H 25/14 20130101;
D21G 1/0066 20130101 |
Class at
Publication: |
162/135 ;
162/205 |
International
Class: |
D21F 11/00 20060101
D21F011/00; D21F 3/08 20060101 D21F003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2004 |
FI |
20045243 |
Claims
1. A method for treating a fibrous web downstream of slitting,
characterized in that the finishing of a fibrous web for providing
desired properties is performed in the method by using one or more
finishing units, at least one of which comprises a web processing
apparatus provided with a metal belt, said metal-belt equipped web
processing apparatus used in the method comprising a metal belt
calender and/or a metal belt coater and/or a metal belt dryer
and/or a dry coater, and that the finishing is performed at a
printing site for providing the fibrous web with a desired finish
prior to passing it to a printing press.
2. A method as set forth in claim 1, characterized in that the
method comprises using a common stock to produce various grades for
various applications by varying the running conditions of a metal
belt calender.
3. A method as set forth in claim 1, characterized in that the
method also comprises treating the fibrous web with a metal belt
calender downstream of the printing press for polishing the
print.
4. A method as set forth in any of claims 1 to 3, characterized in
that said one or more finishing units are disposed on-line with
respect to the printing press.
5. A method as set forth in any of claims 1 to 3, characterized in
that said one or more finishing units are disposed off-line with
respect to the printing press.
Description
[0001] The present invention relates to a method for treating a
fibrous web downstream of slitting, said treatment comprising e.g.
calendering, coating or various combinations thereof.
[0002] A wide variety of paper and board grades exist and can be
divided according to basis weight in two classes: papers of a
single ply with a basis weight of 25-300 g/m.sup.2 and boards
produced by multilayer technique with a basis weight of 150-600
g/m.sup.2. As noted, the borderline between paper and board is
floating, the boards with lowest basis weight being lighter than
the heaviest papers.
[0003] The following representative descriptions are examples of
currently employed values for fibrous webs and substantial
deviations from such values are possible. The main source for
descriptions is the publication Papermaking Science and Technology,
section Papermaking Part 3, finishing, edit. Jokio M., publ. Fapet
Oy, Jyvaskyla 1999, page 361.
[0004] Mechanical pulp based or wood containing printing papers
include newsprint, uncoated magazine and coated magazine paper.
[0005] Newsprint consists either entirely of mechanical pulp or may
contain a small amount of bleached softwood pulp (0-15%), and/or
recycled pulp can be used for replacing some of the mechanical
pulp. The following values can probably be considered common for
newsprint: basis weight 40-48.8 g/m.sup.2, ash content (SCAN-P
5:63) 0-20%, PPS s10 roughness (SCAN-P 76-95) 3.0-4.5 .mu.m,
Bendtsen roughness (SCAN-P21:67) 100-200 ml/min, density 600-750
kg/m.sup.3, brightness (ISO 2470:1999) 57-63%, and opacity (ISO
2470:1998) 90-96%.
[0006] Uncoated magazine paper (SC=supercalendered) generally
comprises mechanical pulp at 50-70%, bleached softwood pulp at
10-25%, and fillers at 15-30%. Typical values for calendered SC
paper (including, among others, SC-C, SOB and SC-A/A+) are basis
weight of 40-60 g/m.sup.2, ash content (SCAN-P 5:63) of 0-35%,
Hunter gloss (ISO/DIS8254/1) of <20-50%, PPS s10 roughness
(SCAN-P 76:95) of 1.0-2.5 .mu.m, density of 700-1250 kg/m.sup.3,
brightness (ISO 2470:1999) of 62-70%, and opacity (ISO 2470:1998)
of 90-95%.
[0007] Table 1 presents typical values for mechanical pulp
containing, coatable papers. (MFC=machine finished coated, FOO=film
coated offset, LWC=light weight coated, MWC=medium weight coated,
HWC=heavy weight coated).
TABLE-US-00001 TABLE 1 MFC FCO LWC MWC HWC basis weight 50-70 40-70
40-70 70-90 100-135 (g/m.sup.2) Hunter gloss 25-40 45-55 50-65
65-70 (ISO/DIS 8254/1), (%) PPS-s10 2.2-2.8 1.5-2.0 0.8-1.5 0.6-1.0
roughness, (.mu.m) (offset) (SCAN-P 76/95) 0.6-1.0 (roto) density,
(kg/m.sup.3) 900-950 1000-1050 1100-1250 1150-1250 brightness (ISO
70-75 70-75 70-75 70-75 2470: 1999), (%) opacity 91-95 91-95 89-94
89-94 (ISO 2470: 1998), (%)
[0008] Coated magazine paper (LWC=light weight coated) contains
mechanical pulp at 40-60%, bleached softwood pulp at 25-40%, and
fillers and coating agents at 20-35%.
[0009] HWC can be coated even more than twice.
[0010] Woodfree printing papers made of chemical pulp or fine grade
papers include uncoated- and coated-chemical pulp based printing
papers, in which the fraction of mechanical pulp is less than
10%.
[0011] Uncoated printing papers based on chemical pulp (WFU)
contain bleached birchwood pulp at 55-80%, bleached softwood pulp
at 0-30%, and fillers at 10-30%. WFU shows wide fluctuation of
values: basis weight 50-90 g/m.sup.2 (even up to 240 g/m.sup.2),
Bendtsen roughness 250-400 ml/min, brightness 86-92%, and opacity
83-98%.
[0012] Coated printing papers based on chemical pulp (WFC) have
coatings fluctuate over a wide range according to requirements and
application. The following are typical values for once and twice
coated printing paper based on chemical pulp: once coated basis
weight 90 g/m.sup.2, Hunter gloss 65-80%, PPS s10 roughness
0.75-2.2 .mu.m, brightness 80-88%, and opacity 91-94%, and twice
coated basis weight 130 g/m.sup.2, Hunter gloss 70-80%, PPS s10
roughness 0.65-0.95 .mu.m, brightness 83-90%, and opacity
95-97%.
[0013] Other papers include, among others, sackkraft, tissue, and
wallpaper.
[0014] Board making is performed by using chemical pulp, mechanical
pulp and/or recycled pulp. Board grades can be divided e.g. in the
following main groups according to applications intended
therefor.
[0015] Corrugated board including a liner and a fluting.
[0016] Boxboards used for making boxes, containers. Boxboards
include, among others, liquid packaging boards (FBB=folding
boxboard, LPB=liquid packaging board, WLC=white-lined chipboard,
SBS=solid bleached sulfite, SUS=solid unbleached sulfite).
[0017] Graphic boards used for making e.g. cards, folders, files,
cases, covers, etc.
[0018] As indicated by the foregoing, there is a huge variety of
paper and board grades and machines of several different types are
used for making the same.
[0019] It is an objective of the present invention to provide a
method and apparatus for treating coated and uncoated papers and
boards in an optimal manner in a process following the actual
manufacturing line downstream of slitting, the webs to be treated
being narrow, e.g. 0.15-4.5 m, the size of finishing machines being
thus designed respectively to be substantially smaller than the
processing equipment normally present in the manufacturing
line.
[0020] In order to accomplish the objectives of the invention, a
method of the invention is characterized by what is set forth in
the characterizing clause of claim 1. In the method, the treatment
of a fibrous web for providing desired properties is performed e.g.
at a printing site, prior to passing the fibrous web to a printing
press, by using one or more finishing units, at least one of which
is a metal-belt equipped web processing apparatus, e.g. a metal
belt calender, a coater, a dryer, a dry coater or the like.
[0021] A metal belt calender, which allows for the use of a very
extensive pressure range and application time (heat transfer time
and/or treating time) in a treatment zone, one and the same
apparatus being applicable for the treatment of numerous different
coated and uncoated printing papers and boards, has been described
in more detail e.g. in earlier applications PCT/FI03/00066,
PCT/FI03/00067 and PCT/FI03/00068 of the applicant for present
application, and thus it is not described further at this time. In
a metal belt calender, the length of a treatment zone is determined
by means of the disposition of belt guiding elements and/or the
design and/or disposition of counter-elements, and the contact
pressure applied to a web within the treatment zone can be made
adjustable for example within the range of about 0.01 MPa to about
200 MPa.
[0022] The size of a metal belt calender can be made smaller when
using it the treatment of rolled-up narrow fibrous webs adapted to
the width of a printing press or some other further processing
machine. The use of a metal belt calender enables a rapid change of
treatment conditions, allowing e.g. for the manufacture of paper
and board grades for different applications on the basis of one and
the same stock, said stock possibly consisting of a coated or
uncoated web of paper or board. Hence, a switch between grades can
be implemented readily and quickly, enabling the manufacture of
even small batches in a cost effective fashion. In addition, the
stock purchase costs of a printing house will be reduced.
[0023] Furthermore, metal belt calendering stabilizes the structure
of a fibrous web, enabling the minimization of bubbling in a
printing press resulting from the use of a water-soluble printing
ink.
[0024] A method of the invention can also be accompanied by a
relatively light treatment of the printed fibrous web with a metal
belt calender downstream of the printing press, if such treatment
is beneficial for polishing the print.
[0025] In association with a metal belt calender can also be
provided elements for coating a fibrous web, such as for example a
dry coating apparatus or a separate coater, upstream or downstream
of the metal belt calender. In association with a printing press
can be provided not only metal belt calenders but also other types
of calenders for enabling a versatile treatment of the fibrous web
prior to passing it to the printing press.
[0026] A metal belt calender can also be used for drying a fibrous
web, thus enabling the use of a higher rolling-up moisture on the
papermaking line.
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