U.S. patent application number 10/747810 was filed with the patent office on 2004-10-14 for printing paper and a method for manufacturing the same.
This patent application is currently assigned to UPM-Kymmene Corporation. Invention is credited to Aho, Pekka, Koskinen, Timo, Sarela, Seppo.
Application Number | 20040200593 10/747810 |
Document ID | / |
Family ID | 8561557 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040200593 |
Kind Code |
A1 |
Koskinen, Timo ; et
al. |
October 14, 2004 |
Printing paper and a method for manufacturing the same
Abstract
In the method for manufacturing printing paper the base paper of
the printing paper contains mechanical pulp and/or recycled fibre.
The method also comprises the surface sizing and calendering of the
base paper. In the method the base paper is calendered before
surface sizing in a calender that comprises at least one nip that
is formed between a hard-faced roll and a soft counter surface. The
invention also relates to a printing paper manufactured by means of
the method.
Inventors: |
Koskinen, Timo; (Grand
Rapids, MN) ; Aho, Pekka; (Jamsankoski, FI) ;
Sarela, Seppo; (Valkeakoski, FI) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
UPM-Kymmene Corporation
|
Family ID: |
8561557 |
Appl. No.: |
10/747810 |
Filed: |
December 29, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10747810 |
Dec 29, 2003 |
|
|
|
PCT/FI02/00580 |
Jun 28, 2002 |
|
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Current U.S.
Class: |
162/205 ;
162/135; 162/158 |
Current CPC
Class: |
D21H 11/14 20130101;
D21G 1/00 20130101; D21H 21/16 20130101; D21H 11/08 20130101; D21H
23/30 20130101 |
Class at
Publication: |
162/205 ;
162/158; 162/135 |
International
Class: |
D21H 021/16; D21H
023/22; D21H 025/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2001 |
FI |
20011429 |
Claims
What is claimed is:
1. A method for the manufacture of surface-sized printing paper,
the base paper of said printing paper containing mechanical pulp
and/or recycled fibre, and said method comprises the surface sizing
and calendering of the base paper, wherein the base paper is
calendered before surface sizing in a calender comprising at least
one nip that is formed between a roll with a hard surface and a
soft counter surface.
2. The method according to claim 1, wherein the base paper is
calendered before surface sizing in a supercalender or multinip
calender.
3. The method according to claim 1 or 2, wherein the base paper is
calendered before surface sizing in such a manner that the PPS-10
surface roughness of the same after calendering and before surface
sizing is advantageously 1.0 to 1.3 .mu.m .
4. The method according to any of the preceding claims, wherein
after calendering the base paper is surface sized with a surface
sizing agent, the amount of the surface sizing agent being 3
g/m.sup.2 per side.
5. The method according to claim 4 wherein the amount of surface
sizing agent is under 2 g/m.sup.2 per side.
6. The method according to claim 3 wherein the amount of surface
sizing agent is 0.5 to 1.5 g/m.sup.2 per side.
7. The method according to claim 3, wherein in that the base paper
is surface sized on both sides.
8. The method according to claim 3, wherein after surface sizing
the base paper is calendered in a calender having one or two
nips.
9. The method according to claim 8 wherein in that after surface
sizing the base paper is calendered in a calender that comprises a
nip that is formed between a hard-faced roll and a soft-faced
roll.
10. A surface-sized printing paper in which the base paper contains
mechanical pulp and/or recycled fibre and filler 10 to 40% by
weight of the total fibre content, the surface roughness of said
printing paper being 2.0 .mu.m at the highest, wherein the amount
of surface sizing agent is under 2.0 g/m.sup.2 per side when
calculated in dry matter.
11. The printing paper according to claim 10, wherein the amount of
surface sizing agent is 0.5 to 1.5 g/m.sup.2 per side.
12. The printing paper according to claim 10 or 11, wherein the
printing paper is surface sized on both sides.
Description
[0001] The present invention relates to a method for manufacturing
a printing paper. The method comprises the surface sizing and
calendering of base paper containing mechanical pulp and/or
recycled fibre. The invention also relates to surface-sized
printing paper, in which the base paper contains mechanical pulp
and/or recycled fibre and filler 10 to 40 wt-% of the total fibre
content, the surface roughness of the printing paper being 2.0
.mu.m at the highest (PPS-10 method).
BACKGROUND
[0002] Publication U.S. Pat. No. 3,982,056 discloses a paper coated
on one side, the printability of which paper is improved by
moistening the uncoated side of the paper and conveying the paper
thereafter to a gloss calender, in which the coated side is brought
in contact with the smooth surface of a hot roll. The aim is to
obtain printing properties of similar quality than those of
supercalendered paper.
[0003] Publication U.S. Pat. No. 6,013,359 discloses a printing
paper, especially a newsprint coated either with polyacrylamide or
acrylamide/metacrylamide copolymer. The amount of coating is 0.01
to 0.2 g/m.sup.2 per side. After the coating process the paper is
supercalendered.
[0004] It is a problem of known coated printing papers such as LWC
papers that the raw material base is expensive because of large
amount of pulp that is necessary and the large amount of coating
material. The use of printing papers with less expensive raw
material base is, in turn, restricted by the fact that the print
does not have the desired quality. When supercalendered paper (SC)
is used as printing paper the screen dots in the areas between the
fibres are not repeated in a sufficiently intact state. This can be
affected by calendering the paper more efficiently, but this can
result in blackening by calendering and/or clusters of screen dots
i.e. so-called galvanized print.
SUMMARY
[0005] By means of the printing paper and method according to the
invention for the manufacture of the same, it is possible to avoid
the above-mentioned problems. The printing paper according to the
invention is characterized in that the amount of surface treatment
agent is under 2.0 g/m.sup.2 per side. The method according to the
invention is characterized in that the base paper is calendered
before surface sizing in a calender that comprises at least one nip
that is formed between a hard-faced roll and a soft-faced roll.
[0006] By means of the method according to the invention a priting
paper is attained the properties of which are better than those of
conventional supercalendered paper, and the paper according to the
invention can be utilized to replace known coated paper grades,
such as LWC paper. The printing paper according to the invention
can be printed by offset with printing inks used in connection with
LWC papers. It is also possible to use so-called dry offset method
when printing said paper. The above-mentioned advantages of
printing paper are mainly based on the good dry surface strength of
paper attained by means of the method according to the invention.
When compared to other coated papers, the consumption of the
surface treatment agent is very small. As a result of the
aforementioned fact the need for drying the paper is very small as
well. The advantage of gravure papers is that the pores of the
printing paper manufactured with the method according to the
invention are closed in such a manner that the evenness of
absorption of the printing ink is improved.
[0007] As coated printing papers can be at least partly replaced
with uncoated, surface-sized printing paper manufactured by means
of the method according to the invention, investments in the
papermaking line in connection with surface sizing are small when
compared to investments required by coated printing papers.
[0008] The basic idea of the method according to the invention is
to calender the base paper before coating the same with the surface
sizing agent so that the base paper obtains such a smooth and
pore-free structure that as small amount of surface sizing agent as
possible is consumed, and nevertheless, a printing paper with good
printing properties is obtained. The paper according to the
invention can be used both as an offset paper and gravure
paper.
DETAILED DESCRIPTION
[0009] Paper with surface roughness of 5.0 to 7.5 .mu.m when
measured with the PPS-10 method is used as base paper. The raw
material content of the base paper can correspond to typical
supercalendered (SC) printing paper. The fibre content of the base
paper is typically 70 to 90% by weight of mechanical pulp, such as
groundwood or refiner groundwood, and 10 to 30% by weight of pulp.
Part of the mechanical pulp can be replaced with recycled fibres.
The fibre content can contain 15 to 40% by weight of filler, such
as clay mineral, talc or calcium carbonate. The grammage typically
varies between 39 to 80 g/m.sup.2.
[0010] The base paper can also be such paper that comprises
mechanical pulp and/or recycled fibre over 90% by weight,
advantageously over 95% by weight of the total fibre content of
paper. The fibre content of the base paper may also consist
entirely of mechanical pulp and/or recycled fibre. Because the use
of chemical pulp in paper improves for example the strength
properties of the paper, the use of fillers, in turn, weakens the
paper, as the amount of chemical pulp is reduced, the amount of
filler is advantageously also smaller, for example 10 to 15% by
weight of the fibre content.
[0011] The base paper is calendered before it is coated with the
surface sizing agent in such a manner that the surface roughness is
typically 1.0 to 1.3 .mu.m. The calendered base paper is coated
with a surface sizing agent that is used 3.0 g/m.sup.2 per side,
advantageously under 2.0 g/m.sup.2 per side, most advantageously
0.5 to 1.5 g/m.sup.2 per side. The amount of 0.5 g/m.sup.2 per side
is not necessarily the minimum value of the most advantageous area,
but the minimum value can be even 0.3 g/m.sup.2 per side.
Advantageous results have been attained for example in the range of
0.3 to 1.0 g/m.sup.2 per side. The presented amounts of surface
sizing agent represent dry matter contents.
[0012] In the method according to the invention the base paper is
first treated with a calendering treatment to reduce the surface
roughness. Thereafter the base paper is surface sized with a
surface sizing agent, and the attained surface-sized paper is
calendered again lightly so that a suitable smoothness of the
surface is attained after the surface sizing. The surface sizing
agent is substantially free of mineral substances, such as
kaolin.
[0013] Suitable surface sizing agents include water-soluble
adhesives, such as carboxy-methyl cellulose (CMC) or starch,
different kinds of latexes, different kinds of waxes and mixtures
of the above-mentioned agents. Especially the mixtures of starch
and some other agents such as plastic pigments (for example
styrene/acrylic copolymer particles, particle diameter 1.0 .mu.m,
such as Ropaque HP-1055, Rohm & Haas), styrene/acrylate latex
or styrene/butadiene latex are especially advantageous in relation
to the printability of offset paper. For offset printing paper
starch is an especially advantageous option as a surface sizing
agent.
[0014] The base paper is calendered before it is surface sized with
the surface sizing agent in a calender with more than one nip. The
calender comprises at least one nip that is formed between a
hard-faced roll and a soft counter surface. The hard-faced roll is
typically a heated metal roll. The soft counter surface can be for
example a roll with a paper surface, a roll with an elastic
surface, a belt or a shoe roll. The surface of an elastic roll is
typically composed of a polymer surface.
[0015] Advantageously the calendering is conducted in a
supercalender or multinip calender. In connection with the
calendering it is possible to moisten the paper with steam or by
spraying water. The term supercalender refers to a calender with
several nips in which hard and soft rolls alternate. The
supercalender may also contain nips, typically only one, in which
the nip is composed between two soft-faced rolls. The soft roll can
be a roll with a paper surface (filled roll), or a resilient roll
with a polymer surface. The same calender may contain both rolls
with a paper surface and rolls with a polymer surface. The
supercalender typically comprises 9 to 12 rolls. The supercalender
is typically an off-line calender.
[0016] The term multinip calender refers to calenders that contain
several nips and that comprise nips formed between a hard-faced
heated roll and a roll with an elastic surface. The roll with an
elastic surface is typically a polymer coated roll. The multinip
calenders can be on-line or off-line calenders. Such calenders
include for example Janus calenders (Voith-Sulzer) Prosoft
calenders (Kusters-Beloit) ans OptiLoad calenders (Metso
Paper).
[0017] After calendering the base paper whose surface roughness
after calendering is typically 1.0 to 1.3 .mu.m, is surface sized
with a surface sizing agent. The surface sizing is typically
two-sided. The surface sizing is advantageously conducted as film
coating. The concept of film coating refers to all such methods in
which a determined amount of surface sizing agent is portioned in a
suitable manner on the surface or the roll, and the surface sizing
agent is transferred from the surface of the roll on the surface of
the base paper. Another alternative is spray coating, and
surprisingly, it was detected that blade coating is also suitable
to be used in the method according to the invention, although
earlier it was not possible to use blade coating in surface sizing
by methods of prior art because of the tendency of the web to
break. Gravure coating is also a suitable method.
[0018] After surface sizing the printing paper is dried and
calendered to restore the smoothness of the surface after surface
sizing, advantageously the printing paper is treated lightly in a
calender with one or two nips. The calender advantageoulsy
comprises a nip that is formed between a hard-faced roll and a
soft-faced roll.
[0019] The manufacturing line of the printing paper according to
the invention can be for example the following. The base paper can
consist of normal supercalendered paper (SC) which has already been
treated in a supercalender or in a multinip calender into a
suitable surface roughness. The base paper is unwound from the reel
in the beginning of the surface sizing line and it is surface sized
with a surface sizing agent for example in a film coating unit or
blade coating unit. The surface sizing agent is dried and the
printing paper is calendered in a calender with one or two nips.
Thereafter the printing paper that is surface-sized with surface
sizing agent is reeled up.
[0020] The devices necessary for surface sizing and drying can also
be added in connection with the calender. Thus, the calendered
paper is conveyed from the calender to the surface sizing and
drying, whereafter it is calendered lightly in a calender with one
or two nips.
[0021] By means of the method according to the invention printing
paper with a maximum surface roughness of 2.0 .mu.m is
advantageously manufactured. Typically, the surface roughness is
under 2.0 .mu.m, advantageously it is 1.0 to 1.2 .mu.m. The density
of printing paper is typically at least 900 kg/m.sup.3. The
aforementioned numerical values refer to the results obtained by
means of the following test methods:
1 surface roughness SCAN-P 76:95 density SCAN-P 7:96
[0022] In the following, the invention will be described by means
of examples. The results presented in the examples have been
obtained with the test methods listed below.
2 Conditioning of sheets SCAN-P 2:75 Grammage SCAN-P 6:75 Moisture
content SCAN-P 4:63 Thickness SCAN-P 7:96 Density SCAN-P 7:96 Ash
(925.degree. C.) SCAN-P 5:63 Air permeance (Bendtsen) SCAN-P 60:87
Roughness (Bendtsen) SCAN-P 21:67 Roughness (PPS) SCAN-P 76:95
Elongation SCAN-P 38:80 Tear index SCAN-P 11:96 Dry surface
strength (IGT) SCAN-P 63:90 Printing ink absorption (K&N)
SCAN-P 70:95 Oil absorption (Unger) SCAN-P 37:77 Gloss TAPPI T480
OS-78 ISO brightness SCAN-P 3:93 Opacity SCAN-P 8:93 Y-value SCAN-P
8:93 Light scattering coefficient SCAN-P 8:93 Absorption
coefficient SCAN-P 8:93 Water penetration speed (Emco) Measurement
device of dynamic penetration, as a measurement result the greatest
relative change in the transmission of ultrasound
EXAMPLE 1
Offset Printing Papers
[0023] The properties of offset printing papers were examined in
printing papers that were surface sized with a surface sizing agent
before calendering and from printing papers calendered before
coating with a surface sizing agent. The samples were produced
under laboratory conditions. In samples O1 to O8 that are examples
of papers surface sized with a surface sizing agent before
calendering, uncalendered paper was used as base paper. After
surface sizing the paper was calendered in a laboratory calender
simulating supercalendering. The laboratory calender was a calender
that comprised a nip formed between a hard heated roll and a soft
paper roll. The calendering humidity was 8.5 to 9.0%, the number of
nips was 8, the temperature of the heated rolls 75.degree. and the
nip pressure 200 kN/m.
[0024] In the samples O1 and O2 aqueous acrylic copolymer
dispersion (Basoplast 335 D, BASF AG) was used as surface sizing
agent, in samples O3 and O4 carboxy-methyl cellulose (in sample O3
Finnfix 10, Noviant Oy, in sample O4 Finnfix 5, Noviant Oy), in
samples O5 ja O6 starch (Raisamyl 404N, Raisio Chemicals Oy) ja in
samples O7 ja O8 cationic wax dispersion (Raibond 23 CA, Raisio
Chemicals Oy). The test results are shown in Table 1.
[0025] In samples O9 to O16 that are examples of papers surface
sized with a surface sizing agent after calendering, calendered
paper was used as base paper. After coating the paper was
calendered only lightly. The calendering humidity was 5.5 to 6.0%,
the number of nips was 2, the temperature of the heated rolls
75.degree. C. and the nip pressure 200 kN/m.
[0026] The surface sizing agents were in sample O9 aqueous acrylic
copolymer dispersion (Basoplast 335 D, BASF AG), in sample O10
carboxy-methyl cellulose (Finnfix 5, Noviant Oy), in sample O11
starch (Raisamyl 404 N, Raisio Chemicals Oy), in sample O12
cationic wax dispersion (Raibond 23 CA, Raisio Chemicals Oy), in
sample O13 a mixture of carboxy-methyl cellulose and acrylic
copolymer dispersion (Finnfix 5 and Basoplast 335 D), in sample O14
a mixture of starch and acrylic copolymer dispersion (Raisamyl 404
N and Basoplast 335 D), in sample O15 a mixture of starch and
styrene acrylate latex (Raisamyl 404 N and XZ 94329.02, DOW Oy) and
in sample O16 a mixture of starch and styrene butadiene latex
(Raisamyl 404 N and DL 966, DOW Oy). The test results are shown in
Table 2.
[0027] In printing papers that were calendered before surface
sizing, a smoother surface was attained than in paper manufactured
in the conventional manner by using smaller amounts of surface
sizing agent, compare for example the amounts of surface sizing
agents and PPS 10 surface roughness values in samples O1, O2 and
O9, in samples O4 and O10, in samples O5, O6 and O11 and samples
O7, O8 and O12. By examining the above-mentioned samples it is also
possible to notice that the absorption of the printing ink is in
samples calendered before surface sizing on the same level than in
samples surface sized without calendering, although the used
amounts of surface sizing agent are multiple in the samples surface
sized without calendering when compared to samples calendered
before surface sizing.
EXAMPLE 2
Offset Printing Papers
[0028] The printing properties of offset printing papers
manufactured by means of the method according to the invention were
examined in samples manufactured in pilot scale. The base paper in
the samples OP1 to OP16 was supercalendered 56 g/m.sup.2 paper.
[0029] The samples Ref. 1 and Ref. 2 are reference samples. Ref. 1
is LWC paper intended for offset printing and Ref. 2 is SC paper
intended for offset printing. In samples OP1 and OP2 the surface
treatment agent is wax dispersion (Raibond 35 CA), in samples OP3
and OP4 carboxy-methyl cellulose (Finnfix 5), in samples OP5 and
OP6 cationic surface sizing starch (Raisamyl 404 N), in samples OP7
and OP8 a mixture of starch and acrylic copolymer dispersion in a
ratio of 80/20% by weight (Raisamyl 404 N and Basoplast 335 D), in
samples OP9 and OP10 a mixture of starch and styrene/butadiene
latex in a ratio of 80/20% by weight (Raisamyl 404 N and DL 966),
in samples OP11 ja OP12 a mixture of starch and styrene/acrylate
latex in a ratio of 80/20% by weight (Raisamyl 404 N and XZ
94329.02), in samples OP13 ja OP14 a mixture of caboxy-methyl
cellulose and acrylic copolymer dispersion in a ratio of 80/20% by
weight (Finnfix 5 and Basoplast 335 D) and in samples OP15 and OP16
a mixture of starch and plastic pigment in a ratio of 80/20% by
weight (Raisamyl 404 N and Ropaque HP 1055). The test results are
shown in Table 3.
[0030] The results show that the dry surface strenght values were
increased in all surface sizing agents that were used when compared
to the reference samples. Most of the surface treatment agents
reduced the ink requirement, increased the tone value of the print
and decelerated the penatration of water in the paper.
EXAMPLE 3
Gravure Papers
[0031] Properties of gravure papers were examined in the reference
samples and in samples that were calendered before surface
sizing.
[0032] Samples Ref. 3 and Ref. 4 and Ref. 5 are reference samples
that are manufactured by conventional methods to be used as gravure
papers. Ref 3 is 52 g/m.sup.2 SC-paper, Ref.4 is 56 g/m.sup.2
SC-paper and Ref.5 is 51 g/m.sup.2 LWC-paper.
[0033] The base paper in the samples R1 to R6 according to the
invention was 52 g/m.sup.2 supercalendered paper, the surface
roughness (PPS 10) of which was .apprxeq.1.14 .mu.m. When the base
paper had been surface sized, it was calendered under laboratory
conditions to obtain the same surface roughness (PPS 10) than in
supercalendered gravure papers (Gradek laboratory calender). The
paper was calendered in two nips, the temperature was 75.degree. C.
and the pressure 4 MPa. The moisture content of the paper before
calendering was .apprxeq.6%.
[0034] The paper was surface sized in a blade coating unit in a
laboratory in such a manner that only one side of the paper was
surface sized. In sample R1 the surface sizing agent was only
water, in sample R2 carboxy-methyl cellolose (Finnfix 5, Noviant
Oy), in sample R3 cationic wax dispersion (Raibond 35 CA, Raisio
Chemicals Oy), in sample R4 a mixture of carboxy-methyl cellulose
and cationic wax dispersion (Finnfix 5 and Raibond 35 CA in a ratio
of 50%/50%), in sample R5 a mixture of carboxy-methyl cellulose
(Finnfix 5) and polyethylene glykol in a ratio of 50%/50% and in
sample R6 a mixture of carboxy methyl cellulose (Finnfix 5) and
basic paste in a ratio of 50%/50%. The basic paste contains 55
parts of talc, 45 parts of kaoline and 5.5 parts of polyvinyl
acetate acrylate latex, in which the acrylate is butylacrylate
(Raisional 388, Raisio Chemicals Oy). The target pH in the surface
treatment agent of sample R6 was 9.5. The results of the tests are
shown in tables 4 to 6.
[0035] The absorption values of the printing paper manufactured by
means of the method according to the invention were considerably
reduced when compared to the reference sample. The reduction in the
values was at least 75%.
[0036] The tensile index remained the same or improved slightly
when compared to conventional supercalendered gravure paper, the
tensile energy absorption index, in turn, was significantly
improved. The tear index was dependent on the surface sizing agent
that was used, and it was at its highest when cationic wax
dispersion was used as surface sizing agent, said wax dispersion
being an aqueous mixture of starch and calcium stearate. The amount
of starch in the wax dispersion was 10%.
[0037] The effect of the surface sizing agent on the optical
properties was monitored by measuring brightness and opacity. The
brightness was dependent on the chemical that was used. The surface
sizing agent did not have much effect on opacity.
[0038] Table 6 shows the results of the printability of the
printing paper according to the invention. In gravure tests a GRI
gravure machine, Shell Cup S2 ink viscosity measurement and black
test ink (Sun Chemical) were used.
[0039] The printing ink was manufactured in such a manner that 700
ml of toluene was added in 1800 grammes of test ink supplied by the
factory. The viscosity was measured with a viscometer and time
measurement. The time should be 25 seconds.
[0040] The printing ink was poured in a water container. The sample
was attached on a printing base and it was printed.
[0041] The results show that the tone level of the printing ink and
the gloss of the print are improved when the method according to
the invention is used in the manufacture. The amount of missing
dots largely depends on the surface sizing agent that is used. The
structure of the paper coated with surface sizing agent is very
closed, because print through is reduced. The results obtained from
the air permeance, water penetration speed and printing ink
absorption also refer to the closed quality of the surface. The act
of supplementing the sample R6 with a mineral agent did not result
in considerable advantages in the printing properties.
[0042] The invention is not restricted to the description above,
but it may vary within the scope of the claims. The main aspect in
the present invention is that by calendering the base paper
sufficiently before surface sizing in such a manner that a
permanent change in the surface roughness is attained, it is
possible to attain printing paper with good quality with only a
small amount of surface sizing agent. By means of selecting a
suitable surface sizing agent it is possible to make the printing
paper suitable for offset or gravure printing.
EXAMPLE 1
Properties of Surface-Sized and Calendered Offset Printing
Paper
[0043]
3 Property O1 O2 O3 O4 O5 O6 O7 O8 Amount of surface sizing agent
(g/m.sup.2) 0.7 3.5 0.6 2.4 1.8 4.3 0.8 3.7 Grammage (g/m.sup.2)
58.2 60.6 57.4 59.6 59.1 61.6 58.3 60.8 Thickness (.mu.m) 56.0 54.3
46.0 47.0 47.4 48.3 47.6 47.6 Bulk (m.sup.3/kg) 0.96 0.90 0.80 0.79
0.80 0.78 0.82 0.78 Density (kg/m.sup.3) 1040 1116 1249 1268 1246
1275 1226 1277 Roughness (Bendtsen), top surface (ml/min) 31 19 33
33 31 18 40 23 Air permeance (Bendtsen) (ml/min) 9 1 3 1 1 1 3 1
Gloss, top surface (%) 33.8 44.2 38.4 45.3 51.1 65.6 39.6 43.4
Roughness (PPS-10), top surface (.mu.m) 1.96 1.66 1.44 1.38 1.22
1.21 1.33 1.16 Printing ink absorption (K&N), top surface (%)
8.8 5.6 10.9 6.1 5.0 3.2 8.6 4.0 Oil absorption, top surface
(g/m.sup.2) 1.23 0.73 1.08 0.80 0.43 0.08 1.10 0.30 Water
penetration speed (Emco), S value (%) r/s 8.3 2.0 35.0 14.8 12.5
7.0 20.0 13.3 Dry surface strength (IGT), medium-viscous oil, top
0.38 0.35 0.55 0.64 0.68 0.36 0.63 0.80 surface (m/s) Dry surface
strength (IGT), low-viscous oil, top 2.07 1.66 2.65 4.00 3.58 2.53
2.11 3.52 surface (m/s) ISO brightness, top surface (%) 66.6 61.9
66.6 64.9 64.9 64.6 67.3 65.9 Dominant wavelength, top surface (nm)
573.0 573.0 572.0 573.0 572.0 572.0 573.0 574.0 Ink purity, top
surface (%) 5.9 7.7 4.0 4.2 4.3 4.1 3.8 3.9 Y value, top surface
(%) 72.8 69.8 70.6 68.9 69.1 68.6 71.0 69.6 Opacity, top surface
(%) 94.0 92.5 90.8 90.8 90.5 91.1 91.5 91.6 Light scattering
coefficient, top surface (m.sup.2/kg) 56.7 44.8 43.8 40.0 40.1 39.1
45.3 42.0 Absorption coefficient, top surface (m.sup.2/kg) 2.88
2.94 2.68 2.81 2.78 2.81 2.69 2.79
[0044]
4TABLE 2 Properties of calendered and surface-sized printing paper
Property O9 O10 O11 O12 O13 O14 O15 O16 Amount of surface sizing
agent (g/m.sup.2) 0.4 0.4 0.3 0.4 0.5 0.8 1.0 0.8 Grammage
(g/m.sup.2) 56.8 56.8 56.1 57.2 57.1 57.6 57.2 57.1 Thickness
(.mu.m) 48.0 46.0 46.0 46.0 45.5 45.7 46.3 48.0 Bulk (m.sup.3/kg)
0.84 0.81 0.82 0.80 0.80 0.79 0.81 0.84 Density (kg/m.sup.3) 1184
1234 1220 1243 1254 1260 1236 1189 Roughness (Bendtsen), top
surface (ml/min) 21 17 17 20 19 12 13 18 Air permeance (Bendtsen)
(ml/min) 2 7 4 7 0 0 1 1 Gloss, top surface (%) 48.6 50.2 52.5 49.9
51.8 62.8 64.0 63.1 Roughness (PPS-10), top surface (.mu.m) 1.12
1.06 0.99 0.99 1.08 1.11 1.06 1.06 Printing ink absorption
(K&N), top surface (%) 5.6 8.4 5.6 11.4 5.8 3.4 4.2 3.5 Oil
absorption, top surface (g/m.sup.2) 0.73 1.20 -- 1.68 0.40 0.20
0.20 0.30 Water penetration speed (Emco), S value (%) r/s 21.0 56.0
56.0 73.0 18.9 7.5 7.7 7.3 Dry surface strength (IGT), low-viscous
oil, lop surface 1.13 1.54 1.66 1.30 3.35 2.96 2.47 3.00 (m/s) ISO
brightness, top surface (%) 66.0 66.4 66.4 66.7 65.6 64.3 65.0 64.7
Dominant wavelength, top surface (nm) 572.0 572.0 572.0 572.0 572.1
572.1 571.8 571.8 Ink purity, top surface (%) 5.1 4.4 4.4 4.3 4.6
4.8 4.6 4.7 Y value, top surface (%) 71.3 70.9 70.9 71.1 70.2 69.0
69.5 69.4 Opacity, top surface (%) 91.6 91.3 90.7 91.6 90.4 90.4
90.3 90.1 Light scattering coefficient, top surface (m.sup.2/kg)
47.4 45.9 44.9 46.6 42.6 40.7 41.4 40.9 Absorption coefficient, top
surface (m.sup.2/kg) 2.73 2.74 2.68 2.73 2.70 2.83 2.77 2.76
[0045]
5TABLE 3 Properties of offset printing papers Amount of surface Dry
surface strength Ink require- Water penetration speed (Emco),
Sample sizing agent (g/m.sup.2) (IGT), top surface (m/s) ment
(g/m.sup.2) Print tone level S value, top surface (%) r/s Ref. 1
10.2 1.27 1.1 1.81 9.6 Ref. 2 -- 0.83 1.4 1.42 167.0 OP1 2.51 2.93
1.4 1.40 24.0 OP2 1.70 1.78 1.4 1.37 77.0 OP3 1.81 4.57 1.3 1.55
11.6 OP4 1.35 2.36 1.4 1.40 50.0 OP5 1.83 3.34 1.2 1.57 15.9 OP6
0.90 3.32 1.2 1.39 50.0 OP7 1.96 3.64 1.2 1.53 9.0 OP8 2.31 3.49
1.2 1.51 21.0 OP9 1.26 3.36 1.1 1.62 11.4 OP10 1.17 3.18 1.4 1.43
36.0 OP11 2.39 3.69 1.0 1.73 9.9 OP12 2.25 3.24 1.2 1.53 19.5 OP13
1.82 4.03 1.3 1.46 11.7 OP14 1.49 2.48 1.5 1.37 43.0 OP15 2.73 5.05
1.0 1.74 6.9 OP16 1.63 3.11 1.3 1.51 45.0
[0046]
6TABLE 4 Properties of gravure paper. Property Ref. 3. R1 R2 R3 R4
R5 R6 Dry matter content (%) 9.0 14.4 11.4 17.9 15.4 Viscosity
(mPas) 174 980 1560 506 Grammage (g/m.sup.2) 52.2 51.9 52.9 52.6
52.8 53.4 53.1 Amount of surface sizing agent 0.70 0.33 0.57 1.16
0.84 (g/m.sup.2) Thickness (.mu.m) 44 43 44 44 44 44 44 Density
(kg/m.sup.3) 1187 1206 1203 1195 1200 1214 1206 Bulk (m.sup.3/kg)
0.842 0.829 0.831 0.837 0.833 0.824 0.829 Roughness (PPS-10)
(.mu.m) 1.14 1.07 1.12 0.93 1.02 1.09 1.21 Roughness (PPS-20)
(.mu.m) 0.86 0.84 0.86 0.69 0.75 0.80 0.92 PPS 10/PPS 20 1.33 1.27
1.30 1.35 1.36 1.36 1.32 Gloss (Hunter) (%) 46.0 42.7 48.9 48.0
44.8 50.3 35.8 Roughness (Bendtsen) (ml/min) 24 25 4 11 4 2 2
Stiffness (Kodak) (mNm) 0.048 0.043 0.062 0.043 0.049 0.058 0.053
Water penetration speed 159 139 16 34 17 21 12 (Emco), S value (%)
Printing ink absorption (%) 14.6 15.8 2.5 3.5 2.0 2.7 2.8
[0047]
7TABLE 5 Properties of gravure paper. Property Ref. 3. R1 R2 R3 R4
R5 R6 Tensile index, machine direction (Nm/g) 42, 3 43, 0 45, 1 42,
0 44, 8 44, 1 45, 4 Elongation, machine direction (%) 1.04 1.21
1.25 1.18 1.26 1.25 1.25 Tensile energy absorption index, machine
272 322 350 306 351 343 352 direction (J/kg) Tensile stiffness
index, machine direction 6.17 5.56 5.69 5.47 5.62 5.70 5.63
(MNm/kg) Tear index, machine direction (mNm.sup.2/g) 3.18 3.16 3.15
3.37 3.22 3.03 3.35 Brightness ts (%) 67.6 67.7 66.3 67.3 67.1 66.5
67.2 Y-value ts (%) 72.1 72.3 71.1 71.9 71.8 71.2 72.0 Opacity ts
(%) 91.2 91.1 91.0 91.1 91.0 90.9 91.2 Light scattering coefficient
ts (m.sup.2/kg) 51.3 51.8 48.6 50.3 49.7 48.1 50.5 Light absorption
coefficient ts (m.sup.2/kg) 2.76 2.76 2.85 2.77 2.76 2.81 2.75
Dominant wavelength (nm) 573.1 572.8 573.0 573.1 573.1 573.3 573.0
Excitation purity ts (%) 4.41 4.38 4.80 4.46 4.59 4.68 4.69 Dry
surface strength (IGT) (m/s) 57 71 258 215 242 229 224
[0048]
8TABLE 6 Properties of gravure paper. Property Ref. 3. Ref. 4. Ref.
5. R1 R2 R3 R4 R5 R6 Printing ink tone level 1.86 2.03 1.86 1.82
2.02 2.03 2.00 2.02 2.02 Print through tone level 0.066 0.063 0.067
0.070 0.053 0.064 0.056 0.060 0.062 Print transparency (%) 3.6 3.1
3.6 3.9 2.6 3.2 2.8 2.9 3.0 Printed gloss (%) 66.4 82.4 70.5 62.8
74.8 74.7 73.8 73.8 72.2 Number of missing dots 24 1207 24 16 130
not 12 151 18 (dots/cm.sup.2) known Entropy 1.83 1.27 0.90 1.79
1.77 1.85 1.78 1.64 1.69
* * * * *