U.S. patent application number 11/091055 was filed with the patent office on 2005-08-04 for surface finishing of paper or board, and agent for this purpose.
This patent application is currently assigned to Clariant Finance (BVI) Limited. Invention is credited to Kohler, Achim, Martin, Gerd, Weigl, Christian, Weigl, Josef.
Application Number | 20050167064 11/091055 |
Document ID | / |
Family ID | 8243012 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050167064 |
Kind Code |
A1 |
Kohler, Achim ; et
al. |
August 4, 2005 |
Surface finishing of paper or board, and agent for this purpose
Abstract
Surface finishing of paper or board by applying an aqueous
solution (L.sub.w) of a surface-finishing active ingredient (W) to
a hydrophilic paper or board sheet (B), in which (W) consists of
(W.sub.1) polyethylene glycol with an average molecular weight
{overscore (M)}.sub.w of>1500 and optionally at least one
further additive which is a further finishing additive and/or a
formulation additive, and the paper or board sheet surface-treated
with (L.sub.w) is fed through smoothing rolls and dried, the
surface-finished paper and surface-finished board (B.sub.w)
produced, surface finishing agent for this purpose, and the use of
the surface-finished paper or board as substrate for graphic
processing.
Inventors: |
Kohler, Achim; (Heilbronn,
DE) ; Martin, Gerd; (Ettingen, CH) ; Weigl,
Christian; (Munchen, DE) ; Weigl, Josef;
(Munchen, DE) |
Correspondence
Address: |
CLARIANT CORPORATION
INTELLECTUAL PROPERTY DEPARTMENT
4000 MONROE ROAD
CHARLOTTE
NC
28205
US
|
Assignee: |
Clariant Finance (BVI)
Limited
|
Family ID: |
8243012 |
Appl. No.: |
11/091055 |
Filed: |
March 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11091055 |
Mar 28, 2005 |
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10070622 |
Mar 4, 2002 |
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6872282 |
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10070622 |
Mar 4, 2002 |
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PCT/IB00/01269 |
Sep 8, 2000 |
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Current U.S.
Class: |
162/135 ;
162/158; 162/160; 162/162; 162/164.3; 162/204 |
Current CPC
Class: |
D21H 21/30 20130101;
D21H 19/28 20130101 |
Class at
Publication: |
162/135 ;
162/158; 162/162; 162/164.3; 162/160; 162/204 |
International
Class: |
D21H 019/28; D21H
021/00; D21H 021/30; D21H 021/36 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 1999 |
EP |
99810808.8 |
Claims
1.-11. (canceled)
12. A process for the production of surface-finished paper or board
(B.sub.w), said process comprising the steps of applying to a
surface of a hydrophilic paper or board sheet (B) an aqueous
solution (L.sub.w) consisting of water and a surface-finishing
active ingredient (W) and optionally a non-finishing formulation
additive (F), in which the surface-finishing active ingredient (W)
consists of (W.sub.1) polyethylene glycol with an average molecular
weight {overscore (M)}.sub.w of >1500, or of (W.sub.1) and at
least one further additive selected from the group consisting of
(W.sub.2) at least one dye and/or optical brightener, (w.sub.3) a
wet strength additive selected from the group consisting of
products of the reaction of aldehydes with nitrogen compounds
containing amidic NH.sub.2 groups, if desired in combination with
suitable catalysts (W.sub.3"), and products of the reaction of
epichlorohydrin with aliphatic mono- or oligoamines, which are
optionally quaternized, (W.sub.4) at least one agent for pH
adjustment and mixtures thereof, and the non-finishing formulation
additive (F) is selected from the group consisting of (F.sub.11)
antifoams, (F.sub.12) agents for protecting against the damaging
effect of micro-organisms and mixtures thereof, and smoothing and
drying said surface-treated paper or board sheet through smoothing
rolls:
13. A process according to claim 12, wherein (W) consists of
polyethylene glycol (W.sub.1) or of polyethylene glycol (W.sub.1)
and wet strength additive (W.sub.3).
14. A process according to claim 12, wherein (W) consists of
polyethylene glycol (W.sub.1), at least one of additives (W.sub.2)
and (W.sub.3), and optionally additive (W.sub.4).
15. A process according to claim 12, wherein (W) comprises at least
one dye and/or optical brightener (W.sub.2) and the average
molecular weight {overscore (M)}.sub.w of polyethylene glycol
(W.sub.1) is in the range of 1600 to 4000.
16. A process according to claim 12, wherein (L.sub.w) consists of
water, polyethylene glycol (W.sub.1) and at least one of additives
(W.sub.3) and (F).
17. A process according to claim 12, wherein (W) comprises a wet
strength additive (W.sub.3).
18. A process according to claim 17, wherein the average molecular
weight {overscore (M)}.sub.w of polyethylene glycol (W.sub.1) is in
the range of 2000 to 20,000.
19. A process according to claim 12, wherein (W) consists of
polyethylene glycol (W.sub.1) and wet strength additive
(W.sub.3).
20. A process according to claim 12, wherein (W.sub.3) is
(W.sub.3') a crosslinkable product which is reactive with aliphatic
hydroxyl groups
21. A process according to claim 20, wherein (W.sub.3') is selected
from the group consisting of products of the reaction of aldehydes
with nitrogen compounds containing amidic NH.sub.2 groups, if
desired in combination with suitable catalysts (W.sub.3"), and
products of the reaction of epichlorohydrin with aliphatic mono- or
oligoamines, which are optionally quaternized.
22. A process according to claim 21, wherein (W.sub.3') is selected
from the group consisting of products of the reaction of
formaldehyde or glyoxal with urea or melamines, and products of the
reaction of epichlorohydrin with aliphatic mono- or oligoamines
with 2 to 6 carbon atoms, which are optionally quaternized.
23. A process according to claim 12, wherein (W) consists of at
least 30% by weight of polyethylene glycol (W.sub.1)
24. A process according to claim 12, wherein said aqueous solution
(L.sub.w) contains at least one non-finishing formulation additive
(F).
25. A process according to claim 12, wherein said aqueous solution
(L.sub.w) essentially consists of (W) and water.
26. Process according to claim 12, wherein said applying step
comprises spraying said aqueous solution (L.sub.w) on a surface of
said hydrophilic paper or board sheet (B).
27. A process according to claim 12, wherein said smoothing through
smoothing rolls comprises smoothing through smoothing rolls at a
smoothing pressure in the range of 8 to 500 KN/m
28. Process according to claim 12, wherein said smoothing rolls are
calendering rolls.
29. A process for the production of surface finished paper or board
(B.sub.w), said process comprising the steps of: a) forming a paper
web (B) from an aqueous pulp suspension and transporting the paper
web to a press section to remove a portion of the water from the
paper web to provide a hydrophilic paper or board sheet having a
moisture content .ltoreq.30% by weight b) applying to a surface of
the hydrophilic paper or board sheet (B) an aqueous solution
(L.sub.w) consisting of water and a surface-finishing active
ingredient (W) and optionally a non-finishing formulation additive
(F), in which the surface-finishing active ingredient (W) consists
of (W.sub.1) polyethylene glycol with an average molecular weight
{overscore (M)}w of >1500, or of (W.sub.1) and at least one
further additive selected from the group consisting of (W.sub.2) at
least one dye and/or optical brightener, (W.sub.3) a wet strength
additive selected from the group consisting of products of the
reaction of aldehydes with nitrogen compounds containing amidic
NH.sub.2 groups, if desired in combination with suitable catalysts
(W.sub.3"), and products of the reaction of epichlorohydrin with
aliphatic mono- or oligoamines, which are optionally quaternized.
(W.sub.4) at least one agent for pH adjustment and mixtures
thereof, and the non-finishing formulation additive (F) is selected
from the group consisting of (F.sub.11) antifoams, (F.sub.12)
agents for protecting against the damaging effect of
micro-organisms and mixtures thereof, c) passing the
surface-treated paper or board sheet to a smoothing roll zone and
therein subjecting the surface-treated paper or board to pressure
and drying to provide the surface-finished paper or board
sheet.
30. A process for the production of surface finished paper or board
(B.sub.w), said process comprising the steps of a) passing a
hydrophilic paper or board sheet to a re-wetting zone and therein
moistening the hydrophilic paper or board sheet to a moisture
content in the range of 4 to 16% by weight to provide a
re-moistened paper, b) applying uniformly to a surface of the
re-moistened sheet an aqueous solution (L.sub.w) consisting of
water and a surface-finishing active ingredient (W) and optionally
a non-finishing formulation additive (F), in which the
surface-finishing active ingredient (W) consists of (W.sub.1)
polyethylene glycol with an average molecular weight {overscore
(M)}w of >1500, or of (W.sub.1) and at least one further
additive selected from the group consisting of (W.sub.2) at least
one dye and/or optical brightener, (W.sub.3) a wet strength
additive selected from the group consisting of products of the
reaction of aldehydes with nitrogen compounds containing amidic
NH.sub.2 groups, if desired in combination with suitable catalysts
(W.sub.3"), and products of the reaction of epichlorohydrin with
aliphatic mono- or oligoamines, which are optionally quaternized.
(W.sub.4) at least one agent for pH adjustment and mixtures
thereof, and the non-finishing formulation additive (F) is selected
from the group consisting of (F.sub.11) antifoams, (F.sub.12)
agents for protecting against the damaging effect of
micro-organisms and mixtures thereof, c) passing the
surface-treated paper or board sheet to a calendering zone and
therein subjecting the surface-treated paper or board to calender
pressure and drying to provide the surface-finished paper or board
sheet.
31. A process for the production of surface finished paper or board
(B.sub.w), said process comprising the steps of: a) passing a
hydrophilic paper or board sheet to a re-wetting zone and therein
moistening the hydrophilic paper or board sheet with an aqueous
solution (L.sub.w) consisting of water and a surface-finishing
active ingredient (W) and optionally a non-finishing formulation
additive (F), in which the surface-finishing active ingredient (W)
consists of (W.sub.1) polyethylene glycol with an average molecular
weight {overscore (M)}w of >1500, or of (W.sub.1) and at least
one further additive selected from the group consisting of
(W.sub.2) at least one dye and/or optical brightener, (W.sub.3) a
wet strength additive selected from the group consisting of
products of the reaction of aldehydes with nitrogen compounds
containing amidic NH.sub.2 groups, if desired in combination with
suitable catalysts (W.sub.3"), and products of the reaction of
epichlorohydrin with aliphatic mono- or oligoamines, which are
optionally quaternized. (W.sub.4) at least one agent for pH
adjustment and mixtures thereof, and the non-finishing formulation
additive (F) is selected from the group consisting of (F.sub.11)
antifoams, (F.sub.12) agents for protecting against the damaging
effect of micro-organisms and mixtures thereof, to a moisture
content in the range of 4 to 16% by weight to provide a
re-moistened paper, b) passing the surface-treated paper or board
sheet to a calendering zone and therein subjecting the
surface-treated paper or board to calender pressure and drying to
provide the surface-finished paper or board sheet.
32. A process according to claim 31, wherein the re-moisturising
solution comprises 0.01 to 10% by weight of (W).
33. Paper or board (B.sub.w) surface-finished in accordance with
the process of claim 12.
34. Paper or board (B.sub.w) according to claim 22 which is
essentially size-free and is intaglio printing and offset printing
paper or board.
35. Process for the production of graphically processed paper or
board by application of at least one graphic ink pattern to a
substrate of paper or board, and drying, wherein the substrate used
for this purpose is surface-finished paper (B.sub.w) or
surface-finished board (B.sub.w) according to claim 22.
Description
[0001] In papermaking and board production today, particularly with
high-speed papermaking machines, the achievement of increasing
quality demands, such as
[0002] 1. High gloss and high smoothness, with avoidance of losses
of strength and so-called "calender blackening"
[0003] 2. High surface strength, which do not result in interfering
dusting and flaking during production and processing (particularly
deposits on calender rolls during calendering or on rubber blankets
during printing),
[0004] 3. Improvement in the processing properties of the paper in
order, for example, to prevent the "fold breaking" which often
occurs
[0005] 4. The tendency towards high brightness of papers and boards
which has been ongoing for years
[0006] 5. The demand for good ageing resistance of-the papers and
boards produced, particularly to the action of light and heat (in
the brightness and also in the mechanical properties)
[0007] 6. Suitability of the papers and boards produced for graphic
processing, principally for printing, particularly as printing
papers and boards,
[0008] increasingly represents a challenge to papermakers.
[0009] In order to achieve high gloss and smoothness values, high
line pressures are often necessary during calendering, which can
result in losses of strength of the paper and in so-called
"calender blackening". This problem exists in particular in
intaglio printing papers, for example in LWC/ULWC papers [LWC=Light
Weight Coated; ULWC=Ultra Light Weight Coated].
[0010] In heavily coated or surface-sized papers or boards, the
fibre structure is stuck together to form a cover. In U.S. Pat. No.
2,723,306, a polyethylene glycol coating is used to protect the
still un-dried pigment coating (for example as "antichalking");
EP-A-192600 describes aqueous preparations which comprise an
optical brightener of a defined formula from the
bistriazinylaminostilbenedisulphionic acid series and a
polyethylene glycol 1000 to 3000 and which serve as admixture to
latex-containing paper coating compositions; U.S. Pat. No.
4,303,717 describes multilayer paper laminates for heat-peelable
decals, in which polyethylene glycols are applied as release film
to the release layer for better removal of the decal layer. It is
possible per se to combine a polyethylene glycol in the paper
composition; in this case, the majority of the polyethylene glycol
remains in the waste water.
[0011] It is also known, e.g. from U.S. Pat. Nos. 5,935,384 and
3,779,791, to use certain polyethylene glycols for impregnating
produced paper but these impregnated papers are not subjected to
any smoothing pressure treatment. Thus in U.S. Pat. No. 5,935,384
there is described the production of disintegrable body paper, in
which a body paper is impregnated with an aqueous composition
comprising a humectant (in the examples the humectant is glycerol,
in the description there are also mentioned some glycols, such as
propylene glycol, polyethylene glycol 200-1000 and some other low
molecular compounds) and in some cases also polyethylene glycols
1000-20000, and other additives, and the impregnated paper is
air-dried. In U.S. Pat. No. 3,779,791 there is described the
production of sterilized paper by impregnation of calendered paper
with a concentrated polyethylene glycol solution and heat-treatment
at 180-200.degree. C. for a prolonged time (ca. 40 min.). Also
here, as in U.S. Pat. No. 5,935,384, there is no mention of any
smoothing roll treatment of the impregnated paper. In EP 624687 A1
there are described composition of a certain optical brightener
[4,4'-bis(2-sulphostyryl)-dip- henyl] for the production of white
pigment coating pastes for the coating of paper, or for using in
the size, wherein the optical brightener composition, when in the
form of ail aqueous solution, according to some examples contains
as a solvent, a combination of a glycol (propylene glycol, ethylene
glycol) and a rather low molecular polyethylene glycol (in the
respective examples polyethylene glycol 300, 600 or 1500); the
solution is used in the size or combined with the other components
of a coating mass and the resulting size or coating mass is applied
on the paper by conventional means. Also here, as there is no
mention of any smoothing roll treatment of the sized or coated
paper. These processes relate to particular disintegration,
sterilization or respectively optical brightener solution and
application methods, and do not relate to any teaching concerned
with the solution of the previously mentioned problems or with
meeting the above or below mentioned requirements in papermaking
and board production.
[0012] Given the constant tendency towards improving processes and
increasing production efficiency and given increased environmental
and waste-water consciousness, it is desired not only to improve
the paper quality, but also at the same time to avoid reductions in
production efficiency and additional pollution of waste water
(caused particularly, for example, by strong sizing or coating) in
papermaking and paper recycling. It is particularly desired to
retain the inherent character of the cellulose fibres (for example
flexibility, elasticity and strength) of the support web to the
greatest possible extent; it is furthermore also desired to counter
yellowing caused by the action of light and/or heat to the greatest
possible extent and to provide suitability for writing and for
printing--in particular compressibility, smoothness, gloss,
brightness and strength--as well as possible.
[0013] Surprisingly, it has now been found that a surprisingly good
paper quality or board quality which meets the above requirements
can be achieved with optimum utilization of the performance of the
paper-making machine by application of certain solutions (W) of
high-molecular-weight polyethylene glycols (W.sub.1) and smoothing,
as defined below, to a hydrophilic paper or board surface, as
defined and described below, without or with a minimum of sizing
agent.
[0014] The invention relates to the process for the production of
surface-finished paper and/or board, to the surface-finished paper
produced or surface-finished board produced, to the surface
finishing agent for this purpose, and to the use of the
surface-finished papers or boards as substrate for writing,
printing or other graphic uses.
[0015] A first subject-matter of the invention is thus a process
for the production of surface-finished paper or board (B.sub.w)
which is characterized in that an aqueous solution (L.sub.w) of a
surface-finishing active ingredient (W) is applied to a hydrophilic
paper or board sheet (B), in which (W) consists of
[0016] (W.sub.1) polyethylene glycol with an average molecular
weight {overscore (M)}.sub.w of>1500 and optionally at least one
further additive which is a further finishing additive and/or a
formulation additive,
[0017] and the paper or board sheet surface-treated with (L.sub.w)
is fed through smoothing rolls and dried.
[0018] A suitable paper or board sheet (B) is a support sheet made
from any desired primary and/or secondary substances which are
suitable for the production of paper or board, in particular made
from conventional fibre material, principally cellulosic fibre
material, for example from hardwood (for example maple, birch,
beecil, poplar), from softwood (for example pine, spruce, larch,
fir), from annual plants (for example straw, jute, ramie, bagasse,
flax, hemp, reed, sisal, coconut, cotton) or from textile fibres
(for example rags, cotton, linen, flax, ramie, jute) or also from
recycled paper production waste or from used paper, where the
non-digested fibres, namely textile fibres, wood fibres and fibres
from annual plants, can be processed in a manner which is
conventional per se to give pulp, for example by mechanical and/or
chemical and/or thermal methods (in particular wood pulp,
mechanical wood pulp, brown wood pulp, yellow straw pulp, chemical
pulp, semichemical pulp and chemically digested pulp), and recycled
printed paper or used paper, can, if necessary, be deinked. If
desired or if necessary, the material can be bleached with
conventional bleaching agents, for example reductively and/or
oxidatively (for example with sodium hydrosulphite, thiourea
dioxide or hydrogen peroxide). Particularly worthy of mention are
the lignin-containing substrates (particularly those which contain
at least 5%, preferably at least 10%, of lignin, based on dry
fibres), principally paper containing wood pulp or semichemical
pulp or board containing wood pulp or semichemical pulp. The pulp
or the corresponding fibres can, if desired after blending various
types of fibre and/or types of pulp with one another, for example
from mechanically digested pulp and/or chemically (sulphite or
sulphate method) and/or thermally digested pulp and/or
combination-digested pulp (semichemical pulp), be processed
further, optionally with at least 10% of recycled paper or used
paper. It is possible to use any desired conventional additives
which are suitable for papermaking, such as, for example dewatering
and/or retention agents, and if desired optical brighteners, dyes,
sizing agents and/or fillers (for example kaolin, talc or other
silicates or calcium carbonate), as can usually be admixed with the
aqueous pulp composition before sheet formation.
[0019] The aqueous pulp suspension intended and formulated for the
production of the web (B) can be applied in any conventional manner
to the wire end, where the dewatering to the desired water content
takes place. From the wire end, the web is then transported to the
press section, where the water content is reduced further, for
example usually in the range from 70 to 30%, so that the moist
sheet reaches the dry end with a water content of .ltoreq.30%.
After the dry end, the support sheet produced is fed through the
calender (intermediate or dry calender) or otherwise through drying
rolls, and can if desired by given a light surface sizing or
coating, particularly--if calendering is being carried out--to the
extent that it is still hydrophilic. The paper sheet can then be
dried again and then rolled up. If calendered paper is being
produced, calendering is carried out, after the paper has been
rolled up, on the calender, for which purpose it is re-moistenened
in advance. However, the calendering can also be carried out, in
suitable papermaking machines, immediately thereafter (i.e. without
interruption by rolling-up) in a single operation during
papermaking. If multilayered board is being produced, the
respective lower. middle and upper layers are couched to one
another in the press section before drying.
[0020] The paper or board sheet (B) to be employed in accordance
with the invention is hydrophilic, in particular it has in dried
form a hydrophilicity which corresponds to a water absorption
capacity of .gtoreq.10.degree. Cobb, advantageously
.gtoreq.15.degree. Cobb, for example in which the water absorption
capacity is in the range from 15 to 80.degree. Cobb, in particular
in the range from 20 to 60.degree. Cobb [measured on the dry sheet
(B)].
[0021] The paper or board sheet may, if desired, be pulp-sized
and/or surface-sized, in particular to such a degree that it still
has the above-mentioned hydrophilicity after drying. Any desired
conventional sizing agents can be used for this purpose, for
example natural products, such as starch (for example enzymatically
degraded starch or other starch derivatives, for example swelling
starch), carob seed flour, resin size (for example with aluminium
sulphate) or carboxymethylcellulose, or fully or semi-synthetic
products, such as alkylketene dimers, fatty acid anhydrides or
soaps, fluorinated fatty derivatives (for example those of the
"Scotchben" type) or chromium fatty acid derivatives (for example
chromium stearate and/or chromium myristate, for example of the
"Quilon" type), and, if desired, also products of greater
hydrophobicity, such as terpene resins, petroleum cracking
polymers, naphthenic derivatives, or also cationic acrylic ester
copolymers, vinyl polymers, hydrophobic derivatives of
polyfunctional amines and copolymers of maleic acid and vinyl
monomers. Surface sizing can be carried out, for example, at an
application rate which corresponds to a coating of .ltoreq.10
g/m.sup.2, preferably .ltoreq.8 g/m.sup.2, for example in the range
from 0.05 to 10 g/m.sup.2, particularly 8 g/m.sup.2, based on the
solids content and dry substrate.
[0022] After the treatment with (L.sub.w) and before calendering,
the paper or board sheet may, if desired, be coated, in particular
light weight coated or ultra light weight coated (so long as it
still has the above-mentioned hydrophilicity), and, if it is
coated, it is then also calendered, with moistening (usually, for
example, with steam) being carried out before the calendering.
Conventional coating compositions can be employed for this purpose,
in particular containing pigment, principally containing white
pigment (for example kaolin, talc, diatomaceous earth,
montmorillonite, attapulgite, bentonite, satin white, calcium
carbonate, titanium dioxide, anhydrite, titanium dioxide/anhydrite,
potassium titanate, zinc oxide or sulphate, calcium or barium
sulphate, aluminium sesquioxide trihydrate, sodium
silico-aluminate, etc.), and/or containing optical brighteners, or
also those containing neither white pigment nor optical
brighteners. For a possible coating, any desired binders which are
conventional per se are suitable, for example on a vegetable or
animal basis, such as, for example, casein, modified starch,
cellulose size and animal size, and synthetic binders, such as
polymer dispersions, styrene-butadiene latex, styrene-acrylic
latex, or preparations and mixtures, such as starch in combination
with calcium stearate, it being possible for white pigments to be
combined, for example, with binders, such as, for example, those
mentioned above, particularly styrene-butadiene latex,
styrene-acrylic latex or oxidized starch, and/or with auxiliaries,
such as tetrasodium pyrophosphate. In order to increase the wet
tear strength of the product, the coating compositions may
optionally additionally contain crosslinkable resins, such as, for
example, melamine resin precursors, principally methylolmelamines,
and urea resin precursors, principally optionally cyclic ureas,
such as dihiydroxyethyleneurea and dimethylolurea, advantageously
in combination with suitable crosslinking catalysts. The coating
composition can be coated, for example, at an application rate
which corresponds to application of .ltoreq.10 g/m.sup.2,
preferably <8 g/m.sup.2, for example in the range from 0.5 to 10
g/m.sup.2, principally from 0.8 to 8 g/m.sup.2, based on the solids
content and dry (oven-dry="odry") substrate. This is advantageously
followed by drying and, for the treatment with (L.sub.w),
subsequent moistening.
[0023] Preferably no coating is carried out before calendering.
[0024] The average molecular weight {overscore (M)}.sub.w of
(W.sub.1) is advantageously in the range from 1600 to 20,000,
preferably from 1800 to 8000.
[0025] As polyethylene glycols (W.sub.1), it is possible to use
commercially available products, principally those with a narrow
molecular weight distribution (for example in which >99%,
preferably >99.6%,.of the entire respective polyethylene glycol
is in the molecular weight range from 0.25.multidot.{overscore
(M)}.sub.w to 4.multidot.{overscore (M)}.sub.w, preferably from
0.4.multidot.{overscore (M)}.sub.w to 2.multidot.{overscore
(M)}.sub.w), in particular those which are essentially free from
low-molecular-weight polyethylene glycols which are liquid or
semiliquid at room temperature. The polyethylene glycols (W.sub.1)
advantageously contain less than 5% by weight, preferably less than
1% by weight, of polyethylene glycol with a molecular weight of
.ltoreq.1000 and less than 1% by weight, preferably less than 0.2%
by weight, of polyethylene glycol with a molecular weight of
.ltoreq.800.
[0026] As further finishing additives in (W) which may be present
in dissolved form in (L.sub.w), the following, in particular, come
into consideration:
[0027] (W.sub.2) at least one dye and/or optical brightener,
[0028] and/or (W.sub.3) at least one wet strength additive.
[0029] Particularly suitable as (W.sub.2) are
[0030] (W.sub.21) water-soluble dyes
[0031] and (W.sub.22) water-soluble optical brighteners.
[0032] As (W.sub.1), it is possible to use any desired
water-soluble dyes and dye mixtures, as generally suitable and
known for dyeing paper, for example anionic or cationic dyes. Such
dyes are generally known in industry and are described in large
number in the specialist literature. Reference is made, in
particular, to the dyes defined and described in the "Colour Index"
under the names "Acid Dyes", "Direct Dyes" and "Basic Dyes", in
particular to those which are expressly recommended for the dyeing
of paper, particularly direct dyes. As (W.sub.22), it is possible
to use any desired, preferably anionic optical brighteners which
are water-soluble in the form of their alkali metal salts, in
particular those which are known to be suitable for the optical
brightening of paper, preferably those which contain from 2 to 8
anionic groups, preferably sulpho groups and/or carboxyl groups,
for example from 2 to 6 sulpho groups and optionally from 2 to 4
carboxylate-groups. Anionic optical brighteners, in particular
those which are suitable for the optical brightening of paper, are
known in industry and are also described in large number in the
specialist literature. Mention may be made, for example, of
brightener categories from the diaminostilbene, bisstilbyl and
1,3-diphenylpyrazoline series, for example of the following
formulae: 1
[0033] in which
[0034] R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each, independently of
one another, denote the radical of an amine or alcohol,
[0035] R.sub.5 and R.sub.7 each, independently of one another,
denote C, .sub.2-alkyl, phenyl or sulphophenyl,
[0036] R.sub.6 and R.sub.8 each, independently of one another,
denote hydrogen, C.sub.1-2-alkyl, phenyl or sulphophenyl,
[0037] R.sub.9 and R.sub.10 each, independently of one another,
denote hydrogen, C.sub.1-2-alkyl or -alkoxy, chlorine or
--SO.sub.3M,
[0038] R.sub.11 denotes a radical of the formula
--SO.sub.2--(NH).sub.m--(- C.sub.2-4alkylene)-SO.sub.3M,
[0039] m denotes zero or!,
[0040] R.sub.12 denotes hydrogen,
[0041] or R.sub.11 and R.sub.12 together denote a furan-2-one ring
condensed in 3-4,
[0042] R.sub.3 denotes hydrogen or --CH.sub.2--SO.sub.3M,
[0043] R.sub.14 denotes hydrogen or chlorine,
[0044] R.sub.15 denotes hydrogen, or if R.sub.14 stands for
chlorine, also methyl
[0045] and M denotes hydrogen or an alkali metal cation,
[0046] where the formula (IV) contains at least one sulpho group in
at least one of R.sub.11 and R.sub.12.
[0047] If R.sub.1, R.sub.2, R.sub.3 and/or R.sub.4 stand for the
radical of an alcohol, they preferably denote C.sub.1-4-alkoxy or
phenoxy.
[0048] R.sub.1 and R.sub.3 preferably stand for anilino or mono- or
disulphoanilino.
[0049] R.sub.2 and R.sub.4 preferably stand for the radical of a
low-molecular-weight aliphatic amine which is optionally
substituted by hydroxyl, CN, CONH.sub.2 or/and COOM, or
alternatively of morpholine.
[0050] The dyes and optical brighteners (W.sub.2) can be employed
in pure (for example purified by membrane filtration) or also
diluted form, in particular in the commercially available forms.
Since tile solutions (L.sub.w) to be employed in accordance with
the invention are substantially electrolyte-insensitive, in
particular insensitive to electrolytes as used as diluents in dyes
(for example sodium chloride, potassium chloride, sodium sulphate
or sodium carbonate, etc.), and are also compatible with
electrolyte-free diluents (for example urea, dextrin, etc.), they
are also correspondingly compatible with any dilution in
(W.sub.2).
[0051] Of the dyes and optical brighteners (W.sub.2), the more
water-soluble ones are preferred, in particular those with a water
solubility of at least 50 g/l at 20.degree. C. and pH 7. In the
case of the anionic ones, particular preference is given to those
which contain on average at least one sulpho group per benzene ring
in the molecule (where fused benzene rings count individually,
i.e., for example, naphthalene rings count as two benzene
rings).
[0052] If dyes and/or optical brighteners (W.sub.2) are employed in
(L.sub.w), it is of advantage to employ low-molecular-weight
polyethylene glycols (W.sub.1), in particular those with an average
molecular weight in the range from 1600 to 4000, preferably from 1
800 to 2500.
[0053] Suitable wet strength additives (W.sub.3) are, in
particular, (W.sub.3') crosslinkable products which are reactive
with aliphatic hydroxyl groups [whether those from (W.sub.1), or
those from the substrate], for example products of the reaction of
aldehydes, for example formaldehyde or biformyl (glyoxal) with
nitrogen compounds containing amidic NH.sub.2 groups, principally
with urea or melamines, for example methyolmelamines, methylolureas
and glyoxal derivatives of urea (for example dihydroxyethyleneurea
and polyhydroxylated glyoxal-urea resins), if desired in
combination with suitable catalysts. (W.sub.3"), which are, for
example acids or Lewis acids, such as magnesium chloride, zinc
chloride or sulphuric acid, or products of the reaction of
epichlorohydrin with aliphatic mono- or oligoamines, for example
with 2 to 6 carbon atoms (for example dimethylamine,
ethylenediamine, propylenediamine, diethylene-triamine,
ethylene-propylenetriamine or triethylenetetramine), which are
optionally quaternized.
[0054] If wet strength additives (W.sub.3) are employed in
(L.sub.w), it is of advantage to employ relatively
high-molecular-weight polyethylene glycols (W.sub.1), in particular
those with an average molecular weight in the range from 2000 to
20,000, preferably from 3000 to 8000.
[0055] The content of (W.sub.1) in (L.sub.w) is generally as
desired and can extend up to the solubility limit of the
polyethylene glycol (W.sub.1), for example up to 50% by weight. The
content of (W.sub.1) in (L.sub.w) is preferably in the range from
0.1 to 20% by weight, preferably from 0.5 to 15% by weight.
[0056] If (W.sub.2) is employed, the content of (W.sub.2) in
(L.sub.w) is generally as desired and can extend up to the
solubility limit of the respective dye or optical brightener
(W.sub.2); the content of (W.sub.2) in (L.sub.w) is advantageously
in the range from 0.1 to 68% by weight of pure dye or pure
brightener, preferably from 0.2 to 30% by weight of pure dye or
pure brightener, particularly preferably from 0.5 to 15% by weight
of pure dye or pure brightener, where, in accordance with a
preferred cmbodinticil of tihe invention, the proportion of pure
dye or pure brightener is advantageously in the range from 1 to
200% of (W.sub.1), preferably from 20 to 150% of (W.sub.1).
[0057] If (W.sub.3) is employed, the content of (W.sub.3) in
(L.sub.w) is generally as desired and can extend up to the
solubility limit of the crosslinking precursor (W.sub.3'); the
content of (W.sub.3) in (L.sub.w) is advantageously in the range
from 0.1 to 30% by weight of crosslinking precursor (W.sub.3'),
preferably from 0.5 to 15% by weight of crosslinking precursor
(W.sub.3'). The weight ratio of the crosslinking precursor
(W.sub.3') to (W.sub.1) can per se be as desired; the weight ratio
(W.sub.3')/(W.sub.1) is advantageously not greater than 1/1,
preferably not greater than 0.7/1; the weight ratio
(W.sub.3')/(W.sub.1) is advantageously in the range from 0.1/100 to
50/100, preferably from 0.5/100 to 40/100.
[0058] The solutions (L.sub.w) can have any desired pH, as is
generally suitable for the surface treatment of paper or board,
advantageously in the weakly acidic to weakly alkaline pH range,
preferably in the pH range from 5.5 to 8, in particular from 6 to
7.5. For possible pH adjustment or correction, suitable additives
may also be present in (W), as needed, in particular
[0059] (W.sub.4) at least one agent for pH adjustment.
[0060] As (W.sub.4), use can be made, in particular, of acids,
bases and/or buffers, as can otherwise usually be employed per se
in the course of papermaking, in particular acids, for example
mineral acids, such as sulphuric acid, hydrochloric acid or
phosphoric acid, or low-molecular-weight aliphatic carboxylic
acids, for example with 1 to 6 carbon atoms, for example formic
acid, acetic acid, lactic acid, tartaric acid, oxalic acid or
citric acid, bases, for example alkali metal hydroxides, carbonates
or bicarbonates, lime milk, magnesium oxide or hydroxide, ammonia
or low-molecular-weight aliphatic amines, for example mono-, di- or
triethanolamine or mono-, di- or triisopropanolamine, or buffers,
such as, for example, mono- or disodium and/or -potassium
phosphates, borax, monopotassium tartrate or sodium acetate.
[0061] The active ingredient (W) dissolved in (L.sub.w)
advantageously consists of (W.sub.1) and--if present--at least one
further of the additives (W.sub.2), (W.sub.3) and (W.sub.4). (W)
advantageously consists of at least 30% by weight of (W.sub.1) and
any remainder to 100% by weight of at least one of the additives
(W.sub.2), (W.sub.3) and (W.sub.4). Preferred active ingredients
(W) are, in particular, those in which (W) consists essentially
exclusively of (W.sub.1), or those in which (W) consists
essentially of (W.sub.1) and (W.sub.2) and optionally (W.sub.4),
where the average molecular weight {overscore (M)}.sub.w of
(W.sub.1) is in the range from 1600 to 4000, preferably from 1800
to 2500, or also those in which (W) essentially consists of
(W.sub.1) and (W.sub.3) and optionally (W.sub.4), where the average
molecular weight {overscore (M)}.sub.w of (W.sub.1) is in the range
from 2000 to 20,000, preferably from 3000 to 8000.
[0062] The concentration of (W) in (L.sub.w) may be as desired per
se and can if desired extend up to the solubility limit of the
entire active ingredient or active ingredient mixture (W), for
example up to 70% by weight, principally up to 40% by weight of
(W), it is particularly advantageously in the range from 0.1 to 40%
by weight, preferably from 0.2 to 30% by weight of (W) in
(L.sub.w).
[0063] The described aqueous solutions (L.sub.w) of the active
ingredients (W) may, if desired, contain further suitable
non-finishing formulation additives (F) for the purposes of better
storage and/or use properties, in particular
[0064] (F.sub.1) at least one agent for retaining the physical form
of the preparation and/or for avoiding adverse changes, for example
adverse foaming, during application.
[0065] Non-finishing formulation additives (F.sub.1) which come
into consideration are principally
[0066] (F.sub.11) antifoams
[0067] and (F.sub.12) agents for protecting against the damaging
effect of microorganisms.
[0068] Suitable as (F.sub.11) are any desired antifoams, for
example waxes, paraffins, vegetable or animal oils or mineral oils
in disperse form, silicone antifoams, silicic acid,
ethylenebisstearamide and/or mixtures of two or more thereof. In
particular, it is possible to use commercially available
preparations. The amounts of antifoam which can be used in the
preparations according to the invention are in the ranges which are
usual per se and are also dependent on the type and amount of the
other components (W.sub.1) and, if used, (W.sub.2) and/or
(W.sub.3). In general, very small amounts of antifoam, for example
.ltoreq.2% by weight, particularly from 0.01 to I % by weight,
based on the total aqueous preparation (L.sub.w), are
sufficient.
[0069] Suitable as (F.sub.12) are in general known substances,
essentially fungal or bacterial growth-inhibiting substances and/or
microbicides, as are commercially available, and the concentrations
used call vary depending on the application [whether for protection
of the solution (L.sub.w) or, if desired, also of the treated paper
or board] and correspond to those recommended in each case; they
are, for example .ltoreq.2% by weight, particularly from 0.01 to 1%
by weight, based on the total aqueous preparation (L.sub.w).
[0070] The aqueous solutions (L.sub.w) contain the components (W),
in particular (W.sub.1) and the optionally present further
additives (W.sub.2), (W.sub.3) and/or (W.sub.4) in dissolved form
The additives (F) can, with the exception of a few of the antifoams
(F.sub.1), also be in the form of a true or colloidal solution or,
in the case of water-insoluble antifoams, such as, for example,
waxes, paraffins or oils, also in the form of a dispersion [where,
if they are present at all, their proportion is so small that tile
aspect of (L.sub.w) is that of a clear solution]. A particular
subject-matter of the invention is represented by the solutions
(L.sub.w) which essentially consist of (W), water and, if desired,
(F).
[0071] The solutions (L.sub.w) can be prepared by simple mixing of
(W.sub.1) with water and, if desired, admixing of at least one of
the components (W.sub.2), (W.sub.3) and (W.sub.4) and, if desired,
addition of (F), and can be handled, transported and/or used
directly in the form in which they have been prepared. The
concentration of (W) can vary greatly depending on the type of
application of the surface finishing agent. If very dilute
solutions (L.sub.w) are used, it may also be of advantage first to
prepare a concentrated solution (L.sub.w), for example with a (W)
content in the range from 5 to 70% by weight, preferably from 10 to
40% by weight, for the purposes of transport and storage, and then
to dilute this to the desired use concentration with water, for
example to a (W) content in the range from 0.1 to 20% by weight,
preferably from 0.2 to 10% by weight.
[0072] The "smoothing rolls" in the process of the invention may be
any rolls or cylinders in the papermaking machine, in which the
paper or board sheet treated with (L.sub.w) is subjected to
pressure and smoothing, in particular in order to further compact
the fibrous structure of the sheet and provide the suface with a
corresponding gloss and/or smoothness. More particularly they
include calenders, smoothing presses and drying cylinders.
[0073] The solutions (L.sub.w) are advantageously applied to the
surface of the paper or board sheet (B) in at least one suitable
section of the papermaking machine in which the respective sheet
(B) is capable of taking up liquid, in particular where drying
takes place, principally, for example, in the press section or
preferably in the dry end before the smoothing press, and/or, for
calendered paper, also in the re-moistening before calendering. The
application of the solution (L.sub.w) advantageously takes place in
such a way that (W.sub.1) is increased in concentration at the
paper or board surface during drying by the respective rolls, in
particular calenders. In particular, the solution (L.sub.w) can,
for example, be sprayed onto the sheet (B) or applied by means of
rolls, either so that the sheet is not soaked with (L.sub.w) or
alternatively so that a paper sheet can also be soaked with
(L.sub.w), but is then dried in such a way that (W.sub.1) increases
in concentration at the surface of the sheet during drying.
(L.sub.w) is advantageously applied in such a concentration that
the entire moisture content of the paper or board is in the range
form 4 to 30% by weight, preferably from 5 to 25% by weight, in
particular is in the range from 8 to 30% by weight, preferably from
12 to 25% by weight, in the dry end or is in the range from 4-to
16% by weighty preferably from 5 to 14% by weight, in the
re-moistening before calendering.
[0074] The application of (L.sub.w) can be carried out on one or
both sides, depending on the type and purpose of the paper or
board. One-sided application is suitable, for example, for a
cardboard top layer, for label, poster or packing paper. Two-sided
application is suitable, for example, for graphic papers, book
printing, magazine, newspaper, letter, drawing or office paper, or
also for special single-layer types of cardboard, such as, for
example Bristol board. (L.sub.w) is advantageously applied at such
an application rate that the concentration of (W), based on the dry
substrate, is in the range from 0.005 to 8 g/m.sup.2. preferably
from 0.02 to 2 g/m.sup.2, and the concentration of (W.sub.1), based
on the dry (odry) substrate, is in the range from 0.005 to 5
g/m.sup.2, advantageously from 0.01 to 3 g/m.sup.2, preferably from
0.05 to 1 g/m.sup.2. The moist paper or board sheet which has been
surface-treated with (L.sub.w) can then be fed through the
respective rolls and dried, in particular smoothed by roll
pressing, preferably through rolls or calenders of the dry or
intermediate calender or smoothing press or through calenders for
calendering.
[0075] The application of the (W) solution (L.sub.w) is
advantageously carried out in at least one suitable section of
papermaking, advantageously in a section in which the support sheet
has a relatively low moisture content, for example .ltoreq.40%,
preferably .ltoreq.30%, so that the aqueous solution (L.sub.w) is
distributed as uniformly as possible on the surface of the support
sheet.
[0076] A suitable section of papermaking or board production is the
dry end. If an application of (L.sub.w) is carried out in the dry
end, it is advantageous to carry out neither surface sizing nor
coating in this section. (L.sub.w) is advantageously applied in the
dry end in or before the calenders to the support sheet which still
has an inherent residual moisture as is usual in these sections of
the papermaking machine, for example in the range from 4 to 30% by
weight, in particular from 8 to 30% by weight, principally from 12
to 25% by weight. In dry calenders, the solution (L.sub.w) can be
applied, for example, by spraying or roll application, for example
using analogous spray units or application rolls or other
application systems, as known, for example, for surface sizing. For
this type of application, preference is given to concentrated
solutions (L.sub.w), for example those having a (W) content in the
range from 5 to 70% by weight, preferably from 10 to 40% by weight,
in order to introduce as little additional water as possible, which
then has to be evaporated. If (L.sub.w) is applied in the
intermediate calenders, either a concentrated solution (L.sub.w),
as in the dry calenders, can be applied or, if re-moistening with
water, added to the moistening water in suitable concentration, or
a dilute solution (L.sub.w), for example with a (W) content of from
0.01 to 10% by weight, preferably from 0.02 to 5% by weight, can
also be used for moistening the support sheet in the wet calenders.
The drying can be carried out in a manner conventional per se,
using the usual drying rolls and drying roll batteries and, if
desired, calenders and calender batteries in the dry end, and under
the drying temperature conditions which are usual therein, for
example with dry steam or hot air or other heating systems, for
example in the temperature range from 100 to 250.degree. C., and
under the smoothing and roll pressure, in particular nip pressure
and line pressure conditions, which are usual per se therein.
[0077] A further suitable section of papermaking or board
production is calendering (calendering). If an application of
(L.sub.w) is carried out in the re-moistening before calendering,
the paper or board sheet can, if desired, also be lightly
surface-sized or coated so long as the above-mentioned
hydrophilicity of the dried sheet is maintained. (L.sub.w) is
advantageously applied in the calendering section in or before the
calenders to the support sheet which has a moisture content
corresponding to re-moistening, as is usual for calendering, for
example in the range from 4 to 16% by weight, principally from 5 to
14% by weight. Before calendering, the solution (L.sub.w) can, for
example, be applied to the re-moistenened sheet by spraying or with
application rolls, for example using analogous spray or other
application systems as are known, for example, for surface sizing.
For this type of application, preference is given to concentrated
solutions (L.sub.w), for example those having a (W) content in the
range from 5 to 70% by weight, preferably from 10 to 40% by weight.
However, (L.sub.w) can also be used with particular advantage in
the re-moistening water; in this case, for example, either a
concentrated solution (L.sub.w) in suitable concentration can be
added to the re-moistening water, or a dilute solution (L.sub.w),
for example with a (W) content of from 0.01 to 10% by weight,
preferably from 0.02 to 5% by weight, can also be used for the
re-moistening of the sheet. The calendering/drying can be carried
out in a manner conventional per se, using the calenders and
calender batteries usual in calendering, and under tile usual
conditions therein, for example with cooling of the calenders or
temperature regulation with steam or other temperature regulation
systems, for example in the temperature range from.40 to
120.degree. C., and under the smoothing and calender pressure, in
particular nip pressure and line pressure conditions which are
conventional per se therein.
[0078] The paper and board production rate can be maintained at the
levels which are conventional per se, for example at from 60 to
1700 m/min, the process according to the invention enabling a
surprisingly high utilization of the machine performance, since the
surface finishing with (W.sub.1) according to the invention
provides the surface of the paper or board sheet with a
surprisingly good, substantially flake-free structure while
simultaneously increasing the wet tear strength, so that production
can take place at very high speed--for example from 500 to 1700
mn/min, depending on the paper or board quality--and with optimum
utilization of the machine performance, with the probability of
production stoppages due to tearing of the sheet during production
being significantly reduced.
[0079] The smoothing pressure and calender pressure, in particular
nip pressure and line pressure conditions (or the line force) can
also be maintained in the ranges which are conventional per se or
even lower, for example from 10 to 500 kN/m (particularly from 10
to 300 kN/m for graphic papers) depending on the machine section,
for example from 20 to 200 kN/m in the calenders and from 100 to
500 kN/m during calendering, depending on the paper or board
quality (for example from 100 to 200 kN/m for writing and printing
paper, from 200 to 300 kN/m for art paper, from 400 to 500 kN/m for
capacitor paper); due to the fact that papers and boards with
optimum compressibility, crease tear and printability properties
are obtainable in accordance with the invention, the roll and
calender pressures can be reduced to a minimum, for example from 8
to 250 kN/m for graphic papers, for example from 15 to 150 kN/m in
the calenders and for example from 40 to 25b kN/m during
calendering, depending on the paper or board quality (for example
from 40 to 150 kN/m for writing and printing paper and from 120 to
250 kN/m for art paper).
[0080] The quality of the paper and board produced in accordance
with the invention is excellent, in particular if (W) is applied
before calendering. The compressibility and suitability as graphic
papers, in particular for writing and printing, particularly for
offset printing, is surprisingly good. The paper and board sheets
(B.sub.w) surface-finished with (L.sub.w) in accordance with the
invention are also very resistant to yellowing caused by the action
of light and/or heat, where, as antiyellowing agents, the surface
finishing agents (L.sub.w) in accordance with the invention have a
surprisingly good and durable action, even on use of very little
active substance (W) or (W.sub.1) (for example as is sufficient to
produce an also only unimolecular layer thickness).
[0081] Through use of solutions (L.sub.w) containing (W.sub.3), the
tear strength properties and freedom from picking or the smoothness
and the gloss can additionally be increased.
[0082] Particular colour effects and/or white effects can be
achieved using (W.sub.2)-containing solutions (L.sub.w). In
particular--if (W.sub.2) is a dye or dye mixture (W.sub.21)--paper
and board can be dyed with optimum dye yield; to this end, for
example, a suitable dyeing auxiliary [for example an electrolyte as
described above as diluent or (W.sub.4) and/or a levelling agent]
can, for example, also be added, for example to the dye-containing
solution (L.sub.w). Analogously, if (W.sub.2) is an optical
brightener (W.sub.22), optically brightened paper or optically
brightened board can be produced in optimum yield in this way.
[0083] Boards and papers (B.sub.w) which are distinguished by their
white quality and their wet tear resistance, and which (especially
the calendered ones) are distinguished by attractive gloss and
optimum surface and structure, in particular also by their
smoothness and compressibility, and by their suitability as graphic
paper, particularly also for intaglio printing and offset printing,
are obtainable in a very economical manner by the process according
to the invention and with the surface finishing agents (L.sub.w)
according to the invention. The wood-containing paper and board
sheets, in particular woodpulp-containing or lignin-continuing
paper or board sheets, which have been surface-treated with
(L.sub.w) in accordance with the invention and which are
distinguished by their high whitness stability, should also be
particularly emphasized.
[0084] The paper sheets and board sheets (B.sub.w) obtainable in
accordance with the invention by surface treatment of (B) with
(L.sub.w) as described are also a subject-matter of the invention,
in particular the smooth and preferably calendered papers,
especially graphic papers.
[0085] The paper or board sheets (B.sub.w) obtainable in accordance
with the. invention by surface treatment of (B) with (L.sub.w) can,
as conventional per se, be readied for further use, for example by
rolling up or cutting and then packing and supplied to the further
use in this form, in particular for writing, printing or graphic
processing in another manner, where they are also distinguished by
their dimensional stability. The paper or board sheets (B.sub.w)
are highly suitable as graphic papers and boards, i.e. as
substrates for graphic processing (particularly writing or
printing) by application of corresponding writing or printing inks
in the respective desired colours, types, application rates and
patterns by the application methods selected in each case in
accordance with the substrate and the desired effect. The papers
and boards (B.sub.w) (whether in cut form as paper sheets or
whether as a roll) are particularly suitable for printing, i.e. as
printing papers or boards, by any desired printing methods which
are conventional per se (principally letterpress printing,
planographic printing, intaglio printing and repro printing), where
they meet to a surprisingly high degree the requirements for
printing paper and board or for printability as defined in the 2nd
International Conference of the Specialist Graphic Institutes in
1953. Any desired suitable printing methods which are conventional
per se and correspond to the particular nature of (B) can be used
on the substrates (B.sub.w) according to the invention,
particularly letterpress printing, newspaper printing and generally
intaglio printing and offset printing, it being possible for
interfering phenomena, such as picking, deposits on the rubber
printing blanket and missing dots in intaglio printing to be
substantially prevented or reduced to a non-interfering minimum. It
is particularly worthy of mention that papers which are suitable
per se for intaglio printing [i.e. principally wood-containing or
lignin-containing types of paper containing at least 10% (for
example from 20 to 60%) of woodpulp and a high proportion of used
paper, also known as "natural intaglio printing, paper"] are also
highly suitable for offset printing if they have been
surface-treated with (L.sub.w) in accordance with the invention to
give papers (B.sub.w).
[0086] A further subject-matter of the invention is the process for
the production of paper or board which has been written on, printed
and/or graphically processed in another manner by application of at
least one graphic ink pattern to a substrate consisting of paper or
board, and drying, which is characterized in that the substrate
used for this purpose is paper or board (B.sub.w) which has been
surface-finishied with (L.sub.w) as described above.
[0087] Especially printing processes as mentioned above can be
used, principally intaglio printing, newspaper printing,
letterpress printing and offset printing in general. In particular,
a level, preferably size-free paper (B.sub.w) or a level,
preferably size-free board (B.sub.w) can be used as substrate both
for intaglio printing and for offset printing.
[0088] Printing can be carried out using any desired conventional
printing inks which contain constituents which are conventional per
se, essentially at least one dye and a suitable carrier or a
suitable binder and optionally additives. As dyes, principally
pigments (for example those as defined and also listed under
"Pigments" in the Colour Index), optionally combined with mineral
fillers, come into consideration, as usually employed in printing
inks; as binders, principally resins, which are advantageously
mixed with oils, come into consideration. The resins are mostly
alkyd resins and/or or phenyl-modified colophony resins and can, if
desired, be blended with further carrier substances, such as
suitable types of asphalt; as oils, oxidatively drying oils
(principally vegetable oils, in particular linseed oil or wood oil)
and physically drying mineral oils can be employed. As additives,
drying agents are advantageously employed, such as, for example,
tin, cobalt or manganese salts, for example manganese octanoate,
or/and optionally further additives, such as waxes. Such components
and additives or corresponding printing inks are known in general
terms and are described in large number in the specialist
literature, for example in EP-A-42515, 228372 and 666293. If
desired, however, water-borne printing inks can also be used, for
example those as described in EP-A-633143. The composition of such
printing inks is, for example,
[0089] 10-35% of colorant (consisting of 10-25% of pigment and
0-15% of mineral filler)
[0090] 20-73% of resins (if desired blended up to half with blend
substances, such as asphalt or oxidatively drying oils)
[0091] 15-60% of mineral oil
[0092] 2-12% of additives (for example drying agents and, if
desired, waxes).
[0093] For experimental purposes, it is also possible to use
standard printing inks, as also comiiercially available (for
example the test inks 40 8001 Inko.RTM. 11,2; 40 8002 Inko.RTM.
14,8; 40 8003 Inko.RTM. 19.5 and 40 8004 Inko.RTM. 25,0 from
Farbenfabriken Michael Huber, Munich, Germany).
[0094] Clear prints with optimum colour body and fastness and very
pure contours can be produced on the said substrates, with optimum
printing properties, in particular without interfering flaking
phenomena, ink deposits or missing dots or ink penetration.
[0095] In the following examples, the percentages denote percent by
weight and the temperatures are indicated in degrees Celsius;
"C.I." stands for "Colour Index". The polyethylene glycols employed
in the following examples are commercially available products which
are indicated with their average molecular weight and in which the
molecular weight distribution is 99.6% in the range from 0.4 to 2
times the stated molecular weight. The optical brightener C.I.
Fluorescent Brightener 321 employed is used in the form of an
aqueous 20% solution, and the amounts employed are based on this
form. The glyoxal crosslinking agent employed is used in the form
of an aqueous 42% solution, and the amounts employed are based on
this form. The papers employed in the following examples are those
produced in the paper mill and how they are employed in the
respective paper production step which corresponds to the following
examples.
[0096] The following solutions (L.sub.w) are employed:
[0097] Solution 1
[0098] 100 g of polyethylene glycol 4000 in 900 g of water.
[0099] Solution 2
[0100] 100 g of polyethylene glycol 4000 and 60 g of aqueous
glyoxal crosslinking agent (Cartabond TSI) in 1115 g of water.
Weight ratio between polyethylene glycol 4000 and glyoxal
crosslinkinig agent=4/1.
[0101] Solution 3
[0102] 100 g of polyethylene glycol 4000 and 500 g of C.I.
Fluorescent Brightener 321 in 1400 g of water.
[0103] Solution 4
[0104] 100 g of polyethylene glycol 2000 in 900 g of water
[0105] Solution 5
[0106] 100 g of polyethylene glycol 2000 and 500 g of C.I.
Fluorescent Brightener 32 1 in 1400 g of water
[0107] Solution 6
[0108] 100 g of polyethylene glycol 2000 and 79.3 g of aqueous
glyoxal crosslinking agent (Cartabond TSI) in 1153.7 g of water.
Weight ratio between polyethylene glycol 2000 and glyoxal
crosslinking agent=3/1.
[0109] Solution 7
[0110] 100 g of polyethylene glycol 4000, 120 g of aqueous glyoxal
crosslinking agent (Cartabond TSI) and 125 g of C.I. Fluorescent
Brightener 321 in 1655 g of water. Weight ratio between
polyethylene glycol 4000 and glyoxal crosslinking agent=2/1.
EXAMPLE 1
[0111] Paper used: uncalendered SCA paper produced in the paper
mill (natural intaglio printing paper with a basis weight of 56
g/m.sup.2; pulp composition: more than 80% of woodpulp and about
15-20% of chemical pulp, additionally containing 33% of kaolin as
filler, produced without used paper at pH 5.5, for calendering in a
supercalender).
[0112] The paper is cut into rectangles with a size of 1 m.sup.2
and tensioned on a flat surface. Solution 1 is sprayed uniformly
onto the paper at an application rate of 1.12 g/m.sup.2 of solution
1, which corresponds to a moistening of 14%, using a commercially
available airbrush paint gun into the tank of which the
corresponding amount of solution I had been introduced. The paper
surface-treated in this way is calendered in a laboratory calender
under the following conditions:
1 Roll surface temperature: 100.degree. C. Line force: 52 kN/m
Speed: 10 m/min Number of passages: 5
[0113] The application of polyethylene glycol 4000 is 0.112
g/m.sup.2, which corresponds to an application of 0.2% odry based
on fibre material. The paper is conditioned and tested for
mechanical and optical properties compared with a paper which has
been produced from the same SCA starting paper with the same amount
of distilled water instead of solution I in an otherwise identical
manner. The results of the comparative test are shown in Table I
below.
2 TABLE 1 SCA paper with SCA with distilled water Solution 1
(comparison) (Example 1) Smoothness (PPS roughness) in .mu.m 1.30
1.10 Gloss (Lehmann 75.degree.) 3.70 5.60 R 457 brightness with UV
68.3 69.5 R 457 brightness with UV 66.2 68.8 after exposure for 4
days Reflectance factor 73.5 74.2 Yellowness index 10.1 8.9 CIE
whiteness index 46.4 49.4 Visual assessment on the calender good
improved
EXAMPLE 2
[0114] Paper used: uncalendered SCB paper produced in the paper
mill (improved newsprinting paper with a basis weight of 60
g/m.sup.2; with a high used paper content and with calcium
carbonate as filler, produced at pH 7:2, for calendering in a
supercalender).
[0115] The paper is cut into rectangles with a size of 1 m.sup.2
and tensioned on a flat surface. Solution 1 is sprayed uniformly
onto the paper at an application rate of 1.8 g/m.sup.2 of solution
1, which corresponds to a moistening of 14%, using a commercially
available airbrush paint gun into whose tank the corresponding
amount of solution I had been introduced. The paper surface-treated
in this way is calendered in a laboratory calender under the
following conditions:
3 Roll surface temperature: 100.degree. C. Line force: 52 kN/m
Speed: 10 m/min Number of passages: 5
[0116] The application of polyethylene glycol 4000 is 0.18
g/m.sup.2, which corresponds to an application of 0.3% odry based
on fibre material.
EXAMPLE 3
[0117] The procedure is the same as described in Example 2, with
the difference that instead of solution 1, the same amount of
solution 2 is applied.
EXAMPLE 4
[0118] The procedure is the same as described in Example 2, with
the difference that instead of solution 1, the same amount of
solution 3 is applied.
[0119] The SCB papers treated in Examples 2, 3 and 4 are
conditioned and calendered as in Examples 1 and 2 and then tested
for mechanical and optical properties compared with a paper
produced from the same SCB starting paper with the same amount of
distilled water instead of solution 1, 2 or 3 in an otherwise
identical manner. The results of the comparative tests arc shown in
Table 2 below.
4 TABLE 2 SCB paper with SCB paper SCB paper SCB paper distilled
water with solution 1 with solution 2 with solution 3 (comparison)
(Example 2) (Example 3) (Example 4) Smoothness (PPS 1.23 1.07 1.10
1.12 roughness) in .mu.m Gloss (Lehmann 75.degree.) 3.50 5.0 4.0
4.1 R 457 brightness without 66.1 67.0 66.8 67.2 UV R 457
brightness with UV 67.7 68.2 67.9 70.8 R 457 brightness with UV
65.1 67.1 66.3 69.5 after exposure for 4 days Reflectance factor
71.8 72.5 71.9 72.9 Visual assessment on the slight sticking to the
very good very good good sheet calender calender sheet delivery
sheet delivery delivery
EXAMPLE 5
[0120] Paper used: wood-containing (=w.c.) base paper for coating,
produced in the paper mill (with a basis weight of 36 g/m.sup.2;
pulp composition: 60% of woodpulp and 40% of chemical pull),
additionally containing 9.5% of filler).
[0121] The paper is cut into rectangles with a size of 1 m.sup.2
and tensioned on a flat surface. Solution 4 is sprayed uniformly
onto the paper at an application rate of 0.729 g/m.sup.2 of
solution 4, which corresponds to a moistening of 14%, using a
commercially available airbrushl paint gull into whose tank the
corresponding amount of solution 4 had been introduced. The paper
surface-treated in this way is calendered in a laboratory calender
under the following conditions:
5 Roll surface temperature: 100.degree. C. Line force: 52 kN/m
Speed: 10 m/min Number of passages: 1
[0122] The application of polyethylene glycol 2000 is 0.072
g/m.sup.2, which corresponds to an application of 0.2% odry based
on fibre material.
EXAMPLE 6
[0123] The procedure is the same as described in Example 5, with
the difference that instead of solution 4, the same amount of
solution 5 is applied.
EXAMPLE 7
[0124] The procedure is the same as described in Example 5, with
the difference that instead of solution 4, the same amount of
solution 6 is applied.
[0125] The papers treated in Examples 5, 6 and 7 are conditioned,
smoothed and tested for optical properties compared with a paper
produced from the same SCB starting paper with the same amount of
distilled water instead of solution 1, 2 or 3, in an otherwise
identical manner. The results of the comparative tests are shown in
Table 3 below.
6 TABLE 3 w.c. base paper for w.c. base paper w.c. base paper w.c.
base paper coating, with for coating, for coating, for coating,
distilled water with solution 4 with solution 5 with solution 6
(comparison) (Example 5) (Example 6) (Example 7) R 457 brightness
68.1 68.4 68.9 68.2 without UV R 457 brightness 69.1 69.8 71.1 69.3
with UV Reflectance factor 73.0 73.6 74.2 73.4 R 457 brightness
67.8 68.5 70.6 68.1 without UV after exposure for 4 days R 457
brightness 65.1 66.7 68.4 66.4 without UV after heating at
100.degree. C. for 2 hours
EXAMPLE 8
[0126] Paper used: wood-free (=w.f.) coated base paper produced in
the paper mill (with a basis -weight of 80 g/m.sup.2; containing
12% of Filler).
[0127] The paper is cut into rectangles with a size of 1 m.sup.2
and tensioned on a flat surface. Solution 4 is sprayed uniformly
onto the paper at an application rate of 1.2 g/m.sup.2 of solution
4, which corresponds to a moistening of 14%, using a commercially
available airbrush paint gun into whose tank the corresponding
amount of solution 4 had been introduced. The paper surface-treated
in this way is calendered in a laboratory calender under the
following conditions:
[0128] Roll surface temperature: 100.degree. C.
[0129] Line force: 52 kN/m
[0130] Speed: 10 m/min
[0131] Number of passages:
[0132] The application of polyethylene glycol 2000 is 0.12
g/m.sup.2, which corresponds to an application of 0.15% odry based
on fibre material.
[0133] The w.f. paper treated in Example 8 is conditioned, smoothed
and tested for optical properties compared with a paper produced
from the same w.f. starting paper with the same amount of distilled
water instead of solution 4, in an otherwise identical manner. The
results of the comparative test are shown in Table 4 below.
7 TABLE 4 w.f. base paper for w.f. base paper for coating, with
distilled coating, with solution water (comparison) 4 (Example 8) R
457 brightness without 86.2 87.1 UV Reflectance factor 88.1 89.2 R
457 brightness 85.5 86.7 without UV after exposure for 4 days R 457
brightness 83.1 84.8 without UV after heating at 100.degree. C. for
2 hours Reflectance factor after 87.0 88.7 heating at 100.degree.
C. for 2 hours
[0134] The tests carried out in the examples are carried out in
accordance with the following specifications:
[0135] Determination of the weight per unit area (basis weight) of
paper and cardboard in accordance with DIN specification=ISO
536;
[0136] Parker-Print-surf (PPS) roughness in accordance with BS 6563
(1985);
[0137] Lehmann 75.degree. gloss;
[0138] R 457 brightness-in accordance with DUN 53245, Parts
1+2;
[0139] Reflectance factor DUN 53145, Part 1;
[0140] Yellowness index DIN 53145.
EXAMPLE 9
[0141] Paper used: uncalendered SC-A paper produced in the paper
mill (natural intaglio printing paper with a basis weight of 56
g/m.sup.2; pulp composition: >70% of woodpulp and about 15 of
gray paper in the forin of DIP (deinked paper) and 12-15% of
chemical pulp, additionally containing 33% of kaolin as filler,
produced without used paper at pH 6.8, for calendering in a
supercalender).
[0142] The paper is rolled up on rolls with 80 cm breadth and
packed. In a pilot plant corresponding to large scale conditions,
solution 7 is applied at a paper speed of 800 m/min. in the
following concentration
[0143] 0% (=only water) which is the blanc
[0144] 8% Solution 7 (=0.4% polyethylene glycol 4000)
[0145] The so treated paper is calendered in a calender by the
Janus principle (Producer Voith Sulzer Krefeld) with 10
plastic-crowned rolls at a temperature of 130.degree. C. and a
speed of 1200 m/min. and under the following calendering
conditions:
[0146] A load 300 KN/m, with and without steam dampening
[0147] B load 400 KN/m, with and without steam dampening
[0148] the following results are obtained
8TABLE 5 Sample Gardner gloss calender blackening load in KN/m
Blanc 53.2 54.9 400 SC-A paper with 53.3 52.8 300 solution 7
[0149] from which results that
[0150] 1) at a same gloss improved calender blackening values
result
[0151] 2) at a same gloss the calender load may be substantially
lowered, which leads to improved properties (folding endurance,
opacity, lightness) of the calendered paper
PRINT EXAMPLES
Print Example A
[0152] An intaglio test printing machine [Testacolor, Prufbau
Einlehner (System Haindl)] [A. Brennig--Comparison of two different
intaglio test printing machines--Wochenblatt fur Papierfrber, 106,
pp. 301-304 (1978) No. 8]
[0153] 2 cylinders are available for the intaglio test printing
machine, namely:
[0154] a) conventionally etched
[0155] b) electromechanically engraved.
[0156] The viscosity setting of the ink is tested using a Ford cup.
The intaglio print is assessed for
[0157] print gloss
[0158] missing dots
[0159] blackening.
[0160] The optical classification of the intaglio printing test
prints in full tone, half tone and perfecting print shows that
using the paper produced in accordance with Example 1, the print
gloss (measured using a Zeiss goniophotometer on printed full-tone
areas) is increased by 27% compared witlh the corresponding
untreated paper and using the paper produced in accordance with
Example 2, the print gloss is increased by 23% compared with the
corresponding untreated paper.
[0161] Visual assessment for missing dots shows that the prints on
papers produced in accordance with Example 1 and 2 have
significantly fewer missing dots than the corresponding prints
produced b) comparison on the corresponding untreated comparative
papers.
Print Example B
[0162] Using test inks 40 8001 Inko 11,2 and 40 8002 Inko 14,8 from
Farbenfabriken Michael Huber Munich, papers produced in accordance
with Example 3 are printed in comparison with untreated paper in
accordance with the "picking test" working instructions from
Farbenfabriken Michael Huber Munich using the following data on the
offset test printing unit from Prufbau (Germany):
9 Ink supply for inking unit Natural papers 0.4 cm.sup.3 (rubber
plate) Inking time 30 seconds Contact pressure during printing
Metal plate 20 kN/m Rubber plate 10 kN/m Printing plate width 2 or
4 cm Printing speed 0-4 m/sec (pendulum or with spring
tension).
[0163] The first visible damage to the ink film is assessed as
commencement of picking. The paper produced in accordance with
Example 3 has significantly better behaviour in the picking test
with both test inks compared with the corresponding untreated
comparative paper.
* * * * *