U.S. patent application number 13/811613 was filed with the patent office on 2013-05-16 for method for preparing white paper.
This patent application is currently assigned to CLARIANT FINANCE (BVI) LIMITED. The applicant listed for this patent is David Atkinson, Heidrun Grether-Schene, Andrew Clive Jackson, Cedric Klein, Frederic Reveaud. Invention is credited to David Atkinson, Heidrun Grether-Schene, Andrew Clive Jackson, Cedric Klein, Frederic Reveaud.
Application Number | 20130118698 13/811613 |
Document ID | / |
Family ID | 44581139 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130118698 |
Kind Code |
A1 |
Grether-Schene; Heidrun ; et
al. |
May 16, 2013 |
Method for Preparing White Paper
Abstract
Object of the invention is the method for preparing white paper
which comprises adding to the pulp mass an aqueous formulation
comprising a) at least one optical brightener of formula (I)
##STR00001## in which the anionic charge on the brightener is
balanced by a cationic charge composed of one or more identical or
different cations selected from the group consisting of hydrogen,
an alkali metal cation, alkaline earth metal, ammonium, ammonium
which is mono-, di-, tri- or tetrasubstituted by a C.sub.1-C.sub.4
linear or branched alkyl radical, ammonium which is mono-, di-,
tri- or tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium which is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical or
mixtures of said compounds, wherein R.sub.1 and R.sub.1' may be the
same or different, and each is hydrogen, C.sub.1-C.sub.4 linear or
branched alkyl, C.sub.2-C.sub.4 linear or branched hydroxyalkyl,
CH.sub.2CO.sub.2.sup.-, CH.sub.2CH.sub.2CONH.sub.2 or
CH.sub.2CH.sub.2CN, R.sub.2 and R.sub.2' may be the same or
different, and each is C.sub.1-C.sub.4 linear or branched alkyl,
C.sub.2-C.sub.4 linear or branched hydroxyalkyl,
CH.sub.2CO.sub.2.sup.-, CH(CO.sub.2.sup.-)CH.sub.2CO.sub.2.sup.-,
CH(CO.sub.2.sup.-)CH.sub.2CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2SO.sub.3.sup.-, CH.sub.2CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH(CH.sub.3)CO.sub.2.sup.-, benzyl, or R.sub.1 and R.sub.2
and/or R.sub.1' and R.sub.2', together with the neighboring
nitrogen atom signify a morpholine ring; R.sub.3 signifies
hydrogen, --CO.sub.2.sup.- or --SO.sub.3.sup.- and p is 0, 1 or 2,
and b) at least one shading dye of formula (II) ##STR00002## in
which R.sub.4 signifies H, methyl or ethyl, R.sub.5 signifies
paramethoxyphenyl, methyl or ethyl, M signifies a cation selected
from the group consisting of hydrogen, an alkali metal cation,
alkaline earth metal, ammonium, ammonium which is mono-, di-, tri-
or tetrasubstituted by a C.sub.1-C.sub.4 linear or branched alkyl
radical, ammonium which is mono-, di-, tri- or tetrasubstituted by
a C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical, ammonium
which is, di-, tri- or tetrasubstituted by a mixture of
C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical or mixtures of said compounds, c)
optionally one or more auxiliaries and d) water.
Inventors: |
Grether-Schene; Heidrun;
(Efringen-Kirchen, DE) ; Klein; Cedric; (Brumath,
FR) ; Reveaud; Frederic; (Mulhouse, FR) ;
Atkinson; David; (Arlesheim BL, CH) ; Jackson; Andrew
Clive; (Muenchenstein BL, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Grether-Schene; Heidrun
Klein; Cedric
Reveaud; Frederic
Atkinson; David
Jackson; Andrew Clive |
Efringen-Kirchen
Brumath
Mulhouse
Arlesheim BL
Muenchenstein BL |
|
DE
FR
FR
CH
CH |
|
|
Assignee: |
CLARIANT FINANCE (BVI)
LIMITED
Tortola
VG
|
Family ID: |
44581139 |
Appl. No.: |
13/811613 |
Filed: |
July 22, 2011 |
PCT Filed: |
July 22, 2011 |
PCT NO: |
PCT/EP2011/003692 |
371 Date: |
January 22, 2013 |
Current U.S.
Class: |
162/162 |
Current CPC
Class: |
D21H 21/32 20130101;
D21H 21/30 20130101; D21H 21/28 20130101; D21H 17/09 20130101 |
Class at
Publication: |
162/162 |
International
Class: |
D21H 17/09 20060101
D21H017/09 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 23, 2010 |
EP |
10007659.5 |
Jun 29, 2011 |
EP |
11005290.9 |
Claims
1. A method for preparing white paper which comprising the step of
adding to the pulp mass an aqueous formulation comprising: a) at
least one optical brightener of formula (I) ##STR00011## the
anionic charge on the at least one optical brightener is balanced
by a cationic charge including of one or more identical or
different cations selected from the group consisting of hydrogen,
an alkali metal cation, alkaline earth metal, ammonium, ammonium
that is mono-, di-, tri- or tetrasubstituted by a C.sub.1-C.sub.4
linear or branched alkyl radical, ammonium that is mono-, di-, tri-
or tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium that is di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical and
mixtures thereof, and b) at least one shading dye of formula (II)
##STR00012## c) optionally one or more auxiliaries and d)
water.
2. A method according to claim 1, wherein in the at least one
optical brightener of formula (I) R.sub.3 is --SO.sub.3.sup.- and p
is 1 and the --SO.sub.3.sup.- group is in the 4-position of the
phenyl ring.
3. The method according to claim 1, wherein in the at least one
optical brightener formula (I), R.sub.3 is --SO.sub.3.sup.-, p is 2
and the --SO.sub.3.sup.- groups are in the 2,5-positions of the
phenyl ring.
4. The method according to claim 1, wherein in the at least one
optical brightener of formula (I), R.sub.3 is --CO.sub.2hu -, p is
1 and the --CO.sub.2.sup.- group is in the 2 or 4 position of the
phenyl ring.
5. The method according to claim 1, wherein in the at least one
optical brightener of formula (I) the anionic charge on the at
least one optical brightener is balanced by a cationic charge
including one or more identical or different cations selected from
the group consisting of hydrogen, an alkali metal cation, alkaline
earth metal, ammonium that is mono-, di-, tri- or tetrasubstituted
by a C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical,
ammonium which that is, di-, tri- or tetrasubstituted by a mixture
of C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical and mixtures thereof, and R.sub.1 and
R.sub.1' are the same or different, and each is hydrogen,
C.sub.1-C.sub.4 linear or branched alkyl, C.sub.2-C.sub.4 linear or
branched hydroxyalkyl, CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2CONH.sub.2 or CH.sub.2CH.sub.2CN, and R.sub.2 and
R.sub.2' are the same or different, and each is C.sub.1-C.sub.4
linear or branched alkyl, C.sub.2-C.sub.4 linear or branched
hydroxyalkyl, CH.sub.2CO.sub.2.sup.-, CH(CO.sub.2)CH.sub.2CO.sub.2
or CH.sub.2CH.sub.2SO.sub.3.sup.-, R.sub.3 is hydrogen,
--CO.sub.2.sup.- or --SO.sub.3.sup.- and p is 0, 1 or 2.
6. The method according to claim 1, wherein in the at least one
optical brightener of formula (I) the anionic charge on the at
least one optical brightener is balanced by a cationic charge
including one or more identical or different cations selected from
the group consisting of Li.sup.+, Na.sup.+, K.sup.+, Ca.sup.2+,
Mg.sup.2+, ammonium that is mono-, di-, tri- or tetrasubstituted by
a C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical, ammonium
that is, di-, tri- or tetrasubstituted by a mixture of
C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical and mixtures thereof, R.sub.1 and
R.sub.1' are the same or different, and each is hydrogen, methyl,
ethyl, propyl, .alpha.-methylpropyl, .beta.-methylpropyl,
.beta.-hydroxyethyl, .beta.-hydroxypropyl, CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2CONH.sub.2 or CH.sub.2CH.sub.2CN, R.sub.2 and
R.sub.2' are the same or different, and each is methyl, ethyl,
propyl, .alpha.-methylpropyl, .beta.-methylpropyl,
.beta.-hydroxyethyl, .beta.-hydroxypropyl, CH.sub.2CO.sub.2.sup.-,
CH(CO.sub.2.sup.-)CH.sub.2CO.sub.2.sup.- or
CH.sub.2CH.sub.2SO.sub.3.sup.-, R.sub.3 is hydrogen,
--CO.sub.2.sup.- or --SO.sub.3.sup.- and p is 0, 1 or 2.
7. The method according to claim 1, wherein in the at least one
optical brightener of formula (I) the anionic charge on the
brightener is balanced by a cationic charge including one or more
identical or different cations selected from the group consisting
of Na.sup.+, K.sup.+, triethanolammonium,
N-hydroxyethyl-N,N-dimethylammonium,
N-hydroxyethyl-N,N-diethylammonium and mixtures thereof, R.sub.1
and R.sub.1' are the same or different, and each is hydrogen,
ethyl, propyl, .beta.-hydroxyethyl, .beta.-hydroxypropyl,
CH.sub.2CO.sub.2.sup.-, or CH.sub.2CH.sub.2CONH.sub.2, R.sub.2 and
R.sub.2' are the same or different, and each is ethyl, propyl,
.beta.-hydroxyethyl, .beta.-hydroxypropyl, CH.sub.2CO.sub.2.sup.-,
CH(CO.sub.2)CH.sub.2CO.sub.2.sup.- or
CH.sub.2CH.sub.2SO.sub.3.sup.- and R.sub.3 is hydrogen,
--CO.sub.2.sup.- or --SO.sub.3.sup.- and p is 0 or 1.
8. The method according to claim 1, wherein the at least one
optical brightener of formula (I) is used in an amount from 0.001
to 5% by weight, the % by weight being based on the total weight of
dry pulp.
9. The method according to claim 1, wherein in the at least one
optical brightener of formula (II) R.sub.4 is H, methyl or ethyl,
R.sub.5 is paramethoxyphenyl, methyl or ethyl, M is a cation
selected from the group consisting of hydrogen, an alkali metal
cation, alkaline earth metal, ammonium that is mono-, di-, tri- or
tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium that is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical and
mixtures thereof.
10. The method according to claim 1, wherein in the at least one
shading dye of formula (II) R.sub.4 is methyl or ethyl, R.sub.5 is
methyl or ethyl, M is a cation selected from the group consisting
of Li.sup.+, Na.sup.+, K.sup.+, 1/2 Ca.sup.2+, 1/2 Mg.sup.2+,
ammonium that is mono-, di-, tri- or tetrasubstituted by a
C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical, ammonium
that is di-, tri- or tetrasubstituted by a mixture of
C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical and mixtures thereof.
11. The method according to claim 1, wherein in the at least one
shading dye of formula (II) R.sub.4 is methyl or ethyl, R.sub.5 is
methyl or ethyl, M is a cation selected from the group consisting
of Na.sup.+, K.sup.+, triethanolammonium,
N-hydroxyethyl-N,N-dimethylammonium,
N-hydroxyethyl-N,N-diethylammonium and mixtures thereof.
12. The method according to claim 1, wherein the at least one
shading dye of formula (II) is used in an amount from 0.0001 to
0.02% by weight, the % by weight being based on the total weight of
dry pulp.
13. The method according to claim 1, wherein the aqueous
formulation contains one or more auxiliaries selected from the
group consisting of antifreezers, dispersing agents, synthetic or
natural thickeners, carriers, defoamers, wax emulsions, dyes,
inorganic salts, solubilizing aids, preservatives, complexing
agents, biocides, cross-linkers, pigments and special resins.
14. The method according to claim 1, wherein the adding step
further comprises mixing the at least one optical brightener of
formula (I), the at least one shading dye of formula (II) and
optionally one or more auxiliaries, wherein the at least one
optical brightener, the at least one shading dye and the optional
one or more auxiliaries are solids or preformed aqueous
solutions.
15. The method according to claim 14, wherein in the aqueous
solution, the concentration of compound of formula (I) in water is
of from 1 to 50% by weight, the % by weight being based on the
total weight of the preformed aqueous solution containing the at
least one optical brightener of formula (I).
16. The method according to claim 14, wherein in the aqueous
solution, the concentration of the at least one shading dye of
formula (II) in water is from 0.001 to 30% by weight, the % by
weight being based on the total weight of the preformed aqueous
solution containing the the at least one shading dye of formula
(II).
17. The method according to claim 14, wherein the pH value of the
aqueous formulation is in the range of from 5 to 13.
18. The method according to claim 1, wherein the at least one
optical brightener of formula (I) is used in an amount from 0.01 to
3% by weight, the % by weight being based on the total weight of
dry pulp.
19. The method according to claim 1, wherein the at least one
shading dye of formula (II) is used in an amount from 0.0005 to
0.01% by weight, the % by weight being based on the total weight of
dry pulp.
Description
[0001] The instant invention relates to a method for preparing
white paper which comprises adding to the pulp mass an aqueous
formulation consisting essentially of derivatives of
diaminostilbene optical brighteners, shading dyes, optionally
auxiliaries, and water.
BACKGROUND OF THE INVENTION
[0002] It is well known that the whiteness and thereby the
attractiveness of papers can be improved by the addition of optical
brighteners and shading dyes to the pulp mass prior to sheet
formation.
[0003] However, the decrease of the brightness while using shading
dyes is a widely known problem.
[0004] WO 0218705 A1 however teaches that the use of shading dyes,
while having a positive effect on whiteness, has a negative impact
on brightness. The solution to this problem is to add additional
optical brightener, the advantage claimed in WO 0218705 A1 being
characterized by the use of a mixture comprising at least one
direct dye (exemplified by C.I. Direct Violet 35) and at least one
optical brightener.
[0005] Surprisingly, we have now discovered certain shading dyes
which have a strongly positive effect on whiteness while having
little or no effect on brightness, and which can be used in aqueous
formulations comprising optical brighteners, optionally
auxiliaries, and water in order to enable the papermaker to reach
high levels of whiteness and brightness.
[0006] Therefore, the goal of the present invention is to provide a
method for preparing white paper which comprises adding to the pulp
mass an aqueous formulation containing derivatives of
diaminostilbene optical brighteners, certain shading dyes,
optionally auxiliaries, and water. The paper prepared according to
the present invention affords enhanced high whiteness levels while
avoiding the disadvantages characterized by the use of shading dyes
(loss of brightness) or pigments (lower whiteness build) recognized
as being state-of-the-art.
DESCRIPTION OF THE INVENTION
[0007] The present invention therefore provides a method for
preparing white paper which comprises adding to the pulp mass an
aqueous formulation comprising [0008] (a) at least one optical
brightener of formula (I)
[0008] ##STR00003## [0009] in which [0010] the anionic charge on
the brightener is balanced by a cationic charge composed of one or
more identical or different cations selected from the group
consisting of hydrogen, an alkali metal cation, alkaline earth
metal, ammonium, ammonium which is mono-, di-, tri- or
tetrasubstituted by a C.sub.1-C.sub.4 linear or branched alkyl
radical, ammonium which is mono-, di-, tri- or tetrasubstituted by
a C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical, ammonium
which is, di-, tri- or tetrasubstituted by a mixture of
C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical or mixtures of said compounds, [0011]
R.sub.1 and R.sub.1' may be the same or different, and each is
hydrogen, C.sub.1-C.sub.4 linear or branched alkyl, C.sub.2-C.sub.4
linear or branched hydroxyalkyl, CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2CONH.sub.2 or CH.sub.2CH.sub.2CN, [0012] R.sub.2
and R.sub.2' may be the same or different, and each is
C.sub.1-C.sub.4 linear or branched alkyl, C.sub.2-C.sub.4 linear or
branched hydroxyalkyl, CH.sub.2CO.sub.2.sup.-,
CH(CO.sub.2)CH.sub.2CO.sub.2,
CH(CO.sub.2)CH.sub.2CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2SO.sub.3.sup.-, CH.sub.2CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH(CH.sub.3)CO.sub.2.sup.-, benzyl, or [0013] R.sub.1 and
R.sub.2 and/or R.sub.1' and R.sub.2', together with the neighboring
nitrogen atom signify a morpholine ring [0014] R.sub.3 signify
hydrogen, --CO.sub.2 or --SO.sub.3.sup.- and [0015] p is 0, 1 or 2,
[0016] (b) at least one shading dye of formula (II)
[0016] ##STR00004## [0017] in which [0018] R.sub.4 signifies H,
methyl or ethyl, [0019] R.sub.5 signifies paramethoxyphenyl, methyl
or ethyl, [0020] M signifies a cation selected from the group
consisting of hydrogen, an alkali metal cation, alkaline earth
metal, ammonium, ammonium which is mono-, di-, tri- or
tetrasubstituted by a C.sub.1-C.sub.4 linear or branched alkyl
radical, ammonium which is mono-, di-, tri- or tetrasubstituted by
a C.sub.1-C.sub.4 linear or branched hydroxyalkyl radical, ammonium
which is, di-, tri- or tetrasubstituted by a mixture of
C.sub.1-C.sub.4 linear or branched alkylradical and linear or
branched hydroxyalkyl radical or mixtures of said compounds, [0021]
(c) optionally one or more auxiliaries and [0022] (d) water.
[0023] In compounds of formula (I) in which R.sub.3 is
--SO.sub.3.sup.- and p is 1, the --SO.sub.3.sup.- group is
preferably in the 4-position of the phenyl ring.
[0024] In compounds of formula (I) in which R.sub.3 is
--SO.sub.3.sup.- and p is 2, the --SO.sub.3.sup.- groups are
preferably in the 2,5-positions of the phenyl ring.
[0025] In compounds of formula (I) in which R.sub.3 is
--CO.sub.2.sup.- and p is 1, the --CO.sub.2.sup.- group is
preferably in the 2 or 4 position of the phenyl ring.
[0026] Preferred compounds of formula (I) are those in which
[0027] the anionic charge on the brightener is balanced by a
cationic charge composed of one or more identical or different
cations selected from the group consisting of hydrogen, an alkali
metal cation, alkaline earth metal, ammonium which is mono-, di-,
tri- or tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium which is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical or
mixtures of said compounds, [0028] R.sub.1 and R.sub.1' may be the
same or different, and each is hydrogen, C.sub.1-C.sub.4 linear or
branched alkyl, C.sub.2-C.sub.4 linear or branched hydroxyalkyl,
CH.sub.2CO.sub.2.sup.-, CH.sub.2CH.sub.2CONH.sub.2 or
CH.sub.2CH.sub.2CN, [0029] R.sub.2 and R.sub.2' may be the same or
different, and each is C.sub.1-C.sub.4 linear or branched alkyl,
C.sub.2-C.sub.4 linear or branched hydroxyalkyl,
CH.sub.2CO.sub.2.sup.-, CH(CO.sub.2.sup.-)CH.sub.2CO.sub.2.sup.- or
CH.sub.2CH.sub.2SO.sub.3.sup.-, [0030] R.sub.3 signify hydrogen,
--CO.sub.2.sup.- or --SO.sub.3.sup.- and [0031] p is 0, 1 or 2.
[0032] More preferred compounds of formula (I) are those in
which
[0033] the anionic charge on the brightener is balanced by a
cationic charge composed of one or more identical or different
cations selected from the group consisting of Li.sup.+, Na.sup.+,
K.sup.+, Ca.sup.2+, Mg.sup.2+, ammonium which is mono-, di-, tri-
or tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium which is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical or
mixtures of said compounds, [0034] R.sub.1 and R.sub.1' may be the
same or different, and each is hydrogen, methyl, ethyl, propyl,
.alpha.-methylpropyl, .beta.-methylpropyl, .beta.-hydroxyethyl,
.beta.-hydroxypropyl, CH.sub.2CO.sub.2.sup.-,
CH.sub.2CH.sub.2CONH.sub.2 or CH.sub.2CH.sub.2CN, [0035] R.sub.2
and R.sub.2' may be the same or different, and each is methyl,
ethyl, propyl, .alpha.-methylpropyl, .beta.-methylpropyl,
.beta.-hydroxyethyl, .beta.-hydroxypropyl, CH.sub.2CO.sub.2.sup.-,
CH(CO.sub.2.sup.-)CH.sub.2CO.sub.2.sup.- or
CH.sub.2CH.sub.2SO.sub.3.sup.-, [0036] R.sub.3 signify hydrogen,
--CO.sub.2.sup.- or --SO.sub.3.sup.- and [0037] p is 0, 1 or 2.
[0038] Especially preferred compounds of formula (I) are those in
which
[0039] the anionic charge on the brightener is balanced by a
cationic charge composed of one or more identical or different
cations selected from the group consisting of Na.sup.+, K.sup.+,
triethanolammonium, N-hydroxyethyl-N,N-dimethylammonium,
N-hydroxyethyl-N,N-diethylammonium or mixtures of said compounds,
[0040] R.sub.1 and R.sub.1' may be the same or different, and each
is hydrogen, ethyl, propyl, 3-hydroxyethyl, p-hydroxypropyl,
CH.sub.2CO.sub.2.sup.-, or CH.sub.2CH.sub.2CONH.sub.2, [0041]
R.sub.2 and R.sub.2' may be the same or different, and each is
ethyl, propyl, .beta.-hydroxyethyl, .beta.-hydroxypropyl,
CH.sub.2CO.sub.2.sup.-, CH(CO.sub.2.sup.-)CH.sub.2CO.sub.2.sup.-,
or CH.sub.2CH.sub.2SO.sub.3.sup.- and [0042] R.sub.3 signify
hydrogen, --CO.sub.2.sup.- or --SO.sub.3.sup.- and [0043] p is 0 or
1.
[0044] Compound of formula (I) is used in an amount typically of
from 0.001 to 5% by weight, preferably in the range of from 0.01 to
3% by weight, the % by weight being based on the total weight of
dry pulp.
[0045] Preferred compounds of formula (U) are those in which [0046]
R.sub.4 signifies H, methyl or ethyl, [0047] R.sub.5 signifies
paramethoxyphenyl, methyl or ethyl, [0048] M signifies a cation
selected from the group consisting of hydrogen, an alkali metal
cation, alkaline earth metal, ammonium which is mono-, di-, tri- or
tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium which is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical or
mixtures of said compounds.
[0049] More preferred compounds of formula (II) are those in which
[0050] R.sub.4 signifies methyl or ethyl, [0051] R.sub.5 signifies
methyl or ethyl, [0052] M signifies a cation selected from the
group consisting of Li.sup.+, Na.sup.+, K.sup.+, 1/2Ca.sup.2+,
1/2Mg.sup.2+, ammonium which is mono-, di-, tri- or
tetrasubstituted by a C.sub.1-C.sub.4 linear or branched
hydroxyalkyl radical, ammonium which is, di-, tri- or
tetrasubstituted by a mixture of C.sub.1-C.sub.4 linear or branched
alkylradical and linear or branched hydroxyalkyl radical or
mixtures of said compounds.
[0053] Especially preferred compounds of formula (U) are those in
which [0054] R.sub.4 signifies methyl or ethyl, [0055] R.sub.5
signifies methyl or ethyl, [0056] M signifies a cation selected
from the group consisting of Na.sup.+, K.sup.+, triethanolammonium,
N-hydroxyethyl-N,N-dimethylammonium,
N-hydroxyethyl-N,N-diethylammonium or mixtures of said
compounds.
[0057] Compound of formula (II) is used in an amount typically of
from 0.0001 to 0.02% by weight, preferably in the range of from
0.0005 to 0.01% by weight, the % by weight being based on the total
weight of dry pulp.
[0058] The fibres in the pulp mass may be sourced from hardwood
and/or softwood trees, and may comprise virgin fibres and/or
recycled fibres. The fibres may be bleached or unbleached.
[0059] In addition to one or more compounds of formula (I), one or
more compounds of formula (II) and water, the aqueous formulation
may optionally contain one or more auxiliaries. Examples of such
auxiliaries are for example antifreezers, dispersing agents,
synthetic or natural thickeners, carriers, defoamers, wax
emulsions, dyes, inorganic salts, solubilizing aids, preservatives,
complexing agents, biocides, cross-linkers, pigments, special
resins etc.
[0060] In addition to one or more compounds of formula (I), one or
more compounds of formula (II), optionally one or more auxiliaries
and water, the aqueous formulation may contain by-products formed
during the preparation of compounds of formula (I) and compounds of
formula (II).
[0061] The aqueous formulation may be prepared by mixing one or
more compounds of formula (I), one or more compounds of formula
(II) and optionally one or more auxiliaries as solids or as
preformed aqueous solutions.
[0062] One or more compounds of formula (I), one or more compounds
of formula (II), optionally one or more auxiliaries and water can
be mixed in any order or at the same time to form the aqueous
formulation.
[0063] Preferably, one or more compounds of formula (II),
optionally one or more auxiliaries and water are added to a
preformed aqueous solution containing one or more compounds of
formula (I) to form the aqueous formulation.
[0064] When used as a preformed aqueous solution, the concentration
of compound of formula (I) in water is preferably of from 1 to 50%
by weight, more preferably of from 2 to 40% by weight, even more
preferably from 10 to 30% by weight, the % by weight being based on
the total weight of the preformed aqueous solution containing the
compound of formula (I).
[0065] When used as a preformed aqueous solution, the concentration
of compound of formula (II) in water is preferably of from 0.001 to
30% by weight, more preferably of from 0.01 to 25% by weight, even
more preferably from 0.02 to 20% by weight, the % by weight being
based on the total weight of the preformed aqueous solution
containing the compound of formula (II).
[0066] The pH value of the aqueous formulation is typically in the
range of from 5 to 13, preferably of from 6 to 11, more preferably
of from 7 to 10. Where it is necessary to adjust the pH of the
aqueous formulation, acids or bases may be employed. Examples of
acids which may be employed include but are not restricted to
hydrochloric acid, sulphuric acid, formic acid and acetic acid.
Examples of bases which may be employed include but are not
restricted to alkali metal and alkaline earth metal hydroxide or
carbonates, ammonia or amines.
[0067] The present invention further provides a method for
preparing white paper characterized in that the aqueous formulation
containing one or more compounds of formula (I), one or more
compounds of formula (II), optionally one or more auxiliaries and
water is used.
[0068] The present invention therefore provides a method for
preparing white paper characterized in that the aqueous formulation
containing one or more compounds of formula (I), one or more
compounds of formula (II), optionally one or more auxiliaries and
water is added to the pulp mass prior to sheet formation.
[0069] The following examples shall demonstrate the instant
invention in more details. In the present application, if not
indicated otherwise, "parts" means "parts by weight" and "%" means
"% by weight".
EXAMPLES
Preparative Example 1
[0070] An aqueous solution (S1) is prepared by slowly adding 79
parts of water to 921 parts of a preformed aqueous solution
containing 0.216 mol per kg of compound of formula (1) (synthesized
according to example 1 in GB 1114021 with the sole difference that
the final solution was ultra-filtered to remove salts and
concentrated to 0.216 mol per kg of compound of formula (1)) at
room temperature with efficient stirring. The obtained mixture is
stirred for 1 hour at room temperature to afford 1000 parts of an
aqueous solution (S1) containing 0.199 mol per kg of compound of
formula (1). The resulting aqueous solution (Si) has a pH in the
range of from 8.0 to 9.0.
##STR00005##
Preparative Example 1a
[0071] An aqueous formulation (F1a) is prepared by slowly adding 2
parts of compound of formula (a) and 77 parts of water to 921 parts
of a preformed aqueous solution containing 0.216 mol per kg of
compound of formula (1) (synthesized according to example 1 in GB
1114021 with the sole difference that the final solution was
ultra-filtered to remove salts and concentrated to 0.216 mol per kg
of compound of formula (1)) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F1a)
containing compound of formula (a) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F1a) and 0.199 mol per kg of compound of
formula (1). The resulting aqueous formulation (F1a) has a pH in
the range of from 8.0 to 9.0.
##STR00006##
Preparative Example 1b
[0072] An aqueous formulation (F1b) is prepared by slowly adding 2
parts of compound of formula (b) and 77 parts of water to 921 parts
of a preformed aqueous solution containing 0.216 mol per kg of
compound of formula (1) (synthesized according to example 1 in GB
1114021 with the sole difference that the final solution was
ultra-filtered to remove salts and concentrated to 0.216 mol per kg
of compound of formula (1)) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F1b)
containing compound of formula (b) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F1b) and 0.199 mol per kg of compound of
formula (1). The resulting aqueous formulation (F1b) has a pH in
the range of from 8.0 to 9.0.
##STR00007##
Comparative Example 1c
[0073] An aqueous formulation (F1c) is prepared by slowly adding
18.2 parts of a preformed aqueous solution containing 11 weight %
of C.I. Direct Violet 35, the weight % being based on the total
weight of the aqueous C.I. Direct Violet 35 preformed solution and
60.8 parts of water to 921 parts of a preformed aqueous solution
containing 0.216 mol per kg of compound of formula (1) (synthesized
according to example 1 in GB 1114021 with the sole difference that
the final solution was ultra-filtered to remove salts and
concentrated to 0.216 mol per kg of compound of formula (1)) at
room temperature with efficient stirring. The obtained mixture is
stirred for 1 hour at room temperature to afford 1000 parts of an
aqueous formulation (F1 c) containing C.I. Direct Violet 35 at a
concentration of 0.2 weight %, the weight % being based on the
total weight of the final aqueous formulation (F1c) and 0.199 mol
per kg of compound of formula (1). The resulting aqueous
formulation (F1c) has a pH in the range of from 8.0 to 9.0.
Preparative Example 2
[0074] An aqueous solution (S2) is prepared by slowly adding 26
parts of water and 150 parts of urea to 824 parts of a preformed
aqueous mixture containing 0.250 mol per kg of compound of formula
(2), synthesized according to example 1 in EP 0884312-A1, at room
temperature with efficient stirring. The obtained mixture is
stirred for 1 hour at room temperature to afford 1000 parts of an
aqueous solution (S2) containing 0.206 mol per kg of compound of
formula (2). The resulting aqueous solution (S2) has a pH in the
range of from 8.0 to 9.0.
##STR00008##
Preparative Example 2a
[0075] An aqueous formulation (F2a) is prepared by slowly adding 2
parts of compound of formula (a), 150 parts of urea and 24 parts of
water to 824 parts of a preformed aqueous mixture containing 0.250
mol per kg of compound of formula (2) at room temperature with
efficient stirring. The obtained mixture is stirred for 1 hour at
room temperature to afford 1000 parts of an aqueous formulation
(F2a) containing compound of formula (a) at a concentration of 0.2
weight %, the weight % being based on the total weight of the final
aqueous formulation (F2a) and 0.206 mol per kg of compound of
formula (2). The resulting aqueous formulation (F2a) has a pH in
the range of from 8.0 to 9.0.
Preparative Example 2b
[0076] An aqueous formulation (F2b) is prepared by slowly adding 2
parts of compound of formula (b), 150 parts of urea and 24 parts of
water to 824 parts of a preformed aqueous mixture containing 0.250
mol per kg of compound of formula (2) at room temperature with
efficient stirring. The obtained mixture is stirred for 1 hour at
room temperature to afford 1000 parts of an aqueous formulation
(F2b) containing compound of formula (b) at a concentration of 0.2
weight %, the weight % being based on the total weight of the final
aqueous formulation (F2b) and 0.206 mol per kg of compound of
formula (2). The resulting aqueous formulation (F2b) has a pH in
the range of from 8.0 to 9.0.
Comparative Example 2c
[0077] An aqueous formulation (F2c) is prepared by slowly adding
18.2 parts of a preformed aqueous solution containing 11 weight %
of C.l. Direct Violet 35, the weight % being based on the total
weight of the aqueous C.I. Direct Violet 35 preformed solution, 150
parts of urea and 7.8 parts of water to 824 parts of a preformed
aqueous mixture containing 0.250 mol per kg of compound of formula
(2) at room temperature with efficient stirring. The obtained
mixture is stirred for 1 hour at room temperature to afford 1000
parts of an aqueous formulation (F2c) containing C.I. Direct Violet
35 at a concentration of 0.2 weight %, the weight % being based on
the total weight of the final aqueous formulation (F2c) and 0.206
mol per kg of compound of formula (2). The resulting aqueous
formulation (F2c) has a pH in the range of from 8.0 to 9.0.
Preparative Example 3
[0078] An aqueous solution (S3) is prepared by slowly adding 181
parts of water to 819 parts of a preformed aqueous mixture
containing 0.238 mol per kg of compound of formula (3), synthesized
according to example 1 in WO 2007/017336-A1, at room temperature
with efficient stirring. The obtained mixture is stirred for 1 hour
at room temperature to afford 1000 parts of an aqueous solution
(S3) containing 0.195 mol per kg of compound of formula (3). The
resulting aqueous solution (S3) has a pH in the range of from 8.0
to 9.0.
##STR00009##
Preparative Example 3a
[0079] An aqueous formulation (F3a) is prepared by slowly adding 2
parts of compound of formula (a) and 179 parts of water to 819
parts of a preformed aqueous mixture containing 0.238 mol per kg of
compound of formula (3) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F3a)
containing compound of formula (a) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F3a) and 0.195 mol per kg of compound of
formula (3). The resulting aqueous formulation (F3a) has a pH in
the range of from 8.0 to 9.0.
Preparative Example 3b
[0080] An aqueous formulation (F3b) is prepared by slowly adding 2
parts of compound of formula (b) and 179 parts of water to 819
parts of a preformed aqueous mixture containing 0.238 mol per kg of
compound of formula (3) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F3b)
containing compound of formula (b) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F3b) and 0.195 mol per kg of compound of
formula (3). The resulting aqueous formulation (F3b) has a pH in
the range of from 8.0 to 9.0.
Comparative Example 3c
[0081] An aqueous formulation (F3c) is prepared by slowly adding
18.2 parts of a preformed aqueous solution containing 11 weight %
of C.I. Direct Violet 35, the weight % being based on the total
weight of the aqueous C.I. Direct Violet 35 preformed solution and
162.8 parts of water to 819 parts of a preformed aqueous mixture
containing 0.238 mol per kg of compound of formula (3) at room
temperature with efficient stirring. The obtained mixture is
stirred for 1 hour at room temperature to afford 1000 parts of an
aqueous formulation (F3c) containing C.I. Direct Violet 35 at a
concentration of 0.2 weight %, the weight % being based on the
total weight of the final aqueous formulation (F3c) and 0.195 mol
per kg of compound of formula (3). The resulting aqueous
formulation (F3c) has a pH in the range of from 8.0 to 9.0.
Preparative Example 4
[0082] An aqueous solution (84) is prepared by slowly adding 157
parts of water to 843 parts of a preformed aqueous mixture
containing 0.210 mol per kg of compound of formula (4) (synthesized
according to example 1 in WO 2011/033064-A2 with the sole
difference that the final solution was ultra-filtered to remove
salts and concentrated to 0.210 mol per kg of compound of formula
(4)) at room temperature with efficient stirring. The obtained
mixture is stirred for 1 hour at room temperature to afford 1000
parts of an aqueous solution (S4) containing 0.177 mol per kg of
compound of formula (4). The resulting aqueous solution (S4) has a
pH in the range of from 8.0 to 9.0.
##STR00010##
Preparative Example 4a
[0083] An aqueous formulation (F4a) is prepared by slowly adding 2
parts of compound of formula (a) and 155 parts of water to 843
parts of a preformed aqueous mixture containing 0.210 mol per kg of
compound of formula (4) (synthesized according to example 1 in WO
2011/033064-A2 with the sole difference that the final solution was
ultra-filtered to remove salts and concentrated to 0.210 mol per kg
of compound of formula (4)) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F4a)
containing compound of formula (a) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F4a) and 0.177 mol per kg of compound of
formula (4). The resulting aqueous formulation (F4a) has a pH in
the range of from 8.0 to 9.0.
Preparative Example 4b
[0084] An aqueous formulation (F4b) is prepared by slowly adding 2
parts of compound of formula (b) and 155 parts of water to 843
parts of a preformed aqueous mixture containing 0.210 mol per kg of
compound of formula (4) (synthesized according to example 1 in WO
2011/033064-A2 with the sole difference that the final solution was
ultra-filtered to remove salts and concentrated to 0.210 mol per kg
of compound of formula (4)) at room temperature with efficient
stirring. The obtained mixture is stirred for 1 hour at room
temperature to afford 1000 parts of an aqueous formulation (F4b)
containing compound of formula (b) at a concentration of 0.2 weight
%, the weight % being based on the total weight of the final
aqueous formulation (F4b) and 0.177 mol per kg of compound of
formula (4). The resulting aqueous formulation (F4b) has a pH in
the range of from 8.0 to 9.0.
Comparative Example 4c
[0085] An aqueous formulation (F4c) is prepared by slowly adding
18.2 parts of a preformed aqueous solution containing 11 weight %
of C.I. Direct Violet 35, the weight % being based on the total
weight of the aqueous C.I. Direct Violet 35 preformed solution and
138.8 parts of water to 843 parts of a preformed aqueous mixture
containing 0.210 mol per kg of compound of formula (4) (synthesized
according to example 1 in WO 2011/033064-A2 with the sole
difference that the final solution was ultra-filtered to remove
salts and concentrated to 0.210 mol per kg of compound of formula
(4)) at room temperature with efficient stirring. The obtained
mixture is stirred for 1 hour at room temperature to afford 1000
parts of an aqueous formulation (F4c) containing C.I. Direct Violet
35 at a concentration of 0.2 weight %, the weight % being based on
the total weight of the final aqueous formulation (F4c) and 0.177
mol per kg of compound of formula (4). The resulting aqueous
formulation (F4c) has a pH in the range of from 8.0 to 9.0.
Application Example 1
[0086] The solution (S1) and the formulations (F1a), (F1b) and
(F1c) prepared according to preparative Example 1, 1a, 1b and
comparative example 1c respectively are added at a range of
concentrations from 0 to 2 weight %, the weight % being based on
the total weight of dry fibre to 200 parts of a 2.5% aqueous
suspension of a 50:50 mixture of bleached spruce sulphite cellulose
and bleached beech sulphite cellulose beaten to a Schopper Riegler
wetness of 20.degree. SR. The suspensions are stirred for 5
minutes, then diluted to 1000 parts. A paper sheet is then made by
drawing the suspension through a wire mesh. After being pressed and
dried, the paper is measured for whiteness and brightness on a
calibrated Minolta spectrophotometer.
[0087] Results are depicted in table 1a and 1b respectively and
clearly shows the significant improvement in whiteness while
avoiding the disadvantages characterized by the use of shading dyes
(loss of brightness).
TABLE-US-00001 TABLE 1a CIE Whiteness Solution (S1) Formulation
(F1a) Formulation (F1b) from preparative from preparative from
preparative Conc. % example 1 example 1a example 1b 0.0 64.1 64.1
64.1 0.4 109.7 114.9 113.5 0.8 119.6 124.2 123.9 1.2 124.2 131.3
129.5 1.6 126.8 134.1 133.1 2.0 125.7 136.6 135.5
TABLE-US-00002 TABLE 1b Brightness Formulation Formulation Solution
(S1) Formulation (F1a) (F1b) from (F1c) from Conc. from preparative
from preparative preparative comparative % example 1 example 1a
example 1b example 1c 0.0 84.4 84.4 84.4 84.4 0.4 100.3 101.3 101.0
98.5 0.8 104.6 104.4 104.7 99.7 1.2 107.0 106.8 106.9 100.3 1.6
108.5 107.8 107.8 99.5 2.0 108.6 108.3 108.9 98.8
Application Example 2
[0088] The solution (S2) and the formulations (F2a), (F2b) and
(F2c) prepared according to preparative Example 2, 2a, 2b and
comparative example 2c respectively are added at a range of
concentrations from 0 to 2 weight %, the weight % being based on
the total weight of dry fibre to 200 parts of a 2.5% aqueous
suspension of a 50:50 mixture of bleached spruce sulphite cellulose
and bleached beech sulphite cellulose beaten to a Schopper Riegler
wetness of 20.degree. SR. The suspensions are stirred for 5
minutes, then diluted to 1000 parts. A paper sheet is then made by
drawing the suspension through a wire mesh. After being pressed and
dried, the paper is measured for whiteness on a calibrated Minolta
spectrophotometer.
[0089] Results are depicted in table 2a and 2b respectively and
clearly shows the significant improvement in whiteness while
avoiding the disadvantages characterized by the use of shading dyes
(loss of brightness).
TABLE-US-00003 TABLE 2a CIE Whiteness Solution (S2) Formulation
(F2a) Formulation (F2b) from preparative from preparative from
preparative Conc. % example 2 example 2a example 2b 0.0 64.1 64.1
64.1 0.4 112.5 116.8 115.4 0.8 120.3 124.4 123.9 1.2 125.2 128.7
128.7 1.6 126.0 131.3 131.7 2.0 127.7 133.4 132.9
TABLE-US-00004 TABLE 2b Brightness Formulation Formulation Solution
(S2) Formulation (F2a) (F2b) from (F2c) from Conc. from preparative
from preparative preparative comparative % example 2 example 2a
example 2b example 2c 0.0 84.4 84.4 84.4 84.4 0.4 101.5 102.6 102.0
100.1 0.8 105.0 105.3 105.0 101.2 1.2 107.5 106.8 106.7 101.0 1.6
108.2 107.7 107.9 100.7 2.0 109.3 108.2 108.1 99.6
Application Example 3
[0090] The solution (S3) and the formulations (F3a), (F3b) and
(F3c) prepared according to preparative Example 3, 3a, 3b and
comparative example 3c respectively are added at a range of
concentrations from 0 to 2 weight %, the weight % being based on
the total weight of dry fibre to 200 parts of a 2.5% aqueous
suspension of a 50:50 mixture of bleached spruce sulphite cellulose
and bleached beech sulphite cellulose beaten to a Schopper Riegler
wetness of 20.degree. SR. The suspensions are stirred for 5
minutes, then diluted to 1000 parts. A paper sheet is then made by
drawing the suspension through a wire mesh. After being pressed and
dried, the paper is measured for whiteness on a calibrated Minolta
spectrophotometer.
[0091] Results are depicted in table 3a and 3b respectively and
clearly shows the significant improvement in whiteness while
avoiding the disadvantages characterized by the use of shading dyes
(loss of brightness).
TABLE-US-00005 TABLE 3a CIE Whiteness Solution (S3) Formulation
(F3a) Formulation (F3b) from preparative from preparative from
preparative Conc. % example 3 example 3a example 3b 0.0 64.1 64.1
64.1 0.4 112.3 116.4 116.1 0.8 119.7 126.6 125.6 1.2 123.9 132.0
130.7 1.6 126.1 135.1 134.2 2.0 126.1 138.4 135.3
TABLE-US-00006 TABLE 3b Brightness Formulation Formulation Solution
(S3) Formulation (F3a) (F3b) from (F3c) from Conc. from preparative
from preparative preparative comparative % example 3 example 3a
example 3b example 3c 0.0 84.4 84.4 84.4 84.4 0.4 101.4 101.9 102.0
99.4 0.8 104.7 105.6 105.1 100.0 1.2 106.9 107.3 106.9 100.5 1.6
108.4 108.1 107.9 99.3 2.0 108.7 108.8 107.8 98.3
Application Example 4
[0092] The solution (S4) and the formulations (F4a), (F4b) and
(F4c) prepared according to preparative Example 4, 4a, 4b and
comparative example 4c respectively are added at a range of
concentrations from 0 to 2 weight %, the weight % being based on
the total weight of dry fibre to 200 parts of a 2.5% aqueous
suspension of a 50:50 mixture of bleached spruce sulphite cellulose
and bleached beech sulphite cellulose beaten to a Schopper Riegler
wetness of 20.degree. SR. The suspensions are stirred for 5
minutes, then diluted to 1000 parts. A paper sheet is then made by
drawing the suspension through a wire mesh. After being pressed and
dried, the paper is measured for whiteness on a calibrated Minolta
spectrophotometer.
[0093] Results are depicted in table 4a and 4b respectively and
clearly shows the significant improvement in whiteness while
avoiding the disadvantages characterized by the use of shading dyes
(loss of brightness).
TABLE-US-00007 TABLE 4a CIE Whiteness Solution (S4) Formulation
(F4a) Formulation (F4b) from preparative from preparative from
preparative Conc. % example 4 example 4a example 4b 0.0 64.1 64.1
64.1 0.4 109.1 116.5 114.4 0.8 119.7 126.0 126.9 1.2 125.0 131.6
132.3 1.6 125.7 132.3 133.7 2.0 126.1 133.9 135.2
TABLE-US-00008 TABLE 4b Brightness Formulation Formulation Solution
(S4) Formulation (F4a) (F4b) from (F4c) from Conc. from preparative
from preparative preparative comparative % example 4 example 4a
example 4b example 4c 0.0 85.5 85.5 85.5 85.5 0.4 99.9 101.9 100.8
99.5 0.8 104.5 105.1 105.5 100.9 1.2 107.8 107.1 107.4 100.5 1.6
108.6 107.3 107.8 99.5 2.0 109.1 107.5 108.2 99.1
* * * * *