Process for obtaining coating compositions of improved whiteness

A process is disclosed for obtaining coating compositions of improved whiteness for coating paper or cardboard using fluorescent whitening agents of the bis-triazinylaminostilbene-2,2'-disulfonic acid series, which process comprises adding to the coating compositions, in addition to the respective fluorescent whitening agent, an acid phosphoric acid ester of an oxyalkylated fatty amine of the formula ##STR1## or an alkali metal salt, ammonium salt or amine salt thereof, wherein R is an aliphatic hydrocarbon radical of 8 to 22 carbon atoms, Y.sub.1 and Y.sub.2 are both hydrogen, or one of Y.sub.1 and Y.sub.2 is hydrogen and the other is methyl, X is the acid radical of phosphoric acid, the acid hydrogen atoms of which radical can be replaced by alkali metal ions, ammonium ions or amine salt ions, and m and n are integers, the sum of which is 2 to 30. To the coating compositions can also be added organic solubilizers, non-ionic or anionic surfactants and/or polar organic compounds. Coating compositions which contain the above fluorescent whitening agents and assistants are also disclosed.

The present invention relates to a process for obtaining coating 
compositions of improved whiteness for coating paper or cardboard using 
fluorescent whitening agents of the 
bis-triazinylaminostilbene-2,2'-disulfonic acid series, to whitened 
coating compositions and to the paper or cardboard coated therewith. 
It is known that fluorescent whitening agents of the class of 
bis-triazinylaminostilbene-2,2'-disulfonic acids are suitable for 
whitening paper. When whitening coating compositions, however, problems 
arise depending on the fluorescent whitening agent employed and on the 
composition of the coating composition, so that either the white effects 
obtained are unsatisfactory or many fluorescent whitening agents are quite 
unsuitable for application in certain coating compositions. When high 
concentrations of fluorescent whitening agent are used there often occurs 
a sharp decrease, instead of an increase, in the degree of whiteness, and 
the coating composition often also takes on a greenish hue. This 
undesirable effect occurs in particular when many of the above mentioned 
fluorescent whitening agents are added to coating compositions which 
contain synthetic binders. 
Efforts have already been made to overcome these difficulties. For example, 
solubilisers, especially polyethylene glycol, have been added to the 
coating composition. When using many fluorescent whitening agents, this 
measure results in a certain increase in the white effect, but, when using 
others, it fails. Moreover, any increase in the white effect obtained is 
often unsatisfactory. 
Other solutions proposed have been the addition of surfactants (cf. British 
patent specification No. 1 294 173), or of amide-formaldehyde resins (cf. 
German Offenlegungsschrift No. 2 229 872), to the coating compositions. 
Although white effects are obtained, they do not meet the desired 
requirements as regards the degree of whiteness. In any case, these 
measures are only applicable to coating compositions which contain 
synthetic binders, but not to technically important mixtures of natural 
and synthetic binders. 
German Offenlegungsschrift Nos. 2 806 194 and 2 806 195 disclose coating 
compositions to which is added a disperse fluorescent whitening agent or a 
bis-triazinylaminostilbene-2,2'-disulfonic acid fluorescent whitening 
agent in admixture with water, an organic liquid which boils above 
150.degree. C., e.g. triethylphosphate, trioctylphosphate, 
tricresylphosphate or trichloroethylphosphate, and a solubiliser, e.g. a 
non-ionic emulsifier. This method is suitable primarily for disperse 
fluorescent whitening agents. Moreover, the use of relatively expensive 
high-boiling organic solvents is not advantageous for a variety of 
reasons. 
Accordingly, it is the object of the present invention to provide a process 
that does not have the drawbacks referred to above, that results in better 
white effects especially when using 
bis-triazinylaminostilbene-2,2'-disulfonic acid fluorescent whitening 
agents in coating compositions, that eliminates the greenish hue occuring 
in coating compositions when using higher concentrations of fluorescent 
whitening agent, and that makes it possible to use many fluorescent 
whitening agents of the above class which up to now were not considered 
suitable for this application. 
Surprisingly, it has been possible to attain this object by adding to the 
coating composition, besides the fluorescent whitening agent, an acid 
phosphoric acid ester of an oxyalkylated fatty amine of the formula (1) 
below. This measure results in a substantial improvement in the degree of 
whiteness of the whitened coating composition, especially when using 
higher concentrations of fluorescent whitening agent, and the undesirable 
greenish discolouration of the coating composition is avoided. In contrast 
to the conventional whitening of coating compositions with 
bis-triazinylaminostilbene-2,2'-disulfonic acid fluorescent whitening 
agents, the degree of whiteness increases almost linearly with the 
logarithm of the increasing concentration of fluorescent whitening agent, 
so that very high degrees of whiteness can be obtained. 
Accordingly, the process for obtaining coating compositions of improved 
whiteness for coating paper or cardboard using fluorescent whitening 
agents of the bis-triazinylaminostilbene-2,2'-disulfonic acid series 
comprises adding to the coating compositions, in addition to the 
respective fluorescent whitening agent, an acid phosphoric acid ester of 
an oxyalkylated fatty amine of the formula 
##STR2## 
or an alkali metal salt, ammonium salt or amine salt thereof, wherein R is 
an aliphatic hydrocarbon radical of 8 to 22 carbon atoms, Y.sub.1 and 
Y.sub.2 are both hydrogen, or one of Y.sub.1 and Y.sub.2 is hydrogen and 
the other is methyl, X is the acid radical of phosphoric acid, the acid 
hydrogen atoms of which radical can be replaced by alkali metal ions, 
ammonium ions or amine salt ions, and m and n are integers, the sum of 
which is 2 to 30. 
In the assistants of the formula (1) employed in the process of this 
invention, the aliphatic radical R is preferably an alkyl or alkenyl 
radical (branched or unbranched) of 10 to 18 carbon atoms. Preferred 
assistants have the formula 
##STR3## 
wherein R' is an alkyl or alkenyl radical of 10 to 18 carbon atoms, X' is 
the acid radical of phosphoric acid, the acid hydrogen atoms of which 
radical can also be replaced by alkali metal ions or ammonium ions, and n' 
and m' are integers, the sum of which is 4 to 20. 
Especially preferred compounds of the formula (2) employed in the process 
of the invention are those in which the sum of n'+m' is 6 to 8, most 
preferably those in which R' is the lauryl radical, in which case the sum 
of n'+m' is most preferably 8. 
The radical R generally does not have to contain a specific number of 
carbon atoms, but can also be a mixture of hydrocarbon chains of different 
length such as many fatty amines which are derived from natural fats have. 
A preferred radical of this kind is the hydrocarbon radical of tallow 
fatty amine. The preferred meaning of Y.sub.1 and Y.sub.2 in formula (1) 
is hydrogen. 
The acid component of the ester of formula (1) is phosphoric acid. X is 
therefore the radical of phosphoric acid, whilst the terminal OH groups of 
the ethylene oxide or propylene oxide chains can be completely or only 
partially esterified. The number of acid hydrogen atoms in the phosphoric 
acid radical X is contingent on the degree of esterification, which need 
not be a whole number. These acid hydrogen atoms can also be replaced by 
alkali metal ions, ammonium ions or amine salt ions, so that the radical X 
is in salt form. However, it is preferred that the radical X is in its 
acid form. 
Depending on the degree of esterification, possible structures of compounds 
of the formula (1) are for example (Y.sub.1 and Y.sub.2 =H): 
##STR4## 
and the like. 
Bis-triazinylaminostilbene-2,2'-disulfonic acid fluorescent whitening 
agents which can be used for whitening coating compositions in the process 
of this invention are, in particular, those of the formula 
##STR5## 
wherein M is hydrogen, or an alkali metal ion, ammonium ion or amine salt 
ion, and R.sub.1 and R.sub.2 are NH.sub.2, NH--CH.sub.3, NH--C.sub.2 
H.sub.5, N(CH.sub.3).sub.2, N(C.sub.2 H.sub.5).sub.2, NH--CH.sub.2 
--CH.sub.2 --OH, NH--CH.sub.2 --CH.sub.2 --CH.sub.2 --OH, N(CH.sub.2 
--CH.sub.2 --OH).sub.2, N(CH.sub.2 --CH.sub.2 --CH.sub.2 --OH).sub.2, 
N(CH.sub.3)(CH.sub.2 --CH.sub.2 --OH), NH--CH.sub.2 --CH.sub.2 
--O--CH.sub.2 --CH.sub.2 --OH, NH--CH.sub.2 --CH.sub.2 --SO.sub.3 M, OH, 
OCH.sub.3, OCH(CH.sub.3).sub.2, O--CH.sub.2 --CH.sub.2 --O--CH.sub.3, 
##STR6## 
It is preferred to use a fluorescent whitening agent of the formula 
##STR7## 
wherein R.sub.1 ' is --NHCH.sub.2 CH.sub.2 OH, --N(CH.sub.2 CH.sub.2 
OH).sub.2, --N(CH.sub.2 CH.sub.3).sub.2 or 
##STR8## 
R.sub.2 ' is 
##STR9## 
and M' is hydrogen or an alkali metal ion, an ammonium, diethanolammonium 
or triethanolammonium ion. 
The sulfo groups --SO.sub.3 M in compounds of the formula (3) can be in the 
free form (M=H) or in salt form. M is then an alkali metal ion, especially 
a sodium or potassium ion, an ammonium ion or an amine salt ion, e.g. of a 
primary or secondary alkylamine, the alkyl group or groups of which can be 
substituted by halogen, hydroxyl (e.g. ethanolamine, diethanolamine, 
triethanolamine) or alkoxy, or of a cyclic amine, e.g. a piperidine, 
pyrrolidine, piperazine or morpholine. 
The acid hydrogen atoms in the phosphoric acid radical X of the compounds 
of the formula (1) or (2) can, if desired, be replaced by the same ions as 
defined above for M. The radical X is then in salt form. 
In addition to fluorescent whitening agent and assistant of the formula 
(1), it can often be advantageous to add to the coating composition other 
substances which either have a booster action or which favourably 
influence the properties of the coating composition. Suitable additional 
assistants of this kind are non-ionic or anionic surfactants, organic 
solubilisers or certain polar organic compounds or mixtures thereof. 
Examples of organic solubilisers and polar organic compounds which can be 
used are: lower monohydric alcohols, polyhydric alcohols, ether alcohols, 
not too high molecular weight polyglycols or carboxamies. Examples of such 
solvents are: propanol, isopropanol, ethylene glycol, propylene glycol, 
butylene glycol, glycerol, ethylene glycol monomethyl, monoethyl, 
monopropyl or monobutyl ether, dipropylene glycol, formamide, dimetyl 
formamide, dimethyl acetamide and N-methylpyrrolidone. Preferred solvents 
of this kind are ethylene glycol and N-methylpyrrolidone. Further suitable 
solubilisers and solvents are amines such as triethanolamines and other 
water-soluble polar compounds such as dimethyl sulfoxide, dimethyl 
methanephosphonate, dimethyl sulfone, sulfolane 
(tetrahydrothiophene-1,1-dioxide), ethylene carbonate or propylene 
carbonate, and also urea or substituted ureas, e.g. tetramethylurea. 
Examples of non-ionic surfactants which can be used are: adducts of 
alkylene oxides, especially of ethylene oxide, with higher fatty acids, 
fatty acid amides, aliphatic alcohols, mercaptans or amines, with 
alkylphenols or alkylthiophenols containing at least 7 carbon atoms in the 
alkyl moieties, or with phenylphenols, e.g. polyglycol-(monoalkylphenyl) 
ethers containing at least 8 to 12 carbon atoms in the alkyl moiety and at 
least 8 unsubstituted or substituted glycol units, e.g. decaethylene 
glycol monooctoylphenyl ether or the reaction product of monononylphenol 
with 5 to 35 moles of ethylene oxide; copolymers of ethylene oxide and 
higher alkylene oxides, e.g. propylene oxide or butylene oxide; non-ionic 
esters of adducts of alkylene oxides, e.g. the tertiary phosphoric acid 
ester of the adduct of 40 moles of ethylene oxide and monononylphenol; 
esters of polyalcohols, especially monoglycerides of fatty acids 
containing 12 to 18 carbon atoms, e.g. the monoglycerides of lauric, 
stearic or oleic acid; N-acylated alkanolamines of the same type as 
mentioned for the sulfates of these compounds (see below), e.g. the 
N,N-bis-(.omega.-hydroxyalkyl)amides of the mixtures of acids collectively 
known as coconut oil fatty acids, in particular 
N,N-bis-(.beta.-hydroxyethyl)amide or 
N,N-bis-(.gamma.-hydroxypropyl)amide, and also the adducts of ethylene 
oxide with these N-acylated alkanolamines; reaction products of higher 
fatty acids with an alkanolamine, the molar ratio of alkanolamine to fatty 
acid being greater than 1, e.g. 2. Suitable fatty acids are, in 
particular, those containing 8 to 18 carbon atoms, as well as the mixtures 
known as coconut oil fatty acids. A suitable alkanolamine is, in 
particular, diethanolamine. 
Examples of suitable anionic surfactants which can be used are: sulfated 
alkylene oxide adducts, especially sulfated ethylene oxide adducts, such 
as sulfated adducts of 1 to 40 moles of ethylene oxide with fatty acid 
amides, mercaptans or amines, but in particular with fatty acids, 
aliphatic alcohols or alkylphenols containing 8 to 20 carbon atoms in the 
alkyl chain, e.g. with stearic acid, oleic acid, lauryl alcohol, myristyl 
alcohol, stearyl alcohol, oleyl alcohol, octyl phenol or nonylphenol. 
Instead of the sulfates, it is also possible to use the esters of other 
polyvalent acids. Such esters comprise e.g. the primary and secondary 
esters of phosphoric acid as well as the hemiesters of sulfosuccinic acid; 
sulfates of N-acylated alkanolamines, e.g. the sulfated amides of caprylic 
acid, pelargonic acid, capric acid, lauric acid, myristic or stearic acid, 
or of lower fatty acids substituted by alkylphenoxy groups, e.g. octyl- or 
nonylphenoxyacetic acid, with mono- or bis-hydroxyalkylamines such as 
.beta.-hydroxyethylamine, .gamma.-hydroxypropylamine, 
.beta.,.gamma.-dihydroxypropylamine, bis-(.beta.-hydroxyethyl)amine, or 
with N-alkyl-N-hydroxyalkylamines such as N-methyl- or 
N-ethyl-N-(.beta.-hydroxyethyl)amine; and sulfated esterified polyoxy 
compounds, e.g. sulfated, partially esterified polyhydric alcohols, such 
as the sodium salt of the sulfated monoglyceride of palmitic acid. 
The acid phosphoric acid esters of oxyalkylated fatty amines of the formula 
(1) employed in the process of this invention are known and can be easily 
obtained by esterification of an oxyalkylated fatty amine of the formula 
##STR10## 
wherein the general symbols are as defined for formula (1), with 
phosphoric acid, phosphorus pentoxide or a halide of phosphoric acid. The 
reaction with phosphorus pentoxide is preferred. The esterification is 
conveniently carried out by a simple mixing of the reactants with 
simultaneous heating, e.g. to 50.degree.-100.degree. C. If desired, the 
acid esters can be converted into the corresponding salts (alkali metal, 
ammonium or amine salts), e.g. in conventional manner by addition of the 
appropriate base, e.g. ammonia, monoethanolamine, triethanolamine or an 
alkali metal hydroxide. 
The compound of the formula 
##STR11## 
wherein the sum of n"+m" is 8 and X is an acid phosphoric acid radical, 
can be obtained as follows: 914.6 g of the compound of the formula 
##STR12## 
are put at room temerature into a flask and, with stirring, cooled to 
18.degree. C. with a water/ice bath. Then 80.94 g of phosphorus pentoxide 
are added rapidly. The cooling bath is removed, whereupon the temperature 
of the yellowish suspension rises to room temperature. The suspension is 
then heated with an oil bath to 40.degree. C. in the course of 2 hours and 
to 60.degree. C. in the course of a further 2 hours. The batch is then 
stirred for 1 hour at 60.degree. C. The resultant product is a yellow, 
readily pourable gel. The analogous compounds of the formulae (6a), (6b), 
(6c) and (6d) (see the Examples) are also obtained by the above procedure. 
The adducts of the formula (5) are known and can be obtained in known 
manner by addition of 2 to 30 moles of ethylene oxide or propylene oxide 
to an aliphatic amine containing a hydrocarbon radical of 8 to 22 carbon 
atoms. 
The process of the invention is conveniently carried out by adding e.g. to 
the respective coating liquor, which is prepared in conventional manner, 
the fluorescent whitening agent, an acid phosphoric acid ester of an 
oxyalkylated fatty amine of the formula (1) and, if desired, one or more 
of the additional assistants referred to above, singly and in any order, 
and dispersing them therein, for example in the temperature range from 
10.degree. to 150.degree. C. Alternatively, the fluorescent whitening 
agent can also be mixed, before the addition to the coating liquor, with 
an acid phosphoric acid ester of an oxyalkylated fatty amine of the 
formula (1) and, if desired, with one or more of the additional assistants 
referred to above, advantageously with the addition of water, and the 
preparation so obtained can then be added, as described above, to the 
coating liquor. Paper or cardboard can then be coated with the 
ready-for-use coating composition, for example with an air-knife, a 
coating knife, a brush, a roller or doctor knife, a bar or another coating 
means customarily employed in the paper industry. 
The amount of compound of the formula (1) employed in the process of this 
invention can vary within wide limits. Positive effects are observed even 
at a low ratio of fluorescent whitening agent to compound of the formula 
(1) of 1:0.5. This ratio is preferably 1:1, most preferably 1:1 to 1:3. 
Especially good effects are obtained using a ratio of 1:2. It would be 
entirely possible to use more compound of the formula (1) than corresponds 
to the ratio 1:5; however, this is not desirable both for economic reasons 
and on account of the effect on the consistency of the coating composition 
in actual practice. The amount of optional assistants (surfactants, 
solubilisers, polar compounds) can vary within wide limits. The ratio of 
fluorescent whitening agent to these assistants can be from 1:0.1 to 1:10, 
depending on the nature of the assistant employed (see also the Examples). 
The amount of fluorescent whitening agent added to the coating composition 
fluctuates within the limits customary in the paper industry. Suitable 
amounts are e.g. from 1 to 50 g/l of coating composition, preferably from 
4 to 20 g/l. As already mentioned, the invention also allows the use of 
higher concentrations of fluorescent whitening agent than normally 
employed (e.g. 4 to 8 g/l). Without the addition of compounds of the 
formula (1), a diminution in the degree of whiteness frequently occurs at 
concentrations of more than 10 g/l of fluorescent whitening agent, i.e. 
the coating composition takes on a greenish hue. But the addition of 
compounds of the formula (1) to the coating composition eliminates this 
effect and the degree of whiteness also increases with increasing 
concentration of fluorescent whitening agent. 
The process of the invention is suitable for whitening coating compositions 
normally employed in the paper industry, viz. unpigmented, but especially 
pigmented, coating compositions. These coating compositions contain a 
polymer binder, an inorganic pigment (in the case of pigmented 
compositions) and, if desired, further ingredients, e.g. waxes, 
dispersants, wetting agents or other surface-active compounds, viscosity 
regulators, antifoams, lubricants, plasticisers and/or preservatives. 
Suitable polymer binders are the polymer adhesive-binder systems commonly 
employed in the paper industry. For example, it is possible to use any of 
the known modified or converted starches such as oxidised, hydrolysed or 
hydroxyethylated starches. In addition to the different varieties and 
types of starch, it is possible to use other natural or synthetic polymer 
binder systems by themselves or, especially in the case of synthetic 
polymer binder systems, in combination with one another. Dispersions based 
on copolymers of butadiene/styrene, acrylonitrile/butadiene/styrene, 
acrylates, ethylene/vinyl chloride and ethylene/vinyl acetate, or based on 
homopolymers such as polyvinyl chloride, polyvinylidene chloride, 
polyethylene, polyvinyl pyrrolidone, polyvinyl alcohol and polyvinyl 
acetate, as well as polyurethanes, are suitable binders for the coating 
compositions to be whitened in the process of this invention. Degraded 
starches, alginates, carboxymethyl cellulose, proteins (e.g. gelatin, 
casein, soya protein) can also be used as binders. 
As white pigments it is possible to use e.g. aluminium-magnesium silicates 
(China clay), calcium carbonate, CaSO.sub.4.1OH.sub.2 O (satin white), 
aluminium silicates and aluminium hydroxides, barium sulfate (barite), or 
titanium dioxide or mixtures of such pigments. In addition, sequestering 
agents can be added to the coating compositions to eliminate undesired 
traces of metal [e.g. Fe(III)], for example water-soluble poly- or 
metaphosphates and polycarboxylic acid salts. 
To obtain good flow properties, an alkaline coating liquor is used for 
pigment coating. The alkaline reaction is conveniently effected with 
ammonia or NaOH or KOH or with sodium or potassium carbonates or borates 
or mixtures thereof. 
Examples of suitable wetting agents are adducts of unsulfated or sulfated 
higher alkanol or alkylphenol polyglycol ethers containing 8 to 14 carbon 
atoms in the alkyl moiety with 1 to 20 moles of ethylene oxide. 
Recipes for such known coating compositions to be whitened by the process 
of the invention are described e.g. in J. P. Casey, "Pulp and Paper"; 
Chemistry and Chemical Technology, 2nd Edition, Vol. III, pp. 1648-1649, 
and in McGraw-Hill, "Pulp and Paper Manufacture", 2nd Edition, Vol. II, p. 
497. 
The present invention also relates to the coating compositions whitened by 
the process of the invention, i.e. compositions containing a fluorescent 
whitening agent of the bis-triazinylaminostilbene-2,2'-disulfonic acid 
series, preferably a compound of the formula (3), especially one of the 
formula (4), and an acid phosphoric acid ester of an oxyalkylated fatty 
amine of the formula (1), preferably one of the formula (2). 
Further, in addition to containing the fluorescent whitening agent and the 
acid phosphoric acid ester of an oxyalkylated fatty amine, the coating 
compositions of this invention can also contain non-ionic or anionic 
surfactants, organic solubilisers and/or polar organic compounds, e.g. as 
organic solubilisers, hydrophilic organic solvents, for example lower 
monohydric alcohols, polyhydric alcohols, ether alcohols, glycols, 
polyglycols, glycol ethers and polyglycol ethers, amides and/or amines or, 
as polar organic compounds, dimethyl sulfoxide, dimethyl sulfone, ethylene 
carbonate or propylene carbonate and/or urea, or non-ionic surfactants 
such as adducts of alkylene oxides with higher fatty acids, fatty acid 
amides, aliphatic alcohols, mercaptans or amines, with alkylphenols, 
alkylthiophenols or phenylphenols, copolymers of ethylene oxides and 
higher alkylene oxides, non-ionic esters of adducts of alkylene oxides, 
esters of polyalcohols, N-acylated alkanolamines and the adducts thereof 
with ethylene oxide and reaction products of higher fatty acids with an 
alkanolamine and/or, as surfactants, alkylene oxide adducts containing 
sulfate or other acid radicals, sulfates of N-acylated alkanolamines and 
sulfated esterified polyoxy compounds. 
Finally, the present invention also relates to paper and cardboard coated 
with the coating compositions (as described above) of this invention.

The invention is described by the following Examples, in which parts and 
percentages are by weight, unless otherwise indicated. 
EXAMPLES 1 
(a) With stirring, 100 g of starch ("Paperol R 10") and 950 ml of 
demineralised water are heated in a 2 liter glass beaker to 80.degree. C. 
in the course of 10 to 15 minutes, and then stirred for 15 minutes at 
80.degree.-85.degree. C. A slightly turbid, grey, colloidal solution is 
obtained. The mixture is then cooled to about 40.degree. C. and 50 ml of 
4-nonylphenol oxyethylated with 9.7 moles of ethylene oxide (solution 
1:25) are added. After it has been bulked with demineralised water of 
40.degree. C. to 1000 ml, the mixture is briefly shaken and the pH is 
adjusted to 8-9 with concentrated ammonia. 
(b) To 15 ml of the starch liquor obtained in (a) are added 5 ml of a 
solution which consists of 11.6 g of the fluorescent whitening agent of 
the formula 
##STR13## 
20 g of the acid phosphoric acid ester of an oxyalkylated fatty amine of 
the formula (6), 10 g of a 4-nonylphenol oxyethylated with 9.7 moles of 
ethylene oxide, 15 g of ethylene glycol, 18 g of polyethylene glycol 300, 
and 25.4 g of water. The resultant mixture is homogenised with a magnetic 
stirrer. 
(c) After about 20 minutes the coating composition obtained in (b) is 
stirred again and prepared strips of coating paper are coated therewith in 
conventional manner. The degree of whiteness obtained on the paper so 
coated is distinctly higher than that obtained on a comparison strip of 
paper which is coated with a coating composition which does not contain 
the compound of the formula (6). 
EXAMPLE 2 
(a) With stirring, 100 g of starch ("Paperol R 10") and 950 ml of 
demineralised water are heated in a 2 liter glass beaker to 80.degree. C. 
in the course of 10 to 15 minutes, and then stirred for 15 minutes at 
80.degree.-85.degree. C. A slightly turbid, grey, colloidal solution is 
obtained to which are added 7.5 g of the acid phosphoric acid ester of an 
oxyalkylated fatty amine of the formula (6). The mixture is then cooled to 
about 40.degree. C. and 50 ml of 4-nonylphenol oxyethylated with 9.7 moles 
of ethylene oxide (solution 1:25) are added. After it has been bulked with 
demineralised water of 40.degree. C. to 1000 ml, the mixture is briefly 
shaken and the pH is adjusted to 8-9 with concentrated ammonia. 
(b) To 15 ml of the starch liquor obtained in (a) are added 5 ml of a 
solution of 11.6 g of the fluorescent whitening agent of the formula (10) 
in 88.4 g of water. The resultant mixture is homogenised with a magnetic 
stirrer. 
(c) After about 20 minutes the coating composition obtained in (b) is 
stirred again and prepared strips of coating paper are coated therewith in 
conventional manner. The degree of whiteness obtained on the paper so 
coated is distinctly higher than that obtained on a comparison strip of 
paper which is coated with a coating composition which does not contain 
the compound of the formula (6). 
EXAMPLE 3 
The procedure of Example 1 is repeated using, instead of the fluorescent 
whitening agent of the formula (10), the corresponding amount of a 
fluorescent whitening agent of each the following formulae: 
##STR14## 
Paper having a similarly high degree of whiteness is obtained. 
EXAMPLE 4 
The procedure of Example 2 is repeated using, instead of the fluorescent 
whitening agent of the formula (10), the corresponding amount of a 
fluorescent whitening agent of the formulae (11), (12), (13), (14) or 
(15). Paper having a similarly high degree of whiteness is obtained. 
EXAMPLE 5 
To 15 ml of a starch liquor obtained in accordance with Example 1(a) are 
added 5 ml of each of the following solutions: 
(A) 
20 g of the compound of formula (6), 
11.6 g of the fluorescent whitening agent of the formula (10), 
15 g of ethylene glycol, 
53.4 g of water; 
(B) 
10 g of the compound of formula (6), 
5.8 g of the fluorescent whitening agent of the formula (10), 
9 g of polyethylene glycol 300, 
25.2 g of water; 
(C) 
10 g of the compound of formula (6), 
5.8 g of the fluorescent whitening agent of the formula (10), 
5 g of a 4-nonylphenol oxyethylated with 9.7 moles of ethylene oxide, 
29.2 g of water; 
(D) 
10 g of the compound of formula (6), 
5.8 g of the fluorescent whitening agent of the formula (10), 
5 g of a 4-nonylphenol oxyethylated with 9.7 moles of ethylene oxide, 
21.7 g of water; 
(E) 
10 g of the compound of formula (6), 
5.8 g of the fluorescent whitening agent of the formula (10), 
7.5 g of ethylene glycol, 
9 g of polyethylene glycol 300, 
17.7 g of water. 
The preparation of the respective coating composition and the coating of 
the paper are as described in Example 1(b) and 1(c). In each case, the 
paper has a degree of whiteness distinctly higher than that obtained on 
paper coated with a coating composition containing the individual 
formulations (A) to (E), but without the compound of formula (6). 
Paper having a similarly high degree of whiteness is obtained by 
substituting a fluorescent whitening agent of the formula (11), (12), 
(13), (14) or (15) for that of the formula (10). 
The individual components of solutions (A) to (E) can also be added singly 
and in any order to the coating composition, in which case similar results 
are obtained. 
EXAMPLE 6 
To 15 ml of a starch liquor obtained in accordance with Example 1(a) are 
added 5 ml of each of the following solutions: 
(A) 
30 g of the compound of formula (6), 
16.7 g of the fluorescent whitening agent of the formula 
##STR15## 
53.3 g of water; 
(B) 
30 g of the compound of formula (6), 
16.7 g of the fluorescent whitening agent of the formula (10a), 
9 g of urea, 
44.3 g of water; 
(C) 
30 g of the compound of formula (6), 
16.9 g of the fluorescent whitening agent of the formula 
##STR16## 
53.1 g of water; 
(D) 
30 g of the compound of the formula 
##STR17## 
wherein the sum of n'"+m'" is 12 and X is as defined for formula (6), 
16.9 g of the fluorescent whitening agent of the formula (10b), 
53.1 g of water; 
(E) 
30 g of the compound of the formula 
##STR18## 
wherein the sum of n.sup.1v +m.sup.1v is 20 and X is as defined for 
formula (6), 
16.9 g of the fluorescent whitening agent of the formula (10b), 
53.1 g of water; 
(F) 
30 g of the compound of the formula 
##STR19## 
wherein the sum of n"+m" is 8, X is as defined for formula (6) and 
R.sub.1 is the hydrocarbon radical of tallow fatty amine, 
16.9 g of the fluorescent whitening agent of the formula (10b), 
53.1 g of water. 
The preparation of the coating composition and the coating of the paper are 
as described in Example 1(b) and 1(c). In each case, the paper has a 
degree of whiteness distinctly higher than that obtained on paper coated 
with a coating composition containing the individual formulations (A) to 
(F), but without the compound of the formula (6), (6a), (6b) or (6c). 
Paper having a similarly high degree of whiteness is obtained by 
substituting corresponding amounts of a fluorescent whitening agent of the 
formula (11), (12), (13), (14) or (15) for that of the formula (10a) or 
(10b) in the solutions (A) to (F). 
The individual components of solutions (A) to (F) can also be added singly 
and in any order to the coating compositions, in which case similar 
results are obtained. 
EXAMPLE 7 
(A) To 15 ml of a starch liquor obtained in accordance with Example 1(a) 
are added 1.1 g of the fluorescent whitening agent of the formula (15), 
0.85 g of the acid ester of the formula (6) and 3 g of water. The 
resultant mixture is homogenised with a magnetic stirrer. 
(B) To 15 ml of a starch liquor obtained in accordance with Example 1(a) 
are added 1.1 g of the fluorescent whitening agent of the formula (15), 
0.51 g of the acid ester of the formula (6c), and 3.4 g of water. The 
resultant mixture is homogenised with a magnetic stirrer. 
(C) Procedure (B) is repeated, substituting the same amount of an ester of 
the formula (6a) for the acid ester of the formula (6c). 
(D) Procedure (B) is repeated, substituting the same amount of an ester of 
the formula (6b) for the acid ester of formula (6c). 
After about 20 minutes the coating compositions (A) to (D) are stirred once 
more and prepared strips of coating paper are coated therewith in 
conventional manner. The degree of whiteness obtained on the paper strips 
is in each case distinctly higher than that obtained on comparison strips 
coated with compositions which do not contain the acid ester of the 
formula (6), (6a), (6b) or (6c). 
EXAMPLE 8 
(a) With stirring, 150 ml of an aqueous dispersion of a copolymer of 
acrylate and styrene (free from plasticisers and solvent), 100 ml of the 
sodium salt of a polycarboxylic acid (solution 1:50), 500 ml of China clay 
Dinkie A, and 50 ml of a 4-nonylphenol oxyethylated with 9.7 moles of 
ethylene oxide (solution 1:25) are added to 600 ml of water. The mixture 
is stirred until a homogeneous coating liquor is obtained. This pigmented 
coating liquor is deaerated and freed from coarser impurities by sieving 
it through a nickel sieve. 
(b) To 15 ml of the pigmented coating liquor obtained in (a) are added 5 ml 
of a solution consisting of 11.6 g of the fluorescent whitening agent of 
the formula (10), 20 g of the acid phosphoric acid ester of an 
oxyalkylated fatty amine of the formula (6), 10 g of a 4-nonylphenol 
oxyethylated with 9.7 moles of ethylene oxide, 15 g of ethylene glycol, 18 
g of polyethylene glycol 300, and 25.4 g of water. The resultant mixture 
is homogenised with a magnetic stirrer. 
(c) After about 20 minutes, the coating composition obtained in (b) is 
stirred once more and prepared strips of coating paper are coated 
therewith in conventional manner. The degree of whiteness obtained on the 
paper so coated is distinctly higher than that obtained on comparison 
paper which is coated with a coating composition that does not contain the 
compound of formula (6). 
EXAMPLE 9 
(a) With stirring, 14 g of the compound of formula (6), 150 ml of an 
aqueous dispersion of a copolymer of acrylate and styrene (free from 
plasticisers and solvent), 100 g of the sodium salt of a polycarboxylic 
acid (solution, 1:50), 500 ml of China clay Dinkie A, and 50 ml of a 
4-nonylphenol oxyethylated with 9.7 moles of ethylene oxide (solution 
1:25), are added to 600 ml of water. The mixture is stirred until 
homogeneous. This pigmented coating liquor is then deaerated and freed 
from coarser impurities by sieving it through a nickel sieve. 
(b) To 15 ml of the pigmented coating liquor obtained in (a) are added 5 ml 
of a solution consisting of 11.6 g of the fluorescent whitening agent of 
the formula (10) in 88.4 g of water. The resultant mixture is homogenised 
with a magnetic stirrer. 
(c) After about 20 minutes, the coating composition obtained in (b) is 
stirred once more and prepared strips of coating paper are coated 
therewith in conventional manner. The degree of whiteness obtained on the 
paper so coated is distinctly higher than that obtained on comparison 
paper which is coated with a coating composition that does not contain the 
compound of formula (6). 
EXAMPLE 10 
The procedure of Example 8 is repeated, substituting the corresponding 
amount of a fluorescent whitening agent of the formula (11), (12), (13), 
(14) or (15) for that of the formula (10). Paper having a similarly high 
degree of whiteness is obtained. 
EXAMPLE 11 
The procedure of Example 9 is repeated, substituting the corresponding 
amount of a fluorescent whitening agent of the formula (11), (12), (13), 
(14) or (15) for that of the formula (10). Paper having a similarly high 
degree of whiteness is obtained. 
EXAMPLE 12 
To 15 ml of a pigmented coating liquor obtained in accordance with Example 
8(a) are added 5 ml of each of the solutions (A) to (E) as defined in 
Example 5. The preparation of the coating composition and the coating of 
the paper are carried out as described in Example 8(b). In each case the 
paper so coated has a degree of whiteness which is distinctly higher than 
that obtained with the formulations (A) to (E) without the compound of 
formula (6). Paper having a similarly high degree of whiteness is obtained 
by substituting the corresponding amount of a fluorescent whitening agent 
of the formula (11), (12), (13), (14) or (15) for that of the formula (10) 
in the solutions (A) to (E). 
EXAMPLE 13 
(a) 600 ml of demineralised water, 10 ml of concentrated ammonia, and 35 g 
of casein are put into a 2 liter glass beaker and heated, with stirring, 
to 70.degree. C. for 10 minutes. Stirring is then continued for 15 minutes 
at 70.degree.-75.degree. C. A turbid, sand-coloured colloidal solution is 
obtained. The casein solution, which is cooled to 30.degree. C., is added 
to a mixture of 50 ml of the sodium salt of a polycarboxylic acid (aqueous 
solution 1:50) and 400 g of China clay SPS. This mixture is slowly stirred 
for 3 minutes. Stirring is then discontinued and any pigment adhering to 
the sides is scraped off. The mixture is then slowly stirred once more for 
2 minutes. Then 3 ml of concentrated ammonia and 80 ml of 
styrene-butadiene latex are stirred in and the batch is slowly stirred for 
a further 3 minutes. Finally, 50 ml of a 4-nonylphenol oxyethylated with 
9.7 moles of ethylene oxide (aqueous solution 1:25) are added and 
stirring is continued for about 15 seconds. The so prepared liquor is 
deaerated and freed from coarser impurities by sieving it through a nickel 
sieve, then put into a 1 liter conical flask and bulked with demineralised 
water to a weight of 1260 g/l. 
(b) To 15 ml of the coating liquor obtained in (a) are added 5 ml of a 
solution consisting of 11.6 g of the fluorescent whitening agent of the 
formula (10), 20 g of the acid phosphoric acid ester of an oxyalkylated 
fatty amine of the formula (6), 10 g of a 4-nonylphenol oxyethylated with 
9.7 moles of ethylene oxide, 15 g of ethylene glycol, 18 g of polyethylene 
glycol 300, and 25.4 g of water. The mixture is homogenised with a 
magnetic stirrer. 
(c) After about 20 minutes, the coating composition obtained in (b) is 
stirred once more and prepared strips of coating paper are coated 
therewith in conventional manner. The degree of whiteness obtained on the 
paper so coated is distinctly higher than that obtained on comparison 
paper which is coated with a coating composition that does not contain the 
compound of formula (6). 
EXAMPLE 14 
The procedure of Example 13(a) is repeated, except that 14 g of the 
compound of the formula (6) are added to the coating composition prepared 
according to Example 13(a). To 15 ml of this coating composition are added 
5 ml of a solution consisting of 11.6 g of the fluorescent whitening agent 
of the formula (10) and 88.4 g of water. The mixture is homogenised with a 
magnetic stirrer. Further processing is as described in Example 13(c). The 
coated paper has a degree of whiteness which is distinctly higher than 
that obtained by coating the paper with a composition which does not 
contain the compound of formula (6). 
Instead of the fluorescent whitening agent of formula (10), it is possible 
to use the fluorescent whitening agents of the formulae (11), (12), (13), 
(14) and (15) with equal success in Examples 13 and 14. 
By substituting an ester of the formula (6a), (6b) or (6c) for the acid 
ester of the formula (6) in Examples 8 to 14 there is obtained, in each 
case, whitened paper which has a higher degree of whiteness than paper 
which is coated with a composition that does not contain such an acid 
ester.