A PROCESS FOR REMOVING PRINTING INKS FROM PRINTED WASTEPAPER

PROCEDE PERMETTANT D'ELIMINER LES ENCRES D'IMPRIMERIE PRESENTES SUR DES PAPIERS DE RECUPERATION

English Abstract

The invention concerns a method of removing printing inks from printed
wastepaper, whereby an additive is added in a metered manner to the process
water and the precipitated solids are then removed by flotation and/or
filtration. The additive contains one or a plurality of amino and/or ammonium
group-containing polymers and/or copolymers, with number average molecular
weights of between 2,000 and 1,000,000, and one or a plurality of cellulose
derivatives. The deinked wastepaper is distinguished by high brightness whilst
the recycled water is very clear.

French Abstract

L'invention concerne un procédé qui permet d'éliminer les encres d'imprimerie présentes sur des papiers de récupération, selon lequel un additif est ajouté de manière dosée à l'eau de traitement et les substances solides détachées pendant le processus sont ensuite éliminées par flottation et/ou par filtration. L'additif renferme un ou plusieurs polymères et/ou copolymères contenant des groupes amino et/ou ammonium dont les poids moléculaires moyens en nombre se situent entre 2.000 et 1.000.000, ainsi qu'un ou plusieurs dérivés cellulose. Les papiers de récupération ainsi désencrés se caractérisent en ce que leur degré de blanc est important et que l'eau de recyclage est simultanément très limpide.

Claims

19
CLAIMS
1. A process for the removal of printing inks from
printed wastepaper, in which an additive is added to the
process water and the solids precipitated are subsequently
removed by flotation and/or filtration, characterized
in that the additive contains
(1) one or more polymers and/or copolymers containing
amino groups and/or ammonium groups with number average
molecular weights in the range from 2,000 to 1,000,000
and
(2) one or more cellulose derivatives.
2. A process as claimed in claim 1, characterized in
that the polymers and/or copolymers containing amino
groups and/or ammonium groups have number average molecular
weights of 5,000 to 500,000 and preferably in the
range from 10,000 to 200,000.
3. A process as claimed in claim 1 or 2, characterized
in that polymers containing amino groups and ammonium
groups obtainable by
a) polymerization of monomers containing amino groups
corresponding to general formula (I):
<IMG> (I)
in which R1 and R2 each represent a hydrogen atom or
a methyl group, R3 and R4 each represent a hydrogen atom
or an alkyl group containing 1 to 4 carbon atoms or a
piperazine, piperidine or morpholine group and R5 is a
linear or branched alkyl radical containing 1 to 22
carbon atoms, with the proviso that the counterion to the
ammonium function is a halogen, sulfate, phosphate,
borate or organic acid anion or an electron pair, Z is

oxygen or NH and n is a number of 2 to 5,
or by
b) copolymerization of monomers corresponding to
formula (I) with
b1) monomeric unsaturated acids corresponding to
general formula (II):
<IMG> (II)
in which R5 and R6 each represent a hydrogen atom or
a methyl group and/or
b2) monomeric unsaturated carboxylic acid esters
corresponding to general formula (III):
<IMG> (III)
in which R7 and R8 each represent a hydrogen atom or
a methyl group and R9 is a linear or branched alkyl group
containing 1 to 22 carbon atoms, m is a number of 2 to 4
and p is a number of 0 to 18, with the proviso that,
where p = 0, the content of unsaturated carboxylic acid
esters in the copolymer does not exceed 90% by weight,
and/or
b3) acrylamides and/or methacrylamides which may be
substituted at the amide nitrogen atoms by linear and/or
branched alkyl radicals containing 1 to 22 carbon atoms
and/or
b4) N-vinyl pyrrolidone,
or by
c) reaction of polymers containing carboxyl groups and/or
ester groups which correspond to the general formula -
COOR10, where R10 is an alkyl group containing 1 to 8

21
carbon atoms, and/or an anhydride group -CO-O-CO- with -
based on the carboxyl, ester and/or latent carboxyl
groups present in these polymers -
c1) 0 to 1 equivalent of aminoalcohols corresponding
to general formula (IV):
<IMG> (IV)
in which R11 is an alkylene group containing 1 to 8
carbon atoms or an aromatic group, R12 and R13
independently of one another represent alkyl groups
containing 1 to 4 carbon atoms or an aromatic group and
the substituents R12 and R13 together with the N atom
represent a piperazine, piperidine or morpholine group, x
is a number of 2 to 4 and y is a number of 0 to 10,
C2) 0 to 1 equivalent of diamines corresponding to
general formula (V):
NHR14 - R15 - NR16R17 (V)
in which R15 is an alkylene group containing 1 to 8
carbon atoms or an aromatic group, R14 is hydrogen or an
alkyl group containing 1 to 4 carbon atoms, R16 and R17
independently of one another represent alkyl groups
containing 1 to 4 carbon atoms or R16 and R17 together
represent -CH=CH-N=CH-,
c3) 0 to 0.5 equivalent of alcohols corresponding
to general formula (VI):
HO - (CaH2aO)b-R18 (IV)
in which R10 is an alkyl group containing 6 to 22
carbon atoms or an aromatic group, a is a number of 2 to

22
4 and b is a number of 0 to 30 and
c4) 0 to 0.5 equivalent of amines corresponding to
general formula (VII):
NHR19R20 (VII)
in which R19 is hydrogen or an alkyl group containing
1 to 4 carbon atoms and R20 is an alkyl group containing 6
to 22 carbon atoms or an aromatic group, with the proviso
that the sum total of the equivalents of components c1)
and c2) is not 0,
are used.
4. A process as claimed in claim 1 or 2, characterized
in that polymers and/or copolymers containing amino
groups and/or ammonium groups, polyethyleneimines and/or
copolymers containing ethyleneimine are used, optionally
in combination with other at least partly water-soluble
polymers and/or copolymers containing amino groups and/or
ammonium groups with number average molecular weights of
2,000 to 1,000,000.
5. A process as claimed in claims 1 or 2, characterized
in that polymers based on 2-vinyl pyridine, 4-vinyl
pyridine and/or 1-vinyl imidazole, optionally in combination
with other at least partly water-soluble polymers
and/or copolymers containing amino groups and/or ammonium
groups with number average molecular weights of 2,000 to
1,000,000, are used as the polymers and/or copolymers
containing amino groups and/or ammonium groups.
6. A process as claimed in claim 1 or 2, characterized
in that primary, secondary, tertiary and/or quaternary
polysaccharides and/or heteropolysaccharides containing
ammonium groups, optionally in combination with other at
least partly water-soluble polymers and/or copolymers
containing amino groups and/or ammonium groups with
number average molecular weights of 2,000 to 1,000,000,

23
are used as the polymers and/or copolymers containing
amino groups and/or ammonium groups.
7. A process as claimed in claim 1 or 2, characterized
in that proteins, optionally in combination with other at
least partly water-soluble polymers and/or copolymers
containing amino groups and/or ammonium groups with
number average molecular weights of 2,000 to 1,000,000,
are used as the polymers and/or copolymers containing
amino groups and/or ammonium groups.
8. A process as claimed in claims 1 to 7, characterized
in that cellulose ethers, such as carboxymethyl cellulose,
methyl cellulose, hydroxyalkyl cellulose, and mixed
ethers, such as methyl hydroxyethyl cellulose, methyl
hydroxypropyl cellulose, methyl carboxymethyl cellulose
and mixtures thereof are used as the cellulose derivatives.
9. A process as claimed in any of claims 1 to 8,
characterized in that the cellulose derivatives are used
in a quantity of 0.01 to 2.5% by weight of active substance,
based on air-dry paper used.
10. A process as claimed in any of claims 1 to 9,
characterized in that the polymers and/or copolymers
containing amino groups and/or ammonium groups are used
in a quantity of 0.02 to 5% by weight of active substance,
based on air-dry paper used.
11. A process as claimed in any of claims 1 to 10,
characterized in that the cellulose derivatives are added
during the refining step while the polymer and/or copolymer
containing amino groups and/or ammonium groups is/are
added immediately before flotation.
12. A process as claimed in any of claims 1 to 11,
characterized in that components 1) and 2) are used in
combination with a flotation collector and/or an inorganic
flocculant.

24
13. A process as claimed in any of claims 1 to 12,
characterized in that the solids separated by flocculation
are removed by flotation.

Description

CA 02206006 1997-0~-26
H 1130 PCT / 22.11.1994
A process for ~ ~ving printing inks from
printed wastepaper
Field of the Invention
This invention relates to a process for removing
printing inks from printed wastepaper in the presence of
polymers and/or copolymers containing amino and/or
ammonium groups with number average molecular weights in
5 the range from 2,000 to 1,000,000 and cellulose deriva-
tives and to the use of the polymers containing amino
and/or ammonium groups and cellulose derivatives for the
removal of printing inks from printed wastepaper.
Prior Art
Today, wastepaper is used in large quantities for
the product on of, for example, newsprint and sanitary
paper. Lightness and color are important quality fea-
tures for papers of this type. To achieve this, the
15 printing inks have to be removed from the printed waste-
paper. Th:is is normally done by so-called deinking
processes. These processes are carried out in standard
wastepaper recycling plants provided with additional
equipment for removing the detached printing ink ar-
20 ticles. Two important process steps in this regard are:
(1) Refining of the wastepaper. By refining is meantthe process of fiberizing the wastepaper. It may be
induced, for example, in aqueous medium by application of
25 mechanical energy (stirring). Fiberizing is accompanied
by detachment of the printing ink particles. The print-
ing ink particles disintegrate into very small particles
between 0.1 and 1,000 ~m in size and are present in
finely dispersed form. The refining step gives a grey

CA 02206006 1997-0~-26
H 1130 PCT 2
paper stock suspension.
(2) Removal of the detached printing ink particles from
the paper stock suspension. This step of the deinking
5 process may be carried out by washing or flotation (cf.,
for example, Ullm~nns Encyclopadie der Technischen
Chemie, 4th Edition, Vol. 17, pages 570-571 (1979)).
The deinking of wastepaper is normally carried out
at alkaline pH values in the presence of alkali metal
10 hydroxides, alkali metal silicates, oxidative bleaching
agents and surface-active agents at temperatures in the
range from 30 to 50~C. The surface-active agents used
are mostly anionic and/or nonionic surfactants, for
example soaps, ethoxylated fatty alcohols and/or ethoxy-
15 lated alkylphenols (cf., for example, Woch~nhl~tt furPapierfabrikation, 17, 646-6~9 (1985)).
The remc,val of water-based printing inks under the
usual alkaline deinking conditions has proved to be
particularly problematical. In contrast to conventional
20 oil-based printing inks, the binders and dispersant
compounds of water-based printing inks can be dissolved
or redispersed under the conditions mentioned. The
printing ink itself breaks up and disintegrates into very
small particles. These particles are additionally
25 stabilized b~ adsorption of the dispersants on the
surface of the pigments. These very small colored
particles remain on the fibers and cannot be removed
under the usual washing and flotation conditions, result-
ing in serious grey discoloration of the paper produced
30 from the raw materials.
According to ctp, Centre Technique du Papier, 1st
Research Forl~n on Recycling, 29th - 31st October, 1991,
the use of carboxymethyl cellulose can reduce the deposi-
tion of print-Lng inks, but does not lead to any improve-

CA 02206006 1997-0~-26
~.
H 1130 PCT 3
ment in color.
In addition to the printing inks mentioned, water-
soluble or colloidally dissolved and finely dispersed
solids enter the process waters of the paper making
5 process ancl accumulate undesirably therein at constric-
tions in the circuit. These solids are, above all,
fillers and fine fibers.
On account of the adverse effects of these solids,
the water generally has to be cleaned in the case of
10 closed water circuits and at constrictions in the cir-
cuit. This is normally done by flocculation, precipita-
tion, adsorption and flotation processes or combinations
thereof (cf. for example J. Schurz, Wo~nhl~tt fur
Papierfabrikation 1990, 3, 109-118). Wash deinking
15 plants normally operate, for example, on the prlnciple of
microflotation where the suspended solids and the dis-
solved and colloidal substances are flocculated and then
floated out from the water (cf., for example, K. Schnab-
el, Wo~h~nhl;~tt fur Papierfabrikation, 1990, 6, 233-237).
Typical flocculants in the treatment of process
waters in the paper making industry include inorganic and
organic flocculants, such as milk of lime, aluminium or
iron salt solutions, cationic polymers, such as polyethy-
leneimine, cationic starches, polyamidoamine/epichloro-
25 hydrin resins and melamine/formaldehyde resins (cf. the
above-mentioned article by W. Auhorn and J. Schurz). A
flocculant particularly preferred by experts is poly-
diallyl dimethylammonium chloride (cf., for example, R.
Nicke et al., Wochenblatt fur Papierfabrikation 1992, 14,
30 559-564 and the above-mentioned article by J. Schurz).
This compound, which is normally referred to as poly-
DADMAC, is a linear molecule which carries a positive
charge at the nitrogen atom in each of the recurring
structural units. Towards the outside, this positive

CA 02206006 1997-0~-26
H 1130 PCT 4
charge is neutralized by a negatively charged chloride
ion. Overal:L, a polyelectrolyte with a very high charge
density is thus formed.
Description of the Invention
The problem addressed by the present invention was
to provide a process for the removal of printing inks
from printed wastepaper. More particularly, this process
would improve the whiteness of the paper obtained and,
10 optionally, would also remove finely dispersed solids
from the process waters to ml~lm; ze soiling of the
process water.
It has now been found that a combination of polymers
and/or copolymers containing amino groups and/or ammonium
15 groups and cellulose derivatives is particularly suitable
for the treatment of circuit waters and wastewaters in
paper manufacture.
The present invention relates to a process for the
removal of printing inks from printed wastepaper, in
20 which an additive is added to the process water and the
solids precipitated are subsequently removed by flotation
and/or filtration, the additive containing
(1) one or more polymers and/or copolymers containing
amino groups and/or ammonium groups with number average
25 molecular weights in the range from 2,000 to 1,000,000
and
(2) one or more cellulose derivatives.
In the presence of a combination of polymers con-
taining amino groups and/or ammonium groups and cellulose
30 derivatives, printing inks, for example newsprint inks,
book printing inks, offset printing inks, magazine
gravure printing inks, flexographic printing inks, laser
printing inks and/or packaging gravure printing inks, can
be removed from printed wastepaper, for example news-

CA 02206006 1997-0~-26
H 1130 PCT 5
papers, magazines, computer paper, journals, brochures,
forms, telephone directories and/or catalogs. The
wastepapers deinked in the presence of the combination
used in accordance with the invention are distinguished
5 by high degrees of whiteness.
At least partly water-soluble polymers and/or
copolymers containing amino groups and/or ammonium groups
with number average molecular weights in the range from
5,000 to 500,000 are preferably used, those having number
10 average molecular weights in the range from 10,000 to
200,000 being particularly preferred.
At l easl partly water-sol ubl e means that more than
0.01~ by weight of the polymers and/or copolymers form
clear or clc)udy solutions in water at the in-use pH
15 value.
At lea, t partly water-sol ubl e polymers and/or
copolyme~s containing amino groups in the context of the
invention also include polymers containing pyridine
groups, for example polymers based on 2-vinyl pyridine
20 and/or 4-vinyl pyridine.
A partic:ularly preferred group of polymers for the
process according to the invention is obtainable by
a) polymerization of monomers containing amino groups
corresponding to general formula (I):
o R5
R1 - CH == CR2 - C - Z - (CnH2n) - I (I)
\~4
in which R1 and R2 each represent a hydrogen atom or
a methyl group, R3 and R4 each represent a hydrogen atom
35 or an alkyl group containing 1 to 4 carbon atoms or a
piperazine, piperidine or morpholine group and R5 is a
linear or branched alkyl radical containing 1 to 22

CA 02206006 1997-0~-26
H 1130 PCT 6
carbon atoms, with the proviso that the counterion to the
ammonium function is a halogen, sulfate, phosphate,
borate or organic acid anion or an electron pair, Z is
oxygen or NH and n is a number of 2 to 5,
5 or by
b) copolymerization of monomers corresponding to
formula (I) with
bl) mon.omeric unsaturated acids corresponding to
general formu.la (II):
o
R5 -- CH = CR6 - C - OH (II)
in which R5 and R6 each represent a hydrogen atom or
a methyl group and/or
b2)monomeric unsaturated carboxylic acid esters
corresponding to general formula (III):
O
R7 - CH = CR8 - C - O - (CmH2mO)p - R9 (III)
in which R7 and R8 each represent a hydrogen atom or
25 a methyl group and R9 is a linear or branched alkyl group
containing 1 to 22 carbon atoms, m is a number of 2 to 4
and p is a number of 0 to 18, with the proviso that,
where p = 0, the content of unsaturated carboxylic acid
esters in the copolymer does not exceed 90% by weight,
30 and/or
b3) acrylamides and/or methacrylamides which may be
substituted at: the amide nitrogen atoms by linear and/or
branched alky] radicals containing 1 to 22 carbon atoms
and/or
b4) N-~Tinyl pyrrolidone,
or by

CA 02206006 1997-0~-26
H 1130 PCT 7
c) reaction of polymers containing carboxyl groups and/
or ester groups which correspond to the general formula -
COOR10, where R10 is an alkyl group containing 1 to 8
carbon atoms, and/or an anhydride group -CO-O-CO- with -
5 based on the carboxyl, ester and/or latent carboxylgroups present in these polymers -
cl) 0 to 1 ec~uivalent of aminoalcohols correspond-
ing to general formula (IV):
R12
/
HO - (CxH2xO)y - R11 - N (IV)
\Rl3
in which R11 is an alkylene group containing 1 to 8
carbon ato~Ls or an aromatic group, R12 and R13
independently of one another represent alkyl groups
containing 1 to 4 carbon atoms or an aromatic group and
20 the substituents R12 and R13 together with the N atom
represent a piperazine, piperidine or morpholine group, x
is a number of 2 to 4 and y is a number of 0 to 10,
C2) 0 to 1 equivalent of diamines corresponding to
general formula (V):
NHRl4 - Rl5 _ NRl6Rl7 (V)
in whic:h R15 is an alkylene group containing 1 to 8
carbon atoms or an aromatic group, R14 is hydrogen or an
30 alkyl group containing 1 to 4 carbon atoms, R16 and R17
independently of one another represent alkyl groups
containing 1 to 4 carbon atoms or R16 and R17 together
represent -C~=CH-N=CH-,
c3) 0 to 0.5 equivalent of alcohols corresponding
35 to general formula (VI):

CA 02206006 1997-0~-26
H 1130 PCT 8
HO ~ (CaH2aO) b--R18 (VI)
in which R18 is an alkyl group containing 6 to 22
carbon atoms or an aromatic group, a is a number of 2 to
5 4 and b is a number of 0 to 30 and
c4) 0 to 0.5 equivalent of amines corresponding to
general formula (VII):
NHR19R20 (VII)
in which R19 is hydrogen or an alkyl group containing
1 to 4 carbon atoms and R20 is an alkyl group containing 6
to 22 carbon atoms or an aromatic group, with the proviso
that the sum. total of the equivalents of components cl)
15 and c2) is not 0.
Suitable aminofunctional monomers corresponding to
general for]~lla I are, in particular, those in which R1
is hydrogen, R2 is hydrogen or methyl, R3 and R4 each
represent methyl or ethyl, R5 is an electron pair or an
20 alkyl group containing 1 to 4 carbon atoms, with the
proviso that the counterion to the ammonium function is a
halogen io:n. Examples are dimethylaminoethyl
methacrylate, dimethylaminoethyl acrylate,
dimethylaminopropyl methacrylamide,
25 dimethylaminoneopentyl acrylate, diethylaminoethyl
acrylate, diethylaminoethyl methacrylate and/or meth-
acrylamidopropyl dimethylammonium chloride.
Acrylic acid and/or methacrylic acid is/are prefer-
ably used as monomeric unsaturated acids corresponding to
30 general formu.la II.
Monomeric unsaturated carboxylic acid esters corre-
sponding to general formula III, in which R9 is
preferably a linear or branched alkyl group containing 1
to 8 carbon a.toms, are for example ethyl acrylate, methyl
35 methacrylate, butyl acrylate, butyl methacrylate, octyl

CA 02206006 l997-0~-26
H 1130 PCT 9
acrylate ancL/or an adduct of 3 moles of ethylene oxide
with butyl acrylate.
In addition, acrylamide, methacrylamide, N-ethyl
acrylamide and/or tert.butyl acrylamide is/are suitable
5 for copol~nerization with aminofunctional monomers
corresponding to general formula I.
The polymerization or copolymerization of the
aminofunctional monomers corresponding to general formula
I is carried out by polymerization processes known per se
10 in ac~ueous media optionally containing water-miscible
solvents, such as alcohols, for example isopropanol. A
radical-forming substance, for example potassium or
ammonium peroxodisulfate, tert.butyl hydroperoxide, azo-
bis-(isobutyronitrile), is added in small quantities as
15 initiator. The polymerization or copolymerization of the
aminofunctional monomers corresponding to general formula
I may be carried out, for example, by simultaneously
adding the monomers I and optionally monomers of groups
bl) to b4) clropwise to water containing the initiator.
20 sasically, the polymerization temperature is not critical
and may vary within wide limits. Temperatures of 60 to
100~C can be optimal according to the initiator used.
Ac~ueous poly~er and/or copolymer solutions with polymer
contents of, for example, 10 to 60% by weight are ob-
25 tained.
If the polymers and/or copolymers containing aminogroups and/or ammonium groups suitable for use in accord-
ance with the invention are produced by esterification or
amidation of carboxyfunctional, ester-functional and/or
30 anhydride-functional polymers with aminoalcohols, di-
amines or amines, the following observations apply:
The carboxyfunctional, ester-functional and/or
anhydride-functional polymers may be produced by known
polymerization processes in organic solvents, such as

CA 02206006 l997-0~-26
H 1130 PCT lO
hexane, octane, toluene, xylene and/or ketones. Suitable
monomers are, for example, acrylic acid, methacrylic
acid, crotonic acid, C1_8 alkyl esters of the above-
mentioned acids, aryl esters of the above-mentioned
5 acids, maleic anhydride, maleic acid, fumaric acid, mono-
C1_8-alkyl est:ers of the above-mentioned acids, di-C18-
alkyl esters of the above-mentioned acids and the corre-
sponding aryl esters. The alkyl group of the alcohol
radicals in the esters may be linear, branched or cyclic.
A monomer or a mixture of monomers may be used. Acrylic
acid, methacrylic acid, acrylates and/or methacrylates
are preferably used as monomers. Styrene, alkyl sty-
renes, 4-vinyl pyridine, N-vinyl pyrrolidone, acrylo-
nitrile, acrylamide, methacrylamide, vinyl chloride
15 and/or vinylidene chloride may be used as further mono-
mers. The polymerizations are carried out in the pres-
ence of radic,~l-forming substances as described above.
The reaction of the carboxyfunctional, ester-func-
tional and/or anhydride-functional polymers with amino-
20 alcohols and/or diamines and optionally alcohols and/oramines is carried out with or without organic solvents,
preferably in the presence of catalysts, such as sulfuric
acid, p-toluene sulfonic acid, dibutyl tin dilaurate, tin
and/or alkali metal alcoholates, at temperatures in the
25 range from 100 to 230~C. The water formed during the
esterification and/or amidation reaction and/or the
alcohols formed are removed by distillation. Suitable
organic solvents are, for example, aliphatic and/or
aromatic hydrocarbons with boiling points above 100~C.
Suitable aminoalcohols cl) corresponding to general
formula IV are, for example, 2-dimethylaminoethanol, 2-
diethylaminoethanol, 3-dimethylamino-2,2-dimethyl-1-
propanol, 4-(dimethylamino)-1-butanol, 6-(dimethylamino)-
1-hexanol, 2-[(2-dimethylamino)-ethoxy]-ethanol, 2-di-

CA 02206006 1997-0~-26
H 1130 PCT 11
butylaminoethanol, 3-dimethylamino-1-propanol, 3-diethyl-
amino-1-propanol, 4-dimethylaminophenol, 3-diethylamino-
phenol, N-hyclroxyethyl-N-methyl aniline, N-hydroxyethyl-
N-ethyl aniline and/or 4-(2-hydroxyethyl)-morpholine.
Examples of diamines c2) corresponding to general
formula V are~ N,N-dimethylaminopropylamine, N,N-diethyl-
aminopropylamine, N,N-diethylaminoethylamine, 1-diethyl-
amino-4-aminopentane, N,N-dimethyl-p-phenylenediamine,
N,N-diethyl-p-phenylenediamine and/or 1-(3-aminopropyl)-
10 imidazole.
The reactions of carboxyfunctional, ester-functional
and/or anhydride-functional polymers with aminoalcohols
and/or diamines may be carried out in the presence of
alcohols c3) corresponding to general formula VI and/or
15 amines c4) corresponding to general formula VII. The
alkyl g~oups present in the alcohols and/or amines may be
linear, branched and/or cyclic. Examples of alcohols
corresponding to general formula VI are cyclohexanol, 2-
ethylhexanol, octanol, decanol, dodecanol, tetradecanol,
20 hexadecanol, octadecanol, docosanol, an adduct of 12
moles of ethylene oxide with tallow alcohol and also
benzyl alcohol. Examples of amines corresponding to
general formula VII are hexylamine, 2-ethylhexylamine,
octylamine, clecylamine, dodecylamine, tetradecylamine,
25 hexadecylamine, octadecylamine, docosylamine, cocoamine
and tallow amine.
Another particularly preferred group of polymers for
the process according to the invention are polyethylene-
imines and/or copolymers containing ethyleneimine. They
30 may optionally be used together with other at least
partly water-soluble polymers and/or copolymers contain-
ing amino groups and/or ammonium groups with number
average molecular weights in the range from 2,000 to
500,000.

CA 02206006 1997-0~-26
H 1130 PCT 12
In addition, polymers and/or copolymers based on 2-
vinyl pyridine, 4-vinyl pyridine and/or 1-vinyl imida-
zole, for example poly-4-vinyl pyridine, copolymers of 1-
vinyl imidazole and N-vinyl pyrrolidone with vinyl
5 imidazole contents of 10 to 90~ by weight, optionally in
combination with other at least partly water-soluble
polymers and/or copolymers containing amino groups and/or
ammonium groups with number average molecular weights in
the range from 2,000 to 500,000, are also particularly
10 suitable for deinking wastepaper. The production of
these polymers and/or copolymers is carried out by
polymerization processes known per se, for example in
bulk in th.e presence of radical-forming substances
(Ullm~nn.s EnGyclopadie der te~,hni schen Chemie, 4th
15 Edition, Vol. 23, pages 611-614, Verlag Chemie Weinheim,
1983).
Primary, secondary, tertiary and/or quaternary
aminofunctional polysaccharides and/or heteropolysac-
charides and/or derivatives thereof, which may optionally
20 be used in combination with other at least partly water-
soluble polymers and/or copolymers containing amino
groups and/or ammonium groups with number average molecu-
lar weights of 2,000 to 500,000, are another particularly
preferred group of polymers for the deinking process
25 according to the invention. At least partly water-
soluble pri.mary, secondary, tertiary and/or quaternary
aminofunctior-al celluloses, hydroxyethyl celluloses,
starches, chitosan and/or guar are examples of primary,
secondary, _ertiary and/or quaternary aminofunctional
30 polysacchar:ides and/or heteropolysaccharides. The
introduction of tertiary and/or quaternary amino groups
into polysaccharides and/or heteropolysaccharides free
from amino groups is carried out in known manner by
reacting polysaccharides and/or heteropolysaccharides

CA 02206006 1997-0~-26
H 1130 PCT 13
with tertiary amines containing a glycidyl group and/or
with ammonium compounds (US 3,472,840). Dimethyl gly-
cidylamine amine and 3-chloro-2-hydroxypropyl trimethyl-
ammonium chloride are examples of tertiary amines and
5 ammonium compounds.
In addition, water-dilutable printing inks can be
removed particularly effectively from wastepaper in the
presence of proteins, optionally in combination with
other at least partly water-soluble polymers and/or
10 copolymers containing amino groups and/or ammonium groups
with number average molecular weights in the range from
2,000 to 500,000.
In one preferred embodiment of the present inven-
tion, the polymers mentioned are used in a cluantity of
15 0.05 to 1% by weight of active substance, based on the
paper used.
Cellulose derivatives suitable for use in the
process according to the invention are, in particular,
the cellulose ethers such as, for example, carboxymethyl
20 cellulose, methyl cellulose, hydroxyalkyl cellulose, and
mixed ethers, such as methyl hydroxyethyl cellulose,
methyl hydroxypropyl cellulose, methyl carboxymethyl
cellulose and mixtures thereof, carboxymethyl cellulose
(Na salt), methyl cellulose and methyl hydroxyethyl
25 cellulose being preferred. The cellulose derivatives are
preferably used in quantities of 0.01 to 2.5% by weight
and preferably in quantities of 0.02 to 1~ by weight of
active substance, based on the paper used.
In many cases, the degree of removal of printing
30 inks can be further increased if the components used in
the process according to the invention are combined with
flotation collectors and/or inorganic adsorbents or
flocculants.
Examples of flotation collectors are C10_22 fatty

CA 02206006 1997-0~-26
H 1130 PCT 14
acids and alkali metal or alkaline earth metal salts
thereof, alkoxylated C6_22 alkyl alcohols or alkoxylated
alkylphenols, other cationic polymers such as, for
example, pclydimethylaminoethyl methacrylate and/or
5 copolymers of the type described, for example, in DE 38
39 479. The fatty acids mentioned and also fatty alcohol
alkoxylates with a high percentage content of alkylene
oxide, more particularly ethylene oxide, are most par-
ticularly suitable. Examples of flocculants are milk of
10 lime, aluminium or iron salt solutions. These components
may be used in a quantity of 0.05 to 1% by weight, based
on the air-dry paper stock.
The printing inks may be removed from wastepaper,
for example, by the following method: in a pulper,
15 printed wastepaper is size-reduced at temperatures of 20
to 60~C and at a stock consistency of, for example, 0.5
to 5% by weight in an aqueous solution typically contain-
ing 0 to 1.5% by weight of hydrogen peroxide (100%), 0 to
2.5% by weight of sodium hydroxide (99% by weight), 0 to
20 4.0% by weight of soda waterglass with a solids content
of 35% by weight, 0.02 to 2% by weight of the polymers
containing amino groups and/or ammonium groups defined
above and 0.01 to 1.5% by weight of cellulose derivatives
and 0 to 1% by weight of the above-mentioned optional
25 constituents (all percentages by weight based on air-dry
wastepaper). After a residence time of typically 60 to
120 minutes at temperatures of 20 to 60~C, more water is
stirred into or added to the paper stock suspensions so
that 0.6 to 1.6% by weight paper stock suspensions are
30 obtained. The detached printing ink particles are then
separated from the paper stock suspensions in known
manner by washing or flotation. Flotation is preferably
carried out in known manner, for example in a Denver
flotation cell (laboratory scale).

f CA 02206006 1997-0~-26
H 1130 PCT 15
If water-based flexographic printing inks are to be
removed from wastepaper, it is advisable to modify the
process to lhe extent that the cellulose derivative is
actually added in the pulper at a fiber concentration of
5 around 4% by weight and the above-defined polymer con-
taining amino groups and/or ammonium groups is added
immediately before flotation.
By using a cellulose derivative in combination with
a polymer containing amino and/or ammonium groups in
10 accordance with the invention, printing inks can be more
easily removed both from wastepaper and from the circuit
water. However, the compounds to be used in accordance
with the invention may also be used for the separate
purification of paper circuit waters, i.e. wastewaters
15 still contalning certain quantities of printing inks. In
these cases, the printing ink particles are separated,
for example by filtration or flotation, after the addi-
tion of 0.5 to 300 mg of the components per liter of
circuit water.
The following Examples are intended to illustrate
the invention without limiting it in any way.
E x a m p l e s
25 1. Removal of printing inks from alkaline medium
1.1 Refinir~Sr
An aqueous suspension of 17.5 g of air-dry, shredded
wastepaper ~50% Stern, 15% Rheinische Post, 15% Express,
20~ Flexo 1 6/90) with a consistency of 4% by weight was
30 introduced into a stirred vessel. After
a) 2.0% by weight of soda waterglass with a solids
content of 35% by weight (37 to 40~Bé),
b) 1.0~ by weight of sodium hydroxide (99~ by weight),

CA 02206006 1997-0~-26
H 1130 PCT 16
c) 0.7~ by weight of hydrogen peroxide (100~) and
d) 0.2% by weight of a cellulose derivative (cf. Table
1)
5 had been successively added to this suspension (all
percentages by weight based on air-dry paper stock), the
suspended paper shreds were size-reduced for 10 minutes
at 45~C us:ing a dissolver disk (Pendraulik Type 34
laboratory mixer). The paper stock obtained in this way
10 was left standing for 105 minutes at 45~C.
1.2 Printing ink flotation (~i nki ng)
The paper stock obtained in accordance with 1.1 was
diluted with water (hardness 16~dH) to a consistency of
15 1% by weight. 0.2% by weight, based on the paper used,
of a polymer containing amino groups and/or ammonium
groups (cf. I'able 1) in the form of an aqueous solution
was then added. The paper stock was floated in a Denver
laboratory flotation cell for 12 minutes at 45~C at a
20 speed of 1000 r.p.m. After flotation, the paper stock
obtained was separated from water on a filter nutsche,
formed into a sheet between two filter papers in a photo
dry press and dried for 90 minutes at 100~C.
25 2. Test results
Particulars of the tests described under 1. are set
out in Table 1 below. It can be seen from Table 1 that
excellent results are obtained in the process according
to the invention both in regard to the whiteness of the
30 stock and in regard to the color of the circuit water
(measured as ~ransmission).
Table 1

CA 02206006 1997-05-26
t
H 1130 PCT 17
41 81 61 71 5
¦Example IPolymer ¦Cellulose der. ¦Whiteness ¦Water
~ 1% Refl. 1%
Transm.¦
1 1 1 1
¦ ~-1 ¦ A I _ ¦ 51-9 ¦ 93
.-1 A Clllmin~l~ MHPC 55.9 96
~1 1 1 1 1
1 1 1
.~-2 A Culminalt~ MC 53.1 96
25-S
-

CA 02206006 1997-0~-26
H 1130 PCT 18
Copolymer of 73% by weight of dimethylaminoethyl
methacrylate, 11~ by weight of acrylic acid and 16%
by weight of methyl methacrylate
Methyl hydroxypropyl cellulose (a product of
Aqualon)
Methyl cellulose (a product of Aqualon)
Example C-1 is intended for comparison while
Examples E-1 and E-2 correspond to the invention
Color o:f the circuit water (expressed in %
transmission)
Cellulo,e derivative used (0.1% by weight)
Whitene.,s of the deinked paper (expressed in %
reflectance )
Polymer used (0.2% by weight)