U.S. patent application number 11/809606 was filed with the patent office on 2007-12-06 for sizing of paper.
This patent application is currently assigned to AKZO NOBEL N.V.. Invention is credited to Agneta Lernbrink, Jonas Liesen, Kristina Mohlin, Jeanette Risen.
Application Number | 20070277949 11/809606 |
Document ID | / |
Family ID | 38788758 |
Filed Date | 2007-12-06 |
United States Patent
Application |
20070277949 |
Kind Code |
A1 |
Liesen; Jonas ; et
al. |
December 6, 2007 |
Sizing of paper
Abstract
The present invention relates to a process for the production of
paper which comprises: (a) providing an aqueous cellulosic
suspension; (b) separately adding to the suspension: (i) a
nitrogen-containing organic compound having a molecular weight less
than 1,000; and (ii) a cellulose-reactive sizing agent; and (c)
dewatering the obtained suspension to form paper. The invention
further relates to a process in which a nitrogen-containing organic
compound having a molecular weight less than 1,000 is mixed with an
aqueous dispersion of a cellulose-reactive sizing agent to form a
pre-mix and which premix is added to the suspension.
Inventors: |
Liesen; Jonas; (Jorlanda,
SE) ; Risen; Jeanette; (Goteborg, SE) ;
Mohlin; Kristina; (Ytterby, SE) ; Lernbrink;
Agneta; (Alvangen, SE) |
Correspondence
Address: |
AKZO NOBEL INC.
INTELLECTUAL PROPERTY DEPARTMENT, 120 WHITE PLAINS ROAD 3RD FLOOR
TARRTOWN
NY
10591
US
|
Assignee: |
AKZO NOBEL N.V.
Arnhem
NL
|
Family ID: |
38788758 |
Appl. No.: |
11/809606 |
Filed: |
May 31, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60810677 |
Jun 1, 2006 |
|
|
|
Current U.S.
Class: |
162/158 ;
162/179; 162/183 |
Current CPC
Class: |
D21H 17/07 20130101;
D21H 23/04 20130101; D21H 21/16 20130101; D21H 17/17 20130101 |
Class at
Publication: |
162/158 ;
162/183; 162/179 |
International
Class: |
D21H 17/07 20060101
D21H017/07; D21H 17/17 20060101 D21H017/17 |
Claims
1. Process for the production of paper which comprises: (a)
providing an aqueous cellulosic suspension; (b) separately adding
to the suspension: (i) a nitrogen-containing organic compound
having a molecular weight less than 1,000; and (ii) a
cellulose-reactive sizing agent; and (c) dewatering the obtained
suspension to form paper.
2. Process according to claim 1, wherein the nitrogen-containing
organic compound is a quaternary ammonium compound.
4. Process according to claim 1, wherein the nitrogen-containing
organic compound is added to the cellulosic suspension prior to
adding the cellulose-reactive sizing agent.
5. Process according to claim 1, wherein the nitrogen-containing
organic compound is added to the cellulosic suspension
simultaneously with the cellulose-reactive sizing agent.
6. Process according to claim 1, wherein the nitrogen-containing
organic compound is added to the cellulosic suspension after the
cellulose-reactive sizing agent.
7. Process according to claim 1, wherein the nitrogen-containing
organic compound comprises any one of methyl bis[ethyl
(tallowate)]-2-hydroxyethyl ammonium methyl sulphate,
di(hydrogenated tallow)dimethylammonium chloride, di(hydrogenated
tallow fatty acids-2-hydroxyethyl ester) dimethyl ammonium
chloride, didecyldimethylammonium chloride,
(vegetableoil)benzyl-dimethylammonium chloride,
(dodecyl)benzyl-dimethylammonium chloride or quaternary
imidazolinium compound.
8. Process according to claim 1, wherein the cellulose-reactive
sizing agent is a ketene dimer.
9. Process according to claim 1, wherein the sizing agent is added
as an aqueous dispersion.
10. Process according to claim 1, wherein the nitrogen-containing
organic compound is added in an amount of greater than 20% by
weight based on the weight of the cellulose-reactive sizing
agent.
11. Process according to claim 1, wherein the nitrogen-containing
organic compound is added in an amount of 0.005 to 0.5% by weight,
based on the dry weight of the aqueous cellulosic suspension.
12. Process according to claim 1, wherein the sizing agent is added
in an amount of 0.01 to 1.0% by weight, based on the dry weight of
the aqueous cellulosic suspension.
13. Process for the production of paper which comprises: (a)
providing an aqueous cellulosic suspension; (b) separately adding
to the suspension: (i) a nitrogen-containing organic compound which
is a quaternary ammonium compound having a molecular weight less
than 1,000; and (ii) an aqueous dispersion of a cellulose-reactive
sizing agent which is a ketene dimer; and (c) dewatering the
obtained suspension to form paper.
14. Process according to claim 13, wherein the nitrogen-containing
organic compound comprises any one of methyl bis[ethyl
(tallowate)]-2-hydroxyethyl ammonium methyl sulphate,
di(hydrogenated tallow)dimethylammonium chloride, di(hydrogenated
tallow fatty acids-2-hydroxyethyl ester) dimethyl ammonium
chloride, didecyldimethylammonium chloride,
(vegetableoil)benzyl-dimethylammoniumchloride, or
(dodecyl)benzyl-dimethylammonium chloride.
15. Process according to claim 13, wherein the nitrogen-containing
organic compound comprises quaternary imidazolinium.
16. Process for the production of paper which comprises: (a)
providing a cellulosic suspension; (b) mixing a nitrogen-containing
organic compound having a molecular weight less than 1,000 with an
aqueous dispersion of a cellulose-reactive sizing agent to form a
pre-mix, wherein the mixing is carried out by bringing an aqueous
stream of the nitrogen-containing organic compound into a contact
with an aqueous stream of the sizing agent and introducing the
resulting stream into the cellulosic suspension; (c) adding the
pre-mix to the suspension; and (d) dewatering the obtained
suspension to form paper.
17. Process according to claim 16, wherein a contact time of the
nitrogen-containing organic compound and the aqueous dispersion of
the sizing agent in the pre-mixture is less than 20 minutes before
the addition.
18. Process according to claim 16, wherein the nitrogen-containing
organic compound comprises any one of methyl bis(ethyl
(tallowate)]-2-hydroxyethyl ammonium methyl sulphate,
di(hydrogenated tallow)dimethylammonium chloride, di(hydrogenated
tallow fatty acids-2-hydroxyethyl ester) dimethyl ammonium
chloride, didecyldimethylammonium chloride,
(vegetableoil)benzyl-dimethylammoniumchloride,
(dodecyl)benzyl-dimethylammonium chloride or quaternary
imidazolinium compound.
19. Process according to claim 16, wherein the cellulose-reactive
sizing agent is a ketene dimer.
20. Process according to claim 16, wherein the nitrogen-containing
organic compound is added in an amount of greater than 20% by
weight, based on the weight of the cellulose-reactive sizing agent.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates sizing of paper and
paper board.
BACKGROUND OF THE INVENTION
[0002] Cellulose-reactive sizing agents, such as those based on
alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA), are
widely used in papermaking at neutral or slightly alkaline stock
pH's in order to give paper and paper board some degree of
resistance to wetting and penetration by aqueous liquids. Paper
sizes based on cellulose-reactive sizing agents are generally
provided in the form of dispersions containing an aqueous phase and
finely divided particles or droplets of the sizing agent dispersed
therein.
[0003] Cellulose-reactive sizing agents generally provide good
sizing effect using low dosages of the sizing agent when added to
the aqueous cellulosic suspension. The sizing effect starts to
develop in the drying section of the paper machine. However, since
most paper machines operate at maximum speed to optimize the paper
production, the time in the drying section is often not long enough
to produce sized paper on-machine. Instead the paper has to be
allowed to cure for up to 24 hours before a fully sized product can
be achieved. This slow development of the sizing effect creates a
number of problems. Firstly, subsequent operations such as
printing, coating, pasting, etc. may be difficult to handle.
Secondly, many paper makers continuously overdose the sizing agents
to make sure that a fully sized product is achieved. Consequently,
problems in terms of deposits on machine components are usually
created.
[0004] WO 9710387 discloses a paper sizing enhancer which is a
polymerization reaction product of a quaternary diallylammonium
monomer and a diallylammonium monomer. The polymerization product
has a molecular weight of at least 10,000. WO 9710387 discloses
that the paper sizing enhancer may be introduced into a paper
furnish during the papermaking process in combination with the
paper sizing agent, either separately or as an aqueous medium
containing both components.
[0005] WO 02081587 discloses a sizing dispersion containing a
sizing agent and a non-ionic surface active monoester of glycerol
with a fatty acid.
[0006] It is an object of this invention to provide a process for
the production of paper with improved initial sizing on-machine. It
is also an object of the invention to provide faster curing times
for sizing agent. Further objects will appear hereinafter.
SUMMARY OF THE INVENTION
[0007] The present invention concerns a process for the production
of paper which comprises:
[0008] (a) providing an aqueous cellulosic suspension;
[0009] (b) separately adding to the suspension: [0010] (i) a
nitrogen-containing organic compound having a molecular weight less
than 1,000; and [0011] (ii) a cellulose-reactive sizing agent;
and
[0012] (c) dewatering the obtained suspension to form paper.
[0013] The present invention further concerns a process for the
production of paper which comprises:
[0014] (a) providing a cellulosic suspension;
[0015] (b) mixing a nitrogen-containing organic compound having
molecular weight less than 1,000 with an aqueous dispersion of a
cellulose-reactive sizing agent to form a pre-mix;
[0016] (c) adding the pre-mix to the suspension; and
[0017] (d) dewatering the obtained suspension to form paper.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In accordance with the present invention it has surprisingly
been found that improved initial sizing, i.e. faster development of
the sizing effect or faster curing of paper, in papermaking can be
achieved by separately adding to a cellulosic suspension a
nitrogen-containing organic compound having a molecular weight of
less than 1,000 and a cellulose-reactive sizing agent. It has also
been found that improved initial sizing can be achieved by adding
to the suspension a pre-mix of the nitrogen-containing organic
compound and an aqueous dispersion of a cellulose-reactive sizing
agent. Faster curing provides faster feedback on sized products,
minimizes the risk of overdosing the sizing agent which, in turn,
may result in less deposits in the paper machine. Hereby improved
runnability of the paper machine can be achieved. Due to faster
curing times, less storage space for paper rolls to be cured will
be required. The present invention thus offers substantial
economical and technical benefits.
[0019] The nitrogen-containing organic compound according to the
invention can be selected from primary amines, secondary amines,
tertiary amines, quaternary amines, which are also referred to as
quaternary ammonium compounds. The nitrogen-containing compound is
preferably water-soluble or water-dispersible and it can be
aromatic, i.e. containing one or more aromatic groups, or
aliphatic; the aliphatic nitrogen-containing water-dispersible
organic compounds usually being preferred. The nitrogen-containing
organic compound can be uncharged or cationic. Suitable
nitrogen-containing organic compounds include acid addition salts
of primary, secondary and tertiary amines and, preferably,
quaternary ammonium compounds. The nitrogen-containing organic
compound may have one or more oxygen-containing substituents, for
example with oxygen in the form of hydroxyl groups and/or alkyloxy
groups. Examples of preferred substituents of this type include
hydroxyl groups, e.g. ethanol groups, and methoxy and ethoxy
groups. The nitrogen-containing organic compounds may include one
or more nitrogen atoms, preferably one or two. The
nitrogen-containing organic compound has a molecular weight of less
than 1,000, suitably less than 900 or 800 and preferably less than
750 or 600. Usually, the molecular weight of the
nitrogen-containing organic compound is at least 250, preferably at
least 330.
[0020] Examples of suitable nitrogen-containing organic compounds
include compounds prepared by reacting a primary, secondary or
tertiary amine with methyl chloride, dimethyl sulphate and benzyl
chloride. Examples of suitable quaternary ammonium compounds
further include compounds having the general formula R.sub.4N.sup.+
X.sup.-, wherein each R group is independently selected from (i)
hydrogen; (ii) hydrocarbon groups, suitably aliphatic and
preferably alkyl groups, having from 1 to about 30 carbon atoms,
preferably from 1 to 22 carbon atoms; and (iii) hydrocarbon groups,
suitably aliphatic and preferably alkyl groups, having up to about
30 carbon atoms, preferably from 4 to 22 carbon atoms, and being
interrupted by one or more heteroatoms, e.g. oxygen or nitrogen,
and/or groups containing a heteroatom, e.g. carbonyl and acyloxy
groups; where at least one, suitably at least three and preferably
all of said R groups contain carbon atoms; suitably at least one
and preferably at least two of said R groups containing at least 7
carbon atoms, preferably at least 9 carbon atoms and most
preferably at least 12 carbon atoms; and wherein X.sup.- is an
anion, typically a halide like chloride. The nitrogen-containing
organic compound of the invention is preferably substantially free
from silica-based particles.
[0021] Examples of suitable primary amines, i.e. amines having one
organic substituent, include alkylamines, e.g. propylamine,
butylamine, cyclohexylamine, alkanolamines, e.g. ethanolamine, and
alkoxyalkylamines, e.g. 2-methoxyethylamine. Examples of suitable
secondary amines, i.e. amines having two organic substituents,
include dialkylamines, e.g. diethylamine, dipropylamine and
di-isopropylamine, dialkanolamines, e.g. diethanolamine, and
pyrrolidine. Examples of suitable tertiary amines, i.e. amines
having three organic substituents, include trialkylamines, e.g.
triethylamine, trialkanolamines, e.g. triethanolamine,
N,N-dialkylalkanolamines, e.g. N,N-dimethylethanolamine. Examples
of suitable quaternary ammonium compounds include methyl bis[ethyl
(tallowate)]-2-hydroxyethyl ammonium methyl sulphate,
dioctyldimethylammonium chloride, didecyldimethylammonium chloride,
dicocodimethylammonium chloride, cocobenzyldimethylammonium
chloride, coco(fractionated)benzyldimethylammonium chloride,
octadecyl trimethylammonium chloride, dioctadecyl dimethylammonium
chloride, dihexadecyl dimethylammonium chloride, di(hydrogenated
tallow)dimethylammonium chloride, di(hydrogenated
tallow)benzylmethylammonium chloride, di(hydrogenated tallow fatty
acids-2-hydroxyethyl ester) dimethyl ammonium chloride,
(hydrogenated tallow)benzyldimethylammonium chloride,
dioleyldimethylammonium chloride, di(ethylene
hexadecanecarboxylate)dimethylammonium chloride,
(vegetableoil)benzyldimethylammonium chloride,
(dodecyl)benzyl-dimethylammonium chloride and quaternised imidazole
derivates. Examples of suitable diamines include
aminoalkylalkanolamines, e.g. aminoethylethanolamine, piperazine
and nitrogen-substituted piperazines having one or two lower alkyl
groups of 1 to 4 carbon atoms. Example of suitable imidazoline
derivates include quaternary imidazolinium compounds, e.g. 2-(C17
and C17 unsaturated alkyl)-1-[2-(C18 and C18-unsaturated amido)
ethyl]-4,5-dihydro-1-methyl, methyl sulfates. Examples of preferred
nitrogen-containing organic compounds include methyl bis[ethyl
(tallowate)]-2-hydroxyethyl ammonium methyl sulphate,
di(hydrogenated tallow)dimethylammonium chloride, di(hydrogenated
tallow fatty acids-2-hydroxyethyl ester) dimethyl ammonium
chloride, didecyldimethylammonium chloride,
(vegetableoil)benzyl-dimethylammonium chloride and
(dodecyl)benzyl-dimethylammonium chloride.
[0022] The cellulose-reactive sizing agent can be selected from the
group consisting of hydrophobic ketene dimers, ketene multimers,
acid anhydrides, organic isocyanates and mixtures thereof,
preferably ketene dimers, ketene multimers and acid anhydrides,
most preferably ketene dimers. Suitable ketene dimers have the
general formula (I) below, wherein R.sup.1 and R.sup.2 represent
saturated or unsaturated hydrocarbon groups, usually saturated
hydrocarbons, the hydrocarbon groups suitably having from 8 to 36
carbon atoms, usually being straight or branched chain alkyl groups
having 12 to 20 carbon atoms, such as hexadecyl and octadecyl
groups. Suitable acid anhydrides can be characterized by the
general formula (II) below, wherein R.sup.3 and R.sup.4 can be
identical or different and represent saturated or unsaturated
hydrocarbon groups suitably containing from 8 to 30 carbon atoms,
or R.sup.3 and R.sup.4 together with the --C--O--C-- moiety can
form a 5 to 6 membered ring, optionally being further substituted
with hydrocarbon groups containing up to 30 carbon atoms. Examples
of acid anhydrides which are used commercially include alkyl and
alkenyl succinic anhydrides and particularly isooctadecenyl
succinic anhydride.
##STR00001##
[0023] Suitable ketene dimers, acid anhydrides and organic
isocyanates include the compounds disclosed in U.S. Pat. No.
4,522,686, which is hereby incorporated herein by reference.
[0024] The dispersions of this invention contain a dispersant or a
dispersant system comprising one or more dispersing agents and
protective colloids. The dispersing agents and protective colloids
can be selected from anionic, non-ionic, cationic and amphoteric
compounds which separately or together may function as dispersing
agent or dispersant system for the cellulose-reactive sizing agent.
The dispersions according to the invention can have contents of
cellulose-reactive sizing agents from about 0.1% by weight up to
about 30% by weight. The content of cellulose-reactive sizing agent
is suitably within the range of from 5 to 25% and preferably from 8
to 20% by weight.
[0025] The dispersing agents and protective colloids can be any of
those conventionally used in the preparation of aqueous sizing
dispersions or emulsions. They can for example be selected from
saponified rosin derivatives, alkyl sulphates, alkylaryl sulphates,
alkyl sulphonates, alkylaryl sulphonates, etc. Particularly
suitable anionic dispersing agents are alkyl sulphates and alkyl
sulphonates, e.g. sodium lauryl sulphate, as well as sodium
lignosulphonate and sodium naphthalene sulphonate. Examples of
suitable protective colloids include water-soluble
cellulose-derivatives such as hydroxyethyl- and hydroxypropyl-,
methylhydroxypropyl- and ethylhydroxyethylcellulose, methyl- and
carboxymethylcellulose, gelatin, starch, guar gum, xanthan gum,
polyvinyl alcohol, etc.. Examples of suitable non-ionic dispersing
agents can for example be selected from fatty alcohols, ethoxylated
fatty alcohols, fatty acids, alkyl phenols or fatty acid amides,
ethoxylated or non-ethoxylated glycerol esters, sorbitan esters of
fatty acids, etc.. Examples of suitable cationic dispersing agents
and protective colloids include water-soluble nitrogen-containing
epichlorohydrin resins and cationic starches, etc.. The dispersion
may also contain other additives such as preservative agents.
Suitably, the amount of dispersing agent is at least 0.5% by
weight, based on the amount of sizing agent. Normally, it is not
necessary to use more than 10% by weight.
[0026] The nitrogen-containing organic compound of the invention
and the cellulose-reactive sizing agent can be separately added to
the cellulosic suspension in any order. The nitrogen-containing
organic compound can be separately added prior to, simultaneously
with or after adding the cellulose-reactive sizing agent and
preferably prior to adding the cellulose-reactive sizing agent.
[0027] The nitrogen-containing organic compound and the aqueous
dispersion of cellulose-reactive sizing agent, herein also referred
to as sizing dispersion, can also be added to the cellulosic
suspension as a pre-mix. In this embodiment, the
nitrogen-containing organic compound and the sizing dispersion are
mixed to form a pre-mix before addition to the cellulosic
suspension. The mixing can be done by bringing into contact some
time before the addition the nitrogen-containing organic compound,
suitably an aqueous phase thereof and preferably an aqueous stream
thereof, and the sizing dispersion, preferably an aqueous stream
thereof.
[0028] The obtained aqueous phase or stream is then introduced to
the cellulosic suspension. Preferably, the contact time, i.e. the
time from mixing the nitrogen-containing organic compound and the
sizing dispersion to adding the pre-mix so formed to the cellulosic
suspension, is short. This period of time can be less than about 20
minutes, suitably less than 4 minutes and preferably less than 2
minutes.
[0029] The mixing of aqueous streams of the nitrogen-containing
organic compound and the sizing dispersion can be effected by
directing the separate streams to be mixed towards each other,
allowing them to impinge on each other and introducing the pre-mix
stream so formed into the cellulosic suspension. Suitably mixing is
carried out under turbulent flow conditions, which promote more
intensive and rapid mixing of the streams. The streams can be mixed
by means of any mixing device having at least two inlets into which
separate streams to be mixed are supplied and having at least one
outlet through which the resulting pre-mix is passed and
subsequently introduced to the cellulosic suspension. This stream
mixing embodiment is advantageous from a practical point of view
and confers operational benefits.
[0030] The nitrogen-containing organic compound and the
cellulose-reactive sizing agent can be added to the cellulosic
suspension at any position, e.g. anywhere between the machine chest
and the headbox.
[0031] The nitrogen-containing organic compound and the
cellulose-reactive sizing agent can be added to the cellulosic
suspension in amounts that can vary within wide limits, where the
dosage is mainly dependent on the quality of the pulp or paper to
be sized, the cellulose-reactive sizing agent used and the level of
sizing desired. The nitrogen-containing organic compound is
suitably added to the cellulosic suspension in an amount of from
0.005 to 0.5% by weight, preferably of from 0.01 to 0.3% by weight
and most preferably of from 0.02 to 0.1% by weight based on the dry
weight of the cellulosic suspension. The cellulose-reactive sizing
agent is suitably added to the cellulosic suspension in an amount
of from 0.01 to 1.0% by weight, preferably of from 0.05 to 0.5% by
weight based on the dry weight of the cellulosic suspension.
[0032] The term "paper", as used herein, is meant to include not
only paper but all types of cellulose-based products in sheet and
web form, including, for example, board, paperboard and
particularly liquid packaging board. The process according to the
invention can be used in the production of paper from different
types of cellulosic suspensions of cellulose-containing fibres and
the suspensions should suitably contain at least 25% by weight and
preferably at least 50% by weight of such fibres, based on dry
substance. The suspension can be based on fibres from chemical pulp
such as sulphate, sulphite and organosolv pulps, mechanical pulp
such as thermomechanical pulp, chemo-thermomechanical pulp, refiner
pulp and groundwood pulp, from both hardwood and softwood, and can
also be based on recycled fibres, optionally from de-inked pulps,
and mixtures thereof. The cellulosic suspension may optionally also
contain mineral fillers. Examples of mineral fillers of
conventional types include kaolin, china clay, titanium dioxide,
gypsum, talc and natural and synthetic calcium carbonates such as
chalk, ground marble and precipitated calcium carbonate. The pH of
the cellulosic suspension can be within the range of from about 3
to about 10. The pH is suitably above 3.5 and preferably within the
range of from 4 to 9.
[0033] Chemicals conventionally added to the cellulosic suspension
in papermaking such as retention aids, aluminium compounds, dyes,
wet-strength resins, optical brightening agents, etc., can of
course be used in conjunction with the present dispersions.
Examples of aluminium compounds include alum, aluminates and
polyaluminium compounds, e.g. polyaluminium chlorides and
sulphates. Examples of suitable retention aids include cationic
polymers, anionic inorganic materials in combination with organic
polymers, e.g. bentonite in combination with cationic polymers,
silica-based sols in combination with cationic polymers or cationic
and anionic polymers. Particularly good internal sizing can be
obtained when using the nitrogen-containing organic compound and
the cellulose-reactive sizing agent as described above in
combination with retention aids comprising cationic polymers.
Suitable cationic polymers include cationic starch, guar gum,
acrylate-based and acrylamide-based polymers, polyethyleneimine,
dicyandiamide-formaldehyde resins, polyamines, polyamidoamines and
poly(diallyldimethyl ammoniumchloride) and combinations thereof.
Cationic starch and cationic acrylamide-based polymers are
preferably used, either alone or in combination with each other or
with other materials.
[0034] The invention is further illustrated in the following
examples, which, however, are not intended to limit the same.
EXAMPLE 1
[0035] AKD sizing of liquid packaging board was performed on an
experimental paper machine which comprised a machine chest, two
separate pumping arrangements, defoamer, screen, headbox and a
wire, where the cellulosic suspension was dewatered to form a
sheet.
[0036] The nitrogen-containing organic compounds used in the
following Examples are those described in Table 1.
TABLE-US-00001 TABLE 1 Nitrogen-containing organic compound
Description Molecular weight Trade name A Di(hydrogenated 560
Arquad 2HT-75PG tallow)dimethylammonium chloride B
Didecyldimethylammonium 360 Arquad 2.10-50 chloride C
(Vegetableoil)benzyl- 410 Arquad HTB-75 dimethylammonium chloride D
(Dodecyl)benzyl- 420 Croda N-Dodecyl dimethylammonium chloride E
Quaternary imidazolinium 744 Incrosoft CFI-90 PG F polyDADMAC
350,000 Eka ATC 6340 G Di(hydrogenatedtallow fatty 702 Armosoft DEQ
acids-2-hydroxyethyl ester) dimethyl ammonium chloride
[0037] The cellulosic suspension comprised 100% bleached CTMP. Two
different nitrogen-containing organic compounds were used in the
tests: A and E. The addition of the nitrogen containing compound to
the cellulosic suspension took place after the machine chest. A
reference without addition of nitrogen-containing organic compound
was also performed. Cationic starch (Raisamyl 142) was dosed at two
points; after the first pumping arrangement (P1) 2 kg/tonne and
before the second pumping arrangement (P2) 3 kg/tonne. The AKD (Eka
DH 28HF) sizing agent was dosed before the P2 and a silica sol (Eka
NP 442) was dosed after the P2 (3 kg/tonne as received). pH at the
head box was 8.0.
[0038] Edge Wick (EW) tests with lactic acid (1%) were performed on
the final paper after 1 h and 24 h, respectively. The results are
presented in Table 2.
TABLE-US-00002 TABLE 2 1 h EW (LA 1%) 24 h EW (LA 1%) (kg/m.sup.2)
(kg/m.sup.2) AKD AKD Nitrogen-containing (2 AKD (2 AKD organic
compound kg/tonne) (3 kg/tonne) kg/tonne) (3 kg/tonne) Reference
1.29 0.96 0.68 0.56 E (0.5 kg/tonne) 0.9 0.78 0.63 0.60 A (0.5
kg/tonne) 0.83 0.67 0.6 0.55 A (1.0 kg/tonne) 0.75 0.62 0.63
0.54
[0039] As can be seen from Table 2, the tests using
nitrogen-containing organic compounds according to the present
invention showed lower EW values after 1 hour compared to
references which did not contain any nitrogen-containing organic
compound. It can be concluded that the addition of
nitrogen-containing organic compounds shorten the curing time.
After 24 hours, all samples show about the same EW values.
EXAMPLE 2
[0040] The papermaking conditions were the same as in Example 1.
Two different dosages (0.25 kg/tonne and 0.5 kg/tonne) of the
nitrogen-containing organic compounds were tested at two dosage
levels of AKD (1 kg/tonne and 1.5 kg/tonne).
[0041] Sizing performance was tested as Cobb.sub.60-value on the
paper directly after it had come off the machine, after 1 h, 3 h,
and finally after 24 h according to the standard method Tappi T441.
The results are shown in Table 3.
TABLE-US-00003 TABLE 3 Nitrogen- Nitrogen- containing containing
organic Cobb.sub.60 (g/m.sup.2) organic AKD compound Off compound
(kg/tonne) (kg/tonne) Machine 1 h 3 h 24 h Reference 1.0 0 220 127
39 20 A 1.0 0.25 68 39 26 18 B 1.0 0.25 111 47 31 21 C 1.0 0.25 42
30 25 19 D 1.0 0.25 84 41 26 21 Reference 1.5 0 41 29 23 17 A 1.5
0.25 28 24 21 17 B 1.5 0.25 35 24 21 17 C 1.5 0.25 24 22 19 17 D
1.5 0.25 28 24 21 18 A 1.0 0.5 31 26 23 20 B 1.0 0.5 42 30 24 20 C
1.0 0.5 31 26 22 20 D 1.0 0.5 58 40 26 21 A 1.5 0.5 22 20 18 17 B
1.5 0.5 26 21 19 17 C 1.5 0.5 24 19 18 17 D 1.5 0.5 27 23 20 18
[0042] Cobb.sub.60-values off machine and after 1 h of the paper
samples treated with a nitrogen-containing organic compound show
lower Cobb.sub.60-values compared to Cobb.sub.60-values of the
reference. After 24 h, all the samples have reached approximately
the same sizing degree. From the results of Table 3 it can also be
concluded that it is possible to decrease the AKD dosage when a
nitrogen-containing organic compound according to the present
invention is added to the suspension.
[0043] Tensile index (SCAN-P 67:93) was tested on the paper sheets
treated with the nitrogen-containing organic compounds and compared
with the reference in order to investigate if the
nitrogen-containing organic compounds have had a negative effect on
the paper strength. The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Nitrogen-containing Nitrogen-containing AKD
organic compound Tensile index organic compound (kg/tonne)
(kg/tonne) (Nm/g) Reference 1.0 -- 29.7 A 1.0 0.25 29.1 B 1.0 0.25
30.6 C 1.0 0.25 29.9 D 1.0 0.25 29.9 Reference 1.5 -- 30.9 A 1.5
0.25 27.3 B 1.5 0.25 28.5 C 1.5 0.25 30.0 D 1.5 0.25 30.3 A 1.0
0.50 27.9 B 1.0 0.50 29.6 C 1.0 0.50 28.1 D 1.0 0.50 30.5 A 1.5
0.50 28.3 B 1.5 0.50 30.6 C 1.5 0.50 30.3 D 1.5 0.50 30.5
[0044] The results show that the nitrogen-containing organic
compounds do not have any significant effect on the tensile
strength and therefore do not deteriorate paper/board quality.
EXAMPLE 3
[0045] In this Example, sizing performance was tested as
Cobb.sub.60-value on paper when nitrogen-containing organic
compounds were added in different addition modes. Further, sizing
performance was tested when using a nitrogen-containing organic
compound according to the present invention and polyDADMAC
polymer.
[0046] The cellulosic suspension contained 80% hardwood and 20%
softwood and had a fiber concentration of 0.5%. No filler was
added. The conductivity was 0.3 mS/cm and pH was about 8. Hand
sheets were prepared according to the standard method SCAN-C26:76
and sizing property was measured as Cobb.sub.60 value according to
the standard method Tappi T441.
[0047] A first retention system was used comprising 0.75 kg/tonne
cationic polyacrylamide (Eka PL 1510) and 1 kg/tonne of silica sol
(Eka NP 442), calculated as dry substances on dry cellulosic
suspension. The results are presented in Table 5. A second
retention system was used comprising 5 kg/tonne of cationic potato
starch (Perlbond 980) and 1 kg/tonne of silica sol (Eka NP 442),
calculated as dry substances on dry cellulosic suspension. The
results are presented in Table 6.
[0048] The dosage of the cationic polyacrylamide (EKA PL 1510) was
reduced to 0.5 kg/tonne in the cases where polyDADMAC (F) was added
to the paper fiber suspension.
[0049] The sizing agent AKD (Eka DR 28 HF) was added in an amount
of 0.45 kg/tonne and the nitrogen-containing organic compound,
Arquad HTB-75 (C), according to the invention was either added:
[0050] a) 2 minutes before AKD,
[0051] b) premixed with AKD,
[0052] c) simultaneously with AKD
[0053] d) after AKD.
[0054] The sizing results obtained by the addition of 0 kg/tonne,
0.25 kg/tonne and 0.5 kg/tonne of the nitrogen-containing organic
compound (C) are shown in Tables 5 and 6, respectively. The results
can be compared with the results obtained by the absence of the
nitrogen-containing organic compound or by addition of the polymer
(F) instead of the nitrogen-containing organic compound according
to the invention.
TABLE-US-00005 TABLE 5 Cobb.sub.60 (g/m.sup.2) F C Addition mode
Reference (0.25 kg/tonne) (0.25 kg/tonne) no addition 63 a)
addition before AKD 230 36 b) premixed with AKD 33 c) addition
simultaneously 38 32 with AKD d) addition after AKD 31
TABLE-US-00006 TABLE 6 Cobb.sub.60 (g/m.sup.2) F C Addition mode
Reference (0.5 kg/tonne) (0.5 kg/tonne) no addition 98 a) addition
before AKD 251 30 b) premixed with AKD 31 c) addition
simultaneously 33 31 with AKD d) addition after AKD 31
EXAMPLE 4
[0055] In this Example, liquid packaging board was prepared on an
experimental paper machine as described in Example 1 and the sizing
performance was tested as Cobb.sub.60-value according to the
standard method Tappi T441. The cellulosic suspension contained 80%
hardwood (40% eucalyptus and 40% birch) and 20% softwood and had a
fiber concentration of 1.5%. No filler was added. The pH was 7.1. A
retention system was used comprising 0.375 kg/tonne cationic
polyacrylamide (Eka PL 1510) and 0.15 kg/tonne silica sol (Eka NP
442), calculated as dry substances on dry cellulosic suspension. A
nitrogen-containing organic compound, Arquad HTB-75 (C) or Armosoft
DEQ (G), according to the invention was added before the sizing
agent AKD (Eka DR 28 HF). In order to investigate the impact of
dosing order on the sizing performance, Armosoft DEQ (G) was also
added after the addition of the AKD. The sizing results are
presented in Table Nos. 7 and 8, respectively. The results can be
compared with the results obtained by the absence of the
nitrogen-containing organic compound.
TABLE-US-00007 TABLE 7 Nitrogen- Nitrogen- containing containing
organic Cobb.sub.60 (g/m.sup.2) organic compound AKD Off 10 min.
compound kg/t kg/t machine 1 h 3 h 24 h 110.degree. C. -- 0 0.5 127
127 102 28 28 -- 0 0.75 105 98 46 26 26 -- 0 1.0 97 72 48 25 25 C
0.25 0.5 127 93 53 31 29 C 0.25 0.75 76 46 30 24 26 C 0.25 1.0 46
35 28 23 23 C 0.5 0.5 83 56 42 38 45 C 0.5 0.75 49 29 28 24 28 C
0.5 1.0 31 27 24 22 24 G 0.25 0.5 103 76 38 27 25 G 0.25 0.75 45 36
36 25 26 G 0.25 1.0 41 35 27 25 23 G 0.5 0.5 63 35 29 28 28 G 0.5
0.75 38 29 25 24 25 G 0.5 1.0 32 25 27 22 24
[0056] It can be seen that the nitrogen-containing organic
compounds according to the invention have a positive effect on the
initial sizing of AKD. It is possible to reach low
Cobb.sub.60-values already directly off machine. The final sizing
degree is not affected by the addition of the nitrogen-containing
organic compound.
TABLE-US-00008 TABLE 8 Nitrogen- Nitrogen- containing containing
organic Cobb.sub.60 (g/m.sup.2) organic compound AKD Off 10 min.
compound kg/t kg/t machine 1 h 3 h 24 h 110.degree. C. -- 0 0.5 122
116 96 27 24 -- 0 0.75 96 77 41 24 21 -- 0 1.0 78 55 35 23 21 G 0.5
0.5 109 80 38 27 23 G 0.5 0.75 60 36 30 23 21 G 0.5 1.0 37 31 30 23
21
[0057] In this example it can be seen that it is possible to add
the nitrogen-containing organic compound before or after the
addition of AKD.
EXAMPLE 5
[0058] In this Example, liquid packaging board was prepared on an
experimental paper machine as described in Example 1 and the sizing
performance was tested as Cobb.sub.60-value according to the
standard method Tappi T441. The cellulosic suspension comprised
100% bleached CTMP, which had a fiber concentration of 1.35%. No
filler was added. The pH was 5.6 and the conductivity was 219
.mu.S/cm. A nitrogen-containing organic compound, Arquad HTB-75 (C)
or Armosoft DEQ (G), was used in the tests. The addition of the
nitrogen containing compound to the cellulosic suspension took
place after the machine chest. A reference without addition of a
nitrogen-containing organic compound was also performed. The AKD
(Eka DH 28HF) sizing agent was added before the second pumping
arrangement (P2). Cationic starch (Raisamyl 142) was added before
P2 (5 kg/tonne) and a silica sol (Eka NP 442) was added after the
P2 (0.15 kg/tonne), calculated as dry substances on dry cellulosic
suspension. The nitrogen-containing organic compound, Arquad HTB-75
(C) or Armosoft DEQ (G), according to the invention was added
before the sizing agent AKD (Eka DR 28 HF).
TABLE-US-00009 TABLE 9 Nitrogen- Nitrogen- containing containing
organic Cobb.sub.60 (g/m.sup.2) organic compound AKD Off 10 min.
compound kg/t kg/t machine 1 h 3 h 24 h 110.degree. C. -- 0 0.75
338 306 280 33 25 -- 0 1.0 294 286 270 33 24 -- 0 1.25 261 227 205
29 22 C 0.25 0.75 227 173 64 26 21 C 0.25 1.0 87 54 33 23 23 C 0.25
1.25 64 38 31 21 21 C 0.5 0.75 121 71 46 25 26 C 0.5 1.0 39 30 30
21 24 C 0.5 1.25 30 28 23 20 22 G 0.25 0.75 249 225 92 28 25 G 0.25
1.0 209 177 101 27 26 G 0.25 1.25 76 42 32 23 22 G 0.5 0.75 139 58
56 26 24 G 0.5 1.0 50 33 33 23 19 G 0.5 1.25 36 28 26 23 20
[0059] It can be seen that the nitrogen-containing organic
compounds according to the invention have a positive effect on the
initial sizing of AKD. It is possible to reach low
Cobb.sub.60-values already after 1 h. The final sizing degree is
not affected by the addition of the nitrogen-containing organic
compound. The tensile index is not decreased by the addition of the
nitrogen-containing organic compounds.
[0060] The nitrogen-containing organic compounds according to the
invention function together with AKD in amounts of from about 0.05
to about 5 kg/tonne calculated on dry pulp, preferably from about
0.1 to about 3 kg/tonne calculated on dry pulp and most preferably
from about 0.2 to about 1 kg/tonne calculated on dry pulp.
* * * * *