Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1
Composition
The invention reiates to a composition used for enhancing softness in paper
products. The invention also relates to a papermaking process in which the
composition
is added to the cellulosic suspension or applied to a wet or dry paper web.
The
composition comprises an oil, wax or fat; at least one cationic, amphoteric or
non-ionic
polymer; an anionic compound selected from anionic surfactants and anionic
microparticles; and one or more non-ionic surfactant(s).
Background
Paper webs or sheets, usually called tissue or- paper tissue webs, are
commonly
used in paper towels, napkins, facial and toilet tissues. The important
characteristics for
such papers are softness, absorbency and strength. There is an ongoing work to
improve
each of these characteristics without seriously affecting the others.
Conventionally pressed tissue paper and methods for making such paper are
well known in the art. Such paper is typically made by draining and forming a
cellulosic
suspension on a wire. The cellulosic suspension is usually contained in the
headbox
before being deposited on a Fourdrinier wire to form a paper web. The paper
web is then
typically dewatered by vacuum dewatering and further dried by pressing
operations
wherein the web is subjected to pressure deveioped by opposing mechanical
members,
for example cylindrical rolls or an extended nip press. The dewatered web is
then further
pressed and dried by a steam drum apparatus known in the art as a Yankee
cylinder.
Conventional fluff and methods for making such paper are well known in the
art.
Such paper is typically made by making a paper sheet on a Fourdrinier wire and
subsequently pressing and drying the paper sheet into bales or rolls. The dry
paper is
then defiberized using a hammermill or a pin defiberizer to form fluff.
Typical products
made from fluff are diapers and feminine hygiene products. Fluff can also be
used to
produce air laid paper products.
Softness is a tactile sensation perceived by the consumer holding a particular
product, rubbing it across the skin or crumpling it within the hand. Softness
of a sheet can
be achieved by mechanical means. For example, the sheet can be calendered to
flatten
the crests formed when creping the sheet. The sheet can also be frictionally
treated in
order to eliminate any roughness. However, these approaches are often
insufficient.
One way to make the paper softer is to add a softening compound to the
cellulosic suspension. The softening compound interferes with the natural
fibre-to-fibre
bonding that occurs during sheet formation in papermaking processes. This
reduction of
bonding leads to a softer, or less harsh, sheet of paper.
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WO 98/07927 describes the production of soft absorbent paper products using a
softener. The softener comprises a quaternary ammonium surfactant, a non-ionic
surfactant as well as strength additives. The softening agent is added to the
cellulosic
suspension before the paper web is formed.
A softening compound can also be applied to a dry or wet paper web e.g. by
means of spraying. If the paper web is dry, the softening compound can also be
printed
on the paper.
US 5,389,204 describes a process for making soft tissue paper with functional-
polysiloxane softener. The softener comprises a functional-polysiloxane, an
emulsifier
surfactant and surfactants which are noncationic. The softener is transferred
to the dry
paper web through a heater transfer surface. The softener is then pressed on
the dry
paper web.
WO 97/30217 describes a composition used as a lotion to increase the softness
of absorbent paper. The composition comprises an emollient which is preferably
a fatty
alcohol or a waxy ester. The composition also comprises a quaternary ammonium
surfactant as well as one or more non-ionic or amphoteric emulsifiers.
Most softening compounds, either added to the cellulosic suspension or applied
to the paper web, contain quaternary ammonium surfactants. Since producers and
consumers experience a growing environmental concern, quaternary ammonium
surfactants are not always accepted. The quaternary ammonium surfactants are
generally toxic to aquatic organisms and are generally considered undesired
chemicals.
It is an object of the invention to provide a composition for enhancing
softness of
a paper product.
It is a further object of the invention to provide a composition substantially
free
from quaternary ammonium surfactants.
Yet another object of the invention is to provide one single composition
suitable
for addition to the cellulosic suspension and applied to a wet or dry paper
web, rather
than several different compositions as described in the prior art.
Yet a further object of the invention is to provide a composition that has a
high
tolerance towards anionic carryover from preceding production stages. Standard
formulations can thus be neutralised in the wet end when small amounts of
detrimental
substances are released from the preceding production stages.
It is also an object of the invention to provide a composition that, when
added to
the cellulosic suspension, will impart low burst strength, high wetting rate
as well as low
defiberization energy to the paper to be produced.
It is also a further object of the invention to provide a composition that,
when
added to the cellulosic suspension, will impart a low knot content to the
product.
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The Invention
The invention relates to a composition used for enhancing softness in paper
products, preferably products prepared from tissue or fluff. The composition
can be
applied at various stages in the papermaking process. The composition can for
instance
be added in the wet end to the cellulosic suspension. A composition added to
the
cellulosic suspension to enhance softness of the product is called a debonder.
The
composition can also be applied to the paper web to enhance the surface feel
of the
product, e.g. the softness. If the composition is applied to a wet paper web,
the
composition is called a softener. If the composition is applied to a dry paper
web, the
composition is called a lotion.
The composition of the invention comprises
(i) an oil, fat or wax
(ii) at least one non-ionic surfactant
(iii) at least one anionic compound selected from anionic microparticies
and anionic surfactants
(iv) at least one polymer which is cationic, non-ionic or amphoteric,
wherein the non-ionic surfactant is added in an amount of about 60 to about
1000 parts
by weight per 100 parts by weight of the polymer.
According to one embodiment, the composition is substantially free from
quaternary ammonium surfactants. By "substantially free" is meant that less
than 5 wt%
of the composition is comprised of quaternary ammonium surfactants, such as
less than
I wt%, or less than 0.5 wt%.
Any oil, fat or wax, functioning as an emollient, can be used according to the
invention. Suitable oils are refined and/or hydrogenated grade oils, such as
vegetable oils
like grape oil, olive oil, coconut oil, rape seed oil, sunflower oil, and palm
oil, most
preferably coconut oil. Other oils that can be used according to the invention
are mineral
oils and silicon oil.
To retain the oil, fat or wax in a produced paper, a polymer functioning as a
retention aid, is required. Suitable polymers for use as a retention agent or
part of a
retention system may be highly charged. According to one embodiment, the
polymer is a
cationic polymer. The polymers can be derived from natural or synthetic
sources and they
can be linear, branched or cross-linked, e.g. in the form of microparticies.
Preferably, the
polymer is water-soluble or water-dispersible.
Examples of suitable natural cationic polymers include cationic
polysaccharides,
e.g. starches, guar gums, cellulose derivatives, chitins, chitosans, glycans,
galactans,
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glucans, xanthan gums, pectins, mannans, dextrins, preferably starches and
guar gums.
Suitable starches include potato, corn, wheat, tapioca, rice, waxy maize,
barley, etc.
Cationic synthetic organic polymers such as cationic chain-growth polymers may
also be
used, e.g. cationic vinyl addition polymers like acrylate-, acrylamide-,
vinylamine-,
vinylamide- and allylamine-based polymers, for example homo- and copolymers
based
on diallyidialkyl ammonium halide, e.g. diallyldimethyl ammonium chloride, as
well as
(meth)acrylamides and (meth)acrylates. Further polymers include cationic step-
growth
polymers, e.g. cationic polyamidoamines, polyethylene imines, polyamines, e.g.
dimethylamine-epichlorhydrin copolymers; and polyurethanes. Further examples
of
suitable cationic organic polymers include those disclosed in WO 02/12626.
According to one embodiment, the polymer is selected from the group consisting
of polydiallyldimethyl ammonium chloride, polyamines, cationic starch,
amphoteric starch,
and polyamidoamine-epichlorohydrin (PAAE), polyethylene imines and
polyvinylamines.
The term "step-growth polymer", as used herein, refers to a polymer obtained
by
step-growth polymerization, also being referred to as step-reaction polymer
and step-
reaction polymerization respectively. The term "chain-growth polymer", as used
herein,
refers to a polymer obtained by chain-growth polymerization, also being
referred to as
chain reaction polymer and chain reaction polymerization respectively.
The polymer according to the invention can have a molecular weight of from
about 10000 to about 10000000, such as from about 15000 to about 5000000, or
from
about 40000 to about 1000000.
According to one embodiment, an anionic microparticle is comprised in the
composition. Examples of suitable anionic microparticles include anionic
silica
microparticles, such as anionic colloidal silica particles, and smectite
clays, most
preferably anionic hydrophobically modified colloidal silica particles. The
anionic
microparticies preferably have a specific surface area from about 40 to about
900, such
as from about.150 to about 600, or from about 250 to about 400 m2/g.
Colloidal silica particles may be derived from e.g. precipitated silica, micro
silica
(silica fume), pyrogenic silica (fumed silica) or silica gels with sufficient
purity,
conventional sodium silicate, and mixtures thereof.
Colloidal silica particles according to the invention may be modified and can
contain other elements such as amines, aluminium and/or boron, which can be
present in
the particles and/or the continuous phase. Boron-modified silica sols are
described in e.g.
US 2,630,410. The aluminium modified silica particles suitably have an A1203
content of
from about 0.05 to about 3 wt%, such as from about 0.1 to about 2 wt%. The
procedure
of preparing an aluminium modified silica sol is further described in e.g.
"The Chemistry
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of Silica", by.Iler, K. Ralph, pages 407-409, John Wiley & Sons (1979) and in
US 5 368
833.
The colloidal silica particles suitably have an average particle diameter
ranging
from about 2 to about 150, such as from about 3 to about 50, or from about 5
to about 40
5 nm. Suitably, the colloidal silica particles have a specific surface area
from about 20 to
about 1500, such as from about 50 to about 900, or from about 70 to about 600
m2/g.
Anionic surfactants that can be used according to the invention are generally
anionic surfactants with hydrophobic "tails" having from about 6 to about 30
carbon
atoms. Examples of preferred anionic surfactants are saponified fatty acids,
alkyl(aryl)sulphonates, sulphate esters, phosphate esters,
alkyl(aryl)phosphates,
alkyl(aryl) phosphonates, fatty acids, naphthalene sulphonate (NAS),
formaldehyde
polycondensates, polystyrene sulphonates, hydrophobe-modified NAS. Most
preferred
are saponified fatty acids, alkyl(aryl)sulphonates, sulphate esters, phosphate
esters,
alkyl(aryl)phosphates, alkyl(aryl) phosphonates, and mixtures thereof.
According to one embodiment, the anionic compound is an anionic surfactant.
Non-ionic surfactants that can be used according to the invention include
generally ethoxylated or propoxylated fatty acids or fatty alcohols. The
ethoxylated fatty
acids and fatty alcohols have preferably been ethoxylated with from about 1 to
about 30
ethylene oxide (EO), or from about 4 to about 25 EO. The ethoxylated fatty
acids and
fatty alcohols may have from about 6 to about 30 carbon atoms, or from about 6
to about
22 carbon atoms. The propoxylated fatty acids and fatty alcohols may have been
propoxylated with from about 1 to about 30 propylene oxide (PO), or from about
1 to
about 8 PO. The propoxylated fatty acids and fatty alcohols preferably have
from about 6
to about 30 carbon atoms, such as from about 6 to about 22 carbon atoms. It is
also
possible to use carbon dioxide instead of propylene oxide.
The polymer is suitably present in the composition in an amount of from about
I
to about 50, such as from about 5 to about 40, or from about 10 to about 30
wt% based
on the dry weight of the composition.
The oil, fat or wax is suitably present in the composition in an amount of
from
about I to about 95, such as from about 30 to about 80, or from about 35 to
about 75
wt% based on the dry weight of the composition.
The anionic compound is suitably present in the composition in an amount of
from about 0.1 to about 10, such as from about 0.5 to about 4, or from about
0.6 to about
2 wt% based on the dry weight of the composition.
According to one embodiment, the non-ionic surfactant is present in an amount
of from about 70 to about 800, or from about 80 to about 600, or from about
100 to about
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500, or from about 150 to about 400 parts by weight per 100 parts by weight of
the
polymer.
The composition can be prepared by first mixing the oil, fat or wax together
with
the anionic and non-ionic surFactants to provide an emollient-surfactant
blend. The
emollient-surfactant blend may be heated to about 25 to about 70 C. An aqueous
solution
containing the polymer is suitably prepared in which solution the polymer
content
constitutes from about 0.1 to about 50, e.g. from about 0.5 to about 25 wt%.
The aqueous
solution may be heated to from about 25 to about 70 C. The emollient-
surfactant blend
may then be emulsified in the aqueous solution containing the polymer by a
static mixer,
an ultra-turrax high shear device or a homogenizer. The product emulsion can
then be
cooled to room temperature. The cooling can for example be performed by using
a heat
exchanger.
According to one embodiment, the emollient surfactant mix is emulsified into
the
aqueous solution containing the polymer by means of a static mixer.
The composition can be produced in advance and then be delivered as one
product to the paper mill. The composition can also be prepared on site at the
paper mill
from the different components.
It is also possible to add additional components to the composition. To avoid
deterioration of the composition a preserving agent may be added. Several
cosmetic
additives can also be included, for example antioxidants, e.g. tocopherol, and
aloe vera.
The invention also relates to a process for production of paper comprising
adding the composition as described herein to a cellulosic suspension wherein
said
process further comprises draining the cellulosic suspension on a wire to form
a paper
web.
According to one embodiment, the composition may be added in an amount of
from about 0.1 to about 15 kg/ton dry cellulosic fibres.
When the debonder is used for manufacturing fluff, the composition is usually
added to a cellulosic suspension in an amount of from about 0.1 to about 15,
such as
from about 0.3 to about 10 kg/ton dry cellulosic fibres.
When the debonder is used for manufacturing tissue, the composition is usually
added to a cellulosic suspension in an amount of from about 0.1 to about 15,
such as
from about 0.5 to about 4 kg/ton dry cellulosic fibres.
When used as a debonder in this process, the composition, as already stated
herein, is added to the cellulosic suspension before the paper web is formed.
Use of
debonders is very common when making fluff and tissue. The debonder will
interfere with
the natural fibre-to-fibre bonds so that the strength is reduced. By reducing
the strength
the softness of the fluff and the tissue products are increased. According to
one
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embodiment, the components of the composition can be added separately to the
cellulosic suspension. Preferably, an emulsion of the oil, fat or wax and the
anionic and
non-ionic surfactant can be added as a pre-blend and a polymer, e.g. in an
aqueous
solution, can be added as a separate component to the cellulosic suspension.
According to one embodiment, when the components are added separately, the
amount of each component added to the cellulosic suspension corresponds to the
amount of each component in the composition as described herein.
According to one embodiment, when manufacturing fluff, the polymer can be
added to a cellulosic suspension in an amount from about 0.01 to about 6
kg/ton dry
10= cellulosic fibres. According to one embodiment, when manufacturing fluff,
the polymer
can be- added to a cellulosic suspension in an amount from about 0.025 to
about 3.5
kg/ton dry cellulosic fibres. According to one embodiment, when manufacturing
fluff, the
polymer can be added to a cellulosic suspension in an amount from about 0.05
to about
2.5 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing fluff, the oil, wax or fat can
be added to a cellulosic suspension in an amount from about 0.001 to about 14
kg/ton dry
cellulosic fibres. According to one embodiment, when manufacturing fluff, the
oil, wax or
fat can be added to a cellulosic suspension in an amount from about 0.03 to
about 12
kg/ton dry cellulosic fibres. According to one embodiment, when manufacturing
fluff, the
oil, wax or fat can be added to a cellulosic suspension in an amount from
about 0.035 to
about 11 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing fluff, the anionic compound
can be added to a cellulosic suspension in an amount from about 0.001 to about
1.5
kg/ton dry cellulosic fibres. According to one embodiment, when manufacturing
fluff, the
anionic compound can be added to a cellulosic suspension in an amount from
about
0.003 to about 0.6 kg/ton dry cellulosic fibres. According to one embodiment,
when
manufacturing fluff, the anionic compound can be added to a cellulosic
suspension in an
amount from about 0.004 to about 0.3 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing fluff, the non-ionic
surfactant
is suitably added to the cellulosic suspension in an amount of from about 70
to about 800,
such as from about 80 to about 600, or from about 100 to about 500, or from
about 150 to
about 400 parts by weight per 100 parts by weight of the polymer.
According to one embodiment, when manufacturing fluff the oil, wax or fat is
added in an amount of about 0.001 to about 14 kg/ton dry cellulosic fibres,
the anionic
compound is added in an amount of about 0.001 to about 1.5 kg/ton dry
cellulosic fibres
and the polymer is added in an amount of about 0.01 to about 6 kg/ton dry
cellulosic
fibres.
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According to one embodiment, when manufacturing tissue, the polymer can be
added to a cellulosic suspension in an amount from about 0.01 to about 8
kg/ton dry
cellulosic fibres. According to one embodiment, when manufacturing tissue, the
polymer
can be added to a cellulosic suspension in an amount from about 0.03 to about
6 kg/ton
dry cellulosic fibres. According to one embodiment, when manufacturing tissue,
the
polymer can be added to a cellulosic suspension in an amount from about 0.035
to about
5.5 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing tissue, the oil, wax or fat
can
be added to a cellulosic suspension in an amount from about 0.001 to about 10
kg/ton dry
cellulosic fibres. According to one embodiment, when manufacturing tissue, the
oil, wax
or fat can be added to a cellulosic suspension in an amount from about 0.03 to
about 8
kg/ton dry cellulosic fibres. According to one embodiment, when manufacturing
tissue,
the oil, wax or fat can be added to a cellulosic suspension in an amount from
about 0.035
to about 7.5 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing tissue, the anionic
compound can be added to a cellulosic suspension in an amount from about 0.001
to
about 1 kg/ton dry cellulosic fibres. According to one embodiment, when
manufacturing
tissue, the anionic compound can be added to a cellulosic suspension in an
amount from
about 0.003 to about 0.4 kg/ton dry cellulosic fibres. According to one
embodiment, when
manufacturing tissue, the anionic compound can be added to a cellulosic
suspension in
an amount from about 0.004 to about 0.2 kg/ton dry cellulosic fibres.
According to one embodiment, when manufacturing tissue, the non-ionic
surfactant is suitably added to the cellulosic suspension in an amoun.t of
from about 70 to
about 800, such as from about 80 to about 600, or from about 100 to about 500,
or from
about 150 to about 400 parts by weight per 100 parts by weight of the polymer.
To evaluate the performance of the debonder, burst strength, defiberization
energy and wetting rate can be measured. Low burst strength and low
defiberization
energy shows that the fibre-to-fibre bonds are weak, which in turn facilitates
the
production of tissue with enhanced softness. The wetting rate indicates that
the finished
product will have good absorption properties.
Also, when fluff is used in air-laid applications, it is important to minimise
the
number of knots. The knots can be described as clusters of fibres. A high
number of
knots can lead to poor formation and runnability in the air-laid process.
When the composition is applied to either a wet or dry paper web, the surface
feel can be improved. Surface feel can be described as those surface
properties which
are tactile sensations perceived by the consumer. Surface feel can be
evaluated by
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people in panel tests. Examples of such properties are softness, slipperiness
and
smoothness. According to one embodiment, the composition is added to the sheet
as one
single addition. According to another embodiment, the polymer can be added to
the
cellulosic suspension prior to the formation of the web, whereas the oil, fat
or wax; the
anionic compound; and the non-ionic surfactant are added to the wet or dry
paper web.
The invention also relates to a process for production of paper comprising
applying the composition as described herein to a wet paper web. When the
composition
is used as a softener in the papermaking process, the composition is usually
sprayed
onto the wet paper web after the press section but before the Yankee cylinder.
By using
the composition as a softener, it is possible to obtain a paper with a high
surface softness
with minimal decrease in strength.
According to one embodiment, when the composition is used as a softener in the
manufacturing of tissue paper, the composition is usually added in an amount
of from
about 0.1 to about 10, preferably from about 0.3 to about 4 kg/ton dry
cellulosic fibres.
The invention also relates to a process for production of paper comprising
applying the composition as described herein to a dry paper web.
When the composition is used as a lotion in the above process, it is usually
either sprayed or printed on a dry paper web. This is usually done in the
converting
process in which the final tissue product is formed. The lotion is suitably
present as drops
on the paper web surface and is not bonded to the fibres in the same way as a
softener.
The lotion modifies the surface properties of the tissue, but the lotion is
also added for
cosmetic reasons since the lotion can be released from the paper and
transported to the
consumer.
According to one embodiment, the dry paper web has a dry content of at least
about 50, such as at least about 65, or at least about 80 wt%.
According to one embodiment, when the composition is used as a lotion for
manufacturing tissue, the composition is usually added in the amount of from
about 0.1 to
about 70, such as from about 5 to about 50 kg/ton dry cellulosic fibres.
The cellulosic fibres utilized by the present invention will normally include
fibres
derived from wood pulp, which includes chemical pulp such as Kraft, sulphite
and
sulphate pulps, as well as mechanical pulps such as ground wood,
thermomechanical
pulp and chemical modified thermomechanical pulp. Recycled fibres may also be
used.
The recycled fibres can contain all the above mentioned pulps in addition to
fillers,
printing inks etc. Chemical pulps, however, are preferred since they impart a
superior
tactile of softness to tissue sheets made from it. The utilization of recycled
fibres for
making tissue often includes a process step known as deinking to remove as
much as
possible of the printing ink from the fibre slurry and most of the filler
material to get an
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acceptable brightness and paper machine runnability of the recycled fibre
slurry. The
deinking process often includes addition of anionic substances such as
saponified fatty
acids and water glass to the fibre slurry. These substances are sometimes
carried over to
the paper machine and since these substances are anionic they can inactivate
cationic
5 chemicals added to the stock. These substances are called anionic
detrimental
substances or "anionic trash".
According to one embodiment, further components may be added to the
cellulosic suspension used to make tissue or fluff. Such additives can for
example be wet
strength agents, dry strength agents, and wetting agents as well as other
components
10 usually used in the production process. According to one embodiment, an
additional
polymer being either cationic, non-ionic or amphoteric, can be added to the
cellulosic
suspension. Suitably the polymer is either a natural polymer, for example
starch, or a
synthetic polymer.
According to one embodiment, an anionic polymer is added to the cellulosic
suspension, such anionic polymers can include anionic step-growth polymers,
chain-
growth polymers, polysaccharides, naturally occurring aromatic polymers and
modifications thereof.
The invention is further illustrated by the following examples but the
invention is
not intended to be limited thereby.
Example I
Compositions according to the invention were prepared by first mixing coconut
oil with a parasubstituted alkyl benzylsulphonic acid (-C12) (anionic
surfactant) and with
an unsaturated fatty alcohol with 16 to 18 carbon atoms being ethoxylated with
5 EO
(non-ionic surfactant). The contents of the components were 50 wt% oil, 25 wt%
anionic
surfactant and 25 wt% non-ionic surfactant. The oil-surfactant blend was then
heated to
50 C. An aqueous polymer solution was prepared. The concentration of the
polymer in
the aqueous solution was between I to 4 wt%. The polymer concentration for
each
composition is specified below. The aqueous polymer solution was heated
separately to
50 C. The oil-surfactant blend was then emulsified in the aqueous polymer
solution in a
high shear ultra-turrax. The composition was then cooled to room temperature
in a water
bath. The weight ratio of the oil-surfactant blend to the aqueous solution was
15:85.
The polymers and the concentrations thereof in the aqueous solutions used
when preparing compositions C1-C6 are listed below:
Cl: 1 wt% Poly-DADMAC (SNF No. FL45DL)
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C2: 3.4wt% Poly-DADMAC (SNF No. FL45DL)
C3: 4 wt% Poly-DADMAC (SNF No. FL45DL)
C4: I wt% Poly-DADMAC (SNF No. FL45C)
C5: 4 wt% Poly-DADMAC (SNF No. FL45C)
C6: I wt% Polyamine
For comparison, debonder compositions marketed under the name Berocell were
used.
The content of the two debonder compositions Ref. 1 and Ref. 2 is shown below.
1o Ref. 1: Berocell-589, hydrogenated tallow benzyl dimethyl ammonium
chloride; fatty
alcohol, C16-18 unsaturated ethoxylated with 5 EO
Ref.2: Beroceli-509, dihydrogenated tallow dimethyl ammonium chloride; fatty
alcohol,
C16-C20 unsaturated ethoxylated with 6 EO; fatty acid C12-C18, propoxylated
with 6P0
The dry paper sheets were prepared by mixing 15 grams of chemical pine
sulphate pulp with either water or contaminated white water up to 750 ml. The
composition was added to the pulp suspension followed by 10 minutes of
agitation.
Thereafter, a sheet was prepared in a standard PFI-sheetformer (A4 sheets).
The sheets
were then pressed, dried and conditioned according to the standardised method
SCAN
C26:76.
Example 2
The compositions C2 and C5 according to example I were compared to Ref. I
(Berocell-589) as described in example 1. The compositions were added to the
cellulosic
suspension in an amount of 3.0 kg/ton based on dry cellulosic fibres.
Dry paper sheets were then prepared as described in example 1. The paper
sheets were cut into stripes and were then defiberized with the help of a pin-
defiberizer.
The pin-defiberizer is connected to an energy meter which makes it possible to
measure
the energy consumption per kg paper, the defiberization energy. The results
are shown in
table 1.
Table I
Defiberization Energy (kJ/kg)
Composition Tap water White water
C3 56 74
C5 50 69
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12
L Ref. 1 61 88
A lower defiberization energy will impart a higher degree of softness to the
product. In table 1, it is clearly shown that the compositions according to
the invention, C3
and C5, impart lower defiberization energy, which indicates enhanced softness
compared
to the composition according to prior art, Ref. 1.
Example 3
Compositions Cl, C3, C4, C5 and C6 according to example I were compared to
Ref. I of example 1. The compositions were added to the cellulosic suspension
in an
1o amount of 3.0 kg/ton based on dry cellulosic fibres.
Dry paper sheets were then prepared according to example 1. The wetting rate
was measured on the dry paper sheets according to the standardized method SCAN-
C33:80. The results can be seen in table 2.
Table 2
Composition Wetting rate
(s/3g pulp)
C1 3.8
C3 4.1
C4 4.0
C5 4.3
C6 3.9
Ref. 1 5.6
A low wetting rate is advantageous for both tissue and fluff products. In
table 2, it
is clearly shown that the compositions according to the invention, Cl, C3, C4,
C5, and
C6, impart a= lower wetting rate to a produced paper compared to the
composition
according to prior art, Ref. 1.
Example 4
The composition C2 according to example I was compared to Ref. 2 of example
1. The amount of the composition added to the cellulosic composition varied
between 0.5
to 4.0 kg/ton based on dry cellulosic fibres.
Dry paper sheets were prepared from the cellulosic suspension as described in
example 1. The burst strength was measured according to the standardized
method ISO
2758-2001. The results can be seen in table 3.
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Table 3
Burst Strength (kPa % vs. reference)
Amount added kg/ton paper C2 Ref. 2
0.5 77 91
1.0 65 75
1.5 55 63
2.0 45 58
2.5 40 50
3.0 37 49
3.5 32 45
4.0 30 43
A low burst strength will impart softness to the product. In table 3, it is
clearly
shown that the composition, C2, according to the invention, has a lower burst
strength for
various added amounts of the composition, compared to the composition
according to
prior art, Ref. 2.
Example 5
The composition C2 according to example 1 was compared to Ref. 2 of example
1. The amount of composition added to the cellulosic suspension varied between
I to 2
kg/ton based on dry cellulosic fibres.
The knot content was measured using the standardised method SCAN-CM 37.
The results can be seen in table 4.
Table 4
Amount added Knots %
kg/ton dry paper
C2 1 3.3
C2 2 1.1
Ref. 1 1 4.2
Ref. 1 2 1.5
A high number of knots can lead to poor runnability and formation. Therefore a
low knot content is advantageous. In table 4, it is clearly shown that the
composition
according to the invention, C2, has a lower number of knots compared to Ref.
1.
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Example 6
An oil-surfactant blend was prepared by first mixing coconut oil with an
anionic
surfactant, alkyl benzylsulfonic acid (-C12), and two non-ionic surfactants,
(1) castor oil
ethoxylated with 15 EO and (2) an unsaturated fatty alcohol C16-C18
ethoxylated with 5
EO. The oil-surfactant blend was then emulsified in water to form an oil
emulsion. To 100
ml of water 0.3 g of the oil-surfactant blend was used. An aqueous polymer
solution
containing polyDADMAC was prepared with a polymer concentration of 0.08 wt%.
The dry paper sheets were prepared by mixing 15 grams of chemical pine
sulphate pulp with water up to 750 ml. The oil emulsion was added to the pulp
suspension. The suspension was then agitated for 8 minutes. Then the polymer
solution
was added whereupon the suspension was agitated for 2 minutes. After that, a
sheet was
prepared in a standard PFI-sheetformer (A4 sheets). The sheets were then
pressed,
dried and conditioned according to the standardised method SCAN C26:76. The
amounts
by weight of each component added in each trial are given in table 5.
Table 5
Composition Non-ionic Non-ionic Anionic
No. Coconut oil surfactant (1) surfactant (2) surfactant Polymer
1 9.2 0.40 0.30 0.1 2.67
2 8.7 0.65 0.55 0.1 2.67
3 8.1 0.95 0.85 0.1 2.67
4 7.6 1.2 1.1 0.1 2.67
5 5.0 2.45 2.45 0.1 2.27
The ratio of non-ionic surfactants to polymer has been calculated as parts by
weight non-
ionic surfactants per 100 parts by weight polymer. The defiberization energy
was
measured in accordance with example 2. The added amount of the composition was
1
kg/ton and 3 kg/ton dry cellulosic fibres. The results are given in table 6.
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Table 6
Composition parts non-ionic surfactant/100 Defiberization Energy
No. parts polymer (kJoule/kg)
I kg/ton 3 kg/ton
1 26 132 124
2 45 125 115
3 67.5 103 67
4 86 98 64
5 216 93 62
A lower defiberization energy will impart a higher degree of softness to the
5 product. In table 6 it can clearly be seen that the defiberization energy
decreases when
the weight ratio of non-ionic surfactants to polymer increases.
Example 7
Two oil emulsions, El and E2, were prepared by mixing coconut oil with two
10 non-ionic surfactants, (1) castor oil ethoxylated with 15 EO and (2) an
unsaturated fatty
alcohol C16-C18 ethoxylated with 5 EO. In emulsion El the weight ratio between
the
coconut oil; non-ionic surfactant (1) and non-ionic surfactant (2) was
5:2.5:2.5, in
emulsion E2 the corresponding ratio was 7:1.5:1.5. The' oil emulsion was
formed by
emulsify 15 g of the oil-surfactant blend, by means of an ultra-turrax, into
85 g of a 0.353
15 wt% dispersion of a silica sol having a specific surface area of 525 m2/g.
An aqueous
polymer solution containing polyDADMAC was also prepared with a concentration
of 0.08
wt%.
The dry paper sheets were prepared by mixing 15 grams of chemical pine
sulphate pulp with water up to 750 ml. The oil emulsion was added to the pulp
suspension whereupon it was agitated for 8 minutes. Then the polymer solution
was
added whereupon the suspension was agitated for 2 minutes. Thereafter, a sheet
was
prepared in a standard PFI-sheetformer (A4 sheets). The sheets were then
pressed,
dried and conditioned according to the standardised method SCAN C26:76. In
trial 3, a
conventional debonder Berocell 589, referred to as Ref. I in Example 1, has
been used
for comparison. When making the sheet, the conventional debonder was added
then the
suspension was agitated for 10 minutes. The defiberization energy was measured
in
accordance with example 2. The results are given in table 7.
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Table 7
Trial Defiberization Energy
(kJoule/kg)
1 El 64
2 E2 62
3 Ref. 1 78
A lower defiberization energy will impart a higher degree of softness to the
product. In table 7, it can clearly be seen that the compositions according to
the invention,
El and E2, gives a lower defiberization energy than the conventional debonder,
Ref.1.
Example 8
The same oil-surfactant blend and polymer solution as no. 5 in table 5 was
prepared in accordance with example 6. In trial 1 the oil-surfactant blend was
emulsified
into the polymer solution to form one single composition.
Paper sheets were prepared by mixing 15 grams of chemical pine sulphate pulp
with water up to 750 ml. The pulp suspension was then agitated for 10 minutes.
In trial 2,
the polymer was added after 8 minutes of agitation. In trials 1 and 3, no
additions were
made to the pulp suspension. After that, a sheet was prepared in a standard
PFI-
sheetformer (A4 sheets). The sheets were then pressed at 4.85 Bar for 5
minutes
resulting in a dry content of about 50 wt%.
In trial 1, the composition was sprayed onto the sheets, in the amount of I
and 3
kg/ton dry cellulosic fibres. In trial 2, the oil emulsion containing the oil-
surfactant blend
was sprayed onto the sheet so that the total addition, together with the
polymer in the
pulp suspension, was 1 and 3 kg/ton dry cellulosic fibres.
In trial 3, a conventional debonder Berocell 589, referred to as Ref: I in
Example
1, has been used for comparison. The conventional debonder has also been
sprayed
onto the sheet in the amount of 1 and 3 kg/ton dry cellulosic fibres.
The sheets were then pressed at 4.85 Bar for 2 minutes, followed by drying on
a
drum at 80 C, for 2 h. After drying the sheets were conditioned in 23 C and 50
% relative
humidity for at least 24 h before testing.
The defiberization energy was then measured in accordance with example 2, the
knot content was measured according to the standardized method SCAN-CM 37 and
the
wetting rate was measured according to the standardized method SCAN-C33:80.
The
results are given in table 8.
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Table 8
Trial Defiberization Energy Knots Wetting Rate
No. (kJoule/kg) (%) (s)
I kg/ton 3 kg/ton 1 kg/ton 3 kg/ton I kg/ton 3 kg/ton
1 97 78 3.66 - 2.00 4.2 4.4
2 93 83 3.66 1.67 4.4 4.7
3 122 84 4.00 2.67 5.0 5.2
The compositions used in trial I and trial 2 show a clear improvement in
defiberization energy, knot content and wetting rate compared to trial 3 in
which a
conventional debonder was used.
Example 9
An oil-surfactant blend was prepared by first mixing coconut oil with an
anionic
surfactant, alkyl benzylsulfonic acid (-C12), and two non-ionic surfactants,
(1) castor oil
ethoxylated with 15 EO and (2) an unsaturated fatty alcohol C16-C18
ethoxylated with 5
EO. The oil-surfactant blend was then emulsified into water to form an oil
emulsion. To
100ml of water 0.3 g of the oil-surfactant blend was used. An aqueous solution
containing
a cationic starch, Amylofax PW, was prepared with a concentration of 0.08 wt%.
The dry paper sheets were prepared by mixing 15 grams of chemical pine
sulphate pulp with water up to 500 ml. The oil emulsion was added to the pulp
suspension at time 0, followed by 10 minutes of agitation. The cationic starch
was added
after 8 minutes. After that, a sheet was prepared in a standard PFI-
sheetformer (A4
sheets). The sheets were then pressed, dried and conditioned according to the
standardised method SCAN C26:76. The cationic starch was added in an amount of
2.5
kg/ton dry cellulosic fibres. The addition of oil emulsion was varied between
0 and 3
kg/ton dry cellulosic fibres. The defiberization energy was measured in
accordance with
example 2. The results are given in table 9.
Table 9
Defiberization energy (kJoule/kg)
Amount of added oil emulsion 0 kg/ton I kg/ton 2 kg/ton 3 kg/ton
168 145 118 90
A lower defiberization energy will impart a higher degree of softness to the
product. In table 9 it can clearly be seen that the defiberization energy
decreases with an
increased amount of oil emulsion.
