U.S. patent application number 13/750503 was filed with the patent office on 2013-05-30 for cellulosic product.
This patent application is currently assigned to AKZO NOBEL N.V.. The applicant listed for this patent is Akzo Nobel N.V.. Invention is credited to Anette Monica HEIJNESSON-HULTEN, John SANDSTROM, Fredrik SOLHAGE.
Application Number | 20130133848 13/750503 |
Document ID | / |
Family ID | 39765041 |
Filed Date | 2013-05-30 |
United States Patent
Application |
20130133848 |
Kind Code |
A1 |
HEIJNESSON-HULTEN; Anette Monica ;
et al. |
May 30, 2013 |
CELLULOSIC PRODUCT
Abstract
The present invention relates to a process of producing a
cellulosic product comprising (i) providing an aqueous suspension
of cellulosic fibers, (ii) adding microfibrillar polysaccharide,
(iii) adding thermoplastic microspheres, (iv) dewatering the
suspension and forming a cellulosic product. The invention also
relates to a process of producing a single layer cellulosic product
comprising (i) providing an aqueous suspension of cellulosic
fibers, (ii) adding microfibrillar polysaccharide derived from
softwood and/or hardwood and optionally adding thermoplastic
microspheres to the suspension, (iii) dewatering the suspension and
forming a cellulosic product. The invention further relates to a
cellulosic product obtainable from said processes. The invention
also relates to a composition comprising microfibrillar
polysaccharide and thermoplastic microspheres and the use
thereof.
Inventors: |
HEIJNESSON-HULTEN; Anette
Monica; (Lerum, SE) ; SOLHAGE; Fredrik;
(Boras, SE) ; SANDSTROM; John; (Stora Hoga,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Akzo Nobel N.V.; |
Arnhem |
|
NL |
|
|
Assignee: |
AKZO NOBEL N.V.
Arnhem
NL
|
Family ID: |
39765041 |
Appl. No.: |
13/750503 |
Filed: |
January 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12999519 |
Dec 16, 2010 |
8388808 |
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PCT/EP2009/057322 |
Jun 15, 2009 |
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13750503 |
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61073149 |
Jun 17, 2008 |
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Current U.S.
Class: |
162/141 ;
524/27 |
Current CPC
Class: |
D21H 17/25 20130101;
D21H 27/10 20130101; D21H 21/54 20130101; D21H 13/00 20130101; D21H
17/24 20130101 |
Class at
Publication: |
162/141 ;
524/27 |
International
Class: |
D21H 13/00 20060101
D21H013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 17, 2008 |
EP |
08158391.6 |
Claims
1-26. (canceled)
27. A composition comprising microfibrillar polysaccharide and
thermoplastic microspheres, wherein the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres ranges
from about 1:100 to about 200:1, and wherein the specific surface
area, as determined by adsorption of N.sub.2 at 177 K according to
the BET method using a Micromeritics ASAP 2010 instrument, of the
microfibrillar polysaccharide is from 3 to 10 m.sup.2/g.
28. The composition according to claim 27, wherein the composition
is aqueous.
29. A cellulosic product obtained by the process comprising the
steps of (i) providing an aqueous suspension of cellulosic fibers,
(ii) adding microfibrillar polysaccharide, (iii) adding
thermoplastic microspheres, (iv) dewatering the suspension and
forming a cellulosic product, wherein the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres ranges
from about 1:100 to about 200:1, and wherein the specific surface
area, as determined by adsorption of N.sub.2 at 177 K according to
the BET method using a Micromeritics ASAP 2010 instrument, of the
microfibrillar polysaccharide is from 3 to 10 m.sup.2/g.
30. A cellulosic product comprising microfibrillar polysaccharide
and thermoplastic microspheres, wherein the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres ranges
from about 1:100 to about 200:1, and wherein the specific surface
area, as determined by adsorption of N.sub.2 at 177 K according to
the BET method using a Micromeritics ASAP 2010 instrument, of the
microfibrillar polysaccharide is from 3 to 10 m.sup.2/g.
31. The cellulosic product according to claim 30, wherein the
product is board or paperboard.
32. The cellulosic product according to claim 30 having a grammage
ranging from about 90 to about 500 g/m.sup.2.
33. The cellulosic product according to claim 30, wherein the
microfibrillar polysaccharide is derived from softwood and/or
hardwood.
34. The cellulosic product according to claim 30, wherein the
cellulosic product contains mechanical, recycled and/or kraft
pulp.
35. The cellulosic product according to claim 30, wherein the
product contains microfibrillar polysaccharide in an amount from
about 0.1 to about 50 wt % based on the weight of cellulosic
product.
36. The cellulosic product according to claim 30, wherein the
product contains thermoplastic microspheres in an amount from about
0.01 to about 10 wt % based on the weight of cellulosic
product.
37. A single layer cellulosic product comprising microfibrillar
polysaccharide derived from softwood and/or hardwood, and
thermoplastic microspheres, wherein the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres ranges
from about 1:100 to about 200:1, and wherein the specific surface
area, as determined by adsorption of N.sub.2 at 177 K according to
the BET method using a Micromeritics ASAP 2010 instrument, of the
microfibrillar polysaccharide is from 3 to 10 m.sup.2/g.
38. The cellulosic product according to claim 37, wherein the
product is board or paperboard.
39. The cellulosic product according to claim 37 having a grammage
ranging from about 90 to about 500 g/m.sup.2.
40. The cellulosic product according to claim 37, wherein the
cellulosic product contains mechanical, recycled and/or kraft
pulp.
41. The cellulosic product according to claim 37, wherein the
product contains microfibrillar polysaccharide in an amount from
about 0.1 to about 50 wt % based on the weight of cellulosic
product.
42. The cellulosic product according to claim 37, wherein the
product contains thermoplastic microspheres in an amount from about
0.01 to about 10 wt % based on the weight of cellulosic
product.
43. A method for producing a liquid packaging board, folding box
board, or liner by (i) providing an aqueous suspension of
cellulosic fibers, (ii) adding microfibrillar polysaccharide, (iii)
adding thermoplastic microspheres, (iv) dewatering the suspension
and forming a cellulosic product, wherein the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres ranges
from about 1:100 to about 200:1, and wherein the final specific
surface area, as determined by adsorption of N.sub.2 at 177 K
according to the BET method using a Micromeritics ASAP 2010
instrument, of the microfibrillar polysaccharide is from 3 to 10
m.sup.2/g.
Description
[0001] The present invention relates to a process of producing a
cellulosic product, such as a single layer cellulosic product and a
composition suitable for addition to a cellulosic suspension. The
invention also relates to a cellulosic product obtainable by the
process, and the use of said cellulosic product.
BACKGROUND OF THE INVENTION
[0002] Today, the development within the papermaking industry is
focused on reducing the grammage of cellulosic products such as
board products while increasing or substantially maintaining their
further properties including strength properties.
[0003] WO 00/14333 relates to a method in which latex is used as a
binder in the bulk layer to improve strength properties. However,
WO 00/14333 suffers from high amounts of chemicals needed as well
as problems related to the application of the latex binder. As an
example, if latex is added to the wet end, retention problems of
the latex on the fibers may cause deposit problems as well as
disturbance of the wet end chemistry balance. Application problems
may also occur if latex were added to already formed paper or board
layers using existing equipment. Latex may also result in
repulpability problems.
[0004] U.S. Pat. No. 6,902,649 discloses a seed-based enhanced
fiber additive (EFA) derived from non-wood which may be used in
papermaking. U.S. Pat. No. 6,902,649 states that EFA used as a
fiber replacement material can maintain or increase paper strength
properties in applications whereby the basis weight of the paper is
decreased.
[0005] One object of the instant invention is to provide a new
process of producing a cellulosic product, especially a single
layer cellulosic product, substantially maintaining and/or
increasing its properties including strength properties such as
tensile strength while using a smaller quantity of cellulosic
material so as to reduce the grammage of the formed cellulosic
sheets. Yet a further object of the invention is to provide a
cellulosic product, especially a single layer cellulosic product,
in which at least one property of the cellulosic product including
tensile strength, Z-strength, and/or other strength is improved or
substantially maintained while the bending resistance can be
substantially maintained or increased. A further object of the
instant invention is to provide a composition which may be used as
a premix to provide such cellulosic product.
The Invention
[0006] The present invention relates to a process of producing a
cellulosic product comprising (i) providing an aqueous suspension
of cellulosic fibers, (ii) adding microfibrillar polysaccharide,
(iii) adding thermoplastic microspheres, and (iv) dewatering the
suspension and forming a cellulosic product.
[0007] The present invention also relates to a process of producing
a single layer cellulosic product comprising (i) providing an
aqueous suspension of cellulosic fibers, (ii) adding microfibrillar
polysaccharide derived from softwood and/or hardwood and optionally
adding thermoplastic microspheres to the suspension (iii)
dewatering the suspension and forming a single layer cellulosic
product.
[0008] The term "cellulosic product", as used herein, includes
inter alia pulp bales and cellulosic products in sheet and web form
such as paper, paperboard, and board. The cellulosic product may
comprise one or several layers containing cellulosic fibers.
[0009] The term "cellulosic product" as used herein, includes e.g.
paperboard comprising cellulosic fibers and solid board, e.g. solid
bleached sulfate board (SBS) including boards (composed of one or
several layers of bleached chemical pulp) coated on the top and
optionally on the backside; solid unbleached sulfate board (SUS)
and solid unbleached board (SUB) which may be made from unbleached
chemical pulp (often coated on the top and sometimes on the
backside which can be composed of several layers of unbleached
chemical pulp in the board); carton board, e.g. folding boxboard
(FBB) which may be made with a middle layer of mechanical pulp
between layers of bleached or unbleached chemical pulp (usually
coated on the top side and being a low density board with high
bending stiffness), folding carton board, liquid packaging board
(LPB) including aseptic, non-aseptic packaging and retortable
boards; white lined chipboard (WLC) (which may comprise middle
layers of different types of recycled fibers and a top layer
usually made from chemical pulp); fluting and corrugated fluting,
unbleached kraftboard, grey chipboard and recycled board; liner,
liner board and container board, cup board, fully bleached or
unbleached kraftliner, testliner, unbleached kraftliner, unbleached
testliner and recycled liner such as OCC, White Top Liner
consisting of a back layer made from unbleached chemical pulp or
brown recycled fibers and a top layer made from bleached chemical
pulp, sometimes including filler such as GCC and PCC; Gypsum board,
Core board, Solid fiber board, the inner layers thereof usually
consisting of recycled fibers and the outer layers of paper with
high tensile strength; sack paper, and wrapping paper.
[0010] According to one embodiment, the invention provides a
cellulosic product such as single layer cellulosic product
comprising microfibrillar polysaccharide and optionally
thermoplastic microspheres distributed throughout the cellulosic
product, e.g. substantially uniformly distributed throughout the
cellulosic product. According to one embodiment, the single layer
cellulosic product may be coated or laminated with any number of
non-cellulosic coating or layer, e.g. polymer films, metallized
films, barrier layers as further disclosed herein.
[0011] By the term "microfibrillar polysaccharide" is meant to
include species derived from polysaccharide without limitation
including cellulose, hemicellulose, chitin, chitosan, guar gum,
pectin, alginate, agar, xanthan, starch, amylose, amylopectin,
alternan, gellan, mutan, dextran, pullulan, fructan, locust bean
gum, carrageenan, glycogen, glycosaminoglycans, murein, bacterial
capsular polysaccharides, and derivatives thereof.
[0012] According to one embodiment, the microfibrillar
polysaccharide is microfibrillar cellulose which would be the most
commonly selected microfibrillar polysaccharide and will therefore
be described more in detail herein. Sources of cellulose for the
preparation of microfibrillar cellulose include the following: (a)
wood fibers, e.g. derived from hardwood and softwood, such as from
chemical pulps, mechanical pulps, thermal mechanical pulps,
chemical-thermal mechanical pulps, recycled fibers, (b) seed
fibers, such as from cotton; (c) seed hull fiber, such as from
soybean hulls, pea hulls, corn hulls; (d) bast fibers, such as from
flax, hemp, jute, ramie, kenaf, (e) leaf fibers, such as from
manila hemp, sisal hemp; (f) stalk or straw fibers, such as from
bagasse, corn, wheat; (g) grass fibers, such as from bamboo; (h)
cellulose fibers from algae, such as velonia; (i) bacteria or
fungi; and (j) parenchymal cells, such as from vegetables and
fruits, and in particular sugar beets, and citrus fruits such as
lemons, limes, oranges, grapefruits. Microcrystalline forms of
these cellulose materials may also be used. Cellulose sources
include (1) purified, optionally bleached, wood pulps produced from
sulfite, kraft (sulfate), or prehydrolyzed kraft pulping processes
and (2) purified cotton linters. The source of the cellulose is not
limiting, and any source may be used including synthetic cellulose
or cellulose analogs. According to one embodiment, the
microfibrillar polysaccharide such as microfibrillar cellulose is
derived from hardwood and/or softwood.
[0013] For purposes of the present invention polysaccharide
microfibrils refer to small diameter, high length-to-diameter ratio
substructures which are comparable in dimensions to those of
cellulose microfibrils occurring in nature. While the present
specification refers to microfibrils and microfibrillation, these
terms are here also meant to include (nano) fibrils with nanometer
dimensions (cellulosic or other).
[0014] According to one embodiment, the microfibrillar
polysaccharide, e.g. microfibrillar cellulose, is modified e.g. by
means of grafting, cross-linking, chemical oxidation, for example
by use of hydrogen peroxide, Fenton's reaction, and/or Tempo;
physical modification such as adsorption, e.g. chemical adsorption;
and enzymatic modification. Combined technologies may also be used
to modify microfibrillar cellulose.
[0015] Cellulose can be found in nature in several hierarchical
levels of organization and orientation. Cellulose fibers comprise a
layered secondary wall structure within which macrofibrils are
arranged. Macrofibrils comprise multiple microfibrils which further
comprise cellulose molecules arranged in crystalline and amorphous
regions. Cellulose microfibrils range in diameter from about 5 to
about 100 nanometers for different species of plant, and are most
typically in the range from about 25 to about 35 nanometers in
diameter. The microfibrils are present in bundles which run in
parallel within a matrix of amorphous hemicelluloses (specifically
xyloglucans), pectinic polysaccharides, lignins, and hydroxyproline
rich glycoproteins (includes extensin). Microfibrils are spaced
approximately 3-4 nm apart with the space occupied by the matrix
compounds listed above.
[0016] According to one embodiment, the polysaccharide is refined
or delaminated to such an extent that the final specific surface
area (determined by adsorption of N.sub.2 at 177 K according to the
BET method using a Micromeritics ASAP 2010 instrument) of the
formed microfibrillar polysaccharide is from about 1 to about 100,
such as from about 1.5 to about 15, or from about 3 to about 10
m.sup.2/g. The viscosity of the obtained aqueous suspension of
microfibrillar polysaccharide can be from about 200 to about 4000,
or from about 500 to about 3000, or from about 800 to about 2500
mPas. The stability, which is a measure of the degree of
sedimentation of the suspension, can be from about 60 to 100, such
as from about 80 to about 100%, where 100% indicates no
sedimentation for a period of at least 6 months.
[0017] According to one embodiment, the microfibrillar
polysaccharide has an arithmetic fiber length from about 0.05 to
about 0.5, for example from about 0.1 to about 0.4, or from about
0.15 to about 0.3 mm. According to one embodiment, the
microfibrillar polysaccharide is added to the cellulosic suspension
in an amount of from about 0.1 to about 50, for example from about
0.5 to about 30, such as from about 1 to about 25 or from about 1
to about 15 or from about 1 to about 10 wt % based on the weight of
the cellulosic product.
[0018] Non-delaminated wood fibers, e.g. cellulose fibers, are
distinct from microfibrillar fibers because the fiber length of
non-delaminated wood fibers ranges usually from about 0.7 to about
3 mm. The specific surface area of cellulosic fibers usually ranges
from about 0.5 to about 1.5 m.sup.2/g. Delamination can be carried
out in various devices suitable for delaminating the fibers of the
polysaccharides. The prerequisite for the processing of the fibers
is that the device is controlled in such way that fibrils are
released from the fiberwalls. This may be accomplished by rubbing
the fibers against each other, the walls or other parts of the
device in which the delamination takes place. According to one
embodiment, the delamination is accomplished by means of pumping,
mixing, heat, steam explosion, pressurization-depressurization
cycle, impact grinding, ultrasound, microwave explosion, milling,
and combinations thereof. In any of the mechanical operations
disclosed herein, it is important that sufficient energy is applied
to provide microfibrillar polysaccharide as defined herein.
[0019] According to one embodiment, the thermoplastic microspheres
are expanded and added as pre-expanded microspheres or as
unexpanded thermally expandable microspheres that preferably are
expanded by heating during the cellulosic product production
process, for example during a drying stage where heat is applied,
or in a separate process step, for example in a cylinder heater or
laminator. The microspheres may be expanded when the cellulosic
product still is wet or when it is fully or almost fully dried. The
microspheres are preferably added in the form of an aqueous slurry
thereof, that optionally may contain other additives desirable to
supply to the stock. The amount of thermoplastic microspheres added
can be for example from about 0.01 to about 10, such as from about
0.05 to about 10, for example from about 0.1 to about 10, from
about 0.1 to about 5, or from about 0.4 to about 4 wt % based on
the weight of cellulosic product.
[0020] According to one embodiment, thermally expandable
thermoplastic microspheres as referred to herein comprise a
thermoplastic polymer shell encapsulating a propellant. The
propellant is preferably a liquid having a boiling temperature not
higher than the softening temperature of the thermoplastic polymer
shell. Upon heating, the propellant increases the internal pressure
at the same time as the shell softens resulting in significant
expansion of the microspheres. Both expandable and pre-expanded
thermoplastic microspheres are commercially available under the
trademark Expancel.COPYRGT. (Akzo Nobel) and are marketed in
various forms, e.g. as dry free flowing particles, as an aqueous
slurry or as a partially dewatered wet-cake. They are also well
described in the literature, for example in U.S. Pat. Nos.
3,615,972, 3,945,956, 4,287,308, 5,536,756, 6,235,800, 6,235,394
and 6,509,384, in US Patent Applications Publication 2005/0079352,
in EP 486080 and EP 1288272, in WO 2004/072160, WO 2007/091960 and
WO 2007/091961 and in JP Laid Open No. 1987-286534, 2005-213379 and
2005-272633.
[0021] According to one embodiment, the thermoplastic polymer shell
of the thermoplastic microspheres is preferably made of a homo- or
co-polymer obtained by polymerising unsaturated monomers. Those
monomers can, for example, be nitrile containing monomers such as
acrylonitrile, methacrylonitrile, .alpha.-chloroacrylonitrile,
.alpha.-ethoxyacrylonitrile, fumaronitrile or crotonitrile; acrylic
esters such as methyl acrylate or ethyl acrylate; methacrylic
esters such as methyl methacrylate, isobornyl methacrylate or ethyl
methacrylate; vinyl halides such as vinyl chloride; vinyl esters
such as vinyl acetate, vinyl ethers such as alkyl vinyl ethers like
methyl vinyl ether or ethyl vinyl ether, other vinyl monomers such
as vinyl pyridine; vinylidene halides such as vinylidene chloride;
styrenes such as styrene, halogenated styrenes or .alpha.-methyl
styrene; or dienes such as butadiene, isoprene and chloroprene. Any
mixtures of the above mentioned monomers may also be used.
[0022] According to one embodiment, the propellant of the
thermoplastic microspheres comprises hydrocarbons such as propane,
butane, isobutane, n-pentane, isopentane, neopentane, hexane,
isohexane, neohexane, heptane, isoheptane, octane or isooctane, or
mixtures thereof. Aside from them, other hydrocarbon types can also
be used, such as petroleum ether, or chlorinated or fluorinated
hydrocarbons, such as methyl chloride, methylene chloride,
dichloroethane, dichloroethylene, trichloroethane,
trichloroethylene, trichlorofluoromethane, perfluorinated
hydrocarbons, etc.
[0023] According to one embodiment, the expandable thermoplastic
microspheres suitable for the invention have a volume median
diameter from about 1 to about 500 .mu.m, for example from about 5
to about 100 .mu.m, or from about 10 to about 50 .mu.m. The
temperature at which the expansion starts, referred to as
T.sub.start, is preferably from about 60 to about 150.degree. C.,
most preferably from about 70 to about 100.degree. C. The
temperature at which maximum expansion is reached, referred to as
T.sub.max, is preferably from about 90 to about 180.degree. C.,
most preferably from about 115 to about 150.degree. C.
[0024] According to one embodiment, pre-expanded thermoplastic
microspheres suitable for the invention have a volume median
diameter from about 10 to about 120 .mu.m, most preferably from
about 20 to about 80 .mu.m. The density is preferably from about 5
to about 150 g/dm.sup.3, most preferably from about 10 to about 100
g/dm.sup.3. Even though pre-expanded thermoplastic microspheres are
commercially available as such, it is also possible to provide them
by thermal on-site expansion of unexpanded expandable thermoplastic
microspheres, for example just before they are added to the stock,
which is facilitated if the expandable microspheres have a
T.sub.start below about 100.degree. C. so steam can be used as a
heating medium.
[0025] According to one embodiment, the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres added
to the aqueous suspension ranges from about 1:100 to about 200:1,
for example from about 1:20 to about 40:1 or from about 1:5 to
about 20:1 or from about 1:2 to about 10:1 or from about 1:1 to
about 8:1 or from about 2:1 to about 5:1. According to one
embodiment, the microfibrillar polysaccharide and the thermoplastic
microspheres are added separately in any order. According to one
embodiment, microfibrillar polysaccharide and thermoplastic
microspheres are added as a premix. According to one embodiment,
the premix further comprises at least one polyelectrolyte, such as
a cationic polyelectrolyte.
[0026] According to one embodiment, the cellulosic product is a
laminate. By the term "laminate" is meant a cellulosic product
comprising at least two layers of paper and/or board. However, the
laminate may also contain further layers of other material than
paper and/or board including films of various polymers, e.g.
polyethylene, polypropylene, polyester, polyvinyl and/or
polyvinylidene chloride, polyvinyl alcohol (PVOH), polyethylene
vinyl alcohol co-polymer, ethylene vinyl acetate co-polymers and
cellulose esters in one or more layers and/or a metallic layer,
e.g. an aluminum film, SiO.sub.x-(where 0<x<=2)) deposited
polymer films, silica-blended polyvinyl alcohol (PVOH) as further
disclosed in US2006/135676 or metallized polymer film which may
function as barrier for gases and which may have low or no
permeability to water, steam, carbon dioxide, and oxygen. Examples
of suitable oxygen barriers include ethylene vinyl alcohol (EVOH),
polyvinylidene chloride (PVDC), PAN (polyacrylo nitrile), aluminum,
metallized films, e.g. of polypropylene or polyethylene
terephthalate, SiO.sub.x-deposited films (where 0<x<=2),
inorganic plate-shaped mineral compounded polymers such as clay
compounded polymers.
[0027] According to one embodiment, the laminate is a packaging
laminate comprising at least one cellulosic layer, at least one
liquid barrier layer and at least one gas barrier layer, said paper
or paperboard comprising, preferably at least at the edges thereof,
expanded or unexpanded expandable thermoplastic microspheres.
[0028] According to one embodiment, the cellulosic product is a
liquid packaging laminate comprising three layers paper or
paperboard, of which preferably at least the middle layer comprises
microfibrillar polysaccharide and/or thermoplastic
microspheres.
[0029] According to one embodiment, the packaging laminate
comprises at least one, preferably at least two liquid barrier
layers on each side of the paper or paperboard base layer(s). A
liquid barrier layer may be made of any material that show no or
insignificant permeability to water. Suitable materials include
polymers of polyethylene like high density or linear low density
polyethylene, polypropylene, PVC, polyesters like polyethylene
terephthalate, and physical or mechanical mixtures thereof. Also
co-polymers can be used, such as co-polymers of ethylene and
propylene. The liquid barrier layer(s) can be applied in any known
ways, such as various lamination methods or the like.
[0030] According to one embodiment, the packaging laminate may
further comprise a gas barrier layer, preferably between a base
layer and a liquid non-permeable layer intended to face the inside
of the package. Any material that show no or insignificant
permeability to molecular oxygen can be used. Examples of materials
include metal foils like aluminium foils, silica coating, e.g.
applied in a coating composition comprising colloidal silica and
optionally various additives as described in WO 2006/065196, or
produced by plasma deposition. Other possible materials include
polymers like polyvinyl alcohol or co-polymers of ethylene and
vinyl alcohol. A gas barrier layer can be applied in any known way,
such as various laminating methods or the like.
[0031] According to one embodiment, the invention concerns a
process for the production of a packaging laminate comprising a
step of applying least one liquid barrier layer and at least one
gas barrier layer to a sheet or web of paper or paperboard
comprising, preferably at least at the edges thereof, expanded or
unexpanded expandable thermoplastic microspheres.
[0032] According to one embodiment, the cellulosic product is a
sealed package for food or beverage products made of a packaging
laminate comprising at least one base layer of paper or paperboard
and at least one liquid barrier layer, and preferably at least one
gas barrier layer, said paper or paperboard comprising, preferably
at least at the edges thereof, expanded or unexpanded expandable
thermoplastic microspheres.
[0033] According to one embodiment, in a single layer cellulosic
product, the grammage is from about 40 to about 1500 g/m.sup.2,
such as from about 60 to about 700 or from about 80 to about 600,
such as from about 90 to about 500 or from about 100 to about 500
g/m.sup.2. The density is preferably from about 100 to about 1200
such as from about 150 to about 1000 or from about 200 to about 800
kg/m.sup.3.
[0034] According to one embodiment, in a cellulosic product of two
layer board the grammage, per layer, is from about 25 to about 750
g/m.sup.2, such as from about 50 to about 400 or from about 100 to
about 300 g/m.sup.2. The density of two layers is preferably from
about 300 to about 1200 kg/m.sup.3, most preferably from about 400
to about 1000 kg/m.sup.3 or from about 450 to about 900 kg/m.sup.3.
The total gram mage is preferably from about 50 to about 1500
g/m.sup.2, most preferably from about 100 to about 800 or from
about 200 to about 600 g/m.sup.2. The total density is preferably
from about 300 to about 1200 kg/m.sup.3, most preferably from about
400 to about 1000 kg/m.sup.3 or from about 450 to about 900
kg/m.sup.3.
[0035] According to one embodiment, in a cellulosic product of
three or more layers the outer layers have a grammage from about 10
to about 750, such as from about 20 to about 400 or from about 30
to about 200 g/m.sup.2. The density of the outer layers is
preferably from about 300 to about 1200 kg/m.sup.3, most preferably
from about 400 to about 1000 kg/m.sup.3 or from about 450 to about
900 kg/m.sup.3. The centre, or non-outer, layer or layers
preferably have a grammage from about 10 to about 750 g/m.sup.2,
most preferably from about 25 to about 400 g/m.sup.2 or from about
50 to about 200 g/m.sup.2. The density of the centre, or non-outer
layer or layers are preferably from about 10 to about 800
kg/m.sup.3, most preferably from about 50 to about 700 kg/m.sup.3
or from about 100 to about 600 kg/m.sup.3. The total grammage is
preferably from about 30 to about 2250 g/m.sup.2, most preferably
from about 65 to about 800 g/m.sup.2 or from about 110 to about 600
g/m.sup.2. The total density is preferably from about 100 to about
1000 kg/m.sup.3, most preferably from about 200 to about 900
kg/m.sup.3 or from about 400 to about 800 kg/m.sup.3.
[0036] According to one embodiment, the cellulosic product has
separate layers for providing liquid and gas barriers,
respectively, but in an embodiment a liquid barrier layer and a gas
barrier layer is provided by a single layer of a material having
both liquid and gas barrier properties.
[0037] According to one embodiment, a multilayered cellulosic
product can be produced by forming the individual layers separately
in one or several web-forming units and then couching them together
in the wet state. Examples of suitable grades of multilayered
cellulosic product of the invention include those comprising from
three to seven layers comprising cellulosic fibers and at least one
of said cellulosic layers comprising thermoplastic microspheres and
microfibrillar polysaccharide. In multilayered cellulosic products
with three or more layers, such as at least one of the middle
layers comprises thermoplastic microspheres and microfibrillar
polysaccharide.
[0038] According to one embodiment, at least one layer of the
cellulosic product can be formed and pressed in a separate stage
before being laminated to a further layer. Following the pressing
stage, the laminate can be dried in conventional drying equipment
such as cylinder dryer with or without dryer wire/felt, air dryer,
metal belt etc. Following drying or during the drying process, the
laminate can be coated with a further layer.
[0039] According to one embodiment, the aqueous suspension contains
cellulosic fibers from chemical pulp, such as sulfate (kraft) and
sulfite pulp, organosolv pulp; recycled fibers; and/or mechanical
pulp including e.g. refiner mechanical pulp (RMP), pressurized
refiner mechanical pulp (PRMP), pretreatment refiner chemical
alkaline peroxide mechanical pulp (P-RC APMP), thermomechanical
pulp (TMP), thermomechanical chemical pulp (TMCP), high-temperature
TMP (HT-TMP) RTS-TMP, alkaline peroxide pulp (APP), alkaline
peroxide mechanical pulp (APMP), alkaline peroxide thermomechanical
pulp (APTMP), thermopulp, groundwood pulp (GW), stone groundwood
pulp (SGW), pressure groundwood pulp (PGW), super pressure
groundwood pulp (PGW-S), thermo groundwood pulp (TGW), thermo stone
groundwood pulp (TSGW), chemimechanical pulp (CMP),
chemirefinermechanical pulp (CRMP), chemithermomechanical pulp
(CTMP), high-temperature CTMP(HT-CTMP), sulfite-modified
thermomechanical pulp (SMTMP), reject CTMP (CTMP.sub.R), groundwood
CTMP (G-CTMP), semichemical pulp (SC), neutral sulfite semi
chemical pulp (NSSC), high-yield sulfite pulp (HYS), biomechanical
pulp (BRMP), pulps produced according to the OPCO process,
explosion pulping process, Bi-V is process, dilution water
sulfonation process (DWS), sulfonated long fibers process (SLF),
chemically treated long fibers process (CTLF), long fiber CMP
process (LFCMP), and modifications and combinations thereof. The
pulp may be a bleached or non-bleached pulp. According to one
embodiment, the aqueous suspension contains mechanical, recycled
and/or kraft pulp.
[0040] Cellulosic fibers can be derived from hardwood, softwood
species, and/or nonwood. Examples of hardwood and softwood include
birch, beech, aspen such as European aspen, alder, Eucalyptus,
maple, acacia, mixed tropical hardwood, pine such as loblolly pine,
fir, hemlock, larch, spruce such as Black spruce or Norway spruce,
and mixtures thereof. Non-wood plant raw material can be provided
from e.g. straws of grain crops, wheat straw reed canary grass,
reeds, flax, hemp, kenaf, jute, ramie, seed, sisal, abaca, coir,
bamboo, bagasse or combinations thereof.
[0041] According to one embodiment, the cellulosic fibers of the
aqueous suspension are derived from hardwood and/or softwood
species.
[0042] According to one embodiment, at least one outer layer of the
cellulosic product is produced from a chemical pulp obtained in
accordance with any of the methods as disclosed herein or other
conventional methods for obtaining chemical pulp. The pulps may be
bleached or unbleached.
[0043] According to one embodiment, a laminate, for example a board
such as a liquid packaging board, comprising at least three layers
is formed whereby the product is obtained by joining directly or
indirectly an inner layer formed from an aqueous suspension
comprising microfibrillar polysaccharide and optionally
thermoplastic microspheres and further layers joined to said inner
layer's respective sides, said further layers being produced from
an aqueous suspension with or without microfibrillar polysaccharide
and optionally thermoplastic microspheres.
[0044] Further layers, e.g. barrier layers, may be formed and
joined on the outer layers as defined. Any of the layers can also
be coated to improve e.g. printability of the laminate. According
to one embodiment, any coated or non-coated layer may in turn be
coated with a plastic or polymer layer. Such coating may further
reduce liquid penetration and improve heat-sealing properties of
the product.
[0045] According to one embodiment, at least one layer of a
laminate is produced from a mechanical and/or chemical pulp
obtained from wood or nonwood pulp in accordance with any of the
methods as disclosed herein or other conventional methods for
obtaining pulp. According to one embodiment, the layer is produced
from at least about 40, e.g. at least about 50, for example at
least about 60 or at least about 75 wt % mechanical pulp based on
the total pulp weight. The pulps may be bleached or unbleached.
[0046] According to one embodiment, the aqueous suspension has a
consistency of cellulosic fibers in an amount from about 0.01 to
about 50, for example from about 0.1 to about 25 or from about 0.1
to about 10 wt %.
[0047] According to one embodiment, the aqueous suspension contains
mineral fillers of conventional types, such as, for example,
kaolin, clay, titanium dioxide, gypsum, talc and both natural and
synthetic calcium carbonates, such as, for example, chalk, ground
marble, ground calcium carbonate, and precipitated calcium
carbonate. The aqueous suspension can also contain papermaking
additives of conventional types, such as drainage and retention
chemicals, dry strength agents, sizing agents, such as those based
on rosin, ketene dimers, ketene multimers, alkenyl succinic
anhydrides, etc.
[0048] The cellulosic product may further comprise a wet strength
agent that is added to the stock before dewatering. Suitable wet
strength agents include resins of polyamine epihalohydrin,
polyamide epihalohydrin, polyaminoamide epihalohydrin,
urea/formaldehyde, urea/melamine/formaldehyde, phenol/formaldehyde,
polyacrylic amide/glyoxal condensate, polyvinyl amine,
poly-urethane, polyisocyanate, and mixtures thereof, of which
polyaminoamide epichlorohydrin (PAAE) is particularly
preferred.
[0049] According to one embodiment, wet and dry strength agents may
be added in amounts from about 0.1 to about 30 kg/t cellulosic
product, such as from about 0.5 to about 10 kg/t pulp. According to
one embodiment, sizing agent(s) may be added in amounts from about
0.1 to about 10, such as from about 0.5 to about 4 kg/t cellulosic
product. Further paper chemicals may be added to the aqueous
suspension in conventional manner and amounts.
[0050] According to one embodiment, the invention is applied on
paper machines producing wood-containing paper or board and/or
paper or board based on recycled fibers, different types of book
and newsprint papers, and/or on machines producing
nonwood-containing printing and writing papers.
[0051] According to one embodiment, the invention further concerns
a composition comprising microfibrillar polysaccharide and
thermoplastic microspheres as disclosed herein. According to one
embodiment, the composition is aqueous. According to one
embodiment, the weight ratio of microfibrillar polysaccharide to
thermoplastic microspheres in the composition ranges from about
1:100 to about 200:1, for example from about 1:20 to about 40:1 or
from about 1:5 to about 20:1 or from about 1:2 to about 10:1 or
from about 1:1 to about 8:1 or from about 2:1 to about 5:1.
[0052] According to one embodiment, the invention further concerns
the use of the composition in the production of a cellulosic
product.
[0053] The invention also regards a cellulosic product obtainable
by the process as defined herein. The invention also regards a
cellulosic product comprising microfibrillar polysaccharide and
thermoplastic microspheres. The invention also regards a single
layer cellulosic product comprising microfibrillar polysaccharide.
The invention also regards a single layer cellulosic product
comprising microfibrillar polysaccharide and optionally
thermoplastic microspheres.
[0054] According to one embodiment, the weight ratio of
microfibrillar polysaccharide to thermoplastic microspheres in the
cellulosic product ranges from about 1:100 to about 200:1, for
example from about 1:20 to about 40:1 or from about 1:5 to about
20:1 or from about 1:2 to about 10:1 or from about 1:1 to about 8:1
or from about 2:1 to about 5:1. According to one embodiment, the
composition comprises an electrolyte such as a cationic
electrolyte.
[0055] According to one embodiment, the cellulosic product may be
any of those obtained herein including any of their properties. For
example, the grammage can be within the ranges as defined herein.
According to one embodiment, the cellulosic product may comprise
any pulp as disclosed herein, especially mechanical pulp, recycled
pulp and/or kraft pulp.
[0056] The invention also concerns the use of the cellulosic
product, e.g. as liquid packaging board, folding box board, or
liner. According to one embodiment, the product is used in the form
of a packaging laminate, which may be used for the production of
sealed packages for liquid, food or non-food products. According to
one embodiment, the invention concerns the use of a cellulosic
product for the production of a sealed package comprising the steps
of forming a container from a packaging laminate, filling the
container with a food or beverage product, and sealing the
container, wherein said packaging laminate comprises at least one
base layer of paper or paperboard and at least one liquid barrier
layer, and preferably at least one gas barrier layer, said paper or
paperboard comprising, preferably at least at the edges thereof,
expanded or unexpanded expandable thermoplastic microspheres.
[0057] In one embodiment the cellulosic product is used for
packaging of food that do not need to be heat treated after the
package has been filled and sealed. Usually such packages are used
for beverages like milk, juice and other soft drinks, soups, and
tomato products.
[0058] In another embodiment the cellulosic product package is used
for food or beverages where the filled and sealed package is heat
treated to increase the shelf life of the content. Such packages
can be used for all kinds of food products, particularly those
traditionally being packed in tin cans, and will herein be referred
to as retortable packages and the material therefore as retortable
packaging laminate or retortable board. Desired properties of a
retortable packaging laminate include ability to withstand
treatment with saturated steam at a high temperature and pressure,
for example from about 110 to about 150.degree. C. at a time from
about 30 minutes to about 3 hours.
[0059] The invention being thus described, it will be obvious that
the same may be varied in many ways. The following examples will
further illustrate how the described invention may be performed
without limiting the scope of it.
[0060] All parts and percentages refer to part and percent by
weight, if not otherwise stated.
EXAMPLE 1
[0061] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 was produced from Timsfors test liner
(Shopper Riegler 47) using a dynamic sheet former (Formette
Dynamic, supplied by Fibertech AB, Sweden). Paper sheets were
formed in the Dynamic Sheet Former by pumping the stock (pulp
consistency: 0.5%, conductivity 2000 .mu.m/s, pH 7) from the mixing
chest through a transversing nozzle into the rotating drum onto the
water film on top of the wire, draining the stock to form a sheet,
pressing and drying the sheet. The amounts of chemicals added to
the suspension (based on the weight of cellulosic product) and
addition time (in seconds) prior to pumping and sheet formation
were the following:
TABLE-US-00001 TABLE 1 Time (s) Amount (%) Product Chemical 120 0
PC155 or Anionic potato starch or BMC MFC (microfibrillar
cellulose) 60 0.2 Eka DR 28HF AKD (alkyl ketene dimer) 45 0.6
Perlbond 970 Cationic potato starch 30 0.03 Eka PL1510 Cationic
polyacrylamide 15 0.05 NP442 Colloidal silica sol 0 Pumping
The dewatering time was 90 s. The paper sheets were pressed at 3
bars in a roll press and thereafter dried restrained in a plane
drier at 105.degree. C. for 16 minutes.
[0062] B) Single layer cellulosic products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but with
addition of 2 and 5% (based on the weight of cellulosic product)
PC155 (anionic potato starch) respectively (B1-B2).
[0063] C) Single layer paper products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but with
addition of 2, 5 and 10% (based on the weight of cellulosic
product) microfibrillar cellulose (prepared from unbleached kraft
pulp from Sodra Cell AB, Sweden) (C.sub.1-C.sub.3). The
characteristics of the microfibrillar cellulose were as follows:
Fiber length: 0.29 mm (Kajaani FS-100 Fiber Size Analyser),
specific surface area 5 g/m.sup.2 (BET method using a Micrometrics
ASAP 2010 instrument), viscosity: 808 mpas, stability:100%
(sedimentation degree of a 0.5% pulp suspension: Water Retention
Value (WRV): 4.0 (g/g) (SCAN-C 62:00).
[0064] Single layer cellulosic products prepared according to A),
B) and C) were analyzed for their grammage, density, tensile
strength, burst strength, Z-strength, geometrical bending
resistance and porosity (see Table 2).
TABLE-US-00002 TABLE 2 A B C Paper Property Unit 1 1 2 1 2 3
Density kg/m.sup.3 572 569 580 576 590 613 Tensile Index Nm/g 50.8
51.8 54.8 55.3 60.4 65.6 Tensile Stiffness kNm/g 6.0 6.0 6.1 6.3
6.6 7.0 Index Bending Nm.sup.6/kg.sup.3 12.3 12.2 12.4 12.8 13.0
13.1 Resistance Index Geom. Bending mN 58 58 61 59 60 61 Resistance
Z-Strength kPa 565 547 564 591 599 649 Burst Index kPa m.sup.2/g
3.3 3.2 3.5 3.6 3.8 4.3 Bendtsen Porosity ml/min 308 325 305 272
182 80
EXAMPLE 2
[0065] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 was produced from a CTMP-pulp (CSF 400)
from Sodra Cell AB using a dynamic sheet former (Formette Dynamic,
supplied by Fibertech AB, Sweden). Paper sheets were formed as in
Example 1, but with a pulp conductivity of 1500 .mu.m/s. The
amounts of chemicals added to the suspension (based on the weight
of cellulosic product) and addition time (in seconds) prior to
pumping and sheet formation were as in Example 1. The sheets were
drained, pressed and dried as in Example 1.
[0066] B) Single layer cellulosic products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but with
addition of 2 and 5% (based on the weight of cellulosic product)
PC155 (anionic potato starch), respectively (B1-B2).
[0067] C) Single layer cellulosic products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but with
addition of 2, 5 and 10% (based on the weight of cellulosic
product) microfibrillar cellulose (prepared from fully bleached
birch kraft pulp fibers from Iggesund) (C.sub.1-C.sub.3). The
characteristics of the microfibrillar cellulose were the following:
Fiber length: 0.37 mm (L&W Fiber Tester), stability: 94%
(sedimentation degree of a 0.5% pulp suspension: Water Retention
Value (WRV): 6.8 (g/g) (SCAN-C 62:00).
[0068] Single layer cellulosic products prepared according to A),
B) and C) were analyzed for their grammage, density, tensile
strength, burst strength, Z-strength, geometrical bending
resistance and porosity (see Table 3).
TABLE-US-00003 TABLE 3 Paper A B C Property Unit 1 1 2 1 2 3
Density kg/m.sup.3 331 320 335 342 363 401 Tensile Nm/g 30.7 31.0
32.7 35.5 41.2 49.4 Index Tensile kNm/g 3.7 3.6 3.8 4.0 4.5 4.8
Stiffness Index Bending Nm.sup.6/ 26.1 27.5 23.0 27.2 24.9 24.4
Resistance kg.sup.3 Index Geom. mN 165 171 134 170 151 146 Bending
Resistance Z-Strength kPa 214 220 246 275 296 416 Burst Index kPa
1.9 1.6 2.0 1.8 2.4 2.6 m.sup.2/g Bendtsen ml/min 1775 1500 1150
912 675 228 Porosity
EXAMPLE 3
[0069] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 were produced from Timsfors test liner
using a dynamic sheet former (Formette Dynamic, supplied by
Fibertech AB, Sweden) as in Example 1, but without chemicals. Paper
sheets were formed, drained, pressed and dried as in Example 1.
[0070] B) Single layer cellulosic products with a grammage of 170
g/m.sup.2 were prepared as in A), but with addition of 2, 5 and 10%
(based on the weight of cellulosic product) microfibrillar
cellulose (prepared from unbleached kraft pulp from Sodra Cell AB,
Sweden) (B1-B3). The characteristics of the microfibrillar
cellulose were the following: Fiber length: 0.29 mm (Kajaani FS-100
Fiber Size Analyser), specific surface area 5 g/m.sup.2 (BET method
using a Micrometrics ASAP 2010 instrument), viscosity: 808 mPas,
stability:100% (sedimentation degree of a 0.5% pulp suspension:
Water Retention Value (WRV): 4.0 (g/g) (SCAN-C 62:00).
[0071] Paper products prepared according to A) and B) were analyzed
for their grammage, density, tensile strength, burst strength,
Z-strength, geometrical bending resistance and porosity (see Table
4).
TABLE-US-00004 TABLE 4 A B Paper Property Unit 1 1 2 3 Density
kg/m.sup.3 569 574 590 609 Tensile Index Nm/g 46.3 56.2 56.2 60.7
Tensile Stiffness Index kNm/g 5.8 6.3 6.4 6.9 Bending Resistance
Index Nm.sup.6/kg.sup.3 12.0 11.8 12.1 13.0 Geom. Bending
Resistance mN 48 56 54 47 Z-Strength kPa 443 581 566 612 Burst
Index kPa m.sup.2/g 2.9 3.4 3.6 4.1 Bendtsen Porosity ml/min 232
275 122 62
EXAMPLE 4
[0072] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 was produced from a CTMP-pulp (CSF 400)
from Sodra Cell AB using a dynamic sheet former (Formette Dynamic,
supplied by Fibertech AB, Sweden) as in Example 1, but without
chemicals. Paper sheets were formed, drained, pressed and dried as
in Example 1. [0073] B) Single layer cellulosic products with a
grammage of approximately 170 g/m.sup.2 were prepared as in A), but
with addition of 2, 5 and 10% (based on the weight of cellulosic
product) microfibrillar cellulose (prepared from fully bleached
birch kraft pulp fibers from Iggesund) (B1-B3). The characteristics
of the microfibrillar cellulose were the following: Fiber length:
0.37 mm (L&W Fiber Tester), stability: 94% (sedimentation
degree of a 0.5% pulp suspension: Water Retention Value (WRV): 6.8
(g/g) (SCAN-C 62:00).
[0074] Single layer cellulosic products prepared according to A)
and B) were analyzed for their grammage, density, tensile strength,
burst strength, Z-strength, geometrical bending resistance and
porosity (see Table 5).
TABLE-US-00005 TABLE 5 A B Paper Property Unit 1 1 2 3 Density
kg/m.sup.3 310 348 378 391 Tensile Index Nm/g 30.3 32.0 36.1 43.1
Tensile Stiffness Index kNm/g 3.3 3.9 4.3 4.6 Bending Resistance
Index Nm.sup.6/kg.sup.3 22.3 21.8 21.8 22.2 Geom. Bending
Resistance mN 99 131 134 118 Z-Strength kPa 93 218 267 336 Burst
Index kPa m.sup.2/g 0.8 1.7 2.1 2.4 Bendtsen Porosity ml/min 505
729 270 205
EXAMPLE 5
[0075] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 was produced from Timsfors test liner
(Shopper Riegler 47) using a dynamic sheet former (Formette
Dynamic, supplied by Fibertech AB, Sweden). Paper sheets were
formed in the Dynamic Sheet Former by pumping the stock (pulp
consistency: 0.5%, conductivity 2000 .mu.m/s, pH 7) from the mixing
chest through a transversing nozzle into the rotating drum onto the
water film on top of the wire, draining the stock to form a sheet,
pressing and drying the sheet. The amounts of chemicals added to
the suspension (based on the weight of cellulosic product) and
addition time (in seconds) prior to pumping and sheet formation
were the following
TABLE-US-00006 [0075] TABLE 6 Time (s) Amount (%) Product Chemical
145 0 BMC MFC (microfibrillar cellulose) 120 0.13 Eka WS XO PAAE
(polyamidoamine epichlorohydrine) 75 0.2 Eka DR 28HF AKD (alkyl
ketene dimer) 60 0.6 Perlbond 970 Cationic potato starch 45 0 820
SL 80 Thermoplastic microsphere or Premix of MFC and 820 SL 80 30
0.03 Eka PL1510 Cationic polyacrylamide 15 0.05 NP442 Colloidal
silica sol 0 Pumping
The dewatering time was 90 s. The paper sheets were pressed at 4.85
bars in a plane press for 7 minutes and thereafter dried in a photo
drier (Japo automatic glazing drier) at 120.degree. C. [0076] B)
Single layer cellulosic products with a grammage of approximately
170 g/m.sup.2 were prepared as in A), but with addition of 1 and 2%
(based on the weight of cellulosic product) 820 SL 80 (B1-B2).
[0077] C) Single layer cellulosic products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but 1% of 820
SL 80 was premixed with 5, 10 and 15% (based on the weight of
cellulosic product) microfibrillar cellulose (prepared from
unbleached kraft pulp from Sodra Cell AB, Sweden)
(C.sub.1-C.sub.3). The characteristics of the microfibrillar
cellulose were the following: Fiber length: 0.29 mm (Kajaani FS-100
Fiber Size Analyser), specific surface area 5 g/m.sup.2 (BET method
using a Micrometrics ASAP 2010 instrument), viscosity: 808 mPas,
stability:100% (sedimentation degree of a 0.5% pulp suspension:
Water Retention Value (WRV): 4.0 (g/g) (SCAN-C 62:00). [0078] D)
Single layer cellulosic products with a grammage of approximately
170 g/m.sup.2 were prepared as in A), but 2% of 820 SL 80 was
premixed with 5, 10 and 15% (based on the weight of cellulosic
product) microfibrillar cellulose (prepared from unbleached kraft
pulp from Sodra Cell AB, Sweden) (D1-D3). The characteristics of
the microfibrillar cellulose were as in C). [0079] E) Single layer
cellulosic products with a grammage of approximately 170 g/m.sup.2
were prepared as in B), but with addition of 10% (based on the
weight of cellulosic product) microfibrillar cellulose (prepared
from unbleached kraft pulp from Sodra Cell AB, Sweden) (E1-E2). The
characteristics of the microfibrillar cellulose were as in C).
[0080] Single layer cellulosic products prepared according to A),
B), C), D) and E) were analyzed for their grammage, density,
tensile strength, burst strength, Z-strength, geometrical bending
resistance, edge wick and porosity (see Table 7a and 7b).
TABLE-US-00007 TABLE 7a A B C Paper Property Unit 1 1 2 1 2 3
Density kg/m.sup.3 669 539 441 581 612 637 Tensile Index Nm/g 48.0
40.3 36.7 46.1 50.5 52.1 Tensile Stiffness kNm/g 4.9 3.9 3.4 4.2
4.7 4.7 Index Bending Nm.sup.6/kg.sup.3 8.3 13.3 17.9 11.6 9.9 8.9
Resistance Index Geom. Bending mN 47 73 95 66 59 53 Resistance
Z-Strength kPa 642 561 395 656 719 721 Burst Index kPa m.sup.2/g
4.0 3.2 2.8 3.8 4.2 4.9 Edge wick kg/m.sup.2 1.7 1.6 1.7 1.4 1.2
1.2 Bendtsen Porosity ml/min 129 392 650 178 88 50
TABLE-US-00008 TABLE 7b D E Paper Property Unit 1 2 3 1 2 Density
kg/m.sup.3 492 502 499 638 511 Tensile Index Nm/g 41.1 46.2 47.5
51.1 47.0 Tensile Stiffness Index kNm/g 3.6 4.0 4.2 4.7 3.9 Bending
Resistance Nm.sup.6/kg.sup.3 14.9 13.4 12.1 9.1 13.6 Index Geom.
Bending mN 87 79 67 59 83 Resistance Z-Strength kPa 526 618 670 712
587 Burst Index kPa m.sup.2/g 3.5 3.9 4.4 4.4 4.0 Edge wick
kg/m.sup.2 1.5 1.5 1.1 1.3 1.5 Bendtsen Porosity ml/min 302 162 70
60 132
EXAMPLE 6
[0081] A) A single layer cellulosic product (A1) with a grammage of
approximately 170 g/m.sup.2 was produced from a hardwood CTMP-pulp
(CSF 465) from M-real using a dynamic sheet former (Formette
Dynamic, supplied by Fibertech AB, Sweden). Paper sheets were
formed in the Dynamic Sheet Former by pumping the stock (pulp
consistency: 0.5%, conductivity 1500 .mu.m/s, pH 7) from the mixing
chest through a transversing nozzle into the rotating drum onto the
water film on top of the wire, draining the stock to form a sheet,
pressing and drying the sheet. The amounts of chemicals added to
the suspension (based on the weight of cellulosic product) and
addition time (in seconds) prior to pumping and sheet formation
were as follows:
TABLE-US-00009 [0081] TABLE 8 Time (s) Amount (%) Product Chemical
145 0 BMC MFC (microfibrillar cellulose) 120 0.13 Eka WS XO PAAE
(polyamidoamine epichlorohydrine) 75 0.2 Eka DR 28HF AKD (alkyl
ketene dimer) 60 0.6 Perlbond 970 Cationic potato starch 45 0 820
SL 80 Thermoplastic microspheres or Premix of MFC and 820 SL 80 30
0.03 Eka PL1510 Cationic polyacrylamide 15 0.05 NP442 Colloidal
silica sol 0 Pumping
The dewatering time was 90 s. The paper sheets were pressed at 4.85
bars in a plane press for 7 minutes and thereafter dried in a photo
drier (Japo automatic glazing drier) at 120.degree. C. [0082] B)
Single layer cellulosic products with a grammage of approximately
170 g/m.sup.2 were prepared as in A), but with addition of 1 and 2%
(based on the weight of cellulosic product) 820 SL 80, (B1-B2).
[0083] C) Single layer cellulosic products with a grammage of
approximately 170 g/m.sup.2 were prepared as in A), but 1% of 820
SL 80 was premixed with 5, 10 and 15% (based on the weight of
cellulosic product) microfibrillar cellulose (prepared from a
ECF-bleached Eucalyptus Globulus kraft pulp from Portugal)
(C.sub.1-C.sub.3). The characteristics of the microfibrillar
cellulose were the following: Fiber length: 0.41 mm ((L&W Fiber
Tester) and stability:94% (sedimentation degree of a 0.5% pulp
suspension; water retention value (WRV): 6.8 g/g. [0084] D) Single
layer cellulosic products with a grammage of approximately 170
g/m.sup.2 were prepared as in A), but 2% of 820 SL 80 was premixed
with 5, 10 and 15% (based on the weight of cellulosic product)
microfibrillar cellulose (prepared from unbleached kraft pulp from
Sodra Cell AB, Sweden) (D1-D3). The characteristics of the
microfibrillar cellulose were as in C). [0085] E) Single layer
cellulosic products with a grammage of approximately 170 g/m.sup.2
were prepared as in B), but with addition of 10% (based on the
weight of cellulosic product) microfibrillar cellulose (prepared
from unbleached kraft pulp from Sodra Cell AB, Sweden) (E1-E2). The
characteristics of the microfibrillar cellulose were as in C):
[0086] Single layer cellulosic products prepared according to A),
B), C), D) and E) were analyzed for their grammage, density,
tensile strength, burst strength, Z-strength, geometrical bending
resistance, edge wick and porosity (see Table 9a and 9b).
TABLE-US-00010 TABLE 9a A B C Paper Property Unit 1 1 2 1 2 3
Density kg/m.sup.3 399 326 283 363 401 403 Tensile Index Nm/g 20.0
17.2 13.8 22.2 28.0 35.0 Tensile Stiffness Index kNm/g 3.0 2.5 1.8
2.9 3.3 3.9 Bending Resistance Index Nm.sup.6/kg.sup.3 16.0 20.7
22.1 19.2 15.6 15.5 Geom. Bending Resistance mN 68 92 96 88 82 73
Z-Strength kPa 262 175 149 293 363 509 Burst Index kPa m.sup.2/g
0.69 0.52 0.48 0.89 1.50 1.96 Edge wick kg/m.sup.2 7.6 7.3 7.3 6.3
5.4 4.3 Bendtsen Porosity ml/min 2138 2412 2750 1700 975 462
TABLE-US-00011 TABLE 9b D E Paper Property Unit 1 2 3 1 2 Density
kg/m.sup.3 320 345 365 393 359 Tensile Index Nm/g 18.9 23.6 31.2
29.1 25.8 Tensile kNm/g 2.4 2.8 3.4 3.4 3.0 Stiffness Index Bending
Nm.sup.6/ 21.5 21.3 18.4 18.8 21.6 Resistance kg.sup.3 Index Geom.
Bending mN 96 96 93 90 103 Resistance Z-Strength kPa 279 299 423
279 313 Burst Index kPa 0.78 1.15 1.47 1.46 1.29 m.sup.2/g Edge
wick kg/m.sup.2 6.4 5.8 4.8 4.9 4.8 Bendtsen ml/min 2225 1575 550
975 1050 Porosity
EXAMPLE 7
[0087] A) Single layer cellulosic products (A1-A5) with a grammage
of approximately 100, 150, 190, 230 and 280 g/m.sup.2 were produced
from a softwood CTMP pulp from Ostrand (CSF 500) using a dynamic
sheet former (Formette Dynamic, supplied by Fibertech AB, Sweden).
Paper sheets were formed in the Dynamic Sheet Former by pumping the
stock (pulp consistency: 0.5%, conductivity 1500 .mu.m/s, pH 7)
from the mixing chest through a transversing nozzle into the
rotating drum onto the water film on top of the wire, draining the
stock to form a sheet, pressing and drying the sheet. The amounts
of chemicals added to the suspension (based on the weight of
cellulosic product) and addition time (in seconds) prior to pumping
and sheet formation were the following:
TABLE-US-00012 [0087] TABLE 10 Time (s) Amount (%) Product Chemical
145 0 BMC MFC (microfibrillar cellulose) 120 0.13 Eka WS XO PAAE
(polyamidoamine epichlorohydrine) 75 0.2 Eka DR 28HF AKD (alkyl
ketene dimer) 60 0.6 Perlbond 970 Cationic potato starch 45 0 820
SL 80 Thermoplastic microspheres 30 0.03 Eka PL1510 Cationic
polyacrylamide 15 0.05 NP442 Colloidal silica sol 0 Pumping
The dewatering time was 90 s. The paper sheets were pressed at 4.85
bars in a plane press for 7 minutes and thereafter dried in a photo
drier (Japo automatic glazing drier) at 120.degree. C. [0088] B)
Single layer cellulosic products with a grammage of approximately
100, 150 and 190 g/m.sup.2 were prepared as in A), but with
addition of 2% (based on the weight of cellulosic product) 820 SL
80, (B1-B3). [0089] C) Single layer cellulosic products with a
grammage of approximately 100, 150 and 190 g/m.sup.2 were prepared
as in B), but with 5% (based on the weight of cellulosic product)
microfibrillar cellulose (prepared from a ECF-bleached Eucalyptus
Globulus kraft pulp from Portugal) (C.sub.1-C.sub.3). The
characteristics of the microfibrillar cellulose were the following:
Fiber length: 0.41 mm (L&W Fiber Tester) and stability:94%
(sedimentation degree of a 0.5% pulp suspension; water retention
value (WRV): 6.8 g/g. [0090] D) Single layer cellulosic products
with a grammage of approximately 100, 150 and 190 g/m.sup.2 were
prepared as in B), but with 10% (based on the weight of cellulosic
product) microfibrillar cellulose (prepared from a ECF-bleached
Eucalyptus Globulus kraft pulp from Portugal) (D1-D3). The
characteristics of the microfibrillar cellulose were as in C).
[0091] E) Single layer cellulosic products with a grammage of
approximately 100, 150 and 190 g/m.sup.2 were prepared as in A),
but with 5% (based on the weight of cellulosic product)
microfibrillar cellulose (prepared from a ECF-bleached Eucalyptus
Globulus kraft pulp from Portugal) (E1-E3). The characteristics of
the microfibrillar cellulose were as in C). [0092] F) Single layer
cellulosic products with a grammage of approximately 100, 150 and
190 g/m.sup.2 were prepared as in A), but with 10% (based on the
weight of cellulosic product) microfibrillar cellulose (prepared
from a ECF-bleached Eucalyptus Globulus kraft pulp from Portugal)
(F1-F3). The characteristics of the microfibrillar cellulose were
as in C). [0093] G) A single layer cellulosic product with a
grammage of approximately 150 g/m.sup.2 was prepared as in A), but
with 3% (based on the weight of cellulosic product) of 820 SL 80
(G1) [0094] H) A single layer cellulosic product with a grammage of
approximately 150 g/m.sup.2 was prepared as in G), but with
addition of 10% (based on the weight of cellulosic product)
microfibrillar cellulose (prepared from a ECF-bleached Eucalyptus
Globulus kraft pulp from Portugal) (H1). The characteristics of the
microfibrillar cellulose were as in C). [0095] I) A single layer
cellulosic product with a grammage of approximately 150 g/m.sup.2
was prepared as in G), but with addition of 15% (based on the
weight of celulosic product) microfibrillar cellulose (prepared
from a ECF-bleached Eucalyptus Globulus kraft pulp from Portugal)
(11). The characteristics of the microfibrillar cellulose were as
in C). [0096] J) A single layer cellulosic product with a grammage
of approximately 150 g/m.sup.2 was prepared as in A), but with
addition of 15% (based on the weight of cellulosic product)
microfibrillar cellulose (prepared from a ECF-bleached Eucalyptus
Globulus kraft pulp from Portugal) (J1). The characteristics of the
microfibrillar cellulose were as in C).
[0097] Single layer cellulosic products prepared according to A),
B), C), D), E), F), G), H), I), and J) were analyzed for their
grammage, density, tensile strength, burst strength, Z-strength,
geometrical bending resistance and porosity (see Table
11a-11d).
TABLE-US-00013 TABLE 11a A B Paper Property Unit 1 2 3 4 5 1 2 3
Grammage g/m.sup.2 102 145 185 231 278 102 146 189 Density
kg/m.sup.3 463 484 467 484 481 339 320 345 Tensile strength kN/m
3.90 5.42 6.51 7.66 9.61 2.9 3.92 5.28 Tensile Stiffness kN/m 445
589 670 740 888 335 406 515 Geom. Bending mN 15 41 84 138 255 27 73
134 Resistance Bending Resistance Nm.sup.6/kg.sup.3 13.3 13.0 12.4
10.6 11.2 24.9 22.4 18.9 Index Z-Strength kPa 376 505 454 469 410
307 278 286 Burst strength kPa 230 361 463 598 662 177 236 318
Bendtsen Porosity ml/min 1462 235 168 95 76 1575 800 400
TABLE-US-00014 TABLE 11b C D Paper Property Unit 1 2 3 1 2 3
Grammage g/m.sup.2 104 146 192 105 149 197 Density kg/m.sup.3 374
358 368 376 379 402 Tensile strength kN/m 3.64 4.70 6.14 3.98 5.61
7.79 Tensile Stiffness kN/m 391 468 572 423 531 680 Geom. Bending
mN 24 70 138 23 62 149 Resistance Bending Resistance
Nm.sup.6/kg.sup.3 20.3 21.4 18.5 19.4 17.9 18.0 Index Z-Strength
kPa 406 368 377 521 494 486 Burst Strength kPa 243 342 424 288 399
570 Bendtsen Porosity ml/min 762 302 260 410 232 145
TABLE-US-00015 TABLE 11c E F Paper Property Unit 1 2 3 1 2 3
Grammage g/m.sup.2 103 147 191 105 151 194 Density kg/m.sup.3 464
468 520 496 537 553 Tensile strength kN/m 4.08 5.92 7.59 4.95 7.04
9.12 Tensile Stiffness kN/m 422 608 738 524 686 838 Geom. Bending
mN 14 47 83 16 39 76 Resistance Bending Resistance
Nm.sup.6/kg.sup.3 11.8 13.9 11.0 13.0 10.2 9.9 Index Z-Strength kPa
458 528 553 514 564 596 Burst Strength kPa 283 439 608 354 507 708
Bendtsen Porosity ml/min 712 175 85 136 140 51
TABLE-US-00016 TABLE 11d G H I J Paper Property Unit 1 1 1 1
Grammage g/m.sup.2 155 148 150 154 Density kg/m.sup.3 337 380 384
542 Tensile strength kN/m 4.05 5.74 6.41 7.63 Tensile Stiffness
kN/m 411 551 582 724 Geom. Bending mN 86 73 70 39 Resistance
Bending Resistance Nm.sup.6/kg.sup.3 25.7 21.7 20.4 10.0 Index
Z-Strength kPa 298 465 532 603 Burst Strength kPa 232 406 469 546
Bendtsen Porosity ml/min 650 200 145 54
* * * * *