SE1550654A1 - Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof - Google Patents
Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof Download PDFInfo
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- SE1550654A1 SE1550654A1 SE1550654A SE1550654A SE1550654A1 SE 1550654 A1 SE1550654 A1 SE 1550654A1 SE 1550654 A SE1550654 A SE 1550654A SE 1550654 A SE1550654 A SE 1550654A SE 1550654 A1 SE1550654 A1 SE 1550654A1
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- Prior art keywords
- pulp
- paper
- pulp slurry
- cured
- paperboard
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/25—Cellulose
- D21H17/26—Ethers thereof
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
- D21H21/22—Agents rendering paper porous, absorbent or bulky
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/002—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/004—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives inorganic compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/005—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives organic compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/66—Salts, e.g. alums
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/30—Multi-ply
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
- D21J1/00—Fibreboard
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
- D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
- D21H11/20—Chemically or biochemically modified fibres
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/65—Acid compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/002—Tissue paper; Absorbent paper
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/002—Tissue paper; Absorbent paper
- D21H27/004—Tissue paper; Absorbent paper characterised by specific parameters
- D21H27/005—Tissue paper; Absorbent paper characterised by specific parameters relating to physical or mechanical properties, e.g. tensile strength, stretch, softness
- D21H27/007—Tissue paper; Absorbent paper characterised by specific parameters relating to physical or mechanical properties, e.g. tensile strength, stretch, softness relating to absorbency, e.g. amount or rate of water absorption, optionally in combination with other parameters relating to physical or mechanical properties
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/08—Filter paper
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/10—Packing paper
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Inorganic Chemistry (AREA)
- Paper (AREA)
Description
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amount of about 20-30% by weight of water. The slurry is then formed to a fibre board,
dewatered and dried at a temperature of 100-125°C for 1 to 3 hours. The metal group is
attached to the phosphate group after curing, whereby the fibre bundle can get an increased
volume and thus the board may get a low density. However, the metal salt is added to the
obtained cellulose phosphate after the cured phosphate-impregnated web is re-slushed and
before the dewatering of the final board material web. Ammonium phosphate is used as a
flame retardant and therefore, there is a need to find materials that are suitable for use in
packaging materials and which are environmentally friendly and safe to use in working
environments.
Thus, even though there are known methods to increase bulk of fibres, there is a need to
provide a process suitable for use in connection with the production of paper and packaging
board.
SUMMARY OF THE INVENTION
lt is an object of the present invention to provide a process for the production of a cured pulp
product that can be used for the production of paper or paperboard with low density and high
bulk.
lt is a further object ofthe present invention to provide a low density paper or paperboard
product suitable for use as packaging material.
lt is also an object of the present invention to minimize problems identified in connection with
the production of prior art low density materials. According to the present invention, cellulosic
fibres are treated to obtain light-weighting of a cellulosic material. The treatment provides
”bulking fibres", which can be used to make bulky paper and paperboard materials while the
bending stiffness can be maintained with a lower basis weight. The bulking fibres can also be
used in the manufacture of tissue paper, filter paper, and fluff pulp, which can be used for
example in absorbent products.
Thus, it is an object with the present invention to provide a process for the production of a
cured pulp product through which bulking fibres can be obtained.
lt is also an object ofthe present invention to provide a treatment of pulp, which results in a
significant reduction of the water retention value, which is beneficial for the dewatering and
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pressing efficiencies during paper/paperboard making, resulting in a higher dry content after
the press-section. Thereby, the need for drying energy in the drying process during
paper/paperboard manufacture can be decreased. Hence, if the treatment step according to
the invention takes place in a pulp mill, and the pulp is used in a non-integrated paper/board
mill, the resource efficiency in the paper or paperboard mill will be much higher both in terms
of material and energy efficiency.
Further objects and advantages will be apparent from the following disclosure of the present
invention.
The objects above are attained by a process according to the first embodiment of the
invention relating to a process for the production of a cured pulp product suitable for use in
the production of paper, paperboard, tissue paper, filter paper, or fluff pulp, comprising the
steps of:
i) providing a first aqueous pulp slurry comprising cellulosic fibres and having a
pulp consistency of from 0.1 to 40 % by weight, calculated as dry weight of the
cellulosic fibres in the first pulp slurry;
ii) adjusting the pH of the first pulp slurry to a pH of from pH 1.5 to pH 4.5, or
alternatively treating the first pulp slurry with a metal salt containing divalent
metal ions selected from Zn", Mgn, Ca” or mixtures thereof, to a total molar
concentration of from 0.0001 M to 0.5 M in the first pulp slurry;
iii) attaching an anionic or an amphoteric carboxymethyl cellulose (CMC) or a
derivative thereof to the cellulosic fibres in the first pulp slurry by treating the
pulp with the CMC at a temperature of at least 50°C;
iv) adding to the first pulp slurry a metal salt comprising Al3+ ion to a total molar
concentration of aluminium ions of from 0.0001 M to 0.5 M in the first pulp
slurry, or alternatively controlling the concentration of the divalent metal ions
in the pulp slurry and adjusting the total molar concentration of the divalent
metal ions to a range of from 0.0001 M to 0.5 M in the first pulp slurry, if the
total molar concentration is not within the range of from 0.0001 M to 0.5 M in
the first pulp slurry;
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v) controlling the pH and adjusting the pH of the first pulp slurry to a pH of from
pH 3.0 to pH 6.0 if the pH is not within the range of from 3.0 to 6.0;
vi) dewatering and curing the first pulp slurry at a temperature of at least 60°C and
thus provide a cured pulp product.
This process is also herein below referred to as a ”dry” process since it includes a step of
curing. ln the process, when the fibres are treated with multivalent metal ions (cations) in
acidic conditions in steps iv) and v), the hornification ofthe fibres increases and thereby stiffer
fibres are obtained.
Hornification refers to an irreversible internal bonding in lignocellulosic fibre materials that
takes place upon water removal or drying/curing. The hornified fibres do not swell to the
same extent as the non-hornified fibres (i.e. they cannot take up as much water) and this
difference can e.g. be measured as a decrease in water retention value. The irreversible
bonding also leads to a stiffening of the polymer structure in the fibres and papers made from
stiffer fibres are bulkier. . Thus, the process according to the first aspect ofthe invention
provides bulking fibres and leads to webs that are easy to dewater during a papermaking
pFOCESS.
By the attachment of CMC to the fibres the charge density, or the anionic charge density of
the fibres can be increased, which is beneficial in the following paper making process.
lt should be noted that in the present application, when an interval from a first value to a
second value is described, it is meant that any individual value within the claimed interval may
be chosen. For example, regarding the pulp consistency in the interval ”of from 0.1 to 40 % by
weight", it is meant that any value within the interval, such as 1%, 10%, or 40% may be chosen
for the pulp consistency. Further as an example and in a corresponding way the pH may be
chosen to be any pH value within the claimed interval of from 3.0 to 6.0 and can be for
example pH 3.5, pH 5.0, or pH 6.0.
According to one embodiment the first pulp slurry is dewatered and subsequently or
concurrently cured by means of flash drying. Flash drying is suitably performed at a
temperature that is higher than for example when drying by means of heated cylinders, and
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the temperature can be from 100 to 300°C, depending on the at sensitivity of the first pulp
slurry. Also the curing time is normally shorter when flash drying is used. By flash drying a
further bulking effect, i.e. a higher bulk with lower density, may be obtained. Thus, in the step
vi) the first pulp slurry can be cured by means of flash drying at a temperature from 100°C to
300°C, preferably from 150°C to 270°C and most preferably from 180°C to 240°C. The curing
time can be less than 5 minutes, preferably less than one minute. Therefore, essentially
shorter curing time may be obtained compared to traditional curing methods.
According to another embodiment, in the step vi) the first pulp slurry is cured at a
temperature from 60 to 150°C by means of heated air or steam, wherein the heated air or
steam is lead directly to heat the first pulp slurry or indirectly to heat the first pulp slurry, for
example heated cylinders. The higher the temperature during the curing is, the higher will the
bulk be, and thus the bulking effect. By using these curing methods in the step vi), it is possible
to provide the cured pulp product in the form of a web, i.e. a cured web. The web may then be
collected and rolled up to web rolls and then provided to a papermaking mill. The process may
then further comprise a step vii) comprising cutting the cured web into sheets and stacking
the sheets to provide bales of pulp. The bales of pulp are easy to transport to a paper mill and
can be readily used in a papermaking process.
ln the process in the step vi) the first pulp slurry is preferably cured until a moisture content of
below 50%, suitably below 30%, and preferably below 15% is obtained. The moisture content
may be 0%, but usually the moisture content is from about 1 to 10%. The more the web is
cured, the greater will the density decrease ofthe material be and thus the greater the bulking
effect obtained.
The metal salt comprising the multivalent, i.e. divalent or trivalent, metal ion is preferably
added to the first pulp slurry in the step iv) at a molar concentration of from 0.0001 M to 0.05
I\/I which is sufficient to obtain bulking effect while the risk for deteriorating the quality of the
fibres is minimized. According to one preferable variant the multivalent metal ion added in the
step iv) is Al3+, which is commonly known in papermaking.
The pulp consistency of the first aqueous pulp slurry is of from 0.5% to 30%, preferably of
from 1% to 20%, calculated as dry weight of the cellulosic fibres in the first pulp slurry.
Preferably, the pulp concentration is as high as possible, whereby a more effective ion
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exchange can be achieved, and thus the concentration ofthe added metal salt can be kept at a
low level.
The CMC can be amphoteric and have a cationic molar substitution degree of from 0.00001
and 0.4 and an anionic molar substitution degree of from 0.3 to 1.2, and wherein a net charge
of the CMC is anionic. By using amphoteric CMC, the amount of the CMC used can be
decreased and still a sufficient amount can be attached to the fibres. However, the CI\/IC may
also be anionic and have an anionic molar substitution degree of from 0.3 to 1.2. Generally,
anionic CMC is cheaper, and even though larger amount of anionic CMC is needed for
attaching an equal amount of CMC to fibres than amphoteric CMC, a more economical process
can be provided if anionic CMC is used. The amount of the anionic or amphoteric CMC
attached during the treatment is suitable of from 1 mg/g to 100 mg/g, based on the weight of
the cellulosic fibres in the first pulp slurry.
The first aqueous pulp slurry may comprise a pulp selected from a kraft, soda, sulfite,
mechanical, thermomechanical, semi-chemical or chemi-thermomechanical pulp, or mixtures
thereof, and will be explained more in detail below.
The present invention also relates to a cured pulp product obtained by the process.
The cured pulp product may then be used in several applications, such as in the production of
paper or paperboard, tissue paper, filter paper, or fluff pulp. According to one aspect, the
invention further relates to a process for the production of paper or paperboard comprising
the steps of:
a. providing a cured pulp product as defined above to a paper making process;
b. re-slushing the cured pulp product to provide a second pulp slurry;
c. dewatering the second pulp slurry to provide a web of paper or paperboard;
d. drying the web of paper or paperboard to provide a dried web of paper or
paperboard.
The processes for the production of paper or paperboard described above may further
comprise adding a dry strength aid or a wet strength resin to the first pulp slurry, suitably for
example between the steps b. and c. ln this way the strength ofthe paper or paperboard can
be improved, while still maintaining an improved bulking effect.
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According to a second embodiment ofthe invention, paper or paperboard may be produced in
an integrated paper mill, i.e. a mill that comprises both a pulp mill and a paper mill without
drying the pulp before the paper/board machine. In an integrated paper mill it has been found
that it is not necessary to cure the pulp before a paper or paperboard making process. Thus,
the present invention also relates to a process for the production of paper or paperboard
suitable for use as a packaging board. The definition paper also includes e.g. tissue paper and
filter paper. The process according to a further embodiment comprises the steps of:
I. providing a first aqueous pulp slurry comprising cellulosic fibres and having a
pulp consistency of from 0.1 to 40 % by weight, calculated as dry weight of the
cellulosic fibres in the first pulp slurry;
II. adjusting the pH ofthe first pulp slurry to a range between pH 1.5 to pH 4.5, or
alternatively treating the first pulp slurry with a metal salt containing divalent
metal ions selected from Zn2+, Mgzfl Ca2+ or mixtures thereof, to a total molar
concentration ofthe metal salt of from 0.0001 to 0.5 M in the first pulp slurry;
|||. attaching an anionic or amphoteric carboxymethyl cellulose (CMC) or a
derivative thereof to the cellulosic fibres in the first pulp slurry by treating the
pulp with the CMC at a temperature of at least 50°C;
IV. adding to the first pulp slurry a metal salt comprising an AI3+ metal ion to a
molar concentration of from 0.0001 I\/I to 0.5 I\/I in the first pulp slurry, whereby
an ion-exchange occurs;
V. providing the first pulp slurry to a papermaking process and thus provide a
second pulp slurry;
VI. dewatering the second pulp slurry to provide a web of paper or paperboard;
VII. drying the web of paper or paperboard to provide a dried web of paper or
paperboard.
This process is also referred to as a ”wet” process, since the curing step before the paper
making process is omitted.
In the process, in the step IV) it has been found that aluminium containing metal salt
comprising is suitable for use. Without binding the applicant to any specific theory, one
possible explanation is that by the presence of aluminium ions it is possible to increase the
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friction between the fibres on the surface. Therefore, it is possible to maintain the network of
the fibres during drying and thus it is possible to provide higher bulk. Thus, according to this
embodiment, the addition of aluminium ion Al3+ is essential, while the curing step before the
papermaking process is not essential. Thus, in this way pulp slurry with a high bulk can be
provided for the use in an integrated mill.
ln the dry and wet processes described above, the first aqueous pulp slurry may comprise a
chemical pulp selected from a sulfate, kraft, soda, or sulfite pulp, a mechanical pulp, a
thermomechanical pulp, a semi-chemical pulp (e.g., a neutral sulphite semi-chemical pulp;
NSSC), or a chemi-thermomechanical pulp, or mixtures thereof. According to one variant, the
first pulp slurry comprises kraft pulp, whereby a high quality raw material for the process can
be provided.
The pulp consistency of the first aqueous pulp slurry is suitably from 0.5% to 30% and
preferably from 1% to 20%. Preferably, the pulp concentration is as high as possible, whereby
a more effective ion exchange can be achieved, and thus the concentration of the added metal
salt can be kept at a low level.
The CMC can be anionic or amphoteric. According to one embodiment, the CMC is amphoteric
and has a cationic molar substitution degree between 0.00001 and 0.4, and an anionic molar
substitution degree from 0.3 to 1.2.
According to another embodiment, the CMC is anionic and has an anionic molar substitution
degree of from 0.3 to 1.2. Anionic CMC is cheaper to produce and thus a more economical
process can be provided if anionic CMC is used.
The amount of CMC used during the treatment can be from 1 to 100 mg/g, based on the
weight of the cellulosic fibres in the first pulp slurry. By using the specific amount, all CI\/IC can
be attached to the cellulosic fibres. Thus, the attached amount of CMC can be from 1 to 100
mg/g-
Further in the wet process described above, in the step iv) a metal salt comprising an AIS*
metal ion can be added to the first pulp slurry to a total molar concentration of aluminium
ions of from 0.0001 [VI to 0.05 I\/I, whereby ion-exchange occurs. The concentration of the
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aluminium salt in the specific range is sufficient to obtain a bulking effect on different bulking
levels.
The processes for the production of paper or paperboard described above may further
comprise adding a dry strength aid or a wet strength resin to the first pulp slurry, suitably for
example between the steps V. and VI. ln this way the strength of the paper or paperboard can
be improved, while still maintaining an improved bulking effect.
Further, the present invention relates to a paper or paperboard obtained by the processes as
described above. The paper or paperboard product may have a structural density of from 150
to 600 kg/ma according to SCAN-P-88:01, whereby a low density product can be provided for
packaging purposes. Preferably, the paper or paperboard product is used as a packaging
material, and more preferably as a middle layer in a paper board, whereby the bulk of the
board can be increased.
lt has also been found that the cured pulp product obtained according to the first
embodiment of the process, the ”dry” process described process in steps i)-vi) can also be
used for the production of a fluff pulp or filter or tissue paper. The fluff pulp may be further
used for example in absorbent products.
Further features and advantages of the present invention are described in the following
detailed description and examples with reference to the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a flow chart which shows the main steps of the present process according to a first
embodiment, ”dry process";
Fig. 2 is a flow chart which shows the main steps of the present process according to a second
embodiment, ”wet process";
Fig. 3 shows a graph which illustrates effects on the water retention value of a pulp obtained
from a process according to the first embodiment of the invention, the ”dry process", with
attachment levels of 20 mg/g and 40 mg/g amphoteric CIVIC and drying the sheets at 120°C for
2 h and re-slushing the pulp and forming sheets.
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Fig. 4 shows a graph which illustrates effects on the sheet density of a pulp obtained from a
process according to the first embodiment of the invention, the ”dry process", with
attachment levels of 20 mg/g and 40 mg/g amphoteric CMC and drying the sheets at 120°C for
2 hrs and re-slushing the pulp and forming sheets.
Fig. 5 shows a graph which illustrates the effect of curing temperature on water retention
value when pulp is treated with 20 mg/g amphoteric CMC and the pulp is in its Alsïform
(0.005 I\/I) and pH 3.5 and dried at 120 °C for 2 hrs (”dry process").
Fig. 6 shows a graph which illustrates the effect of different metal ions on water retention
value when pulp is treated with 20 mg/g anionic CMC and the pulp is in its AIEH-form (0.005 M)
and pH 3.5 and the curing temperature at 120°C for 2 hrs (”dry process").
Fig. 7 shows a graph which illustrates the tensile index versus structural density of paper
sheets pressed to different densities when the pulp was treated with 20 mg/g anionic CMC
and the pulp is in its different ionic forms (Na+, Ca” and Al3+), ”wet process".
DETÅlLED DESCRIPTION
There is a long-time felt need for lighter and stronger packaging materials. The inventors of
the present invention have found an economical and efficient method to treat fibres in a
process that increases the bulk of paper or paperboard materials and thus provides lighter
packaging materials while the mechanical properties ofthe material can be maintained
sufficiently by using chemical additives for packaging purposes.
Below, general descriptions for some of the used definitions in this application are given.
Definitions paper or paperboard are used equally in this context and are meant to relate to a
material made from pulp and which comprises cellulosic fibres. Paper is manufactured from
cellulosic fibres by pressing the moist fibres together and then dewatering and/or drying the
fibres into a thin, flexible material. Paper may be a single layer product or it may contain
several layers. By paper is also meant equally e.g. printing paper, tissue paper, filter paper and
paperboard. Paperboard or packaging board is a cardboard product made from a pulp, and
can be made of several layers of paper.
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By tissue paper is meant a very thin or light weight paper often produced with a paper
machine comprising a steam heated drying cylinder (yankee cylinder) or by through-air-drying
(TAD) of the tissue paper. Tissue paper has often good absorbent capacity, for example from
about 1 g liquid/1 g fibre, but may be more or less depending on the quality ofthe tissue
pa per.
Fluff pulp is pulp having absorbent properties. Fluff pulp is often based on a chemical pulp,
preferably kraft pulp or a chemi-thermomechanical pulp (CTI\/IP). Preferably, the raw material
used comprises long fibres, and can be derived from soft wood material, such as spruce, pine,
fir, larch, cedar, and hemlock.
Filter paper is a paper used for filter applications where a passing fluid is passed through the
paper to capture for instance particles. The passing fluid may be a gas such as air or a liquid
such as water. Fluff pulp is pulp having absorbent properties.
Cellulosic fibres are fibres originating from unbleached or bleached pulp comprising a pulp
selected from a kraft, soda, sulfite, mechanical, a thermomechanical pulp (TI\/IP), a semi-
chemical pulp (e.g., neutral sulfite semi-chemical pulp; NSSC), recycled pulp or a chemi-
thermomechanical pulp (CTMP). The raw material for the pulps can be based on softwood,
hardwood, recycled fibres or non-wood fibres suitable for making paper or
paperboard/cardboard. The softwood tree species can be for example, but are not limited to:
spruce, pine, fir, larch, cedar, and hemlock. Examples of hardwood species from which pulp
useful as a starting material in the present invention can be derived include, but are not
limited to: birch, oak, poplar, beech, eucalyptus, acacia, maple, alder, aspen, gum trees and
gmelina. Preferably, the raw material mainly comprises softwood. The raw material may
comprise a mixture of different softwoods, e.g. pine and spruce. The raw material may also
comprise a non-wood raw material, such as bamboo and bagasse. The raw material may also
be a mixture of at least two of softwood, hardwood and/or non-woods.
By pulp consistency is meant dry content in an aqueous pulp slurry. That is, for example a
consistency of 10% means that the weight of the dry matter is 10%, based on the total weight
of the pulp slurry.
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By curing is meant that a physical or chemical reaction occurs in the material in addition to
evaporation of water. By drying is meant evaporation or draining away water or other liquids
from a material.
Dewatering is a procedure by which water is removed from a wet pulp web. Dewatering can
be performed mechanically during the web formation on a wire for example by means of
vacuum or centrifugal forces. Dewatering may also be performed by means of mechanical
forces, e.g. by means of pressing, e.g. in a pressing section of a paper machine. After
dewatering on a wire and/or mechanical dewatering, the web can be forwarded to a drying
section, in which the remaining water/moisture in the web is evaporated by means of heat,
which is also called thermal dewatering. The drying section may be designed in different ways
and can comprise e.g. multi-cylinder dryer, yankee cylinder drying, through-air drying or flash
drying equipment.
By moisture content is meant the water content of the material expressed in weight %, and
based on the total weight of the material.
By water retention value is meant a test value that provides an indication of fibres' ability to
take up water and swell, and is in this application measured by means of a standard method
SCAN-C 62:00 unless otherwise stated.
ln this application, the definition of re-slushing is used equally with re-pulping and re-slurrying
and means that a cured pulp is re-suspended in water to provide an aqueous suspension
containing cellulosic fibres.
ln the present application by bulking fibres are meant fibres that after treatment obtain a
more bulky material structure than fibres that have not been treated. By bulking effect is
meant an effect which decreases the density of a material compared to a material that has not
been treated.
By molar concentration is meant the concentration or the amount of a substance (mole) in
one dm3 or litre of a mixture, e.g. molar concentration of metal ions equals to moles of the
ions in one litre of an aqueous solution/suspension containing water and a metal salt.
By ”degree of substitution" or ”DS”, is meant the number of substituted ring sites of beta-
anhydroglucose rings of the carboxymethyl cellulose, CMC. Since there are three hydroxyl
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groups on each anhydroglucose ring of the cellulose that are available for substitution, the
maximum value of DS is 3.0.
The carboxymethylcellulose (CMC) used in the present invention is anionic or amphoteric. lt is
essential that the CMC is charged, however, the reaction agent to render the Cl\/IC charged
needs not be of any specific kind. The amphoteric CMC has an anionic net charge. Any anionic
or amphoteric C|\/IC suitable for use in papermaking industry could be used in the
embodiments of the present process. Anionic or amphoteric CMC and reaction agents to
render the Cl\/IC charged are known to the skilled person in the art and examples, which
should not be considered to be limiting, of the CMC usable in the present invention are
described below.
The anionic carboxymethyl cellulose (CMC) useful in the process ofthe present invention has a
degree of substitution of up to the theoretical limit of 3.0, but preferably from about 0.30 to
1.20 carboxymethyl substituents per anhydroglucose unit of cellulose.
The CMC usable in the present invention has a net anionic charge, but may comprise also
cationic groups whereby the CI\/IC is amphoteric. An amphoteric CMC can have a cationic
degree of substitution in the range of from 0.00001 to 1.0, preferably from 0.00001 to 0.4. The
amphoteric CI\/IC can also have an anionic degree substitution in the range of from 0.3 to
about 1.20.
Examples of suitable anionic groups include carboxylate, e.g. carboxyalkyl, sulphonate, e.g.
sulphoalkyl, phosphate and phosphonate groups in which the alkyl group can be methyl, ethyl
propyl and mixtures thereof. The Cl\/IC suitably contains an anionic group comprising a
carboxylate group, e.g. a carboxyalkyl group. The counter-ion of the anionic group can be an
alkali metal or alkaline earth metal ion, such as sodium.
Examples of suitable cationic groups of CMC can include salts of amines, suitably salts of
secondary ammonium groups, tertiary amines, and quaternary ammonium groups. The
substituents attached to the nitrogen atom of secondary ammonium groups, amines and
quaternary ammonium groups can be the same or different and can be selected from e.g.
alkyl, cycloalkyl, and alkoxyalkyl groups. The substituents can comprise from 1 to about 24
carbon atoms, independently of each other. The nitrogen of the cationic group can be
attached to the CMC directly or by means of a linking chain of atoms which can comprise
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carbon and hydrogen atoms, and optionally oxygen and/or nitrogen atoms. For example the
linking chain of atoms can be an alkylene group with from 2 to 18 carbon atoms, and may
contain one or more O or N atoms. Examples of CMC containing cationic groups include those
obtained by reacting CIVIC with a quaternization agent selected from 2,3-(epoxypropyl)
trimethylammonium chloride, (4-chlorobutene-2)-trimethylammonium chloride, 2-
diethylaminoethyl chloride and mixtures thereof.
The cationic groups are suitably quaternary ammonium groups and then the cationic degree of
substitution referred to herein is the same as the degree of substitution of quaternary
ammonium groups.
The anionic and/or amphoteric CMC usually has an average molecular weight which is at least
20 000 Dalton, preferably at least 50 000 Dalton, and up to about 1 000 000 Dalton, preferably
up to about 500 000 Dalton.
The amount of CMC added to the pulp slurry during the treatment can be from 5 to 100 mg/g
fibres, based on the weight of the cellulosic fibres in the first pulp slurry. Suitably, the amount
is from about 10 to 30 mg/g, based on the weight of the cellulosic fibres in the first pulp slurry.
All CMC can be attached to the fibres, and therefore the attached amount of CMC
corresponds to the added amount, e.g. from 5 to 100 mg/g fibres.
Process description
As already mentioned above, it is desirable to produce packaging materials with a higher bulk.
However, despite prior art solutions there is still a need to improve processes to produce
bulky paper, such as tissue paper or filter paper, paperboard, or fluff pulp in an economical
and efficient way. lt is also desirable that existing process equipment can be used to produce
paper or paperboard. lt is thus essential that the characteristics of the treated pulp material or
product used in paper mills do not negatively affect the papermaking process. lt is desirable
that the paperboard production in the existing paper mills can be run with as few
modifications as possible.
According to the first embodiment of the present process, which is also in this context
referred to as a ”dry process", it is possible to provide a cured pulp product in the form of a
web of pulp, bales of pulp or flakes of pulp for a further production of paper or paperboard in
a paper mill orfactory. The flakes may be in the form of a free flowing material or the flakes
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may be gathered to bales. ln the process the pulp is treated with multivalent metal ions, such
as aluminium, calcium, magnesium or zinc ions (cations) so as to obtain bulking fibres.
When the pulp is cured, the physical/chemical reactions that occur during curing render the
internal structure of the pulp material stabilized before further processing ofthe cured pulp
product. Therefore, the fibres show less swelling when re-slushed during paper or paperboard
manufacture than fibres that are not treated. Thus, for example significant lowering of the
water retention value can be obtained when the cured pulp product ofthe invention is used
compared to a pulp material that is not cured. This is beneficial for the pressing efficiency.
Thereby, a higher dry content after the press section in a paper machine may be obtained,
which is especially beneficial in paper mills having limited drying capacity.
When the pulp is provided in an integrated paper mill, according to the second embodiment
of the present invention the pulp is not cured before it is provided to the paper or paperboard
making process. By the treatment with aluminium salts during the paper or paperboard
making process it is possible to increase the bulk ofthe obtained paper or paperboard.
Without binding the applicant to any specific theory, this may be caused by the increased
friction between fibres on the surface of the pulp product and therefore, it is possible to
maintain the network of the fibres during curing and thus it is possible to provide a structure
with higher bulk.
The processes according to the embodiments of the present invention have been found to be
efficient to produce paper-based products having a higher bulk than paper-based products
produced from non-treated pulps. Also, during the paper making process the pulp can be
mechanically pressed to higher solids content and therefore drying energy is saved during the
paper or paperboard making processes. As mentioned above, a further advantage is that that
the productivity of drying-limited paper/board machines can be enhanced.
A first embodiment ofthe present process is illustrated in Fig. 1 in which steps ofthe process
are illustrated in a flow chart. The first embodiment of the present process is also referred to
as a ”dry process”. A second embodiment of the present process is illustrated in Fig. 2 in which
steps of the process are illustrated in a flow chart. The second embodiment ofthe present
process is also referred to as a ”wet process”. By the first embodiment of the present process
a cured pulp product suitable for use for the production of paper, paperboard, tissue or filter
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paper or fluff pulp can be provided. Fluff pulps are commonly used in for example absorbent
products.
By the second embodiment ofthe present process it is possible to provide a treated pulp
usable directly in a papermaking process, e.g. in an integrated pulp and paper mill, and
provide paper or paperboard with increased bulk. ln the second embodiment of the invention,
no curing is performed between the pulp treatment and the papermaking process.
”D ry” process
Returning to Fig. 1 and the first embodiment ofthe present invention, in the first step i) of the
process an aqueous first pulp slurry is provided. The first pulp slurry comprises cellulosic fibres
and has a pulp consistency of from about 0.1 to 40 wt-%, calculated as a dry content of
cellulosic fibres in the first pulp slurry. The first pulp slurry may thus be a low consistency pulp
having a dry content of from 1 to 4%, medium consistency pulp having a dry content of from 8
to 12 % or high consistency pulp having a dry content of from about 20 to 40%. Suitably the
consistency is from 0.5 to 30 %, and preferably from 1 to 20%, calculated as a dry content of
cellulosic fibres in the first pulp slurry.
The raw material may be selected from any of softwood, hardwood, recycled fibres or non-
wood fibres that are suitable for making paper or paperboard/cardboard or mixtures thereof.
The first pulp slurry may comprise or consist of an unbleached or a bleached pulp which can
comprise or consist of a chemical pulp such as a kraft (sulfate), soda or sulfite pulp. The pulp
may also comprise or consist of a mechanical pulp, thermomechanical pulp (TM P), semi-
chemical pulp (e.g., neutral sulfite semi-chemical pulp; NSSC), recycled pulp or chemi-
thermomechanical pulp (CTMP). The pulp may consist of one type of pulp or the pulp may
comprise two or more pulps as a mixture. Preferably, the cellulosic fibres originate from a
chemical pulping process, which provides high quality pulps. Suitably, the fibres are derived
from a kraft pulping process.
The next step ii) of treating the first pulp slurry can be performed in two alternative ways.
According to a first alternative, the pH of the pulp slurry is adjusted to an acidic range, i.e. to a
pH value of from 1.5 to 4.5. The pH adjustment can be performed by using any suitable acid,
preferably an inorganic acid such as sulphuric acid. According to a second alternative in the
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step ii) the first pulp slurry is treated with a metal salt containing divalent metal ions (cations).
The total metal ion concentration in the first pulp slurry is adjusted to a total concentration of
from 0.0001 to 0.05 M in the first pulp slurry, preferably from 0.0005 to 0.05. The divalent
metal salt may comprise a metal ion selected Zn2+, lvlgzl or Ca2+, or combinations thereof.
ln the following step iii) an anionic or amphoteric carboxymethyl cellulose (CMC) or a
derivative thereof is attached to the cellulosic fibres in the first pulp slurry. The CMC can be
attached to the cellulosic fibres by treating the pulp with CMC at a temperature of at least
50°C and in the specific conditions created during the alternative steps ii), i.e. at acidic
conditions or in the presence ofelectrolytes, i.e. in the presence of divalent metal ions.
I\/lethod for the CMC attachment is known in the prior art and can be performed as described
for example in one of the applicant's previous patents, EP1240389B1.
ln the following step iv) a metal salt comprising a multivalent metal ion selected from Alsl,
Zn2+, IVIgZÜ Ca” or mixtures thereof, is added to the first pulp slurry. The metal ion added to a
total molar concentration ofthe metals ion in the first slurry of from 0.0001 M to 0.5 M. If the
concentration ofthe divalent metal ions added in the step ii) is within the desired range, no
further addition of a metal salt is necessary. By adding the multivalent metal salt to the first
pulp slurry, which is never-dried, it is possible to provide a bulking structure for a cured pulp
product. The cured pulp product is obtained in the following curing step under acidic
conditions whereby the structure ofthe fibres is stabilized and thus a paper or paperboard
product with higher bulk can be provided. Therefore, it is possible to obtain low density paper
or paperboard materials.
The counter ion in the multivalent metal salt may be any suitable counter ion and can be for
example selected from Cl", NO3T or S042' or any other suitable counter-ion, which is dissociated
from the multivalent metal ion in water. Such salts are also often used in papermaking and are
suitable for the processes thereof.
Preferably, the amount of the added metal salt in step iv) is kept as low as possible so that the
quality of the pulp material is not degraded. Thus, the multivalent metal salt comprising a
metal ion is preferably added to the pulp to a molar concentration of from 0.0001-0.05 I\/I.
Preferably, the multivalent metal salt is an aluminium salt and is added to the first pulp slurry
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in addition to the divalent metal ions and to a total molar concentration of from 0.0001 M to
0.05 l\/l.
The pH of the first pulp slurry is adjusted after or before the addition ofthe metal salt
comprising the metal ion if necessary as described in the step v) of the process. lt is essential
that the pH is acidic during curing and the pH of the first pulp slurry should be from pH 3.5 to
pH 6.0. The adjustment can be performed by using an acid or base other than the metal salt
used in steps ii) and/or iv), e.g. by using sulphuric acid.
After the addition ofthe multivalent metal ions and the adjustment of the pH in step v) if
needed, the first pulp slurry is dewatered and cured under acidic conditions in the step vi) of
the process to provide a cured web, which is to be distinguished from a dried web obtained
from the final paper/paperboard process. The acidic condition during the curing in the step vi)
of the first pulp slurry further increases the bulk of a paper, paperboard, tissue paper, filter
paper, or fluff pulp made from the cured pulp product. This is caused by an increased
hornification of the cellulosic fibres when cured under acidic conditions and especially good
results have been obtained in the presence of AIS* ions. This means that the fibres become
stiffer in aqueous suspensions than non-treated fibres. The curing temperature is at least
60°C, and the first pulp slurry is cured until the moisture content is below 50%. Preferably, the
moisture content is below 30%, and most preferably below 15%. Normally, the pulp is cured
until a moisture content level of from 0 to 5% is obtained. Due to practical reasons, the pulp
often contains small amounts of moisture.
lt has also been noted that the curing temperature influences the bulk of the cured pulp
product, i.e. a lower density may be obtained by increasing the curing temperature. Therefore,
according to an embodiment of the invention, the curing temperature of the first pulp slurry
can be from about 60°C and up to about 150°C, preferably from 80 to 120°C, when the curing
is performed by means of heated air/steam or by means of steam heated drying cylinders.
Suitably, the first pulp slurry is cured for less than about 3 hours at the specific temperature.
The cured pulp product continues to cure when it is rolled into a web roll or when stacked into
bales of sheets, since the temperature of the cured pulp product decreases slowly, and this
curing time is also included in the curing period of less than about 3 hours.
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Alternatively or additionally to the drying by means of heated air or steam or steam heated
cylinders, the first pulp slurry can be cured by means of flash drying, also called swirl
fluidisizing. Such driers are known in the art and provided e.g. by the company GEA Process
Engineering A/S or Andritz AG. By using flash drying, the drying temperature can be higher
than when drying by means of heated cylinders, and the temperature can be of from 100 to
300°C, depending on the sensitivity ofthe first pulp slurry to the curing conditions. Also the
curing time can be shorter when flash drying is used. By flash drying a further bulking effect,
i.e. a higher bulk with lower density, may be obtained, and a free-flowing material may be
obtained. Further, the bulk of the first pulp product may be further increased.
Thus, in the ”dry process” the first pulp slurry containing the multivalent metal salt is cured
before re-slushing it in a paper- or paperboard making process. lt is thus possible to lower the
water retention value significantly during the paper or paperboard production. The pressing
efficiency can be improved significantly and a higher dry content after the press section can be
obtained and therefore less energy for drying is needed. The treatment suitably takes place in
a pulp mill, and the pulp is used in a non-integrated paper/board mill, and therefore the
resource efficiency will be much higher both in terms of material and energy efficiency at the
non-integrated paper/paperboard mill.
The cured web obtained in the step vi) can be used as such or e.g. rolled into a web roll having
a pre-determined web length. Optionally, in a step vii) the cured web of pulp can be cut into
sheets and the sheets are stacked to provide bales of pulp.
The cured pulp product may be used for the production of paper or paperboard, but may also
be used for the production of tissue paper, filter paper, or fluff pulp.
ln case of a non-integrated paper mill, it is possible to transport the cured pulp product to the
paper mill from the pulp mill in the form of bales, rolls or flakes. The cured pulp product is
then re-slushed in a headbox of a papermaking machine.
According to a further aspect, the present invention also relates to a process for the
production of paper or paperboard. After collecting the cured web in a suitable manner in the
step vi) or vii) described above, the cured web is provided to the papermaking process in a
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process step a). The providing is illustrated by two broken lines between the process steps i) to
vi) or vii) and the process steps a) to d) in Fig. 1.
The cured pulp product is then subjected to re-slushing in step b) to provide a second pulp
slurry. The second slurry is then dewatered in the step c) and a web of paper or paperboard is
provided. The web is then dried in a step d) and thus a dried, bulky web of paper or
paperboard that is suitable for use as a packaging material is obtained. The paper or
papermaking process can be performed in a traditional way, and dry contents, additives and
other papermaking process parameters known in the art can be used.
Since the cellulosic fibres become stiffer due to the treatment in steps i)-vii) above in aqueous
suspensions after re-slushing, the fibres swell less during the re-slushing of the cured pulp
product. This leads to webs that are easily dewatered during the papermaking process. This is
a huge advantage and makes the process energy efficient while higher bulk can be obtained.
ln the paper or paperboard material comprising the bulking fibres treated with a multivalent
metal ion there may be a risk that the mechanical properties (e.g. z-strength for instance
measured according to SCAN-P 80:98) are weakened. Thus, in order to enhance the strength
of paper/board made from bulking fibres, there are several different groups of suitable dry
strength aids including, but not limited to, nanocellulosic materials, such as microfibrillar
cellulose, cellulose nanofibrils, cellulose filaments, nanocrystalline cellulose, fines and fines
enriched pulps, starch and gum derivatives, synthetic copolymers with acrylamide, such as
acrylic acid, vinyl pyridine, 2-aminoethyl methacrylate, diallyl-dimethyl ammonium chloride,
dimethyl-amino-propylacryl amide, diamine ethyl acrylate, styrene and glyoxalated
polyacrylamides. The latter group is also suitably copolymerized with cationic monomers. Wet
strength resins such as urea-formaldehyde resins, melamine-formaldehyde resins or
polyamide-polyamine-epichlorohydrine resins are also useful in order to enhance the dry
strength of bulking fibres. Such dry strength aids or wet strength resins are suitably added to
the second pulp slurry during paper or paperboard production, whereby the strength of the
final paper or paperboard product can be improved.
l
'Wet rocess"
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A second embodiment of the present invention is illustrated in Fig. 2. This process relates to a
process for the production of paper or paperboard suitable for use as a packaging board and is
also called a ”wet process", since the curing step (vi) ofthe first embodiment is not
performed. The steps I, ll and lll in the process are similar to the process steps i) to iii) in Fig. 1
and reference is made to the description above in connection with Fig. 1. ln short, the steps I
to lll comprise:
I. providing a first aqueous pulp slurry comprising cellulosic fibres and having a
pulp consistency of from 0.1 to 40 % by weight, calculated as dry weight of the
cellulosic fibres in the first pulp slurry;
ll. adjusting the pH ofthe first pulp slurry to a range from pH 1.5 to pH 4.5, or
alternatively treating the first pulp slurry with a metal salt containing divalent
metal ions selected from Zn", Mg2+, Ca” or mixtures thereof, to a total molar
concentration of the metal salt of from 0.0001-O.5 M in the first pulp slurry
lll. attaching an anionic or amphoteric carboxymethyl cellulose (CMC) or a
derivative thereof to the cellulosic fibres in the first pulp slurry by treating the
first pulp slurry with the CMC at a temperature of at least 50°C;
After the steps I to lll, in the following step IV, the cellulosic fibres with the attached CMC in
the first pulp slurry is ion-exchanged to counter-ions with high valency. This means that a
multivalent metal salt comprising aluminium Al3+- metal ion is added to the first pulp slurry to
a total molar concentration from 0.0001 M to 0.5 M, whereby an ion-exchange occurs.
Without binding to any specific theory, it is believed that when the ion-exchange occurs, the
fibre to fibre friction increases significantly in the presence of A|3+-ions on the surface of the
fibres. The higher friction between the fibres in the wet state will partly prevent sheet
consolidation and result in a paper/paperboard product with a higher bulk. lt is also believed
that the fibres thus form a network of fibres and this network can be maintained during a
drying process in a papermaking process.
After the addition ofthe aluminium salt, the first pulp slurry is provided to a papermaking
process in step V. The paper making process may be of any known kind and chemicals and
other papermaking parameters suitable for the process in question can be used. ln a usual
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manner, the first pulp slurry is then dewatered in step VI) to provide a web and finally, in the
step VII) the web is dried to provide a web of paper or paperboard.
ln a similar manner as mentioned above, the process may further comprise adding a dry
strength aid or a wet strength resin to the first pulp slurry. The same aids or resins as
mentioned above can be used for the purpose.
The present invention also relates to a paper or paperboard product suitable for use as a
packaging material which is obtained by the processes described above. lt is possible to obtain
a high quality paper or paperboard with low density having a structural density according to
SCAN-P-88:01 of from 150 to 600 kg/m3. The paper or paperboard product is suitably used as a
packaging material. Preferably, the paper or paperboard product can be used as a middle layer
in a paperboard to provide increased bulk for the paperboard product.
The present process is suitable for use in both pulping and papermaking mills/factories that
are integrated or non-integrated, since the curing step after metal-ion addition is not essential
for the bulking effect in the second embodiment ofthe invention.
The invention will now be further described and illustrated in the following examples.
EXAMPLES
The following exampled illustrate the effects of the present invention, but should not be
regarded as limiting the scope of invention in any way.
Example 1
A never-dried bleached softwood kraft pulp was treated with 20 and 40 mg/g amphoteric CI\/IC
having degree of substitution of anionic groups= 0.48 and degree of substitution of cationic
groups = 0.027, whereby the amphoteric C|\/IC has a total net anionic charge, whereby the
amount of carboxylic groups on the surface of fibres can be enhanced. The pulps were treated
with the CMC under conditions given in Table 1 below.
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Table 1 CIVIC Grafting conditions.
Water type Deionised water
Pulp concentration 25 g/litre (2.5% by weight)
Electrolyte concentration (CaClz) 0.05 M
CMC addition 20 mg CIVIC/g fibre, or
40 mg CMC/g fibre
pH 8
Temperature during CMC 120 °C
treatment
Time for CMC treatment 2 hrs
The amount of attached CMC was quantitative, i.e. all CI\/IC became attached to the fibre
surface. After the CMC-attachment, the pulp was treated with AICI3 to a total molar
concentration of 0.005 M AICIS and the pH was adjusted to 4.0 and 5.0, respectively. After the
pH adjustment, the pulp was dewatered on a Buchner funnel to a solids content of around
20%. The pulp was then cured at 120°C for 2 h (oven drying), after which the pulp was re-
slushed and formed into sheets in accordance with ISO 5269-1:2005, except that the sheets
were pressed at 400 kPa for 5 min.
The water retention value (WRV) was measured according to SCAN-C62:00 before the sheet
forming. The structural density (SCAN-P 88:01) was then determined on the prepared and
pressed sheets. The effects on the WRV and resulting sheet density obtained by the process,
also referred to as a ”dry process” are shown in Fig. 3 and Fig. 4 respectively. ln the process
amphoteric CMC is attached to the cellulosic fibres in an amount of 20 mg/g and 40 mg/g.
From Fig. 3 it can be concluded that ifthe CMC is attached to the cellulosic fibres and the
fibres are transferred to their aluminium form and dried under acidic conditions, the water
retention value can be lowered and thus improved. lt can also be concluded that the WRV
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decreases and thus improves when the pH decreases. Thus, the lower the pH value is, the
lower the obtained WRV is.
From Fig. 4 it can be concluded that if the CMC is attached to the cellulosic fibres and the
fibres are transferred to their aluminium form and dried under acidic conditions a higher bulk
of the sheets is obtained compared to pulps not treated with CMC. lt can also be concluded
that the density decreases leading to improved bulk when the pH decreases.
Example 2
This example shows the effects of different treatment temperatures and times on WRV, which
are believed to occur due to hornification.
Never-dried bleached softwood kraft pulp was treated with 20 mg/g amphoteric CMC having a
degree of substitution of anionic groups= 0.48 and degree of substitution of cationic groups =
0.027, wherein the CI\/IC has a net anionic charge, whereby the amount of carboxylic groups
on the surface of fibres can be enhanced. The pulps were treated with the CMC under
conditions given in Table 1 above and in Example 1. The fibres were then transferred to their
aluminium form and cured at different temperatures, 60°C, 80°C, and 120°C. After the curing
the pulps were re-slushed and their WRV values according to SCAN-C62:00 were determined.
Fig. 5 shows in a graph the effect of the curing (oven curing) temperature on WRV due to
hornification of a pulp treated with 20 mg/g amphoteric CMC pulp in its Al-form (i.e. a total
molar concentration of Al-ions 0.005 M) and pH 3.5.
lt can be concluded that the higher the curing temperature is, the more the WRV decreases
and thus improves the bulk of the paper/board.
Example 3
A never-dried bleached softwood kraft pulp was treated with 20 mg/g amphoteric CMC having
a degree of substitution of anionic groups = 0.48 and a degree of substitution of cationic
groups = 0.027, and thus having a net anionic charge, whereby the amount of carboxylic
groups on the surface of fibres can be enhanced. The treatment was performed under the
conditions given in Table 1 above and Example 1. After the treatment the pulps were brought
10
15
20
25
25
in contact with different metal ion salts (i.e. electrolytes; as chloride salts) for 20 min at a total
molar concentration of the salts in the pulp slurry as follows:
Nafi 0.005 ivi;
cazfi 0.005 |v|
Mgzt; 0.005 |v|
zn 2% 0.005 |v|
AP? 0.005 |v|
The pulps were then cured at 120° C for various times and re-slushed, after which the WRV
was determined. The results are shown in Fig 6.
lt can be concluded that when the valency of the metal ion increases, the WRV decreases and
thus improves the bulk of the paper/board. Therefore, e.g. much lower WRV values were
obtained with Al3+ metal ions than with Na+ metal ions.
Example 4
This example illustrates that it is not always necessary to cure the pulp in order to enhance the
bulk of formed sheets and that bulk can also be obtained by the treatment according to the
”wet process” as described above. lt is possible to attach CMC (anionic) or amphoteric CI\/IC,
whereby the amount of carboxylic groups on the surface of fibres can be enhanced. Hence, a
pulp slurry of unbeaten bleached softwood kraft pulp was treated with 20 mg/g fibre of
anionic CI\/IC (degree of substitution = 0.4, Aquasorb A-500, Hercules, Sweden) under the same
conditions as shown in table 1 above in connection with Example 1.
Before the attachment of the CMC the pulp was set to its calcium form. The pulp was given an
acidic treatment at pH 2, after which the pulp was washed with deionized water and the pH
was increased to pH 8, again washed with deionized water and treated with a 101 M CaCIZ
solution and then finally washed with deionized water.
The pulp was then mixed with the CIVIC solution and with CaClz. The pH was adjusted to 8
using NaOH. The mixture was then inserted in an autoclave. The autoclave was heated up
under constant agitation in a glycol bath which had a constant temperature of 120 °C. After
10
26
the two hour long attachment process, the pulp was washed with deionised water on a
Buchner funnel until the conductivity in the filtrate was below 5 uS/cm.
The results from the treatment are shown in Table 2. The total amount of the attached CMC
was calculated from the total charge density increase to be 20.6 mg/g (+/- 1 mg/g), that is, the
attachment efficiency can be considered as quantitative. The surface selectivity of the
attachment, i.e. the amount of charges accessible on the surface of fibres as determined by
polyelectrolyte titration using high molecular weight poly-DADMAC (poly-Dia|ly|DiMethy|-
AmmoniumChloride was found to be 87.7 %, i.e. most of the CI\/IC was being attached onto
the surface of the fibres. As reference an untreated pulp washed to its Cazl form was used.
The method has been described by Horvath A E, Lindström T and Laine J. Langmuir, 22(2)
(2006), 824-830.
Table 2. Total and surface charge of reference pulp and pulp with attached CMC (20 mg/g)
pulp.
Pulp Total Charge Surface Charge ratio
(eqv./g) Charge (surface/total)
(eqv-/sl
Reference pulp
(Untreated pulp
washed to its Ca2+ 395 16 004
form)
CMC grafted pulp 83.6 37.2 0.44
10
15
20
27
The pulp treated with CMC 20 mg/g fibre was transferred to its Na+, Ca2+ and A|3+-form,
respectively. Different structural densities were obtained by forming sheets in accordance
with ISO 5269-1:2005, except that different pressing levels were used. Each sheet was pressed
for 5 minutes with different pressing levels, respectively (50, 100, 200, 400, 600, and 800 kPa).
Fig. 7 shows a tensile strength index (ISO 1924-3: 2005) versus structural density of paper
sheets pressed to different densities. The pulps were grafted with 20 mg/g CMC and then
transferred to different ionic forms (Na+, Cap, A|3+) together with a reference pulp without any
attached CMC in its Can-form.
Fig. 7 shows how the tensile strength index of reference sheets and sheets (ISO 5269-1:2005)
made from the bleached kraft pulp with the attached CMC is affected by the ionic form of the
pulp. Apart from the strength development, the sheets in their Na+-form and Cazïform have
approximately the same sheet density irrespective of pressing pressure, whereas the sheets in
their aluminium form have significantly lower sheet density. This example shows that it is
possible to make bulky sheets without curing before forming sheets by transferring paper
sheets with attached CMC to their Algïform before drying. However, curing of the pulp to
induce hornification is not a requirement, but stronger bulking effect can be achieved by the
”d ry procedure".
lt is clear to the skilled person in the art that the invention may be varied within the scope of
the appended claims. The examples and embodiments above are not intended to limit the
scope ofthe invention in any way. lnstead the invention may be varied within the scope of the
appended claims.
Claims (31)
1. Process for the production of a cured pulp product suitable for use in the production of paper, paperboard, tissue paper, filter paper or fluff pulp, comprising the steps of: i) in) vi) providing a first aqueous pulp slurry comprising cellulosic fibres and having a pulp consistency of from 0.1 to 40 % by weight, calculated as dry weight of the cellulosic fibres in the first pulp slurry; adjusting the pH of the first pulp slurry to a pH of from 1.5 to 4.5, or alternatively treating the first pulp slurry with a metal salt containing divalent metal ions selected from Zn2+, Mg", Ca” or mixtures thereof, to a total molar concentration of from 0.0001 to 0.5 M in the first pulp slurry; attaching an anionic or an amphoteric carboxymethyl cellulose (CMC) or a derivative thereof to the cellulosic fibres in the first pulp slurry by treating the pulp slurry with the CMC at a temperature of at least 50°C; adding to the first pulp slurry a metal salt comprising A|3+ ions at a total molar concentration of from 0.0001 M to 0.5 M in the first pulp slurry, or alternatively controlling the concentration of the divalent metal ions in the pulp slurry and adjusting the total molar concentration of the divalent metal ions selected from Zn2+, Mg2+, Ca2+ or mixtures thereof to a range of from 0.0001 M to 0.5 M in the first pulp slurry, ifthe total molar concentration is not within the range of from 0.0001 M to 0.5 M in the first pulp slurry; controlling the pH and adjusting the pH of the first pulp slurry to a pH of from pH 3.0 to pH 6.0 if the pH is not within the range of from pH 3.0 to pH 6.0; dewatering and curing the first pulp slurry at a temperature of at least 60°C and thus provide a cured pulp product.
2. Process according to claim 1, wherein in the step vi) the first pulp slurry is cured by means of flash drying at a temperature of from 100°C to 300°C, preferably from 150°C to 270°C and most prefera bly from 180°C to 240°C. 10 15 20 25 30 10. 29 Process according to claim 2, wherein the curing time is less than 5 minutes, preferably less than one minute.
Process according to claim 1, wherein in the step vi) the first pulp slurry is cured at a temperature of from 60 to 150°C by means of heated air or steam.
Process according to claim 4, wherein in the step vi) the cured pulp product is provided in the form of a cured web.
Process according to claim 5, wherein the process further comprises a step vii) comprising cutting the cured web of pulp into sheets and stacking the sheets to bales of pulp.
Process according to any one of the preceding claims, wherein in the step vi) the cured pulp product is cured until a moisture content of below 50%, preferably below 30% and most preferably below 15%, based on the total weight ofthe cured pulp product, is obtained.
Process according to any one of the preceding claims, wherein in the step iv) the metal salt is a metal salt containing Ala* ions which is added to the first pulp slurry to a total molar concentration of from 0.0001 M to 0.05 M in the first pulp slurry.
Process according to any one of the preceding claims, wherein the pulp consistency of the first aqueous pulp slurry is of from 0.5% to 30%, preferably of from 1% to 20%, calculated as dry weight ofthe cellulosic fibres in the first pulp slurry.
Process according to any one of the preceding claims, wherein the CI\/IC is amphoteric and has a cationic molar substitution degree of from 0.00001 to 0.4 and an anionic molar substitution degree of from 0.3 to 1.2, and wherein a net charge ofthe CI\/IC is anionic.
10 15 20 25 30 30
11. Process according to any one of the preceding claims 1-9, wherein the CI\/IC is anionic and has an anionic molar substitution degree of from 0.3 to 1.2.
12. Process according to any one of the preceding claims, wherein the amount of the anionic or amphoteric CMC attached during the treatment is of from 1 to 100 mg/g, based on the weight of the cellulosic fibres in the first pulp slurry.
13. Process according to any one of the preceding claims, wherein the first aqueous pulp slurry comprises a pulp selected from a kraft, soda, sulfite, mechanical, thermomechanical, semi-chemical or chemi-thermomechanical pulp, recycled pulp or mixtures thereof.
14. A cured pulp product obtained according to the process of any one of claims 1-13.
15. Process for the production of paper or paperboard comprising the steps of: a. providing a cured pulp product according to claim 14 to a paper making process; b. re-slushing the cured pulp product to provide an aqueous second pulp slurry; c. dewatering the aqueous second pulp slurry to provide a web of paper or paperboard; d. drying the web of paper or paperboard to provide a dried web of paper or paperboard.
16. Process according to any claim 15, wherein the process further comprises adding a dry strength aid or a wet strength resin to the second pulp slurry.
17. Process for the production of paper or paperboard comprising the steps of: I. providing a first aqueous pulp slurry comprising cellulosic fibres and having a pulp consistency of from 0.1 to 40 % by weight, calculated as dry weight of the cellulosic fibres in the first pulp slurry; ll. adjusting the pH of the first pulp slurry to a pH of from 1.5 to 4.5, or alternatively treating the first pulp slurry with a metal salt containing divalent 10 15 20 25 30 18. 19. 20. 21. 22. 31 metal ions selected from Zn2+, l\/|g2+, Cazl or mixtures thereof, to a total molar concentration of the metal salt of from 0.0001 to 0.5 M in the first pulp slurry; |||. attaching an anionic or amphoteric carboxymethyl cellulose (CMC) or a derivative thereof to the cellulosic fibres in the first pulp slurry by treating the first pulp slurry with the CMC at a temperature of at least 50°C; IV. adding to the first pulp slurry a metal salt comprising an Al3+ metal ion to a total molar concentration of from 0.0001 M to 0.5 M in the first pulp slurry whereby an ion-exchange occurs; V. providing the first pulp slurry to a papermaking process and thus provide a second pulp slurry; VI. dewatering the second pulp slurry to provide a web of paper or paperboard; VII. drying the web of paper or paperboard to provide a dried web of paper or paperboard. Process according to claim 17, wherein the first pulp slurry comprises a pulp selected from a kraft, soda, sulfite, mechanical, thermomechanical, semi-chemical or chemi- thermomechanical pulp, or mixtures thereof. Process according to any one of the claims 17 or 18, wherein the pulp consistency of the first pulp slurry is of from 0.5 to 30%, preferably of from 1 to 20%, calculated as dry weight of the cellulosic fibres in the first pulp slurry. Process according to any one of the preceding claims 17-19, wherein the CMC is amphoteric and has a cationic molar substitution degree of from 0.00001 to 0.4 and an anionic molar substitution degree of from 0.3 to 1.2. Process according to any one of the preceding claims 17-19, wherein the CI\/IC is anionic and has an anionic molar substitution degree of from 0.3 to 1.2. Process according to any one of the preceding claims 17-21, wherein the amount of the anionic or amphoteric CI\/IC attached during the treatment is of from 1 to 100 10 15 20 25 23. 24. 25. 26. 27. 28. 29. 30. 31. 32 mg/g, based on the weight of the cellulosic fibres in the first pulp slurry. Process according to any one of the preceding claims 17-22, wherein the multivalent metal salt comprising an Al3+ metal ion is added to the pulp in the step IV) to a total molar concentration of from 0.0001 to 0.05 M. Process according to any one of the preceding claims 17-23, wherein the process further comprises adding a dry strength aid or a wet strength resin to the first pulp slurry. Paper or paperboard obtained by the process according to any one of claims 15-24. Paper or paperboard according to claim 25 having a structural density of from 150 to 600 kg/ms according to SCAN-P-88:01. Use of the paper or paperboard of claim 25 or 26 as a packaging material. Use of the paper or paperboard product of claim 25 or 26 as a middle layer in a paper board. Use of the cured pulp product according to claim 14 for the production of fluff pulp. Use of the cured pulp product according to claim 14 for the production of tissue paper. Use of the cured pulp product according to claim 14 for the production of filter paper. Ansökningsnummer/ Patent application No: 1550654-6 I följande bilaga finns en översättning av patentkraven till svenska. Observera att det är patentkravens lydelse på engelska som gäller. A Swedish translation of the patent elaims is enclosed. Please note that only the English claims have legal effect. Patentkrav i. Förfarande för irarnstaiining av en beiiandiatt rnaeeapretitii-:t för användning vid frarnetaiirting av papper, kartong, ntjukpapper, tiiterpapper etter titrtirrtaeea, innefattande stegen att: i) tiiinandanàiia en företa vattenhaitig maseasuepeneien innefattande ceiitiiesanaitiga titarer och eern har en maasakensistens av från Gji tiii 40 vikt-Wi, räknat som de eeiiuiosaiiaitiiia fiörernae torrvikt i den företa rnaesasuepeneionen; ii) justera den företa rnaesaeiiepensienene pi-i tiii ett ett från 15-45, etter aiternativt benandia den första rnassasuepensionen med ett nietaiisalt innenåiiartde divalenta rnetaiiioner vaida från Znz i* iiligz i* Ca? i eiier iiiandningar därav, tiii en totai rneikoncentratiön av CLQOüi tiii 9,5 tvi i den företa rnaeeaetienertsiönen; iii) fästa en anjeniek eiiei' en amtetei' karbexirrtetyieeiiiiiosa (Git/IC) eiier ett derivat därav tiil de ceiiuiosahaitiga fibrerna i den företa rnaeeaeuepensionen genom att benandia rnaseaeuepensinnen med Git/EC vid en temperatur av åtminstone 50°C; iv) tiiieötta tiii den företa rnaeeaeiiepensiönen ett metaiisaii: innefattande Aiä i -iener tiii en tötai rrioiitoneentratien av 0,00% it/i tiii (1,5 ivi i den första maesaeueperisiönen, eiier aiternativt kontroiiera koncentrationen av tvavärda rnetaiiioner i inaseastisnensienen een justera den totala ntoikoncentratienert av ttravarda inetaiijonei' vaida fràn Znz it/igzi", Caz i' eiier biandningar därav tiii ett område fran 613001 ivi tiii 9,5 tvi i den företa rnassasuspensionen, om den tötaia rnöikorteentrationen inte ar inom intervaiiet från 033691 tvi tiii 9,5 ivi i den första ritaseaetieraeneionen; v) kentroiiera pi-i och justera pH i den företa niassaeuepeneienen tiii ett pH 'från pH 3.0 tiii pH 6.9, om pi-i-värtiet inte är inom intervaiiei iran pH 3,Û tiii pH tšß; vi) avvattna een beitandia den företa rnaseasusperisionen vid en tentperatur av minst fiO°C och därmed tiiinandanšiiia en benandiad massaprediikt.
2. Förtarande eniigt krav i. varvid i steget vi) benandiae den företa rnaseastiepeneienen med fiingtörknirtg vid en ternperaturfrån iQtfC tiii 390%), företrädesvis från 159%) tiii 2?G°C och rnest föredraget från 'iSOÛC tiii 246%).
3. Föriarande eniigt krav 2, varvid benandiingetiden är mindre än 5 minuter, företrädesvis mindre än en rninut.
4. Förfarande eniigt krav t, varvid i steget vi) benandias den första niaeeaeuepensienen vid en temperatur från öü tiii 150%; rned uppvärmd itrit eiier ånga.
5. Förfarande eriiigt krav 4, varvid i steget vi) tiiihandanaiie den benandiade inaesaprodukten i farm av en beiiandiad bana. fi. Förfarande eniigt krav 5, varvid förfarandet vidare innefattar ett steg vii) innefattande att skära den benandiacie rnassabanan tiii ark och att stapia arken tiii massabaiar.
7. Förfarande eniigt något av föregående krav, varvid i steget vi) beitandiae den behandiade niassaprodukten tiiie en fuktnait av under 56%, företrädesvis Linder 39% och niest företrädesvis under 15%, baserat på den ietaia vikten av täten benandiade maseaprodtikteii, erhàiies.
8. Förfarande eniigt något av föregående krav, varvid i steget iv) är rnetaiisaitet ett rnetaiisait innehàiiande A53* »joneig som tiiiaëtts i den första massasuspensioneit tili en totai moikoncentratieiw från iLOOOt ivi tiii 0,95 ivi i den första rnassaeuspeneionen.
9. Förfarande eniigt något av föregående krav, varvid den företa vattennaitiga niassastisiaensionens inassakonsietens är från 05% tiii 3094,, företrädesvis från 1% tiEi 209%, räknat som de ceiiuiosahaitiga fibrernas torrvikt i den företa ntassasnspensieiwen. 1G. Förfarande eniigt något av föregående krav, varvid CiviC ar arnfoter och har en katjoriiek moiar substitutinnsgrad av 1106001 »(3,4 och en anjoniek moiär substitutinnsgrad från 0,3 tiii 1,2 och varvid en netteiaddniatg av CiviC är anjeniek. ti. Förfarande enligt något av föregående krav 'i-9, varvid CiviC är anjenisk edit nar en anjdniak rnoiër eubstitutianegrad från 0,3 iiii 1,2.
12. Förfarande eniigt nagot av föregående krav, varvid mängden av det anioniska eiier amfotera CiviC som fästs under betiandiingen är 'från “i iiii 100 rngig, baserad på de ceiiuiosanaitiga fibrernas vikt i den första rneeeasuepensionen.
13. Förfarande eniigt nagot av föregående krav, varvid den första vattennaitiga rnassasuspeneionen innefattar en massa vaid från auifat, Soda, suttit, mekanisk, tennernekariisk, naivkefniek eiier kerniierrnornekaniek rnassa, retunnasea eiier biandnirigar' därav.
14. En beiiandiad rnassapradiikt som eriiåiis eniigt förfarandet eniigt något av krav 1-13.
15. Förtarande för tramstattning av papper etter kartong innefattande stegen: a. ttttnandanatta en benandtad anassapredtikt entigt patentkrav 14 i en papperstittverkningsproeess; b. ateruppsta den behandtade massaprodtrttten för att tittnandanàtta en vattennatttg andra rnassasuspension; e. avvattna den vattennattiga andra rnassasuspeneieneit för att tittnandanatta en bana av papper etter kartong; d. torka banan av papper etter kartong för att tittnandanåtta en torkad bana av papper etter kartong.
16. Föifarande enttgt något krav 15, varvid förfarandet vidare innefattar att tittsätta ett torrstyrkemedet etter vatetyrttettarts t den andra rnassasuspeneiönen.
17. Förtarande för tramstättntrtg av papper etter kartong innefattande stegen: t. ttttttandattatta en första vattentiattig ntassasttspensidn innefattande eettutesattattiga fibrer sent har en rnaseakonsietene från 9,1 titt 4G vitttßï/å, räknat som eettutosattattiga ttbrernas torrvikt t den första maseasuepeatetoneat; tt. justera den första massaeuspensionens pt-t titt 154,5, etter alternativt ttettandta den första rnaseaeuspensionert rned ett metatteatt innenàttande divatenta rnetattioner vatda från Znz tvtg? Cap, etter tstandningar därav, titt metattsattets totata rnetttoneentration tran 0,09% titt G5 tvi i den första ntassasuspertsienen; ttt. fästa en anjönisk etter amföter' karboxirnetytcettutosa tCtvtC) etter ett derivat därav titt cettutdsanattiga fibrerna i den första massasuspensierten genern att benandta den första rnassasuspensionen rned GMC vid en temperatur av åtminstone 50%; IV. tittsëtta i den första ntassasttspenaionen ett ntetattsatt innefattande en Att” ntetattjert titt en totat rnetkoneentratton från OitOOt tvt titt (3,5 tVt t den företa rnaesastispensienen varigenom jonbyte sker; V. 'tittnanttanatta den Första massasttspensionen i en papperstittverkntngspreeees och därigenom ttttnandattatta en andra rnaeaasuspertsion; Vi. avvattna den andra massaeuspeneionert för att tittttandattátta en bana av papper etter kartong; Vtt. torka banan av papper etter kartong för att 'tittnanttanatta en torkad bana av papper etter kartong.
18. Förfarartde entigt krav 17, varvid den första nfiassasuspensionen innefattar en massa vatd från sulfat, soda, suttit, mekanisk, termomekanisk, nåtvkemisk etter kerniterrnornekanisk massa, etter btartdningar darav.
19. Förfarande enligt något av krav 17 etter 18, van/id den första massasuspertsionens rnassakonoentratien är från 0,5 tiii 399%, företrädesvis från t tiii 299%, räknat som de oeiiutosatiattiga tibrernas torrvikt i den första rnåssasuspensionen.
20. Förfarande entigt nagot av ite föregående krav 174 9, varvid GMC är arnfoter och nar en katjenisk matar aubstitutionsgrad av från íLOÛÛÛt tiii (3,4 och en anjonisk meiär stibstitutionsgrad 'från Üß 'tiil 1,2.
21. Förtarande enligt något av de föregående krav 1749, varvid GMC är' anjonisk och nar en anionisk niotår stibstitutionsgrad från (3,3 tiil 1,2.
22. Förfarande enligt nagot av de föregående krav tY-Zt, vart/id rnängden av det artioniska etter amtotera Gti/EC fäst under behandlingen är från "t tili 100 rngig, baserat på vikten av de eeliutosanaitiga fibrerna i den första massasuspensionen.
23. Förtarande eniigt något av de föregående krav 17-22, varvid det ntutttvaienta ntetatisaitet som innefattar' en AEG f (220001 titt 0,65 tvi. rnetaitjon titisatts i massan i steget EV) tiii en totai motkonoentration av
24. Förfarande enligt något av de föregående krav tY-23, varvid förfarandet vidare innefattar tittsättning av ett torrstyrkettiätprnedel etter ett vàtstvrketiarts i den första rnassastispensidnen.
25. Papper etter kartong som erttåtis genorn förfarandet eniigt något av kraven 1524.
26. Papper etter kartong enligt krav 25 sent har en struktureit densitet från 150 tiii 609 kg/mg eniigt SCAN-thßßzüt.
27. Användning av papper etter kartong enligt krav 25 etter 26 som förpackningsrnateriat.
28. Användning av papners- etter kartonggrodukt eniigt krav 25 etter 26 som ett rneitanskikt i en kartong.
29. Användning av den behandiade anassaprociuktezw enšâgt patæntkrav 14 för frarnstäiíning av 'fiu'ífmassa,
30. Användning av dæn behandiade massaprodukïen enšigt patentkrav 14 för framstäišning av mjukpapper.
31. Användning av den behandiade massaprodukten enšigt patentkrav 14 för *írarnsïäiinšng av fiiterpapper.
Priority Applications (9)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE1550654A SE538863C2 (sv) | 2015-05-22 | 2015-05-22 | Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof |
PCT/SE2016/050460 WO2016190801A1 (en) | 2015-05-22 | 2016-05-19 | Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof |
CA2986087A CA2986087A1 (en) | 2015-05-22 | 2016-05-19 | Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof |
JP2017560761A JP2018515696A (ja) | 2015-05-22 | 2016-05-19 | 紙または板紙の製造方法、得られた紙または板紙製品およびその使用 |
CN201680029507.7A CN107849824A (zh) | 2015-05-22 | 2016-05-19 | 用于生产纸张或纸板的方法、得到的纸张或纸板产品及其用途 |
US15/575,410 US20180155875A1 (en) | 2015-05-22 | 2016-05-19 | Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof |
BR112017024581A BR112017024581A2 (pt) | 2015-05-22 | 2016-05-19 | processo para produção de papel ou papelão, produto de papel ou papelão obtido e usos do mesmo |
EP16800385.3A EP3298197A4 (en) | 2015-05-22 | 2016-05-19 | PROCESS FOR PRODUCING PAPER OR CARDBOARD, PAPER PRODUCT OR CARTON OBTAINED, AND USES THEREOF |
CL2017002959A CL2017002959A1 (es) | 2015-05-22 | 2017-11-21 | Proceso para la producción de papel o carton, productos obtenidos a base de papel o carton y sus usos relacionados. |
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SE1550654A SE538863C2 (sv) | 2015-05-22 | 2015-05-22 | Process for the production of paper or paperboard, paper or paperboard product obtained and uses thereof |
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SE1550654A1 true SE1550654A1 (sv) | 2016-11-23 |
SE538863C2 SE538863C2 (sv) | 2017-01-10 |
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US (1) | US20180155875A1 (sv) |
EP (1) | EP3298197A4 (sv) |
JP (1) | JP2018515696A (sv) |
CN (1) | CN107849824A (sv) |
BR (1) | BR112017024581A2 (sv) |
CA (1) | CA2986087A1 (sv) |
CL (1) | CL2017002959A1 (sv) |
SE (1) | SE538863C2 (sv) |
WO (1) | WO2016190801A1 (sv) |
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US20170073902A1 (en) | 2014-04-23 | 2017-03-16 | Hewlett-Packard Development Company, L.P. | Packaging material and method for making the same |
SI3121332T1 (en) | 2015-07-20 | 2018-06-29 | Mayr-Melnhof Karton Ag | Multilayer carton material and a process for the production of multi-layer cardboard material |
US11162223B2 (en) | 2017-03-30 | 2021-11-02 | Kimberly-Clark Worldwide, Inc. | Fibrous structures comprising acidic cellulosic fibers and methods of manufacturing the same |
FI20175545A1 (sv) * | 2017-06-13 | 2018-12-14 | Upm Kymmene Corp | Förfarande för att öka dragstyrkan hos massa |
JP6967977B2 (ja) * | 2018-01-19 | 2021-11-17 | アイカ工業株式会社 | 不燃化粧パネル |
BR112020005283B1 (pt) | 2018-04-13 | 2021-08-03 | Eldorado Brasil Celulose S/A | Processo para a fabricação de um material de trama melhorado mediante a medição e o ajuste in-situ de concentrações de íons |
EP3887596A4 (en) * | 2018-11-29 | 2022-08-24 | RISE Innventia AB | METHOD FOR PRODUCTION OF HOLOCELLULOSE AND RESISTANT AGENT FOR PAPER, METHOD FOR PRODUCTION OF PAPER, PRODUCT PAPER AND USE OF PRODUCT PAPER |
GB2582368B (en) * | 2019-03-21 | 2021-03-17 | Unwasted Ltd | Process and system for manufacturing a fibreboard from corrugated waste materials |
SE543640C2 (sv) * | 2019-09-04 | 2021-05-11 | Stora Enso Oyj | Fluff pulp from oxygen delignified pulp |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
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SE9903418D0 (sv) * | 1999-09-22 | 1999-09-22 | Skogsind Tekn Foskningsinst | Metod för att modifiera cellulosabaserade fibermaterial |
SE0202652D0 (sv) * | 2002-09-09 | 2002-09-09 | Skogsind Tekn Foskningsinst | Method for sizing of paper or paperboard |
AU2003221374A1 (en) * | 2003-03-13 | 2004-09-30 | Oji Paper Co., Ltd. | Process for producing paper |
JP2005163253A (ja) * | 2003-11-14 | 2005-06-23 | Nippon Paper Industries Co Ltd | 嵩高中質印刷用紙 |
SE0400396D0 (sv) * | 2004-02-20 | 2004-02-20 | Skogsind Tekn Foskningsinst | Method for modifying lignocellulosic material |
SE0401600D0 (sv) * | 2004-06-18 | 2004-06-18 | Stfi Packforsk Ab | Method for manufacturing paper or similar |
JP2008088582A (ja) * | 2006-09-29 | 2008-04-17 | Mitsubishi Paper Mills Ltd | 低密度印刷用紙 |
EP1920787A3 (en) * | 2006-10-02 | 2010-03-17 | Weyerhaeuser Company | Crosslinked carboxyalkyl cellulose fibers having permanent and non-permanent crosslinks and methods for its preparation |
SE0800807L (sv) * | 2008-04-10 | 2009-10-11 | Stfi Packforsk Ab | Nytt förfarande |
EP2596168B1 (en) * | 2010-07-20 | 2023-06-14 | International Paper Company | Composition containing a multivalent cationic metal and amine-containing anti-static agent and methods of making and using |
-
2015
- 2015-05-22 SE SE1550654A patent/SE538863C2/sv not_active IP Right Cessation
-
2016
- 2016-05-19 CA CA2986087A patent/CA2986087A1/en not_active Abandoned
- 2016-05-19 CN CN201680029507.7A patent/CN107849824A/zh active Pending
- 2016-05-19 BR BR112017024581A patent/BR112017024581A2/pt not_active Application Discontinuation
- 2016-05-19 EP EP16800385.3A patent/EP3298197A4/en not_active Withdrawn
- 2016-05-19 US US15/575,410 patent/US20180155875A1/en not_active Abandoned
- 2016-05-19 JP JP2017560761A patent/JP2018515696A/ja not_active Withdrawn
- 2016-05-19 WO PCT/SE2016/050460 patent/WO2016190801A1/en active Application Filing
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2017
- 2017-11-21 CL CL2017002959A patent/CL2017002959A1/es unknown
Also Published As
Publication number | Publication date |
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SE538863C2 (sv) | 2017-01-10 |
CL2017002959A1 (es) | 2018-05-11 |
CN107849824A (zh) | 2018-03-27 |
CA2986087A1 (en) | 2016-12-01 |
JP2018515696A (ja) | 2018-06-14 |
EP3298197A4 (en) | 2019-01-09 |
WO2016190801A1 (en) | 2016-12-01 |
BR112017024581A2 (pt) | 2018-07-31 |
US20180155875A1 (en) | 2018-06-07 |
EP3298197A1 (en) | 2018-03-28 |
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