U.S. patent application number 12/522164 was filed with the patent office on 2010-06-10 for method for manufacturing reduced-weight paper, thin cardboard and cardboard, and compounds obtained therewith.
This patent application is currently assigned to Lecce Pen Company SPA. Invention is credited to Clemente Nicolucci.
Application Number | 20100139878 12/522164 |
Document ID | / |
Family ID | 39323758 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100139878 |
Kind Code |
A1 |
Nicolucci; Clemente |
June 10, 2010 |
Method for Manufacturing Reduced-Weight Paper, Thin Cardboard and
Cardboard, and Compounds Obtained Therewith
Abstract
The invention concerns a compound for manufacturing paper or
cardboard, comprising a mixture of cellulose fibres and
heat-expandable substances suited to generate closed microbubbles,
in water dispersion, and wherein the mixture also contains additive
substances like bonding agents, mineral fillers, coatin
starches.
Inventors: |
Nicolucci; Clemente;
(Mussolente, IT) |
Correspondence
Address: |
IP STRATEGIES
12 1/2 WALL STREET, SUITE E
ASHEVILLE
NC
28801
US
|
Assignee: |
Lecce Pen Company SPA
Settimo Torinese
IT
|
Family ID: |
39323758 |
Appl. No.: |
12/522164 |
Filed: |
January 4, 2008 |
PCT Filed: |
January 4, 2008 |
PCT NO: |
PCT/IB2008/000017 |
371 Date: |
February 10, 2010 |
Current U.S.
Class: |
162/164.1 |
Current CPC
Class: |
D21H 17/35 20130101;
D21H 17/57 20130101; D21H 21/54 20130101 |
Class at
Publication: |
162/164.1 |
International
Class: |
D21H 17/33 20060101
D21H017/33 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 5, 2007 |
IT |
VI2007A000005 |
Claims
1) Water dispersion for manufacturing paper or cardboard of reduced
specific weight comprising cellulose fibres, thermally expandable
thermoplastic microspheres in an amount of 4.1% to 20.1% by weight
and a cohesion agent.
2) Water dispersion according to claim 1) characterised in that the
cohesion agent is a cationic starch.
3) Water dispersion according to claim 2) characterised in that the
cationic starch is present in an amount of 1.5% by weight.
4) Water dispersion according to claim 1) characterised in that it
further comprises a bonding agent suitable for making paper
writable with water inks.
5) Water dispersion according to claim 4) characterised in that the
bonding agent is a diketenic synthetic bonding agent.
6) Water dispersion according to claim 1) characterised in that the
cellulose fibres are virgin cellulose fibres and/or recycled
cellulose fibres.
7) Water dispersion according to claim 1) characterised in that it
further comprises a mineral filler.
8) Paper or cardboard produced with a water dispersion according to
claim 1).
9) Method for manufacturing paper or cardboard of reduced specific
weight with the following steps: a) preparing a water dispersion of
a mixture of cellulose fibres and thermally expandable
thermoplastic microspheres in an amount of 4.1% to 20.1% by weight,
b) addition of a cohesion agent to the water dispersion, c) drying
of the water dispersion to form a a paper or cardboard panel at a
temperature above 110.degree. C.
10) Method according to claim 9) characterised in that between step
a) and step b) is added a bonding agent suitable for making paper
writable with water inks.
11) Method according to claim 9) characterised in that the bonding
agent is a diketenic synthetic bonding agent.
12) Method according to claim 9) characterised in that the cohesion
agent is a cationic starch.
13) Method according to claim 12) characterised in that the
cationic starch is present in an amount of 1.5%.
14) Method according to claim 9) characterised in that the
cellulose fibres are virgin cellulose fibres and/or recycled
cellulose fibres.
15) Method according to claim 9) characterised in that the water
dispersion of step a) further comprises a mineral filler.
16) Method according to claim 9) characterised in that the
temperature in step c) lies between 115.degree. C. and 125.degree.
C.
17) Use of the water dispersion of claim 1) for manufacturing
industrial or handmade paper.
18) Use of thermally expandable thermoplastic microspheres as
substitution for cellulose fibres and/or to reduce weight in paper
or cardboard.
Description
[0001] The present invention concerns a method for preparing
compounds for the manufacture of paper or cardboard or thin
cardboard both in paper machines on an industrial scale and
manually, according to traditional handicraft techniques.
[0002] The present invention also concerns the compounds obtained
with the above mentioned method.
[0003] As is known, the paper usually manufactured both in paper
machines and with handicraft techniques consists of fibrous,
generally vegetable raw materials, felted together and then
dried.
[0004] The material that is most commonly used for manufacturing
paper is constituted by cellulose fibres obtained from trees or
plants in general.
[0005] The surface of the raw paper is then covered using a range
of additives that form a coat.
[0006] The coating agents are generally starch, polyvinyl acetate
(PVA) and many other products suitable for making different types
of paper.
[0007] The paper obtained in this way, however, has some
drawbacks.
[0008] A drawback is due to the fact that normally the paper
produced, when it is bulky, is also rather heavy and difficult to
transport.
[0009] This is the cause of the excessive weight of books, for
example school books, which may damage in particular the backbone
when the books are transported in school bags that students carry
on their backs.
[0010] Similarly, also the documents kept in bags or folders are
rather heavy when they are bulky.
[0011] A further drawback is due to the fact that paper
manufacturing costs are a consequence of the high quantity of
cellulose fibres used and of felled trees.
[0012] The object of the present invention is to carry out a
compound for manufacturing paper and/or cardboard and/or thin
cardboard that, considering the same volume produced, greatly
reduces its weight and consequently makes it easier to transport
for the user.
[0013] A further object of the present invention is to carry out a
compound that solves the problem of the damage to the backbone due
to the excessive weight carried.
[0014] It is another, yet not the least object of the invention to
carry out a compound that, considering the same volume of paper
and/or cardboard and/or thin cardboard to be manufactured, allows a
reduced quantity of cellulose fibres to be used for making
paper.
[0015] The objects mentioned above are achieved by the present
invention concerning a compound for the manufacture of paper or
cardboard, whose main principles are in accordance with the
contents of the first claim, as well as a method for the production
of the above mentioned compound.
[0016] Advantageously, the compound carried out according to the
invention allows the apparent specific weight of copy or printing
paper to be reduced from 1.0 to at least 0.5.
[0017] Still advantageously, the compound carried out according to
the invention allows the paper to be recycled with no need for any
separation of the material from which it is made.
[0018] Still to advantage, the compound carried out according to
the invention allows paper and cardboard to be manufactured that
are more elastic and flexible than the paper and cardboard of known
type.
[0019] According to the present invention, the production of paper
and cardboard is achieved by using virgin cellulose fibres and/or
fibres recycled before or after use, even if with the addition of
suitable auxiliary substances like bonding agents, mineral fillers,
starches and coating agents, in combination with a water dispersion
of substances that expand when heated and generate closed
microbubbles.
[0020] The microbubbles that expand when heated, in order to
function as expanding agents for the paper panel in the most
suitable way, are added to the fibre suspension (that is, the paper
pulp) before the addition of the suitable cohesion agents.
[0021] Cationic starch in solution has resulted to be particularly
suitable and effective.
[0022] The cationic starch in solution has been normally employed
here before the formation of the fibre panel that takes place on
the paper wire.
[0023] The dispersion particles that expand when heated, firmly
anchored to the constituent parts of the paper panel, were left to
rise at the same time as the paper and/or cardboard sheet was
dried.
[0024] In order to ensure the best possible development of the
expanding function in paper, the temperature of the drying
cylinders (or of the drying plate, if the paper is handmade) must
exceed 110.degree. C. and at such temperatures the contact time of
the paper panel, in which also the cellulose bonds form, must be
sufficient to ensure the drying of the sheet with at least 88% of
dry material.
[0025] Some non-limiting examples of formulation of the compound
carried out according to the invention are illustrated here
below.
EXAMPLE N. 1
[0026] Here paper is manufactured using 4% of polymer in the form
of expandable thermoplastic microspheres encapsulating a gas,
produced by Akzo Nobel and marketed under the Expancel.RTM.
trademark.
[0027] In this case, 20 kg of a dispersion of Expancel.RTM. were
added to a water dispersion having a dry concentration usually
included between 0.4% and 7%, constituted by 100 kg of whitened
cellulose obtained from fir, by 280 kg of whitened cellulose
obtained from eucalyptus and by 50 kg of micronized calcium
carbonate.
[0028] 35 kg of a water dispersion of diketenic synthetic bonding
agent were added to this pulp.
[0029] This type of bonding agent makes paper suitable for writing
with water inks.
[0030] This pulp is always kept under slight agitation and then
mixed with 7.5 kg of cationic starch dry solution, with the purpose
of obtaining good retention and increasing the number of bonding
contacts between fibres, auxiliary substances and expandable
bubbles.
[0031] In order to increase the surface strength characteristics of
the paper panel, paper was impregnated in the size press of the
paper machine with a 3% dry solution of maize starch.
[0032] The manufacturing speed of the paper strip was 50 m/min.
[0033] The drying cylinders coinciding with the points of formation
of the cellulose bonds were adjusted at a temperature ranging
between 115.degree. C. and 125.degree. C.
[0034] It is estimated that a book printed with this paper, with
the same format, number of pages and thickness, will weigh 19% less
than books manufactured according to the state of the art.
[0035] The composition of the pulp is illustrated in Table 1, while
the characteristics of the paper produced are illustrated in Table
2.
EXAMPLE N. 2
[0036] Here paper is manufactured using 10% of Expancel.RTM..
[0037] In this case, 50 kg of a dispersion of Expancel.RTM. were
added to a water dispersion constituted by 90 kg of whitened
cellulose obtained from fir, by 270 kg of whitened cellulose
obtained from eucalyptus and by 40 kg of micronized calcium
carbonate.
[0038] After homogenizing, obtained by slight agitation of the
paper pulp, 35 kg of a water dispersion of diketenic synthetic
bonding agent were added, which makes paper suitable for writing
with water inks.
[0039] This pulp is always kept under slight agitation and then
mixed with 7.5 kg of cationic starch dry solution, with the purpose
of obtaining good retention and increasing the number of bonding
contacts between fibres, auxiliary substances and expandable
bubbles.
[0040] In the paper panel drying and rising stage, the drying
cylinders coinciding with the points of formation of the cellulose
bonds were adjusted at a temperature ranging between 115.degree. C.
and 125.degree. C.
[0041] In order to increase the surface strength characteristics of
the paper panel, paper was impregnated in the size press of the
paper machine with a 3.5% dry solution of maize starch.
[0042] The manufacturing speed of the paper strip was 50 m/min.
[0043] It is estimated that a book printed with this paper, with
the same format, number of pages and thickness, will weigh 35% less
than books manufactured according to the state of the art.
[0044] The composition of the pulp is illustrated in Table 1, while
the characteristics of the paper produced are illustrated in Table
2.
EXAMPLE N. 3
[0045] Here paper is manufactured using 20% of Expancel.RTM..
[0046] 100 kg of Expancel.RTM. dispersion consisting of particles
having a diameter of a few microns were used.
[0047] In this case, the dispersion of Expancel.RTM. was added to a
water dispersion constituted by 90 kg of whitened cellulose
obtained from fir, by 240 kg of whitened cellulose obtained from
eucalyptus and by 30 kg of micronized calcium carbonate.
[0048] 30 kg of a water dispersion of diketenic synthetic bonding
agent, which makes paper suitable for writing with water inks, were
added to the pulp.
[0049] This pulp was always kept under slight agitation and then
mixed with 7.5 kg of cationic starch dry solution, with the purpose
of obtaining good retention and increasing the number of bonding
contacts between fibres, auxiliary substances and expandable
bubbles, in particular during the paper panel drying and rising
stage.
[0050] The manufacturing speed of the paper strip was 50 m/min.
[0051] The drying cylinders coinciding with the points of formation
of the cellulose bonds were adjusted at a temperature ranging
between 115.degree. C. and 125.degree. C.
[0052] In order to increase the surface strength characteristics of
the paper panel, the paper was impregnated in the size press of the
paper machine with a 4% dry solution of maize starch.
[0053] It is estimated that a book printed with this paper, with
the same format, number of pages and thickness, will weigh 49% less
than books manufactured according to the state of the art.
[0054] The composition of the pulp is illustrated in Table 1, while
the characteristics of the paper produced are illustrated in Table
2.
TABLE-US-00001 TABLE 1 Composition of industrial paper pulps.
Weight Industrial percentage kg/% reference Example 1 Example 2
Example 3 Whitened fir 100 kg 100 kg 90 kg 90 kg cellulose % 20.3
20.3 18.3 18.1 Whitened eucalyptus 300 kg 280 kg 270 kg 240 kg
cellulose % 60.9 56.9 54.8 48.2 Calcium 50 kg 50 kg 40 kg 30 kg
carbonate % 10.1 10.1 8.1 6.0 Expancel 0 20 kg 50 kg 100 kg % 0 4.1
10.1 20.1 Bonding agent 35 kg 35 kg 35 kg 30 kg % 7.1 7.1 7.1 6.0
Cationic starch 7.5 7.5 7.5 7.5 % 1.5 1.5 1.5 1.5 Total parts kg
492.5 kg 492.5 Kg 492.5 kg 497.5 kg % 100.0 100.0 100.0 100.0
Concentration of the 2.5% 3.0% 3.5% 4.0% solution of anionic starch
in the size press
TABLE-US-00002 TABLE 2 Characteristics of industrial papers
Industrial Characteristics reference Example 1 Example 2 Example 3
Thickness-micron % 165 176 185 193 Grams per 150 130 110 90 square
metre Apparent 0.910 0.737 0.595 0.466 specific weight Gluing with
excellent excellent excellent excellent Pelikan 4001 Offset
excellent excellent good moderate printability Copybility good good
good good Backprint good excellent good good opacity Mechanical
excellent excellent good sufficient workability
EXAMPLE N. 4
[0055] In this case the pulp described in Example 1, with the
addition of all its constituent parts, was partially used to
produce handmade paper sheets.
[0056] The fibre suspension was brought to the usual use
concentrations, always kept under slight agitation, filtered on the
wire of the handmade paper panel according to the traditional
manufacturing techniques, pressed and detached from the forming
wire, and then transferred onto normal dry felts, and wet-pressed
following the usual techniques.
[0057] The fibre panel has then assumed such a consistency as to be
able to be easily separated from the absorbing agents.
[0058] According to the traditional paper manufacturing techniques,
the paper or cardboard panel is laid and let to dry in the air at
ambient temperature.
[0059] In this and in the following examples, in order to allow the
thermal expansion of the gases encapsulated in the Expancel.RTM.
microspheres and to obtain both the rising of the fibre panel and a
sufficient cohesion of the constituent parts of the paper panel and
of the relevant bonds, the handmade paper sheets, still quite humid
(40-70% of water) were transferred onto a drying plate with
temperature adjusted at 120.degree. C. and provided with a
counter-felt exerting a slight pressure.
[0060] In these conditions, handmade cellulose sheets were obtained
in a few seconds.
[0061] The characteristics of the paper produced are illustrated in
Table 3.
EXAMPLE N. 5
[0062] Also in this case, like in Example 4, the handmade paper
sheets, still very humid (40-70% of water), were transferred onto a
drying plate with temperature adjusted at 120.degree. C. and
provided with a counter-felt exerting a slight pressure.
[0063] Expanded handmade sheets were produced in this case with the
pulp sample of Example 2.
[0064] The characteristics of the paper produced are illustrated in
Table 3.
EXAMPLE N. 6
[0065] Also in this case, like in Examples 4 and 5, the handmade
paper sheets, still very humid (40-70% of water) were transferred
onto a drying plate with temperature adjusted at 120.degree. C. and
provided with a counter-felt exerting a slight pressure.
[0066] Expanded handmade sheets were produced in this case with the
pulp sample of Example 3.
[0067] The characteristics of the paper produced are illustrated in
Table 3.
TABLE-US-00003 TABLE 3 Composition of handmade paper pulps. Weight
Hand percentage making kg/% reference Example 4 Example 5 Example 6
Whitened fir 100 kg 100 kg 90 kg 90 kg cellulose 20.3% 20.3% 18.3%
18.1% Whitened 300 kg 280 kg 270 kg 240 kg eucalyptus cellulose
60.9% 56.9% 54.8% 48.2% Calcium 50 kg 50 kg 40 kg 30 kg carbonate
10.1% 10.1% 8.1% 6.0% Expancel 0 20 kg 50 kg 100 kg 0 4.1% 10.1%
20.1% Bonding agent 35 kg 35 kg 35 kg 30 kg 7.1% 7.1% 7.1% 6.0%
Cationic 7.5 Kg 7.5 Kg 7.5 Kg 7.5 Kg starch 1.5% 1.5% 1.5% 1.5%
Total parts 492.5 kg 492.5 kg 492.5 kg 497.5 kg 100.0% 100.0%
100.0% 100.0%
TABLE-US-00004 TABLE 4 Characteristics of handmade papers Hand
making Characteristics reference Example 4 Example 5 Example 6
Thickness-micron % 215 241 292 375 Grams per 150 144 138 122 square
metre Apparent 0.70 0.60 0.47 0.32 specific weight Gluing with good
good good good Pelikan 4001 Physical- moderate moderate moderate
moderate mechanical consistency
[0068] The paper obtained according to the examples described has a
natural, valuable aspect and is also pleasant to touch.
[0069] As an alternative to Expancel.RTM., it will be possible to
use other products to generate microbubbles, like Avancell.RTM.
(copolymers of acrylonitrile) and Micropearl.RTM. (copolymers of
divinylbenzene).
[0070] As colloidal agents it is possible to use cationic agents,
anionic agents, non-ionic agents alone or mixed with each other
and/or in a different time frequency with colloids and/or retaining
and/or fixing agents that at the same time considerably increase
the physical-mechanical characteristics of the finished paper panel
of papers and cardboards.
[0071] An example of a non-ionic agent is polyoxypropylene that,
thanks to its high specific weight, allows a considerable quantity
of product to be saved when combined with a cationic or anionic
agent.
* * * * *