U.S. patent application number 11/513024 was filed with the patent office on 2007-02-22 for multi-ply planar absorbent product and process for manufacturing such a product.
Invention is credited to Hein Ferdinand, Harald Harlacher, Joachim Leonhardt, Emmanuelle Morin, Gunther Zoller.
Application Number | 20070042209 11/513024 |
Document ID | / |
Family ID | 34957080 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070042209 |
Kind Code |
A1 |
Morin; Emmanuelle ; et
al. |
February 22, 2007 |
Multi-ply planar absorbent product and process for manufacturing
such a product
Abstract
Adhesive (a1, a2) as a pattern of deposits is applied on both
sides of a hydrophilic spunbond non-woven inner ply (B) of low
grammage and no or low adhesion ability. Together with this inner
ply (B) a three ply planar absorbent product is made with tissue
outer plies (A,C) by exerting pressure on the adhesive such that
the adhesive penetrates through the inner ply (B) for achieving ply
bonding between the inner ply (B) and the opposite outer ply (C).
The different adhesive patterns do not disturb each other because
they do not coincide.
Inventors: |
Morin; Emmanuelle; (Vanves,
FR) ; Ferdinand; Hein; (Mannheim, DE) ;
Zoller; Gunther; (Schriesheim, DE) ; Harlacher;
Harald; (Mannheim, DE) ; Leonhardt; Joachim;
(Mannheim, DE) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Family ID: |
34957080 |
Appl. No.: |
11/513024 |
Filed: |
August 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/EP04/02077 |
Mar 2, 2004 |
|
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11513024 |
Aug 31, 2006 |
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Current U.S.
Class: |
428/537.5 ;
156/291; 162/124; 162/125; 162/158 |
Current CPC
Class: |
B32B 2317/12 20130101;
B32B 2307/726 20130101; B32B 5/022 20130101; B32B 38/06 20130101;
B31F 1/07 20130101; B32B 29/02 20130101; B32B 3/28 20130101; B32B
7/14 20130101; B32B 2305/20 20130101; D21H 27/38 20130101; B32B
7/12 20130101; B32B 5/26 20130101; B31F 2201/0787 20130101; Y10T
428/31993 20150401; B32B 37/1292 20130101; D21H 27/40 20130101;
B32B 2432/00 20130101; D21H 27/32 20130101; B31F 2201/0761
20130101 |
Class at
Publication: |
428/537.5 ;
162/124; 162/125; 162/158; 156/291 |
International
Class: |
D21H 27/30 20070101
D21H027/30 |
Claims
1. Multi-ply planar absorbent product, which comprises at least a
first (A) and a second (C) outer tissue ply and at least one inner
non-woven ply (B) bonded together, with an adhesive, wherein the
inner ply (B) is a material of no or low adhesion ability; a first
adhesive is present on one side of the inner ply (B) in a first
pattern of discrete adhesive deposits (al); a second adhesive is
present on the other side of the inner ply in a second pattern of
discrete adhesive deposits (a2), wherein said second pattern at
least partly does not coincide with the first pattern; and each of
said first and second adhesive penetrates through the inner ply (B)
thereby bonding together the inner ply (B) and at least the outer
ply (A;C) on the side opposite to the side where the adhesive is
applied.
2. Multi-ply planar absorbent product according to claim 1, wherein
at least one of the plies is embossed either separately or in
unison.
3. Multi-ply planar absorbent product according to claim 1, wherein
both of the outer plies (A,C) are embossed.
4. Multi-ply planar absorbent product according to claim 3, wherein
the embossment is such that sandwiching the inner ply (B), the
outer plies (A,C) are in "foot-to-foot" contact, and the adhesive
is present at least in some of the "foot-to-foot" areas.
5. Multi-ply planar absorbent product according to claim 3, wherein
the embossment is such that sandwiching the inner ply (B), the
outer plies (A,C) are in "nested" contact, and the adhesive is
present in at least some of the "nested" areas.
6. Multi-ply planar absorbent product according to claim 1, wherein
the adhesive mechanically surrounds fibers of the inner ply (B)
according to an interlocking grip.
7. Multi-ply planar absorbent product according to claim 1, wherein
the material of the non-woven inner ply (B) is a hydrophilic
material.
8. Multi-ply planar absorbent product according to claim 7, wherein
the material is a hydrophilic spunbond of low grammage.
9. Multi-ply planar absorbent product according to claim 1, wherein
the tissue of the outer plies (A,C) is a through-air-dried (TAD)
paper of substantially 18 g/m.sup.2, and the material of the inner
ply (B) is a hydrophilic spunbond non-woven of low grammage of
substantially 9 gsm.
10. Process for manufacturing a multi-ply planar absorbent product,
which comprises at least a first and a second outer tissue ply and
at least one inner non-woven ply made of a material of low adhesion
ability bonded together with an adhesive, said process comprising
the steps of: applying adhesive on one side of the inner ply in a
first pattern of a discrete adhesive deposits; applying adhesive on
the other side of the inner ply in a second pattern of discrete
adhesive; deposits, wherein said second pattern at least partly
does not coincide with the first pattern; placing the first and
second tissue plies on those sides of the inner ply carrying the
first and second pattern of adhesive respectively; and pressing
together the plies at least in those areas carrying the discrete
adhesive deposits to cause them to penetrate through the inner ply,
thereby bonding together at least the inner ply and the ply lying
opposite to the application side of the respective adhesive
deposit.
Description
FIELD OF THE INVENTION
[0001] The invention relates to multi-ply planar absorbent products
and especially 3-plies products made of plies of tissue paper and
non-wovens.
BACKGROUND OF THE INVENTION
[0002] The term non-woven (ISO 9092, DIN EN 29092) is applied to a
wide range of products which, in terms of their properties, are
located between those of paper (cf. DIN 6730, May 1996) and
cardboard (DIN 6730) on the one hand, and textiles on the other
hand. As regards non-woven a large number of extremely varied
production processes are used, such as the air-laid and spun-laced
techniques as well as wet-laid techniques. The non-woven includes
mats, non-woven fabrics and finished products made thereof.
Non-wovens may also be called textile-like composite materials,
which represent flexible porous fabrics that are not produced by
the classic methods of weaving warp and weft or by looping. In
fact, non-wovens are produced by intertwining, cohesive or adhesive
bonding of fibres, or a combination thereof. The non-woven material
can be formed of natural fibres, such as cellulose or cotton
fibres, but can also consist of synthetic fibres, such as
Polyethylene (PE), polypropylene (PP), polyurethane (PU),
polyester, nylon or regenerated cellulose, or a mix of different
fibres. The fibres may, for example, be present in the form of
endless fibres of pre-fabricated fibres of a finite length, as
synthetic fibres produced in situ, or in the form of staple fibres.
The nonwovens according to the invention may thus consist of
mixtures of synthetic and cellulose fibrous material, e.g. natural
vegetable fibres (see ISO 9092, DIN EN 29092).
[0003] A tissue paper is defined as a soft absorbent paper having a
low basis weight. One generally selects a basis weight of 8 to 30
g/m.sup.2, especially 10 to 25 g/m.sup.2 per ply. The total basis
weight of multiple-ply tissue products is preferably equal to a
maximum of 65 g/m.sup.2, more preferably to a maximum of 50
g/m.sup.2. Its density is typically below 0.6 g/cm.sup.3,
preferably below 0.30 g/cm.sup.3 and more preferably between 0.08
and 0.20 g/cm.sup.3.
[0004] The production of tissue is distinguished from paper
production by the its extremely low basis weight and its much
higher tensile energy absorption index (see DIN EN 12625-4 and DIN
EN 12625-5). Paper and tissue paper also differ in general with
regard to the modulus of elasticity that characterizes the
stress-strain properties of these planar products as a material
parameter.
[0005] A tissue's high tensile energy absorption index results from
the outer or inner creping. The former is produced by compression
of the paper web adhering to a dry cylinder as a result of the
action of a crepe doctor or in the latter instance as a result of a
difference in speed between two wires ("fabrics"). This causes the
still moist, plastically deformable paper web to be internally
broken up by compression and shearing, thereby rendering it more
stretchable under load than an uncreped paper.
[0006] Moist tissue paper webs are usually dried by the so-called
Yankee drying, the through air drying (TAD) or the impulse drying
method.
[0007] The fibers contained in the tissue paper are mainly
cellulosic fibres, such as pulp fibers from chemical pulp (e.g.
Kraft sulfite and sulfate pulps), mechanical pulp (e.g. ground
wood), thermo mechanical pulp, chemo-mechanical pulp and/or
chemo-thermo mechanical pulp (CTMP). Pulps derived from both
deciduous (hardwood) and coniferous (softwood) can be used. The
fibers may also be or include recycled fibers, which may contain
any or all of the above categories. The fibers can be treated with
additives--such as fillers, softeners, such as quaternary ammonium
compounds and binders, such as conventional dry-strength agents or
wet-strength agents used to facilitate the original paper making or
to adjust the properties thereof. The tissue paper may also contain
other types of fibers, e.g. regenerated cellulosic fibres or
synthetic fibers enhancing, for instance, strength, absorption,
smoothness or softness of the paper.
[0008] Tissue paper may be converted to the final tissue product in
many ways, for example, by embossing or laminating it into a
multi-ply product, rolled or folded.
[0009] If tissue paper is to be made out of pulp, the process
essentially comprises [0010] a forming that includes the headbox
and the forming wire portion, [0011] b the drying portion (TAD
(through air drying)) or conventional drying on the yankee
cylinder) that also usually includes the crepe process essential
for tissues, [0012] c typically the monitoring and winding
area.
[0013] Paper can be formed by placing the fibers, in an oriented or
random manner, on one or between two continuously revolving wires
of a paper making machine while simultaneously removing the main
quantity of water of dilution until dry-solids contents of usually
between 12 and 35% are obtained.
[0014] Drying the formed primary fibrous web occurs in one or more
steps by mechanical and thermal means until a final dry-solids
content of usually about 93 to 97%. In the case of tissue making,
this stage is followed by the crepe process which crucially
influences the properties of the finished tissue product in
conventional processes. The conventional dry crepe process involves
creping on a usually 4.5 to 6 m diameter drying cylinder, the
so-called yankee cylinder, by means of a crepe doctor with the
aforementioned final dry-solids content of the raw tissue paper
(wet creping can be used if lower demands are made of the tissue
quality). The creped, finally dry raw tissue paper (raw tissue) is
then available for further processing into the paper product or
tissue paper product according to the invention.
[0015] Instead of the conventional tissue making process described
above, the use of a modified technique is possible in which an
improvement in specific volume is achieved by a special kind of
drying within process section b and in this way an improvement in
the bulk softness of the thus made tissue paper is achieved. This
process, which exists in a variety of subtypes, is termed the TAD
(through air drying) technique. It is characterized by the fact
that the "primary" fibrous web (like a non-woven) that leaves the
forming and sheet making stage is pre-dried to a dry-solids content
of about 80% before final contact drying on the yankee cylinder by
blowing hot air through the fibrous web. The fibrous web is
supported by an air-permeable wire or belt (or TAD-fabric) and
during its transport is guided over the surface of an air-permeable
rotating cylinder drum (TAD-cylinder). Structuring the supporting
wire or belt makes it possible to produce any pattern of compressed
zones broken up by deformation in the moist state, also named
moulding, resulting in increased mean specific volumes and
consequently leading to an increase in bulk softness without
decisively decreasing the strength of the fibrous web. Such a
pattern is fixed in the area of the TAD-cylinder. Thereafter the
pattern is further imprinted between the TAD-fabric and the
Yankee-cylinder.
[0016] Creping may be conducted also during transfer of the paper
sheet from the forming wire directly to the TAD-fabric or via a
transfer fabric. For this creping the formingfabric runs faster
than the following fabric receiving the sheet (rush transfer). For
example, when applying the TAD technique for the production of raw
tissue and the usual double-screen sheet formation in c-wrap
configuration, for example, the so-called inner sheet-forming
screen can thus be operated at a speed that is up to 40% faster
than that of the next fabric or that of the subsequent felt, the
initially formed and already pre-drained paper web being
transferred to the next TAD fabric. This causes the still moist and
as a result plastically deformable paper web to be internally
broken up by compression and shearing, thereby rendering it more
stretchable under load than a paper that has undergone neither
"internal" nor external creping. This transfer of still plastically
deformable paper web at a differential speed that simultaneously
takes effect may also be brought about in other embodiments between
a transfer fabric and the so-called TAD imprinting fabric or
between two transfer fabrics.
[0017] Another possible influence on the softness and strength of
the raw tissue lies in the production of a layering in which the
primary fibrous web to be formed is built up by a specially
constructed headbox in the form of physically different layers of
fibrous material, these layers being jointly supplied as a pulp
strand to the sheet making stage.
[0018] When processing the raw fibrous web or raw tissue paper into
the final product (third process section), the following procedural
steps are normally used individually or in combination: cutting to
size (longitudinally and/or cross cutting), producing a plurality
of plies, producing mechanical ply adhesion, volumetric and
structural embossing, ply adhesion, folding, imprinting,
perforating, application of lotions, smoothing, stacking, rolling
up.
[0019] To produce multi-ply tissue paper products, such as
handkerchiefs, toilet paper, towels or kitchen towels, an
intermediate step preferably occurs with so-called doubling in
which the raw tissue in the finished product's desired number of
plies is usually gathered on a common multiply master roll.
[0020] The processing step from the raw tissue that has already
been optionally wound up in several plies to the finished tissue
product occurs in processing machines which include operations such
as repeated smoothing of the tissue, edge embossing, to an extent
combined with full area and/or local application of adhesive to
produce ply adhesion of the individual plies (raw tissue) to be
combined together, as well as longitudinal cut, folding, cross cut,
placement and bringing together a plurality of individual tissues
and their packaging as well as bringing them together to form
larger surrounding packaging or bundles. The individual paper ply
webs can also be pre-embossed and then combined in a roll gap
according to the foot-to-foot or nested methods.
[0021] Hygiene or wiping products primarily include all kind of
dry-creped tissue paper, wet-creped paper and cellulose or pulp
wadding or all kinds of non-wovens, or combinations, laminates or
mixtures thereof. Typical properties of these hygiene and wiping
products include the ready ability to absorb tensile stress energy,
their drapability, good textile-like flexibility, properties which
are frequently referred to as bulk softness, a high surface
softness, and a high specific volume with a perceptible thickness.
As high a liquid absorbency as possible and, depending on the
application, a suitable wet and dry strength as well as an
appealable visual appearance of the outer product surface is
desired. These properties, among others, allow these hygiene and
wiping products to be used, for example, as cleaning wipes such as
paper or non-woven wipes, windscreen cleaning wipes, industrial
wipes, kitchen paper, or the like; as sanitary products such as for
example toilet paper, paper or non-woven handkerchiefs, household
towels, towels, and the like; as cosmetic wipes such as for example
facials and as serviettes or napkins, just to mention some of the
products that can be used. Furthermore, the hygiene and wiping
products can be dry, moist, wet or pre-treated in any manner. In
addition, the hygiene and wiping products may be folded,
interleaved or individually placed, stacked or rolled, connected or
not, in any suitable manner.
[0022] Due to the above description, the products can be used for
personal and household use as well as commercial and industrial
use. They are adapted to absorb fluids, for decorative purposes,
for packaging or even just as supporting material, as is common for
example in medical practices or in hospitals. In terms of their
wide variety, hygiene and wiping products are now considered to be
everyday products.
[0023] From WO 01/36188 A is known a multi-ply absorbent disposable
surgical textile, especially a multi-ply absorbent wipe, comprising
at least a first and a second outer non-woven ply, and at least one
inner film bonded together with adhesive means. The inner film is a
thermoplastic copolyester elastomer and a first pattern of discrete
adhesive deposits is present on one side of the inner film and a
second pattern of discrete adhesive deposits is present on the
other side of the inner film, wherein said second pattern at least
partly does not coincide with the first pattern. In this document
is well described a method of making such multi-ply absorbent
structure in which the patterns of discrete adhesive deposits are
applied on each side of the inner film, followed by placing the
outer plies on said inner film and pressing them.
[0024] From WO 96/24485 A1 multi-ply paper laminates are known
using controlled adhesive strike-through. A carrier sheet of
synthetic spunbond non-woven having suitable airflow
characteristics is covered on each side with the less open paper
without strike-through. The adhesive is applied in a pattern on one
side of the carrier sheet. This laminate is a especially suited for
paper products such as disposable table napkins.
[0025] U.S. Pat. No. 3,958,055 A1 teaches adhesive bonding of
isotropic fiber webs to form pattern bonded composites. The process
for manufacturing a non-woven fabric in a single path involves
printing the adhesive on one web of cellulosic tissue in a clearly
defined fine line pattern, laying the fiber web on the adhesive
bearing surface of the tissue web, disposing a second cellulosic
tissue web on the fiber web, and hot calendering the three layer
composite so as to force the adhesive through the fiber web into
the second tissue web while bonding the fibers of reinforcing web
in place.
[0026] From U.S. Pat. No. 3,650,882 A1 is known a multi-ply paper
towel comprising for example three tissue plies. The adhesive is
applied either to the inner surface of the outer plies or on both
sides of the inner ply in order to achieve ply-bonding between the
inner ply and each of the outer plies.
[0027] Furthermore, from EP 0679122 B1, EP 0564319 B1 and EP
1017563 B1 a laminated fibrous structure is known comprising at
least three tissue plies, wherein the adhesive is applied on each
inner surface of the outer plies in order to achieve ply-bonding
between each of the outer plies and the inner ply.
SUMMARY OF THE INVENTION
[0028] It is the technical problem of the invention to provide a
multi-ply planar absorbent product and especially a toilet paper or
household towel and the like with good ply-bonding especially when
an inner ply is used, which is made of a material of low-adhesion
ability. "Adhesion Ability" is the ability of a material to bind
with another one using a given adhesive and resulting in a ply
bonding of an acceptable level. A ply bonding of an acceptable
level for tissue products is in a range between 0.08 and 0.3 N/50
mm (measured on a dry material, on the machine direction/mean value
of the peaks above the total mean value).
[0029] This problem is solved by a multi-ply planar absorbent
product, which comprises at least a first and a second outer tissue
ply and at least one inner non-woven ply bonded together, with an
adhesive, wherein the inner ply is a material of no or low adhesion
ability. A first adhesive is present on one side of the inner ply
in a first pattern of discrete adhesive deposits and a second
adhesive is present on the other side of the inner ply in a second
pattern of discrete adhesive deposits, wherein said second pattern
at least partly does not coincide with the first pattern. Each of
the first and second adhesive penetrates through the inner ply
thereby bonding together the inner ply and at least the outer ply
on the side opposite to the side where the adhesive is applied.
[0030] Preferably at least one of the plies is embossed either
separately or in unison. Especially both of the outer plies are
embossed and the embossment can be such that sandwiching the inner
ply, the outer plies are in "foot-to-foot" contact wherein the
adhesive is present at least in some of the "foot-to-foot" areas.
If steel rolls are used for embossing in these "foot-two-foot"
areas, the necessary pressure is achieved and applied on the
adhesive.
[0031] According to a further improvement the embossment is such
that sandwiching the inner ply, the outer plies are in "nested"
contact wherein the adhesive is present in at least some of the
"nested" areas. Preferably the adhesive surrounds mechanically
fibers of the inner ply according to an interlocking grip. Together
therewith the material of the non-woven inner ply can be a
hydrophilic material. Especially the material is hydrophilic
spunbond of low grammage. Therewith the tissue of the outer plies
may be a through-air-dried (TAD) paper of about 18 g/m.sup.2 and
the material of the inner ply then might be a hydrophilic spunbond
non-woven of low grammage of about 9 gsm.
[0032] Furthermore, the problem is solved by a process for
manufacturing a multi-ply planar absorbent product, which comprises
at least a first and a second outer tissue ply and at least one
inner non-woven ply made of a material of low adhesion ability
bonded together, with an adhesive, said process comprising the
steps of applying adhesive on one side of the inner ply in a first
pattern of discrete adhesive deposits, applying adhesive on the
other side of the inner ply in a second pattern of discrete
adhesive deposits wherein said second pattern at least partly does
not coincide with the first pattern. Then the first and the second
tissue plies are placed on those sides of the inner ply carrying
the first second pattern of adhesive respectively. Afterwards the
plies are pressed together at least in those areas carrying the
discrete adhesive deposits to cause them to penetrate through the
inner ply thereby bonding together at least the inner ply and the
ply lying opposite to the application side of the respective
adhesive deposit.
[0033] By the invention a product is achieved in which in an easy
manner, an appropriate ply bonding can be achieved when the inner
ply is of no or low adhesion ability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The invention is described hereafter on the basis of the
following drawings illustrating some embodiments according to the
present invention.
[0035] FIG. 1 shows the principle of ply-bonding a three-ply
product.
[0036] FIG. 2a to FIG. 2d show the steps of manufacturing a
three-ply planar absorbent product.
[0037] FIG. 3 to FIG. 5 show in three steps how adhesive penetrates
through an inner ply in order to achieve ply-bonding on the other
side.
[0038] FIG. 6 to FIG. 8 show different modes of manufacturing a
three-ply product with different modes of applying.
DETAILED DESCRIPTION OF THE INVENTION
[0039] As an example a three-ply product is described. These are
the plies A, B and C. The plies A and C are named the outer plies
and the ply B the inner ply. As an example the outer plies are made
of a material being 18 g/m.sup.2 TAD (through air-dried) tissue
paper. The material of the inner ply B is for example spunbond
hydrophilic low grammage non-woven of 9 gsm. Such a non-woven has a
low adhesion ability especially when the fiberes are covered by a
surfactant. For instance as non-woven is used a 100% Polypropylene
based hydrophilic spunbond (supplied from Supplier Union, 9 gsm,
reference S0900PPW).
[0040] For example the non-woven is hydrophilic due to application
of a surfactant while producing it.
[0041] In the following description an embodiment is shown where an
adhesive is used for ply-bonding.
[0042] In FIG. 1 is illustrated the application of drops of
adhesive al on one side 1 of the inner ply B. On the other side 2
of the inner ply B also drops of adhesive a2 are applied. In this
way patterns of adhesive drops are applied to the inner ply B in
such a manner that the patterns do not coincide. By the adhesive
ply-bonding is achieved between the plies and especially between
ply A and B and ply C and B. By the adhesive a2 a ply-bonding is
achieved between ply B and ply A and by the adhesive al between the
ply B and the ply C. The reason is that the material of the inner
ply B is in this example spunbond hydrophilic non-woven of low
grammage having a low adhesion ability so that by the adhesive a2
no or poor ply-bonding can be achieved between the inner ply B and
the outer ply C. The non-woven used is (supplied from supplier
UNION, 9 gsm, refernce SO900PPW) a 100% Polypropylenne based
hydrophilic spunbond. In this case the non-woven is hydrophilic due
to the application of a surfactant while producing it.Under
adhesion ability is to be understood the ability of a material to
bind with another one using a given adhesive and resulting in a ply
bonding of an acceptable level. A ply bonding of an acceptable
level for tissue production is in a range between 0.08 and 0.3 N/50
mm (average of peaks on dry material in the machine
direction).Therefore, by pressure application the adhesive a2
penetrates the inner ply B and is interlocked between the fibers
and the adhesive extending to the side 1 of the inner ply B forms a
ply-bonding with the outer ply A having a high adhesion ability.
The same happens with the adhesive a1 in the opposite manner. The
adhesive used is "SWIFT L 998/4", a Polyvinylacohol and
Polyethyleneglycol based adhesion of a viscosity being 18000 mPa at
26.degree. C.
[0043] The manufacturing process as a principle is illustrated in
FIG. 2a to FIG. 2d. According to FIG. 2a in the before mentioned
manner the adhesive is applied on two sides of the inner ply B by
an application tool 3 and 4. The result is visible from FIG. 2b. In
this step the inner ply B is brought together with the plies A and
C. According to the illustration in FIG. 2c the three-ply
configuration, for instance as a continuous web is fed into the
operation area of a pressure-marrying tool 5 and 6. The pressure is
exerted according to the arrows 7 to locations where the adhesive
is present so that the pressure is exerted not only on the plies
but also on the adhesive. The result after exerted pressure is
illustrated in FIG. 2d, which shows the well known "foot-to-foot"
configuration, which could also be a so called and well known
"nested"-configuration.
[0044] By the pressure exerted on the adhesive the adhesive
penetrates through inner ply B in order to be fixed there so that
the adhesive penetrated through the inner ply B causes ply-bonding
with the adjacent outer ply being of tissue paper having a high
adhesion ability.
[0045] The adhesive used herein may be for instance BVOH adhesive
of high dry content (Atesin 1900, 16% for instance,
Henkel-Polyvinyl Acetate Dispersion). Another adhesive is Polyvinyl
alcohol and Plyethylenglycol based (SWIFT L998/4). It has a
viscosity of 18.000 mPas at 26.degree. C.
[0046] FIG. 3 shows the three-ply configuration with an adhesive
drop al applied to the one side one of the inner ply B. According
to FIG. 4 pressure is applied to the adhesive drop via the outer
tissue ply A. This causes the adhesive drop al to penetrate through
the inner ply B such that an adhesive head h is formed by an
interlocking grip within the fiber configuration of the inner ply B
fixing the adhesive mechanically within the inner ply B. Some
adhesive is pressed through the inner ply B to extend by a "tail" t
in the direction of the inner side of the outer ply C where it
sticks to the inner side of the outer ply C being of material
having a high adhesion ability.
[0047] The manufacturing principle is more detailed illustrated in
three embodiments shown in FIG. 6, FIG. 7 and FIG. 8. According to
FIG. 6 the inner ply B runs through application rollers 8 and 9 of
application tools 3 and 4 for applying the adhesive a1 and a2 from
opposite sides on the inner ply sheet B. Thereafter the such
prepared inner ply B is guided together with the outer plies A and
C through pressure-marrying rolls 5, 6. At the locations 10 and 11
between the rolls 5 and 12 and the rolls 6 and 13 the outer plies A
and C are embossed. In general marrying--and embossing rolls and
also applicator rolls are known in this technical field so that it
is not necessary here to describe these means more in detail.
Downstream the rolls 5 and 6 the final product B as a three-ply
planar absorbent product.
[0048] Embodiments different from the one illustrated in FIG. 6 an
illustrated in FIG. 7 and FIG. 8. There are provided in running
direction spaced application tools 3 and 4 for applying the
adhesive on the inner ply B. Downstream thereof the inner ply B is
combined with the outer plies A and C between the pressure-marrying
rolls 5 and 6. According to FIG. 8 in the embossing stations 10 and
11 the outer plies A and C are embossed and probably applied with
additional adhesive by the application rolls 14, 15.
* * * * *