U.S. patent application number 14/009173 was filed with the patent office on 2014-05-01 for spunlaced nonwovens as hook and loop fastener component.
This patent application is currently assigned to RKW SE. The applicant listed for this patent is Ludwig Bormann, Andreas Kirsch, Gunter Schreiner. Invention is credited to Ludwig Bormann, Andreas Kirsch, Gunter Schreiner.
Application Number | 20140115838 14/009173 |
Document ID | / |
Family ID | 44065410 |
Filed Date | 2014-05-01 |
United States Patent
Application |
20140115838 |
Kind Code |
A1 |
Kirsch; Andreas ; et
al. |
May 1, 2014 |
SPUNLACED NONWOVENS AS HOOK AND LOOP FASTENER COMPONENT
Abstract
The present invention relates to the use of a spunlaced nonwoven
fabric made of continuous filaments as loop material for hook and
loop fasteners. The invention also relates to a loop material made
of a nonwoven fabric and the production thereof.
Inventors: |
Kirsch; Andreas; (Bockenem,
DE) ; Bormann; Ludwig; (Babensham, DE) ;
Schreiner; Gunter; (Schnaitsee, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kirsch; Andreas
Bormann; Ludwig
Schreiner; Gunter |
Bockenem
Babensham
Schnaitsee |
|
DE
DE
DE |
|
|
Assignee: |
RKW SE
Frankenthal
DE
|
Family ID: |
44065410 |
Appl. No.: |
14/009173 |
Filed: |
March 29, 2012 |
PCT Filed: |
March 29, 2012 |
PCT NO: |
PCT/EP2012/001381 |
371 Date: |
December 16, 2013 |
Current U.S.
Class: |
24/451 ; 24/442;
28/104; 28/165 |
Current CPC
Class: |
D04H 3/11 20130101; D04H
1/498 20130101; D04H 3/16 20130101; A44B 18/0011 20130101; Y10T
24/2783 20150115; A61F 13/627 20130101; Y10T 24/27 20150115; A61F
13/51476 20130101 |
Class at
Publication: |
24/451 ; 28/104;
28/165; 24/442 |
International
Class: |
A44B 18/00 20060101
A44B018/00; D04H 3/16 20060101 D04H003/16; D04H 1/498 20060101
D04H001/498 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2011 |
EP |
11002732.3 |
Claims
1-15. (canceled)
16. Use of a spunlaced non-woven material of continuous filaments
as female component (loop component) of a hook-and-loop fastening
system, wherein no openings are introduced into the non-woven
material and the non-woven material does not encompass any bonding
prior to the spunlacing.
17. Use according to claim 16, wherein the continuous filaments of
the spunlaced non-woven material are bonded in defined areas,
wherein the bonding is 1-25%, preferably 2 to 20% of the total
surface.
18. Use according to claim 16, wherein the non-woven material is
connected to at least one further layer, preferably a film,
preferably by means of extrusion coating, adhesive lamination,
ultrasound welding or by means of thermal lamination.
19. Use according to claim 18, wherein the loops of the non-woven
material penetrate into the material of the further layer or an
adhesive, with which the non-woven material and the further layer
are connected, to 1 to 50% of the thickness of the non-woven
material.
20. Use according to claim 16, wherein the non-woven material is
applied to an absorbent article, in particular a diaper or pad, as
loop component for fastening the latter.
21. Use according to claim 18, wherein the non-woven material,
which is connected to the further layer forms the back sheet of a
sanitary product, in particular of a diaper.
Description
[0001] The present invention relates to the use of spunlaced
non-woven materials of continuous filaments as loop component of
hook-and-loop fasteners as well as loop components for
hook-and-loop fasteners of spunlaced non-woven materials of
continuous filaments.
[0002] For diapers different alternatives of closing systems are
used today, wherein the closing of the diaper is carried out either
by means of an adhesive tape on a film or by means of a hook tape
onto a loop layer. Traditional hook/loop variants, generally
referred to as hook-and-loop fastener, are the closing systems with
higher quality, in the case of which the loop layer consists mainly
of textile materials. The customer perceives them as being of a
higher quality, because they are also known as closing systems for
clothing and shoes. In the case of cost-sensitive products for the
temporary or single use, cheaper hook-and-loop alternatives must be
used, which can be produced at lower cost structures. In the area
of absorbent disposables, in particular diapers, such hook-and-loop
fastening devices are described e.g. in WO 96/22065, EP 719 533, EP
721 770 and WO 95/25496.
[0003] The use of existing hook-and-loop fasteners on products for
temporary or single use is limited due to the costs of the
fasteners, relative to other fastening types. The demand for
cost-efficient solution alternatives is thus a high priority for
this product group, specifically for absorbent disposables, such as
diapers.
[0004] For this reason, attempts have already been made early on to
develop loop systems based on non-woven materials. The non-woven
materials produced by means of the initially typical processes, had
to be post-treated, so as to shape the fibers to form a
loop-forming fiber mat (e.g. subsequent special thermal
bonding).
[0005] Even though the outer layers of absorbent disposables, in
particular of diapers, are preferably produced with a surface, the
appearance and the feel of which are as similar as possible to a
textile fabric when being touched. For this purpose, a composite of
liquid-tight film and a non-woven is mostly foreseen as outer layer
as textile-like outer layer. In spite of the successes in this
regard, however, the current surfaces are for the most part not
sufficient to directly hook the male hook component of a
hook-and-loop-fastening device into this surface. The adhesive
forces attained hereby are too small.
[0006] A formation of the entire outer surface with the volume of
the non-woven, which is required for this purpose, is not prudent
for cost reasons, because this is only possible via non-wovens
comprising a higher thickness or higher grammage of the non-woven,
respectively. For example, a non-woven can provide for a sufficient
adhesion by means of a corresponding folding. For costs reasons,
however, steadily reduced material consumption is called for and
the increasingly reduced material thicknesses, approximately 15 to
30 g/m.sup.2 are currently typical, do not make it possible to
offer a surface, which is suitable as loop component, at reasonable
costs even with a prestretching by means of ring rolling. Compared
to correspondingly more voluminous non-wovens made of the prevalent
polyolefin materials, the currently typical polyester fabrics or
knitted fabrics as loop component, which are produced separately
and which are applied to the back sheet, are more cost-efficient in
spite of the considerably higher material price of the polyester
non-woven and the additionally necessary fastening step.
[0007] As solution, WO 98/11855 proposes a loop component, which is
embodied in one piece with the outer layer (back sheet) of a
disposable. For this purpose, the back sheet is to consist of each
one inner and one outer layer, which are connected to one another,
wherein the outer layer of non-woven is imperatively made to be
sufficiently voluminous by means of prestretching in the landing
zone area/loop area and is not connected to or less connected to
the inner layer in the area, which later forms the loop component
of the hook-and-loop fastening device. In the case of this method,
however, the area of the landing zone must be produced in
particular with the help of the prestretching for a sufficient
closing force, too.
[0008] EP 1 915 918 proposes a method for producing composites,
which are suitable as loop component of hook-and-loop fasteners, in
the case of which a film and a non-woven are brought together on a
heating cylinder, wherein the heating cylinder heats the film to
the molten state. Thereby, a composite of film and non-woven is
formed, which is allowed to shrink by 1 to 10% in machine
direction, so that the non-woven increases in height by the
reduction of its dimension in the surface. The composite is
subsequently cooled to a temperature of below the melting
temperature of the film in a cooled roll nip. Such composites are
suitable as back sheet and allow for the anchoring of hooks,
particularly hooks adapted in a specific manner, to the non-woven.
This method requires for the film to shrink in the heat and does
not allow for the non-woven on its own to be attached to an article
as loop component.
[0009] A spunlaced non-woven is described in US 2009/0068394 A1 as
loop component, which imperatively encompasses 3 to 80 openings per
m.sup.2, in which the fibers, which are hooked into one another,
are intact on the lateral walls of the openings. The non-woven only
allows for a small number of opening and closing cycles, because it
already encompasses relatively high fiber disintegration in
response to low opening cycles. It is also suitable to be used as
back sheet. With 33 g/m.sup.2, however, the grammages in the
examples are still relatively high and US 2009/006839 A1 thus
proposes the use of strips of the non-woven material, which are
fastened subsequently, as loop component. In addition, the
introduction of the openings is time-consuming.
[0010] Thus, the object remains to simplify the production of
hook-and-loop fasteners or to provide for it in a more
cost-efficient manner, respectively, in the case of absorbent
disposables.
[0011] Surprisingly, it was now found that spunlaced non-woven
materials of continuous filaments encompass the necessary loop-like
fibrous web, into which the hook component of hook-and-loop
fasteners can be hooked, even without a post-treatment or the
connection to a further material layer.
[0012] The present invention thus solves the above-mentioned
problems of the known materials with the use of a spunlaced
non-woven material of continuous filaments as loop component of
hook-and-loop fasteners. The object is further solved by a loop
component for hook-and-loop fasteners, which comprises a spunlaced
non-woven material of continuous filaments.
[0013] According to the invention, spunlaced continuous filament
non-wovens are used. Due to their production process, the spunlaced
non-woven materials of continuous filaments provide for a fibrous
web, which is embodied in a loop-like manner and which thus
provides sufficient possibility to the hooks for being
anchored.
[0014] Non-woven materials with a grammage of 10 g/m.sup.2 to 50
g/m.sup.2, preferably of 15 to 30 g/m.sup.2, are well suited. In
individual cases, the grammage can be up to 150 g/m.sup.2. The
fiber structure, that is, the openness of the non-woven material as
well as the intertwining degree of the individual fibers can be
influenced and controlled specifically by means of the process
parameters of the spunlacing, so as to design the loops, which are
generated by means of the water jets, to be larger or smaller,
tighter or looser. This takes place by varying the water pressure,
the water quantity and/or the number and arrangement of the water
jets. It is also possible to create a non-woven material comprising
a loop-in-loop structure, similar to a knitted material, by means
of water jets. Spunlaced non-woven materials of continuous
filaments can be obtained commercially from RKW SE under the name
HyJet.RTM., for example.
[0015] It is advantageous that spunlaced non-woven materials of
continuous filaments can be used as loop component without further
treatment according to the invention. In particular, it is not
necessary to introduce defined openings and preferably this also
does not take place. The irregularly distributed opening
structures, which are present in the structure of the non-woven
material, need to be differentiated from the openings introduced
according to the state of the art and are not considered to be
openings.
[0016] It is furthermore advantageous that a bond is also not
necessary, neither by introducing bonding points, nor by providing
bonded areas comprising non-bonded points/surfaces.
[0017] Depending on the type of the used hook variants, the degree
of freedom of the formed loops, however, can be influenced
additionally or can be defined in a specific manner, respectively,
in that the fibrous web is bonded at discrete locations by means of
thermal solidification and/or ultrasonic welding and/or adhesion. A
bonding of the fibers in an area of 1-25%, preferably 2 to 20% of
the entire area, is sufficient here. This bonding can take place
before or after the spunlacing. A thermal solidification, in
particular by means of a thermobonding calander, is preferred. The
degree of solidification can be adjusted specifically by means of
the parameters thereof. The bonding can thereby take place in a
punctiform manner with different geometries, such as circle, ring,
rhombus or in a line shape.
[0018] It has also been surprisingly found that a non-woven
material of continuous filaments which is only slightly
pre-consolidated, e.g. by bonding points, can be treated by water
jets so that the jets of water specifically release filaments from
the bonding. This, too, can provide non-wovens with the loops
necessary for the hooks. It is important that the water jets do not
tear the filaments when releasing them from the bonding.
Preferably, jets are targeted in an in-line process at an already
thermally bonded spunbond such that individual filaments are
released again from the thermal bonding and so as to provide loops
for the hooks. Thereby the degree of loop formation can be
optimally adapted to the respective hook regardless of the gravure
design. In order to release the filaments from the bonding, this
connection may not be too strong, however. One has, for example, in
the case of thermal bonding to select a combination of calender
pressure and temperature, which allows the water jets to remove
single filaments from the bonding points. The fibers must not be
torn but only released from the bonding, such that larger loops are
formed thereby, into which the hooks can penetrate easier and find
optimum grip.
[0019] The non-woven material as such can be placed against the
provided location, e.g. on the outer skin of the diaper, during the
production of diapers or other products, and thus provides the
target surface for the hook tapes, which is designated landing
zone. The placement is hereby carried out by means of a fastening,
preferably adhesion, to e.g. the outer diaper skin, whereby the
continuous filaments are fastened to the bottom side of the
non-woven on the outer skin. The degree of freedom of the
individual loops is limited by means of this adhesion and is
adapted to the requirements of the hook material.
[0020] An alternative embodiment is to connect the non-woven
material according to the invention to a further layer, preferably
a polymer film, so as to realize a prefabricated non-woven film
composite as back sheet or landing zone material, thereby.
Different processes are available for this: direct extrusion (e.g.
by means of vacuum or in the roll nip), nozzle coating, adhesive
lamination, all of which are useful.
[0021] By varying the process parameters, the penetration depth of
the loop material into the film surface can be controlled during
direct extrusion, so that the available loop size and length can be
modified specifically in accordance with the used hook materials.
On principle, all methods for applying polymers (or EVA, hotmelt,
etc.) are suitable to attain a defined integration of the loop
material, wherein the polymer application can take place across the
entire surface as well as in defined partial surfaces. The loop
size and length can also be controlled by means of an application
across a partial surface.
[0022] A composite of spunlaced non-woven materials of continuous
filaments with a film, which is produced by means of the thermal
laminating processes, which is known from WO 2006/024394, is
particularly preferred. The production of a cost-efficient landing
zone alternative in response to a simultaneous control of the loop
formation is possible in a particularly easy and reproducible
manner with this. According to the invention, the penetration depth
of the non-woven material loops into the film layer can be defined
exactly here and the loop geometry can thus be adapted to the
different hook geometries in an ideal manner. In contrast to EP 1
915 918, however, a shrinking of the composite is avoided according
to the invention; the non-woven material shall essentially not
change its surface area. A slight shrinkage of up to 1%, preferably
of up to 0.5%, e.g., however, does not interfere.
[0023] The penetration depth of the film material or adhesive,
respectively, into the non-woven material can be between 1 and 50%
of the non-woven material, preferably between 10 and 40%. Good
fastening characteristics of the loops are thereby attained,
without the non-woven material losing its textile-like, soft
surface. The penetration depth should be at least 1%, preferably at
least 2% of the thickness of the non-woven material, so that the
loops are not detached from the non-woven material too much when
the hook component is detached.
[0024] All spinnable polymers, such as e.g. polyester, PLA,
polyolefins, in particular polypropylene and polyethylene, for
example, are suitable as material for the production of the
continuous filaments for the non-woven materials. Generally, other
polymers, which allow a spinning into fibers, can also be used. In
a particularly preferred manner, the continuous filaments and thus
the non-woven material consists of polypropylene material and/or
polyethylene material or a biodegradable material. The material
thereby contains polypropylene and/or polyethylene or a
biodegradable material and the typical additives, such as
processing aids, e.g., as well as possible production-related
constituent.
[0025] The filaments should encompass a thickness of between 10 and
70 .mu.m, so as to ensure a textile character on the one hand and
so as to guarantee a sufficient filament stability on the other
hand.
[0026] The required values of the hook shear forces of >10
N/2.54 cm are achieved with the non-woven materials or composites,
respectively, according to the invention for typical hooks, e.g. by
Binder, Velcro, 3M. Typically, shear strengths of 10 to 100 N/2.54
cm, preferably of 20 to 80 N/2.54 cm, particularly preferred of 30
to 70 N/2.54 cm are reached. In response to the opening, a maximum
peel force of 30 N/2.54 cm is not exceeded. Preferably, the peel
force is in the range of 1 to 25 N/2.54 cm, preferably of 3 to 15
N/2.54 cm. Also upon repeated opening and closing, the fibers are
not pulled out of the non-woven material to such an extent that the
hook forces fall below the desired values or that the non-woven
material appears to be ruffled.
[0027] The invention is to be explained by means of the figures
below, however, without being limited to the specifically described
embodiments. Unless otherwise stated or unless there are compelling
facts that follow from the context, the percentages refer to the
weight, in case of doubt to the total weight of the mixture.
[0028] The invention also refers to all of the combinations of
preferred embodiments, unless they are mutually exclusive. The
designations "about" or "approx." in combination with a number mean
that values, which are at least 10% higher or lower, or values,
which are 5% higher or lower, and values, which are 1% higher or
lower in any event, are included.
[0029] FIG. 1 shows a non-woven material according to the
invention.
[0030] FIG. 2 shows a non-woven material according to the invention
comprising discrete bonding points.
[0031] FIG. 3 shows a composite of non-woven material and film.
[0032] FIG. 4 shows a further composite of non-woven material and
film.
[0033] FIG. 5 shows a diaper.
[0034] A section of a non-woven material according to the invention
is illustrated schematically in FIG. 1. The non-woven material 1
neither has bonding points nor openings or other inhomogeneities.
The structure attained by means of the spunlacing alone already
forms sufficiently voluminous loops, so that the typical hooks
attain the necessary adhesion. Such a non-woven material can be
laminated onto a diaper or another sanitary product or onto
disposable clothing as landing zone. By fastening the filaments to
the support, the loop structure is fastened and the detachment of
the continuous filaments is limited.
[0035] FIG. 2 shows an embodiment wherein the loop structure is
fastened specifically by means of discrete bonding of the fibers at
the bonding points B, which assume an area of 1-25% of the total
area. This bonding can take place thermally, by means of ultrasound
or chemically by means of adhesives. The form of the bonding points
B can be chosen in a manner, which is known per se; for example
circle, rhombus, square, etc., in each case filled or unfilled, or
in a line shape are suitable.
[0036] FIG. 3 shows an embodiment wherein the non-woven material 1
is laminated with a film 2. For the lamination e.g. the direct
extrusion process or also the thermal laminating process described
in WO 2006/024394, is suitable. The material of the film 2 thereby
penetrates into the non-woven material 1. Penetration depths of
1-50% of the non-woven material thickness thereby turned out to be
suitable.
[0037] In a fourth embodiment, which is shown in FIG. 4, film 2 and
non-woven material 1 are laminated by means of adhesive. In this
case, the connection can be made across the entire surface or also
only across the partial surface. The adhesive material can be
applied in a punctiform or line-shaped manner, for example.
[0038] FIG. 5 illustrates the set-up of a diaper. The outer skin of
the diaper is formed of a composite of non-woven material and film,
the back sheet 4. The loop component must at least be present in
the landing zone 5. In that location, a loop component according to
the invention of non-woven material 1 or of non-woven material 1
and of film 2 is applied, e.g. by means of adhesion, or the entire
back sheet is formed of a composite of non-woven material 1 and
film 2. A typical diaper furthermore has an elastic cuff 7 in the
waist as well as elastic leg gathers 8. The suction core 9 is
arranged between the back sheet 4 and a top sheet and typically
encompasses a mixture of absorbent fibers, such as cellulose
wadding and a super absorber. Super absorbers are polymers, which
can absorb several times their own weight in liquid.
EXAMPLES
[0039] Determination of the Shear Force
TABLE-US-00001 Means: loops-specimen 50 mm * 150 mm hook tape 25.4
mm * 20 mm metal plate 50 mm * 150 mm rolling device 2 kg + 5 kg
adhesive tape one-sided (25.4 mm) and two-sided (50 mm)
[0040] The loop specimen is adhered to the metal plate by means of
a double-sided adhesive tape and is rolled down 2 times by means of
the rolling device 2 kg without pressure. The hook tape is adhered
to the one-sided adhesive tape. This hook tape is fastened to the
loop specimen in the center of the narrow side, which is 50 mm
wide, and is loaded 4 times by means of the rolling device with 5
kg. The loop specimen is clamped into the pulling device on the
bottom and the shear force 180.degree. is determined in N in
response to a withdrawal speed of 300 mm/min.
[0041] Determination of the Peel Force
TABLE-US-00002 Means: loops-specimen 50 mm * 150 mm hook tape 25.4
mm * 20 mm weight 500 g for hanging adhesive tape one-sided 25.4 mm
wide 100 mm long clamp 2 pieces, 50 mm wide
[0042] The hook tape is fastened to the center of the one-sided
adhesive tape. The hook tape is fastened to the center of the
non-woven specimen and is pressed together for 3 seconds using 2
fingers. The hook specimen is then hung up vertically and the hook
tape is loaded for 5 seconds with 500 g (shear direction). The loop
specimen is clamped vertically on the bottom in the pulling device
and the hook tape end, which points downward, is clamped into the
pulling device on the top and the peel force is determined in N in
response to a withdrawal speed of 300 mm/min.
[0043] All of the shear and peel forces are determined according to
the invention in accordance with the above methods. The forces are
specified in N/2.54 cm (N/inch). A conversion into N/1 cm is not
possible; for other dimensions, determinations must be made on
specimens comprising these dimensions.
Example 1
[0044] A purely spunlaced non-woven material of continuous
filaments in a weight class of 35 g/m.sup.2 was used as loop
component of a hook/loop closing system for an adult incontinence
product. The non-woven, RKW HyJet.RTM. 35 g/m.sup.2 was thereby
used in the form of a belt across the entire width of the
incontinence product and the closure took place by means of a hook
by Binder, Mikroplast 65445-C. The shear forces determined for the
specimens are 65 N, the peel force values are 45 N.
Example 2
[0045] A 25 g/m.sup.2 spunlaced non-woven of continuous filaments,
RKW HyJet.RTM. 25 g/m.sup.2, comprising a polypropylene film with a
weight of 20 g/m.sup.2 was laminated as landing zone material for a
baby diaper, so that the total composite encompassed a weight of 45
g/m.sup.2. Sections of this laminate with a size of 15.times.4 cm
were applied to the stomach area (landing zone area) of the diaper.
The hook tapes, for example the hook variant by Binder, Mikroplast
25445, can then be anchored in this area of the diaper for the
purpose of closing the diaper. The shear forces determined for the
specimens are 45 N and the peel values are 7 N.
LIST OF REFERENCE NUMBERS
[0046] 1 non-woven material [0047] 2 film [0048] 3 adhesive [0049]
4 back sheet [0050] 5 landing zone [0051] 6 hook tape [0052] 7 cuff
[0053] 8 leg gathers [0054] 9 suction core [0055] B bonding
point
* * * * *