U.S. patent application number 14/474510 was filed with the patent office on 2014-12-18 for method for the production of an elastic composite material with a textile surface.
This patent application is currently assigned to MONDI CONSUMER PACKAGING TECHNOLOGIES GMBH. The applicant listed for this patent is MONDI CONSUMER PACKAGING TECHNOLOGIES GMBH. Invention is credited to Dieter HOMOELLE, Marcus SCHOENBECK.
Application Number | 20140367032 14/474510 |
Document ID | / |
Family ID | 44010106 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140367032 |
Kind Code |
A1 |
HOMOELLE; Dieter ; et
al. |
December 18, 2014 |
METHOD FOR THE PRODUCTION OF AN ELASTIC COMPOSITE MATERIAL WITH A
TEXTILE SURFACE
Abstract
A method for the production of an elastic composite material
with a textile surface. First, a laminate is produced, which has
elastic cover layers and a core composed of a nonwoven fabric.
Subsequently, the laminate is separated into two strips, each of
which has a cover layer and an adhering layer of nonwoven fabric,
by tearing open the core.
Inventors: |
HOMOELLE; Dieter; (Ochtrup,
DE) ; SCHOENBECK; Marcus; (Versmold, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MONDI CONSUMER PACKAGING TECHNOLOGIES GMBH |
Gronau |
|
DE |
|
|
Assignee: |
MONDI CONSUMER PACKAGING
TECHNOLOGIES GMBH
Gronau
DE
|
Family ID: |
44010106 |
Appl. No.: |
14/474510 |
Filed: |
September 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13299547 |
Nov 18, 2011 |
8852392 |
|
|
14474510 |
|
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Current U.S.
Class: |
156/184 ;
156/248 |
Current CPC
Class: |
D04H 1/42 20130101; D04H
1/4291 20130101; B32B 5/022 20130101; Y10T 156/1184 20150115; B32B
38/10 20130101; B32B 38/0004 20130101; Y10T 156/1168 20150115; B32B
37/1284 20130101; Y10T 156/1189 20150115; B32B 2307/51 20130101;
B32B 2555/02 20130101; B32B 2305/20 20130101 |
Class at
Publication: |
156/184 ;
156/248 |
International
Class: |
B32B 38/10 20060101
B32B038/10; B32B 5/02 20060101 B32B005/02; B32B 38/00 20060101
B32B038/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2010 |
EP |
10 195 598.7 |
Claims
1. A method for the production of an elastic composite material
with a textile surface, comprising: producing a laminate that has
elastic cover layers formed of elastic film webs and a core
composed of nonwoven fabric, wherein the core of the laminate
comprises a slightly consolidated melt-blown fabric having a weight
per surface area unit of 5 g/m.sup.2 to 20 g/m.sup.2, and
subsequently separating the laminate into two strips by tearing
open the core, wherein a parting plane runs through the core and
the two strips resulting from tearing open the core each have a
cover layer and an adhering layer of nonwoven fabric with constant
values with regard to material thickness and the weight per surface
area unit, within close tolerance limits.
2. The method according to claim 1, wherein the nonwoven fabric of
the laminate comprises polyolefin fibers.
3. The method according to claim 1, wherein the elastic cover
layers of the laminate have a layer thickness between 20 .mu.m and
100 .mu.m and comprise a styrene block copolymer or a thermoplastic
polyolefin elastomer.
4. The method according to claim 1, wherein the nonwoven fabric and
the elastic cover layers are glued together.
5. The method according to claim 1, wherein the step of separating
comprises grasping the strips separately and pulling them apart by
applying tensile forces.
6. The method according to claim 1, wherein the strips are passed
over driven rollers and wound up separately.
7. The method according to claim 1, wherein the step of tearing
open the core is supported by a blade disposed in a parting plane.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and Applicant claims
priority under 35 U.S.C. .sctn.120 of U.S. application Ser. No.
13/299,547 filed on Nov. 18, 2011, which claims priority under 35
U.S.C. .sctn.119 from European Patent Application No. 10 195 598.7
filed on Dec. 17, 2010, the disclosures of each of which are hereby
incorporated by reference. A certified copy of priority German
Patent Application No. 10 195 598.7 is contained in parent U.S.
patent application Ser. No. 13/299,547.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a method for the production of an
elastic composite material with a textile surface.
[0004] 2. The Prior Art
[0005] Elastic composite materials with a textile surface are used,
among other things, for the production of baby diapers, for example
as tapes or as an elastic back-sheet, incontinence articles,
feminine hygiene products, and the like. In these applications, the
textile surface, which must be produced in cost-advantageous
manner, has great importance. In this connection, the textile
surface is not allowed to impair the elasticity of the film.
[0006] Composite materials composed of an elastic carrier film and
a nonwoven fabric that is laminated on are known. The fabric forms
a solid structure that decisively influences the stretching
behavior of the composite material. Composite materials composed of
an elastic carrier film and a nonwoven fabric that is laminated on
must therefore be mechanically activated, by mechanical stretching,
after the lamination process.
[0007] A method for the production of an elastic composite material
with a textile surface is described in European Patent Application
No. EP 2 177 654 A1, in which a layer of melt-blown nonwoven is
produced and glued onto an elastic film without any prior
consolidation. In this method, the nonwoven layer is not rolled up
and unrolled, and no guidance of the nonwoven layer under tensile
stress is provided. The nonwoven layer can therefore be formed with
little strength and, in particular, with a low weight per surface
area unit, and does not greatly hinder elastic stretching of the
composite material. For this reason, the composite material does
not require any subsequent mechanical activation. However, the bond
strength between the fibers of the textile layer and the elastic
film is not yet satisfactory. Since the work is conducted with
loose fibers, to a great extent, it is not ensured that all the
fibers will be sufficiently anchored in the adhesive matrix. Fibers
can unintentionally come loose from the composite and be taken in
by the user.
SUMMARY OF THE INVENTION
[0008] It is therefore an object of the invention to provide a
method for the production of a composite material with a textile
surface, which material has great stretching capacity, and the
textile surface of which material does not contain any loose fibers
that come loose from the composite during use of the composite
material.
[0009] This object is accomplished according to the invention by a
method for the production of an elastic composite material, in
which first a laminate is produced, which has elastic cover layers
and a core composed of a nonwoven fabric. The laminate is
subsequently separated into two strips, each of which has a cover
layer and an adhering layer of nonwoven fabric, by tearing open the
core. The method has the advantage that the fibers of the textile
surface are bound in the nonwoven fabric, and that when the core,
which consists of a nonwoven fabric, is torn open, no free fibers
that can easily come loose from the composite are formed. A
nonwoven fabric that is slightly consolidated can be used. The
degree of consolidation can be adjusted, for example when using
calender consolidation, so that the composite material can be
elastically stretched without subsequent mechanical activation, and
so that the stretching properties are determined by the elasticity
of the cover layer.
[0010] In order to separate the laminate, the strips are preferably
grasped separately and pulled apart by applying tensile forces. The
strips can be guided over driven rollers and wound up separately.
The separation process is connected with mechanical activation of
the elastic cover layer of the strips, specifically by means of
stretching of the elastic cover layers during the pulling-off
process. During pulling off and winding up of the strips, the
strips can be stretched in the transverse direction and/or the
longitudinal direction, by means of with suitable devices. In
particular, the strips can also be passed over profiled rollers in
which over-stretching of the strips transverse to the take-off
direction takes place. In this way, the stretching properties of
the composite material can be influenced and further improved.
[0011] Tearing open the nonwoven fabric can be supported by means
of a blade disposed in the separation plane.
[0012] The laminate with elastic cover layers and a core composed
of nonwoven fabric can be produced in different ways. Preferably,
the nonwoven fabric is laminated in between two elastic film webs.
However, extrusion lamination, in which the elastic layers are
applied to the nonwoven fabric by means of extrusion, is
fundamentally also possible.
[0013] The elastic cover layers preferably have a layer thickness
between 20 .mu.m and 100 .mu.m, and can consist of a styrene block
copolymer or a thermoplastic polyolefin elastomer. In addition to
mono-films, multi-layer co-extruded films can also be used for the
cover layers. In particular, perforated or breathable elastic films
can also be used for the cover layers. When using a breathable
elastic film, this important property is maintained in the
composite material. In place of an elastic film, an elastic
nonwoven fabric that has sufficient tensile strength can also be
used.
[0014] The nonwoven fabric and the elastic film webs or elastic
cover layers are preferably glued to one another, whereby
polyurethane adhesive and hot-melt adhesives are particularly
suitable. The adhesive can be applied over the entire area or in
patterns, for example in dots. Full-area application of adhesive is
preferred, whereby an adhesive application with an application
amount between 1 g/m.sup.2 and 2.5 g/m.sup.2 is sufficient when
using a solvent-free one-component polyurethane adhesive (1-K-PUR).
When using a hot-melt adhesive, a higher application weight of 3
g/m.sup.2 to 5 g/m.sup.2 will generally be necessary.
[0015] The nonwoven fabric that forms the core of the laminate and
is torn open in the course of the production process preferably
consists of a melt-blown nonwoven. The fibers of a melt-blown
nonwoven are produced by extrusion, and usually exit from multiple
holes of an extrusion nozzle disposed next to one another.
Immediately after leaving the extrusion nozzle, the viscous polymer
strands that exit from the holes are impacted with compressed air
and stretched. Melt-blown fibers are very thin and guarantee good
homogeneous coverage of the elastic cover layers even at a low
weight per surface area unit, and distinguish themselves by their
particularly soft appearance. The nonwoven preferably consists of
polyolefin fibers, particularly polypropylene fibers. The
melt-blown nonwoven is only slightly consolidated for the method
according to the invention, and can be used at a weight per surface
area unit of 5 g/m.sup.2 to 20 g/m.sup.2. The degree of
consolidation, for example by means of calender consolidation, is
guided by the desired stretching properties of the composite
material.
[0016] A multi-layer nonwoven fabric with an SMS layer structure
(spun-melt-spun) can also be used as a nonwoven fabric; this has
outer layers composed of a spun-bonded nonwoven fabric (S) and a
center nonwoven layer composed of melt-blown fibers (M). The
combination of layers composed of a spun-bonded nonwoven fabric and
a melt-blown nonwoven imparts greater strength in the machine
direction (MD direction) to the nonwoven fabric. When the
pre-finished laminate is torn open, separation of the nonwoven
fabric within the core layer, which consists of a melt-blown
nonwoven, takes place. It was found that the material thickness and
the weight per surface area unit of the strips separated by tearing
open the laminate remains constant, within close tolerances, if the
parting plane runs through a core layer composed of a melt-blown
nonwoven. High-quality composite material strips are obtained,
particularly strips with a very high-quality textile surface.
[0017] Other nonwoven fabrics can also be used for the method
according to the invention. However, the quality of the textile
surface is poorer, for example if a carded nonwoven is used as the
core layer of the laminate.
[0018] A composite material produced according to the method
according to the invention is suitable for hygiene articles, for
example for sections or closure elements on baby diapers and
incontinence articles. Furthermore, so-called soft-touch films for
applications outside of the hygiene sector can also be produced
according to the method according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Other objects and features of the present invention will
become apparent from the following detailed description considered
in connection with the accompanying drawings. It is to be
understood, however, that the drawings are designed as an
illustration only and not as a definition of the limits of the
invention.
[0020] In the drawings, wherein similar reference characters denote
similar elements throughout the several views:
[0021] FIG. 1 shows a method for the production of an elastic
composite material with a textile surface,
[0022] FIG. 2 shows a section through a laminate that is produced
as a pre-product, in the method shown in FIG. 1, and
[0023] FIG. 3 shows the separation of the pre-product shown in FIG.
2, in a representation that is enlarged as compared with FIG.
1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] Referring now in detail to the drawings, the method shown in
FIG. 1 serves for the production of an elastic composite material
with a textile surface, which can be used, for example, as a
soft-touch film or as an elastic element on baby diapers,
incontinence articles, and the like. In the method, in a first
step, a laminate 1 is produced as a pre-product; this laminate has
elastic cover layers 2, 2' and a core 3 composed of a nonwoven
fabric. FIG. 2 shows the layer structure of the pre-product.
Subsequently, laminate 1 is separated into two strips 4, 4' by
tearing open core 3; these strips each have a cover layer 2, 2' and
an adhering layer composed of nonwoven fabric 5. Strips 4, 4' each
form a method product that can be used as an elastic composite
material, without any subsequent mechanical activation.
[0025] Core 3 consists of a melt-blown nonwoven or has a
multi-layer structure with outer layers composed of a spun-bonded
nonwoven fabric and a center nonwoven layer composed of melt-blown
fibers. A nonwoven fabric web 6 that forms core 3 is laminated in
between two elastic film webs 7, and glued to film webs 7. Adhesive
8 is preferably applied, over the full area, to the surface of film
web 7 that lies adjacent to the nonwoven fabric. Polyurethane
adhesives or hot-melt adhesives can be used as adhesive 8.
[0026] Laminate 1 is separated by tearing open core 3 to form two
strips 4, 4'. Strips 4, 4' are grasped separately and pulled apart
by applying tensile forces. According to the representation in FIG.
1, strips 4, 4' are passed over driven rollers of a take-off device
9 and wound up separately. Optionally, take-off device 9 can be
combined with a stretching device in which strips 4, 4' are
stretched in the transverse direction and thereby mechanically
activated.
[0027] Tearing open core 3 can be supported by means of a blade 10
disposed in the parting plane.
[0028] When comparing FIGS. 2 and 3, it can be seen that elastic
composite materials, namely strips 4, 4', are produced according to
the method according to the invention; these strips have an elastic
carrier as well as a textile surface. The elastic carrier is formed
by a cover layer 2, 2' of laminate 1, and gives the composite
material its mechanical properties. The textile structure is
dependent on the nonwoven fabric used in core 3 of laminate 1.
Preferably, separation takes place through a nonwoven layer
composed of a melt-blown nonwoven, the fibers of which are thin and
form a high-quality textile surface during separation. A slightly
consolidated nonwoven is processed for the production of laminate 1
that forms the pre-product. No free fibers that can come loose when
the composite material is used are formed as the result of the
separation of the nonwoven layer in the subsequent step. When
nonwoven fabric core 3 is separated, strips 4, 4' are formed, which
have constant values with regard to the material thickness and
their weight per surface area unit, within close tolerance
limits.
[0029] Accordingly, while only a few embodiments of the present
invention have been shown and described, it is obvious that many
changes and modifications may be made thereunto without departing
from the spirit and scope of the invention.
* * * * *