U.S. patent application number 16/073906 was filed with the patent office on 2019-02-14 for non-stretch bonded strand and film elastics.
The applicant listed for this patent is Kimberly-Clark Worldwide, Inc.. Invention is credited to WanDuk Lee, Davis Dang H. Nhan, Peiguang Zhou.
Application Number | 20190047268 16/073906 |
Document ID | / |
Family ID | 59743178 |
Filed Date | 2019-02-14 |
United States Patent
Application |
20190047268 |
Kind Code |
A1 |
Nhan; Davis Dang H. ; et
al. |
February 14, 2019 |
NON-STRETCH BONDED STRAND AND FILM ELASTICS
Abstract
A laminate includes a core structure having a first surface and
a second surface, the core structure including an elastic core
layer and a plastic core layer, wherein the elastic core layer is
one of a film, a plurality of strands, and a plurality of strips,
and wherein the plastic core layer is one of a film layer, a
plurality of strands, and a plurality of strips, the plastic core
structure reinforcing the core layer in the machine direction, and
a nonwoven first facing layer affixed to the first surface.
Inventors: |
Nhan; Davis Dang H.;
(Menasha, WI) ; Lee; WanDuk; (Appleton, WI)
; Zhou; Peiguang; (Appleton, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kimberly-Clark Worldwide, Inc. |
Neenah |
WI |
US |
|
|
Family ID: |
59743178 |
Appl. No.: |
16/073906 |
Filed: |
February 29, 2016 |
PCT Filed: |
February 29, 2016 |
PCT NO: |
PCT/US2016/020017 |
371 Date: |
July 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 7/02 20130101; B32B
25/08 20130101; B32B 2307/51 20130101; B32B 2553/00 20130101; B32B
25/042 20130101; B32B 5/18 20130101; B32B 2571/00 20130101; B32B
3/18 20130101; B32B 7/04 20130101; B32B 2038/0028 20130101; B32B
2262/065 20130101; B32B 2262/067 20130101; B32B 7/12 20130101; B32B
2307/5825 20130101; B32B 27/12 20130101; B32B 2250/04 20130101;
B32B 2262/04 20130101; B32B 27/08 20130101; B32B 2262/0207
20130101; B32B 2307/718 20130101; B32B 25/10 20130101; B32B
2262/0253 20130101; B32B 2262/0215 20130101; B32B 2555/00 20130101;
B32B 27/06 20130101; B32B 2262/02 20130101; B32B 37/203 20130101;
B32B 3/266 20130101; B32B 5/26 20130101; B32B 27/32 20130101; B32B
2437/00 20130101; B32B 2262/0223 20130101; B32B 2307/728 20130101;
B32B 2432/00 20130101; B32B 2262/062 20130101; B32B 2307/724
20130101; B32B 38/0012 20130101; B32B 5/022 20130101; B32B 2307/50
20130101; B32B 2262/0276 20130101; B32B 2307/732 20130101; B32B
2535/00 20130101; B32B 2262/023 20130101; B32B 2307/7265 20130101;
B32B 2262/0292 20130101; B32B 2262/14 20130101; B32B 2555/02
20130101; B32B 2262/0261 20130101 |
International
Class: |
B32B 27/12 20060101
B32B027/12; B32B 7/12 20060101 B32B007/12; B32B 5/02 20060101
B32B005/02; B32B 37/20 20060101 B32B037/20; B32B 38/00 20060101
B32B038/00 |
Claims
1. A laminate comprising: a core structure having a first surface
and a second surface, the core structure comprising an elastic core
layer and a plastic core layer, wherein the elastic core layer is
one of a film, a plurality of strands, and a plurality of strips,
and wherein the plastic core layer is one of a film layer, a
plurality of strands, and a plurality of strips, the plastic core
layer reinforcing the core structure in the machine direction; and
a fractured nonwoven first facing layer affixed to the first
surface.
2. The laminate of claim 1, wherein the plurality of strands is
disposed between the film layer and the first facing layer.
3. The laminate of claim 1, wherein the first facing layer is
affixed to the first surface with adhesive.
4. The laminate of claim 1, further comprising a nonwoven second
facing layer affixed to the second surface.
5. The laminate of claim 1, wherein the nonwoven first facing layer
is cellulose-based.
6. The laminate of claim 1, wherein the nonwoven first facing layer
is polymer-based.
7. The laminate of claim 1, wherein the nonwoven first layer
includes polymer and cellulose.
8. The laminate of claim 1, wherein the plastic core layer is a
film, and wherein the elastic core layer is a plurality of strands
or a plurality of strips.
9. The laminate of claim 1, wherein the elastic core layer is a
film, and wherein the plastic core layer is a plurality of strands
or a plurality of strips.
10. A method for producing a composite nonwoven elastic web
comprising an elastic web joined to a fibrous nonwoven web, the
method comprising: providing an elastic web comprising a core
structure having an elastic core layer and a plastic core layer,
wherein the elastic web has a first surface and a second surface;
stretching the elastic web to less than 100 percent stretch;
affixing a fibrous nonwoven web to the first surface of the
stretched elastic web to form a composite nonwoven elastic web;
relaxing the composite nonwoven elastic web; and activating the
nonwoven elastic web after affixing the fibrous nonwoven web,
thereby fracturing the fibrous nonwoven web.
11. The method of claim 10, wherein activating includes using a
groove rolling process or an intermeshing gears process.
12. The method of claim 10, wherein the elastic core layer is one
of a film, a plurality of strands, and a plurality of strips,
wherein the plastic core layer is one of a film layer, a plurality
of strands, and a plurality of strips.
13. The method of claim 12, wherein the elastic core layer is a
film, and wherein the plastic core layer is a plurality of strands
or a plurality of strips.
14. The method of claim 12, wherein the plastic core layer is a
film, and wherein the elastic core layer is a plurality of strands
or a plurality of strips.
15. The method of claim 10, wherein the fibrous nonwoven web is
affixed to the elastic web with a thermal, adhesive, ultrasonic, or
co-extrusion lamination method.
16. The method of claim 10, further comprising affixing a second
fibrous nonwoven web to the second surface.
17. The method of claim 10, wherein the fibrous nonwoven web is
cellulose-based.
18. The method of claim 10, wherein the fibrous nonwoven web is
polymer-based.
19. The method of claim 10, wherein the fibrous nonwoven web
includes polymer and cellulose.
20. A method for producing a composite nonwoven elastic web
comprising an elastic web joined to a fibrous nonwoven web, the
method comprising: providing an elastic web comprising a core
structure having an elastic core layer and a plastic core layer,
wherein the elastic web has a first surface and a second surface,
wherein the elastic core layer is a film, and wherein the plastic
core layer is a plurality of strands or a plurality of strips;
stretching the elastic web to less than 100 percent stretch;
affixing a fibrous nonwoven web to the first surface of the
stretched elastic web to form a composite nonwoven elastic web, the
fibrous nonwoven web including polymeric and/or cellulosic fibers;
relaxing the composite nonwoven elastic web; and activating the
nonwoven elastic web using a groove rolling process or an
intermeshing gears process after affixing the fibrous nonwoven web,
thereby fracturing the fibrous nonwoven web.
Description
BACKGROUND
[0001] The present disclosure is generally directed to processes
for forming composite nonwoven elastic webs and the composite
nonwoven elastic webs formed by such processes. In particular, the
present disclosure encompasses a composite nonwoven elastic web
that includes an elastic web joined to a nonwoven web and processes
for forming such composite nonwoven elastic webs. In particular,
the present disclosure is directed to elastic laminates and their
uses in various product applications.
[0002] Current elastic materials used in products in the global
market are generally based on stretch-bonded elastic laminate
technology with a nonwoven facing. In the stretch-bonded elastic
laminate process, elastic materials (film or strands) are stretched
to 3-5 times their relaxed length before being bonded to facing
materials. Cost analyses of current elastic laminates indicate that
the facing materials, such as spunbond (SB) and
spunbond-meltblown-spunbond (SMS) nonwovens account for more than
50% of the total elastic laminate cost because of the high usage of
facing materials.
SUMMARY
[0003] The composites described herein represent a new class of
soft, flexible, and cloth-like nonwoven/film structures that can
potentially be used for a variety of applications such as
functional elastics, cleaning wipes, medical fabrics, protection
garments, filtration, packaging, personal care articles, and
others.
[0004] In one aspect, a laminate includes a core structure having a
first surface and a second surface, the core structure including an
elastic core layer and a plastic core layer, wherein the elastic
core layer is one of a film, a plurality of strands, and a
plurality of strips, and wherein the plastic core layer is one of a
film layer, a plurality of strands, and a plurality of strips, the
plastic core layer reinforcing the core structure in the machine
direction, and a nonwoven first facing layer affixed to the first
surface.
[0005] In an alternate aspect, a method for producing a composite
nonwoven elastic web includes an elastic web joined to a fibrous
nonwoven web, the method including providing an elastic web
including a core structure having an elastic core layer and a
plastic core layer, wherein the elastic web has a first surface and
a second surface; stretching the elastic web to less than 100
percent stretch; and affixing a fibrous nonwoven web to the first
surface of the stretched elastic web to form a composite nonwoven
elastic web. The method also includes relaxing the composite
nonwoven elastic web and activating the nonwoven elastic web.
[0006] In another aspect, a method for producing a composite
nonwoven elastic web includes an elastic web joined to a fibrous
nonwoven web, the method including providing an elastic web
including a core structure having an elastic core layer and a
plastic core layer, wherein the elastic web has a first surface and
a second surface, wherein the elastic core layer is a film, and
wherein the plastic core layer is a plurality of strands or a
plurality of strips; and stretching the elastic web to less than
100 percent stretch. The method also includes affixing a fibrous
nonwoven web to the first surface of the stretched elastic web to
form a composite nonwoven elastic web, the fibrous nonwoven web
including polymeric and/or cellulosic fibers; relaxing the
composite nonwoven elastic web; and activating the nonwoven elastic
web using a groove rolling process or an intermeshing gears
process.
[0007] Objects and advantages of the disclosure are set forth below
in the following description, or can be learned through practice of
the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present disclosure will be more fully understood, and
further features will become apparent, when reference is made to
the following detailed description and the accompanying drawings.
The drawings are merely representative and are not intended to
limit the scope of the claims.
[0009] FIG. 1 illustrates an exploded schematic view of an elastic
laminate having an elastic layer and a plastic layer in accordance
with the present disclosure;
[0010] FIG. 2 illustrates an exploded schematic view of an elastic
laminate similar to that of FIG. 1, having a plastic layer and an
elastic layer in accordance with the present disclosure; and
[0011] FIG. 3 is a graphical illustration of elastic properties
with respect to a training pant "fit box" and in comparison to
prior elastic materials.
[0012] Repeat use of reference characters in the present
specification and drawings is intended to represent the same or
analogous features or elements of the present disclosure. The
drawings are representational and are not necessarily drawn to
scale. Certain proportions thereof might be exaggerated, while
others might be minimized.
DETAILED DESCRIPTION
[0013] As used herein the term "nonwoven fabric or web" refers to a
web having a structure of individual polymeric and/or cellulosic
fibers or threads that are interlaid, but not in an identifiable
manner as in a knitted fabric. Nonwoven fabrics or webs have been
formed from many processes such as for example, meltblowing
processes, spunbonding processes, bonded carded web processes,
those used to make tissue and towels, etc.
[0014] As used herein, the term "meltblown web" generally refers to
a nonwoven web that is formed by a process in which a molten
thermoplastic material is extruded through a plurality of fine,
usually circular, die capillaries as molten fibers into converging
high velocity gas (e.g. air) streams that attenuate the fibers of
molten thermoplastic material to reduce their diameter, which can
be to microfiber diameter. Thereafter, the meltblown fibers are
carried by the high velocity gas stream and are deposited on a
collecting surface to form a web of randomly dispersed meltblown
fibers. Such a process is disclosed, for example, in U.S. Pat. No.
3,849,241 to Butin, et al., which is incorporated herein in its
entirety by reference thereto. Generally speaking, meltblown fibers
can be microfibers that are substantially continuous or
discontinuous, generally smaller than 10 microns in diameter, and
generally tacky when deposited onto a collecting surface.
[0015] As used herein, the term "spunbond web" generally refers to
a web containing small diameter substantially continuous fibers.
The fibers are formed by extruding a molten thermoplastic material
from a plurality of fine, usually circular, capillaries of a
spinnerette with the diameter of the extruded fibers then being
rapidly reduced as by, for example, eductive drawing and/or other
well-known spunbonding mechanisms. The production of spunbond webs
is described and illustrated, for example, in U.S. Pat. No.
3,692,618 to Dorschner, et al., U.S. Pat. No. 3,802,817 to Matsuki,
et al., U.S. Pat. No. 3,338,992 to Kinney, U.S. Pat. No. 3,341,394
to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat. No.
3,502,538 to Levy, U.S. Pat. No. 3,542,615 to Dobo, et al., U.S.
Pat. No. 4,340,563 to Appel, et al. and U.S. Pat. No. 5,382,400 to
Pike, et al., which are incorporated herein in their entirety by
reference hereto thereto. Spunbond fibers are generally not tacky
when they are deposited onto a collecting surface. Spunbond fibers
can sometimes have diameters less than about 40 microns, and are
often between about 5 to about 20 microns.
[0016] As used herein the term "staple fiber" means fibers that
have a fiber length generally in the range of about 0.5 to about
150 millimeters. Staple fibers can be cellulosic fibers or
non-cellulosic fibers. Some examples of suitable non-cellulosic
fibers that can be used include, but are not limited to,
hydrophilically-treated polyolefin fibers, polyester fibers, nylon
fibers, polyvinyl acetate fibers, and mixtures thereof. Hydrophilic
treatments can include durable surface treatments and treatments in
polymer resins/blends. Cellulosic staple fibers include for
example, pulp, thermomechanical pulp, synthetic cellulosic fibers,
modified cellulosic fibers, and the like. Cellulosic fibers can be
obtained from secondary or recycled sources. Some examples of
suitable cellulosic fiber sources include virgin wood fibers, such
as thermomechanical, bleached and unbleached softwood and hardwood
pulps. Secondary or recycled cellulosic fibers can be obtained from
office waste, newsprint, brown paper stock, and paperboard scrap.
Further, vegetable fibers, such as abaca, flax, milkweed, cotton,
modified cotton, cotton linters, can also be used as the cellulosic
fibers. In addition, synthetic cellulosic fibers such as, for
example, rayon, viscose rayon, and lyocell can be used. Modified
cellulosic fibers are generally composed of derivatives of
cellulose formed by substitution of appropriate radicals (e.g.,
carboxyl, alkyl, acetate, nitrate, etc.) for hydroxyl groups along
the carbon chain. Desirable staple fibers for the purposes of this
application are hydrophilic, such as traditional cellulosic fibers
(a desirable example of which is pulp fibers, as can be found in
rolled tissues and paper-based towels).
[0017] As used herein, the term "substantially continuous fibers"
is intended to mean fibers that have a length that is greater than
the length of staple fibers. The term is intended to include fibers
that are continuous, such as spunbond fibers, and fibers that are
not continuous, but have a defined length greater than about 150
millimeters.
[0018] As used herein "bonded carded webs" or "BOW" refers to
nonwoven webs formed by carding processes as are known to those
skilled in the art and further described, for example, in U.S. Pat.
No. 4,488,928 to Ali Khan et al., which is incorporated herein by
reference thereto. Briefly, carding processes involve starting with
a blend of, for example, staple fibers with bonding fibers or other
bonding components in a bulky ball that is combed or otherwise
treated to provide a generally uniform basis weight. This web is
heated or otherwise treated to activate the adhesive component
resulting in an integrated, usually lofty nonwoven material.
[0019] The basis weight of nonwoven webs is usually expressed in
ounces of material per square yard (osy) or grams per square meter
(gsm) and fiber diameters are usually expressed in microns, or in
the case of staple fibers, denier. It is noted that to convert from
osy to gsm, multiply osy by 33.91.
[0020] As used herein the terms "machine direction" or "MD"
generally refers to the direction in which a material is produced.
It is also often the direction of travel of the forming surface
onto which fibers are deposited during formation of a non-woven
web. The term "cross-machine direction" or "CD" refers to the
direction perpendicular to the machine direction.
[0021] Dimensions measured in the cross-machine direction (CD) are
referred to as "width" dimensions, while dimensions measured in the
machine direction (MD) are referred to as "length" dimensions. The
width and length dimensions of a planar sheet make up the X and Y
directions of the sheet. The dimension in the depth direction of a
planar sheet is also referred to as the Z-direction.
[0022] As used herein, the terms "elastomeric" and "elastic" are
used interchangeably and shall mean a layer, material, laminate or
composite that is generally capable of recovering its shape after
deformation when the deforming force is removed. Specifically, when
used herein, "elastic" or "elastomeric" is meant to be that
property of any material that, upon application of a biasing force,
permits the material to be stretchable to a stretched biased length
that is at least about fifty (50) percent greater than its relaxed
unbiased length, and that will cause the material to recover at
least forty (40) percent of its elongation upon release of the
stretching force. A hypothetical example that would satisfy this
definition of an elastomeric material would be a one (1) inch
sample of a material that is elongatable to at least 1.50 inches
and that, upon being elongated to 1.50 inches and released, will
recover to a length of less than 1.30 inches. Many elastic
materials can be stretched by much more than fifty (50) percent of
their relaxed length, and many of these will recover to
substantially their original relaxed length upon release of the
stretching force.
[0023] As used herein the term "recover" refers to a contraction of
a stretched material upon termination of a biasing force following
stretching of the material by application of the biasing force. For
example, if a material having a relaxed, unbiased length of one (1)
inch was elongated 50 percent by stretching to a length of one and
one half (1.5) inches the material would have a stretched length
that is 150 percent of its relaxed length. If this exemplary
stretched material contracted, that is recovered, to a length of
one and one tenth (1.1) inches, after release of the biasing and
stretching force, the material would have recovered 80 percent (0.4
inch) of its elongation.
[0024] As used herein, the term "g/cc" generally refers to grams
per cubic centimeter.
[0025] As used herein, the term "hydrophilic" generally refers to
fibers or films, or the surfaces of fibers or films that are
wettable by aqueous liquids in contact with the fibers. The term
"hydrophobic" includes those materials that are not hydrophilic as
defined. The phrase "naturally hydrophobic" refers to those
materials that are hydrophobic in their chemical composition state
without additives or treatments affecting the hydrophobicity.
[0026] The degree of wetting of the materials can, in turn, be
described in terms of the contact angles and the surface tensions
of the liquids and materials involved. Equipment and techniques
suitable for measuring the wettability of particular fiber
materials or blends of fiber materials can be provided by the Cahn
SFA-222 Surface Force Analyzer System, or a substantially
equivalent system. When measured with this system, fibers having
contact angles less than 90 are designated "wettable" or
hydrophilic, and fibers having contact angles greater than 90 are
designated "nonwettable" or hydrophobic.
[0027] As used herein, the term "personal care product" refers to
diapers, training pants, absorbent underpants, adult incontinence
products, sanitary wipes and feminine hygiene products, such as
sanitary napkins, pads, and liners, and the like. The term
"absorbent medical product" is employed to refer to products such
as medical bandages, tampons intended for medical, dental,
surgical, and/or nasal use, surgical drapes and garments, coverings
in medical settings, and the like.
[0028] The term "composite" as used herein, refers to a film
material that has been bonded to or otherwise exists with a
nonwoven web including fibers. The film material itself can be
mono-layer, multi-component, or multilayer. The composite can be
apertured and breathable, or the film material of the composite can
be essentially intact.
[0029] The present disclosure describes a non- or low-stretch
bonded (<100% stretch) elastic laminate that includes one or two
external nonwoven layers and an internal plastic layer adjacent to
an internal elastic layer, with adhesive layers between the
nonwoven layers and the film/elastic layers. The film and/or
elastic layers can be in the form of film, strips, strands, etc.
The film can be breathable. The laminate is activated through a
groove rolling or intermeshing gears process.
[0030] The elastic laminate experiences a nearly-complete
fracturing of the nonwoven layers while maintaining the continuity
of the plastic layer. This allows the ability to design the
stress/strain properties of the laminate while also maintaining the
stretch-to-stop requirements for consumer-preferred fit
characteristics. This provides a low cost, soft/gentle, more
underwear-like elastic material for personal care garment
applications.
[0031] Current elastic materials used in products in the global
market are generally based on stretch-bonded elastic laminate
technology with a nonwoven facing. In the stretch-bonded elastic
laminate process, elastic materials (film or strands) are stretched
to 3-5 times their relaxed length before being bonded to facing
materials. Cost analyses of current elastic laminates indicate that
the facing materials, such as spunbond (SB) and
spunbond-meltblown-spunbond (SMS) nonwovens account for more than
50% of the total elastic laminate cost because of the high usage of
facing materials.
[0032] As a result of the work described herein, it was found, for
example, that non-stretch bonded elastic strands combined with a
thin/strong plastic film and facing materials can provide superior
performance with a lower cost than the current stretch-bonded
elastic laminate materials. Furthermore, the non-stretch bonded
elastic laminate of this invention also unexpectedly creates
desirable surface texture and appearance that can provide a more
consumer-preferred appearance in terms of lighter, softer/gentler,
and more cloth-like as underwear.
[0033] More specifically, the elastic laminate of the present
disclosure can include either an elastic strand and a plastic film
non-stretch bonded to a nonwoven, an elastic film and a plastic
strand non-stretch bonded to a nonwoven, or any elastic material
form and any plastic material form non-stretch bonded to a
nonwoven. The elastic and plastic layers can be in the form of
film, strips, strands, etc. The laminate is activated through a
groove rolling process. This elastic laminate provides
consumer-preferred appearance and strength, as well as designable
Stretch-to-Stop (S-S) curves.
[0034] The groove rolling process results in the nearly-complete
fracturing of the nonwoven layers while maintaining the continuity
of the plastic layer. This allows the ability to design the
stress/strain properties of the laminate while also maintaining the
stretch-to-stop requirements for consumer-preferred fit
characteristics. This provides a low cost, soft/gentle, more
underwear-like elastic material for personal care garment
applications.
[0035] In a particular aspect of the present disclosure illustrated
in FIG. 1, an elastic laminate 10 includes a core structure having
a first surface and a second surface, the core structure including
an elastic core layer 20 and a plastic core layer 40. The elastic
core layer 20 is one of a film, a plurality of strands, and a
plurality of strips. The plastic core layer 40 is also one of a
film layer, a plurality of strands, and a plurality of strips. The
elastic core layer 20 and the plastic core layer 40 can be the same
format or of different formats. The plastic core layer 40
reinforces the core structure in the machine direction. The elastic
laminate 10 also includes two low basis weight (.about.8 gsm)
facing materials 70, 80 affixed to the core structure by any
suitable means. In one aspect of the present application, the
facing materials 70, 80 are affixed to the core structure with
adhesive bonding layers 50, 60. In other aspects, the elastic
laminate 10 can be manufactured without one or both facing
materials 70, 80.
[0036] In an alternate aspect of the present disclosure illustrated
in FIG. 2, an elastic laminate 10 includes a core structure having
a first surface and a second surface, the core structure including
an elastic core layer 20 and a plastic core layer 40. The elastic
core layer 20 is one of a film, a plurality of strands, and a
plurality of strips. The plastic core layer 40 is also one of a
film layer, a plurality of strands, and a plurality of strips. The
elastic core layer 20 and the plastic core layer 40 can be the same
format or of different formats. The plastic core layer 40
reinforces the core structure in the machine direction. The elastic
laminate 10 also includes two low basis weight (.about.8 gsm)
facing materials 70, 80 affixed to the core structure by any
suitable means. In one aspect of the present application, the
facing materials 70, 80 are affixed to the core structure with
adhesive bonding layers 50, 60. In other aspects, the elastic
laminate 10 can be manufactured without one or both facing
materials 70, 80.
[0037] Returning to the aspect illustrated in FIG. 1, the elastic
core layer 20 is adhesively bonded to the plastic core layer 40 and
facing materials 70, 80 under little or no elongation (<100%).
After the elastic laminate 10 is made, it has a very little
elasticity and the laminate 10 is not an elastic material at this
point (maximum elongation is less than 20% with minimum tension).
The laminate 10 is then stretched (200-300%) in the machine
direction (MD) using a groove rolling technique, an intermeshing
gears process, or any other suitable process. This stretching
locally tears the facing materials 70, 80, extends the plastic core
layer 40 up to 20-300% depending on processing conditions, and
turns the laminate 10 into a very elastic material with up to
150-250% elongation and with designable tension and S-S curves as
shown in FIG. 3, and as described in more detail below.
[0038] The elastic laminate 10 in this aspect permanently exhibited
a fine regular and periodic three-dimensional structure even under
maximum stretching conditions. In contrast, current stretch-bonded
elastic laminates demonstrate a generally flat surface when under
maximum stretching conditions. The fine three-dimensional surface
structure of the laminate 10 provides a more consumer-preferred
premier appearance and softer/gentler feel. In this aspect, the
plastic core layer 40 functions to provide strength and a
stretch-to-stop property to the elastic laminate 10. The elastic
core layer 20 contributes elastic performance for seal, fit, and
comfort functions when employed in a personal care article. The
facing materials 70, 80 provide a cloth-like appearance to the
elastic laminate 10.
[0039] The film can be either plastic or elastic. One example of a
suitable film includes a high strength and/or extendable plastic
film, whether single or multilayer, incorporated into the laminate
10 to provide a designable tear/poke through strength as well
controllable stretch-to-stop curves for product application and
consumer prefer appearance attributes. Other examples of suitable
films include but are not limited to wrap polyfilm, both
polypropylene (PP)- and polyethylene (PE)-based, breathable outer
cover film, organoclay nanocomposite film, and elastic film.
[0040] The strands and strips can also be plastic or elastic. One
example of a suitable strand material can be a pre-made strand or a
strand extruded from thermoplastic elastomers to provide great
elastic performance. Pre-made strands include LYCRA-brand elastic
strands available from INVISTA, and CREORA-brand elastic fibers
available from Hyosung. Another example of suitable strands is an
extrudable strand including thermoplastic polyurethane (TPU)
available from Huntsman. Other examples of suitable strands include
but are not limited to polypropylene-based thermo elastomer such as
VISTAMAXX-brand elastomer polymers available from ExxonMobil
Chemical, styrenic block copolymer (SBC) such as KRATON-brand SBC
available from Kraton Performance Polymers, and olefin block
copolymers (OBC) such as INFUSE-brand olefin block copolymers
available from Dow Chemical. Similarly, plastic strands can be
either pre-made or extruded from thermoplastic polymers
[0041] The facing materials can be any suitable material including
nonwovens such as tissue, spunbond, meltblown, or any other
suitable cellulose- or polymer-based material. Low basis weight
and/or low strength nonwovens can provide a cloth-like appearance
with softer and gentler touch after activation. All components can
be adhesively laminated or extrusion laminated.
[0042] The adhesive employed to bond the facing materials to the
elastic/plastic layers can be any suitable adhesive.
[0043] In other aspects of the present disclosure, the non-stretch
bonding of the layers of the elastic laminate 10 can be also
accomplished by any other suitable method including, but not
limited to, thermal, ultrasonic, and extrusion lamination
bonding.
[0044] Ring rolling is well known in the art. Examples of
descriptions of the process include those in patent application
EP650714 to Coles et al. entitled "Method of making an absorbent
article using an activatable composite elastic member."
[0045] Non-stretch bonded strand/film elastic laminates as
described herein demonstrate performance enhancements including
premier appearance, gentle and soft feel and touch, increased
strength through strand enforcement, controllable stretch-to-stop
curves (100-250%), and breathable but liquid impermeable
performance. In addition, the elastic laminate 10 described herein
demonstrates a cost that is less than current elastic laminates
because the elastic laminate 10 has a basis weight that can be
reduced to up to 50 percent of the basis weight of current elastic
laminates made from stretch-bonded laminate processes.
[0046] The materials that can be used to form the fibrous nonwoven
web or facing materials 70, 80 include any nonwoven material
capable of performing as described above. For example, the facing
materials 70, 80 can be formed from a blend of a non-elastic
material with an elastic material, one or more non-elastic
materials or a blend of one or more elastic materials with two or
more non-elastic materials. Preferably, the facing materials 70, 80
are formed from a fiber-forming meltblowable or spunbondable
non-elastic gatherable material. However, the facing materials 70,
80 can be formed by depositing a carded web on the surface of the
core structure or by any other method which may be utilized to form
facing materials 70, 80 on the surface of the core structure.
Exemplary fiber-forming materials for use in forming the facing
materials 70, 80 are polyester materials, polyolefin materials or
blends of one or more polyester materials with one or more
polyolefin materials. An exemplary polyester fiber-forming material
is polyethylene terephthalate. An exemplary fiber-forming
polyolefin material is polypropylene. Preferred polypropylene
materials may be obtained from the Himont Company under the trade
designations PC 973 and PF 301.
[0047] After the facing materials 70, 80 have been formed upon or
affixed to the upper surface of the core structure, the composite
nonwoven elastic web 10 is passed through rollers that, for the
reasons stated above, need not be heated or need not apply any
excessive pressure to the core structure. Thereafter, the
stretching and biasing force on the core structure is released so
as to relax and contract the composite nonwoven elastic web 10.
[0048] Reference now will be made in detail to various aspects of
the disclosure, one or more examples of which are set forth below.
Each example is provided by way of explanation, not of limitation
of the disclosure. In fact, it will be apparent to those skilled in
the art that various modifications and variations can be made in
the present disclosure without departing from the scope or spirit
of the disclosure. For instance, features illustrated or described
as part of one aspect, can be used on another aspect to yield a
still further aspect. Thus it is intended that the present
disclosure cover such modifications and variations.
[0049] Preferably, the elastic films used in the present invention
can stretch at least 50%-100% in comparison to its non-stretched
length. In some cases, it is desirable that films can be stretched
up to 100%-200%, 200%-400%, or 400%-600%.
EXAMPLES
Example 1
[0050] Example 1 uses as elastic strands: CREORA 940-brand elastic
fibers at a density of 5 strands/inch, as the plastic film: linear
low-density polyethylene (LLDPE) wrap film with a thickness of 0.6
mil, and as the facing material: 8 gsm meltblown available from
Biax-Fiberfilm Corp. All components were adhesively bonded at
approximately 40% elastic elongation. The laminate was then
activated using a groove rolling machine at Biax-Fiberfilm
Corp.
Example 2
[0051] In Example 2 the elastic material is prepared in the same
way as in Example 1 except that the components were adhesively
bonded at approximately 100% elastic elongation
[0052] Table 1 illustrates basic properties of the non-stretch
bonded strand film laminate of the present disclosure in comparison
to current elastic laminates made from a stretch-bonding process
with spunbond as a facing material, as used for current products.
As illustrated in FIG. 3, the "tension for fit" results indicated
better S-S curves for the elastic material present disclosure and
can provide wider fit product applications with a better tension
control. The strength in terms of tension and stress-to-stop curves
can be adjusted through changing the laminate components such as
the elastic, plastic film, and facing materials as well by
optimizing processing conditions (e.g., engagement of inter
rolling).
TABLE-US-00001 TABLE 1 Comparison of non-stretch bonded elastic
laminate of the present disclosure and typical stretch-bonded
elastic laminate. Non-stretch bonded White DEPEND- Grey DEPEND-
elastic laminate of the brand personal brand personal present
disclosure care article care article X050615-5 Waist Elastics Waist
Elastics Basis Weight (gsm) 64 102 110 Hysteresis Loss (%) 43 45 53
Tensile Peak load (gf) 4928 9005 8448
[0053] The sheet materials produced in accordance with this
disclosure can be used in a variety of end product applications. It
is contemplated that such sheet materials have end product
applications including in the technical areas of filtration,
medical garments, covers, and bandages, and the personal care area,
such as in the ears or side panels of baby/child care diapers, and
adult feminine care applications. Articles made under this
disclosure are very flexible and soft with a cloth-like feel.
[0054] In a first particular aspect, a laminate includes a core
structure having a first surface and a second surface, the core
structure including an elastic core layer and a plastic core layer,
wherein the elastic core layer is one of a film, a plurality of
strands, and a plurality of strips, and wherein the plastic core
layer is one of a film layer, a plurality of strands, and a
plurality of strips, the plastic core layer reinforcing the core
structure in the machine direction; and a nonwoven first facing
layer affixed to the first surface.
[0055] A second particular aspect includes the first particular
aspect, wherein the plurality of strands is disposed between the
film layer and the first facing layer.
[0056] A third particular aspect includes the first and/or second
aspect, wherein the first facing layer is affixed to the first
surface with adhesive.
[0057] A fourth particular aspect includes one or more of aspects
1-3, further comprising a nonwoven second facing layer affixed to
the second surface.
[0058] A fifth particular aspect includes one or more of aspects
1-4, wherein the nonwoven first facing layer is
cellulose-based.
[0059] A sixth particular aspect includes one or more of aspects
1-5, wherein the nonwoven first facing layer is polymer-based.
[0060] A seventh particular aspect includes one or more of aspects
1-6, wherein the nonwoven first layer includes polymer and
cellulose.
[0061] An eighth particular aspect includes one or more of aspects
1-7, wherein the plastic core layer is a film, and wherein the
elastic core layer is a plurality of strands or a plurality of
strips.
[0062] A ninth particular aspect includes one or more of aspects
1-8, wherein the elastic core layer is a film, and wherein the
plastic core layer is a plurality of strands or a plurality of
strips.
[0063] In a tenth particular aspect, a method for producing a
composite nonwoven elastic web comprising an elastic web joined to
a fibrous nonwoven web includes providing an elastic web comprising
a core structure having an elastic core layer and a plastic core
layer, wherein the elastic web has a first surface and a second
surface; stretching the elastic web to less than 100 percent
stretch; affixing a fibrous nonwoven web to the first surface of
the stretched elastic web to form a composite nonwoven elastic web;
relaxing the composite nonwoven elastic web; and activating the
nonwoven elastic web.
[0064] An eleventh particular aspect includes the tenth particular
aspect, wherein activating includes using a groove rolling process
or an intermeshing gears process.
[0065] A twelfth particular aspect includes the tenth and/or
eleventh aspect, wherein the elastic core layer is one of a film, a
plurality of strands, and a plurality of strips, wherein the
plastic core layer is one of a film layer, a plurality of strands,
and a plurality of strips.
[0066] A thirteenth particular aspect includes one or more of
aspects 10-12, wherein the elastic core layer is a film, and
wherein the plastic core layer is a plurality of strands or a
plurality of strips.
[0067] A fourteenth particular aspect includes one or more of
aspects 10-13, wherein the plastic core layer is a film, and
wherein the elastic core layer is a plurality of strands or a
plurality of strips.
[0068] A fifteenth particular aspect includes one or more of
aspects 10-14, wherein the fibrous nonwoven web is affixed to the
elastic web with a thermal, adhesive, ultrasonic, or co-extrusion
lamination method.
[0069] A sixteenth particular aspect includes one or more of
aspects 10-15, further comprising affixing a second fibrous
nonwoven web to the second surface.
[0070] A seventeenth particular aspect includes one or more of
aspects 10-16, wherein the fibrous nonwoven web is
cellulose-based.
[0071] An eighteenth particular aspect includes one or more of
aspects 10-17, wherein the fibrous nonwoven web is
polymer-based.
[0072] A nineteenth particular aspect includes one or more of
aspects 10-18, wherein the fibrous nonwoven web includes polymer
and cellulose.
[0073] In a twentieth particular aspect, a method for producing a
composite nonwoven elastic web including an elastic web joined to a
fibrous nonwoven web includes providing an elastic web comprising a
core structure having an elastic core layer and a plastic core
layer, wherein the elastic web has a first surface and a second
surface, wherein the elastic core layer is a film, and wherein the
plastic core layer is a plurality of strands or a plurality of
strips; stretching the elastic web to less than 100 percent
stretch; affixing a fibrous nonwoven web to the first surface of
the stretched elastic web to form a composite nonwoven elastic web,
the fibrous nonwoven web including polymeric and/or cellulosic
fibers; relaxing the composite nonwoven elastic web; and activating
the nonwoven elastic web using a groove rolling process or an
intermeshing gears process.
[0074] While the disclosure has been described in detail with
respect to the specific aspects thereof, it will be appreciated
that those skilled in the art, upon attaining an understanding of
the foregoing, can readily conceive of alterations to, variations
of, and equivalents to these aspects. Accordingly, the scope of the
present disclosure should be assessed as that of the appended
claims and any equivalents thereto.
* * * * *