U.S. patent application number 11/456915 was filed with the patent office on 2008-01-17 for post conversion nonwovens processing.
Invention is credited to Gregory van Buskirk, David Jackson Lestage, Marc Privitera, Jason White.
Application Number | 20080014818 11/456915 |
Document ID | / |
Family ID | 38949821 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080014818 |
Kind Code |
A1 |
Privitera; Marc ; et
al. |
January 17, 2008 |
POST CONVERSION NONWOVENS PROCESSING
Abstract
A method of treated a nonwoven substrate after the normal
conversion process to generate modification to the Z dimension. The
method can be accomplished either before or after placing the
substrate in a consumer container. The method can be accomplished
by the consumer. The treatment can be the application of heat to
increase the thickness of the substrate. The result can be a
product combination of a canister containing a roll of wipes where
the thickness of the wipes is enhanced prior to loading with a
cleaning formulation.
Inventors: |
Privitera; Marc; (Walnut
Creek, CA) ; Lestage; David Jackson; (Livermore,
CA) ; Buskirk; Gregory van; (Danville, CA) ;
White; Jason; (Pleasanton, CA) |
Correspondence
Address: |
THE CLOROX COMPANY
P.O. BOX 24305
OAKLAND
CA
94623-1305
US
|
Family ID: |
38949821 |
Appl. No.: |
11/456915 |
Filed: |
July 12, 2006 |
Current U.S.
Class: |
442/213 |
Current CPC
Class: |
D04H 1/06 20130101; Y10T
442/326 20150401 |
Class at
Publication: |
442/213 |
International
Class: |
D03D 15/00 20060101
D03D015/00 |
Claims
1. A product combination for delivering a nonwoven product to a
consumer comprising; a. a consumer container; and b. a roll of
nonwoven substrate; c. wherein the nonwoven substrate has a
Z-dimension thickness A when placed in the consumer container; d.
wherein the nonwoven substrate is treated in the consumer container
to modify the Z-dimension thickness to give a Z-dimension thickness
B; e. wherein the Z-dimension thickness B is greater than the
Z-dimension thickness A as a result of the treatment operation; and
f. wherein the treatment operation is not adding a liquid to the
substrate in the consumer container.
2. The product combination of claim 1, wherein the treatment
operation is heating the substrate.
3. The product combination of claim 1, wherein the heating is
provided by microwave energy.
4. The product combination of claim 1, wherein the substrate is
sold to the consumer in dry form.
5. The product combination of claim 1, wherein the substrate is
sold to the consumer in wet form.
6. A method of increasing the Z-dimension thickness of a nonwoven
substrate used for a cleaning wipe comprising: a. slitting the
substrate; and b. heating the substrate resulting in a modification
of the Z-dimension of the substrate.
7. The method of claim 6; wherein the substrate is heated in a
consumer container resulting in an increase in the Z-dimension
thickness of the substrate.
8. The method of claim 7; wherein the heating is provided by
microwave energy.
9. The method of claim 7; wherein the substrate in the consumer
container is in sheet form.
10. The method of claim 7; wherein the substrate in the consumer
container is in roll form.
11. The method of claim 7; wherein the substrate is individually
packaged.
12. The method of claim 6; wherein the substrate is sold to the
consumer in dry form.
13. The method of claim 6; wherein the substrate is sold to the
consumer in wet form.
14. The method of claim 6; wherein the substrate is heated
resulting in an increase in Z-dimension thickness of the substrate
before placing the substrate in a consumer container.
15. The method of claim 6; wherein the consumer heats the
substrate.
16. A method of modifying a specific attribute of a nonwoven
substrate comprising: a. placing the substrate in a consumer
container; b. treating the substrate to modify the specific
attribute; c. wherein the treatment is not adding a liquid to the
substrate in the consumer container.
17. The method of claim 16; wherein the substrate in the consumer
container is in sheet form.
18. The method of claim 16; wherein the substrate in the consumer
container is in roll form.
19. The method of claim 16; wherein the substrate is sold to the
consumer in dry form.
20. The method of claim 15; wherein the substrate is sold to the
consumer in wet form.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to manufacturing
post-treatment of nonwoven substrates. The present invention
relates generally to consumer post- treatment of nonwoven
substrates. The invention also relates to treatment of nonwoven
substrates in consumer packaging containers. The invention also
relates to cleaning substrates, cleaning heads, cleaning pads,
cleaning sponges and related systems.
[0003] 2. Description of the Related Art
[0004] U.S. Pat. App. 2004/0106345 to Zafiroglu discloses a
laminated multilayer textured composite formed by a simultaneous
pressure embossing and thermal laminating process. U.S. Pat. No.
6,809,048 to Jacobs discloses a heating process for forming a
three-dimensional nonwoven laminate. U.S. Pat. No. 6,561,354 to
Fereshtehkhou et al. describes a three-dimensional cleaning sheet
formed when a contractable scrim material is heated and then
cooled. U.S. Pat. No. 6,723,416 to Groitzsch et al. discloses a
three-dimensional nonwoven formed from a heated shrinkage process.
U.S. Pat. No. 6,774,070 to Kenmochi et al. discloses a nonwoven
from core-sheath fibers. U.S. Pat. No. 6,187,699 to Terakawa et al.
discloses nonwoven laminated by thermal fusion of the layers. U.S.
Pat. No. 6,506,695 to Gardner et al. discloses a nonwoven web and
film laminate with deformations in the film formed by heat and
pressure. U.S. Pat. No. 6,270,875 to Nissing discloses a multilayer
wipe that changes thickness when wetted.
[0005] These processes generally form a textured substrate while
the substrate is moving along the production line in a continuous
fashion. The increase in texture comes at a sacrifice to line
speed, since generally the line must run at a slower speed in order
to control the texturing operation. It is therefore an object of
the present invention to provide a nonwoven substrate that
overcomes the disadvantages and shortcomings associated with prior
art substrates and related systems.
SUMMARY OF THE INVENTION
[0006] In accordance with the above objects and those that will be
mentioned and will become apparent below, one aspect of the present
invention comprises a product combination for delivering a nonwoven
product to a consumer comprising; [0007] a. a consumer container;
and [0008] b. a roll of nonwoven substrate; [0009] c. wherein the
nonwoven substrate has a Z-dimension thickness A when placed in the
consumer container; [0010] d. wherein the nonwoven substrate is
treated in the consumer container to modify the Z-dimension
thickness to give a Z-dimension thickness B. [0011] e. wherein the
Z-dimension thickness B is greater than the Z-dimension thickness A
as a result of the treatment operation; and [0012] f. wherein the
treatment operation is not adding a liquid to the substrate in the
consumer container.
[0013] In accordance with the above objects and those that will be
mentioned and will become apparent below, another aspect of the
present invention comprises a method of increasing the Z-dimension
thickness of a nonwoven substrate used for a cleaning wipe
comprising: [0014] a. slitting the substrate; and [0015] b. heating
the substrate resulting in a modification of the Z-dimension of the
substrate.
[0016] In accordance with the above objects and those that will be
mentioned and will become apparent below, another aspect of the
present invention comprises a method of modifying a specific
attribute of a nonwoven substrate comprising: [0017] a. placing the
substrate in a consumer container; and [0018] b. treating the
substrate to modify the specific attribute; [0019] c. wherein the
treatment is not adding a liquid to the substrate in the consumer
container.
[0020] Further features and advantages of the present invention
will become apparent to those of ordinary skill in the art in view
of the detailed description of preferred embodiments below, when
considered together with the attached claims.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Before describing the present invention in detail, it is to
be understood that this invention is not limited to particularly
exemplified systems or process parameters that may, of course,
vary. It is also to be understood that the terminology used herein
is for the purpose of describing particular embodiments of the
invention only, and is not intended to limit the scope of the
invention in any manner.
[0022] All publications, patents and patent applications cited
herein, whether supra or infra, are hereby incorporated by
reference in their entirety to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated by
reference.
[0023] As used herein and in the claims, the term "comprising" is
inclusive or open-ended and does not exclude additional unrecited
elements, compositional components, or method steps. Accordingly,
the term "comprising" encompasses the more restrictive terms
"consisting essentially of" and "consisting of".
[0024] It must be noted that, as used in this specification and the
appended claims, the singular forms "a," "an" and "the" include
plural referents unless the content clearly dictates otherwise.
Thus, for example, reference to a "surfactant" includes two or more
such surfactants.
[0025] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the invention pertains. Although
a number of methods and materials similar or equivalent to those
described herein can be used in the practice of the present
invention, the preferred materials and methods are described
herein.
[0026] In the application, effective amounts are generally those
amounts listed as the ranges or levels of ingredients in the
descriptions, which follow hereto. Unless otherwise stated, amounts
listed in percentage ("%'s") are in weight percent (based on 100%
active) of the cleaning composition alone, not accounting for the
substrate weight. Each of the noted cleaner composition components
and substrates is discussed in detail below.
[0027] As used herein, the term "substrate" is intended to include
any material that is used to treat a surface, for example, to clean
an article or a surface. A wide variety of materials can be used as
the substrate. The substrate should have sufficient wet strength,
abrasivity, loft and porosity. Examples of suitable substrates
include, nonwoven substrates, wovens substrates, hydroentangled
substrates, foams and sponges. The substrate can be attached to a
cleaning implement, such as a floor mop, handle, or a hand held
cleaning tool, such as a toilet-cleaning device.
[0028] As used herein the term "polymer" generally includes but is
not limited to, homopolymers, copolymers, such as for example,
block, graft, random and alternating copolymers, terpolymers, etc.
and blends and modifications thereof. Furthermore, unless otherwise
specifically limited, the term "polymer" shall include all possible
geometrical configurations of the material. These configurations
include, but are not limited to isotactic, syndiotactic and random
symmetries. As used herein the term "thermoplastic" or
"thermoplastic polymer" refers to polymers that will soften and
flow or melt when heat and/or pressure are applied, the changes
being reversible.
[0029] As used herein, "film" refers to a polymer film including
flat nonporous films, and porous films such as microporous,
nanoporous, closed or open celled, breathable films, or apertured
films.
[0030] As used herein, the term "fiber" includes both staple
fibers, i. e., fibers which have a defined length between about 2
and about 20 mm, fibers longer than staple fiber but are not
continuous, and continuous fibers, which are sometimes called
"continuous filaments" or simply "filaments". The method in which
the fiber is prepared will determine if the fiber is a staple fiber
or a continuous filament.
[0031] As used herein, where a nonwoven includes fibers, the terms
"nonwoven" or "nonwoven substrate" means a substrate having a
structure of individual fibers or threads which are interlaid, but
not in an identifiable manner as in a knitted web. Nonwoven
substrates also include films. Nonwoven substrates have been formed
from many processes, such as, for example, meltblowing processes,
spunbonding processes, and bonded carded web processes. The basis
weight of nonwoven substrates is usually expressed in ounces of
material per square yard (osy) or grams per square meter (gsm) and
the fiber diameters useful 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.
[0032] The term "denier" is defined as grams per 9000 meters of a
fiber. For a fiber having circular cross-section, denier may be
calculated as fiber diameter in microns squared, multiplied by the
density in grams/cc, multiplied by 0.00707. A lower denier
indicates a finer fiber and a higher denier indicates a thicker or
heavier fiber. Outside the United States the unit of measurement is
more commonly the "tex," which is defined as the grams per
kilometer of fiber. Tex may be calculated as denier divided by 9.
The "mean fiber denier" is the sum of the deniers for each fiber,
divided by the number of fibers.
[0033] As used herein, the term "bulk density" refers to the weight
of a material per unit of volume and is generally expressed in
units of mass per unit bulk volume (e.g., grams per cubic
centimeter).
[0034] As used herein, the term "spunbonded fibers" refers to
fibers which are formed by extruding molten thermoplastic material
as filaments from a plurality of fine, usually circular capillaries
of a spinneret with the diameter of the extruded filaments then
being rapidly reduced as by, for example, U.S. Pat. No. 4,340,563
to Appel et al., and 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. Nos. 3,338,992
and 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman; U.S.
Pat. No. 3,542,615 to Dobo et al.; and U.S. Pat. No. 5,382,400 to
Pike et al.; the entire content of each is incorporated herein by
reference. Spunbond fibers are generally not tacky when they are
deposited onto a collecting surface. Spunbond fibers are generally
continuous and have average diameters (from a sample of at least
10) larger than 7 microns to about 50 or 60 microns, often, between
about 15 and 25 microns.
[0035] As used herein, the term "meltblown fibers" means fibers
formed by extruding a molten thermoplastic material through a
plurality of fine, usually circular, die capillaries as molten
threads or filaments into converging high velocity, usually hot,
gas (e.g. air) streams which attenuate the filaments of molten
thermoplastic material to reduce their diameter, which may 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.
Meltblown fibers can be microfibers, which may be continuous or
discontinuous, and are generally smaller than 10 microns in average
diameter, and are generally tacky when deposited onto a collecting
surface.
[0036] As used herein, the term "conjugate fibers" refers to fibers
or filaments that have been formed from at least two polymers
extruded from separate extruders but spun together to form one
fiber. Conjugate fibers are also sometimes referred to as
"multicomponent" or "bicomponent" fibers or filaments. The term
"bicomponent" means that there are two polymeric components
making-up the fibers. The polymers are usually different from each
other though conjugate fibers may be prepared from the same
polymer, but the polymers are different from one another in some
physical property, such as, for example, melting point or the
softening point. The polymers are arranged in substantially
constantly positioned distinct zones across the cross-section of
the multicomponent fibers or filaments and extend continuously
along the length of the multicomponent fibers or filaments. The
configuration of such a multicomponent fiber may be, for example, a
sheath/core arrangement, wherein one polymer is surrounded by
another, a side-by-side arrangement, a pie arrangement or an
"islands-in-the-sea" arrangement. Multicomponent fibers are taught
in U.S. Pat. No. 5,108,820 to Kaneko et al., U.S. Pat. No.
5,336,552 to Strack et al., and U.S. Pat. No. 5,382,400 to Pike et
al., the entire content of each is incorporated herein by
reference. For two component fibers or filaments, the polymers may
be present in ratios of 75/25, 50/50, 25/75 or any other desired
ratios.
[0037] As used herein, the term "multiconstituent fibers" refers to
fibers that have been formed from at least two polymers extruded
from the same extruder as a blend or mixture. Multiconstituent
fibers do not have the various polymer components arranged in
relatively constantly positioned distinct zones across the
cross-sectional area of the fiber and the various polymers are
usually not continuous along the entire length of the fiber,
instead usually forming fibrils or protofibrils which start and end
at random.
[0038] As used herein "carded webs" 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
Alikhan and Schmidt, which is incorporated herein in its entirety
by reference. Briefly, carding processes involve starting with
staple fibers in a bulky batt that is combed or otherwise treated
to provide a web of generally uniform basis weight. As used herein
"Bonded carded web" refers to webs that are made from staple fibers
which are sent through a combing or carding unit, which breaks
apart and aligns the staple fibers in the machine direction to form
a generally machine direction-oriented fibrous nonwoven web. Such
fibers are usually purchased in bales and are placed in a picker,
which separates the fibers prior to the carding unit. Once the web
is formed, it then is bonded by one or more of several known
bonding methods. One such bonding method is powder bonding, wherein
a powdered adhesive is distributed through the web and then
activated, usually by heating the web and adhesive with hot air.
Another suitable bonding method is pattern bonding, wherein heated
calender rolls or ultrasonic bonding equipment are used to bond the
fibers together, usually in a localized bond pattern, though the
web can be bonded across its entire surface if so desired. Another
suitable and well-known bonding method, particularly when using
conjugate staple fibers, is through-air bonding.
[0039] As used herein, the term "hot air knife" or HAK means a
process of bonding a just produced web, particularly spunbond, in
order to give it sufficient integrity, i.e. increase the strength
of the web, for further processing. A hot air knife is a device
which focuses a stream of heated air at a very high flow rate,
generally from about 1000 to about 10000 feet per minute (fpm) (305
to 3050 meters per minute), or more particularly from about 3000 to
5000 feet per minute (915 to 1525 m/min.) directed at the nonwoven
web after its formation. The air temperature is usually in the
range of the melting point of at least one of the polymers used in
the web, generally between about 200 and 550.degree. F. (93 and
290.degree. C.) for the thermoplastic polymers commonly used in
spunbonding. The control of air temperature, velocity, pressure,
volume and other factors helps avoid damage to the web while
increasing its integrity. The HAK process has a great range of
variability and controllability of many factors such as air
temperature, velocity, pressure, volume, slot or hole arrangement
and size, and the distance from the HAK plenum to the web.
[0040] As used herein, through-air bonding or "TAB" means a process
of bonding a nonwoven bicomponent fiber web in which air, which is
sufficiently hot to melt one of the polymers of which the fibers of
the web are made is forced through the web. The air velocity is
between 100 and 500 feet per minute and the dwell time may be as
long as 6 seconds. The melting and resolidification of the polymer
provides the bonding. Through air bonding has relatively restricted
variability and since through-air bonding TAB requires the melting
of at least one component to accomplish bonding and is therefore
particularly useful in connection with webs with two components
like conjugate fibers or those which include an adhesive. In the
through-air bonder, air having a temperature above the melting
temperature of one component and below the melting temperature of
another component is directed from a surrounding hood, through the
web, and into a perforated roller supporting the web.
Alternatively, the through-air bonder may be a flat arrangement
wherein the air is directed vertically downward onto the web. The
operating conditions of the two configurations are similar, the
primary difference being the geometry of the web during bonding.
The hot air melts the lower melting polymer component and thereby
forms bonds between the filaments to integrate the web.
[0041] As used herein, "ultrasonic bonding" means a process
performed, for example, by passing the fabric between a sonic horn
and anvil roll as illustrated in U.S. Pat. No. 4,374,888 to
Bornslaeger. As used herein "thermal point bonding" involves
passing one or more layers to be bonded between a heated engraved
pattern roll and a smooth calender roll. The engraved roll is,
patterned in some way so that the entire fabric is not bonded over
its entire surface, and the anvil roll is usually flat. As a
result, various patterns for engraved rolls have been developed for
functional as well as aesthetic reasons. One example of a pattern
has points and is the Hansen Pennings or "H &P" pattern with
about a 30% bond area when new and with about 200 bonds/square inch
as taught in U.S. Pat. No. 3,855,046 to Hansen and Pennings. The H
&P pattern has square point or pin bonding areas wherein each
pin has a side dimension of 0.038 inches (0.965 mm), a spacing of
0.070 inches (1.778 mm) between pins, and a depth of bonding of
0.023 inches (0.584 mm). The resulting pattern has a bonded area of
about 29.5% when new. Another typical point bonding pattern is the
expanded Hansen Pennings or "EHP" bond pattern, which produces a
15% bond area when new with a square pin having a side dimension of
0.037 inches (0.94 mm), a pin spacing of 0.097 inches (2.464 mm)
and a depth of 0.039 inches (0.991 mm). Another typical point
bonding pattern designated "714" has square pin bonding areas
wherein each pin has a side dimension of 0.023 inches, a spacing of
0.062 inches (1.575 mm) between pins, and a depth of bonding of
0.033 inches (0.838 mm). The resulting pattern has a bonded area of
about 15% when new. Yet another common pattern is the C-Star
pattern, which has, when new, a bond area of about 16.9%. The
C-Star pattern has a cross-directional bar or "corduroy" design
interrupted by shooting stars. Other common patterns include a
diamond pattern with repeating and slightly offset diamonds with
about a 16% bond area and a wire weave pattern looking as the name
suggests, e.g. like a window screen, with about a 15% bond area.
Typically, the percent bonding area varies from around 10% to
around 30% of the area of the fabric laminate web. As is well known
in the art, the spot bonding holds the laminate layers together as
well as imparts integrity to each individual layer by bonding
filaments and/or fibers within each layer.
[0042] As used hereing "airlaying" or "airlaid" is a well-known
process by which a fibrous nonwoven layer can be formed. In the
airlaying process, bundles of small fibers having typical lengths
ranging from about 3 to about 52 millimeters (mm) are separated and
entrained in an air supply and then deposited onto a forming
screen, usually with the assistance of a vacuum supply. The
randomly deposited fibers then are bonded to one another using, for
example, hot air to activate a binder component or a latex
adhesive. Airlaying is taught in, for example, U.S. Pat. No.
4,640,810 to Laursen et al., and U.S. Pat. No. 5,885,516 to
Christensen.
[0043] The term "sponge", as used herein, is meant to mean an
elastic, porous material, including, but not limited to, compressed
sponges, cellulosic sponges, reconstituted cellulosic sponges,
cellulosic materials, foams from high internal phase emulsions,
such as those disclosed in U.S. Pat. No. 6,525,106, polyethylene,
polypropylene, polyvinyl alcohol, polyurethane, polyether, and
polyester sponges, foams and nonwoven materials, and mixtures
thereof.
[0044] As used herein, the term "machine direction" or MD means the
length of a fabric in the direction in which it is produced. The
term "cross machine direction" or CD means the width of fabric,
i.e. a direction generally perpendicular to the MD.
[0045] As used herein, the term "Z-dimension" refers to the
dimension orthogonal to the length and width of the cleaning sheet
of the present invention, or a component thereof. The Z-dimension
usually corresponds to the thickness of the sheet. As used herein,
the term "X-Y dimension" refers to the plane orthogonal to the
thickness of the cleaning sheet, or a component thereof. The X and
Y dimensions usually correspond to the length and width,
respectively, of the sheet or a sheet component. In one embodiment
of the invention, the substrates undergo processing to expand the
fibrous web in the z-direction to increase the bulk and thickness
of the web while maintain a low basis weight. The Z-direction
expansion of the substrates of the present invention may reduce the
density of the web in two dissimilar ways: overall density and
localized density. Overall density is calculated by, 1) measuring
the overall caliper of the web over a large area (i.e. .about.25
cm.sup.2), and 2) dividing the basis weight (in grams per cm.sup.2)
by the caliper (in cm) to yield the density in g/cc. Localized
density is determined in a similar manner except that the caliper
is the average of the thinnest portion of the web measured
perpendicular to the surface of said web portion.
[0046] The caliper of a substrate is a measure of its thickness.
The overall caliper of a substrate is a measurement of the highest
to lowest point on a substrate and the local caliper is a
measurement of the thickness of the substrate at a given point. The
substrate of the present invention may be flat, where the local
caliper is substantially equal to the overall caliper or it may be
textured where the local caliper and the overall caliper have
substantially different values. In a preferred embodiment of the
invention, the fibrous web has a local caliper that is less than
about 10% to 75% of the overall caliper. The overall caliper
measurement was performed at a pressure of 0.01 psi. Any caliper
measurement equipment capable of measuring at this pressure should
be suitable for measuring the overall caliper. The SDL Atlas
Digital Thickness Gauge, Model # M034A is another effective tool
for measuring these calipers. The local caliper is best measured
using a microscope without applying any pressure to the substrate.
Thickness A is the substrate thickness prior to final processing
and thickness B is the substrate thickness after final processing,
as defined herein.
[0047] Various processes can be utilized to achieve Z-direction
expansion. One type of process decreases both overall density and
local density. A second set of processes decreases the overall
density without significantly altering the local density. Processes
that belong to the first group include, but are not limited to,
bulking via abrasion, air texturing, heat activation to bulk by
gathering with blends of fibers and/or bicomponent fibers, or
combinations thereof. Processes that belong to the second group
move the fibrous web center-line out of the X-Y dimension and
include, but are not limited to: thermoforming, bicomponent heat
shrinking, convoluted forming wires, male-male mated rolls,
embossing rolls, "SpaceNet", ring-rolling, SELFing, and/or
combinations thereof.
[0048] The processes for thermoforming, using forming wires or
forming surfaces to create texture in a non-woven is well known in
the art. The non-woven materials formed around a textured wire or
forming surface using heat to shape the fibers into place.
Similarly, embossing or heated male-male mated rolled with
interlocking dual pin rolls use heat and/or pressure to create
textured non-woven materials and are also widely used in the
art.
[0049] As used herein, the term "layer" refers to a member or
component of a cleaning sheet whose primary dimension is X-Y, i.e.,
along its length and width. It should be understood that the term
layer is not necessarily limited to single layers or sheets of
material. Thus the layer can comprise laminates or combinations of
several sheets or webs of the requisite type of materials.
Accordingly, the term "layer" includes the terms "layers" and
"layered."
[0050] For purposes of the present invention, an "upper" layer of a
cleaning sheet is a layer that is relatively further away from the
surface that is to be cleaned (i.e., in the implement context,
relatively closer to the implement handle during use). The term
"lower" layer conversely means a layer of a cleaning sheet that is
relatively closer to the surface that is to be cleaned (i.e., in
the implement context, relatively further away from the implement
handle during use).
[0051] The term "cleaning composition", as used herein, is meant to
mean and include a cleaning formulation having at least one
surfactant.
[0052] The term "surfactant", as used herein, is meant to mean and
include a substance or compound that reduces surface tension when
dissolved in water or water solutions, or that reduces interfacial
tension between two liquids, or between a liquid and a solid. The
term "surfactant" thus includes anionic, nonionic and/or amphoteric
agents.
[0053] As used herein, the term "garment" means any type of
non-medically oriented apparel which may be worn. This includes
industrial work wear and coveralls, undergarments, pants, shirts,
jackets, gloves, socks, and the like.
[0054] As used herein, the term "infection control product" means
medically oriented items such as surgical gowns and drapes, face
masks, head coverings like bouffant caps, surgical caps and hoods,
footwear like shoe coverings, boot covers and slippers, wound
dressings, bandages, sterilization wraps, wipers, garments like lab
coats, coveralls, aprons and jackets, patient bedding, stretcher
and bassinet sheets, industrial coveralls, and the like.
[0055] As used herein, the term "personal care product" means
diapers, training pants, absorbent underpants, adult incontinence
products, and feminine hygiene products.
Post-Treatment
[0056] The substrate may be post-treated in a roll, in stacks of
individual sheets, or after forming individual structures, such as
diapers or mitts. The substate may be post-treated after it has
been slit and is still on the process line. The substate may be
post-treated after it has been placed in a packaging or consumer
use container. The substrate may be post-treated by the
consumer.
[0057] One suitable form of post-treatment is heating the
substrate. The substrate can be heated by a variety of forms of
energy. Suitable forms of energy include, but are not limited to,
heat, ultrasound, electromagnetic, hydrodynamic, and aerodynamic
energy. Types of electromagnetic energy forms include but are not
limited to ultraviolet light, infrared light, radio-frequency
waves, microwaves, and electron beam. The post-treatment of the
substrate results in activation of the substrate to modify a
specific attribute of the substrate. Types of activation of
components of starting substrate include, but are not limited to,
melting, cross-linking, polymerization, chemical bonding, and ionic
bonding. In a suitable embodiment, rolls or sheets or individual
items of substrate are heated to about the melting temperature of
one of the components of the starting substrate. After the heated
substrate has cooled, a specific attribute of the substrate, such
as thickness, has been modified. The final attribute may differ
along the substrate depending upon the substrate properties, for
example, the bonding pattern.
Nonwoven Substrate and Processing
[0058] In one embodiment, the substrate of the present invention
comprises a nonwoven substrate or web. The substrate is composed of
nonwoven fibers or paper. The term nonwoven is to be defined
according to the commonly known definition provided by the
"Nonwoven Fabrics Handbook" published by the Association of the
Nonwoven Fabric Industry. A paper substrate is defined by EDANA
(note 1 of ISO 9092-EN 29092) as a substrate comprising more than
50% by mass of its fibrous content is made up of fibers (excluding
chemically digested vegetable fibers) with a length to diameter
ratio of greater than 300, and more preferably also has density of
less than 0.040 g/cm.sup.3. The definitions of both nonwoven and
paper substrates do not include woven fabric or cloth or sponge.
The substrate can be partially or fully permeable to water. The
substrate can be flexible and the substrate can be resilient,
meaning that once applied external pressure has been removed the
substrate regains its original shape.
[0059] The substrates of the present invention are formed by any of
the following processes: carding, airlaid, spunbond, meltblown,
coform, wetlaid, and mixtures thereof. The substrates of the
present invention are consolidated by any of the following
processes: hydroentanglement, thermal calender bonding, through air
thermal bonding, chemical bonding, needlepunching, and mixtures
thereof. The air-laying process is described in U.S. Pat. App.
2003/0036741 to Abba et al. and U.S. Pat. App. 2003/0118825 to
Melius et al. The resulting layer, regardless of its method of
production or composition, is then subjected to at least one of
several types of bonding operations to anchor the individual fibers
together to form a self-sustaining substrate. In the present
invention the nonwoven substrate can be prepared by a variety of
processes including, but not limited to, air-entanglement,
hydroentanglement, thermal bonding, and combinations of these
processes.
[0060] Additionally, the first layer and the second layer, as well
as additional layers, when present, can be bonded to one another in
order to maintain the integrity of the article. The layers can be
heat spot bonded together or using heat generated by ultrasonic
sound waves. The bonding may be arranged such that geometric shapes
and patterns, e.g. diamonds, circles, squares, etc., are created on
the exterior surfaces of the layers and the resulting article.
[0061] The bonding pattern can be chosen in order to maximize
stiffness of the substrate. This applies in particular when bonding
is effected by adhesive (chemical, such as epoxy resin adhesive, or
other adhesive) or by ultrasound. Thermal or pressure bonding can
be used if the layers to be bonded are appropriate for this. One
suitable bonding pattern is application of adhesive or ultrasonic
bonding across the full area of the substrate. Generally such
patterns do not take up substantially the entire area, sometimes
not more than 20%, sometimes not more than 15%, but sometimes at
least 5%, of the area of the substrate is covered by bonds.
[0062] One suitable application pattern for adhesive, ultrasonic or
other bonds is in the form of a number of stripes extending across
the width of the substrate. Suitably the stripes are parallel. The
direction can be chosen depending upon the direction in which
stiffness is desired. For instance, if stiffness in the machine
direction (this direction being defined in relation to the
manufacturing process for the substrate) is desired, i.e. it is
desired to make folding along a line extending in the transverse
direction more difficult, then the stripes can extend in the
machine direction. Conversely, if transverse direction stiffness is
desired, then stripes extending in the transverse direction can be
provided. A particularly bonding pattern is one of two sets of
parallel stripes at different angles, for instance in cross-hatch
form. Such systems can provide the effect of introduction of a net
between two layers.
[0063] The above patterns for improvement of stiffness are useful
when applied to adhesive or ultrasound bonding. However, such
patterns can alternatively be applied using hot melt polymer
printed onto the substrate, either between layers or on an exterior
surface of one of the layers. Such patterns can be applied using
any low melting polymer that is flexible after application and
drying and capable of producing a continuous film. Suitable
polymers include polyethylene. Application of hot melt polymer can
be for instance by screen or gravure printing. Screen printing is
preferred. Application of hot melt polymer can be on an exterior
surface on one of the layers.
[0064] Bonding can be effected after all layers intended to form
the substrate have been assembled. In some embodiments, however,
two or more layers can be pre-bonded prior to contacting these
layers with additional layers to form the substrate.
[0065] The stiffness of the substrate when wet is an important
feature. Stiffness is expressed in Taber stiffness units,
preferably measured in accordance with ASTM D-5650 (resistance to
bending of paper of low bending stiffness). Stiffness of the
substrate when dry is measured before it is used for cleaning a
surface. Stiffness of the substrate when wet is measured after it
has been saturated in water. Stiffness when dry can be at least 5,
or at least 8 Taber stiffness units. In particularly cases,
stiffness when dry is at least 9 Taber stiffness units. The Taber
stiffness when wet can be at least 5 or at least 8. In particular
embodiments, the stiffness when wet can be at least 9 Taber
stiffness units. Particular embodiments have stiffness when wet at
least 50% or at least 60% or at least 80% or at least 90% of
stiffness when dry.
[0066] The substrate can include both natural and synthetic fibers.
The substrate can also include water-soluble fibers or
water-dispersible fibers, from polymers described herein. The
substrate can be composed of suitable unmodified and/or modified
naturally occurring fibers including cotton, Esparto grass,
bagasse, hemp, flax, silk, wool, wood pulp, chemically modified
wood pulp, jute, ethyl cellulose, and/or cellulose acetate. Various
pulp fibers can be utilized including, but not limited to,
thermomechanical pulp fibers, chemi-thermomechanical pulp fibers,
chemi-mechanical pulp fibers, refiner mechanical pulp fibers, stone
groundwood pulp fibers, peroxide mechanical pulp fibers and so
forth.
[0067] Suitable synthetic fibers can comprise fibers of one, or
more, of polyvinyl chloride, polyvinyl fluoride,
polytetrafluoroethylene, polyvinylidene chloride, polyacrylics such
as ORLON.RTM., polyvinyl acetate, Rayon.RTM., polyethylvinyl
acetate, non-soluble or soluble polyvinyl alcohol, polyolefins such
as polyethylene (e.g., PULPEX.RTM.) and polypropylene, polyamides
such as nylon, polyesters such as DACRON.RTM. or KODEL.RTM.,
polyurethanes, polystyrenes, and the like, including fibers
comprising polymers containing more than one monomer.
[0068] The substrate polymers suitable for the present invention
include polyolefins, polyesters, polyamides, polycarbonates,
polyurethanes, polyvinylchloride, polytetrafluoroethylene,
polystyrene, polyethylene terephathalate, biodegradable polymers
such as polylactic acid and copolymers and blends thereof. Suitable
polyolefins include polyethylene, e.g., high density polyethylene,
medium density polyethylene, low density polyethylene and linear
low density polyethylene; polypropylene, e.g., isotactic
polypropylene, syndiotactic polypropylene, blends of isotactic
polypropylene and atactic polypropylene, and blends thereof,
polybutylene, e.g., poly(1-butene) and poly(2-butene); polypentene,
e.g., poly(1-pentene) and poly(2-pentene);
poly(3-methyl-1-pentene); poly(4-methyl 1-pentene); and copolymers
and blends thereof. Suitable copolymers include random and block
copolymers prepared from two or more different unsaturated olefin
monomers, such as ethylene/propylene and ethylene/butylene
copolymers. Suitable polyamides include nylon 6, nylon 6/6, nylon
4/6, nylon 11, nylon 12, nylon 6/10, nylon 6/12, nylon 12/12,
copolymers of caprolactam and alkylene oxide diamine, and the like,
as well as blends and copolymers thereof. Suitable polyesters
include polyethylene terephthalate, polytrimethylene terephthalate,
polybutylene terephthalate, polytetramethylene terephthalate,
polycyclohexylene-1,4-dimethylene terephthalate, and isophthalate
copolymers thereof, as well as blends thereof.
[0069] Many other polyolefins are commercially available and
generally can be used in the present invention. Suitable
polyolefins are polypropylene and polyethylene. Many polyolefins
are available for fiber production, for example polyethylenes such
as Dow Chemical's ASPUN 6811A linear low-density polyethylene, 2553
LLDPE and 25355 and 12350 high-density polyethylene are such
suitable polymers. The polyethylenes have melt flow rates in g/10
min. at 190.degree. F. and a load of 2.16 kg, of about 26, 40, 25
and 12, respectively. Fiber forming polypropylenes include Exxon
Chemical Company's ESCORENE PD3445 polypropylene.
[0070] Examples of polyamides and their methods of synthesis may be
found in "Polymer Resins" by Don E. Floyd (Library of Congress
Catalog number 66-20811, Reinhold Publishing, N.Y., 1966).
Particularly commercially useful polyamides are nylon 6, nylon-6,6,
nylon-11 and nylon-12. These polyamides are available from a number
of sources such as Custom Resins, Nyltech, among others. In
addition, a compatible tackifying resin may be added to the
extrudable compositions described above to provide tackified
materials that autogenously bond or which require heat for bonding.
Any tackifier resin can be used which is compatible with the
polymers and can withstand the high processing (e.g., extrusion)
temperatures. If the polymer is blended with processing aids such
as, for example, polyolefins or extending oils, the tackifier resin
should also be compatible with those processing aids. Generally,
hydrogenated hydrocarbon resins are preferred tackifying resins,
because of their better temperature stability. REGALREZ.RTM. and
ARKON.RTM. P series tackifiers are examples of hydrogenated
hydrocarbon resins. ZONATAC.RTM. 501 lite is an example of a
terpene hydrocarbon. REGALREZ.RTM. hydrocarbon resins are available
from Hercules Incorporated. ARKON.RTM. series resins are available
from Arakawa Chemical (USA) Incorporated. The tackifying resins
such as disclosed in U.S. Pat. No. 4,787,699, hereby incorporated
by reference, are suitable. Other tackifying resins that are
compatible with the other components of the composition and can
withstand the high processing temperatures, can also be used.
[0071] Suitable thermoplastic fibers can be made from a single
polymer (monocomponent fibers), or can be made from more than one
polymer (e.g., bicomponent or multicomponent fibers).
Multicomponent fibers are described in U.S. Pat. App. 2003/0106568
to Keck and Arnold. Bicomponent fibers are described in U.S. Pat.
No. 6,613,704 to Arnold and Myers and references therein.
Multicomponent fibers of a wide range of denier or dtex are
described in U.S. Pat. App. 2002/0106478 to Hayase et. al. The
"bicomponent fibers" may be thermoplastic fibers that comprise a
core fiber made from one polymer that is encased within a
thermoplastic sheath made from a different polymer. The polymer
comprising the sheath often melts at a different, typically lower,
temperature than the polymer comprising the core. As a result,
these bicomponent fibers provide thermal bonding due to melting of
the sheath polymer, while retaining the desirable strength
characteristics of the core polymer.
[0072] Suitable bicomponent fibers for use in the present invention
can include sheath/core fibers having the following polymer
combinations: polyethylene/polypropylene, polyethylvinyl acetate/
polypropylene, polyethylene/ polyester, polypropylene/ polyester,
copolyester/ polyester, and the like. Particularly suitable
bicomponent thermoplastic fibers for use herein are those having a
polypropylene or polyester core, and a lower melting copolyester,
polyethylvinyl acetate or polyethylene sheath (e.g., those
available from Danaklon a/s, Chisso Corp., and CELBOND.RTM.,
available from Hercules). These bicomponent fibers can be
concentric or eccentric. As used herein, the terms "concentric" and
"eccentric" refer to whether the sheath has a thickness that is
even, or uneven, through the cross-sectional area of the
bicomponent fiber. Eccentric bicomponent fibers can be desirable in
providing more compressive strength at lower fiber thicknesses.
[0073] In suitable embodiments, it is desirable that the particular
polymers used for the different components of the fibers in the
practice of the invention have melting points different from one
another. This is important not only in producing crimped fibers but
also when through-air bonding is used as the bonding technique,
wherein the lower melting polymer bonds the fibers together to form
the fabric or web. It is desirable that the lower melting point
polymers make up at least a portion of the outer region of the
fibers. More particularly, the lower melting component should be
located in an outer portion of the fiber so that it comes in
contact with other fibers. For example, in a sheath/core fiber
configuration, the lower melting point polymer component should be
located in the sheath portion. In a side-by-side configuration, the
lower melting point polymer will inherently be located on an outer
portion of the fiber. Multicomponent conjugate fibers that contain
two or more component polymers, and more particularly suitable
fibers are multicomponent conjugate fibers containing polymers of
different melting points. Suitably, the melting point difference
between the highest melting polymer and the lowest melting polymer
of the conjugate fibers should be at least about 5.degree. C., or
about 30.degree. C., so that the lowest melting polymer can be
melted without affecting the chemical and physical integrities of
the highest melting polymer.
[0074] The proportion of higher and lower melting polymers in the
multicomponent, multilobal fibers can range between about 10-90% by
weight higher melting polymer and 10-90% lower melting polymer. In
practice, only so much lower melting polymer is needed as will
facilitate bonding between the fibers. Thus, a suitable fiber
composition may contain about 40-80% by weight higher melting
polymer and about 20-60% by weight lower melting polymer, desirably
about 50-75% by weight higher melting polymer and about 25-50% by
weight lower melting polymer. In one embodiment, a first polymer,
which is the lower melting point polymer, is polyethylene and the
higher melting point polymer is polypropylene.
[0075] The substrate can comprise solely naturally occurring
fibers, solely synthetic fibers, or any compatible combination of
naturally occurring and synthetic fibers. The fibers useful herein
can be hydrophilic, hydrophobic or can be a combination of both
hydrophilic and hydrophobic fibers. As indicated above, the
particular selection of hydrophilic or hydrophobic fibers depends
upon the other materials included in the absorbent (and to some
degree) the scrubbing layer described hereinafter. Suitable
hydrophilic fibers for use in the present invention include
cellulosic fibers, modified cellulosic fibers, rayon, cotton, and
polyester fibers, such as hydrophilic nylon (HYDROFIL.RTM.).
Suitable hydrophilic fibers can also be obtained by hydrophilizing
hydrophobic fibers, such as surfactant-treated or silica-treated
thermoplastic fibers derived from, for example, polyolefins such as
polyethylene or polypropylene, polyacrylics, polyamides,
polystyrenes, polyurethanes and the like.
[0076] Another type of hydrophilic fiber for use in the present
invention is chemically stiffened cellulosic fibers. As used
herein, the term "chemically stiffened cellulosic fibers" means
cellulosic fibers that have been stiffened by chemical means to
increase the stiffness of the fibers under both dry and aqueous
conditions. Such means can include the addition of a chemical
stiffening agent that, for example, coats and/or impregnates the
fibers. Such means can also include the stiffening of the fibers by
altering the chemical structure, e.g., by crosslinking polymer
chains.
[0077] Fibers can optionally be combined with a thermoplastic
material. Upon melting, at least a portion of this thermoplastic
material migrates to the intersections of the fibers, typically due
to interfiber capillary gradients. These intersections become bond
sites for the thermoplastic material. When cooled, the
thermoplastic materials at these intersections solidify to form the
bond sites that hold the matrix or web of fibers together in each
of the respective layers. This can be beneficial in providing
additional overall integrity to the cleaning substrate. Amongst its
various effects, bonding at the fiber intersections increases the
overall compressive modulus and strength of the resulting thermally
bonded member. In the case of the chemically stiffened cellulosic
fibers, the melting and migration of the thermoplastic material
also has the effect of increasing the average pore size of the
resultant web, while maintaining the density and basis weight of
the web as originally formed. This can improve the fluid
acquisition properties of the thermally bonded web upon initial
exposure to fluid, due to improved fluid permeability, and upon
subsequent exposure, due to the combined ability of the stiffened
fibers to retain their stiffness upon wetting and the ability of
the thermoplastic material to remain bonded at the fiber
intersections upon wetting and upon wet compression. In net,
thermally bonded webs of stiffened fibers retain their original
overall volume, but with the volumetric regions previously occupied
by the thermoplastic material becoming open to thus increase the
average interfiber capillary pore size.
[0078] Thermoplastic materials useful in the present invention can
be in any of a variety of forms including particulates, fibers, or
combinations of particulates and fibers. Thermoplastic fibers are a
particularly preferred form because of their ability to form
numerous interfiber bond sites. Suitable thermoplastic materials
can be made from any thermoplastic polymer that can be melted at
temperatures that will not extensively damage the fibers that
comprise the primary web or matrix of each layer. Suitably, the
melting point of this thermoplastic material will be less than
about 190.degree. C., or between about 75.degree. C. and about
175.degree. C. In any event, the melting point of this
thermoplastic material should be no lower than the temperature at
which the thermally bonded structures are likely to be stored. The
melting point of the thermoplastic material is typically no lower
than about 50.degree. C.
[0079] The surface of the hydrophobic thermoplastic fiber can be
rendered hydrophilic by treatment with a surfactant, such as a
nonionic or anionic surfactant, e.g., by spraying the fiber with a
surfactant, by dipping the fiber into a surfactant or by including
the surfactant as part of the polymer melt in producing the
thermoplastic fiber. Upon melting and resolidification, the
surfactant will tend to remain at the surfaces of the thermoplastic
fiber. Suitable surfactants include nonionic surfactants such as
Brij.RTM. 76 manufactured by ICI Americas, Inc. of Wilmington,
Del., and various surfactants sold under the Pegosperse.RTM.
trademark by Glyco Chemical, Inc. of Greenwich, Conn. Besides
nonionic surfactants, anionic surfactants can also be used. These
surfactants can be applied to the thermoplastic fibers at levels
of, for example, from about 0.2 to about 1 g per square centimeter
of thermoplastic fiber.
[0080] In one embodiment, the cleaning substrate has at least two
regions where the regions are distinguished by basis weight.
Briefly, the measurement is achieved photographically, by
differentiating dark (low basis weight) and light (high basis)
network regions. In particular, the cleaning substrate comprises
one or more low basis weight regions, wherein the low basis
region(s) have a basis weight that is not more than about 80% of
the basis weight of the high basis weight regions. In one aspect,
the first region is relatively high basis weight and comprises an
essentially continuous network. The second region comprises a
plurality of mutually discrete regions of relatively low basis
weight and which are circumscribed by the high basis weight first
region. In particular, a cleaning substrate may comprise a
continuous region having a basis weight of from about 30 to about
120 grams per square meter and a plurality of discontinuous regions
circumscribed by the high basis weight region, wherein the
discontinuous regions are disposed in a random, repeating pattern
and having a basis weight of not more than about 80% of the basis
weight of the continuous region.
[0081] In one embodiment, the cleaning substrate will have, in
addition to regions which differ with regard to basis weight,
substantial macroscopic three-dimensionality. The term "macroscopic
three-dimensionality", when used to describe three dimensional
cleaning substrates means a three-dimensional pattern is readily
visible to the naked eye when the perpendicular distance between
the viewer's eye and the plane of the substrate is about 12 inches.
In other words, the three dimensional structures of the
pre-moistened substrates of the present invention are cleaning
substrates that are non-planar, in that one or both surfaces of the
substrates exist in multiple planes. By way of contrast, the term
"planar", refers to substrates having fine-scale surface
aberrations on one or both sides, the surface aberrations not being
readily visible to the naked eye when the perpendicular distance
between the viewer's eye and the plane of the sheet is about 12
inches. In other words, on a macro scale the observer will not
observe that one or both surfaces of the substrate will exist in
multiple planes so as to be three-dimensional.
[0082] Briefly, macroscopic three-dimensionality is described in
terms of average height differential, which is defined as the
average distance between adjacent peaks and valleys of a given
surface of a substrate, as well as the average peak-to-peak
distance, which is the average distance between adjacent peaks of a
given surface. Macroscopic three dimensionality is also described
in terms of surface topography index of the outward surface of a
cleaning substrate; surface topography index is the ratio obtained
by dividing the average height differential of a surface by the
average peak-to-peak distance of that surface. In one embodiment, a
macroscopically three-dimensional cleaning substrate has a first
outward surface and a second outward surface wherein at least one
of the outward surfaces has a peak to peak distance of at least
about 1 mm and a surface topography index from about 0.01 mm to
about 10 mm. The macroscopically three-dimensional structures of
the substrates of the present invention optionally comprise a
scrim, which when heated and the cooled, contract so as to provide
further macroscopic three-dimensional structure.
[0083] In another embodiment, the substrate can comprise a laminate
of two outer hydroentangled webs, such as nonwoven webs of
polyester, rayon fibers or blends thereof having a basis weight of
about 10 to about 60 grams per square meter, joined to an inner
constraining layer, which can be in the form of net like scrim
material which contracts upon heating to provide surface texture in
the outer layers.
[0084] Chemical bonding utilizes a solvent or adhesive, and U.S.
Pat. No. 3,575,749 to Kroyer discloses bonding the fibrous layer
with a latex binder, which may be applied to one or both sides of
the web. Binders may comprise liquid emulsions, latex binders,
liquid adhesives, chemical bonding agents, and mixtures thereof.
The binder composition can be made using a latex adhesive
commercially available as Rovene 5550 (49 percent solids styrene
butadiene) available from Mallard Creek Polymers of Charlotte, N.C.
Other suitable binders are available from National Starch and
Chemical, including DUR-O-SET 25-149A (Tg=+9.degree. C.), NACRYLIC
25-012A (Tg=-34.degree. C.), NACRYLIC 25-4401 (Tg=-23.degree. C.),
NACRYLIC ABX-30-25331A, RESYN 1072 (Tg=+37.degree. C.), RESYN 1601,
X-LINK25-033A, DUR-O-SET C310, DUR-O-SET ELITE ULTRA, (vinylacetate
hompolymers and copolymers), STRUCTURECOTE 1887 (modified starch),
NATIONAL 77-1864 (Tg=+100.degree. C.)(modified starch), TYLAC
NW-4036-51-9 (styrene-butadiene terpolymer), and from Air Products
Polymers, including Flexbond AN214 (Tg=+30.degree. C.)(vinylacetate
copolymer). A latex emulsion or solution, typically in an aqueous
medium, is applied to one or both surfaces of the web to provide a
latex coating which partially impregnates the web, and upon curing
stabilizes the structure. The latex may be applied to the web by
any suitable means such as spraying, brushing, flooding, rolling,
and the like. The amount of latex applied and the degree of
penetration of the latex are controlled so as to avoid impairing
the effective absorbency.
[0085] Examples of suitable nonwoven water insoluble substrates
include, 100% cellulose Wadding Grade 1804 from Little Rapids
Corporation, 100% polypropylene needlepunch material NB 701-2.8-W/R
from American Non-wovens Corporation, and a blend of cellulosic and
synthetic fibres-Hydraspun 8579 from Ahlstrom Fibre Composites.
Another useful substrate is manufactured by Jacob Holm-Lidro Rough.
It is a composition material comprising a 65/35 viscose
rayon/polyester hydroentangled spunlace layer with a
hydroenlongated bonded polyeser scribbly layer. Still another
useful substrate is manufactured by Texel "TI". It is a composite
material manufactured from a layer of coarse fiber 100%
polypropylene needlepunch, an absorbent cellulose core and a fine
fiber polyester layer needlepunched together. The polypropylene
layer can range from 1.5 to 3.5 oz/sq. yd. The cellulose core is a
creped paper layer ranging from 0.5 to 2 oz./sq. yd. The fine fiber
polyester layer can range from 0.5 to 2 oz./sq. yd. Still another
composite material manufactured by Texcel from a layer of coarse
fiber 100% polypropylene needlepunch layer, an absorbent cellulose
core and a fine fiber polyester layer needlepunched together. The
polypropylene layer can range from 1.5 to 3.5 oz/sq. yd. The
cellulose core is a creped paper layer ranging from 0.5 to 2 oz/sq.
yd. The fine fiber polyester layer can range from 0.5 to 2 oz/sq.
yd. The polypropylene layer is flame treated to further increase
the level of abrasivity. The temperature of the flame and the
length of time the material is exposed can be varied to create
different levels of surface roughness.
[0086] Ahlstrom manufactures a hydroentangled nonwoven created from
a blend of cellulosic and polyester and/or polypropylene fibers
with an abrasive side. The basis weight can range from 1.2 to 6
ounces per square yard. A composite dual textured material
manufactured by Kimberly Clark comprises a coarse meltblown
polypropylene, polyethylene, or polyester and high loft spunbond
polyester. The two materials can be laminated together using
chemical adhesives or by coprocessing the two layers. The coarse
meltblown layer can range from 1 to 3 ounces per square yard while
the highloft spunbond layer can range from 1 to 3 ounces per square
yard. Another example of a composite is a dual textured material
composed of coarse meltblown polypropylene, polyethylene, or
polyester and polyester/cellulose coform. The two materials can be
laminated together using chemical adhesives or by coprocessing the
two layers. The coarse meltblown layer can range from 1 to 3 ounces
per square yard. The coform layer can range in composition from 30%
cellulose and 70% polyester to 70% cellulose and 30% polyester and
the basis weight can range from 1.5 to 4.5 ounces per square
yard.
[0087] The product of the present invention comprising mutliple
layers may be ultrasonically bonded after applying the coating of
one or more of the layers. Alternatively, layers may be bonded
together by needlepunch, thermal bonding, chemical bonding, or
sonic bonding prior to applying the coating and/or
impregnation.
[0088] A multilayer laminate may be an embodiment wherein some of
the layers are spunbond and some meltblown such as a
spunbond/meltblown/spunbond (SMS) laminate as disclosed in U.S.
Pat. No. 4,041,203 to Brock et al. and U.S. Pat. No. 5,169,706 to
Collier, et al., each hereby incorporated by reference. The SMS
laminate may be made by sequentially depositing onto a moving
conveyor belt or forming wire first a spunbond web layer, then a
meltblown web layer and last another spunbond layer and then
bonding the laminate in a manner described above. Alternatively,
the three web layers may be made individually, collected in rolls
and combined in a separate bonding step.
[0089] In one exemplary process, the substrate comprises a laminate
formed by two plies a and b. Both plies a and b are transported in
the machine direction. Optionally a glue may be applied to one of
the plies a or b by a glue applicator, so that the plies a, b can
be consequently joined together. Alternatively, the functional
additive may be used to join the plies together, and without using
an additional adhesive. During the process, the functional additive
is deposited onto the ply a by a functional additive applicator.
Then, the plies a, b are joined together at a combining roll such
that the functional additive or adhesive is interposed between the
two plies a, b. In a multilayer substrate, the generation of a
laminate structure can also take place when a film is bonded to
another nonwoven layer. The laminate may further be perforated by a
perforator, slit into individual sheets by slitters, and wound into
the roll, as well known by those skilled in the art. Single layer
substrates may also be be perforated by a perforator, slit into
individual sheets by slitters, and wound into the roll.
[0090] U.S. Pat. No. 6,270,878 to Wegele describes the processing
of nonwoven sheets and rolls. Depending upon the desired
application, the substrates may be provided as discrete units or
may be joined in seriatim by perforations, etc. The substrates may
be individually dispensed, such as is commonly done for facial
tissues. If individual dispensing is desired, the substrates may be
provided in either a reach-in or pop up dispenser, as disclosed
U.S. Pat. No. 4,623,074 to Dearwester; U.S. Pat. No. 5,520,308 to
Berg. Jr. et al. and U.S. Pat. No. 5,516,001 issued to Muckenfuhs
et al., the disclosures of which are incorporated herein by
reference. Alternatively, the substrates may be core-wound, as
disclosed in U.S. Pat. No. 5,318,235 to Sato, the disclosure of
which is incorporated herein by reference. These substrates are
pulled from the center of a hollow coreless roll that has
perforated sheets. These containers generally have a snap top lid
that is opened to expose a piece of the substrates that can then be
pulled to remove the desired amount of substrates. If desired, the
substrates may be lightly compressed for packaging. Such packaging
may be accomplished as disclosed U.S. Pat. No. 5,664,897 to Young
et al., the disclosure of which is incorporated herein by
reference.
Additional Substrate Components
[0091] The substrate may also contain superabsorbent materials. A
wide variety of high absorbency materials (also known as
superabsorbent materials) are known to those skilled in the art.
See, for example, U.S. Pat. No. 4,076,663 issued Feb. 28, 1978 to
Masuda et al, U.S. Pat. No. 4,286,082 issued Aug. 25, 1981 to
Tsubakimoto et al., U.S. Pat. No. 4,062,817 issued Dec. 13, 1977 to
Westerman, and U.S. Pat. No. 4,340,706 issued Jul. 20, 1982 to
Obayashi et al. The absorbent capacity of such high-absorbency
materials is generally many times greater than the absorbent
capacity of fibrous materials. For example, a fibrous matrix of
wood pulp fluff can absorb about 7-9 grams of a liquid, (such as
0.9 weight percent saline) per gram of wood pulp fluff, while the
high-absorbency materials can absorb at least about 15, preferably
at least about 20, and often at least about 25 grams of liquid,
such as 0.9 weight percent saline, per gram of the high-absorbency
material. U.S. Pat. No. 5,601,542, issued to Melius et al.,
discloses an absorbent article in which superabsorbent material is
contained in layers of discrete pouches. Alternately, the
superabsorbent material may be within one layer or dispersed
throughout the substrate.
[0092] The superabsorbent materials can be natural, synthetic, and
modified natural polymers and materials. In addition, the
superabsorbent materials can be inorganic materials, such as silica
gel, or organic compounds such as cross-linked polymers. The term
"cross-linked" refers to any means for effectively rendering
normally water-soluble materials substantially water insoluble but
swellable. Such means can include, for example, physical
entanglement, crystalline domains, covalent bonds, ionic complexes
and associations, hydrophilic associations, such as hydrogen
bonding, and hydrophobic associations of Van der Waals forces.
[0093] Examples of synthetic superabsorbent material polymers
include the alkali metal and ammonium salts of poly(acrylic acid)
and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers),
maleic anhydride copolymers with vinyl ethers and alpha-olefins,
poly(vinyl pyrrolidone), poly(vinylmorpholinone), poly(vinyl
alcohol), and mixtures and copolymers thereof. Further
superabsorbent materials include natural and modified natural
polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic
acid grafted starch, methyl cellulose, chitosan, carboxymethyl
cellulose, hydroxypropyl cellulose, and the natural gums, such as
alginates, xanthan gum, locust bean gum and the like. Mixtures of
natural and wholly or partially synthetic superabsorbent polymers
can also be useful in the present invention. Other suitable
absorbent gelling materials are disclosed by Assarsson et al. in
U.S. Pat. No. 3,901,236 issued Aug. 26, 1975. Processes for
preparing synthetic absorbent gelling polymers are disclosed in
U.S. Pat. No. 4,076,663 issued Feb. 28, 1978 to Masuda et al. and
U.S. Pat. No. 4,286,082 issued Aug. 25, 1981 to Tsubakimoto et
al.
[0094] Superabsorbents may be particulate or fibrous, and are
preferably particulate. Superabsorbents are generally available in
particle sizes ranging from about 20 to about 1000 microns.
Preferred particle sizes range from 100 to 1000 microns. Examples
of commercially available particulate superabsorbents include
SANWET.RTM. IM 3900 and SANWET.RTM. IM-5000P, available from
Hoescht Celanese located in Portsmouth, Va., DRYTECH.RTM. 2035LD
available from Dow Chemical Co. located in Midland, Mich., and
FAVOR.RTM. 880 available from Stockhausen, located in Sweden.
FAVOR.RTM. 880 is presently preferred because of its high gel
strength. An example of a fibrous superabsorbent is OASIS.RTM. 101,
available from Technical Absorbents, located in Grimsby, United
Kingdom.
Tensile Strength
[0095] Sufficient seal strength between laminated layers is
important to prevent the layers from peeling off one another. The
seal strength is measured using a tensile tester. The tensile
tester is a device constructed in such a way that a gradually
increasing load is smoothly applied to a defined sample portion
until the sample portion breaks. The tensile at the point of
breakage (at which time the sample breaks) is frequently called
"peak" tensile, or just "peak". The suitable instrument used for
the measurement is Instron 5564, which may be equipped with either
digital readout or strip chart data display for load and
elongation. The following procedure is conducted under standard
laboratory conditions at 23.degree. C. (73.degree. F.) and 50%
relative humidity for a minimum of 2.0 hours. (1) Cut a sample into
a strip having 1 inch by 5 inches size. At least three strips
should be prepared for the measurement. (2) Put the sample strip in
the instrument. The way to set the sample strip is to insert the
sample strip into the top clamp of the instrument first, and then
to clamp the sample strip into the bottom clamp with enough tension
to eliminate any slack of the sample strip. (3) Strain the sample
strip at 5 inches/minute until breaking it. (4) Read the peak
tensile value. (5) Repeat the above procedures (1) to (4) for the
other sample strips. (6) Calculate the average tensile as follows:
Average Tensile (g/in)=Sum of the peak loads for samples tested
divided by the number of test strips tested.
[0096] The average tensile value for use herein is the average
tensile of the three samples. Calculate and report to the nearest
whole unit. The seal strength may be at least 120 g/in, preferably
300 g/in, and more preferably 500 g/in to prevent tearing during
use.
Cleaning or Treatment Composition
[0097] The substrate may contain a cleaning or treatment
composition. The substrate may not contain a cleaning or treatment
composition. The treatment composition may comprise surfactants,
solvents, additional adjuncts, water or any combination thereof.
The treatment composition may be added prior to post-treatment or
in a post-treatment operation, such as on the conversion line or in
a consumer container.
Surfactants
[0098] The cleaning composition may contain one or more surfactants
selected from anionic, nonionic, cationic, ampholytic, amphoteric
and zwitterionic surfactants and mixtures thereof. A typical
listing of anionic, nonionic, ampholytic, and zwitterionic classes,
and species of these surfactants, is given in U.S. Pat. No.
3,929,678 to Laughlin and Heuring. A list of suitable cationic
surfactants is given in U.S. Pat. No. 4,259,217 to Murphy. Where
present, ampholytic, amphotenic and zwitteronic surfactants are
generally used in combination with one or more anionic and/or
nonionic surfactants.
Solvent
[0099] Suitable organic solvents include, but are not limited to,
C1-6 alkanols, C1-6 diols, C.sub.1-10 alkyl ethers of alkylene
glycols, C.sub.3-24 alkylene glycol ethers, polyalkylene glycols,
short chain carboxylic acids, short chain esters, isoparafinic
hydrocarbons, mineral spirits, alkylaromatics, terpenes, terpene
derivatives, terpenoids, terpenoid derivatives, formaldehyde, and
pyrrolidones. Alkanols include, but are not limited to, methanol,
ethanol, n-propanol, isopropanol, butanol, pentanol, and hexanol,
and isomers thereof Diols include, but are not limited to,
methylene, ethylene, propylene and butylene glycols. Alkylene
glycol ethers include, but are not limited to, ethylene glycol
monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol
monohexyl ether, diethylene glycol monopropyl ether, diethylene
glycol monobutyl ether, diethylene glycol monohexyl ether,
propylene glycol methyl ether, propylene glycol ethyl ether,
propylene glycol n-propyl ether, propylene glycol monobutyl ether,
propylene glycol t-butyl ether, di- or tri-polypropylene glycol
methyl or ethyl or propyl or butyl ether, acetate and propionate
esters of glycol ethers. Short chain carboxylic acids include, but
are not limited to, acetic acid, glycolic acid, lactic acid and
propionic acid. Short chain esters include, but are not limited to,
glycol acetate, and cyclic or linear volatile methylsiloxanes.
Water insoluble solvents such as isoparafinic hydrocarbons, mineral
spirits, alkylaromatics, terpenoids, terpenoid derivatives,
terpenes, and terpenes derivatives can be mixed with a
water-soluble solvent when employed. The solvents are preferably
present at a level of from 0.001% to 10%, more preferably from
0.01% to 10%, most preferably from 1% to 4% by weight.
Additional Adjuncts
[0100] The cleaning compositions optionally contain one or more of
the following adjuncts: stain and soil repellants, lubricants, odor
control agents, perfumes, fragrances and fragrance release agents,
and bleaching agents. Other adjuncts include, but are not limited
to, acids, electrolytes, dyes and/or colorants, solubilizing
materials, stabilizers, thickeners, defoamers, hydrotropes, cloud
point modifiers, preservatives, and other polymers. The
solubilizing materials, when used, include, but are not limited to,
hydrotropes (e.g. water soluble salts of low molecular weight
organic acids such as the sodium and/or potassium salts of toluene,
cumene, and xylene sulfonic acid). The acids, when used, include,
but are not limited to, organic hydroxy acids, citric acids, keto
acid, and the like. Electrolytes, when used, include, calcium,
sodium and potassium chloride. Thickeners, when used, include, but
are not limited to, polyacrylic acid, xanthan gum, calcium
carbonate, aluminum oxide, alginates, guar gum, methyl, ethyl,
clays, and/or propyl hydroxycelluloses. Defoamers, when used,
include, but are not limited to, silicones, aminosilicones,
silicone blends, and/or silicone/ hydrocarbon blends. Bleaching
agents, when used, include, but are not limited to, peracids,
hypohalite sources, hydrogen peroxide, and/or sources of hydrogen
peroxide.
[0101] An effective amount on antimicrobial active may be needed on
the substrate depending on the size of the surface to be cleaned
and the level of antimicrobial effectiveness desired. Antimicrobial
agents include quaternary ammonium compounds and phenolics.
Non-limiting examples of these quaternary compounds include
benzalkonium chlorides and/or substituted benzalkonium chlorides,
di(C.sub.6-C.sub.14)alkyl di short chain (C.sub.1-4 alkyl and/or
hydroxyalkl) quaternaryammonium salts, N-(3-chloroallyl) hexaminium
chlorides, benzethonium chloride, methylbenzethonium chloride, and
cetylpyridinium chloride. Other quaternary compounds include the
group consisting of dialkyldimethyl ammonium chlorides, alkyl
dimethylbenzylammonium chlorides, dialkylmethylbenzylammonium
chlorides, biguanides, including polyhexamethylene biguanide and
mixtures thereof. Additional antimicrobial agents include metallic
materials, which bind to cellular proteins of microorganisms and
are toxic to the microorganisms are suitable. The metallic material
can be a metal, metal oxide, metal salt, metal complex, metal alloy
or mixture thereof. Examples of such metals include, silver, zinc,
cadmium, lead, mercury, antimony, gold, aluminum, copper, platinum
and palladium, their salts, oxides, complexes, and alloys, and
mixtures thereof. Additional antimicrobial agents include peroxides
and hypohalite compounds and similar compounds that may be provided
by a variety of sources, including compounds that lead to the
formation of positive halide ions and/or hypohalite ions, as well
as bleaches that are organic based sources of halides, such as
chloroisocyanurates, haloamines, haloimines, haloimides and
haloamides, or mixtures thereof.
[0102] The cleaning composition may include a builder or buffer,
which increase the effectiveness of the surfactant. A variety of
builders or buffers can be used and they include, but are not
limited to, phosphate-silicate compounds, zeolites, alkali metal,
ammonium and substituted ammonium polyacetates, trialkali salts of
nitrilotriacetic acid, carboxylates, polycarboxylates, carbonates,
bicarbonates, polyphosphates, aminopolycarboxylates,
polyhydroxysulfonates, and starch derivatives. Builders or buffers
can also include polyacetates and polycarboxylates. Buffering and
pH adjusting agents include organic acids, mineral acids, alkali
metal and alkaline earth salts of silicate, metasilicate,
polysilicate, borate, hydroxide, carbonate, carbamate, phosphate,
polyphosphate, pyrophosphates, triphosphates, tetraphosphates,
ammonia, hydroxide, monoethanolamine, monopropanolamine,
diethanolamine, dipropanolamine, triethanolamine, and
2-amino-2methylpropanol. When employed, the builder, buffer, or pH
adjusting agent comprises at least about 0.001% and typically about
0.01-5% of the cleaning composition. Preferably, the builder or
buffer content is about 0.01-2%.
Water
[0103] Since the composition is an aqueous composition, water can
be, along with the solvent, a predominant ingredient. The water can
be present at a level of less than 99.9%, or less than about 99%,
or less than about 98%. Deionized water is suitable. Where the
cleaning composition is concentrated, the water may be present in
the composition at a concentration of less than about 85 wt. %.
Applications
[0104] The present invention is suitable for a wide array of dry
and wet wipe applications. Surface cleaning wipes work by various
means, including but not limited to mechanical abrasive action to
loosen soil from a surface, solublization of soil from the lotion
in the wet wipe, and collection and entrapment of soil into the
structure of the wet wipe. A relatively high friction surface can
improve cleaning from surfaces. Wipes can be produced as
pre-moistened wet wipes or packaged as dry wipes where the consumer
adds a liquid such as lotion or water.
[0105] The substrate can be used for cleaning, disinfectancy, or
sanitization on inanimate, household surfaces, including floors,
counter tops, furniture, windows, walls, and automobiles. Other
surfaces include stainless steel, chrome, and shower enclosures.
The substrate can be packaged individually or together in
canisters, tubs, etc. The substrate can be used with the hand, or
as part of a cleaning implement attached to a tool or motorized
tool, such as one having a handle. Examples of tools using a
substrate include U.S. Pat. No. 6,611,986 to Seals, WO00/71012 to
Belt et al., U.S. Pat. App. 2002/0129835 to Pieroni and Foley, and
WO00/27271 to Policicchio et al.
Cleaning Implement
[0106] In an embodiment of the invention, the substrate is attached
to a cleaning implement. In an embodiment of the invention, the
cleaning implement comprises the tool assembly disclosed in U.S.
Pat. App. 2005/0066465, entitled "Cleaning Tool with Gripping
Assembly for a Disposable Scrubbing Head". Examples of suitable
cleaning implements are found in US2003/0070246 to Cavalheiro; U.S.
Pat. No. 4,455,705 to Graham; U.S. Pat. No. 5,003,659 to Paepke;
U.S. Pat. No. 6,485,212 to Bomgaars et al.; U.S. Pat. No. 6,290,781
to Brouillet, Jr.; U.S. Pat. No. 5,862,565 to Lundstedt; U.S. Pat.
No. 5,419,015 to Garcia; U.S. Pat. No. 5,140,717 to Castagliola;
U.S. Pat. No. 6,611,986 to Seals; US2002/0007527 to Hart; and U.S.
Pat. No. 6,094,771 to Egolf et al. The cleaning implement may have
a hook, hole, magnetic means, canister or other means to allow the
cleaning implement to be conveniently stored when not in use.
Cleaning Substrate Attachment
[0107] The cleaning implement holding the removable cleaning
substrate may have a cleaning head with an attachment means or the
attachment means may be an integral part of the handle of the
cleaning implement or may be removably attached to the end of the
handle. The cleaning substrate may be attached by a friction fit
means, by a clamping means, by a threaded screw means, by hook and
loop attachment or by any other suitable attachment means. The
cleaning substrate may have a rigid or flexible plastic or metal
fitment for attachment to the cleaning implement or the cleaning
substrate may be directly attached to the cleaning implement. Any
of these substrates may be water-insoluble, water-dispersible, or
water-soluble.
Consumer Containers
[0108] The term "container", refers to, but is not limited to,
packets containing one or more individual substrates and bulk
dispensers, such as canisters, tubs and jars, which dispense one
substrate at a time. The substrates can be maintained over time in
a sealable container such as, for example, within a bucket with an
attachable lid, sealable plastic pouches or bags, canisters, jars,
tubs and so forth. Exemplary resealable containers and dispensers
include, but are not limited to, those described in U.S. Pat. No.
4,171,047 to Doyle et al., U.S. Pat. No. 4,353,480 to McFadyen,
U.S. Pat. No. 4,778,048 to Kaspar et al., U.S. Pat. No. 4,741,944
to Jackson et al., U.S. Pat. No. 5,595,786 to McBride et al., U.S.
Pat. App. 2001/0020632 to De Oliveira et al., U.S. Pat. App.
2001/0055609 to Shantz et al., U.S. Pat. App. 2002/0068142 to
Baroni et al., U.S. Pat. App. 2004/0007113 to Morrisey-Hawkins; the
entire contents of each of the aforesaid references are
incorporated herein by reference. There are two basic types of
containers for such wet wipes namely, multiwipe containers and
single wipe packages. In typical multiwipe containers, a flexible
or rigid moisture impervious container is utilised, the wipes being
folded and stacked in such an arrangement therein, so that a single
wipe is exposed to and removed by a consumer at one time. These
containers have a tub like configuration or a flexible rectangular
package, both of which are typically resealable after opening.
[0109] Wet wipes have been traditionally dispensed in sheet form
from a tub like container with a hinged lid on the top. The lid is
opened and individual or singularized sheets of the wipes are
removed. Another type of container that has been used for wet wipes
provides a roll of wipes in which the wipes are pulled from the top
of the container in a direction that is parallel to the axis of the
roll. These wipes are pulled from the center of a hollow coreless
roll that has perforated sheets. These containers generally have a
snap top lid that is opened to expose a piece of the wipes that can
then be pulled to remove the desired amount of wipes. Once pulled
out the wipes can then be torn off, usually at a perforation, and
the lid closed. It is to be understood, however, that cored rolls
(hollow cores, solid cores and partially solid cores), hollow
coreless rolls, and stacks of sheets may also be used in the
dispenser system.
EXAMPLES
[0110] During conversion process, the nonwoven substrate is subject
to various operations to give it physical integrity, give it
suitable physical properties, and provide it in a useful form. For
example, the outer cover of fibers can be joined by bonding to form
a coherent web structure. Suitable bonding techniques include, but
are not limited to, chemical bonding, thermobonding, and processes
such as point calendering, hydroentangling, and needling. The
substrate may contain two to more layers laminated together at bond
sites. In one embodiment, the laminated substrate may be further
processed to form apertures in the whole laminate substrate (or
portions thereof) by extending portions of the substrate in a
direction orthogonal to the axis of bond sites. One method for
forming apertures across the substrate is to pass the substrate
through a nip formed by incremental stretching system employing
opposed pressure applicators having three-dimensional surfaces,
which at least to a degree are complementary to one another.
Stretching of the laminate substrate may be accomplished by other
methods known in the art, including tentoring, or even by hand.
[0111] There may optionally be a device for perforating the
substrate. The perforation may be accomplished by a pair of
rollers, wherein at least one of the rollers comprises a series of
teeth or blades such that the impact of the rollers on the
substrate results in incisions in a line forming a perforation
line. The incisions within the perforation line may be spaced
regularly, they may be spaced randomly, or they may be spaced in a
controlled arrangement. The perforations are suitably in the cross
direction (CD) of the web; that is in the plane of the web
perpendicular to the direction of movement, or the machine
direction (MD). The perforation may be accomplished by methods
known to those skilled in the art. For example, a perforating
apparatus as described in U.S. Pat. No. 5,125,302, incorporated
herein by reference, may be used to perforate the substrate. The
perforating apparatus may contain a rotating perforation roll and a
stationary anvil bar. The perforation roll in this case has
multiple rows of blades along the CD of the roll, and these blades
protrude slightly from the face of the roll. The space between
these rows and the length of the blades dictates the perforation
length and spacing. The anvil bar is typically configured as a
helix, for example a double helix or single helix, such that it
contacts the perforation blades only at one or two positions at a
time. Thus, as the perforation roll rotates, the substrate becomes
perforated across the entire substrate. The substrate typically
wraps the rotating perforation roll. The perforating apparatus may
contain a rotating anvil roll with a stationary perforation blade.
Typically, multiple anvil bars are configured in a helix around the
anvil roll and engage the perforation blade. The substrate is
perforated in one location at any one time. The substrate does not
typically wrap either the anvil roll or the perforation blade.
Also, the anvil roll may be kept stationary and the perforation
blade may be rotated on a roll.
[0112] At the end of a typical conversion process the substate is
slit and/or wound. The winding apparatus may be any winding
apparatus known to those skilled in the art. The winding apparatus
may, for example, wind a substrate around a removable mandrel to
produce a coreless material (U.S. Pat. Nos. 5,387,284; 5,271,515;
5,271,137; 3,856,226). The winding apparatus may, for example, wind
a substrate around a tubular or cylindrical core (U.S. Pat. Nos.
6,129,304; 5,979,818; 5,368,252; 5,248,106; 5,137,225; 4,487,377).
The winding apparatus may, for example, be a coreless surface
winder, which can produce coreless rolls without the use of a
mandrel. (U.S. Pat. Nos. 5,839,680; 5,690,296; 5,603,467;
5,542,622; 5,538,199; 5,402,960; 4,856,725). The above applications
are incorporated herein by reference
[0113] The perforating and rewinding of a non-flat rollstock is
currently a complicated process. It is typically completed by
pulling the Z dimension out of the rollstock and using precise
tension control at the conversion operation point. An example would
be at the nip of the rotating knives in the case of perforation.
The Z dimension is then re-established by the relaxation of the
tension on the web and the re-establishing of the original
structure due to the previously locked in structure of the fiber
bonds that make up the rollstock. The precise tension control and
other required system elements and methods are expensive and not
always able to be coordinated with the characteristics of the web.
A process which avoids having to convert a high drape, flexible
nonwoven with a Z dimension to recover after releasing the
converting tension would be a significant contributor to machine
speed and efficiency. The bond pattern and the subsequent loft or Z
dimension details could be tailored for the specific consumer
application without regard to the converting line efficiencies. The
liquid absorptivity and its correlation to the shape of the
generated Z dimension could be developed to meet the current needs
of the consumer at point of use delivery and of the lotion loading
manufacturing process effectiveness.
[0114] In one embodiment, the process described herein would allow
the Z dimension to be created in the article after it is perforated
and/or rolled. In one embodiment, the process described herein
would allow the Z dimension to be created in the article after it
is slit into individual units (such as sheets, mitts, diapers) or
individual rolls. In one embodiment, final process could be
performed after it is placed in its consumer packaging, thus
eliminating the need for the complex tension control at the point
of conversion. For example, the use of particular bond point
patterns in conjunction with nonwoven fibers and webs with
dissimilar thermal expansion coefficients that are subjected to
heat after conversion could be used to form loft or Z dimension in
the web in its final package. In one embodiment, a nonwoven can be
formed from materials and bonded with reference points such that it
can be perforated, wound into a donut and placed into a canister as
a flat rollstock and then can be subjected to treatment, such as
heat, such that the thermal expansion rates of the dissimilar
components initiate the formation of stresses that force the web
and bond points to create a Z dimension (or thickness) in the
previously flat wound roll.
[0115] In one embodiment, the bond point pattern and the related
dissimilarity in the shrinking characteristics of either two
separate webs made up individually of fibers with different thermal
expansion and contraction characteristics or of an individual web
made up of fibers that are commingled in the web forming process
that have dissimilar thermal expansion and contraction
characteristics that when activated with heat after the web is
converted creates wrinkles and puffs that give the web its desired
Z dimension. The bond point pattern and the difference in thermal
expansion coefficients control the ultimate Z dimension. The amount
of heat applied to initiate the thermal contraction of one of the
web components and/or the thermal expansion of the other controls
the ultimate Z dimension. The magnitude of the difference in the
thermal expansion and contraction coefficients controls the
ultimate Z dimension. The heat can be applied prior to or after
loading of the lotion, and the heat can drive off the volatile
component of the active ingredient if the wipe is to be water
activated dry wipe application. The heat applied thus would have
two functions, to initiate the creation of the Z dimension, and to
create a dry wipe or wipe with different lotion properties. If a
wet wipe is desired, then the heat must normally be applied prior
to the addition of any water or solvent based lotion add on since
the shrink temperatures would be usually be higher than the boiling
point of water at normal atmospheric pressure. The use of a
pressurized chamber would enable the volatile components of the add
on to remain stable and associated with the wipe as the heat is
added to initiate the shrink and thus the Z dimension as long as
the pressure in the chamber is raised in conjunction with an
increase in pressure such that the characteristic of the solvent
carrying the actives on the wiper stay in the liquid region of the
solvent phase equilibrium diagram. An immediate cooling would be
required while the pressure is applied and the cooling and release
of the pressure would not affect the Z dimension formation as it
would be irreversible due to the characteristics of the thermal
contraction and expansion of the web components. In an alternative
embodiment a vacuum could be applied in addition to heat.
[0116] In one example, outer non-shrink layers consisting of
woodpulp spunlaced polyester blend, having a 48-62 gsm basis
weight, 180-280 micron thickness, greater than 2500 N/m dry MD
tensile, 500 N/m dry CD tensile, 2000 N/m wet MD tensile, 400 N/m
wet CD tensile, and greater than 300% w/w liquid absorbent capacity
were bonded ultrasonically to an inner layer of 100% spunlace
polyester absorbent material. The substrates were bonded in a 0.5
inch diamond pattern, a 0.75 inch diamond pattern, and a 1.5 inch
triangle pattern. The substrates were also bonded in cross
dimension patterns of 0.5 inch, 1.0 inch, and 2.0 inch between
bonding lines. In another example, outer non-shrink layers of
woodpulp spunlaced polyester blend, having a 48-62 gsm basis
weight, 180-280 micron thickness, greater than 2500 N/m dry MD
tensile, 500 N/m dry CD tensile, 2000 N/m wet MD tensile, 400 N/m
wet CD tensile, and greater than 300% w/w liquid absorbent capacity
were bonded to a layer of carded PET using a glue laminator in the
cross dimension using a 5 to 1 tension difference between the
substates when bonded.
[0117] The substrates were wound into rolls and subjected to
heating. The rolls were heated in an oven at 400 to 450.degree. F.
for 30 to 45 seconds to give an approximate 30% shrink for the
shrink layer. For substrates bonded in the cross dimension, the
further the bond distance the greater the Z-dimension thickness
change. For substrates bonded in a diamond or triangle pattern, the
substrate curls to give a Z-dimension thickness change. A laminated
structure using the diamond pattern as described in the application
exposed to 200 C in an oven for 10 seconds developed a greater than
100% increase in overall thickness.
[0118] The rolls could in the same fashion be heated inside
consumer canisters or heated as individual items inside packages or
heated as sheets inside tubs. The substrate could be sold to the
consumer in wet form or dry form.
[0119] While various patents have been incorporated herein by
reference, to the extent there is any inconsistency between
incorporated material and that of the written specification, the
written specification shall control. In addition, while the
invention has been described in detail with respect to specific
embodiments thereof, it will be apparent to those skilled in the
art that various alterations, modifications and other changes may
be made to the invention without departing from the spirit and
scope of the present invention. It is therefore intended that the
claims cover all such modifications, alterations and other changes
encompassed by the appended claims.
* * * * *