U.S. patent application number 10/958791 was filed with the patent office on 2005-04-14 for cleaning pad and cleaning implement.
Invention is credited to Allie, Edward Phillip, Breidenbach, Vincent Sean, O'Donnell, Hugh Joseph, Pung, David John.
Application Number | 20050076936 10/958791 |
Document ID | / |
Family ID | 34434990 |
Filed Date | 2005-04-14 |
United States Patent
Application |
20050076936 |
Kind Code |
A1 |
Pung, David John ; et
al. |
April 14, 2005 |
Cleaning pad and cleaning implement
Abstract
The present invention relates to disposable cleaning pads for
removable attachment to a cleaning implement, the cleaning pad
comprising an absorbent structure, and a plurality of reservoirs
defined in the absorbent structure, formed by bonding or embossing
throughout the thickness of the absorbent structure.
Inventors: |
Pung, David John; (Loveland,
OH) ; O'Donnell, Hugh Joseph; (Cincinnati, OH)
; Allie, Edward Phillip; (West Chester, OH) ;
Breidenbach, Vincent Sean; (Middletown, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
34434990 |
Appl. No.: |
10/958791 |
Filed: |
October 5, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60509559 |
Oct 8, 2003 |
|
|
|
Current U.S.
Class: |
134/6 ; 15/208;
15/209.1; 15/228 |
Current CPC
Class: |
B32B 38/06 20130101;
A47L 13/17 20130101; A47L 13/20 20130101; B32B 3/28 20130101; B32B
7/04 20130101; B32B 2432/00 20130101 |
Class at
Publication: |
134/006 ;
015/228; 015/209.1; 015/208 |
International
Class: |
A47L 013/16 |
Claims
What is claimed is:
1. A disposable cleaning pad for removable attachment to a cleaning
implement, the cleaning pad comprising an absorbent structure, and
a plurality of reservoirs defined in the absorbent structure,
formed by bonding or embossing throughout the thickness of the
absorbent structure.
2. A disposable cleaning pad according to claim 1, wherein the
cleaning pad further comprises a means for removably attaching the
cleaning pad to a cleaning implement.
3. A disposable cleaning pad according to claim 1, wherein the
cleaning pad is pre-moistened with a liquid cleaning
composition.
4. A cleaning pad according to claim 1, wherein the absorbent
structure comprises an upper surface and a lower surface, and the
reservoirs are formed by bonding together the upper surface and the
lower surface of the absorbent structure at selected locations.
5. A cleaning pad according to claim 1, wherein the absorbent
structure comprises an upper sheet, a lower sheet, and an absorbent
core positioned between the upper and lower sheets, wherein the
fluid reservoirs are defined by bonds formed between the upper
sheet and the lower sheet, and each fluid reservoir comprises a
discrete portion of the absorbent core.
6. A cleaning pad according to claim 1, wherein the reservoirs are
defined by intersecting bond lines extending in different
directions across the cleaning pad.
7. A cleaning pad according to claim 6, wherein the cleaning pad
has side edges and the bond lines extend from one side edge of the
cleaning pad to another side edge of the cleaning pad.
8. A cleaning pad according to claim 7, wherein the bond lines
define an acute angle with a side edge of the cleaning pad.
9. A cleaning pad according to claim 7, wherein the cleaning pad is
substantially square or rectangular in shape, and wherein the bond
lines are substantially parallel to the side edges of the cleaning
pad.
10. A cleaning pad according to claim 1, wherein the reservoirs are
defined by a plurality of bond sites separated from one another by
a distance in the range 0.015 to 0.05 in.
11. A cleaning pad according to claim 1, wherein the reservoirs are
defined by a plurality of bond sites, each bond site having an
aspect ratio of less than 0.01.
12. A cleaning pad according to claim 1, wherein the reservoirs are
defined by a plurality of bond sites, each bond site having a
surface area of less than 0.003 sq in.
13. A cleaning pad according to claim 1, wherein the total area of
bonding comprises less than 10% of the area of the absorbent
structure.
14. A cleaning pad according to claim 1, wherein the absorbent
structure comprises an upper surface and a lower surface, and the
reservoirs are formed by embossing the absorbent structure so as to
bring the upper and lower surfaces into contact with one another at
selected locations.
15. A disposable cleaning pad for removable attachment to a
cleaning implement, the cleaning pad comprising an absorbent
structure, and a plurality of reservoirs defined in the absorbent
structure, wherein at least some of the reservoirs contain
superabsorbent material.
16. A cleaning pad according to claim 15, wherein the absorbent
structure comprises an upper sheet, a lower sheet, and an absorbent
core positioned between the upper and lower sheets, and wherein
each reservoir comprises a discrete portion of the absorbent
core.
17. A cleaning pad according to claim 1, wherein the fluid
reservoirs have a shape selected from circles, squares, rectangles,
diamonds, ovals, triangles, hexagons and combinations thereof.
18. A cleaning pad according to claim 1, wherein adjacent
reservoirs are in fluid communication with one another.
19. A cleaning pad according to claim 1, which further comprises a
scrubbing strip of abrasive material.
20. A cleaning implement comprising a handle; a head portion
attached to the handle; and removably attached to the head portion,
a cleaning pad as defined in claim 1.
21. A cleaning implement according to claim 20, wherein the head
portion is pivotally attached to the handle.
22. A cleaning kit comprising a cleaning implement comprising a
handle and a head portion; and a cleaning pad as defined in any of
claim 1, for removable attachment to the head portion.
23. A method of cleaning a hard surface, comprising providing a
cleaning implement comprising a handle and a head portion attached
thereto; removably attaching to the head portion a cleaning pad as
defined in any of claim 1; wiping the surface to be cleaned with
the cleaning pad; and, optionally, removing the cleaning pad.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/509559, filed on Oct. 8, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates to cleaning pads and cleaning
implements for cleaning hard surfaces, and in particular floors.
More particularly, the present invention relates to pre-moistened
cleaning pads.
BACKGROUND OF THE INVENTION
[0003] Numerous implements are known for cleaning hard surfaces
such as tiled floors, linoleum floors, hardwood floors, counter
tops and the like. In the context of cleaning floors, suitable
implements typically comprise a handle and means for applying a
liquid cleaning composition. Some implements are reusable,
including mops containing cotton strings, cellulose and/or
synthetic strips, sponges, and the like. While these mops are
successful in removing many soils from hard surfaces, they
typically require the inconvenience of performing one or more
rinsing steps during use to avoid saturation of the material with
dirt, soil, and other residues. This requires the use of a separate
container to perform the rinsing step(s), and typically these
rinsing steps fail to sufficiently remove dirt residues. This can
result in redeposition of significant amounts of soil during
subsequent passes of the mop. Furthermore, as reusable mops are
used over time, they become increasingly soiled and malodorous.
This negatively impacts subsequent cleaning performance.
[0004] To alleviate some of the negative attributes associated with
reusable cleaning implements, mops having disposable cleaning pads
have been provided. For example, WO-A-0027271 describes a cleaning
implement comprising a handle and a head portion pivotally attached
thereto, and a removable cleaning pad for attachment to the head
portion, the cleaning pad comprising at least one absorbent layer
and various other optional features. The absorbent layer may be
pre-moistened, or impregnated, with a liquid cleaning composition
prior to attachment to the head portion of the cleaning implement,
either by the manufacture of the cleaning pads, or by the
consumer.
[0005] Pre-moistened cleaning pads of this type are commercially
available from the Applicant under the registered trade mark
Swiffer Wet.RTM.. Typically, a plurality of pre-moistened pads are
provided in a container in such a manner as to allow easy
attachment to the head of a cleaning implement, by inserting the
head of the cleaning implement into the container, thus avoiding
extensive contact between the cleaning pad and the consumer's
hands. Suitable instructions are also provided. However, despite
these instructions, it is believed that about 75% of consumers
attach pre-moistened cleaning pads to a mop head while the mop is
held inverted between their legs. It is suspected that this is a
habit created from the use of dry cleaning pads. Irrespective of
this, attachment of the cleaning pad tends to take several seconds,
allowing drippage to occur while the pad is being held essentially
upright. It would be desirable to reduce this drippage.
[0006] EP 0 112 654 (assigned to Unilever NV) describes a cleaning
substrate having an absorbent core sandwiched between two nonwoven
outer layers. In order to bond the various layers together to form
a unitary structure, the absorbent core is perforated at regular
intervals through which the outer layers are spotbonded together.
Other methods for bonding nonwoven layers together are described in
U.S. Pat. No. 5,964,742, and in U.S. Pat. No. 3,855,046 (both
assigned to Kimberly-Clark Worldwide, Inc.).
SUMMARY OF THE INVENTION
[0007] According to a first aspect of the present invention,
various types of cleaning pad are defined in claims 1 and 15. The
discrete fluid reservoirs formed in the above-mentioned cleaning
pads restrain fluid flow to the edges of the pad, thereby reducing
drippage experienced on attaching the cleaning pad to a cleaning
implement while held inverted between a consumer's legs.
[0008] According to a second aspect of the present invention a
cleaning implement comprises a handle; a head portion attached to
the handle; and, removably attached to the head portion, a cleaning
pad of any of the types described above.
[0009] According to a third aspect of the present invention, a
cleaning kit comprises a cleaning implement comprising a handle and
a head portion attached thereto, and a cleaning pad of any of the
types described above.
[0010] According to a fourth aspect of the present invention, a
method of cleaning a hard surface (eg. a floor) comprises providing
a cleaning implement comprising a handle and a head portion
attached thereto; removably attaching to the head portion a
cleaning pad of any of the types described above; wiping the
surface to be cleaned with the cleaning pad; and optionally,
removing the cleaning pad.
DEFINITIONS
[0011] As used herein, the term "x-y dimension" refers to the plane
orthogonal to the thickness of the cleaning pad, or a component
thereof. The x and y dimensions correspond to the length and width,
respectively, of the cleaning pad or a pad component. In this
context, the length of the pad is the longest dimension of the pad,
and the width the shortest. In general, in use, a cleaning
implement will be moved in a direction parallel to the y-dimension
(or width) of the pad. Of course, the present invention is not
limited to the use of cleaning pads having four sides. Other
shapes, such as circular, elliptical, and the like, can also be
used. When determining the width of the pad at any point in the
z-dimension, it is understood that the pad is assessed according to
its intended use.
[0012] As used herein, the term "z-dimension" refers to the
dimension orthogonal to the length and width of the cleaning pad of
the present invention, or a component thereof. The z-dimension
therefore corresponds to the thickness of the cleaning pad or a pad
component.
[0013] As used herein, an "upper" sheet or layer of a cleaning pad
is a sheet or 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" sheet or layer conversely means a sheet or layer of a
cleaning pad 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).
[0014] As used herein, the "leading" or "front" edge of a cleaning
pad is that edge which on a forwards wiping motion crosses the
surface to be cleaned in advance of the opposing "trailing" or
"rear" edge of the cleaning pad.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The cleaning pad comprises an absorbent structure, which may
be a monolayer or multilayer structure. In a preferred embodiment
the absorbent structure comprises an absorbent core sandwiched
between an upper sheet and a lower sheet. In this case, each
discrete reservoir comprises a discrete portion of the absorbent
core. However, an absorbent structure comprising only two layers is
also envisaged. Furthermore, the cleaning pad may comprise layers
in addition to its absorbent structure.
[0016] The absorbent structure comprises any material capable of
absorbing and retaining fluid during use. Typically, the absorbent
structure comprises fibrous material, preferably nonwoven fibrous
material. Fibers useful in the present invention include those that
are naturally occurring (modified or unmodified), as well as
synthetically made fibers. Examples of suitable unmodified/modified
naturally occurring fibers include cotton, Esparto grass, bagasse,
kemp, flax, silk, wool, wood pulp, chemically modified wood pulp,
jute, ethyl cellulose, and cellulose acetate. Suitable synthetic
fibers can be made from polyvinyl chloride, polyvinyl fluoride,
polytetra-fluoroethylene, 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. The absorbent core can
comprise solely naturally occurring fibers, solely synthetic
fibers, or any compatible combination of naturally occurring and
synthetic fibers.
[0017] The fibers useful herein can be hydrophilic, hydrophobic or
can be a combination of both hydrophilic and hydrophobic fibers. As
used herein, the term "hydrophilic" is used to refer to surfaces
that are wettable by is aqueous fluids deposited thereon.
Hydrophilicity and wettability are typically defined in terms of
contact angle and the surface tension of the fluids and solid
surfaces involved. This is discussed in detail in the American
Chemical Society publication entitled "Contact Angle, Wettability
and Adhesion", edited by Robert F. Gould (Copyright 1964. A surface
is said to be wetted by a fluid (i.e., hydrophilic) when either the
contact angle between the fluid and the surface is less than
90.degree., or when the fluid tends to spread spontaneously across
the surface, both conditions normally co-existing. Conversely, a
surface is considered to be "hydrophobic" if the contact angle is
greater than 90.degree. and the fluid does not spread spontaneously
across the surface.
[0018] The particular selection of hydrophilic or hydrophobic
fibers will depend upon the other materials included in the
cleaning pad, for instance in different absorbent layers. That is,
the nature of the fibers will be such that the cleaning pad
exhibits the necessary fluid delay and overall fluid absorbency.
Suitable hydrophilic fibers for use in the present invention
include cellulosic fibers, modified cellulosic fibers, rayon,
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.
[0019] Suitable wood pulp fibers can be obtained from well-known
chemical processes such as the Kraft and sulfite processes. It is
especially preferred to derive these wood pulp fibers from southern
soft woods due to their premium absorbency characteristics. These
wood pulp fibers can also be obtained from mechanical processes,
such as ground wood, refiner mechanical, thermomechanical,
chemimechanical, and chemi-thermomechanical pulp processes.
Recycled or secondary wood pulp fibers, as well as bleached and
unbleached wood pulp fibers, can be used.
[0020] 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.
[0021] Where fibers are used as the absorbent structure (or a
constituent component thereof), the 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 pad.
[0022] 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 inter fiber
capillary pore size.
[0023] 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. Preferably, the
melting point of this thermoplastic material will be less than
about 90.degree. C., and preferably 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 absorbent structures, when used in the
cleaning pads, are likely to be stored. The melting point of the
thermoplastic material is typically no lower than about 50.degree.
C.
[0024] The thermoplastic materials, and in particular the
thermoplastic fibers, can be made from a variety of thermoplastic
polymers, including polyolefins such as polyethylene (e.g.,
PULPEX.RTM.) and polypropylene, polyesters, copolyesters, polyvinyl
acetate, polyethylvinyl acetate, polyvinyl chloride, polyvinylidene
chloride, polyacrylics, polyamides, copolyamides, polystyrenes,
polyurethanes and copolymers of any of the foregoing such as vinyl
chloride/vinyl acetate, and the like. Depending upon the desired
characteristics, suitable thermoplastic materials include
hydrophobic fibers that have been made hydrophilic, 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. 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 sq. of centimeter of thermoplastic fiber.
[0025] Suitable thermoplastic fibers can be made from a single
polymer (monocomponent fibers), or can be made from more than one
polymer (e.g., bicomponent fibers). As used herein, "bicomponent
fibers" refers to 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.
[0026] Suitable bicomponent fibers for use in the present invention
can include sheath/core fibers having the following polymer
combinations: polyethylene/poly-propylene, polyethylvinyl
acetate/polypropylene, poly-ethylene/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 and Chisso Corp.).
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. Preferred bicomponent fibers
comprise a copolyolefin bicomponent fiber comprising less than
about 81% polyethylene terephthalate core and a less than about 51%
copolyolefin sheath. Such a preferred bicomponent fiber is
commercially available from the Hoechst Celanese Corporation, in
New Jersey, under the trade name CELBOND.RTM. T-255. The amount of
bicomponent fibers will preferably vary according to the density of
the material in which it is used.
[0027] Methods for preparing thermally bonded fibrous materials are
described in U.S. Pat. No. 5,607,414 (Richards et al), issued Mar.
4, 1997; and U.S. Pat. No. 5,549,589 (Horney et al) issued Aug. 27,
1996 (see especially columns 9 to 10).
[0028] It may be desirable to include in the absorbent structure a
material having a relatively high capacity (in terms of grams of
fluid per gram of absorbent material). As used herein, the term
"superabsorbent material" means any absorbent material having a g/g
capacity for water of at least about 15 g/g, when measured under a
confining pressure of 0.3 psi. Because a majority of the cleaning
fluids useful with the present invention are aqueous based, it is
preferred that the superabsorbent materials have a relatively high
g/g capacity for water or water-based fluids.
[0029] Superabsorbent gelling polymers useful in the present
invention include a variety of water-insoluble, but water-swellable
(gelling) polymers capable of absorbing large quantities of fluids.
Such polymeric materials are also commonly referred to as
"hydrocolloids", and can include polysaccharides such as
carboxymethyl starch, carboxymethyl cellulose, and hydroxypropyl
cellulose; nonionic types such as polyvinyl alcohol and polyvinyl
ethers; cationic types such as polyvinyl pyridine, polyvinyl
morpholinione, and N,N-dimethylaminoethyl or N,N-diethylaminopropyl
acrylates and methacrylates, and the respective quaternary salts
thereof. Well-known materials and are described in greater detail,
for example, in U.S. Pat. No. 4,076,663 (Masuda et al), issued Feb.
28, 1978, and in U.S. Pat. No. 4,062,817 (Westerman), issued Dec.
13, 1977.
[0030] Preferred superabsorbent gelling polymers contain carboxy
groups. These polymers include hydrolyzed starch-acrylonitrile
graft copolymers, partially neutralized hydrolyzed
starch-acrylonitrile graft copolymers, starch-acrylic acid graft
copolymers, partially neutralized starch-acrylic acid graft
copolymers, saponified vinyl acetate-acrylic ester copolymers,
hydrolyzed acrylonitrile or acrylamide copolymers, slightly network
crosslinked polymers of any of the foregoing copolymers, partially
neutralized polyacrylic acid, and slightly network crosslinked
polymers of partially neutralized polyacrylic acid. These polymers
can be used either solely or in the form of a mixture of two or
more different polymers. Examples of these polymer materials are
disclosed in U.S. Pat. No. 3661,875, U.S. Pat. No. 4,076,663, U.S.
Pat. No. 4,093,776, U.S. Pat. No. 4,666,983, and U.S. Pat. No.
4,734,478.
[0031] Most preferred polymer materials for use in making the
superabsorbent gelling polymers are slightly network crosslinked
polymers of partially neutralized polyacrylic acids and starch
derivatives thereof. Most preferably, the hydrogel-forming
absorbent polymers comprise from about 50 to about 95%, preferably
about 75%, neutralized, slightly network crosslinked, polyacrylic
acid (i.e. poly (sodium acrylate/acrylic acid)). Network
crosslinking renders the polymer substantially water-insoluble and,
in part, determines the absorptive capacity and extractable polymer
content characteristics of the superabsorbent gelling polymers.
Processes for network crosslinking these polymers and typical
network crosslinking agents are described in greater detail in U.S.
Pat. No. 4,076,663.
[0032] Where superabsorbent material is included in the absorbent
structure, the absorbent structure will preferably comprise at
least about 15%, by weight of the absorbent structure, more
preferably at least about 20%, still more preferably at least about
25%, of the superabsorbent material.
[0033] Where the cleaning pad comprises an absorbent core, the core
may comprise any of the above materials. Similarly, where the
cleaning pad comprises an upper sheet and a lower sheet, they too
may comprise any of the above absorbent materials, or may be
non-absorbent but fluid pervious in nature. If the upper and/or
lower sheet is absorbent, it will typically have lower absorbency
than the absorbent core. The upper sheet and the lower sheet may
comprise separate sheet materials, or may be portions of the same
sheet material, for instance which is wrapped around the absorbent
core. Furthermore, the upper sheet and lower sheet may each
independently comprise a monolayer or multilayer structure, and
additional components may be included between the upper and/or
lower sheet and the absorbent core.
[0034] The cleaning pad may comprise components, which may take the
form of layers, in addition to the absorbent structure.
[0035] The cleaning pad comprises a plurality of discrete fluid
reservoirs. As used herein, "discrete" fluid reservoirs are
reservoirs for containing a fluid, and in particular a liquid
cleaning composition, which are separated from one another, either
simply by the walls of the individual reservoirs if the reservoirs
are adjacent one another, or by portions of the cleaning pad if the
reservoirs are spaced apart.
[0036] Typically, the reservoirs are formed by bonding or embossing
throughout the thickness of the absorbent structure. In the context
of a monolayer absorbent structure, this typically means that the
opposing surfaces of the absorbent structure are brought together
at selected locations. In the context of a multilayer absorbent
structure, typically this means that the outer layers of the
multilayer structure are brought together, preferably by bonding
those layers together, at selected locations. For instance, where
the absorbent structure comprises an upper sheet, a lower sheet,
and an absorbent core positioned therebetween, preferably the upper
sheet is bonded to the lower sheet at selected locations to define
discrete fluid reservoirs, with the result that each reservoir will
contain a discrete portion of the absorbent core.
[0037] Bonding may be achieved by the application of heat and/or
pressure or ultrasonically. Typically, when the reservoirs are
formed by bonding through the cleaning pad, the bond strength will
be greater than 30 grams force, without the use of an adhesive.
[0038] A virtually unlimited number of shapes and sizes of fluid
reservoirs may be envisaged. For instance, the reservoirs may have
a shape selected from circles, squares, rectangles, diamonds,
ovals, triangles, hexagons and combinations thereof.
[0039] Other shapes may also be envisaged. In the latter case, the
reservoirs may be formed by intersecting bond lines, preferably
extending between different side edges of the cleaning pad. For
instance, the bond lines may form an acute angle with the side
edges of the cleaning pad, or they may extend substantially
parallel to those side edges.
[0040] Preferably, adjacent fluid reservoirs are in fluid
communication with one another. By this we mean that fluid is able
to pass between adjacent reservoirs. However, fluid communication
should be somewhat limited, in order to achieve the desired
restraint on fluid flow to the side edges of the cleaning pad, to
reduce or avoid drippage during attachment to a cleaning implement.
Fluid communication maybe achieved through provision of narrow
channels between the reservoirs, which may result from the process
used to form the reservoirs, as is described in more detail below.
Such channels will typically have a cross-sectional area in the
range 0.01 to 0.05 sq. in., typically 0.015 to 0.045 sq. in.
[0041] A preferred bonding method for forming the reservoirs is
described in U.S. patent application Ser. No. 10/456288, filed on
Jun. 6, 2003 (McFall et al.). This method is now described in the
context of a cleaning pad comprising an upper sheet, a lower sheet
and an absorbent core sandwiched therebetween, but is applicable to
other absorbent structures. In essence, the method comprises
localized compression of the cleaning pad which causes the core
material to fracture and separate (ie. move away from the pressure
point), while the upper sheet and the lower sheet remain intact. As
a result there is a clear path for the upper sheet and the lower
sheet to bond together, and preferably very little (if any) of the
core material is actually left in the bond sites. Rather, discrete
portions of the core material is enclosed within the resulting
fluid reservoirs.
[0042] In this method, the upper sheet and the lower sheet comprise
any material(s) capable of bonding together by the application of
heat and/or pressure, adhesives or ultrasonics. Suitable materials
include woven and nonwoven materials; polymeric materials such as
apertured formed thermoplastic films, apertured or unapertured
plastic films, and hydroformed thermoplastic films; porous foams,
reticulated foams; reticulated thermoplastic films; and
thermoplastic scrims. Suitable woven and nonwoven materials can be
comprised of natural fibers or synthetic fibers as described
before, or from a combination of natural and synthetic fibers.
Preferred materials are thermoplastics materials. However,
particularly if adhesives or other types of bonding are used,
materials other than thermoplastic materials may be preferred. For
instance, the top sheet and backing sheet may each comprise a
cellulosic material that can be bonded to itself by hydrogen
bonding.
[0043] The bonding process typically comprises feeding a laminate,
for instance comprising an upper sheet, an absorbent core and a
lower sheet, through at least a pair of cylindrical rolls, with at
least one of the rolls having a relief pattern on its surface
formed by a plurality of protruberances or pattern elements
extending outwardly from the surface of the roll.
[0044] The other cylindrical roll serves as an anvil member, and
together the patterned roll and the anvil roll define a pressure
biased nip therebetween. Preferably, the anvil is smooth-surfaced,
however both rolls may have a relief pattern thereon. The patterned
roll and anvil roll are preferably biased towards each other with a
loading of from about 20,000 psi (about 140 MPa) to about 200,000
psi (about 1400 MPa).
[0045] The patterned roll and the anvil roll are preferably driven
in the same direction at different speeds, so that there is a
surface velocity differential therebetween. The surface velocity
differential preferably has a magnitude of from about 2 to about
40% of the roll having the lower surface velocity, more preferably
between about 2 to about 20%. The anvil roll is preferably operated
at a surface velocity that is greater than that of the patterned
roll. It is also possible, however, that high line velocities for
bonding to occur at zero velocity differential.
[0046] The relief pattern may take a variety of forms, and can be
continuous or intermittent, depending upon the nature of the fluid
reservoirs desired to be formed. If the relief pattern is
continuous, the result will be a continuous bond. If the relief
pattern is intermittent, the result will be that apertures, or
gaps, exist in the bond, which may allow for fluid communication
between adjacent reservoirs, as described above. In this case, the
bond may be considered as comprising a plurality of bond sites, the
dimensions of which depend upon the size, shape and distance of
separation of the protruberances making up the relief pattern.
Preferably, the protruberances, and therefore the resulting bond
sites, have an aspect ratio of less than 0.10, more preferably in
the range from 0.02 to 0.085, and most preferably in the range from
0.03 to 0.083. In this context, the aspect ratio is defined as
minor axis:major axis. Furthermore, the separation, or distance
between adjacent bond sites is preferably in the range 0.015 to
0.05 in.
[0047] The protruberances or pattern elements may also take a
variety of forms, as can the land surfaces (ie. the outermost
surfaces) of the protruberances. The protruberances generally have
side walls that are not perpendicular to the surface of the
respective cylindrical roll. Preferably, for instance, the side
walls form an angle of greater than 45.degree. than 90.degree.,
preferably between about 70.degree. to 90.degree., with the surface
of the cylindrical roll.
[0048] Suitable shapes for the land surfaces include, but are not
limited to, oval, circular, rectangular, square and triangular. The
land surfaces may also be of a variety of sizes, for instance
having an area ranging from 0.0001 sq. in. to 0.003 sq. in.,
resulting in a bond site of substantially the same area.
[0049] Optionally, prior to bonding, the absorbent core may be slit
or cut to form particulate material, in a pattern corresponding to
the desired bonded pattern. It is, however, important that the
materials from which the upper sheet and lower sheet are selected
are such that they remain intact during this optional cutting step.
Cutting may be achieved by passing the laminate of absorbent core,
upper sheet and lower sheet through a pair of cylindrical rolls,
each of which has a patterned surface thereon, preferably formed by
a plurality of ridges and valleys defining a plurality of
triangularly-shaped teeth. The cylindrical roll subject the
laminate to a mechanical straining process which applies a force
that is greater than the yield-to-break point of the absorbent
core, but less than that of the upper sheet and the lower sheet.
Thus, the absorbent core is at least partially slit without
slitting the upper sheet or the lower sheet.
[0050] Another bonding method for forming the reservoirs comprises
ultrasonic bonding, and suitable equipment for this purpose
includes Branson Ultrasonic Unit Model 900 BCA. For example, the
components of the cleaning pad to be bonded are arranged on a plate
patterned according to the desired reservoirs, and compressed, for
instance using a pressure of about 30 psig, while welding the
cleaning pad ultrasonically.
[0051] The selection of bond area is important for minimizing a
performance reduction in absorption. As can be expected, the higher
the bond area, the greater the reduction in pad absorption, and
thus pad mileage. Preferably the total bond area across the
entirety of the cleaning pad (in the x-y plane) is less than 10%,
more preferably less than 5%, and most preferably less than 3%.
Bond area is measured, for instance, using Auto Cad LT 98 software
in accordance with the following method:
[0052] 1. Draw the pattern
[0053] 2. Moving right to left and top to bottom on the pattern,
find the repeat.
[0054] 3. Draw a box that encompasses one repeat in the top to
bottom and left to right.
[0055] 4. Count the number of elements in the box that was just
drawn (eg. 45).
[0056] 5. Calculate the footprint of the elements (e.g. 0.010
in..times.0.1 in.=0.001 in..sup.2).
[0057] 6. Multiply footprints by the number of elements in the box
(eg. 0.001 in..times.45 in.=0.045 in.sup.2).
[0058] 7. In AutoCad LT 98 measure the box that was drawn earlier,
length and width.
[0059] 8. Multiply the length by the width (eg. 1 in..times.2 in.=2
in..sup.2).
[0060] 9. Divide the area of the elements by the area of the box
(eg. 0.045 in.sup.2/2 in..sup.2=0.0225).
[0061] 10. Multiply that number by 100 to get your bond area
percentage (eg. 0.0225.times.100=2.25%).
[0062] The depth of bonding relative to the unbonded area of the
cleaning pad (ie. prior to any bonding) is also important to the
consumer's perception of scrubbing ability and actual scrubbing
performance. Preferably, the cleaning pad has a bond depth index
(BDI) of 0.15, and preferably less than 0.10, to achieve a good
balance between absorption performance, drippage and aesthetic
considerations. The BDI is calculated by dividing the average
caliper of the bond area by the average caliper of the unbonded
area, ie. prior to any bonding. Typically, the cleaning pad has an
unbonded thickness of at least up to 2 mm, preferably up to 4
mm.
[0063] The cleaning pad may comprise various optional features. For
instance, the cleaning pad may comprise a scrubbing strip,
preferably located on a portion of the pad which does not make
contact with the surface to be cleaned during the normal cleaning
operation. In other words, the scrubbing strip is preferably
positioned on the cleaning pad such that, on attachment to the head
portion of a cleaning implement, the scrubbing strip extends along
a side edge of the head portion. Alternatively, the scrubbing strip
may be positioned on the floor-contacting lower surface of the
cleaning pad.
[0064] The scrubbing strip necessarily comprises an abrasive
material, to remove tough stains. Suitable materials include those
often used for making scouring pads, typically polymers or polymer
blends with or without specific abrasives. Examples of suitable
polymers include thermoplastic polymers such as polypropylene, high
density polyethylene, polyesters (eg., polyethylene terephthalate),
nylon, polystyrene, and blends and copolymers thereof.
[0065] An alternative to using materials found in typical scouring
pads is to use brushes containing bristles to achieve scrubbing.
Such bristles are typically composed of polymer or polymer blends,
with or without abrasives. In the context of brushes, bristles made
of nylon again are preferred because of rigidity, stiffness, and/or
durability. A preferred nylon bristle is that commercially
available from 3M Corp. under the trade name Tynex.RTM. 612 nylon.
These bristles have shown less water absorption versus commercial
Nylon 66. Reducing the ability of the present adhesive scrubbing
strips to absorb water is important since water absorption
decreases bristle stiffness and recovery while impacting scrubbing
ability.
[0066] Another approach is to use netting or scrim materials to
form the scrubbing strip. Again, the netting or scrim is typically
composed of a polymer or polymer blend, either with or without
abrasives. The netting or scrim is typically wrapped around a
secondary structure to provide some bulk. The shape of the holes in
the netting can include, but is not limited to, a variety of shapes
such as squares, rectangles, diamonds, hexagons or mixtures
thereof. Typically, the smaller the area composed by the holes in
the netting the greater the scrubbing ability. This is primarily
due to the fact that there are more points where the scrim material
intersects, as it is these intersection points that will contact
the floor. An alternative to wrapping netting or scrim is to apply
molten extruded polymers directly onto a secondary structure such
as a non-woven. Upon curing the polymer would create high point
stiffer material as compared to the secondary non-woven which in
turn provides scrubbing ability.
[0067] Yet another alternative is for the scrubbing strip to
comprise abrasive or coarse particulate material. A suitable
particulate material comprises coarse inks available from
Polytex.RTM. or coarse polymers from Vinamul, like Acrylic
ABX-30.
[0068] The scrubbing strip may be a monolayer or multilayer
structure. Preferred scrubbing layers take the form of film
materials, provided that they have the necessary flexural rigidity
to withstand repeated scrubbing actions. Suitable film materials
generally have a thickness of at least 2 mils and a flexural
rigidity of at least 0.10 g cm.sup.2/cm, measured using the
Kawabata bending tester.
[0069] Preferred film materials are pervious to liquids, and in
particular liquids containing soils, and yet are non-absorbent and
have a reduced tendency to allow liquids to pass back through their
structure and rewet the surface being cleaned. Thus, the surface of
the film tends to remain dry during the cleaning operation, thereby
reducing filming and streaking of the surface being cleaned and
permitting the surface to be wiped substantially dry.
[0070] Preferably the film material comprises a plurality of
protrusions extending outwardly from the film surface and away from
the body of the cleaning pad. Alternatively, or additionally, the
film may comprise a plurality of apertures. The protrusions and/or
apertures formed in the above-described film materials may be of a
variety of shapes and/or sizes.
[0071] The cleaning pad may comprise a scrubbing layer which, when
attached to the cleaning implement, extends over the lower surface
of the head portion of that cleaning implement. The lower sheet of
the cleaning pad may take the form of a scrubbing layer. Typically,
the scrubbing layer is outermost on the cleaning pad, and thus
contacts the surface to be cleaned during the normal course of the
cleaning operation. In this case, the scrubbing layer must
necessarily be of lower abrasiveness than the scrubbing strip, in
order not to damage the surface being cleaned.
[0072] The scrubbing layer may be a mono-layer or a multilayer
structure. A wide range of materials are suitable for use in the
scrubbing layer, for instance as disclosed in WO-A-0027271. In
particular, the scrubbing layer may comprise woven and nonwoven
materials; polymeric materials such as apertured formed
thermoplastic films, apertured plastic films, and hydroformed
thermoplastic films; porous foams; reticulated foams; reticulated
thermoplastic films; and thermoplastic scrims.
[0073] The cleaning pad also typically comprises attachment means
for attaching the pad to a cleaning implement. Alternatively, the
cleaning implement itself may include suitable attachment means.
For instance, the cleaning pad may have an attachment layer that
allows the pad to be connected to the implement's handle or head
portion. The attachment layer can be necessary in those embodiments
where the absorbent layer is not suitable for attaching the pad to
the cleaning implement. The attachment layer can also function as a
means to prevent fluid flow through the top surface (i.e., the
handle-contacting surface) of the cleaning pad, and can further
provide enhanced integrity of the pad. As with the scrubbing and
absorbent layers, the attachment layer can consist of a mono-layer
or a multi-layer structure, so long as it meets the above
requirements.
[0074] In a preferred embodiment of the present invention, the
attachment layer will comprise a surface which is capable of being
mechanically attached to the head portion of a cleaning implement
by use of known hook and loop technology. In such an embodiment,
the attachment layer will comprise at least one surface which is
mechanically attachable to hooks that are permanently affixed to
the bottom surface of the head portion.
[0075] In an alternative embodiment, the attachment layer can have
a y-dimension (width) that is greater than the y-dimension of the
other cleaning pad elements such that the attachment layer can then
engage attachment structures located on a mop head of a handle of a
cleaning implement.
[0076] The cleaning pad may be designed to have multiple cleaning
surfaces or edges, each of which contact the soiled surface during
the cleaning operation. In the context of a cleaning implement such
as a mop, these surfaces or edges are provided such that during the
typical cleaning operation (i.e., where the implement is moved back
and forth in a direction substantially parallel to the pad's
y-dimension or width), each of the surfaces or edges contact the
surface being cleaned as a result of "rocking" of the cleaning pad.
The effect of multiple edges is achieved by constructing the pad
such that it has multiple widths through its dimension. That is,
these multiple widths form a plurality of surfaces or edges along
the front and rear of the pad. This aspect is discussed in more
detail in WO-A-0027271.
[0077] The cleaning pad may also include one or more
"free-floating" functional cuffs. Such cuffs improve the cleaning
performance of the cleaning pad, by improving particulate pick-up.
As a cleaning pad comprising functional cuff(s) is wiped back and
forth across a hard surface, the functional cuff(s) "flip" from
side to side, thus picking-up and trapping particulate matter.
Cleaning pads having functional cuff(s) exhibit improved pick-up
and entrapment of particulate matter, which are typically found on
a hard surfaces, and have a reduced tendency to redeposit such
particulate matter on the surface being cleaned. Functional cuffs
can comprise a variety of materials, including, but not limited to,
carded polypropylene, rayon or polyester, hydroentangled polyester,
spun-bonded polypropylene, polyester, polyethylene, cotton,
polypropylene, or blends thereof. Functional cuffs can be formed as
an integral part of the cleaning pad, or can be separately adhered
to the cleaning pad. If the functional cuffs are an integral part
of the cleaning pad, the functional cuffs are preferably a looped
functional cuff formed by crimping a lower portion of the cleaning
pad, for example, in a Z-fold and/or C-fold. Alternatively, the
functional cuffs can be separately adhered to the cleaning pad via
a variety of methods known in the art including, but not limited
to, double-sided adhesive tape, heat bonding, gluing, ultrasonic
welding, stitching, high-pressure mechanical welding, and the like.
Preferably, the cleaning pad comprises two functional cuffs
situated at or near opposite edges (e.g., the leading and trailing
edges of the pad, in terms of the y-dimension) of the cleaning pad.
Preferably, the functional cuff(s) are placed in a location such
that their length is perpendicular to the back and forth mopping or
wiping direction used by the consumer.
[0078] In order to increase the resiliency of an absorbent layer
having a relatively low density, a thermoplastic material,
preferably a bicomponent fiber, is combined with the fibers of the
absorbent layer. 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 pad. In order to provide the desired resiliency, an
absorbent layer having a density of less than about 0.05 g/cm.sup.3
preferably comprises at least about 20%, preferably at least about
30%, more preferably at least about 40%, of a thermoplastic
material such as a bicomponent fiber. A preferable bicomponent
fiber comprises a copolyolefin bicomponent fiber comprising a less
than about 81% polyethylene terephthalate core and a less than
about 51% copolyolefin sheath and is commercially available from
the Hoechst Celanese Corporation under the tradename CELBOND.RTM.
T-255.
[0079] The size of the cleaning pad is determined by the cleaning
implement to which it is to be attached. Typically, however, the
cleaning pad will have dimensions in the range 100 to 300
mm.times.100 to 300 mm (expressed as
(x-dimension).times.(y-dimension)). Furthermore, the thickness of
the cleaning pad (expressed as z-dimension) is typically in the
range 1 mm to 5 mm, more preferably in the range 2 mm to 4 mm,
although again this will depend upon the application to which the
cleaning pad is to be put.
[0080] The cleaning pad may include a variety of other optional
features, including those disclosed in detail in WO-A-0027271,
which is incorporated herein by reference.
[0081] The present invention extends not only to the cleaning pads
defined in the claims, but also to cleaning pads comprising an
absorbent structure having discrete fluid reservoirs defined
therein, and any one or more of a number of optional features as
also described above, for instance a scrubbing strip; a scrubbing
layer; one or more functional cuffs; sections having different
degrees of absorbency, a density gradient; and combinations
thereof.
[0082] The cleaning pad is typically supplied to the consumer
pre-moistened with a liquid cleaning composition. Suitable liquid
cleaning compositions are well known in the art, for instance being
disclosed in WO-A-0027271 and WO-A-0123510. The cleaning pad may be
pre-moistened prior to or after formation of the fluid reservoirs,
but preferably it is pre-moistened after their formation.
[0083] The cleaning pad may be used with a variety of cleaning
implements. One example of a suitable cleaning implement is in the
form of a mop comprising a handle and a head portion (mop head),
which may be pivotally attached to the handle, for instance through
a universal joint.
[0084] The cleaning implement of the present invention may be used
to clean a variety of hard surfaces. Preferably, however, they are
used for cleaning floors. These floors may consist of ceramics,
porcelain, marble, Formica7, no-wax vinyl, linoleum, wood, quarry
tile, brick or cement, and the like.
[0085] After attachment of a cleaning pad to the cleaning
implement, cleaning is effected by wiping the head portion of the
cleaning implement across the surface to be cleaned. A preferred
wiping pattern consists of an up-and-down overlapping motion
starting in the bottom left hand (or right hand) side of the
section to be cleaned, and progressing the wiping pattern across
the floor continuing to use up-and-down wiping motions. Wiping is
then continued beginning at the top right (or left) side of the
section to be cleaned and reversing the direction of the wipe
pattern using a side-to-side motion. Another preferred wipe pattern
consists of an up-and-down wiping motion, followed by an
up-and-down wiping motion in the reverse direction. These thorough
preferred wiping patterns allow the pad to loosen and absorb more
solution, dirt and germs, and provide a better end result in doing
so by minimizing residue left behind. Another benefit of the above
wiping patterns is minimization of streaks as a result of improved
spreading of solution and the elimination of streak lines from the
edges of the pad.
[0086] Typically, after cleaning, the cleaning pad is removed and
disposed of, and with it the germs and dirt removed from the
surface, thereby promoting better hygiene and malodour control.
However, the cleaning pad may be used for multiple cleaning,
depending upon whether the pad is saturated with liquid and/or
dirt. This can be readily ascertained by the consumer.
[0087] Typically, a plurality of cleaning pads are provided in a
container or film wrapping for supply to the consumer, typically
with instructions for attachment to a cleaning implement. Kits
comprising a cleaning implement and cleaning pad are also provided,
again typically with suitable operating instructions.
[0088] The present invention is now further illustrated by
reference to the following Example and the accompanying
drawings.
[0089] FIG. 1 is a plan view of the lower surface of a cleaning pad
according to the present invention.
[0090] FIG. 2 is a cross-section taken through the cleaning pad of
FIG. 1.
[0091] FIGS. 3 and 4 are diagrammatical views of test apparatus
used for the "Performance Under Pressure" test, described
below.
[0092] With reference to FIG. 1, a cleaning pad 1 comprises a
longitudinally-extending central panel 2 comprising an upper sheet,
an absorbent core, a lower sheet. Longitudinally-extending side
panels 3 abut the central panel, and in this embodiment comprise
absorbent material of lower absorbency than the multilayer
structure of the central panel. The cleaning pad comprises a
plurality of bond lines 4 defining adjacent diamond-shaped fluid
reservoirs 5. The bond lines are discontinuous (although this is
not shown in the Figure), and define a plurality of very narrow
passages, allowing fluid communication between adjacent
reservoirs.
[0093] Referring now to FIG. 2, the reservoirs 5 can be seen to be
formed by bonding together the upper sheet 6 and the lower sheet 7,
to enclose a portion of the absorbent core 8.
EXAMPLE
[0094] Two dry Swiffer Wet.RTM. pads were bonded throughout their
thickness, one pad to comprise a plurality of adjacent
diamond-shaped reservoirs (as shown in FIG. 1), and the other pad
to have a wave pattern extending along the length of the pad, and
which does not define discrete fluid reservoirs. (The wave pattern
applied was obtained by scanning a Pledge Grab-It Wet pad). The
pads were bonded by the following ultrasonic method:
[0095] Equipment Used
[0096] 1. Branson Ultrasonic unit Model 900 BCA
[0097] 2. 9" Carbide Horn
[0098] 3. Magnesium Photo engraved patterned plate
[0099] 4. Woven Teflon
[0100] Process Conditions
[0101] 1. Amplitude is set to >50%
[0102] 2. Horn pressure is 30 psig
[0103] 3. Speed on this particular unit is set to 4 on the dial.
This gauge does not give a specified fpm.
[0104] 4. The gap between the pattern and the horn is set to zero.
A piece of woven Teflon material is placed between the horn and the
pattern to provide less friction between the two as the pattern
moves past the horn.
[0105] Steps to Make an Ultrasonically Bonded Pad
[0106] 1. Cut all materials to the desired length and width.
[0107] 2. Set-up the Ultrasonic unit to the conditions mentioned
above.
[0108] 3. Place the lower sheet of the pad centered on the
patterned plate
[0109] 4. Place the core material centered on the lower sheet
[0110] 5. Place the upper sheet of the pad centered on the core
material.
[0111] 6. Place the woven Teflon so that it covers the entire
pattern plate.
[0112] 7. Run the unit and wait until it fully retracts.
[0113] 8. Lift up the Teflon sheet and you now have an
ultrasonically welded pad.
[0114] The absorbency of each of the bonded pads and of a
non-bonded pad was determined by the following "Performance Under
Pressure" (PUP) test method. The absorbency index of the two bonded
patterns was then calculated, by dividing each of the embossed
pad's absorbency by the absorbency of the non-bonded pad. Each pad
was then loaded with squeezed out Swiffer Wet lotion, with the
non-bonded pad loaded at 6.2 g liquid/g pad and each of the bonded
pads being loaded with 6.2 g liquid/g pad multiplied by the
respective pad's absorbency index, in order to create a valid
comparison between the different pads.
[0115] Each pad was then held upright at a height of 260 mm above
the work-surface, and the time until the first drip was
measured.
[0116] The results are presented in Table 1 below.
[0117] The results show that the cleaning pad according to the
present invention had a significantly longer average drip time than
both the wave-bonded and non-bonded pads.
1TABLE 1 Average Absobent Average Pad Capacity Absorbency Index
drip time Wave Pattern 7.96 92% 14.6 Diamond Pattern* 7.43 86% 36.1
Non-bonded 8.66 100% 10.5 *The invention
[0118] Performance Under Pressure Test
[0119] This test determines the gram/gram absorption of deionized
water for a cleaning pad that is laterally confined in a
funnel/frit assembly under an initial confining pressure of 0.06
psi (about 0.6 kPa). (Depending on the composition of the cleaning
pad sample, the confining pressure can decrease slightly as the
sample absorbs water and swells during the time of the test.) The
objective of the test is to assess the ability of a cleaning pad to
absorb fluid, over a practical period of time, when the pad is
exposed to usage conditions (horizontal wicking and pressures).
[0120] The test fluid for the PUP capacity test is deionized water.
This fluid is absorbed by the cleaning pad under demand absorption
conditions at near-zero hydrostatic pressure.
[0121] A suitable apparatus 510 for this test is shown in FIG. 3.
At one end of this apparatus is a fluid reservoir 512 (such as a
petri dish) having a cover 514. Reservoir 512 rests on an
analytical balance indicated generally as 516. The other end of
apparatus 510 is a fritted funnel indicated generally as 518, a
weight assembly indicated generally as 558 that fits inside funnel
518, and cylindrical plastic fritted funnel cover indicated
generally as 522 that fits over funnel 518 and is open at the
bottom and closed at the top, the top having a pinhole. Apparatus
510 has a system for conveying fluid in either direction that
consists of sections glass capillary tubing indicated as 524 and
531a, flexible plastic tubing (e.g., 1/4 inch i.d. and 3/8 inch
o.d. Tygon tubing) indicated as 531b, stopcock assemblies 526 and
538 and Teflon connectors 548, 550 and 552 to connect glass tubing
524 and 531a and stopcock assemblies 526 and 538. Stopcock assembly
526 consists of a 3-way valve 528, glass capillary tubing 530 and
534 in the main fluid system, and a section of glass capillary
tubing 532 for replenishing reservoir 512 and forward flushing the
fritted disc in fritted funnel 518. Stopcock assembly 538 similarly
consists of a 3-way valve 540, glass capillary tubing 542 and 546
in the main fluid line, and a section of glass capillary tubing 544
that acts as a drain for the system.
[0122] Referring to FIG. 4, assembly 558 consists of a weight that
fits inside funnel 518. The cleaning pad sample indicated generally
as 560 rests in funnel 518 with the surface-contacting layer in
contact with glass frit in 518. The cleaning pad sample is a
circular sample having a diameter of 5.4 cm. While sample 560 is
depicted as a single layer, the sample will actually consist of a
circular sample having all layers contained by the pad from which
the sample is cut. Cylindrical stainless steel weight 558 is fitted
with a handle on the top (not shown) for ease in removing. The
weight of steel weight 558 is 63.2 g, which corresponds to a
pressure of 0.06 psi for an area of 16.0 cm.sup.2.
[0123] The components of apparatus 510 are sized such that the flow
rate of deionized water therethrough, under a 10 cm hydrostatic
head, is at least 0.01 g/cm.sup.2/sec, where the flow rate is
normalized by the area of fritted funnel 518. Factors particularly
impactful on flow rate are the permeability of the fritted disc in
fritted funnel 518 and the inner diameters of glass tubing 524,
530, 534, 542, 546 and 531a, and stopcock valves 528 and 540.
[0124] Reservoir 512 is positioned on an analytical balance 516
that is accurate to at least 0.01 g with a drift of less than 0.1
g/hr. The balance is preferably interfaced to a computer with
software that can (i) monitor balance weight change at pre-set time
intervals from the initiation of the PUP test and (ii) be set to
auto initiate on a weight change of 0.01-0.05 g, depending on
balance sensitivity. Capillary tubing 524 entering the reservoir
512 should not contact either the bottom thereof or cover 514. The
volume of fluid (not shown) in reservoir 512 should be sufficient
such that air is not drawn into capillary tubing 524 during the
measurement. The fluid level in reservoir 512, at the initiation of
the measurement, should be approximately 2 mm below the top surface
of fritted disc in fritted funnel 518. This can be confirmed by
placing a small drop of fluid on the fritted disc and
gravimetrically monitoring its slow flow back into reservoir 512.
This level should not change significantly when weight assembly 558
is positioned within funnel 518. The reservoir should have a
sufficiently large diameter (e.g., about 14 cm) so that withdrawal
of about 40 ml portions results in a change in the fluid height of
less than 3 mm.
[0125] Prior to measurement, the assembly is filled with deionized
water. The fritted disc in fritted funnel 518 is forward flushed so
that it is filled with fresh deionized water. To the extent
possible, air bubbles are removed from the bottom surface of the
fritted disc and the system that connects the funnel to the
reservoir. The following procedures are carried out by sequential
operation of the 3-way stopcocks:
[0126] 1. Excess fluid on the upper surface of the fritted disc is
removed (e.g. poured) from fritted funnel 518.
[0127] 2. The solution height/weight of reservoir 512 is adjusted
to the proper level/value.
[0128] 3. Fritted funnel 518 is positioned at the correct height
relative to reservoir 512.
[0129] 4. Fritted funnel 518 is then covered with fritted funnel
cover 522.
[0130] 5. The reservoir 512 and fritted funnel 518 are equilibrated
with valves 528 and 540 of stopcock assemblies 526 and 538 in the
open connecting position.
[0131] 6. Valves 528 and 540 are then closed.
[0132] 7. Valve 540 is then turned so that the funnel is open to
the drain tube 544.
[0133] 8. The system is allowed to equilibrate in this position for
5 minutes.
[0134] 9. Valve 540 is then returned to its closed position.
[0135] Steps Nos. 7-9 temporarily "dry" the surface of fritted
funnel 518 by exposing it to a small hydrostatic suction of about 5
cm. This suction is applied if the open end of tube 544 extends
about 5 cm below the level of the fritted disc in fritted funnel
518 and is filled with deionized water. Typically about 0.04 g of
fluid is drained from the system during this procedure. This
procedure prevents premature absorption of deionized water when
weight 558 and sample 560 assembly is positioned within fritted
funnel 518. The quantity of fluid that drains from the fritted
funnel in this procedure (referred to as the fritted funnel
correction weight, or "Wffc") is measured by conducting the PUP
test (see below) for a time period of 20 minutes without
sample/weight assembly 558 and 560. Essentially all of the fluid
drained from the fritted funnel by this procedure is very quickly
reabsorbed by the funnel when the test is initiated. Thus, it is
necessary to subtract this correction weight from weights of fluid
removed from the reservoir during the PUP test (see below).
[0136] A round die-cut sample 560 is placed in funnel 518. The
weight 558 is placed onto sample 560, and the top of funnel 518 is
then covered with fritted funnel cover 522. After the balance
reading is checked for stability, the test is initiated by opening
valves 528 and 540 so as to connect funnel 518 and reservoir 512.
With auto initiation, data collection commences immediately, as
funnel 518 begins to reabsorb fluid.
[0137] Data is recorded at intervals over a total time period of
1200 seconds (20 minutes). PUP absorbent capacity is determined as
follows:
t.sub.1200 absorbent capacity
(g/g)=[Wr.sub.(t=0)-Wr.sub.(t=1200)-Wffc]/Wd- s
[0138] where t.sub.1200 absorbent capacity is the g/g capacity of
the pad after 1200 seconds, Wr.sub.(t=0) is the weight in grams of
reservoir 512 prior to initiation, Wr.sub.(t=1200) is the weight in
grams of reservoir 512 at 1200 seconds after initiation, Wffc is
the fritted funnel correction weight and Wds is the dry weight of
the cleaning pad sample.
[0139] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention.
[0140] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *