CA2266541C - A cleaning implement - Google Patents

Abstract

A cleaning implement comprising a handle (Fig. 1a) and a removable cleaning pad (200). The cleaning pad exhibits the ability to initially delay absorption of cleaning fluid, soil and the like, but then absorb those materials after this initial delay.

Description

A CLEANING IMPLEMENT
TECHNICAL FIELD
This application relates to a cleaning implement useful in removing soils from hard surfaces. The application particularly relates to a cleaning implement comprising a handle and a removable absorbent cleaning pad. The application also relates to the absorbent cleaning pad that is useful with the cleaning implement. The cleaning pad exhibits the ability to absorb and retain significant fluid levels, but after an initial delay in fluid uptake.
BACKGROUND OF THE INVENTION
The literature is replete with products capable of cleaning hard surfaces such as ceramic tile floors, hardwood floors, counter tops and the like. In the context of cleaning floors, numerous devices are described comprising a handle and some means for absorbing a fluid cleaning composition. Such devices include those that 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, etc., residues. These mops therefore require the use of a separate container to perform the rinsing step(s), and typically these rinsing steps fail to sufficiently remove dirt residues. This may 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.
To alleviate some of the negative attributes associated with reusable mops, attempts have been made to provide mops having disposable cleaning pads. For example, U.S.
Patent No. 5,094,559, issued March 10, 1992 to Rivera et al., describes a mop that includes a disposable cleaning pad comprising a scrubber layer for removing soil from a soiled surface, a blotter layer to absorb fluid after the cleaning process, and a liquid impervious layer positioned between the scrubber and blotter layer. The pad further contains a rupturable packet means positioned between the scrubber layer and the liquid impervious layer. The rupturable packets are so located such that upon rupture, fluid is directed onto the surface to be cleaned. During the cleaning action with the scrubber layer, the impervious sheet prevents fluid from moving to the absorbent blotter layer.
After the cleaning action is completed, the pad is removed from the mop handle and reattached such that the blotter layer contacts the floor. While this device may alleviate the need to use

-2-multiple rinsing steps, it does require that the user physically handle the pad and reattach a soiled, damp pad in order to complete the cleaning process.
Similarly, U.S. Patent 5,419,015, issued May 30, 1995 to Garcia, describes a mop having removable, washable work pads. The pad is described as comprising an upper layer which is capable of attaching to hooks on a mop head, a central layer of synthetic plastic microporous foam, and a lower layer for contacting a surface during the cleaning operation.
The lower layer's composition is stated to depend on the end-use of the device, i.e., washing, polishing or scrubbing. While the reference addresses the problems associated with mops that require rinsing during use, the patent fails to provide a cleaning implement that sufficiently removes the soil that is deposited on typical household hard surfaces, in particular floors, such that the surface is perceived as essentially free of soil.
In particular, the synthetic foam described by Garcia for absorbing the cleaning solution has a relatively low absorbent capacity for water and water-based solutions. As such, the user must either use small amounts of cleaning solution so as to remain within the absorbent capacity of the pad, or the user must leave a significant amount of cleaning solution on the surface being cleaned. In either situation, the overall performance of the cleaning pad is not optimal.
While many known devices for cleaning hard surfaces are successful at removing a vast majority of the soil encountered by the typical consumer during the cleaning process, they are inconvenient in that they require one or more cleaning steps. The prior art devices that have addressed the issue of convenience typically do so at the cost of cleaning performance. As such, there remains a need for a device that offers both convenience and beneficial soil removal. Therefore, it is an object of the present invention to provide a cleaning implement that comprises a removable cleaning pad, which alleviates the need to rinse the pad during use. In particular, it is an object of the present invention to provide an implement that comprises a removable cleaning pad with sufficient absorbent capacity, on a gram of absorbed fluid per gram of cleaning pad basis, that allows the cleaning of a large area, such as that of the typical hard surface floor (e.g., 80-100 ft2), without the need to change the pad. It is a further object to provide such a cleaning implement where the pad offers beneficial soil removal properties. Where the cleaning implement of the present invention is used in combination with a cleaning solution, it is a further object to provide a substantially dry end result.
SUMMARY OF THE INVENTION
The present invention relates to a cleaning implement comprising:
a. a handle; and b. a removable cleaning pad comprising:

3 PCT/US97/15962 i. a scrubbing layer; and ii. an absorbent layer;
wherein the cleaning pad has a t30 percent absorbency of not more than about 10% of the pad's 11200 absorbent capacity, and a t1200 absorbent capacity of at least about S g of deionized water per g of the cleaning pad.
Depending on the means used for attaching the cleaning pad to the cleaning implement's handle, it may be preferable for the cleaning pad to further comprise a distinct attachment layer. In this embodiment, the absorbent layer would be positioned between the scrubbing layer and the attachment layer.
While not limited to wet cleaning applications, the present invention is preferably used in combination with a cleaning solution. That is, while the implement initially exists in a dry state, optimal cleaning performance for typical hard surface cleaning will involve the use of a cleaning fluid that is applied to the soiled surface prior to cleaning with the present implement. During the effort to develop the present cleaning implement, Applicants discovered that, surprisingly, a critical aspect of cleaning performance is the avoidance of initial, rapid fluid uptake. That is, while it is important to absorb essentially all of the fluid cleaning solution during the time in which a typical user will clean a surface, it is also important to avoid immediate absorption by the cleaning pad. This is generally counter to the teachings of the prior art pertaining to absorbent articles, where it is accepted that immediate, rapid absorbency is desired.
While not wishing to be bound by theory, it is believed that initially avoiding absorbence by the cleaning pad allows the pad to thoroughly spread the solution on the surface, thereby enhancing fluid-soil contact. Further, the controlled delay in absorbence exhibited by the pads of the present invention allows sufficient contact time for the cleaning solution to interact with and remove soil. After this initial delay, fluid and soil are then rapidly absorbed to leave a clean, dry surface. In this respect, a minimal overall absorbency is a requisite of the cleaning pad. This overall absorbency is also important, as it allows for the use of sufficient quantities of cleaning solution (to maximize solution-soil interaction) and ensures that essentially ail of the solution and solubilized soil is removed from the surface.
The implement of the present invention is designed to be compatible with all hard surface substrates, including wood, vinyl, linoleum, no wax floors, ceramic, Formica~, porcelain, glass, wall board, and the like.
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a perspective view of a cleaning implement of the present invention which has an on-board fluid dispensing device.

-4-Figure la is a perspective view of a cleaning implement of the present invention which does not have an on-board fluid dispensing device.
Figure 1 b is a side view of the handle grip of the implement shown in Figure I a.
Figure 2 is a perspective view of a removable cleaning pad of the present invention.
Figure 3 is a blown perspective view of the absorbent layer of a removable cleaning pad of the present invention.
Figure 4 is a cross-sectional view of one embodiment of a removable cleaning pad of the present invention.
Figure 5 represents a schematic view of an apparatus for measuring the Performance Under Pressure (PUP) capacity of the removable cleaning pad.
Figure 6 represents an enlarged sectional view of the piston/cylinder assembly shown in Figure 5.
Figure 7 represents a blown perspective view of another removable cleaning pad of the present invention.
Figure 8 represents a perspective view of another removable cleaning pad of the present invention.
DETAILED DESCRIPTION
I. ' Definitions As used herein, the term "comprising" means that the various components, ingredients, or steps, can be conjointly employed in practicing the present invention.
Accordingly, the term "comprising" encompasses the more restrictive terms "consisting essentially of and "consisting of."
As used herein, the term "direct fluid communication" means that fluid can transfer readily between two cleaning pad components or layers (e.g., the scrubbing layer and the absorbent layer) without substantial accumulation, transport, or restriction by an interposed layer. For example, tissues, nonwoven webs, construction adhesives, and the like may be present between the two distinct components while maintaining "direct fluid communication", as long as they do not substantially impede or restrict fluid as it passes from one component or layer to another.
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 usually corresponds to the thickness of the cleaning pad or a pad component including scrim material.
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 usually correspond to the length and width, respectively, of the cleaning pad or a pad component.

,_ As used herein, the term "layer" refers to a nrenrber or component of a cleaning pad whose primary dimension is :~-Y, :,.e., along its ltugtlr and w width, It should be understood that the germ layer is not we:cessaril~~~ limi~:~ci to ;~irr~;lir I,.rytrs or ~lrer~ts c,~l material. Tlrus the Dryer can comprise laminates or eornbiraatioras of several ;sheets or verbs iaf tl~e requisite type of materials.
Accordingly, the term "layer-' includes the terms "layers'" rnd "layered".
As used herein, the term "hydrophilic" is used tc:w refer to surfaces that are wettable by aqueous fluids deposited thereon. l lydrcphilii:ily and vvr.°tlabilit ~
are typically defined in Corms of contact angle and the surface: tension of the tlt.rids and solid surfaces involved, hhis is discussed in detail in the American ('.lremical Society pulalicatiirn entitled (_'ontact Angle; Wettabili and :Adhesion edited by Robert I=. Goulil (l'«pr riglri l ~l(,4). A surtace is said to be wetted by a fluid ti.e., hydrophilic) when either the contact angle laftwecra the tlukd arncj the surface is less than 90°, or when the fluid tends to spread s,pontanc~rrr;ly aeros,> the ~urlW
c°, both conditions normally co-existing. Conversely, a surface is considered to be "hycfrcrphobic" if the contact angle is greater than 90" and the fluid does not spread spontaneously acrirss tire wrrface.
As used herein, the term "sccrim'' means zany dural7le material drat provides texture; to the surface-cont:acfing side c:rf the cleaning pad's st;rubbinfla~ri:.r~, arid also has a sufficient degree of openness to allow the requisite movement of fluid tcx Chi: ahsorhent layer of the cleaning pad.
Suitable materials include material, that have a continuous, open structure, such as synthetic and wire mesh screens. The opera areas o't' these nratiruals may he rrradi'ly controlled by varying the number of interconnected strands ~,lt.at compr~i:~c: the ro~esh, by v.:coratrolling the thickness iaf those interconnected strands, etc. ()they suitable materials include those where texture is provided by a discontinuous pattern printed on a substrate. In this aspect, a durable material (e.g., a synthetic) raaay be printed on a substrate in a continuous i:rr discoratisauou';
laattorn, such as individual dots and/or lines, to provide the requisite t~xturo. Similarly, tlrc: corntirruous or discar~tinuous pattern may printed onto a release material that wlill theca act as the: ~cr-im.
'Chose fratterns may be repeating or they may be random. It will be understood that one or more of the approaches described t<or providing tho desired tr:xture rrny° k~m cc'atxRbin~il to form tkae optional scrim material.
'1"he Z direction height and ohren area irf thr scrim and or si~rutabin~
substrate layirr help to control and or retard the flow of liquid into the absorbent core n~.a~.erial. 'fhe 7 height of the scrim and or scrubbing substrate help provide a means c?f controlling the volume of' liquid in contact with the cleaning surface while at l:he sr~rne time cc°>ntr~olling tire rati° of' liquid absorption, fluid communication into the absorption cirre material.
For purposes of the present irlventii>n, an "upper" layer a:at a cleaning pad is a layer- that is relatively further away from the surface that is to be i;leaned (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 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). As such, the scrubbing layer is the lower-most layer and the absorbent layer is an upper layer relative to the scrubber layer. The terms "upper" and "lower" are similarly used when referring to layers that are multi-ply (e.g., when the scrubbing layer is a two-ply material).
All percentages, ratios and proportions used herein are by weight unless otherwise specified.
II. Cleaning Implements The cleaning implement of the present invention comprises:
a. a handle that preferably comprises at one end a pivotably attached support head; and b. a removable cleaning pad comprising:
i. a scrubbing layer;
ii. an absorbent layer which is preferably in direct fluid communication with the scrubbing layer; and iii. an optional attachment layer for releasably attaching the cleaning pad to the handle, preferably to the optional support head;
wherein the cleaning pad has a t30 percent absorbency of not more than about 10% of the pad's t 1200 absorbent capac ity, and a t 1200 absorbent capacity of at least about 5 g of deionized water per g of the cleaning pad.
As indicated above, Applicants' discovery is based on the finding that an initial delay in fluid uptake by the absorbent pad improves overall cleaning performance. In particular, the cleaning pads have a percent absorbency, based on the t 1200 absorbent capacity of the pad, at thirty (30) seconds measured under a confining pressure of 0.09 psi (hereafter referred to "t30 percent absorbency") of not more than about 10%.
Preferably the t30 percent absorbency will be not more than about S%, more preferably not more than about 2%, still more preferably not more than about I%.
While avoiding rapid initial fluid uptake by the pad is desirable, it is still necessary for the cleaning pad to absorb a majority of the fluid used during the cleaning process. As such, the cleaning pads will have an absorbent capacity at 1200 seconds, when measured under a confining pressure of .09 psi (hereafter referred to as "t1200 absorbent capacity") of at least about S g deionized water per g of the cleaning pad. Preferably the cleaning pad will have a t1200 absorbent capacity of at least about 10 g/g, more preferably at least about 20 g/g, and still more preferably at least about ~U gig. I'I~e cleaning pad will preferably have a too of at least about 10 g/g, more preferak~ly sr tu,,,~, u>t at least r~'hornt 20 g/g.
Values for t~« perc.~nt ab;yc:>rbencv rind t,A~",~ acrd t~,~,~, ~rbsorbent capacity are measured by the performance under pr-essur~c~ (refer°red tc.~ Ire rein as "PIJI'"j method, which is described in detail in the Test Methods section below. Briefly, the PI.IP method measures a cleaning pad's absorbency at different times under an initial confining pressure of 0.09 psi (which reflects typical in-use pressures during the cleaning operation 1.
~1'ht cleaning pads will preferablYv, but not nec:essar°ily, have a total fluid capacity (of deionized water) of at least about 100 g, more pref~;rsrb'ly at bast about 200 g, still more preferably trt least about '300 g and mast pr~,fer~ably at Ic~rrsl alac>ut 400 g. While pads having a total fluid capacity 'less tlrare 1()0 g are within the scope of tkr~
invention, they are not as well suited for cleaning large arc;as, such as seen irr ~t t~~~ic;al hcnusehold, as are higher capacity pads.
The skilled artisan will recognize that various materials may be utilized to carry out the claimed invention. Thus, while preferred materials are described below for the various implement and cleaning pad components, it is r~ecagr~i~~ed drat the scope of the invention is riot limited to such disclosures.
A. Handle The handle of the cleaning implerrrerrt will be any material that will facilitate gripping of the cleaning implement. 'fhe handle c~f the cleaning implement will preferably comprise any elongated, durable material that will provide practical cleaning. The length of the handle will be dictated by the end-use of the implement.
The handle will preferably comprise at one end a support head to which the cleaning pad can be releasably attached. 'l o facilitate ease of use, the: support head can be pivotably attached to the handle using known joint assemblies. Any suitable means f~~>r attaching the cleaning pad to the support lr~,ad may be rrtiliaed, so Icrng as the cleaning pad remains affixed during the cleaning process. Examples of suitable; fastening rr~eans include clamps, hooks &
loops (e.g.~ Velcroc~~), and the like. In a preferred mnbo~iiment, the support head will comprise hooks on its lower surface that will mechanically attach to the upper layer (preferably a distinct attachment layer of the absorbent cleaning padj.
A preferred handle, ~ornprisirrg a fluid dispensing mc:.ans, is depicted in Figure 1 and is fully described in U.S, Patent ~Jo. 5,888,OO~i~. Another- puetirrr~ed Dandle, which does not contain a fluid dispensing means, is dc;pictc;d irr I~igs. I~r ~:arrd lla, <znd is fully described in PCT
Publication No. WO 98i 1204'.3.

_g_ B. Removable Cleaning Pad In light of Applicants' discovery that controlled absorbency plays an important role in the cleaning performance of the implements of the present invention, the skilled artisan will recognize that the rate of fluid absorption, and in particular the initial delay in rapid fluid uptake, of the cleaning solution by the cleaning pad is dictated by the materials of the pad. In this regard, volume flux (i.e., rate of fluid uptake) may be calculated using the Hagen-Poiseuille law for laminar flow. The Hagen-Poiseuille law provides that volume flux, q, is calculated according to the following formula:
q ° R2((2ycos6/R)-pgLl~8L~
where R is the tube radius, y is the surface tension of the fluid being absorbed, A is the contact angle at the fluid-solid interface, p is the density of the fluid, g is the gravitational constant, L is the wetted length of the tube, and p is the viscosity of the fluid. From this equation, it is evident that the rate of absorbency by the cleaning pad is controllable by, for example, adjusting the pore size of the material constituting the cleaning pad, adjusting the surface wettability (cosh) of the material for the absorbed fluid, etc.
Together with the teachings of the present disclosure, any of the well known absorbent materials may be utilized and combined to achieve the desired initial delay in absorbency, but overall absbrbent capacity. Accordingly, while representative materials and embodiments useful as the cleaning pad are described below, the invention is not limited to such materials and embodiments.
l. Scrubbing Layer The scrubbing layer is the portion of the cleaning pad that contacts the soiled surface during cleaning. As such, materials useful as the scrubbing layer must be sufficiently durable that the layer will retain its integrity during the cleaning process. In addition, when the cleaning pad is used in combination with a solution, the scrubbing layer must be capable of absorbing liquids and soils, and relinquishing those liquids and soils to the absorbent layer. This will ensure that the scrubbing layer will continually be able to remove additional material from the surface being cleaned. Whether the implement is used with a cleaning solution (i.e., in the wet state) or without cleaning solution (i.e., in the dry state), the scrubbing layer will, in addition to removing particulate matter, facilitate other functions, such as polishing, dusting, and buffing the surface being cleaned.
The scrubbing layer can be a monolayer, or a multi-layer structure one or more of whose layers may be slitted to facilitate the scrubbing of the soiled surface and the uptake of particulate matter. This scrubbing layer, as it passes over the soiled surface, interacts with the soil (and cleaning solution when used), loosening and emulsifying tough soils and permitting them to pass freely into the absorbent layer of the pad. The scrubbing layer preferably contains openings (e.g., slits) that provide an easy avenue for larger particulate soil to move freely in and become entrapped within tire absorbent layer of the pad. Low density structures are preferred for use as the scrubbing Layer, to facilitate transport of particulate matter to the pad's absorbent layer.
In order to provide desired integrity, materials particularly suitable for the scrubbing layer include synthetics such as polyolefins (e.g., polyethylene and polypropylene), polyesters, polyamides, synthetic cellulosics (e.g., Rayon~), and blends thereof. Such synthetic materials may be manufactured using known process such as carded, spunbond, meltblown, airlaid, needlepunched and the like.
ii. Absorbent Layer The absorbent layer serves to retain any fluid and soil absorbed by the cleaning pad during use. While the scrubbing layer has some affect on the pad's ability to provide an initial delay in fluid absorbence, the absorbent layer plays the major role in achieving the desired initial delay and overall absorbency of the present invention.
The absorbent layer will be capable of removing fluid and soil from the scrubbing layer so that the scrubbing layer will have capacity to continually remove soil from the surface. The absorbent layer also should be capable of retaining absorbed material under typical in-use pressures to avoid "squeeze-out" of absorbed soil, cleaning solution, etc.
The absorbent layer will comprise any material that is capable of absorbing and retaining fluid during use, but after an initial period during which minimal fluid is absorbed. To achieve desired total fluid capacities, it will be preferred to include in the absorbent layer a material having a relatively high capacity (in tenors 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 I S
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.
Representative superabsorbent materials include water insoluble, water-swellable superabsorbent gelling polymers (referred to herein as "superabsorbent gelling polymers") which are well known in the literature. These materials demonstrate very high absorbent capacities for water. The superabsorbent gelling polymers useful in the present invention can have a size, shape and/or morphology varying over a wide range. These polymers can be in the form of particles that do not have a large ratio of greatest dimension to smallest dimension (e.g., granules, flakes, pulveruients, interparticle aggregates, interparticle crosslinked aggregates, and the like) or they can be in the form of fibers, sheets, films, foams, laminates, and the like. The use of superabsorbent gelling polymers in fibrous form provides the benefit of providing enhanced retention of the superabsorbent material, -1U_ relative to particles, during the clearving prcou~as. W hilo their c<rpauiCy is geruerally lower for aqueous-based mixtures, these materials still demonstrate significant absorbent capacity for such mixtures. The patent literature is replete wvith disclosures ot~ water-swellable materials. See, for example, 1J.S. Patent 3,699,103 (I-larper et al.), issuec:l June 1.3, 197'?:
U.S. Patent 3,770,731 (Harmony, issued June :20, 1~~72; t,J.S. Reissucv latent 3~,64~7 il3randt et al..), reissued April 19, 1989; U.S. Patent 4,834,735 {Alemany et al.), issued May 3t1, 198<>.
Superabsorbent gelling polymers usc:lul in tlr~ present invention include a variety of water-insoluble, but water-swellable laolyrrners ~alral>le cqf absorbing large quantities of fluids.
Such polymeric materials ad-e also commonly roferred t~~ as "hydrocolloids'', and can include polysaccharides such as carboxymethyl starch, carboxymethyl eellutose, and hydroxypropyl i;ellulose, nonionic types suclr as yolyw~inyl alcohol, acrd l~rrlyvinyl ether~s; oatiob~ie types such as polyvinyl pyridine, polyvinyl nrorphulirritarro, ~rn~.l 1'~f,l'~(-dirnethylaminoethyl or N,N-diethylaminopropyl acrylates and methacrylates, and the rcapec;tive quaternary salts thereof.
Typically, superabsorbent gelling polymers useful in the present invention have a multiplicity of anionic functional groups, such as sullonic acid, and nnor~: typically carboxy, groups. Examples of polymers suitable for u~e~: heroin incl~zd~ thoso. ~~~Irieia ace prepared from polymerizable, unsaturated, acid-containing monomers. Thus, such monumers include the olefinically unsaturated acids and anhydrides that contain tat least c>nc carbcln to carbon olefinic double bond.
More specifically, these monomers can be selected horn oVefini~:ally unsaturated carboxylic acids and acid anhydrides, olefinically unsatt.~rated sulfi>n~c acids, and mixtures tht;reof~.
Some non-acid monomers can also be included, usually in minor amounts, in preparing the superabsorbent gelling pol~nners r.iso.ti~l horoioa. Such omn-acid nrononrers can include, for example, the water-soluble or water-dislaersiblo estors ui~ the auicl-containing mc.anorners, as well as monomers that contain no carboxylic c>r scrlfonic acid grcwrps at all.
Optional non-acid monomers can thus include monomers cerntaining the following types of functional groups:
carboxylic acid or sulfc~nic acid esters, hydroxyl grcruh:~, anode;-groups, amino groups, nitrile groups,, quaternary ammoniurrr salt groups, aryl groups tc.g., phenyl g,~-oups, such as those derived from styrene monomer-). These non-acid monomers are well-known materials and are described in greater detail, for example, ira U.S. Patent :~,07Ci,6fi3 (I'vlasuda ca al.), issued February 28, 197$, and in U.S. Patent 4,062,81 7 ~ Westc;rman), issued 1_~c:i;vnnb~'.vr 13, 1 ~~77.
Olefinically unsaturated carboxylic acid and carboxylic acid anhydride monomers include the acrylic acids typified by acrylic acid itsell; tnetlracrylic acid, ethacrylic acid, a-chloroacrylic acid, a-cyanoacrylic. ~r~;id, ~i-.rnethylac;rylic: acid ~crotonic acid), a-phenylacrylic acid, (3-acryloxypropionic acid, surbic acid, ~xwhk>rusorbic acid, angelic acid"

y _ cinnamic acid, p-chlorocinnamic acid, ~3-stc:rylacrylic acid. itaconic acid, citroconic acid, mesaconic acid, glutacanic acid, ai:onitic: acid, malefic:. acid, turnaric acid, tricarboxyethylene and rnaleic acid anhydride.
C~lefinically unsaturated sulfc~rric acica monarrrers include aliphatic or aromatic vinyl sulfonic acids such as vinylsulfonic acid, ally) sulfonic acid, vinyl toluene svrlfonie acid and styrene sulfonic acid; acrylic and methacrylic sulfimic acid aucla as sulfbethyl acrylate, sulfoethyl methaerylate, sulfopropyl ac~rylate, sulfc:rl,7ropyl rnetl"tacr~rlato., 2-hydra~xy-3-methacryloxypropyl sulfonic acid and 2-acrylamide-2-nuethylprc>parte sullcoraic acid.
Preferred superabsorbent gelling polymers t~-~r cnse in the present invention contain carboxy groups. 'these polymers include hydrolyzed starch-acrylonitrile graft copolymers, partially neutralized hydrolysed starch-acrylonitt-ile ~,~r;,~f'c t;e~pt:olymers, starch-acrylic acid graft copolymers, partially neutralized starch-acrylic acid graft captrly~rrers, saponified vinyl aeetate-acrylic ester copolymers, hydroly~:ed acrylonitrile or acrytamide copolymers, slightly network crosslinked polymers of any of the laregoing copotytrrers, partially neutralized polyacrylic acid, and slightly network crosslinked polymers 1:r1' par-tialdy neutralized polyacrvlic acid. These polymers can be used either ~c:rlely c.~r in the 1'carm of a mixture: of two or more different polymers.
Examples of these polymer materials are disclosed in L.%-S. Patent 3,661,875, U.S, Patent 4,076,663, U.S. Patent 4,03,776, LI.S. Patent 4,666,~~8:3 ar~sd L.S. Patent 4,734,~;~8.
Most preferred polymer materials for use in rnakirug the; suloerabsorbent gelling polymers are slightly network crasslinked polymers of partially ~~~rutralizeKl polyacrylic :aids and starch derivatives thereof. Most preferably. the hydrogel-forming absorbent polymers comprise from about 50 to about 95°i°, prafsrably abcaut '7".~".a,, nuutrali~ec9, slightly netvvcrrk crosslinked, polyacrylic acid (i.e. poly (sodium acrylateiacrvylic acid)). Netwc7rk crosslin>,;ing renders the polymer substantially water-insoluble ancl, itt part, dcaermines the absorpti~,~e capacity and extractable polymer content c.haracteristies oi' the superabsorbent gelling polymers. Processes for network crosslinking then: pca'lymfrrs zcnd ~ylaiu4al n ~twork ~ros;;linking agemts are described in LJ.S. Patent 4,076,663.
While the superabsorbent gelling polymers is preferably of one type (i.e., homogeneous), mixtures of polymers can also be used in the implement; of the present invention. For example, mixtures of starch-acrylic acid graft ccthalym~rs and slightly r~ttwork cros,slinlced polymers of partially neutralized polyacrylic acid can be used in the pr~e,trat irrvtentic~n.
While any of the superabsorbent gelling polymers described in the prior art may be useful in the present invention, it has recently been recognized that where significant levels (e.g., more than about ~0°ro by weight o1~ the absorbent structure) of supers:cbsorbent gelling polymers are to be included in an absorbent strrrctur~, and in particular w~hcrc one: or more _1 regions of the absorbent; layer will comprise me>re than alac.aut -i1)'%,, by weight r:af the region, the problem of gel blocking by the swollen particles may impede fluid flow and thereby adversely affect the ability of the gelling pol,yrrmrs to ahsc>rb to tlr~~r .ful'I
capacity in the ~~.lesired period of time. L1.S. Patent 5,147,343 {K.ellenbc;rger ca al,:), issuc,:d September 15, 1992 and U.S. Patent

5,149,335 {Kellenbergcr et al.;), iswcd Septcniber 22, I992, describe superabsocbent gelling polymers in terms of their Absorberrcy Under l..,oacl (At.,IL ), w~lr~ne~
gelling polymers absorb fluid (U.9% saline) under a confining pressure of U.m~ psi. l he methods for detenW
ning AUL are described in these patenta. Polymers dc~sarik~ecl therein rrray be particularly useful in embodiments c>f the present invention that contain regions of relatively high levels of superabsorbent gelling polymers. In particular, where high conc.entratiorns c>f sup~~rabsi~rbent gel'li~yg polymer are incorporated in the cleanings pad, thoso polymers 4vi11 prefeavably have an AUL, measured according to the methods described in L.J.'i. Patent 5,147,x43, of at least about 24 ml/g. more preferably at least about 27 mlig after 1 hour; c7r an Al.)1., measured according to the methods described in U.S. Patent 5,149,335, of at least about 1S n~l/g, rraoro preferably ;at least about 1~8 ml/g after 15 minutes. L).S. Patent Los. 5,599,335 and S.Ei50,~22 also address the problem of gel blocking and describe superabsorbent gelling polymers useful irr overcoming this phenomena.
rl°hese applications speuific~rlly descr°ibe sciperabsor'kaent gelling polymers ~rhich avoid gel blocking at even higher confining pressures, specifically 0.7 psi. In the embodiments of the present invention where the absc>ri~ont layer wi&I ~;<»~tairr regic.9ns comlorising high levels (e.g., more than about 50~~, by weight c>f the regions of sr.rperabsorbent gelling polymer, it may be preferred that the supcrabsorbent gEllinl; I>ol,yrnc:r be as described rn the aforementioned applications by Goldman et al.
Other usetul superbscrrbent rnat:erials include hydrc>phihc polymeric toanrs, such as those described in U.S. Patent No. 5,650,2'?' and U.S. Patent hlo. 5,3~7,2t)7 (Dyer et al.), issued February 7, 1995. These references describe polymeric, hydrophilic absorbent foams that are obtained by polymerizing a luigh ir~t~rrral phase water-in-cril emulsion (commonly referred to as HlPEs). These foams are readily tailored to provide varying physical properties (pore size, capillary suction, density, etc.) that affect fluid handling ability. As such, these materials are particularly useful, either alone or in combination with other such foams or with fibrous structures, in providing the overall capacity rec)uired by t'tm present invention.

Where superabsorbent material is included in the absorbent layer, the absorbent layer will preferably comprise at least about 15%, by weight of the absorbent layer, more preferably at least about 20%, still more preferably at least about 25%, of the superabsorbent material.
The absorbent layer may also consist of or comprise 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, polytetrafluoroethyiene, polyvinylidene chloride, polyacrylics such as ORLON~, polyvinyl acetate, Rayon~, polyethylvinyl acetate, non-soluble or soluble polyvinyl alcohol, polyolefins such as polyethylene (e.g., PULPEX~) and polypropylene, poiyamides such as nylon, polyesters such as DACRON~ or KODEL~, polyurethanes, polystyrenes, and the like. The absorbent layer 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 botlf hydrophilic and hydrophobic fibers. As indicated above, the particular selection of hydrophilic or hydrophobic fibers will depend upon the other materials included in the absorbent (and to some degree the scrubbing) layer. 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~). 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.
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.
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"

-l4-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.
Where fibers are used as the absorbent layer (or a constituent component thereof), the fibers may 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 interfber 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 may be beneficial in providing additional overall integrity to the cleaning pad.
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 celiulosic 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.
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 190°C, and preferably between about 75°C and about 175°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°C.

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~) 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 chtoride/vinyi acetate, and the like. Depending upon the desired characteristics for the resulting thermally bonded absorbent member, 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 thenmoplastic 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~ 76 manufactured by ICI Americas, Inc. of Wilmington, Delaware, and various surfactants sold under the Pegosperse~
trademark by Glyco Chemical, Inc. of Greenwich, Connecticut. 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.
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.
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, polyethylviny) acetate or polyethylene sheath (e.g., those available from Danaklon a/s, Chisso Corp., and CELBOND~, available from Hercules). These bicomponent fibers can be concentric or eccentric. As used herein, the terms "concentric"

-t6-and "eccentric" refer to whether tlae ~l~~~xtlz has ~:v thickness that is even, or uneven, through the cross-sectional area of the bicot~apcanerat fiber°.
1_;ccentric biccamponent fibers can be desirable in providing more comlxressive strength at lower fiber thic:knesses.
Methods far preparing thermally bonded fibrous materials are described in co-pending L:1.S. Patent No. 5,607,~1~ and t.).S. Patent 5,5~~9.,~89 (Homey et al.), issued August 27, 1996 (see especially Columns 9 to 1t)).
The absorbent layer tray also comprise a HIPS-derived hydrophilic, polymeric foam that does not have the high absorbency of those described above as ''superabsorbent materials". Such foarr~s and methods for their preparatian are described in U.S. Patent 5,550,167 (DesMarais), issued August ~.' 7, 19!)6; and 11.5.1'atont No.
5,563,179.
The absorbent layer of tlxe cleaning pad nay be comprised of a homogeneous material, such as a blend of cellulosic fube~°s (;opticmally thermally bonded> and swellable superabsorbent gelling polymer. Alternatively, the absorbent layer may be comprised of~
discrete layers of material, such as a layer ofY lla~rrraally bonc~led airlaid material and a discrete layer of a superabsorbent material. For example, a thernmlly banded layer of cellulosic fibers can be located lower thorn (i.e., beneat:hj the superabsorbent material (i.e., between the superabsorbent mai:erial atad the scrubbing layer). In order to achieve high absorptive capacity and retention of fluids under pressure, while at the same time providing initial delay in fluid uptake, it may be preferable to utilize such discrete layers when forming the absorbent layer. In this regard. the superabsorbent material can be located remote from the scrubbing laye~° by including a lesa absorbent layer as the lower-most aspect of the absorbent layer. for example, a layer of cellulosic fibers can be located lower (i.e., beneath) than tine superabscarbent material (i.e., between the superabsorbent material and the scrubbing gayer) In a preferred embcadiment, the absorbent larder rvil~ comprise a thermally taonded airlaid web of cellulose fbi;rs (Flint River, available tr~at~o Weyerhaeuser, Wa) arad AL
Thermal C (thermoplastic available from Daiaal:lon a/s, Vardc, Denmark), and a swellable hydrogel-forming superabsorbent polymer. ~fhc superabsorbent polymer is preferably incorporated such that a discrete laver is located near the surtace of the absorbent layer which is remote from the scrubbing layer, preterably~~ a thin layer of, e.g., cellulose fibers (optionally thermally bonded) are positioned above the supc:rabsorbent gelling polymer to enhance containment.
iii. Optional Attachment Layer The cleaning pads of the present invention will optionally have an attachment layer that allows the pad to be connected to the implement's handle or the support head in preferred implements. The attachment layer will be necessary in those embodiments where the absorbent layer is not suitable for attaching the pad to the support head of the handle.
The attachment layer may also function as a means to prevent fluid flow through the top surface (i.e., the handle-contacting surface) of the cleaning pad, and may further provide enhanced integrity of the pad. As with the scrubbing and absorbent layers, the attachment layer may consist of a mono-layer or a multi-layer structure, so long as it meets the above requirements.
In a preferred embodiment of the present invention, the attachment layer will comprise a surface which is capable of being mechanically attached to the handle's support head 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 handle's support head.
To achieve the desired fluid imperviousness and attachability, it is preferred that a laminated structure comprising, e.g., a meltblown film and fibrous, nonwoven structure be utilized. In a preferred embodiment, the attachment layer is a tri-layered material having a layer of meltblown polypropylene film located between two layers of spun-bonded polypropylene.
III. Cieanine Pad While the cleaning pads of the present development were initially constructed for use in the previously-described cleaning implements, the ability to initially delay significant fluid absorption, followed by subsequent uptake and retention of significant amounts of fluid gives the cleaning pads a utility separate from their combination with a handle to form an implement such as a mop. As such, the cleaning pads themselves can be used without attachment to a handle. They may therefore be constructed without the need to be attachable to a handle. I-Iowever, it may be convenient to construct the cleaning pads such that they may be used either in combination with the handle or as a stand-alone product. As such, it may be preferred to prepare the pads with an optional attachment layer. With the exception of not requiring an attachment layer, the pads themselves are as described with respect to the implement.
IV. Other Aspects and Suecific Embodiments of the Invention To enhance the pad's ability to remove tough soil residues and increase the amount of cleaning fluid in contact with the cleaning surface, it may be desirable to incorporate a scrim material into the cleaning pad. The scrim will be comprised of a durable, tough .. ~~j _ material that will provide texture to the pad's scrubbing layer" particularly when in-use pressures are applied to the pad. Preferably, the scrim will be located such that it is in close proximity tco the surface; being cleaned. '('hus, the scrim may he incorporated as part of" the ,scrubbing layer or the absorbent layer; or it rmav be irt~.lr~cied ~~s a distinct lay°er, prefErahly positioned between the scrubbing and absorbent layers. In c}n~; preferred embodiment, where the scrim material is of the same ?i-Y distension as the overall cleaning pad, it is preferred that the scrim material be incorporated such that it does not directly contact, to a significant degree, the surface being cleaned. "I his will tttaintain tl-re ability of the pad to move readily across t he hard surface and w~'ill ai.cl irr pr~:v~:ntirig sort-~ar~il~i>rxwt removal ol'the cleaning, solution employed. As such, if the scrim is pat~l ohthe scrubbing layer, it will toe an upper layer of this component. Of course, the scrim must at the same time be positioned sufficiently low in the pad to provide it'a scrubbing function. 'hhus, i l~ the :~critn is incorporated as part of the absorbent layer, it will be a lower layer thervol: It at separate embodiment, it may be desirable to place the scrim such that it will lee in direct contact with the surface to be cleaned. In this embodiment, depicted specifically in Figure 8, the scrim preferably will not extend to the front and back edges of the cleaning pad, arid therefore the effect of non-unifotmly removing the; cleaning :c>lution and solubilireil soil is avoided.
In addition to t'he importance of ~urol»rly pc:>sitioniry7, tine scrim is that the scrim not significantly impede fluid flow through the pad. ~l'he scrim therefore is a relatively open web, such as that depicted in figure ? of the drawings. ( While the pattern of the scrim depicted in figure 7 is that of multiple "'diamonds'", it is recognized that any shaped structure may be utilized.) Applicants have ~liscovor~;d that ire additioat to ,providing enhanced scrubbing benefits, the. scrim also contribute, to the initial delay ~le~~ir~d by the pads.
The scrim material will be any material that cats be processed to provide a tough, open-textured web. Such materials include pcylyolefins (e.g., polyethylene, polypropylene), polyesters, polyamides, and the like. '1'h~ skilled artisan will recognize that these different materials exhibit a different d egree oi' har~dnc~ss. ~l'kmrs, the her°d ese of' the scrim material can be controlled, depending on the end-use of' the padiimplement. Where the scrim is incorporated as a discrete layer, many commercial sources of such materials are available (e.g., design number V01230, available front C'c~rrwcd Plastics, Minneapolis, MN).
Alternatively, the scrim may be incoyorat~;cl Ipy hrintin,g a resin or other synthetic .material (e.g. latex) onto a substrate, such ors is disclosed in L..i..S. 1:'~tter~t TJo. 4,745,,021, .issued .May 17, 1988 to Ping, III et al., and Ct.S. Patent No. 4,73;6,774, issued 'March 29, 1988 to Ping, II1 et al.

The various layers that comprise the cleaning pad may be bonded together utilizing any means that provides the pad with sufficient integrity during the cleaning process. The scrubbing and attachment layers may be bonded to the absorbent layer or to each other by any of a variety of bonding means, including the use of a uniform continuous layer of adhesive, a patterned layer of adhesive or any array of separate lines, spirals or spots of adhesive. Alternatively, the bonding means may comprise heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds or any other suitable bonding means or combinations of these bonding means as are known in the art. Bonding may be around the perimeter of the cleaning pad (e.g., heat sealing the scrubbing layer and optional attachment layer and/or scrim material), and/or across the area (i.e., the X-Y plane) of the cleaning pad so as to form a pattern on the surface of the cleaning pad. Bonding the layers of the cleaning pad with ultrasonic bonds across the area of the pad will provide integrity to avoid shearing of the discrete pad layers during use.
The cleaning pad of the present invention will be capable of retaining absorbed fluid, even during the pressures exerted during the cleaning process. This is referred to herein as the cleaning pad's ability to avoid "squeeze-out" of absorbed fluid, or conversely its ability to retain absorbed fluid under pressure. The method for measuring squeeze-out is described in the Test Methods section. Briefly, the test measures the ability of a saturated cleaning pad to retain fluid when subjected to a pressure of 0.25 psi.
Preferably, the cleaning pads of the present invention will have a squeeze-out value of not more than about 40%, more preferably not more than about 25%, still more preferably not more than about I S%, and most preferably not more than about 10%.
The cleaning implement of the present invention is preferably used in combination with a cleaning solution. The cleaning solution may consist of any known hard surface cleaning composition. Hard surface cleaning compositions are typically aqueous-based solutions comprising one or more of surfactants, solvents, builders, chelants, polymers, suds suppressors, enzymes, etc. Suitable surfactants include anionic, nonionic, zwitterionic, amphoteric and cationic surfactants. Examples of anionic surfactants include, but are not limited to, linear alkyl benzene sulfonates, alkyl sulfates, alkyl sulfonates, and the tike. Examples of nonionic surfactants ~ include alkylethoxylates, alkylphenolethoxylates, alkylpolyglucosides, alkyiglucamines, sorbitan esters, and the like.
Examples of zwitterionic surfactants include betaines and sulfobetaines.
Examples of amphoteric surfactants include materials derived using imidazole chemistry, such as alkylampho glycinates, and alkyl imino propionate. Examples of cationic surfactants include alkyl mono-, dl-, and tri-ammonium surfactants. All of the above materials are available commercially, and are described in McCutcheon's Vol. 1: Emulsifiers and Detergents, North American Ed., McCutheon Division, MC Publishing Co., 1995.

Suitable solvents include short chain (e.g., C1-C6) derivatives of oxyethylene glygol and oxypropylene glycol, such as mono- and di-ethylene glycol n-hexyi ether, mono-di- and tri-propylene glycol n-butyl ether, and the like. Suitable builders include those derived from phosphorous sources, such orthophosphate and pyrophosphate, and non-phosphorous sources, such as nitrilotriacetic acid, S,S-ethylene diamine disuccinic acid, and the like. Suitable chelants include ethylene diamine tetra acetic acid and citric acid, and the like. Suitable polymers include those that are anionic, cationic, zwitterionic, and nonionic. Suitable suds suppressors include silicone polymers and linear or branched C 10-C 1 g fatty acids or alcohols. Suitable enzymes include lipases, proteases, amylases and other enzymes known to be useful for catalysis of soil degradation.
A suitable cleaning solution for use with the present implement comprises from about 0.1% to about 2.0% of a linear alcohol ethoxylate surfactant (e.g., Neodol I-5~, available from Shell Chemical Co.); from about 0 to about 2.0% of an alkylsulfonate (e.g., Bioterge PAS-8s, a linear Cg sulfonate available from Stepan Co.); from about 0 to about 0.1 % potassium hydroxide; from about 0 to about 0. I % potassium carbonate or bicarbonate; optional adjuvents such dyes and/or perfumes; and from about 99.9% to about 90% deionized or softened water.
Referring to the fgures which depict the cleaning pad of the present invention, Figare 2 is a perspective view of a removable cleaning pad 200 comprising a scrubbing layer 201, an attachment layer 203 and an absorbent layer 205 positioned between the scrubbing layer and the attachment layer. As indicated above, while Figure 2 depicts each of layers 201, 203 and 205 as a single layer of material, one or more of these layers may consist of a laminate of two or more plies. For example, in a preferred embodiment, scrubbing layer 201 is a two-ply laminate of carded polypropylene, where the lower layer is slitted. Also, though not depicted in Figure 2, materials that do not inhibit fluid flow may be positioned between scrubbing layer 201 and absorbent layer 203 and/or between absorbent layer 203 and attachment layer 205. However, it is important that the scrubbing and absorbent layers be in substantial fluid communication, to provide the requisite absorbency of the cleaning pad. While Figure 2 depicts pad 200 as having all of the pad's layers of equal size in the X and Y dimensions, it is preferred that the scrubbing layer 201 and attachment layer 205 be larger than the absorbent layer, such that layers 201 and 205 can be bonded together around the periphery of the pad to provide integrity.
The scrubbing and attachment layers may be bonded to the absorbent layer or to each other by any of a variety of bonding means, including the use of a uniform continuous layer of adhesive, a patterned layer of adhesive or any array of separate lines, spirals or spots of adhesive.
Alternatively, the bonding means may comprise heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds or any other suitable bonding means or combinations of .. ~ ~~
these bonding means as are known in the art. Bonding may ne around the perimeter of the cleaning pad, and/or across the surface of° the cleaning pad so as to form a pattern on the surface of the scrubbing layer 2() 1.
Figure 3 is a blown perspective view of the absorbe;rat layer 305 of an embodiment of a cleaning pad of the present invention. 'fhe cleaning pad's scrubbing layer and optional attachment layer av°e not shown iru Figure 3. Absoabent layer 305 is depicted in this embodiment as consisting of a tri-lamitlate structure;. ~i,he~;if'ically abso~bf~nt layer 305 is shown to consist of a discrete layer of particulate supervabsorbent gelling material, shown as 307, positioned between two discrete layers 3Uti and 3t)8 of fibrous material.
In this embodiment, because of tlt~ region 30'? of high c;c:~nc:~ntration of superabsorbent gelling material, it is preferred that the at~p~rabaor~herrt tnat~ri~rl noi. Lxhibit gel blocking discussed above. In a particularly preferred embodiment, fibrous layers 306 and 308 will each be a thermally bonded Fibrous substrate of' cellulasic fibers, and lower fibrous layer 308 will be indirect fluid communication withi the scrubbing layer (not shown}.
Figure 4 is a cross-sectional view of cleaning pact 4(:~0 having a scntbbing layer 401, an attachment layer 403, anti an absorbent layer 405 positioned between the scrubbing and attachment layers. Cleaning pad 4()0 is slvowra here to Dave absorbent layer 40S smaller, in the X and Y dimensions, than scrubbing layer 401 and attachment layer 403.
L~ay~;rs 401 and 403 are therefore depicted as being bonded to one another slung t:he periphery of the cleaning pad. Also, in this embodiment, absorbent layer 405 is depicted as having two discrete layers 405a and 4CISb. In a prefer-r~~:cl eml7c>din~ent, upper Iaycr 41)5a is a hydt°ophilic ,polymeric fbam material such as that described its l ).S. Patent Nca, 5,(~Si:l,~ 22; and lower layer 405b is a polymeric foam material such as that described in U.S. .Patent 5,550,1 fi7 (DesMarais), issued August 27, 199fi or U.~. Patent fvcr. :~,Sfi~3,l 79. As disccrssed above, each of layers 405a and 405b may be formed using two or more individual lay~:r~ ch'ttre respective mar:erial.
Figure 7 is a blown laerspectiv~. view of a cleaning pad 600 having an optional scrim material 602. This scrim material 602 is depicted as a distinct material positioned between scrubbing layer 601 and absorbent layer fit)5. In another ~;ml~odiment, scrim 602 may be in the form of a printed resin c:~r othe;r synthGaic; rr~ut~;rial ort tlae scr°ubbing layer (i01 (preFerably the upper surface) or the absorbent layer 605 (preferably the lower surface).
Figure 7 also depicts an optional attachrn~;nt layer fi03 that is positiurtcd above absorbent layer 605. As discussed above, the scrim may hrcrvid~~ inrprovcd csla~an~n,~ of soils that are not readily solubilized by the cleaning solution utilized, if any. 'hhe relatively open structure of the scrim 602 provides the necessary fluid communication benueen the scrubbing layer 601 and absorbent layer 605, to provide the requisite absorbency rates and capacity. Again, while Figure 7 depicts each of layers 601, 603 and 605 as a single layer of material, one or more of these layers may consist of two or more plies.
While Figure 7 depicts pad 600 as having ail of the pad's layers of equal size in the X and Y dimensions, it is preferred that the scrubbing layer 601 and attachment layer 603 be larger than the absorbent layer, such that layers 601 and 603 can be bonded together around the periphery of pad 600 to provide integrity. It is may also be preferred that the scrim material 602 be equal size in at least one of the X or Y dimensions, to facilitate bonding at the periphery of the pad with the scrubbing layer 601 and the attachment layer 603. This is particularly preferred when the scrim material is a distinct layer (i.e., is not printed on a substrate). In those embodiments where the scrim is created by printing, e.g., a resin on a substrate, it may not be important that the scrim be located such that it is part of the peripheral bond. The scrubbing layer 601, scrim 602 and attachment layer 603 may be bonded to the absorbent layer or to each other by any of a variety of bonding means, including the use of a uniform continuous layer of adhesive, a patterned layer of adhesive or any array of separate lines, spirals or spots of adhesive. Alternatively, the bonding means may comprise heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds or any other suitable bonding means or combinations of these bonding means as are known in the art. Bonding may be around the perimeter of the cleaning pad, and/or across the surface of the cleaning pad so as to form a pattern on the surface of the scrubbing layer 601.
Figure 8 is a perspective view of a preferred embodiment of a pad 700 comprising a scrim 702. Figure 8 shows an absorbent layer 705, an attachment layer 703 and scrubbing layer 701 that is partially cut away to facilitate illustration of scrim 702. (Scrim 702 may be a distinct layer of material, or may be a component of either the scrubbing layer or absorbent layer.) Pad 700 is depicted as having a lower hard surface-contacting surface 700a and an upper implement-contacting surface 700b. Pad 700 has two opposed side edges 700c, which correspond to the "X" dimension of the pad, and two opposed end edges 700d, which correspond to the "Y" dimension of the pad. (In use, where pad 700 is rectangular in the X-Y dimension, the typical cleaning motion will generally be in the "back and forth direction" indicated by arrow 710.) As is illustrated, in this preferred embodiment, scrim 702 extends to end edges 700d to allow bonding to the attachment layer 703 and the scrubbing layer 701 (though not depicted as such, absorbent layer 705 will preferably be shorter in the X and Y dimensions, to facilitate bonding of the scrim and the attachment and scrubbing layers). However, scrim 702 does not extend to side edges 700c.
Termination of scrim 702 before side edges 700c provides pad 700 with regions 711 of scrubbing layer 701 that do not exhibit the texture of scrim 702 and therefore are relatively smooth. These smooth regions 71 I allow for uniform removal of soiUsolution during the wiping process.
V. Test Methods A. Performance Under Pressure This test determines the gram/gram absorption of deionized water for a cleaning pad that is laterally confined in a piston/cylinder assembly under an initial confining pressure of 0.09 psi (about 0.6 kPa). (Depending on the composition of the cleaning pad sample, the confining pressure may 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).
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.
A suitable apparatus 510 for this test is shown in Figure 5. At one end of this apparatus is a fluid reservoir S I2 (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 piston/cylinder assembly indicated generally as 520_ 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.
Referring to Figure 6, assembly 520 consists of a cylinder 554, a cup-like piston indicated by 556 and a weight 558 that fits inside piston 556. Attached to bottom end of cylinder 554 is a No. 400 mesh stainless steel cloth screen 559 that is biaxially stretched to tautness prior to attachment. The cleaning pad sample indicated generally as 560 rests on screen 559 with the surface-contacting (or scrubbing) layer in contact with screen 559. 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 ail layers contained by the pad from which the sample is cut.) Cylinder 554 is bored from a transparent LEXAN~ rod (or equivalent) and has an inner diameter of 6.00 cm (area =
28.25 cm2), with a wall thickness of approximately 5 mm and a height of approximately 5 cm. The piston 556 is in the form of a Teflon cup and is machined to fit into cylinder 554 within tight tolerances. Cylindrical stainless steel weight 558 is machined to fit snugly within piston 556 and is fitted with a handle on the top (not shown) for ease in removing.
The combined weight of piston 556 and weight 558 is 145.3 g, which corresponds to a pressure of 0.09 psi for an area of 22.9 cm2.
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/cm2/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.
Reservoir 512 is positioned on an analytical balance 516 that is accurate to at least O.OIg with a drift of less thaw0.lg/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 S 12, at the initiation of the measurement, should be approximately 2 mm below the top surface of fritted disc in fritted funnel S 18.
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 piston/cylinder assembly 520 is positioned within funnel 518.
The reservoir should have a sufficiently large diameter (e.g., ~ 14 cm) so that withdrawal of --40 ml portions results in a change in the fluid height of less than 3 mm.
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:
1. Excess fluid on the upper surface of the fritted disc is removed (e.g.
poured) from fritted funnel 518.
2. The solution heighbweight of reservoir 512 is adjusted to the proper level/value.

3. Fritted funnel 518 is positioned at the correct height relative to reservoir 512.
4. Fritted funnel 518 is then covered with fritted funnel cover 522.
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.

6. Valves 528 and 540 are then closed.

7. Valve 540 is then turned so that the funnel is open to the drain tube 544.

8. The system is allowed to equilibrate in this position for 5 minutes.

9. Valve 540 is then returned to its closed position.
Steps Nos. 7-9 temporarily "dry" the surface of fritted funnel 518 by exposing it to a small hydrostatic suction of -5 cm. This suction is applied if the open end of tube 544 extends --5 cm below the level of the fritted disc in fritted funnel 518 and is filled with deionized water. Typically -0.04 g of fluid is drained from the system during this procedure. This procedure prevents premature absorption of deionized water when piston/cylinder assembly 520 i~s positioned within fritted funnel 5 l 8. 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 piston/cylinder assembly 520. 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).
A round die-cut sample 560 is placed in cylinder 554. The piston 556 is slid into cylinder 554 and positioned on top of the cleaning pad sample 560. The piston/cylinder assembly 520 is placed on top of the frit portion of funnel 518, the weight 558 is slipped into piston 556, 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.
Data is recorded at intervals over a total time period of 1200 seconds (20 minutes).
PUP absorbent capacity is determined as follows:
11200 absorbent capacity (glg) _ [Wr(r0) - Wr(r.1200) ' Wffc]/Wds where t1200 absorbent capacity is the g/g capacity of the pad after 1200 seconds, Wr(r0) is the weight in grams of reservoir S I2 prior to initiation, Wr(r.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. It follows that the sample's -2E~-t3o and t9o~ absorbent capacities are measured similarly, except Wr~r3~» arid Wrt,-9~«~ (i.e., the weight of the reservoir at 30 seconds and '900 seconds after initiation, respectively) are used in the above formula., The t;« percent ~tbsorben~y of° the sample is calculated as t3«
absorbent capacity]/[t~?c~c> absorb~er~t capacity '~ 100"~~~.
B. Squeeze-ayt The ability of the cleaning pad to retain t7ui~V wlmn exposed to in-use pressures, and therefor to avoid t7uid "squeeze-out'", is ar~oth~r irr~portant parameter to the present invention. "Squeeze-aut" is measured ors a:rt entire°. cleaning pad by determining the amount of fluid that can be blotted trocr~ the sample with Whatman filter paper under pressures of 0.25 psi ( I .5 kFa~. Squeeze-out is perlorrni;d on a sample that has been saturated to capacity with deionized water via l~urizor~tai wicking (specif cally, via wicking from the surface of the pad consisting of the s~,rubbing or s~uT°faco-contacting layer). (One means for obtaining a saturated sample is descaibed as the Horizontal Gravimetric Wicking method of U.S. Patent lVo. ~,84~3,80~. The fluid-containing sample is placed horizontally in an afrparatus capable cal' supplying the r~:,spec.~tive pressures, preferably by using an air-filled hag that will providcv evenly distributed pressure across the surface of the sample. The sr~,taeeze-c>ut: value is reported as the weight of test fluid lost per weight of the wet sample.

Claims (48)

WHAT IS CLAIMED IS:

1. A cleaning implement comprising:
a. a handle; and b. a removable cleaning pad comprising:
e. a scrubbing layer; and ii. an absorbent layer;
wherein the cleaning pad has a t30 percent absorbency of not more than about 10% of the pad's t1200 absorbent capacity, and a t1200 absorbent capacity of at least about 5 g of deionized water per g of the cleaning pad.

2. The cleaning implement of claim 1 wherein the cleaning pad has a t30 percent absorbency of not more than about 5% of the cleaning pad's t1200 absorbent capacity.

3. The cleaning implement of claim 2 wherein the cleaning pad has a t30 percent absorbency of not more than about 2% of the cleaning pad's t1200 absorbent capacity.

4. The cleaning implement of claim 1 wherein the cleaning pad has a t1200 absorbent capacity of at least about 10 g of deionized water per g of the cleaning pad.

5. The cleaning implement of claim 4 wherein the cleaning pad has a t1200 absorbent capacity of at least about 20 g of deionized water per g of the cleaning pad.

6. The cleaning implement of claim 1 wherein the scrubbing layer is in direct fluid communication with the absorbent layer.

7. The cleaning implement of claim 1 wherein the cleaning pad further comprises an attachment layer, and wherein the absorbent layer is positioned between the scrubbing layer and the attachment layer.

8. The cleaning implement of claim 7 wherein the scrubbing layer is in direct fluid communication with the absorbent layer.

9. The cleaning implement of claim 7 wherein the attachment layer comprises a material that is essentially fluid impervious.

10. The cleaning implement of claim 7 wherein the handle comprises a support head at one end, wherein the support head comprises a means for releasably attaching the cleaning pad to the handle.

11. The cleaning implement of claim 10 wherein the means for releasably attaching the cleaning had are hooks and the attachment layer comprises a material that will act as loops for mechanically attaching to the hooks.

12. The cleaning implement of claim 11 wherein the support head has an upper surface that is pivotably attached to the handle and a lower surface that comprises the hooks for releasably attaching the cleaning pad to the support head.

13. The cleaning implement of claim 1 wherein the cleaning pad further comprises a scrim material.

14. The cleaning implement of claim 13 wherein the scrim material is a distinct layer positioned between the scrubbing layer and the absorbent layer.

15. The cleaning implement of claim 14 wherein the scrim material is a component of the scrubbing layer or the absorbent layer.

16. The cleaning implement of claim 1 wherein the cleaning pad has a squeeze-out value of not more than about 40% at 0.25 psi.

17. The cleaning implement of claim 16 wherein the cleaning pad has a squeeze-out value of not more than about 25% at 0.25 psi.

18. The cleaning implement of claim 1 wherein the absorbent layer comprises a superabsorbent material.

19. The cleaning implement of claim 18 wherein the absorbent layer comprises at least about 15%, by weight of the absorbent layer, of the superabsorbent material.

20. The cleaning implement of claim 19 wherein the absorbent layer comprises at least about 20%, by weight of the absorbent layer, of the superabsorbent material.

21. The cleaning implement of claim 18 wherein the superabsorbent material is selected from the group consisting of superabsorbent gelling polymers and hydrophilic polymeric absorbent foams.

22. The cleaning implement of claim 21 wherein tire absorbent layer comprises at least about 20%, by weight of the absorbent layer, of the superabsorbent material.

23. The cleaning implement of claim 18 wherein the cleaning pad further comprises an attachment layer, and wherein the absorbent layer is positioned between the scrubbing layer and the attachment layer.

24. The cleaning implement of claim 23 wherein the attachment layer comprises a material that is essentially fluid impervious.

25. The cleaning implement of claim 23 wherein the handle comprises a support head at one end and wherein the support head comprises a means for releasably attaching the cleaning pad to the handle.

26. The cleaning implement of claim 25 wherein the means for releasably attaching the cleaning pad are looks and the attachment layer comprises a material that will act as loops for mechanically attaching to the hooks.

27. The cleaning implement of claim 26 wherein the support head has an upper surface that is pivotably attached to the handle and a lower surface that comprises hooks for releasably attaching the cleaning pad to the support head.

28. The cleaning implement of claim 18 wherein the cleaning pad further comprises a scrim material.

29. A cleaning implement comprising:
a. handle comprising a support head at one end; and b. a removable cleaning pad comprising:

i. a scrubbing layer;
ii. an absorbent layer in direct fluid communication with the scrubbing layer; and iii. an attachment layer that is essentially fluid impervious;
wherein the cleaning pad has a t30 percent absorbency of not more than about 5% of the cleaning pad's t1200 absorbent capacity, and a t1200 absorbent capacity of at least about 20 g of deionized water per g of the cleaning pad.

30. The cleaning implement of claim 29 wherein the support head comprises an upper surface that is attached to the handle and a lower surface that comprises hooks for releasably attaching the cleaning pad to the support head.

31. The cleaning implement of claim 29 wherein the cleaning pad has a squeeze-out value of not more than about 25% under 0.25 psi of pressure.

32. The cleaning implement of claim 29 wherein the cleaning pad further comprises a scrim material.

33. A cleaning pad comprising:
a. a scrubbing layer; and b. an absorbent layer;
wherein the cleaning pad has a t30 percent absorbency of not more than about 10% of the cleaning pad's t1200 absorbent capacity, and a t1200 absorbent capacity of at least about 5 g of deionized water per g of the cleaning pad.

34. The cleaning pad of claim 33 having a t30 percent absorbency of not more than about 5% of the cleaning pad's t1200 absorbent capacity.

35. The cleaning pad of claim 34 having a t30 percent absorbency of not more than about 2% of the cleaning pad's t1200 absorbent capacity.

36. The cleaning pad of claim 33 wherein the cleaning pad has a t1200 absorbent capacity of at least about 10 g of deionized water per g of the cleaning pad.

37. The cleaning pad of claim 36 wherein the cleaning pad has a t1200 absorbent capacity of at least about 20 g of deionized water per g of the cleaning pad.

38. The cleaning pad of claim 33 further comprising an attachment layer for mechanically attaching the cleaning pad to a handle of a cleaning implement, wherein the absorbent layer is positioned between the scrubbing layer and the attachment layer.

39. The cleaning pad of claim 38 wherein the attachment layer is essentially fluid impervious and is suitable for being releasably attached to a handle of a cleaning implement having mechanical hooks.

40. The cleaning pad of claim 39 wherein the absorbent layer comprises a superabsorbent material.

41. The cleaning pad of claim 40 wherein the absorbent layer comprises at least about 15%, by weight of the absorbent layer, of the superabsorbent material.

42. The cleaning pad of claim 41 wherein the absorbent layer comprises at least about 20%, by weight of the absorbent layer, of the superabsorbent material.

43. The cleaning pad of claim 41 wherein the superabsorbent material is selected from the group consisting of superabsorbent gelling polymers and hydrophilic polymeric absorbent foams.

44. The cleaning pad of claim 40 wherein the absorbent layer comprises at least about 20%, by weight of the absorbent layer, of the superabsorbent material.

45. The cleaning pad of claim 40 further comprising a scrim material.

46. The cleaning pad of claim 33 further comprising a scrim material.

47. The cleaning pad of claim 33 wherein the cleaning pad has a squeeze-out value of not more than about 40% at 0.25 psi.

48. The cleaning pad of claim 47 wherein the cleaning pad has a squeeze-out value of not more than about 25% at 0.25 psi.