A cleaning implement having controlled fluid absorbency

IS 2 175 487 T5

DESCRIPTION

Cleaning utensil with controlled fluid absorbency.

Technical field

This application relates to a cleaning implement useful for removing dirt from hard surfaces. The application relates in particular to a cleaning implement comprising a handle and a removable absorbent cleaning pad. The application also refers to the absorbent cleaning pad that is used with the cleaning implement. The cleaning pad exhibits the ability to absorb fluids at a controlled rate and retain absorbed fluids during the cleaning process.

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 floor cleaning, numerous devices are described that comprise a handle and some means for absorbing a fluid cleaning composition. Such devices include those that are reusable, including mops containing cotton cords, cellulose and / or synthetic strips, sponges, and the like. Although these mops are successful in removing many soils from hard surfaces, they typically require the inconvenience of performing one or more rinsing operations during use to avoid saturation of the material with dirt, soil, debris, etc. These mops therefore require the use of a separate container to perform the rinsing operation or operations to renew the utensil, and these rinsing operations are usually not successful in sufficiently removing dirt residues. This can result in the re-deposition of significant amounts of soil during subsequent mopping passes. Also, as reusable mops are used for a long time, they become increasingly dirty and smelly. This has a negative effect on the subsequent cleaning efficiency.

To alleviate some of these 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 scrubbing or scouring pad to remove dirt from a mop. dirty surface, a drying layer to absorb fluid after the cleaning process, and a liquid impervious layer located between the scrubbing and drying layers. The pad further contains a breakable package means located between the scrubbing layer and the liquid impermeable layer. The breakable packages are positioned so that, after breakage, fluid is directed onto the surface to be cleaned. During the cleaning action with the scrubbing layer, the waterproof sheet prevents fluid from moving into the absorbent drying layer. After the cleaning action is completed, the pad is removed from the mop handle and reattached in such a way that the drying layer comes into contact with the floor. Although this device can alleviate the need for multiple rinsing operations, it does require the user to physically handle the pad and reattach a soiled, wet pad in order to complete the cleaning process.

Similarly, US Patent 5,419,015, issued May 30, 1995 to Garcia, describes a mop having removable, washable work pads. The pad is described with a top layer that is capable of being attached to hooks on a mop head, a center layer of synthetic microporous plastic foam, and a bottom layer for contacting the surface during the cleaning operation. It is stated that the composition of the undercoat depends on the end use of the device, i.e. washing, polishing or scrubbing. Although this reference faces problems associated with mops that require rinsing in use, the patent fails to provide a cleaning implement that sufficiently removes dirt that is deposited on typical household hard surfaces, particularly floors, such that the surface is perceived as essentially free of dirt.

In particular, the synthetic foam described by Garcia for absorbing cleaning solution has a relatively low absorbent capacity for water and aqueous solutions. Therefore, the user must either use small amounts of cleaning solution, so that they 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 effectiveness of the cleaning pad is not optimal.

Although many known hard surface cleaning devices are successful in removing a large majority of the dirt encountered by the typical consumer during the cleaning process, they are inconvenient and time consuming in requiring one or more cleaning / rinsing operations. Prior art devices that have addressed the issue of convenience and time savings typically do so at the cost of cleaning efficiency. As such, a need persists for a device that offers both convenience and advantageous soil removal. Therefore, it is an object of the present invention to provide a cleaning implement comprising a removable cleaning pad, which alleviates the need to rinse the pad during use and provides a substantially dry result. In particular, it is an object of the present invention to provide a utensil comprising a removable cleaning pad with sufficient absorbent capacity, based on one gram of fluid absorbed per gram of cleaning pad, which allows cleaning a large surface, such as that of a typical hard surface floor (7.5 - 9.3 m²), without the need to renew or change the pad. It is a further object to provide such a cleaning implement in which the pad offers advantageous properties.

ES 2 175 487 T5 dirt removal. When the cleaning implement of the present invention is used in combination with a cleaning solution, it is a further object to provide an essentially dry end result.

The utensil of the present invention is designed to be compatible with all hard surface substrates, including wood, vinyl, linoleum, wax-free floors, ceramic, Formica^®, porcelain, glass, wall panel and the like.

Summary of the invention

The present invention refers to a cleaning utensil comprising:

to. a handle; Y

b. a removable cleaning pad having average deionized water absorbency rate of no greater than about 0.5 g / s, when measured from t = 0 to t = 1200 seconds using the Performance Under Pressure (PUP) method; and an absorbent capacity at₁₂₀₀ of at least about 1 g of deionized water per g of cleaning pad, when measured using the Performance Under Pressure method, the removable cleaning pad comprising a scrub layer and an absorbent layer, and the scrub layer being in direct fluid communication with the absorbent layer.

Although not limited to wet cleaning applications, the present invention is preferably used in combination with a cleaning solution. That is, although the utensil exists initially in a dry state, optimal cleaning efficiency for a typical hard surface will involve the use of a cleaning fluid that is applied to the soiled surface prior to cleaning with the present utensil. During the effort to develop the present cleaning implement, Applicants surprisingly discovered that a critical aspect of cleaning efficiency is controlling the rate of absorbency of the fluid by the cleaning pad. That is, while it is important to absorb essentially all of the fluid cleaning solution during the time a typical user cleans a surface, it is also important to avoid immediate absorption by the cleaning pad. This is generally contrary to the teachings of the prior art to which absorbent articles belong, where it is accepted that rapid, immediate absorbency is desired.

Avoiding rapid absorption allows the cleaning solution to be used more efficiently by emulsifying, diluting and transporting dirt on the pad. In this regard, the cleaning implement of the present invention allows the cleaning of hard surfaces using low levels of cleaning solution, relative to the levels of solution required when using cleaning devices of the prior art. This provides numerous benefits, including a reduction in the cost of the cleaning solution necessary to carry out the cleaning operation. It has been found that by using a cleaning pad that has controlled absorbency, excellent cleaning results can be achieved using dissolution levels no greater than about 67 ml of cleaning solution per square meter of area to be cleaned, while at the same time a pad is provided with a sufficiently high absorbent capacity to provide a substantially dry end result. Without wishing to be bound by theory, it is postulated that the controlled speed provided by the cleaning pad of the present invention allows for an effective reservoir of fluid to contact the ground, helping to dilute and transport dirt into the floor. pad, using fewer volumes of supplemental fluids than required by previous cleaning systems. As such, the present invention further relates to a method of cleaning a hard surface using low levels of a cleaning solution, the method comprising:

(i) applying the cleaning solution to the hard surface to be cleaned, at a level no greater than about 67 ml of cleaning solution per square meter of hard surface; and (ii) scrubbing the hard surface with a cleaning utensil comprising:

to. a handle; Y

b. a removable cleaning pad having an absorbent capacity at ti2oo of at least about 1 g of deionized water per g of cleaning pad, the removable cleaning pad comprising a scrub layer and an absorbent layer, and the scrub layer being in direct fluid communication with the absorbent layer.

Preferably, the method will use about 5.8 to about 87 ml of cleaning solution per square meter of hard surface, more preferably about 22.4 to 44.8 ml per square meter. Preferably, the method will involve the use of a cleaning pad having an absorbent capacity at ti2oo of at least about 5 g / g, more preferably at least about 10 g / g, even more preferably at least about 20 g / g. g, and still more preferably at least about 30 g / g. It should be understood that the method is also extensible to the use of the cleaning pad as a product on its own (ie without a handle).

In addition to having the speed-controlled requirement of absorbency, it is still important that the cleaning pad has the ability to absorb most of the fluid used. In this regard, minimal overall absorbency is a requirement of the cleaning pad. This overall absorbency is also important as it allows the

ES 2 175 487 T5 use of sufficient amounts of cleaning solution (to maximize solution-soil interaction) and ensure that essentially all of the solution and solubilized soil are removed from the surface.

The handle useful in the present invention will optionally comprise, at one end, a pivotally attached support head. The removable cleaning pad comprises:

i. a scrub coat; and ii. an absorbent layer that is preferably in direct fluid communication with the scrubbing layer; and optionally iii. a fastening or attachment layer for releasably fastening the cleaning pad to the handle, preferably to the optional handle support head.

The present invention further relates to a method of cleaning a hard surface, comprising the step of rubbing the surface with an implement or pad of the present invention.

Brief description of the drawings

Figure 1 is a perspective view of a cleaning implement of the present invention, having a built-in fluid dispensing device.

Figure 1a is a perspective view of a cleaning implement of the present invention that does not have a built-in fluid dispensing device.

Figure 1b is a side view of the handle grip of the utensil shown in Figure 1a.

Figure 2 is a perspective view of a removable cleaning pad of the present invention.

Figure 3 is an exploded 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 depicts an enlarged sectional view of the piston / cylinder assembly shown in Figure 5.

Figure 7 depicts an exploded perspective view of another removable cleaning pad of the present invention.

Figure 8 depicts 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 used together in the practice of the present invention. Therefore, 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 be rapidly transferred between two components or layers (eg, scrub layer and absorbent layer) of cleaning pad without substantial build-up, transport, or restriction. using an interposer. For example, tissues, nonwoven webs, construction adhesives, scrim, and the like, may be present between the two distinct components while maintaining "direct fluid communication", as long as they do not essentially impede or restrict fluid as it passes from a component or layer to the other.

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 to a pad component.

As used herein, the term "XY 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 component of the pad.

IS 2 175 487 T5

As used herein, the term "layer" refers to a member or component of a cleaning pad whose primary dimension is XY, that is, along its length and width. It is to be understood that the term layer is not necessarily limited to single layers or sheets of material. Thus, the layer can comprise laminates or combinations of several sheets or bands of the type of materials required. Therefore, the term "layer" includes the terms "layers" and "layered".

As used herein, the term "hydrophilic" is used to refer to surfaces that can be wetted by aqueous fluids deposited on them. Hydrophilic and wettable characters are typically defined in terms of the contact angle and surface tension of the fluids and solid surfaces involved. This is explained in detail in the American Chemical Society publication Contact Angle, Wettability, and Adhesion, edited by Robert F. Gould (Copyright 1964), incorporated herein by reference. A surface is said to be wetted by a fluid (that is, it is hydrophilic) when either the contact angle between the fluid and the surface is less than 90 °, or when the fluid tends to spontaneously spread across the surface , both conditions normally coexisting. Conversely, a surface is considered "hydrophobic" if the contact angle is greater than 90 ° and the fluid does not spontaneously spread across the surface.

As used herein, the term "scrim" (rough cotton fabric) means any durable material that provides texture near the surface of the scrubbing layer of the cleaning pad, and also has a sufficient degree of openness to allow the required movement of fluid into the absorbent layer of the cleaning pad. Suitable materials include materials that have a continuous open structure, such as wire mesh and synthetic screens. The open areas of these materials can be easily controlled by varying the number of interconnected threads that the mesh comprises, controlling the thickness of those interconnected threads, etc. Other suitable materials include those in which the texture is provided by a discontinuous pattern printed on a substrate. In this regard, a durable material (eg, a synthetic or resin) can be printed onto a substrate in a continuous or discontinuous pattern, such as individual dots, brush-like filaments, and / or lines, to provide the required texture. Similarly, the continuous or discontinuous design can be printed on a release material which will then act as the scrim. These designs can be repetitive or they can be random. It will be understood that one or more of the solutions described to provide the desired texture can be combined to form the optional scrim material. The Z-direction height and open area of ​​the scrim and / or scrubbing substrate layer help to control (ie, retard) the rate of liquid flow into the absorbent core material. The height or Z dimension of the scrim and / or scrubbing substrate helps to provide a means to control the volume of liquid in contact with the cleaning surface while at the same time controlling the rate of absorption of liquid into the absorption core material. .

For the purposes of the present invention, a "top" layer of a cleaning pad is a layer that is relatively further away from the surface to be cleaned (ie, in the context of the utensil, relatively closer to the handle of the utensil during use). The term "bottom" layer means, conversely, a layer of a cleaning pad that is relatively closer to the surface to be cleaned (ie, in the context of the utensil, relatively further away from the handle of the utensil during use. ). As such, the scrub layer is the lowermost layer, and the absorbent layer is an upper layer relative to the scrub layer. The terms "top" and "bottom" are used analogously when referring to layers that are multiple (eg, when the scrub layer is a two-layer material).

All percentages, ratios, and proportions used herein are by weight, unless otherwise specified.

II. Cleaning tools

The cleaning utensil of the present invention comprises:

to. a handle preferably comprising, at one end, a pivotally attached support head; Y

b. a removable cleaning pad having average deionized water absorbency rate of no greater than about 0.5 g / s, when measured from t = 0 to t = 1200 seconds using the Performance Under Pressure method; and an absorbent capacity at₁₂₀₀ of at least about 1 g of deionized water per g of cleaning pad, when measured using the Performance Under Pressure method, the removable cleaning pad comprising a scrub layer and an absorbent layer, and the scrub layer being in direct fluid communication with the absorbent layer.

As noted above, Applicants' discovery is based on the finding that a controlled rate of fluid uptake by the absorbent pad improves overall cleaning efficiency. In particular, the cleaning pads have an average absorbency rate of no more than about 0.5 g / s, this average speed being calculated based on the speeds measured during the first 1200 seconds (hereinafter "average absorbency rate" ). Average absorbency rate is determined using the Performance Under Pressure method (hereinafter referred to as "PUP"), which is described in detail in the Test Methods section below. (Briefly, the PUP method measures an absorbency of the cleaning pad at different times under an initial confining pressure of 620 Pa (reflecting typical pressures in use during

ES 2 175 487 T5 cleaning operation)). Preferably, the average absorbency rate will be no greater than about 0.3 g / s, more preferably no greater than about 0.2 g / s, and still more preferably no greater than about 0.1 g / s.

Although the rapid uptake of fluid by the pad is required to be avoided in order for the cleaning pad to achieve the desired cleaning results, it is also necessary for the cleaning pad to absorb more of the fluid used during the cleaning process. As such, the cleaning pads will have an absorbent capacity at 1200 seconds (hereinafter referred to as "absorbent capacity at₁₂₀₀") When measured using the PUP method, of at least about 1 g of deionized water per g of cleaning pad. Preferably, the cleaning pad will have an absorbent capacity at ti200 of at least about 5 g / g, more preferably at least about 10 g / g, and still more preferably at least about 20 g / g, and even more. preferably at least about 30 g / g.

The cleaning pads will preferably, but not necessarily have, a total fluid capacity (of deionized water) of at least about 100g, more preferably at least about 200g, still more preferably at least about 300g, and , most preferably, at least about 400 g. Although pads having a total fluid capacity of less than 100g are within the scope of the invention, they are not as suitable for cleaning large areas, such as found in a typical home, as are larger capacity pads.

One skilled in the art will recognize that various materials can be used to carry out the claimed invention. Thus, while preferred materials for the various components of the utensil and cleaning pad are described below, it is recognized that the scope of the invention is not limited to such descriptions.

A. Mango

The handle of the cleaning tool will be made of any material that facilitates the grip of the cleaning tool. The handle of the cleaning implement will preferably consist of any elongated, durable material that provides practical cleaning. The length of the handle will be dictated by the end use of the utensil.

The handle will preferably comprise, at one end, a support head to which the cleaning pad can be releasably attached. For ease of use, the support head can be pivotably attached to the handle using known joint assemblies. Any suitable means can be used to attach the cleaning pad to the support head, as long as the cleaning pad remains attached during the cleaning process. Examples of suitable fastening means include clamps, hooks and loops (eg Velcro®) and the like. In a preferred embodiment, the support head will comprise hooks on its bottom surface, which will be mechanically attached to the top layer (preferably a different attachment or tie layer) of the absorbent cleaning pad.

A preferred handle, comprising a fluid dispensing means, is depicted in Figure 1 and is fully described in US Patent 5,888,006 to Procter & Gamble. Another preferred handle, which does not contain fluid dispensing means, is depicted in Figures 1a and 1b, and is fully described in US Patent WO 98/12023.

B. Removable cleaning pad

In light of Applicants' discovery that controlled absorbency rates play an important role in the cleaning efficiency of the utensils of the present invention, one of skill in the art will recognize that the fluid absorption rate of the cleaning solution By the cleaning pad is dictated by the solution and materials of the pad. In this regard, volume flow (ie, fluid uptake rate) can be calculated using the Hagen-Poiseuille laminar flow law. The Hagen-Pouseuille law says that the volume flow, q, is calculated according to the following formula:

q = R²[(2ycosP / R) - pgL] / 8LjU in which R is the radius of the tube, γ is the surface tension of the fluid being absorbed, θ is the contact angle at the fluid-solid interface, ρ is the density of the fluid, g is the gravitational constant, L is the wetted length of the tube, and μ is the viscosity of the fluid. From this equation it is clear that the absorbency rate of the cleaning pad is controllable, for example, by adjusting the pore size of the material constituting the cleaning pad, adjusting the surface wettability (^ θ) of the material for the absorbed fluid. , etc. In conjunction with the teachings of the present disclosure, any of the well-known absorbent materials can be used and can be combined to achieve the desired initial delay of absorbency, except total absorbent capacity. Therefore, while representative materials and embodiments useful for the cleaning pad are described below, the invention is not limited to such materials and embodiments.

IS 2 175 487 T5

i. Scrubbing or scouring pad

The cleaning pad of the present invention will comprise a scrubbing layer and an absorbent layer. The scrub coat is the part of the cleaning pad that comes into contact with the dirty surface during cleaning. As such, materials useful as a scrub coat must be durable enough for the coat to maintain its integrity during the cleaning process, without damaging the surface to be cleaned. In addition, when the cleaning pad is used in combination with a solution, the scrubbing layer must be able to absorb liquids and dirt and release those liquids and dirt to the absorbent layer. This will ensure that the scrub coat is able to continuously remove additional material from the surface being cleaned. Regardless of whether the utensil is used with a cleaning solution (that is, in the wet state) or without cleaning solution (that is, in the dry state), the scrub coat, in addition to removing particulate matter, will facilitate other functions, such as polishing, dust suppression and polishing of the surface being cleaned.

The scrubbing layer can be a monolayer or a multilayer structure, one or more of which layers can be split to facilitate scrubbing of the soiled surface and pick-up of particulate matter. This scrub coat, when it passes over the soiled surface, interacts with the dirt (and with the cleaning solution, when used), loosening and emulsifying tough soils and allowing them to pass freely into the absorbent layer of the pad. The scrubbing layer preferably contains openings (eg, grooves) that provide easy passage for large particulate soil to move freely and become trapped within the absorbent layer of the pad. Low density structures are preferred for use as a scrubbing layer, to facilitate transport of particulate matter into the absorbent layer of the pad.

In order to provide the desired integrity, materials particularly suitable for the scrub coat include synthetic materials such as polyolefins (for example polyethylene and polypropylene), polyesters, polyamides, synthetic cellulosic substances (for example Rayon^®) and their mixtures. Such synthetic materials can be made using known processes, such as carding, spunbonding, meltblowing, airlaying, needle punching, and the like.

ii Absorbent layer

The absorbent layer serves to retain any fluid and dirt absorbed by the cleaning pad during use. Although the scrub layer has some effect on the ability of the pad to provide the required fluid absorption rates, the absorbent layer plays an important role in achieving the absorption rates and overall absorbency of the present invention.

The absorbent layer will be able to remove fluid and dirt from the scrubbing layer so that the scrubbing layer will have the ability to continuously remove dirt from the surface. The absorbent layer must also be able to retain absorbed material under typical in-use pressures to avoid "crushing out" of absorbed soil, cleaning solution, etc.

The absorbent layer consists of any material that is capable of absorbing fluids at required speeds, and of retaining such fluids during use. To achieve the desired full fluid capacities, it is preferred to include in the absorbent layer 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 2.1 kPa. Because most of the cleaning fluids useful with the present invention are water-based, it is preferred that superabsorbent materials have a relatively high g / g capacity for water and aqueous fluids.

Representative absorbent materials include water-swellable, water-insoluble superabsorbent gelling polymers (referred to herein as "superabsorbent gelling polymers"), which are well known in the literature. These materials show very high absorbent capacities for water. The superabsorbent gelling polymers useful in the present invention can have variable sizes, shapes and / or morphologies over a wide range. These polymers can be in the form of particles that do not have a large ratio of maximum dimension to minimum dimension (eg, granules, flakes, powders, aggregates between particles, cross-linked aggregates between particles, 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 advantage of causing improved retention of the superabsorbent material, relative to the particles, during the cleaning process. Although their capacity is generally lower for water-based blends, these materials still show significant absorbent capacity for such blends. The patent literature is replete with descriptions of water swellable materials. See, for example, US Patents 3,699,103 (Harper et al.), Issued June 13, 1972; 3,770,731 (Harmon), issued June 20, 1972; Reissued Patent Re 32,649 (Brandt et al.), reissued April 19, 1989; 4,834,735 (Alemany et al.), Issued May 30, 1989.

Superabsorbent gelling polymers useful in the present invention include a variety of water-insoluble, but water-swellable polymers capable of absorbing large amounts 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

ES 2 175 487 T5 poly (vinyl ethers); Cationic types such as polyvinyl-pyridine, polyvinyl-morpholinone, and N, N-dimethylaminoethyl or N, N-diethylaminopropyl acrylates and methacrylates, and their respective quaternary salts. Typically, the superabsorbent gelling polymers useful in the present invention have a plurality of anionic functional groups, such as sulfonic acid, and, more typically, carboxy groups. Examples of suitable polymers for use herein include those prepared from polymerizable, unsaturated, acid-containing monomers. Thus, such monomers include olefinically unsaturated acids and anhydrides containing at least one olefinic double carbon to carbon bond. More specifically, these monomers can be selected from olefinically unsaturated carboxylic acids and anhydrides, olefinically unsaturated sulfonic acids, and mixtures thereof.

Some non-acid monomers can also be included, usually in minor amounts, in the preparation of the superabsorbent gelling polymers useful herein. Such non-acid monomers can include, for example, esters of the acid-containing, water-soluble or water-dispersible monomers, as well as monomers that contain no carboxylic or sulfonic acid groups at all. Optional non-acid monomers can therefore include monomers containing the following types of functional groups: carboxylic or sulfonic acid esters, hydroxyl groups, amide groups, amino groups, nitrile groups, quaternary ammonium salt groups, aryl groups (for example, phenyl groups, such as those derived from styrene monomer). These non-acid monomers are well known materials and are described in more detail, for example, in US Patent 4,076,663 (Masuda et al.), Issued February 28, 1978, and US Patent 4,062. 817 (Westerman), issued December 13, 1997.

Olefinically unsaturated carboxylic acid and carboxylic acid anhydride monomers include the acrylic acids typified by acrylic acid itself, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, acanoacrylic acid, jd-methylacrylic acid (crotonic acid), α-phenylacrylic acid , jd-acryloxypropionic acid, sorbic acid, α-chlorosorbic acid, angelic acid, cinnamic acid, p-chlorokinamic acid, jd-sterilacrylic acid, itaconic acid, citraconic acid, Mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxyethylene, and maleic acid anhydride.

Olefinically unsaturated sulfonic acid monomers include aliphatic or aromatic vinyl sulfonic acids, such as vinyl sulfonic acid, allylsulfonic acid, vinyl toluene sulfonic acid, and styrene sulfonic acid; Acrylic and methacrylic sulfonic acid, such as sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-methacryloxypropylsulfonic acid and 2-acrylamide-2-methylpropane sulfonic acid.

Preferred superabsorbent gelling polymers for use in the present invention contain carboxy groups. These polymers include hydrolyzed starch-acrylonitrile graft copolymers, partially neutralized and hydrolyzed starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, partially neutralized starch-acrylic acid graft copolymers, vinyl acetate copolymers- saponified acrylic esters, hydrolyzed acrylonitrile or acrylamide copolymers, lightly crosslinked network polymers of any of the foregoing copolymers, partially neutralized polyacrylic acid, and lightly crosslinked network polymers of partially neutralized polyacrylic acid. These polymers can be used either alone or in the form of a mixture of two or more different polymers. Examples of these polymeric materials are described in US Patents 3,661,875,4,076,663, 4,093,776, 4,666,983, and 4,734,478.

The most preferred polymeric materials for use in the manufacture of superabsorbent gelling polymers are slightly cross-linked network polymers of partially neutralized polyacrylic acids and their starch derivatives. More preferably, the hydrogel-forming absorbent polymers comprise from about 50 to about 95%, preferably about 75%, neutralized, lightly cross-linked polyacrylic acid (i.e., polyacrylate / acrylic acid )). The crosslinking of the network renders the polymer essentially insoluble in water and determines, in part, the absorbency and extractable polymer content characteristics of superabsorbent gelling polymers. Procedures for network crosslinking of these polymers, and typical network crosslinking agents, are described in more detail in US Patent 4,076,663.

Although the superabsorbent gelling polymers are preferably of a single type (ie, homogeneous), blends of polymers can also be used in the utensils of the present invention. For example, mixtures of starch-acrylic acid graft copolymers and partially neutralized polyacrylic acid slightly crosslinked network polymers can be used in the present invention.

Although any of the superabsorbent gelling polymers described in the prior art may be useful in the present invention, it has recently been recognized that when significant values ​​(e.g., greater than about 50% by weight of the absorbent structure) of superabsorbent gelling polymers, and in particular when one or more regions of the absorbent layer comprises more than about 50% by weight of the region, the problem of gel blocking by swollen particles can impede fluid circulation, thereby adversely affecting the ability of the polymers. of gelling to absorb to its full capacity in the desired period of time. US Patent 5,147,343 (Kellenberger et al.), Issued September 15, 1992, and US Patent 5,149,335 (Kellenberger et al.), Issued September 22, 1992, describe superabsorbent gelling polymers. in terms of its Absorbency Under Load (AUL: Absorbency Under Load), where the gelling polymers absorb fluids (0.9% saline solution) under a confining pressure of 2.1 kPa. Methods for determining the

IS 2 175 487 T5

AUL are described in these patents. The polymers disclosed therein may be particularly useful in embodiments of the present invention that contain regions of relatively high values ​​of superabsorbent gelling polymers. In particular, when high concentrations of superabsorbent gelling polymer are incorporated into the cleaning pad, these polymers will preferably have an AUL, measured according to the methods described in US Patent 5,147,343, of at least about 24 ml / g, more preferably at least about 27 ml / g, after 1 hour; or an AUL, measured according to the methods described in US Patent 5,149,335, of at least about 15 ml / g, more preferably at least about 18 ml / g after 15 minutes. Commonly assigned U.S. Patent 5,599,335 (Goldman et al.), Filed March 29, 1994, and U.S. Patent 5,562,646 (Goldman et al.), Filed April 6, 1995, are contested. also address the problem of gel blocking and describe superabsorbent gelling polymers useful to overcome this phenomenon. These patents specifically describe superabsorbent gelling polymers that prevent gel blocking even at higher confining pressures, specifically 4.8 kPa. In embodiments of the present invention where the absorbent layer contains regions that comprise high values ​​(eg greater than about 50% by weight of the region) of superabsorbent gelling polymer, it may be preferred that the superabsorbent gelling polymer either as described in the aforementioned Goldman et al. patents.

In addition to the contribution to overall fluid absorbency, the superabsorbent material also directly affects the absorbency rate of the pad. As such, when particulate superabsorbent gelling polymers are employed, the skilled person will recognize that the rate of absorbency of the fluid by the cleaning pad can be controlled by adjusting, for example, the average particle size and / or the size distribution. of the material particles.

Other useful superabsorbent materials include hydrophilic polymeric foams, such as those described in commonly assigned U.S. Patent 5,650,222 (DesMarais et al.), Issued July 22, 1995, and U.S. Patent 5,387,207 (Dyer et al.), issued Feb. 7, 1995. These references describe hydrophilic polymeric absorbent foams made by polymerizing a high internal phase water-in-oil emulsion (commonly referred to as HIPE). These foams are easily structured to provide variable physical properties (pore size, capillarity, suction, density, etc.) that affect fluid handling capacity. As such, these materials are particularly useful, either alone or in combination with others, such as foams or with fibrous structures, to provide the overall capacity required by the present invention.

When 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%, and still more preferably at least 25% of the absorbent layer. superabsorbent material.

The absorbent layer can also consist of, or comprise, fibrous material. Fibers useful in the present invention include naturally occurring fibers (modified or unmodified), as well as synthetically made fibers. Examples of suitable naturally occurring, unmodified / modified fibers include cotton, Esparto grass, bagasse, coarse hair wool, 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, polytetrafluoroethylene, polyvinylidene chloride, polyacrylics such as ORLON^®, poly (vinyl acetate), Rayon^®, poly (ethylene vinyl acetate), insoluble or soluble poly (vinyl alcohol), polyolefins such as polyethylene (for example, PULPEX^®) and polypropylene, polyamides such as nylon, polyesters such as DACRON^® or KODEL^®, polyurethanes, polystyrenes, and the like. The absorbent layer may comprise only naturally occurring fibers, only synthetic fibers, or any compatible combination of naturally occurring or synthetic fibers.

The fibers useful herein can be hydrophilic, hydrophobic fibers, or can be a combination of hydrophilic and hydrophobic fibers. As noted above, the particular selection of hydrophilic or hydrophobic fibers will depend on the other materials included in the absorbent (and, to some extent, scrub) layer. That is, the nature of the fibers will be such that the cleaning pad exhibits the necessary fluid retardation and overall fluid absorbency. Hydrophilic fibers suitable 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 made 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 obtain these southern softwood pulp fibers because of their superior absorbency characteristics. These wood pulp fibers can also be obtained in mechanical processes, such as ground wood, mechanical refiner, thermo-mechanical, chemical-mechanical and chemical-thermomechanical processes. Recycled or secondary wood pulp fibers can be used, as well as bleached and unbleached wood pulp fibers.

Another type of hydrophilic fibers for use in the present invention are chemically rigid cellulosic fibers. As used herein, the term "chemically stiffened cellulosic fibers" means cellulosic fibers that have been chemically stiffened to increase the stiffness of the fibers under both dry and aqueous conditions. Such means may include the addition of a chemical stiffening agent which, for example, magazine and / or

ES 2 175 487 T5 impregnates the fibers. Such means may also include stiffening the fibers by altering the chemical structure, for example by crosslinking of polymer chains.

When the fibers are used as the absorbent layer (or a constituent component thereof), the fibers can optionally be combined with a thermoplastic material. After melting, at least a part of this thermoplastic material migrates to the intersections of the fibers, usually due to capillary gradients between fibers. These intersections become places of attachment for the thermoplastic material. When cooled, the thermoplastic materials at these intersections solidify to form the bonding sites that hold the matrix or fiber web together in each of the respective layers. This can be beneficial in providing additional overall integrity to the cleaning pad.

Among its various effects, bonding at fiber intersections increases the overall compression modulus and strength of the resulting thermally bonded member. In the case of chemically rigid cellulosic fibers, the melting and emigration of the thermoplastic material also has the effect of increasing the average pore size of the resulting web or sheet, while maintaining the density and basis weight of the band as originally formed. This can improve the fluid-receiving properties of the thermally bonded web after initial exposure to fluid, due to improved fluid permeability, and after subsequent exposure, due to the combined ability of the stiffened fibers to maintain their stiffness upon exposure. wetting and the ability of the thermoplastic material to remain attached at the fiber intersections after wetting and after wet compression. Lastly, the thermally bonded bands of stiffened fibers maintain their original overall volume, but the volumetric regions previously occupied by the thermoplastic material remain open, thus increasing the average size of capillary pores between fibers.

Thermoplastic materials useful in the present invention can be in any of a variety of forms, including particles, fibers, or combinations of particles and fibers. Thermoplastic fibers are particularly preferred because of their ability to form numerous inter-fiber bonding sites. Suitable thermoplastic materials can be formed from any thermoplastic polymer that can be melted at temperatures that do not extensively damage the fibers of which the primary web or matrix of each layer is made. Preferably, the melting point of this thermoplastic material will be less than about 190 ° C, and will preferably be between about 75 ° C and about 175 ° C. In any case, the melting point of this thermoplastic material should not be lower than the temperature at which thermally bonded absorbent structures are likely to be stored, when used in cleaning pads. The melting point of the thermoplastic material is normally not less than about 50 ° C.

Thermoplastic materials, and in particular thermoplastic fibers, can be made from a variety of thermoplastic polymers including polyolefins such as polyethylene (for example, PULPEX^®) and polypropylene, polyesters, copolyesters, poly (vinyl acetate), poly (ethyl vinyl acetate), poly (vinyl chloride), poly (vinylidene chloride), polyacrylics, polyamides, copolyamides, polystyrenes, polyurethanes and copolymers of any of the foregoing, such as vinyl chloride / vinyl acetate, and the like. Depending on the characteristics desired 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, for example, from polyolefins such as polyethylene or polypropylene. , polyacrylics, polyamides, polystyrenes, polyurethanes and the like. The surface of the hydrophobic thermoplastic fiber can be made hydrophilic by treatment with a surfactant, such as a nonionic or anionic surfactant, for example by spraying the fiber with a surfactant, by dipping in a surfactant, or by including the surfactant as part of the polymer melt in the production of thermoplastic fiber. After melting and resolidification, the surfactant will tend to remain on the surface 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 trademark Pegosperse® by Glyco Chemical, Inc., of Greenwich, Connecticut. In addition to nonionic surfactants, anionic surfactants can also be used. These surfactants can be applied to thermoplastic fibers at values ​​of, for example, about 0.2 to about 1 g per square centimeter of thermoplastic fiber.

Appropriate thermoplastic fibers can be made from a single polymer (monocomponent fibers), or they can be made from more than one polymer (eg, bicomponent fibers). As used herein, "bicomponent fibers" refers to thermoplastic fibers that comprise a core fiber made from one polymer that is encapsulated within a thermoplastic sheath made from a different polymer. The polymer comprising the cladding frequently melts at a different, usually lower, temperature than the polymer constituting the core. As a consequence, these bicomponent fibers provide thermal bonding due to sheath polymer fusion, while maintaining the desirable strength characteristics of the core polymer.

Bicomponent fibers suitable for use in the present invention may include sheath / core fibers having the following polymer combinations: polyethylene / polypropylene, poly (ethyl vinyl acetate) / polypropylene, polyethylene / polyester, polypropylene / polyester, copolyester / polyester. , and the like. Particularly suitable bicomponent thermoplastic fibers for use herein are those with a polypropylene or polyester core, and a lower melting copolyester, poly (ethyl vinyl acetate) or polyethylene sheath (for example 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" and "eccentric" refer to whether the sheath has a thickness that

ES 2 175 487 T5 is uniform, or uneven, across the cross-sectional area of ​​the bicomponent fiber. Eccentric bicomponent fibers may be desirable to provide more compressive strength at lower fiber thicknesses.

Methods for preparing thermally bonded fibrous materials are described in US Patent 5,607,414 (Richards et al.), Issued March 4, 1997 (see especially pages 16-20), and US Patent 5,549,589 (Horney et al.), Issued Aug. 27, 1996 (see especially columns 9 and 10).

The absorbent layer may also comprise a hydrophilic polymeric foam derived from HIPE, which does not have the high absorbency of those previously described as "superabsorbent materials." Such foams and methods for their preparation are described in US Patent 5,550,167 (DesMarais), issued August 27, 1996; and US Patent 5,563,179, jointly assigned (Stone et al.), issued October 8, 1996.

The absorbent layer of the cleaning pad may be composed of a homogeneous material, such as a mixture of cellulosic fibers (optionally thermally bonded or bonded) and particulate swellable superabsorbent gelling polymer. Alternatively, the absorbent layer may be composed of discrete layers of material, such as a layer of thermally bonded airlaid material, and a discrete layer of a superabsorbent material. For example, a thermally bonded layer of cellulosic fibers may be located lower than (ie, below) the superabsorbent material (ie, between the superabsorbent material and the scrubbing layer). In order to achieve high fluid absorption and retention capacity under pressure, while at the same time providing the initial delay in fluid uptake, it may be preferable to use such discrete layers when forming the absorbent layer. In this regard, the superabsorbent material can be located remote from the scrubbing layer by including a less absorbent layer as the lowermost aspect of the absorbent layer. For example, a cellulosic fiber layer may be positioned lower (ie, below) than the superabsorbent material (ie, between the superabsorbent material and the scrubbing layer).

In a preferred embodiment, the absorbent layer will comprise a thermally bonded air-laid web of cellulose fibers (Flint River, available from Weyerhaeuser, Wa) and AL Thermal C (thermoplastic available from Danaklon a / s Varde, Denmark), and a swellable, hydrogel-forming, superabsorbent polymer. The superabsorbent polymer is preferably incorporated such that a discrete layer is located near the surface of the absorbent layer that is remote from the scrubbing layer. Preferably, a thin layer of, for example, cellulose fibers (optionally thermally bonded) is placed on top of the superabsorbent gelling polymer to improve containment.

iii. Optional holding layer

The cleaning pads of the present invention will optionally have a clamping layer that will allow the pad to be attached to the handle of the utensil or to the support head on preferred utensils. The holding layer will be necessary in those embodiments where an absorbent layer is used, but is not appropriate for attaching the pad to the handle support head. The holding layer can also act as a means to prevent fluid from flowing across the upper surface (ie, the handle contacting surface) of the cleaning pad, and can further provide improved integrity to the pad. As with the scrubbing and absorbent layers, the holding layer can consist of a monolayer or a multilayer structure, as long as it meets the above requirements.

In a preferred embodiment of the present invention, the fastening layer will comprise a surface that is capable of being mechanically attached to the support head of the handle through the use of known hook and loop technology. In one such embodiment, the holding layer will comprise at least one surface that can be mechanically attached to hooks that are permanently attached to the lower surface of the handle support head.

To achieve the desired fluid impermeability and holding ability, it is preferred that a laminate structure is used comprising, for example, a nonwoven fibrous melt blown film structure. In a preferred embodiment, the tie layer is a three layer material having a layer of melt blown polypropylene film, positioned between two spun bonded polyethylene layers.

III. Cleaning pad

Although the cleaning pads of the present development are particularly suitable for use in the cleaning utensils described above, the ability to control the absorption of fluid, followed by the subsequent reception and retention of significant amounts of fluid, imparts to the cleaning pads a Independent utility of combining with a handle to form a utensil, such as a mop. As such, the cleaning pads themselves can be used without being attached to a handle. Therefore, they can be constructed without the need for them to be attached to a handle. However, it may be desirable to construct the cleaning pads in such a way that they can be used either in combination with the handle or as a standalone product. Therefore, it may be preferred to prepare the pads with an optional tie layer. In all other respects, the cleaning pad is essentially as described above. Of course, when the cleaning pad is designed to clean hard surfaces of smaller dimensions than domestic floors11

ES 2 175 487 T5 (eg, countertops, sinks, kitchen surfaces, plumbing, etc.), such pads can be obtained with relatively lower overall capacities.

IV. Other aspects and specific embodiments of the invention

When the cleaning pad is made up of discrete layers, the various layers can be bonded or bonded together using any means that provide the pad with sufficient integrity during the cleaning process. The scrubbing and holding layers, when present, can be attached 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, an adhesive patterned layer, or any series of separate lines, spirals, or dots of adhesive. Alternatively, the bonding means may consist of heat bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other appropriate bonding means or combinations of these bonding means, as known in the art. Bonding can be around the perimeter of the cleaning pad (for example, by heat welding the scrub layer and optional tie layer), and / or across the area (i.e. the XY plane) of the cleaning pad so that a pattern is formed on the surface of the cleaning pad. Bonding the layers of the cleaning pad with ultrasonic bonds across the area of ​​the pad provides integrity to prevent shearing of the individual layers of the pad during use.

The cleaning pad of the present invention will be able to retain absorbed fluid, even under the pressures exerted during the cleaning process. This is referred to herein as the ability of the cleaning pad to prevent "crushing out" of absorbed fluid or, conversely, as the ability to retain absorbed fluid under pressure. The method for measuring crush ejection 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 1.72 kPa. Preferably, the cleaning pads of the present invention will have a squeeze-out value of no more than about 40%, more preferably no more than about 25%, still more preferably, no more than about 15%, and so on. more preferably, no more than about 10%.

The cleaning implement of the present invention is preferably used in combination with a cleaning solution. The cleaning solution can consist of any known hard surface cleaning composition. Hard surface cleaning compositions are typically water-based solutions comprising one or more of surfactants, solvents, builders, chelators, polymers, suds suppressors, enzymes, etc. Suitable surface active agents include anionic, nonionic, zwitterionic, amphoteric and cationic surface active agents. Examples of anionic surfactants include, but are not limited to, linear alkylbenzenesulfonates, alkyl sulfates, alkylsulfonates, and the like. Examples of nonionic surfactants include alkyl ethoxylates, alkyl phenol ethoxylates, alkyl polyglycosides, alkyl glucamines, sorbitan esters, and the like. Examples of zwitterionic surfactants include betaines and sulfobetaines. Examples of amphoteric surfactants include derived materials utilizing imidazole chemistry, such as alkylampho-glycinates, and alkyl imino-propionate. Examples of cationic surfactants include mono-, di- and tri-ammonium surfactants. All of the above materials are commercially available, and are described in Vol. 1 from McCutcheon: Emulsifiers and Detergents, North American Ed., McCutheon Division, MC Publishing Co., 1995.

Suitable solvents include short chain derivatives (for example C₁-C₆) of oxyethylene glycol and oxypropylene glycol, such as mono- and di-ethylene glycol n-hexyl ether, mono-, di- and tripropylene glycol n-butyl ether, and the like. Appropriate builders include those derived from phosphorous sources, such as orthophosphate and pyrophosphate, and non-phosphorous sources, such as nitrile-triacetic acid, S, S-ethylenediamine-disuccinic acid, and the like. Suitable chelators include ethylenediaminetetraacetic 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 C10-C18 linear or branched fatty acids or alcohols. Suitable enzymes include lipases, proteases, amylases, and other enzymes known to be useful for soil degradation catalysis.

A suitable cleaning solution for use with the present implement comprises about 0.1% to 2.0% of a linear alcohol ethoxylate surfactant (eg, Neodol 91-5®, available from Shell Chemical Co.); from about 0 to 2.0% of an alkyl sulfonate (for example Bioterge PAS-8s, a linear sulfonate of C₈, available from Stepan Co.); from about 0 to 0.1% potassium hydroxide; from about 0 to 0.1% potassium carbonate or bicarbonate; from about 0 to 10% organic acids; optional adjuvants, such as dyes and / or perfumes; and about 99.9 to 90% deionized or softened water.

When the superabsorbent polymeric material is used in the cleaning pad, it is possible to control the rate of uptake of fluids by controlling the pH of the cleaning solution. In particular, when such polymers are present, the cleaning solution will preferably have a pH of no greater than about 9, preferably a pH of no greater than about 7, even more preferably a pH of no greater than about 5, and most preferably a pH of around 2 to around 5.

Referring to the figures, which depict the cleaning pads of the present invention, Figure 2 is a perspective view of a removable cleaning pad 200 comprising a scrubbing layer 201, a holding layer 203, and an absorbent layer 205 located between the scrubbing layer and the holding layer. How I know

ES 2 175 487 T5 has previously indicated, although Figure 2 represents each layer 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 sheets. For example, in a preferred embodiment, scrub layer 201 is a laminate of two sheets of carded polypropylene, where the bottom layer sits. Also, although not shown in Figure 2, materials that do not have fluid flow can be located between the scrubbing layer 201 and the absorbent layer 203 and / or between the absorbent layer 203 and the holding layer 205. However, It is important that the scrub and absorbent layers are in essential fluid communication to provide the required absorbency of the cleaning pad. Although Figure 2 depicts pad 200 with all pad layers equal in size in X and Y dimensions, it is preferred that scrub layer 201 and hold layer 205 are larger than absorbent layer, such that layers 201 and 205 can be bonded together around the periphery of the pad to provide integrity. The scrubbing and holding layers can be attached 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, an adhesive patterned layer, and any series of lines, spirals or separate dots of adhesive. Alternatively, the attachment means may consist of heat bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other appropriate bonding means or combinations of these bonding means, as known in the art. The bonding can be made around the perimeter of the cleaning pad and / or across the surface of the cleaning pad so that a pattern is formed on the surface of the scrubbing layer 201.

Figure 3 is an exploded perspective view of absorbent layer 305 of one embodiment of a cleaning pad of the present invention. Specifically, the absorbent layer 305 is shown as a single or discrete layer of particulate superabsorbent gelling material, shown as 307, positioned between two individual layers 306 and 308 of fibrous material. In this embodiment, due to the region 307 of high concentration of superabsorbent gelling material, it is preferred that the superabsorbent material does not exhibit the gel blocking discussed above. In a particularly preferred embodiment, each of the fibrous layers 306 and 308 will be a thermally bonded fibrous substrate of cellulosic fibers, and the lower fibrous layer 308 will be in direct fluid communication with the scrubbing layer (not shown).

FIG. 4 is a cross-sectional view of the cleaning pad 400 having a scrub layer 401, a tie layer 403, and an absorbent layer 405 located between the scrub and tie layers. Cleaning pad 400 is shown here with a smaller absorbent layer 405, in dimensions X and Y, than scrub layer 401 and tie layer 403. Layers 401 and 403 are therefore depicted as bonded together along the periphery of the cleaning pad. Also, in this embodiment, absorbent layer 405 is depicted with two individual layers 405a and 405b. In a preferred embodiment, top layer 405a is a hydrophilic polymeric foam material, as described in commonly assigned US Patent 5,650,222 (DesMarais et al.), Issued July 22, 1995; and bottom layer 405b is a polymeric foam material, such as that described in U.S. Patent 5,550,167 (DesMarais), issued August 27, 1996, or in commonly assigned U.S. Patent 5,563,179 ( Stone et al.), Issued October 8, 1995. As described above, each of the layers 405a and 405b can be formed using two or more individual layers of the respective material.

Figure 7 is a perspective view of a cleaning pad 600 having an optional scrim material 602. This scrim material 602 is depicted as a separate material located between the scrubbing layer 601 and the absorbent layer 605. In another embodiment , the scrim 602 may be in the form of a resin or other synthetic material printed on the scrub layer 601 (preferably the upper surface) or the absorbent layer 605 (preferably the lower surface). Figure 7 also depicts an optional hold-down layer 603 that is positioned on top of absorbent layer 605. As explained above, the scrim can provide improved cleaning of soils that are not readily solubilized by the cleaning solution used, if any. The relatively open structure of scrim 602 provides the necessary fluid communication between scrubbing layer 601 and absorbent layer 605 to provide the required absorbency values ​​and capacity. Also, 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 sheets.

Although Figure 7 depicts the pad 600 with all the pad layers being equal in size in the X and Y dimensions, it is preferred that the scrub layer 601 and the hold layer 603 are 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 may also be preferred that the scrim material 602 is equal in size in at least one of the X or Y dimensions, to facilitate bonding at the periphery of the pad with the scrub layer 601 and the tie layer 603. This is done particularly preferred when the scrim material is a distinct layer (ie not printed on a substrate). In those embodiments where the scrim is created by printing, for example, a resin on a substrate, it may not be important that the scrim is positioned such that it is part of the peripheral bond. The scrub layer 601, scrim 602, and tie layer 603 can be attached to the absorbent layer or to each other by any of a variety of bonding means, including the use of a uniform and continuous adhesive layer, a layer of patterned sticker or any series of separate lines, spirals, or dots of adhesive. Alternatively, the bonding means may consist of heat bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other appropriate bonding means or combinations of these bonding means, as known in the art. Bonding can be made around the perimeter of the cleaning pad and / or across the surface of the cleaning pad so that a pattern is formed on the surface of the scrubbing layer 601.

IS 2 175 487 T5

Figure 8 is a perspective view of a preferred embodiment of pad 700 comprising a scrim 702. Figure 8 shows an absorbent layer 705, a fastening layer 703, and a scrub layer 701 that is partially torn away to facilitate illustration of the scrim 702. (Scrim 702 may be a separate layer of material or it may be a component of the scrubbing layer or absorbent layer). The pad 700 is shown with a lower hard surface contacting surface 700a and an upper utensil contacting surface 700b. Pad 700 has two opposite side edges 700c, corresponding to the "X" dimension of the pad, and two opposite end edges 700d, corresponding to the "Y" dimension of the pad. (In use, when pad 700 is rectangular in the XY dimension, the typical cleaning motion will generally be in the "back-to-front direction" indicated by arrow 710). As illustrated, in this preferred embodiment, scrim 702 extends to end edges 700d to allow attachment to fastening layer 703 and scrubbing layer 701 (although not shown as such, absorbent layer 705 will preferably be more cuts in dimensions X and Y, to facilitate the joining of the scrim and the joining and scrub layers). However, the scrim 702 does not extend to the side edges 700c. The termination of the scrim 702 in front of the side edges 700c provides the pad 700 with regions 711 of scrubbing layer 701 that do not have the texture of scrim 702 and are therefore relatively smooth. These smooth regions 711 allow for uniform soil / solution removal during the cleaning process.

V. Test Methods

A. Behavior under pressure

This test determines the absorption capacity in gram / gram, and the average absorbency rate in g / s of deionized water for a cleaning pad that is laterally confined in a piston / cylinder assembly under an initial confining pressure of 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 over the time of the test.) The objective of the test is to determine the average speed of the cleaning pad to absorb fluid, in a sensible period of time, when the pad is exposed to conditions of use (capillary action and horizontal 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 hydrostatic pressure close to zero.

A suitable apparatus 510 for this test is shown in Figure 5. 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 generally indicated with 516. The other end of apparatus 510 is a sintered or fritted funnel, indicated generically 518, a piston / cylinder assembly indicated generically at 520, which fits inside the funnel 518, and the cylindrical plastic cover of the sintered funnel, generally indicated with 522, which fits over funnel 518 and is open at the bottom and closed at the top, the top having a pin hole. The 510 apparatus has a system for conveying fluid in either direction, consisting of sections of glass capillary tubing, indicated as 524 and 531a, flexible plastic tubing (for example, 0.635 cm ID and 0.952 cm OD 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 528 3-way valve, glass capillary lines 530 and 534 in the main fluid system, and a glass capillary tube section 532 to fill reservoir 512 and then flood the sintered disk in the sintered funnel 518. The stopcock assembly 538 similarly consists of a 3-way valve 540, glass capillary lines 542 and 546 in the main fluid line, and a glass capillary tube section 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 within piston 556. Attached to the lower end of cylinder 554 is a screen 559 of 400 mesh stainless steel cloth that is biaxially stretched in tension prior to clamping. The cleaning pad sample, generally indicated 560, is applied to the 559 screen with the surface contacting (or scrubbing) layer in contact with the 559 screen. (If the sample from which the pad is cut cleaning is designed so that both of its surfaces have to be in contact with the surface during the cleaning operation, the surface that is primarily directed for the initial scrubbing action must be in contact with the screen 559). The cleaning pad sample is a circular sample having a diameter of 5.4 cm. (Although sample 560 is represented as a single layer, the sample will actually consist of a circular sample that has all the layers contained in the pad from which the sample is cut). The 554 cylinder is drilled by a transparent LEXAN® rod (or equivalent) and has an inside diameter of 6.00 cm (area = 28.25 cm²), with a wall thickness of approximately 5 mm and a height of approximately 5 cm. Piston 556 is shaped like a Teflon cup and is machined to fit cylinder 554 within tight tolerances. The cylindrical stainless steel 558 weight is machined to fit tightly within the 556 piston and is mounted with a handle on top (not shown) for ease of removal. The combined weight of the 556 piston and the 558 weight is 145.3 g, which corresponds to a pressure of 620 Pa for an area of ​​22.9 cm².

The components of the apparatus 510 are dimensioned such that the flow rate of deionized water through it, under a hydrostatic head of 10 cm, is at least 0.01 g / cm²/ sec, where the flow rate is normalized by the area of ​​the sintered funnel 518. Particularly impacting factors in the flow rate are the permeability of the sintered disc

ES 2 175 487 T5 in the sintered funnel 518, and the inside diameters of the glass pipes 524, 530, 534, 542, 546 and 531a, and the stopcock valves 528 and 540.

The reservoir 512 is placed 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 programming that can: (i) monitor the change in weight of the balance at predetermined time intervals from the initiation of the PUP test; and (ii) be set to automatically start on a 0.01-0.05 g weight change, depending on the sensitivity of the balance. Capillary tubing 524 entering reservoir 512 must contact neither the bottom of the reservoir nor the cover 514. The volume of fluid (not shown) in reservoir 512 must be sufficient so that no air is blown into the reservoir. capillary line 524 during measurement. The fluid level in reservoir 512, at the beginning of the measurement, should be approximately 2mm below the top surface of the sintered disk of sintered funnel 518. This can be confirmed by placing a small drop of fluid on the sintered disc and gravimetrically monitoring its slow reflux into reservoir 512. This level should not change significantly when piston / cylinder assembly 520 is placed within funnel 518. The reservoir has of having a sufficiently large diameter (eg, about 14 cm) that the removal of portions of about 40 ml will result in a change in fluid height of less than 3 mm.

Before measurement, the assembly is filled with deionized water. The sintered disk in sintered funnel 518 is then flooded so that it is filled with fresh deionized water. Where possible, air bubbles are removed from the bottom surface of the sintered disk and from the system connecting the funnel to the tank. The following processes are performed by sequential operation of the 3-way stopcocks:

1. Excess fluid on the upper surface of the sintered disk is removed (eg, poured) from the sintered funnel 518.

2. Adjust the height / weight of solution in reservoir 512 to the proper level / value.

3. Sintered funnel 518 is positioned at the correct height relative to reservoir 512.

Four. The sintered funnel 518 is then covered with the sintered funnel cover 522.

5. The reservoir 512 and the sintered funnel 518 are balanced with the valves 528 and 540 of the stopcock assemblies 526 and 538 in the open connection position.

6. Then valves 528 and 540 are closed.

7. The valve 540 is then rotated so as to open the funnel for drainage through tube 544.

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

9. The valve 540 is then rotated back to its closed position.

Steps 7-9 temporarily "dry" the surface of the sintered funnel 518 by exposing it to a small hydraulic suction of ~ 5 cm. This suction is applied if the open end of tube 544 extends ~ 5 cm below the level of the sintered disk in sintered funnel 518 and is filled with deionized water. Typically ~ 0.04 g of fluid is drained from the system during this process. This process prevents premature absorption of deionized water when the piston / cylinder assembly 520 is positioned within the sintered funnel 518. The amount of fluid that is drained from the sintered funnel in this process (referred to as the correction weight sintered tube, or "Wffc": fritted funnel correction weight) is measured by performing the PUP test (see below) over a 20 minute time period with no piston / cylinder assembly 520. Essentially all of the fluid drained from the sintered funnel by this process is very quickly reabsorbed by the funnel when the test is started. Thus, it is necessary to subtract this correction weight from the fluid weights removed from the reservoir during the PUP test (see below).

A round die-cut sample 560 is placed for approximately 1 second in a Petri dish containing approximately 1 g of deionized water, and is then immediately placed in cylinder 554. Piston 556 slides into cylinder 554 and is placed in the top of the cleaning pad sample 560. The piston / cylinder assembly 520 is positioned on top of the sintered portion of the funnel 518, the weight 558 is slid onto the piston 556, and the top of the funnel 518 is then covered with the sintered funnel cover 522. After verifying the stability of the balance reading, the test is started by opening valves 528 and 540 so that funnel 518 and reservoir 512 are connected. With self-initiation, data collection begins immediately, when funnel 518 begins to reabsorb fluid.

Data is recorded at intervals over a total time period of about 1200 seconds (20 minutes). The absorbent capacity of PUP is determined as follows:

absorbent capacity ti2oo (g / g) = [Wr₍₁₌oi - Wr ^ oo) - Wffc] / Wds

ES 2 175 487 T5 where the absorbent capacity to you₂oo is the capacity in g / g of the pad after 1200 seconds, Wr_(t=₀₎ is the weight in grams of tank 512 before initiation, Wr_(t=₁₂₀₀₎ is the weight in grams of the deposit 512 1200 seconds after initiation, Wffc is the correction weight of the sintered funnel and Wds is the dry weight of the cleaning pad sample. The speed of fluid absorbency is also measured during the 1200 second test procedure. From the speed results, the mean absorbance speed of the sample pad is obtained during the period t = 0 to t = 1200 seconds.

B. Ejection by crushing

The ability of the cleaning pad to retain fluid when exposed to operating pressures, and thus to avoid "squashing" of fluid, is another important parameter for the present invention. The "squash ejection" is measured on a complete cleaning pad by determining the amount of fluid that can be dried from the sample with Whatman filter paper under pressures of 1.5 kPa. Smash ejection is performed on a sample that has been saturated to its capacity with deionized water by horizontal capillary action (especially, by capillary action from the surface of the pad consisting of the scrubbing layer or in contact with the surface ). A means of obtaining a saturated sample is described in the Horizontal Gravimetric Capillary Action method of US Patent 5,849,805 (Dyer et al.), Issued December 15, 1998. The fluid-containing sample is placed horizontally in an apparatus. capable of supplying the respective pressures, preferably using an air-filled bag that provides evenly distributed pressure across the surface of the sample. Squeeze ejection values ​​are expressed as the weight of test fluid lost per weight of the wet sample.