Three dimensional structures useful as cleaning sheets

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DESCRIPTION

Three-dimensional structures useful as cleaning sheets.

Field of the invention

This invention relates to cleaning sheets suitable in particular for removing and trapping dust, lint, hair, sand, food crumbs, grass and the like.

Background of the invention

The use of nonwoven sheets for dry powder cleaning is known in the art. These types of sheets typically use a composite material of fibers, where the fibers are joined by adhesive, interlacing or other forces. See, for example, US Patent 3,629,047 and US Patent 5,144,729. To provide a durable cleaning sheet, reinforcing means must be combined with the staple fibers in the form of a continuous filament or network structure. See, for example, US Patent 4,808,467, US Patent 3,494,821 and US Patent 4,144,370. Also, to provide a product capable of withstanding the rigors of the cleaning process, older nonwoven sheets have used fibers tightly bonded by one or more of the forces mentioned above. Although durable materials are obtained, this strong bond can be adversely affected by the materials' ability to trap and retain particulate dirt. In an effort to solve this problem, US Patent 5,525397 issued to Shizuno et al. discloses a cleaning sheet comprising a polymeric network layer and at least one nonwoven layer, the two layers being slightly hydroentangled so as to provide a sheet having a low interlacing coefficient. The resulting sheet provides strength and durability, as well as better dust collection performance because the composite fibers are slightly hydroentangled. Sheets that have a low bonding coefficient (ie, no more than 500 µm) are said to offer better cleaning performance because there is a greater degree of fibers available to contact dirt.

Although the sheets disclosed in the '397 patent are claimed to remedy some of the problems present in prior nonwoven cleaning sheets, such sheets appear to have a generally uniform weight per unit area, at least macroscopically; and they are essentially uniform in thickness, again at the macroscopic level. This means that ordinary random weight and gauge fluctuations and variations can occur as a result of differences in fluid pressure during hydrolyzing. However, a structure comprising discrete regions differing in basis weight was not considered. For example, if it is at the microscopic level, the basis weight of a gap between fibers was measured, resulting in an apparent basis weight of zero, when in fact, unless an opening was being measured in the nonwoven structure, the basis weight of said region is greater than zero. Such fluctuations and variations are normal and are an expected result of the hydrolyzing process. Nonwovens having such variations, including those described in the '397 patent, will be construed by one skilled in the art to have substantially uniform basis weight and gauge in the macroscopic sense. The result of a sheet having a uniform weight per unit area is such that the material is not particularly suitable for picking up and catching dirt of different sizes, shapes, etc. Reference is also made to JP06014859A, which discloses a nonwoven cleaning sheet.

As such, there is a continuing need to provide cleaning sheets that offer better soil removal. In this regard, the applicants have found that by providing greater three-dimensionality, in the macroscopic sense, to the wiper sheets, greater soil removal is achieved.

Therefore, it is an object of this invention to solve the problems of the state of the art and in particular to provide a structure more capable of removing and trapping different types of stains. Specifically, it is an object of this invention to provide a nonwoven structure having significant three-dimensionality, which is described in more detail below.

It is another object to provide improved processes for cleaning and desirable benefits for the consumer and user of the sheets, especially packaging the sheets, either in roll form with perforations to separate the sheets or with a means for separating the sheets in useful lengths and packaging them in packages that inform the consumer of the improved processes and / or benefits that can be obtained, especially those benefits that are not intuitively obvious to the consumer. It is another object to provide cleaning sheets with additives, especially those that improve the adhesion of the stain to the substrate and especially those sheets described below with three-dimensional structure, said combinations having special performance benefits and providing said combinations improved benefits.

Summary of the invention

The present invention relates to a cleaning sheet having substantial macroscopic three-dimensionality. As used herein, the term "macroscopic three-dimensionality", when used to describe three-dimensional cleaning sheets, means that the three-dimensional pattern is easily visible to the naked eye when the perpendicular distance between the observer's eye and the plane of the sheet is approximately 30 , 5 cm (12 inches). In other words, the three-dimensional structures of the present invention are cleaning sheets that are not flat, one or both surfaces of the sheet being arranged in multiple planes, the distance between said planes being observable at

ES 2 236 629 T5 with the naked eye when the structure is viewed from about 30.5 cm (12 inches). In contrast, the term "plane" refers to cleaning sheets that have fine-scale surface irregularities on one or both faces, the surface irregularities not being readily visible to the naked eye when the perpendicular distance between the observer's eye and the plane of the band is approximately 12 inches (30.5 cm) or larger. In other words, at the macroscale level, the observer would not observe that one or both surfaces of the sheet exist in multiple planes forming a three-dimensional structure.

The macroscopically three-dimensional structures of the present invention optionally comprise a mesh-like material, which when heated and cooled, contracts to produce a three-dimensional structure. Other materials that provide contractile forces capable of providing three-dimensionality are described below. Macroscopic three-dimensionality is described herein in terms of "mean differential height", which is defined herein as the mean distance between peaks and adjacent valleys of a given surface of a sheet, as well as the "distance between peaks. mean ”, which is the distance between adjacent mean peaks on a given surface. Macroscopic three-dimensionality is also described in terms of the "surface topography index" of the outer surface (s) of the cleaning sheet; The surface topography index is the relationship obtained by dividing the average height differential of a surface by the average distance between peaks of that surface. In one embodiment, both outer surfaces of the sheet will have the mean peak distance and surface topography properties described. The methods for the determination of the mean peak distance and mean differential height are described in detail in the following Test method section.

The mean distance between peaks of at least one outer surface will be 4 to 12 mm. The surface topography index of at least one exterior surface will be 0.01 to 10, preferably 0.1 to 5, more preferably 0.2 to 3, and still more preferably 0.3 to 2. At least one outer surface will have an average height differential of 1 to 3mm.

The sheets of this invention and similar sheets, especially those containing additives in small amounts, as described herein and especially those where the additive is basically uniformly bound over at least one continuous area, can be used in improved processes for cleaning and to provide desirable benefits to the consumer and user of the sheets, some of those benefits not being intuitively obvious to the consumer, as detailed below. It is therefore desirable to package the sheet either in roll form, with perforations to facilitate the separation of the sheets, or with a means to separate the sheets into useful lengths and / or place them in packages that inform the consumer of the improved processes and / or the benefits that can be obtained, especially those that are not intuitively obvious to the consumer. Cleaning sheets with additives, including those with desirable low amounts of such additives, preferably basically uniformly attached, at least in one or more areas, provide, in combination, special performance benefits and such combinations can provide improved benefits, especially when the sheets they have the desired structures set forth herein.

Brief description of the drawings

Fig. 1 is a schematic plan view illustration of a three-layer embodiment of a cleaning sheet of the present invention, wherein the second layer comprises a mesh-like material having filaments that run parallel to the side and sides. edges at the end of the sheet, in which a portion of the first cut layer is shown and in which the surface characteristics of the first layer are omitted for clarity.

Fig. 2 is an illustration of the type shown in Figure 1 showing an alternative embodiment of the present invention in which the second layer filaments are inclined at an angle of approximately 45 degrees to the side and edges of the sheet. cleaner.

Fig. 3 is a schematic plan view illustration of an embodiment of the photograph of Fig. 5 showing the texture of the macroscopically three-dimensional outer surface of the first layer and in particular the protrusions extended on the outer surface of the first layer .

Fig. 4 is a cross-sectional illustration of the sheet taken parallel to one of the second layer filaments and showing parts of the filament that extend between the intersections of the filament, the parts of the filament that are not attached to the first layer, as well as the parts of the filaments that extend between the intersections of the filament and which are not bonded to the third layer.

Fig. 5 is a photomicrograph showing the macroscopically three-dimensional surface texture of the first layer and in particular the elongated protrusions on the surface. The scale in Fig. 5 is in inches.

Fig. 6 is an enlarged photomicrograph of the type shown in Fig. 5 showing an enlarged bulge having branches extending in different directions.

Fig. 7 is a scanning electron photomicrograph showing a perspective view of the macroscopically three-dimensional surface of the first layer.

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Fig. 8 is a scanning electron photomicrograph of a cross section of the cleaning sheet showing parts of filaments extending between the intersections of the filament, which parts of the filaments are not bonded to the first layer.

Fig. 9 is a scanning electron photomicrograph showing the bonding of the first and third layers to the second layer at the intersections of the filament.

Detailed description of the invention

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 "basically consisting of" and "consisting of".

As used herein, the term "hydroentangled" generally implies a process for producing a material wherein a layer of loose fibrous material (eg, polyester) is supported on a patterned element with holes and is subjected to differences of water pressure large enough to cause individual fibers to mechanically interlock to provide a weave. The patterned element with holes can be formed, eg. e.g. from a woven grid, a perforated metal plate, etc.

As used herein, the term "Z dimension" refers to the dimension orthogonal to the length and width of the cleaning sheet of the present invention, or a component thereof. The Z dimension usually corresponds to the thickness of the sheet.

As used herein, the term "XY dimension" refers to the plane orthogonal to the thickness of the cleaning sheet or a component thereof. The X and Y dimensions usually correspond to the length and width, respectively, of the sheet or a component of the sheet.

As used herein, the term "layer" refers to an element or component of a cleaning sheet whose main dimension is XY, that is, along its length and width. It is understood that the term layer is not necessarily limited to individual layers or sheets of material. Thus, the layer can comprise laminates or combinations of several sheets or bands of the type of material required. Accordingly, the term "layer" includes the terms "layers" and "layered".

For the purposes of the present invention, a "top" layer of a cleaning sheet 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. ). Conversely, the term "bottom" layer indicates a layer of a cleaning sheet 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).

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

II. Cleaning sheets

The present invention relates to a cleaning sheet useful for removing dust, lint, hair, grass, sand, food crumbs and other matters of various size, shape, consistency, etc., from a variety of surfaces. Preferably, the cleaning sheets will demonstrate improved cleaning performance in consumer panel analysis.

As a consequence of the wiper blades' ability to reduce, or eliminate by various means, including contacting and adhering, dust, lint, and other airborne matter from surfaces, as well as from the air, the blades will provide further reduction. of the levels of these materials on the surfaces and in the atmosphere, with respect to other products and practices for similar cleaning purposes. This ability is especially evident in sheets containing additives as described herein. Even the sheets of US Pat. No. 5,525,397, previously incorporated herein, can provide this benefit, albeit to a lesser degree than the preferred structures of the present invention. invention, and therefore it is important to provide this information in the container, or associated with the container, in order to encourage the use of the sheets, including those of the aforementioned '397 patent, especially on non-traditional surfaces such as walls, ceilings, upholstery, covers, carpets, clothing, etc., where sheets have not normally been used to trap dust. The use of a small amount of additive, uniformly attached to at least a preferably continuous area of ​​the sheet in an amount effective to improve adhesion of soil, especially in the form of particles causing an allergic reaction, provides a surprising level of control. on the adhesion of dirt. At least in those areas where the additive is present on the sheet, this small amount is important for such use since, contrary to what happens with other dust cleaning operations where oils are applied as liquids or as sprays, there is much less danger of creating a visible stain, especially on such non-traditional surfaces where the sheet is used. Preferred structures also provide benefits by trapping larger particles rather than eroding them into smaller sizes.

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Consumers with allergies especially benefit from the use of the sheets of the present invention, especially the preferred structures, since allergens are typically in powder form and it is especially desirable to reduce the level of respirable small particles. For this advantage it is important to use the sheets regularly and not only when the dirt becomes visibly apparent, as is the case in the state of the art procedures.

The cleaning sheets of the present invention are manufactured using a non-woven process. Therefore, the preferred structures are non-woven and, especially, those formed by hydrolyzing, as is well known in the art, since they allow obtaining very desirable open structures. Materials especially suitable for shaping the preferred nonwoven cleaning sheet of the present invention include, for example, natural and synthetic cellulosic materials, such as polyolefins (eg polyethylene and polypropylene), polyesters, polyamides, synthetic cellulosic materials (eg. eg Rayon^®) and mixtures thereof. Natural fibers, such as cotton or blends thereof, and those derived from cellulosic sources are also useful. Preferred starting materials for the manufacture of the hydroentangled fiber sheets of the present invention are synthetic materials, which may be in the form of carded, spunbonded, melt blown, airlaid, or other structures. Polyesters are especially preferred, especially carded polyester fibers. The degree of hydrophobicity or hydrophilicity of the fibers is optimized depending on the desired objective of the sheet or the type of soil to be removed, the type of additive provided, if an additive is present, biodegradability, availability and combinations of such considerations. In general, the most biodegradable materials are hydrophilic, although the most effective materials tend to be hydrophobic.

Cleaning sheets can be formed from a single fibrous layer, although they are preferably a composite material of at least two individual layers. Preferably the sheets are non-woven sheets made by a hydrolyzing process. In this regard, prior to hydroentangling discrete layers of fibers, it may be desirable to lightly interlock each of the layers prior to interlacing the layers.

In a particularly preferred embodiment of the present invention, to reinforce the integrity of the final sheet, it is preferred to include a polymeric network (referred to herein as a "mesh" type material) that is arranged together with the fibrous material, e.g. . eg, by heat lamination or by chemical means, such as adhesives, by hydrolyzing, etc. Mesh-type materials useful in the present invention are described in detail in US Patent 4,636,419, which is incorporated by reference herein. Mesh-type materials can be formed directly in the extrusion die or can be derived from extruded films by fibrillation or stamping, followed by stretching and stripping. The mesh can be derived from a polyolefin, such as polyethylene or polypropylene, copolymers thereof, poly (butylene terephthalate), polyethylene terephthalate, nylon 6, nylon 66, and the like. Mesh-type materials are marketed by various suppliers. A preferred mesh useful in the present invention is a polypropylene mesh, commercially available from Conwed Plastics (Minneapolis, MN).

In another aspect of the present invention, Applicants have also discovered that incorporation of the mesh-like material into a cleaning sheet followed by heating provides a macroscopic three-dimensional character to the sheet. This macroscopic three-dimensionality has been found to greatly enhance the cleaning ability of the cleaning sheet, even when the basis weight of the sheet is practically uniform. In particular, macroscopic three-dimensionality is achieved when the mesh / fiber composite is subjected to heat and then cold. This process produces the contraction (in the XY dimension) of the mesh and because it is attached to the fibers, it provides a sheet with a greater three-dimensionality. The degree of added three-dimensionality is controlled by the level of heat applied to the mesh / cleaner combination. The inclusion of a mesh is particularly beneficial when the fiber appearance of the structure is non-woven, particularly when the structure is hydroentangled.

In this regard, the invention relates to macroscopically three-dimensional cleaning sheets. These sheets are preferably relatively open structures compared to, e.g. ex. paper towels. In a preferred embodiment, macroscopically three-dimensional cleaning sheets have a first surface and a second surface and comprise a mesh. In a preferred embodiment, the cleaning sheet has a first outer surface and a second outer surface, and comprises a mesh-like material, the mean distance between peaks of at least one outer surface being 4 to 12 mm, and the index being surface topography of said surface or surfaces from about 0.01 to about 5.

Regardless of the configuration of the wiper blades, the average peak spacing of at least one outer surface will be 4 to 12mm. The surface topography index of at least one exterior surface will be 0.01 to 10, preferably 0.1 to 5, more preferably 0.2 to 3, and still more preferably 0.3 to 2. At least one outer surface will have an average height differential of 1 to 3mm.

Again and with respect to the macroscopically three-dimensional cleaning sheets of the present invention, these structures will provide better elongation, particularly in the CD direction, which will improve their formability, regardless of whether it is used as a single product or if it is used in combination with a cleaning tool. In this regard, the macroscopically three-dimensional sheets will preferably have a CD elongation value with 500 g of at least 3%, more preferably at least 6%, more preferably at least 10%, still more preferably at least 15% and even more preferably 20 %.

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The cleaning performance of any of the cleaning sheets of the present invention can be enhanced by treating the fibers of the sheet, especially with a surface treatment with any of a variety of additives, including surfactants or lubricants, that increase the adhesion of soil to the soil. sheet. When used, such additives are added to the cleaning sheet in an amount sufficient to enhance the ability of the sheet to adhere to stains. Said additives are preferably applied to the cleaning sheet in an added amount of at least 0.01%, more preferably of at least 0.1%, more preferably of at least 0.5%, more preferably of at least 1%, still more preferably at least 3% and even more preferably at least 4%, by weight. Typically, the amount added is 0.1 to 25%, more preferably 0.5 to 20%, more preferably 1 to 15%, still more preferably 3 to 10%, still more preferably 4 to 8 % and most preferably 4 to 6%, by weight. A preferred additive is a wax or a mixture of an oil (eg mineral oil, petroleum jelly, etc.) and a wax. Suitable waxes include various types of hydrocarbons, as well as esters of certain fatty acids (e.g. g., saturated triglycerides) and fatty alcohols. They can be derived from natural sources (i.e. animal, plant, or mineral) or they can be synthesized. Mixtures of these various waxes can also be used. Some representative animal and vegetable waxes that can be used in the present invention include beeswax, carnauba wax, whale oil, lanolin, shellac, candelilla, and the like. Representative waxes of mineral sources that can be used in the present invention include petroleum-based waxes, such as paraffin, petrolatum, and microcrystalline wax, and fossil or mineral waxes, such as white ceresin wax, yellow ceresin wax, white ozokerite wax, and the like. Representative synthetic waxes that can be used in the present invention include ethylenic polymers, such as polyethylene wax, chlorinated naphthalenes, such as "Halowax", hydrocarbon-type waxes prepared by Fischer-Tropsch synthesis, and the like.

When using a mixture of mineral oil and wax, the components will preferably be mixed in an oil: wax ratio of 1:99 to 7: 3, more preferably 1:99 to 1: 1, even more preferably 1:99 to 3: 7, by weight. In a particularly preferred embodiment, the oil: wax ratio is 1: 1, by weight, and the additive is applied in an added amount of about 5% by weight. A preferred mixture is a 1: 1 mixture of mineral oil and paraffin wax.

A particularly enhanced cleaning performance is achieved when the macroscopic three-dimensionality and the additive are provided on the same cleaning sheet. As described hereinabove, these small amounts are especially desirable when the additives are applied in an effective amount and preferably in a substantially uniform manner to at least a discrete continuous area of ​​the sheet. The use of preferred minute amounts, especially additives that improve the adhesion of dirt to the sheet, provides surprisingly good cleaning, suppression of air dust, consumer preferred prints, especially tactile prints, and furthermore, the additive can provide a means of incorporating and adding perfumes, pest control ingredients, antimicrobial agents, including fungicides, and a host of other beneficial ingredients, especially those that are soluble or dispersible in the additive. These benefits are included for illustrative purposes only. When the additive can have adverse effects on the substrate, the packaging and / or the surfaces to be treated are especially desirable small amounts of additives.

The means of applying these additives preferably apply at least a significant amount of the additive at points on the sheet that are "within" the sheet structure. It is a special advantage of three-dimensional structures that the amount of additive that is in contact with the surface to be treated and / or the container, is limited, so that materials that could otherwise cause damage or interfere with the function of the other surface may cause only limited adverse effects or no adverse effects. The presence of the additive within the structure is very beneficial in that the dirt that adheres within the structure is much easier to remove by cleaning the sheet afterwards.

FIG. 1 illustrates a multilayer cleaning sheet 20 according to the present invention. Cleaning sheet 20 includes side edges 22 and end edges 24. Side edges 22 extend generally parallel to the length of sheet 20 and end edges 24 extend generally parallel to the width of the sheet. Optionally, sheet 20 may include an edge seal 26 that extends around the perimeter of the sheet. Such an edge seal 26 can be formed by heating, using adhesives, or by a combination of heat and adhesives.

The cleaning sheet 20 includes a first layer 100 and a second layer 200. Preferably, the cleaning sheet also includes a third layer 300. The second layer 200 may be disposed between the first layer 100 and the third layer 300. In Fig. 1 , a portion of the first layer 100 is shown cut away to reveal underlying portions of the second layer 200 and the third layer 300.

The first layer 100 is formed from nonwoven materials. Especially preferred materials are nonwoven webs having randomly distributed fibers or filaments as in "air deposition" processes or in certain "wet deposition" processes or with a degree of orientation as in certain "air deposition" processes. wet ”and“ carding ”. The fibers or filaments of the first layer 100 can be natural or of natural origin (e.g. Cellulosic fibers, such as pulp fibers, cotton lint, rayon, and bagasse fibers) or synthetic fibers (eg, polyolefins, polyamides, or polyesters). The third layer 300 can be basically the same as the first layer 100, or alternatively, it can be of a different material and / or construction.

In one embodiment, the first layer 100 and the third layer 300 may each comprise a hydroentangled fabric of nonwoven fibers having a denier of less than about 4.0, preferably less

ES 2 236 629 T5 of about 3.0, more preferably less than about 2.0 grams, per 9000 meters of fiber length. A suitable first layer 100 (as well as a third layer 300) is a hydroentangled fabric of polyester fibers having a denier of about 1.5 grams or less per 9000 meters of fiber length and the fabric having a basis weight of about 30 grams per square meter. A suitable fabric is available from PGI Nonwovens of Benson, NC under the designation PGI9936.

Second layer 200 is discontinuously bonded to first layer 100 (and third layer 300 when present) and provides for shrinkage of the first layer by shrinkage of the second layer. Shrinkage mechanisms include, but are not limited to, heat shrinkage and elastic properties of the second layer. As described above, in such an embodiment, the second layer 200 comprises a web-like arrangement of filaments having openings defined by adjacent filaments. Alternatively, the second layer could be in the form of a polymeric film, with possible openings therethrough; to obtain the necessary contraction mechanism, said films must have sufficient elasticity to achieve the retraction function that results in surface three-dimensionality. The film may be etched to provide surface depressions instead of or in addition to openings. In another alternative, contractile effects can be generated by including fibers that contract by heating and cooling again. In this method, some of the fibers will not contract because they are mechanically associated with the shrinkable fibers, the entire sheet will "pucker" as the shrinkable fibers contract, provided that said fibers are included in an amount enough.

In the illustrated embodiments, the second layer comprises a network-like arrangement of filaments including a first plurality of filaments 220 and a second plurality of filaments 240. The filaments 220 extend generally parallel to each other and the filaments 240 extend generally in parallel to each other and generally perpendicular to filaments 220. The filaments extend between the intersections between filaments 260. Adjacent intersecting filaments 220 and 240 define apertures 250 in second layer 200. The intersections between filaments and apertures 250 are arranged in a generally non-random and repeating grid-like pattern.

The second layer 200 may comprise a polymeric network (referred to herein as "mesh-like material"). Suitable mesh-type materials are described in US Patent 4,636,419 incorporated herein by reference. The mesh can be derived from a polyolefin such as polyethylene or polypropylene, or copolymers thereof, poly (butylene terephthalate), polyethylene terephthalate, Nylon 6, Nylon 66, and the like, and mixtures thereof.

The mesh-like material is preferably bonded to layers 100 and 300 by heat lamination or by chemical means such as adhesives. Preferably, the filaments of the mesh-like material contract relative to layers 100 and 300 when heated, such that contraction of second layer 200 causes shrinkage of layers 100 and 300 and imparts a macroscopic three-dimensional texture to the surfaces. exteriors of layers 100 and 300, as described in more detail below.

An especially suitable mesh type material useful as a second layer 200 is a heat activated reinforcing mesh, sold by Conwed Plastics, of Minneapolis, MN, under the trade name THERMANET reinforcing mesh, having a polypropylene / EVA resin. , 2-sided adhesive, and a filament count of 3 filaments per 2.54 cm (per inch) by 2 filaments per 2.54 cm (per inch) prior to shrinkage, such as by heating. After heating, the second layer 200 may have from about 3.5 to 4.5 strands per 2.5 cm (per inch) to about 2.5 to 3.5 strands per 2.5 cm (per inch).

The term "2-sided adhesive" means that the EVA (Ethyl Vinyl Acetate Adhesive) adhesive is present on both sides of the filaments. The EVA activation temperature is generally 85 ° C (185 ° F). During lamination of layer 200 with the polyester fibers of layers 100 and 300, the EVA adhesive is activated to obtain a bond between the filaments of layer 200 and the fibers of layers 100 and 300. Without wishing to be a theoretical limitation, it is considered that by exerting a relatively low pressure (for example, less than 344737 Pa [50 psi], and more preferably, less than 172368 Pa [25 psi]) for a relatively short period of time ( eg, less than about 30 seconds) the filaments of layer 200 are not continuously bonded to the nonwoven material of layers 100 and 300. This discontinuous bonding, in addition to the contraction of the polypropylene filaments with heat, makes it possible to obtain an improved texture of the outer surfaces of layers 100 and 300.

In Fig. 1, the filaments 220 extend generally parallel to the lateral edges 22 and the length of the sheet 20. Also, the filaments 240 extend generally parallel to the terminal edges 24 and the width of the sheet 20.

Alternatively, the filaments 220 may be inclined at an angle of between about 20 and about 70 degrees relative to the length of the sheet 20 and the side edges 22 and more preferably between about 30 degrees and about 60 degrees. The filaments 240 may be inclined at an angle of between about 20 and about 70 degrees with respect to the width of the sheet 20 and the end edges 24 and more preferably between about 30 degrees and about 60 degrees.

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Fig. 2 shows an embodiment of the present invention in which the filaments 220 are inclined at an angle of approximately 45 degrees with respect to the lateral edges 22 (Angle A in Fig. 2) and in which the filaments 240 are inclined at an angle of approximately 45 degrees with respect to the terminal edges 24 (Angle B in Fig. 2). Such an arrangement provides the advantage that the angled orientation of the filaments 220 and 240 with respect to the length and width of the sheet 20 allows the deformation of the net-like structure of the layer 200 that runs parallel to the edges 22 and 24. This type of deformation gives the sheet an elastic-like behavior parallel to the length and width of the sheet.

By the term "elastic-like behavior" is meant that the element in question can be elongated under tension in a direction having an elongated dimension measured so that it is at least 120% of the original relaxed dimension of the element in that direction and when the elongation stress is released, the element recovers up to 10% of its relaxed dimension.

An important aspect of one embodiment of the present invention is that the first layer 100 is intermittently bonded to the second layer 200. In particular, the first layer 100 may be intermittently bonded to the second layer 200 at intersections with the filaments 260, although parts of filaments 220, parts of filaments 240, or parts of both filaments 220 and 240 between the intersections of filament 260 remain unbonded to first layer 100.

As a result, the texture of the outer surface of the first layer 100 is not limited by the geometry of the apertures in the web-like arrangement of the filaments, but rather is decoupled from the non-random repeating geometry of the apertures 250. Likewise, the third layer 300 may be intermittently bonded to the second layer 200 to provide a surface texture similar to the outer surface of the third layer 300.

For clarity the surface texture of the first layer 100 in Figs. 1 and 2. The surface texture is shown in Figs. 3-8.

Fig. 3 provides a schematic illustration of the surface texture of the first layer 100 shown in the photograph of Fig. 5. Fig. 4 provides a cross-sectional illustration of the surface texture of the first layer 100 and the third layer 300. Fig. 5 is a photomicrograph showing the macroscopically three-dimensional surface texture of the first layer 100. Fig. 6 is a photomicrograph showing the three-dimensional surface of the elongated first layer 100. Fig. 7 is a scanning electron photomicrograph providing a perspective view of the three-dimensional surface of the first layer 100. Fig. 8 is a scanning electron photomicrograph of a cross section of the sheet.

In Figs. 3-8, portions of the first layer 100 shrink the second layer 200 relative to the first layer 100. This shrinkage provides the macroscopically three-dimensional surface of the first layer 100 as illustrated in FIG. 3-8. Similarly, third layer 300 may be shrinkable from second layer 200 to provide third layer 300 with a macroscopically three-dimensional surface.

The three-dimensional surface of the first layer 100 has relatively high peaks 105 and relatively depressed valleys 107. The third layer has peaks 305 and valleys 307. In Fig. 4, the peaks of layer 100 are indicated by reference numerals 105A and 105B, and the valleys of layer 100 are indicated by reference numerals 107A and 107B. Similarly, the peaks of layer 300 are marked 305A and 305B and the valleys are marked 307A and 307B. The peaks 105 provide elongated protrusions 120 on the outer surface of the first layer 100 and the peaks 305 provide elongated protrusions on the outer surface of the third layer 300.

The macroscopic three-dimensionality of the outer surface of the first layer 100 can be described in terms of the "mean differential height" of an adjacent peak and valley, as well as in terms of the "mean peak spacing" between adjacent peaks. The differential height with respect to the peak pair 105A / valley 107A is the distance H in FIG. 4. The distance between peaks between an adjacent pair of peaks 105A and 105B is indicated as the distance D in FIG. 4. The "mean differential height" and "mean peak distance" of the blade are measured as described later in "Test methods." The "surface topography index" of the exterior surface is the ratio obtained by dividing the average differential height of the surface by the average distance between peaks of the surface.

It will be apparent to one of ordinary skill in the art that there will be relatively small regions of peaks and valleys that are not significant enough to be considered to provide macroscopic three-dimensionality. For example, such regions may exist in the element (s) that eventually contract, for example, an elastic material to provide three-dimensionality. Again, these types of fluctuations and variations are a normal and expected result of the manufacturing process and are not considered when measuring the surface topography index.

Without wishing to be bound by theory, the surface topography index is believed to be a measure of the efficiency of the macroscopically three-dimensional surface in receiving and containing material in the valleys of the surface. A relatively high value of the mean height differential for a given mean distance between peaks provides deep and narrow valleys that can trap and hold materials. Therefore, it is believed that a relatively high value of the surface topography index indicates an effective capture of the materials during cleaning.

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The cleaning sheets of the present invention are characterized in that parts of the filaments 220, parts of the filaments 240, or parts of both filaments 220 and 240 of the second layer 200 are not attached to the first layer 100. In Fig. 4 , a portion of a filament 220 that extends between the intersections of filament 260A and 260B is not attached to first layer 100. The portion of filament 220 that is not attached to first layer 100 is indicated by reference numeral 220U. A gap between the filament 220 and the first layer 100 provides an empty space 180 between the first layer 100 and the filament 220. Similarly, portions of the filament 220 that extend between the intersections of the filament 260 are not bonded to the third layer. 300, thus providing an empty space 380 between the third layer 300 and the filament 220.

Figs. 7 and 8 also illustrate this feature of sheet 20. In Fig. 7, elongated protrusions 120 and 320 are visible on the outer surfaces of the first and third layers 100, 300, respectively. In Fig. 8, a filament 220 is seen extending between two intersections 260 of a filament. The part of the filament that extends between the two intersections of the filament is separated from, and not attached, to the first layer.

The bumps 120 are shown in plan view in Fig. 3 and Fig. 5. At least some of the bumps 120 extend along at least one strand of the second layer 200. In Fig. 4 , the bulge 120 corresponding to peak 105A extends through at least one filament 220.

Because the protrusions extend through one or more filaments, the protrusions may have a length greater than the maximum distance between the intersections of adjacent filaments 260 (the distance between the intersections of adjacent filaments after contraction of layer 200 and shrinkage of layers 100 and 300). In particular, the length of the protrusions 120 may be greater than the maximum dimension of the openings 250 in Fig. 1 (ie, greater than the length of the diagonal extending along the rectangular openings 250). The length of a bulge 120 is indicated by the letter L in Fig. 3. The length L is the distance in a straight line between two ends of a bulge 120, the ends of the bulge 120 being those points where a bulge 120 ends in a valley 107.

The value of L may be at least about 1.0 centimeters, more particularly at least about 1.5 centimeters for some of the protrusions 120. In one embodiment, at least some of the protrusions 120 have a length L of at least about 2 , 0 centimeters. The length L can be at least twice the distance between the intersections of adjacent filaments.

For example, in order to determine the length of the protrusions 120 relative to the distance between the intersections of adjacent filaments, the cleaning sheet 20 can be moistened and positioned on a lighted table or other suitable source of backlighting. Such backlighting, in combination with moistening the wiper sheet, can be used to make the intersections between filaments of layer 200 visible through layer 100 so that the lengths of the bumps 120 relative to the distance between the Strand intersections can be measured with a scale.

The elongated edges provide soft and deformable cleaning elements that allow better removal of the material from the surface to be cleaned. In contrast, if the second layer filaments were continuously attached to the first and second layers, then any of the first and third layer texture features would be confined to the area associated with the openings 250 of the second layer 200.

At least some of the elongated edges extend in a different direction from at least some of the other edges. In Fig. 3, the protrusions 120A, 120B, and 120C each extend in a different direction. Therefore, the blade is effective in catching material when the blade is used to clean in different directions.

Figs. 3 and 6 also illustrate that at least some of the protrusions 120 may have branches that extend in different directions. Shown in Fig. 3 is a bulge 120 having three branches 123A, 123B, and 123C extending in different directions. In the same way, Fig. 6 shows a bulge 120 having at least three branches designated 123A, 123B and 123C.

The first layer 100 and the third layer 300 are securely bonded to the second layer 200 at the intersections of the filament 260. Fig. 9 illustrates the bonding of the fibers from both layers 100 and 300 to the second layer at the intersection of the filament 260.

In Figs. 4, 7 and 8, the peaks 105 of the first layer 100 are generally offset from the peaks 305 of the third layer in the plane of the sheet 20. For example, in Fig. 4 the peak 305A of the third layer does not it is directly below peak 105A, but is generally aligned with the valley 107A associated with peak 105A. Thus, the peaks 105 of the first layer are generally aligned with the valleys 307 of the third layer and the peaks 305 of the third layer are generally aligned with the valleys 107 of the first layer.

The present invention also includes a method of manufacturing multilayer cleaning sheets. A first non-woven layer is provided, a second layer comprising a network-like filament arrangement and a third non-woven layer. The first layer is positioned adjacent to an upper surface of the second layer in an opposing relationship with the second layer. The third layer is positioned adjacent to a lower surface of the second layer, in opposing relationship with the second layer.

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The first layer and the third layer are then intermittently attached to discrete separate parts of the second layer, so that the portions of the filaments that extend between the intersections of the filaments remain unbound to the first layer and so that the portions of the filaments that extend between the intersections of the filaments remain unbound to the third layer. The second layer is contracted relative to the first layer and the third layer providing a retracted macroscopically three-dimensional outward-facing surface of the first layer and a retracted, outward-facing macroscopically three-dimensional surface of the third layer. The binding and contraction stages can occur simultaneously or sequentially.

The step of intermittent bonding of the second layer to the first layer and the third layer may comprise the step of heat pressing the first layer, the second layer and the third layer with a relatively low pressure for a relatively short period of time to avoid the relatively continuous bonding of the second layer to the first and third layers.

In one embodiment, the three layers can be joined using a BASIX B400 hand press manufactured by HIX Corp. of Pittsburg, Kansas. The three layers are joined by compressing them in the hand press, at a temperature of approximately 165.6 ° C (330 ° F), for approximately 13 seconds. The hand press has an adjustment to vary the clearance and consequently the pressure delivered in the press. The setting can be varied as desired to provide the desired texture at layers 100 and 300.

The invention also comprises packages containing cleaning sheets, with the packages associated with information that will inform the consumer, through texts and / or images, that the use of the sheets will provide cleaning benefits that include the removal and / or trapping of dirt. (eg, dust, lint, etc.) and this information may comprise a claim of superiority over other cleaning products. In a highly desirable variation, the package carries information that informs the consumer that use of the cleaning sheet provides reduced levels of dust and other airborne matter present in the atmosphere. It is very important that the consumer is advised of the possibility of using the sheets on non-traditional surfaces, including fabrics, pets, etc. to ensure that all the benefits of the leaves are taken advantage of. Therefore, it is important to use the packaging together with the information that informs the consumer, through text and / or images, that the use of the compositions will provide advantages such as better cleaning, the reduction of dirt in the form of particles in the air, etc. as described herein. The information may include, p. For example, the advertisement in all the usual media, as well as statements and icons on the packaging or on the sheet itself to inform the consumer.

The above products that do not comprise the preferred structures of the present invention may be used to provide the benefits to a lesser degree and to the extent that these benefits have not been previously recognized, they should be included in the information provided. Otherwise, the consumer will not get the full value of the improved performance compared to conventional products or practices.

III. Cleaning tools

In another aspect, the present invention relates to a cleaning implement comprising the cleaning sheets described above. In this regard, the cleaning implement comprises:

to. a handle; Y

b. a removable cleaning sheet having a first surface and a second surface, the mean distance between peaks being 4 to 12 mm and the surface topography index being from about 0.01 to about 5.

The implement, and separately, the cleaning sheet of the present invention are designed to be compatible with all hard surface substrates, including wool, vinyl, linoleum, non-wax-containing floors, ceramic, Formica®, porcelain, and the like.

The handle of the cleaning implement comprises any durable elongated material that provides ergonomically convenient cleaning. The length of the handle will be dictated by the application that is given to the utensil.

The handle will preferably comprise at one end a support head to which the blade can be detachable. To facilitate the use of the utensil, the support head can be fixed to the handle so that the said head can be pivoted by known connecting elements. Any suitable fastening material can be used to secure the cleaning sheet to the support head as long as the cleaning sheet remains attached during the cleaning process. Examples of suitable fastening materials include clamps, hooks, and counter hooks (eg, VELCRO®), and the like. In a preferred embodiment, the support head will comprise materials to hold the sheet on its upper surface and keep the sheet mechanically attached to the head during cleaning work. However, the fastening material will allow the blade to be easily released for convenient replacement and removal.

The cleaning sheets useful in the cleaning implement of the present invention are those described above.

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IV. Test methods

A. Average height differential

The mean height differential is determined using an optical microscope (eg, Zeiss Axioplan, Zeiss Company, Germany) equipped with a device for measuring the Z dimension (eg, Microcode II, sold by Boeckeler, Instruments ). This procedure involves locating a peak or trough region of the leaf, focusing the microscope, and zeroing the Z-dimension measuring device. The microscope is then moved to an adjacent valley or peak region, respectively, and the microscope is refocused. The instrument display indicates the difference in height between this peak / valley or valley / peak pair. This determination is repeated at least 10 times, at random locations on the leaf, the mean differential height being the average of these determinations.

B. Distance between peaks

Simple light microscopy can be used to measure the distance between peaks. The magnification used should be sufficient to easily measure the distance between two adjacent peaks. This determination is repeated at least 10 times, at random locations on the sheet, the average distance between peaks being the average of these determinations.

C. CD elongation with 500 g

CD elongation is a measure of the percent elongation exhibited by a test sample with a load of 500 g. CD elongation can be measured using a Sintech Renew Instron 7310 (including Testworks software package) with a 100N load cell. Using this instrument, a Load vs.% Voltage curve is generated. The test parameters are as follows:

Sample width = 30 mm

Reference length = 100 mm

Crosshead speed = 300 mm / min

From the generated curve, the software obtains the% tension (% elongation) with a load of 500 g, which is recorded as CD elongation with 500 g.

V. Representative examples

The following are illustrative examples of the cleaning sheets of the present invention. The reinforced three-dimensionality is indicated in Table I.

Example 1

This example illustrates the combination of carded fabrics and a mesh (ie, a polypropylene filament net) to make a cleaning sheet of the present invention. Two polyester carded fiber fabrics are prepared with a mesh between them. The combination of the two carded fabrics and the mesh are then placed on top of an apertured forming belt (N 50 flat squares) and hydroentangled and dried. The water entangling process causes the fibers to become entangled and also to bond with the mesh, causing the fibers to separate and provide two different weight regions per unit area. During the drying process, the hydroentangled sheet becomes "cushioned" (ie, greater three-dimensionality is achieved) as a result of the shrinkage of the polypropylene mesh relative to the nonwoven polyester. As a preferred optional step, the nonwoven sheet is surface coated (eg, by printing, spraying, etc.) with 5% by weight of a 1: 1 mixture of mineral oil and paraffin wax. The bonded nonwoven sheet is subjected to further heating, eg, in a press at 180 ° C for 10 sec, to provide a greater degree of three-dimensionality. This sheet is referred to as Example 1 in Table 1. (This heating can be done before or after adding the optional surface treatment, but is preferably done before application of the additive.) This additional heating provides an even more enhanced three-dimensionality.

Example 2

A cleaning sheet according to the present invention includes a first layer 100, a second layer 200, and a third layer 300. The first layer 100 and third layer 300 each comprise a hydroentangled fabric of polyester fibers having a basis weight of about 30 grams per square meter. The second layer comprises the THERMANET® brand reinforcing mesh described above having a two-sided polypropylene / EVA resin adhesive and a filament number of 3 filaments per 2.5 cm (per inch) by 2 filaments per 2.5 cm. (per inch) before second layer shrinkage. The second layer 200 is placed between the first layer

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100 and the third layer 300 on a BASIX B400 manual press. The three layers are joined by compressing them in the hand press, at a set temperature of approximately 165.6 ° C (330 ° F), for approximately 13 seconds.

In Table I the measured values ​​of mean peaking distance, mean differential height and surface topography index of the cleaning article are presented.