USEFUL THREE-DIMENSIONAL STRUCTURES LIKE CLEANING SHEETSFIELD OF THE INVENTIONThis 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 INVENTIONIt is known in the art to use non-woven sheets to clean dry dust. Almost always, said sheets use a mixed material of fibers in which they are joined by adhesive, entanglement or other forces. See, for example, US patent. No. 3,629,047 and patent of E.U.A. No. 5,144,729. To provide a durable cleaning sheet, reinforcing means have been combined with staple fibers in the form of a continuous network or filament structure. See, for example, US patent. No. 4,808,467, patent of E.U.A. No. 3,494,821 and US patent. No. 4,144,370. Also, to provide a product capable of withstanding the rigors of the cleaning process, the above non-woven sheets have employed fibers strongly bonded by one or more of the aforementioned forces. Although durable materials are obtained, said firm bond can adversely impact the ability of the material to collect and retain dirt in particles. In an effort to address this issue, US patent. 5,525,397 to Shizuno et.al, discloses a cleaning sheet that includes a polymeric network layer and at least one nonwoven layer, wherein the two layers are slightly hydroentangled to provide a sheet having a low coefficient of entanglement. It is said that the resulting sheet provides strength and durability, as well as the performance improvement when collecting dust, since the fibers of mixed material are slightly hydroentangled. It is said that sheets that have a low coefficient of entanglement (ie not greater than 500 m) offer better cleaning performance, since a greater number of fibers are available to make contact with the dirt. Although it is claimed that the sheets described in the '397 patent are directed to some of the problems presented by the above non-woven cleaning sheets, in general, those sheets appear to have a uniform basis weight, at least at a macroscopic level; and in essence, they are of a uniform caliber, once again, on a macroscopic level. That is to say that fluctuations and expected and ordinary variations can occur based on the weight and caliber at random, as a result of differences in the fluid pressure during the hydroentanglement. However, the structure would not be intended to include discrete regions that differ with respect to weight. For example, if it is a microscopic level, the basis weight of a gap between the fibers is measured, and would result in an apparent basis weight of zero, in fact, unless an opening in the non-woven structure has been measured. , the base weight of said region is greater than zero. These fluctuations and variations are a normal and expected result of hydroentangling procedures. The person skilled in the art would interpret the non-woven structures with such variations, including those described in the '397 patent, in essence, as if they had a uniform gauge and basis weight, in the macroscopic sense. The result of a sheet having a uniform basis weight is that the material is not suitable in particular to pick up and trap dirt of various size, shape, etc. As such, there is a continuing need to provide cleaning sheets that offer better dirt removal. In this regard, applicants have discovered that by providing an increase in three-dimensionality, in the macroscopic sense, for the cleaning sheets, a better removal of the dirt is achieved. Therefore, it is an object of this invention to overcome the problems of the prior art and in particular to provide a structure with greater capacity to eliminate and trap various types of dirt. SpecificallyIt is an object of this invention to provide a non-woven structure having an important three-dimensionality, which is described in more detail below. Another objective is to provide improved cleaning procedures, as well as desirable benefits for the consumer and user of the sheets, especially by packing the sheets, either in the form of a roll, with perforations to separate the sheets or means for separating the sheets into useful lengths , and placing them in packages that inform the consumer of the improvement in the procedures and / or the benefits that can be obtained, especially the benefits that are not obvious to the consumer's intuition. Another objective is to provide cleaning sheets with additives, especially those that improve the adhesion of the dirt to the substrate, and especially for the sheets described hereinafter with three-dimensional structure, said combinations having special performance benefits and offering improved benefits.
BRIEF DESCRIPTION OF THE INVENTIONThe present invention relates to a cleaning sheet having a substantial macroscopic three-dimensionality. As used herein, the term "macroscopic three-dimensionality", when applied to describe three-dimensional cleaning sheets, means that the three-dimensional pattern is visible to the naked eye when the perpendicular distance between the user's eye and the plane of the sheet is 30.5 cm. In other words, the three-dimensional structures of the present invention are cleaning sheets that are not flattened where one or both surfaces of the sheet are in multiple planes, where the distance between the planes can be observed with the naked eye when the structure is appreciated from approximately 30.5 cm. By way of contrast, the term "flattened" refers to cleaning sheets that have very thin surface imperfections on one or both sides, imperfections of the surface can not easily be seen with the naked eye when the perpendicular distance between the The user's eye and the plane of the tape is about 30.5 cm or greater. In other words, in a macroscale, the observer would not see that one or both surfaces of the sheet are in multiple planes to be three-dimensional. The macroscopically three-dimensional surfaces of the present invention optionally include a canvas material that upon heating and then cooling contracts to provide a macroscopic three-dimensional structure. Other materials that can provide contraction forces to provide a three-dimensionality are explained below. In the present, the macroscopic tridimensionality is described as a function of the "average weight differential", which is defined herein as the average distance between the adjacent peaks and valleys of a given surface of a sheet, as well as the distance "peak to average peak ", which is the average distance between the adjacent peaks of a given surface. The macroscopic three-dimensionality is also described in terms of the "surface topography index" of the external surface (s) of the cleaning sheet; the surface topography index is the ratio obtained by dividing the average weight differential of a surface by the average peak-to-peak distance of that surface. In one embodiment, both outer surfaces of the sheet will have the described properties of average peak to peak distance and surface topography. The methods for measuring the average peak-to-peak distance and the average height differential are written later in detail in the section entitled Test Method. The average peak-to-peak distance of at least one external surface will be at least about 1 mm, more preferably at least about 2 mm, and more preferably at least about 3 mm. In one embodiment, the average peak-to-peak distance is from about 1 to about 20 mm, in particular from about 3 to about 16 mm, more particularly from about 4 to about 12 mm. The surface topography index of at least one external surface will be from about 0.01 to about 10, preferably from about 0.1 to about 5, still more preferably from about 0.2 to about 3, and still more preferably from about 0.03 to about 2. Although the value of the average height differential is not decisive, at least one external surface preferably will have an average height differential of at least about 0.5 mm, more preferably at least about 1 mm and with greater preference still of at least about 1.5 mm. The average height differential of at least one external surface will almost always be from 0.5 to about 6 mm, more often from about 1 to about 3 mm. The sheets of this invention and similar sheets, especially those containing additives at low levels, are described herein, and especially those where the additive adheres substantially uniformly over at least one continuous area, can be employed in improved procedures for cleaning and providing benefits desirable to the consumer and user of the sheets, some of those benefits are not apparent to the consumer's intuition, as described in detail hereinafter. Therefore, it is desirable to pack the sheets, either in the form of a roll, with perforations to assist in separating the sheets, or with means for separating the sheets into useful lengths, and / or placing them in packages that inform the consumer of improved procedures. and / or the benefits that can be obtained, especially the benefits that are not obvious to the consumer. Cleaning sheets with additives, including those having desirable low levels of said additives, preferably substantially uniformly adhered to, at least in one or more areas, provide in combination special performance benefits, and said combinations can provide improved benefits, especially when the sheets have the desirable structures mentioned hereinabove.
BRIEF DESCRIPTION OF THE DRAWINGSFigure 1 is a schematic plan perspective illustration of a three layer embodiment of a cleaning sheet of the present invention, wherein the second layer includes a canvas material having filaments that are parallel to the side and end edges of the sheet, wherein a portion of the first layer is cut away, and wherein the characteristics of the surface of the first layer are omitted to illustrate more clearly. Figure 2 is an illustration of the type shown in Figure 1 depicting an alternative embodiment of the present invention wherein the filaments of the second layer are inclined at an angle of 45 degrees.áíi í ..approximately in relation to the side; ^ the final edges of the cleaning sheet. Figure 3 is a schematic plan perspective illustration of the photograph of Figure 5 showing the texture of the macroscopically three dimensional outer surface of the first layer, and in particular the ridges on the outer surface of the first layer. Figure 4 is a cross-sectional illustration of the sheet, taken in a position parallel to one of the filaments of the second layer and showing the portions of the filament extending at the intermediate intersections of filaments, the portions of the filaments not they are attached to the first layer, as well as the portions of the filaments that extend at the intermediate intersections of filaments that are not attached to the third layer. Figure 5 is a photomicrogram showing the texture of the macroscopically three-dimensional surface of the first layer, and in particular, the elongated ridges of the surface. The scale of figure 5 is in centimeters. Figure 6 is an amplified photomicrogram of the type illustrated in Figure 5 showing an elongated ridge with branches extending in different directions. Figure 7 is an Electronic Scanning Micrograph that offers a perspective view of the macroscopically three-dimensional surface of the first layer.
FIG. 8 is an Electronic Scanning Micrograph of a cross section of the cleaning sheet showing the portions of the filaments extending at the intermediate intersections of filaments, the portions of which of the filaments are not attached to the first layer. Figure 9 is an Electronic Scanning Micrograph showing the joining of the first and third layers with the second layer at the intersections of filaments.
DETAILED DESCRIPTION OF THE INVENTIONI) Definitions As used herein, the term "including" means that the various components, ingredients or steps may be used together in the practice of this invention. Accordingly, the term "including" includes the more restrictive terms "consisting essentially of" and "consisting of". As used herein, the term "hydroentanglement" generally means a process for making a material in which a layer of loose fibrous material (e.g., polyester) rests on an open pattern forming element and is subject to differentials. of water pressure high enough to cause the individual fibers to entangle mechanically to produce a fabric. The open pattern forming element can be made, for example, from a woven mesh, a perforated metal plate, etc. As used herein, the term "Z dimension" refers to the orthogonal dimension across the width of the cleaning sheet of the present invention or a component thereof. As used herein, the term "X-Y dimension" refers to the plane orthogonal to the thickness of the cleaning sheet, or a component thereof. In general, the dimensions X and Y correspond to the length and width, respectively, of the sheet or a component of the sheet. As used in this, the term "layer" refers to an element or component of a cleaning sheet whose primary dimension is X-Y, that is, by its length and width. It should be understood that the term "layer" is not necessarily limited to isolated layers or sheets of material. Therefore, the layer may encompass laminates or combinations of various sheets or networks of the required type of materials. Therefore, the term "layer" includes the terms "layers" and "layers". For purposes of the present invention, an "upper" layer of a cleaning sheet is a layer that is relatively far from the surface to be cleaned (i.e., in the context of the implement, relatively close to the implement handle during use). ). On the contrary, the term "lower" layer means a layer of a cleaning sheet that is relatively close to the surface to be cleaned (i.e., in the context of the implement, with relative distance from the implement handle during use).
All percentages, ratios and proportions used herein are by weight unless otherwise specified. II Cleaning sheets The present invention relates to a cleaning sheet useful for removing dust, lint, hair, grass, sand, food crumbs and other matter of varying size, shape, consistency, etc. from a variety of surfaces . Preferably, the cleaning sheets will demonstrate an improvement in cleaning performance in panel tests for consumers. As a result of the ability of the cleaning sheets to reduce or eliminate, through various means, including contact and retention of dust, lint and other airborne, surface and airborne matter, the sheets will provide a great reduction in the levels of said materials in surfaces and in the atmosphere, in relation to other products and practices for similar cleaning purposes. This ability is evident especially in sheets containing additives, as described herein. Even the sheets of the US patent. 5,525,397, incorporated hereinbefore, can provide this benefit, although to a lesser degree than the preferred structures in this invention, and therefore, it is important to provide this information in the package, or in relation to the package, to promote the use of the sheets, including those of the '397 patent mentioned, especially on unusual surfaces, such as walls, ceilings, tapestries, curtains, rugs, garments, etc., where the dust-cleaning sheets have not been used normally. The use of a low level of additive, uniformly adhered in at least one area, preferably continuous, of the sheet in an amount effective to improve the adhesion of dirt, especially particles, and especially those particles that cause allergic reactions, provides a surprising level of control over the adherence of dirt. At least in those areas where the additive is found in the sheet, the low level is important for that use, since, despite traditional powder formation operations where oils such as liquids or aerosols are applied, there is much less damage to create a visible stain, especially on unusual surfaces where the sheet is used. Preferred structures also offer benefits by trapping large particles instead of crumbling them into small pieces. Consumers with allergies benefit in particular from the use of the sheets of this invention, especially the preferred structures, since allergens are almost always in the form of a powder and it is desirable in particular to reduce the level of small particles that are breathed. To achieve this benefit it is important to use the sheets regularly and not only when the grime becomes apparent, as in the prior art process. The cleaning sheets of the present invention may be made using a knitting or non-woven process, or by forming operations using mixed materials placed on shapes, especially in strips, and / or by forming operations related to mechanical actions / modifications carried out on films. The structures are elaborated by means of a series of methods, once the essential three-dimensional requirements are known. However, the structures* - * - - ----- ^^ i- sMz ¿¿¡¡¡¡¡¡¡¡¡Preferred are not woven and especially those that are formed by hidroenmarañamiento as well known in the art, since they provide extremely open structures desirable Therefore, the preferred cleaning sheets useful herein are non-woven structures having the characteristics described herein. Particularly suitable materials for forming the preferred nonwoven cleaning sheet of the present invention include, for example, natural, as well as synthetic, celluloses, such as polyolefins (e.g. polyethylene and polypropylene), polyesters, polyamides, synthetic celluloses (for example RAYON®), and mixtures thereof. Natural fibers, such as cotton or mixtures thereof, and those derived from various sources of cellulose are also useful. Preferred starting materials for making the hydroentangled fibrous sheets of the present invention are synthetic materials, which may be carded, spunbonded, meltblown, airlaid or other structures. Particular preference is given to polyesters, in particular carded polyester fibers. The degree of hydrophobicity or hydrophilicity of the fibers is optimized depending on the desired objective of the sheet, depending on the type of dirt that will be removed, the type of additive that is provided, when an additive is present, biodegradability, availability and combinations of these considerations. In general, the most biodegradable materials are hydrophilic, but the most effective materials tend to be hydrophobic. The cleaning sheets can be formed from a single fibrous layer, but preferably they are a mixed material of at least two separate layers. Preferably, the sheets are nonwoven structures made by a spinning process. In this regard, prior to the hydroentangling of the discrete layers of fibers there is the possibility of lightly entangling each of the layers before joining them by entanglement. In a particular preferred embodiment of the present invention, to improve the integrity of the final sheet, it is preferred to include a polymeric network (referred to herein as a "canvas" material) that is placed with the fibrous material, for example, although be lamination by heat or chemical means, such as adhesives, through hydroentanglement, etc. Canvas materials useful herein are described in detail in the U.S.A. No. 4,636,419, which is incorporated herein by reference. The canvases can be formed directly on the extrusion die or can be derived from films extruded by fibrillation or enhancement, followed by stretching and separation. The canvas can be derived from a polyolefin, such as polyethylene or polypropylene, copolymers thereof, polybutylene terephthalate, polyethylene terephthalate, Nylon 6, Nylon 66 and the like. The canvas materials are available in different commercial sources. A preferred canvas material useful in the present invention is a polypropylene sheet, made by Conwed Plastics (Minneapolis, MN). In another aspect of the present invention, applicants have also discovered that incorporation of the canvas material into a cleaning sheet, followed by heating, provides a three-dimensional macroscopic feature to the sheet. It has been found that this macroscopic three-dimensionality greatly improves the cleaning performance of the cleaning sheet, even where the base weight of the sheet is essentially uniform. In particular, macroscopic tridimensionality is achieved when the mixed canvas / fiber material is subjected to heating and then cooling. This procedure results in a shrinkage (in the X-Y dimension) of the canvas and, as a result of bonding with the fibers, provides a sheet with greater three-dimensionality. The degree of added three-dimensionality is controlled by the level of heating applied to the canvas / cleaning combination. The inclusion of a canvas is beneficial in particular when the fiber aspect of the structure is a non-woven, particularly when the structure is hydroentangled. In this aspect, the invention relates to macroscopically three-dimensional cleaning sheets. These sheets are preferably relatively open structures compared to, for example, paper towels. In a preferred embodiment, the macroscopically three-dimensional cleaning sheets have a first surface and a second surface and include a linen material. In said preferred embodiment, the cleaning sheet has a first outward surface and a second outward surface and includes a canvas material, wherein the average peak to peak distance of at least one outward surface is at least about 1 mm and that of the The surface topography index of that surface (s) is from about 0.01 to about 5.
Regardless of the configuration of the cleaning sheets, the peak, peak, average distance of at least one outward surface will be at least about 1 mm, more preferably at least about 2 mm, and even more preferably at least about In one embodiment, the average peak-to-peak distance is from about 1 to about 20 mm, particularly from about 3 to about 16 mm, more particularly from about 4 to about 12 mm. Surface topography of at least one outward surface will be from about 0.01 to about 10, preferably from about 0.1 to about 5, more preferably from about 0.2 to about 3, with even greater preference from about 0.3 to about 2. Although not decisive, at least one outward surface preferably will have an average height differential of at least about 0.5 mm, with greater preference about 1 mm at least, and more preferably at least about 1.5 mm. The average height differential of at least one outward surface will almost always be from about 0.5 to about 6 mm, more often still from about 1 to about 3 mm. Again with respect to the macroscopic three-dimensional cleaning sheets of the present invention, these structures will offer an improved prolongation, particularly in the CD direction, which will improve the formability, either when used as an isolated product or when used in combination with a cleaning implement. In this regard, the macroscopically three-dimensional sheets will preferably have a CD extension value in 500 g of at least about 3%, more preferably about 6% at least, more preferably about 10% at least, with greater preference still around 15% at least, and even more preferably 20%. The cleaning performance of any of the cleaning sheets of the present invention can also be improved by treating the fibers of the sheet, in particular, surface treatment, with any of several additives, including surfactants or lubricants that improve the adhesion of dirt to the sheet. When used, said additives are added to the cleaning sheet at a level sufficient to improve the ability of the sheet to adhere dirt. Preferably, said additives are applied to the cleaning sheet at an addition level of about 0.01% at least, more preferably at least 0.1% at least, more preferably at around 0.5% at least, with greater preferably at least about 1%, more preferably at least about 3%, even more preferably at least about 4% by weight. Almost always, the level of addition ranges from about 0.1 to about 25%, more preferably from about 0.5 to about 20%, more preferably from about 1 to about 15%, with even more preference from about 3 to about of 10%, even more preferably from about 4 to about 8% and much more preferably from about 4 to about 6%, by weight. A preferred additive is a wax or a mixture of an oil (eg, mineral oil, petroleum jelly, etc.)^ \ r * ^ *, and a wax. Suitable waxes include various types of hydrocarbons, as well as esters of certain fatty acids (for example, saturated triglycerides) and fatty alcohols. They can be derived from natural sources (ie, animal, vegetable or mineral) or they can be synthesized. The mixtures of the various waxes can also be used. Some representative animal and vegetable waxes that may be used in this invention include beeswax, carnauba, spermaceti, lanolin, shellac, candelilla and the like. Representative waxes from mineral sources that can be used in this invention include waxes from petroleum, such as paraffin, petrolatum and microcrystalline wax, as well as terrestrial or fossil waxes, such as white ceresin wax, yellow ceresin wax, white ozokerite wax, and the like. Representative synthetic waxes that can be employed in the present invention include ethylene polymers, such as polyethylene wax, chlorinated naphthalenes, such as "Halowax", hydrocarbon type waxes made by Fischer-Tropsch synthesis, and the like. When a mixture of mineral oil and wax is used, the components will preferably be mixed in an oil to wax ratio of about 1: 99 to about 7: 3, more preferably from about 1: 99 to about 1: 1. , still more preferably from about 1: 99 to about 3: 7 by weight. In a particular preferred embodiment, the ratio of oil to wax is about 1: 1, by weight, and the additive is applied at an addition level of about 5% by weight. A preferred mixture is a 1: 1 mixture of mineral oil and paraffin wax.
In particular, an improvement in cleaning performance is achieved when the macroscopic three-dimensionality and the additive are applied in a single cleaning sheet. As already mentioned, these low levels are desirable particularly when the additives are applied at an effective level and preferably in a substantially uniform manner in at least one discrete continuous area of the sheet. The use of lower preferred levels, especially additives that improve the adherence of dirt to the sheet, surprisingly provides good cleaning, elimination of dust in the air, preferred impressions in the consumer, especially tactile impressions and, in addition, the additive it can provide a means for incorporating and adhering perfumes, pest control ingredients, antimicrobials, including fungicides, and a carrier of other beneficial ingredients, especially those that are soluble, or can be dispersed, in the additive. The benefits are only by way of example. Low levels of additives are desirable especially where the additive can have adverse effects on the substrate, the package and / or the surfaces being treated. The application medium for these additives preferably applies at least a substantial amount of the additive at points on the sheet that are "inside" the structure of the sheet. Is a special advantage of the three dimensional structures that the amount of additive that is in contact with the surface to be treated, and / or package, is limited, so that materials that contrary, would cause damage or interfere with the function of the other surface, they can only cause limited adverse effects or not. The presence of the additive within the structure is very beneficial, since the dirt adhering inside the structure is less likely to be removed by a subsequent cleaning action. Figure 1 illustrates a multi-layer cleaning sheet 20 in accordance with the present invention. The cleaning sheet 20 includes side edges 22 and end edges 24. The side edges 22 generally extend parallel to the length of the sheet 20 and the end edges 24 generally extend parallel to the width of the sheet . Optionally, the sheet 20 may include an edge seal 26 that extends around the perimeter of the sheet. Said edge seal 26 can be formed by heating, by the use of adhesives, or by a combination of heating 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 positioned between the first layer 100 and third layer 300. In the Figure 1, a portion of the first layer 100 is shown cut away to illustrate the implied portions of the second layer 200 and the third layer 300. The first layer 100 can be formed from woven materials, non-woven materials, paper tapes, foams , wadding and the like, as known in the art. Preferred materials in particular are non-woven ribbons having fibers or filaments randomly distributed as the "laying in air" or "wet laying" method, or with a degree of orientation, as in certain "wet laying" processes. and "cardeo." The fibers orl-? ^ & - '.. * _ £ -s filaments of the first layer 100 can be natural or natural origin (e.g. cellulosic fibers such as wood pulp fibers, cotton fibers residue, rayon fibers of bagasse) or synthetic (for example polyolefins, polyamides or polyesters). The third layer 300 may be the same substantially as the first layer 100, or alternatively, may be of a different material and / or construction. In one embodiment, the first layer 100 and third layer 300 may include, each, a hydroentangled nonwoven tape with a lower denier synthetic to about 4.0, preferably less than about 3.0, more preferably less than about 2.0 g, per 9000 m fiber length. A suitable first layer 100 (as well as a suitable layer 300) is a hydroentangled ribbon of polyester fibers with a denier of about 1.5 g or less per 9000 m fiber length, and the belt has a basis weight of about 30 g per meter square. PGI Nonwovens of Benson, N.C. produces a suitable tape, under the designation PGI 9936. The second layer 200 is discontinuously joined to the first layer 100 (and the third layer 300, if present), and applies a retraction of the first layer by contraction of the second layer. cap. The contraction mechanisms include, but are not limited to, elastic and contraction properties by heating the second layer. As already mentioned, in said embodiment, the second layer 200 includes a placement similar to a network of filaments with holes defined by adjacent filaments. Alternatively, the second layer may be in the form of a polymeric film, whichfc can optionally have holes in the entire area; to provide the contraction mechanism that is required, said films must have sufficient elasticity to apply the folding function that gives rise to the three-dimensional surface. The film can be raised to cause depressions in the surface instead of and in addition to the holes. In another alternative, the contractile effects can be generated by the inclusion of fibers that contract when heated and cooled. In this aspect, certain fibers will not shrink, but since they are mechanically related to the fibers that can shrink, the entire sheet will "shrink" as the shrinkable fibers contract, as long as said fibers are included in a sufficient level. In the illustrated embodiments, the second layer includes a placement similar to a filament network that includes a first plurality of filaments 220 and a second plurality of filaments 240. The filaments 220 generally extend parallel to each other, and the filaments 240 they generally extend in a parallel position to each other and usually perpendicular to the filaments 220. The filaments extend between the intersections of filaments 260. The adjacent intersecting filaments 220 and 240 define the holes 250 in the second layer 200. The intersections of filaments and holes 250 are usually placed in a pattern similar to a uniform repeating grid. The second layer 200 may include a polymer network (hereinafter referred to as "canvas material"). Suitable canvas materials are described in the US patent. 4,636,419 incorporated herein by reference. The canvas may be derived from a polyolefin, such as polyethylene or polypropylene, or copolymers thereof, polybutylene terephthalate, polyethylene terephthalate, Nylon 6, Nylon 66 and the like, and mixtures thereof. Preferably, the canvas material is bonded to the layers 100 and 300 by lamination through chemical or heating means, such as adhesives. Preferably, the filaments of the canvas material are contracted relative to the layers 100 and 300 when heated, so that the contraction of the second layer 200 folds the layers 100 and 300 and prints a macroscopic three-dimensional texture to the outer surfaces of the layers. layers 100 and 300, as described in more detail below. A particularly suitable canvas material, and which is useful as the second layer 200, is a heating activated reinforcement mesh made by Conwed Plastics of Minneapolis, MN as THERMANET brand reinforcement mesh, which has a polypropylene / EVA resin, adhesive on both sides, and a filament density of 3 strands every 2.54 cm by 2 strands every 2.54 cm before shrinkage, such as by heating. After heating, the second layer 200 can have between about 3.5 to 4.5 strands every 2.54 cm by about 2.5 to 3.5 strands every 2.54 cm. The term "both side adhesive" means that the EVA adhesive(Ethyl-vinyl acetate adhesive) is found on both sides of the filaments. The EVA activation temperature is generally around 85 ° C (approximately 185 ° F). During the lamination of the layer 200 to the polyester fibers of the layers 100 and 300, the EVA adhesive is activated to cause the bond between the filaments of the layer 200 and the fibers of the layers 100 and 300. Without being limited to the theory , it is believed that the application of pressure at a relatively low pressure (for example, less than 3.51 kg / cm2 and more preferably less than 1.75 kg / cm2) for a relatively short time (less than about 30 seconds), the filaments of the layer 200 is not continuously bonded to the non-woven structures of the layers 100 and 300. This discontinuous joining together with the shrinkage of the polypropylene filaments upon heating provides an improved texture of the surfaces out of the layers 100 and 300 In figure 1, the filaments 220 generally extend parallel to the side edges 22 and along the sheet 20. Similarly, the filaments 240 generally extend parallel to the end edges 24 and the width of the sheet 20. Alternatively, the filaments 220 may be inclined at an angle between about 20 and about 70 ° with respect to the length of the sheet 20 and the side edges 22, and more preferably between about 30 ° and about 60 °. The filaments 240 may be inclined at an angle between about 20 and about 70 ° with respect to the width of the sheet 20 and the final edges 24, and more preferably between about 30 ° and about 60 °. Figure 2 shows an embodiment of the present invention, wherein the filaments 220 are inclined at an angle of approximately 45 °with respect to the side edges 22 (angle A in Figure 2), and wherein the filaments 240 are inclined at an angle of about 45 ° with respect to the end edges 24 (angle B in Figure 2). Said positioning offers the advantage that the orientation of the angle of the filaments 220 and 240 with respect to the length and width of the sheet 20 allows the deformation of the mesh structure of the layer 200 parallel to the edges 22 and 24. Blister deformation gives the sheet an almost elastic behavior parallel to the length and width of the sheet. "Nearly elastic behavior" means that the element in question can lengthen under tension in one direction to achieve an elongated dimension, measured in that direction, which is at least 120% of the original dimension at rest of the element in that direction, and also means that when releasing the tension to lengthen the element, it recovers in 10% of its dimension at rest. An important aspect of one embodiment of the present invention is that the first layer 100 is intermittently joined to the second layer 200. In particular, the first layer 100 may be intermittently joined to the second layer 200 at the intersections of filaments 260, while the portions of the filaments 220, the portions of the filaments 240, or the portions of both intermediate filaments 220 and 240 at the intersections of filaments 260, remain unbonded to the 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 holes in the placement almost.¿¡ & k in a network of the filaments, but is disconnected from the uniform geometry of repetition of the holes 250. Similarly, the third layer 300 may be intermittently joined to the second layer 200 to provide the surface texture similar to the external surface of third layer 300. The surface texture of first layer 100 is omitted in figures 1 and 2 to show greater clarity. The surface texture is illustrated in Figures 3-8. Figure 3 provides a schematic illustration of the surface texture of the first layer 100 appearing in the photograph of Figure 5. Figure 4 gives a cross-sectional illustration of the surface texture of the first layer 100 and the third layer 300. Figure 5 is a photomicrogram showing the texture of the macroscopically three-dimensional surface of the first layer 100. Figure 6 is a photomicrogram showing the three-dimensional surface of the first amplified layer 100. Figure 7 is a scanning electron micrograph that provides an overview of the three-dimensional surface of the first layer 100. Figure 8 is an electronic scanning micrograph of a cross section of the sheet. With respect to Figures 3-8, the portions of the first layer 100 are folded back by contraction of the second layer 200 relative to the first layer 100. This retraction gives the first layer 100 a macroscopically three-dimensional surface as shown in the figures 3-8. Similarly, the third layer 300 can be retracted by contraction of the second layer 200 to give the third layer 300 a macroscopically three-dimensional surface. The three-dimensional surface of the first layer 100 has relatively high peaks 105 and relatively flat valleys 107. The third layer has peaks 305 and valleys 307. In Figure 4, the peaks of the layer 100 are indicated with the reference numbers 105A and 105B , and the valleys of layer 100 are indicated with 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 ridges 120 on the outward surface of the first layer 100, and the peaks 305 provide elongated ridges 320 on the outward surface of the third layer 300. The macroscopic three-dimensionality of the outer surface of the first layer 100 may described according to the "average height differential" of a peak and an adjacent valley, as well as depending on the "average peak to peak distance" between the adjacent peaks. The height differential with respect to a peak torque 105A / valley 107A is the distance H in Figure 4. The peak-to-peak distance between an adjacent pair of peaks 105A and 105B is indicated as distance B in Figure 4. The " average height differential "and the" average peak to peak distance "for the sheet are measured as mentioned later in" test methods ". The "surface topography index" of the outward surface is the ratio obtained by dividing the differential of average height of the surface between the average peak-to-peak distance of the surface.
It will be apparent to the person skilled in the art that there will be relatively small regions of peaks and valleys that are not of sufficient importance to be considered as providing a macroscopic three-dimensionality. For example, said regions may exist in the element (s) that are finally contracted 5 by, for example, an elastic material to provide the three-dimensionality. Again, such fluctuations and variations are a normal and expected result of the processing procedure and are not considered when measuring the surface topography index. Without being limited to theory, it is believed that the topography index ofThe surface is a measure of the effectiveness of the macroscopically three-dimensional surface in receiving and containing the material in the valley of the surface. A relatively high value of the average height differential for a given average peak-to-peak distance produces narrow, deep valleys that can trap and retain matter. Therefore, it is believed that a relatively high value of thesurface topography indicates the effective capture of matter during cleaning. The cleaning sheets of the present invention possess the feature that the portions of the filaments 220, the portions of the filaments 240, or the portions of both filaments 220 and 240 of the second layer 200 are not attached to the first layer 100. With respect to figure 4, aThe portion of a filament 220 extending between the intersections of filaments 260A and 260B is not attached to the first layer 100. The filament portion 220 that is not attached to the first layer 100 is indicated by the reference numeral 220U. A space between the filament 220 and the first layer 100The "U" provides an intermediate hollow space 180 in the first layer 100 and the filament 220. Similarly, the portions of the filament 220 that extend between the intersections of filaments 260 are not bonded to the third layer 300, so they provide a hollow space 380 between the third layer 300 and the filament 220. 5 Figures 7 and 8 also illustrate this feature of the sheet 20.
In Figure 7, the elongated crests 120 and 320 are visible on the outward surfaces of the first and third layers 100, 300, respectively. In Figure 8, it is noted that a filament 220 extends between two intersections of filaments 260. The portion of filament extending between the twointersections of filaments is separated from, and not attached to, the first layer. The crests 120 are illustrated in a plan perspective in Figure 3 and Figure 5. At least one of the crests 120 extends through at least one filament of the second layer 200. In Figure 4, the crest 120 corresponds to peak 105A which extends through at least one filament 220.
Since the ridges extend through one or more filaments, the ridges may have a length greater than the maximum distance between the intersections of adjacent filaments 260 (the distance between intersections of adjacent filaments after the contraction of layer 200 and of the fold of layers 100 and 300). In particular, the length of the ridges 120 can begreater than the maximum dimension of the holes 250 in Figure 1 (greater than the length of the diagonal extending through the rectangular holes 250). The length of a ridge 120 is indicated by the letter L in figure 3. The length L is»S ~ zA the straight line distance between two ends of a ridge 120, the ends of ridge 120 are those points where a ridge 120 ends in a valley 107. In value of L it can be at least about 1.0 cm, more particularly at least about 1.5 cm for some of the crests 120. In one embodiment, at least some of the crests 120 have a length L of at least about 2.0 cm. The length L can be at least twice the distance between the intersections of adjacent filaments. For example, to determine the length of the ridges 120 relative to the distance between the intersections of adjacent filaments, the cleaning sheet 20 can be moistened and placed on a table with light or another suitable source of backup lighting. Said back-up light, in combination with the wetting of the cleaning sheet, can be used to make the intersections of filaments of the layer 200 visible through the layer 100, so that the lengths of the ridges 120 relative to the distance between intersections of filaments can be measured with a scale. The elongated crests provide gentle cleaning elements that can be deformed to improve the removal of material from the surface being cleaned. In contrast, if the filaments of the second layer were continuously bonded to the first and second layers, then any texture characteristics of the first and third layers would be confined to the area related to the holes 250 in the second layer 200.
At least some elongated ridges extend in a different direction from at least some of the other ridges. With respect to Figure 3, crests 120A, 120B and 120C extend in a different direction.
Consequently, the sheet is effective when picking up material, when the sheet is used to clean in different directions. Figures 3 and 6 also illustrate that at least some of the crests 120 may have branches extending in different directions. In Figure 3, a ridge 120 is illustrated with three branches 123A, 123B and 123C that extend in different directions. Similarly, Figure 6 shows a ridge 120 having at least three branches marked as 123A, 123B and 123C. The first layer 100 and the third layer 300 are securely attached to the second layer 200 at the intersections of filaments 260. Figure 9 illustrates the joining of fibers of both layers 100 and 300 to the second layer at an intersection of filaments 260 With respect to Figures 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 Figure 4, the peak 305A of the third layer does not directly include the peak 105A, but instead, is generally aligned with the valley 107A related to the 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 for making multi-layered cleaning sheets. A first non-woven layer, a second layer including a placement similar to a filament network, and a third non-woven layer are provided. The first layer is placed adjacent to an upper surface of the second layer, facing the second layer. The third layer is placed adjacent to a lower surface of the second layer facing the second layer. The first layer and the third layer then intermittently join separate and discrete portions of the second layer, so that the portions of the filaments extending between the intersections of filaments remain unjoined with the first layer, and so that the portions of the filaments extending between the intersections of filaments remain unattached with the third layer. The second layer contracts with respect to the first layer and the third layer to provide a macroscopically three-dimensional, folded-out surface of the first layer, as well as a macroscopically three-dimensional, folded-out surface of the third layer. The steps to join and contract may occur at the same time or be a consequence. The step to intermittently join the second layer with the first layer and the third layer may include the step to pressurize the first layer, the second layer and the third layer at a relatively low pressure for a relatively short period to prevent relatively continuous joining of the second layer with 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 applying pressure in the hand press at a temperature of about 165.5 ° C for about 13 seconds. The manual press has an adjustment to vary the gap, and therefore the pressure with which the press has. The adjustment can be varied at will to provide the desired texture in layers 100 and 300. Also, the invention comprises the packages containing the cleaning sheets, packages that are related to the information intended for the consumer, by means of words and / or drawings, that the use of the sheets will provide cleaning benefits that include the removal and / or removal of dirt (for example, dust, lint, etc.), and this information may include the assertion of superiority over other cleaning products. In a highly desirable variation, the package carries the information intended for the consumer that the use of the cleaning sheet offers the reduction of levels of dust and other type of matter transported through the air in the atmosphere. It is very important that the consumer is informed of the potential use of the sheets on unusual surfaces, including fabrics, PET, etc., to ensure the total benefits of the sheet. Accordingly, it is important to use packages related to information intended for the consumer, by means of words and / or drawings, on the use of the compositions that will provide the benefits, such as improved cleaning, reduction of particulate airborneness, etc. , as explained in the present. The information may include, for example, advertising in all common media, as well as phrases and icons in the package or on the sheet itself to inform the consumer. The above products that do not include the preferred structures herein may be employed 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 obtain the full value of improved performance in relation to conventional products or practices.lll) Cleaning implements In another aspect, the present invention relates to a cleaning implement that includes the cleaning sheets described above. In this regard, the cleaning implement includes: a) A handle; and b) A removable cleaning sheet having a first surface and a second surface, wherein the average peak to peak distance is at least about 1.0 mm and the surface topography index is 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 wood, vinyl, linoleum, floors without wax, ceramic, FORMAL®, porcelain and the like. The handle of the cleaning implement comprises any durable and elongated material that will offer a practical cleaning in terms of ergonomics. The length of the handle will be determined by the final use of the implement. Preferably, the handle will include at one end a support head to which the cleaning sheet can be removably attached. For ease of use, the support head can be pivotally connected to the handle using known joining assemblies. Any suitable means for attaching the cleaning sheet to the support head can be used, as long as the cleaning sheet remains held during the cleaning process. Examples of suitable fastening means include jaws, hooks and clips (e.g., VELCRO®), and the like. In a preferred embodiment, the support head will include means for holding the sheet by the top surface to keep the sheet mechanically attached to the head during severe cleaning procedures. However, the fastening means will easily detach from the sheet for convenient removal and disposal. The cleaning sheets useful in the cleaning implement of the present invention are in accordance with the above description.i t &i IV) Test methodsA) Average height differential The average height differential is determined using a light microscope (eg, Zeiss Axioploan, Zeiss Company, Germany) equipped with a Z-dimension measurement device (eg, Microcode II, sold by Boeckeler, Instruments). This procedure covers the location of a peak or valley region of the sheet, focusing the microscope and zeroing the Z-dimension measuring device. Then, the microscope moves to an adjacent valley or peak region, respectively, and returns to focus The display means of the instrument indicates the difference in height between this peak / valley or valley / peak pair. The measurement is repeated at least 10 times at random locations on the sheet, and the average height differential is the average of these measurements.
B) Peak to Peak Distance A single light microscope can be used to measure the peak-to-peak distance. The increase used should be sufficient to easily measure the distance between two adjacent peaks. This measurement is repeated at least 10 times, at random locations on the sheet, and the average peak-to-peak distance is the average of these measurements.r l? iffiHfrli-ir- C) CD extension to 500 q The CD extension is a measure of the percentage of prolongation that a test sample throws under a load of 500 g. The CD extension can be measured using a Sintech Renew Instron 7310 (including the Testworks software package) with a 100N load cell. By using this instrument a load is generated against% of a voltage curve. The test parameters are as follows: Sample width = 30 mm Manometer length = 100 mm Crosshead speed = 300 mm / minute From the generated curve, the software obtains the percentage of tension (percentage of extension) in a 500 g load This is reported as a CD extension to 500 g.
V) Representative examples Illustrative examples of the cleaning sheets of the present invention are shown below. Table 1 indicates the mentioned three-dimensionality.
EXAMPLE 1This example illustrates the combination of carded ribbons and a canvas (ie, a network of polypropylene filaments) to make a sheet of# ti * ij cleaning of the present invention. Two polyester fiber ribbons carded with a canvas in the middle are prepared. The combination of two carded ribbons and the canvas is then placed on top of a band forming openings (flat square N 50) and hydroentangled and dried. The hydroentangling process with water causes the fibers to become inter-tanned and they also become full with the canvas, at the same time causing the fibers to separate and provide two different base weight regions. During the drying process, the hydroentangled sheet becomes "cushioned" (ie, a greater three-dimensionality is achieved) as a result of the shrinkage of the polypropylene sheet relative to the non-woven polyester. As a preferred optional step, the surface of the non-woven sheet (by, for example, printing, spraying, etc.) is coated with 5% by weight of a 1: 1 mixture of mineral oil and paraffin wax. The hydroentangled nonwoven sheet is subjected to further heating, for example in a press at 180 ° C for 10 seconds to provide a higher degree of three-dimensionality. This sheet is designated as Example 1 in Table 1. (This heating can be carried out before or after adding the optional surface treatment, but preferably it is carried out before the application of the additive). This additional heating provides even a greatly improved three-dimensionality.
EXAMPLE 2A 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 the third layer 300 include a hydroentangled ribbon of polyester fibers having a basis weight of about 30 g per square meter. The second layer comprises the THERMANET® reinforcement mesh described above, which has a polypropylene / EVA resin, adhesive on both sides and a filament density of 3 strands every 2.54 cm for 2 strands every 2.54 cm before shrinkage of the second layer. The second layer 200 is placed between the first layer 100 and the third layer 300 in a BASIX B400 hand press. The three layers are joined by pressing the hand press at a temperature setting of about 165.5 ° C for about 13 seconds. The cleaning item has the measured values of average peak to peak distance, the average height differential and the surface topography index, as shown in table 1.
COMPARATIVE EXAMPLE AComparative Example A illustrates a non-woven sheet having a uniform basis weight that is essentially flat. The sheet is available on the market manufactured by Kao Coporation, Tokyo, Japan, as QUICKLE®.
TABLE 1