Patent Publication Number: US-2019168266-A1

Title: Scrubbing wipe and method for making same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/595,132, filed Dec. 6, 2017, the entire content of which is incorporated herein by reference. 
    
    
     FIELD 
     The present invention is directed to a scrubbing wipe that may be used in cleaning applications, and a method for making the scrubbing wipe. 
     BACKGROUND 
     Paper towels and other fiber-based wipes have been traditionally used as scrubbing substrates to clean a variety of surfaces. Such products are typically used in a single application and are then disposed of. 
     For a number of reasons, it is desirable to have a flexible material that can be used as a wipe for scrubbing surfaces, particular in cleaning applications, that is robust and can be reused multiple times in multiple applications. 
     SUMMARY 
     According to an aspect of the invention, there is provided a scrubbing wipe that includes a scrim that includes a plurality of filaments, and a formed film attached to the scrim. The formed film encompasses at least 50% of the circumferences of a portion of the plurality of filaments and includes a plurality of apertured extended cells extending away from the scrim. 
     According to an aspect of the invention, there is provided a method for manufacturing a scrubbing wipe. The method includes feeding a scrim that includes a plurality of filaments onto a forming structure that includes a plurality of apertures, extruding a polymer web onto the scrim as the scrim passes over the forming structure, and applying a vacuum through the forming structure to pull portions of the polymer web through openings in the scrim and into the apertures of the forming structure to form the scrubbing wipe that includes the scrim and a formed film attached to the scrim. The formed film encompasses at least 50% of the circumferences of a portion of the plurality of filaments and includes a plurality of apertured extended cells extending away from the scrim. 
     In an embodiment, the formed film encompasses at least 50% of the circumferences of substantially all of the plurality of filaments. 
     In an embodiment, outside surfaces of sidewalls of the apertured extended cells form scrubbing pockets with the filaments of the scrim. In an embodiment, at least some of the sidewalls of the apertured extended cells extend in a direction normal to a plane containing the scrim, and at least some of the sidewalls of the apertured extended cells extend at an angle relative to normal to the plane containing the scrim. 
     In an embodiment, the scrim has a basis weight in the range of 60-65 grams per square meter. 
     In an embodiment, the plurality of filaments of the scrim comprise polypropylene. 
     In an embodiment, each of the plurality of filaments has a diameter in the range of 430-560 micrometers. 
     In an embodiment, adjacent filaments are substantially parallel to each other and spaced apart by a distance in the range of 2.8-3.3 millimeters. 
     In an embodiment, the formed film has a basis weight in the range of 35-40 grams per square meter. 
     In an embodiment, the formed film comprises polyethylene. In an embodiment, the formed film comprises a blend of low density polyethylene and high density polyethylene. In an embodiment, the formed film further comprises a surfactant. 
     In an embodiment, the plurality of apertured extended cells are arranged in a pattern of 4-6 apertured extended cells per linear centimeter. 
     These and other aspects, features, and characteristics of the present invention, as well as the methods of manufacturing and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components of the following figures are illustrated to emphasize the general principles of the present disclosure and are not necessarily drawn to scale. Reference characters designating corresponding components are repeated as necessary throughout the figures for the sake of consistency and clarity. 
         FIG. 1A  schematically illustrates a top view of a scrubbing wipe in accordance with embodiments of the invention; 
         FIG. 1B  is a picture that illustrates a bottom view of the scrubbing wipe of  FIG. 1A ; 
         FIG. 2A  schematically illustrates a scrim that is part of the scrubbing wipe of  FIG. 1A ; 
         FIG. 2B  is a picture that illustrates the scrim that is part of the scrubbing wipe of  FIG. 1B ; 
         FIG. 3  schematically illustrates an embodiment of an apparatus used to manufacture the scrubbing wipe of  FIGS. 1A and 1B ; 
         FIG. 4  is a picture of a forming structure that is part of the apparatus of  FIG. 3 ; 
         FIG. 5  is a picture of the scrim of  FIG. 2B  on top of the forming structure of  FIG. 4 ; 
         FIG. 6A  schematically illustrates an enlarged view of a cross section of the scrubbing wipe of  FIG. 1A ; and 
         FIG. 6B  is a picture of a magnified cross-section of a portion of the scrubbing wipe of  FIG. 1B  showing a filament of the scrim attached to a formed film. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A and 1B  illustrate a scrubbing wipe  100  according to embodiments of the invention. As illustrated, the scrubbing wipe  100  includes a scrim  110  and a formed film  120  attached to the scrim  110 . 
     The scrim  110  is shown in further detail in  FIGS. 2A and 2B . As illustrated, the scrim  110  includes a plurality of filaments  112   a ,  112   b  that are arranged in a mesh-like or net-like pattern, with the filaments  112   a  being substantially parallel to and spaced from each other, and the filaments  112   b  being substantially parallel to and spaced from each other, as well as oriented at an angle to the filaments  112   a . The two sets of filaments  112   a  and  112   b  cross and are connected at intersections  114  by known methods. Each of the filaments  112   a ,  112   b  may be made from the same material, such as polypropylene, for example. In an embodiment, the filaments  112   a  and  112   b  may be made from different materials, such as polypropylene and polyethylene, respectively, for example. In an embodiment, one or more filament  112   a ,  112   b  made be made from more than one material, such as having a core made from one material and a sheath made from another material. Each of the filaments  112   a ,  112   b  may have a diameter in the range of 250-760 micrometers (10-30 mils), or in the range of 380-635 micrometers (15-25 mils), or in the range of 430-560 micrometers (17-22 mils). In embodiments in which the diameters of the filaments are smaller, the scrim may be considered to be netting. In an embodiment, the filaments  112   a  may have a different average diameter than the filaments  112   b . The spacing between adjacent filaments  112   a  and  112   b  may be in the range of 2.0-4.0 millimeters (78-158 mils), or in the range of 2.5-3.5 millimeters (98-138 mils), or in the range of 2.8-3.3 millimeters (115-125 mils), and the filaments  112   a  and  112   b  that intersect may be oriented substantially orthogonally to each other ±15°. In an embodiment, the spacing between the filaments  112   a  may be different than the spacing between the filaments  112   b . In an embodiment, the scrim  110  may have a basis weight in the range of 40-100 grams per square meter (gsm), or in the range of 50-70 grams per square meter (gsm), or in the range of 55-65 grams per square meter (gsm), or in the range of 60-65 grams per square meter (gsm). In an embodiment, more than one scrim may be used in the scrubbing wipe. 
     As noted above, the illustrated embodiment is intended to depict a condition where the intersecting filaments  112   a  and  112   b  are oriented substantially orthogonally to each other ±15°. This condition, however, should not be understood to limit the scope of the present invention. Other angular relationships between the intersecting filaments  112   a  and  112   b  are understood to be suitable alternatives, as should be apparent to those skilled in the art. 
     Returning to  FIGS. 1A and 1B , the formed film  120  is attached to the filaments  112   a ,  112   b  of the scrim  110 , as described in further detail below. The formed film  120  includes a plurality of apertured extended cells  122  that extend away from the scrim  110 . Each of the apertured extended cells  122  includes a continuous sidewall  124  surrounding an aperture  126  that extends through the formed film  120 . Each sidewall  124  starts at a land  128  of the formed film  120  and has a thickness that decreases as the sidewall  124  extends away from the land  128 , and scrim  110 , to a distal end. 
     It is contemplated that not all of the extended cells may be apertured extended cells  122  but that some of the extended cells will not have an aperture  126  that extends therethrough. The extended cells without apertures  126  will have solid distal ends and, therefore, will not permit fluid to flow therethrough. While not intending to limit the present invention, it is contemplated that the formed film may include a greater number of apertured extended cells  122  than extended cells without apertures  126 . To this end, a ratio of apertured extended cells  122  to extended cells without apertures  126  is contemplated to be 50% or more. Other contemplated ratios include 60%, 70%, 80%, 90%, 95%, and 100%. While a predominance of apertured extended cells  122  are contemplated for many embodiments of the present invention, it is also contemplated that some other embodiments may incorporate a predominance of extended cells without apertures  126 . As noted, the precise ratio is not intended to limit the scope of the present invention. 
     In addition, although  FIG. 1A  schematically illustrates that the apertured extended cells  122  have the same size, embodiments of the invention include the apertured extended cells  122  having different sizes, as shown in  FIG. 1B  and described in further detail below. In an embodiment, the formed film  120  may have a basis weight in the range of 20-80 grams per square meter (gsm), or in the range of 25-50 grams per square meter (gsm), or in the range of 30-45 grams per square meter (gsm), or in the range of 35-40 grams per square meter (gsm). Additional details of the formed film and scrubbing wipe in accordance with embodiments of the invention are described below. 
       FIG. 3  illustrates an apparatus  300  that may be used to manufacture scrubbing wipes in accordance with embodiments of the invention, including the scrubbing wipe  100  described above. As illustrated, a scrim  302 , such as the scrim  110  described above, may be unwound from a scrim roll  304  and fed to a forming structure  306 , such as a rotating forming screen. An extrusion die  310  is located at the end of at least one extruder (not shown) and is configured to form a polymer web  312 . The polymer web  312  may be a single layer or a multi-layer polymer web. The material used to form the polymer web  312  may comprise polyethylene (PE) and/or polypropylene (PP). In an embodiment, the material used to form the polymer web  312  may be a blend of one or more polymers selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and polypropylene (PP). In an embodiment, the polymer web  312  may be a blend of, for example, low density polyethylene (LDPE) and high density polyethylene (HDPE). In an embodiment, the polymer web  312  may also include a surfactant and/or other additives, such as colorants, as desired. 
     In the embodiment illustrated in  FIG. 3 , the polymer web  312  exits the extrusion die  310  and is deposited onto the scrim  302  as the scrim  302  is passing over the forming structure  306  as the forming structure  306  rotates around a fixed vacuum slot  308  in which a vacuum is pulled. The forming structure  306  includes a plurality of apertures  400  arranged in one or more patterns, as illustrated in  FIG. 4 . In an embodiment, the plurality of apertures  400  are sized and arranged so that there are 10-15 apertures per linear inch (4-6 apertures per linear centimeter), or a 10-15 “mesh pattern” as is understood by persons of ordinary skill in the art. The apertures  400  may have different shapes and sizes than the shape and size illustrated in  FIG. 4 . The illustrated embodiment is not intended to be limiting in any way. 
       FIG. 5  illustrates the scrim  302  on top of the forming structure  306  before the polymer web  312  is extruded on top of the scrim  302  and the forming structure  306 . As illustrated, the apertures  400  in the forming structure  306  are smaller and of a different shape than openings  500  defined by filaments  510  of the scrim  302 . An effect of the differences between the sizes of apertures  400  and openings  500  is described in further detail below. 
     When the polymer web  312  on the scrim  302  and the forming structure  306  passes over the vacuum slot  308 , the portions of the polymer web  312  that are directly over the apertures  400  in the forming structure  306  are pulled into the apertures  400  to form extended cells (with or without apertures) that extend away from the scrim  302 . The remaining portions of the polymer web  312  coat the exposed surfaces of the scrim  302  that are not in contact with the forming structure  306  and also contact the forming structure  306  in between the apertures  400 . Because some of the apertures  400  in the forming structure  306  may be partially blocked by filaments of the scrim  302 , some of the extended cells may be partially formed (and not actually be apertured) or have a different shape and/or size than the apertured extended cells that are formed without such obstructions, as described in further detail below. 
     The pulling of the polymer web  312  around the filaments  510  of the scrim  302  and towards the apertures  400  in the forming structure  306  also causes the polymer web  312  to attach to and encompass at least 50% of the circumferences of a portion of (i.e., some of) the plurality of filaments  510  of the scrim  302 , which secures the scrim  302  to the polymer web  312 , thereby resulting in the formed film. In the context of the present invention, “a portion of the plurality of filaments” is intended to refer to the manufactured condition where some of the filaments  510  of the scrim  302  are wrapped by the polymer web  312  so that at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . More specifically, the term “a portion of the plurality of filaments” is intended to mean that between 50% to 100% of the filaments  510  of the scrim  302  are coated by the polymer web  312  so that at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . As should be apparent, it is contemplated that some of the filaments  510  may not be encompassed by the polymer web  312  to a state where at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . 
     Separately, it is contemplated that, during manufacture, the polymer web  312  may attach to and encompass at least 50% of substantially all of (i.e., most or all of) the plurality of filaments  510  of the scrim  302 . Here, “substantially all of the plurality of filaments” is intended to refer to the manufactured condition where most (or all) of the filaments  510  of the scrim  302  are wrapped by the polymer web  312  so that at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . More specifically, the term “substantially all of the plurality of filaments” is intended to mean that between 90% to 100% of the filaments  510  of the scrim  302  are coated by the polymer web  312  so that at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . Even here, it is contemplated that a few of the filaments  510  may not be encompassed by the polymer web  312  to a state where at least 50% of the circumferences of those filaments  510  are encompassed by the polymer web  312 . 
     Returning to  FIG. 3 , the forming structure  306  also cools the polymer web  312  as it is transformed into a formed film so that the resulting scrubbing wipe  320 , such as the scrubbing wipe described above and below, may be pulled off of the forming structure  306  by a roller  322 , conveyed to a winder  324  via additional rollers  326 ,  328 , and wound into a roll  330  by the winder  324 . The illustrated embodiment is not intended to be limiting in any way. For example, in another embodiment, instead of extruding the polymer web  312  directly onto the scrim  302  and the forming structure  306 , a polymer web that had been previously extruded onto a chilled roll and quenched into a solid polymer web may be reheated and conveyed to scrim  302  and the forming structure  306 . 
       FIG. 6A  is a schematic cross-section of a portion of the scrubbing wipe  320  formed on the apparatus  300  of  FIG. 3 . As illustrated, the scrubbing wipe  320  includes a scrim that includes a plurality of filaments  612   a ,  612   b ,  612   c ,  612   d , and a formed film  620 . The filaments  612   a ,  612   b ,  612   c ,  612   d  are substantially parallel to and spaced from each other. The formed film  620  includes a land  622 , and a plurality of apertured extended cells  624  extending from the land  622  and away from the filaments  612   a ,  612   b ,  612   c ,  612   d  of the scrim.  FIG. 6B  illustrates a single filament  612  with the formed film  620 . As illustrated in  FIGS. 6A and 6B , the formed film  620  is attached to the scrim and encompasses at least 50% of the circumferences of the illustrated filaments  612 ,  612   a ,  612   b ,  612   c ,  612   d.    
     The location of the filaments  612  of the scrim relative to the apertures  400  of the forming structure  306  may influence the shape of each apertured extended cell  624 . For example, if a filament  612  passes over an aperture  400  near an edge of the aperture  400  thereby partially blocking the aperture  400 , the polymer web will coat the filament  612  and be pulled into the aperture  400 , which will bend the polymer web around the filament  612  so that the extended cell  624  will have a sidewall that is angled relative to normal (i.e. perpendicular) to the scrim. This bending of the polymer will cause part of the sidewall to be located directly underneath the filament, as illustrated in  FIG. 6A  at the leftmost and rightmost filaments  612   a  and  612   d . Such bending of the sidewall of the extended cell  624  creates an angled scrubbing pocket  626  between the sidewall of the extended cell  624  and the filament  612 . For an aperture  400  in the forming structure  306  that is not blocked by one or more filaments, an apertured extended cell  625  will more fully form and extend substantially normal or perpendicular to the scrim, as illustrated in  FIG. 6A  in between filaments  612   b  and  612   c , and create “neutral” (i.e. not angled) scrubbing pockets  628 . The more fully formed apertured extended cells  625  will have larger apertures and longer sidewalls, as compared to the extended cells  624  that are at an angle relative to normal to the scrim. This random, but frequent, combination of “neutral” and angled scrubbing pockets oriented in different directions, as well as different lengths of the sidewalls of the extended cells, may provide the scrubbing wipe  320  with good scrubbing action regardless of the direction of motion of the scrubbing wipe in use. And, as discussed above, some of the extended cells may not be apertured. 
     EXAMPLE 
     The apparatus  300  illustrated in  FIG. 3  was used to extrude a polymer web  312  comprising low density polyethylene, high density polyethylene, a surfactant, and a colorant onto the scrim  302  and forming structure  306  (illustrated in greater detail in  FIG. 5 ) after the scrim  302  was unrolled from the scrim roll  304  and fed to the forming structure  306 . The polymer web  312  had a basis weight of about 36 grams per square meter (gsm). The scrim  302  had a basis weight of about 63 grams per square meter (gsm), and the polypropylene filaments had an average diameter of about 20 mils (about 508 micrometers or microns). Adjacent filaments were spaced apart by about 120 mils (about 3 millimeters) in one bias direction and by about 115 mils (about 2.9 millimeters) in the other bias direction. The forming structure  306  had apertures  400  in the shape of an elongated hexagon with two opposing sides shorter than the remaining sides, as illustrated in  FIG. 4 . The apertures  400  were arranged in a 13 mesh pattern, i.e. 13 apertures per linear inch (about 5 apertures per linear centimeter). 
     A suitable vacuum was generated in the vacuum slot  308  to pull the polymer web  312  against the forming structure  306  with the scrim  302  positioned therebetween, as well as pull portions of the polymer web  312  into the apertures  400  of the forming structure  306 . The polymer web  312  transformed into the formed film portion of the scrubbing wipe  320  (shown as the scrubbing wipe  100  in  FIG. 1B ) as the polymer web  312  cooled on the forming structure  306 . The scrubbing wipe  320  was pulled off of the forming structure  306  with a roller  322  and wound into a roll  330 . 
     Scrubbing wipes in accordance with embodiments of the invention each has a first side having a first texture substantially defined by the scrim coated by the formed film, and a second side having a second texture different from the first texture and substantially defined by the apertured extended cells of the formed film and scrubbing pockets created by the formed film and filaments of the scrim, as described above. The first texture may have a roughness that is greater than the roughness of the second texture, which may provide the scrubbing wipe with greater versatility than a scrubbing wipe with both sides having the same texture and roughness. In addition to the good scrubbing action provided by both sides of the scrubbing wipes, scrubbing wipes according to embodiments of the invention allow fluids, such as water and/or soaps and other cleaners, to flow through the scrubbing wipes, which may enhance the scrubbing action even further. In an embodiment, the scrubbing wipe may be used in conjunction with an absorbent material configured to deliver fluids to the scrubbing wipe and/or absorb excess fluids. Scrubbing wipes in accordance with embodiments of the invention are compression resistant and provide a void volume when used with other substrates and materials. 
     Although embodiments of the invention described above are directed to scrubbing wipes, it is contemplated that the same or similar structures may be used in other applications. For example, embodiments of the invention may be used for ground covering, breathable wrap, or any other application in which rigidity and fluid transport through the material are desired. 
     The embodiments described herein represent a number of possible implementations and examples and are not intended to necessarily limit the present disclosure to any specific embodiments. Instead, various modifications can be made to these embodiments as would be understood by one of ordinary skill in the art. Any such modifications are intended to be included within the spirit and scope of the present disclosure and protected by the following claims.