Wiping product with topographic pattern

Abstract

A nonwoven material is disclosed that includes a surface topography that is well suited for cleaning contaminants, particularly oils and / or greases.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 421,596, filed on November 2, 2022, which is hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION

[0003] Household and industrial wipes are often used to pick up and absorb polar and non-polar liquids. The wipes should be constructed to have sufficient absorbency to hold the liquid within the wipe structure. In addition, the wipes should also have good physical strength and abrasion resistance to withstand the tearing, stretching, and abrasive forces that are often applied during use.

[0004] Traditional wiping products are made from woven and knitted fabrics. Such wipes have been used in all different types of industries, such as for industrial applications, food service applications, health and medical applications, and for general consumer use.

[0005] In the past, non-woven wipes have also been made from pulp fibers alone or in combination with synthetic fibers. For example, in the past, spunbonded webs made from continuous filaments have been hydroentangled with pulp fibers to produce elastic wiping products. In many cases, these webs are used for single-use applications and then discarded. While these wipes have good strength and water absorbency levels, they generally do not have the same cleaning characteristics as woven and knitted fabrics, especially when wiping away oil and grease.

[0006] In view of the above, there is a current need for a disposable non-woven wipe having improved oil and grease cleaning performance. There is also a need for a disposable non-woven wipe that is particularly well-suited for cleaning oil and grease spills at a relatively low basis weight, especially compared to woven and knitted cleaning cloths. SUMMARY OF THE INVENTION

[0007] Generally speaking, the present disclosure relates to non-woven webs or substrates having excellent oil and grease cleaning performance. The non-woven webs are particularly suitable for use as industrial wipes. While the wipes are very suitable for picking up oil and grease, they can also be used for a variety of other applications. Specifically, the wipes have a combination of excellent absorbency and good strength characteristics. According to the present disclosure, the non-woven webs of the present disclosure have a particular morphology that maximizes the removal of grease as well as the absorption of oil.

[0008] In one embodiment, for example, the present disclosure relates to a wiping product that includes a nonwoven web having a first surface and an opposite second surface. The nonwoven web contains cellulose fibers, synthetic polymer fibers, or a mixture of cellulose fibers and synthetic polymer fibers. In one aspect, the nonwoven web has a basis weight of less than about 110 gsm. A topographical pattern is located on the first surface of the nonwoven web. At least a portion of the topographical pattern includes raised pattern elements extending from a base surface. When tested at 0.3 psi, the raised pattern of the elements produces a unit surface area pattern element perimeter of greater than about 0.08 / mm and a unit surface area pattern forming volume of greater than about 1.1 mm.

[0009] For example, when tested at 0.3 psi, the raised pattern elements can produce a unit surface area pattern element perimeter of greater than about 0.09 / mm, such as greater than about 0.1 / mm, such as greater than about 0.11 / mm, and even greater than about 0.12 / mm. When tested at 0.3 psi, the raised pattern elements can have a unit surface area pattern forming volume of greater than about 1.3 mm, such as greater than about 1.4 mm, such as greater than about 1.5 mm, such as greater than about 1.6 mm.

[0010] When tested at 0.3 psi, the nonwoven web can have a void volume of greater than about 75%, such as greater than about 78%, such as greater than about 80%, such as greater than about 82%. When tested at a pressure of 0.05 psi, the nonwoven web can have a density of about 0.1 g / cm 3 to about 0.18 g / cm 3 , such as about 0.12 g / cm 3 to about 0.14 g / cm 3 .

[0011] In one aspect, the raised pattern elements of the pattern include discrete shapes that are not interconnected. The basis weight of the nonwoven web where the raised pattern elements are located can be greater than the basis weight of the nonwoven web in the area where there are no raised pattern elements (e.g., the basis weight of the base surface). For example, the basis weight of the nonwoven web within the raised pattern elements can be greater than about 10% of the basis weight of the nonwoven web where there are no raised pattern elements, such as greater than about 20%, such as greater than about 30%, such as greater than about 40%. In one aspect, the raised pattern elements include raised circular elements. The raised pattern elements can have a perimeter of from about 0.5 mm to about 20 mm, such as from about 0.75 mm to about 10 mm, such as from about 1.5 mm to about 5 mm. In one embodiment, the topographical pattern of the nonwoven web can additionally include a contaminant retention area. The raised pattern elements can, for example, form a raised pattern area contiguous to the contaminant retention area. The contaminant retention area can be substantially planar and not have raised pattern elements. In one aspect, the contaminant retention area can include discrete areas that are not interconnected.

[0012] The raised pattern elements can have a height (measured from the bottom surface) greater than about 0.1 mm, such as greater than about 0.2 mm, such as greater than about 0.3 mm, such as greater than about 0.4 mm, such as greater than about 0.5 mm, such as greater than about 0.6 mm, and typically less than about 1.2 mm, such as less than about 1 mm, such as less than about 0.8 mm. Similar to density, the height of the raised pattern elements can be measured at a pressure of 0.05 psi. The raised pattern elements can be spaced apart by any suitable amount. In one embodiment, the raised pattern elements are spaced apart by an average distance of from about 0.5 mm to about 1.5 mm. When tested at a pressure of 0.05 psi, the nonwoven web can have a thickness measured from the top of the raised pattern elements greater than about 0.4 mm, such as greater than about 0.8 mm, such as greater than about 1.2 mm, such as greater than about 1.5 mm, such as greater than about 2 mm, such as greater than about 2.5 mm, and less than about 5 mm, such as less than about 3 mm, such as less than about 1 mm.

[0013] The nonwoven web can have a basis weight of from about 35 gsm to about 100 gsm, such as from about 50 gsm to about 90 gsm, such as from about 50 gsm to about 70 gsm. In one aspect, the nonwoven web contains from about 5 wt% to about 65 wt%, such as from about 15 wt% to about 45 wt% of synthetic polymer fibers, and from about 35 wt% to about 95 wt%, such as from about 55 wt% to about 85 wt% of cellulose fibers. The nonwoven web can also contain binder fibers and / or wet strength agents. The nonwoven web can include a foam-formed web and can contain a balance of surfactant. The raised pattern elements can occupy from about 15% to about 80% of the surface area of the first surface, such as from about 20% to about 60% of the surface area of the first surface. In one aspect, the topographical pattern includes a first raised pattern element and a second raised pattern element. The first raised pattern element can have a perimeter that is less than the perimeter of the second raised pattern element.

[0014] In one aspect, the synthetic polymer fibers include polyester fibers. The polyester fibers can have a fiber size of from about 0.5 denier to about 3 denier. In one aspect, the synthetic polymer fibers can include a first polyester fiber and a second polyester fiber. The first polyester fiber can have a fiber size of less than about 1.5 denier. The first polyester fiber can have a size that is less than the second polyester fiber.

[0015] Other features and aspects of the present disclosure are discussed in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 is a perspective view of one embodiment of a nonwoven material manufactured in accordance with the present disclosure;

[0018] Figure 2 is a perspective view of another embodiment of a nonwoven material manufactured in accordance with the present disclosure;

[0019] Figure 3 is a cross-sectional view of one embodiment of a nonwoven material manufactured in accordance with the present disclosure, showing pressure being applied to the nonwoven material against an adjacent surface to simulate product use;

[0020] Figure 4 is a schematic view of one embodiment of a method for forming a nonwoven material in accordance with the present disclosure; and

[0021] Figure 5 is Figure 4 a partial enlarged schematic view of the schematic view shown.

[0022] The repeated use of reference numerals in this specification and the drawings is intended to represent the same or similar features or elements of the present invention.

[0023] Definitions

[0024] As used herein, the term "longitudinal direction" refers to the direction of travel of the forming surface on which the fibers are deposited during the formation of the nonwoven web.

[0025] As used herein, the term "transverse direction" refers to a direction perpendicular to the longitudinal direction as defined above.

[0026] As used herein, the term "cellulose fiber" refers to fibers from natural sources such as woody and non-woody plants. Woody plants include, for example, deciduous and coniferous trees. Non-woody plants include, for example, cotton, flax, esparto, milkweed, straw, jute, hemp, and bagasse. "Pulp fiber" refers to delignified cellulose fibers and may include hardwood fibers, softwood fibers, and mixtures thereof.

[0027] As used herein, the term "average fiber length" refers to the average length of fibers, fiber bundles, and / or fibrous materials determined by measurement using microscopic techniques. A sample of at least 20 randomly selected fibers is separated from a liquid suspension of the fibers. The fibers are placed on a microscope slide that has been prepared to suspend the fibers in water. A coloring dye is added to the suspended fibers to color the cellulose-containing fibers so that they can be distinguished or separated from synthetic fibers. The slide is placed under a Fisher Stereomaster II microscope - S19642 / S19643 series. Twenty fibers in the sample are measured at 20X linear magnification using a 0 - 20 mil scale, and the average length, minimum and maximum lengths, and deviation or coefficient of variation are calculated. In some cases, the average fiber length will be calculated as the weighted average length of the fibers (e.g., fibers, fiber bundles, fibrous materials), which is determined by equipment such as the Kajaani Fiber Analyzer model FS - 200 obtained from Kajaani Oy Electronics, Kajaani, Finland. According to standard test procedures, the sample is treated with an impregnating solution to ensure the absence of fiber bundles or debris. Each sample is decomposed in hot water and diluted to a suspension of approximately 0.001%. When tested using standard Kajaani fiber analysis test procedures, test samples of approximately 50 ml to 100 ml each are drawn from the diluted suspension. The weighted average fiber length can be an arithmetic mean, a length-weighted mean, or a weight-weighted mean, and can be represented by the following equation:

[0028]

[0029] wherein

[0030] k = maximum fiber length

[0031] x i = fiber length

[0032] n i = number of fibers of length xi

[0033] n = total number of fibers measured.

[0034] One characteristic of the average fiber length data measured by the Kajaani fiber analyzer is that it does not distinguish between different types of fibers. Thus, the average length represents the average based on the lengths of all different types (if any) of fibers in the sample.

[0035] As used herein, the term "short fiber" means a discontinuous fiber made from synthetic polymers such as polypropylene, polyester, post-consumer recycled (PCR) fibers, polyester, nylon, etc., or cellulose fibers such as cotton fibers, bast fibers, regenerated cellulose fibers (e.g., viscose fibers, rayon, etc.). Short fibers can be cut fibers, etc. Short fibers can have a cross-section that is round, bicomponent, multicomponent, shaped, hollow, etc.

[0036] As used herein, the term "nonwoven web or material" refers to a web having a structure of individual fibers, yarns, or mixtures thereof that are in an interlayered but not in an identifiable manner (such as in a knitted or woven fabric). Nonwoven materials include, for example, carded webs, wet-laid webs, air-laid webs, foam-formed webs, etc.

[0037] As used herein, the term "paper thickness" is the representative thickness of a single sheet determined in accordance with TAPPI test method T402 using an EMVECO 200-A Microgage automated micrometer (EMVECO, Inc., Newberg, Oreg.). (For a tissue product having two or more plies, the paper thickness is the thickness of a single sheet tissue product including all plies.) The micrometer has an anvil diameter of 2.22 inches (56.4 mm) and an anvil pressure of 132 grams per square inch (6.45 grams per square centimeter) (2.0 kPa).

[0038] As used herein, the term "paper bulk" refers to the quotient of the paper thickness (generally in μm) divided by the dry weight on an anhydrous basis (generally in gsm).

[0039] As used herein, "void volume" is the amount of space within a nonwoven material that is not occupied by solid materials such as fibers. In one aspect, the void volume per unit surface area can be determined. The void volume can be measured at an applied pressure, such as at a pressure of 0.05 psi or 0.3 psi.

[0040] As used herein, the "height of the raised pattern element" is the height by which the pattern element protrudes above the base surface of the nonwoven material. The height of the raised pattern element is measured at 0.05 psi.

[0041] As used herein, the "void surface area" is the area of the base surface of the nonwoven material that does not have raised pattern elements.

[0042] As used herein, the "pattern formation volume" is the void volume between the base surface of the nonwoven web and the plane contacting the top surface of the raised pattern element when a pressure of 0.3 psi is applied. The pattern formation volume can be calculated per unit surface area of the nonwoven material.

[0043] As used herein, the "perimeter of the pattern element" is the distance around the edge of the raised pattern element and is determined when a pressure of 0.3 psi is applied. The perimeter of the pattern element can be based on per unit surface area of the nonwoven material.

[0044] The methods for determining the "pattern formation volume" and the "perimeter of the pattern element" are carried out using the following methods.

[0045] The methods for determining the contact perimeter, the pattern formation void volume per unit area, and the void volume include a first step of obtaining digital X-ray micro-CT images of the sample. These images are acquired using a SkyScan 1272 Micro-CT system available from Bruker microCT (2550 Kontich, Belgium). A circular 3 / 4-inch cut diameter sample is flatly attached to a mounting device provided by Bruker with the SkyScan 1272 system so that it does not move under its own weight during the scanning process. In addition to the sample itself, 20 g, 50 g, and 100 g weights are placed on top of the sample prior to the micro-CT scan. The following SkyScan 1272 conditions are used during the scan:

[0046] - Source voltage (kV) = 30

[0047] - Source current (uA) = 200

[0048] - Image pixel size (μ) = 5.0

[0049] - Image format = TIFF

[0050] - Rotation step (degrees) = 0.1

[0051] - Use 360-degree rotation = No

[0052] - Frame averaging = On (6)

[0053] - Random movement = On (1)

[0054] - Flat-field correction = On

[0055] - Filter = No filter

[0056] After the sample scan is completed, the resulting set of X-ray images is then reconstructed using the NRecon program provided with the SkyScan 1272 micro-CT system. Although the reconstruction parameters may depend to some extent on the sample and should be known to those skilled in the art, the following parameters should provide basic guidance for the analyst:

[0057] - Image file type = JPG

[0058] - Pixel size (μm) = 5.0

[0059] - Smoothing = 1 (Gaussian)

[0060] - Ring artifact correction = 7

[0061] - Beam hardening correction (%) = 10

[0062] After the reconstruction is completed, the resulting image data set can now be used for percentage internal porosity and object surface area / volume measurement analysis using the Bruker SkyScan software package called CTAn. After downloading the entire reconstructed image data set into CTAn, an analyst familiar with the field of micro-CT technology must perform pre-analysis processing such as gray-scale thresholding and despeckling. Finally, a shrink-wrap region of interest (ROI) is performed so that the material fibers are completely enclosed within the ROI. Standard void volume and porosity parameters can now be used to select and perform 3D analysis. After completion, the 3D results will be provided in a.txt file located in the same folder as the reconstructed image slices. Finally, use the Save Bitmaps command of the CTAn software to save the ROI image slices for subsequent image analysis.

[0063] In addition to internal porosity and surface / volume analysis, image analysis can also be used to analyze the ROI image slices to obtain the pattern-forming void volume of each analysis region area from the top material surface to the underlying material region that is completely occupied by the fiber material structure. The top material perimeter of the pattern elements of each analysis region area is also measured based on the ROI image slices.

[0064] The image analysis software platform used for pattern-forming void volume and pattern element perimeter measurement can be QWIN Pro (version 3.5.1) or LAS (version 14.3) obtained from Leica Microsystems (with offices in Heerbrugg, Switzerland).

[0065] Thus, the method for determining the pattern formation void volume and the perimeter measurement of pattern elements for a given sample includes the step of measuring ROI image slices from a micro-CT image set. Specifically, an image analysis algorithm is used to read and process the images and perform measurements using the Quantimet User Interactive Programming System (QUIPS) language. The image analysis algorithm is reproduced below.

[0066] Name = ROI Shrunken Wrapped Area, % Area, and Perimeter (Micro-CT)

[0067] Purpose = Measure swab % area, area, perimeter, and void volume using shrunken wrapped ROI

[0068] Condition = Images acquired for SkyScan 1272 and CTAn processing

[0069] AUTHOR = D.G. Biggs

[0070] Date = August 26, 2022

[0071] Enter sample ID and open data file

[0072] Configure(Image Store 1392x 1040, Grey Images 348, Binaries 24)

[0073] PauseText("Enter EXCEL data file name now.")

[0074] Input(FILENAME$)

[0075] OPENFILE$ = "C:\Data\03126 - Baker\" + FILENAME$ + ".xls"

[0076] Open File(OPENFILE$, channel#CHAN)

[0077] Calibrate image

[0078] -Calvalue = 0.05mm / px

[0079] Calculated value = 0.05

[0080] Calibrate (local)

[0081] Enter result header

[0082] File Results Header(channel#1)

[0083] File line (channel#1)

[0084] REPLICATE = 0

[0085] SAMPLE = 0

[0086] ACQOUTPUT = 0

[0087] SET-UP

[0088] PauseText("Enter complete image pre-fix name")

[0089] Input(TITLE$)

[0090] File (TITLE$, channel#1)

[0091] File line (channel#1)

[0092] File("ROI image No.",channel#1)

[0093] File("%Area",channel#1)

[0094] File("Area(sq.mm)",channel#1)

[0095] File("Perimeter(mm)",channel#1)

[0096] File("Void Area(sq.mm)",channel#1)

[0097] File line (channel#1)

[0098] Image frame(x 0,y 0,Width 3964,Height 3964)

[0099] Measure frame(x 846,y 740,Width 2475,Height 2604)

[0100] -- Note: Set the following lines to read the ROI image number before executing the algorithm.

[0101] For(SAMPLE = 1437 to 1229,step -1)

[0102] ACQUIRE IMAGE

[0103] ACQOUTPUT = 0

[0104] -- Note: The following lines must be set to read from the directory where the image is located.

[0105] ACQFILE$ = "C:\Images\03126 - Baker\ROI Images\WAVE No load\" + TITLE$ + "" + STR$(SAMPLE) + ".jpg"

[0106] Read image (from file ACQFILE$ into ACQOUTPUT)

[0107] Colour Transform (Mono Mode)

[0108] Detection and Image Processing

[0109] PauseText("Select optimal gray detection")

[0110] Detect (whiter than 64, from Image0 into Binary0)

[0111] Detect (blacker than 194, from Image0 into Binary4)

[0112] Binary Amend (Open from Binary0 to Binary1, cycles 6, operator Disc, edgeerode on)

[0113] Binary Amend (Close from Binary1 to Binary2, cycles 5, operator Disc, edge erode on)

[0114] Binary Recognition (Fill holes from Binary2 to Binary3)

[0115] Binary Logical (C = A OR B: C Binary5, A Binary3, inverted, B Binary4)

[0116] Field Measurement

[0117] Measure frame(x 846,y 740,Width 2475,Height 2604)

[0118] MFLDIMAGE = 3

[0119] Measure field(plane MFLDIMAGE, into FLDRESULTS(3), statistics into FLDSTATS(7,3))

[0120] Selected parameters: Area, Perimeter, Area %

[0121] AREA = FLDRESULTS(1)

[0122] PERIM = FLDRESULTS(2)

[0123] PERCAREA = FLDRESULTS(3)

[0124] MFLDIMAGE = 5

[0125] Measure field(plane MFLDIMAGE, into FLDRESULTS(1), statistics into FLDSTATS(7,1))

[0126] Selected parameter: Area

[0127] VOIDAREA = FLDRESULTS(1)

[0128] Output

[0129] File(SAMPLE, channel#1, 0 digits after '.')

[0130] File(PERCAREA, channel#1, 1 digit after '.')

[0131] File(AREA, channel#1, 1 digit after '.')

[0132] File(PERIM, channel#1, 1 digit after '.')

[0133] File(VOIDAREA, channel#1, 1 digit after '.')

[0134] File line(channel#1)

[0135] Next(SAMPLE)

[0136] File line (Channel #1)

[0137] File line (Channel #1)

[0138] Close file (Channel #1)

[0139] End

[0140] The algorithm is executed using the Leica QWIN or LAS platform. Once the algorithm analyzes the specified image, the raw data results can be found in an EXCEL file located in the specified computer hard drive folder shown in the "Open file" line above. The data column headings will include the ROI image number, % area of the ROI, area and perimeter, and the void area of the non-ROI region. The void volume measurement is calculated by summing all the void area measurements from the lowest ROI % area measurement up to the highest percentage area measurement. This value is multiplied by the pixel calibration factor (i.e., 0.05 mm), and then divided by the area of the measurement frame (i.e., 16,122 square millimeters). The perimeter per unit area is calculated by taking the average of the first three perimeters of the pattern element values and then dividing this value by the area of the measurement frame, as shown above.

[0141] The above measurements can be made while applying pressure. The pressure can be, for example, 0 psi, 0.1 psi, 0.2 psi, 0.3 psi, 0.4 psi, 0.5 psi, 0.6 psi, 0.7 psi, or 0.8 psi. In one aspect, for example, the measurements are made while applying a pressure of 0.3 psi. Detailed Description

[0142] Those of ordinary skill in the art will understand that this discussion is only a description of exemplary embodiments and is not intended to limit the broader aspects of the disclosure.

[0143] Generally, the present disclosure relates to nonwoven materials designed to have a particular topography, which has been found to have many advantages and beneficial effects. The topography can include a pattern of raised elements extending from the base surface of the nonwoven material. By controlling various different properties of the raised elements and the nonwoven material, nonwoven materials with enhanced cleaning properties can be produced. For example, in one aspect, the nonwoven material can be used as a wipe with improved oil and / or grease cleaning effects, such as an industrial wipe.

[0144] More specifically, the nonwoven materials of the present disclosure include a pattern of raised elements that can have, for example, a cylinder-like shape extending from the base surface of the nonwoven material. The raised elements are spaced apart in the pattern to improve the removal of grease and / or oil from the surface. For example, the raised pattern elements have a certain height that forms a void volume between the base surface of the nonwoven material and the top of the raised elements. This void volume is well-suited for capturing contaminants such as grease and oil. Additionally, the raised elements create a pattern element perimeter for contacting contaminants such as grease and / or oil and collecting these contaminants in the void surface area, where the perimeter of the pattern element is formed by the edges of the raised elements.

[0145] In addition to the topography, the nonwoven materials manufactured according to the present disclosure can also be produced using fiber blends and methods that can form not only the topography but also create a nonwoven substrate with other optimal properties, including porosity or void volume, absorbent characteristics, and mechanical strength. Advantageously, the nonwoven web manufactured according to the present disclosure can be designed to pick up the same amount of oil and / or grease as a woven or knitted fabric but with a basis weight less than about 20% of the basis weight of conventional fabric materials, such as less than about 30%, such as less than about 40%, such as even less than about 50%.

[0146] See Figure 1 , which shows an embodiment of the nonwoven material 10 manufactured according to the present disclosure. As shown, the nonwoven material 10 includes a pattern of raised elements. In Figure 1 the embodiment shown, for example, the pattern includes a first raised pattern element 12 and a second raised pattern element 14. The first raised pattern element 12 has a perimeter greater than the perimeter of the second raised pattern element 14. In this embodiment, the first raised pattern element 12 is located in a domain consisting of columns and rows. The domain of the first raised pattern element 12 is spaced apart by a grid pattern of the second raised pattern element 14. As described in more detail below, this pattern is merely exemplary and can consist of only one of a plurality of various patterns that can be manufactured according to the present disclosure. Additionally, other patterns can include only a single raised pattern element size or can include more than two raised elements with different sizes.

[0147] As Figure 1 shown, in one aspect, the raised elements can include discrete shapes that are not interconnected. In Figure 1 the embodiment shown, the raised elements have a cylinder-like shape with a top surface that is generally circular. Figure 1The circular shape shown can provide various advantages and benefits when used for picking up grease and / or oil. However, in other embodiments, the shape of the raised elements can vary. For example, the shape of the raised elements can be irregular or can have any suitable geometric shape, such as rectangular, triangular, oval, and so on. In one aspect, discrete shapes can be combined with elongated interconnected shapes. For example, discrete, individual shapes can be combined with a grid-like raised pattern.

[0148] As Figure 1 shown, the pattern of raised elements forms void regions 16 on the base surface 20 of the nonwoven material 10. The void regions 16 and the base surface 20 can be, for example, substantially planar. The raised pattern elements 12 and the raised pattern elements 14 can extend from the base surface 20.

[0149] Between and around the first raised pattern element 12 and the second raised pattern element 14 are void regions 16. These void regions create a volume of spaced-apart void surface regions between the base surface 20 and the tops of the raised pattern elements 12 and the raised pattern elements 14. The amount and spacing of these void regions 16 can have an impact and can affect the ability of the nonwoven material 10 to clean and hold grease and / or oil substances. As Figure 1 shown, the void regions 16 on the base surface 20 can have different sizes and shapes. For example, larger void regions can create contaminant retention zones 18. In some embodiments, the contaminant retention zones 18 can provide a surface area for holding and retaining contaminants. The contaminant retention zones 18 can also improve the liquid absorption properties of the nonwoven material 10 in certain applications. In Figure 1 the embodiment shown, the contaminant retention zones 18 are not interconnected but are instead spaced apart by the second raised pattern element 14. However, in other embodiments, the contaminant retention zones 18 can be interconnected and form a grid on the surface of the nonwoven material 10.

[0150] The raised pattern elements 12 and the raised pattern elements 14 can have any suitable size, as long as the raised elements create an edge sufficient to exert a cleaning effect. Generally, the raised pattern elements can have a perimeter greater than about 0.5 mm, such as greater than about 0.75 mm, such as greater than about 1 mm, such as greater than about 1.5 mm, such as greater than about 2 mm, such as greater than about 2.5 mm, such as greater than about 2.75 mm, such as greater than about 3 mm. The perimeter of the raised pattern elements is generally less than about 20 mm, such as less than about 10 mm, such as less than about 7 mm, such as less than about 5 mm, such as less than about 3 mm, such as less than about 2.5 mm, such as less than about 2 mm, such as less than about 1.75 mm. As Figure 1As shown, the nonwoven material 10 can include raised pattern elements having different sizes. For example, in one aspect, the first raised pattern element 12 can have a perimeter of from about 1 mm to about 2.5 mm, while the second raised pattern element 14 can have a perimeter of from about 0.5 mm to about 1.5 mm.

[0151] Within each pattern domain, the raised pattern elements can be spaced apart a distance to create sufficient void area 16 while also creating sufficient edges of the raised pattern elements. The spacing from the edge of one raised element to the edge of an adjacent raised element can be measured along a line intersecting the center of each raised element. The spacing between raised elements within a domain or pattern area can generally be greater than about 0.2 mm, such as greater than about 0.3 mm, such as greater than about 0.5 mm, such as greater than about 0.7 mm, such as greater than about 0.9 mm, such as greater than about 1.1 mm, such as greater than about 1.3 mm, such as greater than about 1.5 mm, such as greater than about 1.7 mm, such as greater than about 1.9 mm, such as greater than about 2.1 mm, such as greater than about 2.3 mm. The spacing between adjacent pattern elements is generally less than about 5 mm, such as less than about 4 mm, such as less than about 3 mm, such as less than about 2.75 mm, such as less than about 2.5 mm, such as less than about 2.25 mm, such as less than about 2 mm, such as less than about 1.8 mm, such as less than about 1.6 mm, such as less than about 1.4 mm, such as less than about 1.2 mm, such as less than about 1 mm, such as less than about 0.8 mm.

[0152] The height of the raised pattern element can be measured at a pressure of 0.05 psi and can be measured from the top to the bottom surface 20 of the pattern element. The height of the raised element can be uniform or can vary across the surface of the nonwoven web. Generally, the height of the raised element can be greater than about 0.2 mm, such as greater than about 0.5 mm, such as greater than about 0.7 mm, such as greater than about 0.9 mm, such as greater than about 1.1 mm. The height of the raised element is generally less than about 2 mm, such as less than about 1.7 mm, such as less than about 1.5 mm, such as less than about 1.3 mm, such as less than about 1.2 mm, such as less than about 1.1 mm, such as less than about 1 mm, such as less than about 0.9 mm, such as less than about 0.8 mm, such as less than about 0.7 mm.

[0153] As Figure 1As shown, the raised pattern elements 12 and 14 occupy a certain amount of surface area relative to the void area 16. The surface area can be varied and controlled according to the type of application for which the nonwoven web 10 will be used. Generally, the raised pattern elements 12 and 14 occupy more than about 8% of the total surface area, such as more than about 10% of the total surface area, such as more than about 15% of the total surface area, such as more than about 20% of the total surface area, such as more than about 25% of the total surface area, such as more than about 30% of the total surface area, such as more than about 35% of the total surface area, such as more than about 40% of the total surface area, such as more than about 45% of the total surface area, such as more than about 50% of the total surface area, such as more than about 55% of the total surface area, such as more than about 60% of the total surface area, such as more than about 65% of the total surface area. The raised elements generally occupy less than about 80% of the total surface area of the nonwoven material 10, such as less than about 75% of the total surface area, such as less than about 70% of the total surface area, such as less than about 65% of the total surface area, such as less than about 60% of the total surface area, such as less than about 55% of the total surface area, such as less than about 50% of the total surface area, such as less than about 45% of the total surface area, such as less than about 40% of the total surface area.

[0154] The fibers used to form the nonwoven material 10 can also vary according to the particular application. The fibers incorporated into the nonwoven material 10 can include, for example, individual cellulose fibers, individual synthetic polymer fibers, or a mixture of cellulose fibers and synthetic polymer fibers.

[0155] Cellulose fibers that can be incorporated into the material include, but are not limited to, non-wood fibers (including bast fibers), such as cotton, manila hemp, kenaf, Indian grass, flax, thatch, straw, jute, bagasse, milkweed floss, and pineapple leaf fibers; and wood or pulp fibers, such as those obtained from hardwoods and softwoods, including softwood fibers, such as northern and southern softwood kraft fibers; hardwood fibers, such as eucalyptus, maple, birch, and aspen. The pulp fibers can be prepared in high-yield or low-yield form and can be pulped by any known method (including kraft, sulfite, high-yield pulping methods) and other known pulping methods. Fibers prepared by organic solvent pulping methods can also be used. The cellulose pulp fibers described above can have an average fiber length of less than about 8 mm, such as less than about 6 mm, such as less than about 4 mm, for example. The average fiber length of the cellulose pulp fibers is generally greater than about 1 mm, such as greater than about 2 mm, such as greater than about 3 mm.

[0156] Other cellulose fibers that can be incorporated into the material include any suitable regenerated cellulose fibers, including rayon fibers, viscose fibers, modal fibers, lyocell fibers, and the like. Regenerated cellulose fibers, cotton fibers, and various other bast fibers can generally have a longer fiber length than pulp fibers. For example, the fibers can include staple fibers and can have a fiber length of from about 8 mm to about 70 mm. The fiber length can be, for example, greater than about 10 mm, such as greater than about 12 mm, such as greater than about 14 mm, and generally less than about 60 mm, such as less than about 50 mm, such as less than about 40 mm, such as less than about 30 mm.

[0157] As described above, the nonwoven material 10 can contain separate synthetic polymer fibers or a combination of synthetic polymer fibers and cellulose fibers. The synthetic polymer fibers can include any suitable fibers, including polyester fibers, nylon fibers, polyolefin fibers, and the like. The synthetic polymer fibers can include virgin fibers, regenerated fibers, or a mixture thereof.

[0158] The synthetic polymer fibers (such as polyester fibers) can have any suitable size. In one embodiment, relatively fine fibers are used. For example, the synthetic polymer fibers can have a denier of less than about 10, such as less than about 8, such as less than about 6, such as less than about 5, such as less than about 4, such as less than about 3, such as less than about 2. In one aspect, the synthetic polymer fibers can have a denier of from about 0.8 to about 2.5, such as from about 1 to about 2. In an alternative embodiment, the synthetic polymer fibers can have a denier of less than about 1.5, such as less than about 1.3, such as less than about 1, such as less than about 0.8, and generally greater than about 0.3.

[0159] In one aspect, all of the synthetic polymer fibers contained in the nonwoven material can have the same size. In an alternative embodiment, a mixture of different synthetic polymer fibers can be incorporated into the nonwoven material. In one aspect, for example, the nonwoven material can contain a first polyester fiber having a size greater than that of a second polyester fiber. The first polyester fiber can have, for example, a size of from about 0.5 denier to about 5 denier, such as from about 0.8 denier to about 1.5 denier. In another aspect, the second polyester fiber can have a denier of less than about 1.5, such as less than about 1.2, such as less than about 1.0, and generally greater than about 0.5, such as greater than about 0.7.

[0160] In one embodiment, the nonwoven material 10 can be made entirely of cellulose fibers. The cellulose fibers can include all the same fibers or can include a blend or mixture of different cellulose fibers. For example, the nonwoven material can contain a combination of cellulose pulp fibers with cotton fibers, regenerated cellulose fibers, bast fibers, or mixtures thereof.

[0161] Alternatively, the nonwoven material can be made entirely of synthetic polymer fibers (such as polyester fibers). The nonwoven material can contain a single synthetic polymer fiber or can contain a mixture of different synthetic polymer fibers. As described above, in one embodiment, the nonwoven material can be made of two different types of polyester fibers having different sizes. The fiber length can also vary. Generally, the synthetic polymer fibers are staple fibers that can have any length as needed. Generally, the length of the fibers is usually less than about 100 mm, such as less than about 50 mm, such as less than about 30 mm, such as less than about 20 mm, such as less than about 15 mm. The fiber length is usually greater than about 3 mm, such as greater than about 5 mm, such as greater than about 8 mm. In one aspect, longer fibers with a length greater than about 15 mm, such as greater than about 25 mm, can be used.

[0162] In one embodiment, the nonwoven material 10 can be made of a mixture of cellulose fibers and synthetic polymer fibers. The cellulose fibers and / or synthetic polymer fibers can include any of the fibers described above or any of the fiber mixtures described above. The cellulose fibers can generally be present in the nonwoven web in an amount greater than about 10 wt%, such as greater than about 20 wt%, such as greater than about 30 wt%, such as greater than about 35 wt%, such as greater than about 40 wt%, such as greater than about 45 wt%, such as greater than about 50 wt%, such as greater than about 55 wt%, such as greater than about 60 wt%, such as greater than about 65 wt%, such as greater than about 70 wt%, such as greater than about 75 wt%. The cellulose fibers can generally be present in the nonwoven material in an amount less than about 95 wt%, such as less than about 90 wt%, such as less than about 85 wt%, such as less than about 80 wt%, such as less than about 70 wt%, such as less than about 60 wt%, such as less than about 50 wt%, such as less than about 40 wt%, such as less than about 30 wt%.

[0163] Synthetic polymer fibers can be present in the nonwoven material 10 in an amount greater than about 5 wt%, such as in an amount greater than about 10 wt%, such as in an amount greater than about 15 wt%, such as in an amount greater than about 20 wt%, such as in an amount greater than about 25 wt%, such as in an amount greater than about 30 wt%, such as in an amount greater than about 35 wt%, such as in an amount greater than about 40 wt%, such as in an amount greater than about 45 wt%. Synthetic polymer fibers can generally be present in the nonwoven material 10 in an amount less than about 85 wt%, such as in an amount less than about 80 wt%, such as in an amount less than about 70 wt%, such as in an amount less than about 60 wt%, such as in an amount less than about 55 wt%, such as in an amount less than about 50 wt%, such as in an amount less than about 45 wt%, such as in an amount less than about 40 wt%, such as in an amount less than about 30 wt%, such as in an amount less than about 15 wt%, such as in an amount less than about 10 wt%.

[0164] In one particular embodiment, the nonwoven material 10 comprises from about 40 wt% to about 60 wt% of cellulosic pulp fibers, such as softwood fibers and / or hardwood fibers, and contains from about 40 wt% to about 60 wt% of polyester fibers. The polyester fibers can include a first polyester fiber having a size of about 1 denier to about 2 deniers and a second polyester fiber having a size of about 0.3 denier to about 0.8 deniers.

[0165] In some embodiments, a binder material can be incorporated into the nonwoven material. Binder materials useful in the present disclosure can include, but are not limited to, thermoplastic binder fibers, such as PET / PE bicomponent binder fibers, and water-compatible adhesives or wet strength agents, such as latex. In some embodiments, the binder material used herein can be in powder form, such as, for example, thermoplastic PE powder. Importantly, the binder can include a binder that is insoluble in water on the dry substrate. In certain embodiments, the latex used in the present disclosure can be cationic or anionic to facilitate application and adhesion to the cellulosic fibers that can be used herein. For example, latexes considered suitable include, but are not limited to, anionic styrene-butadiene copolymers, polyvinyl acetate homopolymers, vinyl acetate-ethylene copolymers, vinyl acetate-acrylic acid copolymers, ethylene-vinyl chloride copolymers, ethylene-vinyl chloride-vinyl acetate terpolymers, acrylic polyvinyl chloride polymers, acrylic polymers, nitrile polymers, and other suitable anionic latex polymers known in the art. Examples of such latexes are described in US4785030 to Hager, US6462159 to Hamada, and US6752905 to Chuang et al., which patents are incorporated herein by reference.

[0166] Examples of other wet strength agents include polyaldehyde functional compounds such as glyoxylated polyacrylamides, such as cationic glyoxylated polyacrylamides. Such compounds include the PAREZ 631NC wet strength resin available from Cytec Industries of West Patterson, N.J., glyoxylated polyacrylamide, and HERCOBOND 1366 manufactured by Hercules, Inc. of Wilmington, Del. Another example of a glyoxylated polyacrylamide is PAREZ 745, which is a glyoxylated poly(acrylamide-co-diallyldimethylammonium chloride).

[0167] Examples of suitable thermoplastic binder fibers include, but are not limited to, single-component and multi-component fibers having at least one relatively low melting point thermoplastic polymer such as polyethylene. In certain embodiments, polyethylene / polypropylene sheath / core staple fibers may be used. The binder fibers may have a length consistent with that described above for staple fibers. The binder fibers may be present in the nonwoven web in an amount greater than about 2 wt%, such as greater than about 5 wt%, such as greater than about 8 wt%, and less than about 40 wt%, such as less than about 30 wt%, such as less than about 20 wt%, such as less than about 10 wt%.

[0168] See Figure 2 , which shows another embodiment of the nonwoven material 10 manufactured in accordance with the present disclosure. Like reference numerals are used to indicate like elements. In Figure 2 the embodiment shown, the nonwoven material 10 includes raised elements 12 extending from a base surface 20. Void regions 16 are located between and around the raised elements 12. The raised elements 12 are organized into domains separated by contaminant retention zones 18. The contaminant retention zones 18 forming part of the void regions 16 are interconnected and form a grid-like pattern in Figure 2 the embodiment shown. The grid pattern is obliquely or diagonally oriented with respect to the longitudinal direction of the nonwoven material 10.

[0169] In Figure 2 the embodiment shown, all of the raised elements 12 generally have the same height and perimeter. However, the raised pattern elements 12 may occupy a similar amount of surface area compared to the raised elements 12 and raised elements 14 as shown in Figure 1 .

[0170] In accordance with the present disclosure, the nonwoven material 10 can be configured to significantly improve the cleaning efficiency against all different types of contaminants. The nonwoven materials of the present disclosure are particularly suitable for wiping and retaining grease and / or oil. As shown in Figure 1 and Figure 2As shown, the nonwoven web has a controlled topography including a pattern of raised elements. The perimeter or circumference of each raised element forms an edge that has been found to improve the cleaning properties of the nonwoven material. More specifically, the edge of the raised element acts in concert with the void surface area located between the base surface and the top of the raised element to engage and capture contaminants. Additionally, the fibers used to form the nonwoven material 10 and the manner in which the nonwoven material 10 is constructed can also improve the cleaning properties. For example, the topography of the nonwoven material 10 can be configured to maintain its structure during use, such as when pressure is applied to the nonwoven material to cause it to conform to an adjacent surface. In this regard, various parameters of the nonwoven material 10 can be measured under pressures that simulate the pressures applied to the nonwoven material during use. For example, see Figure 3 , which shows a cross-section of the nonwoven material 10 as Figure 2 shown. The nonwoven material 10 includes raised elements 12 extending from a base surface 20. Void regions are created between and around the raised elements 12.

[0171] See Figure 3 , which shows the nonwoven material 10 conforming to an adjacent surface 52. Arrow 50 represents the pressure applied to the nonwoven material 10, such as the pressure applied when the nonwoven material 10 is used as a wipe. According to the present disclosure, various properties of the nonwoven material 10 are determined when a simulated surface pressure is applied to the raised elements 12 of the nonwoven material 10.

[0172] For example, two properties that are believed to have an impact on the ability of the nonwoven material to remove contaminants are the perimeter of the pattern elements and the pattern-formed void volume. Each of these parameters can be measured at a desired pressure, such as pressures of 0.1 psi, 0.3 psi, 0.4 psi, and so on. In one aspect, the measurement can be made when a pressure of 0.3 psi is applied to the nonwoven material.

[0173] The perimeter of the pattern elements refers to the total distance around the edges of the raised elements 12. In other words, the perimeter of the pattern elements is the sum of all the perimeters around all the raised elements contained in the nonwoven material. As described above, the edges of the raised elements are believed to contribute to the ability of the nonwoven material to engage and pick up contaminants. The perimeter of the pattern elements can be normalized per unit area. In one aspect, when tested at a pressure of 0.3 psi, the perimeter of the pattern elements per unit area on the nonwoven material can be greater than about 0.08 / mm (mm / mm 2 ), such as greater than about 0.09 / mm, such as greater than about 0.1 / mm, such as greater than about 0.11 / mm, such as greater than about 0.12 / mm, and typically less than about 0.3 / mm, such as less than about 0.2 / mm, such as less than about 0.18 / mm, such as less than about 0.16 / mm.

[0174] Another property measured under pressure is the pattern-forming void volume, which refers to the void region 16 as shown in Figure 1 and Figure 2 and can be measured from the base surface 20 to the top of the raised pattern element 14. This void volume, especially at the pressure used, creates space to accumulate contaminants that contact the edges of the raised elements. When measured at 0.3 psi, the nonwoven material manufactured according to the present disclosure can exhibit a pattern-forming void volume per unit surface area greater than about 1.1 mm, such as greater than about 1.2 mm, such as greater than about 1.3 mm, such as greater than about 1.4 mm, such as greater than about 1.5 mm, such as greater than about 1.6 mm, and generally less than about 3 mm, such as less than about 2.5 mm, such as less than about 2.2 mm, such as less than about 2 mm.

[0175] Other parameters that can affect the cleaning properties of the nonwoven web include the void volume of the nonwoven web. This parameter determines the amount of open space within the gaps of the nonwoven web. The void volume of the nonwoven web (which can also be referred to as the intrinsic void volume) can, for example, generally be greater than about 75%, such as greater than about 78%, such as greater than about 80%, such as greater than about 82%, and generally less than about 96%, such as less than about 90%. The void volume of the nonwoven material can be measured at a pressure, such as a pressure of 0.3 psi.

[0176] The void volume of the nonwoven web per unit surface area can be greater than about 0.2 mm (mm 3 / mm 2 ), such as greater than about 0.25 mm, such as greater than about 0.28 mm, such as greater than about 0.3 mm, such as greater than about 0.31 mm, and less than about 0.6 mm, such as less than about 0.55 mm, such as less than about 0.5 mm, such as less than about 0.45 mm, such as less than about 0.4 mm. The void volume or porosity of the nonwoven web can be adjusted and controlled according to the fibers used to form the web and the process of web formation.

[0177] When tested at a pressure of 0.05 psi, the nonwoven material manufactured according to the present disclosure can generally have a density greater than about 0.1 g / cm 3 . The density of the nonwoven web can, for example, be greater than about 0.12 g / cm 3 , and less than about 2 g / cm 3 , such as less than about 1.8 g / cm 3 , such as less than about 0.14 g / cm 3 .

[0178] The thickness of the web can generally be from about 0.4 mm to about 3 mm, including all 0.1 mm increments therebetween. For example, the thickness of the web can be greater than about 0.5 mm, such as greater than about 0.6 mm, such as greater than about 0.8 mm. The thickness can be less than about 1.8 mm, such as less than about 1.6 mm, such as less than about 1.5 mm, such as less than about 1.3 mm, such as less than about 1.1 mm, such as less than about 1 mm. The thickness can be measured when applying a pressure of 0.05 psi.

[0179] The basis weight of the nonwoven material made according to the present disclosure can be any value from about 20 gsm to about 500 gsm, including all 1 gsm increments therebetween. However, in many applications, the basis weight can be relatively low. Specifically, the basis weight of the nonwoven material made according to the present disclosure can be much smaller than that of a conventional cloth material, but still has the same cleaning ability for many contaminants such as grease and oil. For example, in one aspect, the basis weight can be less than about 120 gsm, such as less than about 100 gsm, such as less than about 90 gsm, such as less than about 80 gsm, such as less than about 75 gsm, such as less than about 70 gsm, such as less than about 65 gsm. The basis weight is generally greater than about 25 gsm, such as greater than about 35 gsm, such as greater than about 40 gsm, such as greater than about 45 gsm, such as greater than about 50 gsm.

[0180] As Figure 3 shown, the raised elements of the nonwoven material can be formed using various processes. In Figure 3 the embodiment shown, the raised element 12 is shown to have a greater basis weight than a portion of the nonwoven material corresponding to the void region 16. For example, the raised region can have a basis weight greater than about 10% of the basis weight of the base surface of the nonwoven material, such as greater than about 20%, such as greater than about 30%, such as greater than about 40%, such as greater than about 50%, such as greater than about 60%. The basis weight of the raised region can be up to about 100% greater than the basis weight of the base surface, such as up to about 90% greater than the basis weight of the base surface.

[0181] As Figure 1 and Figure 2 shown, the nonwoven material can be made in a variety of ways. For example, the nonwoven material can be made according to a wet-laid process, an air-laid process, a foam forming process, and the like. The raised elements and topography can be produced using various different techniques such as hydroentangling and / or applying pressure or suction to the web on a patterned forming surface.

[0182] In one embodiment, for example, the nonwoven materials of the present disclosure are produced according to a foam forming process. The foam forming process has many advantages and beneficial effects. During the foam forming process, foam is used instead of water as the carrier for the fibers forming the web. The foam, which represents a large amount of air, is blended with cellulose and / or synthetic polymer fibers. Since less water is used to form the web, less energy is required to dry the web. In addition, the foam forming process is more suitable for producing nonwoven materials containing different types of fibers (especially longer synthetic polymer fibers). In addition, surface topography can be incorporated into nonwoven materials similar to the embodiments as shown in Figure 3 where the raised elements have a basis weight greater than the surrounding area of the web. In addition, the foam forming process can produce a unique fiber orientation. For example, when a nonwoven material is produced from a combination of shorter fibers (such as pulp fibers) and longer fibers (such as synthetic polymer or regenerated cellulose staple fibers), the shorter fibers tend to accumulate in the raised elements, while the longer fibers can have a greater density along the base surface. This structure produces a nonwoven material with a greater fiber density and absorbency in the raised elements, while having greater strength between the raised elements.

[0183] In a specific embodiment, as shown in Figure 4 and Figure 5 for illustrative purposes only, the nonwoven materials of the present disclosure can be produced using a combination of a foam forming process and a hydroentangling step that produces raised elements. The hydroentangling step can occur, for example, on a patterned forming surface that matches the pattern or topography of the resulting nonwoven material.

[0184] First, a fiber furnish for producing the nonwoven material is selected. As described above, the fiber furnish can contain only cellulose fibers, only synthetic polymer fibers, or a mixture of the two. During foam forming, the fiber furnish is combined with foam produced by blending water with a foaming agent.

[0185] The foaming agent can include, for example, any suitable surfactant. In one embodiment, for example, the foaming agent can include sodium lauryl sulfate, which is also known as sodium lauryl polyoxyethylene ether sulfate or sodium lauryl ether sulfate. In one embodiment, the foaming agent is a nonionic surfactant, which can include alkyl polyglycoside. For example, the foaming agent can be C8 alkyl polyglycoside, C10 alkyl polyglycoside, or a mixture of C8 and C10 alkyl polyglycosides.

[0186] Other foaming agents include sodium dodecyl sulfate or ammonium lauryl sulfate. In other embodiments, the foaming agent can include any suitable cationic and / or amphoteric surfactants. For example, other foaming agents include fatty amine, amide, amine oxide, fatty acid quaternary compounds, etc.

[0187] Blowing agents are typically combined with water in an amount greater than about 0.1 wt%, such as greater than about 1 wt%, such as greater than about 2 wt%, such as greater than about 3 wt%. One or more blowing agents are typically present in an amount less than about 50 wt%, such as less than about 10 wt%, such as less than about 8 wt%, such as less than about 4 wt%.

[0188] Once the blowing agent and water are combined, the mixture is blended or otherwise subjected to forces capable of forming a foam. A foam generally refers to a porous matrix that is an aggregate of hollow units or bubbles that can be interconnected to form channels or capillaries.

[0189] The foam density can vary depending on the specific application and various factors, including the fiber furnish used. In one embodiment, for example, the foam density of the foam can be greater than about 200 g / L, such as greater than about 250 g / L, such as greater than about 300 g / L. The foam density is typically less than about 600 g / L, such as less than about 500 g / L, such as less than about 400 g / L, such as less than about 350 g / L. In one embodiment, for example, a lower density foam having a foam density typically less than about 350 g / L, such as less than about 340 g / L, such as less than about 330 g / L is used. The air content of the foam will generally be greater than about 30%, such as greater than about 40%, such as greater than about 50%, such as greater than about 60%. The air content is typically less than about 80 vol%, such as less than about 70 vol%, such as less than about 65 vol%.

[0190] To form a nonwoven web, the foam is combined with a selected fiber furnish and any adjuvants. The foamed suspension of fibers is then pumped into a tank and fed from the tank into a headbox. Figure 4 and Figure 5 For example, an embodiment of a method for forming a web according to the present disclosure is shown. Specifically as Figure 5 shown, the foamed fiber suspension can be fed into tank 312 and then into headbox 310. The foamed fiber suspension is discharged from headbox 310 onto an endless moving forming fabric 326 supported and driven by roll 328 to form web 210. As Figure 5 shown, a forming plate 314 can be positioned below web 210 adjacent to headbox 310. Once formed on forming fabric 326, the foam-formed web can have a consistency less than about 50%, such as less than about 20%, such as less than about 10%, such as less than about 5%. In fact, the forming consistency can be less than about 2, such as less than about 1.8, such as less than about 1.5. The forming consistency is generally greater than about 0.5, such as greater than about 0.8. The forming consistency represents the ability to produce a web according to the present disclosure while minimizing the amount of water required during forming.

[0191] Once a wet web is formed on the forming fabric 326, the web is conveyed downstream and dewatered. For example, the method may optionally include a plurality of vacuum devices 316, such as vacuum boxes and vacuum rolls. The vacuum boxes assist in removing moisture from the newly formed web 210.

[0192] As Figure 5 shown, the forming fabric 326 may also be placed in communication with a steam box 318 located above a pair of vacuum rolls 320. The steam box 318 can, for example, significantly increase dryness and reduce cross - machine moisture variation. The steam applied from the steam box 318 heats the moisture in the wet web 210 such that the water in the web is more easily drained, especially when combined with the vacuum rolls 320. In Figure 4 the illustrated embodiment, the newly formed web 210 is conveyed downstream from the forming fabric 326, subjected to hydroentanglement, and dried on a through - air dryer.

[0193] After the foamed - formed web is produced, the web is subjected to one or more hydroentanglement steps. In Figure 5 the illustrated embodiment, for example, the web 210 undergoes two different hydroentangling steps. Specifically, in Figure 5 it, the web 210 is hydroentangled on a first surface during a first hydroentangling step and then, during a second hydroentangling step, on an opposite second surface. As Figure 5 shown, for example, the process may include a first hydroentangling device 330 and a second hydroentangling device 332. The hydroentanglement occurring at each hydroentanglement station can be accomplished using conventional hydroentangling equipment. The hydroentanglement of the foamed - formed web can be carried out with any suitable working fluid, such as water. The working fluid flows through a manifold that distributes the fluid evenly into a series of individual holes or orifices. For example, the exemplary holes or orifices can have a diameter of from about 0.003 inches to about 0.015 inches. For example, the manifold may include an orifice bar with a diameter of 0.007 inches. The manifold may contain from about 20 to about 40 holes per inch and may include 1 to 3 rows of holes. Many other manifold configurations and combinations can be used. In Figure 5 the illustrated embodiment drawing, for example, the hydroentangling device 330 includes a plurality of injectors 334, while the hydroentangling device 332 includes a plurality of injectors 336. The injectors 334 and 336 can be part of the manifold and can be in communication with a source of working fluid.

[0194] In the hydroentanglement process, the working fluid can pass through the orifices at a pressure in the range of from about 200 psig to about 3,500 psig. At the upper limit of the pressure range, it is contemplated to process the web at a speed of from about 500 ft to about 2000 ft. The fluid impinges on the material or web that may be supported on a porous surface or wire or may be supported on a porous drum surface. In Figure 5In the illustrated embodiment, for example, hydroentangling occurs on the first cylinder 338 and the second cylinder 340.

[0195] During hydroentangling, the web 210 can be placed directly on the surface of the cylinder 338 and on the surface of the cylinder 340. Each cylinder can include a plurality of openings or vacuum channels for draining excess water. During the hydroentangling process, these openings or vacuum channels can also form a pattern in the web 210. For example, a pattern can be formed into one surface of the web at a first hydroentangling station, and a pattern can be formed into the second opposite surface of the web at a second hydroentangling station. The pattern formed in each surface of the web 210 can be a pattern manufactured in accordance with the present disclosure, such as Figure 1 the pattern shown or Figure 2 the pattern shown.

[0196] In addition to forming the desired topography and improving the cleaning properties of the nonwoven material 210, one or more hydroentangling stations can also significantly improve various physical properties of the web 210, such as the integrity of the web. For example, the columnar jets of the working fluid that directly impact the surface of the web are used to entangle and wind the fibers contained in the web, especially loose yarn segments and loose fibers. The hydroentangling process ultimately forms a coherent entanglement matrix. The hydroentangling step is also further used to produce a substantially homogeneous fiber mixture within the web. For example, the resulting hydroentangled web is "non-stratified" and does not contain distinguishable separate fiber layers through the thickness of the web.

[0197] Once the foam-formed web 210 has been hydroentangled one or more times, a non-compressive drying operation can be used to dry the web. For example, as Figure 4 shown, a through-air dryer can be used to dry the foam-formed web.

[0198] See Figure 4 , the foam-formed and hydroentangled web 210 is transferred from the cylinder 340 to the through-air drying fabric 344 by means of a vacuum transfer roll 346 or a vacuum transfer shoe. If desired, the through-air drying fabric can be run at a slower speed than the web 210 to further enhance stretching. The transfer can be carried out with vacuum assistance to ensure that the sheet deforms to conform to the through-air drying fabric, thereby producing the desired bulk and appearance when needed.

[0199] In Figure 4 the illustrated embodiment, the foam-formed web 210 is transferred to the through-air drying fabric 344. Alternatively, the foam-formed web can be conveyed to a metal porous sleeve that forms the circumference of the through-air dryer 348. Using a metal sleeve instead of a fabric can provide various advantages. For example, the porous metal sleeve can further create porosity to increase the liquid absorption properties of the web.

[0200] Alternatively, the foam-formed web 210 can be conveyed on the through-drying fabric 344 around the circumference of the through-dryer 348. The through-drying fabric can contain tall and long embossments. For example, the through-drying fabric can have from about 5 to about 300 embossments per square inch that protrude at least about 0.005 inches above the plane of the fabric. During drying, the web can be further macroscopically aligned to conform to the surface of the through-drying fabric. However, a flat surface can also be used in the present disclosure.

[0201] The side of the web that contacts the through-drying fabric is commonly referred to as the "fabric side" of the nonwoven web. As described above, the fabric side of the nonwoven web can have a shape that conforms to the surface of the through-drying fabric after the fabric is dried in the through-dryer. On the other hand, the opposite side of the nonwoven web is commonly referred to as the "air side". In a normal through-drying process, the air side of the web is generally smoother than the fabric side.

[0202] The vacuum level for web transfer can be from about 3 to about 15 inches of mercury (75 to about 380 millimeters of mercury), preferably about 5 inches (125 millimeters) of mercury. The vacuum shoe or roll (negative pressure) can be supplemented or replaced by using positive pressure from the opposite side of the web to puff the web onto the next fabric, in addition to or as an alternative to, sucking the web onto the next fabric with a vacuum.

[0203] The web is finally dried by the through-dryer 348 to a consistency of about 94% or higher and then conveyed to the carrier fabric 350. The dried substrate 352 is transported to the reel 354 using the carrier fabric 350 and optionally the carrier fabric 356. An optional pressure turning roll 358 can be used to facilitate the transfer of the web from the carrier fabric 350 to the fabric 356. Carrier fabrics suitable for this purpose are Albany International 84M or 94M and Asten 959 or 937, which are relatively smooth fabrics with a fine pattern. Although not shown, reel calendering or subsequent off-line calendering can be used to improve the smoothness and softness of the substrate.

[0204] The method of the present disclosure can also produce a web having good bulk characteristics. For example, the bulk density can generally be greater than about 3 cc / g, such as greater than about 5 cc / g, such as greater than about 8 cc / g, such as greater than about 10 cc / g, such as greater than about 12 cc / g, and generally less than about 20 cc / g, such as less than about 15 cc / g.

[0205] At Figure 4 and Figure 5In the illustrated embodiment, a foamed web is hydroentangled on a patterned forming surface to form raised elements. However, in other embodiments, suction located below the forming surface can be used to form the raised elements. These processes produce raised elements that have an increased basis weight compared to the base surface of the web. Texture can also be imparted to the web by embossing. However, when the web is embossed, the basis weight of the web remains consistent and raised elements are not produced with an increase in basis weight.

[0206] The present disclosure can be better understood with reference to the following examples.

[0207] Example 1

[0208] A nonwoven material similar to the Figure 2 illustrated embodiment is manufactured in accordance with the present disclosure. The nonwoven material is manufactured by a method similar to the Figure 4 and Figure 5 illustrated methods. The fiber furnish used to produce the web contains a combination of 60 weight percent softwood pulp fibers and 40 weight percent polyester fibers. The polyester fibers comprise 50 weight percent 0.5 denier fibers and 50 weight percent 1.5 denier fibers. The raised elements cover 38.9% of the total surface area of the nonwoven web. The raised elements have a perimeter of from about 2 mm to about 2.5 mm. The contaminant retention zone on the surface of the nonwoven material has a width of about 2.15 mm.

[0209] First, the above-described web was simulated using software for determining the grease and oil cleaning performance. From the simulation, we obtained the following results:

[0210]

[0211] As shown above, the simulation was performed with raised elements of different heights. The results were normalized in terms of grams of contaminant per gram of nonwoven material. The basis weight of the input nonwoven material was 65 gsm.

[0212] From the simulation, the 65 gsm nonwoven material performs as well as a woven or knitted fabric with a higher basis weight, such as a 200 gsm basis weight.

[0213] In addition to the simulation tests, a nonwoven material with a 65 gsm basis weight was produced and various properties of the nonwoven material were tested. The tests were performed at different pressures applied to the nonwoven material. The following results were obtained:

[0214]

[0215] These and other modifications and variations of the present invention may be practiced by those of ordinary skill in the art without departing from the spirit and scope of the invention more particularly described in the appended claims. In addition, it should be understood that aspects of various embodiments may be interchanged either wholly or in part. Further, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention as further described in such appended claims.

Claims

1. A wiping product, said wiping product comprising: a nonwoven web having a first surface and an opposite second surface, said nonwoven web comprising cellulose fibers, synthetic polymer fibers, or a mixture thereof; said nonwoven web having a basis weight of less than about 110 gsm; a topography pattern located on said first surface of said nonwoven web, at least a portion of said topography pattern comprising raised pattern elements extending from a base surface; and wherein when tested at 0.3 psi, said raised pattern elements produce a unit surface area pattern element perimeter greater than about 0.08 / mm and a unit surface area pattern formation volume greater than about 1.1 mm.

2. The wiping product according to claim 1, wherein when tested at 0.3 psi, said raised pattern elements produce a unit surface area pattern element perimeter greater than about 0.09 / mm, such as greater than about 0.1 / mm, such as greater than about 0.11 / mm, such as greater than about 0.12 / mm.

3. The wiping product according to claim 1, wherein when tested at 0.3 psi, said raised pattern elements produce a unit surface area pattern formation volume greater than about 1.3 mm, such as greater than about 1.4 mm, such as greater than about 1.5 mm, such as greater than about 1.6 mm.

4. The wiping product according to claim 1, wherein when tested at 0.3 psi, said nonwoven web has a void volume greater than about 75%, such as greater than about 78%, such as greater than about 80%, such as greater than about 82%.

5. The wiping product according to claim 1, wherein said raised pattern elements have a basis weight and said base surface has a basis weight, and wherein the basis weight of said raised pattern elements is about 10%, such as greater than about 20%, such as greater than about 30%, such as greater than about 40% greater than the basis weight of said base surface.

6. The wiping product according to claim 1, wherein said raised pattern elements of the pattern comprise discrete shapes that are not interconnected.

7. The wiping product according to any one of the preceding claims, wherein said raised pattern elements comprise raised circular elements.

8. The wiping product according to claim 7, wherein the circular elements have a perimeter of about 0.5 mm to about 20 mm, such as about 0.75 mm to about 10 mm, such as about 1 mm to about 3 mm.

9. The wiping product according to any one of the preceding claims, wherein said raised pattern elements form a raised pattern zone contiguous to a contaminant retention zone, said contaminant retention zone being planar.

10. The wiping product according to claim 9, wherein said contaminant retention zones are discrete zones that are not interconnected.

11. A wiping product as claimed in any one of the preceding claims, wherein the nonwoven web has a density of from about 0.1 g / cm 3 to about 0.18 g / cm 3 , such as from about 0.12 g / cm 3 to about 0.14 g / cm 3 .

12. The wiping product according to any one of the preceding claims, wherein at least a portion of said raised pattern elements has a height greater than about 0.1 mm, such as greater than about 0.2 mm, such as greater than about 0.3 mm, such as greater than about 0.4 mm, such as greater than about 0.5 mm, such as greater than about 0.6 mm, and generally less than about 1.2 mm, such as less than about 1 mm, such as less than about 0.8 mm.

13. The wiping product according to any one of the preceding claims, wherein the raised pattern elements are spaced apart by an average distance of from about 0.5 mm to about 1.5 mm.

14. The wiping product according to any one of the preceding claims, wherein the nonwoven web has a thickness greater than about 0.4 mm, such as greater than about 0.6 mm, such as greater than about 0.8 mm, and less than about 1.3 mm, such as less than about 1.1 mm, such as less than about 1 mm.

15. The wiping product according to any one of the preceding claims, wherein the nonwoven web has a basis weight of from about 35 gsm to about 100 gsm, such as from about 50 gsm to about 90 gsm, such as from about 50 gsm to about 70 gsm.

16. The wiping product according to any one of the preceding claims, wherein the nonwoven web contains from about 15 wt% to about 60 wt% of the synthetic polymer fibers and from about 40 wt% to about 85 wt% of the cellulose fibers.

17. The wiping product according to any one of the preceding claims, wherein the nonwoven web comprises a foam-formed web.

18. The wiping product according to any one of the preceding claims, wherein the raised pattern elements cover from about 15% to about 80% of the surface area of the first surface, such as from about 20% to about 60% of the surface area of the first surface.

19. The wiping product according to any one of the preceding claims, wherein the topography pattern comprises a first raised pattern element and a second raised pattern element, and the first raised pattern element has a perimeter smaller than that of the second raised pattern element.

20. The wiping product according to any one of the preceding claims, wherein the synthetic polymer fibers comprise polyester fibers having a fiber size of from about 0.5 denier to about 3.0 denier.

21. The wiping product according to any one of the preceding claims, wherein the synthetic polymer fibers comprise a first polyester fiber and a second polyester fiber, the first polyester fiber having a fiber size of less than about 1.5 denier, and the first polyester fiber having a smaller size than the second polyester fiber.

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