Textile with Ribs on One Side, Smooth on the Other

Abstract

A stable finely knitted fabric is disclosed which includes a plurality of yarns including filaments of about 1.5 denier or less. The yarns are knitted into a fabric using a right-leaning top triangle (RTT) pattern. The fabric includes a face side having a plurality of parallel and elongated ridges and a back side having a smooth surface without elongated ridges. The fabric exhibits a wicking action from the smooth side to the ridged side of the fabric and excellent absorption. Further, the fabric may be used as a liquid applicator, when an absorbant liquid reservoir layer is added to the back side, as channels of air between the ridges increase liquid flow from the back side to the face side.

Description

TECHNICAL FIELD

This disclosure relates generally to textile fabrics, more specifically to textile fabrics that may be used for cleaning, e.g., mop heads, that include a frictional surface with a series of ribs on at least one side of the fabric and that may be smooth on the other side of the fabric or have ridges on both sides of the fabric.

BACKGROUND

There are three major classes of fabric—woven, non-woven and knitted fabrics. A woven fabric is formed by weaving. In contrast, nonwoven fabrics are fabrics made from fibers, bonded together by chemical, mechanical, heat or solvent treatment. The term nonwoven is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Nonwoven fabrics may lack strength unless densified or reinforced by a backing. When used for cleaning products such as wipes, clothes or mop heads, such nonwoven cleaning products are normally disposable. Compared to the woven and nonwoven fabrics, knitted fabrics are much more elastic, have much greater durability and can range widely in weight and thickness. Knitted fabrics are typically thicker and can be more absorbent than their woven and non-woven counterparts, which accounts for their uses as towels and cleaning cloths.

For cleaning articles, such as disposable cleaning wipes, nonwoven fabrics have been used frequently. Many nonwoven wipes are made from a composite fabric containing a mixture or stabilized matrix of thermoplastic filaments and at least one additional fabric, often called the “second fabric” or “secondary fabric”. Nonwoven webs with frictional ridges or tufts are also known in the art. For example, nonwoven webs with hollow ridges which extend outward from the surface of the nonwoven web are known. The ridges can be made by a number of processes, but are preferably formed by directly forming the nonwoven web on a surface with corresponding ridges, or by forming the nonwoven on an apertured surface with a pressure differential sufficient to draw the fibers through the apertures, thereby forming the ridges. Nonwoven webs with ridges have also been prepared by bonding a portion of the nonwoven web and leaving a portion of the nonwoven web unbonded using a compaction roll. In some cases, the ridges or tufts of a nonwoven fabric may include a mixture of a thermoplastic polymer and a secondary fabric.

Such nonwoven webs with frictional tufts, ridges or ribs are used in a variety of applications such as disposable absorbent articles, dry wipes, wet wipes, wet mops and dry mops. However, knitted fabrics with such frictional ridges are not available. Further, knitted fabrics with frictional ridges on one side and a smooth surface on the other side are also not available.

As concerns about the environment and specifically the overuse of landfills, there is a need for improved cleaning cloths and mops that are not disposable, but that are durable and reusable. Hence, improved cleaning fabrics that are knitted or woven, as opposed to nonwoven fabrics, are needed.

SUMMARY OF THE DISCLOSURE

A knitted fabric with frictional ridges for cleaning devices is disclosed. The knitted structure of the fabric imparts durability and strength as well as softness. The frictional ridges enhance the cleaning/scrubbing ability of the knitted fabric.

In an embodiment, a stable knitted fabric is disclosed which comprises a face side comprising a plurality of parallel and elongated ridges and a back side comprising a smooth surface without elongated ridges. As an alternative, both sides may include the elongated ridges.

In another embodiment, a stable, finely knitted fabric is disclosed which comprises a plurality of yarns comprising filaments having thicknesses of about 1.5 denier or less with the yarns having thicknesses ranging from about 50 to about 250 denier. The fibers may be made by any process for making micro-denier fibers including “Island in the Sea”, bicomponent, electrospinning (nanofiber), etc. The yarns are knitted into the fabric using a right-leaning top triangle (RTT) stitch illustrated below. The fabric comprises a face side comprising a plurality of elongated ridges and a back side comprising a smooth surface without elongated ridges.

A covered sponge is also disclosed which comprises a sponge enclosed within a knitted cover. The knitted cover is at least partly fabricated from a stable knitted fabric comprising a face side comprising a plurality of parallel and elongated ridges and a back side comprising a smooth surface without elongated ridges. The smooth back side may enhance wicking between the sponge and the ridged front side.

In any one or more of the embodiments described above, the fabric comprises a right-leaning top triangle (RTT) stitch illustrated below.

In any one or more of the embodiments described above, the fabric may comprise fibers made from polymers consisting of, for example, polyesters, polyamides, polyethylene terephthalate and combinations thereof.

A method of making a knit fabric is also disclosed which comprises forming a plurality of yarns of dissimilar weights, wherein each yarn is formed by spinning fibers comprising approximately 1.50 denier or less. The method also includes forming the fabric by knitting the plurality of yarns of dissimilar weights to have ridges extending in the direction of the knitting.

In a refinement, the forming of the fabric further comprises knitting the plurality of yarns of dissimilar weight to provide the knitted ridges.

In another refinement, the forming of the plurality of yarns of dissimilar weights further comprises forming at least some yarns of dissimilar weights from bi-component splittable filaments.

In another refinement, the forming of the plurality of yarns of dissimilar weights comprising forming a plurality of yarns of dissimilar weights from micro-denier fibers.

In another refinement, the knitting of the plurality of yarns of dissimilar weights to have knitted ridges further comprises knitting the yarns at imaginary intersection points of a grid such that a first yarn skips the grid and is knitted every other grid, a second yarn is knitted every grid, and a third yarn is knitted in rows along the grid to form the ridges on the front side of the fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic line diagram illustrating a prior art knitted stitch or pattern.

FIG. 2 is a schematic line diagram illustrating a disclosed RTT knitted stitch or pattern.

FIG. 3 is a plan view of a disclosed fabric made with the RTT pattern of FIG. 2.

FIG. 4 is another plan view of the disclosed fabric of FIG. 3.

FIG. 5 is a flow diagram illustrating the knitting of disclosed cleaning articles using the RTT pattern of FIGS. 2-4.

FIG. 6 is a more detailed flow diagram illustrating the knitting of disclosed cleaning articles using the RTT pattern of FIGS. 2-4.

FIG. 7 illustrates the face side of the disclosed knitted fabric.

FIG. 8 illustrates both the face and back sides of the disclosed knitted fabric.

DETAILED DESCRIPTION

FIGS. 1 and 2 provide a convenient comparison of a prior art weft pattern 10 (FIG. 1) and the disclosed, more complex RTT pattern fabric 20 (FIG. 2). The fabric 20 of FIG. 2 is a warp structure. The warp structure of FIG. 2 can be fabricated using the methods of FIGS. 5-6 and the detailed description of FIGS. 2-4 provided below.

A fine microfiber fabric 20 with low drag is accomplished using ridges 26 (FIGS. 4 and 7-9) on one side 28 of the microfiber fabric. The ridges 26 allow a wipe cloth or mop head to avoid dragging or sticking to a surface when wiped on a surface. The poor absorbency of polyesters and other polymer fibers has also been addressed. The ridges 26 in the micro-denier fiber fabric 20 enhance the absorbency of the fabric 20.

Specifically, it has been discovered by applicant that a capillary action results from spaces between the knit filaments. Specifically, a smaller tube has more capillary action. And smaller tubes allow more tubes on a fabric of a given size. The ridges 26 reduce the drag caused by suction or capillary suction or the possible drag caused by the micro-denier fibers binding or snagging on irregularities in the surface. Without being bound by any particular theory, it is believed these ridges 26 reduce the surface tension of any liquid being wiped on a surface by the fabric 20. It is also believed that the ridges 26 might break the surface tension of any liquid. Channels 27 for air are provided between the ridges 26 (FIG. 4) so that any suction does not cause as much drag since the fabric 20 and liquid is riding on some of the air in the channels 27. Previously there was little or no air. This is particularly true when wiping in the direction of the ridges 26, rather than wiping against the ridges 26 (perpendicular to the ridges 26).

The disclosed fabric 20 is an improved liquid applicator. Specifically, the ridges 26 on the fabric 20, when placed against a dry surface, may create channels 27 of air that urge an increased flow of liquid from the fabric 20 to the surface being cleaned. As an alternative embodiment, an absorptive layer, such as a sponge 36 (FIGS. 7-9) may be added on the back side 35 opposite the ridges 26 to act as a fluid reservoir. By placing the ridges 26 in a microfiber fabric 20, both high absorption and low drag when wiping are achieved.

A microfiber is defined as approximately 1.0 denier or below but greater than 0.3 denier. Example applications are towels, upholstery, flat mops, isolator covers and wipers or cleaning cloths. An additional problem addressed by the disclosed fabric 20 is that, by reducing friction, the pad is not twisted or pulled off of a mop frame as prior art mop pads are prone to do. Further, while the fabric 20 made of micro-denier blended yarn has significantly greater effective surface area, the ridges 26 reduce the amount of micro-denier fiber in contact with the surface being cleaned or prepared. The fabric 20 also has less effective surface area as a pad or surface in contact with a sterile instrument.

FIG. 2 illustrates a line diagram of an example of the disclosed fabric of three types of yarns 21, 22 and 33 according to an embodiment. In FIG. 2, each yarn 21-23 is illustrated by a single line. A matrix of horizontal gridlines 24 and vertical gridlines 25 are also illustrated for reference purposes and form no part of the fabric 20. The illustrated exemplary fabric 20 exhibits high performance characteristics. The three yarns 21-23 are intertwined in a knit configuration. The yarn 21 is thicker than yarns 22 and 23. The yarns 21-23 each have a micro-denier fiber content. The yarns 21-23 are knitted at the intersection points of the horizontal gridlines 24 and vertical gridlines 25. The yarn 22 skips the grid and is knitted every other grid. The yarn 23 is knitted every grid. The thickest yarn 21 is knitted in rows along the grid to form the ridges 26 on the front side 28. This places more of the micro-denier fibers in yarn 23 on the back side 35 (FIG. 9) than the front side 28, thereby improving fluid transfer.

The fabric 20 can be knitted using a wide variety of knitting machine technologies including, but not limited to, warp knit, circular knit, superpol, and/or Jacquard or even woven on a loom. The thickest yarn 21 may be a 200 denier 384 filaments yarn of all polyester filament thickness of (0.52 denier). The medium thickness warp yarn 22 may be a bi-component, splittable filament yarn 150 with the split filaments having a thickness of about 0.13-1.00 denier or less. The yarn 23 may be a 75 denier 36 filaments (filament thickness of about 0.5 denier).

After splitting, each filament of yarn 22 results in about eight to sixteen micro-denier fibers each of about 0.13 to about 0.2 denier. The two fabrics of the bi-component yarn 22 are polyester and polyamide which is the generic name for Nylon®. The bi-component filament made of two dissimilar materials allows it to be split into micro-denier fibers.

The yarn 21 is knitted to form a ridge while the yarn 22 is knitted to form a smooth top side surface between the ridges. The yarn 22 is knitted within the fabric in a zigzag pattern and forms a smooth backside surface. The yarn 23 is knitted to form a base fabric that holds all yarns including yarns 21 and 22. This means that the ridges 26 consist of one line each of yarn 21 and yarn 23. The yarn 22 runs zigzag (to left and right) for 3 needle spaces. The yarn 23 runs zigzag for one (1) needle space knotting three (3) microfibers at a time. The yarn 21 runs straight circling each microfiber. Ridges are formed by placing the yarn 21 on every 5th needle and at the back side of the fabric. The yarn 23 also runs the ridged parts and knots microfiber and ridged fibers together. Microfiber loops are longer on the surface than at the back. This is one reason there are ribs or ridges 26 only on the top surface. However, as will be appreciated by those skilled in the art, ridges 26 can also be placed on both the top surface 28 and the bottom surface 36.

FIG. 3 is a hatched diagram and plan view of the fabric 20. FIG. 3 illustrates the same yarns 21-23 of FIG. 2 except the drawing is a hatched diagram rather than a line diagram. In FIG. 2, each yarn 21-23 is illustrated by a single line. In FIG. 3, the yarns 21-23 are each illustrated by a series of hatches.

FIG. 4 illustrates a plan view of the surface of the ridged fabric 20. In FIG. 4, the ridges 26 generally contain the yarn 21 and the areas between the ridges 27 generally contain the yarns 22 and 23. The ridged, microdenier surface 28 of the disclosed knitted fabric 20 is effective at removing viruses, vegetative bacteria, bacterial spores, mold spores and other organic matter. Not only can bacteria be removed, but also high levels of endotoxins can be removed from a wiped surface as well. Endotoxins are the waste from bacteria. This is useful for example in a critically controlled environment in a sterile clean room manufacturing facility, such as a pharmaceutical manufacturing plant, a baby formula facility, a research laboratory or food preparation or compounding plant.

FIG. 5 is a flow diagram of an exemplary method of making the knitted fabric 20. In step 31 a plurality of yarns is formed of different, dissimilar or varying weights. Each yarn is formed in step 32 by spinning a fiber of approximately 1.50 denier or below. In step 33 the fabric 20 is formed by knitting the plurality of yarns of dissimilar (different or varying) weights to have knitted ridges 26 as shown in FIG. 4. Optionally, a refinement of steps 31-34 can be made as shown in FIG. 6. The steps 132-133 usually are performed at the same time as steps 31-33 but can be done separately. Also steps 31 and 32 or 31 and 132 can be performed at the same time. In step 132 the plurality of yarns of different weights is formed by spinning only fibers of the same fabric. In step 133 the fabric is formed by knitting only the yarns of the same material produced above in step 132. The yarns are knitted at imaginary intersection points of a grid, such as the horizontal gridlines 24 and vertical gridlines 25 illustrated in FIG. 2.

A first yarn 22 (FIG. 2) skips the grid and is knitted every other grid. A second yarn 23 (FIG. 2) is knitted every grid. A third yarn 21, the thickest yarn of the three (FIG. 2) is knitted in rows along the grid to form the ridges 26 on a front side 28 (FIG. 4). To achieve the desired properties, the fabric 20 is knitted and not woven. Knitting involves tying knots and weaving uses a warp and a weft. A ridge 26 can be formed in the fabric 20 by yarn that has been knitted around itself.

INDUSTRIAL APPLICABILITY

Exemplary applications for the knit fabric 20 with ridges 26 are mop heads, sponges, applicators for disinfectants, and wipes. The improved fabric 20 transports fluid from one side 28 to an opposite side 35 of the fabric 20, wherein the direction of flow is away from the smooth side 28. The wetter side 35 may include a sponge 36 (FIG. 9), terry cloth or denser microfiber fabric.

Although certain embodiments have been described and illustrated in the above description and drawings, it is understood that this description is by example only, and that numerous changes and modifications can be made by those skilled in the art without departing from the true spirit and scope of this disclosure. Although the examples in the drawings depict only example constructions and embodiments, alternate embodiments are available given the teachings of this disclosure.

Claims

1. A knitted fabric comprising:

a face side comprising a plurality of parallel and elongated ridges,

a back side comprising a surface without elongated ridges.

2. The fabric of claim 1 wherein the fabric comprises a right-leaning top triangle (RTT) stitch.

3. The fabric of claim 1 wherein the fabric comprises yarns spun from filaments made from a material selected from the group consisting of polyesters, polyamides, polyethylene terephthalate and combinations thereof.

4. The fabric of claim 1 wherein the filaments are about 1.5 denier or less.

5. A mop head made from the fabric of claim 1.

6. A cleaning cloth made from the fabric of claim 1.

7. A knitted fabric comprising:

a plurality of yarns spun from filaments of about 1.5 denier or less, the yarns being knitted into the fabric using a right-leaning top triangle (RTT) stitch, the fabric comprising

a first side comprising a plurality of parallel and elongated ridges,

a second side comprising a smooth surface without elongated ridges.

8. The fabric of claim 7 wherein the filaments are made from a material selected from the group consisting of polyesters, polyamides, polyethylene terephthalate and combinations thereof.

9. A mop pad made from the fabric of claim 7.

10. A cleaning cloth made from the fabric of claim 7.

11. A covered sponge comprising:

a sponge, the sponge being enclosed within a knitted cover, the knitted cover being fabricated from a knitted fabric comprising

a first side comprising a plurality of parallel and elongated ridges,

a second side comprising a smooth surface without elongated ridges.

12. The sponge of claim 11 wherein the fabric of the cover comprises a right-leaning top triangle (RTT) stitch.

13. The sponge of claim 11 wherein the fabric of the cover comprises filaments made from a fabric selected from the group consisting of polyesters, polyamides, polyethylene terephthalate and combinations thereof.

14. The sponge of claim 11 wherein the filaments of the cover are about 1.5 denier or less

15. A mop head made from the covered sponge of claim 11.

16. A method of making a knit fabric comprising:

forming a plurality of yarns of dissimilar weights, wherein each yarn is formed by spinning filaments of 1.50 denier or less; and

forming the fabric by knitting the plurality of yarns of dissimilar weights in a right-leaning top triangle (RTT) stitch to have knitted ridges extending in a direction of the knitting and on at least one side of the fabric.

17. The method of claim 16 wherein the forming of the plurality of yarns of dissimilar weights comprises spinning microfiber filaments of different weights.

18. The method of claim 16 wherein the forming of the plurality of yarns of dissimilar weights comprises forming a plurality of yarns of dissimilar weights at least partially from bi-component filaments.

19. The method of claim 16 wherein the forming of the plurality of yarns of dissimilar weights comprises forming a plurality of yarns of dissimilar weights from micro-denier filaments.

20. The method of claim 16 wherein the knitting of the plurality of yarns of dissimilar weights to have knitted ridges further comprises knitting the yarns at imaginary intersection points of a grid such that a first yarn skips the grid and is knitted every other grid, a second yarn is knitted every grid, and a third yarn is knitted in rows along the grid to form the ridges on a front side of the fabric.