US 3144671 A
Description (OCR text may contain errors)
1964 A. s. GOULD ETAL 3,144,671
' DUST CLOTH Filed April 4, 1958 F fg. 3
ARTHUR S. GOULD 8| BY PHILIP NATHANSON United States Patent 3,144,671 DUST CLOTH Arthur S. Gould, @ld Greenwich, Conn, and Hailip Nathanson, Brooklyn, N.Y., assignors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware Filed Apr. 4, 1958, Ser. No. 726,578 3 Qlaims. (Ql. 15-15) This invention relates to improved dust cloths and more particularly to improved lint-less dust cloths which retain their superior dust-collecting qualities even after repeated laundering.
Heretofore, various fabrics, papers and other articles have been employed as dust cloths. Although these materials, when clean, collect dust satisfactorily for a short period, relatively small amounts of dirt clog the pores of the material and continued use merely spreads the dust without retaining any additional dust in the dust cloth itself. These dust cloths then either must be discarded or laundered to remove the dust.
Numerous attempts have been made to improve the dust-collecting properties and reduce the lint of dust cloths. For example, the cloths have been subjected to various chemical treatments. Although these chemically treated cloths collect dust very well when new and are then relatively lint-free, washing the cloths when they become clogged with dust at least gradually removes the chemical coating thereon until its effectiveness is completely negligible. Oil treatment is another common expedient for improving dust cloths, but such treatment is at best a temporary expedient, so far as dustcollecting properties are concerned; the oil employed is preferably a drying oil, such as a furniture polish, so that the oil film dries to a harder polish film and does not leave an undesirable scum; unless the conventional cloth is cleaned frequently or unless only clean portions are used and oiled frequently, the oil itself becomes dirty and its effect is to produce an undesirable soiled scum.
In view of the above difficulties, it was surprising to discover that the dust cloths of the present invention overcome the difiiculties encountered in the use of conventional treated and untreated dust cloths. For example, the dust cloths of the invention not only possess superior dust-collecting properties without any chemical treatment but retain these properties until they eventually wear out. The dust cloths of the present invention, though tough and durable, will not scratch even the most highly polished surfaces. Laundering, rather than diminishing the dust-collecting property, restores it when,
through use, the cloth becomes loaded with dust and soil. Due to the relatively greater dust-holding capacity of dust cloths made according to this invention, as compared with cloths of the prior art, laundering is less frequently required. Because of the scratch free properties of cloths made according to this invention, they often appear to polish without polishing oils where polishing oils would often be used with other cloths. When polishing oils, wax emulsions, etc., are used, due to the relatively greater capacity of these cloths, application of polishing material seems to be less frequently required and the polishing film appears to be cleaner and, thus, brighter. Furthermore, these dust cloths can be returned to service in a matter of minutes after laundering. Also, the dust cloths of the invention are simple in construction and relatively inexpensive to manufacture.
Other and further objects and advantages of this invention will be apparent from the following specification, claims, and drawings, in which:
FIG. 1 is a plan View of a dust cloth made according to this invention.
3,144,671 Patented Aug. 18, 1964 "Ice FIG. 2 is an enlarged diagrammatic section taken along the lines 2-2 of the preferred embodiment shown in FIG. 1.
FIG. 3 is a diagrammatic detail taken along the plane 3-3 of FIG. 2.
FIG. 4 is an enlarged diagrammatic detail similar to FIG. 2 but showing a modification of a dust cloth according to this invention.
The dust cloths of the present invention comprise an inner layer 20 of an absorbent material such as a sponge, a woven or unwoven fabric, etc., between outer layers 10 of fabric woven from flat thermoplastic polymeric yarns 1. Suitable thermoplastic polymeric materials are those possessing the tribo-electrostatic characteristic such as, for example, polyethylene terephthalate, polyethylene and like polyolefines, nylon, saran, polystyrene and the like. This tribo-electrostatic characteristic is the ability of a material to create an electrostatic charge by frictional movement in contact with a surface of another material. Such tribo-electrostatic materials characteristically have high dielectric strength.
The tribo-electrostatic yarns employed in weaving cloths suitable for the outer layers 10 are preferably flat mono-filament yarns, as contrasted with fibrous spun yarns or even round mono-filament yarns of the same material. They may be extruded in their flat shape but preferably they are formed by the fine slitting of a film of the desired plastic, giving the resultant yarn a rectangular crosssection. Various widths and thicknesses may be employed, depending upon the inherent flexibility and strength of the material. For example, if the tribo-electrostatic material is the preferred polyethylene terephthalate, the thickness of the flat yarns generally ranges from about 1.5 mils to .5 mil, thicker yarns becoming too stiff to provide the desired flexible textile and thinner yarns being essentially to weak to withstand substantial wear (as well as being diflicult to produce in commercial quantities at the present time); the average thickness of 1 mil has been found particularly suitable. The width of the flat yarns appears less critical, yarns narrower than one-hundredth or one hundred twenty-fourth of an inch being both weak and difficult to slit and spool. For the desirable planar distortion of the textile without requiring weaves that are too loose, yarns of about of an inch width have been found most satisfactory although widths as coarse as of an inch and possibly even wider may be employed.
The textiles for the outer layer of the fabric are preferably woven from the flat yarns 1 without twisting so that the flat, wider surface of the yarn is presented, as shown in FIG. 2. To present the flat surface area of the yarn so that less of the yarn surface is curved as it serves as the warp or weft of the textile, at least a 2 x 2 twill or a basket weave is employed when both the warp and weft are of the desired tribo-electrostatic yarn although, of course, 1 x 1 square weaves may be employed as well as weaves in which the tribo-electrostatic yarns comprise only the warp or weft and conventional spun yarns are employed in the other direction. In such latter embodiments, either loom tensions and/or yarn spacings are adjusted to cause the tribe-electrostatic yarns to be a substantial portion of the surface of the textile.
Due to the desirable weaves, the preferable fabrics for the outer cover must be relatively loosely woven to prevent the fiat yarns from cutting into each other as the fabric is distorted in use. Due to the slickness and fiatness of the yarns, they slip over each other easily and the looseness of the weave, in so far as yarn spacing or count is concerned, is thereby augmented. Accordingly, it is desirable to incorporate in the textile 10 spaced warps and fills of conventional spun yarns to provide a network of locking spun yarns 2, the heddles for the locking warps 2 and for all warps when the shuttles for the locking fills 2 are thrown being set so that each yarn 1 is interwoven with the yarns 2. The yarns 2 not only tighten the weave somewhat but, because the yarns 1 are usually relatively elastic, the network of yarns 2 also limits the stretch of the fabric along or across the straight of the goods.
The fabric alone possesses excellent dust-collecting properties and pieces may be used as a dust cloth in single thicknesses or in several thicknesses quilted or woven together. Except for mechanical entrapment in the weave, the fabric 10, due to the flat mono-filament yarn 1, possesses even less absorption properties and volume than if it were woven of round mono-filament yarns. Apparently due to the flat surface of the yarns 1 being presented to the surface to be rubbed, the fabric 10 seems to acquire high electrostatic charges which pick up and hold dust regardless of temperature and either atmospheric moisture or moisture film that may be ad hered to the yarn. Because the absorptive capacity of a dust cloth is limited, particularly for polishing or cleaning liquids, it was thought that the absorptive capacity of a dust cloth comprised of the fabric 10 for such liquids could be increased (as it was) by sandwiching an absorptive layer between outer plies of the fabric 10. By chance a thin sheet of open-celled flexible urethane sponge was selected as a filler 20. Not only was the absorptive capacity of the cloth for liquids increased, as expected, but even when dry the absorptive capacity of the cloth for dry dust was greatly increased. Apparently during rubbing dry dust is worked through the interstices of the fabric 10 where it is picked up and held in the voids of the sponge filler 20. Sheeted synthetic flexible sponge approximately 7 16 inch thick seems to be about optimum thickness. Thicker sponges may be employed but are inclined to make the dust cloth unnecessarily thick without a proportionate increase in dust-collecting capacity. Why the tribo-electrostatic properties of the fabric 10 should operate to pick up dust but permit the apparent release of the dust to the inner sponge 20 is not understood. Similar transfer results are obtained with fillers 20 of woven and unwoven cloth, thin batts of absorptive fibers, felts, and the like. The effectiveness of the dust cloths for carrying polishing liquids also exceeded expectations, the interstices of the relatively non-absorptive fabric 10 apparently function to meter the liquid carried in the filler 20 as a reservoir so that a suitable amount is left as a polishing film.
To prevent the filler 20 from lumping within the outer layers of fabric 10, the several layers are preferably quilted with stitches 21. The edges of the dust cloths are suitably hemmed or stitched by the stitching 22, as shown in FIG. 1. The dust cloths of the present invention can be of any desired size or shape although sizes and shapes similar to conventional dust cloths are preferred. A square dust cloth of a size slightly more than one foot on each side has been found to be particularly successful. Other successful embodiments have employed the dust cloth in the form of a mitt or have employed a mitt stitched on the back of a piece of the dust cloth construction as shown in FIG. 2.
It is not to be understood that when the fabric 10 is used in combination with an absorptive filler 20 that the dust cloths need to be sandwiched between two layers of the fabric 10. Instead, to prevent the soil picked up in the filler from transferring showing through to the side of the cloth handled by the user, the dust cloth construction may comprise a ply of fabric 10, an absorptive filler 20, and :1 ply of conventional fabric suitably sized or coated to render it relatively impermeable and/ or opaque to soil, as shown in FIG. 4. This modified form of the dust cloth is particularly useful for sew- 4- ing into mitts, the relatively impermeable ply 30 serving as the lining for the mitt.
Simple washing in a suitable detergent and suitable rinsing serves to restore the dust cloths of this invention to their original condition when the cloths become overloaded with soil. Although the yarns are non-abrasive, it is suspected that the square edges of the slit film yarns, when woven in the desired fashion, aid in the removal of undesirable scum and thus exert some polishing or cleansing action.
The fabric 16 presents a glossy, almost cellophane-like appearance. While it is manifestly desirably lint-free, it is most surprising that it also picks up and holds very substantial quantities of dust, a property which would seem to be very inconsistent with the glossy, film-like surface of the fabric, regardless of its tribo-electrostatic characteristic. It is not known whether this dust-collecting capacity is due to the tribe-electrostatic characteristic of the yarn 1, the edges of the flat yarns (which impart a somewhat raspy feel or hand to the fabric 10), or a combination of these and/ or other presently unappreciated characteristics. Although the dust-collecting mechanism of the particular dust cloth construction of the present invention is not definitely known, it is apparent from the foregoing description of the invention that various modifications can be made within the scope of the invention. Therefore, the scope of the invention is to be limited only by the following claims.
What is claimed is:
l. A fabric for dust cloths and the like in which a substantially major portion of the fabric surface is comprised of fiat, substantially untwisted mono-filament nonfibrous yarns consisting of a tribe-electrostatic plastic, non-fibrous film of polyethylene terephthalate of a thickness ranging between 1.5 and .5 mil and slit to a substantially rectangular cross-section having relatively sharp edges and a width ranging between one one hundred twenty-fourth and one thirty-second of an inch, said fabric being woven so as to present the width, rather than the thickness of the yarn to the surface of the fabric.
2. A dust cloth comprised of (a) an outer layer of fabric in which a substantially major portion of the fabric surface is comprised of flat, substantially untwisted mono-filament nonfibrous yarns consisting of a tribo-electrostatic plastic, non-fibrous film slit to a substantially rectangular cross-section having relatively sharp edges and having a cross-section of greater width than thickness, said fabric being woven so as to present the width, rather than the thickness of the yarn to the surface of the fabric,
(12) a relatively impermeable layer,
(0) a relatively absorptive intermediate filler layer included between said outer layer and said relatively impermeable layer, and
(d) stitching quilting said layers together.
3. A dust cloth comprised of (a) an outer layer of fabric in which a substantially major portion of the fabric surface is comprised of flat, substantially untwisted mono-filament nonfibrous yarns consisting of a tribo-electrostatic plastic, non-fibrous film slit to a substantially rectangular cross-section having relatively sharp edges and having a cross-section of greater width than thickness, said fabric being woven so as to present the width, rather than the thickness of the yarn to the surface of the fabric,
(1)) a relatively absorptive intermediate filler layer comprising a sheet of expanded synthetic plastic sponge having inter-connected cells, and
(c) stitching quilting said layers together.
(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Peple Nov. 1, 1870 Hagedorn et a1 Mar. 23, 1937 Hyman Jan. 25, 1938 Glaskowsky Mar. 26, 1940 Stedman July 25, 1944 Fox Feb. 21, 1950 Cameron July 1, 1952 6 Simon et a1. Jan. 12, 1954 Thomas Apr. 3, 1956 Politzer et a1. Sept. 3 1957 Elliott May 12, 1959 Reiter June 23, 1959 Corrington Nov. 3, 1959 FOREIGN PATENTS France Feb. 17, 1954