US 2713361 A
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nited ABSGREEPJT DRZlN-G eroras zirpplication ()ctober 23, @552, Serial No. 316,526
3 (Ilaims. (Cl. 139-425) This invention relates to soft, flexible water-absorbing Woven cloths, so-called drying cloths, more particularly dish towels, hand towels, chamois substitutes, and the like. The performance and utility of such drying cloths are dependent on a combination of properties, of which the two most critical are the facility with which the cloth absorbs water and the amount of water which it can hold while still efficiently performing its drying function. Other important considerations are durability and freedom from linting in performance.
The most serious objection to dish towels hitherto available is their rapid decrease in wiping efiiciency after appreciable amount of water is picked up from the surface which is being wiped. Every householder is familiar with the unsightly smears and streaks produced when an attempt is made to dry dishes, glasses, or silverware with a cotton or linen dish towel which is damp to the touch. The ordinary drying cloth is similarly unsatisfactory in the removal of water from the surface of an automobile after it has been washed, because the cloth rapidly becomes useless for wiping purposes as it sops up the water. It merely redistributes the surface water in the form of droplets or streaks, and no amount of hand wringing sufiices to restore the original wiping efficiency of the cloth.
It is an object of this invention to provide a wash able, durable, absorbent drying cloth which will remove water from surfaces easily, thoroughly, and substantially without linting, and maintain its high wiping efiiciency despite appreciable pickup of moisture.
it is the special object of this invention to provide a wiping cloth for use as a chamois substitute which will perform efficiently at a suiiiciently high moisture pickup level so that when this level is exceeded, hand wringing will restore performance.
We have discovered that a drying cloth woven of yarns consisting essentially of spun fibers of regenerated celluose of 1 /2 denier or finer is markedly superior in performance to the prior art wiping cloths and dish towels. In their preferred constructions, the drying cloths of this invention surpass even genuine chamois in performance.
The high capillarity of the drying cloths of our invention in comparison with various prior art products is shown below in Table l. One-inch strips of each of the cloths tested were conditioned for 4 hours at 65% relative humidity and 21 C.; then the strips were hung vertically with one end of each immersed in colored water. The capillary rise over a -minute period was measured.
tates Patent 0 2,713,3hl Patented July 19, 1955 "ice 1 Geometric mean of warp and filling measurements.
This table provides a relative index of the thirstiness or speed of absorbency of the various drying cloths and provides a reliable measure of their initial performance. As previously noted, however, initial performance is but one of the features of our novel fabric. Equally important is the amount of water which the cloth can pick up before it ceases to wipe in a satisfactory manner. With respect to this property, the comparative performance of drying cloths composed of various materials is graphically illustrated by the curves of Figure l in which the degree of smearing is plotted against the moisture content of the drying cloth in per cent water based on the dry weight of the cloth. The compositions of the cloths associated with each of these curves are listed in the following table:
The data from which these curves Were plotted, were obtained by testing each of the drying cloths at various moisture levels as to its ability to wipe a clean, polished glass surface without smearing. Performance was rated 0, 1, 2, and 3 according to the relative amount of streakiug or smearing produced, the 0 value corresponding to a condition of the wiping surface in which there was no trace of a smear. After each cloth had been tested at any given moisture level, it was centrifuged to remove a portion of the contained water weighed, and retested. This process was repeated until each of the Wiping cloths had reached a moisture level at which no trace of a smear was produced on the wiped surface.
The no-trace, or cut-off moisture content of the various drying cloths tested is significant because it serves as a reliable index of the useful wiping range of the cloths. Also in evaluating the probability of error in the experimental results it is obvious that the determination of the presence or absence of a streak or smear is less subject to observational error than discrimination between and among various degrees of smearing. However, the points plotted in each curve for the 1, 2, 3 values of smearing are undoubtedly in the correct relative order and serve to emphasize the common tendency of all of the drying cloths tested to decline rapidly in wiping efficiency after the cut-elf level of contained moisture is exceeded. The relatively steep slope of each of the curves further substantiates the accuracy of the cut-off point determination because of the small increment in moisture content between the O and 1 values of smearing.
It should be thoroughly understood that the absolute values of the cut-off moisture contents for the various drying cloths will vary with the ambient temperature, humidity, and air velocity but the relative values will remain substantially unchanged.
Preferably the drying cloths of our invention are woven with a high proportion of fioats. That is, for a given yarn size and count, it is desirable that the frequency of interlacing of the warp and filling yarns be relatively low. A number of suitable weaves are shown in Figures 28 of the drawings. In each of these diagrams, the rows of squares along the length of the page represent warp yarns, and the rows of squares across the page filling yarns. An indicates that the warp yarn is up and the filling yarn down; a blank space indicates the reverse position. The length and breadth of the diagram shows the number of warp and filling yarns necessary to produce a repeat of the pattern. For each of these constructions, we have computed an interlacing frequency factor based on the total number of interiacings of warp and filling yarns relative to the total number of squares in the repeat. An interlacing is defined as a change in direction of a yarn as it goes from one face of the fabric to the other. For example, in the weave pattern shown in Figure 2, there are 2 changes in direction in each of the eight warp yarns, and 4 changes in direction in each of the filling yarns. Since there are 32 squares in the repeat, the interlacing factor is (16|16)+32 or 1.0.
For optimum performance with respect to capillarity and useful moisture capacity, we prefer weaves in which the interlacing frequency factor, as herein defined, is not greater than 1.5. An additional advantage of such constructions is that despite repeated launderings and the progressive shrinkage resulting therefrom the drying cloths do not stiffen and develop a harsh hand as they pick up water but retain their original softness and flexibility.
Drying cloths having relatively few interlacings are especially adapted for use as a chamois substitute because when they have picked up too much water to continue to wipe efficiently, hand-wringing sulfices to reduce their water content substantially below the smear or cut-off point and to restore their original performance.
Because of considerations of durability, especially susceptibility to the formation of holes in use, it is preferable to avoid drying cloth constructions in which the interlacing frequency factor is less than 0.60, although such constructions may be perfectly satisfactory in other respects.
Preferably, the various commercial products of this invention consist of fabrics having yarn counts which vary from as low as 32 x 30 to as high as 148 x 64, with the yarns ranging in size from 6s to 40s, the coarser yarns naturally being employed with the lower counts, and the cloth cover factor, or the proportion of the area covered preferably being at least 0.70. Cloth cover factor is determined in accordance with the formula set forth by F. T. Pierce in The geometry of cloth structure, Journal of the Textile Institute, March 1937, page T52.
From the viewpoint of wiping performance alone, the best results are obtained when the drying cloths of this invention consist entirely of regenerated cellulose fibers of 1 /2 denier or finer in size, the term regenerated cellulose being intended to include both viscose and cuprammonium rayon. However regenerated cellulose fibers coarser than 1% denier and other natural and synthetic fibers may be incorporated in the product in minor amounts, either as yarns or yarn constituents, without departing from the spirit of our invention. For example,
the wet strength and durability of our drying cloths may be improved by employing yarns in which up to 50% cotton fibers are blended with the fine rayon fibers. Any increase in the proportion of cotton fibers beyond 50% is undesirable as the cloth then begins to assume the performance characteristics of a cotton product and any gain in wet strength is offset by the loss in moisture capacity as compared with a cloth composed entirely of fine rayon fibers. If the blend is to contain instead of cotton a secondary fiber of less absorbency, correspondingiy srnailer proportions of the secondary fiber should be employed.
in the manufacture of dishtowels, it is frequently the practice to apply a final size after the usual finishing operations in order to give the dishtowels a firmer, crisper hand and enhance their appearance and sales appeal. We prefer to omit this final size in the finishing of our dry tg cloths because it temporarily detracts from the wipmg performance by reducing the absorbency of the towel. However, such sizes may optionally be used because they are substantially removed by the first laundering, and housewives are generally familiar with the fact that a dishtowel may have to be washed before it will perform satisfactorily.
in actual tests of our drying cloths as dishtowels, an overwhelming majority of the testers expressed a strong preference for the towels of this invention over a wide variety of conventional dishtowels, including ones of 100% linen, cotton, and various fiber blends. This preference was indicated not only for overall performance but also with respect to each of the important individual properties, absorbency, useful capacity, and freedom from linting.
Because of the remarkable combination of desirable properties which our cloths possess, they have found application in a variety of household uses in addition to the wiping of dishes. They are particularly efiicient in removing surface water from windows and automobiles without leaving streaks or smears behind. Their soft supple hand ideally suits them for use as babies towels.
As illustrative of suitable constructions for our drying cloths the following examples are given. The interlacing frequency factors were computed in the manner previously described.
Example 1 Fibers: l /z-dcnier, regular tenacity, dull viscose rayon Yarns: Warp23's, filling2ls (cotton system) Count: 112 x 56 Weave: As shown in Figure 2 interlacing frequency factor: l.0
Example 2 Fibers: 70% l /z-denier, regular tenacity, dull viscose rayon, 30% cotton Yarns: Warp-23s, filling2ls Count: 112 X 56 Weave: As shown in Figure 2 interlacing frequency factor: 1.0
Example 3 Fibers: l /z-dcnier, regular tenacity, dull viscose rayon Yarns: Warp-3s, filling-2T5 Count: 112 x 56 Weave: As shown in Figure 3 interlacing frequency factor: 1.13
Example 4 Fibers: l /z-denier, regular tenacity, dull viscose rayon Yarns: Warp23s, filling-Zls Count: 112 X 56 Weave: As shown in Figure 4 interlacing frequency factor: 1.0
Example 5 Fibers: ll-denier, regular tenacity, Yarns: Warp-23's, filling-21s Count: 112 x 56 Weave: As shown in Figure 5 Interlacing frequency factor: 0.667
dull viscose rayon Example 6 Fibers: l /z-denier, regular tenacity, Yarns: Warp23s, filling-2ls Count: 112 x 56 Weave: As shown in Figure 6 Interlacing frequency factor: 0.8
dull viscose rayon Example 7 Fibers: l /z-denier, regular tenacity, Yarns: Warp 23s, filling--21s Count: 112 x 56 Weave: As shown in Figure 7 Interlacing frequency factor: 1.25
dull viscose rayon Example 8 Fibers: Ila-denier, regular tenacity, Yarns: Warp-23s, filling-21s Count: 112 x 56 Weave: As shown in Figure 8 Interlacing frequency factor: 1.25
dull viscose rayon sorbent cellulose fibers and mainly of staple fibers of regenerated cellulose, said regenerated cellulose fibers being not greater than 1% denier.
2. As an article of manufacture, a soft, flexible absorbent drying cloth having substantial drying capacity while holding more than 75 water, based on the dry weight of the cloth, comprising a weave of yarns consisting of absorbent cellulose fibers and mainly of staple fibers of regenerated cellulose not greater than 1% denier in size, said yarns being not coarser than 6s, and not finer than s, said cloth being further characterized in that the Warp yarns and filling yarns have an interlacing frequency factor, as herein defined, of not more than 1.5 and not less than .6.
3. As an article of manufacture, a soft, flexible, absorbent drying fabric having substantial drying capacity while holding more than water, based on the dry Weight of the cloth, consisting of a weave of warp yarns and filling yarns having an interlacing frequency factor of between .6 and 1.25, said yarns consisting of absorbent cellulose fibers and mainly of staple fibers of regenerated cellulose, said regenerated cellulose fibers being not greater than 1% denier.
References Cited in the file of this patent UNITED STATES PATENTS McCormick May 2, 1934 Coulter June 28, 1938 Crawley Oct. 28, 1952 OTHER REFERENCES