US 3641719 A
A cleaning towel comprising multiple paper plies and a cleaning aid adhered to the outer face of a face ply forming one side of the towel. The cleaning aid comprises a granular abrasive material, a detergent, and a binder holding the abrasive material together and adhering the cleaning aid to the paper ply. The cleaning aid is distributed as a noncontinuous coating, forming a pattern of multiple spaced-apart stripes over the face of the paper ply. A back ply provided behind the face ply has a somewhat greater absorbency than the face ply. A method of preparing the towel where the cleaning aid is prepared as a flowable liquid mass and transferred through a striping roll to the face of a continuous paper web. After such coating has dried, another paper web is applied against the back of the web with the coating, to produce an assembly which is then cut into lengths and folded to form the towel. The multiple plies in a towel may be held together with an adhesive, or by mechanical embossing.
Description (OCR text may contain errors)
United States Patent Yang 1 Feb. 15, 1972  CLEANING TOWEL  ABSTRACT  Inventor: Christen H. C. Yang, CamaS, Wa h, A cleaning towel comprising multiple paper plies and a cleanin aid adhered to the outer face of a face I formin one side  Asslgnee" crown Duel-bad Corporahon San Fran of the towel. The cleaning aid comprises a granulaf abrasive c1590 Cahf' material, a detergent, and a binder holding the abrasive [22 Filed; Man 12 19 9 material together and adhering the cleaning aid to the paper ply. The cleaning aid is distributed as a noncontinuous coat- 121 1 p N01 806,532 ing, forming a pattern of multiple spaced-apart stripes over the 1521 Us. c1 ..s1/402 face W A back Pmvided behind the face 511 Int. Cl 824d 11/00 has mmewha 5 absorbemy the A ISM Fleldmsmrch V I I I I I B94407, method of preparing the towel where the cleaning aid is 6 of ml/2s prepared as a flowablc liquid mass and translcrred through a utriping roll to the face ol'a continuous paper web. After such M References Clled coating has dried, another paper web is applied against the back of the web with the coating, to produce an assembly UNITED STATES PATENTS which is then cut into lengths and folded to form the towel. 2,665,528 1/1954 Sternfield et al ..51/402 x The multiple Plies in a towel may be held together with an 3,293,683 12/1966 Wyant ..51/104.93 hesive, mechanical emb0ssing- Primary Examiner0thell M. Simpson Attorney-Kolisch & Hartwell 6 Claims, 2 Drawing Figures CLEANING TOWEL This invention relates to a towel usable in cleaning and drying hard surfaces. The preferred and specific embodiment of the invention disclosed herein comprises a disposable towel made of paper, such as might be employed by service station attendants in the cleaning of automobile windshields, and by housewives in the cleaning of mirrors and windows.
Considering the cleaning of a surface such as a windshield, under the usual driving conditions, an automobile windshield will collect a variety of materials which are difficult to remove using only water and a rag or a conventional paper towel. Cleaning towels have been proposed which have included, as part of the towel, a detergent and/or an abrasive material for the purpose of promoting the towels cleaning action. Such have not been entirely satisfactory for a number of reasons. Thus, some have been too expensive to permit extensive use as a disposable item. Other towels have been difficult to use, in that they are too stiff and do not lend themselves to being wadded up in the hand. With others, it is difficult to use the towel without leaving a residual film or streaks, that impair vision in the case of a windshield. Another disadvantage noted has been what might be described as a lack of proper gliding qualities in the towel over a surface. With towels of multiple plies, an additional problem of ply separation arises. Proper absorbency in a towel is another factor which must be considered.
Thus, a general object of this invention is to provide an improved cleaning towel, usable in washing windshields and like objects, which performs highly satisfactorily and takes care of many ofthe difficulties hereinabove indicated.
Another object is to provide a novel method for the preparation of such a towel.
The towel of this invention features a cleaning aid including a granular abrasive material, where such cleaning aid is distributed as a noncontinuous coating over one side of the towel. In such coating, the granules of abrasive material are adhered together, as well as to the towel, by a water-dispersible binder distributed throughout the cleaning aid. The distribution of the coating is such as to enable the face of the towel to glide over a surface being cleaned, with the surface being contacted by coated as well as uncoated regions, and without the production of what might be thought of as a sandpaper action, which results if the coating is continuous or nearly so. Dirt particles may collect in uncoated regions, and where a detergent is included in the cleaning aid, a foaming and cleansing action with the release of the detergent occurs in such uncoated regions.
in a specific and preferred embodiment ofthe invention, the cleaning aid is distributed as spaced-apart stripes extending over the face of the towel separated by uncoated striped regions, with the width of such stripes of cleaning aid being a minor part of the width of the striped uncoated regions. The towel itself has a thickness which is a minor part of the width of the stripes of cleaning aid. This assures that there is a wide expanse of uncoated region between adjacent stripes containing abrasive material, which may serve to wipe over areas ofa surface being cleaned to remove dirt subjected to a preliminary loosening by the stripes containing abrasive material.
A binder is contemplated for the abrasive particles having a refractive index which is nearly that of glass. With the binder being water dispersible, during cleaning the binder becomes distributed on the surface being cleaned, and most of this is removed with the wiping producing drying. With the refractive index indicated, any binder that may be left on the surface produces no distorting film. A minimal amount of binder may be utilized, since such is not distributed throughout the towel, but instead is concentrated within the cleaning aid, where it functions to hold the abrasive particles together and to the towels face in regions immediately behind the cleaning aid. By having the paper portion of the towel for the most part free of binder, stiffening ofthe towel by the binder is minimized.
A further object of the invention is to provide such a towel featuring a multiple ply construction. A face ply, which has the cleaning aid adhered thereto is used in washing operation.
The face ply is backed up by a back ply used in drying, which like the face ply may be made of paper. The towel may be constructed in such a manner as to inhibit the absorption by the back ply of water coming in contact with the front of the face ply, as by including a water barrier between the plies. This functions to tend to maintain the back ply dry, whereby it may best perform its drying function.
With the cleaning aid distributed in the striped pattern indicated, the towel has sufficient flexibility to permit its being easily crinkled up for washing and drying purposes. This flexibility is also a factor in inhibiting ply separation in a multiple ply towel.
Another feature of one fonn of the invention is the inclusion of adhesive deposits holding the plies of the towel together, where the adhesive is dispersible in aqueous solutions at temperatures under 200 F. to enable repulping of the towel, an important consideration from the manufacurers viewpoint.
These and other objects and advantages will become more fully apparent from the following description, taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a schematic illustration of the process employed to produce the towel; and
FIG. 2 shows portions of a towel as contemplated according to an embodiment of the invention.
Considering first the towel, with consideration then given with respect to how it might be prepared, as illustrated in FIG. 2, the towel comprises what is referred to herein as a towel base 10 formed of two paper plies, shown at 11 and 12. Ply ll constitutes a face or front ply, and ply 12 a back ply in the towel.
The paper in plies l1 and 12 may take the form ofthe usual paper found in hand towels. Such paper frequently is prepared from a kraft-type pulp (or a blended pulp of kraft, sulfite, semichemical and/or groundwood), with a weight of 25 pounds per ream.
When the towel is used to clean a surface, the front ply may be used in a preliminary washing action to loosen dirt, oil, grime, bug deposits, etc., and the back ply may be used in the final drying of the surface. The front ply thus first comes into contact with the wetted surface to be cleaned, and by contacting the surface will absorb some water. This water absorption promotes release of ingredients in a cleaning aid (to be described), and somewhat softens the paper, which is a desired action.
To inhibit wetting of the back ply during the washing step, the towel base may be prepared by including a water barrier between the front and back plies. Such may take the form of a ply or film of nonabsorbent material, such as a sheet of polyethylene, wax paper, etc. Alternatively, the face ply may be coated over its back side with a coating of relatively nonabsorbent material.
Applied over the outer side or face offront ply 11 is a cleaning aid, distributed as a coating. The coating forms a pattern on the face of the ply, more specifically a striped pattern, with stripes 14 of cleaning aid interspersed with noncoated striped regions 16 on the surface of the ply.
A pattern is selected for the coating which permits the retention in the towel of suitable flexibility, whereby it may be readily crumpled up in the hand during the washing process. Further, the towel preferably should have some gliding properties, whereby it can be moved easily over a surface, and a sandpaper type of action is to be avoided. It is important that substantial expanses of uncoated regions in the face of the towel be contactable with the surface being cleaned conjointly with coated regions, as dirt particles are trapped in the uncoated regions and it is in these regions that sudsing of freed detergent takes place.
To attain these ends it has been found that preferably a pattern such as the striped one illustrated be employed, and that the width of the stripes formed by the coating be a minor part of the width of the stripes formed by noncoated regions. Further, the thickness of the towel should be a minor part of the width of the stripes formed by the coated regions. Describing typical toweling, the towel base may have a thickness ranging from 0.008 to 0.02 inch. The stripes of cleaning aid may have a width ranging usually from about 0.03 to 0.20 inch, and the uncoated regions may have a width ranging from 0.125 to 0.5 inch or more. In general, it is preferred that coated areas comprise from to about 40 percent of the total surface area of the towel base.
The cleaning aid comprises, as principal constituents, a granular abrasive material, a detergent, and a binder effective to hold the granular abrasive material together and also to adhere the cleaning aid to the face of ply l 1.
Various coating weights may be employed. The preferred coating weight, dictated by economy and effectiveness of cleaning action, and based on the solids weight of the cleaning aid, ranges from about 0.5 to 6.0 pounds of coating per 3,000 square feet of paper covered. Normally, a thickness in the stripes of coating ranging from about 0.0005 to 0.003 inch might be expected.
In the selection of the abrasive material to be included in the cleaning aid, it is preferred that a material which is water and alkali insoluble be used having a hardness (Moh) ranging from 4.5 to 6.5, and a particle size small enough to pass a 100- mesh screen (149 microns or less). The usual glass found in an automobile windshield has a hardness of about 4.5 to 5.0 (Moh), and by using an abrasive material with the hardness and particle size indicated, scratching of the glass surface is not a problem. With a hardness appreciably below 2.0, scoring power is lost. Since it is difficult in any cleaning operation to remove completely all residue from the surface being cleaned, with the result that some abrasive material may remain on the surface after cleaning, it is preferred that the material selected have a refractive index within the range of 1.4 to 1.7, such being close to the refractive index of glass 1.55).
Exemplifying a preferred abrasive material is pumice, with a refractive index of 1.5. The usual pumice (typically containing about 75 percent silicon dioxide and 12.5 percent aluminum oxide with the remainder being iron oxide, calcium oxide and magnesium oxide) has an oil absorption exceeding 40 (parts per 100 parts pumice) and a hardness of 5.5, and when pumice with the particle size indicated is used, effective cleaning results without scratching of a glass surface.
The proportion of abrasive material included in the cleaning aid will vary depending upon the type of cleansing action desired. in a typical formulation, the cleaning aid comprises from about 30 to about 70 percent abrasive material, on a solids basis. Exemplifying other materials usable as the abrasive are such materials as granular polystyrene, mica, polymethacrylate, and other granular, synthetic and natural high polymers.
As the ingredient binding the particles together, a binder is selected which is water dispersible. Such term, as used herein, includes materials that are either dissolved, or broken up by water. Furthermore, the binder should have a refractive index within the range above indicated, i.e., 1.4 to 1.7, in order that any residual of the binder which remains on a surface not produce a distorting film on the windshield. Various materials are usable as a binder, including hydroxyethyl cellulose, polyvinyl alcohol, carboxymethyl cellulose, etc. A preferred ingredient is the so-called common water glass, such being readily available, being water soluble, and having a refractive index which is essentially the same as that of glass. The binder ordinarily comprises from 10 to 70 percent of the coating, on a solids basis.
A detergent is also included in the cleaning aid, to facilitate the loosening and removal of dirt including grease, etc. With water glass used as the binder, and such being quite alkaline, it is important that the detergent be stable at pH's ranging from about 10 to 12. Most anionic and nonionic detergents can be used, but cationic detergents will not work in such a system. Exemplary of a detergent that is employable is the sodium salt of a sulfated alkylphenoxypoly (ethyleneoxy) ethanol. The detergent ordinarily comprises from about 2 to percent of the coating, on a solids basis.
With the cleaning towel prepared as contemplated, there is some stiffening of the face ply 11 forming the face of the towel, but not such as to prevent the same from being easily wadded up for washing and cleaning purposes. The flexibility of the face ply is also sufficient to permit the two plies of the usual double-ply towel to hold together during handling, especially if a dispensing tray is used in dispensing the towels. However, if it is desired to anchor the plies together more firmly, the invention contemplates providing an adhesive deposit between the plies of the towel, with such serving to tack the plies together. For this purpose, an adhesive is contemplated which is dispersible in aqueous solutions at temperatures below 200 F. and having a pH ranging from about 4 to 12, to permit the towel product to be repulpable. Exemplary of such adhesive is a wax blend which melts at 200 F., such being easily dispersed in the hot water system which usually characterizes a repulping machine. In the manufacture of 9 to 10 inch square toweling, a thin ribbon of such an adhesive extending between opposite margins of the towel was found to hold the plies together under all but the most unusual conditrons.
It will be noted that according to the invention, a binder is utilized which is distributed throughout the cleaning aid. Thus, the binder functions to hold all the particles in the cleaning aid together, as well as to hold the cleaning aid against the face of ply l1. Ply 11 itself contains no binder, save for those regions of the paper ply which are immediately behind the coating of cleaning aid, which may absorb some binder during the process of applying the cleaning aid. This simplifies the manufacture of the paper ply, and minimizes the amount of binder needed to make a towel. Further, there is no stiffening of the towel in uncoated regions. At the same time, the granular abrasive material is most effectively bonded in place. With the binder included as part of the cleaning aid, and with the binder water dispersible, it is possible to make an aqueous mixture of binder, abrasive material and detergent, which is liquid in form and flowable, and apply the cleaning aid by rolling the same onto. the surface of ply 1 l.
Explaining how the cleaning towel may be manufactured, and reference is now made to FIG. 1, illustrated in somewhat simplified form is equipment for applying a coating to the face of a continuous paper web, shown at 20. The paper web is contained on a roll 22, and extends from this roll over a guide roll 24, a backup roll 26, and another guide roll 28.
A three-roll printing unit is designated generally at 30. Such includes a rubber-surfaced fountain roll 32, a so-called Anilox roll 34, and a rubber-surfaced printing or striping roll 36.
Further describing the printing unit, the Anilox roll is a chrome-coated roll with four-sided frustopyramidal recesses prepared therein. The recesses are quite small and relatively closely spaced, and they function to retain an amount of coating material when they are moved past a supply thereof. Roll 32 is usually rotated at a somewhat slower speed than the Anilox roll, and a supply of coating material is fed to the nip between the two rolls, as shown at 38. In this way, roll 32 acts to wipe excess off the Anilox roll.
Printing roll 36 has a series of ridges prepared thereon separated by grooves. When the printing roll rotates against the Anilox roll, there is a transfer of coating material from the Anilox roll to the printing roll, but the transfer occurs only in the region of the ridges which are the only regions that contact the Anilox roll.
Also included as part of the apparatus are a pair of infrared heaters, shown at 40, 42. These are disposed on opposite sides of the web, and are effective to dry the web and its coating after the web passes the printing roll.
A paper roll 48 contains windings of a paper web 50 which pass from the roll and around a guide roll 52 thence to be directed against the back side of web 20. In this way, an assembly comprising two plies of paper, with one ply having a noncontinuous coating applied to its face, is prepared. In producing toweis, this two ply assembly is cut and folded, using conventional techniques.
Describing the preparation of a paper towel, a coating composition was prepared in a I65-gallon tank equipped with a Cowles dissolver from the following: water glass, 280 parts; pumice, 120 parts; detergent, 25 parts (a sodium salt of sulfated alkylphenoxypoly (ethyleneoxy) ethanol, available commercially as Alipal 150526;); dye (ultramarine blue), 2.5 parts; water (vehicle), 23 parts.
The water glass used was an aqueous solution of sodium silicate, (thus containing water as a vehicle) and had the following specifications: sodium monoxide, 8.86 percent; silicon dioxide, 28.35 percent; Baume (68 F.), 41 percent; viscosity (68 F.), 1.8 poises; pH, 11.
The pumice employed had a particle size permitting it to pass through a 200-mesh Tyler screen, and contained about 75 percent silicon monoxide and 12.5 percent aluminum oxide. The pumice had an oil absorption of53.
The above coating composition, which had a syrupy consistency, was fed to the nip defined between an Anilox roll and a fountain roll, in equipment of the type illustrated in FIG. 1. An Anilox roll was utilized having recesses of about 0.02 inch depth, distributed at the rate of 100 per lineal inch over the roll surface. A rubber print or striping roll was utilized to transfer the composition to a web 11 of paper toweling of about 47.5 inch width and 0.006 inch thickness,-producing stripes on such web of about three thirty-seconds inch width, separated by uncoated areas of five thirty-seconds inch width. The coating composition was spread at the rate of 3 pounds per ream.
Another web of paper toweling was directed against the back side of the web with coating applied. Towels were prepared from the two-ply assembly so produced by cutting the two-ply assembly into strips a little over 9 inches in width and these strips into lengths slightly exceeding 9 inches, and by folding these cut lengths.
Towels prepared as indicated were used in service stations for cleaning road grime and dirt from Windshields. ln cleaning, the side of the towel with the cleaning aid was first moved back and forth across the windshield, after wetting the windshield to loosen dirt and road grime and produce a preliminary cleaning. Final cleaning was performed by wiping the windshield with the back ply in the towel. The towels bunched up readily in the hand, and moved easily over a windshields surface without scratching. The stripes of abrasive material remained in place throughout the service life of the towel. Final wiping with the back of the towel produced Windshields free of any smears or distorting films.
Towels were also prepared with an adhesive (wax) deposit tacking the plies together. These performed equally as well,
and were somewhat easier to handle in that they could be picked up one at a time from a pile without ply separation occurring.
While embodiments of the invention have been described it should be obvious that variations and modifications are possible without departing from the invention.
It is claimed and desired to secure by Letters Patent:
1. A cleaning towel comprising a paper face ply, a discontinuous coating containing granular abrasive material extending over the outer surface of said face ply and forming a pattern on said surface with areas of such pattern interspersed with noncoated regions on said surface, said coating further including a water-dispersible solid binder for the abrasive material which is the dried residue of water glass, said binder being distributed throughout the coating and having a refractive index within the range of about 1.40 to 1.70, said binder by being distributed throughout the coating being effective to hold the granules of the abrasive material cemented to each other as well as to the face ply over which the coating extends.
2. The towel of claim 1 which further comprises another paper ply backing up the face ply.
3. The towel of claim 1 which further comprises another ply of absorbent paper backing up the face ply, and wherein said other and face ply are joined by an adhesive, said adhesive being dispersible in an aqueous solution at temperatures below 200 F. and havinga plH ranging between 4 and 12.
4. The towel of claim w ich further comprises a detergent distributed in said coating together with the abrasive material and binder.
5. The towel of claim 1, wherein said discontinuous coating forms a pattern of multiple stripes over said surface, with such stripes interspersed with stripes formed of noncoated regions, the widths of the stripes formed by the coating being a minor part of the width of the stripes formed by the noncoated regions, and the thickness of the towel being a minor part of the width of the stripes formed by the coated regions.
6. A paper cleaning towel comprising a cleaning aid comprising a mixture of granular abrasive material, detergent, and a solid binder distributed throughout the cleaning aid effective to hold the mixture together, said binder being the dried residue of water glass; a towel base comprising face and back plies of absorbent paper; said cleaning aid forming a discontinuous coating over the face ply; said coating being adhered to said face ply by said binder in the cleaning aid; the coating forming a pattern over said towel base with areas of said pattern interspersed with noncoated regions of the towel base; said face ply being essentially free of cleaning aid material save in regions that immediately back up the coating.