US 3597299 A
Description (OCR text may contain errors)
Aug. 3, 1971 G, D, THOMAS EI'AL 3,597,299
. DISPOSABLE WASHCLOTH Filed July 5, 1968 3 Sheets-Sheet 1 Aug. 3, 1971 Filed July 3, 1968 G. D. THOMAS ETAI- DIsPoSALE wAsHcLoTH SCRIIVIA COAT SCRIM WITH THERMOPLASTIC ADHESIVE APPLY CREPED TISSUE TO EACH SIDE OF SCRIM HOT MICROCREPE THE DRY COMPOSITE EMBOSS THE MICROCREPED v COMPOSITE (OPTIONAL) FIG. 6
I5 Sheets-Shoot 2 Allg. 3, 1971 G, D, THQMAS E TAL 3,597,299
DISPOSABLE wAsHcLo'I'H Filed July 3. 1968 3 Sheets-Sheet 8 I5 COTTON FIBERS I6* POLYPROPYLENE 3,597,299 DISPOSABLE WASHCLOTH Gordon D. Thomas and `lerome L. Schwoerer, Neenah, Wis., assignors to Kimberly-Clark Corporation, Neenah, Wis.
Filed July 3, 1968, Ser. No. 742,306 Int. Cl. B32!) 23/ 02 U.S. Cl. 161--57 7 Claims ABSTRACT F THE DESCILOSURE A disposable washcloth having utility as a facecloth and characterized by a plurality of desirable physical properties for body washing including a degree of surface roughness. The roughness is occasioned by a structure which includes a scrim having creped threads bonded over their length between and to creped cellulose wadding layers; the creped threads of the scrim carry a thermoplastic adhesive and in the product such adhesive is present to some extent in the wadding layers 'as relatively rigid nuggets, protuberances or the like aiding in crepe retention and imparting to the outer cellulose layers the rugosity or roughness desired. The process of formation includes hot, and preferably dry, creping the composite of cellulose layers and 'adhesively treated scrim to provide a fine crepe in the product as a whole. This crepe is retained by the set thermoplastic adhesive at temperatures common to washcloth use.
BACKGROUND OF THE INVENTION Field of the invention This invention relates to disposable washcloths and is particularly concerned with products of a nature capable of serving as facecloths by virtue of their dominant physical characteristics, that is, a definite rugosity in the wet and dry state accompanied by a surface texture, bulk, drape and non-linting abrasive resistance. The invention also is directed to a method of forming such washcloth.
The invention with relation to the prior art Disposable washcloths for washing of the human body and including disposable facecloths are known. Such products, while disposable, are commonly re-usable to a limited extent and the term disposable applies in this sense and in the sense that the product is relatively inexpensive.
Prior art disposable washcloths have included structures of reinforced cellulosic wadding sheets. These known disposable washcloths, though serving a useful purpose, have disadvantages which limit their acceptance; particularly the cellulose wadding or cellulose tissue sheets have a dry, somewhat hard, harsh feel when dry and, wetted for use, exhibit a slippery feel as well as having a tendency to ball-up during use.
The present invention is directed to the overcoming of these undesirable properties of the prior art products by providing a structure which has a developed roughness or rugosity which is retained in the wet state and which product has a built-in resiliency.
The somewhat rough and desirably textured surface is achieved by a combination of 'adhesive disposed on threads of the scrim and creped cellulose wadding sheets bounding the scrim, the combination or composite being provided as a whole with a iine creped structure. This creped structure is well retained even when the product is highly wetted. The crepe structure permits limited scrirn extension with the crepe cellulosic wadding, thus providing for toughness, foldability, crumple resistance, resiliency and the like in both the wet and dry condition of the washcloth. Also, the crepe at the 'adhesive zones is retained by nted 'States Patent the adhesive and accentuates the protrusion of the overlying wadding in the adhesive zones.
In the process of invention the scrim carries a thermoplastic adhesive which bonds the cross-threads together and to the wadding. In the preferred embodiment of the process the layered composite of scrim and creped wadding plies is hot calendered to provide the scrim well bonded to the wadding and such that the composite to the eye and touch appears as an integral sheet; the calendering, however, also largely eliminates the effect of the )crepe in the wadding itself and the composite sheet is relatively stiifened approaching the condition of writing paper, for example. The hot dry creping following the calendering crepes the composite as a whole and the crepe in the wadding appears to the eye to be of somewhat different structure than the original crepe of the Wadding plies; it seems also to be that the fact that the wedding was once creped facilitates the development in the hot dry crepe process of relatively long compressed or creped lengths in contrast to the comparatively short lengths of 'creped structure in the usual crepe sheet. This dry creping action on the composite as a whole changes the sheet structure to a more extensible condition and the sheet to a more roughened but still somewhat stiff product; by an embossing action the sheet is given more flexibility and a good drape characteristic and, importantly, the relatively long crepe increments are broken up and bulked. The nature of the embossing for this latter purpose are preferably such that the embossments imparted to the calendered, creped composite are of a somewhat nubby character.
The invention will be more fully understood by reference to the following detailed description and accompanying drawings wherein:
FIG. l is a plan view illustrating the adhesively treated scrnn;
FIG. 2 is a view illustrating the scrim with covering cellulose wadding layers;
FIG. 3 is a view in section illustrating the relationship of adhesive and scrim in a preferred embodiment;
FIG. 4 is a fragmentary and much enlarged view of a sheet including the wadding following hot calendering;
FIG. 5 is a very much enlarged view following microcreping;
FIG. 6 is a ow chart of steps involved in a preferred embodiment of the process of the invention;
FIG. 7 is a view illustrating a .further embodiment incorporating on the scrim an applique, a portion of a top web being removed to show the scrim and a portion of the scrim being removed to show an underlying web; and
FIG. 8 is a much enlarged view of a window of the scrim generally indicating the applique.
Referring to the drawings, there is illustrated in FIG. l a scrim generally designated by the numeral ll and having a multiplicity of warp threads 2 and filler threads 3. The warp threads predominate and have in this preferred embodiment about l2 threads per inch of LtO-denier nylon (about 3-denier filaments), the fill threads being of 40- denier nylon (about 3-denier filaments) and lesser in number, about 5 per inch. The threads of the scrim carry (FIG. 3), a thermoplastic adhesive 4, suitably a plastisol. The adhesive is present in such amount as to bond the warp and filler threads together at their points of crossover 5; a plastisol serves the adhesive purpose well and such may be, for example, parts by weight of polyvinyl chloride dispersed in 60 parts by weight of diisodecyl phthalate.
Additionally, the plastisol adhesive lies along the warp and ller threads and is available (FIG. 3) for bonding the scrim to overlying cellulose wadding layers. An adhesive excess in the present instance appears as droplets 6 which may be at thread cross-overs 5 or along thread length. The adhesive which bonds the threads together in scrim formation is applied only to the warp threads, for example, and in the present instance is about 3.5 grams per square yard of scrim. Adhesive is applied to the scrim itself to coat the filler and warp threads overall and to provide the droplets or nuggets 6. In the present instance this total of filler thread adhesive and droplet adhesive was about 8 grams per square yard. The coating application is suitably carried out by conventional reverse roll coater although other methods may be used. The development of the nuggets 6, in contrast to completely uniform application of adhesive, results from the applying of the adhesive by roll applicator at a differential speed relative to scrim speed.
The scrim 1 is shown in FIG. 2 as bounded by creped and wet strengthened cellulose wadding layers 7, 8, a portion of which are, for clarity in the drawing, represented as out of contact with the scrim 1. The layers 7, 8 do not bond well to the scrim in the absence of heat and pressure. The wadding layers are creped in conventional manner prior to plying up with scrim and have a crepe ratio of about 1.4 at a drier basis weight of about 12 pounds per 2880 square feet; as is known, the crepe ratio of 1.4 indicates that the sheet material is extensible to about 140% of its crepe length at break and the drier basis weight is the sheet weight before creping. The wadding sheets are wet strengthened by the inclusion of about 0.5% by weight of a standard wet strengthenging agent, melamine formaldehyde. The composite of scrim and wadding is generally designated at 9 (FIG. 2). To secure adherence, the composite is hot calendered (300-350 F.) by conventional procedures to soften the thermoplastic adhesive and press the adhesive coated scrim threads to the wadding. Such action tends to press out and stretch the Wadding so that the composite becomes relatively stiff and smooth surfaced, the product, in fact, losing almost completely the ridgid effect applicable to crepe structures. The adhesive, though somewhat iiuid at the temperature of the calendering action, tends to impregnate the cellulosic wadding; this action is facilitated when the adhesive is present in considerable quantity, as in the form of droplets or nuggets 6, for example. Upon cooling, the adhesive is solidified within the crepe structure as well as along the scrim. In FIG. 4 the adhesive globs or concentrations reformed by the hot calender and subsequent cooling action are designated at 6.
We have found that if the well bonded composite 9 is subjected to a hot and dry creping operation in the warp direction,- for example, the scrim structure internally of the wadding plies will be itself substantially permanently creped together with the wadding. Also, the adhesive will, under the longitudinal compression action involved in crep ing, tend to follow the creped warp threads 2 (FIG. 5). In instances where the excess adhesive has been present in droplets, the presence of relatively large adhesive droplets is apparent; however, even under circumstances of uniform adhesive application, the hot dry crepe action will cause adhesive penetration of the wadding, resulting in localized areas of adhesive concentration and surface roughness in the final product.
Importantly, in the product the adhesive, particularly that portion redistributed somewhat by the hot microcrepe action and indicated'at 6a in FIG. 5, tends to locally harden the material and to rigidly set the hill and valley condition. The hills are designated at 10 and the valleys at 11 in FIG. 5. The adhesive 4 on the creped warp threads 2 is largely, though not completely, retained on the threads throughout the creping action. Some adhesive 4, even in the absence of nuggets 6 on the original scrim, will penetrate the web and be retained as rigid, roughnessimparting elements 6a. An excess of adhesive, particularly when non-uniformly applied to the original scrim, aids element 6a formation. By an excess of adhesive is meant that beyond which it is necessary to bond scrim threads 4 I together and scrimthreads to the waddingv'lIhe adhesive (FIG. 5) while plastic, or molten, during vhot creping of the composite, cools quickly and provides in many instances smooth sided, sharply peaked adhesive nuggets or masses, designated at 12 in FIG. 5. Such provides for product rigidity as to the surface while yet permitting a soft, fiexible, mild abrasive material.
The composite, when stretched in the direction perpendicular to the crepe lines, extends and recovers a very large proportion of the stretch characteristic. This recovery is less than as the structure is noticeably deformable, the recovery being slow in contrast to, for example, a rubber band.
The creping of the composite is, as `already noted, a prime feature and it is carried out very suitably` by microcreping the composite. Microcreped is the term applied to a web having high lengthwise compression at small crepe profile height and is defined and described in U.S. patent 3,260,778 issued July l2,v 1966, vRichard R. Walton, inventor, 'where the equipment employed in the microcreping of the product of this invention is. described. The crepe ratio of' the microcreped product is about 1.2, and the product has ayconsiderable extensibility at break in the direction transverse to the crepe lines, that is, about based on creped length. It also accepts a set when excessively lstretched but such does not noticeably affect the texture or the product feel.
The microcreped product, though stretchable in one planar direction and toughened aswell as roughened by the crepe action, is relatively stiff. To improve the dry feel or hand, the microcreped sheet is embossed utilizing steel or rubber rolls to break up the transverse crepe lines to provide cross-direction drape. This also bulks the product without significant loss of product stretch or toughness. Importantly, the bulky and nubby character of the disposable washcloth is retained when the cloth is well wetted and, consequently, the feel to the hands commonly associated with a washcloth is attained in the wet and dry state of the material.
The washcloth, since it includes the highly absorptive cellulose wadding, retains liquid very Well, is abrasion resistant and may be. printed with decorative designs. The open wadding is somewhat light penetrable, and the use of dyes in the adhesive on the scrimpermits colors of the dyes to show through and provide an attractive and somewhat cloth-like appearance.
For the purpose of providing an increased surface roughness and bulk to the washcloth withoutsacrifice of wettability and water retentioncapacity, we may apply to the formed scrim, prior to lamination with the wadding, an appliqu. This appliqu (FIGS. 7 and 8)'tends to somewhat close over the openings of the scrim, and it may, in some instances, be substituted for the wadding on one side of the scrim. In specific application the scrim is formed in a manner already indicated by coating warp threads with a plastisol, bonding the filler threads 'to the adhesive-carrying warp threads, and'then coating the formed scrim with adhesive. Such scrim material is designated at 14 in FIG. 7. .The plastsol adhesive may be set before the applique is applied but must be in such condition that, in the course of processing, it will adhesively unite with the fibers of the applique; generally, to set the adhesive on .the scrim before the appliqu is applied, the scrim may be heated to about 300 F. and,
for the purpose of adhering the appliqu fibers, the tem-v perature may be raised somewhat higher to about 350. The appliqu itself is `suitably a blend of cotton fibers and heat softenable fibers, the former being indicated at 15 and the latter at 16 in FIG. 7. The heat softenable fibers are very suitably heat shrinkable, suchY as poly-- propylene fibers in some instances have lost their form and have become somewhat beaded.
To the scrim (FIG. 7) an under sheet of wadding 18 is applied and then the material is hot calendered, hot dry microcreped and embossed. Hot calendering (about 350 F.) results in partial fusing of the polypropylene fibers and binding of these fibers in somewhat flattened condition with the cotton fibers; also, the fusible polypropylene fibers tend to lose their fiber form to partially low along the heat resistant cotton fibers and to bond with the scrim fibers or cellulose wadding 18; the microcreping places a crepe in the appliqu fibers further increasing product toughness. For example, the embossing tends to break up the crepe lines increasing product bulk and permitting the cotton of the applique to exert a bulking intiuence.
If desired, a second wadding sheet 19 may be applied over the appliqu prior to hot calendering, and the product then has an appearance similar to that of FIG. but presents a more rough surface.
The heat softenable fibers 16 are a convenient means of providing adhesive to retain the cotton appliqu; it is not necessary that the adhesive be provided as tibers as the adhesive may be applied by other means, for example, coating on the cotton initially.
While preferred embodiments of the invention have been set out, it is to be noted that various modifications may be made while providing a useful washcloth of a quality suitable as a facecloth. For example, the cellulose wadding may be wet strengthened by any generally conventional wet strength agent (melamine formaldehyde, condensation products of polyamide epichlorohydrin and the like) and may have a drier basis weight of between about 8 pounds and 15 pounds per 2880 square feet; also, such wadding sheets exhibit the abrasive resistance and absorbency required. The scrim should be relatively tight and we have employed 6 x 10, 12 x 5 and 6 x 5 scrims, the scrims performing the necessary functions of imparting strength, wet recovery and the like. A scrim Weight of about 13 grams per square yard is typical. The scrim threads preferably are of heat shrinkable material so that, in the hot microcrepe procedure, the threads are shrunk and tend to create a permanent crepe and stretch as well as a mild tufting in the sheet material, characteristics which are retained upon cloth use. Nylon serves the purpose of a shrinkable thread, and other useful threads include polyesters and rayon, for example. The adhesive is provided to be thermoplastic, resistant to water, and plastisols currently are relatively inexpensive and serve the purpose well. When the threads are of heat shrinkable material and the adhesive is softened in the microcrepe process, then, as the threads shrink and as the adhesive sets, the adhesive causes the crepe to be Well retained in what is essentially a permanent condition within normal product use.
As many apparently widely different embodiments of this invention may be made Without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.
1. A laminate in the form of a composite structure comprising a nonwoven open mesh and relatively low stretch scrim of crossed threads, a ply of a wet strengthened cellulosic wadding web on at least one side of said scrim, adhesive bonding the crossed threads of the scrim together and also bonding the scrim threads to the wadding web to form a composite structure, said composite structure being creped and including threads of said scrim having hills and valleys corresponding with hills and valleys of the wadding web, said adhesive being present also in said composite structure as rigid bead-like elements providing a roughness to the wadding web surface.
2. A laminate useful as a washcloth according to claim I in which the scrim has a wadding web on each side.
3. A laminate useful as a washcloth according to claim 1 in which the threads of the scrim which are creped are also of heat shrinkable material.
4. A laminate useful as a washcloth according to claim 1 in which all the adhesive present in the composite is integral with the adhesive on the scrim.
5. A laminate useful as a washcloth according to claim 1 in which the scrim has windows formed by the crossing threads of the scrim and an applique of fluffy liber material is in windows of the scrim on the side of the scrim opposite the wadding, said applique including a heat shrinkable fibrous material.
6. A laminate useful as a washcloth according to claim 5 in which the applique is of a fiber which is relatively heat resistant and a fiber Which is heat fusible.
7. A laminate useful as a washcloth according to claim 1 in which the bead-like elements of adhesive are protuberances of the adhesive which is carried on the scrim threads.
References Cited UNITED STATES PATENTS 3,072,511 1/1963 Harwood 161-57X 3,260,778 7/1966 Walton 264-282 3,307,992 3/1967 Condon et al. 161--57X 3,424,643 1/1969 Lewis et al. 161-57 ROBERT F. BURNETT, Primary Examiner I. J. BELL, Assistant Examiner U.S. Cl. X.R.