US2900980A - Cellulosic product - Google Patents

Description

Aug. 25, 1959 K. J. HARWOOD CELLULOSIC PRODUCT Filed Sept. 30. 1954 Afl.

United States Patent Olice 42,900,980 Patented Aug. 25, 1959 2,900,980 CELLULosIC PRODUCT Kenneth J. Harwood, Neenah, Wis., assignor, by mesne assignments, to Kimberly-Clark Corporation, a corporation of Delaware Application September 30, 1954, Serial No. 459,473

18 Claims. (Cl. 12S-290) This invention relates to an improved cellulosic product, iand more specifically, an improved sanitary or catamenial napkin which embodies an absorbent pad element and a Wrapper around such pad element, and to an improved form of material adapted for use in such Wrapper and for other purposes. Although other Wrappings materials are being used around pads, the most common wrapper material has been woven` surgical gauze which provides Ia highly pervious Wrapper which permits the menstrual exudate `to readily pass through thewrapper and 'be absorbed by the absorbent pad. Gauze has been very satisfactory for the indicated purpose because of its substantial tensile strength which enables such material to effectively hold and confine the absorbent pad and to provide attachment tabs which extend beyond the ends of the absorbent pad for supporting the napkin from a belt or garment through the agency of buckles or pins.

i Gauze wrappers for sanitary napkins have, however,

lheen somewhat objectionable in several respects. For example, gauze threads are fairly hard and tend to be quite abrasive against the skin of the wearer of the napkin so `that chang and irritation are likely to occur. This abrasive effect has been avoided in certain products by the application of la facing of free, unspun and unfelted yor only loosely felted fibers, `such 4facing being very light in weight and just suilicient to produce more or less `of a shielding effect over the gauze threads, the Weight of the fiber applique being also kept very low in order to avoid as far as possible, reduction of the permeability of the gauze material. An example of that construction is shown in U.S. Patent Patent No. 2,564,689.

The Weaving of gauze is a relatively slow operation,

many gauze weaving looms being operated tat the rate of about one and one-half feet per minute when weaving gauze having a thread count of 18 x 14 (18 lengthwise threads per inch of Width and 14 crosswise threads per inch of length) and a fairly strong and tightly spun thread is used to avoid thread breakage in the Weaving operation. Hence, the threads found in woven gauze are ordinarily hard and abrasive as aforesaid. Also, for sanitary napkin wrapper purposes, a very open mesh gauze is most suitable in order to provide the greatest permeability. However, although gauze more open than 18 x 14 may be woven, the more open weaves are seldom satisfactory because they tend readily to fray or become distorted, that is to say, the threads tend readily to shift from their normal positions, providing uneven and unsightly thread disposition in the relatively unstable, more open weaves. In ,18 x14 gauze webs which have heretofore been generally used' for sanitary napkin Wrapper purposes, the weight of the gauze averages about 16 to 16.5 grams, this being an important factor in the total weight of the sanitary napywhich desirably is made as light in Weight as possible without impairing its functions.

Another diiculty in respect of the use of gauze of more open mesh for sanitary napkin wrapper purposes is incident to the necessity of employing Well bleached gauze in order to obtain the desired clean, white and sanitary appearance. As a practical matter gauze is woven from unbleached cotton threads `and the woven fabric subjected to bleaching operations. Conventional bleaching operations involve `substantial handling of the fabric which may Ibe accompanied by severe and extensive fraying even in such meshes as 18 x 14 and the fraying becomes more severe as the mesh is made more open. For sanitary napkin wrapper purposes, it is important that the wrapper Ifabric be of uniform thread distribution, that is to say, free from distorted thread lay or fraying, in order that the product present a very neat appearance, and for other reasons.

ln some prior Lattempts to avoid the employment of woven gauze for sanitary napkin purposes, various porous paper and non-Woven fabric sheetings have been substituted for gauze, but even in such substituted constructions it has usually been found necessary to incorporate at least a narrow strip of gauze extending from end to end of the napkin, i.e., from the free end of one attachment tab to the free end of the other attachment tab, so as to provide the necessary `strength for supporting the napkin in the usual manner. Also, paper Iand non-Woven fab-ric Wrappers must be made sufficiently strong to effectively retain and to support the absorbent pad and this requirement necessitates the use of such heavy or dense paper or nonwoven fabric that perviousness has been quite objectionably impaired.

According to the present invention, la wrapper is provided which consists yof textile or other threads extending lengthwise and crosswise as in la Woven gauze sheet but in which the threads are not interwoven or interlaced but are otherwise securely held in fixed relationship to each other so that the fabric is highly stabilized and may be of almost `any desired very open mesh, for example, 4 x 4. Known apparatus, not a part of the present invention, is capable of operation at many times the production speed of gauze weaving looms, to produce such fabric. Fabric made of such cross-laid threads, is referred to hereinafter =by the Words crosslaid fabric.

The main objects of the present invention are to provide a sanitary napkin embodying an absorbent pad element and a Wrapper around such pad element wherein the wrapper embodies a stable thread web of very open mesh so as to be highly permeable; to provide a sanitary napkin of the character indicated in which the wrapper is soft and flexible so that 'it is readily conform- -able to the enclosed pad body; to provide a napkin o-f the character indicated in which the covering wrapper embodies strength and security giving threads but nevertheless exhibits comfort giving characteristics of nonirritating or non-chang surface softness and smoothness; to provide an improved fabric embodying Strength giving threads, which fabric is suitable for many purposes including use as a sanitary napkin Wrapper having the aforesaid desirable characteristics; and in general, it =is the object of this invention to provide an improved absorbent bandage such as a catamenial napkin and an improved fabric which is suitable for the vn'apper com,- ponent of such a napkin and for other purposes.

Other objects and advantages of the invention will be understood by reference to the following specification and accompanying drawing wherein there is illustrated a selected form of the 'improved sanitary napkin.

In the drawing:

Figure l is a perspective illustration of a sanitary napkin;

Figure 2 is an elevation of a piece of fabric made aecording to this invention and used in the wrapper of the sanitary napkin;

Figure 3 is a perspective representing an element entering into the construction of the fabric material shown in Figure 2;

Figure 4 is a cross-sectional view on the line 4-4 of Figure 2;

Figure '5 is asection on .the line 5 5 of F1g11re 2; and

Figures 6 and'7 `are schematic representations of method steps and mechanisms for producing 'certain components of the improved sanitary napkin. v

A sanitary napkin, represented in Figure 1, comprises an absorbentpad body 1 which may be of any suitable construction, the details of which are not important or critical so far as the present invention is concerned. This absorbent pad body, in one embodiment, was formed of a combination of crepe tissue paper plies and an intermediate layer of Aso-called duff material, end portions of the crepe paper plies V'ex-tending beyond the intervening utf layer and being embossed under substantial pressure and thereby united so as to aid in holding the Vintermediate fluff layer in place. The pad body 1 is enclosed in a wrapper 2 which is initially inthe formy of an elongated rectangular sheet or web of material, such web being wrapped around the pad body 1 transversely of its length so that opposite side margins of the wrapping sheet overlap one another as indicated at 3 in overlying relation on one face of the pad body l. The wrapper 2 is thus formed into more or less of Ia tube about the absorbent pad 1, end portions 4 and 5 of the wrapper projecting beyond the opposite ends of the pad 1 to constitute the usual attachment tabs for engagement with the buckles of a supporting sanitary belt or other supporting means. In some instances the tabs maybe'shortened and provided with attachment loops in a known manner.

The wrapper 2 of the napkin is formed of a cross-laid thread backing or carrier web 6 comprising a series of spaced, substantially parallel lengthwise extending threads 7 and a series of spaced, substantially parallel crosswise extending threads 8, and an applique 9 of fibers. The threads S, in this instance, are disposed substantially perpendicularly to the threads 7 so as to resemble woven gauze, and said threads S are adhesively bonded to said threads 7 by adhesive 1d on the threads '7, said adhesive serving to also bond said fiber applique to the threadformed web. If desired, the cross-laid threads 7 and 8 may be disposed diagonally of the length of the web so as to present a diamond network pattern, and there may be one or more additional sets of threads cross-laid on those illustrated, the threads of such additional sets being disposed at angles to the threads of both of said other sets. Parallel thread `arrangement is not essential and may give way to non-parallel threads including various arrangements such as sets of wavy or undulating threads which threads may extend in one general direction without necessarily being parallel to one another.

The adhesive i6 on the threads 7 is preferably applied so as to be discontinuous along the lengths of sa-id threads, irregularly spaced breaks or interruptions in said adhesive being indicated at lll. The cross threads 8 will seldom engage adhesive-free areas on adjacent lengthwise threads so that said cross threads will, not withstanding said adhesive-free lengths, become effectively bonded to the adhesive-bearing threads. The cross threads are caused to engage adhesive bearing areas of the lengthwise threads with sucient intimacy to insure adhesive interbonding of said lengthwise and crosswise threads, and calendering of the web may be employed to increase or amplify such intimacy. Due to this adhesive interbonding of the lengthwise andcrosswise threads it is very practicable to'produce stable cross-laid thread webs having such open mesh construction as: 4 x 4. The example represented in Figure 2 of the drawing is l0: x 5 construction, Figure 2 being greatly enlarged. v The fiber applique'9 may consist of natural or synthetic fibers or mixtures thereof and said fibers may be deposited ina more or less haphazard arrangement as represented in Figure 2 so that some, if not most, of the fibers will engage at least one `adhesively coated thread portion so as to be thereby directly adhesively attached to the thread web. The fibers which form the applique 9 also have a normal tendency to cling to engaged thread portions even in the absence of adhesive so that an important degree of cohesion exists between the fibers and the engaged portions of the adhesive-free cross threads 8. Furthermore, intertwining of the'tbers in the applique also serves to anchor bers to iibers so that a fiber which happens to miss engagement with any thread of the thread web may nevertheless be anchored thereto through the agency of other bers which are directly attached to the thread web. Carded and similar fiber webs may also be employed to form the fiber applique. The fiber applique may be preformed and applied to the backing web or the applique may be formed on the backing web by depositing thereon libers dischargedin unmatted or free condition from air-laying, carding, and other forms of free fiber delivering apparatus.

The ber applique may be of any desired weight suitable for any given use to which the fabric is to be put. For sanitary napkin wrapper purposes the fiber applique '9 may be very light, for example, of the order of 11/2 to 6 grams per square yard.

The fiber applique 9, even when made of very low basis weight, for example, within the range of 11/2 to 6 grams per square yard, provides a signicant shielding elfect whereby the threads of the carrier web are held out of intimate contact with the body of the wearer of thenapkin so that chai-lng and irritating tendencies incident to the normal hardness and abrasiveness of the cross-laid threads is largely avoided. Calendering will aid in this matter of avoiding chang tendencies, by more or less attening the crossing areas of thelengthwise and `crosswise threads so that the wrapper material exhibits an important freedom from pronounced thread crossing projections or knuckles such as occur Vin Woven gauze.

By applying `the adhesive only to the threads extending in one direction as above explained, the normal softness and iiexibility of the other threads is preserved as a characteristic of the fabric. Also, by applying theadhesive in short lengths so as to provide the adhesivefree areas 1l at short intervals, the normal flexibility and softness of the adhesive-bearing threads is also `preserved to a significant degree. Furthermore, it is Vpreferred that the `adhesive `be of a permanently flexible character so as to thereby further avoid adhesive hardening or stiiening of the fabric.

Vsoak into the same is desirable to facilitate embedment -of some of the bers of the applique `9 into said adhesive,

and also embedment of one set of threads in the adhesive carried by the other. Also, surfaced adhesives usually have a lesser hardening eifect onfthe threads.

lOne form of mechanism for producing the illustrated cross-laid fabric, is schematically represented in Figure 6 where the longitudinal threads 7 are represented asbeing guided over an adhesive coating roll 12 and thence into the lform of a cylinder around aimandrel-l. Suitable means indicated at 13a may be employed to-guide the threads into the desired spaced relation around said mandrel. The cross threads 8 are Wrapped .around the thread cylinder `on the mandrel-by -a rotating device 14 and becomes adhesively bonded to said threads .7 by the adhesive on the latter. The cylinder of cross-laid threads is slit as indicated at.15 and laid open and then passed between the rolls .of acalender roll stack as rep*- resented at 16. Depending upon the type of adhesive used, provision rmay be made to -dry or partially dry jthe adhesive on the threads to prevent-wet adhesive from 'hesive on the longitudinal threads.

gumming up the guide means 13a and mandrel 13, and suitable means may be provided, for example heating or moistening means, for reactivating the adhesive at the required time to make such yadhesive useful for bonding the threads together and other components to the threads. Other mechanisms for producing the cross-laid thread fabric may be employed, the schematically represented mechanism just described being merely representative.`

To produce the adhesive free areas shown atf11 (Figure 2) on the threads 7, the adhesive applyingi roll 12 may be formed with recesses (not shown) which will not apply adhesive in the areas 11`or said roll `may be of plain cylindrical form and rotated so as to have a surface speed which is slower than the speed of travel of the thread web, whereby the faster movement of the threads would tend to stretch the adhesive as it leaves the roll; such stretching of the adhesive will cause frequent but irregularly spaced breaks in the adhesive on the threads so that the adhesive will, in effect, be discontinuous along the lengths of the threads 7.

In some instances, instead of applying the adhesive by means of an applicator roll the threads may be coated continuously with adhesive by being passed through a bath of the desired adhesive. The adhesive may be prepared so that the threads passed through such a bath will pick up adhesive coatings of the desired thickness and surfacing tendencies. Also, suitable doctoring means may be employed in association with either or both the threads and an applicator roll to control the thickness of the adhesive coating on the threads.

The cross threads 8 and the fiber applique 9 are preferably deposited on the adhesive bearing threads 7 while at least the surface of the adhesive remains sufciently active to adhesively bond the cross threads and the fibers to the adhesive bearing threads substantially upon contact of the cross threads and fibers with such adhesive. The cross-1aid web may be guided from the cross-laying mechanism through fiber depositing mechanism as represented at 18 in Figure 7, the calender stack 16 being by-passed and its function performed by a calender 19 after `application of the fiber applique so that the fibers in addition to the cross threads are pressed into the ad- Said calender 19 preferably embodies steel and cotton or other relatively hard and soft calender rolls 21 and 22 respectively which will serve the aforesaid purpose without causing cutting or breaking of the threads at the points of greatest pressure, i.e., at the thread crossings.

A hot calendering operation may be employed, especial-ly when the adhesive is of thermoplastic character, the heat then serving to reactivate the adhesive so as to facilitate embedment of threads and fibers in such adhesive. As indicated in Figure 7, it is preferred that the cross-laid web be passed through the liber depositing apparatus so that the fibers will be deposited on the side of the web formed by the set of adhesive free threads, so that the longitudinal threads will serve as strippers to remove the cross threads and fiber applique from the cotton calender roll; also, the fiber applique and cross threads will then prevent adhesive attachment of the longitudinal threads to the calender roll 2l, and some of the fibers of said applique will aid in anchoring the set (or sets) of adhesive-free threads to the adhesive bearing threads as an incident to Ithe adhesive attachment of such fibers to said adhesive bearing threads.

Instead of applying adhesive to the threads, said lengthwise threads, or the cross threads, or both, may be formed of a mixture of cotton or other non-thermoplastic fibers or filaments, and thermoplastic filaments or fibers, the threads being subjected to heat or other treatment to cause the thermoplastic component thereof to be sufficiently activated to effect adhesive inter-attachment of the mutually crossing threads. It is preferable when procuring bonding in this manner, that the set of threads on which other threads and fibers are deposited, contain thermoplastic fibers and be subjectedto a thermoplastic fiber softening operation (heating, for example) before the other threads and fibers are deposited thereon. VIn this manner the deposited threads and bers will be` at leastl slightly adhesivelyattachedto the thermoplastic bearing threads immediately upon `contact therewith. Again, the `adhesive bonding thus effected between the lengthwise and crosswise threads of the carrier web 6 and between the fibers of the applique 9` and the carrier web, may be improved by again or further reaotivating the thermoplastic `fibers by a hot calendering operation whereby more` complete embedment of the interbonded threads and fibers may be effected. The fiber applique 9 may also embody a percentage of thermoplastic fibers (say from 5 to 15 percent or more), which will be reactivated and adhesively bonded to the threads of the carrier web as an incident to said hot calendering operation. In some instances, the binder bers in the applique may alone be relied upon to hold the threads of the carrier inrsubstantially fixed relationship to each other.

At least `one of the sets of threads 7 and 8, comprises threads of soft, low twist construction and both sets may advantageously be entirely of such construction. Said threads may contain, for example, from 2 to 150 individual continuous filaments per thread, the filaments being fairly fine filaments, i.e., of the order of l to 15 denier rayon,` the threads being of 30 to 150 denier and having a twistless than 6` per inch, but at least .a slight twist is desirable to hold the filaments together as an integrated thread. Filaments of material other than rayon may be used but rayon has been found to be very suitable.

In one practical embodiment, the cross direction threads 8 were made of 40 rayon filaments to forma low twist thread of denier, the twist being of the order of 4 turns per inch. The machine direction threads 7 were made of 30 rayon filaments to form a low twist thread of 75 denier, the twist being of the order of 21/2 turns per inch. These low twist fine filament threads 7 and 8, although initially of more or less round cross-section, tend to assume a flattened oval shape in cross section as indicated at 20 in Figure 3, incident to winding of the same on spools and as an incident to the passage of the-threads over guide rods or rollers.` When such threads are fabricated into the described cross-laid thread fabric 6, this iiattened `cross-sectional form is advantageous in that the Width of the threads falls into the plane of the fabric; hence, the crossings of the threads are initially quite flat and this atness is increased, or to put it in another way, the thickness of the initially flat crossings is reduced, when the web is calendered as above mentioned.

The flattening of the threads as above explained provides a further advantage in that flexibility of the fabric is improved due to the increased fiexibility of the threads.

The multiple filament, low denier, low twist construction of the threads employed in the thread carrier web results in a thread fabric which is very thin, soft and smooth notwithstanding the tendency of adhesive to impart stiffness to the fabric.

Th inherent softness of said low twist threads permits the filaments in the crossing thread portions to fan out to widened and iiattened proportions as a result of thepressure of interengagement which is incident to the tension under which the threads are assembled in the web. This flattening and widening provides enlarged areas of engagement and adhesive interattachment of the mutually crossing thread portions, said flattening and widening is, of course, increased by the subsequent calendering operation which attens not only the crossing portions but the entire lengths of the threads so that in the finished nonwoven carrier web 6, a highly desirable flatness and smoothness is attained. If the adhesive on the threads is of heat sensitive character, hot calendering will aid in the flattening effect. i i t Because of the .soft `low twist construction of the threads, relatively ,low calendering pressure (for example about 85 pounds-perlineal inclrof contact area when the rolls-are about `8inches in diameter) is sufficient to producea very-satisfactory flattening effect. This relatively low calendering pressure avoids the tendency of the threads to cutone another when rthey arepressed together .under highl pressures such as are required when the `threads, are of harder, high twist Vconstruction as in Woven gauze. Thecalendering operationreduces the combined thickness of -the two interengaging, crossing thread portionsalmost to the thickness of the single thread portions intermediate said crossings as shown in Fig. 5, the thicknesses Vreferred to being normal to the plane of the web.

Because of the softness of the described low-twist, multiple filament threads, the cross thread portions intermediate the longitudinal threads, tendto` settle into the plane of said longitudinal threads upon deposition of the cross threads onrthe longitudinal threads as shown (more or less schematically) in Fig. 4. Thisinitial nearly coplanarrelationship is made more nearly complete as an incident to thercalendering of the carrier web 6 with the fiber applique 9 thereon, the interengaging crossing thread portions being pressed into each other as above explained. Thelongitudinal threads are initially disposed in coplanar relationship, and this relationship is not disturbed'in thefabricating operations, so that the layer of longitudinal threads presents a substantially smoother surface than is found on comparable woven fabric.

The applique 9 of fibers, where said fibers cross over thread portions, are pressed into compacted, intimate engagement with said thread portions, while in the areas `of the openings or interstices of the backing web, which Aopening areas comprise a great majority of the area of the web, the fiber applique 9 exhibits a characteristic softness or flufliness. The very open mesh character of the web 6 probably contributes to the tendency of the fiber applique to assume the said soft fiuffy condition in the spaces between threads. Hence, the fiber applique 9, even though securely bonded tothe threads of the carrier web will nevertheless provide a soft cushion-like facing on the carrier web.

'In onepractical'embodiment of the described crosslaid thread fabric of 18 X 14 construction with cross threads of aboutlOO denier former of 40 rayon filaments of about 2.5 denier, and machine Vdirection threads of about 75 denier formed of 30 rayon filaments of about v.2.5 denier, `the weight kof the cross-laid thread fabric,

including `the adhesive but no fiber applique, averages between 13 and -l4 grams per square yard, theadhesive accounting for about 4 grams of said weight. A Woven gauze fabric of 18 x 14 construction embodying the usual s Warp and Y40s filling, weighs an average of'about 16.3 grams per square yard. This comparison indicates the substantial reduction in weight which is attained in cident ito the employment of the described cross-laid thread fabric instead of woven gauze. This weight reduction is practicably attainable incident` to the feasibility of producing the cross-laid, `non-woven thread fabric of threads of the aforesaid soft character and light weight. Weaving with such light weight threads toproduce cornparable woven gauze, especially at high production speeds desired, is very difficult'due to various factors such as the smooth, slippery surface characteristic of such threads; woven gauze produced from such threads frays very easily so that itsusefulness for sanitary napkin wrapper and other purposes is ygreatly impaired.

In another practical embodiment of the described sanitary napkin, the wrapper 6 comprises a l0 x 5 thread `web-formedfof about75 denier lengthwise threads and aboutlO() denier crosswise threads, the lengthwise threads being.'v formed of 30 laments of about 2.5 denier and the crosswise threads of 4() filaments of about 2.5 denier.

.-Thew'ebf4 so formed 4fweighs about 7 grams per square similar Woven gauze wrapper of the usualrBOs warp and .40S filling .weighs about 9 grams per Square 'yard-but despite itsextra weight and strength, would not, be very satisfactory as .a ,Sanitary napkin wrapper tiennent''because ofits excessive ,fr aying or distorting tendency. On the last mentioned crossalaid thread carrier web, there was air-laid, a non-woven facing of comber cotton fibers having a weight 4of about 31/2 grams Vper square'yard. This resulted in a very satisfactory, highly liquid-permeable Wrapper for the absorbent ,pad of the sanitary napkin. The grade of cotton referred to as lcomber cotton comprises fibers ranging in length from about #A6 of an .inch or even less to l inch `or more withV a large proportion of the fibers being of an intermediate length around TA6 ofan inch.

The thread forming filaments were of rayon having very smooth and shiny surfaces which imparted to the wrapper, a very desirable appearance. However, rayon filaments having a dulled, non-shiny surface-finish are available and may be employed if preferred.

-lnprodticingthe above mentioned l0 x 5 cross-laid thread web, `plasticized polyvinyl acetate adhesive in a solvent was applied togthe Vmachine direction threads by an immersion process. Thecross threads were deposited on the `adhesive bearing longitudinal threads while the adhesive on the latter remained active at least `on the surface of the adhesive so that the cross-'laid threads were immediately adhesively heldinpllace on the lengthwise threads. The thread web thusproduced was then passed through a machine. whereby. fiber was air-laid on the cross thread side ofthe web. Thereafter, the fiber applique bearing web Vwas calendered to'flatten'the threads and theircrossings, to improverthe embedment of the cross threads in the adhesiveron the longitudinal threads, and to also effect embedment of some of the'fibers of said applique into said adhesive, thereby to securely'bond the vvarious parts ofthewrapper to each other.

The calendering equipment included the heated steel Vrol-l represented at 2l in Figure U7, and a cotton calender roll 22, the web being passed through the calender with theflongitudinalthreads of the web next togthe cotton -roll which-is normally the cooler of the-two rolls. I n `this arrangement the fibers of the fiber applique werealso vpressed into the space between the longitudinal threads as above explainedand as represented in Figure 4. -The steel roll was heated to` a temperature of about 300F. The calendering was effected under apressure of about pounds per lineal inch of calender roll (about eight inches in diameter) and this pressure was sufficient to somewhat. increase the flatness of .the threads, especially at their crossing portions so thatthe cross-laid threadfabricvis much smoother to the feel than comparable woven gauze.

Fabric embodying a l0 X 5 carrier web and a fiberapplique weighing within the range of 1% to 6 grams per square yard is very porous since the threads in the carrier webare substantially spaced from each other, and because the fiber applique is so light and porous and permeable that there is but little resistance to the passage of fiuid through the fabric. Such material is well suited to sanitary napkin wrapper purposes because it readily permits menstrual fiuid to penetrate the wrapper for absorption by the absorbent pad. Also, when the fiber applique is within said weight range of 11/2 to 6 grams per square yard, there is such relative paucity of fibers per unit of web area that a large percentage of the fibers will directly contact adhesive bearing thread portions to be thereby adhesively bonded to the carrier web. Hence, the applique, as an entirety, is effectively bonded to the carrier web so that detachment of the fiber appliquerfrom the carrier web by rubbing and scufiing does not readily occur.

Fiber faced webs such as described, notwithstanding their stability due to the adhesive interbonding of the threads in the thread carrier Web, are very soft and :pliable so vas to be readily conformable to absorbent pads A 9 to make sanitary napkins and such webs are readily foldable about such pads by high speed, automatic pad wrapping mechanism. The thread portions which are free of adhesive intermediate bonded intersections contribute substantially to the softness of the web as does also the working of the threads incident to the passage of the web through a calender as aforesaid, the latter operation probably serving to break up the continuity of the adhesive coatings along the thread portions intermediate some of the bonded intersections or perhaps to reduce the thickness of the adhesive coatings, to make them more flexible. The low twist, fine denier, multiple filament, Very fiexible thread construction, also contributes to this softness as aforesaid.

From the foregoing it will be seen that Whereas limitations in respect of the manufacture of gauze necessitate the use of constructions which provide much greater strength than is required in a sanitary napkin wrapper and also greater stiffness than is desired, the cross-laid thread `webconstruction herein described permits much greater freedom in the selection of threads and permits the use of much lighter or thinner threads which nevertheless provide,` adequate tensile strength for sanitary wrapper purposes. The lighter or finer threads which may be used in cross-laid fabrics are of adequate strength, `due `in part to the adhesive bonding of the` filaments to each other, and probably 'to a greater extent, to the fact that the threads are made of continuous filaments.

, The low twist multiple filament threads employed for making the carrier web will normally assume positions with their flat faces paralleling the plane of the web andsuch fiat faces of the relatively crossing threads provide fairly wide fiat areas which are adhesively bonded to` each other. Effective adhesive bonding is, therefor, easily attained. Similarly, the fibers of the fiber applique are most effectively bonded to the carrier web because of the wide adhesive bearing faces which said threads present` to the fibers. i'

The 30 and 40 lament thread constructions described as having `been employed in practical products, are not critical or essential; .they may be varied withinthe aforementioned fairly wide range and especially in the direction oflower numbers of filaments in the threads. Lower denier filaments and threads may also be used without making the web too weak for sanitary napkin wrapper purposes.' Heavier weightsmay also be used but those specified are considered adequate and the use of thread weights which would equal woven gauze thread weights is unnecessary and undesirable for both functional and economic reasons.

An example of another satisfactory, lighter weight web would include a' fiber applique of 1.5 grams per square yard on a cross-laid thread web of 4 x 4 construction composedof low twist, multi-filament, lengthwise and crosswise threads of 75 denier formed of 30 filaments.

Stable cross-laid thread fabric such as described, may be formed of low twist, cross-laid threads to suit various uses, the specifications of the threads within the stated ranges and the` closeness of their lay being selected to suit the various uses. Such fabric may be provided with a fiber applique of suitable weight or density if` desired or the fabric may be used without such applique as best suits the specific purpose for which the fabric is selected.

Various combinations of the above mentioned Vvariable factors may be `employed to obtain suitable cross-laid fabrics for sanitary napkin wrapper and other purposes, and other changes may be made while retaining the principles of and attaining the attributes of the described constructions. i

I claim: i i

1. Non-woven netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of those ofthe other set and wholly on one side thereof,isaid sets f threads being adhesively bonded to each other at the crossingsof their threads, the threads of at least one of said sets comprising multiple lament low twist threads having a twist less than 6 turns per inch and a denier within the range of 30 to 150, whereby a relatively light pressure on said low twist threads will flatten the threads and increase their flexibility.

2. Non-Woven netting comprising two sets of spaced threads disposed in face-to-face relation to each otherA with the threads of one set extending transversely of4 those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each other at the crossings of their threads, the threads of at least one of said sets being of low twist, multiple filament construction in which the filaments are of a denier within the range of about 1 to 15 and the twist is less than 6 turns per inch.

3. Non-woven netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each other at the crossings of their threads, the threads of at least one of said sets being of low twist, having a twist less than 6 turns per inch, and of multiple filament construction of a denier within the range of about 30 to 150 and formed of filaments having a denier within the range of about 1 to 15.

4. Non-woven netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each.v other at the crossings of their threads, the threads of at least one of said sets being of low twist, having a twist less than 6 turns per inch, and of multiple filament construction with their portions which cross portions of the threads of the other set flattened and widened to provide greater flexibility as well as enlarged areas of engagement and adhesive attachment to said threads of the other set.

5. Non-woven, fiber-faced netting comprising two sets of spaced threads disposed in faceto-face relation to each other with the threads of one set extending transversely of those of the other set Wholly on one side thereof, said sets of threads being adhesively bonded to each other at the crossings of their threads, the threads of at least one of said sets being of low twist construction having a twist less than 6 turns per inch, with the portions of said low twist threads which cross portions of the threads of the other set flattened and widened to provide greater flexibility and enlarged areas of engagement and adhesive attachment to said threads of the other set, and a non-woven Vapplique of fibers attached to a face of said web. i i

6. Non-woven fiber-faced netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each other at the crossings of their threads, the threads of at least one of said sets being of low twist, having a twist less than 6 turns per inch, and of multiple filament construction with their portions which cross portions of the threads of the other set iiattened and widened to provide enlarged areas of engagement and adhesive attachment to said threads of the other set, and a non-woven applique of fibers secured to a face of said web, said web and applique being calendered whereby said applique is compacted in the areas of said threads but preserved in comparatively fluffy condition in the areas of the interstices of said web.

7. Non-woven netting comprising at least two sets of spaced threads of low twist construction disposed in facetofface relation to each other with the threads of at least one set extending transverselyV of those of another set, said threads having a twist less than 6 turns per inch, the

threads of said one set having adhesive applied discontinuously along their lengths and the threads of said other set being -free of adhesive except where they cross and engage adhesive-bearing areas of the threads of said one set, the interengagement of lsaid threads in said adhesive bearing areas serving to adhesively bond said thread sets to each other.

8. Fiber-faced, non-woven sheet material having a web comprising at least two sets of lspaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of those of the other set wholly on one side thereof, the threads of at least one of said sets of threads having adhesive along their lengths, said adhesive bonding crossing thread portions to each other to thereby bond said sets of threads to each other, some of the thread portions intermediate said bonded crossings being substantially free of adhesive, the threads of at least one of said sets being of low twist, multiple filament construction having a twist less than 6 turns per inch and being of a denier within the range of about 30 to 150, and a non-woven facing of fibers on a face of said web engaging the adhesive on said adhesive-bearing threads and thereby attached toV the web.

9. A sanitary napkin comprising an absorbent pad and a wrapper enclosing said pad, said wrapper comprising at least two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extend ing transversely of those of the other set entirely on one side thereof, at least one of said sets of threads comprising low twist, multiple filament threads having a twist less than 6 turns per inch and being of a denier within the range of 30 to 150, whereby said low twist threads respond to forces on the wrapper to assume a flattened cross-sectional form which falls generally into the plane of the adjoining surface of said absorbent pad to thereby provide a smoother, softer and more lieXible surface with the pad.

l0. A sanitary napkin having an absorbent pad and a wrapper enclosing said pad, said wrapper comprising a set of spaced threads which extend in one direction, and a second set of spaced threads which extend transversely of the threads of said first mentioned set entirely on one side thereof, said sets of threads being adhesively bonded to eachother at the crossings of their threads, and the threads of both sets being of low twist, multiple filament construction, said threads having a twist of less than 6 turns per inch, said wrapper being significantly more supple than conventional woven cotton gauze of like mesh made of 30s warp and 40s filling threads, and a nonwoven applique of fibers on a face of said wrapper.

1l. A sanitary napkin having an absorbent pad and a wrapper enclosing said pad, said wrapper comprising a set of spaced threads which extend in one direction, and a second set of spaced threads which extend transversely of the threads of said first mentioned set entirely on one side thereof, said sets of threads being adhesively bonded to eachother at the crossings of their threads, the threads of both said sets being of low twist, having a twist less than 6 turns per inch, and said threads being of multiple filament construction having a denier vwithin the range of 30 to 150, said wrapper being calendered and the filaments thereof caused to fan out to form thin fiat crossing thread portions having a combined thickness which is significantly less than the sum of the normal thicknesses of said threads transversely of the plane of the Wrapper.

l2. A sanitary napkin having a wrapper and an absorbent pad, said wrapper comprising a set of spaced threads which extend in one direction, and-a second set of spaced threads Iwhich etxend transversely of the threads of said first mentioned set entirely on one side thereof, the threads of at least one of said sets being of low twist, multiple filament construction having a twist less than 6 turns per inch and having a denier within the range of about 30 to 150, the filaments having a denier 12 within the range of 1 to 15, and said sets of threads being adhesively bonded to each other at the crossings of their threads.

13. A sanitary napkin having an absorbent pad and a Wrapper enclosing said pad, said Wrapper comprising a thread web having a set of spaced threads which extend in one direction, and a second set of spaced threads which extend transversely of the threads of said first mentioned set entirely on one side thereof, the threads of both of said sets being of low twist, multiple, fine filament construction, the low twist of said threads being less lthan 6 turns per inch so that 1where said threads cross one another, the filaments fan out to form wide but thin, fiat crossing thread portions which have their fiat faces in engagement with each other, said fiat faces being adhesively bonded to each other to thereby stabilize the thread positions in the fabric, and a non-woven applique of fibers on a face of said thread web and adhesively secured to some of said threads.

14. A sanitary napkin having an absorbent pad and a wrapper enclosing said pad, said wrapper comprising a thread web having a set of spaced threads which extend in one direction, and a second set of spaced threads which extend transversely of the threads of said first mentioned set entirely on one side thereof, the threads of at least one of said sets having a twist of less than 6 turns per inch, one of said sets of threads having adhesive applied thereto along their lengths and the threads of the other set being free of adhesive but engaging said adhesive on said adhesive-bearing threads and being thereby bonded to said adhesive-bearing threads, and a non-woven applique of fibers on the side of said wrapper formed by said adhesive-free threads, some of the fibers in said applique engaging said adhesive bearing threads intermediate said transversely extending threads to thereby adhesively anchor said applique to said thread web, said .applique being pressed into said thread web and being compacted therewith at crossings of the fibers over the threads but remaining comparatively fluffy in the areas of the interstices of the web.

15. Non-woven netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of and crossing those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each other at at least some of the crossings of their threads, at least one of said sets of threads comprising highly fiexible, low twist threads, having a twist less than 6 turns per inch, the netting being calendered and said low twist threads being thereby caused to fan out to form thin, flat, widened portions at their crossings, whereby the prominence of said crossings is reduced, the area of adhesive attachment of the thread portions in said crossings is increased, and the fiexibility of the netting is increased.

16. Non-woven netting comprising two sets of spaced threads disposed in face-to-face relation to each other with the threads of one set extending transversely of and crossing those of the other set wholly on one side thereof, said sets of threads being adhesively bonded to each other at at least some of the crossings of their threads, both of said sets of threads consisting of highly flexibly, low twist threads, having a twist less than 6 turns per inch, the netting being calendered and said low twist threads being thereby caused to fan out to form thin, flat, widened portions at their crossings, whereby the prominence of said crossings is reduced, the area of adhesive attachment of the thread portions in said crossings is increased, and the flexibility of the netting is increased.

17. Non-woven sheet material having a web comprising at least two sets of spaced threads disposed in facetofface relation to each other with the threads of one set extending transversely of those of the other set wholly on one side thereof, the threads of at least one of said sets being of low twist, multiple filament construction having a twist less than 6 turns per inch and being of a denier within the range fo about 30 to 150, one of said sets of threads having adhesive along their lengths and the other set of threads being free of adhesive but being bonded to said adhesive-bearing threads by the adhesive carried by the latter.

18. Fiber-faced, non-Woven sheet material having a web comprising at least two sets of spaced threads disposed in face-to-face relation to each other With the threads of one set extending transversely of those of the other set and wholly on one side thereof, at least one of said sets of threads being of low twist, multiple lament 14 construction with a twist less than 6 turns per inch, and a non-Woven facing of fibers on a face of said web including a quantity of thermoplastic fibers which are activated by hot calendering of the web to provide bonding 5 of the threads and ber facing in relatively iixed positions.

References Cited in the le of this patent UNITED STATES PATENTS 10 2,564,689 Harwood et al Aug. 21, 1951 2,696,243 Holland Dec. 7, 1954 2,771,118 Bobkowicz Nov. 20, 1956

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