US3834983A - Process of forming wet laid tufted non-woven fibrous web from a viscous fibrous dispersion and product - Google Patents

Abstract

A TUFTED NONWOVEN WATERLAID WEB MATERIAL EXHIBITING HIGH LOFT, BULK AND ABSORBENCY IS COMPRISES OF A SUBSTANTIALLY PLANAR WEB BODY PORTION OF RANDOMLY ARRANGED WATER DISPERSIBLE FIBERS AND A MULTITUDE OF SEPARATE, SPACED FIBER TUFTS OF HIGH CONCENTRATION ARRAYED ON AT LEAST ONE SURFACE. THE TUFTS ARE COMPOSED OF A PLURALITY OF CLOSELY ASSOCIATED, SUBSTANTIALLY ALIGNED FIBERS ANCHORED WITHIN BUT EXTENDING FROM THE WEB BODY PORTION IN THE FORM OF WEFT-LIKE FIBER BUNDLES. THE NONWOVEN WEB MATERIAL IS PRODUCED BY A WET PAPERMAKING PROCESS THAT INCLUDES THE STEPS OF PROVIDING AN AQUEOUS FIBER DISPERSING MEDIUM HAVING A CONTROLLED FLUID VISCOSITY OF ABOUT 3 CENTIPOISES AND MORE DISPERSING WITHIN THE VISCOUS MEDIUM SELECT FIBERS HAVING A DENIER OF AT LEAST 1 D.P.F. AT A FIBER CONCENTRATION OF AT LEAST ABOUT .02 PERCENT BY WEIGHT AND DEPOSITING THE FIBERS WITHIN SAID DISPERSION ON AN APERTURED FIBER COLLECTING ELEMENT WHEREIN THE AVERAGE HOLE AREA OF THE APERTURES IS ABOUT 3X10**-4 SQ. IN. AND MORE TO FORM THE TUFTED NONWOVEN FIBROUS WEB WITH THE TUFTS FORMED BY BUNDLES OF SUBSTANTIALLY ALIGNED FIBERS EXTENDING THROUGH THE APERTURES.

Description

a. w. CONWAY ETAL 3,834,983 G WET LAID TUFTED NONWOVEN FIBROUS WEB FROM US FIBROUS DISPERSION AND PRODUCT 2 Sheets-$heet l A VISCO Sept. 10, 1974 PROCESS OF FORMIN Filed March 15, 1973 i W, a,

kzmimjm S t.'10, 1974 B. w. CONWAY ETAL 3,834,983

PROCESS OF FORMING WET LAID TUFTED NONWQVEN FIBROUS WEB FROM A VISCOUS FIBROUS DISPERSION AND PRODUCT piled March 15, 1973 2 Sheets-Sheet 2 United States Patent PROCESS OF FORMING WET LAID TUFTED NON- WOVEN FIBROUS WEB FROM A VISCOUS FIBROUS DISPERSION AND PRODUCT Bernard W. Conway, Holyoke, Mass., and James Moran, Simsbury, Conn., assignors to C. H. Dexter & Sons, Inc., Windsor Locks, Conn.

Filed Mar. 15, 1973, Ser. No. 341,699 Int. Cl. D21h 3/12, 3/40 US. Cl. 162-168 9 Claims ABSTRACT OF THE DISCLOSURE A tufted nonwoven waterlaid web material exhibiting high loft, bulk and absorbency is comprised of a substantially planar web body portion of randomly arranged water dispersible fibers and a multitude of separate, spaced fiber tufts of high concentration arrayed on at least one surface. The tufts are composed of a plurality of closely associated, substantially aligned fibers anchored within but extending from the web body portion in the form of weft-like fiber bundles. The nonwoven web material is produced by a wet papermaking process that includes the steps of providing an aqueous fiber dispersing medium having a controlled fluid viscosity of about 3 centipoises and more dispersing within the viscous medium select fibers having a denier of at least 1 d.p.f. at a fiber concentration of at least about .02 percent by weight and depositing the fibers within said dispersion on an apertured fiber collecting element wherein the average hole area of the apertures is about 3X10 sq. in. and more to form the tufted nonwoven fibrous web with the tufts formed by bundles of substantially aligned fibers extending through the apertures.

BACKGROUND AND SUMMARY OF THE- INVENTION The present invention relates generally to the production of tufted nonwoven fibrous web materials. More particularly, it is concerned with a new and improved wet paper-making technique for the production of tufted nonwoven materials exhibiting the appearance and characteristics of high loft absorbent bath toweling and the like.

As is well known, conventional wet paper-making techniques have traditionally produced compact, closely formed sheets exhibiting the rattle and smooth surface characteristic usually associated with paper. In recent years, increased emphasis has been placed on the production of nonwoven fabrics for apparel, household and industrial uses. Such fabrics, though initially produced as dry fibrous batts processed on textile carding equipment, I

now include certain wet-laid webs made on paper-making machines using techniques especially developed for the production of nonwoven materials. The materials thus produced exhibit textile-like characteristics including softness, drape and hand, and have found extensive use in the field of disposable fabrics.

Many of the non-woven fabrics produced heretofore have utilized a patterned configuration of one form or another in order to impart to the material the desirable characteristics of woven cloth. This patterned configuration has generally been achieved by subjecting a preformed web to controlled destructive forces which rearrange and reorient the fiber construction and provide a multitude of small apertures which improve the drape characteristics 1 of the resultant non-woven material. Typical examples of this fiber rearranging technique can be found in US. Pat. Nos. 2,862,251; 3,042,576 and 3,081,515.

Another technique for imparting some of the characteristics of woven fabrics to non-woven fibrous materials is the use of a needle punch operation that forms pegs 3,834,983 Patented Sept 10, 1974 of fibers which increase the structural integrity of the web while improving the flexibility and hand thereof. Still other techniques involve light surface brushing to provide a raised nappy surface exhibiting improved softness, for example in US. Pat. No. 3,101,520, or the use of electrostatic fiber flocking to achieve a comparable nappy surface. A further technique involves the utilization of a crepe or loop-forming operation either alone or in combination with a needle punch. The nonwoven fabrics containing the looped fibers tend to imitate the looped configuration characteristics of woven terry cloth and reportedly exhibit improved softness and high loft.

In substantially all of the foregoing processes it is necsasry to first form a web and then subject it to an additional structure altering treatment to provide the desired characteristics. Additionally, in many instances the initial nonwoven web materials are not produced in accordance with the more economical wet paper-making technique, thereby further adding to the cost of the finished product. Some progress has been made in producing patterned webs using a wet paper-making process and mention can be made of the dual wire technique disclosed in US. Pat. No. 3,322,617 and the techniques found in US. Pat No. 2,940,891.

Despite these previous attempts, it is believed that heretofore a wet paper-making technique has not been used to produce a tufted nonwoven toweling product having the loft, softness, bulk, absorbency and drape characteristics of Turkish toweling. A key factor in the inability of the prior art techniques to produce such materials has been the inability of the wet process to provide high loft materials having a high concentration of absorbent relatively loose and flexible yet sturdy fibers extending outwardly from the main body of the web.

Accordingly, it is an object of the present invention to provide a wet paper-making technique for producing high loft, tufty or tufted non-woven fibrous web materials exhibiting the softness, drape, hand, feel, bulk and absorbency associated with woven looped materials such as Turkish or terry toweling. Included in this object is the provision for a new and improved water-laid material exhibiting these characteristics.

Another object of the present invention is to provide a new and improved wet paper-making technique and resultant product which uniquely combines the advantageous features of the wet paper-making technology in a new and controlled manner to provide a product characterized by having on at least one surface thereof a multiplicity of fiber tufts or bundles extending outwardly from the continuous planar body portion of the product in the form of multiple strand fiber bundles exhibiting an appearance similar to a weft of hair or pigtail.

A further object is to provide a technique of the type described utilizing a viscous fiber suspending medium and a coarse fiber collecting paper forming element. Included in this object is the provision for a technique capable of using a wide variety of fibers including most conventional papermaking and textile fibers.

Other objects will be in part obvious and in part pointed out in more detail hereinafter.

These and related objects are accomplished in accordance with the present invention by providing a fibrous nonwoven water-laid web material exhibiting high loft, bulk and absorbency. The web is comprised of a substantially planar web body portion of randomly arranged water dispersible fibers and a multitude of separate, spaced fiber tufts of high concentration arrayed on at least one surface thereof. The tufts are composed of a plurality of closely associated, relatively independent, substantially aligned fibers anchored within but extending from the web body portion in the form of weft-like fiber bundles. The nonwoven web material is produced by a wet paper-making process that has been modified to include the steps of .providing an aqueous fiber-dispersing medium having a controlled fluid viscosity of about 3 centipoises and more, dispersing within the viscous medium select fibers having a size of at least 1 d.p.f. at a fiber concentration of at least about .02 percent by weight and depositing the fibers .within said dispersion on an apertured fiber collecting element wherein the average open area of the apertures .is about 3 10- in. and more to form the tufted nonwoven fibrous web with the tufts formed by bundles of closely associated, substantially aligned individual fibers extending through the apertures.

A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawing which set forth an illustrative embodiment and are indicative of the way in which the principles of the invention are employed.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF A PREFERRED EMBODIMENT The new and improved tufted nonwoven web material of the present invention is produced in accordance with the present invention by a papermaking operation characterized by its utilization of a coarse web forming member coupled with a viscosity controlled fiber dispersing medium. This technique results in a nonwoven material having a high concentration of separate fiber tufts or wefts extending from the surface of the web material at substantially a right angle thereto when formed. This tufted nonwoven material can be better visualized by first appreciating the structural configuration of both woven toweling and nonwoven looped and nappy web materials.

Turkish or terry toweling is a loosely woven fabric characterized by a nap comprised of a larger number of individual loops of thread projecting outwardly from the body of the fabric. These individual loops provide a pliable or yieldable cushion effect and readily bend or distort during use not only to give the soft feel of high bulk or loft, but also to expose greater thread surface area to perform the desired absorbing and wiping function.

Nonwoven high loft looped fabrics are somewhat similar but have a flexible adhesive base with fibers individually looped outwardly from the base and adhesively embedded in the base. The fabric can be formed by first producing a dry formed striated base web of substantially aligned fibers having fiber length of about 23 inches. The Web is then imprinted with a lattice-like pattern of adhesive and tensioned to retain the aligned fiber array. The adhesive is cured and the fibers in the web are looped by feeding the web to a gathering blade. 7

Heretofore, improved softness has been applied to textile fabrics by lightly brushing its surface to raise a fibrous n'ap or pile of individual fibers. This technique has also been apl-ied to nonwoven web material but frequently has resulted in a substantial loss. It has been reported that suitable bonding will retain the strength of the material while permitting thebrushed fibers to individually extend outwardly from the main body of the material to provide the desiredsoftness.

The tufted nonwoven high loft material of the present invention has a characteristic surface that differs substantially from either looped material or conventional Webs with a brushed on nappy surf-ace. Instead, as shown in FIGS. 3 and 4, it is characterized as having a large number and high concentration of separate fiber bundles or turfts that extend outwardly from the main fibrous body portion of the web. The multiple fibers in each tuft terminate in free fiber ends spaced at randomly different distances from the main fibrous body. Despite the random location of the free fiber ends, the tufts exhibit a somewhat tapered appearance much like a weft of hair in that they are firmly attached to the main body portion of the web and taper to their longest length near the center of the bundle or tuft. As best seen in FIG. 3, the long tufts will tend to exhibit a waviness along their length and will loosely rest on the surface of the web material. Since each tuft is composed of a plurality of closely collected or bundled fibers yet each fiber is substantially aligned and relatively independent of other fibers Within the tuft, the tufts exhibit substantial flexibility, pliability and softness while also imparting high loft, bulk and absorbency to the web material. Unlike pegs produced from needle punch operations the fibers within the tufts are not substantially bent or ruptured and the tuft does not exhibit a pronounced central void or hole. As will be understood from the following description, the number of fibers in each tuft and the concentration of the tufts will vary substantially depending on the operating conditions employed in producing the web material.

The fibers forming the tufts receive their projecting orientation during sheet formation by controlling a number of factors associated with the wet paper-making process. However, the principal factor involved in this technique in the production of suitable fluid dynamics within the system at the time the fibers are initially deposited on the fiber collecting structure and formed into the non- Woven Web.

While all factors associated with the fluid dynamics of the system are not fully understood due to their complex inter-relationships, it has been noted that best results are achieved by laminar flow through the paper forming ele ment under controlled fluid drainage conditions. The laminar flow apparently tends to orient the fi-bers into their perpendicular substantially aligned positions relative to the Web without at the same time causing the fibers to pass entirely through the collecting structure.

Two of the factors considered essential in achieving the optimum fluid conditions required for the tufted nonwoven product of the present invention are (1) the use of a relatively coarse paper forming element; such as a wire screen or apertured plate having thicker solid areas and larger open areas relative to a standard Fourdrinier paper forming Wire and (2) a controlled fluid viscosity in the fiber dispersion used in forming the nonwoven material. As will be appreciated, other factors interrelated to the aforementioned two essential characteristics will also alfect the formation of the desired tufted nonwoven material. These include inter alia, the consistency or fiber concentration of the dispersion, the vacuum used to effect removal of the dispersing medium, the type and composition of fibers employed as well as their denier and length and the basis weight of the resultant product.

As mentioned, one of the primary and necessary factors associated with the new and improved technique of the present invention is the utilization of fiber collecting or paper forming elements which are substantially coarser than those normally used in manfacturing papers having the basis weights exhibited by the products of the present invention. As is known, the standard Fourdrinier screens are typically fine wire members and have about 60-100 strands per inch in each direction with the strands having a thickness or diameter of about 0.006 inch. The screening elements used in accordance with the present invention are well below the typical 75 mesh of Fourdrinier screens and in fact, are about 45 mesh or less and preferably about 14 to 24 mesh. Additionally, the thickness of the solid areas is at least twice that of the Fourdrim'er screen and may be four or five times thicker or wider. Thus, suitably apertured plates or screens can be used with good results.

The coarse paper forming screens or wires such as the so-called cabled or twisted cable type or the more recent plastic screens are generally preferred. These have strand thicknesses of at least 0.012 inch and preferably in the range of .0l8.035 inch resulting in drainage openings generally having an average hole area about 2 to 60 times greater than the approximately 0.95 sq. in. area of the Fourdrinier screen openings. It will be appreciated that the exact screen type and size utilized will vary depending on the desired product, the type, denier and length of fiber used in the furnish, the consistency of the furnish as well as the viscosity of the suspending fluid and the amount of vacuum applied during web formation. Quite naturally, and in fact preferably, the open or coarse screens tend to result in an undulating web configuration and tuft waviness which also adds to size employed can vary substantially depending on the numerous other considerations relating to the process.

A second essential feature of the paper-making technique of the present invention involves the use of a viscous dispersing fluid for the fibers. That is, a dispersing fluid exhibiting a viscosity greater than that exhibited by water. The high viscosity advantageously permits the utilization of numerous fibers and mixtures thereof not heretofore used in a wet paper-making process, including mixtures of textile staple fibers with fibers having a substantially shorter length. The viscous solution used to disperse the fibers prevents the formation of fiber clumps within the dispersion and reduces the tendency of the dispersed fibers to entangle. Additionally, the dispersing medium maintains the fibers in their dispersed condition during drainage and assures a more uniform fiber distirbution within the resultant web material thereby contributing to the improved softness, flexibility and drape characteris TABLE I.-WEB FORMING SCREEN Average hole size Distance between Material Diameter (in.) wires (in (XAIZea;

Mesh size Warp Shute Warp Shute Warp Shute sq. in

Bronze Bronze- .021 .013 .0102 .0286 2. 91

Plastic.. P1astic 018 .015 .0236 .0266 6.27

do Stainless steeL 032 .019 0097 0366 3. 55

Bronze" Bronze- 024 019 .0176 0464 8. 16

- Plastic Plastic 030 025 0116 0464 5. 38

24-12 Bronze... Bronze .023 025 0186 0583 10. 84 Plastie Plastic 030 025 0325 0375 12. 18

Bronze Bronze. 030 020 0325 0510 16. 50

the apparent bulk and loft of the nonwoven material and is believed to impart improved hand, drape and appearance to the resultant product. The open, coarse configuration of the screen or plate permits greater laminar flow of the dispersing fluid through the apertures of the foraminous fiber collecting element during web formation so as to drive the fibers into the orientation required for producing the desired tufted configuration. At the same time, the size of the openings in the screen or plate should not be so great that the fibers within the fiber dispersion are not retained or hung-up on the screen during the web forming processes and the size of the solid areas should not be so great as to interfere with the drainage of the fiber dispersion. The precise size required is one which is large enough to provide the required fluid flow during drainage but small enough to permit the requisite fiber collection as the fiber dispersing medium passes rapidly through the screen.

It is an advantage of the present invention that a nonwoven or woven scrim or gauze may be used as the primary fiber collecting element. In that instance, the screen and the openings in the scrim would facilitate tuft formation while simultantously embedding the scrim in the nonwoven fibrous web deposited thereon. Such an arrangement would substantially strengthen the web without undue sacrifice in the softness of the tufted material.

As mentioned hereinbefore, the web forming element is preferably a screen of about mesh or less constructed of plastic strands or twisted cable wires. In accordance with the present invention, it has been found that screens having as few as 8 strands per inch and containing openings having an average hole area as much as sixty times larger than conventional web forming elements have been effectively employed. Although wires from different sources of supply will vary, a few typical exemplary wire sizes are set forth in Table I together with some of their physical characteristics. Generally, the size of the hole area will relate to the fiber diameter since the thicker fibers form tufts more effectively on the coarser, lower mesh screens. For most applications, an average hole area between 3 X 10- and 20 10 sq. in. is preferred although the exact extent of hole area or the exact screen tics of the material produced. In fact, the viscous medium of the present invention substantially expands the number and type of fibers that can be used. At present, only dispersions wherein all of the fibers are very short hard wood fibers are ineffective to provide a well tufted web. However, this is due primarily to the openness of the screen employed for the short fibers and is not full attributable to the viscosity of the dispersing medium. On the other hand, the dispersing medium will permit the utilization of percent natural, or synthetic paper-making or textile staple fibers or appropriate mixtures thereof.

As a general rule, the dispersing medium should exhibit a viscosity greater than about three centipoises. Although some tufting can be achieved even at this low viscosity level when other operating characteristics are appropriately controlled and where select fibers are employed, a viscosity greater than 10 centipoises is required for good results. Preferably, a viscosity level of 30 centipoises and more is used for best results. The viscosity actually utilized will vary and for practical applications can be as high as 250-300 centipoise. As will be appreciated, certain practical considerations will control the upper limit since extremely high viscosities may tend to interfere with the drainage characteristics of the system. Other practical limits relating to the runability of the paper-making machine include the vacuum available for removing the dispersing medium without disrupting the web, the extractability of the medium and the effect of its residual presence in the web as well as the economics associated with the system.

The viscosity controlling material may be a natural or synthetic material or blends thereof. However, the preferred viscosity controlling materials are the high molecular weight resins, such as the water soluble polymers formed from the polymerization of acrylamide. These polymers are preferably used since their dilute aqueous solutions can be easily controlled to provide the desired viscosity at the drainage area of the system, The preferred acrylamide polymer employed is a material sold by Dow Chemical Company under the trade name Separan AP-30. Other materials such as polyethylene oxide sold by Union Carbide Corporation under the name Polyox WSR 301 as well as selected viscosity producing carboxymethyl cellulose solutions can also be utilized. In addition, other conventionally employed materials that will produce controlled viscosity in aqueous solutions include water soluble synthetic polymeric electrolytes of methacrylic acid and copolymers thereof, as well as natural viscosity producing materials such as degradable enzymes, mixtures of natural and synthetic gums and inorganic salts. However, in accordance with the preferred embodiment of the invention, the viscosity controlling material should be one that is stable to shearing forces,

. can be added to the headbox and will maintain its viscosity up to and through the drainage area of the system.

As mentioned, the particular type of web forming element used and the specific viscosity employed for the dispersing medium will depend on other interrelated factors such as the type, denier and length of the fibers employed in the fiber dispersion. One of the particularly advantageous features of the present invention is the fact that tufted webs can be produced from a wide variety of natural and synthetic paper-making and textile fibers. For example, synthetic or manmade paper-making or textile staple fibers such as rayon, nylon, polyesters or vinyl polymers or copolymers can be used either alone or in combination with natural fibers such as bleached or unbleached Kraft, manila hemp, jute and similar papermaking fibers. Additionally, inorganic fibers such as glass, quartz, ceramic, mineral wool, asbestos and similar materials may also be employed in accordance with the teachings of the present invention.

The synthetic fibers may vary in both denier and length although the lower denier fibers are generally preferred. Fibers from about 1 or 1.5 denier per filament (d.p.f.) to about 15 d.p.f. and more have been successfully used and have produced excellent results. However, with the higher denier material it is generally necessary to use a lower fiber concentration and a more viscous dispersing medium. As will be appreciated the minimum and maximum denier employed will depend on many other related factors including the product requirements, machine operating conditions, consistency, screen size, etc.

The length of the synthetic fibers employed depends to a large degree upon the particular wire or screen used and will range from about A; of an inch or more up to several inches and can be of the straight cut-tow type used in papermaking operations or the crimped or straight textile staple fiber type. As mentioned, it is preferred to utilize the finer denier material having a length of about /2 to inch or more in order to impart to the material improved softness while retaining the desired loft and absorbency characteristics. However, mixtures using natural and synthetic papermaking fibers having lengths down to & inch or less may also be employed depending upon the particular properties and characteristics required in the final product.

In addition to the length and denier of the fibers employed, the fiber consistency or concentration in the dispcrsion prior to web formation requires appropriate control to facilitate formation of the tufted configuration. As a general rule, the lowest fiber concentration or consistency compatible with good release of the resulting product from the web forming wire is most desirable for best tuft formation. Accordingly, a fiber concentration ranging from about .02 percent to about 1.0 percent can be used, with the preferred range being about .05 percent to .5 percent fiber concentration. In standard laboratory operations a fiber concentration of about .1 percent has been found to produce consistently good results. The consistency on large papermaking machines will of course vary with machine conditions.

The fiber concentration and the viscosity of the dispersant will also affect the degree of vacuum or suction that must be applied to the underside of the paper forming element during web formation in order to provide the desired tufted effect. Although good tufting can be obtained under appropriate conditions even in the absence of vacuum, it is generally preferred that a vacuum be applied to the underside of the web forming wire as the fibers are deposited thereon in order to insure the appropriate fluid dynamics of the system. However, these variations will depend not only on fiber concentration and the viscosity of the dispering medium but also on on other factors associated with these systems such as the coarseness of the wire and the type and length of fiber utilized.

An additional factor for consideration when using the technique of the present invention is the weight of the material being produced. The technique described herein is capable of producing a tufted product at weights as low as about /2 ounce per square yard and even as low as /4 ounce per square yard. However, such light weight materials are only produced by very fine control over the other factors associated with the technique and the basis weight of most materials is at least one ounce per square yard or higher.

It can be appreciated that formation of the tufted configuration is initiated at the beginning of the web forming process and in fact it is believed that the tuft is the first portion of the web to be formed as the fibers are draped over the solid portion of the web forming element and are drawn through the intermediate opening due to the fluid dynamics of the system. This is depicted illustratively in FIG. 2. As the web gains thickness more fibers are deposited both in the tufts or bundles and within the body of the web until it reaches its described basis weight and strength. If the deposition of the fibers were terminated after only the original tuft formation, it would be noted that although a network of tufts was provided, the fibrous material exhibited very little strength, was substantially without sheet character and could not be removed from the web forming wire. Additionally, it has been noted that when the basis weight exceeds about 6 ounces per square yard few if any additionally deposited fibers take part in the tuft formation but merely form a mat on top of the tufted base with little or no fiber integration with the tufts.

Although the many factors mentioned hereinbefore are all interrelated in order to provide the desirable tufted configuration, it has been found that certain generalized guides can be stated. In this regard, it has been found that best results are achieved when using the highest possible fluid viscosity compatible with machine operation, the lowest fiber consistency compatible with good release from the web forming element and the lowest fiber denier acceptable in the product requirements. Ad ditionally, it has been found that longer fibers not only produce longer tufts but also aid release from the wire because of the stronger web produced. Additionally, it has been found that coarser wires give better tufts than fine wire configurations and that lower denier fibers give a better tufted product than higher denier fibers regardless of the length of the fibers employed. In this connection, and as mentioned hereinbefore, the higher denier fibers generally require a coarser wire and also require a higher viscosity and lower consistency than corresponding fibers of a finer denier. For example, a 1.5 d.p.f. fiber will provide an acceptable tufted product at a viscosity of 50 cps and a fiber concentration of about .2 percent, whereas comparable results can only be obtained with a 15 d.p.f. fiber at a viscosity of cps and a consistency of .1 percent. As will also be appreciated, the lower limit on the basis weight of the tufted product will vary with the coarseness of the wire employed, such that a lower basis weight material can be obtained with a finer forming Wire than with a coarser wire.

As shown the tufts are produced on one side of the material only and products exhibiting tufts on both sides can be readily formed by arranging tufted Web materials in back-to-back relationship. Interlocking of plies and the incorporation of strengthening or binding agents can be employed in a Conventional fashion either during or after web formation. Subsequent softening or other treatments may also be used.

EXAMPLE I A fiber dispersing medium having a viscosity of 150 cps was prepared as a .15 aqueous solution of a water soluble polyacrylamide (Separan AP-30). Sufficient /1 inch, 15 d.p.f. rayon staple fibers were added to the viscous medium to prepare a 0.1% fiber dispersion. The fiber dispersion was poured into a hand sheet mold fitted with a 24 x 16 mesh bronze cabled wire screen having an average hole area of 8.16 sq. in. and was drained with the assistance of a vacuum. The resultant fibrous product was an excellent tufted fabric web having a basis weight of 2.55 ounces per square yard.

EXAMPLE II Following the general procedure of Example I, a .1% fiber dispersion was prepared from /1 inch 1.5 denier rayon staple fibers dispersed in a polyacrylamide (Separan AP-30) solution having a viscosity of 50 cps. The fiber dispersion was poured into a hand sheet mold fitted with a 16 x 16 mesh polyester regular weave wire having openings with an average hole area of about 12.2 104 sq. in. Vacuum was applied to the underside of the wire and a nonwoven web material was produced having excellent tuft characteristics and a basis weight of about 2.55 ounces per square yard.

EXAMPLE III The procedure of Example II was repeated using a .05 fiber dispersion of 70% inch 1.5 denier rayon staple fibers and 30% Weyerhauser Kraft in a polyacrylamide (Separan AP-30) solution having a viscosity of 25 cps. The resultant web material exhibited excellent tuft characteristics at a basis weight of 2.4 ounces per square yard.

EXAMPLE IV A .12% fiber dispersion was prepared from /2 inch 1.5 denier rayon staple fiber dispersed in a karaya gum solution having a viscosity of 40 cps. The fiber dispersion was poured into a hand sheet mold fitted with the 16 x 16 mesh polyester wire of Example II and a vacuum was applied to the underside of the wire to aid in the removal of the dispersing medium. An excellent nonwoven tufted fabric was produced having a basis weight of 6.6 ounces per square yard.

EXAMPLE V A dispersion of inch 1.5 denier rayon staple fibers was prepared in an aqueous solution of a polyacrylamide (Separan AP-30) solution having a viscosity of 50 cps. and was fed into the head box of the papermaking machine at a fiber consistency of 0.2%. The machine was provided with an inclined 24 x 18 mesh bronze cabled wire having openings with an average hole area of about 6.78 10 sq. in. The dispersion was fed to the head box of the papermaking machine without change in viscosity and the drainage was assisted by vacuum. The resultant product was an excellent tufted fabric having a basis weight of 2.85 ounces per square yard.

The example was repeated using the 16 x 16 mesh polyester regular weave wire of Example II and also produced excellent tufted nonwoven web material.

EXAMPLE VI As an example of the increased viscosity required to produce tufted products when higher denier and less flexible fibers are employed, the fibers set forth below were dispersed in a solution having the viscosity indicated.

r 10 In each case, a tufted product was produced exhibiting excellent loft, drape and hand characteristics comparable to textile products. I

- Viscosity Length, Conc., Fiber Denier inch percent I cps.

1 Diameter in microns. 2 Demer per filament.

EXAMPLE VII The procedure of Example I was repeated using rayon staple fibers of 1.5 denier and inch length and nylon fibers of 3 denier and 1.5 inch length. In each case the resultant web material exhibited excellent tufted characteristics, with the longer nylon fibers producing tufts of substantially greater length than those produced by the shorter rayon fibers.

EXAMPLE VIII The procedure of Example I was repeated using rayon fibers 1.5 denier, inch length and a dispersion viscosity of 100 cps. The fiber consistency was .1% and sheets were prepared exhibiting excellent tufted characteristics and having basis weights in ounces per square yard of 0.6, 1.1, 1.7, 2.2, 2.6, 3.3, 3.8, 4.5, 6.9 and 9.0.

As mentioned hereinbefore, the tufted nonwoven web material of the present invention is particularly well suited for use in the manufacture of disposable items. These uses include not only wash cloths, wiping cloths, towels, cosmetic wipes, coverstock for diapers, santiary napkins and the like, blankets, dish cloths, bandages, dressings and other medical supplies, barbers neck bands, head rests, dust collector felts, dust cloths and mops and wiping cloths of all kinds but also wearing apparel such as disposable bathing suits and jackets, surgical masks, disposable cap and industrial and domestic clothing such as costumes and novelty clothing including interlining for clothing. It is anticipated that the nonwoven web material of the present invention may also be advantageously employed for disposable bibs, tray covers, placemats, facial tissue, disposable draperies, carpet backing and semidurable rugs, wall covering, insulating materials including cryogenic insulation, obstetrical sheets, sleeping bag liners, bed pad liners and covers, protective wrapping or as substrates for a coating of a fabric softening composi tion. The web material might also be employed as a filter material for either air or fluid, such as coffee filters or infusion web materials such as tea bags, and if suitably treated could be used as a coating substrate for various items such as a substrate for synthetic leather or as a substitute for buckram interliners. As will be appreciated, laminated structures could also be formed from the nonwoven web material of the present invention including laminates for reinforced layers of plastic film, laminated or molded papers, light diffusers, lampshades or decorative sliding door paper or the material could be used in cordage, stretchable bags or sacks or for use in the upholstery for home furnishings and automobiles. As will be appreciated, the foregoing list of uses is not intended to be exhaustive but is merely exemplary of the versatility of the material produced in accordance with the present lnvention.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

We claim:

1. A process for producing a tufted nonwoven waterlaid fibrous web material comprising the steps of providing an aqueous fiber dispersing medium having a controlled fluid viscosity of about 3 cps. and more and an T1 1 apertured fiber collecting element wherein the average hole areaof the apertures .isv at least about twicethe 0.95 sq. in. area of the apertures in a Fourdrinier wire; dispersing within the viscousmedium suflicient water 'dispersible fibers to provide a fiber concentration of at.

least about.02 percent by weight and depositing the fibers from said dispersion on the fiber collecting element to form a tufted nonwoven fibrous web with the tufts formed from bundles of closely associated individual fibers extending through the apertures in said element.

2. The process of claim 1 wherein the fiber collecting element is provided with apertures of a size comparable to a screen having a mesh size in the range of about 8-45 and the viscous fiber dispersing medium has a viscosity greaterthan 3 cps.

3. The process of claim 1 wherein the fiber collecting element is a screen of about 14 to 24 mesh and the average hole area of the openings in the screen are in the range of 3 X 10' to 20X 10- sq. in.

4. The process of claim 1 wherein the viscous fiber dispersing medium has a viscosity of at least 10 cps. up to about 300 cps.

5. The process of claim 1 wherein the fiber dispersing medium is an aqueous resin solution and the water dispersible fibers include synthetic fibers of about at least 1.0 d.p.f. and a length in the range of about A; inch up to 1 inch and more.

6. The process of claim 1 .wherein the fiber concentration is in the range of 0.05% to 0.5%.

7. The process of claim 1 wherein the fiber dispersing ,medium has a viscosity of at least about, cpsand removal of the dispersing medium from the collecting element. as the fibers are deposited thereon. is. vacuum assisted. g T

8. A product made by the process of claim 1. 9. A product made by the process of claim 5.

References Cited S. LEON BASHORE, Primary Examiner W. F. SMITH, Assistant Examiner U.S. cl. X.R.

16162; l62116, 146, 157 R, 157 c, 158, Dig. 2

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 834,983 Dated September 10, 1974 Inventor(s) Bernard W. Conway and James Moran It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, lines 13 'and l4, the word "nec-sasry" should 'be "necessary".

Column 3, line 67, the word "aplied" should be applied".

Column 3, line 68, the word "strength" has-been omitted after the word 'substantial".

Column 4, line 46, the word "flow" has been omitted after the Word "fluid".

Column 8; lines 8 and 9, the word "on" has been repeated.

Column 10, at the table, under the denier column, the last two numbers should have a subscript of "2" not "1".

Signed and sealed this 3rd day' of December 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents F ORM PO-1050 (10-69) USCOMM-DC GONG-P60 u.s. GOVERNMENT PRINTING ornc: In" 0-366-334.

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