FI59626B - SAETT ATT FRAMSTAELLA ETT TUFTAT ICKEVAEVT FIBROEST BANMATERIAL - Google Patents

Description

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Patani och regirtarstyralMn '1 Am »Icm utkgd od> uti.tkHfun pubimnd 29.05.81

(32) (33) (31) Fyydtttjr «cuaJk« i «—Begird priorityM 17.07.7U

USA (US) U89U11 (71) The Dexter Corporation, One Elm Street, Windsor Locks, Conn., USA (72) Bernard William Conway, Holyoke, Mass., James Moran, Simsbury, Conn., USA (7 ^) 0y Roister Ab (5 * 0 Method for making a fluffy, non-woven, fibrous web material - Sätt att framställa ett tuftat, icke-vävt fibrous ban-material

The invention relates to a method for producing a fluffy, non-woven fibrous web material, comprising placing a liquid dispersion of fibers on a fiber collecting element with apertures and providing a laminar flow of fiber dispersant through the openings. bundles of fibers extending.

Conventional, wet-laid papermaking methods are known to traditionally produce dense, tightly compressed sheets with the crispness and smoothness commonly associated with paper. In recent years, there has been an increasing increase in the use of non-woven fabrics for clothing, household and industrial purposes, the so-called manufacture of nonwovens. Such fabrics, although originally made into textile carding machines, now include some webs made on paper machines for nonwoven materials using specially developed methods. The materials thus produced, which have textile-like properties including softness, settlability and feel, have found widespread use in the field of disposable fabrics.

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Many nonwovens fabricated to date have had a patterned or other structure to impart advantageous properties to the material of the woven fabric. This patterned structure is usually accomplished by subjecting the preformed web to controlled disintegration stresses that rearrange and reorient the fibrous structure and provide numerous small holes that improve the fabric-like descent of the resulting nonwoven material. Typical examples of this method of fiber rearrangement are described in U.S. Patents 2,862,251; 3 0U2 576 and 3 08l 515.

Another way to give nonwoven fibrous materials some of the properties of woven fabrics is to use a needling method to form pegs of fibers ("pegs") that increase the structural integrity of the web while improving its flexibility and feel. Yet another method is to lightly surface brush to provide an embossed, higher softness lint surface, as described, for example, in U.S. Patent 3,101,520, or to use an electrostatic fibrous support to obtain a similar lint surface. Another way is to use a creping or looping method alone or in combination with a needle. Nonwoven fabrics containing spliced fibers tend to mimic the loop structure characteristic of a woven terry and are explained to have improved softness and very high porosity.

In essentially all of the prior art methods, it is necessary to first form the web and then subject it to further structurally modifying treatment to provide the desired properties. Moreover, in many cases, first, nonwoven web materials are not produced by a more economical wet papermaking method, which further increases the cost of the final product. Some progress has been made in the production of patterned webs using the wet papermaking method. In this regard, reference is made to the two-wire method of U.S. Patent 3,322,617 and the methods of U.S. Patent 2,919,091.

Despite these previous attempts, it has been shown that wet papermaking methods have not been successfully used to make fluff-woven nonwoven fabric products having terry porosity, softness, fluff, absorbency, and settability. The main reason why previous methods have not been able to produce such materials has been the inability of these methods to wet produce porous materials with a large relative amount of absorbent, relatively loose and flexible but strong fibers exiting the web body. However, a leap in this direction has taken place according to U.S. Patent No. 3,838,983.

In the method according to said patent, the formation of fiber webs is performed at the same time as the web itself is formed. This is achieved by using a viscous fiber dispersant and a stiff web-forming fabric. Although good fluff formation of 3,59626 is obtained using a wire of the type described, there has been some entanglement or entanglement of the free ends of the fiber fluff prior to removal of the web from the wire. This entanglement not only has an adverse effect on the appearance of the product, but also makes it difficult to remove the web from the web-forming wire.

It is therefore an object of the present invention to provide an improvement to the process disclosed in said U.S. patent and, more particularly, to provide an improved wet path fabrication process for producing highly porous, fluffed nonwoven fibrous web materials having woven, looped materials such as terrycloth, feeling, puffiness and absorbency.

More specifically, the invention is essentially characterized by the use of a fiber assembly element formed by a plate-like element having a smooth fiber assembly surface and a plurality of holes extending substantially tubularly through the element to prevent the lint extends through the element, and that the fluff is compressed while located in the holes to form compressed fluff on the surface of the web material.

The invention will be explained in more detail below with reference to the accompanying drawings, in which Fig. 1 is a flow chart of general steps used to produce a new and improved web material according to the invention, Fig. 2 is a perspective view of a manual sheet former forming sheet, Fig. 3 is an enlarged sectional view Fig. 1+ is a 5x magnified photograph showing the surface of a web material made by the method of the invention, and Fig. 5 is a schematic view illustrating features of the invention on both sides of a sheet material; on a plate, a flat-faced web, a compression jet and a support net used in one embodiment of the invention are shown. .

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The new and improved nonwoven web material of the invention is prepared, as mentioned, according to a papermaking process similar to that described in U.S. Patent No. 3,838,983, which is thus exemplified by the prior art. Using this method, a nonwoven material is obtained which has a large number of discrete bundles of fibers which may be in the form of compressed fiber workpieces formed on at least one, preferably both, surfaces of the web material. A better picture of such a fluffed material can potentially be obtained by first finding out the structure of both woven towel fabrics and non-woven, looped and fluffy web materials.

Terry cloth fabric is a loosely woven fabric characterized by a pile consisting of a plurality of discrete yarn loops projecting from the base fabric. These individual loops form a flexible or trailing surface structure and bend or turn easily in use, not only to give a fine feel due to high fluff or porosity, but also to expose a larger wire surface area for the desired suction imaging function.

The nonwoven, highly porous looped material resembles its woven counterpart to some extent, but has a flexible adhesive base with fibers, each looped outward and adhesively embedded in the base. A nonwoven fabric of this type can be formed by first making a grooved base web from substantially parallel fibers of about 50 to 80 mm in length. A web made by the "dry" forming method is then printed with a mesh pattern of adhesive and stretched to maintain a parallel fiber orientation. The adhesive is cured and the web fibers are looped by feeding the web to a looper.

It has been the custom to give textile fabrics greater softness by light surface brushing to provide a fibrous pile from the individual fibers. This method has also been applied to nonwoven web material, but has often resulted in a significant reduction in strength. It will be appreciated that suitable bonding maintains the strength of the material while allowing the brushed individual fibers to protrude from the body of the material to impart the desired softness to the material.

The fluff-surfaced, nonwoven, highly porous material made according to the invention does not have a looped, brushed or cut pile surface thus formed. Instead, it is characterized, as shown in Figure U, by a large number and a large proportion of discrete bundles or tufts of fibers which extend outwards from the larger, fibrous body part of the web and completely cover its planar surfaces. The numerous fibers of each plume 5,596,26 may terminate in free ends that are initially randomly spaced at different distances from the larger fiber body or base. Despite the random location of the free ends of the fibers, the fluff, when initially formed, has a slightly conical appearance that greatly resembles a weft because the fluff is firmly attached to the web body and tapers upon reaching its full length near the center of the fluff. If the long feathers are not compressed, they tend to ripple in their longitudinal direction and rest loosely on the surface of the web material. Each feather is composed of a plurality of densely collected or bundled fibers, however, each fiber being substantially rectilinear and relatively independent of the other fibers in the feather. This results in the feathers being quite flexible, flexible and soft. While still located on the forming element, the tufts have a funnel-like shape which tends to disappear when the web is removed from the forming element. The fluffs can be compacted, i.e. compressed, during manufacture into a puff-roll or "puff" shape, which also gives the web material a high degree of porosity, fluff and absorbency. Unlike pegs, the fibers of the fluff are not significantly damaged or detached during the formation of the fluff. In addition, as will be apparent from the following, the number of fibers in the webs and the relative number of webs will vary considerably depending on the conditions of use used in the manufacture of the web material.

The fluff-forming fibers acquire their protruding orientation during sheet formation by regulating a few factors associated with wet-road papermaking. However, a key factor in this method is to provide suitable fluid dynamics to the system at the time the fibers are first deposited on the fiber assembly structure and formed into a nonwoven web, a fibrous mat.

Although not all factors related to the fluid dynamics of the system have been fully elucidated due to their complex interrelationship, it is assumed that the best results can be obtained by laminar flow through the papermaking element by controlling the dewatering conditions. The laminar flow apparently tends to orient the fibers in their first, substantially rectilinear orientation perpendicular to the web body without simultaneously causing the fibers to pass completely through the assembled structure. In fact, the fibers extending through the holes of the forming element accumulate on the side walls of each hole and adhere to the element, thus favoring laminar flow through the centers of each hole or near the axis.

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Two of the factors considered in U.S. Patent Application No. 341 * 699 to be essential for achieving the optimal fluid flow conditions required for a fluffy, nonwoven product are (1) the use of a relatively coarse papermaking element and (2) the controlled fluid viscosity to form the nonwoven material to be used. However, according to the invention, it has been shown that the type of web shape support element, in particular the shape and surface structure, is a major factor in the efficient formation of fluff. As will be appreciated, other factors which are interrelated with the above factors also affect the production of the desired non-woven material with a vacuum surface. Which factors include e.g. the consistency of the dispersion, i.e. the fiber content, the vacuum used to remove the dispersing medium, the type and composition of the fibers used, as well as the denier and length of the fibers and the bulk coating of the product obtained. In fact, according to the invention, it has been found that the use of a suitable board and thinner wood pulp fibers allows the formation of tufted webs in a system which eliminates the need for a viscous dispersant.

Thus, the primary and necessary elements of the new and improved process of the invention are the use of a fiber assembly or papermaking element which is plate-like in nature and which in certain applications is thicker than the elements normally used in the manufacture of light and medium-heavy papers. As is known, the standard wires conventionally used in papermaking are usually woven, fine mesh elements having about 24-39 yarns / cm in each direction with a yarn thickness of about 0.013 mm. The mesh elements in said US patent application are very coarse woven nets with a free loop size of about 0.35 mm or less, mainly about 0.73-1 * 41 mm. Although satisfactory fluff formation has been achieved with such nets, it has been shown that the resulting fluff tends to adhere below the coarse web and become entangled with each other and the coarse web, which prevented the removal of the fluff-surfaced web from the forming element. It is assumed that the curved bottom surfaces of the wires and their tissue effect tend to promote entanglement.

According to the invention it has been found that the individual töyhdöt, thus projecting from the base layer of fiber bundles, can be kept separate from each other prior to use of the forming element forming the removal of the plate-like element instead of an element which exhibits a tissue effect which allows the wet adhering the fibers to wrap around the underside of the element. As can be seen, the thickness of the board varies due to factors such as the fibers used

Depending on the length of the yen. Plates about 0.8 mm thick have given good results, but plates about 6 mm thick and thicker, preferably about 12 mm thick are preferred in the manufacture of many Tainos. The thicker forming element tends to keep most of the fluff inside the individual holes of the element and facilitates compaction of the fluff if desired. Since only a small portion, if any, of each protrusion extends beyond the lower surface of these forming elements, there is little resistance to removal of the web. It has been found that the exact type and size of the forming element used will vary with the hole size and the desired product, as well as the type, thickness and length of fiber used in the pulp, the fiber content of the stock and the viscosity of the suspension liquid.

Figures 2 and 3 show a web forming element 10 for a manual sheet former used in an embodiment of the invention. The element 10 is a relatively thick plate-like element with spherical edges 12 and a web forming region 14 having a plurality of fluff forming holes 16 extending through the plate 10 and arranged in non-zigzag rows as shown in Figure 2, the hole spacing being adjusted as needed. For example, a plate having a thickness of about 12 mm and a central region diameter of about 70 mm may suitably have 19 holes / cm, with a hole diameter of 1.6 mm. The open area of such a plate is 37> 2. The plate 10 has substantially flat and smooth upper and lower surfaces 18 and 20 in the forming area 14.

It turns out that the factors regulating the plate include the prevention of tangle entanglement along with the maintenance of laminar flow.

Thus, a thin plate capable of producing a so-called "pipe flow effect" through its holes and at the same time avoid entanglement. This includes the ability of the forming element to provide a so-called "mouth or lip effect" sec! on the upper and lower surfaces. The flat upper and lower surfaces of the lvvy must therefore have relatively well-defined large edges, i.e. the so-called lips in each hole. A small degree of curvature can be allowed, in which case the edge of the bottom surface, i.e. the edge, turns out to be more critical. The lip action, together with the tubular, multi-hole shape, allows a laminar flow of dispersing fluid through the sheet during web formation to direct the fibers in the direction required to produce the desired, fluffy structure. As the fibers flow downward in these holes, they tend to adhere to the side walls of the holes, forming a fiber hopper that promotes tubular flow. If the walls of the holes do not join the lower surface of the plate with a large radius of curvature *, they tend to stick less to the lower surface of the element and thus less likely to become entangled. The size of the holes in the plate must be adjusted to 8 59626 so that the fibers of the dispersion remain in the web formation stage. At the same time, however, the extent of the solid surface must not be so large as to interfere with the drying of the fiber dispersion. The exact hole size and the entire portion of the hole portion must be such as to provide the required fluid flow during drying (dewatering) while the fibers can accumulate to the required extent as the dispersant fluid rapidly flows through the perforated plate. In one embodiment, the 12 mm thick plate has holes with a diameter of about 1.6 mm and are arranged in 2.3 mm increments in zigzag rows, as shown in Figure 2.

The web-forming element may be a laminate structure, but is preferably a sheet with four or more holes / cm, preferably about 16-78 holes / cm. The holes may be arranged in the zigzag pattern shown or other suitable patterns and may vary in diameter from about 0.8 to 4.8 mm.

The size of the open area depends mainly on the diameter of the fibers of the dispersion, because the thicker fibers more efficiently form fluff in their more open plates. In most applications, an average open area of about 13 to 50 is preferred, although the exact proportion of open area and the thickness of the sheet used can vary considerably depending on many other papermaking factors, especially the size of the fibers.

An advantage of the invention is that a non-woven or woven mesh or gauze or multiple continuous filaments can be used in connection with the primary fiber assembly element. In this case, the net moves with the support element and the openings of the net, i.e. the eyes, facilitate the formation of feathers as the net simultaneously sinks into the nonwoven fibrous web deposited on it. Such an arrangement considerably strengthens the web excessively without reducing the softness of the tufted material.

In the papermaking process according to the invention, a dispersing liquid having a controlled viscosity which varies with the viscosity of water, i.e. 1 cP, above depending on the plate and the fibers used in the system. The high viscosity medium advantageously allows the use of a large number of fibers and mixtures thereof which have not previously been used in a wet papermaking process, including mixtures in which textile staple fibers are blended with rather shorter fibers. The viscous solution used to disperse the fibers prevents the formation of fiber clumps in the dispersion and reduces the tendency of the dispersed fibers to stick. In addition, the dispersing medium keeps the 9,59626 fibers in a dispersed state during drying and ensures a more even fiber distribution in the resulting web material, which helps to give the finished material improved softness, flexibility and settability.

As mentioned, the viscous medium greatly increases the number and type of fibers available, while the board allows the use of aqueous dispersions in which all the fibers are very short, fibers from hard wood species. This is thought to be primarily due to said lip action and laminar flow, tubular flow, through the sheets used in short fibers, even in the absence of viscosity-increasing additives in the dispersant. The invention thus makes it possible to form fibrous webs even when 100 Estonian natural or synthetic papermaking or textile staple fibers or suitable mixtures thereof are used.

As a general rule, the viscosity of the dispersant should be greater than about 3 cP if longer fibers are used than conventional wood pulp fibers. Although fluffing can be achieved at low viscosities when other operating conditions are appropriately controlled and when selected fibers are used, a viscosity of about 10 cP or greater is preferred. The viscosity actually used varies and can be as low as 1 cP or as high as 25Ο-3ΟΟ cP in practical applications. As can be seen, certain practical conditions regulate the upper limit, as extremely high viscosities may tend to interfere with the drying properties (dewatering) of the system. Other practical limitations associated with paper machine performance include the available vacuum to remove the dispersing medium without breaking and interfering with the fiber content of the medium, the extractability of the medium and the effect of the portion remaining on the web, and the economy of the system.

The viscosity regulating agent may be a natural or artificial substance or a mixture thereof. However, the preferred viscosity regulating agent is a high molecular weight resin, such as an aqueous polymer prepared by polymerizing acrylamide. This polymer is preferably used because its dilute aqueous solutions can be readily controlled to provide the desired viscosity to the drying zone of the system. The preferred used acrylamide polymer is sold by Dow Chemical Company under the tradename Separan AP-30. Other materials may also be used, such as polyethylene oxide sold by Union Carbide Corporation under the name Polyox WSR 301, as well as selected viscosity-increasing carboxymethylcellulose solutions. Some commonly used materials that provide controlled viscosity to aqueous solutions include ίο 5 9 6 2 6 water-soluble synthetic polymeric electrolytes of methacrylic acid and its copolymers, as well as viscosity-enhancing natural and degradable enzymes, mixtures of natural and synthetic gums. However, according to a preferred embodiment of the invention, the viscosity control agent must be such that it can be added before web formation, such as to a fiber dispersing device, headbox, etc., and that it retains its viscosity up to and through the drying zone of the system.

As mentioned, the specific type of web-forming element and the specific viscosity of the dispersing medium depend on other interrelated factors, such as the type, thickness and length of the fibers used in the dispersion. A particularly advantageous feature of the invention is that fluffy webs® can be made from a variety of natural and synthetic papermaking and textile fibers. For example, synthetic papermaking or textile staple fibers such as rayon, nylon, polyesters or vinyl polymers or copolymers may be used alone or in combination with natural fibers such as bleached or unbleached sulphate cellulose fibers, manila fibers, jute fibers and jute fibers. In addition, it is contemplated that inorganic fibers such as glass fibers, quartz fibers, ceramic fibers, mineral wool fibers, asbestos fibers, and the like may be used in accordance with the invention.

Synthetic fibers can vary in both thickness, denier, and length, although low-density fibers are generally considered more suitable. Fibers having a denier of about 1 or 1.5 / filament (dpf) to about 13 dpf and greater have been used successfully with excellent results. However, when using high strength fibers, it is usually necessary to use a lower fiber content and a higher viscosity dispersant. The minimum and maximum dimers used are due to many other related factors, including product requirements, machine operating conditions, concentration, plate size, etc.

The length of the synthetic fibers used depends greatly on the particular forming element used and varies from about 3 mm to hundreds of mm, and the fibers may be of the straight cut fiber type 1 or the curled or straight textile staple fiber type used in the papermaking process. As mentioned, it is preferred to use a low grain fiber material - with a fiber length of about 12-19 mm or greater - to make the material softer while maintaining the desired porosity and absorption properties. However, mixtures with natural or synthetic papermaking fibers as short as 1.6 or less in length can also be used, depending on the specific properties and nature desired for the final product.

In addition to the length and denier of the fibers used, the fiber content of the dispersion prior to web formation requires appropriate adjustment to facilitate the formation of the fluffy surface structure. In general, the lowest fiber content that still allows the resulting product to be easily detached from the web-forming element is most suitable for the best fluff formation. Thus, about 0.01-1.0%, preferably 0.05-0.5% fiber content can be used. In normal laboratory methods, a fiber content of about 0.2% has been shown to give the best results. The concentration in the paper machine will, of course, vary depending on the conditions of the machine.

The fiber content and viscosity of the dispersant also affect the degree of vacuum or suction that can be developed below the papermaking element during web formation to obtain the desired fluff formation effect. Although good fluff formation can be achieved under suitable conditions, even without vacuum, it is usually advantageous to develop a low vacuum below the web forming wire, corresponding to about 2 x 10 kp / cm, to ensure proper dynamics of the system fluid as fibers precipitate on the wire. In some cases, a higher vacuum may be developed, such as about 0.1 kp / cm. However, these changes do not only depend on the fiber content and the viscosity of the dispersant, but also on other factors related to these systems, such as the uniformity of the surface of the forming element, the hole size and the mouth or so-called the shape of the lips and the type and length of fiber used. Comparable effects can be obtained by applying an overpressure to the top surface of the web, provided that a suitable pressure difference is created across the web and the plate.

Another factor to consider when using the method according to the invention is the mass of the material to be produced. The method described here can be used to produce a fluffy surface product with a pulp margin as low as 17 g / m 2. However, such lightweight materials are obtained only by fine-tuning other process-related factors and the bulk coverage of most materials is at least 3 g / m 2.

It is clear that the formation of the fluff surface begins at the initial stage of the web-forming process, and in fact it is believed that the fibrous webs are the part of the web first formed when the fibers are applied to the closed portion of the web-forming plate and pulled through the plate holes due to system fluid dynamics. As the web thickens and thickens, more fibers 12,59626 accumulate, partly in funnel-shaped bundles, and in part in the web, until the web reaches its desired mass coverage and strength. It should be noted that the funnel-shaped shape of the fibrous web increases its flexibility, elasticity and softness due to the inherent cushion effect.

One feature of the invention is, as mentioned, that the feathers, i. protruding fiber bundles, need not have a hexagonal appearance, but may advantageously be intertwined, i. spherical fiber bundles similar in appearance to a French knot. The tensile strength of these webs has been improved up to 100%. Such a swirling fluff surface is best seen in Figure U, where the fluff is clearly seen in the form of spherical fiber bundles, the appearance of which reflects their softness, flexibility and yieldability.

Figure 3 shows one way to form this collapsed plume structure. In this method, the fluffy web is treated with a gas or liquid jet or similar compression force applied below the forming element, e.g. through a nozzle 26, before it is removed from the forming element.

A support wire, such as a mesh 28, may be placed on the top surface of the web to prevent unwanted movement of the web from the plate 10. As will be appreciated, the compressive force is applied only to the fibrous webs because the web portions between them are covered by the plate. The force may be a high velocity flow of liquid or air in the form of a jet directed upwards from below the forming element. The support net tends to keep the entangled fluff in its forming state, especially at the top thereof, so that the web can be removed from the perforated plate without hindrance and easily.

If desired, the web may be subjected to other post-forming treatments before or after its removal from the plate and either before or after conventional drying. For example, the adhesive can be applied only to the lint-free or non-lint-free surface in the form of a liquid or spray while the web is on the plate or after its removal. The bonding can also take place with heat, which activates the heat-binding fibers of the web.

Although said factors are arranged together to provide the desired fluffy structure, it has been shown that certain general guidelines can be set. Thus, it has been found that the best results are obtained by using a web-forming element with a flat surface and well-defined holes, a minimum fiber content suitable for good detachment from the web-forming element and a minimum fiber nib that is acceptable considering the product requirements. Furthermore, it has been shown that longer fibers not only form longer fiber bundles, but also create more cushioning and strength in dense feathers. In addition, it has been found that lower terrain fibers give a better fluffy surface product than higher terrain fibers regardless of the length of the fibers. As mentioned above, high-strength fibers, i.e., thick fibers, usually require a large-hole forming element, as well as a higher viscosity and a lower concentration than the corresponding lower-strength fibers. For example, a 1.5 dpf fiber gives an acceptable fluffy product at a viscosity of 12 cP and a fiber content of about 0.2%, whereas comparable results can only be obtained with a 15 dpf fiber at a viscosity of 150 cP and a concentration of 0.1%.

The use of a perforated forming element facilitates the production of webs with fluffy surfaces on both sides, as well as other modifications.

As shown in Fig. 5, the fiber dispersion can be fed to a headbox Uo with a double outlet trough b2 and a second central feed trough UL for feeding the mesh insert or several continuous filaments (monofilament yarns) from the sides U6. The fibers and filaments enter the gap area H8 between the two rotating drums 50 from the headbox. The drums have opposite perforated plates 52 with a thickness of about 12 mm. The drums rotate at opposite speeds in opposite directions, as indicated by the arrows, so that their surfaces move uniformly through the nip region U8. As can be seen, a low vacuum 5 * + suction box can be used in both drums to help with the fluid dynamics of the system. Good results have been obtained using a low vacuum of about 2 x 10 kp / cm. If desired, a large vacuum suction box 56 can also be used with the suction boxes 5b to be positioned to assist in the removal of the dispersing medium. Inside each drum, fluid jet nozzles 58 are installed in the vicinity of the suction box 56 to seal the fiber plugs prior to their separation from the perforated surfaces of the drums.

The invention is further illustrated by the following non-limiting examples.

Example 1 A web-faced web was prepared in a manual sheet former equipped with a perforated web forming plate about 12 mm thick. The plate was a circular plate, substantially as shown in Figures 2 and 3, and had a flat surface 100 mm in diameter and a perforated perimeter delimiting a perforated area of 70 mm in diameter. The holes here were 1.59 mm in diameter and went completely through the plate perpendicular to its surface.

The holes were arranged in zigzag rows, with the distance between adjacent holes being 2.3 mm, so that about 19 holes / cm entered the web-forming area.

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The fiber tea dispersion was prepared from 10 mm long rayon viscose fibers, 1.5 dpf, in a 0.04 # aqueous solution of polyacrylamide (Separan AP-30), viscosity about 12 cP. Sufficient fibers were added to the solution to give a concentration of 0.2 by mass.

* 2 2 Using a vacuum of 2 x 10 kp / cm, a web was formed from the fiber dispersion on a perforated plate. Here, there was a good fluff surface and the fluff (protruding fiber bundles) did not extend below the bottom of the plate, so the web could well be removed from the plate. The pulp margin (surface mass) was 169 .mu.g / m.

The procedure described above was successfully repeated by reducing the fiber content to 0.1-6 and without applying vacuum in drying. However, the increase in viscosity to 45 cP together with a vacuum of 0.1 kp / cin resulted in most cases in the fibers being drawn through the sheet, resulting in little or no web formation. Example 2

The procedure of Example 1 was repeated except that the fiber tea dispersion was prepared from polyester staple fiber, 16 dpf and length 19 mm, in a $ 0.32 aqueous solution of polyacrylamide (Separan AP-30) having a viscosity of about 400 cP. The fiber content was 0.1 pulp. A vacuum of 0.26 kp / cm was used and the resulting web had good fluff formation without entanglement of adjacent fluff even when the fluff extended below the plate.

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The rich pulp margin was 254 g / m 2.

The procedure was repeated except that the fiber tea dispersion was prepared from a blend of $ 70 polyester staple fiber and 30% Weyerhauser SG sulfate pulp. The mass coverage of the obtained web was 254 g / m and it also had a good fluff formation ·

Example 5

The procedure of Example 1 was repeated using the same web-forming sheet, but the fiber road dispersion was prepared from 1.5 dpf viscose staple fiber, 12 mm long, and the dispersant was a 0.25 aqueous solution of polyacrylamide (Separan AP-30) having a viscosity of about 220 cP. The fiber content used was 0.1 pulp- $.

2 Using a vacuum of 0.26 kp / cm, a web with a mass coverage of 2,340 g / m was formed, thus obtaining a high degree of work formation, excellent porosity, fluff and feel. The web of the feather surface was slightly better than the web of Example 1 due to the stubbornness and clarity of the feathers.

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Example 4

The procedure of Example 1 was repeated, but after removal from the forming element a, the web was treated on its airless side by spraying it with 0.15 l of an acrylic polymer latex solution. The latex emulsion used was an amide-crosslinked carboxylated ethyl acrylate prepared by Union Carbide Co. sold under the name UCAfi 874. After the latex was sprayed onto the web, it was dried and cured in a steam-heated tumble dryer at about 140 ° C. The amount of latex applied to the web was $ 5 based on the dry fiber mass. Because the fluffed fibers were attached to the flat body or bottom of the web, the fillings anchored more strongly while the fluffy surface part became soft and flexible.

Example 5

The procedure of Example 1 was repeated except that the fiber content was kept at 0.5% by mass and the vacuum used was 0.05 kp / cm 2. In this way 6 6 webs with a pulp cover of about 220 g / m 3 were prepared, whereby 5 webs were subjected to compacting the fluffs by the opposite liquid flow treatment while they were still on the forming plate. Using a 5.8 mm diameter water jet at a pressure of 5 * 6 kp / cm, which gave a jet speed of about 30 m / s, the water was directed against the underside of the web forming plate. 15 sprays were performed through each hole and the web was easily removed from the plate and dried. A strip 25 mm wide was cut from each of the 6 webs and tested for strength with a Scott Tensile Tester, model X5 * The average untreated tensile strength (dry) of the three untreated reference webs was 56.3 g / cm, while that of the tufted doughs was 127 g / cm. . The compaction of the tufts thus led to a considerable improvement in the tensile strength of the webs.

Example 6

The procedure of Example 5 was repeated except that the fiber content of the dispersion was 0.05 mass # and a vacuum of 0.03 kp / cm was used in the first formation of the doughs. Compaction of the feathers into spherical bundles like French knots was achieved at a lower pressure, i.

2.8 kp / cm, using a 0.36 mm jet of liquid passed 15 times into each of the 2 holes. The pressure of 2.8 kp / cm caused a speed of about 15-16 m / s for the shower. Example 7

A fiber dispersion having a fiber content of 0.13 pulp was prepared from sulfate pulp and water alone. The dispersion was fed into a manual sheet former equipped with the plate described in Example 1. Using a vacuum of 0.2 kp / cm, a web with a pulp coverage of 152 g / m 59626 and a good fluff surface was obtained.

The procedure was repeated except that the plate was changed to a plate having a thickness of 7.92 mm and having holes 3.18 mm in diameter arranged at regular intervals in a zigzag shape. The hole spacing is 4 * 78 mm. A fluffy web was obtained, but with considerable fiber loss due to the hole size and fiber size. Example 8

The procedure of Example 1 was repeated with the exception that the fiber dispersion was prepared from 30 # Veyerhauser V sulfate pulp and 30 μl of 1.3 dpf viscose fibers with a length of 4.8 mm. The dispersion solution was an aqueous solution of 0.11 # polyacrylamide (Separan AP-30) with a viscosity of 2 of about 40 sP. The fiber content was 0.1 pulp. Using a vacuum of 0.3 kp / cm, a completely fluffy web with a mass coverage of 116 g / m was obtained. Example 9

A fluffy web on both sides was formed using two perforated plates spaced vertically apart and substantially parallel to form a narrow gap therebetween. The holes in the plates were substantially similar to the holes in the plate of Example 1. The vertical dimension of both plates was about 30 mm and they were set to form about 1.39 mm at the bottom of the gap and about 2.4 mm at the top of the gap.

The dispersion was prepared from 1.3 dpf of viscose staple fibers 12 mm in length in a 0.07 # aqueous solution of polyacrylamide (Separan AR-30) having a viscosity of about 23 cP. The fiber content was 0.1 pulp. The fiber tea dispersion was fed into the gap between the sheets so that a viscous medium was drawn through the sheets with the fibers remaining between them and extending into the holes in the sheets.

Λ

A vacuum of 0.3 kp / cm was developed outside both plates. The resulting web formed a good fluff surface, but it tended to crack into layers.

The procedure was repeated using a fusible spacer to promote integration and structural integrity of the web. The plastic, fusible spacer used was a structure known as "Delnet" sold by Hercules Chemical Co. The resulting web was melted by heat and pressure, which resulted in complete integration of the spacer into the web without adversely affecting the clarity of the fluff, i.e. the protruding fiber bundles, and the high degree of fluff and softness they create. The webs were melted at 180 ° C using a heated backing plate at a pressure of 1.4 kp / cm for 6 seconds and had a pulp coverage of 170 g / m 2.

Example 10

The procedure of Example 1 was repeated with the exception that the fiber dispersion was prepared from 1.3 dpf of viscose staple fiber, length 1 ') mm, in a 0.24 # aqueous solution of poly-11,59626 acrylamide (Separan AP-30) having a viscosity of about 175 cP. The fiber content was 0.1 mass to $ 0. The pressure rise through the web-forming plate was obtained by generating an overpressure with air on the plate and not a negative pressure below it. The air pressure used was 0.26 kp / cm, which corresponded to a vacuum of 190 mmHg. The entire surface of the resulting web had good fluff formation.

As disclosed in U.S. Patent Application 341,699, the tufted, nonwoven web material is particularly suitable for use in making various consumable products. Applications include not only washcloths, dry cloths, towels, cosmetic wipes, diapers, bandages, etc., blankets, dishcloths, bandages and other medical devices, hair covers for hairdressers, head restraints, dusters, dusters, dusters, dusters, such as disposable swimming suits and caps, surgical masks, disposable headgear and industrial and household garments such as suits and fashion garments by lukiac garment spacers. The web-like web material could also be advantageously used for disposable jaw patches, tray covers, cutlery, well towels, disposable upholstery, backing and wear blankets, headgear, wall coverings, headgear and insulation, including cryogenic insulation, chronic sheathing, chronic sheathing. The web material can also be used as an air or liquid filter material, such as a coffee filter, or as an infusion material, such as tea bags, and, after appropriate treatment, can be used in various products as a cover substrate, such as a faux leather substrate or a duct spacer. Likewise, the present nonwoven web material can be formed into laminated structures including reinforced plastic film laminate, laminated or molded papers, light diffusers, lampshades or sliding door decorative papers, in addition to which the material can be used in ropes, passports or sacks or home furnishings or home furnishings. The above uses are not intended to be limiting, but merely to exemplify the usefulness of a material made in accordance with the invention, and it will be apparent to those skilled in the art that various modifications, applications, and variations may be made within the scope of the invention.

Claims (7)

59626 18 A method of making a fluffy, nonwoven, fibrous web material, comprising placing a liquid dispersion of fibers on a fiber assembly element having apertures and providing laminar flow of fibrous dispersing medium through the openings to form a plurality of non-woven fibrous webs. bundles, characterized in that a fiber collecting element is used, which is formed by a plate-like element with a smooth fiber collecting surface and a plurality of holes extending substantially tubular through the element at its collecting surface, so as to prevent the lint extends through the element, and that the fluff is compressed while they are located in the holes to form compressed fluff in the web material pi nnalle. A method according to claim 1, characterized in that a pressure rise is generated through the thickness of the fiber assembly element when a higher pressure acts on the smooth upper surface side. A method according to claim 1, characterized in that the compression comprises subjecting the lumps to a gas or liquid stream opposite to the laminar flow occurring during the formation of the lumps. Method according to Claim 3, characterized in that a thin jet is used as the gas or liquid stream. A method according to claim 1, characterized in that the two fiber collecting elements are arranged opposite each other and that the fiber dispersion is fed between them simultaneously to deposit the fibers on opposite elements and thus to form a web material with fluff on opposite surfaces. Method according to Claim 5, characterized in that the reinforcing material is placed inside the web material. A method according to claim 5, characterized in that the fluff is compressed by directing a jet flow below the element with the fluff located in the holes.