US20060011315A1 - Process and apparatus for making a sheet of aramid fibers using a foamed medium - Google Patents
Process and apparatus for making a sheet of aramid fibers using a foamed medium Download PDFInfo
- Publication number
- US20060011315A1 US20060011315A1 US11/188,119 US18811905A US2006011315A1 US 20060011315 A1 US20060011315 A1 US 20060011315A1 US 18811905 A US18811905 A US 18811905A US 2006011315 A1 US2006011315 A1 US 2006011315A1
- Authority
- US
- United States
- Prior art keywords
- fibers
- web
- aramid
- foam
- aramid fibers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/002—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines by using a foamed suspension
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
- D21H13/10—Organic non-cellulose fibres
- D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H13/26—Polyamides; Polyimides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
Definitions
- the present invention relates to a process for forming a nonwoven sheet of composite aramid fibers, and aramid fibrid, using a foam furnish. More specifically, the present invention relates to an efficient foam process for making a uniform sheet of aramid fibers, also containing aramid fibrid.
- foam in a furnish for preparing wet-laid, non-woven fibrous webs is known. See, for example, U.S. Pat. No. 4,443,297, which discloses an apparatus and method for the manufacture of a non-woven fibrous web using foam. The method involves preparing a foam furnish with 55-75% volume air, recirculating a surfactant-water solution through a forming wire followed by foam storage in a silo to eliminate excess air, and then recycling foam from the bottom of the silo. See also, U.S. Pat. Nos. 4,349,414; 4,443,299; 4,498,956; and 4,543,156.
- U.S. Pat. No. 4,488,932 relates to a method of manufacturing fibrous webs of enhanced bulk. The method involves hammermilling dry hydrophilic fibers to generate crimp, and then foam forming these fibers in 0.5 to 5 minutes to retain as much crimp as possible.
- U.S. Pat. No. 4,686,006 relates to an apparatus and method for laying down a fibrous web from a foam-fiber furnish.
- a headbox is used which includes walls defining an elongate channel extending transversely of the direction of movement of the forming wire.
- Foam forming nozzles are positioned to introduce foam-fiber furnish into the channel for turbulence, inducing impact on an oppositely disposed wall defining the channel.
- the turbulently flowing foam-fiber furnish is then introduced to the headbox slice for discharge onto the forming wire with minimized orientation of the fibers.
- Sheets of aramid fibers have been made. However, the formed sheets lack uniformly and the processes are inefficient. Moreover, the use of longer aramid fibers, e.g., longer than 0.25 inch, is desirable. Improved uniformity of dispersion and distribution of the aramid fibers in the web would be a great step forward in the art, as would increased ease and efficiency in forming the web, particularly when employing longer aramid fibers. Such sheets also containing aramid fibrid would be of great value. Techniques useful in the formation of more uniform non-woven webs made of longer aramid fibers would be of great benefit to the industry as such aramid fiber sheets have many potential uses, particularly when the sheet further contains aramid fibrid.
- the present invention is an effective and efficient method for preparing a non-woven fibrous web of aramid fibers using a foam furnish, which foam furnish is prepared by using the specific agitating means of the present invention.
- the web preferably also comprises aramid fibrid, which can improve the integrity of the sheet.
- the apparatus used for agitating the long aramid fibers in a foamed medium comprises agitating means mounted for displacement within a foamed medium and includes a leading surface facing in a direction of displacement, the leading surface including upper and lower portions converging in the direction of displacement to form a generally convex leading surface.
- the trailing surface is concave. The abrupt transition between the two surface shapes leads to cavitation or bubble formation.
- the apparatus further comprises driving means for displacing the agitating means in the direction of displacement for dispersing and mutually separating the aramid fibers within the foamed medium.
- the apparatus for agitating the fibers in a foamed medium comprises a tank having a cylindrical surface forming an agitating chamber for containing a mixture of lengthy aramid fibers, aramid fibrid and foamed medium, which can include other functional additives.
- the agitating means is mounted for rotation about an upright axis coinciding with a longitudinal axis of the agitating chamber and including a plurality of legs projecting generally radially from the axis, each leg including a leading surface facing in a direction of rotation and terminating in upper and lower trailing ends, said leading surface including upper and lower portions which converge in the direction of rotation to form a generally convex leading surface.
- the apparatus further comprises driving means for rotating the agitating means to disperse and mutually separate the aramid fibers within the foamed medium, the agitating means forming a central agitation zone, the ratio of the diameter of the agitation zone to the diameter of the agitating chamber being from about 0.5 to about 0.95.
- a method for forming a non-woven, fibrous web composed of aramid fibers, and preferably aramid fibrid which comprises first forming a foam furnish by agitating the aramid fibers (and preferably aramid fibrid) in a foamed medium, preferably aqueous, with the agitating means of the present invention. The resulting foam furnish is then passed onto a screen and defoamed using conventional techniques.
- a non-woven fibrous web comprised of very long aramid fibers, in combination with aramid fibrid, prepared by the method of the present invention.
- the web exhibits excellent uniformity, i.e., very few fiber bundles, and substantially no fiber directionality.
- FIG. 1 is a side view of an agitating apparatus of the present invention.
- FIG. 2 is a top view of an agitating apparatus of the present invention.
- FIGS. 3-5 are side and end views of the agitator.
- FIGS. 6-11 depict various acceptable shapes of the agitator legs.
- FIG. 12 is a top view of a four-legged agitator of the present invention.
- the process of the present invention comprises the steps of first forming a foam furnish by agitating a fiber mixture comprised of up to 100% of aramid fibers, in a foamed medium with the agitation apparatus of the present invention, and then passing the foam furnish onto a screen, e.g., a wire or plastic fabricated screen, and defoaming the furnish.
- the furnish will also contain aramid fibrid.
- the aramid fibrid is a small irregularly shaped piece of aramid, e.g., Nomex®, polymer that is much larger in two dimensions than it is in the third dimension. It is like a microscopic corn flake in shape.
- the large dimensions are on the order of 5 to 25 micrometers, while the third and smaller dimension is about 0.01 to 1 micrometer.
- the fibrid can serve as a bonding agent for the aramid fibers in the final web, and thus greatly enhances the integrity of the final web.
- the agitating apparatus used in the process is depicted in the Figures of the Drawing, and can be described by reference thereto.
- the agitating apparatus 10 shown in FIGS. 1-3 comprises a tank 12 having an internal cylindrical surface 14 forming a cylindrical agitating chamber 16 which receives the mixture of fibers, surfactant, and water.
- the mixture is agitated by an agitator 18 which causes the surfactant and water to form a foamed medium in which the aramid fibers are entrained.
- the agitator serves to keep the aramid fibers in a dispersed, mutually separated condition within the foamed medium, as will be hereinafter explained.
- the agitator 18 is rotatable about a vertically upright axis A which coincides with the longitudinal axis of the cylindrical agitating chamber 16 .
- the agitator is fixedly connected to the lower end of a vertical shaft 20 which is rotatably displaced by a motor 22 connected to an upper end of the shaft 20 in any suitable manner, such as by a pulley and belt connection represented by phantom lines.
- the agitator 18 comprises a plurality of legs or blades 24 projecting radially from the axis A.
- the number of legs 24 may vary, there being two legs 24 shown in FIGS. 1 and 2 .
- An alternative embodiment of the agitator 18 A shown in FIG. 12 has four legs 24 A. There could be other numbers of legs, e.g., three equally circumferentially spaced legs (not shown).
- the legs 24 shown in FIG. 1 are disposed in the same horizontal plane. Alternatively, the legs could be disposed in different planes. For example, if four legs 24 A were used as shown in FIG. 12 , they could be arranged in two pairs disposed in vertically spaced planes.
- Each leg includes a leading surface 26 facing in the direction of rotational displacement R (see FIGS. 2 and 6 ). That surface is of convex shape as the leg is viewed in cross section (see FIGS. 4 and 5 ).
- convex is meant that the upper and lower portions of the leading surface converge in the direction of rotation R and meet at a relatively blunt junction. The bluntness of the junction precludes the collection of fibers. It is also preferred that the leading surface be smooth so that fibers can slip over its surface without forming flocs, spindles, or other forms of fiber aggregates.
- FIGS. 6 and 11 Various preferred convex configurations of the leading surface are depicted in FIGS. 6 and 11 and will be discussed hereinafter.
- the leading surface 26 terminates in vertically spaced upper and lower trailing ends 28 , 30 which form edges 32 , 34 , respectively.
- the trailing surface 36 of the leg 24 which surface faces away from the direction of rotation, is non-convex, e.g., concave in FIG. 6 .
- the legs 24 are formed by a hollow cylindrical bar 40 .
- the axis A bisects the bar to form two bar sections disposed on opposite sides of the axis A.
- the portion of each bar section which faces away from the direction of rotation is truncated in that the trailing portion of the bar is cut along a plane C extending through the center of the bar (see FIG. 6 ).
- the truncation of a hollow cylinder represents a convenient way of forming the agitator, but, of course, other techniques could be used to form an agitator of the desired shape.
- the ratio of the diameter d of that agitation zone to the diameter of the agitation chamber 16 is preferably from about 0.5 to about 0.95, more preferably from about 0.65 to about 0.80; and most preferably from about 0.67 to about 0.75.
- Rotation of the agitator 18 is initiated after the mixture of aramid fibers, water, and surfactant is placed within the agitation chamber.
- Other functional additives can be added, if desired. It is also preferred that aramid fibrid be added to become part of the foam furnish and ultimately the final web.
- the surfactant and water produce a foamed medium in which the fibers are entrained.
- fibers impacted by the agitator are displaced upwardly or downwardly by the convex leading surface 26 .
- the convex leading surface of the agitator and the trailing concave following edge are important to the proper function of the apparatus. Fibers are impacted by the leading convex surface. This surface is made to be smooth so that the aramid fibers will slide along this surface without forming multi-fiber aggregates. As the aramid fibers leave this smooth convex surface they enter the abrupt transition to a concave surface. Intense cavitation occurs at this transition. Air pulled into this zone from the tank vortex or air added to the tank from some other source such as a pipe at the bottom, forms a foam which is stabilized by the presence of a surfactant which has been added to the water. This foam is characterized by small bubble size.
- the aramid fibers entering this zone of bubble formation are immediately surrounded by foam. Since the foam possesses a high viscosity and low density, the aramid fibers surrounded by foam are prevented from tangling or flocculating as would be the case if they were in water. This apparatus is unique in its ability to disperse aramid fiber into a foam uniformly.
- the entire mixture of fibers and foamed medium tends to swirl within the agitation chamber 16 .
- the baffles are preferably plate-shaped and disposed diametrically apart. The number of baffles may vary. It has been found advantageous to provide four baffles when a two-legged agitator ( FIG. 1 ) is used; to provide three or six baffles when a three legged agitator (not shown) is used; to provide four or eight baffles when a four-legged agitator ( FIG. 12 ) is used.
- baffles In the case of three baffles, they would preferably be located at the same elevation and spaced apart circumferentially equidistantly.
- baffles In the case of four baffles, they would be arranged as two pieces of diametrically opposed baffles.
- the baffles can be equally circumferentially spaced, or vertically spaced.
- the lower pair of baffles could be vertically aligned with respect to the upper pair of baffles, or they could be circumferentially offset therefrom.
- the shape of the agitator legs can assume various forms.
- the agitator 18 A could be formed of a segment of a cylinder, as in the case with the earlier described agitator 18 .
- the truncation of the cylinder would occur rearwardly of the center of the bar to form the trailing edges 32 A, 34 A.
- the agitator 18 B depicted in FIG. 8 is similar to that of FIG. 6 , but the upper and lower trailing ends of the agitator are beveled to form sharper trailing edges 32 B, 34 B.
- an agitator 18 C is depicted in which the leading convex surface 26 C and the trailing concave surface 36 C are of oblong or elliptical shape in cross-section.
- FIG. 10 an agitator 18 D is depicted in which the leading surface 26 D is the same as in FIG. 6 , but wherein the trailing surface 36 D is flat.
- An agitator 18 E depicted in FIG. 11 has a convex leading surface 26 D comprised of two flat portions 50 which converge in the direction of rotation, and which meet at a curved (blunt) junction 52 .
- the agitation is generally conducted such that the foam furnish created has an air content of at least 50% by volume, and more preferably an air content of at least 75% by volume.
- the aramid fibers agitated can be any aramid fiber, having any length.
- Commercially available aramid fibers are sold under the Trademarks Nomex® and Kevlar®.
- the present invention is uniquely applicable to very long aramid fibers.
- One of the important advantages of the present invention is that excellent webs of long aramid fibers can be easily handled and formed into an excellent web.
- the fiber mixture can comprise up to 100% aramid fibers, or the mixture can also comprise cellulosic, non-cellulosic or synthetic fibers. It is generally preferred that the mixture contain at least 50% by weight long aramid fibers.
- the mixture also comprises aramid fibrid, which can act as a binder.
- aramid fibrid due to the length of the aramid fibers of the present invention, less aramid fibrid may be needed as found in conventional aramid papers.
- a great advantage of the present invention is that the use of the foam medium provides an excellent web of aramid fibers and aramid fibrid distributed therethrough, thus allowing the fibrid to advantageously act as a binder and provide integrity throughout the entire web.
- the length of the aramid fibers used can be of any length, the present invention is most uniquely and advantageously applicable to long fibers, i.e., greater than 1 ⁇ 4 inch and at least 1 ⁇ 2 inch.
- Aramid fibers of a length of one inch, one and one-half inch, two inches or more, even three or four inches in length, can be readily incorporated into a non-woven fibrous web using the present agitator and foam process.
- the amount of aramid fibrid generally employed as a binder can be substantially reduced as the length of fiber is increased.
- conventional aramid papers comprise 60% fiber and 40% fibrid.
- 30% fibrid and less can be used. More specifically, 25% fibrid or less is preferred, with as low as 15% or even 10% fibrid still allows for a nonwoven aramid web of good strength.
- the present invention is uniquely applicable to the formation of a non-woven fibrous web comprised of aramid fibers, which can be in mixture with other fibers, such as cellulosic, synthetic or metal fibers.
- aramid fibers Any synthetic, i.e., polymeric, fiber can be used. Examples include polyester, aramid, polyamide, and polyolefin fibers.
- the aramid fibers can also be used alone or in combination with metal fibers such as stainless steel, zinc, inorganic and/or nickel fibers. Mixtures of cellulosic (wood) and synthetic or other non-cellulosic fibers can also be used in combination with the aramid fibers.
- the consistency of the foam furnish created i.e., the percentage solids in the foam furnish, is generally in the range of from 0.2 to 2.0 wt %, and is preferably about 0.5 wt % or greater.
- a consistency of greater than 0.5% yields a product having a very high basis weight.
- a consistency of 1.0 wt % or more has heretofore been unusable, and therefore the present invention permits one to operate at much higher consistencies than are conventional, if it is so desired.
- An important advantage of being able to use a high consistency is that much less process solution or foam needs to be handled.
- Inclined wire markers can generally handle 0.5 inch fibers at a consistency of 0.05%, thereby requiring, however, 10 ⁇ as much process solution or foam.
- the process of the present invention allows one to handle long aramid fibers at very high consistency and thereby enjoy the advantages and benefits thereof.
- the agitator width to fiber length ratio is preferably at least about 1.25, more preferably at least 1.75, even more preferably at least 2.5 and most preferably at least 3.0. These higher ratios are preferred because they more consistently provide the best formed and most uniform non-woven web products independently of the other variables, such as the RPM of the agitator.
- the foamed medium in which the aramid fibers are agitated can be formed during the agitation, or can be formed prior to the agitation of the fibers.
- the order of addition of water, chemicals (binder), surfactant and fiber is not important.
- the surfactant, water and aramid fiber can be added into the mixing chamber in any order.
- a successful foam dispersed aramid fiber will result. It is generally preferred, however, to not mix the fibers in the water without the presence of a surfactant. Since no foam would be generated without the surfactant, the aramid fibers would tend to tangle and agglomerate. It is possible, however, to successfully disperse the aramid fibers in a pre-existing foam.
- the concentration of the surfactant depends on the surfactant. Generally, a concentration of about 0.1 wt % in the solution is preferred for a strong foam forming surfactant. If the surfactant is a weaker foam former, a stronger concentration may be preferred. Anionic, non-ionic and cationic surfactants can all be used, with appropriate adjustments in concentration where needed.
- the time the foam furnish is mixed by the agitator of the present invention can vary greatly, as it is only important that a good dispersion of the fiber in the foam is achieved. Once a good dispersion has been achieved, longer mixing or agitation is generally neither helpful or harmful.
- the temperature of the foam furnish can also vary greatly.
- the temperature need only be such so as to allow a foam to be generated.
- polymeric binders can be added.
- polyvinyl alcohol powder has provided good results, and is a preferred additive. The presence of the fibrid, however, greatly lessens the need for polymeric binders.
- the foam furnish is then passed onto a screen, such as that generally used in a typical Foudrinier machine.
- the foam furnish is then defoamed by using vacuum or suction boxes.
- the foam furnish could be deposited on a screen using a pressure former.
- Any of the conventional methods and apparatus for forming a fibrous web while using a foam can be employed with the foam furnish of the present invention.
- the use of the agitation means of the present invention provides a foam furnish with a uniform dispersion of the fibers.
- the fibrous web obtained upon defoaming is a web exhibiting good individual fiber separation and a very uniform distribution.
- Such a uniform fibrous web is obtained even when one employs very long fibers, such as fibers having a length of one-half inch, one inch, two inches or longer, and even if cellulosic, synthetic, refractory, or metal fibers are mixed with the aramid fibers.
- a great advantage of the present invention is that it permits one to make a fibrous web comprised of long aramid fibers, if desired, in combination with other types of fibers, as easily and as quickly as one could make a paper web.
- the presence of the aramid fibrid also improves the integrity of the product and is easily and effectively integrated into the web using the process of the present invention.
- the uniform, non-woven webs prepared in accordance with the present invention, employing aramid fibers, can find many useful applications, particularly for high temperature insulation, e.g., in a transformer. Other applications would include diffusion layers in fuel cells and battery membranes. It is the uniformity of the non-woven web achieved through the practice of the present invention, and the use of fibrid to enhance integrity and consistency, which allows the webs of the present invention to be successfully applied.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Paper (AREA)
- Nonwoven Fabrics (AREA)
Abstract
Description
- This application claims the benefit of U.S. Provisional Application No. 60/409,231, filed on Sep. 10, 2002, the entirety of which is hereby incorporated by reference in its entirety.
- 1. Field of the Invention
- The present invention relates to a process for forming a nonwoven sheet of composite aramid fibers, and aramid fibrid, using a foam furnish. More specifically, the present invention relates to an efficient foam process for making a uniform sheet of aramid fibers, also containing aramid fibrid.
- 2. Description of the Related Art
- The use of foam in a furnish for preparing wet-laid, non-woven fibrous webs is known. See, for example, U.S. Pat. No. 4,443,297, which discloses an apparatus and method for the manufacture of a non-woven fibrous web using foam. The method involves preparing a foam furnish with 55-75% volume air, recirculating a surfactant-water solution through a forming wire followed by foam storage in a silo to eliminate excess air, and then recycling foam from the bottom of the silo. See also, U.S. Pat. Nos. 4,349,414; 4,443,299; 4,498,956; and 4,543,156.
- U.S. Pat. No. 4,488,932 relates to a method of manufacturing fibrous webs of enhanced bulk. The method involves hammermilling dry hydrophilic fibers to generate crimp, and then foam forming these fibers in 0.5 to 5 minutes to retain as much crimp as possible.
- U.S. Pat. No. 4,686,006 relates to an apparatus and method for laying down a fibrous web from a foam-fiber furnish. A headbox is used which includes walls defining an elongate channel extending transversely of the direction of movement of the forming wire. Foam forming nozzles are positioned to introduce foam-fiber furnish into the channel for turbulence, inducing impact on an oppositely disposed wall defining the channel. The turbulently flowing foam-fiber furnish is then introduced to the headbox slice for discharge onto the forming wire with minimized orientation of the fibers.
- Other patents which relate to the use of foam in making non-woven fibrous webs include U.S. Pat. Nos. 3,716,449; 3,938,782; 3,871,952; 3,837,999; 3,876,498; 3,846,232; 4,062,721; 3,746,613, 4,056,456; 5,720,851; 5,904,809; 6,238,518 and 6,258,203.
- Sheets of aramid fibers have been made. However, the formed sheets lack uniformly and the processes are inefficient. Moreover, the use of longer aramid fibers, e.g., longer than 0.25 inch, is desirable. Improved uniformity of dispersion and distribution of the aramid fibers in the web would be a great step forward in the art, as would increased ease and efficiency in forming the web, particularly when employing longer aramid fibers. Such sheets also containing aramid fibrid would be of great value. Techniques useful in the formation of more uniform non-woven webs made of longer aramid fibers would be of great benefit to the industry as such aramid fiber sheets have many potential uses, particularly when the sheet further contains aramid fibrid.
- Accordingly, it is an object of the present invention to provide a novel process for forming a non-woven fibrous web of aramid fibers and aramid fibrid using foam, which process provides a web in which the fibers are uniformly and evenly distributed, and the web/sheet displays great integrity.
- This and other objects and features of the invention will become apparent to one skilled in the art upon a review of the following description, the figures of the drawing, and the claims.
- Provided by the present invention is an effective and efficient method for preparing a non-woven fibrous web of aramid fibers using a foam furnish, which foam furnish is prepared by using the specific agitating means of the present invention. The web preferably also comprises aramid fibrid, which can improve the integrity of the sheet.
- The apparatus used for agitating the long aramid fibers in a foamed medium comprises agitating means mounted for displacement within a foamed medium and includes a leading surface facing in a direction of displacement, the leading surface including upper and lower portions converging in the direction of displacement to form a generally convex leading surface. The trailing surface is concave. The abrupt transition between the two surface shapes leads to cavitation or bubble formation. The apparatus further comprises driving means for displacing the agitating means in the direction of displacement for dispersing and mutually separating the aramid fibers within the foamed medium.
- More specifically, the apparatus for agitating the fibers in a foamed medium comprises a tank having a cylindrical surface forming an agitating chamber for containing a mixture of lengthy aramid fibers, aramid fibrid and foamed medium, which can include other functional additives. The agitating means is mounted for rotation about an upright axis coinciding with a longitudinal axis of the agitating chamber and including a plurality of legs projecting generally radially from the axis, each leg including a leading surface facing in a direction of rotation and terminating in upper and lower trailing ends, said leading surface including upper and lower portions which converge in the direction of rotation to form a generally convex leading surface. The apparatus further comprises driving means for rotating the agitating means to disperse and mutually separate the aramid fibers within the foamed medium, the agitating means forming a central agitation zone, the ratio of the diameter of the agitation zone to the diameter of the agitating chamber being from about 0.5 to about 0.95.
- Thus, by the present invention there is provided a method for forming a non-woven, fibrous web composed of aramid fibers, and preferably aramid fibrid, which comprises first forming a foam furnish by agitating the aramid fibers (and preferably aramid fibrid) in a foamed medium, preferably aqueous, with the agitating means of the present invention. The resulting foam furnish is then passed onto a screen and defoamed using conventional techniques.
- In another embodiment of the present invention there is provided a non-woven fibrous web comprised of very long aramid fibers, in combination with aramid fibrid, prepared by the method of the present invention. The web exhibits excellent uniformity, i.e., very few fiber bundles, and substantially no fiber directionality.
-
FIG. 1 is a side view of an agitating apparatus of the present invention. -
FIG. 2 is a top view of an agitating apparatus of the present invention. -
FIGS. 3-5 are side and end views of the agitator. -
FIGS. 6-11 depict various acceptable shapes of the agitator legs. -
FIG. 12 is a top view of a four-legged agitator of the present invention. - The process of the present invention comprises the steps of first forming a foam furnish by agitating a fiber mixture comprised of up to 100% of aramid fibers, in a foamed medium with the agitation apparatus of the present invention, and then passing the foam furnish onto a screen, e.g., a wire or plastic fabricated screen, and defoaming the furnish. Preferably, the furnish will also contain aramid fibrid. The aramid fibrid is a small irregularly shaped piece of aramid, e.g., Nomex®, polymer that is much larger in two dimensions than it is in the third dimension. It is like a microscopic corn flake in shape. The large dimensions are on the order of 5 to 25 micrometers, while the third and smaller dimension is about 0.01 to 1 micrometer. The fibrid can serve as a bonding agent for the aramid fibers in the final web, and thus greatly enhances the integrity of the final web. The agitating apparatus used in the process is depicted in the Figures of the Drawing, and can be described by reference thereto.
- The
agitating apparatus 10 shown inFIGS. 1-3 comprises atank 12 having an internalcylindrical surface 14 forming a cylindrical agitatingchamber 16 which receives the mixture of fibers, surfactant, and water. The mixture is agitated by anagitator 18 which causes the surfactant and water to form a foamed medium in which the aramid fibers are entrained. In particular, the agitator serves to keep the aramid fibers in a dispersed, mutually separated condition within the foamed medium, as will be hereinafter explained. - The
agitator 18 is rotatable about a vertically upright axis A which coincides with the longitudinal axis of the cylindricalagitating chamber 16. The agitator is fixedly connected to the lower end of avertical shaft 20 which is rotatably displaced by amotor 22 connected to an upper end of theshaft 20 in any suitable manner, such as by a pulley and belt connection represented by phantom lines. - The
agitator 18 comprises a plurality of legs orblades 24 projecting radially from the axis A. The number oflegs 24 may vary, there being twolegs 24 shown inFIGS. 1 and 2 . An alternative embodiment of theagitator 18A shown inFIG. 12 has fourlegs 24A. There could be other numbers of legs, e.g., three equally circumferentially spaced legs (not shown). Thelegs 24 shown inFIG. 1 are disposed in the same horizontal plane. Alternatively, the legs could be disposed in different planes. For example, if fourlegs 24A were used as shown inFIG. 12 , they could be arranged in two pairs disposed in vertically spaced planes. - Each leg includes a leading
surface 26 facing in the direction of rotational displacement R (seeFIGS. 2 and 6 ). That surface is of convex shape as the leg is viewed in cross section (seeFIGS. 4 and 5 ). By convex is meant that the upper and lower portions of the leading surface converge in the direction of rotation R and meet at a relatively blunt junction. The bluntness of the junction precludes the collection of fibers. It is also preferred that the leading surface be smooth so that fibers can slip over its surface without forming flocs, spindles, or other forms of fiber aggregates. - Various preferred convex configurations of the leading surface are depicted in
FIGS. 6 and 11 and will be discussed hereinafter. - The leading
surface 26 terminates in vertically spaced upper and lower trailing ends 28, 30 which form edges 32, 34, respectively. The trailingsurface 36 of theleg 24, which surface faces away from the direction of rotation, is non-convex, e.g., concave inFIG. 6 . - The
legs 24 are formed by a hollowcylindrical bar 40. The axis A bisects the bar to form two bar sections disposed on opposite sides of the axis A. The portion of each bar section which faces away from the direction of rotation is truncated in that the trailing portion of the bar is cut along a plane C extending through the center of the bar (seeFIG. 6 ). The truncation of a hollow cylinder represents a convenient way of forming the agitator, but, of course, other techniques could be used to form an agitator of the desired shape. - As the agitator rotates, it creates a circular agitation zone Z in the center of the agitation chamber or tank 16 (see
FIG. 2 ). The ratio of the diameter d of that agitation zone to the diameter of the agitation chamber 16 (i.e., d/D) is preferably from about 0.5 to about 0.95, more preferably from about 0.65 to about 0.80; and most preferably from about 0.67 to about 0.75. - Rotation of the
agitator 18 is initiated after the mixture of aramid fibers, water, and surfactant is placed within the agitation chamber. Other functional additives can be added, if desired. It is also preferred that aramid fibrid be added to become part of the foam furnish and ultimately the final web. In response to that rotation, the surfactant and water produce a foamed medium in which the fibers are entrained. As theagitator 18 travels through the mixture, fibers impacted by the agitator are displaced upwardly or downwardly by the convex leadingsurface 26. - The convex leading surface of the agitator and the trailing concave following edge are important to the proper function of the apparatus. Fibers are impacted by the leading convex surface. This surface is made to be smooth so that the aramid fibers will slide along this surface without forming multi-fiber aggregates. As the aramid fibers leave this smooth convex surface they enter the abrupt transition to a concave surface. Intense cavitation occurs at this transition. Air pulled into this zone from the tank vortex or air added to the tank from some other source such as a pipe at the bottom, forms a foam which is stabilized by the presence of a surfactant which has been added to the water. This foam is characterized by small bubble size. Thus the aramid fibers entering this zone of bubble formation are immediately surrounded by foam. Since the foam possesses a high viscosity and low density, the aramid fibers surrounded by foam are prevented from tangling or flocculating as would be the case if they were in water. This apparatus is unique in its ability to disperse aramid fiber into a foam uniformly.
- The entire mixture of fibers and foamed medium, preferably also containing the aramid fibrid, tends to swirl within the
agitation chamber 16. It has been found preferably to provide a plurality ofbaffles 42 projecting radially inwardly from thesurface 14 of theagitation chamber 16 in order to deflect the swirling mixture inwardly from thesurface 14. This prevents the aramid fibers from accumulating at thesurface 14 due to centrifugal force. The baffles are preferably plate-shaped and disposed diametrically apart. The number of baffles may vary. It has been found advantageous to provide four baffles when a two-legged agitator (FIG. 1 ) is used; to provide three or six baffles when a three legged agitator (not shown) is used; to provide four or eight baffles when a four-legged agitator (FIG. 12 ) is used. - In the case of three baffles, they would preferably be located at the same elevation and spaced apart circumferentially equidistantly.
- In the case of four baffles, they would be arranged as two pieces of diametrically opposed baffles. The baffles can be equally circumferentially spaced, or vertically spaced.
- The lower pair of baffles could be vertically aligned with respect to the upper pair of baffles, or they could be circumferentially offset therefrom.
- As pointed out earlier, the shape of the agitator legs can assume various forms. For example, as shown in
FIG. 7 theagitator 18A could be formed of a segment of a cylinder, as in the case with the earlier describedagitator 18. However, the truncation of the cylinder would occur rearwardly of the center of the bar to form the trailingedges - The
agitator 18B depicted inFIG. 8 is similar to that ofFIG. 6 , but the upper and lower trailing ends of the agitator are beveled to formsharper trailing edges - In
FIG. 9 , anagitator 18C is depicted in which the leadingconvex surface 26C and the trailingconcave surface 36C are of oblong or elliptical shape in cross-section. - In
FIG. 10 , anagitator 18D is depicted in which the leadingsurface 26D is the same as inFIG. 6 , but wherein the trailingsurface 36D is flat. - An
agitator 18E depicted inFIG. 11 has a convexleading surface 26D comprised of twoflat portions 50 which converge in the direction of rotation, and which meet at a curved (blunt)junction 52. - The agitation is generally conducted such that the foam furnish created has an air content of at least 50% by volume, and more preferably an air content of at least 75% by volume.
- The aramid fibers agitated can be any aramid fiber, having any length. Commercially available aramid fibers are sold under the Trademarks Nomex® and Kevlar®. The present invention is uniquely applicable to very long aramid fibers. One of the important advantages of the present invention is that excellent webs of long aramid fibers can be easily handled and formed into an excellent web. The fiber mixture can comprise up to 100% aramid fibers, or the mixture can also comprise cellulosic, non-cellulosic or synthetic fibers. It is generally preferred that the mixture contain at least 50% by weight long aramid fibers.
- Preferably, the mixture also comprises aramid fibrid, which can act as a binder. However, due to the length of the aramid fibers of the present invention, less aramid fibrid may be needed as found in conventional aramid papers. A great advantage of the present invention, however, is that the use of the foam medium provides an excellent web of aramid fibers and aramid fibrid distributed therethrough, thus allowing the fibrid to advantageously act as a binder and provide integrity throughout the entire web.
- While the length of the aramid fibers used can be of any length, the present invention is most uniquely and advantageously applicable to long fibers, i.e., greater than ¼ inch and at least ½ inch. Aramid fibers of a length of one inch, one and one-half inch, two inches or more, even three or four inches in length, can be readily incorporated into a non-woven fibrous web using the present agitator and foam process.
- The amount of aramid fibrid generally employed as a binder can be substantially reduced as the length of fiber is increased. For example, conventional aramid papers comprise 60% fiber and 40% fibrid. In the papers of the present invention, 30% fibrid and less can be used. More specifically, 25% fibrid or less is preferred, with as low as 15% or even 10% fibrid still allows for a nonwoven aramid web of good strength.
- As noted above, the present invention is uniquely applicable to the formation of a non-woven fibrous web comprised of aramid fibers, which can be in mixture with other fibers, such as cellulosic, synthetic or metal fibers. Any synthetic, i.e., polymeric, fiber can be used. Examples include polyester, aramid, polyamide, and polyolefin fibers. The aramid fibers can also be used alone or in combination with metal fibers such as stainless steel, zinc, inorganic and/or nickel fibers. Mixtures of cellulosic (wood) and synthetic or other non-cellulosic fibers can also be used in combination with the aramid fibers.
- The consistency of the foam furnish created, i.e., the percentage solids in the foam furnish, is generally in the range of from 0.2 to 2.0 wt %, and is preferably about 0.5 wt % or greater. A consistency of greater than 0.5% yields a product having a very high basis weight. A consistency of 1.0 wt % or more has heretofore been unusable, and therefore the present invention permits one to operate at much higher consistencies than are conventional, if it is so desired. An important advantage of being able to use a high consistency is that much less process solution or foam needs to be handled. Inclined wire markers can generally handle 0.5 inch fibers at a consistency of 0.05%, thereby requiring, however, 10× as much process solution or foam. The process of the present invention allows one to handle long aramid fibers at very high consistency and thereby enjoy the advantages and benefits thereof.
- The agitator width to fiber length ratio is preferably at least about 1.25, more preferably at least 1.75, even more preferably at least 2.5 and most preferably at least 3.0. These higher ratios are preferred because they more consistently provide the best formed and most uniform non-woven web products independently of the other variables, such as the RPM of the agitator.
- The foamed medium in which the aramid fibers are agitated can be formed during the agitation, or can be formed prior to the agitation of the fibers. When forming the foamed medium in situ, the order of addition of water, chemicals (binder), surfactant and fiber is not important. The surfactant, water and aramid fiber can be added into the mixing chamber in any order. Once the agitator is started, a successful foam dispersed aramid fiber will result. It is generally preferred, however, to not mix the fibers in the water without the presence of a surfactant. Since no foam would be generated without the surfactant, the aramid fibers would tend to tangle and agglomerate. It is possible, however, to successfully disperse the aramid fibers in a pre-existing foam.
- The concentration of the surfactant depends on the surfactant. Generally, a concentration of about 0.1 wt % in the solution is preferred for a strong foam forming surfactant. If the surfactant is a weaker foam former, a stronger concentration may be preferred. Anionic, non-ionic and cationic surfactants can all be used, with appropriate adjustments in concentration where needed.
- The time the foam furnish is mixed by the agitator of the present invention can vary greatly, as it is only important that a good dispersion of the fiber in the foam is achieved. Once a good dispersion has been achieved, longer mixing or agitation is generally neither helpful or harmful.
- The temperature of the foam furnish can also vary greatly. The temperature need only be such so as to allow a foam to be generated.
- Other conventional, functional additives can also be added to the foam furnish, as long as they do not interfere with the foaming nature of the surfactant. Polymeric binders can be added. For example, polyvinyl alcohol powder has provided good results, and is a preferred additive. The presence of the fibrid, however, greatly lessens the need for polymeric binders.
- Once the foam furnish has been made, the foam furnish is then passed onto a screen, such as that generally used in a typical Foudrinier machine. The foam furnish is then defoamed by using vacuum or suction boxes. Alternatively, the foam furnish could be deposited on a screen using a pressure former. Any of the conventional methods and apparatus for forming a fibrous web while using a foam can be employed with the foam furnish of the present invention. The use of the agitation means of the present invention provides a foam furnish with a uniform dispersion of the fibers. As a result, the fibrous web obtained upon defoaming is a web exhibiting good individual fiber separation and a very uniform distribution. As well, there is controlled directionality of the fibers depending on the design of the headbox.
- Such a uniform fibrous web is obtained even when one employs very long fibers, such as fibers having a length of one-half inch, one inch, two inches or longer, and even if cellulosic, synthetic, refractory, or metal fibers are mixed with the aramid fibers. A great advantage of the present invention is that it permits one to make a fibrous web comprised of long aramid fibers, if desired, in combination with other types of fibers, as easily and as quickly as one could make a paper web. The presence of the aramid fibrid also improves the integrity of the product and is easily and effectively integrated into the web using the process of the present invention.
- The uniform, non-woven webs prepared in accordance with the present invention, employing aramid fibers, can find many useful applications, particularly for high temperature insulation, e.g., in a transformer. Other applications would include diffusion layers in fuel cells and battery membranes. It is the uniformity of the non-woven web achieved through the practice of the present invention, and the use of fibrid to enhance integrity and consistency, which allows the webs of the present invention to be successfully applied.
- While the invention has been described with preferred embodiments, it is to be understood that variations and modifications may be resorted to as will be apparent to those skilled in the art. Such variations and modifications are to be considered within the purview and the scope of the claims appended hereto.
Claims (11)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/188,119 US20060011315A1 (en) | 2002-09-10 | 2005-07-25 | Process and apparatus for making a sheet of aramid fibers using a foamed medium |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US40923102P | 2002-09-10 | 2002-09-10 | |
US10/657,134 US6921459B2 (en) | 2002-09-10 | 2003-09-09 | Process for making a sheet of aramid fibers using a foamed medium |
US11/188,119 US20060011315A1 (en) | 2002-09-10 | 2005-07-25 | Process and apparatus for making a sheet of aramid fibers using a foamed medium |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/657,134 Continuation US6921459B2 (en) | 2002-09-10 | 2003-09-09 | Process for making a sheet of aramid fibers using a foamed medium |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060011315A1 true US20060011315A1 (en) | 2006-01-19 |
Family
ID=31997799
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/657,134 Expired - Fee Related US6921459B2 (en) | 2002-09-10 | 2003-09-09 | Process for making a sheet of aramid fibers using a foamed medium |
US11/188,119 Abandoned US20060011315A1 (en) | 2002-09-10 | 2005-07-25 | Process and apparatus for making a sheet of aramid fibers using a foamed medium |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/657,134 Expired - Fee Related US6921459B2 (en) | 2002-09-10 | 2003-09-09 | Process for making a sheet of aramid fibers using a foamed medium |
Country Status (3)
Country | Link |
---|---|
US (2) | US6921459B2 (en) |
AU (1) | AU2003267102A1 (en) |
WO (1) | WO2004025030A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040140072A1 (en) * | 2002-09-10 | 2004-07-22 | Fibermark, Inc. | High temperature paper containing aramid component |
US10519606B2 (en) | 2016-12-22 | 2019-12-31 | Kimberly-Clark Wordlwide, Inc. | Process and system for reorienting fibers in a foam forming process |
US11255051B2 (en) | 2017-11-29 | 2022-02-22 | Kimberly-Clark Worldwide, Inc. | Fibrous sheet with improved properties |
US11313061B2 (en) | 2018-07-25 | 2022-04-26 | Kimberly-Clark Worldwide, Inc. | Process for making three-dimensional foam-laid nonwovens |
US11591755B2 (en) | 2015-11-03 | 2023-02-28 | Kimberly-Clark Worldwide, Inc. | Paper tissue with high bulk and low lint |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI115512B (en) * | 2001-11-09 | 2005-05-31 | Ahlstrom Glassfibre Oy | Method and apparatus for performing foam molding |
US6921459B2 (en) * | 2002-09-10 | 2005-07-26 | Fibermark, Inc. | Process for making a sheet of aramid fibers using a foamed medium |
ES2523728T3 (en) * | 2010-06-15 | 2014-12-01 | Ahlstrom Corporation | Scrubbed fibrous support containing apergaminable synthetic fibers and method of manufacture |
FI126194B (en) * | 2013-09-13 | 2016-08-15 | Teknologian Tutkimuskeskus Vtt Oy | A method for forming a fibrous product |
FI20176206A1 (en) | 2017-12-31 | 2019-07-01 | Paptic Oy | Method of producing a fibrous product and a fibrous product |
BR112022010896A2 (en) * | 2019-12-31 | 2022-09-06 | Kimberly Clark Co | FOAM-BASED MANUFACTURING SYSTEM AND PROCESS |
Citations (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007840A (en) * | 1958-04-03 | 1961-11-07 | Du Pont | Process of dispersing fibrous material in a foam and resulting product |
US3716449A (en) * | 1966-05-31 | 1973-02-13 | Wiggins Teape Res Dev | Method and apparatus for forming a non-woven fibrous web from a foamed fiber furnish |
US3746613A (en) * | 1971-02-11 | 1973-07-17 | E Vauhkonen | Twin wire paper making machine wherein the wires travel in an arc |
US3756908A (en) * | 1971-02-26 | 1973-09-04 | Du Pont | Synthetic paper structures of aromatic polyamides |
US3837999A (en) * | 1971-12-20 | 1974-09-24 | Kimberly Clark Co | Method of controlling the orientation of fibers in a foam formed sheet |
US3846232A (en) * | 1973-03-23 | 1974-11-05 | Valmet Oy | Twin-wire paper forming with wires wrapping around a suction web-forming breast roll and then following a curved path to a suction couch roll |
US3871952A (en) * | 1972-04-07 | 1975-03-18 | Wiggins Teape Res Dev | Manufacture of non-woven fibrous material from a foamed furnish |
US3876498A (en) * | 1973-09-14 | 1975-04-08 | Beloit Corp | Controlled forming wire separation on impervious roll of twin-wire papermaking machine |
US3938782A (en) * | 1972-04-07 | 1976-02-17 | Wiggins Teape Research & Development Limited | Apparatus for producing a foamed fibre dispersion |
US4056456A (en) * | 1973-11-22 | 1977-11-01 | Sumitomo Chemical Company, Limited | Process for preparing novel thin films |
US4062721A (en) * | 1976-10-26 | 1977-12-13 | Conwed Corporation | Use of surfactant to increase water removal from fibrous web |
US4349414A (en) * | 1978-04-25 | 1982-09-14 | Ab Karlstads Mekaniska Werkstad | Method for forming a multilayer jet of paper making stock |
US4398995A (en) * | 1980-05-26 | 1983-08-16 | Teijin Limited | Papery product |
US4443297A (en) * | 1980-08-18 | 1984-04-17 | James River-Dixie/Northern, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4443299A (en) * | 1980-08-18 | 1984-04-17 | James River-Dixie/Northern, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4488932A (en) * | 1982-08-18 | 1984-12-18 | James River-Dixie/Northern, Inc. | Fibrous webs of enhanced bulk and method of manufacturing same |
US4498956A (en) * | 1981-09-25 | 1985-02-12 | James River-Norwalk, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4515656A (en) * | 1981-08-28 | 1985-05-07 | E. I. Du Pont De Nemours And Company | Low density nonwoven sheets |
US4529481A (en) * | 1979-06-11 | 1985-07-16 | Teijin Ltd. | Synthetic polyester pulp and process for preparing same |
US4543156A (en) * | 1982-05-19 | 1985-09-24 | James River-Norwalk, Inc. | Method for manufacture of a non-woven fibrous web |
US4686006A (en) * | 1984-04-16 | 1987-08-11 | James River - Norwalk, Inc. | Apparatus and method for the manufacture of fibrous webs |
US5720851A (en) * | 1994-07-13 | 1998-02-24 | Sca Hygiene Paper Ab | Method and arrangement for producing a foam-formed fibre or paper web |
US5833807A (en) * | 1997-04-17 | 1998-11-10 | E. I. Du Pont De Nemours And Company | Aramid dispersions and aramid sheets of increased uniformity |
US5904809A (en) * | 1997-09-04 | 1999-05-18 | Ahlstrom Paper Group Oy | Introduction of fiber-free foam into, or near, a headbox during foam process web making |
US6238518B1 (en) * | 1999-03-02 | 2001-05-29 | Ahlstrom Paper Group Oy | Foam process for producing multi-layered webs |
US6258203B1 (en) * | 1999-09-21 | 2001-07-10 | Ahlstrom Glassfibre Oy | Base webs for printed circuit board production using the foam process and acrylic fibers |
US20030193836A1 (en) * | 2002-04-10 | 2003-10-16 | Kinsley Homan B. | Process and apparatus for making sheet of fibers using a foamed medium |
US6830656B2 (en) * | 2002-04-30 | 2004-12-14 | Fibermark, Inc. | Non-woven fiber webs with nylon binder |
US6921459B2 (en) * | 2002-09-10 | 2005-07-26 | Fibermark, Inc. | Process for making a sheet of aramid fibers using a foamed medium |
-
2003
- 2003-09-09 US US10/657,134 patent/US6921459B2/en not_active Expired - Fee Related
- 2003-09-10 WO PCT/US2003/028375 patent/WO2004025030A1/en not_active Application Discontinuation
- 2003-09-10 AU AU2003267102A patent/AU2003267102A1/en not_active Abandoned
-
2005
- 2005-07-25 US US11/188,119 patent/US20060011315A1/en not_active Abandoned
Patent Citations (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3007840A (en) * | 1958-04-03 | 1961-11-07 | Du Pont | Process of dispersing fibrous material in a foam and resulting product |
US3716449A (en) * | 1966-05-31 | 1973-02-13 | Wiggins Teape Res Dev | Method and apparatus for forming a non-woven fibrous web from a foamed fiber furnish |
US3746613A (en) * | 1971-02-11 | 1973-07-17 | E Vauhkonen | Twin wire paper making machine wherein the wires travel in an arc |
US3756908A (en) * | 1971-02-26 | 1973-09-04 | Du Pont | Synthetic paper structures of aromatic polyamides |
US3837999A (en) * | 1971-12-20 | 1974-09-24 | Kimberly Clark Co | Method of controlling the orientation of fibers in a foam formed sheet |
US3871952A (en) * | 1972-04-07 | 1975-03-18 | Wiggins Teape Res Dev | Manufacture of non-woven fibrous material from a foamed furnish |
US3938782A (en) * | 1972-04-07 | 1976-02-17 | Wiggins Teape Research & Development Limited | Apparatus for producing a foamed fibre dispersion |
US3846232A (en) * | 1973-03-23 | 1974-11-05 | Valmet Oy | Twin-wire paper forming with wires wrapping around a suction web-forming breast roll and then following a curved path to a suction couch roll |
US3876498A (en) * | 1973-09-14 | 1975-04-08 | Beloit Corp | Controlled forming wire separation on impervious roll of twin-wire papermaking machine |
US4056456A (en) * | 1973-11-22 | 1977-11-01 | Sumitomo Chemical Company, Limited | Process for preparing novel thin films |
US4062721A (en) * | 1976-10-26 | 1977-12-13 | Conwed Corporation | Use of surfactant to increase water removal from fibrous web |
US4349414A (en) * | 1978-04-25 | 1982-09-14 | Ab Karlstads Mekaniska Werkstad | Method for forming a multilayer jet of paper making stock |
US4529481A (en) * | 1979-06-11 | 1985-07-16 | Teijin Ltd. | Synthetic polyester pulp and process for preparing same |
US4398995A (en) * | 1980-05-26 | 1983-08-16 | Teijin Limited | Papery product |
US4443299A (en) * | 1980-08-18 | 1984-04-17 | James River-Dixie/Northern, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4443297A (en) * | 1980-08-18 | 1984-04-17 | James River-Dixie/Northern, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4515656A (en) * | 1981-08-28 | 1985-05-07 | E. I. Du Pont De Nemours And Company | Low density nonwoven sheets |
US4498956A (en) * | 1981-09-25 | 1985-02-12 | James River-Norwalk, Inc. | Apparatus and method for the manufacture of a non-woven fibrous web |
US4543156A (en) * | 1982-05-19 | 1985-09-24 | James River-Norwalk, Inc. | Method for manufacture of a non-woven fibrous web |
US4488932A (en) * | 1982-08-18 | 1984-12-18 | James River-Dixie/Northern, Inc. | Fibrous webs of enhanced bulk and method of manufacturing same |
US4686006A (en) * | 1984-04-16 | 1987-08-11 | James River - Norwalk, Inc. | Apparatus and method for the manufacture of fibrous webs |
US5720851A (en) * | 1994-07-13 | 1998-02-24 | Sca Hygiene Paper Ab | Method and arrangement for producing a foam-formed fibre or paper web |
US5833807A (en) * | 1997-04-17 | 1998-11-10 | E. I. Du Pont De Nemours And Company | Aramid dispersions and aramid sheets of increased uniformity |
US5904809A (en) * | 1997-09-04 | 1999-05-18 | Ahlstrom Paper Group Oy | Introduction of fiber-free foam into, or near, a headbox during foam process web making |
US6238518B1 (en) * | 1999-03-02 | 2001-05-29 | Ahlstrom Paper Group Oy | Foam process for producing multi-layered webs |
US6258203B1 (en) * | 1999-09-21 | 2001-07-10 | Ahlstrom Glassfibre Oy | Base webs for printed circuit board production using the foam process and acrylic fibers |
US20030193836A1 (en) * | 2002-04-10 | 2003-10-16 | Kinsley Homan B. | Process and apparatus for making sheet of fibers using a foamed medium |
US6682215B2 (en) * | 2002-04-10 | 2004-01-27 | Fibermark, Inc. | Process and apparatus for making sheet of fibers using a foamed medium |
US6830656B2 (en) * | 2002-04-30 | 2004-12-14 | Fibermark, Inc. | Non-woven fiber webs with nylon binder |
US6921459B2 (en) * | 2002-09-10 | 2005-07-26 | Fibermark, Inc. | Process for making a sheet of aramid fibers using a foamed medium |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040140072A1 (en) * | 2002-09-10 | 2004-07-22 | Fibermark, Inc. | High temperature paper containing aramid component |
US11591755B2 (en) | 2015-11-03 | 2023-02-28 | Kimberly-Clark Worldwide, Inc. | Paper tissue with high bulk and low lint |
US10519606B2 (en) | 2016-12-22 | 2019-12-31 | Kimberly-Clark Wordlwide, Inc. | Process and system for reorienting fibers in a foam forming process |
US11255051B2 (en) | 2017-11-29 | 2022-02-22 | Kimberly-Clark Worldwide, Inc. | Fibrous sheet with improved properties |
US11313061B2 (en) | 2018-07-25 | 2022-04-26 | Kimberly-Clark Worldwide, Inc. | Process for making three-dimensional foam-laid nonwovens |
US11788221B2 (en) | 2018-07-25 | 2023-10-17 | Kimberly-Clark Worldwide, Inc. | Process for making three-dimensional foam-laid nonwovens |
Also Published As
Publication number | Publication date |
---|---|
WO2004025030A1 (en) | 2004-03-25 |
US20040144508A1 (en) | 2004-07-29 |
US6921459B2 (en) | 2005-07-26 |
AU2003267102A1 (en) | 2004-04-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6682215B2 (en) | Process and apparatus for making sheet of fibers using a foamed medium | |
US20060011315A1 (en) | Process and apparatus for making a sheet of aramid fibers using a foamed medium | |
US4049491A (en) | Viscous dispersion for forming wet-laid, non-woven fabrics | |
US4007083A (en) | Method for forming wet-laid non-woven webs | |
US4200488A (en) | Viscous dispersion for forming wet-laid, non-woven fabrics | |
US4600545A (en) | Process for the preparation of fibers from polymeric materials | |
US20110277947A1 (en) | Cellulose nanofilaments and method to produce same | |
EP0472355A1 (en) | Hydroentangled nonwoven fabric containing synthetic fibers having a ribbon-shaped crenulated cross-section and method of producing the same | |
US4265704A (en) | Method of dispersing bundles of glass fibers for making glass fiber mats by the wet-laid process | |
JPH0261195A (en) | Filter cloth made by wet piling method | |
EP3075903B1 (en) | An arrangement for and a method of manufacturing a fibrous web | |
US6616802B1 (en) | Process and apparatus for making a sheet of refractory fibers using a foamed medium | |
DE1560872B2 (en) | ||
JPS6135317B2 (en) | ||
US6830656B2 (en) | Non-woven fiber webs with nylon binder | |
CN1116477C (en) | Using centrifugal pump in foam process of producing non-woven webs | |
EP0972109B1 (en) | Process for making a wet-layed metal fiber/metal powder sheet | |
JP3218112B2 (en) | Fine fibrous polyolefin | |
EP3757288B1 (en) | A method of and an arrangement for adding a chemical to an approach flow system of a fiber web machine | |
WO2004025009A2 (en) | Non-woven fiber webs with poly(phenylene sulfide) binder | |
EP0150777B1 (en) | Method for the manufacture of a non-woven fibrous web | |
US6540875B2 (en) | Uniform metal fiber sheet | |
CA1052519A (en) | Method for producing a fibrous synthetic paper forming material | |
CA1068144A (en) | Machine made light weight glass fiber web material | |
JP6825442B2 (en) | A method of impregnating a porous sheet containing carbon fibers with a liquid substance in which a conductive solid substance is dispersed. |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FIBERMARK NORTH AMERICA, INC., VERMONT Free format text: INTELLECTUAL PROPERTY ASSIGNMENT;ASSIGNOR:FIBERMARK, INC.;REEL/FRAME:018597/0030 Effective date: 20061006 |
|
AS | Assignment |
Owner name: GENERAL ELECTRIC CAPITAL CORPORATION, AS AGENT, NE Free format text: THIRD AMENDED AND RESTATED PATENT SECURITY AGREEMENT;ASSIGNORS:FIBERMARK HOLDINGS, LLC;FIBERMARK NORTH AMERICA, INC.;REEL/FRAME:018616/0690 Effective date: 20061211 |
|
AS | Assignment |
Owner name: GENERAL ELECTRIC CAPITAL CORPORATION, AS AGENT, IL Free format text: SECURITY AGREEMENT;ASSIGNOR:FIBERMARK NORTH AMERICA, INC.;REEL/FRAME:020299/0363 Effective date: 20071228 |
|
AS | Assignment |
Owner name: FIBERMARK NORTH AMERICA, INC., VERMONT Free format text: TERMINATION AND RELEASE OF THIRD AMENDED AND RESTATED PATENT SECURITY AGREEMENT;ASSIGNOR:GENERAL ELECTRIC CAPITAL CORPORATION, AS AGENT;REEL/FRAME:020309/0150 Effective date: 20071228 Owner name: FIBERMARK HOLDINGS, LLC, VERMONT Free format text: TERMINATION AND RELEASE OF THIRD AMENDED AND RESTATED PATENT SECURITY AGREEMENT;ASSIGNOR:GENERAL ELECTRIC CAPITAL CORPORATION, AS AGENT;REEL/FRAME:020309/0150 Effective date: 20071228 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: FIBERMARK NORTH AMERICA, INC., VERMONT Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:GENERAL ELECTRIC CAPITAL CORPORATION;REEL/FRAME:036256/0160 Effective date: 20150731 |