MXPA06003385A - Method and apparatus for making an absorbent composite - Google Patents

Abstract

A method and apparatus for making an absorbent composite from continuous tow is disclosed. The method and apparatus includes the steps of or means for spreading a crimped tow;de-registering the crimped tow;shaping the de-registered tow to a substantially rectangular cross-section;and distributing a particulate onto the shaped tow. The step of or means for de-registering the crimped tow uses at least two pairs of rollers, each pair of rollers having a metal-faced roller and a rubber-face roller. The metal-faced rollers are oppositely disposed between the pair of rollers. Alternatively, the metal-faced rollers are disposed between the pair of rollers on the same side.

Description

METHOD AND APPARATUS FOR MAKING AN ABSORBENT COMPOSITE MATERIAL FIELD OF THE INVENTION The invention relates to a method and apparatus for making an absorbent composite material from a continuous tow.

BACKGROUND OF THE INVENTION An absorbent composite is the component of a disposable absorbent garment. Such garments include, but are not limited to, children's diapers or training underpants, adult incontinence products, and feminine hygiene products. Typically the absorbent composite comprises blends of fibrous materials (eg, wood pulp or paper fluff) and a superabsorbent polymer (SAP) that are sandwiched between layers, such as fabrics, non-wovens, and waterproof and permeable films. The use of continuous tow in the manufacture of absorbent composites is known. See Japanese Patent Kokoku 60-26537, US SIR H1565, and US Pat. Nos. 6,068,620; 6,253,431; and 6,543,106. Each one is described below.

Japanese Patent Kokoku 60-26537 discloses an absorbent structure which is made of pleated acetate tow and powdered pulp, but not with SAP. Referring to Figure 4, the procedure for making the absorbent structure is shown. The tow is removed from a bale and is spread by a banding air jet 14. The tow is then de-registered between pairs of rollers 16, 17. The de-registered tow is further extended and given a uniform density with a second spray. air 18. Pulverized pulp 21 extends over the open tow after it leaves the second air jet. Then absorbent sheets are added and the absorbent bearing is folded into its final form. The statutory registration of invention of E.U.A. H1565 discloses an absorbent structure which is made of a pleated acetate bast and SAP, which is preferably adhered to the open tow by a binder. The tow opens with a Korbet & Co. Model AF2 (a machine that is commonly used in the manufacture of cigarette filters) and subsequently a mixture of binder and SAP, or binder and then SAP, is added to the topa. The Patent of E.U.A. No. 6,068,620 discloses an absorbent core which is made of a fibrous pleated acetate tow and SAP between a top layer and a bottom layer. Referring to Figure 7, the SAP is added to the tow by means of a mixing chamber.

The Patent of E.U.A. Nos. 6,253,431 and 6,543,106 disclose a method for making an absorbent structure from a pleated acetate tow and SAP. Referring to Figure 1, the tow from the bale is extended by the banding jet 130. The tow is then partially unregistered (or opened) through roller assemblies 40, 60, 70. Each roller assembly has a metal roller 42, 62, 72 and a rubber roller 44, 64, 74. Preferably a liquid is applied to the open tow by a liquid addition assembly 80. Then the tow is further opened, formed into a air jet 240. Solid substances, such as SAP, are added after the fully opened and shaped tow emerges from jet 240. Solid substances are added by means of a vibratory feeder. However, there is a need for more practical methods and apparatus for making an absorbent composite.

BRIEF DESCRIPTION OF THE INVENTION A method and apparatus for making an absorbent composite from a continuous tow is described. The method and apparatus include the steps and means for extending a pleated tow; the action of unregistering the pleated tow; configure the unregistered tow; and distribute a particulate material on the configured tow. The step or means for unregistering the pleated tow uses at least two pairs of rollers, each pair of rollers having a roller with a metal face and a roller with a rubber face. The metal-faced rollers are arranged in the opposite way between the pair of rollers. Alternatively, the metal face rollers are disposed between the pair of rollers in the same direction.

DESCRIPTION OF THE DRAWINGS For the purpose of illustrating the invention, a form that is presently preferred is shown in the drawings. It being understood, however, that this invention is not limited to the precise provisions and instruments described. Figures 1, 1a, and 1b are schematic views of the present invention. Figure 2 is an elevated view of the present invention. Figure 3 is an elevated view of the deregistration mechanism of the present invention. Figure 4 is an elevated view of the configuration and distribution mechanisms of the particulate material of the present invention. Figure 5 is a somatic view of the particulate material distribution mechanism of the present invention.

Figures 6a, 6b, 6c, and 6d are elevational views of a portion of the particulate distribution mechanism of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, in which like numerals indicate like elements, there is shown in Figure 1 an apparatus 10 for making an absorbent composite from a continuous tow. The absorbent composite material described herein is for use in the manufacture of absorbent garments. Absorbent garments include, for example, diapers or underpants, adult incontinence products and feminine hygiene products. The absorbent composites described herein are particularly useful in absorbent and pledge cores described in the U.S. patent publications. Nos. 2003/0105442; 2003/0114814; 2003/01351777; and 2003/0135178, each is incorporated herein by reference. The tow is a large rope of continuous filaments of manufactured fiber without any defined twisting, which is collected in a loose, band or rope type, which are normally held together by pleating. Suitable materials for the tow include, but are not limited to, polyolefins, polyesters, polyamides, cellulosics, and mixtures thereof, of these, cellulosic fibers are preferred. The cellulosic fibers include rayon fibers, acetate (cellulose acetate) and triacetate (cellulose triacetate). Acetate tow is more preferable. For example, an acetate tow may consist of about 2,500 to about 25,000 fibers having an individual denier of about 1 to about 15, preferably 2 to 10, and more preferably 3 to 8. The total denier of a single tow band of acetate may vary from about 2,500 to about 125,000, preferably from 15,000 to 75,000, and more preferably from 20,000 to 40,000. The tow is preferably pleated, with from about 2 to 16 folds per centimeter, preferably 10 to 12 folds per centimeter. The fibers of the tow can have any cross section configuration including 'and.' 'x \ Round, crenulated, dog bone or combinations thereof. The tow may include a finish, the finish comprising from about 0.3% to about 5% by weight of the tow, preferably from 0.5 to 2.0%. The cross-sectional dimensions of the tow may vary from about 25mm to 100mm wide, preferably from 40 to 60mm, and from about 1 to 10mm in height, preferably from 2 to 5mm. The tows are commercially available and are distributed in compressed bales. In Figures 1 and 2 there is shown an apparatus 10 for making absorbent composites from a continuous tow. The apparatus 10 generally comprises: an apparatus 13 for extending the tow, that is, increasing its width from its compressed state in the bale. A deregistration apparatus 40 for unregistering the pleated fibers of the tow; a configuration apparatus 54 for giving the tow its desired cross-sectional shape; a particle distribution apparatus 56 wherein the particulate matter, that is, the SAP, can be provided to the configured tow, and a winding station 60 where the configured tow loaded with particles is sandwiched between layers and then rolled up. The winding can be eliminated and the absorbent composite material can be transported directly to a subsequent machine for formation into a final absorbent garment (see, for example, U.S. Patent Publications Nos. 2003/0105442; 2003/0114814; 2003/0134559; 2003/0135177; 2003/0135178; 2003/0150551, each is incorporated herein by reference). The bale 12 is preferably located at a right angle to the tow path through the de-registration apparatus 40, the tow configuration apparatus 54, and the particle distribution apparatus 56. The bale can be located at any location, including a position in line with the aforementioned apparatuses. However, the location at the right angle is preferable to allow easy access to the bale, to change the empty bales and allow easy visual inspection of the tow by an operator. The tow 14 is supplied to the extension apparatus 13 from the bale 12. The apparatus 13 guides the tow between two locations and extends it.

The extension apparatus 13 preferably has at least two banding jets. These banding jets work to extend and stabilize the tow as it moves through the remainder of the apparatus 10. The tow 14 is removed from the bale 12 and guided through the rings 16 to a first banding jet. 18. The banding jet 18 is a device that is used to extend (i.e., increase the width) and stabilize the tow 14. The banding jet 18, see Figure 1a, generally comprises a plate 20 having a channel 22 with an air nozzle 24 which is located within the channel 22. Any conventional banding jet can be used, see, for example, the US patent No. 3,226,773, or the patent application of E.U.A. with serial number No. 09 / 219,818 filed on December 23, 1998, both are incorporated herein by reference. The air nozzle 24 is shown with an inverted -vee shape, however other shapes or patterns are possible, for example, the grooves can be replaced by holes. The inverted vee can have a width of 50 -140 mm. Compressed air is blown through the air nozzle 24 and partially extends the tow. The pressure of the compressed air can vary from 0.0351 to 0.3515 kg / cm2 gauge, preferably from 0.1757 to 0.2109 kg / cm2 gauge. The width of the channel 22 is referred to as WL The carrier structure of the tow 26 transports the tow 14 to exit the banding jet 18 at a distance from the jet 18 to the remainder of the apparatus 10. The guide roller 28, which is located at the distal end of the carrier 26 re-orientates the tow to enter the rest of the apparatus 10. The second banding jet 30 receives the tow 14 from the guide roller 28. The second banding jet 30, see figure 1 b, comprises a plate 32 having a channel 34 with an air nozzle 36. Any conventional banding jet can be used, for example that which can be seen in the US patent No. 3,226,773 or in the patent application of E.U.A. with serial number No. 09 / 219,818 filed on December 23, 1998, both are incorporated herein by reference. The air nozzle 36 appears with a vee shape, however, other shapes or patterns are permissible, for example the grooves can be replaced by holes. The vee can have a width of 70-155 mm. Compressed air is blown through the air nozzle 36 and partially extends the tow. The pressure of the compressed air can vary from 0.0351 to 0.3515 kg / cm2, preferably from 0.2109 to 0.2460 kg / cm2. Channel 34 has a width W2. Preferably, Wi is less than W2. The cabinet 38 (appearing faded) contains the de-registration apparatus 40 which receives the tow 14 from the extension apparatus 13. The cabinet 38 acts as a protective device to prevent contaminants such as adhesives from adhering to or fouling the surfaces of the cabinet. Deregistration apparatus roll 40, and as a safety device. Although cabinet 38 is preferable, other means may be used to achieve the protection function, such as curtains, air curtains, wire cages. The cabinet 38 will be described in more detail below. The deregistration apparatus 40, which is preferably contained within the cabinet 38, has at least two pairs of rollers 42 and 48. On unregistration, the individual pleated filaments of the tow are deregistered (or opened) and prepared for configuration. The pair of rollers 42 has a roller with a metal face 44 and a roller with a rubber face 46 (rubber face refers to any elastic polymer). The pair of rollers 48 also has a roller with metal face 50 and a roller with rubber face 52 (rubber face refers to any elastic polymer). The rollers with metal are driven and have diameters of 160 mm. The rollers with rubber face have diameters of 250 mm. The pair of rollers 42 and 48 can be oriented vertically (as shown), horizontally or at some angle between the two orientations. The metal face rollers 48 and 50 can be smooth, grooved, threaded, textured, or combinations thereof. When they are grooved or threaded, the ratio of the open surface to the flat surface can normally vary from 90:10 to 10:90, preferably at 35:75.; 50:50; and 75:25, and more preferably 75:25. The rubber-faced rollers are preferably placed opposite each other and in pairs, as shown, but can be arranged on the same side, preferably on the side closest to the apparatus 54, in order to that the fibers in the tow do not get entangled in the open surface of the metal rollers. The pressing pressure between each pair of rollers 42 and 48 is (2) bar with a pressure cylinder with a diameter of 70 mm. The pair of rollers 48 has a greater surface velocity than the pair of rollers 42. When a cellulose acetate tow is used, the ratio of the speed of the roller for the pair 48 (S48) to the pair 42 (S42) may vary of 1 < S48 / S42 < 2, and S48 / S42 is preferably 1.1-1.7, and more preferably 1.3-1.4. Optionally, a liquid application station 53 which is located after the de-registration apparatus 40 can be used. Such liquids can be used, for example, to facilitate the joining of the fibers in the tow or of the particles to the tow, or for deodorizing or perfuming the absorbent composite material, or adding an antimicrobial agent to the composite material, or for altering the hydrophilicity of the tow. Such liquids include water, hydrophilic liquids (such as alcohols, glycols, dimethyl sulfide, ketones, ethers, and the like), plasticizers (such as triacetins), surfactants, and solutions containing plasticizers, surfactants, and the like. The liquid application station 53 may include sprayer nozzles, disc applicators, rotating brush applicators, wick contact rollers, and the like as is known in the art. The tow configuration apparatus 54 receives the tow 14 from the de-registration apparatus 40. The tow configuration apparatus 54 is used to configure the open tow into a predetermined cross-sectional shape, preferably a generally rectangular cross-section, for use it in an absorbent garment. Other shapes of cross section are also possible, these include: circular, oval, square, grooved, and grooved. For example, a preferred tow configuration apparatus 54 is illustrated in the U.S.A. No. 6,253,431, which is incorporated herein by reference. Another tow configuration apparatus 54 is illustrated in Patent No. 5,331,976, which is incorporated herein by reference. When the tow configuration apparatus 54 has a width of 70 mm, the banding jet 18 has a width (Wi) of 62.5 mm and the banding jet 30 has a width (W2) of 65 mm. When the apparatus 54 it has a width of 110, Wi is 82.5 mm and W2 is 108 mm. When the apparatus 54 has a width of 120, Wi is 102.5 mm and W2 is 118 mm. Additionally, the apparatus 54 includes a floating roller (not shown) that controls the thickness of the formed tow as it leaves the apparatus 54. The floating roller is preferably a plate that is pivotally mounted within the apparatus 54 and that is adapted to have a support coupling with the tow through the width thereof. The floating roller controls the thickness of the tow to ensure a uniform thickness thereof, and to make possible the line speed described above. The floating roller is also illustrated in the U.S. patent publications. 2003/0130638; 2003/0135176; 2003/0143324, each is incorporated herein by reference. The particle distribution apparatus 56 is located at the distal end of the tow configuration apparatus 54. The particle distribution apparatus 56 is used to distribute particles in a predetermined manner on and / or within the configured and open tow, and it will be described in more detail below. The particles include particularly SAP, but also include other solid materials, such as adhesives, fragrances, wood pulp, deodorants, antimicrobial agents, and the like. The particle distribution apparatus 56 is further described in the U.S. patent publications. Nos. 2003/0130638; 2003/0132762; 2003/0135176; and 2003/0143324, each is incorporated herein by reference. The winding apparatus 60 is used to sandwich the configured tow and loaded with particles between two layers (eg woven, non-woven and permeable and non-permeable films). The apparatus 60 is conventional and driven. The stratum 100 coming from the unwinding apparatus 22 is fed through a plurality of guide rollers 106 and passes through an adhesive applicator 64, towards a vacuum apparatus 58. The adhesive applicator 64 can be any adhesive applicator, but preferably it is a hot melt adhesive applicator. The vacuum applicator 58 is coupled to a vacuum source 104 (see Figure 4) and can be any suitable vacuum apparatus, such as a vacuum drum or a vacuum table (see also: U.S. Patent Publication No. 2003 / 0134559 which is incorporated herein by reference). The vacuum pressures vary from 7.62 - 15.24 cm of water, preferably 12.7 cm of water. The vacuum drum or vacuum table is preferably driven. The strata 102 from the unwinding apparatus 66 is fed through a plurality of guide rollers 108 and passes through another adhesive applicator 64 towards the vacuum apparatus 58. In the vacuum apparatus 58, the layers 100 and 102 intersperse the tow charged with particles and configured. The stratum 102 is pressed into the other layers by an application roller 110. The application roller 110 may include a channel cavity 114 (see Figure 5) to configure the absorbent composite 112 in a predetermined form (eg, clockwise). of sand, rectangular, etc.) and / or to press one against the other of the layers to seal them. Then, the absorbent composite 112 can be attracted to a winding apparatus 60, or it can be fed directly to a machine for making an absorbent garment. The speed of the line, measured in the vacuum drum 58, is preferably more than 190 m / min, preferably more than 225 m / min, and more preferably more than 250 m / min. The maximum line speed is approximately 300 m / min. The ratio of the speed of the tow leaving the cabinet 38 to the speed of the line in the vacuum drum 58 is more than 1 and less than 3, preferably between 1.8 to 3.0, and more preferably about 2.4. This allows the tow to accumulate in the tow configuration apparatus 54. Additionally, the line speed can be used to control the particle distribution apparatus 56. Coupling the line speed to the apparatus 56 minimizes the loss of particles (for example SAP) during the ascent or descent of the apparatus 10.

Additionally, static elimination devices (not shown) can be placed in the apparatus 10 adjacent to the tow band to decrease the static charges that may accumulate in the tow band. The placement of these devices is within the domain of the art. Also, the driven rollers are preferably coupled or controlled (not shown) in a conventional manner to facilitate starting, stopping, and varying the line speeds during operation. In Figure 3, cabinet 38 is shown in greater detail. The tow 14 before entering the cabinet 38 is attached to the guide rollers 76. The guide rollers 76 can be opened and closed by means of an opening mechanism 78. The guide rollers 76 have a diameter of 50 mm and exert a pressure of press that varies from 0.5-5 bar preferably 2-2.5 bar (using a cylinder of 2698 cm). The cabinet 38 includes a door 70 which is secured to the rest of the cabinet by means of hinges 72 and which can be secured by a latch 74. The cabinet 38 encloses the de-registration apparatus 40 and avoids contaminants, such as adhesives from the adhesive applicator. 64 so they do not soil the surface of the rollers. Fouling of the surfaces can cause adhesion of the tow to the rollers. The cabinet 38 is provided with an air nozzle 80 which is used to provide a positive pressure inside the cabinet 38 so that contaminants can not enter. The positive pressure can vary from 0.0070 - 0.0703 kg / cm2 gauge, preferably from 0.0175 - 0.0351 kg / cm2 gauge.

Referring to FIGS. 4, 5 and 6, the operation of the particle dispensing apparatus 26 is illustrated in greater detail. The particle distribution apparatus 56 is preferably a vibratory feeder. At the bottom of a hopper is a cleaning valve 90 and an engine 92 drives the feeder. The particles vibrate through a hole defined, in part, by a depression 94 where they are deposited on the open tow 98. The particles, when they are SAP, can be fed at speeds of 1 - 25 kg / min, preferably from 5 - 13.5 kg / min, assuming the formation of the garment of 500 - 900 kg / min with 10 -15 g / garment. The particles 96 and the formed tow 98 are held in place by the vacuum apparatus 58 (a rotating vacuum drum is shown), while the strata 100 and 102 are applied thereto. The layers 100 and 102 are guided to the vacuum apparatus 58 by means of rollers 106 and 108 respectively. The adhesive coming from the applicators 64 preferably applies to the layers before the arrival to the vacuum apparatus 58. When the layers interspersed the charged particles and the configured tow, in the vacuum apparatus 58, the application roller 110 presses the composite material to seal it, preferably sealing the side edges of the layers together. Then, the absorbent composite 112 is wound or directed to a subsequent operation of manufacturing the absorbent garment.

The distribution of the particles is controlled, in part by an orifice 118, of Figure 6a-6d. The orifice 118 is defined by the depression 94 and the plate 116 that can be moved to open and close the hole. In figure 6a-6d, four possible configurations for the hole 118 are illustrated. In hole 118 'of figure 6a, it illustrates a hole with a rectangular shape. The hole 118"of Figure 6b illustrates a hole with a triangular shape The orifice 118 '" of Figure 6c illustrates a hole with an arched shape. The hole 118"" of FIG. 6d illustrates a hole in the shape of a saw or toothed. Of course, other configurations of the hole will be apparent to those skilled in the art. The present invention may be represented in other ways without departing from the spirit and essential attributes thereof and, therefore, reference should be made to the appended claims, rather than the foregoing specification, as indicated by the scope of the invention.

Claims (34)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for making an absorbent composite material from a continuous tow comprising the steps of: dispersing a pleated tow; unregistering the pleated tow using at least two pairs of rollers, each pair of rollers having a metal face roller and a rubber face roller and the metal face rollers are arranged in the opposite manner around the tow; configure the unregistered tow; and distribute a particulate material on the configured tow.

2. The method according to claim 1, further characterized in that said rollers with metal face are smooth, grooved, threaded, textured or combinations thereof.

3. The method according to claim 1, further characterized in that said roller with rubber face is smooth.

4. The method according to claim 1, further characterized in that said pair of rollers are vertically aligned, one on top of the other.

5. The method according to claim 1, further characterized in that said roller pair (Ss) rotates faster than the other pair of rollers (Sf).

6. - The method according to claim 5, further characterized in that a speed ratio (S Ss) is on the scale of 1 < Sf / Ss < 2. The method according to claim 6, further characterized in that the speed ratio (Sf / Ss) is in the scale of 1.1 < Sf / Ss < 1.

7.

8. The method according to claim 1, further characterized by additionally comprising configuring the deregulated tow to a substantially rectangular cross section.

9. The method according to claim 1, further characterized in that it comprises additionally applying a liquid to the tow.

10. An apparatus for making an absorbent composite material from a continuous tow comprising the steps of: means for dispersing a pleated tow; means for unregistering the pleated tow using at least two pairs of rollers, each pair of rollers having a metal face roller and a rubber face roller and the metal face rollers are disposed in the opposite manner around the tow; means for configuring the deregulated tow; and means for distributing a particulate material on the configured tow.

11. The apparatus according to claim 10, further characterized in that said rollers with metal face are smooth, grooved, threaded, textured or combinations thereof.

12. - The apparatus according to claim 10, further characterized in that said roller with rubber face is smooth.

13. The apparatus according to claim 10, further characterized in that said pair of rollers are vertically aligned, one on top of the other.

14. The apparatus according to claim 10, further characterized in that said roller pair (Ss) rotates faster than the other pair of rollers (Sf).

15. The apparatus according to claim 14, further characterized in that a speed ratio (Sf / Ss) is on the scale of 1 < Sf / Ss < 2.

The apparatus according to claim 15, further characterized in that the speed ratio (Sf / Ss) is in the scale of 1.1 < Sf / Ss < 1.7.

17. The apparatus according to claim 10, further characterized in that it further comprises means for configuring the deregistered tow to a substantially rectangular cross section.

18. The apparatus according to claim 10, further characterized in that it additionally comprises means for applying a liquid to the tow.

19. A method for making an absorbent composite material from a continuous tow comprising the steps of: dispersing a pleated tow; unregister pleated tow using at least two pairs of rollers, each pair of rollers has a metal-faced roller and a rubber-faced roller and said pairs of rollers are vertically aligned, one on top of the other or at any angle between the vertical alignment or horizontal alignment, but not including horizontal alignment; configure the unregistered tow; and distribute a particulate material on the configured tow.

20. The method according to claim 19, further characterized in that said rollers with metal face are smooth, grooved, threaded, textured or combinations thereof.

21. The method according to claim 19, further characterized in that said roller with rubber face is smooth.

22. The method according to claim 19, further characterized in that said roller pair (Ss) rotates faster than the other pair of rollers (Sf).

23. The method according to claim 22, further characterized in that a speed ratio (Sf / Ss) is on the scale of 1 < Sf / Ss < 2.

The method according to claim 23, further characterized in that the speed ratio (Sf / Ss) is in the scale of 1.1 < Sf / Ss < 1.7.

25. - The method according to claim 19, further characterized in that it further comprises configuring the deregistered tow to a substantially rectangular cross section.

26. The method according to claim 19, further characterized in that it comprises additionally applying a liquid to the tow.

27. An apparatus for making an absorbent composite material from a continuous tow comprising the steps of: means for dispersing a pleated tow; means for unregistering the pleated tow using at least two pairs of rollers, each pair of rollers having a roller with a metal face and a roller with a rubber face, and said pairs of rollers being vertically aligned one over the other or at any angle between vertical alignment and horizontal alignment, but not including horizontal alignment; means for configuring the deregulated tow; and means for distributing a particulate material on the configured tow.

28. The apparatus according to claim 27, further characterized in that said rollers with metal face are smooth, grooved, threaded, textured or combinations thereof.

29. The apparatus according to claim 27, further characterized in that said roller with rubber face is smooth.

30. The apparatus according to claim 27, further characterized in that said roller pair (Ss) rotates faster than the other pair of rollers (Sf).

31. - The apparatus according to claim 30, further characterized in that a speed ratio (Sf / Ss) is in the scale of 1 < Sf / Ss < 2.

The apparatus according to claim 31, further characterized in that the speed ratio (Sf / Ss) is in the scale of 1.1 < Sf / Ss < 1.7.

33. The apparatus according to claim 27, further characterized in that it further comprises means for configuring the deregulated tow to a substantially rectangular cross section.

34. The apparatus according to claim 27, further characterized in that it further comprises means for applying a liquid to the tow.