Variable surface winding stretching for winding nonwoven webs

Abstract

A method of manufacturing a nonwoven material, the method comprising: feeding a nonwoven web through a winding drum and onto a core; operating the winding drum to wind the nonwoven web around the core to form a roll of the nonwoven web; and controlling the speed of the winding drum by varying the stretching while winding the nonwoven web onto the core, where the stretching is periodic: i) increasing a first magnitude, and ii) subsequently decreasing a second magnitude, where the second magnitude is less than the first magnitude, and where the periodic increasing and subsequent decreasing of the stretching are repeated, where the second magnitude is less than the first magnitude, and where the second magnitude is less than the first magnitude. Until the roll reaches a threshold diameter.

Description

Background Technology

[0001] Nonwoven fiber webs are sheet-like structures composed of randomly or semi-randomly arranged fibers or filaments bonded together mechanically, chemically, or thermally. Unlike traditional woven or knitted textiles, nonwoven fiber webs are manufactured by directly forming a web of fibers or filaments and then bonding them together without interlacing or knitting. Co-shaped nonwoven fiber webs, or “co-shaped materials,” are a form of nonwoven fiber web that is a composite of two or more materials, typically including a mixture or stabilizing matrix of thermoplastic fibers and a second material. Examples of the second material include absorbent fibrous organic materials (e.g., wood pulp), non-wood pulps (e.g., cotton, rayon, recycled paper, and pulp fluff), superabsorbent materials (e.g., superabsorbent granules and fibers), inorganic absorbent materials, treated polymer short fibers, and other materials (e.g., nonabsorbent short fibers, nonabsorbent granules, etc.). In some cases, co-shaped nonwoven fiber webs may contain absorbent materials (e.g., pulp fibers) and can be used in a variety of applications, including wet wipes.

[0002] In the production process, co-forming materials are typically wound into large rolls for storage and transport. For example, these rolls can be transported to manufacturing lines for unwinding and packaging to produce various products, such as wet wipes (e.g., rinseable wet wipes). Due to the winding process during production, the variability in the thickness of the co-forming material (e.g., the thickness of the co-formed nonwoven fiber web) can cause significant problems in downstream product production (e.g., “conversion processing”). For instance, variability in the thickness of the entire roll of co-forming material can lead to undesirable uniformity between end-user products, such as wet wipes. Furthermore, variability in the thickness of the entire roll of co-forming material in wet wipe production can cause stacker failures, paper jams in bag packaging machines, cover misalignment, and many other problems in various co-forming material conversion processing equipment. These and other problems caused by variability in co-forming material thickness result in waste, delays, and potentially introduce safety hazards due to increased human-machine interaction (e.g., increased roll change frequency, correction or removal of paper jams, etc.). Summary of the Invention

[0003] One embodiment of this disclosure is a method of manufacturing a nonwoven material, the method comprising: feeding a nonwoven fiber web through a winding drum and onto a core; operating the winding drum to wind the nonwoven fiber web around the core to form a roll of the nonwoven fiber web; and controlling the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first value, and ii) subsequently decreases by a second value, wherein the second value is less than the first value, and wherein the periodic increase and subsequent decrease of the tension is repeated until the roll reaches a threshold diameter.

[0004] Another embodiment of this disclosure is a controller for a machine including a winding drum for winding a nonwoven fiber web onto a core to form a roll. The controller includes: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the controller to: operate the winding drum to wind the nonwoven fiber web around the core to form the roll; and control the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first value, and ii) subsequently decreases by a second value, wherein the second value is less than the first value, wherein the periodic increase and subsequent decrease of the tension is repeated until the roll reaches a threshold diameter.

[0005] Another embodiment of this disclosure is a system for producing rolls of nonwoven fiber webs, the system comprising: a winding drum for winding the nonwoven fiber web onto a core to form the roll; and a controller that operates the winding drum to control the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first amount, and ii) subsequently decreases by a second amount, wherein the second amount is less than the first amount, such that for each periodic increase and decrease of the tension, the tension of the winding drum is higher after the decrease of the second amount than before the increase of the first amount.

[0006] Additional features will be set forth in part in the description below, or may be learned through practice. These features will be realized and obtained by means of the elements and combinations particularly pointed out in the appended claims. It should be understood that, as protected by the claims, the foregoing general description and the following detailed description are merely exemplary and illustrative, and not restrictive. Attached Figure Description

[0007] Figure 1 This is a diagram of an example method for forming a co-shaped nonwoven fiber web according to some embodiments.

[0008] Figure 2 This is a diagram of a surface winding machine configured to wind a nonwoven fiber web, according to some embodiments.

[0009] Figure 3 This is a diagram illustrating the height variability of a laminated nonwoven fiber mesh sheet according to some embodiments.

[0010] Figure 4A This is a graph comparing the variability of stack height in sheet stacks produced from rolls of nonwoven fiber webs wound with constant tension, according to some implementation methods.

[0011] Figure 4BThis is a graph comparing the variability of stack height in sheet stacks produced from rolls of nonwoven fiber webs using variable stretch winding, according to some embodiments.

[0012] Figure 5 This is a block diagram of a system for producing rolls of nonwoven fiber webs according to some embodiments.

[0013] Figure 6 It is a diagram of a step waveform stretching curve for a surface winding machine according to some embodiments.

[0014] Figure 7 It is based on some implementation methods Figure 6 A detailed view of the step waveform stretch curve.

[0015] Figure 8 This is a process flow diagram for producing rolls of nonwoven fiber webs according to some implementation methods.

[0016] Figure 9 It is a process flow diagram of a surface winding machine that is variably controlled based on a step waveform stretching curve, according to some implementation methods.

[0017] Figure 10A This is a schematic diagram of an apparatus and process for converting nonwoven materials into sheet laminates, according to some embodiments.

[0018] Figure 10B It is based on some implementation methods Figure 10A An enlarged side view of a portion of the device shown.

[0019] Figure 10C It is based on some implementation methods Figure 10A An enlarged front view of a portion of the device shown.

[0020] Figure 11A This is a perspective view of an example dispensing container for sheet stacks produced from nonwoven materials, according to some embodiments.

[0021] Figure 11B It is based on some implementation methods Figure 11A The example shown assigns a perspective view of a container, where the container is open.

[0022] Figure 12 This is another graph, according to some embodiments, comparing the variability of stack height in sheet stacks produced from rolls of nonwoven fiber webs wound with constant and variable tension.

[0023] Figure 13 It is a graph comparing the rate of change of average clip height in a stack of sheets produced from rolls of nonwoven fiber webs wound with constant and variable tension, according to some implementation methods.

[0024] The various objects, aspects, and features of this disclosure will become more apparent and better understood through detailed description taken in conjunction with the accompanying drawings, wherein the same reference numerals always identify corresponding elements. In the drawings, the same reference numerals generally denote the same, functionally similar, and / or structurally similar elements. Detailed Implementation

[0025] Referring generally to the accompanying drawings, methods, systems, and apparatuses for winding nonwoven fiber webs into rolls according to various embodiments are illustrated. Specifically, a variable stretch winding method and related systems and apparatus are described, which addresses the variability in the thickness of nonwoven fiber webs, such as that caused by winding via a surface winding machine. While this description is primarily directed to co-formed nonwoven fiber webs, it should be understood that the disclosed methods, systems, and apparatuses can be used to wind any type of nonwoven material into rolls. Therefore, the following disclosure is not intended to be limited to co-formed nonwoven fiber webs.

[0026] The disclosed methods typically involve periodically increasing and subsequently decreasing the stretch of the surface winder (e.g., by varying the speed of the winding drum) to increase and decrease the tension on the co-formed nonwoven web wound around the core, respectively. In some embodiments, for each periodic increase and decrease, the amount of increase in stretch is greater than the amount of decrease. When plotted, the disclosed methods typically produce a positively sloping "sine wave" or "stepped" winding curve, providing a compression release layer every few inches of roll diameter. This produces a cushioning effect, providing a more constant overall roll thickness for the co-formed nonwoven web by preventing each layer of the roll from compressing all the layers beneath it as the roll diameter expands. In some embodiments, the method is implemented via a controller that controls the speed of the winding drum of the surface winder.

[0027] nonwoven fiber web

[0028] As used herein, the term "nonwoven web" generally refers to a web of fibers or threads with a structure of individual fibers or threads that are interwoven, but in a manner that is not as clearly discernible as knitted fabrics. Examples of suitable nonwoven fabrics or webs include, but are not limited to, meltblown webs, spunbond webs, bonded carded webs, air-laid webs, co-formed webs, and hydroentangled webs.

[0029] As used herein, the term "meltblown fiber web" generally refers to a nonwoven fiber web formed by a process in which molten thermoplastic material is extruded as molten fibers through multiple fine, typically circular, die capillaries into a converging high-speed gas (e.g., air) stream. This high-speed gas stream draws the fibers of the molten thermoplastic material to reduce their diameter, which can be down to the microfiber diameter. The meltblown fibers are then carried by the high-speed gas stream and deposited onto a collection surface to form a fiber web of randomly dispersed meltblown fibers. This method is disclosed, for example, in U.S. Patent No. 3,849,241 to Butin et al. Generally, the meltblown fibers can be substantially continuous or discontinuous microfibers, typically less than 10 micrometers in diameter, and are generally sticky when deposited onto a collection surface.

[0030] As used herein, the term "spunbond web" generally refers to a web containing small-diameter, substantially continuous fibers. Fibers are formed by extruding molten thermoplastic material from multiple fine, typically circular capillaries in a spinneret, and then rapidly reducing the diameter of the extruded fibers through, for example, traction stretching and / or other well-known spunbonding mechanisms. The preparation of spunbond fiber webs is described and illustrated in, for example, U.S. Patent No. 4,340,563 to Appel et al., U.S. Patent No. 3,692,618 to Dorschner et al., U.S. Patent No. 3,802,817 to Matsuki et al., U.S. Patent No. 3,338,992 to Kinney, U.S. Patent No. 3,341,394 to Kinney, U.S. Patent No. 3,502,763 to Hartman, U.S. Patent No. 3,502,538 to Levy, U.S. Patent No. 3,542,615 to Dobo et al., and U.S. Patent No. 5,382,400 to Pike et al. Spunbond fibers are generally non-sticky when deposited onto a collection surface. Spunbond fibers can sometimes have a diameter of less than about 40 micrometers, and are typically between about 5 micrometers and about 20 micrometers.

[0031] The synthetic fibers used in co-formed nonwoven fiber webs can be formed from a variety of different thermoplastic polymers known in the art, such as polyolefins (e.g., ethylene polymers, propylene polymers, polybutene, etc.); polytetrafluoroethylene; polyesters (e.g., polyethylene terephthalate, polylactic acid, etc.); polyvinyl acetate; polyvinyl chloride; polyvinyl butyral; acrylic resins (e.g., polyacrylate, polymethacrylate, etc.); polyamides (e.g., nylon); polyvinyl chloride; polyvinylidene chloride; polystyrene; polyvinyl alcohol; polyurethane; etc., and mixtures of various polymers. Because many synthetic thermoplastic fibers are inherently hydrophobic (i.e., non-wetting), such fibers can be optionally made more hydrophilic (i.e., wettable) by treating them with a surfactant solution before, during, and / or after the formation of the fiber web. Other known methods for increasing wettability can also be used, such as those described in U.S. Patent No. 5,057,361 to Sayovitz et al.

[0032] Synthetic fibers can be monocomponent or multicomponent. Monocomponent fibers are typically formed from polymers or polymer blends extruded from a single extruder. Multicomponent fibers are typically formed from two or more polymers (e.g., bicomponent fibers) extruded from separate extruders. The polymers can be arranged in different regions at substantially constant positions across the fiber cross-section. The components can be arranged in any desired configuration, such as sheath-core, side-by-side, disc, island, three-island, bullseye, or various other arrangements known in the art. Various methods for forming multicomponent fibers are described in U.S. Patent No. 4,789,592 to Taniguchi et al., U.S. Patent No. 5,336,552 to Strack et al., U.S. Patent No. 5,108,820 to Kaneko et al., U.S. Patent No. 4,795,668 to Kruege et al., U.S. Patent No. 5,382,400 to Pike et al., U.S. Patent No. 5,336,552 to Strack et al., and U.S. Patent No. 6,200,669 to Mamon et al. Multicomponent fibers with various irregular shapes can also be formed, as described in U.S. Patent No. 5,277,976 to Hogle et al., U.S. Patent No. 5,162,074 to Hills, U.S. Patent No. 5,466,410 to Hills, U.S. Patent No. 5,069,970 to Largman et al., and U.S. Patent No. 5,057,368 to Largman et al.

[0033] In some embodiments, synthetic fibers are formed using various known processes. For example, the fibers may include spunbond fibers, meltblown fibers, and combinations thereof. Regarding meltblown fibers, the melt flow rate of the thermoplastic composition used to form the fibers can be selected within a range to optimize the properties of the resulting fibers. The melt flow rate is the weight (in grams) of polymer that can be forced through an extruder orifice (0.0825 inches in diameter) when subjected to a force of 2160 grams over 10 minutes at 230°C. Generally, the melt flow rate should be high enough to improve melt processability, but not so high as to adversely interfere with the ability of the fiber web to laminate to the porous membrane in the desired manner. Therefore, in most embodiments of this disclosure, the melt flow rate of the thermoplastic composition used to form the synthetic fibers is from about 200 g / 10 min to about 6000 g / 10 min, in some embodiments from about 300 g / 10 min to about 3000 g / 10 min, and in some embodiments from about 400 g / 10 min to about 1500 g / 10 min, as measured at 230°C with a load of 2160 g according to ASTM test method D1238-E.

[0034] Any absorbent material can generally be used in co-formed nonwoven fiber webs, such as absorbent fibers, granules, etc. In one embodiment, the absorbent material includes fibers formed by various pulping processes, such as kraft pulp, sulfite pulp, thermomechanical pulp, etc. The pulp fibers may include softwood fibers with an average fiber length greater than 1 mm, particularly about 2 mm to 5 mm, based on a length-weighted average. Such softwood fibers may include, but are not limited to, northern softwood, southern softwood, redwood, red cedar, hemlock, pine (e.g., southern pine), spruce (e.g., black spruce), combinations thereof, etc. Exemplary commercially available pulp fibers suitable for this disclosure include pulp fibers purchased under the name "Weyco CF-405" from Weyerhaeuser Co., Federal Way, Washington. Hardwood fibers, such as eucalyptus, maple, birch, aspen, etc., may also be used. In some cases, eucalyptus fibers may be particularly needed to increase the softness of the fiber web. Eucalyptus fibers can also enhance brightness, increase opacity, and alter the pore structure of the fiber web to increase its wicking capacity. Furthermore, secondary fibers obtained from recycled materials, such as pulp from sources like newsprint, recycled cardboard, and office waste, can be used if desired. Other natural fibers, such as abaca, Indian grass, milkweed, and pineapple leaf, can also be used in this disclosure. Additionally, synthetic fibers may be used in some cases.

[0035] Besides or in combination with pulp fibers, absorbent materials may also include superabsorbents in the form of fibers, granules, gels, etc. Generally, superabsorbents are water-swellable materials capable of absorbing at least about 20 times their weight, and in some cases at least about 30 times their weight, of water in an aqueous solution containing 0.9% sodium chloride. Superabsorbents can be formed from natural, synthetic, and modified natural polymers and materials. Examples of synthetic superabsorbent polymers include alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamide), polyvinyl ether, copolymers of maleic anhydride with vinyl ethers and α-olefins, poly(vinylpyrrolidone), poly(vinylmorpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. Additionally, superabsorbents include natural and modified natural polymers such as hydrolyzed acrylonitrile-grafted starch, acrylic acid-grafted starch, methylcellulose, chitosan, carboxymethyl cellulose, hydroxypropyl cellulose, and natural gums such as alginate, xanthan gum, locust bean gum, etc. Mixtures of natural and wholly or partially synthetic superabsorbent polymers may also be used in this disclosure. Particularly suitable superabsorbent polymers are HYSORB 8800 AD (BASF, Charlotte, NC) and FAVOR SXM 9300 (Degussa Superabsorber, Greensboro, NC).

[0036] The absorbent material typically constitutes about 20% to about 95% by weight of the composite matrix, in some embodiments about 40% to about 90% by weight, and in some embodiments about 60% to about 85% by weight. Similarly, synthetic fibers may constitute about 1% to about 70% by weight of the composite matrix, in some embodiments about 4% to about 60% by weight, and in some embodiments about 5% to about 50% by weight. The co-formed fiber web can be formed using a variety of different techniques known in the art.

[0037] See Figure 1Figure 10 illustrates an example apparatus 10 for forming a co-shaped nonwoven fiber web according to some embodiments. Generally, apparatus 10 employs at least one meltblown die (e.g., two) arranged near a chute through which absorbent material is added during fiber web formation. As shown, apparatus 10 may include granule hoppers 12 or 12' of extruders 14 or 14', into which a thermoplastic composition is introduced to form the synthetic fibers of the fiber web. In some embodiments, extruders 14 and 14' each have an extrusion screw (not shown) driven by a conventional drive motor (not shown). As the thermoplastic composition advances through extruders 14 and 14', the composition is gradually heated to a molten state due to the rotation of the extrusion screw by the drive motor. Heating can be performed in multiple discrete steps, wherein the temperature of the thermoplastic composition gradually increases as it advances toward the discrete heating zones of extruders 14 and 14' towards the two meltblown dies 16 and 18, respectively. Meltblown dies 16 and 18 can be another heating zone in which the temperature of the thermoplastic composition is maintained at a high level for extrusion.

[0038] When using two or more meltblown dies, as described above, it should be understood that the fibers produced by each die can be of different types. That is, one or more of the size, shape, or polymer composition may differ, and furthermore, the fibers may be single-component or multi-component fibers. For example, larger fibers may be produced by the first meltblown die, such as fibers with an average diameter of about 10 micrometers or greater, about 15 micrometers or greater in some embodiments, and about 20 to about 50 micrometers in some embodiments, while smaller fibers may be produced by the second die, such as fibers with an average diameter of about 10 micrometers or less, about 7 micrometers or less in some embodiments, and about 2 to about 6 micrometers in some embodiments. Furthermore, it may be desirable for each die to extrude approximately the same amount of polymer, such that the relative percentage of the basis weight of the co-shaped nonwoven fiber web material produced by each meltblown die is substantially the same.

[0039] Alternatively, it may be desirable to skew the relative basis weight production, such that one or more dies are responsible for producing the majority of the co-formed fiber web (by basis weight). As a concrete example, for a meltblown nonwoven fiber web material with a basis weight of 1.0 oz / y² or “osy” (34 g / m² or “gsm”), it may be desirable for the first meltblown die to produce approximately 30% of the basis weight of the meltblown nonwoven fiber web material, while one or more subsequent meltblown dies produce the remaining 70% of the basis weight. Generally, the total basis weight of the co-formed nonwoven fiber web is approximately 10 gsm to approximately 350 gsm, more specifically approximately 17 gsm to approximately 200 gsm, and even more specifically approximately 25 gsm to approximately 150 gsm.

[0040] Each meltblown die 16 and 18 is configured such that the two decaying gas streams of each die converge to form a single gas stream that entrains and thins the melt line 20 as it exits the orifice or aperture 24 in each meltblown die. The melt line 20 is formed as a fiber, or, depending on the degree of thinning, as a small-diameter microfiber typically smaller than the diameter of the orifice 24. Thus, each meltblown die 16 and 18 has a corresponding single gas stream 26 and 28 containing the entrained thermoplastic polymer fibers. The polymer fiber-containing gas streams 26 and 28 are arranged to converge at the impact zone 30. Typically, the meltblown dies 16 and 18 are arranged at an angle relative to the forming surface, as described in U.S. Patents 5,508,102 and 5,350,624 to Georger et al. For example, the meltblown dies 16 and 18 may be angularly oriented from a plane tangent to both dies 16 and 18. Typically, each die 16 and 18 is positioned at an angle ranging from about 30 degrees (°) to about 75°, in some embodiments from about 35° to about 60°, and in some embodiments from about 45° to about 55°. Dies 16 and 18 may be oriented at the same or different angles. In fact, by oriented one die at an angle different from that of the other die, the texture of the co-formed fiber web can be enhanced.

[0041] Absorbent material 32 (e.g., pulp fiber) is added to the two gas streams 26 and 28 of the thermoplastic polymer fiber 20, and also at the impact zone 30. The introduction of absorbent material 32 into the two gas streams 26 and 28 of the thermoplastic polymer fiber 20 is ideally incremental. This is achieved by incorporating a second gas stream 34 containing absorbent material 32 between the two gas streams 26 and 28 of the thermoplastic polymer fiber 20, such that all three gas streams converge in a controlled manner. Because the meltblown fibers 20 remain relatively tacky and semi-molten after forming, they can simultaneously adhere to and entangle with the absorbent material 32 upon contact, thereby forming a cohesive nonwoven structure.

[0042] Any conventional equipment can be used to supply the absorbent material. In the illustrated embodiment, for example, a pickup roller 36 with a plurality of teeth 38 is provided, which are adapted to separate the pad or wadding 40 of absorbent material into individual fibers. In use, the sheet or pad 40 is fed into the pickup roller 36 through the roller assembly 42. After the teeth 38 of the pickup roller 36 separate the pad into individual fibers, they are conveyed through nozzles 44 toward a flow of thermoplastic polymer fibers. A housing 46 surrounds the pickup roller 36 and provides a channel or gap 48 between the housing 46 and the surface of the teeth 38 of the pickup roller 36. Gas (e.g., air) is supplied through a gas conduit 50 to the channel or gap 46 between the surface of the pickup roller 36 and the housing 48. The gas conduit 50 may enter the channel or gap 46 at the junction 52 of the nozzles 44 and the gap 48. The gas is supplied in sufficient quantity to serve as a medium for conveying the absorbent material 32 through the nozzles 44. The gas supplied from the conduit 50 also helps to remove any remaining absorbent material 32 from the teeth 38 of the pickup roller 36. The gas can be supplied by any conventional device such as a blower (not shown).

[0043] The absorbent material 32 is typically conveyed through the nozzle 44 at approximately the speed at which it exits the teeth 38 of the pick-up roller 36. In other words, the absorbent material 32 maintains its speed in both magnitude and direction from the point of exit from the teeth 38 of the pick-up roller 36 as it exits and enters the nozzle 44. This arrangement is discussed in more detail in U.S. Patent No. 4,100,324 to Anderson et al. If desired, the speed of the second gas flow 34 can be adjusted to obtain co-formed structures with different properties. For example, when the speed of the second gas flow 34 is adjusted to be greater than the speed of each gas flow 26 and 28 when the thermoplastic polymer fibers 20 contact the impact zone 30, the absorbent material 32 is incorporated into the co-formed nonwoven fiber web in a gradient structure. That is, the absorbent material 32 has a higher concentration between the outer surfaces of the co-formed nonwoven fiber web than at the outer surface. On the other hand, when the velocity of the second gas flow 34 is less than the velocity of each gas flow 26 and 28 when the thermoplastic polymer fibers 20 are in contact with the impact zone 30, the absorbent material 32 is incorporated into the co-formed nonwoven fiber web in a substantially uniform manner. That is, the concentration of the absorbent material is substantially the same throughout the co-formed nonwoven fiber web. This is because the low-velocity flow of the absorbent material is drawn into the high-velocity flow of the thermoplastic polymer fibers to enhance turbulent mixing, which results in a uniform distribution of the absorbent material.

[0044] To convert the composite flow 56 of thermoplastic polymer fibers 20 and absorbent material 32 into a co-shaped nonwoven structure 54, a collection device can be positioned in the path of the composite flow 56. The collection device can be driven by rollers 60 and, as... Figure 1Arrow 62 indicates a rotating forming surface 58 (e.g., a belt, tube, wire, fabric, etc.). The combined flow of thermoplastic polymer fibers and absorbent material is collected as a cohesive matrix of fibers on the surface of forming surface 58 to form a co-formed nonwoven fiber web 54. If desired, a vacuum chamber (not shown) can be used to help stretch near-molten meltblown fibers onto forming surface 58. The resulting textured co-formed structure 54 is cohesive and can be removed from forming surface 58 as a self-supporting nonwoven material.

[0045] It should be understood that this disclosure is by no means limited to the embodiments described above. In an alternative embodiment, for example, first and second meltblown dies may be used, which extend substantially across the forming surface in a direction substantially transverse to the direction of movement of the forming surface. The dies may also be arranged substantially vertically, i.e., perpendicular to the forming surface, such that the resulting meltblown fibers are blown directly downwards onto the forming surface. This configuration is well known in the art and is described in more detail, for example, in U.S. Patent Application Publication No. 2007 / 0049153 by Dunbar et al. Furthermore, although the above embodiments employ multiple meltblown dies to produce fibers of different sizes, a single die may also be used. For example, an example of such a process is described in U.S. Patent Application Publication No. 2005 / 0136781 by Lassiq et al.

[0046] Nonwoven laminates can be used in a variety of articles. For example, laminates can be incorporated into "absorbent articles" that can absorb water or other fluids. Examples of absorbent articles include, but are not limited to, personal care absorbent articles such as diapers, training pants, absorbent underwear, incontinence products, feminine hygiene products (e.g., sanitary napkins), swimwear, baby wipes, glove-like wipes, etc.; medical absorbent articles such as clothing, ventilators, pads, mattresses, bandages, absorbent surgical drapes, and medical wipes; food cleaning wipes; garment articles; storage bags, etc. Materials and processes suitable for forming such articles are well known to those skilled in the art.

[0047] In one specific embodiment of this disclosure, a nonwoven laminate is used to form a wipe. The wipe may be formed entirely of the laminate, or it may contain other materials such as membranes, nonwoven fiber webs (e.g., spunbond fiber webs, meltblown fiber webs, carded fiber web materials, other co-formed fiber webs, air-laid fiber webs, etc.), paper products, etc. In one embodiment, for example, two layers of material may be attached together to form a wipe, as described in U.S. Patent Application Publication No. 2007 / 0065643 granted to Kopacz. In such embodiments, one or both of these layers may be formed by the laminate of this disclosure. In another embodiment, it may be desirable to provide a certain amount of separation between the user's hand and the wetted or saturated liquid already applied to the wipe, or, in the case where the wipe is provided as a dry wipe, to provide separation between the user's hand and any liquid spillage being cleaned up by the user. In this case, additional nonwoven fiber webs or membranes may be attached to the surface of the laminate to provide physical separation and / or provide liquid barrier properties. Additional fiber webs may also be included to increase absorbency, or for the purpose of absorbing larger liquid spills, or for providing a wipe with a large liquid capacity. When used, such additional materials may be attached to the laminate using any method known to those skilled in the art, such as by thermal lamination or adhesive lamination, or by bonding to separate materials placed in face-to-face contact. Regardless of the materials or processes used to form the wipe, the basis weight of the wipe is typically from about 20 gsm to about 200 gsm, and in some embodiments, between about 35 gsm and about 100 gsm. Lower basis weight products may be particularly suitable for use as lightweight wipes, while higher basis weight products may be more suitable for use as industrial wipes.

[0048] The wipes can be in various shapes, including but not limited to generally circular, oval, square, rectangular, or irregular shapes. Each individual wipe can be arranged in a folded configuration and stacked one on top of the other to provide a wet wipe stack. Such folding configurations are well known to those skilled in the art and include C-folds, Z-folds, quarter-folds, etc. For example, the wipes can have an unfolded length of about 2.0 cm to about 80.0 cm, and in some embodiments about 10.0 cm to about 25.0 cm. The wipes can also have an unfolded width of about 2.0 cm to about 80.0 cm, and in some embodiments about 10.0 cm to about 25.0 cm. The folded wipe stack can be placed inside a container such as a plastic bucket to provide a package of wipes for eventual sale to a consumer. Alternatively, the wipes can comprise continuous strips of material with perforations between each wipe, and can be arranged in a stack or rolled up for dispensing. Various suitable dispensers, containers, and systems for delivering wipes are described in U.S. Patent No. 5,785,179 to Buczwinski et al.; U.S. Patent No. 5,964,351 to Zander; U.S. Patent No. 6,030,331 to Zander; U.S. Patent No. 6,158,614 to Haynes et al.; U.S. Patent No. 6,269,969 to Huang et al.; U.S. Patent No. 6,269,970 to Huang et al.; and U.S. Patent No. 6,273,359 to Newman et al.

[0049] In some embodiments of this disclosure, the wipe is a “wet” or “pre-wet” wipe because it contains a liquid solution for cleaning, disinfecting, sterilizing, etc. The specific liquid solution is not critical and is described in more detail in U.S. Patent No. 6,440,437 to Krzysik et al.; U.S. Patent No. 6,028,018 to Amundson et al.; U.S. Patent No. 5,888,524 to Cole; U.S. Patent No. 5,667,635 to Win et al.; and U.S. Patent No. 5,540,332 to Kopacz et al. The amount of liquid solution used can depend on the type of wipe material used, the type of container used to store the wipe, the nature of the cleaning agent, and the intended end use of the wipe. Notably, it has been found that the laminates of this disclosure can use even lower amounts of solution than conventionally used. For example, based on the dry weight of the wipe, each wipe may contain about 100% to about 500% by weight, about 200% to about 450% by weight in some embodiments, and about 250% to about 400% by weight of liquid solution in some embodiments.

[0050] Surface winding

[0051] See now Figure 2 A figure shows a surface winding machine 200 configured to wind a nonwoven fiber web according to some embodiments. Specifically, the surface winding machine 200 can be configured to wind using the methods described above relative to... Figure 1 The co-formed nonwoven fiber web or other nonwoven fiber web, or any other type of co-formed nonwoven fiber web, is produced by the aforementioned equipment 10 and / or technology. In some embodiments, the surface winding machine 200 is part of a larger co-formed nonwoven fiber web production system, for example, including the aforementioned equipment 10 and / or technology. For example, the surface winding machine 200 may be positioned at the end of a co-formed nonwoven fiber web production line to wind the produced co-formed nonwoven fiber web into rolls for later use, for example, to be conveyed to another production line or system for manufacturing products (e.g., wipes) from the co-formed nonwoven fiber web.

[0052] Generally speaking, a surface winding machine (also known as a roll winding machine or simply a winding machine) is a machine used to wind material into a roll or spool. Specifically, a surface winding machine is configured to wind a continuous sheet or web of material (e.g., a nonwoven fiber web) into a roll in a controlled manner. When the material (e.g., a nonwoven fiber web) is wound into a roll, the material is subjected to tension or strain, which helps maintain the integrity of the wound roll and ensures proper alignment and tightness of the layers. In the context of surface winding machines, "stretch" refers to the tension or strain applied to the material wound into a roll or spool. Stretching is typically defined by a combination of factors, including but not limited to winding speed, the diameter of the wound roll, and (optionally) a tension control system, and is usually expressed as a percentage (e.g., "stretch percentage" or "% stretch"). As discussed in more detail below, surface winding machines typically operate at a constant winding speed, thereby operating with constant tension; however, this disclosure envisions a technique for controlling a surface winding machine to, for example, change the tension of a material (e.g., a nonwoven fiber web) throughout the winding process by controlling the winding speed.

[0053] As shown, a surface winding machine 200 typically includes at least one winding drum 202 for winding a co-formed nonwoven fiber web 204 onto a first core 206. The winding drum 202 is a “driven” or “powered” drum; in other words, the winding drum 202 is typically (e.g., directly, via a gear system, via a belt, etc.) coupled to a motor (e.g., an electric motor as described below), which can be controlled to rotate the winding drum 202. Specifically, the speed of the motor can be controlled to adjust the rotational speed of the winding drum 202, thereby controlling the speed at which the winding drum 202 winds the co-formed nonwoven fiber web 204 onto the first core 206. Therefore, it should be understood that controlling the rotational speed of the winding drum 202 can, in turn, be controlled by adjusting or setting the tension of the surface winding machine 200 (e.g., the tension when the co-formed nonwoven fiber web 204 is wound onto the first core 206). As discussed in more detail below, controlling the speed of the winding drum 202 can also adjust the tension on the co-formed nonwoven fiber web 204, which affects the tightness of the winding of the co-formed nonwoven fiber web 204.

[0054] During operation, the co-formed nonwoven fiber web 204 is typically guided through the winding drum 202 such that one side of the co-formed nonwoven fiber web 204 contacts a portion of the outer surface of the winding drum 202. For example, the co-formed nonwoven fiber web 204 may be guided above the top of the winding drum 202, such as... Figure 2 As shown, or below the winding drum 202. Furthermore, a portion of the outer surface of the winding drum 202 may initially contact the outer surface of the first core 206. In other words, the first core 206 may be loaded against the winding drum 202, causing the first core 206 to rotate together with the winding drum 202. As the winding drum 202 rotates against the first core 206—thus transferring rotational energy to the first core 206 to cause it to rotate—the co-formed nonwoven fiber web 204 is wound around the first core 206 to form a first roll 210, for example, due to the roll gap principle. In this respect, after the initial layer of the co-formed nonwoven fiber web 204 has been wound around the first core 206, the outer surface of the winding drum 202 may then contact the outer surface of the first roll 210 (e.g., the co-formed nonwoven fiber web 204), thus rotating against the outer surface of the first roll 210 and causing the first roll 210 to rotate in order to wind the co-formed nonwoven fiber web 204.

[0055] In some embodiments, for example, the surface winding machine 200 may include more than one winding drum in addition to the winding drum 202. Figure 2In the example, the surface winding machine 200 may include at least a second winding drum 214, also referred to as a "first position" winding drum. In some embodiments, the second winding drum 214 is also driven or powered, for example, by an electric motor. For example, the second winding drum 214 may be powered by the same motor as the winding drum 202 or by a different / separate motor. In some embodiments, the winding drum 202 rotates at least partially with the second winding drum 214. For example, the winding drum 202 may be directly connected to the second winding drum 214, via a belt or a series of belts, via a gear set, etc. Figure 2 In this example, the winding drum 202 is shown to be connected to the second winding drum 214 via a belt, such that rotation of the second winding drum 214 causes rotation of the winding drum 202, and vice versa.

[0056] In some embodiments, the surface winder 200 may include a bracket 218 for holding a first core 206. In some embodiments, the bracket 218 may hold more than one core, thereby holding more than one roll of co-formed nonwoven fiber web. As shown, for example, the surface winder 200 may include at least a second core 208 around which a second roll 212 of co-formed nonwoven fiber web 204 is wound. In some embodiments, the second roll 212 is formed before the first roll 210 and then transferred / moved away from the winding drum 202 to make room for the first core 206, thereby forming the first roll 210. In this way, the second roll 212 can be accessed without interrupting the winding of the first roll 210. For example, the second roll 212 may be removed from the surface winder 200 and transported to another location while the first roll 210 is being wound.

[0057] Constant stretch winding

[0058] As described above, the co-formed nonwoven fiber web 204 can be used in a variety of articles. For example, the co-formed nonwoven fiber web 204 can be incorporated into "absorbent articles" capable of absorbing water or other fluids (e.g., diapers, training pants, absorbent underwear, incontinence products, feminine hygiene products, etc.). In some embodiments, also as described above, the co-formed nonwoven fiber web 204 is used to produce wipes, such as wet wipes. However, as described above, when producing products downstream (e.g., "conversion processing"), the variability in the thickness of the co-formed nonwoven fiber web 204 due to the winding process, for example, of the surface winding machine 200, can cause serious problems. For example, the variability in the thickness of the roll of co-formed material in wet wipe production can lead to stacker collapse, paper jams in bag packaging machines, cover misalignment, and many other problems in various co-formed material conversion processing equipment.

[0059] Generally, the thickness of a co-formed nonwoven web (e.g., co-formed nonwoven web 204) is affected by two main variables—the weight of the co-formed nonwoven web on the roll (e.g., due to the number of layers) and the tension on the co-formed nonwoven web during winding. Typically, the winding drum of a conventional surface winder operates at a constant speed—and thus at a constant tension—ensuring that the tension on the co-formed nonwoven web is consistent throughout the winding process (e.g., on each layer of the roll). However, this can cause the inner layers of the roll (e.g., roll 210) to be compressed due to the weight of the outer layers of material, for example, when the roll reaches its full size. Therefore, the inner layers of a roll of co-formed nonwoven web are typically thinner than the outer layers. In other words, the inner layers of a roll of co-formed nonwoven web are compressed due to the weight of the outer layers, thus reducing their thickness; however, the outer layers of the roll are not affected in the same way.

[0060] Figure 3 An example graph is shown, illustrating the effect of this variability in the thickness of the co-formed nonwoven fiber web throughout the roll when the material is transformed into products such as wipes. Specifically, Figure 3 The diagram illustrates the variability in stack height across multiple stacks of a co-formed nonwoven fiber web sheet, produced (e.g., cut) (e.g., to form a wipe) from a roll of co-formed nonwoven fiber web wound at a constant stretch. In this example, the height of the stack of n sheets is typically maximum when it is made from the outer layers of a roll of co-formed nonwoven fiber web (e.g., first roll 210). In contrast, the height of the stack of n sheets of co-formed nonwoven fiber web produced from the inner layers of the roll is much shorter—approximately 0.6 inches in this example. Therefore, it should be understood that due to the variability in thickness of the co-formed nonwoven fiber web throughout the roll, stacks of co-formed nonwoven fiber web sheets made from the outer layers of the roll are typically significantly higher than stacks made from the inner layers of the roll. In other words, the co-formed nonwoven fiber web is typically thickest at the outermost layer of the roll and thinnest at the innermost layer.

[0061] Figure 4A The effect of the variability in the thickness (e.g., "whole roll thickness") of the co-formed nonwoven fiber web throughout the roll is further illustrated, showing graphs covering the stack height and roll diameter of a series of example co-formed nonwoven fiber web rolls. Specifically, Figure 4AThe figures compare the stack height and roll diameter on three example rolls of co-shaped nonwoven fiber webs produced using a constant winding stretch profile—shown as stack height data 402 and roll diameter line 404, respectively. As described herein, a “constant winding stretch profile” generally refers to a control method for the winding drum of a surface winding machine (e.g., winding drum 202 of surface winding machine 200), wherein the winding drum operates at a constant speed (e.g., corresponding to constant stretch) throughout the winding process of the roll. In other words, by Figure 4A The example rolls shown in the diagram are produced by a surface winding machine operating at constant tension throughout the entire production (e.g., winding) of each roll. Each roll is then transferred to a co-forming material conversion processing facility (e.g., a different production line / system) for producing wipe stacks (e.g., for wet wipe production), and the resulting stack height of n sheets of the co-formed nonwoven fiber web is measured.

[0062] As shown in the figure, the stack height (e.g., shown as stack height data 402) typically decreases as the roll diameter increases, which is consistent with... Figure 3 The results presented are consistent. In other words, sheets made from co-formed nonwoven fiber webs closer to the center of the roll are generally thinner than sheets made from co-formed nonwoven fiber webs closer to the outer edge of the roll. When multiple sheets are stacked, this effect is cumulative, resulting in the stack height of n sheets varying significantly depending on which part of the roll the sheets were produced from. Therefore, Figure 3 and Figure 4A This clearly demonstrates how the variability in the degree of co-formed nonwoven fiber webs, due to constant stretch winding, can ultimately affect the quality of the produced articles and / or cause numerous problems when producing various articles from rolls of co-formed nonwoven fiber webs. See below for reference. Figures 10A to 11B Additional discussion is provided on an example system for converting rolls of nonwoven fiber webs into sheet laminates.

[0063] Variable stretch winding

[0064] As described above, this disclosure generally relates to a method and related systems and apparatus that addresses the variability in the thickness of the co-shaped nonwoven fiber web due to winding by varying the stretching of a surface winder (e.g., surface winder 200) as the co-shaped nonwoven fiber web is wound into a roll. Reference is made below. Figures 5 to 9Details of the winding method are provided; however, at a high level, surface winding machines (e.g., surface winding machine 200) typically operate by periodically and repeatedly performing the following operations: i) increasing the stretch by a first amount; ii) maintaining the increased stretch until the diameter of the roll increases by a first predetermined amount; iii) decreasing the stretch by a second amount; and iv) maintaining the decreased stretch until the diameter of the roll increases by a second predetermined amount. Generally, the second amount is less than the first amount, such that both the "increased stretch" and the "decreased stretch" increase with each periodic increase / decrease of the stretch. In this document, this periodic increase and decrease in stretch may be referred to as a "variable winding stretch curve," such as... Figure 6 and Figure 7 As shown and described below.

[0065] As mentioned above Figure 2 As described herein, stretching is typically defined by a combination of factors including winding speed, roll diameter, and tension applied to the material. However, it should be understood that the roll diameter is generally variable throughout the winding process (e.g., the roll diameter increases inherently with winding), and not all surface winding machines include a variable tension adjustment system. Therefore, as described herein, stretching is typically controlled (e.g., set) by varying the winding speed of the winding drum, thereby varying the winding speed at which the material (e.g., the co-formed nonwoven web 204) is wound into a roll. Specifically, the speed of the winding drum 202 can be increased to correspondingly increase stretching, or decreased to correspondingly decrease stretching, and vice versa.

[0066] Figure 4B A graph showing the stacking height and roll diameter of a co-shaped nonwoven fiber web produced using the aforementioned variable winding stretch curve according to some embodiments is illustrated. Figure 4A The diagram is similar. Figure 4B The diagram shown was generated using three example rolls of co-shaped nonwoven material; however, Figure 4B The roll shown is wound using the aforementioned variable winding stretch curve. As illustrated, this results in a more consistent roll thickness, which in turn leads to a more consistent stack height of the produced sheets (e.g., shown as stack height data 402). In other words, the stack height of the n sheets of the co-formed nonwoven material is relatively consistent, regardless of which part of the roll the sheets are produced from (e.g., the center layer or the outer layer).

[0067] As described herein, this repetitive and periodic increase and decrease in stretch winds the co-shaped nonwoven web in a manner that imparts a compression-releasing layer per n inches within the roll to create a “buffer,” thereby providing a more constant overall roll thickness of the co-shaped nonwoven web by preventing each layer of the roll from compressing all the layers beneath it as the roll expands in diameter. Furthermore, the gradual increase in stretch (e.g., where each increase and decrease in stretch is greater than the most recent increase or decrease in stretch, respectively) results in a gradual increase in the tension of the wound co-shaped nonwoven web, as follows: Figure 6 As shown, this causes the outer layer to be wound with increased tension relative to the inner layer. (As...) Figure 4B As shown, this results in a more uniform thickness of the co-formed nonwoven web throughout the roll, because the increased tension leads to a reduction in the thickness of the co-formed nonwoven web. Therefore, the outer layers of the roll can be wound with increased tension, allowing their thickness to more closely match the inner layers of the roll, whose thickness is affected by the weight of the roll itself. In other words, the outer layers can be made thinner to more closely match the thickness of the inner layers. See below for reference. Figure 12 and 13 Additional discussion and related test results are provided regarding the variability of stack height between sheet layers produced using rolls of nonwoven fiber webs wound with constant and variable stretch profiles.

[0068] Systems and methods for variable stretch winding

[0069] See now Figure 5 A block diagram of a system 500 for producing rolls of co-formed nonwoven fiber webs according to some embodiments is shown. System 500 is shown as including a surface winding machine 200 as described above, which includes a winding drum 202 and a first core 206. As described above, the surface winding machine 200 may include a motor 216 for rotating the winding drum 202. In some embodiments, the motor 216 is an electric motor. The surface winding machine 200 may also include a bracket 218 or component for holding the first core 206, for example, during the formation of roll 210. In some embodiments, the surface winding machine 200 may also include a second roll 212 and / or a second winding drum 214, and thus may include a second bracket for holding the second core 208 during the production of the second roll 212. In some embodiments, where the surface winding machine 200 includes more than one winding drum (e.g., a second winding drum 214), the surface winding machine 200 may also include more than one motor (e.g., more than one motor 216). Alternatively, as described above, motor 216 may be configured to operate (e.g., rotate) both winding drum 202 and second winding drum 214.

[0070] In some embodiments, the surface winding machine 200 also includes a roll thickness sensor 220 for measuring the diameter of a roll (e.g., a first roll 210) of a co-formed nonwoven fiber web during production (e.g., winding). Generally, the roll thickness sensor 220 can be any suitable sensor for measuring the roll diameter. In some embodiments, the roll thickness sensor 220 is a laser sensor or similar sensor used to measure the distance between a fixed mounting point and the roll surface. Based on the distance to the roll surface, the controller 510 can calculate the roll diameter. In other embodiments, another type of sensor can be used to measure the roll diameter. Notably, the roll diameter can be measured periodically or continuously throughout the winding process.

[0071] System 500 is also shown as including a controller 510 for controlling the operation of surface winding machine 200. Specifically, controller 510 can transmit control signals to and / or receive signals / data from various components of surface winding machine 200, as described in more detail below. Controller 510 is shown as including processor 512 and memory 514. Processor 512 may be a general-purpose processor, application-specific integrated circuit (ASIC), one or more field-programmable gate arrays (FPGAs), a set of processing units, or other suitable electronic processing architecture. In some embodiments, processor 512 is configured to execute program code stored in memory 514 to cause controller 510 to perform one or more operations, as described in more detail below. In some embodiments, processor 512 and memory 514 may be communicatively connected, such as via processing circuitry, and may include computer code for performing (e.g., by processor 512) one or more processes described herein.

[0072] Memory 514 may include one or more devices (e.g., memory cells, memory devices, storage devices, etc.) for storing data and / or computer code used to perform and / or facilitate the various processes described in this disclosure. In some embodiments, memory 514 includes a tangible (e.g., non-transitory) computer-readable medium storing code or instructions executable by processor 512. Tangible computer-readable medium refers to any physical medium capable of providing data that causes controller 510 to operate in a particular manner. Examples of tangible computer-readable media may include, but are not limited to, volatile media, non-volatile media, removable media, and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Thus, memory 514 may include RAM, ROM, hard disk drive storage devices, temporary storage devices, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and / or computer instructions. Memory 514 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in this disclosure.

[0073] Although shown as separate components, it should be understood that processor 512 and / or memory 514 can be implemented using various different types and numbers of processors and memories. For example, processor 512 may represent a single processing device or multiple processing devices. Similarly, memory 514 may represent a single memory device or multiple memory devices. Additionally, in some embodiments, controller 510 may be implemented within a single computing device (e.g., a server, a enclosure, etc.). In other embodiments, controller 510 may be distributed across multiple servers or computers (e.g., it may exist in a distributed location). For example, controller 510 may include multiple distributed computing devices (e.g., multiple processors and / or memory devices) communicating with each other, cooperating to perform operations. For example, but not as a limitation, the application may be partitioned in a manner that allows for concurrent and / or parallel processing of the application's instructions. Alternatively, data processed by the application may be partitioned in a manner that allows different portions of the dataset to be processed simultaneously and / or in parallel by two or more computers.

[0074] It should also be understood that in embodiments where controller 510 is part of another computing device (e.g., a control system for a larger co-formed nonwoven fabric production line), components of controller 510 may be shared or identical with the host device. In some embodiments, controller 510 is a programmable logic controller (PLC). For example, controller 510 may be a system for controlling the production of co-formed nonwoven fiber webs (e.g., including those described above). Figure 1 and / or Figure 2The controller 510 is one of one or more PLCs that operate the various components described above. In some embodiments, the controller 510 is implemented via multiple PLCs.

[0075] The controller 510 is also shown to include a communication interface 516 that facilitates communication between the controller 510 and any external components or devices. For example, the communication interface 516 may provide means for sending and / or receiving data from a remote computing device, for example, for programming the controller 510. Therefore, the communication interface 516 may be or may include a wired or wireless communication interface (e.g., a jack, antenna, transmitter, receiver, transceiver, wired terminal, etc.) for data communication, or a combination of wired and wireless communication interfaces. In some embodiments, communication via the communication interface 516 is direct (e.g., local wired or wireless communication) or via a network (e.g., a WAN, the Internet, a cellular network, etc.). For example, the communication interface 516 may include one or more Ethernet ports for communicatively coupling the controller 510 to a network (e.g., the Internet). As another example, the communication interface 516 may include a Wi-Fi transceiver for communication via a wireless communication network. In yet another example, the communication interface 516 may include a cellular or mobile phone communication transceiver. In yet another example, the communication interface 516 may include a Universal Serial Bus (USB) connection for transmitting data to an external device.

[0076] In some embodiments, the controller 510 includes an input / output (I / O) interface 518 for transmitting signals to remote devices. In some such embodiments, the I / O interface 518 is configured to facilitate sending and receiving signals to / from components of the surface winding machine 200. Specifically, the I / O interface 518 may facilitate the transmission of control signals to the winding drum motor 216 to control the speed of the winding drum 202 and / or the second winding drum 214. Additionally, the I / O interface 518 may facilitate the reception of signals (e.g., data) from the roll thickness sensor 220 or other components of the surface winding machine 200. Therefore, the I / O interface 518 may be configured to transmit (e.g., send and / or receive) digital and / or analog signals. For example, in some embodiments, the controller 510 outputs a digital signal to control a relay for supplying / controlling power to / from the motor 216. In some implementations, controller 510 controls the speed of winding drum 202 by sending signals to and / or receiving signals from a variable frequency drive (VFD), which interprets signals from controller 510 and directly controls motor 216.

[0077] As described above, stretch is typically defined as a percentage value (e.g., "% stretch") and is determined by several factors, including winding speed. Therefore, controller 510 is typically configured to variablely adjust the stretch by controlling the speed of motor 216 based on the aforementioned variable winding stretch curve during the winding of the co-formed nonwoven web 204 into a roll. Specifically, controller 510 may periodically increase and then decrease the speed of motor 216 to correspondingly increase and then decrease the stretch in a stepped (or sinusoidal) pattern with a positive slope, such as... Figure 6 and Figure 7 As shown. In some embodiments, the variable winding stretch curve is predefined (e.g., stored in memory 514). For example, the controller 510 can be programmed (e.g., via a remote device) such that the variable winding stretch curve as described herein is stored in memory 514.

[0078] In some embodiments, the variable winding stretch curve may be stored as an array or in a lookup table. For example, the variable winding stretch curve may be stored in an array that associates (e.g., maps) roll diameter with stretch values ​​(e.g., expressed as a percentage). In some such embodiments, the array further associates the roll diameter with the winding drum speed, such that the controller 510 operates the motor 216 at a specific speed that depends on the current diameter of the roll of the co-formed nonwoven fiber web. Alternatively, in some such embodiments, the winding speed may be determined using the stretch value associated with a given roll diameter (e.g., by the controller 510), and then used to control the winding drum 202. In other embodiments, the variable winding stretch curve is stored as one or more equations for calculating stretch values ​​based on the roll diameter. For example, the controller 510 may calculate the stretch value in real time or near real time based on a measured diameter of the roll, and the stretch value may in turn be used to calculate the speed at which the winding drum 202 is operated. In some such embodiments, the roll diameter may be variable in each equation. In either case, controller 510 can be configured to monitor (e.g., periodically or continuously measure) the diameter of the roll (e.g., roll 210) throughout the winding process to determine the stretch.

[0079] As described above, the controller 510 is typically configured to periodically change the stretch, for example, by changing the speed of the winding drum 202. For example, in some embodiments, changing the speed of the winding drum 202 can be achieved by controlling the motor 216 (for each cycle) to include: i) increasing the stretch by a first amount, which in turn increases the speed of the winding drum 202; ii) maintaining the operation of the winding drum 202 at the increased speed until the diameter of the roll increases by a first predetermined amount; iii) decreasing the stretch by a second amount less than the first amount, which in turn decreases the speed of the winding drum 202; and iv) maintaining the operation of the winding drum 202 at the decreased speed until the diameter of the roll increases by a second predetermined amount. Figure 6Figure 600, according to some embodiments, illustrates this periodic increase and decrease in stretching as a positive-slope step-wave stretching curve 602. Specifically, the step-wave stretching curve 602 typically represents the stretching relative to the diameter of the roll of the produced co-shaped nonwoven fiber web (e.g., as determined by measurements from roll thickness sensor 220)—as defined based on the speed of the winding drum 202.

[0080] Figure 600 also illustrates the pressure on the co-formed nonwoven web as it is wound to form a roll—shown as the “Pressure” line 604, which represents pressure in pounds per linear inch (PLI). It can be seen that the pressure on the co-formed nonwoven web typically increases with increasing roll diameter (e.g., in a stepped pattern). For example, the initial pressure on the co-formed nonwoven web is approximately 1.8 PLI, which climbs to a final pressure of 3.0 PLI with each periodic increase / decrease in stretching. As described above, as the roll diameter increases, winding the co-formed nonwoven web according to the variable stretching curves described herein (e.g., represented by the stepped waveform stretching curve 602) imparts a compression release layer per n inches within the roll. This produces a cushioning effect, providing a more constant overall roll thickness for the co-formed nonwoven web by preventing each layer of the roll from compressing all the layers beneath it as the roll diameter expands.

[0081] Regarding the step-wave stretch curve 602, controller 510 is shown operating surface winder 200 with an initial stretch value (e.g., 101.24% stretch) until a first threshold roll diameter is reached. In the example shown, the initial stretch value is maintained until the roll reaches a diameter of approximately 14 inches. Once the first threshold roll diameter is reached, controller 510 increases the stretch by a first amount (e.g., increases to 101.99% stretch) and maintains operation at the increased stretch until the roll diameter increases by a first predetermined amount (e.g., four inches). Controller 510 then decreases the stretch by a second amount and maintains operation at the decreased stretch value until the roll diameter increases by a second predetermined amount (e.g., two inches). As described above, increasing the stretch generally corresponds to an increase in the winding drum speed 202, and decreasing the stretch generally corresponds to a decrease in the winding drum speed 202. In other words, as the stretch increases, the speed of the winding drum speed 202 increases, and as the stretch decreases, the speed of the winding drum speed 202 decreases. As shown in the figure, for each cycle, the stretch typically increases more than it decreases; therefore, the step-wave stretch curve 602 is shown as typically increasing linearly over time. For example, the controller 510 may increase the stretch by 0.75% with each periodic repetition and then decrease the stretch by 0.72%. In this way, each successive "increased stretch" and "decreased stretch" may be larger / higher than the previous "increased stretch" and "decreased stretch" (e.g., 0.03%).

[0082] In some implementations, for each periodic increase and decrease in stretching, the value of each of the first and second magnitudes remains constant. In other words, controller 510 may increase the stretch by the same amount with each periodic increase (e.g., with each repetition) and decrease the stretch by the same amount with each periodic decrease. As in the example above, controller 510 may increase the stretch by 0.75% with each periodic increase and decrease the stretch by 0.72% with each periodic decrease. Therefore, as an example, the stretching may follow a pattern of: increase of 0.75%, decrease of 0.72%, increase of 0.75%, decrease of 0.72%, ..., etc.

[0083] In other embodiments, for each periodic increase and decrease in stretching, the value of one or both of the first and second magnitudes can be different or variable. In other words, the controller 510 can increase the stretch by a different magnitude with each periodic increase (e.g., with each repetition) and decrease the stretch by a different magnitude with each periodic decrease. In this case, as an example, the stretching could follow a pattern of: increase by 0.75%, decrease by 0.72%, increase by 0.78%, decrease by 0.72%, ..., etc. Alternatively, as another example: increase by 0.75%, decrease by 0.72%, increase by 0.78%, decrease by 0.68%, ..., etc.

[0084] Figure 7 A step waveform stretch curve 602 according to some embodiments is shown in more detail. Specifically, Figure 7 A close-up view of the first three cycles of the step-wave stretch curve 602 is shown. As illustrated, each cycle of the step-wave stretch curve 602 is defined by a step rise 702, a peak period 704, a step fall 706, and a trough period 708, corresponding to an increase / decrease in stretch during that cycle. For the purposes of this discussion, each step rise 702 corresponds to a first increase in stretch, and each step fall 706 corresponds to a second decrease in stretch. Typically, the first value is greater than the second value; in other words, each step rise 702 is greater than its corresponding step fall 706.

[0085] As described herein, each step up 702 is typically associated with an increase in stretch of approximately 0.75%; however, the magnitude of each step up 702 can fall anywhere from approximately 0.02% to approximately 2%. Each step down 706 is typically associated with a decrease in stretch of approximately 0.72%; however, the magnitude of each step down 706 can fall anywhere from approximately 0.01% to approximately 2%. As mentioned, the magnitude of each step up 702 is typically greater than the magnitude of each corresponding step down 706. For example, if a step up 702 corresponds to a 0.75% increase in stretch, the magnitude of a step down 706 will be less than 0.75% (e.g., in...). Figure 7 In the example, it is 0.72%. Therefore, each peak period 704 is associated with a stretch higher than any previous peak, and each trough 708 is associated with a stretch higher than any previous trough. For example, in... Figure 7 In the figure, the first peak corresponds to a % stretch of 101.99, and the second peak corresponds to a % stretch of 102.13. Similarly, the first valley corresponds to a % stretch of 101.38, and the second peak corresponds to a % stretch of 102.18.

[0086] In some embodiments, tension (e.g., of the winding drum 202) is maintained at each corresponding peak period 704 or trough period 708 until the diameter of the roll has increased by a predetermined amount. Specifically, tension may be maintained at each corresponding peak period 704 until the diameter of the roll increases by a first amount, and tension may be maintained at each corresponding trough period 708 until the diameter of the roll increases by a second amount. Generally, the first amount (e.g., the tension maintained during the peak period) differs from the second amount (e.g., the tension maintained during the trough period); however, in some embodiments, the first amount and the second amount may be the same.

[0087] exist Figure 7 In the example, stretching is maintained at each corresponding peak period 704 and trough period 708 until the roll diameter increases by four inches and two inches, respectively. However, it should be understood that this disclosure is not intended to be limiting in this respect. Rather, each peak period 704 and trough period 708 may be maintained until the roll diameter increases by any other predetermined amount. Alternatively, in some embodiments, stretching is maintained at each corresponding peak period 704 and trough period 708 for a predetermined period of time (e.g., opposite to maintenance based on roll diameter). As shown, in some embodiments, stretching at each peak period 704 is maintained for a longer period than stretching at each corresponding trough period 708 (e.g., based on time or roll diameter); however, in various other embodiments, each peak period 704 and trough period 708 may be the same (e.g., when...). Figure 7When drawn in the diagram, the peak periods 704 and 708 may have the same width, or each peak period 704 may be shorter than its corresponding trough period 708. Furthermore, it should be understood that the width of each peak period 704 and trough period 708 may vary throughout the production of the rolls of the co-formed nonwoven fiber web.

[0088] See now Figure 8 A flowchart of a method 800 for producing rolls of nonwoven fiber webs according to some embodiments is shown. Specifically, in some embodiments, process 800 can be used to produce rolls of co-formed nonwoven fiber webs, for example, as part of a process for manufacturing co-formed nonwoven fiber webs. In some embodiments, process 800 is partially implemented by controller 510, as described above. However, it should be understood that process 800 can be implemented by other means capable of controlling the operation of a surface winding machine. It should be understood that certain steps of process 800 can be optional, and in some implementations, process 800 can be implemented using fewer than all steps. It will also be understood that... Figure 8 The order of the steps shown is not intended to be restrictive.

[0089] In step 802, a nonwoven fiber web (e.g., a co-formed nonwoven fiber web) is fed through the winding drum of a surface winder and onto the core. Specifically, the nonwoven fiber web is guided through (e.g., above or below) the winding drum such that one side of the nonwoven fiber web contacts a portion of the outer surface of the winding drum. In some embodiments, the nonwoven fiber web may be fed through the winding drum at the output of the co-formed nonwoven fiber web production line. For example, the surface winder may be positioned at the end of the co-formed nonwoven fiber web production line to wind the resulting co-formed nonwoven fiber web. As described above, the winding drum of the surface winder may be abutted against the core load, for example, the core rotating with the winding drum as the winding drum rotates.

[0090] In step 804, the winding drum is operated to wind the nonwoven fiber web around the core, thereby forming a roll. In some embodiments, the winding drum is operated by providing power to an electric motor that drives the winding drum to rotate the winding drum. In some embodiments, a pulse width modulation (PWM) signal is provided to the electric motor (e.g., by controller 510) to operate the winding drum. In some embodiments, instead of providing power and / or control signals directly to the motor for the winding drum (e.g., motor 216), controller 510 provides a setpoint speed or other control command / signal to the VFD, and the VFD controls the motor and thereby controls the speed of the winding drum. For example, controller 510 may transmit a speed setpoint to the VFD, and then the VFD operates the winding drum motor.

[0091] In step 806, as the nonwoven fiber web is wound onto the core to form a roll, the stretch of the winding cylinder is periodically increased and then decreased. Specifically, the controller 510 may periodically increase the stretch by a first amount and then decrease the stretch by a second amount (e.g., in a stepped or sinusoidal pattern). As described above, this stretch variation consistently alters the tension of the nonwoven fiber web during winding. Generally, the second amount is less than the first amount, causing the average stretch to increase over time; or, it increases as the diameter of the roll of nonwoven fiber web increases. In some embodiments, the periodic increase and subsequent decrease of stretch (e.g., step 806) is repeated until the roll reaches a threshold diameter. (Refer to above) Figure 6 and Figure 7 Details of this periodic increase and subsequent decrease in stretching are provided.

[0092] In some embodiments, the surface winding machine begins an initial stretching operation (e.g., at step 804) until the roll diameter reaches an initial threshold, and after the roll diameter reaches the initial threshold, begins a periodic increase and subsequent decrease in stretching (e.g., at step 806). In some embodiments, for each periodic increase and decrease in stretching—in other words, for each repetition of step 808—the stretching is maintained at an increasing value until the roll diameter increases by a first amount, and / or maintained at a decreasing value until the roll diameter increases by a second amount. For example, for each repetition of step 808, the stretching could be maintained at an increasing value until the roll diameter increases by four inches, and maintained at a decreasing value until the roll diameter increases by two inches. Therefore, during step 806, the controller 510 can be configured to periodically and / or continuously measure the roll diameter (e.g., using a roll thickness sensor 220).

[0093] See now Figure 9 A flowchart of process 900 for variably controlling a surface winding machine based on a step waveform stretching curve, according to some embodiments, is shown. In some embodiments, process 900 is a continuation of steps 804 and / or 806 of process 800, as discussed above. In some embodiments, process 900 is implemented by controller 510, as described above. However, it should be understood that process 900 can be implemented by other means capable of controlling the operation of the surface winding machine. It should be understood that some steps of process 900 may be optional, and in some implementations, process 900 may be implemented using fewer than all steps. It will also be understood that... Figure 9 The order of the steps shown is not intended to be restrictive.

[0094] In step 902, the winding drum (e.g., the winding drum of a surface winding machine) is subjected to an initial stretching operation until the resulting roll of nonwoven fiber web (e.g., a co-formed nonwoven fiber web) reaches a first diameter. Generally, the initial stretching remains constant until the roll of nonwoven fiber web reaches the first diameter. In some embodiments, the controller 510 determines that the roll has reached the first diameter by measuring the diameter of the roll using one or more sensors (e.g., roll thickness sensor 220). In other embodiments, the controller 510 infers the diameter of the roll by tracking the number of rotations of the roll and / or the winding drum, and / or by tracking the amount of time that has elapsed since the winding of the roll began. As discussed above with respect to step 804 of process 800, in some embodiments, the winding drum is operated by providing power to an electric motor that drives the winding drum to rotate the winding drum. In some embodiments, (e.g., by the controller 510) a PWM signal is provided to the electric motor to operate the winding drum. In some implementations, instead of directly supplying power and / or control signals to the motor used for the winding drum (e.g., motor 216), the controller 510 provides a setpoint speed or other control commands / signals to the VFD, and the VFD controls the motor and thereby controls the speed of the winding drum. For example, the controller 510 may transmit a speed setpoint to the VFD, and then the VFD operates the winding drum motor.

[0095] In step 904, the stretch is increased by a first amount and maintained at that increased amount until the roll reaches the second diameter. In other words, the stretch of the winding spool is "gradually increased" to a peak and maintained at that peak until the roll reaches the second diameter. In some embodiments, the "first amount" corresponds to a percentage or amount relative to a previous stretch (e.g., an initial stretch), rather than a specific value. For example, the stretch may be 0.75% greater than a previous stretch. Similarly, the "second diameter" may be relative to the first diameter. For example, the second diameter may be four inches larger than the first diameter. In some embodiments, step 904 includes periodically and / or continuously measuring the diameter of the roll (e.g., using a roll thickness sensor 220) to determine when the roll has increased to the second diameter.

[0096] In step 906, the stretch is reduced by a second amount and held at the reduced amount until the roll reaches the third diameter. In other words, the stretch of the winding roll is "gradually reduced" to a trough and held at the trough until the roll reaches the third diameter. In some embodiments, the "second amount" corresponds to a percentage or amount relative to the previous stretch (e.g., the increased stretch from step 904) rather than a specific value. For example, the stretch may be 0.72% less than the previous stretch. Generally, as discussed herein, the second amount is typically less than / less than the first amount. In other words, each increase in stretch (e.g., step 904) is greater in magnitude than the subsequent decrease in stretch. Similarly, the "third diameter" may be relative to the second diameter. For example, the third diameter may be two inches larger than the first diameter. Similar to step 904, step 906 may also include periodically and / or continuously measuring the diameter of the roll (e.g., using roll thickness sensor 220) to determine when the roll increases to the third diameter.

[0097] It is worth noting that steps 904 and 906 of process 900 can be repeated (e.g., periodically) at least until the roll of the nonwoven fiber web reaches its final diameter. For example, the stretch of the surface winding machine can be increased from a "valley" value to a new peak value and held at the new peak value until the roll reaches a fourth diameter; then, the stretch of the surface winding machine can be decreased from the new peak value to a new "valley" value and held at the new "valley" value until the roll reaches a fifth diameter; and so on. As described above, for each repetition of steps 904 and 906, the stretch can be increased / decreased relative to the previous or "most recent" stretch, such that each increase and decrease in stretch value is greater than the most recently increased or decreased stretch value, respectively.

[0098] Conversion processing of nonwoven fiber webs

[0099] As discussed in detail above, the disclosed systems and methods can help reduce or eliminate the variability in the thickness of the entire roll of nonwoven fiber web, which in turn can reduce or eliminate downstream problems (e.g., when converting the roll into finished products). It should also be understood that rolls of nonwoven fiber web produced using the systems and methods described herein (e.g., first roll 210 and / or second roll 212) can be converted into a variety of articles. The above discussion regarding... Figure 3 , Figure 4A and Figure 4B One such article discussed briefly is a wipe (e.g., a wet wipe). Wipes are typically folded sheets of nonwoven material (e.g., co-formed nonwoven web 204). Wipes are usually produced in the form of a stack of n folded sheets to be packaged and / or stored. Example systems and related methods for producing and stacking sheets of nonwoven web (e.g., for wipes) are described below; however, it should be understood that many other techniques for producing stacks of nonwoven materials can be used.

[0100] See now Figures 10A to 10C Generally speaking, various schematic diagrams of a system 1000 for converting nonwoven materials into sheet laminates according to some embodiments are shown. From Figure 10A Starting from the right side, a roll 1030 of substrate material 1031 is shown. In some embodiments, the roll 1030 of substrate material 1031 may include a device 10 (e.g., such as...). Figure 1 (shown and described) and surface winding machine 200 (e.g., using such as Figures 2 to 9 Rolls of nonwoven material (e.g., first roll 210 and / or second roll 212) formed by the variable winding stretch curve shown and described.

[0101] Generally, roll 1030 may be supported by roll support 1033. Substrate material 1031 is fed from roll 30 through a series of advance rollers (such as idler roller 32 and floating roller 1034). From there, the fiber web of substrate material 1031 travels to slitting assembly 1040. Slitting assembly 1040 may include anvil roller 1042 and slitting blade 1044, which forms weakening lines 1024 (e.g., perforated slitting blade, thus forming perforations 1025) in the sheet as it travels through slitting assembly 1040 along longitudinal direction 1038. As it travels through slitting assembly 1040, the fiber web is formed to join multiple panels 1028 of adjacent panels along multiple weakening lines 1024. Next, the fiber web of substrate material 1031 travels on upper idler roller 1046 and reaches arched roller assembly 1050. The fiber web then travels into folding assembly 1060. The folding assembly 1060 typically includes a series of folding plates 1062 that facilitate controlled necking of the fiber web in the transverse direction 1039, thereby inducing folding in the longitudinal direction 1038.

[0102] In some embodiments, the wetting assembly 1070 may apply a liquid (e.g., detergent or other solution) as the fiber web travels downward through the folding assembly 1060. The wetting assembly 1070 may include a rod 1072 having a port 1074 for applying the liquid or solution to the moving fiber web as the moving fiber web necks into a fan-shaped fold of material. The liquid or solution may be supplied to the rod 1072 at the desired addition rate and in a conventional manner, so that it can be applied to the moving fiber web through the port 1074. This application may include spraying or dripping with the rod 1072, or may include alternative structures (not shown) for techniques such as printing, dipping, immersion rollers, or hollow folding plates with nozzles that spray fluid in a fairly flat horizontal plane as the fiber web moves through the plate. Alternatively, if a dried final product is required, the wetting assembly may be omitted, and the manufacturing equipment and process may remain the same. As the fiber web travels further downward along the folding assembly 1060, it becomes corrugated until it is compressed laterally by the rollers 1076. At this point, the fiber web forms a belt of single-fan-shaped folded sheets, which then travels through the conveying assembly 1080, which includes a traction roller 1082, a support belt 1084, and a support roller 1086, which is an idler roller and a drive roller. The fiber web continues to the adhesive coating assembly 1090. The adhesive coating assembly 1090 can apply adhesive 1092 to the top of the belt, for example, along the edge, via adhesive nozzles 1096. The adhesive can be applied using various techniques known to those skilled in the art.

[0103] An adhesive-coated fiber web—now called a “belt”—travels to a cutter assembly 1001, which includes a rotary cutter 1002 and an anvil roller 1004. The belt is then cut into discrete pieces, called clips 1020, which are then passed to a stacker assembly 1010. This stacker assembly includes a stacker belt 1012 and a stacker roller 1014, which is both an idler roller and a drive roller. In the stacker assembly 1010, the clips 1020 are stacked one on top of the other, and adhesive 1092 on the top sheet of each clip adheres to the bottom sheet of the subsequent clips stacked on top of it. The desired number of clips 1020 are stacked one on top of the other and adhesively joined in this manner. The completed stack is then moved to a packaging assembly (not shown), where the clips can be placed into various types of dispensers (e.g., drums, bags, etc.) and ready for commercial sale and use. Generally, a “stack” as described herein includes at least two clips 1020, each clip including at least two sheets 1022. In some embodiments, the at least two sheets 1022 are separably joined together along a weakening line 1024. Each clip in the clips 1020 can be separably joined to an adjacent clip, for example, by joining the last sheet of one clip to the first sheet of a subsequent clip. In some embodiments, a stack of fan-shaped folded material allows any sheet in one clip to join to any sheet in a subsequent clip, provided that the distribution of sheets from the preceding clip simultaneously distributes at least one sheet from the subsequent clip, so as to continue the continuous distribution of the entire stack 1010 as needed.

[0104] As described herein, when each sheet of a plurality of sheets (e.g., in a sheet stack) engages any adjacent sheet in a dispenser or package, the material sheets can be considered “separably engaged” such that at least a portion of the subsequent sheet is withdrawn through the dispenser or package opening before the preceding and subsequent sheets are completely separated from each other. Such engagement of any adjacent sheets may include a non-overlapping relationship between adjacent sheets in one or more of the following engagement methods: adhesive, friction, cohesion, melt bonding (e.g., ultrasonic welding, heat sealing), mechanical entanglement (e.g., needle punching, vapor sealing, embossing, crimping), self-adhesion, and / or weakening lines (e.g., perforations, brittle areas, scribing, extrusion cutting).

[0105] Specifically, Figure 10B and Figure 10CA portion of the arched roller assembly 1050 and the folding assembly 1060 is shown in more detail. Specifically, mounting rods 1065a and 1065b are shown for mounting and positioning the folding plates as needed. Rods 1066 can also be used to help align the fan-shaped folded material as it leaves the folding plate area and advances into the roll 1076. It should be understood that the number of plates 1062 can be easily varied to achieve the desired folding pattern. Furthermore, other folding techniques and structures can be employed, such as using folding blades, folding pins, or other techniques to mechanically push or guide the sheet into the desired folding pattern.

[0106] exist Figure 10B In this case, for example, plate 1062 can be adjustably fixed to a conventional mounting mechanism, and thus, plate 1062, mounted by rod 1065a, is positioned in front of the fan-folded material (e.g., and this is in such cases as...). Figure 10A (which may be visible in the view), and the plate 1062, mounted by rod 1065b, is positioned behind the fan-folded material (e.g., and this is in such a view). Figure 10A (This may not be visible in the view). Thus, when a sheet of fiber web material is folded from a flat sheet near the arched roller assembly 1050 into a fan-shaped fold configuration, the sheet zigs between adjacent fold plates, the fan-shaped fold configuration starting from the top of the fold plate closest to the arched roller assembly 1050 and descending to the bottom of the fold plate area and the nearest roller 1076. In some embodiments, to reduce tension on the sheet and / or to aid its passage through the fold assembly 1060, the arched roller assembly 1050 may be tilted back to a certain degree (e.g., from about 1 degree to about 10 degrees, or from about 3 degrees to about 7 degrees, or about 5 degrees), tilting backward from the vertical direction seen at 1058a to an angle deviating from the vertical direction seen at 1058b, denoted by angle 1058.

[0107] In some embodiments, the folding plates 1062 are spaced apart from each other by a certain amount in both the longitudinal and transverse directions. As the fan-folded fiber web travels further down along the folding plates 1062 toward the roll 1076, the folding plates 1062 may be spaced closer together in both the longitudinal and transverse directions, thereby fan-folding the flat sheet into a strip structure comprising multiple fan-folded sheets. In some embodiments, the folding plates 1062 may be oriented in a fan-out configuration as shown. In practice, except for the central position, the weakening lines, facets, and fold lines of the fan-folded material are typically skewed relative to all the corresponding theoretical positions shown. Although the folding plates 1062 form fold lines, the material sheet will slide on the folding plates 1062 and converge toward the center of the sheet (e.g., the middle folding plate), and the actual fold lines are typically determined only when the material has passed the folding plate area and is ready to enter the roll 1076. It should be understood that the orientation of all the folding plates 1062 as a group and the orientation of the folding plates relative to each other can depend on many factors. These factors may include, but are not limited to, the properties of the material being folded, the amount of liquid added to the material, the strength of the weakening lines between adjacent panels, the operating speed, the necking of the material, the desired folding pattern of the sheet, or the distance between the roller assembly 1050 and the roll 1076. For example, the tension of the sheet (e.g., a stretch in the range of about 1% to about 10%, or about 3% to about 6%, or about 4%) can be adjusted according to one or more of the factors just discussed to enhance the folding process.

[0108] See now Figure 11A and Figure 11B This illustration shows a perspective view of an example dispensing container 1140 for a stack of sheets (e.g., at least two sheets 1022) produced from a nonwoven material (e.g., a co-formed nonwoven fiber web 204), according to some embodiments. It should be understood that the dispensing container 1140 is merely one example of a container or package for stacks of nonwoven material sheets (e.g., wet wipe stacks), and other types of packaging are contemplated herein. As shown, multiple sheets 1022 can be formed into a stack comprising any suitable number of individual sheets, depending on the desired packaging and end use. For example, a stack of nonwoven material sheets—in this example, a wet wipe—can be configured to comprise at least about five sheets, and ideally about 16 to about 320 individual sheets, and more ideally about 32 to about 160 sheets. The size and shape of the stack of sheets 1022 depend on the size and shape of the package / dispenser, and vice versa. For example, the length of the assembled stack of wet wiping sheet can be about 190 mm, the height can be about 90 mm, and the width can be about 100 mm.

[0109] Each sheet is typically rectangular in shape and defines a pair of opposing sides and a pair of opposing end edges, which may be referred to as front end edges and rear end edges. Each sheet defines an unfolded width and an unfolded length. The sheets may have any suitable unfolded width and length. For example, a sheet of wet wipe may have an unfolded length of about 2.0 cm to about 80.0 cm or about 10.0 cm to about 26.0 cm and an unfolded width of about 2.0 cm to about 80.0 cm or about 10.0 cm to about 45.0 cm. Generally, sheet 1022 may comprise a sheet formed of any suitable nonwoven material, including the co-formed nonwoven material described above. However, for the purposes of this disclosure, sheet 1022 is typically made from a roll of nonwoven material (such as the first roll 210 or the second roll 212 described above), which has been wound using the systems and methods described herein. For wet wipes, each sheet may have a dry basis weight of about 25 g / m² to about 120 g / m² or about 40 g / m² to about 90 g / m².

[0110] In some embodiments—particularly for wet wipes—sheet 1022 may contain a liquid, which can be any solution absorbable into the wipe, thus making them “wet wipes.” Wipes can be wetted at any time before being used by a consumer. During manufacturing, multiple wipes may be wetted before or simultaneously with sealing them in a dispenser or other packaging for the next use by the product user. The liquid contained in the wet wipe may include any suitable components that provide the desired wiping properties. For example, these components may include water, emollients, surfactants, preservatives, chelating agents, pH buffers, fragrances, or combinations thereof. The liquid may also contain lotions, ointments, and / or pharmaceuticals.

[0111] The amount of liquid or solution contained in each wet wipe can vary depending on the type of material used to provide the wet wipe, the type of liquid used, the type of container used to store the stack of wet wipes, and the intended end use of the wet wipe. Generally, each wet wipe may contain about 25% to about 600% by weight or about 200% to about 400% by weight of liquid based on the dry weight of the wipe to improve wiping effectiveness in certain situations. To determine the amount of liquid to add, the weight of the dry wipe just manufactured is first determined. Then, an amount of liquid equal to the weight of the dry wipe just manufactured, or an increase in liquid measured as a percentage addition based on the weight of the dry wipe just manufactured, is added to the wipe to wet it, and this is referred to as the “wet wipe”. In some embodiments, the wet wipe is made of a co-forming material comprising about 30% to about 40% by weight of polymeric microfibers based on the dry weight of the wipe, and the amount of liquid contained in the wet wipe may be about 250% to about 350% by weight or about 330% by weight based on the dry weight of the wet wipe. If the amount of liquid is less than the above range, the wet wipe may be too dry and may not function properly for the intended purpose. If the amount of liquid is greater than the above range, the wet wipe may be oversaturated and become wet, and the liquid may accumulate at the bottom of the container, causing problems with the adhesive 1092 adhering to the surface of the sheet 1022.

[0112] Multiple sheets 1022 (e.g., wet wipes) can be arranged in the package or dispenser in any manner that provides convenient and reliable one-at-a-time dispensing, and for wet wipes, this helps prevent the wipes from becoming too dry. Generally, the storage and dispensing package 1140 includes a non-rigid container 1142 having sides 1150 having a top portion 1152 and a bottom portion 1154, wherein the sides, as well as the top and bottom portions, define a cavity 1156 within the container 1140. The cavity 1156 includes a storage portion 1158 for the wipes. The top portion 1152 may include a resealable mechanism 1100. A non-rigid baffle structure 1110 has a width and is located between the resealable mechanism 1100 and the storage portion 1158, wherein the baffle structure 1110 is positioned between the spaced-apart opposing sides 1150 of the container. The baffle structure 1110 thereby defines the distribution portion 1160 of the cavity 1156 covering the storage portion 1158.

[0113] Generally, the resealable mechanism 1100 can be any type of mechanism that allows the package 1140 to be opened, closed, and reopened multiple times during the package's lifespan, such as a zipper with or without a stopper, a resealable adhesive, a clip, or other structure capable of achieving the desired result here. In use, the resealable mechanism 1100 is opened, and then the dispensing portion 1160 becomes accessible. The user then passes his or her hand, etc., through the orifice 1180 to grasp the first wipe in the wipe stack. If the orifice 1180 is a brittle seal, it must be broken before the user can pass his or her hand through it. Once the user grasps the wipe, it passes through the orifice 1180 and into the dispensing portion 1160 when the user pulls the wipe upward. If the user does not need the wipe immediately, it can be partially dispensed and left in the orifice, where it is held in place by the baffle structure 1110 until later when needed. The partially dispensed wipes will be positioned precisely in orifice 1180, partially in the dispensing section and partially in the storage section, conveniently ready for later dispensing in a pop-up manner. If the user wishes to use the wipes immediately, it can allow the entire wipe to pass through the dispensing section and leave the packaging. Alternatively, if the user pushes a subsequent wipe back into the storage section after popping the previous wipe, it may be necessary to remove the subsequent wipe from the storage section at a later time when the subsequent wipe is needed, similar to the removal of the first wipe from the storage section; this is commonly referred to as insert dispensing. In either case, after the required number of wipes has been removed, the resealable mechanism can be sealed closed, regardless of whether the wipes have been partially dispensed in the dispensing section, as previously discussed. The aforementioned steps can typically be repeated at a later time when another wipe is needed.

[0114] Stack height variability and example test results

[0115] As discussed above, the variability in the thickness of nonwoven webs can cause serious problems when they are downstream processed into finished or "final" products. This variability can be particularly pronounced when multiple sheets are stacked, exacerbating these variations (e.g., in some implementations, each folded sheet in the stack contributes approximately two layers). For example, consider two stacks of 10 layers (e.g., 5 folded sheets) that can form a nonwoven web, where the first stack is produced by a first segment of the roll and the second stack by a second segment of the roll. In this example, the nonwoven web layer in the first segment of the roll may be 0.1 mm thinner than the layer in the second segment of the roll (i.e., having a smaller thickness). This 0.1 mm thickness difference is amplified into a 1 mm height difference between the 10-layer stack.

[0116] In practice, the variability of the stack height in this example can be seen when nonwoven fiber webs are converted into sheets, such as sheet 1022 (e.g., wipes), as described above. For example, when rolls of nonwoven fiber webs are converted into sheets for wet wipes, each stack—having the same number of layers—can vary in height relative to other stacks produced from the same roll. In fairly large rolls of material, these variations in stack height can be clearly visible, for example, when the final product (e.g., a wet wipe stack) is packaged and displayed. In other words, a stack produced from one segment of a roll can be significantly taller (or shorter) than a stack produced from another segment of the same roll.

[0117] To demonstrate the effect of the stretching profile on the variability of the stack height, (i) standard constant stretching techniques and (ii) the variable winding stretching profile described herein are used (e.g., as relative to...). Figures 2 to 9 Multiple sample rolls of nonwoven fiber web are prepared using the methods shown and described herein. The sample rolls are then converted into stacks of folded sheets, referred to herein as “clamps,” and analyzed to determine how the variable stretching technique described herein affects the stack height variation in example converted products (e.g., wipes). Generally, a “clamp” as referred to herein is a stack of eight folded sheets of a nonwoven fiber web; however, it should be understood that in various other embodiments, a “clamp” may include additional or fewer folded sheets. For example, in the above… Figures 10A to 11B In the description, "clamp" refers only to two sheets. Therefore, this disclosure is not intended to be limiting. Furthermore, while an example system and technique for converting rolls of material into folded sheet laminates have been described above, it should be understood that any suitable system and technique for producing folded sheet laminates from rolls of nonwoven fiber webs may be used.

[0118] See now Figure 12 According to some embodiments, graphs illustrating and comparing the results of the above-described tests on the variability of stack height are shown. Specifically, Figure 12 The figure illustrates (i) the recorded height of approximately 2700 clips produced from a first sample roll of a nonwoven fiber web wound at constant tension, denoted as constant tension data point 1202, and (ii) the height of clips produced using the disclosed variable winding tension profile (e.g., Figure 6 The recording height of approximately 2700 clips generated from the second sample roll of the wound nonwoven fiber web (as shown) is represented as variable stretch data point 1204. Figure 12As shown, the constant stretch data point 1202 exhibits a much greater variability than the variable stretch data point 1204 (e.g., the constant stretch data point 1202 shows a downward trend); therefore, the height of the clip produced by the "constant stretch roll" (e.g., represented by the constant stretch data point 1202) tends to vary much more significantly than the height of the clip produced by the "variable stretch roll" (e.g., represented by the variable stretch data point 1204). In fact, Figure 12 The clamp height data indicate that the disclosed systems and methods for changing the winding tension during winding result in a surprisingly smaller change in clamp height throughout the unwinding of the coil.

[0119] Table 1 provides Figure 12 Analysis of the clamp data is shown in Table 1. As shown, the standard deviation of the clamp height decreased from 0.207 (for clamps produced from constant stretch rolls) to 0.137 (for clamps produced from variable stretch rolls). Table 1 also shows that the coefficient of variation decreased from 0.022 (for clamps produced from constant stretch rolls) to 0.015 (for clamps produced from variable stretch rolls). In short, the clamp heights in the clamps produced from the variable stretch rolls are much more consistent than those in the clamps produced from the constant stretch rolls.

[0120] Table 1. – Comparison of clip heights (in mm)

[0121]

[0122] Further research—as shown in Table 2—indicates a decrease in average clip height when unwinding using a standard constant stretch curve. Specifically, using a constant stretch curve, the average clip height of clips formed from the first 10% of the roll (the outermost portion) is 9.429 mm, while the average clip height of clips formed from the last 10% of the roll (the innermost portion) is 8.937 mm. In other words, the average clip height of clips formed from the last 10% of the roll is 5.3% shorter than that of clips formed from the first 10%. This inconsistency will result in significant variations in the stack height of clips produced from the same roll.

[0123] As further shown in Table 2, this problem was solved using a variable stretch curve. Using the variable winding stretch curve described herein, the average clip height of the clips formed from the first 10% of the roll (the outermost portion of the roll) is 9.057 mm, while the average clip height of the clips formed from the last 10% of the roll (the innermost portion of the roll) is 8.914 mm. In other words, the average clip height of the clips formed from the last 10% of the roll is 1.6% shorter than the average clip height of the clips formed from the first 10% of the roll. This improved consistency will reduce significant variations in the stack height of clips produced from the same roll.

[0124] Table 2. – Average clip height of the entire roll (mm)

[0125]

[0126] It was also found that the rate of change of the clip height of sheet laminates processed from rolls wound with constant stretch began to increase at approximately 70% of the unwinding. In other words, the rate of change of clip height increased quantitatively when approximately 30% of the roll remained unwound (for reference, 9.429 mm at 0%–10%; 9.302 mm at 60%–70%; and 8.937 mm at 90%–100%). Conversely, the rate of change of the clip height of sheet laminates processed from rolls wound using the disclosed variable stretching technique remained relatively constant throughout the unwinding process (see, 9.057 mm at 0%–10%; 9.032 mm at 60%–70%; and 8.914 mm at 90%–100%).

[0127] These results are further shown in Figure 13 As shown in Table 3, the rate of change of the average clip height increases at approximately 70% of the unwinding. In fact, even in the last 10% of the roll (e.g., the 10% of the roll closest to the core), the sample variable stretch roll exhibits a lower rate of change than the sample constant stretch roll.

[0128] Table 3. – Rate of change in clip height across the entire roll (mm / % roll)

[0129]

[0130] Configuration of certain implementation methods

[0131] The construction and arrangement of the systems and methods shown in the various embodiments are illustrative only. Although only a few embodiments are described in detail in this disclosure, many modifications are possible (e.g., variations in the size, dimensions, structure, shape and proportions of various elements, parameter values, installation arrangements, use of materials, color, orientation, etc.). For example, the positions of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be changed or varied. Therefore, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. Other substitutions, modifications, alterations, and omissions may be made in the design, operating conditions, and arrangement of the embodiments without departing from the scope of this disclosure.

[0132] This disclosure contemplates methods, systems, and program products on any machine-readable medium for performing various operations. Embodiments of this disclosure can be implemented using existing computer processors, or by a dedicated computer processor for a suitable system, which is incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of this disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available medium accessible by a general-purpose or special-purpose computer or other machine having a processor. In this way, such machine-readable media can include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and is accessible by a general-purpose or special-purpose computer or other machine having a processor.

[0133] When information is transmitted or provided to a machine via a network or another communication connection (hardwired, wireless, or a combination of hardwired and wireless), the machine properly regards that connection as a machine-readable medium. Therefore, any such connection is properly referred to as a machine-readable medium. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, a special-purpose computer, or a special-purpose processor to perform a particular function or group of functions.

[0134] Although the accompanying drawings show a specific order of method steps, the order of steps may differ from the depicted order. Furthermore, two or more steps may be performed simultaneously or partially simultaneously. Such variations will depend on the chosen software and hardware system and the designer's choices. All such variations are within the scope of this disclosure. Similarly, the software implementation may employ standard programming techniques, utilizing rule-based logic and other logic to accomplish various connection steps, processing steps, comparison steps, and decision steps.

[0135] It should be understood that these methods and systems are not limited to specific synthetic methods, specific components, or specific compositions. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0136] As used in the specification and appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly specifies otherwise. A range herein may be expressed as from “about” a particular value and / or to “about” another particular value. When such a range is expressed, another embodiment includes from one particular value and / or to another particular value. Similarly, when a value is expressed as an approximation using the antecedent “about,” it should be understood that the particular value forms another embodiment. It should also be understood that each endpoint of a range is meaningful with respect to another endpoint and is independent of the other endpoint.

[0137] "Optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes instances where the event or situation occurs and instances where it does not occur.

[0138] Throughout the description and claims of this specification, the word “comprising” and its variations, such as “including” and “containing,” means “including, but not limited to,” and is not intended to exclude, for example, other additives, components, integers, or steps. “Exemplary” means “an example of…” and is not intended to convey indications of preferred or ideal embodiments. “Like” is not used in a limiting sense but for interpretive purposes.

[0139] Components that can be used to perform the disclosed methods and systems are disclosed herein. These and other components are disclosed herein, and it should be understood that while specific references to every different individual and collective combination and arrangement may not be explicitly disclosed, when disclosing combinations, subsets, interactions, groups, etc., of these components, every combination and arrangement has been specifically considered and described herein for all methods and systems. This applies to all aspects of this application, including but not limited to the steps in the disclosed methods. Therefore, if various additional steps are available, it should be understood that each of these additional steps can be performed using any particular implementation or combination of implementations of the disclosed methods.

[0140] Example Implementation

[0141] Example 1: A method for manufacturing a nonwoven material, the method comprising: feeding a nonwoven fiber web through a winding drum and onto a core; operating the winding drum to wind the nonwoven fiber web around the core to form a roll of the nonwoven fiber web; and controlling the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first value, and ii) subsequently decreases by a second value, wherein the second value is less than the first value, wherein the periodic increase and subsequent decrease of the tension is repeated until the roll reaches a threshold diameter.

[0142] Example 2: The method according to Example 1 further includes using a sensor to measure the diameter of the roll.

[0143] Example 3: According to the method of Example 2, the control of the winding drum when the nonwoven fiber web is wound onto the core further includes: an initial stretching operation until the diameter of the roll reaches an initial threshold, wherein after the diameter of the roll reaches the second threshold diameter, the periodic increase and subsequent decrease of the stretching begins.

[0144] Example 4: According to the method described in Example 2, wherein for each periodic increase and decrease of the stretch, the stretch is maintained at: i) at an increasing value until the diameter of the roll increases by a first amount, and ii) at a decreasing value until the diameter of the roll increases by a second amount.

[0145] Example 5: The method described in Example 4, wherein the first quantity is greater than the second quantity.

[0146] Example 6: The method described in Example 5, wherein the first quantity is four inches and the second quantity is two inches.

[0147] Example 7: According to the method described in Example 1, the value of each of the first and second values ​​remains constant for each periodic increase and decrease in the stretch.

[0148] Example 8: According to the method described in Example 1, wherein for each periodic increase and decrease of the stretch, the value of one or both of the first value and the second value is different.

[0149] Example 9: The method according to Example 1, wherein the first amount corresponds to a 0.75% increase in the stretch.

[0150] Example 10: The method according to Example 1, wherein the second amount corresponds to a 0.72% reduction in the stretch.

[0151] Example 11: The method according to Example 1, wherein the tension of the nonwoven fiber web during winding varies based on the periodic increase and decrease of the stretching.

[0152] Example 12: According to the method of Example 1, wherein the stretching periodically reduces the second value to form a plurality of release layers in the roll, wherein each of the plurality of release layers is wound with a tension that decreases relative to the tension of the preceding and following layers of the nonwoven fiber web.

[0153] Example 13: The method described in Example 1, wherein the nonwoven fiber web is a co-shaped nonwoven fiber web.

[0154] Example 14: The method according to Example 1 further includes converting the roll of the nonwoven fiber web into a plurality of folded sheet stacks, the plurality of folded sheet stacks including at least two folded sheet stacks generated between the first 10% and the last 10% of the roll of the nonwoven fiber web, wherein the coefficient of variation between the at least two sheet stacks is less than 0.02.

[0155] Example 15: A controller for a machine including a winding drum for winding a nonwoven fiber web onto a core to form a roll of the nonwoven fiber web, the controller including: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the controller to: operate the winding drum to wind the nonwoven fiber web around the core to form the roll; and control the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first amount, and ii) subsequently decreases by a second amount, wherein the second amount is less than the first amount, wherein the periodic increase and subsequent decrease of the tension is repeated until the roll reaches a threshold diameter.

[0156] Example 16: The controller according to Example 15, wherein the instruction further causes the controller to: continuously or periodically measure the diameter of the roll using a sensor.

[0157] Example 17: The controller according to Example 16, wherein the instruction further causes the controller to: perform an initial stretching operation on the winding drum until the diameter of the drum reaches an initial threshold, wherein after the diameter of the drum reaches the second threshold diameter, the periodic increase and subsequent decrease of the stretching begins.

[0158] Example 18: According to the controller described in Example 16, the stretch is maintained for each periodic increase and decrease of the stretch as follows: i) at the increasing value until the diameter of the roll increases by a first amount, and ii) at the decreasing value until the diameter of the roll increases by a second amount.

[0159] Example 19: The controller according to Example 18, wherein the first quantity is greater than the second quantity.

[0160] Example 20: The controller according to Example 19, wherein the third quantity is four inches and the fourth quantity is two inches.

[0161] Example 21: The controller according to Example 15, wherein the first value corresponds to a 0.75% increase in the stretch, and the second value corresponds to a 0.72% decrease in the stretch.

[0162] Example 22: The controller according to Example 15, wherein the tension of the nonwoven fiber web varies based on the periodic increase and decrease of the stretching during winding.

[0163] Example 23: The controller according to Example 15, wherein for each periodic increase and decrease of the stretching speed, the value of each of the first quantity and the second quantity remains constant.

[0164] Example 24: The controller according to Example 15, wherein the stretch periodically reduces the second value to form a plurality of release layers in the roll, wherein each of the plurality of release layers is wound with a tension that decreases relative to the tension of the preceding and following layers of the nonwoven fiber web.

[0165] Example 25: The controller according to Example 15, wherein for each periodic increase and decrease of the stretch, the value of one or both of the first value and the second value is different.

[0166] Example 26: The controller according to Example 15, wherein the nonwoven fiber web is a co-formed nonwoven fiber web.

[0167] Example 27: A system for producing rolls of nonwoven fiber web, the system comprising: a winding drum for winding the nonwoven fiber web onto a core to form the roll; and a controller that operates the winding drum to control the speed of the winding drum by changing the tension as the nonwoven fiber web is wound onto the core, wherein the tension periodically: i) increases by a first amount, and ii) subsequently decreases by a second amount, wherein the second amount is less than the first amount, such that for each periodic increase and decrease of the tension, the tension speed of the winding drum is higher after the decrease of the second amount than before the increase of the first amount.

[0168] Example 28: According to the system described in Example 27, the controller is also configured to use a sensor to measure the diameter of the roll.

[0169] Example 29: The system according to Example 28, wherein controlling the winding drum when the nonwoven fiber web is wound onto the core further includes: operating the winding drum according to an initial stretch until the diameter of the roll reaches an initial threshold, wherein after the diameter of the roll reaches the second threshold diameter, the periodic increase and subsequent decrease of the stretch begins.

[0170] Example 30: The system according to Example 28, wherein for each periodic increase and decrease of the stretch, the stretch is maintained: i) at an increasing value until the diameter of the roll increases by a first amount, and ii) at a decreasing value until the diameter of the roll increases by a second amount.

[0171] Example 31: The system according to Example 30, wherein the first quantity is greater than the second quantity.

[0172] Example 32: The system according to Example 31, wherein the first quantity is four inches and the second quantity is two inches.

[0173] Example 33: The system according to Example 27, wherein for each periodic increase and decrease of the stretch, the value of each of the first quantity and the second quantity remains constant.

[0174] Example 34: The system according to Example 27, wherein for each periodic increase and decrease of the stretch, the value of one or both of the first value and the second value is different.

[0175] Example 35: The system according to Example 27, wherein the first amount corresponds to a 0.75% increase in the stretch.

[0176] Example 36: The system according to Example 27, wherein the second amount corresponds to a 0.72% reduction in the stretch.

[0177] Example 37: The system according to Example 27, wherein the tension of the nonwoven fiber web varies based on the periodic increase and decrease of the stretching during winding.

[0178] Example 38: The system according to Example 27, wherein the stretch periodically reduces the second value to form a plurality of release layers in the roll, wherein each of the plurality of release layers is wound with a tension that decreases relative to the tension of the preceding and following layers of the nonwoven fiber web.

[0179] Example 39: The system according to Example 27, wherein the nonwoven fiber web is a co-shaped nonwoven fiber web.

[0180] Example 40: The system according to Example 27 further includes equipment for converting the roll of the nonwoven fiber web into a plurality of folded sheet stacks, the plurality of folded sheet stacks including at least two folded sheet stacks generated between the first 10% and the last 10% of the roll of the nonwoven fiber web, wherein the coefficient of variation between the at least two sheet stacks is less than 0.02.

[0181] Example 41: A controller for a machine for producing rolls of co-formed nonwoven fiber webs, the machine including a winding drum for winding the co-formed nonwoven fiber web onto a core to form a roll, the controller including: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the controller to: operate the winding drum to wind the co-formed nonwoven fiber web onto the core to form the roll; and control the winding drum to change the tension on the nonwoven fiber web according to a step-wave stretch curve when the co-formed nonwoven fiber web is wound onto the core to form the roll, wherein the step-wave stretch curve includes a series of steps defining multiple peaks in the tension. The series of step rises and falls defines a series of valleys in the stretch, wherein each step rise in the series of step rises is associated with an increase in stretch from a corresponding valley in the series of valleys, and each step fall in the series of step fall is associated with a decrease in stretch from a corresponding peak in the series of peaks, the series of step rises including at least a first step rise from an initial stretch defining a first valley, wherein each step rise in the series of step rises is greater in magnitude than the corresponding step fall in the series of step fall, such that each peak in the series of peaks is associated with a stretch higher than the previous peak in the series of peaks, and each valley in the series of valleys is associated with a stretch higher than the previous valley in the series of valleys.

[0182] Example 42: The controller according to Example 41, wherein the controller is further configured to use a sensor to measure the diameter of the roll.

[0183] Example 43: The controller according to Example 42, wherein the controller is further configured to determine the stretching from the step waveform stretching curve based on the diameter of the roll.

[0184] Example 44: The controller according to Example 42, wherein the controller is configured to increase the stretching according to the first step increase after determining that the roll is above the threshold diameter.

[0185] Example 45: The controller according to Example 44, wherein the controller is configured to maintain the stretch at each of the plurality of peaks until the roll diameter is four inches larger than the roll diameter at the most recent step in the series of step rises.

[0186] Example 46: The controller according to Example 44, wherein the controller is configured to maintain the stretch at each of the plurality of valleys until the roll diameter is two inches larger than the roll diameter at the most recent step drop in the series of step drops.

[0187] Example 47: The controller according to Example 41, wherein each step in the series of step rises is associated with a 0.75% increase in the stretch.

[0188] Example 48: The controller according to Example 41, wherein each step drop in the series of step drops is associated with a 0.72% reduction in the stretch.

[0189] Example 49: A system for producing rolls of co-formed nonwoven fiber webs, the system comprising: a winding drum for winding the co-formed nonwoven fiber web onto a core to form the roll; and a controller for operating the winding drum to wind the co-formed nonwoven fiber web onto the core to form the roll, the controller being configured to control the winding drum to change the tension on the nonwoven fiber web according to a step-wave stretch curve when the co-formed nonwoven fiber web is wound onto the core to form the roll, wherein the step-wave stretch curve includes a series of step rises defining multiple peaks in the tension and a corresponding series of step falls defining multiple valleys in the tension. The series of step rises are associated with an increase in stretch from a corresponding valley in the plurality of valleys, and each step fall in the series of step fall is associated with a decrease in stretch from a corresponding peak in the plurality of peaks. The series of step rises includes at least a first step rise from an initial stretch defining a first valley. Each step rise in the series of step rises is greater in magnitude than the corresponding step fall in the series of step fall, such that each peak in the plurality of peaks is associated with a stretch higher than the previous peak in the plurality of peaks, and each valley in the plurality of valleys is associated with a stretch higher than the previous valley in the plurality of valleys.

[0190] Example 50: The system according to Example 49, wherein the controller is further configured to use a sensor to measure the diameter of the roll.

[0191] Example 51: The system according to Example 50, wherein the controller is further configured to determine the stretching from the step waveform stretching curve based on the diameter of the roll.

[0192] Example 52: The system according to Example 51, wherein the controller is configured to increase the stretching according to the first step increase after determining that the roll is above a threshold diameter.

[0193] Example 53: The system according to Example 52, wherein the controller is configured to maintain the stretch at each of the plurality of peaks until the roll diameter is four inches larger than the roll diameter at the most recent step in the series of step rises.

[0194] Example 54: The system according to Example 52, wherein the controller is configured to maintain the stretch at each of the plurality of valleys until the roll diameter is two inches larger than the roll diameter at the most recent step drop in the series of step drops.

[0195] Example 55: The system according to Example 49, wherein each step in the series of step rises is associated with a 0.75% increase in the stretch.

[0196] Example 56: The system according to Example 49, wherein each step drop in the series of step drops is associated with a 0.72% reduction in the stretch.

[0197] Example 57: A method for producing a roll of co-formed nonwoven fiber web, the method comprising: feeding the co-formed nonwoven fiber web through a winding drum and onto a core; operating the winding drum to wind the co-formed nonwoven fiber web onto the core to form the roll; and controlling the winding drum to change the tension of the nonwoven fiber web according to a step-wave stretch curve while the co-formed nonwoven fiber web is wound onto the core to form the roll, wherein the step-wave stretch curve includes a series of step rises defining multiple peaks in the tension and a corresponding series of step falls defining multiple valleys in the tension, wherein the series Each step rise in the series of step rises is associated with an increase in stretch from the corresponding valley in the plurality of valleys, and each step fall in the series of step falles is associated with a decrease in stretch from the corresponding peak in the plurality of peaks, the series of step rises including at least a first step rise from an initial stretch defining a first valley, wherein each step rise in the series of step rises is greater in magnitude than the corresponding step fall in the series of step falles, such that each peak in the plurality of peaks is associated with a stretch higher than the previous peak in the plurality of peaks, and each valley in the plurality of valleys is associated with a stretch higher than the previous valley in the plurality of valleys.

[0198] Example 58: The method according to Example 57 further includes: measuring the diameter of the roll using a sensor; and determining the stretching from the step waveform stretching curve based on the diameter of the roll.

[0199] Example 59: The method according to Example 58 further includes at least one of the following: maintaining the stretch at each of the plurality of peaks until the roll diameter is four inches larger than the roll diameter at the most recent step rise in the series of step rises; or maintaining the stretch at each of the plurality of valleys until the roll diameter is two inches larger than the roll diameter at the most recent step fall in the series of step falls.

[0200] Example 60: The method according to Example 59, wherein each step up in the series of step ups is associated with a 0.75% increase in the stretch, and wherein each step down in the series of step downs is associated with a 0.72% decrease in the stretch.

[0201] Example 61: A method for winding a co-formed nonwoven fiber web into a roll using a surface winding machine, the surface winding machine including a winding drum configured to wind the co-formed nonwoven fiber web around a core to form the roll, the method comprising: operating the winding drum with an initial stretch value until the diameter of the roll reaches a first threshold; increasing the stretch value of the winding drum by a first amount to a first increased stretch value; operating the winding drum with the first increased stretch value until the diameter of the roll reaches a second threshold; decreasing the stretch value by a second amount to a first decreased stretch value, wherein the second amount is less than the first amount, and wherein the first decreased stretch value is greater than the initial stretch value; operating the winding drum with the first decreased stretch value until the diameter of the roll reaches a third threshold; and increasing the stretch value by a third amount to a second increased stretch value, wherein the second increased stretch value is greater than the increased stretch value.

[0202] Example 62: The method according to Example 61 further includes: operating the winding drum with the second increased stretch value until the diameter of the drum reaches a fourth threshold; and reducing the stretch value by a fourth amount to a second reduced stretch value, wherein the second reduced stretch value is greater than the first reduced stretch value.

[0203] Example 63: The method according to Example 61 further includes using a sensor to measure the diameter of the roll to determine when the diameter of the roll reaches each of a first threshold, a second threshold, and a third threshold.

[0204] Example 64: The method according to Example 61, wherein the first threshold is 14 inches.

[0205] Example 65: The method according to Example 61, wherein the second threshold is 18 inches.

[0206] Example 66: The method according to Example 61, wherein the third threshold is 20 inches.

[0207] Example 67: The method according to Example 61, wherein the first increased stretch value is 0.75% greater than the initial stretch value.

[0208] Example 68: The method according to Example 61, wherein the first reduced stretch value is 0.72% smaller than the first increased stretch value.

[0209] Example 69: The method according to Example 61, wherein the second reduced stretch value is 0.75% greater than the first reduced stretch value.

[0210] Example 70: A controller for a machine for producing rolls of co-formed nonwoven fiber web, the machine including a winding drum for winding the co-formed nonwoven fiber web onto a core to form a roll, the controller including: one or more processors; and a memory storing instructions that, when executed by the one or more processors, cause the controller to: operate the winding drum with an initial stretch value until the diameter of the roll reaches a first threshold; increase the stretch value of the winding drum by a first amount to a first increased stretch value; operate the winding drum with the first increased stretch value until the diameter of the roll reaches a second threshold; decrease the stretch value by a second amount to a first decreased stretch value, wherein the second amount is less than the first amount, and wherein the first decreased stretch value is greater than the initial stretch value; operate the winding drum with the first decreased stretch value until the diameter of the roll reaches a third threshold; and increase the stretch value by a third amount to a second increased stretch value, wherein the second increased stretch value is greater than the increased stretch value.

[0211] Example 71: According to the controller of Example 70, the instructions further cause the controller to: operate the winding drum with the second increased stretch value until the diameter of the drum reaches a fourth threshold; and reduce the stretch value by a fourth amount to a second reduced stretch value, wherein the second reduced stretch value is greater than the first reduced stretch value.

[0212] Example 72: The controller according to Example 70, wherein the instructions further cause the controller to: use a sensor to measure the diameter of the roll to determine when the diameter of the roll reaches each of the first threshold, the second threshold, and the third threshold.

[0213] Example 73: The controller according to Example 70, wherein the first threshold is 14 inches.

[0214] Example 74: The controller according to Example 70, wherein the second threshold is 18 inches.

[0215] Example 75: The controller according to Example 70, wherein the third threshold is 20 inches.

[0216] Example 76: The controller according to Example 70, wherein the first increased stretch value is 0.75% greater than the initial stretch value.

[0217] Example 77: The controller according to Example 70, wherein the first reduced stretch value is 0.72% smaller than the first increased stretch value.

[0218] Example 78: The controller according to Example 70, wherein the second reduced stretch value is 0.75% greater than the first reduced stretch value.

[0219] Example 79: A system for producing rolls of co-formed nonwoven fiber webs, the system comprising: a winding drum for winding the co-formed nonwoven fiber web onto a core to form the roll; and a controller configured to: operate the winding drum with an initial stretch value until the diameter of the roll reaches a first threshold; increase the stretch value of the winding drum by a first amount to a first increased stretch value; operate the winding drum with the first increased stretch value until the diameter of the roll reaches a second threshold; decrease the stretch value by a second amount to a first decreased stretch value, wherein the second amount is less than the first amount, and wherein the first decreased stretch value is greater than the initial stretch value; operate the winding drum with the first decreased stretch value until the diameter of the roll reaches a third threshold; and increase the stretch value by a third amount to a second increased stretch value, wherein the second increased stretch value is greater than the increased stretch value.

[0220] Example 80: The system according to Example 79, wherein the controller is further configured to: operate the winding drum with the second increased stretch value until the diameter of the drum reaches a fourth threshold; and reduce the stretch value by a fourth amount to a second reduced stretch value, wherein the second reduced stretch value is greater than the first reduced stretch value.

[0221] Example 81: The system according to Example 79, wherein the controller is further configured to: use a sensor to measure the diameter of the roll to determine when the diameter of the roll reaches each of the first threshold, the second threshold, and the third threshold.

[0222] Example 82: The system according to Example 79, wherein the first threshold is 14 inches.

[0223] Example 83: The system according to Example 79, wherein the second threshold is 18 inches.

[0224] Example 84: The system according to Example 79, wherein the third threshold is 20 inches.

[0225] Example 85: The system according to Example 79, wherein the first increased stretch value is 0.75% greater than the initial stretch value.

[0226] Example 86: The system according to Example 79, wherein the first reduced stretch value is 0.72% smaller than the first increased stretch value.

[0227] Example 87: The system according to Example 79, wherein the second reduced stretch value is 0.75% greater than the first reduced stretch value.

[0228] Example 88: A plurality of dispensing containers for dispensing stacked sheets from a single nonwoven material roll, the plurality of dispensing containers comprising: a first dispensing container having a first nonwoven sheet stack disposed therein, the first nonwoven sheet stack comprising a sheet formed from the innermost portion of the single nonwoven material roll; and a second dispensing container having a second nonwoven sheet stack disposed therein, the second nonwoven sheet stack comprising a sheet formed from the outermost portion of the single nonwoven material roll; wherein the first nonwoven sheet stack and the second nonwoven sheet stack comprise the same number of sheets, and wherein the clamping height of the first nonwoven sheet stack is within 4% of the clamping height of the second nonwoven sheet stack.

[0229] Example 89: According to the plurality of dispensing containers of Example 88, wherein the clip height of the first nonwoven sheet stack is within 3% of the clip height of the second nonwoven sheet stack.

[0230] Example 90: According to the plurality of dispensing containers of Example 88, wherein the clip height of the first nonwoven sheet stack is within 2% of the clip height of the second nonwoven sheet stack.

[0231] Example 91: According to the plurality of dispensing containers of Example 88, the innermost portion of the single nonwoven material roll is the innermost 10% of the roll in diameter.

[0232] Example 92: According to the plurality of dispensing containers of Example 88, the outermost portion of the single nonwoven material roll is the outermost 10% of the roll in diameter.

[0233] Example 93: A plurality of dispensing containers according to Example 88, wherein the first dispensing container includes a package having an opening for dispensing sheet material from a first nonwoven sheet stack.

[0234] Example 94: A plurality of dispensing containers according to Example 88, wherein the second dispensing container includes a package having an opening for dispensing sheet from a second nonwoven sheet stack.

[0235] According to the plurality of dispensing containers of embodiment 88, the sheets forming the first nonwoven sheet stack and the sheets forming the second nonwoven sheet stack are wetted with liquid, and the first dispensing container and the second dispensing container are configured to retain the liquid within the sheets forming the first nonwoven sheet stack and the second nonwoven sheet stack, respectively.

Claims

1. A method of manufacturing a nonwoven material, the method comprising: feeding a nonwoven web of fibers through a winding drum and onto a core; operating the winding drum to wind the nonwoven web of fibers around the core to form a roll of the nonwoven web of fibers; and controlling a speed of the winding drum by varying a stretch as the nonwoven web of fibers is wound onto the core, wherein the stretch is periodically: i) increased by a first magnitude, and ii) subsequently decreased by a second magnitude, wherein the second magnitude is less than the first magnitude, and wherein the periodic increase and subsequent decrease of the stretch is repeated until the roll reaches a threshold diameter.

2. The method of claim 1, further comprising measuring a diameter of the roll using a sensor.

3. The method of claim 2, wherein varying the stretch comprises: operating at an initial stretch until the diameter of the roll reaches an initial threshold, wherein the periodic increase and subsequent decrease of the stretch is initiated after the diameter of the roll reaches the initial threshold.

4. The method of claim 2, wherein, for each periodic increase and decrease of the stretch, the stretch remains: i) at an increased value until the diameter of the roll increases by a first amount, and ii) at a decreased value until the diameter of the roll increases by a second amount.

5. The method of claim 4, wherein the first amount is greater than the second amount.

6. The method of claim 1, wherein for each periodic increase and decrease of the stretch, the value of each of the first magnitude and the second magnitude remains constant.

7. The method of claim 1, wherein for each periodic increase and decrease of the stretch, the value of one or both of the first magnitude and the second magnitude is different.

8. The method of claim 1, wherein a tension of the nonwoven web of fibers varies during winding based on the periodic increase and decrease of the stretch.

9. The method of claim 8, wherein the stretch periodically decreases by the second magnitude such that a plurality of release layers are formed in the roll, wherein each release layer of the plurality of release layers is wound with a reduced tension relative to a tension of a preceding layer and a subsequent layer of the nonwoven web of fibers.

10. The method of claim 1, wherein the nonwoven web of fibers is a coform nonwoven web of fibers.

11. The method of claim 1, further comprising: converting the roll of the nonwoven web of fibers into a plurality of folded sheet lay ers, the plurality of folded sheet layers comprising at least two folded sheet layers generated between a front 10% and a back 10% of the roll of the nonwoven web of fibers, wherein a height variation coefficient between the at least two sheet layers is less than 0.

02.

12. A controller for a machine, the machine comprising a winding drum that winds a nonwoven web of fibers onto a core to form a roll of the nonwoven web of fibers, the controller comprising: one or more processors; and a memory having instructions stored thereon that, when executed by the one or more processors, cause the controller to: operating the winding drum to wind the nonwoven fibrous web around the core to form the roll of the nonwoven fibrous web; and controlling a speed of the winding drum by varying a stretch as the nonwoven fibrous web is wound onto the core, wherein the stretch is periodically: i) increased by a first amount, and ii) subsequently decreased by a second amount, wherein the second amount is less than the first amount, wherein the periodic increase and subsequent decrease of the stretch is repeated until the roll reaches a threshold diameter.

13. The controller of claim 12, wherein the instructions further cause the controller to: continuously or periodically measure a diameter of the roll using a sensor.

14. The controller of claim 13, wherein the instructions further cause the controller to: operate the winding drum according to an initial stretch until the diameter of the roll reaches an initial threshold, wherein the periodic increase and subsequent decrease of the stretch is initiated after the diameter of the roll reaches the initial threshold.

15. The controller of claim 13, wherein, for each periodic increase and decrease of the stretch, the stretch remains: i) at an increased value until the diameter of the roll increases by a first amount, and ii) at a decreased value until the diameter of the roll increases by a second amount, and wherein the first amount is greater than the second amount.

16. The controller of claim 12, wherein for each periodic increase and decrease of the stretch, the value of each of the first amount and the second amount remains constant.

17. The controller of claim 12, wherein for each periodic increase and decrease of the stretch, the value of one or both of the first amount and the second amount is different.

18. The controller of claim 12, wherein the periodic decrease of the stretch by the second amount causes a plurality of release layers to be formed in the roll, wherein each release layer of the plurality of release layers is wound with a reduced tension relative to a tension of a previous layer and a subsequent layer of the nonwoven fibrous web.

19. A system for producing a roll of a nonwoven fibrous web, the system comprising: a winding drum for winding the nonwoven fibrous web onto a core to form the roll; and a controller that operates the winding drum to wind the nonwoven fibrous web around the core to form the roll, wherein the controller is configured to: control a speed of the winding drum by varying a stretch as the nonwoven fibrous web is wound onto the core, wherein the stretch is periodically: i) increased by a first amount, and ii) subsequently decreased by a second amount, wherein the second amount is less than the first amount, such that for each periodic increase and decrease of the stretch, the stretch of the winding drum is higher after the decrease by the second amount than it was before the increase by the first amount.

20. The system of claim 19, further comprising an apparatus for converting the roll of nonwoven fibrous web into a plurality of folded sheet stacks, the plurality of folded sheet stacks comprising at least two folded sheet stacks created between the innermost 10% and the outermost 10% of the roll of nonwoven fibrous web, wherein a coefficient of height variation between the at least two sheet stacks is less than 0.

02.

21. A plurality of dispensing containers for dispensing stacked sheets from a single roll of nonwoven material, the plurality of dispensing containers comprising: a first dispensing container having a first nonwoven sheet stack disposed therein, the first nonwoven sheet stack comprising sheets formed from an innermost portion of the single roll of nonwoven material; and a second dispensing container having a second nonwoven sheet stack disposed therein, the second nonwoven sheet stack comprising sheets formed from an outermost portion of the single roll of nonwoven material; wherein the first nonwoven sheet stack and the second nonwoven sheet stack comprise the same number of sheets, and wherein a gusset height of the first nonwoven sheet stack is within 4% of a gusset height of the second nonwoven sheet stack.

22. The plurality of dispensing containers of claim 21, wherein the gusset height of the first nonwoven sheet stack is within 3% of the gusset height of the second nonwoven sheet stack.

23. The plurality of dispensing containers of claim 21, wherein the gusset height of the first nonwoven sheet stack is within 2% of the gusset height of the second nonwoven sheet stack.

24. The plurality of dispensing containers of claim 21, wherein the innermost portion of the single roll of nonwoven material is an innermost 10% by diameter of the roll.

25. The plurality of dispensing containers of claim 21, wherein the outermost portion of the single roll of nonwoven material is an outermost 10% by diameter of the roll.

26. The plurality of dispensing containers of claim 21, wherein the first dispensing container comprises a package having an opening for dispensing a sheet from the first nonwoven sheet stack.

27. The plurality of dispensing containers of claim 21, wherein the second dispensing container comprises a package having an opening for dispensing a sheet from the second nonwoven sheet stack.

28. The plurality of dispensing containers of claim 21, wherein the sheets forming the first nonwoven sheet stack and the sheets forming the second nonwoven sheet stack are wetted with a liquid, and wherein the first dispensing container and the second dispensing container are configured to retain the liquid within the sheets forming the first nonwoven sheet stack and the second nonwoven sheet stack, respectively. ​

Images