Soft absorbent co-formed nonwoven web

Abstract

Various embodiments include a fibrous nonwoven web structure having a substantially uniform structure. The nonwoven web includes at least one meltblown fibrous material, at least one secondary fibrous material, and has a TS7 softness value of less than about 7.0. In various embodiments, the fibrous nonwoven web structure further includes a softener.

Description

BACKGROUND OF THE INVENTION

[0001] Nonwoven webs formed as composites of a meltblown thermoplastic fiber material matrix and a minor fiber material, sometimes referred to as coform webs, have been used as absorbent layers in a variety of applications, including absorbent articles, absorbent dry wipes, wet wipes, and mops. However, there is a continuing need to improve the softness and strength characteristics of coform webs. Additionally, there is an ongoing need to improve the manufacturing efficiency of coform webs, which includes reducing material usage and / or waste. SUMMARY OF THE INVENTION

[0002] Some aspects of the present disclosure relate to a fibrous nonwoven structure comprising at least one meltblown fiber material having an average diameter of from about 0.5 to 50 μm; and at least one minor fiber material.

[0003] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the meltblown fiber material to the minor fiber material is between 10 / 90 and 60 / 40.

[0004] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a TS7 value of less than 7.0.

[0005] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure further comprises a softening agent.

[0006] In some aspects, in addition to or in place of any of the foregoing aspects, the softening agent comprises silicone.

[0007] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a TS7 value of less than about 6.0.

[0008] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a TS7 value of less than about 5.0.

[0009] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the softening agent to the minor fiber material is in the range of 10 lb / MT to 80 lb / MT.

[0010] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the softening agent to the minor fiber material is in the range of 20 lb / MT to 60 lb / MT.

[0011] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the softening agent to the minor fiber material is 40 lb / MT.

[0012] In some aspects, in addition to or in place of any of the foregoing aspects, the meltblown fiber material comprises a polymer.

[0013] In some aspects, in addition to or in place of any of the foregoing aspects, the polymer includes polypropylene.

[0014] In some aspects, in addition to or in place of any of the foregoing aspects, the polymer includes polyethylene.

[0015] In some aspects, in addition to or in place of any of the foregoing aspects, the secondary fiber material includes wood pulp.

[0016] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the meltblown fiber material to the secondary fiber material is in the range of 20 / 80 to 60 / 40.

[0017] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the meltblown fiber material to the secondary fiber material is in the range of 25 / 75 to 40 / 60.

[0018] In some aspects, in addition to or in place of any of the foregoing aspects, the weight ratio of the meltblown fiber material to the secondary fiber material is 30 / 70.

[0019] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a flexibility between about 2.5 mm / N and 3.5 mm / N.

[0020] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a flexibility between about 2.7 mm / N and 3.1 mm / N.

[0021] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a transverse tensile strength between about 200 gf and 400 gf.

[0022] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a transverse tensile strength between about 250 gf and 350 gf.

[0023] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a longitudinal tensile strength between about 400 gf and 860 gf.

[0024] In some aspects, in addition to or in place of any of the foregoing aspects, the fibrous nonwoven structure has a longitudinal tensile strength between about 400 gf and 550 gf.

[0025] Additional aspects of the present disclosure will be set forth in part in the following detailed description, the drawings, and the claims, and in part will be derived from the detailed description, or can be learned by practice of the present disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not limit the disclosed disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Exemplary features and embodiments are disclosed in the drawings. However, the present disclosure is not limited to the exact arrangements and means shown.

[0027] Figure 1 is a schematic cross-sectional view of an exemplary nonwoven web in accordance with aspects of the present disclosure.

[0028] Figure 2 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with one embodiment of the present disclosure.

[0029] Figure 3 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0030] Figure 4 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0031] Figure 5 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0032] Figure 6 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0033] Figure 7 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0034] Figure 8 is a schematic view of an apparatus for producing a fibrous nonwoven web structure in accordance with another embodiment of the present disclosure.

[0035] Figure 9 is Figures 2 to 8 a schematic view of certain co-forming features present in the apparatus shown. Detailed Description

[0036] Reference will now be made in detail to various embodiments of the present disclosure, one or more examples of which are shown below. Each example is provided by way of explanation and not limitation. Given the present disclosure, it will be apparent to those skilled in the art that various modifications and variations can be made to the various embodiments described herein without departing from the scope or spirit of the present disclosure.

[0037] As used herein, the term "nonwoven fabric or web" means a web having a structure of interlaid fibers or threads that are not in a regular or identifiable pattern (such as in a knitted fabric). The term also includes foams and films that have been fibrillated, apertured, or otherwise treated to impart fabric-like characteristics. Nonwoven fabrics or nonwoven webs have been formed by a number of processes, such as, for example, meltblowing, spunbonding, hydroentangling, and bonded carded web processes. The basis weight of a nonwoven fabric is typically expressed in ounces per square yard (osy) of material or grams per square meter (gsm), while fiber diameter is typically expressed in μm.

[0038] As used herein, the term "microfiber" means a small diameter fiber having an average diameter of no greater than about 75 μm, such as an average diameter of about 0.5 μm to about 50 μm, or more specifically, an average diameter of about 2 μm to about 40 μm. Another common expression of fiber diameter is denier, which is defined as the number of grams per 9,000 meters of fiber and can be calculated as the fiber diameter in μm squared times the density in g / cc times 0.00707. A lower denier indicates a finer fiber, and a higher denier indicates a coarser or heavier fiber. For example, a polypropylene fiber diameter given as 15 μm can be converted to denier by squaring, multiplying the result by 0.89 g / cc, and multiplying by 0.00707. Thus, the denier number for a 15 μm polypropylene fiber is approximately 1.42 (152 × 0.89 × 0.00707 = 1.415). Outside the United States, the unit of measurement is more commonly "tex", which is defined as the number of grams per kilometer of fiber. Tex can be calculated as denier / 9.

[0039] As used herein, the term "meltblown fiber material" means fibers formed by extruding a molten thermoplastic material through a plurality of generally circular fine die capillaries in the form of molten threads or filaments into a converging high velocity gas (e.g., an air stream), the high velocity gas thinning the filaments of the molten thermoplastic material to reduce its diameter, which can be a microfiber diameter. Thereafter, the meltblown fiber material is carried by the high velocity air stream and deposited on a forming surface of a collecting surface to form a web composed of randomly dispersed meltblown fiber material. Meltblown fiber material is microfibers that may be continuous or discontinuous and typically have an average diameter of less than 10 μm.

[0040] The devices, systems, and methods disclosed herein provide nonwoven web materials that can be used in a variety of applications, including wet wipe products. In various embodiments, the nonwoven web materials include a softening agent that is added during the manufacture of the web (e.g., by co-forming). Adding the softening agent during manufacture improves the softness characteristics of the nonwoven web materials.

[0041] In various embodiments, the nonwoven web material can be used as a substrate in a wet wipe product. The wet wipe product includes an absorbent substrate and a liquid formulation absorbed into the substrate. The liquid formulation can include various chemicals, such as preservatives and fragrances that are diluted (e.g., in water). The wet wipe product can be transformed by wet applying the liquid formulation chemicals to the absorbent substrate. The liquid formulation for the wet wipe product should remain stable, which may limit the formulation chemicals suitable for wet wipes. For example, when the liquid formulation includes a softener, the remaining chemicals in the formulation should be selected such that when mixed with the softener, the resulting liquid formulation remains stable.

[0042] As disclosed herein, applying functional chemicals (e.g., softeners) during the substrate forming process has several advantages, including improved substrate softness, improved substrate holding power, and other improved substrate properties. In certain embodiments, when a softener is added to the substrate during the forming process and the substrate is then used to form a wet wipe product, a wider range of liquid formulations can be added to the substrate. For example, in certain embodiments, the improved softness of the substrate can allow the liquid formulation to be free of softeners, which facilitates the use of a wider range of functional chemicals while maintaining the stability of the liquid formulation (e.g., chemicals that would otherwise compromise the stability of the liquid formulation if included with a softener). Thus, various embodiments of the devices, systems, and methods disclosed herein provide more flexible options for producing wet wipes and other nonwoven web materials with various liquid formulation chemicals, which results in improved consumer-desired properties (e.g., softness, gentleness, and strength) in the wet wipe product. Additionally, as described herein, various embodiments can enable more efficient manufacturing of the nonwoven web material and the wet wipe product made from the nonwoven web material. As discussed herein, when the nonwoven web is used as a substrate in a wet wipe product, applying functional chemicals during the web forming process can provide more flexibility in the liquid formulations used in the wet wipe product (e.g., compared to applying functional chemicals to the formed substrate via wet application during the conversion process).

[0043] Nonwoven web structure

[0044] According to various embodiments, a nonwoven web material that combines a meltblown fiber material and a secondary fiber material (also referred to as a "coform web" or "nonwoven coform web") is disclosed. As discussed in more detail herein, the nonwoven web material can be manufactured using a coform process in which the meltblown fiber material is mixed with the secondary fiber material. In the mixture, a large number of secondary fiber material fibers bond to at least some of the meltblown fiber material fibers to space the meltblown fibers apart. The mixture is collected in the form of a fibrous nonwoven web, and according to various embodiments, the fibrous nonwoven web can be bonded or treated to provide a cohesive nonwoven material. These mixtures are referred to as "coform" materials because they are formed by combining two or more materials into a single structure during a forming step. More details regarding such coform materials and processes are described herein.

[0045] In the coform process, a softening agent is introduced and combined with the mixture of the meltblown fiber material and the secondary fiber material. In various embodiments described herein, the softening agent (e.g., silicone) can be introduced into the coform material at different stages to achieve desired material properties (e.g., softness) and manufacturing efficiency. As described herein, various embodiments of the nonwoven web material have a unique combination of softness and strength properties and can be used to more effectively manufacture consumer products such as wet wipes.

[0046] By the methods and apparatuses described Figures 2 to 9 above, the meltblown fiber material can be combined with the secondary fiber material and the softening agent to produce a coform nonwoven web structure, an exemplary schematic cross-section of which can be seen with respect to Figure 1 the following. Figure 1 The example cross-section of Figure 1 shows a coform nonwoven web structure 100. The nonwoven web 100 is formed by secondary fiber material fibers 101, meltblown fiber material fibers 103, and a softening agent 105. As

[0047] In the illustrated embodiment, the secondary fiber material fibers 101, the meltblown fiber material fibers 103, and the softening agent 105 are substantially uniformly dispersed throughout the nonwoven web 100. Thus, in the illustrated embodiment, the nonwoven web 100 has a substantially uniform structure. In various embodiments, through the mechanical entanglement of the meltblown fiber material fibers 103 with the secondary fiber material fibers 101, the secondary fiber material fibers 101 can be interconnected with each other by the meltblown fiber material fibers 103 and remain captured within the meltblown fiber material fibers. The mechanical entanglement and interconnection of the fibers 101, 103 form a cohesive integrated fiber structure. In various embodiments, the cohesive integrated fiber structure can be formed by the combination of the fibers 101, 103 with the softening agent 105, and there is no adhesive, molecular bond, or hydrogen bond between the two different types of fibers.

[0048] It should be understood that Figure 1 the description in is for illustrative purposes. For example, in some embodiments, the meltblown fiber material fibers 103 and the secondary fiber material fibers 101 may have the same size. Additionally, the meltblown fiber material fibers 103 within the nonwoven web 100 may be arranged as longer and more continuous fibers than Figure 1 shown. Further, there may be intersections or connections between some of the meltblown fiber material fibers 103 and the secondary fiber material fibers 101.

[0049] In various embodiments of the nonwoven web 100, it may be particularly advantageous for the nonwoven web 100 to have a total basis weight between about 20 gsm and about 150 gsm. In more specific embodiments, the nonwoven web 100 may have a total basis weight between about 50 gsm and about 125 gsm, or between about 40 gsm and about 90 gsm, or between about 50 gsm and about 80 gsm. The basis weight of the nonwoven web 100 can also be varied according to the desired end use of the nonwoven web 100. For example, a suitable fibrous nonwoven web structure for wiping the skin may define a basis weight of about 30 to about 80 gsm and desirably about 45 to 70 gsm. The basis weight (in grams per square meter, g / m 2 or gsm) is calculated by dividing the dry weight (in grams) by the area (in square meters).

[0050] In various embodiments, the relative percentages of the meltblown fiber material and the secondary fiber material in the nonwoven web 100 can vary within a wide range depending on the desired characteristics of the nonwoven web 100. For example, the nonwoven web 100 can have from about 20 to 60 weight percent of the meltblown fiber material and from about 40 to 80 weight percent of the secondary fiber material. In certain embodiments, the weight ratio of the meltblown fiber material to the secondary fiber material can be from about 20 / 80 to about 60 / 40. In more specific embodiments, the weight ratio of the meltblown fiber material to the secondary fiber material can be from 25 / 75 to about 40 / 60. In some embodiments, the weight ratio of the meltblown fiber material to the secondary fiber material is 30 / 70.

[0051] In various embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 5 lb / MT to 100 lb / MT. In some embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 10 lb / MT to 80 lb / MT. In some embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 20 lb / MT to 60 lb / MT. In some embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 20 lb / MT to 50 lb / MT. In some embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 20 lb / MT to 40 lb / MT. In some embodiments, the weight ratio of the softening agent to the secondary fiber material is in the range of 30 lb / MT to 40 lb / MT. In some embodiments, the weight ratio of the softening agent to the meltblown fiber material and the secondary fiber material is 40 lb / MT.

[0052] In some embodiments, the nonwoven web 100 has a TS7 value (indicating softness) of less than 7.0. In some embodiments, the nonwoven web has a TS7 value of less than 6.0. In some embodiments, the nonwoven web has a TS7 value of less than 5.0. In some embodiments, the nonwoven web has a TS7 value between about 7.0 and about 3.0. In some embodiments, the nonwoven web has a TS7 value between about 6.0 and about 3.0. In some embodiments, the nonwoven web has a TS7 value between about 6.0 and about 4.0. In some embodiments, the nonwoven web has a TS7 value between about 5.5 and about 4.0.

[0053] In some embodiments, the nonwoven web 100 has a flexibility between about 2.5 mm / N and 3.5 mm / N. In some embodiments, the nonwoven web 100 has a flexibility between about 2.7 mm / N and 3.1 mm / N. In some embodiments, the nonwoven fiber web 100 has a flexibility between 1.0 mm / N and 5 mm / N.

[0054] In some embodiments, the nonwoven web 100 has a machine direction tensile strength (MDT) between about 400 gf and about 860 gf. In some embodiments, the nonwoven web 100 has an MDT strength between about 450 gf and about 700 gf. In some embodiments, the nonwoven web 100 has an MDT strength between about 400 gf and about 550 gf.

[0055] In some embodiments, the nonwoven web 100 has a cross direction tensile strength (CDT) between about 150 gf and about 500 gf. In some embodiments, the nonwoven web 100 has a CDT strength between about 200 gf and about 400 gf. In some embodiments, the nonwoven web 100 has a CDT strength between about 250 gf and about 350 gf.

[0056] Meltblown fiber material

[0057] The meltblown fiber materials suitable for forming the fibers 103 in the nonwoven web 100 include polyolefins (e.g., polyethylene, polypropylene, polybutene, etc.), polyamides, olefin copolymers, and polyesters. In some embodiments, the meltblown fiber materials fibers 103 in the nonwoven web 100 are polypropylene. In some embodiments, the meltblown fiber materials for forming the meltblown fibers 103 are high melt flow rate metallocene-based polypropylene homopolymers (e.g., Metocene MF650X manufactured by LyondellBassell; Achieve TM Advanced PP6945G1) manufactured by ExxonMobil. In various embodiments, the meltblown fiber materials fibers 103 can have an average diameter of about 0.5 to 40 μm.

[0058] In certain embodiments, the nonwoven web 100 can include meltblown fibers 103 that include a first polymer component and a second polymer component (referred to herein as "bicomponent fibers" and also as multicomponent fibers) or meltblown fibers that include homopolymers (referred to herein as "homogeneous fibers" and also as single-component fibers). Although the term "bicomponent fibers" is used herein, it should not be understood to limit such fibers to only two polymer components. Instead, such bicomponent fibers as used herein include at least two polymer components, but may include additional polymer components. The bicomponent meltblown fibers and homogeneous meltblown fibers can be combined in a layered manner together with a minor fiber material to produce a layered coform structure.

[0059] Secondary fiber material

[0060] The secondary fiber material suitable for the nonwoven web 100 or the fibers 101 in forming the nonwoven web may be selected from the group including one or more polyester fibers, polyamide fibers, cellulose-derived fibers (such as rayon fibers and wood pulp fibers), multi-component fibers (such as sheath-core type multi-component fibers), natural fibers (such as silk fibers, wool fibers or cotton fibers), or conductive fibers or a mixture of two or more such secondary fiber materials. Other types of secondary fiber materials may be utilized, such as polyethylene fibers and polypropylene fibers, and mixtures of two or more other types of secondary fiber materials. The secondary fiber material may be microfibers, or the secondary fiber material may be coarse fibers having an average diameter of about 300 μm to about 1,000 μm.

[0061] In at least some embodiments, the secondary fiber material of the fibers 101 forming the nonwoven web 100 may be absorbent fibers. As an example, such absorbent fibers may be fibers formed by various pulping processes, such as kraft pulp, sulfite pulp, thermomechanical pulp, etc. In certain embodiments, wood pulp fibers are suitable for use as the secondary fiber material and are advantageous due to low cost, high absorbency, and maintaining satisfactory tactile properties. The pulp fibers may include softwood fibers having an average fiber length greater than 1 mm and specifically about 2 to 5 mm based on the length-weighted average. Such softwood fibers include, but are not limited to, the following: northern softwood, southern softwood, redwood, red juniper, hemlock, pine (e.g., southern pine), spruce (e.g., black spruce), combinations thereof, and the like. In some embodiments, the secondary fiber material for forming the fibers 101 of the secondary fiber material is a reel of ECF bleached southern pine softwood kraft fluff pulp treated with a debonder and an antistatic agent (medically certified, FDA approved and compliant with BfR) (e.g., available from Georgia-Pacific or International Paper).

[0062] In some embodiments, hardwood fibers such as eucalyptus, maple, birch, poplar, etc. may also be used. In certain cases, eucalyptus fibers may be particularly desirable for increasing the softness of the web. Eucalyptus fibers can also enhance brightness, increase opacity, and alter the pore structure of the web to enhance its capillary action ability. Additionally, if desired, secondary fibers obtained from recycled materials may be used, such as fiber pulp from sources such as newsprint, recycled cardboard, and office waste paper. Additionally, other natural fibers may also be used in the present invention, such as manila hemp, Indian grass, milkweed silk, pineapple leaf, and the like. Additionally, in some cases, synthetic fibers may also be used.

[0063] Other absorbent materials can be used together with pulp fibers, such as superabsorbents in the form of fibers, particles, gels, etc. Generally, a superabsorbent is a water-swellable material that can absorb at least about 20 times its weight, and in some cases at least about 30 times its weight, in an aqueous solution containing 0.9 wt% sodium chloride. Superabsorbents can be formed from natural, synthetic, and modified natural polymers and materials. Examples of synthetic superabsorbent polymers include alkaline earth metal salts and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamide), poly(vinyl ether), copolymers of maleic anhydride with vinyl ether and α-olefins, poly(vinylpyrrolidone), poly(vinylmorpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. In addition, superabsorbents include natural polymers and modified natural polymers, such as starch grafted with hydrolyzed acrylonitrile, starch grafted with acrylic acid, methylcellulose, chitosan, carboxymethylcellulose, hydroxypropylcellulose, and natural gums, such as alginate, xanthan gum, locust bean gum, and the like. Mixtures of natural and fully or partially synthetic superabsorbent polymers can also be used in the present invention.

[0064] Softening agent

[0065] Softening agents suitable for the nonwoven web 100 include, for example, silicones (e.g., silicones diluted in water). In some embodiments, the softening agent includes a nonionic microemulsion of a functional silicone fluid, such as WACKER HC 3502 (34% active silicone by weight) or Shin-Etsu KF-889s, available from Wacker Chemie AG. In some embodiments, the softening agent is transparent or translucent. In some embodiments, the ratio of silicone to water in the softening agent ranges from 10 / 90 to 50 / 50. In some embodiments, the weight ratio of silicone to water in the softening agent is about 34 / 66.

[0066] System and method for manufacturing a nonwoven web structure

[0067] The coformed nonwoven web 100 is generally made by a process in which at least one meltblown die (e.g., two) is arranged near a chute through which absorbent material is added while forming the web. Some examples of such coforming techniques are disclosed in U.S. Patent No. 4,100,324 to Anderson et al., U.S. Patent No. 5,350,624 to Georger et al.; U.S. Patent No. 5,508,102 to Georger et al. and U.S. Patent Application Publication No. 2003 / 0200991 to Keck et al. and U.S. Patent Application Publication No. 2007 / 0049153 to Dunbar et al., all of which are hereby incorporated by reference in their entirety for all purposes.

[0068] In various embodiments, a method of manufacturing a nonwoven web structure is disclosed that allows for the spraying of functional chemicals during the nonwoven web forming process. The applied functional chemicals can include, but are not limited to, one or more softening agents. In various embodiments, a spray system is used to directly apply the functional chemicals during the web forming process to achieve uniform distribution and mixing of the functional chemicals with the fibers of the meltblown fiber material and the fibers of the secondary fiber material. Process air can be used to keep the sprayed functional chemicals well retained within the web during formation and to provide a substantially uniform structure.

[0069] According to various embodiments, a method for manufacturing a nonwoven web generally includes providing a stream of meltblown fiber material, providing a stream of secondary fiber material, providing a stream of softening agent, and combining the stream of meltblown fiber material, the stream of secondary fiber material, and the stream of softening agent to form a composite stream. The composite stream is then deposited onto a forming surface such that the composite stream forms a nonwoven web having a substantially uniform structure.

[0070] As discussed herein, in certain embodiments, the stream of secondary fiber material and the stream of softening agent are combined to form a mixed stream. The (mixed stream of secondary fiber material and softening agent) is then combined with the stream of meltblown fiber material to form a composite stream. In other embodiments, the stream of secondary fiber material and the stream of meltblown fiber material are combined to form a mixed stream, and then the (mixed stream of secondary fiber material and meltblown fiber material) is combined with the stream of softening agent to form a composite stream.

[0071] According to various other embodiments, a method for manufacturing a nonwoven web generally includes providing a mat of secondary fiber material treated with a softening agent and carding the mat to form a mixed stream of secondary fiber material and softening agent. The method further includes providing a stream of meltblown fiber material, and combining the stream of meltblown fiber material with the (mixed stream of secondary fiber material and softening agent) to form a composite stream. The composite stream is then deposited onto a forming surface such that the composite stream forms a nonwoven web having a substantially uniform structure.

[0072] Figure 2FIG. 200 shows an apparatus for forming a fibrous nonwoven structure according to some embodiments. The apparatus 200 includes a conventional evacuation roll 236 configured for pulping fibrillation. The evacuation roll 236 has a plurality of teeth 238 adapted to separate a mat or floc 240 of secondary fibrous material into individual secondary fibrous materials 232 (e.g., secondary fibrous material fibers). The mat or floc 240 of secondary fibrous material fed to the evacuation roll 236 can be a pulp fiber sheet (if a two-component mixture of thermoplastic polymer fibers and secondary pulp fibers is desired), a chopped fiber mat (if a two-component mixture of thermoplastic polymer fibers and secondary chopped fibers is desired), or both a pulp fiber sheet and a chopped fiber mat (if a three-component mixture of thermoplastic polymer fibers, secondary chopped fibers, and secondary pulp fibers is desired). In aspects where, for example, an absorbent material is desired, the secondary fibrous material 232 is absorbent fibers. The secondary fibrous material 232 is generally selected from the materials disclosed herein for forming the fibers 101 as Figure 1 shown.

[0073] A sheet or mat 240 of secondary fibrous material is fed to the evacuation roll 236 by a roll device 242. After the teeth 238 of the evacuation roll 236 have separated the sheet or mat 240 of secondary fibrous material into individual secondary fibrous materials 232, the individual secondary fibrous materials 232 (e.g., secondary fibrous material fibers 101) are directed through a nozzle 244 to form a stream 234 of secondary fibrous material.

[0074] A housing 246 surrounds the evacuation roll 236 and provides a passage or gap between the housing 246 and the surface of the teeth 238 of the evacuation roll 236. Dilution gas, such as air, is supplied by a dilution air blower 272 through a gas conduit 250 to the passage or gap between the surface of the evacuation roll 236 and the housing 246. The gas is supplied in an amount sufficient to serve as a medium for transporting the secondary fibrous material 232 through the nozzle 244, thereby forming a secondary fibrous material stream 234.

[0075] In some embodiments, a dual-ring manifold serves as the dilution air blower 272, providing a uniform air distribution for delivering air into the gas conduit 250. The dilution air provided by the dual-ring manifold delivers the pulp fibers uniformly to a forming zone 230 above a forming surface 258 (such as a belt or wire), which will be discussed further herein.

[0076] A separate stripping air blower 274 is used to provide a secondary stripping air stream entering the system at the junction 252 to assist in removing the secondary fibrous material 232 from the teeth 238 of the evacuation roll 236. The use of a separate dilution air blower 272 and stripping air blower 274 allows the operator to balance the stripping air stream, allowing for optimal fiber release from the teeth 238 and an increase in the flow rate of the secondary fibrous material stream 234.

[0077] In various embodiments, the secondary fiber material stream 234 is conveyed through the nozzle 244 at approximately the same speed as the individual secondary fiber material 232 exits the teeth 238 of the evacuation roll 236. In other words, when the secondary fiber material 232 exits the teeth 238 of the evacuation roll 236 and enters the nozzle 244, it generally maintains its velocity in magnitude and direction at the point where it exits the teeth 238 of the evacuation roll 236. Such an apparatus is discussed in more detail in U.S. Patent No. 4,100,324 to Anderson et al.

[0078] As Figure 2 shown, the softener manifold 290 is disposed below the nozzle 244, downstream of the introduction portion of the stream 234 of the secondary fiber material 232 and upstream of the introduction portions of the streams 226, 228 of the meltblown fiber material 220. The softener manifold 290 includes a body (e.g., a tubular body) defining one or more openings 292. Softener is introduced into the body of the softener manifold 290 under pressure such that the softener flows through one or more openings 292 and out of the softener manifold 290 to form one or more softener streams 294. The softener is typically selected from the materials disclosed herein for forming the softener 105 (as Figure 1 shown).

[0079] In certain embodiments, each of the one or more openings 292 of the softener manifold has a diameter between about 0.01 inches and 0.05 inches. In one embodiment, each of the one or more openings 292 of the softener manifold has a diameter of 0.02 inches. In various embodiments, the one or more openings 292 of the softener manifold include a plurality of openings 292. In certain embodiments, the plurality of openings 292 are aligned in rows along the length of the softener manifold 290 and are evenly spaced from each other. In various embodiments, the openings 292 of the softener manifold are spaced 0.5 inches to 2.0 inches from each other. In one embodiment, the openings 292 of the softener manifold are spaced one inch from each other (e.g., such that the softener manifold 290 includes one opening 292 per inch along its length). In another embodiment, the openings 292 of the softener manifold are spaced two inches from each other (e.g., such that the softener manifold 290 includes one opening 292 per two inches along its length). In one embodiment, the softener manifold includes twelve openings 292, each having a diameter of 0.02 inches, and each opening is spaced one inch from the others in a linear row.

[0080] In other embodiments, the openings 292 of the softener manifold may each include a spray nozzle fixed to the manifold 290. For example, in one embodiment, the openings 292 of the softener manifold include four flat spray nozzles. Each spray nozzle has an orifice diameter of, for example, 0.02 inches (e.g., McMaster-Carr drip-proof flat spray nozzle, part number 4846T112). The four spray nozzles 292 are evenly spaced from each other (e.g., spaced 3 inches from each other along the length of the softener manifold 290).

[0081] As Figure 2 shown, one or more openings 292 of the softener manifold 290 are oriented such that one or more softener streams 294 flowing out of the one or more openings 292 merge with the secondary fiber material stream 234 exiting the nozzle 244 at an angle. In this way, the merging of the one or more softener streams 294 and the secondary fiber material stream 234 forms a mixed stream 235 of secondary fiber material and softener.

[0082] As Figure 2 further depicted, in the apparatus 200, the softener manifold 290 is positioned on a side of the secondary fiber material stream 234 adjacent to the second meltblown die 218 and opposite the first meltblown die 216 (the meltblown dies 216, 218 are discussed in more detail herein). In this way, the softener stream 294 discharged from the softener manifold 290 merges with the secondary fiber material stream 234 on a side of the secondary fiber material stream 234 that is longitudinally downstream relative to the forming surface 258. As Figure 2 shown, the softener stream 294 discharged from the softener manifold 290 merges with the secondary fiber material stream 234 on the downstream side of the secondary fiber material stream 234, which is the side adjacent to the second meltblown die 218 and the nonwoven web 254 on the forming surface 258.

[0083] In various embodiments, the angle of the one or more softener streams 294 relative to the secondary fiber material stream 234 is selected to facilitate the merging of the streams. For example, in Figure 2 the illustrated embodiment, the angle of the one or more softener streams 294 relative to the secondary fiber material stream 234 is about 45 degrees.

[0084] In various embodiments, the speed and flow rate of one or more softener streams 294, together with the angle of one or more softener streams 294 relative to the secondary fiber material stream 234, are configured to cause the softener to fully merge with the secondary fiber material 232 such that the softener is substantially uniformly dispersed throughout the nonwoven web material. In certain embodiments, the flow rate of one or more softener streams 294 (collectively passing through the softener manifold 230) is between about 250 mL / min and 1000 mL / min. In certain embodiments, the flow rate of one or more softener streams 294 (collectively passing through the softener manifold 230) is between about 400 mL / min and 600 mL / min. In one embodiment, the flow rate of one or more softener streams 294 (collectively passing through the softener manifold 230) is 425 mL / min. In another embodiment, the flow rate of one or more softener streams 294 (collectively passing through the softener manifold 230) is 600 mL / min.

[0085] Apparatus 200 further includes a first meltblown die 216 and a second meltblown die 218 which are oriented such that they face each other. Each meltblown die 216, 218 is associated with a pellet hopper 212, 212' and an extruder 214, 214'. Pellets or chips etc. (not shown) of a thermoplastic polymer are introduced into each pellet hopper 212, 212' for feeding into the meltblown dies 216, 218. Extruder 214 has an extrusion screw (not shown) which is driven by a conventional drive motor (not shown). As the polymer advances through the extruder 214, the polymer is gradually heated to a molten state as the drive motor rotates the extrusion screw. Heating the thermoplastic polymer to a molten state can be accomplished in multiple discontinuous steps, with its temperature gradually increasing as it passes through discontinuous heating zones of the extruder 214 towards the two meltblown dies 216 and 218 respectively. The meltblown dies 216, 218 can be another heating zone where the temperature of the thermoplastic resin is maintained at an elevated level for extrusion.

[0086] In Figure 2In an exemplary implantation, each meltblown die 216, 218 is configured such that two converging gas streams of each die converge to form a single gas stream that entrains and attenuates the meltblown fiber material 220 (e.g., a strand of thermoplastic polymer) as the meltblown fiber material 220 exits the orifices or apertures 224 in the respective meltblown dies 216, 218. The meltblown fiber material 220 is attenuated into fibers or, depending on the degree of attenuation, formed into microfibers having a small diameter, which is typically smaller than the diameter of the orifice 224. Accordingly, each of the meltblown dies 216 and 218 discharges a meltblown fiber material stream 226, 228 that consists of a gas containing the entrained and attenuated meltblown fiber material 220 (e.g., thermoplastic polymer fibers). The first meltblown fiber material stream 226 and the second meltblown fiber material stream 228 containing the meltblown fiber material 220 are aligned to converge at the forming zone 230.

[0087] A mixed stream 235 of the secondary fiber material 232 and the softening agent merges with the two meltblown fiber material streams 226, 228 of the meltblown fiber material 220 (e.g., thermoplastic polymer fibers or microfibers) at the forming zone 230 to form a composite stream 256. In various embodiments, the fibers (e.g., microfibers) of the meltblown fiber material streams 226, 228 are in a soft as-spun state at an elevated temperature when turbulently mixed with the secondary fiber material 232 and the softening agent in the air within the forming zone 230. Merging the mixed stream 235 into the two meltblown fiber material streams 226, 228 is designed to create a distribution of the secondary fiber material 232 and the softening agent within the combined meltblown fiber material streams 226, 228 of the meltblown fiber material 220. As Figure 2 shown, this can be achieved by merging the mixed stream 235 (containing the secondary fiber material 232 and the softening agent) between the two opposing meltblown fiber material streams 226, 228 such that all three gas streams converge in a controlled manner. Regarding Figure 9 the orientation of the meltblown fiber material streams 226, 228 relative to the mixed stream 235 is further discussed.

[0088] Figure 9 illustrates the orientation of the meltblown fiber material streams 226, 228 relative to the mixed stream 235 and highlights process variables that can affect the type and characteristics of the nonwoven web 254. Also shown are various forming distances that affect the type of the fibrous nonwoven web structure 254.

[0089] In various embodiments, meltblown fiber material streams 226, 228 that include a meltblown fiber material 200 (e.g., a thermoplastic polymer fiber) are aligned to converge at a forming zone 230 (also referred to as an impact zone). Generally, the meltblown dies 216, 218 are arranged at an angle relative to a forming surface 258, as described in U.S. Pat. Nos. 5,508,102 and 5,350,624 to Georger et al.

[0090] The use of meltblown dies 216, 218, as described in various embodiments herein, allows for improved forming and softness characteristics. The meltblown dies 216, 218 are mounted such that each can be set at an angle θ. As Figure 9 shown, the angle θ is measured from a plane “A” that is tangent to the meltblown dies 216, 218 and generally parallel to the forming surface 258 (e.g., an annular belt or line). Generally, each die 216, 218 is set and mounted at an angle θ such that the meltblown fiber material streams 226, 228 produced from the dies intersect the forming zone 230. In some embodiments, the angle θ can be in the range of about 30 degrees to about 75 degrees. In certain embodiments, the angle θ can be in the range of about 35 degrees to about 60 degrees. In other embodiments, the angle θ can be in the range of about 40 degrees to about 55 degrees.

[0091] As Figure 9 shown, the meltblown dies 216, 218 are spaced a distance α. Generally, the distance α can range up to about 41 cm (16 inches). In some embodiments, the distance α can be in the range of about 13 cm (5 inches) to about 25 cm (10 inches). In other embodiments, the distance α can be in the range of about 15 cm (6 inches) to about 21 cm (8 inches). As can be appreciated from Figure 9 it, the distance α between the meltblown die heads 216, 218 and the angle θ of each meltblown die head 216, 218 determine the location of the forming zone 230.

[0092] The distance (i.e., distance X) from the forming zone 230 to the tip of each meltblown die 216, 218 should generally be set to minimize the dispersion of each meltblown fiber material stream 226, 228. For example, in various embodiments, the distance X can range up to about 41 cm (16 inches). In certain embodiments, this distance should be greater than 6 cm (2.5 inches). For example, for a distance X in the range of about 6 cm (2.5 inches) to 16 cm (6 inches), the distance from the tip of each meltblown die 216, 218 to the forming zone 230 can be determined from the spacing α between the die tips and the die angle θ using the following formula:

[0093] X = α / (2 cos θ)

[0094] Generally, the dispersion of the composite stream 256 can be minimized by selecting an appropriate vertical forming distance (i.e., distance β) before the composite stream 256 contacts the forming surface 258. β is the distance from the tip of the meltblown dies 216, 218 (e.g., at the orifice 224 of the die) to the forming surface 258. In various embodiments, a shorter vertical forming distance is generally desired to minimize dispersion. This is balanced by the need for the extruded fibers to solidify from their viscous semi-molten state before contacting the forming surface 258. For example, in various embodiments, the vertical forming distance β can range from about 7 cm (3 inches) to about 38 cm (15 inches) from the tip of the meltblown die. Desirably, in some embodiments, this vertical distance β can be from about 10 cm (4 inches) to about 28 cm (11 inches) from the tip of the meltblown die.

[0095] An important component of the vertical forming distance β is the distance (i.e., distance Y) between the forming zone 230 and the forming surface 258. In various embodiments, the forming zone 230 is positioned such that the composite stream 256 travels only the minimum distance (Y) to reach the forming surface 258 to minimize the dispersion of entrained secondary fiber material fibers and meltblown fiber material fibers. For example, in various embodiments, the distance (Y) from the forming zone to the forming surface can be up to about 31 cm (12 inches). Desirably, in some embodiments, the distance (Y) from the forming zone 230 to the forming surface 258 can range from about 5 cm (3 inches) to about 18 cm (7 inches). The distance from the forming zone 230 to the forming surface 258 can be determined from the vertical forming distance β, the spacing (α) between the die tips, and the die angle (θ) using the following formula:

[0096] Y = β - ((α / 2) * cos θ)

[0097] As discussed with respect to Figure 2 the secondary fiber material stream 234 exits the nozzle 244 before merging with the softener stream 294 to form the mixed stream 235. Generally, the nozzle 244 is positioned such that its vertical axis is substantially perpendicular to the forming surface 258. Thus, in various embodiments, both the secondary fiber material stream 234 and the mixed stream 235 are oriented in a direction substantially perpendicular to the forming surface 258.

[0098] In some embodiments, it may be desirable to cool the secondary fiber material stream 234. For example, cooling the secondary fiber material stream 234 can accelerate the quenching of the molten or viscous meltblown fiber material and provide a shorter distance between the meltblown die tip and the forming surface 258, which can be used to minimize fiber dispersion. In some embodiments, the temperature of the secondary fiber material stream 234 can be cooled to about 65 to about 85 degrees Fahrenheit.

[0099] By balancing the meltblown fiber material flows 226, 228 and the mixed flows 235, the desired die angles θ of the meltblown dies 216, 218, the vertical forming distance (β), the distance (α) between the meltblown die tips, the distance (X) between the forming zone 230 and the meltblown die tips, and the distance (Y) between the forming zone 230 and the forming surface 258, a controlled integration of the secondary fiber material 232 and the softening agent can be provided within the meltblown fiber material flows 226, 228.

[0100] Return reference Figure 2 , in order to convert the composite flow 256 (comprising the meltblown fiber material 220, the secondary fiber material 232 and the softening agent) into a nonwoven structure 254 consisting of a cohesive mixture of the meltblown fiber material 220, the secondary fiber material 232 and the softening agent, a collection device is located in the path of the composite flow 256. The collection device includes a forming surface 258 on which the composite flow 256 is disposed. In Figure 2 the illustrated embodiment, the forming surface 258 is an endless belt conventionally driven by a roller 260 and rotates as shown by the direction arrow 262. Other collection devices are well known to those skilled in the art and can be used in place of the endless belt. For example, in other embodiments, a porous drum device can be used.

[0101] The composite flow 256 (of the meltblown fiber material 220, the secondary fiber material 232 and the softening agent) is collected on the forming surface 258 as a cohesive mixture of fibers to form a nonwoven web 254.

[0102] The deposition of the fibers in the composite flow 256 is assisted by an offline vacuum supplied by a negative pressure unit or an offline exhaust system 280. Different from conventional machines, the illustrated offline exhaust system has an increased number of zones, providing three zones in the longitudinal direction. For example, the first zone 282 is located longitudinally upstream of the forming zone 230, the secondary zone 284 is located directly below the pump nozzles and the forming zone 230, and the third zone 286 is located longitudinally downstream of the forming zone 230. In various embodiments, the second zone 284 has the highest air flow, the first zone 282 has the smallest amount of air flow, and the third zone 286 has an air flow higher than that of the first zone 282 but lower than that of the second zone 284. In other embodiments, if found to be optimal, the zones 284, 282, 286 can also supply the same amount of air flow. The zoned offline exhaust system 280 provides increased air flow where needed and better controls the forming zone air management, resulting in improved forming and uniformity.

[0103] The fibrous nonwoven web structure 254 is cohesive and can be removed from the forming surface 258 as a self - supporting nonwoven material. In various embodiments, the nonwoven web 254 has sufficient strength and integrity to be used without any post - processing (such as pattern bonding, etc.). In certain embodiments, a pair of nip rolls or pattern bonding rolls can be used to bond portions of the material.

[0104] According to the above - described apparatus 200 and related processes, through the mechanical entanglement of the thermoplastic polymer fibers with the secondary fiber material 232, the secondary fiber material is interconnected by the melt - blown fiber material 220 and remains trapped within the melt - blown fiber material. The individual mechanical entanglement and interconnection of the polymer fibers and the secondary fiber material are capable of forming a cohesive integrated fiber structure (e.g., the co - formed nonwoven web structure 254). The cohesive integrated fiber structure can be formed by the polymer fibers and the secondary fiber material without any adhesives or molecular or hydrogen bonds between the two different types of fibers. Additionally, as a result of the process implemented on the apparatus 200, the softening agent is substantially uniformly dispersed in the co - formed nonwoven web structure 254, thereby enhancing various properties (e.g., softness) of the nonwoven web 254.

[0105] Figure 3 Another apparatus 300 for forming a fibrous nonwoven structure 254 is shown according to some embodiments. Figure 3 The apparatus 300 shown is similar to Figure 2 the apparatus 200 shown, except for the position of the softening agent manifold 290. In Figure 3 the same or similar reference numerals as those used for the apparatus 200 in Figure 2 are used to denote the same or similar components of the apparatus 300.

[0106] As in the Figure 2 apparatus 200, Figure 3 the apparatus 300 includes a softening agent manifold 290 having one or more openings 292 that are oriented such that one or more softening agent streams 294 flowing out of the one or more openings 292 merge with the secondary fiber material stream 234 leaving the nozzle 244 at an angle. In this way, the merging of the one or more softening agent streams 294 and the secondary fiber material stream 234 forms a mixed stream 235 of the secondary fiber material 232 and the softening agent. However, as Figure 3 shown, in the apparatus 300, the softening agent manifold 290 is located on the opposite side of the secondary fiber material stream 234 (compared to that in the apparatus 200 in Figure 2compared to the softener manifold 290). In other words, in apparatus 300, the softener manifold 290 is positioned adjacent to the first meltblown die 216 (opposite the second meltblown die 218) and adjacent to the upstream portion of the forming surface 258 (the portion on which no nonwoven material is deposited). In this way, the softener stream 294 discharged from the softener manifold 290 merges with the secondary fiber material stream 234 on a side of the secondary fiber material stream 234 that is longitudinally upstream with respect to the forming surface 258.

[0107] Figure 4 Another apparatus 400 for forming a fibrous nonwoven structure 254 is shown in accordance with some embodiments. Figure 4 The illustrated apparatus 400 is similar to Figure 2 the illustrated apparatus 200, except for the position of the softener manifold 290. In Figure 4 the same or similar reference numerals as those used for the Figure 2 apparatus 200 (and Figure 3 the apparatus 300) are used to denote the same or similar features of the apparatus 400.

[0108] As in the Figure 2 apparatus 200, Figure 4 the apparatus 400 includes a softener manifold 290 having one or more openings 292 that discharge one or more softener streams 294. However, in the apparatus 400, the softener manifold 290 is positioned below the second meltblown die 218. In other words, in the apparatus 400, the softener manifold 290 is positioned at a height above the forming surface 258 that is less than the vertical forming distance (β) of the meltblown die (as Figure 9 shown).

[0109] As Figure 4 shown, the secondary fiber material stream 234 and the meltblown fiber material streams 226, 228 merge in the forming zone 230 to form a mixed stream 235 (composed of secondary fiber material 232 and meltblown fiber material 220). The softener manifold 290 of the apparatus 400 is oriented such that the softener stream 294 merges with the mixed stream 235 below the forming zone 230. Thus, in the apparatus 400, the softener stream 294 then merges with the mixed stream 235 to form a composite stream 256 (composed of secondary fiber material 232, meltblown fiber material 220, and softener). The composite stream 256 is then deposited onto the forming surface 258 of the collection device to form the nonwoven web 254 (e.g., in the manner described with respect to Figure 2 the apparatus 200).

[0110] Additionally, as in apparatus 200, the softener manifold 290 in apparatus 400 is positioned adjacent to the second meltblown die 218 and opposite the first meltblown die 216. Thus, in apparatus 400, the softener stream 294 discharged from the softener manifold 290 merges with the mixed stream 235 on a side of the mixed stream 235 that is longitudinally downstream relative to the forming surface 258 (i.e., the side of the mixed stream 235 adjacent to the second meltblown die 218).

[0111] Figure 5 Another apparatus 500 for forming a fibrous nonwoven structure 254 is shown in accordance with some embodiments. Figure 5 The illustrated apparatus 500 is similar to Figure 4 the illustrated apparatus 400, except for the position of the softener manifold 290. In Figure 5 the same or similar reference numerals as used for the apparatus 400 in Figure 4 and the apparatus 200, 300 in Figure 2 and Figure 3 respectively are used to denote the same or similar features of the apparatus 500.

[0112] As in the apparatus 400 of Figure 4 the apparatus 500 of Figure 5 includes a softener manifold 290 having one or more openings 292 that are oriented such that one or more softener streams 294 flowing out of the one or more openings 292 merge with the mixed stream 235 (including the minor fiber material 232 and the meltblown fiber material 220) at an angle. However, in apparatus 500, the softener manifold 290 is located on the opposite side of the mixed stream 235 (compared to the softener manifold 290 of Figure 4 the apparatus 400). In other words, in apparatus 500, the softener manifold 290 is positioned adjacent to the first meltblown die 216 and opposite the second meltblown die 218. In this way, the softener stream 294 discharged from the softener manifold 290 merges with the mixed stream 235 on a side of the mixed stream 235 that is longitudinally upstream relative to the forming surface 258 (i.e., the side of the mixed stream 235 adjacent to the first meltblown die 216).

[0113] Figure 6 Another apparatus 600 for forming a fibrous nonwoven structure 254 is shown in accordance with some embodiments. Figure 6 The illustrated apparatus 600 is similar to Figure 2 the illustrated apparatus 200, except for the position of the softener manifold 290. In Figure 6 the same or similar reference numerals as used for the apparatus 200 in Figure 2 and Figures 3 to 5Like reference numerals are used to denote like features of apparatus 600 that are the same as or similar to those of apparatus 300-500).

[0114] As in Figure 2 apparatus 200, Figure 6 apparatus 600 includes a softener manifold 290 having one or more openings 292 that discharge one or more softener streams 294. However, in apparatus 600, the softener manifold 290 is positioned adjacent to the mat 240 of secondary fibrous material (before the mat 240 enters the evacuation roll 236). The softener manifold 290 of apparatus 600 is oriented such that the softener streams 294 combine with the mat 240 of secondary fibrous material. Once the mat 240 of secondary fibrous material has been treated with softener, the treated mat 240 passes through the evacuation roll 236. The plurality of teeth 238 of the evacuation roll 236 separate the treated mat 240 of secondary fibrous material into individual treated secondary fibrous materials 232, which are themselves a mixed stream 235 (comprising secondary fibrous material and softener). The mixed stream 235 (of secondary fibrous material and softener) flows through the nozzle 244 and combines with the meltblown fibrous material 220 in the forming zone 230 to form a composite stream 256 (e.g., in a manner as described with respect to Figure 2 apparatus 200 shown). The composite stream 256 is then deposited onto the forming surface 258 of the collection device to form the nonwoven web 254 (e.g., in a manner as described with respect to Figure 2 apparatus 200).

[0115] Although Figure 6 apparatus 600 shown includes a softener manifold 290 that treats the mat 240 of secondary fibrous material 232 just before it enters the evacuation roll 236, in other embodiments, the mat 240 of secondary fibrous material is treated with softener at a location remote from apparatus 600. In such embodiments, apparatus 600 may not include the softener manifold 290, and the treated mat 240 of secondary fibrous material is fed into the evacuation roll 236 (e.g., in the same manner as shown and described with respect to Figure 6 ). In some embodiments, the mat 240 of secondary fibrous material treated with softener may be stored until it is used to form the nonwoven web 254. In some embodiments, softener may be added during the process of forming the mat 240 and completely dispersed in the secondary fibrous material (e.g., such that a mat 240 treated with softener supplied from a remote location can then be used in apparatus 600 without the need for a softener manifold 290).

[0116] In some embodiments, it is desirable to feed at least one additional mat of the secondary fiber material together with mat 240 of the secondary fiber material into the evacuation roll 236. In such embodiments, the mats of the secondary fiber material enter the evacuation roll in a layered stack and simultaneously. This can be advantageous in embodiments such as those discussed above, where a softening agent is included in mat 240 of the secondary fiber material. In some cases, using at least one additional untreated mat of the secondary fiber material (e.g., without the addition of a softening agent) between the evacuation roll 236 and the processed mat of the secondary fiber material can reduce the likelihood of mat 240 adhering to the teeth 238 of the evacuation roll 236. In such embodiments, the processed mat of the secondary fiber material (e.g., treated with a softening agent) is disposed on the untreated mat of the secondary fiber material (e.g., where the untreated mat is not treated with a softening agent). Then, the processed mat of the secondary fiber material and the untreated mat of the secondary fiber material are fed into the evacuation roll 236. Since the processed mat of the secondary fiber material that has been treated with a softening agent is covered on one side by the untreated mat, the processed mat of the secondary fiber material is less likely to adhere to the teeth 238 of the evacuation roll. The plurality of teeth 238 of the evacuation roll 236 separate the untreated mat of the secondary fiber material and the processed mat of the secondary fiber material into individual streams of the secondary fiber material 232 mixed with the softening agent to form a mixed stream 235. The mixed stream 235 of the secondary fiber material and the softening agent flows through the nozzle 244 and merges with the meltblown fiber material streams 226, 228 in the forming zone 230 to form a composite stream 256 (e.g., similar to Figure 2 the apparatus 200 shown).

[0117] In some embodiments, two additional untreated pads of the secondary fiber material are included with the treated pad of the secondary fiber material. In such embodiments, the treated pad of the secondary fiber material (e.g., treated with a softening agent) is disposed between a first untreated pad of the secondary fiber material and a second untreated pad of the secondary fiber material (e.g., where the first untreated pad and the second untreated pad are not treated with a softening agent). Then, the first untreated pad of the secondary fiber material, the treated pad of the secondary fiber material, and the second untreated pad of the secondary fiber material are fed into the evacuation roll 236. Since both surfaces of the pad of the secondary fiber material that has been treated with the softening agent are covered by the untreated pads, the teeth 238 of the evacuation roll 236 first contact the untreated pads to reduce the likelihood that the treated pad of the secondary fiber material adheres to the teeth 238 of the evacuation roll. The plurality of teeth 238 of the evacuation roll 236 separate the first untreated pad of the secondary fiber material, the treated pad of the secondary fiber material, and the second untreated pad of the secondary fiber material into separate streams of the secondary fiber material 232 mixed with the softening agent to form a mixed stream 235. The mixed stream 235 of the secondary fiber material and the softening agent flows through the nozzle 244 and merges with the meltblown fiber material streams 226, 228 in the forming zone 230 to form a composite stream 256 (e.g., similar to Figure 2 the apparatus 200 shown).

[0118] Figure 7 Another apparatus 700 for forming a fibrous nonwoven structure 254 is shown in accordance with some embodiments. Figure 7 The apparatus 700 shown is similar to Figure 2 the apparatus 200 shown, except for the location of the softening agent manifold 290. In Figure 7 the same or similar reference numerals are used as for the apparatus 200 (and Figure 2 the apparatus 300 - 600 in Figures 3 to 6 to denote the same or similar features of the apparatus 400.

[0119] As in the Figure 2 apparatus 200 of Figure 7 the apparatus 700 of Figure 9 includes a softening agent manifold 290 having one or more openings 292 that discharge one or more softening agent streams 294. However, in the apparatus 700, the softening agent manifold 290 is positioned below the second meltblown die 218. In other words, in the apparatus 700, the softening agent manifold 290 is positioned at a height above the forming surface 258 that is less than the vertical forming distance (β) of the meltblown die (as

[0120] In addition, the softener manifold 290 of the apparatus 700 is oriented such that the softener stream 294 merges with the second meltblown fiber material stream 228 above the forming zone 230. Thus, in the apparatus 700, the second meltblown fiber material stream 228 and the softener stream 294 merge to form a mixed stream 235 (composed of the meltblown fiber material stream 220 and the softener). Then, the mixed stream 235 merges with the secondary fiber material stream 234 and the first meltblown fiber material stream 226 at the forming zone 230 to form a composite stream 256 (composed of the secondary fiber material 232, the meltblown fiber material 220, and the softener). The composite stream 256 is then deposited onto the forming surface 258 of the collection device to form the nonwoven web 254 (e.g., in the manner described with respect to Figure 2 the apparatus 200).

[0121] In addition, as Figure 7 shown, the softener manifold 290 in the apparatus 700 is positioned such that the softener stream 294 merges with the second meltblown fiber material 228 on the downstream side of the second meltblown fiber material stream 228, which is the side closer to the nonwoven web 254 and the forming surface 258. In other embodiments, the softener manifold 290 may be positioned and oriented such that the softener stream 294 merges with the second meltblown fiber material stream 228 on the upstream side of the second meltblown fiber material stream 228. In other embodiments, the softener manifold 290 may be positioned and oriented such that the softener stream 294 merges with the first meltblown fiber material stream 226 on the downstream side of the first meltblown fiber material stream 226. In other embodiments, the softener manifold 290 may be positioned and oriented such that the softener stream 294 merges with the first meltblown fiber material stream 226 on the upstream side of the first meltblown fiber material stream 226.

[0122] Figure 8 Another apparatus 800 for forming the fibrous nonwoven structure 254 according to some embodiments is shown. Figure 8 The apparatus 800 shown is similar to Figure 7 the apparatus 700 shown, except for the position of the softener manifold 290. The same or similar reference numerals are used in Figure 8 to denote the same or similar features of the apparatus 800 as those used for the apparatus 800 in Figure 8 and respectively for the apparatus 200, 600 in Figures 2 to 6 .

[0123] As in Figure 7 the apparatus 700, Figure 8The apparatus 800 includes a softener manifold 290 having one or more openings 292 that are oriented such that one or more softener streams 294 flowing out of the one or more openings 292 merge at an angle with other material streams (e.g., the secondary fiber material stream 234 and the meltblown fiber material streams 226, 228). However, in the apparatus 800, the softener manifold 290 is positioned and oriented such that the softener stream 294 merges with each of the secondary fiber material stream 234, the first meltblown fiber material stream 226, and the second meltblown fiber material stream 228 in the forming zone 230. In this manner, the various material streams 234, 226, 228, 294 all merge together in the forming zone 230 to form a composite stream 256.

[0124] As Figure 8 shown, the softener stream 294 discharged from the softener manifold 290 merges into the forming zone 230 on the side that is downstream of the longitudinal direction of the forming surface 258 (i.e., the side where the forming zone 230 is adjacent to the second meltblown die 218 and closer to the nonwoven material 254 on the forming surface 258).

[0125] It should be understood that the present disclosure is in no way limited to the above-described embodiments. In alternative embodiments, for example, a first meltblown die and a second meltblown die can be employed that extend substantially through the forming surface in a direction that is substantially transverse to the direction of movement of the forming surface. The die can likewise be arranged substantially vertically, i.e., aligned vertically with respect to the forming surface, such that the resulting meltblown fibers are blown directly downward 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 to Dunbar et al., which is hereby incorporated by reference in its entirety for all purposes. Additionally, although the above-described embodiments employ multiple meltblown dies to produce fibers of different sizes, a single die can also be employed. An example of such a process is disclosed in U.S. Patent No. 7,168,932 to Lassig et al., which is hereby incorporated by reference in its entirety for all purposes.

[0126] Example nonwoven web

[0127] Various nonwoven webs are formed and tested in accordance with aspects of the present disclosure to determine specific web characteristics, including softness, strength, and flexibility.

[0128] Using regarding Figure 2The described apparatus 200 forms a first set of exemplary nonwoven webs (PSD-10 and PSD-40). Accordingly, each of the first exemplary nonwoven webs (PSD-10 and PSD-40) includes a secondary fiber material, a meltblown fiber material, and a softening agent (e.g., nonwoven web 100 formed from secondary fiber material fibers 101, meltblown fiber material fibers 103, and softening agent 105, as Figure 1 depicted). In addition, each of the exemplary webs (PSD-10 and PSD-40) in the exemplary webs is formed using a process in which the softening agent is combined with the secondary fiber material stream to form a mixed stream (of the secondary fiber material and the softening agent), wherein the softening agent stream is combined with the secondary fiber material stream on a side of the secondary fiber material stream that is longitudinally downstream relative to the forming surface (e.g., as depicted for the apparatus 200 in Figure 2 ), and wherein the mixed stream is then combined with the meltblown fiber material stream to form a composite stream that is deposited onto the forming surface. Additionally, a control nonwoven web (Control 1) is formed using the same method but without using a softening agent.

[0129] Web examples PSD-10, PSD-40, and Control 1 are formed with a total basis weight of 70 gsm. The secondary fiber material used is a pulp mat supplied by International Paper (reeled ECF bleached southern pine softwood kraft fluff pulp treated with a defoamer and an antistatic agent, medically certified, FDA approved, and compliant with BfR) and accounts for approximately 70 wt% (i.e., 49 gsm) of each exemplary nonwoven web. The meltblown fiber material used is a high melt flow rate metallocene-based polypropylene homopolymer (Achieve TM Advanced PP6945G1 manufactured by ExxonMobil) and accounts for approximately 30 wt% (i.e., 21 gsm) of each exemplary nonwoven web. The softening agent used is silicone (WACKER HC 3502), and is provided in different amounts (approximately 0.000 - 0.315 gsm, or 0 - 40 lbs / MT pulp) in each exemplary nonwoven web. The softening agent manifold includes twelve openings, each having a diameter of 0.02 inches, and each opening is spaced 1.0 inches apart from one another in a linear row. The specific characteristics of web examples PSD-10, PSD-40, and Control 1 are shown in Table 1 below.

[0130] Table 2 reports the performance characteristics of exemplary nonwoven webs PSD-10, PSD-40, and Control 1. More specifically, the strength of exemplary nonwoven webs PSD-10, PSD-40, and Control 1 is tested according to the CDT and MDT strength test methods described herein, and the softness and flexibility are tested according to the EMTEC TSA softness and flexibility test methods described herein.

[0131]

[0132] Table 1

[0133]

[0134] Table 2

[0135] Using the apparatus 300 described Figure 3 a second set of exemplary nonwoven webs (PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80) are formed. Accordingly, each of the exemplary nonwoven webs PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, and PSU-80 includes a secondary fiber material, a meltblown fiber material, and a softening agent (e.g., a nonwoven web 100 formed of secondary fiber material fibers 101, meltblown fiber material fibers 103, and softening agent 105, as Figure 1 depicted). Additionally, each of the exemplary webs (PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80) is formed using a process in which the softening agent is combined with the secondary fiber material stream to form a combined stream (of secondary fiber material and softening agent), where the softening agent stream is combined with the secondary fiber material stream on a side of the secondary fiber material stream that is longitudinally upstream relative to the forming surface (e.g., as depicted for the apparatus 300 in Figure 3 ), and where the combined stream is then combined with the meltblown fiber material stream to form a composite stream that is deposited onto the forming surface. Additionally, a control nonwoven web (Control 2) is formed that does not use the softening agent.

[0136] Examples PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80, and Control 2 were formed with a total basis weight of 70 gsm. The secondary fiber material used was a pulp mat supplied by Georgia-Pacific (a roll of ECF bleached southern pine softwood kraft fluff pulp treated with a debonder and an antistatic agent, medically certified, FDA approved, and compliant with BfR) and accounted for approximately 70 wt% (i.e., 49 gsm) of each example nonwoven web. The meltblown fiber material used was a high melt flow rate metallocene-based polypropylene homopolymer (Metocene MF650X manufactured by LyondellBassell) and accounted for approximately 30 wt% (i.e., 21 gsm) of each example nonwoven web. The softening agent used was silicone (WACKER HC 3502), and was provided in different amounts (approximately 0.000 - 0.605 gsm, or 0 - 80 lbs / MT pulp) in each example nonwoven web. The softening agent manifold included twelve openings, each with a diameter of 0.02 inches, and each opening was spaced 1.0 inches apart in a linear row. The specific characteristics of example webs PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80, and Control 2 are shown in Table 3 below.

[0137] Table 4 reports the performance characteristics of example nonwoven webs PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80, and Control 2. More specifically, the strength of example nonwoven webs PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80, and Control 2 was tested according to the CDT and MDT strength test methods described herein, and the softness and flexibility were tested according to the EMTEC TSA softness and flexibility test methods described herein.

[0138]

[0139] Table 3

[0140]

[0141]

[0142] Table 4

[0143] Using with respect to Figure 7The apparatus 700 described forms a third set of exemplary nonwoven webs (MSD-10, MSD-20, MSD-40). Accordingly, each of the exemplary nonwoven webs MSD-10, MSD-20, and MSD-40 includes a secondary fiber material, a meltblown fiber material, and a softening agent (e.g., a nonwoven web 100 formed from secondary fiber material fibers 101, meltblown fiber material fibers 103, and softening agent 105, as Figure 1 depicted). Additionally, each of the exemplary webs (MSD-10, MSD-20, MSD-40) in the example is formed using a process in which the softening agent is combined with a first meltblown fiber material stream to form a mixed stream (of meltblown fiber material and softening agent), where the softening agent stream is combined with the meltblown fiber material stream on a side of the meltblown fiber material stream that is longitudinally downstream relative to the forming surface (e.g., as depicted for the apparatus 700 in Figure 7 ), and where the mixed stream is then combined with a secondary fiber material stream (and a second meltblown fiber material stream) to form a composite stream that is deposited onto the forming surface. Additionally, the control 2 web that did not use a softening agent as discussed above is again used as a control web.

[0144] Exemplary MSD-10, MSD-20, MSD-40, and Control 2 are formed with a total basis weight of 70 gsm. The secondary fiber material used is a pulp pad supplied by Georgia-Pacific (reelable ECF bleached southern pine softwood kraft fluff pulp treated with a defoamer and an antistatic agent, medically certified, FDA approved, and compliant with BfR) and accounts for approximately 70 weight percent (i.e., 49 gsm) of each exemplary nonwoven web. The meltblown fiber material used is a high melt flow rate metallocene-based polypropylene homopolymer (Metocene MF650X manufactured by LyondellBassell) and accounts for approximately 30 weight percent (i.e., 21 gsm) of each exemplary nonwoven web. The softening agent used is a silicone (WACKER HC 3502), and is provided in different amounts (approximately 0.000 - 0.302 gsm, or 0 - 40 lbs / MT pulp) in each exemplary nonwoven web. The softening agent manifold includes twelve openings, each having a diameter of 0.02 inches, and each opening is spaced 1.0 inches apart from one another in a linear row. The specific characteristics of exemplary webs MSD-10, MSD-20, MSD-40, and Control 2 are shown in Table 5 below.

[0145] Table 6 reports the performance characteristics of exemplary nonwoven webs MSD-10, MSD-20, MSD-40, and Control 2. More specifically, the strength of exemplary nonwoven webs MSD-10, MSD-20, MSD-40, and Control 2 was tested according to the CDT and MDT strength test methods described herein, and the softness and flexibility were tested according to the EMTEC TSA softness and flexibility test methods described herein.

[0146]

[0147] Table 5

[0148]

[0149] Table 6

[0150] Using the apparatus 800 described with respect to Figure 8 a fourth set of exemplary nonwoven webs (FZD-10, FZD-40) was formed. Accordingly, each of the exemplary nonwoven webs FZD-10 and FZD-40 includes a secondary fiber material, a meltblown fiber material, and a softening agent (e.g., a nonwoven web 100 formed from secondary fiber material fibers 101, meltblown fiber material fibers 103, and softening agent 105, as Figure 1 depicted). Additionally, each of the exemplary webs in the exemplary webs (FZD-10, FZD-40) was formed using a process in which the softening agent is combined with a secondary fiber material stream and two meltblown fiber material streams in a forming zone to form a composite stream (of secondary fiber material, meltblown fiber material, and softening agent), wherein the softening agent stream is combined with the material streams on a side of the forming zone longitudinally downstream relative to the forming surface (e.g., as depicted with respect to the apparatus 800 in Figure 8 ), and wherein the composite stream is deposited onto the forming surface. Additionally, Control 2 web, which did not use a softening agent as discussed above, was again used as a control web.

[0151] Formed were Example FZD-10, FZD-40, and Control 2 having a total basis weight of 70 gsm. The secondary fiber material used was a pulp mat supplied by Georgia-Pacific (a reel of ECF bleached southern pine softwood kraft fluff pulp treated with a defoamer and an antistatic agent, medically certified, FDA approved, and compliant with BfR) and accounted for approximately 70 wt% (i.e., 49 gsm) of each example nonwoven web. The meltblown fiber material used was a high melt flow rate metallocene-based polypropylene homopolymer (Metocene MF650X manufactured by LyondellBassell) and accounted for approximately 30 wt% (i.e., 21 gsm) of each example nonwoven web. The softener used was silicone (WACKER HC 3502), and was provided in different amounts in each example nonwoven web (approximately 0.000 - 0.302 gsm, or 0 - 40 lbs / MT pulp). The softener manifold used included four spray nozzles, each spray nozzle being a McMaster-Carr drip-proof flat spray nozzle with a diameter of 0.02 inches (part number 4846T112), and each spray nozzle being spaced 4.0 inches apart from each other in a linear row. The specific characteristics of Example webs FZD-10, FZD-40, and Control 2 are shown in Table 7 below.

[0152] Table 8 reports the performance characteristics of Example nonwoven webs FZD-10, FZD-40, and Control 2. More specifically, the strength of Example nonwoven webs FZD-10, FZD-40, and Control 2 was tested according to the CDT and MDT strength test methods described herein, and the softness and flexibility were tested according to the EMTEC TSA softness and flexibility test methods described herein.

[0153]

[0154] Table 7

[0155]

[0156] Table 8

[0157] Using an apparatus similar to apparatus 600 described with respect to Figure 6 formed was a fifth group of example webs (EXP-40, EXP-60, EXP-80), but without a softener manifold. Instead, a pulp supply pretreated with a softener was used as the secondary fiber material and was supplied to the evacuation roll for conversion into nonwoven web samples (as with Figure 6The remaining aspects of the apparatus 600 shown are the same). Thus, each of the exemplary nonwoven webs EXP-40, EXP-60, and EXP-80 includes a secondary fiber material, a meltblown fiber material, and a softening agent (e.g., a nonwoven web 100 formed from secondary fiber material fibers 101, meltblown fiber material fibers 103, and softening agent 105, as Figure 1 depicted). Additionally, a control nonwoven web (Control 3) without the use of a softening agent was formed.

[0158] Exemplary EXP-40, EXP-60, EXP-80, and Control 3 with a total basis weight of 70 gsm were formed. The secondary fiber material used was a pulp pad supplied by International Paper (a roll of ECF bleached southern pine softwood kraft fluff pulp treated with a defoamer and an antistatic agent, medically certified, FDA approved, and compliant with BfR) and accounted for approximately 73 wt% (i.e., 51 gsm) of each exemplary nonwoven web. The meltblown fiber material used was a high melt flow rate metallocene-based polypropylene homopolymer (Achieve TM Advanced PP6945G1 manufactured by ExxonMobil) and accounted for approximately 27 wt% (i.e., 19 gsm) of each exemplary nonwoven web. The softening agent used was silicone (WACKER HC 3502) and was used to pretreat the pulp pad in different amounts (approximately 0.000 - 0.630 gsm, or 0 - 80 lbs / MT pulp). The specific characteristics of the exemplary webs EXP-40, EXP-60, EXP-80, and Control 3 are shown in Table 9 below.

[0159] Table 10 reports the performance characteristics of the exemplary nonwoven webs EXP-40, EXP-60, EXP-80, and Control 3. More specifically, the strength of the exemplary nonwoven webs EXP-40, EXP-60, EXP-80, and Control 3 was tested according to the MDT strength test method described herein, and the softness and flexibility were tested according to the EMTEC TSA softness and flexibility test method described herein.

[0160]

[0161]

[0162] Table 9

[0163]

[0164] Table 10

[0165] As seen in Tables 1 to 10, compared to the control webs without silicone (i.e., Control 1, Control 2, Control 3), the exemplary nonwoven webs using silicone produced according to the methods and apparatuses described herein (i.e., PSD-10, PSD-40, PSU-2.5, PSU-5, PSU-10, PSU-20, PSU-40, PSU-80, MSD-10, MSD-20, MSD-40, FZD-10, FZD-40, EXP-40, EXP-60, EXP-80) generally have improved softness values (TS7). Additionally, the exemplary nonwoven webs in Tables 1 to 10 indicate that as more silicone is added to the nonwoven blend, the softness (TS7) of the nonwoven web generally improves. Tables 1 to 10 also show that the exemplary nonwoven webs exhibit improved flexibility (mm / N) and maintain sufficient strength (gf).

[0166] Additionally, the exemplary nonwoven webs surprisingly show a sufficient combination of softness, flexibility, and strength while using a relatively small amount of silicone. In many instances, a softness value of less than 6.0 (TS7) was achieved using 0.079 gsm (10 lb / MT pulp) of silicone while maintaining sufficient strength and flexibility. In further instances, a softness value of less than 5.0 (TS7) was achieved using 0.302 gsm (40 lb / MT pulp) (or less) of silicone while maintaining sufficient strength and flexibility.

[0167] For the method in which the softener stream is combined with the secondary fiber material stream (to form a mixed stream of softener and secondary fiber material), the applicant surprisingly found that combining the softener with the secondary fiber material stream on the longitudinal downstream side of the secondary fiber material stream relative to the forming surface (e.g., as described regarding Figure 2 the apparatus 200 therein) produces a nonwoven web with improved softness (TS7). The improved softness values obtained by applying the softener to the downstream side of the secondary fiber material stream are reflected in the data of Tables 1 and 2 (by comparison with the softness values obtained by applying the softener to the upstream side of the secondary fiber material stream as shown in Tables 3 and 4).

[0168] Absorbent article, such as a wet wipe

[0169] In various embodiments, the nonwoven web structures disclosed herein (e.g., Figure 1 the nonwoven web 100 of Figures 2 to 8The nonwoven web 254) can be used as a substrate in wet wipe products, particularly wet wipe products suitable for infants. In such embodiments, a liquid formulation is applied and absorbed into the substrate. The liquid formulation can include various components that provide desired wipe characteristics (e.g., chemicals diluted (e.g., in water) such as preservatives and fragrances). In various embodiments, the liquid formulation can include water, emollients, surfactants, fragrances, preservatives, chelating agents, pH buffers, or combinations thereof, as is well known to those skilled in the art. The liquid can also contain lotions, drugs, and / or other active agents.

[0170] The amount of liquid 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 wet wipes, and the intended end use of the wet wipes. Generally, based on the dry weight of the wipe, each wet wipe can contain from about 150 to about 600 weight percent and desirably from about 250 to about 450 weight percent of liquid to improve wiping. In a particular aspect, the amount of liquid contained in the wet wipe is from about 250 to about 300 weight percent 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 not function adequately. If the amount of liquid is greater than the above range, the wet wipe may be oversaturated and wet, and the liquid may pool at the bottom of the container.

[0171] The shape of each wet wipe can be generally rectangular and can have any suitable unfolded width and length. For example, the wet wipe can have an unfolded length of from about 2.0 cm to about 80.0 cm and desirably from about 10.0 cm to about 25.0 cm and an unfolded width of from about 2.0 cm to about 80.0 cm and desirably from about 10.0 cm to about 25.0 cm. Typically, each individual wet wipe is arranged in a folded configuration and stacked one on top of the other, or is a continuous strip of material with perforations to provide a stack of wet wipes. The stack of wet wipes can be placed inside a container such as a plastic bucket and arranged in a stack for dispensing to provide a wet wipe package for final sale to the consumer.

[0172] As disclosed herein, applying functional chemicals (e.g., softeners) during the nonwoven web (substrate) forming process has several advantages, including improved substrate softness, improved substrate hold, and other improved substrate characteristics. Using the methods described herein, the applicant has surprisingly found that by applying a softener during the formation of the nonwoven web (substrate), a suitable softness (TS7) can be obtained without including a softener in the liquid formulation added to the substrate to form the wet wipe. In other words, in various embodiments, the nonwoven web itself (substrate) has softness characteristics such that the liquid formulation applied to the substrate does not contain a softener.

[0173] In addition, the Applicant has surprisingly found that the methods described herein are capable of achieving a suitable softness value using significantly less softening agent (compared to wet wipes that do not use a softening agent during substrate formation but include it in the liquid formulation). For example, the Applicant has surprisingly found that applying a softening agent during substrate formation (as shown and described herein with respect to apparatus 200 - 800) can produce a nonwoven web with suitable softness characteristics (and sufficient strength and flexibility) using approximately 55% less softening agent. For example, for a comparable web basis weight, a nonwoven web prepared according to the methods herein using approximately 0.302 to 0.315 gsm of silicone will have substantially the same softness characteristics as a conventional wet wipe applied via a liquid formulation with approximately 0.567 gsm of silicone. Thus, as described herein, various embodiments enable more efficient manufacture of nonwoven web materials and wet wipe products made from such nonwoven web materials.

[0174] In certain embodiments, when a softening agent is added to the substrate during the forming process and the substrate is then used to form a wet wipe product, a wider range of liquid formulations can be added to the substrate. For example, in certain embodiments, the improved softness of the substrate can allow the liquid formulation to be free of a softening agent, which is advantageous for using a wider range of functional chemicals while maintaining the stability of the liquid formulation (e.g., chemicals that would otherwise compromise the stability of the liquid formulation if included with a softening agent). Thus, various embodiments of the apparatuses, systems, and methods disclosed herein provide more flexible options for producing wet wipes and other nonwoven web materials with various liquid formulation chemicals, which results in improved consumer - desired characteristics (e.g., softness, mildness, and strength) in the wet wipe products.

[0175] The nonwoven web of the present disclosure can alternatively be used in a variety of articles. For example, the web can be incorporated into "absorbent articles" capable of absorbing water or other fluids. Some examples of absorbent articles include, but are not limited to, personal care absorbent articles such as diapers, training pants, absorbent underpants, incontinence articles, feminine hygiene products (e.g., sanitary napkins), swimwear, and the like; medical absorbent articles such as garments, fenestration materials, padding, mattresses, bandages, absorbent drapes, and medical wipes; apparel articles; pockets, and the like. The materials and methods for forming such articles are well known to those skilled in the art. Several examples of such absorbent articles are described in U.S. Patent No. 5,649,916 to DiPalma et al., U.S. Patent No. 6,110,158 to Kielpikowski, and U.S. Patent No. 6,663,611 to Blaney et al., which are hereby incorporated by reference in their entirety for all purposes. Additional other suitable articles are described in U.S. Patent Application Publication No. 2004 / 0060112A1 to Fell et al. and U.S. Patent No. 4,886,512 to Damico et al., U.S. Patent No. 5,558,659 to Sherrod et al., U.S. Patent No. 6,888,044 to Fell et al., and U.S. Patent No. 6,511,465 to Freiburger et al., all of which are hereby incorporated by reference in their entirety for all purposes. When used in absorbent articles, the nonwoven web of the present disclosure can form a component of the absorbent core or any other absorbent component of absorbent articles well known in the art.

[0176] Although various implementations have been described in detail herein, it should be understood that those skilled in the art, upon obtaining an understanding of the foregoing, can readily conceive of alterations, variations, and equivalents to these implementations. Additionally, it should be noted that any given range presented herein is intended to include any and all sub-included ranges. For example, a range of 45 - 90 also includes 50 - 90; 45 - 80; 46 - 89, etc.

[0177] EMTEC TSA softness and flexibility test method

[0178] The softness and flexibility (stiffness) of the nonwoven web are measured using an EMTEC Tissue Softness Analyzer ("TSA") (Emtec Electronic GmbH, Leipzig, Germany). Softness is measured according to the TS7 value, while flexibility is measured in mm / N.

[0179] The TSA includes a rotor with vertical blades that rotate over the test piece, thereby applying a defined contact pressure. The contact between the vertical blades and the test piece generates vibrations that are sensed by vibration sensors. The sensors then transmit signals to a personal computer (PC) for processing and display. The signals are displayed in a frequency spectrum. To measure the TS7 value, the blade is pressed against the sample with a load of 100 mN, and the rotational speed of the blade is 2 revolutions per second.

[0180] To measure the TS7 value, frequency analysis is performed in the range of approximately 1 kHz to 10 kHz, and the peak amplitude that appears at 7 kHz is recorded as the TS7 value. The TS7 value represents the softness of the sample, and a lower amplitude is associated with a softer sample. The unit of the TS7 value is dB V2 root mean square (rms).

[0181] Test samples are prepared by cutting circular samples with a diameter of 112.8 mm. Before completing the TSA test, all samples are allowed to equilibrate for at least 24 hours under TAPPI standard temperature and humidity conditions. To measure the softness of the non-wire side (NWS), the sample is placed in the TSA with the air side of the sample facing up (the side of the sample collected on the forming line facing down). To measure the softness of the wire side (WS), the sample is placed in the TSA with the air side of the sample facing down (the side of the sample collected on the forming line facing up). The sample is fixed, and the measurement is started via the PC. The PC records, processes, and stores all data according to the standard TSA protocol. The reported value is the average of 5 repeated tests, with each test using a new sample. Sample

[0182] As used herein, the term flexibility (or stiffness parameter (D)) refers to the output of the TSA in units of mm / N. Generally, the flexibility value (reported in units of mm / N) is a measure of the deformation of the sample under a specified load. Flexibility data is collected when a rotor with blades presses against the test piece with two different forces in two cycles. Force 1 (100 mN) and then force 2 (600 nM) are applied as pre-elongations to the test piece to measure the displacement D.

[0183] The TSA softness and flexibility test method calibrates the TSA according to the instructions of EMTEC using a 1-point calibration method and an appropriate reference standard (e.g., "Reference 2 sample" or equivalent, available from EMTEC).

[0184] CDT and MDT strength test methods

[0185] The CDT strength test method measures the peak load value, i.e., the maximum force generated by the sample when the sample is pulled to fracture in the cross direction (CD). The sample is cut into 25 mm wide and 152 mm long using a die cutter or a sample cutter such as a JDC Precision Sample Cutter (Thwing-Albert Instrument Company, Philadelphia, Pa., model JDC 3-10, serial number 37333) and is conditioned at 23 ± 2 °C and 50 ± 5% relative humidity for at least 4 hours before testing and is tested under the same environmental conditions. The length dimension of the sample should extend in the cross direction (CD) of the web from which the sample is cut. The CDT strength value is the peak load (cross tensile strength) in grams force when the sample is pulled to rupture. More specifically, the CDT strength value is the peak load when the sample is pulled with a force oriented in a direction crossing the longitudinal orientation of the sample.

[0186] The MDT strength test method measures the peak load value, i.e., the maximum force generated by the sample when the sample is pulled to fracture in the machine direction (MD). The sample is cut into 25 mm wide and 152 mm long using a die cutter or a sample cutter such as a JDC Precision Sample Cutter (Thwing-Albert Instrument Company, Philadelphia, Pa., model JDC 3-10, serial number 37333) and is conditioned at 23 ± 2 °C and 50 ± 5% relative humidity for at least 4 hours before testing and is tested under the same environmental conditions. The length dimension of the sample should extend in the machine direction (MD) of the web from which the sample is cut. The MDT strength value is the peak load (machine tensile strength) in grams force when the sample is pulled to rupture. More specifically, the MDT strength value is the peak load when the sample is pulled with a force oriented in the machine direction of the sample.

[0187] The tensile strength testers used for the CDT and MDT strength test methods are MTS Standards 41 or 43 and MTS TestSuite Elite TM (MTS Systems Corp., Research Triangle Park, NC). A load cell is selected such that the peak load value falls between 10% and 90% of the load cell full scale load - depending on the strength of the test sample, a 50 Newton or 100 Newton load cell may typically be appropriate. The gauge length is 76 mm, and the jaw width is 76 mm, with a height of approximately 12.7 mm. The chuck speed is 305 mm / minute, and the break sensitivity is set at 70%.

[0188] Place the sample in the jaws of the instrument and center it vertically and horizontally with the longer dimension parallel to the load application direction. The fixture is operated using a pneumatic action and is coated with rubber. Then the test is started and ended when the sample breaks. The peak load is determined and reported as the CDT (or MDT) strength value of the sample, accurate to 0.1 gf. Five (5) representative samples are tested and the arithmetic mean of all individual samples tested is the tensile strength of the product.

[0189] Example embodiment

[0190] This document provides multiple example embodiments. However, it should be understood that various modifications can be made without departing from the spirit and scope disclosed herein. As used in the specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a / an" and "the" include plural referents. As used herein, the terms "comprising" and its variants are used synonymously with the term "including" and its variants, and are open-ended, non-restrictive terms. Although the terms "including" and "comprising" are used herein to describe various embodiments, the terms "consisting essentially of" and "consisting of" can be used in place of "including" and "comprising" to provide more specific embodiments and are also disclosed.

[0191] Disclosed are materials, systems, devices, methods, compositions, and components that can be used in, can be used in combination with, can be used to prepare, or are products of the disclosed methods, systems, and devices. These and other components are disclosed herein, and it should be understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed, although specific references to each various individual and collective combination and arrangement of these components may not be explicitly disclosed, each of these components is specifically contemplated and described herein. For example, if a device is disclosed and discussed, every combination and arrangement of the device is disclosed herein, and unless specifically stated to the contrary, possible modifications are specifically envisioned. Similarly, any subset or combination of these is also specifically envisioned and disclosed. This concept applies to all aspects of the present disclosure, including but not limited to the steps in methods using the disclosed systems or devices. Thus, if there are multiple additional steps that can be performed, it should be understood that each of these additional steps can be performed with any particular method step or combination of method steps of the disclosed method, and each such combination or subset of combinations is specifically envisioned and should be considered disclosed.

Claims

1. A fibrous nonwoven structure, comprising: at least one meltblown fiber material having an average diameter of about 0.5 to 50 μm; and at least one secondary fiber material, wherein the weight ratio of the meltblown fiber material to the secondary fiber material is between 10 / 90 and 60 / 40; wherein the fibrous nonwoven structure has a TS7 value of less than 7.

0.

2. The fibrous nonwoven structure according to claim 1, further comprising a softening agent.

3. The fibrous nonwoven structure according to claim 1, wherein the softening agent comprises silicone.

4. The fibrous nonwoven structure according to claim 1, wherein the fibrous nonwoven structure has a TS7 value of less than about 6.

0.

5. The fibrous nonwoven structure according to claim 4, wherein the fibrous nonwoven structure has a TS7 value of less than about 5.

0.

6. The fibrous nonwoven structure according to claim 1, wherein the weight ratio of the softening agent to the secondary fiber material is in the range of 10 lb / MT to 80 lb / MT.

7. The fibrous nonwoven structure according to claim 6, wherein the weight ratio of the softening agent to the secondary fiber material is in the range of 20 lb / MT to 60 lb / MT.

8. The fibrous nonwoven structure according to claim 7, wherein the weight ratio of the softening agent to the secondary fiber material is 40 lb / MT.

9. The fibrous nonwoven structure according to claim 1, wherein the meltblown fiber material comprises a polymer.

10. The fibrous nonwoven structure according to claim 9, wherein the polymer comprises polypropylene.

11. The fibrous nonwoven structure according to claim 9, wherein the polymer comprises polyethylene.

12. The fibrous nonwoven structure according to claim 1, wherein the secondary fiber material comprises wood pulp.

13. The fibrous nonwoven structure according to claim 1, wherein the weight ratio of the meltblown fiber material to the secondary fiber material is in the range of 20 / 80 to 60 / 40.

14. The fibrous nonwoven structure according to claim 13, wherein the weight ratio of the meltblown fiber material to the secondary fiber material is in the range of 25 / 75 to 40 / 60.

15. The fibrous nonwoven structure according to claim 14, wherein the weight ratio of the meltblown fiber material to the secondary fiber material is 30 / 70.

16. The fibrous nonwoven structure according to claim 1, wherein the fibrous nonwoven structure has a flexibility between about 2.5 mm / N and 3.5 mm / N.

17. The fibrous nonwoven structure according to claim 16, wherein the fibrous nonwoven structure has a flexibility between about 2.7 mm / N and 3.1 mm / N.

18. The fibrous nonwoven structure according to claim 1, wherein the fibrous nonwoven structure has a transverse tensile strength between about 200 gf and 400 gf.

19. The fibrous nonwoven structure according to claim 18, wherein the fibrous nonwoven structure has a transverse tensile strength between about 250 gf and 350 gf.

20. The fibrous nonwoven structure according to claim 1, wherein the fibrous nonwoven structure has a longitudinal tensile strength between about 400 gf and 860 gf.

21. The fibrous nonwoven structure according to claim 20, wherein the fibrous nonwoven structure has a longitudinal tensile strength between about 400 gf and 550 gf.

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