JP2004533344A - Fluid treatment complex - Google Patents

Abstract

It includes a number of corrugated strands of compression resistant material and one or more sheets of porous material bonded to the strands along its length at sheet bonding locations, with several strands between these sheet bonding locations. A composite fabric for dewatering a high solids content fluid material having an arcuate portion protruding from a strand. The sheet-like composite is incorporated into those that need to dewater high solids content fluids, such as disposable garments such as diapers and training pants.

Description

【Technical field】
[0001]
The present invention relates to liquid permeable fluid treated nonwoven composite fabrics for use in disposable absorbent articles such as filtration, fluid transfer and absorption, for example, diapers, adult incontinence products, sanitary napkins and the like. The invention further relates to a method for producing such a liquid-permeable composite fabric.
[Background Art]
[0002]
For example, from EP 963 747, it is desirable to provide a fluid handling member for a disposable absorbent article that allows the passage of liquids such as urine while collecting and retaining low viscosity, high solids materials such as feces. It is also known. In order to treat feces of low viscosity, the patent document proposes a structure in which the fluid-permeable support comprises a plurality of woven fibers projecting outwardly from the support. As the support, various materials such as a nonwoven web, a breathable film, a microporous film, a perforated nonwoven web, and the like are described. The woven fibers in the support member generally extend more than 1 mm, preferably higher, than the support member. The individual fibers are 15 to 30 denier and are woven in arcuate form at regular intervals. The woven fiber is 1cm ^Two It provides a laminate composite structure having a compression resistance of at least 30% when applied at a pressure of about 1,000 Newtons per hour, and most preferably at least 50% when applied. Similarly, the material can return to its shape after receiving this pressure, recovering to at least 50-85% after about 30 seconds. The fluid treatment member minimizes the amount of low viscosity feces on the wearer's skin, prevents fecal migration, separates feces into solid and liquid components, and transfers liquid components to the underlying absorber structure It is to let.
[0003]
A similar structure is described in U.S. Patent No. 5,705,249. The composite material described in this patent includes a non-woven fabric with a filament having a diameter of 0.05 to 5 mm attached. The filaments can be preformed into a nonwoven or extruded directly. Thereafter, the filaments are intermittently bonded to the nonwoven fabric, resulting in a bulge created by the elastic deformation of unbonded large diameter filaments. These filaments separate the nonwoven from the wearer's skin. However, there is no description of fecal treatment for this material. This material is designed solely to increase wearer comfort by separating the liquid absorbing layer or fluid transfer nonwoven from the wearer's skin.
[0004]
U.S. Pat. No. 5,976,665 describes another approach to address the problems faced by the '595,249 patent. The nonwoven fluid transfer layer or absorber is separated from the wearer's skin by attaching a corrugated perforated film or nonwoven. The corrugated material is formed with a series of crests and troughs. The crests contact the wearer's skin and reduce the perceived wetness of the article. However, the patent states that the corrugated structure is also useful for treating solid emissions in diapers and menstrual discharges in sanitary products by trapping solids in the valley. The corrugated layer is corrugated between the annealed surfaces of two interfitting corrugated cylinders, for example, thermally bonded to the underlying layer.
[0005]
In the filtration zone, it is known to provide a material such as a net to the surface of the porous filter to dewater the high solids content material. Such an approach is described in U.S. Patent No. 5,776,567, in which multilayer laminates of flexible filter materials are separated by a polymer network that acts as a dewatering layer of high solids content material. The filter and nesting material are simply stacked on top of each other and placed on the assembly device.
[0006]
EP 976 375 describes a stool treatment member having a material structure similar to that described in the above-mentioned 5,976,665 patent. A sheet of fiber, preferably a nonwoven web, is corrugated and attached to an additional liquid permeable web. For example, a nonwoven sheet of fiber is provided between the mesh mating portions of the mating corrugations and bonded to the second nonwoven web by thermal bonding of the corrugated nonwoven. Additional fibers are attached to the top of the corrugated web.
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0007]
While these various designs for fecal and fluid treatment members are advantageous, they are flexible, allow for good bonding between the separation member and the fluid transfer member, create a low outer surface contact area, and / or There is a need for methods and materials that perform at least one or more of directly manufacturing fluid treatment components that can function to efficiently separate high solids materials from liquids.
[Means for Solving the Problems]
[0008]
The present invention provides an improved fluid treatment composite including multiple corrugated strands of elastic material and one or more sheets of porous material intermittently bonded to the corrugated strands and a method of making the same. The corrugated strand has an arcuate portion protruding from the porous material between portions of the strand bonded to the porous material. These corrugated strands are resistant to compression. These fluid treatment complexes offer advantages when used for draining disposable clothing or high solids content fluids such as diapers, training pants, adult incontinence briefs or sanitary napkin products.
[0009]
The present invention also provides a novel method of making a fluid treatment composite. The fluid treatment complex is also well configured to be simple and inexpensive to manufacture for the desired end use. The method also provides a flexible versatility to select the properties of a fluid treatment complex that is manufactured without significant modifications to the equipment.
[0010]
According to the present invention, (1) providing at least a sheet of a porous material (eg, a perforated polymer film, or a sheet of woven natural or polymer fibers, or a cohesive nonwoven web of natural or polymer fibers); Extruding substantially parallel longitudinal strands at intervals of an elastic molten thermoplastic material (eg, polyolefin) upon cooling; and (3) projecting in the same direction from the anchor site at intervals of the extruded strands. Forming an extruded strand with an arcuate portion; and (4) extruding to form a porous laminate material with an extruded strand arcuate portion projecting outwardly from the porous material. Attaching the anchor portion of the bent strand. .
[0011]
In this manner, a novel fluid treatment composite is provided that includes multiple corrugated strands of elastic thermoplastic material extending in substantially parallel, spaced-apart relation. The corrugated strand has an anchor site bonded to the longitudinally spaced sections of the porous material at a first strand bonding location. The strand has an arcuate portion projecting between the strand bonding locations.
[0012]
Stretching the strands between the opposing corrugated members flattens the strands to form a corrugation having an arcuate portion. When bonded to the porous material at the bonding location, the spaced anchor sites are further flattened or jagged along portions of the strand surface proximate the anchor sites. The solidified strand generally has a uniform morphology along its length, but at the bonding location, a different thermal history is seen and has a slightly different morphology. The strand is pressed against the surface of the porous material at the bonding location of the anchor site, and the width of the strand is made larger between the opposing elongated sides of the strand along the bonding location than at the bonding location to create a porous Very tight attachment between material and strand.
[0013]
In the above-described method of forming a fluid treatment composite, the forming step includes: (1) a first and second substantially cylindrical corrugated members each having an axis and defining a perimeter of the corrugated member. Ridges having an outer surface and having a space between the ridges adapted to receive a portion of the ridge of another corrugated member in mating relationship with a number of strand materials in between. Providing a defining corrugated member; (2) attaching the corrugated member in an engagement relationship parallel to the axis of the ridge portion and the axis; and (3) rotating the at least one corrugated member; (4) extruding a plurality of strand materials onto at least one corrugated member and supplying the strands between the mating portions of the ridge such that the strand material is substantially along the periphery of the first corrugated member; Forming an arcuate portion of the strand material in the space between the ridge of the first corrugation member and the anchor portion of the strand material along the outer surface of the ridge of the corrugation member of (5); Holding a predetermined distance along one circumference of the first corrugated member after moving past the mating portion of the ridge (can be performed in any order, some steps may be May be omitted). The extruding step includes providing an extruder that extrudes spaced strands of molten thermoplastic material through a die having spaced openings and within a predetermined distance along a perimeter of the first corrugated member. Is included. By this method, the strand is easily extruded by changing the pressure of the extruder from which the strand is extruded (eg, changing the screw speed or type of extruder) and / or changing the speed at which the first corrugated member moves. (E.g., for a given speed output from an extruder, increasing the speed of the moving corrugations reduces the diameter of the strands and decreasing the speed of the corrugations moves the The diameter increases). Similarly, in dies where the extruder extrudes thermoplastic material, the die plate on which the rows of spaced openings through which the strands of molten thermoplastic material are extruded can be easily modified. Such die plates with different diameters and different spacing openings can be relatively easily formed by electrical discharge machining or other known methods that provide different spacings and diameters to the strands. Using different spacings and / or diameters for the openings along the length of the row of openings in one die plate, for example, with greater or less compression as required for a given end use A fluid treatment composite having resistance can be manufactured. Different effects can be achieved by shaping or modifying the die to form hollow strands, non-round shaped strands (eg, square or cross-shaped) or two- or multi-component strands.
[0014]
As described above, the fluid treatment composite according to the present invention is further thermally bonded to a vertically spaced portion of the porous material at a second sheet bonding location along a corresponding second elongated surface portion. A second set of strand material having an anchor portion and an arcuate portion protruding from a second elongated surface portion of the elastic strand between the second sheet bonding locations may be included.
[0015]
Using the method described above, such a second set of strand materials can be provided to the fluid treatment composite in at least two different ways. One approach is to project in the same direction from the second set of strand material spaced anchor sites and to move the second set of strand material spaced anchor sites apart from the first set of strand material gaps. Forming a second set of strand material to have an arcuate portion proximate to the open anchor portion. At this time, the arcuate portions of the first and second sets of strand material protrude in opposite directions, such that the porous material is bonded to the first and second sets of strand materials at the same time by the first and second sets of strand materials. A second set of strand material is supplied between the anchor sites. Another method is to provide a second set of strand materials after the first set of strand materials is bonded to the porous material, and to provide a second set of strand materials spaced apart from the porous material. Bonding to at least some of the bond parts.
[0016]
The porous material of the fluid treatment composite can be any porous material that allows a fluid to pass through the porous material and, optionally, into and through the porous material. The porous material may be (1) a polymer perforated film (eg, polypropylene, polyethylene or polyester), (2) a conventional woven, knitted, stitch bonded or similar fibrous material, (3) a non-woven fibrous material, or The second needle punch may be a laminate of a porous material to a porous or non-porous material. Nonwoven fibrous materials can be stabilized by bonding or entanglement of the fibers with one another by bonding with various types of chemical bonding, such as hydroentangling, spun bonding, thermal bonding or latex bonding, powder bonding, and the like. . Alternatively, the fibers can be externally bonded to a second sheet material that has at least some mechanical stability. The fibers can be formed from any suitable polymer or other fiber-forming material, such as polypropylene, polyethylene, polyester, nylon, cellulose, superabsorbent fibers or polyamide. Similarly, bi- or multi-component fibers can be used. For example, a polyester core and a polypropylene sheath can be used, which provide relatively high strength for the core material and are easily bonded for the sheath material. Fibers can also be mixed or blended with particles or other fibers of different materials or combinations of materials.
[0017]
The fluid treatment complex can typically be included in disposable garments (eg, disposable diapers and training pants, adult incontinence briefs or sanitary napkin products) where the fluid is discarded. The fluid treatment composite may be bonded to the outer surface or located between a fluid transfer cover layer and a further layer, such as an absorbent layer.
[0018]
The present invention is further described with reference to the accompanying drawings. The same reference numbers in several drawings refer to the same parts.
BEST MODE FOR CARRYING OUT THE INVENTION
[0019]
FIG. 1 is a schematic diagram illustrating a first embodiment of a method and apparatus according to the present invention for making the first embodiment of the fluid treatment complex 11 according to the present invention shown in FIGS. 2 and 3.
[0020]
The method shown in FIG. 1 provides a sheet of porous material 7 on a first rotating corrugated roll 4 forming a plurality of extruded strands 11 with a substantially parallel longitudinal orientation of the molten thermoplastic material. The strands 13 are extruded to provide an arcuate portion 14 projecting in the same direction from the spaced anchor portions 13 of the plurality of strand materials, the strand portions 13 of the strand material projecting from corresponding elongated side surface portions of the porous material 7. Thermal bonding to the porous material by means of an arcuate portion 14 of the existing strand material.
[0021]
As shown in FIG. 1, an apparatus for performing the method comprises a first and a second generally cylindrical column having a plurality of spaced ridges 9 each having an axis and defining a perimeter of corrugated members 4 and 5. With the corrugations 4 and 5 (the ridge 9 has an outer surface and defines a space between the ridges adapted to receive a portion of the ridge 9 of another corrugation in interlocking relationship with the intervening strand material 13). Means for mounting the corrugated member in an interlocking relationship with the portion of the ridge 9 in a direction parallel to the axis, and rotating at least one corrugated member 4 or 5 to supply the strand material 3 between the interlocking portions of the ridge 9. The ridge 9 of the corrugated member 4 or 5 along the outer surface of the ridge 9 of the first corrugated member 4 or 5 so that the strand material is substantially along the periphery of one of the corrugated members 4 or 5. Means for forming an arcuate portion 14 of the strand material in the space between the anchor portions 13 of the strand material and holding a predetermined distance along the perimeter of the corrugated member 4 or 5 after moving past the engagement portion of the ridge 9 And any means (e.g., sandblasting or chemical etching or heating of corrugated members 4 or 5 shaved by heating to a temperature in the range of 25-150 degrees Fahrenheit higher than the temperature of first sheet 12 of flexible material). Extruding the thermoplastic material in the form of an extruder (see FIG. 1) that feeds the die with the variable die plate 2 (including the surface) and stretching in a substantially parallel spaced relationship. Of a plurality of substantially parallel longitudinally extending molten strands 13 and an interval for arranging the molten strands 13 around the corrugated member 4 within a predetermined distance. And means including a stomach opening. Similarly, the apparatus further comprises a supply means such as a roll 10 for supplying a porous material to the nip between the substantially cylindrical bonding roll 6 having an axis and the corrugated member 5 supporting the strand 3, and a corrugated member. Means for rotatably mounting closely spaced bonding rolls 6 in an axis-parallel relationship with 4 and 5 and defining a nip around corrugated member 5 at a predetermined distance from the mating portion of ridge 9; The bonding roll and / or the corrugated roll can be provided with a heating means for assisting in bonding the strand to the porous material 7, and the nip is brought into contact with the cooling roll 24 for cooling and solidifying the strand 16 with the strand 16. For moving the sheet composite 10 for a predetermined distance around the cooling roll 24 passing through the And means, including over La 25.
[0022]
The structure of the sheet composite 10 produced by the method and the apparatus shown in FIG. 1 is shown in FIGS. The fluid treatment composite 11 includes a number of substantially parallel longitudinal strands 3 of thermoplastic material extending in substantially parallel spaced relation. Each of the strands 3 is in the form of a flat cylinder or an ellipse which is closely spaced from the other strands. Strand-spaced anchor sites 13 are thermally bonded to longitudinally-spaced sections of the porous material 7 at first strand bonding locations 12 along a first surface 18 to provide an arcuate portion 14 of the strand material. Project from the first surface 18 of the porous material 7 between the strand bonding locations 12. The first strand bonding 17 locations are spaced at a substantially predetermined distance from each other and are arranged in substantially parallel rows extending across the strands 3 to a predetermined distance from the first surface 18 of the porous material. Form a continuous row of arcuate portions 14 protruding at a first distance. Since the strands 13 have been extruded in the molten form, the anchor sites 13 of the strand material can be pushed around the first surface 18 of the porous material, the ridge 9 of the corrugated member 5 and the bonding roll 6, in which case they still move A thermoplastic polymer strand 16 is formed around the ridge 9 and is jagged. The bond between the strand 3, the anchor site 13 and the porous material 7 at the first strand bonding location extends along the entire strand surface adjacent the ridge 9. As shown in FIG. 4, these portions of the strand surface proximate to the ridge 9 extend along the surface of the jagged anchor portion 13 of the ridge 9 strand 16. Thus, the bonding area between the strand 3 and the porous material is advantageously widened at the strand bonding location to increase the bond level.
[0023]
Another structure that can provide a fluid treatment complex is to space the ridges 9 around the corrugated members 4 and 5 to create a repeating pattern of different spacing between the anchor sites 13 of the strands 3 to form an arcuate shape. Consecutive rows of portions 14 project from the first surface 18 of the porous material 7 at different distances.
[0024]
FIG. 5 shows a second embodiment of the method and apparatus according to the invention for making a second embodiment of the fluid treatment complex 31 according to the invention, which is substantially the same as the fluid treatment complex shown in FIGS. It has the same structure. The method shown in FIG. 5 is somewhat similar to and uses the same devices shown in FIG. Similar parts of the device and product bear the same reference numbers and function the same as the device shown in FIG. In addition to the method steps described above with respect to FIG. 1, the method shown in FIG. 5 includes extruding the strand material 3 directly into the nip formed by the corrugated members 4 and 5. This reduces the distance from the extruder to the bonding roll 6 and reduces or eliminates the need for additional heat to be supplied to the bonding roll 6 and / or corrugated member 5. However, additional heat can, of course, be provided if necessary to increase the bond level above the desired level. The structure of the fluid treatment complex 3 produced by the method and apparatus shown in FIG. 5 is the same as that shown in FIGS.
[0025]
Fluid treatment composite fabrics are primarily used for dewatering high solids content fluid materials at low flow conditions. The product is also disposable, has low weighing of porous media and low denier of filaments or strands of fiber, and enhances bonding capability at low thermal bonding levels. These conditions are often found in personal hygiene products such as incontinence products, baby diapers or menstrual pads. Low flow, high solids content conditions are also possible with fluid filtration such as pool drain filters, medical filters and the like.
[0026]
The porous backing layer is preferably a nonwoven fibrous web formed from thermoplastic fibers such as a bonded carded web, spunlaced fabric, melt blown web, spunbonded web, needle tack nonwoven, and the like. Generally, a porous backing, preferably a nonwoven fibrous web, has a thickness of 10 to 200 g / m2. ^Two , Preferably 20 to 100 g / m ^Two Weighed. At higher weighs, the web becomes more difficult to bond to the corrugated strands and reduces fluid passage. Low weighing makes the web difficult to handle and unstable in end use form. However, additional porous support webs can be used if desired and can be bonded to the porous backing layer.
[0027]
The filaments or strands are extrudable elastic thermoplastic materials such as polyester, polyamide or polyolefin. Polyolefins such as polyethylene and polypropylene polymers (including copolymers or blends) are preferred.
[0028]
The filaments can also be multi-component filaments, such as seed core filaments, wherein the sheath layer has a lower melting or softening point than the core layer material. This can assist in bonding where it is difficult to bond incompatible strand or filament materials. Preferably, the filament is at least partially formed from a polymer having a softening point lower than the softening point of the fibers forming the porous backing layer. A preferred embodiment composite fabric is one in which the filaments are polyolefin fibers and the backing layer is polyolefin.
[0029]
Horizontally orientated thermoplastic filaments are formed by a fibrous backing layer spaced apart from the bonding location along the length of the filament, where the filament forms a compression resistant arc between the bonding locations. Bonded to. The height from the front surface of the arcuate portion of the filament to the backing layer is greater than 0.2 mm and less than 4 mm, preferably 0.5 mm to 3 mm. The diameter of the filament is from 10 mil to 100 mil, preferably from 10 mil to 50 mil. The web must have a compression resistance such that it retains at least 50% of its initial thickness under a load of 1 pound per square inch.
【Example】
[0030]
(Example 1)
A nonwoven filter sheet composite similar to the sheet composite 17 shown in FIG. 2 was produced using the same apparatus as shown in FIG. A thermoplastic ethylene-propylene impact copolymer (8MFI), commercially available under the trade name 7C50 from Union Carbide Corporation of Danbury, Connecticut, is placed in a 51 mm single screw extruder and placed in a filament. 3 was formed. About 4.7 filaments per centimeter of 7C50 copolymer were extruded at 17 RPM from a 0.76 mm orifice onto top corrugated roll 4 at a melt temperature of 238 ° C. The upper corrugated roll was machined to completely place four axis-parallel ridges per centimeter around the roll with a groove between each ridge. Each ridge was machined to provide a top plane approximately 0.7 mm wide. The upper corrugated roll was at about 88 ° C. The partially cooled strand was corrugated at the nip formed by the upper and lower corrugated rolls 5. The lower corrugated roll (113 ° C.) was given the same ridge and groove geometry as the upper corrugated roll by machining to establish a meshing relationship with the upper roll. A line speed of about 7.6 meters per minute and a nip pressure of 100 pounds per linear inch was used. The corrugated strands are 30 grams per square meter of spunbond polypropylene nonwoven fabric 7 (available under the trade designation "RFX" from Amoco Fabrics and Fibers Company of Atlanta, Georgia) of Atlanta, Georgia. Then, bonding was performed at a nip formed by the lower corrugated roll 5 and the smooth metal chill roll 6. The chill roll was maintained at about 150 ° C. The strands were bonded to the nonwoven using a nip pressure of 300 pounds per linear inch. The resulting nonwoven filter sheet composite weighed 58 grams per square meter, and the height of the arcuate strand portion 11 protruding from the nonwoven sheet 13 was about 15 mm. The composite had a compression resistance of 93% as measured as the ratio of the initial thickness to the thickness under a load of 1 pound per square inch.
[Brief description of the drawings]
[0031]
FIG. 1 is a schematic diagram illustrating a first embodiment of a method and apparatus according to the present invention for making a first embodiment of a fluid treatment complex according to the present invention.
FIG. 2 is a perspective view of an embodiment of a fluid treatment complex according to the present invention made by the method and apparatus shown in FIGS.
FIG. 3 is a partially enlarged cross-sectional view taken substantially along a line 3A-3A in FIG. 2;
FIG. 4 is a partially enlarged plan view of FIG. 2;
FIG. 5 is a schematic diagram illustrating a second embodiment of a method and apparatus according to the present invention for making a second embodiment of the fluid treatment complex according to the present invention.

Claims (16)

(A) a porous backing layer;
(B) a plurality of mutually parallel thermoplastic filaments extending in a first direction bonded to the porous backing layer at a distance from a bonding location along a length of the filament;
A composite fabric wherein the filaments form a compression resistant arc between the bonding locations. The composite fabric of claim 1, wherein said porous backing layer is a nonwoven fibrous web formed of thermoplastic fibers. 3. The composite fabric of claim 2, wherein said fibrous backing layer is a bonded carded web. The composite fabric according to claim ² , wherein the basis weight of the nonwoven fibrous web is 10 to 20 g / m2. The composite fabric according to claim ² , wherein the basis weight of the nonwoven fibrous web is 20 to 100 g / m2. 3. The composite fabric of claim 2, wherein the height of the arcuate portion of the filament from the front surface of the backing layer is greater than 0.2 mm. 7. The composite fabric of claim 6, wherein the height of the arcuate portion of the filament from the front surface of the backing layer is less than 4.0 mm. 7. The composite fabric of claim 6, wherein said filament diameter is between 10 and 100 mils. 7. The composite fabric of claim 6, wherein said filament diameter is between 10 and 50 mils. 9. The composite fabric of claim 8, wherein said filament is a homogeneous polymer or polymer blend. 9. The composite fabric of claim 8, wherein said filament is a multi-component filament. The composite fabric according to claim 11, wherein the filament is a sea core filament. 13. The composite fabric of claim 12, wherein the multi-component filament has a sheath layer having a lower melting point or softening point than the core layer material. 9. The composite fabric of claim 8, wherein at least a portion of said filaments are formed from a polymer having a softening point lower than said softening point of said fibers forming said backing layer. 15. The composite fabric of claim 14, wherein said filaments are polyolefin fibers and said backing layer is polyolefin. 9. The composite fabric of claim 8, wherein the filament has a compression resistance such that it retains at least 50% of its initial thickness when loaded at least 1 pound per square inch.