MXPA99004329A - Absorbent articles with controllable fill patterns - Google Patents

Abstract

There is provided an absorbent for personal care products which may be divided into about an equally sized center zone, two intermediate zones and two end zones where the ratio of the amount of liquid stored in the center zone to the amount of liquid stored in at least one of the end zones 30 minutes after an insult is less than 5:1. Such an absorbent may be used in personal care products like diapers, training pants, feminine hygiene products, absorbent underpants, adult incontinence products, and the like.

Description

ABSORBENT ITEMS WITH CONTROLLABLE FILL PATTERNS BACKGROUND OF THE INVENTION Traditional absorbent systems for personal care products store essentially all liquid insults in the crotch region. This results in the crotch region being heavily loaded with liquid by the first insult and can result in an inefficient capacity for a second, third or subsequent insult. This load of the crotch area can cause the product to be pushed out of the user, causing discomfort for the user and creating the possibility of a run-off. The storage of insults in the crotch region also requires that the crotch region be wider than would be possible in a system that stores insults in a different location. A wider crotch area also causes discomfort to the user. In addition, storage in the crotch area does not use the entire product area for storage, resulting in a waste of the absorbent material which is usually scattered throughout the product area. Storage primarily in the crotch area will therefore raise the cost of the product through inefficient use of the materials.

A system in which an insult will be accepted by a personal care product and distributed to the remote areas of the product for storage towards the outside of the crotch area so that the crotch area of the product can be free to accept another insult, It will be preferable to the storage design in the crotch area. In this context, the location of the fluid after an insult is mentioned as the filling pattern. The filling pattern has a relationship with other desirable attributes of the absorbent product such as the runoff levels of the product, the ability to achieve a low runoff with a narrow crotch fit and therefore with comfort for the user, and visual aesthetics, such as It was mentioned above. A remote storage system can maximize the use of the product area, to reduce bagging and allow the production of a personal care product with a more comfortable and narrow crotch area. A more efficient use of the product materials should result in a lower cost for the consumer.

It is therefore an object of this invention to provide a personal care product having an absorbent arrangement which can be filled in a particular order such that the insult is moved to remote storage locations. Such a structure will take a liquid insult from the user and move the liquid to a remote storage location in a predetermined progression and pattern of filling. It is a further object of the invention to provide personal care products with narrow crotch designs as well as personal care product designs with specific liquid storage locations.

SYNTHESIS OF THE INVENTION The objects of this invention are achieved by an absorbent system which includes components that have been designed, arranged, and assembled so that within a certain time after each of the three insults, the liquid will be located in a previously specified area. of the absorbent system. The absorbent system of this invention has a filling ratio of grams of liquid located in the central target zone on either side of the end zones which is less than 5: 1 after each of the three insults. It is preferred that this fill ratio be less than 3: 1 and more preferably be less than 2.5: 1.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view drawing of a cradle used for the MIST evaluation test.

Figure 2 is a side sectional view of a typical personal care product such as a diaper, showing an emergence layer, five retention zones, a distribution layer and a backing sheet.

Figure 3 is a side sectional view of a personal care product such as a diaper as described in Example 1 showing an emergence layer, a multifunctional material, five retention zones, a distribution layer and a backing sheet .

DEFINITIONS The word "disposable" includes discarding after usually a single use and is not intended to be washed and reused.

"Frontal" and "posterior" are used throughout the description to designate relationships with respect to the garment itself, rather than to suggest any position that the garment assumes when it is placed on a wearer.

"Hydrophilic" describes the fibers or surfaces of the fibers which are wetted by the aqueous liquids in contact with the fibers. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular fiber materials can be provided by a Cahn SFA-222 Surface Force Analyzer System, or by an essentially equivalent system. When measured with this system, fibers having contact angles of less than 90 degrees are designated "wettable" or hydrophilic, while fibers having contact angles equal to or greater than 90 degrees are designated "non-humidifying" or hydrophobic.

"Interior" and "exterior" refers to the positions in relation to the center of an absorbent garment, and particularly transversally and / or longitudinally closer or away from the longitudinal and transverse center of the absorbent garment.

"Layer" when used in the singular may have the dual meaning of a single element or a plurality of elements.

"Liquid" means a non-gaseous substance and / or a material that flows and can assume the interior shape of a container into which it is poured or placed.

"Liquid communication" means that liquid such as urine is able to move from one place to another.

"Longitudinal" and "transversal" have their usual meanings. The longitudinal axis lies in the plane of the article when it is placed flat and fully extended and is generally parallel to a vertical plane that divides into two parts a user in the left and right body halves when the article is used. The transverse axis lies in the plane of the article generally perpendicular to the longitudinal axis.

"Particle" refers to any geometric shape such as, but not limited to spherical grains, cylindrical yarns or fibers, or the like.

"Spray" and variations thereof includes a forcibly expelled liquid, either as a stream such as swirling filaments or atomized particles through an orifice, nozzle, or the like, by means of an applied pressure of air or other gas, by the force of gravity, or by centrifugal force. Spraying can be continuous or non-continuous.

The "spunbonded fibers" refer to fibers of small diameter which are formed by extruding a melted thermoplastic material as filaments of a plurality of usually circular and thin capillaries of a spinner with the diameter of the filaments extruded being rapidly reduced as it is said, by way of example, in U.S. Patent No. 4,340,563 issued to Appel et al., and in U.S. Patent No. 3,692,618 issued to Dorschner et al., in the patent of the United States of America. United States of America number 3,802,817 granted to Matsu i and others, in the patents of the United States of America numbers 3,338,992 and 3,341,394 granted to Kinney, in the patent of the United States of America number 3,502,763 granted to Hartman, and in the patent of the United States of America. United States of America number 3, 542,615 granted to Dobo and others. Spunbonded fibers are not generally sticky when they are deposited on the collector surface. Spunbonded fibers are generally continuous and have average diameters (from a sample of at least 10) larger than 7 microns, more particularly, between about 10 and 20 microns. The fibers may also have shapes such as those described in U.S. Patent Nos. 5,277,976 to Hogle et al., In U.S. Patent No. 5,466,410 to Hills and 5,069,970 and 5,057,368 to Largman and others. , which describe fibers with unconventional shapes.

"Meltblown fibers" means fibers formed by extruding a melted thermoplastic material through a plurality of capillary matrix vessels, usually circular and thin like melted threads or filaments into gas streams (eg air), usually hot and high speed and convergent which attenuate the filaments of melted thermoplastic material to reduce its diameter, which can be a microfiber diameter. Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collector surface to form a meltblown fabric of fibers randomly discharged. Such a process is described, for example, in U.S. Patent No. 3,849,241. The meltblown fibers are microfibers which may be continuous or non-continuous, are generally smaller than 10 microns in average diameter, and are generally sticky when deposited on a collecting surface.

As used herein, the term "coform" means a process in which at least one meltblown die head is arranged near a conduit through which other materials are added to the fabric while it is being formed. Such other materials may be pulp, super absorbent particles, natural or synthetic short fibers, for example. The coform processes are shown in commonly assigned US Pat. Nos. 4,818,464 to Lau and 4,100,324 to Anderson et al. Fabrics produced by the coform process are generally mentioned as coform materials.

"Conjugated fibers" refers to fibers which have been formed from at least two polymer sources extruded from separate extruders but spun together to form a fiber. Conjugated fibers are also sometimes referred to as multicomponent or bicomponent fibers. The polymers are usually different from one another even though the conjugated fibers can be monocomponent fibers. The polymers are arranged in different zones placed essentially constant across the cross section of the conjugated fibers and extend continuously along the length of the conjugated fibers. The configuration of such a conjugate fiber can be, for example, a pod / core arrangement where one polymer is surrounded by another or can be a side-by-side arrangement, a cake arrangement or an arrangement of "islands in the sea". . Conjugated fibers are shown in U.S. Patent No. 5,108,820 issued to Kaneko et al., In U.S. Patent No. 5,336,552 issued to Strack et al., And in the U.S. Patent Number 5,382,400 awarded to Pike and others. For the two component fibers, the polymers may be present in proportions of 75/25, 50/50, 25/75 or any other desired proportions. The fibers may also have the forms such as those described in U.S. Patent Nos. 5,277,976 issued to Hogle et al., And 5,069,970 and 5,057,368 issued to Largman et al., Incorporated herein by reference in their entirety, which describe the fibers with unconventional shapes.

The "biconstituent fibers" refer to fibers which have been formed from at least two extruded polymers from the same extruder as a mixture. The term "mixture" is defined below. The biconstituent fibers do not have the various polymer components arranged in different zones placed relatively constant across the cross-sectional area of the fiber and the various polymers are usually not constant along the entire length of the fiber, instead of this they usually form fibrils or protofibrils which start and end in a random way. The biconstituent fibers are sometimes referred to as a multi-constituent fibers. Fibers of this general type are discussed in, for example, U.S. Patent No. 5,108,827 issued to Gessner. Bicomponent and biconstituent fibers are also discussed in the text "Mixtures and Compounds of Polymers" by John A. Manson and Leslie H. Sperling, copyright 1976 by Plenum Press, a division of Plenum Publishing Corporation of New York, IBSN 0 -306-30831-2, pages 273 to 277.

The "bonded carded fabric" refers to fabrics that are made of short fibers which are "sent" through a combing or carding unit, which separates and aligns the short fibers in the machine direction to form a fibrous nonwoven fabric oriented generally in the machine direction Such fibers are usually purchased in bales which are placed in a mixer or picker / opener which separates the fibers before the carding unit. It is joined by one or more of several known methods of bonding, one such bonding method is the binding with powder, wherein the powder adhesive is distributed through the cloth and then activated, usually by heating the adhesive. Fabric and Hot Air Adhesive Another suitable bonding method is a bonding pattern where heated calendering rolls or ultrasonic bonding equipment are used to join the fibers together, usually at n localized bonding pattern, even when the fabric can be bonded through its entire surface if desired. Another suitable and well known joining method, particularly when short conjugated fibers are used, is the bonding via air.

"Air placement" is a known process by which a fibrous nonwoven layer can be formed. In the air laying process, bunches of small fibers having typical lengths ranging from about 3 to 19 millimeters (mm) are separated and carried in an air supply and then deposited on a forming grid, usually with the help of a vacuum supply. The randomly deposited fibers are then bonded together using, for example, hot air or sprayed adhesive.

"Personal care product" means diapers, training pants, absorbent pants, incontinence products for adults and feminine hygiene products.

TEST METHODS Absorption Time Index (ATI): In this test the absorbent capacity of a super absorbent material is determined against time by up to 200 minutes under light pressure, for example around 0.01 psi.

A cylinder of 25.4 millimeters in internal diameter with a 100-mesh stainless steel grid on one end is used to retain 0.16 ± 0.005 grams of dry super absorbent. The super absorbent should be placed carefully in the cylinder so that the super absorbent does not stick to the sides of the cylinder. The cylinder should be bled gently to evenly distribute the super absorbent over the grid. A 0.995 diameter plastic piston of 4.4 grams is then placed in the cylinder and the cylinder, piston and super absorbent assembly are weighed.

The assembly is placed in a 76.4 millimeter by 76.4 millimeter fluid container having a salt water solution of 0.875 weight percent NaCl at a depth of 1 centimeter. Lightly tap the cylinder to remove any air trapped under it and maintain the depth of the salt water solution at 1 centimeter through the test.

Use a stopwatch capable of reading 200 minutes at 1 second intervals. Start the measurement of time and after 5 minutes in the solution, remove the assembly and dry on absorbent paper. A favorite role is that of napkins Kleenex® Premium from Kimberly-Clark Corporation even when any other effective paper can be used. When drying, press the paper tightly against the cylinder to ensure good contact. Touch the cylinder three times with dry paper and there should be very little liquid removed the third time.

Weigh the assembly and return the assembly to the fluid container. Drying and weighing should take about 5 seconds and the time meter should keep running through the test. Take readings at 5, 10, 15, 30, 45, 60, 75, 90, 120, 160 and 200 minutes. Use fresh dry napkins for each reading.

After the final reading calculate the grams of fluid absorbed per gram of super absorbent. The amount of liquid absorbed at particular times divided by the amount absorbed at 200 minutes can be plotted against time for a graphical representation of the absorption rate.

The ATI is calculated as follows: ATI = (t10 + t2o + t30 + t40 + t50 + t60 + t70 + tg0 + t90) / 9 where tn is the time in minutes in which n percentage of the absorbent capacity at 200 minutes is used, for example t ^ is the time at which 30 percent of the total capacity is used.

Multiple Insult Test (MIST Evaluation): In this test a fabric, material or structure composed of 2 or more materials is placed in an acrylic crib to simulate the curvature of a user's body such as an infant. Such a cradle is illustrated in Figure 1. The cradle has a width within the page of the drawing as shown of 33 centimeters and the ends are blocked, a height of 19 centimeters, an internal distance between the upper arms of 30.5 centimeters and a angle between the upper arms of 60 degrees. The crib has a 6.5-millimeter wide slot at the lowest point running at the length of the crib inside the page.

The material to be tested is placed on a piece of polyethylene film of the same size and shape as the sample and placed in the cradle. The material to be tested is insulted with 80 milliliters of saltwater solution of 8.5 grams of sodium chloride per liter, at a rate of 15 cc / sec with a normal nozzle at the center of the material and 1/4 of an inch ( 6.4 mm) above the material. The nozzle orifice is circular in shape with a diameter of 2.72 millimeters. The amount of spill is recorded. A charge of 0.1 psi is placed on the material while it is still in the cradle using, for example, an air bladder. After 30 minutes the fluid distribution was determined either by an X-ray imaging procedure (a non-destructive test) or by the cutting and weighing procedure (a destructive test). If a non-destructive test is carried out, after the liquid distribution is determined the material is placed back in the cradle in the same orientation as before and the liquid and insult determination procedure is repeated. The insult and the determination of liquid distribution are usually repeated for a total of three times. After the final insult, it can be used if destructive testing is desired.

X-ray Image Test: This test was a method used to determine the amount of fluid in each of the five zones of the absorbent systems. The X-ray image is known in the art as discussed, for example, in the article entitled "Fluid Distribution: Comparison of X-ray Image Data" by David F. Ring, Oscar Lijap Joseph Passed in the magazine "Mundos of the Non Woven ", will see from 1995, pages 65-70. Generally, this procedure compares the X-ray images of a wet and dry sample in order to calculate the liquid content. Such lightning systems are available from Tronix Inc. of 31 Business Park Drive, Branford, CT 06045 as model number 10561 HF 100 with annex. This system uses a computer program from Optumus Inc., d. Forth Collins, CO as Bio-scan Optimate® S / N OPM4101105461 version 4.11. The X-ray system was operated with an exposure time of 2 seconds, with a tube voltage of 50 Kv and a current of 12 mA.

Capillary Tension: The capillary tension (ct) expressed in centimeters (cm) of liquid was calculated from the characteristics of the fiber and the fabric by equating the capillary pressure exerted by the material with the hydrostatic pressure provided by a column of liquid per u method known in the art and taught in a number of references, for example "Textile Science and Technology", volume 7, by Pronoy K. Chatterjee, published by Elsevier Science Publishers B.V. 1985, ISBN 0-444-42377-X (volume 7), chapters 2, 4 and 5. These calculations assume a surface tension of 68 dynes / cm that is taken from a saline solution of 8.5 gm / 1 used as an approximation or simulation of urine. Urine can be very variable in surface tension.

The capillary tension can be computed or determined experimentally by the vertical transmission height test described here. The computations are used in the presence of test liquids, especially materials containing super absorbent when exposed to salt water.

Variable Dimensions c.t. = 2 -X to cm salt water cm2 / g paste For. P.10 and 11 g / cm3 g / cm3 cm for long cylinders for spheres where = fluid surface tension (dyne / cm)?, - liquid-solid contact angle in advance (degrees) for the component i TT = 3.1415906 Pteia = fabric density (g / cm3) Average = density of average mass heavy component. { g / cm3) di = component diameter (miera) Pi = component density (g / cm3) Xi = fraction of mass of component i in fabric ri, effec = effective fiber radius (cm) B = weight of sample / area (g / m2) t = sample thickness (mm) under 0.05 psi (23.9 dyne / cm2) or 2.39 Pascal (N / m2) load L = cylinder length (cm) V¡ = volume of component i ( cm3) SAj = surface area of component i (cm2) Calculation of Example of Capillary Tension For a structure which contains 57 percent southern softwood pulp, 40 percent super absorbent and 3 percent binder fiber, and has a basis weight of 617.58 g / m2 and a volume thickness of 5.97 mm at 0.05 psi, the example calculation of saltwater capillary tension follows.

The properties of the component are as follows: Note that the shape and contact angles are approximate Variable ex (cm2 / g) to (cm2 / g) paste For. p. 12 a (cm2 / g) Pprom (g / cm3) Pprom (g / cm3) Pprom (g / cm3) Pteta (g / cm3) Pteia (g / cm3) P. F. P. 12 Pteía (g / cm3) c.t. (cm salt water) c.t. (cm salt water) c.t. (cm salt water) Permeability: The permeability (k) can be calculated from the Kozeny-Carman equation. This is a widely used method. References include an article by R.W. Hoyland and R. Field in the newspaper "Technology and Paper Industry" December 1976, pages 291-299 and "Pore Structure and Transport of Medium Porous Fluid" by F.A.L. Dullien, 1979, Academic Press, Inc. ISBN 0-12-223650-5.

Calculated Variable Equation Dimensions Permeability = k You will give Constant Kozeny = K -. Without dimension Surface Area per material mass = Sv cm2 / g Average heavy mass component density = Pprom g / cm3 Surface area by = S0 cm solid volume of material Porosity Without Dimension Fiber effective radius = ri efec cm Fabric density = Pteia g / cm3 For long effec cylinders For spheres "defec Where di = diameter of component i (microns) Pj = density of component i (g / cm3) Xi = fraction of mass of component i in fabric BW = weight of sample / area (g / m2) t = thickness of sample (mm) under 0.05 psi (23.9 dyne / cm2) or 2.39 Pascal (N / m2) load Calculation of Permeability Example For a structure which contains 57 percent southern softwood pulp, 40 percent super absorbent and 3 percent binder fiber, and has a basis weight of 617.58 g / m2 and a volume thickness of 5.97 mm at 0.05 psi, follow the example permeability calculation.

The properties of the component are as follows (note that the form is approximate) Pteía (g / cm3) Pteía (g / cm3) P. p. 14 Pteía (g / cm3) = 0. 1034 = 1? Xj Ptela 0. 9309 Sv (cm2 / g) p.p.15 10 Sv (cm2 / g) Sv (cm2 / g) = 1194 Pprome (g / cm3) Pprom (g / cm3) Pprom (g / cm3) 20 (cm-1) = Sy Ppro S0 (c 1) = 1194 x 1,496 S0 (cm "1) = 1786 K K K = 10.94 p.p.15 p.p.16 491 darcis Material Calibration (Thickness) The material gauge, which is a measure of thickness, is measured at 0.05 psi with a Starret-type volume tester, in units of centimeters.

Density. The density of the materials is calculated by dividing the weight, by unit area of a sample in grams per square meter (gsm) by the volume of the sample in millimeters (mm) to 68.9 Pascals and multiplying the result by 0.001 to convert the value in grams per cubic centimeter (g / cc). A total of three samples will be evaluated and averaged for the density values.

Transmission Time and Vertical Liquid Flow of an Absorbent Structure. A sample strip of approximately 5 centimeters by 38 centimeters material was placed vertically so that when the sample strip was placed on top of a liquid reservoir at the beginning of the test, the bottom of the sample strip will just touch the surface of the sample. liquid. The liquid used was a salt water solution of 8.5 g / 1. The relative humidity should be maintained at around 90 to about 98 percent during the evaluation. The sample strip was placed above the known weight and liquid volume and timing was started as soon as the bottom edge of the sample strip touched the surface of the solution.

The vertical distance of the liquid front was recorded by moving upwards of the sample strip and the liquid weight absorbed by the sample strip at various times. The time plot was drawn against the liquid front height to determine the transmission time to around 5 centimeters and to around 15 centimeters. The weight of the liquid absorbed by the sample strip from the beginning of the evaluation to around 5 centimeters and to around 15 centimeters in height was also determined from the data. The value of the vertical liquid flow of the sample strip at a particular height was calculated by dividing the grams of liquid absorbed by the sample strip by each of: the basis weight (gsm) of the sample strip; the time, in minutes, necessary for the liquid to reach the particular height; and the width, inches, of the sample strip. The equilibrium capillary tension is considered to be the height of the liquid at the end of 30 minutes.

DETAILED DESCRIPTION The objects of this invention are achieved by an absorbent system which includes components that have been designed, arranged and assembled so that within a certain time after each insult, the liquid is located in a previously specified area of the absorbent system. Such an absorbent system should not retain the volume of insult in the crotch area. This will allow the production of articles that conform more to the body and narrower crotch area and this will result in a better fit and greater user comfort, and a more efficient use of materials. When referring to diapers and training shorts, a narrow crotch is one of a width which is at most 7.6 centimeters wide, more particularly, at most 5 centimeters wide.

The fill pattern refers to the preferentially designed location of the liquid in specific zones or parts of the zones along the length of a product. Specific filling patterns include, but are not limited to, liquid stored uniformly throughout the product, liquid stored completely on the front of the product, liquid stored completely on the back of the product, and liquid stored uniformly throughout the product except for an area essentially free of liquid somewhere in the product. If a liquid-free area is provided, it may extend over a complete area or may extend over part of one or more zones and be in various forms such as circles, ovals, etc. The presence of the essentially liquid-free zone can be used for some other additional functional purpose such as to create a region of improved dryness, a superior air circulation and / or a hollow area for BM storage. The location of the area essentially free of liquid, it can be anywhere in the absorbent product. The substantially liquid-free zone may be located in the target crotch area area, for example, to increase air circulation to help reduce the occurrence of genital inflammation. The essentially liquid-free zone may be located in an intermediate zone in order, for example, to allow a space for BM storage. There may be more than one liquid-free area in a personal care product.

Each filling pattern also has an associated filling progression and even though the filling pattern and filling progression may be the same, the invention is not limited to them as being the same. For example, an absorbent system product may have a front fill pattern in the first insult, and a "back fill pattern" in the second insult, and a bottom fill pattern in the third insult. of such a system, the general filling pattern is uniform, but the filling progression is front, back and bottom.As another example, for the specific modality that has a uniform filling pattern, the absorbent system not only has liquid uniformity distributed at the end of the life of the product (which is simulated by three insults), but has the liquid essentially evenly distributed after the first and second insults.A similar example includes modalities which have a frontal filling pattern. If the modality has a frontal filling pattern after each insult, then it also has a frontal filling progression.This invention includes both pat variations. controlled filling and fill progression and demonstrates examples of achieving both.

It is useful for the purpose of the discussion and for ease of understanding to divide the absorbent system into zones along its length and discuss the filling pattern in terms of fluid located in each zone at the end after some time after each insult. The absorbent systems discussed here have been divided transversely into five zones for clarity, but it should be noted that they are not necessarily zoned into compositions or the manufacturing process or that they are physically separated in any way. The zones are purely for ease of understanding and illustration of the location of the liquid in the absorbent system of a personal care product. Along the length of the product, the cross-sections are arbitrarily defined and divided to be approximately equal to one fifth of the overall product length, or, in the examples, about 7.6 centimeters each. Figure 2 shows a side view of an absorbent system having five such numbered areas 1-5 from the front of the article to the back; the central target area 3, two end retention zones (front and back), 1, 5 respectively and two intermediate zones (front and back), 2 and 4 respectively. The central objective area 3, if the absorbent system were part of a hygiene product for women or for personal care, would generally be located in the position where an insult will be delivered by a user. The absorbent article of Figure 2 also includes an emergence material 6, a distribution material 7 and a backing sheet 8.

In the Examples, the width of each zone is three inches in the Examples of rectangular absorbent system. The width of the zone is variable in the shaped absorbent systems. This invention applies to both shaped and rectangular absorbent system products, and even when the specified number of zones, 5, is for illustrative purposes only, more or fewer zones may be included for different illustrations of the invention.

We define a proportion of grams of fluid located in the central target zone 3 for each of the end retention zones 1, 5 as the fill ratio. The fill ratio is calculated by dividing the grams of fluid in zone 3 or the grams of fluid in each of the end retention zones 1, 5 after the specified time. In order to fall within the scope of this invention, this filling ratio of center: end is less than 5: 1 after a first insult, after a second insult and after each of the three insults, at least one end zone. It is preferred that the center fill: end ratio be less than 3: 1, and more preferably be 2.5: 1. It should be noted that even when the test for determining center-end zone proportions uses a vertically oriented absorbent system here, the invention is independent of the position in which the system is tested, for example an absorbent system inclined or oriented to a side should provide the same results.The grams of fluid in a zone can be determined simply by cutting the absorbent system into approximately equally dimensioned pieces corresponding to the zones, weighing each zone and comparing each wet area weight with a known dry weight. The division of fluid in each zone can also be determined by the X-ray procedure given in the test methods section.

The absorbent systems that fill the fill ratio requirement move a substantial part of the liquid out of the target area and benefit the product by preparing it for multiple insults. Another result of such low fill ratio absorbent systems is lower and subsequent insult leakage values than absorbent systems that preferably retain the liquid in the target zone. Systems that preferably retain the liquid in the target zone are referred to herein as high fill ratio systems and also have second and third insult spill values superior to those of the low fill ratio absorbent systems. The potential runoff levels are predicted by the liquid runoff values of the controlled banking tests. Absorbent systems within the scope of this invention should have less than 40 ml of the total spill of three 80 ml insults (240 ml total insult volume) delivered at a rate of 15 ml / sec at 30 minute intervals. This feature of functional realization must be achieved with an absorbent system product having a fully saturated capacity of less than 450 grams.

The traditional absorbent systems for personal care products can be generalized as having the functions of control and containment of emergence (retention) or SC.

Emergence control materials, the "S" in SC, are provided to quickly accept the incoming insult and either absorb, retain, channel or otherwise handle the liquid so that it does not run out of the article. The emergence layer can also be referred to as a take-up layer, a transfer layer, a transport layer and the like. An emergence material typically must be capable of handling an incoming insult of between about 60 and 100 cc at a volumetric flow rate of from < around 5 to 20 cc / sec for infants, for example. The emergence control is typically provided by a fluff pulp in an absorbent product or by a non-woven layer of high permeability.

The containment or retention materials, the "C" in SC, they must absorb the insult quickly and efficiently. These must be able to absorb the liquid without a significant "gel block" or a blockage of liquid penetration beyond the absorbent by the expansion of the outer layers of absorbent. The retention materials are frequently compounds containing high-absorbency super-high-density polymers such as mixtures of polyacrylate super absorbent and fluff. These materials absorb and quickly retain the liquid.

In addition to the control and containment materials of emergence in traditional absorbent systems, recent work has introduced another layer interposed between layers S and C. This new layer is a distribution layer, producing a system with an emergence control , distribution and containment or "SDC". While it seems obvious, it should be noted that in order to function effectively, the materials used in this invention must have sufficient contact to transfer the liquid therebetween.

The distribution materials, the "D" in SDC, must be able to move the fluid from the initial deposit point to where storage is desired. The distribution must take place at an acceptable rate so that the target insult area, usually the crotch area, is ready for the next insult. By "ready for the next insult" is meant that enough liquid has been moved out of the target area so that the next insult results in the absorption and discharge of the liquid within acceptable volumes. The time between insults can vary from just a few minutes to hours, generally depending on the age of the user. It should be noted that the simple addition of a dispensing material to current absorbent systems is not sufficient to achieve the benefits of the present invention. Such a system can cause some liquid to move to remote areas but this movement is limited in volume especially when working against a negative hydrostatic head caused, for example, by a difference in height between the target and remote area areas . Such a system will result in a preferential filling of the capacity of the target area before substantial movement of the liquid to the remote storage areas takes place.

Absorbent products such as, for example, diapers, generally have a liner which is against the wearer, a back sheet which is the outermost layer and may also contain other layers such as the multifunctional materials described in the application No. 08/754, 414 filed the same day and assigned to the same assignee as this application and entitled MULTIFUNCTIONAL ABSORBENT MATERIALS AND PRODUCTS MADE OF THEM.

The lining is sometimes referred to as a side-to-body lining or top sheet and is on one side of the emergence material. In the thickness direction of the article, the lining material is the layer against the user's skin and thus the first layer in contact with the liquid or other exudate of the wearer. The lining also serves to isolate the user's skin from liquids maintained in the absorbent structure and must be flexible, soft feeling and non-irritating.

Various materials can be used to form the side-to-body liner of the present invention, including perforated plastic films, woven fabrics, non-woven fabrics, porous foams, cross-linked foams and the like. Non-woven materials have been found to be particularly suitable for use in the formation of the side-to-body liner, including spin-bonded or melt-blown fabrics of polyolefin filaments, polyester, polyamide (or other fiber-forming polymer) similar, or carded and bonded fabrics of natural polymers (e.g., rayon or cotton fibers) and / or synthetic polymer fibers (e.g., polypropylene or polyester). For example, the side-to-body liner may be a fabric bonded by non-woven yarn of synthetic polypropylene filaments. The nonwoven fabric may have a basis weight for example, ranging from 10.0 grams per square meter (gsm) to about 68.0 gsm and more particularly from about 14.0 gsm to about 42.0 gsm, a volume or thickness varying from about 0.13 millimeters (mm) to about 1.0 mm, and more particularly from about 0.18 mm to about 0.55 mm, and a density of between about 0.025 grams per cubic centimeter (g / cc) and about 0.12 g. / cc, and more particularly between about 0.068 g / cc and about 0.083 g / cc. Additionally, the permeability of such non-woven fabric can be from about 150 Darcy to about 5000 Darcy. The non-woven fabric can be treated on the surface with a selected amount of surfactant, such as about 0.28% Triton X-102 surfactant or otherwise processed to impart the desired level of wettability and hydrophilicity. If a surfactant is used, it can be an internal additive or applied to the fabric through any conventional means, such as spraying, printing, embedding, brush coating and the like.

The emergence layer is more typically interposed between and in an intimate liquid communication contact with the body-side liner and another layer such as a distribution or retention layer, or the multifunctional material of the co-pending application entitled MULTIFUNCTIONAL ABSORBENT MATERIALS. AND PRODUCTS MADE OF THEM.

The emergence layer is generally underlying the internal (unexposed) surface of the liner from side to body. To further improve the transfer of the liquid, it may be desirable to hold the upper and / or lower surface of the emergence layer to the liner and distribution layer, respectively. Suitable conventional clamping techniques can be used, including without limitation, bonding with adhesive (using water-based, solvent-based and thermally activated adhesives) thermal bonding, ultrasonic bonding, sewing and bolting, as well as combinations of the above or other appropriate fastening methods. If, for example, the emergence layer is adhesively bonded to the liner from side to body, the amount of adhesive added must be sufficient to provide the desired level or levels of bonding, without unduly restricting the flow of liquid from the liner to the liner. emergence layer. An example emergence material can be found in the United States patent application of North America No. 08/755, 514 filed the same day and assigned to the same transferee as this application is entitled HIGHLY EFFICIENT SURFING MATERIAL FOR ABSORBENT ITEMS, which presents a surfacing material which is a wettable fiber fabric of at most of 30 microns in diameter where the fabric has a permeability of between about 250 and 1500 Darcys, a capillary tension between about 1.5 and 5 cm, and which maintains that permeability and capillary tension during the life of the fabric. It is preferred that the fabric has a density of between about 0.02 g / cc to about 0.07 g / cc. Various woven fabrics and non-woven fabrics can be used to construct an emergence layer. For example, the emergence layer may be a layer of non-woven fabric composed of a fabric joined by spinning or melt blowing of polyolefin filaments. Such non-woven fabric layers may include conjugate biconstituent and homopolymer fibers of short or other lengths and blends of such fibers with other types of fibers. The emergence layer can also be a bonded carded fabric or an air-laid fabric composed of natural and / or synthetic fibers. The bonded carded fabric can, for example, be a powder-bonded carded fabric, an infrared-bonded carded fabric or a carded fabric bonded through air. The carded fabrics may optionally include a mixture or combination of different fibers, and the fiber lengths within a selected fabric may vary from about 3 mm to about 60 mm.

The distribution layer must be able to move the fluid from the initial deposit point to where storage is desired. The distribution must take place at an acceptable rate so that the target insult area, usually the crotch area, is ready for the next insult. The time between insults can vary from just a few minutes to hours, generally depending on the age of the user. In order to achieve this transport function, a distribution layer must have a high capillary tension value. The capillary tension in the distribution materials is measured simply by the equilibrium transmission of a saltwater solution of 8.5 g / 1 according to the vertical liquid flow rate test, not by the test method given for the materials containing super absorbent. A successful distribution layer must have a capillary tension greater than the adjacent layer (on the side towards the user) and preferably a capillary tension of equilibrium transmission height of at least about 15 centimeters. Due to the generally inverse relationship between capillary tension and permeability, such high capillary tension indicates that the distribution layer will usually have a low permeability.

Another desired liquid transport property of a suitable distribution material is that it exhibits a vertical liquid flow rate at a height of about 15 cm, suitably at least about 0.002 grams of liquid per minute per square meter. (gsm) of the distribution material per inch width in cross section of the distribution material g / (min * gsm * inch) to about 0.1 g / (min * gsm * inch). As used herein, the Vertical Liquid Flow Rate value of a distribution material is intended to represent the amount of liquid transported through a limit at a specified vertical distance outward from the insult location of the centralized liquid per minute. by standardized amount of distribution material. The vertical liquid flow rate, at a height of about 15 centimeters, of a distribution can be measured according to the test method described here.

Another property of liquid transport of a distribution material is that it exhibits a vertical liquid flow rate at a height of about 5 centimeters, suitably at least about 0.01 g (min * gsm / inch). up to about 0.5 g / (min * gsm * inch). The vertical liquid flow rate, at a height of about 5 centimeters, of an absorbent structure can be measured according to the test method described here.

The tparerials from which the distribution layer can be made include woven fabrics and non-woven fabrics, spurs and filamentary materials. For example, the distribution layer may be a nonwoven fabric layer composed of a meltblown fabric bonded by spinning polyolefin filaments, polyester, polyamide (or other fabric forming polymer). Such nonwoven fabric layers may include bicopstituent and homopolymer fibers of short conjugated or other lengths and blends of such fibers with other types of fibers. The distribution layer can also be a carded and bonded fabric, air laid fabric or a wet laid pulp structure composed of natural and / or synthetic fibers, or a combination thereof.

As previously described in the previously owned and previously cited patent application of MULTIFUNCTIONAL ABSORBENT MATERIALS AND PRODUCTS MADE WITH THEM, the multifunctional material has been designed to assist the emergence material 1) by accepting a part of the volume of insult during the forced flow, for example, during the actual insult, 2) by desorbing the material arising from liquid during and after insults, 3) by allowing a part of the insult volume to pass through itself (the multifunctional material up to the distribution material and 4) by permanently absorbing a part of the liquid insult. The basic structure of the multifunctional material is a unique blend of super-absorbent material, high-volume wet elastic pulp, and a structure-stabilizing component such as a binder which can be a fiber, a liquid or other binder means. Exemplary binders include conjugated fibers of polyolefins and / or polyamides, of homopolymer microfibers such as polypropylene fibers blown by melting into a coform with the other ingredients for entangling and / or bonding, and liquid adhesives. The multifunctional material has a permeability of between about 100 and 10,000 Darcys, a capillary tension between about 2 and 15 cm and a running rate of less than 25 ml per 100 ml of insult during its lifetime. The "life" of the multifunctional material is considered as being three insults of 100 ml each where each insult is separated by 30 minutes. In order to achieve the required capillary tension and permeability, it is preferred that the multifunctional material have between 30 and 75 percent by weight of the super absorbent of slow rate, between 25 and 70 percent by weight of pulp and of a positive amount up to 10 percent - of a binder component. The material should have a density between about 0.05 and 0.5 g / cc. The base weight of the material will vary depending on the application of the product but it should generally be between about 200 and 700 gsm. By "super slow" super absorbent what is meant is a super absorbent having an absorption time index (ATI) of at least 5 minutes and preferably more than 10 minutes.

The backing sheet is sometimes referred to as the outer cover and is the layer furthest away from the user. The outer cover is typically formed of a thin thermoplastic film, such as a polyethylene film, which is essentially impermeable to liquid. The outer cover works to prevent the exudates of the body contained in an absorbent structure from wetting or soiling the wearer's clothing, bedding or other materials that make contact with the diaper. The outer cover can be, for example, a polyethylene film having an initial thickness of from about 0.5 mil (0.012 millimeters) to about 5.0 mil (0.12 millimeters). The outer cover of polymer film may be etched and / or may be matte finished to provide a more aesthetically pleasing appearance. Other alternate constructions for the outer shell include woven or nonwoven fibrous webs that have been constructed or treated to impart the desired level of liquid impermeability., or laminates formed of a woven or non-woven fabric and thermoplastic film. The outer cover can optionally be composed of a "breathable" microporous material, permeable to steam or gas, which is permeable to vapors or gas but essentially impermeable to liquid. The breathability can be imparted to polymer films by, for example, the use of fillers in the film polymer formula, extruding the filler / polymer formula into a film and then stretching the film sufficiently to create voids around the particles of filling, making the film breathable. Generally, the more filling is used and the higher the degree of stretching, the greater the degree of breathability. The backrests can also serve the function of a member that matches for mechanical fasteners, in the case, where a non-woven fabric is the outer surface.The retention materials used in this invention must absorb the liquid from the distribution layer in a controlled manner so that the liquid can be stored in the desired pattern. Suitable retention materials for this application should contain an absorbent composition comprising from 20 to 85 percent by weight of the super absorbent, from 80 to 0 percent by weight of pulp from a positive amount to about 10 percent by weight. weight of a binder component and which has a density between about 0.1 and 0.4 g / cc. The retention materials must, of course, be mechanically stable in order to survive dry and wet conditions of use. The integrity of the retention materials must be provided by small amounts of thermally activated conjugated binder fiber, for example, or by any other suitable means such as, with liquid adhesives, heat activated film adhesives or melted blown fibers which They agglutinate the other ingredients mechanically (by means of entanglement) or adhesively. An example of suitable retention materials can be found in the United States patent of Jackson et al. No. 5,350,370 commonly assigned.

In the examples that follow the emergence material that was used was 90 percent by weight of 3 denier PE / PET conjugate sheath / core fibers with the durable wettable nature in this fabric being supplied by a cellulose (1.5 denier rayon). ) present at 10% by weight. A fabric very similar to this fabric is described in the co-pending patent application entitled HIGHLY EFFICIENT SURFING MATERIAL FOR ABSORBENT ARTICLES, where this is Example 1. .- • - -Í'- .. ••, '. • - .. «--- Ei émplo -1 - '- Example 1 is a layered absorbent system with specific components designed to provide necessary functions as well as a specific array of components to provide designed feature interactions. Example 1 illustrates a modality in which the fluid is distributed and deposited in all five zones at the end of each of the insult cycles, for example, after 30 minutes of the insult. This Example 1 shows the uniform filling progression for a uniform filling pattern.

The functions that the materials and the system must exhibit are the taking (emergence), controlled release, distribution, transfer and final storage. The movement of the liquid in and through the system is controlled by a capillary balance from one material in relation to the other through the life cycle of the system.

The emergence material is a non-woven fabric with a capillary tension capacity of 1.5 cm - 5 cm, with a permeability range capacity of 250-1500 Darcys. The emergence material used in these examples is a 3 inch (7.6 cm) by 5 inch (12.6 cm) carded and bonded fabric consisting of 90% BASF 1053 polyethylene / polyethylene terephthalate (PE / PET) conjugate of 3 denier mixed with 10 percent by weight of rayon fiber Courtaulds from 1.5 denier to 400 grams and a density of 0.028 g / cc. BASF fibers are available from BASF fibers, 6805 Morrison Boulevard, Charlotte, North Carolina, 28211-3577 and were polyethylene / polyethylene terephthalate (PE / PET) sheath / core conjugated fibers with a C S-2 based in polyethylene glycol. The rayon fibers were Merge 18453 1.5 denier fibers from Courtaulds Fibers Incorporated of Axis, Alabama.

As illustrated in Figure 3, the emergence material 9 is in fluid communication with a multifunctional material 10 which is also in the crotch region and provides some additional take-up capability. This also provides a storage for the temporary liquid, as well as the release to the underlying distribution material 11, and a permanent storage of some fluid. The multifunctional material 10 must have and maintain a level of surface tension above the capillary tension level of the emergence material 9 in order to desorb it. Similarly, it has to have a capillary tension level below that of the distribution material 11 in order to release it. In this example, the required level of capillarity is achieved and maintained with a functional material consisting of a 40 percent by weight mixture of slow super absorbent which was AFA-94-21-5 from The Dow Chemical Company, of Midland MI, 57 per percent by weight of Weyerhaeuser's HBAFF pulp and 3 percent by weight of PE / PP Danaklon binder. Additionally, the permeability range for multifunctional materials is from 100 to 10000 Darcys. In addition, the slow super absorbent component within the multifunctional material 10 stores only a portion of the liquid in the crotch region. The remaining liquid can be released to the distribution material 11 for movement to remote locations and storage at said remote locations out of the crotch area.

The dispensing material 11 is the component that carries the liquid out of the multifunctional material 10 and delivers it and transfers it to the remote storage areas. As shown in FIG. 3, these storage areas are the central area 14, the intermediate front zone 13, the front end area 12, the rear intermediate zone 15 and the rear end area 16. In figure 3 it is also provided the backing sheet 17. The distribution material 11 has to have a capillary tension level above that of the multifunctional material 10 in order to desorb it. The distribution material 11 also has to have sufficient capillary tension capacity to bring the liquid up to 15 cm-25 cm in vertical height in order to feed both intermediate retaining zones 13 and 15 and the end retaining zones 12 and 16. When the user of the product is in a vertical position, vertical strips of between 15 and 25 cm are common for the end zone.

The distribution material in these examples consists of two layers of 100 gsm of chemically stiffened north softwood pulp placed in wet form at a density of about 0.17 g / cc, and a 68 gsm layer of a mixture of 50: 50 by weight of Buckeye HP2 pulp and Kimberly-Clark 1654 pulp at about a density of 0.17 g / cc. The three layers of distribution material were folded together while the 68 gsm layer was adhesively attached to the retention zones and the multifunctional material.

In the examples, the retention material in the intermediate retention zones and the retention material in the end retention areas represent absorbent compounds with a progressively greater capillarity from the target zone. This provides a progressively greater desorption of the distribution material, so that the intermediate retention zone material and the end retention zone material will be filled according to the specific design criteria for the absorbent system.

The filling approach can be adjusted by the distribution of the material flow and the liquid transfer level as well as the absorption rate of the absorbent compounds in the intermediate and end retention zones. In terms of composition, these zones contain 60 percent by weight of super absorbent particulate, such as Stockhausen Favor 870 and 40 percent by weight of cellulose pulp from a softwood class such as Coosa Mills CR-1654 from Kimberly-Clark. Corporation. The retention material in the intermediate retention zones was cold compressed to a density of 0.2 g / cc. The retention material in the end retention areas was treated with 20 percent by weight of an aqueous solution of 1% Kymene and then hot pressed to a density of 0.2 g / cc. The retention material in the intermediate and end zones was adhesively attached to the upper layer of the distribution material 11 in the positions shown in Figure 3. The composition of the five retention zones in this Example 1 is shown in Table 2 .

Absorbent components stabilized with Kymers 557LX were prepared as follows: A predetermined amount of super absorbent and foamed fiber was mixed and formed by air in a sheet structure using a hand-held sheet former, for example a basis weight of between about 100 and 250 gsm. Sufficient layers of the sheet structures were prepared to achieve the desired composite basis weight per layer. Each layer was sprayed with about 10 percent by weight of an aqueous solution containing 0.24 percent by weight of Kymene. The strata were layered after spraying and compressed immediately to the desired density while they were set to 110 ° C. The heating can be carried out in, for example, a heated sculpting press. - "~ Example 2 Example 2 represents an embodiment of the invention that effectively moves the liquid out of the target zone during each insult of the liquid, but preferably filled from the bottom like current commercial filling products. Example 2 uses the same emergence and distribution material used in Example 1. The composition of the retention material is similar in all five zones for this Example 2, consisting of 60 percent by weight particulate super absorbent Favor 870 Stockhausen with 40 percent by weight of pulp fiber which was Coosa CR 1654 from Kimberly-Clark Corporation. Table 2 shows the retention materials for Example 2.

Example 3 Example 3 shows a novel aspect of liquid placement control where an essentially liquid-free zone is created within the absorbent product. The presence of a substantially liquid-free zone can be used for some other additional functional purpose such as creating an improved dry region, a higher air circulation or a hollow area for BM storage. The location of the zone, essentially free-of liquid. Can be anywhere in the absorbent product.

In Example 3, the essentially liquid-free zone is located in the rear intermediate zone position. The posterior intermediate zone was selected to demonstrate the ability of the current invention to control the placement of the liquid on both sides of the essentially liquid-free zone. Example 3 was also designed to give a uniform filling progression and a final fill pattern in the four remaining zones. In this example, the material distribution was continuous through the posterior intermediate zone essentially free of liquid which resulted in the liquid being present in a limited form within the posterior intermediate zone. Alternatively, the distribution material can be placed on one or more sides of the essentially liquid-free zone, or the distribution material can be completely isolated from the essentially liquid-free zone by a localized barrier such as a film, a breathable film or a melt-blown barrier fabric.

The emergence material, the distribution material and the multifunctional material described in the Example 1 are the same for Example 3. The composition of the retention material in the retention zones for Example 3 is the same as described in Example 1. Table 2 shows specific compositions for the retention materials.

Example 4 Example 4 demonstrates an essentially free region of expanded liquid in an absorbent product in which the entire front or back of the product does not store the liquid and can be used for some other designed purpose or attribute. Example 4 shows an embodiment of this aspect of the present invention wherein the liquid is stored only in the central target zone and in the intermediate front and end frontal zones of figure 2. The frontal filling pattern also shows a progression of uniform filling in Example 4 as a demonstration of the liquid filling control provided by the current invention. The essentially liquid-free region can be located on either side in the absorbent product including the front or crotch regions. Alternate filling patterns and progression can also be designed.

Example 4 uses the emergence and distribution material and the multifunctional material described in Example 1 and shown in Figure 2. The position of the emergence and distribution materials is the same as shown in Figure 2, but can change to completely isolate the essentially liquid-free region from the liquid insult or liquid dispensed by completely removing any component of this region.

Example 4, as tested, contains liquid within the adjacent distribution material up to the intermediate rear and rear end zones showing that storage of the liquid will be possible with the proper design of the retention materials and with the proper design of the system. The retention materials for Example 4 are compositionally the same as described for Example 1. The details for the retention materials of Example 4 are shown in Table 2. The central zone and the front and intermediate end retention zones The front positions are attached to the distribution material as described for Example 1. The retention positions of the rear and intermediate rear zones are left empty., therefore in Table 1 there is no entry for a fill ratio for the rear end area ratio: central (for example 3: 5). The filling ratio of the central end zone: front (e.g., 3: 1) of Example 4 as shown in Table 1 falls within the range of the invention. The emergence material was placed symmetrically on the central zone as shown in Figure 2, partially overlapping the retention material of the front intermediate zone and the hollow area of the posterior intermediate zone.

Example 5 - This example illustrates an end to which a structure can achieve a remote location of the liquid through effective selection and assembly of materials providing the functions of emergence, distribution and retention as described by this invention.

As mentioned above, the movement of the liquid in and out of the absorbent system is controlled by a capillary difference from one material in relation to the other throughout the life cycle of the system. As mentioned above, the amounts of contact area between the distribution and retention materials greatly affects the liquid transfer rates between them. In Example 5, the contact area of retention material-distribution materials is provided by alternating layers of these materials in the areas of the product where both materials are located.

The structures provided by this invention can be arranged to provide an essentially liquid-free zone which can be used for some other additional purpose or other attribute designed such as to create a region of improved dryness, a superior air circulation or a hollow area for the stool storage. The location of the essentially liquid-free zone can be anywhere in the absorbent product depending on its functional purpose. In Example 5 this essentially liquid-free zone is located in the posterior region of the product in the posterior intermediate zone and in the posterior end zone to provide improved dryness and health to the skin in the crotch area, and also results in a 3: 1 fill ratio of the area of less than 1.0.

Example 5 was assembled to achieve a liquid filling pattern stored completely in the front of an absorbent product shaped with a crotch width of 6.35 cm (2.5 inches). The longitudinal dimension of the absorbent was 31.75 cm (12.5 inches) and the transverse dimension varied in each zone. The product was divided transversely into five zones to determine the fill ratio, each zone equal to one fifth of the overall absorbent length. As a result of the variable transverse dimension in such shaped product, each zone contains different areas of absorbent materials as measured in square centimeters. For Example 5 the area of the absorbent structure per zone was as follows: end zone 1-76 cm2, intermediate zone 2-57.3 cm2, central objective area 3- 45.25 cm2, intermediate zone 4-78.65 cm2, and zone of end 5-77.4 cm2.

The emergence material used in Example 5 was composed of pulp coform material. The fabric comprised a 50 percent blend of cellulosic fluff available as IP Supersoft from International Paper Corporation and 50 percent meltblown fibers from polypropylene macrofibre, using a resin available in pellets from Himont USA, Inc., of Wilmington, Delaware (now operating as Montell). The fabric was spray treated during formation with a Triton X-102 surfactant solution to obtain an addition rate of 0.5 percent by weight. The meltblown polypropylene is believed to have fiber sizes ranging from about 10-113 microns and an average fiber size of 50.2 microns. The fabric has a basis weight of 194 gsm, a density of 0.037 g / cm 3 and was formed according to the process described in U.S. Patent No. 4,100,324 issued to Anderson and Sokolowski.

The emergence material was placed on one side of the liner material which was composed of 100% polypropylene spunbonded material where the fibers had a bilobal cross section and which is available from Kimberly-Clark Corporation. The liner material was prepared at 27 gsm using polypropylene resin available in pellet form from Himont USA, Inc., of Wilmington Delaware (now operating as Montell). The liner material was made wettable using a three roller / reverse roll liquid application system by coating a Triton X-102 surfactant solution on the spin-bonded liner to achieve 0.25 percent by weight addition level. .

The distribution material was compositionally the same as the emergence material. In addition, the distribution material has been etched using heated calendering rolls operating at 3 meters per minute with upper roll surface temperatures (which has a sinusoidal wave engraving surface) of 102 ° C and a bottom roll (the which has a smooth surface) of 107 ° C. The fabric was passed through the fastening point, collected on a roller, and then unrolled and fed through the engraving point a second time. The resulting recorded coform distribution material has a basis weight of 95 gsm and a cloth density of 0.075 g / cm3. This material achieved an equilibrium vertical transmission height of 10.2 cm after 15 minutes.

The retention material was composed of 50 percent by weight melt blown microfiber material of 50 percent by weight super absorbent granules Sanwet IM 1500 supplied by Hoechst Celanese Corporation of Charlotte, North Carolina. The melt blow was produced with polypropylene resin available in pellet form from Himont USA, Inc., of Wilmington, Delaware, (now operating as Montell). The fabric was spray treated during formation with a Triton X-102 surfactant solution to obtain an addition rate of 0.5 percent by weight. The melt super absorbent / blown retention material was prepared at 123 gsm, 0.106 g / cm 3, and had a saturated salt water solution capacity of 8.5 g / 1 of 32 grams of liquid per gram of fabric tested.

To evaluate the absorbent system with human subjects, individual products were prepared. The shaped pieces of each component in this Example 5 were cut, weighed and assembled. The product was assembled using multiple layers of each type of material. Four layers of distribution material were prepared using the complete product form, thereby covering all five absorbent zones. Seven layers of the retention material were cut to cover the end zone 1 and the intermediate zone 2. The distribution and retention materials were layered from the bottom (outward side of a user) of the product as follows: 1 layer distribution, 3 retention layers, 1 distribution layer, 2 retention layers, 1 distribution layer, 2 retention layers, 1 distribution layer. To avoid changing the shorter retention material, the layers were joined together using localized ultrasonic bonding points. In addition, the sonic junction lines parallel to the longitudinal axis of the product were added to support the connection between the layers. Approximately 580 cm2 of contact area between the distribution layers and the layers of retention materials was achieved.

A moderate sized distribution layer covering the end zone 1, the intermediate zone 2, the central objective zone 3 and the intermediate zone 4 was placed on top of the distribution / retention laminate. A smaller distribution material was placed on the upper part which had been cut to cover the intermediate zone 2, the central objective area 3 and the intermediate zone 4. Finally three layers of emergence material were cut to cover the area of end 1, intermediate zone 2, central zone 3 and intermediate zone 4. The completed assembly was covered with the spin-bound liner which was thermally sealed around the edges to a polyethylene polymer film.

Three diapers with this absorbent set were tested on infants who weighed around 12-15 pounds. Salt water was supplied at body temperature (37 ° C or 98.6 ° F) a solution of 8.5 grams of sodium chloride per liter) to the target area of each diaper with an insult of 60 ml at a flow rate of 15 cc / second through a piece of plastic tube with about 0.3175 cm (0.125 inches) in diameter. One end of the tube was connected to a pump and the other end was placed in the baby's diaper and placed in the target area; Aliquots of salt water were added every 15 minutes until runoff occurred. The diapers were removed from the users and the absorbent materials were cut and weighed to determine the filling rate of the absorbent system. Three products contained 257, 242 and 259 grams of salt water when the runoff occurred, respectively.

Absorbent materials were cut into 1-inch sections along the longitudinal axis of the product, starting at the front of the product. When a 1-inch (2.54 cm) section was located through two zones, such as end zone 1 and intermediate zone 2, it was presumed that the fluid was also located in both zones. Therefore half of the fluid in that section was added to each total zone.

The average fluid per zone was as follows: end zone 1; 128.3 grams, intermediate zone 2; 23.25 grams, central objective area 3; 21.5 grams, intermediate zone 4; 9.5 grams, end zone 5; 0 grams This results in a fill ratio of the area of 3: 1 of 0.16, or even less than 1: 1, clearly demonstrating the ability of the invention to achieve the location of the liquid through the effective selection and assembly of materials. which provide the functions of emergence, distribution and retention.

The test results for "Examples 1-4 are shown in Table 1. Table 1 describes the amount of liquid in grams in each zone after each insult where N is the number of tests, the amount of discharge in milliliters after each insult and in total, a calculated weight ratio of liquid in the central zone for each end zone and a capacity saturated in grams Note that in the tables, the proportion of the center end: front is labeled 3: 1 and the center end: posterior ratio is labeled 3: 5 and the zones are numbered 1-5 from the front to the back with the central zone being zone number 3. The amount of liquid in grams in each zone after the insult is determined by X-ray image as discussed in the Test Methods section.

Table 2 shows the construction materials for liquid retention in each of the zones in Examples 1-4. Note that Examples 3 and 4 which have empty storage areas do not show a composition in Table 2. In Table 2 the basis weight in grams per square meter (gsm) of the material used in the example is given first, the percent by weight of super absorbent is then given, followed by the percent by weight of pulp, the stabilization method and the density in grams / cubic centimeter. Favor 870 is commercially available from Stockhausen Company, of Greensboro, North Carolina, 27406 and is a super-absorbent surface highly bonded in cross-fbrma. AFA 94-21-5 is a 1400 micron polymerized polyacrylate suspension particle from the Dow Chemical Company of Midland, Michigan. CR 1654 pulp is commercially available from Kimberly-Clark Corporation of Dallas, Texas and is a soft wood pulp from the south. The HBAFF is available from Weyerhaeuser Corporation of Tacoma, WA, and is a high volume additive formaldehyde-free pulp which is a southern softwood pulp fiber cross-linked with an improved wetting module. The HBAFF has a chemical treatment which is set in a curl and twisted, in addition to imparting an added dryness and wet stiffness and elasticity to the fiber. The "3% Binder" referred to in Table 2 is a binder fiber used to mechanically stabilize the absorbent structure and is from Danaklon a / s, located in Engdraget 22, KD-6800 Varde, Denmark, and they are sheath fibers / conjugate PE / PP core of 2 deniers cut into 6 mm sections. The "Stabilized Kymene" component refers to a particular used liquid binder which was a Kymene® 557LX binder available from Hercules, Inc., of Wilmington, Delaware.

TABLE 1 TABLE 1 (continued) * = Designation absence of retention in the area TABLE 2 COMPOSITION COMPOSITION OF STORAGE Table 2 (Continued) The results given above show that absorbent articles with low filling ratios can be successfully produced according to this invention. In order to illustrate the magnitude of the improvement that this invention brings to the field of products for personal care and the transport and storage of liquid, comparative data were collected on a number of diapers currently commercially available. The diapers were each tested after three insults of 80 ml each separated by 30 minutes according to the Mist evaluation test. Each type of diaper was tested 3 times, the saturated diaper capacity (S.C.) in grams was also determined. Table 3 showed the liquid distribution in each zone as determined by the X-ray image and also includes the actual discharge and load. The data in Table 3 are in milliliters. Table 4 shows the fill ratios using the data in Table 3. Table 5 shows the liquid partitions and zone proportions for the same types of diapers using the cut and weigh method. Table 6 shows the zone and liquid partition ratios after each of the three insults for Example 1 and two commercial diapers using the cut and weigh method. The data very surprisingly shows the difference in fill rates between the invention and the diapers currently marketed for the typical commercially available wide crotch diaper. The diapers were all tested on the market in the summer of 1995. Note that the amount of liquid in each zone used to develop the data in Table 3A was determined according to the X-ray image. The data in Table 3B is determined by the method of cutting and weighing.

Huggies® and Kleenex® are trademarks of Kimberly-Clark Corporation of Dallas, Texas, which can be contacted at Department HC3G-32, PO Box 2020, Neenah, Wisconsin 54957-2020. The Kleenex® Huggies® diapers that were tested were the Ultratrim® diapers for Ella, step 3, medium (16-28 pounds) and the Ultratrim® diapers for El, step 3, medium (16-28 pounds).

Pampers® and Luvs® are trademarks of Procter and Gamble Corporation of Cincinnati, Ohio. The Pampers® diapers tested were the Pampers® Stretch Boy diaper, size 3 (16-28 pounds).

The tested Luvs® diapers were Ultra Leakguards size 3 (16-28 pounds) for boys and girls.

The Wonder Drys® is a brand of Paragon Trade Brands, 33325, 8th Avenue South, Federal Way, WA 98003. The tested Wonder Drys® diapers were ultra-thin medium (12-24 pounds) boys and girls.

Drypers® is a trademark of Drypers Corporation, PO Box 8830, Vancouver, WA 98666-8830. The tested Drypers® diapers were medium size (12-24 pounds) for boys and girls.

Loving Touch® is a brand of Paragon Trade Brands. Tested Loving Touch® diapers were the basic medium style (12-24 pounds), boys and girls and ultra-thin 3 (12-24 pounds) for boys and girls.

Fitti® is a brand of Associated Hygienic Products, LLC, Duluth, Georgia 30136. Fitti® diapers tested were medium (12-24 pounds) for boys and girls.

TABLE 3 TABLE 3 (Continued) TABLE 3 (Continued) TABLE 4 Insult Insult Insult TABLE 5 - - Liquid retained in grams after 3"Insult. Fill ratio 3 ° Insult TABLE 6 Liquid retained in grams after each insult. Filling ratio As can be seen, given the results given above, an absorbent article is provided where much of an insult moves out of the target area. This provides a breakthrough in absorbent technology and product design for personal care. In addition, the discharge is greatly reduced compared to conventional personal care products.

Although only some exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications to the exemplary embodiments are possible without departing materially from the teachings and novel advantages of this invention. Therefore, all such modifications are intended to be included within the scope of the invention as defined in the following claims. In the claims, the media clauses plus function are intended to cover the structures described herein as carrying out the recited function and not only the equivalent structures but also the equivalent structures. Therefore even when a screw and a nail may not be structural equivalents in the sense that a nail employs a cylindrical surface to secure joints to the wooden parts, while a screw employs a helical surface, in the environment of the fastening Wood parts, a nail and a screw can be equivalent structures.

Claims (23)

R E I V I N D I C A C I O N S

1. A personal care product comprising an absorbent system which can be transversely divided into a central zone adjacent to two intermediate zones which are adjacent to two end zones where said zones are of almost equally dimensioned where a proportion of the amount of liquid stored in the central zone to the amount of liquid stored in at least one of said end zones 30 minutes after a first insult is less than 5: 1.

2. The personal care product as claimed in clause 1, characterized in that said proportion is less than 5: 1 after a second insult delivered 30 minutes after said first insult.

3. The personal care product as claimed in clause 1, characterized in that said proportion is less than 5: 1 for each of the three insults separated by 30 minutes.

4. The personal care product as claimed in clause 1, selected from the group consisting of diapers, training pants, absorbent undergarments, incontinence products for adults . 78 and products for women's hygiene. "

5. The product as claimed in clause 4, characterized in that the product for personal hygiene is a product for the hygiene of women.

6. The product as claimed in clause 4, characterized in that said product for personal hygiene is a product for adult incontinence.

7. The product as claimed in clause 4, characterized in that said product for personal care is a diaper.

8. The diaper as claimed in clause 7, characterized in that it has a crotch width of at least 7.6 cm.

9. The diaper as claimed in clause 7, characterized in that it has a crotch width of at most 5 cm.

10. The diaper as claimed in clause 7, characterized in that it has a filling ratio of less than 3: 1.

11 * The diaper as claimed in clause 7, characterized in that it has a filling ratio of less than 2.5: 1.

12. A personal care product as claimed in clause 1, characterized in that it has less than 40 ml of discharge of three insults of 80 ml delivered at a rate of 15 ml / second at intervals of 30 minutes.

13. A diaper comprising a liner from side to body in communication of the liquid with an emergence layer, a multifunctional material and a distribution layer, wherein said diaper has a front and a backing and said distribution layer transports the liquid to the zones of intermediate retention and front and rear end outward from a central target area so that the diaper has a fill ratio of less than 5: 1.

14. The diaper as claimed in clause 13, characterized in that one of said end retention zones is essentially free of liquid.

15. The diaper as claimed in clause 14, characterized in that the essentially liquid free zone is used for a purpose selected from the group consisting of providing an improved dry region, providing superior air circulation and providing a hollow area for a BM storage.

16. The diaper as claimed in clause 13, characterized in that one of the intermediate retention areas is essentially free of liquid.

17. The diaper as claimed in clause 16, characterized in that the essentially liquid-free zone is used for a purpose selected from the group consisting of providing a region of improved dryness, providing superior air circulation and providing a hollow area for BM storage.

18. The diaper as claimed in clause 13, characterized in that it has less than 40 ml of total discharge of three insults of 80 ml delivered at a rate of 15 ml / second at intervals of 30 minutes.

19. The diaper as claimed in clause 13, characterized in that it has a crotch width of at least 7.6 cm.

20. The diaper as claimed in clause 13, characterized in that it has a crotch width of at most 5 cm.

21. The diaper as claimed in clause 13, characterized in that said retention zones contain an absorbent composition comprising from 20 to 85 percent by weight of super absorbent, from 80 to 15 percent by weight of pulp, of from a positive amount to about 10 percent by weight of a binder component and which has a density between about 0.1 and 0.4 g / cc.

22. A personal care product comprising an absorbent system which can be divided transversely into a central zone adjacent to two intermediate zones which are adjacent to two. end zones wherein said zones are almost equally dimensioned and wherein a proportion of the amount of liquid stored in the central zone to the amount of liquid stored in at least one of said end zones 30 minutes after an insult is of less than 2.5: 1.

23. The personal care product as claimed in clause 22, characterized in that said filling ratio is less than 1.1. SUMMARY An absorbent is provided for personal care products which can be divided into almost a central area, two intermediate zones and two equally dimensioned end zones where the ratio of the amount of liquid stored in the central area to the amount of liquid stored in at least one of the end zones 30 minutes after an insult is less than 5: 1. Such an absorbent may be used in personal care products such as diapers, training pants, women's hygiene products, absorbent underwear, adult incontinence products, and the like.