MXPA98008431A - Disposable absorbent product resistant to ace - Google Patents

Abstract

An adhesive is described that exhibits desired oil resistance and processing properties. The adhesive is suitable for use in elastic compounds and disposable absorbent products. In one embodiment, the adhesive exhibits the following properties: an elastic modulus value that is greater than about 4 x 10 at five dines per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second, and an elastic modulus value in oil that is greater than about 4 x 10 at five dines per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second; a viscosity value of less than about 40,000 centipoise at a temperature of about 275 ° F, and a viscosity value of more than about 60,000 centipoise at a temperature of about 250

Description

DISPOSABLE ABSORBENT PRODUCT RESISTANT TO OIL Background of the Invention Field of the Invention The present invention relates to adhesives suitable for use in elastic compounds and disposable absorbent products that are insulted with a solvent comprising an oil. More particularly, the present invention relates to an adhesive that exhibits desired rheological and processing properties, such as to provide effective oil resistant bonds.

Description of Related Art The use of adhesive materials in absorbent personal care products is generally known. Such adhesive materials are generally employed in absorbent products such as diapers, training underpants, adult incontinence products, and feminine care products in order to hold various parts of the product together or to maintain a particular part of the product. a desired place.

A disposable absorbent product is designed usually to be insulted during use with various liquids such as water, salt water and body fluids such as urine, menstrual fluids and blood. Obviously, it is desired that the disposable absorbent product retain its integrity during use and does not allow the draining of such liquids that insult the product. As such, the adhesive materials used in the disposable absorbent personal care products are not generally affected by such fabrics so as to not essentially lose their adhesive properties during use by a user.

However, in addition to such liquids, the disposable absorbent products may also be insulted with oil-based solvents, such as baby oil, lotions, ointments, petroleum jellies, sunscreens or other products for the skin care. Unfortunately, the current adhesive materials used in the disposable absorbent products have been found to be not essentially resistant to such oil-based solvents, and, as such, essentially lose their adhesive properties during use by the user when the disposable absorbent product is insulted with such solvent based on oil. This typically results in several parts of a disposable absorbent product detached from each other and / or at an increased incidence of liquid run-off.

For example, a composite comprising elastic yarns sandwiched between two substrates can be used within an absorbent product for improved comfort and notch for a wearer or for improved absorbent properties of the disposable absorbent product by reducing the incidence of runoff. An adhesive used to prepare such a composite should generally not only hold the elastic threads in place between the two substrates but also prevent the elastic threads from delaying the substrates during use. If such an adhesive is not resistant to oil and the elastic compound is insulted with an oil-based solvent, the elastic yarns can be delaminated from the substrates, possibly resulting in increased liquid run-off as well as reduced notch and comfort for the user.

It is therefore desired to develop an adhesive which is generally resistant to oil and yet which is easy to process so as to be used efficiently in the preparation of an elastic compound or a disposable absorbent product. Such elastic compound or disposable absorbent product will therefore retain its integrity better during use by a user when the elastic composite or disposable absorbent product is contacted with an oil-based solvent during such use.

Synthesis of the Invention In one aspect, the present invention relates to an adhesive which is essentially resistant to oil-based solvent and which is easy to process.

In an embodiment of the present invention, an adhesive exhibits the following properties: a) an elastic modulus value that is greater than about 4 x 105 dies per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second; b) an elastic modulus value in oil that is greater than about 4 x 105 days per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second; c) a viscosity value of less than about 40,000 centipoises at a temperature of about 275 ° F; Y d) a viscosity value of more than about 60,000 centipoise at a temperature of about 250 ° F.

In another aspect, the present invention relates to to an elastic composite comprising elastic threads located between a first substrate and a second substrate wherein the first substrate is attached to the second substrate by an adhesive exhibiting the desired properties described herein. The elastic compound is suitable for use in disposable absorbent products.

In one embodiment of the present invention, an elastic composite comprises elastic yarns located between a first substrate and a second substrate wherein the first substrate is attached to the second substrate by an adhesive exhibiting the desired properties described herein.

In another aspect, it is desired to provide a disposable absorbent product such as an infant diaper, which product is essentially oil resistant, so that the disposable absorbent product retains substantially its integrity during use by a wearer when the disposable absorbent product is put in contact with an oil-based solvent during such use.

In one embodiment, these objectives are achieved in a disposable absorbent product comprising a top sheet, a bottom sheet attached to the top sheet, an absorbent structure placed between the top sheet and the bottom sheet, and an elastic composite fastened to the top sheet , in wherein the elastic composite comprises elastic threads located between a first substrate and a second substrate wherein the first substrate is attached to the second substrate by an adhesive exhibiting the desired properties described therein.

Detailed description of the invention It is desired that the adhesive useful in the present invention is not essentially affected when placed in contact with an oil-based solvent. As such, the adhesive essentially maintains its adhesive properties when contacted with such an oil-based solvent or otherwise exposed to it.

As used herein, the term "adhesive" is used to mean that property of any material that allows the material to bond together to the substrates by surface clamping. Such bonding can result from the application of a pressing force, in the case of a pressure-sensitive adhesive material, or from a sufficiently high temperature, in the case of a hot-melt adhesive, to make contact and bond the adhesive material to an adhesive. substrate The adhesive useful in the present invention is beneficially not essentially soluble and not dispersible in an oil-based liquid or solvent, which is to be contact with a disposable absorbent product or compound comprising the adhesive. Such liquids include water, an aqueous salt water solution of 0.9 percent by weight, synthetic urine, and body fluids such as urine, menstrual fluids, and blood. Such oil-based solvents include baby oils, lotions, ointments, petroleum jellies, sunscreens, or other skin care products. Because the adhesives useful in the present invention are essentially insoluble but dispersible in the liquid or solvent to be contacted with the adhesive, the adhesive properties of the adhesive will not be negatively accepted in essential form when the adhesive is placed on the adhesive. contact with the liquid or solvent. This is, generally in contrast to the use of an adhesive which is essentially soluble or dispersible in the liquid or solvent to be contacted with the superabsorbent since, with the contact of the solvent liquid with the essentially soluble or dispersible adhesive, such an adhesive it will become essentially soluble or dispersible within the liquid or solvent so as to no longer exhibit essentially its desired adhesive properties.

As used herein, the term "essentially insoluble" is meant to mean that essentially no soluble fraction of the adhesive can be detected in a liquid or solvent contacted with the adhesive by such known laboratory techniques as measurements of intrinsic viscosity or light scattering experiments, such as those described in the work "Principles of Surface Chemistry and Colloid" by Paul Hiemenz (1977) incorporated herein by reference.

As used herein, the term "essentially non-dispersible" is meant to mean that, when brought into contact with a liquid or solvent, essentially no dispersible fraction of the adhesive material, within a range of size distribution of about one A micrometer around 100 micrometers can be filtered out of the solvent liquid by using conventional filter paper.

Therefore, solubility studies can, in theory, be used to identify oil-resistant adhesive polymers. In general, if an adhesive (or its components) is soluble or can be swollen by mineral oil or other oil-based solvents found in skin care products, the oil will typically weaken and make the adhesive plastic, resulting in poor bonds and will make the adhesive resulting in poor joints and will make the adhesive essentially less useful. However, it has been found that oil-based solubility studies are difficult to carry out and often can not measure the effects of time and temperature on oil solubility. As such, the solubility measurements are believed to be, at best, only identify which adhesive polymers should be considered for oil resistant applications.

In contrast, it has been found that rheological measurements are much more important in predicting the ability of an adhesive to maintain its adhesive properties when insulting with an oil-based solvent. Rheological measurements have been found to consider the effects of time and temperature on adhesion and have been found to show the effects of oil solubility. However, in order to carry out an acceptable oil resistant bond, the viscosity of the adhesive has been found to be necessary to consider. In general, the viscosity of the adhesives must be sufficiently low at the temperature and application of the adhesive as to "wet" or otherwise make intimate contact with the surface of the film substrates or mechanically wrap the porous nonwoven substrates. Once the adhesive makes intimate contact with the substrate, the interfacial adhesion forces will typically increase the adhesive bond. The rheological properties after the insult with an oil-based solvent must be sufficient to resist cohesive failure when subjected to the forces of deformation of normal use, such as walking, crawling or other movements of a user or carrier. It has been found in the present invention that both desired rheological and viscosity properties of an adhesive must be satisfied in order for the adhesive to achieve the desired properties. oil-resistant adhesive properties desired.

The desired rheological properties of the adhesive material of the present invention include effective elastic modulus and elastic modulus values in oil. The elastic modulus value of an adhesive material (G ') that it wants to represent the stress in phase with the tension in a sinusoidal shear deformation divided by the tension; it is a measure of the energy stored and recovered per cycle when different systems are compared to the same voltage amplitude. It is desired that the adhesive material does not exh an elastic modulus value that is too low so that the adhesive lacks sufficient cohesive strength to resist delamination.

Thus, the adhesive of the present invention exhibits an elastic modulus value that is beneficially greater than about 4 x 105 dies per square centimeter, suitably greater than about 6 x 105 per square centimeter, more suitably more than about 8. x 10 days per square centimeter and up to about 8 x 107 days per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second, as measured according to the methods described in the section of "Test Procedures" given here-.

The Elastic Modulus Value in oil of an adhesive material is intended to represent the elasticity coefficient representing the stress stress ratio as the adhesive material is deformed under a dynamic load where the adhesive material has been placed in contact with a solvent based on of oil before its evaluation. It is desired that the adhesive material does not exhibit an elastic modulus in oil value that is too low so that the adhesive lacks sufficient cohesive strength to resist delamination.

Therefore, the adhesive of the present invention exhibits an elastic modulus value in oil that is beneficially greater than about 4 x 105 dies per square centimeter, suitably greater than about 6 x 105 dimes per square centimeter, more adequately more than about 8 x 105 di is per square centimeter, and up to about 8 x 107 days per square centimeter at 40 ° C through the frequency range of about 0.1 to about 100 radians per second, as measured according to to the methods described in the test procedure section given here.

The adhesive of the present invention desirably exhibits an elastic modulus value in oil that is beneficially at least about 50 percent, suitably at least about 75 percent, and more suitably at least about of 90 percent of the module value elastic of the adhesive.

The desired processing properties of the adhesive material of the present invention include exhibiting effective viscosity values. The viscosity value of an adhesive material is intended to represent the apparent viscosity of the adhesive material. In general, it is desired that the material of the present invention exhibit effective viscosity values at temperatures of about 250 ° F and about 275 ° F. The temperature of about 275 ° F is a typical minimum temperature used in applying adhesives to a non-woven substrate to prepare an elastic compound or a disposable absorbent product. Temperatures below about 275 ° F are generally impractical to use because the adhesive will generally be too viscous to properly apply to a non-woven substrate to result in an effective adhesive bond. Temperatures above about 375 ° F are generally impractical to use because the substrate such as the polypropylene nonwoven onto which the adhesive is being applied may be damaged by such a high temperature.

It is therefore desired that the adhesive material does not exhibit a viscosity value, at a temperature of about 275 ° F, which is too high, so that the adhesive does not effectively penetrate a porous substrate not effectively wet, or otherwise make intimate contact, with a substrate, resulting in a poor union. As such, the adhesive of the present invention exhibits a viscosity value, at a temperature of about 275 ° F, which is beneficially less than about 40,000 centipoise, suitably less than about 35,000 centipoise, and more suitably less than about 30,000 centipoises, as measured according to the methods described in the test procedures section given here.

It is also desired that the adhesive material does not exhibit a viscosity value at a temperature of about 250 ° F., which is too low so that the adhesive does not set or solidify very quickly after application of the adhesive, a substrate, since the adhesive may migrate or otherwise flow to undesirable places on the substrate. Thus, the adhesive of the present invention exhibits a viscosity value, a temperature of about 250 ° F, which is beneficially greater than about 60,000 centipoise, suitably greater than about 65,000 centipoise, more suitably more than about 70,000 centipoise. centipoises and up to about 1,000,000 centipoises, as measured according to the methods described in the test procedure section given here.

The adhesives useful in the present invention can be of any known type, such as an adhesive thermoplastic thermoforming, a reactive adhesive or the like. An example of a thermoplastic hot melt adhesive includes an adhesive material comprising a polybutylene polymer, a hydrocarbon adhesive resin, and a wax, available from High Findley, Inc., under the designation Findley H9220. A description of the compositions of the hot-melt adhesives can be found, for example, in the text "Text of Technology of Elastomer CRC", edited by Nicholas P. Cheremisinoff (Press CRC, 1S93), Chapter 24, incorporated herein by reference.

Examples of the reactive adhesives include two parts of polyurethanes, wet-set polyurethanes, and hemoxies. The chemistry of such reactive adhesives is known to those skilled in the art and can be found, for example, in the work "Contemporary Polymer Chemistry" by Harry Alcock and Frederick Lampe (Prentice Hall, 1990), incorporated herein by reference.

A more uniform dispersion of the adhesive will typically result in less adhesive being necessary to achieve effective and efficient adhesion of the parts within a disposable absorbent product or compound as compared to where the adhesive is not uniformly dispersed. In addition, the upper and lower limits of the amount of adhesive to be used in a compound or in a disposable absorbent product may be affected by the nature of the materials comprising the disposable absorbent product or compound. Generally speaking, one would like to use no adhesive as much as possible.

In one aspect, the present invention relates to an elastic compound, such as, for example, a containment fin, for use in a disposable absorbent product. The elastic composite has an edge proximal to that adapted to be attached to the disposable absorbent product and a distal edge opposite said proximal edge. The elastic composite comprises a first substrate layer, typically a non-woven material, a second substrate layer, typically a non-woven material, and an elastic material located between the first and second substrate layers, typically on one side of the distal edge of the elastic compound. In a specific embodiment of this aspect of the present invention, the elastic members are adhesively bonded to the first substrate layer. In a second embodiment of this aspect of the present invention, a pattern of intermittent adhesive bonds the first and second layers together, and also intermittently bonds the elastic member to the first and second layers. In a third embodiment of this aspect of the present invention, the first and second layers are formed of a single integral piece of material and which is folded on itself. A pattern of intermittent adhesive joins the first and second layers together and, one intermittently, the elastic member to the first layers and second, such elastic compounds are described, for example, in the co-pending patent application of the United States of America series No. 08 / 213,338, filed on March 14, 1994 by David P. Kielpikowski.

In another aspect, the present invention relates to a method for making an elastic composite, such as a containment fin, for use on a disposable absorbent product. The method comprises providing a first layer of a substrate, such as a nonwoven material that moves in a first direction. The elastic members moving in the first direction are attached to the first layer in a laterally spaced relationship. A second layer of the substrate material moving in the first direction is adhesively bonded to the first layer to form a composite having the first and second longitudinal side edges. The second layer of the substrate material is adhesively bonded to the first layer of substrate material, so that the elastic members are located between the first and second layers in such a way that a first pattern of adhesive bonds is located between the elastic members. The composite is cut into strips in the first direction between the elastic members to form two strip compounds. The strip compounds are then cut in a second direction perpendicular to the first direction to form a containment fin.

In another aspect, the present invention relates to a method for making an elastic composite, such as a containment fin, for use on a disposable absorbent product. The method comprises providing a single integral part of a substrate such as a non-woven material, folding said piece of substrate to provide the first and second substrate layers; placing an elastic member between the first and second substrate layers; and intermittently applying an adhesive of the present invention to attach said elastic member to said first and second layers.

Specific examples of the materials suitable for use, the first and second layers of the substrate material include non-woven materials, such as polymers of meltblown or meltblown thermoplastics, such as polyolefins; the fabrics carded and joined; film materials such as polyolefin, ethylene vinyl acetate, ethyl methacrylate and polyester films; foam materials, such as polyolefin foams; woven materials, such as woven polypropylene, polyethylene or polyester fabrics; and the composites and laminates of the nonwoven, film, foam and fabric materials mentioned above. In a specific embodiment, the pyrrimera and second layers of the heat-meltable materials are formed of a non-woven material such as a polyethylene or polypropylene material joined by spinning or blowing with fusion. In another specific embodiment of the present invention, the first and second substrate materials are not integrally formed. That is, the first and second layers of the substrate material represent separate elements, which are not bonded in a different form than by thermal, adhesive or similar securing techniques. specifically, the first and second layers are not formed from an integral piece of material through a bending process. In another specific embodiment of the present invention, the first and second substrate layers are integrally formed. That is, the first and second layers are formed from a single piece of integral material through a bending process.

The elastic member may comprise any elastomeric material capable of being elongated by at least about 50 percent, alternately at least about 250 percent, alternately at least about 350 percent, and capable of recovering to a length within of at least about 75 percent, more particularly, at least about 50 percent of its elongated length (original length plus elongation). The elastic member may be in the form of tapes, individual threads, or other configurations. In one embodiment, the elastic member is in the form of individual elastomeric threads of elastomeric material. The elastic composite of the present invention may comprise a single elastic member or two or more elastic members. In a specific embodiment, the elastic member comprises a 470 decitex Lycra® yarn commercially available from E. I. Dupont de Nemours and Company. Alternatively, the elastic member may be composed of a thermoplastic elastomer or a natural or synthetic rubber commercially available from J. P. S. Elastomerics Corporation. The elastic member may also be comprised of a heat-activatable elastic material such as Pebax®, commercially available from Atochem, Inc., which may be activated with a heat treatment after association with the containment fin.

In another aspect, the present invention relates to a disposable absorbent product having a front portion, a back portion, and a crotch portion connecting the front and back portions. The crotch part has the opposite longitudinal side parts. The absorbent product comprises an upper sheet permeable to liquid, a lower sheet attached to the upper sheet, and an absorbent structure placed between the upper sheet and the lower sheet. A pair of elastic composite containment flaps extending longitudinally from the front of the disposable absorbent product to the back. The containment fins have a near edge and a distal edge opposite the near edge. The near edge is attached to the lower sheet in the crotch part and in the front and back. The fins of containment comprise a first layer of a heat-meltable material, a second layer of heat-meltable material, and an elastic member located between the first and second layers of the heat-fusible material adjacent the distal edge.

Those skilled in the art will recognize suitable materials for use as the top sheet and the bottom sheet. Examples of materials suitable for use as the topsheet are liquid-permeable materials, such as polypropylene or polyethylene spun-bonded having a basis weight of from about 15 to about 25 grams per square meter. Examples of materials suitable for use as the bottom sheet are liquid impervious materials, such as polyolefin films, as well as vapor permeable materials, such as microporous polyolefin films.

A suitable absorbent structure will generally comprise a fibrous matrix within which, for example, a hydrogel-forming polymeric material is dispersed such that the fibrous matrix constricts or entraps the hydrogel-forming polymeric material.

As used herein, the "polymeric hydrogel-forming material" is intended to refer to a high-absorbency material commonly referred to as a material superabsorbent Such high-absorbency materials are generally capable of absorbing an amount of a liquid, such as synthetic urine, a 0.9% by weight aqueous salt water solution, or body fluids such as menstrual fluids, urine or water. blood, at least about 10, suitably about 20, and up to about 100 times the weight of the superabsorbent material at the conditions under which the superabsorbent material is being treated. Typical conditions include, for example, a temperature between about 0 degrees centigrade to about 100 degrees centigrade and suitably environmental conditions, such as about 23 degrees centigrade and about 30 to about 60 percent relative humidity. With the absorption of liquid, the superabsorbent material typically swells and forms a hydrogel.

The superabsorbent material can be formed of an organic hydrogel-forming polymer material, which can include natural materials such as agar, pectin and guar gum, as well as the synthetic hydrogel-forming polymer materials. Synthetic hydrogel-forming polymeric materials include, for example, carboxymethylcellulose, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, copolymers of maleic anhydride, ethylene, polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone, polymers and acid copolymers. vinyl sulphonic, polyacrylates, polyacrylamides, and polyvinyl pyridines. Other suitable hydrogel-forming polymeric materials include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers, and mixtures thereof. The hydrogel-forming polymeric materials are preferably crosslinked slightly to make the material essentially insoluble in water but swellable in water. Crosslinking can, for example, be done by hydrogen bonding, covalent, ionic or Van der Walls. Suitable hydrogel-forming polymeric materials are typically available from various commercial vendors, such as The Dow Chemical Company, Hoechst Celanese, Allied Colloids Limited, or Stockhausen, Inc.

Suitably, the hydrogel-forming polymeric material is in the form of particles which in the non-swollen state, have maximum cross-sectional diameters in the range of from about 50 microns to about 1,000 microns, and more suitably within the range of from about 100 micrometers to about 800 micrometers, as determined by screening analysis according to the American Society for Testing and Materials (ASTM), test method D-1921. It will be understood that the particles of the hydrogel-forming polymeric material L fall within the size ranges described above may comprise particles solid, porous particles or agglomerated particles comprising many agglomerates of smaller particles within particles that fall within the described size ranges.

The hydrogel-forming polymeric material is present in the absorbent structure of the present invention in an amount effective to result in the absorbent structure being able to absorb a desired amount of liquid under the desired conditions. The hydrogel-forming polymer material is present in the absorbent structure of the present invention in an amount beneficially of from about 5 to about 95 percent by weight, suitably from about 15 to about 85 percent by weight, and more suitably from about 20 to about 80 percent by weight, based on the total weight of the hydrogel-forming polymeric material in the absorbent structure.

As used herein the term "fiber" or "fibrous" is intended to refer to a particulate material in which the length-to-diameter ratio of such particulate material is more than about 10. Inverse, a "non-fiber" or "non-fibrous" material is intended to refer to a particulate material wherein the diameter length ratio of such particulate material is about 10 or less.

The fibrous matrix can be formed by means of air-laid fibers, through a meltblown, a carding process, a wet process, or through essentially any other means known per se. Those experts in the art will form a fibrous matrix.

Methods for incorporating the hydrogel-forming polymeric material of the present invention into a fibrous matrix are known to those skilled in the art. Suitable methods include incorporating the hydrogel-forming polymeric material into the matrix during matrix formation, such as by air placement of the fibers of the fibrous matrix and the hydrogel-forming polymer material at the same time or by placing wet the fibers of the fibrous matrix and of the hydrogel-forming polymer material at the same time. Alternatively, it is possible to apply the hydrogel-forming polymeric material to the fibrous matrix after formation of the fibrous matrix. Other methods include sandwiching the polymeric hydrogel formed material between two sheets of material, at least one of which is fibrous and permeable to liquid. The hydrogel-forming polymeric material may be generally located uniformly between the two sheets of the material or may be located in discrete bags formed by the two sheets. The polymeric hydrogel-forming material can be distributed in the individual layers in a generally uniform manner or may be present in the fibrous layers as a layer or other non-uniform distribution.

The fibrous matrix can be in the form of an integrally and uniquely formed layer or a compound comprising multiple layers. If the fibrous matrix comprises multiple layers, the layers are preferably in fluid communication with one another so that a liquid present in a fibrous layer can flow or be transported to the other fibrous layer. For example, the fibrous layers may be separated by cellulosic tissue wrapping sheets known to those skilled in the art.

When the fibrous matrix comprises an integrally and uniquely formed layer, the concentration of the hydrogel-forming polymeric material can increase along the thickness of the fibrous matrix in a non-stepped and gradual manner or in a more stepped form. Similarly, the density may increase through the thickness in a non-stepped manner or in a staggered manner. The absorbent structures of the present invention may generally be of any size or dimension as long as the absorbent structure exhibits the desired absorbent characteristics.

The absorbent structure of the present invention it can also be used or combined with other absorbent structures, with the absorbent structure of the present invention being used as a separate layer or as an individual area or area with a larger composite absorbent structure. The absorbent structure of the present invention can be combined with other absorbent structures by methods well known to those skilled in the art such as by the use of adhesives or simply by layering the different structures together and holding together the composite structures with, for example, tissue.

The absorbent structures according to the present invention are suitable for absorbing many liquids, such as water, salt water, and synthetic urine, and body fluids such as urine, menstrual fluids, and blood, and are suitable for use in disposable absorbent products such as diapers, incontinent adult products, bed pads; in catameneal devices such as sanitary napkins, and plugs; and in other absorbent products such as cleansers, bibs, wound dressings, and surgical coats or covers.

Disposable absorbent products, according to all aspects of the present invention are generally subjected during use to multiple insults of a liquid of the body. Therefore, disposable absorbent products are desirably capable of absorbing multiple insults from body liquids in amounts to which absorbent products and structures will be exposed during use. The insults are usually separated from each other for a period of time.

Test Methods Elastic module The value of the elastic modulus of a sample of adhesive material is measured by an adhesive sample of non-suspended volume on any substrate. A sample of circular adhesive material was prepared having a thickness of about 2 to 3 millimeters and having a diameter of about 25 millimeters. The sample of adhesive material was placed on the bottom of two 25 mm diameter plates of a parallel plate apparatus on a mechanically driven oscillatory system Rheometrics RDS IIE Dynamic Spectometer, available from Rheometrics, Inc., 1 Possumtown Road, New Jersey 08854. The top plate is lowered onto the sample of adhesive material until the normal force gauge of the system detects a slight deflection. If necessary, the adhesive sample can be heated above its melting point in order to exhibit sufficient tackiness to adhere to the plates. The sample of adhesive material is then left to equilibrate in a forced air test chamber heated to a temperature of about 40 degrees centigrade, whose temperature was chosen to better simulate the body temperature of a wearer of a disposable absorbent product. A minicomputer is then used to govern the communication of a peak-to-peak cutting voltage of 1 percent to the sample of adhesive material, with the frequency of the application being controlled at a fraction of one radian / second. The value of elastic modulus for a sample of adhesive material can be calculated from the geometry factors, the peak-to-peak amplitude of the torsional force signal, and the phase lag of the torsional force output wave. Typically, a computer using a Rheometrics, Inc. program was used to control the operation of the mechanically driven oscillatory system and to calculate the elastic modulus value, as well as other rheological parameters, of the sample of adhesive material. The elastic modulus value can be displayed as a frequency sweep from about 0.1 radian per second to about 100 radians per second. The frequency range of about one radian per second to about 100 radians per second is the dynamic limit of the Rheometrics RDS IIE Dynamic Spectrometer mechanically driven oscillatory system used here, but this frequency range also corresponds to the frequencies (or time scales) ) that disposable absorbent products will typically find in the use, such as walking the baby while wearing a diaper.

Except as otherwise described herein, the value of elastic modulus and other rheological properties were measured as delineated in the standardized test procedure ASTM D4440-93"Standard Practice for the Rheological Measurement of Polymer Melts Using Dynamic Mechanical Procedures", incorporated in its entirety by reference. An additional explanation of the rheology and the measurement of the polymer can be found in "Properties of Viscosity of Polymers", by John D. Ferry, John Wiley S_Sons, third edition, pages 41-43 (1980) incorporated herein in its entirety pro reference Elastic Module in Oil Several samples of circular adhesive material were each prepared having a thickness of about 1 millimeter and having a diameter of about 25 millimeters. The samples of adhesive material were immersed in a baby oil composition comprising mineral oil, a fragrance, and tocopheryl acetate, available from Johnson & Johnson Consumer Products, Inc., of Skillman, New Jersey, for about 4 hours at around 40 degrees centigrade. A thickness of about 1 millimeter was used to better allow baby oil to penetrate through the full thickness of the the samples of adhesive material. The samples of adhesive material are then removed from the baby oil and dried with paper towels. About three of the samples of adhesive material of 1 millimeter thickness are then stacked together to obtain a single sample of single adhesive material having a thickness of about 2 to 3 millimeters. The sample of single adhesive material comprises a stack of samples of adhesive material of 1 millimeter thickness and was then placed on the lower of two 25 millimeter diameter plates of a parallel plate apparatus on a dynamically driven oscillatory system of dynamic spectrometer Rheometrics RDS IIE, and the elastic modulus value in oil for a sample of adhesive material was determined using essentially the same test procedure that was used to determine the elastic modulus value.

Viscocity The viscosity value of a sample of adhesive material was measured for a volume adhesive sample. A thermosel system viscometer, from the Brookfield series model DVIII RV, available from Brookfield Engineering Laboratories, Inc., of Stoughton, Massachusetts, was used. About 10.5 grams of a sample of adhesive material was placed in a heated thermosel and allowed to warm up for about 15 to 20 minutes at an initial temperature of about 400 degrees.

F (around 204 degrees Celsius). A stainless steel spindle, model SC27, was lowered into the heated thermosel and attached to the viscometer. The speed of the spindle was adjusted so that the percentage of displayed force values are from about 20 to about 80 percent of the full scale. A viscosity reading was taken every 5 minutes until the reading stabilized (values of torsional force of +/- 0.5 percent) for about 10 minutes. The stabilized reading was recorded as the viscosity value at that temperature. The fixed temperature point was then reduced to around 25 degrees F (around 14 degrees Celsius) and the process was repeated.

Except as otherwise described herein, the viscosity value was measured as delineated in the ASTM D3236-88 standardized test process "Standard Test Method for Apparent Viscosity of Thermofused Adhesives and Coating Materials", incorporated herein by reference. totality by reference.

E j e m p 1 o s Sample 1 is an adhesive material comprising a styrene-isoprene-styrene rubber block copolymer, hydrocarbon adhesive resins, and mineral oil, available from Ato Findley, Inc., 11320 Watertown Plank Road, Wauwatosa, Wisconsin, 53226, under the designation Findley H2525A.

Sample 2 is an adhesive material comprising a polyester polymer, polar adhesive resins and polyester plasticizers available from Ato Findley, Inc., under the designation Findley H9202.

Sample 3 is an adhesive material comprising a polyamide polymer, a rosin ester adhesive resin and a polar plasticizer, available from Ato Findley, Inc., under the designation Findley 1142-144A.

Sample 4 is an adhesive material comprising a polybutylene polymer, a hydrocarbon adhesive resin, a wax, and a nucleating agent, available from Ato Findley, Inc., under the designation Findley H9220.

Sample 5 is an adhesive material comprising a styrene-butadiene-styrene rubber block copolymer, hydrocarbon adhesive resins, and a mineral oil, available from Ato Findley, Inc., under the trade designation Findley H4013.

Sample 6 is an adhesive material comprising a styrene-isoprene-styrene rubber block copolymer, hydrocarbon adhesive resins, and mineral oil, available of Ato Findley, Inc., under the trade designation Findley H2096.

Sample 7 is an adhesive material comprising a polybutylene polymer, a hydrocarbon adhesive resin, and a mineral oil, available from Ato Findley, Inc., under the designation Findley H9214.

Samples were evaluated for the elastic modulus and elastic modulus values in oil according to the test methods described herein. The results of these evaluations are shown in Table 1.

Samples were evaluated for viscosity values according to the test method described here. The results of these evaluations are shown in Table 2.

T A B A Blaster Module v Values dß Blastic Module in Oil at 40 ° C (dines / cnt2) It is not an example of the present invention.

T A B L A Viscosity Values (centipoises) It is not an example of the present invention.

Several of the materials were used to prepare the composites comprising elastic yarns and non-woven substrates. The compounds were prepared by spiral spraying at about 15.5 grams of adhesive sample per square meter of substrate, at an adhesive temperature of between about 300 degrees F (about 150 degrees Celsius) to about 365 degrees F (about 185 degrees Celsius). degrees centigrade) and at an air temperature of 400 degrees F (around 200 degrees Celsius), using a 0.5 mm nozzle, on a polypropylene nonwoven substrate with two polyurethane threads, available from EI DuPont de Nemours Company under the designation LYCRA XA polyurethane threads under an elongation of about 250 percent, moving at a tissue speed of about 50 meters per minute and with an open time of about 0.25 seconds. After the application of the adhesive, a second layer of polypropylene nonwoven substrate was laminated onto the first nonwoven polypropylene substrate layer, sandwiching the polyurethane yarns between the two substrates.

The compounds insulted with oil were prepared by adding about 0.2 millimeters of the baby oil composition, comprising mineral oil as a fragrance, and tocopheryl acetate, available from Johnson & Johnson Consumer Products, Inc., of Skillman, New Jersey, directly to a united area 1 inch wide of a compound and leaving the compound insulted with oil balancing the ambient temperature (around 23 degrees Celsius) for about 2 minutes.

The peel strengths of both the compounds and the compounds insulted with oil were determined using a peel test T based on the test method ASTM D11875-61T, incorporated herein in its entirety by reference. The test instrument used was a Sintech tension tester model 1, available from MTS Corporation of Minneapolis, Minnesota. Compound samples 1 inch wide (in a stretched condition) were placed in the test devices of the voltage tester and pulled and separated at a speed of about 100 millimeters per minute. The full scale load was around 4540 grams. The results of these evaluations were shown in Table 3. The peel strength of each compound was expressed as a peak load, in grams. The energy was calculated as the area under the curve. The percentage loss was calculated by dividing the insulted values with oil between the uninsulted values with oil.

T A B A It is not an example of the present invention.

From these data, it is evident that sample 4 retained its peel strength after an oil insult better than the other samples. A minimum peak peel strength level of about 300 grams is generally desirable since this is the force typically required for the destruction of a typical nonwoven polypropylene substrate. Below such a minimum peak peel strength level, the adhesive bonds can potentially fail, allowing exposure of the elastic threads or other components of the product.

Even though the invention has been described in detail with respect to the specific incorporations of the same, it will be appreciated by those skilled in the art, to achieve an understanding of the foregoing, that alterations, variations and equivalents of these modalities can easily be conceived. Therefore, the scope of the present invention should be established as that of the appended claims and any equivalents thereof.

Claims (18)

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

1. An elastic composite comprising an elastic member located between a first substrate and a second substrate wherein the first substrate is attached to the second substrate by an adhesive exhibiting the following properties: a) an elastic modulus value that is greater than about 4 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; b) an elastic modulus value in oil that is greater than about 4 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; c) a viscosity value of less than about 40,000 centipoise at a temperature of about 275 degrees F; Y d) a viscosity value of more than about 60,000 centipoise at a temperature of about 250 degrees F.

2. The elastic compound as claimed in clause 1 characterized in that the adhesive exhibits a value of elastic modulus that is greater than about 6 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to around 100 radians per second.

3. The elastic compound as claimed in clause 1 characterized in that the adhesive exhibits an elastic modulus in oil value that is greater than about 6 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to around 100 radians per second.

4. The elastic compound as claimed in clause 1 characterized in that the adhesive exhibits a viscosity value of less than about 35,000 centipoise at a temperature of about 275 degrees F.

5. The elastic compound as claimed in clause 1 characterized in that the adhesive exhibits a viscosity value of greater than about 65,000 centipoise at a temperature of about 250 degrees F.

6. The elastic compound as claimed in clause 1 characterized in that the adhesive exhibits an elastic modulus value that is greater than about 6 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second, an elastic modulus value in oil that is greater than about 6 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second, a viscosity value of less than about 35,000 centipoise at a temperature of about 275 degrees F, and a viscosity value of more than about 65,000 centipoise at a temperature of about 250 degrees F.

7. The elastic compound as claimed in clause 6, characterized in that the adhesive exhibits a value of elastic modulus which is greater than about 8 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second, an elastic modulus value in oil that is greater than about 8 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second, a viscosity value of less than about 30,000 centipoise at a temperature of about 275 degrees F, and a viscosity value greater than about 70,000 centipoises at a temperature of about 250 degrees F.

8. The elastic compound as claimed in clause 1 characterized in that the adhesive comprises a polymer of polybutylene.

9. The elastic compound as claimed in clause 8 characterized in that the adhesive further comprises an adhesive resin, a wax and a nucleating agent.

10. The elastic compound as claimed in clause 1 characterized in that the first substrate is selected from the group consisting of nonwoven materials, carded and bonded fabrics, film materials, foam materials, and woven materials, and the second substrate is selected from the group consisting of nonwovens, carded and bonded fabrics, film materials, foam materials, and woven materials.

11. The elastic compound as claimed in clause 1 characterized in that the first substrate is a non-woven material and the second substrate is a non-woven material.

12. The elastic compound as claimed in clause 1 characterized in that the first substrate is a non-woven material prepared from a polyolefin and the second substrate is a nonwoven material prepared from a polyolefin.

13. The elastic compound as claimed in clause 1 characterized in that the elastic member is capable of being elongated by at least about 50 percent of the original length of the elastic member.

14. A method for preparing an elastic composite, the method comprises providing a first substrate, locating an elastic member on the first substrate, and then joining a second substrate to the first substrate with an adhesive, wherein the elastic member is placed between the first substrate. and the second substrate, and wherein the adhesive exhibits the following properties: a) an elastic modulus value that is greater than about 4 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; b) an elastic modulus value in oil that is greater than about 4 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; c) a viscosity value of less than about 40,000 centipoise at a temperature of about 275 degrees F; Y d) a viscosity value greater than about 60,000 centipoises at a temperature of around 250 degrees F.

15. The method as claimed in clause 14 characterized in that the adhesive exhibits a value of elastic modulus that is greater than about 8 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about of 100 radians per second, an elastic modulus value in oil that is greater than about 8 x 105 dies per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second, a value of viscosity of less than about 30,000 centipoise at a temperature of about 275 degrees F, and a viscosity value greater than about 70,000 centipoises at a temperature of about 250 degrees F.

16. The method as claimed in clause 14 characterized in that the adhesive comprises a polybutylene polymer.

17. The method as claimed in clause 15 characterized in that the adhesive further comprises an adhesive resin, a wax and a nucleating agent.

18. The method as claimed in clause 14 characterized in that the first substrate is selected from the group consisting of nonwoven, carded and bonded fabrics, film materials, foam materials, and woven materials, and the second substrate is selected from the group consisting of non-woven materials, carded and bonded fabrics, film materials, foam materials, and woven materials. SUMMARY An adhesive is disclosed that exhibits desired oil resistance and processing properties. The adhesive is suitable for use in elastic compounds and disposable absorbent products. In one embodiment, the adhesive exhibits the following properties: a value of elastic modulus that is greater than about 4 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; and an elastic modulus value in oil that is greater than about 4 x 105 days per square centimeter at 40 degrees centigrade through the frequency range of about 0.1 to about 100 radians per second; a viscosity value of less than about 40,000 centipoise at a temperature of about 275 degrees F; and a viscosity value of more than about 60,000 centipoise at a temperature of about 250 degrees F.